| Project/Area Number |
13671184
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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 | Shiga University of Medical Science |
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Principal Investigator |
HANEDA Masakazu Shiga Univ. of Medical Science, Associate Professor, 医学部, 講師 (60164894)
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| Co-Investigator(Kenkyū-buntansha) |
KOYA Daisuke Shiga University of Medical Science, Associate Professor, 医学部, 助手 (70242980)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2001: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | oxidative stress / PKC-β / NADPH oxidase / diabetic nephropathy / mesangial cells / HO-1 / 糖尿病 / 糸球体 / NADPH oxidase / PKC / 腎糸球体 / heme oxygenase-1 |
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| Research Abstract |
Oxidative stress is implicated to play an important role in the development of diabetic vascular complications, including diabetic nephropathy. In this study, we examined to determine whether oxidative stress is enhanced in the diabetic glomeruli and the role of protein kinase C (PKC)-β activation in regulating the NADPH oxidase, the main source of reactive oxygen species (ROS). The mRNA expression of antioxidant enzymes such as catalase, glutathione peroxidase, and CuZn-superoxide dismutase was not altered in glomeruli of streptozotocin (STZ)-induced diabetic rat at 2 and 4 weeks of age. In contrast, the mRNA expression of heme oxygenase-l (HO-1) was enhanced in diabetic glomeruli. A treatment of insulin and vitamin E normalized the expression of HO-1 in diabetic glomeruli. Immunohistochemical analysis revealed that the enhanced expression of HO-1 is preferentially increased in glomerular cells such as mesangial cells and epithelial cells. Urinary 8-hydroxydeoxyguanosine excretion and its intense imuuno-reactive staining in the glomeruli were markedly higher in diabetic than in control rats. These were ameliorated by a treatment with a selective PKC-βinhibitor, ruboxistaurin (RBX) mesylate. The expression of p47phox and p67phox, cytosolic subunits of NADPH oxidase, was increased in diabetic glomeruli. NADPH oxidase activity was significantly enhanced in diabetic glomeruli and was also improved by RBX treatment by preventing the membranous translocation of p47phox and p67phox. Adenoviral-mediated PKC-β2 overexpression enhanced ROS generation by stimulating the membranous translocation of p47phox and p67phox in cultured mesangial cells. These results suggest that oxidative stress is enhanced in the diabetic glomeruli of early stage of diabetes, and NADPH oxidase is activated, at least in part through PKC-β-dependent p47phox and p67phox membranous translocation.
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