Myocardial Ischemia-reperfusion Injury Research Articles

Uncoupling Protein 2 Alleviates Myocardial Ischemia/Reperfusion Injury by Inhibiting Cardiomyocyte Ferroptosis

Introduction: Following our recent finding that Ucp2 knockout promotes ferroptosis, we aimed to examine whether UCP2 alleviates myocardial ischemia/reperfusion injury (MI/RI) by inhibiting ferroptosis. Methods: The left anterior descending coronary arteries of wild-type and Ucp2−/− C57BL/6 mice were ligated for 30 min and reperfused for 2 h to establish an MI/RI model. The effects of UCP2 on ferroptosis and MI/RI were determined by echocardiography, 2,3,5-triphenylttrazolium chloride staining, hematoxylin-eosin staining, Masson’s trichrome staining, Sirius red staining, and analysis of myocardial injury markers and ferroptosis indicators. Ferrostatin-1 (Fer-1) and erastin (Era) were used to investigate whether UCP2 alleviated MI/RI by inhibiting ferroptosis and the molecular mechanism. Results: UCP2 was upregulated in the MI/RI model in WT mice. Deletion of Ucp2 exacerbated ferroptosis, altered the expression levels of multiple ferroptosis-related genes, and significantly exacerbated MI/RI. Knockout of Ucp2 promoted ferroptosis induced by Era and inhibited the antiferroptotic effects of Fer-1. Knockout of Ucp2 activated the p53/TfR1 pathway to exacerbate ferroptosis. Conclusion: Our results showed that UCP2 inhibited ferroptosis in MI/RI, which might be related to regulation of the p53/TfR1 pathway.

Investigating the Therapeutic Effects of Ferroptosis on Myocardial Ischemia‐Reperfusion Injury Using a Dual‐Locking Mitochondrial Targeting Strategy

AbstractResearch on ferroptosis in myocardial ischemia/reperfusion injury (MIRI) using mitochondrial viscosity as a nexus holds great promise for MIRI therapy. However, high‐precision visualisation of mitochondrial viscosity remains a formidable task owing to the debilitating electrostatic interactions caused by damaged mitochondrial membrane potential. Herein, we propose a dual‐locking mitochondria‐targeting strategy that incorporates electrostatic forces and probe‐protein molecular docking. Even in damaged mitochondria, stable and precise visualisation of mitochondrial viscosity in triggered and medicated MIRI was achieved owing to the sustained driving forces (e.g., pi‐cation, pi‐alkyl interactions, etc.) between the developed probe, CBS, and the mitochondrial membrane protein. Moreover, complemented by a western blot, we confirmed that ferrostatin‐1 exerts its therapeutic effect on MIRI by improving the system xc−/GSH/GPX4 antioxidant system, confirming the therapeutic value of ferroptosis in MIRI. This study presents a novel strategy for developing robust mitochondrial probes, thereby advancing MIRI treatment.

Investigating the Therapeutic Effects of Ferroptosis on Myocardial Ischemia-Reperfusion Injury Using a Dual-Locking Mitochondrial Targeting Strategy.

Research on ferroptosis in myocardial ischemia/reperfusion injury (MIRI) using mitochondrial viscosity as a nexus holds great promise for MIRI therapy. However, high-precision visualisation of mitochondrial viscosity remains a formidable task owing to the debilitating electrostatic interactions caused by damaged mitochondrial membrane potential. Herein, we propose a dual-locking mitochondria-targeting strategy that incorporates electrostatic forces and probe-protein molecular docking. Even in damaged mitochondria, stable and precise visualisation of mitochondrial viscosity in triggered and medicated MIRI was achieved owing to the sustained driving forces (e.g., pi-cation, pi-alkyl interactions, etc.) between the developed probe, CBS, and the mitochondrial membrane protein. Moreover, complemented by a western blot, we confirmed that ferrostatin-1 exerts its therapeutic effect on MIRI by improving the system xc-/GSH/GPX4 antioxidant system, confirming the therapeutic value of ferroptosis in MIRI. This study presents a novel strategy for developing robust mitochondrial probes, thereby advancing MIRI treatment.

Autosis: a new form of cell death in myocardial ischemia-reperfusion injury.

