Evaluation of Human Variants in Disease Models for End Stage Renal Disease

描述（由申请人提供）：在过去的资助周期中，使用多种大鼠模型，我们已经证明Rab 38负责名为Rf-2的数量性状位点（QTL），鉴定并验证了Sorcs 1负责名为Rf-1的QTL，并鉴定了Shroom 3引起肾小球通透性的变化。我们在克隆另外两个QTL Rf-3和Rf-4的位置方面取得了相当大的进展。与慢性肾脏病遗传学（CKDGen）联盟合作，我们发现SORCS 1和SHROOM 3与人类肾脏疾病显著相关，表明这项工作具有临床意义。 我们的长期目标是确定终末期肾病（ESRD）的遗传结构。我们的数据表明，肾小球通透性和近端小管中蛋白质运输的缺陷是蛋白尿所必需的，这是我们现在的中心假设。提出的具体目的是：1）检测一系列预测为功能障碍的SHROOM 3人类序列变体; 2）鉴定QTL Rf-3潜在的基因/基因组元件（间隔大小1.81 Mb）和QTL Rf-4（间隔大小0.9 Mb）参与肾小球通透性，这被认为是启动蛋白尿;和3）检验中心假设，即肾小球通透性和近端小管中蛋白质运输的功能障碍共同参与蛋白尿的发展。测试这个中心 假设需要使用整个动物，不能在人类身上进行。我们针对该提案的遗传/基因组基础设施包括：亲本菌株的完整基因组序列、包括生物信息学分析在内的NextGen测序工具、“窄”同类菌株、三个已确定的致病基因以及详细的生理特征描述，为发现重要的致病基因创建理想的平台新基因并测试这一新的中心假设。我们将在HEK 293细胞、斑马鱼和人源化致敏FHH大鼠模型中研究SHROOM 3的人类变体。具体来说，Aim 1测试了一系列肾脏疾病的人类变异，并展示了模型系统如何用于跟踪许多全基因组关联研究（GWAS）提名的基因。我们与CKDGen的合作使我们能够测试识别的Rf-3和Rf-4基因是否有助于人类疾病;从而提供有关人类疾病过程的知识。这项研究的基本原理是测试SHROOM 3的人类变异，识别新基因，以及一个新的假设，这将为这种疾病的过程提供新的见解，并可以为未来治疗发病率上升和有效治疗有限的肾脏疾病确定新的靶点。具体目标1-3预计将揭示突变的SHROOM 3如何发挥作用的知识，并确定两个新基因，这两个基因将与已知的途径联系起来，或揭示新的途径。我们还将确定是否涉及两个命中（一个在肾小球，一个在近端小管）。该提案的每个目标都将为定义蛋白尿的遗传结构提供根本性的进展，蛋白尿通常是ESRD的前兆。

DESCRIPTION (provided by applicant): During the past grant cycle, using a variety of rat models, we have proven that Rab38 is responsible for the quantitative trait locus (QTL) named Rf-2, identified and validated that Sorcs1 is responsible for the QTL named Rf-1, and have identified that Shroom3 causes changes in glomerular permeability. We have made considerable strides towards cloning by position two other QTL, Rf-3 and Rf-4. In collaboration with the Chronic Kidney Disease Genetics (CKDGen) Consortium, we found that SORCS1 and SHROOM3 are significantly associated with renal disease in humans, demonstrating that this work has clinical relevance. Our long-term goal is to define the genetic architecture of end stage renal disease (ESRD). Our data suggests that a defect in both the glomerular permeability and protein trafficking in the proximal tubules is required for proteinuria, which is now our centrl hypothesis. The proposed Specific Aims are to 1) test a collection of human sequence variants of SHROOM3 predicted to be dysfunctional; 2) identify the genes/genomic elements underlying the QTL Rf-3 (interval size 1.81 Mb) and QTL Rf-4 (interval size 0.9 Mb) participating in glomerular permeability, which is thought to initiate proteinuria; and 3) test the central hypothesis that dysfunction in both glomerular permeability and protein trafficking in the proximal tubules are participating together in the development of proteinuria. Testing this central hypothesis requires the use of whole animals and cannot be done in human. Our genetic/genomic infrastructure for this proposal includes: complete genomic sequence of parental strains, NextGen sequencing tools including bioinformatic analysis, "narrow" congenic strains, three identified causative genes, as well as detailed physiological characterization creating an ideal platform for discovering important new genes and testing this new central hypothesis. We will study human variants of SHROOM3 in HEK293 cells, zebrafish and humanized sensitized FHH rat model for CKD. Specifically, Aim 1 tests a collection of human variants for renal disease and demonstrates how model systems can be used to follow-up genes nominated by many genome-wide association studies (GWAS). Our collaboration with the CKDGen enables us to test if the genes identified for Rf-3 and Rf-4 contribute to human disease; thereby, providing knowledge about the disease process in humans. The rationale for the proposed research is the test of human variation in SHROOM3, identification of new genes, and a new hypothesis which will provide new insights into this disease process and could identify new targets for future treatment of renal disease with a rising incidence and limited effective treatments. Specific aims 1-3 are expected to reveal the knowledge about how mutated SHROOM3 functions and identify two new genes, which will either link to known pathways or unmask new ones. We will also determine if two hits (one in the glomeruli and one in proximal tubules) are involved. Each aim of this proposal will provide fundamental advances toward defining the genetic architecture of proteinuria which is often the precursor of ESRD.