Prorenin Receptor Mediates Early Changes in Diabetic Kidney

描述（由申请人提供）：（Pro）肾素受体（PRR）是肾素-血管紧张素系统中新发现的成分。PRR的确切生理和病理功能尚未确定。我们在体外和体内的初步研究表明，高血糖会增加PRR的表达和活性，这一过程主要通过血管紧张素AT1受体（AT1R）的异源二聚化来调节。由于AT1R和PRR之间的相互作用，V-ATPase和Wnt3a的表达和活性上调，导致肾脏炎症纤维化和蛋白尿。在体内肾间质内给予PRR shRNA或Wnt3a shRNA可减少蛋白尿、肾脏炎症和与高血糖相关的形态学改变。基于这些数据，PRR可能直接促进了高血糖性肾损伤的发展。我们的长期研究目标是阐明体外和体内调控PRR表达和功能的新机制，并评估该受体与AT1R、液泡- atp酶（v - atp酶）和Wnt3a相互作用，导致高血糖性肾脏疾病发展的病理意义。为了实现这一目标，我们将采用一种基本原理和新颖的综合方法，包括在有意识的正常血糖和高血糖链脲霉素诱导的糖尿病大鼠中使用联合下调肾脏PRR、v - atp酶或Wnt3a和肾间质微透析技术的体内研究。这些研究将辅以最先进的体外细胞和分子技术，利用siRNA、shRNA、EMSA、ChIP测定和激光扫描共聚焦FRET显微镜来严格检验所提出的假设。根据我们最近的观察和初步数据，本建议的中心假设是，在高血糖的存在下，PRR活性是

DESCRIPTION (provided by applicant): (Pro)renin receptor (PRR) is a newly discovered component of the renin-angiotensin system. The exact physiologic and pathologic functions of PRR are not established yet. Our preliminary studies in vitro and in vivo demonstrated that hyperglycemia increases PRR expression and activity, a process that is regulated by angiotensin AT1 receptor (AT1R), mainly via their heterodimerization. As a result of the interaction between AT1R and PRR there is upregulation of V-ATPase and Wnt3a expression and activity leading to renal inflammation fibrosis and albuminuria. In vivo intrarenal interstitia administration of PRR shRNA or Wnt3a shRNA reduced albuminuria, renal inflammation and morphologic changes associated with hyperglycemia. Based on these data, it is likely that PRR directly contributes to development of hyperglycemia-induced renal injury. The long-term goal of our research program is to elucidate the in vitro and in vivo novel mechanisms contributing to the regulation of PRR expression and function and evaluate the pathological significance of this receptor interaction with AT1R, vacuolar-ATPase (V-ATPase) and Wnt3a, and lead to development of hyperglycemia- induced renal disease. To achieve this goal, we will utilize a rationale and novel integrated approaches, consisting of in vivo studies utilizing combined knockdown of renal PRR, V-ATPase or Wnt3a and renal interstitial microdialysis technique in conscious normoglycemic and hyperglycemic streptozotocin- induced diabetes rats. These studies will be complemented by state-of-the-art in vitro cellular and molecular techniques utilizing siRNA, shRNA, EMSA, ChIP assays, and Laser Scanning Confocal FRET microscopy to rigorously test the proposed hypothesis. Based on our recent observations and preliminary data, the central hypothesis of this proposal is that in presence of hyperglycemia, PRR activity is increased by dimerization with AT1R leading to enhanced expression and activity of V-ATPase and Wnt3a signaling pathways to induce renal inflammation, fibrosis and albuminuria. We will pursue the following specific aims: Aim 1: To test the hypothesis that hyperglycemia increases PRR expression and activity and its heterodimerization with AT1R, leading to renal inflammation, fibrosis and albuminuria. Aim 2: To test the hypothesis that hyperglycemia- enhanced PRR activity mediates renal injury by increasing the expression and activity of V-ATPase. Aim 3: To test the hypothesis that hyperglycemia-enhanced PRR activity contributes to renal injury via increased expression and activity of Wnt3a. These studies are expected to identify novel pathophysiologic mechanisms related to PRR and could lead to development of new therapeutic strategies for treating hyperglycemia-induced renal disease.