1999 Fiscal Year Final Research Report Summary
Differentiation of Factor in Pancreatic B cells : Pax4
| Project/Area Number |
10671057
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Metabolomics
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| Research Institution | Chiba University |
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Principal Investigator |
HASHIMOTO Naotake Chiba University assistant prof., 医学部, 講師 (00272328)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Yoshifumi Chiba University assistant, 医学部, 助手 (20302549)
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| Project Period (FY) |
1998 – 1999
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| Keywords | pancreatic B cell / Pax-4 / Insulin Release / Diabetes Mellitus |
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| Research Abstract |
Molecular cloning of rat Pax4 cDNA from a rat insulinoma cell line, RINm5F, library by PCR-based cloning strategy revealed four isoforms of the protein. Analysis of tissue disrtibution using Northern blotting and RT-PCR showed specific expression of Pax4 mRNA in pancreatic islets and RIN cells. RT-PCR confirmed that the mRNAs of four isoforms are expressed in RIN cells. These Pax4 variants may regulate the transcriptional activity of Pax4 during the development of pancreatic islets. Cytokines induce apoptosis in pancreatic beta-cells, but the exact mechanisms and sequence of events are not clear. We investigated a role for tumor necrosis factor-α (TNF-α) in the apoptosis of beta-cells. Using the ribonuclease protein assay and the reverse transcriptase-polymerase chain reaction method, we confirmed that tumor necrosis factor receptor 1 (TNFR1), TNFR1-associated death domain protein (TRADD), Fas receptor-associated intracellular protein with death domain (FADD) and FADD-like ICE(FLICE) were expressed in the pancreatic beta-cell line, MIN6 cells. Fluorescent microscopic examination using Hoechst 33342 dye demonstrated that TNF-α induced time- and dose-dependent apoptotic nuclear changes in these beta-cells. In situ end-labeling of DNA analysis and agarose gels electrophresis revealed that 10 nM TNF-αgenerated characteristic apoptotic DNA fragments. In addition, C2- and natural ceramides dispersed in a solvent mixture of ethanol and dodecane induced characteristic features of apoptosis in MIN6 cells, mimicking TNF-induced DNA damage. We also determined endosomal ceramide production after TNF-α (10 nM) treatment in MIN6 cells using diacyblycerol kinase assay. These results suggest that TNF-α can cause apoptosis in pancreatic beta-cells through TNFR1-linked apoptotic factors, TRADD, FADD and FLICE, and that TNF-induced ceramide production may be involved in the pathways.
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Research Products
(12 results)
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[Publications] Tokuyama, Y., Yagui, K., Sakurai K., Hashimoto, N., Saito, Y., and Kanatsuka, A.: "Molecular cloning of rat pax 4 : identification of four isoforms in rat insulinoma cell."Biochem. Biophys. Res. Commun.. 248. 153-156 (1998)
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「研究成果報告書概要(欧文)」より
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[Publications] Yagui, K., Shimada, F., Mimura, M., Hashimoto, N., Suzuki, Y., Tokuyama, Y., Nata, K., Tohgo, A., Ikehata, F., Takasawa, S., Okamoto, H., Makino, H., Saito, Y., and Kanatsuka, A.: "A missense mutation in the CD 38 gene, a novel factor for insulin secretion : association with type II diabetes mellitus in Japanese subjacts and evidence of abnormal function when expressed in vitro."Diabetologia. 41. 1024-1028 (1998)
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[Publications] Toyoda, M., Hashimoto, N., Tokita, K., Goldstein, BJ., Yokosuka, O., Kanatsuka, A., Suzuki, Y., Saito, Y.: "Increased activity and expression of MAP kinase in HCC model rats induced by 3'-methyl-4-dimethylaminoazobenzene."Journal of hepatology. 31. 725-733 (1998)
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[Publications] Ishizuka, N., Yagui, K., Tokuyama, K., Yamada, K., Suzuki, Y., Miyazaki, J., Hashimoto, N., Makino, H., Saito, Y., and Kanatsuka, A.: "Tumor necrosis factor alfa signaling pathway and apoptosis in pancreatic beta cells."Metabolism. 48(12). 1485-92 (1999)
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「研究成果報告書概要(欧文)」より
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[Publications] Kuramoto N., Iizuka T., Ito H., Yagui K., Omura M., Nozaki O., Nishikawa T., Tsuchida H., Makino H., Saito Y., and Kanatsuka A.: "Effect of ACE gene on diabetic nephropathy in NIDDM patients with insulin resistance."Am J of kidney diseases.. 33. 276-281 (1999)
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「研究成果報告書概要(欧文)」より
