Mechanisms of myocardial ischemia–reperfusion injury and the cytoprotective role of minocycline: scope and limitations

Exploring the pharmacological versatility of ficus carica: Modulating classical immunometabolism and beyond

The burden of metabolic disorders is alarmingly increasing globally. On the other hand, sustainability is the key project of the 21st century. Natural products offer a coherent option for the complementary management of both these challenges. Ficus carica (FC), commonly known as the fig fruit, has an experimentally proven potency for the modulation of cell cycle, immunity, inflammation, metabolism, and oxidative stress. Here, we review the potential of FC-derived products (FCDP) in slowing down the progression of cancers, acute/chronic inflammation-related conditions, infections, metabolic disorders, toxicities, neurological and neuromuscular diseases, gastrointestinal disorders, vascular diseases, and skin-stressing conditions, as well as, in boosting normal healthy functions of the endocrine, immune, metabolic, and nervous systems. It reveals a variety of cellular and molecular targets for FCDP: cytokines (TNF-α, IL-1β, IL-6, IL-10, IL-12, IL-18, IFN-γ), chemokines (CCL2), other inflammatory mediators (CRP, PGE2), immune receptors (TLR-2, TLR-4, FcεRI), oxidative stress-related markers (SOD, GSH, MDA, GPx, catalase, ROS, NO, protein carbonyls), kinases (MAPKs, hexokinase, G6Pase, FBPase, PEPCK, Akt, AMPK, GSK3, CDKs), other enzymes (COX-2, iNOS, MMPs, caspases), growth factors/receptors (VEGF, EGFR), hormones (DHEAS, prolactin, GnRH, FSH, LH, estradiol, DHT, insulin), cell death-related markers (Bcl-2, Bax, Bak, FasL, gasdermins, cytochrome C), glucose transporter protein (Glut4), and transcription factors (NF-κB, HNF-4α, Foxo, PGC-1α, PPAR-γ, C/EBP-α, CREB, NFATC1, STAT3). FCDP cause both activation and inhibition of AMPK, MAPK, and NF-κB signaling to confer condition-specific advantages. Such a broad-range activity might be attributed to different mechanisms of action of FCDP in modulating functions within the classical immunometabolic system, but also beyond.

The role of Vav3 expression for inflammation and cell death during experimental myocardial infarction

OBJECTIVES

Myocardial Infarction (MI) is the leading cause of chronic heart failure. Previous studies have suggested that Vav3, a receptor protein tyrosine kinase signal transducer, is associated with a variety of cellular signaling processes such as cell morphology regulation and cell transformation with oncogenic activity. However, the mechanism of Vav3-mediated MI development requires further investigation.

METHOD

Here, The authors established an MI rat model by ligating the anterior descending branch of the left coronary artery, and an MI cell model by treating cardiomyocytes with H2O2. Microarray analysis was conducted to identify genes with differential expression in heart tissues relevant to MI occurrence and development. Vav3 was thus selected for further investigation.

RESULTS

Vav3 downregulation was observed in MI heart tissue and H2O2-treated cardiomyocytes. Administration of Lentiviral Vav3 (LV-VAV3) in MI rats upregulated Vav3 expression in MI heart tissue. Restoration of Vav3 expression reduced infarct area and ameliorated cardiac function in MI rats. Cardiac inflammation, apoptosis, and upregulation of NFκB signal in heart tissue of MI animals were assessed using ELISA, TUNEL staining, real-time PCR, and WB. Vav3 overexpression reduced cardiac inflammation and apoptosis and inhibited NFκB expression and activation. Betulinic Acid (BA) was then used to re-activate NFκB in Vav3-overexpressed and H2O2-induced cardiomyocytes. The expression of P50 and P65, as well as nuclear P65, was significantly increased by BA exposure.

CONCLUSIONS

Vav3 might serve as a target to reduce ischemia damage by suppressing the inflammation and apoptosis of cardiomyocytes.

Effect of tanshinone IIA for myocardial ischemia/reperfusion injury in animal model: preclinical evidence and possible mechanisms

Introduction: Tanshinone IIA (Tan IIA), the major active lipophilic ingredient of Radix Salviae Miltiorrhizae, exerts various therapeutic effects on the cardiovascular system. We aimed to identify the preclinical evidence and possible mechanisms of Tan IIA as a cardioprotective agent in the treatment of myocardial ischemia/reperfusion injury. Methods: The study quality scores of twenty-eight eligible studies and data analyses were separately assessed using the CAMARADES 10-item checklist and Rev-Man 5.3 software. Results: The study quality score ranged from 3/10 to 7/10 points. The present study provided preliminary preclinical evidence that Tan IIA could significantly decrease the myocardial infarct size, cardiac enzyme activity and troponin levels compared with those in the control group (p < 0.05). Discussion: Tan IIA alleviated myocardial I/R injury via antioxidant, anti-inflammatory, anti-apoptosis mechanisms and improved circulation and energy metabolism. Thus, Tan IIA is a promising cardioprotective agent for the treatment of myocardial ischemia/reperfusion injury and should be further investigated in clinical trials.

β-catenin ameliorates myocardial infarction by preventing YAP-associated apoptosis

OBJECTIVE

To explore whether the effect of β-catenin on MI and MI-induced cardiomyocyte apoptosis is YAP-dependent.

METHODS

The authors established an MI rat model by ligating the anterior descending branch of the left coronary artery, and an MI cell model by treating cardiomyocytes with H2O2.

RESULTS

β-catenin downregulation was observed in MI cardiac tissues and in H2O2-treated cardiomyocytes. Lentiviral-CTNNB1 was administered to MI rats to upregulate β-catenin expression in MI cardiac tissue. β-catenin recovery reduced the myocardial infarct area, fibrosis, and apoptotic cell death in MI rats. H2O2 treatment attenuated cell viability and induced cell death in cardiomyocytes, whereas β-catenin overexpression partially reversed these changes. Moreover, H2O2 treatment caused the deactivation of Yes-Associated Protein (YAP), as detected by increased YAP phosphorylation and reduced the nuclear localization of YAP. Upregulation of β-catenin expression reactivated YAP in H2O2-treated cardiomyocytes. Reactivation of YAP was achieved by administration of Mitochonic Acid-5 (MA-5) to H2O2-treated cardiomyocytes, and deactivation of YAP by CIL56 treatment in β-catenin-overexpressing H2O2-treated cardiomyocytes. MA-5 administration increased cell viability and repressed apoptosis in H2O2-treated cardiomyocytes, whereas CIL56 treatment counteracted the effects of β-catenin overexpression on cell survival and apoptosis.

CONCLUSIONS

The present data indicate that β-catenin and YAP are effective treatment targets for MI, blocking the apoptotic death of cardiomyocytes.

Syringin exerts anti-inflammatory and antioxidant effects by regulating SIRT1 signaling in rat and cell models of acute myocardial infarction

INTRODUCTION

This study aimed to investigate the role of syringin in improving heart function during myocardial ischemia/reperfusion (I/R) and to determine whether the sirtuin 1/peroxisome proliferator-activated receptor gamma coactivator 1 alpha (SIRT1/PGC-1α) pathway contributes to this cardioprotective effect in vivo and in vitro.

