Role of N6-methyladenosine Modification in Cardiac Remodeling

Comprehensive Analysis of RNA Modifications Related Genes in the Diagnosis and Subtype Classification of Dilated Cardiomyopathy

Background

RNA modifications are associated to various human diseases. However, the functions of RNA modification-related genes have yet to be thoroughly investigated in dilated cardiomyopathy (DCM). This study sought to conduct a comprehensive analysis of RNA modification-associated genes for the diagnosis and subtype classification of DCM.

Methods

We collected DCM and control sample RNA modification-related genes from Gene Expression Omnibus (GEO) microarray datasets. Differential expression analysis was performed on these using the "Limma" package in R. Univariate logistic regression, and the LASSO algorithm were used to identify optimal genes for diagnostic model establishment. Furthermore, ConsensusClusterPlus was used to identify RNA modification-molecular subtypes. Lastly, the expression of the hub RNA modification-related genes and their connection to DCM were confirmed using the clinical samples and mouse models.

Results

Twenty-six RNA modification-related genes were identified as dysregulated in DCM, with strong connections noted among these genes. A diagnostic model based on 13 genes (TRMT61B, MBD2, YTHDC2, NOP2, TRMT10C, WDR4, CPSF2, CSTF3, ZBTB4, UNG, NSUN6, TET1, and DNMT3B) with an AUC of 0.980 predicted DCM well. Infiltrating plasma B cells, eosinophils, CD8 T cells, and regulatory T cells correlated strongly with TRMT61B, MBD2, YTHDC2, and CPSF2. Two RNA modification-molecular subtypes (clusters 1 and 2) were identified. Cluster 1 had greater RNA modification scores, lower immune ratings, and lower HLA-DRB1 and HLA-DPB1 expression than Cluster 2. Cluster 2 engaged metabolism-related pathways, while Cluster 1 activated renin-angiotensin system pathways.We further found a substantial link between lower cardiac function and up-regulation of TET1, DNMT3B, and down-regulation of MBD2, TRMT61B in the 13 hub RNA modification-related genes.

Conclusion

In conclusion, our RNA modification-related diagnostic model predicts DCM well. The discovery of two RNA modification-molecular subgroups and four key pivotal genes may assist stratify DCM patients by risk.

Aerobic exercise training attenuates ischemia-reperfusion injury in mice by decreasing the methylation level of METTL3-associated m6A RNA in cardiomyocytes

BACKGROUND AND AIMS

Ischemic heart disease (IHD) presents a significant global health challenge, with myocardial ischemia-reperfusion injury (MIRI) being a major pathophysiological contributor and lacking effective interventions. While aerobic exercise training (AET) enhances cardiovascular health, its protective mechanism in MIRI remains elusive. This study aims to elucidate the protective effect of AET in MIRI and its underlying mechanism.

METHODS

A mouse model of AET and MIRI was established to evaluate basic indices, cardiac ultrasound, and myocardial injury markers. Dot Blot, qRT-PCR, and Western blot were employed to assess m6A RNA methylation levels and related protein expression in myocardial tissue. In vitro, primary cardiomyocyte culture was utilized to mimic MIRI, evaluating cell viability, mitochondrial membrane potential, etc. Finally, myocardial tissues of MIRI mice were immunoprecipitated for m6A RNA methylation and sequenced to analyze related signaling pathways.

KEY RESULTS

AET significantly improved cardiac function and mitigated myocardial injury and fibrosis. Moreover, AET protected myocardium from MIRI by reducing m6A RNA methylation levels and modulating METTL3 expression. In vitro experiments demonstrated that the decrease in m6A RNA methylation levels and METTL3 expression conferred resistance to hypoxia/reoxygenation-induced injury. Furthermore, sequencing results indicated elevated myocardial tissue m6A RNA methylation levels during MIRI, activation of the Nrf2-related signaling pathway, and AET-mediated regulation of the Nrf2/HO-1 signaling pathway, thereby attenuating MIRI through modulation of METTL3-related m6A methylation.

CONCLUSION AND SIGNIFICANCE

AET attenuates MIRI by reducing the level of METTL3-related m6A RNA methylation in cardiomyocytes and activating the Nrf2/HO-1 antioxidant signaling pathway. This finding provides a novel insight and strategy for the prevention and treatment of IHD, holding significant clinical implications.

