BONE CELL DIFFERENTIATION VIA CELL ADHESION

骨骼重塑的特征是 基质蛋白调节的成骨细胞和破骨细胞 成分，细胞间的相互作用，以及各种趋化因子， 细胞因子和生长因子。在骨吸收过程中 各种骨基质成分被释放出来，这些成分有助于 通过骨祖细胞的趋化作用来协调骨重建 吸收部位与细胞的刺激、增殖和分化 将这些细胞转化为成骨细胞。整合素被认为参与了 在细胞迁移、靶标识别、细胞生长和 骨骼外组织的分化。细胞表面的作用 整合素在启动和/或调节协调的 骨重建过程中的成骨细胞成分，尽管有疾病- 定义，是至关重要的，因为有缺陷的骨重建已经观察到 成骨细胞整合素功能受损的转基因动物。这个 本项目中提出的研究旨在(I)分析 αvbeta1、alphavbeta3和alphavbeta5整合素与 成骨细胞迁移、黏附、增殖和分化；(Ii) 以确定介导这一过程的信号转导途径 整合素与骨桥蛋白、纤维连接蛋白和I型的相互作用 胶原蛋白；以及(Iii)研究成骨细胞抑制作用 分泌的细胞因子和趋化因子(IL-8、TNFα和GRO) 破骨细胞和特异性成骨因子(bFGF、BMP-2和转化生长因子-β) 整合素在成骨细胞中的表达及其在成骨细胞中的作用 调节它们对成骨细胞的作用。积累的知识 应澄清目前提出的定义以下机制的概念 控制成骨细胞的发育和活动，并激发兴趣 在开发刺激骨形成的新治疗模式方面 以成骨细胞活动缺陷或不足为特征的疾病。 所获得的信息也应该进一步加深我们对 在骨科手术中使用适当的基质蛋白 成骨细胞附着是保证正常骨形成的关键 以及植入的骨组织或多孔非骨性组织的完整性 植入物。

Skeletal remodeling is characterized by coordinated activities of osteoblasts and osteoclasts which are conditioned by matrix protein constituents, cell-cell interactions, and a variety of chemokine, cytokines, and growth factors. During the bone resorption process a variety of bone matrix constituents are released which serve to orchestrate bone remodeling via chemotaxis of osteoprogenitor cells to resorption sites and the stimulation, proliferation and differentiation of these cells into osteoblasts. Integrins have been implicated to play important roles in cell migration, target recognition, cell growth and differentiation in extraskeletal tissues. The role of cell surface integrins in either initiating and/or conditioning the coordinated osteoblastic component of the bone remodeling process, although ill- defined, is crucial since defective bone remodeling has been observed in transgenic animals with impaired integrin function in osteoblasts. The research proposed in this project is designed (i) to analyze the relationship of alphavbeta1, alphavbeta3 and alphavbeta5 integrins to osteoblast migration, adhesion, proliferation, and differentiation; (ii) to determine the signal transduction pathways which mediate the interaction between integrins and osteopontin, fibronectin, and type I collagen; and (iii) to study the effects of osteoblast inhibitory cytokines and chemokines (IL-8, TNF alpha and GRO) which are secreted by osteoclasts and specific osteogenic factors (bFGF, BMP-2, and TGF-beta) on the expression of integrins in osteoblasts and the roles of integrins in conditioning their effects on osteoblasts. The knowledge accumulated should clarify current concepts proposed to define mechanisms which control osteoblast development and activity, and also stimulate interest in developing new therapeutic modes for stimulating bone formation in disorders characterized by defective or deficient osteoblast activities. The acquired information should also further our knowledge with regard to the use of appropriate matrix proteins in orthopedic procedures where osteoblastic attachment is essential to guarantee normal bone formation and the integrity of either implanted bone tissue or porous non-osseous implants.