WO2008007818A1

WO2008007818A1 - Novel use of aimp1 for controlling glucose level

Info

Publication number: WO2008007818A1
Application number: PCT/KR2006/002753
Authority: WO
Inventors: Sung-Hoon Kim
Original assignee: Seoul National University Industry Foundation
Priority date: 2006-07-13
Filing date: 2006-07-13
Publication date: 2008-01-17

Abstract

The present invention relates to a novel use of AIMPl for controlling glucose level. More particularly, the present invention relates to a method for controlling glucose level in a subject, and a method for preventing or treating hypoglycemia or disease associated with hypoglycemia in a subject, which comprise administering to a subject in need thereof an effective amount of AIMPl, its functional equivalent or a nucleic acid encoding them. Also, the present invention relates to a composition for controlling glucose level in a subject, and a composition for preventing and treating hypoglycemia or disease associated with hypoglycemia in a subject, which comprises AIMPl, its functional equivalent or a nucleic acid encoding them as an effective ingredient.

Description

NOVEL USE OF AIMPl FOR CONTROLLING GLUCOSE LEVEL

Technical Field

The present invention relates to a novel use of AIMPl for controlling glucose level.

Background Art

Glucagon is a single-chain polypeptide hormone containing 29 amino acid residues and having a molecular weight of nearly 3500. Glucagon secretion, like that of insulin, is controlled by the interplay of gastrointestinal food products, hormones, and other factors. Glucagon is secreted from pancreatic α-cells in response to stimuli which include (i) falling blood glucose levels, (ii) the physiological increments in amino acids which follow a protein meal, (iii) vigorous exercise, (iv) starvation, and (v) hypoglycermia.

The role of glucagon, in general, its action is reported to be antagonistic to those of insulin. The glucagon generally has effects opposite to those of insulin, including, primarily, stimulating hepatic glycogenolysis , increasing hepatic glucose output and thereby increasing blood glucose levels. Following a carbohydrate meal, pancreatic β-cells secrete insulin and pancreatic α-cell secretion of glucagon is suppressed; this allows cells to store glucose in liver, muscle, and adipose tissue. Conversely, during starvation, stimulation of glucagon secretion and suppression of insulin secretion direct breakdown and efficient utilization of energy source stored intracellularly, initially liver glucogen, and subsequently- adipose tissue fat.

Because of glucagon is effect to increase blood glucose levels in individuals, it is widely used clinically in the acute management of severe hypoglycemia complicating insulin therapy of insulin-dependent (type 1) diabetes mellitus .

Hypoglycemia, characterized by low blood glucose levels, results in autonomic and adrenergic, as well as neroglycopenic, symptoms. Hypoglycemia may occur in any diabetic subject treated with insulin or with an oral hypoglycemic agent. Since the actions of glucagon are counter regulatory of those of insulin, it may contribute to the hyperglycemia that accompanies Diabetes mellitus (Lund P. K et al., Proc. Natl. Acad. Sci. USA, 79:345-349, 1982).

Meanwhile, AIMPl (ARS-interacting multi-functional protein 1) was previously known as the p43 protein and renamed by the present inventors (Sang Gyu Park et al . , Trends in Biochemical Sciences, 30:569-574, 2005). The AIMPl is a protein consisting of 312 amino acids, which binds to a multi-tRNA synthetase complex (Deutscher, M. P., Method Enzymol, 29, 577-583, 1974; Dang C. V. et al . , Int. J. Biochem. 14, 539-543, 1982; Mirande, M. et al . , EMBO J. 1, 733-736, 1982; Yang D. C. et al . , Curr. Top Cell. Regul . 26, 325-335, 1985) to increase the catalytic activity of the multi-tRNA synthetase complex (Park S. G. et al . , J. Biol. Chem. 274, 16673-16676, 1999) . It is known that the AIMPl is secreted from various types of cells, including prostate cancer cells, immune cells and transgenic cells, and its secretion is induced by various stimulations such as TNFα and heat shock (Park S. G. et al . , Am. J. Pathol., 166, 387- 398, 2005; Barnett G. et al . , Cancer Res. 60, 2850-2857, 2000) . The secreted AIMPl works on diverse target cells such as monocytes, macrophages, endothelial cells and fibroblast cells.

Disclosure Technical Problem

The present inventors found that the AIMPl has the activity of glucagon-like hormone for the homeostasis of glucose by releasing from the pancreatic α-cells at low concentration of glucose, inhibiting the glucose uptake and inducing glycogenolysis in liver and stimulating lipolysis in adiopocytes to increase blood level of glucose, thereby completing the present invention.

Therefore, it is an object of the present invention to provide a novel use of AIMPl for controlling glucose level .

Technical Solution To achieve the above object, in one aspect, the present invention provides a method for controlling glucose level in a subject, a method for preventing or treating hypoglycemia, or a method for preventing or treating disease associated with hypoglycemia, each of the methods comprising administering to a subject in need thereof an effective amount of one selected from the group consisting of:

(a) an isolated polypeptide having the amino acid sequence set forth in SEQ ID NO: 1;

(b) an isolated polypeptide having the amino acid sequence homology of at least 70% to the polypeptide (a) ; and

(c) an isolated nucleic acid encoding the polypeptide (a) or (b) .

In another aspect, the present invention provides a composition for controlling glucose level in a subject, a composition for preventing or treating hypoglycemia, or a composition for preventing or treating disease associated with hypoglycemia, each of the compositions comprising as an effective ingredientthe polypeptide, its functional equivalent or a nucleic acid encoding them.

In still another aspect, the present invention provides a use of the polypeptide, its functional equivalent or a nucleic acid encoding them for the preparation of an agent for treating hypoglycemia or an agent for treating disease associated with hypoglycemia.

Hereinafter, the present invention will be described in detail.

The present invention is characterized by providing novel use of the AIMPl, which has the activity of controlling glucose level .

First, in order to identify the activity of AIMPl, the present inventors prepared the protein extracts from different mice tissues and examined the localization and forms of AIMPl in tissues (see Example <1-1> and Example <1- 2>) . As a result, the high level of AIMPl was observed in salivary gland and pancreas (see Fig 1) . And the AIMPl was present in pancreas as a free form (see Fig 2) . Furthermore, the results of immunohistochemical staining and immunoGold staining of mice pancreas showed that the AIMPl was enriched in α-cell along with glucagon (see Figs 3 to 5) . Since AIMPl is co-localized with glucagon, the present inventors tested whether AIMPl secretion is controlled by the variation of blood glucose concentration (see Example <2- 1> and Example <2-2>) . As a result, it was found that AIMPl was secreted upon low glucose concentrations (see Figs 6 and 7) .

Also, the present inventors tested whether the AIMPl would induce the glucagon secretion (see Example 3) . As a result, glucagon secretion was stimulated by AIMPl (see Fig 8) .

