Inflammasome, pyroptosis, and cytokines in myocardial ischemia-reperfusion injury

CircBAZ1B stimulates myocardial ischemia/reperfusion injury (MI/RI) by modulating miR-1252-5p/ATF3-mediated ferroptosis

Introduction

Circular RNAs (circRNAs) have been implicated in myocardial ischemia (MI)/reperfusion injury (RI), yet their essential roles in MI/RI-induced ferroptosis have not been fully elucidated. Here, we focused on the biological function and regulatory mechanism of circBAZ1B, a circRNA derived from the bromodomain adjacent to the zinc finger domain 1B (BAZ1B) gene, in MI/RI progression.

Material and methods

We used a rat model for MI/RI, assessing myocardial infarct size via electrocardiogram (ECG) and histological staining (hematoxylin and eosin [H&E] and 2,3,5-triphenyltetrazolium chloride [TTC]). Rat cardiomyoblasts (H9c2) were used for in vitro hypoxia-reoxygenation (H/R) cell model construction. Cell viability, apoptosis, lipid reactive oxygen species (ROS) levels and iron content were determined via Cell Counting Kit-8 (CCK-8) and flow cytometric assays. Gene and ferroptosis-related protein expression levels were verified by qRT-PCR and Western blotting. RNA pull-down, RNA immunoprecipitation (RIP), and a dual-luciferase reporter system were utilized for verification of the molecular interactions.

Results

The results showed that MI/RI was accompanied by ferroptosis. We also found that activating transcription factor 3 (ATF3) knockdown promoted myocardial cell viability and inhibited ferroptosis. Notably, activation of ATF3 transcription was demonstrated to upregulate the expression of its downstream target ACSL4. Functional analysis indicated that circBAZ1B promoted ATF3 expression via miR-1252-5p. In vivo experimental data further revealed that circBAZ1B suppressed cardiomyocyte activity and promoted ferroptosis, thereby facilitating MI/RI progression.

Conclusions

The circBAZ1B/miR-1252-5p/ATF3 axis is crucial in MI/RI pathogenesis through ferroptosis regulation, offering a potential therapeutic target. Inhibiting this pathway may alleviate MI/RI effects, suggesting the need for further clinical studies.

Novel cardiac extracellular matrix biomarkers in STEMI: Associations with ischemic injury and long-term mortality

BACKGROUND

We aimed to determine whether serum levels of proteins related to changes in cardiac extracellular matrix (ECM) were associated with ischemic injury assessed by cardiac magnetic resonance (CMR) and mortality in patients with ST-elevation myocardial infarction (STEMI).

METHODS

The concentrations of six ECM-related proteins (periostin, osteopontin, syndecan-1, syndecan-4, bone morphogenetic protein 7, and growth differentiation factor (GDF)-15) were measured in serum samples from patients on Day 1 and Month 4 after STEMI (n = 239). Ischemic injury was assessed by myocardial salvage index, microvascular obstruction, infarct size, and left ventricular function measured by CMR conducted during the initial admission (median 2 days after admission) and after 4 months. All-cause mortality was recorded after a median follow-up time of 70 months.

RESULTS

Levels of periostin increased from Day 1 to Month 4 after hospitalization, while the levels of GDF-15, osteopontin, syndecan-1, and syndecan-4 declined. At both time points, high levels of syndecan-1 were associated with microvascular obstruction, large infarct size, and reduced left ventricular ejection fraction, whereas high levels of syndecan-4 at Month 4 were associated with a higher myocardial salvage index and less dilatation of the left ventricle. Higher mortality rates were associated with periostin levels at both time points, low syndecan-4 levels at Month 4, or high GDF-15 levels at Month 4.

CONCLUSIONS

In patients with STEMI, we found an association between serum levels of ECM biomarkers and ischemic injury and mortality. The results provide new insight into the role ECM components play in ischemic injury following STEMI and suggests a potential for these biomarkers in prognostication after STEMI.

Mitofilin in cardiovascular diseases: Insights into the pathogenesis and potential pharmacological interventions

The impact of mitochondrial dysfunction on the pathogenesis of cardiovascular disease is increasing. However, the precise underlying mechanism remains unclear. Mitochondria produce cellular energy through oxidative phosphorylation while regulating calcium homeostasis, cellular respiration, and the production of biosynthetic chemicals. Nevertheless, problems related to cardiac energy metabolism, defective mitochondrial proteins, mitophagy, and structural changes in mitochondrial membranes can cause cardiovascular diseases via mitochondrial dysfunction. Mitofilin is a critical inner mitochondrial membrane protein that maintains cristae structure and facilitates protein transport while linking the inner mitochondrial membrane, outer mitochondrial membrane, and mitochondrial DNA transcription. Researchers believe that mitofilin may be a therapeutic target for treating cardiovascular diseases, particularly cardiac mitochondrial dysfunctions. In this review, we highlight current findings regarding the role of mitofilin in the pathogenesis of cardiovascular diseases and potential therapeutic compounds targeting mitofilin.

RAMP1 Protects Hepatocytes against Ischemia-reperfusion Injury by Inhibiting the ERK/YAP Pathway

Background and Aims

Hepatic ischemia-reperfusion injury (HIRI) is a prevalent complication of liver transplantation, partial hepatectomy, and severe infection, necessitating the development of more effective clinical strategies. Receptor activity-modifying protein 1 (RAMP1), a member of the G protein-coupled receptor adapter family, has been implicated in numerous physiological and pathological processes. The study aimed to investigate the pathogenesis of RAMP1 in HIRI.

Methods

We established a 70% liver ischemia-reperfusion model in RAMP1 knockout (KO) and wild-type mice. Liver and blood samples were collected after 0, 6, and 24 h of hypoxia/reperfusion. Liver histological and serological analyses were performed to evaluate liver damage. We also conducted in-vitro and in-vivo experiments to explore the molecular mechanism underlying RAMP1 function.

Results

Liver injury was exacerbated in RAMP1-KO mice compared with the sham group, as evidenced by increased cell death and elevated serum transaminase and inflammation levels. HIRI was promoted in RAMP1-KO mice via the induction of hepatocyte apoptosis and inhibition of proliferation. The absence of RAMP1 led to increased activation of the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) pathway and yes-associated protein (YAP) phosphorylation, ultimately promoting apoptosis. SCH772984, an ERK/MAPK phosphorylation inhibitor, and PY-60, a YAP phosphorylation inhibitor, reduced apoptosis in in-vitro and in-vivo experiments.

Conclusions

Our findings suggest that RAMP1 protects against HIRI by inhibiting ERK and YAP phosphorylation signal transduction, highlighting its potential as a therapeutic target for HIRI and providing a new avenue for intervention.

The role of the NLRP3 inflammasome and pyroptosis in cardiovascular diseases

An intense, stereotyped inflammatory response occurs in response to ischaemic and non-ischaemic injury to the myocardium. The NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome is a finely regulated macromolecular protein complex that senses the injury and triggers and amplifies the inflammatory response by activation of caspase 1; cleavage of pro-inflammatory cytokines, such as pro-IL-1β and pro-IL-18, to their mature forms; and induction of inflammatory cell death (pyroptosis). Inhibitors of the NLRP3 inflammasome and blockers of IL-1β and IL-18 activity have been shown to reduce injury to the myocardium and pericardium, favour resolution of the inflammation and preserve cardiac function. In this Review, we discuss the components of the NLRP3 inflammasome and how it is formed and activated in various ischaemic and non-ischaemic cardiac pathologies (acute myocardial infarction, cardiac dysfunction and remodelling, atherothrombosis, myocarditis and pericarditis, cardiotoxicity and cardiac sarcoidosis). We also summarize current preclinical and clinical evidence from studies of agents that target the NLRP3 inflammasome and related cytokines.

Unraveling the Molecular Mechanisms of Activated Protein C (APC) in Mitigating Reperfusion Injury and Cardiac Ischemia: a Promising Avenue for Novel Therapeutic Interventions

Ischemic heart disease, which results from plaque formation in the coronary arteries, hinders the flow of oxygenated blood to the heart, leading to ischemia. Reperfusion injury remains a significant challenge for researchers, and the mechanisms underlying myocardial ischemia-reperfusion injury (MIRI) are not entirely understood. The review directs future research into potential targets in clinical treatment based on our present understanding of the pathophysiological mechanisms of MIRI. The study provides insights into the mechanisms underlying MIRI and offers direction for future research in this area. The use of targeted therapies may hold promise in improving cardiac function in the elderly and minimizing the adverse effects of revascularization therapies. The purpose of this review is to analyze the role of activated protein C (APC) in the pathogenesis of ischemic heart disease, heart failure, and myocardial ischemia-reperfusion injury, and discuss the potential of APC-based therapeutics.

LncRNA SNHG1 alleviates myocardial ischaemia-reperfusion injury by regulating the miR-137-3p/KLF4/TRPV1 axis

AIMS

Myocardial ischaemia-reperfusion injury (MIRI) contributes to serious myocardial injury and even death. Long non-coding RNAs (lncRNAs) have been reported to play pivotal roles in the occurrence and development of MIRI. Here, the detailed molecular mechanism of lncRNA SNHG1 in MIRI was explored.

METHODS AND RESULTS

A cell model of MIRI was established through hypoxia/reoxygenation (H/R) stimulation. Cell viability and pyroptosis were evaluated utilizing MTT, PI staining, and flow cytometry. Interleukin (IL)-1β and IL-18 secretion levels were examined by ELISA. The gene and protein expression were detected by RT-qPCR and western blot, respectively. Dual luciferase reporter gene, RIP and ChIP assays were performed to analyse the molecular interactions. The results showed that lncRNA SNHG1 overexpression alleviated H/R-induced HL-1 cell pyroptosis (all P < 0.05). LncRNA SNHG1 promoted KLF4 expression by sponging miR-137-3p. miR-137-3p silencing alleviated H/R-induced pyroptosis in HL-1 cells (all P < 0.05), which was abolished by KLF4 knockdown (all P < 0.05). KLF4 activated the AKT pathway by transcriptionally activating TRPV1 in HL-1 cells (all P < 0.05). TRPV1 knockdown reversed the alleviation of SNHG1 upregulation on H/R-induced pyroptosis in HL-1 cells (all P < 0.05).