Epigenetic Mechanisms in Osteoporosis: Exploring the Power of m6A RNA Modification

Osteoporosis, recognised as a metabolic disorder, has emerged as a significant burden on global health. Although available treatments have made considerable advancements, they remain inadequately addressed. In recent years, the role of epigenetic mechanisms in skeletal disorders has garnered substantial attention, particularly concerning m6A RNA modification. m6A is the most prevalent dynamic and reversible modification in eukaryotes, mediating various metabolic processes of mRNAs, including splicing, structural conversion, translation, translocation and degradation and serves as a crucial component of epigenetic modification. Research has increasingly validated that m6A plays a vital role in the proliferation, differentiation, migration, invasion,and repair of bone marrow mesenchymal stem cells (BMSCs), osteoblasts and osteoclasts, all of which impact the whole process of osteoporosis pathogenesis. Continuous efforts have been made to target m6A regulators and natural products derived from traditional medicine, which exhibit multiple biological activities such as anti-inflammatory and anticancer effects, have emerged as a valuable resources for m6A drug discovery. This paper elaborates on m6A methylation and its regulatory role in osteoporosis, emphasising its implications for diagnosis and treatment, thereby providing theoretical references.

RBM15 Protects From Myocardial Infarction by Stabilizing NAE1

RNA-binding proteins play multiple roles in several biological processes. However, the roles of RBM15-an important RNA-binding protein and a significant regulator of RNA methylation-in cardiovascular diseases remain elusive. This study aimed to investigate the biological function of RBM15 and its fundamental mechanisms in myocardial infarction (MI). Methylated RNA immunoprecipitation sequencing was used to explore the N6-methyladenosine (m6A) difference between MI and normal tissues. Our findings showed the elevated level of m6A in MI, and its transcription profile in both MI and normal tissues. RBM15 was the main regulator and its overexpression attenuated apoptosis in cardiomyocytes and improved cardiac function in mice after MI. Then, we used one target NEDD8 activating enzyme E1 subunit and its inhibitor (MLN4924) to investigate the impact of RBM15 targets on cardiomyocytes. Finally, the enhanced m6A methylation in the presence of RBM15 overexpression led to the increased expression and stability of NEDD8 activating enzyme E1 subunit. Our findings suggest that the enhanced m6A level is a protective mechanism in MI, and RBM15 is significantly upregulated in MI and promotes cardiac function. This study showed that RBM15 affected MI by stabilizing its target on the cell apoptosis function, which might provide a new insight into MI therapy.

An Emerging Role of Micro- and Nanoplastics in Vascular Diseases

Vascular diseases are the leading causes of death worldwide, and they are attributable to multiple pathologies, such as atherosclerosis, diabetes, and chronic obstructive pulmonary disease. Exposure to various environmental contaminants is associated with the development of various diseases, including vascular diseases. Among environmental contaminants, micro- and nanoplastics have gained attention as global environmental risk factors that threaten human health. Recently, extensive research has been conducted on the effects of micro- and nanoplastics on various human diseases, including vascular diseases. In this review, we highlight the effects of micro- and nanoplastics on vascular diseases.

RUNX1 facilitates heart failure progression through regulating TGF-β-induced cardiac remodeling

Background

Heart failure is caused by acute or chronic cardiovascular diseases with limited treatments and unclear pathogenesis. Therefore, it is urgent to explore new therapeutic targets and reveal new pathogenesis for heart failure.

Methods

We carried out heart failure animal model by transverse aortic arch constriction (TAC) in mice. The left ventricular internal diameter diastole (LVIDd), left ventricular internal diameter systole (LVIDs), and ejection fraction (EF) value were detected using ultrasound and myocardial fibrosis was evaluated by Masson stain assay. Cell apoptosis in myocardial tissues were detected by TUNEL immunofluorescence stain. Signal pathway analysis was performed by dual-luciferase reporter assay and western blot.

Results

Our results showed that inhibition of RUNX1 led to remission of cardiac enlargement induced by TAC in mice. Inhibition of RUNX1 also caused raise of EF and FS value under TAC-induced condition. Besides, RUNX1 inhibition mice showed decreased myocardial fibrosis area under TAC-induced condition. RUNX1 inhibition caused decrease of apoptotic cell rate in myocardial tissues under TAC. Interestingly, we found that RUNX1 could promote the activation of TGF-β/Smads in dual-luciferase reporter assay.

Interpretation

We illustrated that RUNX1 could be considered as a new regulator of myocardial remodeling by activating TGF-β/Smads signaling. Based on this, we concluded that RUNX1 may be developed as a new therapeutic target against heart failure in the future. In addition, this study also provide a new insight for the etiological study on heart failure.

