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Fibronectin type III domain containing 4 (FNDC4) is highly homologous with FNDC5, which possesses various cardiometabolic protective functions. Emerging evidence suggests a noteworthy involvement of FNDC4 in fat metabolism and inflammatory processes. This study aimed to characterize the role of FNDC4 in myocardial ischemia/reperfusion (MI/R) injury and decrypt its underlying mechanisms. MI/R models of mice were established to investigate the alteration of FNDC4 in plasma and myocardium. We observed that plasma FNDC4 in MI/R-injury mice and patients experiencing acute myocardial infarction were both significantly reduced as opposed to their respective controls. Likewise, FNDC4 expression of myocardium decreased markedly in MI/R mice compared to the sham-operated group. Mice of FNDC4 knockout and myocardial overexpression were further introduced to elucidate the role of FNDC4 in MI/R injury by detecting cardiomyocyte apoptosis, myocardial infarct size, and cardiac function. Ablation of FNDC4 exacerbated cardiac dysfunction, increased myocardial infarction area and cardiomyocyte apoptosis when matched with wild-type mice post-MI/R. In contrast, FNDC4 overexpression through intramyocardial injection of rAAV9-Fndc4 significantly ameliorated cardiac function, reduced myocardial infarction area and cardiomyocyte apoptosis compared to sham group. Additionally, hypoxia-reoxygenation (H/R) was used to induce cardiomyocyte apoptosis, and to further elucidate the direct effects of FNDC4 on cardiomyocytes in vitro , and the results demonstrated that neonatal rat ventricular cardiomyocytes overexpressing FNDC4 showed less H/R-induced apoptosis, as evidenced by cleaved caspase 3 expression, TUNEL staining and flow cytometry. By performing RNA-seq analysis followed by cause-effect analysis, ERK1/2-Nrf2 pathway-mediated antioxidative effects were responsible for the protective roles of FNDC4 on cardiomyocytes. In summary, FNDC4 exerts cardioprotection against MI/R injury predominantly through mitigating oxidative stress responses and reducing cardiomyocyte apoptosis. These insights solidify the proposition of FNDC4 as a potential therapeutic aim for tackling MI/R damage. [Display omitted] • Cardiac and plasma FNDC4 was downregulated in mice with myocardial ischemia/reperfusion injury (MI/R). • FNDC4 deficiency exacerbates cardiac dysfunction, whereas FNDC4 overexpression leads to marked improvements in MI/R mice. • ERK1/2-Nrf2 was identified to mediate the anti-oxidative stress and anti-apoptotic effects of FNDC4 in cardiomyocytes. [ABSTRACT FROM AUTHOR]

Sepsis triggers myocardial injury and dysfunction, leading to a high mortality rate in patients. Cardiomyocyte apoptosis plays a positive regulatory role in septic myocardial injury and dysfunction. However, the mechanism is unclear.

Abstract Background Glucose fluctuations may be involved in the pathophysiological process of cardiomyocyte apoptosis, but the exact mechanism remains elusive. This study focused on exploring the mechanisms related to glucose fluctuation-induced cardiomyocyte apoptosis. Methods Diabetic rats established via an injection of streptozotocin were randomized to five groups: the controlled diabetic (CD) group, the uncontrolled diabetic (UD) group, the glucose fluctuated diabetic (GFD) group, the GFD group rats with the injection of 0.9% sodium chloride (NaCl) (GFD + NaCl) and the GFD group rats with the injection of N-acetyl-L-cysteine (NAC) (GFD + NAC). Twelve weeks later, cardiac function and apoptosis related protein expressions were tested. Proteomic analysis was performed to further analyze the differential protein expression pattern of CD and GFD. Results The left ventricular ejection fraction levels and fractional shortening levels were decreased in the GFD group, compared with those in the CD and UD groups. Positive cells tested by DAB-TUNEL were increased in the GFD group, compared with those in the CD group. The expression of Bcl-2 was decreased, but the expressions of Bax, cleaved caspase-3 and cleaved caspase-9 were increased in response to glucose fluctuations. Compared with CD, there were 527 upregulated and 152 downregulated proteins in GFD group. Txnip was one of the differentially expressed proteins related to oxidative stress response. The Txnip expression was increased in the GFD group, while the Akt phosphorylation level was decreased. The interaction between Txnip and Akt was enhanced when blood glucose fluctuated. Moreover, the application of NAC partially reversed glucose fluctuations-induced cardiomyocyte apoptosis. Conclusions Glucose fluctuations lead to cardiomyocyte apoptosis by up-regulating Txnip expression and enhancing Txnip-Akt interaction.

The objective of the study was to assess the therapeutic efficacy of targeting remote zone cardiomyocytes with cardiosphere‐derived cell (CDC) extracellular vesicles (EVs) delivered via intramyocardial and intravenous routes following acute myocardial infarction (MI). Cardiomyocyte (CM) cell death plays a significant role in left ventricular (LV) remodeling and cardiac dysfunction following MI. While EVs secreted by CDCs have shown efficacy in promoting cardiac repair in preclinical models of MI, their translational potential is limited by their biodistribution and requirement for intramyocardial delivery. We hypothesized that engineering the surface of EVs to target cardiomyocytes would enhance their therapeutic efficacy following systemic delivery in a model of acute MI. CDC‐derived EVs were engineered to express a CM‐specific binding peptide (CMP) on their surface and characterized for size, morphology, and protein expression. Mice with acute MI underwent both intramyocardial and intravenous delivery of EVs, CMP‐EVs and placebo in a double‐blind study. LVEF was assessed by echo at 2‐ and 28‐days post‐MI and tissue samples processed for assessment of EV biodistribution and histological endpoints. CMP‐EVs demonstrated superior cardiac targeting and retention when compared with unmodified EVs 24 h post‐MI. Mice treated with IV delivered CMP‐EVs demonstrated a significant improvement in LVEF and a significant reduction in remote zone cardiomyocyte apoptosis when compared with IV delivered non‐targeted EVs at 28‐day post‐MI. Systemic administration of CMP‐EVs improved cardiac function and reduced remote zone cardiomyocyte apoptosis compared with IV‐administered unmodified EVs, demonstrating a strategy to optimize therapeutic EV delivery post‐MI. [ABSTRACT FROM AUTHOR]

Anshen Shumai Decoction (ASSMD) is traditionally employed to manage coronary artery disease arrhythmias. Its protective efficacy against myocardial infarction remains to be elucidated. This investigation employed a rat model of myocardial infarction, achieved through the ligation of the left anterior descending (LAD) coronary artery, followed by a 28-day administration of ASSMD. The study observed the decoction's mitigative impact on myocardial injury, with gene regulation effects discerned through transcriptomic analysis. Furthermore, ASSMD's influence on cardiomyocyte apoptosis and fibrotic protein secretion was assessed using an embryonic rat cardiomyocyte cell line (H9c2) under hypoxic conditions and rat cardiac fibroblasts subjected to normoxic culture conditions with TGF-β. A functional rescue assay involving overexpression of FOS and Early Growth Response Factor 1 (EGR1), combined with inhibition of the p38 Mitogen-activated Protein Kinase (MAPK) pathway, was conducted. Results indicated that ASSMD significantly curtailed cardiomyocyte apoptosis and myocardial fibrosis in infarcted rats, primarily by downregulating FOS and EGR1 gene expression and inhibiting the upstream p38 MAPK pathway. These actions of ASSMD culminated in reduced expression of pro-apoptotic, collagen, and fibrosis-associated proteins, conferring myocardial protection and anti-fibrotic effects on cardiac fibroblasts. [ABSTRACT FROM AUTHOR]

Background: Myocardial ischemia-reperfusion injury (I/R) has been improved with drugs and effective reperfusion, but it still cannot be prevented. Methods: To investigate whether renal denervation (RDN) reduces cardiomyocyte apoptosis by ameliorating endoplasmic reticulum stress, 60 male specific pathogen-free (SPF) Wistar rats were randomly divided into 6 groups (n = 6). We established the I/R rat model by ligating the left anterior descending artery. The I/R+ angiotensin receptor neprilysin inhibitors (ARNI) group received ARNIs for 2 weeks until euthanasia. Results: The I/R+RDN and I/R+ARNI groups have signifiantly ameliorated left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) and reversed expansion of the left ventricular end-systolic diameter (LVSD) and left ventricular end diastolic diameter (LVDD) compared to the I/R group. The levels of norepinephrine (NE), angiotensin II, and aldosterone (ALD) increased signifiantly in the I/R group, but decreased signifiantly after RDN and ARNI intervention. In the I/R+RDN and I/R+ARNI groups, the myocardial tissue edema was alleviated. The infarct size was smaller in the I/R+RDN and I/R+ARNI groups compared to the I/R group. Apoptosis of cardiomyocytes and fib oblasts in myocardial tissue increased signifiantly in the I/R group, which was greatly diminished by RDN and ARNI. The expression of Bax, caspase-3, CHOP, PERK, and ATF4 protein was signifiantly increased in the I/R group, which compared to other groups, and the level of CHOP, PERK, and ATF4 gene expression increased. After RDN intervention, these expression levels recovered to varying degrees. Conclusion: The effect of RDN may be associated with regulating the endoplasmic reticulum stress PERK/ATF4 signaling pathway. [ABSTRACT FROM AUTHOR]

