FPR1 gene silencing suppresses cardiomyocyte apoptosis and ventricular remodeling in rats with ischemia/reperfusion injury through the inhibition of MAPK signaling pathway

Pro-resolving lipid mediators and therapeutic innovations in resolution of inflammation

This review summarizes findings presented at the 19th World Congress of Basic & Clinical Pharmacology 2023 (Glasgow, Scotland, July 3rd to 7th, 2023) from 8 speakers in the field of resolution of inflammation, resolution pharmacology and resolution biology. It is now accepted that the acute inflammatory response is protective to defend the host against infection or tissue injury. Acute inflammation is self-limited and programmed to be limited in space and time: this is achieved through endogenous resolution processes that ensure return to homeostasis. Resolution is brought about by agonist mediators that include specialized pro-resolving lipid mediators (SPMs) and pro-resolving proteins and peptides such as annexin A1 and angiotensin-(1-7), all acting to initiate anti-inflammatory and pro-resolving processes. If the inflammatory reaction remains unchecked through dysfunctional resolution mechanism, it can become chronic and contribute to a plethora of human diseases, including respiratory, cardiovascular, metabolic, allergic diseases, and arthritis. Herein, we discuss how non-resolving inflammation plays a role in the pathogenesis of these diseases. In addition to SPMs, we highlight the discovery, biosynthesis, biofunctions, and latest research updates on innovative therapeutics (including annexin-A1 peptide-mimetic RTP-026, small molecule FPR2 agonist BM-986235/LAR-1219, biased agonist for FPR1/FPR2 Cmpd17b, lipoxin mimetics AT-01-KG and AT-02-CT, melanocortin receptor agonist AP1189, gold nanoparticles, angiotensin-(1-7), and CD300a) that can promote resolution of inflammation directly or through modulation of SPMs production. Drug development strategies based on the biology of the resolution of inflammation can offer novel therapeutic means and/or add-on therapies for the treatment of chronic diseases.

Non-alcoholic fatty liver disease and heart failure: A comprehensive bioinformatics and Mendelian randomization analysis

AIMS

Heart failure (HF) and non-alcoholic fatty liver disease (NAFLD) are significant global health issues with a complex interrelationship. This study investigates their shared biomarkers and causal relationships using bioinformatics and Mendelian randomization (MR) approaches.

METHODS

We analysed NAFLD and HF datasets from the Gene Expression Omnibus (GEO). The GSE126848 dataset included 57 liver biopsy samples [14 healthy individuals, 12 obese subjects, 15 NAFL patients and 16 non-alcoholic steatohepatitis (NASH) patients]. The GSE24807 dataset comprised 12 NASH samples and 5 healthy controls. The GSE57338 dataset included 313 cardiac muscle samples [177 HF patients (95 ischaemic heart disease patients and 82 idiopathic dilated cardiomyopathy patients) and 136 healthy controls]. The GSE84796 dataset consisted of 10 end-stage HF patients and 7 healthy hearts procured from organ donors. We identified differentially expressed genes (DEGs) and constructed a protein-protein interaction (PPI) network. Functional pathways were elucidated through enrichment analyses using Gene Ontology (GO), the Kyoto Encyclopedia of Genes and Genomes (KEGG) and GeneMANIA annotation. Single nucleotide polymorphism (SNP) data for HF and NAFLD were sourced from genome-wide association studies (GWAS). The HF dataset included 486 160 samples (14 262 experimental and 471 898 control), and the NAFLD dataset comprised 377 988 samples (4761 experimental and 373 227 control). MR analysis investigates the causal interrelations.

RESULTS

Our analysis revealed 4032 DEGs from GSE126848 and 286 DEGs from GSE57338. The top 10 hub genes (CD163, VSIG4, CXCL10, FCER1G, FPR1, C1QB, CCR1, C1orf162, MRC1 and CD38) were significantly enriched in immune response, calcium ion concentration regulation and positive regulation of monocyte chemotaxis. CIBERSORT analysis indicated associations between these hub genes and natural killer (NK) cells and macrophages. Transcription factor (TF) target prediction for CD38, CXCL10 and CCR1 highlighted related TFs. A two-sample MR analysis confirmed a bidirectional causal relationship between NAFLD and HF. The main method [inverse variance weighted (IVW)] demonstrated a significant positive causal relationship between NAFLD and HF [P = 0.037; odds ratio (OR) = 1.024; 95% confidence interval (CI): 1.001 to 1.048]. Similarly, HF was associated with an increase in the risk of NAFLD (P < 0.001; OR = 1.117; 95% CI: 1.053 to 1.185).

CONCLUSIONS

Our findings reveal novel molecular signatures common to NAFLD and HF and confirm their bidirectional causality, highlighting the potential for targeted therapeutic interventions and prompting further investigation into their intricate relationship.

A Novel Compound Ligusticum Cycloprolactam Alleviates Neuroinflammation After Ischemic Stroke via the FPR1/NLRP3 Signaling Axis

BACKGROUND

Microglia/macrophages, as pivotal immune cells in the central nervous system (CNS), play a critical role in neuroinflammation associated with ischemic brain injury. Targeting their activation through pharmacological interventions represents a promising strategy to alleviate neurological deficits, thereby harboring significant implications for the prevention and treatment of ischemic stroke. Ligusticum cycloprolactam (LIGc), a novel monomeric derivative of traditional Chinese medicine, has shown potential as a therapeutic agent; however, its specific role in cerebral ischemic injury remains unclear.

METHODS

In vitro experiments utilized lipopolysaccharide (LPS)-induced inflammation models of RAW264.7 cells and primary mouse microglia. In vivo studies employed LPS-induced neuroinflammation models in mice and a transient middle cerebral artery occlusion (tMCAO) mouse model to evaluate the impact of LIGc on neuroinflammation and microglia/macrophage phenotypic alterations. Further elucidation of the molecular mechanisms underlying these effects was achieved through RNA-Seq analyses.

RESULTS

LIGc exhibited the capacity to attenuate LPS-induced production of pro-inflammatory markers in macrophages and microglia, facilitating their transition to an anti-inflammatory phenotype. In models of LPS-induced neuroinflammation and tMCAO, LIGc ameliorated pathological behaviors and neurological deficits while mitigating brain inflammation. RNA-seq analyses revealed formyl peptide receptor 1 (FPR1) as a critical mediator of LIGc's effects. Specifically, FPR1 enhances the pro-inflammatory phenotype of microglia/macrophages and inhibits their anti-inflammatory response by upregulating NLR family pyrin domain protein 3 (NLRP3) inflammasomes, thus aggravating inflammatory processes. Conversely, LIGc exerts anti-inflammatory effects by downregulating the FPR1/NLRP3 signaling axis. Furthermore, FPR1 overexpression or NLRP3 agonists reversed the effects of LIGc observed in this study.

