Jiangxi Provincial Key Laboratory of Basic Pharmacology, School of Pharmaceutical Science, Nanchang University, Nanchang 330006, PR China; Queen Mary School, Jiangxi Medical College, Nanchang University, Nanchang 330006, P.R. China.
Jiangxi University of Traditional Chinese Medicine, Nanchang 330000, PR China.
Eur J Pharmacol. 2019 Jan 15;843:80-87. doi: 10.1016/j.ejphar.2018.11.016. Epub 2018 Nov 14.
Our previous studies showed that the effect of resveratrol preventing mitochondrial permeability transition pore (mPTP) opening in myocardial ischemia/reperfusion injury was achieved by regulating voltage-dependent anion channel 1 (VDAC1). However, the underlying mechanism remains unclear. Previous studies demonstrated that the activity and function of VDAC1 are highly regulated by post-translational modification. In present study, we investigated whether resveratrol modulates VDAC1 phosphorylation to achieve cardioprotection and explored the signaling pathways involved. Our findings demonstrated that anoxia/reoxygenation (A/R) treatment, an ischemia/reperfusion model in vitro, enhanced VDAC1 phosphorylation in cardiomyocytes. Moreover, we found phosphorylated VDAC1 showed increased affinity to Bax, whereas interaction with hexokinase 2 (HK2) was reduced. Accordingly, the generation of reactive oxygen species increased, the mitochondrial membrane potential collapsed, mPTP opening increased and cytochrome c released into cytoplasm, thereby leading to increased apoptosis. Moreover, our data showed that pretreatment with resveratrol prior to A/R injury inhibited VDAC1 phosphorylation. Dephosphorylated VDAC1 using pretreated resveratrol promoted dissociation with Bax and binding to HK2, which subsequently protected cardiomyocytes against A/R injury. In addition, Akt and its downstream glycogen synthase kinase 3 β (GSK3β) were phosphorylated by the action of resveratrol. Akt inhibitor IV abrogated Akt-GSK3β phosphorylation and thereby abolished the dephosphorylation activity of resveratrol on VDAC1. Moreover, all resveratrol-mediated protective effects on A/R injured cardiomyocytes were abolished by Akt inhibitor IV. Taken together, our data indicated that A/R injury enhanced VDAC1 phosphorylation in cardiomyocytes, whereas pretreatment with resveratrol dephosphorylated VDAC1 through the Akt-GSK3β pathway, thereby protecting cardiomyocytes against A/R injury.
我们之前的研究表明，白藜芦醇通过调节电压依赖性阴离子通道 1（VDAC1）来防止心肌缺血/再灌注损伤中的线粒体通透性转换孔（mPTP）开放。然而，其潜在机制尚不清楚。先前的研究表明，VDAC1 的活性和功能受到翻译后修饰的高度调节。在本研究中，我们研究了白藜芦醇是否通过调节 VDAC1 的磷酸化来实现心脏保护作用，并探讨了相关的信号通路。我们的研究结果表明，缺氧/复氧（A/R）处理，一种体外的缺血/再灌注模型，增强了心肌细胞中 VDAC1 的磷酸化。此外，我们发现磷酸化的 VDAC1 与 Bax 的亲和力增加，而与己糖激酶 2（HK2）的相互作用减少。因此，活性氧的产生增加，线粒体膜电位崩溃，mPTP 打开增加，细胞色素 c 释放到细胞质中，导致细胞凋亡增加。此外，我们的数据表明，在 A/R 损伤前用白藜芦醇预处理可抑制 VDAC1 的磷酸化。用预处理的白藜芦醇使 VDAC1 去磷酸化，促进与 Bax 的解离，并与 HK2 结合，从而保护心肌细胞免受 A/R 损伤。此外，白藜芦醇的作用使 Akt 及其下游糖原合酶激酶 3β（GSK3β）磷酸化。Akt 抑制剂 IV 阻断 Akt-GSK3β 磷酸化，从而消除了白藜芦醇对 VDAC1 的去磷酸化作用。此外，Akt 抑制剂 IV 消除了白藜芦醇对 A/R 损伤心肌细胞的所有保护作用。综上所述，我们的数据表明，A/R 损伤增强了心肌细胞中 VDAC1 的磷酸化，而白藜芦醇预处理通过 Akt-GSK3β 通路使 VDAC1 去磷酸化，从而保护心肌细胞免受 A/R 损伤。
