Novel blood sugar controller and method of screening the same
The present invention provides an impaired glucose tolerance ameliorating drug and a therapeutic drug for lifestyle-related diseases, particular an antidiabetic drug, which contain a CXCR3 agonist as an active ingredient; a hypoglycemia ameliorating drug, a therapeutic drug for insulinoma or an anti-obesity drug containing a CXCR3 antagonist as an active ingredient; a method of screening for a new CXCR3 ligand using CXCR3 and a known CXCR3 ligand; a method of screening a CXCR3 ligand, which uses a co-expression system of CXCR3 and a coupling G protein; and a diagnostic method for type II diabetes, which includes detecting an amount of a CXCR3 ligand expressed in a biological sample.
1 . A blood glucose and/or insulin secretion regulator comprising a CXCR3 ligand as an active ingredient.
2 . An impaired glucose tolerance ameliorating drug comprising a CXCR3 agonist as an active ingredient.
3 . The impaired glucose tolerance ameliorating drug of claim 2 , wherein the CXCR3 agonist is at least one selected from the group consisting of IP-10, Mig, I-TAC, BCA-1, modifications thereof and prodrugs thereof.
4 . The impaired glucose tolerance ameliorating drug of claim 2 , wherein the CXCR3 agonist is at least one selected from the group consisting of IP-10, Mig, I-TAC, modifications thereof and prodrugs thereof.
5 . The impaired glucose tolerance ameliorating drug of claim 2 , which is a therapeutic drug for lifestyle-related diseases.
6 . The impaired glucose tolerance ameliorating drug of claim 2 , which is a therapeutic drug for diabetes.
7 . A hypoglycemia ameliorating drug comprising a CXCR3 antagonist as an active ingredient.
8 . A therapeutic drug for a disease that can be ameliorated by suppression of insulin secretion, which comprises a CXCR3 antagonist as an active ingredient.
9 . An anti-obesity drug comprising a CXCR3 antagonist as an active ingredient.
10 . A method of screening a CXCR3 ligand, which comprises bringing a test sample into contact with CXCR3 or a fragment thereof to which a ligand can bind, and selecting a compound that binds to said receptor or a fragment thereof.
11 . A method of screening a CXCR3 ligand, which comprises bringing a known ligand into contact with CXCR3 or a fragment thereof to which a ligand can bind, in the presence and absence of a test substance, and comparing the binding activity of said receptor or fragment thereof and the known ligand under both conditions.
12 . The screening method of claim 10 , wherein CXCR3 or a fragment thereof to which a ligand can bind is provided in the form of a lipid bilayer embedding same.
13 . A method of screening a CXCR3 ligand, which comprises comparing, in a reaction system comprising a CXCR3-containing lipid bilayer and an α-subunit of a G protein capable of being coupled with CXCR3, the GDP-GTP exchange reaction of said subunit or the cell stimulating activity of said G protein, in the presence and absence of a test substance.
14 . The screening method of claim 13 , wherein the reaction system is:
(i) a host eukaryotic cell transfected with an expression vector comprising a DNA that encodes CXCR3 and with an expression vector comprising a DNA that encodes the α subunit of a G protein capable of being coupled with CXCR3, (ii) a host eukaryotic cell transfected with an expression vector comprising a DNA that encodes a polypeptide consisting of CXCR3 and the α subunit of a G protein capable of being coupled with CXCR3 fused to the C-terminus side of CXCR3, (iii) a host animal cell that endogeneously expresses a G protein capable of being coupled with CXCR3, which is transfected with an expression vector comprising a DNA that encodes CXCR3, (iv) an animal cell that endogenously expresses CXCR3 and a G protein capable of being coupled with CXCR3, a homogenate of the cell, or a membrane fraction derived from the cell.
15 . The screening method of claim 14 , which comprises adding a GTP analogue to the reaction system in the presence and absence of a test substance, and comparing the binding of the α-subunit of the G protein capable of being coupled with CXCR3 and the GTP analogue under both conditions.
16 . The screening method of claim 14 , wherein the α-subunit of the G protein capable of being coupled with CXCR3 comprises a region that interacts with adenylate cyclase.
17 . The method of claim 16 , which comprises adding ATP to the reaction system in the presence and absence of a test substance, and comparing adenylate cyclase activity under both conditions.
18 . The method of claim 16 , which comprises comparing the cAMP amount in the cells of (i) to (iv) above, in the presence and absence of a test substance.
19 . The screening method of claim 14 , wherein the α-subunit of the G protein capable of being coupled with CXCR3 comprises a region that interacts with phospholipase Cβ.
20 . The screening method of claim 19 , which comprises adding phosphatidylinositol-4,5-diphosphate to the reaction system in the presence and absence of a test substance, and comparing phospholipase Cβ activity under both conditions.
21 . The screening method of claim 19 , which comprises comparing the amount of intracellular calcium ions in the cells of (i) to (iv) in the presence and absence of a test substance.
22 . The screening method of claim 16 , which comprises comparing the expression level of a reporter gene under the control of a promoter region comprising the cAMP-responsive element in the cells of (i) to (iv), which further comprise an expression vector containing said reporter gene, in the presence and absence of a test substance.
23 . The screening method of claim 19 , which comprises comparing the expression level of a reporter gene under the control of a promoter region comprising the TPA-responding element in the cells of (i) to (iv), which further comprise an expression vector containing said reporter gene, in the presence and absence of a test substance.
24 . The screening method of claim 13 , which is performed in the co-presence of a known ligand.
25 . A blood glucose and/or insulin secretion regulator comprising a CXCR3 ligand selected by the method of claim 10 as an active ingredient.
26 . An impaired glucose tolerance ameliorating drug comprising a CXCR3 agonist selected by the method of claim 10 as an active ingredient.
27 . The impaired glucose tolerance ameliorating drug of claim 26 , which is a therapeutic drug for lifestyle-related diseases.
28 . The impaired glucose tolerance ameliorating drug of claim 26 , which is a therapeutic drug for diabetes.
29 . A hypoglycemia ameliorating drug comprising a CXCR3 antagonist selected by the method of claim 10 as an active ingredient.
30 . A therapeutic drug for a disease that can be ameliorated by suppression of insulin secretion, which comprises a CXCR3 antagonist selected by the method of claim 10 as an active ingredient.
31 . An anti-obesity drug comprising a CXCR3 antagonist selected by the method of claim 10 as an active ingredient.
32 . A diagnostic method for type II diabetes, which comprises measuring a CXCR3 ligand or a transcript of a gene of said ligand in a biological sample using an antibody possessing specific affinity for the physiological ligand for CXCR3 or a nucleic acid that encodes said ligand or a nucleic acid hybridizable with said nucleic acid under stringent conditions.
33 . A diagnostic reagent for type II diabetes, which comprises an antibody possessing specific affinity for a physiological ligand for CXCR3 or a nucleic acid that encodes said ligand or a nucleic acid hybridizable with said nucleic acid under stringent conditions.