Alterations of m6A RNA methylation regulators contribute to autophagy and immune infiltration in primary Sjögren's syndrome

RNA modifications in cancer

RNA modifications are emerging as critical cancer regulators that influence tumorigenesis and progression. Key modifications, such as N6-methyladenosine (m6A) and 5-methylcytosine (m5C), are implicated in various cellular processes. These modifications are regulated by proteins that write, erase, and read RNA and modulate RNA stability, splicing, translation, and degradation. Recent studies have highlighted their roles in metabolic reprogramming, signaling pathways, and cell cycle control, which are essential for tumor proliferation and survival. Despite these scientific advances, the precise mechanisms by which RNA modifications affect cancer remain inadequately understood. This review comprehensively examines the role RNA modifications play in cancer proliferation, metastasis, and programmed cell death, including apoptosis, autophagy, and ferroptosis. It explores their effects on epithelial-mesenchymal transition (EMT) and the immune microenvironment, particularly in cancer metastasis. Furthermore, RNA modifications' potential in cancer therapies, including conventional treatments, immunotherapy, and targeted therapies, is discussed. By addressing these aspects, this review aims to bridge current research gaps and underscore the therapeutic potential of targeting RNA modifications to improve cancer treatment strategies and patient outcomes.

Molecular mechanism of Wilms tumour 1-associated protein in diabetes-related dry eye disease by mediating m6A methylation modification of lncRNA NEAT1

Background: Dry eye disease (DED) is often secondary to diabetes mellitus (DM).Purpose: This study is to explore the action of Wilms tumor 1-associated protein (WTAP) in DM-DED via lncRNA NEAT1 m6A methylation.Methods: DM-DED mouse models were treated with sh-WTAP/sh-NEAT1, followed by assessment of corneal epithelial damage/histopathological changes. HCE-2 cells were exposed to hyperosmotic conditions to establish in vitro DED models and treated with oe-NEAT1/sh-NEAT1/sh-WTAP/nigericin (an NLRP3 inflammasome inducer). Cell viability/apoptosis were evaluated by CCK-8/TUNEL. Levels of WTAP/NEAT1/inflammatory factors/NLRP3 inflammasome- and apoptosis-related markers were determined. m6A modification was examined by MeRIP-qPCR and NEAT1 stability was also detected.Results: DM-DED mice exhibited up-regulated WTAP/NEAT1 expression and severe corneal damage, whereas WTAP/NEAT1 knockdown alleviated inflammation/corneal damage. In hyperosmolarity-induced HCE-2 cells, NEAT1 aggravated inflammation and apoptosis, while NEAT1 knockdown suppressed NLRP3 inflammasome activation and ameliorated cell injury. Hyperosmolarity-induced WTAP expression increased m6A modification and NEAT1 mRNA stability. WTAP mediated m6A methylation of NEAT1 and NLRP3 inflammasome activation in DM-DED mice.

EZH2 promotes B-cell autoimmunity in primary Sjogren's syndrome via METTL3-mediated m6A modification

OBJECTIVE

Enhancer of zeste homologue 2 (EZH2) plays an important role in promoting B-cell activation and differentiation. This study aimed to elucidate the role of EZH2 in the B-cell autoimmune response in primary Sjögren's syndrome (pSS) and to explore the therapeutic potential of inhibiting EZH2 in pSS.

