The crosstalk between m6A RNA methylation and other epigenetic regulators: a novel perspective in epigenetic remodeling

The DNA N6-adenine methylation target gene GhMAF1 promotes fiber initiation at the base of Gossypium ovules

DNA methylation consists of 5-methylcytosine and N6-methyl deoxyadenosine (6mA) and is crucial in plant development. However, its specific role and potential mechanism to initiate cotton fibers remain unclear. This study employed Oxford Nanopore Technologies (ONT) sequencing to analyze DNA methylation alterations in ZM24 and ZM24 fuzzless-lintless (ZM24fl) during fiber initiation. Our results indicated that DNA 6mA methylation exhibited the most remarkable difference among ovule samples at -2, 0, and 5 d post anthesis of ZM24 and ZM24fl. Subsequently, genes with significant changes in DNA 6mA methylation and transcription during fiber initiation were screened. We found that GhMAF1 displayed significant transcriptional upregulation and 6mA enrichment in its promoter, which could serve as a potential target for DNA 6mA in fiber initiation. Further, we knocked out GhMAF1 using CRISPR-Cas technology and demonstrated that GhMAF1 specifically promotes the initiation of fiber cells at the base of the ovule by mediating the downstream JAZ2/CPC-MML3/MML4 pathway. These findings unveil a novel spatial module of fiber cell initiation on the ovule surface that involves GhMAF1. Ultimately, this work provides significant knowledge for the regulatory network of DNA 6mA modification in fiber initiation to improve fiber yield and quality.

The impact of dysregulation SUMOylation on prostate cancer

Prostate cancer (PCa) remains one of the most common malignancies in men, with its development and progression being governed by complex molecular pathways. SUMOylation, a post-translational modification (PTM) that involves the covalent attachment of small ubiquitin-like modifier (SUMO) proteins to target substrates, has emerged as a critical regulator of various cellular processes such as transcription, DNA repair, cell cycle progression, and apoptosis. Emerging evidence reveals that abnormal SUMOylation may contribute to PCa pathogenesis, and notably, SUMO-associated enzymes are commonly dysregulated in PCa. This review explores the mechanisms by which SUMOylation is implicated in the regulation of key pathways, and summary aberrant expression of SUMO-related enzymes or SUMOylation sites mutations of substrtes in PCa, as well as the therapeutic implications of targeting the SUMO-related enzymes in PCa treatment.

Cis-Regulation of an m6A Eraser by an Insertion Variant Associated with Survival of Patients With Non-Small Cell Lung Carcinoma

N6-methyladenosine (m6A) serves as one of the crucial RNA modifications for genes involved in cancer progression. Here, 7273 expression quantitative trait loci potentially regulating 30 m6A pathway genes are identified from the GTEx database, with 69 single nucleotide polymorphisms significantly associated with survival of non-small cell lung carcinoma (NSCLC) patients (n = 1523) from the ongoing genome-wide association study after false positive probability tests. Notably, the rs151198415 locus, situated in a potential enhancer region, demonstrated a prolonged survival effect with the C>CCACG insertion, which is validated in an independent prospective cohort (n = 237), yielding a pooled hazard ratio of 0.72 (p = 0.007). Mechanistically, the rs151198415 C>CCACG insertion engaged in long-range interaction with the promoter of m6A eraser ALKBH5, promoting ALKBH5 transcription by the creation of an EGR1 binding site. Then, ALKBH5 upregulated FBXL5 expression by m6A demethylation, which is dependent on the ALKBH5 H204 amino acid site and specific m6A sites on FBXL5 mRNA. Finally, the ALKBH5-FBXL5 axis reduces intracellular reactive oxygen species levels, leading to PI3K/AKT and NF-kB pathway inhibition and consequently suppresses NSCLC proliferation and metastasis in vitro and in vivo. Triggered by an insertion variant, this remote cis-regulation of m6A eraser and the downstream molecular events modulate the survival of NSCLC patients.

Super-enhancer-associated circPVT1 promotes malignancy of hepatocellular carcinoma via YBX1-mediated RRM2 activation

Circular RNAs (circRNAs), the essential members of epigenetic reprogramming, are emerging as an appealing layer in hepatocellular carcinoma (HCC). Super-enhancers (SEs) are large clusters of transcriptional enhancers with the tremendous gene activation potential and are extensively investigated in cancer research. The present study explores and uncovers an SE-related circRNA circPVT1, identifying its biological functions and downstream mechanisms in HCC. CircPVT1 is upregulated in HCC, serving as an independent prognostic factor for patients with HCC. Enrichment of H3K27ac and H3K4me1 modifications has been confirmed at the genomic loci of circPVT1's host gene, and the expression of circPVT1 is triggered by SEs. Functionally, circPVT1 enhances cell propagation and mobility capabilities in vitro, and facilitates tumour growth and metastasis in vivo. Mechanistically, circPVT1 recruits YBX1 into the cell nucleus, promoting the transcription of RRM2. Dysregulation of the circPVT1-RRM2 axis advances HCC malignancy, while inhibition of RRM2 or SE alleviates the effects of circPVT1 overexpression. In conclusion, our work demonstrates that circPVT1 is driven by super-enhancers. CircPVT1 promotes HCC progression via YBX1-mediated transcriptional activation of RRM2. These findings provide constructive insights into exploring the pathogenesis of HCC.

The SUMO Family: Mechanisms and Implications in Thyroid Cancer Pathogenesis and Therapy

(1) Background: Small ubiquitin-like modifiers (SUMOs) are pivotal in post-translational modifications, influencing various cellular processes, such as protein localization, stability, and genome integrity. (2) Methods: This review explores the SUMO family, including its isoforms and catalytic cycle, highlighting their significance in regulating key biological functions in thyroid cancer. We discuss the multifaceted roles of SUMOylation in DNA repair mechanisms, protein stability, and the modulation of receptor activities, particularly in the context of thyroid cancer. (3) Results: The aberrant SUMOylation machinery contributes to tumorigenesis through altered gene expression and immune evasion mechanisms. Furthermore, we examine the therapeutic potential of targeting SUMOylation pathways in thyroid cancer treatment, emphasizing the need for further research to develop effective SUMOylation inhibitors. (4) Conclusions: By understanding the intricate roles of SUMOylation in cancer biology, we can pave the way for innovative therapeutic strategies to improve outcomes for patients with advanced tumors.

Crosstalk between RNA m6A modification and epigenetic factors in plant gene regulation

N6-methyladenosine (m6A) is the most abundant modification observed in eukaryotic mRNAs. Advances in transcriptome-wide m6A mapping and sequencing technologies have enabled the identification of several conserved motifs in plants, including the RRACH (R = A/G and H = A/C/U) and UGUAW (W = U or A) motifs. However, the mechanisms underlying deposition of m6A marks at specific positions in the conserved motifs of individual transcripts remain to be clarified. Evidence from plant and animal studies suggests that m6A writer or eraser components are recruited to specific genomic loci through interactions with particular transcription factors, 5-methylcytosine DNA methylation marks, and histone marks. In addition, recent studies in animal cells have shown that microRNAs play a role in depositing m6A marks at specific sites in transcripts through a base-pairing mechanism. m6A also affects the biogenesis and function of chromatin-associated regulatory RNAs and long noncoding RNAs. Although we have less of an understanding of the link between m6A modification and epigenetic factors in plants than in animals, recent progress in identifying the proteins that interact with m6A writer or eraser components has provided insights into the crosstalk between m6A modification and epigenetic factors, which plays a crucial role in transcript-specific methylation and regulation of m6A in plants.

