Soler Fernando, Lax Antonio, Fernández-Belda Francisco
Departamento de Bioquímica y Biología Molecular A, Universidad de Murcia, Campus de Espinardo, 30071, Murcia, Spain.
Arch Biochem Biophys. 2007 Oct 15;466(2):194-202. doi: 10.1016/j.abb.2007.06.022. Epub 2007 Jun 29.
Experimental sarcoplasmic reticulum damage induced by 3 microM thapsigargin or 1 microg/ml tunicamycin provoked viability loss of the cell population in approximately 72 h. Release of cytochrome c from mitochondria was an early event and Bax translocation to the mitochondria preceded or was simultaneous with cytochrome c release. The release of cytochrome c was not related with mitochondria depolarization or caspase activation. Irreversible stress in the sarcoplasmic reticulum, detected by the early activation of caspase 12, was functionally linked to the mitochondrial apoptotic pathway. Caspase 3 processing was blocked by cells preincubation with a selective inhibitor of either caspase 9 or caspase 8 whereas caspase 8 activation was inhibited by a selective caspase 9 inhibitor. This was consistent with the involvement of caspase 8 in a positive feedback loop leading to amplify the caspase cascade. Caspase inhibition did not protect against cell death indicating the existence of alternative caspase-independent mechanisms.
由3微摩尔毒胡萝卜素或1微克/毫升衣霉素诱导的实验性肌浆网损伤在约72小时内引发细胞群体活力丧失。细胞色素c从线粒体释放是一个早期事件，并且Bax转位至线粒体先于细胞色素c释放或与之同时发生。细胞色素c的释放与线粒体去极化或半胱天冬酶激活无关。通过半胱天冬酶12的早期激活检测到的肌浆网中的不可逆应激在功能上与线粒体凋亡途径相关联。用半胱天冬酶9或半胱天冬酶8的选择性抑制剂对细胞进行预孵育可阻断半胱天冬酶3的加工，而半胱天冬酶8的激活则被选择性半胱天冬酶9抑制剂抑制。这与半胱天冬酶8参与导致半胱天冬酶级联放大的正反馈环一致。半胱天冬酶抑制不能防止细胞死亡，表明存在其他非半胱天冬酶依赖性机制。
