mRNA modifications in cardiovascular biology and disease: with a focus on m6A modification

M6A modification in cardiovascular disease: With a focus on programmed cell death

N6-methyladenosine (m6A) methylation is one of the most predominant internal RNA modifications in eukaryotes and has become a hot spot in the field of epigenetics in recent years. Cardiovascular diseases (CVDs) are a leading cause of death globally. Emerging evidence demonstrates that RNA modifications, such as the m6A modification, are associated with the development and progression of many diseases, including CVDs. An increasing body of studies has indicated that programmed cell death (PCD) plays a vital role in CVDs. However, the molecular mechanisms underlying m6A modification and PCD in CVDs remain poorly understood. Herein, elaborating on the highly complex connections between the m6A mechanisms and different PCD signaling pathways and clarifying the exact molecular mechanism of m6A modification mediating PCD have significant meaning in developing new strategies for the prevention and therapy of CVDs. There is great potential for clinical application.

ZC3H13 promotes ITGA6 m6A modification for chronic obstructive pulmonary disease progression

Chronic obstructive pulmonary disease (COPD) is potentially fatal, and as society ages, its effects on human health are predicted to deteriorate. The potential function of m6A modifications within COPD has become a hot topic recently. This study was conducted to clarify the function and related mechanisms of the m6A methylation transferase ZC3H13 in COPD. The expression of m6A-associated protease and ITGA6 in COPD tissues was assessed using GEO data, qRT-PCR, and western blot. COPD models in cells and mice were established through cigarette smoke extract (CSE) and smoke exposure. Inflammatory marker levels were measured by ELISA, apoptosis by flow cytometry, and mRNA stability with Actinomycin D assay. m6A modification levels were checked by MeRIP-PCR. HE and Masson staining evaluated lung pathology, and alveolar lavage fluid analysis included total cell count and Giemsa staining. ZC3H13 and METTL3 were differentially expressed m6A regulators in COPD, with ZC3H13 being more significantly upregulated. Further analysis revealed the ZC3H13 expression-related differentially expressed genes (DEGs) functions were enriched in the immunoinflammatory pathway, indicating ZC3H13's involvement in COPD pathogenesis through inflammation, and immune responses. Knockdown studies in cellular and mouse models demonstrated ZC3H13's role in exacerbating COPD symptoms, including inflammation, apoptosis, and EMT, and its suppression led to significant improvements. The identification of ITGA6 as a target gene further elucidated the mechanism, showing that ZC3H13 enhances ITGA6 expression and mRNA stability through m6A modification, influencing bronchial epithelial cell inflammation and fibrosis. In conclusion, targeting ZC3H13/ITGA6 could be an underlying therapeutic approach for treating COPD.

Comprehensive landscape of m6A regulator-related gene patterns and tumor microenvironment infiltration characterization in gastric cancer

The epigenetic regulation of N6-methyladenosine (m6A) has attracted considerable interest in tumor research, but the potential roles of m6A regulator-related genes, remain largely unknown within the context of gastric cancer (GC) and tumor microenvironment (TME). Here, a comprehensive strategy of data mining and computational biology utilizing multiple datasets based on 28 m6A regulators (including novel anti-readers) was employed to identify m6A regulator-related genes and patterns and elucidate their underlying mechanisms in GC. Subsequently, a scoring system was constructed to evaluate individual prognosis and immunotherapy response. Three distinct m6A regulator-related patterns were identified through the unsupervised clustering of 56 m6A regulator-related genes (all significantly associated with GC prognosis). TME characterization revealed that these patterns highly corresponded to immune-inflamed, immune-excluded, and immune-desert phenotypes, and their TME characteristics were highly consistent with different clinical outcomes and biological processes. Additionally, an m6A-related scoring system was developed to quantify the m6A modification pattern of individual samples. Low scores indicated high survival rates and high levels of immune activation, whereas high scores indicated stromal activation and tumor malignancy. Furthermore, the m6A-related scores were correlated with tumor mutation loads and various clinical traits, including molecular or histological subtypes and clinical stage or grade, and the score had predictive values across all digestive system tumors and even in all tumor types. Notably, a low score was linked to improved responses to anti-PD-1/L1 and anti-CTLA4 immunotherapy in three independent cohorts. This study has expanded the important role of m6A regulator-related genes in shaping TME diversity and clinical/biological traits of GC. The developed scoring system could help develop more effective immunotherapy strategies and personalized treatment guidance.

METTL3-m6A methylation inhibits the proliferation and viability of type II alveolar epithelial cells in acute lung injury by enhancing the stability and translation efficiency of Pten mRNA

BACKGROUND

The pathogenesis of acute lung injury (ALI) involves a severe inflammatory response, leading to significant morbidity and mortality. N6-methylation of adenosine (m6A), an abundant mRNA nucleotide modification, plays a crucial role in regulating mRNA metabolism and function. However, the precise impact of m6A modifications on the progression of ALI remains elusive.

METHODS

ALI models were induced by either intraperitoneal injection of lipopolysaccharide (LPS) into C57BL/6 mice or the LPS-treated alveolar type II epithelial cells (AECII) in vitro. The viability and proliferation of AECII were assessed using CCK-8 and EdU assays. The whole-body plethysmography was used to record the general respiratory functions. M6A RNA methylation level of AECII after LPS insults was detected, and then the "writer" of m6A modifications was screened. Afterwards, we successfully identified the targets that underwent m6A methylation mediated by METTL3, a methyltransferase-like enzyme. Last, we evaluated the regulatory role of METTL3-medited m6A methylation at phosphatase and tensin homolog (Pten) in ALI, by assessing the proliferation, viability and inflammation of AECII.

RESULTS

LPS induced marked damages in respiratory functions and cellular injuries of AECII. The m6A modification level in mRNA and the expression of METTL3, an m6A methyltransferase, exhibited a notable rise in both lung tissues of ALI mice and cultured AECII cells subjected to LPS treatment. METTL3 knockdown or inhibition improved the viability and proliferation of LPS-treated AECII, and also reduced the m6A modification level. In addition, the stability and translation of Pten mRNA were enhanced by METTL3-mediated m6A modification, and over-expression of PTEN reversed the protective effect of METTL3 knockdown in the LPS-treated AECII.

CONCLUSIONS

The progression of ALI can be attributed to the elevated levels of METTL3 in AECII, as it promotes the stability and translation of Pten mRNA through m6A modification. This suggests that targeting METTL3 could offer a novel approach for treating ALI.

YTHDC1 aggravates high glucose-induced retinal vascular endothelial cell injury via m6A modification of CDK6

OBJECTIVE

Retinal vascular endothelial cell (RVECs) injury is a major cause of morbidity and mortality among the patients with diabetes. RVECs dysfunction is the predominant pathological manifestation of vascular complication in diabetic retinopathy. N6-methyladenosine (m6A) serves as the most prevalent modification in eukaryotic mRNAs. However, the role of m6A RNA modification in RVECs dysfunction is still unclear.

METHODS

RT-qPCR analysis and western blot were conducted to detect the change of m6A RNA modification in diabetic retinopathy. CCK-8 assay, transwell experiment, wound healing assay, tube formation experiment, m6A-IP-qPCR were performed to determine the role of YTHDC1 in RVECs. Retinal trypsin digestion test and H&E staining were used to evaluate histopathological changes.

RESULTS

The levels of m6A RNA methylation were significantly up-regulated in HG-induced RVECs, which were caused by increased expression of YTHDC1. YTHDC1 regulated the viability, proliferation, migration and tube formation ability in vitro. YTHDC1 overexpression impaired RVECs function by repressing CDK6 expression, which was mediated by YTHDC1-dependent mRNA decay. Moreover, it showed sh-YTHDC1 inhibited CDK6 nuclear export. Sh-YTHDC1 promotes the mRNA degradation of CDK6 in the nucleus but does not affect the cytoplasmic CDK6 mRNA. In vivo experiments showed that overexpression of CDK6 reversed the protective effect of sh-YTHDC1 on STZ-induced retinal tissue damage.

CONCLUSION

YTHDC1-mediated m6A methylation regulates diabetes-induced RVECs dysfunction. YTHDC1-CDK6 signaling axis could be therapeutically targeted for treating DR.

Liquid-liquid phase separation in diseases

Liquid-liquid phase separation (LLPS), an emerging biophysical phenomenon, can sequester molecules to implement physiological and pathological functions. LLPS implements the assembly of numerous membraneless chambers, including stress granules and P-bodies, containing RNA and protein. RNA-RNA and RNA-protein interactions play a critical role in LLPS. Scaffolding proteins, through multivalent interactions and external factors, support protein-RNA interaction networks to form condensates involved in a variety of diseases, particularly neurodegenerative diseases and cancer. Modulating LLPS phenomenon in multiple pathogenic proteins for the treatment of neurodegenerative diseases and cancer could present a promising direction, though recent advances in this area are limited. Here, we summarize in detail the complexity of LLPS in constructing signaling pathways and highlight the role of LLPS in neurodegenerative diseases and cancers. We also explore RNA modifications on LLPS to alter diseases progression because these modifications can influence LLPS of certain proteins or the formation of stress granules, and discuss the possibility of proper manipulation of LLPS process to restore cellular homeostasis or develop therapeutic drugs for the eradication of diseases. This review attempts to discuss potential therapeutic opportunities by elaborating on the connection between LLPS, RNA modification, and their roles in diseases.

