Evans Biomedical Research Center, Renal Section, Room 546, 650 Albany Street, Boston, MA 02118-2518, USA.
J Am Soc Nephrol. 2010 Feb;21(2):284-94. doi: 10.1681/ASN.2009080828. Epub 2010 Jan 21.
The mechanism by which the serine-threonine kinase glycogen synthase kinase-3beta (GSK3beta) affects survival of renal epithelial cells after acute stress is unknown. Using in vitro and in vivo models, we tested the hypothesis that GSK3beta promotes Bax-mediated apoptosis, contributing to tubular injury and organ dysfunction after acute renal ischemia. Exposure of renal epithelial cells to metabolic stress activated GSK3beta, Bax, and caspase 3 and induced apoptosis. Expression of a constitutively active GSK3beta mutant activated Bax and decreased cell survival after metabolic stress. In contrast, pharmacologic inhibition (4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione [TDZD-8]) or RNA interference-mediated knockdown of GSK3beta promoted cell survival. Furthermore, RNA interference-mediated knockdown of Bax abrogated the cell death induced by constitutively active GSK3beta. In a cell-free assay, TDZD-8 inhibited the phosphorylation of a peptide containing the Bax serine(163) site targeted by stress-activated GSK3beta. In rats, TDZD-8 inhibited ischemia-induced activation of GSK3beta, Bax, and caspase 3; ameliorated tubular and epithelial cell damage; and significantly protected renal function. Taken together, GSK3beta-mediated Bax activation induces apoptosis and tubular damage that contribute to acute ischemic kidney injury.
丝氨酸-苏氨酸激酶糖原合成酶激酶-3β（GSK3β）影响急性应激后肾上皮细胞存活的机制尚不清楚。我们使用体外和体内模型来检验以下假说，即 GSK3β促进 Bax 介导线粒体凋亡，导致急性肾缺血后肾小管损伤和器官功能障碍。代谢应激可使肾上皮细胞中 GSK3β、Bax 和半胱天冬酶 3 激活，并诱导细胞凋亡。表达组成性激活的 GSK3β突变体可在代谢应激后激活 Bax 并减少细胞存活。相反，药物抑制（4-苄基-2-甲基-1,2,4-噻二唑烷-3,5-二酮[TDZD-8]）或 RNA 干扰介导的 GSK3β敲低可促进细胞存活。此外，RNA 干扰介导的 Bax 敲低可消除组成性激活的 GSK3β诱导的细胞死亡。在无细胞测定中，TDZD-8 抑制应激激活的 GSK3β靶向的 Bax 丝氨酸（163）位点的肽的磷酸化。在大鼠中，TDZD-8 抑制缺血诱导的 GSK3β、Bax 和半胱天冬酶 3 的激活；改善肾小管和上皮细胞损伤；并显著保护肾功能。综上所述，GSK3β 介导的 Bax 激活诱导细胞凋亡和肾小管损伤，导致急性缺血性肾损伤。
