Endocytic Pathway Dysfunction in Dent Disease

摘要 肾内细胞对过滤蛋白摄取受损所致的小管性蛋白尿 近端肾小管(PT)是早期肾功能障碍的常见特征，具有显著的危险性 用于终末期肾脏疾病的发展。这项提议的目的是理解 Dent病的基础，一种进行性遗传性疾病，以肾小管蛋白尿为特征 由2Cl-/H+交换器ClC-5突变引起。增强了巨蛋白的降解，a 与过滤蛋白结合的多配体共受体被认为是肾小管性蛋白尿的基础。 然而，鼠疫，受影响的贩运步骤是未知的，pH值的贡献是未知的 对氯离子动态平衡对该病表型的影响存在争议。我们将利用基因的组合， 实现以下目标的形态、数学建模和生物化学方法 目的：(1)在ClC-5基因敲除的PT细胞中确定膜运输受损的步骤(S)；(2) 确定ClC-5的缺失与巨蛋白表达减少有关的分子机制；以及(3) 确定恢复Dent小鼠模型中megalin表达和功能的治疗靶点 疾病。

Abstract Tubular proteinuria resulting from impaired endocytic uptake of filtered proteins by the kidney proximal tubule (PT) is a common feature of early kidney dysfunction that poses a significant risk for development of end-stage renal disease. This proposal aims to understand the mechanistic basis of Dent disease, a progressive genetic disorder characterized by tubular proteinuria that is caused by mutations in the 2Cl-/H+ exchanger ClC-5. Enhanced degradation of megalin, a multiligand co-receptor that binds to filtered proteins, is thought to underlie the tubular proteinuria in Dent disease, however, the step in trafficking that is affected is unknown, and the contribution of pH vs. Cl- homeostasis to the disease phenotype is disputed. We will utilize a combination of genetic, morphological, mathematical modeling, and biochemical approaches to accomplish the following aims: (1) identify the step(s) in membrane traffic that are impaired in ClC-5 knockdown PT cells; (2) determine the molecular mechanism that links loss of ClC-5 to reduced megalin expression; and (3) identify therapeutic targets for restoring megalin expression and function in a mouse model of Dent disease.