The Role of gp130 Cytokines in Osteoarthritis

项目摘要 目前没有治疗方法可以阻止或减缓骨关节炎（OA）的进展。因此，我们认为， 保护关节软骨细胞免受分解代谢事件的新机制或因子的发现， 最终减缓OA进展期间的软骨降解是非常需要的。最近，细胞因子 受体样因子1（CLRF 1）和心肌营养素样细胞因子（CLC），这两种细胞因子属于IL-6或 gp130细胞因子超家族，由于其潜在的生物学活性，已成为研究热点 活动在成人生物学，退化和再生条件在广泛的器官系统。CRLF1 可以作为同二聚体或作为与CLC一起的异二聚体复合物单独发出信号。更重要的是，CRLF1 已显示同二聚体信号传导保护神经元免受氧化应激，而CRLF 1/CLC 已经显示异二聚体信号传导在各种组织成人病理学中起主要作用。先前 研究表明CRLF1由骨和软骨细胞表达。然而，我们所知甚少 关于这两种细胞因子在软骨稳态和OA病理中的作用。我们激动人心的初赛 研究结果显示，在OA的早期阶段，CRLF 1的表达增加， 炎症条件下的关节软骨细胞，刺激人关节软骨细胞中的分解代谢事件， CRLF1/CLC复合物对软骨细胞的作用，CRLF1单独的软骨保护作用支持我们的研究。 CRLF 1和CLC在软骨稳态和OA病理中起重要作用。具体地说， 我们提出，虽然异二聚体CRLF 1/CLC复合物刺激关节炎中的分解代谢事件， 软骨细胞，外源性CRLF 1，尽管存在CLC保护软骨细胞在炎症 环境为了验证我们的假设，我们提出了两个目标。在目标1中，我们将建立最佳 当CRLF1在体外保护关节软骨细胞和软骨外植体时， 在炎症条件下培养，并特别确定是否外源性CRLF1作为一种免疫调节剂。 同源二聚体，通过结合促进CRLF1/CLC/CNTFR复合物的内化和降解， SORLA，或两者都保护软骨细胞。此外，我们将确定CRLF1/CLC是否 异二聚体复合物足以在软骨细胞中诱导分解代谢事件和/或加速分解代谢 IL-1b处理的软骨细胞中的事件。使用目标1中获得的结果，我们将确定目标2 CRLF1是否可以在体内用于保护关节软骨免受关节内IL-1 β后的降解， 注射或在小鼠中的药物诱导的OA模型中，并确定CRLF1/CLC复合物是否有助于 体内的软骨退化。这项建议的顺利完成将确立两个机构的作用， 细胞因子CRLF1和CLC在关节软骨稳态和OA病理中的作用。我们预计 了解这两种细胞因子如何单独或作为复合物影响关节软骨细胞， 为治疗OA提供了新的治疗靶点。

PROJECT SUMMARY Currently there is no treatment to stop or slow down the progression of osteoarthritis (OA) available. Therefore, the discovery of novel mechanisms or factors that protect articular chondrocytes against catabolic events and ultimately slow down cartilage degradation during OA progression is highly needed. Recently, cytokine receptor-like factor 1 (CLRF1) and cardiotrophin-like cytokine (CLC), two cytokines belonging to the IL-6 or gp130 cytokine superfamily, have become the matter of intense investigations because of their potential activities in adult biology, degenerative and regenerative conditions in a wide range of organ systems. CRLF1 can signal alone as a homodimer or as a heterodimeric complex together with CLC. More importantly, CRLF1 homodimer signaling has been show to protect neurons against oxidative stress, whereas CRLF1/CLC heterodimer signaling has been shown play major roles in adult pathologies of various tissues. Previous studies have shown that CRLF1 is being expressed by bone and cartilage cells. Very little, however, is known about the role of these two cytokines in cartilage homeostasis and OA pathology. Our exciting preliminary findings showing increased expression of CRLF1 during early stages of OA, the induction of CLC expression in articular chondrocytes under inflammatory conditions, the stimulation of catabolic events in human articular chondrocytes by the CRLF1/CLC complex, and the chondro-protective effects of CRLF1 alone supports our hypothesis that CRLF1 and CLC play important roles in cartilage homeostasis and OA pathology. Specifically, we propose that while the heterodimeric CRLF1/CLC complex stimulates catabolic events in articular chondrocytes, exogenous CRLF1 despite the presence of CLC protects chondrocytes in an inflammatory environment. To test our hypothesis we are proposing two aims. In Aim 1, we will establish the optimal conditions under which exogenous CRLF1 protects articular chondrocytes and cartilage explants in vitro when cultured under inflammatory conditions, and specifically determine whether exogenous CRLF1 as a homodimer, via promoting the internalization and degradation of the CRLF1/CLC/CNTFR complex by binding to SORLA, or both protects chondrocytes. In addition, we will determine whether the CRLF1/CLC heterodimeric complex is sufficient to induce catabolic events in chondrocytes and/or accelerates catabolic events in IL-1b-treaded chondrocytes. Using the findings obtained in Aim 1, we will determine in Aim 2 whether CRLF1 can be used in vivo to protect articular cartilage against degradation after intra-articular IL-1β injection or in a surgical-induced OA model in mice, and determine whether CRLF1/CLC complex contributes to cartilage degradation in vivo. The successful completion of this proposal will establish the role of two cytokines CRLF1 and CLC in articular cartilage homeostasis and OA pathology. We expect that the understanding of how these two cytokines individually or as a complex affect articular chondrocytes will provide novel therapeutic targets for the treatment of OA.