Cardiomyocytes undergo a variety of cell death events during myocardial ischemia‒reperfusion injury (MIRI). Understanding the causes of cardiomyocyte mortality is critical for the prevention and treatment of MIRI. Among the various types of cell death, autosis is a recently identified type of autophagic cell death with distinct morphological and chemical characteristics. Autosis can be attenuated by autophagy inhibitors but not reversed by apoptosis or necrosis inhibitors. In recent years, it has been shown that during the late phase of reperfusion, autosis is activated, which exacerbates myocardial injury. This article describes the characteristics of autosis, autophagic cell death, and the relationship between autophagic cell death and autosis; reviews the mechanism of autosis in MIRI; and discusses its clinical significance.

Inhibition of circ_0073932 attenuates myocardial ischemia‒reperfusion injury via miR-493-3p/FAF1/JNK.

Oxidative stress and apoptosis play crucial roles in myocardial ischemia‒reperfusion injury (MIRI). In this study, we investigated the role of circ_0073932 in MIRI as well as its molecular mechanism. A hypoxia/reoxygenation (H/R) cardiomyocyte model was established with H9C2 cardiomyocytes, and RT-qPCR was used to measure gene expression. We observed that circ_0073932 expression was abnormally increased in the H/R cardiomyocyte model and in blood samples from MIRI patients. Inhibition of circ_0073932 suppressed H/R-induced cell apoptosis, oxidative stress (ROS, LDH and MDA), and p-JNK expression. Dual luciferase reporter assays showed that circ_0073932 targeted the downregulation of miR-493-3p, and miR-493-3p targeted the downregulation of FAF1. Furthermore, si-circ_0073932, an miR-493-3p inhibitor, oe-FAF1, or si-FAF1 were transfected into H9C2 cardiomyocytes to investigate the roles of these factors in MIRI. Our results showed that compared with the H/R group, si-circ_0073932 inhibited H/R-induced cell apoptosis, oxidative stress (ROS, LDH and MDA), and p-JNK expression. These results were reversed by the miR-493-3p inhibitor or oe-FAF1. Finally, a rat model of MIRI was established, and si-circ_0073932 was administered. Inhibition of circ_0073932 reduced the area of myocardial infarction and decreased the levels of apoptosis and oxidative stress by inhibiting the JNK signaling pathway. Our study indicated that circ_0073932 mediates MIRI via miR-493-3p/FAF1/JNK in vivo and in vitro, revealing novel insights into the pathogenesis of MIRI and providing a new target for the clinical treatment of MIRI.

Oral-gut microbial transmission promotes diabetic coronary heart disease

BackgroundDiabetes is a predominant driver of coronary artery disease worldwide. This study aims to unravel the distinct characteristics of oral and gut microbiota in diabetic coronary heart disease (DCHD). Simultaneously, we aim to establish a causal link between the diabetes-driven oral-gut microbiota axis and increased susceptibility to diabetic myocardial ischemia–reperfusion injury (MIRI).MethodsWe comprehensively investigated the microbial landscape in the oral and gut microbiota in DCHD using a discovery cohort (n = 183) and a validation chohort (n = 68). Systematically obtained oral (tongue-coating) and fecal specimens were subjected to metagenomic sequencing and qPCR analysis, respectively, to holistically characterize the microbial consortia. Next, we induced diabetic MIRI by administering streptozotocin to C57BL/6 mice and subsequently investigated the potential mechanisms of the oral-gut microbiota axis through antibiotic pre-treatment followed by gavage with specific bacterial strains (Fusobacterium nucleatum or fecal microbiota from DCHD patients) to C57BL/6 mice.ResultsSpecific microbial signatures such as oral Fusobacterium nucleatum and gut Lactobacillus, Eubacterium, and Roseburia faecis, were identified as potential microbial biomarkers in DCHD. We further validated that oral Fusobacterium nucleatum and gut Lactobacillus are increased in DCHD patients, with a positive correlation between the two. Experimental evidence revealed that in hyperglycemic mice, augmented Fusobacterium nucleatum levels in the oral cavity were accompanied by an imbalance in the oral-gut axis, characterized by an increased coexistence of Fusobacterium nucleatum and Lactobacillus, along with elevated cardiac miRNA-21 and a greater extent of myocardial damage indicated by TTC, HE, TUNEL staining, all of which contributed to exacerbated MIRI.ConclusionOur findings not only uncover dysregulation of the oral-gut microbiota axis in diabetes patients but also highlight the pivotal intermediary role of the increased abundance of oral F. nucleatum and gut Lactobacillus in exacerbating MIRI. Targeting the oral-gut microbiota axis emerges as a potent strategy for preventing and treating DCHD. Oral-gut microbial transmission constitutes an intermediate mechanism by which diabetes influences myocardial injury, offering new insights into preventing acute events in diabetic patients with coronary heart disease.Graphic

Myocardial Ischemia-Reperfusion Injury: Unraveling Pathophysiology, Clinical Manifestations, and Emerging Prevention Strategies.

