Cardiomyocyte-specific disruption of Cathepsin K protects against doxorubicin-induced cardiotoxicity

Nano-emulsion based on Santolina chamaecyparissus essential oil potentiates the cytotoxic and apoptotic effects of Doxorubicin: an in vitro study

AIM

This study was aimed at investigating the cytotoxic effect of a novel combination of doxorubicin (DOX) and nano-formulation of Santolina chamaecyparissus L. essential oil (SCEO-NANO) on hepatic (HepG2) and colon (HT29) cancer cell lines.

METHODS

A nano-emulsion was prepared by high-pressure homogenisation, then analysed by zetasizer and Fourier transform infrared spectroscopy. HepG2 and HT29 cells were used in in vitro tests for apoptosis detection.

RESULTS

Formulated droplet size increased in DOX@SCEO-NANO/DOX to 11.54 ± 0.02 with uniform distribution (PDI = 0.13 ± 0.01), when compared with SCEO-NANO (size: 8.91 ± 0.02 nm; PDI = 0.1 ± 0.02). In both cells, DOX@SCEO-NANO/DOX led to a considerable reduction in colony formation. Compared to DOX, apoprotein proteins were overexpressed in HepG2 cells, showing increases of 8.66-fold for caspase-3 and 4.24-fold for the Bax/Bcl-2 ratio. In HT29 cells, ROS-dependent necrosis and apoptosis were seen. Comparing DOX@SCEO-NANO/DOX versus DOX, greater levels of caspase-3 and the Bax/Bcl-2 ratio were observed.

CONCLUSION

The DOX@SCEO-NANO/DOX formulation showed potential for targeted eradication of colon adenocarcinoma and hepatocellular carcinoma cells.

Aerobic Exercise Attenuates Doxorubicin-Induced Cardiomyopathy by Suppressing NLRP3 Inflammasome Activation in a Rat Model

Doxorubicin (DOX) is a potent chemotherapeutic agent with well-documented dose-dependent cardiotoxicity. Regular exercise is recognized for its cardioprotective effects against DOX-induced cardiac inflammation, although the precise mechanisms remain incompletely understood. The activation of inflammasomes has been implicated in the pathogenesis and treatment of DOX-induced cardiotoxicity, with the nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome emerging as a key mediator in cardiovascular inflammation. This study aimed to investigate the role of exercise in modulating the NLRP3 inflammasome to protect against DOX-induced cardiac inflammation. Male Sprague-Dawley rats were randomly assigned to receive a 10-day course of DOX or saline injections, with or without a preceding 10-week treadmill running regimen. Cardiovascular function and histological changes were subsequently evaluated. DOX-induced cardiotoxicity was characterized by cardiac atrophy, systolic dysfunction, and hypotension, alongside activation of the NLRP3 inflammasome. Our findings revealed that regular exercise preserved cardiac mass and hypertrophic indices and prevented DOX-induced cardiac dysfunction, although it did not fully preserve blood pressure. These results underscore the significant cardioprotective effects of exercise against DOX-induced cardiotoxicity. While regular exercise did not entirely prevent DOX-induced hypotension, our findings demonstrate that it confers protection against DOX-induced cardiotoxicity by suppressing NLRP3 inflammasome activation in the heart, underscoring its anti-inflammatory role. Further research should explore the temporal dynamics and interactions among exercise, pyroptosis, and other pathways in DOX-induced cardiotoxicity to enhance translational applications in cardiovascular medicine.

Diversifying the anthracycline class of anti-cancer drugs identifies aclarubicin for superior survival of acute myeloid leukemia patients

The efficacy of anthracycline-based chemotherapeutics, which include doxorubicin and its structural relatives daunorubicin and idarubicin, remains almost unmatched in oncology, despite a side effect profile including cumulative dose-dependent cardiotoxicity, therapy-related malignancies and infertility. Detoxifying anthracyclines while preserving their anti-neoplastic effects is arguably a major unmet need in modern oncology, as cardiovascular complications that limit anti-cancer treatment are a leading cause of morbidity and mortality among the 17 million cancer survivors in the U.S. In this study, we examined different clinically relevant anthracycline drugs for a series of features including mode of action (chromatin and DNA damage), bio-distribution, anti-tumor efficacy and cardiotoxicity in pre-clinical models and patients. The different anthracycline drugs have surprisingly individual efficacy and toxicity profiles. In particular, aclarubicin stands out in pre-clinical models and clinical studies, as it potently kills cancer cells, lacks cardiotoxicity, and can be safely administered even after the maximum cumulative dose of either doxorubicin or idarubicin has been reached. Retrospective analysis of aclarubicin used as second-line treatment for relapsed/refractory AML patients showed survival effects similar to its use in first line, leading to a notable 23% increase in 5-year overall survival compared to other intensive chemotherapies. Considering individual anthracyclines as distinct entities unveils new treatment options, such as the identification of aclarubicin, which significantly improves the survival outcomes of AML patients while mitigating the treatment-limiting side-effects. Building upon these findings, an international multicenter Phase III prospective study is prepared, to integrate aclarubicin into the treatment of relapsed/refractory AML patients.

Uncovering the Cardioprotective Potential of Diacerein in Doxorubicin Cardiotoxicity: Mitigating Ferritinophagy-Mediated Ferroptosis via Upregulating NRF2/SLC7A11/GPX4 Axis

Doxorubicin (DOX)-induced cardiotoxicity (DIC) is a life-threatening clinical issue with limited preventive approaches, posing a substantial challenge to cancer survivors. The anthraquinone diacerein (DCN) exhibits significant anti-inflammatory, anti-proliferative, and antioxidant actions. Its beneficial effects on DIC have yet to be clarified. Therefore, this study investigated DCN's cardioprotective potency and its conceivable molecular targets against DIC. Twenty-eight Wister rats were assigned to CON, DOX, DCN-L/DOX, and DCN-H/DOX groups. Serum cardiac damage indices, iron assay, oxidative stress, inflammation, endoplasmic reticulum (ER) stress, apoptosis, ferritinophagy, and ferroptosis-related biomarkers were estimated. Nuclear factor E2-related factor 2 (NRF2) DNA-binding activity and phospho-p53 immunoreactivity were assessed. DCN administration effectively ameliorated DOX-induced cardiac cytomorphological abnormalities. Additionally, DCN profoundly combated the DOX-induced labile iron pool expansion alongside its consequent lethal lipid peroxide overproduction, whereas it counteracted ferritinophagy and enhanced iron storage. Indeed, DCN valuably reinforced the cardiomyocytes' resistance to ferroptosis, mainly by restoring the NRF2/solute carrier family 7 member 11 (SLC7A11)/glutathione peroxidase 4 (GPX4) signaling axis. Furthermore, DCN abrogated the cardiac oxidative damage, inflammatory response, ER stress, and cardiomyocyte apoptosis elicited by DOX. In conclusion, for the first time, our findings validated DCN's cardioprotective potency against DIC based on its antioxidant, anti-inflammatory, anti-ferroptotic, and anti-apoptotic imprint, chiefly mediated by the NRF2/SLC7A11/GPX4 axis. Accordingly, DCN could represent a promising therapeutic avenue for patients under DOX-dependent chemotherapy.

