1 5531 71 RNAI THERAPEUTICS: AN ANTIVIRAL STRATEGY FOR HUMAN INFECTIONS. GENE SILENCING INDUCED BY RNAI REPRESENTS A PROMISING ANTIVIRAL DEVELOPMENT STRATEGY. THIS REVIEW WILL SUMMARISE THE CURRENT STATE OF RNAI THERAPEUTICS FOR TREATING ACUTE AND CHRONIC HUMAN VIRUS INFECTIONS. THE GENE SILENCING PATHWAYS EXPLOITED BY RNAI THERAPEUTICS WILL BE DESCRIBED AND INCLUDE BOTH CLASSIC RNAI, INDUCING CYTOPLASMIC MRNA DEGRADATION POST-TRANSCRIPTION AND NOVEL RNAI, MEDIATING EPIGENETIC MODIFICATIONS AT THE TRANSCRIPTION LEVEL IN THE NUCLEUS. FINALLY, THE CHALLENGE OF DELIVERING GENE MODIFICATIONS VIA RNAI WILL BE DISCUSSED, ALONG WITH THE UNIQUE CHARACTERISTICS OF RESPIRATORY VERSUS SYSTEMIC ADMINISTRATION ROUTES TO HIGHLIGHT RECENT ADVANCES AND FUTURE POTENTIAL OF RNAI ANTIVIRAL TREATMENT STRATEGIES. 2020 2 947 22 CHRONIC MEHG EXPOSURE MODIFIES THE HISTONE H3K4ME3 EPIGENETIC LANDSCAPE IN CAENORHABDITIS ELEGANS. METHYLMERCURY (MEHG) IS A PERSISTENT ENVIRONMENTAL POLLUTANT THAT OCCURS IN THE FOOD CHAIN, AT OCCUPATIONAL SITES, AND VIA MEDICAL PROCEDURES. EXPOSURE IN HUMANS AND ANIMAL MODELS RESULTS IN RENAL, NEURO, AND REPRODUCTIVE TOXICITIES. IN THIS STUDY, WE DEMONSTRATE THAT CHRONIC EXPOSURE TO MEHG (10MUM) CAUSES EPIGENETIC LANDSCAPE MODIFICATIONS OF HISTONE H3K4 TRIMETHYLATION (H3K4ME3) MARKS IN CAENORHABDITIS ELEGANS USING CHROMATIN IMMUNO-PRECIPITATION SEQUENCING (CHIP-SEQ). THE MODIFICATIONS CORRESPOND TO THE LOCATIONS OF 1467 GENES WITH ENHANCED AND 508 GENES WITH REDUCED SIGNALS. AMONG ENHANCED GENES ARE THOSE ENCODING GLUTATHIONE-S-TRANSFERASES, LIPOCALIN-RELATED PROTEIN AND A CUTICULAR COLLAGEN. CHIP-SEQ ENHANCEMENT OF THESE GENES WAS CONFIRMED WITH INCREASED MRNA EXPRESSION LEVELS REVEALED BY QRT-PCR. FURTHERMORE, WE OBSERVED ENHANCEMENT OF H3K4ME3 MARKS IN THESE GENES IN ANIMALS EXPOSED TO MEHG IN UTERO AND ASSAYED AT L4 STAGE. IN UTERO EXPOSURE ENHANCED MARKS WITHOUT ALTERATIONS IN MRNA EXPRESSION EXCEPT FOR THE LPR-5 GENE. FINALLY, KNOCKDOWN OF LIPOCALIN-RELATED PROTEIN GENE LPR-5, WHICH IS INVOLVED IN INTERCELLULAR SIGNALING, AND CUTICULAR COLLAGEN GENE DPY-7, STRUCTURAL COMPONENT OF THE CUTICLE, BY RNA INTERFERENCE (RNAI) RESULTED IN INCREASED LETHALITY OF ANIMALS AFTER MEHG EXPOSURE. OUR RESULTS PROVIDE NEW DATA ON THE EPIGENETIC LANDSCAPE CHANGES ELICITED BY MEHG EXPOSURE, AS WELL AS DESCRIBE A UNIQUE MODEL FOR STUDYING IN UTERO EFFECTS OF HEAVY METALS. TOGETHER, THESE FINDINGS MAY HELP TO UNDERSTAND THE TOXICOLOGICAL EFFECTS OF MEHG AT THE MOLECULAR LEVEL. 2017 3 4593 17 NATURAL GENETIC VARIATION IN A MULTIGENERATIONAL PHENOTYPE IN C. ELEGANS. ALTHOUGH HEREDITY MOSTLY RELIES ON THE TRANSMISSION OF DNA SEQUENCE, ADDITIONAL MOLECULAR AND CELLULAR FEATURES ARE HERITABLE ACROSS SEVERAL GENERATIONS. IN THE NEMATODE CAENORHABDITIS ELEGANS, INSIGHTS INTO SUCH UNCONVENTIONAL INHERITANCE RESULT FROM TWO LINES OF WORK. FIRST, THE MORTAL GERMLINE (MRT) PHENOTYPE WAS DEFINED AS A MULTIGENERATIONAL PHENOTYPE WHEREBY A SELFING LINEAGE BECOMES STERILE AFTER SEVERAL GENERATIONS, IMPLYING MULTIGENERATIONAL MEMORY [1, 2]. SECOND, CERTAIN RNAI EFFECTS ARE HERITABLE OVER SEVERAL GENERATIONS IN THE ABSENCE OF THE INITIAL TRIGGER [3-5]. BOTH LINES OF WORK CONVERGED WHEN THE SUBSET OF MRT MUTANTS THAT ARE HEAT SENSITIVE WERE FOUND TO CLOSELY CORRESPOND TO MUTANTS DEFECTIVE IN THE RNAI-INHERITANCE MACHINERY, INCLUDING HISTONE MODIFIERS [6-9]. HERE, WE REPORT THE SURPRISING FINDING THAT SEVERAL C. ELEGANS WILD ISOLATES DISPLAY A HEAT-SENSITIVE MORTAL GERMLINE PHENOTYPE IN LABORATORY CONDITIONS: UPON CHRONIC EXPOSURE TO HIGHER TEMPERATURES, SUCH AS 25 DEGREES C, LINES REPRODUCIBLY BECOME STERILE AFTER SEVERAL GENERATIONS. THIS PHENOMENON IS REVERSIBLE, AS IT CAN BE SUPPRESSED BY TEMPERATURE ALTERNATIONS AT EACH GENERATION, SUGGESTING A NON-GENETIC BASIS FOR THE STERILITY. WE TESTED WHETHER NATURAL VARIATION IN THE TEMPERATURE-INDUCED MRT PHENOTYPE WAS OF GENETIC NATURE BY BUILDING RECOMBINANT INBRED LINES BETWEEN THE ISOLATES MY10 (MRT) AND JU1395 (NON-MRT). USING BULK SEGREGANT ANALYSIS, WE DETECTED TWO QUANTITATIVE TRAIT LOCI. AFTER FURTHER RECOMBINANT MAPPING AND GENOME EDITING, WE IDENTIFIED THE MAJOR CAUSAL LOCUS AS A POLYMORPHISM IN THE SET-24 GENE, ENCODING A SET- AND SPK-DOMAIN PROTEIN. WE CONCLUDE THAT C. ELEGANS NATURAL POPULATIONS MAY HARBOR NATURAL GENETIC VARIATION IN EPIGENETIC INHERITANCE PHENOMENA. 