CRISPR/dCas13(Rx) Derived RNA N6-methyladenosine (m6A) Dynamic Modification in Plant.

N6-methyladenosine (m6A) is the most prevalent internal modification of mRNA and plays an important role in regulating plant growth. However, there is still a lack of effective tools to precisely modify m6A sites of individual transcripts in plants. Here, programmable m6A editing tools are developed by combining CRISPR/dCas13(Rx) with the methyltransferase GhMTA (Targeted RNA Methylation Editor, TME) or the demethyltransferase GhALKBH10 (Targeted RNA Demethylation Editor, TDE). These editors enable efficient deposition or removal of m6A modifications at targeted sites of endo-transcripts GhECA1 and GhDi19 within a broad editing window ranging from 0 to 46 nt. TDE editor significantly decreases m6A levels by 24%-76%, while the TME editor increases m6A enrichment, ranging from 1.37- to 2.51-fold. Furthermore, installation and removal of m6A modifications play opposing roles in regulating GhECA1 and GhDi19 mRNA transcripts, which may be attributed to the fact that their m6A sites are located in different regions of the genes. Most importantly, targeting the GhDi19 transcript with TME editor plants results in a significant increase in root length and enhanced drought resistance. Collectively, these m6A editors can be applied to study the function of specific m6A modifications and have the potential for future applications in crop improvement.

The role of m6A modified circ0049271 induced by MNNG in precancerous lesions of gastric cancer.

Gastric cancer (GC) is a malignant cancer with the highest global rates of morbidity and death. Dietary factors have a close relationship with the occurrence of GC. Circular RNAs (circRNAs) and N6-methyladenine (m6A) are important factors in the onset and progression of GC and other malignancies. However, little is known about the role of circRNA m6A modifications in the occurrence and development of GC. Initially, a transformed malignant cell model generated by the chemical carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was established in this investigation. Furthermore, following exposure to MNNG, circ0049271 is substantially expressed in gastric epithelial cells (GES-1). Subsequent research revealed that the knockdown of circ0049271 prevented the epithelial-mesenchymal transition (EMT) as well as the migration, invasion, and proliferation of gastric epithelial cells induced by long-term exposure to MNNG. The opposite effects were observed when circ0049271 was overexpressed. Mechanistically, circ0049271 activates the TGFß/SMAD signaling pathway and has m6A modifications mediated by WTAP. Our findings indicate that circ0049271 promotes the occurrence of GC by regulating the TGFß/SMAD pathway, and WTAP may mediate the methylation of circ0049271 m6A. This study provides new insights into the regulation of circRNA-mediated m6A modifications and the discovery of early GC induced by dietary factors such as nitrite.

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.

The role of RNA m6A demethylase ALKBH5 in the mechanisms of fibrosis.

ALKBH5 is one of the demethylases involved in the regulation of RNA m6A modification. In addition to its role in the dynamic regulation of RNA m6A modification, ALKBH5 has been found to play important roles in various tissues fibrosis processes in recent years. However, the mechanisms and effects of ALKBH5 in fibrosis have been reported inconsistently. Multiple cell types, including parenchymal cells, immune cells (neutrophils and T cells), macrophages, endothelial cells, and fibroblasts, play roles in various stages of fibrosis. Therefore, this review analyzes the mechanisms by which ALKBH5 regulates these cells, its impact on their functions, and the outcomes of fibrosis. Furthermore, this review summarizes the role of ALKBH5 in fibrotic diseases such as pulmonary fibrosis, liver fibrosis, cardiac fibrosis, and renal fibrosis, and discusses various ALKBH5 inhibitors that have been discovered to date, exploring the potential of ALKBH5 as a clinical target for fibrosis.

ZC3H13 knockdown enhances the inhibitory effect of sevoflurane on gastric cancer cell malignancy by regulating the N6-methyladenosine modification of the lncRNA DLX6-AS1.