CONCLUSIONS

These results showed that lncRNA SNHG1 assuaged cardiomyocyte pyroptosis during MIRI progression by regulating the KLF4/TRPV1/AKT axis through sponging miR-137-3p. Our findings may provide novel therapeutic targets for MIRI.

Aucubin protects against myocardial ischemia-reperfusion injury by regulating STAT3/NF-κB/HMGB-1 pathway

The main characteristics of the myocardial ischemia/reperfusion injury (MI/RI) are oxidative stress, apoptosis, and an inflammatory response. Aucubin (AU) is an iridoid glycoside that possesses various biological properties and has been discovered to demonstrate antioxidant and anti-inflammatory impacts in pathological processes, such as ischemia-reperfusion. The objective of this research was to investigate if AU treatment could mitigate myocardial inflammation and apoptosis caused by ischemia/reperfusion (I/R) in both laboratory and animal models, and to elucidate its underlying mechanism. By ligating the coronary artery on the left anterior descending side, a successful MI/RI rat model was created. Additionally, H9C2 cells were subjected to hypoxia/reoxygenation (H/R) in order to imitate the injury caused by ischemia/reperfusion (I/R). Furthermore, various concentrations of AU were administered to H9C2 cells or rats before H/R stimulation or myocardial I/R surgery, respectively. In vitro, the assessment was conducted on cardiac function, inflammatory markers, and myocardial pathology. In vivo, we examined the viability of cells, as well as factors related to apoptosis and oxidative stress. Furthermore, the presence of proteins belonging to the STAT3/NF-κB/HMGB1 signaling pathway was observed both in vivo and in vitro. AU effectively improved cardiomyocyte injury caused by H/R and myocardial injury caused by I/R. Furthermore, AU suppressed the production of reactive oxygen species and inflammatory molecules (TNF-alpha, IL-1β, and IL-6) and proteins associated with cell death (caspase-3 and Bax), while enhancing the levels of anti-inflammatory agents (IL-10) and the anti-apoptotic protein Bcl-2.AU mechanistically affected the phosphorylation of STAT3 at the Ser727 site and Tyr705 following H/R by modulating the signaling pathway involving signal transducer and activator of transcription 3 (STAT3)/nuclear factor-κB (NF-κB)/high mobility group box 1 (HMGB1), while also suppressing the nuclear translocation of NF-κB p65 and HMGB1 exonucleation. In conclusion, the use of AU treatment might offer protection against myocardial infarction and injury by reducing oxidative stress, suppressing apoptosis, and mitigating inflammation. The regulation of the STAT3/NF-κB/HMGB-1 pathway may contribute to this phenomenon by affecting STAT3 phosphorylation and controlling NF-κB and HMGB-1 translocation. Contributes to identifying possible objectives for myocardial ischemia/reperfusion damage.

Preparation of VX765 sodium alginate nanogels and evaluation of their therapeutic effect via local injection on myocardial infarction in rats

Myocardial Infarction (MI) is major cause of heart failure, highlighting the critical need for effective therapeutic strategies to improve cardiac repair. This study investigated the cardioprotective effects of VX765-coated polyethyleneimine (PEI)/sodium alginate (AG) composite nanogels (AG/PEI-VX765 NGs) in a rat model of MI. Additionally, AG-VX765 NGs and PEI-VX765 nanospheres (NPs) were synthesized and tested to compare their efficacy. MI was caused in rats by ligating the left anterior descending branch of the coronary artery, and the rats were grouped and set as Sham, MI, MI + VX765, MI + AG-VX765NGs, MI + PEI-VX765NPs, and MI + AG/PEI-VX765NGs. Results demonstrate that AG/PEI-VX765NGs were non-toxic and exhibited a sustained release of VX765. In vivo, experiments demonstrated that all treatment groups significantly enhanced cardiac function, reduced infarct size, fibrosis, and apoptosis in rats with MI, with the MI + AG/PEI-VX765NGs group exhibiting the most favorable outcomes. Our findings indicate that AG/PEI-VX765NGs represent a promising therapeutic approach for MI treatment.

Rivaroxaban down-regulates pyroptosis and the TLR4/NF-κB/NLRP3 signaling pathway to promote flap survival

BACKGROUND

Flap placement remains the primary method for wound repair, but postoperative ischemic flap necrosis is of major concern. This study explored whether rivaroxaban, a factor Xa inhibitor, enhanced flap survival.

METHODS

Thirty-six rats were randomly divided into control, low-dose rivaroxaban (3 mg/kg/day), and high-dose rivaroxaban (7 mg/kg/day) groups. On postoperative day 7, the flap survival rate was analyzed and the average survival area calculated. After the rats were euthanized, immunological and molecular biological techniques were employed to assess vascular regeneration, pyroptosis, and inflammation.

RESULTS

Rivaroxaban upregulated VEGF expression, in turn enhancing angiogenesis, and it downregulated IL-1β, IL-6, and TNF-α expression, thereby mitigating inflammation. The drug also suppressed TLR4, NF-κB p65, NLRP3, caspase-1, and IL-18 syntheses, thus inhibiting pyroptosis.

CONCLUSIONS

Rivaroxaban enhanced random flap survival by down-regulating the TLR4/NF-κB/NLRP3 signaling pathway to suppress pyroptosis, promoting vascular regeneration and inhibiting inflammation.

AMPK, a key molecule regulating aging-related myocardial ischemia-reperfusion injury

Aging leads to the threat of more diseases to the biological anatomical structure and the decline of disease resistance, increasing the incidence and mortality of myocardial ischemia-reperfusion injury (MI/RI). Moreover, MI/RI promotes damage to an aging heart. Notably, 5'-adenosine monophosphate-activated protein kinase (AMPK) regulates cellular energy metabolism, stress response, and protein metabolism, participates in aging-related signaling pathways, and plays an essential role in ischemia-reperfusion (I/R) injury diseases. This study aims to introduce the aging theory, summarize the interaction between aging and MI/RI, and describe the crosstalk of AMPK in aging and MI/RI. We show how AMPK can offer protective effects against age-related stressors, lifestyle factors such as alcohol consumption and smoking, and hypertension. We also review some of the clinical prospects for the development of interventions that harness the effect of AMPK to treat MI/RI and other age-related cardiovascular diseases.

High-Density Lipoproteins at the Interface between the NLRP3 Inflammasome and Myocardial Infarction

Despite significant therapeutic advancements, morbidity and mortality following myocardial infarction (MI) remain unacceptably high. This clinical challenge is primarily attributed to two significant factors: delayed reperfusion and the myocardial injury resulting from coronary reperfusion. Following reperfusion, there is a rapid intracellular pH shift, disruption of ionic balance, heightened oxidative stress, increased activity of proteolytic enzymes, initiation of inflammatory responses, and activation of several cell death pathways, encompassing apoptosis, necroptosis, and pyroptosis. The inflammatory cell death or pyroptosis encompasses the activation of the intracellular multiprotein complex known as the NLRP3 inflammasome. High-density lipoproteins (HDL) are endogenous particles whose components can either promote or mitigate the activation of the NLRP3 inflammasome. In this comprehensive review, we explore the role of inflammasome activation in the context of MI and provide a detailed analysis of how HDL can modulate this process.

Ticagrelor alleviates pyroptosis of myocardial ischemia reperfusion-induced acute lung injury in rats: a preliminary study

Pulmonary infection is highly prevalent in patients with acute myocardial infarction undergoing percutaneous coronary intervention. However, the potential mechanism is not well characterized. Myocardial ischemia-reperfusion injury (MIRI) induces acute lung injury (ALI) related to pulmonary infection and inflammation. Recent studies have shown that pyroptosis mediates ALI in several human respiratory diseases. It is not known whether MIRI induces pyroptosis in the lungs. Furthermore, ticagrelor is a clinically approved anti-platelet drug that reduces ALI and inhibits the expression levels of several pyroptosis-associated proteins, but the effects of ticagrelor on MIRI-induced ALI have not been reported. Therefore, we investigated whether ticagrelor alleviated ALI in the rat MIRI model, and its effects on pyroptosis in the lungs. Sprague-Dawley rats were randomly divided into four groups: control, MIRI, MIRI plus low ticagrelor (30 mg/kg), and MIRI plus high ticagrelor (100 mg/kg). Hematoxylin and Eosin (HE) staining was performed on the lung sections, and the HE scores were calculated to determine the extent of lung pathology. The wet-to-dry ratio of the lung tissues were also determined. The expression levels of pyroptosis-related proteins such as NLRP3, ASC, and Cleaved caspase-1 were estimated in the lung tissues using the western blot. ELISA was used to estimate the IL-1β levels in the lungs. Immunohistochemistry was performed to determine the levels of MPO-positive neutrophils as well as the total NLRP3-positive and Cleaved caspase-1-positive areas in the lung tissues. The lung tissues from the MIRI group rats showed significantly higher HE score, wet-to-dry ratio, and the MPO-positive area compared to the control group, but these effects were attenuated by pre-treatment with ticagrelor. Furthermore, lung tissues of the MIRI group rats showed significantly higher expression levels of pyroptosis-associated proteins, including NLRP3 (2.1-fold, P < 0.05), ASC (3.0-fold, P < 0.01), and Cleaved caspase-1 (9.0-fold, P < 0.01). Pre-treatment with the high-dose of ticagrelor suppressed MIRI-induced upregulation of NLRP3 (0.46-fold, P < 0.05), ASC (0.64-fold, P < 0.01), and Cleaved caspase-1 (0.80-fold, P < 0.01). Immunohistochemistry results also confirmed that pre-treatment with ticagrelor suppressed MIRI-induced upregulation of pyroptosis in the lungs. In summary, our data demonstrated that MIRI induced ALI and upregulated pyroptosis in the rat lung tissues. Pre-treatment with ticagrelor attenuated these effects.