N6-methyladenosine methylation mediates non-coding RNAs modification in microplastic-induced cardiac injury

Owing to their potential adverse health effects, global contamination by microplastics (MPs) has attracted increased scientific and societal concerns. However, in vivo studies on MP toxicity, along with its effects and underlying mechanisms, remain limited. We recently found that non-coding RNA (ncRNAs) contribute to MP-mediated vascular toxicity. Moreover, previous studies have identified N6-methyladenosine (m6A) modifications in ncRNAs as influencing factors in cardiovascular disease. However, whether and how m6A modifications in ncRNAs are affected by MP-induced cardiotoxicity remain unknown. Herein, we profiled differentially expressed ncRNAs and their related m6A modification profiles in MP-exposed myocardial tissue using RNA sequencing (RNA-seq) and methylated RNA immunoprecipitation sequencing (MeRIP-seq). First, we observed that MPs accumulated in different organs and upregulated apoptosis in the heart, liver, spleen, and kidney cells. Furthermore, total m6A and METTL3 levels increased in the myocardium after exposure to MPs. RNA-seq results revealed that 392 lncRNAs and 302 circRNAs were differentially expressed in MP-treated mouse myocardium compared to the control group. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses showed that these altered lncRNAs and circRNAs were closely associated with endocytosis, cellular senescence, and cell cycle signaling pathways, which may cause cardiotoxicity. Furthermore, MeRIP-seq data showed different distributions and abundances of m6A modifications in lncRNAs and circRNAs. Additionally, we identified differentially m6A methylated lncRNAs and circRNAs through conjoint analysis of the two high-throughput sequencing datasets and found that both m6A modifications and the expression of circ-Arfgef2 and lncG3bp2 were upregulated after exposure to MPs. This suggests that MP-induced m6A modifications in ncRNAs are involved in cardiotoxicity. Our findings contribute to a better understanding of MP-induced cardiotoxicity and new molecular targets for treating cardiac injury.

RNA-binding proteins in vascular inflammation and atherosclerosis

Atherosclerotic cardiovascular disease (ASCVD) remains the major cause of premature death and disability worldwide, even when patients with an established manifestation of atherosclerotic heart disease are optimally treated according to the clinical guidelines. Apart from the epigenetic control of transcription of the genetic information to messenger RNAs (mRNAs), gene expression is tightly controlled at the post-transcriptional level before the initiation of translation. Although mRNAs are traditionally perceived as the messenger molecules that bring genetic information from the nuclear DNA to the cytoplasmic ribosomes for protein synthesis, emerging evidence suggests that processes controlling RNA metabolism, driven by RNA-binding proteins (RBPs), affect cellular function in health and disease. Over the recent years, vascular endothelial cell, smooth muscle cell and immune cell RBPs have emerged as key co- or post-transcriptional regulators of several genes related to vascular inflammation and atherosclerosis. In this review, we provide an overview of cell-specific function of RNA-binding proteins involved in all stages of ASCVD and how this knowledge may be used for the development of novel precision medicine therapeutics.

Defining cardiac fibrosis complexity and regulation towards therapeutic development

Cardiac fibrosis is insidious, accelerating cardiovascular diseases, heart failure, and death. With a notable lack of effective therapies, advances in both understanding and targeted treatment of fibrosis are urgently needed. Remodelling of the extracellular matrix alters the biomechanical and biochemical cardiac structure and function, disrupting cell‐matrix interactions and exacerbating pathogenesis to ultimately impair cardiac function. Attempts at clinical fibrotic reduction have been fruitless, constrained by an understanding which severely underestimates its dynamic complexity and regulation. Integration of single‐cell sequencing and quantitative proteomics has provided new insights into cardiac fibrosis, including reparative or maladaptive processes, spatiotemporal changes and fibroblast heterogeneity. Further studies have revealed microenvironmental and intercellular signalling mechanisms (including soluble mediators and extracellular vesicles), and intracellular regulators including post‐translational/epigenetic modifications, RNA binding proteins, and non‐coding RNAs. This understanding of novel disease processes and molecular targets has supported the development of innovative therapeutic strategies. Indeed, targeted modulation of cellular heterogeneity, microenvironmental signalling, and intracellular regulation offer promising pre‐clinical therapeutic leads. Clinical development will require further advances in our mechanistic understanding of cardiac fibrosis and dissection of the molecular basis for fibrotic remodelling. This review provides an overview of the complexities of cardiac fibrosis, emerging regulatory mechanisms and therapeutic strategies, and highlights knowledge gaps and opportunities for further investigation towards therapeutic/clinical translation.