2018 4 4308 15 MICRORNA?155 MODULATION OF CD8(+) T?CELL ACTIVITY PERSONALIZES RESPONSE TO DISEASE?MODIFYING THERAPIES OF PATIENTS WITH RELAPSING?REMITTING MULTIPLE SCLEROSIS. MULTIPLE SCLEROSIS (MS) IS A CHRONIC AUTOIMMUNE DISEASE WHERE ACTIVATED IMMUNE CELLS CAN ATTACK OLIGODENDROCYTES CAUSING DAMAGE TO THE MYELIN SHEATH. SEVERAL MOLECULAR MECHANISMS ARE RESPONSIBLE FOR THE AUTO-ACTIVATION OF IMMUNE CELLS SUCH AS RNA INTERFERENCE (RNAI) THROUGH MICRORNAS (MIRNAS OR MIRS). IN THE PRESENT STUDY, THE ROLE OF MIR-155 IN REGULATING CD8(+) T-CELL ACTIVITY IN PATIENTS WITH RELAPSING-REMITTING MULTIPLE SCLEROSIS (RRMS) WAS INVESTIGATED, IN TERMS OF ITS MIGRATORY FUNCTIONS WITH REGARD TO INTRACELLULAR ADHESION MOLECULE-1 (ICAM1) AND INTEGRIN SUBUNIT BETA2 (ITGB2), AND ITS CYTOTOXIC PROTEINS, PERFORIN AND GRANZYME B. GENE EXPRESSION OF MIR-155, ICAM1, ITGB2, PERFORIN AND GRANZYME B WAS EVALUATED FOLLOWING EPIGENETIC MODULATIONS USING REVERSE TRANSCRIPTION-QUANTITATIVE POLYMERASE CHAIN REACTION IN CD8(+) T-CELLS ISOLATED FROM BLOOD SAMPLES OF PATIENTS WITH RRMS AND COMPARED TO HEALTHY CONTROLS. THE ECTOPIC EXPRESSION OF MIR-155 RESULTED IN A PERSISTENT DOWNREGULATION IN ALL GENES OF INTEREST RELATED TO CD8(+) T-CELL ACTIVATION THAT WERE POSITIVELY CORRELATED WITH THE EXPANDED DISABILITY STATUS SCALE OF PATIENTS. THE PRESENT STUDY REVEALED THE INTERPLAY BETWEEN MIR-155, ICAM1, AND ITGB2, SHEDDING LIGHT ON THEIR BENEFICIAL USE AS POSSIBLE THERAPEUTIC REGULATORS AND DIAGNOSTIC BIOMARKERS OF DISEASE. MOREOVER, EPIGENETIC MODULATIONS ENHANCING THE EFFICACY OF DISEASE-MODIFYING THERAPIES (DMTS) MAY BE EMPLOYED AS PERSONALIZED THERAPY, TO DECREASE THE SIDE EFFECTS OF DMTS AND IMPROVE THE OUTCOMES OF PATIENTS. 2023 5 6434 21 THE VON HIPPEL LINDAU TUMOUR SUPPRESSOR GENE IS A NOVEL TARGET OF E2F4-MEDIATED TRANSCRIPTIONAL REPRESSION IN PREECLAMPSIA. THE VON HIPPEL LINDAU TUMOUR SUPPRESSOR (VHL) PROTEIN IS ESSENTIAL FOR PROPER PLACENTAL DEVELOPMENT AND IS DOWNREGULATED IN PREECLAMPSIA (PE), A DEVASTATING DISORDER OF PREGNANCY TYPIFIED BY CHRONIC HYPOXIA. TO DATE, KNOWLEDGE ON VHL GENETIC AND EPIGENETIC REGULATION IS RESTRICTED TO INACTIVATING MUTATIONS AND LOSS-OF-HETEROZYGOSITY IN RENAL CELL CARCINOMAS. HEREIN, WE SOUGHT TO EXAMINE WHETHER VHL DNA IS SUBJECT TO DIFFERENTIAL METHYLATION, AND IF SO, WHETHER IT IS ALTERED IN EARLY-ONSET PE (E-PE). SODIUM BISULFITE MODIFICATION AND METHYLATION-SPECIFIC PCR ANALYSIS REVEALED THAT VHL IS SUBJECT TO EXTENSIVE METHYLATION IN A CPG-RICH REGION WITHIN ITS PROMOTER IN THE HUMAN PLACENTA. NOTABLY, WE DETECTED SIGNIFICANT DIFFERENCES IN METHYLATION IN E-PE PLACENTAE RELATIVE TO NORMOTENSIVE AGE-MATCHED CONTROLS AT KEY TRANSCRIPTION FACTOR BINDING SITES, INCLUDING THAT OF THE TRANSCRIPTIONAL REPRESSOR E2F4. TREATMENT OF JEG3 CELLS WITH 5-AZA-2'-DEOXYCYTIDINE, REVEALED THAT LOSS OF DNA METHYLATION PROMOTED VHL TRANSCRIPTION BY ATTENUATING VHL ASSOCIATION WITH E2F4. RNAI KNOCKDOWN OF E2F4 IN VITRO CONFIRMED ITS FUNCTION ON VHL REPRESSION. EXPOSURE OF JEG3 CELLS TO TRANSFORMING GROWTH FACTOR BETA (TGFBETA) DOWNREGULATED VHL MRNA. IN LINE WITH ELEVATED LEVELS OF TGFBETA3 IN E-PE, CHROMATIN IMMUNOPRECIPITATION ASSAYS REVEALED THAT E2F4-VHL ASSOCIATION WAS ENHANCED UPON TGFBETA3 TREATMENT, INDICATIVE OF VHL TRANSCRIPTIONAL INHIBITION. IN LINE WITH DECREASED VHL EXPRESSION IN E-PE, AUGMENTED E2F4-VHL ASSOCIATION WAS ALSO OBSERVED IN E-PE PLACENTAL TISSUE RELATIVE TO CONTROLS. IN CONCLUSION, WE DEMONSTRATE FOR THE FIRST TIME THAT HYPOMETHYLATION OF VHL DNA AT A KEY TRANSCRIPTION FACTOR BINDING SITE HAS SIGNIFICANT CONSEQUENCES FOR ITS TRANSCRIPTIONAL REPRESSION IN EARLY-ONSET PREECLAMPSIA. 