BACKGROUND: Within the tumor microenvironment, survival pressures are prevalent with potent drivers of tumor progression, angiogenesis, and therapeutic resistance. N6-methyladenosine (m6A) methylation has been recognized as a critical post-transcriptional mechanism regulating various aspects of mRNA metabolism. Understanding the intricate interplay between survival pressures and m6A modification provides new insights into the molecular mechanisms underlying hepatocellular carcinoma (HCC) progression and highlights the potential for targeting the survival pressures-m6A axis in HCC diagnosis and treatment.
METHODS: A literature search was conducted in PubMed, MEDLINE, and Web of Science for relevant articles published up to April 2024. The keywords used for the search included hepatocellular carcinoma, cellular survival, survival pressure, N6-methyladenosine, tumor microenvironment, stress response, and hypoxia.
RESULTS: This review delves into the multifaceted roles of survival pressures and m6A RNA methylation in HCC, highlighting how survival pressures modulate the m6A landscape, the impact of m6A modification on survival pressure-responsive gene expression, and the consequent effects on HCC cell survival, proliferation, metastasis, and resistance to treatment. Furthermore, we explored the therapeutic potential of targeting this crosstalk, proposing strategies that leverage the understanding of survival pressures and m6A RNA methylation mechanisms to develop novel, and more effective treatments for HCC.
CONCLUSIONS: The interplay between survival pressures and m6A RNA methylation emerges as a complex regulatory network that influences HCC pathogenesis and progression.

Nonalcoholic fatty liver disease (NAFLD), including its more severe manifestation nonalcoholic steatohepatitis (NASH), is a global public health challenge. Here, we explore the role of deubiquitinating enzyme RPN11 in NAFLD and NASH. Hepatocyte-specific RPN11 knockout mice are protected from diet-induced liver steatosis, insulin resistance, and steatohepatitis. Mechanistically, RPN11 deubiquitinates and stabilizes METTL3 to enhance the m6A modification and expression of acyl-coenzyme A (CoA) synthetase short-chain family member 3 (ACSS3), which generates propionyl-CoA to upregulate lipid metabolism genes via histone propionylation. The RPN11-METTL3-ACSS3-histone propionylation pathway is activated in the livers of patients with NAFLD. Pharmacological inhibition of RPN11 by Capzimin ameliorated NAFLD, NASH, and related metabolic disorders in mice and reduced lipid contents in human hepatocytes cultured in 2D and 3D. These results demonstrate that RPN11 is a novel regulator of NAFLD/NASH and that suppressing RPN11 has therapeutic potential for the treatment.

Of all the chemical modifications of RNAs, the N6-methyladenosine (m6A) modification is the most prevalent and well-characterized RNA modification that is functionally implicated in a wide range of biological processes. The m6A modification occurs in hepatitis B virus (HBV) RNAs and this modification regulates the HBV life cycle in several ways. Thus, understanding the mechanisms underlying m6A modification of HBV RNAs is crucial in understanding HBV infectious process and associated pathogenesis. Here, we describe the currently utilized method in the detection and characterization of m6A-methylated RNAs during viral infection.