Since AIMPl was secreted at low glucose concentration and then induces the secretion of glucagon, it may work directly or indirectly via the secretion of glucagon to restore normal glucose levels in blood. To delineate this possibility, the present inventors infused AIMPl into the mice and monitored the blood level changes of various molecules related to glucose metabolism (see Example 4) . As a result, AIMPl raised the plasma glucagon, glucose, free fatty acid and glycerol levels (see Fig 9) . The AIMPl induced increase of glucose prior to glucagon enhancement suggests that it could directly control the glucose level in addition to its stimulation of glucagon secretion. Furthermore, the present inventors examined the effect of AIMPl on glucose and free fatty acid uptake (see Example 5) , glycogenolysis (see Example 6) and lipolysis (see Example 7) . As a result, AIMPl inhibited the uptake of glucose in hepatocyte although it did not affect the uptake of fatty acid (see Fig 11) . Also AIMPl induced glycogenolysis (see Fig 12) and lipolysis (see Fig 13).

The in vitro test results confirmed that AIMPl is secreted to blood in hypoglycemic condition to stimulate glycogenolysis and also to induce lipolysis to supply glycerol and fatty acid to restore the normal glucose levels. To address whether the suggested activity of AIMPl is also observed in vivo, the present inventors examined the phenotypes related to glucose metabolism in AIMPl-deficient mice (see Example 8) .

As a result, the plasma glucose and free fatty acid levels were lower in AIMPl-deficient mice than those in wild type mice. Also, AIMPl-deficient mice had a higher glycogen content in the liver compared with the wild type mice (see Fig 14) . It showed that insulin and glucagon are present at normal levels in AIMPl-deficient mice, suggesting that AIMPl would not regulate the expression levels of glucagon and insulin (see Fig 15) . Meanwhile, upon fasing, the blood glucose concentration was rapidly decreased in AIMPl^^" mice , whereas wild type mice maintained a certain glucose level (see Fig 16) .

A rapid decrease in glucose in AIMPl^^" mice under starving conditions may result from the defects in glucose compensation, which should be mediated by AIMPl. In other words, their glucose dependency would be more severe than that of wild type mice since AIMPl^^" mice are defective in glucose compensation response. To check this possibility, the present inventors compared the glucose sensitivity between wild type mice and mutant mice. As a result, AIMPl^"''^" mice showed faster removal of glucose from the blood than wild type mice (see Fig 17) .

In summary, AIMPl is secreted from the pancreatic α- cell at low glucose levels. The secreted AIMPl cooperatively works for the homeostasis of glucose through different organs, by inducing glucagon secretion in the pancreas, inhibiting glucose uptake and triggering glycogenolysis in the liver, and stimulating lipolysis in adipocytes to increase blood level of glucose (see Fig 18) . Thus the AIMPl has glucagon-like hormonal activity. The AIMPl having the above-described activities can be used for the controlling glucose level in a subject. Accordingly, the present invention provides a method for controlling glucose level in a subject, which comprises administering an effective amount of the AIMPl or a nucleic acid encoding the AIMPl to a subject in need thereof.

As used herein, the term "controlling glucose level" refers to changing, adjusting or varying blood glucose levels to maintain normal glucose levels in a subject. Preferably, it refers to increasing the glucose level when the blood glucose level in the subject is lower than the normal glucose level .

As used herein, the term "subject" means mammals, particularly animals including human beings. Also, as used herein, the term "effective amount" refers to an amount of

AIMl effective in controlling blood glucose level in vivo or in vi tro.

The AIMPl used in the inventive methods may have an amino acid sequence set forth in SEQ ID NO: 1. The inventive AIMPl includes functional equivalents thereof. As used herein, the term "functional equivalents" refers to polypeptides which exhibit substantially identical physiological activity to the AIMPl having an amino acid sequence set forth in SEQ ID NO: 1. The term "substantially identical physiological activity" refers to the activity of controlling glucose level in a subject; preferably, increasing glucose level in a subject. The functional equivalents may be polypeptides having a sequence homology (i.e., identity) of at least 70%, preferably at least 80%, and more preferably at least 90% to the amino acid sequence set forth in SEQ ID NO: 1. For example, the term functional equivalents refers to polypeptides comprising the amino acid sequence having sequence homology of 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87 %, 88 %, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% and 100% to the amino acid sequence of SEQ ID NO: 1. The functional equivalents may include, for example peptides produced by as a result of addition, substitution or deletion of some amino acid of SEQ ID N0:l. Substitutions of the amino acids are preferably conservative substitutions. Examples of conservative substitutions of naturally occurring amino acids are as follows: aliphatic amino acids (GIy, Ala, Pro) , hydrophobic amino acids (lie, Leu, VaI), aromatic amino acids (Phe, Tyr, Trp) , acidic amino acids (Asp, GIu), basic amino acids (His, Lys, Arg, GIn, Asn) and sulfur-containing amino acids (Cys, Met) . Furthermore, the functional equivalents also include variants with deletion of some of the amino acid sequence of the inventive AIMPl. Deletion or substitutions of the amino acids are preferably located at regions that are not directly involved in the physiological activity of the inventive polypeptide. In addition, the functional equivalents also include variants with addition of several amino acids in both terminal ends of the amino acid sequence of the AIMPl or in the sequence. Moreover, the inventive functional equivalents also include polypeptide derivatives which have modification of some of the chemical structure of the inventive polypeptide while maintaining the fundamental backbone and physiological activity of the inventive polypeptide. Examples of this modification include structural modifications for changing the stability, storage, volatility or solubility of the inventive polypeptide.

Sequence identity or homology is defined herein as the percentage of amino acid residues in the candidate sequence that are identical with amino acid sequence of AIMPl (SEQ ID NO: 1) , after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity, and not considering any conservative substitutions (as described above) as part of the sequence identity. None of N-terminal, C-terminal, or internal extensions, deletions, or insertions into the amino acid sequence of AIMPl shall be construed as affecting sequence identity or homology. Thus, sequence identity can be determined by standard methods that are commonly used to compare the similarity in position of the amino acids of two polypeptides. Using a computer program such as BLAST or FASTA, two polypeptides are aligned for optimal matching of their respective amino acids (either along the full length of one or both sequences or along a predetermined portion of one or both sequences) . The programs provide a default opening penalty and a default gap penalty, and a scoring matrix such as PAM 250 (a standard scoring matrix,- see Dayhoff et al . , in Atlas of Protein Sequence and Structure, vol. 5, supp . 3 (1978)) can be used in conjunction with the computer program. For example, the percent identity can be calculated as the follow. The total number of identical matches multiplied by 100 and then divided by the sum of the length of the longer sequence within the matched span and the number of gaps introduced into the longer sequences in order to align the two sequences.

Most preferably, the functional equivalents of AIMPl may include SNPs (single nucleotide polymorphism) for the AIMPl. Four SNPs for the AIMPl are known (see NCBI SNP database) . Namely, the following SNPs are known: substitution of 79^th alanine (Ala) to proline (Pro) (SNP accession no. rs3133166) (SEQ ID NO: 2); substitution of

104^th threonine (Thr) to alanine (Ala) (SNP accession no. rsl7036670) (SEQ ID NO: 3); substitution of 117^th threonine

(Thr) to alanine (Ala) (SNP accession no. rs2230255) (SEQ ID NO: 4) ; and base substitution of codon (ctg) for 8^th leucine

(Leu) to codon (etc) , no substitution the amino acid (Leu) in the amino acid sequence of the full-length AIMPl (SEQ ID

NO: 1) .