Protective effect of vitexin against high fat-induced vascular endothelial inflammation through inhibiting trimethylamine N-oxide-mediated RNA m6A modification

A high-fat diet (HFD) is a major risk factor for cardiovascular disease. However, the specific effects of a HFD on vascular inflammation and the protective role of vitexin, a bioactive compound derived from food, require further research. This study investigated the protective effects of vitexin intervention against HFD-induced vascular inflammation and its underlying mechanism. The results demonstrated that vitexin intervention significantly reduced body weight, serum total cholesterol, and low-density lipoprotein cholesterol levels in HFD-fed mice. Vitexin also improved vascular pathological changes and the inflammatory status in the mice. Furthermore, vitexin intervention reduced serum TMAO levels in HFD-fed mice by altering the gut microbiota composition. The HFD significantly increased N6-methyladenosine (m6A) levels in aorta tissues, while vitexin intervention reversed this abnormal m6A level. Through metabolite affinity responsive target fluorescence quenching and molecular docking assays, it was found that vitexin could directly bind to fat mass and obesity-associated protein (FTO), potentially promoting m6A demethylation. The dose-response relationship between TMAO and inflammation/m6A was further validated in HUVEC cells and in vivo mouse experiments. Specifically, TMAO increased m6A levels and inflammation, while vitexin inhibited TMAO-mediated m6A modification, exhibiting anti-inflammatory effects. In conclusion, this study demonstrates the protective role of vitexin against HFD-induced vascular inflammation by inhibiting TMAO-mediated RNA m6A modification, laying the foundation for the development of functional foods.

hsa_circ_0101050 regulated by ZC3H13 enhances tumorigenesis in papillary thyroid cancer via m6A modification

While the regulatory roles of circular RNAs (circRNAs) and zinc finger CCCH-type containing 13 (ZC3H13) were previously reported in various human cancers, the mechanisms underlying their interaction in papillary thyroid cancer (PTC) remain unclear. We aimed to determine the role of hsa_circ_0101050 and its regulatory relationship with ZC3H13 in PTC. The expression levels of hsa_circ_0101050 and ZC3H13 were determined in tumor samples and adjacent normal tissues from 46 patients with PTC and in two PTC cell lines (IHH-4 and PTC-1) using quantitative reverse transcription-polymerase chain reaction. The roles of hsa_circ_0101050 and ZC3H13 in cell viability, wound healing, and migration were determined using knockdown and overexpression approaches in PTC cell lines, and a xenograft model in nude mice was used to determine their role in vivo. Methylated RNA immunoprecipitation assay was used to analyze N6-methyladenosine (m6A) modification of hsa_circ_0101050 by ZC3H13. We found hsa_circ_0101050 overexpression and ZC3H13 downregulation in PTC samples and PTC cell lines. In PTC cell lines, silencing hsa_circ_0101050 reduced cell viability and migration whereas its overexpression promoted an aggressive PTC phenotype. ZC3H13 increased the m6A modification of hsa_circ_0101050 and repressed its expression. ZC3H13 overexpression inhibited PTC cell viability, migration, and invasion, which were reversed in cells overexpressing hsa_circ_0101050. Taken together, these results suggested that the downregulation of hsa_circ_0101050 mediated by ZC3H13 through m6A modification contributed to its oncogenic effect in PTC development, revealing the ZC3H13-m6A-hsa_circ_0101050 as a potential therapeutic target in PTC.

Characterization of the Expressions and m6A Methylation Modification Patterns of mRNAs and lncRNAs in a Spinal Cord Injury Rat Model

Spinal cord injury (SCI) is a serious central nervous system disease with no effective treatment strategy presently due to its complex pathogenic mechanism. N6-methyladenosine (m6A) methylation modification plays an important role in diverse physiological and pathological processes. However, our understanding of the potential mechanisms of messenger RNA (mRNA) and long non-coding RNAs (lncRNA) m6A methylation in SCI is currently limited. Here, comprehensive m6A profiles and gene expression patterns of mRNAs and lncRNAs in spinal cord tissues after SCI were identified using microarray analysis of immunoprecipitated methylated RNAs. A total of 3745 mRNAs (2343 hypermethylated and 1402 hypomethylated) and 738 lncRNAs (488 hypermethylated and 250 hypomethylated) were differentially methylated with m6A modifications in the SCI and sham rats. Functional analysis revealed that differentially m6A-modified mRNAs were mainly involved in immune inflammatory response, nervous system development, and focal adhesion pathway. In contrast, differentially m6A-modified lncRNAs were mainly related to antigen processing and presentation, the apoptotic process, and the mitogen-activated protein kinases (MAPKs) signaling pathway. In addition, combined analysis of m6A methylation and RNA expression results revealed that 1636 hypermethylated mRNAs and 262 hypermethylated lncRNAs were up-regulated, and 1571 hypomethylated mRNAs and 204 lncRNAs were down-regulated. Furthermore, we validated the altered levels of m6A methylation and RNA expression of five mRNAs (CD68, Gpnmb, Lilrb4, Lamp5, and Snap25) and five lncRNAs (XR_360518, uc.393 + , NR_131064, uc.280 - , and XR_597251) using MeRIP-qPCR and qRT-PCR. This study expands our understanding of the molecular mechanisms underlying m6A modification in SCI and provides novel insights to promote functional recovery after SCI.

RNA epigenetic modifications in digestive tract cancers: Friends or foes

Digestive tract cancers are among the most common malignancies worldwide and have high incidence and mortality rates. Thus, the discovery of more effective diagnostic and therapeutic targets is urgently required. The development of technologies to accurately detect RNA modification has led to the identification of numerous RNA chemical modifications in humans (epitranscriptomics) that are involved in the occurrence and development of digestive tract cancers. RNA modifications can cooperatively regulate gene expression to facilitate normal physiological functions of the digestive system. However, the dysfunction of relevant RNA-modifying enzymes ("writers," "erasers," and "readers") can lead to the development of digestive tract cancers. Consequently, targeting dysregulated enzyme activity could represent a potent therapeutic strategy for the treatment of digestive tract cancers. In this review, we summarize the most widely studied roles and mechanisms of RNA modifications (m6A, m1A, m5C, m7G, A-to-I editing, pseudouridine [Ψ]) in relation to digestive tract cancers, highlight the crosstalk between RNA modifications, and discuss their roles in the interactions between the digestive system and microbiota during carcinogenesis. The clinical significance of novel therapeutic methods based on RNA-modifying enzymes is also discussed. This review will help guide future research into digestive tract cancers that are resistant to current therapeutics.

N6-methyladenosine demethylase fat mass and obesity-associated protein suppresses hyperglycemia-induced endothelial cell injury by inhibiting reactive oxygen species formation via autophagy promotion

INTRODUCTION

Hyperglycemia-induced endothelial cell injury is one of the main causes of diabetic vasculopathy. Fat mass and obesity-associated protein (FTO) was the first RNA N6-methyladenosine (m6A) demethylase identified; it participates in the pathogenesis of diabetes. However, the role of FTO in hyperglycemia-induced vascular endothelial cell injury remains unclear.

MATERIALS AND METHODS

The effects of FTO on cellular m6A, autophagy, oxidative stress, proliferation, and cytotoxicity were explored in human umbilical vein endothelial cells (HUVECs) treated with high glucose (33.3 mmol/mL) after overexpression or pharmacological inhibition of FTO. MeRIP-qPCR and RNA stability assays were used to explore the molecular mechanisms by which FTO regulates autophagy.

RESULTS

High glucose treatment increased m6A levels and reduced FTO protein expression in HUVECs. Wild-type overexpression of FTO markedly inhibited reactive oxygen species generation by promoting autophagy, increasing endothelial cell proliferation, and decreasing the cytotoxicity of high glucose concentrations. The pharmacological inhibition of FTO showed the opposite results. Mechanistically, we identified Unc-51-like kinase 1 (ULK1), a gene responsible for autophagosome formation, as a downstream target of FTO-mediated m6A modification. FTO overexpression demethylated ULK1 mRNA and inhibited its degradation in an m6A-YTHDF2-dependent manner, leading to autophagy activation.

