Department of Pharmacology, Xi'an Jiaotong University School of Medicine, Xi'an, China.
Am J Physiol Heart Circ Physiol. 2012 Nov 15;303(10):H1263-72. doi: 10.1152/ajpheart.00306.2012. Epub 2012 Sep 14.
Transient activation of p38 through anisomycin is demonstrated to precondition the heart against myocardial injury. However, it remains unknown whether specific TNF-α receptor (TNFR) p55/p75 and Nox2, a subunit of NADPH oxidase, are involved in this event. We sought to investigate whether the genetic disruption of TNFRp55/p75 and Nox2 eliminated cardioprotection elicited by anisomycin and whether p38-dependent activation of Nox2 stimulated TNFR to ultimately achieve protective effects. Adult wild-type and TNFR p55/p75(-/-) and Nox2(-/-) mice received intraperitoneal injections of anisomycin (0.1 mg/kg), a potent activator of p38. The hearts were subjected to 30 min myocardial ischemia/30 min reperfusion in the Langendorff perfused heart after 24 h. Left ventricular function was measured, and infarct size was determined. Myocardial TNF-α protein, Nox2, and superoxides releases were detected. Gel kinase assay was employed to detect the effect of p38 on Nox2 phosphorylation. Activation of p38 through anisomycin produces marked improvements in left ventricular functional recovery, and the reduction of myocardial infarction, which were abrogated by disruption of Nox2 and TNFR p55/p75. Disruption of Nox2 and TNFR p55/p75 abolished the effect of anisomycin-induced reduction of infarct size. Anisomycin induced the production of TNF-α, which was abrogated in Nox2(-/-) mice and by treatment with SB203580, but not by disruption of p55/p75. Anisomycin treatment resulted in an increase in Nox2 protein and the phosphorylation of Nox2, which was blocked by inhibition of p38. Taken together, these results indicate that stimulation of the Nox2 and TNFR p55/p75 pathway is a novel approach to anisomycin-induced cardioprotection.
通过使用放线菌酮短暂激活 p38 已被证明可以使心脏对心肌损伤产生预处理作用。然而，目前尚不清楚 TNF-α 受体（TNFR）p55/p75 和 Nox2（NADPH 氧化酶的一个亚基）是否参与了这一事件。我们试图研究 TNFRp55/p75 和 Nox2 的基因缺失是否消除了放线菌酮引起的心脏保护作用，以及 p38 依赖性的 Nox2 激活是否刺激了 TNFR 以最终实现保护作用。成年野生型和 TNFR p55/p75(-/-)和 Nox2(-/-)小鼠接受腹膜内注射放线菌酮（0.1 mg/kg），这是一种有效的 p38 激活剂。24 小时后，在 Langendorff 灌注心脏中进行 30 分钟心肌缺血/30 分钟再灌注。测量左心室功能，并确定梗塞面积。检测心肌 TNF-α 蛋白、Nox2 和超氧化物的释放。凝胶激酶测定法用于检测 p38 对 Nox2 磷酸化的影响。通过放线菌酮激活 p38 可显著改善左心室功能恢复，并减少心肌梗死，而 Nox2 和 TNFR p55/p75 的缺失则消除了这种作用。Nox2 和 TNFR p55/p75 的缺失消除了放线菌酮诱导的梗塞面积减少的作用。放线菌酮诱导 TNF-α 的产生，这种产生在 Nox2(-/-)小鼠中被消除，并且可以通过 SB203580 处理消除，但不能通过 p55/p75 的缺失消除。放线菌酮处理导致 Nox2 蛋白增加和 Nox2 磷酸化增加，这一过程被 p38 抑制所阻断。总之，这些结果表明，刺激 Nox2 和 TNFR p55/p75 途径是放线菌酮诱导心脏保护的一种新方法。
