The Impact of COL6A3 Mutation on Inflammatory Susceptibility in Osteoarthritis

项目摘要 骨关节炎（OA）是一种疼痛和衰弱的关节疾病，影响超过30万人在美国 一个人OA的特征在于软骨基质的进行性变性，主要是由于软骨基质的不平衡。 软骨细胞的分解代谢和合成代谢活动由遗传、化学和机械危险因素引起。电流 OA的非手术治疗仅仅依赖于控制症状，主要是由于缺乏全面的 了解导致疾病发作和发病机制的分子机制。在最近的exome 测序研究中，已确定VI型胶原蛋白α 3（COL 6A 3）中的基因突变增加 发生早发性OA的风险。COL 6A 3编码形成VI型胶原蛋白（COL 6）的蛋白质之一， 软骨细胞的细胞周围基质（PCM）的关键成分。COL 6是软骨细胞的关键介质， 通过保持PCM的结构完整性来转导化学和机械信号。很可能 COL 6A 3的突变可能通过改变PCM特性而加重OA;然而， 疾病仍然未知。在这个建议中，我们将确定COL 6A 3突变和 OA发病机制。我们假设COL 6A 3突变增加了炎症对细胞增殖的影响。 软骨细胞降解和PCM降解，导致正常软骨细胞的改变 这是对机械负荷的代谢反应，从而引发软骨退化的循环。到 完成了所提出的研究，我们已经开发了一种新的体外“OA-in-a-dish”疾病模型， 诱导多能干细胞（hiPSC）衍生的软骨细胞经基因编辑以引入COL 6A 3突变。在 具体目标1，我们将评估促炎细胞因子对生物和机械的影响。 具有和不具有COL 6A 3突变的hiPSC衍生软骨的性质。在具体目标2中，我们 确定该突变对促炎细胞因子后软骨细胞机械转导的影响 治疗该提案旨在确定早发性OA易感性增加的机械原因 由于COL 6A 3突变，可用于鉴定治疗开发的靶点。 这些研究的完成将更好地确定机械，遗传和生化因素 一致行动导致OA。

PROJECT SUMMARY Osteoarthritis (OA) is a painful and debilitating joint disease affecting over 30 million people in the United States alone. OA is characterized by the progressive degeneration of cartilage matrix primarily due to an imbalance of chondrocyte catabolic and anabolic activities arising from genetic, chemical, and mechanical risk factors. Current non-surgical treatments for OA rely simply on managing symptoms primarily owing to a lack of a full understanding of the molecular mechanisms leading to disease onset and pathogenesis. In recent exome sequencing studies, genetic mutation in collagen type VI alpha three (COL6A3) has been identified to increase risk of developing early-onset OA. COL6A3 encodes for one of the proteins that forms collagen type VI (COL6), a critical component of the chondrocyte’s pericellular matrix (PCM). COL6 is a key mediator of the chondrocyte’s transduction of chemical and mechanical cues by maintaining the structural integrity of the PCM. It is likely that mutation in COL6A3 may exacerbate OA by altering PCM properties; however, the mechanisms leading to disease remain unknown. In this proposal, we will determine the molecular link between COL6A3 mutation and OA etiopathogenesis. We hypothesize that COL6A3 mutation increases the effect of inflammation on chondrocyte catabolism and PCM degradation, leading to alterations in the normal chondrocyte metabolic response to mechanical loading thereby initiating a cycle of cartilage degeneration. To complete the proposed studies, we have developed a novel in vitro “OA-in-a-dish” disease model using human induced pluripotent stem cell (hiPSC)-derived chondrocytes gene-edited to introduce the COL6A3 mutation. In specific aim 1, we will assess the effects of proinflammatory cytokines on the biological and mechanical properties of hiPSC-derived cartilage with and without the COL6A3 mutation. Then, in specific aim 2, we will determine the effect of this mutation on chondrocyte mechanotransduction following proinflammatory cytokine treatment. This proposal aims to determine a mechanistic cause for increased predisposition to early on-set OA due to mutation in COL6A3, that can be used for the identification of targets for therapeutic development. Completion of these studies will better define the mechanisms that mechanical, genetic, and biochemical factors act in concert and lead to OA.