METHODS

Single-cell RNA sequencing analysis of B cells in peripheral blood from pSS patients was conducted to identify abnormal expression of EZH2 and METTL3 in B-cell subsets. The levels of EZH2 were further validated across multiple B-cell subsets and the salivary glands (SGs) of pSS patients, as well as three different mouse models of Sjögren's syndrome (SS). Correlation analyses were performed to explore the relationship between the expression of EZH2 and clinical features of pSS patients. Following EZH2 inhibition, SS-like signs and antibody production were assessed in an experimental Sjögren syndrome (ESS) mouse model. RNA sequencing (RNA-seq) and chromatin immunoprecipitation sequencing (ChIP-seq) data post-EZH2 inhibition were bioinformatically analyzed to identify the EZH2 targets in pSS. ChIP-qPCR was performed to validate the binding of H3K27me3 to the CDKN1A promoter. Flow cytometric apoptosis analysis and Carboxy Fluorescein Succinimidyl Ester (CFSE) assay were used to assess the impact of an EZH2 inhibitor on B-cell apoptosis and proliferation. Additionally, METTL3 expression and its correlation with disease activity were analyzed in pSS patients. EZH2 expression was examined after METTL3 knockdown. METTL3-RNA immunoprecipitation (RIP) and actinomycin D assays were conducted to confirm the direct binding of METTL3 to EZH2 mRNA and its impact on mRNA stability. M6A-RIP-qPCR was performed to validate the presence of m6A modifications on EZH2 mRNA.

RESULTS

EZH2 was found upregulated in multiple B-cell subsets from the peripheral blood and SGs of pSS patients, as well as in three different animal models of SS. The expression of EZH2 in B cells was positively correlated with the ESSDAI score, which is a measure of disease activity. With treatment of EZH2 inhibitor, SS-like signs alleviated and autoantibody production reduced in ESS mice. Similarly, in pSS patients, METTL3 expression was increased in the SGs and peripheral blood CD19+ B cells, also showing a positively correlated with the ESSDAI score. With knockdown of METTL3, the expression of EZH2 reduced. Mechanistically, EZH2 inhibited B-cell apoptosis and promoted B-cell proliferation by catalyzing H3K27me3 modification at the CDKN1A locus. Furthermore, METTL3 bound to EZH2 mRNA and increased m6A modification on EZH2 mRNA, enhancing its stability and promoting EZH2 expression.

CONCLUSIONS

The upregulation of EZH2 mediated by METTL3 is implicated in the B-cell autoimmune response in pSS. Inhibition of EZH2 presents a promising therapeutic strategy for pSS treatment.

Genome-wide identification of cell type-specific susceptibility genes for Juvenile dermatomyositis through the analysis of N6-methyladenosine-associated SNPs

Genome-wide association studies (GWASs) have pinpointed genetic loci associated with juvenile dermatomyositis (JDM). Functional genes within the GWAS loci may be cell type-specific, but their identity remains largely unknown. N6-methyladenosine (m6A) plays a pivotal role in regulating various cellular processes and is linked to autoimmune diseases. This study aimed to underscore the potential functional genes within the GWAS loci through the analysis of m6A-associated SNPs (m6A-SNPs), specifically within relevant cell types. JDM-associated m6A-SNPs were identified from the GWAS summary dataset. The correlation between m6A-SNPs and gene expression was assessed through bulk tissue and single-cell eQTL analyses. To further investigate the relationship between gene expression and JDM, Mendelian randomization analysis was employed. Additionally, differential expression analyses were conducted on bulk tissues, as well as single-cell transcriptomic data comprising 6 JDM patients and 11 juvenile controls (99,396 cells). Seven m6A-SNPs associated with JDM were identified. Bulk tissue analysis revealed differential expression of HLA-DPA1, HLA-DPB1, MICB, HLA-A, HLA-F, HLA-DQB2, HLA-DRB5, TAP2, PSMB9, MICA, AIF1, and DDX39B influenced by m6A-SNPs, all showing associations with JDM in both differential expression and Mendelian randomization analyses. In single-cell analysis, the six m6A-SNPs within the HLA locus acted as cell-type-specific eQTLs, correlating with the expression of HLA-A, HLA-B, HLA-C, HLA-DPB1, HLA-DQA1, HLA-DQB1 and HLA-DRB1 in myeloid, T or B cells. Notably, these genes displayed abnormal expression in T, B, and myeloid cells of JDM patients. The present study identified m6A-SNPs within JDM susceptibility genes, shedding light on the intricate interplay between m6A-SNPs, gene expression, and JDM.

