Ren Jun, Babcock Sara A, Li Qun, Huff Anna F, Li Shi-Yan, Doser Thomas A
Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, School of Pharmacy, Laramie, WY 82071, USA.
Toxicol Lett. 2009 Jun 22;187(3):149-56. doi: 10.1016/j.toxlet.2009.02.019. Epub 2009 Mar 9.
Chronic intake of alcohol results in multiple organ damage including brain. This study was designed to examine the impact of facilitated acetaldehyde breakdown via transgenic overexpression of mitochondrial aldehyde dehydrogenase-2 (ALDH2) on alcohol-induced cerebral cortical injury. ALDH2 transgenic mice were produced using the chicken beta-actin promoter. Wild-type FVB and ALDH2 mice were placed on a 4% alcohol or control diet for 12 weeks. Protein damage and apoptosis were evaluated with carbonyl formation, caspase and TUNEL assays. Western blot was performed to examine expression (or its activation) of ALDH2, the pro- and anti-apoptotic proteins caspase-8, Bax, Bcl-2, Omi/HtrA2, apoptosis repressor with caspase recruitment domain (ARC), FLICE-like inhibitory protein (FLIP), X-linked inhibitor of apoptosis protein (XIAP), Akt, glycogen synthase kinase-3beta (GSK-3beta), p38, c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK). Chronic alcohol intake led to elevated apoptosis in the absence of overt protein damage, the effect of which was ablated by the overexpression of ALDH2 transgene. Consistently, ALDH2 transgene significantly attenuated alcohol-induced upregulation of Bax, Omi/HtrA2 and XIAP as well as downregulation of Bcl-2 and ARC without affecting alcohol-induced increase of FLIP in cerebral cortex. Phosphorylation of Akt and GSK-3beta was dampened while total/phosphorylated JNK and p38 phosphorylation were elevated following chronic alcohol intake, the effects of which were abrogated by ALDH2 transgene. Expression of total Akt, GSK-3beta, p38 and ERK (total or phosphorylated) was not affected by either chronic alcohol intake or ALDH2 transgene. Our results suggested that transgenic overexpression of ALDH2 rescues chronic alcoholism-elicited cerebral injury possibly via a mechanism associated with Akt, GSK-3beta, p38 and JNK signaling.
长期摄入酒精会导致包括大脑在内的多个器官受损。本研究旨在通过线粒体乙醛脱氢酶-2（ALDH2）转基因过表达促进乙醛分解，来研究其对酒精诱导的大脑皮质损伤的影响。使用鸡β-肌动蛋白启动子制备ALDH2转基因小鼠。将野生型FVB小鼠和ALDH2小鼠置于含4%酒精的饮食或对照饮食中12周。通过羰基形成、半胱天冬酶和TUNEL检测评估蛋白质损伤和细胞凋亡。进行蛋白质印迹法检测ALDH2、促凋亡和抗凋亡蛋白半胱天冬酶-8、Bax、Bcl-2、Omi/HtrA2、含半胱天冬酶募集结构域的凋亡抑制蛋白（ARC）、类FLICE抑制蛋白（FLIP）、X连锁凋亡抑制蛋白（XIAP）、Akt、糖原合酶激酶-3β（GSK-3β）、p38、c-Jun氨基末端激酶（JNK）和细胞外信号调节激酶（ERK）的表达（或其激活情况）。长期摄入酒精在无明显蛋白质损伤的情况下导致细胞凋亡增加，而ALDH2转基因过表达可消除这种影响。一致地，ALDH2转基因显著减弱了酒精诱导的大脑皮质中Bax、Omi/HtrA2和XIAP的上调以及Bcl-2和ARC的下调，而不影响酒精诱导的FLIP增加。长期摄入酒精后，Akt和GSK-3β的磷酸化受到抑制，而总JNK/磷酸化JNK以及p38磷酸化水平升高，ALDH2转基因可消除这些影响。长期摄入酒精或ALDH2转基因均不影响总Akt、GSK-3β、p38和ERK（总或磷酸化形式）的表达。我们的结果表明，ALDH2转基因过表达可能通过与Akt、GSK-3β、p38和JNK信号相关的机制挽救慢性酒精中毒引起的脑损伤。
