N6-Methyladenosine RNA Methylation in Cardiovascular Diseases

Insights From m6A RNA Methylation: Biomarkers for Diagnosis of Acute Myocardial Infarction

Purpose

Acute myocardial infarction (AMI) is a major contributor to death. The purpose of this study is to explore circulating biomarkers for AMI diagnosis from the perspectives of immunological microenvironment and N6-methyladenosine (m6A) RNA methylation regulation.

Patients and Methods

The GSE59867 dataset was used to download platform and probe data for conducting differential analysis of m6A regulators. A diagnostic nomogram was created utilizing the random-forest method and evaluated for predictive power. m6A-related gene patterns were identified, and their immune microenvironment characteristics were analyzed. Peripheral blood samples were obtained for validation in patient-based investigations using RT-qPCR. The association between m6A regulators and clinical parameters was examined via Spearman correlation analysis.

Results

With a predictive nomogram model developed using key m6A regulators, two distinct m6A subtypes were identified, showing significant variations in infiltrating immunocyte abundance. In confirmation of the model prediction, examination of patient blood identified METTL3, WTAP, RBM15, ALKBH5, FTO, and FMR1 as novel circulating biomarkers for AMI diagnosis. METTL3 and FTO were identified as promising biomarkers for AMI given that they showed a positive correlation with left ventricular ejection fraction.

Conclusion

The study identified six m6A regulators as circulating biomarkers for AMI diagnosis and suggested a potential role for m6A-mediated immune cell infiltration in the pathogenesis of AMI.

N6-methyladenosine (m6A) RNA methylation of LncRNA LINC01214 accelerates the progression of non-small cell lung cancer (NSCLC) by targeting miR-195-5p/ROCK1 axis

Long non-coding RNA LINC01214 is reported to be up-regulated in non-small cell lung cancer (NSCLC), however, its function in NSCLC has not been elucidated yet. In our study, we verified that LINC01214 was aberrantly higher in the tumor tissues and cell lines than that in the normal controls, and was relevant to the severity and prognosis of NSCLC through using real-time quantitative PCR. Then, 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide assay and flow cytometry illustrated that knocking down LINC01214 restrained cell proliferation and promoted apoptosis in A549 and H1299 cells. Additionally, western blot results confirmed that LINC01214 silence reduced the protein expression of CDK2, CDK6, CyclinD1 and Bcl2, but increased the protein expression of Bax and Caspase-3. Of note, compared to normal cells, NSCLC cells had higher enrichment level of N6-methyladenosine (m6A) modification of LINC01214, while reducing m6A modification of LINC01214 weakened the stability of LINC01214 and diminished its level in A549 and H1299 through down-regulating methyltransferase METTL3 or overexpressing demethylase ALKBH5. Subsequently, molecular experiments proved that LINC01214 acted as a sponge for miR-195-5p to elevate ROCK1 expression in NSCLC. Furthermore, data from functional recovery experiments showed that elevating miR-195-5p also exerted tumor-suppressive effects in NSCLC; meanwhile, the effects were reversed by overexpressing ROCK1 or inhibiting miR-195-5p. In short, m6A modification-mediated up-regulation of LINC01214 advances cell proliferation and tumorigenesis to promote NSCLC progression through inhibiting miR-195-5p to up-regulate ROCK1.

Detecting a wide range of epitranscriptomic modifications using a nanopore-sequencing-based computational approach with 1D score-clustering

To date, over 40 epigenetic and 300 epitranscriptomic modifications have been identified. However, current short-read sequencing-based experimental methods can detect <10% of these modifications. Integrating long-read sequencing technologies with advanced computational approaches, including statistical analysis and machine learning, offers a promising new frontier to address this challenge. While supervised machine learning methods have achieved some success, their usefulness is restricted to a limited number of well-characterized modifications. Here, we introduce Modena, an innovative unsupervised learning approach utilizing long-read nanopore sequencing capable of detecting a broad range of modifications. Modena outperformed other methods in five out of six benchmark datasets, in some cases by a wide margin, while being equally competitive with the second best method on one dataset. Uniquely, Modena also demonstrates consistent accuracy on a DNA dataset, distinguishing it from other approaches. A key feature of Modena is its use of 'dynamic thresholding', an approach based on 1D score-clustering. This methodology differs substantially from the traditional statistics-based 'hard-thresholds.' We show that this approach is not limited to Modena but has broader applicability. Specifically, when combined with two existing algorithms, 'dynamic thresholding' significantly enhances their performance, resulting in up to a threefold improvement in F1-scores.