2018 6 2529 17 EPIGENETICS CHANGES ASSOCIATED TO ENVIRONMENTAL TRIGGERS IN AUTOIMMUNITY. AUTOIMMUNE DISEASES (AIDS) ARE CHRONIC CONDITIONS INITIATED BY THE LOSS OF IMMUNOLOGICAL TOLERANCE TO SELF-ANTIGENS AND REPRESENT A HETEROGENEOUS GROUP OF DISORDERS THAT AFFECT SPECIFIC TARGET ORGANS OR MULTIPLE ORGANS IN DIFFERENT SYSTEMS. WHILE THE PATHOGENESIS OF AID REMAINS UNCLEAR, ITS AETIOLOGY IS MULTIFUNCTIONAL AND INCLUDES A COMBINATION OF GENETIC, EPIGENETIC, IMMUNOLOGICAL AND ENVIRONMENTAL FACTORS. IN AIDS, SEVERAL EPIGENETIC MECHANISMS ARE DEFECTIVE INCLUDING DNA DEMETHYLATION, ABNORMAL CHROMATIN POSITIONING ASSOCIATED WITH AUTOANTIBODY PRODUCTION AND ABNORMALITIES IN THE EXPRESSION OF RNA INTERFERENCE (RNAI). IT IS KNOWN THAT ENVIRONMENTAL FACTORS MAY INTERFERE WITH DNA METHYLATION AND HISTONE MODIFICATIONS, HOWEVER, LITTLE IS KNOWN ABOUT EPIGENETIC CHANGES DERIVED OF REGULATION OF RNAI. AN APPROACH TO THE KNOWN ENVIRONMENTAL FACTORS AND THE MECHANISMS THAT ALTER THE EPIGENETIC REGULATION IN AIDS (WITH EMPHASIS IN SYSTEMIC LUPUS ERYTHEMATOSUS, THE PROTOTYPE OF SYSTEMIC AID) ARE SHOWED IN THIS REVIEW. 2016 7 2748 15 EXPRESSION AND FUNCTION OF EZH2 IN SYNOVIAL FIBROBLASTS: EPIGENETIC REPRESSION OF THE WNT INHIBITOR SFRP1 IN RHEUMATOID ARTHRITIS. OBJECTIVES: TO STUDY THE EXPRESSION, REGULATION AND FUNCTION OF THE HISTONE METHYLTRANSFERASE ENHANCER OF ZESTE HOMOLOGUE 2 (EZH2) IN SYNOVIAL FIBROBLASTS (SF) FROM PATIENTS WITH RHEUMATOID ARTHRITIS (RA) AND OSTEOARTHRITIS (OA). METHODS: SF WERE OBTAINED FROM RA AND OA PATIENTS UNDERGOING JOINT SURGERY. EXPRESSION LEVELS WERE ASSESSED BY QUANTITATIVE REAL-TIME PCR AND WESTERN BLOT. KINASE INHIBITORS AND REPORTER GENE ASSAYS WERE EMPLOYED TO STUDY SIGNALLING PATHWAYS. FUNCTIONAL ANALYSES INCLUDED EZH2 OVEREXPRESSION BY PLASMID TRANSFECTION AND GENE SILENCING BY SMALL INTERFERING RNA. CHROMATIN IMMUNOPRECIPITATION ASSAY WAS USED TO ANALYSE HISTONE METHYLATION WITHIN DISTINCT PROMOTER REGIONS. RESULTS: BY STUDYING THE EXPRESSION AND FUNCTION OF EZH2 IN SF THE AUTHORS FOUND THAT EZH2 IS OVEREXPRESSED IN RHEUMATOID ARTHRITIS SYNOVIAL FIBROBLASTS (RASF) AND FURTHER INDUCED BY TUMOUR NECROSIS FACTOR ALPHA THROUGH THE NUCLEAR FACTOR KAPPA B AND JUN KINASE PATHWAYS. AS A TARGET GENE OF EZH2 THE AUTHORS IDENTIFIED SECRETED FRIZZLED-RELATED PROTEIN 1 (SFRP1), AN INHIBITOR OF WNT SIGNALLING, WHICH IS ASSOCIATED WITH THE ACTIVATION OF RASF, AND SHOW THAT SFRP1 EXPRESSION CORRELATES WITH THE OCCUPATION OF ITS PROMOTER WITH ACTIVATING AND SILENCING HISTONE MARKS. CONCLUSIONS: THESE DATA STRONGLY SUGGEST THAT THE CHRONIC INFLAMMATORY ENVIRONMENT OF THE RA JOINT INDUCES EZH2 AND THUS MIGHT CAUSE CHANGES IN THE EPIGENETIC PROGRAMMES OF SF. 2011 8 45 17 A COMPREHENSIVE REVIEW ON RNA INTERFERENCE-MEDIATED TARGETING OF INTERLEUKINS AND ITS POTENTIAL THERAPEUTIC IMPLICATIONS IN COLON CANCER. COLON CANCER IS THE WORLD'S FOURTH LEADING CAUSE OF DEATH. IT IS CANCER OF THE LATTER PART OF THE LARGE INTESTINE, I.E. THE COLON. CHRONIC INFLAMMATION OVER A LONG PERIOD ALSO LEADS TO THE DEVELOPMENT OF CANCER. CANCER IN THE COLON REGION IS ARDUOUS TO DIAGNOSE AND IS DETECTED AT A LATER STAGE WHEN IT METASTASIZES TO OTHER PARTS OF THE BODY LIKE THE LIVER, LUNGS, PERITONEUM, ETC. COLON CANCER IS A GREAT EXAMPLE OF SOLID TUMOURS ASSOCIATED WITH CHRONIC INFLAMMATION. ALTHOUGH CONVENTIONAL THERAPIES ARE EFFECTIVE, THEY LOSE THEIR EFFECTIVENESS BEYOND A CERTAIN POINT. RELAPSE OF THE DISEASE OCCURS FREQUENTLY. RNA INTERFERENCE (RNAI) IS EMERGING AS A GREAT TOOL TO SPECIFICALLY ATTACK THE CANCER CELLS OF A TARGET SITE LIKE THE COLON. RNAI DEALS WITH EPIGENETIC CHANGES MADE IN THE DEFECTIVE CELLS WHICH ULTIMATELY LEADS TO THEIR DEATH WITHOUT HARMING THE HEALTHY CELLS. IN THIS REVIEW, TWO TYPES OF EPIGENETIC MODULATORS HAVE BEEN CONSIDERED, NAMELY SIRNA AND MIRNA, AND THEIR EFFECT ON INTERLEUKINS. INTERLEUKINS, A CLASS OF CYTOKINES, ARE MAJOR INFLAMMATORY RESPONSES OF THE BODY THAT ARE RELEASED BY IMMUNE CELLS LIKE LEUKOCYTES AND MACROPHAGES. SOME OF THESE INTERLEUKINS ARE PRO-INFLAMMATORY, THEREBY PROMOTING INFLAMMATION WHICH EVENTUALLY CAUSES CANCER. RNAI CAN PREVENT COLON CANCER BY INHIBITING PRO-INFLAMMATORY INTERLEUKINS. 