Inhibition of oligodendrocyte apoptosis by sublytic C5b-9 is associated with enhanced synthesis of bcl-2 and mediated by inhibition of caspase-3 activation.
Inhibition of oligodendrocyte apoptosis by sublytic C5b-9 is associated with enhanced synthesis of bcl-2 and mediated by inhibition of caspase-3 activation.
复制标题
DOI：
10.4049/jimmunol.163.11.6132
复制
发表时间：
1999-12
影响因子：
4.4
通讯作者：
L. Soane;H. Rus;F. Niculescu;Moon L. Shin
中科院分区：
文献类型：
--
作者：
L. Soane;H. Rus;F. Niculescu;Moon L. Shin
我们之前已经在体外证明，补体的膜攻击复合体亚溶性C5b-9的产生诱导少突胶质细胞进入细胞周期并减少凋亡细胞的死亡。本研究研究了参与少突胶质细胞祖细胞和少突胶质细胞凋亡的细胞因子，以及C5b-9对凋亡过程的抑制作用。从新生大鼠脑中分离的少突胶质细胞祖细胞经mAb A2B5鉴定，在无血清培养基中分化为少突胶质细胞。分化与凋亡细胞死亡同时发生，与bcl-2 mRNA的快速丢失和caspase-3 mRNA的表达增加有关。分化细胞中caspase-3的激活可以通过caspase-3前酶的17和12 kda片段的产生以及caspase-3特异性底物聚（adp -核糖）聚合酶的裂解来证明。caspase-3抑制剂DEVD-CHO以剂量依赖的方式抑制与分化相关的细胞死亡。亚裂解C5b-9的组装抑制了caspase-3的激活。此外，C5b-9显著增加了少突胶质细胞中BCL-2蛋白的合成。tnf - α诱导的少突胶质细胞凋亡也被C5b-9抑制。这些结果表明，在影响中枢神经系统的炎症和免疫介导的脱髓鞘过程中，C5b-9上调BCL-2蛋白和抑制caspase-3活化可能是C5b-9在体外和体内提高少突胶质细胞存活率的潜在机制。
We have previously shown that generation of sublytic C5b-9, the membrane attack complex of complement, induces oligodendrocytes to enter cell cycle and reduces apoptotic cell death in vitro. In the present study, the cellular factors involved in apoptosis of oligodendrocyte progenitor cells and oligodendrocytes, and the inhibitory effect of C5b-9 on apoptotic process were investigated. Oligodendrocyte progenitor cells identified by mAb A2B5 that were isolated from neonatal rat brains were differentiated into oligodendrocytes in serum-free defined medium. The differentiation, which occurs simultaneously with apoptotic cell death, was associated with a rapid loss of bcl-2 mRNA and increased expression of caspase-3 mRNA. Activation of caspase-3 in differentiating cells was demonstrated by the generation of 17- and 12-kDa fragments of caspase-3 proenzyme and by cleavage of poly(ADP-ribose) polymerase, a specific caspase-3 substrate. Cell death associated with differentiation was inhibited by the caspase-3 inhibitor DEVD-CHO in a dose-dependent manner. Assembly of sublytic C5b-9 resulted in inhibition of caspase-3 activation. In addition, synthesis of BCL-2 protein in oligodendrocytes was significantly increased by C5b-9. The TNF-alpha-induced apoptosis of oligodendrocytes was also inhibited by C5b-9. These results indicate that up-regulation of BCL-2 protein and inhibition of caspase-3 activation are potential mechanisms by which C5b-9 increases survival of oligodendrocyte in vitro and possibly in vivo during inflammation and immune-mediated demyelination affecting the CNS.