Clinical use of the anti-cancer drug doxorubicin (DOX) is largely limited due to its severe cardiotoxicity. Dysregulation of autophagy is implicated in DOX-induced cardiotoxicity (DIC). Prior studies have indicated that Beclin1 and lysosomal-associated membrane proteins-1 (LAMP1) are critical mediators of autophagy. In this work, by assessing autophagic flux in a DOX-stimulated H9C2 model, we observed autolysosome accumulation caused by interruption of autolysosome degradation. Tanshinone IIA (TSA) is a well-known small molecule that exerts impressive cardioprotective effects on heart failure. Here, we investigated the regulation of TSA in DOX-treated zebrafish, mice, and H9C2 models. Results demonstrated that TSA remarkably improved heart function and reversed pathological changes in vivo, while TSA restored autophagic flux by promoting autolysosome degradation and autophagosome formation. Further experiments demonstrated that these effects were mediated through upregulation of Beclin1 and LAMP1. The mTOR agonist MHY1485 was shown to abrogate the effect of TSA via the UNC-51-like kinase 1 (ULK1)-Beclin1/TFEB-LAMP1 signaling pathway in vitro, demonstrating that TSA protects against DIC by promoting autophagy via the Beclin1/LAMP1 signaling pathway. We further employed a U87 model to assess whether TSA would compromise the antitumor activity of DOX. Intriguingly, the co-treatment of TSA was able to synergistically inhibit proliferative activity. Collectively, in this study we uncover the novel insight that TSA is able to reduce the cardiotoxicity of DOX without compromising antitumor activity.

Apoptosis plays a critical role in the progression of diabetic cardiomyopathy (DC). Astragalus polysaccharides (APS), an extract of astragalus membranaceus (AM), is an effective cardioprotectant. Currently, little is known about the detailed mechanisms underlying cardioprotective effects of APS. The aims of this study were to investigate the potential effects and mechanisms of APS on apoptosis employing a model of high glucose induction of apoptosis in H9C2 cells. A model of high glucose induction of H9C2 cell apoptosis was adopted in this research. The cell viabilities were analyzed by MTT assay, and the apoptotic response was quantified by flow cytometry. The expression levels of the apoptosis related proteins were determined by Real-time PCR and western blotting. Incubation of H9C2 cells with various concentrations of glucose (i.e., 5.5, 12.5, 25, 33 and 44 mmol/L) for 24 h revealed that cell viability was reduced by high glucose dose-dependently. Pretreatment of cells with APS could inhibit high glucose-induced H9C2 cell apoptosis by decreasing the expressions of caspases and the release of cytochrome C from mitochondria to cytoplasm. Further experiments also showed that APS could modulate the ratio of Bcl-2 to Bax in mitochondria. APS decreases high glucose-induced H9C2 cell apoptosis by inhibiting the expression of pro-apoptotic proteins of both the extrinsic and intrinsic pathways and modulating the ratio of Bcl-2 to Bax in mitochondria.

Cardiotoxicity is one of the main side effects of doxorubicin (Dox) treatment. Dox could induce oxidative stress, leading to an opening of the mitochondrial permeability transition pore (mPTP) and apoptosis in cardiomyocytes. Previous studies have shown that Cryptotanshinone (Cts) has potential cardioprotective effects, but its role in Dox-induced cardiotoxicity (DIC) remains unknown. A Dox-stimulated H9C2 cell model was established. The effects of Cts on cell viability, reactive oxygen species (ROS), superoxide ion accumulation, apoptosis and mitochondrial membrane potential (MMP) were evaluated. Expressions of proteins in Akt-GSK-3β pathway were detected by Western blot. An Akt inhibitor was applied to investigate the effects of Cts on the Akt-GSK-3β pathway. The effects of Cts on the binding of p-GSK-3β to ANT and the formation of the ANT-CypD complex were explored by immunoprecipitation assay. The results showed that Cts could increase cell viability, reduce ROS levels, inhibit apoptosis and protect mitochondrial membrane integrity. Cts increased phosphorylated levels of Akt and GSK-3β. After cells were co-treated with an Akt inhibitor, the effects of Cts were abolished. An immunoprecipitation assay showed that Cts significantly increased GSK-3β-ANT interaction and attenuated Dox-induced formation of the ANT-CypD complex, thereby inhibiting opening of the mPTP. In conclusion, Cts could ameliorate oxidative stress and apoptosis via the Akt-GSK-3β-mPTP pathway.