Emerging Orchestrator of Ecological Adaptation: m6A Regulation of Post-Transcriptional Mechanisms

Genetic mechanisms have been at the forefront of our exploration into the substrate of adaptive evolution and phenotypic diversification. However, genetic variation only accounts for a fraction of phenotypic variation. In the last decade, the significance of RNA modification mechanisms has become more apparent in the context of organismal adaptation to rapidly changing environments. RNA m6A methylation, the most abundant form of RNA modification, is emerging as a potentially significant player in various biological processes. Despite its fundamental function to regulate other major post-transcriptional mechanisms such as microRNA and alternative splicing, its role in ecology and evolution has been understudied. This review highlights the potential importance of m6A RNA methylation in ecological adaptation, emphasising the need for further research, especially in natural systems. We focus on how m6A not only affects mRNA fate but also influences miRNA-mediated gene regulation and alternative splicing, potentially contributing to organismal adaptation. The aim of this review is to synthesise key background information to enhance our understanding of m6A mechanisms driving species survival in dynamic environments and motivate future research into the dynamics of adaptive RNA methylation.

m6A epitranscriptomic and epigenetic crosstalk in liver fibrosis: Special emphasis on DNA methylation and non-coding RNAs

Liver fibrosis is a pathological process caused by a variety of chronic liver diseases. Currently, therapeutic options for liver fibrosis are very limited, highlighting the urgent need to explore new treatment approaches. Epigenetic modifications and epitranscriptomic modifications, as reversible regulatory mechanisms, are involved in the development of liver fibrosis. In recent years, researches in epitranscriptomics and epigenetics have opened new perspectives for understanding the pathogenesis of liver fibrosis. Exploring the epigenetic mechanisms of liver fibrosis may provide valuable insights into the development of new therapies for chronic liver diseases. This review primarily focus on the regulatory mechanisms of N6-methyladenosine (m6A) modification, non-coding RNA, and DNA methylation in organ fibrosis. It discusses the interactions between m6A modification and DNA methylation, as well as between m6A modification and non-coding RNA, providing a reference for understanding the interplay between epitranscriptomics and epigenetics.

Regulatory role of N6-Methyladenosine on skeletal muscle development in Hu sheep

N6-Methyladenosine (m6A) RNA modification plays an essential role in many biological processes. To investigate the regulatory role of m6A on the skeletal muscle development in Hu sheep, this study took newborn Hu sheep (b_B Group) and six-month-old Hu sheep (s_B Group) as the objects. MeRIP-seq and RNA-Seq analysis techniques were used to detect differentially methylated genes (DMGs) and differentially expressed genes (DEGs) in the longissimus dorsi muscle of Hu sheep at different months of age. Then, conjoint analysis was further employed to screen for key genes involved in skeletal muscle development that are modified by m6A and expressed by mRNA. According to the results of the MeRIP-seq analysis, there were 285 m6A differentially methylated peaks (DMPs) in total between b_B Group and s_B Group, with 192 significant upregulated peaks and 93 significant downregulated peaks. GO and KEGG analysis revealed that DMGs are mainly enriched in actin-binding, cellular transport, and metabolic pathways. According to the results of the RNA-seq analysis, there were 4,349 DEGs in total between b_B Group and s_B Group, with 2010 upregulated genes and 2,339 downregulated genes. DEGs are found to be mainly enriched in the regulation of actin cytoskeleton tissue, AMPK and FoxO signaling pathways, etc. The conjoint analysis demonstrated that 283 genes were both modified by m6A and expressed by mRNA. Among them, three genes relevant to muscle growth (RGMB, MAPK8IP3, and RSPO3) were selected as candidates for quantitative validation, and the results were in line with the sequencing results. The results mentioned above all suggest that m6A plays a certain role in the skeletal muscle development in Hu sheep.

Epigenetic Modifiers in Cancer Metastasis

Metastasis is the primary cause of cancer-related death, with the dissemination and colonization of primary tumor cells at the metastatic site facilitated by various molecules and complex pathways. Understanding the biological mechanisms underlying the metastatic process is critical for the development of effective interventions. Several epigenetic modifications have been identified that play critical roles in regulating cancer metastasis. This review aims to provide a comprehensive summary of recent advances in understanding the role of epigenetic modifiers, including histone modifications, DNA methylation, non-coding RNAs, enhancer reprogramming, chromatin accessibility, and N6-methyladenosine, in metastasis-associated processes, such as epithelial-mesenchymal transition (EMT), cancer cell migration, and invasion. In particular, this review provides a detailed and in-depth description of the role of crosstalk between epigenetic regulators in tumor metastasis. Additionally, we explored the potential and limitations of epigenetics-related target molecules in the diagnosis, treatment, and prognosis of cancer metastasis.

Nurturing gut health: role of m6A RNA methylation in upholding the intestinal barrier

The intestinal lumen acts as a critical interface connecting the external environment with the body's internal state. It's essential to prevent the passage of harmful antigens and bacteria while facilitating nutrient and water absorption. The intestinal barriers encompass microbial, mechanical, immunological, and chemical elements, working together to maintain intestinal balance. Numerous studies have associated m6A modification with intestinal homeostasis. This review comprehensively outlines potential mechanisms through which m6A modification could initiate, exacerbate, or sustain barrier damage from an intestinal perspective. The pivotal role of m6A modification in preserving intestinal equilibrium provides new insights, guiding the exploration of m6A modification as a target for optimizing preventive and therapeutic strategies for intestinal homeostasis.

Dynamic changes in RNA m6A and 5 hmC influence gene expression programs during macrophage differentiation and polarisation

RNA modifications are essential for the establishment of cellular identity. Although increasing evidence indicates that RNA modifications regulate the innate immune response, their role in monocyte-to-macrophage differentiation and polarisation is unclear. While m6A has been widely studied, other RNA modifications, including 5 hmC, remain poorly characterised. We profiled m6A and 5 hmC epitranscriptomes, transcriptomes, translatomes and proteomes of monocytes and macrophages at rest and pro- and anti-inflammatory states. Transcriptome-wide mapping of m6A and 5 hmC reveals enrichment of m6A and/or 5 hmC on specific categories of transcripts essential for macrophage differentiation. Our analyses indicate that m6A and 5 hmC modifications are present in transcripts with critical functions in pro- and anti-inflammatory macrophages. Notably, we also discover the co-occurrence of m6A and 5 hmC on alternatively-spliced isoforms and/or opposing ends of the untranslated regions (UTR) of mRNAs with key roles in macrophage biology. In specific examples, RNA 5 hmC controls the decay of transcripts independently of m6A. This study provides (i) a comprehensive dataset to interrogate the role of RNA modifications in a plastic system (ii) a resource for exploring different layers of gene expression regulation in the context of human monocyte-to-macrophage differentiation and polarisation, (iii) new insights into RNA modifications as central regulators of effector cells in innate immunity.

Distinctive tumorigenic significance and innovative oncology targets of SUMOylation

Protein SUMOylation, a post-translational modification, intricately regulates diverse biological processes including gene expression, cell cycle progression, signaling pathway transduction, DNA damage response, and RNA metabolism. This modification contributes to the acquisition of tumorigenicity and the maintenance of cancer hallmarks. In malignancies, protein SUMOylation is triggered by various cellular stresses, promoting tumor initiation and progression. This augmentation is orchestrated through its specific regulatory mechanisms and characteristic biological functions. This review focuses on elucidating the fundamental regulatory mechanisms and pathological functions of the SUMO pathway in tumor pathogenesis and malignant evolution, with particular emphasis on the tumorigenic potential of SUMOylation. Furthermore, we underscore the potential therapeutic benefits of targeting the SUMO pathway, paving the way for innovative anti-tumor strategies by perturbing this dynamic and reversible modifying process.

DNA methylation regulates RNA m6A modification through transcription factor SP1 during the development of porcine somatic cell nuclear transfer embryos

Epigenetic modifications play critical roles during somatic cell nuclear transfer (SCNT) embryo development. Whether RNA N6-methyladenosine (m6A) affects the developmental competency of SCNT embryos remains unclear. Here, we showed that porcine bone marrow mesenchymal stem cells (pBMSCs) presented higher RNA m6A levels than those of porcine embryonic fibroblasts (pEFs). SCNT embryos derived from pBMSCs had higher RNA m6A levels, cleavage, and blastocyst rates than those from pEFs. Compared with pEFs, the promoter region of METTL14 presented a hypomethylation status in pBMSCs. Mechanistically, DNA methylation regulated METTL14 expression by affecting the accessibility of transcription factor SP1 binding, highlighting the role of the DNA methylation/SP1/METTL14 pathway in donor cells. Inhibiting the DNA methylation level in donor cells increased the RNA m6A level and improved the development efficiency of SCNT embryos. Overexpression of METTL14 significantly increased the RNA m6A level in donor cells and the development efficiency of SCNT embryos, whereas knockdown of METTL14 suggested the opposite result. Moreover, we revealed that RNA m6A-regulated TOP2B mRNA stability, translation level, and DNA damage during SCNT embryo development. Collectively, our results highlight the crosstalk between RNA m6A and DNA methylation, and the crucial role of RNA m6A during nuclear reprogramming in SCNT embryo development.