METHODS

H9c2 cells were incubated with H₂ O₂ for 12 h. The effect of syringin was assessed by measuring cell viability; the apoptotic rate; Keap1/NRF2/HO-1 activation; and the levels of proinflammatory cytokines, oxidative products, and antioxidative enzymes. In addition, SIRT1 was silenced via short hairpin RNA (shRNA)-SIRT1 transfection to evaluate its involvement in syringin-mediated protection. Syringin rescued cells from H₂ O₂ -induced reductions in viability, antioxidative enzyme levels, and NRF2/HO-1 activation; likewise, syringin inhibited apoptosis, inflammation, and oxidative stress. We also created a rat model of I/R by ligating the left anterior descending coronary artery for 30 min, followed by reperfusion for 12 min. Syringin was then intraperitoneally injected, and the effect on infarct size and cardiac function was examined after 7 days. NRF2/HO-1 activity and the levels of myocardial proinflammatory cytokines, oxidative products, and antioxidative enzymes were measured.

RESULTS

In comparison to the untreated I/R group, the syringin treatment group exhibited improved cardiac function and reduced cardiac lesion and infarct size. Syringin administration also markedly reduced the levels of proinflammatory cytokines and reactive oxygen species and promoted antioxidative enzyme expression and NRF2/HO-1 pathway activation.

CONCLUSIONS

Syringin may serve a protective role in animal and cell models of I/R by improving cardiac function, inhibiting the inflammatory response, and activating the antioxidative response.

Reperfusion injury in acute ischemic stroke: Tackling the irony of revascularization

Reperfusion injury is an unfortunate consequence of restoring blood flow to tissue after a period of ischemia. This phenomenon can occur in any organ, although it has been best studied in cardiac cells. Based on cardiovascular studies, neuroprotective strategies have been developed. The molecular biology of reperfusion injury remains to be fully elucidated involving several mechanisms, however these mechanisms all converge on a similar final common pathway: blood brain barrier disruption. This results in an inflammatory cascade that ultimately leads to a loss of cerebral autoregulation and clinical worsening. In this article, the authors present an overview of these mechanisms and the current strategies being employed to minimize injury after restoration of blood flow to compromised cerebral territories.

Integrated chemical profiling, network pharmacology and pharmacological evaluation to explore the potential mechanism of Xinbao pill against myocardial ischaemia-reperfusion injury

CONTEXT

Xinbao pill (XBW), a traditional Chinese herbal formula, is widely used in clinical treatment for cardiovascular diseases; however, the therapeutic effect of XBW on myocardial ischaemia-reperfusion injury (MI/RI) is unclear.

OBJECTIVE

This study evaluates the cardioprotective effect and molecular mechanism of XBW against MI/RI.

MATERIALS AND METHODS

A phytochemistry-based network pharmacology analysis was used to uncover the mechanism of XBW against MI/RI. Ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry method was used to identify chemicals. MI/RI-related targets of XBW were predicted using TargetNet database, OMIC database, etc. Sprague-Dawley (SD) rats under anterior descending artery ligation model were divided into Sham, MI/RI and XBW (180 mg/kg, intragastric administration). After 30 min ischaemia and 24 h reperfusion, heart tissues were collected for measurement of myocardial infarct size. After oxygen glucose deprivation for 6 h, H9c2 cells were treated with XBW (60, 240 and 720 μg/mL) and diazoxide (100 μM) for 18 h of reperfusion.

RESULTS

Thirty-seven chemicals were identified in XBW; 50 MI/RI-related targets of XBW were predicted using indicated databases. XBW significantly reduced infarct size and creatine kinase MB (CK-MB) level after MI/RI; XBW protected H9c2 cells against OGD/R injury. Gene ontology (GO) and KEGG pathway enrichment analyses by String database showed that the cardioprotective effect of XBW was associated with autophagy and apoptosis signalling pathways. Experimental investigation also verified that XBW suppressed apoptosis, autophagy and endoplasmic reticulum (ER) stress.

CONCLUSIONS

XBW showed therapeutic effects against MI/RI mainly via attenuating apoptosis though suppressing excessive autophagy and ER stress.

Hsa_circ_0007059 promotes apoptosis and inflammation in cardiomyocytes during ischemia by targeting microRNA-378 and microRNA-383

Circular RNAs (circRNAs) are a class of non-coding RNA molecules that are associated with not only normal physiological functions but also various diseases, including cardiac diseases such as myocardial infarction (MI). The present study explored the potential role of circRNA_0007059 (circ_0007059) during MI pathogenesis using in vitro studies. Microarray and quantitative PCR analyses demonstrated elevated circ_0007059 expression and downregulated miR-378 and miR-383 expression in H₂O₂-treated mice cardiomyocytes and infarcted hearts of MI mouse model as compared those in relevant controls. Moreover, circ_0007059 knockdown improved cardiomyocyte viability after H₂O₂ treatment as revealed by the CCK-8 and colony formation assays. Flow cytometry and caspase activity assays demonstrated that circ_0007059 suppressed H₂O₂-induced cardiomyocyte apoptosis. Enzyme-linked immunosorbent assays and Western blotting revealed that inflammatory cytokine (interleukin-1β, interleukin-18 and C-C motif chemokine ligand 5) expression was induced by H₂O₂ treatment and that circ_0007059 repressed H₂O₂-induced inflammation. Bioinformatics analyses and dual-luciferase reporter assays showed that circ_0000759 acts as a miR-378 and miR-383 sponge. Furthermore, the upregulation or suppression of miR-378 and miR-383 expression in H₂O₂-treated cardiomyocytes had similar effects on the apoptosis and inflammation of cardiomyocytes as that of circ_0007059 knockdown or overexpression, respectively. Additionally, lentiviral shRNA-circ_0007059 administration to mice with MI considerably reduced the size of infarcted regions and promoted cardiac activity. Collectively, our findings suggest that circ_0007059 expression is upregulated in mice cardiomyocytes in response to oxidative stress and cardiac tissues of MI mouse model, suggesting its involvement in the pathogenesis of MI by targeting miR-378 and miR-383.

Minocycline as heart conditioning agent in experimental type 2 diabetes mellitus - an antibacterial drug in heart protection

Cardiovascular diseases, and among them certainly myocardial infarction, remain leading cause of death worldwide. Diabetes increases risk of occurrence as well as adverse outcome of myocardial infarction. Conditioning maneuvers are the most attractive method for alleviating both the consequences of ischemia and reperfusion. Minocycline is a tetracycline derivative which exerts antioxidant, anti-inflammatory, and anti-apoptotic effects. The aim of this study was to assess the protective ability of preconditioning and postconditioning of isolated hearts from healthy and rats with experimentally induced type 2 diabetes with minocycline on functional recovery and redox status after ischemia and reperfusion. The hearts from healthy and diabetic rats were excised and retrogradely perfused according to the Langendorff technique. Using sensor in the left ventricle, the cardiodynamic parameters were recorded and in the samples of the coronary venous effluent oxidative stress biomarkers were analyzed. Minocycline was injected directly into the coronary vessels, in preconditioning 5 min before global ischemia, and in postconditioning during the first 5 min of reperfusion. Results of this study clearly show beneficial effects of minocycline applied both before ischemia and in the first minutes of reperfusion fashion in both healthy and diabetic rat hearts. The most prominent protective effect regarding oxidative stress is related to the decreased production of superoxide anion radical due postconditioning with minocycline in diabetic hearts. Cardiodynamic parameters were significantly improved in minocycline conditioned groups. Superoxide anion radical stands out as the most susceptible to changes induced by minocycline.

Effect of minocycline on the left ventricular function following ST-elevation myocardial infarction treated by primary percutaneous coronary intervention

BACKGROUND

Cardiac remodeling following myocardial infarction is a pathological process. We aimed to examine the effect of early short-term minocycline on the left ventricular function following ST-elevation myocardial infarction treated by the primary percutaneous coronary intervention.