Comparative analysis of ventricular stiffness across species

Investigating ventricular diastolic properties is crucial for understanding the physiological cardiac functions in organisms and unraveling the pathological mechanisms of cardiovascular disorders. Ventricular stiffness, a fundamental parameter that defines ventricular diastolic functions in chordates, is typically analyzed using the end-diastolic pressure-volume relationship (EDPVR). However, comparing ventricular stiffness accurately across chambers of varying maximum volume capacities has been a long-standing challenge. As one of the solutions to this problem, we propose calculating a relative ventricular stiffness index by applying an exponential approximation formula to the EDPVR plot data of the relationship between ventricular pressure and values of normalized ventricular volume by the ventricular weight. This article reviews the potential, utility, and limitations of using normalized EDPVR analysis in recent studies. Herein, we measured and ranked ventricular stiffness in differently sized and shaped chambers using ex vivo ventricular pressure-volume analysis data from four animals: Wistar rats, red-eared slider turtles, masu salmon, and cherry salmon. Furthermore, we have discussed the mechanical effects of intracellular and extracellular viscoelastic components, Titin (Connectin) filaments, collagens, physiological sarcomere length, and other factors that govern ventricular stiffness. Our review provides insights into the comparison of ventricular stiffness in different-sized ventricles between heterologous and homologous species, including non-model organisms.

Astragaloside IV Alleviates Doxorubicin-Induced Cardiotoxicity by Inhibiting Cardiomyocyte Pyroptosis through the SIRT1/NLRP3 Pathway

Doxorubicin (DOX) is a powerful anthracycline antineoplastic drug used to treat a wide spectrum of tumors. However, its clinical application is limited due to cardiotoxic side effects. Astragaloside IV (AS IV), one of the major compounds present in aqueous extracts of Astragalus membranaceus, possesses potent cardiovascular protective properties, but the underlying molecular mechanisms are unclear. Thus, the aim of this study was to investigate the effect of AS IV on DOX-induced cardiotoxicity (DIC). Our findings revealed that DOX induced pyroptosis through the caspase-1/gasdermin D (GSDMD) and caspase-3/gasdermin E (GSDME) pathways. AS IV treatment significantly improved the cardiac function and alleviated myocardial injury in DOX-exposed mice by regulating intestinal flora and inhibiting pyroptosis; markedly suppressed the levels of cleaved caspase-1, N-GSDMD, cleaved caspase-3, and N-GSDME; and reversed DOX-induced downregulation of silent information regulator 1 (SIRT1) and activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome in mice. The SIRT1 inhibitor EX527 significantly blocked the protective effects of AS IV. Collectively, our results suggest that AS IV protects against DIC by inhibiting pyroptosis through the SIRT1/NLRP3 pathway.

Molecular hydrogen attenuates sepsis-induced cardiomyopathy in mice by promoting autophagy

BACKGROUND

Approximately 40 to 60% of patients with sepsis develop sepsis-induced cardiomyopathy (SIC), which is associated with a substantial increase in mortality. We have found that molecular hydrogen (H2) inhalation improved the survival rate and cardiac injury in septic mice. However, the mechanism remains unclear. This study aimed to explore the regulatory mechanism by which hydrogen modulates autophagy and its role in hydrogen protection of SIC.

METHODS

Cecal ligation and puncture (CLP) was used to induce sepsis in adult C57BL/6J male mice. The mice were randomly divided into 4 groups: Sham, Sham + 2% hydrogen inhalation (H2), CLP, and CLP + H2 group. The 7-day survival rate was recorded. Myocardial pathological scores were calculated. Myocardial troponin I (cTnI) levels in serum were detected, and the levels of autophagy- and mitophagy-related proteins in myocardial tissue were measured. Another four groups of mice were also studied: CLP, CLP + Bafilomycin A1 (BafA1), CLP + H2, and CLP + H2 + BafA1 group. Mice in the BafA1 group received an intraperitoneal injection of the autophagy inhibitor BafA1 1 mg/kg 1 h after operation. The detection indicators remained the same as before.

RESULTS

The survival rate of septic mice treated with H2 was significantly improved, myocardial tissue inflammation was improved, serum cTnI level was decreased, autophagy flux was increased, and mitophagy protein content was decreased (P < 0.05). Compared to the CLP + H2 group, the CLP + H2 + BafA1 group showed a decrease in autophagy level and 7-day survival rate, an increase in myocardial tissue injury and cTnI level, which reversed the protective effect of hydrogen (P < 0.05).

CONCLUSION

Hydrogen exerts protective effect against SIC, which may be achieved through the promotion of autophagy and mitophagy.

Boesenbergia rotunda displayed anti-inflammatory, antioxidant and anti-apoptotic efficacy in doxorubicin-induced cardiotoxicity in rats

This study evaluated the cardioprotective properties of Boesenbergia rotunda extract (BrE) against doxorubicin (DOX) induced cardiotoxicity. Rats received oral gavage of BrE for 28 days and DOX (5 mg/kg/week for 3 weeks). Thereafter the animals were sacrificed, blood and cardiac samples were collected for biochemical, histological and immunohistochemical analyses. The results indicated that BrE attenuated DOX triggered body and cardiac weight loss and prevented against cardiac injury by mitigating histopathological alterations in cardiac tissues as well as serum cardiac function enzymes. BrE significantly reduced serum levels of aspartate transaminase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), troponin T (TnT) and creatine kinase-MB (CK-MB) in DOX-treated rats. Furthermore, BrE alleviated cardiotoxicity by reducing DOX instigated oxidative stress and potentiating the level of glutathione, as well as the activities superoxide dismutase and catalase in cardiac tissues. In addition, BrE significantly decreased the characteristic indices of DOX-induced cardiac inflammation and apoptosis. Immuno-histochemical analysis revealed that BrE decreased the stain intensity of p53 and myeloperoxidase (MPO) proteins compared to the DXB alone group. In conclusion, our results indicated that BrE modulated oxidative stress, inflammation and apoptosis to attenuate DOX-induced cardiac damage.

