Heart failure (HF) leads to an increase in morbidity and mortality globally. Tanshinone IIA is an important traditional Chinese medicine monomer and has been shown to have remarkable protective effect against HF. Autophagy is critically involved in the progression of HF. The effect of Tanshinone IIA on autophagy has not been clarified yet. In this study, left anterior descending (LAD) ligation was used to induce HF model and a hydrogen peroxide-(H₂O₂-)-induced H9C2 cell injury model was established. in vivo, echocardiography results showed that Tanshinone IIA could significantly improve heart function. Western Blot result showed that Tanshinone IIA treatment enhanced autophagy and regulated expressions of key autophagy-related molecules, including protein 1 light chain 3 (LC3), p62 and Beclin1. Tanshinone IIA also inhibited apoptosis and regulated expressions of key apoptotic protein, including B cell lymphoma-2 (Bcl-2) and Bcl-2 Associated X Protein (Bax) and cleaved caspase-3 and -7. Further experiments demonstrated that the effects of Tanshinone IIA were mediated through upregulation of AMP-activated protein kinase (AMPK) and downregulation of mammalian target of rapamycin (mTOR) simultaneously. The mTOR agonist MHY1485 could abrogate the therapeutic effect of Tanshinone IIA in vitro. In conclusion, Tanshinone IIA protects cardiomyocytes and improves cardiac function by inhibiting apoptosis and inducing autophagy via activation of the AMPK-mTOR signaling pathway.

Rationale: Anthracycline-induced cardiotoxicity (AIC) is a major side effect that limits the use of anthracyclines as effective chemotherapeutics. No mechanism-based therapy is available when cardiac function deteriorates. Objective: We aim to elucidate the dynamic autophagic defects in AIC and to identify a mechanism-based therapy via both genetic and pharmacological studies. Method and Results: Through phenotyping an adult AIC zebrafish model, we detected a biphasic response in autophagy: activation in the early stage and suppression in the later phase that is characterized by a decline in cardiac function. We conducted conditional genetic studies with atg7 , which encodes a rate-limiting autophagy core protein, and found that atg7 overexpression leads to therapeutic effects in the late phase but deleterious effects in the early phase of adult AIC. We then assessed the therapeutic effects of 37 Food and Drug Administration–approved autophagy activators using an embryonic AIC zebrafish model and identified spironolactone, pravastatin, and minoxidil as top-ranking drugs. We demonstrated the therapeutic efficacy of these Food and Drug Administration–approved autophagy activators in the adult AIC model and confirmed that these drugs exert therapeutic effects in the late phase but not in the early AIC phase. Finally, we demonstrated that the time-dependent therapeutic effects are conserved in a mouse AIC model and that spironolactone and rapamycin activated autophagy in an Atg7-dependent fashion. Conclusions: Our findings suggest that atg7-based autophagy activation is an effective therapeutic avenue to reversing the decline in cardiac function in AIC, highlighting the time-dependent nature of autophagy-based therapy.

Heart failure (HF) represents a major public health burden. Inflammation has been shown to be a critical factor in the progression of HF, regardless of the aetiology. Disappointingly, the majority of clinical trials targeting aspects of inflammation in patients with HF have been largely negative. Many clinical researches demonstrate that danshen has a good efficacy on HF, and however, whether danshen exerts anti‐inflammatory effects against HF remains unclear. In our study, the employment of a water extracted and alcohol precipitated of danshen extract attenuated cardiac dysfunction and inflammation response in acute myocardial infarction‐induced HF rats. Transcriptome technique and validation results revealed that TLR4 signalling pathway was involved in the anti‐inflammation effects of danshen. In vitro, danshen reduced the release of inflammatory mediators in LPS‐stimulated RAW264.7 macrophage cells. Besides, the LPS‐stimulated macrophage conditioned media was applied to induce cardiac H9C2 cells injury, which could be attenuated by danshen. Furtherly, knock‐down and overexpression of TLR4 were utilized to confirm that danshen ameliorated inflammatory injury via MyD88‐dependent TLR4‐TRAF6‐NF‐κB signalling pathway in cardiomyocytes. Furthermore, by utilizing co‐immunoprecipitation, danshen was proved to suppress MD2/TLR4 complex formation and MyD88 recruitment. In conclusion, our results demonstrated that danshen ameliorates inflammatory injury by controlling MD2/TLR4‐MyD88 complex formation and TLR4‐TRAF6‐NF‐κB signalling pathway in acute myocardial infarction‐induced HF.

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.

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.