Myocardial ischemia-reperfusion injury (MIRI) remains a challenge in the context of reperfusion procedures for myocardial infarction (MI). While early revascularization stands as the gold standard for mitigating myocardial injury, recent insights have illuminated the paradoxical role of reperfusion, giving rise to the phenomenon known as ischemia-reperfusion injury. This comprehensive review delves into the intricate pathophysiological pathways involved in MIRI, placing a particular focus on the pivotal role of endothelium. Beyond elucidating the molecular intricacies, we explore the diverse clinical manifestations associated with MIRI, underscoring its potential to contribute substantially to the final infarct size, up to 50%. We further navigate through current preventive approaches and highlight promising emerging strategies designed to counteract the devastating effects of the phenomenon. By synthesizing current knowledge and offering a perspective on evolving preventive interventions, this review serves as a valuable resource for clinicians and researchers engaged in the dynamic field of MIRI.

Epigallocatechin-3-gallate confers protection against myocardial ischemia/reperfusion injury by inhibiting ferroptosis, apoptosis, and autophagy via modulation of 14–3-3η

Previous studies have demonstrated that the underlying mechanisms of myocardial ischemia/reperfusion injury (MIRI) are complex and involve multiple types of regulatory cell death, including ferroptosis, apoptosis, and autophagy. Thus, we aimed to identify the mechanisms underlying MIRI and validate the protective role of epigallocatechin-3-gallate (EGCG) and its related mechanisms in MIRI. An in vivo and in vitro models of MIRI were constructed. The results showed that pretreatment with EGCG could attenuate MIRI, as indicated by increased cell viability, reduced lactate dehydrogenase (LDH) activity and apoptosis, inhibited iron overload, abnormal lipid metabolism, preserved mitochondrial function, decreased infarct size, maintained cardiac function, decreased reactive oxygen species (ROS) level, and reduced TUNEL-positive cells. Additionally, EGCG pretreatment could attenuate ferroptosis, apoptosis, and autophagy induced by MIRI via upregulating 14–3–3η protein levels. Furthermore, the protective effects of EGCG could be abolished with pAd/14–3–3η-shRNA or Compound C11 (a 14–3–3η inhibitor) but not pAd/NC-shRNA. In conclusion, EGCG pretreatment attenuated ferroptosis, apoptosis, and autophagy by mediating 14–3–3η and protected cardiomyocytes against MIRI.

Mild Therapeutic Hypothermia Alleviated Myocardial Ischemia/Reperfusion Injury via Targeting SLC25A10 to Suppress Mitochondrial Apoptosis

Myocardial ischemia/reperfusion injury (MI/RI) is identified as a severe vascular emergency, and the treatment strategy of MI/RI still needs further improvement. The present study aimed to investigate the potential effects of mild therapeutic hypothermia (MTH) on MI/RI and underlying mechanisms. In ischemia/reperfusion (I/R) rats, MTH treatment significantly improved myocardial injury, attenuated myocardial infarction, and inhibited the mitochondrial apoptosis pathway. The results of proteomics identified SLC25A10 as the main target of MTH treatment. Consistently, SLC25A10 expressions in I/R rat myocardium and hypoxia and reoxygenation (H/R) cardiomyocytes were significantly suppressed, which was effectively reversed by MTH treatment. In H/R cardiomyocytes, MTH treatment significantly improved cell injury, mitochondrial dysfunction, and inhibited the mitochondrial apoptosis pathway, which were partially reversed by SLC25A10 deletion. These findings suggested that MTH treatment could protect against MI/RI by modulating SLC25A10 expression to suppress mitochondrial apoptosis pathway, providing new theoretical basis for clinical application of MTH treatment for MI/RI.Graphical

Berberine inhibits excessive autophagy and protects myocardium against ischemia/reperfusion injury via the RhoE/AMPK pathway.

