Release of cytochrome c and activation of pro-caspase-9 following lysosomal photodamage involves bid cleavage
Release of cytochrome c and activation of pro-caspase-9 following lysosomal photodamage involves bid cleavage
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DOI：
10.1038/sj.cdd.4401048
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发表时间：
2002-09-01
影响因子：
12.4
通讯作者：
Kessel, D
中科院分区：
文献类型：
--
作者：
Reiners, JJ;Caruso, JA;Kessel, D
采用溶酶体敏化剂的光动力疗法（PDT）方案通过在线粒体膜电位损失（DeltaPsi（m））之前引起细胞色素c释放的机制诱导细胞凋亡。本研究旨在确定溶酶体光损伤如何启动小鼠肝癌1c 1c 7细胞中的细胞凋亡。荧光显微镜显示光敏剂N-乙酰二氢卟酚e6（NPe 6）定位于溶酶体。预装载NPe 6的培养物的照射诱导溶酶体的快速破坏，以及随后Bid、前半胱天冬酶-9和-3的裂解/活化。caspase-8原未被激活。细胞色素c的释放发生在大约Bid裂解的时间，并且在Δ Psi（m）的损失之前。纯化的溶酶体的提取物催化在体外裂解的胞质Bid，但没有前半胱天冬酶-3激活。组织蛋白酶B、L和D活性的药理学抑制不抑制Bid裂解或前半胱天冬酶-9和-3活化。这些研究表明，光损伤的溶酶体通过释放激活Bid的蛋白酶触发线粒体凋亡途径。
Photodynamic therapy (PDT) protocols employing lysosomal sensitizers induce apoptosis via a mechanism that causes cytochrome c release prior to loss of mitochondrial membrane potential (DeltaPsi(m)). The current study was designed to determine how lysosomal photodamage initiates mitochondrial-mediated apoptosis in murine hepatoma 1c1c7 cells. Fluorescence microscopy demonstrated that the photosensitizer N-aspartyl chlorin e6 (NPe6) localized to the lysosomes. Irradiation of cultures preloaded with NPe6 induced the rapid destruction of lysosomes, and subsequent cleavage/activation of Bid, pro-caspases-9 and -3. Pro-caspase-8 was not activated. Release of cytochrome c occurred at about the time of Bid cleavage and preceded the loss of DeltaPsi(m). Extracts of purified lysosomes catalyzed the in vitro cleavage of cytosolic Bid, but not pro-caspase-3 activation. Pharmacological inhibition of cathepsin B, L and D activities did not suppress Bid cleavage or pro-caspases-9 and -3 activation. These studies demonstrate that photodamaged lysosomes trigger the mitochondrial apoptotic pathway by releasing proteases that activate Bid.