Akt activation protects rat liver from ischemia/reperfusion injury
Akt activation protects rat liver from ischemia/reperfusion injury
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DOI：
10.1016/j.jss.2004.04.016
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发表时间：
2004-10-01
影响因子：
2.2
通讯作者：
Yamaoka, Y
中科院分区：
文献类型：
--
作者：
Harada, N;Hatano, E;Yamaoka, Y
背景肝细胞凋亡和坏死在肝缺血再灌注损伤中起重要作用。Akt是一种丝氨酸-苏氨酸蛋白激酶，已知可促进细胞存活。我们研究了组成性激活或显性失活Akt的基因转移是否会影响肝I/R损伤。采用Pringle's手法造成大鼠肝I/R损伤20 min后再灌注。在肝I/R前72 h通过尾静脉注射编码Akt组成型活性形式（myrAkt）、Akt显性阴性形式（dnAkt）或β-半乳糖苷酶（LacZ）的腺病毒。末端脱氧核苷酸转移酶介导的dUTP-生物素缺口末端标记（TUNEL）染色显示，在再灌注后240分钟的阳性细胞显着增加。磷酸化Akt抗体免疫印迹显示Akt在再灌注后90至180分钟磷酸化。myrAkt的表达减少了再灌注后肝脏中央静脉周围TUNEL阳性细胞的数量和肝坏死。与未感染大鼠（1761 +/- 671 IUAL）、LacZ腺病毒（1528 +/-671 IU/L）和dnAkt腺病毒（1342 +/- 485 IU/L）感染大鼠相比，这种表达还显著抑制了I/R后120 min血清丙氨酸氨基转移酶的升高（297 +/- 131 IU/L，P < 0.05）。MyrAkt表达使Bad磷酸化，抑制再灌注后细胞色素c的释放。核因子（NF）-κ B、p65的核转位在三组大鼠间无差异。腺病毒介导的myrAkt基因转移可通过Bad而不是NF-κ B抑制大鼠肝细胞凋亡和随后的肝I/R损伤。(C)2004爱思唯尔公司All rights reserved.
Background. Apoptosis as well as necrosis may play an important role in hepatic ischemia/reperfusion (I/R) injury. Akt, a serine-threonine protein kinase, is known to promote cell survival. We investigated whether gene transfer of constitutively active or dominant negative Akt could affect hepatic I/R injury.Materials and methods. Hepatic I/R injury was induced in rats by Pringle's maneuver for 20 min followed by reperfusion. Adenoviruses encoding a constitutively active form of Akt (myrAkt), a dominant negative form of Akt (dnAkt), or beta-galactosidase (LacZ) were injected through the tail vein 72 h before hepatic I/R.Results. Terminal deoxynucleotidyl transferasemediated dUTP-biotin nick-end labeling (TUNEL) staining demonstrated a significant increase in the positive cells 240 min after reperfusion. Immunoblotting with phospho-Akt antibody showed phosphorylation of Akt from 90 to 180 min after reperfusion. The expression of myrAkt reduced the number of TUNEL-positive cells and hepatic necrosis around the central veins in the liver after reperfusion. This expression also significantly inhibited the increase in serum alanine aminotransferase (297 +/- 131 IU/L, P < 0.05) 120 min after I/R, compared with increases in uninfected (1761 +/- 671 IUAL), LacZ adenovirus (1528 +/- 671 IU/L)-, and dnAkt adenovirus (1342 +/- 485 IU/L)-infected rats. MyrAkt expression phosphorylated Bad and inhibited the release of cytochrome-c after reperfusion. No difference in nuclear translocation of nuclear factor (NF)-KB, p65 was seen among the three groups of rats, however.Conclusion. Adenoviral gene transfer of myrAkt could inhibit apoptotic cell death and subsequent hepatic I/R injury in the rat, through Bad, not NF-KB. (C) 2004 Elsevier Inc. All rights reserved.