Cardioprotective Action of a Novel Synthetic 19,20-EDP Analog Is Sirt Dependent

ABSTRACT

Mounting evidence suggests that cytochrome P450 epoxygenase-derived metabolites of docosahexaenoic acid, called epoxydocosapentaenoic acids (EDPs), limit mitochondrial damage after cardiac injury. In particular, the 19,20-EDP regioisomer has demonstrated potent cardioprotective action. Thus, we investigated our novel synthetic 19,20-EDP analog SA-22 for protection against cardiac ischemia-reperfusion (IR) injury. Isolated C57BL/6J mouse hearts were perfused through Langendorff apparatus for 20 minutes to obtain baseline function, followed by 30 minutes of global ischemia. Hearts were then treated with vehicle, 19,20-EDP, SA-22, or SA-22 with the pan-sirtuin inhibitor nicotinamide or the SIRT3-selective inhibitor 3-(1H-1,2,3-triazol-4-yl) pyridine (3-TYP) at the start of 40 minutes reperfusion (N = 5-8). We assessed IR injury-induced changes in recovery of myocardial function, using left ventricular developed pressure and systolic and diastolic pressure change. Tissues were assessed for electron transport chain function, SIRT1 and SIRT3, optic atrophy type 1, and caspase-1. We also used H9c2 cells in an in vitro model of hypoxia/reoxygenation injury (N = 3-6). Hearts perfused with SA-22 had significantly improved postischemic left ventricular developed pressure, systolic and diastolic recovery (64% of baseline), compared with vehicle control (15% of baseline). In addition, treatment with SA-22 led to better catalytic function observed in electron transport chain and SIRT enzymes. The protective action of SA-22 resulted in reduced activation of pyroptosis in both hearts and cells after injury. Interestingly, although nicotinamide cotreatment worsened functional outcomes, cell survival, and attenuated sirtuin activity, it failed to completely attenuate SA-22-induced protection against pyroptosis, possibly indicating EDPs exert cytoprotection through pleiotropic mechanisms. In short, these data demonstrate the potential of our novel synthetic 19,20-EDP analog, SA-22, against IR/hypoxia-reoxygenation injury and justify further development of therapeutic agents based on 19,20-EDP.

Canine Model of Ischemia-Induced Ventricular Tachycardia

INTRODUCTION

Despite advances in antiarrhythmia therapies, ventricular tachycardia (VT) is a leading cause of sudden cardiac death. Investigation into the characteristics and new treatments for this arrhythmia is required to improve outcomes and a reproducible model of VT would be useful in these endeavors. We therefore created a canine model of ischemia-induced VT.

MATERIALS AND METHODS

A pacing lead was implanted in the right ventricle in canines (n = 13) and the left anterior descending artery was occluded in two locations for 2 h and subsequently released to create an ischemia-reperfusion injury. In the 10 dogs that survived the first 48 h following the initial study, a terminal study was conducted 4-7 d later and VT was induced using premature stimulation or burst pacing through the right ventricle lead. The arrhythmia was terminated using either antitachycardia pacing or a defibrillatory shock. Multiple inductions into sustained VT were attempted.

RESULTS

Sustained VT was induced in eight of 10 dogs with an average cycle length of 335 ± 70 bpm. Multiple episodes of VT were induced. Episodes of VT exhibited different electrocardiogram morphologies and cycle lengths in individual animals.

CONCLUSIONS

This canine model provides a consistent technique for inducing multiple episodes of sustained VT. It may be useful for investigating VT mechanisms and testing novel therapeutics and treatments for patients with VT.

Nanomaterials for Disease Treatment by Modulating the Pyroptosis Pathway

Pyroptosis differs significantly from apoptosis and cell necrosis as an alternative mode of programmed cell death. Its occurrence is mediated by the gasdermin protein, leading to characteristic outcomes including cell swelling, membrane perforation, and release of cell contents. Research underscores the role of pyroptosis in the etiology and progression of many diseases, making it a focus of research intervention as scientists explore ways to regulate pyroptosis pathways in disease management. Despite numerous reviews detailing the relationship between pyroptosis and disease mechanisms, few delve into recent advancements in nanomaterials as a mechanism for modulating the pyroptosis pathway to mitigate disease effects. Therefore, there is an urgent need to fill this gap and elucidate the path for the use of this promising technology in the field of disease treatment. This review article delves into recent developments in nanomaterials for disease management through pyroptosis modulation, details the mechanisms by which drugs interact with pyroptosis pathways, and highlights the promise that nanomaterial research holds in driving forward disease treatment.

Regulating pyroptosis by mesenchymal stem cells and extracellular vesicles: A promising strategy to alleviate intervertebral disc degeneration

Intervertebral disc degeneration (IVDD) is a main cause of low back pain (LBP), which can lead to disability and thus generate a heavy burden on society. IVDD is characterized by a decrease in nucleus pulposus cells (NPCs) and endogenous mesenchymal stem cells (MSCs), degradation of the extracellular matrix, macrophage infiltration, and blood vessel and nerve ingrowth. To date, the therapeutic approaches regarding IVDD mainly include conservative treatment and surgical intervention. However, both can only relieve symptoms rather than stop or revert the progression of IVDD, since the pathogenesis of IVDD is not yet clear. Pyroptosis, which is characterized by Caspase family dependence and conducted by the Gasdermin family, is a newly discovered mode of programmed cell death. Pyroptosis has been observed in NPCs, annulus fibrosus cells (AFCs), chondrocytes, MSCs, macrophages, vascular endothelial cells and neurons and may contribute to IVDD. MSCs are a kind of pluripotent stem cell that can be found in almost all tissues. MSCs have a strong ability to secrete extracellular vesicles (EVs), which contain exosomes, microvesicles and apoptotic bodies. EVs derived from MSCs play an important role in pyroptosis regulation and could be beneficial for alleviating IVDD. This review focuses on clarifying the regulation of pyroptosis to improve IVDD by MSCs and EVs derived from MSCs.

Nanocurcumin attenuates pyroptosis and inflammation through inhibiting NF-κB/GSDMD signal in high altitude-associated acute liver injury

Exposure to a hypobaric hypoxic environment at high altitudes can lead to liver injury, and mounting evidence indicates that pyroptosis and inflammation play important roles in liver injury. Curcumin (Cur) can inhibit pyroptosis and inflammation. Therefore, our purpose here was to clarify the mechanism underlying the protective effect of nanocurcumin (Ncur) and Cur in a rat model of high altitude-associated acute liver injury. Eighty healthy rats were selected and exposed to different altitudes (6000 or 7000 m) for 0, 24, 48, or 72 h. Fifty normal healthy rats were divided into normal control, high-altitude control, salidroside (40 mg/kg [Sal-40]), Cur (200 mg/kg [Cur-200]), and Ncur (25 mg/kg [Ncur-25]) groups and exposed to a high-altitude hypobaric hypoxic environment (48 h, 7000 m). Serum-liver enzyme activities (alanine transaminase, aspartate transaminase, and lactate dehydrogenase were detected and histopathology of liver injury was evaluated by hematoxylin and eosin staining, and inflammatory factors were detected in liver tissues by enzyme-linked immunosorbent assays. Pyroptosis-associated proteins (gasdermin D, gasdermin D N-terminal [GSDMD-N], pro-Caspase-1, and cleaved-Caspase-1 [cleaved-Casp1]) and inflammation-associated proteins (nuclear factor-κB [NF-κB], phospho-NF-κB [P-NF-κB], and high-mobility group protein B1 [HMGB1]) levels were analyzed by immunoblotting. Ncur and Cur inhibited increased serum-liver enzyme activities, alleviated liver injury in rats caused by high-altitude hypobaric hypoxic exposure, and downregulated inflammatory factors, including tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-18, in rat liver tissues. The level of P-NF-κB, GSDMD-N, cleaved-Casp1, and HMGB1 in rat liver tissues increased significantly after high-altitude exposure. Ncur and Cur downregulated P-NF-κB, GSDMD-N, cleaved-Casp-1, and HMGB1. Ncur and Cur may inhibit inflammatory responses and pyroptosis in a rat model of high altitude-associated acute liver injury.

Unraveling the role of galectin-3 in cardiac pathology and physiology

Galectin-3 (Gal-3) is a carbohydrate-binding protein with multiple functions. Gal-3 regulates cell growth, proliferation, and apoptosis by orchestrating cell-cell and cell-matrix interactions. It is implicated in the development and progression of cardiovascular disease, and its expression is increased in patients with heart failure. In atherosclerosis, Gal-3 promotes monocyte recruitment to the arterial wall boosting inflammation and atheroma. In acute myocardial infarction (AMI), the expression of Gal-3 increases in infarcted and remote zones from the beginning of AMI, and plays a critical role in macrophage infiltration, differentiation to M1 phenotype, inflammation and interstitial fibrosis through collagen synthesis. Genetic deficiency of Gal-3 delays wound healing, impairs cardiac remodeling and function after AMI. On the contrary, Gal-3 deficiency shows opposite results with improved remodeling and function in other cardiomyopathies and in hypertension. Pharmacologic inhibition with non-selective inhibitors is also protective in cardiac disease. Finally, we recently showed that Gal-3 participates in normal aging. However, genetic absence of Gal-3 in aged mice exacerbates pathological hypertrophy and increases fibrosis, as opposed to reduced fibrosis shown in cardiac disease. Despite some gaps in understanding its precise mechanisms of action, Gal-3 represents a potential therapeutic target for the treatment of cardiovascular diseases and the management of cardiac aging. In this review, we summarize the current knowledge regarding the role of Gal-3 in the pathophysiology of heart failure, atherosclerosis, hypertension, myocarditis, and ischemic heart disease. Furthermore, we describe the physiological role of Gal-3 in cardiac aging.