The polypeptide according to the present invention can be prepared by a genetic engineering method using the expression of recombinant nucleic acid encoding the same. For example, the inventive polypeptide can be prepared by a genetic engineering method comprising the steps of: inserting a nucleic acid sequence or its fragment encoding the inventive peptide into a recombinant vector comprising one or more expression control sequences which are operatively linked to the nucleic acid sequence to control the expression of the nucleic acid sequence; transforming a host cell with the resulting recombinant expression vector; culturing the transformed cell in a medium and condition suitable to express the nucleic acid sequence; and isolating and purifying a substantially pure protein from the culture medium. Genetic engineering methods for preparing peptides are known in the art (Maniatis et al . , Molecula Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory (1982); Sambrook et al . , supra; Gene Expression Technology, Method in Enzymology, Genetics and Molecular Biology, Methods in Enzymology, Guthrie & Fink (eds.), Academic Press, San Diego, Calif. (1991); Hitzeman et al . , J. Biol. Chem. , 255, 12073-12080 (1980) ) .

Alternatively, the inventive peptide can be chemically synthesized according to any technique known in the art (Creighton, Proteins: Structures and Molecular Principles, W. H. Freeman and Co., NY 1983). Namely, the inventive peptide can be prepared by conventional liquid or solid phase synthesis, fragment condensation, F-MOC or T-BOC chemistry (Chemical Approaches to the Synthesis of Peptides and Proteins, Williams et al . , Eds., CRC Press, Boca Raton Florida, 1997; A Practical Approach, Atherton & Sheppard, Eds., IRL Press, Oxford, England, 1989).

The recombinant peptide prepared by the genetic engineering method or the chemically synthesized peptide can be isolated and purified according to methods known in the art, including extraction, recrystallization, various chromatographic techniques (e.g., gel filtration, ion exchange, precipitation, adsorption, reverse phase, etc.), electrophoresis and counter current distribution. The inventive polypeptide was administered alone or with a pharmaceutically acceptable carrier for controlling glucose level in a subject. As used herein, the term "pharmaceutically acceptable carrier" refers to a substance that is physiologically acceptable and does not generally cause allergic reactions, such as gastrointestinal disorder and dizziness etc. or reactions similar thereto when administered into subject.

Meanwhile, the inventive polypeptide may further comprise a pharmaceutically acceptable carrier and can be formulated in any form according to any method known in the art .

For oral administration, the inventive polypeptide can be formulated in the form of ingestible tablets, buccal tablets, troches, capsules, elixirs, suspensions, syrups, wafers, and the like. These preparations may also comprise diluents (e.g., lactose, dextrose, sucrose, mannitol, sorbitol, cellulose and/or glycine), lubricants (e.g., silica, talc, stearic acid and magnesium or calcium salt thereof, and/or polyethylene glycol) in addition to the active ingredient. Among various preparations, tablets may also comprise binders, such as magnesium aluminum silicate, starch pastes, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose and/or polyvinylpyrrolidone, and, if desired, may further comprise disintegrating agents, such as starches, agar, alginic acid or a sodium salt thereof, absorbents, colorants, flavors and/or sweeteners.

The formulations for parenteral administration preferably include injection formulations, such as isotonic aqueous solution or suspension formulations, and ointment formulations. The injection formulations may be prepared using suitable dispersing or wetting agents, and suspending agents, according to the known methods in the art. For example, each ingredient is dissolved in saline or buffer and then can be prepared into a dosage form for injection.

Also, the inventive polypeptide may be administered by various routes according to any method known in the art.

Namely, it may be administered by oral or parenteral routes.

For example, the parenteral routes are include method for administering to intramuscular, intravenous, intracutaneous, intraarterial, intramarrow, intrathecal, intraperitoneal, intranasal, intravaginal, intrarectal, sublingual and subcutaneous .

The effective amount of the inventive polypeptide may be suitably determined by considering various factors, such as age, body weight, health condition, sex, disease severity, diet and excretion of a subject in need of treatment, as well as administration time and administration route. Preferably, the effective amount of the inventive peptide is about 0.1 to 100 mg/kg body weight/day, more preferably 10 to 100 mg/kg body weight/day.

Furthermore, the inventive method includes administering to the subject in need thereof an isolated nucleic acid encoding an polypeptide having the amino acid sequence set forth in SEQ ID NO: 1 or an polypeptide having the amino acid sequence homology of at least 70% to the polypeptide. The nucleic acid includes DNA, cDNA or RNA. Preferably, the nucleic acid of the invention comprises the nucleotide sequence selected from the group consisting of SEQ ID NO. 5 to SEQ ID NO. 9. The nucleotide sequence selected from the group consisting of SEQ ID NO. 5 to SEQ ID NO. 9 encodes the above described four SNPs for the AIMPl, respectively. The nucleic acid can be isolated from a natural source or be prepared by a genetic engineering method known in the art .

The inventive nucleic acid may be administered using an expression vector, such as a plasmid or viral vector. For example, the nucleic acid can be administered by inserting it into an expression vector, and then introducing the expression vector into a target cell by any method known in the art, such as infection, transfection or transduction.

A gene transfer method using a plasmid expression vector is a method of transferring a plasmid DNA directly to mammalin cells, which is an FDA-approved method applicable to human beings (Nabel, E. G., et al., Science, 249:1285-

1288, 1990) . The plasmid DNA has an advantage of being homogeneously purified, unlike the viral vector. As the plasmid expression vector that can be used in the present invention, there can be used mammal expression plasmids known in the pertinent art. For example, they are not limited to, but typically include pRK5 (European Patent No. 307,247), pSVlβB (International Patent Publication 91/08291 A) and pVL1392 (PharMingen) . The plasmid expression vector comprising the nucleic acid according to the invention can be introduced into tumor cells by the methods known in the pertinent art, for example, transient transfection, micro injection, transduction, cell fusion, calcium phosphate precipitation, liposome-mediated transfection, DEAE Dextran- mediated transfection, polybrene-mediated transfection, electroporation, gene gun and other known methods of introducing DNA into cells (Wu et al . , J^". Bio. Chem. , 267:963-967, 1992; Wu and Wu, J. Bio. Chem., 263:14621- 14624, 1988) . Also, the virus expression vector comprising the nucleic acid according to the invention is not limited to, but includes retrovirus, adenovirus, herpes virus and avipox virus, lenti virus. The retroviral vector is constructed so that non- viral proteins can be produced by the viral vector within the infected cells by the elimination or modification of all the virus genes. The main advantages of the retroviral vector for gene therapy lie in the fact that a quantity of genes are transferred into replicative cells, the genes transferred into cell DNA are accurately integrated and continuous infection does not occur after the gene transfection (Miller, A. D., Nature, 1992, 357:455-460). The retroviral vector approved by FDA is constructed using PA317 amphotropic retrovirus package cells (Miller, A. D. and Buttimore, C, Molec. Cell Biol., 6:2895-2902, 1986).

