Genetic Determinants of Susceptibility to Kidney Disease in African Americans

描述(申请人提供)：非洲裔美国人罹患终末期肾病(ESRD)的风险是欧洲裔美国人的3倍以上。这种不成比例的风险在几乎所有形式的肾脏疾病中都很明显，但只有一小部分可以用社会经济地位和/或获得医疗保健的机会较差来解释。最近的研究发现了编码Myh9的基因的多态性，Myh9是一种非肌肉肌球蛋白重链，与非裔美国人患ESRD的易感性有关，这解释了归因风险的重要组成部分。确定Myh9变异与终末期肾病风险之间的这种关联是一项重大突破。然而，由于这些变异不包括外显子或内含子：外显子连接序列的显著变化，主要的研究机会和科学知识缺口是确定Myh9基因多态与肾脏损伤发病机制之间的联系。由于Myh9是一种结构性的细胞内蛋白，它在肾脏疾病病理生物学中的作用很难通过临床样本的分析来研究。尽管如此，要将这种基因关联的发现转化为对高危个体的改进预防和治疗，将需要准确了解这些基因变异影响肾脏疾病进程的机制。因此，我们建议在没有小鼠同源基因的情况下，将人类Myh9单倍型插入到小鼠基因组的同线位置的小鼠系中。这些线条将使用一种新颖而强大的两步法产生，其中在胚胎干细胞(ES)中以允许将类似的人类基因直接快速引入缺失的基因的方式切除小鼠基因。我们开发这种方法的经验表明，插入的人类基因在小鼠体内保留了其关键的功能和调节特性。因此，这些动物模型的建立将为在体内研究人类MHY9单倍型在精确控制的遗传和环境条件下的生理后果提供独特的机会，以了解它们在肾脏损伤发展中的作用。我们已经组建了一支高度成功的多学科团队，以确保这些老鼠品系的产生和初步鉴定能够在《复苏法案》规定的两年内完成。这些动物模型将成为确定预防非裔美国人ESRD的新策略的有力工具。 公共卫生相关性：非洲裔美国人患终末期肾病(ESRD)的风险明显高于欧洲裔美国人。虽然这种差距已经被认识到一段时间了，但其原因尚不清楚。最近，两个小组独立确定了非裔美国人患ESRD的风险与一种名为Myh9的基因变异之间的联系。然而，目前还不清楚这种基因变异是如何导致肾脏疾病的。在我们提出的研究中，我们计划培育出将人类Myh9变体插入到小鼠基因组中的小鼠，在那里它们可以在精确控制的遗传和环境条件下进行研究，以了解它们在肾脏损伤发展中的作用。这些动物模型将成为确定预防非裔美国人ESRD的新策略的有力工具。

DESCRIPTION (provided by applicant): The risk for developing end-stage renal disease (ESRD) in African Americans is more than 3-fold higher than European Americans. This disproportionate risk is apparent for virtually all forms of kidney disease, but only a minor portion can be explained by socio-economic status and/or poor access to health care. Recent studies have identified polymorphisms in the gene encoding MYH9, a non-muscle myosin heavy chain that are associated with susceptibility to ESRD in African-Americans, explaining a substantial component of the attributable risk. Identification of this association between MYH9 variants and risk for ESRD is a major breakthrough. However, since these variants do not include significant changes in the sequence of exons or intron:exon junctions, the major research opportunity and scientific knowledge gap is to determine the causal mechanisms connecting MYH9 polymorphisms with the pathogenesis of kidney injury. Because MYH9 is a structural, intra-cellular protein, its role in the pathobiology of kidney disease will be difficult to study in patients through analysis of clinical samples. Nonetheless, translating the discovery of this genetic association into improved prevention and treatment for individuals at risk will require precise understanding of the mechanisms whereby these genetic variants influence the course of kidney disease. Accordingly, we propose to generate mouse lines in which human MYH9 haplotypes are inserted into the syntenic location of the mouse genome in the absence of the mouse orthologue. These lines will be generated using a novel and robust 2-step method wherein the mouse locus is excised in embryonic stem (ES) cells in a manner that allows rapid introduction of the analogous human gene directly into the deleted locus. Our experience in developing this method indicates that the inserted human gene retains its key functional and regulatory properties in the mouse. Thus, development of these animal models will provide a unique opportunity for studying the physiological consequences of human MHY9 haplotypes in vivo under precisely controlled genetic and environmental conditions in order to understand their contributions to the development of kidney injury. We have assembled a highly accomplished, multi-disciplinary team to ensure that the generation and initial characterization of these mouse lines can be completed within the two-year period specified by the Recovery Act. These animal models will be powerful tools for identifying new strategies for preventing ESRD in African Americans. PUBLIC HEALTH RELEVANCE: African Americans have a significantly greater risk of developing end-stage renal disease (ESRD) than European Americans. While this disparity has been recognized for some time, its cause was not known. Recently, two groups independently identified associations between risk for ESRD in African-Americans and variations in a gene called MYH9. However, it is not clear how the variation in this gene could lead to kidney disease. In the studies we are proposing, we plan to generate mice in which the human MYH9 variants are inserted into the mouse genome where they can be studied under precisely controlled genetic and environmental conditions in order to understand their contributions to the development of kidney injury. These animal models will be powerful tools for identifying new strategies for preventing ESRD in African Americans.