Identifying the earliest events in HIV-1 associated nephropathy via genome-wide

描述(申请人提供)：这个项目的目标是使用一个有效的小鼠模型来剖析介导HIV-1相关性肾病(HIVAN)发展的分子途径。HIVAN是HIV-1感染的主要并发症，具有鲜明的病理特征。这种疾病是由HIV-1诱导的肾小球足细胞去分化引起的，足细胞是维持肾滤过屏障结构的终末分化的上皮细胞。HIVAN的遗传易感性有复杂的决定因素，非肌肉肌球蛋白重链9(Myh9)的遗传变异对HIVAN有重要影响，Myh9是足细胞表达的基因。FVB/NJ基因背景的HIV-1转基因小鼠概括了HIVAN的所有临床和病理特征。利用对HIVAN易感性不同的小鼠之间的作图队列，我们已经确定了三个分别映射到第3、13、4号染色体(命名为HIVAN1-3)的肾病易感基因座，并通过对捕获这些间隔的同源小鼠的检查确认了作图数据。通过结合F2分离株的连锁分析和基因表达谱(eQTL定位)，我们还证明了小鼠HIVAN易感基因编码足细胞基因表达的反式调节因子，并与已知的人类肾病基因(Myh9、Podocin、Neph in、CD2AP)属于相同的途径。HIV-1的引入导致了特定足细胞基因组的基因型和表达之间的关系的显著扰动，表明HIV-1干扰了反式调节。这些考虑表明，仔细分析与每个HIVAN基因座相关的临床和分子表型，并识别在对HIV-1暴露的反式调节中表现出最大扰动的基因，可以阐明肾病发生的最早事件，并描绘出介导疾病发病机制的失调的分子网络。为了实现这些目标，我们将首先对HIVAN同源基因小鼠进行表型鉴定，以确定每个基因座对疾病的发生和发展的贡献。接下来，我们将对HIV-1转基因同基因小鼠和野生型小鼠的肾小球转录组进行分析，以推断HIVAN中的肾小球相互作用组，并发现显示反式调节异常模式的基因。最后，这些基因将通过在HIVAN分离物中进行eQTL定位，通过对人类足细胞的功能研究，并最终通过产生证实发现的转基因品系来验证。识别HIVAN的分子介质有望为疾病的发病机制提供重要的洞察力，并为治疗干预提供新的靶点。 公共卫生相关性：HIV-1相关性肾病是HV-1感染的主要并发症，也是全球肾功能衰竭的重要原因。识别HIVAN的分子介质有望为疾病的发病机制提供重要的洞察力，并为治疗干预提供新的靶点。

DESCRIPTION (provided by applicant): The goals of this project are to use a validated mouse model to dissect molecular pathways mediating he development of HIV-1 associated nephropathy (HIVAN). HIVAN is a major complication of HIV-1 infection with distinct pathologic features. This disorder is caused by HIV-1 induced dedifferentiation of glomerular podocytes, the terminally differentiated epithelial cells that maintain the structure of the kidney filtration barrier. Genetic susceptibility to HIVAN has complex determination, with significant contribution from genetic variation in the nonmuscle myosin heavy chain 9 (MYH9), a podocyte expressed gene. HIV-1 transgenic mice on the FVB/NJ genetic background recapitulate all the clinical and pathologic hallmarks of HIVAN. Using mapping cohorts between mice with contrasting susceptibility to HIVAN, we have identified three nephropathy susceptibility loci that map to chromosomes 3, 13, 4 respectively (named HIVAN1- 3) and have confirmed mapping data by examination of congenic mice that capture these intervals. By combining linkage analysis with gene expression profiling (eQTL mapping) in F2 segregants, we have also demonstrated that the murine HIVAN susceptibility loci encode transregulators of podocyte gene expression and belong to the same pathway as known human nephropathy genes (Myh9, Podocin, Nephrin, Cd2ap). The introduction of HIV-1 results in significant perturbations of the relationship between genotype and expression of specific sets of podocyte genes, indicating that HIV-1 interferes with transregulation. These considerations indicate that careful dissection of clinical and molecular phenotypes associated with each HIVAN locus and identifications of genes that demonstrate the greatest perturbation in transregulation upon HIV-1 exposure can elucidate the earliest events in the initiation of nephropathy and delineate dysregulated molecular networks mediating disease pathogenesis. To achieve these aims, we will first perform phenotypic characterization of HIVAN congenic mice to identify the contribution of each locus to initiation and progression of disease. Next we will perform analysis of glomerular transcriptome in HIV-1 transgenic congenic mice and wiltype counterparts to infer the glomerular interactome in HIVAN and discover genes that demonstrate aberrant patterns of transregulations. Finally, these genes will be validated by eQTL mapping in HIVAN segregants, by functional studies in human podocytes and ultimately, by generation of transgenic lines that will confirm findings. Identification of molecular mediators of HIVAN is expected to provide significant insight into the pathogenesis of disease and provide novel targets for therapeutic intervention. PUBLIC HEALTH RELEVANCE: HIV-1 associated nephropathy is a major complication of HV-1 infection and a significant cause of kidney failure worldwide. Identification of molecular mediators of HIVAN is expected to provide significant insight into the pathogenesis of disease and provide novel targets for therapeutic intervention.