Comprehensive analysis of m6 A methylome and transcriptome by Nanopore sequencing in clear cell renal carcinoma

N6 -methyladenosine (m6 A) is the most prevalent epigenetic modification on eukaryotic messenger RNAs. Recent studies have focused on elucidating the key role of m6 A modification patterns in tumor progression. However, the relationship between m6 A and transcriptional regulation remains elusive. Nanopore technology enables the quantification of m6 A levels at each genomic site. In this study, a pair of tumor tissues and adjacent normal tissues from clear cell renal cell carcinoma (ccRCC) surgical samples were collected for Nanopore direct RNA sequencing. We identified 9644 genes displaying anomalous m6 A modifications, with 5343 genes upregulated and 4301 genes downregulated. Among these, 5224 genes were regarded as dysregulated genes, encompassing abnormal regulation of both m6 A modification and RNA expression. Gene Set Enrichment Analysis revealed an enrichment of these genes in pathways related to renal system progress and fatty acid metabolic progress. Furthermore, the χ2 test demonstrated a significant association between the levels of m6 A in dysregulated genes and their transcriptional expression levels. Additionally, we identified four obesity-associated genes (FTO, LEPR, ADIPOR2, and NPY5R) among the dysregulated genes. Further analyses using public databases revealed that these four genes were all related to the prognosis and diagnosis of ccRCC. This study introduced the novel approach of employing conjoint analysis of m6 A modification and RNA expression based on Nanopore sequencing to explore potential disease-related genes. Our work demonstrates the feasibility of the application of Nanopore sequencing technology in RNA epigenetic regulation research and identifies new potential therapeutic targets for ccRCC.

m6A-dependent upregulation of DDX21 by super-enhancer-driven IGF2BP2 and IGF2BP3 facilitates progression of acute myeloid leukaemia

BACKGROUND

Acute myeloid leukaemia (AML) is a haematological malignancy with unfavourable prognosis. Despite the effectiveness of chemotherapy and targeted therapy, relapse or drug resistance remains a major threat to AML patients. N6-methyladenosine (m6A) RNA methylation and super-enhancers (SEs) are extensively involved in the leukaemogenesis of AML. However, the potential relationship between m6A and SEs in AML has not been elaborated.

METHODS

Chromatin immunoprecipitation (ChIP) sequencing data from Gene Expression Omnibus (GEO) cohort were analysed to search SE-related genes. The mechanisms of m6 A-binding proteins IGF2BP2 and IGF2BP3 on DDX21 were explored via methylated RNA immunoprecipitation (MeRIP) assays, RNA immunoprecipitation (RIP) assays and luciferase reporter assays. Then we elucidated the roles of DDX21 in AML through functional assays in vitro and in vivo. Finally, co-immunoprecipitation (Co-IP) assays, RNA sequencing and ChIP assays were performed to investigate the downstream mechanisms of DDX21.

RESULTS

We identified two SE-associated transcripts IGF2BP2 and IGF2BP3 in AML. High enrichment of H3K27ac, H3K4me1 and BRD4 was observed in IGF2BP2 and IGF2BP3, whose expression were driven by SE machinery. Then IGF2BP2 and IGF2BP3 enhanced the stability of DDX21 mRNA in an m6A-dependent manner. DDX21 was highly expressed in AML patients, which indicated a poor survival. Functionally, knockdown of DDX21 inhibited cell proliferation, promoted cell apoptosis and led to cell cycle arrest. Mechanistically, DDX21 recruited transcription factor YBX1 to cooperatively trigger ULK1 expression. Moreover, silencing of ULK1 could reverse the promoting effects of DDX21 overexpression in AML cells.

CONCLUSIONS

Dysregulation of SE-IGF2BP2/IGF2BP3-DDX21 axis facilitated the progression of AML. Our findings provide new insights into the link between SEs and m6A modification, elucidate the regulatory mechanisms of IGF2BP2 and IGF2BP3 on DDX21, and reveal the underlying roles of DDX21 in AML.

Overexpression of YTHDF3 increases the specific productivity of the recombinant protein in CHO cells by promoting the translation process

Due to their high-quality characteristics, Chinese hamster ovary (CHO) cells have become the most widely used and reliable host cells for the production of recombinant therapeutic proteins in the biomedical field. Previous studies have shown that the m6A reader YTHDF3, which contains the YTH domain, can affect a variety of biological processes by regulating the translation and stability of target mRNAs. This study investigates the effect of YTHDF3 on transgenic CHO cells. The results indicate that stable overexpression of YTHDF3 significantly enhances recombinant protein expression without affecting host cell growth. Transcriptome sequencing indicated that several genes, including translation initiation factor, translation extension factor, and ribosome assembly factor, were upregulated in CHO cells overexpressing YTHDF3. In addition, cycloheximide experiments confirmed that YTHDF3 enhanced transgene expression by promoting translation in CHO cells. In conclusion, the findings in this study provide a novel approach for mammalian cell engineering to increase protein productivity by regulating m6A.

RNA m6A modification facilitates DNA methylation during maize kernel development

N6-methyladenosine (m6A) in mRNA and 5-methylcytosine (5mC) in DNA have critical functions for regulating gene expression and modulating plant growth and development. However, the interplay between m6A and 5mC is an elusive territory and remains unclear mechanistically in plants. We reported an occurrence of crosstalk between m6A and 5mC in maize (Zea mays) via the interaction between mRNA adenosine methylase (ZmMTA), the core component of the m6A methyltransferase complex, and decrease in DNA methylation 1 (ZmDDM1), a key chromatin-remodeling factor that regulates DNA methylation. Genes with m6A modification were coordinated with a much higher level of DNA methylation than genes without m6A modification. Dysfunction of ZmMTA caused severe arrest during maize embryogenesis and endosperm development, leading to a significant decrease in CHH methylation in the 5' region of m6A-modified genes. Instead, loss of function of ZmDDM1 had no noteworthy effects on ZmMTA-related activity. This study establishes a direct link between m6A and 5mC during maize kernel development and provides insights into the interplay between RNA modification and DNA methylation.

Comprehensive analysis of aflatoxin B1 biosynthesis in Aspergillus flavus via transcriptome-wide m6A methylome response to cycloleucine

Aspergillus flavus and its toxic aflatoxins secondary metabolites contaminate food and grains, posing a severe threat to human health and leading to liver cancer. Here, we demonstrated that cycloleucine blocked aflatoxin B1 synthesis by inhibiting N6-methyladenosine (m6A) methylation modification of messenger RNA (mRNA). m6A Methylation Immunoprecipitation Sequencing (m6A MeRIP-Seq)-based comprehensive transcriptome-wide m6A profiling identified 102 differentially expressed genes that underwent m6A modification, of which 22 hypermethylated genes were downregulated and 49 hypomethylated genes were upregulated, suggesting a negative correlation between m6A methylation and gene expression. Notably, cycloleucine inhibited aflatoxin B1 production via multiple targets. The m6A sites of several key genes involved in the aflatoxin B1 biosynthesis pathway were significantly enriched in the coding sequence and around the stop codon, resulting in their downregulation. Furthermore, m6A methylation on genes related to the aflatoxin B1 biosynthesis pathway led to reduced mRNA stability. Cycloleucine inhibition of aflatoxin B1 production highlights its potential as an agent for removing mycotoxins in environmental pollution. ENVIRONMENTAL IMPLICATION: Aflatoxins, highly carcinogenic secondary metabolites produced by Aspergillus flavus, frequently contaminate crops such as peanut, corn, wheat and sesame leading to irreversible loss in the quality and yield of agricultural products and posing serious threats to food safety. Aflatoxins has also been linked to developmental delays and liver cancer in humans. In our study, 'monitoring aflatoxin concentrations and its bioaccumulation in organisms' has been conducted. The results demonstrated that aflatoxin production in A. flavus was completely blocked after cycloleucine treatment. Additionally, we demonstrated that inhibition of aflatoxin was linked to N6-methyladenosine methylation of multiple genes in aflatoxin biosynthesis pathway.

m6A modification patterns are associated with copy number burden and tumor immune landscape in thyroid cancer

BACKGROUND

The association involving N6-methyladenosine (m6A) modification, molecular subtype and specific immune cell group in tumor microenvironment has been the focus of recent studies. The underlying function of m6A modification in thyroid cancer (TC) remains elusive.

METHODS

The m6A modification regulations, molecular character and tumor immune profile of 461 TC patients were explored and then the correlation between them were comprehensively evaluated. The m6Ascore was established using principal component analysis (PCA) to quantify the m6A pattern of individual TC patients. The prognostic significance of the m6Ascore was evaluated by multivariate Cox regression analysis.

