Role of Rho Kinases in Diabetic Nephropathy

描述(申请人提供)：Rho激酶(ROCK)是一种丝氨酸/苏氨酸蛋白激酶，其功能是小G蛋白RhoA的下游效应器之一。RhoA/ROCK通路在细胞骨架重塑、细胞增殖和基因表达等多种细胞过程中发挥重要作用。最近，RhoA/ROCK通路已成为治疗冠状动脉血管痉挛、中风、勃起功能障碍和高血压的有希望的靶点。在这项研究中，我们认为ROCK还通过参与调节活性氧(ROS)信号通路在糖尿病肾病(DN)的发病机制中发挥关键作用。我们的假设基于几个新的观察结果：1)RhoA/ROCK通路参与葡萄糖诱导的信号传递(Danesh FR等人)。程序娜塔莉。阿卡德。SCI。2002)，2)阻断ROCK改善2型糖尿病db/db模型中糖尿病肾病的进展(Kolvennu V等人)。3)我们的初步数据表明ROCK激活在线粒体和NADPH氧化还原信号中都起着关键作用。基于这些初步观察，我们现在提出一种综合的体外和体内方法来测试三个特定的目标。目的1：验证在细胞水平上，ROCK在糖尿病环境中介导线粒体和NADPH来源的ROS过度产生之间的串扰的假说。目的：验证在1型和2型糖尿病模型中选择性抑制ROCK通过抑制ROCK介导的ROS产生而改善糖尿病肾病进展的假说。目的：检测ROCK的组织特异性条件基因打靶在糖尿病肾病中的作用。这一应用的发现将在三个方面提供重大进展：第一，这一提议的成功完成不仅与肾脏研究有关，还将为理解氧化还原信号的时空行为提供一个框架。其次，它将评估RhoA/ROCK信号在肾脏中的作用。第三，它将导致糖尿病肾病新的治疗策略的发展。 公共卫生相关性： 糖尿病肾病仍然是美国肾衰竭的主要原因。目前的研究将集中在一种可能与糖尿病肾病进展有关的新途径上。我们认为，抑制RhoA/ROCK通路有望成为改善糖尿病微血管预后的一种新的治疗策略。

DESCRIPTION (provided by applicant): Rho kinase (ROCK) is a serine/threonine protein kinase which functions as one of the downstream effectors for the small G-protein RhoA. The RhoA/ROCK pathway has an important role in mediating various cellular processes, including cytoskeletal remodeling, cell proliferation, and gene expression. More recently, the RhoA/ROCK pathway has emerged as a promising target in the treatment of coronary vasospasm, stroke, erectile dysfunction, and hypertension. In this proposal, we argue that ROCK also plays a critical role in the pathogenesis of diabetic nephropathy (DN) via its involvement in modulating the reactive oxygen species (ROS) signaling pathway. Our hypothesis is based on several novel observations: 1) RhoA/ROCK pathway is involved in glucose-induced signaling (Danesh FR et al. Proc. Natl. Acad. Sci. 2002), 2) Blockade of ROCK ameliorates progression of DN in the db/db model of type 2 diabetes (Kolavennu V et al. Diabetes 2007), and 3) our preliminary data suggesting that ROCK activation plays a pivotal role in both mitochondrial and NADPH redox signaling. Based upon these initial observations, we now propose an integrated in vitro and in vivo approach to test three specific aims. Aim 1: To test the hypothesis that at the cellular level, ROCK mediates the cross-talk between mitochondrial- and NADPH-derived ROS overproduction in the diabetic milieu. Aim 2: To test the hypothesis that selective inhibition of ROCK in the experimental models of type 1 and type 2 diabetes ameliorates the progression of DN by inhibiting ROCK-mediated ROS production. Aim 3: To test the effect of tissue-specific conditional gene targeting of ROCK in DN. The findings of this application will provide a significant advance in three aspects: first, the successful completion of this proposal is not only relevant to kidney research, but it will also provide a framework for understanding the spatial and temporal behavior of redox signaling. Second, it will assess the role of RhoA/ROCK signaling in the kidney. And third, it will lead to development of novel therapeutic strategies in DN. PUBLIC HEALTH RELEVANCE: Diabetic nephropathy remains the leading cause of renal failure in the U.S. The current study will focus on a novel pathway possibly involved in the progression of diabetic kidney disease. We propose that inhibition of the RhoA/ROCK pathway holds promise as a novel therapeutic strategy to improve microvascular outcomes in diabetes.