血管活性肠肽在骨关节炎中通过RelA-lncRNA CTPS互反馈环路抑制软骨基质降解的机制研究

Osteoarthritis (OA) is a common degenerative disease in the elderly, which seriously endangers the physical and mental health of the old population. The core pathological process of OA is chondrocyte apoptosis and matrix degradation. Applicant has previously found that vasoactive intestinal peptide (VIP) inhibits NF-κB pathway and attenuates the degradation of OA. Further, through gene chip analysis, binding site prediction and in vitro validation, the applicant provides the hypothesis that NF-κB RelA subunit may transcriptionally activate lncRNA CTPS, which mediates miR-26a/138 feedback and enhances RelA activity, and finally up-regulates EZH2 and participates in OA progression; VIP may block the RelA-lncRNA CTPS mutual feedback loop to inhibit cartilage matrix degradation. The applicant will firstly verify the correlation between lncRNA CTPS and OA in human tissues; then investigate the NF-κB RelA/lncRNA CTPS/miR-26a/138 loop and the lncRNA CTPS/ miR-26a/138/EZH2 axis from the cellular level. The function of the loop in OA progression and VIP efficacy was finally determined at the in vivo and in vitro levels. This project will help us clarify the mechanism of action of VIP and provide new perspectives for OA prevention and treatment.

骨关节炎（OA）是常见老年退行性疾病，严重危害中老年人身心健康。OA的核心病理过程是软骨细胞凋亡和基质降解。申请人前期发现血管活性肠肽（VIP）可抑制NF-κB通路延缓OA软骨基质降解。进一步通过芯片分析、结合位点预测及细胞验证，提出假设：NF-κB RelA亚基可转录激活lncRNA CTPS，后者介导miR-26a/138反馈增强RelA活性，最终上调EZH2，参与OA进展；而VIP可阻断RelA-lncRNA CTPS互反馈环路抑制软骨基质降解。本项目拟首先验证临床组织中lncRNA CTPS与OA的相关性；再从细胞水平研究NF-κB RelA/lncRNA CTPS/ miR-26a/138环路以及lncRNA CTPS/ miR-26a/138/EZH2作用轴；最终在体内、体外水平明确该环路在OA进展和VIP疗效中的功能，以阐明VIP的作用机制，为OA防治提供新思路。

骨关节炎（OA）是常见老年退行性疾病，严重危害中老年人身心健康。OA的核心病理过程是软骨细胞凋亡和基质降解。申请人前期发现具有强效抗炎作用的免疫抑制神经肽—血管活性肠肽（VIP）可抑制NF-κB通路延缓OA软骨基质降解，但其作用机制不明。通过微阵列芯片数据和生物信息学分析OA软骨中差异表达的lncRNA，并结合临床组织、细胞和动物模型进行验证，结果发现LOC727924（LINC02203）在OA软骨组织和软骨细胞中上调，并主要富集于细胞质中。在OA软骨细胞中，敲低LOC727924可提高细胞活力、抑制细胞凋亡，增加Aggrecan和Collagen II，降低MMP-3/13、ADAMTS-4/5以及TNF-α、IL-1β和IL-6等细胞因子水平。机制上，LOC727924可以通过竞争性靶向miR-26a，从而下调miR-26a并上调KPNA3，从而与miR-26a/KPNA3轴相互作用；在OA软骨细胞中，miR-26a抑制部分消除了LOC727924对细胞增殖、ECM蛋白和炎症因子的调控作用。miR-26a通过靶向KPNA3和p65转录激活的LOC727924抑制p65的核易位，从而形成p65-LOC727924-miR-26a/KPNA3-p65反馈环路来调节OA软骨细胞表型。体外实验显示VIP可改善OA软骨细胞增殖和功能，降低LOC727924、KPNA3和p65表达，上调miR-26a表达；体内研究亦证实，VIP改善了DMM引起的小鼠膝关节损伤。综上所述，p65-LOC727924-miR-26a/KPNA3-p65互反馈环路可调节OA软骨细胞凋亡、ECM沉积、炎症反应，是OA进展和VIP疗效发挥的关键机制。研究在加深对OA发病机制和VIP作用机制理解的同时，有望为OA的早期诊断和预防提供新的风险标识物，为OA治疗的药物开发提供指导和实验依据。项目实施期间，申请人共发表SCI论文3篇，一篇再投，培养研究生两名。