Huoxin Pill Reduces Myocardial Ischemia Reperfusion Injury in Rats via TLR4/NFκB/NLRP3 Signaling Pathway

OBJECTIVE

To explore the protective effect of Huoxin Pill (HXP) on acute myocardial ischemia-reperfusion (MIRI) injury in rats.

METHODS

Seventy-five adult SD rats were divided into the sham-operated group, model group, positive drug group (diltiazem hydrochloride, DH), high dose group (24 mg/kg, HXP-H) and low dose group (12 mg/kg, HXP-L) of Huoxin Pill (n=15 for every group) according to the complete randomization method. After 1 week of intragastric administration, the left anterior descending coronary artery of the rat's heart was ligated for 45 min and reperfused for 3 h. Serum was separated and the levels of creatine kinase (CK), creatine kinase isoenzyme (CK-MB) and lactate dehydrogenase (LDH), superoxide dismutase (SOD), and malondialdehyde (MDA), hypersensitive C-reactive protein (hs-CRP) and interleukin-1β (IL-1β) were measured. Myocardial ischemia rate, myocardial infarction rate and myocardial no-reflow rate were determined by staining with Evans blue and 2,3,5-triphenyltetrazolium chloride (TTC). Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and Bioinformatics Analysis Tool for Molecular mechANism of Traditional Chinese Medicine (BATMAN) databases were used to screen for possible active compounds of HXP and their potential therapeutic targets; the results of anti-inflammatory genes associated with MIRI were obtained from GeneCards, Drugbank, Online Mendelian Inheritance in Man (OMIM), and Therapeutic Target Datebase (TTD) databases was performed; Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment were used to analyze the intersected targets; molecular docking was performed using AutoDock Tools. Western blot was used to detect the protein expression of Toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NFκB)/NOD-like receptor protein 3 (NLRP3).

RESULTS

Compared with the model group, all doses of HXP significantly reduced the levels of LDH, CK and CK-MB (P<0.05, P<0.01); HXP significantly increased serum activity of SOD (P<0.05, P<0.01); all doses of HXP significantly reduced the levels of hs-CRP and IL-1β (P<0.05, P<0.01) and the myocardial infarction rate and myocardial no-reflow rate (P<0.01). GO enrichment analysis mainly involved positive regulation of gene expression, extracellular space and identical protein binding, KEGG pathway enrichment mainly involved PI3K-Akt signaling pathway and lipid and atherosclerosis. Molecular docking results showed that kaempferol and luteolin had a better affinity with TLR4, NFκB and NLRP3 molecules. The protein expressions of TLR4, NFκB and NLRP3 were reduced in the HXP group (P<0.01).

CONCLUSIONS

HXP has a significant protective effect on myocardial ischemia-reperfusion injury in rats, and its effect may be related to the inhibition of redox response and reduction of the inflammatory response by inhibiting the TLR4NFκB/NLRP3 signaling pathway.

Regulation of alveolar macrophage death in pulmonary fibrosis: a review

Pulmonary fibrosis (PF) is a disease in which excessive extracellular matrix (ECM) accumulation occurs in pulmonary mesenchyme, which induces the destruction of alveolar structures and poor prognosis. Macrophage death is responsible for ECM accumulation after alveolar epithelial injury in PF. Depending on the local micro-environments, macrophages can be polarized to either classically activated (M1) or alternatively activated (M2) macrophage phenotypes. In general, M1 macrophages can promote inflammation and sterilization, stop the continuous damage process and prevent excessive repair, while M2 macrophages are anti-inflammatory and promote tissue repair, and excessive M2 macrophage activity may inhibit the absorption and degradation of ECM. Emerging evidence has revealed that death forms such as pyroptosis mediated by inflammasome affect polarization direction and ultimately lead to the development of PF. Pharmacological manipulation of macrophages death signals may serve as a logical therapeutic strategy for PF. This review will focus on the current state of knowledge regarding the regulation and underlying mechanisms of macrophages and their mediators in the influence of macrophage death on the development of PF. We expect to provide help in developing effective therapeutic strategies in clinical settings.

NLRP3 Inflammasome Involvement in Heart, Liver, and Lung Diseases-A Lesson from Cytokine Storm Syndrome

Inflammation and inflammasomes have been proposed as important regulators of the host-microorganism interaction, playing a key role in morbidity and mortality due to the coronavirus disease 2019 (COVID-19) in subjects with chronic conditions and compromised immune system. The inflammasome consists of a multiprotein complex that finely regulates the activation of caspase-1 and the production and secretion of potent pro-inflammatory cytokines such as IL-1β and IL-18. The pyrin containing NOD (nucleotide-binding oligomerization domain) like receptor (NLRP) is a family of intracellular receptors, sensing patterns associated to pathogens or danger signals and NLRP3 inflammasome is the most deeply analyzed for its involvement in the innate and adaptive immune system as well as its contribution to several autoinflammatory and autoimmune diseases. It is highly expressed in leukocytes and up-regulated in sentinel cells upon inflammatory stimuli. NLRP3 expression has also been reported in B and T lymphocytes, in epithelial cells of oral and genital mucosa, in specific parenchymal cells as cardiomyocytes, and keratinocytes, and chondrocytes. It is well known that a dysregulated activation of the inflammasome is involved in the pathogenesis of different disorders that share the common red line of inflammation in their pathogenetic fingerprint. Here, we review the potential roles of the NLRP3 inflammasome in cardiovascular events, liver damage, pulmonary diseases, and in that wide range of systemic inflammatory syndromes named as a cytokine storm.

Iron deficiency in myocardial ischaemia: molecular mechanisms and therapeutic perspectives

Systemic iron deficiency (SID), even in the absence of anaemia, worsens the prognosis and increases mortality in heart failure (HF). Recent clinical-epidemiological studies, however, have shown that a myocardial iron deficiency (MID) is frequently present in cases of severe HF, even in the absence of SID and without anaemia. In addition, experimental studies have shown a poor correlation between the state of systemic and myocardial iron. MID in animal models leads to severe mitochondrial dysfunction, alterations of mitophagy, and mitochondrial biogenesis, with profound alterations in cardiac mechanics and the occurrence of a fatal cardiomyopathy, all effects prevented by intravenous administration of iron. This shifts the focus to the myocardial state of iron, in the absence of anaemia, as an important factor in prognostic worsening and mortality in HF. There is now epidemiological evidence that SID worsens prognosis and mortality also in patients with acute and chronic coronary heart disease and experimental evidence that MID aggravates acute myocardial ischaemia as well as post-ischaemic remodelling. Intravenous administration of ferric carboxymaltose (FCM) or ferric dextrane improves post-ischaemic adverse remodelling. We here review such evidence, propose that MID worsens ischaemia/reperfusion injury, and discuss possible molecular mechanisms, such as chronic hyperactivation of HIF1-α, exacerbation of cytosolic and mitochondrial calcium overload, amplified increase of mitochondrial [NADH]/[NAD+] ratio, and depletion of energy status and NAD+ content with inhibition of sirtuin 1-3 activity. Such evidence now portrays iron metabolism as a core factor not only in HF but also in myocardial ischaemia.

Magnetic vagus nerve stimulation alleviates myocardial ischemia-reperfusion injury by the inhibition of pyroptosis through the M2AChR/OGDHL/ROS axis in rats

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.

Loganin alleviates myocardial ischemia-reperfusion injury through GLP-1R/NLRP3-mediated pyroptosis pathway

Myocardial ischemia-reperfusion (I/R) injury is one of main pathological manifestations of cardiovascular outcomes related to NLRP3 inflammasome-mediated pyroptosis pathway. Loganin is an iridoid glycoside extracted from traditional Chinese medicines, which has multiple activities. However, the roles and mechanism of loganin in myocardial I/R injury remain largely unknown. The models of myocardial I/R injury were established using I/R-treated rats or OGD/R-treated H9C2 cardiomyocytes. Myocardial damage was assessed by TTC and hematoxylin-eosin staining. Pyroptosis-related marker levels were detected by immunohistochemistry, immunofluorescence and western blotting assays. Cell proliferation was examined via EdU assay. Cell apoptosis was investigated by LDH release and flow cytometry. The integrity of cell membrane was analyzed via Dil staining. GLP-1R and NLRP3 levels were detected by immunofluorescence and western blotting assays. Our results showed that loganin suppressed I/R-induced myocardial damage in rats by reducing myocardial infarct, injury and pyroptosis. In addition, loganin attenuated OGD/R-induced cardiomyocyte apoptosis through increasing cell proliferation and reducing LDH release and apoptotic rate. Loganin also mitigated OGD/R-induced cardiomyocyte pyroptosis by reducing cell membrane damage and levels of cleaved caspase-1, IL-1β and IL-18. Furthermore, loganin repressed GLP-1R/NLRP3 pathway activation in OGD/R-treated H9C2 cardiomyocytes by enhancing GLP-1R expression and decreasing NLRP3 level. GLP-1R/NLRP3 activation by GLP-1R inhibition or NLRP3 overexpression reversed the suppressive effects of loganin on OGD/R-induced cardiomyocyte pyroptosis. These data indicated that loganin prevented OGD/R-induced proliferation inhibition, apoptosis and pyroptosis in OGD/R-treated cardiomyocytes by inhibiting GLP-1R/NLRP3 activity, indicating the therapeutic potential of loganin in myocardial I/R injury.