Sevoflurane, an inhalation anesthetic, has been shown to suppress cancer development. In this study, we investigated the specific mechanisms involving sevoflurane, zinc-finger CCCH-type containing 13 (ZC3H13), and lncRNA DLX6-AS1 in gastric cancer (GC) progression, focusing on the N6-methyladenosine (m6A) modification of long non-coding RNAs (lncRNAs). We used quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analyses to measure the levels of ZC3H13 and lncRNA DLX6-AS1 in GC tissues and cells. Furthermore, we conducted Cell Counting Kit-8, colony formation, Transwell, and tumor xenograft assays to evaluate changes in GC cell malignancy following cell transfection and sevoflurane treatment. Additionally, actinomycin D, methylated RNA immunoprecipitation, and qRT-PCR assays were performed to examine the regulatory effects of ZC3H13 on the DLX6-AS1 m6A modification. We detected elevated levels of ZC3H13 in GC samples, while ZC3H13 silencing inhibited GC cell proliferation, migration, and invasion. Silencing ZC3H13 also enhanced the inhibitory effects of sevoflurane on GC cell malignancy. Moreover, we found that the increased expression of DLX6-AS1 in GC cells could be suppressed by ZC3H13 through the mediation of the m6A modification of DLX6-AS1, thereby reducing DLX6-AS1 stability. In conclusion, ZC3H13 knockdown enhances the inhibitory effect of sevoflurane on GC cell malignancy by inducing DLX6-AS1 m6A modification. Our findings may help identify potential therapeutic targets for the treatment of GC.

METTL3-Driven m6A Modification of RBPJ Promotes Vascular Remodeling in Pulmonary Hypertension.

The dysregulation of N6-methyladenosine (m6A) RNA modification is widely recognized for its crucial roles in various diseases, including pulmonary hypertension (PH). Prior studies have highlighted the significant role of METTL3 in the pathogenesis of PH. Nevertheless, the potential and underlying mechanisms of METTL3 and its inhibitors as targets for PH treatment require further elucidation. In this study, we observed increased levels of METTL3 in various rodent models of PH. In vitro studies revealed that METTL3 silencing or treatment with STM2457, a specific METTL3 inhibitor, attenuated the proliferation and migration of pulmonary artery smooth muscle cells (PASMCs) stimulated by platelet-derived growth factor-BB (PDGF-BB) or hypoxia. Moreover, in vivo experiments using AAV9-mediated METTL3 silencing or STM2457 inhibition demonstrated improvement in SU5416/hypoxia-induced PH in mice. Additionally, m6A RNA immunoprecipitation analysis identified RBPJ as a gene regulated by METTL3 in rodent models of PH. Loss-of-function studies showed that silencing RBPJ could attenuate the changes in the proliferation and migration of PASMCs induced by PDGF-BB or hypoxia. Further studies indicated that METTL3 and YTHDF1 regulate RBPJ mRNA expression in an m6A-dependent manner. These findings indicated that targeting METTL3 may be a promising therapeutic strategy for treating PH, and modulation of RBPJ could offer a potential intervention mechanism.

ALKBH5-mediated m6A demethylation ameliorates extracellular matrix deposition in cutaneous pathological fibrosis.

BACKGROUND: Elevated extracellular matrix (ECM) accumulation is a major contributing factor to the pathogenesis of fibrotic diseases. Recent studies have indicated that N6-methyladenosine (m6A) RNA modification plays a pivotal role in modulating RNA stability and contribute to the initiation of various pathological conditions. Howbeit, the precise mechanism by which m6A influences ECM deposition remains unclear. METHODS: In this study, we used hypertrophic scars (HTSs) as a paradigm to investigate ECM-related diseases. We focused on the role of ALKBH5-mediated m6A demethylation within the pathological progression of HTSs and examined its correlation with clinical stages. The effects of ALKBH5 ablation on ECM components were studied both in vivo and in vitro. Downstream targets of ALKBH5, along with their underlying mechanisms, were identified using integrated high-throughput analysis, RNA-binding protein immunoprecipitation and RNA pull-down assays. Furthermore, the therapeutic potential of exogenous ALKBH5 overexpression was evaluated in fibrotic scar models. RESULTS: ALKBH5 was decreased in fibroblasts derived from HTS lesions and was negatively correlated with their clinical stages. Importantly, ablation of ALKBH5 promoted the expression of COL3A1, COL1A1, and ELN, leading to pathological deposition and reconstruction of the ECM both in vivo and in vitro. From a therapeutic perspective, the exogenous overexpression of ALKBH5 significantly inhibited abnormal collagen deposition in fibrotic scar models. As determined by integrated high-throughput analysis, key ECM components including COL3A1, COL1A1, and ELN are direct downstream targets of ALKBH5. By means of its mechanism, ALKBH5 inhibits the expression of COL3A1, COL1A1, and ELN by removing m6A from mRNAs, thereby decreasing their stability in a YTHDF1-dependent manner. CONCLUSIONS: Our study identified ALKBH5 as an endogenous suppressor of pathological ECM deposition, contributing to the development of a reprogrammed m6A-targeted therapy for HTSs.

m6A-Dependent ITIH1 Regulated by TGF-ß Acts as a Target for Hepatocellular Carcinoma Progression.

