Melatonin and cardioprotection against ischaemia/reperfusion injury: What's new? A review

J Cellular Molecular Medi

Park

et al. 2020

There are increasing concerns related to the cardiotoxicity of doxorubicin in the clinical setting. Recently, melatonin has been shown to exert a cardioprotective effect in various cardiovascular diseases, including cardiotoxic conditions. In this study, we examined the possible protective effects of melatonin on doxorubicin‐induced cardiotoxicity and explored the underlying mechanisms related to this process. We found that in vitro doxorubicin treatment significantly decreased H9c2 cell viability and induced apoptosis as manifested by increased TUNEL‐positive cells, down‐regulation of anti‐apoptotic protein Bcl‐2, as well as up‐regulation of pro‐apoptotic protein Bax. This was associated with increased reactive oxygen species (ROS) levels and decreased mitochondrial membrane potentials (MMP). In vivo, five weeks of doxorubicin treatment significantly decreased cardiac function, as evaluated by echocardiography. TUNEL staining results confirmed the increased apoptosis caused by doxorubicin. On the other hand, combinational treatment of doxorubicin with melatonin decreased cardiomyocyte ROS and apoptosis levels, along with increasing MMP. Such doxorubicin‐melatonin co‐treatment alleviated in vivo doxorubicin‐induced cardiac injury. Western Blots, along with in vitro immunofluorescence and in vivo immunohistochemical staining confirmed that doxorubicin treatment significantly down‐regulated Yes‐associated protein (YAP) expression, while YAP levels were maintained under co‐treatment of doxorubicin and melatonin. YAP inhibition by siRNA abolished the protective effects of melatonin on doxorubicin‐treated cardiomyocytes, with reversed ROS level and apoptosis. Our findings suggested that melatonin treatment attenuated doxorubicin‐induced cardiotoxicity through preserving YAP levels, which in turn decreases oxidative stress and apoptosis.

Section: Discussionmentioning

confidence: 99%

Melatonin attenuates doxorubicin‐induced cardiotoxicity through preservation of YAP expression

J Cellular Molecular Medi

Park

et al. 2020

“…The cells were then centrifuged for 10 min at 12,000 rpm at 4°C. After quantification of protein concentration using BCA assay, equal amounts of protein were loaded on 10-12% gels for sodium dodecyl sulfate polyacrylamide gel electrophoresis separation (Cieri et al, 2018), followed by transferring onto PVDF membranes (Lochner, Marais, & Huisamen, 2018). The 5% dry milk/Tris-buffered saline with Tween-20 (TBST) solution was used to block the membranes and primary antibodies in 5% dry milk/TBST (Leeboonngam, Pramong, Sae-Ung, Govitrapong, & Phansuwan-Pujito, 2018), were then added.…”

Section: Western Blot Analysismentioning

confidence: 99%

PTEN inhibition attenuates endothelial cell apoptosis in coronary heart disease via modulating the AMPK–CREB–Mfn2‐mitophagy signaling pathway