CONCLUSIONS

Our study demonstrates the functional importance of FTO-mediated m6A modification in alleviating endothelial cell injury under high glucose conditions and indicates that FTO may be a novel therapeutic target for diabetic vascular complications.

m6A epitranscriptomic modification of inflammation in cardiovascular disease

Cardiovascular disease is currently the number one cause of death endangering human health. There is currently a large body of research showing that the development of cardiovascular disease and its complications is often accompanied by inflammatory processes. In recent years, epitranscriptional modifications have been shown to be involved in regulating the pathophysiological development of inflammation in cardiovascular diseases, with 6-methyladenine being one of the most common RNA transcriptional modifications. In this review, we link different cardiovascular diseases, including atherosclerosis, heart failure, myocardial infarction, and myocardial ischemia-reperfusion, with inflammation and describe the regulatory processes involved in RNA methylation. Advances in RNA methylation research have revealed the close relationship between the regulation of transcriptome modifications and inflammation in cardiovascular diseases and brought potential therapeutic targets for disease diagnosis and treatment. At the same time, we also discussed different cell aspects. In addition, in the article we also describe the different application aspects and clinical pathways of RNA methylation therapy. In summary, this article reviews the mechanism, regulation and disease treatment effects of m6A modification on inflammation and inflammatory cells in cardiovascular diseases in recent years. We will discuss issues facing the field and new opportunities that may be the focus of future research.

Crosstalk between Epigenetics and Metabolic Reprogramming in Metabolic Dysfunction-Associated Steatotic Liver Disease-Induced Hepatocellular Carcinoma: A New Sight

Epigenetic and metabolic reprogramming alterations are two important features of tumors, and their reversible, spatial, and temporal regulation is a distinctive hallmark of carcinogenesis. Epigenetics, which focuses on gene regulatory mechanisms beyond the DNA sequence, is a new entry point for tumor therapy. Moreover, metabolic reprogramming drives hepatocellular carcinoma (HCC) initiation and progression, highlighting the significance of metabolism in this disease. Exploring the inter-regulatory relationship between tumor metabolic reprogramming and epigenetic modification has become one of the hot directions in current tumor metabolism research. As viral etiologies have given way to metabolic dysfunction-associated steatotic liver disease (MASLD)-induced HCC, it is urgent that complex molecular pathways linking them and hepatocarcinogenesis be explored. However, how aberrant crosstalk between epigenetic modifications and metabolic reprogramming affects MASLD-induced HCC lacks comprehensive understanding. A better understanding of their linkages is necessary and urgent to improve HCC treatment strategies. For this reason, this review examines the interwoven landscape of molecular carcinogenesis in the context of MASLD-induced HCC, focusing on mechanisms regulating aberrant epigenetic alterations and metabolic reprogramming in the development of MASLD-induced HCC and interactions between them while also updating the current advances in metabolism and epigenetic modification-based therapeutic drugs in HCC.

RNA modifications in physiology and pathology: Progressing towards application in clinical settings

The potential to modify individual nucleotides through chemical means in order to impact the electrostatic charge, hydrophobic properties, and base pairing of RNA molecules is harnessed in the medical application of stable synthetic RNAs like mRNA vaccines and synthetic small RNA molecules. These modifications are used to either increase or decrease the production of therapeutic proteins. Additionally, naturally occurring biochemical alterations of nucleotides play a role in regulating RNA metabolism and function, thereby modulating essential cellular processes. Research elucidating the mechanisms through which RNA modifications govern fundamental cellular functions in multicellular organisms has enhanced our comprehension of how irregular RNA modification profiles can lead to human diseases. Collectively, these fundamental scientific findings have unveiled the molecular and cellular functions of RNA modifications, offering new opportunities for therapeutic intervention and paving the way for a variety of innovative clinical strategies.

The potential mechanism of WT1-associated protein-induced N-6-methyladenosine modification of colony-stimulating factor 2 in the progression of oral squamous cell carcinoma by JAK/STAT3 pathway regulation

Colony-stimulating factor 2 (CSF2) plays a regulatory role in numerous cancers. However, there is needed to investigate the role of CSF2 in oral squamous cell carcinoma (OSCC) malignant phenotype and the specific mechanisms of CSF2 N-6-methyladenosine (m6A) modification. Therefore, we investigated the regulatory mechanism of m6A-modified CSF2 by WT1-associated protein (WTAP) in OSCC via qRT-PCR, western blot, WTAP and CSF2 overexpression in OSCC. In a panel of OSCCs, Kaplan-Meier plot analysis indicated that high expression of CSF2 was associated with poorer prognosis. Cell functional experiments revealed that enrichment of CSF2 promoted the proliferation and migration of OSCC cells by activating the JAK/STAT3 pathway, whereas the reduced expression of CSF2 resulted in the malignant decline of OSCC cells by blocking the JAK/STAT3 pathway. This study also confirmed that WTAP enhanced the m6A level of CSF2 and facilitated the expression of CSF2 and that CSF2 silencing blocked the invasive phenotype of OSCC cells and reversed the malignancy induced by WTAP overexpression. Overall, this study demonstrated that WTAP mediates the m6A modification of CSF2 and the JAK/STAT3 pathway, which plays an oncogenic role in the development of OSCC and can be a target for the treatment of patients with OSCC.

Deciphering m6A methylation in monocyte-mediated cardiac fibrosis and monocyte-hitchhiked erythrocyte microvesicle biohybrid therapy

Rationale: Device implantation frequently triggers cardiac remodeling and fibrosis, with monocyte-driven inflammatory responses precipitating arrhythmias. This study investigates the role of m6A modification enzymes METTL3 and METTL14 in these responses and explores a novel therapeutic strategy targeting these modifications to mitigate cardiac remodeling and fibrosis. Methods: Peripheral blood mononuclear cells (PBMCs) were collected from patients with ventricular septal defects (VSD) who developed conduction blocks post-occluder implantation. The expression of METTL3 and METTL14 in PBMCs was measured. METTL3 and METTL14 deficiencies were induced to evaluate their effect on angiotensin II (Ang II)-induced myocardial inflammation and fibrosis. m6A modifications were analyzed using methylated RNA immunoprecipitation followed by quantitative PCR. NF-κB pathway activity and levels of monocyte migration and fibrogenesis markers (CXCR2 and TGF-β1) were assessed. An erythrocyte microvesicle-based nanomedicine delivery system was developed to target activated monocytes, utilizing the METTL3 inhibitor STM2457. Cardiac function was evaluated via echocardiography. Results: Significant upregulation of METTL3 and METTL14 was observed in PBMCs from patients with VSD occluder implantation-associated persistent conduction block. Deficiencies in METTL3 and METTL14 significantly reduced Ang II-induced myocardial inflammation and fibrosis by decreasing m6A modification on MyD88 and TGF-β1 mRNAs. This disruption reduced NF-κB pathway activation, lowered CXCR2 and TGF-β1 levels, attenuated monocyte migration and fibrogenesis, and alleviated cardiac remodeling. The erythrocyte microvesicle-based nanomedicine delivery system effectively targeted inflamed cardiac tissue, reducing inflammation and fibrosis and improving cardiac function. Conclusion: Inhibiting METTL3 and METTL14 in monocytes disrupts the NF-κB feedback loop, decreases monocyte migration and fibrogenesis, and improves cardiac function. Targeting m6A modifications of monocytes with STM2457, delivered via erythrocyte microvesicles, reduces inflammation and fibrosis, offering a promising therapeutic strategy for cardiac remodeling associated with device implantation.

Inhibition of METTL3 ameliorates doxorubicin-induced cardiotoxicity through suppression of TFRC-mediated ferroptosis

BACKGROUND

Doxorubicin (DOX) is a chemotherapeutic drug, while its clinical use is greatly limited by the life-threatening cardiotoxicity. N6-methyladenosine (m6A) RNA modification participates in varieties of cellular processes. Nonetheless, it remains elusive whether m6A modification and its methyltransferase METTL3 are involved in the progression of DOX-induced cardiotoxicity (DIC).

METHODS

Mice were administrated with DOX (accumulative dosage of 20 mg/kg) repeatedly to establish a chronic DIC model. Cardiomyocyte-specific conditional METTL3 knockout mice were employed to evaluate the effects of altered m6A RNA modification on DIC. The effects of METTL3 on cardiomyocyte ferroptosis were also examined in response to DOX stimulation.

RESULTS

DOX led to increased levels in m6A modification and METTL3 expression in cardiomyocytes in a c-Jun-dependent manner. METTL3-knockout mice exhibited improved cardiac function, remodeling and injury following DOX insult. Besides, inhibition of METTL3 alleviated DOX-induced iron accumulation and ferroptosis in cardiomyocytes, whereas METTL3 overexpression exerted the opposite effects. Mechanistically, METTL3 promoted m6A modification of TFRC mRNA, a critical gene governing iron uptake, and enhanced its stability through recognition of the m6A reader protein, IGF2BP2. Moreover, pharmacological administration of a highly selective METTL3 inhibitor STM2457 effectively ameliorated DIC in mice.

CONCLUSION

METTL3 plays a cardinal role in the etiology of DIC by regulating cardiac iron metabolism and ferroptosis through TFRC m6A modification. Inhibition of METTL3 might be a potential therapeutic avenue for DIC.