Background and aimAngelica sinensis (Oliv.) Diels (Danggui, DG), exhibits potential in myocardial infarction (MI) treatment. However, research on its synergistic combinations for cardioprotective effects has been limited owing to inadequate approaches.Experimental procedureWe identified certain phenolic acids and phthalein compounds in DG. Network pharmacology analysis and experimental validation revealed the components that protected H9c2 cells and reduced lactate dehydrogenase levels. Subsequently, a combination of computational experimental strategies and a secondary phenotypic optimization platform was employed to identify effective component combinations with synergistic interactions. The Chou-Talalay and Zero Interaction Potency (ZIP) models were utilized to quantify the synergistic relationships. The optimal combination identified, Z-Ligustide and Chlorogenic acid (Z-LIG/CGA), was evaluated for its protective effects on cardiac function and cardiomyocytes apoptosis induced by inflammatory in a mouse model of induced by left anterior descending coronary artery ligation. Flow cytometry was further utilized to detect the polarization ratio of M1/M2 macrophages and the expression of inflammatory cytokines in serum was measured, assessing the inhibition of inflammatory responses and pro-inflammatory signaling factors by Z-LIG/CGA.Key resultsQuadratic surface analysis revealed that the Z-LIG/CGA combination displayed synergistic cardioprotective effects (combination index value 10). In vivo, Z-LIG/CGA significantly improved cardiac function and reduced the fibrotic area in mice post-MI, surpassing the results in groups treated with Z-LIG or CGA alone. Compared to the MI group, the Z-LIG/CGA group exhibited decreased ratios of the myocardial cell apoptosis-related proteins BAX/Bcl-2 and Cleaved Caspase-3/Caspase-3 in mice. Further research revealed that Z-LIG/CGA treatment significantly increased IL-1R2 levels, significantly decreased IL-17RA levels, and inhibited the activation of p-STAT1, thereby alleviating cell apoptosis after MI. Additionally, the Z-LIG/CGA combination significantly inhibited the ratio of M1/M2 macrophages and suppressed the expression levels of pro-inflammatory cytokines IL-1β, IL-6, IL-17, and TNF-α in the serum.Conclusion and implicationsWe successfully identified a synergistic drug combination, Z-LIG/CGA, which improves MI outcomes by inhibiting cardiomyocyte apoptosis and inflammatory damage through modulating macrophage polarization and regulating the IL-1R2/IL-17RA/STAT1 signaling pathway. This study provides a charming paradigm to explore effective drug combinations in traditional Chinese medicine and a promising treatment for MI.

Heart failure with preserved ejection fraction (HFpEF) is a clinical syndrome characterized by pulmonary and systemic congestion resulting from left ventricular diastolic dysfunction and increased filling pressure. Currently, however, there is no evidence on effective pharmacotherapy for HFpEF. In this study, we aimed to investigate the therapeutic effect of total xanthones extracted from Gentianella acuta (TXG) on HFpEF by establishing an high‐fat diet (HFD) + L‐NAME‐induced mouse model. Echocardiography was employed to assess the impact of TXG on the cardiac function in HFpEF mice. Haematoxylin and eosin staining, wheat germ agglutinin staining, and Masson's trichrome staining were utilized to observe the histopathological changes following TXG treatment. The results demonstrated that TXG alleviated HFpEF by reducing the expressions of genes associated with myocardial hypertrophy, fibrosis and apoptosis. Furthermore, TXG improved cardiomyocyte apoptosis by inhibiting the expression of apoptosis‐related proteins. Mechanistic investigations revealed that TXG could activate the inositol‐requiring enzyme 1α (IRE1α)/X‐box‐binding protein 1 (Xbp1s) signalling pathway, but the knockdown of IRE1α using the IRE1α inhibitor STF083010 or siRNA‐IRE1α impaired the ability of TXG to ameliorate cardiac remodelling in HFpEF models. In conclusion, TXG alleviates myocardial hypertrophy, fibrosis and apoptosis through the activation of the IRE1α/Xbp1s signalling pathway, suggesting its potential beneficial effects on HFpEF patients. [ABSTRACT FROM AUTHOR]

The disruption of mitochondria homeostasis can impair the contractile function of cardiomyocytes, leading to cardiac dysfunction and an increased risk of heart failure. This study introduces a pioneering therapeutic strategy employing mitochondria derived from human umbilical cord mesenchymal stem cells (hu‐MSC) (MSC‐Mito) for heart failure treatment. Initially, we isolated MSC‐Mito, confirming their functionality. Subsequently, we monitored the process of single mitochondria transplantation into recipient cells and observed a time‐dependent uptake of mitochondria in vivo. Evidence of human‐specific mitochondrial DNA (mtDNA) in murine cardiomyocytes was observed after MSC‐Mito transplantation. Employing a doxorubicin (DOX)‐induced heart failure model, we demonstrated that MSC‐Mito transplantation could safeguard cardiac function and avert cardiomyocyte apoptosis, indicating metabolic compatibility between hu‐MSC‐derived mitochondria and recipient mitochondria. Finally, through RNA sequencing and validation experiments, we discovered that MSC‐Mito transplantation potentially exerted cardioprotection by reinstating ATP production and curtailing AMPKα‐mTOR‐mediated excessive autophagy. [ABSTRACT FROM AUTHOR]

Mechanical LV unloading for acute myocardial infarction (MI) is a promising supportive therapy to reperfusion. However, no data is available on exit strategy. We evaluated hemodynamic and cellular effects of reloading after Impella-mediated LV unloading in Yorkshire pigs. First, we conducted an acute study in normal heart to observe effects of unloading and reloading independent of MI-induced ischemic effects. We then completed an MI study to investigate optimal exit strategy on one-week infarct size, no-reflow area, and LV function with different reloading speeds. Initial studies showed that acute reloading causes an immediate rise in end-diastolic wall stress followed by a significant increase in cardiomyocyte apoptosis. The MI study did not result in any statistically significant findings; however, numerically smaller average infarct size and no-reflow area in the gradual reloading group prompt further examination of reloading approach as an important clinically relevant consideration. [ABSTRACT FROM AUTHOR]

Hypoxia-induced cardiomyocyte apoptosis is one major pathological change of acute myocardial infarction (AMI), but the underlying mechanism remains unexplored. CDC-like kinase 3 (CLK3) plays crucial roles in cell proliferation, migration and invasion, and nucleotide metabolism, however, the role of CLK3 in AMI, especially hypoxia-induced apoptosis, is largely unknown. The expression of CLK3 was elevated in mouse myocardial infarction (MI) models and neonatal rat ventricular myocytes (NRVMs) under hypoxia. Furthermore, CLK3 knockdown significantly promoted apoptosis and inhibited NRVM survival, while CLK3 overexpression promoted NRVM survival and inhibited apoptosis under hypoxic conditions. Mechanistically, CLK3 regulated the phosphorylation status of AKT, a key player in the regulation of apoptosis. Furthermore, overexpression of AKT rescued hypoxia-induced apoptosis in NRVMs caused by CLK3 deficiency. Taken together, CLK3 deficiency promotes hypoxia-induced cardiomyocyte apoptosis through AKT signaling pathway. [ABSTRACT FROM AUTHOR]

Coronary atherosclerosis‐induced myocardial ischemia leads to cardiomyocyte apoptosis. The regulatory mechanisms for cardiomyocyte apoptosis have not been fully understood. Circular RNAs are non‐coding RNAs which play important roles in heart function maintenance and progression of heart diseases by regulating gene transcription and protein translation. Here, we reported a conserved cardiac circular RNA, which is generated from the second exon of LRP6 and named circLRP62‐2. CircLRP62‐2 can protect cardiomyocyte from hypoxia‐induced apoptosis. The expression of circLRP62‐2 in cardiomyocytes was down‐regulated under hypoxia, while forced expression of circLRP62‐2 inhibited cell apoptosis. Normally, circLRP62‐2 was mainly localized in the nucleus. Under hypoxia, circLRP62‐2 is associated with heterogeneous nuclear ribonucleoprotein M (hnRNPM) to be translocated into the cytoplasm. It recruited hnRNPM to fibroblast growth factor 9 (FGF9) mRNA to enhance the expression of FGF9 protein, promoting hypoxia‐adaption and viability of cardiomyocytes. In summary, this study uncovers a new inhibitor of apoptosis and reveals a novel anti‐apoptotic pathway composed of circLRP62‐2, hnRNPM, and FGF9, which may provide therapeutic targets for coronary heart disease and ischemic myocardial injury. [ABSTRACT FROM AUTHOR]

Obstructive sleep apnea (OSA) is characterized by intermittent hypoxia (IH) and is strongly associated with adverse cardiovascular outcomes. Myocardial injury and dysfunction have been commonly observed in clinical practice, particularly in patients with severe OSA. However, the underlying mechanisms remain obscure. In this review, we summarized the molecular mechanisms by which IH impact on myocardial injury and dysfunction. In brief, IH-induced cardiomyocyte death proceeds through the regulation of multiple biological processes, including differentially expressed transcription factors, alternative epigenetic programs, and altered post-translational modification. Besides cell death, various cardiomyocyte injuries, such as endoplasmic reticulum stress, occurs with IH. In addition to the direct effects on cardiomyocytes, IH has been found to deteriorate myocardial blood and energy supply by affecting the microvascular structure and disrupting glucose and lipid metabolism. For better diagnosis and treatment of OSA, further studies on the molecular mechanisms of IH-induced myocardial injury and dysfunction are essential. [ABSTRACT FROM AUTHOR]

Qixue Shuangbu prescription (QSP) has been used for the treatment of chronic heart failure (CHF) with remarkable curative effect. Processed QSP (PQSP) could significantly improve the treatment of CHF after traditional Chinese medicine (TCM) processing. This study elucidated the underlying efficacy enhancement mechanism of QSP after TCM processing for treating CHF in vitro and in vivo. The injury of rat cardiomyoblast H9c2 cells was induced by anoxia/reoxygenation to mimic CHF state in vitro. Sixty Sprague-Dawley rats were used to established CHF model by intraperitoneally injecting doxorubicin (the accumulative dose 15 mg/kg). Biochemical examinations were performed in serum and cellular supernatant, respectively. Cardiac functions and histopathological changes were evaluated in CHF model rats. The protein and mRNA levels of ERK1/2, Bcl-2, Bax and Caspase-3 were evaluated by Western blot and RT-PCR, respectively. All above results of low dose crude QSP-treated group (L-CQSP), high dose CQSP-treated group (H-CQSP), low dose PQSP-treated group (L-PQSP), high dose PQSP-treated group (H-PQSP) were compared to systematically explore correlations between TCM processing and the efficacy enhancement for treating CHF of PQSP. Compared with the model group, the L-CQSP group showed significant improvement in cardiac function at 8th weeks, while no significant improvement in cardiomyocyte apoptosis and fibrosis. Both H-CQSP, L-PQSP and H-PQSP exerted beneficial therapeutic effects in injured H9c2 cardiomyocytes and CHF model rats. L-PQSP and H-PQSP significantly increased cell viability and the activity of SOD, decreased the activities of LDH, MDA and NO, up-regulated the expression of ERK1/2 and Bcl-2, down-regulated the expression of Bax and Caspase-3 compared to the same dosage of CQSP. The efficacy enhancement mechanism of PQSP after TCM processing for treating CHF was directly related to the regulation of ERK/Bcl-2/Bax/Caspases-3 signaling pathway.