As non-retroviral vectors, there is adenovirus as mentioned above (Rosenfeld, M.A., et al . , Cell, 68:143-155, 1992; Jaffe, H.A. et al . , Nature Genetics, 1:372-378, 1992; Lemarchand, P. et al . , Proc. Natl. Acad. Sci. USA, 89:6482- 6486, 1992). The main advantages of the adenovirus lie in the fact that it can transfer a quantity of DNA fragments (36kb genome) and it is capable of infecting non-replicative cells with a very high titer. Also, the herpes virus can be usefully used for human gene therapy (Wolfe, J.H., et al . , Nature Genetics, 1:379-384, 1992). The lentivirus is a kind of retrovirus and developed to new retroviral vector since the late 1990s. The lentiviral vector is constructed by- modifying HIV backbone. It has high transfection efficiency in dividing and non-diving cells since it is not influenced by cell cycle unlike other retroviral vectors. Thus it has been developed as potential vectors for gene transfer in the cell therapy field using hematopoietic and keratinocyte stem cells, since transfection efficiency of the lentiviral vector in slow-dividing cell such as hematopoietic cell is higher than that of other viral vectors. Besides, other known suitable viral vectors can be used.

The viral vector can be administered by the known methods. For example, it can be administered locally, pareterally, orally, intranasally, intravenously, intramuscularly, subcutaneously, or by other suitable means.

Also, the nucleic acid according to the invention may further comprise pharmaceutically acceptable carriers or excipients. Such carriers or excipients include a dispersion agent, wetting agent, suspension agent, diluent and filler. The ratio of a specific, pharmaceutically acceptable carrier and the expression vector contained in the pharmaceutical composition of the invention may be determined by the solubility and chemical properties of the composition, specific administration method, etc. The therapeutically or preventively effective amount can be suitably selected according to the subject to be administered, age, individual variation and disease conditions.

In other aspect, the inventive AIMPl can be used for preventing or treating disease related with controlling glucose level in a subject. Thus, the present invention provides a method for preventing or treating hypoglycemia, which comprises administering of an effective amount of the AIMPl, its functional equivalent or an amino acid encoding them to a subject in need thereof.

And, the present invention provides a method for preventing or treating disease associated with hypoglycemia, which comprises administering of an effective amount of the AIMPl, its functional equivalent or an amino acid encoding them to a subject in need thereof.

As used herein, the term "hypoglycemia" refers to a condition characterized by an abnormally low blood glucose level. Preferably, the hypoglycemia is a pathologic state that blood glucose level is less than 70 mg/dl . As used herein, the term "preventing" refers to reducing or inhibiting a risk of hypoglycemia in subjects not suffering from hypoglycemia. As used herein, the term "treating/treatment" refers to improving, alleviating or complete cure of symptoms or syndromes. For Example, the inventive AIMPl, its functional equivalent or an amino acid encoding them can be used for preventing or treating hypoglycemia or disease associated with hypoglycemia by supplementing or recovering an abnormally low glucagon level .

The hypoglycemia can occur in diabetes mellitus, in certain endocrine disorders such as hypopituitarism, Addison's disease, and myxedema, in disorders relating to liver malfunction, in instances of renal failure, and in pancreatic cancer(see U. S Pat. Publication No. 20050107441). Increasing blood glucose levels can alleviate the symptoms associated with these hypoglycemic disorders.

Especially, the hyperglycemia occurs frequently in individuals suffering from Type 1 diabetes mellitus patients administering insulin or Type 2 diabetes mellitus patients administering oral hypoglycemic agents.

Diabetes mellitus is a metabolic disorder which is defined by the presence of chronically elevated levels of blood glucose (hyperglycemia) . Insulin-dependent (Type 1) diabetes mellitus results from a destruction of pancreatic β-cells with consequent loss of insulin production, which results in hyperglycemia. People with Type 1 diabetes have an absolute requirement for insulin therapy in order to ensure survival. In marked contrast, non-insulin-dependent (Type 2) diabetes mellitus is often characterized by herperglycemia in the presence of higher than normal levels of plasma insulin (hyperinsulinemia) . Thus, in Type 2 diabetes, tissue which control carbohydrate metabolism are believed to have decreased sensitivity to insulin. Progression of the Type 2 diabetic state is associated with increasing concentrations of blood glucose and coupled with a relative decrease in the rate of glucose-induced insulin secretion. The primary aim of treatment in both forms of diabetes mellitus is the same, namely, the reduction of blood glucose levels to as near normal as possible. The treatment of Type 1 diabetes necessarily involves the administration of insulin. In contrast, the treatment of Type 2 diabetes frequently does not require the administration of insulin. Initial therapy of Type 2 diabetes may be used on diet and lifestyle changes augmented by therapy with oral hypoglycemic agent such as the sulfonylureas. However, treatment with insulin or oral hypoglycemic agents may lead to hypoglycemia, including coma. The hypoglycemia can result in substantial morbidity and even death.

In other aspect, the present invention provides a composition for controlling glucose level in a subject comprising the AIMPl, its functional equivalent or an amino acid encoding them as an effective ingredient .

In another aspect, the present invention provides a composition for preventing or treating disease related with controlling glucose level in a subject comprising the AIMPl, its functional equivalent or an amino acid encoding them as an effective ingredient.

In still another aspect, the present invention provides a use of the AIMPl, its functional equivalent or an amino acid encoding them for the preparation of an agent for treating disease related with controlling glucose level in a subject .

Hereinafter, the present invention will be described in detail by examples. It is to be understood, however, that these examples are for illustrative purpose only and are not construed to limit the scope of the present invention.

Brief Description of the Drawings

FIG.l is the results of Western blot analysis showing the tissue-dependent variationsof AIMPl. MRS: methionyl-tRNA synthetase QRS: glutaminyl-tRNA synthetase FIG. 2 is the results of size exclusion chromatography showing the AIMPl forms in lung and pancreas . EPRS: glutamyl-prolyl-tRNA synthetase

RRS: arginyl-tRNA synthetase

FIG. 3 is the results of immunohistochemical staining showing the localization of AIMPl in pancreatic islet. Green: AIMPl is stained with FITC-conjugated antibody

Red: nuclei are stained with propidium iodide.

FIG. 4 is the results of immunohistochemical staining showing the localization of AIMPl and glucagon in pancreatic α-cells and the localization of AIMPl and insulin in pancreatic β-cells.

FIG. 5 is the results of immunoGold staining showing the localization of AIMPl in pancreatic α-cells and β-cells.

FIG. 6 is the results of Western blot analysis showing secretion of AIMPl by pancreatic stimulation through the cardiac perfusion of the various concentration of glucose .

FIG. 7 is the results of Western blot analysis showing AIMPl secretion from pancreatic α-cells according to the glucose concentration. WCL: whole cell lysates

FIG. 8 is the results showing the effect of AIMPl from aTCl clone 9 on glucagon secretion (n=3, The values are means + standard deviation) .

FIG. 9 is a graph showing the effect of AIMPl on the blood levels of glucagon (A) , insulin (B) , glucose (C) , lactate (D) , free fatty acid (E) and glycerol (F) (n=5, The values are means ± standard deviation) .

