CN116675779A - A short peptide targeting Src kinase and its application in systemic fungal infection - Google Patents

Abstract

The invention belongs to the technical fields of biomedicine and molecular biology, and specifically relates to a short peptide targeting Src and its application in systemic fungal infection. The present invention finds through research that the above-mentioned polypeptide promotes the host's anti-fungal immune response by inhibiting the STING-Src interaction. The polypeptide is derived from amino acid residues 1-18 of the STING protein, and the N-terminus of the polypeptide is fused with a TAT cell-penetrating peptide. After the polypeptide enters the cell, it competitively binds to Src, inhibits the formation of Src and STING complexes, thereby reducing the inhibitory effect of STING on the CLR pathway; significantly increases the mRNA transcription levels of inflammatory cytokines TNF-α, IL-6, etc. The ability to remove pathogenic fungi, so it has good practical application value.

Description

A short peptide targeting Src kinase and its application in systemic fungal infection

technical field

The invention belongs to the technical fields of biomedicine and molecular biology, and specifically relates to a short peptide targeting Src and its application in systemic fungal infection.

Background technique

The information disclosed in the Background of the Invention is only intended to increase the understanding of the general background of the invention, and is not necessarily to be taken as an acknowledgment or any form of suggestion that the information constitutes the prior art that is already known to those skilled in the art.

Candida species are the most common causes of fungal infections in humans, causing approximately 400,000 systemic invasive infections each year with a mortality rate of approximately 40%. Among them, Candida albicans is the most common pathogenic species. Systemic infection with Candida remains associated with high mortality due to issues of drug toxicity (polyenes) and drug resistance (azoles and echinomycins). Therefore, it is urgent to develop new antifungal treatments.

STING (Stimulator of interferon genes) is an adapter protein on the endoplasmic reticulum, which can specifically recognize natural cyclic dinucleotide ligands synthesized by cyclic GMP-AMP synthetase (cGAS), thereby Activate STING. Ligand-bound STING is transported to the Golgi apparatus and initiates a cascade of downstream signals, including the recruitment and activation of serine/threonine protein kinase (TBK1) and interferon-regulated transcription factor (IRF3) and nuclear factor (NF- κB), and then produce type I interferon and pro-inflammatory cytokines, including interleukin 6 (IL-6), tumor necrosis factor (TNF-α) and so on. However, there are still few studies on the antifungal signaling pathway of STING, and further research is needed.

Contents of the invention

In view of the deficiencies in the prior art, the purpose of the present invention is to provide a short peptide targeting Src and its application in systemic fungal infection. Specifically, it promotes host antifungal immune response by inhibiting STING-Src interaction. The polypeptide is derived from amino acid residues 1-18 of the STING protein, and the N-terminal of the polypeptide is fused with a TAT cell-penetrating peptide. After the polypeptide enters the cell, it competitively binds to Src, inhibits the formation of Src and STING complex, thereby reducing the inhibitory effect of STING on the CLR pathway; significantly increases the mRNA transcription levels of inflammatory cytokines TNF-α, IL-6, etc. The ability to eliminate pathogenic fungi. Based on the above research results, the present invention has been accomplished.

In order to realize the above-mentioned technical purpose, the technical scheme provided by the present invention is as follows:

The first aspect of the present invention provides a short peptide targeting Src kinase, which at least includes

The 1-18 amino acid residues (including human hN18 and mouse mN18) residues at the N-terminal of STING protein are fused with a cell-penetrating peptide to enhance cell penetration. Experiments have proved that the N18 polypeptide cell-penetrating peptide specifically binds to Src kinase through the PXXP domain.

Specifically, cell penetrating peptides are a type of short peptides that can carry macromolecular substances into cells, including naturally occurring cell penetrating peptides and artificially synthesized cell penetrating peptides. In a specific embodiment of the present invention, the used The cell-penetrating peptide derived from human immunodeficiency virus (HIV)-1 amino acid residues 47-57 (YGRKKRRQRRR), which has been widely used to deliver exogenous macromolecules into cells.