RESULTS

Four m6Aclusters (mc1, 2, 3, 4)-characterized by differences in extent of aneuploidy, expression of immunomodulatory genes, mRNA or lncRNA expression pattern and prognosis were identified. T Preliminary validation of m6Ascore was a potential independent prognostic factor of TC involving in mc3. Finally, the prognostic value of the m6Ascore and its association with copy number variation (CNV) and tumor immune microenvironment (TIME) of TC in mc3 were verified.

CONCLUSIONS

The correlation between m6A modification, the copy number burden and tumor immune landscape in TC was demonstrated. A m6Acluster-mc3 with low m6Ascore and high CNV molecular subtype was identified with poor clinical prognosis, low infiltrating immunocyte and weak effector T cell. A three-gene clinical prognosis model for TC based on 4 m6a cluster expression was established. Understanding of TIME is enhanced by comprehensive assessment of m6A patterns in individual TC patients and gives a new insight toward improved immunotherapy strategies for TC cancer patients.

Targeting N6-methyladenosine reader YTHDF1 with siRNA boosts antitumor immunity in NASH-HCC by inhibiting EZH2-IL-6 axis

BACKGROUND & AIMS

RNA N6-methyladenosine (m6A) reader protein YTHDF1 has been implicated in cancer; however, its role in hepatocellular carcinoma (HCC), especially in non-alcoholic steatohepatitis-associated HCC (NASH-HCC), remains unknown. Here, we investigated the functional role of YTHDF1 in NASH-HCC and its interplay with the tumor immune microenvironment.

METHODS

Hepatocyte-specific Ythdf1-overexpressing mice were subjected to a NASH-HCC-inducing diet. Tumor-infiltrating immune cells were profiled with single-cell RNA-sequencing, flow cytometry, and immunostaining. The molecular target of YTHDF1 was elucidated with RNA-sequencing, m6A-sequencing, YTHDF1 RNA immunoprecipitation-sequencing, proteomics, and ribosome-profiling. Ythdf1 in NASH-HCC models was targeted by lipid nanoparticle (LNP)-encapsulated small-interfering Ythdf1.

RESULTS

YTHDF1 is overexpressed in tumor tissues compared to adjacent peri-tumor tissues from patients with NASH-HCC. Liver-specific Ythdf1 overexpression drives tumorigenesis in dietary models of spontaneous NASH-HCC. Single-cell RNA-sequencing and flow cytometry revealed that Ythdf1 induced accumulation of myeloid-derived suppressor cells (MDSCs) and suppressed cytotoxic CD8+ T-cell function. Mechanistically, Ythdf1 expression in NASH-HCC cells induced the secretion of IL-6, which mediated MDSC recruitment and activation, leading to CD8+ T-cell dysfunction. EZH2 mRNA was identified as a key YTHDF1 target. YTHDF1 binds to m6A-modified EZH2 mRNA and promotes EZH2 translation. EZH2 in turn increased expression and secretion of IL-6. Ythdf1 knockout synergized with anti-PD-1 treatment to suppress tumor growth in NASH-HCC allografts. Furthermore, therapeutic targeting of Ythdf1 using LNP-encapsulated small-interfering RNA significantly increased the efficacy of anti-PD-1 blockade in NASH-HCC allografts.

CONCLUSIONS

We identified that YTHDF1 promotes NASH-HCC tumorigenesis via EZH2-IL-6 signaling, which recruits and activates MDSCs to cause cytotoxic CD8+ T-cell dysfunction. YTHDF1 may be a novel therapeutic target to improve responses to anti-PD-1 immunotherapy in NASH-HCC.

IMPACT AND IMPLICATIONS

YTHDF1, a N6-methyladenosine reader, is upregulated in patients with non-alcoholic steatohepatitis (NASH)-associated hepatocellular carcinoma (HCC); however, its role in modulating the tumor immune microenvironment in NASH-HCC remains unclear. Here, we show that Ythdf1 mediates immunosuppression in NASH-HCC and that targeting YTHDF1 in combination with immune checkpoint blockade elicits robust antitumor immune responses. Our findings suggest novel therapeutic targets for potentiating the efficacy of immune checkpoint blockade in NASH-HCC and provide the rationale for developing YTHDF1 inhibitors for the treatment of NASH-HCC.

Parental Exposure to Environmentally Relevant Concentrations of Bisphenol-A Bis(diphenyl phosphate) Impairs Vascular Development in Offspring through DNA/RNA Methylation-Dependent Transmission

Bisphenol-A bis(diphenyl phosphate) (BDP) has been increasingly detected in indoor environmental and human samples. Little is known about its developmental toxicity, particularly the intergenerational effects of parental exposure. In this study, adult zebrafish were exposed to BDP at 30-30,000 ng/L for 28 days, with results showing that exposure did not cause a transfer of BDP or its metabolites to offspring. Vascular morphometric profiling revealed that parental exposure to BDP at 30 and 300 ng/L exerted significant effects on the vascular development of offspring, encompassing diverse alterations in multiple types of blood vessels. N6-Methyladenosine (m6A) methylated RNA immunoprecipitation sequencing of larvae in the 300 ng/L group revealed 378 hypomethylated and 350 hypermethylated m6A peaks that were identified in mRNA transcripts of genes crucial for vascular development, including the Notch/Vegf signaling pathway. Concomitant changes in 5 methylcytosine (m5C) DNA methylation and gene expression of m6A modulators (alkbh5, kiaa1429, and ythdf1) were observed in both parental gonads and offspring exposed to BDP. These results reveal that parental exposure to low concentrations of BDP caused offspring vascular disorders by interfering with DNA and RNA methylation, uncovering a unique DNA-RNA modification pattern in the intergenerational transmission of BDP's developmental toxicity.

Unveiling the genetic and epigenetic landscape of colorectal cancer: new insights into pathogenic pathways

Colorectal cancer (CRC) is a complex disease characterized by genetic and epigenetic alterations, playing a crucial role in its development and progression. This review aims to provide insights into the emerging landscape of these alterations in CRC pathogenesis to develop effective diagnostic tools and targeted therapies. Genetic alterations in signaling pathways such as Wnt/β-catenin, and PI3K/Akt/mTOR are pivotal in CRC development. Genetic profiling has identified distinct molecular subtypes, enabling personalized treatment strategies. Epigenetic modifications, including DNA methylation and histone modifications, also contribute to CRC pathogenesis by influencing critical cellular processes through gene silencing or activation. Non-coding RNAs have emerged as essential players in epigenetic regulation and CRC progression. Recent research highlights the interplay between genetic and epigenetic alterations in CRC. Genetic mutations can affect epigenetic modifications, leading to dysregulated gene expression and signaling cascades. Conversely, epigenetic changes can modulate genetic expression, amplifying or dampening the effects of genetic alterations. Advancements in understanding pathogenic pathways have potential clinical applications. Identifying genetic and epigenetic markers as diagnostic and prognostic biomarkers promises more accurate risk assessment and early detection. Challenges remain, including validating biomarkers and developing robust therapeutic strategies through extensive research and clinical trials. The dynamic nature of genetic and epigenetic alterations necessitates a comprehensive understanding of their temporal and spatial patterns during CRC progression. In conclusion, the genetic and epigenetic landscape of CRC is increasingly being unraveled, providing valuable insights into its pathogenesis. Integrating genetic and epigenetic knowledge holds great potential for improving diagnostics, prognostics, and personalized therapies in CRC. Continued research efforts are vital to translate these findings into clinical practice, ultimately improving patient outcomes.