Cardioprotective effects of minocycline against doxorubicin-induced cardiotoxicity

BACKGROUND

Doxorubicin (Dox)-induced cardiotoxicity has limited its use. Inflammation, oxidative stress, and apoptosis have important roles in Dox-induced cardiotoxicity. Minocycline (Min) is an antibiotic with anti-inflammatory, anti-oxidant and anti-apoptotic properties. Here, the cardioprotective effects of Min against Dox-induced cardiotoxicity in adult male rats were evaluated.

METHODS

Forty-two adult male rats were divided into six groups including control group (normal saline), Dox group, Min groups (Min 45 mg/kg and Min 90 mg/kg), and treatment groups (Dox + Min 45 mg/kg and Dox + Min 90 mg/kg). Dox (2.5 mg/kg) was administered three times a week for two weeks, and Min once a day for three weeks via intraperitoneal route. Cardiac tissue sections were stained with hematoxylin and eosin for histological examination. The activities of lactate dehydrogenase (LDH) and creatine kinase MB (CK-MB) in serum as well as the activity of catalase and superoxide dismutase (SOD) in cardiac tissue were measured. Cardiac tissue levels of malondialdehyde (MDA), TNF-α, and IL-1β were also measured using ELISA.

RESULTS

Compared with the Dox group, treatment with Min significantly decreased the activity of LDH and CK-MB. Min also increased the activity of catalase and SOD in the tissue samples. The results showed that the levels of MDA, TNF-α, and IL-1β in cardiac tissue samples were significantly lower in the Min groups compared with the Dox group. In addition, histopathological results showed that Min reduced the tissue damage caused by Dox.

CONCLUSION

Min reduced Dox-induced cardiotoxicity. The anti-oxidant and anti-inflammatory properties of Min may contribute to its protective effects.

Serum and glucocorticoid inducible kinase 1 modulates mitochondrial dysfunction and oxidative stress in doxorubicin-induced cardiomyocytes by regulating Hippo pathway via Neural precursor cell-expressed developmentally down-regulated 4 type 2

Doxorubicin (Dox) was reported to cause mitochondrial dysfunction and oxidative stress in cardiomyocytes, leading to cardiomyocyte apoptosis and ultimately heart failure. Serum and glucocorticoid inducible kinase 1 (SGK1) participates in the progression of various cardiovascular diseases. Thus, we aimed to explore the role and regulatory mechanism of SGK1 in Dox-induced cardiomyocyte injury. The expression of SGK1 was evaluated in blood samples of heart failure children, and in myocardial tissues and blood samples of Dox-induced rats. Subsequently, we treated cardiomyocytes with Dox in vitro. A gain-of-function assay was performed to assess the effects of SGK1 on mitochondrial dysfunction and oxidative stress in Dox-induced cardiomyocytes. Furthermore, the modulation of SGK1 on Neural precursor cell-expressed developmentally down-regulated 4 type 2 (NEDD4-2) expression and the subsequent Hippo pathway was validated. In our study, we found that SGK1 was downregulated in blood samples of heart failure children, as well as myocardial tissues and blood samples of Dox-induced rats. SGK1 overexpression alleviated the decreases of mitochondrial complex activity, mitochondrial membrane potential, adenosine triphosphate (ATP) content and ATP synthetase activity stimulated by Dox. Besides, SGK1 overexpression reversed the promoting effects of Dox on oxidative stress and apoptosis. Mechanistically, SGK1 overexpression inhibited the expression of NEDD4-2 and blocked the subsequent activation of Hippo pathway. NEDD4-2 overexpression or activation of Hippo reversed the protective effects of SGK1 overexpression on Dox-induced cardiomyocyte injury. In conclusion, our results revealed that SGK1 modulated mitochondrial dysfunction and oxidative stress in Dox-induced cardiomyocytes by regulating Hippo pathway via NEDD4-2.

Synergistic cardioprotective effects of melatonin and deferoxamine through the improvement of ferritinophagy in doxorubicin-induced acute cardiotoxicity

Ferritinophagy is one of the most recent molecular mechanisms affecting cardiac function. In addition, it is one of the pathways by which doxorubicin, one of the anticancer drugs commonly used, negatively impacts the cardiac muscle, leading to cardiac function impairment. This side effect limits the use of doxorubicin. Iron chelators play an important role in hindering ferritinophagy. Antioxidants can also impact ferritinophagy by improving oxidative stress. In this study, it was assumed that the antioxidant function of melatonin could promote the action of deferoxamine, an iron chelator, at the level of ferritinophagy. A total of 42 male Wistar rats (150-200 g) were divided into seven groups (n = 6) which consisted of group I: control normal, group II: doxorubicin (Dox), group III: melatonin (Mel), group IV: deferoxamine (Des), group V: Mel + Dox, group VI: Des + Dox, and group VII: Mel + Des + Dox. Groups III, V and VII were orally pretreated with melatonin 20 mg/kg/day for 7 days. Groups IV, VI and VII were treated with deferoxamine at a 250 mg/kg/dose once on D4 before Dox was given. Doxorubicin was given at a 20 mg/kg ip single dose. On the 8th day, the rats were lightly anaesthetized for electrocardiography analysis and echocardiography. Serum samples were collected and then sacrificed for tissue sampling. The following biochemical assessments were carried out: PCR of NCOA4, IREB2, FTH1, SLC7A11, and GPX4; and ELISA for serum cTnI, serum transferrin, tissue GSH, and malondialdehyde. In addition, histopathological assessment of heart injury; immunostaining of caspase-3, Bax, and Bcl2; and physiological function assessment by ECG and ECHO were carried out. Doxorubicin-induced acute significant cardiac injury with increased ferritinophagy and apoptosis responded to single and combined prophylactic treatment, in which the combined treatment showed mostly the best results. In conclusion, using melatonin as an antioxidant with an iron chelator, deferoxamine, could hinder the hazardous cardiotoxic effect of doxorubicin. However, further studies are needed to detect the impact of higher doses of melatonin and deferoxamine with a prolonged treatment period.