BACKGROUND: N6-methyladenosine (m6A) methylation modification exists in Epstein-Barr virus (EBV) primary infection, latency, and lytic reactivation. It also modifies EBV latent genes and lytic genes. EBV-associated gastric cancer (EBVaGC) is a distinctive molecular subtype of GC. We hypothesized EBV and m6A methylation regulators interact with each other in EBVaGC to differentiate it from other types of GC.
OBJECTIVE: To investigate the mechanisms of m6A methylation regulators in EBVaGC to determine the differentiating factors from other types of GC.
METHODS: First, The Cancer Gene Atlas and Gene Expression Omnibus databases were used to analyze the expression pattern of m6A methylation regulators between EBVaGC and EBV-negative GC (EBVnGC). Second, we identified Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment of m6A-related differentially expressed genes. We quantified the relative abundance of immune cells and inflammatory factors in the tumor microenvironment (TME). Finally, cell counting kit-8 cell proliferation test, transwell test, and flow cytometry were used to verify the effect of insulin-like growth factor binding protein 1 (IGFBP1) in EBVaGC cell lines.
RESULTS: m6A methylation regulators were involved in the occurrence and development of EBVaGC. Compared with EBVnGC, the expression levels of m6A methylation regulators Wilms tumor 1-associated protein, RNA binding motif protein 15B, CBL proto-oncogene like 1, leucine rich pentatricopeptide repeat containing, heterogeneous nuclear ribonucleoprotein A2B1, IGFBP1, and insulin-like growth factor 2 binding protein 1 were significantly downregulated in EBVaGC (P < 0.05). The overall survival rate of EBVaGC patients with a lower expression level of IGFBP1 was significantly higher (P = 0.046). GO and KEGG functional enrichment analyses showed that the immunity pathways were significantly activated and rich in immune cell infiltration in EBVaGC. Compared with EBVnGC, the infiltration of activated CD4+ T cells, activated CD8+ T cells, monocytes, activated dendritic cells, and plasmacytoid dendritic cells were significantly upregulated in EBVaGC (P < 0.001). In EBVaGC, the expression level of proinflammatory factors interleukin (IL)-17, IL-21, and interferon-γ and immunosuppressive factor IL-10 were significantly increased (P < 0.05). In vitro experiments demonstrated that the expression level of IGFBP1 was significantly lower in an EBVaGC cell line (SNU719) than in an EBVnGC cell line (AGS) (P < 0.05). IGFBP1 overexpression significantly attenuated proliferation and migration and promoted the apoptosis levels in SNU719. Interfering IGFBP1 significantly promoted proliferation and migration and attenuated the apoptosis levels in AGS.
CONCLUSIONS: m6A regulators could remodel the TME of EBVaGC, which is classified as an immune-inflamed phenotype and referred to as a \"hot\" tumor. Among these regulators, we demonstrated that IGFBP1 affected proliferation, migration, and apoptosis.

Long-time hypoxia induced cardiomyocyte apoptosis is an important mechanism of myocardial ischemia (MI) injury. Interestingly, long noncoding RNA myocardial infarction-associated transcript (LncMIAT) has been involved in the regulation of MI injury; however, the underlying mechanism by which LncMIAT affects the progression of hypoxia-induced cardiomyocyte apoptosis remains unclear. In the present study, hypoxia was found to promote cardiomyocyte apoptosis through an increased expression of LncMIAT in vitro. Biological investigations and dual-luciferase gene reporter assay further revealed that LncMIAT was able to bind with miR-708-5p to upregulate the p53-mediated cell death of the cardiomyocytes. Silencing of LncMIAT or overexpression of miR-708-5p led to a significant reduction in p53-mediated cardiomyocyte apoptosis. The methylated RNA immunoprecipitation (MeRIP)-qPCR results showed that hypoxia exerted its effects on LncMIAT through AKLBH5-N6-methyladenosine (m6A) methylation and therefore hypoxia was shown to trigger HL-1 cardiomyocyte apoptosis via the m6A methylation-mediated LncMIAT/miR-708-5p/p53 axis. Silencing of AKLBH5 significantly alleviated the m6A methylation-mediated LncMIAT upregulation and p53-mediated cardiomyocyte apoptosis, while promoted miR-708-5p expression. Taken together, the present study highlighted that LncMIAT could act as a key biological target during hypoxia-induced cardiomyocyte apoptosis. In addition, it was shown that hypoxia could promote cardiomyocyte apoptosis through regulation of the m6A methylation-mediated LncMIAT/miR-708-5p/p53 signaling axis.