METHODS

In this double-blind, randomized controlled trial, data of 73 patients STEMI patients who were candidates for primary PCI were enrolled. Patients were then randomized to receive minocycline 50 mg orally, followed by 50 mg once a day for 5 days or a placebo with the same schedule. Measurement of serum matrix metalloproteinase-9 (MMP-9) and 2-dimensional speckle tracking echocardiography was performed at baseline and between 4 and 6 months after discharge. Then the demographic, clinical, echocardiographic, and angiographic data, as well as the levels of MMP-9, were compared between the study groups.

RESULTS

There was no statistically significant difference between the study groups regarding the baseline characteristics. Serum levels of MMP-9 did not change following the intervention within each group and were not significantly different between the groups after follow-up. In the follow-up echocardiography, we also did not observe any difference between the two groups CONCLUSION: In this study, we did not observe any effect of minocycline on cardiac remodeling based on 2-dimensional speckle tracking echocardiography and MMP-9 levels.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials IRCT201411188698N15 . Registered on 22 June 2015, prospectively.

A Cardioplegic Solution with an Understanding of a Cardiochannelopathy

Cardiac surgeries have been improved by accompanying developing cardioplegia solutions. However, the cardioplegia application presents an ongoing challenge with a view of a sufficiently restored cardiac function. In this review, we focus on the cardioplegia-induced mechanism and summarize the findings of studies undertaken to improve cardioprotective strategies. Currently, and somewhat surprisingly, relatively little is known about cardiac electrolyte regulation through channel physiology. We hope that an improved understanding of the electrolyte transport through ion channels/transporters and modulations of water channel aquaporins will provide an insight into cardiac channel physiology and a channel-based cardiac pathology of a cardiochannelopathy.

PTB domain and leucine zipper motif 1 (APPL1) inhibits myocardial ischemia/hypoxia-reperfusion injury via inactivation of apoptotic protease activating factor-1 (APAF-1)/Caspase9 signaling pathway

Myocardial ischemia/hypoxia-reperfusion injury mediates the progression of multiple cardiovascular diseases. It has been reported that knockdown of adaptor protein containing a PH domain, PTB domain and leucine zipper motif 1 (APPL1) is a significant factor for the progression of myocardial injury. However, the role of APPL1 in myocardial ischemia remains unclear. Hence, the aim of the present study was to investigate the specific mechanism underlying the role of APPL1 in myocardial ischemia.In our study, the mRNA level of APPL1 was detected by quantitative real-time PCR (RT-qPCR). The expressions of APPL1, Apoptotic protease activating factor-1 (APAF-1), cleaved caspase9 and other inflammation- and apoptosis-related proteins were determined by western blotting. The secretion of inflammatory cytokines and lactate dehydrogenase (LDH) levels were measured by commercial assay kits. The H9C2 cell viability was analyzed by cell counting kit-8 (CCK-8) assay. The apoptosis rate of H9C2 cells was analyzed by TUNEL assay. The interaction between APPL1 and APAF-1/caspase9 was determined by Immunoprecipitation (IP).Our findings demonstrated that APPL1 was low expressed in myocardial ischemia tissues and cells. APPL1 knockdown suppressed the viability of myocardial ischemia cells and aggravated hypoxia/reperfusion-induced LDH hypersecretion, inflammation and apoptosis. In addition, the overexpression of APPL1 induced inactivation of APAF-1/Caspase9 signaling pathway. Significantly, APAF1 inhibitor reversed the effect of APPL1 knockdown on viability, LDH secretion, inflammation and apoptosis.We conclude that APPL1 inhibits myocardial ischemia/hypoxia-reperfusion injury via inactivation of APAF-1/Caspase9 signaling pathway. Hence, APPL1 may be a novel and effective target for the treatment of myocardial ischemia.

Morphine Prevents Ischemia/Reperfusion-Induced Myocardial Mitochondrial Damage by Activating δ-opioid Receptor/EGFR/ROS Pathway

OBJECTIVE

The purpose of this study was to determine whether the epidermal growth factor receptor (EGFR), which is a classical receptor tyrosine kinase, is involved in the protective effect of morphine against ischemia/reperfusion (I/R)-induced myocardial mitochondrial damage.

METHODS

Isolated rats hearts were subjected to global ischemia followed by reperfusion. Cardiac H9c2 cells were exposed to a simulated ischemia solution followed by Tyrode's solution to induce hypoxia/reoxygenation (H/R) injury. Triphenyltetrazolium chloride (TTC) was used to measure infarct size. The mitochondrial morphological and functional changes were determined using transmission election microscopy (TEM), mitochondrial stress assay, and mitochondrial swelling, respectively. Mitochondrial fluorescence indicator JC-1, DCFH-DA, and Mitosox Red were used to determine mitochondrial membrane potential (△Ψm), intracellular reactive oxygen species (ROS) and mitochondrial superoxide. A TUNUL assay kit was used to detect the level of apoptosis. Western blotting analysis was used to measure the expression of proteins.

RESULTS

Treatment of isolated rat hearts with morphine prevented I/R-induced myocardial mitochondrial injury, which was inhibited by the selective EGFR inhibitor AG1478, suggesting that EGFR is involved in the mitochondrial protective effect of morphine under I/R conditions. In support of this hypothesis, the selective EGFR agonist epidermal growth factor (EGF) reduced mitochondrial morphological and functional damage similarly to morphine. Further study demonstrated that morphine may alleviate I/R-induced cardiac damage by inhibiting autophagy but not apoptosis. Morphine increased protein kinase B (Akt), extracellular regulated protein kinases (ERK) and signal transducer and activator of transcription-3 (STAT-3) phosphorylation, which was inhibited by AG1478, and EGF had similar effects, indicating that morphine may activate Akt, ERK, and STAT-3 via EGFR. Morphine and EGF increased intracellular reactive oxygen species (ROS) generation. This effect of morphine was inhibited by AG1478, indicating that morphine promotes intracellular ROS generation by activating EGFR. However, morphine did not increase ROS generation when cells were transfected with siRNA against EGFR. In addition, EGFR activity was markedly increased by morphine, but the effect of morphine was reversed by naltrindole. These results suggest that morphine may activate EGFR via δ-opioid receptor activation.

CONCLUSIONS

Morphine may prevent I/R-induced myocardial mitochondrial damage by activating EGFR through δ-opioid receptors, in turn increasing RISK and SAFE pathway activity via intracellular ROS. Moreover, morphine may reduce myocardial injury by regulating autophagy but not apoptosis.

Long Noncoding RNAs in Myocardial Ischemia-Reperfusion Injury

Following an acute myocardial infarction, reperfusion therapy is currently the most effective way to save the ischemic myocardium; however, restoring blood flow may lead to a myocardial ischemia-reperfusion injury (MIRI). Recent studies have confirmed that long-chain noncoding RNAs (LncRNAs) play important roles in the pathophysiology of MIRIs. These LncRNA-mediated roles include cardiomyocyte apoptosis, autophagy, necrosis, oxidative stress, inflammation, mitochondrial dysfunction, and calcium overload, which are regulated through the expression of target genes. Thus, LncRNAs may be used as clinical diagnostic markers and therapeutic targets to treat or prevent MIRI. This review evaluates the research on LncRNAs involved in MIRIs and provides new ideas for preventing and treating this type of injury.

MiRNA-26a inhibits myocardial infarction-induced apoptosis by targeting PTEN via JAK/STAT pathways

INTRODUCTION

Acute myocardial infarction (MI) is a common cause of the morbidity and mortality of cardiovascular diseases in the world. Acute MI lead to cardiovascular output after formation of myocardial ischemia and circulatory arrest in coronary heart diseases. However, the mechanisms underlying MI injury are poorly understood. We explored the part played by miR-26a in myocardial infarction (MI).