Ubiquitin ligase TRIM15 promotes the progression of pancreatic cancer via the upregulation of the IGF2BP2-TLR4 axis

BACKGROUND

The tripartite motif family, predominantly characterized by its E3 ubiquitin ligase activities, is involved in various cellular processes including signal transduction, apoptosis and autophagy, protein quality control, immune regulation, and carcinogenesis. Tripartite Motif Containing 15 (TRIM15) plays an important role in melanoma progression through extracellular signal-regulated kinase activation; however, data on its role in pancreatic tumors remain lacking. We previously demonstrated that TRIM15 targeted lipid synthesis and metabolism in pancreatic cancer; however, other specific regulatory mechanisms remain elusive.

METHODS

We used transcriptomics and proteomics, conducted a series of phenotypic experiments, and used a mouse orthotopic transplantation model to study the specific mechanism of TRIM15 in pancreatic cancer in vitro and in vivo.

RESULTS

TRIM15 overexpression promoted the progression of pancreatic cancer by upregulating the toll-like receptor 4. The TRIM15 binding protein, IGF2BP2, could combine with TLR4 to inhibit its mRNA degradation. Furthermore, the ubiquitin level of IGF2BP2 was positively correlated with TRIM15.

CONCLUSIONS

TRIM15 could ubiquitinate IGF2BP2 to enhance the function of phase separation and the maintenance of mRNA stability of TLR4. TRIM15 is a potential therapeutic target against pancreatic cancer.

Critical role of the long non-coding RNAs (lncRNAs) in radiotherapy (RT)-resistance of gastrointestinal (GI) cancer: Is there a way to defeat this resistance?

Radiotherapy (RT) is a frequently used treatment for cervical cancer, effectively decreasing the likelihood of the disease returning in the same area and extending the lifespan of individuals with cervical cancer. Nevertheless, the primary reason for treatment failure in cancer patients is the cancer cells' resistance to radiation therapy (RT). Long non-coding RNAs (LncRNAs) are a subset of RNA molecules that do not code for proteins and are longer than 200 nucleotides. They have a significant impact on the regulation of gastrointestinal (GI) cancers biological processes. Recent research has shown that lncRNAs have a significant impact in controlling the responsiveness of GI cancer to radiation. This review provides a concise overview of the composition and operation of lncRNAs as well as the intricate molecular process behind radiosensitivity in GI cancer. Additionally, it compiles a comprehensive list of lncRNAs that are linked to radiosensitivity in such cancers. Furthermore, it delves into the potential practical implementation of these lncRNAs in modulating radiosensitivity in GI cancer.

The biological function of the N6-Methyladenosine reader YTHDC2 and its role in diseases

N6-methyladenosine (m6A) stands as the most prevalent modified form of RNA in eukaryotes, pivotal in various biological processes such as regulating RNA stability, translation, and transcription. All members within the YT521-B homology (YTH) gene family are categorized as m6A reading proteins, capable of identifying and binding m6A modifications on RNA, thereby regulating RNA metabolism and functioning across diverse physiological processes. YTH domain-containing 2 (YTHDC2), identified as the latest member of the YTH family, has only recently started to emerge for its biological function. Numerous studies have underscored the significance of YTHDC2 in human physiology, highlighting its involvement in both tumor progression and non-tumor diseases. Consequently, this review aims to further elucidate the pathological mechanisms of YTHDC2 by summarizing its functions and roles in tumors and other diseases, with a particular focus on its downstream molecular targets and signaling pathways.

YTHDF2-Mediated m6A methylation inhibition by miR27a as a protective mechanism against hormonal osteonecrosis in BMSCs

BACKGROUND

With the increasing incidence of steroid-induced necrosis of the femoral head (SNFH), numerous scholars have investigated its pathogenesis. Current evidence suggests that the imbalance between lipogenesis and osteoblast differentiation in bone marrow mesenchymal stem cells (BMSCs) is a key pathological feature of SNFH. MicroRNAs (miRNAs) have strong gene regulatory effects and can influence the direction of cell differentiation. N6-methyladenosine (m6A) is a prevalent epigenetic modification involved in diverse pathophysiological processes. However, knowledge of how miRNAs regulate m6A-related factors that affect BMSC differentiation is limited.

OBJECTIVE

We aimed to investigate the role of miR27a in regulating the expression of YTHDF2 in BMSCs.

METHODS

We compared miR27a, YTHDF2, and total m6A mRNA levels in SNFH-affected and control BMSCs. CCK-8 and TUNEL assays were used to assess BMSC proliferation and apoptosis. Western blotting and qRT‒PCR were used to measure the expression of osteogenic (ALP, RUNX2, and OCN) and lipogenic (PPARγ and C/EBPα) markers. Alizarin Red and Oil Red O staining were used to quantify osteogenic and lipogenic differentiation, respectively. miR27a was knocked down or overexpressed to evaluate its impact on BMSC differentiation and its relationship with YTHDF2. Bioinformatics analyses identified YTHDF2 as a differentially expressed gene in SNFH (ROC analysis) and revealed potential signaling pathways through GSEA. The effects of YTHDF2 silencing on the lipogenic and osteogenic functions of BMSCs were assessed.

RESULTS

miR27a downregulation and YTHDF2 upregulation were observed in the SNFH BMSCs. miR27a knockdown/overexpression modulated YTHDF2 expression, impacting BMSC differentiation. miR27a silencing decreased m6A methylation and promoted osteogenic differentiation, while YTHDF2 silencing exerted similar effects. GSEA suggested potential signaling pathways associated with YTHDF2 in SNFH.

CONCLUSION

miR27a regulates BMSC differentiation through YTHDF2, affecting m6A methylation and promoting osteogenesis. This finding suggests a potential therapeutic target for SNFH.

RNA m6A methylation and regulatory proteins in pulmonary arterial hypertension

m6A (N6‑methyladenosine) is the most common and abundant apparent modification in mRNA of eukaryotes. The modification of m6A is regulated dynamically and reversibly by methyltransferase (writer), demethylase (eraser), and binding protein (reader). It plays a significant role in various processes of mRNA metabolism, including regulation of transcription, maturation, translation, degradation, and stability. Pulmonary arterial hypertension (PAH) is a malignant cardiopulmonary vascular disease characterized by abnormal proliferation of pulmonary artery smooth muscle cells. Despite the existence of several effective and targeted therapies, there is currently no cure for PAH and the prognosis remains poor. Recent studies have highlighted the crucial role of m6A modification in cardiovascular diseases. Investigating the role of RNA m6A methylation in PAH could provide valuable insights for drug development. This review aims to explore the mechanism and function of m6A in the pathogenesis of PAH and discuss the potential targeting of RNA m6A methylation modification as a treatment for PAH.

Biological significance of METTL5 in atherosclerosis: comprehensive analysis of single-cell and bulk RNA sequencing data

BACKGROUND

N6-methyladenosine (m6A) methylation is involved in the pathogenesis of atherosclerosis (AS). Limited studies have examined the role of the m6A methyltransferase METTL5 in AS pathogenesis.

METHODS

This study subjected the AS dataset to differential analysis and weighted gene co-expression network analysis to identify m6A methylation-associated differentially expressed genes (DEGs). Next, the m6A methylation-related DEGs were subjected to consensus clustering to categorize AS samples into distinct m6A subtypes. Single-cell RNA sequencing (scRNA-seq) analysis was performed to investigate the proportions of each cell type in AS and adjacent healthy tissues and the expression levels of key m6A regulators. The mRNA expression levels of METTL5 in AS and healthy tissues were determined using quantitative real-time polymerase chain reaction (qRT-PCR) analysis.

RESULTS

AS samples were classified into two subtypes based on a five-m6A regulator-based model. scRNA-seq analysis revealed that the proportions of T cells, monocytes, and macrophages in AS tissues were significantly higher than those in healthy tissues. Additionally, the levels of m6A methylation were significantly different between AS and healthy tissues. METTL5 expression was upregulated in macrophages, smooth muscle cells (SMCs), and endothelial cells (ECs). qRT-PCR analysis demonstrated that the METTL5 mRNA level in AS tissues was downregulated when compared with that in healthy tissues.

CONCLUSIONS

METTL5 is a potential diagnostic marker for AS subtypes. Macrophages, SMCs, and ECs, which exhibit METTL5 upregulation, may modulate AS progression by regulating m6A methylation levels.

Exercise training decreases lactylation and prevents myocardial ischemia-reperfusion injury by inhibiting YTHDF2

Exercise improves cardiac function and metabolism. Although long-term exercise leads to circulating and micro-environmental metabolic changes, the effect of exercise on protein post-translational lactylation modifications as well as its functional relevance is unclear. Here, we report that lactate can regulate cardiomyocyte changes by improving protein lactylation levels and elevating intracellular N6-methyladenosine RNA-binding protein YTHDF2. The intrinsic disorder region of YTHDF2 but not the RNA m6A-binding activity is indispensable for its regulatory function in influencing cardiomyocyte cell size changes and oxygen glucose deprivation/re-oxygenation (OGD/R)-stimulated apoptosis via upregulating Ras GTPase-activating protein-binding protein 1 (G3BP1). Downregulation of YTHDF2 is required for exercise-induced physiological cardiac hypertrophy. Moreover, myocardial YTHDF2 inhibition alleviated ischemia/reperfusion-induced acute injury and pathological remodeling. Our results here link lactate and lactylation modifications with RNA m6A reader YTHDF2 and highlight the physiological importance of this innovative post-transcriptional intrinsic regulation mechanism of cardiomyocyte responses to exercise. Decreasing lactylation or inhibiting YTHDF2/G3BP1 might represent a promising therapeutic strategy for cardiac diseases.