The Role of m6A Methylation in Tumor Immunity and Immune-Associated Disorder

N6-methyladenosine (m6A) represents the most prevalent and significant internal modification in mRNA, with its critical role in gene expression regulation and cell fate determination increasingly recognized in recent research. The immune system, essential for defense against infections and maintaining internal stability through interactions with other bodily systems, is significantly influenced by m6A modification. This modification acts as a key post-transcriptional regulator of immune responses, though its effects on different immune cells vary across diseases. This review delineates the impact of m6A modification across major system-related cancers-including those of the respiratory, digestive, endocrine, nervous, urinary reproductive, musculoskeletal system malignancies, as well as acute myeloid leukemia and autoimmune diseases. We explore the pathogenic roles of m6A RNA modifications within the tumor immune microenvironment and the broader immune system, highlighting how RNA modification regulators interact with immune pathways during disease progression. Furthermore, we discuss how the expression patterns of these regulators can influence disease susceptibility to immunotherapy, facilitating the development of diagnostic and prognostic models and pioneering new therapeutic approaches. Overall, this review emphasizes the challenges and prospective directions of m6A-related immune regulation in various systemic diseases throughout the body.

The role of RNA methylation in tumor immunity and its potential in immunotherapy

RNA methylation, a prevalent post-transcriptional modification, has garnered considerable attention in research circles. It exerts regulatory control over diverse biological functions by modulating RNA splicing, translation, transport, and stability. Notably, studies have illuminated the substantial impact of RNA methylation on tumor immunity. The primary types of RNA methylation encompass N6-methyladenosine (m6A), 5-methylcytosine (m5C), N1-methyladenosine (m1A), and N7-methylguanosine (m7G), and 3-methylcytidine (m3C). Compelling evidence underscores the involvement of RNA methylation in regulating the tumor microenvironment (TME). By affecting RNA translation and stability through the "writers", "erasers" and "readers", RNA methylation exerts influence over the dysregulation of immune cells and immune factors. Consequently, RNA methylation plays a pivotal role in modulating tumor immunity and mediating various biological behaviors, encompassing proliferation, invasion, metastasis, etc. In this review, we discussed the mechanisms and functions of several RNA methylations, providing a comprehensive overview of their biological roles and underlying mechanisms within the tumor microenvironment and among immunocytes. By exploring how these RNA modifications mediate tumor immune evasion, we also examine their potential applications in immunotherapy. This review aims to provide novel insights and strategies for identifying novel targets in RNA methylation and advancing cancer immunotherapy efficacy.

Identification of ferroptosis-related diagnostic markers in primary Sjögren's syndrome based on machine learning

BACKGROUND

Primary Sjogren's syndrome (pSS) is a common autoimmune disorder that affects up to 0.3-3% of the global population. Ferroptosis has recently been identified to play a significant role in autoimmune diseases. However, the molecular mechanisms of ferroptosis in the initiation and progression of pSS remains unclear.

MATERIAL AND METHODS

To investigate the molecular mechanisms underlying the occurrence and progression of pSS, we utilized a comprehensive approach by integrating data obtained from the Gene Expression Omnibus (GEO) database with data from the FerrDb database to identify the ferroptosis-related differentially expressed genes (DEGs). Furthermore, we implemented an innovative transcriptomic analysis method utilizing a computer-aided algorithm to establish a network between hub genes associated with ferroptosis and the immune microenvironment in pSS patients.

RESULTS

Our results revealed significant differences in the gene expression profiles of pSS samples compared to normal tissues, with 1,830 significantly up-regulated genes and 1,310 significantly down-regulated genes. In addition, our results showed a significant increase in the proportions of B cells and CD4+ T cells in pSS samples compared to normal tissues. AND then, our analysis revealed that a combination of six ferroptosis-related genes, including TBK1, SLC1A4, PIK3CA, ENO3, EGR1, and ATG5, could serve as optimal markers for the diagnosis of pSS. The combined analysis of these six genes accurately diagnosed the occurrence of pSS.

