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TET2 promotes monocyte inflammatory activation in asthma via ALKBH5-m6A regulation and PI3K signaling: evidence from m6A-SNP and single-cell analyses.

Asthma is a complex inflammatory airway disease with strong genetic determinants, yet the functional relevance of most asthma-associated non-coding variants remains unclear. Emerging evidence suggests that N6-methyladenosine (m6A) modification may serve as a critical epitranscriptomic link between genetic variation and immune regulation. In this study, we aimed to systematically identify functionally relevant m6A-regulated genes in asthma by integrating large-scale GWAS data, m6A-SNP annotations, and single-cell transcriptomic analyses, and to investigate their roles in monocyte-driven airway inflammation. We identified TET2 as a key m6A-regulated gene associated with both asthma and lung function, which was selectively upregulated in monocytes during asthma and accompanied by activation of inflammatory and PI3K signaling pathways. Mechanistic experiments further demonstrated that inflammatory stimulation induced ALKBH5 expression, reduced m6A modification of TET2 mRNA, and increased TET2 protein levels, thereby promoting PI3K/AKT signaling and pro-inflammatory cytokine production, whereas inhibition of TET2 or ALKBH5 attenuated these effects. Collectively, these findings demonstrate that ALKBH5-mediated m6A regulation of TET2 enhances PI3K/AKT signaling in monocytes, thereby promoting inflammatory responses in asthma. Our study establishes TET2 as a key m6A-regulated gene linking genetic susceptibility to monocyte-driven inflammation, and highlights the ALKBH5-m6A-TET2 axis as a potential therapeutic target for modulating aberrant immune responses in asthma.

Humans

m6A regulator-based molecular classification and hub genes associated with immune infiltration characteristics and clinical outcomes in diffuse gliomas.

BACKGROUND: m6A methylation modification is a new regulatory mechanism involved in tumorigenesis and tumor-immunity interaction. However, its impact on glioma immune microenvironment and clinical outcomes remains unclear. METHODS: Comprehensive expression profiles of 18 m6A regulators were used to identify molecular subtypes exhibiting distinct m6A modification patterns in 1673 glioma samples sourced from public datasets. A multi-genes signature was constructed for predicting clinical outcomes and response to immunotherapy in glioma patients. Immunohistochemistry and cellular experiments were performed for validation. RESULTS: Two m6A subtypes of gliomas were identified. The m6A-low-risk subtype was characterized by paucity of immune infiltrates; While the m6A-high-risk subtype had higher abundances of multiple immune cells including lymphocyte and macrophage as well as increased expression of PD-L1, corresponding to an immunosuppressive phenotype. The m6A-high-risk subtype had poorer survival than the m6A-low-risk subtype in both the glioblastoma and lower grade gliomas cohorts. Eight m6A-related hub genes of high prognostic significances were identified and selected for developing a scoring signature termed as m6Ascore. Elevated m6Ascore indicated worse survival for glioma patients under standard care, but showed enhanced response to immunotherapy. Moreover, we demonstrated that overexpression of FTO, a m6A demethylase, inhibited the expressions of m6A-related hub genes (PTX3, SPAG4), impaired glioma cell viability and reduced macrophage chemotaxis. CONCLUSION: This work develops an immune- and clinical-relevant m6A subtyping and a scoring model, which enhances our understanding of the role of m6A modification in regulating immune infiltration microenvironment in gliomas and helps to identify patients who are more likely to benefit from immunotherapy.

Humans

A multifaceted investigation into the impact of m6A methylation-related genes on pancreatic cancer, integrating insights from various databases and foundational experimental research.