CONCLUSION

Our findings suggest that LIGc holds promise in improving ischemic brain injury and neuroinflammation through modulation of microglia/macrophage polarization. Mechanistically, LIGc attenuates the pro-inflammatory phenotype and promotes the anti-inflammatory phenotype by targeting the FPR1/NLRP3 signaling pathway, ultimately reducing inflammatory responses and mitigating neurological damage.

Screening and identification of key biomarkers associated with endometriosis using bioinformatics and next-generation sequencing data analysis

Background

Endometriosis is a common cause of endometrial-type mucosa outside the uterine cavity with symptoms such as painful periods, chronic pelvic pain, pain with intercourse and infertility. However, the early diagnosis of endometriosis is still restricted. The purpose of this investigation is to identify and validate the key biomarkers of endometriosis.

Methods

Next-generation sequencing dataset GSE243039 was obtained from the Gene Expression Omnibus database, and differentially expressed genes (DEGs) between endometriosis and normal control samples were identified. After screening of DEGs, gene ontology (GO) and REACTOME pathway enrichment analyses were performed. Furthermore, a protein–protein interaction (PPI) network was constructed and modules were analyzed using the Human Integrated Protein–Protein Interaction rEference database and Cytoscape software, and hub genes were identified. Subsequently, a network between miRNAs and hub genes, and network between TFs and hub genes were constructed using the miRNet and NetworkAnalyst tool, and possible key miRNAs and TFs were predicted. Finally, receiver operating characteristic curve analysis was used to validate the hub genes.

Results

A total of 958 DEGs, including 479 upregulated genes and 479 downregulated genes, were screened between endometriosis and normal control samples. GO and REACTOME pathway enrichment analyses of the 958 DEGs showed that they were mainly involved in multicellular organismal process, developmental process, signaling by GPCR and muscle contraction. Further analysis of the PPI network and modules identified 10 hub genes, including vcam1, snca, prkcb, adrb2, foxq1, mdfi, actbl2, prkd1, dapk1 and actc1. Possible target miRNAs, including hsa-mir-3143 and hsa-mir-2110, and target TFs, including tcf3 (transcription factor 3) and clock (clock circadian regulator), were predicted by constructing a miRNA-hub gene regulatory network and TF-hub gene regulatory network.

Conclusions

This investigation used bioinformatics techniques to explore the potential and novel biomarkers. These biomarkers might provide new ideas and methods for the early diagnosis, treatment and monitoring of endometriosis.

Targeted Antioxidant Therapy Reduces Hyperglycemic Exacerbation of Myocardial Ischemia/Reperfusion Injury

INTRODUCTION

Acute hyperglycemia (HG) enhances inflammatory and oxidative stress and exacerbates myocardial infarct size during ischemia-reperfusion injury by activating splenic leukocytes. Formyl peptide receptor 1 (FPR1) on leukocytes is activated by and mediates myocardial ischemia-reperfusion injury. We hypothesize that selective FPR1 antagonist cinnamoyl-F-(D)L-F-(D)L-F (CF) or potent reducing agent tris (2-carboxyethyl) phosphine hydrochloride (TCEP) could abrogate hyperglycemic infarct exacerbation, both alone and synergistically via a novel CF-TCEP compound that would target leukocytes for antioxidative effect.

METHODS

Acute HG was induced in wild type mice with an intraperitoneal dextrose injection followed by left coronary artery occlusion (30 min) and reperfusion (60 min). In treatment groups, CF (0.1 mg/kg or 1 mg/kg), TCEP (1 mg/kg or 20 mg/kg), or the CF-TCEP conjugate (0.1 mg/kg) was administered intravenously before reperfusion. The hearts were harvested to measure infarct size (IF).

RESULTS

HG resulted in >50% increase in IF compared to euglycemic mice (52.1 ± 3.0 versus 34.0 ± 3.2%, P < 0.05). Neither CF nor TCEP independently exerted an infarct-sparing effect at lower doses (46.2 ± 2.1% or 50.9 ± 4.1%, P > 0.05 versus HG control) but at high doses, significantly attenuated IF exacerbation (23.2 ± 5.2% or 33.9 ± 3.6%, P < 0.05 versus HG control). However, the low-dose CF-TCEP conjugate significantly reduced IF (39.1 ± 1.7%, P < 0.05 versus HG control). IF was decreased to near euglycemic control levels (P > 0.05).

CONCLUSIONS

The CF-TECP conjugate synergistically attenuated HG infarct exacerbation at significantly lower respective doses of CF and TCEP. In addition to the intrinsic anti-inflammatory effect of blocking FPR1, CF is also a feasible tool for leukocyte-targeted therapy to treat IRI.

EPHB2 Knockdown Mitigated Myocardial Infarction by Inhibiting MAPK Signaling

Myocardial infarction (MI) is a common type of cardiovascular disease. The incidence of ventricular remodeling dysplasia and heart failure increases significantly after MI. The objective of this study is to investigate whether erythropoietin hepatocellular receptor B2 (EPHB2) can regulate myocardial injury after MI and explore its regulatory pathways. EPHB2 is significantly overexpressed in the heart tissues of MI mice. The downregulation of EPHB2 alleviates the cardiac function damage after MI. Knockdown EPHB2 alleviates MI-induced myocardial tissue inflammation and apoptosis, and myocardial fibrosis in mice. EPHB2 knockdown significantly inhibits the activation of mitogen activated kinase-like protein (MAPK) pathway in MI mice. Moreover, EPHB2 overexpression significantly promotes the phosphorylation of MAPK pathway-related protein, which can be reversed by MAPK-IN-1 (an MAPK inhibitor) treatment. In conclusion, silencing EPHB2 can mitigate MI-induced myocardial injury by inhibiting MAPK signaling in mice, suggesting that targeting EPHB2 can be a promising therapeutic target for MI-induced myocardial injury.

The hydrogen sulfide donor 4-carboxyphenyl-isothiocyanate decreases blood pressure and promotes cardioprotective effect through reduction of oxidative stress and nuclear factor kappa B/matrix metalloproteinase (MMP)-2 axis in hypertension

AIMS

Our aim was to evaluate whether the hydrogen sulfide (H2S) donor, 4-carboxyphenyl-isothiocyanate (4-CPI), exerts cardioprotective effect in the two kidney- one clip (2K-1C) rats through oxidative stress and MMP-2 activity attenuation and compare it with the classical H2S donor, Sodium Hydrosulfide (NaHS).