CONCLUSIONS

This study offers valuable insights into the pathogenesis of pSS and highlights the importance of targeting ferroptosis-related DEGs, which suggests a novel treatment strategy for pSS.

Insights into the Roles of Epigenetic Modifications in Ferroptosis

Ferroptosis is a non-apoptotic mode of cell death driven by membrane lipid peroxidation and is characterized by elevated intracellular levels of Fe2+, ROS, and lipid peroxidation. Studies have shown that ferroptosis is related to the development of multiple diseases, such as cancer, neurodegenerative diseases, and acute myeloid leukemia. Ferroptosis plays a dual role in the occurrence and development of these diseases. Ferroptosis mainly involves iron metabolism, ROS, and lipid metabolism. Various mechanisms, including epigenetic regulation, have been reported to be deeply involved in ferroptosis. Abnormal epigenetic modifications have been reported to promote tumor onset or other diseases and resistance to chemotherapy drugs. In recent years, diversified studies have shown that epigenetic modification is involved in ferroptosis. In this review, we reviewed the current resistance system of ferroptosis and the research progress of epigenetic modification, such as DNA methylation, RNA methylation, non-coding RNAs, and histone modification in cancer and other diseases by regulating ferroptosis.

N6-methyladenosine methylation in ophthalmic diseases: From mechanisms to potential applications

N6-methyladenosine (m6A) modification, as the most common modification method in eukaryotes, is widely involved in numerous physiological and pathological processes, such as embryonic development, malignancy, immune regulation, and premature aging. Under pathological conditions of ocular diseases, changes in m6A modification and its metabolism can be detected in aqueous and vitreous humor. At the same time, an increasing number of studies showed that m6A modification is involved in the normal development of eye structures and the occurrence and progress of many ophthalmic diseases, especially ocular neovascular diseases, such as diabetic retinopathy, age-related macular degeneration, and melanoma. In this review, we summarized the latest progress regarding m6A modification in ophthalmic diseases, changes in m6A modification-related enzymes in various pathological states and their upstream and downstream regulatory networks, provided new prospects for m6A modification in ophthalmic diseases and new ideas for clinical diagnosis and treatment.

Identification of mitophagy-related biomarkers in human osteoporosis based on a machine learning model

Background: Osteoporosis (OP) is a chronic bone metabolic disease and a serious global public health problem. Several studies have shown that mitophagy plays an important role in bone metabolism disorders; however, its role in osteoporosis remains unclear. Methods: The Gene Expression Omnibus (GEO) database was used to download GSE56815, a dataset containing low and high BMD, and differentially expressed genes (DEGs) were analyzed. Mitochondrial autophagy-related genes (MRG) were downloaded from the existing literature, and highly correlated MRG were screened by bioinformatics methods. The results from both were taken as differentially expressed (DE)-MRG, and Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed. Protein-protein interaction network (PPI) analysis, support vector machine recursive feature elimination (SVM-RFE), and Boruta method were used to identify DE-MRG. A receiver operating characteristic curve (ROC) was drawn, a nomogram model was constructed to determine its diagnostic value, and a variety of bioinformatics methods were used to verify the relationship between these related genes and OP, including GO and KEGG analysis, IP pathway analysis, and single-sample Gene Set Enrichment Analysis (ssGSEA). In addition, a hub gene-related network was constructed and potential drugs for the treatment of OP were predicted. Finally, the specific genes were verified by real-time quantitative polymerase chain reaction (RT-qPCR). Results: In total, 548 DEGs were identified in the GSE56815 dataset. The weighted gene co-expression network analysis(WGCNA) identified 2291 key module genes, and 91 DE-MRG were obtained by combining the two. The PPI network revealed that the target gene for AKT1 interacted with most proteins. Three MRG (NELFB, SFSWAP, and MAP3K3) were identified as hub genes, with areas under the curve (AUC) 0.75, 0.71, and 0.70, respectively. The nomogram model has high diagnostic value. GO and KEGG analysis showed that ribosome pathway and cellular ribosome pathway may be the pathways regulating the progression of OP. IPA showed that MAP3K3 was associated with six pathways, including GNRH Signaling. The ssGSEA indicated that NELFB was highly correlated with iDCs (cor = -0.390, p < 0.001). The regulatory network showed a complex relationship between miRNA, transcription factor(TF) and hub genes. In addition, 4 drugs such as vinclozolin were predicted to be potential therapeutic drugs for OP. In RT-qPCR verification, the hub gene NELFB was consistent with the results of bioinformatics analysis. Conclusion: Mitophagy plays an important role in the development of osteoporosis. The identification of three mitophagy-related genes may contribute to the early diagnosis, mechanism research and treatment of OP.

