Cardiomyocyte Viability Research Articles

Berberine ameliorates septic cardiomyopathy through protecting mitochondria and upregulating Notch1 signaling in cardiomyocytes

IntroductionSeptic cardiomyopathy (SCM) arises as a consequence of sepsis-associated cardiovascular dysfunction, for which there is currently no specific targeted therapy available. Previous studies have demonstrated the beneficial therapeutic effect of berberine (BBR) on SCM; however, the underlying mechanisms of action remain unclear. The objective of this is to elucidate how BBR alleviates SCM.MethodsSeptic cardiomyopathy rat model was established by performing cecal ligation and puncture (CLP), while a cardiomyocyte injury model was provoked in H9C2 cells using lipopolysaccharide (LPS). Cardiac function was assessed through echocardiography, and myocardial histopathology was examined with hematoxylin-eosin (HE) staining. Cardiomyocyte viability was determined through Cell Counting Kit-8 (CCK8) assay, and measurement of ATP levels was done with an ATP assay kit. Mitochondrial ultrastructure was observed using transmission electron microscopy. Real-time polymerase chain reaction (RT-PCR) and Western blotting were employed to analyze the expression of Notch1 signaling pathway components and downstream molecules in myocardial tissues and cells.ResultIn vivo, BBR markedly improved symptoms and cardiac function in SCM rats, leading to enhanced ATP content, and ameliorated mitochondrial structure. Additionally, BBR increased Notch1 protein expression in myocardial tissue of the rats. In vitro, BBR elevated the survival rates of H9C2 cell, improved mitochondrial morphology, and raised ATP levels. The mRNA expression of Notch1, Hes1, and Hes2, and Notch1 protein expression was upregulated by BBR. While these effects were reversed upon inhibiting the Notch1 signaling pathway.ConclusionBBR improves septic cardiomyopathy by modulating Notch1 signaling to protect myocardial mitochondria.

Impaired Iron-Sulfur Cluster Synthesis Induces Mitochondrial PARthanatos in Diabetic Cardiomyopathy.

Diabetic cardiomyopathy (DCM), a severe complication of diabetes, is characterized by mitochondrial dysfunction, oxidative stress, and DNA damage. Despite its severity, the intrinsic factors governing cardiomyocyte damage in DCM remain unclear. It is hypothesized that impaired iron-sulfur (Fe-S) cluster synthesis plays a crucial role in the pathogenesis of DCM. Reduced S-sulfhydration of cysteine desulfurase (NFS1) is a novel mechanism that contributes to mitochondrial dysfunction and PARthanatos in DCM. Mechanistically, hydrogen sulfide (H2S) supplementation restores NFS1 S-sulfhydration at cysteine 383 residue, thereby enhancing Fe-S cluster synthesis, improving mitochondrial function, increasing cardiomyocyte viability, and alleviating cardiac damage. This study provides novel insights into the interplay between Fe-S clusters, mitochondrial dysfunction, and PARthanatos, highlighting a promising therapeutic target for DCM and paving the way for potential clinical interventions to improve patient outcomes.

Cellular viability in an in vitro model of human ventricular cardiomyocytes (RL-14) exposed to gold nanoparticles biosynthesized using silk fibroin from silk fibrous waste

In nanotechnology, tissue engineering proposes obtaining nanomaterials of natural or synthetic origin, looking to incorporate components that exhibit a defined shape, diameter, colloidal stability, and biological identity to promote and regulate the events that occur in a cardiac cell microenvironment. This research aimed to evaluate cellular viability in an in vitro model of human fetal ventricular cardiomyocytes on interaction with gold nanoparticles biosynthesized using silk fibroin from silk fibrous waste. The Physicochemical properties were characterized by UV-visible spectroscopy, Fourier-transform infrared spectroscopy, electrokinetic potential, and scanning transmission electron microscopy. Moreover, the MTT assay was used to determine the cell viability of cardiomyocytes exposed to gold nanoparticles. The results showed that the variation of the pH of the reaction allows the synthesis of different geometries of nanoparticles with diameters between 6 and 334 nm. Furthermore, it was found that the nanoparticles with a tendency to sphericity favor the cell viability of cardiomyocytes.

Metformin Attenuates Myocardial Ischemia-Reperfusion Injury through the AMPK-HMGCR-ROS Signaling Axis.

