EP4712956A1 - Compositions and methods of use of agonists of epha receptors to treat diabetes - Google Patents

Abstract

Among the various aspects of the present disclosure is the provision of compositions and methods of use of agonists of EphA receptors to treat diabetes. Compositions include small molecule EphA agonists that normalize blood glucose in both type 1 and type 2 diabetes. Methods to treat both type 1 and type 2 diabetes with the disclosed EphA agonists are also described.

Description

Docket No.: 020153/WO TITLE OF THE INVENTION COMPOSITIONS AND METHODS OF USE OF AGONISTS OF EPHA RECEPTORS TO TREAT DIABETES CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority from U.S. Provisional Application Serial No. 63/502,256 filed on May 15, 2023, which is incorporated herein by reference in its entirety. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT This invention was made with government support under DK123301 awarded by the National Institutes of Health. The government has certain rights in the invention. MATERIAL INCORPORATED-BY-REFERENCE Not applicable. FIELD OF THE INVENTION The present disclosure generally relates to compositions and methods of use of small molecule agonists of EphA receptors to treat diabetes. BACKGROUND OF THE INVENTION Pancreatic alpha-cells secrete glucagon, the counter-regulatory hormone to insulin. Normally, insulin and glucagon work antagonistically to maintain euglycemia - insulin is released when blood sugar is high, and glucagon is released when it is low. Diabetes has been characterized by dysfunctional insulin secretion, but the disease is exacerbated by hypersecretion of glucagon as well. Published data suggest that normalizing the glucagon axis could ameliorate or even cure diabetes. Pharmaceutical efforts have focused on blocking glucagon action, with glucagon receptor antagonists, which have efficacy in patients but suffer from deleterious side effects (notably liver fibrosis, and pancreatic hyperplasia). Another approach would be to lower glucagon secretion from the alpha-cell directly via pharmaceutical intervention, but to date, no such Docket No.: 020153/WO active compound has been developed. Type 1 diabetes (T1D) is typically characterized by severe insulin deficiency and is widespread in both pediatric and adult populations. Individuals with T1D require injection of insulin, an unstable peptide, to treat hyper- glycemia and prevent death. The drawbacks of insulin treatment include invasive administration along with associated risks of hypoglycemia and weight gain. Alternatives to insulin-only therapy could improve the quality of life for people with T1D. Destruction of pancreatic β cells as T1D progresses not only brings about glucose intolerance but also disrupts the normal glucagon response of α cells to hypoglycemia. The loss of β cells leads to abnormal behavior of α cells, causing glucagon hypersecretion that exacerbates hyperglycemia through stimulation of gluconeogenesis and glycogenolysis. Accordingly, a glucagon-centric hypothesis proposes that combating hyperglucagonemia can lead to the normalization of hyperglycemia in T1D. Targeting hyperglucagonemia as a complementary therapeutic tactic for insulin treatment in T1D has resulted in several treatment strategies, including brown adipose tissue transplantation and the use of glucagon receptor antagonists, antibodies, or chemical compounds. Among these approaches, treatment with glucagon receptor–competitive or allosteric antagonists in clinical trials has been plagued by side effects, including α cell hyperplasia that exacerbates hyperglucagonemia and yields recurring hyperglycemia, hyperlipidemia, elevation of plasma transaminases, and weight gain. Based on these observations, researchers explored suppression of glucagon secretion as a possible strategy for treating hyperglycemia in T1D. Flow-sorting α cells or dispersing islets into single cells mimics the α cell T1D phenotype, where glucagon secretion increases as a function of glucose. Reaggregation of α and β cells into pseudo-islets results in suppression of glucagon secretion, suggesting that physical contact between α and β cells may play a role in regulating glucagon secretion. EphrinA-EphA signaling is one mechanism that has been shown to mediate cell-cell contacts in the islet, with erythropoietin-producing human hepatocellular receptor type-A4 (EphA4) playing a central role in the α cell. The misregulation of glucagon secretion from dispersed α cells is accompanied by reduced F-actin intensity. Treating dispersed α cells with soluble Ephrin-A5 (a natural ligand of EphA4 receptors) restored normal F-actin intensity and glucagon secretion profiles. These findings suggest the presence of an axis between the Ephrin-A5-EphA4 complex and F-actin in α cells toward the regulation of glucagon secretion. In T1D when there is a lack of β cells in islets, this Docket No.: 020153/WO axis is compromised, which results in glucagon hypersecretion. SUMMARY OF THE INVENTION Among the various aspects of the present disclosure is the provision of compositions and methods of use of small molecule agonists of EphA receptors to treat diabetes. Briefly, therefore, the present disclosure is directed to EphA agonists and related methods to treat diabetes using the administration of the disclosed EphA agonists. In one aspect, an EphA family agonist is disclosed that includes a structure as given by Structure (I): (I), wherein COOCH3, COOC2H5, COOC3H7, or COOC4H9; R2 comprises OH, COOCH3, COOC2H5, COOC3H7, or COOC4H9; R3 comprises NH2, NH+, or NH2COCH3; and R4 comprises OH, COOCH3, COOC2H5, COOC3H7, or COOC4H9. In some aspects, the EphA family agonist of claim 1 includes the structure as given by Structure (II):

Docket No.: 020153/WO wherein: R5 comprises CH3, C2H5, C3H7, or C4H9; R6 comprises CH3, C2H5, or C3H7; and R7 comprises H2, CH3, or C2H5. In some aspects, the EphA family agonist includes the structure as given by Structure (III): (III), H2, CH3, or C2H5; and, R10 comprises H2, CH3, or C2H5. In some aspects, the EphA family agonist includes a structure selected from: or

Docket No.: 020153/WO In some aspects, the EphA family agonist includes an EphA4 agonist. In some aspects, the EphA family agonist lowers glucagon levels in a diabetic patient. In some aspects, the EphA family agonist normalizes blood sugar in the diabetic patient. In another aspect, a composition for the treatment of a diabetic patient in need is disclosed that includes a therapeutically effective amount of an EphA family agonist, wherein the EphA family agonist comprises a structure as given by Structure (I): (I), COOCH3, COOC2H5, COOC3H7, or COOC4H9; R2 comprises OH, COOCH3, COOC2H5, COOC3H7, or COOC4H9; R3 comprises NH2, NH+, or NH2COCH3; and R4 comprises OH, COOCH3, COOC2H5, COOC3H7, or COOC4H9. In some aspects, the composition includes an EphA family agonist with a structure as given by Structure (II): (II), wherein: R5 comprises CH3, C2H5, C3H7, or C4H9; R6 comprises CH3, C2H5, or C3H7; and R7 comprises H2, CH3, or C2H5. In some aspects, the composition includes an EphA family agonist with a structure as given by Structure (III): Docket No.: 020153/WO , wherein R8 and, R10 comprises H2, CH3, or C2H5. In some aspects, the composition includes an EphA family agonist with a structure selected from: or In some aspects, the EphA family agonist of the composition comprises an EphA4 agonist. In some aspects, the EphA family agonist of the composition lowers glucagon levels in a diabetic patient. In some aspects, the EphA family agonist of the composition Docket No.: 020153/WO normalizes blood sugar in the diabetic patient. In some aspects, the composition further includes Estman BioSustane SAIB NF, Agar, and L(-)Malic acid formulated in a pearl for oral administration. In some aspects, the EphA family agonist of the composition blocks EphA4 receptors in alpha-cells. In another aspect, a method of treating a diabetic patient in need is disclosed that includes administering a therapeutically effective amount of an EphA family agonist. The EphA family agonist comprises a structure as given by: (I), Wherein COOCH3, COOC2H5, COOC3H7, or COOC4H9; R2 comprises OH, COOCH3, COOC2H5, COOC3H7, or COOC4H9; R3 comprises NH2, NH+, or NH2COCH3; and R4 comprises OH, COOCH3, COOC2H5, COOC3H7, or COOC4H9. In some aspects, the EphA family agonist comprises the structure given by Structure II: (II), wherein R5 comprises CH3, C2H5, C3H7, or C4H9; R6 comprises CH3, C2H5, or C3H7; and R7 comprises H2, CH3, or C2H5. In some aspects, the EphA family agonist comprises the structure given by Docket No.: 020153/WO Structure III: (III), H2, CH3, or C2H5; and, R10 comprises H2, CH3, or C2H5. In some aspects, the EphA family agonist comprises a structure selected from: or pointed out hereinafter. Docket No.: 020153/WO DESCRIPTION OF THE DRAWINGS Those of skill in the art will understand that the drawings, described below, are for illustrative purposes only. The drawings are not intended to limit the scope of the present teachings in any way. FIG.1A is an image of the structural formula of WCDD301, an EphA agonist. FIG.1B is a graph determining the binding affinity of WCDD301 for EphA4 without global fitting. FIG.1C is a graph determining the binding affinity of WCDD301 for EphA4 via data normalization, non-linear regression, and the Cheng-Prusoff equation. FIG.1D is a graph demonstrating competition between WCDD301 and a range of Ephrin-A5 Fc concentrations for binding to a fixed level of EphA4 in the ELISA system via area under curve (AUC) analysis; *** indicates a difference between each concentration of Ephrin-A5 Fc with the previous one at p<0.001. FIG.1E is a graph demonstrating competition between WCDD301 and Ephrin-A5 Fc for binding to a fixed level of EphA4; experiments were designed based on Michaleis- Menten kinetics; *p<0.05, **p<0.01, ***p<0.001 compared to the 0μM WCDD301. FIG.1F is a graph quantifying the secretion of glucagon in murine dispersed islet cells in the presence and absence of WCDD301; ***p<0.001 compared to the control. FIG.1G is a graph quantifying the secretion of insulin in murine dispersed islet cells in the presence and absence of WCDD301; ***p<0.001 compared to the control. FIG.1H is a graph quantifying secretion of glucagon in murine dispersed islet cells following co-treatment of WCDD301 with an EphA4 antagonist, Rhyncophylline; ***p<0.001, ns (not significant) compared to the control. FIG.2A is a graph quantifying glucagon secretion from healthy human dispersed islet cells following 1h exposure to WCDD301. FIG.2B is a graph quantifying glucagon secretion from healthy human dispersed islet cells following 3h exposure to WCDD301. FIG.2C is a graph quantifying glucagon secretion from healthy human dispersed islet cells following 6h exposure to WCDD301. Docket No.: 020153/WO FIG.2D is a graph quantifying insulin secretion from healthy human dispersed islet cells following 1h exposure to WCDD301. FIG.2E is a graph quantifying insulin secretion from healthy human dispersed islet cells following 3h exposure to WCDD301. FIG.2F is a graph quantifying insulin secretion from healthy human dispersed islet cells following 6h exposure to WCDD301. FIG.2G is a graph quantifying the secretion of glucagon in isolated islets of T1D subjects. FIG.2H is a graph quantifying the secretion of glucagon in dispersed islet cells of T1D subjects. FIG. 2I is a graph quantifying the secretion of insulin in isolated islets of T1D subjects. FIG.2J is a graph quantifying the secretion of insulin in dispersed islet cells of T1D subjects. FIG.2K is a set of immunostained images of healthy human dispersed islet cells for F-actin and glucagon in non-treated (C), and treated cells with WCDD301 (301) or Ephrin-A5 Fc (EFN). FIG.2L is a graph of the comparison of F-actin intensity among C, 301, and EFN groups in the images in FIG.2K. FIG.2M is a set of immunostained images of healthy human dispersed islet cells for EphA4 and glucagon in non-treated (C), and treated cells with WCDD301 (301) or Ephrin-A5 Fc (EFN). FIG.2N is a graph of the comparison of EphA4 intensity among C, 301, and EFN groups. On the scatter plot, each dot represents values (Mean± SD) for one mouse. *p<0.05, **p<0.01, ***p<0.001; 1-Way ANOVA compared to the respective control. FIG.2O is a set of immunostained images of healthy mouse dispersed islet cells for F-actin and glucagon in non-treated (C), and treated cells with WCDD301 (301) or Ephrin-A5 Fc (EFN). FIG.2P is a graph of the comparison of F-actin intensity among C, 301, and EFN groups in the images in FIG.2O. On the scatter plot, each dot represents values (Mean± Docket No.: 020153/WO SD) for one mouse. *p<0.05, **p<0.01, ***p<0.001; 1-Way ANOVA compared to the respective control. FIG.2Q is a set of immunostained images of healthy mouse dispersed islet cells for EphA4 and glucagon in non-treated (C), and treated cells with WCDD301 (301) or Ephrin-A5 Fc (EFN). FIG.2R is a graph of the comparison of EphA4 intensity among C, 301, and EFN groups. On the scatter plot, each dot represents values (Mean± SD) for one mouse. *p<0.05, **p<0.01, ***p<0.001; 1-Way ANOVA compared to the respective control. FIG.3A is a graph of the stability of WCDD301 in mouse plasma. Half-life: T_1/2. FIG.3B is a graph of the stability of a positive control compound (Propantheline) in mouse plasma. Half-life: T1/2. FIG.3C is a graph of the stability of WCDD301 in human plasma. Half-life: T1/2. FIG.3D is a graph of the stability of Propantheline in human plasma. Half-life: T_1/2. FIG.3E is a graph of the stability of WCDD301 in mouse liver microsomes. Half- life: T1/2; Intrinsic clearance: CLint(mic); Hepatic clearance: CLint(liver). FIG.3F is a graph of the stability of Diclofenac in mouse liver microsomes. Half- life: T_1/2; Intrinsic clearance:CL_int(mic); Hepatic clearance: CL_int(liver). FIG.3G is a graph of the stability of Propafenone in mouse liver microsomes. Half- life: T1/2; Intrinsic clearance:CLint(mic); Hepatic clearance: CLint(liver). FIG.3H is a graph of the stability of Testosterone in mouse liver microsomes. Half- life: T_1/2; Intrinsic clearance:CL_int(mic); Hepatic clearance: CL_int(liver). FIG.3I is a graph of the stability of WCDD301 in human liver microsomes. Half- life: T1/2; Intrinsic clearance: CLint(mic); Hepatic clearance: CLint(liver). FIG.3J is a graph of the stability of Diclofenac in human liver microsomes. Half- life: T1/2; Intrinsic clearance: CLint(mic); Hepatic clearance: CLint(liver). FIG.3K is a graph of the stability of Propafenone in human liver microsomes. Half- life: T_1/2; Intrinsic clearance: CL_int(mic); Hepatic clearance: CL_int(liver). FIG.3L is a graph of the stability of Testosterone in human liver microsomes. Half- life: T1/2; Intrinsic clearance: CLint(mic); Hepatic clearance: CLint(liver). Docket No.: 020153/WO FIG.4A is a graph from an experiment treating diabetic NOD mice at an early stage of T1D (non-fasting blood glucose: 200-250 mg/dL) with WCDD301 (oral, 7.5 mg/kg) formulated in SAIB-Agar excipient and monitoring blood glucose over 11 weeks. ***p<0.001; 1-Way ANOVA. FIG.4B is a graph from an experiment treating diabetic NOD mice at a higher stage of T1D (non-fasting blood glucose: 250-350 mg/dL) with WCDD301 (oral, a single dose of 15 mg/kg, continued by 7.5 mg/kg) formulated in SAIB-Agar-Malic excipient and monitoring blood glucose over 4 weeks. ***p<0.001; 1-Way ANOVA. FIG. 4C is a graph of plasma glucagon concentration following treatment of the higher stage in T1D NOD mice. ***p<0.001; 1-Way ANOVA. FIG.4D is a graph of plasma insulin concentration following treatment of the higher stage in T1D NOD mice. FIG.4E is a graph of intraperitoneal glucose tolerance curves following treatment of the higher stage T1D in NOD mice. FIG.4F is a graph from an experiment treating STZ-induced diabetic mice (non- fasting blood glucose: 250-300 mg/dL) with WCDD301 (oral, a single dose of 15 mg/kg, continued by 7.5 mg/kg) formulated in SAIB-Agar-Malic excipient and monitoring blood glucose over 4 weeks. ***p<0.001; 1-Way ANOVA. FIG.5A is a graph of insulin secretion in dispersed murine islet cells in the presence of an EphA4 inhibitor (Rhyncophylline) with or without WCDD301. FIG. 5B is a graph of the binding of Ephrin-A5 and alkaline phosphatase- conjugated anti-Ephrin-A5 antibodies in the presence and absence of WCDD301. FIG.6A is a graph of somatostatin secretion in healthy human dispersed islet cells following 1h incubation with WCDD301. FIG.6B is a graph of somatostatin secretion in healthy human dispersed islet cells following 3h incubation with WCDD301. FIG.6C is a graph of somatostatin secretion in healthy human dispersed islet cells following 6h incubation with WCDD301. FIG.6D is a graph of somatostatin secretion in response to WCDD301 (301) and Ephrin-A5 Fc (E) in isolated islets from T1D subjects. Docket No.: 020153/WO FIG.6E is a graph of the shedding of EphA4 into medium in murine dispersed cells, cultured in 111mM glucose with Ephri-A5 Fc or WCDD301 or without (C).*p<0.01; 1-Way ANOVA. FIG. 7A is a graph quantifying blood glucose levels in an experiment wherein WCDD301 dosing is stopped in treated diabetic NOD mice and resumed 48h later.*p<0.05, ***p<0.001; 1-Way ANOVA or t-test. FIG.7B is a graph quantifying glucagon levels in pancreata of non-diabetic (ND), diabetic (D), and 4-week treated diabetic NOD mice with WCDD301. *p<0.05, ***p<0.001; 1-Way ANOVA or t-test. FIG. 7C is a graph quantifying insulin levels in pancreata of non-diabetic (ND), diabetic (D), and 4-week treated diabetic NOD mice with WCDD301. *p<0.05, ***p<0.001; 1-Way ANOVA or t-test. FIG. 7D is a graph quantifying non-fasting blood glucose levels in non-diabetic normoglycemic NOD mice treated with WCDD301 between the ages of 10 to 19 weeks. *p<0.05, ***p<0.001; 1-Way ANOVA or t-test. FIG.8A is a photo of the clinical manifestations of Placebo-treated diabetic NOD mice following 4 weeks of dosing. FIG.8B is a photo of the clinical manifestations of WCDD301-treated diabetic NOD mice following 4 weeks of dosing. FIG.9 is a schematic describing the absorption of WCDD301 along the alimentary tract, wherein the highest absorption occurs in the ileal region. FIG.10 is a schematic describing the stability of WCDD301 in biological conditions. The long stability leads to a long-lasting effect. FIG. 11 is a schematic of an F-actin network pathway. WCDD301 targets the EphA4/F-actin axis, intensifies the F-actin network, suppresses glucagon secretion, and makes its effect through the EphA4 in α-cells of T1D. FIG.12A is a set of immunostained images of dispersed murine islet cells (a model for T1D) after pre-incubation with 11 mM KRBH (1h), followed by treatment with 20 µM WCDD301 in 1mM glucose for 1 hr. The images show that WCDD301 intensifies cortical F-actin in murine dispersed α-cells. Docket No.: 020153/WO FIG.12B is a set of immunostained images of dispersed murine islet cells (a model for T1D) after pre-incubation with 11 mM KRBH (1h), followed by treatment with 20 µM WCDD301 in 11mM glucose for 1 hr. The images show that WCDD301 intensifies cortical F-actin in murine dispersed α-cells. FIG.13A is a set of immunostained images of dispersed human islet cells (a model for T1D) after pre-incubation with 11 mM KRBH (1h), followed by treatment with 20 µM WCDD301 in 1mM glucose for 1 hr. The images show that WCDD301 intensifies cortical F-actin in human dispersed α-cells. FIG.13B is a set of immunostained images of dispersed human islet cells (a model for T1D) after pre-incubation with 11 mM KRBH (1h), followed by treatment with 20 µM WCDD301 in 11mM glucose for 1 hr. The images show that WCDD301 intensifies cortical F-actin in human dispersed α-cells. FIG. 14A is a graph quantifying glucagon secretion from mouse α-cells after treatment with control, Fc-ephrin-A5, or WCDD301 (1 mM or 11 mM glucose) for 1 hr. The graph shows that WCDD301 suppresses glucagon secretion in murine dispersed α-cells. FIG. 14B is a graph quantifying glucagon secretion from human α-cells after treatment with control, Fc-ephrin-A5, or WCDD301 (1 mM or 11 mM glucose) for 1 hr. The graph shows that WCDD301 suppresses glucagon secretion in human dispersed α-cells. FIG. 15 is a graph quantifying glucagon secretion from mouse α-cells after pre- treatment with 12.5 µM DPHBA (which blocks EphA4 receptor) for 30 min, followed by continued incubation with or without WCDD301 in the sequential order glucose concentration order (1 to 11 mM or 11 to 1 mM). The graph shows that blocking EphA4 in α-cells abolishes the suppressive effect of WCDD301 on glucagon secretion. FIG.16 