2023 9 6235 17 THE M(6)A DEMETHYLASE FTO PROMOTES RENAL EPITHELIAL-MESENCHYMAL TRANSITION BY REDUCING THE M(6)A MODIFICATION OF LNCRNA GAS5. BACKGROUND: RENAL INTERSTITIAL FIBROSIS (RIF) IS THE MAIN PATHOLOGICAL CHANGE OF A VARIETY OF CHRONIC KIDNEY DISEASES (CKD). EPIGENETIC MODIFICATIONS OF FIBROSIS-PRONE GENES REGULATE RIF PROGRESSION. THIS STUDY AIMED TO INVESTIGATE LONG NON-CODING RNA (LNCRNA) N6-METHYLADENOSINE (M(6)A) MODIFICATION AND ITS ROLE IN REGULATING RIF PROGRESSION. METHODS: UNILATERAL URETERAL OCCLUSION (UUO) WAS EMPLOYED TO CONSTRUCT THE RIF IN VIVO MODEL; AND TGF-BETA1-TREATED HK-2 AND HKC-8 CELLS WERE USED FOR IN VITRO EXPERIMENTS. THE MRNA AND PROTEIN EXPRESSIONS WERE ASSESSED USING QRT-PCR AND WESTERN BLOT. THE PROLIFERATION AND MIGRATION WERE EVALUATED BY EDU ASSAY AND TRANSWELL ASSAY, RESPECTIVELY. IN ADDITION, LEVELS OF INFLAMMATORY CYTOKINES WERE DETERMINED BY ELISA ASSAY AND QRT-PCR. MOREOVER, LNCRNA GAS5 M(6)A LEVEL WAS DETECTED USING ME-RIP ASSAY. HE AND MASSON STAINING WERE EMPLOYED TO EVALUATE FIBROTIC LESIONS OF THE KIDNEY. RESULTS: FTO EXPRESSION WAS ELEVATED IN HK-2 AND HKC-8 CELLS AFTER TGF-BETA1 TREATMENT AND MOUSE KIDNEY TISSUE FOLLOWING UUO, AND LNCRNA GAS5 WAS DOWNREGULATED. LNCRNA GAS5 OVEREXPRESSION OR FTO SILENCING SUPPRESSED TGF-BETA1-INDUCED THE INCREASE OF EMT-RELATED PROTEINS (VIMENTIN, SNAIL AND N-CADHERIN) AND INFLAMMATORY CYTOKINES (IL-6, IL-1BETA AND TNF-ALPHA) LEVELS IN HK-2 CELLS. FTO SUPPRESSED LNCRNA GAS5 EXPRESSION BY REDUCING THE M6A MODIFICATION OF LNCRNA GAS5. ADDITIONALLY, FTO KNOCKDOWN COULD SUPPRESS EMT PROCESS AND INFLAMMATION RESPONSE INDUCED BY TGF-BETA1 AND UUO IN VITRO AND IN VIVO. AS EXPECTED, FTO KNOCKDOWN ABROGATED THE PROMOTION EFFECTS OF LNCRNA GAS5 SILENCING ON TGF-BETA1-INDUCED EMT PROCESS AND INFLAMMATION RESPONSE IN HK-2 AND HKC-8 CELLS. CONCLUSION: FTO PROMOTED EMT PROCESS AND INFLAMMATION RESPONSE THROUGH REDUCING THE M(6)A MODIFICATION OF LNCRNA GAS5. 2022 10 5715 24 SIRT3 RESTRICTS HEPATITIS B VIRUS TRANSCRIPTION AND REPLICATION THROUGH EPIGENETIC REGULATION OF COVALENTLY CLOSED CIRCULAR DNA INVOLVING SUPPRESSOR OF VARIEGATION 3-9 HOMOLOG 1 AND SET DOMAIN CONTAINING 1A HISTONE METHYLTRANSFERASES. HEPATITIS B VIRUS (HBV) INFECTION REMAINS A MAJOR HEALTH PROBLEM WORLDWIDE. MAINTENANCE OF THE COVALENTLY CLOSED CIRCULAR DNA (CCCDNA), WHICH SERVES AS A TEMPLATE FOR HBV RNA TRANSCRIPTION, IS RESPONSIBLE FOR THE FAILURE OF ERADICATING CHRONIC HBV DURING CURRENT ANTIVIRAL THERAPY. CCCDNA IS ASSEMBLED WITH CELLULAR HISTONE PROTEINS INTO CHROMATIN, BUT LITTLE IS KNOWN ABOUT THE REGULATION OF HBV CHROMATIN BY HISTONE POSTTRANSLATIONAL MODIFICATIONS. IN THIS STUDY, WE IDENTIFIED SILENT MATING TYPE INFORMATION REGULATION 2 HOMOLOG 3 (SIRT3) AS A HOST FACTOR RESTRICTING HBV TRANSCRIPTION AND REPLICATION BY SCREENING SEVEN MEMBERS OF THE SIRTUIN FAMILY, WHICH IS THE CLASS III HISTONE DEACETYLASE. ECTOPIC SIRT3 EXPRESSION SIGNIFICANTLY REDUCED TOTAL HBV RNAS, 3.5-KB RNA, AS WELL AS REPLICATIVE INTERMEDIATE DNA IN HBV-INFECTED HEPG2-NA(+) /TAUROCHOLATE COTRANSPORTING POLYPEPTIDE CELLS AND PRIMARY HUMAN HEPATOCYTES. IN CONTRAST, GENE SILENCING OF SIRT3 PROMOTED HBV TRANSCRIPTION AND REPLICATION. A MECHANISTIC STUDY FOUND THAT NUCLEAR SIRT3 WAS RECRUITED TO THE HBV CCCDNA, WHERE IT DEACETYLATED HISTONE 3 LYSINE 9. IMPORTANTLY, OCCUPANCY OF SIRT3 ON CCCDNA COULD INCREASE THE RECRUITMENT OF HISTONE METHYLTRANSFERASE SUPPRESSOR OF VARIEGATION 3-9 HOMOLOG 1 TO CCCDNA AND DECREASE RECRUITMENT OF SET DOMAIN CONTAINING 1A, LEADING TO A MARKED INCREASE OF TRIMETHYL-HISTONE H3 (LYS9) AND A DECREASE OF TRIMETHYL-HISTONE H3 (LYS4) ON CCCDNA. MOREOVER, SIRT3-MEDIATED HBV CCCDNA TRANSCRIPTIONAL REPRESSION INVOLVED DECREASED BINDING OF HOST RNA POLYMERASE II AND TRANSCRIPTION FACTOR YIN YANG 1 TO CCCDNA. FINALLY, HEPATITIS B VIRAL X PROTEIN COULD RELIEVE SIRT3-MEDIATED CCCDNA TRANSCRIPTIONAL REPRESSION BY INHIBITING BOTH SIRT3 EXPRESSION AND ITS RECRUITMENT TO CCCDNA. CONCLUSION: SIRT3 IS A HOST FACTOR EPIGENETICALLY RESTRICTING HBV CCCDNA TRANSCRIPTION BY ACTING COOPERATIVELY WITH HISTONE METHYLTRANSFERASE; THESE DATA PROVIDE A RATIONALE FOR THE USE OF SIRT3 ACTIVATORS IN THE PREVENTION OR TREATMENT OF HBV INFECTION. (HEPATOLOGY 2018). 