MATERIALS AND METHODS

Renovascular hypertension (two kidneys-one clip; 2K-1C) was surgically induced in male Wistar rats. After two weeks, normotensive (2K) and hypertensive rats were intraperitoneally treated with vehicle (0.6 % dimethyl sulfoxide), NaHS (0.24 mg/Kg/day) or with 4-CPI (0.24 mg/Kg/day), for more 4 weeks. Systolic blood pressure (SBP) was evaluated weekly by tail-cuff plethysmography. Heart function was assessed by using the Millar catheter. Cardiac hypertrophy and fibrosis were evaluated by hematoxylin and eosin, and Picrosirius Red staining, respectively. The H2S was analyzed using WSP-1 fluorimetry and the cardiac oxidative stress was measured by lucigenin chemiluminescence and Amplex Red. MMP-2 activity was measured by in-gel gelatin or in situ zymography assays. Nox1, gp91phox, MMP-2 and the phospho-p65 subunit (Serine 279) nuclear factor kappa B (NF-κB) levels were evaluated by Western blotting.

KEY FINDINGS

4-CPI reduced blood pressure in hypertensive rats, decreased cardiac remodeling and promoted cardioprotection through the enhancement of cardiac H2S levels. An attenuation of oxidative stress, with inactivation of the p65-NF-κB/MMP-2 axis was similarly observed after NaHS or 4-CPI treatment in 2K-1C hypertension.

SIGNIFICANCE

H2S is a mediator that promotes cardioprotective effects and decreases blood pressure, and 4-CPI seems to be a good candidate to reverse the maladaptive remodeling and cardiac dysfunction in renovascular hypertension.

FPR1: A critical gatekeeper of the heart and brain

G protein-coupled receptors (GPCRs) are currently the most widely focused drug targets in the clinic, exerting their biological functions by binding to chemicals and activating a series of intracellular signaling pathways. Formyl-peptide receptor 1 (FPR1) has a typical seven-transmembrane structure of GPCRs and can be stimulated by a large number of endogenous or exogenous ligands with different chemical properties, the first of which was identified as formyl-methionine-leucyl-phenylalanine (fMLF). Through receptor-ligand interactions, FPR1 is involved in inflammatory response, immune cell recruitment, and cellular signaling regulation in key cell types, including neutrophils, neural stem cells (NSCs), and microglia. This review outlines the critical roles of FPR1 in a variety of heart and brain diseases, including myocardial infarction (MI), ischemia/reperfusion (I/R) injury, neurodegenerative diseases, and neurological tumors, with particular emphasis on the milestones of FPR1 agonists and antagonists. Therefore, an in-depth study of FPR1 contributes to the research of innovative biomarkers, therapeutic targets for heart and brain diseases, and clinical applications.

Exosomes-Mediated Signaling Pathway: A New Direction for Treatment of Organ Ischemia-Reperfusion Injury

Ischemia reperfusion (I/R) is a common pathological process which occurs mostly in organs like the heart, brain, kidney, and lung. The injury caused by I/R gradually becomes one of the main causes of fatal diseases, which is an urgent clinical problem to be solved. Although great progress has been made in therapeutic methods, including surgical, drug, gene therapy, and transplant therapy for I/R injury, the development of effective methods to cure the injury remains a worldwide challenge. In recent years, exosomes have attracted much attention for their important roles in immune response, antigen presentation, cell migration, cell differentiation, and tumor invasion. Meanwhile, exosomes have been shown to have great potential in the treatment of I/R injury in organs. The study of the exosome-mediated signaling pathway can not only help to reveal the mechanism behind exosomes promoting reperfusion injury recovery, but also provide a theoretical basis for the clinical application of exosomes. Here, we review the research progress in utilizing various exosomes from different cell types to promote the healing of I/R injury, focusing on the classical signaling pathways such as PI3K/Akt, NF-κB, Nrf2, PTEN, Wnt, MAPK, toll-like receptor, and AMPK. The results suggest that exosomes regulate these signaling pathways to reduce oxidative stress, regulate immune responses, decrease the expression of inflammatory cytokines, and promote tissue repair, making exosomes a competitive emerging vector for treating I/R damage in organs.

Mechanistic target of rapamycin in regulating macrophage function in inflammatory cardiovascular diseases

The mechanistic target of rapamycin (mTOR) is evolutionarily conserved from yeast to humans and is one of the most fundamental pathways of living organisms. Since its discovery three decades ago, mTOR has been recognized as the center of nutrient sensing and growth, homeostasis, metabolism, life span, and aging. The role of dysregulated mTOR in common diseases, especially cancer, has been extensively studied and reported. Emerging evidence supports that mTOR critically regulates innate immune responses that govern the pathogenesis of various cardiovascular diseases. This review discusses the regulatory role of mTOR in macrophage functions in acute inflammation triggered by ischemia and in atherosclerotic cardiovascular disease (ASCVD) and heart failure with preserved ejection fraction (HFpEF), in which chronic inflammation plays critical roles. Specifically, we discuss the role of mTOR in trained immunity, immune senescence, and clonal hematopoiesis. In addition, this review includes a discussion on the architecture of mTOR, the function of its regulatory complexes, and the dual-arm signals required for mTOR activation to reflect the current knowledge state. We emphasize future research directions necessary to understand better the powerful pathway to take advantage of the mTOR inhibitors for innovative applications in patients with cardiovascular diseases associated with aging and inflammation.

Exploring the active ingredients and mechanism of Shenzhi Tongxin capsule against microvascular angina based on network pharmacology and molecular docking

BACKGROUND

Microvascular angina (MVA) substantially threatens human health, and the Shenzhi Tongxin (SZTX) capsule demonstrates a remarkable cardioprotective effect, making it a potential treatment option for MVA. However, the precise mechanism of action for this medication remains unclear. This study utilized network pharmacology and molecular docking technology to investigate the active components and potential mechanisms underlying the efficacy of the SZTX capsule in alleviating MVA.

METHODS

The main ingredients of the SZTX capsule, along with their targets proteins and potential disease targets associated with MVA, were extracted from public available databases. This study utilized the STRING database and Cytoscape 3.7.2 software to establish a protein-protein interaction network and determine key signaling pathway targets. Subsequently, the DAVID database was utilized to conduct Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes analyses on the intersection targets. To further investigate the molecular interactions, Autodock and PyMOL software were employed to perform molecular docking and visualize the resulting outcomes.

RESULTS

A total of 130 and 142 bioactive ingredients and intersection targets were identified respectively. Six core targets were obtained through protein-protein interaction network analysis. Gene Ontology enrichment analysis showed that 610 biological processes, 75 cellular components, and 92 molecular functions were involved. The results of Kyoto Encyclopedia of Genes and Genomes enrichment analyses indicated that SZTX capsule molecular mechanism in the treatment of MVA may be related to several pathways, including mitogen-activated protein kinases, PI3K-Akt, HIF-1, and others. The results of molecular docking showed that the 7 key active ingredients of SZTX capsule had good binding ability to 6 core proteins.

