强啡肽/阿片受体kappa信号对创伤后的炎症反应以及骨关节炎发生的分子调控机制研究

Osteoarthritis also called degenerative arthritis, is a type of joint disease that results from breakdown of joint cartilage and underlying bone. The most common symptoms are joint pain and stiffness. Causes include previous joint injury, abnormal joint or limb development, and inherited factors, among which injury caused inflammation plays an important role in the onset and progress of osteoarthritis. Our previous study showed that Pdyn (the gene encoding dynorphin) and Opioid receptor kappa (KOR) are expressed in synovial and cartilage tissue during human development. The expressions of Pdyn and KOR are also found in adult human joint tissues. In murine model of osteoarthritis, expression of KOR increased significantly after one week of surgery. Our results also indicated that activation of KOR by chemical agonist inhibited the expression of catabolic genes in cultured chondrocytes, as well as increased glycosaminoglycans (GAG) synthesis by chondrocytes. In this study, we plan to use injury caused osteoarthritic model to study the influence of Dyn/KOR signaling pathway on the injury-caused inflammation and pathogenesis of osteoarthritis. Transgenic mice with KOR knockout will be used for surgery. Micro-CT will be performed to evaluate sub-chondral bone. Histological examination will be performed to evaluate the degradation of cartilage tissue. We propose to use in vitro culture model of rabbit articular chondrocytes to investigate the molecular mechanism of KOR regulated anabolic and catabolic effects. RNA interference technique will be used to knock down the expression of Oprk1. A clinical samples from patients who plan to undergo total knee or hip joint replacement will be collected. Osteoarthritic cartilage will be chopped into uniform sizes with biopsy punch, and cultured as explants. Non-steroidal anti-inflammatory drugs and KOR agonist will be used to treat cartilage explants. We will test if Opioid analgesics is superior to other drugs in reducing the degeneration of cartilage tissue in an osteoarthritic environment.

骨关节炎是临床上常见的慢性病。创伤后炎症反应是诱发骨关节炎的重要因素。研究相关信号通路如何调控炎症反应，对缓解关节疼痛，预防和治疗骨关节炎，具有重大意义。我们的前期研究证实，κ阿片受体及配体强啡肽广泛表达于软骨及滑膜发育的各个时期。小鼠膝关节创伤后κ受体表达上调。激活κ受体可抑制TNF-α诱发的分解代谢，还可促进细胞合成软骨基质。本研究拟采用创伤引起的膝盖骨关节炎模型，用化学激动剂激活κ受体或者用转基因技术敲除κ受体基因，从正反两方面，探索κ阿片受体信号对骨关节炎发生过程的影响。并用RNA-seq技术筛选κ受体下游关键分子。同时，还将采用软骨细胞体外培养模型，深入研究κ阿片受体如何通过降低PKA的活性，抑制NFκB信号通路诱发的分解代谢作用，揭示κ受体信号抑制软骨基质降解的分子机制。本项目完成后有望阐明强啡肽/κ阿片受体信号对骨关节炎发生的分子调控机制，为骨关节炎的新药开发提供理论依据。