BACKGROUND Increasing evidence has demonstrated that N6-methyladenosine(m6A)RNA modification plays an essential role in a wide range of pathological conditions.Impaired autophagy is a critical hallmark of acute pancre...BACKGROUND Increasing evidence has demonstrated that N6-methyladenosine(m6A)RNA modification plays an essential role in a wide range of pathological conditions.Impaired autophagy is a critical hallmark of acute pancreatitis(AP).AIM To explore the role of the m6A modification of ZKSCAN3 in the regulation of autophagy in AP.METHODS The AP mouse cell model was established by cerulein-treated mouse pancreatic acinar cells(MPC-83),and the results were confirmed by the levels of amylase and inflammatory factors.Autophagy activity was evaluated by specific identification of the autophagy-related microstructure and the expression of autophagy-related genes.ZKSCAN3 and ALKBH5 were knocked down to study the function in AP.A m6A RNA binding protein immunoprecipitation assay was used to study how the m6A modification of ZKSCAN3 mRNA is regulated by ALKBH.RESULTS The increased expression of amylase and inflammatory factors in the supernatant and the accumulation of autophagic vacuoles verified that the AP mouse cell model was established.The downregulation of LAMP2 and upregulation of LC3-II/I and SQSTM1 demonstrated that autophagy was impaired in AP.The expression of ZKSCAN3 was upregulated in AP.Inhibition of ZKSCAN3 increased the expression of LAMP2 and decreased the expression of the inflammatory factors,LC3-II/I and SQSTM1.Furthermore,ALKBH5 was upregulated in AP.Knockdown of ALKBH5 downregulated ZKSCAN3 expression and restored decreased autophagic flux in AP.Notably,the bioinformatic analysis revealed 23 potential m6A modification sites on ZKSCAN3 mRNA.The m6A modification of ZKSCAN3 mRNA was significantly decreased in AP.Knockdown of ALKBH5 increased the modification of ZKSCAN3 mRNA,which confirmed that ALKBH5 upregulated ZKSCAN3 expression in a m6A-dependent manner.CONCLUSION ALKBH5 inhibits autophagic flux through m6A demethylation of ZKSCAN3 mRNA in AP,thereby aggravating the severity of the disease.展开更多
N6-methyladenosine(m6A)is a reversible epigenetic modification, which is one of the most abundant modifiers in eukaryotic cells and has been commonly reported in messenger RNAs and non-coding RNAs. The processing modi...N6-methyladenosine(m6A)is a reversible epigenetic modification, which is one of the most abundant modifiers in eukaryotic cells and has been commonly reported in messenger RNAs and non-coding RNAs. The processing modification of m6A regulates RNA transcription, processing, splicing, degradation, and translation, and plays an important role in the biological process of tumors. Circular RNA, which lacks the 5' cap structure, has been mistakenly regarded as a "junk sequence" generated by accidental shearing during the transcription process. However, it has been found that circRNAs can be involved in tumor invasion and metastasis through microRNAs, binding proteins, translated peptides, and m6A modifications. In this paper, we reviewed the role of m6A modifications in circRNA regulation and their functions in hepatocellular carcinoma and discussed their potential clinical applications and future development in this field.展开更多
BACKGROUND N6-methyladenosine(m6A)methylation modification exists in Epstein-Barr virus(EBV)primary infection,latency,and lytic reactivation.It also modifies EBV latent genes and lytic genes.EBV-associated gastric can...BACKGROUND N6-methyladenosine(m6A)methylation modification exists in Epstein-Barr virus(EBV)primary infection,latency,and lytic reactivation.It also modifies EBV latent genes and lytic genes.EBV-associated gastric cancer(EBVaGC)is a distinctive molecular subtype of GC.We hypothesized EBV and m6A methylation regulators interact with each other in EBVaGC to differentiate it from other types of GC.AIM To investigate the mechanisms of m6A methylation regulators in EBVaGC to determine the differentiating factors from other types of GC.METHODS First,The Cancer Gene Atlas and Gene Expression Omnibus databases were used to analyze the expression pattern of m6A methylation regulators between EBVaGC and EBV-negative GC(EBVnGC).Second,we identified Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)functional enrichment of m6A-related differentially expressed genes.We quantified the relative abundance of immune cells and inflammatory factors in the tumor microenvironment(TME).Finally,cell counting kit-8 cell proliferation test,transwell test,and flow cytometry were used to verify the effect of insulin-like growth factor binding protein 1(IGFBP1)in EBVaGC cell lines.RESULTS m6A methylation regulators were involved in the occurrence and development of EBVaGC.Compared with EBVnGC,the expression levels of m6A methylation regulators Wilms tumor 1-associated protein,RNA binding motif protein 15B,CBL proto-oncogene like 1,leucine rich pentatricopeptide repeat containing,heterogeneous nuclear ribonucleoprotein A2B1,IGFBP1,and insulin-like growth factor 2 binding protein 1 were significantly downregulated in EBVaGC(P<0.05).The overall survival rate of EBVaGC patients with a lower expression level of IGFBP1 was significantly higher(P=0.046).GO and KEGG functional enrichment analyses showed that the immunity pathways were significantly activated and rich in immune cell infiltration in EBVaGC.Compared with EBVnGC,the infiltration of activated CD4+T cells,activated CD8+T cells,monocytes,activated dendritic cells,and plasmacytoid dendritic cells were significantly upregulated in EBVaGC(P<0.001).In EBVaGC,the expression level of proinflammatory factors interleukin(IL)-17,IL-21,and interferon-γ and immunosuppressive factor IL-10 were significantly increased(P<0.05).In vitro experiments demonstrated that the expression level of IGFBP1 was significantly lower in an EBVaGC cell line(SNU719)than in an EBVnGC cell line(AGS)(P<0.05).IGFBP1 overexpression significantly attenuated proliferation and migration and promoted the apoptosis levels in SNU719.Interfering IGFBP1 significantly promoted proliferation and migration and attenuated the apoptosis levels in AGS.CONCLUSION m6A regulators could remodel the TME of EBVaGC,which is classified as an immune-inflamed phenotype and referred to as a“hot”tumor.Among these regulators,we demonstrated that IGFBP1 affected proliferation,migration,and apoptosis.展开更多
