Proteomic approach to protein involving diabetic nephropathy

在糖尿病肾病或非糖尿病肾病中，TGF-β在疾病进展中起作用。鉴定与TGF-β或其下游分子如Smad相互作用的蛋白质是研究与进行性糖尿病或非糖尿病肾病相关的新蛋白质的策略。肾素-血管紧张素系统（RAS）和晚期糖基化终产物（AGEs）的积累参与了糖尿病肾病的发病机制。我们研究了AGEs是否可以激活自分泌血管紧张素II（Ang II）信号并随后诱导培养的大鼠系膜细胞中转化生长因子-β（TGF-β）-Smad信号。AGEs增加系膜细胞内ROS的产生，这种作用被抗AGEs的抗血清显著抑制。AGEs也被发现以时间和剂量依赖性的方式刺激Ang II的产生，这完全被抗氧化剂N-乙酰半胱氨酸（NAC）所阻止。AGE诱导的TGF-β过度产生被坎地沙坦阻断，坎地沙坦是一种血管紧张素II 1型受体（AT 1 R）拮抗剂。坎地沙坦和抗TGF-β中和抗体均阻止AGEs诱导的Smad 2磷酸化和TGF-β诱导的启动子活性。AGEs被发现抑制DNA合成和刺激从头蛋白质合成和纤连蛋白的生产与p27的上调。坎地沙坦或抗TGF-β的多克隆抗体可预防所有这些现象。AGE-beta介导的ROS生成激活TGF-β-Smad信号传导，随后通过自分泌产生Ang II诱导系膜细胞肥大和纤连蛋白合成。因此，AGE、Ang II和TGF-β-Smad在糖尿病肾病中密切相互作用。在此基础上，我们将进一步研究糖尿病肾病相关蛋白。

In diabetic renal disease or non-diabetic renal disease, TGF-beat plays a role in the disease progression. Identification of the protein interacting TGF-beta or its down-stream molecule such as Smad is the strategy to investigate the novel protein involving the progressive diabetic or non-diabetic nephropathy. The renin-angiotensin system(RAS)and the accumulation of advanced glycation end products(AGEs)have been implicated in the pathogenesis of diabetic nephropathy. we investigated whether AGEs could activate autocrine angiotensin II(Ang II)signaling and subsequently induce transforming growth factor-beta(TGF-beta)-Smad signaling in cultured rat mesangial cells. AGEs increased intracellular ROS generation in mesangial cells, and this effect was significantly inhibited by an antiserum against RAGE. AGEs also were found to stimulate Ang II production in a time- and dose-dependent manner, which was completely prevented by an antioxidant, N-acetylcysteine(NAC). AGE-induced TGF-beta overproduction was blocked by candesartan, an Ang II type 1 receptor(AT1R)antagonist. Both candesartan and neutralizing antibody against TGF-beta prevented AGEs-induced Smad2 phosphorylation and TGF-beta-inducible promoter activity. AGEs were found to inhibit DNA synthesis and to stimulate de novo protein synthesis and fibronectin production in association with up-regulation of p27. All of these phenomena were prevented by candesartan or a polyclonal antibody against TGF-beta. AGE-RAGE-mediated ROS generation activates TGF-beta-Smad signaling and subsequently induces mesangial cell hypertrophy and fibronectin synthesis by autocrine production of Ang II. Thus, the AGE, Ang II, and TGF-b-Smad interact tightly in diabetic nephropathy. Base upon these result, we are going to investigate the protein involving diabetic nephropathy.