is a schematic describing the potential ways in which WCDD301 interacts with EphA4. FIG. 17A is a schematic showing that γ-esterase cleaves EphA4 at different sequences within the intramembrane segment or extracellular domain. FIG. 17B is a schematic of receptor tyrosine kinase function, trafficking, and degradation, which includes cleavages by γ-esterase. FIG. 18 is a graph quantifying glucagon secretion from mouse α-cells after pre- treatment with 25 µM DAPT (which inhibits γ-esterase) for 30 min, followed by continued Docket No.: 020153/WO incubation with or without WCDD301 in the sequential order of glucose concentration (1 to 11 mM or 11 to 1 mM control). The graph shows that inhibition of γ-esterase abolishes the suppressive effect of WCDD301 on glucagon secretion in dispersed murine α-cells. FIG.19A is a set of immunostained images of dispersed murine islet cells (a model for T1D) after pre-incubation with 11 mM KRBH (1h), followed by treatment with WCDD301 in 1mM glucose for 1 hr. The images show that WCDD301 increases the intracellular intensity of EphA4 in murine dispersed α-cells. FIG.19B is a set of immunostained images of dispersed murine islet cells (a model for T1D) after pre-incubation with 11 mM KRBH (1h), followed by treatment with WCDD301 in 11 mM glucose for 1 hr. The images show that WCDD301 increases the intracellular intensity of EphA4 in murine dispersed α-cells. FIG.20A is a set of immunostained images of dispersed human islet cells (a model for T1D) after pre-incubation with 11 mM KRBH (1h), followed by treatment with WCDD301 in 1mM glucose for 1 hr. The images show that WCDD301 increases the intracellular intensity of EphA4 in human dispersed α-cells. FIG.20B is a set of immunostained images of dispersed human islet cells (a model for T1D) after pre-incubation with 11 mM KRBH (1h), followed by treatment with WCDD301 in 11 mM glucose for 1 hr. The images show that WCDD301 increases the intracellular intensity of EphA4 in human dispersed α-cells. FIG.21A is a graph quantifying insulin secretion in dispersed murine α-cells after incubation with ephrin-A5 (E) or WCDD301 (C=untreated control) in 1 mM glucose for 1 hr, followed by incubation with 11 mM glucose for 1 hr. The graph shows that the suppressive effect of WCDD301 on glucagon secretion in murine α-cells is independent of insulin. FIG.21B is a graph quantifying somatostatin secretion in dispersed murine α-cells after incubation with ephrin-A5 (E) or WCDD301 (C=untreated control) for 1 hr, followed by incubation with 11 mM glucose for 1 hr. The graph shows that the suppressive effect of WCDD301 on glucagon secretion in murine α-cells is independent of insulin. FIG.22A is a graph quantifying insulin secretion in dispersed human α-cells after incubation with ephrin-A5 (E) or WCDD301 (C=untreated control) in 1 mM glucose for 1 hr, followed by incubation with 11 mM glucose for 1 hr. The graph shows that the Docket No.: 020153/WO suppressive effect of WCDD301 on glucagon secretion in human α-cells is independent of insulin. FIG.22B is a graph quantifying somatostatin secretion in dispersed human α-cells after incubation with ephrin-A5 (E) or WCDD301 (C=untreated control) in 1 mM glucose for 1 hr, followed by incubation with 11 mM glucose for 1 hr. The graph shows that the suppressive effect of WCDD301 on glucagon secretion in human α-cells is independent of insulin. FIG.23A is a graph of blood glucose over time in healthy and STZ-induced diabetic mice treated with 10 mg/kg WCDD301 once a day. FIG.23B is a graph of blood glucose over time in healthy and STZ-induced diabetic mice treated with 10 mg/kg WCDD301 twice a day. FIG.23C is a graph of blood glucose over time in healthy and STZ-induced diabetic mice treated with 10 mg/kg WCDD301 three times a day. FIG.24 is a graph of blood glucose over time in NOD diabetic mice treated with 10 mg/kg WCDD301 once a day. FIG.25A is a graph of blood glucose over time in untreated STZ-induced diabetic mice, STZ-induced diabetic mice treated with WCDD301, and healthy control mice. FIG.25B is a graph of blood glucose over time in untreated and WCDD301-treated NOD diabetic mice. FIG.26A is a schematic of the chemical structure of WCDD302, an EphA agonist. FIG.26B is a graph quantifying glucagon secretion in mouse dispersed islet cells after incubation with WCDD302. FIG. 26C is a graph quantifying blood glucose levels in untreated db/db mice, WCDD302-treated mice, and healthy control mice. FIG.26D is a graph quantifying plasma glucagon levels in untreated db/db mice, WCDD302-treated mice, and healthy control mice. FIG. 26E is a graph quantifying plasma insulin levels in untreated db/db mice, WCDD302-treated mice, and healthy control mice. FIG. 27A is a set of stained pancreatic intact islets in db/db mice treated with WCDD302. Docket No.: 020153/WO FIG.27B is a graph of glucagon (GCG) and insulin (INS) levels per cell in untreated and WCDD302-treated db/db mice quantified from the stained images in FIG.27A. FIG.28A is a set of images of untreated human islets (T2D) stained with glucagon (GLG, green) and EphA4 (red). Cells were incubated with 1 mM stain. FIG.28B is a set of images of untreated human islets (T2D) stained with glucagon (GLG, green) and EphA4 (red). Cells were incubated with 11 mM stain. FIG.28C is a set of images of WCDD302-treated human islets (T2D) stained with glucagon (GLG, green) and EphA4 (red). Cells were incubated with 1 mM stain. FIG.28D is a set of images of WCDD302-treated human islets (T2D) stained with glucagon (GLG, green) and EphA4 (red). Cells were incubated with 11 mM stain. FIG.29 is a schematic diagram of a reaction that modifies WCDD302 to WCDD315 and WCDD316. FIG. 30A is a schematic diagram of the dispersion and washing steps of the procedure to create the β-cell ablated dispersed islet cell model. FIG.30B is a schematic diagram of the ablation, clean-up, and α-cell proliferation potential steps of the procedure to create the β-cell ablated dispersed islet cell model. FIG. 31A is a graph quantifying glucagon secretion as a function of glucose concentration, which shows a linear correlation. FIG. 31B is a graph quantifying insulin secretion as a function of glucose concentration. FIG. 31C is a graph quantifying somatostatin (SST) secretion as a function of glucose concentration. FIG.32A is a graph quantifying insulin secretion in the β-cell ablated dispersed islet cell model. FIG.32B is a set of cell images from the β-cell ablated dispersed islet cell model stained for glucagon (GCG), insulin (INS), and somatostatin (SST). These dual-positive cells are functional. FIG.33A is a set of murine cell images from the β-cell ablated dispersed islet cell model stained for glucagon (GCG), insulin (INS), and somatostatin (SST), which show single cell pseudo-islet formation. Docket No.: 020153/WO FIG.33B set of murine cell images from the β-cell ablated dispersed islet cell model stained for glucagon (GCG), insulin (INS), and somatostatin (SST), which show single- cell pseudo-islet formation. FIG.34A is a graph quantifying glucagon (GCG) secretion from a single mouse cell pseudo-islet treated with 1 and 11 mM glucose solutions. FIG.34B is a graph quantifying insulin secretion from a single mouse cell pseudo- islet treated with 1 and 11 mM glucose solutions. FIG. 34C is a graph quantifying somatostatin secretion from a single mouse cell pseudo-islet treated with 1 and 11 mM glucose solutions. FIG. 34D is a graph quantifying glucagon (GCG) secretion from a single human cell pseudo-islet treated with 1 and 11 mM glucose solutions. FIG.34E is a graph quantifying insulin secretion from a single human cell pseudo- islet treated with 1 and 11 mM glucose solutions. FIG. 34F is a graph quantifying somatostatin secretion from a single human cell pseudo-islet treated with 1 and 11 mM glucose solutions. FIG.35A is a pair of images of transdifferentiated αRFP-cells on day 4. SCI=single cell pseudo-islet. FIG.35B is a pair of images of transdifferentiated αRFP-cells on day 6. SCI=single cell pseudo-islet. FIG. 36 contains a set of stained cell images showing that an α-cell transdifferentiates to functional single-cell pseudo-islets. FIG. 37 is a schematic of the underlying mechanism of transdifferentiation of a single α-cell to a single pseudo-islet. FIG. 38A is a schematic diagram of a first synthetic scheme to formulate WCDD301. FIG. 38B is a schematic diagram of a second synthetic scheme to formulate WCDD301. FIG. 39A is a diagram of the chemical structure of compound 1, tri-aceto-oxy aminomethane (WCDD301). Docket No.: 020153/WO FIG.39B is a diagram of the chemical structure of compound 1-1, a derivative of WCDD301 shown in FIG.39A. FIG.39C is a diagram of the chemical structure of compound 1-2, a derivative of WCDD301 shown in FIG.39A. FIG. 40 is a diagram of the chemical structure of Compound 2, tri-propano-oxy aminomethane. FIG.41 is a diagram of the chemical structure of Compound 2-2 (a derivative of WCDD302 named WCDD315), tri-propano-oxy aminomethane. FIG.42 is a diagram of the chemical structure of Compound 2-3 (a derivative of WCDD302 named WCDD316), tri-propano-oxy aminomethane. FIG.43A is a diagram of the chemical structure of Compound 2-Special (named WCDD150), tri-propano-oxy aminomethane. FIG.43B is a diagram of the chemical structure of Compound 2-4 (a derivative of WCDD150). FIG.43C is a diagram of the chemical structure of Compound 2-5 (a derivative of WCDD150). FIG. 44 is a diagram of the chemical structure of Compound 3, tri-propano-oxy amino methane. FIG. 45 is a diagram of the chemical structure of Compound 4, tri-butyro-oxy aminomethane. FIG.46 is a diagram of the chemical structure of Compound 5, 1,2,3 aceto-oxy 2- iminoacetyl propane, of the present disclosure; Compound 5 was used as a control compound in the examples described herein to confirm the role that a free NH₂ enhances the agonistic properties of the EphA agonist compounds described herein. FIG.47 is a diagram of the chemical structure of Compound 6. FIG.48 is a diagram of the chemical structure of Compound 7. FIG. 49 is a diagram of the chemical structure of Compound 8, 1-aceto-oxy 2 amino, 2-hydroxymethyl propanol. FIG.50 is a diagram of the chemical structure of Compound 9, 1 and 3 di-aceto- Docket No.: 020153/WO oxy 2 amino, 2-hydroxymethyl propane. FIG.51 is a diagram of the chemical structure of Compound 10, 1 and 2 di-aceto- oxy 2 amino, 2-hydroxymethyl propane. FIG.52 is a diagram of the chemical structure of Compound 11. FIG.53 is a diagram of the chemical structure of Compound 12. FIG.54 is a diagram of the chemical structure of Compound 13. FIG.55 is a diagram of the chemical structure of Compound 14. FIG.56 is a diagram of the chemical structure of Compound 15. FIG.57 is a diagram of the chemical structure of Compound 16. FIG.58 is a diagram of the chemical structure of Compound 17. FIG.59 is a diagram of the chemical structure of Compound 18. FIG.60 is a diagram of the chemical structure of Compound 19. FIG.61 is a diagram of the chemical structure of Compound 20. FIG.62 is a diagram of the chemical structure of Compound 21. FIG.63 is a diagram of the chemical structure of Compound 22. FIG.64 is a diagram of the chemical structure of Compound 23. FIG.65 is a diagram of the chemical structure of Compound 24. FIG.66 is a diagram of the chemical structure of Compound 25. FIG.67 is a diagram of the chemical structure of Compound 26. FIG.68 is a diagram of the chemical structure of Compound 27. FIG.69 is a diagram of the chemical structure of Compound 28. FIG.70 is a diagram of the chemical structure of Compound 29. FIG.71 is a diagram of the chemical structure of Compound 30. FIG.72 is a diagram of the chemical structure of Compound 31. FIG.73 is a diagram of the chemical structure of Compound 32. FIG.74 is a diagram of the chemical structure of Compound 33. Docket No.: 020153/WO FIG.75 is a diagram of the chemical structure of Compound 34. FIG.76 is a diagram of the chemical structure of Compound 35. FIG.77 is a diagram of the chemical structure of Compound 36. FIG.78 is a diagram of the chemical structure of Compound 37. FIG.79 is a diagram of the chemical structure of Compound 38. FIG.80A is a graph of WCDD0150 binding affinity for the EphA4 receptor. FIG. 80B is a graph of an MTT cytotoxicity assay in HepG2 cells depicting the proliferation of HepG2 with increasing concentrations of WCDD0150, demonstrating that WCDD0150 is a safe compound for therapeutic applications. FIG. 80C is a graph quantifying glucagon secretion from dispersed α-cells given 1mM or 11mM of glucose and exposed to control, EFN, or WCDD0150. FIG.80D is a graph quantifying blood glucose levels in STZ-induced diabetic mice treated with placebo or WCDD0150 (2.5 mg/kg) once daily over the course of 9 weeks. FIG.80E is a graph quantifying blood glucose levels in diabetic NOD mice treated with placebo or WCDD0150 (2.5 mg/kg) once daily over the course of 9 weeks. FIG. 80F is a graph quantifying plasma glucagon levels in diabetic NOD mice treated with a placebo or WCDD0150. FIG.80G is a graph quantifying plasma insulin levels in diabetic NOD mice treated with a placebo or WCDD0150. FIG.80H is a graph of an insulin tolerance test depicting normalized blood glucose levels over time in diabetic NOD mice treated with a placebo or WCDD0150. FIG. 80I is a graph quantifying blood glucose levels over time in non-diabetic placebo-treated mice, diabetic placebo-treated mice, and WCDD0150-treated mice 8h after dosing. FIG.80J is a graph quantifying blood glucose levels normalized with basal glucose in non-diabetic placebo-treated mice, diabetic placebo-treated mice, and WCDD0150- treated mice. FIG. 81A is a graph quantifying plasma pharmacokinetics of CD-1 mice treated with WCDD0150 (1mg/kg) at various timepoints demonstrating plasma stability. Docket No.: 020153/WO FIG.81B is a graph quantifying the body weight ratio of the initial weight of diabetic NOD mice treated with a placebo or WCDD0150. FIG.81C is a graph quantifying food intake (g/KG BW/day) in diabetic NOD mice treated with a placebo or WCDD0150. FIG.81D is a graph quantifying urine glucose (mg/dL) of diabetic NOD mice treated with a placebo or WCDD0150. FIG.81E is a graph quantifying the body weight ratio of the initial weight of STZ- induced diabetic mice treated with a placebo or WCDD0150. FIG.81F is a graph quantifying food intake (g/KG BW/day) in STZ-induced diabetic mice treated with a placebo or WCDD0150. FIG. 81G is a graph quantifying urine glucose (mg/dL) of STZ-induced diabetic mice treated with placebo or WCDD0150. FIG.82 is a schematic depicting WCDD301 treated diabetic mice have normalized glucagon levels through binding of the EphA4 receptor on islet α-cells. FIG.83A is a hematoxylin-eosin image of pancreatic islets in diabetic mice. FIG. 83B is a set of immunostained images of dispersed islet cells for glucagon (GCG), F-actin, and EphA4 in diabetic mice. FIG.83C is a hematoxylin-eosin image of pancreatic islets in non-diabetic mice. FIG. 83D is a set of immunostained images of dispersed islet cells for glucagon (GCG), F-actin, and EphA4 in non-diabetic mice. FIG. 83E 83C is a hematoxylin-eosin image of pancreatic islets in WCDD301- treated mice. FIG. 83F is a set of immunostained images of dispersed islet cells for glucagon (GCG), F-actin, and EphA4 in WCDD301-treated mice. FIG. 83G is a graph quantifying the F-actin intensity in α-cells of nondiabetic, diabetic, and WCDD301-treated mice. FIG. 83H is a graph quantifying the EphA4 intensity in α-cells of nondiabetic, diabetic, and WCDD301-treated mice. FIG.84A is a graph quantifying the stability of WCDD301 in human pooled plasma Docket No.: 020153/WO compared to the positive control propantheline. FIG.84B is a graph quantifying the stability of WCDD301 in mouse pooled plasma compared to the positive control propantheline. FIG. 84C is a graph quantifying the stability of WCDD301 in human hepatic microsomes compared to the positive controls diclofenac, testosterone, and propafenone. FIG. 84D is a graph quantifying the stability of WCDD301 in mouse hepatic microsomes compared to the positive controls diclofenac, testosterone, and propafenone. FIG.85A is a graph quantifying blood glucose levels (mg/dL) in diabetic NOD mice with moderate hyperglycemia using a placebo or WCDD301 (7.5mg/kg, oral administration) over 11 weeks. Values (mean ± SEM) in each week were compared with the values before treatment (week 1) using 1-way ANOVA. **p<0.01, ***p<0.001. FIG. 85B is a graph quantifying plasma glucagon (pg/mL) following treatment of the NOD mice (ND – nondiabetic, D – diabetic, WCDD301-treated). One-way ANOVA; ***p<0.001, n=5. FIG.85C is a graph quantifying plasma insulin (ng/mL) following treatment of the NOD mice (ND – nondiabetic, D – diabetic, WCDD301-treated). One-way ANOVA; ***p<0.001, n=5. FIG. 85D is a graph quantifying blood glucose (mg/dL) in non-diabetic placebo- treated, diabetic placebo-treated, and diabetic WCDD301 treated (8hr, 14hr, and 24hr after WCDD301 dosing). Values expressed as mean ± SEM (n=3) and areas under the curves compared among groups using 1-way ANOVA. ***p<0.001 compared with the nondiabetic placebo-treated mice. FIG.85E is a graph of insulin tolerance quantifying blood glucose normalized with basal glucose in NOD mice (diabetic placebo dosed, diabetic WCDD301 dosed, non- diabetic placebo dosed). Values expressed as mean ± SEM (n=4) and areas under the curves compared among groups using 1-way ANOVA. ***p<0.001 compared with the diabetic placebo-treated or diabetic ECDD301-treated mice. FIG. 85F is a graph quantifying blood glucose (mg/dL) in STZ-induced diabetic mice with early severe hyperglycemia treated with placebo (n=3) or WCDD301 (10mg/kg, n=4) and monitored over the course of 4 weeks. Values in each week were compared with the corresponding values before dosing using 1-way ANOVA; ***p<0.001. Docket No.: 020153/WO FIG.85G is a graph quantifying glucose output (pmol/ug cell protein) from primary mouse hepatocytes in the presence or absence of 100 nM glucagon and/or 3 µM WCDD301 (n=5). Each dot represents the mean values of 1 mouse. Values of WCDD301- treated groups compared with the corresponding control using the t-test. FIG.86A is a graph quantifying plasma levels of GLP-1 (pM) in ND (nondiabetic placebo-treated), D (diabetic placebo), and 301 (diabetic WCDD301-treated) NOD mice. Values were compared using 1-way ANOVA (n=4). FIG.86B is a graph quantifying plasma levels of glutamine (mM) in ND (nondiabetic placebo-treated), D (diabetic placebo), and 301 (diabetic WCDD301-treated) NOD mice. Values were compared using 1-way ANOVA (n=4). FIG.86C is a graph quantifying is a graph quantifying plasma levels of somatostatin (pg/mL) in ND (nondiabetic placebo-treated), D (diabetic placebo), and 301 (diabetic WCDD301-treated) NOD mice. Values were compared using 1-way ANOVA (n=4). FIG.86D is a graph quantifying daily urine glucose (mg/dL) in nondiabetic placebo- treated, diabetic placebo-treated, and diabetic WCDD301-treated NOD mice. Values (n=4, mean ± SEM) of diabetic placebo-treated mice compared with the other groups; 1- way ANOVA, α=0.05. *p<0.05, **p<0.01, ***p<0.001. FIG. 86E is a graph quantifying daily food intake (g/Kg BW/day) in nondiabetic placebo-treated, diabetic placebo-treated, and diabetic WCDD301-treated NOD mice. Values (n=4, mean ± SEM) of diabetic placebo-treated mice compared with the other groups; 1-way ANOVA, α=0.05. *p<0.05, **p<0.01, ***p<0.001. FIG. 86F is a graph quantifying daily body weight (g) in nondiabetic placebo- treated, diabetic placebo-treated, and diabetic WCDD301-treated NOD mice. Values (n=4, mean ± SEM) of diabetic placebo-treated mice compared with the other groups; 1- way ANOVA, α=0.05. *p<0.05, **p<0.01, ***p<0.001. FIG. 87A is a graph quantifying glucagon secretion from human dispersed islet cells exposed to 1 mM or 11 mM of glucose and following treatment with Doxazosin (0 µM, 10 µM, 100 µM, 200 µM). Values (n=3, mean ± SEM) were compared to the 0 µM control; 1-way ANOVA; **p<0.01, ***p<0.001. FIG. 87B is a graph quantifying glucagon secretion from mouse dispersed islet cells exposed to 1 mM or 11 mM of glucose and following treatment with Doxazosin (0 Docket No.: 020153/WO µM, 10 µM, 100 µM, 200 µM). Values (n=3, mean ± SEM) were compared to the 0 µM control; 1-way ANOVA; **p<0.01, ***p<0.001. FIG. 87C is a graph quantifying glucagon secretion from mouse dispersed islet cells following treatment with a conjugate of Doxazosin with lysine (Doxazosin-Lys) at concentrations 0 µM, 10 µM, 100 µM, and 200 µM. Values (n=3, mean ± SEM) were compared to the 0 µM control; 1-way