Molecular Mechanism of APOL1 Associated Kidney Disease

APOL1相关肾脏疾病的分子机制

• 批准号: 8695481
• 负责人: SETH Leo ALPER
• 金额: $ 43.5万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-03 至 2018-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8695481
• 关键词: AIDS-Associated Nephropathy; Accounting; Africa; African; African American; African Trypanosomiasis; Alleles; American; Amino Acid Sequence; Anabolism; Apolipoproteins; Apoptosis; Apoptotic; BH3 Domain; Biological; Biology; Caring; Cell membrane; Cell physiology; Cells; Cellular biology; Code; Disease; Embryo; End stage renal failure; Endocytosis; Epidemic; European; Family member; Focal Segmental Glomerulosclerosis; Frequencies; Functional disorder; Genes; Genotype; Goals; Human; Hypertension; Individual; Injury; Ion Channel; Ions; Kidney; Kidney Diseases; Kidney Failure; Lead; Mediating; Modeling; Molecular; Oocytes; Organelles; Organism; Pathologic; Pathology; Pathway interactions; Peptide Sequence Determination; Permeability; Phenotype; Physiological; Primates; Property; Public Health; Recombinants; Reporting; Resistance; Risk; Role; Structure; System; Testing; Tissues; Trypanosoma; Variant; Whole Organism; Zebrafish; base; design and construction; disorder risk; genetic variant; health disparity; high risk; improved; in vivo; minority health; podocyte; prevent; promoter; public health relevance; research study; risk variant; trafficking

DESCRIPTION (provided by applicant): More than 500,000 Americans suffer from end-stage renal disease (ESRD). African Americans develop ESRD at rates 4-5 fold higher than European Americans. Recently we showed that coding sequence variants in the ApolipoproteinL1 (ApoL1) gene, present only in individuals with recent African ancestry, explain a very large proportion of this health disparity. This has now been confirmed by multiple additional studies. ApoL1 variants have a major impact on different types of kidney disease including hypertension-associated ESRD, focal segmental glomerulosclerosis, and HIV-associated nephropathy. Individuals with two variant ApoL1 alleles have a 7-30 fold increased risk for kidney disease. 3.5 million African Americans likely have the high risk ApoL1 genotype. African Americans without two variant alleles have minimal excess risk. At present, little is known about the biology of ApoL1 or its rol in the kidney. ApoL1 has a defined role in resistance to trypanosomes, and the G1 and G2 variants appear to have become common in Africa because they confer protection against the forms of trypanosomes that cause African Sleeping Sickness. Here, our goal is to elucidate the function of ApoL1 and its role in causing human kidney disease in order to understand the biological mechanisms underlying this large disparity in kidney disease risk. ApoL1 is a Bcl2 family member with a BH3-only domain, suggesting a possible role in apoptosis. Our initial experiments in oocytes lead us to believe that this pathway may be an important mechanism of glomerular injury in ApoL1-associated disease. We propose to: 1. Define the cell biology and cell physiology of ApoL1: We will define the basic cellular biology of ApoL1 including biosynthesis, trafficking, ion channel properties, endocytosis, and effects on organellar structure and function. We will compare wild type and renal risk variant ApoL1 biology to understand the mechanisms that lead to kidney disease. 2. Examine specific effects of ApoL1 on apoptosis in podocytes: We hypothesize that ApoL1 risk variants promote podocyte apoptosis via a BH3 domain in the N- terminus and that the renal risk variants enhance ApoL1's pro-apoptotic effects. We will test this hypothesis both in cultured podocytes of different ApoL1 genotypes and by transfecting podocytes with ApoL1 constructs designed to probe the underlying apoptotic mechanisms. 3. Use a zebrafish model to study ApoL1- mediated renal injury in vivo: We will use zebrafish to understand how ApoL1 variants promote glomerular injury. We have demonstrated that the G1 risk variant increases embryonic lethality and causes glomerular pathology, and that wild type ApoL1 can reverse the pathologic phenotype caused by G1. We will examine the effects of heterologous ApoL1 expression in a whole organism using ubiquitous and tissue-specific promoters. We will define the risk variant domains that cause disease and the wild type domains that prevent G1-mediated injury. We will also define the specific interactions between the wild-type, G1, and G2 forms of ApoL1 in vivo. Lastly, we will examine the role of ApoL1 variants in promoting or preventing apoptosis of glomerular cells.

描述（由申请人提供）：超过50万美国人患有终末期肾病（ESRD）。非裔美国人患ESRD的比率是欧裔美国人的4-5倍。最近，我们发现载脂蛋白l1 （ApoL1）基因的编码序列变异，仅存在于最近非洲血统的个体中，解释了这种健康差异的很大一部分。这一点现已得到多项额外研究的证实。ApoL1变异对不同类型的肾脏疾病有重要影响，包括高血压相关ESRD、局灶节段性肾小球硬化和hiv相关肾病。携带两个ApoL1变异等位基因的人患肾脏疾病的风险增加7-30倍。350万非洲裔美国人可能有高风险的ApoL1基因型。没有两个变异等位基因的非裔美国人的额外风险最小。目前，对ApoL1的生物学及其在肾脏中的作用知之甚少。ApoL1在对锥虫的抗性中具有明确的作用，并且G1和G2变体似乎在非洲已经变得普遍，因为它们赋予对引起非洲昏睡病的锥虫形式的保护。在这里，我们的目标是阐明ApoL1的功能及其在引起人类肾脏疾病中的作用，以了解肾脏疾病风险差异背后的生物学机制。ApoL1是Bcl2家族成员，具有BH3-only结构域，提示可能在细胞凋亡中起作用。我们在卵母细胞中的初步实验使我们相信这一途径可能是apol1相关疾病肾小球损伤的重要机制。我们建议：1。定义ApoL1的细胞生物学和细胞生理学：我们将定义ApoL1的基本细胞生物学，包括生物合成、运输、离子通道特性、内吞作用和对细胞器结构的影响