N6-Methyladenosine Reader YTHDF3-Mediated CEBPA Translation Maintains Genomic Stability and Stem Cells Function to Prevent Liver Injury and Hepatocellular Carcinoma [scRNA-seq]
Ontology highlight
ABSTRACT: BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) induced by chronic liver damage is a major cause of cancer mortality, but its precise epigenetic mechanisms are severely under studied. In addition, the role of N6-methyladenine (m6A) reader YTHDF3 in human diseases remains poorly understood. METHODS: Liver injury and hepatocarcinogenesis in mice were induced by chemical. CRISPR/Cas9 technology was used to construct Ythdf3 and Mettl14 knockout mice. Hepatic cell population characteristics was determined by means of 10X single-cell RNA-seq and flow cytometry. Cell proliferation and DNA damage were evaluated by immunofluorescence, immunohistochemistry, and western blot. Liver organoids were cultured to examine liver stem cells function. MeRIP-seq was used to reveal alterations in m6A methylation patterns impacted by chemical-induced liver injury. RIP-seq and Ribo-seq were applied to identify YTHDF3 targets and determine translation efficiency. Small interfering RNAs and dCas13b-FTO-sgRNA plasmids were used to evaluate the function of YTHDF3 and CEBPA in vitro. RESULTS: YTHDF3 depletion exacerbated chemical-induced liver injury with a reduction in functional hepatocytes and stem cells. Furthermore, METTL14 and YTHDF3-dependent RNA m6A dysregulation induced DNA damage and promoted development of HCC. Mechanistically, knockout of Ythdf3 impeded the translation of CCAAT/enhancer-binding protein-alpha (CEBPA), subsequently inhibited expression of PARP1 and PRDX2 to promote DNA damage and induce genomic instability, finally leading to liver injury and HCC. CONCLUSIONS: m6A/YTHDF3/CEBPA regulatory axis plays an essential role in governing cell fates and genomic stability, thereby preventing liver injury and HCC, and offers potential therapeutic avenue for targeting YTHDF3 and CEBPA in the treatment of HCC.
Project description:BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) induced by chronic liver damage is a major cause of cancer mortality, but its precise epigenetic mechanisms are severely under studied. In addition, the role of N6-methyladenine (m6A) reader YTHDF3 in human diseases remains poorly understood. METHODS: Liver injury and hepatocarcinogenesis in mice were induced by chemical. CRISPR/Cas9 technology was used to construct Ythdf3 and Mettl14 knockout mice. Hepatic cell population characteristics was determined by means of 10X single-cell RNA-seq and flow cytometry. Cell proliferation and DNA damage were evaluated by immunofluorescence, immunohistochemistry, and western blot. Liver organoids were cultured to examine liver stem cells function. MeRIP-seq was used to reveal alterations in m6A methylation patterns impacted by chemical-induced liver injury. RIP-seq and Ribo-seq were applied to identify YTHDF3 targets and determine translation efficiency. Small interfering RNAs and dCas13b-FTO-sgRNA plasmids were used to evaluate the function of YTHDF3 and CEBPA in vitro. RESULTS: YTHDF3 depletion exacerbated chemical-induced liver injury with a reduction in functional hepatocytes and stem cells. Furthermore, METTL14 and YTHDF3-dependent RNA m6A dysregulation induced DNA damage and promoted development of HCC. Mechanistically, knockout of Ythdf3 impeded the translation of CCAAT/enhancer-binding protein-alpha (CEBPA), subsequently inhibited expression of PARP1 and PRDX2 to promote DNA damage and induce genomic instability, finally leading to liver injury and HCC. CONCLUSIONS: m6A/YTHDF3/CEBPA regulatory axis plays an essential role in governing cell fates and genomic stability, thereby preventing liver injury and HCC, and offers potential therapeutic avenue for targeting YTHDF3 and CEBPA in the treatment of HCC.