The therapeutic potential of RNA m(6)A in lung cancer

Lung cancer (LC) is a highly malignant and metastatic form of cancer. The global incidence of and mortality from LC is steadily increasing; the mean 5-year overall survival (OS) rate for LC is less than 20%. This frustrating situation may be attributed to the fact that the pathogenesis of LC remains poorly understood and there is still no cure for mid to advanced LC. Methylation at the N6-position of adenosine (N6mA) of RNA (m(6)A) is widely present in human tissues and organs, and has been found to be necessary for cell development and maintenance of homeostasis. However, numerous basic and clinical studies have demonstrated that RNA m(6)A is deregulated in many human malignancies including LC. This can drive LC malignant characteristics such as proliferation, stemness, invasion, epithelial-mesenchymal transition (EMT), metastasis, and therapeutic resistance. Intriguingly, an increasing number of studies have also shown that eliminating RNA m(6)A dysfunction can exert significant anti-cancer effects on LC such as suppression of cell proliferation and viability, induction of cell death, and reversal of treatment insensitivity. The current review comprehensively discusses the therapeutic potential of RNA m(6)A and its underlying molecular mechanisms in LC, providing useful information for the development of novel LC treatment strategies.

m6A-modified circCacna1c regulates necroptosis and ischemic myocardial injury by inhibiting Hnrnpf entry into the nucleus

BACKGROUND

Circular RNAs (circRNAs) are differentially expressed in various cardiovascular diseases, including myocardial infarction (MI) injury. However, their functional role in necroptosis-induced loss of cardiomyocytes remains unclear. We identified a cardiac necroptosis-associated circRNA transcribed from the Cacna1c gene (circCacna1c) to investigate the involvement of circRNAs in cardiomyocyte necroptosis.

METHODS

To investigate the role of circCacna1c during oxidative stress, H9c2 cells and neonatal rat cardiomyocytes were treated with hydrogen peroxide (H2O2) to induce reactive oxygen species (ROS)-induced cardiomyocyte death. The N6-methyladenosine (m6A) modification level of circCacna1c was determined by methylated RNA immunoprecipitation quantitative polymerase chain reaction (MeRIP-qPCR) analysis. Additionally, an RNA pull-down assay was performed to identify interacting proteins of circCacna1c in cardiomyocytes, and the regulatory role of circCacna1c in target protein expression was tested using a western blotting assay. Furthermore, the MI mouse model was constructed to analyze the effect of circCacna1c on heart function and cardiomyocyte necroptosis.

RESULTS

The expression of circCacna1c was found to be reduced in cardiomyocytes exposed to oxidative stress and in mouse hearts injured by MI. Overexpression of circCacna1c inhibited necroptosis of cardiomyocytes induced by hydrogen peroxide and MI injury, resulting in a significant reduction in myocardial infarction size and improved cardiac function. Mechanistically, circCacna1c directly interacts with heterogeneous nuclear ribonucleoprotein F (Hnrnpf) in the cytoplasm, preventing its nuclear translocation and leading to reduced Hnrnpf levels within the nucleus. This subsequently suppresses Hnrnpf-dependent receptor-interacting protein kinase 1 (RIPK1) expression. Furthermore, fat mass and obesity-associated protein (FTO) mediates demethylation of m6A modification on circCacna1c during necrosis and facilitates degradation of circCacna1c.

CONCLUSION

Our study demonstrates that circCacna1c can improve cardiac function following MI-induced heart injury by inhibiting the Hnrnpf/RIPK1-mediated cardiomyocyte necroptosis. Therefore, the FTO/circCacna1c/Hnrnpf/RIPK1 axis holds great potential as an effective target for attenuating cardiac injury caused by necroptosis in ischemic heart disease.