Several studies have shown that berberine (BBR) is effective in protecting against myocardial ischemia‑reperfusion injury (MI/RI). However, the precise molecular mechanism remains elusive. The present study observed the mechanism and the safeguarding effect of BBR against hypoxia/reoxygenation (H/R) myocardial injury in H9c2 cells. BBR pretreatment significantly improved the decrease of cell viability, P62 protein, Rho Family GTPase 3 (RhoE) protein, ubiquinone subunit B8 protein, ubiquinol‑cytochrome c reductase core protein U, the Bcl‑2‑associated X protein/B‑cell lymphoma 2 ratio, glutathione (GSH) and the GSH/glutathione disulphide (GSSG) ratio induced by H/R, while reducing the increase in lactate dehydrogenase, microtubule‑associated protein 1 light 3 protein, caspase‑3 activity, reactive oxygen species, GSSG and malonaldehyde caused by H/R. Transmission electron microscopy and LysoTracker Red DND‑99 staining results showed that BBR pretreatment inhibited H/R‑induced excessive autophagy by mediating RhoE. BBR also inhibited mitochondrial permeability transition, maintained the stability of the mitochondrial membrane potential, reduced the apoptotic rate, and increased the level of caspase‑3. However, the protective effects of BBR were attenuated by pAD/RhoE‑small hairpin RNA, rapamycin (an autophagy activator) and compound C (an AMP‑activated protein kinase inhibitor). These new findings suggested that BBR protects the myocardium from MI/RI by inhibiting excessive autophagy, maintaining mitochondrial function, improving the energy supply and redox homeostasis, and attenuating apoptosis through the RhoE/AMP‑activated protein kinase pathway.

Effect of lazaroid U-74389G and Sildenafil, alone or in combination, on pulmonary function during ischamia-reperfusion injury of myocardium: An exploratory study

Background: This experimental study was designed to evaluate the effects of the pharmaceutical substances U-74389G (Lazaroid) and Sildenafil, administered separately or in combination, during anaesthesia in relation to pulmonary function, in a myocardial ischaemia-reperfusion procedure. Methods: We sought to determine the effect of sildenafil and lazaroid U-74389G maleate, alone or in combination, on systemic and pulmonary tissue inflammation and oxidative stress in a pig model of myocardial ischaemia-reperfusion injury. A total of 56 pigs were divided into seven groups according to the use of sildenafil, lazaroid, or their combination, and the time of administration (prior to the induction of myocardial ischaemia or after reperfusion). Results: Both sildenafil and lazaroid U-74389G maleate, administered either 10 minutes before the induction of myocardial ischaemia or immediately after the start of reperfusion, resulted in a significant effect on several markers of systemic inflammation (p<0.05). In addition, a significant reduction in lung tissue expression of tumour necrosis factor-alpha (TNF-a) (p<0.05) was observed with sildenafil, lazaroid U-74389G maleate, and their combination, when administered either before the induction of myocardial ischaemia or after the induction of reperfusion. However, no effect on tissue oxidative stress was demonstrated. Conclusion: Sildenafil, lazaroid U-74389G maleate, and their combination led to a significant amelioration of both systemic and pulmonary tissue-specific inflammatory responses. Notably, they did not exert any significant effect against tissue oxidative stress in this model. Human mechanistic studies are required to confirm these observations.

Establishing Salvia miltiorrhiza-Derived Exosome-like Nanoparticles and Elucidating Their Role in Angiogenesis.

Exosomes are multifunctional, cell-derived nanoscale membrane vesicles. Exosomes derived from certain mammalian cells have been developed as angiogenesis promoters for the treatment of myocardial ischemia-reperfusion injury, as they possess the capability to enhance endothelial cell proliferation, migration, and angiogenesis. However, the low yield of exosomes derived from mammalian cells limits their clinical applications. Therefore, we chose to extract exosome-like nanoparticles from the traditional Chinese medicine Salvia miltiorrhiza, which has been shown to promote angiogenesis. Salvia miltiorrhiza-derived exosome-like nanoparticles offer advantages, such as being economical, easily obtainable, and high-yielding, and have an ideal particle size, Zeta potential, exosome-like morphology, and stability. Salvia miltiorrhiza-derived exosome-like nanoparticles can enhance the cell viability of Human Umbilical Vein Endothelial Cells and can promote cell migration and improve the neovascularization of the cardiac tissues of myocardial ischemia-reperfusion injury, indicating their potential as angiogenesis promoters for the treatment of myocardial ischemia-reperfusion injury.