Clinical application of doxorubicin (DOX) is heavily hindered by DOX cardiotoxicity. Several theories were postulated for DOX cardiotoxicity including DNA damage and DNA damage response (DDR), although the mechanism(s) involved remains to be elucidated. This study evaluated the potential role of TBC domain family member 15 (TBC1D15) in DOX cardiotoxicity. Tamoxifen-induced cardiac-specific Tbc1d15 knockout (Tbc1d15CKO) or Tbc1d15 knockin (Tbc1d15CKI) male mice were challenged with a single dose of DOX prior to cardiac assessment 1 week or 4 weeks following DOX challenge. Adenoviruses encoding TBC1D15 or containing shRNA targeting Tbc1d15 were used for Tbc1d15 overexpression or knockdown in isolated primary mouse cardiomyocytes. Our results revealed that DOX evoked upregulation of TBC1D15 with compromised myocardial function and overt mortality, the effects of which were ameliorated and accentuated by Tbc1d15 deletion and Tbc1d15 overexpression, respectively. DOX overtly evoked apoptotic cell death, the effect of which was alleviated and exacerbated by Tbc1d15 knockout and overexpression, respectively. Meanwhile, DOX provoked mitochondrial membrane potential collapse, oxidative stress and DNA damage, the effects of which were mitigated and exacerbated by Tbc1d15 knockdown and overexpression, respectively. Further scrutiny revealed that TBC1D15 fostered cytosolic accumulation of the cardinal DDR element DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Liquid chromatography–tandem mass spectrometry and co-immunoprecipitation denoted an interaction between TBC1D15 and DNA-PKcs at the segment 594–624 of TBC1D15. Moreover, overexpression of TBC1D15 mutant (∆594–624, deletion of segment 594–624) failed to elicit accentuation of DOX-induced cytosolic retention of DNA-PKcs, DNA damage and cardiomyocyte apoptosis by TBC1D15 wild type. However, Tbc1d15 deletion ameliorated DOX-induced cardiomyocyte contractile anomalies, apoptosis, mitochondrial anomalies, DNA damage and cytosolic DNA-PKcs accumulation, which were canceled off by DNA-PKcs inhibition or ATM activation. Taken together, our findings denoted a pivotal role for TBC1D15 in DOX-induced DNA damage, mitochondrial injury, and apoptosis possibly through binding with DNA-PKcs and thus gate-keeping its cytosolic retention, a route to accentuation of cardiac contractile dysfunction in DOX-induced cardiotoxicity.

Abstract Aims Molecular hydrogen has been exhibited a protective function in heart diseases. Our previous study demonstrated that hydrogen‐rich saline (HRS) could scavenge free radicals selectively and alleviate the inflammatory response in the myocardial ischaemia/reperfusion (I/R) injury, but the underlying mechanism has not been fully clarified. Methods and results Adult (10 weeks) C57BL/6 male mice and neonatal rat cardiomyocytes were used to establish I/R and hypoxia/reoxygenation (H/R) injury models. I/R and H/R models were treated with HRS to classify the mechanisms of cardioproctective function. In this study, we found that miR‐124‐3p was significantly decreased in both I/R and H/R models, while it was partially ameliorated by HRS pretreatment. HRS treatment also alleviated ischaemia‐induced apoptotic cell death and increased cell viability during I/R process, whereas silencing expression of miR‐124‐3p abolished this protective effect. In addition, we identified calpain1 as a direct target of miR‐124‐3p, and up‐regulation of miR‐124‐3 produced both activity and expression of calpain1. It was also found that compared with the HRS group, overexpression of calpain1 increased caspase‐3 activities, promoted cleaved‐caspase3 and Bax protein expressions, and correspondingly decreased Bcl‐2, further reducing cell viability. These results illustrated that calpain1 overexpression attenuated protective effect of HRS on cardiomyocytes in H/R model. Conclusions The present study showed a protective effect of HRS on I/R injury, which may be associated with miR‐124‐3p–calpain1 signalling pathway.

Abstract Broiler ascites syndrome (AS) is one of the main diseases threatening the health of broilers. It is well documented that myocardial hypertrophy and failure is one of the key mechanisms of broiler ascites syndrome. Therefore, prevention of cardiac hypertrophy and failure would be one goal to reduce broiler ascites syndrome incidence. Myocardial hypertrophy and failure are closely related to endoplasmic reticulum stress (ERS) in cardiac myocytes, and the endoplasmic reticulum stress signaling system (ATF6-DR5) is one of the important pathways of myocardial apoptosis. Excessive hypertrophy will affect the heart muscle’s normal contraction and diastole function, and the heart will turn from compensated to decompensate thus causing myocardial injury. Myocardial apoptosis is a core component of the pathological changes of this myocardial injury. Nano-selenium is a kind of red elemental selenium nanoparticle. Due to its excellent physical, chemical and biological properties, it has attracted extensive academic attention in recent years. It has been proven to have excellent antioxidant, antibacterial, antitumor, antihypertrophic, and antiapoptotic abilities. Herein, nano-selenium (1 µmol/L) can inhibit hydrogen peroxide (H2O2)-induced oxidative stress in broiler primary cardiomyocytes, and at the same time reduce cardiomyocyte apoptosis. In vivo, nano-selenium can reduce broiler myocardial injury-related enzyme indicators (AST, CK and LDH), and alleviate myocardial injury. It can also activate the antioxidant enzyme system (SOD, GSH-Px and CAT) and reduce MDA, and make the recovery of T-AOC ability in the organization. Meanwhile, nano-selenium can down-regulate the genes and proteins expression of ATF-6, GRP-78, CHOP and caspase 12 in the ERS-related signaling pathway, and inhibit that of downstream-related caspase 3, Bax and caspase 9, and increase that of the downstream anti-apoptotic Bcl-2, thereby maintaining the homeostasis of the endoplasmic reticulum and alleviating cardiomyocyte apoptosis. It can be seen that nano-selenium can protect the damaged myocardium in the broiler ascites caused by high-salt drinking by regulating the ATF6-DR5 signaling pathway. This study was performed in chickens and cardiomyocyte cells and attempted to demonstrate that selenium nanoparticles can protect the damaged myocardium in broiler ascites. This paper provides a new idea for preventing and treating broiler ascites syndrome.

Clinical application of doxorubicin (DOX) is heavily hindered by DOX cardiotoxicity. Several theories were postulated for DOX cardiotoxicity including DNA damage and DNA damage response (DDR), although the mechanism(s) involved remains to be elucidated. This study evaluated the potential role of TBC domain family member 15 (TBC1D15) in DOX cardiotoxicity. Tamoxifen-induced cardiac-specific Tbc1d15 knockout (Tbc1d15 CKO) or Tbc1d15 knockin (Tbc1d15 CKI) male mice were challenged with a single dose of DOX prior to cardiac assessment 1 week or 4 weeks following DOX challenge. Adenoviruses encoding TBC1D15 or containing shRNA targeting Tbc1d15 were used for Tbc1d15 overexpression or knockdown in isolated primary mouse cardiomyocytes. Our results revealed that DOX evoked upregulation of TBC1D15 with compromised myocardial function and overt mortality, the effects of which were ameliorated and accentuated by Tbc1d15 deletion and Tbc1d15 overexpression, respectively. DOX overtly evoked apoptotic cell death, the effect of which was alleviated and exacerbated by Tbc1d15 knockout and overexpression, respectively. Meanwhile, DOX provoked mitochondrial membrane potential collapse, oxidative stress and DNA damage, the effects of which were mitigated and exacerbated by Tbc1d15 knockdown and overexpression, respectively. Further scrutiny revealed that TBC1D15 fostered cytosolic accumulation of the cardinal DDR element DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Liquid chromatography–tandem mass spectrometry and co-immunoprecipitation denoted an interaction between TBC1D15 and DNA-PKcs at the segment 594–624 of TBC1D15. Moreover, overexpression of TBC1D15 mutant (∆594–624, deletion of segment 594–624) failed to elicit accentuation of DOX-induced cytosolic retention of DNA-PKcs, DNA damage and cardiomyocyte apoptosis by TBC1D15 wild type. However, Tbc1d15 deletion ameliorated DOX-induced cardiomyocyte contractile anomalies, apoptosis, mitochondrial anomalies, DNA damage and cytosolic DNA-PKcs accumulation, which were canceled off by DNA-PKcs inhibition or ATM activation. Taken together, our findings denoted a pivotal role for TBC1D15 in DOX-induced DNA damage, mitochondrial injury, and apoptosis possibly through binding with DNA-PKcs and thus gate-keeping its cytosolic retention, a route to accentuation of cardiac contractile dysfunction in DOX-induced cardiotoxicity. TBC1D15 directly binds and interacts with DNA-PKcs, leading to cytosolic DNA-PKcs accumulation with compromised DNA-PKcs nuclear translocation, exacerbated DNA damage, resulting in mitochondrial anomalies and doxorubicin-induced cardiomyocyte apoptosis. [Display omitted] [ABSTRACT FROM AUTHOR]