MATERIAL AND METHODS

Decreased miR-26a expression in H2O2-treated newborn murine ventricular cardiomyocytes (NMVCs) was observed, as well as in the infarcted heart of MI mouse model, compared to untreated NMVCs and healthy mouse heart tissue, respectively. Conversely, the upregulation of phosphatase and tensin homolog (PTEN) was observed in H2O2-treated NMVCs, and in infarcted hearts. An MTT assay and BrdU staining showed that H2O2 treatment attenuated cell viability in NMVCs, whereas miR-26a overexpression increased cell viability. Both TUNEL assay and flow cytometry (FC) displayed that miR-26a expression suppressed H2O2-induced cell apoptosis. Besides, miR-26a overexpression suppressed the upregulation of PTEN expression in H2O2-treated NMVCs by directly binding to PTEN 3'-UTR.

RESULTS

PI3K/Akt and JAK/STAT signal transduction pathways were found to be regulated through cross-talk between miR-26a and PTEN. Furthermore, agomiR-26a treatment in MI mouse model considerably suppressed the size of the infarcted regions, and improved cardiac activity.

CONCLUSIONS

MiR-26a expression in MI cardiac tissues was downregulated in response to H2O2 stress, whereas it could still protect against cell death by modulation of the PI3K/Akt and JAK/STAT signal transduction pathways by directly targeting PTEN.

MicroRNA-200a represses myocardial infarction-related cell death and inflammation by targeting the Keap1/Nrf2 and β-catenin pathways

BACKGROUND

Acute myocardial infarction (MI) is a main cause of emergency death in the world. MicroRNAs (miRs/miRNAs) are a series of small non-coding RNA molecules, which regulate cardiovascular disorders that involve MI. In this study, we explored the function of miR-200a in MI treatment.

METHODS

We observed down-regulation of miR-200a levels and up-regulation of Keap1 and β-catenin levels in H₂O₂-treated newborn murine ventricular cardiomyocytes (NMVCs) and the infarcted heart tissues of MI mouse models, compared to the non-treated NMVCs and normal heart tissues of healthy mice.

RESULTS

CCK-8 and colony formation assays indicated the reduction in NMVC vitality due to H₂O₂ treatment and the recovery of cell vitality due to miR-200a overexpression, respectively. Flow cytometry with Annexin and PI staining indicated the inhibition of H₂O₂-triggered cell apoptosis through ectopically expressed miR-200a. Western blotting and ELISA analyses that detected pro-inflammatory cell factors [interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α] confirmed that miR-200a prevented H₂O₂-induced NMVC inflammation. Moreover, miR-200a inhibited up-regulation of Keap1 and β-catenin expression in H₂O₂-treated NMVCs by directly binding with the 3'-UTR regions of both Keap1 and β-catenin. Furthermore, overexpression of Keap1 and β-cateninin in H₂O₂-treated NMVCs with recovered miR-200a elevated inflammation and apoptosis, respectively.

CONCLUSION

The results showed that miR-200a expression was inhibited in murine cardiomyocytes due to H₂O₂ stress in MI cardiac tissues and overexpressed miR-200a could protect the cells from death by regulating the Keap1/Nrf2 and β-catenin signal transduction pathways.

MiR-21 mediates the protection of kaempferol against hypoxia/reoxygenation-induced cardiomyocyte injury via promoting Notch1/PTEN/AKT signaling pathway

Kaempferol, a natural flavonoid compound, possesses potent myocardial protective property in ischemia/reperfusion (I/R), but the underlying mechanism is not well understood. The present study was aimed to explore whether miR-21 contributes to the cardioprotective effect of kaempferol on hypoxia/reoxygenation (H/R)-induced H9c2 cell injury via regulating Notch/phosphatase and tensin homologue (PTEN)/Akt signaling pathway. Results revealed that kaempferol obviously attenuates H/R-induced the damages of H9c2 cells as evidence by the up-regulation of cell viability, the down-regulation of lactate dehydrogenase (LDH) activity, the reduction of apoptosis rate and pro-apoptotic protein (Bax) expression, and the increases of anti-apoptotic protein (Bcl-2) expression. In addition, kaempferol enhanced miR-21 level in H9c2 cells exposed to H/R, and inhibition of miR-21 induced by transfection with miR-21 inhibitor significantly blocked the protection of kaempferol against H/R-induced H9c2 cell injury. Furthermore, kaempferol eliminated H/R-induced oxidative stress and inflammatory response as illustrated by the decreases in reactive oxygen species generation and malondialdehyde content, the increases in antioxidant enzyme superoxide dismutase and glutathione peroxidase activities, the decreases in pro-inflammatory cytokines interleukin (IL)-1β, IL-8 and tumor necrosis factor-alpha levels, and an increase in anti-inflammatory cytokine IL-10 level, while these effects of kaempferol were all reversed by miR-21 inhibitor. Moreover, results elicited that kaempferol remarkably blocks H/R-induced the down-regulation of Notch1 expression, the up-regulation of PTEN expression, and the reduction of P-Akt/Akt, indicating that kaempferol promotes Notch1/PTEN/AKT signaling pathway, and knockdown of Notch1/PTEN/AKT signaling pathway induced by Notch1 siRNA also abolished the protection of kaempferol against H/R-induced the damage of H9c2 cells. Notably, miR-21 inhibitor alleviated the promotion of kaempferol on Notch/PTEN/Akt signaling pathways in H9c2 cells exposed to H/R. Taken together, these above findings suggested thatmiR-21 mediates the protection of kaempferol against H/R-induced H9c2 cell injuryvia promoting Notch/PTEN/Akt signaling pathway.

LncRNA A2M-AS1 lessens the injury of cardiomyocytes caused by hypoxia and reoxygenation via regulating IL1R2

BACKGROUND

Myocardial ischemia and reperfusion injury (MI/RI) is a complex pathophysiological process, which can lead to severe myocardial injury. The long noncoding RNA alpha-2-macroglobulin antisense RNA 1 (A2M-AS1) has been revealed to be abnormally expressed in MI, However, its function in MI and the potential mechanism are still unclear.

OBJECTIVE

To evaluate the functional role of A2M-AS1 in hypoxia/reoxygenation (H/R)-induced neonatal cardiomyocytes and its potential molecular mechanism.

METHODS

Dataset GSE66360 was obtained from GEO database for analyzing the RNA expression of A2M-AS1 and interleukin 1 receptor type 2 (IL1R2). KEGG pathway enrichment analysis of the genes that co-expressed with A2M-AS1 was performed. Human neonatal cardiomyocytes were subjected to H/R to construct in vitro models. QRT-PCR and Western blot were adopted to test the levels of mRNA and protein. The viability and apoptosis of cardiomyocytes were tested by CCK-8 and flow cytometry assays, respectively.

RESULTS

The expression of A2M-AS1 was notably downregulated in H/R-treated cardiomyocytes. Overexpression of A2M-AS1 can notably enhance the cell viability of H/R-damaged cardiomyocytes, whereas knockdown of A2M-AS1 showed the opposite outcomes. Besides, a negative correlation was showed between A2M-AS1 and IL1R2 expression. In H/R-treated cardiomyocytes, overexpression of IL1R2 weakened the promoting proliferation and anti-apoptosis effects caused by overexpressing A2M-AS1, however, IL1R2-knockdown abolished the anti-proliferation and pro-apoptosis effects caused by silencing A2M-AS1.

CONCLUSION

This study demonstrates the potential regulatory role of A2M-AS1/ IL1R2 axis in cardiomyocytes suffered from H/R, and provides insight into the protection of MI/RI.

