The mechanism of mitochondrial membrane potential retention following release of cytochrome c in apoptotic GT1-7 neural cells
The mechanism of mitochondrial membrane potential retention following release of cytochrome c in apoptotic GT1-7 neural cells
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DOI：
10.1038/sj.cdd.4400916
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发表时间：
2001-10-01
影响因子：
12.4
通讯作者：
Nicholls, DG
中科院分区：
文献类型：
--
作者：
Rego, AC;Vesce, S;Nicholls, DG
研究了星形孢菌素(STS)诱导BCL-2和GT1-7Puro细胞凋亡过程中线粒体膜电位(Delta Psi(M))、呼吸作用与细胞色素c(Cytc)释放的关系。Bcl2抑制线粒体细胞色素c的释放和细胞凋亡。在GT1-7Puro细胞中发现了三种不同的细胞对STS的反应：(I)Delta Psi(M)和cytc都没有受到显著影响；(Ii)Delta Psi(M)的减少伴随着cytc的完全释放；或(Iii)Cytc的释放独立于Delta Psi(M)的丢失而发生。通过呼吸监测，在有寡霉素存在的情况下，STS使Puro细胞的内源性线粒体内膜质子泄漏增加了92%，而bcl2细胞仅增加了23%。在有原载体存在的情况下，STS使Puro细胞的呼吸量下降了31%，bcl2细胞的呼吸量下降了20%。在没有STS的情况下，寡霉素使Puro和bcl2转基因细胞内的线粒体超极化，表明这些细胞器是ATP的净生成器。然而，在STS作用15h后，寡霉素迅速瓦解了Puro细胞中残留的线粒体极化，表明ATP合成酶逆转维持了Delta Psi(M)。相比之下，BCL-2细胞维持Delta Psi(M)，直到加入原载体。这些结果表明，在STS处理的GT1-7细胞中，Cytc释放后Delta Psi(M)的维持可能是ATP合成酶逆转和胞浆ATP水解的结果。
The relationship is investigated between mitochondrial membrane potential (Delta Psi (M)), respiration and cytochrome c (cyt c) release in single neural bcl-2 transfected cells ( GT1-7bcl-2) or GT1-7puro cells during apoptosis induced by staurosporine (STS). Bcl-2 inhibited the mitochondrial release of cyt c and apoptosis. Three different cell responses to STS were identified in GT1-7puro cells: (i) neither Delta Psi (M) nor cyt c were significantly affected; (ii) a decrease in Delta Psi (M) was accompanied by a complete release of cyt c; or (iii) cyt c release occurred independently of a loss of Delta Psi (M). The endogenous inner membrane proton leak of the in situ mitochondria, monitored by respiration in the presence of oligomycin, was increased by STS by 92% in puro cells, but by only 23% in bcl-2 cells. STS decreased respiratory capacity, in the presence of protonophore, by 31% in puro cells and by 20% in bcl-2 cells. In the absence of STS, oligomycin hyperpolarized mitochondria within both puro and bcl-2-transfected cells, indicating that the organelles were net generators of ATP. However after 15 h exposure to STS oligomycin rapidly collapsed residual mitochondrial polarization in the puro cells, indicating that Delta Psi (M) had been maintained by ATP synthase reversal. bcl-2 cells in contrast, maintained Delta Psi (M) until protonophore was added. These results indicate that the maintenance of Delta Psi (M) following release of cyt c may be a consequence of ATP synthase reversal and cytoplasmic ATP hydrolysis in STS-treated GT1-7 cells.