To explore the role and mechanism of metformin (MET) in regulating myocardial injury caused by cardiac ischemia-reperfusion. A rat model of myocardial ischemia-reperfusion injury was established by ligation of the anterior descending branch of the left coronary artery. The myocardial area at risk and the infarction size were measured by Evans blue and 2,3,5‑triphenyltetrazole chloride (TTC) staining, respectively. Terminal Deoxynucleotidyl Transferase-Mediated dUTP Nick End Labeling (TUNEL) staining was used to detect apoptosis of cardiomyocytes. The expression of 4‑hydroxynonenal (4‑HNE) was detected by immunohistochemical staining. Real-time quantitative polymerase chain reaction (RT-PCR) and Western blot were used to detect mRNA and expression of the Adenosine 5'-monophosphate-activated protein kinase (AMPK) - 3‑hydroxy-3‑methylglutaryl-CoA reductase (HMGCR) signaling pathway, respectively. MET treatment decreased the infarct size and the activity of the myocardial enzyme profile, thus demonstrating protection of ischemic myocardium. The number of TUNEL positive cells significantly decreased. Immunohistochemical results showed that MET decreased the expression of 4‑HNE in myocardial tissue and the content of malondialdehyde (MDA) in myocardial cells. Further experimental results showed that MET decreased HMGCR transcription and protein expression, and increased AMPK phosphorylation. In the model of hypoxia and reoxygenation injury of cardiomyocytes, MET increased the viability of cardiomyocytes, decreased the activity of lactic dehydrogenase (LDH), decreased malondialdehyde content and intracellular reactive oxygen species (ROS) concentrations, and regulate the AMPK-HMGCR signaling pathway through coenzyme C (ComC). MET inhibits the expression of HMGCR by activating AMPK, reduces oxidative damage and apoptosis of cardiomyocytes, and alleviates myocardial ischemia-reperfusion injury.

The contribution of SLC7A11-mediated ferroptosis to cardiac injury in iron overload cardiomyopathy: an in vitro study

Abstract Background Recent studies have indicated that iron overload can induce myocardial ferroptosis in iron overload cardiomyopathy (IOC), but the specific mechanisms, including the role of SLC7A11, remain unclear. Purpose By delving into the role of SLC7A11-mediated ferroptosis in IOC, this research endeavors to provide novel insights and therapeutic strategies for understanding and treating IOC. Methods To induce an in vitro model of IOC, wild-type rat cardiomyocytes (H9C2) were cultured in a ferric citrate (FAC) medium. Cardiomyocytes were exposed to various concentrations of iron overload (ranging from 0 mM to 2 mM) for durations of 4, 8, 12, and 24 hours. Cell viability at different FAC concentrations was assessed by the cell counting kit-8 (CCK8) assay and the level of the ferroptosis indicator malondialdehyde (MDA) was measured to determine the optimal concentration and duration of FAC treatment which was required to establish the IOC cell model. Next, ferroptosis indicators, including MDA, prostaglandin peroxide synthase 2 (PTGS2), and glutathione peroxidase 4 (GPX4), and the pivotal factor, SLC7A11 of IOC cardiomyocytes were evaluated. The protein and mRNA levels of SLC7A11 were assessed by molecular biology techniques. Additionally, the mitochondrial morphology of the IOC cardiomyocytes was meticulously examined by transmission electron microscopy (TEM). Flow cytometry was employed for detecting reactive oxygen species (ROS) levels. Furthermore, we elucidated the underlying mechanism of myocardial injury in IOC by overexpressing SLC7A11 and subsequently detecting changes in ferroptosis markers. Results CCK-8 results showed that the viability of cardiomyocytes exhibited dose-dependently with increasing FAC concentration (R2=0.5483, p<0.0001). Furthermore, the viability of cardiomyocytes remained relatively stable, with survival rates of approximately 50% and not decreasing below 50%. Additionally, the MDA content in IOC cardiomyocytes increased dose-dependently with the elevation of FAC concentration (R2=0.75, p<0.05), with a significant increase observed at 0.75mM. Expression levels of ferroptosis marker genes, GPX4 and PTGS2, both at the mRNA and protein levels, are indicative of diminished antioxidant capacity. Meanwhile, the level of myocardial MDA and ROS were markedly elevated, indicating underscoring increased oxidative stress within the IOC cardiomyocytes. Moreover, there was a downregulation in the expression of SLC7A11 mRNA and protein in IOC cardiomyocytes, suggesting a potential compensatory mechanism to counteract oxidative damage. TEM further elucidated cardiac mitochondrial injuries in IOC rats, including focal vacuolization, swelling, crest disruption, and even disappearance. Overexpression of SLC7A11 resulted in a significant augmentation of GPX4 and a reduction of PTGS2mRNA and protein expression levels. Conclusions Ferroptosis, mediated by SLC7A11, may represent a pivotal mechanism underlying myocardial injury in IOC.

