Cardiomyocyte Viability Research Articles

SS-31@Fer-1 Alleviates ferroptosis in hypoxia/reoxygenation cardiomyocytes via mitochondrial targeting.

Targeting mitochondrial ferroptosis presents a promising strategy for mitigating myocardial ischemia-reperfusion (I/R) injury. This study aims to evaluate the efficacy of the mitochondrial-targeted ferroptosis inhibitor SS-31@Fer-1 (elamipretide@ferrostatin1) in reducing myocardial I/R injury. SS-31@Fer-1 was synthesized and applied to H9C2 cells subjected to hypoxia/reoxygenation (H/R) to assess its protective effects. Cytotoxicity was evaluated using a cell counting kit-8 (CCK-8) assay, with lactate dehydrogenase (LDH) and creatine kinase isoenzyme (CK-MB) levels measured. Mitochondrial reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were assessed using Mito-SOX and JC-1 fluorescent dyes, respectively. Lipid peroxidation products, malondialdehyde (MDA) and glutathione (GSH), were quantified. Mitochondrial structure, mt-cytochrome b (mt-Cytb), and mt-ATP synthase membrane subunit 6 (mt-ATP6) were analyzed. Additionally, iron homeostasis and ferroptosis markers were evaluated. SS-31@Fer-1 significantly improved H/R-induced cardiomyocyte viability and reduced LDH and CK-MB levels. Compared to the Fer-1 group, SS-31@Fer-1 reduced GSH and increased MDA levels, enhancing mitochondrial integrity and function. Notably, it increased mitochondrial ROS and decreased MMP, indicating a mitigation of H/R-induced cardiomyocyte cytotoxicity. Furthermore, SS-31@Fer-1 maintained cellular iron homeostasis, as evidenced by increased expression of FTH, FTMT, FPN, and ABCB8. Elevated levels of GPX4 and Nrf2 were observed, while ACSL4 and PTGS2 levels were reduced in the SS-31@Fer-1 group. SS-31@Fer-1 effectively suppressed ferroptosis in H/R-induced cardiomyocytes by maintaining cellular iron homeostasis, improving mitochondrial function, and inhibiting oxidative stress. These findings provide novel insights and opportunities for alleviating myocardial I/R injury.

Thermosensitive Porcine Myocardial Extracellular Matrix Hydrogel Coupled with Proanthocyanidins for Cardiac Tissue Engineering.

Currently, there are no therapies that prevent the negative myocardial remodeling process that occurs after a heart attack. Injectable hydrogels are a treatment option because they may replace the damaged extracellular matrix and, in addition, can be administered minimally invasively. Reactive oxygen species generated by ischemia-reperfusion damage can limit the therapeutic efficacy of injectable hydrogels. In order to overcome this limitation, grape seed proanthocyanidins were incorporated as antioxidant compounds into a thermosensitive myocardial extracellular matrix hydrogel in this study. For the fabrication of the hydrogel, the extracellular matrix obtained by decellularization of porcine myocardium was solubilized through enzymatic digestion, and the proanthocyanidins were incorporated. After exposing this extracellular matrix solution to 37 °C, it self-assembled into a hydrogel with a porous structure. According to the physicochemical and biological evaluation, the coupling of proanthocyanidins in the hydrogel has a positive effect on the antioxidant capacity, gelation kinetics, in vitro degradation, and cardiomyocyte viability, indicating that the hydrogel coupled with this type of antioxidants represents a promising alternative for potential application in post-infarction myocardial regeneration. Furthermore, this study proposes the best concentrations of proanthocyanidins that resulted in the hydrogels for future studies in cardiac tissue engineering.

Suppression of Dad1 induces cardiomyocyte death by weakening cell adhesion.