ANOVA; **p<0.01, ***p<0.001. FIG. 87D is a graph quantifying glucagon secretion from mouse dispersed islet cells following treatment with a conjugate of Doxazosin with tyrosine (Doxazosin-Tyr) at concentrations 0 µM, 10 µM, 100 µM, and 200 µM. Values (n=3, mean ± SEM) were compared to the 0 µM control; 1-way ANOVA; **p<0.01, ***p<0.001. FIG. 87E is a graph quantifying glucagon secretion from mouse dispersed islet cells following treatment with a conjugate of Doxazosin with proline (Doxazosin-Pro) at concentrations 0 µM, 10 µM, 100 µM, and 200 µM. Values (n=3, mean ± SEM) were compared to the 0 µM control; 1-way ANOVA; **p<0.01, ***p<0.001. FIG.88 is a graph quantifying glucagon secretion in murine dispersed islet cells in response to control (C), Arginine (Arg; 25 mM), WCDD301 (301; 3 µM), Ephrin-A5 (E; 4ug/mL), Arginine plus WCDD301 (Arg + 301), and Arginine plus Ephrine-A5 (Arg + E). Values of each group (n=5, mean ± SEM) compared to the Arginine stimulated group (Arg); 1-way ANOVA. **p<0.01, ***p<0.001. FIG.89 is a graph quantifying insulin secretion in dispersed murine islet cells in the presence and absence of EphA4 inhibitor (Rhy: Rhyncophylline), WCDD301 (301), or Ephrin-A5 Fc (E). Each dot represents values for one mouse. Values of each group (n=5, mean± SEM) compared to the respective control; 1-Way ANOA; ns (not significant). FIG. 90A is a graph quantifying somatostatin secretion (pg/mL) in non-diabetic human donor dispersed islet cells following 1h incubation with WCDD301. Each dot represents mean values for dispersed islet cells of one subject or mouse. Values (n=3, mean ± SEM) compared to the respective controls;1-Way ANOVA. *p<0.05; ns (not significant). FIG. 90B is a graph quantifying somatostatin secretion (pg/mL) in non-diabetic human donor dispersed islet cells following 3h incubation with WCDD301. Each dot represents mean values for dispersed islet cells of one subject or mouse. Values (n=3, Docket No.: 020153/WO mean ± SEM) compared to the respective controls;1-Way ANOVA. *p<0.05; ns (not significant). FIG. 90C is a graph quantifying somatostatin secretion (pg/mL) in non-diabetic human donor dispersed islet cells following 6h incubation with WCDD301. Each dot represents mean values for dispersed islet cells of one subject or mouse. Values (n=3, mean ± SEM) compared to the respective controls;1-Way ANOVA. *p<0.05; ns (not significant). FIG.90D is a graph quantifying EphA4 (ng/ug cell glucagon) shed from dispersed mouse islet cells into the culture medium of vehicle-treated (C) and treated groups with Ephrin-A5 Fc and WCDD301(301). Each dot represents mean values for dispersed islet cells of one subject or mouse. Values (n=3, mean ± SEM) compared to the respective controls;1-Way ANOVA. *p<0.05; ns (not significant). FIG. 91A is a graph quantifying the plasma survival rate of WCDD301 injected subcutaneously (1mg/kg) in mice (n=3) at 5, 10, and 15 minutes post-dosing. FIG. 91B is a graph quantifying the plasma survival rate of WCDD301 injected intravenously (1mg/kg) in mice (n=3) at 5, 10, and 15 minutes post-dosing. FIG.92A is a graph quantifying blood glucose (mg/dL) diabetic NOD mice before treatment, during WCDD301 treatment, after stopping treatment, and after resuming WCDD301 treatment. Comparison of values (n=3, mean ± SEM) was performed using unpaired t-test ***p<0.001. FIG.92B is a graph quantifying blood glucose (mg/dL) in NOD mice at the age of 10 weeks and 19 weeks under placebo-treated (n=6) and WCDD301-treated (n=5) conditions. FIG.93A is a graph quantifying the number of α-cells through mean islet glucagon intensity in ND (nondiabetic placebo-treated), D (diabetic placebo), and 301 (diabetic WCDD301-treated) following 11 weeks of administration of WCDD301 or placebo. FIG. 93B is a graph quantifying the size of α-cells in ND (nondiabetic placebo- treated), D (diabetic placebo), and 301 (diabetic WCDD301-treated) following 11 weeks of administration of WCDD301 or placebo. FIG.94 is a schematic diagram of the one-step synthesis of the chemical structure WCDD301 from the initial compound of tris (hydroxymethyl) aminomethane hydrochloride Docket No.: 020153/WO in the presence of Acetic anhydride (Ac2O) and Acetic acid (HOAc). FIG.95 is a schematic diagram of the three-step synthesis of the chemical structure WCDD301 which has a high product output. Chemical reaction for scale-up synthesis of WCDD301 following amine protection of the tris (hydroxymethyl) aminomethane hydrochloride using tert-Butyloxy carbonyl (Boc) and continuation of reactions in the presence of Acetyl chloride (AcCl), Triethylamine (TEA), Dichloromethane (DCM) and Trifluoroacetic acid (TFA). FIG.96A is a diagram of compound WCDD151. FIG.96B is a diagram of a first derivative of compound WCDD151. FIG.96C is a diagram of a second derivative of compound WCDD151. DETAILED DESCRIPTION OF THE INVENTION The present disclosure is based, at least in part, on the discovery that alpha-cell EphA4 receptors in healthy individuals are stimulated by beta-cell ephrin ligands, and that these interactions play a key role in suppressing glucagon. This control is lost during diabetes when the beta-cells fail (Type 2 diabetes) or are destroyed by autoimmunity (Type 1 diabetes). As shown herein, a series of small molecules have been constructed that were designed to target the EphA4 receptor. Three promising lead compounds have been identified, one of which appears specific for EphA4, and one that might target other EphA family members as well. The first compound WCDD301 blocks EphA4 receptors in mouse and human alpha-cells with action similar to soluble ephrin, and can be competed away with a known EphA receptor agonist, DPHBA. WCDD301 lowers glucagon, but also insulin from healthy pancreatic islets. It is also shown that oral administration of the compound can normalize blood glucose in mouse models of diabetes. A second compound, WCDD315, is also expected to have efficacy based on studies of its parent compound. Initial animal experiments show that it may be more effective for type 2 diabetes, as it appears to lower glucagon and raise insulin in vivo. In some aspects, scaling up the production of the compounds allows detailed in vivo studies. A third compound, WCDD0150, has a high affinity for the EphA4 receptor. Animal experiments demonstrate that WCDD0150 can lower glucagon and blood glucose levels in diabetic mice. One aspect of the present disclosure provides for compositions that can normalize Docket No.: 020153/WO blood glucose to treat diabetes. EPHA4 MODULATION AGENTS As described herein, EphA4 expression has been implicated in various diseases, disorders, and conditions. As such, modulation of EphA4 (e.g., modulation of the EphA4 receptor) can be used for the treatment of such conditions. An EphA4 modulation agent can modulate EphA4 response or induce or inhibit EphA4. EphA4 modulation can comprise modulating the expression of EphA4 on cells, modulating the quantity of cells that express EphA4, or modulating the quality of the EphA4-expressing cells. EphA4 modulation agents can be any composition or method that can modulate EphA4 expression on cells (e.g., WCDD301). For example, an EphA4 modulation agent can be an activator, an inhibitor, an agonist, or an antagonist. As another example, the EphA4 modulation can be the result of gene editing. An EphA4 modulation agent can be an anti-EphA4 antibody (e.g., a monoclonal antibody to EphA4). An EphA4 modulating agent can be an agent that induces or inhibits progenitor cell differentiation into EpHA4-expressing cells. For example, WCDD301 can be used to block EphA4.   EphA4 Signal Increase, Creation, or Enhancement by Small Molecule Agonists, shRNA, siRNA, or ASOs As described herein, an EphA4 modulation agent can be used in diabetes therapy. An EphA4 modulation agent can be used to reduce/eliminate or enhance/increase EphA4 signals. For example, an EphA4 modulation agent can be a small molecule inhibitor or agonist of EphA4. As another example, an EphA4 modulation agent can be a short hairpin RNA (shRNA). As another example, an EphA4 modulation agent can be a short interfering RNA (siRNA). As another example, RNA (e.g., long noncoding RNA (lncRNA)) can be targeted with antisense oligonucleotides (ASOs) as a therapeutic. Processes for making ASOs targeted to RNAs are well known; see e.g. Zhou et al.2016 Methods Mol Biol.1402:199- 213. Except as otherwise noted herein, therefore, the process of the present disclosure can be carried out in accordance with such processes. Docket No.: 020153/WO EPHA4 AGONIZING AGENT One aspect of the present disclosure provides for targeting of EphA4, its receptor, or its downstream signaling. The present disclosure provides methods of treating or preventing diabetes based on the discovery that WCDD301 agonizes EphA4 signaling, resulting in reduced hypersecretion of glucagon and normalized blood glucose in mouse models. As described herein, agonists of EphA4 (e.g., antibodies, fusion proteins, small molecules) can reduce or prevent diabetes. An EphA4 agonizing agent can be any agent that can enhance EphA4 signaling, upregulate EphA4 signaling, or knock-in EphA4 signaling. In broader embodiments, the compositions described herein, which include small molecules, can target and agonize signaling by the receptors of any EphA family member. In some embodiments, the agonist can be WCDD301, WCDD302, WCDD315, or any of the other compounds as described herein. As an example, an EphA4 agonizing agent can enhance EphA4 signaling. As another example, the EphA4 agonizing agent can be an anti-EphA4 receptor antibody, wherein the anti-EphA4 receptor antibody prevents binding of the ligand to the EphA4 receptor, and/or induces activation of EphA4 signaling. As another example, an EphA4 agonizing agent can be WCDD301, which has been shown to be a potent and specific agonist of EphA4 signaling. As another example, an EphA4 agonizing agent can be an excitatory protein that agonizes EphA4 signaling. For example, the EphA4 agonizing agent can be a viral protein, which has been shown to agonize EphA4 signaling. As another example, an EphA4 agonizing agent can be a short hairpin RNA (shRNA) or a short interfering RNA (siRNA) targeting EphA4 receptors. As another example, an EphA4 agonizing agent can be a sgRNA targeting the EphA4 receptor. CHEMICAL AGENT: Examples of EphA agonizing agents, including but not limited to EphA4 receptor agonizing agents, are described herein. EphA receptor agonizing agents can be WCDD301, of the formula C10H17NO6 (MW = 247.11 g/mol), shown in FIG. 1A. EphA Docket No.: 020153/WO agonizing agents can also be WCDD302, of the formula shown in FIG.26A, or WCDD315. In some aspects, the EphA4 receptor agonizing agents may include compounds with a structure given by Structure I: (I), OH, COOCH₃, COOC₂H₅, COOC₃H₇, or COOC₄H₉; R₂ comprises OH, COOCH3, COOC2H5, COOC3H7, or COOC4H9; R3 comprises NH2, NH⁺, or NH₂COCH₃; and R4 comprises OH, COOCH₃, COOC₂H₅, COOC₃H₇, or COOC₄H₉. Various non-limiting examples of Structure I compounds are provided in Table I below: TABLE 1: Structure I EphA4 receptor agonizing agents Compound No. R1 R2 R3 R4 FIGURE 1 (WCDD301) COOCH3 COOCH3 NH2 COOCH3 39A 1-2 NH2 COOCH3 NH2 COOCH3 39B 1-3 NH2 COOCH3 NH+ COOCH3 39C 2 (WCDD302) COOC2H5 COOC2H5 NH2 COOC2H5 40 2-2 (WCDD315) COOC2H5 OH NH2 COOC2H5 41 2-3 (WCDD316) OH OH NH2 COOC2H5 42 2-Special (WCDD150) COOCH3 COOC2H5 NH2 COOC2H5 43A 2-4 NH2 COOC2H5 NH2 COOC2H5 43B 2-5 NH2 COOC2H5 NH+ C2H5 43C 3 COOC3H7 COOC3H7 NH2 COOC3H7 44 4 COOC4H9 COOC4H9 NH2 COOC4H9 45 5 COOCH3 COOCH3 NH2COCH3 COOCH3 46 8 OH COOCH3 NH2 OH 49 9 OH COOCH3 NH2 COOCH3 50 10 COOCH3 OH NH2 COOCH3 51 11 COOC2H5 COOCH3 NH2 COOCH3 52 12 COOCH3 COOC2H5 NH2 COOC2H5 53 Docket No.: 020153/WO 13 COOC3H7 COOCH3 NH2 COOCH3 54 14 COOCH3 COOC3H7 NH2 COOC3H7 55 15 COOC4H9 COOCH3 NH2 COOCH3 56 16 COOCH3 COOC4H9 NH2 COOC4H9 57 17 COOC4H9 COOC4H9 NH2 COOC4H9 58 18 COOC2H5 COOC4H9 NH2 COOC4H9 59 19 COOC3H7 COOC4H9 NH2 COOC4H9 60 20 COOC3H7 COOC3H7 NH2 COOC3H7 61 21 COOC2H5 COOC3H7 NH2 COOC3H7 62 22 COOC4H9 COOC3H7 NH2 COOC3H7 63 In other aspects, the EphA4 receptor agonizing agents may include compounds with a structure given by Structure II:  (II), CH₃, C₂H₅, or C₃H₇; and R7 comprises H2, CH3, or C2H5. Various non-limiting examples of Structure II compounds are provided in Table 2 below: TABLE 2: Structure II EphA4 receptor agonizing agents Compound R5 R6 R7 Figure 6 CH3 CH3 H2 47 23 C4H9 C3H7 C2H5 64 25 C4H9 C3H7 CH3 66 27 C3H7 C3H7 C2H5 68 29 C2H5 C3H7 CH3 70 31 CH3 C3H7 C2H5 72 33 CH3 C3H7 CH3 74 35 C2H5 C2H5 CH3 76 37 C2H5 C2H5 H2 78 Docket No.: 020153/WO In other additional aspects, the EphA4 receptor agonizing agents may include compounds with a structure given by Structure III: CH3, or C2H5; and R10 comprises H2, CH3, or C2H5. Various non-limiting examples of Structure III compounds are provided in Table 2 below: TABLE 3: Structure III EphA4 receptor agonizing agents Compound R8 R9 R10 FIG 7 CH3 H2 H2 48 24 C4H9 C2H5 C2H5 65 26 C4H9 CH3 CH3 67 28 C3H7 C2H5 C2H5 69 30 C2H5 CH3 CH3 71 32 CH3 C2H5 C2H5 73 34 CH3 CH3 CH3 75 36 C2H5 CH3 CH3 77 38 C2H5 H2 H2 79 In other additional aspects, the EphA4 receptor agonizing agents may include WCDD151 and derivative compounds, the structures of which are illustrated in FIGS.96A, 96B, and 96C. In various other aspects, the R groups of any of the above compounds can be optionally substituted with one or more groups independently selected from the group consisting of hydroxyl; C1-10alkyl hydroxyl; amine; C1-10carboxylic acid; C1-10carboxyl; straight chain or branched C_1-10alkyl, optionally containing unsaturation; a C_2-10cycloalkyl Docket No.: 020153/WO optionally containing unsaturation or one oxygen or nitrogen atom; straight chain or branched C1-10alkyl amine; heterocyclyl; heterocyclic amine; and aryl comprising a phenyl; heteroaryl containing from 1 to 4 N, O, or S atoms; unsubstituted phenyl ring; substituted phenyl ring; unsubstituted heterocyclyl; and substituted heterocyclyl, wherein the unsubstituted phenyl ring or substituted phenyl ring can be optionally substituted with one or more groups independently selected from the group consisting of hydroxyl; C1-10alkyl hydroxyl; amine; C_1-10carboxylic acid; C_1-10carboxyl; straight chain or branched C_1-10alkyl, optionally containing unsaturation; straight chain or branched C1-10alkyl amine, optionally containing unsaturation; a C_2-10cycloalkyl optionally containing unsaturation or one oxygen or nitrogen atom; straight chain or branched C1-10alkyl amine; heterocyclyl; heterocyclic amine; aryl comprising a phenyl; and heteroaryl containing from 1 to 4 N, O, or S atoms; and the unsubstituted heterocyclyl or substituted heterocyclyl can be optionally substituted with one or more groups independently selected from the group consisting of hydroxyl; C1-10alkyl hydroxyl; amine; C1-10carboxylic acid; C1-10carboxyl; straight chain or branched C_1-10alkyl, optionally containing unsaturation; straight chain or branched C1-10alkyl amine, optionally containing unsaturation; a C2-10cycloalkyl optionally containing unsaturation or one oxygen or nitrogen atom; heterocyclyl; straight chain or branched C1-10alkyl amine; heterocyclic amine; and aryl comprising a phenyl; and heteroaryl containing from 1 to 4 N, O, or S atoms. Any of the above can be further optionally substituted. The term “imine” or “imino”, as used herein, unless otherwise indicated, can include a functional group or chemical compound containing a carbon-nitrogen double bond. The expression “imino compound”, as used herein, unless otherwise indicated, refers to a compound that includes an “imine” or an “imino” group as defined herein. The “imine” or “imino” group can be optionally substituted. The term “hydroxyl”, as used herein, unless otherwise indicated, can include -OH. The “hydroxyl” can be optionally substituted. The terms “halogen” and “halo”, as used herein, unless otherwise indicated, include chlorine, chloro, Cl; fluorine, fluoro, F; bromine, bromo, Br; or iodine, iodo, or I. The term “acetamide”, as used herein, is an organic compound with the formula CH₃CONH₂. The “acetamide” can be optionally substituted. The term “aryl”, as used herein, unless otherwise indicated, includes a carbocyclic Docket No.: 020153/WO aromatic group. Examples of aryl groups include, but are not limited to, phenyl, benzyl, naphthyl, or anthracenyl. The “aryl” can be optionally substituted. The terms “amine” and “amino”, as used herein, unless otherwise indicated, include a functional group that contains a nitrogen atom with a lone pair of electrons and wherein one or more hydrogen atoms have been replaced by a substituent such as, but not limited to, an alkyl group or an aryl group. The “amine” or “amino” group can be optionally substituted. The term “alkyl”, as used herein, unless otherwise indicated, can include saturated monovalent hydrocarbon radicals having straight or branched moieties, such as but not limited to, methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl groups, etc. Representative straight-chain lower alkyl groups include, but are not limited to, -methyl, -ethyl, -n-propyl, -n-butyl, -n-pentyl, -n-hexyl, -n-heptyl and -n-octyl; while branched lower alkyl groups include, but are not limited to, -isopropyl, -sec-butyl, -isobutyl, -tert-butyl, -isopentyl, 2- methylbutyl, 2-methylpentyl, 3-methylpentyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 2,2- dimethylpentyl, 2,3-dimethylpentyl, 3,3-dimethylpentyl, 2,3,4-trimethylpentyl, 3- methylhexyl, 2,2-dimethylhexyl, 2,4-dimethylhexyl, 2,5-dimethylhexyl, 3,5-dimethylhexyl, 2,4-dimethylpentyl, 2-methylheptyl, 3-methylheptyl, unsaturated C_1-10 alkyls include, but are not limited to, -vinyl, -allyl, -1-butenyl, -2-butenyl, -isobutylenyl, -1-pentenyl, -2- pentenyl, -3-methyl-1-butenyl, -2-methyl-2-butenyl, -2,3-dimethyl-2-butenyl, 1-hexyl, 2- hexyl, 3-hexyl, -acetylenyl, -propynyl, -1-butynyl, -2-butynyl, -1-pentynyl, -2-pentynyl, or - 3-methyl-1 butynyl. An alkyl can be saturated, partially saturated, or unsaturated. The “alkyl” can be optionally substituted. The term “carboxyl”, as used herein, unless otherwise indicated, can include a functional group consisting of a carbon atom double bonded to an oxygen atom and single bonded to a hydroxyl group (-COOH). The “carboxyl” can be optionally substituted. The term “alkenyl”, as used herein, unless otherwise indicated, can include alkyl moieties having at least one carbon-carbon double bond wherein alkyl is as defined above and including E and Z isomers of said alkenyl moiety. An alkenyl can be partially saturated or unsaturated. The “alkenyl” can be optionally substituted. The term “alkynyl”, as used herein, unless otherwise indicated, can include alkyl moieties having at least one carbon-carbon triple bond wherein alkyl is as defined above. An alkynyl can be partially saturated or unsaturated. The “alkynyl” can be optionally Docket No.: 020153/WO substituted. The term “acyl”, as used herein, unless otherwise indicated, can include a functional group derived from an aliphatic carboxylic acid, by removal of the hydroxyl (– OH) group. The “acyl” can be optionally substituted. The term “alkoxyl”, as used herein, unless otherwise indicated, can include O-alkyl groups wherein alkyl is as defined above and O represents oxygen. Representative alkoxyl groups include, but are not limited to, -O-methyl, -O-ethyl, -O-n-propyl, -O-n-butyl, -O-n-pentyl, -O-n-hexyl, -O-n-heptyl, -O-n-octyl, -O-isopropyl, -O-sec-butyl, -O-isobutyl, - O-tert-butyl, -O-isopentyl, -O-2-methylbutyl, -O-2-methylpentyl, -O-3-methylpentyl, -O- 2,2-dimethylbutyl, -O-2,3-dimethylbutyl, -O-2,2-dimethylpentyl, -O-2,3-dimethylpentyl, -O- 3,3-dimethylpentyl, -O-2,3,4-trimethylpentyl, -O-3-methylhexyl, -O-2,2-dimethylhexyl, -O- 2,4-dimethylhexyl, -O-2,5-dimethylhexyl, -O-3,5-dimethylhexyl, -O-2,4dimethylpentyl, -O- 2-methylheptyl, -O-3-methylheptyl, -O-vinyl, -O-allyl, -O-1-butenyl, -O-2-butenyl, -O- isobutylenyl, -O-1-pentenyl, -O-2-pentenyl, -O-3-methyl-1-butenyl, -O-2-methyl-2- butenyl, -O-2,3-dimethyl-2-butenyl, -O-1-hexyl, -O-2-hexyl, -O-3-hexyl, -O-acetylenyl, -O- propynyl, -O-1-butynyl, -O-2-butynyl, -O-1-pentynyl, -O-2-pentynyl and -O-3-methyl-1- butynyl, -O-cyclopropyl, -O-cyclobutyl, -O-cyclopentyl, -O-cyclohexyl, -O-cycloheptyl, -O- cyclooctyl, -O-cyclononyl and -O-cyclodecyl, -O-CH2-cyclopropyl, -O-CH2-cyclobutyl, -O- CH₂-cyclopentyl, -O-CH₂-cyclohexyl, -O-CH₂-cycloheptyl, -O-CH₂-cyclooctyl, -O- CH₂- cyclononyl, -O-CH2-cyclodecyl, -O-(CH2)2-cyclopropyl, -O-(CH2)2-cyclobutyl, -O-(CH2)2- cyclopentyl, -O-(CH₂)₂-cyclohexyl, -O-(CH₂)₂-cycloheptyl, -O-(CH₂)₂-cyclooctyl, -O- (CH2)2-cyclononyl, or -O-(CH2)2-cyclodecyl. An alkoxyl can be saturated, partially saturated, or unsaturated. The “alkoxyl” can be optionally substituted. The term “cycloalkyl”, as used herein, unless otherwise indicated, can include an aromatic, non-aromatic, saturated, partially saturated, or unsaturated, monocyclic or fused, spiro or unfused bicyclic or tricyclic hydrocarbon referred to herein containing a total of from 1 to 10 carbon atoms (e.g., 1 or 2 carbon atoms if there are other heteroatoms in the ring), preferably 3 to 8 ring carbon atoms. Examples of cycloalkyls include, but are not limited to, C3-10 cycloalkyl groups include, but are not limited to, -cyclopropyl, - cyclobutyl, -cyclopentyl, -cyclopentadienyl, -cyclohexyl, -cyclohexenyl, -1,3- cyclohexadienyl, -1,4-cyclohexadienyl, -cycloheptyl, -1,3-cycloheptadienyl, -1,3,5- cycloheptatrienyl, -cyclooctyl, and -cyclooctadienyl. The term “cycloalkyl” also can include Docket No.: 020153/WO -lower alkyl-cycloalkyl, wherein lower alkyl and cycloalkyl are as defined herein. Examples of -lower alkyl-cycloalkyl groups include, but are not limited to, -CH2-cyclopropyl, -CH2- cyclobutyl, -CH₂-cyclopentyl, -CH₂-cyclopentadienyl, -CH₂-cyclohexyl, -CH₂-cycloheptyl, or -CH2-cyclooctyl. The “cycloalkyl” can be optionally substituted. A “cycloheteroalkyl”, as used herein, unless otherwise indicated, can include any of the above with a carbon substituted with a heteroatom (e.g., O, S, N). The term “heterocyclic” or “heteroaryl”, as used herein, unless otherwise indicated, can include an aromatic or non-aromatic cycloalkyl in which one to four of the ring carbon atoms are independently replaced with a heteroatom from the group consisting of O, S and N. Representative examples of a heterocycle include, but are not limited to, benzofuranyl, benzothiophene, indolyl, benzopyrazolyl, coumarinyl, isoquinolinyl, pyrrolyl, pyrrolidinyl, thiophenyl, furanyl, thiazolyl, imidazolyl, pyrazolyl, triazolyl, quinolinyl, pyrimidinyl, pyridinyl, pyridonyl, pyrazinyl, pyridazinyl, isothiazolyl, isoxazolyl, (1,4)- dioxane, (1,3)-dioxolane, 4,5-dihydro-1H-imidazolyl, or tetrazolyl. Heterocycles can be substituted or unsubstituted. Heterocycles can also be bonded at any ring atom (i.e., at any carbon atom or heteroatom of the heterocyclic ring). A heterocyclic can be saturated, partially saturated, or unsaturated. The “hetreocyclic” can be optionally substituted. The term “indole”, as used herein, is an aromatic heterocyclic organic compound with the formula C₈H₇N. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing pyrrole ring. The “indole” can be optionally substituted. The term “cyano”, as used herein, unless otherwise indicated, can include a -CN group. The “cyano” can be optionally substituted. The term “alcohol”, as used herein, unless otherwise indicated, can include a compound in which the hydroxyl functional group (-OH) is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms. The “alcohol” can be optionally substituted. The term “solvate” is intended to mean a solvate form of a specified compound that retains the effectiveness of such a compound. Examples of solvates include compounds of the invention in combination with, for example, water, isopropanol, ethanol, methanol, dimethylsulfoxide (DMSO), ethyl acetate, acetic acid, or ethanolamine. The term “mmol”, as used herein, is intended to mean millimole. The term “equiv”, Docket No.: 020153/WO as used herein, is intended to mean equivalent. The term “mL”, as used herein, is intended to mean milliliter. The term “g”, as used herein, is intended to mean gram. The term “kg”, as used herein, is intended to mean kilogram. The term “µg”, as used herein, is intended to mean micrograms. The term “h”, as used herein, is intended to mean hour. The term “min”, as used herein, is intended to mean minute. The term “M”, as used herein, is intended to mean molar. The term "µL", as used herein, is intended to mean microliter. The term “µM”, as used herein, is intended to mean micromolar. The term “nM”, as used herein, is intended to mean nanomolar. The term “N”, as used herein, is intended to mean normal. The term “amu”, as used herein, is intended to mean atomic mass unit. The term “°C”, as used herein, is intended to mean degree Celsius. The term “wt/wt”, as used herein, is intended to mean weight/weight. The term “v/v”, as used herein, is intended to mean volume/volume. The term “MS”, as used herein, is intended to mean mass spectroscopy. The term “HPLC”, as used herein, is intended to mean high performance liquid chromatography. The term “RT”, as used herein, is intended to mean room temperature. The term "e.g.", as used herein, is intended to mean example. The term “N/A”, as used herein, is intended to mean not tested. As used herein, the expression “pharmaceutically acceptable salt” refers to pharmaceutically acceptable organic or inorganic salts of a compound of the invention. Preferred salts include, but are not limited, to sulfate, citrate, acetate, oxalate, chloride, bromide, iodide, nitrate, bisulfate, phosphate, acid phosphate, isonicotinate, lactate, salicylate, acid citrate, tartrate, oleate, tannate, pantothenate, bitartrate, ascorbate, succinate, maleate, gentisinate, fumarate, gluconate, glucaronate, saccharate, formate, benzoate, glutamate, methanesulfonate, ethanesulfonate, benzenesulfonate, p- toluenesulfonate, or pamoate (i.e., 1,1'-methylene-bis-(2-hydroxy-3-naphthoate)) salts. A pharmaceutically acceptable salt may involve the inclusion of another molecule such as an acetate ion, a succinate ion, or other counterions. The counterion may be any organic or inorganic moiety that stabilizes the charge on the parent compound. Furthermore, a pharmaceutically acceptable salt may have more than one charged atom in its structure. Instances, where multiple charged atoms are part of the pharmaceutically acceptable salt, can have multiple counterions. Hence, a pharmaceutically acceptable salt can have one or more charged atoms and/or one or more counterion. As used herein, the expression “pharmaceutically acceptable solvate” refers to an association of one or more solvent molecules and a compound of the invention. Examples of solvents that form Docket No.: 020153/WO pharmaceutically acceptable solvates include, but are not limited to, water, isopropanol, ethanol, methanol, DMSO, ethyl acetate, acetic acid, and ethanolamine. As used herein, the expression “pharmaceutically acceptable hydrate” refers to a compound of the invention, or a salt thereof, that further can include a stoichiometric or non-stoichiometric amount of water bound by non-covalent intermolecular forces. FORMULATION The agents and compositions described herein can be formulated by any conventional manner using one or more pharmaceutically acceptable carriers or excipients as described in, for example, Remington’s Pharmaceutical Sciences (A.R. Gennaro, Ed.), 21st edition, ISBN: 0781746736 (2005), incorporated herein by reference in its entirety. Such formulations will contain a therapeutically effective amount of a biologically active agent described herein, which can be in purified form, together with a suitable amount of carrier so as to provide the form for proper administration to the subject. The term "formulation" refers to preparing a drug in a form suitable for administration to a subject, such as a human. Thus, a "formulation" can include pharmaceutically acceptable excipients, including diluents or carriers. The term "pharmaceutically acceptable" as used herein can describe substances or components that do not cause unacceptable losses of the pharmacological activity or unacceptable adverse side effects. Examples of pharmaceutically acceptable ingredients can be those having monographs in United States Pharmacopeia (USP 29) and National Formulary (NF 24), United States Pharmacopeial Convention, Inc, Rockville, Maryland, 2005 ("USP/NF"), or a more recent edition, and the components listed in the continuously updated Inactive Ingredient Search online database of the FDA. Other useful components that are not described in the USP/NF, etc. may also be used. The term “pharmaceutically acceptable excipient,” as used herein, can include any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic, or absorption-delaying agents. The use of such media and agents for pharmaceutically active substances is well known in the art (see generally Remington’s Pharmaceutical Sciences (A.R. Gennaro, Ed.), 21st edition, ISBN: 0781746736 (2005)). Except insofar as any conventional media or agent is incompatible with an active ingredient, its use in Docket No.: 020153/WO therapeutic compositions is contemplated. Supplementary active ingredients can also be incorporated into the compositions. A "stable" formulation or composition can refer to a composition having sufficient stability to allow storage at a convenient temperature, such as between about 0 ºC and about 60 ºC, for a commercially reasonable period of time, such as at least about one day, at least about one week, at least about one month, at least about three months, at least about six months, at least about one year, or at least about two years. The formulation should suit the mode of administration. The agents of use with the current disclosure can be formulated by known methods for administration to a subject using several routes which include, but are not limited to, parenteral, pulmonary, oral, topical, intradermal, intratumoral, intranasal, inhalation (e.g., in an aerosol), implanted, intramuscular, intraperitoneal, intravenous, intrathecal, intracranial, intracerebroventricular, subcutaneous, intranasal, epidural, intrathecal, ophthalmic, transdermal, buccal, and rectal. The individual agents may also be administered in combination with one or more additional agents or together with other biologically active or biologically inert agents. Such biologically active or inert agents may be in fluid or mechanical communication with the agent(s) or attached to the agent(s) by ionic, covalent, Van der Waals, hydrophobic, hydrophilic, or other physical forces. Controlled-release (or sustained-release) preparations may be formulated to extend the activity of the agent(s) and reduce the dosage frequency. Controlled-release preparations can also be used to affect the time of onset of action or other characteristics, such as blood levels of the agent, and consequently affect the occurrence of side effects. Controlled-release preparations may be designed to initially release an amount of an agent(s) that produces the desired therapeutic effect, and gradually and continually release other amounts of the agent to maintain the level of therapeutic effect over an extended period of time. In order to maintain a near-constant level of an agent in the body, the agent can be released from the dosage form at a rate that will replace the amount of the agent being metabolized or excreted from the body. The controlled release of an agent may be stimulated by various inducers, e.g., change in pH, change in temperature, enzymes, water, or other physiological conditions or molecules. Agents or compositions described herein can also be used in combination with other therapeutic modalities, as described further below. Thus, in addition to the therapies Docket No.: 020153/WO described herein, one may also provide to the subject other therapies known to be efficacious for the treatment of the disease, disorder, or condition. THERAPEUTIC METHODS Also provided is a process of treating, preventing, or reversing diabetes in a subject in need of administration of a therapeutically effective amount of an EphA agonizing agent, so as to normalize blood glucose. Methods described herein are generally performed on a subject in need thereof. A subject in need of the therapeutic methods described herein can be a subject having, diagnosed with, suspected of having, or at risk for developing diabetes. A determination of the need for treatment will typically be assessed by a history, physical exam, or diagnostic tests consistent with the disease or condition at issue. Diagnosis of the various conditions treatable by the methods described herein is within the skill of the art. The subject can be an animal subject, including a mammal, such as horses, cows, dogs, cats, sheep, pigs, mice, rats, monkeys, hamsters, guinea pigs, and humans or chickens. For example, the subject can be a human subject. Generally, a safe and effective amount of an EphA agonizing agent, which can include an EphA4 agonizing agent, is, for example, an amount that would cause the desired therapeutic effect in a subject while minimizing undesired side effects. In various embodiments, an effective amount of WCDD301 described herein can substantially agonize EphA4 to slow the progress of diabetes or limit the development of diabetes. According to the methods described herein, administration can be parenteral, pulmonary, oral, topical, intradermal, intramuscular, intraperitoneal, intravenous, intratumoral, intrathecal, intracranial, intracerebroventricular, subcutaneous, intranasal, epidural, ophthalmic, buccal, or rectal administration. When used in the treatments described herein, a therapeutically effective amount of an EphA agonizing agent can be employed in pure form or, where such forms exist, in pharmaceutically acceptable salt form and with or without a pharmaceutically acceptable excipient. For example, the compounds of the present disclosure can be administered, at a reasonable benefit/risk ratio applicable to any medical treatment, in a sufficient amount to treat diabetes by normalizing blood glucose. The amount of a composition described herein that can be combined with a Docket No.: 020153/WO pharmaceutically acceptable carrier to produce a single dosage form will vary depending upon the subject or host treated and the particular mode of administration. It will be appreciated by those skilled in the art that the unit content of agent contained in an individual dose of each dosage form need not in itself constitute a therapeutically effective amount, as the necessary therapeutically effective amount could be reached by administration of a number of individual doses. Toxicity and therapeutic efficacy of compositions described herein can be determined by standard pharmaceutical procedures in cell cultures or experimental animals for determining the LD50 (the dose lethal to 50% of the population) and the ED50, (the dose therapeutically effective in 50% of the population). The dose ratio between toxic and therapeutic effects is the therapeutic index that can be expressed as the ratio LD₅₀/ED₅₀, where larger therapeutic indices are generally understood in the art to be optimal. The specific therapeutically effective dose level for any particular subject will depend upon a variety of factors including the disorder being treated and the severity of the disorder; activity of the specific compound employed; the specific composition employed; the age, body weight, general health, sex and diet of the subject; the time of administration; the route of administration; the rate of excretion of the composition employed; the duration of the treatment; drugs used in combination or coincidental with the specific compound employed; and like factors well known in the medical arts (see e.g., Koda-Kimble et al. (2004) Applied Therapeutics: The Clinical Use of Drugs, Lippincott Williams & Wilkins, ISBN 0781748453; Winter (2003) Basic Clinical Pharmacokinetics, 4^th ed., Lippincott Williams & Wilkins, ISBN 0781741475; Sharqel (2004) Applied Biopharmaceutics & Pharmacokinetics, McGraw-Hill/Appleton & Lange, ISBN 0071375503). For example, it is well within the skill of the art to start doses of the composition at levels lower than those required to achieve the desired therapeutic effect and to gradually increase the dosage until the desired effect is achieved. If desired, the effective daily dose may be divided into multiple doses for purposes of administration. Consequently, single-dose compositions may contain such amounts or submultiples thereof to make up the daily dose. It will be understood, however, that the total daily usage of the compounds and compositions of the present disclosure will be decided by an attending physician within the scope of sound medical judgment. Docket No.: 020153/WO Again, each of the states, diseases, disorders, and conditions, described herein, as well as others, can benefit from compositions and methods described herein. Generally, treating a state, disease, disorder, or condition includes preventing, reversing, or delaying the appearance of clinical symptoms in a mammal that may be afflicted with or predisposed to the state, disease, disorder, or condition but does not yet experience or display clinical or subclinical symptoms thereof. Treating can also include inhibiting the state, disease, disorder, or condition, e.g., arresting or reducing the development of the disease or at least one clinical or subclinical symptom thereof. Furthermore, treating can include relieving the disease, e.g., causing regression of the state, disease, disorder, or condition or at least one of its clinical or subclinical symptoms. A benefit to a subject to be treated can be either statistically significant or at least perceptible to the subject or to a physician. Administration of an EphA agonizing agent can occur as a single event or over a time course of treatment. For example, an EphA agonizing agent can be administered daily, weekly, bi-weekly, or monthly. For treatment of acute conditions, the time course of treatment will usually be at least several days. Certain conditions could extend treatment from several days to several weeks. For example, treatment could extend over one week, two weeks, or three weeks. For more chronic conditions, treatment could extend from several weeks to several months or even a year or more. Treatment in accordance with the methods described herein can be performed prior to, concurrent with, or after conventional treatment modalities for diabetes. An EphA agonizing agent, including but not limited to an EphA4 agonizing agent, can be administered simultaneously or sequentially with another agent, such as an antibiotic, an anti-inflammatory, or another agent. For example, an EphA agonizing agent can be administered simultaneously with another agent, such as an antibiotic or an anti- inflammatory. Simultaneous administration can occur through the administration of separate compositions, each containing one or more of an EphA agonizing agent, an antibiotic, an anti-inflammatory, or another agent. Simultaneous administration can occur through the administration of one composition containing two or more of an EphA agonizing agent, an antibiotic, an anti-inflammatory, or another agent. An EphA agonizing agent can be administered sequentially with an antibiotic, an anti-inflammatory, or another agent. For example, an EphA4 agonizing agent can be administered before or after the Docket No.: 020153/WO administration of an antibiotic, an anti-inflammatory, or another agent. ADMINISTRATION Agents and compositions described herein can be administered according to methods described herein in a variety of means known to the art. The agents and composition can be used therapeutically either as exogenous materials or as endogenous materials. Exogenous agents are those produced or manufactured outside of the body and administered to the body. Endogenous agents are those produced or manufactured inside the body by some type of device (biologic or other) for delivery within or to other organs in the body. As discussed above, administration can be parenteral, pulmonary, oral, topical, intradermal, intratumoral, intranasal, inhalation (e.g., in an aerosol), implanted, intramuscular, intraperitoneal, intravenous, intrathecal, intracranial, intracerebroventricular, subcutaneous, intranasal, epidural, intrathecal, ophthalmic, transdermal, buccal, and rectal. Agents and compositions described herein can be administered in a variety of methods well-known in the arts. Administration can include, for example, methods involving oral ingestion, direct injection (e.g., systemic or stereotactic), implantation of cells engineered to secrete the factor of interest, drug-releasing biomaterials, polymer matrices, gels, permeable membranes, osmotic systems, multilayer coatings, microparticles, implantable matrix devices, mini-osmotic pumps, implantable pumps, injectable gels and hydrogels, liposomes, micelles (e.g., up to 30 µm), nanospheres (e.g., less than 1 µm), microspheres (e.g., 