FIG. 10 is a graph showing the effect of AIMPl on glucose and free fatty acid uptake in adopocytes and muscle cells (n=3, The values are means + standard deviation) .

FIG. 11 is a graph showing the effect of AIMPl on glucose and free fatty acid uptake in hepatic cells (n=3, The values are means ± standard deviation) .

FIG. 12 is a graph showing the effect of AIMPl on glycogenlysis (n=3 , The values are means ± standard deviation) .

FIG. 13 is a graph showing the effect of AIMPl on lipolysis (n=3 , The values are means + standard deviation).

FIG. 14 is a graph showing levels of blood glucose (A) , free fatty acid (B) and liver glycogen (C) in AIMPl- deficient mice (AIMPl^"7") and wild type mice (AIMP1^+/+) .

FIG. 15 is the results of immunohistochemical staining of pancreatic islet in AIMPl-deficient mice (AIMPl^" ^/") and wild type mice (AIMP1^+/+) . FIG. 16 is the results showing blood glucose level of AIMPl-deficient mice (AIMPl^"7") and wild type mice (AIMP1^+/+) upon fasting.

FIG. 17 is the results of intraperitoneal glucose tolerance test of AIMPl-deficient mice (AIMPl^"7") and wild type mice (AIMP1^+/+) (n=9, The values are means ± standard deviation) .

FIG. 18 is a schematic diagram showing hormonal activity of AIMPl for the homeostasis of glucose. An arrow indicates promotion, and a T-shaped bar indicates repression.

Best Mode for Carrying Out the Invention

Example 1: Examination for localization of AIMPl in tissues

<1-1> Examination for the tissue-dependent variation of AIMPl level Tissue-dependent variations of the protein levels were determined for AIMPl, and two tRNA synthetases, MRS (methionyl-tRNA synthetase) and QRS (glutaminyl-tRMA synthetase) that are the components of the multi-tRNA synthetase complex. The protein extracts were prepared from different mouse tissues and the protein levels were determined by Western blot analysis with their specific antibody.

Various isolated mouse organs (bone marrow, spleen, kidney, heart, adrenal gland, pituitary gland, salivary gland, thymus, duodenum, bladder, small intestine, small brain, thyroid, lung, large brain, large intestine, liver, pancreas) were placed in RIPA buffer containing 20 mM Tris-

HCl, pH 7.6, 150 mM NaCl, 10% glycerol, 1% Triton X-100,

0.1% SDS, 0.5% Sodium deoxycholate, 1 mM EDTA, 1 mM PMSF, 5 g/ml aprotinin, 5 g/ml chymostatin, 5 g/tnl leupeptin, 1 mM NaF, 1 mM Sodium orthovanadate and 12 mM - glycerophosphate, minced using sharp-point scissors and lysed with Dounce homogenizer. The lysates were centrifuged at 15,000 rpm for 20 min at 4°C. The protein concentrations in the supernatants were quantified by Bradford assay and subjected to Western blotting with the antibodies specific to human AIMPl, glutaminyl-tRNA synthetase (QRS) and methionyl-tRNA synthetase (MRS) .

As a result, while methionyl- (MRS) and glutaminyl- tRNA synthetases (QRS) showed the relatively similar levels, AIMPl level showed significant tissue-dependent variation. Among the examined tissues, the extremely high level of AIMPl was observed in salivary gland and pancreas (see Fig D •

<l-2> Examination for AIMPl forms in lung and pancreas

Considering that AIMPl exists as one of the components for the macromolecular tRNA synthetase complex, the high enrichment of AIMPl in salivary glands and the pancreas suggests that some portion of AIMPl may exist as free form that is not bound to the complex. To test this possibility, we extracted proteins from lung containing low concentrations of AIMPl and pancreas containing high concentrations of AIMPl, and eluted them through sizing chromatography.

Mice tissues (lung and pancreas) were isolated, washed with cold PBS twice and suspended in lysis solution containing 1OmM HEPES pH 7.6 , 10 mM KCl, 1.5 mM MgCl₂, 0.5 ttiM EGTA, 10 mM NaF, 1 mM PMSF and protease inhibitor cocktail (Roche) . The tissues were then lysed using Dounce homogenizer and the lysates were centrifuged at 14,000 rpm for 15 min. The supernatants were mixed with the equal volume of 10 mM HEPES buffer (pH 7.5) containing 150 mM KCl, 1.5 mM MgCl₂, 0.5 mM EGTA, 10 mM NaF, 1 mM PMSF, protease inhibitor cocktail (Roche) . The samples were filtered through 0.22 μm membrane and the proteins were concentrated to 9 mg/ml using viva spin. Then, the proteins were subjected to gel filtration chromatography using sephacryl S-300 (high resolution with the separation range of 10-1500 kDa) in FPLC (Pharmacia) . The eluted fractions were subjected to Western blotting with the antibodies specific to each of the components for the multi-tRNA synthetase complex.

As a result, Although AIMPl was mainly eluted in the complex-bound form in lung with other components such as EPRS (glutamyl -prolyl-tRNA synthetase) and RRS (prolyl -tRNA synthetase) , it was eluted in both the complex-bound and free forms in pancreas, where AIMPl levels were high (see Fig. 2) .

<l-3> Determination of cell type responsible for the enrichment of AIMPl in pancreas

Since the pancreas is an exo- and endocrine gland composed of different types of secretory cells, the present inventors determined the type of cells responsible for the enrichment of AIMPl in the pancreas by immunohistochemical staining and immunoGold staining.

The immunohistochemical staining was preformed by following method.

Pancreas were isolated from mice and fixed in 10% formaldehyde for 24 h. The fixed tissues were dehydrated and embedded in paraffin. We then sliced the embedded tissues with microtome (Leica) , mounted them on silane-coated slides, dewaxed and rehydrated. The slides were equilibrated with PBS and blocked with PBS containing 0.1% Tween 20 and 1% skim milk for 1 h at room temperature, and reacted with specific antibodies against AIMPl, glucagon (Sigma) , insulin (Sigma) at room temperature for 2 h. We washed the slides with PBS containing 0.1% tween 20 and incubated them at 37^°C for 1 h with fluorescein isothiocyanate (FITC) - or Rhodamine-conjugated secondary antibody, or biotin- conjugated secondary antibody. The nuclei were counterstained with propidium iodide (10μg/ml) for 10 min, and the slides were examined under the confocal immunofluorescence microscope (μ-Radiance; BioRad) . Biotin- conjugated secondary antibodies were captured with streptavidin-HRP and developed with QEC solution (Zymed) . The nuclei were counterstained with Meyer's hematoxilin.