Regulatory role of N6-methyladenosine in intramuscular fat deposition in chicken

Intramuscular fat (IMF) has a pivotal influence on meat quality, with its deposition being a multifaceted physiological interaction of several regulatory factors. N6-methyladenosine (m6A), the preeminent epigenetic alteration among eukaryotic RNA modifications, holds a crucial role in moderating post-transcriptional gene expression. However, there is a dearth of comprehensive understanding regarding the functional machinery of m6A modification in the context of IMF deposition in poultry. Our current study entails an analysis of the disparities in IMF within the breast and leg of 180-day-old Jingyuan chickens. We implemented methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) to delve into the distribution of m6A and its putative regulatory frameworks on IMF deposition in chickens. The findings demonstrated a markedly higher IMF content in leg relative to breast (P < 0.01). Furthermore, the expression of METTL14, WTAP, FTO, and ALKBH5 was significantly diminished in comparison to that of breast (P < 0.01). The m6A peaks in the breast and leg primarily populated 3'untranslated regions (3'UTR) and coding sequence (CDS) regions. The leg, when juxtaposed with the breast, manifested 176 differentially methylated genes (DMGs), including 151 hyper-methylated DMGs and 25 hypo-methylated DMGs. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed a pronounced enrichment of DMGs in the biosynthesis of amino acids, peroxisome, Fatty acid biosynthesis, fatty acid elongation, and cell adhesion molecules (CAMs) pathways. Key DMGs, namely ECH1, BCAT1, and CYP1B1 were implicated in the regulation of muscle lipid anabolism. Our study offers substantial insight and forms a robust foundation for further exploration of the functional mechanisms of m6A modification in modulating IMF deposition. This holds profound theoretical importance for improving and leveraging meat quality in indigenous chicken breeds.

Microcystin-LR induces lactate production disruption via altering the m6A modification in Sertoli cells

We have previously reported the toxicity of microcystin-LR (MC-LR) to the male reproductive system, which results in functional changes in mouse testes. In this study, mice were orally exposed to MC-LR at 1, 7.5, 15, or 30 μg/L daily for 180 days. We found an increase in germ cell apoptosis in the seminiferous tubules and low-quality sperm in the epididymis. A decrease in lactate dehydrogenase A (Ldha) expression in testes through high-throughput sequencing was observed. We validated that MC-LR disrupted lactate production in Sertoli cells by suppressing the expression of Ldha. Further studies identified that methyltransferase 3 (Mettl3) catalysed N6-methyladenosine (m6A) methylation of Ldha mRNA. Mettl3 was downregulated in Sertoli cells following exposure to MC-LR, decreasing m6A levels of Ldha. The stability of Ldha mRNA decreased when m6A levels of Ldha were inhibited. In conclusion, these results showed that MC-LR inhibits the expression of Ldha in an m6A-dependent manner, which might result in the apoptosis of spermatogenic cells and a decline in sperm quality. Our work provides a new perspective to understanding MC-LR-induced male infertility.

Cell Differentiation and Aging Lead To Up-Regulation of FTO, While the ALKBH5 Protein Level Was Stable During Aging but Up-Regulated During in vitro-Induced Cardiomyogenesis

FTO and ALKBH5 proteins are essential erasers of N6-adenosine methylation in RNA. We studied how levels of FTO and ALKBH5 proteins changed during mouse embryonic development, aging, cardiomyogenesis, and neuroectodermal differentiation. We observed that aging in male and female mice was associated with FTO up-regulation in mouse hearts, brains, lungs, and kidneys, while the ALKBH5 level remained stable. FTO and ALKBH5 proteins were up-regulated during experimentally induced cardiomyogenesis, but the level of ALKBH5 protein was not changed when neuroectodermal differentiation was induced. HDAC1 depletion in mouse ES cells caused FTO down-regulation. In these cells, mRNA, carrying information from genes that regulate histone signature, RNA processing, and cell differentiation, was characterized by a reduced level of N6-adenosine methylation in specific gene loci, primarily regulating cell differentiation into neuroectoderm. Together, when we compared both RNA demethylating proteins, the FTO protein level undergoes the most significant changes during cell differentiation and aging. Thus, we conclude that during aging and neuronal differentiation, m6A RNA demethylation is likely regulated by the FTO protein but not via the function of ALKBH5.

Novel insight into RNA modifications in tumor immunity: Promising targets to prevent tumor immune escape

An immunosuppressive state is a typical feature of the tumor microenvironment. Despite the dramatic success of immune checkpoint inhibitor (ICI) therapy in preventing tumor cell escape from immune surveillance, primary and acquired resistance have limited its clinical use. Notably, recent clinical trials have shown that epigenetic drugs can significantly improve the outcome of ICI therapy in various cancers, indicating the importance of epigenetic modifications in immune regulation of tumors. Recently, RNA modifications (N⁶-methyladenosine [m⁶A], N¹-methyladenosine [m¹A], 5-methylcytosine [m⁵C], etc.), novel hotspot areas of epigenetic research, have been shown to play crucial roles in protumor and antitumor immunity. In this review, we provide a comprehensive understanding of how m⁶A, m¹A, and m⁵C function in tumor immunity by directly regulating different immune cells as well as indirectly regulating tumor cells through different mechanisms, including modulating the expression of immune checkpoints, inducing metabolic reprogramming, and affecting the secretion of immune-related factors. Finally, we discuss the current status of strategies targeting RNA modifications to prevent tumor immune escape, highlighting their potential.

Metabolic reprogramming and epigenetic modifications in cancer: from the impacts and mechanisms to the treatment potential

Metabolic reprogramming and epigenetic modifications are hallmarks of cancer cells. In cancer cells, metabolic pathway activity varies during tumorigenesis and cancer progression, indicating regulated metabolic plasticity. Metabolic changes are often closely related to epigenetic changes, such as alterations in the expression or activity of epigenetically modified enzymes, which may exert a direct or an indirect influence on cellular metabolism. Therefore, exploring the mechanisms underlying epigenetic modifications regulating the reprogramming of tumor cell metabolism is important for further understanding tumor pathogenesis. Here, we mainly focus on the latest studies on epigenetic modifications related to cancer cell metabolism regulations, including changes in glucose, lipid and amino acid metabolism in the cancer context, and then emphasize the mechanisms related to tumor cell epigenetic modifications. Specifically, we discuss the role played by DNA methylation, chromatin remodeling, noncoding RNAs and histone lactylation in tumor growth and progression. Finally, we summarize the prospects of potential cancer therapeutic strategies based on metabolic reprogramming and epigenetic changes in tumor cells.

Epigenetic modification of m6A regulator proteins in cancer

Divergent N6-methyladenosine (m6A) modifications are dynamic and reversible posttranscriptional RNA modifications that are mediated by m6A regulators or m6A RNA methylation regulators, i.e., methyltransferases ("writers"), demethylases ("erasers"), and m6A-binding proteins ("readers"). Aberrant m6A modifications are associated with cancer occurrence, development, progression, and prognosis. Numerous studies have established that aberrant m6A regulators function as either tumor suppressors or oncogenes in multiple tumor types. However, the functions and mechanisms of m6A regulators in cancer remain largely elusive and should be explored. Emerging studies suggest that m6A regulators can be modulated by epigenetic modifications, namely, ubiquitination, SUMOylation, acetylation, methylation, phosphorylation, O-GlcNAcylation, ISGylation, and lactylation or via noncoding RNA action, in cancer. This review summarizes the current roles of m6A regulators in cancer. The roles and mechanisms for epigenetic modification of m6A regulators in cancer genesis are segregated. The review will improve the understanding of the epigenetic regulatory mechanisms of m6A regulators.

Targeting m6A binding protein YTHDFs for cancer therapy

N⁶-methyladenosine (m⁶A) is the most common mRNA modification in mammalians. The function and dynamic regulation of m⁶A depends on the "writer", "readers" and "erasers". YT521-B homology domain family (YTHDF) is a class of m⁶A binding proteins, including YTHDF1, YTHDF2 and YTHDF3. In recent years, the modification of m⁶A and the molecular mechanism of YTHDFs have been further understood. Growing evidence has shown that YTHDFs participate in multifarious bioprocesses, particularly tumorigenesis. In this review, we summarized the structural characteristics of YTHDFs, the regulation of mRNA by YTHDFs, the role of YTHDF proteins in human cancers and inhibition of YTHDFs.

VIRMA Promotes Nasopharyngeal Carcinoma Tumorigenesis and Metastasis by Upregulation of E2F7 in an m6A-Dependent Manner

The N6-methyladenosine (m6A) modification possesses new and essential roles in tumor initiation and progression by regulating mRNA biology. However, the role of aberrant m6A regulation in nasopharyngeal carcinoma (NPC) remains unclear. Here, through comprehensive analyses of NPC cohorts from the GEO database and our internal cohort, we identified that VIRMA, an m6A writer, is significantly upregulated in NPC and plays an essential role in tumorigenesis and metastasis of NPC, both in vitro and in vivo. High VIRMA expression served as a prognostic biomarker and was associated with poor outcomes in patients with NPC. Mechanistically, VIRMA mediated the m6A methylation of E2F7 3'-UTR, then IGF2BP2 bound and maintained the stability of E2F7 mRNA. An integrative high-throughput sequencing approach revealed that E2F7 drives a unique transcriptome distinct from the classical E2F family in NPC, which functioned as an oncogenic transcriptional activator. E2F7 cooperated with CBFB-recruited RUNX1 in a non-canonical manner to transactivate ITGA2, ITGA5, and NTRK1, strengthening Akt signaling-induced tumor-promoting effect.

