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Kidney disease mechanisms associated with human genetic variation

与人类遗传变异相关的肾脏疾病机制

基本信息

批准号：
8642932
负责人：
Leslie A Bruggeman
金额：
$ 54.27万
依托单位：
CASE WESTERN RESERVE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-07-20 至 2018-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8642932
关键词：
AIDS-Associated Nephropathy Accounting Address African African American American Animals Apolipoproteins Autophagocytosis Autophagosome Binding Biological Biology Biopsy Specimen Blood Cardiovascular Diseases Cell Culture Techniques Cell Line Cells Cessation of life Chromosomes, Human, Pair 22 Chronic Kidney Failure Code Complementary DNA Complex Data Development Diagnosis Disease Docking Electron Microscopy End stage renal failure Environmental Risk Factor Expenditure Experimental Designs Gene Expression Profile Genes Genetic Epistasis Genetic Predisposition to Disease Genetic Variation Genotype Goals HIV HIV Infections HIV-1 Haplotypes Healthcare Home environment Homeostasis Human Human Genetics Immunofluorescence Immunologic In Situ In Situ Hybridization In Vitro Infection Infection prevention Injury Kidney Kidney Diseases Kidney Failure Knowledge Location Lysosomes Maps Mediating Medicare Metabolic Methods Modeling Mus NPHS2 protein Normal tissue morphology Pathogenesis Pathology Pathway interactions Patients Pattern Phenotype Population Prevention therapy Protein Biosynthesis Proteins Publishing Regulation Resistance Risk SNAP receptor Severities Signal Transduction Stress Testing Time Tissues Transgenic Mice Trypanosoma United States Variant Viral Viral Proteins Virus base diabetic disease diagnosis disease phenotype genetic association health disparity high risk improved in vivo in vivo Model mouse model nef Protein nephrin non-diabetic novel overexpression particle pathogen podocyte promoter public health relevance research study response risk variant transgene expression uptake vector

项目摘要

Chronic kidney disease (CKD), like many complex disease phenotypes, reflects dependent interactions between genetic susceptibilities and environmental factors. APOL1 variants explain much of the excess risk of advanced non-diabetic CKD in patients of African ancestry. However, only some patients with risk genotypes develop kidney disease, suggesting that genetic epistasis or environmental stress is required to trigger variant APOL1-dependent kidney injury. To investigate how APOL1 variants result in CKD, we have focused on HIV- associated nephropathy (HIVAN), the disease most robustly associated with APOL1 risk haplotypes and clearly dependent on an environmental factor, HIV-1 infection. Our preliminary data demonstrate APOL1 is expressed in the podocyte, and APOL1 overexpression activates autophagy. Although mTor-dependent suppression of core autophagy may cause diabetic glomerulopathy, a renal pathology not associated with APOL1 variants, we provide evidence that the genetic association of APOL1 with CKD results from APOL1- dependent regulation of distinct, selective autophagy pathways, which result in the destruction of pathogens. We hypothesize that APOL1 is an autophagic adaptor that tethers a docking SNARE (VAMP8) displayed on lysosomes to the autophagosomal protein LC3-II. The tethering function of APOL1 is activated by binding a triggering molecule, the HIV protein Nef, and results in the selective degradation of autophagosomes carrying HIV viral particles and proteins. Variant APOL1 proteins are functionally defective, permitting HIV to persist in the infected cell and continue synthesis of viral proteins including Nef. Nef blocks autophagic elimination of the virus and is critical for development of HIVAN. Our proposed experiments address three unanswered and novel questions regarding APOL1 function in CKD. Is APOL1 synthesized in situ in kidney and what is its subcellular home? Does circulating or renal-expressed variant APOL1 mediate kidney disease? Does dysregulation of autophagy pathways activated in response to specific environmental stresses result in kidney disease in patients with APOL1 risk genotypes? These questions are addressed with the following Specific Aims: 1. Determine APOL1 expression and intracellular location in normal kidney, and determine if APOL1 localization varies with risk genotype and/or disease diagnosis; 2. Generate in vivo models for the study of APOL1 function; 3. Characterize protein interactions between APOL1 with VAMP8 and the HIV protein Nef and examine normal and variant APOL1 regulation of autophagy in cell lines and cultured podocytes. These studies can result in novel, mechanism-based therapies, improve health disparities in African American patients and identify novel mechanisms of human CKD.

慢性肾脏病（CKD），像许多复杂的疾病表型，反映了依赖性相互作用遗传易感性和环境因素之间的联系APOL 1变异解释了大部分的过度风险，非洲血统的晚期非糖尿病CKD患者。然而，只有一些具有风险基因型的患者，发生肾脏疾病，这表明需要遗传上位性或环境压力来触发变异 APOL 1依赖性肾损伤为了研究APOL 1变异如何导致CKD，我们专注于HIV-1。相关性肾病（HIVAN），与APOL 1风险单倍型最密切相关的疾病，很明显依赖于环境因素HIV-1感染我们的初步数据表明APOL 1是在足细胞中表达，并且APOL 1过表达激活自噬。虽然mTOR依赖核心自噬的抑制可能导致糖尿病性肾小球病，这是一种与糖尿病性肾小球病无关的肾脏病理学。 APOL 1变异，我们提供的证据表明，APOL 1与CKD的遗传关联是由APOL 1- 不同的，选择性的自噬途径的依赖性调节，导致病原体的破坏。我们假设APOL 1是一种自噬适配器，它连接着一个显示在细胞表面的对接陷阱（VAMP 8）。自噬体蛋白LC 3-II。APOL 1的拴系功能是通过结合一种触发分子，HIV蛋白Nef，并导致携带自噬体的选择性降解。 HIV病毒颗粒和蛋白质。APOL 1蛋白的变异体在功能上有缺陷，使得HIV在体内持续存在。感染细胞并继续合成病毒蛋白，包括Nef。Nef阻断自噬消除病毒，对于艾滋病毒的发展至关重要。我们提出的实验解决了三个悬而未决的问题，关于CKD中APOL 1功能的新问题。APOL 1是在肾脏原位合成的吗？亚细胞家循环或肾脏表达的APOL 1变体是否介导肾脏疾病？并自噬通路的失调响应于特定的环境应激而被激活，导致肾脏携带APOL 1风险基因型的患者的疾病？这些问题通过以下具体的目的：1.确定正常肾脏中APOL 1的表达和细胞内定位，并确定APOL 1 定位随风险基因型和/或疾病诊断而变化; 2.生成用于研究的体内模型 APOL 1功能; 3.表征APOL 1与VAMP 8和HIV蛋白Nef之间的蛋白质相互作用，检查细胞系和培养的足细胞中正常和变异的APOL 1对自噬的调节。这些研究可以产生新的，基于机制的疗法，改善非裔美国人的健康差距，患者和识别人类CKD的新机制。