BACKGROUND: Despite advances in surgical techniques, immunotherapy, the mortality rate associated with pancreatic cancer (PC) has been on the rise in recent years. Understanding the importance of RNA N6-methyladenosine (m6A) in PC is critical for prognosis, tumor microenvironment, and immunotherapy efficacy. The study aims to identify m6A methylation regulators that play an important role in the development and progression of PC by mining databases. The effect of insulin-like growth factor-binding protein 3 (IGFBP3) on pancreatic tumors was explored, and the related mechanisms were explored. METHODS: We analyzed the expression of m6A regulators in PC by digging deeper into the datasets of The Cancer Genome Atlas and Gene Expression Omnibus (GEO) databases, and analyzed its relationship with the prognosis of patients with PC, looking for m6A methylation regulators that play an important role in the development and progression of PC. Reuse the ConsensusClusterPlus package, Cox analysis, and unsupervised clustering to delineate three distinct m6A clusters - designated as m6A cluster A, m6A cluster B, and m6A cluster C single-sample gene set enrichment analysis, gene set variation analysis, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses evaluated the different pathway roles of these clusters in the development and progression of PC. Finally, the cell lines with IGFBP3 overexpression and knockdown were constructed by lentivirus transfection, the transfection effect was identified by WB, and the effects of IGFBP3 overexpression/knockdown on the survival and growth of PC cell lines were verified by cell cloning experiments and cell counting kit-8 experiments, and the possible related pathways were explored by KEGG. RESULTS: Most m6A regulatory factors are highly expressed in PC, and their high expression is negatively correlated with the prognosis of patients with PC. Furthermore, m6A regulatory factors may influence the occurrence and development of PC through metabolic pathways, stroma activation pathways, immune regulatory processes, and the immune microenvironment. Finally, the overexpression of IGFBP3 promoted the growth of PC cells, and vice versa. CONCLUSIONS: Most m6A regulatory factors are differentially expressed in PC and are associated with the prognosis of patients with PC, potentially influencing the occurrence and development of PC through pathways such as the immune microenvironment. The overexpression of IGFBP3 can promote the growth of PC cells and vice versa.

IGFBP3

Integrated multi-omics identification of m6A-SNP-related diagnostic biomarkers in amyotrophic lateral sclerosis.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) lacks reliable and minimally invasive biomarkers for early diagnosis. m6A-associated single-nucleotide polymorphisms (m6A-SNPs) may influence RNA methylation and gene expression, offering opportunities to identify clinically relevant diagnostic markers. METHODS: We integrated eQTLGen cis-eQTL data, RMVar m6A-SNP annotations, and ALS transcriptomic datasets to identify m6A-SNP-related genes. Random Forest and LASSO regression were combined to screen robust diagnostic markers. A nomogram was constructed and validated using independent cohorts. Immune infiltration, predicted m6A modification sites, and potential RBP-SNP interactions were assessed. Peripheral blood samples from ALS patients were used for exploratory validation of gene expression and global m6A levels. RESULTS: We identified 109 ALS-associated m6A-SNP-related genes with cis-eQTL signals and narrowed these to seven candidate diagnostic markers (TMED5, OXR1, BRI3, FEM1C, SUZ12, EIF2AK4, and TJAP1). The seven-gene model outperformed the individual markers in the training cohort and retained moderate discrimination in the independent validation cohort. ALS samples showed differences in inferred immune-cell composition, including monocytes, neutrophils, and T-cell subsets. The selected SNP loci were located near predicted m6A sites and annotated RBP-binding regions. Exploratory clinical validation showed significant upregulation of FEM1C and SUZ12 at both mRNA and protein levels, accompanied by reduced global m6A modification. CONCLUSIONS: Through multi-omics integration and exploratory clinical validation, this study identifies m6A-SNP-related candidate markers associated with ALS. The findings support further evaluation of m6A-related signatures for ALS discrimination and molecular characterization, while larger independent cohorts and additional calibration are required before clinical application.

Humans

m6A RNA methylation modulates IFN-γ-stimulated intestinal epithelial cell-intrinsic antiparasitic defense.

