Enhanced expression of the osteoblastic phenotype on substrates that modulate fibronectin conformation and integrin receptor binding
Enhanced expression of the osteoblastic phenotype on substrates that modulate fibronectin conformation and integrin receptor binding
复制标题
DOI：
10.1016/s0142-9612(01)00387-8
复制
发表时间：
2002-06-01
期刊：
影响因子：
14
通讯作者：
García, AJ
中科院分区：
文献类型：
--
作者：
Stephansson, SN;Byers, BA;García, AJ
整合素代表细胞-细胞外基质相互作用的主要机制并控制细胞形态、增殖和分化。我们之前已经表明，吸附纤连蛋白 (Fn) 构象的底物依赖性调节会改变 α(5)β(1) 整联蛋白与 Fn 的结合，并指导 C2Cl2 成肌细胞增殖和分化 (Mol. Biol. Cell 10 (1999) 785)。这些实验中使用的模型基质是细菌学（未经处理）聚苯乙烯 (B)、组织培养聚苯乙烯 (T) 和 I 型胶原蛋白涂层 T (C)。在本研究中，我们检查了 MC3T3-E1 成骨细胞样细胞在 Fn 包被的 B、T 和 C 基质上的分化。免疫荧光染色揭示了整合素α(5)β(1)结合和聚集成粘着斑的底物依赖性差异(C > T > B)，与我们之前的整合素结合分析一致。碱性磷酸酶活性和基质矿化显示出底物依赖性差异（C > T > B，p < 0.05）。碱性磷酸酶、骨钙素和骨唾液蛋白基因表达也观察到类似的趋势。使用针对 Fn 的抗体进行的封闭实验完全抑制了 Fn 包被的 C 上的基质矿化，表明 Fn 对于成骨细胞表型油（这种细胞外基质成分）的表达至关重要。成骨细胞分化中这些底物依赖性差异与 α(5)β(1) 结合的差异相关，表明这些差异源于整合素-基质相互作用的底物调节。细胞功能的底物依赖性调节可以提供一种通用机制来控制许多生物医学应用中的细胞反应。 (C) 2002 Elsevier Science Ltd. 保留所有权利。
Integrins represent the primary mechanism of cell-extracellular matrix interactions and control cell morphology, proliferation, and differentiation. We have previously shown that substrate-dependent modulation of adsorbed fibronectin (Fn) conformation alters alpha(5)beta(1) integrin binding to Fn and directs C2Cl2 myoblast proliferation and differentiation (Mol. Biol. Cell 10 ( 1999) 785). The model substrates used in these experiments were bacteriological (untreated) polystyrene (B), tissue culture polystyrene (T), and type-I collagen-coated T (C). In the present study, we examined MC3T3-E1 osteoblast-like cell differentiation on Fn-coated B, T, and C substrates. Immunofluorescence staining revealed substrate-dependent differences in integrin alpha(5)beta(1) binding and clustering into focal adhesions (C > T > B), consistent with our previous integrin binding analysis. Alkaline phosphatase activity and matrix mineralization showed substrate-dependent differences (C > T > B, p < 0.05). Similar trends were observed for alkaline phosphatase, osteocalcin, and bone sialoprotein gene expression. Blocking experiments with antibodies directed against Fn completely inhibited matrix mineralization on Fn-coated C, indicating that Fn is critical to expression of the osteoblastic phenotype oil this extracellular matrix component. These substrate-dependent differences in osteoblast differentiation correlated with differences in α(5)β(1) binding, suggesting that these differences arise from substrate modulation of integrin-matrix interactions. Substrate-dependent modulation of cell function may provide a versatile mechanism to control cell responses in numerous biomedical applications. (C) 2002 Elsevier Science Ltd. All rights reserved.