Mechanism of glomerular abnormality by oxidative stress in diabetic nephropathy

糖尿病肾病氧化应激导致肾小球异常的机制

• 批准号: 13671184
• 负责人: HANEDA Masakazu
• 金额: $ 2.3万
• 依托单位: Shiga University of Medical Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13671184/
• 关键词: 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

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.

氧化应激在糖尿病血管并发症（包括糖尿病肾病）的发生中起重要作用。在这项研究中，我们研究了糖尿病肾小球的氧化应激是否增强，以及蛋白激酶C (PKC)-β激活在调节NADPH氧化酶（活性氧（ROS）的主要来源）中的作用。2、4周龄时链脲佐剂诱导的糖尿病大鼠肾小球中过氧化氢酶、谷胱甘肽过氧化物酶、cuzn超氧化物歧化酶等抗氧化酶mRNA表达均无变化。血红素加氧酶-1 (HO-1) mRNA表达在糖尿病肾小球中升高。胰岛素和维生素E治疗可使糖尿病肾小球中HO-1的表达正常化。免疫组化分析显示HO-1在肾小球系膜细胞和上皮细胞中优先表达增强。糖尿病大鼠尿8-羟基脱氧鸟苷排泄量及其在肾小球内的强烈免疫反应染色明显高于对照组。这些通过选择性PKC-β抑制剂甲磺酸ruboxistaurin （RBX）治疗得到改善。糖尿病肾小球内NADPH氧化酶胞质亚基p47phox和p67phox表达升高。糖尿病肾小球NADPH氧化酶活性显著增强，RBX通过阻止p47phox和p67phox的膜易位也改善了NADPH氧化酶活性。腺病毒介导的PKC-β2过表达通过刺激培养的系膜细胞中p47phox和p67phox的膜性易位而增强ROS的产生。这些结果表明，糖尿病早期肾小球氧化应激增强，NADPH氧化酶被激活，至少部分是通过PKC-β依赖的p47phox和p67phox膜易位。

项目成果

Koya D, Hayashi K, Kitada M, Kashiwagi A, Kikkawa R, Haneda M: "Effect of antioxidants in diabetes-induced oxidative stress in the glomeruli of diabetic rats."J Am Soc Nephrol. 14. S250-S252 (2003)

Koya D、Hayashi K、Kitada M、Kashiwagi A、Kikkawa R、Haneda M：“抗氧化剂对糖尿病大鼠肾小球中糖尿病诱导的氧化应激的影响。”J Am Soc Nephrol。