N^6-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 previo...N^6-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 P-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 fromβ-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.展开更多
N6-Methyladenosine(m6 A) modification is the most pervasive modification of human mRNA molecules. It is reversible via regulation of m6 A modification methyltransferase, demethylase and proteins that preferentially re...N6-Methyladenosine(m6 A) modification is the most pervasive modification of human mRNA molecules. It is reversible via regulation of m6 A modification methyltransferase, demethylase and proteins that preferentially recognize m6 A modification as "writers", "erasers" and "readers", respectively. Altered expression levels of the m6 A modification key regulators substantially affect their function, leading to significant phenotype changes in the cell and organism. Recent studies have proved that the m6 A modification plays significant roles in regulation of metabolism, stem cell self-renewal, and metastasis in a variety of human cancers. In this review, we describe the potential roles of m6 A modification in human cancers and summarize their underlying molecular mechanisms. Moreover, we will highlight potential therapeutic approaches by targeting the key m6 A modification regulators for cancer drug development.& 2018 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).展开更多
RNA modifications are abundant in eukaryotes, bacteria, and archaea. N^6-methyladenosine(m^6A), a type of RNA modification mainly found in messenger RNA(mRNA), has significant effects on the metabolism and function of...RNA modifications are abundant in eukaryotes, bacteria, and archaea. N^6-methyladenosine(m^6A), a type of RNA modification mainly found in messenger RNA(mRNA), has significant effects on the metabolism and function of m RNAs. This modification is governed by three types of proteins, namely methyltransferases as ‘‘writers' ', demethylases as ‘‘erasers' ',and specific m^6A-binding proteins(YTHDF1-3) as ‘‘readers' '. Further, it is important for the regulation of cell fate and has a critical function in many biological processes including virus replication, stem cell differentiation, and cancer development, and exerts its effect by controlling gene expression. Herein, we summarize recent advances in research on m^6A in virus replication and T cell regulation, which is a rapidly emerging field that will facilitate the development of antiviral therapies and the study of innate immunity.展开更多
N6-methyladenosine(m6A)modification is a reversible process promoted by“writers”,inhibited by“erasers”,and processed by“readers”.During the last decade,increasing emphasis has been placed on the underlying roles...N6-methyladenosine(m6A)modification is a reversible process promoted by“writers”,inhibited by“erasers”,and processed by“readers”.During the last decade,increasing emphasis has been placed on the underlying roles of m6A modification owing to their great importance in biological significance.The abnormal regulation of m6A modification will lead to aberrant cellular behavior and various diseases.Recently,studies have demonstrated that m6A modification is closely associated with the genesis and progression of ocular surface diseases(OSDs).This review focus on the role of m6A modification and research progress in OSDs including fungal keratitis,herpes simplex keratitis,immunerelated keratoconjunctival diseases,pterygium,ocular chemical burns,and Graves’ophthalmopathy,which may provide new insights into and prospective applications for OSDs.展开更多
Background Intramuscular fat(IMF)content is a critical indicator of pork quality,and abnormal IMF is also relevant to human disease as well as aging.Although N6-methyladenosine(m^(6)A)RNA modification was recently fou...Background Intramuscular fat(IMF)content is a critical indicator of pork quality,and abnormal IMF is also relevant to human disease as well as aging.Although N6-methyladenosine(m^(6)A)RNA modification was recently found to regulate adipogenesis in porcine intramuscular fat,however,the underlying molecular mechanisms was still unclear.Results In this work,we collected 20 longissimus dorsi muscle samples with high(average 3.95%)or low IMF content(average 1.22%)from a unique heterogenous swine population for m^(6)A sequencing(m^(6)A-seq).We discovered 70genes show both differential RNA expression and m^(6)A modification from high and low IMF group,including ADIPOQ and SFRP1,two hub genes inferred through gene co-expression analysis.Particularly,we observed ADIPOQ,which contains three m^(6)A modification sites within 3’untranslated and protein coding region,could promote porcine intramuscular preadipocyte differentiation in an m^(6)A-dependent manner.Furthermore,we found the YT521-B homology domain family protein 1(YTHDF1)could target and promote ADIPOQ mRNA translation.Conclusions Our study provided a comprehensive profiling of m^(6)A methylation in porcine longissimus dorsi muscle and characterized the involvement of m^(6)A epigenetic modification in the regulation of ADIPOQ mRNA on IMF deposition through an m^(6)A-YTHDF1-dependent manner.展开更多