Doxorubicin (DOX) has aroused contradiction between its potent anti‐tumor capacity and severe cardiotoxicity. Galangin (Gal) possesses antioxidant, anti‐inflammatory, and antiapoptotic activities. We aimed to explore the role and underlying mechanisms of Gal on DOX‐induced cardiotoxicity. Mice were intraperitoneally injected with DOX (3 mg/kg, every 2 days for 2 weeks) to generate cardiotoxicity model and Gal (15 mg/kg, 2 weeks) was co‐administered via gavage daily. Nuclear factor erythroid 2‐related factor 2 (Nrf2) specific inhibitor, ML385, was employed to explore the underlying mechanisms. Compared to DOX‐insulted mice, Gal effectively improved cardiac dysfunction and ameliorated myocardial damage. DOX‐induced increase of reactive oxygen species, malondialdehyde, and NADPH oxidase activity and downregulation of superoxide dismutase (SOD) activity were blunted by Gal. Gal also markedly blocked increase of IL‐1β, IL‐6, and TNF‐α in DOX‐insulted heart. Mechanistically, Gal reversed DOX‐induced downregulation of Nrf2, HO‐1, and promoted nuclear translocation of Nrf2. ML385 markedly blunted the cardioprotective effects of Gal, as well as inhibitive effects on oxidative stress and inflammation. Gal ameliorates DOX‐induced cardiotoxicity by suppressing oxidative stress and inflammation via activating Nrf2/HO‐1 signaling pathway. Gal may serve as a promising cardioprotective agent for DOX‐induced cardiotoxicity. [ABSTRACT FROM AUTHOR]

Aims: Molecular hydrogen has been exhibited a protective function in heart diseases. Our previous study demonstrated that hydrogen‐rich saline (HRS) could scavenge free radicals selectively and alleviate the inflammatory response in the myocardial ischaemia/reperfusion (I/R) injury, but the underlying mechanism has not been fully clarified. Methods and results: Adult (10 weeks) C57BL/6 male mice and neonatal rat cardiomyocytes were used to establish I/R and hypoxia/reoxygenation (H/R) injury models. I/R and H/R models were treated with HRS to classify the mechanisms of cardioproctective function. In this study, we found that miR‐124‐3p was significantly decreased in both I/R and H/R models, while it was partially ameliorated by HRS pretreatment. HRS treatment also alleviated ischaemia‐induced apoptotic cell death and increased cell viability during I/R process, whereas silencing expression of miR‐124‐3p abolished this protective effect. In addition, we identified calpain1 as a direct target of miR‐124‐3p, and up‐regulation of miR‐124‐3 produced both activity and expression of calpain1. It was also found that compared with the HRS group, overexpression of calpain1 increased caspase‐3 activities, promoted cleaved‐caspase3 and Bax protein expressions, and correspondingly decreased Bcl‐2, further reducing cell viability. These results illustrated that calpain1 overexpression attenuated protective effect of HRS on cardiomyocytes in H/R model. Conclusions: The present study showed a protective effect of HRS on I/R injury, which may be associated with miR‐124‐3p–calpain1 signalling pathway. [ABSTRACT FROM AUTHOR]

Epidemiological studies have shown an increased risk of cardiovascular diseases in children born to mothers who smoked during pregnancy. The cardiovascular risk in the offspring associated with in utero nicotine exposure is further exaggerated by maternal obesity. The consumption of electronic cigarettes (e-cigarettes) is alarmingly increasing among adolescents and young adults without the knowledge of their harmful health effects. There has also been a substantial increase in e-cigarette use by women of reproductive age. This study investigates the detrimental effects of gestational exposure of e-cigarette and a high-fat diet (HFD) on neonatal hearts. Time-mated pregnant mice were fed a HFD and exposed to saline or e-cigarette aerosol with 2.4% nicotine from embryonic day 4 (E4) to E20. We demonstrated that in utero exposure of e-cigarettes and HFD from E4 to E20 triggers cardiomyocyte (CM) apoptosis in the offspring at postnatal day1 (PND1), PND3, and PND14. Induction of CM apoptosis following gestational exposure of e-cigarettes and HFD was associated with inactivation of AMP-activated protein kinase (AMPK), increased cardiac oxidative stress coupled with perturbation of cardiac BAX/BCL-2 ratio and activation of caspase 3 at PND 14. Electron microscopy further revealed that left ventricles of pups at PND14 after e-cigarette exposure exhibited apoptotic nuclei, convoluted nuclear membranes, myofibrillar derangement, and enlarged mitochondria occasionally showing signs of crystolysis, indicative of cardiomyopathy and cardiac dysfunction. Our results show profound adverse effects of prenatal exposure of e-cigarette plus HFD in neonatal hearts that may lead to long-term adverse cardiac consequences in the adult.

Introduction: The prevalence of ischemic heart disease has reached pandemic levels worldwide. Early revascularization is currently the most effective therapy for ischemic heart diseases but paradoxically induces myocardial ischemia/ reperfusion (MI/R) injury. Cardiac inflammatory reaction and oxidative stress are primarily involved in the pathology of MI/R injury. Low-intensity pulsed ultrasound (LIPUS) has been demonstrated to reduce cell injury by protecting against inflammatory reaction and oxidative stress in many diseases, including cardiovascular diseases, but rarely on MI/R injury. Methods: This study was designed to clarify whether LIPUS alleviates MI/R injury by alleviating inflammatory reaction and oxidative stress. Simultaneously, we have also tried to confirm which intensity of the LIPUS might be more suitable to ameliorate the MI/R injury, as well as to clarify the signaling mechanisms. MI/R and simulated ischemia/reperfusion (SI/R) were respectively induced in Sprague Dawley rats and human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs). LIPUS treatment, biochemical measurements, cell death assay, estimation of cardiac oxidative stress and inflammatory reaction, and protein detections by western blotting were performed according to the protocol. Results: In our study, both in vivo and in vitro, LIPUS of 0.1 W/cm² (LIPUS0.1) and 0.5 W/cm² (LIPUS0.5) make no significant difference in the cardiomyocytes under normoxic condition. Under the hypoxic condition, MI/R injury, inflammatory reaction, and oxidative stress were partially ameliorated by LIPUS0.5 but were significantly aggravated by LIPUS of 2.5 W/cm² (LIPUS2.5) both in vivo and in vitro. The activation of the apoptosis signal-regulating kinase 1 (ASK1)/c-Jun N-terminal kinase (JNK) pathway in cardiomyocytes with MI/R injury was partly rectified LIPUS0.5 both in vivo and in vitro. Conclusion: Our study firstly demonstrated that LIPUS of different intensities differently affects MI/R injury by regulating cardiac inflammatory reaction and oxidative stress. Modulations on the ASK1/JNK pathway are the signaling mechanism by which LIPUS0.5 exerts cardioprotective effects. LIPUS0.5 is promising for clinical translation in protecting against MI/R injury. This will be great welfare for patients suffering from MI/R injury. [ABSTRACT FROM AUTHOR]

Objective To investigate the effects of formononetin（FMN） on cardiomyocyte apoptosis and HSP90/AKT in rats with dilated cardiomyopathy-mediated heart failure. Methods Echocardiography, ELISA, histological staining, and TUNEL staining were used to observe the protective effect of different doses of FMN on dilated cardiomyopathy-mediated heart failure in rats and the apoptosis of cardiomyocytes. The potential targets of formononetin on dilated cardiomyopathy-mediated heart failure were obtained from TCMSP, DisGeNet, GeneCards, and other databases, the key targets were obtained according to the protein-protein interaction（PPI） network, and the key targets were verified by molecular docking. Western blotting was used to further verify the regulatory role of key targets in the treatment of dilated cardiomyopathy-mediated heart failure with formononetin. Results Formononetin could reduce the levels of LVIDS, LVIDD, NT-pro BNP, cTn-T, CK, CK-MB, and LDH in rats with dilated cardiomyopathy-mediated heart failure, increase the levels of EF and FS, and reduce the apoptosis of cardiomyocytes. FMN had a strong binding effect on 10 key targets（AKT1, HSP90AA1, CASP3, MAPK1, MMP9, SRC, ALB, HRAS, IGF1, and EGFR） screened by network pharmacology, with HSP90AA1 and AKT1 having the strongest binding effect. Formononetin decreased the expression of HSP90, AKT and downstream CASP3 protein, but increased the expression of p-AKT in myocardial tissue. Conclusion Formononetin may inhibit the expression of HSP90, promote phosphorylation of AKT to p-AKT, and inhibit the expression of CASP3, thereby reducing the apoptosis of cardiomyocytes and improving myocardial tissue damage, so as to achieve the purpose of treating dilated cardiomyopathy-mediated heart failure. [ABSTRACT FROM AUTHOR]

To explore the underlying mechanism of lncRNA MALAT1 in the pathogenesis of diabetic cardiomyopathy (DCM). DCM models were confirmed in db/db mice. MiRNAs in myocardium were detected by miRNA sequencing. The interactions of miR‐185‐5p with MALAT1 and RhoA were validated by dual‐luciferase reporter assays. Primary neonatal cardiomyocytes were cultured with 5.5 or 30 mmol/L D‐glucose (HG) in the presence or absence of MALAT1‐shRNA and fasudil, a ROCK inhibitor. MALAT1 and miR‐185‐5p expression were determined by real‐time quantitative PCR. The apoptotic cardiomyocytes were evaluated using flow cytometry and TUNEL staining. SOD activity and MDA contents were measured. The ROCK activity, phosphorylation of Drp1S616, mitofusin 2 and apoptosis‐related proteins were analysed by Western blotting. Mitochondrial membrane potential was examined by JC‐1. MALAT1 was significantly up‐regulated while miR‐185‐5p was down‐regulated in myocardium of db/db mice and HG‐induced cardiomyocytes. MALAT1 regulated RhoA/ROCK pathway via sponging miR‐185‐5p in cardiomyocytes in HG. Knockdown of MALAT1 and fasudil all inhibited HG‐induced oxidative stress, and alleviated imbalance of mitochondrial dynamics and mitochondrial dysfunction, accompanied by reduced cardiomyocyte apoptosis. MALAT1 activated the RhoA/ROCK pathway via sponging miR‐185‐5p and mediated HG‐induced oxidative stress, mitochondrial damage and apoptosis of cardiomyocytes in mice. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases (CVDs) are common causes of death, which take about 18.6 million lives worldwide every year. Currently, exploring strategies that delay ventricular remodeling, reduce cardiomyocyte death, and promote cardiomyocyte regeneration has been the hotspot and difficulty of the ischemic heart disease (IHD) research field. Previous studies indicate that piwi-interacting RNA (piRNA) plays a vital role in the occurrence and development of cardiac remodeling and may offer novel therapeutic strategies for cardiac repair. The best-known biological function of piRNA is to silence transposons in cells. In the cardiovascular system, piRNA is known to participate in cardiac progenitor cell proliferation, AKT pathway regulation, and cardiac remodeling and decompensation. In this review, we systematically discuss the research progress on piRNA in CVDs, especially the mechanism of cardiac remodeling and the potential functions in cardiac protection, which provides new insights for the progress and treatment of cardiovascular diseases. Piwi-interacting RNA (piRNA) is one of the noncoding RNAs, with the best -known biological function to silence transposons in cells. Now piRNA is found to participate in cardiac progenitor cell proliferation, AKT pathway regulation, cardiac remodeling and decompensation, which implies the potential of piRNA in the diagnosis and treatment of cardiovascular diseases. Over expression of piRNA could promote cardiac apoptosis and cardiac hypertrophy, thus targeted therapy which inhibits expression of associated piRNA may reduce cardiac remodeling and reduce inflammation caused by necrotic cardiomyocytes. PiRNA is also speculated to participate in the proliferation of cardiac progenitor cells, implying the potential to induce cardiac regeneration th erapy, which provides new insights for treatment of cardiovascular diseases. At present, the treatment strategy of cardiac remodeling emphasizes the control of risk factors, prevention of disease progression and individualized treatment. With further studies in mechanism of piRNA, potential therapies above may come true and more therapies in cardiovascular diseases may be found. [ABSTRACT FROM AUTHOR]