As cardiomyocyte loss causes heart failure, inhibition of cardiomyocyte death may be a therapeutic strategy against heart failure. In this study, we have identified defender against cell death 1 (Dad1) as a candidate regulator of cardiomyocyte death, using complementary DNA microarray and siRNA knockdown screening. Dad1 is a subunit of oligosaccharyltransferase (OST) complex that is responsible for protein N-glycosylation; however, its function in cardiomyocytes remains unknown. Importantly, the knockdown of Dad1 using siRNA reduced the viability of neonatal rat cardiomyocytes (NRCMs), accompanied by cleaved caspase3 expression, independent of endoplasmic reticulum stress. Dad1 knockdown impaired cell spreading and reduced myofibrillogenesis in NRCMs, suggesting that Dad1 knockdown induced anoikis, apoptosis by disrupting cell-matrix interactions. Consistently, knockdown of Dad1 impaired N-glycosylation of integrins α5 and β1, accompanied by inactivation of focal adhesion kinase. When cell adhesion was enhanced using adhesamine, fibronectin, or collagen type IV, cardiomyocyte death induced by Dad1 knockdown was reduced. Dad1 knockdown decreased the expression of staurosporine and temperature-sensitive 3 A (Stt3A), a catalytic subunit of OST complex. Interestingly, Stt3A knockdown using Stt3A siRNA reduced the expression of Dad1, indicating that both Dad1 and Stt3A were required for OST stabilization. In conclusion, Dad1 plays an important role in maintaining the expression of mature N-glycosylated integrins and their downstream signaling molecules to suppress cardiomyocyte anoikis.NEW & NOTEWORTHY This study found for the first time that the knockdown of Dad1 induced cardiomyocyte death, accompanied by impairment of myofibrillogenesis and cell spreading. Dad1 regulates the N-glycosylation of integrins in cooperation with Stt3A and preserves cell adhesion activity, promoting cardiomyocyte survival. This is the first demonstration that Dad1 contributes to the maintenance of cardiac homeostasis through the posttranslational modification of integrins, providing a novel insight into the biological significance of OST complex in cardiomyocytes.

Protective effects of phosphocreatine against Doxorubicin-Induced cardiotoxicity through mitochondrial function enhancement and apoptosis suppression via AMPK/PGC-1α signaling pathway.

Doxorubicin (DOX), a potent chemotherapy drug, is limited by its cardiotoxic effects, which can lead to heart damage. This study explores the cardioprotective potential of Phosphocreatine (PCr) in vitro and in vivo models, focusing on its impact on the AMPK and PGC-1α pathways, apoptosis reduction, and mitochondrial function preservation. Advanced methodologies, including high-resolution respirometry (HRR), were employed to assess mitochondrial bioenergetics, AMPK activity, and apoptotic rates in cardiomyocytes. Electrocardiography (ECG) and echocardiography (echo) were used to monitor cardiac function in vivo. Results showed that PCr significantly activated the AMPK and PGC-1α pathways, reduced apoptosis, and stabilized mitochondrial function in cardiomyocytes exposed to DOX. There was an upregulation of AMPK and PGC-1α target genes, stabilization of mitochondrial membranes, and improvements in cellular energy production and antioxidant defenses. PCr also markedly reduced apoptotic markers, enhancing cardiomyocyte viability. ECG and echocardiography revealed that PCr preserved cardiac function, indicated by improved heart rate variability, reduced QT interval prolongation, and enhanced ejection fraction. These findings highlight PCr's potential in mitigating DOX-induced cardiotoxicity by enhancing mitochondrial function and reducing apoptosis. The study underscores the promise of PCr as an agent to reduce chemotherapy-related cardiac injuries, paving the way for further research to improve patient outcomes in cancer treatment.

Of cells and tissues: Identifying the elements of a diabetic cardiac in vitro study model.

This study aimed to elucidate the impact of advanced glycation end products (AGEs) and glucose shock on cardiomyocyte viability, gene expression, cardiac biomarkers, and cardiac contractility. Firstly, AGEs were generated in-house, and their concentration was confirmed using absorbance measurements. AC16 cardiomyocytes were then exposed to varying doses of AGEs, resulting in dose-dependent decreases in cell viability. The maximum tolerated dose of AGEs was determined, revealing significant downregulation of the cardiac gene gap junction alpha 1 (GJA1). Furthermore, the study assessed the effects of AGEs, glucose shock, and their combination on biomarkers, cardiac myosin heavy chain (MHC), and connexin-43 (Cx-43) in AC16 cells. It was found that AGEs supplementation induced an increase in MHC expression while reducing Cx-43 expression, potentially contributing to cardiac dysfunction. Glucose shock also affected cardiomyocyte contractility, highlighting the complex interplay between AGEs, glucose levels, and cardiac function. Additionally, human iPSC-derived cardiomyocytes were subjected to varying doses of AGEs, revealing dose-dependent cytotoxicity and alterations in contractility. Immunostaining confirmed upregulation of MYH7, a cardiac gene associated with muscle contraction, in response to AGEs. However, the expression of Cx-43 was minimal in these cells. This comprehensive investigation sheds light on the intricate relationship between AGEs, glucose shock, and cardiomyocyte function, providing insights into potential mechanisms underlying cardiac dysfunction associated with metabolic disorders such as diabetic cardiomyopathy (DCM).