Exercise training decreases lactylation and prevents myocardial ischemia-reperfusion injury by inhibiting YTHDF2.

Exercise improves cardiac function and metabolism. Although long-term exercise leads to circulating and micro-environmental metabolic changes, the effect of exercise on protein post-translational lactylation modifications as well as its functional relevance is unclear. Here, we report that lactate can regulate cardiomyocyte changes by improving protein lactylation levels and elevating intracellular N6-methyladenosine RNA-binding protein YTHDF2. The intrinsic disorder region of YTHDF2 but not the RNA m6A-binding activity is indispensable for its regulatory function in influencing cardiomyocyte cell size changes and oxygen glucose deprivation/re-oxygenation (OGD/R)-stimulated apoptosis via upregulating Ras GTPase-activating protein-binding protein 1 (G3BP1). Downregulation of YTHDF2 is required for exercise-induced physiological cardiac hypertrophy. Moreover, myocardial YTHDF2 inhibition alleviated ischemia/reperfusion-induced acute injury and pathological remodeling. Our results here link lactate and lactylation modifications with RNA m6A reader YTHDF2 and highlight the physiological importance of this innovative post-transcriptional intrinsic regulation mechanism of cardiomyocyte responses to exercise. Decreasing lactylation or inhibiting YTHDF2/G3BP1 might represent a promising therapeutic strategy for cardiac diseases.

ALKBH5-mediated m6A demethylation of pri-miR-199a-5p exacerbates myocardial ischemia/reperfusion injury by regulating TRAF3-mediated pyroptosis.

Myocardial ischemia‒reperfusion injury (MI/RI) is closely related to pyroptosis. alkB homolog 5 (ALKBH5) is abnormally expressed in the MI/RI models. However, the detailed molecular mechanism of ALKBH5 in MI/RI has not been elucidated. In this study, rats and H9C2 cells served as experimental subjects and received MI/R induction and H/R induction, respectively. The abundance of the targeted molecules was evaluated using RT-qPCR, Western blotting, immunohistochemistry, immunofluorescence, and enzyme-linked immunosorbent assay. The heart functions of the rats were evaluated using echocardiography, and heart injury was evaluated. Cell viability and pyroptosis were determined using cell counting Kit-8 and flow cytometry, respectively. Total m6A modification was measured using a commercial kit, and pri-miR-199a-5p m6A modification was detected by Me-RNA immunoprecipitation (RIP) assay. The interactions among the molecules were validated using RIP and luciferase experiments. ALKBH5 was abnormally highly expressed in H/R-induced H9C2 cells and MI/RI rats. ALKBH5 silencing improved injury and inhibited pyroptosis. ALKBH5 reduced pri-miR-199a-5p m6A methylation to block miR-199a-5p maturation and inhibit its expression. TNF receptor-associated Factor 3 (TRAF3) is a downstream gene of miR-199a-5p. Furthermore, in H/R-induced H9C2 cells, the miR-199a-5p inhibitor-mediated promotion of pyroptosis was reversed by ALKBH5 silencing, and the TRAF3 overexpression-mediated promotion of pyroptosis was offset by miR-199a-5p upregulation. ALKBH5 silencing inhibited pri-miR-199a-5p expression and enhanced pri-miR-199a-5p m6A modification to promote miR-199a-5p maturation and enhance its expression, thereby suppressing pyroptosis to alleviate MI/RI through decreasing TRAF3 expression.

Compound Danshen Tablets ameliorate myocardial ischemia/reperfusion injury-induced ventricular remodeling by regulating autophagy via AMPK/mTOR signaling pathway