Broiler ascites syndrome (AS) is one of the main diseases threatening the health of broilers. It is well documented that myocardial hypertrophy and failure is one of the key mechanisms of broiler ascites syndrome. Therefore, prevention of cardiac hypertrophy and failure would be one goal to reduce broiler ascites syndrome incidence. Myocardial hypertrophy and failure are closely related to endoplasmic reticulum stress (ERS) in cardiac myocytes, and the endoplasmic reticulum stress signaling system (ATF6-DR5) is one of the important pathways of myocardial apoptosis. Excessive hypertrophy will affect the heart muscle's normal contraction and diastole function, and the heart will turn from compensated to decompensate thus causing myocardial injury. Myocardial apoptosis is a core component of the pathological changes of this myocardial injury. Nano-selenium is a kind of red elemental selenium nanoparticle. Due to its excellent physical, chemical and biological properties, it has attracted extensive academic attention in recent years. It has been proven to have excellent antioxidant, antibacterial, antitumor, antihypertrophic, and antiapoptotic abilities. Herein, nano-selenium (1 µmol/L) can inhibit hydrogen peroxide (H2O2)-induced oxidative stress in broiler primary cardiomyocytes, and at the same time reduce cardiomyocyte apoptosis. In vivo, nano-selenium can reduce broiler myocardial injury-related enzyme indicators (AST, CK and LDH), and alleviate myocardial injury. It can also activate the antioxidant enzyme system (SOD, GSH-Px and CAT) and reduce MDA, and make the recovery of T-AOC ability in the organization. Meanwhile, nano-selenium can down-regulate the genes and proteins expression of ATF-6, GRP-78, CHOP and caspase 12 in the ERS-related signaling pathway, and inhibit that of downstream-related caspase 3, Bax and caspase 9, and increase that of the downstream anti-apoptotic Bcl-2, thereby maintaining the homeostasis of the endoplasmic reticulum and alleviating cardiomyocyte apoptosis. It can be seen that nano-selenium can protect the damaged myocardium in the broiler ascites caused by high-salt drinking by regulating the ATF6-DR5 signaling pathway. This study was performed in chickens and cardiomyocyte cells and attempted to demonstrate that selenium nanoparticles can protect the damaged myocardium in broiler ascites. This paper provides a new idea for preventing and treating broiler ascites syndrome. [ABSTRACT FROM AUTHOR]

Activation of the local renin–angiotensin system (RAS) promotes cardiomyocyte apoptosis and cardiac remodeling after acute myocardial infarction (AMI). As an anti-RAS drug, the effect of Valsartan in the early stage of acute MI is limited by its low drug concentration in the heart and low dosage. Here, by exploiting the inherent nature of neutrophils migrating to the injured myocardium and the local low-pH microenvironment caused by ischemia and hypoxia after myocardial infarction, we designed nanocarrier (NSLP)-hybridized neutrophil membranes and pH-sensitive liposomes (SLPs) for the delivery of Valsartan (NSLP-Val). These functional nanocarriers could mimic neutrophils and are homed to the injured heart; they were also found to respond to a low-pH microenvironment. In the mouse model of MI, we found that NSLP-Val could target the infarct marginal zone and release Valsartan locally in the low-pH microenvironment without affecting hemodynamic stability. Further, locally released angiotensin receptor inhibitors reduced the infarct size and inflammatory response by inhibiting cardiomyocytes. Ultimately, NSLP-Val improved cardiac function and inhibited cardiac hypertrophy and fibrosis. [ABSTRACT FROM AUTHOR]

BACKGROUND: Cardiomyocyte apoptosis plays a critical role in ischemia/reperfusion injury. Recent studies have shown that PIWI-Interacting RNA (piRNA), a reproductive system regulator, participates in the pathogenesis of cardiac disorder. However, the role of piRNA in cardiomyocyte apoptosis has not been clarified; especially the mitochondria-dependent pathway involved is poorly understood. OBJECTIVE: To study the role and molecular mechanism of piRNA-5938 in cardiomyocyte apoptosis and mitochondrial fission. METHODS: The abundance of piRNA in normal and ischemic/reperfusion hearts of mice and rats was detected by deep sequencing, and the results were verified by real-time fluorescence quantitative PCR. Cardiac apoptosis was induced by hydrogen peroxide or anoxia/reoxygenation, in which the expression level of piRNA-5938 was detected by real-time fluorescence quantitative PCR. piRNA-5938 antagomir was synthesized and transfected into cardiomyocytes and then the cells were treated with hydrogen peroxide. Apoptosis was detected by TUNEL and mitochondrial division was evaluated by MitoTracker. RNAhybrid software was used to predict microRNAs that interact with piRNA-5938. RESULTS AND CONCLUSION: Compared with the sham group, the expression levels of 422 piRNAs were changed in the mouse ischemic/reperfusion heart, of which 289 were up-regulated and 133 were down-regulated, and piRNA-5938 expression increased significantly (P < 0.01). The expression level of piRNA-5938 was significantly up-regulated after cardiomyocyte apoptosis induced by H2O2 in a concentration-dependent manner (P < 0.05). piRNA-5938 was significantly increased after anoxia/reoxygenation-induced cardiomyocyte apoptosis (P < 0.01). Compared with the negative control group, knockdown of piRNA-5938 significantly reduced the apoptosis rate of cardiomyocytes induced by hydrogen peroxide (P < 0.05). The mitochondrial fission induced by hydrogen peroxide was significantly inhibited by the knockdown of piRNA-5938 (P < 0.05). piRNA-5938 was highly conserved in complementation with mitochondrial fission regulators mir-324 and Mir-668. To conclude, piRNA-5938 regulates cardiomyocyte apoptosis and mitochondrial fission, which probably functions through targeting mir-324 or mir-668. [ABSTRACT FROM AUTHOR]

BACKGROUND: In recent years, studies have found that the expression of thioredoxin-interacting protein is increased in the myocardial tissue of mice with myocardial infarction. Thioredoxin-interacting protein is the endogenous activator of the nucleotide-binding oligomerization domain-like receptor family pyrin domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome. It is unclear whether it participates in the pathological process of myocardial infarction by activating the inflammasome. OBJECTIVE: To investigate the effects of thioredoxin-interacting protein on cardiomyocyte apoptosis and NLRP3 inflammasomes, thereby providing new ideas for the prevention and treatment of myocardial infarction. METHODS: A total of 30 thioredoxin-interacting protein knockout mice and 30 wild-type littermate C57BL/6 mice were selected and randomly divided into myocardial infarction group and sham operation group with 15 mice in each group. Myocardial infarction models were established. Four days after the operation, some mice (10 mice in each group) were sacrificed and the heart tissue was collected. TdT-mediated dUTP nick end labeling was used to detect cardiomyocyte apoptosis in mice (5 mice in each group). Western blot (5 mice in each group) was used to detect the expression of thioredoxin-interacting protein, NLRP3, cleaved cysteinyl aspartate specific proteinase-1, apoptosis-associated speck-like protein containing CARD, cleaved interleukin-1β, and cleaved cysteinyl aspartate speacific proteinase-3. The remaining mice (5 mice in each group) were fed till 1 month after the operation. The cardiac function was detected by echocardiography before the mice were sacrificed and heart tissue samples were collected for later use. RESULTS AND CONCLUSION: The expression level of thioredoxin-interacting protein was significantly upregulated in the wild-type myocardial infarction group than the wild-type sham operation group (P < 0.05). Compared with the sham operation groups, the expressions of NLRP3, cleaved cysteinyl aspartate specific proteinase-1, apoptosis-associated speck-like protein containing CARD, cleaved interleukin-1β, and cleaved cysteinyl aspartate specific proteinase-3 proteins in the myocardium were significantly upregulated in the two myocardial infarction groups (P < 0.05). Compared with the wild-type myocardial infarction group, the expression levels of the above-mentioned five proteins were significantly downregulated, the cardiomyocyte apoptosis was reduced, and the cardiac function was significantly improved in the thioredoxin-interacting protein knockout mice with myocardial infarction (P < 0.05). To conclude, thioredoxininteracting protein knockout can inhibit the expression of NLRP3, cleaved cysteinyl aspartate specific proteinase-1, apoptosis-associated speck-like protein containing CARD, cleaved interleukin-1β, and cleaved cysteinyl aspartate specific proteinase-3 proteins, reduce cardiomyocyte apoptosis, and thereby improve cardiac function after myocardial infarction. It is expected to provide a target for the clinical treatment of myocardial infarction. [ABSTRACT FROM AUTHOR]