2018 11 3246 15 HEPATITIS B VIRUS (HBV) INDUCES THE EXPRESSION OF INTERLEUKIN-8 THAT IN TURN REDUCES HBV SENSITIVITY TO INTERFERON-ALPHA. HIGH LEVELS OF SERUM INTERLEUKIN-8 (IL-8) HAVE BEEN DETECTED IN CHRONIC HEPATITIS B (CHB) PATIENTS DURING EPISODES OF HEPATITIS FLARES. WE INVESTIGATED WHETHER HEPATITIS B VIRUS (HBV) MAY DIRECTLY INDUCE IL-8 PRODUCTION AND WHETHER IL-8 MAY ANTAGONIZE INTERFERON-ALPHA (IFN-ALPHA) ANTIVIRAL ACTIVITY AGAINST HBV. WE SHOWED THAT CHB PATIENTS HAD SIGNIFICANTLY HIGHER IL-8 LEVELS BOTH IN SERUM AND IN LIVER TISSUE THAN CONTROLS. IN HBV-REPLICATING HEPG2 CELLS, IL-8 TRANSCRIPTION WAS SIGNIFICANTLY ACTIVATED. AP-1, C/EBP AND NF-KB TRANSCRIPTION FACTORS WERE CONCURRENTLY NECESSARY FOR MAXIMUM IL-8 INDUCTION. MOREOVER, HBX VIRAL PROTEIN WAS RECRUITED ONTO THE IL-8 PROMOTER AND THIS WAS PARALLELED BY IL8-BOUND HISTONE HYPERACETYLATION AND BY ACTIVE RECRUITMENT OF TRANSCRIPTIONAL COACTIVATORS. INHIBITION OF IL-8 INCREASES THE ANTIVIRAL ACTIVITY OF IFN-ALPHA AGAINST HBV. OUR RESULTS INDICATE THAT HBV ACTIVATES IL-8 GENE EXPRESSION BY TARGETING THE EPIGENETIC REGULATION OF THE IL-8 PROMOTER AND THAT IL-8 MAY CONTRIBUTE TO REDUCE HBV SENSITIVITY TO IFN-ALPHA. 2013 12 4239 21 METHYLATION PROFILE OF HEPATITIS B VIRUS IS NOT INFLUENCED BY INTERFERON ALPHA IN HUMAN LIVER CANCER CELLS. INTERFERON (IFN) ALPHA IS USED FOR THE TREATMENT OF CHRONIC HEPATITIS B VIRUS (HBV) INFECTION, BUT THE MOLECULAR MECHANISMS UNDERLYING ITS ANTIVIRAL EFFECT HAVE NOT BEEN FULLY ELUCIDATED. EPIGENETIC MODIFICATIONS REGULATE THE TRANSCRIPTIONAL ACTIVITY OF COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) IN CELLS WITH CHRONIC HBV INFECTION. IFN?ALPHA HAS BEEN SHOWN TO MODIFY CCCDNA?BOUND HISTONES, BUT IT IS NOT KNOWN WHETHER THE ANTI?HBV EFFECT OF IFN?ALPHA INVOLVES METHYLATION OF CCCDNA. THE PRESENT STUDY AIMED TO DETERMINE WHETHER IFN?ALPHA INDUCED METHYLATION OF HBV CCCDNA IN A CELL?BASED MODEL IN WHICH HEPG2 CELLS WERE DIRECTLY INFECTED WITH WILD?TYPE HBV VIRIONS. METHYLATION STATUS OF HBV CCCDNA WAS ASSESSED USING GLOBAL DNA METHYLATION ELISA ASSAY, METHYLATION?SPECIFIC PCR AND BISULFITE SEQUENCING. IFN?ALPHA SUPPRESSED HBV DNA AND RNA TRANSCRIPTS, BUT METHYLATION PROFILES WERE SIMILAR BETWEEN THE CONTROL AND IFN?ALPHA TREATED GROUPS. CHROMATIN IMMUNOPRECIPITATION RESULTS REVEALED BINDING OF DNA METHYLTRANSFERASES (DNMT) 3A AND DNMT3B TO HBV CCCDNA AND TREATMENT WITH IFN?ALPHA SUPPRESSED THE RECRUITMENT OF DNMT3B TO CCCDNA. TAKEN TOGETHER, THESE RESULTS SUGGEST THAT IFN?ALPHA DOES NOT INDUCE METHYLATION OF HBV CCCDNA. THEREFORE, IT WAS CONCLUDED THAT METHYLATION IS UNLIKELY TO CONTRIBUTE TO THE ANTI?HBV EFFECT OF IFN?ALPHA IN HEPG2 CELLS, AND THAT ALTERNATIVE MECHANISMS NEED TO BE SOUGHT TO ENHANCE CCCDNA METHYLATION AS A NOVEL THERAPY AGAINST HBV. 2021 13 1620 18 DNA METHYLTRANSFERASE-MEDIATED TRANSCRIPTIONAL SILENCING IN MALIGNANT GLIOMA: A COMBINED WHOLE-GENOME MICROARRAY AND PROMOTER ARRAY ANALYSIS. EPIGENETIC INACTIVATION OF TUMOR SUPPRESSOR GENES IS A COMMON FEATURE IN HUMAN CANCER. PROMOTER HYPERMETHYLATION AND HISTONE DEACETYLATION ARE REVERSIBLE EPIGENETIC MECHANISMS ASSOCIATED WITH TRANSCRIPTIONAL REGULATION. DNA METHYLTRANSFERASES (DNMT1 AND DNMT3B) REGULATE AND MAINTAIN PROMOTER METHYLATION AND ARE OVEREXPRESSED IN HUMAN CANCER. WE PERFORMED WHOLE-GENOME MICROARRAY ANALYSIS TO IDENTIFY GENES WITH ALTERED EXPRESSION AFTER RNAI-INDUCED SUPPRESSION OF DNMT IN A GLIOBLASTOMA MULTIFORME (GBM) CELL LINE. WE THEN IDENTIFIED GENES WITH BOTH DECREASED EXPRESSION AND EVIDENCE OF PROMOTER CPG ISLAND HYPERMETHYLATION IN GBM TISSUE SAMPLES USING A COMBINED WHOLE-GENOME MICROARRAY TRANSCRIPTOME ANALYSIS IN CONJUNCTION WITH A PROMOTER ARRAY ANALYSIS AFTER DNA IMMUNOPRECIPITATION WITH ANTI-5-METHYLCYTIDINE. DNMT1 AND 3B KNOCKDOWN RESULTED IN THE RESTORED EXPRESSION OF 308 GENES THAT ALSO CONTAINED PROMOTER REGION HYPERMETHYLATION. OF THESE, 43 WERE ALSO FOUND TO BE DOWNREGULATED IN GBM TISSUE SAMPLES. THREE DOWNREGULATED GENES WITH HYPERMETHYLATED PROMOTERS AND RESTORED EXPRESSION IN RESPONSE TO ACUTE DNMT SUPPRESSION WERE ASSAYED FOR METHYLATION CHANGES USING BISULFITE SEQUENCE ANALYSIS OF THE PROMOTER REGION AFTER CHRONIC DNMT SUPPRESSION. RESTORATION OF GENE EXPRESSION WAS NOT ASSOCIATED WITH CHANGES IN PROMOTER REGION METHYLATION, BUT RATHER WITH CHANGES IN HISTONE METHYLATION AND CHROMATIN CONFORMATION. TWO OF THE IDENTIFIED GENES EXHIBITED GROWTH SUPPRESSIVE ACTIVITY IN IN VITRO ASSAYS. COMBINING TARGETED