Activation of volume-sensitive Cl− channel mediates autophagy-related cell death in myocardial ischaemia/reperfusion injury

Abstract

Excessive reactive oxygen species (ROS) plays an important role in myocardial ischemia/reperfusion (I/R) injury, which triggers not only myocardial cellular apoptosis but also autophagy-related cell death, in which volume-sensitive outwardly rectifying (VSOR) Cl− channel-activated by ROS contributes to cell apoptotic volume decrease, playing an incipient incident of cellular apoptosis. However, whether VSOR Cl− channel concurrently participates in autophagy-related cell death regulation remains unclear. To illuminate the issue, studies underwent in myocardial vitro and vivo I/R model. Rats were performed to ischemia 30 minutes and subsequent reperfusion 24-96 hours, ROS scavenger (NAC), VSOR Cl− channel blocker (DCPIB) and autophagy inhibitor (3MA) were administered respectively. Results showed that oxidative stress, LC3-II stain and inflammation in myocardial tissue were markedly increased, lysosome associated membrane protein-2 (LAMP2) were significantly reduced with I/R group as compared with sham group, reperfusion significantly led to damage in myocardial tissue and heart function, whereas the disorder could be rescued through these agents. Moreover, primary neonatal rat cardiomyocytes hypoxia/reoxygenation model were administered, results showed that VSOR Cl− channel-activated by reoxygenation could cause both cell volume decrease and intracellular acidification, which further increased LC3 and depleted of LAMP2, resulting in autophagy-related cell death. Interestingly, VSOR Cl− channel-blocked by DCPIB could stably maintain the cell volume, intracellular pH, abundant LAMP2 and autophagic intensity regardless of ROS intension derived from reoxygenation injury or adding H2O2. These results first demonstrate that VSOR Cl− channel-activated is a pivotal event to trigger autophagy-related death, which reveals a novel therapeutic target to decrease myocardial I/R injury.

Activation of G protein‐coupled oestrogen receptor 1 at the onset of reperfusion protects the myocardium against ischemia/reperfusion injury by reducing mitochondrial dysfunction and mitophagy

“…We also found that administration of 3‐MA alone reduced myocardial infarct size versus control, a result similar to that obtained by Xia et al . () but opposite to the report from Ling et al . (), who used 50 times our dose.…”

“…(Korkmaz et al, ) that acts via the MEK/ERK pathway (Pattingre et al, ) and 3‐Methyladenine (3‐MA, 0.3 mg·kg −1 b.w. ; Xia et al, ), also well known as a class I and III inhibitor of PI‐3K that inhibits autophagy (Wu et al, ) as shown in Figure A. We found that addition of U0126 slightly reduced myocardial infarct (MI) size, while 3‐MA infusion decreased MI as compared to control Figure B–E.…”

Cell Volume-Activated and Volume-Correlated Anion Channels in Mammalian Cells: Their Biophysical, Molecular, and Pharmacological Properties

“…4, type B mechanism). Swelling-independent, H 2 O 2 -induced activation of VSOR was originally found independently in 2004 by three groups (Browe and Baumgarten, 2004;Shimizu et al, 2004;Varela et al, 2004) and was confirmed by subsequent studies (Wang et al, 2005;Jiao et al, 2006;Varela et al, 2007;Harrigan et al, 2008;Liu et al, 2009;Deng et al, 2010a,b;Crutzen et al, 2012;Holm et al, 2013;Shen et al, 2014;Xia et al, 2016;Wang et al, 2017a,b). In addition, for the first time, VSOR per se was identified as the anion channel responsible for the Cl 2 efflux causing apoptotic cell shrinkage, called AVD , which was observed after stimulation with an intrinsic mitochondrion-mediated apoptosis inducer (staurosporine) due to increased ROS production via NAD(P)H oxidase (NOX) (Fig.…”

Circulating Levels of LAMP2 in Coronary Artery Disease: Association with Serum Lipid Profile

“…Several lines of evidence have demonstrated that LAMP2 deficiency leads to the accumulation of CE in the cells, through which it will induce the formation of foam cells in the case of macrophages [10,11]. Moreover, LAMP2, which is a major player in autophagy process, has been upregulated in ischemic and inflammatory conditions [16,17,25]. It has been hypothesized that enhancement of autophagy could have a protective effect in aforementioned conditions.…”

“…LAMP2 mutation is the main cause of Danon disease, which with its typical characteristics include cardiomyopathy along with skeletal myopathy and mental retardation [15]. Several lines of evidence have demonstrated altered expression of autophagy-associated proteins including LAMP2 in inflammatory conditions [16,17]. Since CAD is considered an inflammatory disease, it is expected, that circulating levels of LAMP2 might be associated with pathogenesis of CAD.…”