N6-methyladenosine (m6A) RNA methylation is one of the most prevalent reversible post-transcriptional RNA modifications and has been recognized as a crucial regulator of host immune responses. Intestinal epithelial cells (IECs) constitute an important component of gastrointestinal mucosal immunity. Interferons (IFNs) play a central role in maintaining intestinal homeostasis, and m6A methylation status influences IFN-mediated cell-intrinsic defense. In this study, we investigated the potential role of m6A RNA modifications in IFN-γ-stimulated IEC-intrinsic defense. We observed significant alterations in the topology of the m6A mRNA methylome in murine IECs following IFN-γ stimulation. A subset of IFN-γ-stimulated immune gene transcripts exhibited increased m6A RNA methylation, including several members of the immunity-related GTPase family M (IRGM) genes. In addition, IFN-γ-responsive long non-coding RNAs may modulate the m6A methylation levels of multiple IFN-γ-stimulated immune transcripts. Enhanced m6A methylation of the Irgm2/3 transcripts was associated with strengthened cell-intrinsic defense against infection by the protozoan parasite Cryptosporidium. Notably, Cryptosporidium infection altered the host m6A mRNA methylome in IECs, thereby counteracting the IFN-γ-mediated defense response. Although the RNA levels of Irgm2/3 genes were upregulated, their m6A RNA methylation levels and protein expression were reduced in infected cells. This effect was associated with host delivery of dsRNAs derived from Cryptosporidium parvum virus 1, a virus harbored in the parasite. Collectively, our findings suggest that m6A methylation of RNA transcripts enhances IFN-γ-mediated IEC-intrinsic antiparasitic defense, while Cryptosporidium has evolved mechanisms to evade this response by suppressing m6A RNA methylation of IFN-γ-stimulated immune genes.

Animals

Chronic nitric oxide mediates dual-layer gene regulation through mRNA m6A positional remodeling and parallel transcriptional reprogramming.

Nitric oxide (NO) is a pleiotropic free radical that functions as a master regulator of gene expression, and its sustained production within the tumor microenvironment reshapes the epitranscriptomic state of cancer cells. We previously demonstrated that NO inhibits the m6A mRNA demethylases FTO and ALKBH5 through dinitrosyliron complex formation while leaving the methyltransferase METTL3 intact, a demethylase-specific perturbation that increases global m6A on mRNA. Here, integrating m6A-RIP-seq and RNA-seq from triple-negative breast cancer cells, we show that chronic NO does not produce the uniform hypermethylation anticipated from demethylase inhibition. Instead, it redistributes m6A on mRNA, enriching the 5'UTR and coding sequence while depleting the 3'UTR and departing from the canonical stop-codon and 3'UTR topology. We found that the position of m6A, rather than its intensity or mere presence, shapes the outcome, in part by determining which reader protein is predicted to recognize it. In parallel, NO drives a canonical NF-κB and inflammatory transcriptional program. The transcriptional program is independent of the m6A methylome in both which genes respond and how strongly they respond, ruling out a linear methylome-to-transcriptome cascade; even so, m6A position remains associated with the direction of change among responding transcripts. The 3'UTR is the primary site of m6A loss and shows a suggestive computational link to miRNA-mediated regulation. Sense-antisense coordination reinforces the transcriptional response without bridging the two programs. These findings demonstrate that NO not only increases m6A abundance, but it also rewrites the m6A positional code, establishing spatial reprogramming of the epitranscriptome as a previously unrecognized mode of gene regulation.

RNA Methylation

Spatial Mapping and Interactome Profiling of m6A-Modified R-Loops via Chemically Inducible Split-APEX2 Proximity Labeling.

m6A-Modified R-loops (m6A-R-loops) play crucial roles in epigenetic regulation and genome stability, yet resolving their spatial distribution and protein interactomes in live cells remains challenging. To address this, we developed m6A-R-loop proximity labeling (m6A-RLPL), a chemically inducible split-APEX2 proximity labeling technology integrating dual-target recognition using the RNA-DNA hybrid binding domain of RNase H1 for R-loop targeting and m6A reader protein's YTH domain for m6A recognition, coupled with an abscisic acid (ABA)-inducible dimerization system for signal amplification. This technology revealed host m6A-R-loops enriched with nucleoli under normal conditions. When applied to herpes simplex virus (HSV) infection, it further demonstrated viral m6A-R-loops undergoing dramatic accumulation within phase-separated granules in replication compartments during late-stage infection. Proximity proteomics identified ZC3H4 and CCDC124 as essential regulators maintaining these structures, which serve as transcription sites for HSV late genes, with disruption selectively impairing viral transcription. m6A-RLPL establishes a generalizable approach for spatially resolved profiling of m6A-R-loop interactomes and organizational dynamics in living systems.

Humans

Epitranscriptomic reprogramming in response to low CO2 stress and m6A engineering to enhance biomass production in Nannochloropsis oceanica.