Both the transforming growth factor beta (TGF-ß) signaling pathway and N6-methyladenosine (m6A) modification for mRNA play an important role in hepatocellular carcinoma (HCC) progression. However, the relationship between TGF-ß and m6A in hepatocellular carcinoma (HCC) remains unclear. Here, it is found that TGF-ß can promote the liquid phase separation of METTL3, which further leads to the reduction of mRNA stability of ITIH1. As a secreted protein, ITIH1 can act as a ligand of integrin α5ß1 to antagonize fibronectin, induce the inhibition of focal adhesion kinase signaling pathway, and inhibit the progression of HCC. In the preclinical model (mouse model, patient-derived organoid, patient-derived xenografts), purified recombinant ITIH1 (r-ITIH1) protein can be targeted for HCC. More importantly, r-ITIH1 can play a synergistic role in targeting HCC with TGF-ß inhibitor. The downstream ITIH1 regulatory mechanism of TGF-ß and m6A modification is revealed, and ITIH1 can be translational as a potential target for HCC.

N6-methyladenosine enhances the expression of TGF-ß-SMAD signaling family to inhibit cell growth and promote cell metastasis.

TGF-ß-SMAD signaling pathway plays an important role in the progression of various cancers. However, posttranscriptional regulation such as N6-methyladenosine (m6A) of TGF-ß-SMAD signaling axis remains incompletely understood. Here, we reveal that insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2) is low expression as well as associated with poor prognosis in clear cell renal cell carcinoma (ccRCC) patients and inhibits proliferation as well as promotes metastasis of ccRCC cells. Mechanistically, IGF2BP2 systematically regulates TGF-ß-SMAD signaling family, including TGF-ß1/2, TGF-ßR1/2 and SMAD2/3/4, through mediating their mRNA stability in an m6A-dependent manner. Furthermore, the functional effects of IGF2BP2 on ccRCC cells is mediated by TGF-ß-SMAD signaling downstream effector SMAD4, which is identified three m6A sites in 5'UTR and CDS. Our study establishes IGF2BP2-TGF-ß-SMAD axis as a new regulatory effector in ccRCC, providing new insights for developing novel therapeutic strategies.

New insights into the dynamics of m6A epitranscriptome: hybrid-seq identifies novel mRNAs of the m6A writers METTL3/14.

Background: N6-methyladenosine (m6A), a prevalent mRNA modification, is dynamically regulated by methyltransferases, including METTL3 and METTL14.Materials & methods: In the current study, we employed a custom hybrid-seq method to identify novel METTL3/14 transcripts, explore their protein-coding capacities and predict the putative role of the METTL isoforms.Results: Demultiplexing of the hybrid-seq barcoded datasets unraveled the expression patterns of the newly identified mRNAs in major malignancies as well as in non-malignant cells, providing a deeper understanding of the methylation pathways. Open reading frame query revealed novel METTL3/14 isoforms, broadening our perspective for the structural diversity within METTL family.Conclusion: Our findings offer significant insights into the intricate transcriptional landscape of METTL3/14, shedding light on the regulatory mechanisms underlying methylation in mRNAs.

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RNA m6A methylation at the juxtaposition of apoptosis and RNA therapeutics.

Targeting RNA m6A marks in apoptosis-related transcripts holds promise for RNA therapeutics. However, pathway-specific RNA m6A sites on pro- or antiapoptotic transcripts have not been fully unveiled, let alone characterized. This article summarizes the current knowledge and gaps in the cellular response modulated by apoptotic stimulus-specific RNA m6A marks.

METTL3-STAT5B interaction facilitates the co-transcriptional m6A modification of mRNA to promote breast tumorigenesis.