Differential expression of miR-142-3p protects cardiomyocytes from myocardial ischemia-reperfusion via TLR4/NFkB axis

Our research aims to explore the impact of miR-142 on myocardial apoptosis in the mouse ischemia and reperfusion (IR) model and investigate the underlying mechanisms at the molecular level. A considerable downregulation of miR-142 was observed in the cardiac area of mice post IR modeling. To understand the regulatory function of IR-induced miR-142 downregulation, the animals were categorized into four groups: IR model group; IR + agomir-142 group (IR mice treated with agomir-142); IR + antagomir-142 group (IR mice treated with antagomir-142); IR + agomir-142 + negative control (NC) group (IR mice processed with agomir-NC). The results indicated that agomir-142 upregulation was capable of shrinking IR damage-triggered infarction of the ventriculus sinister, strengthening myocardial function, and guarding against cardiomyocyte apoptosis, whereas further decreased miR-142 with antagomir-142 infection displayed negative influence of miR-142 against mice IR damage. In the cellular assay, miR-142 overexpression significantly improved proliferation and inhibited the apoptosis of neonatal rat cardiomyocytes (NRCs). Moreover, we found that miR-142 reduced the Bcl-2/Bax ratio and upregulated hydrogen peroxide (H₂ O₂ )-induced caspase-3 expression. Furthermore, transfection with an miR-142 mimic prevented the upregulation of TLR4/NFkB expression and activation in H₂ O₂ -treated NRCs. Our findings also revealed that miR-142 is linked to the 3'-untranslated area of the TLR4 gene. In addition, TLR4 overexpression considerably ablated the protective effects of miR-142 in terms of the cell viability of H₂ O₂ -treated NRCs. Taken together, miR-142 agomir injection in mice and miR-142 mimic transfection in NRCs plays a role in protecting the heart from IR damage and malfunction via the TLR4/NFkB axis both in vivo and in vitro.

Repurposing minocycline for COVID-19 management: mechanisms, opportunities, and challenges

INTRODUCTION

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has rapidly grown into a public health emergency that has placed the national health systems as well as scientific research communities under enormous pressures. Drug repurposing or repositioning is a well-known strategy that seeks to deploy existing licensed drugs for newer indications and provides the quickest possible transition from bench to clinics for unmet therapeutic needs. Given the current, urgent, and dire need for effective therapies against novel coronavirus-19, this approach is particularly appealing.

AREAS COVERED

Here, we review the significant anti-inflammatory, immunomodulatory, and antiviral properties of minocycline as potential mechanisms for efficacy against the novel coronavirus and highlight the promises and pitfalls of this approach.

EXPERT OPINION

As compared to other agents being investigated for COVID-19, minocycline offers distinct advantages in terms of potential efficacy in patients with life-threatening acute respiratory distress syndrome (ARDS) and myocardial injury, well-known safety and interaction profile, relatively low costs, and widespread availability. We call upon public and private funders to facilitate urgent and rigorous research efforts before evidence-based recommendations for its widespread use can be made.

Targeting Calcium Homeostasis in Myocardial Ischemia/Reperfusion Injury: An Overview of Regulatory Mechanisms and Therapeutic Reagents

Calcium homeostasis plays an essential role in maintaining excitation–contraction coupling (ECC) in cardiomyocytes, including calcium release, recapture, and storage. Disruption of calcium homeostasis may affect heart function, leading to the development of various heart diseases. Myocardial ischemia/reperfusion (MI/R) injury may occur after revascularization, which is a treatment used in coronary heart disease. MI/R injury is a complex pathological process, and the main cause of increased mortality and disability after treatment of coronary heart disease. However, current methods and drugs for treating MI/R injury are very scarce, not ideal, and have limitations. Studies have shown that MI/R injury can cause calcium overload that can further aggravate MI/R injury. Therefore, we reviewed the effects of critical calcium pathway regulators on MI/R injury and drew an intuitive diagram of the calcium homeostasis pathway. We also summarized and analyzed calcium pathway-related or MI/R drugs under research or marketing by searching Therapeutic Target and PubMed Databases. The data analysis showed that six drugs and corresponding targets are used to treat MI/R injury and involved in calcium signaling pathways. We emphasize the relevance of further detailed investigation of MI/R injury and calcium homeostasis and the therapeutic role of calcium homeostasis in MI/R injury, which bridges basic research and clinical applications of MI/R injury.

Dexmedetomidine pretreatment protects the heart against apoptosis in ischemia/reperfusion injury in diabetic rats by activating PI3K/Akt signaling in vivo and in vitro

Dexmedetomidine (DEX) exerts cardioprotection against ischemia/reperfusion injury. However, the precise mechanisms underlying this cardioprotective effect in diabetic rats are still not fully understood. The aim of the present study was to investigate the cardioprotective mechanism of DEX pretreatment on myocardial ischemia/reperfusion (I/R) injury in diabetic rats. A total of 25 streptozotocin-induced diabetic rats were equally randomized into five groups: i) Sham, ii) DEX (100 μg/kg); iii) myocardial I/R; iv) myocardial I/R+DEX (10 μg/kg); and v) myocardial I/R+DEX (100 μg/kg) groups. Primary cardiomyocytes were cultured in DEX for 1 h, and then oxygen and glucose deprivation (OGD)/R for 36 h. These results showed that pretreatment with DEX significantly decreased the I/R-induced size of the myocardial infarction, structural damage, morphological changes and apoptosis in myocardial cells, as well as levels of creatinine kinase, malondialdehyde and cardiac troponin I, and increased the I/R-induced superoxide dismutase activity in vivo and in vitro. Furthermore, immunohistochemical staining and western blot analysis revealed that DEX pretreatment significantly increased the I/R-induced expression levels of B-cell lymphoma 2 (Bcl-2), phosphorylated phosphoinositide 3-kinase (pPI3K) and pAkt, and significantly decreased those of pBcl-2 associated agonist of cell death, Bcl-2-associated X protein and cleaved caspase 3 in vivo and in vitro. In addition, all of these cardioprotective effects of DEX were reversed by yohimbine and LY294002 pretreatment. These results suggested that DEX pretreatment may activate the PI3K/Akt signaling pathway in an α₂ adrenoceptor-dependent manner. DEX pretreatment may exert cardioprotective effects against myocardial ischemia/reperfusion injury in diabetic rats through the I/R-induced inhibition of cell apoptosis by activating the PI3K/Akt signaling pathway.

miR-346 Inhibited Apoptosis Against Myocardial Ischemia-Reperfusion Injury via Targeting Bax in Rats

Purpose

Myocardial ischemia-reperfusion injury (MIRI) is a common pathophysiological process after occlusion of the blood vessels to restore blood supply. Apoptosis is one of the ways of myocardial cell death in this process. MicroRNAs (miRNAs), a class of short and noncoding RNAs, are involved in multiple biological processes by post-transcriptionally targeting their downstream effectors. To date, whether miRNAs exert biological effects in myocardial ischemia-reperfusion (I/R) injury remains to be further studied.

Methods

In this study, we induced MIRI model by ligating rat left anterior descending artery (LAD) for 30 mins and reperfusion for 2 hrs. The differential expression profile of miRNAs in rat models of MIRI was analyzed by miRNAs sequencing.

Results

We found that miRNAs sequencing analysis showed the expressions of 15 types of miRNAs, including miR-346, were downregulated and 29 types of miRNAs were elevated in the MIRI rat model. We observed the key regulator of apoptosis Bax was a predicted downstream target of miR-346 using online software TargetScan. And luciferase reporter assay was utilized to certify this prediction. Over-expression of miR-346 can attenuate myocardial injury and narrow infarct area by inhibiting myocardial cell apoptosis in rat models.