BACKGROUND Cataracts remain a prime reason for visual disturbance and blindness all over the world,despite the capacity for successful surgical replacement with artificial lenses.Diabetic cataract(DC),a metabolic comp...BACKGROUND Cataracts remain a prime reason for visual disturbance and blindness all over the world,despite the capacity for successful surgical replacement with artificial lenses.Diabetic cataract(DC),a metabolic complication,usually occurs at an earlier age and progresses faster than age-related cataracts.Evidence has linked N6-methyladenosine(m6A)to DC progression.However,there exists a lack of understanding regarding RNA m6A modifications and the role of m6A in DC pathogenesis.AIM To elucidate the role played by altered m6A and differentially expressed mRNAs(DEmRNAs)in DC.METHODS Anterior lens capsules were collected from the control subjects and patients with DC.M6A epitranscriptomic microarray was performed to investigate the altered m6A modifications and determine the DEmRNAs.Through Gene Ontology and pathway enrichment(Kyoto Encyclopedia of Genes and Genomes)analyses,the potential role played by dysregulated m6A modification was predicted.Real-time polymerase chain reaction was further carried out to identify the dysregulated expression of RNA methyltransferases,demethylases,and readers.RESULTS Increased m6A abundance levels were found in the total mRNA of DC samples.Bioinformatics analysis predicted that ferroptosis pathways could be associated with m6A-modified mRNAs.The levels of five methylation-related genes-RBM15,WTAP,ALKBH5,FTO,and YTHDF1-were upregulated in DC samples.Upregulation of RBM15 expression was verified in SRA01/04 cells with high-glucose medium and in samples from DC patients.CONCLUSION M6a mRNA modifications may be involved in DC progression via the ferroptosis pathway,rendering novel insights into therapeutic strategies for DC.展开更多
Background:Stemness and chemoresistance contribute to cervical cancer recurrence and metastasis.In the current study,we determined the relevant players and role of N^(6)-methyladenine(m^(6)A)RNA methylation in cervica...Background:Stemness and chemoresistance contribute to cervical cancer recurrence and metastasis.In the current study,we determined the relevant players and role of N^(6)-methyladenine(m^(6)A)RNA methylation in cervical cancer progression.Methods:The roles of m^(6)A RNA methylation and centromere protein K(CENPK)in cervical cancer were analyzed using bioinformatics analysis.Methylated RNA immunoprecipitation was adopted to detect m^(6)A modification of CENPK mRNA.Human cervical cancer clinical samples,cell lines,and xenografts were used for analyzing gene expression and function.Immunofluorescence staining and the tumorsphere formation,clonogenic,MTT,and EdU assays were performed to determine cell stemness,chemoresistance,migration,invasion,and proliferation in HeLa and SiHa cells,respectively.Western blot analysis,co-immunoprecipitation,chromatin immunoprecipitation,and luciferase reporter,cycloheximide chase,and cell fractionation assays were performed to elucidate the underlying mechanism.Results:Bioinformatics analysis of public cancer datasets revealed firm links between m^(6)A modification patterns and cervical cancer prognosis,especially through ZC3H13-mediated m^(6)A modification of CENPK mRNA.CENPK expression was elevated in cervical cancer,associated with cancer recurrence,and independently predicts poor patient prognosis[hazard ratio=1.413,95%confidence interval=1.078−1.853,P=0.012].Silencing of CENPK prolonged the overall survival time of cervical cancer-bearing mice and improved the response of cervical cancer tumors to chemotherapy in vivo(P<0.001).We also showed that CENPK was directly bound to SOX6 and disrupted the interactions of CENPK withβ-catenin,which promotedβ-catenin expression and nuclear translocation,facilitated p53 ubiquitination,and led to activation of Wnt/β-catenin signaling,but suppression of the p53 pathway.This dysregulation ultimately enhanced the tumorigenic pathways required for cell stemness,DNA damage repair pathways necessary for cisplatin/carboplatin resistance,epithelial-mesenchymal transition involved in metastasis,and DNA replication that drove tumor cell proliferation.Conclusions:CENPK was shown to have an oncogenic role in cervical cancer and can thus serve as a prognostic indicator and novel target for cervical cancer treatment.展开更多
Impaired gene regulation lies at the heart of many disorders, including developmental diseases and cancer. Furthermore, the molecular pathways that control gene expression are often the target of cellular parasites, s...Impaired gene regulation lies at the heart of many disorders, including developmental diseases and cancer. Furthermore, the molecular pathways that control gene expression are often the target of cellular parasites, such as viruses. Gene expression is controlled through multiple mechanisms that are coordinated to ensure the proper and timely expression of each gene. Many of these mechanisms target the life cycle of the RNA molecule, from transcription to translation. Recently, another layer of regulation at the RNA level involving RNA modifications has gained renewed interest of the scientific community. The discovery that N6-methyladenosine (m6A), a mod- ification present in mRNAs and long noncoding RNAs, can be removed by the activity of RNA demethylases, launched the field of epitranscriptomics; the study of how RNA function is regulated through the addition or removal of post-transcriptional modifications, similar to strategies used to regulate gene expression at the DNA and protein level. The abundance of RNA post-transcriptional modifications is determined by the activity of writer complexes (methylase) and eraser (RNA demethylase) proteins. Subsequently, the effects of RNA modifications materialize as changes in RNA structure and/or modulation of interactions between the modified RNA and RNA binding proteins or regulatory RNAs. Disruption of these pathways impairs gene expression and cellular function. This review focuses on the links between the RNA modification m6A and its implications in human diseases.展开更多