N6-adenine methylation (m6A) as an epitranscriptomic mark is the most abundant modification in eukaryotic RNA and plays a dynamically regulated role. However, m6A dynamics, deposition and engineering in microalgae remain largely unknown. Here, in Nannochloropsis oceanica, the dynamic alterations and reprogramming in m6A RNA modifications after the shift from high to low CO2 conditions were first investigated using methylated RNA immunoprecipitation sequencing. The m6A peaks in N. oceanica were mainly enriched in 3'UTR. A positive association between m6A abundance and mRNA transcription of CO2-responsive genes was observed; moreover, N. oceanica cells adopted versatile strategies in a dynamic reprogramming of m6A in response to low CO2 stress. Secondly, knockout of two putative m6A methylases including NoMTA (NO04G02990) and NoMTB (NO07G02450) by genome editing induced methylation reprogramming, which was associated with expression changes of low-CO2 responsive genes such as carbon/nitrogen metabolism, and photorespiration genes that underlie reductions in growth and biomass. Lastly, m6A modification reprogramming was first engineered to increase low-CO2 stress tolerance and biomass productivity by the CRISPR/dCas13 system combined with MTA and NoMTB under low CO2 in N. oceanica. Therefore, these strides would pave the way for microalgal epigenetics and future industrial applications.

Microalgae

Human m6A demethylase FTO modulates the flowering time of tomato plants under low-temperature stress.

N6-methyladenosine (m6A) RNA modification plays an important role in plant development and environmental stress responses. However, whether m6A demethylation modulates flowering under low-temperature (LT) stress in tomatoes remains unclear. Here, we investigated whether ectopic expression of FTO, a well-characterized human m6A demethylase, influences flowering and post-transcriptional behaviour in tomato (Solanum lycopersicum) under LT conditions. Flowering of transgenic tomato plants expressing FTO was analyzed under LT and normal conditions (NC), and the impacts of FTO on transcripts-specific m6A level, mRNA stability and splicing efficiency of flowering-related genes were evaluated using RT-qPCR, LC-MS/MS, m6A-IP-qPCR, and RNA decay and splicing analyses. FTO-expressing plants exhibited accelerated flowering specifically under LT, whereas no significant differences were observed under normal growth conditions. This phenotype was accompanied by increased expression of positive floral regulators (SlMC, SlFCA, and SlJ2) and decreased expression of negative regulators (SlSVP, SlSP, and SlTMF) under LT conditions. Notably, these expression changes were associated with altered mRNA stability, with positive regulators showing increased stability and negative regulators showing reduced stability under LT conditions. m6A-IP-qPCR analysis indicated reduced m6A enrichment in these selected transcripts in FTO-expressing plants. In addition to effects on mRNA stability, FTO expression was associated with changes in the splicing efficiency of SlMC transcripts. Collectively, our findings indicate that human FTO functions as an mRNA m6A demethylase in tomatoes and is associated with altered RNA regulatory processes under LT conditions. These findings suggest that m6A-mediated post-transcriptional regulation contributes to stress-induced flowering plasticity under LT conditions, rather than direct activation of canonical flowering pathways.

Abiotic stress

METTL14-mediated m6A modification of CCNE1 accelerates progression of myelodysplastic syndromes via MAPK-ERK and PI3K-AKT signaling pathways.

BACKGROUND: N6-methyladenosine (m6A) is the most common RNA modification and plays a key role in the initiation, progression, and relapse of multiple cancers, including hematologic malignancies. However, the role of m6A and m6A regulatory genes in myelodysplastic syndromes (MDS) remains unclear. This study aims to elucidate the function and molecular mechanism of methyltransferase METTL14 in MDS. METHODS: RT-qPCR was used to assess the expression of multiple m6A regulators, focusing on METTL14 in MDS patients and cell lines. METTL14 overexpressing and knockdown cell lines were established, and CCK-8, EdU, and flow cytometry assays were performed to explore the biological functions of METTL14.Dot blot, MeRIP-Seq, MeRIP-qPCR, RT-qPCR, and Western blot were employed to investigate the underlying molecular mechanism. RESULTS: Dysregulation of multiple m6A regulators was observed in MDS, among which METTL14 was upregulated. Elevated METTL14 expression increases MDS risk and adverse prognosis, emerging as a biomarker for poor prognosis. METTL14 promoted proliferation and cell-cycle progression of MDS cells while inhibiting apoptosis; corresponding changes were observed in cell cycle and apoptosis markers. METTL14 regulated cellular m6A levels. Downstream targets of METTL14 were enriched in cell cycle-related pathways, with CCNE1 identified as a critical target. Knockdown of METTL14, actinomycin D, or S-adenosylhomocysteine treatment reduced CCNE1 mRNA and protein levels. Furthermore, METTL14 activated MAPK-ERK and PI3K-AKT signaling via CCNE1 in an m6A-dependent manner, thereby promoting proliferative MDS cells' capacity. CONCLUSIONS: This study delineates a METTL14/m6A/CCNE1 signaling axis in MDS progression and suggests that METTL14-mediated m6A modification may be a potential therapeutic target for MDS.