GENETIC MANIPULATIONS WITH COMPREHENSIVE GENOMIC AND EXPRESSION ANALYSES PROVIDES A POTENTIALLY POWERFUL NEW APPROACH FOR IDENTIFYING EPIGENETICALLY REGULATED GENES IN GBM. 2009 14 3189 21 HBX RELIEVES CHROMATIN-MEDIATED TRANSCRIPTIONAL REPRESSION OF HEPATITIS B VIRAL CCCDNA INVOLVING SETDB1 HISTONE METHYLTRANSFERASE. BACKGROUND & AIMS: MAINTENANCE OF THE COVALENTLY CLOSED CIRCULAR HBV DNA (CCCDNA) THAT SERVES AS A TEMPLATE FOR HBV TRANSCRIPTION IS RESPONSIBLE FOR THE FAILURE OF ANTIVIRAL THERAPIES. WHILE STUDIES IN CHRONIC HEPATITIS PATIENTS HAVE SHOWN THAT HIGH VIREMIA CORRELATES WITH HYPERACETYLATION OF CCCDNA-ASSOCIATED HISTONES, THE MOLECULAR MECHANISMS CONTROLLING CCCDNA STABILITY AND TRANSCRIPTIONAL REGULATION ARE STILL POORLY UNDERSTOOD. THIS STUDY AIMED TO DECIPHER THE ROLE OF CHROMATIN AND CHROMATIN MODIFIER PROTEINS ON HBV TRANSCRIPTION. METHODS: WE ANALYZED THE CHROMATIN STRUCTURE OF ACTIVELY TRANSCRIBED OR SILENCED CCCDNA BY INFECTING PRIMARY HUMAN HEPATOCYTES AND DIFFERENTIATED HEPARG CELLS WITH WILD-TYPE VIRUS OR VIRUS DEFICIENT (HBVX-) FOR THE EXPRESSION OF HEPATITIS B VIRUS X PROTEIN (HBX), THAT IS REQUIRED FOR HBV EXPRESSION. RESULTS: IN THE ABSENCE OF HBX, HBV CCCDNA WAS TRANSCRIPTIONALLY SILENCED WITH THE CONCOMITANT DECREASE OF HISTONE 3 (H3) ACETYLATION AND H3K4ME3, INCREASE OF H3 DI- AND TRI-METHYLATION (H3K9ME) AND THE RECRUITMENT OF HETEROCHROMATIN PROTEIN 1 FACTORS (HP1) THAT CORRELATE WITH CONDENSED CHROMATIN. SETDB1 WAS FOUND TO BE THE MAIN HISTONE METHYLTRANSFERASE RESPONSIBLE FOR THE DEPOSITION OF H3K9ME3 AND HBV REPRESSION. FINALLY, FULL TRANSCRIPTIONAL REACTIVATION OF HBVX- UPON HBX RE-EXPRESSION CORRELATED WITH AN INCREASE OF HISTONE ACETYLATION AND H3K4ME3, AND A CONCOMITANT DECREASE OF HP1 BINDING AND OF H3K9ME3 ON THE CCCDNA. CONCLUSION: UPON HBV INFECTION, CELLULAR MECHANISMS INVOLVING SETDB1-MEDIATED H3K9ME3 AND HP1 INDUCE SILENCING OF HBV CCCDNA TRANSCRIPTION THROUGH MODULATION OF CHROMATIN STRUCTURE. HBX IS ABLE TO RELIEVE THIS REPRESSION AND ALLOW THE ESTABLISHMENT OF ACTIVE CHROMATIN. 2015 15 5417 16 REGULATION OF DNA METHYLATION IN RHEUMATOID ARTHRITIS SYNOVIOCYTES. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC INFLAMMATORY DISEASE IN WHICH FIBROBLAST-LIKE SYNOVIOCYTES (FLS) EXHIBIT AN AGGRESSIVE PHENOTYPE. ALTHOUGH THE MECHANISMS RESPONSIBLE ARE NOT WELL DEFINED, EPIGENETIC DETERMINANTS SUCH AS DNA METHYLATION MIGHT CONTRIBUTE. DNA METHYLTRANSFERASES (DNMTS) ARE CRITICAL ENZYMES THAT ESTABLISH AND MAINTAIN DNA METHYLATION. WE EVALUATED WHETHER PROINFLAMMATORY CYTOKINES MIGHT CONTRIBUTE TO DIFFERENTIAL DNA METHYLATION PREVIOUSLY DESCRIBED IN RA FLS THROUGH ALTERED DNMT EXPRESSION. FLS WERE OBTAINED FROM RA AND OSTEOARTHRITIS (OA) SYNOVIUM AT THE TIME OF TOTAL JOINT REPLACEMENT. GENE EXPRESSION WAS DETERMINED BY QUANTITATIVE REAL-TIME PCR AND PROTEIN EXPRESSION BY WESTERN BLOT ANALYSIS. DNMT ACTIVITY WAS MEASURED WITH A FUNCTIONAL ASSAY, AND GLOBAL METHYLATION WAS DETERMINED BY AN IMMUNOASSAY THAT DETECTS METHYLCYTOSINE. RESTING EXPRESSION OF DNMT1, -3A, AND -3B MRNA WERE SIMILAR IN RA AND OA FLS. WESTERN BLOT SHOWED ABUNDANT DNMT1 AND DNMT3A PROTEIN. EXPOSURE TO IL-1 DECREASED DNMT1 AND DNMT3A MRNA EXPRESSION IN FLS. DOSE RESPONSES DEMONSTRATED DECREASED DNMT EXPRESSION AT CONCENTRATIONS AS LOW AS 1 PG/ML OF IL-1. DNMT MRNA LEVELS DECREASED RAPIDLY, WITH SIGNIFICANT SUPPRESSION AFTER 2-8 H OF IL-1 STIMULATION. IL-1 STIMULATION OF OA FLS DID NOT AFFECT METHYLATION OF LINE1 SITES BUT LED TO DEMETHYLATION OF A CHI3L1 LOCUS THAT IS HYPOMETHYLATED IN RA FLS. CHRONIC IL-1 STIMULATION ALSO MIMICKED THE EFFECT OF A DNMT INHIBITOR ON FLS GENE EXPRESSION. EXPOSURE TO PROINFLAMMATORY MEDIATORS REVERSIBLY ALTERS DNA METHYLATION IN FLS BY DECREASING DNMT EXPRESSION AND FUNCTION. THESE DATA SUGGEST THAT IL-1 CAN POTENTIALLY IMPRINT CELLS IN CHRONIC INFLAMMATORY DISEASES. 