Journal Cellular Physiology

Zhao

et al. 2019

Atherosclerosis (AS) is a major pathogenic factor in patients with cardiovascular diseases, and endothelial dysfunction (ED) plays a primary role in the occurrence and development of AS. In our study, we attempted to evaluate the role of phosphatase and tensin homolog (PTEN) in endothelial cell apoptosis under oxidized low-density lipoprotein (ox-LDL) stimulation and identify the associated mechanisms. The results of our study demonstrated that ox-LDL induced human umbilical vein endothelial cell (HUVEC) death via mitochondrial apoptosis, as evidenced by reduced mitochondrial potential, increased mitochondria permeability transition pore opening, cellular calcium overload, and caspase-9/-3 activation. In addition, ox-LDL also suppressed cellular energy production via downregulating the mitochondrial respiratory complex. Moreover, ox-LDL impaired HUVECs migration. Western blot analysis showed that PTEN expression was upregulated after exposure to ox-LDL and knockdown of PTEN could attenuate ox-LDL-mediated endothelial cell damage. Furthermore, we found that ox-LDL impaired mitophagy activity, whereas PTEN deletion could improve mitophagic flux and this effect relied on the activity of the AMPactivated protein kinase (AMPK)-cAMP-response element-binding protein (CREB)-Mitofusin-2 (Mfn2) axis. When the AMPK-CREB-Mfn2 pathway was inhibited, PTEN deletion-associated HUVECs protection was significantly reduced, suggesting that the AMPK-CREB-Mfn2-mitophagy axis is required for PTEN deletion-mediated endothelial cell survival under ox-LDL. Taken together, our results indicate that ox-LDL-induced endothelial cell damage is associated with PTEN overexpression, and inhibition of PTEN could promote endothelial survival via activating the AMPK-CREB-Mfn2-mitophagy signaling pathway. K E Y W O R D S AMPK-CREB-Mfn2 signaling pathway, endothelial cell dysfunction, Mfn2, mitophagy, ox-LDL, PTEN

“…5,6 They are mainly found in the pineal gland and also other organs such as brain, eye, skin, stomach, and heart, suggesting that melatonin might have various effects in different organs besides brain. 5 Indeed, although the primary role of melatonin is to regulate circadian rhythms and the sleep-wake pattern, 7 its roles in antitumor, 8 anti-aging, [9][10][11][12] cerebral protection, 13,14 and cardioprotection [15][16][17][18] have been gradually recognized. Specifically, numerous animal as well as clinical studies have provided evidence of the beneficial effects of melatonin on MI/R [19][20][21][22] Most of these studies further corroborated that the cardioprotective effects of melatonin were mainly ascribed to melatonin membrane receptor activation by the utilization of a nonspecific melatonin receptor antagonist luzindole.…”

Section: Introductionmentioning

confidence: 99%

Activation of melatonin receptor 2 but not melatonin receptor 1 mediates melatonin‐conferred cardioprotection against myocardial ischemia/reperfusion injury

Han

Journal of Pineal Research

Chen

et al. 2019

Accumulated pieces of evidence have proved the beneficial effects of melatonin on myocardial ischemia/reperfusion (MI/R) injury, and these effects were largely dependent on melatonin membrane receptor activation. In humans and other mammals, there are two types of melatonin receptors, including the melatonin receptor 1 (MT1, melatonin receptor 1a or MTNR1A) and melatonin receptor 1 (MT2, melatonin receptor 1b or MTNR1B) receptor subtypes. However, which receptor mediates melatonin‐conferred cardioprotection remains unclear. In this study, we employed both loss‐of‐function and gain‐of‐function approaches to reveal the answer. Mice (wild‐type; MT1 or MT2 silencing by in vivo minicircle vector; and those overexpressing MT1 or MT2 by in vivo AAV9 vector) were exposed to MI/R injury. Both MT1 and MT2 were present in wild‐type myocardium. MT2, but not MT1, was essentially upregulated after MI/R Melatonin administration significantly reduced myocardial injury and improved cardiac function after MI/R Mechanistically, melatonin treatment suppressed MI/R‐initiated myocardial oxidative stress and nitrative stress, alleviated endoplasmic reticulum stress and mitochondrial injury, and inhibited myocardial apoptosis. These beneficial actions of melatonin were absent in MT2‐silenced heart, but not the MT1 subtype. Furthermore, AAV9‐mediated cardiomyocyte‐specific overexpression of MT2, but not MT1, mitigated MI/R injury and improved cardiac dysfunction, which was accompanied by significant amelioration of oxidative stress, endoplasmic reticulum stress, and mitochondrial dysfunction. Mechanistically, MT2 protected primary cardiomyocytes against hypoxia/reoxygenation injury via MT2/Notch1/Hes1/RORα signaling. Our study presents the first direct evidence that the MT2 subtype, but not MT1, is a novel endogenous cardiac protective receptor against MI/R injury. Medications specifically targeting MT2 may hold promise in fighting ischemic heart disease.