Inhibition of myocardial cathepsin-L release during reperfusion following myocardial infarction improves cardiac function and reduces infarct size

AIMS

Identifying novel mediators of lethal myocardial reperfusion injury that can be targeted during primary percutaneous coronary intervention (PPCI) is key to limiting the progression of patients with ST-elevation myocardial infarction (STEMI) to heart failure. Here, we show through parallel clinical and integrative preclinical studies the significance of the protease cathepsin-L on cardiac function during reperfusion injury.

METHODS AND RESULTS

We found that direct cardiac release of cathepsin-L in STEMI patients (n = 76) immediately post-PPCI leads to elevated serum cathepsin-L levels and that serum levels of cathepsin-L in the first 24 h post-reperfusion are associated with reduced cardiac contractile function and increased infarct size. Preclinical studies demonstrate that inhibition of cathepsin-L release following reperfusion injury with CAA0225 reduces infarct size and improves cardiac contractile function by limiting abnormal cardiomyocyte calcium handling and apoptosis.

CONCLUSION

Our findings suggest that cathepsin-L is a novel therapeutic target that could be exploited clinically to counteract the deleterious effects of acute reperfusion injury after an acute STEMI.

Cathepsin K activity controls cachexia-induced muscle atrophy via the modulation of IRS1 ubiquitination

BACKGROUND

Cachexia is a complicated metabolic disorder that is characterize by progressive atrophy of skeletal muscle. Cathepsin K (CTSK) is a widely expressed cysteine protease that has garnered attention because of its enzymatic and non-enzymatic functions in signalling in various pathological conditions. Here, we examined whether CTSK participates in cancer-induced skeletal muscle loss and dysfunction, focusing on protein metabolic imbalance.

METHODS

Male 9-week-old wild-type (CTSK^+/+ , n = 10) and CTSK-knockout (CTSK^-/- , n = 10) mice were injected subcutaneously with Lewis lung carcinoma cells (LLC; 5 × 10⁵ ) or saline, respectively. The mice were then subjected to muscle mass and muscle function measurements. HE staining, immunostaining, quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and western blotting were used to explore the CTSK expression and IRS1/Akt pathway in the gastrocnemius muscle at various time points. In vitro measurements included CTSK expression, IRS1/Akt pathway-related target molecule expressions, and the diameter of C2C12 myotubes with or without LLC-conditioned medium (LCM). An IRS1 ubiquitin assay, and truncation, co-immunoprecipitation, and co-localization experiments were also performed.

RESULTS

CTSK^+/+ cachectic animals exhibited loss of skeletal muscle mass (muscle weight loss of 15%, n = 10, P < 0.01), muscle dysfunction (grip strength loss > 15%, n = 10, P < 0.01), and fibre area (average area reduction > 30%, n = 5, P < 0.01). Compared with that of non-cachectic CTSK^+/+ mice, the skeletal muscle of cachectic CTSK^+/+ mice exhibited greater degradation of insulin receptor substrate 1 (IRS1, P < 0.01). In this setting, cachectic muscles exhibited decreases in the phosphorylation levels of protein kinase B (Akt³⁰⁸ , P < 0.01; Akt⁴⁷³ , P < 0.05) and anabolic-related proteins (the mammalian target of rapamycin, P < 0.01) and increased levels of catabolism-related proteins (muscle RING-finger protein-1, P < 0.01; MAFbx1, P < 0.01) in CTSK^+/+ mice (n = 3). Although there was no difference in LLC tumour growth (n = 10, P = 0.44), CTSK deletion mitigated the IRS1 degradation, loss of the skeletal muscle mass (n = 10, P < 0.01), and dysfunction (n = 10, P < 0.01). In vitro, CTSK silencing prevented the IRS1 ubiquitination and loss of the myotube myosin heavy chain content (P < 0.01) induced by LCM, and these changes were accelerated by CTSK overexpression even without LCM. Immunoprecipitation showed that CTSK selectively acted on IRS1 in the region of amino acids 268 to 574. The results of co-transfection of IRS1-N-FLAG or IRS1-C-FLAG with CTSK suggested that CTSK selectively cleaves IRS1 and causes ubiquitination-related degradation of IRS1.

CONCLUSIONS

These results demonstrate that CTSK plays a novel role in IRS1 ubiquitination in LLC-induced muscle wasting, and suggest that CTSK could be an effective therapeutic target for cancer-related cachexia.

Identification and Analysis of Hub Genes in Diabetic Cardiomyopathy: Potential Role of Cytochrome P450 1A1 in Mitochondrial Metabolism and STZ-Induced Myocardial Dysfunction

Diabetic cardiomyopathy (DCM) is a primary cause of death in diabetic patients; however, its molecular mechanism is not yet clear, and there is no uniform standard for diagnosis. The aim of this study is to discover the pathogenesis and potential therapeutic targets of DCM through screening and analysis of differentially expressed genes (DEGs) in heart ventricles of DCM, and to testify the role of key hub genes in DCM-induced myocardial dysfunction. Datasets GSE4745 and GSE6880 were downloaded from the GEO database. The difference analysis, visual analysis, cluster analysis and enrichment analysis were performed by using R language, python scripts and bioinformatics software followed by the construction of protein-protein interaction (PPI) network to obtain hub genes. The DCM models were established by streptozocin (STZ) injection to the male mice. The cardiac function and the expressions of hub genes were examined by using echocardiography and real-time quantitative poly-merase chain reaction (RT-qPCR), followed by multiple statistical analyses. Bioinformatic results indicate that mitochondrial dysfunction, disturbed lipid metabolism and decreased collagen synthesis are the main causes of the DCM development. In particular, the hub gene Cyp1a1 that encodes Cytochrome P450 1A1 (CYP4501A1) enzyme has the highest connectivity in the interaction network, and is associated with mitochondrial homeostasis and energy metabolism. It plays a critical role in the oxidation of endogenous or exogenous substrates. Our RT-qPCR results confirmed that ventricular Cyp1a1 mRNA level was nearly 12-fold upregulated in DCM model compared to normal control, which was correlated with abnormal cardiac function in diabetic individuals. CYP4501A1 protein expression in mitochondria was also increased in diabetic hearts. However, we found no significant changes in collagen expressions in cardiac ventricles of mice with DCM. This study provided compact data support for understanding the pathogenesis of DCM. CYP4501A1 might be considered as a potential candidate targeting for DCM therapy. Follow-up animal and clinical verifications need to be further explored.

