ALKBH5 suppresses autophagic flux via N6-methyladenosine demethylation of ZKSCAN3 mRNA in acute pancreatitis

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.

Profiling of N6-methyladenosine methylation in porcine longissimus dorsi muscle and unravelling the hub gene ADIPOQ promotes adipogenesis in an m^(6)A-YTHDF1–dependent manner

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.

Recent progress in N6-methyladenosine modification in ocular surface diseases

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.

Analysis of N6-methyladenosine-modified mRNAs in diabetic cataract

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.

m^(6)A甲基化修饰在眼科疾病中的研究进展

N6-甲基腺苷(m^(6)A)是真核细胞中最普遍、最丰富和最保守的RNA内部修饰方式。m^(6)A修饰主要通过m^(6)A甲基转移酶、m^(6)A去甲基化酶和m^(6)A甲基化识别蛋白调节RNA的剪接、稳定性、输出、降解和翻译等。近年来的研究发现,m^(6)A甲基化异常可能介导眼部的多种病理过程,参与代谢性、炎症性、退行性眼病和眼部肿瘤的发生发展,如糖尿病视网膜病变、白内障、年龄相关性黄斑变性、葡萄膜黑色素瘤等。本文就m^(6)A甲基化修饰在眼部组织细胞和眼科疾病中的作用进行综述,阐明m^(6)A甲基化在眼病中的潜在分子机制,可能为某些眼科疾病的患者提供新的治疗思路。

N^(6)-methyladenosine(m^(6)A)RNA modification in tumor immunity

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.

Epigenetic N6-methyladenosine modification of RNA and DNA regulates cancer

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.

Genome-wide map of N6-methyladenosine circular RNAs identified in mice model of severe acute pancreatitis

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.

N6-甲基腺嘌呤修饰在恶性肿瘤发生发展及治疗中的研究进展

近年来RNA修饰引起了全世界生物学家的广泛关注。到目前为止已发现170余个RNA修饰,其中N6-甲基腺嘌呤(m^(6)A)是mRNA最主要的修饰方式之一。它调节RNA的剪接、转位、翻译和稳定性,在细胞的生长、分化和代谢中起着至关重要的作用。作为一种动态、可逆的修饰,m^(6)A的表达水平受RNA甲基转移酶、去甲基酶以及m^(6)A结合蛋白的共同调节。越来越多的研究表明m^(6)A基因修饰与人类癌症的发生发展关系密切。本文就m^(6)A异常修饰在多种恶性肿瘤发生发展及治疗中的研究进展进行综述,旨在为癌症治疗提供新的思路。

EZH2 Contributes to Anoikis Resistance and Promotes Epithelial Ovarian Cancer Peritoneal Metastasis by Regulating m6A

Objective:Histone modification has a significant effect on gene expression.Enhancer of zeste homolog 2(EZH2)contributes to the epigenetic silencing of target chromatin through its roles as a histone-lysine N-methyltransferase enzyme.The development of anoikis resistance in tumor cells is considered to be a critical step in the metastatic process of primary malignant tumors.The purpose of this study was to investigate the effect and mechanism of anoikis resistance in ovarian adenocarcinoma peritoneal metastasis.Methods:In addition to examining EZH2 protein expression in ovarian cancer omental metastatic tissues,we established a model of ovarian cancer cell anoikis and a xenograft tumor model in nude mice.Anoikis resistance and ovarian cancer progression were tested after EZH2 and N6-methyladenosine(m6A)levels were modified.Results:EZH2 expression was significantly higher in ovarian cancer omental metastatic tissues than in normal ovarian tissues.Reducing the level of EZH2 decreased the level of m6A and ovarian cancer cell anoikis resistance in vitro and inhibited ovarian cancer progression in vivo.M6a regulation altered the effect of EZH2 on anoikis resistance.Conclusion:Our results indicate that EZH2 contributes to anoikis resistance and promotes ovarian adenocarcinoma abdominal metastasis by m6A modification.Our findings imply the potential of the clinical application of m6A and EZH2 for patients with ovarian cancer.