Humans

Exploring diagnostic m6A regulators in primary open-angle glaucoma: insight from gene signature and possible mechanisms by which key genes function.

PURPOSE: The purpose of this study was to interrogate the potential role of N6-methyladenosine (m6A) regulators in the process of trabecular meshwork (TM) tissue damage in patients with primary open-angle glaucoma (POAG). METHODS: Firstly, the expression profile of m6A regulators in TM tissues of POAG patients was comprehensively analyzed by bioinformatics analysis; Plasmid transfection and siRNA gene interference were used to enhance or weaken the expression levels of YTHDC2 in human trabecular meshwork cells (HTMCs); Cell migration ability was detected by transwell chamber assay; Immunofluorescence staining assay was used to evaluate the expression of extracellular matrix (ECM) related proteins. RESULTS: Through the analysis of GSE27276 database, 5 m6A regulators with different expression in POAG were screened out. The results of random forest model showed that these 5 m6A regulators exhibited diagnostic potential and were characteristic genes of POAG. All POAG samples could be effectively divided into two groups based on the expression levels of these 5 hub m6A regulators. Immune cell infiltration analysis indicated that the levels of activated CD8+ T cells and regulatory T cells were different in the two subtypes. HTMC oxidative stress cell model and TGF-β2 stimulation cell model were further constructed to verify the expression of the aforementioned hub m6A regulators, and it was found that YTHDC2 mRNA showed the same expression trend in both models. The silencing of YTHDC2 enhanced the migration ability of HTMCs and increased the synthesis ability of ECM. However, when YTHDC2ΔYTH, which lacks the YTH domain, is overexpressed in HTMCs, there is no significant change in the ECM synthesis ability. CONCLUSIONS: The differentially expressed m6A regulators in TM tissues may serve as potential diagnostic biomarkers for POAG. And, in HTMCs, the expression level of YTHDC2 mRNA was changed under oxidative stress or TGF-β2 intervention, and then exerted its regulation on cell migration and ECM synthesis capability through m6A modification, which may be an important part of the disease process of POAG.

Humans

Development of m6A-related prognostic models for survival in lung squamous cell carcinoma with different PD-L1 expression levels.