Regulatory roles of N6-methyladenosine (m6A) methylation in RNA processing and non-communicable diseases

Post-transcriptional RNA modification is an emerging epigenetic control mechanism in cells that is important in many different cellular and organismal processes. N6-methyladenosine (m6A) is one of the most prevalent, prolific, and ubiquitous internal transcriptional alterations in eukaryotic mRNAs, making it an important topic in the field of Epigenetics. m6A methylation acts as a dynamical regulatory process that regulates the activity of genes and participates in multiple physiological processes, by supporting multiple aspects of essential mRNA metabolic processes, including pre-mRNA splicing, nuclear export, translation, miRNA synthesis, and stability. Extensive research has linked aberrations in m6A modification and m6A-associated proteins to a wide range of human diseases. However, the impact of m6A on mRNA metabolism and its pathological connection between m6A and other non-communicable diseases, including cardiovascular disease, neurodegenerative disorders, liver diseases, and cancer remains in fragmentation. Here, we review the existing understanding of the overall role of mechanisms by which m6A exerts its activities and address new discoveries that highlight m6A's diverse involvement in gene expression regulation. We discuss m6A deposition on mRNA and its consequences on degradation, translation, and transcription, as well as m6A methylation of non-coding chromosomal-associated RNA species. This study could give new information about the molecular process, early detection, tailored treatment, and predictive evaluation of human non-communicable diseases like cancer. We also explore more about new data that suggests targeting m6A regulators in diseases may have therapeutic advantages.

Clinical significance of the m6A methyltransferase METTL3 in peripheral blood of patients with coronary heart disease

Objective

This study aims to explore the association of methyltransferase-like protein 3 (METTL3) expression with severity of coronary artery stenosis in patients with coronary heart disease (CHD).

Methods

A total of 100 patients administrated in the Fourth Affiliated Hospital of China Medical University between October 2022 and June 2023 with primary symptoms of chest pain or tightness, or cardiac discomfort, and who underwent coronary angiography for a definitive diagnosis, were included in the study. The baseline characteristics, including TG, TC, LDL-C, HDL-C, uric acid and past history were recorded. Peripheral blood samples were collected to assess the expression levels of METTL3, YT521-B homology domains 1 (YTHDF1), YT521-B homology domains 2 (YTHDF2), and YT521-B homology domains 3 (YTHDF3) using the PCR method. Relative expression levels of METTL3 protein were determined by Western blotting. Correlation analysis were conducted to evaluate the relationship between METTL3/YTHDF1 gene expression and clinical data. Receiver operating characteristic (ROC) curve analysis was employed to assess the predictive value of METTL3 and YTHDF1 for CHD. Binary logistic regression was used to determine whether the expression of METTL3 and YTHDF1 in peripheral blood were risk factors for CHD.

Results

The study found no significant differences in baseline characteristics between CHD patients and controls, except for length of stay, Lymphocytes, Neutrophils, AST, HDL-C and modified Gensini score. The gene expression levels of METTL3 and YTHDF1 were significantly higher in CHD patients compared to controls (p < 0.05). Furthermore, METTL3 protein expression was also significantly elevated in the CHD group compared to the control group (p < 0.05). METTL3 gene expression correlated with HDL-C and Gensini score, while YTHDF1 gene expression correlated with Age, WBC, Neutrophils, RDW-CV, modified Gensini score. ROC curve analysis demonstrated an AUC of 0.692 for METTL3 in CHD, with a sensitivity of 66.7% and a specificity of 69.8% at a cut-off value of >0.052. The AUC for YTHDF1 in CHD was 0.623, with a sensitivity of 47.4% and a specificity of 74.4% at a cut-off value of >0.027. Binary logistic regression revealed that only increased METTL3 expression in peripheral blood was an independent risk factor for CHD (p < 0.05).

Conclusions

The increased expression of METTL3 in peripheral blood may serve as a potential biomarker and predictive factor for CHD.

