Dexmedetomidine (Dex) is widely used in the sedation in intensive care units and as an anesthetic adjunct. Considering the anti-inflammatory and antioxidant properties of Dex, we applied in vivo rat model as well as in vitro cardiomyocyte models (embryonic rat cardiomyocytes H9c2 cells and neonatal rat cardiomyocytes, NRCMs) to evaluate the effects of Dex against myocardial ischemia reperfusion (I/R) injury. Transcriptomic sequencing for gene expression in heart tissues from control rats and Dex-treated rats identified that genes related to fatty acid metabolism were significantly regulated by Dex. Among these genes, the elongation of long-chain fatty acids (ELOVL) family member 6 (Elovl6) was most increased upon Dex-treatment. By comparing the effects of Dex on both wild type and Elovl6-knockdown H9c2 cells and NRCMs under oxygen-glucose deprivation/reoxygenation (OGD/R) challenge, we found that Elovl6 knockdown attenuated the protection efficiency of Dex, which was supported by the cytotoxicity endpoints (cell viability and lactate dehydrogenase release) and apoptosis as well as key gene expressions. These results indicate that Dex exhibited the protective function against myocardial I/R injury via fatty acid metabolism pathways and Elovl6 plays a key role in the process, which was further confirmed using palmitate exposure in both cells, as well as in an in vivo rat model. Overall, this study systematically evaluates the protective effects of Dex on the myocardial I/R injury and provides better understanding on the fatty acid metabolism underlying the beneficial effects of Dex.

Patients with myocardial infarction have a much worse prognosis when they have myocardial ischemia-reperfusion (I/R) injury. Further research into the molecular basis of myocardial I/R injury is therefore urgently needed, as well as the identification of novel therapeutic targets and linkages to interventions. Three cysteine residues are present in DJ-1 at amino acids 46, 53, and 106 sites, with the cysteine at position 106 being the most oxidation-prone. This study sought to understand how oxidized DJ-1(C106) contributes to myocardial I/R damage. Rats\' left anterior descending branches were tied off to establish a myocardial I/R model in vivo. A myocardial I/R model in vitro was established via anoxia/reoxygenation (A/R) of H9c2 cells. The results showed that autophagy increased after I/R, accompanied by the increased expression of oxidized DJ-1 (ox-DJ-1). In contrast, after pretreatment with NAC (N-acetylcysteine, a ROS scavenger) or Comp-23 (Compound-23, a specific antioxidant binding to the C106 site of DJ-1), the levels of ox-DJ-1, autophagy and LDH release decreased, and cell survival rate increased. Furthermore, the inhibition of interaction between ox-DJ-1 and PTEN could increase PTEN phosphatase activity, inhibit the p-IKK/NF-κB/Beclin1 pathway, reduce injurious autophagy, and alleviate A/R injury. However, BA (Betulinic acid, a NF-κB agonist) was able to reverse the protective effects produced by Comp-23 pretreatment. In conclusion, ox-DJ-1 could activate detrimental autophagy through the PTEN/p-IKK/NF-κB/Beclin1 pathway and exacerbate myocardial I/R injury.

Myocardial ischemia/reperfusion (I/R) injury is closely related with cardiovascular diseases; however, the underlying pathogenic mechanisms remain not fully understood. This study sought to investigate the effect and mechanisms of PIM3 implicated in myocardial I/R injury using a rat model of myocardial I/R injury and a cell model of oxygen-glucose deprivation/reoxygenation (OGD/R) induction.
The morphology changes were detected by HE staining while cell viability was accessed by the CCK-8 method. The characteristics of ferroptosis were evaluated by ROS production, MDA content, SOD level, iron content, TfR1, FTH1, and GPX4 expression.
Myocardial I/R operation increased myocardial tissue damage in rats, while OGD/R treatment reduced the viability of H9c2 cells. Both myocardial I/R operation and OGD/R stimulation increased ferroptosis, as demonstrated by elevated ROS, MDA, iron content, decreased SOD level, upregulation of TfR1, and downregulation of FTH1 and GPX4. Additionally, myocardial I/R modeling or OGD/R treatment enhanced the expression of PIM3. Silencing of PIM3 inhibited ferroptosis, which resulted in alleviated myocardial I/R-induced damage and improved H9c2 cell survival.
Our findings highlight a vital role of PIM3 in myocardial I/R injury, indicating that PIM3-targeting ferroptosis may be a promising target for the development of novel therapies of myocardial I/R injury-associated diseases.