Nowadays the most effective way to cure myocardial infarction (MI) is reperfusion, which inevitably leads to cardiomyocyte apoptosis. In this study, we discussed the functions of SNHG15 in regulating cardiomyocyte apoptosis through the modulation of miR-188-5p/PTEN axis. We examined the links between SNHG15 and miR-188-5p/PTEN in mice with MI. Extensive experiments, measurements and comparisons were performed, including RT-PCR, western blotting, luciferase reporter assay, flow cytometry analysis etc. Through a series of comparisons and analysis, we discovered that SNHG15 could interact with the miR-188-5p/PTEN axis and impact the cellular physiology of cardiomyocyte apoptosis. PTEN was upregulated in hypoxia cells, but this effect was attenuated by miR-188-5p. MiR-188-5p could combine with SNHG15 and PTEN, and form a SNHG15-miR-188-5p-PTEN axis, which regulated the apoptosis of MCs. These results suggest that LncRNA SNHG15 regulates cardiomyocyte apoptosis induced by hypoxia or reperfusion injury through modulating of miR-188-5p/PTEN axis. [ABSTRACT FROM AUTHOR]

Background and objectives: Ischemic heart failure (HF) has become a disease that seriously endangers people's life and health. As a herbal formula widely used in clinical practice, new optimized Sheng-Mai-San (NO-SMS) has been shown to be significantly effective in improving cardiac function, increasing exercise tolerance, and slowing the progression of myocardial fibrosis in heart failure patients in multi-center clinical studies in various regions of China. In our previous pharmacodynamic and toxicological studies, we found that a medium-dose formulation (8.1 g of raw drug/kg) was the most effective in the treatment of heart failure, but its mechanism of action is still being investigated. The present study is exploring its relationship with cardiomyocyte apoptosis. Materials and methods: We investigated and verified this through two parts of experiments, in vivo and in vitro. Firstly, we prepared male SD rats with heart failure models by ligating the left anterior descending branch of the coronary artery (EF ≤ 50%), which were treated with NO-SMS Formula (8.1 g of raw drug/kg/d), Ifenprodil (5.4 mg/kg/d) or Enalapril (0.9 mg/kg/d) prepared suspensions by gavage for 4 weeks. The cardiac and structural changes were evaluated by echocardiography, H&E, and MASSON staining. The apoptosis of cardiomyocytes in each group was detected by Western blot, qRT-PCR, and ELISA. In vitro cell experiments include H9c2 cardiomyocyte injury induced by H2O2 and NMDA respectively, and the groups were incubated with NO-SMS and Ifenprodil-containing serum for 24 h. Apoptosis was detected by Annexin V-FITC/PI double-staining method, and the rest of the assays were consistent with the in vivo experiments. Results: Compared with the model group, the NO-SMS formula group and the Ifenprodil group could significantly improve cardiac function, delay myocardial fibrosis, reduce the expression of pro-apoptotic proteins, mRNA, and the concentration levels of Ca2+ and ROS in heart failure rats and H9c2 cardiomyocytes with H2O2 and NMDA-induced injury, which could significantly reduce the apoptosis rate of damaged cardiomyocytes and effectively inhibit the apoptosis of cardiomyocytes. Conclusion: NO-SMS Formula improved cardiac function, inhibited ventricular remodeling and cardiomyocyte apoptosis in HF rats, and its mechanism may be related to the regulation of the NMDAR signaling pathway, inhibition of large intracellular Ca2+ inward flow, and ROS production in cardiomyocytes.

Background Myocardial infarction (MI) is a cardiovascular disease with high morbidity and mortality. PI16 (peptidase inhibitor 16), as a secreted protein, is highly expressed in heart diseases such as heart failure. However, the functional role of PI16 in MI is unknown. This study aimed to investigate the role of PI16 after MI and its underlying mechanisms. Methods and Results PI16 levels after MI were measured by enzyme‐linked immunosorbent assay and immunofluorescence staining, which showed that PI16 was upregulated in the plasma of patients with acute MI and in the infarct zone of murine hearts. PI16 gain‐ and loss‐of‐function experiments were used to investigate the potential role of PI16 after MI. In vitro, PI16 overexpression inhibited oxygen–glucose deprivation–induced apoptosis in neonatal rat cardiomyocytes, whereas knockdown of PI16 exacerbated neonatal rat cardiomyocyte apoptosis. In vivo, left anterior descending coronary artery ligation was performed on PI16 transgenic mice, PI16 knockout mice, and their littermates. PI16 transgenic mice showed decreased cardiomyocyte apoptosis at 24 hours after MI and improved left ventricular remodeling at 28 days after MI. Conversely, PI16 knockout mice showed aggravated infract size and remodeling. Mechanistically, PI16 downregulated Wnt3a (wingless‐type MMTV integration site family, member 3a)/β‐catenin pathways, and the antiapoptotic role of PI16 was reversed by recombinant Wnt3a in oxygen–glucose deprivation–induced neonatal rat cardiomyocytes. PI16 also inhibited HDAC1 (class I histone deacetylase) expression, and overexpression HDAC1 abolished the inhibition of apoptosis and Wnt signaling of PI16. Conclusions In summary, PI16 protects against cardiomyocyte apoptosis and left ventricular remodeling after MI through the HDAC1‐Wnt3a‐β‐catenin axis.

Cardiomyocyte apoptosis has been characterized as one of the major mechanisms underlying doxorubicin (DOX)-induced cardiomyopathy. MicroRNA-21-5p (miR-21-5p) was reported to mitigate ischemia-induced cardiomyocyte apoptosis and cardiac injury. However, to our knowledge, the functional role of miR-21-5p in DOX-induced cardiomyopathy is unclear. In this study, we explored the role of miR-21-5p in DOX-induced cardiac injury. The expression level of miR-21-5p was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Dual luciferase reporter assay was used to verify the potential target gene of miR-21-5p. The apoptosis rate of NRCMs was detected by TUNEL staining assay. Western blot analysis was used to detect the protein expression levels of Bax, Bcl-2, Caspase3, cleaved-Caspase3 and BTG2. For animal studies, mice were injected with AAV9-miR-21-5p or AAV9-Empty viruses, and treated with DOX at a dose of 5 mg/kg per week through intraperitoneally administration. After 4 weeks of DOX treatment, mice were subjected to echocardiography to measure the left ventricular ejection fraction (EF) and fractional shortening (FS). Results showed that miR-21-5p was upregulated in both DOX-treated primary cardiomyocytes and mouse heart tissues. Interestingly, enhanced miR-21-5p expression inhibited DOX-induced cardiomyocyte apoptosis and oxidative stress, while decreased miR-21-5p expression promoted cardiomyocyte apoptosis and oxidative stress. Furthermore, cardiac overexpression of miR-21-5p protected against DOX-induced cardiac injury. The mechanistic study indicated that BTG2 was a target gene of miR-21-5p. The anti-apoptotic effect of miR-21-5p could be inhibited by BTG2 overexpression. Conversely, inhibition of BTG2 rescued the pro-apoptotic effect of miR-21-5p inhibitor. Taken together, our study showed that miR-21-5p could prevent DOX-induced cardiomyopathy by downregulating BTG2.

Sepsis remains a worldwide public health problem. This study aims to explore the role and mechanism of transcriptional factors (TFs) in sepsis‐induced myocardial injury. Firstly, TF KLF13 was selected to explore its role in sepsis‐induced myocardial injury. The caecal ligation and puncture (CLP) ‐induced sepsis mouse model was established and the septic mice were examined using standard histopathological methods. KLF13 expression was detected in the septic mouse heart and was also seen in a lipoploysaccharide (LPS) ‐induced cellular inflammation model. To explore this further both pro‐apoptotic cleaved‐caspase3/caspase3 and Bax levels and anti‐apoptotic Bcl2 levels were examined, also in both models, In addition inflammatory cytokine (IL‐1β, TNF‐α, IL‐8 and MCP‐1) production and IκB‐α protein level and p65 phosphorylation were examined in both septic mice and LPS‐induced cells. Thus three parameters ‐ cardiomyocyte apoptosis, inflammatory response and NF‐κB pathway activation were evaluated under similar conditions. The septic mice showed significant oedema, disordered myofilament arrangement and degradation and necrosis to varying degrees in the myocardial cells. KLF13 was downregulated in both the septic mouse heart and the LPS‐induced cellular inflammation model. Furthermore, both models showed abnormally increased cardiomyocyte apoptosis (increased cleaved‐caspase3/caspase and Bax protein levels and decreased Bcl2 level), elevated inflammation (increased production of inflammatory cytokines) and the activated NF‐κB pathway (increased p65 phosphorylation and decreased IκB‐α protein level). KLF13 overexpression notably ameliorated sepsis‐induced myocardial injury in vivo and in vitro. KLF13 overexpression protected against sepsis‐induced myocardial injury and LPS‐induced cellular inflammation and apoptosis via inhibiting the inflammatory pathways (especially NF‐κB signalling) and cardiomyocyte apoptosis. [ABSTRACT FROM AUTHOR]

Zhong-guo Fan,1 Yang Xu,1 Xi Chen,1 Ming-yue Ji,1,2 Gen-shan Ma1 1Department of Cardiology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, People’s Republic of China; 2Department of Cardiology, Lianshui People’s Hospital, Huaian, People’s Republic of ChinaCorrespondence: Gen-shan Ma, Department of Cardiology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, 210009, People’s Republic of China, Tel +86-13002580569, Email magenshan_D@163.comObjective: Dapagliflozin (DAPA) has been reported to have significant cardiac protective effects on heart failure (HF). However, the dose and time, as well as the underlying mechanisms, for DAPA treatment in acute myocardial infarction (AMI) remain controversial. The aim of this study aimed to assess the efficacy and safety of DAPA treatment along with an increased concentration gradient for AMI and explore the potential mechanisms.Methods: Non-diabetic Sprague-Dawley rats were used for establishing AMI models and then were treated with three different concentrations of DAPA [0.5 mg/kg, 1 mg/kg and 1.5 mg/kg, described as AMI+DAPA Low, AMI+DAPA Medium (Med) and AMI+DAPA High, respectively] for six weeks from the onsetting of AMI. Echocardiography, histological staining and Western blot were performed to assess the relevant cardiac protective effects. Mitochondrial biogenesis and myocardial apoptosis were evaluated via the electron microscopy and TUNEL assay, respectively, as well as the Immunoblotting. In vitro, H9c2 cells were subjected to hypoxic treatment to assess the efficacy of DAPA on mitochondrial biogenesis and apoptosis.Results: The medium dose of DAPA treatment could significantly reduce the infarct size (P < 0.01) and the echocardiography results showed that the MI-induced damage in cardiac function got partly repaired, showing no significant difference in left ventricle ejection fraction (LVEF) versus the Sham group (Sham vs AMI+DAPA Med group: 70.47% vs 61.73%). The Western blotting results confirmed the relevant benefits and the underlying mechanisms might be through the activation of PGAM5/Drp1 signaling pathway to normalize the mitochondrial fission and reduce cardiomyocyte apoptosis. Moreover, a medium dose of DAPA treatment could avoid increased damage to the bladder endothelium following higher treatment doses.Conclusion: Appropriate dose of DAPA treatment could improve the cardiac remodeling and reduce the cardiomyocyte apoptosis after AMI, without increased damage to bladder endothelium, which might be more preferred for MI patients without diabetes.Keywords: Dapagliflozin, acute myocardial infarction, mitochondrial fission, cardiomyocyte apoptosis