Role of m6A RNA Methylation in Ischemic Stroke

Ischemic stroke is a prominent contributor to global morbidity and mortality rates. The intricate and diverse mechanisms underlying ischemia-reperfusion injury remain poorly comprehended. RNA methylation, an emerging epigenetic modification, plays a crucial role in regulating numerous biological processes, including immunity, DNA damage response, tumorigenesis, metastasis, stem cell renewal, adipocyte differentiation, circadian rhythms, cellular development and differentiation, and cell division. Among the various RNA modifications, N6-methyladenosine (m6A) modification stands as the most prevalent in mammalian mRNA. Recent studies have demonstrated the crucial involvement of m6A modification in the pathophysiological progression of ischemic stroke. This review aims to elucidate the advancements in ischemic stroke-specific investigations pertaining to m6A modification, consolidate the underlying mechanisms implicated in the participation of m6A modification during the onset of ischemic stroke, and deliberate on the potential of m6A modification as a viable therapeutic target for ischemic stroke.

N6-Methyladenosine in Vascular Aging and Related Diseases: Clinical Perspectives

Aging leads to progressive deterioration of the structure and function of arteries, which eventually contributes to the development of vascular aging-related diseases. N6-methyladenosine (m6A) is the most prevalent modification in eukaryotic RNAs. This reversible m6A RNA modification is dynamically regulated by writers, erasers, and readers, playing a critical role in various physiological and pathological conditions by affecting almost all stages of the RNA life cycle. Recent studies have highlighted the involvement of m6A in vascular aging and related diseases, shedding light on its potential clinical significance. In this paper, we comprehensively discuss the current understanding of m6A in vascular aging and its clinical implications. We discuss the molecular insights into m6A and its association with clinical realities, emphasizing its significance in unraveling the mechanisms underlying vascular aging. Furthermore, we explore the possibility of m6A and its regulators as clinical indicators for early diagnosis and prognosis prediction and investigate the therapeutic potential of m6A-associated anti-aging approaches. We also examine the challenges and future directions in this field and highlight the necessity of integrating m6A knowledge into patient-centered care. Finally, we emphasize the need for multidisciplinary collaboration to advance the field of m6A research and its clinical application.

N6-Methyladenosine Methylation of mRNA in Cell Apoptosis

Apoptosis, a highly controlled homeostatic mechanism that eliminates single cells without destroying tissue function, occurs during growing development and senescence. N6-methyladenosine (m6A), as the most common internal modification of eukaryotic mRNA, fine-tunes gene expression by regulating many aspects of mRNA metabolism, such as splicing, nucleation, stability, translation, and degradation. Remarkably, recent reports have indicated that aberrant methylation of m6A-related RNA may directly or indirectly influence the expression of apoptosis-related genes, thus regulating the process of cell apoptosis. In this review, we summarized the relationship between m6A modification and cell apoptosis, especially its role in the nervous system, and analyzed the limitations of the current research.

RNA methylation: A potential therapeutic target in autoimmune disease

Autoimmune diseases such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and inflammatory bowel disease (IBD) are caused by the body's immune response to autoantigens. The pathogenesis of autoimmune diseases is unclear. Numerous studies have demonstrated that RNA methylation plays a key role in disease progression, which is essential for post-transcriptional regulation and has gradually become a broad regulatory mechanism that controls gene expression in various physiological processes, including RNA nuclear output, translation, splicing, and noncoding RNA processing. Here, we outline the writers, erasers, and readers of RNA methylation, including N6-methyladenosine (m6A), 2'-O-methylation (Nm), 2'-O-dimethyladenosine (m6Am), N1-methyladenosine (m1A), 5-methylcytidine (m5C) and N7-methylguanosine (m7G). As the role of RNA methylation modifications in the immune system and diseases is explained, the potential treatment value of these modifications has also been demonstrated. This review reports the relationship between RNA methylation and autoimmune diseases, highlighting the need for future research into the therapeutic potential of RNA modifications.

M6A-related bioinformatics analysis indicates that LRPPRC is an immune marker for ischemic stroke