Asthma is a chronic respiratory disease that is characterized by airway inflammation, excessive mucus production, and airway remodeling. Prevention and treatment for asthma is an urgent issue in clinical studies. In recent years, N6-methyladenosine methylation (m6A) has emerged as a promising regulatory approach involved in multiple diseases. ALKBH5 (alkB homolog 5) is a demethylase widely studied in disease pathologies. This work aimed to explore the regulatory mechanisms underlying the ALKBH5-regulated asthma. We established an interleukin-13 (IL-13)-stimulated cell model to mimic the in vitro inflammatory environment of asthma. ALKBH5 knockdown in bronchial epithelial cells was performed using siRNAs, and the knockdown efficacy was analyzed by quantitative PCR (qPCR). Cell viability and proliferation were measured by cell counting kit 8 (CCK-8) and colony formation assay. The ferroptosis was assessed by measuring the total iron, Fe2+, lipid reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD) levels. The enrichment of N6-methyladenosine methylation (m6A) modification was detected by the MeRIP assay. Knockdown of ALKBH5 significantly elevated the survival and colony formation ability of bronchial epithelial cells in the IL-13 induction model. The levels of total iron, Fe2+, lipid ROS, and MDA were remarkedly elevated, and the SOD level was reduced in IL-13-induced bronchial epithelial cells, and depletion of ALKBH5 reversed these effects. Knockdown of ALKBH5 elevated the enrichment of m6A modification and expression of glutathione peroxidase 4 (GPX4). Knockdown of GPX4 abolished the pro-proliferation and anti-ferroptosis effects of siALKBH5. Knockdown of ALKBH5 improved the proliferation of bronchial epithelial cells and alleviated cell ferroptosis.

Background: N6-methyladenosine (m6A) is the most common and abundant mRNA modification, playing an essential role in biological processes and tumor development. However, the role of m6A methylation in skin cutaneous melanoma (SKCM) is not yet clear. This study analyzed the expression of m6A-related functional genes in SKCM and aimed to explore the key demethylase ALKBH5 mediated m6A modification and its potential mechanism in human SKCM. Methods: Based on public databases, the m6A-related gene expression landscape in SKCM was portrayed. MeRIP-Seq and RNA-Seq were used to recognize the downstream target of ALKBH5. In vivo and in vitro functional phenotype and rescue functional experiments were performed to explore the mechanism of the ALKBH5-m6A-ABCA1 axis in SKCM. Results: We found ALKBH5 upregulated in SKCM, associated with poor prognosis. ALKBH5 can promote melanoma cell proliferation, colony formation, migration, and invasion and inhibit autophagy in vitro, facilitating tumor growth and metastasis in vivo. We identified ABCA1, a membrane protein that assists cholesterol efflux, as a downstream target of ALKBH5-mediated m6A demethylation. Finally, our data demonstrated that ALKBH5 promoted SKCM via mediating ABCA1 downregulation by reducing ABCA1 mRNA stability in an m6A-dependent manner. Conclusion: Our findings exhibited the functional value of the key demethylase ALKBH5 mediated m6A modification in the progression of SKCM, suggesting the ALKBH5-m6A-ABCA1 axis as a potential therapeutic target in SKCM.