Background: Qishen granules (QSG) has been applied to treat heart failure (HF) for decades. Our previous transcriptomics study has suggested that Qishen granules (QSG) could regulate the pathways of cardiac energy metabolism in HF, but the specific regulatory mechanism has not yet been clarified. This study was to investigate the potential mechanism of QSG in regulating myocardial fatty acid (FA) and glucose metabolism in a rat model of HF. Methods: The model of HF was induced by left anterior descending coronary artery ligation. Cardiac structure and function were assessed by cine magnetic resonance imaging (MRI) and echocardiography. Level of glucose metabolism was non-invasively evaluated by ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT). Blood lipid levels were determined by enzymatic analysis. The mitochondrial ultrastructure was observed with a transmission electron microscope. The critical proteins related to FA metabolism, glucose metabolism and mitochondrial function were measured by western blotting. The ANOVA followed by a Fisher’s LSD test was used for within-group comparisons. Results: QSG ameliorated cardiac functions and attenuated myocardial remodeling in HF model. The levels of serum TC, TG and LDL-C were significantly reduced by QSG. The proteins mediating FA uptake, transportation into mitochondria and β-oxidation (FAT/CD36, CPT1A, ACADL, ACADM, ACAA2 and SCP2) as well as the upstreaming transcriptional regulators of FA metabolism (PPARα, RXRα, RXRβ and RXRγ) were up-regulated by QSG. As to glucose metabolism, QSG inhibited glycolytic activity by decreasing LDHA, while stimulated glucose oxidation by decreasing PDK4. Furthermore, QSG could facilitate tricarboxylic acid cycle, promote the transportation of ATP from mitochondria to cytoplasm and restore the mitochondrial function by increasing SUCLA2, CKMT2 and PGC-1α and decreasing UCP2 simultaneously. Conclusion: QSG improved myocardial energy metabolism through increasing FA metabolism,inhibiting uncoupling of glycolysis from glucose oxidation.

Aims: Cardiac lipotoxicity is the common consequence of lipid metabolism disorders in cardiomyocytes during development of heart failure (HF). Adenosine 5′monophosphate-activated protein kinase (AMPK) acts as an energy sensor and has a beneficial effect in reducing lipotoxicity. Notoginsenoside R1 (NGR1) is extracted from the traditional Chinese medicine Panax notoginseng (Burkill) F.H.Chen (P. notoginseng) and has definite cardioprotective effects. However, whether NGR1 can attenuate HF by mitigating lipotoxicity has not been elucidated yet. This study aimed to explore whether NGR1 plays a protective role against HF by ameliorating cardiac lipotoxicity via the AMPK pathway.Methods: In this study, HF mice model was established by left anterior descending (LAD) ligation. palmitic acid (PA) stimulated H9C2 cell model was applied to clarify the effects and potential mechanism of NGR1 on lipotoxicity. In vivo, NGR1 (7.14 mg/kg/days) and positive drug (simvastatin: 2.9 mg/kg/days) were orally administered for 14 days. Echocardiography was applied to assess heart functions. Lipid levels were measured by Enzyme-linked immunosorbent assay (ELISA) and key proteins in the AMPK pathway were detected by western blots. In vitro, NGR1 (40 μmol/L) or Compound C (an inhibitor of AMPK, 10 μmol/L) was co-cultured with PA stimulation for 24 h in H9C2 cells. CCK-8 assay was used to detect cell viability. Key lipotoxicity-related proteins were detected by western blots and the LipidTOX™ neutral lipid stains were used to assess lipid accumulation. In addition, Apoptosis was assessed by Hoechst/PI staining.Results: NGR1 could significantly improve the cardiac function and myocardial injury in mice with HF and up-regulate the expression of p-AMPK. Impressively, NGR1 inhibited the synthesis of diacylglycerol (DAG) and ceramide and promoted fatty acid oxidation (FAO) in vivo. Moreover, NGR1 significantly promoted expression of CPT-1A, the key enzyme in FAO pathway, and down-regulated the expression of GPAT and SPT, which were the key enzymes catalyzing production of DAG and ceramide. In vitro experiments showed that NGR1 could significantly attenuate lipid accumulation in PA-induced H9C2 cells and the Hoechst/PI staining results showed that NGR1 ameliorated lipotoxicity-induced apoptosis in PA-stimulated H9C2 cell model. Furthermore, co-treatment with inhibitor of AMPK abrogated the protective effects of NGR1. The regulative effects of NGR1 on lipid metabolism were also reversed by AMPK inhibitor.Conclusion: NGR1 could significantly improve the heart function of mice with HF and reduce cardiac lipotoxicity. The cardio-protective effects of NGR1 are mediated by the activation of AMPK pathway.