Ischemic stroke (IS) is a common cerebrovascular disease whose pathogenesis involves a variety of immune molecules, immune channels and immune processes. 6-methyladenosine (m6A) modification regulates a variety of immune metabolic and immunopathological processes, but the role of m6A in IS is not yet understood. We downloaded the data set GSE58294 from the GEO database and screened for m6A-regulated differential expression genes. The RF algorithm was selected to screen the m6A key regulatory genes. Clinical prediction models were constructed and validated based on m6A key regulatory genes. IS patients were grouped according to the expression of m6A key regulatory genes, and immune markers of IS were identified based on immune infiltration characteristics and correlation. Finally, we performed functional enrichment, protein interaction network analysis and molecular prediction of the immune biomarkers. We identified a total of 7 differentially expressed genes in the dataset, namely METTL3, WTAP, YWHAG, TRA2A, YTHDF3, LRPPRC and HNRNPA2B1. The random forest algorithm indicated that all 7 genes were m6A key regulatory genes of IS, and the credibility of the above key regulatory genes was verified by constructing a clinical prediction model. Based on the expression of key regulatory genes, we divided IS patients into 2 groups. Based on the expression of the gene LRPPRC and the correlation of immune infiltration under different subgroups, LRPPRC was identified as an immune biomarker for IS. GO enrichment analyses indicate that LRPPRC is associated with a variety of cellular functions. Protein interaction network analysis and molecular prediction indicated that LRPPRC correlates with a variety of immune proteins, and LRPPRC may serve as a target for IS drug therapy. Our findings suggest that LRPPRC is an immune marker for IS. Further analysis based on LRPPRC could elucidate its role in the immune microenvironment of IS.

RNA modification m6Am: the role in cardiac biology

Epitranscriptomic modifications have recently emerged into the spotlight of researchers due to their vast regulatory effects on gene expression and thereby cellular physiology and pathophysiology. N⁶,2'-O-dimethyladenosine (m⁶Am) is one of the most prevalent chemical marks on RNA and is dynamically regulated by writers (PCIF1, METTL4) and erasers (FTO). The presence or absence of m⁶Am in RNA affects mRNA stability, regulates transcription, and modulates pre-mRNA splicing. Nevertheless, its functions in the heart are poorly known. This review summarizes the current knowledge and gaps about m⁶Am modification and its regulators in cardiac biology. It also points out technical challenges and lists the currently available techniques to measure m⁶Am. A better understanding of epitranscriptomic modifications is needed to improve our knowledge of the molecular regulations in the heart which may lead to novel cardioprotective strategies.

RNA methylation reading protein YTHDF2 relieves myocardial ischemia-reperfusion injury by downregulating BNIP3 via m6A modification

BNIP3 is reported to be involved in hypoxia-induced mitochondrial defect and cell death in cardiomyocytes. However, little is known about the specific function and molecular mechanism of BNIP3-mediated mitophagy in myocardial ischemia-reperfusion injury (MIRI). Herein, this study explored the mechanism regulating BNIP3-modulated mitophagy in MIRI. Rat cardiomyocytes (H9c2 cells) underwent transfection and hypoxia/reoxygenation (H/R) treatment, followed by cell viability and apoptosis detection. Gain-of-function assays were conducted in rats before MIRI modeling, followed by the monitoring of cardiac changes and the evaluation of cardiac function, myocardial infarction area, and apoptosis in myocardial tissues. The levels of creatine kinase MB (CK-MB), cardiac troponin I (cTnI), lactic dehydrogenase (LDH), reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), p62, and LC3 II/LC3 I were tested in rat serum or H9c2 cells. The co-localization of LC3 and TOMM20 was analyzed. The interaction of BNIP3 with YTHDF2 was assessed. H/R treatment decreased cell viability and p62 and SOD levels while elevating cell apoptosis, the levels of CK-MB, cTnI, LDH, MDA, ROS, and LC3 II/LC3 I, the number of autophagosomes, and the co-localization of LC3 and TOMM20 in cardiomyocytes, which were neutralized by downregulating BNIP3 or upregulating YTHDF2. Moreover, upregulation of YTHDF2 repressed myocardial injury and mitophagy in MIRI rats. Mechanistically, YTHDF2 mediated BNIP3 expression by recognizing methylated BNIP3. Upregulation of BNIP3 counteracted the suppressive effect of YTHDF2 overexpression on H/R-induced injury and mitophagy in cardiomyocytes. The RNA methylation reading protein YTHDF2 ameliorated MIRI by downregulating BNIP3 via m6A modification.