Enhanced expression of methyltransferase-like 3 (METTL3) promotes the m6A modification of specific mRNAs, contributing to breast tumorigenesis. While the mRNA substrates targeted by METTL3 are well characterized, the factors dictating the selection of these specific mRNA remain elusive. This study aimed to examine the regulatory role of the transcription factor STAT5B in METTL3-induced m6A modification. METTL3 specifically interacts with STAT5B in response to mitogenic stimulation by epidermal growth factor (EGF). Chromatin immunoprecipitation and CRISPR/Cas9 mutagenesis showed that STAT5B recruits METTL3 to gene promoters like CCND1, where METTL3 interacts with RPB1, dependent on CDK9-mediated RPB1 (Ser2) phosphorylation during transcription elongation. Inhibition and depletion of either STAT5B or CDK9 prevented the EGF-induced m6A modification of CCND1. The translation efficiency of CCND1 was increased following m6A modification, thereby increasing cell proliferation. STAT5B facilitated METTL3-induced tumor formation by increasing CCND1 expression in an orthotopic mouse model. In clinical context, a positive correlation was observed between p-STAT5B and METTL3 expression in high-grade breast tumors. This study elucidates a novel mechanism that underlies the specificity of m6A modification in breast cancer cells, thereby underscoring its potential therapeutic value.

FTO promotes the progression of bladder cancer via demethylating m6A modifications in PTPN6 mRNA.

Bladder cancer (BC), a highly prevalent malignancy of the urinary system, necessitates further investigation into its progression mechanisms. N6-methyladenosine (m6A) RNA methylation, a prevalent modification in cellular RNA, has been implicated in the tumorigenesis and metastasis of various cancers. In this study, the upregulation of FTO in human BC samples and its association with poor prognosis were demonstrated using immunohistochemistry (IHC) on tissue sections collected from BC patients. The functional role of FTO in promoting the proliferation and metastasis abilities of BC cells was determined using a combination of in vitro and in vivo assays. In vitro, we conducted cell proliferation assays, such as the Cell Counting Kit-8 (CCK-8) assay, and metastasis assays, including the wound healing assay and transwell invasion assay. In vivo, we employed xenograft models to assess tumor growth and metastasis. Furthermore, our investigation into potential FTO targets in BC cells revealed that FTO modifies PTPN6 mRNA, leading to increased stability and expression of PTPN6, thereby enhancing proliferation and metastasis abilities. In conclusion, our findings indicate that FTO serves as an oncogenic factor in BC, suggesting its potential utility as a diagnostic or prognostic biomarker for bladder cancer.

METTL14 inhibits the proliferation, migration and invasion of prostate cancer cells by increasing m6A methylation of CDK4.

Background: Methyltransferase-like (METTL) plays an important role in various biological processes, but its role in prostate cancer (PCa) is still unclear. This study aimed to explore the mechanism by which methyltransferase-like 14 (METTL14) inhibits the physiological activity of PCa cells by increasing the N6-methyladenosine (m6A) modification of cyclin-dependent kinase 4 (CDK4). Methods: Clinical samples were collected for bioinformatics analysis. A PCa mouse model was constructed. Cell counting kit-8 (CCK-8), flow cytometry, colony formation assays, scratch assays, Transwell assays, real-time quantitative polymerase chain reaction (RT-qPCR), immunofluorescence and western blotting were used to detect the corresponding indicators. Results: METTL14 was found to be beneficial to inhibit the proliferation, invasion, and migration of PCa cells. When the m6A RNA increased, the half-life of CDK4 mRNA decreased after oe-METTL14 (overexpression of METTL14). Overexpression of CDK4 reversed the effect of oe-METTL14. Coimmunoprecipitation experiments revealed there were interactions between CDK4 and forkhead box M1 (FOXM1). Transfection of si-CDK4 was similar to transfection of oe-METTL14. After transfection with oe-FOXM1, the invasion and migration ability of cells increased, and cell apoptosis decreased. After transfection with si-FOXM1 alone, autophagy related 7 (ATG7) expression was significantly downregulated, and autophagy levels were reduced. The overexpression of ATG7 reversed the effect of si-FOXM1. The tumor volume and weight of the oe-METTL14 group mice were significantly reduced, and tumor proliferation was decreased in comparison to untreated tumor-bearing mice. Conclusions: METTL14 inhibits the invasion and migration of PCa cells and induces cell apoptosis by inhibiting CDK4 stability and FOXM1/ATG7-mediated autophagy.

N6-methyladenosine-modified SRPK1 promotes aerobic glycolysis of lung adenocarcinoma via PKM splicing.