Protective effect and mechanism of different proportions of "Danggui-Kushen" herb pair on ischemic heart disease

This study aims to investigate the protective effect and mechanism of "Danggui-Kushen" herb pair (DKHP) on ischemic heart disease (IHD). The rat model of myocardial reperfusion injury (MIRI) was established by ligation of the left anterior descending coronary artery. Rats were randomly divided into seven groups and administered orally for 7 days: control group, IHD group, DKHP1:1 group, DKHP1:2 group, DKHP2:1 group, DKHP1:3 group, DKHP3:1 group, the dosage was 2.7 g/kg. Measure electrocardiogram (ECG), myocardial infarction and injury assessment, Hematoxylin and eosin (HE) staining to evaluate myocardial injury and the protective effect of DKHP. Lactate dehydrogenase (LDH), Reactive oxygen species (ROS), IL-1β and IL-6 kit detection, immunohistochemical analysis, establishment of H9c2 cardiomyocyte hypoxia (Hypoxia) model, DKHP pretreatment for 3 h, MTT method to detect cell survival rate, cell immunofluorescence to observe NF- The expression of TLR-4, NF-κB, p-NF-κB, IKβα, p-IKβα, HIF-1α, VEGF and other genes and proteins were detected by κB nuclear translocation, mitochondrial membrane potential measurement, Western blot and Polymerase Chain Reaction (PCR). Compared with the model group, DKHP can reduce the size of myocardial infarction, reduce the levels of factors such as LDH, ROS, IL-1β and IL-6, and improve the cell survival rate; Compared with the model group, DKHP can inhibit the nuclear transfer of NF-κB and reduce mitochondrial damage; the results of immunohistochemical analysis, PCR and Western blot showed that compared with the model group, DKHP can reduce TLR-4, p-NF-κB, Expression levels of p-IKβα, HIF-1α, VEGF and other proteins. Reveal that DKHP may play a protective role in ischemic heart disease by reducing inflammation and oxidative stress damage. DKHP may have protective effect on ischemic heart disease, and its mechanism may be through reducing inflammatory response and oxidative stress damage to achieve this protective effect.

Identification of potential biomarkers associated with CD4+ T cell infiltration in myocardial ischemia-reperfusion injury using bioinformation analysis

Background

Myocardial ischemia-reperfusion injury (MIRI) is often part of clinical events such as cardiac arrest, resuscitation, and reperfusion after coronary artery occlusion. Recently, more and more studies have shown that the immune microenvironment is an integral part of ischemia-reperfusion injury (IRI), and CD4+ T-cell infiltration plays an important role, but there are no relevant molecular targets for clinical diagnosis and treatment.

Methods

The transcriptome data and matched group information were retrieved from the Gene Expression Omnibus (GEO) database. The ImmuCellAI-mouse (Immune Cell Abundance Identifier for mouse) algorithm was used to calculate each symbol's CD4+ T cell infiltration score. The time period with the greatest change in the degree of CD4+ T cell infiltration [ischemia-reperfusion 6 hours (IR6h)-ischemia-reperfusion 24 hours (IR24h)] was selected for the next analysis. Weighted gene co-expression network analysis (WGCNA) and differential expression analysis were performed to screen out CD4+ T cell-related genes and from which the gene CLEC5A was screened for the highest correlation with CD4+ T cell infiltration. The potential regulatory mechanism of CD4+ T cells in MIRI was discussed through various enrichment analysis. Finally, we analyzed the expression and molecular function (MF) of CLEC5A and its related genes in MIRI.

Results

A total of 406 CD4+ T cell-related genes were obtained by intersecting the results of WGCNA and differential expression analysis. Functional enrichment analysis indicated that the CD4+ T cell-related genes were mainly involved in chemokine signaling pathway and cell cycle. By constructing a protein-protein interaction (PPI) network, a total of 12 hub genes were identified as candidate genes for further analysis. Through the correlation analysis between the 12 candidate genes found in the PPI network and CD4+ T cell infiltration fraction, we determined the core gene CLEC5A. Finally, a gene interaction network was constructed to decipher the biological functions of CLEC5A using GeneMANIA.

Conclusions

In this study, RNA sequencing (RNA-Seq) data at different time points after reperfusion were subjected to a series of bioinformatics methods such as PPI network, WGCNA module, etc., and CLEC5A, a pivotal gene associated with CD4+ T-cells, was found, which may serve as a new target for diagnosis or treatment.

Inflammation in Myocardial Ischemia/Reperfusion Injury: Underlying Mechanisms and Therapeutic Potential

Acute myocardial infarction (MI) occurs when blood flow to the myocardium is restricted, leading to cardiac damage and massive loss of viable cardiomyocytes. Timely restoration of coronary flow is considered the gold standard treatment for MI patients and limits infarct size; however, this intervention, known as reperfusion, initiates a complex pathological process that somewhat paradoxically also contributes to cardiac injury. Despite being a sterile environment, ischemia/reperfusion (I/R) injury triggers inflammation, which contributes to infarct expansion and subsequent cardiac remodeling and wound healing. The immune response is comprised of subsets of both myeloid and lymphoid-derived cells that act in concert to modulate the pathogenesis and resolution of I/R injury. Multiple mechanisms, including altered metabolic status, regulate immune cell activation and function in the setting of acute MI, yet our understanding remains incomplete. While numerous studies demonstrated cardiac benefit following strategies that target inflammation in preclinical models, therapeutic attempts to mitigate I/R injury in patients were less successful. Therefore, further investigation leveraging emerging technologies is needed to better characterize this intricate inflammatory response and elucidate its influence on cardiac injury and the progression to heart failure.

Evaluation of time-dependent phenotypes of myocardial ischemia-reperfusion in mice

BACKGROUND

A mouse model of myocardial ischemia-reperfusion (I/R) is widely used to study myocardial ischemia-reperfusion injury (I/RI). However, few studies focus on the direct comparison of the extent of pathological events resulting from variant durations of ischemia and reperfusion process.

METHODS

A mouse model of I/RI was established by ligation and perfusion of the left anterior descending coronary artery (LAD), and the dynamic changes were recorded by electrocardiogram at different stages of I/R. Subsequently, reperfusion duration was used as a variable to directly compare the phenotypes of different myocardial injury degrees induced by 3 h, 6 h and 24 h reperfusion from myocardial infarct size, myocardial apoptosis, myocardial enzyme, and inflammatory cytokine levels.

RESULTS

All mice subjected to myocardial I/R surgery showed obvious myocardial infarction, extensive myocardial apoptosis, dynamic changes in serum myocardial enzyme and inflammatory cytokines, at least for the first 24 h of reperfusion. The infarct size and apoptosis rates gradually increased with the extension of reperfusion time. The peaks of serum myocardial enzyme and inflammatory cytokines occurred at 6 h and 3 h of reperfusion, respectively. We also established I/R mice models with 30 and 60 mins of ischemia. After 21 days of remodeling, longer periods of ischemia increased the degree of fibrosis and reduced cardiac function.

CONCLUSIONS

In summary, we conclude that reperfusion durations of 3 h, 6 h, and 24 h induces different injury phenotypes in ischemia-reperfusion mouse model. At the same time, the ischemia duration before reperfusion also affects the degree of cardiac remodeling.

Exosomes as cutting-edge therapeutics in various biomedical applications: An update on engineering, delivery, and preclinical studies

Exosomes are cell-derived nanovesicles, circulating in different body fluids, and acting as an intercellular mechanism. They can be purified from culture media of different cell types and carry an enriched content of various protein and nucleic acid molecules originating from their parental cells. It was indicated that the exosomal cargo can mediate immune responses via many signaling pathways. Over recent years, the therapeutic effects of various exosome types were broadly investigated in many preclinical studies. Herein, we present an update on recent preclinical studies on exosomes as therapeutic and/or delivery agents for various applications. The exosome origin, structural modifications, natural or loaded active ingredients, size, and research outcomes were summarized for various diseases. Overall, the present article provides an overview of the latest exosome research interests and developments to clear the way for the clinical study design and application.

Broadening horizons: The role of ferroptosis in myocardial ischemia-reperfusion injury

Ferroptosis is a novel type of regulated cell death (RCD) discovered in recent years, where abnormal intracellular iron accumulation leads to the onset of lipid peroxidation, which further leads to the disruption of intracellular redox homeostasis and triggers cell death. Iron accumulation with lipid peroxidation is considered a hallmark of ferroptosis that distinguishes it from other RCDs. Myocardial ischemia-reperfusion injury (MIRI) is a process of increased myocardial cell injury that occurs during coronary reperfusion after myocardial ischemia and is associated with high post-infarction mortality. Multiple experiments have shown that ferroptosis plays an important role in MIRI pathophysiology. This review systematically summarized the latest research progress on the mechanisms of ferroptosis. Then we report the possible link between the occurrence of MIRI and ferroptosis in cardiomyocytes. Finally, we discuss and analyze the related drugs that target ferroptosis to attenuate MIRI and its action targets, and point out the shortcomings of the current state of relevant research and possible future research directions. It is hoped to provide a new avenue for improving the prognosis of the acute coronary syndrome.

Cooling Down Inflammation in the Cardiovascular System via the Nicotinic Acetylcholine Receptor

ABSTRACT

Inflammation is a major player in many cardiovascular diseases including hypertension, atherosclerosis, myocardial infarction, and heart failure. In many individuals, these conditions coexist and mutually exacerbate each other's progression. The pathophysiology of these diseases entails the active involvement of both innate and adaptive immune cells. Immune cells that possess the α7 subunit of the nicotinic acetylcholine receptor on their surface have the potential to be targeted through both pharmacological and electrical stimulation of the cholinergic system. The cholinergic system regulates the inflammatory response to various stressors in different organ systems by systematically suppressing spleen-derived monocytes and chemokines and locally improving immune cell function. Research on the cardiovascular system has demonstrated the potential for atheroma plaque stabilization and regression as favorable outcomes. Smaller infarct size and reduced fibrosis have been associated with improved cardiac function and a decrease in adverse cardiac remodeling. Furthermore, enhanced electrical stability of the myocardium can lead to a reduction in the incidence of ventricular tachyarrhythmia. In addition, improving mitochondrial dysfunction and decreasing oxidative stress can result in less myocardial tissue damage caused by reperfusion injury. Restoring baroreflex activity and reduction in renal damage can promote blood pressure regulation and help counteract hypertension. Thus, the present review highlights the potential of nicotinic acetylcholine receptor activation as a natural approach to alleviate the adverse consequences of inflammation in the cardiovascular system.