Klf6 aggravates myocardial ischemia/reperfusion injury by activating Acsl4-mediated ferroptosis

Ferroptosis is closely related to myocardial ischemia/reperfusion (I/R) damage. Kruppel-like factor 6 (Klf6) can aggravate renal I/R injury. We aimed to elucidate the role of Klf6 in myocardial I/R damage as well as its potential mechanism. Myocardial I/R mice model and hypoxia/reoxygenation (H/R)-treated HL-1 cells were established. The levels of Fe2+ , MDA, lipid ROS, and ferroptosis-related proteins were measured for assessing ferroptosis. Infarct area, H&E staining, cardiac function, and cell viability were detected for evaluating myocardial injury. Immunohistochemistry, immunofluorescence, western blot, and RT-qPCR were applied for detecting the levels of related genes. The m6A modification of Klf6, as well as the relationships between Klf6 and Mettl3, Igf2bp2, or Acsl4 promoter, was evaluated using MeRIP, RNA immunoprecipitation, RNA pull-down, chromatin immunoprecipitation, and luciferase reporter assay accordingly.Klf6 protein and mRNA levels, as well as Klf6 m6A modification, were elevated in HL-1 cells subjected to H/R and in the heart tissues from I/R mice. In H/R-challenged HL-1 cells, the binding relationships between Klf6 mRNA and Igf2bp2 or Mettl3 were confirmed; moreover, Igf2bp2 or Mettl3 knockdown decreased the Klf6 level and inhibited Klf6 mRNA stability. Klf6 knockdown restrained H/R-triggered cell viability loss, improved I/R-induced myocardial injury, and inhibited ferroptosis in myocardial I/R damage models. Klf6 directly bound to the Acsl4 promoter and positively regulated its expression. Acsl4 overexpression compromised the Klf6 knockdown-generated protective effect in HL-1 cells.m6A modification-regulated Klf6 aggravated myocardial I/R damage through activating Acsl4-mediated ferroptosis, thereby providing one potential target for the treatment of myocardial I/R.

RNA-Binding Proteins as Critical Post-Transcriptional Regulators of Cardiac Regeneration

Myocardial injury causes death to cardiomyocytes and leads to heart failure. The adult mammalian heart has very limited regenerative capacity. However, the heart from early postnatal mammals and from adult lower vertebrates can fully regenerate after apical resection or myocardial infarction. Thus, it is of particular interest to decipher the mechanism underlying cardiac regeneration that preserves heart structure and function. RNA-binding proteins, as key regulators of post-transcriptional gene expression to coordinate cell differentiation and maintain tissue homeostasis, display dynamic expression in fetal and adult hearts. Accumulating evidence has demonstrated their importance for the survival and proliferation of cardiomyocytes following neonatal and postnatal cardiac injury. Functional studies suggest that RNA-binding proteins relay damage-stimulated cell extrinsic or intrinsic signals to regulate heart regenerative capacity by reprogramming multiple molecular and cellular processes, such as global protein synthesis, metabolic changes, hypertrophic growth, and cellular plasticity. Since manipulating the activity of RNA-binding proteins can improve the formation of new cardiomyocytes and extend the window of the cardiac regenerative capacity in mammals, they are potential targets of therapeutic interventions for cardiovascular disease. This review discusses our evolving understanding of RNA-binding proteins in regulating cardiac repair and regeneration, with the aim to identify important open questions that merit further investigations.

The Nine RNA Methylation Regulatory Gene Signature Is Associated with the Pathogenesis of Atrial Fibrillation by Modulating the Immune Microenvironment in the Atrial Tissues

Background. Atrial fibrillation (AF) is the most common type of cardiac arrhythmias and a major cause of cardiovascular disease (CVD)-related deaths globally. RNA methylation is the most frequent posttranscriptional modification in the eukaryotic RNAs. Previous studies have demonstrated close associations between the status of RNA methylation and CVD. Methods. We comprehensively evaluated the relationship between RNA methylation and AF. Least absolute shrinkage and selection operator (LASSO) logistic regression analysis was used to establish a risk score model in AF. Biological functional analysis was used to explore the relationship between RNA methylation related signatures and immune microenvironment characteristics. Machine learning was used to recognize the outstanding RNA methylation regulators in AF. Results. There was a significant variant of the mRNA expression of RNA methylation regulators in AF. RNA methylation related risk score could predict the onset of AF and closely associated with immune microenvironment features. XG-Boost algorithm and SHAP recognized that NSUN3 and DCPS might play a key role in the development of AF. Meanwhile, NSUN3 and DCPS had potential diagnostic value in AF. Conclusion. RNA methylation regulatory genes are associated with the onset of AF by modulating the immune microenvironment. The nine AF risk-related RNA methylation regulatory gene signature is a potential diagnostic biomarker and therapeutic target for AF.