CONCLUSION

SZTX capsule potentially exerts its effects by targeting multiple signaling pathways, including the mitogen-activated protein kinases signaling pathway, PI3K-Akt signaling pathway, and HIF-1 signaling pathway. This multi-target approach enables SZTX capsule to inhibit inflammation, alleviate oxidative stress, regulate angiogenesis, and enhance endothelial function.

Spatial Multiplexed Protein Profiling of Cardiac Ischemia-Reperfusion Injury

BACKGROUND

Reperfusion therapy is critical to myocardial salvage in the event of a myocardial infarction but is complicated by ischemia-reperfusion injury (IRI). Limited understanding of the spatial organization of cardiac cells, which governs cellular interaction and function, has hindered the search for targeted interventions minimizing the deleterious effects of IRI.

METHODS

We used imaging mass cytometry to characterize the spatial distribution and dynamics of cell phenotypes and communities in the mouse left ventricle following IRI. Heart sections were collected from 12 cardiac segments (basal, mid-cavity, apical, and apex of the anterior, lateral, and inferior wall) and 8 time points (before ischemia [I-0H], and postreperfusion [R-0H, R-2H, R-6H, R-12H, R-1D, R-3D, R-7D]), and stained with 29 metal-isotope-tagged antibodies. Cell community analysis was performed on reconstructed images, and the most disease-relevant cell type and target protein were selected for intervention of IRI.

RESULTS

We obtained a total of 251 multiplexed images, and identified 197 063 single cells, which were grouped into 23 distinct cell communities based on the structure of cellular neighborhoods. The cellular architecture was heterogeneous throughout the ventricular wall and exhibited swift changes following IRI. Analysis of proteins with posttranslational modifications in single cells unveiled 13 posttranslational modification intensity clusters and highlighted increased H3K9me3 (tri-methylated lysine 9 of histone H3) as a key regulatory response in endothelial cells during the middle stage of IRI. Erasing H3K9 methylation, by silencing its methyltransferase Suv39h1 or overexpressing its demethylase Kdm4d in isolated endothelial cells, attenuated cardiac dysfunction and pathological remodeling following IRI. in vitro, H3K9me3 binding significantly increased at endothelial cell function-related genes upon hypoxia, suppressing tube formation, which was rescued by inhibiting H3K9me3.

CONCLUSIONS

We mapped the spatiotemporal heterogeneity of cellular phenotypes in the adult heart upon IRI, and uncovered H3K9me3 in endothelial cells as a potential therapeutic target for alleviating pathological remodeling of the heart following myocardial IRI.

ERK/HIF-1α/VEGF pathway: a molecular target of ELABELA (ELA) peptide for attenuating cardiac ischemia-reperfusion injury in rats by promoting angiogenesis

BACKGROUND

Myocardial ischemia-reperfusion (I/R) injury is caused by a chain of events such as endothelial dysfunction. This study was conducted to investigate protective effects of ELABELA against myocardial I/R in Wistar rats and clarify its possible mechanisms. METHODS AND RESULTS: MI model was established based on the left anterior descending coronary artery ligation for 30 min. Then, 5 µg/kg of ELA peptide was intraperitoneally infused in rats once per day for 4 days. Western blot assay was used to assay the expression of t-ERK1/2, and p-ERK1/2 in different groups. The amount of myocardial capillary density, the expression levels of VEGF and HIF-1α were evaluated using immunohistochemistry assay. Masson's trichrome staining was utilized to assay cardiac interstitial fibrosis. The results showed that establishment of MI significantly enhanced cardiac interstitial fibrosis and changed p-ERK1/2/ t-ERK1/2 ratio. Likewise, ELA post-treatment markedly increased myocardial capillary density, the expression of several angiogenic factors (VEGF-A, HIF-1α), and reduced cardiac interstitial fibrosis by activation of ERK1/2 signaling pathways.

CONCLUSION

Collectively, ELA peptide has ability to reduce myocardial I/R injury by promoting angiogenesis and reducing cardiac interstitial fibrosis through activating ERK/HIF-1α/VEGF pathway.

Simvastatin-loaded nano-niosomes efficiently downregulates the MAPK-NF-κB pathway during the acute phase of myocardial ischemia-reperfusion injury

BACKGROUND

Simvastatin can potentially mitigate acute inflammatory phase of myocardial ischemia-reperfusion injury. However, these effects negatively influenced by its poor bioavailability, low water solubility and high metabolism. Here, we investigated the effects of SIM-loaded nano-niosomes on a rat model of MI/R injury to find a drug delivery method to tackle the barriers.

METHODS

Nano-niosomes' characteristics were identified using dynamic light scattering and transmission electron microscopy. Fifty male Wistar rats were divided into five groups: Sham; MI/R; MI/R + nano-niosome; MI/R + SIM; MI/R + SIM-loaded nano-niosomes. Left anterior descending artery was ligated for 45 min, and 3 mg/kg SIM, nano-niosomes, or SIM-loaded nano-niosomes was intramyocardially injected ten min before the onset of reperfusion. ELISA assay was used to assess cardiac injury markers (cTnI, CK-MB) and inflammatory cytokines (TNF-α, IL-6, TGF-β, MPC-1). Expression level of MAPK-NF-κB and histopathological changes were evaluated by western blot and hematoxylin & eosin staining, respectively.

RESULTS

the size of nano-niosome was 137 nm, reached to 163 nm when simvastatin was loaded. To achieve optimized niosomes span 80, a drug/cholesterol ratio of 0.4 and seven min of sonication time was applied. Optimized entrapment efficiency of SIM-loaded nano-niosomes was 98.21%. Inflammatory cytokines and the expression level of MAPK and NF-κB were reduced in rats receiving SIM-loaded nano-niosomes compared to MI/R + SIM and MI/R + SIM-loaded nano-niosomes.

CONCLUSION

Our results showed that SIM-loaded nano-niosomes could act more efficiently than SIM in alleviating the acute inflammatory response of reperfusion injury via downregulating the activation of MAPK-NF-κB.