Characterization of the m6A regulators' landscape highlights the clinical significance of acute myocardial infarction

Objective

Acute myocardial infarction (AMI) is a severe cardiovascular disease that threatens human life and health globally. N6-methyladenosine (m6A) governs the fate of RNAs via m6A regulators. Nevertheless, how m6A regulators affect AMI remains to be deciphered. To solve this issue, an integrative analysis of m6A regulators in AMI was conducted.

Methods

We acquired transcriptome profiles (GSE59867, GSE48060) of peripheral blood samples from AMI patients and healthy controls. Key m6A regulators were used for LASSO, and consensus clustering was conducted. Next, the m6A score was also computed. Immune cell infiltration, ferroptosis, and oxidative stress were evaluated. In-vitro and in-vivo experiments were conducted to verify the role of the m6A regulator ALKBH5 in AMI.

Results

Most m6A regulators presented notable expression alterations in circulating cells of AMI patients versus those of controls. Based on key m6A regulators, we established a gene signature and a nomogram for AMI diagnosis and risk prediction. AMI patients were classified into three m6A clusters or gene clusters, respectively, and each cluster possessed the unique properties of m6A modification, immune cell infiltration, ferroptosis, and oxidative stress. Finally, the m6A score was utilized to quantify m6A modification patterns. Therapeutic targeting of ALKBH5 greatly alleviated apoptosis and intracellular ROS in H/R-induced H9C2 cells and NRCMs.

Conclusion

Altogether, our findings highlight the clinical significance of m6A regulators in the diagnosis and risk prediction of AMI and indicate the critical roles of m6A modification in the regulation of immune cell infiltration, ferroptosis, and oxidative stress.

Colchicine Blocks Abdominal Aortic Aneurysm Development by Maintaining Vascular Smooth Muscle Cell Homeostasis

Development of non-surgical treatment of human abdominal aortic aneurysm (AAA) has clinical significance. Colchicine emerges as an effective therapeutic regimen in cardiovascular diseases. Yet, whether colchicine slows AAA growth remain controversy. Here, we demonstrated that daily intragastric administration of low-dose colchicine blocked AAA formation, prevented vascular smooth muscle cell (SMC) phenotype switching and apoptosis, and vascular inflammation in both peri-aortic CaPO4 injury and subcutaneous angiotensin-II infusion induced experimental AAA mice models. Mechanistically, colchicine increased global mRNA stability by inhibiting the METTL14/YTHDC1-mediated m6A modification, resulting in increased sclerostin (SOST) expression and consequent inactivation of the WNT/β-catenin signaling pathway in vascular SMCs from mouse AAA lesions and in cultured human aortic SMCs. Moreover, human and mouse AAA lesions all showed increased m6A methylation, decreased SOST expression, and skewed synthetic SMC de-differentiation phenotype, compared to those without AAA. This study uncovers a novel mechanism of colchicine in slowing AAA development by using the METTL14/SOST/WNT/β-catenin axis to control vascular SMC homeostasis in mouse aortic vessels and in human aortic SMCs. Therefore, use of colchicine may benefit AAA patients in clinical practice.

FTO-mediated autophagy inhibition promotes non-small cell lung cancer progression by reducing the stability of SESN2 mRNA

The role of fat mass and obesity-associated protein (FTO), an N6-methyladenosine (m6A) demethylase, in non-small cell lung cancer (NSCLC) has recently received widespread attention. However the underlying mechanisms of FTO-mediated autophagy regulation in NSCLC progression remain elusive. In this study, we found that FTO was significantly upregulated in NSCLC, and downregulation of FTO suppressed the growth, invasion and migration of NSCLC cells by inducing autophagy. FTO knockdown resulted in elevated m6A levels in NSCLC cells. Methylated RNA immunoprecipitation sequencing showed that sestrin 2 (SESN2) was involved in m6A regulation during autophagy in NSCLC cells. Interestingly, m6A modifications in exon 9 of SESN2 regulated its stability. FTO deficiency promoted the binding of insulin-like growth factor 2 mRNA-binding protein 1 to SESN2 mRNA, enhancing its stability and elevating its protein expression. FTO inhibited autophagic flux by downregulating SESN2, thereby promoting the growth, invasion and migration of NSCLC cells. Besides, the mechanism by which FTO blocked SESN2-mediated autophagy activation was associated with the AMPK-mTOR signaling pathway. Taken together, these findings uncover an essential role of the FTO-autophagy-SESN2 axis in NSCLC progression.

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.

Prenatal Nicotine Exposure Raises Male Blood Pressure via FTO-Mediated NOX2/ROS Signaling

BACKGROUND

Cigarette smoking/nicotine exposure in pregnancy shows an increased risk of hypertension in offspring, but the mechanisms are unclear. This study tested the hypothesis that m6A RNA hypomethylation epigenetically regulates vascular NOX (NADPH oxidase) and reactive oxygen species production, contributing to the fetal programming of a hypertensive phenotype in nicotine-exposed offspring.

METHODS

Pregnant rats were exposed to episodic chronic intermittent nicotine aerosol (CINA) or saline aerosol control from gestational day 4 to day 21, and experiments were performed in 6-month-old adult offspring.

RESULTS

Antenatal CINA exposure augmented Ang II (angiotensin II)-stimulated blood pressure response in male, but not female offspring. Moreover, CINA increased vascular NOX2 expression and superoxide production exclusively in male offspring. Inhibition of NOX2 with gp91ds-tat, both ex vivo and in vivo, mitigated the CINA-induced elevation in superoxide production and blood pressure response. Notably, CINA enhanced the expression of vascular m6A demethylase FTO (fat mass and obesity-associated protein), while reducing the total vascular m6A abundance and specific m6A methylation of the NOX2 gene. Additionally, ex vivo inhibition of FTO with FB23-2 attenuated CINA-induced increases in vascular NOX2 expression. In vitro experiments using human umbilical vein endothelial cells demonstrated that nicotine dose-dependently upregulated FTO and NOX2 protein abundance, which were reversed by treatment with the FTO inhibitor FB23-2 or FTO knockdown using siRNAs.

CONCLUSIONS

This study uncovers a new mechanism: m6A demethylase FTO-mediated epigenetic upregulation of vascular NOX2 signaling in CINA-induced hypertensive phenotype. This insight could lead to a therapeutic target for preventing and treating developmental hypertension programming.

Alkylation Repair Homolog 5 Regulates N(6)-methyladenosine (m6A) Methylation of Mitsugumin 53 to Attenuate Myocardial Infarction by Inhibiting Apoptosis and Oxidative Stress

ABSTRACT

N(6)-methyladenosine (m6A) methylation modification is involved in the progression of myocardial infarction (MI). In this study, we investigated the effects of demethylase alkylation repair homolog 5 (ALKBH5) on cell apoptosis and oxidative stress in MI. The ischemia/reperfusion (I/R) injury mouse model and hypoxia/reoxygenation (H/R) cell model were established. The levels of ALKBH5 and mitsugumin 53 (MG53) were measured by quantitative real-time polymerase chain reaction, immunohistochemical, and immunofluorescence analysis. Apoptosis was evaluated by TUNEL assay, flow cytometry, and western blot. Oxidative stress was assessed by antioxidant index kits. Methylation was analyzed by RNA binding protein immunoprecipitation (RIP), MeRIP, and dual-luciferase reporter assay. We observed that ALKBH5 and MG53 were highly expressed in MI. Overexpression of ALKBH5 inhibited H/R-induced cardiomyocyte apoptosis and oxidative stress in vitro, and it inhibited I/R-induced collagen deposition, cardiac function, and apoptosis in vivo. ALKBH5 could bind to MG53, inhibit m6A methylation of MG53, and increase its mRNA stability. Silencing of MG53 counteracted the inhibition of apoptosis and oxidative stress induced by ALKBH5. In conclusion, ALKBH5 suppressed m6A methylation of MG53 and inhibited MG53 degradation to inhibit apoptosis and oxidative stress of cardiomyocytes, thereby attenuating MI. The results provided a theoretical basis that ALKBH5 is a potential target for MI treatment.

m6A-Mediated Upregulation of Imprinted in Prader-Willi Syndrome Induces Aberrant Apical-Basal Polarization and Oxidative Damage in RPE Cells

Purpose

To reveal the clinical significance, pathological involvement and molecular mechanism of imprinted in Prader-Willi syndrome (IPW) in RPE anomalies that contribute to AMD.

