The m6A methyltransferase METTL3 regulates muscle maintenance and growth in mice.
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ABSTRACT:
SUBMITTER: Petrosino JM
PROVIDER: S-EPMC8748755 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Recent studies have identified that N6-methyladenosine (m6A) extensively participates in the myocardial injury pathophysiological process. However, the role of m6A on sepsis-induced myocardial injury is still unclear. Here, we investigated the functions and mechanism of m6A methyltransferase METTL3 for septic myocardial injury. Results illustrated that the m6A modification level and METTL3 up-regulated in the lipopolysaccharide (LPS)-induced cardiomyocytes (H9C2 cells). Methylated RNA immunoprecipitation sequencing (MeRIP-Seq) revealed the m6A profile of the septic myocardial injury cellular model. Functionally, METTL3 knockdown repressed the inflammatory damage of cardiomyocytes induced by LPS. Mechanistically, we found that HDAC4 had remarkable m6A modification sites on its 3'-UTR genome, acting as the downstream target of METTL3. Besides, m6A reader IGF2BP1 recognized the m6A modification sites on HDAC4 mRNA and enhanced its RNA stability. In conclusion, the findings illustrated a role of METTL3/IGF2BP1/m6A/HDAC4 axis on sepsis-induced myocardial injury, which might provide novel therapeutic strategy for septic myocardial injury.
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Project description:Nonalcoholic steatohepatitis (NASH) is a key step in the progression of nonalcoholic fatty liver (NAFL) to cirrhosis. However, the molecular mechanisms of the NAFL-to-NASH transition are largely unknown. Here, we identify methyltransferase like 3 (METTL3) as a key negative regulator of NASH pathogenesis. Hepatocyte-specific deletion of Mettl3 drives NAFL-to-NASH progression by increasing CD36-mediated hepatic free fatty acid uptake and CCL2-induced inflammation, which is due to increased chromatin accessibility in the promoter region of Cd36 and Ccl2. Antibody blockade of CD36 and CCL2 ameliorates NASH progression in hepatic Mettl3 knockout mice. Hepatic overexpression of Mettl3 protects against NASH progression by inhibiting the expression of CD36 and CCL2. Mechanistically, METTL3 directly binds to the promoters of the Cd36 and Ccl2 genes and recruits HDAC1/2 to induce deacetylation of H3K9 and H3K27 in their promoters, thus suppressing Cd36 and Ccl2 transcription. Furthermore, METTL3 is translocated from the nucleus to the cytosol in NASH, which is associated with CDK9-mediated phosphorylation of METTL3. Our data reveal a mechanism by which METTL3 negatively regulates hepatic Cd36 and Ccl2 gene transcription via a histone modification pathway for protection against NASH progression.
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Project description:Prostate cancer (PCa) is a leading cause of cancer-related deaths and is driven by aberrant androgen receptor (AR) signalling. For this reason, androgen deprivation therapies (ADTs) that suppress androgen-induced PCa progression either by preventing androgen biosynthesis or via AR signalling inhibition (ARSi) are common treatments. The N6-methyladenosine (m6A) RNA modification is involved in regulating mRNA expression, translation, and alternative splicing, and through these mechanisms has been implicated in cancer development and progression. RNA-m6A is dynamically regulated by the METTL3 RNA methyltransferase complex and the FTO and ALKBH5 demethylases. While there is evidence supporting a role for aberrant METTL3 in many cancer types, including localised PCa, the wider contribution of METTL3, and by inference m6A, in androgen signalling in PCa remains poorly understood. Therefore, the aim of this study was to investigate the expression of METTL3 in PCa patients and study the clinical and functional relevance of METTL3 in PCa. It was found that METTL3 is aberrantly expressed in PCa patient samples and that siRNA-mediated METTL3 knockdown or METTL3-pharmacological inhibition significantly alters the basal and androgen-regulated transcriptome in PCa, which supports targeting m6A as a novel approach to modulate androgen signalling in PCa.
