Exosomal miR-193a介导的足细胞自噬障碍在促进FSGS形成中的作用及相关机制研究

Focal segmental glomerulosclerosis (FSGS) is the most common primary glomerular histologic lesion associated with refractory nephrotic syndrome and with ESRD in children. It is diagnosed by renal biopsy, in which characteristic feature is podocyte damage. Therefore, insights into the mechanisms responsible for podocyte coping with stress are important to understand the pathogenesis of FSGS and improve its prognosis. Our previous research supported by NSFC demonstrates a podocytoprotective role of autophagy under complement-mediated stress condition. However, to date, the role of autophagy in the progression of podocytopathy of FSGS and how this catabolic process is regulated is essentially unknown. This study consists of two parts: analyses of patients’ tissue and urine specimens, and in vitro cell experiments. We will adopt a variety of experimental methods, such as construction of lentiviral vector, exosome separation, RNA-Seq, qRT-PCR, luciferase reporter assay, transmission electron microscope imaging, patch clamp recording and so on to clarify how autophagy is regulated by miR-193a in podocyte, the mechanisms whereby exosomes mediate the podocyte-to-podocyte expansion of injury, the molecular mechanisms whereby miR-193a are sorted to exosomes in podocyte, and the intracellular signaling pathways regulating the exosomes secretion of podocyte. These results are very important to clarify the pathogenesis of FSGS and hamper the progression of renal fibrosis.

局灶节段性肾小球硬化（FSGS）是儿童难治性肾病综合征和终末期肾脏病最常见的病因之一。“足细胞损伤”为其核心病变并与之预后密切相关，因此探讨足细胞的损伤修复机制及其调控通路对阐明FSGS发病机理及改善预后至关重要。前期在NSFC资助下我们发现在免疫介导的足细胞损伤过程中，自噬是维系足细胞表型和生存至关重要的修复机制。但目前对FSGS患者足细胞自噬应答及其调控机制的认识有限。本课题拟通过临床标本分析和体外细胞学实验，探讨miR-193a对足细胞自噬的影响及其作用的分子机制，以及exosomes介导足细胞间损伤传递的分子基础，并进一步探讨介导miR-193a在足细胞内异常升高及其向exosomes选择性聚集的分子事件，以及调控足细胞exosomes分泌的细胞内信号通路，最终阐明自噬在FSGS足细胞病变过程中的角色及其相关的分子调控机制，为深入认识FSGS发病机制和阻断肾脏纤维化进展提供新思路。

局灶节段性肾小球硬化（FSGS）是儿童难治性肾病综合征和终末期肾脏病最常见的病因之一。“足细胞损伤”为其核心病变并与之预后密切相关，因此探讨足细胞的损伤修复机制及其调控通路对阐明FSGS发病机制及改善预后至关重要。我们前期工作发现在补体介导的足细胞损伤过程中，自噬是维系足细胞表型和生存至关重要的修复机制。故而本项目以此为切入点，通过构建PHN足细胞病模型，发现自噬是维持足细胞稳态的重要损伤应答机制，自噬障碍将导致足细胞病加重。继而通过细胞学实验和miR-155-/-鼠的阿霉素肾病模型，发现外泌体可介导足细胞之间的信息传递，其内含物miRNAs可调控受体细胞的表型和功能，多种miRNAs（如miR-155，miR-193a等）均可影响足细胞的存活、自噬；而足细胞外泌体的分泌受细胞内钙信号调控。此外，我们通过临床样本分析，证实尿外泌体miR-193a可作为FSGS鉴别诊断和预后判断的一种标志物。上述结果阐明了自噬障碍参与足细胞病的发生，外泌体介导的细胞间miRNAs传递可调控足细胞的自噬应答，而且尿液中外泌体miRNAs还可作为无创诊断和判断预后的标志物，从而为深入认识FSGS发病机理及探寻新的治疗措施提供依据。