m6A eraser ALKBH5 mitigates the apoptosis of cardiomyocytes in ischemia reperfusion injury through m6A/SIRT1 axis

Recent studies have shown that the potential regulatory role of N⁶-methyladenine (m⁶A) modification may affect the occurrence and development of various cardiovascular diseases. However, the regulatory mechanism of m⁶A modification on myocardial ischemia reperfusion injury (MIRI) is rarely reported. A mouse model of myocardial ischemia reperfusion (I/R) was established by ligation and perfusion of the left anterior descending coronary artery, and a cellular model of hypoxia/reperfusion (H/R) was conducted in cardiomyocytes (CMs). We found that the protein expression of ALKBH5 in myocardial tissues and cells were decreased, accompanied by increased m⁶A modification level. Overexpression of ALKBH5 significantly inhibited H/R-induced oxidative stress and apoptosis in CMs. Mechanistically, there was an enriched m⁶A motif in the 3'-UTR of SIRT1 genome, and ALKBH5 overexpression promoted the stability of SIRT1 mRNA. Furthermore, results using overexpression or knockdown of SIRT1 confirmed the protective effect of SIRT1 on H/R induced CMs apoptosis. Together, our study reveals a critical role of ALKBH5-medicated m⁶A on CM apoptosis, supplying an important regulating effect of m⁶A methylation in ischemic heart disease.

An overview of the effects and mechanisms of m6 A methylation on innate immune cells in sepsis

Introduction

Sepsis is a severe clinical syndrome caused by dysregulated systemic inflammatory responses to infection. Methylation modification, as a crucial mechanism of RNA functional modification, can manipulate the immunophenotype and functional activity of immune cells to participate in sepsis progression. This study aims to explore the mechanism of N6-methyladenosine (m6A) methylation modification in immune cell-mediated sepsis through keyword search.

Methods

Literature retrieval.

Results and Discussion

Literature retrieval reveals that m6A methylation is implicated in sepsis-induced lung injury and myocardial injury,as well as sepsis-related encephalopathy. Furthermore, it is found that m6A methylation can regulate sepsis by inhibiting the chemotaxis of neutrophils and the formation of neutrophil extracellular traps and suppressing macrophage phagocytosis, thereby playing a role in sepsis.

Identification of GLS as a cuproptosis-related diagnosis gene in acute myocardial infarction

Acute myocardial infarction (AMI) has the characteristics of sudden onset, rapid progression, poor prognosis, and so on. Therefore, it is urgent to identify diagnostic and prognostic biomarkers for it. Cuproptosis is a new form of mitochondrial respiratory-dependent cell death. However, studies are limited on the clinical significance of cuproptosis-related genes (CRGs) in AMI. In this study, we systematically assessed the genetic alterations of CRGs in AMI by bioinformatics approach. The results showed that six CRGs (LIAS, LIPT1, DLAT, PDHB, MTF1, and GLS) were markedly differentially expressed between stable coronary heart disease (stable_CAD) and AMI. Correlation analysis indicated that CRGs were closely correlated with N6-methyladenosine (m6A)-related genes through R language "corrplot" package, especially GLS was positively correlated with FMR1 and MTF1 was negatively correlated with HNRNPA2B1. Immune landscape analysis results revealed that CRGs were closely related to various immune cells, especially GLS was positively correlated with T cells CD4 memory resting and negatively correlated with monocytes. Kaplan-Meier analysis demonstrated that the group with high DLAT expression had a better prognosis. The area under curve (AUC) certified that GLS had good diagnostic value, in the training set (AUC = 0.87) and verification set (ACU = 0.99). Gene set enrichment analysis (GSEA) suggested that GLS was associated with immune- and hypoxia-related pathways. In addition, Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, competing endogenous RNA (ceRNA) analysis, transcription factor (TF), and compound prediction were performed to reveal the regulatory mechanism of CRGs in AMI. Overall, our study can provide additional information for understanding the role of CRGs in AMI, which may provide new insights into the identification of therapeutic targets for AMI.