High-dose remifentanil exacerbates myocardial ischemia-reperfusion injury through activation of calcium-sensing receptor-mediated pyroptosis

Background: The aim of this study was to investigate whether calcium-sensing receptor (CaSR) was involved in HRF-mediated exacerbation of MI/R injury through NLRP3 inflammasome activation and pyroptosis. Methods: In vivo, a rat MI/R model was established by ligating the left coronary artery, and short-term HRF exposure was induced during reoxygenation. Then, TUNEL, H&E, Masson staining, immunohistochemical (IHC) and serum levels of lactate dehydrogenase (LDH) and creatine kinase isoenzyme (CK), as well as the expression levels of CaSR and pyroptosis-related proteins in heart tissues, were measured. H9c2 cells were cultured to create a hypoxia/reoxygenation (H/R) model and exposed to different concentrations of RF. After pretreatment with the CaSR activator gadolinium chloride (GdCl3) and inhibitor NPS2143 in the H/R model and treatment with HRF, we compared cellular viability, TUNEL, cytosolic [Ca2+]i, the levels of LDH and CK, pyroptosis-related proteins and CaSR in H9c2 cells. We further researched the mechanisms of CaSR-mediated pyroptosis in the H/R+HRF model by CaSR-shRNA, Ac-YVAD-CMK, MCC950 and NAC. Results: We found that HRF significantly increased CaSR expression, rate of cell death, levels of CK and LDH, and exacerbated pyroptosis in MI/R model. In vitro, HRF increased CaSR expression, decreased viability, enhanced cytosolic [Ca2+]i and exacerbated pyroptosis in H/R cells. Pretreated with GdCl3 worsen these changes, and NPS2143, MCC950, Ac-YVAD-CMK, NAC and sh-CaSR can reversed these effects. Conclusion: Exposure to HRF for a short time exacerbates MI/R-induced injury by targeting CaSR to increase cytosolic [Ca2+]i and ROS levels, which mediate the NLRP3 inflammasome and pyroptosis.

Tanshinone IIA inhibits cardiomyocyte pyroptosis through TLR4/NF-κB p65 pathway after acute myocardial infarction

Background: Tanshinone IIA, derived from Radix Salviae Miltiorrhizae (Salvia miltiorrhiza Bunge), constitutes a significant component of this traditional Chinese medicine. Numerous studies have reported positive outcomes regarding its influence on cardiac function. However, a comprehensive comprehension of the intricate mechanisms responsible for its cardioprotective effects is still lacking. Methods: A rat model of heart failure (HF) induced by acute myocardial infarction (AMI) was established via ligation of the left anterior descending coronary artery. Rats received oral administration of tanshinone IIA (1.5 mg/kg) and captopril (10 mg/kg) for 8 weeks. Cardiac function was assessed through various evaluations. Histological changes in myocardial tissue were observed using staining techniques, including Hematoxylin and Eosin (HE), Masson, and transmission electron microscopy. Tunel staining was used to detect cell apoptosis. Serum levels of NT-pro-BNP, IL-1β, and IL-18 were quantified using enzyme-linked immunosorbent assay (ELISA). Expression levels of TLR4, NF-κB p65, and pyroptosis-related proteins were determined via western blotting (WB). H9C2 cardiomyocytes underwent hypoxia-reoxygenation (H/R) to simulate ischemia-reperfusion (I/R) injury, and cell viability and apoptosis were assessed post treatment with different tanshinone IIA concentrations (0.05 μg/ml, 0.1 μg/ml). ELISA measured IL-1β, IL-18, and LDH expression in the cell supernatant, while WB analysis evaluated TLR4, NF-κB p65, and pyroptosis-related protein levels. NF-κB p65 protein nuclear translocation was observed using laser confocal microscopy. Results: Tanshinone IIA treatment exhibited enhanced cardiac function, mitigated histological cardiac tissue damage, lowered serum levels of NT-pro-BNP, IL-1β, and IL-18, and suppressed myocardial cell apoptosis. Moreover, tanshinone IIA downregulated the expression of TLR4, NF-κB p65, IL-1β, pro-IL-1β, NLRP3, Caspase-1, and GSDMD-N pyroptosis-related proteins in myocardial tissue. Additionally, it bolstered H/R H9C2 cardiomyocyte viability, curbed cardiomyocyte apoptosis, and reduced the levels of TLR4, NF-κB p65, IL-1β, pro-IL-1β, NLRP3, Caspase-1, and GSDMD-N pyroptosis-related proteins in H/R H9C2 cells. Furthermore, it hindered NF-κB p65 protein nuclear translocation. Conclusion: These findings indicate that tanshinone IIA enhances cardiac function and alleviates myocardial injury in HF rats following AMI. Moreover, tanshinone IIA demonstrates potential suppression of cardiomyocyte pyroptosis. These effects likely arise from the inhibition of the TLR4/NF-κB p65 signaling pathway, presenting a promising therapeutic target.

The Current State of Research on Sirtuin-Mediated Autophagy in Cardiovascular Diseases

Sirtuins belong to the class III histone deacetylases and possess nicotinamide adenine dinucleotide-dependent deacetylase activity. They are involved in the regulation of multiple signaling pathways implicated in cardiovascular diseases. Autophagy is a crucial adaptive cellular response to stress stimuli. Mounting evidence suggests a strong correlation between Sirtuins and autophagy, potentially involving cross-regulation and crosstalk. Sirtuin-mediated autophagy plays a crucial regulatory role in some cardiovascular diseases, including atherosclerosis, ischemia/reperfusion injury, hypertension, heart failure, diabetic cardiomyopathy, and drug-induced myocardial damage. In this context, we summarize the research advancements pertaining to various Sirtuins involved in autophagy and the molecular mechanisms regulating autophagy. We also elucidate the biological function of Sirtuins across diverse cardiovascular diseases and further discuss the development of novel drugs that regulate Sirtuin-mediated autophagy.

Dexmedetomidine abates myocardial ischemia reperfusion injury through inhibition of pyroptosis via regulation of miR-665/MEF2D/Nrf2 axis

The current study intended to delve into the mechanisms of dexmedetomidine (Dex) in regulating myocardial pyroptosis against myocardial ischemia/reperfusion injury (MIRI). The rat MIRI models were induced by ligation/release of the coronary artery in vivo and Langendorff perfusion ex vivo. Hemodynamic parameters, infarction sizes, and histopathological changes were assessed to understand the effects of Dex on MIRI. We explored the mechanisms through functional experiments on an H9c2 cell hypoxia/reoxygenation (H/R) model. Cell viability and apoptosis were evaluated using cell counting kit 8 (CCK-8) and AV/PI dual staining respectively. The expressions of miR-665 and MEF2D mRNA were detected by qRT-PCR. Western blot was employed to determine the expression levels of pyroptosis- and signaling pathway- related proteins. The interplays between miR-665 and MEF2D were validated by Dual-luciferase reporter assays. Our findings indicated that Dex preconditioning dramatically attenuated hemodynamic derangements, infarct size, and histopathological damage in rats undergoing MIRI. Dex markedly augmented cell viability, while suppressing cell apoptosis and expressions of NLRP3, cleaved-caspase-1, ASC, GSDMD, IL-1β, and IL-18 in H9c2 cells subjected to H/R injury. MiR-665 was significantly upregulated, MEF2D and Nrf2 downregulated following H/R, whereas Dex preconditioning reversed these changes. MEF2D was validated to be a target gene of miR-665. Overexpression of miR-665 decreased the expression of MEF2D and blunted the protective effects of Dex in H9c2 cells. Moreover, the functional rescue experiment further verified that Dex regulated MEF2D/Nrf2 pathway via miR-665. In conclusion, Dex mitigates MIRI through inhibiting pyroptosis via regulating miR-665/MEF2D/Nrf2 axis.

Reducing myocardial infarction by combination of irisin and Dendrobium nobile Lindl through inhibiting nod-like receptor protein-3-related pyroptosis and activating PINK1/Parkin-mitophagy during aging

Aging, a crucial risk factor for ischemic heart disease, has negative impacts on cardioprotective mechanisms. As such, there is still an unmet requirement to explore potential therapies for improving the outcomes of myocardial ischemia/reperfusion (IR) injury in elderly subjects. Here, we aimed to confirm the cardioprotective function of irisin/Dendrobium nobile Lindl (DNL) combination therapy against myocardial IR injury in aged rats, with a focus on the involvement of pyroptosis and mitophagy. Male aged Wistar rats (22-24 months old, 400-450 g; n = 54) underwent myocardial IR or sham surgery. Before IR operation, rats were pretreated with irisin (0.5 mg/kg, intraperitoneally) and/or DNL (80 mg/kg, orally) for 1 or 4 weeks, respectively, at corresponding groups. Cardiac function, lactate dehydrogenase (LDH) and cardiac-specific isoform of troponin-I (cTn-I) levels, the expression of proteins involved in pyroptosis (nod-like receptor protein-3 (NLRP3), apoptosis-associated speck-like protein, c-caspase-1, and GSDMD-N) and mitophagy (PINK1 and Parkin), and pro-inflammatory cytokines levels were evaluated after 24 h of reperfusion. Irisin/DNL combined therapy significantly restored cardiac function and decreased LDH and cTn-I levels. It also downregulated pyroptosis-related proteins, upregulated PINK1 and Parkin, and decreased pro-inflammatory cytokines secretion. Pretreatment with Mdivi-1, as mitophagy inhibitor, abolished the cardioprotective action of dual therapy. This study revealed the cardioprotective effects of irisin/DNL combination therapy against IR-induced myocardial injury in aged rats, and also showed that the mechanism might be associated with suppression of NLRP3-related pyroptosis through enhancing the activity of the PINK1/Parkin mitophagy. This combination therapy is worthy of further detailed studies due to its potential to alleviate myocardial IR injury upon aging.