FTO demethylates m6A modifications in CDKAL1 mRNA and promotes gastric cancer chemoresistance by altering mitochondrial dynamics

N6-methyladenosine (m6A) modification is the most common mRNA modification that is considered a new layer of mRNA epigenetic regulation. Demethylase fat mass and obesity-associated protein (FTO) are important in the dynamic regulation of m6A, but their role in gastric cancer (GC) is not fully understood. This study revealed that FTO and CDKAL1 were up-regulated in GC cells and tissue. CDKAL1 is the downstream target of FTO-mediated m6A modification, with FTO promoting GC cell proliferation through CDKAL1 and inducing mitochondrial fusion, eventually causing GC chemoresistance. In conclusion, FTO contributes to the increasing resistance of GC cells to 5-fluorouracil (5-Fu) by upregulating CDKAL1 and inducing mitochondrial fusion.

Shiny transcriptional junk: lncRNA-derived peptides in cancers and immune responses

By interacting with DNA, RNA, and proteins, long noncoding RNAs (lncRNAs) have been linked to several pathological states. LncRNA-derived peptides, as a novel modality of action of lncRNAs, have recently become a research hotspot. An increasing body of evidence has demonstrated the important role of these peptides in carcinogenesis and cancer progression and immune response. This review first describes lncRNA-derived peptides, the regulators that control their translation, and the roles of these peptides in multiple biological processes and disease states including cancers. In the following section, we comprehensively analyzed the significant role lncRNA-derived peptide played in the immune response. This review provides fresh perspectives on the biological role of lncRNAs and their relationship with diseases, particularly with cancers and the immune response, providing a theoretical basis for these lncRNA-derived peptides as therapeutic and diagnostic targets in cancers and inflammatory diseases.

N6-Methyladenosine Methyltransferase METTL3 Alleviates Diabetes-Induced Testicular Damage through Modulating TUG1/Clusterin Axis

BACKGROUND

The present study investigated the regulatory effects of N6-methyladenosine (m6A) methyltransferase like-3 (METTL3) in diabetes-induced testicular damage.

METHODS

In vivo diabetic mice and high glucose (HG) treated GC-1 spg cells were established. The mRNA and protein expressions were determined by real-time quantitative polymerase chain reaction, Western blot, immunofluorescence and immunohistochemistry staining. Levels of testosterone, blood glucose, cell viability, and apoptosis were detected by enzyme-linked immunosorbent assay, MTT, and flow cytometry, respectively. Molecular interactions were verified by RNA immunoprecipitation and RNA pull-down assay. Histopathological staining was performed to evaluate testicular injury.

RESULTS

METTL3 and long non-coding RNA taurine up-regulated 1 (lncRNA TUG1) were downregulated in testicular tissues of diabetic mice and HG-treated GC-1 spg cells. METTL3 overexpression could reduce the blood glucose level, oxidative stress and testicular damage but enhance testosterone secretion in diabetic mouse model and HG-stimulated GC-1 spg cells. Mechanically, METTL3-mediated m6A methylation enhanced the stability of TUG1, then stabilizing the clusterin mRNA via recruiting serine and arginine rich splicing factor 1. Moreover, inhibition of TUG1/clusterin signaling markedly reversed the protective impacts of METTL3 overexpression on HG-stimulated GC-1 spg cells.

CONCLUSION

This study demonstrated that METTL3 ameliorated diabetes-induced testicular damage by upregulating the TUG1/clusterin signaling. These data further elucidate the potential regulatory mechanisms of m6A modification on diabetes-induced testicular injury.

Targeting RNA N6-methyladenosine to synergize with immune checkpoint therapy

Cancer immunotherapy, especially immune checkpoint therapy, has revolutionized therapeutic options by reactivating the host immune system. However, the efficacy varies, and only a small portion of patients develop sustained antitumor responses. Hence, illustrating novel strategies that improve the clinical outcome of immune checkpoint therapy is urgently needed. N6-methyladenosine (m⁶A) has been proved to be an efficient and dynamic posttranscriptional modification process. It is involved in numerous RNA processing, such as splicing, trafficking, translation and degradation. Compelling evidence emphasizes the paramount role of m⁶A modification in the regulation of immune response. These findings may provide a foundation for the rational combination of targeting m⁶A modification and immune checkpoints in cancer treatment. In the present review, we summarize the current landscape of m⁶A modification in RNA biology, and highlight the latest findings on the complex mechanisms by which m⁶A modification governs immune checkpoint molecules. Furthermore, given the critical role of m⁶A modification in antitumor immunity, we discuss the clinical significance of targeting m⁶A modification to improve the efficacy of immune checkpoint therapy for cancer control.

Epigenetic modifications: Allusive clues of lncRNA functions in plants

Long non-coding RNAs (lncRNAs) have been verified as flexible and important factors in various biological processes of multicellular eukaryotes, including plants. The respective intricate crosstalk among multiple epigenetic modifications has been examined to some extent. However, only a small proportion of lncRNAs has been functionally well characterized. Moreover, the relationship between lncRNAs and other epigenetic modifications has not been systematically studied. In this mini-review, we briefly summarize the representative biological functions of lncRNAs in developmental programs and environmental responses in plants. In addition, we particularly discuss the intimate relationship between lncRNAs and other epigenetic modifications, and we outline the underlying avenues and challenges for future research on plant lncRNAs.

Genetic and environmental reprogramming of the sarcoma epigenome

Sarcomas are rare and heterogenous mesenchymal tumors occurring in soft tissue and bone. The World Health Organization Classification of sarcomas comprises more than hundred different entities which are very diverse in their molecular, genetic and epigenetic signatures as they are in their clinical presentations and behaviors. While sarcomas can be associated with an underlying hereditary cancer predisposition, most sarcomas developed sporadically without identifiable cause. Sarcoma oncogenesis involves complex interactions between genetic, epigenetic and environmental factors which are intimately related and intensively studied. Several molecular discoveries have been made over the last decades leading to the development of new therapeutic avenues. Sarcoma research continues its effort toward a more specific and personalized approach to all sarcoma sub-types to improve patient outcomes and this through world-wide collaboration. This chapter on "Genetic and Environmental Reprogramming of the Sarcoma Epigenome" provides a comprehensive review of general concepts and epidemiology of sarcoma as well as a detailed description of the genetic, molecular and epigenetic alterations seen in sarcomas, their therapeutic implications and ongoing research. This review also presents evidenced-based data on the environmental and occupational factors possibly involved in the etiology of sarcomas and a brief discussion on the role of the microbiome in sarcoma.

Interplay of four types of RNA modification writers revealed distinct tumor microenvironment and biological characteristics in pancreatic cancer

Background

Pancreatic cancer (PC) is one of the most lethal malignancies and carries a dismal mortality and morbidity. Four types of RNA modification (namely m6A, m1A, APA and A-to-I) could be catalyzed by distinct enzymatic compounds ("writers"), mediating numerous epigenetic events in carcinogenesis and immunomodulation. We aim to investigate the interplay mechanism of these writers in immunogenomic features and molecular biological characteristics in PC.

Methods

We first accessed the specific expression pattern and transcriptional variation of 26 RNA modification writers in The Cancer Genome Atlas (TCGA) dataset. Unsupervised consensus clustering was performed to divide patients into two RNA modification clusters. Then, based on the differentially expressed genes (DEGs) among two clusters, RNA modification score (WM_Score) model was established to determine RNA modification-based subtypes and was validated in International Cancer Genome Consortium (ICGC) dataset. What's more, we manifested the unique status of WM_Score in transcriptional and post-transcriptional regulation, molecular biological characteristics, targeted therapies and immunogenomic patterns.

Results

We documented the tight-knit correlations between transcriptional expression and variation of RNA modification writers. We classified patients into two distinct RNA modification patterns (WM_Score_high and _low), The WM_Score_high subgroup was correlated with worse prognosis, Th2/Th17 cell polarization and oncogenic pathways (e.g. EMT, TGF-β, and mTORC1 signaling pathways), whereas the WM_Score_low subgroup associated with favorable survival rate and Th1 cell trend. WM_Score model also proved robust predictive power in interpreting transcriptional and post-transcriptional events. Additionally, the potential targeted compounds with related pathways for the WM_Score model were further identified.