Significance of m6A in subtype identification, immunological evolution, and therapeutic sensitivity of RA

N6-methyladenosine (m6A) is one kind of important epigenetic modification pattern which is extensively involved in immune regulation. The development and progression of autoimmune diseases are closely related to immune dysregulation. Considering that rheumatoid arthritis (RA) is a typical autoimmune disease, the m6A process might be one of the important regulatory mechanisms in the pathogenesis of RA. In this study, we identified five differentially expressed m6A regulators in normal and RA samples from the GEO database. With these five regulators, we constructed the nomogram, and it could accurately identify the risk of RA morbidity. Next, we identified 121 differentially expressed genes (DEGs) between normal and RA samples, of which 36 DEGs were co-expressed with these five m6A regulators. We noted that these DEGs were highly enriched in multiple immunoregulatory signaling pathways, such as cytokine-mediated immune cell chemotaxis, adhesion, and activation. To further characterize the heterogeneity of immunological features, we clustered the RA samples into two subtypes. The C2 subtype has higher infiltration levels of pro-inflammatory cells and activity of pro-inflammatory signaling pathways. Thus, the inflammatory response might be more vigorous in the C2 subtype. Next, we constructed the m6Asig system with the SVM machine learning algorithms and least absolute shrinkage and selection operator (LASSO) regression. The m6Asig could accurately distinguish the C1 and C2 subtypes, which indicated that the m6Asig could be a potential biomarker for the inflammatory activity of RA. Finally, by comparing the information from the CellMiner, TTD, and DrugBank databases, we determined 25 drugs. The targets of these drugs were positively correlated with m6Asig. To be clarified, the above findings were derived from bioinformatics and statistical analyses, and further experimental validation still requires. In summary, this study further revealed the m6A and immunoregulation mechanisms in RA pathogenesis. Also, the m6Asig could be a novel biomarker with potential applicability in the clinical management of RA.

Novel insights into the regulatory role of N6-methyladenosine methylation modified autophagy in sepsis

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. It is characterized by high morbidity and mortality and one of the major diseases that seriously hang over global human health. Autophagy is a crucial regulator in the complicated pathophysiological processes of sepsis. The activation of autophagy is known to be of great significance for protecting sepsis induced organ dysfunction. Recent research has demonstrated that N6-methyladenosine (m6A) methylation is a well-known post-transcriptional RNA modification that controls epigenetic and gene expression as well as a number of biological processes in sepsis. In addition, m6A affects the stability, export, splicing and translation of transcripts involved in the autophagic process. Although it has been suggested that m6A methylation regulates the biological metabolic processes of autophagy and is more frequently seen in the progression of sepsis pathogenesis, the underlying molecular mechanisms of m6A-modified autophagy in sepsis have not been thoroughly elucidated. The present article fills this gap by providing an epigenetic review of the processes of m6A-modified autophagy in sepsis and its potential role in the development of novel therapeutics.