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Project description:Muscle-specific adult stem cells (MuSCs) are required for skeletal muscle regeneration. To ensure efficient skeletal muscle regeneration after injury, MuSCs must undergo state transitions as they are activated from quiescence, give rise to a population of proliferating myoblasts, and continue either to terminal differentiation, to repair or replace damaged myofibers, or self-renewal to repopulate the quiescent population. Changes in MuSC/myoblast state are accompanied by dramatic shifts in their transcriptional profile. Previous reports in other adult stem cell systems have identified alterations in the most abundant internal mRNA modification, N6-methyladenosine (m6A), conferred by its active writer, METTL3, to regulate cell state transitions through alterations in the transcriptional profile of these cells. Our objective was to determine if m6A-modification deposition via METTL3 is a regulator of MuSC/myoblast state transitions in vitro and in vivo. Using liquid chromatography/mass spectrometry we identified that global m6A levels increase during the early stages of skeletal muscle regeneration, in vivo, and decline when C2C12 myoblasts transition from proliferation to differentiation, in vitro. Using m6A-specific RNA-sequencing (MeRIP-seq), a distinct profile of m6A-modification was identified, distinguishing proliferating from differentiating C2C12 myoblasts. RNAi studies show that reducing levels of METTL3, the active m6A methyltransferase, reduced global m6A levels and forced C2C12 myoblasts to prematurely differentiate. Reducing levels of METTL3 in primary mouse MuSCs prior to transplantation enhanced their engraftment capacity upon primary transplantation, however their capacity for serial transplantation was lost. In conclusion, METTL3 regulates m6A levels in MuSCs/myoblasts and controls the transition of MuSCs/myoblasts to different cell states. Furthermore, the first transcriptome wide map of m6A-modifications in proliferating and differentiating C2C12 myoblasts is provided and reveals a number of genes that may regulate MuSC/myoblast state transitions which had not been previously identified.
| S-EPMC7524727 | biostudies-literature
Project description:Methylation of adenine N6 (m6A) is the most frequent RNA modification. On mRNA, it is catalyzed by the METTL3-14 heterodimer complex, which plays a key role in acute myeloid leukemia (AML) and other types of blood cancers and solid tumors. Here, we disclose the first proteolysis targeting chimeras (PROTACs) for an epitranscriptomics protein. For designing the PROTACs, we made use of the crystal structure of the complex of METTL3-14 with a potent and selective small-molecule inhibitor (called UZH2). The optimization of the linker started from a desfluoro precursor of UZH2 whose synthesis is more efficient than that of UZH2. The first nine PROTAC molecules featured PEG- or alkyl-based linkers, but only the latter showed cell penetration. With this information in hand, we synthesized 26 PROTACs based on UZH2 and alkyl linkers of different lengths and rigidity. The formation of the ternary complex was validated by a FRET-based biochemical assay and an in vitro ubiquitination assay. The PROTACs 14, 20, 22, 24, and 30, featuring different linker types and lengths, showed 50% or higher degradation of METTL3 and/or METTL14 measured by Western blot in MOLM-13 cells. They also showed substantial degradation on three other AML cell lines and prostate cancer cell line PC3.
| S-EPMC10900215 | biostudies-literature
Project description:N6-methyladenosine (m6A), a ubiquitous RNA modification, is installed by METTL3-METTL14 complex. The structure of the heterodimeric complex between the methyltransferase domains (MTDs) of METTL3 and METTL14 has been previously determined. However, the MTDs alone possess no enzymatic activity. Here we present the solution structure for the zinc finger domain (ZFD) of METTL3, the inclusion of which fulfills the methyltransferase activity of METTL3-METTL14. We show that the ZFD specifically binds to an RNA containing 5'-GGACU-3' consensus sequence, but does not to one without. The ZFD thus serves as the target recognition domain, a structural feature previously shown for DNA methyltransferases, and cooperates with the MTDs of METTL3-METTL14 for catalysis. However, the interaction between the ZFD and the specific RNA is extremely weak, with the binding affinity at several hundred micromolar under physiological conditions. The ZFD contains two CCCH-type zinc fingers connected by an anti-parallel β-sheet. Mutational analysis and NMR titrations have mapped the functional interface to a contiguous surface. As a division of labor, the RNA-binding interface comprises basic residues from zinc finger 1 and hydrophobic residues from β-sheet and zinc finger 2. Further we show that the linker between the ZFD and MTD of METTL3 is flexible but partially folded, which may permit the cooperation between the two domains during catalysis. Together, the structural characterization of METTL3 ZFD paves the way to elucidate the atomic details of the entire process of RNA m6A modification.
| S-EPMC6418081 | biostudies-literature
Project description:Recent studies have indicated that long noncoding RNA (lncRNA) and N6-methyladenosine (m6A) methylation modification play critical roles in human cancers; however, their regulation on cervical cancer is largely unclear. Here, our study tries to investigate the underlying mechanisms by which lncRNA FOXD2 adjacent opposite strand RNA 1 (FOXD2-AS1) modulates cervical cancer tumorigenesis. Results illuminated that FOXD2-AS1 expression was significantly upregulated in cervical cancer cells and tissue, which was closely correlated to the unfavorable prognosis. Functionally, gain and loss-of-function assays showed that FOXD2-AS1 promoted the migration and proliferation of cervical cancer cells. Besides, FOXD2-AS1 silencing repressed the tumor growth in vivo. Mechanistically, m6A methyltransferase methyltransferase-like 3 (METTL3) enhanced the stability of FOXD2-AS1 and maintained its expression. Moreover, FOXD2-AS1 recruited lysine-specific demethylase 1 (LSD1) to the promoter region of p21 to silence its transcription abundance. In conclusion, these findings support that METTL3/FOXD2-AS1 accelerates cervical cancer progression via a m6A-dependent modality, which may serve as a potential therapeutic target for cervical cancer.