The regulatory mechanism between lysosomes and mitochondria in the aetiology of cardiovascular diseases

Coordinated action among various organelles maintains cellular functions. For instance, mitochondria and lysosomes are the main organelles contributing to cellular metabolism and provide energy for cardiomyocyte contraction. They also provide essential signalling platforms in the cell that regulate many key processes such as autophagy, apoptosis, oxidative stress, inflammation and cell death. Often, abnormalities in mitochondrial or lysosomal structures and functions bring about cardiovascular diseases (CVDs). Although the communication between mitochondria and lysosomes throughout the cardiovascular system is intensely studied, the regulatory mechanisms have not been completely understood. Thus, we summarize the most recent studies related to mitochondria and lysosomes' role in CVDs and their potential connections and communications under cardiac pathophysiological conditions. Further, we discuss limitations and future perspectives regarding diagnosis, therapeutic strategies and drug discovery in CVDs.

Cardioprotective effects of corilagin on doxorubicin induced cardiotoxicity via P13K/Akt and NF-κB signaling pathways in rats model

Even though doxorubicin (DOX) is a potential chemotherapeutic drug, its usage is restricted due to its ability to induce cardiac damage. In order to prevent this damage, a potent cardioprotective agent should be associated with DOX treatment. Corilagin is a natural polyphenol tannic acid which unveils enormous pharmacological activities predominantly as an antitumor agent. Hence, the current work is designed to study the precise mechanisms of corilagin upon administration in doxorubicin induced cardiotoxicity in experimental rats. DOX treated rats showed diminished level of blood pressures and heart rate, whereas corilagin along with DOX treatment improved the status. Cardiotoxicity enzymes and biomarkers were found to be increased in the serum of DOX induced rats. Upon treatment, corilagin could reduce the cardiotoxicity enzymes and biomarkers in serum. Histopathological examination of cardiac tissue also revealed the anti-toxic effects of corilagin in contrast to DOX. Injection of DOX in rats showed inflammatory cells infiltration, necrosis and fragmented myofibrils. Corilagin treatment reverted the cardiac histology to near normal. Inflammatory mediators and P13K, Akt, and NF-κB were upregulated in DOX administered rats. Corilagin repressed the levels of P13K, Akt, and NF-κB in DOX induced rats. In the present investigations, corilagin improved cardiac function via reducing injury, inflammation and promoting apoptosis thereby suggesting that corilagin would be recommended for DOX-induced cardiotoxicity.

A comprehensive review on time-tested anticancer drug doxorubicin

Doxorubicin or Adriamycin, is one of the most widely used chemotherapeutic drug for treating a myriad of cancers. It induces cell death through multiple intracellular targets: reactive oxygen species generation, DNA-adduct formation, topoisomerase II inhibition, histone eviction, Ca²⁺ and iron hemostasis regulation, and ceramide overproduction. Moreover, doxorubicin-treated dying cells undergo cellular modifications that enable neighboring dendritic cell activation and enhanced presentation of tumor antigen. In addition, doxorubicin also aids in the immune-mediated clearance of tumor cells. However, the development of chemoresistance and cardiotoxicity side effect has undermined its widespread applicability. Several formulations of doxorubicin and co-treatments with inhibitors, miRNAs, natural compounds and other chemotherapeutic drugs have been essential in reducing its dosage-dependent toxicity and combating the development of resistance. Further, more advanced research into the molecular mechanism of chemoresistance development would be vital in improving the overall survivability of clinical patients and in preventing cancer relapse.

Signalling pathways linking cysteine cathepsins to adverse cardiac remodelling

Adverse cardiac remodelling clinically manifests as deleterious changes to heart architecture (size, mass and geometry) and function. These changes, which include alterations to ventricular wall thickness, chamber dilation and poor contractility, are important because they progressively drive patients with cardiac disease towards heart failure and are associated with poor prognosis. Cysteine cathepsins contribute to key signalling pathways involved in adverse cardiac remodelling including synthesis and degradation of the cardiac extracellular matrix (ECM), cardiomyocyte hypertrophy, impaired cardiomyocyte contractility and apoptosis. In this review, we highlight the role of cathepsins in these signalling pathways as well as their translational potential as therapeutic targets in cardiac disease.

Ethanol Extract of Chinese Hawthorn (Crataegus pinnatifida) Fruit Reduces Inflammation and Oxidative Stress in Rats with Doxorubicin-Induced Chronic Heart Failure

Background

Chinese hawthorn (Crataegus pinnatifida) fruit is a traditional Chinese medicine for treatment of digestive system and cardiovascular diseases. The fruit contains polyphenol compounds, such as epicatechin, that have anti-inflammatory activity. This study aimed to investigate the effects of an alcohol extract of hawthorn fruit (HAE) on inflammation and oxidative stress in rats with doxorubicin-induced chronic heart failure (CHF).

Material/Methods

Rats were intraperitoneally injected with doxorubicin to induce CHF and subsequently treated with HAE intragastrically once daily for 6 weeks. At the end of the experiment, echocardiographic and hemodynamic parameters were assessed, and enzyme-linked immunoassays were used to detect the levels of cardiac injury markers (brain natriuretic peptide, creatine kinase-MB, aspartate aminotransferase, lactate dehydrogenase, copeptin, and adrenomedullin), oxidative stress markers (glutathione peroxidase and malondialdehyde), and inflammatory cytokines (interleukin [IL]-6, IL-8, IL-1β, and tumor necrosis factor-α). The IL-1β, IL-6, glutathione peroxidase-1, and catalase mRNA levels were also measured by quantitative real-time polymerase chain reaction.

Results

Our findings indicated that HAE exerts a cardioprotective effect, as shown by improved echocardiographic and hemodynamic parameters, decreased activity of serum myocardial enzymes, reduced serum levels of CHF markers, and inhibited inflammatory response in cardiac tissue. In addition, HAE treatment downregulated the mRNA expression of IL-1β and tumor necrosis factor-α and upregulated the mRNA expression of glutathione peroxidase-1 and catalase compared with untreated doxorubicin-induced CHF rats.

Conclusions

HAE shows promise for the prevention and treatment of CHF. The cardioprotective effect of HAE appears to be related to inhibition of both the inflammatory response and oxidative stress in vivo.

