ARHGAP32基因Leu754Val突变导致局灶节段性肾小球硬化的发病机制研究

局灶节段性肾小球硬化（FSGS）对激素等各种治疗方案反应差，易快速进展为终末期肾病。深入探讨FSGS发病的始动机制是探索新治疗方法的前提和关键所在。遗传因素是FSGS发病的重要原因。我们前期在一个FSGS家系中筛选到一个新的候选致病ARHGAP32。其在FSGS肾组织中表达明显增加。我们又在309例散发FSGS患者发现了2个新突变。我们建立了ARHGAP32基因Leu754Val点突变小鼠，研究发现，突变小鼠对阿霉素损伤的敏感性显著增加。该突变位点在不同物种间高度保守，突变可能导致其GAP功能域异常，影响Rho GTPase的活性，通过干扰细胞骨架形成，导致足细胞损害和FSGS发生。本项目拟通过细胞实验，动物实验，及突变小鼠肾病模型肾小球单细胞表达谱的研究，确立ARHGAP32基因在FSGS发病中的地位，阐明Leu754Val突变导致FSGS的机制，为临床诊断提供依据，为治疗探索提供方向。

Due to its poor response to glucosteroids and other treatment options, focal segmental glomerulosclerosis (FSGS) is prone to rapid progression to end-stage renal disease. Investigation of initial pathogenesis of FSGS is the premise and key point to explore new treatment. Genetic factors play an important role in the pathogenesis of FSGS. Previously, we identified a new candidate pathogenic gene ARHGAP32 in a FSGS pedigree. The arhgap32 expression in renal tissue of FSGS patients increased significantly. We screened two new possibly pathogenic mutations of ARHGAP32 in 309 patients with sporadic FSGS. We established a mouse model with leu754val point mutation of ARHGAP32 gene, and found that the sensitivity of the knockin mice to adriamycin damage increased extremely. The leu754val mutation is the highly conserved among different species.It is speculated that the mutation could lead to the abnormal function of GAP domain, affect the activity of Rho GTPase, and cause podocyte damage and FSGS by interfering with cytoskeleton formation. This project aims to clarify the role of ARHGAP32 gene in the pathogenesis of FSGS, illustrate the mechanism of leu754val mutation leading to FSGS, by in vitro cell experiments, in vivo animal experiments and single cell transcriptome sequencing of glomerulus in the mutant mouse nephropathy model. It would be helpful for clinically genetic diagnosis and future treatment exploration.