Role of CD2AP in Human Glomerular Disease

描述(申请人提供)：CD2AP是一种80kD的蛋白质，被克隆为参与T细胞激活的蛋白质。CD2AP在肾脏中也起着重要作用。CD2AP基因敲除小鼠出生时患有先天性肾病综合征，CD2AP表达于肾小球上皮细胞或足细胞。我们以前的工作表明，CD2AP在维持裂隙隔膜的完整性方面发挥着关键作用，裂隙隔膜是肾小球滤过装置中的一个关键结构。 最近，我们发现我们的CD2AP杂合子小鼠表现出对肾毒性抗体引起的肾脏损伤的易感性增加，或者当饲养到NZB小鼠时。提示CD2AP杂合性可能在人类肾小球疾病中起一定作用。在我们的初步工作中，我们已经确定了被诊断为局灶性节段性肾小球硬化的人类患者，他们是CD2AP杂合子。 在这项拨款申请中，我们建议通过分析更大范围的FSGS患者CD2AP突变来扩展这些研究。在前两个目标中，我们建议识别CD2AP的遗传变异并确定它们在人群中的流行率。在目标#3中，我们提出了一系列实验来确定这些突变是否致病，通过生化测试CD2AP突变形式，通过它们在CD2AP缺陷细胞系中转染后重建功能的能力，以及它们拯救基因敲除小鼠肾脏表型的能力。我们希望这些研究能对肾小球疾病有新的认识。

DESCRIPTION (provided by applicant): CD2AP is an 80 KD protein that was cloned as a protein involved in T cell activation. CD2AP also plays a major role in the kidney. CD2AP knockout mice are born with congenital nephritic syndrome and CD2AP is expressed in the glomerular epithelial cell or podocyte. Our previous work suggests that CD2AP plays a critical role in maintaining the integrity of the slit diaphragm, a structure that is critical in the glomerular filtration apparatus. Recently, we discovered that our CD2AP heterozygous mice demonstrate an increased susceptibility to renal injury caused by nephrotoxic antibodies or when bred to the NZB mouse. This suggested that CD2AP heterozygosity might play a role in human glomerular disease. In our preliminary work, we have identified human patients with the diagnosis of focal segmental glomerulosclerosis who are heterozygous for CD2AP. In this grant application, we propose to extend these studies by analyzing a larger population of patients with FSGS for mutations in CD2AP. In the first two aims, we propose to identify genetic variants of CD2AP and determine their prevalence in the population. In aim #3, we propose a series of experiments to determine whether these mutations are disease causing, by testing mutated forms of CD2AP biochemically, by their ability to reconstitute function after transfection in CD2AP deficient cell lines and by their ability to rescue the renal phenotype of the knockout mouse. We hope that these studies lead to new insights into diseases of the glomerulus.