Project description:BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) induced by chronic liver damage is a major cause of cancer mortality, but its precise epigenetic mechanisms are severely under studied. In addition, the role of N6-methyladenine (m6A) reader YTHDF3 in human diseases remains poorly understood. METHODS: Liver injury and hepatocarcinogenesis in mice were induced by chemical. CRISPR/Cas9 technology was used to construct Ythdf3 and Mettl14 knockout mice. Hepatic cell population characteristics was determined by means of 10X single-cell RNA-seq and flow cytometry. Cell proliferation and DNA damage were evaluated by immunofluorescence, immunohistochemistry, and western blot. Liver organoids were cultured to examine liver stem cells function. MeRIP-seq was used to reveal alterations in m6A methylation patterns impacted by chemical-induced liver injury. RIP-seq and Ribo-seq were applied to identify YTHDF3 targets and determine translation efficiency. Small interfering RNAs and dCas13b-FTO-sgRNA plasmids were used to evaluate the function of YTHDF3 and CEBPA in vitro. RESULTS: YTHDF3 depletion exacerbated chemical-induced liver injury with a reduction in functional hepatocytes and stem cells. Furthermore, METTL14 and YTHDF3-dependent RNA m6A dysregulation induced DNA damage and promoted development of HCC. Mechanistically, knockout of Ythdf3 impeded the translation of CCAAT/enhancer-binding protein-alpha (CEBPA), subsequently inhibited expression of PARP1 and PRDX2 to promote DNA damage and induce genomic instability, finally leading to liver injury and HCC. CONCLUSIONS: m6A/YTHDF3/CEBPA regulatory axis plays an essential role in governing cell fates and genomic stability, thereby preventing liver injury and HCC, and offers potential therapeutic avenue for targeting YTHDF3 and CEBPA in the treatment of HCC.
Project description:BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) induced by chronic liver damage is a major cause of cancer mortality, but its precise epigenetic mechanisms are severely under studied. In addition, the role of N6-methyladenine (m6A) reader YTHDF3 in human diseases remains poorly understood. METHODS: Liver injury and hepatocarcinogenesis in mice were induced by chemical. CRISPR/Cas9 technology was used to construct Ythdf3 and Mettl14 knockout mice. Hepatic cell population characteristics was determined by means of 10X single-cell RNA-seq and flow cytometry. Cell proliferation and DNA damage were evaluated by immunofluorescence, immunohistochemistry, and western blot. Liver organoids were cultured to examine liver stem cells function. MeRIP-seq was used to reveal alterations in m6A methylation patterns impacted by chemical-induced liver injury. RIP-seq and Ribo-seq were applied to identify YTHDF3 targets and determine translation efficiency. Small interfering RNAs and dCas13b-FTO-sgRNA plasmids were used to evaluate the function of YTHDF3 and CEBPA in vitro. RESULTS: YTHDF3 depletion exacerbated chemical-induced liver injury with a reduction in functional hepatocytes and stem cells. Furthermore, METTL14 and YTHDF3-dependent RNA m6A dysregulation induced DNA damage and promoted development of HCC. Mechanistically, knockout of Ythdf3 impeded the translation of CCAAT/enhancer-binding protein-alpha (CEBPA), subsequently inhibited expression of PARP1 and PRDX2 to promote DNA damage and induce genomic instability, finally leading to liver injury and HCC. CONCLUSIONS: m6A/YTHDF3/CEBPA regulatory axis plays an essential role in governing cell fates and genomic stability, thereby preventing liver injury and HCC, and offers potential therapeutic avenue for targeting YTHDF3 and CEBPA in the treatment of HCC.
Project description:Accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) lumen triggers unfolded protein response (UPR) for stress adaptation, the failure of which induces cell apoptosis and tissue/organ damage. The molecular switches underlying how the UPR selects for stress adaptation over apoptosis remain unknown. Here we discovered that accumulation of unfolded/misfolded proteins selectively induces N6-adenosine-methyltransferase-14 (METTL14) expression. METTL14 promotes CHOP mRNA decay through its 3’UTR N6-adenosine methylation (m6A) to inhibit its downstream pro-apoptotic target genes expression. UPR induces METTL14 expression through competing the HRD1-ERAD machinery to block METTL14 ubiquitination and degradation. Therefore, mice with liver-specific METTL14 deletion are highly susceptible to both acute pharmacological and alpha-1 antitrypsin (AAT) deficiency-induced ER proteotoxic stress and liver injury. Further hepatic CHOP deletion protects METTL14 knockout mice from ER stress-induced liver damage. Our study reveals a crosstalk between ER stress and mRNA m6A pathways, the ERm6A pathway, for ER stress adaptation to proteotoxicity.
Project description:Single nucleotide polymorphisms in the FTO gene encoding a m6A demthylase are associated with obesity and cancer development. However, the functional role of FTO in the developemnt of progression of hepatocellular carcinoma (HCC) as a proteotypic obesity-associated cancer remains unclear. Here, we have generated mice with hepatic FTO deficiency (FTOL-KO) and subjected them to DEN induced HCC-development. FTOL-KO mice exhibit increased HCC burden. While control mice exhibit a dynamic regulation of FTO upon induction of liver damage, this response is abrogated in mice lacking FTO. Proteomic analyses revealed that liver damage-induced increases in FTO expression promotes m6A-demethylation of CUL4A reducing its protein expression. Functionally, knockdown of CUL4A restores the increased hepatocyte proliferation observed upon loss of FTO. Collectively, our study reveals a protective role for FTO-dependent dynamic m6A mRNA demethylation of CUL4A in the initiation of HCC development.
