| Project/Area Number |
18390024
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biological pharmacy
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| Research Institution | Kyoto University |
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Principal Investigator |
HIRASAWA Akira Kyoto University, Graduate School of Pharmaceutical Sciences, Associate Professor (70242633)
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| Co-Investigator(Kenkyū-buntansha) |
AWAJI Takeo Tokyo Women's Medical University, School of Medicine, Lecturer (60297546)
HAYANO Toshiya Ritsumeikan University, College of Information Science and Engineering, Professor (90332303)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥17,060,000 (Direct Cost: ¥15,500,000、Indirect Cost: ¥1,560,000)
Fiscal Year 2007: ¥6,760,000 (Direct Cost: ¥5,200,000、Indirect Cost: ¥1,560,000)
Fiscal Year 2006: ¥10,300,000 (Direct Cost: ¥10,300,000)
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| Keywords | Proteome / signal transduction / Microarray / pharmaceutical sciences / genome / オーファン受容体 / 脂肪酸 / 分泌 / ペプチド / 脂肪酸受容体 / 質量分析 |
|---|
| Research Abstract |
Agonist activation of a G protein-coupled receptor (GPCR) results in the redistribution of the receptor protein away from the cell surface into internal cellular compartments through a process of endocytosis known as internalization. We examined whether the ligand-mediated internalization of a GPCR can be exploited for pharmacological evaluations. We acquired fluorescent images of cells expressing GFP-labeled GPCRs and evaluated the ligand-mediated internalization quantitatively by image processing. The rank order of receptor internalization potency for a variety of agonists and antagonists specific to each receptor corresponded well with that previously observed in ligand binding studies. In addition to chemical ligand-induced internalization, this cell-based fluorescence imaging system successfully monitored the internalization of the proton-sensing GPCR TDAG8, and that of the free fatty acid-sensitive GPCR GPR120. The results show. That monitoring receptor internalization can be a u
… More
seful approach for pharmacological characterization of GPCRs and in fishing for ligands of orphan GPCRs.
We have recently found that GPR120, which is abundantly expressed in intestine, functions as a receptor for unsaturated long-chain free fatty acids (FFAs) and that GPR120 stimulation promotes the secretion of glucagons-like peptide-1 (GLP-1) in the mouse. The ingestion of fat induces secretion of the gut peptide hormone cholecystokinin (CCK). In this study, we examined whether these FFA receptors mediate-lipid-induced CCK and other peptide release in the mouse. We first observed that intra-gastric administration of long-chain FFAs increased plasma CCK levels. Using mouse enteroendocrine STC-1 cells as a model system, we further studied the mechanism of this FFA induced CCK secretion_ Long-chain FFAs promoted CCK secretion from STC-1 cells, which was abolished either by removal of extracellular Ca2+or by the L-type Ca^<2+>channel blacker nicardipine. Furthermore, this FFA-induced CCK secretion was specifically inhibited by transfection of GPR120-specific, but not GPR40-specific, short hairpin RNA. These results indicate that long-chain FFAs induce CCK secretion through GPR120-coupled Ca^<2+>signaling. Less
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