Cytosolic heat shock protein 60, apoptosis, and myocardial injury
Cytosolic heat shock protein 60, apoptosis, and myocardial injury
复制标题
DOI：
10.1161/01.cir.0000019403.35847.23
复制
发表时间：
2002-06-18
期刊：
影响因子：
37.8
通讯作者：
Knowlton, AA
中科院分区：
文献类型：
--
作者：
Kirchhoff, SR;Gupta, S;Knowlton, AA
热休克蛋白（HSPs）以其“保护”天然大分子的结构和功能的能力而闻名，特别是当它们穿越膜时。考虑到关键线粒体蛋白在细胞凋亡中的作用以及已知的HSP27和HSP72的抗凋亡作用，我们假设HSP60主要是一种线粒体蛋白，也具有抗凋亡作用。方法和结果：为了验证这一假设，我们使用反义硫代寡核苷酸使心肌细胞中HSP60水平降低50%，心肌细胞是一种具有丰富线粒体的细胞类型。诱导的HSP60的降低可促进细胞凋亡，表现为细胞色素c的释放、caspase 3的激活和DNA断裂的诱导。反义处理与bax的增加和bcl-2的减少有关，这是由于bax的合成增加和bcl-2的降解。对照寡核苷酸对这些测量没有影响。我们进一步证明，在体外，胞质HSP60与bax和bak形成大分子复合物，表明与HSP60形成复合物可能阻断bax和bak在体内影响细胞凋亡的能力。最后，我们发现，随着细胞质（非线粒体）HSP60的降低，出现了一小部分未结合的bax，而与线粒体和细胞膜相关的bax的数量增加。结论：这些结果支持细胞质HSP60的关键抗凋亡作用。据我们所知，这是首次报道HSP60与bax和/或bak的相互作用调节细胞凋亡。
Background-Heat shock proteins (HSPs) are well known for their ability to "protect" the structure and function of native macromolecules, particularly as they traffic across membranes. Considering the role of key mitochondrial proteins in apoptosis and the known antiapoptotic effects of HSP27 and HSP72, we postulated that HSP60, primarily a mitochondrial protein, also exerts an antiapoptotic effect.Methods and Results-To test this hypothesis, we used an antisense phosphorothioate oligonucleotide to effect a 50% reduction in the levels of HSP60 in cardiac myocytes, a cell type that has abundant mitochondria. The induced decrease in HSP60 precipitated apoptosis, as manifested by the release of cytochrome c, activation of caspase 3, and induction of DNA fragmentation. Antisense treatment was associated with an increase in bax and a decrease in bcl-2 secondary to increased synthesis of bax and degradation of bcl-2. A control oligonucleotide had no effect on these measurements. We further demonstrated that cytosolic HSP60 forms a macromolecular complex with bax and bak in vitro suggesting that complex formation with HSP60 may block the ability of bax and bak to effect apoptosis in vivo. Lastly, we show that as cytosolic (nonmitochondrial) HSP60 decreases, a small unbound fraction of bax appears and that the amount of bax associated with the mitochondria and cell membranes increases.Conclusions-These results support a key antiapoptotic role for cytosolic HSP60. To our knowledge, this is the first report suggesting that interactions of HSP60 with bax and/or bak regulate apoptosis.