2013 16 4014 17 LOW-DOSE CD INDUCES HEPATIC GENE HYPERMETHYLATION, ALONG WITH THE PERSISTENT REDUCTION OF CELL DEATH AND INCREASE OF CELL PROLIFERATION IN RATS AND MICE. BACKGROUND: CADMIUM (CD) IS CLASSIFIED AS A HUMAN CARCINOGEN PROBABLY ASSOCIATED WITH EPIGENETIC CHANGES. DNA METHYLATION IS ONE OF EPIGENETIC MECHANISMS BY WHICH CELLS CONTROL GENE EXPRESSION. THEREFORE, THE PRESENT STUDY GENOME-WIDELY SCREENED THE METHYLATION-ALTERED GENES IN THE LIVER OF RATS PREVIOUSLY EXPOSED TO LOW-DOSE CD. METHODOLOGY PRINCIPAL FINDINGS: RATS WERE EXPOSED TO CD AT 20 NMOL/KG EVERY OTHER DAY FOR 4 WEEKS AND GENE METHYLATION WAS ANALYZED AT THE 48(TH) WEEK WITH METHYLATED DNA IMMUNOPRECIPITATION-CPG ISLAND MICROARRAY. AMONG THE 1629 ALTERED GENES, THERE WERE 675 GENES WHOSE PROMOTER CPG ISLANDS (CGIS) WERE HYPERMETHYLATED, 899 GENES WHOSE PROMOTER CGIS WERE HYPOMETHYLATED, AND 55 GENES WHOSE PROMOTER CGIS WERE MIXED WITH HYPER- AND HYPO-METHYLATION. CASPASE-8 GENE PROMOTER CGIS AND TNF GENE PROMOTER CGIS WERE HYPERMETHYLATED AND HYPOMETHYLATED, RESPECTIVELY, ALONG WITH A LOW APOPTOSIS RATE IN CD-TREATED RAT LIVERS. TO LINK THE ABERRANT METHYLATION OF CASPASE-8 AND TNF GENES TO THE LOW APOPTOSIS INDUCED BY LOW-DOSE CD, MICE WERE GIVEN CHRONIC EXPOSURE TO LOW-DOSE CD WITH AND WITHOUT METHYLATION INHIBITOR (5-AZA-2'-DEOXYCTIDENE, 5-AZA). AT THE 48(TH) WEEK AFTER CD EXPOSURE, LIVERS FROM CD-TREATED MICE DISPLAYED THE INCREASED CASPASE-8 CGI METHYLATION AND DECREASED CASPASE-8 PROTEIN EXPRESSION, ALONG WITH SIGNIFICANT INCREASES IN CELL PROLIFERATION AND OVEREXPRESSION OF TGF-BETA1 AND CYTOKERATIN 8/18 (THE LATTER IS A NEW MARKER OF MOUSE LIVER PRENEOPLASTIC LESIONS), ALL WHICH WERE PREVENTED BY 5-AZA TREATMENT. CONCLUSION/SIGNIFICANCE: THESE RESULTS SUGGEST THAT CD-INDUCED GLOBAL GENE HYPERMETHYLATION, MOST LIKELY CASPASE-8 GENE PROMOTER HYPERMETHYLATION THAT DOWN-REGULATED ITS EXPRESSION, LEADING TO THE DECREASED HEPATIC APOPTOSIS AND INCREASED PRENEOPLASTIC LESIONS. 2012 17 1393 15 DIAGNOSTIC VALUE OF THE HYPOMETHYLATION OF THE WISP1 PROMOTER IN PATIENTS WITH HEPATOCELLULAR CARCINOMA ASSOCIATED WITH HEPATITIS B VIRUS. WNT1-INDUCIBLE SIGNALING PATHWAY PROTEIN 1 (WISP1) REGULATES CELL PROLIFERATION, DIFFERENTIATION, ADHESION, MIGRATION AND SURVIVAL. ABNORMAL WISP1 EXPRESSION IS ASSOCIATED WITH THE CARCINOGENESIS OF HEPATOCELLULAR CARCINOMA (HCC). ABERRANT DNA METHYLATION IS ONE OF THE MAJOR EPIGENETIC ALTERATIONS IN HCC. HOWEVER, THE METHYLATION STATUS OF THE WISP1 PROMOTER IS STILL UNCLEAR. WE THEREFORE AIMED TO DETERMINE THE METHYLATION STATUS OF THE WISP1 PROMOTER AND EVALUATE ITS CLINICAL VALUE IN HCC. THE STUDY ENROLLED 251 PARTICIPANTS, INCLUDING 123 PARTICIPANTS WITH HCC, 90 PARTICIPANTS WITH CHRONIC HEPATITIS B (CHB) AND 38 HEALTHY CONTROLS (HCS). WISP1 METHYLATION STATUS, MRNA LEVELS AND PLASMA SOLUBLE WISP1 WERE DETECTED BY METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION (MSP), QUANTITATIVE REAL-TIME PCR (RT-QPCR) AND ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA), RESPECTIVELY. WE FOUND THAT THE METHYLATION FREQUENCY OF WISP1 IN PATIENTS WITH HCC WAS SIGNIFICANTLY LOWER THAN THAT IN PATIENTS WITH CHB AND HCS, WHILE THE RELATIVE EXPRESSION LEVELS OF WISP1 MRNA WERE MARKEDLY HIGHER IN PATIENTS WITH HCC THAN IN PATIENTS WITH CHB AND HCS. FURTHERMORE, THE PLASMA SOLUBLE WISP1 IN PATIENTS WITH HCC WAS OBVIOUSLY LOWER THAN IN THAT IN PATIENTS WITH CHB AND HCS. ALPHA-FETOPROTEIN (AFP) IS A WIDELY RECOGNIZED BIOMARKER TO DIAGNOSE HCC WHICH LACKS ENOUGH SENSITIVITY AND SPECIFICITY. WISP1 PROMOTER METHYLATION STATUS COMBINED WITH AFP SIGNIFICANTLY IMPROVED THE DIAGNOSTIC ABILITY IN DISCRIMINATING HCC FROM CHB COMPARED WITH AFP OR WISP1 METHYLATION STATUS ALONE. IN CONCLUSION, HYPOMETHYLATION OF THE WISP1 GENE PROMOTER MAY SERVE AS A NONINVASIVE BIOMARKER FOR DETECTING HBV-ASSOCIATED HCC. 2020 18 1906 19 ENHANCER OF ZESTE HOMOLOG 2-CATALYSED H3K27 TRIMETHYLATION PLAYS A KEY ROLE IN ACUTE-ON-CHRONIC LIVER FAILURE VIA TNF-MEDIATED PATHWAY. ACUTE-ON-CHRONIC LIVER FAILURE IS MAINLY DUE TO HOST IMMUNITY SELF-DESTRUCTION. THE HISTONE H3 LYSINE 27 (H3K27) TRIMETHYLATING ENZYME, ENHANCER OF ZESTE HOMOLOG 2 (EZH2) MEDIATES EPIGENETIC SILENCING OF GENE EXPRESSION AND REGULATES IMMUNITY, ALSO INVOLVES PATHOGENESIS OF SEVERAL LIVER DISEASES. THE CURRENT STUDY WAS TO DETERMINE THE ROLE OF METHYLTRANSFERASE EZH2 AND ITS CATALYSED H3K27 TRIMETHYLATION (H3K27ME3) IN LIVER FAILURE, AND TO FURTHER INVESTIGATE THE POTENTIAL TARGET FOR LIVER FAILURE