The immunoGold staining was preformed by follwing method. Pancreases were dissected from mouse in 10 mM PBS

(pH 7.4) and fixed in 2% paraformaldegyde-2.5% glutaraldegyde mixture in 10 mM PBS at 4°C for 2 h. After being washed with PBS three times at 30 min intervals, the tissues were dehydrated in ethanol . The dehydrated tissues were then embedded in an LR White (London Resin White) in gelatin capsules. For electron microscopic examination, the embedded tissues were thin-sectioned using an ultramierotome (LKB), and attached to nickel grids. After incubation with PBSTB (10 mM PBS containing 0.05% Tween-20 and 1% BSA) for 10 min, the grids were reacted with rabbit anti-AIMPl or mouse anti-glucagon antibody diluted 50-fold with PBSTB and then washed six times with PBSTB to remove nonspecifically bound antibodies. The grids were reacted with 20 nm protein A-conjugated colloidal gold (Sigma) probes diluted 25-fold with PBSTB (Gosselin E. J. et al . , J^". Histochem. Cytochem,

32, 799-804, 1984; Bendayan, M et al . , J. Histochem.

Cytochem. 34, 569-575, 1986). After being washed with PBST containing 10 mM PBS and 0.05% Tween-20, and distilled water three times, the labeled sections were contrasted with 2% uranyl acetate and observed under an electron microscope

(JEOL) at 80 kV.

The result of immunohistochemical staining showed that the AIMPl was specifically localized to the peripheral area of the pancreatic islets (see Fig 3) . And the AIMPl was highly concentrated in α cell along with glucagon but no in βcell(see Fig 4).

Also, the result of immunoGold staining showed that the AIMPl was enriched in the secretory vesicles of the α cell of pancreatic islet (see Fig 5) .

Example 2 : AIMPl secretion by the change of glucose concentration

<2-l> Secretion of AIMPl by pancreatic stimulation through the cardiac perfusion of the various concentrations of glucose

The solution with different glucose concentration was introduced into mice by means of cardiac perfusion, and then pancreas was isolated and incubated in the medium to check whether AIMPl is secreted by the change of glucose concentration .

12 weeks old male mice (C57BL/6) were anesthetized with an intraperitonial injection of 2.5% avertin (100

1/1Og) . The abdomen was opened with sterile scissors and injected 26 gauge needle filled with DMEM medium into left ventricle. We cut the vena cava and perfused the cardiac with the various concentrations of glucose solutions (50, 75, 100, 200, 400mg/dL) at the flow rate of 10 ml/min for 5 min. The pancreas was isolated and washed with PBS containing 1% streptomycin/penicillin, and incubated on the conditioned medium for 2 h in CO₂ incubator at 37"C. The medium was harvested, and proteins were precipitated by addition of 10% TCA at room temperature for 2 h, and centrifuged at 16,000 g for 15 min. The protein extracts were separated by 10% SDS- PAGE and blotted with anti- AIMPl antibody by the same manner as in Example <1-1>.

As a result, AIMPl was secreted to the medium at glucose concentrations below than lOOmg/dL, but not above (see Fig 6) , indicating that AIMPl is secreted upon low glucose concentrations.

<2-2> AIMPl secretion from pancreatic alpha cells according to the glucose concentrations To confirm these results, the present inventors cultured a pancreatic αcell line, aTCl clone 9, at high (450mg/dL) and low (75mg/dL) glucose concentrations, harvested the medium at different time points and checked the AIMPl secretion by Western blotting.

The aTCl clone 9 was purchased from ATCC (CRL-2350 and the cells were maintained in modified DMEM according to the recommendation of ATCC. The cells were plated on 60-mm dish and cultured for 4 days. The medium was exchanged with serum-free DMEM containing high glucose (450 mg/dL) or low glucose (75 mg/dL) , the medium was harvested at time interval and centrifuged at 3,000 x g for 15 min, 16,000 x g for another 15 min to remove contaminants. Proteins were precipitated from the supernatants with 10% TCA for 2 h at room temperature, and it was centrifuged at 16,000 x g for 15 min, pellet was harvested and resuspended with 10 mM Tris-HCl (pH 8.3), loaded into 10% SDS-PAGE and transferred to PVDF membrane for immunoblotting with anti -AIMPl antibody by the same manner as in. Example <1-1>.

As a result, AIMPl was specifically secreted to medium at low glucose concentrations (75mg/dL) with no change in its expression (see Fig 7) .

Example 3: Effect of AIMPl on glucagon secretion aTCl clone 9 cells were cultured with modified Dulbecco's Modified Eagle's Medium containing 4 mM L- glutamine, 3.0 g/L glucose, 1.5 g/L sodium bicarbonate, 15 mM HEPES, 0.1 mM non-essential amino acids, 0.02% bovine serum albumin, 10% heat-inactivated dialyzed fetal bovine serum and 1% penicillin-streptomycin in humidified 5% CO₂ incubator. Then the aTCl clone 9 was seeded on 6-well plates, cultured for 4 days, and changed with serum-free medium. The cells were treated with 100 nM of AIMPl and the medium was harvested at the indicated times (0, 5, 10, 15, 30, 60, 90 min) . The secreted glucagon was quantified using a glucagon RIA kit (LINCO Research) following the manufacturer's instruction.

As a result, the glucagon secretion from pancreatic alpha cells was stimulated by AIMPl. That is, the glucagon secretion was enhanced about 3 -fold at 15 min after AIMPl infusion and subsequently declined to the background level (see Fig 8) .

Example 4: The effect of AIMPl on the blood levels of hormones and metabolites related to glucose metabolism

SD (250-30Og, male) rats were purchased and maintained at 12 h dark/12 h light cycle at 22^°C. The rats were fasted for 5 h to perform the infusion experiment through the cannulation of tail vein. First, the AIMPl was infused 3.6 mg/kg by bolus injection for 1 min and blood was harvested at indicated time point for metabolic analysis. The blood was centrifuged at 2,000 g for 20 min. And plasma was harvested and stored at -70^°C. And then the plasma level of glucagon, insulin, glucose, lactate, free fatty acid and glycerol was measured using their specific quantification kits.

The glucagon was quantified using glucagon RIA kit (LINCO Research) following the manufacturer's instruction. The insulin was measured using ELISA kit (Lonco Research) , the glucose was measured using Blood Glucose Monitor kit (Roche) . The lactic acid concentration was measured using Yellow Spring Instruments, the free fatty acid was measured using Nefazyme kit, the glycerol was measured using Sigma kit.

As a result, the plasma glucagon level was increased about 3-fold after the AIMPl infusion, whereas the insulin level was not affected. Also, AIMPl raised the plasma glucose level about 2 -fold but didn't induce any change in the lactate concentration. Blood glucose showed the peak at 60min and then gradually declined. Free fatty acid and glycerol showed the peak in 30 min after AIMPl infusion and then returned to basal level (see Fig 9) . The AIMPl induced increase of glucose prior to glucagon enhancement suggests that it could directly control the glucose level in addition to its stimulation of glucagon secretion.

Example 5: The effect of AIMPl on glucose and free fatty acid uptake

The metabolic action of AIMPl may be achieved in a couple of different ways. First, it could block the uptake of glucose and free fatty acid in peripheral tissues. This possibility was checked in adipocyte, myocyte and hapatoma .