Dongjiu Li,1,&ast; Jiayin You,2,&ast; Chengyu Mao,1,&ast; En Zhou,1,&ast; Zhihua Han,1 Junfeng Zhang,1 Tiantian Zhang,1 Changqian Wang1 1Department of Cardiology, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People’s Republic of China; 2Department of Emergency, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Tiantian Zhang; Changqian Wang, Email ZhangTT2022Dr@163.com; wangcqdr17@163.comObjective: Cardiomyocyte apoptosis critically contributes to ischemia reperfusion injury (IRI), which lacks effective therapeutic strategies. Circular RNAs (circRNAs) serve as novel diagnostic and therapeutic targets in various cardiovascular diseases. CircRNA Fbxl5 is one of the abundantly expressed circRNAs in the heart and its role in myocardial IRI remains elusive.Materials and Methods: Wild-type (WT) mice and neonatal mice ventricular myocytes (NMVMs) were used and subjected to myocardial IRI and anoxia reoxygenation (AR), respectively. Molecular and histological analyses and echocardiography were used to determine the extent of apoptosis, infarct size, and cardiac function.Results: We found that circRNA Fbxl5 was significantly upregulated in the myocardium, as well as in NMVMs subjected to AR. Knockdown of circRNA Fbxl5 ameliorated cardiomyocyte apoptosis, thereby decreasing infarct size and preserving cardiac function. Additionally, in vitro knockdown of circRNA Fbxl5 in NMVMs subjected to AR recapitulated the in vivo findings. Mechanistically, we identified that circRNA Fbxl5 directly sponged and suppressed the endogenous microRNA-146a (miR-146a), thereby weakening its inhibitory effect on MED1, which could further promote the apoptosis of cardiomyocytes.Conclusion: Our findings revealed a novel and critical role for circRNA Fbxl5 in regulating cardiomyocyte apoptosis, and added additional insight into circRNAs mediated during myocardial IRI. The underlying miR-146a-MED1 signaling serves as an important cascade in regulating the apoptosis of cardiomyocytes.Keywords: myocardial ischemia reperfusion injury, circular RNA, microRNA-146a, cardiomyocyte apoptosis

Hypertension-induced cardiac disease is a common complication and a significant contributor to mortality in hypertensive patients, largely due to cardiomyocyte apoptosis. Although Trifolin has been identified as a potential antihypertensive compound, its therapeutic role in hypertension-induced cardiac injury remains uncertain. This study aims to evaluate the protective effects of Trifolin and explore the underlying mechanisms of its action against hypertension-induced cardiac injury. In vivo , mice were infused with Angiotensin II (AngII, 500 ng/kg/min) or saline via osmotic pumps and treated with Trifolin (0.1, 1.0, or 10.0 mg/kg/day) or Valsartan (10 mg/kg/day) for four weeks. In vitro , H9C2 cells were stimulated with AngII (1 μM) and treated with Trifolin (25, 50, or 100 μM). Various assays, including echocardiography, hematoxylin and eosin staining, TUNEL assay, Annexin-V/propidium iodide staining, and JC-1 staining, were used to assess Trifolin's therapeutic effects on hypertension-related cardiac injury and cardiomyocyte apoptosis. Potential pharmacological mechanisms were analyzed through network pharmacology and confirmed via Western blotting. Trifolin treatment improved cardiac function by increasing left ventricular ejection fraction and fractional shortening while reducing tissue disorganization in AngII-treated mice. It also reduced cardiomyocyte apoptosis, reversing the upregulation of Bax and cleaved caspase-3 and the downregulation of Bcl-2. Network pharmacology identified 314 common targets of Trifolin linked to hypertensive heart disease, with involvement in apoptosis, MAPK, PI3K/AKT, and HIF-1 signaling pathways. Trifolin treatment increased p-PI3K/PI3K and p-AKT/AKT ratios while decreasing p-ERK/ERK, p-p38 MAPK/p38 MAPK, and p-JNK/JNK ratios in both mouse and cell models. Trifolin alleviates AngII-induced cardiac injury and cardiomyocyte apoptosis, potentially through the regulation of MAPK, PI3K/AKT, and HIF-1 signaling pathways. [Display omitted] [ABSTRACT FROM AUTHOR]

Myocardial ischemia-reperfusion (I/R) injury induces significant apoptosis and reactive oxygen species (ROS) accumulation in cardiomyocytes. Coiled-coil domain-containing 8 (CCDC8), recently identified as an interacting protein of p53, acts as a cofactor in p53-mediated apoptosis. However, its role in myocardial I/R injury remains unclear. We first assessed CCDC8 levels in patients with left ventricular failure (LVF) and in both in vivo and in vitro models of myocardial I/R injury. Next, we used adenovirus 9 (AAV9) to overexpress CCDC8 and small interfering RNA (siRNA) to investigate the role of CCDC8 in myocardial I/R injury. mRNA sequencing and KEGG pathway analysis were performed to identify CCDC8-regulated genes. In vitro experiments were conducted to examine the effects of CCDC8 silencing on TNF-α-induced apoptosis. CCDC8 expression was elevated in the left ventricle of LVF patients and in the cardiomyocytes of mice subjected to myocardial I/R injury. Overexpression of CCDC8 in cardiomyocytes via AAV9 exacerbated cardiac dysfunction caused by myocardial I/R injury, while silencing CCDC8 suppressed apoptosis and ROS production in H9c2 cells under hypoxia-reoxygenation (H/R) conditions. mRNA sequencing and KEGG analysis indicated that CCDC8 regulates genes related to cardiac contractility and the TNF signaling pathway. Additionally, CCDC8 silencing reversed TNF-α-induced cardiomyocyte apoptosis in vitro. This study identifies CCDC8 as a key mediator of cardiomyocyte apoptosis via the TNF signaling pathway in myocardial I/R injury. These findings suggest that targeting CCDC8 could be a potential therapeutic strategy for mitigating cardiac dysfunction in myocardial I/R injury. [Display omitted] [ABSTRACT FROM AUTHOR]

MicroRNAs (miRs) are reported to regulate myocardial infarction (MI). This study was performed to investigate the function and mechanism of miR-17-5p in myocardial remodelling after MI. Initially, a mouse model of MI was established and MI mice were infected with lentivirus antago-miR-17-5p vector. High expression of miR-17-5p was found in myocardial tissues after MI. After inhibiting miR-17-5p expression, myocardial fibrosis, scarring, and cardiomyocyte apoptosis were improved, LC3-II/LC3-I ratio and Beclin-1 expression were decreased but p62 expression was increased. The dual-luciferase assay suggested that miR-17-5p targeted STAT3 and negatively regulated its expression. Then, after inhibiting STAT3 expression using STAT3 inhibitor S31-201, the fibrosis, scarring, and cardiomyocyte apoptosis were deteriorated, along with the rise of LC3-II/LC3-I and Beclin-1 expression, the reduction of p62 expression and the reversion of MI attenuation. In conclusion, inhibition of miR-17-5p can inhibit myocardial autophagy through targeting STAT3 and then inhibit myocardial remodelling, thereby protecting the myocardium after MI.

Diabetic cardiomyopathy (DCM) is highly prevalent and increases the risk of heart failure and sudden death. Therefore, proper and effective treatments for DCM are in urgent demand. Danlou tablet (Dan) is reported to confer protective effects on several heart diseases. However, to our knowledge, whether Dan provides protection against DCM is unclear. In this study, we explored the effect of Dan on DCM with the in vitro DCM model using AC16 cardiomyocytes. We found that Dan treatment significantly reduced cardiomyocyte apoptosis and oxidative stress in high-glucose (HG)-treated cardiomyocytes, as evidenced by decreased Annexin V-FITC+ cardiomyocytes, intracellular reactive oxygen species (ROS) levels, Bax/Bcl2 ratio, and cleaved-Caspase3/Caspase3 ratio. Interestingly, Dan treatment caused a decreased level of microRNA-34a (miR-34a), which could enhance cardiomyocyte apoptosis. Furthermore, miR-34a mimic blocked Dan's effect in apoptosis prevention. Finally, we observed that the miR-34a mimic effectively decreased the level of sirtuin 1 (SIRT1), while the miR-34a inhibitor increased the level of SIRT1. And downregulation of SIRT1 effectively reversed the effect of miR-34a inhibitor on cardiomyocyte apoptosis. Taken together, our study showed that Dan prevented HG-induced cardiomyocyte apoptosis through downregulating miR-34a and upregulating SIRT1. Our study has provided experimental support for the potential use of Dan in treating DCM. Further detailed study of Dan and the underlying mechanisms may shed light on the prevention and treatment of DCM.