Modes and Mechanisms of Salivary Gland Epithelial Cell Death in Sjogren's Syndrome

Sjogren's syndrome is an autoimmune disease in middle and old-aged women with a dry mucosal surface, which is caused by the dysfunction of secretory glands, such as the oral cavity, eyeballs, and pharynx. Pathologically, Sjogren's syndrome are characterized by lymphocyte infiltration into the exocrine glands and epithelial cell destruction caused by autoantibodies Ro/SSA and La/SSB. At present, the exact pathogenesis of Sjogren's syndrome is unclear. Evidence suggests epithelial cell death and the subsequent dysfunction of salivary glands as the main causes of xerostomia. This review summarizes the modes of salivary gland epithelial cell death and their role in Sjogren's syndrome progression. The molecular mechanisms involved in salivary gland epithelial cell death during Sjogren's syndrome as potential leads to treating the disease are also discussed.

Integrated DNA Methylation and Transcriptomics Analyses of Lacrimal Glands Identify the Potential Genes Implicated in the Development of Sjögren's Syndrome-Related Dry Eye

Purpose

Sjögren's syndrome-related dry eye (SS-related dry eye) is an intractable autoimmune disease characterized by chronic inflammation of lacrimal glands (LGs), where epigenetic factors are proven to play a crucial role in the pathogenesis of this disease. However, the alteration of DNA methylation in LGs and its role in the pathogenesis of SS-related dry eye is still unknown. Here, we performed an integrated analysis of DNA methylation and RNA-Seq data in LGs to identify novel DNA methylation-regulated differentially expressed genes (MeDEGs) in the pathogenesis of SS-related dry eye.

Methods

The DNA methylation and transcription profiles of LGs in NOD mice at different stages of SS-related dry eye (4-, 8-, 12- and 16 weeks old) were generated by reduced representation bisulfite sequencing (RRBS) and RNA-Seq. The differentially methylated genes (DMGs) and differentially expressed genes (DEGs) were analyzed by MethylKit R package and edgeR. Correlation analysis between methylation level and mRNA expression was conducted with R software. The functional correlation of DMGs and DEGs was analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Finally, LG tissues from another litter of NOD mice were collected for methylation-specific polymerase chain reaction (MSP) and quantitative real-time PCR (qRT-PCR) to validate the methylation and expression levels of key genes. CD4+ cell infiltration of LGs was detected by immunofluorescence staining.

Results

Hypermethylation of LGs was identified in NOD mice with the progression of SS-related dry eye and the DMGs were mainly enriched in the GTPases activation and Ras signaling pathway. RNA-seq analysis revealed 1321, 2549, and 3712 DEGs in the 8-, 12- and 16-week-old NOD mice compared with 4-week-old normal control mice. For GO analysis, the DEGs were mainly enriched in T cell immune responses. Further, a total of 140 MeDEGs were obtained by integrated analysis of methylome and transcriptome, which were primarily enriched in T cell activation, proliferation and differentiation. Based on the main GO terms and KEGG pathways of MeDEGs, 8 genes were screened out. The expression levels of these key genes, especially Itgal, Vav1, Irf4 and Icosl, were verified to elevate after the onset of SS-related dry eye in NOD mice and positively correlated with the extent of inflammatory cell infiltration in LGs. Immunofluorescence assay revealed that CD4+ cell infiltration dramatically increased in LGs of SS-related dry eye mice compared with the control mice. And the expression levels of four genes showed significantly positive correlation with the extent of CD4+ cell infiltration in LGs. MSP showed the hypomethylation of the Irf4 and Itgal promoters in NOD mice with SS-related dry eye compared to control group.