Further, in order to track the location of the polypeptide after it enters the cell, the N-terminus of the polypeptide is labeled with biotin. Therefore, the polypeptide sequence of the present invention is any of the following:

1. hN18:Biotin-YGRKKRRQRRR-MPHSSLHPSIPCPRGHGA (SEQ ID NO.1);

2. mN18: Biotin-YGRKKRRQRRR-MPYSNLHPAIPRPRGHRS (SEQ ID NO. 2).

Specifically, the N18 polypeptide provided by this application has been proved to inhibit STING-Src binding at the cellular level, promote the recruitment and activation of downstream Syk kinases, thereby enhancing the activation of the C-type lectin receptor pathway; significantly enhance the The mRNA transcription levels of factors such as TNF-α and IL-6 can enhance the host's anti-fungal immune response and help to eliminate pathogenic bacteria.

The second aspect of the present invention provides a method for preparing the above-mentioned short peptide. The preparation method includes chemical synthesis. Specifically, the above-mentioned polypeptide can be synthesized by a solid-phase polypeptide synthesis method.

The third aspect of the present invention provides the application of the above short peptide in the preparation of products for systemic fungal infections.

The function of the product is at least one of the following (a1)-(a4):

(a1) specifically binding to Src, thereby inhibiting the binding of Src to STING;

(a2) promote the formation of Src-Syk complex;

(a3) promoting the expression of antifungal inflammatory cytokines and chemokines;

(a4) Promotes clearance of pathogenic fungi in invasive fungal infections.

The fourth aspect of the present invention provides a medicament for treating systemic fungal infection, which at least contains the above-mentioned short peptide.

The fifth aspect of the present invention provides a method for treating systemic fungal infection, the method comprising administering the above-mentioned short peptide or the above-mentioned drug to a subject.

The subject in the present invention refers to an animal that has been the object of treatment, observation or experiment, preferably a mammal, most preferably a human.

Beneficial technical effects of the above-mentioned one or more technical solutions:

(1) The N18 polypeptide in the above technical scheme specifically binds to Src kinase, inhibits the combination of Src and STING, thereby alleviating the inhibitory effect of STING on the CLR signaling pathway; enhances inflammatory cytokines (TNF-α, IL-6) Expression (mRNA transcription level and protein secretion level); at the cellular level and animal level, the immune response of the host against fungal infection is enhanced.

(2) Compared with the full-length protein, the N18 polypeptide in the above technical solution has a small molecular weight, is easy to process and synthesize, has weak immunogenicity, and relatively weak side effects; and it has better absorption with cell-penetrating peptides, and it is easy to digest with polypeptide labels. Follow up and observe to provide reference for clinical treatment of fungal diseases.

Description of drawings

The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention.

Figure 1: After the Sting ^KO mice were systemically infected with a low dose of Candida albicans (1×10 ⁵ /mouse), their survival rate was significantly increased within 21 days, and their body weight decreased more slowly than that of the wild type.

Figure 2: After the Sting ^KO mice were systemically infected with a high dose of Candida albicans (2×10 ⁵ /mouse), their survival rate was significantly increased within 21 days, and their body weight decreased more slowly than that of the wild type.

Figure 3: After Sting ^KO and wild-type mice were systemically infected with Candida albicans (1×10 ⁵ /mouse), the fungal loads in kidney, liver and spleen were significantly lower than those of wild-type mice.

Figure 4: Histopathological staining of the kidneys of Sting ^KO and wild-type mice after systemic infection with Candida albicans (1×10 ⁵ /mouse). H&E staining showed that the kidney damage of Sting ^KO mice was significantly lower than that of wild type; PAS staining showed that compared with wild type, only a small amount of hyphae were visible in the kidneys of Sting ^KO mice; Ly6G staining showed less infiltration of neutrophils.

