Role of Rho Kinases in Diabetic Nephropathy

描述（由申请人提供）：Rho激酶（ROCK）是一种丝氨酸/苏氨酸蛋白激酶，其作为小G蛋白RhoA的下游效应器之一。 RhoA/ROCK 通路在介导各种细胞过程中发挥重要作用，包括细胞骨架重塑、细胞增殖和基因表达。最近，RhoA/ROCK 通路已成为治疗冠状血管痉挛、中风、勃起功能障碍和高血压的有希望的靶点。在本提案中，我们认为 ROCK 通过参与调节活性氧 (ROS) 信号通路，在糖尿病肾病 (DN) 的发病机制中也发挥着关键作用。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转导 (Danesh FR et al. Proc. Natl. Acad. Sci. 2002)，2) ROCK 阻断可改善 2 型糖尿病 db/db 模型中 DN 的进展 (Kolavennu V et al. Diabetes 2007)，以及 3) 我们的初步数据表明 ROCK 激活起着关键作用在线粒体和 NADPH 氧化还原信号传导中发挥作用。基于这些初步观察，我们现在提出了一种集成的体外和体内方法来测试三个特定目标。目标 1：检验以下假设：在细胞水平上，ROCK 介导糖尿病环境中线粒体和 NADPH 衍生的 ROS 过量产生之间的串扰。目标 2：检验以下假设：在 1 型和 2 型糖尿病实验模型中选择性抑制 ROCK 可通过抑制 ROCK 介导的 ROS 产生来改善 DN 的进展。目标 3：测试 ROCK 的组织特异性条件基因靶向在 DN 中的效果。该申请的结果将在三个方面提供重大进展：首先，该提案的成功完成不仅与肾脏研究相关，而且还将为理解氧化还原信号传导的空间和时间行为提供一个框架。其次，它将评估 RhoA/ROCK 信号在肾脏中的作用。第三，它将导致 DN 新型治疗策略的发展。 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。当前的研究将重点关注可能与糖尿病肾病进展有关的新途径。我们认为，抑制 RhoA/ROCK 通路有望成为改善糖尿病微血管结局的新型治疗策略。

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.