BACKGROUND: Ischemia-reperfusion injury to the central nervous system often causes severe complications. The activation of endogenous neural stem cells (NSCs) is considered a promising therapeutic strategy for nerve repair. However, the specific biological processes and molecular mechanisms of NSC activation remain unclear, and the role of N6-methyladenosine (m6A) methylation modification in this process has not been explored.
METHODS: NSCs were subjected to hypoxia/reoxygenation (H/R) to simulate ischemia-reperfusion in vivo. m6A RNA methylation quantitative kit was used to measure the total RNA m6A methylation level. Quantitative real-time PCR was used to detect methyltransferase and demethylase mRNA expression levels. Methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) were conducted for NSCs in control and H/R groups, and the sequencing results were analyzed using bioinformatics. Finally, the migration ability of NSCs was identified by wound healing assays, and the proliferative capacity of NSCs was assessed using the cell counting kit-8, EdU assays and cell spheroidization assays.
RESULTS: Overall of m6A modification level and Mettl14 mRNA expression increased in NSCs after H/R treatment. The m6A methylation and expression profiles of mRNAs in NSCs after H/R are described for the first time. Through the joint analysis of MeRIP-seq and RNA-seq results, we verified the proliferation of NSCs after H/R, which was regulated by m6A methylation modification. Seven hub genes were identified to play key roles in the regulatory process. Knockdown of Mettl14 significantly inhibited the proliferation of NSCs. In addition, separate analysis of the MeRIP-seq results suggested that m6A methylation regulates cell migration and differentiation in ways other than affecting mRNA expression. Subsequent experiments confirmed the migration ability of NSCs was suppressed by knockdown of Mettl14.
CONCLUSIONS: The biological behaviors of NSCs after H/R are closely related to m6A methylation of mRNAs, and Mettl14 was confirmed to be involved in cell proliferation and migration.

Diabetic kidney disease (DKD) is a major microvascular complication of diabetes, and hyperglycemic memory associated with diabetes carries the risk of disease occurrence, even after the termination of blood glucose injury. The existence of hyperglycemic memory supports the concept of an epigenetic mechanism involving n6-methyladenosine (m6A) modification. Several studies have shown that m6A plays a key role in the pathogenesis of DKD. This review addresses the role and mechanism of m6A RNA modification in the progression of DKD, including the regulatory role of m6A modification in pathological processes, such as inflammation, oxidative stress, fibrosis, and non-coding (nc) RNA. This reveals the importance of m6A in the occurrence and development of DKD, suggesting that m6A may play a role in hyperglycemic memory phenomenon. This review also discusses how some gray areas, such as m6A modified multiple enzymes, interact to affect the development of DKD and provides countermeasures. In conclusion, this review enhances our understanding of DKD from the perspective of m6A modifications and provides new targets for future therapeutic strategies. In addition, the insights discussed here support the existence of hyperglycemic memory effects in DKD, which may have far-reaching implications for the development of novel treatments. We hypothesize that m6A RNA modification, as a key factor regulating the development of DKD, provides a new perspective for the in-depth exploration of DKD and provides a novel option for the clinical management of patients with DKD.

BACKGROUND: The biological behavior of low-grade glioma (LGG) is significantly affected by N6-methyladenosine (m6A) methylation, an essential epigenetic alteration. Therefore, it is crucial to create a prognostic model for LGG by utilizing genes that regulate m6A methylation.
METHODS: Using TCGA and GTEx databases. We examined m6A modulator levels in LGG and normal tissues, and investigated PD-L1 and PD-1 expression, immune scores, immune cell infiltration, tumor immune microenvironment (TIME) and potential underlying mechanisms in different LGG clusters. We also performed immunohistochemistry and RT-qPCR to identify essential m6A adjustment factor.
RESULTS: The results showed that m6A regulatory element expression was significantly increased in LGG tissues and was significantly associated with TMIE. A substantial increase in PD-L1 and PD-1 levels in LGG tissues and high-risk cohorts was observed. PD-L1 expression was positively correlated with FTO, ZCCHC4, and HNRNPD, whereas PD-1 expression was negatively correlated with FTO, ZC3H7B, and HNRNPD. The prognostic signature created using regulators of m6A RNA methylation was shown to be strongly associated with the overall survival of LGG patients, and FTO and ZCCHC4 were confirmed as independent prognostic markers by clinical samples. Furthermore, the results revealed different TIME characteristics between the two groups of patients, indicating disrupted signaling pathways associated with LGG.
CONCLUSIONS: Our results present that the m6A regulators play vital role in regulating PD-L1/PD-1 expression and the infiltration of immune cells, thereby exerting a sizable impact on the TIME of LGG. Therefore, m6A regulators have precise predictive value in the prognosis of LGG.