Mitochondria-targeted hydrogen sulfide donors versus acute oxidative gastric mucosal injury

Hydrogen sulfide (H₂S) as a gaseous molecule prevents gastrointestinal (GI)-tract against various injuries. This study aimed to evaluate for the first time the detailed molecular mechanism of mitochondria-targeting H₂S-prodrugs, AP39 and RT01 in gastroprotection against ischemia/reperfusion (I/R)-induced lesions. Wistar rats exposed to I/R were pretreated i.g. with vehicle, AP39 (0.004-2 mg/kg), RT01 (0.1 mg/kg), or with AP219 (0.1 mg/kg) as structural control without ability to release H₂S. AP39 was also administered with mTOR1 inhibitor, rapamycin (1 mg/kg i.g.). Gastric damage area was assessed micro-/macroscopically, gastric blood flow (GBF) by laser flowmetry, mRNA level of HIF-1α, GPx, SOD1, SOD2, annexin-A1, SOCS3, IL-1RA, IL-1β, IL-1R1, IL-1R2, TNFR2, iNOS by real-time PCR. Gastric mucosal and/or serum content of IL-1β, IL-4, IL-5, IL-10, G-CSF, M-CSF, VEGFA, GRO, RANTES, MIP-1α, MCP1, TNF-α, TIMP1, FABP3, GST-α, STAT3/5 and phosphorylation of mTOR, NF-κB, ERK, Akt was evaluated by microbeads-fluorescent assay. Mitochondrial complexes activities were measured biochemically. RNA damage was assessed as 8-OHG by ELISA. AP39 and RT01 reduced micro-/macroscopic gastric I/R-injury increasing GBF. AP39-gastroprotection was accompanied by maintained activity of mitochondrial complexes, prevented RNA oxidation and enhanced mRNA/protein expression of SOCS3, IL-1RA, annexin-A1, GST-α, HIF-1α. Rapamycin reversed AP-39-gastroprotection. AP39-gastroprotection was followed by decreased NF-κB, ERK, IL-1β and enhanced Akt and mTOR proteins phosphorylation. AP39-prevented gastric mucosal damage caused by I/R-injury, partly by mitochondrial complex activity maintenance. AP39-mediated attenuation of gastric mucosal oxidation, hypoxia and inflammation involved mTOR1 and Akt pathways activity and modulation of HIF-1α, GST-α, SOCS3, IL1RA and TIMP1 molecular interplay.

Integrated Bioinformatics-Based Analysis of Hub Genes and the Mechanism of Immune Infiltration Associated With Acute Myocardial Infarction

Background

Acute myocardial infarction (AMI) is a fatal disease that causes high morbidity and mortality. It has been reported that AMI is associated with immune cell infiltration. Now, we aimed to identify the potential diagnostic biomarkers of AMI and uncover the immune cell infiltration profile of AMI.

Methods

From the Gene Expression Omnibus (GEO) data set, three data sets (GSE48060, GSE60993, and GSE66360) were downloaded. Differentially expressed genes (DEGs) from AMI and healthy control samples were screened. Furthermore, DEGs were performed via gene ontology (GO) functional and kyoto encyclopedia of genes and genome (KEGG) pathway analyses. The Gene set enrichment analysis (GSEA) was used to analyze GO terms and KEGG pathways. Utilizing the Search Tool for Retrieval of Interacting Genes/Proteins (STRING) database, a protein–protein interaction (PPI) network was constructed, and the hub genes were identified. Then, the receiver operating characteristic (ROC) curves were constructed to analyze the diagnostic value of hub genes. And, the diagnostic value of hub genes was further validated in an independent data set GSE61144. Finally, CIBERSORT was used to represent the compositional patterns of the 22 types of immune cell fractions in AMI.

Results

A total of 71 DEGs were identified. These DEGs were mainly enriched in immune response and immune-related pathways. Toll-like receptor 2 (TLR2), interleukin-1B (IL1B), leukocyte immunoglobulin-like receptor subfamily B2 (LILRB2), Fc fragment of IgE receptor Ig (FCER1G), formyl peptide receptor 1 (FPR1), and matrix metalloproteinase 9 (MMP9) were identified as diagnostic markers with the value of p < 0.05. Also, the immune cell infiltration analysis indicated that TLR2, IL1B, LILRB2, FCER1G, FPR1, and MMP9 were correlated with neutrophils, monocytes, resting natural killer (NK) cells, gamma delta T cells, and CD4 memory resting T cells. The fractions of monocytes and neutrophils were significantly higher in AMI tissues than in control tissues.

Conclusion

TLR2, IL1B, LILRB2, FCER1G, FPR1, and MMP9 are involved in the process of AMI, which can be used as molecular biomarkers for the screening and diagnosis of AMI. In addition, the immune system plays a vital role in the occurrence and progression of AMI.

Inhibition of Myocardial Cell Apoptosis Is Important Mechanism for Ginsenoside in the Limitation of Myocardial Ischemia/Reperfusion Injury

Ischemic heart disease has a high mortality, and the recommended therapy is reperfusion. Nevertheless, the restoration of blood flow to ischemic tissue leads to further damage, namely, myocardial ischemia/reperfusion injury (MIRI). Apoptosis is an essential pathogenic factor in MIRI, and ginsenosides are effective in inhibiting apoptosis and alleviating MIRI. Here, we reviewed published studies on the anti-apoptotic effects of ginsenosides and their mechanisms of action in improving MIRI. Each ginsenoside can regulate multiple pathways to protect the myocardium. Overall, the involved apoptotic pathways include the death receptor signaling pathway, mitochondria signaling pathway, PI3K/Akt signaling pathway, NF-κB signaling pathway, and MAPK signaling pathway. Ginsenosides, with diverse chemical structures, regulate different apoptotic pathways to relieve MIRI. Summarizing the effects and mechanisms of ginsenosides contributes to further mechanism research studies and structure-function relationship research studies, which can help the development of new drugs. Therefore, we expect that this review will highlight the importance of ginsenosides in improving MIRI via anti-apoptosis and provide references and suggestions for further research in this field.

Formyl peptide receptor 1 promotes podocyte injury through regulation of mitogen-activated protein kinase pathways

Podocyte injury contributes to glomerular injury and is implicated in the pathogenesis of diabetic nephropathy. Formyl peptide receptor (FPR) 1 is abundantly expressed in neutrophils and mediates intracellular transport of Ca 2+. Intracellular Ca 2+ regulates pathological process in renal podocyte and plays a role in diabetic nephropathy. However, the role of formyl peptide receptor 1 in podocyte injury of diabetic nephropathy has not been reported yet. Firstly, a rat model with diabetic nephropathy was established by streptozotocin injection, and a cell model was established via high glucose treatment of mouse podocytes (MPC5). Formyl peptide receptor 1 was enhanced in streptozotocin-induced rats and high glucose-treated MPC5. Secondly, streptozotocin injection promoted the glomerular injury with decreased nephrin and podocin. However, tail injection with adenovirus containing shRNA for silencing of formyl peptide receptor 1 attenuated streptozotocin-induced glomerular injury and the decrease in nephrin and podocin. Moreover, silencing of formyl peptide receptor 1 repressed cell apoptosis of podocytes in diabetic rats and high glucose-treated MPC5. Lastly, protein expression levels of p-p38, p-ERK, and p-JNK protein were up-regulated in streptozotocin-induced rats and high glucose-treated MPC5. Silencing of formyl peptide receptor 1 attenuated high glucose-induced increase in p-p38, p-ERK, and p-JNK in MPC5, and over-expression of formyl peptide receptor 1 aggravated high glucose-induced increase in p-p38, p-ERK, and p-JNK. In conclusion, inhibition of formyl peptide receptor 1 preserved glomerular function and protected against podocyte dysfunction in diabetic nephropathy.

