Mechanism of MMP gene induction in osteoarthritis

描述(由申请人提供)： 提出的研究目标是阐明基质的诱导机制。 骨关节炎患者软骨细胞中金属蛋白酶的表达 关节组织。骨关节炎(OA)表现为软骨的退化。 导致关节骨骼之间的缓冲完全丧失，从而导致 关节僵硬、肿胀和活动受限。在正常的软骨中， 每种基质金属蛋白酶的表达都受到严格的调控。然而，在OA状态下，MMPs 过度表达导致胶原和其他关节的降解 维持人体正常环境所必需的组织相关蛋白 软骨。我们假设一组转录因子负责 MMPs的表达增加，表现为较高的活性水平。 骨性关节炎软骨细胞。与这一假设一致，初步 研究表明，骨性关节炎关节组织中的软骨细胞含有 几种转录因子的水平显著升高，其中一种是 鉴定为SAF-1，一种炎症反应转录因子。 SAF-1过表达促进培养软骨细胞表达基质金属蛋白酶-1 细胞。SAF-1还与基质金属蛋白酶-9和-14基因的启动子相互作用 提示其可能在调节这些基质金属蛋白酶基因在骨性关节炎中的表达 条件。对涉及的转录因子的鉴定将提供 调节其活性以用于未来治疗的分子基础 反对美国国税局。因此，这项研究的重点是确定SAF-1在 调节基质金属蛋白酶-1、-9和-14基因的表达。这项提议的另一个目标 是为了确定参与这一过程的其他转录因子。虽然 骨性关节炎的病理很可能始于软骨的生物力学应力， 细胞因子出现在疾病的后期阶段。因此，一个类似于OA的 通过生物力学应力和细胞因子的结合来创造条件 针对这些问题，我们将对基质金属蛋白酶基因诱导机制进行研究 信号。为此，计划实现以下具体目标：1) SAF-1在软骨细胞基质金属蛋白酶-1基因诱导中的作用 骨性关节炎-软骨。定义涉及的其他响应要素和因素 骨关节炎时基质金属蛋白酶-1的表达增加。2)研究SAF-1的作用 诱导骨性关节炎软骨中基质金属蛋白酶-9基因的表达。确定其他 这一过程中涉及的监管要素和因素。3)评估 SAF-1在诱导基质金属蛋白酶-14基因表达及鉴定其他调控元件中的作用 及影响软骨细胞基质金属蛋白酶-1 4表达的因素 类骨关节炎的情况。 上述实验目标的完成将为今后的工作奠定基础 A)骨关节炎软骨细胞跨膜信号转导通路的研究 增强转录活性，以及b)评估参与的抑制物 信号通路作为潜在的治疗药物控制异常的基质金属蛋白酶 表情。

DESCRIPTION (provided by applicant): The goal proposed research is to elucidate the induction mechanism of matrix metalloproteinases (MMP) in chondrocyte cells of the osteoarthritis-affected joint tissue. Osteoarthritis (OA) is manifested by the degradation of cartilage leading to a total loss of the cushion between the bones of the joints causing stiffness, swelling and limitation of joint mobility. In normal cartilage, expression of each MMP is tightly regulated. During OA condition, however, MMPs are overexpressed resulting in the degradation of Collagen and other joint tissue-associated proteins necessary for maintaining normal environment of the cartilage. We hypothesize that a set of transcription factors, responsible for the increased expression of MMPs, is present at a higher active level in the chondrocyte cells of OA-cartilage. Consistent with this hypothesis, preliminary studies indicated that chondrocyte cells of the OA joint tissue contain a significantly higher level of several transcription factors, of which one is identified as SAF-1, an inflammation-responsive transcription factor. Over-expression of SAF-1 enhances MMP-1 expression in cultured chondrocyte cells. SAF-1 also interacts with the promoters of MMP-9 and -14 genes indicating its possible role in regulating expression of these MMP genes in OA condition. Identification of the involved transcription factors will provide a molecular basis for regulating their activity for future therapeutic efforts against OA. This research thus focuses on defining the role of SAF-1 in regulating expression of MMP-1, -9 and -14 genes. Another goal of this proposal is to identify other transcription factors involved in this process. Although pathology of OA most likely starts with biomechanical stress on the cartilage, cytokines appear at later stages of the disease. Therefore, an OA-like condition will be created by combining both biomechanical stress and cytokines and mechanisms of MMP gene induction will be studied in response to these signals. Towards this goal, the following specific aims are planned: 1) Characterize the role of SAF-1 in MMP-1 gene induction in chondrocytes of OA-cartilage. Define other responsive elements and factors involved in increasing MMP-1 expression in OA condition. 2) Investigate the role of SAF-1 in the induction of MMP-9 gene expression in OA-cartilage. Identify other regulatory elements and factors involved in this process. 3) Assess the role of SAF-1 in the induction of MMP-1 4 gene and identify other regulatory elements and factors involved in increasing MMP-1 4 expression in chondrocytes under OA-like condition. Completion of the above experimental objectives will form the basis for future investigation on: a) transmembrane signaling pathways in OA chondrocytes that enhance transcriptional activity, and b) evaluation of inhibitors of involved signaling pathway as potential therapeutic agents to control abnormal MMP expression.