BACKGROUND: The RNA N6-methyladenosine (m6A) modification has become an essential hotspot in epigenetic modulation. Serine-arginine protein kinase 1 (SRPK1) is associated with the pathogenesis of various cancers. However, the m6A modification of SRPK1 and its association with the mechanism of in lung adenocarcinoma (LUAD) remains unclear. METHODS: Western blotting and polymerase chain reaction (PCR) analyses were carried out to identify gene and protein expression. m6A epitranscriptomic microarray was utilized to the assess m6A profile. Loss and gain-of-function assays were carried out elucidate the impact of METTL3 and SRPK1 on LUAD glycolysis and tumorigenesis. RNA immunoprecipitation (RIP), m6A RNA immunoprecipitation (MeRIP), and RNA stability tests were employed to elucidate the SRPK1's METTL3-mediated m6A modification mechanism in LUAD. Metabolic quantification and co-immunoprecipitation assays were applied to investigate the molecular mechanism by which SRPK1 mediates LUAD metabolism. RESULTS: The epitranscriptomic microarray assay revealed that SRPK1 could be hypermethylated and upregulated in LUAD. The main transmethylase METTL3 was upregulated and induced the aberrant high m6A levels of SRPK1. Mechanistically, SRPK1's m6A sites were directly methylated by METTL3, which also stabilized SRPK1 in an IGF2BP2-dependent manner. Methylated SRPK1 subsequently promoted LUAD progression through enhancing glycolysis. Further metabolic quantification, co-immunoprecipitation and western blot assays revealed that SRPK1 interacts with hnRNPA1, an important modulator of PKM splicing, and thus facilitates glycolysis by upregulating PKM2 in LUAD. Nevertheless, METTL3 inhibitor STM2457 can reverse the above effects in vitro and in vivo by suppressing SRPK1 and glycolysis in LUAD. CONCLUSION: It was revealed that in LUAD, aberrantly expressed METTL3 upregulated SRPK1 levels via an m6A-IGF2BP2-dependent mechanism. METTL3-induced SRPK1 fostered LUAD cell proliferation by enhancing glycolysis, and the small-molecule inhibitor STM2457 of METTL3 could be an alternative novel therapeutic strategy for individuals with LUAD.

H3K36 methyltransferase SMYD2 affects cell proliferation and migration in Hirschsprung's disease by regulating METTL3.

The pathogenesis of Hirschsprung's disease (HSCR) is complex. Recently, it has been found that histone modifications can alter genetic susceptibility and play important roles in the proliferation, differentiation and migration of neural crest cells. H3K36 methylation plays a significant role in gene transcriptional activation and expression, but its pathogenic mechanism in HSCR has not yet been studied. This study aimed to elucidate its role and molecular mechanism in HSCR. Western blot analysis, immunohistochemistry (IHC) and reverse transcription-quantitative PCR (RT‒qPCR) were used to investigate H3K36 methylation and methyltransferase levels in dilated and stenotic colon tissue sections from children with. We confirm that SMYD2 is the primary cause of differential H3K36 methylation and influences cell proliferation and migration in HSCR. Subsequently, quantitative detection of m6A RNA methylation revealed that SMYD2 can alter m6A methylation levels. Western blot analysis, RT-qPCR, co-immunoprecipitation (co-IP), and immunofluorescence colocalization were utilized to confirm that SMYD2 can regulate METTL3 expression and affect m6A methylation, affecting cell proliferation and migration. These results confirm that the H3K36 methyltransferase SMYD2 can affect cell proliferation and migration in Hirschsprung's disease by regulating METTL3. Our study suggested that H3K36 methylation plays an important role in HSCR, confirming that the methyltransferase SMYD2 can affect m6A methylation levels and intestinal nervous system development by regulating METTL3 expression.

Resveratrol Enhances Antioxidant and Anti-Apoptotic Capacities in Chicken Primordial Germ Cells through m6A Methylation: A Preliminary Investigation.