A refined TTC assay precisely detects cardiac injury and cellular viability in the infarcted mouse heart

Histological analysis with 2,3,5-triphenyltetrazolium chloride (TTC) staining is the most frequently used tool to detect myocardial ischemia/reperfusion injury. However, its practicality is often challenged by poor image quality in gross histology, leading to an equivocal infarct-boundary delineation and potentially compromised measurement accuracy. Here, we introduce several crucial refinements in staining protocol and sample processing, which enable TTC images to be analyzed with light microscopy. The refined protocol involves a two-step TTC staining process (perfusion and immersion) and subsequent Zamboni fixation to differentiate myocardial viability and necrosis, and use of Coomassie brilliant blue to label area-at-risk. After the duo-staining steps were completed, the heart sample was embedded and sliced transversally by a cryostat into a series of thin sections (50 µm) for microscopic analysis. The refined TTC (redTTC) assay yielded remarkably high-quality images with striking color intensity and sharply defined boundaries, permitting unambiguous and reliable delineation of the infarct and area-at-risk. In the same animals, the redTTC assay showed good agreement with the in-vivo gold standard measurements (LGE and MEMRI). Meanwhile, redTTC imaging allows tracking of viable cardiomyocytes at cellular resolution, and with this enhanced capability, we convincingly demonstrated the pro-survival action of stem cells based-therapy. Therefore, the redTTC assay represents a significant technical advance that permits precise detection of the true extent of cardiac injury and cardiomyocyte viability. This approach is cost-effective and may be adapted for use in diverse applications, making it highly appealing to many laboratories performing ischemia/reperfusion injury experiments.

Next generation preservation solution using synthetic enzymes added to polyhemoglobin to protect warm ischemic human hepatocytes and cardiomyocytes

This study investigates the potential improvement of polyhemoglobin’s protective properties by the addition of 3 synthetic enzymes (neo-carbonic anhydrase, neo-catalase and neo-superoxide dismutase) to polyhemoglobin after 90 and 180 min of warm in-vitro ischemia (100% Nitrogen at 37 °C). Following the warm ischemic shock, cell cultures were subjected to various treatment solutions: Controls; PolyHb; 3 neoenzymes; PolyHb + 3 neoenzymes; PolyHb + 2 neoenzymes. The cultures were then incubated (Oxygen, 5% CO2 at 37 °C) for 24 h followed by several analyses. Compared to polyhemoglobin alone, this novel solution containing polyhemoglobin + 3 neoeznymes significantly increased the viability, cell growth, albumin production, protection against oxidative stress and cellular injury of human hepatocytes. Moreover, this also protects the viability of human cardiomyocytes. These findings suggest that it could be useful as a pre-transplant cell/organ preservation solution which, in the long-term, could contribute to the development of blood substitutes.

WITHDRAWN: Shenmai Injection Exerts the Cardioprotective Effects by Modulating Autophagy-apoptosis via Beclin-1

Background and aimDespite the excellent efficacy of anthracyclines, their clinical application is subject to cardiotoxicity. Studies have shown that Shenmai Injection(SMI) alleviated anthracycline-induced myocardial injury, however, the exact mechanism has not been clarified. Experimental procedureEach intervention was explored by detecting the viability of cardiomyocytes, LDH leakage rate, and CK levels. Finally, the effects of each intervention on autophagy-apoptosis and Beclin-1 were observed by using mCherry-EGFP-LC3B double fluorescence method, Annexin V/propidium iodide (PI), and protein immunoblotting method to explain the mechanism of Shenmai Injection. Key resultsThe viability of H9c2 cells in the model group decreased, accompanied by elevated LDH leakage rate and CK levels after doxorubicin intervention (P<0.01 or P<0.05). In contrast, SMI reversed above situation (P<0.01 or P<0.05). Besides, autophagy and apoptosis up-regulated in the model group (P<0.01), accompanied by upregulated Beclin-1, LC3-II, LC3-II/LC3-I, apoptosis effector proteins Cleaved-Caspase-9, Cleaved-Caspase-9/Caspase-9, Cleaved-Caspase-3, Cleaved-Caspase-3/Caspase-3 expressions and the downregulation of p62 protein, anti-apoptotic protein Bcl2 expressions (P<0.01 or P<0.05). Nonetheless, autophagy and apoptosis were decreased with the help of SMI (P<0.01 or P<0.05). ConclusionSMI alleviated autophagy and apoptosis of damaged cardiomyocytes by regulating Beclin-1.

Valtrate Suppresses TNFSF14-Mediated Arrhythmia After Myocardial Ischemia-Reperfusion by Inducing N-linked Glycosylation of LTβR to Regulate MGA/MAX/c-Myc/Cx43.