A novel survival rat model of hyperkalemia and landiolol induced cardioplegic arrest and resuscitation via cardiopulmonary bypass

OBJECTIVE

A small animal model would be an effective tool for research on the pathophysiology of cardiopulmonary bypass (CPB). However, numerous CPB models do not involve myocardial arrest and resuscitation. The aim of this research is to establish an easily achievable myocardial arrest and resuscitation CPB model through hyperkalemia and landiolol, simulating clinical cardiac surgery.

MATERIALS AND METHODS

Ten Sprague-Dawley rats were chosen for CPB. Rats underwent sevoflurane inhalation induction anesthesia and were sustained in an anesthesia state by intubation and intraperitoneal injection's of esketamine and propofol. The entire CPB circuit include a reservoir, a membrane oxygenator and a roller pump, which were connected into a complete loop via silicon tubes and infusion tube.After CPB was established through the tail artery and internal jugular vein, cardioplegic arrest was induced and maintained for 5 min at a rectum temperature of 28.5 ± 0.5°C with hyperkalemia and landiolol. Calcium chloride, epinephrine and insulin were then used for resuscitation.

RESULT

All rats successfully finished cardioplegic arrest, resuscitation procedure and survived 2 h postoperatively. Mean hematocrit during CPB was significantly lower than physiologic values of the baseline. The mean time of arrest-resuscitation and CPB was 5.4 ± 0.8 min and 98.5 ± 5.0 min. The blood gas at each detection point were in range with the normal standard requirement of CPB.

CONCLUSION

The establishment of cardioplegic arrest and resuscitation procedure via hyperkalemia and landiolol during CPB of WD rat could be achieved successfully. This animal model could be an alternative organ injury research on organ injury of patients undergoing cardiac surgery.

Advances in the study of exosomes derived from mesenchymal stem cells and cardiac cells for the treatment of myocardial infarction

Acute myocardial infarction has long been the leading cause of death in coronary heart disease, which is characterized by irreversible cardiomyocyte death and restricted blood supply. Conventional reperfusion therapy can further aggravate myocardial injury. Stem cell therapy, especially with mesenchymal stem cells (MSCs), has emerged as a promising approach to promote cardiac repair and improve cardiac function. MSCs may induce these effects by secreting exosomes containing therapeutically active RNA, proteins and lipids. Notably, normal cardiac function depends on intracardiac paracrine signaling via exosomes, and exosomes secreted by cardiac cells can partially reflect changes in the heart during disease, so analyzing these vesicles may provide valuable insights into the pathology of myocardial infarction as well as guide the development of new treatments. The present review examines how exosomes produced by MSCs and cardiac cells may influence injury after myocardial infarction and serve as therapies against such injury. Video Abstract.

A new method for the treatment of myocardial ischemia-reperfusion injury based on γδT cell-mediated immune response

Acute myocardial ischemia is a disease with high morbidity and mortality, and re-perfusion is currently the best intervention. However, re-perfusion may lead to further myocardial injury and increase the area of myocardial infarction. The mechanism of myocardial ischemia-re-perfusion injury is complex, but with more in-depth study, it has been proved that the immune system plays an important role in the process of MIRI. Among them, the γδT cell population has received increasing attention as the main early source of IL-17A in many immune response models. Because γδT cells have the characteristics of linking innate immunity and adaptive immunity,they can rapidly produce IL-17A and produce subsequent immune killing of cardiomyocytes. It can be seen that γδT cells play an important role in MIRI. Therefore, here we review the research progress of immune response in myocardial ischemia-re-perfusion injury, the key characteristics of γδT cells and the role of rapidly produced IL-17 in myocardial ischemia-re-perfusion injury, and propose relevant treatment strategies and prospects for myocardial repair, in order to provide new ideas and methods for clinical treatment of myocardial ischemia-re-perfusion injury.

Recombinant Apyrase (AZD3366) Against Myocardial Reperfusion Injury

PURPOSE

Recombinant apyrase (AZD3366) increases adenosine production and ticagrelor inhibits adenosine reuptake. We investigated whether intravenous AZD3366 before reperfusion reduces myocardial infarct size (IS) and whether AZD3366 and ticagrelor have additive effects.

METHODS

Sprague-Dawley rats underwent 30 min ischemia. At 25 min of ischemia, animals received intravenous AZD3366 or vehicle. Additional animals received intravenous CGS15943 (an adenosine receptor blocker) or intraperitoneal ticagrelor. At 24 h reperfusion, IS was assessed by triphenyltetrazolium chloride. Other rats were subjected to 30 min ischemia followed by 1 h or 24 h reperfusion. Myocardial samples were assessed for adenosine levels, RT-PCR, and immunoblotting.

RESULTS

AZD3366 and ticagrelor reduced IS. The protective effect was blocked by CGS15943. The effect of AZD3366 + ticagrelor was significantly greater than AZD3366. One hour after infarction, myocardial adenosine levels significantly increased with AZD3366, but not with ticagrelor. In contrast, 24 h after infarction, adenosine levels were equally increased by AZD3366 and ticagrelor, and levels were higher in the AZD3366 + ticagrelor group. One hour after reperfusion, AZD3366 and ticagrelor equally attenuated the increase in interleukin-15 (an early inflammatory marker after ischemic cell death) levels, and their combined effects were additive. AZD3366, but not ticagrelor, significantly attenuated the increase in RIP1, RIP3, and P-MLKL (markers of necroptosis) 1 h after reperfusion. AZD3366, but not ticagrelor, significantly attenuated the increase in IL-6 and GSDMD-N (markers of pyroptosis) 1 h after reperfusion. At 24 h of reperfusion, both agents equally attenuated the increase in these markers, and their effects were additive.

CONCLUSIONS

AZD3366 attenuated inflammation, necrosis, necroptosis, and pyroptosis and limited IS. The effects of AZD3366 and ticagrelor were additive.

Clinical and Pharmacological Implications of Time to Treatment with Interleukin-1 Blockade in ST-Segment Elevation Myocardial Infarction

Interleukin-1 (IL-1) blockade with anakinra given within 12 hours from reperfusion has been shown to reduce the inflammatory response as well as prevent heart failure (HF) events in patients with STEMI. We sought to determine whether time-to-treatment influences the efficacy of anakinra on systemic inflammation and incidence of HF events in patients with STEMI. We divided the cohort in two groups base6d on the median time from percutaneous coronary intervention (PCI) to investigational drug, and analyzed the effects of anakinra on the area-under-the-curve for C reactive protein (AUC-CRP) and on incidence of the composite endpoint of death or new onset HF. We analyzed data from 139 patients: 84 (60%) treated with anakinra and 55 (40%) with placebo. The median time from PCI to investigational treatment was 271 (182-391) minutes. The AUC-CRP was significantly higher in patients receiving placebo versus anakinra both in those with time from PCI to treatment <271 minutes (222.6 [103.9-325.2] vs. 78.4 [44.3-131.2], P < 0.001) and those with time from PCI to treatment ≥271 minute (235.2 [131.4-603.4] vs. 75.5 [38.9-171.9], P < 0.001) (P > 0.05 for interaction). Anakinra significantly reduced the combined endpoint of death or new onset HF in patients with time from PCI to treatment <271 minutes (5 [11%] vs. 9n[36%], log-rank χ 2 5.985, P = 0.014) as well as in patients with time from PCI to drug ≥271 minutes (2n[5%] vs. 7 [23%], log-rank χ 2 3.995, P = 0.046) (P > 0.05 for interaction). IL-1 blockade with anakinra blunts the acute systemic inflammatory response and prevents HF events independent of time-to-treatment. SIGNIFICANCE STATEMENT: In patients with ST segment elevation presenting within 12 hours of pain onset and treated within 12 hours of reperfusion, interleukin-1 blockade with anakinra blunts the acute systemic inflammatory response, a surrogate of interleukin-1 activity, and prevents heart failure events independent of time-to-treatment.

Inhibitors of NLRP3 Inflammasome in Ischemic Heart Disease: Focus on Functional and Redox Aspects

Myocardial ischemia-reperfusion injury (MIRI) is caused by several mechanisms, including the production of reactive oxygen species (ROS), altered cellular osmolarity, and inflammatory response. Calcium overload, altered oxygen levels, and mitochondrial ROS are also involved in these MIRI processes, resulting in the irreversible opening of the mitochondrial permeability transition pore (mPTP). These mechanisms and processes are associated with NLRP3 inflammasome priming and activation, which can also induce cell death by pyroptosis through the up-regulation of the caspase-1 pathway and IL-18 release. In addition, endothelial dysfunction, both in the presence and absence of MIRI, is also accompanied by altered oxygen levels, decreased nitric oxide production, and ROS overproduction, resulting in the expression of adhesion molecules and leukocyte infiltration in which the NLRP3 inflammasome plays a central role, thus contributing, through endothelial dysfunction, to the alteration of coronary flow, typical of ischemic heart disease. Given the intricate interrelationship between ROS and NLRP3, ROS inhibitors can reduce NLRP3 inflammasome activation, while NLRP3 inhibitors can reduce oxidative stress and inflammation. NLRP3 inhibitors have been intensively studied as anti-inflammatory agents in basic cardiovascular sciences. In this review, we analyze the interrelation between ROS and NLRP3 in ischemic heart disease and the effects of some NLRP3 inhibitors as possible therapeutic agents in this disease condition. All compounds considered in this review need larger studies to confirm their appropriate use in clinical scenarios as anti-ischemic drugs.

