PI3 kinase and not p42/p44 appears to be implicated in the protection conferred by ischemic preconditioning
PI3 kinase and not p42/p44 appears to be implicated in the protection conferred by ischemic preconditioning
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DOI：
10.1006/jmcc.2002.2006
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发表时间：
2002-06-01
影响因子：
5
通讯作者：
Yellon, DM
中科院分区：
文献类型：
--
作者：
Mocanu, MM;Bell, RM;Yellon, DM
缺血预处理导致对致死性缺血/再灌注损伤的即刻保护，该损伤包括不可逆的坏死和程序性细胞死亡，即凋亡。我们假设预处理可能通过诱导磷脂酰肌醇3-OH激酶（PI 3激酶）或p42/p44细胞外受体激酶激活公认的抗凋亡途径，从而减弱总细胞死亡。离体灌流大鼠心脏预处理两个周期的5分钟缺血和10分钟再灌注。然后将它们冷冻用于Western印迹分析或在评估梗死面积之前进行35分钟的局部缺血和120分钟的再灌注。选择性PI 3激酶抑制剂wortmannin（W，100 nM）和LY 294002（LY，15 μ M）以及p42/p44抑制剂PD 98059（PD，10和50 μ M）在预处理方案期间单独输注。另一组心脏接受两种抑制剂（W和PD）。结果表示为危险区内梗死的百分比。W或LY抑制PI 3激酶可部分消除缺血预处理的梗死保护作用（1/R%：C组44.6 ± 2.7，IP组17.6 ± 2.0，vs W组32.2 ± 4.2，LY组30.9 ± 2.6，P < 0.05）。然而，抑制ERK磷酸化对梗死面积的减少没有显著影响（缺血预处理组为17.6 ± 2.0，IP + 10 μ M PD组为21.4 ± 3.0，IP + 50 μ M PD组为15.2 ± 1.4，P > 0.05）。Western blot分析证实PD和LY分别抑制p42/p44和AKT的磷酸化。PD + W联合抑制不能进一步减弱保护作用（27.6 ± 1.3%，P > 0.1）。这些数据似乎表明，P13激酶，而不是p42/p44级联，是牵连在早期缺血预处理。(C)2002爱思唯尔科技有限公司版权所有。
Ischemic preconditioning results in an immediate phase of protection against lethal ischemia/reperfusion injury that is comprised of both irreversible necrosis and programmed cell death, apoptosis. We hypothesized that preconditioning may activate putative anti-apoptotic pathways, through the induction of either phosphatidyl inositol 3-OH kinase (PI3 kinase) or p42/p44 extracellular receptor kinase, attenuating total cell death. Isolated perfused rat hearts were preconditioned with two cycles of 5 min ischemia and 10 min reperfusion. Then they were frozen for Western blot analysis or subjected to 35 min regional ischemia and 120 min reperfusion prior to infarct size assessment. Selective PI3 kinase inhibitors, wortmannin (W, 100 nM) and LY294002 (LY, 15 muM) and the p42/p44 inhibitor, PD 98059 (PD, 10 and 50 muM), were individually infused during the preconditioning protocol. One further group of hearts received both inhibitors (W and PD). The results were expressed as percentage of infarction within the risk zone. Inhibition of PI3 kinase by either W or LY partially abrogated the infarct sparing effect of ischemic preconditioning (1/R%: 44.6+/-2.7 in C, 17.6+/-2.0 in IP, vs 32.2+/-4.2 in W, and 30.9+/-2.6 in LY, P < 0.05). Inhibition of ERK phosphorylation however, had no significant effect upon infarct size reduction (17.6+/-2.0 in ischemic preconditioning vs 21.4+/-3.0 in IP + 10 muM PD and 15.2+/-1.4 in IP + 50 muM PD, P > 0.05). Western blot analysis confirmed that PD abrogated the phosphorylation of p42/p44 and LY the phosphorylation of AKT. Combined inhibition with PD + W failed to further attenuate protection (27.6+/-1.3%, P > 0.1). These data appear to demonstrate that the P13 kinase, but not the p42/p44 cascade, is implicated in early ischemic preconditioning. (C) 2002 Elsevier Science Ltd. All rights reserved.