Conclusion

This study revealed a novel pathway, miR-346/Bax axis, in the regulation of apoptosis in MIRI and which might be a new molecular mechanism and therapeutic target.

The cystathionine γ-lyase/hydrogen sulfide pathway mediates the trimetazidine-induced protection of H9c2 cells against hypoxia/reoxygenation-induced apoptosis and oxidative stress

Objective:

Trimetazidine is a piperazine-derived metabolic agent. It exerts cardioprotective effects against myocardial ischemia/reperfusion (I/R) injury. In addition, studies confirm that the cystathionine γ-lyase (CSE)/hydrogen sulfide (H₂S) pathway serves a beneficent role in attenuating myocardial I/R injury. However, the underlying role of the CSE/H₂S pathway in the trimetazidine-induced protection against myocardial I/R injury remains elusive. Therefore, this study investigated whether trimetazidine ameliorates hypoxia/reoxygenation (H/R)-induced H9c2 cardiomyocyte injuries in an in vitro cell model of myocardial I/R injury, by enhancing the CSE/H₂S pathway.

Methods:

The H9c2 cell viability was determined with a cell counting Kit-8.

Results:

Trimetazidine significantly increased the cell viability and decreased lactate dehydrogenase (LDH) release in H/R-treated H9c2 cells. Additionally, trimetazidine increased the H₂S levels and the CSE mRNA and protein levels, promoting the CSE/H₂S pathway under H/R conditions. The inhibition of the CSE/H₂S pathway, induced by transfection with specific siRNA against human CSE (si-CSE), eliminated the trimetazidine-induced upregulation of cell viability, downregulation of LDH release, increase of caspase-3 activity and apoptosis regulator BAX expression, and the decrease of apoptosis regulator Bcl-2 expression, which suggests involvement of the CSE/H₂S pathway in trimetazidine-induced cardioprotection. Furthermore, trimetazidine mitigated the H/R-induced increase in reactive oxygen species production and NADPH oxidase 2 expression, and decrease in superoxide dismutase activity and glutathione level, in H9c2 cells. These effects were also reversed by si-CSE.

Conclusion:

This study revealed that the CSE/H₂S pathway mediates the trimetazidine-induced protection of H9c2 cardiomyocytes against H/R-induced damage by inhibiting apoptosis and oxidative stress.

Effects of tetracycline on myocardial infarct size in obese rats with chemically-induced colitis

Background

Recent evidence suggests that antibiotic-induced changes in the composition of intestinal microflora, as well as the systemic immunoendocrine effects that result from them, can modulate myocardial tolerance to ischemia-reperfusion injury. The aim of this study was to investigate the effects of tetracycline (TTC) on myocardial infarct size in the isolated hearts obtained from obese rats with chemically-induced colitis (CIC). The association between TTC-induced changes in infarct size and intestinal microbiome composition as well as plasma levels of cytokines and short-chain fatty acids (SCFAs) was also studied.

Methods

Obesity was induced in Wistar rats by feeding them a high-fat, high-carbohydrate diet for five weeks. A single rectal administration of 3% acetic acid (2 mL) to the rats resulted in CIC. Healthy rats as well as obese rats with CIC received TTC (15 mg daily for 3 days) via gavage. The rats were euthanized, after which isolated heart perfusion with simulated global ischemia and reperfusion was performed. Infarct size was determined histochemically. Lipopolysaccharide (LPS) and cytokine levels in plasma were measured by enzyme-linked immunosorbent assay, whereas SCFA levels in plasma were measured by gas chromatography/mass spectrometry. The intestinal microbiome was analyzed using reverse transcription polymerase chain reaction.

Results

The treatment with TTC resulted in significant infarct size limitation (50 ± 7 vs. 62 ± 4% for the control mice, p < 0.05) in the hearts from intact animals. However, infarct size was not different between the control rats and the obese rats with CIC. Furthermore, infarct size was significantly larger in TTC-treated obese rats with CIC than it was in the control animals (77 ± 5%, p < 0.05). The concentrations of proinflammatory cytokines and LPS in serum were elevated in the obese rats with CIC. Compared to the control rats, the rats with both obesity and CIC had lower counts of Lactobacillus and Bifidobacterium spp. but higher counts of Escherichia coli. The effects of TTC on infarct size were not associated with specific changes in SCFA levels.

Conclusions

TTC reduced infarct size in the healthy rats. However, this effect was reversed in the obese animals with CIC. Additionally, it was associated with specific changes in gut microbiota and significantly elevated levels of cytokines and LPS.

Tongxinluo Ameliorates Myocardial Ischemia-Reperfusion Injury Mainly via Activating Parkin-Mediated Mitophagy and Downregulating Ubiquitin-Proteasome System

OBJECTIVE

To investigate the protective effects and mechanism of Chinese herbal compound Tongxinluo Capsule (, TXL) on the Parkin-mediated mitophagy and the ubiquitin-proteasome system in a rat model of myocardial ischemia-reperfusion injury (MIRI).

METHODS

Seventy adult male Sprague-Dawley rats were randomly divided into 7 groups: sham group, MIRI group, low- and high-dose TXL (0.5 and 1 g·kg^-1·d^-1, respectively) groups, atorvastatin (ATV) group (7.2 g·kg^-1·d^-1), chloroquine (CQ) group (10 g·kg^-1·d^-1), and highdose TXL + CQ group. After pharmacological administration for 7 days, rats underwent left anterior descending artery ligation surgery to establish the MIRI models with 50 min ischemia followed by 4 h reperfusion. Blood was taken for cardiac troponin I (cTnI) detection and hearts were harvested for infarct staining and apoptosis detection. The autophagy or mitophagy proteins and ubiquitinated proteins were detected by Western blotting.

RESULTS

Compared with the sham group, the MIRI group exhibited a larger infarcted area (27.13%±0.01%, P<0.01), a higher apoptotic index (34.33%±2.03% vs.1.81%±0.03%, P<0.01), and higher cTnI expression (14.18±1.01 vs. 7.96±0.32, P<0.01). The mitochondrial integrity was damaged in the MIRI group, while TXL and ATV alleviated the damage of MIRI. More autophagosomes were observed in the high-dose TXL group than in the MIRI group (7.00±0.58 vs. 4.33±1.15, P<0.05). More amounts of PTEN-induced putative kinase protein 1 (PINK1) and Parkin translocated onto the mitochondria were detected in the high-dose TXL group than in the MIRI group (P<0.05). The ubiquitin response was signifificantly downregulated in the high-dose TXL group relative to the MIRI group (P<0.05). CQ administration abolished the activation of autophagy flux and the PINK1/ Parkin pathway induced by high-dose of TXL.

CONCLUSIONS

TXL ameliorates MIRI via activating Parkin-mediated mitophagy in rats. The downregulation of the ubiquitin-proteasome system is also involved.