Silencing of YTHDF1 Attenuates Cerebral Stroke by Inducing PTEN Degradation and Activating the PTEN/AKT/mTOR Pathway

N6-methyladenosine (m6A) methylation regulates pathological processes of cerebral stroke, which can lead to disability and death. Herein, we explored the role of a m6A "reader" YTHDF1 in stroke. MCAO (middle cerebral artery occlusion) rat model and hypoxia/reoxygenation (H/R)-induced neurocytes cell model were established. TTC staining assay assessed the infarction area and TUNEL assay analyzed apoptosis. Neurological score was analyzed to evaluate the brain function. Cell counting kit-8, LDH release, and flow cytometry assessed cellular proliferation, cell death, and cell apoptosis in vitro. The expression of YTHDF1, PTEN, and the factors in the PI3K/AKT/mTOR pathway was measured using western blot. The interaction between YTHDF1 and PTEN was confirmed luciferase assay and RNA immunoprecipitation assay. The results indicated that YTHDF1 was upregulated in the brain tissues of MCAO mice and H/R-treated cells. Knockdown of YTHDF1 inhibited the infarct area, neuron damage, and apoptosis. Additionally, YTHDF1 depletion promoted viability and inhibited apoptosis of H/R-treated cells. Moreover, YTHDF1 inactivated the PI3K/AKT/mTOR pathway. Mechanistically, YTHDF1 binds to PTEN to increase PTEN mRNA stability. Overexpressing PTEN rescued the effects of YTHDF1 depletion on cell viability and apoptosis. In conclusion, silencing of YTHDF1 decelerated the progression of cerebral stroke through promoting PTEN degradation and activating the PTEN/AKT/mTOR pathway, suggesting that YTHDF1 has the potential to be a therapeutic target for stroke.

Targeting Epigenetic Regulation of Cardiomyocytes through Development for Therapeutic Cardiac Regeneration after Heart Failure

Cardiovascular diseases are the leading cause of death globally, with no cure currently. Therefore, there is a dire need to further understand the mechanisms that arise during heart failure. Notoriously, the adult mammalian heart has a very limited ability to regenerate its functional cardiac cells, cardiomyocytes, after injury. However, the neonatal mammalian heart has a window of regeneration that allows for the repair and renewal of cardiomyocytes after injury. This specific timeline has been of interest in the field of cardiovascular and regenerative biology as a potential target for adult cardiomyocyte repair. Recently, many of the neonatal cardiomyocyte regeneration mechanisms have been associated with epigenetic regulation within the heart. This review summarizes the current and most promising epigenetic mechanisms in neonatal cardiomyocyte regeneration, with a specific emphasis on the potential for targeting these mechanisms in adult cardiac models for repair after injury.

Crosstalk among N6-methyladenosine modification and RNAs in central nervous system injuries

Central nervous system (CNS) injuries, including traumatic brain injury (TBI), intracerebral hemorrhage (ICH) and ischemic stroke, are the most common cause of death and disability around the world. As the most common modification on ribonucleic acids (RNAs), N6-methyladenosine (m6A) modification has recently attracted great attentions due to its functions in determining the fate of RNAs through changes in splicing, translation, degradation and stability. A large number of studies have suggested that m6A modification played an important role in brain development and involved in many neurological disorders, particularly in CNS injuries. It has been proposed that m6A modification could improve neurological impairment, inhibit apoptosis, suppress inflammation, reduce pyroptosis and attenuate ferroptosis in CNS injuries via different molecules including phosphatase and tensin homolog (PTEN), NLR family pyrin domain containing 3 (NLRP3), B-cell lymphoma 2 (Bcl-2), glutathione peroxidase 4 (GPX4), and long non-coding RNA (lncRNA). Therefore, m6A modification showed great promise as potential targets in CNS injuries. In this article, we present a review highlighting the role of m6A modification in CNS injuries. Hence, on the basis of these properties and effects, m6A modification may be developed as therapeutic agents for CNS injury patients.