Focal segmental glomerulosclerosis: HIV-associated nephropathy

局灶节段性肾小球硬化症：HIV 相关肾病

• 批准号: 10706917
• 负责人: Jeffrey Burnett Kopp
• 金额: $ 52.2万
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10706917
• 关键词: AIDS-Associated Nephropathy; APOL1 gene; Affect; Aftercare; Alleles; Apoptosis; Bacterial Artificial Chromosomes; Biology; Caspase; Cell Line; Cell Proliferation; Cells; Characteristics; Clinical; Desmin; Differentiation Antigens; Doxycycline; Edema; End stage renal failure; Epithelial; Excretory function; Focal and Segmental Glomerulosclerosis; Genes; Genetic; HIV; HIV-1; Hour; Hyperplasia; Hypertrophy; In Vitro; Injury; Kidney; Kidney Diseases; Mineralocorticoid Receptor; Molecular; Mus; NPHS2 protein; Obesity; Parietal; Pathogenesis; Pathologic; Pathway interactions; Patient observation; Patients; Phenotype; Proteins; Proteinuria; Publications; Renal Mass; Risk; Role; Sickle Cell Anemia; Simian virus 40; Sodium; Sodium Channel; South Africa; Syndrome; System; Temperature; Tetracyclines; Transgenes; Transgenic Mice; Transgenic Organisms; Tubular formation; Ursidae Family; Variant; WT1 gene; Work; cell injury; genetic variant; glomerulosclerosis; in vivo; nephrin; podocyte; renal toxin; risk variant; synaptopodin; transgene expression; vpr Gene Products; vpr Genes

Focal segmental glomerulosclerosis (FSGS) is a clinical-pathologic syndromes characterized by the accumulation of fibrotic proteins in glomeruli, initially involving only some glomeruli (focal) and involving portions (segments) of the affected glomeruli. FSGS can be classified as follows: idiopathic FSGS, genetic FSGS and post-adaptive FSGS (associated with glomerular hypertrophy and hyperfiltration, and due to reduced renal mass, renal toxins, obesity, and sickle cell disease). A related syndrome is collapsing glomerulopathy, associated with podocyte hyperplasia whereas FSGS is associated with podocyte depletion. Collapsing glomerulopathy can be classified as HIV-associated or idiopathic. In order to define the molecular mechanisms responsible for HIV-associated collapsing glomerulopathy, we have established mice in which transgene expression can be regulated in the glomerular podocyte using an tetracycline-regulated system. We have used this system to express the HIV-1 accessory protein Vpr in the podocyte. These mice develop proteinuria beginning 4 weeks after treatment with tetracycline. Collapsing glomerulopathy appears at 8 weeks, progressing to global glomerulosclerosis and end-stage kidney disease. Podocyte phenotype is abnormal, with reduced expression of the differentiation marker synaptopodin and de novo expression of the injury marker desmin. Increased cell proliferation is present in the glomerular tuft, parietal epithelium, and tubular epithelium. These results demonstrate that Vpr is sufficient to induce HIV-associated collapsing glomerulopathy in transgenic mice. 1) Using these transgenic mice, we have established double transgenic podocyte cell lines, which bear the podocin/rtTA, and temperature-sensitive SV40 Tag transgenes to confer conditional immortalization. These cells were found to express characteristic podocyte markers, including podocin, nephrin, and WT1. We have introduced the Vpr gene into these cells to understand Vpr-induced cell injury. Our results indicate increased apoptosis with 12 hours of Vpr expression induced by doxycycline. The mechanisms appear to involve both caspase dependent and caspase independent pathways. Recently, we have completed a project in which we show that Vpr increases expression, in vivo (mice) and in vitro of the tubular sodium channel, promoting sodium excretion. This finding explains the clinical observation that patients with HIV-associated nephropathy often lack edema, in contrast to other patients with nephrotic proteinuria. This work will be subjected for publication in the next few months. We are generating generating dual Tg26 mice (containing the six regulatory and accessory genes of HIV-1) X each of three BAC/APOL1 mouse lines (separately encoding each of three APOL1 alleles, two of which predispose to kidney disease). This will allow us to explore the hypothesis that certain HIV genes might amplify the effect of APOL1 kidney risk alleles, either in an additive or super-additive fashion.

局灶性节段性肾小球硬化症（FSGS）是一种临床病理综合征，其特征是纤维化蛋白在肾小球中的积累，最初仅涉及一些肾小球（局灶性），并且涉及受影响的肾小球的部分（段）。 FSG可以分类如下：特发性FSG，遗传FSG和自适应后FSG（与肾小球肥大和过滤相关，以及肾脏质量，肾脏毒素，肥胖症和镰状细胞病）。相关的综合征崩溃的肾小球病，与足细胞增生有关，而FSGS与足细胞耗竭有关。崩溃的肾小球病可以归类为与HIV相关或特发性。 为了定义负责与HIV相关崩溃的肾小球病的分子机制，我们已经建立了小鼠，其中可以使用四环素调节的系统在肾小球足细胞中调节转基因表达。我们已经使用该系统在足细胞中表达HIV-1辅助蛋白VPR。这些小鼠在四环素治疗后4周开始发展蛋白尿。 骨膜病崩溃时出现8周，发展为全球肾小球硬化和终末期肾脏疾病。足细胞表型异常，分化标记突触素的表达降低，并从头表达损伤标志物脱敏蛋白。细胞增殖增加存在于肾小球簇，顶叶上皮和管状上皮。这些结果表明，VPR足以在转基因小鼠中诱导与HIV相关的崩溃肾小球病。 1）使用这些转基因小鼠，我们已经建立了带有Podocin/rtTA的双转基因足细胞系，并建立了对温度敏感的SV40 TAG转基因，以赋予有条件的永生化。发现这些细胞表达了特征性的足细胞标记物，包括Podocin，Nephrin和WT1。我们已将VPR基因引入这些细胞，以了解VPR诱导的细胞损伤。 我们的结果表明，通过强力霉素诱导的12小时的VPR表达增加了凋亡。 这些机制似乎涉及caspase依赖性和caspase独立途径。 最近，我们完成了一个项目，在该项目中，我们表明VPR增加了体内（小鼠）和肾小管钠通道体外的表达，从而促进钠排泄。这一发现解释了临床观察结果，与其他肾病蛋白尿患者相比，与HIV相关的肾病患者通常缺乏水肿。这项工作将在接下来的几个月内进行出版。 我们正在产生双重TG26小鼠（含有HIV-1的六个调节和辅助基因）X x三种BAC/APOL1小鼠系中的每个小鼠（分别编码三个ApoL1等位基因中的每个等位基因，其中两种易于肾脏疾病）。这将使我们能够探讨以下假设：某些HIV基因可能会以添加剂或超级添加的方式扩大Apol1肾脏风险等位基因的影响。