Growing evidence supports that cancer progression is closely associated with the tumor microenvironment and immune evasion.Importantly,recent studies have revealed the crucial roles of epigenetic regulators in shaping...Growing evidence supports that cancer progression is closely associated with the tumor microenvironment and immune evasion.Importantly,recent studies have revealed the crucial roles of epigenetic regulators in shaping the tumor microenvironment and restoring immune recognition.N^(6)-methyladenosine(m^(6)A)modification,the most prevalent epigenetic modification of mammalian mRNAs,has essential functions in regulating the processing and metabolism of its targeted RNAs,and therefore affects various biological processes including tumorigenesis and progression.Recent studies have demonstrated the critical functions and molecular mechanisms underlying abnormal m^(6)A modification in the regulation of tumor immunity.In this review,we summarize recent research progress in the potential roles of m^(6)A modification in tumor immunoregulation,with a special focus on the anti-tumor processes of immune cells and involvement in immune-associated molecules and pathways.Furthermore,we review current knowledge regarding the close correlation between m6A-related risk signatures and the tumor immune microenvironment landscape,and we discuss the prognostic value and therapeutic efficacy of m^(6)A regulators in a variety of cancer types.展开更多
The biological roles of N6 methylation of nucleic acids have been extensively studied.Adenine methylation of RNA is the most prevalent RNA modification and has widespread effects on RNA splicing,translation,localizati...The biological roles of N6 methylation of nucleic acids have been extensively studied.Adenine methylation of RNA is the most prevalent RNA modification and has widespread effects on RNA splicing,translation,localization,and stability.Aberrant dynamic regulation of RNA N6-methyladenosine(m6 A)has been reported in numerous human diseases,including several cancers.In recent years,eukaryotic DNA N6-methyladenosine(6 mA)has also been reported and implicated in cancer progression and tumorigenesis.In this review,we summarize the contributions of N6-methyladenosine modification to cancer biology and pathogenesis in the context of both RNA and DNA.We also highlight the clinical relevance of targeting these modifications as a therapeutic strategy for cancer.展开更多
BACKGROUND Severe acute pancreatitis(SAP)is a deadly inflammatory disease with complex pathogenesis and lack of effective therapeutic options.N6-methyladenosine(m6A)modification of circRNAs plays important roles in ph...BACKGROUND Severe acute pancreatitis(SAP)is a deadly inflammatory disease with complex pathogenesis and lack of effective therapeutic options.N6-methyladenosine(m6A)modification of circRNAs plays important roles in physiological and pathological processes.However,the roles of m6A circRNA in the pathological process of SAP remains unknown.AIM To identify transcriptome-wide map of m6A circRNAs and to determine their biological significance and potential mechanisms in SAP.METHODS The SAP in C57BL/6 mice was induced using 4%sodium taurocholate salt.The transcriptome-wide map of m6A circRNAs was identified by m6A-modified RNA immunoprecipitation sequencing.The biological significance of circRNAs with differentially expressed m6A peaks was evaluated through gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis.The underlying mechanism of m6A circRNAs in SAP was analyzed by constructing of m6A circRNAmicroRNA networks.The expression of demethylases was determined by quantitative polymerase chain reaction and western blot to deduce the possible mechanism of reversible m6A process in SAP.RESULTS Fifty-seven circRNAs with differentially expressed m6A peaks were identified by m6A-modified RNA immunoprecipitation sequencing,of which 32 were upregulated and 25 downregulated.Functional analysis of these m6A circRNAs in SAP found some important pathways involved in the pathogenesis of SAP,such as regulation of autophagy and protein digestion.In m6A circRNA–miRNA networks,several important miRNAs participated in the occurrence and progression of SAP were found to bind to these m6A circRNAs,such as miR-24-3p,miR-26a,miR-92b,miR-216b,miR-324-5p and miR-762.Notably,the total m6A level of circRNAs was reduced,while the demethylase alkylation repair homolog 5 was upregulated in SAP.CONCLUSION m6A modification of circRNAs may be involved in the pathogenesis of SAP.Our findings may provide novel insights to explore the possible pathogenetic mechanism of SAP and seek new potential therapeutic targets for SAP.展开更多
基金Supported by National Natural Science Foundation of China,No.81802450and Natural Science Foundation of Hunan Province,No.2020JJ4133 and No.2021JJ31135.