Although previous studies showed that long non-coding RNAs (lncRNAs) have critical roles in the pathogenesis of acute myocardial infarction (AMI), the underlying molecular mechanism that lncRNAs participate in MI remains unclear. Herein, we explored the expression of lncRNA HOX antisense non-coding RNA (HOTAIR) in the serum of MI patients and mouse model of AMI. Biological functions of HOTAIR in hypoxic H9c2 cells, the in vitro model of MI, were also assessed. RT-qPCR results showed that HOTAIR expression was downregulated in the serum of AMI patients and AMI mice. HOTAIR overexpression promoted H9c2 cell viability and inhibited cell apoptosis under hypoxic conditions. Mechanically, HOTAIR was regulated by miR-206 and FN1 was the direct target of miR-206. More importantly, miR-206 overexpression or FN1 knockdown reversed the effect of HOTAIR overexpression on H9c2 cell viability and apoptosis under hypoxic conditions. Therefore, targeting the HOTAIR/miR-206/FN1 axis may be a promising therapeutic method for MI. [ABSTRACT FROM AUTHOR]

Objective: To investigate the potential mechanisms of the protective effects of Buyang Huanwu decoction (BYHWD) on cardiomyocyte apoptosis after myocardial infarction (MI) and to provide the foundation for the clinical application of BYHWD in preventing and treating cardiomyocyte apoptosis-related disorders after MI. Methods: The MI rat model was established by ligation of the left anterior descending (LAD) coronary artery. After the 20-week treatment with BYHWD, the following parameters were assessed to investigate the protective effects of BYHWD on cardiomyocyte apoptosis after MI, both in vivo and in vitro: mortality rate; heart weight/body weight (HW/BW); transthoracic echocardiography measurements; histopathological analysis; immunohistochemistry (IHC) analysis; TUNEL apoptosis assay; caspase-3 activity assay; aldehyde dehydrogenase-2 (ALDH2) enzymatic activity assay; malondialdehyde (MDA) content analysis; western blot analysis; MTT assay; and Hoechst 33342/PI apoptosis assay. Results: The mortality of the MI rats was significantly reduced by BYHWD treatment. Furthermore, BYHWD treatment significantly improved the heart function and significantly reduced the HW/BW ratio. Histopathological analysis showed that BYHWD treatment significantly relieved MI-induced cardiac injury and significantly decreased collagen formation. The TUNEL apoptosis assay showed that treatment with BYHWD reduced the cardiomyocyte apoptosis of MI rats in a dose-dependent manner. Moreover, BYHWD treatment could significantly inhibit oxidative stress-induced neonatal cardiomyocyte apoptosis, which is consistent with the results of animal experiments in vivo. Interestingly, the ALDH2 activity and protein expression was significantly reduced in the MI model group, while the content of toxic aldehydes, including 4-HNE and MDA, was increased. Importantly, BYHWD enhanced the activity of ALDH2 and the expression of ALDH2 protein and attenuated the content of toxic aldehydes in a dose-dependent manner. Furthermore, we found that co-treatment with an ALDH2 inhibitor, disulfiram, partially inhibited the cardiomyocyte protective effects of BYHWD. Conclusions: Collectively, our results suggest that BYHWD exerted anti-apoptotic effects in cardiomyocytes after MI by enhancing the ALDH2 activity and protein expression and decreasing the toxic aldehyde content.

To explore the mechanisms underlying the specific inhibitor targeting SGLT-2 empagliflozin in alleviating myocardial ischaemia–reperfusion (I/R) injury. A mouse model of I/R injury and H2O2-induced H9C2 cell model were established. The expressions of Bcl-2, Bax, LC3, Beclin1, GRP78, CHOP, PERK, ATF4, ATF6, IREα and P62 were examined by western blot, immunofluorescence or immunohistochemistry staining, respectively. The cardiac function was measured by echocardiography, TCC staining, lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) activity. Cell apoptosis was analysed by TUNEL, Annexin V/propidium iodide (PI) staining and caspase 3 and 9 activities. CCK-8 assay was used for analysing cell viability. PBA, TUDC and 3-MA were utilised for blocking ER stress and autophagy, respectively. Empagliflozin suppressed myocardial I/R injury in vivo and H2O2-induced cardiomyocyte apoptosis in vitro. Blockade of ER stress and autophagy inhibited H2O2-induced cardiomyocyte apoptosis. ER stress activated autophagy through the PERK signalling in H2O2-treated H9C2 cells. Empagliflozin suppressed ER stress-induced autophagy by inhibiting the PERK/ATF4/Beclin1 signalling. H2O2 and I/R-induced cardiomyocyte apoptosis was restrained by empagliflozin through inhibition of ER stress-induced autophagy. Empagliflozin suppressed ER stress-induced autophagy via suppressing the PERK/ATF4/Beclin1 signalling, thus alleviating myocardial I/R injury and cardiomyocyte apoptosis. [ABSTRACT FROM AUTHOR]

Hypoxia and reoxygenation (H/R) play a prevalent role in heart-related diseases. Histone demethylases are involved in myocardial injury. In this study, the mechanism of the lysine-specific histone demethylase 1A (KDM1A/LSD1) on cardiomyocyte apoptosis after myocardial ischemia-reperfusion injury (MIRI) was investigated. Firstly, HL-1 cells were treated with H/R to establish the MIRI models. The expressions of KDM1A and Sex Determining Region Y-Box Transcription Factor 9 (SOX9) in H/R-treated HL-1 cells were examined. The cell viability, markers of myocardial injury (LDH, AST, and CK-MB) and apoptosis (Bax and Bcl-2), and Caspase-3 and Caspase-9 protein activities were detected, respectively. We found that H/R treatment promoted cardiomyocyte apoptosis and downregulated KDM1A, and overexpressing KDM1A reduced apoptosis in H/R-treated cardiomyocytes. Subsequently, tri-methylation of lysine 4 on histone H3 (H3K4me3) level on the SOX9 promoter region was detected. We found that KDM1A repressed SOX9 transcription by reducing H3K4me3. Then, HL-1 cells were treated with CPI-455 and plasmid pcDNA3.1-SOX9 and had joint experiments with pcDNA3.1-KDM1A. We disclosed that upregulating H3K4me3 or overexpressing SOX9 reversed the inhibitory effect of overexpressing KDM1A on apoptosis of H/R-treated cardiomyocytes. In conclusion, KDM1A inhibited SOX9 transcription by reducing the H3K4me3 on the SOX9 promoter region and thus inhibited H/R-induced apoptosis of cardiomyocytes. [ABSTRACT FROM AUTHOR]

Jiang Zhu,1,&ast; Xia Zhang,2,&ast; Hong Xie,1 Yuye Wang,1 Xiaoxiao Zhang,1 Zhaoheng Lin3 1Department of Anesthesiology, The Second Affiliated Hospital of Soochow University, Suzhou, 215008, Jiangsu, People’s Republic of China; 2Department of Anesthesiology, Wuzhong People’s Hospital, Suzhou, Jiangsu, 215128, People’s Republic of China; 3Intensive Care Unit, People’s Hospital of Xishuangbanna Dai Nationality Autonomous Prefecture, Jinghong City, 666100, Yunnan, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Zhaoheng LinIntensive Care Unit, People’s Hospital of Xishuangbanna Dai Nationality Autonomous Prefecture, Galan South Road, Jinghong City, 666100, Yunnan, People’s Republic of ChinaTel +86691-2123836Fax +8615198406999Email linzh_med@163.comIntroduction: Doxorubicin (Dox) is an effective anticancer agent; however, its cardiotoxicity remains a challenge. Dysfunction of intracellular calcium ion (Ca2+) is implicated in the process of Dox-induced cardiomyocyte apoptosis. Although store-operated Ca2+ entry (SOCE) is suggested to be responsible for Ca2+ entry in cardiomyocytes, the direct role of store-operated Ca2+ channels in Dox-related cardiomyocyte apoptosis is unknown.Materials and Methods: Cardiomyocyte Stim1-specific knockout or overexpression mice were treated with Dox. Cardiomyocytes were pretreated with Stim1 adenovirus or siRNA followed by Dox incubation in vitro. Cardiac function and underlying mechanisms echocardiography were assessed via immunofluorescence, flow cytometry, real-time PCR, Western blotting and immunoprecipitation.Results: We observed the inhibition of Stim1 expression, association of Stim1 to Orai1 or Trpc1, and SOCE in Dox-treated mouse myocardium and cardiomyocytes. Orai1 and Trpc1 expression remained unchanged. Cardiomyocyte-specific deficiency of Stim1 exacerbated Dox-induced cardiac dysfunction and myocardial apoptosis. However, specific overexpression of Stim1 in the myocardium was associated with amelioration of cardiac dysfunction and myocardial apoptosis. In vitro, STIM1 knockdown potentiated Dox-induced AC16 human cardiomyocyte apoptosis. This apoptosis was attenuated by STIM1 upregulation. Moreover, STIM1 downregulation enhanced Dox-induced endoplasmic reticulum (ER) stress in cardiomyocytes. In contrast, STIM1 overexpression inhibited the activation of the above molecular markers of ER stress. Immunoprecipitation assay showed that STIM1 interacted with GRP78 in cardiomyocytes. This interaction was attenuated in response to Dox treatment.Conclusion: Our data demonstrate that cardiomyocyte STIM1 binding to GRP78 ameliorates Dox cardiotoxicity by inhibiting pro-apoptotic ER stress.Keywords: doxorubicin, cardiotoxicity, cardiomyocyte apoptosis, STIM1, endoplasmic reticulum stress

Cigarette smoking is an important risk factor for diabetes, cardiovascular disease and non-alcoholic fatty liver disease. The health risk associated with smoking can be aggravated by obesity. Smoking might also trigger cardiomyocyte (CM) apoptosis. Given that CM apoptosis has been implicated as a potential mechanism in the development of cardiomyopathy and heart failure, we characterize the key signaling pathways in nicotine plus high-fat diet (HFD)-induced CM apoptosis. Adult C57BL6 male mice were fed a normal diet (ND) or HFD and received twice-daily intraperitoneal (IP) injections of nicotine (0.75 mg/kg body weight [BW]) or saline for 16 weeks. An additional group of nicotine-treated mice on HFD received twice-daily IP injections of mecamylamine (1 mg/kg BW), a non-selective nicotinic acetylcholine receptor antagonist, for 16 weeks. Nicotine when combined with HFD led to a massive increase in CM apoptosis that was fully prevented by mecamylamine treatment. Induction of CM apoptosis was associated with increased oxidative stress and activation of caspase-2-mediated intrinsic pathway signaling coupled with inactivation of AMP-activated protein kinase (AMPK). Furthermore, nicotine treatment significantly (P