Figure 5: Bone marrow-derived dendritic cells (BMDCs) of Sting ^KO and wild-type mice were cultured in vitro, and treated with dextran Zymosan, heat-killed Candida albicans yeast state (Yeast) and hyphae state (Hyphae), etc. Stimulate. In addition, exogenous DNA (interferon stimulating DNA, ISD) that activates the STING signaling pathway was added as a positive control. qPCR detection found that Sting ^KO 's BMDCs were stimulated by fungi, and their ability to secrete inflammatory cytokines was enhanced.

Figure 6: Bone marrow-derived dendritic cells (BMDC) of Sting ^KO and wild-type mice were cultured in vitro, and treated with dextran Zymosan, heat-killed Candida albicans yeast state (HKCA-Y) and hyphae state (HKCA-H ) and so on were stimulated respectively, and ELISA test found that the ability of Sting ^KO BMDC to secrete inflammatory cytokines was enhanced after being stimulated by fungi.

Figure 7: Bone marrow-derived dendritic cells (BMDCs) of Sting ^KO and wild-type mice were cultured in vitro, and stimulated with dextran Zymd for 15, 30, and 60 minutes, respectively. Western blot detection showed that BMDCs of Sting ^KO were stimulated by fungi, Enhanced activation of CLR signaling pathway.

Figure 8: Immunofluorescence diagram of the distribution of Biotin-mN18 polypeptide in BMDC cells;

Figure 9: BMDC was pretreated with mN18 polypeptide (5 μM, 10 μM) and mN18 mutant polypeptide (10 μM) for 2 hours, then added dextran particles Zymosan, heat-killed Candida albicans yeast state (Yeast) and hyphae state (Hyphae) Stimulate for two hours. The transcriptional levels of inflammatory cytokines TNF-α, IL-6 and chemokine CXCL1 were detected by qPCR, and it was found that the ability to secrete the above factors was enhanced after the BMDCs treated with the polypeptide were stimulated by fungi.

Figure 10: BMDC were pretreated with mN18 polypeptide (10 μM) and mN18 mutant polypeptide (10 μM) for 2 hours, and then stimulated with dextran particles Zymd for 15 and 30 minutes. Syk-Src complex formation was detected by immunoprecipitation technique. It was found that complex formation was enhanced in peptide-treated BMDCs stimulated by fungi.

Figure 11: The systemic infection model of Candida albicans was established in C57BL/6 mice. The mN18 group was intraperitoneally injected with mN18 polypeptide (5 mg/kg) every day for the first three days, the mice in the mutant group were injected with mN18 mutant polypeptide (5 mg/kg) every day for the first three days, and the mice in the control group were injected with PBS solution every day for the first three days. The mouse body weight change graph and survival curve graph obtained by measuring the mouse body weight every day, a total of 21 days.

Figure 12: The systemic infection model of Candida albicans was established in C57BL/6 mice. The mN18 group was intraperitoneally injected with mN18 polypeptide (5 mg/kg) every day for the first three days, the mice in the mutant group were injected with mN18 mutant polypeptide (5 mg/kg) every day for the first three days, and the mice in the control group were injected with PBS solution every day for the first three days. On the fifth day, the kidneys, livers and spleens were taken and ground, and the fungal load in the organs was detected.

Figure 13: The systemic infection model of Candida albicans was established in C57BL/6 mice. The mN18 group was intraperitoneally injected with mN18 polypeptide (5 mg/kg) every day for the first three days, the mice in the mutant group were injected with mN18 mutant polypeptide (5 mg/kg) every day for the first three days, and the mice in the control group were injected with PBS solution every day for the first three days. On the fifth day, kidneys were taken for H&E staining, PAS staining and Ly6G staining.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It should be noted that the terminology used here is only for describing specific embodiments, and is not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural, and it should also be understood that when the terms "comprising" and/or "comprising" are used in this specification, they mean There are features, steps, operations, means, components and/or combinations thereof.

As mentioned above, there are still few studies on the STING antifungal signaling pathway, and further research is needed.