Conclusion

Our study revealed the critical role of epigenetic regulation of T cell immunity-related genes in the progression of SS-related dry eye and reminded us that DNA methylation-regulated genes such as Itgal, Vav1, Irf4 and Icosl may be used as new targets for SS-related dry eye therapy.

N6-Methyladenosine (m6A) Modification in Natural Immune Cell-Mediated Inflammatory Diseases

The post-transcriptional N6-methyladenosine (m6A) modification of RNA influences stability, transport, and translation with implications for various physiological and pathological processes. Immune cell development, differentiation, and activation are also thought to be regulated by m6A and affect host defense against pathogens and inflammatory response with impacts on infectious, neoplastic, autoimmune, cardiovascular, hepatic, and osteal diseases. The current review summarizes recent research on m6A in monocyte/macrophages, neutrophils, dendritic cells, natural killer cells, and microglia and gives insights into epigenetic modifications of the immune system and novel therapeutic strategies for immune-related diseases.

M6A methylation modification in autoimmune diseases, a promising treatment strategy based on epigenetics

BACKGROUND

N6-methyladenosine (m6A) methylation modification is involved in the regulation of various biological processes, including inflammation, antitumor, and antiviral immunity. However, the role of m6A modification in the pathogenesis of autoimmune diseases has been rarely reported.

METHODS

Based on a description of m6A modification and the corresponding research methods, this review systematically summarizes current insights into the mechanism of m6A methylation modification in autoimmune diseases, especially its contribution to rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE).

RESULTS

By regulating different biological processes, m6A methylation is involved in the pathogenesis of autoimmune diseases and provides a promising biomarker for the diagnosis and treatment of such diseases. Notably, m6A methylation modification is involved in regulating a variety of immune cells and mitochondrial energy metabolism. In addition, m6A methylation modification plays a role in the pathological processes of RA, and m6A methylation-related genes can be used as potential targets in RA therapy.

CONCLUSIONS

M6A methylation modification plays an important role in autoimmune pathological processes such as RA and SLE and represents a promising new target for clinical diagnosis and treatment, providing new ideas for the treatment of autoimmune diseases by targeting m6A modification-related pathways.

m6A methylation: a potential key player in understanding and treating COVID-2019 infection

Since its discovery in 2019, coronavirus disease 2019 (COVID-2019) spans a wide clinical spectrum from the asymptomatic stage, mild infection, to severe pneumonia. In patients with COVID-2019, factors such as advanced age, diabetes, or hypertension are associated with a significantly increased risk of severe diseases and death. Of note, the mechanisms underlying differences in the risk and symptoms of COVID-2019 among different populations are still poorly characterized. Accordingly, it is imperative to elucidate potential pathophysiological mechanisms and develop targeted therapeutic approaches for COVID-2019 infection. N6-methyladenosine (m6A) is one of the most common modifications in mammalian RNA transcripts and is widely found in messenger RNAs and some non-coding RNAs. It has been reported that m6A methylation modifications are present in viral RNA transcripts, which are of great significance for the regulation of the viral life cycle. Furthermore, m6A methylation has recently been found to be strongly associated with COVID-2019 infection. Therefore, this article reviews recent advances in studies related to the role of m6A methylation in COVID-2019 infection.

Increased METTL3 expression and m6A RNA methylation may contribute to the development of dry eye in primary Sjögren's syndrome

BACKGROUND

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disorder defined by xerostomia and keratoconjunctivitis sicca, and its etiology remains unknown. N6-methyladenosine (m⁶A) is the predominant posttranscriptional modification in eukaryotic mRNAs and is dynamically regulated by m⁶A regulators. Dysregulation of m⁶A modification is closely associated with several autoimmune disorders, but the role of m⁶A modification in pSS remains unknown. This study investigated the potential role of m⁶A and m⁶A-related regulators in pSS patients with dry eye.