Myocardial ischemia-reperfusion (MIR)-induced arrhythmia remains a major cause of death in patients with cardiovascular diseases. The reduction of Cx43 has been known as a major inducer of arrhythmias after MIR, but the reason for the reduction of Cx43 remains largely unknown. The aim of this study was to find the key mechanism underlying the reduction of Cx43 after MIR and to screen out an herbal extract to attenuate arrhythmia after MIR. The differentially expressed genes in the peripheral blood mononuclear cell (PBMCs) after MIR were analyzed using the data from several gene expression omnibus data sets, followed by the identification in PBMCs and the serum of patients with myocardial infarction. Tumor necrosis factor superfamily protein 14 (TNFSF14) was increased in PBMCs and the serum of patients, which might be associated with the injury after MIR. The toxic effects of TNFSF14 on cardiomyocytes were investigated in vitro . Valtrate was screened out from several herbal extracts. Its protection against TNFSF14-induced injury was evaluated in cardiomyocytes and animal models with MIR. Recombinant TNFSF14 protein not only suppressed the viability of cardiomyocytes but also decreased Cx43 by stimulating the receptor LTβR. LTβR induces the competitive binding of MAX to MGA rather than the transcriptional factor c-Myc, thereby suppressing c-Myc-mediated transcription of Cx43. Valtrate promoted the N-linked glycosylation modification of LTβR, which reversed TNFSF14-induced reduction of Cx43 and attenuated arrhythmia after MIR. In all, valtrate suppresses TNFSF14-induced reduction of Cx43, thereby attenuating arrhythmia after MIR.

Carvacrol-conjugated 3-Hydroxybenzoic Acids: Design, Synthesis, cardioprotective potential against doxorubicin-induced Cardiotoxicity, and ADMET study

Carvacrol (CA) is a phenolic monoterpene renowned for its diverse pharmacological benefits, particularly its cardioprotective effects. Concurrently, phenolic acids have also demonstrated promise in mitigating drug-induced cardiotoxicity. Focusing on combating doxorubicin-induced cardiotoxicity (DIC), the research aims to synthesize novel cardioprotective agents by combining CA with 3-hydroxybenzoic acid (3HA). Doxorubicin, an anticancer drug, poses cardiovascular risks as its adverse effect, prompting the exploration of hybrid compounds. Various linker molecules, including alkyl and acyl with different carbon lengths, were investigated to understand their impact on bioactivity. In vitro testing on the DOX-induced H9c2 cell death model revealed the effectiveness of a CA conjugate in preserving cardiomyocyte viability. In silico analysis highlighted favorable drug-like properties and low toxicity of the conjugate. This study sheds light on molecular hybridization’s potential in developing cardioprotective agents, emphasizing CA’s pivotal role in combating DIC.

Inhibition of ubiquitin-specific protease 7 ameliorates ferroptosis-mediated myocardial infarction by contrasting oxidative stress: An in vitro and in vivo analysis

BackgroundOur prior research determined that USP7 exacerbates myocardial injury. Additionally, existing studies indicate a strong connection between USP7 and ferroptosis. However, the influence of USP7 on ferroptosis-mediated myocardial infarction (MI) remains unclear. Given these findings, we are particularly interested in USP7's regulatory role in ferroptosis-mediated MI and its underlying mechanisms. MethodsIn this study, we established MI models and lentivirus-transfected groups to inhibit USP7 expression both in vivo and in vitro. Cardiac function was detected with Echocardiography. TTC and HE staining were employed to assess myocardial alterations. The expression of ferroptosis markers (PTGS2, ACSL4, GPX4) were analyzed by RT-qPCR and Western blotting. Flow cytometry and ELISA were used for measuring Fe2+, lipid ROS, GSH, and GSSG levels. TEM and Prussian blue staining were used to observe mitochondrial alterations and iron deposition. RT-qPCR, Western blotting, and immunofluorescence were conducted to analyze Keap1, Nrf2, and nuclear Nrf2 expression in vitro and in vivo. ResultsIn the MI model group, USP7 expression significantly increased, worsening ferroptosis-mediated MI. Conversely, in the USP7-inhibited group, activation of the Keap1-Nrf2 signaling pathway improved ferroptosis-mediated MI outcomes. In vitro, the MI model exhibited a marked decline in cardiomyocyte viability and notable mitochondrial damage. However, these issues improved in the USP7-inhibited groups. In vivo, USP7 intensified MI and iron deposition within the MI model group, with decreased values of LVEF, LVFS, SV, LVAWd, and LVPWs, all of which showed improvement in the USP7-inhibited group, except for LVPWd and LVPWs, which showed no significant variation. Importantly, both the in vitro and in vivo experiments revealed analogous results: a reduction in Keap1 expression and an increase in both Nrf2 and nuclear Nrf2 post USP7 inhibition. Additionally, GPX4 expression decreased while PTGS2 and ACSL4 expressions increased. Notably, concentrations of Fe2+, lipid ROS, GSH, and GSSG significantly decreased. ConclusionIn vitro and in vivo studies have found that inhibition of USP7 attenuates iron deposition and suppresses oxidative stress, resulting in amelioration of ferroptosis-induced MI.