In view of this, the research of the present invention found that after the pathogenic fungus Candida albicans systemically infected model mice, STING exerted the effect of negatively regulating the immune response of the host. Its mechanism of action is mainly through the 18 amino acid residues at its N-terminus (human STING: 1-MPHSSLHPSIPCPRGHGA-18; mouse STING: 1-MPYSNLHPAIPRPRGHRS-18) forming a complex with the tyrosine kinase Src, resulting in the inability of the downstream kinase Syk Recruited and activated by Src. Syk plays a pivotal role in the key signaling pathway of anti-fungal infection - C-type lectin (CLR) signaling pathway, and the inhibition of its activity leads to the inability of the host to normally exert anti-fungal immune response. Aiming at the property of STING to block the formation of the Src-Syk complex, the researchers synthesized amino acids at positions 1-18 of the STING protein (hN18 (human source) and mN18 (mouse source)), and fused the TAT membrane-penetrating peptide at the N-terminus (YGRKKRRQRRR). Cell-penetrating peptides enhance the ability of short peptides to enter cells and improve the absorbability of short peptides. After the short peptide enters the cell, it competitively binds to Src, inhibits the formation of the Src and STING complex, thereby reducing the inhibitory effect of STING on the antifungal signaling pathway, which is of great significance in promoting the host's antifungal immune response and controlling the infection process.

Specifically, in a typical embodiment of the present invention, a short peptide targeting Src kinase is provided, which at least includes amino acid residues at positions 1-18 (including human hN18 and mouse mN18) derived from the N-terminal of the STING protein Base, and fused with cell-penetrating peptides to enhance cell penetration. Experiments have proved that the N18 polypeptide cell-penetrating peptide specifically binds to Src kinase through the PXXP domain.

Among them, the cell penetrating peptide is a type of short peptide that can carry macromolecular substances into cells, including naturally occurring cell penetrating peptides and artificially synthesized cell penetrating peptides. In a specific embodiment of the present invention, the used The cell-penetrating peptide is derived from amino acid residues 47-57 (YGRKKRRQRRR) of human immunodeficiency virus (HIV)-1, which has been widely used to deliver exogenous macromolecules into cells.

Further, in order to track the location of the polypeptide after it enters the cell, the N-terminus of the polypeptide is labeled with biotin. Therefore, the short peptide sequence of the present invention is any of the following:

1. hN18:Biotin-YGRKKRRQRRR-MPHSSLHPSIPCPRGHGA (SEQ ID NO.1);

2. mN18: Biotin-YGRKKRRQRRR-MPYSNLHPAIPRPRGHRS (SEQ ID NO. 2).

Specifically, the N18 polypeptide provided by this application has been proved to inhibit STING-Src binding at the cellular level, promote the recruitment and activation of downstream Syk kinases, thereby enhancing the activation of the C-type lectin receptor pathway; significantly enhance the The mRNA transcription levels of factors such as TNF-α and IL-6 can enhance the host's anti-fungal immune response and help to eliminate pathogenic bacteria.

It should be noted that although the present invention takes the human-derived and mouse-derived N18 polypeptides of the STING protein as examples, it is obvious that the N18 polypeptides from other sources of the STING protein also fall within the protection scope of the present invention.

In yet another specific embodiment of the present invention, a method for preparing the above-mentioned short peptide is provided. The preparation method includes chemical synthesis. Specifically, the above-mentioned polypeptide can be synthesized by a solid-phase peptide synthesis method.

In yet another specific embodiment of the present invention, the application of the above-mentioned short peptides in the preparation of products for systemic fungal infections is provided.

The function of the product is at least one of the following (a1)-(a4):

(a1) specifically binding to Src, thereby inhibiting the binding of Src to STING;

(a2) promote the formation of Src-Syk complex;

(a3) promoting the expression of antifungal inflammatory cytokines and chemokines;

(a4) Promotes clearance of pathogenic fungi in invasive fungal infections.

In the present invention, the antifungal inflammatory cytokines include but not limited to TNF-α, IL-6, and the chemokines include but not limited to CXCL-1.

The fungi include but are not limited to Candida, Aspergillus, Cryptococcus and Penicillium and other fungi (ie pathogenic fungi) that are pathogenic to animals (including humans), further Candida, such as Candida albicans.

