Thioredoxin-interacting Protein Mediates High Glucose-induced Reactive Oxygen Species Generation by Mitochondria and the NADPH Oxidase, Nox4, in Mesangial Cells
Thioredoxin-interacting Protein Mediates High Glucose-induced Reactive Oxygen Species Generation by Mitochondria and the NADPH Oxidase, Nox4, in Mesangial Cells
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DOI：
10.1074/jbc.m112.419101
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发表时间：
2013-03-08
影响因子：
4.8
通讯作者：
Fantus, I. George
中科院分区：
文献类型：
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作者：
Shah, Anu;Xia, Ling;Fantus, I. George
硫氧还蛋白相互作用蛋白（TxNIP）被高葡萄糖上调，并与氧化应激有关。它与高血糖诱导的β细胞功能障碍和细胞凋亡有关。由于高糖和氧化应激介导糖尿病肾病（DN），研究了TxNIP在肾系膜细胞活性氧（ROS）产生和胶原合成中的作用。为了确定TxNIP的作用，将从野生型C3 H和TxNIP缺陷型Hcb-19小鼠培养的小鼠系膜细胞（MC）在HG中孵育。共聚焦显微镜用于测量总的和线粒体ROS产生（DCF和MitoSOX）和胶原IV。Trx和NADPH氧化酶活性测定和NADPH氧化酶亚型，Nox 2和Nox 4，和抗氧化酶的免疫印迹法测定。C3 H MC暴露于HG引起细胞和线粒体ROS以及Nox 4蛋白表达和NADPH氧化酶激活的显着增加，而Hcb-19 MC显示无反应。HG仅在C_3H MC中减弱Trx活性。Hcb-19 MC的这些缺陷不是由于抗氧化酶的增加或ROS的清除，而是与ROS生成减少有关。腺病毒介导的TxNIP在Hcb-19 MC中的过表达和TxNIP在C3 H中的siRNA敲低证实了TxNIP的特异性作用。HG中的IV型胶原积聚在Hcb-19细胞中显著减少。TxNIP是HG-ROS信号通路的关键组分，是诱导线粒体和总细胞ROS以及NADPH氧化酶亚型Nox 4所必需的。TxNIP是预防DN的潜在靶点。
Thioredoxin-interacting protein (TxNIP) is up-regulated by high glucose and is associated with oxidative stress. It has been implicated in hyperglycemia-induced beta-cell dysfunction and apoptosis. As high glucose and oxidative stress mediate diabetic nephropathy (DN), the contribution of TxNIP was investigated in renal mesangial cell reactive oxygen species (ROS) generation and collagen synthesis. To determine the role of TxNIP, mouse mesangial cells (MC) cultured from wild-type C3H and TxNIP-deficient Hcb-19 mice were incubated in HG. Confocal microscopy was used to measure total and mitochondrial ROS production (DCF and MitoSOX) and collagen IV. Trx and NADPH oxidase activities were assayed and NADPH oxidase isoforms, Nox2 and Nox4, and antioxidant enzymes were determined by immunoblotting. C3H MC exposed to HG elicited a significant increase in cellular and mitochondrial ROS as well as Nox4 protein expression and NADPH oxidase activation, whereas Hcb-19MC showed no response. Trx activity was attenuated by HG only in C3H MC. These defects in Hcb-19 MC were not due to increased antioxidant enzymes or scavenging of ROS, but associated with decreased ROS generation. Adenovirus-mediated overexpression of TxNIP in Hcb-19MC and TxNIP knockdown with siRNA in C3H confirmed the specific role of TxNIP. Collagen IV accumulation in HG was markedly reduced in Hcb-19 cells. TxNIP is a critical component of the HG-ROS signaling pathway, required for the induction of mitochondrial and total cell ROS and the NADPH oxidase isoform, Nox4. TxNIP is a potential target to prevent DN.