A short review: Doxorubicin and its effect on cardiac proteins

Doxorubicin (DOX) is a boon for cancer-suffering patients. However, the undesirable effect on health on vital organs, especially the heart, is a limiting factor, resulting in an increased number of patients with cardiac dysfunction. The present review focuses on the contractile machinery and associated factors, which get affected due to DOX toxicity in chemo-patients for which they are kept under life-long investigation for cardiac function. DOX-induced oxidative stress disrupts the integrity of cardiac contractile muscle proteins that alter the rhythmic mechanism and oxygen consumption rate of the heart. DOX is an oxidant and it is further discussed that oxidative stress prompts the damage of contractile components and associated factors, which include Ca²⁺ load through Ca²⁺ ATPase, SERCA, ryanodine receptor-2, phospholamban, and calsequestrin, which ultimately results in left ventricular ejection and dilation. Based on data and evidence, the associated proteins can be considered as clinical markers to develop medications for patients. Even with the advancement of various diagnosing tools and modified drugs to mitigate DOX-induced cardiotoxicity, the risk could not be surmounted with survivors of cancer.

Weighted correlation network bioinformatics uncovers a key molecular biosignature driving the left-sided heart failure

BACKGROUND

Left-sided heart failure (HF) is documented as a key prognostic factor in HF. However, the relative molecular mechanisms underlying left-sided HF is unknown. The purpose of this study is to unearth significant modules, pivotal genes and candidate regulatory components governing the progression of left-sided HF by bioinformatical analysis.

METHODS

A total of 319 samples in GSE57345 dataset were used for weighted gene correlation network analysis (WGCNA). ClusterProfiler package in R was used to conduct functional enrichment for genes uncovered from the modules of interest. Regulatory networks of genes were built using Cytoscape while Enrichr database was used for identification of transcription factors (TFs). The MCODE plugin was used for identifying hub genes in the modules of interest and their validation was performed based on GSE1869 dataset.

RESULTS

A total of six significant modules were identified. Notably, the blue module was confirmed as the most crucially associated with left-sided HF, ischemic heart disease (ISCH) and dilated cardiomyopathy (CMP). Functional enrichment conveyed that genes belonging to this module were mainly those driving the extracellular matrix-associated processes such as extracellular matrix structural constituent and collagen binding. A total of seven transcriptional factors, including Suppressor of Zeste 12 Protein Homolog (SUZ12) and nuclear factor erythroid 2 like 2 (NFE2L2), adrenergic receptor (AR), were identified as possible regulators of coexpression genes identified in the blue module. A total of three key genes (OGN, HTRA1 and MXRA5) were retained after validation of their prognostic value in left-sided HF. The results of functional enrichment confirmed that these key genes were primarily involved in response to transforming growth factor beta and extracellular matrix.

CONCLUSION

We uncovered a candidate gene signature correlated with HF, ISCH and CMP in the left ventricle, which may help provide better prognosis and therapeutic decisions and in HF, ISCH and CMP patients.

Mitophagy inhibitor liensinine suppresses doxorubicin-induced cardiotoxicity through inhibition of Drp1-mediated maladaptive mitochondrial fission

Doxorubicin (DOX) is one of the most effective antineoplastic drugs. However, its clinical application has been greatly limited due to the development of cardiotoxicity with DOX utilization. A number of theories have been postulated for DOX-induced cardiotoxicity with a pivotal contribution from unchecked (excess) mitophagy and mitochondrial fission. Liensinine (LIEN), a newly identified mitophagy inhibitor, strengthens the antineoplastic efficacy of DOX although its action on hearts remains elusive. This study was designed to examine the effect of LIEN on DOX-induced cardiotoxicity and the underlying mechanisms involved with a focus on mitochondrial dynamics. Our data revealed that LIEN alleviated DOX-induced cardiac dysfunction and apoptosis through inhibition of dynamin-related protein 1 (Drp1)-mediated excess (unchecked) mitochondrial fission. LIEN treatment decreased Drp1 phosphorylation at Ser⁶¹⁶ site, inhibited mitochondrial fragmentation, mitophagy (assessed by TOM20 and TIM23), oxidative stress, cytochrome C leakage, cardiomyocyte apoptosis, as well as improved mitochondrial function and cardiomyocyte contractile function in DOX-induced cardiac injury. In DOX-challenged neonatal mouse ventricular myocytes (NMVMs), LIEN-suppressed Drp1 phosphorylation, mitochondrial fragmentation, and apoptosis were blunted by Rab7 overexpression, the effect of which was reversed by the ERK inhibitor U0126. Moreover, activation of ERK or Drp1 abolished the protective effects of LIEN on cardiomyocyte mechanical anomalies. These data shed some lights towards understanding the role of LIEN as a new protective agent against DOX-associated cardiotoxicity without compromising its anti-tumor effects.

The Effects of Inhibition of MicroRNA-375 in a Mouse Model of Doxorubicin-Induced Cardiac Toxicity

BACKGROUND Doxorubicin-induced myocardial toxicity is associated with oxidative stress, cardiomyocyte, apoptosis, and loss of contractile function. Previous studies showed that microRNA-375 (miR-375) expression was increased in mouse models of heart failure and clinically, and that inhibition of miR-375 reduced inflammation and increased survival of cardiomyocytes. This study aimed to investigate the effects and mechanisms of inhibition of miR-375 in a mouse model of doxorubicin-induced cardiac toxicity in vivo and in doxorubicin-treated rat and mouse cardiomyocytes in vitro. MATERIAL AND METHODS The mouse model of doxorubicin-induced cardiac toxicity was developed using an intraperitoneal injection of doxorubicin (15 mg/kg diluted in 0.9% saline) for eight days. Treatment was followed by a single subcutaneous injection of miR-375 inhibitor. H9c2 rat cardiac myocytes and adult murine cardiomyocytes (AMCs) were cultured in vitro and treated with doxorubicin, with and without pretreatment with miR-375 inhibitor. RESULTS Doxorubicin significantly upregulated miR-375 expression in vitro and in vivo, and inhibition of miR-375 re-established myocardial redox homeostasis, prevented doxorubicin-induced oxidative stress and cardiomyocyte apoptosis, and activated the PDK1/AKT axis by reducing the direct binding of miR-375 to 3' UTR of the PDK1 gene. Inhibition of PDK1 and AKT abolished the protective role of miR-375 inhibition on doxorubicin-induced oxidative damage. CONCLUSIONS Inhibition of miR-375 prevented oxidative damage in a mouse model of doxorubicin-induced cardiac toxicity in vivo and in doxorubicin-treated rat and mouse cardiomyocytes in vitro through the PDK1/AKT signaling pathway.