文摘BACKGROUND Increasing evidence has demonstrated that N6-methyladenosine(m6A)RNA modification plays an essential role in a wide range of pathological conditions.Impaired autophagy is a critical hallmark of acute pancreatitis(AP).AIM To explore the role of the m6A modification of ZKSCAN3 in the regulation of autophagy in AP.METHODS The AP mouse cell model was established by cerulein-treated mouse pancreatic acinar cells(MPC-83),and the results were confirmed by the levels of amylase and inflammatory factors.Autophagy activity was evaluated by specific identification of the autophagy-related microstructure and the expression of autophagy-related genes.ZKSCAN3 and ALKBH5 were knocked down to study the function in AP.A m6A RNA binding protein immunoprecipitation assay was used to study how the m6A modification of ZKSCAN3 mRNA is regulated by ALKBH.RESULTS The increased expression of amylase and inflammatory factors in the supernatant and the accumulation of autophagic vacuoles verified that the AP mouse cell model was established.The downregulation of LAMP2 and upregulation of LC3-II/I and SQSTM1 demonstrated that autophagy was impaired in AP.The expression of ZKSCAN3 was upregulated in AP.Inhibition of ZKSCAN3 increased the expression of LAMP2 and decreased the expression of the inflammatory factors,LC3-II/I and SQSTM1.Furthermore,ALKBH5 was upregulated in AP.Knockdown of ALKBH5 downregulated ZKSCAN3 expression and restored decreased autophagic flux in AP.Notably,the bioinformatic analysis revealed 23 potential m6A modification sites on ZKSCAN3 mRNA.The m6A modification of ZKSCAN3 mRNA was significantly decreased in AP.Knockdown of ALKBH5 increased the modification of ZKSCAN3 mRNA,which confirmed that ALKBH5 upregulated ZKSCAN3 expression in a m6A-dependent manner.CONCLUSION ALKBH5 inhibits autophagic flux through m6A demethylation of ZKSCAN3 mRNA in AP,thereby aggravating the severity of the disease.
基金Key Project Research and Development Plan of Hainan Province(No.ZDYF2020134,ZDYF2022SHFZ283)Natural Science Foundation of Hainan Province(No.821QN391)。
文摘N6-methyladenosine(m6A)is a reversible epigenetic modification, which is one of the most abundant modifiers in eukaryotic cells and has been commonly reported in messenger RNAs and non-coding RNAs. The processing modification of m6A regulates RNA transcription, processing, splicing, degradation, and translation, and plays an important role in the biological process of tumors. Circular RNA, which lacks the 5' cap structure, has been mistakenly regarded as a "junk sequence" generated by accidental shearing during the transcription process. However, it has been found that circRNAs can be involved in tumor invasion and metastasis through microRNAs, binding proteins, translated peptides, and m6A modifications. In this paper, we reviewed the role of m6A modifications in circRNA regulation and their functions in hepatocellular carcinoma and discussed their potential clinical applications and future development in this field.
基金Supported by the Sub-Project of the National Key Research and Development Program,No.2021YFC2600263.
文摘BACKGROUND N6-methyladenosine(m6A)methylation modification exists in Epstein-Barr virus(EBV)primary infection,latency,and lytic reactivation.It also modifies EBV latent genes and lytic genes.EBV-associated gastric cancer(EBVaGC)is a distinctive molecular subtype of GC.We hypothesized EBV and m6A methylation regulators interact with each other in EBVaGC to differentiate it from other types of GC.AIM To investigate the mechanisms of m6A methylation regulators in EBVaGC to determine the differentiating factors from other types of GC.METHODS First,The Cancer Gene Atlas and Gene Expression Omnibus databases were used to analyze the expression pattern of m6A methylation regulators between EBVaGC and EBV-negative GC(EBVnGC).Second,we identified Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)functional enrichment of m6A-related differentially expressed genes.We quantified the relative abundance of immune cells and inflammatory factors in the tumor microenvironment(TME).Finally,cell counting kit-8 cell proliferation test,transwell test,and flow cytometry were used to verify the effect of insulin-like growth factor binding protein 1(IGFBP1)in EBVaGC cell lines.RESULTS m6A methylation regulators were involved in the occurrence and development of EBVaGC.Compared with EBVnGC,the expression levels of m6A methylation regulators Wilms tumor 1-associated protein,RNA binding motif protein 15B,CBL proto-oncogene like 1,leucine rich pentatricopeptide repeat containing,heterogeneous nuclear ribonucleoprotein A2B1,IGFBP1,and insulin-like growth factor 2 binding protein 1 were significantly downregulated in EBVaGC(P<0.05).The overall survival rate of EBVaGC patients with a lower expression level of IGFBP1 was significantly higher(P=0.046).GO and KEGG functional enrichment analyses showed that the immunity pathways were significantly activated and rich in immune cell infiltration in EBVaGC.Compared with EBVnGC,the infiltration of activated CD4+T cells,activated CD8+T cells,monocytes,activated dendritic cells,and plasmacytoid dendritic cells were significantly upregulated in EBVaGC(P<0.001).In EBVaGC,the expression level of proinflammatory factors interleukin(IL)-17,IL-21,and interferon-γ and immunosuppressive factor IL-10 were significantly increased(P<0.05).In vitro experiments demonstrated that the expression level of IGFBP1 was significantly lower in an EBVaGC cell line(SNU719)than in an EBVnGC cell line(AGS)(P<0.05).IGFBP1 overexpression significantly attenuated proliferation and migration and promoted the apoptosis levels in SNU719.Interfering IGFBP1 significantly promoted proliferation and migration and attenuated the apoptosis levels in AGS.CONCLUSION m6A regulators could remodel the TME of EBVaGC,which is classified as an immune-inflamed phenotype and referred to as a“hot”tumor.Among these regulators,we demonstrated that IGFBP1 affected proliferation,migration,and apoptosis.
