Wnt16在颞下颌关节骨关节炎中的时空表达及其调控软骨代谢的分子机制研究

Temporomandibular joint osteoarthritis(TMJOA) is a common disease in the oral and maxillofacial region.Research has showed recently that WNT signaling is involved in the development of TMJOA, although its underlying mechanisms is largely unknown. Recently it was shown that Wnt16 is strongly upregulated in cartilage after injury and in synovium in experimental OA. Besides,our previous studies have shown that deletion of WNT16 cause spontaneous fracture of the tibia in mice.More over, osteoblast-derived WNT16 is a key regulator of osteoclastogenesis and bone resorption. Therefore,we plan to establish a TMJOA model in mice and evaluate the temporospatial expression of WNT16 in TMJOA.Based on that, we will isolate and culture murine mandibular condylar chondrocytes in vitro. Osteoarthritis phenotype would be induced by addition of IL-1β in the medium.Cells will be treated with recombinant WNT16 to investigate its downstream signaling and mechanisms in regulating cartilage homeostasis.lastly, to explore the potential therapeutic value of targeting WNT16, RNA interference (RNAi) techniques would be applied to inhibit abnormal WNT16 signaling in vivo and in vitro. Over all,our study would shed new light on the pathophysiology of TMJOA and open new avenues for the specific prevention or treatment of TMJOA.

颞下颌关节骨关节炎(TMJOA)是口腔颌面外科的一种常见病和多发病，有研究表明WNT信号参与了TMJOA的发生，但是其作用机制仍未阐明。近年有证据显示Wnt16在创伤后的软骨内和实验性OA的关节滑膜中显著上调。本项目负责人的前期研究证实敲除小鼠Wnt16基因可导致自发性骨折，成骨细胞分泌的Wnt16是调控骨吸收的关键因子。基于以上背景，本研究拟建立小鼠TMJOA实验动物模型并检测Wnt16在TMJOA的发生过程的表达。继而在体外分离培养髁突软骨细胞并通过IL-1β诱导模拟OA环境，加入Wnt16蛋白刺激研究Wnt16在生理以及炎症情况下的下游信号转导机制以及对髁突软骨稳态的调控机制。最后通过RNAi等技术在体内和体外阻断异常表达的Wnt16信号，观察其对TMJOA的治疗作用。本研究的开展将进一步揭示TMJOA的发生机制，为其有效防治提供新思路和药物作用新靶点。

研究背景：颞下颌关节骨关节炎(TMJOA)是口腔颌面外科的一种常见病和多发病，有研究表明WNT信号参与了TMJOA的发生，但是其作用机制仍未阐明。近年有证据显示Wnt16在创伤后的软骨内和实验性OA的关节滑膜中显著上调。.目的：本研究目的是探索WNT16信号在颞下颌关节骨关节炎(TMJOA)发生、发展中的作用。.方法：本研究拟通过颞下颌关节盘部分切除术建立小鼠TMJOA实验动物模型，经组织学研究评估关节软骨确定建模成功，并应用免疫组化和原位杂交技术检测Wnt16、Lubricin 和SOX9 等信号分子在 TMJOA 发生过程中的时空表达规律。通过体外分离培养髁突软骨细胞并通过IL-1β诱导模拟OA环境，加入Wnt16蛋白刺激研究Wnt16在生理以及炎症情况下的下游信号转导机制以及对髁突软骨稳态的调控机制。.结果：WNT16在TMJOA建模早期（4周组）高表达于关节软骨，之后（8周组）表达降低。人重组WNT16蛋白显著降低IL-1β诱导的软骨基质降解标志基因（MMP1、MMP13、ADAMTS5 ）的表达水平并促进了软骨修复相关基因（Aggrecan、Type II collagen）的表达，随后在蛋白水平的免疫印迹（Western blot）检测结果也同样证明了人重组WNT16蛋白可以显著下调炎症状态下基质金属蛋白酶MMP13的表达水平。.结论：我们的数据首次证明WNT16在TMJOA的早期阶段表达上调，但是在TMJOA进展到中晚期阶段表达下调。揭示了WNT16可能通过调控lubricin的表达和维持关节软骨表层干细胞的功能来影响髁突软骨的修复和稳态。