Pre-adiopocyte 3T3-L1 (ATCC CL-173) cells were cultured at DMEM containing 10% FBS, 1% penicillin/streptomycin at humidified 5% CO2 incubator. The cells were seeded onto 12 multi-well plates, cultured to confluency, and maintained for 2 days. The medium was exchanged with the differentiation medium, DMEM containing 0.5mM 3-isobutyl-l-methylxantine, lμM dexamethasone, lOμg/ml bovine insulin, the cells were cultured 2 days and replaced every other days for 6 days.

Myocyte C2C12 cells (ATCC CRL-1772) were cultured at DMEM containing 10% FBS and 1% penicillin/streptomycin, and the medium was changed with DMEM containing 2% horse serum. The cells were cultured and the medium was changed every other day for 5 days. Hepatoma HepG2 cells (ATCC HB-8065) were cultured in the MEM containing 10% FBS and 1% penicillin-streptomycin in humidified 5% CO₂ incubator.

Glucose uptake assay was performed by known method (Kase, E. T et al . , Diabetes, 54, 1108-1115, 2005).

Briefly, the cells were starved in serum-free medium for 2 h and treated with AIMPl for 30 min. [U-¹⁴C] D-glucose

(lμCi/well) was added and quantified the incorporation rate using liquid scintillation counter (LKB) . 1OnM of glucagon was used as positive control.

Fatty acid uptake assay was performed by following method. Myocytes were stimulated with the indicated concentration of AIMPl in serum-free medium for 30 min, and [³H] -BSA-palmitate (1 μCi/well) was treated for 4min. For adipocyte, the culture medium was changed with serum-free medium and the cells were incubated for 2h. AIMPl was treated for 30 min and the incorporation of [³H] -BSA- palmitate (1 μCi/well) was induced for 4 min. The cells were washed with HBS and lysed with IN NaOH. Radioactivity was quantified using a liquid scintillation counter (LKB) .

As a result, AIMPl didn't affect the uptake of [¹⁴C]

D-glucose and [³H] palmitic acid in adiopocytes and muscle cells (see Fig 10) . However, AIMPl inhibited the uptake of

D-glucose in HepG2 although not the uptake of fatty acid (see Fig 11) . Since [¹⁴C] D-glucose can be metabolized to different metabolites within the cells, we also monitored the glucose uptake using [¹⁴C] D-deoxyglucose and observed a similar result (data not shown) .

Example 6 : The effect of AIMPl on glycogenolysis

For the glucose secretion assay, the present inventors activated glycogen storage in HepG2 by insulin treatment in the presence of [U-¹⁴C] D-glucose. We then treated the cells with AIMPl to determine whether it enhances disgorgement of glucose through glycogenolysis.

HepG2 was maintained in the MEM containing 10% FBS and 1% penicillin/streptomycin in humidified 5% CO₂ incubator. The HepG2 cells were seeded onto a six-well plate and cultured for glycogenolysis assay. The medium was replaced with serum-free MEM containing 25 mM glucose, 1OnM insulin,

[U-¹⁴C] D-glucose (2 μCi/well) and cultured for 16-18h. The cells were washed with HBS and incubated with glucose-free

DMEM containing glucagon (1OnM) or AIMPl (10, 20, 50, 100 nM) for 4 h. For the glucose release assay, the medium was harvested and precipitated with 10% TCA and the supernatant was taken for the counting of the released [U-¹⁴C] D- glucose . For cellular glucose assay, the cells were washed with HBS and lysed with IN NaOH. Radioactivity was quantified by using a liquid scintillation counter (LKB) , and the cellular concentration of [U-¹⁴C] D-glucose was calibrated with the protein concentration.

As a result, AIMPl increased [U-¹⁴C] D-glucose levels in the medium about 3 -fold in a dose-dependent manner whereas the intracellular concentration of [U-¹⁴C] D- glycogen decreased about 20% (see Fig 12) . These data suggest that AIMPl would induce glycogenolysis to supply glucose to blood while inhibiting glucose uptake in hepatocytes .

Example 7: The effect of AIMPl on lipolysis The present inventors checked whether AIMPl stimulates lipolysis in differentiated adipocyte by measuring the secretion of fatty acid and glycerol because most of them are degradation products of triglyceride from adipose tissue. The present inventors induced storage of [³H] palmitic acid into triglyceride by treating the differentiated adipocytes with insulin. Then the cells were treated with different concentrations of AIMPl for 8h and measured [³H] palmitic acid levels in the culture medium and cells .

Pre-adipocyte 3T3-L1 was cultured with DMEM containing 10% FBS, 1% penicillin/streptomycin at humidified 5% CO₂ incubator. The cells were seeded onto 12 multi-well plates, cultured to confluency, and maintained for 2 days. The medium was replaced with the differentiation medium (DMEM containing 0.5mM 3-isobutyl-l-methylxanthine, iμM dexamethasone, 10μg/ml bovine insulin) and cultured for 2 days and replaced every other days for 6 days. The cell were washed with PBS and cultured with serum-free DMEM containing [³H] -BSA-palmitate (lμCi/ml) and 1OnM bovine insulin. The cells were washed with PBS and cultured with serum-free DMEM containing glucagon or AIMPl for 8 h. The medium was harvested to measure the released palmitate, and the cells were washed with PBS and lysed with 0.5 N NaOH. [³H] -palmitate was quantified by using a liquid scintillation counter, and cellular concentration of [³H] - palmitate was calibrated with the protein concentration.

As a result, the concentration of [³H] palmitic acid increased in the medium about 4 -fold by AIMPl treatment whereas the cellular [³H] palmitic acid level decreased about 10% (see Fig 13), suggesting that the increase of fatty acid in the blood upon the infusion of AIMPl resulted from the direct induction of lipolysis of triglyceride (TAG) in the adipocytes.

Example 8: Phβnotypes related to glucose metabolism in AIMPl-deficient mice <8-l> Concentration of plasma glucose, free fatty acid and glycogen in AIMPl-deficient mice

The present inventors examined the related phenotypes in AIMPl-deficient mice. AIMPl-deficient mice were prepared using the gene trap method (Cecconi, F. & Meyer, B. I., FEBS Lett., 480:63-71, 2000) . First, the gene trap vector, VICTR20 (Lexicon Genetics, USA) was used to mutate the genomic DNA of SvEvBrd mice (Lexicon Genetics, USA) . The mutated genomic DNA was introduced into the embryonic stem cells derived from 129/SvEvBrd mice (Omnibank) to generate the mutant library. In the library, the clone containing AIMP-I gene disrupted by the insertion of the gene trap vector was screened and called ^VOST58507'. The clone was used to generate the heterozygous C57/BL6 mice (Samtako) by the standard method of Lexicon Genetics. The mating of the heterozygous mice generated 16 of wild type (AIMP1^+/+) , 53 of heterozygous mutant mice (AIMPl^+/~) and 28 of homozygous mutant mice

(AIMP1^'Λ) .

The plasma glucose (n = 9) and free fatty acid levels (n = 5) were measured by the same manner as in Example 4.