1-100 µm), reservoir devices, a combination of any of the above, or other suitable delivery vehicles to provide the desired release profile in varying proportions. Other methods of controlled-release delivery of agents or compositions will be known to the skilled artisan and are within the scope of the present disclosure. Delivery systems may include, for example, an infusion pump which may be used to administer the agent or composition in a manner similar to that used for delivering insulin or chemotherapy to specific organs or tumors. Typically, using such a system, an agent or composition can be administered in combination with a biodegradable, biocompatible polymeric implant that releases the agent over a controlled period of time Docket No.: 020153/WO at a selected site. Examples of polymeric materials include polyanhydrides, polyorthoesters, polyglycolic acid, polylactic acid, polyethylene vinyl acetate, and copolymers and combinations thereof. In addition, a controlled release system can be placed in proximity of a therapeutic target, thus requiring only a fraction of a systemic dosage. Agents can be encapsulated and administered in a variety of carrier delivery systems. Examples of carrier delivery systems include microspheres, hydrogels, polymeric implants, smart polymeric carriers, and liposomes (see generally, Uchegbu and Schatzlein, eds. (2006) Polymers in Drug Delivery, CRC, ISBN-10: 0849325331). Carrier- based systems for molecular or biomolecular agent delivery can: provide for intracellular delivery; tailor biomolecule/agent release rates; increase the proportion of biomolecule that reaches its site of action; improve the transport of the drug to its site of action; allow colocalized deposition with other agents or excipients; improve the stability of the agent in vivo; prolong the residence time of the agent at its site of action by reducing clearance; decrease the nonspecific delivery of the agent to nontarget tissues; decrease irritation caused by the agent; decrease toxicity due to high initial doses of the agent; alter the immunogenicity of the agent; decrease dosage frequency, improve the taste of the product; or improve the shelf life of the product. SCREENING Also provided are methods for screening. The subject methods find use in the screening of a variety of different candidate molecules (e.g., potentially therapeutic candidate molecules). Candidate substances for screening according to the methods described herein include, but are not limited to, fractions of tissues or cells, nucleic acids, polypeptides, siRNAs, antisense molecules, aptamers, ribozymes, triple helix compounds, antibodies, and small (e.g., less than about 2000 mw, or less than about 1000 mw, or less than about 800 mw) organic molecules or inorganic molecules including but not limited to salts or metals. Candidate molecules encompass numerous chemical classes, for example, organic molecules, such as small organic compounds having a molecular weight of more than 50 and less than about 2,500 Daltons. Candidate molecules can comprise functional groups necessary for structural interaction with proteins, particularly hydrogen bonding, Docket No.: 020153/WO and typically include at least an amine, carbonyl, hydroxyl, or carboxyl group, and usually at least two of the functional chemical groups. The candidate molecules can comprise cyclical carbon or heterocyclic structures and/or aromatic or polyaromatic structures substituted with one or more of the above functional groups. A candidate molecule can be a compound in a library database of compounds. One of skill in the art will be generally familiar with, for example, numerous databases for commercially available compounds for screening (see e.g., ZINC database, UCSF, with 2.7 million compounds over 12 distinct subsets of molecules; Irwin and Shoichet (2005) J Chem Inf Model 45, 177-182). One of skill in the art will also be familiar with a variety of search engines to identify commercial sources or desirable compounds and classes of compounds for further testing (see e.g., ZINC database; eMolecules.com; and electronic libraries of commercial compounds provided by vendors, for example, ChemBridge, Princeton BioMolecular, Ambinter SARL, Enamine, ASDI, Life Chemicals, etc.). Candidate molecules for screening according to the methods described herein include both lead-like compounds and drug-like compounds. A lead-like compound is generally understood to have a relatively smaller scaffold-like structure (e.g., molecular weight of about 150 to about 350 kD) with relatively fewer features (e.g., less than about 3 hydrogen donors and/or less than about 6 hydrogen acceptors; hydrophobicity character xlogP of about -2 to about 4). In contrast, a drug-like compound is generally understood to have a relatively larger scaffold (e.g., molecular weight of about 150 to about 500 kD) with relatively more numerous features (e.g., less than about 10 hydrogen acceptors and/or less than about 8 rotatable bonds; hydrophobicity character xlogP of less than about 5) (see e.g., Lipinski (2000) J. Pharm. Tox. Methods 44, 235-249). Initial screening can be performed with lead-like compounds. When designing a lead from spatial orientation data, it can be useful to understand that certain molecular structures are characterized as being “drug-like”. Such characterization can be based on a set of empirically recognized qualities derived by comparing similarities across the breadth of known drugs within the pharmacopeia. While it is not required for drugs to meet all, or even any, of these characterizations, it is far more likely for a drug candidate to meet with clinical success if it is drug-like. Several of these “drug-like” characteristics have been summarized into the four rules of Lipinski (generally known as the “rules of fives” because of the prevalence of the Docket No.: 020153/WO number 5 among them). While these rules generally relate to oral absorption and are used to predict the bioavailability of compounds during lead optimization, they can serve as effective guidelines for constructing a lead molecule during rational drug design efforts such as may be accomplished by using the methods of the present disclosure. The four “rules of five” state that a candidate drug-like compound should have at least three of the following characteristics: (i) weight less than 500 Daltons; (ii) a log of P less than 5; (iii) no more than 5 hydrogen bond donors (expressed as the sum of OH and NH groups); and (iv) no more than 10 hydrogen bond acceptors (the sum of N and O atoms). Also, drug-like molecules typically have a span (breadth) of between about 8Å to about 15Å. KITS Also provided are kits. Such kits can include an agent or composition described herein and, in certain embodiments, instructions for administration. Such kits can facilitate the performance of the methods described herein. When supplied as a kit, the different components of the composition can be packaged in separate containers and admixed immediately before use. Components include, but are not limited to an EphA agonizing agent, Estman BioSustane SAIB NF, Agar, and L(-)Malic acid. Such packaging of the components separately can, if desired, be presented in a pack or dispenser device which may contain one or more unit dosage forms containing the composition. The pack may, for example, comprise metal or plastic foil such as a blister pack. Such packaging of the components separately can also, in certain instances, permit long-term storage without losing the activity of the components. Kits may also include reagents in separate containers such as, for example, sterile water or saline to be added to a lyophilized active component packaged separately. For example, sealed glass ampules may contain a lyophilized component and in a separate ampule, sterile water, sterile saline each of which has been packaged under a neutral non-reacting gas, such as nitrogen. Ampules may consist of any suitable material, such as glass, organic polymers, such as polycarbonate, polystyrene, ceramic, metal or any other material typically employed to hold reagents. Other examples of suitable containers include bottles that may be fabricated from similar substances as ampules, and envelopes that may consist of foil-lined interiors, such as aluminum or an alloy. Other containers include test tubes, vials, flasks, bottles, syringes, and the like. Containers may have a Docket No.: 020153/WO sterile access port, such as a bottle having a stopper that can be pierced by a hypodermic injection needle. Other containers may have two compartments that are separated by a readily removable membrane that upon removal permits the components to mix. Removable membranes may be glass, plastic, rubber, and the like. In certain embodiments, kits can be supplied with instructional materials. Instructions may be printed on paper or other substrate, and/or may be supplied as an electronic-readable medium or video. Detailed instructions may not be physically associated with the kit; instead, a user may be directed to an Internet website specified by the manufacturer or distributor of the kit. A control sample or a reference sample as described herein can be a sample from a healthy subject. A reference value can be used in place of a control or reference sample, which was previously obtained from a healthy subject or a group of healthy subjects. A control sample or a reference sample can also be a sample with a known amount of a detectable compound or a spiked sample. Compositions and methods described herein utilizing molecular biology protocols can be according to a variety of standard techniques known to the art (see e.g., Sambrook and Russel (2006) Condensed Protocols from Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory Press, ISBN-10: 0879697717; Ausubel et al. (2002) Short Protocols in Molecular Biology, 5th ed., Current Protocols, ISBN-10: 0471250929; Sambrook and Russel (2001) Molecular Cloning: A Laboratory Manual, 3d ed., Cold Spring Harbor Laboratory Press, ISBN-10: 0879695773; Elhai, J. and Wolk, C. P.1988. Methods in Enzymology 167, 747-754; Studier (2005) Protein Expr Purif.41(1), 207–234; Gellissen, ed. (2005) Production of Recombinant Proteins: Novel Microbial and Eukaryotic Expression Systems, Wiley-VCH, ISBN-10: 3527310363; Baneyx (2004) Protein Expression Technologies, Taylor & Francis, ISBN-10: 0954523253). Definitions and methods described herein are provided to better define the present disclosure and to guide those of ordinary skill in the art in the practice of the present disclosure. Unless otherwise noted, terms are to be understood according to conventional usage by those of ordinary skill in the relevant art. In some embodiments, numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth, used to describe and claim certain embodiments of the present disclosure are to be understood as being modified in Docket No.: 020153/WO some instances by the term “about.” In some embodiments, the term “about” is used to indicate that a value includes the standard deviation of the mean for the device or method being employed to determine the value. In some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the present disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the present disclosure may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements. The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. The recitation of discrete values is understood to include ranges between each value. In some embodiments, the terms “a” and “an” and “the” and similar references used in the context of describing a particular embodiment (especially in the context of certain of the following claims) can be construed to cover both the singular and the plural, unless specifically noted otherwise. In some embodiments, the term “or” as used herein, including the claims, is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive. The terms “comprise,” “have” and “include” are open-ended linking verbs. Any forms or tenses of one or more of these verbs, such as “comprises,” “comprising,” “has,” “having,” “includes” and “including,” are also open-ended. For example, any method that “comprises,” “has” or “includes” one or more steps is not limited to possessing only those one or more steps and can also cover other unlisted steps. Similarly, any composition or device that “comprises,” “has” or “includes” one or more features is not limited to possessing only those one or more features and can cover other unlisted features. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any Docket No.: 020153/WO and all examples, or exemplary language (e.g., “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the present disclosure and does not pose a limitation on the scope of the present disclosure otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the present disclosure. Groupings of alternative elements or embodiments of the present disclosure disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims. All publications, patents, patent applications, and other references cited in this application are incorporated herein by reference in their entirety for all purposes to the same extent as if each individual publication, patent, patent application, or other reference was specifically and individually indicated to be incorporated by reference in its entirety for all purposes. Citation of a reference herein shall not be construed as an admission that such is prior art to the present disclosure. Having described the present disclosure in detail, it will be apparent that modifications, variations, and equivalent embodiments are possible without departing from the scope of the present disclosure defined in the appended claims. Furthermore, it should be appreciated that all examples in the present disclosure are provided as non- limiting examples. EXAMPLES The following non-limiting examples are provided to further illustrate the present disclosure. It should be appreciated by those of skill in the art that the techniques disclosed in the examples that follow represent approaches the inventors have found function well in the practice of the present disclosure and thus can be considered to constitute examples of modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific Docket No.: 020153/WO embodiments that are disclosed and still obtain a like or similar result without departing from the spirit and scope of the present disclosure. EXAMPLE 1 - ORAL DRUG FOR SUPPRESSION OF GLUCAGON HYPERSECRETION AND NORMALIZATION OF HYPERGLYCEMIA IN TYPE 1 DIABETES Abstract Treatment of hyperglycemia in patients with type 1 diabetes (T1D) depends on insulin, which is accompanied by a risk of hypoglycemia, weight gain, cardiovascular diseases, and metabolic syndrome and represents an unfavorable route of administration. To find a replacement for insulin, suppression of glucagon hypersecretion in T1D is being studied as a treatment for hyperglycemia. It is proposed that activation of the EphA4 receptor on α-cells reduces glucagon hypersecretion in T1D, which directed the development of an agonist for the EphA4 receptor in α-cells. By synthesis of a series of chemical compounds and biological testing, WCDD301, a small chemical molecule with a high affinity for the EphA4 receptor and strong metabolic stability in both human and mouse models, was discovered. Importantly, WCDD301 reduces glucagon secretion from healthy human donor dispersed islet cells and from both isolated islets and dispersed islet cells from T1D subjects, at levels comparable to the natural EphA4 ligand, Ephrin-A5. WCDD301 increases F-actin density in both human and mouse α-cells in a manner similar to Ephrin-A5. In diabetic NOD mice, oral administration of WCDD301 reduces plasma glucagon and normalizes blood glucose, which remains constant for >3 months. As well, in STZ-induced diabetic mice, oral dosing of WCDD301 substantially reduces blood glucose levels. Thus, these findings describe a new chemical molecule as an EphA4 agonist, which is available for oral administration to suppress hyperglucagonemia and normalize hyperglycemia in T1D mouse models. Introduction Type 1 diabetes (T1D) is a progressive and degenerative disease that is widespread in both young and adult populations worldwide. Injection of insulin is the current strategy for the treatment of hyperglycemia in T1D; however, the invasive way of administration coupled with the risk of hypoglycemia, weight gain, development of metabolic syndrome, and increased risk of cardiovascular diseases highly demands Docket No.: 020153/WO finding a replacement for insulin therapy. Based on the pathophysiology of T1D, the destruction of β-cells in pancreatic islets brings about peripheral glucose intolerance and makes α-cells unresponsive to hypoglycemia. Consequently, lack of control over α-cells brings about glucagon hypersecretion, which results in exacerbation of hyperglycemia through gluconeogenesis and glycogenolysis. Accordingly, the glucagonocentric hypothesis of hyperglycemia is proposed wherein combating hyperglucagonemia of diabetes can result in the normalization of hyperglycemia in T1D. To combat hyperglucagonemia as a replacement therapeutic tactic for insulin therapy in T1D, researchers have pursued several strategies. In some cases, researchers have focused on brown adipose tissue transplantation, blocking glucagon receptors on target organs using antagonists and antibodies, or combating hyperglucagonemia by using chemical compounds. Based on the current literature, all of these fields are ongoing active topics. Among these approaches, some glucagon receptor blockers were designed in the form of a competitive or allosteric antagonist, which reached phases of clinical trials. However, this approach has encountered severe challenges such as α-cell hyperplasia and consequently exacerbated hyperglucagonemia-hyperglycemia, increased risk of hypoglycemia, hyperlipidemia, elevation of plasma transaminases, and weight gain. Because of these major concerns, researchers proposed that suppression of glucagon secretion would be an appealing strategy for the treatment of hyperglycemia in T1D. The underlying mechanism of glucagon secretion and suppression needs elucidation, which is a puzzle in islet biology. Importantly, some researchers have shown that the dispersion of islets results in insulin mirroring the phenotype of α-cells to secrete more glucagon in response to higher levels of glucagon secretion. Interestingly, for this scenario, it has been shown that forming pseudo-islets of α and β-cells results in the suppression of glucagon secretion, and it is proposed that physical contact between α and β-cells is a major player in the regulation of glucagon secretion. Then, it has been shown that in dissociated α-cells, the EphA4 signaling pathway becomes compromised, and treating dispersed α-cells with an EphA4 agonist recovers glucagon hypersecretion. In the current study, a novel EphA4 Docket No.: 020153/WO agonist is developed to suppress glucagon hypersecretion and restore hyperglycemia in a type 1 diabetes mouse model. Materials and Methods Synthesis of WCDD301 Over the course of this study, we used two synthetic approaches for the development of [2-(acetoxymethyl)-2-aminopropane-1,3-diyl diacetate] called WCDD301. The first approach can be seen in FIG.38A. The initial compound, Tris(hydroxymethyl)aminomethane hydrochloride (500 mg, 3.2 mmol), was dissolved in a mixture of acetic anhydride (1.2 ml, 11.7 mmol): acetic acid (1.5 ml) and heated at 110°C for 5 h. The solvent was removed in vacuum and the residue was washed three times using ether. Then, the residue was recrystallized from ethanol- ether to yield in WCDD301 (53.5 mg; 6.2% yield, 100% purity). The second strategy can be seen in FIG.38B. As shown, compound 1 (5 g, 22.60 mmol, 1.90 mL, 1 eq) was dissolved in dichloromethane (DCM;50 mL), and then Triethanolamine (TEA; 9.15 g, 90.40 mmol, 12.58 mL, 4 eq) and acetyl chloride (AcCl; 5.32 g, 67.80 mmol, 4.84 mL, 3 eq) were dropwise-added into the solution at 0°C under N2. Then, the mixture was stirred at 20°C for 4 hr. When liquid chromatography-mass spectrometry (LC-MS) showed the completion of the reactions, the yielded mixture was filtered, and the filtrate was concentrated in vacuum. This yielded compound 2 (7.5 g, 21.6 mmol, 95.6% yield) with an appearance of a yellow oil. Then, trifluoroacetic acid (TFA; 20 mL) was added to a solution of compound 2 (7.5 g, 21.6 mmol, 1 eq) in DCM (60 mL). The mixture was stirred at 20°C for 2 hr. By determining the completion of the reaction through LC-MS, the mixture was