Project description:Liver-specific deficiency of Mettl3 causes liver injury. By performing RNA sequencing (RNA-seq) analysis on the Mettl3-deficient versus control livers, we identified the potential target genes that were closely associated with the liver phenotype in liver-specific Mettl3 knockout mice. RNA-seq analysis revealed extensive metabolic reprogramming in Mettl3-deficient livers. These results demonstrated that Mettl3 coordinates metabolic homeostasis and functional maturation during postnatal liver development.
Project description:The N6-methyladenosine (m6A) mRNA modification and the mitochondrial respiratory chain (MRC) hold paramount importance in the advancement of MASLD. This study thoroughly investigates the relationship and impact of m6A mRNA modification and mitochondrial function in the progression of MASLD. Here we report that the mRNA and protein levels of mitochondrial respiratory chain (MRC) subunits showed inconsistent trends in vivo experiments. Abnormal m6A modification and mitochondrial dysfunction in MASLD were attributed to the upregulation of methyltransferase like 3 (Mettl3) and the downregulation of YTH N6-methyladenosine RNA binding protein 1 (YTHDF1) induced by high-fat foods. Mettl3 promoted the MRC's function. However, knockout of the reader protein YTHDF1, which plays a crucial role in the m6A modification process, counteracted the effect of Mettl3 and suppressed MRC. In MASLD, damage to the MRC may be regulated by the Mettl3-m6A-YTHDF1 complex axis, especially by the role of YTHDF1. Our research has offered a novel perspective on the involvement of m6A mRNA methylation in the pathogenesis of MASLD.
Project description:N6-methyladenosine (m6A) RNA methylation is the most abundant modification on mRNAs and plays important roles in various biological processes. The formation of m6A is catalyzed by a methyltransferase complex including methyltransferase like 3 (METTL3) as a key factor. However, the in vivo functions of METTL3 and m6A modification in mammalian development remain unclear. Here we show that specific inactivation of Mettl3 in mouse nervous system causes severe developmental defects in the brain. Mettl3 conditional knockout mice manifest cerebellar hypoplasia caused by drastically enhanced apoptosis of new born cerebellar granule cells (CGCs) in the external granular layer (EGL). METTL3 depletion induced loss of m6A modification causes extended RNA half-lives and aberrant splicing events, consequently leading to dysregulation of transcriptome-wide gene expression and premature CGC death. Our findings reveal a critical role of METTL3-mediated m6A in regulating the development of mammalian cerebellum.
Project description:To investigate the role of METTL3-mediated m6A modification, we performed m6A-sequencing to map the m6A modification in control or METTL3 knockdown BGC823 cells.
Project description:Here we determine the map of RNA methylation (m6A) in mouse embrionic stem cells, and Mettl3 knock out cells Examination of m6A modification sites on the transcriptome of mouse Embryonic stem cells and Embryonic Mettl3 knock out cells, using a m6A specific antibody.
Project description:Esophageal cancer is a lethal malignancy with high mortality rate, while the molecular mechanisms underlying esophageal cancer pathogenesis are stillis poorly understood. Here we found that the N6-methyladenosine (m6A) methyltransferase METTL3 is significantly up-regulated in esophageal squamous cell carcinoma (ESCC) and associated with poor patient prognosis. Depletion of METTL3 results in decreased ESCC growth and progression in vitro and in vivo. We further established ESCC initiation and progression models using Mettl3 conditional knockout mouse and revealed that Mettl3 mediated m6A modification is essential for promotes ESCC initiation and progression in vivo. Moreover, using METTL3 overexpression ESCC cell model and Mettl3 conditional knockin mouse model, we demonstrated the critical function of Mettl3 in promoting in vivo ESCC tumorigenesis in vitro and in vivo. Mechanistically, Mettl3 catalyzed m6A modification promotes NOTCH1 expression and the activation of Notch signaling pathway. Forced activation of Notch signaling pathway successfully rescues the growth, migration and invasion capacities of METTL3 depleted ESCC cells. Our data uncovered important mechanistical insights underlying ESCC tumorigenesis and provided molecular basis for the development of novel strategies for ESCC diagnosis and treatment.
Project description:To investigate the role of METTL3-mediated m6A modification in liver, we performed m6A-sequencing to map the m6A modification in liver tissues of wild type (WT) and liver-sepcific Mettl3-KO mice.
Project description:Background: N6-methyladenosine (m6A) RNA modification plays a crucial role in various biological events and is implicated in various metabolic-related diseases. However, its role in MASLD remains unclear. This study aims to investigate the impact of Mettl3 on MASLD through multi-omics analysis, with a focus on exploring its potential mechanisms of action. Methods: MASLD mouse models were established by feeding a high-fat diet for 12 weeks, and Mettl3 stable overexpression AML12 cell models were constructed via lentiviral transfection. Subsequent transcriptomic and proteomic analyses, as well as integrated analysis between different omics datasets, were conducted. Results: Mettl3 expression significantly increased in MASLD mouse models. In the transcriptomic and proteomic analyses, we identified 848 genes with significant inconsistencies between transcriptomic and proteomic datasets. GO/KEGG enrichment terms may involve post-transcriptional modifications, particularly Mettl3-mediated m6A modification. Subsequently, through integrated proteomic analysis of Mettl3-overexpressed AML12 cell models and MASLD mouse models, we selected the top 20 co-upregulated and co-downregulated GO/KEGG terms as the main biological processes influenced by Mettl3 in MASLD. By intersecting with pathways obtained from previous integrated analyses, we identified GO/KEGG terms affected by Mettl3-induced m6A modification. Protein-protein interaction analysis of proteins involved in these pathways highlighted GAPDH, ENO1, and TPI1 as three key hub genes. Conclusion: In MASLD, Mettl3 regulates the glycolytic pathway through m6A modification, influencing the occurrence and development of the disease via the key hub genes GAPDH, ENO1, and TPI1. These findings expand our understanding of MASLD and provide strong evidence for potential therapeutic targets and drug development.