PODOCYTE ENDOPLASMIC RETICULUM STRESS AND NEPHROTIC SYNDROME

摘要 肾病综合征(NS)的特征是大量蛋白尿和肾功能丧失的风险增加。 功能。本病发病率高，死亡率高，占终末期肾脏疾病的15%。 疾病，在美国每年的成本超过30亿美元。大多数病例都没有有效的治疗方法。 由基因突变引起的NS。我们的研究一直集中在一种单基因形式的NS上，这种形式由一种 LAMB2错义突变(C321R)是NS中最常见的突变基因之一。层粘连蛋白2编码 LAMB2是肾小球基底层粘连蛋白-521(521)的一个组成部分，是肾小球基底层粘连蛋白的主要三聚体 膜(GBM)。使用我们建立的基因敲除/转基因小鼠模型，我们发现足细胞 内质网应激与错折叠的C321R-LAMB2分泌缺陷 足细胞进入基底膜导致蛋白尿。此外，我们最近发现了一种内质网可溶性因子， 促进内质网应激足细胞的存活。 这项提案的总体目标是描绘调节重要死亡和 C321R-LAMB2突变诱导的足细胞内质网应激激活的生存通路，以确定 足细胞内质网应激在携带有害错义突变的NS患者中的作用 研究遗传型NS的新治疗策略。为了实现我们的研究目标，我们将利用 小鼠遗传模型和Access两大人类NS队列，肾病综合征研究网络 (海王星)和华盛顿大学肾脏翻译研究核心(Wu KTRC)。我们有 组建了一个跨学科团队，其中包括多名合作调查员和合作者，他们需要 具有开创性的内质网应激研究、人类和小鼠遗传学、下一代测序和高级 吞吐量筛选。 拟议的研究将帮助我们根据潜在的分子机制对NS患者进行分类，分层 疾病风险，并为足细胞内质网功能障碍引起的NS患者发现高度针对性的治疗方法。

Abstract Nephrotic syndrome (NS) is characterized by heavy proteinuria and increased risk of loss of kidney function. It causes serious morbidity and high mortality, accounting for 15% of prevalent end-stage renal disease at an annual cost of more than $3 billion in the US. There is no effective treatment for most cases of NS caused by genetic mutations. Our research has been focused on a monogenic form of NS caused by a missense mutation (C321R) of LAMB2, one of the most commonly mutated genes in NS. Laminin 2 encoded by LAMB2 is a component of laminin-521 ( 5 2 1), the major laminin trimer of the glomerular basement membrane (GBM). Using our established knockout/transgenic mouse model, we have found that podocyte endoplasmic reticulum (ER) stress and subsequent defective secretion of misfolded C321R-LAMB2 from podocytes to the GBM lead to proteinuria. Furthermore, we have recently discovered an ER soluble factor that promotes the survival of ER-stressed podocytes. The overall goals of this proposal are to delineate molecular mechanisms regulating important death and survival pathways activated by the C321R-LAMB2 mutation-induced podocyte ER stress, to determine the contribution of podocyte ER stress in NS patients carrying putative deleterious missense variants, and to investigate novel treatment strategies for genetic forms of NS. To accomplish our research goals, we will utilize mouse genetic models and access two major human NS cohorts, Nephrotic Syndrome Study Network (NEPTUNE) and the Washington University Kidney Translational Research Core (WU KTRC). We have assembled an interdisciplinary team including multiple co-investigators and collaborators with the required expertise in pioneering ER stress research, human and mouse genetics, next generation sequencing, and high throughput screening. The proposed study will help us classify NS patients based on underlying molecular mechanisms, stratify disease risk, and discover highly-targeted treatments for NS patients caused by podocyte ER dysfunction.