concentrated in vacuum and the residue was purified by prep-HPLC to obtain WCDD301 (3g, 8.31 mmol, 56.2% yield, 100% purity). Establishing an ELISA system to measure binding of ephrin-A5 and EphA4 receptor Wells of the Protein A-coated microplate (Pierce protein A coated clear strip plates, Cat# 15132) were washed using 200 µL of binding buffer (10mM PBS supplemented by 0.01% Tween 20). Recombinant mouse EphA4 Fc chimera protein (R&D systems, Cat# 641-A4-200) was reconstituted in 1x PBS (Genesee, Cat# 25-507XB, pH 7.2±0.1), Docket No.: 020153/WO dispensed (100 μL) in each well and rocked on a belly dancer shaker (3h at room temperature; RT). Following 3x wash in the binding buffer, blocking was done using 5% BSA in 10mM PBS for 3h at RT. Then, by 5x washing, the reconstituted recombinant mouse Ephrin-A5 Fc (R&D systems, Cat# 7396-EA-050) was added (100 µL) into each well and rocked for 2.5h on the shaker (depending on the type of experiments, concentrations of Ephrin-A5 Fc differed as mentioned in the Results section). Then, by 7x washing using binding buffer, Alkaline phosphatase (ALP)-conjugated antibody against Ephrin-A5 was diluted (1: 1000) in the binding buffer, added to each well, and incubated overnight at 4°C. Conjugation of the Ephrin-A5 antibody (Abnova, Cat# H00001946-M02; 0.5 mg/mL; target sequence 114-203) was done using an Abcam conjugation kit (Abcam, Cat# ab102850) based on the manufacturer instruction. Then, by 7x wash, a p-nitrophenyl phosphate tablet (Sigma, Cat# N1891) was reconstituted in 5 mL of 10mM PBS and added to each well (100µL). Following 1h shaking on the shaker at dark, the reaction was stopped by adding 100 µL of 3N NaOH. Optical density (OD) was read at 405 nm within 5 min using the microplate reader (BioTek Cytation5 imaging reader). Determining binding affinity of WCDD301 for EphA4 receptor To determine the binding affinity (inhibition constant; ^^_^ ൌ ^{ூ^ఱబ} ^_{ା^ೄೠ್ೞ^^ೌ^^^} ) of WCDD301 ^_ಾ for EphA4, in the designed ELISA system, Ephrin-A5 Fc incubated in EphA4-coated wells in the presence or absence of WCDD301 (0.1 µM). As a control, the Fc fragment (Biolegend, Cat# 790102) was incubated and used for normalization of data. By running the experiment at a range of Ephrin-A5 Fc (2, 4, 8, 16, 32, 64 nM) Km(KD) values were determined in the absence (KM) and presence of WCDD301 (KM-obs). Then, Ki was determined via an approach called finding Ki without global fitting. This approach provided a Km value for WCDD301 and an estimate for its binding affinity, ki. To further confirm this finding, experiments were designed in the context of 8 nM ephrin-A5 to determine bound levels of ephrin-A5 in the presence of WCDD301 (0, 0.1, 0.4, 0.8, and 1.6 µM). Collected data were normalized and fitted by non-linear regression in GraphPad Prism Software to determine IC50. Then, using the Cheng-Prusoff equation ( ^^ ^{^ூ^^^^^௧^^^} ^ ൌ _^ಾ,^್ೞ ), the Ki value was determined. Determining competition between WCDD301 and ephrinA5 for binding to EphA4 receptor Docket No.: 020153/WO To show there is a competition between Ephrin-A5 and WCDD301 for binding to the EphA4 receptor, wells of the microplate were coated with a fixed level of EphA4 Fc (3.5 picomole/well), and then four sets of experiments in 96-well plates were designed. In addition, another approach was taken to further demonstrate competition between WCDD301 and Ephrin-A5 for binding to EphA4. To this end, in the EphA4-coated microplate (3.5 picomole/well), 4 sets of experiments were designed. Next, the KD value was determined for each condition utilizing Michaelis-Menten best-fit analysis in GraphPad Prism Software version 4. Meanwhile, as a control for potential interaction between WCDD301 and Ephrin-A5 Fc, wells of microplate were coated using Ephrin-A5 Fc and then incubated them with or without WCDD301(0.2 μM). Determining whether WCDD301 binds to the ligand binding domain (LBD) of the EphA4 receptor Pancreata of non-diabetic C57BL/6 mice were digested using reconstituted collagenase P (Roche Diagnostics GmbH, Germany, Cat# 11213873001) in modified HBSS solution (without calcium and magnesium), and islets were manually picked up using a stereomicroscope. Following an overnight resting in RPMI 1640 (Gibco, Cat# 11879-020) supplemented with 11 mM glucose, islets were dispersed. Briefly, 120 isolated islets were washed 2x using modified HBSS, and dispersed in 600 µL Accutase (Innovative Cell Technologies, Cat# AT-104) by gently pipetting up and down for 7 min at 37°C. Then, following neutralization of enzyme using RPMI 1640 supplemented with 10% FCS, cells were washed 2x using HBSS containing 11 mM glucose and rested in KRBH medium (115 mM NaCl; 4.7 mM KCl; 2.6 mM CaCl₂; 1.2 mM KH₂PO₄; 1.2 mM MgSO₄; 10mM HEPES; 2 mM Glutamine; 5 mM NaHCO3; 0.1% BSA; pH 7.4) containing 11 mM glucose for 1h. Following refreshing of KRBH, cells were dispensed in 8 microtubes (2000 cells/microtube) and treated with WCDD301, preclustered ephrin-A5 Fc, or preclustered Fc in the presence or absence of the competitive inhibitor of EphA4 receptor, Rhyncophylline (Sigma, Cat# SML2345). Preclustration was done through mixing Ephrin- A5 Fc or Fc alone (Biolegend, Cat# 790102) with an Anti-Fc antibody (Invitrogen, Cat# A16086) (1:10 molar ratio) 20 min before treatment. At the end of each experiment, glucagon secretion was measured (Promega, Lumit Immunoassay) and its reduction was considered as a reflective measure for the binding of WCDD301 with LBD of the EphA receptor. For measuring shed EphA4 in the cell culture medium, each experiment was Docket No.: 020153/WO performed by dispersion of 200 islets, and EphA4 levels in media were measured by EphA4 ELISA kit (ABclonal, Cat# RK06572; antibody targeting N-terminal of EphA4, amino acids 20-547). Treatment of healthy human dispersed islet cells with WCDD301 The Integrated Islet Distribution Program (IIDP) provided three batches of healthy human islets with the following characteristics. Sex Age BMI Ethnicity Male 16 29.5 Hispanic/Latino Male 34 25.8 White Male 28 27.8 Hispanic/Latino Following receiving and sedimentation (centrifugation at 500g for 3 min), islets were re-suspended in CMRL 1066 medium (Gibco, Cat# 1150-037) containing 11mM glucose and rested overnight in a cell culture incubator. Islets were dispersed as mentioned earlier, adapted in KRBH medium containing 11mM glucose for 1h, dispensed in 3 sets of microtubes, and pre-incubated with WCDD301 (0, 1, 2.5 and 5 µM) for 1h, 3h or 6h. After each pre-incubation time point, media were replaced by fresh KRBH media (100 μL) containing 1mM glucose plus respective levels of WCDD301, and incubated for 30 min. At the end of incubation, media were collected for analysis. Next, fresh KRBH media (100 μL) containing 11mM glucose plus respective levels of WCDD301 were added to the microtubes, incubated for 30 min, and collected for analysis. By measuring levels of glucagon, insulin (Promega, Lumit Immunoassay), and somatostatin (Phoenix Pharmaceuticals, Chemiluminescent Enzyme Immunoassay) in the collected media, values compared among groups using 1-Way ANOVA, α=0.05. Treatment of type 1 diabetes-human islets and dispersed islet cells with WCDD301 The donor of islets was a 26-year-old woman, who endured a long-lasting diabetes (14 years). At islet delivery time, the HbA1c level was 9.8% and both GAD antibody and Docket No.: 020153/WO ketoacidosis were positive. Following islet collection using CMRL medium and an overnight resting, islets were dispensed in 3 sets of microtubes (5 islets /microtube) and assigned as experimental groups of control, EphrinA5 and WCDD301 in a triplicate manner. Islets were preincubated in KRBH media containing 11 mM glucose for 3h. Then, media were replaced by 100 μL fresh KRBH containing 1mM glucose in the presence or absence of WCDD301 (3 µM), pre-clustered ephrin-A5 Fc (4µg/mL) or pre-clustered Fc (4 µg/mL), incubated for 30 min, and collected for analysis. Next, islets were incubated for 3h in 100 µL of fresh KRBH (11 mM glucose) in the presence or of WCDD301 (3 µM), pre-clustered ephrin-A5 Fc (4 µg/mL) or pre-clustered Fc (4 µg/mL), incubated for 30 min and collected for analysis. The rest of the islets (Approx.100), were dispersed and treated the same as islet treatment groups. Statistical analysis was done through non-parametric analysis. Immunofluorescence imaging of dispersed islet cells Dispersed islet cells of healthy humans (n=3) or mice (n=5) were seeded on coverslips coated by 5 µg/ml rhLaminin-521 (Gibco, Cat# A29249) and incubated (24 h) in RPMI 1640 supplemented by 10% FCS, 10mM HEPES and 1% penicillin-streptomycin at cell culture incubator. Then, coverslips were treated with WCDD301, preclustered ephrin-A5 Fc, or preclustered Fc in the following sequential order: KRBH (11mM glucose, 30 min), KRBH (1mM glucose, 60 min), KRBH (1mM glucose, 30 min) and KRBH (11 mM glucose, 60 min). At the end of incubation, coverslips were washed once in PBS, fixed in 2% paraformaldehyde (30 min), and washed in PBS. After 1h incubation in blocking buffer (2% BSA in PBS containing 0.1% Tween 20), coverslips were incubated with primary antibodies against glucagon (R&D Systems, Cat# MAB1249, 1:100) and EphA4 (Abclonal, Cat# A8346, 1:100; targeting the extracellular domain of EphA4, aa20-100 ) at 4°C overnight in a wet chamber. Then, following washing in PBS, coverslips were incubated in a mixture of Phalloidin 555 (Cell Signaling Technology, Cat# 8953S) and secondary antibodies (goat anti-rabbit AlexaFluor 488, Cat# A-21094, 1:1000, Molecular Probes; and goat anti-mouse AlexaFluor 633, Cat# A21052, 1:1000, Life Technologies) for 1h at room temperature. Both primary and secondary antibodies were diluted in blocking buffer containing 0.05% Tween 20. Then, coverslips were washed using PBS and counterstained by using DAPI (1:1000) for 10 min. Following 2x wash using PBS, coverslips were mounted on glass slides using ProLong antifade mountant (Invitrogen, Docket No.: 020153/WO Cat #P36980). Images were captured using the Zeiss LSM880 microscope with a Plan- Apochromat 63× 1.4 NA objective lens by setting dual-band dichroic/filter at 488 nm/561 nm laser excitation. In each slide, 25-30 fields of view were scanned and in each field of view, 3-5 cells were imaged. For image analysis, the region of interest (ROI) was manually drawn around each glucagon⁺ cell, and the intensity of F-actin or EphA4 was determined through the intensity algorithm of ImageJ software. Values of intensity were compared among groups using 1-Way ANOVA, α=0.05. Plasma stability assay of WCDD301 The pooled frozen plasma of CD-1 mice (n=20) or humans (n=6, equal males and females) was thawed in a 37°C water bath, and residual clots were removed by centrifugation (2000 rpm for 5 min). Then, plasma (98 μL) was aliquoted in each well of 96-well reaction plates using an Apricot automation workstation. Next, WCDD301 (100 μM) or Propantheline bromide (100 µM), as a positive control, was added (2 µL/well) to sets of wells assigned to blank or time points (T0, T10, T30, T60, and T120 min), and incubated in a water bath (37°C). At the end of each time point, the reaction was stopped by adding stop solution (500 μL; a mixture of 200 ng/mL of tolbutamide and labetalol in acetonitrile), mixed thoroughly, sealed, shaken (20 min) and centrifuged (1750g, 4°C, 20 min). Then, 150 μL of supernatant from each well of the reaction plate was transferred to its corresponding bioanalysis plate for LC-MS/MS analysis. The remaining level (%) of the WCDD301 after each time point was calculated using the following equation: Remaining (%) = (PAR at each time point / PAR at T0 ) x 100 (PAR stands for the peak area ratio of the WCDD301 versus internal standard). Microsomal stability assay of WCDD301 Liver microsomes (human, Corning, Cat# 452117; CD-1 mice, Xenotech, Cat# M1000) were diluted to 0.56 mg/mL in 100 mM phosphate buffer as a working solution. Then, 445 µL of the working solution was transferred into pre-warmed incubation plates T60 and NCF60. Following pre-incubation (10 min at 37°C with constant shaking), 54 µL was transferred to the blank plate, followed by adding 6 µL of NAPDH cofactor and 180 µL quenching solution. In parallel, 5 µL of WCDD301 (100 μM) was added into incubation plates (T60 and NCF60) containing microsomes and mixed 3 x thoroughly. For the NCF60 plate, 50 uL of buffer was added and mixed 3 x thoroughly; then, incubated at 37°C for 60 Docket No.: 020153/WO min with shaking. In Quenching plate T0, quenching solution(180 μL) and NAPDH cofactor (6 μL) were added. For the T60 plate, 54 µL of the mixture was placed into the Quenching plate (for 0-time point), followed by adding 44 µL NAPDH cofactor and incubation at 37°C for 60 min with shaking. Then, at 5, 15, 30, 45, and 60 min, quenching solution (180 µL) was added to the Quenching plates, and a 60 µL sample was transferred from the T60 plate per time point to the Quenching plates. For NCF60: 60 µL sample from the NCF60 incubation plate was transferred to the Quenching plate (containing quenching solution) at the 60 min time point. By shaking plates for 10 min and centrifugation (1750g, 20 min at 4°C), 80 µL of the supernatant was transferred into 240 µL HPLC water for LC- MS/MS analysis. The following first-order kinetic equation was used to calculate half-life (T_1/2), intrinsic clearance [CL_int(mic)], and hepatic clearance [CL_int(liver)]. Animal pre- Mice were purchased from the Jackson laboratory and kept at 12h light/12h dark cycle in the animal care facility at Washington University (St. Louis, MO, USA). Mice had access to water and a regular chow diet ad libitum. All mice were treated in accordance with the guidelines set out by the institutional animal care and use committee (IACUC) at Washington University based on the approved Animal Use Protocol # 20-0381. i) NOD/shiLTJ diabetic mice (Polygenic model for type 1 diabetes): Ten cohorts of independent NOD/shiLTJ mice (each 10, equal numbers of females and males) were purchased at 7-10 weeks old. Blood glucose levels were monitored twice a week using a glucometer (Glucocard ®Vital™) to find those mice at risk of diabetes. Among the at-risk mice, diabetes was confirmed when blood glucose levels stood > 200 mg/dL for 3 consecutive days. ii) STZ-induced diabetic mice: Six cohorts of C57BL/6 mice (each 10, equal numbers of females and males) fasted for 5h and were intraperitoneally injected with 40 mg/kg Streptozotocin (STZ) solution (Sigma, Cat# 572201). The STZ solution was prepared within 5 min before injection using freshly prepared citrate buffer (0.1M, Docket No.: 020153/WO pH 4.5). Nine days after the last injection, blood glucose levels were measured and those with consistent values of between 250-300 mg/dL in 2 consecutive days were considered diabetic. Oral administration of WCDD301 in diabetic mice i) Preparing oral pearl: Sustained release pearls were prepared for oral administration in the mouse models. To this end, FDA-approved excipients of Estman BioSustane™ SAIB NF (Product code: 41271-00), Agar (Biotech, Cat# C110) and L(-)Malic acid (Sigma, Cat# 202-601-5) were combined at the ratio of 1:1:0.2 (w/w/w) to prepare a homogenous paste mixture (SAIB-Agar-Malic), daily. Then, by pinching off the mixture and manually rolling, pearls were prepared at the weight range of 60-80 mg. Another type of sustained-release pearl was also prepared by using Estman BioSustane™ SAIB NF and Agar (SAIB-Agar) at the ratio of 1:1.5 (w/w). ii) Oral administration of WCDD301 in diabetic mice: 10 mg WCDD301 was pre- weighed into microtubes and reconstituted using deionized water. Then, by using a 10 µL pipette tip, the calculated dose of WCDD301 (at the volume range of 1-1.5 µL) was placed within the center of the pearls. Preparing the WCDD301 solution and placing it into pearls were performed 30-45 min before administration. For oral administration of pearls, a lab-made applicator was designed by using a disposable soft plastic transfer pipette and plunger of an insulin syringe lubricated with olive oil. iii) Dose, dosage, and excipient: The following therapeutic regimens were applied in a fed state for oral dosing of pearls containing WCDD301 (MW=247.11 g/mol). An experienced veterinarian did daily oral administration and all animal procedures during the study. - Therapeutic regimen for NOD mice with non-fasting blood glucose levels of 200-250 mg/dL(n=6-9; female/male): - Dose: 7.5 mg/kg; Dosage: Once a day; Excipient: SAIB-Agar,60 mg - Therapeutic regimen for NOD mice with non-fasting blood glucose levels of 250-350 mg/dL(n=5, female/male)and STZ mice with non- fasting blood glucose levels of 250-300 mg/dL(n=3, placebo group; n=4 treatment group, female) Docket No.: 020153/WO - Day 1: Dose: 15 mg/kg; Dosage: Once a day; Excipient: SAIB-Agar-Malic 80 mg (single attack dose) - Thereafter: Dose: 7.5 mg/kg; Dosage: Once a day; Excipient: SAIB-Agar- Malic 60 mg; by reaching blood glucose levels to 140-150 mg/dL, Excipient switched to SAIB-Agar 60 mg - Therapeutic regimen for non-diabetic NOD mice with non-fasting blood glucose levels of <140 mg/dL(female, non-diabetic mice, n=5): - Dose: 7.5 mg/kg; Dosage: Once a day; Excipient: SAIB-Agar,60 mg Measuring glucagon and insulin in plasma and pancreas Terminal blood was collected into microtubes containing K2-EDTA through cardiac puncture and plasma was separated by centrifugation at 2000g for 10 min at 4°C. Levels of glucagon and insulin were measured using the Crystal Chem Immunoassay kits. In terms of pancreas, following excision and snap freezing, 0.1g of its tail part was lysed through in order passing into 18 G, 21G, 25G, and 30G needles (each, 20 times) using lysis buffer (50mM Tris-HCl pH 7.4; 150mM NaCl; 1% Triton X100; 45 mM phenylmethylsulfonyl fluoride, and 0.77 µM Aprotinin). The suspension was centrifuged at 16000g (15 min at 4°C), and the collected supernatant was kept at -80°C while waiting for analysis. Glucose tolerance test (GTT) Following 5h of fasting, NOD mice were injected with 20% sterile glucose solution (i.p; 2 mg/kg body weight; at the volume of 10 times the body weight). Blood glucose levels were measured before injection (T0 min) by snipping the tail. Following injection, blood glucose levels were measured at time points of 15, 30, 45, 60, 90, 120, and 180 min by using the glucometer. When blood glucose levels reached above 600 mg/dL, glucometer showed HI and a random number of 650 was assigned for this condition. GTT was done at three different time points (8h, 14h, and 24h) after WCDD301 dosing, and curves were plotted using GraphPad Prism software. Results WCDD301 is a small molecule that strongly binds to the EphA4 receptor in a competitive way Docket No.: 020153/WO WCDD301 has a condensed formula of C10H17NO6 (MW = 247.11 g/mol), and its structural formula is centered on a symmetrical carbon (FIG.1A). Its synthesis follows a simple chemical procedure, which yields a white solid powder with 100% purity. Factors related to its purity and structure were as follows: Mass Spectrometry, MS: m/z 248.0; NMR: (M+H)+ 1H NMR (400 MHz): MeOD δ 4.32 (s, 6H), 2.14 (s, 9H). In terms of its interaction with the EphA4 receptor, the binding analysis showed that WCDD301 has a high binding affinity (Approx. Ki ≤ 0.13 µM) for the EphA4 receptor (FIG. 1B and C). Regarding the type of interaction, the binding of WCDD301 and the EphA4 receptor follows a competitive way of interaction. Area under curve (AUC) analysis demonstrated that in the context of a fixed level of EphA4, by increasing EphrinA5 levels, it dose- dependently removes inhibition of WCDD301 (FIG.1D). In addition, competition between WCDD301 and EphrinA5 was further shown in terms of binding to EphA4 receptor through Michaelis-Menten kinetics, in a way that by increasing WCDD301 concentration, it dose- dependently increased KD values (FIG. 1E). At this stage, by showing that WCDD301 has a high affinity for EphA4 receptor, it was questioned whether it makes an effect on glucagon secretion in α-cells. WCDD301 suppresses glucagon secretion in murine α-cells through binding to EphA4 receptor In murine dispersed islet cells, WCDD301 dose-dependently suppresses glucagon secretion in high glucose conditions (FIG.1F) without any side effect on insulin secretion (FIG. 1G). In this context, when the EphA4 receptor is inhibited using a competitive inhibitor (Rhyncophylline), it abolished the suppressive effect of both Ephrin-A5 Fc and 1.5µM WCDD301 on glucagon secretion. Interestingly, increasing the concentration of WCDD301 (3µM) removed the suppressive effect of the inhibitor on glucagon secretion (FIG.1H). In