Necroptosis and apoptosis contribute to the pathogenesis of myocardial ischaemia/reperfusion (I/R) injury and subsequent heart failure. N-arachidonoylphenolamine (AM404) is a paracetamol lipid metabolite that has pleiotropic activity to modulate the endocannabinoid system. However, the protective role of AM404 in modulating I/R-mediated myocardial damage and the underlying mechanism remain largely unknown. A murine I/R model was generated by occlusion of the left anterior descending artery. AM404 (20 mg/kg) was injected intraperitoneally into mice at 2 and 24 h before the I/R operation. Our data revealed that AM404 administration to mice greatly ameliorated I/R-triggered impairment of myocardial performance and reduced infarct area, myocyte apoptosis, oxidative stress and inflammatory response accompanied by the reduction of receptor interacting protein kinase (RIPK)1/3- mixed lineage kinase domain-like (MLKL)-mediated necroptosis and upregulation of the immunosubunits (β2i and β5i). In contrast, administration of epoxomicin (a proteasome inhibitor) dramatically abolished AM404-dependent protection against myocardial I/R damage. Mechanistically, AM404 treatment increases β5i expression, which interacts with Pellino-1 (Peli1), an E3 ligase, to form a complex with RIPK1/3, thereby promoting their degradation, which leads to inhibition of cardiomyocyte necroptosis in the I/R heart. In conclusion, these findings demonstrate that AM404 could prevent cardiac I/R damage and may be a promising drug for the treatment of ischaemic heart disease.

Aims: Myocardial ischemia-reperfusion (I/R) injury markedly undermines the protective benefits of revascularization, contributing to ventricular dysfunction and mortality. Due to complex mechanisms, no efficient ways exist to prevent cardiomyocyte reperfusion damage. Vagus nerve stimulation (VNS) appears as a potential therapeutic intervention to alleviate myocardial I/R injury. Hence, this meta-analysis intends to elucidate the potential cellular and molecular mechanisms underpinning the beneficial impact of VNS, along with its prospective clinical implications. Methods and Results: A literature search of MEDLINE, PubMed, Embase, and Cochrane Database yielded 10 articles that satisfied the inclusion criteria. VNS was significantly correlated with a reduced infarct size following myocardial I/R injury [Weighed mean difference (WMD): 25.24, 95% confidence interval (CI): 32.24 to 18.23, p < 0.001] when compared to the control group. Despite high heterogeneity (I2 = 95.3%, p < 0.001), sensitivity and subgroup analyses corroborated the robust efficacy of VNS in limiting infarct expansion. Moreover, meta-regression failed to identify significant influences of pre-specified covariates (i.e., stimulation type or site, VNS duration, condition, and species) on the primary estimates. Notably, VNS considerably impeded ventricular remodeling and cardiac dysfunction, as evidenced by improved left ventricular ejection fraction (LVEF) (WMD: 10.12, 95% CI: 4.28; 15.97, p = 0.001) and end-diastolic pressure (EDP) (WMD: 5.79, 95% CI: 9.84; -1.74, p = 0.005) during the reperfusion phase. Conclusion: VNS offers a protective role against myocardial I/R injury and emerges as a promising therapeutic strategy for future clinical application.

BACKGROUND: Myocardial ischemia-reperfusion (I/R) injury is accompanied by an imbalance in the cardiac autonomic nervous system, characterized by over-activated sympathetic tone and reduced vagal nerve activity. In our preceding study, we pioneered the development of the magnetic vagus nerve stimulation (mVNS) system. This system showcased precise vagus nerve stimulation, demonstrating remarkable effectiveness and safety in treating myocardial infarction. However, it remains uncertain whether mVNS can mitigate myocardial I/R injury and its specific underlying mechanisms. In this study, we utilized a rat model of myocardial I/R injury to delve into the therapeutic potential of mVNS against this type of injury.
RESULTS: Our findings revealed that mVNS treatment led to a reduction in myocardial infarct size, a decrease in ventricular fibrillation (VF) incidence and a curbing of inflammatory cytokine release. Mechanistically, mVNS demonstrated beneficial effects on myocardial I/R injury by inhibiting NLRP3-mediated pyroptosis through the M2AChR/OGDHL/ROS axis.
CONCLUSIONS: Collectively, these outcomes highlight the promising potential of mVNS as a treatment strategy for myocardial I/R injury.

SIRT1 is a highly conserved nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylase. It is involved in the regulation of various pathophysiological processes, including cell proliferation, survival, differentiation, autophagy, and oxidative stress. Therapeutic activation of SIRT1 protects the heart and cardiomyocytes from pathology-related stress, particularly myocardial ischemia/reperfusion (I/R). Autophagy is an important metabolic pathway for cell survival during energy or nutrient deficiency, hypoxia, or oxidative stress. Autophagy is a double-edged sword in myocardial I/R injury. The activation of autophagy during the ischemic phase removes excess metabolic waste and helps ensure cardiomyocyte survival, whereas excessive autophagy during reperfusion depletes the cellular components and leads to autophagic cell death. Increasing research on I/R injury has indicated that SIRT1 is involved in the process of autophagy and regulates myocardial I/R. SIRT1 regulates autophagy through various pathways, such as the deacetylation of FOXOs, ATGs, and LC3. Recent studies have confirmed that SIRT1-mediated autophagy plays different roles at different stages of myocardial I/R injury. By targeting the mechanism of SIRT1-mediated autophagy at different stages of I/R injury, new small-molecule drugs, miRNA activators, or blockers can be developed. For example, resveratrol, sevoflurane, quercetin, and melatonin in the ischemic stage, coptisine, curcumin, berberine, and some miRNAs during reperfusion, were involved in regulating the SIRT1-autophagy axis, exerting a cardioprotective effect. Here, we summarize the possible mechanisms of autophagy regulation by SIRT1 in myocardial I/R injury and the related molecular drug applications to identify strategies for treating myocardial I/R injury.