Conclusions

Our research unfolds a novel horizon on the interplay network of four RNA modifications in PC. This WM_Score model demonstrated powerful predictive capacity in epigenetic, immunological and biological landscape, providing a theoretical basis for future clinical judgments of PC.

N6 -Methyladenosine-Modified CBX1 Regulates Nasopharyngeal Carcinoma Progression Through Heterochromatin Formation and STAT1 Activation

Epitranscriptomic remodeling such as N6 -methyladenosine (m6 A) modification plays a critical role in tumor development. However, little is known about the underlying mechanisms connecting m6 A modification and nasopharyngeal carcinoma (NPC) progression. Here, CBX1 is identified, a histone methylation regulator, to be significantly upregulated with m6 A hypomethylation in metastatic NPC tissues. The m6 A-modified CBX1 mRNA transcript is recognized and destabilized by the m6 A reader YTHDF3. Furthermore, it is revealed that CBX1 promotes NPC cell migration, invasion, and proliferation through transcriptional repression of MAP7 via H3K9me3-mediated heterochromatin formation. In addition to its oncogenic effect, CBX1 can facilitate immune evasion through IFN-γ-STAT1 signaling-mediated PD-L1 upregulation. Clinically, CBX1 serves as an independent predictor for unfavorable prognosis in NPC patients. The results reveal a crosstalk between epitranscriptomic and epigenetic regulation in NPC progression, and shed light on the functions of CBX1 in tumorigenesis and immunomodulation, which may provide an appealing therapeutic target in NPC.

Bioinformatics analysis of the correlation between m6A RNA methylation regulators and the immune infiltration and prognosis of bladder cancer

Background

To analyze the effect of N6-methyladenosine (m6A) RNA methylation regulators on the immune infiltration and prognosis of bladder cancer (BC). We explored the related signaling pathways and prognosis-related genes to provide candidate targets for the treatment and prognostic evaluation of BC.

Methods

After downloading BC data from The Cancer Genome Atlas (TCGA) database, the expressions of m6A-related genes were obtained. We then performed correlation and sample cluster analysis of the m6A methylation regulator genes as well as difference comparison and survival analysis for the clustered patients using R software. Gene set enrichment analysis (GSEA) was carried out on cluster-grouped samples. Finally, the prognosis-related genes of BC among the m6A methylation regulators were screened.

Results

Genomic alterations in the m6A regulators were linked to a poor BC prognosis. HNRNPA2B1, HNRNPC, IGF2BP2, RBM15, YTHDF1, and YTHDF2 were found to be associated with advanced clinical stages of BC. Furthermore, the current study revealed that the levels of the m6A regulators were related to the expression levels and immune infiltration levels of immune regulators [immunosuppressive factors, immunostimulators, and major histocompatibility complex (MHC) molecules] in BC. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses suggested that in addition to the relevant immune responses, m6A regulators were involved in the poor prognosis of BC via their participation in blood vessels through regulatory RNA binding, telomeric DNA binding, microRNA (miRNA) binding, negative regulation of messenger RNA (mRNA) processing, negative regulation of DNA biosynthesis, branches of morphogenesis, positive regulation of the Notch receptor target gene transcription, etc.

Conclusions

The expression of m6A RNA methylation regulators is closely linked to immune infiltration and prognosis in BC. Thus, it can be utilized as a potential molecular target for the treatment and prognostic assessment of BC.

Non-coding RNA and n6-methyladenosine modification play crucial roles in neuropathic pain

After peripheral nerve injury, pain signals are transmitted from primary sensory neurons in the dorsal root ganglion (DRG) to the central nervous system. Epigenetic modification affects neuropathic pain through alterations in the gene expression in pain-related areas and glial cell activation. Recent studies have shown that non-coding RNA and n6-methyladenosine (m6A) methylation modification play pivotal regulatory roles in the occurrence and maintenance of neuropathic pain. Dysregulation of the RNA m6A level via dynamic changes in methyltransferase and demethylase after central or peripheral nerve injury commonly regulates pain-associated genes, contributing to the induction and maintenance of neuropathic pain. The dynamic process has significant implications for the development and maintenance of neuropathic pain. However, the underlying mechanisms by which non-coding RNA and m6A RNA modification regulate neuropathic pain are not well-characterized. This article elucidates the multiple mechanisms of non-coding RNA and m6A methylation in the context of neuropathic pain, and summarizes its potential functions as well as recent advances.

Covalent RNA modifications and their budding crosstalk with plant epigenetic processes

Our recent cognizance of diverse RNA classes undergoing dynamic covalent chemical modifications (or epitranscriptomic marks) in plants has provided fresh insight into the underlying molecular mechanisms of gene expression regulation. Comparatively, epigenetic marks comprising heritable modifications of DNA and histones have been extensively studied in plants and their impact on plant gene expression is quite established. Based on our growing knowledge of the plant epitranscriptome and epigenome, it is logical to explore how the two regulatory layers intermingle to intricately determine gene expression levels underlying key biological processes such as development and response to stress. Herein, we focus on the emerging evidence of crosstalk between the plant epitranscriptome with epigenetic regulation involving DNA modification, histone modification, and non-coding RNAs.

Impact of N6-methyladenosine (m6A) modification on immunity

N6-methyl-adenosine (m⁶A) is the most prevalent modification on mRNAs and long noncoding RNAs (lnRNAs) in higher eukaryotes. Modulation of m⁶A relies on m⁶A writers, erasers and readers. m⁶A modification contributes to diverse fundamental biological functions at the molecular, cellular, and physiological levels. The dysregulation of m⁶A modification has been implicated in various human diseases. Thus, m⁶A modification has now become a research hotspot for its potential therapeutic applications in the treatment of various cancers and diseases. The immune system is essential to provide defense against infections and cancers. This review summarizes the current knowledge about the roles of m⁶A in regulating immune cell functions and immune responses.

The Epitranscriptome in miRNAs: Crosstalk, Detection, and Function in Cancer

The epitranscriptome encompasses all post-transcriptional modifications that occur on RNAs. These modifications can alter the function and regulation of their RNA targets, which, if dysregulated, result in various diseases and cancers. As with other RNAs, miRNAs are highly modified by epitranscriptomic modifications such as m6A methylation, 2'-O-methylation, m5C methylation, m7G methylation, polyuridine, and A-to-I editing. miRNAs are a class of small non-coding RNAs that regulates gene expression at the post-transcriptional level. miRNAs have gathered high clinical interest due to their role in disease, development, and cancer progression. Epitranscriptomic modifications alter the targeting, regulation, and biogenesis of miRNAs, increasing the complexity of miRNA regulation. In addition, emerging studies have revealed crosstalk between these modifications. In this review, we will summarize the epitranscriptomic modifications-focusing on those relevant to miRNAs-examine the recent crosstalk between these modifications, and give a perspective on how this crosstalk expands the complexity of miRNA biology.

Lipid metabolism and m6A RNA methylation are altered in lambs supplemented rumen-protected methionine and lysine in a low-protein diet

Background

Methionine or lysine has been reported to influence DNA methylation and fat metabolism, but their combined effects in N6-methyl-adenosine (m⁶A) RNA methylation remain unclarified. The combined effects of rumen-protected methionine and lysine (RML) in a low-protein (LP) diet on lipid metabolism, m⁶A RNA methylation, and fatty acid (FA) profiles in the liver and muscle of lambs were investigated. Sixty-three male lambs were divided into three treatment groups, three pens per group and seven lambs per pen. The lambs were fed a 14.5% crude protein (CP) diet (adequate protein [NP]), 12.5% CP diet (LP), and a LP diet plus RML (LP + RML) for 60 d.