MicroRNA‑21 contributes to the puerarin‑induced cardioprotection via suppression of apoptosis and oxidative stress in a cell model of ischemia/reperfusion injury

Puerarin, a major bioactive constituent of the Radix puerariae, can ameliorate myocardial ischemia/reperfusion (I/R) injury. Emerging evidence supports that microRNA (miR)‑21 functions as a protective factor against I/R and/or hypoxia‑reperfusion (H/R)‑induced myocardial injury. However, the role of miR‑21 in the cardioprotective effect of puerarin remains unclear. Therefore, the purpose of the present study was to demonstrate the involvement of miR‑21 in the cardioprotective mechanisms of puerarin using a cell model of I/R injury, generated by culturing rat H9c2 cardiomyocytes under H/R conditions. The results demonstrated that pre‑treatment with puerarin significantly increased cell viability, decreased lactate dehydrogenase activity and upregulated miR‑21 expression in H/R‑treated H9c2 cells. Transfection of an miR‑21 inhibitor led to an increase in H/R‑induced cytotoxicity and reversed the protective effects of puerarin. Additionally, miR‑21 inhibition attenuated the puerarin‑induced decrease in the rate of apoptosis, caspase‑3 activity and the expression of apoptosis regulator Bax, and increased apoptosis regulator Bcl‑2 expression, under H/R conditions. Furthermore, puerarin mitigated H/R‑induced oxidative stress as evidenced by the decrease in endogenous reactive oxygen species production, malondialdehyde content and NADPH oxidase 2 expression, and enhanced the antioxidative defense system as illustrated by the increase in superoxide dismutase activity, catalase and glutathione peroxidase levels. These effects were all eliminated by miR‑21 inhibitor transfection. Furthermore, the miR‑21 inhibitor exacerbated the H/R‑induced oxidative stress and attenuated the antioxidative defense system in H/R‑treated H9c2 cells. Taken together, the results suggested that miR‑21 mediated the cardioprotective effects of puerarin against myocardial H/R injury by inhibiting apoptosis and oxidative stress.

NEAT1 promotes myocardial ischemia-reperfusion injury via activating the MAPK signaling pathway

Myocardial ischemia-reperfusion (IR) injury is a common cardiovascular problem, which remains a major cause of death in the world. Emerging evidence has suggested that long noncoding RNAs are crucial players in myocardial injury. However, the functional involvement of nuclear enriched abundant transcript 1 (NEAT1) in myocardial IR injury remains poorly investigated. Our study focused on the mechanism of NEAT1 in myocardial IR injury. Here, we reported a crucial role for NEAT1 in exacerbating cardiac IR injury. NEAT1 was greatly increased in myocardial IR injury mice models. As exhibited knockdown of NEAT1 resulted in attenuated myocardial IR injury in vivo. In addition, we found that NEAT1 was dramatically induced by hypoxia/reoxygenation in H9c2 cells. Lactate dehydrogenase (LDH), malondialdehyde, reactive oxygen species levels, and endoplasmic reticulum stress-regulated cardiomyocyte apoptosis were inhibited by the downregulation of NEAT1. Here, it was shown that knockdown of NEAT1 was able to repress tumor necrosis factor-α, interleukin-1β, and IL-6 expression. The silence of NEAT1 protected against IR injury via decreasing troponin levels, cardiocytes apoptosis, creatine kinase, and lactate LDH release in vivo. Meanwhile, the mitogen-activated protein kinase (MAPK) signaling was involved in NEAT1-mediated myocardial IR injury. In summary, our data indicated that NEAT1 contributed to myocardial IR injury via activating the MAPK pathway.

Stomatin-like protein-2 relieve myocardial ischemia/reperfusion injury by adenosine 5'-monophosphate-activated protein kinase signal pathway

Previous studies have shown that stomatin-like protein-2 (SLP-2) could regulate mitochondrial biogenesis and function. The study was designed to explore the contribution of SLP-2 to the myocardial ischemia and reperfusion (I/R) injury. Anesthetized rats were treated with SLP-2 and subjected to ischemia for 30 minutes before 3 hours of reperfusion. An oxygen-glucose deprivation/reoxygenation model of I/R was established in H9C2 cells. In vivo, SLP-2 significantly improved cardiac function recovery of myocardial I/R injury rats by increasing fractional shortening and ejection fraction. SLP-2 pretreatment alleviated infarct area and myocardial apoptosis, which was paralleled by decreasing the level of cleaved caspase-3 and the ratio of Bax/Bcl-2, increasing the content of superoxide dismutase and reducing oxidative stress damage in serum. In addition, SLP-2 increased the level of ATP and stabilized mitochondrial potential (Ψm). The present in vitro study revealed that overexpression with SLP-2 reduced H9C2 cells apoptosis, accompanied by an increased level of ATP, the ratio of mitochondrial DNA/nuclear DNA, activities of complex II and V, and decreased the production of mitochondrial reactive oxygen species. Simultaneously, SLP-2 activated the adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling pathway in myocardial I/R injury rats and H9C2 cells. This study revealed that SLP-2 mediates the cardioprotective effect against I/R injury by regulating AMPK signaling pathway.

Cardioprotection of Ginkgolide B on Myocardial Ischemia/Reperfusion-Induced Inflammatory Injury via Regulation of A20-NF-κB Pathway

Inflammation urges most of the characteristics of plaques involved in the pathogenesis of myocardial ischemia/reperfusion injury (MI/RI). In addition, inflammatory signaling pathways not only mediate the properties of plaques that precipitate ischemia/reperfusion (I/R) but also influence the clinical consequences of the post-infarction remodeling and heart failure. Here, we studied whether Ginkgolide B (GB), an effective anti-inflammatory monomer, improved MI/RI via suppression of inflammation. Left anterior descending (LAD) coronary artery induced ischemia/reperfusion (I/R) of rats or A20 silencing mice, as well as hypoxia/reoxygenation (H/R) induced damages of primary cultured rat neonatal ventricular myocytes or A20 silencing ventricular myocytes, respectively, served as MI/RI model in vivo and in vitro to discuss the anti-I/R injury properties of GB. We found that GB significantly alleviated the symptoms of MI/RI evidently by reducing infarct size, preventing ultrastructural changes of myocardium, depressing Polymorphonuclears (PMNs) infiltration, lessening histopathological damage and suppressing the excessive inflammation. Further study demonstrated that GB remarkably inhibited NF-κB p65 subunit translocation, IκB-α phosphorylation, IKK-β activity, as well as the downstream inflammatory cytokines and proteins expressions via zinc finger protein A20. In conclusion, GB could alleviate MI/RI-induced inflammatory response through A20-NF-κB signal pathway, which may give us new insights into the preventive strategies for MI/RI disease.

Why is Skeletal Muscle Regeneration Impaired after Myonecrosis Induced by Viperid Snake Venoms?

Skeletal muscle regeneration after myonecrosis involves the activation, proliferation and fusion of myogenic cells, and a coordinated inflammatory response encompassing phagocytosis of necrotic cell debris, and the concerted synthesis of cytokines and growth factors. Myonecrosis often occurs in snakebite envenomings. In the case of venoms that cause myotoxicity without affecting the vasculature, such as those of many elapid snakes, regeneration proceeds successfully. In contrast, in envenomings by most viperid snakes, which affect the vasculature and extracellular matrix in addition to muscle fibers, regeneration is largely impaired and, therefore, the muscle mass is reduced and replaced by fibro-adipose tissue. This review discusses possible causes for such poor regenerative outcome including: (a) damage to muscle microvasculature, which causes tissue hypoxia and affects the inflammatory response and the timely removal of necrotic tissue; (b) damage to intramuscular nerves, which results in atrophy of regenerating fibers; (c) degradation of muscle cell basement membrane, compromising the spatial niche for proliferating myoblasts; (d) widespread degradation of the extracellular matrix; and (e) persistence of venom components in the damaged tissue, which may affect myogenic cells at critical points in the regenerative process. Understanding the causes of poor muscle regeneration may pave the way for the development of novel therapeutic interventions aimed at fostering the regenerative process in envenomed patients.