Methods

IPW expression under pathological conditions were detected by microarrays and qPCR assays. In vitro cultured fetal RPE cells were used to study the pathogenicity induced by IPW overexpression and to analyze its upstream and downstream regulatory networks.

Results

We showed that IPW is upregulated in the macular RPE-choroid tissue of dry AMD patients and in fetal RPE cells under oxidative stress, inflammation and dedifferentiation. IPW overexpression in fetal RPE cells induced aberrant apical-basal polarization as shown by dysregulated polarized markers, disrupted tight and adherens junctions, and inhibited phagocytosis. IPW upregulation was also associated with RPE oxidative damages, as demonstrated by intracellular accumulation of reactive oxygen species, reduced cell proliferation, and accelerated cell apoptosis. Mechanically, N6-methyladenosine level of the IPW transcript regulated its stability with YTHDC1 as the reader. IPW mediated RPE features by suppressing MEG3 expression to sequester its inhibition on the AKT serine-threonine kinase (AKT)/mammalian target of rapamycin (mTOR) pathway. We also noticed that the mTOR inhibitor rapamycin suppresses the AKT/mTOR pathway to alleviate the IPW-induced RPE anomalies.

Conclusions

We revealed that IPW overexpression in RPE induces aberrant apical-basal polarization and oxidative damages, thus contributing to AMD progression. We also annotated the upstream and downstream regulatory networks of IPW in RPE. Our findings shed new light on the molecular mechanisms of RPE dysfunctions, and indicate that IPW blockers may be a promising option to treat RPE abnormalities in AMD.

Demethylase FTO inhibits the occurrence and development of triple-negative breast cancer by blocking m 6A-dependent miR-17-5p maturation-induced ZBTB4 depletion

Triple-negative breast cancer (TNBC) is a subtype of breast cancer, and its mechanisms of occurrence and development remain unclear. In this study, we aim to investigate the role and molecular mechanisms of the demethylase FTO (fat mass and obesity-associated protein) in TNBC. Through analysis of public databases, we identify that FTO may regulate the maturation of miR-17-5p and subsequently influence the expression of zinc finger and BTB domain-containing protein 4 (ZBTB4), thereby affecting the occurrence and progression of TNBC. We screen for relevant miRNAs and mRNAs from the GEO and TCGA databases and find that the FTO gene may play a crucial role in TNBC. In vitro cell experiments demonstrate that overexpression of FTO can suppress the proliferation, migration, and invasion ability of TNBC cells and can regulate the maturation of miR-17-5p through an m 6A-dependent mechanism. Furthermore, we establish a xenograft nude mouse model and collect clinical samples to further confirm the role and impact of the FTO/miR-17-5p/ZBTB4 regulatory axis in TNBC. Our findings unveil the potential role of FTO and its underlying molecular mechanisms in TNBC, providing new perspectives and strategies for the research and treatment of TNBC.

The METTL3/miR-196a Axis Predicts Poor Prognosis in Non-small Cell Lung Cancer

Background: METTL3 accelerates m6A modification to influence cancer progression including non-small cell lung cancer (NSCLC). To illustrate the role and underlying mechanism of METTL3 mediated miR-196a upregulation in NSCLC. Method: The global level of m6A modification was detected by qPCR, western blot and immumohistochemical staining. The TCGA, GEPIA, CPTAC and TIMER databases were used to explore the expression change of METTL3, miR-196a and GAS7 in NSCLC patients. Kaplan-Meier analysis was performed to analyze the prognostic value of miR-196a. NSCLC cells overexpressed or knockdown miR-196a were constructed and used for CCK8, colony formation assay, western blot and immunofluorescence in vitro. The effect of miR-196a on tumor growth was investigated in vivo. Result: We found that METTL3 mediated miR-196a were notably enhancive in NSCLC tissues and in NSCLC cells, which is markedly positively related with the serious TNM stage, the large tumor size, the distant metastasis, and the poor prognosis in patients of NSCLC. Further investigation showed that up-regulated miR-196a promoted cell viability and cell autophagy, while down-regulation of miR-196a revealed opposite results in H1299 and A549 cells. In terms of mechanism, we found that miR-196a interacted with GAS7. In addition, GAS7 expression in NSCLC patients may be positively related with the infiltration of immune cell subsets in tumor microenvironment (TME). Conclusion: The axis of METTL3-miR-196a-GAS7 might be a target for molecular targeted therapy, a potential and novel diagnostic marker for NSCLC patients.

METTL14 contributes to acute lung injury by stabilizing NLRP3 expression in an IGF2BP2-dependent manner

Acute lung injury (ALI) as well as its more severe form, acute respiratory distress syndrome (ARDS), frequently leads to an uncontrolled inflammatory response. N6-methyladenosine (m6A) modification was associated with the progression of several inflammatory diseases. However, the role of methyltransferase-like 14 (METTL14)-mediated m6A methylation in ALI/ARDS remains unclear. Here, we reported an increase in overall expression levels of m6A and METTL14 in circulating monocyte-derived macrophages recruited to the lung following ALI, which is correlated with the severity of lung injury. We further demonstrated the critical function of METTL14 in activating NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome in vitro and in mouse models of ALI/ARDS, and validated NLRP3 as the downstream target of METTL14 by the m6A RNA immunoprecipitation (MeRIP) and RIP assays. Mechanistically, METTL14-methylated NLRP3 transcripts were subsequently recognized by insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2), an m6A reader, which stabilized NLRP3 mRNA. Furthermore, we observed that IGF2BP2 knockdown diminished LPS-induced ALI in mice by downregulating NLRP3 expression. In summation, our study revealed that the molecular mechanism underlying the pathogenesis of ALI/ARDS involves METTL14-mediated activation of NLRP3 inflammasome in an IGF2BP2 dependent manner, thereby demonstrating the potential of METTL14 and IGF2BP2 as promising biomarkers and therapeutic targets for ALI/ARDS treatment.

METTL3-dependent N6-methyladenosine modification is involved in berberine-mediated neuroprotection in ischemic stroke by enhancing the stability of NEAT1 in astrocytes

Ischemic stroke (IS) is one of the principal causes of disability and death worldwide. Berberine (BBR), derived from the traditional Chinese herbal medicine Huang Lian, has been reported to inhibit the progression of stroke, but the specific mechanism whereby BBR modulates the progression of ischemic stroke remains unclear. N6-methyladenosine (m6A) modification is the most typical epigenetic modification of mRNA post-transcriptional modifications, among which METTL3 is the most common methylation transferase. During the study, the middle cerebral artery occlusion/reperfusion (MCAO/R) was established in mice, and the mice primary astrocytes and neurons induced by oxygen-glucose deprivation/reoxygenation (OGD/R) was simulated in vitro. Level of LncNEAT1, miR-377-3p was detected via RT-qPCR. The levels of Nampt and METTL3 were measured by Western blot. CCK8 and LDH assay was performed to detect cell viability. Here, we found that berberine alleviates MCAO/R-induced ischemic injury and up-regulates the expression of Nampt in astrocytes, miR-377-3p inhibits the expression of Nampt in astrocytes after OGD/R, thus promoting neuronal injury. NEAT1 binds to miR-377-3p in OGD/R astrocytes and plays a neuronal protective role as a ceRNA. METTL3 can enhance NEAT1 stability in OGD/R astrocytes by modulating m6A modification of NEAT1. Taken together, our results demonstrate that berberine exerts neuroprotective effects via the m6A methyltransferase METTL3, which regulates the NEAT1/miR-377-3p/Nampt axis in mouse astrocytes to ameliorate cerebral ischemia/reperfusion (I/R) injury.

Integrative Analysis of N6-methyladenosine RNA modifications related genes and their Influences on Immunoreaction or fibrosis in myocardial infarction

Increasing studies have shown that N6-methyladenosine (m6A) modification plays an important role in cardiovascular diseases. In this study, we systematically investigated the regulatory mode of m6A genes in myocardial infarction (MI) by combining bioinformatics analysis of clinical samples with animal experiments. We utilized gene expression data of clinical samples from public databases to examine the expression of m6A genes in heart tissues and found a large difference between the healthy control group and MI group. Subsequently, we established an MI diagnosis model based on the differentially expressed m6A genes using the random forest method. Next, unsupervised clustering method was used to classify all MI samples into two clusters, and the differences in immune infiltration and gene expression between different clusters were compared. We found LRPPRC to be the predominant gene in m6A clustering, and it was negatively correlated with immunoreaction. Through GO enrichment analysis, we found that most differentially expressed genes between the two clusters were profibrotic. By means of WGCNA, we inferred that GJA4 might be a core molecule in the m6A regulatory network of MI. This study demonstrates that m6A regulators probably affects the immune-inflammatory response and fibrosis to regulate the process of MI, which provides a potential therapeutic target.