Multi-faceted potential of sophoridine compound's anti-arrhythmic and antioxidant effects through ROS/CaMKII pathway

Cardiac arrhythmias remain a significant cause of mortality and morbidity, for novel antiarrhythmic therapies. This study states that the first report of sophoridine (SPN), a quinolizidine alkaloid derived from traditional Chinese herbs, shows promise as a potential candidate due to its anti-arrhythmic and antioxidant properties. The study found that cell viability in H9C2 rat cardiomyocytes remained stable even when treated with SPN at a higher dosage of 100 μg/ml. This phenomenon was accompanied by increases in mitochondria-derived reactive oxygen species (ROS) and calcium/calmodulin-dependent protein kinase II (CaMKII) signaling, at 50 and 100 μg/ml. Glucose fluctuations regulate ventricular arrhythmias caused by SPN by activating the ROS/CaMKII pathway. Experimental models using zebrafish provided additional evidence supporting the regulatory effects of SPN on heart rate. In addition, the administration of SPN resulted in substantial deregulation of crucial genes involved in heart development (nppa, nppb, tnnt2a) at the transcriptional level in zebrafish. These findings provide insight into the various pharmacological properties of SPN and this opens up new possibilities for anti-arrhythmic treatment strategies.

Imatinib‑ and ponatinib‑mediated cardiotoxicity in zebrafish embryos and H9c2 cardiomyoblasts.

Tyrosine kinase inhibitors (TKIs) offer targeted therapy for cancers but can cause severe cardiotoxicities. Determining their dose‑dependent impact on cardiac function is required to optimize therapy and minimize adverse effects. The dose‑dependent cardiotoxic effects of two TKIs, imatinib and ponatinib, were assessed in vitro using H9c2 cardiomyoblasts and in vivo using zebrafish embryos. In vitro, H9c2 cardiomyocyte viability, apoptosis, size, and surface area were evaluated to assess the impact on cellular health. In vivo, zebrafish embryos were analyzed for heart rate, blood flow velocity, and morphological malformations to determine functional and structural changes. Additionally, reverse transcription‑quantitative PCR (RT‑qPCR) was employed to measure the gene expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), established markers of cardiac injury. This comprehensive approach, utilizing both in vitro and in vivo models alongside functional and molecular analyses, provides a robust assessment of the potential cardiotoxic effects. TKI exposure decreased viability and surface area in H9c2 cells in a dose‑dependent manner. Similarly, zebrafish embryos exposed to TKIs exhibited dose‑dependent heart malformation. Both TKIs upregulated ANP and BNP expression, indicating heart injury. The present study demonstrated dose‑dependent cardiotoxic effects of imatinib and ponatinib in H9c2 cells and zebrafish models. These findings emphasize the importance of tailoring TKI dosage to minimize cardiac risks while maintaining therapeutic efficacy. Future research should explore the underlying mechanisms and potential mitigation strategies of TKI‑induced cardiotoxicities.

Abstract We122: Suppression of defender against cell death 1 (Dad1) induces cardiomyocyte death by regulating cell adhesion proteins.