Luteolin Attenuates Doxorubicin-Induced Cardiotoxicity Through Promoting Mitochondrial Autophagy

Doxorubicin is a valuable antineoplastic drug although its clinical use is greatly hindered by its severe cardiotoxicity with dismal target therapy available. Luteolin is a natural product extracted from vegetables and fruits with a wide range of biological efficacies including anti-oxidative, anti-tumorigenic, and anti-inflammatory properties. This study was designed to examine the possible effect of luteolin on doxorubicin-induced cardiotoxicity, if any, and the mechanism(s) involved with a focus on mitochondrial autophagy. Luteolin application (10 μM) in adult mouse cardiomyocytes overtly improved doxorubicin-induced cardiomyocyte contractile dysfunction including elevated peak shortening amplitude and maximal velocity of shortening/relengthening along with unchanged duration of shortening and relengthening. Luteolin alleviated doxorubicin-induced cardiotoxicity including apoptosis, accumulation of reactive oxygen species (ROS) and loss of mitochondrial membrane potential. Furthermore, luteolin attenuated doxorubicin-induced cardiotoxicity through promoting mitochondrial autophagy in association with facilitating phosphorylation of Drp1 at Ser⁶¹⁶, and upregulating TFEB expression. In addition, luteolin treatment partially attenuated low dose doxorubicin-induced elongation of mitochondria. Treatment of Mdivi-1, a Drp1 GTPase inhibitor, negated the protective effect of luteolin on levels of TFEB, LAMP1, and LC3B, as well as loss of mitochondrial membrane potential and cardiomyocyte contractile dysfunction in the face of doxorubicin challenge. Taken together, these findings provide novel insights for the therapeutic efficacy of luteolin against doxorubicin-induced cardiotoxicity possibly through improved mitochondrial autophagy.

Overexpression of COX5A protects H9c2 cells against doxorubicin-induced cardiotoxicity

Mitochondrial dysfunction plays a pivotal role in doxorubicin (DOX)-induced cardiomyopathy. Cytochrome c oxidase subunit 5A (COX5A) is a nuclear-encoded subunit of the terminal oxidase involved in mitochondrial electron transport. Although COX5A appears to play a key role in modulating the physiological activity of COX and involve in energy metabolism, the involvement of COX5A in DOX-induced cardiotoxicity remains unclear. In this study, we showed that COX5A was significantly downregulated by DOX treatment of H9c2 cells. Overexpression of COX5A in H9c2 cells effectively attenuated DOX-induced apoptosis. Meanwhile, DOX-induced decrease in mitochondrial membrane potential could be reserved by COX5A overexpression. Furthermore, COX5A overexpression relieved the DOX-induced suppression of mitochondrial respiration, due an increase in basal respiration, maximal respiration, ATP production, and spare respiratory capacity. These findings indicate that up-regulation of COX5A may inhibit the apoptosis and alleviate the mitochondrial dysfunction of DOX-treated H9c2 cells. Thus, COX5A may have potential for clinical use as a therapeutic target in DOX-induced cardiotoxicity.

Isodunnianol alleviates doxorubicin-induced myocardial injury by activating protective autophagy

Recurrent cardiotoxicity limits the clinical application of doxorubicin (DOX); however the detailed molecular mechanism of DOX cardiotoxicity remains unclear. In the current study, we found that a natural product extracted from Illicium verum, isodunnianol (IDN), mitigates DOX-induced cardiotoxicity by regulating autophagy and apoptosis both in vitro and in vivo. DOX suppressed protective autophagy and induced apoptosis in H9C2 cardiac myoblasts. Additionally, IDN demonstrated up-regulated autophagy and reduced apoptosis through the activation of the AMPK-ULK1 pathway. In addition, the beneficial effects of IDN on DOX which induced myocardial injury were dependent on AMPK and ULK1 phosphorylation. Similar results were also observed in a DOX-induced cardiotoxicity rat model. The combination of IDN and DOX resulted in decreased apoptosis and inflammatory myocardial fibrosis compared to the DOX mono-treatment group. In summary, our findings provide novel insights into the prevention of DOX-related toxicity by isodunnianol, a food source natural product, warranting further investigation.

Cathepsin K: The Action in and Beyond Bone

Cathepsin K (CatK) is one of the most potent proteases in lysosomal cysteine proteases family, of which main function is to mediate bone resorption. Currently, CatK is among the most attractive targets for anti-osteoporosis drug development. Although many pharmaceutical companies are working on the development of selective inhibitors for CatK, there is no FDA approved drug till now. Odanacatib (ODN) developed by Merck & Co. is the only CatK inhibitor candidate which demonstrated high therapeutic efficacy in patients with postmenopausal osteoporosis in Phase III clinical trials. Unfortunately, the development of ODN was finally terminated due to the cardio-cerebrovascular adverse effects. Therefore, it arouses concerns on the undesirable CatK inhibition in non-bone sites. It is known that CatK has far-reaching actions throughout various organs besides bone. Many studies have also demonstrated the involvement of CatK in various diseases beyond the musculoskeletal system. This review not only summarized the functional roles of CatK in bone and beyond bone, but also discussed the potential relevance of the CatK action beyond bone to the adverse effects of inhibiting CatK in non-bone sites.

Cardamonin protects against doxorubicin-induced cardiotoxicity in mice by restraining oxidative stress and inflammation associated with Nrf2 signaling

The clinical application of doxorubicin (DOX) for cancer treatment is limited due to its cardiotoxicity. However, the basic pathophysiological molecular mechanisms underlying DOX-induced cardiomyopathy have not yet been completely clarified, and the disease-specific therapeutic strategies are lacking. The aim of the present study was to investigate the potential cardioprotective effect of cardamonin (CAR), a flavone found in Alpinia plant, on DOX-induced cardiotoxicity in a mouse model. At first, in DOX-treated mouse cardiomyocytes, CAR showed significantly cytoprotective effects through elevating nuclear factor erythroid-2 related factor 2 (Nrf2) signaling, and reducing the degradation of Nrf2. This process then improved the anti-oxidant system, as evidenced by the up-regulated expression levels of haem oxygenase-1 (HO1), NAD(P)H:quinone oxidoreductase 1 (NQO1), glutamate-cysteine ligase modifier subunit (GCLM), superoxide dismutase (SOD), glutathione (GSH) and catalase (CAT). In contrast, DOX-induced increases in malondialdehyde (MDA) and reactive oxygen species (ROS) were highly inhibited by CAR treatments. Additionally, DOX-induced apoptosis and inflammatory response in cardiomyocytes were diminished by CAR through reducing the Caspase-3 and nuclear factor-κB (NF-κB) signaling pathways, respectively. Then, in the DOX-induced animal model with cardiotoxicity, we confirmed that through improving Nrf2 signaling, CAR markedly suppressed oxidative stress, apoptosis and inflammatory response in hearts of mice, improving cardiac function eventually. Together, our findings demonstrated that CAR activated Nrf2-related cytoprotective system, and protected the heart from oxidative damage, apoptosis and inflammatory injury, suggesting that CAR might be a potential therapeutic strategy in the prevention of DOX-associated myocardiopathy.

