Nrf2-miR-181c-Notch信号通路逆转慢性CsA肾病肾脏纤维化的作用及机制

CsA plays important roles in the development of kidney injury and renal fibrosis. However, the molecular mechanisms by which CsA induced tubular injury remain largely unknown. We previously performed Oligonucleotide Array-based miRNA Assay of human proximal tubular epithelial cell line by CsA in 24h or parental cells, and we found that the changed expression of miR-181c is most remarkable. Our previously results showed that compared with the CsA/Nrf+/+ mice, the degree of kidney injury was more serious in CsA/Nrf-/- mice kidney tisuess, and the further study finding demonstrated that overexpression of miR-181c could reverse the kidney injury and renal fibrosis. Taken together, our results revealed that miR-181c and Nrf2 play important roles in regulating CsA-induced renal fibrosis. Bioinformatics analysis demonstrated that Nrf2 could bind to the promoter of miR-181c. Thus, we postulated that Nrf2 may directly regulate the expression of miR-181c, thereby regulating the downstream target genes and leading to renal fibrosis. This study aim to testify this hypothesis by in vivo and in vitro experiments. This finding will provided a new insight into the pathogenesis of CsA-induced kidney injury and lay an attractive target for progression of renal disease therapy.

CsA(环孢素A)诱导的肾小管损伤是肾脏纤维化进展的重要原因，但其分子机制仍未完全阐明。我们采用miRNA芯片技术，对CsA干预的HK2细胞及亲本HK2细胞进行高通量筛选，结果提示miR181c表达差别最为显著。预实验结果发现，CsA诱导小鼠肾脏损伤，Nrf2-/-小鼠肾脏损伤及纤维化程度更严重，利用慢病毒过表达miR181c可改善CsA/Nrf2-/-小鼠肾脏损伤及纤维化程度，提示miR181c与Nrf2在肾纤维化进展过程中发挥了重要作用。那么miR181c与Nrf2之间有什么关联？为此进行了生物信息学分析，结果发现编码miR181c的启动子区存在2个Nrf2潜在作用位点。由此推测CsA干预后，miR181c很可能受Nrf2的直接转录调控，进而调控其下游靶基因导致肾小管发生纤维化。本课题将通过体内外实验证实这一理论，这将为慢性CsA性肾脏纤维化机制提供全新视角，为其治疗丰富理论基础。

CsA(环孢素A)诱导的肾小管损伤是肾脏纤维化进展的重要原因，但其分子机制仍未完全阐明。我们采用miRNA芯片技术，对CsA干预的HK2细胞及亲本HK2细胞进行高通量筛选，结果提示miR181c表达差别最为显著。CsA诱导小鼠肾脏损伤，Nrf2-/-小鼠肾脏损伤及纤维化程度更严重，利用慢病毒过表达miR181c可改善CsA/Nrf2-/-小鼠肾脏损伤及纤维化程度，提示miR181c与Nrf2在肾纤维化进展过程中发挥了重要作用。那么miR181c与Nrf2之间有什么关联？为此进行了生物信息学分析，结果发现编码miR181c的启动子区存在2个Nrf2潜在作用位点，我们进一步应用分子生物学方法（荧光素酶报告系统、RT-PCR、染色质免疫共沉淀）验证了CsA抑制 miR-181c 启动子活性依赖Nrf2结合位点，我们同样应用分子生物学方法证实Notch2是miR-181c的一个靶分子，miR-181c-Nrf2-Notch2信号通路通过抑制EMT方式参与了逆转肾脏纤维化过程。本课题的研究为慢性CsA性肾脏纤维化机制提供全新视角，为其治疗丰富理论基础。