Results

The results showed that the addition of RML in a LP diet tended to lower the concentrations of plasma leptin (P = 0.07), triglyceride (P = 0.05), and non-esterified FA (P = 0.08). Feeding a LP diet increased the enzyme activity or mRNA expression of lipogenic enzymes and decreased lipolytic enzymes compared with the NP diet. This effect was reversed by supplementation of RML with a LP diet. The inclusion of RML in a LP diet affected the polyunsaturated fatty acids (PUFA), n-3 PUFA, and n-6 PUFA in the liver but not in the muscle, which might be linked with altered expression of FA desaturase-1 (FADS1) and acetyl-CoA carboxylase (ACC). A LP diet supplemented with RML increased (P < 0.05) total m⁶A levels in the liver and muscle and were accompanied by decreased expression of fat mass and obesity-associated protein (FTO) and alkB homologue 5 (ALKBH5). The mRNA expressions of methyltransferase-like 3 (METTL3) and methyltransferase-like 14 (METTL14) in the LP + RML diet group were lower than those in the other two groups. Supplementation of RML with a LP diet affected only liver YTH domain family (YTHDF2) proteins (P < 0.05) and muscle YTHDF3 (P = 0.09), which can be explained by limited m⁶A-binding proteins that were mediated in mRNA fate.

Conclusions

Our findings showed that the inclusion of RML in a LP diet could alter fat deposition through modulations of lipogenesis and lipolysis in the liver and muscle. These changes in fat metabolism may be associated with the modification of m⁶A RNA methylation.

Graphical abstract

A systematic graph illustrates the mechanism of dietary methionine and lysine influence on lipid metabolism and M⁶A. The green arrow with triangular heads indicates as activation and brown-wine arrows with flat heads indicates as suppression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-022-00733-z.

Identification and Verification of m7G Modification Patterns and Characterization of Tumor Microenvironment Infiltration via Multi-Omics Analysis in Clear Cell Renal Cell Carcinoma

The epigenetic modification of tumorigenesis and progression in neoplasm has been demonstrated in recent studies. Nevertheless, the underlying association of N7-methylguanosine (m⁷G) regulation with molecular heterogeneity and tumor microenvironment (TME) in clear cell renal cell carcinoma (ccRCC) remains unknown. We explored the expression profiles and genetic variation features of m⁷G regulators and identified their correlations with patient outcomes in pan-cancer. Three distinct m⁷G modification patterns, including MGCS1, MGCS2, and MGCS3, were further determined and systematically characterized via multi-omics data in ccRCC. Compared with the other two subtypes, patients in MGCS3 exhibited a lower clinical stage/grade and better prognosis. MGCS1 showed the lowest enrichment of metabolic activities. MGCS2 was characterized by the suppression of immunity. We then established and validated a scoring tool named m7Sig, which could predict the prognosis of ccRCC patients. This study revealed that m⁷G modification played a vital role in the formation of the tumor microenvironment in ccRCC. Evaluating the m⁷G modification landscape helps us to raise awareness and strengthen the understanding of ccRCC’s characterization and, furthermore, to guide future clinical decision making.

3'untranslated regions of tumor suppressor genes evolved specific features to favor cancer resistance

Cancer-related genes have evolved specific genetic and genomic features to favor tumor suppression. Previously we reported that tumor suppressor genes (TSGs) acquired high promoter CpG dinucleotide frequencies during evolution to maintain high expression in normal tissues and resist cancer-specific downregulation. In this study, we investigated whether 3'untranslated regions (3'UTRs) of TSGs have evolved specific features to carry out similar functions. We found that 3'UTRs of TSGs, especially those involved in multiple histological types and pediatric cancers, are longer than those of non-cancer genes. 3'UTRs of TSGs also exhibit higher density of binding sites for RNA-binding proteins (RBPs), particularly those having high affinities to C-rich motifs. Both longer 3'UTR length and RBP binding sites enrichment are correlated with higher gene expression in normal tissues across tissue types. Moreover, both features together with the correlated N⁶-methyladenosine modification and the extent of protein-protein interactions are positively associated with the ability of TSGs to resist cancer-specific downregulation. These results were successfully validated with independent datasets. Collectively, these findings indicate that TSGs have evolved longer 3'UTR with increased propensity to RBP binding, N⁶-methyladenosine modification and protein-protein interactions for optimizing their tumor-suppressing functions.

Crosstalk of Histone and RNA Modifications Identified a Stromal-Activated Subtype with Poor Survival and Resistance to Immunotherapy in Gastric Cancer

Emerging evidence has revealed the pivotal role of epigenetic modifications in shaping the tumor microenvironment (TME). However, crosstalk between different modification types and their clinical relevance in cancers remain largely unexplored. In this study, using ChIP/MeRIP-seq data of seven human gastric cell lines, we systematically characterized the crosstalk of four epigenetic modification types including H3K4me1, H3K4me3, H3K27ac, and N6-methyladenosine (m6A) and identified a recurrent subtype with high FTO expression and low HDAC1 expression across three independent gastric cancer (GC) cohorts, which we named the epigenetic-modification-dysregulated (EMD) subtype. Patients of the EMD subtype were featured with poor survival, stromal activation, and immune suppression. Extensive relevance to clinical characteristics was observed in the EMD subtype, including the Lauren classification, MSI status, histological grade, TNM stage, the Asian Cancer Research Group classification, and the immune/fibrotic classification. An EMD score was then constructed using WGCNA and ssGSEA algorithms, to precisely recognize the EMD subtype and indicate prognosis and response to immunotherapy in multiple independent GC cohorts. Correlations of the EMD score with tumor mutation burden, tumor purity, aneuploidy score, tumorigenic pathways, TME characteristics, and FTO/HDAC1 ratio were measured. In vitro experiments were performed to demonstrate the correlation between FTO and the epithelial–mesenchymal transition pathway, which suggested FTO as a targetable vulnerability for GC patients with a high EMD score. Altogether, by comprehensively analyzing the epigenetic modification patterns of 1518 GC patients, we identified a novel stromal-activated subtype with poor survival and resistance to immunotherapy, which might benefit from the combined immune checkpoint inhibition therapy with FTO inhibition.

m6A RNA Methylation Regulators Contribute to Predict and as a Therapy Target of Pulmonary Fibrosis

Background

Pulmonary fibrosis is difficult to treat. Early diagnosis and finding potential drug therapy targets of pulmonary fibrosis are particularly important. There were still various problems with existing pulmonary fibrosis markers, so it is particularly important to find new biomarkers and drug treatment targets. m6A (N6,2'-O-dimethyladenosine) RNA methylation was the cause of many diseases, and it is regulated by m6A methylation regulators. So, whether RNA methylation regulators can be a diagnostic marker and potential drug therapy target of early pulmonary fibrosis needs to be explored.

Materials and Methods

Using GSE110147 and GSE33566 in the GEO database to predict the m6A methylation regulators that may be related to the development of pulmonary fibrosis, we used 10 mg/ml bleomycin to induce mouse pulmonary fibrosis models and human pulmonary fibrosis samples, to confirm whether this indicator can be an early diagnostic marker of pulmonary fibrosis.

Results

According to the database prediction results, METTL3 can predict the occurrence and development of pulmonary fibrosis, and the results of MASSON and HE staining show that the fibrosis model of mice is successful, and the fibrosis of human samples is obvious. The results of immunohistochemistry showed that the expression of METTL3 was significantly reduced in pulmonary fibrosis.

Conclusions

The m6A methylation regulator METTL3 can be considered as an important biomarker for diagnosing pulmonary fibrosis occurrence, furthermore it could be considered as a drug target because of its low expression in pulmonary fibrosis.

HLA complex P5 upregulation is correlated with poor prognosis and tumor progression in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a deadly malignant tumor that threatens human health. Long noncoding RNA (lncRNA) is widely expressed in eukaryotes and is closely associated with human disease progression. However, its role in ESCC remains incompletely understood. In this study, we analyzed the results of three gene expression omnibus (GEO) databases containing lncRNA expression data of ESCC and normal tissues. The results showed that HCP5 was significantly overexpressed in ESCC tissues, which was further verified in our collected ESCC samples. The functional study suggested that HCP5 knockdown inhibited ESCC cell proliferation and invasion. Regarding the mechanism, HCP5 was able to directly interact with YTHDF1, a N6-methyladenosine (m⁶A) reader, enhancing the binding of YTHDF1 to m⁶A-modified HK2 mRNA, leading to increasing HK2 stability, thereby promoting the Warburg effect (aerobic glycolysis) of ESCC cells. The nude mice model showed that the knockdown of HCP5 in vivo remarkably reduced tumor size. Clinically, high HCP5 was positively correlated with larger tumor volume, higher TNM stage and lymph node metastasis. Moreover, ESCC patients with high HCP5 exerted shorter survival time than patients with low HCP5. These findings uncover the importance of HCP5 in human ESCC progression; the turbulence of HCP5/YTHDF1/HK2 axis may be responsible for ESCC carcinogenicity.