this context, there was no remarkable effect on insulin secretion (FIG.5A). Meanwhile, there was no interaction between WCDD301 and Ephrin-A5 Fc/Anti-Ephrin- A5 antibody (FIG.5B). WCDD301 suppresses glucagon secretion in α-cells of both healthy and type 1 diabetic subjects Dispersed islet cells of healthy humans as a model that mimics type 1 diabetes showed a time-dependent improvement in suppression of glucagon secretion following Docket No.: 020153/WO 1h (FIG.2A), 3h (FIG.2B), and 6h (FIG.2C) exposure to WCDD301 in both low (1mM) and high (11mM) glucose conditions. In this respect, WCDD301 showed a transient effect on insulin secretion (FIG. 2D-F), with no effect on somatostatin secretion (FIG. 6A-C). Importantly, WCDD301 remarkably reduced glucagon secretion in both islets (FIG.2G) and dispersed islet cells (FIG.2H) of a patient with type 1 diabetes. In this context, there was no side effect on insulin secretion in both islets (FIG. 2I) and dispersed islet cells (FIG.2J). WCDD301 enhances intracellular intensity of EphA4 and F-actin Immunostaining of human dispersed islet cells against F-actin (FIG. 2K) demonstrated an increase in intracellular F-actin intensity in WCDD301 treated cells (FIG. 2L), which was comparable with Ephrin-A5. In this respect, co-immunostaining of these human dispersed islet cells with EphA4 antibody (FIG.2M) showed increased intracellular EphA4 intensity in treated cells with WCDD301 (FIG.2N). In parallel, immunostaining of mouse dispersed islet cells against F-actin (FIG. 2O) showed increased intracellular F- actin intensity in treated cells with WCDD301 (FIG. 2P), which was comparable with Ephrin-A5 Fc. As well, co-immunostaining of these dispersed islet cells with EphA4 antibody (FIG. 2Q) showed increased intracellular EphA4 intensity (FIG. 2R) in treated cells with WCDD301. At this stage, by showing that WCDD301 binds to EphA4, increases F-actin intensity, and suppresses glucagon secretion, the next question was whether WCDD301 has enough metabolic stability to be considered for pre-clinical administration. WCDD301 shows strong metabolic stability WCDD301 shows strong plasma stability compared to the positive control compound, Propantheline, in both mouse (FIG. 3A and B) and human (FIG. 3C and D) plasma. Importantly, its stability in human plasma is remarkably higher (>2.7 times) than the mouse plasma. In terms of metabolic microsomal stability, WCDD301 demonstrates strong microsomal stability (FIG.3E) compared to the positive controls of Diclofenac (FIG.3F), Propafenone (FIG. 3G), and Testosterone (FIG. 3H) in mouse liver microsome preparation. Strong stability of WCDD301 was shown in human liver microsome Docket No.: 020153/WO preparation (FIG. 3I) compared to the positive controls of Diclofenac (FIG. 3J), Propafenone (FIG. 3K), and Testosterone (FIG. 3L). Interestingly, the microsomal metabolic stability of WCDD301 in human microsome preparation was stronger (>1.5 times) than the mouse one. WCDD301 normalizes blood glucose levels in mouse models Then, pre-clinical administration of WCDD301 was performed. When the blood glucose level of the NOD mice was in the range of 200-250 mg/dL, oral dosing of the formulated WCDD301 in SAIB-Agar significantly reduced blood glucose levels within a week of administration. Importantly, maintaining the treatment normalized the blood glucose level on week 2, which was sustained at the normal level during an 11-week follow-up (FIG. 4A). To further confirm that these anti-hyperglycemic effects are due to WCDD301, an experiment was designed in a way that when its administration was discontinued for a short time (48h) it resulted in hyperglycemia, and then by resuming its dosing, it reverted the blood glucose to the normoglycemic level (FIG.7A). Importantly, the efficacy of WCDD301 in case of enhanced hyperglycemia in NOD mice (300-350 mg/dL) was shown by formulating WCDD301 in SAIB-Agar-Malic excipient (FIG.4B). This treatment strategy normalized the blood glucose within a week and kept it at a normal level during a 3-week follow up. Importantly, the reduction of blood glucose levels was accompanied by suppression of hyperglucagonemia (FIG.4C) in the context of a diminished blood insulin level (FIG.4D). As well, the profile of pancreatic glucagon showed a reduction (FIG.7B), which was accompanied by a level increase in its insulin content (FIG. 7C). In these NOD mice, AUC of glucose tolerance curve showed a significant decrease in WCDD301 treated mice compared to the placebo-treated diabetic control (p<0.001). Interestingly, the elevated blood glucose level returns to its baseline at a time point, which is dependent on the time gap between the last dosing of WCDD301 and performing GTT (FIG.4G). As a further confirmatory step, it was shown that WCDD301 normalizes hyperglycemia (250-300 mg/d) in STZ-induced diabetic mice over a 4-week dosing regimen (FIG. 4E). Furthermore, in a group of non-diabetic NOD mice (n=5) when we started administration of WCDD301 at age 10 weeks and continued its administration until age 19 weeks, none of those mice showed hyperglycemia (FIG.7D). Docket No.: 020153/WO Discussion The current study is in line with long-lasting studies on the EphA4 receptor as a target for suppression of glucagon secretion in α-cells and treatment of hyperglucagonemia-hyperglycemia in diabetes. Here a novel chemical compound was developed as an agonist for the EphA4 receptor in α-cells. To this end, the designing approach was based on the characteristics of sequences in the ligand binding domain (LBD) of the EphA4 receptor (mouse EphA4: Uniport# Q03137, human EphA4: Uniport# P54764; complete homology in NCBI-Blast:100% coverage, E-value: 7e-137) in combination with those structural characteristics that have been described for EphA4 agonists. Accordingly, a series of chemical compounds were synthesized that led to WCDD301, which can be simply synthesized on a small scale for teaching laboratory courses in colleges or research laboratories. Additionally, it can be easily scaled up for pharmaceutical purposes at a low cost with absolute purity, characteristics that pave the road for further steps toward clinical trials. In terms of its structural formula, WCDD301 is a novel synthetic compound that would be submitted to the public chemistry database, PubChem. In the context of agonistic targeting of the EphA4 receptor as a therapeutic approach for the treatment of diseases, WCDD301 shows a strong affinity (with an inhibition constant of ≤0.13 µM) for EphA4 receptor, which is comparable with the strongest reported ones. In recent years, by developing high affinity binding EphA4 agonists, a variety of therapeutic applications have been proposed for those agonists. For instance, Pellecchia’s team focused on one of those developed compounds called 123C4 (with an inhibition constant of 0.64 µM) to agonistically targeting the EphA4 receptor in neuronal cells as a potential drug for the treatment of a neuronal degenerative disease, Amyotrophic lateral sclerosis (ALS). In a study by Wang’s team, they proposed that Doxazosin, an α-1 Adrenergic Antagonist, is an agonist for both EphA2 and EphA4 (with a dissociation constant of 47.6 µM) and could be a potential drug for the treatment of prostate cancer. These current findings highlight agonistically targeting of the EphA4 receptor for the treatment of hyperglycemia in T1D. Importantly, by showing the interaction between WCDD301 and EphA4 receptor at an in vitro level, this interaction was recapitulated in the α-cell by showing suppression of glucagon secretion in both isolated islets and dispersed islet cells in response to Docket No.: 020153/WO WCDD301. These manifestations reaffirm recent findings on agonistically targeting the EphA4 receptor for suppression of glucagon secretion through the RhoA signaling pathway, which was accompanied by its downstream effect on the increased intensity of F-actin in α-cells. In terms of competitive binding of WCDD301 to the EphA4 receptor, it is generally believed that the risk of unpredicted toxicity for competitive drugs is lower than the covalent drugs. A fact that has been reflected in this study by the following observations: i) in dispersed islet cells: WCDD301 did not show any side effect on the secretory function of β-cells in a range of concentrations, ii) at a pre-clinical level in diabetic NOD mice: administration of an attack dose did not cause any clinical side effect, and iii) at a pre- clinical level in non-diabetic NOD mice: it prevented the incidence of diabetes in NOD mice in a long-term administration without any clinical side effect. Thus, just as a notation, these observations could provide a notion of the side beneficiary effect of WCDD301 in terms of protecting β-cells, also. It is notable to mention that the recently FDA-approved anti-CD3antibody, Teplizumab, protects β-cells in high-risk people for T1D, which results in the prevention of progression towards higher stages of T1D. In terms of WCDD301’s effect on the downstream signaling pathway of the EphA4 receptor, it has been shown that it suppresses glucagon secretion in α-cells, which is accompanied by an increase in the intracellular intensity of both EphA4 and F-actin. Generally, to keep receptors responsive to ligands, interactions between receptors and ligands are typically terminated. To this end, in a variety of cell models, the Ephrin/Eph complex would be internalized into cells, which turns its interaction down. It seems that endocytosis of the Ephrin-EphA4 complex plays an important role in the turnover of the EphA4 on the plasma membrane for keeping the signaling pathway active. In this study, this was reflected by the presence of the N-terminal sequence of the EphA4 receptor within the α-cell following treatment with WCDD301. This phenomenon was further confirmed by showing a reduced shedding of EphA4 in the cell culture medium following treatment with WCDD301. In addition, WCDD301 increased the intracellular intensity of both EphA4 and F-actin, a phenomenon that suggests the internalization of EphA4 would trigger F-actin polymerization to suppress glucagon secretion. Since it has been shown that RhoA plays an important role in Ephrin/EphA4 signaling of α-cells, finding relationships between EphA4 internalization and RhoA signaling and other proposed Docket No.: 020153/WO signaling pathways remains elusive. WCDD301 showed very good metabolic stability in liver microsomes and plasma in both human and mouse species, which strongly motivated pre-clinical animal studies. To find the effective route of our drug administration, different routes were tested using a variety of excipients. By considering the bioavailability of competitive drugs versus covalent drugs, WCDD301 was formulated in a sustained release form using SAIB-Agar excipient. This was the first designed formula and had enough efficacy to normalize blood glucose levels (and keep the normalized level during an eleven-week follow-up) in diabetic NOD mice with initial blood glucose levels of 200-250 mg/dL. It is agreed that consistent non-fasting blood glucose around 250 mg/dL indicates initiation (early stage) of diabetes in NOD mice; thus, here it is proposed that the anti-hyperglycemic effect of WCDD301 occurred by suppression of glucagon in the presence of a level of insulin. This interpretation is in accord with the bi-hormonal theory of diabetes which proposes that hyperglycemia of diabetes is governed by both glucagon and insulin. In other words, the ratio of glucagon and insulin is an important factor for blood glucose homeostasis, a theory that has been strongly advocated, so far. In this study, it is extrapolated that in an early stage of diabetes, NOD mice restored their glycemic homeostasis by reducing glucagon levels in the presence of a level of insulin. This interpretation is supported by a recent publication on the treatment of T1D using a small chemical molecule (SRI-37330), which was accompanied by a reduction in serum glucagon and an increase in insulin. When T1D progresses towards higher stages, non-fasting blood glucose spikes above 250 mg/dL. In this study, this phase transition of T1D in NOD mice was reflected by both higher blood glucose levels (>250 mg/dL) and a phenotype of glucose tolerance test responses in relation to the time gap after WCDD301 dosing. For the treatment of mice in this scenario, another formula was designed to overcome this phase transition- induced hyperglycemia. We formulated WCDD301 in SAIB-Aar-Malic excipient that normalized the blood glucose and kept it at a normal level during a 4-week follow-up. This normalization of the blood glucose level in case of an undetectable level of insulin could be interpreted by the glucagonocentric hypothesis of diabetes, which proposes that hyperglycemia of diabetes is governed by glucagon, in a way that suppression of glucagon’s effect can normalize the blood glucose level. Though this theory is in line with the findings, another notion for interpretation of the anti-hyperglycemic effect of Docket No.: 020153/WO WCDD301 in higher stages of T1D. In this study, the plasma level of insulin was undetectable by using the ELISA kit (with a sensitivity of around 0.1 ng/mL); thus, it is uncertain whether the mice were suffering from an absolute insulin deficiency. It seems that in this case also, results could be interpreted in the context of the bi-hormonal theory of diabetes and the determinant role of glucagon: insulin ratio, a criterion that could be even a new marker for early diagnosis/progression of diabetes in conjunction with an α- cell cytoskeletal marker. In conclusion, a novel drug that binds to the EphA4 receptor on α-cells and suppresses glucagon secretion is described. Then, by formulating this highly water- soluble drug in the context of a hydrophobic excipient, a new delivery approach was also introduced to normalize blood glucose levels in T1D diabetic mouse models. The strong efficacy of WCDD301 in the normalization of blood glucose levels, accompanied by its special formulation and oral route of administration, may provide WCDD301 a special rank among proposed antidiabetic drugs/approaches for the treatment of T1D. EXAMPLE 2 – WCDD301 DEVELOPMENT AND USE IN TREATMENT OF DIABETES In this example, WCDD301 (FIG.1A) is developed and described. The compound normalizes blood glucose levels in type 1 diabetes. It has been purified (>99%) as a pro- drug. It is a highly soluble drug, with a basic isoelectric point (IP; PHi) of > 8.1. In physiological fluids, it is in both protonated (R-NH3+) and unprotonated (R-NH2) form. Based on Le Chatelier’s Principle, the highest absorption occurs in the ileal region along the alimentary tract (FIG.9). WCDD301 is highly stable. Its exosomal half-life is 93.6 to greater than 140 minutes, and its plasma half-life is 105 to greater than 289 minutes (FIG.10). WCDD301 targets the EphA4/F-actin axis (FIG.11) in alpha-cells, which intensifies the F-actin network, suppresses glucagon secretion, and makes its effect through the EphA4 receptor in alpha-cells of type 1 diabetes (T1D). WCDD301 intensifies cortical F- actin in both murine (FIG.12) and human (FIG.13) dispersed alpha-cells, and suppresses glucagon secretion in both murine and human dispersed alpha-cells (FIG.14). Blocking EphA4 in alpha-cells abolishes the suppressive effect of WCDD301 on glucagon secretion (FIG. 15). Inhibition of γ-esterase abolishes the suppressive effect of WCDD301 on Docket No.: 020153/WO glucagon secretion in dispersed murine cells (FIG.18). WCDD301 increases intracellular intensity of EphA4 in murine (FIG.19) and human (FIG. 20) dispersed alpha-cells. The suppressive effect of WCDD301 on glucagon secretion is independent of both insulin and somatostatin in both murine (FIG.21) and human (FIG.22) dispersed alpha-cells. The effect of WCDD301 on blood glucose levels in STZ-induced diabetic mice (FIG.23) and NOD mice (FIG.24). Various routes of in vivo administration were tested for efficacy. Oral administration of WCDD301 was performed in both STX-induced diabetic mice (FIG. 25A) and NOD mice (FIG. 25B) to investigate its effect on blood glucose. EXAMPLE 3 – DEVELOPMENT AND INITIAL EFFICACY EXPERIMENTS WITH WCDD302 AND WCDD0150 In this example, WCDD302 (FIG. 26A) is developed and described for use in treating type 1 diabetes by normalizing blood glucose levels. It has been synthesized and purified (>99%). It is a highly water-soluble drug and has a basic isoelectric point (IP; PHi) of > 8.1. In physiological fluids, WCDD302 will be in protonated (R-NH3+) and unprotonated (R-NH2). WCDD302 decreases glucagon secretion in mouse dispersed islet cells (FIG. 26B), as well as decreases blood glucose (FIG.26C), plasma glucagon (FIG.26D), and increases plasma insulin (FIG. 26E) in db/db mice in vivo. The effect of WCDD302 on alpha- and beta-cells of pancreatic intact islets was tested (FIG. 27), which decreases glucagon and increases insulin. WCDD302 improves imbalanced levels of EphA4 in islets in human type 2 diabetes (FIG.28). It has been found that analogs of WCDD302 can be synthesized (FIG.29). Additionally, WCDD0150 (FIG.43A) has been developed and described for use in treating type 1 diabetes by normalizing blood glucose levels. WCDD0150 has been shown to have a strong affinity for the EphA4 receptor (FIG.80A) and has low toxicity on cells (FIG. 80B). Additionally, plasma pharmacokinetics of WCDD0150 demonstrate plasma stability over time (FIG. 81A) making it a safe and effective candidate for therapeutic applications. WCDD0150 decreases glucagon secretion in mouse dispersed islet cells (FIG. Docket No.: 020153/WO 80C), as well as normalizes blood glucose levels in diabetic mouse models (FIG. 80D, FIG.80E), and decreases plasma glucagon levels (FIG.80F). WCDD0150 has no effect on plasma insulin levels (FIG.80G, FIG.80H), and normalizes the blood glucose level in an insulin-independent manner. In vivo mouse studies demonstrated similar blood glucose levels of diabetic mice treated with WCDD0150 and non-diabetic placebo-treated mice compared to the increased blood glucose levels of diabetic placebo-treated mice (FIG.80I, FIG.80J). Diabetic mice treated with WCDD0150 show improved body weight, food intake, and urine glucose levels (FIG.81B, FIG.81C, FIG.81D, FIG.81E, FIG.81F, FIG.81G). EXAMPLE 4 – Β-CELL ABLATED DISPERSED ISLET CELLS This Example describes a β-cell ablated dispersed islet cell model. The method to form the model can be found in FIG. 30. Glucagon secretion was linear in response to glucose (FIG. 31A), and insulin (FIG.31B) and somatostatin (FIG. 31C) secretion were interrogated. The model begins to secrete insulin (FIG.32) and form a single-cell pseudo- islet (FIG. 33) that is responsive to glucose (FIG. 34). This was confirmed in an αRFP model (FIG. 35). These data show that a human transdifferentiated α-cell can form an assembly of single-cell pseudo-islets by proliferation (FIG. 36). The underlying mechanism of transdifferentiation of the α-cell to a single cell pseudo-islet is based on the Hexosamine Biosynthetic Pathway, where o-glycosylated transcriptional factors play roles (FIG.37). General evolutionary genes of the process include PDX1 and Ngn3. The first line of retrograde genes includes Arx, Fox-A2, and Pax4. The second line of retrograde genes includes MafB, Nk homeobox (Nkx6.1, Nkx6.2), and Pax6. EXAMPLE 5 – WCDD301 NORMALIZES BLOOD GLUCOSE LEVELS IN DIABETIC MOUSE MODELS Abstract: Suppression of glucagon hypersecretion can normalize hyperglycemia during type 1 diabetes (T1D). Activating erythropoietin-producing human hepatocellular receptor type-A4 (EphA4) on α cells reduced glucagon hypersecretion from dispersed α cells and T1D islets from both human donor and mouse models. We synthesized a high-affinity small molecule agonist for the Docket No.: 020153/WO EphA4 receptor, WCDD301, which showed robust plasma and liver microsome metabolic stability in both mouse and human preparations. In islets and dispersed islet cells from nondiabetic and T1D human donors, WCDD301 reduced glucagon secretion comparable to the natural EphA4 ligand, Ephrin-A5. In diabetic NOD and streptozotocin-treated mice, once-daily oral administration of WCDD301 formulated with a time-release excipient reduced plasma glucagon and normalized blood glucose for more than 3 months. These results suggest that targeting the α cell EphA4 receptor by sustained release of WCDD301 is a promising pharmacologic pathway for normalizing hyperglycemia in patients with T1D (FIG.82). Methods: Immunofluorescence imaging of cells and pancreatic slices Dispersed islet cells of