Introduction: Suppression of cardiomyocyte loss is considered a promising strategy for the prevention of the onset of heart failure (HF). Previously, defender against cell death 1 ( Dad1 ) was identified as a cytoprotective gene. Dad1 forms a complex with staurosporine and temperature sensitive 3A (Stt3A), a catalytic subunit of oligosaccharyltransferase (OST) complex which is responsible for N-glycosylation. However, the function of Dad1 in cardiomyocytes remains unknown. Hypothesis: The disruption of cell-extracellular matrix interactions results in cell death, known as anoikis. Because various cell adhesion proteins are N-glycosylated, we hypothesized that Dad1 suppressed anoikis by regulating N-glycosylation of cell adhesion proteins in cardiomyocytes. Methods: Neonatal rat cardiomyocytes were cultured and the expression of Dad1 or Stt3A was knocked down using siRNA. The protein expression was assessed with immunoblot analysis, and cell viability was evaluated using a CellTiter-Blue assay kit. Results: The suppression of Dad1 using siRNAs reduced cardiomyocyte viability ( p &lt;0.01, n=4). Interestingly, suppression of Dad1 impaired the N-glycosylation of integrin β1 and decreased the expression of mature integrin β1 ( p &lt;0.01, n=3). These changes inactivated integrin-mediated signal transduction through dephosphorylation of focal adhesion kinase ( p &lt;0.01, n=5). In addition, enhanced cell-extracellular matrix interactions by using adhesamine rescued the cardiomyocyte death by Dad1 knockdown ( p &lt;0.01, n=4). Next, we pursued the relationship between Dad1 and Stt3A. Dad1 knockdown decreased the expression of Stt3A ( p &lt;0.01, n=6). Suppression of Stt3A induced cardiomyocyte death accompanied by the changes of cell adhesion proteins ( p &lt;0.01, n=4). Finally, double knockdown of Dad1 and Stt3A did not induce a further reduction in cell viability compared with the knockdown of only Dad1 ( p &lt;0.05, n=4), suggesting that cardiomyocyte death by Dad1 knockdown was dependent on Stt3A. Conclusion: Dad1 is required for the stabilization of Stt3A and suppresses cardiomyocyte anoikis by regulating N-glycosylation of cell adhesion proteins in an OST-dependent manner. Dad1-mediated cardiomyocyte survival could be a therapeutic target against HF.

Ginsenoside Rg1 induces ferroptosis by regulating the focal adhesion kinase/protein kinase B-forkhead box O3A signaling pathway and alleviates sepsis-induced myocardial damage.

It is significant to note that 50% of patients with sepsis show cardiac insufficiency. Ginsenoside-Rg1 (G-Rg1) has been shown to have a cardiovascular protective effect. However, whether G-Rg1 is involved in the mechanism of action of sepsis-induced myocardial damage (SIMD) is unclear. This study aimed to investigate the protective effect of G-Rg1 on SIMD and to further investigate its mechanism and mechanisms of regulation of downstream pathways. An in vivo model of sepsis was established in mice by cecal ligation and puncture (CLP), and mice was administered intraperitoneally 35 or 70 mg/kg G-Rg1 after surgery. The damage to cardiac tissue was detected by hematoxylin and eosin (HE) staining. Forkhead transcription factor O subfamily member 3a (FOXO3A) in SIMD mice was detected by immunohistochemistry. Apoptosis in mouse myocardial tissue was determined by TUNEL staining. The effect of G-Rg1 on SIMD cardiomyocytes was evaluated by incubating the cells with lipopolysaccharide to induce inflammation as an in vitro model of SIMD. Cardiomyocyte viability and apoptosis were evaluated by cell counting kit-8 (CCK-8) and flow cytometry. Lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB), cardiac troponin I (cTnI), and Fe2+ markers of heart damage were detected by the kit. The concentrations of tumor necrosis factor alpha (TNF-α) and interleukin-1beta (IL-1β) in heart tissue and H9c2 cells were determined by ELISA. The factors related to the focal adhesion kinase (FAK)/protein kinase B (AKT)-FOXO3A signaling pathway were determined by RT-qPCR and Western blot. High-dose G-Rg1 had a significant inhibitory effect on SIMD mouse model and lipopolysaccharide (LPS)-induced H9c2 cardiomyocytes, reducing serum levels of LDH, CK-MB, and cTnI concentrations, which effectively alleviated SIMD. G-Rg1 restored the abnormally elevated levels of TNF-α, IL-1β, and iron ions and promoted the expression of anti-apoptotic protein B-cell lymphoma 2 (Bcl-2) expression, inhibiting apoptosis and inflammatory responses. In addition, G-Rg1 reversed the inhibitory effect of G-Rg1 on LPS-induced H9c2 cardiomyocyte injury through activation of the FAK/AKT signaling pathway and up-regulation of FOXO3A. G-Rg1 promoted the activation of the FAK/AKT signalling pathway and up-regulation of the protein expression levels of pathway-associated proteins, p-FAK and p-AKT. Therefore, G-Rg1 mediated the FAK/AKT-FOXO3A signaling pathway and played a role in the treatment of SIMD. We conclude that G-Rg1 inhibited apoptosis and inflammation of cardiomyocytes induced by sepsis and reduced iron ion levels by regulating FAK/AKT-FOXO3A signaling pathway.

Apigenin Attenuates Transverse Aortic Constriction-Induced Myocardial Hypertrophy: The Key Role of miR-185-5p/SREBP2-Mediated Autophagy.