Identification of key molecules in recurrent miscarriage based on bioinformatics analysis

BACKGROUND

Recurrent miscarriage (RM) affects 1% to 5% of couples, and the mechanisms still stay unclear. In this study, we explored the underlying molecular mechanism and potential molecular biomarkers of RM as well as constructed a miRNA-mRNA regulation network.

METHODS

The microarray datasets GSE73025 and GSE22490, which represent mRNA and miRNA profiles, respectively, were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) with p-value < 0.05 and fold-change > 2 were identified while the miRNAs with p-value < 0.05 and fold-change > 1.3 were considered as significant differentially expressed miRNAs (DEMs).

RESULTS

A total of 373 DEGs, including 218 up-regulated genes and 155 down-regulated genes, were identified, while 138 up-regulated and 68 down-regulated DEMs were screened out. After functional enrichment analysis, we found GO biological process (BP) terms significantly enriched in the Fc-gamma receptor signaling pathway involved in phagocytosis. Moreover, signaling pathway analyses indicated that the neurotrophin signaling pathway (hsa04722) was the top KEGG enrichment. 6 hub genes (FPR1, C5AR1, CCR1, ADCY7, CXCR2, NPY) were screened out to construct a complex regulation network in RM because they had the highest degree of affecting the network. Besides, we constructed miRNA-mRNA network between DEMs target genes and DEGs in RM, including hsa-miR-1297- KLHL24 and hsa-miR-548a-5p-KLHL24 pairs.

CONCLUSIONS

In conclusion, the novel differentially expressed molecules in the present study could provide a new sight to explore the pathogenesis of RM as well as potential biomarkers and therapeutic targets for RM diagnosis and treatment.

Identification of candidate biomarkers and therapeutic agents for heart failure by bioinformatics analysis

INTRODUCTION

Heart failure (HF) is a heterogeneous clinical syndrome and affects millions of people all over the world. HF occurs when the cardiac overload and injury, which is a worldwide complaint. The aim of this study was to screen and verify hub genes involved in developmental HF as well as to explore active drug molecules.

METHODS

The expression profiling by high throughput sequencing of GSE141910 dataset was downloaded from the Gene Expression Omnibus (GEO) database, which contained 366 samples, including 200 heart failure samples and 166 non heart failure samples. The raw data was integrated to find differentially expressed genes (DEGs) and were further analyzed with bioinformatics analysis. Gene ontology (GO) and REACTOME enrichment analyses were performed via ToppGene; protein-protein interaction (PPI) networks of the DEGs was constructed based on data from the HiPPIE interactome database; modules analysis was performed; target gene-miRNA regulatory network and target gene-TF regulatory network were constructed and analyzed; hub genes were validated; molecular docking studies was performed.

RESULTS

A total of 881 DEGs, including 442 up regulated genes and 439 down regulated genes were observed. Most of the DEGs were significantly enriched in biological adhesion, extracellular matrix, signaling receptor binding, secretion, intrinsic component of plasma membrane, signaling receptor activity, extracellular matrix organization and neutrophil degranulation. The top hub genes ESR1, PYHIN1, PPP2R2B, LCK, TP63, PCLAF, CFTR, TK1, ECT2 and FKBP5 were identified from the PPI network. Module analysis revealed that HF was associated with adaptive immune system and neutrophil degranulation. The target genes, miRNAs and TFs were identified from the target gene-miRNA regulatory network and target gene-TF regulatory network. Furthermore, receiver operating characteristic (ROC) curve analysis and RT-PCR analysis revealed that ESR1, PYHIN1, PPP2R2B, LCK, TP63, PCLAF, CFTR, TK1, ECT2 and FKBP5 might serve as prognostic, diagnostic biomarkers and therapeutic target for HF. The predicted targets of these active molecules were then confirmed.

CONCLUSION

The current investigation identified a series of key genes and pathways that might be involved in the progression of HF, providing a new understanding of the underlying molecular mechanisms of HF.

Regulation of Inflammation and Oxidative Stress by Formyl Peptide Receptors in Cardiovascular Disease Progression

G protein-coupled receptors (GPCRs) are the most important regulators of cardiac function and are commonly targeted for medical therapeutics. Formyl-Peptide Receptors (FPRs) are members of the GPCR superfamily and play an emerging role in cardiovascular pathologies. FPRs can modulate oxidative stress through nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent reactive oxygen species (ROS) production whose dysregulation has been observed in different cardiovascular diseases. Therefore, many studies are focused on identifying molecular mechanisms of the regulation of ROS production. FPR1, FPR2 and FPR3 belong to the FPRs family and their stimulation triggers phosphorylation of intracellular signaling molecules and nonsignaling proteins that are required for NADPH oxidase activation. Some FPR agonists trigger inflammatory processes, while other ligands activate proresolving or anti-inflammatory pathways, depending on the nature of the ligands. In general, bacterial and mitochondrial formylated peptides activate a proinflammatory cell response through FPR1, while Annexin A1 and Lipoxin A4 are anti-inflammatory FPR2 ligands. FPR2 can also trigger a proinflammatory pathway and the switch between FPR2-mediated pro- and anti-inflammatory cell responses depends on conformational changes of the receptor upon ligand binding. Here we describe the detrimental or beneficial effects of the main FPR agonists and their potential role as new therapeutic and diagnostic targets in the progression of cardiovascular diseases.