BACKGROUND: Programmed death-ligand 1 (PD-L1) is widely used in the clinical context of immune checkpoint inhibitor therapy, but its relationship with N6-methyladenosine (m6A) RNA methylation in lung squamous cell carcinoma (LUSC) has not been well defined. This study aimed to investigate the association between PD-L1 messenger RNA (mRNA) expression and m6A regulator expression patterns and to develop exploratory m6A-based prognostic models in LUSC. METHODS: Transcriptome data from 502 patients with LUSC were obtained from The Cancer Genome Atlas (TCGA). Patients were divided into PD-L1 high-expression (PHE) and PD-L1 low-expression (PLE) groups according to the median PD-L1 mRNA level. Differential expression and correlation analyses were performed for 30 m6A regulators. Transcriptome sequencing data from surgical specimens from 28 Asian patients with LUSC were used for expression-pattern comparison. Principal component analysis (PCA), univariate Cox regression, and least absolute shrinkage and selection operator (LASSO)-Cox regression were used to construct prognostic models in the TCGA cohort. RESULTS: In the TCGA cohort, the main differentially expressed m6A regulators between the two PD-L1 groups were YTHDF2 (P<0.001), IGF2BP3 (P<0.001), and YTHDC2 (P<0.001). In the Asian cohort, ALKBH5 (P=0.008) and ZC3H13 (P=0.03) showed significant differences. LASSO-Cox models were constructed for the overall LUSC cohort and for the PHE and PLE subgroups. The overall model included METTL3, HNRNPC, and CBLL1, with a 5-year time-dependent area under the receiver operating characteristic curve (AUC) of 0.579. The 5-year AUCs were 0.742 in the PHE subgroup and 0.652 in the PLE subgroup. The risk score remained independently associated with prognosis in multivariate Cox analysis. CONCLUSIONS: In LUSC, PD-L1 mRNA status was associated with distinct m6A regulator expression profiles. In the TCGA cohort, the PHE subgroup showed higher expression of CBLL1, G3BP1, IGF2BP3, FMR1, and YTHDC2, but lower expression of VIRMA, YTHDF2, and PRRC2A compared with the PLE subgroup. In the National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences (CICAMS) cohort, ALKBH5 and ZC3H13 were more highly expressed in the PHE subgroup. Moreover, m6A-based risk models were associated with survival outcomes, with significant prognostic separation in the overall TCGA cohort and the PHE subgroup, whereas the PLE subgroup showed a weaker survival separation.

Lung squamous cell carcinoma (LUSC)

PRRSV suppresses FTO-dependent m6A demethylation to reprogram STAT signaling and innate immunity.

RNA viruses have evolved diverse strategies to evade host interferon (IFN)-stimulated gene (ISG) defenses; however, how they exploit host epitranscriptomic regulation remains poorly understood. Here, we identify an immune-evasion mechanism in which porcine reproductive and respiratory syndrome virus (PRRSV) targets the m6A demethylase fat mass and obesity-associated protein (FTO) to suppress antiviral signaling. Mechanistically, the viral endoribonuclease nsp11 inhibits STAT5-dependent transcription through the key residues Q96 and S104, thereby reducing FTO expression. Loss of FTO increases m6A modification of STAT2 and STAT3 transcripts, impairing their translation and phosphorylation, thereby attenuating ISG responses. Reduced STAT3 activity further dampens STAT5 signaling, establishing a feed-forward circuit that amplifies suppression of antiviral immunity. Functionally, disruption of this regulatory region (Q96A and S104A) attenuates viral pathogenicity in vivo and restores ISG induction. These mutations also reduce infection-associated inflammatory responses and the accumulation of reactive oxygen species. Together, these findings define a nsp11-STAT5-FTO-STAT2/3 axis that enables PRRSV to reprogram host epitranscriptomic control of innate immunity. Our work reveals a mechanism of epitranscriptomic hijacking and identifies FTO as a key host factor exploited by RNA viruses, highlighting m6A regulation as a potential target for antiviral intervention.IMPORTANCEViruses must overcome host innate immune defenses to establish infection; however, the mechanisms by which they manipulate host RNA regulation remain incompletely understood. In this study, we show that porcine reproductive and respiratory syndrome virus (PRRSV) suppresses interferon responses by targeting the host m6A demethylase FTO through its endoribonuclease nsp11. This process involves the inhibition of STAT5 phosphorylation, which reduces FTO expression and increases m6A modification of key immune regulators, including STAT2 and STAT3, thereby impairing their activation. Disruption of this pathway attenuates viral pathogenicity in vivo and restores antiviral signaling. These results demonstrate that PRRSV can reprogram host epitranscriptomic regulation to modulate innate immunity and suggest that m6A-related pathways may be potential targets for antiviral intervention.

Immunity, Innate

Biomarkers related to m6A and succinic acid metabolism in papillary thyroid carcinoma.