ObjectiveLeft ventricular remodeling induced by myocardial ischemia/reperfusion injury (MI/RI) is a common cardiac dysfunction. Accumulating evidence has demonstrated that autophagy plays a vital role in protecting against ventricular remodeling. This study aims to investigate the performance of compound Danshen Tablets (CDT) in rescuing ventricular remodeling and whether autophagy as the potential mechanism. MethodsThe left anterior descending arteries of rats were temporarily ligated for 30 min to construct the MI/RI model. Ventricular remodeling was induced by reperfusion for 28 d, during which the MI/RI rats were administered CDT (300 mg/kg and 600 mg/kg), atorvastatin (2 mg/kg), and diltiazem (16 mg/kg). Cardiac function and structure were examined by echocardiography. Immunohistochemistry, Masson's trichrome staining, and hematoxylin-eosin (H & E) staining were utilized to assess the fibrosis and histological alterations in the heart tissue. The expression of autophagy-related proteins was detected using Western blotting. ResultsCDT attenuated the cardiac dysfunction, structural changes, histopathological changes and fibrosis induced by MI/RI. CDT significantly enhanced the level of Beclin1 and microtubule-associated protein 1 light chain 3 beta (LC3β), and reduced p62 levels in MI/RI rats. Moreover, CDT significantly increased the phosphorylation of AMP-activated protein kinase (AMPK) and inhibited mammalian target of rapamycin (mTOR) phosphorylation. ConclusionCDT ameliorated MI/RI-induced ventricular remodeling by activating autophagy and improving autophagic flux via the AMPK/mTOR signaling pathway.

STUB1 is acetylated by KAT5 and alleviates myocardial ischemia-reperfusion injury through LATS2-YAP-β-catenin axis

Myocardial ischemia-reperfusion injury (MIRI) is involved in the pathogenesis of multiple cardiovascular diseases. This study elucidated the biological function of lysine acetyltransferase 5 (KAT5) in cardiomyocyte pyroptosis during MIRI. Oxygen-glucose deprivation/reoxygenation and left anterior descending coronary artery ligation were used to establish MIRI models. Here we show, KAT5 and STIP1 homology and U-box-containing protein 1 (STUB1) were downregulated, while large tumor suppressor kinase 2 (LATS2) was upregulated in MIRI models. KAT5/STUB1 overexpression or LATS2 silencing repressed cardiomyocyte pyroptosis. Mechanistically, KAT5 promoted STUB1 transcription via acetylation modulation, and subsequently caused ubiquitination and degradation of LATS2, which activated YAP/β-catenin pathway. Notably, the inhibitory effect of STUB1 overexpression on cardiomyocyte pyroptosis was abolished by LATS2 overexpression or KAT5 depletion. Our findings suggest that KAT5 overexpression inhibits NLRP3-mediated cardiomyocyte pyroptosis to relieve MIRI through modulation of STUB1/LATS2/YAP/β-catenin axis, providing a potential therapeutic target for MIRI.

MiR-92a Promotes Apoptosis in Rats with Myocardial Ischemia-Reperfusion Injury via Regulating Wnt/β-Catenin Pathway

In this study, the impact of micro ribonucleic acid (miR)-92a on rats with myocardial ischemia-reperfusion injury was investigated, with a focus on its regulation of the Wnt/β-catenin pathway. A total of 36 Sprague Dawley rats were divided into three groups: a sham operation group, a model group, and a miR-92a antagomir group. The sham group underwent thoracotomy without injury, while the model and miR-92a antagomir groups were subjected to myocardial ischemiareperfusion injury and treated with saline and miR-92a antagomir, respectively. Results showed that the myocardial infarction area was significantly reduced in the miR-92a antagomir group compared to the model group. Histological analysis revealed improved myocardial tissue structure in the miR-92a antagomir group. Western blotting demonstrated elevated levels of p-GSK-3β and β-catenin in both the model and miR-92a antagomir groups, with a notable decrease in the miR-92a antagomir group compared to the model group. Additionally, miR-92a expression was higher in both the model and miR-92a antagomir groups compared to the sham group. Lastly, apoptosis rates were increased in both the model and miR-92a antagomir groups, but significantly reduced in the miR-92a antagomir group compared to the model group. Overall, these findings suggest that miR-92a exacerbates apoptosis in rats with myocardial ischemia-reperfusion injury by up-regulating the Wnt/β-catenin signaling pathway.

WITHDRAWN: Maresin-1 promotes mitochondrial function and autophagy after myocardial I/R injury by modulating the SIRT1/NRF2 signaling