Epigenetic modification of m6A methylation: Regulatory factors, functions and mechanism in inflammatory bowel disease

Although the exact cause of inflammatory bowel disease (IBD) is still unknown, there is a lot of evidence to support the notion that it results from a combination of environmental factors, immune system issues, gut microbial changes, and genetic susceptibility. In recent years, the role of epigenetics in the pathogenesis of IBD has drawn increasing attention. The regulation of IBD-related immunity, the preservation of the intestinal epithelial barrier, and autophagy are all significantly influenced by epigenetic factors. The most extensive epigenetic methylation modification of mammalian mRNA among them is N6-methyladenosine (m6A). It summarizes the general structure and function of the m6A regulating factors, as well as their complex effects on IBD by regulating the intestinal mucous barrier, intestine mucosal immunity, epidermal cell death, and intestinal microorganisms.This paper provides key insights for the future identification of potential new targets for the diagnosis and treatment of IBD.

LAMA3 Promotes Tumorigenesis of Oral Squamous Cell Carcinoma by METTL3-Mediated N6-Methyladenosine Modification

Laminin subunit alpha 3 (LAMA3) is a cancer regulator. However, its effects and regulatory pathways in oral squamous cell carcinoma (OSCC) progression remain unknown. This research aimed to determine the influence of LAMA3 regulation via methyltransferase-like 3 (METTL3) on OSCC progression. Using quantitative real-time polymerase chain reaction and bioinformatics analysis, the expression levels of LAMA3 and METTL3 in OSCC tissues were examined. The functional roles of LAMA3 and METTL3 were analyzed using cell functional experiments. Using methylated RNA immunoprecipitation and mRNA stability assays, LAMA3 and METTL3 regulation was investigated. In OSCC tissues, LAMA3 was upregulated. LAMA3 inhibition hampered OSCC cell proliferation, invasion, and migration while its overexpression facilitated OSCC cell progression. METTL3 serves as a crucial upstream regulator of LAMA3 in OSCC and upregulates LAMA3 expression via an m6A-dependent mechanism. The low METTL3 expression partially restored the enhanced malignant phenotype induced by LAMA3 overexpression. Our findings indicate that METTL3 and LAMA3 act as pro-oncogenic factors in OSCC, with METTL3 promoting OSCC malignancy via m6A modification-dependent stabilization of LAMA3 transcripts, representing a novel regulatory mechanism in OSCC.

METTL3 boosts mitochondrial fission and induces cardiac fibrosis after ischemia/reperfusion injury

METTL3, an RNA methyltransferase enzyme, exerts therapeutic effects on various cardiovascular diseases. Myocardial ischemia-reperfusion injury (MIRI) and subsequently cardiac fibrosis is linked to acute cardiomyocyte death or dysfunction induced by mitochondrial damage, particularly mitochondrial fission. Our research aims to elucidate the potential mechanisms underlying the therapeutic actions of METTL3 in MIRI, with focus on mitochondrial fission. When compared with Mettl3flox mice subjected to MIRI, Mettl3 cardiomyocyte knockout (Mettl3Cko) mice have reduced infarct size, decreased serum levels of myocardial injury-related factors, limited cardiac fibrosis, and preserved myocardial ultrastructure and contractile/relaxation capacity. The cardioprotective actions of Mettl3 knockout were associated with reduced inflammatory responses, decreased myocardial neutrophil infiltration, and suppression of cardiomyocyte death. Through signaling pathway validation experiments and assays in cultured HL-1 cardiomyocytes exposed to hypoxia/reoxygenation, we confirmed that Mettl3 deficiency interfere with DNA-PKcs phosphorylation, thereby blocking the downstream activation of Fis1 and preventing pathological mitochondrial fission. In conclusion, this study confirms that inhibition of METTL3 can alleviate myocardial cardiac fibrosis inflammation and prevent cardiomyocyte death under reperfusion injury conditions by disrupting DNA-PKcs/Fis1-dependent mitochondrial fission, ultimately improving cardiac function. These findings suggest new approaches for clinical intervention in patients with MIRI.

lncRNA POU6F2-AS1 Regulated by KIAA1429 Contributes to Colorectal Cancer Progression in an m6A Modification Manner

Long non-coding RNAs (lncRNAs) are participated in tumourigenesis, including colorectal cancer (CRC). However, the effects and mechanisms of lncRNA POU6F2-AS1 in CRC have not been investigated. KIAA1429 act as a member of N6-methyladenosine (m6A) modification, has been knew as an oncogenic factor in various cancer containing CRC. We focus to investigate the regulation effect of lncRNA POU6F2-AS1, and the mechanism among lncRNA POU6F2-AS1 and KIAA1429 in CRC. The lncRNA POU6F2-AS1 and KIAA1429 levels in CRC tissue samples as well as cells were clarified by qRT-PCR, and their relationship was predicted by bioinformatics, MeRIP and Pearson analysis. Cell survival, migration and invasion were analyzed via EdU, wound healing and Transwell assays after lncRNA POU6F2-AS1 was down-regulated and KIAA1429 was up-regulated. LncRNA POU6F2-AS1 and KIAA1429 were enriched in CRC tissue samples. LncRNA POU6F2-AS1 silencing suppressed CRC cell survival, migration, and invasion, and KIAA1429 overexpression facilitated CRC cell malignancy. KIAA1429 promoted lncRNA POU6F2-AS1 expression via m6A modification. Furthermore, KIAA1429 upregulation reversed the inhibitory effect of lncRNA POU6F2-AS1 interference on the malignant behavior of CRC cells. lncRNA POU6F2-AS1 was modulated by KIAA1429 in the form of m6A modification to regulate the malignant phenotype of CRC, which may provide new insights into the potential application of KIAA1429-m6A-lncRNA POU6F2-AS1-based CRC therapy.

Exploring the Multifaceted Biologically Relevant Roles of circRNAs: From Regulation, Translation to Biomarkers

CircRNAs are a category of regulatory RNAs that have garnered significant attention in the field of regulatory RNA research due to their structural stability and tissue-specific expression. Their circular configuration, formed via back-splicing, results in a covalently closed structure that exhibits greater resistance to exonucleases compared to linear RNAs. The distinctive regulation of circRNAs is closely associated with several physiological processes, as well as the advancement of pathophysiological processes in several human diseases. Despite a good understanding of the biogenesis of circular RNA, details of their biological roles are still being explored. With the steady rise in the number of investigations being carried out regarding the involvement of circRNAs in various regulatory pathways, understanding the biological and clinical relevance of circRNA-mediated regulation has become challenging. Given the vast landscape of circRNA research in the development of the heart and vasculature, we evaluated cardiovascular system research as a model to critically review the state-of-the-art understanding of the biologically relevant functions of circRNAs. We conclude the review with a discussion of the limitations of current functional studies and provide potential solutions by which these limitations can be addressed to identify and validate the meaningful and impactful functions of circRNAs in different physiological processes and diseases.

NAT10 Is Involved in Cardiac Remodeling Through ac4C-Mediated Transcriptomic Regulation

BACKGROUND

Heart failure, characterized by cardiac remodeling, is associated with abnormal epigenetic processes and aberrant gene expression. Here, we aimed to elucidate the effects and mechanisms of NAT10 (N-acetyltransferase 10)-mediated N4-acetylcytidine (ac4C) acetylation during cardiac remodeling.

METHODS

NAT10 and ac4C expression were detected in both human and mouse subjects with cardiac remodeling through multiple assays. Subsequently, acetylated RNA immunoprecipitation and sequencing, thiol-linked alkylation for the metabolic sequencing of RNA (SLAM-seq), and ribosome sequencing (Ribo-seq) were employed to elucidate the role of ac4C-modified posttranscriptional regulation in cardiac remodeling. Additionally, functional experiments involving the overexpression or knockdown of NAT10 were conducted in mice models challenged with Ang II (angiotensin II) and transverse aortic constriction.

RESULTS

NAT10 expression and RNA ac4C levels were increased in in vitro and in vivo cardiac remodeling models, as well as in patients with cardiac hypertrophy. Silencing and inhibiting NAT10 attenuated Ang II-induced cardiomyocyte hypertrophy and cardiofibroblast activation. Next-generation sequencing revealed ac4C changes in both mice and humans with cardiac hypertrophy were associated with changes in global mRNA abundance, stability, and translation efficiency. Mechanistically, NAT10 could enhance the stability and translation efficiency of CD47 and ROCK2 transcripts by upregulating their mRNA ac4C modification, thereby resulting in an increase in their protein expression during cardiac remodeling. Furthermore, the administration of Remodelin, a NAT10 inhibitor, has been shown to prevent cardiac functional impairments in mice subjected to transverse aortic constriction by suppressing cardiac fibrosis, hypertrophy, and inflammatory responses, while also regulating the expression levels of CD47 and ROCK2 (Rho associated coiled-coil containing protein kinase 2).

CONCLUSIONS

Therefore, our data suggest that modulating epitranscriptomic processes, such as ac4C acetylation through NAT10, may be a promising therapeutic target against cardiac remodeling.