BACKGROUND: Studies have shown that m6A modification is related to the occurrence and development of papillary thyroid carcinoma (PTC). The disorder of succinic acid metabolism is associated with the occurrence and development of various tumors. However, there are few studies based on m6A and succinate metabolism-related genes (SMRGs) in PTC. METHODS: The TCGA-Thyroid carcinoma (THCA), GSE33630, 1159 SMRGs, and 23 m6A regulatory factors were collected from the online databases. Subsequently, the differentially expressed genes (DEGs) were selected between PTC (Tumor) and Normal samples. The overlapping genes among the DEGs, m6A, and SMRGs were applied to screen the biomarkers. Using the 3 machine-learning algorithms, the biomarkers were determined based on the overlapping genes. Next, the biomarkers were evaluated by the ROC curve and expression analysis in TCGA-THCA and GSE33630. Then, the overall survival (OS) differences were compared between the high-and low-expression biomarkers. Finally, immune infiltration analysis, molecular regulatory network, and drug prediction were performed based on the biomarkers. RESULTS: In TCGA-THCA, there were 2800 DEGs between and Normal samples, and then 7 overlapping genes were obtained. Importantly, ADK, TNFRSF10B, CYP7B1, FGFR2, and CPQ were determined as biomarkers with excellent diagnostic efficiency (AUC&#x2009;>&#x2009;0.7). In PTC samples, ADK and TNFRSF10B were high-expressed while CYP7B1, FGFR2, and CPQ were low-expressed. Especially, the high-expression groups of ADK had a better prognosis, while the high-expression groups of CYP7B1, FGFR2, and CPQ had a worse prognosis. Afterward, immune infiltration analysis found that 16 immune cells had infiltration differences between the Tumor and Normal samples. Finally, transcription factor SP1 could regulate CYP7B1 and TNFRSF10B. Moreover, Navitoclax was a potential drug for PTC patients. CONCLUSION: Overall, we described 5 biomarkers associated with adverse prognosis of PTC, including ADK, TNFRSF10B, CYP7B1, FGFR2, and CPQ. All these biomarkers were involved in succinate metabolism and m6A modification of RNA. This set of biomarkers should be explored further for their diagnostic value in PTC. Investigations into the mechanistic role of alteration of succinate metabolism and m6A modification of RNA pathways in the pathophysiology of PTC are warranted.

Humans

m6A RNA modification and its emerging roles in diseases: recent advances and therapeutic implications.

BACKGROUND: In the recent past, insights in post transcriptional regulation of gene expression have profoundly reshaped our understanding of the molecular mechanisms underlying health and disease. This paradigm shift largely stems from the emerging field of epitranscriptomics, which highlights the pivotal role of chemical RNA modifications. While more than 170 distinct chemical modifications on the RNA are known, the m6A modification is the most abundant internal mRNA modification in higher eukaryotic cells, present not only on protein coding transcripts but also on non-coding RNAs, regulated by &#x201c;writers&#x201d;, &#x201c;erasers&#x201d;, and &#x201c;readers&#x201d; that together modulate alternative splicing, nuclear export, translation efficiency, and mRNA stability. MAIN BODY: This review addresses an important gap by presenting a multilayered regulatory framework that catalogs the full repertoire of m6A machinery and uniquely reveals how non-coding RNAs, transcription factors, histone modifications, and chromatin remodelers governs the spatiotemporal specificity of m6A modification. We explore how dysregulation of m6A modification and its regulatory proteins contribute to the development and progression of various diseases such as cardiovascular disease, neurological disorders, cancer, and type 2 diabetes through context-dependent modulation of gene networks. Furthermore, we present an integrative overview of the therapeutic pipeline, tracing the development of small-molecule inhibitors targeting m6A regulators, thus bridging a crucial link between fundamental mechanisms and new therapies. CONCLUSIONS: Overall, this review integrates current findings and emerging insights to provide a comprehensive understanding of m6A biology. By linking upstream regulatory mechanisms with downstream pathological consequences and therapeutic interventions, we highlight the potential of targeting the epitranscriptome for clinical applications.

Humans

m6A-Mediated epitranscriptomic control of mitochondrial dysfunction in neurodegeneration.