Cryptotanshinone Attenuates Ischemia/Reperfusion-induced Apoptosis in Myocardium by Upregulating MAPK3

ABSTRACT

Chinese people have used the root of Salvia miltiorrhiza Bunge (called "Danshen" in Chinese) for centuries as an anticancer agent, anti-inflammatory agent, antioxidant, and cardiovascular disease drug. In addition, Danshen is considered to be a drug that can improve ischemia/reperfusion (I/R)-induced myocardium injury in traditional Chinese medicine. However, Danshen is a mixture that includes various bioactive substances. In this study, we aimed to identify the protective component and mechanism of Danshen on myocardium through network pharmacology and molecular simulation methods. First, cryptotanshinone (CTS) was identified as a potential active compound from Danshen that was associated with apoptosis by a network pharmacology approach. Subsequently, biological experiments validated that CTS inhibited ischemia/reperfusion-induced cardiomyocyte apoptosis in vivo and in vitro. Molecular docking techniques were used to screen key target information. Based on the simulative results, MAPKs were verified as well-connected molecules of CTS. Western blotting assays also demonstrated that CTS could enhance MAPK expression. Furthermore, we demonstrated that inhibition of the MAPK pathway reversed the CTS-mediated effect on cardiomyocyte apoptosis. Altogether, our work screened out CTS from Danshen and demonstrated that it protected cardiomyocytes from apoptosis.

No impact of cancer and plague-relevant FPR1 polymorphisms on COVID-19

Formyl peptide receptor 1 (FPR1) is a pattern-recognition receptor that detects bacterial as well as endogenous danger-associated molecular patterns to trigger innate immune responses by myeloid cells. A single nucleotide polymorphism, rs867228 (allelic frequency 19–20%), in the gene coding for FPR1 accelerates the manifestation of multiple carcinomas, likely due to reduced anticancer immunosurveillance secondary to a defect in antigen presentation by dendritic cells. Another polymorphism in FPR1, rs5030880 (allelic frequency 12–13%), has been involved in the resistance to plague, correlating with the fact that FPR1 is the receptor for Yersinia pestis. Driven by the reported preclinical effects of FPR1 on lung inflammation and fibrosis, we investigated whether rs867228 or rs5030880 would affect the severity of coronavirus disease-19 (COVID-19). Data obtained on patients from two different hospitals in Paris refute the hypothesis that rs867228 or rs5030880 would affect the severity of COVID-19.

The role of neutrophil extracellular traps and TLR signaling in skeletal muscle ischemia reperfusion injury

Ischemia reperfusion (IR) injury results in devastating skeletal muscle fibrosis. Here, we recapitulate this injury with a mouse model of hindlimb IR injury which leads to skeletal muscle fibrosis. Injury resulted in extensive immune infiltration with robust neutrophil extracellular trap (NET) formation in the skeletal muscle, however, direct targeting of NETs via the peptidylarginine deiminase 4 (PAD4) mechanism was insufficient to reduce muscle fibrosis. Circulating levels of IL-10 and TNFα were significantly elevated post injury, indicating toll-like receptor (TLR) signaling may be involved in muscle injury. Administration of hydroxychloroquine (HCQ), a small molecule inhibitor of TLR7/8/9, following injury reduced NET formation, IL-10, and TNFα levels and ultimately mitigated muscle fibrosis and improved myofiber regeneration following IR injury. HCQ treatment decreased fibroadipogenic progenitor cell proliferation and partially inhibited ERK1/2 phosphorylation in the injured tissue, suggesting it may act through a combination of TLR7/8/9 and ERK signaling mechanisms. We demonstrate that treatment with FDA-approved HCQ leads to decreased muscle fibrosis and increased myofiber regeneration following IR injury, suggesting short-term HCQ treatment may be a viable treatment to prevent muscle fibrosis in ischemia reperfusion and traumatic extremity injury.

Sevoflurane prevents vulnerable plaque disruption in apolipoprotein E-knockout mice by increasing collagen deposition and inhibiting inflammation

BACKGROUND

Sevoflurane may reduce the occurrence of major adverse cardiovascular events (MACCEs) in surgical patients, although the mechanisms are poorly understood. We hypothesised that sevoflurane stabilises atherosclerotic plaques by inhibiting inflammation and enhancing prolyl-4-hydroxylase α1 (P4Hα1), the rate-limiting subunit for the P4H enzyme essential for collagen synthesis.

METHODS

We established a vulnerable arterial plaque model in apolipoprotein E-knockout mice (ApoE^-/-) fed a high-fat diet that underwent daily restraint/noise stress, with/without a single prior exposure to sevoflurane for 6 h (1-3%; n=30 per group). In vitro, smooth muscle cells (SMCs) were incubated with tumour necrosis factor-alpha in the presence/absence of sevoflurane. Immunohistochemistry, immunoblots, and mRNA concentrations were used to quantify the effect of sevoflurane on plaque formation, expression of inflammatory cytokines, P4Hα1, and collagen subtypes in atherosclerotic plaques or isolated SMCs.

RESULTS

In ApoE^-/- mice, inhalation of sevoflurane 1-3% for 6 h reduced the aortic plaque size by 8-29% in a dose-dependent manner, compared with control mice that underwent restraint stress alone (P<0.05); this was associated with reduced macrophage infiltration and lower lipid concentrations in plaques. Sevoflurane reduced gene transcription and protein expression levels of pro-inflammatory cytokines (≥69-75%; P<0.05) and matrix metalloproteinases (≥39-65%; P<0.05) at both gene transcription and protein levels, compared with controls. Sevoflurane dose dependently increased Types I and III collagen deposition through enhanced protein expression of P4Hα1, both in vivo and in vitro (0.7-3.3-fold change; P<0.05).

CONCLUSIONS

Sevoflurane dose dependently promotes plaque stabilisation and decreases the incidence of plaque disruption in ApoE^-/- mice by increasing collagen deposition and inhibiting inflammation. These mechanisms may contribute to sevoflurane reducing MACCE.

Key genes associated with non-alcoholic fatty liver disease and acute myocardial infarction

Background

With increasing research on non-alcoholic fatty liver (NAFLD) and acute myocardial infarction (AMI), many studies show a tight correlation between NAFLD and AMI, but the underlying pathophysiology is still not clear. This study was performed to identify the potential hub genes and pathways related to these 2 diseases by using the bioinformatics method.

Material/Methods

The Gene Expression Omnibus (GEO) dataset GSE63067 of NAFLD patients and normal controls was downloaded from the GEO database. The GSE60993 and GSE66360 datasets for AMI patients and healthy controls were also obtained. Differentially expressed genes (DEGs) of NAFLD and AMI datasets and the common genes between them were obtained. Further GO and KEGG enrichment analyses for common genes were performed. To define the pathogenesis associated with both NAFLD and AMI, a protein–protein interaction (PPI) network was constructed. Finally, SPSS software was utilized to analyze the diagnostic value of hub genes in the NAFLD and AMI datasets, respectively.

Results

Seventy-eight common genes were obtained in NAFLD and AMI with the threshold of P-value <0.05. Thirty-one GO terms and 10 KEGG pathways were obtained. Also, the top 10 hub genes (TLR2, LILRB2, CXCL1, FPR1, TLR4, TYROBP, MMP9, FCER1G, CLEC4D, and CCR2) were selected with P<0.05.

