足细胞损伤是导致蛋白尿和肾小球硬化的重要病理基础。我们前期研究发现线粒体功能障碍(MtD)是足细胞损伤的起始事件，但MtD的发生机制尚不清楚。课题组研究发现miR-214富集于线粒体中，且在醛固酮灌注小鼠肾组织中表达显著增加，过表达miR-214诱导MtD和足细胞凋亡，生物信息学分析提示线粒体ATPase8是其潜在靶基因；miR-214启动子中含有Oct-1结合位点，过表达Oct-1促进线粒体miR-214表达。由此设想CKD时肾组织中Oct-1活化，诱导miR-214表达，miR-214从胞浆转运并富集到线粒体中，抑制线粒体ATPase8表达，诱导MtD和足细胞损伤。本研究将鉴定miR-214靶基因ATPase8，并应用过表达和沉默技术阐明miR-214在诱导MtD和足细胞损伤中的作用及其机制；明确Oct-1对miR-214表达调控及其是否通过诱导miR-214而促进MtD和足细胞损伤。

Podocyte injury is one of the critical events leading to proteinuria and glomerulosclerosis. Our previous study indicated that mitochondrial dysfunction is an early event and iniates podocyte injury. However, the molecular mechanism involved in mitochondrial dysfunction remains unclear. To determine which miRNA species may be involved in inducing mitochondrial dysfunction, we first compared miRNA expression profiles in renal cortex cytosol and mitochondria from aldosterone-infused mice. Microarray analysis and further real-time PCR analysis indicated that miR-214 was enriched and unregulated in mitochondria. Moreover, upregulation of miR-214 precedes the mitochondrial dysfunction and podocyte injury. Overexpression of miR-214 by lentivirus-miR-214 induced mitochondrial dysfunction and podocyte injury in cultured podocytes. Informatic analysis predicted 3'-UTR of ATPase contains conserved critical nucleotides that may serve as a legitimate target of miR-214. In a series of preliminary experiments, we found that the promoter of miR-214 gene contains three binding sites for transcription factor Oct-1. Overexpression of Oct-1 could increase mitochondrial miR-214 expression in podocytes. Therefore, we hypothesized that activation of Oct-1 in CKD unregulated mitochondrial miR-214 expression, which induced mitochondrial dysfunction and podocyte injury by inhibition of mitochondrial ATPase8 expression. To test this hypothesis, we firstly identify that miR-214 directly targets the 3'-UTR of ATPase8 and induces mitochondrial dysfunction and podocyte injury by overexpression and RNAi strategy. Secondly, it will be determined whether Oct-1 binds to miR-214 promoter by using independent Chromosome Immunoprecipitation (ChIP) PCR, Electrophoretic Mobility Shift Assay (EMSA) and luciferase reporter system assay. Finally, the effect of miR-214 will be observed on Oct-1-reduced MtD and podocyte injury by specific anti-miR-214 inhibitor. Together, the present study highlights a new role for Oct-1/miR-214 signaling pathway in mitochondrial dysfunction and podocyte injury, which may guide us in therapeutic strategies for CKD.