Heat shock protein 60 or 70 activates nitric-oxide synthase (NOS) I- and inhibits NOSII-associated signaling and depresses the mitochondrial apoptotic cascade during brain stem death
Heat shock protein 60 or 70 activates nitric-oxide synthase (NOS) I- and inhibits NOSII-associated signaling and depresses the mitochondrial apoptotic cascade during brain stem death
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DOI：
10.1074/jbc.m603394200
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发表时间：
2007-02-16
影响因子：
4.8
通讯作者：
Chang, Alice Y. W.
中科院分区：
文献类型：
--
作者：
Chan, Julie Y. H.;Cheng, Hsiao-Lei;Chang, Alice Y. W.
脑干死亡的细胞和分子基础仍然是一个谜。作为反映脑干死亡进程的“生死”信号的起源，延髓头端腹外侧（RVLM）是机械描述这种现象的合适神经基质。在这里，我们评估了热休克蛋白 (HSP) 在脑干死亡过程中 RVLM 中发挥神经保护作用的假设，并使用临床相关的动物模型（使用有机磷农药 mev-inphos (Mev) 作为实验损伤）描述了潜在的机制。在 Sprague-Dawley 大鼠中，蛋白质组学、蛋白质印迹和实时 PCR 分析表明，Mev 诱导 RVLM 中 HSP60 或 HSP70 的从头合成，而不影响 HSP90 水平。使用抗血清或反义寡核苷酸对 RVLM 中的 HSP60 或 HSP70 进行功能丧失操作可增强 Mev 引发的心血管抑郁，同时减少一氧化氮合酶 (NOS) I/蛋白激酶 G 信号传导，增强 NOS II/过氧亚硝酸盐级联，增强核小体 DNA 片段化，升高细胞质组蛋白相关 DNA 片段或激活 caspase-3，并增强细胞色素RVLM 中细胞凋亡信号传导的 c/caspase-3 级联。免疫共沉淀实验进一步揭示，在 Mev 中毒期间，HSP60 与线粒体或胞质 Bax 或线粒体 Bcl-2 之间形成的复合物逐渐增加，同时胞质 HSP60-Bcl-2 复合物解离。我们得出的结论是，HSP60 和 HSP70 通过 RVLM 中的抗凋亡作用改善心血管抑郁，从而提供针对 Mev 中毒的神经保护作用。可能的潜在细胞内过程包括增强 NOS I/蛋白激酶 G 信号传导和抑制 NOS II/过氧亚硝酸盐级联。此外，HSP60 通过减弱 Mev 诱导的 Bax/细胞色素 c/caspase-3 级联激活来发挥抗细胞凋亡作用。
The cellular and molecular basis of brain stem death remains an enigma. As the origin of a "life-and-death" signal that reflects the progression toward brain stem death, the rostral ventrolateral medulla (RVLM) is a suitable neural substrate for mechanistic delineation of this phenomenon. Here, we evaluated the hypothesis that heat shock proteins (HSPs) play a neuroprotective role in the RVLM during brain stem death and delineated the underlying mechanisms, using a clinically relevant animal model that employed the organophosphate pesticide mev-inphos (Mev) as the experimental insult. In Sprague-Dawley rats, proteomic, Western blot, and real-time PCR analyses demonstrated that Mev induced de novo synthesis of HSP60 or HSP70 in the RVLM without affecting HSP90 level. Loss-of-function manipulations of HSP60 or HSP70 in the RVLM using antiserum or antisense oligonucleotide potentiated Mev-elicited cardiovascular depression alongside reduced nitric-oxide synthase (NOS) I/protein kinase G signaling, enhanced NOS II/peroxynitrite cascade, intensified nucleosomal DNA fragmentation, elevated cytoplasmic histone-associated DNA fragments or activated caspase-3, and augmented the cytochrome c/caspase-3 cascade of apoptotic signaling in the RVLM. Co-immunoprecipitation experiments further revealed a progressive increase in the complex formed between HSP60 and mitochondrial or cytosolic Bax or mitochondrial Bcl-2 during Mev intoxication, alongside a dissociation of the cytosolic HSP60-Bcl-2 complex. We conclude that HSP60 and HSP70 confer neuroprotection against Mev intoxication by ameliorating cardiovascular depression via an anti-apoptotic action in the RVLM. The possible underlying intracellular processes include enhancing NOS I/protein kinase G signaling and inhibiting the NOS II/peroxynitrite cascade. In addition, HSP60 exerts its effects against apoptosis by blunting Mev-induced activation of the Bax/cytochrome c/caspase-3 cascade.