Regulation of chondrocytes by extracellular matrix protein.

抽象的。F-响应蛋白是属于TSR亚群的蛋白质家族中的一员 (凝血酶敏感蛋白)I类分子。我们已经发现，F-Respondin的表达显著 在骨关节炎软骨和啮齿动物半月板切除模型的骨关节炎中增加。初步研究 提示F-Spinin对人软骨细胞代谢有显著影响，在软骨细胞中也有表达。 胚胎生长板的肥大区域，在那里它调节矿化和 软骨内骨形成。这一建议旨在表征F-响应素的功能效应， 这对办公自动化的发展具有重大的、以前未被认识到的影响。我们将测试两个 中心假说：1)F-响应蛋白通过未知的途径调节胶原降解，包括 转化生长因子-β活化及基质金属蛋白酶和2)F-响应素诱导关节肥大分化 软骨细胞，在矿化和软骨内骨的调节中起重要作用 队形。旨在检验这些假设的具体目标如下：在具体目标1中，我们将 探讨F-响应蛋白对人体肥大和矿化活动的调节作用 关节软骨细胞体外培养模型的建立。软骨标本将进行组织学检查，以 探讨F-响应蛋白与骨性关节炎其他特征性肥大/骨化标志物之间的联系 软骨细胞。在特定的目标2中，我们将研究F-响应蛋白介导的分子机制(S) 骨性关节炎软骨中的胶原降解。外植体或细胞培养将用于a)鉴定F-1诱导的MMPs。 并检测它们在F-Spinin介导的胶原降解中的作用b)确定转化生长因子-β的作用 在调节F-响应素功能和c)比较全长F-响应素分子的功能活性 相对于它的蛋白质分解片段。在特定的目标3中，我们将识别和描述相互作用 F-响应素蛋白。A)研究F-响应蛋白与潜伏期相关肽(LAP)的相互作用 和b)利用酵母2杂交和蛋白质组学技术鉴定新的F-。 Spindin结合蛋白(蛋白酶、受体、基质分子)，可调节其在关节中的活性 软骨。在特定的AIM 4中，我们将研究F-Spinin在兔软骨中的表达和功能。 活着。我们将研究在活体软骨中F-Spinin的表达I)在软骨内骨发育过程中 和ii)在小鼠半月板切除模型中。我们将产生一个F-spaindin基因敲除小鼠 软骨内骨发育和骨性关节炎过程中软骨表型的变化 进步。了解F-响应蛋白对软骨细胞功能的调节可能导致新的 骨关节炎的软骨修复和疾病修正治疗的策略。

Abstract. F-spondin is a member of a family of proteins that collectively belong to a subgroup of TSR (thrombospondin) type I class molecules. We have discovered that F-spondin expression is significantly increased in osteoarthritic cartilage as well as in rodent meniscectomy models of OA. Preliminary studies indicate that F-spondin has significant effects on human chondrocyte metabolism and is also expressed in the hypertrophic regions of embryonic growth plates where it acts to regulate mineralization and endochondral bone formation. This proposal is designed to characterize the functional effects of F-spondin, which have major and previously unrecognized implications for the progression of OA. We will test two central hypotheses: 1) F-spondin modulates collagen degradation via unrecognized pathways that include activation of TGF-¿ and induction of MMPs and 2) F-spondin induces hypertrophic differentiation of articular chondrocytes and plays an essential role in the regulation of mineralization and endochondral bone formation. The specific aims designed to test these hypotheses are as follows: In SPECIFIC AIM 1 we will investigate the effects of F-spondin on the regulation of hypertrophy and mineralizing activity in human articular chondrocytes in vitro culture models. Cartilage specimens will be examined histologically to investigate the link between F-spondin and other characteristic hypertrophic/ossification markers of OA chondrocytes. In SPECIFIC AIM 2 we will investigate the molecular mechanism(s) of F-spondin-mediated collagen degradation in OA cartilage. Explant or cell cultures will be used to a) identify MMPs induced by F- spondin and examine their role in F-spondin-mediated collagen degradation b) establish the role of TGF-¿ in modulation of F-spondin functions and c) compare functional activity of the full length F-spondin molecule relative to its proteolytic fragments. In SPECIFIC AIM 3 we will identify and characterize the interacting proteins of F-spondin. a) investigate the interaction of F-spondin with the Latency-associated peptide (LAP) of the latent TGF-¿ complex and b) utilize yeast 2 hybrid and proteomic technologies to identify novel F- spondin binding proteins (proteases, receptors, matrix molecules) that may regulate its activity in articular cartilage. In SPECIFIC AIM 4 we will investigate the expression and function of F-spondin in cartilage in vivo. We will investigate F-spondin expression in cartilage in vivo i) during endochondral bone development and ii) in the mouse meniscectomy model of OA. We will generate an F-spondin knockout mouse and characterize the changes in cartilage phenotype during endochondral bone development and OA disease progression. Understanding the regulation of chondrocyte functions by F-spondin could lead to novel strategies for cartilage repair and disease modifying treatments for osteoarthritis.