Prorenin Receptor Mediates Early Changes in Diabetic Kidney

描述（申请人提供）：（Pro）肾素受体（PRR）是新发现的肾素-血管紧张素系统的组分。PRR确切的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，高血糖增加PRR的表达和活性，这是一个过程，由血管紧张素AT 1受体（AT 1 R），主要是通过他们的异源二聚体调节。由于AT 1 R和PRR之间的相互作用，V-ATP酶和Wnt 3a的表达和活性上调，导致肾脏炎症、纤维化和蛋白尿。体内肾内注射PRR shRNA或Wnt 3a shRNA可减少与高血糖症相关的蛋白尿、肾脏炎症和形态学变化。基于这些数据，PRR可能直接导致高血糖诱导的肾损伤的发生。本研究计划的长期目标是阐明有助于调节PRR表达和功能的体外和体内新机制，并评估该受体与AT 1 R、空泡-ATP酶（V-ATP酶）和Wnt 3a相互作用的病理学意义，并导致高血糖诱导的肾脏疾病的发展。为了实现这一目标，我们将利用基本原理和新的综合方法，包括在清醒的正常血糖和高血糖链脲佐菌素诱导的糖尿病大鼠中利用肾PRR、V-ATP酶或Wnt 3a的联合敲低和肾间质微透析技术的体内研究。这些研究将得到最先进的体外细胞和分子技术的补充，这些技术利用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，该建议的中心假设是，在高血糖的情况下，PRR活性是 通过与AT 1 R的二聚化增加，导致V-ATP酶和Wnt 3a信号传导途径的表达和活性增强，从而诱导肾脏炎症、纤维化和蛋白尿。我们将追求以下具体目标：目的1：为了测试假设，高血糖增加PRR的表达和活性及其与AT 1 R的异源二聚化，导致肾脏炎症，纤维化和蛋白尿。目的2：验证高血糖增强PRR活性通过增加V-ATPase的表达和活性介导肾损伤的假说。目的3：验证高血糖增强的PRR活性通过增加Wnt 3a的表达和活性而导致肾损伤的假设。这些研究有望确定与PRR相关的新的病理生理机制，并可能导致开发新的治疗策略来治疗高血糖诱导的肾脏疾病。

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.