Avian primordial germ cells (PGCs) are essential in avian transgenic research, germplasm conservation, and disease resistance breeding. However, cultured PGCs are prone to fragmentation and apoptosis, regulated at transcriptional and translational levels, with N6-methyladenosine (m6A) being the most common mRNA modification. Resveratrol (RSV) is known for its antioxidant and anti-apoptotic properties, but its effects on PGCs and the underlying mechanisms are not well understood. This study shows that RSV supplementation in cultured PGCs improves cell morphology, significantly enhances total antioxidant capacity (p < 0.01), reduces malondialdehyde levels (p < 0.05), increases anti-apoptotic BCL2 expression, and decreases Caspase-9 expression (p < 0.05). Additionally, RSV upregulates the expression of m6A reader proteins YTHDF1 and YTHDF3 (p < 0.05). m6A methylation sequencing revealed changes in mRNA m6A levels after RSV treatment, identifying 6245 methylation sites, with 1223 unique to the control group and 798 unique to the RSV group. Combined analysis of m6A peaks and mRNA expression identified 65 mRNAs with significantly altered methylation and expression levels. Sixteen candidate genes were selected, and four were randomly chosen for RT-qPCR validation, showing results consistent with the transcriptome data. Notably, FAM129A and SFRP1 are closely related to apoptosis, indicating potential research value. Overall, our study reveals the protective effects and potential mechanisms of RSV on chicken PGCs, providing new insight into its use as a supplement in reproductive stem cell culture.

Endogenous RBM4 prevents Ang II-induced cardiomyocyte hypertrophy via downregulating the expression of PTBP1.

Aberrant gene expression in cardiomyocyte has been revealed to be the fundamental essence of pathological cardiac hypertrophy. However, the detailed mechanisms are not fully understood. The underlying regulators of gene expression involved in cardiac hypertrophy remain to be further identified. Here, we report that the RNA-binding protein RNA-binding motif protein 4 (RBM4) functions as an endogenic protector that is able to fight against cardiomyocyte hypertrophy in vitro. Under pro-hypertrophic stimulation of angiotensin II (Ang II), the protein level of RBM4 in cardiomyocyte and myocardium is elevated. Knockdown of RBM4 can further aggravate cardiomyocyte hypertrophy, while over-expression of RBM4 represses cardiomyocyte hypertrophy. Mechanistically, RBM4 is localized in the nucleus and down-regulates the expression of polypyrimidine tract-binding protein 1 (PTBP1), which has been shown to aggravate cardiomyocyte hypertrophy. In addition, we suggest that the up-regulation of RBM4 in cardiomyocyte hypertrophy is caused by N6-methyladenosine (m6A). Ang II induces m6A methylation of RBM4 mRNA, which further enhances the YTH domain-containing family protein 1 (YTHDF1)-mediated translation of RBM4. Thus, our results reveal a novel pathway consisting of m6A, RBM4 and PTBP1, which is involved in cardiomyocyte hypertrophy.

Cadmium exposure elicited dynamic RNA m6A modification and epi-transcriptomic regulation in the Pacific whiteleg shrimp Litopenaeus vannamei.

N6-methyladenosine (m6A) methylation is the most prevalent post-transcriptional RNA modification in eukaryotic organisms, but its roles in the regulation of physiological resistance of marine crustaceans to heavy metal pollutants are poorly understood. In this study, the transcriptome-wide m6A RNA methylation profiles and dynamic m6A changes induced by acute Cd2+ exposure in the the pacific whiteleg shrimp Litopenaeus vannamei were comprehensively analyzed. Cd2+ toxicity caused a significant reduction in global RNA m6A methylation level, with major m6A regulators including the m6A methyltransferase METTL3 and the m6A binding protein YTHDF2 showing declined expression. Totally, 11,467 m6A methylation peaks from 6415 genes and 17,291 peaks within 7855 genes were identified from the Cd2+ exposure group and the control group, respectively. These m6A peaks were predominantly enriched in the 3' untranslated region (UTR) and around the start codon region of the transcripts. 7132 differentially expressed genes (DEGs) and 7382 differentially m6A-methylated genes (DMGs) were identified. 3186 genes showed significant changes in both gene expression and m6A methylation levels upon cadmium exposure, and they were related to a variety of biological processes and gene pathways. Notably, an array of genes associated with antioxidation homeostasis, transmembrane transporter activity and intracellular detoxification processes were significantly enriched, demonstrating that m6A modification may mediate the physiological responses of shrimp to cadmium toxicity via regulating ROS balance, Cd2+ transport and toxicity mitigation. The study would contribute to a deeper understanding of the evolutionary and functional significance of m6A methylation to the physiological resilience of decapod crustaceans to heavy metal toxicants.