Intracellular functions of APOL1 in the kidney

APOL1 在肾脏中的细胞内功能

基本信息

批准号：
10383979
负责人：
Leslie A Bruggeman
金额：
$ 56.49万
依托单位：
CLEVELAND CLINIC LERNER COM-CWRU
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-23 至 2026-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10383979
关键词：
AIDS-Associated Nephropathy Advanced Development Advocate African American Alleles Apolipoproteins Attenuated Bacterial Artificial Chromosomes Biochemical Biochemical Pathway Biological Models Biological Process Cell Adhesion Cell Line Cell Survival Cells Chronic Kidney Failure Clinical Clustered Regularly Interspaced Short Palindromic Repeats Data Development Disease Disease model Endosomes Environment Event Exposure to Focal Segmental Glomerulosclerosis Functional disorder Future Gene Expression Gene Expression Profiling Genes Genetic Genetic Polymorphism Genetic Predisposition to Disease Genetic Risk Genetic Transcription Genotype Goals HIV HIV Infections Human Hypertension IRF3 gene Immune Immune response Immune signaling In Vitro Individual Inheritance Patterns Inherited Injections Injury Interferons Investigation Kidney Kidney Diseases Knock-out Link Lupus Nephritis Mediating Methods Modeling Mus Outcome Study Pathogenesis Pathogenicity Pathology Pattern recognition receptor Phenotype Poly I-C Prevalence Prevention strategy Process Receptor Activation Renal function Risk Role Signal Transduction Stimulus Stress TLR3 gene Testing Time Toll-like receptors Transgenic Mice United States Variant Vesicle Virus Virus Diseases Work adaptive immune response biological adaptation to stress cytotoxicity density disease stressor disorder risk environmental stressor gain of function gene environment interaction genetic variant high risk immune activation in vivo in vivo Model induced pluripotent stem cell innate immune pathways kidney biopsy loss of function mouse model non-diabetic novel novel therapeutics podocyte protective effect racial health disparity recessive genetic trait response risk variant stressor targeted treatment therapy design trafficking trait treatment strategy

项目摘要

ABSTRACT Chronic kidney disease (CKD) in African Americans is one of the largest racial health disparities in the United States. The cause for the increased risk has been attributed to recessive inheritance of allelic variants in the gene for apolipoprotein L1 (APOL1). These APOL1 variants, known as G1 and G2, do not cause CKD on their own, but CKD is caused by a combination of the inherited genetic risk plus exposure to a triggering environmental stressor (a gene-environment interaction). Despite the association of CKD risk with APOL1 variants more than ten years ago, the biological function of APOL1 in the kidney and the mechanism of pathogenesis in the setting of a disease stressor remain unclear. Our long-term goal is to understand the genetics and biochemical mechanism of CKD in African Americans caused by these APOL1 polymorphisms. To accomplish this goal, we are studying HIV-associated nephropathy (HIVAN), the CKD most strongly associated APOL1 variants, and the only CKD where the environmental stressor is known (HIV infection). HIVAN is an ideal disease model to dissect biochemical pathways and cellular events intersected by APOL1 function, viral infection, and CKD. Our recent studies have demonstrated, for the first time, a function for the common APOL1 allele, known as G0, in providing protection against podocyte losses in HIVAN. Since APOL1 risk is a recessively inherited trait, this suggests CKD may be caused, in part, by a loss-of-function process (i.e. absence of G0). In new preliminary data, G0 appears to associate with Toll-like receptors (TLRs) in intracellular vesicles containing HIV and facilitate signaling events initiated by interferon regulatory factor (IRF)-3, and these processes were absent with the APOL1 risk variants. Methods will use established in vitro HIV infection of human podocyte cell lines, in vivo models of HIVAN and BAC-APOL1 transgenic mice that replicate endogenous human APOL1 expression. Aims will examine both initial response to HIV infection in podocytes, and long-term in vivo studies of intercrosses between the HIVAN and BAC-APOL1 transgenic mice evaluating effects on renal function and pathology. These studies also will establish temporal and magnitude of stressor-induced APOL1 expression, the mechanism of the altered innate immune activation through TLRs to IRF-3/7 signaling, and effect on podocyte phenotype (survival and cell adhesion). The dominance of the G0 protective effect over the risk variant dysfunction will be tested in podocytes and mouse models co-expressing G0 and the risk variants. These studies should advance our understanding of gain- versus loss-of-function mechanism associated with the recessive inheritance of APOL1 risk alleles, and the necessity of induced APOL1 expression to drive stress responses. Determining the contribution of G0 function versus risk variant dysfunction will have important clinical impact on further therapy design, as it will establish whether replacement of G0 or suppression of the risk variants would be the more effective strategy.

抽象的非裔美国人的慢性肾病（CKD）是美国最大的种族健康差异之一国家。风险增加的原因归因于等位基因变异的隐性遗传载脂蛋白 L1 (APOL1) 基因。这些 APOL1 变体（称为 G1 和 G2）不会导致其自身的 CKD 但 CKD 是由遗传风险加上暴露于触发性环境共同引起的压力源（基因与环境的相互作用）。尽管 CKD 风险与 APOL1 变异的关联超过十年前，APOL1在肾脏中的生物学功能及其发病机制疾病应激源的作用仍不清楚。我们的长期目标是了解遗传学和生化 APOL1 多态性导致非裔美国人 CKD 的机制。为了实现这一目标，我们正在研究 HIV 相关肾病 (HIVAN)、CKD 最强相关的 APOL1 变异以及仅在已知环境压力源（HIV 感染）的情况下发生 CKD。 HIVAN 是一个理想的疾病模型来剖析 APOL1 功能、病毒感染和 CKD 交叉的生化途径和细胞事件。我们最近的研究首次证明了常见的 APOL1 等位基因（称为 G0）的功能，可提供防止 HIVAN 中足细胞损失。由于 APOL1 风险是一种隐性遗传特征，这表明 CKD 可能部分是由功能丧失过程（即 G0 缺失）引起的。在新的初步数据中，G0 似乎与含有 HIV 的细胞内囊泡中的 Toll 样受体 (TLR) 相关并促进信号传导由干扰素调节因子 (IRF)-3 引发的事件，并且这些过程在 APOL1 风险中不存在变体。方法将使用建立的体外HIV感染的人类足细胞细胞系、HIVAN的体内模型以及复制内源性人类 APOL1 表达的 BAC-APOL1 转基因小鼠。目标将检查两者足细胞对 HIV 感染的初步反应，以及 HIVAN 之间交叉的长期体内研究和 BAC-APOL1 转基因小鼠评估对肾功能和病理学的影响。这些研究也将确定应激源诱导的 APOL1 表达的时间和强度，即先天性改变的机制通过 TLR 对 IRF-3/7 信号传导进行免疫激活，并对足细胞表型（存活和细胞附着力）。 G0 保护作用相对于风险变异功能障碍的主导作用将在足细胞中进行测试以及共表达 G0 和风险变异的小鼠模型。这些研究应该增进我们对与 APOL1 风险等位基因隐性遗传相关的功能获得与丧失机制，以及诱导 APOL1 表达来驱动应激反应的必要性。确定 G0 的贡献功能与风险变异功能障碍将对进一步的治疗设计产生重要的临床影响，因为它将确定替换 G0 或抑制风险变异是否是更有效的策略。