Apigenin is a natural flavonoid compound with promising potential for the attenuation of myocardial hypertrophy (MH). The compound can also modulate the expression of miR-185-5p that both promote MH and suppress autophagy. The current attempts to explain the anti-MH effect of apigenin by focusing on changes in miR-185-5p-mediated autophagy. Hypertrophic symptoms were induced in rats using transverse aortic constriction (TAC) method and in cardiomyocytes using Ang II and then handled with apigenin. Changes in myocardial function and structure and cell viability and surface area were measured. The role of miR-185-5p in the anti-MH function of apigenin was explored by detecting changes in autophagic processes and miR-185-5p/SREBP2 axis. TAC surgery induced weight increase, structure destruction, and collagen deposition in hearts of model rats. Ang II suppresses cardiomyocyte viability and increased cell surface area. All these impairments were attenuated by apigenin and were associated with the restored level of autophagy. At the molecular level, the expression of miR-185-5p was up-regulated by TAC, while the expression of SREBP2 was down-regulated, which was reserved by apigenin both in vivo and in vitro. The induction of miR-185-5p in cardiomyocytes could counteracted the protective effects of apigenin. Collectively, the findings outlined in the current study highlighted that apigenin showed anti-MH effects. The effects were related to the inhibition of miR-185-5p and activation of SREBP, which contributed to the increased autophagy.

Gastrodin exerts perioperative myocardial protection by improving mitophagy through the PINK1/Parkin pathway to reduce myocardial ischemia-reperfusion injury

BackgroundAlthough blood flow is restored after treatment of myocardial infarction (MI), myocardial ischemia and reperfusion (I/R) can cause cardiac injury, which is a leading cause of heart failure. Gastrodin (GAS) exerts protective effects against brain, heart, and kidney I/R. However, its pharmacological mechanism in myocardial I/R injury (MIRI) remains unclear. PurposeGAS regulates autophagy in various diseases, such as acute hepatitis, vascular dementia, and stroke. We hypothesized that GAS could repair mitochondrial damage and regulate autophagy to protect against MIRI. Study designMale C57BL/6 mice and H9C2 cells were subjected to I/R and hypoxia-reoxygenation (H/R) injury after GAS administration, respectively, to assess the impact of GAS on cardiomyocyte phenotypes, heart, and mitochondrial structure and function. The effect of GAS on cardiac function and mitochondrial structure in patients undergoing cardiac surgery has been observed in clinical practice. MethodsThe effects of GAS on cardiac structure and function, mitochondrial structure, and expression of related molecules in an animal model of MIRI were evaluated using immunohistochemical staining, enzyme-linked immunosorbent assay (ELISA), transmission electron microscopy, western blotting, and gene sequencing. Its effects on the morphological, molecular, and functional phenotypes of cardiomyocytes undergoing H/R were observed using immunohistochemical staining, real-time quantitative PCR, and western blotting. ResultsGAS significantly reduces myocardial infarct size and improves cardiac function in MIRI mice in animal models and increases cardiomyocyte viability and reduces cardiomyocyte damage in cellular models. In clinical practice, myocardial injury was alleviated with better cardiac function in patients undergoing cardiac surgery after the application of GAS; improvements in mitochondria and autophagy activation were also observed. GAS primarily exerts cardioprotective effects through activation of the PINK1/Parkin pathway, which promotes mitochondrial autophagy to clear damaged mitochondria. ConclusionGAS can promote mitophagy and preserve mitochondria through PINK1/Parkin, thus indicating its tremendous potential as an effective perioperative myocardial protective agent.

An infusible biologically active adhesive for chemotherapy-related heart failure in elderly rats

Chemotherapy-induced cardiotoxicity with subsequent heart failure (HF) is a major cause of morbidity and mortality in cancer survivors worldwide. Chemotherapy-induced HF is exceptionally challenging as it generally manifests in patients who are typically not eligible for left ventricular device implantation or heart transplantation. To explore alternative treatment strategies for cancer survivors suffering from chemotherapy-induced HF, we developed a minimally invasive infusible cardiac stromal cell secretomes adhesive (MISA) that could be delivered locally through an endoscope-guided intrapericardial injection. To mimic the typical clinical presentation of chemotherapy-induced HF in elder patients, we established an aged rat model in which restrictive cardiomyopathy with sequential HF was induced via consecutive doxorubicin injections. In vitro, we prove that MISA not only enhanced cardiomyocytes proliferation potency and viability, but also inhibited their apoptosis. In vivo, we prove that MISA improved the ventricular contractility indexes and led to beneficial effects on histological and structural features of restrictive cardiomyopathy via promoting cardiomyocyte proliferation, angiogenesis, and mitochondrial respiration. Additionally, we also evaluated the safety and feasibility of MISA intrapericardial delivery in a healthy porcine model with an intact immune system. In general, our data indicates that MISA has a strong potential for translation into large animal models and ultimately clinical applications for chemotherapy-induced HF prior to the final option of heart transplantation.

