Grigoriou Vavara, Shapiro Irving M, Cavalcanti-Adam Elisabeta A, Composto Russell J, Ducheyne Paul, Adams Christopher S
Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
J Biol Chem. 2005 Jan 21;280(3):1733-9. doi: 10.1074/jbc.M402550200. Epub 2004 Nov 1.
We tested the hypothesis that RGDS peptides regulate osteoblast survival in culture. Osteoblast-like MC3T3-E1 cells were allowed to attach to RGDS peptides that had been tethered to a silicone surface utilizing a previously described grafting technique. The RGDS-modified surface caused up-regulation of alpha(v)beta(3) integrin. We noted that there was an increase in expression of activated focal adhesion kinase and activated Akt. There was no change in the expression level of the anti-apoptotic protein Bcl-2, the pro-apoptotic protein Bad, or the inactivated form of Bad, pBad. Attachment to the RGDS-treated membrane completely abolished apoptosis induced by staurosporine, the Ca(2+).P(i) ion pair, and sodium nitroprusside. However, the surface modification did not interfere with apoptosis mediated by the free RGDS peptide or serum-free medium. When the activity of the phosphatidylinositol 3-kinase pathway was inhibited, RGDS-dependent resistance to apoptosis was eliminated. These results indicated that the binding of cells to RGDS abrogated apoptosis via the mitochondrial pathway and that the suppression of apoptosis was dependent on the activity of phosphatidylinositol 3-kinase.
我们验证了RGDS肽在培养中调节成骨细胞存活的假说。利用先前描述的嫁接技术，使成骨样MC3T3-E1细胞附着于已连接到硅酮表面的RGDS肽上。RGDS修饰的表面导致α(v)β(3)整合素上调。我们注意到，活化的粘着斑激酶和活化的Akt表达增加。抗凋亡蛋白Bcl-2、促凋亡蛋白Bad或Bad的失活形式pBad的表达水平没有变化。附着于经RGDS处理的膜上可完全消除由星形孢菌素、Ca(2 +).P(i)离子对和硝普钠诱导的细胞凋亡。然而，表面修饰并不干扰由游离RGDS肽或无血清培养基介导的细胞凋亡。当磷脂酰肌醇3-激酶途径的活性被抑制时，RGDS依赖性的抗凋亡作用被消除。这些结果表明，细胞与RGDS的结合通过线粒体途径消除了细胞凋亡，并且细胞凋亡的抑制依赖于磷脂酰肌醇3-激酶的活性。