Maresin-1 (MaR1) is a derived metabolite of Docosahexaenoic acid (DHA) and has been proved to play a protective role in ischemic reperfusion (I/R) damage. Nevertheless, the role and potential mechanism of MaR1 in myocardial ischemic reperfusion injury (MIRI) remain obscure. In this study, hypoxia-reoxygenation (H/R) cell model was established by hypoxia treatment. CCK-8, western blot and flow cytometry were used to estimate cell proliferation and apoptosis. LDH, CK-MB and inflammation factors were detected by corresponding kits. Mitochondrial function impairment was estimated through ROS, ATP, mPTP, OCR and JC-1 staining and DCFH-DA staining. Monodansylcadaverine (MDC) staining and western blot were carried out to identify the autophagy. In addition, the SIRT1/NRF2 signaling was estimated with western blot. The data showed that MaR1 pretreatment elevated cell viability, reduced the contents of LDH, CK-MB, and inflammation factors after H/R treatment. In addition, MaR1 mitigated the functional damage of mitochondria, ameliorated H/R-induced abnormal level of autophagy and hindered the cell apoptosis rate. MaR1 also declined the contents of pro-apoptotic proteins, and inhibited oxidative stress in H/R-challenged H9c2 cells. Meanwhile, the contents of Nuclear Nrf2, Nrf2 and SIRT1 were enhanced following MaR1 treatment. SIRT1 inhibitor Selisistat (EX-527) reversed the protective influences of MaR1 on H/R-induced H9c2 cells. To sum up, MaR1 may ameliorate H/R-stimulated H9c2 cell injury via the modulation of SIRT1/NRF2 signaling.

Scutellarin Protects against Myocardial Ischemia-reperfusion Injury by Enhancing Aerobic Glycolysis through miR-34c-5p/ALDOA Axis.

Aerobic glycolysis has recently demonstrated promising potential in mitigating the effects of ischemia-reperfusion (IR) injury. Scutellarin (Scu) possesses various cardioprotective properties that warrant investigation. To mimic IR injury in vitro, this study employed hypoxia/reoxygenation (H/R) injury. First, we conducted an assessment of the protective properties of Scu against HR in H9c2 cells, encompassing inflammation damage, apoptosis injury, and oxidative stress. Then, we verified the effects of Scu on the Warburg effect in H9c2 cells during HR injury. The findings indicated that Scu augmented aerobic glycolysis by upregulating p-PKM2/PKM2 levels. Following, we built a panel of six long noncoding RNAs and seventeen microRNAs that were reported to mediate the Warburg effect. Based on the results, miR-34c-5p was selected for further experiments. Then, we observed Scu could mitigate the HR-induced elevation of miR-34c-5p. Upregulation of miR-34c-5p could weaken the beneficial impacts of Scu in cellular viability, inflammatory damage, oxidative stress, and the facilitation of the Warburg effect. Subsequently, our investigation revealed a decrease in both ALDOA mRNA and protein levels following HR injury, which could be restored by Scu administration. Downregulation of ALDOA or Mimic of miR-34c-5p could reduce these effects induced by Scu. Scu provides cardioprotective effects against IR injury by upregulating the Warburg effect via miR-34c-5p/ALDOA.

ATF3/EGR1 regulates myocardial ischemia/reperfusion injury induced autophagy and inflammation in cardiomyocytes.

Myocardial ischemia/reperfusion injury (MIRI) is an irreversible adverse event during the management of coronary heart disease that lacks effective controls. The underlying mechanism of MIRI still requires further investigation. Recent studies have suggested that overexpression of ATF3 protects against MIRI by regulating inflammatory responses, ferroptosis, and autophagy. The downstream target of ATF3, EGR1, also showed cardioprotective properties against MIRI by promoting autophagy. Therefore, further investigating the effect of ATF3/EGR1 pathway on MIRI-induced inflammation and autophagy is needed. Cardiomyocyte MIRI model was established by challenging H9C2 cells with hypoxia/reoxygenation (H/R). The ATF3 overexpression-H/R cell model by transfecting ATF3 plasmid into the H9C2 cell line. The transcription levels of ATF3 and EGR1 were determined using RT-qPCR, the levels of TNF-α and IL-6 were determined using ELISA kits, the protein expression of LC3 I, LC3 II, and P62 was determined via WB, and microstructure of H9C2 cell was observed by transmission electron microscopy (TEM). Overexpression of ATF3 significantly downregulated Egr1 levels, indicating that EGR1 might be the target of ATF3. By upregulating ATF3 levels, the extracellular levels of the inflammatory cytokines TNF-α and IL-6 significantly decreased, and the protein expression of the autophagy markers LC3 I, LC3 II, and P62 significantly increased. TEM results revealed that the cell line in the H/R-ATF3 group exhibited a higher abundance of autophagosome enclosures of mitochondria. The results indicated that ATF3/EGR1 may alleviate inflammation and improve autophagy in an H/R-induced MIRI model of cardiomyocytes.