Bnip3 mediates doxorubicin-induced cardiomyocyte pyroptosis via caspase-3/GSDME

AIMS

This study was aimed to investigate the role of GSDME-mediated pyroptosis in cardiac injury induced by Doxorubicin (DOX), and to evaluate the role of BH3-only protein Bcl-2/adenovirus E1B 19-kDa-interacting protein 3 (Bnip3) in regulation of DOX-induced pyroptosis.

MAIN METHODS

HL-1 cardiomyocytes and C57BL/6J mice were treated by DOX to establish DOX-induced cardiotoxicity in vitro and in vivo models, respectively. Cell transfection was applied to regulate the expression of caspase-3, GSDME and Bnip3. Western blot was used for measuring expression of protein level. LDH-cytotoxicity assay was used to detect the LDH release. The Flow cytometry analysis was used to detect the cell death. Echocardiography was used to determine the cardiac function. HE staining was used for observing pathological feature of heart tissues.

KEY FINDINGS

Our results showed that GSDME-mediated pyroptosis was involved in DOX-induced cardiotoxicity in vivo. We showed that HL-1 cardiomyocytes exposed to DOX exhibited morphological features of pyroptosis in vitro. We also showed that DOX induced activation of caspase-3 and eventually triggered GSDME-dependent pyroptosis, which was reduced by the silence or inhibitor of caspase-3. We further showed that knockdown of GSDME inhibited DOX-induced cardiomyocyte pyroptosis in vitro. Finally, DOX increased the expression of Bnip3, whereas silencing of Bnip3 blunted cardiomyocyte pyroptosis induced by DOX, which was regulated through caspase-3 activation and GSDME cleavage.

SIGNIFICANCE

Our findings revealed a novel pathway that cardiomyocyte pyroptosis is regulated through Bnip3-caspase-3-GSDME pathway following DOX treatment, suggesting that Bnip3-dependent pyroptosis may offer a novel therapeutic strategy to reduce cardiotoxicity induced by DOX.

PGC1α activation by pterostilbene ameliorates acute doxorubicin cardiotoxicity by reducing oxidative stress via enhancing AMPK and SIRT1 cascades

Doxorubicin (DOX) is a widely used and potent anticancer agent, but DOX dose-dependently induced cardiotoxicity greatly limits its use in clinic. Pterostilbene, a natural analog of resveratrol, is a known antioxidant and exerts myocardial protection. The present study explored the action and detailed mechanism of pterostilbene on DOX-treated cardiomyocytes. We investigated the effects of pterostilbene on established acute DOX-induced cardiotoxicity models in both H9c2 cells treated with 1 μM DOX and C57BL/6 mice with DOX (20 mg/kg cumulative dose) exposure. Pterostilbene markedly alleviated the DOX exposure-induced acute myocardial injury. Both in vitro and in vivo studies revealed that pterostilbene inhibited the acute DOX exposure-caused oxidative stress and mitochondrial morphological disorder via the PGC1α upregulation through activating AMPK and via PGC1α deacetylation through enhancing SIRT1. However, these effects were partially reversed by knockdown of AMPK or SIRT1 in vitro and treatment of Compound C (AMPK inhibitor) or EX527 (SIRT1 inhibitor) in vivo. Our results indicate that pterostilbene protects cardiomyocytes from acute DOX exposure-induced oxidative stress and mitochondrial damage via PGC1α upregulation and deacetylation through activating AMPK and SIRT1 cascades.

Salsolinol Attenuates Doxorubicin-Induced Chronic Heart Failure in Rats and Improves Mitochondrial Function in H9c2 Cardiomyocytes

Backgrounds: Salsolinol (SAL), a plant-based isoquinoline alkaloid, was initially isolated from Aconiti Lateralis Radix Praeparata (ALRP) and identified as the active cardiotonic component of ALRP. This study was aimed to explore the therapeutic effect and mechanism by which SAL attenuates doxorubicin (DOX)-induced chronic heart failure (CHF) in rats and improves mitochondrial function in H9c2 cardiomyocytes.

Methods: Rats were intraperitoneally injected with DOX to establish CHF model. Therapeutic effects of SAL on hemodynamic parameters, serum indices, and the histopathology of the heart were analyzed in vivo. Moreover, H9c2 cardiomyocytes were pretreated with SAL for 2 h before DOX treatment in all procedures in vitro. Cell viability, cardiomyocyte morphology, proliferation, and mitochondrial function were detected by a high-content screening (HCS) assay. In addition, a Seahorse Extracellular Flux (XFp) analyzer was used to evaluate the cell energy respiratory and energy metabolism function. To further investigate the potential mechanism of SAL, relative mRNA and protein expression of key enzymes in the tricarboxylic acid cycle in vivo and mitochondrial calcium uniporter (MCU) signaling pathway-related molecules in vitro were detected.

Results: The present data demonstrated the pharmacological effect of SAL on DOX-induced CHF, which was through ameliorating heart function, downregulating serum levels of myocardial injury markers, alleviating histological injury to the heart, increasing the relative mRNA expression levels of key enzymes downstream of the tricarboxylic acid cycle in vivo, and thus enhancing myocardial energy metabolism. In addition, SAL had effects on increasing cell viability, ameliorating DOX-induced mitochondrial dysfunction, and increasing mitochondrial oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) in H9c2 cardiomyocyte. Moreover, we found that SAL might have an effect on improving mitochondrial respiratory function and energy metabolism via inhibiting excessive activation of MCU pathway in H9c2 cells. However, the protective effect could be ameliorated by ruthenium red (an MCU inhibitor) and abrogated by spermine (an MCU activator) in vitro.

Conclusion: The therapeutic effects of SAL on CHF are possibly related to ameliorating cardiomyocyte function resulting in promotion of mitochondrial respiratory and energy metabolism. Furthermore, the potential mechanism might be related to downregulating MCU pathway. These findings may provide a potential therapy for CHF.