Thrombopoietin protects H9C2 cells from excessive autophagy and apoptosis in doxorubicin‑induced cardiotoxicity

Abstract

Cardiac toxicity has been the major concern when using doxorubicin (DOX) in cancer therapy. Thrombopoietin (TPO) protects cardiac cells from DOX-induced cell damage; however, its molecular mechanism remains exclusive. The anti-autophagic and anti-apoptotic effects of TPO upon DOX treatment were studied in the cardiac H9C2 cell line, with bafilomycin A1 treatment as a positive control for autophagy inhibition. Cell viability was measured by Cell Counting Kit-8 assay in different treatment groups. The mRNA and/or protein levels of apoptotic markers and autophagy-associated factors were detected. The mean number of microtubule-associated protein 1A/1B-light chain 3 (LC3) puncta per cell was quantified to indicate autophagosomes and autolysosomes, of which the ones co-stained with lysosomal-associated membrane protein 1 were considered as autolysosomes. DOX treatment (5 µg/ml, 24 h) significantly impaired H9C2 cell viability compared with the control, while TPO pretreatment (10 ng/ml, 36 h) improved cell viability upon DOX treatment. DOX exposure markedly increased LC3 puncta in H9C2 cells, and TPO pretreatment reduced the number of autophagosomes, but showed no significant inhibitory effect on autolysosome formation. The autophagy inhibition by TPO upon DOX treatment was confirmed according to protein quantification of LC3-II and nucleoporin 62. TPO also suppressed autophagy-promoting protein Beclin-1, and elevated the anti-autophagic factors GATA-binding protein-4 and B cell lymphoma-2. Furthermore, TPO reduced DOX-induced apoptosis in H9C2 cells, as reflected by the amount changes of caspase-3. Taken together, these results revealed that TPO has a protective role in H9C2 cells from DOX-induced autophagy as well as apoptosis, and indicated that TPO may act as a cardioprotective drug in DOX-treated patients.

miR-146a attenuates apoptosis and modulates autophagy by targeting TAF9b/P53 pathway in doxorubicin-induced cardiotoxicity

“…Zilinyi et al 37 used Metformin to restore autophagy and partially reversed the myocardial damage of DOX through AMPK pathway. However, there were still many voices believing that DOX produced myocardial toxicity by upregulating autophagy rather than inhibiting autophagy flux due to differences in dose and time of administration 38,39 . Therefore, we adopted a low-dose long-term intervention, which made the experimental conditions in vitro and in vivo in line with the clinically chronic DOX-induced cardiomyopathy patients.…”

c-Mpl and TPO expression in the human central nervous system neurons inhibits neuronal apoptosis

“…Our previous data from a rat model demonstrated that TPO reduces damage to heart tissues caused by doxorubicin-induced cardiotoxicity and reduces myocardial infarction damage [11,40]. TPO also protects against iron overload-induced apoptosis by inhibiting oxidative stress and suppressing mitochondrial pathways in cardiomyocytes [41] and protects H9C2 cells from excessive autophagy and apoptosis in doxorubicininduced cardiotoxicity [11,42]. TPO also confers immediate protection to human cardiomyocytes against injury from hypoxia/reoxygenation by…”

Qi-Li-Qiang-Xin Alleviates Isoproterenol-Induced Myocardial Injury by Inhibiting Excessive Autophagy via Activating AKT/mTOR Pathway

“…The exact evidence has indicated that concentrations of catecholamines are elevated in the development of heart failure, resulting in morphological alterations of the heart or left ventricular hypertrophy (Bristow et al, 1985; Lefkowitz et al, 2000). Isoproterenol (ISO), one of the catecholamine adrenergic receptor agonists, has been proved to cause myocardial necrosis, cardiac hypertrophy, fibroblast proliferation, and abnormality of diastolic and systolic functions by subcutaneous injection, and these changes of heart induced by ISO can mimic the pathological changes of cardiac tissue in the process of human heart failure (Benjamin et al, 1989; Oudit et al, 2003; Christian et al, 2005; Wang et al, 2018). Therefore, the model of ISO-induced myocardial injury has been widely used in exploring the beneficial effect of drugs on cardiac dysfunction.…”

“…Therefore, enhancing autophagy at a moderate level could protect against hemodynamic or neurohormonal stresses in the process of heart failure (Kourtis and Tavernarakis, 2009; Zilinyi et al, 2018). However, excessive activation of autophagy leads to excessive self-digestion and degradation of essential cellular constituents, which could cause autophagic cell death (Gustafsson and Gottlieb, 2009; Sciarretta et al, 2018; Wang et al, 2018). Zhu et al found that cardiac autophagy triggered by chronic load was an inadaptable response that contributed to the progression of heart failure (Zhu et al, 2007).…”