Mitochondrial dysfunction is a common pathology of neurodegenerative diseases, which contributes to neuronal vulnerability via excessive oxidative stress, impaired bioenergetics, and dysregulated apoptosis. Emerging studies highlighted the critical role of epitranscriptomic RNA modifications, particularly N6-methyladenosine (m6A), in mitochondrial gene expression regulation and cellular stress responses. m6A modifications are installed by methyltransferases ("writers," METTL3/METTL14), recognized by reader proteins (YTH domain family proteins, IGF2BPs), and removed by demethylases ("erasers," FTO, ALKBH5), collectively orchestrating mRNA splicing, localization, stability, and translation. Recent evidence demonstrates that m6A modifications modulate both nuclear-encoded and mitochondrially encoded transcripts and regulate key mitochondrial processes, including fission/fusion dynamics, oxidative phosphorylation, mitophagy, and apoptosis. Dysregulation of m6A machinery disrupts mitochondrial homeostasis, exacerbates oxidative stress and neuroinflammation, and promotes neuronal loss. Importantly, pharmacological or genetic modulation of m6A regulators can restore mitochondrial function, inhibit caspase activation, and dampen pro-inflammatory signaling, underscoring their therapeutic potential. This review consolidates current insights into mitochondrial epitranscriptomics, emphasizing how m6A modifications act as central regulators of mitochondrial stress responses and neurodegeneration.

Humans

Arginine methylation-dependent METTL14-SMN interaction regulates RNA m6A homeostasis.

N6-methyladenosine (m6A) homeostasis is essential for development, and its dysregulation is linked to cancers and neurological disorders. However, the mechanisms regulating m6A remain unclear. Here, we identify the survival of motoneuron (SMN) protein as a novel interaction partner of METTL14, a key component of the m6A methyltransferase complex. SMN binds METTL14 via its Tudor domain in an arginine methylation-dependent manner. Mutations in the SMN Tudor domain identified in spinal muscular atrophy (SMA) disrupt its interaction with METTL14 and reduce m6A levels in patient-derived fibroblasts, linking m6A dysregulation to SMA pathology. Both SMN knockdown and SMA mutations impair m6A deposition on the mRNAs of DNA repair genes, mirroring the effects of METTL14 hypomethylation. Consequently, SMA patient fibroblasts are hypersensitive to DNA-damaging agents due to reduced levels of DNA repair gene expression. To explore the function of METTL14 arginine methylation in vivo, we generated a Mettl14 methylation-deficient mouse model (Mettl14RK). Although this model does not show SMA-like phenotypes, the mutants are partially embryonic lethal and show abnormal hematopoiesis, underscoring a role for methylated METTL14 in early development.

Methyltransferases

Epitranscriptomic Regulation of ALDOA by SHMT2-Mediated m6A Modification Drives Gastric Cancer Malignancy.

Gastric cancer (GC) remains a leading cause of cancer-related mortality worldwide, with limited therapeutic advancements despite progress in early detection. Serine hydroxymethyltransferase 2 (SHMT2), a key metabolic enzyme, and fructose-1,6-bisphosphate aldolase A (ALDOA), a glycolytic enzyme, are implicated in tumor progression. However, the molecular mechanisms linking SHMT2 and ALDOA in GC remain unclear. This study investigates how SHMT2 regulates ALDOA expression via m6A RNA modification to drive GC malignancy. Bioinformatic analyses (TCGA, LinkedOmics, and SRAMP) were used to assess SHMT2 expression in GC patients and identify its correlated genes. In vitro experiments (CCK-8, EdU, Transwell, and wound healing) evaluated the effects of SHMT2 overexpression or knockdown on GC cell proliferation, migration, invasion, and glycolysis. m6A modification of ALDOA was analyzed via MeRIP-PCR and dual-luciferase assays, while RNA stability was assessed using actinomycin D treatment. Xenograft models validated SHMT2's role in vivo. SHMT2 was upregulated in GC tissues and cell lines, correlating with advanced tumor stages and poor prognosis. SHMT2 knockdown suppressed GC cell viability, migration, invasion, and glycolysis, while overexpression enhanced these traits. Mechanistically, SHMT2 increased S-adenosylmethionine levels, promoting ALDOA m6A modification, likely mediated through the predicted site 1 (position 291). This modification stabilized ALDOA mRNA via IGF2BP1 recognition, an m6A reader. ALDOA overexpression reversed the tumor-suppressive effects of SHMT2 knockdown. In vivo, SHMT2 depletion reduced tumor growth and Ki67 expression in xenograft models. In conclusion, SHMT2 drives GC progression by enhancing ALDOA expression through m6A modification and IGF2BP1-mediated stabilization. Targeting the SHMT2-ALDOA axis represents a promising therapeutic strategy for gastric cancer.

Humans