Project description:Oxaliplatin as a first-line drug frequently causes the chemo-resistance on colorectal cancer (CRC). N6-methyladenosine (m6A) methylation has been largely acknowledged in multiple biological functions. However, the molecular mechanisms underlying the m6A methylation in modulating anticancer drug resistance in CRC are still obscure. In present study, RIP-seq was conducted to investigate the occupancy of N6-methyladenosine RNA binding protein 3 (YTHDF3) served as “readers” that can recognize m6A modification site in HCT116 cells with oxaliplatin resistance (HCT116R). Then, YTHDF3 was knockdown by siRNA in HCT116 cells with oxaliplatin resistance, and RIP-seq was further conducted to investigate m6A methylation of HCT116, HCT116R and HCT116R cells with YTHDF3 knockdown.
Project description:We show that N6-methyladenosine (m6A), the most abundant internal modification in mRNA/lncRNA with still poorly characterized function, alters RNA structure to facilitate the access of RBM for heterogeneous nuclear ribonucleoprotein C (hnRNP C). We term this mechanism m6A-switch. Through combining PAR-CLIP with Me-RIP, we identify 39,060 m6A-switches among hnRNP C binding sites transcriptome-wide. We show that m6A-methyltransferases METTL3 or METTL14 knockdown decreases hnRNP C binding at 16,582 m6A-switches. Taken together, 2,798 m6A-switches of high confidence are identified to mediate RNA-hnRNP C interactions and affect diverse biological processes including cell cycle regulation. These findings reveal the biological importance of m6A and provide insights into the sophisticated regulation of RNA-RBP interactions through m6A-induced RNA structural remodeling. Measure the m6A methylated hnRNP C binding sites transcriptome-wide by PARCLIP-MeRIP; measure the differential hnRNP C occupancies upon METTL3/METTL14 knockdown by PAR-CLIP; measure RNA abundance and splicing level changes upon HNRNPC, METTL3 and METTL14 knockdown
Project description:Knocking down YTHDF3 in breast cancer cells resulted in an altered gene expression profile N6-methyl-adenosine (m6A) is the most prevalent internal chemical modification in eukaryotic messenger RNAs and emerging as a critical mRNA chemical mark that mediates post-transcriptional gene expression regulation. YTHDF3 facilitates translation and decay of m6A-modified mRNAs. However, the role for YTHDF3 protein in breast cancer brain metastasis remain to be elucidated. We found that YTHDF3 is overexpressed in brain metastasis of breast cancer cells. Our study will characterize the expression profiling in YTHDF3 silencing breast cancer cells compared to shControl breast cancers cells. The objectives are to identify expression profiles that are specific to shYTHDF3 breast cancer cell to identify new the signaling pathway of YTHDF3 for brain metastasis of breast cancer cells.
Project description:Knocking down YTHDF3 in breast cancer cells resulted in an altered gene expression profile N6-methyl-adenosine (m6A) is the most prevalent internal chemical modification in eukaryotic messenger RNAs and emerging as a critical mRNA chemical mark that mediates post-transcriptional gene expression regulation. YTHDF3 facilitates translation and decay of m6A-modified mRNAs. However, the role for YTHDF3 protein in breast cancer brain metastasis remain to be elucidated. We found that YTHDF3 is overexpressed in brain metastasis of breast cancer cells. Our study will characterize the expression profiling in YTHDF3 silencing breast cancer cells compared to shControl breast cancers cells. The objectives are to identify expression profiles that are specific to shYTHDF3 breast cancer cell to identify new the signaling pathway of YTHDF3 for brain metastasis of breast cancer cells.
Project description:Chemical modification of RNAs is important for post-transcriptional gene regulation. The METTL3-METTL14 complex generates most N6-methyladenosine (m6A) modifications in mRNAs, and dysregulated methyltransferase expression has been linked to numerous cancers. Here we show that m6A modification location, rather than the overall modification level, can impact oncogenesis. A gain-of-function missense mutation found in cancer patients, METTL14R298P, promotes malignant cell growth in culture and in transgenic mice. The mutant methyltransferase preferentially modifies noncanonical sites and transforms gene expression without increasing global m6A levels in mRNAs. The altered substrate specificity is intrinsic to METTL3-METTL14, helping us to propose a structural model for how the METTL3-METTL14 complex detects RNA sequences. Together, our work highlights that m6A location is important for function and that noncanonical methylation sites may impact aberrant gene expression and oncogenesis.