Integrin α2β1 plays a critical role in osteoblast response to micron-scale surface structure and surface energy of titanium substrates
Integrin α2β1 plays a critical role in osteoblast response to micron-scale surface structure and surface energy of titanium substrates
复制标题
DOI：
10.1073/pnas.0805420105
复制
发表时间：
2008-10-14
影响因子：
11.1
通讯作者：
Schwartz, Z.
中科院分区：
文献类型：
--
作者：
Olivares-Navarrete, R.;Raz, P.;Schwartz, Z.
改善骨对生物材料反应的努力集中在结合α 5 β 1整合素的配体上。然而，α 5 β 1抗体可减少成骨细胞增殖，但不影响细胞在钛（Ti）上生长时的分化。β 1沉默阻断了Ti微地形的分化刺激，表明其他β 1伙伴也很重要。使用稳定α 2沉默的MG63人成骨细胞样细胞来检测α 2 β 1是否特异性介导成骨细胞对钛表面微米级结构和能量的反应。WT和α 2沉默的MG63细胞在组织培养聚苯乙烯（TCPS）和钛盘上培养，表面微形貌不同：机械预处理（PT）表面[平均峰谷粗糙度(R-a) < 0.02 μ m]，喷砂和酸蚀的PT表面（SLA; R-a = 4 μ m），表面能高的SLA （modSLA）。碱性磷酸酶（ALP）、α 2和β 1 mRNA，但α 5、α v、β 3、i型胶原或骨钙素在第6天的SLA和modSLA中升高。α 2在TCPS和PT组第8天升高，但在SLA和modSLA组保持不变。α 2-siRNA细胞中α 2- mrna减少70%，而α 5-mRNA和蛋白未受影响。α 2敲除阻断了在SLA和modSLA上生长的MG63细胞的表面依赖性β 1和骨钙素的增加，以及细胞数量的减少和ALP和局部因子的增加[例如，前列腺素E-2、骨保护素、潜伏和活性tgf - β 1，以及1 α，25(OH)(2)D-3对这些参数的刺激作用]。这一发现表明α 2 β 1信号是由钛微观结构和表面能引起的成骨细胞分化所必需的，这表明基于细胞在TCPS上行为的结论不能预测在其他底物上的行为或相关机制。
Efforts to improve bone response to biomaterials have focused on ligands that bind alpha 5 beta 1 integrins. However, antibodies to alpha 5 beta 1 reduce osteoblast proliferation but do not affect differentiation when cells are grown on titanium (Ti). beta 1-silencing blocks the differentiation stimulus of Ti microtopography, suggesting that other beta 1 partners are important. Stably alpha 2-silenced MG63 human osteoblast-like cells were used to test whether alpha 2 beta 1 specifically mediates osteoblast response to Ti surface micron-scale structure and energy. WT and alpha 2-silenced MG63 cells were cultured on tissue culture polystyrene (TCPS) and Ti disks with different surface microtopographies: machined pretreatment (PT) surfaces [mean peak to valley roughness (R-a) < 0.02 mu m], PT surfaces that were grit-blasted and acid-etched (SLA; R-a = 4 mu m), and SLA with high surface energy (modSLA). Alkaline phosphatase (ALP), alpha 2 and beta 1 mRNA, but not alpha 5, alpha v, beta 3, type-I collagen, or osteocalcin, increased on SLA and modSLA at 6 days. alpha 2 increased at 8 days on TCPS and PT, but remained unchanged on SLA and modSLA. alpha 2-protein was reduced 70% in alpha 2-siRNA cells, whereas alpha 5-mRNA and protein were unaffected. alpha 2-knockdown blocked surface-dependent increases in beta 1 and osteocalcin and decreases in cell number and increases in ALP and local factors typical of MG63 cells grown on SLA and modSLA [e.g., prostaglandin E-2, osteoprotegerin, latent and active TGF-beta 1, and stimulatory effects of 1 alpha,25(OH)(2)D-3 on these parameters]. This finding indicates that alpha 2 beta 1 signaling is required for osteoblastic differentiation caused by Ti microstructure and surface energy, suggesting that conclusions based on cell behavior on TCPS are not predictive of behavior on other substrates or the mechanisms involved.