Biological Mechanism of familial focal segmental glomeru

家族性局灶节段性肾小球的生物学机制

• 批准号: 6856505
• 负责人: MARTIN R. POLLAK
• 金额: $ 34.45万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6856505
• 关键词: alpha actinin; biopsy; clinical research; disease /disorder model; embryonic stem cell; epithelium; gene targeting; glomerulosclerosis; human subject; laboratory mouse; molecular pathology; protein localization; protein protein interaction; tissue /cell culture

DESCRIPTION (Adapted from the Applicant's Abstract): We have recently demonstrated that mutations in ACTN4, encoding a-actinin-4, cause an autosomal dominant form of familial focal and segmental glomerulosclerosis, a-actinin-4 is a member of a group of homodimeric actin crosslinking proteins. Our data suggests that these mutations act in a gain-of-function manner to disrupt normal glomerular epithelial cell function. The precise mechanism by which these mutations cause disease is unclear. We do not know if the mutations cause clinical disease through the altered interaction of actinin with actin we have observed, through an alteration in the interaction of actinin with some other protein or proteins, or by some other effect. In this proposal, we aim to gain additional understanding into the pathobiology of this form of FSGS. There are three basic aims of this proposal. We first will examine the interaction of mutant actinins with actin in both in vitro and in cell culture. We will produce mutant a-actinin-4 and measure its interaction with actin filaments as well as with a-actinin itself. We will observe the effect of transfecting mutant ACTN4 constructs on the actinin localization and the actin cytoskeleton. Next, we will examine the effect of these mutations on the interactions of a-actinin-4 with two other proteins which are thought to be important in podocyte structure and function, b1-integrin and a-catenin. Thirdly, we will develop a mouse model of this form of focal segmental glomerulosclerosis using methods of homologous recombination in embryonic stem cells. We will replace the endogenouse mouse actn4 gene with a gene harboring a missense point mutation identified as disease-causing in one large human pedigree. This model will allow us to investigate the pathobiology of this disease in vivo. The phenotype in patients with this familial form of FSGS is similar to the secondary glomerulosclerosis seen with many underlying conditions, including diabetes and hypertension. We therefore believe that these studies will provide significant insight into both the role of actinin and the actin cytoskeleton in the podocyte as well as in mediating chronic progressive renal dysfunction.

描述（改编自申请人的摘要）：我们最近 证明了编码α-辅肌动蛋白-4的ACTN 4突变导致常染色体显性遗传。 家族性局灶性和节段性肾小球硬化症的主要形式，α-辅肌动蛋白-4 是一组同型二聚体肌动蛋白交联蛋白的成员。我们的数据 表明这些突变以功能获得的方式破坏 肾小球上皮细胞功能正常。的确切机制 这些突变导致的疾病尚不清楚。我们不知道突变是否会导致 临床疾病通过改变相互作用的肌动蛋白与肌动蛋白，我们有 观察到，通过改变辅肌动蛋白与其他一些 蛋白质或蛋白质，或通过一些其他作用。在这项提案中，我们的目标是获得 进一步了解这种形式的FSGS的病理生物学。 这项建议有三个基本目标。首先，我们将研究 在体外和细胞培养中突变辅肌动蛋白与肌动蛋白的相互作用。 我们将产生突变的α-辅肌动蛋白-4，并测量其与肌动蛋白的相互作用 以及α-辅肌动蛋白本身。我们将观察 在辅肌动蛋白定位和辅肌动蛋白表达上的转染突变型ACTN 4构建体 细胞骨架接下来，我们将研究这些突变对 α-辅肌动蛋白-4与其他两种蛋白质的相互作用， 在足细胞结构和功能中重要的β 1-整联蛋白和α-连环蛋白。 第三，我们将建立一个小鼠模型，这种形式的局灶节段性 使用胚胎干中的同源重组方法的肾小球硬化症 细胞我们将用一个携带一个基因的基因替换内源性小鼠actn 4基因。 错义点突变被确定为在一个大型人类中致病 血统这个模型将使我们能够研究这种疾病的病理学 体内疾病 这种家族性FSGS患者的表型与 继发性肾小球硬化症，见于许多基础疾病，包括 糖尿病和高血压。因此，我们认为，这些研究将提供 对辅肌动蛋白和肌动蛋白细胞骨架的作用的重要见解， 以及介导慢性进行性肾功能不全。