UNASSIGNED: A major consequence of acute myocardial infarction is myocardial ischemia-reperfusion (I/R) injury. Collecting proof demonstrates that AXIN1 assume a basic part in different disease; however, the role of AXIN1 in I/R injury remains to a great extent obscure.
UNASSIGNED: The I/R injury model on AC16 cells was constructed. siRNA transfection was used to knockdown AXIN1. The qRT-PCR assays and western blot assays were used to detect the expression level of AXIN1 and other key proteins. CCK-8 assays and cell apoptosis assays were used to detect cell proliferation and cell apoptosis.
UNASSIGNED: AXIN1 was significantly overexpressed in an in vitro model of I/R injury. Knockdown of AXIN1 significantly restored the cell proliferation inhibition caused by IR injury, while inhibiting apoptosis and inflammation. Further mechanistic studies revealed that the transcription factor c-Myc could regulate the expression of AXIN1. The effects of I/R injury on AC16 cells after overexpression of c-Myc were reversed by knockdown of AXIN1. Meanwhile, AXIN1 could regulate the SIRT1/p53/Nrf 2 pathway.
UNASSIGNED: Our results show an important role for AXIN1 and provide new targets for avoiding and treating I/R injury.

Aims: Adaptive changes in the heart by exercise have been shown to reduce the risk of cardiovascular disease, and M2 Acetylcholine receptor (M2AChR), a receptor abundantly present on cardiac parasympathetic nerves, is closely associated with the development of cardiovascular disease. The present study intends to investigate whether exercise can regulate endoplasmic reticulum stress (ERS) and mitophagy through M2AChR to resist myocardial ischemia-reperfusion (I/R) injury and to elucidate its mechanism of action. Results: Exercise enhanced parasympathetic nerve function and increased myocardial M2AChR protein expression in I/R rats. In addition, it promoted the protein expression of MFN2 and inhibited the expression of Drp1, Chop, PINK1/Parkin, and PERK/eIF2α/ATF4 signaling pathways, effectively reducing mitophagy, ERS, and apoptosis. At the cellular level, 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR) reduced hypoxia/reoxygenation (H/R)-induced ERS through the downregulated expression of PERK/eIF2α/ATF4 pathway proteins in H9C2 cardiomyocytes. When intervened with M2AChR inhibitors, the levels of ERS and phosphorylation levels of the PERK/eIF2α/ATF4 pathway were increased in H/R cells. Innovation and Conclusion: Exercise intervention activated the parasympathetic state in rats. It inhibited myocardial mitophagy and ERS levels, and reduced myocardial apoptosis through M2AChR, thereby resisting I/R-induced myocardial injury and improving cardiac function. Antioxid. Redox Signal. 40, 209-221.

Cardiac ischemia/reperfusion (I/R) injury is a complicated pathological event, which has close association with pyroptosis. This study uncovered the regulatory mechanisms of fat mass and obesity-associated protein (FTO) in NLRP3-mediated pyroptosis during cardiac I/R injury. H9c2 cells were stimulated with oxygen-glucose deprivation/reoxygenation (OGD/R). Cell viability and pyroptosis were detected by CCK-8 and flow cytometry. Western blotting or RT-qPCR was performed to analyze target molecule expression. NLRP3 and Caspase-1 expression was observed by immunofluorescence staining. IL-18 and IL-1β production was detected by ELISA. The total m6A and m6A level of CBL was determined by dot blot assay and methylated RNA immunoprecipitation-qPCR, respectively. The interaction between IGF2BP3 and CBL mRNA was confirmed by RNA pull-down and RIP assays. The protein interaction between CBL and β-catenin and β-catenin ubiquitination were evaluated by Co-IP. Myocardial I/R model was established in rats. We determined infarct size by TTC staining and pathological changes by H&E staining. LDH, CK-MB, LVFS, and LVEF were also assessed. FTO and β-catenin were down-regulated, while CBL was up-regulated by OGD/R stimulation. FTO/β-catenin overexpression or CBL silencing restrained OGD/R-induced NLRP3 inflammasome-mediated pyroptosis. CBL repressed β-catenin expression via ubiquitination and degradation. FTO reduced the mRNA stability of CBL by inhibiting m6A modification. CBL-mediated ubiquitination and degradation of β-catenin were involved in FTO-induced pyroptosis inhibition during myocardial I/R injury. FTO inhibits NLRP3-mediated pyroptosis to attenuate myocardial I/R injury via repressing CBL-induced ubiquitination degradation of β-catenin.