Long non-coding RNA-ROR aggravates myocardial ischemia/reperfusion injury

Long non-coding RNAs (lncRNAs) play an important role in the pathogenesis of cardiovascular diseases, especially in myocardial infarction and ischemia/reperfusion (I/R). However, the underlying molecular mechanism remains unclear. In this study, we determined the role and the possible underlying molecular mechanism of lncRNA-ROR in myocardial I/R injury. H9c2 cells and human cardiomyocytes (HCM) were subjected to either hypoxia/reoxygenation (H/R), I/R or normal conditions (normoxia). The expression levels of lncRNA-ROR were detected in serum of myocardial I/R injury patients, H9c2 cells, and HCM by qRT-PCR. Then, levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX) were measured by kits. Cell viability, apoptosis, apoptosis-associated factors, and p38/MAPK pathway were examined by MTT, flow cytometry, and western blot assays. Furthermore, reactive oxygen species (ROS) production was determined by H2DCF-DA and MitoSOX Red probes with flow cytometry. NADPH oxidase activity and NOX2 protein levels were measured by lucigenin chemiluminescence and western blot. Results showed that lncRNA-ROR expression was increased in I/R patients and in H/R treatment of H9c2 cells and HCM. Moreover, lncRNA-ROR significantly promoted H/R-induced myocardial injury via stimulating release of LDH, MDA, SOD, and GSH-PX. Furthermore, lncRNA-ROR decreased cell viability, increased apoptosis, and regulated expression of apoptosis-associated factors. Additionally, lncRNA-ROR increased phosphorylation of p38 and ERK1/2 expression and inhibition of p38/MAPK, and rescued lncRNA-ROR-induced cell injury in H9c2 cells and HCM. ROS production, NADPH oxidase activity, and NOX2 protein levels were promoted by lncRNA-ROR. These data suggested that lncRNA-ROR acted as a therapeutic agent for the treatment of myocardial I/R injury.

MicroRNA-93 inhibits ischemia-reperfusion induced cardiomyocyte apoptosis by targeting PTEN

MicroRNAs have been implicated in some biological and pathological processes, including the myocardial ischemia/reperfusion (I/R) injury. Recent findings demonstrated that miR-93 might provide a potential cardioprotective effect on ischemic heart disease. This study was to investigate the role of miR-93 in I/R-induced cardiomyocyte injury and the potential mechanism. In this study, we found that hypoxia/reoxygenation (H/R) dramatically increased LDH release, MDA contents, ROS generation, and endoplasmic reticulum stress (ERS)-mediated cardiomyocyte apoptosis, which were attenuated by co-transfection with miR-93 mimic. Phosphatase and tensin homolog (PTEN) was identified as the target gene of miR-93. Furthermore, miR-93 mimic significantly increased p-Akt levels under H/R, which was partially released by LY294002. In addtion, Ad-miR-93 also attenuated myocardial I/R injury in vivo, manifested by reduced LDH and CK levels, infarct area and cell apoptosis. Taken together, our findings indicates that miR-93 could protect against I/R-induced cardiomyocyte apoptosis by inhibiting PI3K/AKT/PTEN signaling.

MicroRNA-206 Protects against Myocardial Ischaemia-Reperfusion Injury in Rats by Targeting Gadd45β

MicroRNAs are widely involved in the pathogenesis of cardiovascular diseases through regulating gene expression via translational inhibition or degradation of their target mRNAs. Recent studies have indicated a critical role of microRNA-206 in myocardial ischaemia-reperfusion (I/R) injury. However, the function of miR-206 in myocardial I/R injury is currently unclear. The present study was aimed to identify the specific role of miR-206 in myocardial I/R injury and explore the underlying molecular mechanism. Our results revealed that the expression level of miR-206 was significantly decreased both in rat I/R group and H9c2 cells subjected to hypoxia/reoxygenation (H/R) compared with the corresponding control. Overexpression of miR-206 observably decreased infarct size and inhibited the cardiomyocyte apoptosis induced by I/R injury. Furthermore, bioinformatics analysis, luciferase activity and western blot assay proved that Gadd45β (growth arrest DNA damage-inducible gene 45β) was a direct target gene of miR-206. In addition, the expression of pro-apoptotic-related genes, such as p53, Bax and cleaved caspase3, was decreased in association with the down-regulation of Gadd45β. In summary, this study demonstrates that miR-206 could protect against myocardial I/R injury by targeting Gadd45β.

Icariin protects against ischemia‑reperfusion injury in H9C2 cells by upregulating heat shock protein 20

Icariin (ICA) has been implicated in certain biological and pathological processes, including myocardial ischemia/reperfusion (I/R) injury. The aim of the present study was to investigate the role of ICA in I/R‑induced cardiomyocyte injury and the potential underlying mechanism. Cell proliferation and apoptosis of H9C2 cells was determined by cell counting kit‑8 and flow cytometry assays. In addition, reactive oxygen species (ROS) production in H9C2 cells was measured by flow cytometry. Reverse transcription‑quantitative polymerase chain reaction and western blot assay were performed to examine the expression levels of proteins, including HSP20, B‑cell lymphoma 2 (Bcl‑2), cytochrome complex (Cyt‑c), apoptotic protease activating factor 1 (APAF1), caspase‑9 andcaspase‑3, and the phosphorylation of Akt (p‑Akt) in H9C2 cells. The present results demonstrated that, compared with the control group, the I/R group demonstrated significantly reduced levels of HSP20 expression and cell proliferation, and increased apoptosis and ROS production in H9C2 cells. In parallel, the expression levels of Cyt‑c, APAF1, caspase‑9 and caspase‑3 were significantly increased in the I/R group, although Bcl‑2 and p‑Akt/Akt expression levels were decreased. Furthermore, compared with the I/R group, ICA treatment and/or HSP20 overexpression significantly improved cardiac function, as evidenced by promoted cell proliferation and inhibited apoptosis of H9C2 cells. The current study indicates that ICA exerts a cardioprotective effect against I/R injury, which is associated with the upregulation of HSP20.

The mitochondrial permeability transition pore in AD 2016: An update

Over the past 30years the mitochondrial permeability transition - the permeabilization of the inner mitochondrial membrane due to the opening of a wide pore - has progressed from being considered a curious artifact induced in isolated mitochondria by Ca(2+) and phosphate to a key cell-death-inducing process in several major pathologies. Its relevance is by now universally acknowledged and a pharmacology targeting the phenomenon is being developed. The molecular nature of the pore remains to this day uncertain, but progress has recently been made with the identification of the FOF1 ATP synthase as the probable proteic substrate. Researchers sharing this conviction are however divided into two camps: these believing that only the ATP synthase dimers or oligomers can form the pore, presumably in the contact region between monomers, and those who consider that the ring-forming c subunits in the FO sector actually constitute the walls of the pore. The latest development is the emergence of a new candidate: Spastic Paraplegia 7 (SPG7), a mitochondrial AAA-type membrane protease which forms a 6-stave barrel. This review summarizes recent developments of research on the pathophysiological relevance and on the molecular nature of the mitochondrial permeability transition pore. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.

Illuminating drug action by network integration of disease genes: a case study of myocardial infarction

Drug discovery has produced many successful therapeutic agents; however, most of these drugs were developed without a deep understanding of the system-wide mechanisms of action responsible for their indications. Gene-disease associations produced by molecular and genetic studies of complex diseases provide great opportunities for a system-level understanding of drug activity. In this study, we focused on acute myocardial infarction (MI) and conducted an integrative network analysis to illuminate drug actions. We integrated MI drugs, MI drug interactors, drug targets, and MI disease genes into the human interactome and showed that MI drug targets are significantly proximate to MI disease proteins. We then constructed a bipartite network of MI-related drug targets and MI disease proteins and derived 12 drug-target-disease (DTD) modules. We assessed the biological relevance of these modules and demonstrated the benefits of incorporating disease genes. The results indicate that DTD modules provide insights into the mechanisms of action of MI drugs and the cardiovascular (side) effects of non-MI drugs.