The product can be a medicine or an experimental reagent, which can be used in basic research, such as the related research on the mechanism of fungal infection.

In yet another specific embodiment of the present invention, a drug for treating systemic fungal infection is provided, and the drug at least contains the above-mentioned short peptide.

Specifically, the medicine may also include a pharmaceutically acceptable carrier. The pharmaceutically acceptable carrier can be buffer, emulsifier, suspending agent, stabilizer, preservative, excipient, filler, coagulant and adjuster.

Blending agent, surfactant, diffusing agent or defoamer.

The medicament may also include a pharmaceutically acceptable carrier. The pharmaceutically acceptable carrier can be virus, microcapsule, liposome, nanoparticle or polymer and any combination thereof. The delivery vehicle of the pharmaceutically acceptable carrier can be liposome, biocompatible polymer (including natural polymer and synthetic polymer), lipoprotein, polysaccharide, lipopolysaccharide, artificial virus envelope, inorganic (including metal ) particles, and bacterial or viral (eg baculovirus, adenovirus and retrovirus), phage, cosmid or plasmid vectors.

In the present invention, the drug can also be used in combination with other drugs for the prevention and/or treatment of fungal infections, and other preventive and/or therapeutic compounds can be administered simultaneously with the main active ingredients, even in the same composition medicine.

The medicament may also administer other prophylactic and/or therapeutic compounds alone in a separate composition or dosage form different from the main active ingredient. Some doses of the principal ingredient may be administered concurrently with other therapeutic compounds, while other doses may be administered alone. During the course of treatment, the dosage of the drug of the present invention can be adjusted according to the severity of symptoms, the frequency of relapses and the physiological response to the treatment regimen.

The medicament of the present invention can be administered into the body by known means. For example, by intravenous systemic delivery or local injection into the tissue of interest. Administration is optionally via intravenous, transdermal, intranasal, mucosal or other delivery methods. Such administration can be via single dose or multiple doses. It will be appreciated by those skilled in the art that the actual dosage to be administered in the present invention may vary largely depending on various factors such as the target cell, the type of organism or its tissue, the general condition of the subject to be treated, the route of administration, method of administration, etc.

In yet another specific embodiment of the present invention, a method for treating systemic fungal infection is provided, the method comprising administering the above-mentioned short peptide or the above-mentioned drug to a subject.

The subject in the present invention refers to an animal that has been the object of treatment, observation or experiment, preferably a mammal, most preferably a human.

The present invention will be further described in conjunction with specific examples, and the following examples are only for explaining the present invention, and do not limit its content. If the specific experimental conditions are not indicated in the examples, usually follow the conventional conditions or the conditions recommended by the reagent company; the reagents and consumables used in the following examples can be obtained from commercial sources unless otherwise specified.

The present invention is further explained and illustrated by the following examples, but does not constitute a limitation of the present invention. It should be understood that these examples are only for illustrating the present invention and are not intended to limit the scope of the present invention. In the following examples, the test methods for indicating specific conditions are usually carried out according to conventional conditions.

Example 1: STING inhibits host antifungal immune response

By constructing a mouse model of systemic infection of Candida albicans, it was found that STING negatively regulates the host's immune response against fungal infection at both the animal level and the cellular level.

1.1 STING plays a negative role in the systemic fungal infection model

A systemic infection model was established by injecting Candida albicans through the tail vein of Sting knockout C57BL/6j mice (Sting ^KO ). Compared with wild-type mice, the survival rate of Sting ^KO mice after infection with low/high doses of C. albicans was significantly improved within 21 days (Fig. 1, 2); fungal load in kidney, liver and spleen were significantly lower than wild-type mice (Figure 3). H&E staining of infected kidneys showed that the kidney damage of Sting ^KO mice was significantly lower than that of wild type; PAS staining showed that compared with wild type kidneys, Sting ^KO mice had only a small amount of hyphae visible; Ly6G staining showed neutrophils There was less infiltration (Figure 4). The above results suggest that STING participates in and negatively regulates the host's immune response against fungal infection.