Tyrosine Kinase Inhibitor Lenvatinib Causes Cardiotoxicity by Inducing Endoplasmic Reticulum Stress and Apoptosis through Activating ATF6, IRE1α and PERK Signaling Pathways.

Lenvatinib is a tyrosine kinase inhibitor that can improve progression-free survival in patients with thyroid cancer and hepatocellular carcinoma. However, it is limited by adverse cardiovascular events, including hypertension and cardiac dysfunction. Activation of endoplasmic reticulum stress is involved in cardiomyocyte apoptosis. This study aimed to confirm whether the cardiotoxicity of lenvatinib is associated with endoplasmic reticulum stress by targeting the activating transcription factor 6 (ATF6), inositol- requiring enzyme 1α (IRE1α) and protein kinase RNA-like ER kinase (PERK) signaling pathways. Male C57/BL6 mice were intragastric administration with 30 mg/kg/day lenvatinib. Electrocardiography (ECG) and echocardiography were used to detect arrhythmias and cardiac function. Neonatal rat cardiomyocytes were treated with lenvatinib for 48h. Cell counting kit (CCK8), 2´,7´-dichlorodihydrofluoresceine diacetate (H2DCFHDA), Hoechst 33258 and dihydrorhodamine 123 were respectively used for evaluating cell viability, the level of reactive oxygen species (ROS), nuclear morphological changes and mitochondrial membrane potential (MMP) level. Lenvatinib remarkably decreased the posterior wall thickness of left ventricle during diastole and systole but caused little decrease to the left ventricular ejection fraction (LVEF, %). Furthermore, lenvatinib greatly prolonged the corrected QT interval (QTc) and altered the morphology of cardiomyocytes. No dramatic difference in fibrosis was found in mouse cardiac slices. Lenvatinib upregulates apoptosis-related protein expression. In addition, lenvatinib increased ERS-related protein expression (GRP78, CHOP, and ATF6) and enhanced PERK phosphorylation. In neonatal rat cardiac myocytes, lenvatinib markedly decreased the viability of cardiomyocytes and induced apoptosis. Furthermore, ROS production increased and MMP decreased. Similar to the mice experiment, lenvatinib caused upregulation of apoptosis-related and ERS-related proteins and increased the phosphorylation levels of PERK and IRE1α. Lenvatinib-induced cardiotoxicity is associated with ERS-induced apoptosis by targeting the ATF6, IRE1α, and PERK signaling pathways.

Exposure to serum from exclusive heated tobacco product smokers induces mTOR activation and fibrotic features in human cardiac stromal cells

Chronic smokers have increased risk of fibrosis-related atrial fibrillation. The use of heated-tobacco products (HTPs) is increasing exponentially, and their health impact is still uncertain. We aim to investigate the effects of circulating molecules in exclusive HTP chronic smokers on the fibrotic behavior of human atrial cardiac stromal cells (CSCs). CSCs were isolated from atrial tissue of elective cardiac surgery patients, and exposed to serum lots from young healthy subjects, stratified in exclusive HTP smokers, tobacco combustion cigarette (TCC) smokers, or nonsmokers (NS). CSCs treated with TCC serum displayed impaired migration and increased expression of pro-inflammatory cytokines. Cells cultured with HTP serum showed increased levels of pro-fibrotic markers, and reduced expression of connexin-43. Both TCC and HTP sera increased collagen release and reduced secretion of angiogenic protective factors from CSCs, compared to NS serum. Paracrine support to tube-formation by endothelial cells and to viability of cardiomyocytes was significantly impaired. Treatment with sera of both smokers groups impaired H2O2/NO release balance by CSCs and reduced early phosphorylation of several pathways compared to NS serum, leading to mTOR activation. Cotreatment with rapamycin was able to reduce mTOR phosphorylation and differentiation into aSMA-positive myofibroblasts in CSCs exposed to TCC and HTP sera. In conclusion, the circulating molecules in the serum of chronic exclusive HTP smokers induce fibrotic behavior in CSCs through activation of the mTOR pathway, and reduce their beneficial paracrine effects on endothelial cells and cardiomyocytes. These results point to a potential risk for cardiac fibrosis in chronic HTP users.