文摘N^6-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 P-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 fromβ-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.
基金supported in part by a grant from the National Natural Science Foundation of China (No. 31701114)the Fundamental Research Funds for University-Key Cultivation Project of Young Teacher in Sun Yat-Sen University (No. 17ykzd11)
文摘N6-Methyladenosine(m6 A) modification is the most pervasive modification of human mRNA molecules. It is reversible via regulation of m6 A modification methyltransferase, demethylase and proteins that preferentially recognize m6 A modification as "writers", "erasers" and "readers", respectively. Altered expression levels of the m6 A modification key regulators substantially affect their function, leading to significant phenotype changes in the cell and organism. Recent studies have proved that the m6 A modification plays significant roles in regulation of metabolism, stem cell self-renewal, and metastasis in a variety of human cancers. In this review, we describe the potential roles of m6 A modification in human cancers and summarize their underlying molecular mechanisms. Moreover, we will highlight potential therapeutic approaches by targeting the key m6 A modification regulators for cancer drug development.& 2018 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).
基金supported by funding from the National Natural Science Foundation of China (Nos. 81672004, 31270202,81801993, and 81801994)the Jilin University Science and Technology Innovative Research Team (JLUSTIRT, 2017TD-05)+3 种基金the Science and Technology Department of Jilin Province (20160101044JC)the Health and Family Planning Commission of Jilin Province (2013Z066)the Key Laboratory of Molecular Virology, Jilin Province (20102209)China Postdocotoral Science Foundation (2018M631869)
文摘RNA modifications are abundant in eukaryotes, bacteria, and archaea. N^6-methyladenosine(m^6A), a type of RNA modification mainly found in messenger RNA(mRNA), has significant effects on the metabolism and function of m RNAs. This modification is governed by three types of proteins, namely methyltransferases as ‘‘writers' ', demethylases as ‘‘erasers' ',and specific m^6A-binding proteins(YTHDF1-3) as ‘‘readers' '. Further, it is important for the regulation of cell fate and has a critical function in many biological processes including virus replication, stem cell differentiation, and cancer development, and exerts its effect by controlling gene expression. Herein, we summarize recent advances in research on m^6A in virus replication and T cell regulation, which is a rapidly emerging field that will facilitate the development of antiviral therapies and the study of innate immunity.
基金Supported by Project of Shanghai Science and Technology (No.20ZR1443600)。
文摘N6-methyladenosine(m6A)modification is a reversible process promoted by“writers”,inhibited by“erasers”,and processed by“readers”.During the last decade,increasing emphasis has been placed on the underlying roles of m6A modification owing to their great importance in biological significance.The abnormal regulation of m6A modification will lead to aberrant cellular behavior and various diseases.Recently,studies have demonstrated that m6A modification is closely associated with the genesis and progression of ocular surface diseases(OSDs).This review focus on the role of m6A modification and research progress in OSDs including fungal keratitis,herpes simplex keratitis,immunerelated keratoconjunctival diseases,pterygium,ocular chemical burns,and Graves’ophthalmopathy,which may provide new insights into and prospective applications for OSDs.
基金supported by funds from the National Natural Science Foundation of China (Grant No.U21A20249)China Postdoctoral Science Foundation (2022 M712794)。
文摘Background Intramuscular fat(IMF)content is a critical indicator of pork quality,and abnormal IMF is also relevant to human disease as well as aging.Although N6-methyladenosine(m^(6)A)RNA modification was recently found to regulate adipogenesis in porcine intramuscular fat,however,the underlying molecular mechanisms was still unclear.Results In this work,we collected 20 longissimus dorsi muscle samples with high(average 3.95%)or low IMF content(average 1.22%)from a unique heterogenous swine population for m^(6)A sequencing(m^(6)A-seq).We discovered 70genes show both differential RNA expression and m^(6)A modification from high and low IMF group,including ADIPOQ and SFRP1,two hub genes inferred through gene co-expression analysis.Particularly,we observed ADIPOQ,which contains three m^(6)A modification sites within 3’untranslated and protein coding region,could promote porcine intramuscular preadipocyte differentiation in an m^(6)A-dependent manner.Furthermore,we found the YT521-B homology domain family protein 1(YTHDF1)could target and promote ADIPOQ mRNA translation.Conclusions Our study provided a comprehensive profiling of m^(6)A methylation in porcine longissimus dorsi muscle and characterized the involvement of m^(6)A epigenetic modification in the regulation of ADIPOQ mRNA on IMF deposition through an m^(6)A-YTHDF1-dependent manner.