m^(6)A甲基化转移酶3在糖尿病性白内障发病中的作用机制

目的:探讨N6-甲基腺嘌呤(N6-methyladenosine,m^(6)A)甲基化转移酶3(METTL3)在糖尿病性白内障发病中的作用机制。方法:用低糖和高糖培养基培养人晶状体上皮细胞系(SRA01/04)24h后,采用RT-qPCR和Western blot实验检测细胞的上皮-间质转分化(EMT)指标:E-钙黏蛋白(E-Cadherin)、N-钙黏蛋白(N-Cadherin)、紧密连接蛋白1(ZO-1)和α-平滑肌肌动蛋白(α-SMA)的变化情况;transwell和划痕实验检测细胞迁移能力。采用免疫荧光染色检测人晶状体前囊膜组织中METTL3的表达量及定位,m^(6)A dot blot实验检测在低糖和高糖培养基中培养24h细胞的m^(6)A甲基化水平,RT-qPCR和Western blot实验检测细胞中METTL3的RNA和蛋白表达量。加入METTL3抑制剂的培养基中培养24h的细胞,RT-qPCR和Western blot实验检测EMT指标的变化情况;m^(6)A dot blot实验检测细胞m^(6)A甲基化水平;Transwell和划痕实验检测细胞迁移能力。免疫荧光染色检测细胞中转化生成因子β(TGFβ1)的表达;RT-qPCR和Western blot实验检测细胞中的TGFβ1和SNAIL的表达量。结果:与低糖条件相比,高糖条件能够促进细胞EMT的发生,促进METTL3的表达和上调了细胞总RNA的m^(6)A甲基化水平(P<0.05)。高糖能够促进细胞的迁移能力。糖尿病性白内障患者晶状体前囊膜中METTL3表达较单纯年龄相关性白内障患者增高。与高糖+DMSO组相比,加入METTL3抑制剂STM2457,能够抑制细胞的EMT发生,抑制TGFβ1和SNAIL的表达,抑制细胞总RNA的m^(6)A甲基化水平(均P<0.05)。加入METTL3抑制剂STM2457后细胞迁移能力较高糖+DMSO组降低。结论:m^(6)A甲基化转移酶METTL3通过激活TGFβ1/SNAIL通路促进了在高糖条件下人晶状体上皮细胞的EMT发生从而诱导糖尿病性白内障的发生。

Aberrant expression of enzymes regulating m^6A mRNA methylation: implication in cancer

N^6-methyladenosine(m^6 A) is an essential RNA modification that regulates key cellular processes, including stem cell renewal,cellular differentiation, and response to DNA damage. Unsurprisingly, aberrant m^6 A methylation has been implicated in the development and maintenance of diverse human cancers. Altered m^6 A levels affect RNA processing, mRNA degradation, and translation of mRNAs into proteins, thereby disrupting gene expression regulation and promoting tumorigenesis. Recent studies have reported that the abnormal expression of m^6 A regulatory enzymes affects m^6 A abundance and consequently dysregulates the expression of tumor suppressor genes and oncogenes, including MYC, SOCS2, ADAM19, and PTEN. In this review, we discuss the specific roles of m^6 A missing space "writers", "erasers", and "readers" in normal physiology and how their altered expression promotes tumorigenesis. We also describe the potential of exploiting the aberrant expression of these enzymes for cancer diagnosis, prognosis, and the development of novel therapies.

