miR-214趋向性过表达下调Hippo-YAP信号通路节点LATS2介导骨关节炎软骨“衰老”的机制

The “aging” of behavioral and functional characteristics of chondrocyte plays a critical role in the pathogenesis of OA (osteoarthritis), yet the underlying mechanism of “aging” is still under investigation. As demonstrated, the Hippo-YAP signaling pathway is essential for maintaining the phenotype of cartilage, and the stability of chondrocyte behavior as well as its function. Our recent studies have found that the expression of miR-214 is high in cartilage of the OA patients and OA-mice model, and knockout of miR-214 using knockout mice showed protective effect on the “aging” of OA cartilage; there is a negative regulation of LATS2 of the Hippo-YAP signaling pathway by miR-214 in chondrocyte. We therefore hypothesize that the overexpression of miR-214 inhibits LATS2 and the Hippo-YAP signaling pathway thus is involved in the “aging” of OA cartilage. In order to verify the hypothesis, we will reveal the inhibitory mechanism of LATS2 of the Hippo-YAP signaling pathway by miR-214 using reporter genes, quantitative PCR and immunostaining in vitro, and elucidate biological functions and significances of the regulation of miR-214 in the inhibition of LATS2 in the “aging” of OA cartilage using miR-214 knockout mice in vivo. The expected results will reveal the pathogenesis of OA from the perspective of miR-214 and the Hippo-YAP signaling pathway, and provide a new theoretical and experimental evidence for the targeted treatment of OA.

软骨细胞行为及功能特征的“衰老”在OA发病中起关键作用，然而其“衰老”机制仍不明确。研究表明，Hippo-YAP信号通路的失活对维持软骨表型，稳定软骨细胞行为及功能特征密切相关。我们近期研究发现：miR-214在OA患者及小鼠模型中趋向性过表达；全基因敲除小鼠发现miR-214调控软骨“衰老”，且软骨细胞中miR-214负调控Hippo-YAP信号关键节点LATS2。据此推测miR-214的趋向性过表达通过靶向LATS2抑制Hippo-YAP信号通路，从而影响OA软骨细胞行为及功能。本研究拟通过体外干预miR-214表达，采用报告基因、荧光定量PCR及免疫荧光证明之，借助全基因敲除小鼠从体内验证miR-214靶向LATS2影响OA软骨“衰老”的生物学作用及意义。本项目有望以miR-214及Hippo-YAP信号通路为视角阐明OA软骨“衰老”的机制，为其靶向治疗提供新理论及实验依据。

软骨细胞行为及功能特征的“衰老”在OA发病中起关键作用，然而其“衰老”机制仍不明确。研究表明，Hippo-YAP信号通路的失活对维持软骨表型，稳定软骨细胞行为及功能特征密切相关。我们近期研究发现miR-214在OA患者及小鼠模型中趋向性过表达。本项目探讨miR-214靶向LATS2介导Hippo-YAP信号通路参与OA软骨“衰老”的机制，对Hippo-YAP上下游信号通路及具体分子机制作了深入的探索。证实了miR-214 在OA患者关节软骨以及小鼠OA模型软骨中的表达增加；miR-214促进软骨细胞相关胶原Col2A1的分解代谢；敲除miR-214能延缓小鼠膝关节软骨的退变以及骨关节炎的进展；利用报告基因技术证实，miR-214结合到LATS2 的3’UTR 序列抑制LATS2的表达，进而激活Hippo/YAP信号通路，增加YAP的表达，利用慢病毒在人软骨细胞中过表达YAP， 通过衰老相关的β半乳糖苷酶染色发现，过表达YAP抑制软骨细胞衰老，而利用慢病毒敲低YAP会促进软骨细胞衰老。通过测序发现并验证YAP通过miR-93调控p21的表达介导软骨表型细胞的衰老。本项目有望以miR-214及Hippo-YAP信号通路为视角阐明OA软骨“衰老”的机制，为其靶向治疗提供新理论及实验依据，具有比较重要的临床意义及科研应用价值。