LncRNA TUG1 Knockdown Reduces Cardiomyocyte Damage in Viral Myocarditis by Targeting the miR-140-3p/CXCL8 Axis.

The purpose of this study was to probe the specific role of long noncoding RNA taurine upregulation 1 (LncRNA TUG1) in viral myocarditis (VMC). The mouse model of VMC was induced by Coxsackievirus type B3 (CVB3). LncRNA TUG1 was subsequently silenced, and micro-140-3p (miR-140-3p) was overexpressed in VMC mice. GenePharma synthesized wild-type and mutant LncRNA TUG1 or CXCL8 (C-X-C Motif Chemokine Ligand 8, Interleukin-8) fragments containing the miR-140-3p binding site and cloned them into the pmirGLO luciferase reporter vector. Dual luciferase reporter assays were performed to test the activity of LncRNA TUG1 or CXCL8 fragments containing miR-140-3p mimic and mimic NC. The effects of silencing LncRNA TUG1 on cell proliferation, apoptosis, and inflammation in the VMC mouse model and in vitro were investigated by flow cytometry, enzyme linked immunosorbent assay, and western blot. In the VMC mouse model, LncRNA TUG1 and CXCL8 were upregulated, while miR-140-3p was downregulated. Suppressing LncRNA TUG1 led to inhibition of CXCL8 by promoting miR-140-3p. Suppressing LncRNA TUG1 or CXCL8 or restoring miR-140-3p were observed to increase cell viability and decrease apoptosis rate of cardiomyocytes. LncRNA TUG1 knockdown suppresses inflammation and damage of VMC cardiomyocytes via the miR-140-3p/CXCL8 axis.

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

Septic 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. Septic 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. In 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. BBR improves septic cardiomyopathy by modulating Notch1 signaling to protect myocardial mitochondria.

Phosphoglycerate mutase 1-mediated dephosphorylation and degradation of Dusp1 disrupt mitochondrial quality control and exacerbate endotoxemia-induced myocardial dysfunction.

Rationale: Endotoxemia, caused by lipopolysaccharides, triggers systemic inflammation and myocardial injury by disrupting mitochondrial homeostasis. This study examines the roles of dual specificity phosphatase 1 (Dusp1) and phosphoglycerate mutase family member 1 (Pgam1) in this process. Methods: This study utilized cardiomyocyte-specific Dusp1 knockout (Dusp1Cko ) and transgenic (Dusp1Tg ) mice, alongside Pgam1 knockout (Pgam1Cko ) mice, subjected to LPS-induced endotoxemia. Echocardiography was performed to assess cardiac function. Mitochondrial integrity was evaluated using molecular techniques, including qPCR and Seahorse assays. Additionally, molecular docking studies and Western blot analyses were conducted to explore the interaction between Pgam1 and Dusp1. Results: Using single-cell sequencing and human sample databases, Dusp1 emerged as a novel biomarker for endotoxemia-induced myocardial dysfunction. Experiments with cardiomyocyte-specific Dusp1 knockout (Dusp1Cko ) and Dusp1 transgenic (Dusp1Tg ) mice showed that Dusp1 deficiency worsens, while overexpression improves, heart function during LPS-induced myocardial injury. This effect is mediated by regulating inflammation and cardiomyocyte viability. Molecular analyses revealed that LPS exposure leads to Dusp1 dephosphorylation at Ser364, increasing its degradation. Stabilizing Dusp1 phosphorylation enhances mitochondrial function through mitochondrial quality control (MQC), including dynamics, mitophagy, and biogenesis. Functional studies identified Pgam1 as an upstream phosphatase interacting with Dusp1. Pgam1 ablation reduced LPS-induced cardiomyocyte dysfunction and mitochondrial disorder. Conclusions: Pgam1-mediated dephosphorylation of Dusp1 disrupts mitochondrial quality control, leading to myocardial dysfunction in endotoxemia. Targeting the Pgam1-Dusp1 axis represents a promising therapeutic strategy for improving cardiac outcomes in patients with endotoxemia.

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.