Meclofenamic acid represses spermatogonial proliferation through modulating m^6A RNA modification

Background: N6-Methyladenosine(m^6A), the most prevalent modification in mammalian m RNA, plays important roles in numerous biological processes. Several m^6A associated proteins such as methyltransferase like 3(METTL3),methyltransferase like 14(METTL14), α-ketoglutarate-dependent dioxygenase Alk B homolog 5(ALKBH5) and YTH domain containing 2(YTHDC2) are involved in the regulation of spermatogenesis and oogenesis. However, the role of the first detected m^6A demethylase, fat mass and obesity associate protein(FTO), in germ cells remains elusive.Elucidation of FTO roles in the regulation of germ cell fate will provide novel insights into the mammalian reproduction.Methods: Mouse GC-1 spg cells were treated with the ester form of meclofenamic acid(MA2) to inhibit the demethylase activity of FTO. The cellular m^6A and m^6Amlevel were analyzed through high performance liquid chromatography combined with tandem mass spectrometry(HPLC/MS-MS). The cell apoptosis was detected via TUNEL and flow cytometry. The cell proliferation was detected through Ed U and western blot. The m RNA level of core cyclin dependent kinases(CDKs) was quantified via q-PCR. RNA decay assay were performed to detect RNA stability. Dual fluorescence assay was conducted to study whether MA2 affects the expression of CDK2 dependent on the m^6A modification at 3’UTR.Results: MA2 significantly increased the cellular m^6A level and down-regulated the expression of CDK1, CDK2, CDK6 and Cd C25 a, resulting in arrest of G1/S transition and decrease of cell proliferation. MA2 downregulated CDK2 m RNA stability. Additionally, mutation of the predicted m^6A sites in the Cdk2–3’UTR could mitigated the degradation of CDK2 m RNA after MA2 treatment.Conclusion: MA2 affected CDKs expression through the m^6A-dependent m RNA degradation pathway, and thus repressed spermatogonial proliferation.

N^6-甲基腺嘌呤RNA修饰研究进展

N^6-甲基腺嘌呤(N^6-methyladenosine,m6A)作为一种重要的表观遗传修饰方式,在干细胞命运决定、精子形成、肌肉发育、脂肪沉积及人类肿瘤发生中发挥重要作用。m^6A修饰最重要的作用是调控基因表达,它是细胞中基因表达调控的表观遗传学机制之一。文章综述了m^6A调控基因表达的分子机制及m^6A介导的生物学功能的研究进展,探讨了m^6A RNA甲基化的研究趋势和未来发展方向。

猪m^(6)A甲基化酶WTAP基因与F18大肠杆菌感染的关系

本研究旨在探讨猪m 6A甲基化酶WTAP表达水平与大肠杆菌(E.coli)感染抗性的关系。选取35日龄苏太断奶仔猪(Sus scrofa)大肠杆菌抗性型和敏感型个体各4头,采集十二指肠和空肠组织,利用RT-qPCR检测WTAP在E.coli抗性型和敏感型个体十二指肠、空肠的表达差异,并分别利用产肠毒素大肠杆菌(F18ab、F18ac)刺激和内毒素(LPS)诱导猪小肠上皮细胞(IPEC-J2),检测WTAP基因的表达变化。同时构建WTAP基因干扰载体并转染IPEC-J2细胞,通过菌毛定量、菌落计数以及间接免疫荧光试验检测该基因沉默对大肠杆菌黏附能力的影响。结果显示:在十二指肠和空肠组织中,WTAP基因在E.coli抗性型个体中的表达量显著高于敏感型个体(P<0.01);并且在F18ab和F18ac刺激后表达量显著下降,与LPS诱导6 h后结果相一致(P<0.01)。沉默WTAP基因后,大肠杆菌黏附能力极显著上升(P<0.01)。本研究在细胞和个体水平上验证发现,m 6A甲基转移酶WTAP的高表达可能有助于仔猪抗大肠杆菌感染,为进一步揭示仔猪抗大肠杆菌感染的RNA甲基化调控机制奠定基础。

N6-methyladenosine methylation regulates the tumor microenvironment of Epstein-Barr virus-associated gastric cancer

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.

Advances of N6-methyladenosine modification on circular RNA in hepatocellular carcinoma

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.