Effect and mechanism of circHMGA2 on ferroptosis and pyroptosis in myocardial ischemia-reperfusion model CircHMGA2 exacerbates MI/R injury

Myocardial ischemia-reperfusion (MI/R) injury is a common and serious complication following reperfusion treatment for myocardial infarction (MI). Increasing evidence has verified the crucial role of circular RNAs (circRNAs) in the MI/R injury processes. The objective of this study was to investigate the effects and potential regulatory mechanisms of circHMGA2 on MI/R injury. Hypoxia/reoxygenation (H/R) models were established using human cardiac myocytes (HCMs) and mice models were induced by MI/R. The level of circHMGA2 was detected by RT-qPCR. Myocardial function was evaluated by the hemodynamic parameters, the activity of serum myocardial enzymes, HE staining and TUNEL assays. Cell proliferation was measured by CCK-8 assay. The ferrous ion (Fe²⁺) level was determined with an iron assay kit. Ferroptosis- and pyroptosis-related proteins were determined using western blotting. The levels of oxidative stress and inflammatory factors were analyzed using DCFH-DA staining or ELISA assays. CircHMGA2 was upregulated in H/R-induced HCMs and myocardial tissues of MI/R mice. In vitro, circHMGA2 knockdown attenuated the proliferation inhibition, restrained the ferroptosis and pyroptosis in H/R-induced HCMs. This regulatory mechanism may be associated with the suppression of NLRP3 pathway. In vivo, circHMGA2 depletion attenuated myocardial tissue damage of MI/R mice through inhibiting the oxidative stress and pyroptosis. Taken together, CircHMGA2 enhanced MI/R injury via promoting ferroptosis and pyroptosis, providing new insights into the treatment of MI/R injury.

Inhibition of microRNA-122 alleviates pyroptosis by targeting dual-specificity phosphatase 4 in myocardial ischemia/reperfusion injury

Pyroptosis is a type of programmed cell death that induces myocardial ischemia-reperfusion injury (I/RI), which leads to cardiac dysfunction and even lethal reperfusion injury. MiR-122 is a liver-specific miRNA associated with coronary heart disease, but its role in pyroptosis activation in myocardial I/RI remains unclear. Thus, this study aimed to determine whether miR-122 inhibition exerts myocardial I/RI protection in in vivo and in vitro models. An I/RI model was established in vivo using C57BL/J6 male mice. MiR-122 expression was upregulated in the heart tissues from the I/RI group. Quantitative results of echocardiography parameters showed that miR-122 inhibition improved cardiac function and downregulated interleukin (IL)-1β, IL-18, caspase 1, and caspase 11. However, pretransfection with recombinant adeno-associated virus type 9 encoding a DUSP4-specific siRNA (AAV9-siDUSP4) blocked the protective effects of miR-122 inhibition. A hypoxia/reoxygenation (H/R) model was established to mimic the I/R condition in vitro using H9C2 cells. Results showed that miR-122 inhibition increased superoxide dismutase activity (SOD) and cell viability and decreased malondialdehyde (MDA) level, IL-1β, IL-18, caspase 1, caspase 11, and cell death. These protective effects were abolished by transfection with DUSP4-specific siRNA. In summary, miR-122 expression is upregulated in I/RI, and miR-122 inhibition alleviates I/RI by suppressing pyroptosis through targeting DUSP4. Thus, miR-122 may be a novel therapeutic target for treating myocardial I/RI.

Polarizing Macrophage Functional Phenotype to Foster Cardiac Regeneration

There is an increasing interest in understanding the connection between the immune and cardiovascular systems, which are highly integrated and communicate through finely regulated cross-talking mechanisms. Recent evidence has demonstrated that the immune system does indeed have a key role in the response to cardiac injury and in cardiac regeneration. Among the immune cells, macrophages appear to have a prominent role in this context, with different subtypes described so far that each have a specific influence on cardiac remodeling and repair. Similarly, there are significant differences in how the innate and adaptive immune systems affect the response to cardiac damage. Understanding all these mechanisms may have relevant clinical implications. Several studies have already demonstrated that stem cell-based therapies support myocardial repair. However, the exact role that cardiac macrophages and their modulation may have in this setting is still unclear. The current need to decipher the dual role of immunity in boosting both heart injury and repair is due, at least for a significant part, to unresolved questions related to the complexity of cardiac macrophage phenotypes. The aim of this review is to provide an overview on the role of the immune system, and of macrophages in particular, in the response to cardiac injury and to outline, through the modulation of the immune response, potential novel therapeutic strategies for cardiac regeneration.

IL-38 attenuates myocardial ischemia-reperfusion injury by inhibiting macrophage inflammation

BACKGROUND

Reperfusion therapy is the most effective approach to resolve coronary occlusion, but myocardial injury caused by excessive inflammation during myocardial ischemia-reperfusion will also pose a new threat to health. Our prior study revealed the expression pattern of interleukin-38 (IL-38) in the peripheral blood serum of patients with ischemic cardiomyopathy and the role of IL-38 in acute myocardial infarction in mice. However, its role and potential mechanisms in myocardial ischemia/reperfusion injury (MIRI) remain to be determined.

METHODS AND RESULTS

The left anterior descending artery of C57BL/6 mice was transiently ligated to induce the MIRI model. We found that MIRI induced the expression of endogenous IL-38, which was mainly produced by locally infiltrating macrophages. Overexpression of IL-38 in C57BL/6 mice attenuated inflammatory injury and decreased myocardial apoptosis after myocardial ischemia-reperfusion. Furthermore, IL-38 inhibited lipopolysaccharide-induced macrophage inflammation in vitro. Cardiomyocytes cocultured with the supernatant of IL-38- and troponin I-treated macrophages showed a lower rate of apoptosis than controls.

CONCLUSIONS

IL-38 attenuates MIRI by inhibiting macrophage inflammation. This inhibitory effect may be partially achieved by inhibiting the activation of NOD-like receptor pyrin domain-related protein 3 inflammasome, resulting in decreased expression of inflammatory factors and reduced cardiomyocyte apoptosis.

[LINC00926 promotes pyroptosis of hypoxia-induced human umbilical vein vascular endothelial cells by recruiting ELAVL1]

OBJECTIVE

To investigate the regulatory role of the long non-coding RNA LINC00926 in pyroptosis of hypoxia-induced human umbilical vein vascular endothelial cells (HUVECs) and explore the molecular mechanism.

METHODS

HUVECs were transfected with a LINC00926-overexpressing plasmid (OE-LINC00926), a siRNA targeting ELAVL1, or both, followed by exposure to hypoxia (5% O2) or normoxia. The expression of LINC00926 and ELAVL1 in hypoxia-treated HUVECs was detected using real-time quantitative PCR (RT-qPCR) and Western blotting. Cell proliferation was detected using Cell Counting Kit-8 (CCK-8), and the levels of IL-1β in the cell cultures was determined with ELISA. The protein expression levels of pyroptosis-related proteins (caspase-1, cleaved caspase-1 and NLRP3) in the treated cells were analyzed using Western blotting, and the binding between LINC00926 and ELAVL1 was verified with RNA immunoprecipitation (RIP) assay.

RESULTS

Exposure to hypoxia obviously up-regulated the mRNA expression of LINC00926 and the protein expression of ELAVL1 in HUVECs, but did not affect the mRNA expression of ELAVL1. LINC00926 overexpression in the cells significantly inhibited cell proliferation, increased IL-1β level and enhanced the expressions of pyroptosis-related proteins (all P < 0.05). LINC00926 overexpression further up-regulated the protein expression of ELAVL1 in hypoxia-exposed HUVECs. The results of RIP assay confirmed the binding between LINC00926 and ELAVL1. ELAVL1 knockdown significantly decreased IL-1β level and the expressions of pyroptosis-related proteins in hypoxia-exposed HUVECs (P < 0.05), while LINC00926 overexpression partially reversed the effects of ELAVL1 knockdown.

CONCLUSION

LINC00926 promotes pyroptosis of hypoxia-induced HUVECs by recruiting ELAVL1.

[Effect of procalcitonin on lipopolysaccharide-induced expression of nucleotide-binding oligomerization domain-like receptor protein 3 and caspase-1 in human umbilical vein endothelial cells]

OBJECTIVES

To study the effect of procalcitonin (PCT) on lipopolysaccharide (LPS)-induced expression of the pyroptosis-related proteins nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) and caspase-1 in human umbilical vein endothelial cells (HUVECs).

METHODS

HUVECs were induced by LPS to establish a model of sepsis-induced inflammatory endothelial cell injury. The experiment was divided into two parts. In the first part, HUVECs were randomly divided into four groups: normal control, LPS (1 μg/mL), PCT (10 ng/mL), and LPS+PCT (n=3 each). In the second part, HUVECs were randomly grouped: normal control, LPS, and LPS+PCT of different concentrations (0.1, 1, 10, and 100 ng/mL) (n=3 each). Quantitative real-time PCR and Western blot were used to measure the mRNA and protein expression levels of NLRP3 and caspase-1 in each group.

RESULTS

In the first experiment: compared with the normal control group, the PCT, LPS, and LPS+PCT groups had significantly upregulated mRNA and protein expression levels of NLRP3 and caspase-1 (P<0.05); compared with the LPS group, the LPS+PCT group had significantly downregulated mRNA and protein expression levels of NLRP3 and caspase-1 (P<0.05). In the second experiment: compared with those in the LPS group, the mRNA and protein expression levels of NLRP3 and caspase-1 in the LPS+PCT of different concentrations groups were significantly downregulated in a concentration-dependent manner (P<0.05).

CONCLUSIONS

LPS can promote the expression of the pyroptosis-related proteins NLRP3 and caspase-1 in HUVECs, while PCT can inhibit the LPS-induced expression of the pyroptosis-related proteins NLRP3 and caspase-1 in HUVECs in a concentration-dependent manner.