Conclusions

The results of this study suggest that some novel genes play an important role in the occurrence and progression NAFLD and AMI. More experimental research and clinical trials are needed to verify our results.

Ginkgolide B inhibits hydrogen peroxide‑induced apoptosis and attenuates cytotoxicity via activating the PI3K/Akt/mTOR signaling pathway in H9c2 cells

Ginkgolide B (GB) is a diterpene lactone found in the leaves of the traditional Chinese medicinal plant Ginkgo that has been shown to have various pharmacological effects. However, the anti-apoptotic properties of GB in cardiovascular disease remain poorly understood. The present study aimed to investigate the effect of GB on hydrogen peroxide-induced cell injury in cardiac H9c2 cells, and to further clarify its protective mechanism of action. An in vitro hydrogen peroxide-treated H9c2 cell model was used in order to mimic myocardial ischemia-reperfusion (I/R) injury. Cell viability was assessed by the Cell Counting Kit-8 assay. The induction of apoptosis was determined by flow cytometry and staining was performed using Hoechst 33342. In addition, the effect of GB on the expression levels of apoptosis-associated proteins was evaluated by western blot analysis. The present study demonstrated that GB protected against hydrogen peroxide-induced cytotoxicity and cell apoptosis in H9c2 cardiac cells. GB upregulated the expression level of the anti-apoptotic protein Bcl-2 and downregulated the expression levels of the pro-apoptotic proteins cleaved caspase-3 and Bax in hydrogen peroxide-treated H9c2 cells. The molecular mechanism underlying the anti-apoptotic effects of GB was subsequently detected. GB pretreatment activated the PI3K/Akt/mTOR signaling pathway and caused an increase in the phosphorylation levels of Akt and mTOR in hydrogen peroxide-treated H9c2 cells. These results revealed that GB inhibited hydrogen peroxide-induced apoptosis in H9c2 cells via activation of the PI3K/Akt/mTOR signaling pathway. These findings indicate the potential therapeutic benefits of GB in the treatment of myocardial I/R injury.

Recent advances into the role of pattern recognition receptors in transplantation

Pattern recognition receptors (PRRs) are germline-encoded sensors best characterized for their critical role in host defense. However, there is accumulating evidence that organ transplantation induces the release or display of molecular patterns of cellular injury and death that trigger PRR-mediated inflammatory responses. There are also new insights that indicate PRRs are able to distinguish between self and non-self, suggesting the existence of non-clonal mechanisms of allorecognition. Collectively, these reports have spurred considerable interest into whether PRRs or their ligands can be targeted to promote transplant survival. This review examines the mounting evidence that PRRs play in transplant-mediated inflammation. Given the large number of PRRs, we will focus on members from four families: the complement system, toll-like receptors, the formylated peptide receptor, and scavenger receptors through examining reports of their activity in experimental models of cellular and solid organ transplantation as well as in the clinical setting.

Role of the Extracellular Signal-Regulated Kinase 1/2 Signaling Pathway in Ischemia-Reperfusion Injury

Extracellular signal-regulated kinase 1/2 (ERK_1/2), an important member of the mitogen-activated protein kinase family, is found in many organisms, and it participates in intracellular signal transduction. Various stimuli induce phosphorylation of ERK_1/2 in vivo and in vitro. Phosphorylated ERK_1/2 moves to the nucleus, activates many transcription factors, regulates gene expression, and controls various physiological processes, finally inducing repair processes or cell death. With the aging of the population around the world, the occurrence of ischemia-reperfusion injury (IRI), especially in the brain, heart, kidney, and other important organs, is becoming increasingly serious. Abnormal activation of the ERK_1/2 signaling pathway is closely related to the development and the metabolic mechanisms of IRI. However, the effects of this signaling pathway and the underlying mechanism differ between various models of IRI. This review summarizes the ERK_1/2 signaling pathway and the molecular mechanism underlying its role in models of IRI in the brain, heart, liver, kidneys, and other organs. This information will help to deepen the understanding of ERK_1/2 signals and deepen the exploration of IRI treatment based on the ERK_1/2 study.

Novel Molecular Targets Participating in Myocardial Ischemia-Reperfusion Injury and Cardioprotection

Worldwide morbidity and mortality from acute myocardial infarction (AMI) and related heart failure remain high. While effective early reperfusion of the criminal coronary artery after a confirmed AMI is the typical treatment at present, collateral myocardial ischemia-reperfusion injury (MIRI) and pertinent cardioprotection are still challenging to address and have inadequately understood mechanisms. Therefore, unveiling the related novel molecular targets and networks participating in triggering and resisting the pathobiology of MIRI is a promising and valuable frontier. The present study specifically focuses on the recent MIRI advances that are supported by sophisticated bio-methodology in order to bring the poorly understood interrelationship among pro- and anti-MIRI participant molecules up to date, as well as to identify findings that may facilitate the further investigation of novel targets.

Cardioprotective effects of constitutively active MEK1 against H2O2-induced apoptosis and autophagy in cardiomyocytes via the ERK1/2 signaling pathway

Oxidative stress injury is one of the main mechanisms of ischemia-reperfusion (I/R) injury. The extracellular signal-regulated kinase (ERK1/2) pathway plays an important role in cardioprotective during acute myocardial infarction. In this study, we used constitutively active MEK1 gene (CaMEK) transfection strategy to investigate whether CaMEK provides a protective effect against apoptosis and autophagy induced by Hydrogen peroxide (H₂O₂) in neonatal rat cardiac ventricular cardiomyocytes (NCMs) and the underlying mechanisms. As a result, CaMEK attenuated H₂O₂-induced apoptosis and cytotoxicity in NCMs, evidenced by decreased apoptotic cells and the ratio of Bax/Bcl-2, increased the mitochondrial membrane potential (Δψm) and cell vitality and reduced the level of lactate dehydrogenase (LDH). Further studies revealed that CaMEK attenuated H₂O₂-induced autophagy, evidenced by the decreased LC3-Ⅱ/LC3-Ⅰratio and SQSTM1/p62 (p62) degradation. Furthermore, we demonstrated that CaMEK phosphorylated the ERK1/2 pathway-related proteins, ERK1/2, p70S6K and GSK3β, in NCMs with H₂O₂ stimulation. In contrast, these effects could be reversed by co-treatment with the ERK1/2 inhibitor, PD98059. These results suggest that CaMEK plays an important role in protecting cardiomyocytes against H₂O₂-induced injury and autophagy in NCMs via ERK1/2 pathway. Therefore, transfection of CaMEK may provide a hopeful therapeutic strategy for I/R.