1.2 STING inhibits the activation of C-type lectin receptor (CLR) signaling pathway

By culturing bone marrow-derived macrophages (BMDM) and dendritic cells (BMDC) in vitro, and stimulating them with dextran and heat-killed Candida albicans, the ability of Sting ^KO immune cells to secrete inflammatory cytokines was found Enhanced (Fig. 5, 6). Western blot experiments proved that STING inhibits the phosphorylation of important kinases in the CLR pathway, including Syk and PLC-γ, and then inhibits the activation of transcription factors NF-κB and MAPK kinases (Figure 7). These results suggest that STING negatively regulates the activation of CLR signaling pathway.

Example 2: STING protein binds Src kinase through the N-terminal 18 amino acids

STING mainly relies on its N-terminal 18 amino acids to interact with Src, hindering the recruitment and activation of downstream Syk kinase by Src, and inhibiting the activation of downstream NF-κB signaling pathway. Therefore, the N-terminal 18 amino acid polypeptide of the STING protein was designed, and a polypeptide with cell permeability was synthesized, the sequence of which is as follows. The ₈ -PXXPXP- ₁₃ domain critical for Src binding was mutated to AXXAXA (underlined). After the design is completed, entrust Nanjing Yuanpeptide Co., Ltd. to synthesize and purify the peptide based on the above sequence.

1. hN18: Biotin-YGRKKRRQRRR-MPHSSLH PSIPCP RGHGA (SEQ ID NO.1);

2. hN18 mutant: Biotin-YGRKKRRQRRR-MPHSSLH ASIACA RGHGA (SEQ ID NO.3)

3. mN18: Biotin-YGRKKRRQRRR-MPYSNLH PAIPRP RGHRS (SEQ ID NO.2)

4. mN18 mutant: Biotin-YGRKKRRQRRR-MPYSNLH AAIARA RGHRS (SEQ ID NO.4)

Take mouse BMDC cells, add Biotin-mN18 polypeptide (5μM) and incubate for 2 hours, detect the fluorescence intensity of the polypeptide and the distribution in the cells by laser confocal microscope, the results show that: after adding the polypeptide for 2 hours, Biotin-mN18 enters the cells and Evenly distributed in the cell; after adding red fluorescent-labeled dextran particles (Texas red-labeled Zymosan) to stimulate for 20 minutes, the polypeptide translocates to the phagosome membrane and co-localizes with Src (Figure 8).

Example 3: Verifying the effect of polypeptides on the expression of inflammatory cytokines

Add Biotin-mN18 polypeptide (5 μM, 10 μM) to mouse BMDC for pretreatment for 2 hours, and then add dextran, heat-killed Candida albicans and other stimulations respectively. After 2 hours, the mRNA transcription levels of inflammatory cytokines TNF-α, IL-6 and chemokine CXCL-1 were detected by RT-PCR. Figure 9 shows that mN18 polypeptide pretreatment can significantly promote the secretion of pro-inflammatory cytokines and chemokines.

Embodiment 4: Verify the influence of polypeptide on the formation of Syk-Src complex

Add Biotin-mN18 polypeptide (5μM) to mouse BMDC for pretreatment for 2 hours, add dextran to stimulate for 15 and 30 minutes, and detect whether the formation of Syk-Src complex is affected by immunoprecipitation technique. Figure 10 shows that mN18 polypeptide pretreatment promotes complex formation.

Example 5: Validation of the role of polypeptides in the Candida albicans systemic infection model

5.1 Construction of mouse systemic fungal infection model

SPF grade, 7-8 weeks old C57BL/6 male mice, body weight 20-22g, purchased from Beijing Weitong Lihua Company, fed in SPF Animal Center of Shandong University, divided into 3 groups: mN18 (15 mice respectively) ), the mN18 mutation group (11 rats) and the control group (15 rats). All three groups were injected with Candida albicans through the tail vein of the mice (2×10 ⁵ fungal cells per mouse). The mN18 group was intraperitoneally injected with mN18 polypeptide (5 mg/kg) every day for the first three days, the mice in the mutant group were injected with mN18 mutant polypeptide (5 mg/kg) every day for the first three days, and the mice in the control group were injected with PBS solution every day for the first three days. After the mice were given the systemic fungal infection model, the body weight changes and survival curves of the mice in each group were recorded every day for a total of 21 days.

