Lange Philipp S, Chavez Juan C, Pinto John T, Coppola Giovanni, Sun Chiao-Wang, Townes Tim M, Geschwind Daniel H, Ratan Rajiv R
Burke Medical Research Institute, White Plains, NY 10605, USA.
J Exp Med. 2008 May 12;205(5):1227-42. doi: 10.1084/jem.20071460. Epub 2008 May 5.
Oxidative stress is pathogenic in neurological diseases, including stroke. The identity of oxidative stress-inducible transcription factors and their role in propagating the death cascade are not well known. In an in vitro model of oxidative stress, the expression of the bZip transcription factor activating transcription factor 4 (ATF4) was induced by glutathione depletion and localized to the promoter of a putative death gene in neurons. Germline deletion of ATF4 resulted in a profound reduction in oxidative stress-induced gene expression and resistance to oxidative death. In neurons, ATF4 modulates an early, upstream event in the death pathway, as resistance to oxidative death by ATF4 deletion was associated with decreased consumption of the antioxidant glutathione. Forced expression of ATF4 was sufficient to promote cell death and loss of glutathione. In ATF4(-/-) neurons, restoration of ATF4 protein expression reinstated sensitivity to oxidative death. In addition, ATF4(-/-) mice experienced significantly smaller infarcts and improved behavioral recovery as compared with wild-type mice subjected to the same reductions in blood flow in a rodent model of ischemic stroke. Collectively, these findings establish ATF4 as a redox-regulated, prodeath transcriptional activator in the nervous system that propagates death responses to oxidative stress in vitro and to stroke in vivo.
氧化应激在包括中风在内的神经疾病中具有致病性。氧化应激诱导型转录因子的身份及其在传播死亡级联反应中的作用尚不清楚。在氧化应激的体外模型中,bZip转录因子激活转录因子4(ATF4)的表达通过谷胱甘肽耗竭诱导,并定位于神经元中一个假定死亡基因的启动子上。ATF4的种系缺失导致氧化应激诱导的基因表达显著降低以及对氧化死亡的抗性。在神经元中,ATF4调节死亡途径中的一个早期上游事件,因为通过缺失ATF4对氧化死亡的抗性与抗氧化剂谷胱甘肽的消耗减少有关。ATF4的强制表达足以促进细胞死亡和谷胱甘肽的丧失。在ATF4(-/-)神经元中,ATF4蛋白表达的恢复恢复了对氧化死亡的敏感性。此外,与在缺血性中风啮齿动物模型中经历相同血流减少的野生型小鼠相比,ATF4(-/-)小鼠的梗死灶明显更小,行为恢复更好。总体而言,这些发现确立了ATF4作为神经系统中一种氧化还原调节的促死亡转录激活因子,其在体外将死亡反应传播至氧化应激,在体内传播至中风。