基金Supported by the National Natural Science Foundation of China,No.82171039.
文摘BACKGROUND Cataracts remain a prime reason for visual disturbance and blindness all over the world,despite the capacity for successful surgical replacement with artificial lenses.Diabetic cataract(DC),a metabolic complication,usually occurs at an earlier age and progresses faster than age-related cataracts.Evidence has linked N6-methyladenosine(m6A)to DC progression.However,there exists a lack of understanding regarding RNA m6A modifications and the role of m6A in DC pathogenesis.AIM To elucidate the role played by altered m6A and differentially expressed mRNAs(DEmRNAs)in DC.METHODS Anterior lens capsules were collected from the control subjects and patients with DC.M6A epitranscriptomic microarray was performed to investigate the altered m6A modifications and determine the DEmRNAs.Through Gene Ontology and pathway enrichment(Kyoto Encyclopedia of Genes and Genomes)analyses,the potential role played by dysregulated m6A modification was predicted.Real-time polymerase chain reaction was further carried out to identify the dysregulated expression of RNA methyltransferases,demethylases,and readers.RESULTS Increased m6A abundance levels were found in the total mRNA of DC samples.Bioinformatics analysis predicted that ferroptosis pathways could be associated with m6A-modified mRNAs.The levels of five methylation-related genes-RBM15,WTAP,ALKBH5,FTO,and YTHDF1-were upregulated in DC samples.Upregulation of RBM15 expression was verified in SRA01/04 cells with high-glucose medium and in samples from DC patients.CONCLUSION M6a mRNA modifications may be involved in DC progression via the ferroptosis pathway,rendering novel insights into therapeutic strategies for DC.
基金the Joint Funds for the Innovation of Science and Technology Program of Fujian Province,China(2018Y9110)the Natural Science Foundation of Fujian Province,China,(2020J011126)the China Postdoctoral Science Foundation(2021T140468).
文摘Background:Stemness and chemoresistance contribute to cervical cancer recurrence and metastasis.In the current study,we determined the relevant players and role of N^(6)-methyladenine(m^(6)A)RNA methylation in cervical cancer progression.Methods:The roles of m^(6)A RNA methylation and centromere protein K(CENPK)in cervical cancer were analyzed using bioinformatics analysis.Methylated RNA immunoprecipitation was adopted to detect m^(6)A modification of CENPK mRNA.Human cervical cancer clinical samples,cell lines,and xenografts were used for analyzing gene expression and function.Immunofluorescence staining and the tumorsphere formation,clonogenic,MTT,and EdU assays were performed to determine cell stemness,chemoresistance,migration,invasion,and proliferation in HeLa and SiHa cells,respectively.Western blot analysis,co-immunoprecipitation,chromatin immunoprecipitation,and luciferase reporter,cycloheximide chase,and cell fractionation assays were performed to elucidate the underlying mechanism.Results:Bioinformatics analysis of public cancer datasets revealed firm links between m^(6)A modification patterns and cervical cancer prognosis,especially through ZC3H13-mediated m^(6)A modification of CENPK mRNA.CENPK expression was elevated in cervical cancer,associated with cancer recurrence,and independently predicts poor patient prognosis[hazard ratio=1.413,95%confidence interval=1.078−1.853,P=0.012].Silencing of CENPK prolonged the overall survival time of cervical cancer-bearing mice and improved the response of cervical cancer tumors to chemotherapy in vivo(P<0.001).We also showed that CENPK was directly bound to SOX6 and disrupted the interactions of CENPK withβ-catenin,which promotedβ-catenin expression and nuclear translocation,facilitated p53 ubiquitination,and led to activation of Wnt/β-catenin signaling,but suppression of the p53 pathway.This dysregulation ultimately enhanced the tumorigenic pathways required for cell stemness,DNA damage repair pathways necessary for cisplatin/carboplatin resistance,epithelial-mesenchymal transition involved in metastasis,and DNA replication that drove tumor cell proliferation.Conclusions:CENPK was shown to have an oncogenic role in cervical cancer and can thus serve as a prognostic indicator and novel target for cervical cancer treatment.