| S-EPMC8450180 | biostudies-literature
Project description:Purpose: Although many biological processes are involved in the modification of N6-methyladenosine (m6A), the exact role of m6A in the development of malignant tumors remains unclear. Methyltransferase 3 (METTL3) is a major RNA N6-methyladenosine methyltransferase. We aimed to explore the role of METTL3 in colorectal cancer (CRC) carcinogenesis and disease progression. Methods: In this study, immunohistochemistry was performed with a tissue microarray. qRT-PCR and Western blots were used to evaluate the expression of METTL3 in CRC cells. The effect of METTL3 on cell proliferation, migration and invasion of CRC cells was examined by IncuCyte Live Cell Analysis System and transwell assay, respectively. Results: The results suggested that positive expression of METTL3 was significantly associated with longer survival time (P=0.011). We next demonstrated that overexpression of METTL3 could inhibit proliferation, migration and invasion in CRC cells, while downregulation of METTL3 shows the opposite result. Furthermore, downregulation of METTL3 resulted in activation of p-p38 and p-ERK. Moreover, the inhibitors of p38 or ERK kinase could significantly reverse the effect of migration and invasion, which was induced by knockdown of METTL3. Conclusion: We concluded that METTL3 played a tumor-suppressive role in CRC cell proliferation, migration and invasion through p38/ERK pathways, which indicated that METTL3 might be a novel marker for CRC carcinogenesis, progression and survival.
| S-EPMC6556107 | biostudies-literature
Project description:Activation of hepatic stellate cells (HSCs) is a central driver of liver fibrosis. Previous investigations have identified various altered epigenetic landscapes during the cellular progression of HSC activation. N6-methyladenosine (m6A) is the most abundant internal RNA modification in eukaryotic cells and is dynamically regulated under various physiological and pathophysiological conditions. However, the functional role of Mettl3-mediated m6A in liver fibrosis remains elusive. Here, we found that the HSC-specific knockout of m6A methyltransferase Mettl3 suppressed HSC activation and significantly alleviated liver fibrosis. Multi-omics analysis of HSCs showed that Mettl3 depletion reduced m6A deposition on mRNA transcripts of Lats2 (a central player of the Hippo/YAP signaling pathway) and slowed down their degradation. Elevated Lats2 increased phosphorylation of the downstream transcription factor YAP, suppressed YAP nuclear translocation, and decreased pro-fibrotic gene expression. Overexpressing YAP mutant resistant to phosphorylation by Lats2 partially rescued the activation and pro-fibrotic gene expression of Mettl3-deficient HSCs. Our study revealed that disruption of Mettl3 in HSCs mitigated liver fibrosis by controlling the Hippo/YAP signaling pathway, providing potential therapeutic strategies to alleviate liver fibrosis by targeting epitranscriptomic machinery.
| S-EPMC9734030 | biostudies-literature
Project description:In many members of the animal kingdom, and in particular mammals, skeletal muscle evolved to serve fundamental roles in their health and architectural integrity. While it is clear that dynamic fluctuations of specific gene expression is important for normal muscle function, it is also crucial in the response of skeletal muscle to insults, yet little is known on how such fluctuations are regulated at the post-transcriptional level to impact muscle proteome. Here we report the first genome-wide analysis of mRNA methyladenosine (m6A) dynamics underlying skeletal muscle hypertrophic growth following overload-induced stress. We show that METTL3, the enzyme responsible for m6A formation, orchestrate a previously unrecognized post-transcriptional mechanism controlling skeletal muscle size and function. We found that METTL3 and concomitantly m6A are increased during hypertrophy; manipulating this increase through exogenous delivery of METTL3 is sufficient to induce skeletal muscle growth even in the absence of external triggers. Myofiber-specific conditional genetic deletion of METTL3 abrogated the ability of muscle to undergo overload-induced hypertrophy and led to a spontaneous muscle wasting phenotype over time. In turn, isolation of muscle-specific ribosome-associated transcripts showed that METTL3 affects the translation of specific m6A-modified mRNAs participating in the activin/myostatin pathway, which includes key regulators of muscle size. METTL3 is essential to repress the translation of activin type 2A receptors (ACVR2A), consequently blunting downstream activation of anti-hypertrophic signaling. Notably, the observed hypertrophic growth defect of METTL3-deficient mice can be overcome with co-administration of a myostatin inhibitor. Our findings identify a novel post-transcriptional mechanism of regulating the activin receptor pathway and demonstrate that the N6-adenosine methyltransferase METTL3 is required for and promotes the hypertrophic response of skeletal muscle.
2021-12-10 | GSE179368 | GEO