N6-甲基腺嘌呤与癌症的研究进展

N6-甲基腺嘌呤(m^6A)作为一种主要的RNA甲基化修饰,通过多种机制影响人类癌症的发生和发展。m^6A修饰影响RNA代谢的多个方面,从RNA加工、核输出、RNA翻译到衰变。在这篇综述中,介绍了m^6A甲基化基本概念,m^6A甲基转移酶复合物和m^6A去甲基化酶在几种主要癌症中的调控作用和一些作为m^6A结合蛋白的蛋白质执行的m^6A修饰的生物学功能。此外,还讨论了m^6A甲基化的双重作用以及它在临床应用中的潜力。

The m^(6)A reader YTHDC2 maintains visual function and retinal photoreceptor survival through modulating translation of PPEF2 and PDE6B

Inherited retinal dystrophies (IRDs) are major causes of visual impairment and irreversible blindness worldwide, while the precise molecular and genetic mechanisms are still elusive. N6-methyladenosine (m^(6)A) modification is the most prevalent internal modification in eukaryotic mRNA. YTH domain containing 2 (YTHDC2), an m^(6)A reader protein, has recently been identified as a key player in germline development and human cancer. However, its contribution to retinal function remains unknown. Here, we explore the role of YTHDC2 in the visual function of retinal rod photoreceptors by generating rod-specific Ythdc2 knockout mice. Results show that Ythdc2 deficiency in rods causes diminished scotopic ERG responses and progressive retinal degeneration. Multi-omics analysis further identifies Ppef2 and Pde6b as the potential targets of YTHDC2 in the retina. Specifically, via its YTH domain, YTHDC2 recognizes and binds m^(6)A-modified Ppef2 mRNA at the coding sequence and Pde6b mRNA at the 5′-UTR, resulting in enhanced translation efficiency without affecting mRNA levels. Compromised translation efficiency of Ppef2 and Pde6b after YTHDC2 depletion ultimately leads to decreased protein levels in the retina, impaired retinal function, and progressive rod death. Collectively, our finding highlights the importance of YTHDC2 in visual function and photoreceptor survival, which provides an unreported elucidation of IRD pathogenesis via epitranscriptomics.

The m6A writers regulated by the IL-6/STAT3 inflammatory pathway facilitate cancer cell stemness in cholangiocarcinoma

Objective:Investigation of the regulatory mechanisms of cell stemness in cholangiocarcinoma(CCA)is essential for developing effective therapies to improve patient outcomes.The purpose of this study was to investigate the function and regulatory mechanism of m6A modifications in CCA cell stemness.Methods:Interleukin 6(IL-6)treatment was used to induce an inflammatory response,and loss-of-function studies were conducted using mammosphere culture assays.Chromatin immunoprecipitation,polysome profiling,and methylated RNA immunoprecipitation analyses were used to identify signaling pathways.The in vitro findings were verified in a mice model.Results:We first identified that m6A writers were highly expressed in CCAs and further showed that STAT3 directly bound to the gene loci of m6A writers,showing that IL-6/STAT3 signaling regulated expressions of m6A writers.Downregulating m6A writers prevented cell proliferation and migration in vitro and suppressed CCA tumorigenesis in vivo.Notably,the knockdown of m6A writers inhibited CCA cell stemness that was triggered by IL-6 treatment.Mechanistically,IGF2BP2 was bound to CTNNB1 transcripts,significantly enhancing their stability and translation,and conferring stem-like properties.Finally,we confirmed that the combination of m6A writers,IGF2BP2,and CTNNB1 distinguished CCA tissues from normal tissues.Conclusions:Overall,this study showed that the IL-6-triggered inflammatory response facilitated the expressions of m6A writers and cell stemness in an m6A-IGF2BP2-dependent manner.Furthermore,the study showed that m6A modification was a targetable mediator of the response to inflammation factor exposure,was a potential diagnostic biomarker for CCA,and was critical to the progression of CCA.