METHODS

This cross-sectional study included forty-eight pSS patients with dry eye and forty healthy controls (HCs). Peripheral blood mononuclear cells (PBMCs) were isolated, and the level of m⁶A in total RNA was measured. The expression of m⁶A regulators was determined utilizing real-time PCR and western blotting. The serological indicators detected included autoantibodies, immunoglobulins (Igs), complement factors (Cs), and inflammatory indicators. Dry eye symptoms and signs were measured, including the ocular surface disease index, Schirmer's test (ST), corneal fluorescein staining score (CFS), and tear break-up time. Spearman's correlation coefficient was employed to assess the associations of m⁶A and m⁶A-related regulator expression with clinical characteristics.

RESULTS

The expression level of m⁶A was markedly increased in the PBMCs of pSS patients with dry eye compared to HCs (P _value<0.001). The relative mRNA and protein expression levels of the m⁶A regulators methyltransferase-like 3 (METTL3) and YT521-B homology domains 1 were markedly elevated in pSS patients with dry eye (both P _value<0.01). The m⁶A RNA level was found to be positively related to METTL3 expression in pSS patients (r = 0.793, P _value<0.001). Both the m⁶A RNA level and METTL3 mRNA expression correlated with the anti-SSB antibody, IgG, ST, and CFS (all P _values < 0.05). The m⁶A RNA level was associated with C4 (r = -0.432, P _value = 0.002), while METTL3 mRNA expression was associated with C3 (r = -0.313, P _value = 0.030).

CONCLUSIONS

Our work revealed that the upregulation of m⁶A and METTL3 was associated with the performance of serological indicators and dry eye signs in pSS patients with dry eye. METTL3 may contribute to the pathogenesis of dry eye related to pSS.

Novel insights into the interplay between m6A modification and programmed cell death in cancer

N6-methyladenosine (m6A) methylation, the most prevalent and abundant RNA modification in eukaryotes, has recently become a hot research topic. Several studies have indicated that m6A modification is dysregulated during the progression of multiple diseases, especially in cancer development. Programmed cell death (PCD) is an active and orderly method of cell death in the development of organisms, including apoptosis, autophagy, pyroptosis, ferroptosis, and necroptosis. As the study of PCD has become increasingly profound, accumulating evidence has revealed the mutual regulation of m6A modification and PCD, and their interaction can further influence the sensitivity of cancer treatment. In this review, we summarize the recent advances in m6A modification and PCD in terms of their interplay and potential mechanisms, as well as cancer therapeutic resistance. Our study provides promising insights and future directions for the examination and treatment of cancers.

The risk of COVID-19 can be predicted by a nomogram based on m6A-related genes

BACKGROUND

The expression of m6A-related genes and their significance in COVID-19 patients are still unknown.

METHODS

The GSE177477 and GSE157103 datasets of the Gene Expression Omnibus were used to extract RNA-seq data. The expression of 26 m6A-related genes and immune cell infiltration in COVID-19 patients were analyzed. Finally, we built and validated a nomogram model to predict the risk of COVID-19 infection.

RESULTS

There were significant differences in 11 m6A regulatory factors between patients with COVID-19 and healthy individuals. The classification of disease subtypes based on m6A-related gene levels can be distinguished. COVID-19 patients in GSE177477 were classified into two categories based on m6A-related genes. The patients in cluster A were all symptomatic, while those in cluster B were asymptomatic. A significant correlation was also found between immune cells and m6A-related genes. Finally, seven m6A-related disease-characteristic genes, HNRNPA2B1, ELAVL1, RBM15, RBM15B, YTHDC1, HNRNPC, and WTAP, were screened to construct a nomogram model for predicting risk. The calibration curve, decision curve analysis, and clinical impact curve analysis were used to show that the nomogram model was effective and had a high net efficacy for risk prediction.

CONCLUSIONS

m6A-related genes were correlated with immune cells. The nomogram model effectively predicted COVID-19 risk. Moreover, m6A-related genes may be associated with the presence or absence of symptoms in COVID-19 patients.