The role of N-methyladenosine modification in acute and chronic kidney diseases

N6-methyladenosine (m6A) modification is a kind of RNA modification in which methylation occurs at the sixth N position in adenosine in RNA, which can occur in various RNAs such as mRNAs, lncRNAs and miRNAs. This is one of the most prominent and frequent posttranscriptional modifications within organisms and has been shown to function dynamically and reversibly in a variety of ways, including splicing, export, attenuation and translation initiation efficiency to regulate RNA expression. There are three main enzymes associated with m6A modification: writers, readers and erasers. Increasing evidence has shown that m6A modification is associated with the onset and development of kidney disease. In this article, we address the important physiological and pathological roles of m6A modification in kidney diseases (uremia, ischemia-reperfusion kidney injury, drug-induced kidney injury, and diabetic nephropathy) and its molecular mechanisms to provide reference for the diagnosis and clinical management of kidney diseases.

Cancer-associated fibroblasts secret extracellular vesicles to support cell proliferation and epithelial-mesenchymal transition in laryngeal squamous cell carcinoma

As the critical components of tumor microenvironment, cancer-associated fibroblasts (CAFs) support the development of various type of cancers, including laryngeal squamous cell carcinoma (LSCC), but the detailed molecular mechanisms by which cancer-associated fibroblasts interact with LSCC cells to facilitate its progression have not been fully uncovered. In the present study, by analyzing the contents from normal fibroblasts (NFs) and cancer-associated fibroblasts-derived extracellular vesicles (EVs) with Real-Time qPCR analysis, we found that the tumor-initiating LncRNA TUC338 was significantly upregulated in the cancer-associated fibroblasts-derived extracellular vesicles, compared to the normal fibroblasts-secreted extracellular vesicles. Further experiments confirmed that cancer-associated fibroblasts-derived extracellular vesicles promoted cell proliferation, colony formation abilities, epithelial-mesenchymal transition (EMT) and tumorigenesis of LSCC cells via delivering LncRNA TUC338. The mechanical experiments verified that LncRNA TUC338 was stabilized by METTL3/YTHDF1-mediated N6-methyladenosine (m6A) modifications, and elevated LncRNA TUC338 sponged miR-8485 to upregulate chromobox homolog 2 (CBX2) in LSCC cells in a competing endogenous RNA mechanisms-dependent manner. Moreover, our rescue experiments evidenced that cancer-associated fibroblasts-derived LncRNA TUC338-containing extracellular vesicles-induced supportive effects in LSCC aggressiveness were all abrogated by overexpressing miR-8485 and silencing CBX2. Collectively, this study is the first to identify a novel m6A/LncRNA TUC338/miR-8485/CBX2 axis in CAFs-EVs-mediated LSCC development, and to show its potential as a diagnostic biomarker for LSCC.

N6-methyladenosine modification: Regulatory mechanisms and therapeutic potential in sepsis

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection and is characterized by multiple biological and clinical features. N6-methyladenosine (m6A) modification is the most common type of RNA modifications in eukaryotes and plays an important regulatory role in various biological processes. Recently, m6A modification has been found to be involved in the regulation of immune responses in sepsis. In addition, several studies have shown that m6A modification is involved in sepsis-induced multiple organ dysfunctions, including cardiovascular dysfunction, acute lung injury (ALI), acute kidney injury (AKI) and etc. Considering the complex pathogenesis of sepsis and the lack of specific therapeutic drugs, m6A modification may be the important bond in the pathophysiological process of sepsis and even therapeutic targets. This review systematically highlights the recent advances regarding the roles of m6A modification in sepsis and sheds light on their use as treatment targets for sepsis.

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.

N4-acetylcytidine-dependent GLMP mRNA stabilization by NAT10 promotes head and neck squamous cell carcinoma metastasis and remodels tumor microenvironment through MAPK/ERK signaling pathway

N4-acetylcytidine (ac4C) is a post-transcriptional RNA modification that regulates in various important biological processes. However, its role in human cancer, especially lymph node metastasis, remains largely unknown. Here, we demonstrated N-Acetyltransferase 10 (NAT10), as the only known "writer" of ac4C mRNA modification, was highly expressed in head and neck squamous cell carcinoma (HNSCC) patients with lymph node metastasis. High NAT10 levels in the lymph nodes of patients with HNSCC patients are a predictor of poor overall survival. Moreover, we found that high expression of NAT10 was positively upregulated by Nuclear Respiratory Factor 1 (NRF1) transcription factor. Gain- and loss-of-function experiments displayed that NAT10 promoted cell metastasis in mice. Mechanistically, NAT10 induced ac4C modification of Glycosylated Lysosomal Membrane Protein (GLMP) and stabilized its mRNA, which triggered the activation of the MAPK/ERK signaling pathway. Finally, the NAT10-specific inhibitor, remodelin, could inhibit HNSCC tumorigenesis in a 4-Nitroquinoline 1-oxide (4NQO)-induced murine tumor model and remodel the tumor microenvironment, including angiogenesis, CD8+ T cells and Treg recruitment. These results demonstrate that NAT10 promotes lymph node metastasis in HNSCC via ac4C-dependent stabilization of the GLMP transcript, providing a potential epitranscriptomic-targeted therapeutic strategy for HNSCC.

The potential role of RNA modification in skin diseases, as well as the recent advances in its detection methods and therapeutic agents

RNA modification is considered as an epigenetic modification that plays an indispensable role in biological processes such as gene expression and genome editing without altering nucleotide sequence, but the molecular mechanism of RNA modification has not been discussed systematically in the development of skin diseases. This article mainly presents the whole picture of theoretical achievements on the potential role of RNA modification in dermatology. Furthermore, this article summarizes the latest advances in clinical practice related with RNA modification, including its detection methods and drug development. Based on this comprehensive review, we aim to illustrate the current blind spots and future directions of RNA modification, which may provide new insights for researchers in this field.

Mettl3 induced miR-338-3p expression in dendritic cells promotes antigen-specific Th17 cell response via regulation of Dusp16

Pathogenic Th17 cells are critical drivers of multiple autoimmune diseases, including uveitis and its animal model, experimental autoimmune uveitis (EAU). However, how innate immune signals modulate pathogenic Th17 responses remains largely unknown. Here, we showed that miR-338-3p endowed dendritic cells (DCs) with an increased ability to activate interphotoreceptor retinoid-binding protein (IRBP)1-20 -specific Th17 cells by promoting the production of IL-6, IL-1β, and IL-23. In vivo administration of LV-miR-338-infected DCs promoted pathogenic Th17 responses and exacerbated EAU development. Mechanistically, dual-specificity phosphatase 16 (Dusp16) was a molecular target of miR-338-3p. miR-338-3p repressed Dusp16 and therefore strengthened the mitogen-activated protein kinase (MAPK) p38 signaling, resulting in increased production of Th17-polarizing cytokines and subsequent pathogenic Th17 responses. In addition, methyltransferase like 3 (Mettl3), a key m6A methyltransferase, mediated the upregulation of miR-338-3p in activated DCs. Together, our findings identify a vital role for Mettl3/miR-338-3p/Dusp16/p38 signaling in DCs-driven pathogenic Th17 responses and suggest a potential therapeutic avenue for uveitis and other Th17 cell-related autoimmune disorders.

Shining a spotlight on m6A and the vital role of RNA modification in endometrial cancer: a review

RNA modifications are mostly dynamically reversible post-transcriptional modifications, of which m6A is the most prevalent in eukaryotic mRNAs. A growing number of studies indicate that RNA modification can finely tune gene expression and modulate RNA metabolic homeostasis, which in turn affects the self-renewal, proliferation, apoptosis, migration, and invasion of tumor cells. Endometrial carcinoma (EC) is the most common gynecologic tumor in developed countries. Although it can be diagnosed early in the onset and have a preferable prognosis, some cases might develop and become metastatic or recurrent, with a worse prognosis. Fortunately, immunotherapy and targeted therapy are promising methods of treating endometrial cancer patients. Gene modifications may also contribute to these treatments, as is especially the case with recent developments of new targeted therapeutic genes and diagnostic biomarkers for EC, even though current findings on the relationship between RNA modification and EC are still very limited, especially m6A. For example, what is the elaborate mechanism by which RNA modification affects EC progression? Taking m6A modification as an example, what is the conversion mode of methylation and demethylation for RNAs, and how to achieve selective recognition of specific RNA? Understanding how they cope with various stimuli as part of in vivo and in vitro biological development, disease or tumor occurrence and development, and other processes is valuable and RNA modifications provide a distinctive insight into genetic information. The roles of these processes in coping with various stimuli, biological development, disease, or tumor development in vivo and in vitro are self-evident and may become a new direction for cancer in the future. In this review, we summarize the category, characteristics, and therapeutic precis of RNA modification, m6A in particular, with the purpose of seeking the systematic regulation axis related to RNA modification to provide a better solution for the treatment of EC.