INTEGRIN-EXTRACELLULAR MATRIX INTERACTIONS AND OSTEOBLAST DIFFERENTIATION

整合素-细胞外基质相互作用和成骨细胞分化

• 批准号: 6104827
• 负责人: CAROLINE H DAMSKY
• 金额: $ 9.14万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-12-01 至 1999-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6104827
• 关键词: affinity chromatography; biological signal transduction; cell cell interaction; cell differentiation; extracellular matrix; fibronectins; gel electrophoresis; gene expression; hamsters; integrins; laboratory rabbit; ligands; monoclonal antibody; osteoblasts; recombinant proteins; tissue inhibitor of metalloproteinases; transforming growth factors

The overall goal of this proposal is to understand the role of signals resulting from cell-extracellular matrix (ECM) interactions in the differentiation of osteoblasts. Considerable data support the idea that the osteoblast lineage is derived from a multipotential mesenchymal stem cell that also has the capacity to form other connective tissue cell types. Several multipotential cell lines have recently been established that can differentiate in vitro into cells with osteoblastic characteristics, given the appropriate stimulus. The recently characterized rat C26 osteoblastic cell line expresses very low levels of early markers of osteoblastic differentiation, such as alkaline phosphatase, and forms myotubes at confluence. However, C26 cells can be stimulated to exhibit a differentiated osteoblastic phenotype either by culture in type I collagen gels or exposure to BMP-2, a TGF-beta-like growth factor. Based on these data, the hypothesis to be tested is the specific cell-ECM interactions, mediated by members of the integrin family of ECM receptors, play a critical role in promoting osteoblastic differentiation. One mechanism by which this might occur predicts that ECM ligands, via their integrin receptors, regulate expression of TGF- beta-like growth factors. Alternatively integrin-ECM interactions and TGF-beta-like growth factors might play a cooperative or synergistic role in osteoblastic differentiation. At present, little is known about the identities of specific cell surface ECM receptors expressed at critical stages in the differentiation of OB, or about their targets in the matrix. In addition, the mechanisms by which such cell-ECM interactions might signal mesenchymal precursors to differentiate along the osteoblastic pathway and to maintain a stable osteoblastic phenotype are poorly understood. This proposal is designed to increase understanding of these important areas. Specifically, we will: 1) Characterize the osteogenic response of C26 cells to selected ECM constituents, with the goal of optimizing ECM-induced osteoblastic differentiation of C26 cells; 2) test the hypothesis that interactions between ECM and specific integrin receptors are required for osteoblastic differentiation; 3) determine whether particular integrin-ECM interactions regulate expression of TGF-beta-like growth factors during osteoblastic differentiation; 4) determine whether selected members of the TGF-beta superfamily and ECM constituents act synergistically to promote osteoblastic differentiation of C26 cells; 5) test the hypothesis that accumulation and stabilization of the characteristic osteoblastic ECM involves regulation of matrix-metalloproteinases and their inhibitors by specific integrin-ECM interactions. Greater understanding of the mechanisms by which osteoblast differentiation is regulated should lead to development of more effective materials for the restoration of skeletal deficiencies resulting from aging, arthritis, surgery, trauma and congenital defects.

本提案的总体目标是了解信号的作用 由于细胞-细胞外基质（ECM）相互作用， 成骨细胞的分化。 大量数据支持这样一种观点， 成骨细胞谱系来源于多潜能间充质干细胞 也有能力形成其他结缔组织细胞的细胞 类型 最近建立了几种多能细胞系 可以在体外分化成成骨细胞 #21453;的特点，给予适当的刺激。 最近 特征性大鼠C26成骨细胞系表达非常低的水平 成骨细胞分化的早期标志物，如碱性 磷酸酶，并在汇合时形成肌管。 C26细胞可以 被刺激以表现出分化的成骨细胞表型， 通过在I型胶原凝胶中培养或暴露于BMP-2，TGF-β样 生长因子 基于这些数据，待检验的假设是 由整合素成员介导的特异性细胞-ECM相互作用 ECM受体家族，在促进成骨细胞生长中起关键作用。 分化 可能发生这种情况的一种机制预测， ECM配体通过其整合素受体调节TGF-β 1的表达。 β-样生长因子 或者，整合素-ECM相互作用和 TGF-β样生长因子可能起协同或协同作用 成骨细胞分化。 目前，人们对这一问题知之甚少。 特异性细胞表面ECM受体的特性在关键表达 在OB的分化阶段，或关于他们的目标， 矩阵 此外，这种细胞-ECM相互作用的机制 可能是间充质前体分化的信号，沿着 成骨细胞途径和维持稳定的成骨细胞表型是 不太了解。 这项建议旨在增进了解 这些重要领域。 具体而言，我们将：1）描述 C26细胞对所选ECM成分的成骨反应， 优化ECM诱导的C26细胞成骨分化的目标; 2)检验ECM和特定的 成骨细胞分化需要整合素受体; 3） 确定特定的整合素-ECM相互作用是否调节 成骨细胞生长过程中TGF-β样生长因子的表达 4）确定所选择的TGF-β成员是否与细胞分化有关; 超家族和ECM成分协同作用以促进 C26细胞的成骨细胞分化; 5）检验假设， 特征性成骨细胞ECM的积累和稳定 涉及基质金属蛋白酶及其抑制剂的调节， 特异性整合素-ECM相互作用。 人更好地了解各项 成骨细胞分化的调节机制应该导致 开发更有效的材料， 由于老化、关节炎、手术、创伤导致的骨骼缺陷 和先天性缺陷。