The glycogen concentrations in liver were measured by following method. The liver was sliced 50mg, added to 30% KOH solution, and then heated for 30 min. Then we added 60% ethanol and 0.3% LiBr to the resultants, cultured them on the ice for 30 min and centrifuged at 5,000 rpm for 15 min at 4°C. The supernatants were removed and then 60% ethanol was added to the resultants. And we also centrifuged by the same manner and removed the supernatants. This process was performed twice. And we added 2mg amyloglucosidase to the resultants, cultured at 55 °C for 1 hour and quantified glycogen concentrations using GAGO-20 (Sigma) .

As a result, the plasma levels of glucose and free fatty acid were slightly reduced in AIMPl-/- compared with those in AIMP1+/+ mice. Also AIMPl-/- mice had a little higher glycogen content in the liver compared with the AIMP1+/+ mice (see Fig 14) . Although the metabolite differences between the mutant and wild type mice are not dramatic, these phenotypes of the AIMPl-deficient mice are consistent with the prediction based on the hormonal activity of AIMPl.

<8-2> Immunohistochemical staining of pancreatic islet in AIMPl-deficient mice

The insulin and glucagon levels in pancreatic islets were compared between AIMP1^+/+ and AIMP1^"/" mice by inmmunohistochemical staining. The immunohistochemical staining was preformed by the same manner as in Example <1- 3>.

As a result, it showed that insulin and glucagon are present at normal levels in AIMPl-/- mice, suggesting that AIMPl would not regulate the expression levels of glucagon and insulin (see Fig 15) .

<8-3> Blood glucose level of AIMPl- deficient mice upon fasting AIMPl ^^'^=9) or AIMP^+/+ mice (n=9) were fasted for the different times (0, 6, 12, 24h) and blood glucose levels were measured by the same manner as in example 4.

As a result, upon fasting the blood glucose concentration was rapidly decreased below 70mg/dL in AIMPl^^" mice, whereas AIMP1^+/+ mice maintained a glucose above 90mg/dL (see Fig 16) .

<8-4> intraperitoneal glucose tolerance test of AIMPl- deficient mice AIMP1^+/+ (n=9) and AIMP^'Λ mice (n=9) between 12 week and 16 week were fasted for 14h. At time 0, blood glucose was measured immediately and 20% sterile glucose solution was injected intraperitonially to reach the concentration of 2g/kg body weight. Bloods were harvested at the different time points (15, 30, 60, 90, 150 tnin) and glucose levels were measured by the same manner as in Example 4.

AIMPl-/- mice showed faster removal of glucose from the blood than AIMP^+/+ mice (see Fig 17) .

Industrial Applicability

As described above, the inventive AIMPl has the activity of glucagon-like hormone. Accordingly, the inventive AIMPl can be effectively used for controlling glucose level in a subject, or preventing and treating hypoglycemia or disease associated with hypoglycemia in a subject .

Claims

Claims :

1. A method for controlling glucose level in a subject, which comprises administering to a subject in need thereof an effective amount of one selected from the group consisting of:

(c) an isolated nucleic acid encoding the polypeptide

(a) or (b) .

2. The method of claim 1, wherein the controlling glucose level is increasing glucose level.

3. The method of claim 1, wherein the polypeptide

(b) is selected from the group consisting of SEQ ID NO : 2 to SEQ ID NO: 4.

4. The method of claim 1, wherein the nucleic acid

(c) is selected from the group consisting of SEQ ID NO : 5 to SEQ ID NO: 9.

5. A method for preventing or treating hypoglycemia, which comprises administering to a subject in need thereof an effective amount of one selected from the group consisting of: (a) an isolated polypeptide having the amino acid sequence set forth in SEQ ID NO: 1;

(b) an isolated polypeptide having the amino acid sequence homology of at least 70% to the polypeptide (a) ; and (c) an isolated nucleic acid encoding the polypeptide

(a) or (b) .

6. The method of claim 5, wherein the polypeptide

(b) is selected from the group consisting of SEQ ID NO: 2 to SEQ ID NO: 4.

7. The method of claim 5, wherein the nucleic acid

(c) is selected from the group consisting of SEQ ID NO: 5 to SEQ ID NO: 9.

8. A method for preventing or treating disease associated with hypoglycemia, which comprises administering to a subject in need thereof an effective amount of one selected from the group consisting of: (a) an isolated polypeptide having the amino acid sequence set forth in SEQ ID NO: 1;

(c) an isolated nucleic acid encoding the polypeptide (a) or (b) .

9. The method of claim 8, wherein the disease is selected from the group consisting of diabetes mellitus, endocrine disorders, dyshepatia, renal failure and pancreatic cancer.

10. The method of claim 8, wherein the polypeptide (b) is selected from the group consisting of SEQ ID NO: 2 to

SEQ ID NO : 4.

11. The method of claim 8, wherein the nucleic acid (c) is selected from the group consisting of SEQ ID NO : 5 to SEQ ID NO: 9.

12. A composition for controlling glucose level in a subject, which comprises as an effective ingredient one selected from the group consisting of: (a) an isolated polypeptide having the amino acid sequence set forth in SEQ ID NO: 1;

(c) an isolated nucleic acid encoding the polypeptide (a) or (b) .

13. The composition of claim 12, wherein the controlling glucose level is increasing glucose level.

14. The composition of claim 12, wherein the polypeptide (b) is selected from the group consisting of SEQ ID NO: 2 to SEQ ID NO: 4.

15. The composition of claim 12, wherein the nucleic acid (c) is selected from the group consisting of SEQ ID NO: 5 to SEQ ID NO : 9.

16. A composition for preventing or treating hypoglycemia, which comprises as an effective ingredient one selected from the group consisting of:

(a) an isolated polypeptide having the amino acid sequence set forth in SEQ ID NO: 1; (b) an isolated polypeptide having the amino acid sequence homology of at least 70% to the polypeptide (a) ; and

(c) an isolated nucleic acid encoding the polypeptide (a) or (b) .

17. The composition of claim 16, wherein the polypeptide (b) is selected from the group consisting of SEQ ID NO: 2 to SEQ ID NO: 4.

18. The composition of claim 16, wherein the nucleic acid (c) is selected from the group consisting of SEQ ID NO: 5 to SEQ ID NO : 9.

19. A composition for preventing or treating disease associated with hypoglycemia, which comprises administering to a subject in need thereof an effective amount of one selected from the group consisting of:

(c) an isolated nucleic acid encoding the polypeptide (a) or (b) .

20. The composition of claim 19, wherein the disease is selected from the group consisting of diabetes mellitus, endocrine disorders, dyshepatia, renal failure and pancreatic cancer.

21. The composition of claim 19, wherein the polypeptide (b) is selected from the group consisting of SEQ ID NO: 2 to SEQ ID NO: 4.

22. The composition of claim 19, wherein the nucleic acid (c) is selected from the group consisting of SEQ ID NO: 5 to SEQ ID NO: 9.

23. Use of one selected from the group consisting of:

(b) an isolated polypeptide having the amino acid sequence¹ homology of at least 70% to the polypeptide (a) ; and

(c) an isolated nucleic acid encoding the polypeptide (a) or (b) for the preparing a medicament for treating hypoglycemia .

24. Use of one selected from the group consisting of:

(c) an isolated nucleic acid encoding the polypeptide (a) or (b) for the preparing a medicament for treating disease associated with hypoglycemia.