healthy humans (n = 3) or mice (n = 5) were seeded on coverslips coated with 5 μg/mL rhLaminin-521 (Gibco, catalog A29249) and incubated (24 hours) in RPMI 1640 supplemented by 11 mM glucose, 10% FCS, 10 mM HEPES, and 1% penicillin-streptomycin in cell culture incubator. Coverslips were treated with WCDD301, preclustered Ephrin-A5 Fc, or preclustered Fc in the following sequential order: KRBH (11 mM glucose, 30 minutes), KRBH (1 mM glucose, 60 minutes), KRBH (1 mM glucose, 30 minutes), and KRBH (11 mM glucose, 60 minutes). After treatment, coverslips were washed once in PBS, fixed in 2% paraformaldehyde in PBS (30 minutes), and again washed in PBS. After 1-hour incubation in blocking buffer (2% BSA in PBS containing 0.1% Tween 20), coverslips were incubated with primary antibodies against glucagon (R&D Systems, catalog MAB1249, 1:100) and EphA4 (ABclonal, catalog A8346, 1:100; targeting the extracellular domain of EphA4, aa 20–100) at 4°C in a wet chamber, overnight. Following a wash in PBS, coverslips were incubated in a mixture of Alexa Fluor 555 Phalloidin (Cell Signaling Technology, catalog 8953) and secondary antibodies (goat anti-rabbit Alexa Fluor 488, catalog A-21094, 1:1,000, Molecular Probes; and goat anti- mouse Alexa Fluor 633, catalog A21052, 1:1,000, Life Technologies) for 1 hour at RT. Both primary and secondary antibodies were diluted in blocking buffer containing 0.05% Tween 20. Coverslips were washed using PBS and counterstained by using DAPI (1:1,000) for 10 minutes. Following 2 washes in PBS, coverslips were mounted on glass slides using ProLong Glass Antifade Mountant (Invitrogen, catalog P36980). Images were Docket No.: 020153/WO captured using the Zeiss LSM880 microscope with a Plan-Apochromat 63× 1.4 NA objective lens by setting dual-band dichroic/filter for 405, 488, 561, and 633 nm laser excitation. For each slide, 25–30 fields of view were scanned, and in each field of view, 3–5 cells were imaged. For analysis, a region of interest (ROI) was manually drawn around each glucagon+ cell, and the intensity of F-actin or EphA4 within the ROI was determined using the intensity algorithm of ImageJ software (NIH). Values of intensity were compared among groups using 1-way ANOVA, α = 0.05. Pancreata of NOD mice (females, n = 3 per group) from non-diabetic, diabetic placebo-treated, and diabetic WCDD301-treated cohorts were excised; fixed in 10% buffered formalin for 5 days; and treated with ethanol 70% for 2 days before paraffin embedding. The paraffin-embedded tissue blocks were longitudinally sectioned in 5 μm slices and fixed on microscope slides. Following deparaffinization (through incubation in graded xylene, graded ethanol, and PBS), permeabilization (using 0.1% Triton X-100 in PBS), and background blocking (using 5% BSA solution containing 0.1% Tween 20), samples were incubated with primary antibodies (mouse anti-glucagon, Abcam, catalog ab10988; above-mentioned rabbit anti-EphA4), secondary antibodies (goat anti-mouse IgG Alexa Fluor 488; Invitrogen, catalog A-11001; goat anti-rabbit IgG Alexa Fluor 633, Invitrogen, catalog A-21070), SPY555-Actin (Cytoskeleton, catalog SC202), and DAPI. Image acquisition and analysis were performed using methods similar to those described above for dispersed islet cells. To determine the number of α cells per islet, the intensity of glucagon signal/μm² of the islet was determined as a reflective measure of α cell numbers per islet. ROIs were manually drawn around each islet, the background signal was removed by thresholding, and the intensity of the glucagon signal was determined and normalized by the islet surface area. To determine the sizes of α cells per islet, ROIs were manually drawn around α cells in each islet. Paraffin-embedding, sectioning of the embedded blocks, and Hematoxylin-Eosin staining were performed by the Anatomic and Molecular Pathology Core Labs, Washington University in St. Louis. Pharmacokinetics CD-1 mice were injected with WCDD301 subcutaneously (1 mg/kg, n = 3) or intravenously (1 mg/kg, n = 3), and blood was collected from saphenous vein directly into K2-EDTA–containing microcentrifuge tubes at 5, 10, and 15 minutes postdosing. An aliquot of 20 μL plasma was deproteinized using 200 μL of internal standard solution (100 Docket No.: 020153/WO ng/mL of labetalol and tolbutamide in acetonitrile), incubated for 10 minutes at RT, and centrifuged at 1,800g for 10 minutes at 4°C. Following 1:1 dilution of the supernatant with deionized water, 1 μL of the diluted sample was used for LC-MS/MS analysis (TripleQuad 6500, column: ACQUITY UPLC BEH C182.1 × 50 mm, 1.7 μm; flow rate: 0.6 mL/min, retention time: 1.60/1.78 WCDD301/labetalol). Results: To target the EphA4 pathway for the treatment of hyperglycemia in T1D, whereas the available compounds used for other diseases were not effective in reducing glucagon hypersecretion from either mouse or human islets (FIG.87A, FIG.87B, FIG. 87C, FIG. 87D, FIG. 87E). Disclosed is a direct interaction between WCDD301 and the EphA4 receptor in vitro (FIG.1B, FIG.1C, FIG.1D, FIG.1E) and that this interaction recapitulates the action of soluble Ephrin-A5 in both isolated islets and dispersed islet cells. The data further shows suppression by WCDD301 of glucagon secretion from isolated islets and dispersed islet cells of patients with T1D (FIG.2G, FIG.2H, FIG.2I, FIG.2J). WCDD301 also blocks arginine-stimulated glucagon secretion (FIG.88) but does not affect glucose release from mouse hepatocytes (FIG. 85G). These actions appear to signal through EphA4 by the same RhoA signaling pathway as the receptor’s natural ephrin ligand, and both are accompanied by increased cortical F-actin. Hematoxylin-Eosin staining of islets from diabetic NOD mice (FIG.83A) showed a high level of mononuclear cell infiltration in and around islets and edema in exocrine pancreas compared with nondiabetic mice (FIG. 83C). However, there was no mononuclear infiltration or apparent edema in the WCDD301-treated mice (FIG. 83E). Immunofluorescence images showed dimmed F-actin and EphA4 signals in diabetic NOD mouse islets (FIG. 83B) compared with either nondiabetic (FIG. 83D) or WCDD301- treated mice (FIG.83F). Quantification revealed significant suppression (P < 0.001) in F- actin (FIG. 83G) and EphA4 (FIG. 83H) signals within α cells of diabetic mice (47.14 ± 4.70 AU; 12.64 ± 1.12 AU) compared with nondiabetic mice (79.14 ± 4.63 AU; 18.62 ± 1.09 AU). Normal levels of F-actin and EphA4 were recovered in WCDD301-treated mice (74.50 ± 4.80 AU; 21.84 ± 1.14 AU). WCDD301 is stable in mouse and human plasma and liver microsomes, and slow- release administration increases its plasma duration in mice. WCDD301 showed strong plasma stability compared with the control compound, propantheline, in both human (FIG. Docket No.: 020153/WO 84A) and mouse (FIG.84B) plasma. As shown in Table 1, WCDD301 stability in human plasma was > 2.7-fold higher than in mouse plasma. WCDD301 also demonstrated excellent microsomal stability (FIG. 84C) compared with the controls of diclofenac, propafenone, and testosterone in an in vitro human liver microsome preparation. We observed similar stability in mouse liver microsomes (FIG. 85D) compared with the 3 control compounds. The microsomal stability of WCDD301 (Table 1) was > 1.5-fold higher in the human microsome preparation versus the mouse model. Pharmacokinetics in CD- 1 mice revealed increased plasma concentrations of WCDD301 at 15 minutes following subcutaneous injection (FIG.91A) compared with intravenous administration (FIG.91B). This difference suggests that clearing of WCDD301 allows the rate of its release into the plasma to determine its pharmacokinetics. Plasma half-life Microsomal half- Intrinsic microsomal Hepatic Drug and (min) life (min) clearance clearance controls (µL/min/mg) (mL/min/kg) mouse human mouse human mouse human mouse human WCDD301 105.1 289.1 93.6 >145 14.8 <9.6 58.7 <8.6 Propantheline 34.3 9.8 - - - - - - Diclofenac - - 47.5 4.4 29.2 313.9 115.5 282.5 Propafenone - - 2.7 5.3 516.8 262.5 2046.6 236.3 Testosterone - - 5.4 14.5 257.2 95.6 1018.5 86 Table 1: Descriptive values of plasma and microsomal stability of WCDD301 WCDD301 normalizes blood glucose in mouse models. When blood glucose levels of the diabetic NOD mice reached moderate hyperglycemia (200–250 mg/dL), once-daily oral dosing of the formulated WCDD301 in SAIB-Agar significantly reduced blood glucose levels within a week of administration. Continuing this daily treatment normalized blood glucose level during an 11-week follow-up compared with increasing hyperglycemia in the placebo-treated cohort (FIG. 85A). To verify that these glycemic effects were due to WCDD301, we discontinued its administration for 48 hours, which resulted in hyperglycemia. Euglycemia returned after resuming the WCDD301 dosing (FIG.92A). WCDD301-associated reduction of blood glucose (FIG.85A) was accompanied by suppression of glucagon levels (FIG. 85B) even in the presence of diminished blood insulin levels (FIG. 85C). Glucose tolerance was improved in NOD mice treated with WCDD301 compared with the placebo-treated diabetic control (FIG. 85D), and insulin Docket No.: 020153/WO tolerance in WCDD301-treated mice was similar to the placebo-treated diabetic controls (FIG. 85E). WCDD301 also normalized hyperglycemia in streptozotocin-induced (STZ- induced) diabetic mice over a 4-week dosing regimen (FIG. 85F). WCDD301 lowered plasma glucagon levels but did not alter glucagon-stimulated glucose output from primary mouse hepatocytes (FIG. 85G), nor did it affect euglycemia in nondiabetic NOD mice (FIG. 92B). Further, administration of WCDD301 did not alter plasma levels of other glucose homeostatic regulators, as plasma levels of glucagon-like peptide 1 (GLP-1) (FIG. 86A), glutamine (FIG. 86B), and somatostatin (FIG. 86C) were similar between WCDD301-treated diabetic NOD mice and nondiabetic placebo-treated control mice. Daily monitoring of urine glucose (FIG. 86D), food intake, (FIG. 86E), and body weight (FIG. 86F) in diabetic WCDD301-treated mice also showed phenotypes similar to nondiabetic placebo-treated mice. Histology did not indicate any alterations in numbers or sizes of α cells in WCDD301-treated mice compared to either placebo-treated diabetic or nondiabetic mice (FIG.93A and FIG.93B). WCDD301-treated animals appeared healthy and active, and blood chemistry markers for kidney function (blood urea nitrogen [BUN], creatinine), liver function (albumin [ALB], alanine aminotransferase [ALT]), and general pathology (aspartate aminotransferase [AST]) remained in the normal range (Table 2). Taken together, these data point to reduced glucagon secretion as the primary action of WCDD301, with minimal or no toxicity over a 3-month administration regimen. Parameter Results Reference interval Blood urea nitrogen (BUN) (mg/dL) 21±2.3 10-79 Creatinine (CREAT) (mg/dL) 0.2±0.1 0.2-0.5 Albumin (ALB) (g/dL) 3±0.1 1.72-3.54 Alanine aminotransferase (ALT) (IU/L) 20.5±9.5 5-394 Aspartate aminotransferase (_{AST) (IU/L) 99.5±57.5} 18-586 Table 2: Blood chemistry parameters in non-diabetic NOD mice treated with WCDD301. Discussion: Docket No.: 020153/WO Disclosed is a small molecule agonist of the EphA4 receptor to target suppression of glucagon secretion in α cells as a treatment of hyperglucagonemia-hyperglycemia in diabetes. Our chemical design utilized knowledge of the ligand binding domain (LBD) of the EphA4 receptor (mouse EphA4: Uniprot Q03137, human EphA4: Uniprot P54764) combined with structural characteristics of known EphA4 agonists. A series of compounds were synthesized that led to WCDD301, through a 3-step synthesis from commercial starting materials it is readily scaled up for investigational new drug–enabling studies and clinical supply. WCDD301 shows a strong affinity (Ki ≤ 0.13 μM) for the EphA4 receptor, comparable with other reported EphA4 agonists. In recent years, EphA4 agonists have been proposed for a variety of therapeutic applications, including amyotrophic lateral sclerosis and prostate cancer. To target this pathway for the treatment of hyperglycemia in T1D, whereas the available compounds used for other diseases were not effective in reducing glucagon hypersecretion from either mouse or human islets (FIG. 87A, FIG. 87B, FIG.87C, FIG. 87D, FIG. 87E), we showed a direct interaction between WCDD301 and the EphA4 receptor in vitro (FIG.1B, FIG.1C, FIG.1D, FIG.1E) and that this interaction recapitulates the action of soluble Ephrin-A5 in both isolated islets and dispersed islet cells. The data further show suppression by WCDD301 of glucagon secretion from isolated islets and dispersed islet cells of patients with T1D (FIG.2G, FIG.2H, FIG.2I, FIG.2J). WCDD301 also blocks arginine-stimulated glucagon secretion (FIG.88) but does not affect glucose release from mouse hepatocytes (FIG. 85G). These actions appear to signal through EphA4 by the same RhoA signaling pathway as the receptor’s natural ephrin ligand, and both are accompanied by increased cortical F-actin. Noncovalent drugs, including WCDD301 as a reversible competitive agonist (FIG. 1D, FIG. 1E, FIG. 1H), generally show lower risks of unpredicted toxicity than covalent drugs. The data are consistent with low toxicity both in vitro and in vivo. WCDD301 does not affect the secretory function of β cells over a range of concentrations (FIG.2D, FIG. 2E, FIG.2F), and WCDD301 administration achieves euglycemia without clinical signs of illness, hepatotoxicity, or nephrotoxicity (Table 2). Blood chemistry assays after WCDD301 administration show normal levels of BUN, creatinine, ALB, and transaminases (AST, ALT) that are established markers for nephrotoxicity, hepatotoxicity, or multiple-organ injury. Interestingly, prophylactic administration of WCDD301 appears Docket No.: 020153/WO to prevent the development of diabetes in NOD mice (FIG.91B), which is consistent with histology showing the prevention of mononuclear cell infiltration in islets of diabetic NOD mice (FIG.83E). This may suggest a role for WCDD301 similar to teplizumab in protecting β cells in people at risk for T1D. WCDD301 agonizes the EphA4 receptor and suppresses glucagon hypersecretion from α cells (FIG. 1F, FIG. 2A, FIG. 2B, FIG. 2C) accompanied by increased F-actin polymerization (FIG.2K, FIG.2L, FIG.2O, FIG.2P, FIG.83B, FIG.83D, FIG.83F, FIG. 83G, FIG.83H). The activated ephrin-EphA4 complex is expected to be internalized into cells to terminate signaling. This mechanism is consistent with the data showing increased immunostaining of the N-terminal sequence of the EphA4 receptor within the α cell following treatment with WCDD301 (FIG. 2M, FIG. 2N, FIG. 2Q, FIG. 2R). This phenomenon is further consistent with our data showing reduced shedding of EphA4 into the cell culture medium following treatment with WCDD301 (FIG.90D). WCDD301 shows excellent stability in liver microsomes and plasma in both the human and mouse. Given the high clearance rates of hydrophilic compounds, which is in line with intravenous pharmacokinetic findings (FIG.91B), we formulated WCDD301 in a time-release form using SAIB-Agar excipient. This formulation normalized blood glucose within 2 weeks and maintained normalized levels during an 11-week follow-up (FIG.84A) in diabetic NOD mice with moderate hyperglycemia, consistent with early-stage diabetes in NOD mice. Increased plasma duration of WCDD301 following subcutaneous administration (FIG.91B) suggests that the oral sustained-release pearl provides a long plasma bioavailability. The proposed mechanism of EphA4 agonism by WCDD301 suppressing glucagon hypersecretion and normalizing hyperglycemia was tested with numerous control experiments. We did not observe any effects of WCDD301 on plasma levels of glucose homeostatic regulators (GLP-1, somatostatin, glutamine) (FIG.86A, FIG.86B, FIG.86C), α cell number/size (FIG 93A, FIG. 93B), glucosuria (FIG. 86D), food intake (FIG. 86E), body weight (FIG. 86F), or peripheral insulin sensitivity (FIG. 85E). We also tested WCDD301 in various ex vivo models including intact isolated islets and dispersed islet cells from both humans and mice (FIG.2G, FIG.2H, FIG.2I, FIG.2J, FIG.1F, FIG.1G). Dispersed islet cells approximate the T1D situation where α cells are separated from β cells, although this preparation does not recapitulate possible interactions from residual Docket No.: 020153/WO or malfunctioning β cells. This limitation is partially addressed by our validation that WCDD301 shows similar action on islets from human T1D donors (FIG.2G, FIG.2H). In conclusion, disclosed is the development of a small molecule drug, WCDD301, that agonizes the EphA4 receptor on α cells and suppresses glucagon hypersecretion. By formulating this water-soluble molecule with a hydrophobic excipient, we showed that oral delivery of this compound normalizes blood glucose in T1D mouse models. Taken together, these data suggest that the α cell EphA4 receptor is a druggable target for normalization of hyperglycemia in patients with T1D.

Claims

Docket No.: 020153/WO CLAIMS What is claimed is: 1. An EphA family agonist comprising a structure as given by Structure (I): (I), wherein: R₁ comprises COOC₃H₇, or COOC₄H₉; R2 comprises OH, COOCH3, COOC2H5, COOC3H7, or COOC4H9; R₃ comprises NH₂, NH⁺, or NH₂COCH₃; and R4 comprises OH, COOCH3, COOC2H5, COOC3H7, or COOC4H9.   2. The EphA family agonist of claim 1, comprising the structure as given by Structure (II):  (II), wherein: or R6 comprises CH3, C2H5, or C3H7; and R₇ comprises H₂, CH₃, or C₂H₅. 3. The EphA family agonist of claim 2, comprising the structure as given by Structure (III): Docket No.: 020153/WO   , R₉ comprises H₂, CH₃, or C₂H₅; and, R10 comprises H2, CH3, or C2H5. 4. The EphA family agonist of claim 3, comprises the structure selected from: or 5. The EphA family agonist of claim 4, comprising an EphA4 agonist. Docket No.: 020153/WO 6. The EphA family agonist of claim 5, wherein the EphA family agonist lowers glucagon levels in a diabetic patient. 7. The EphA family agonist of claim 6, wherein the EphA family agonist normalizes blood sugar in the diabetic patient. 8. A composition for the treatment of a diabetic patient in need, the composition comprising a therapeutically effective amount of an EphA family agonist, wherein the EphA family agonist comprises a structure as given by Structure (I): (I), wherein: R1 comprises COOC3H7, or COOC4H9; R₂ comprises OH, COOCH₃, COOC₂H₅, COOC₃H₇, or COOC₄H₉; R3 comprises NH2, NH⁺, or NH2COCH3; and R4 comprises OH, COOCH₃, COOC₂H₅, COOC₃H₇, or COOC₄H₉. 9. The composition of claim 8, wherein the EphA family agonist comprises a structure as given by Structure (II):  (II), wherein: R5 comprises CH3, C2H5, C3H7, or C4H9; R₆ comprises CH₃, C₂H₅, or C₃H₇; and Docket No.: 020153/WO R7 comprises H2, CH3, or C2H5. 10. The composition of claim 9, wherein the EphA family agonist comprises a structure as given by Structure (III):   , R9 comprises H2, CH3, or C2H5; and, R₁₀ comprises H₂, CH₃, or C₂H_5. 11. The composition of claim 10, wherein the EphA family agonist comprises the structure selected from: or

Docket No.: 020153/WO . 12. The composition of claim 11, wherein the EphA family agonist comprises an EphA4 agonist. 13. The composition of claim 12, wherein the EphA family agonist lowers glucagon levels in a diabetic patient. 14. The composition of claim 13, wherein the EphA family agonist normalizes blood sugar in the diabetic patient. 15. The composition of claim 14, further comprising Eastman BioSustane SAIB NF, Agar, and L(-)Malic acid formulated in a pearl for oral administration. 16. The composition of claim 14, wherein the EphA4 agonist blocks EphA4 receptors in alpha-cells. 17. A method of treating a diabetic patient in need, the method comprising administering a therapeutically effective amount of an EphA family agonist, the EphA family agonist comprising a structure as given by:

Docket No.: 020153/WO (I), wherein: R 1 COOC3H7, or COOC4H9; R₂ comprises OH, COOCH₃, COOC₂H₅, COOC₃H₇, or COOC₄H₉; R3 comprises NH2, NH⁺, or NH2COCH3; and R₄ comprises OH, COOCH₃, COOC₂H₅, COOC₃H₇, or COOC₄H₉. 18. The method of claim 17, wherein the EphA family agonist comprises the structure given by Structure II:    (II), wherein: or R₆ comprises CH₃, C₂H₅, or C₃H₇; and R7 comprises H2, CH3, or C2H5. 19. The method of claim 18, wherein the EphA family agonist comprises the structure given by Structure III:    Docket No.: 020153/WO (III), R8 comprises CH3, C2H5, C3H7, or C4H9; R₉ comprises H₂, CH₃, or C₂H₅; and, R10 comprises H2, CH3, or C2H5. 20. The method of claim 19, wherein the EphA family agonist comprises a structure selected from: or