5.2 Histopathological observation and evaluation

A systemic infection model was established by injecting Candida albicans into the tail vein of mice (2×10 ⁵ fungal cells per mouse). The mN18 group was intraperitoneally injected with mN18 polypeptide (5 mg/kg) every day for the first three days, and the mice in the mutant group were intraperitoneally injected with mN18 mutant polypeptide (5 mg/kg) every day for the first three days. Kidney tissue was taken, fixed in 4% paraformaldehyde, and sent to Wuhan Xavier Biotechnology Co., Ltd. for hematoxylin-eosin staining (H&E) staining and glycogen staining (schiffperiodic acid shiff, PAS) and neutrophils (Ly6G) staining. A panoramic slide scanner was used to observe the pathological conditions of the kidney tissue, and to evaluate the basic pathological changes in the slices, such as congestion, congestion, hemorrhage, edema, degeneration, necrosis, hyperplasia, fibrosis, organization, granulation tissue, and inflammatory changes. Each parameter is divided into 0-4 grades according to the severity, and the higher the grade, the more serious the pathological damage of the colon tissue.

The results showed that compared with the intraperitoneal injection of the mutant polypeptide group, the mN18 polypeptide group significantly reduced the weight loss of the mice (Figure 11), and the ability of the kidneys to clear pathogenic fungi was significantly improved (Figure 12). The results of H&E staining showed that the mN18 polypeptide group H&E staining showed that the kidney injury in the mN18 polypeptide group was significantly weaker than that in the control group; PAS staining showed that only a small amount of mycelium was visible in the kidneys of the mN18 polypeptide group; Ly6G staining indicated that neutrophil infiltration in the kidneys of the mN18 polypeptide group was less (Figure 13).

Matters not covered in the present invention are known technologies.

The above-mentioned embodiments are only to illustrate the technical concept and characteristics of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and not to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention shall fall within the protection scope of the present invention.

Claims (10)

1. A Src kinase-targeted short peptide, which at least comprises amino acid residues 1-18 at the N-terminal of STING protein, and is further modified with a cell-penetrating peptide.

2. A Src kinase targeted short peptide according to claim 1 wherein the cell penetrating peptide is TAT cell penetrating peptide.

3. A Src kinase targeted short peptide according to claim 1, wherein said short peptide is further modified with biotin.

4. A Src kinase targeted short peptide according to any one of claims 1 to 3, wherein said short peptide is as shown in any one of SEQ ID No.1 to 2.

5. The method for producing a short peptide according to any one of claims 1 to 4, wherein the method comprises synthesizing by a chemical method; further, the chemical method includes a solid-phase polypeptide synthesis method.

6. Use of the short peptide according to any one of claims 1 to 4 for the preparation of a product for systemic fungal infection.

7. The use according to claim 6, wherein the function of the product is at least one of the following (a 1) - (a 4):

(a1) Specifically binds Src, thereby inhibiting Src binding to STING;

(a2) Promoting Src-Syk complex formation;

(a3) Promoting expression of antifungal inflammatory cytokines and chemokines;

(a4) Promoting the elimination of pathogenic bacteria in invasive fungus infection models.

8. The use of claim 7, wherein the antifungal inflammatory cytokine comprises TNF- α, IL-6 and the chemokine comprises CXCL-1;

the fungi include candida, aspergillus, cryptococcus and penicillium, and further candida including candida albicans.

9. The use according to any one of claims 6 to 8, wherein the product is a pharmaceutical or experimental agent for use in basic research.

10. A medicament for the treatment of systemic fungal infections, characterized in that it contains at least a short peptide according to any one of claims 1-4.