基金supported by the Intramural Research Program of the NIH,National Cancer Institute,Center for Cancer Research,United States of America
文摘Impaired gene regulation lies at the heart of many disorders, including developmental diseases and cancer. Furthermore, the molecular pathways that control gene expression are often the target of cellular parasites, such as viruses. Gene expression is controlled through multiple mechanisms that are coordinated to ensure the proper and timely expression of each gene. Many of these mechanisms target the life cycle of the RNA molecule, from transcription to translation. Recently, another layer of regulation at the RNA level involving RNA modifications has gained renewed interest of the scientific community. The discovery that N6-methyladenosine (m6A), a mod- ification present in mRNAs and long noncoding RNAs, can be removed by the activity of RNA demethylases, launched the field of epitranscriptomics; the study of how RNA function is regulated through the addition or removal of post-transcriptional modifications, similar to strategies used to regulate gene expression at the DNA and protein level. The abundance of RNA post-transcriptional modifications is determined by the activity of writer complexes (methylase) and eraser (RNA demethylase) proteins. Subsequently, the effects of RNA modifications materialize as changes in RNA structure and/or modulation of interactions between the modified RNA and RNA binding proteins or regulatory RNAs. Disruption of these pathways impairs gene expression and cellular function. This review focuses on the links between the RNA modification m6A and its implications in human diseases.
基金This research was supported by grants from the National Natural Science Foundation of China(Grant Nos.81922052,81974435,and 81772999)Natural Science Foundation of Guangdong Province(Grant No.2019B151502011)the Guangzhou People’s Livelihood Science and Technology Project(Grant No.201903010006).
文摘Growing evidence supports that cancer progression is closely associated with the tumor microenvironment and immune evasion.Importantly,recent studies have revealed the crucial roles of epigenetic regulators in shaping the tumor microenvironment and restoring immune recognition.N^(6)-methyladenosine(m^(6)A)modification,the most prevalent epigenetic modification of mammalian mRNAs,has essential functions in regulating the processing and metabolism of its targeted RNAs,and therefore affects various biological processes including tumorigenesis and progression.Recent studies have demonstrated the critical functions and molecular mechanisms underlying abnormal m^(6)A modification in the regulation of tumor immunity.In this review,we summarize recent research progress in the potential roles of m^(6)A modification in tumor immunoregulation,with a special focus on the anti-tumor processes of immune cells and involvement in immune-associated molecules and pathways.Furthermore,we review current knowledge regarding the close correlation between m6A-related risk signatures and the tumor immune microenvironment landscape,and we discuss the prognostic value and therapeutic efficacy of m^(6)A regulators in a variety of cancer types.
基金supported by a grant from Westlake University Startup Funding(Grant No.101476021901)。
文摘The biological roles of N6 methylation of nucleic acids have been extensively studied.Adenine methylation of RNA is the most prevalent RNA modification and has widespread effects on RNA splicing,translation,localization,and stability.Aberrant dynamic regulation of RNA N6-methyladenosine(m6 A)has been reported in numerous human diseases,including several cancers.In recent years,eukaryotic DNA N6-methyladenosine(6 mA)has also been reported and implicated in cancer progression and tumorigenesis.In this review,we summarize the contributions of N6-methyladenosine modification to cancer biology and pathogenesis in the context of both RNA and DNA.We also highlight the clinical relevance of targeting these modifications as a therapeutic strategy for cancer.
基金the National Natural Science Foundation of China,No.81772001the National Clinical Key Subject of China,No.41732113.
文摘BACKGROUND Severe acute pancreatitis(SAP)is a deadly inflammatory disease with complex pathogenesis and lack of effective therapeutic options.N6-methyladenosine(m6A)modification of circRNAs plays important roles in physiological and pathological processes.However,the roles of m6A circRNA in the pathological process of SAP remains unknown.AIM To identify transcriptome-wide map of m6A circRNAs and to determine their biological significance and potential mechanisms in SAP.METHODS The SAP in C57BL/6 mice was induced using 4%sodium taurocholate salt.The transcriptome-wide map of m6A circRNAs was identified by m6A-modified RNA immunoprecipitation sequencing.The biological significance of circRNAs with differentially expressed m6A peaks was evaluated through gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis.The underlying mechanism of m6A circRNAs in SAP was analyzed by constructing of m6A circRNAmicroRNA networks.The expression of demethylases was determined by quantitative polymerase chain reaction and western blot to deduce the possible mechanism of reversible m6A process in SAP.RESULTS Fifty-seven circRNAs with differentially expressed m6A peaks were identified by m6A-modified RNA immunoprecipitation sequencing,of which 32 were upregulated and 25 downregulated.Functional analysis of these m6A circRNAs in SAP found some important pathways involved in the pathogenesis of SAP,such as regulation of autophagy and protein digestion.In m6A circRNA–miRNA networks,several important miRNAs participated in the occurrence and progression of SAP were found to bind to these m6A circRNAs,such as miR-24-3p,miR-26a,miR-92b,miR-216b,miR-324-5p and miR-762.Notably,the total m6A level of circRNAs was reduced,while the demethylase alkylation repair homolog 5 was upregulated in SAP.CONCLUSION m6A modification of circRNAs may be involved in the pathogenesis of SAP.Our findings may provide novel insights to explore the possible pathogenetic mechanism of SAP and seek new potential therapeutic targets for SAP.