TREATMENT. EZH2 AND ITS CATALYSED H3K27ME3 WERE DETERMINED IN PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMC) FROM LIVER FAILURE PATIENTS AND KUPFFER CELLS FROM EXPERIMENTAL MICE. FURTHERMORE, GSK126 (AN INHIBITOR FOR EZH2 TRIMETHYLATION FUNCTION) WAS APPLIED IN LIVER FAILURE MICE IN VIVO, AND LIPOPOLYSACCHARIDE-STIMULATED MONONUCLEAR CELLS IN VITRO. EZH2 AND H3K27ME3 WERE SIGNIFICANTLY UPREGULATED IN HUMAN PBMC FROM LIVER FAILURE PATIENTS OR MURINE KUPFFER CELLS FROM THE LIVER FAILURE ANIMALS, RESPECTIVELY. GSK126 AMELIORATED DISEASE SEVERITY IN LIVER FAILURE MICE, WHICH MAYBE ATTRIBUTE TO DOWN-REGULATE CIRCULATING AND HEPATIC PROINFLAMMATORY CYTOKINES, ESPECIALLY TNF VIA REDUCING H3K27ME3. IN-DEPTH CHROMATIN IMMUNOPRECIPITATION ANALYSIS UNRAVELLED THAT DECREASED ENRICHMENT OF H3K27ME3 ON TNF PROMOTOR, RESULTING IN TNF ELEVATION IN KUPFFER CELLS FROM LIVER FAILURE MICE. NUCLEAR FACTOR KAPPA B (NF-KAPPAB) AND PROTEIN KINASE B (AKT) SIGNALLING PATHWAYS WERE ACTIVATED UPON LIPOPOLYSACCHARIDE STIMULATION, BUT ATTENUATED BY USING GSK126, ACCOMPANIED WITH DECREASED TNF IN VITRO. IN CONCLUSION, EZH2 AND H3K27ME3 CONTRIBUTED TO THE PATHOGENESIS OF LIVER FAILURE VIA TRIGGERING TNF AND OTHER INDISPENSABLE PROINFLAMMATORY CYTOKINES. EZH2 WAS TO MODIFY H3K27ME3 ENRICHMENT, AS WELL AS, ACTIVATION OF THE DOWNSTREAM NF-KAPPAB AND AKT SIGNALLING PATHWAYS. 2018 19 3323 18 HISTONE DEACETYLASE 1 (HDAC1): A KEY PLAYER OF T CELL-MEDIATED ARTHRITIS. RHEUMATOID ARTHRITIS (RA) REPRESENTS A CHRONIC T CELL-MEDIATED INFLAMMATORY AUTOIMMUNE DISEASE. STUDIES HAVE SHOWN THAT EPIGENETIC MECHANISMS CONTRIBUTE TO THE PATHOGENESIS OF RA. HISTONE DEACETYLASES (HDACS) REPRESENT ONE IMPORTANT GROUP OF EPIGENETIC REGULATORS. HOWEVER, THE ROLE OF INDIVIDUAL HDAC MEMBERS FOR THE PATHOGENESIS OF ARTHRITIS IS STILL UNKNOWN. IN THIS STUDY WE DEMONSTRATE THAT MICE WITH A T CELL-SPECIFIC DELETION OF HDAC1 (HDAC1-CKO) ARE RESISTANT TO THE DEVELOPMENT OF COLLAGEN-INDUCED ARTHRITIS (CIA), WHEREAS THE ANTIBODY RESPONSE TO COLLAGEN TYPE II WAS UNDISTURBED, INDICATING AN UNALTERED T CELL-MEDIATED B CELL ACTIVATION. THE INFLAMMATORY CYTOKINES IL-17 AND IL-6 WERE SIGNIFICANTLY DECREASED IN SERA OF HDAC1-CKO MICE. IL-6 TREATED HDAC1-DEFICIENT CD4(+) T CELLS SHOWED AN IMPAIRED UPREGULATION OF CCR6. SELECTIVE INHIBITION OF CLASS I HDACS WITH THE HDAC INHIBITOR MS-275 UNDER TH17-SKEWING CONDITIONS INHIBITED THE UPREGULATION OF CHEMOKINE RECEPTOR 6 (CCR6) IN MOUSE AND HUMAN CD4(+) T CELLS. ACCORDINGLY, ANALYSIS OF HUMAN RNA-SEQUENCING (RNA-SEQ) DATA AND HISTOLOGICAL ANALYSIS OF SYNOVIAL TISSUE SAMPLES FROM HUMAN RA PATIENTS REVEALED THE EXISTENCE OF CD4(+)CCR6(+) CELLS WITH ENHANCED HDAC1 EXPRESSION. OUR DATA INDICATE A KEY ROLE FOR HDAC1 FOR THE PATHOGENESIS OF CIA AND SUGGEST THAT HDAC1 AND OTHER CLASS I HDACS MIGHT BE PROMISING TARGETS OF SELECTIVE HDAC INHIBITORS (HDACI) FOR THE TREATMENT OF RA. 2020 20 6704 16 VHL GENE METHYLATION CONTRIBUTES TO EXCESSIVE ERYTHROCYTOSIS IN CHRONIC MOUNTAIN SICKNESS RAT MODEL BY UPREGULATING THE HIF-2ALPHA/EPO PATHWAY. AIMS: HYPOXIA-INDUCIBLE FACTORS (HIFS) PLAY IMPORTANT ROLES IN THE PATHOGENESIS OF ERYTHROCYTOSIS IN CHRONIC MOUNTAIN SICKNESS (CMS). VON HIPPEL-LINDAU (VHL) IS A KEY REGULATOR OF HYPOXIA THAT CAN DIRECT THE POLY-UBIQUITYLATION AND DEGRADATION OF HIFS. EPIGENETIC MECHANISMS ARE BELIEVED TO CONTRIBUTE TOWARD ADAPTION TO CHRONIC HYPOXIA. HERE, WE INVESTIGATED THE CONTRIBUTION AND MECHANISM OF VHL METHYLATION IN RATS WITH ERYTHROCYTOSIS IN CMS. MAIN METHODS: THE METHYLATION STATUS OF VHL WAS MEASURED VIA BISULFITE SEQUENCING PCR, WHILE VHL, DNMT1, DNMT3ALPHA, AND DNMT3BETA EXPRESSION WERE ASSESSED USING REAL-TIME REVERSE TRANSCRIPTION PCR AND WESTERN BLOTTING. HIF-2ALPHA AND EPO EXPRESSION LEVELS IN BONE MARROW WERE DETERMINED VIA IMMUNOHISTOCHEMICAL STAINING, AND ERYTHROID HYPERPLASIA IN BONE MARROW SECTIONS WERE OBSERVED WITH HEMATOXYLIN AND EOSIN STAINING. KEY FINDINGS: WE FOUND THAT CHRONIC HYPOXIA TRIGGERED ERYTHROID HYPERPLASIA IN THE BONE MARROW AND INCREASED THE QUANTITY OF PERIPHERAL RED BLOOD CELLS IN CMS RATS. CHRONIC HYPOXIA SIGNIFICANTLY INDUCED METHYLATION AT THE CPG SITE IN THE VHL PROMOTER, DECREASED VHL EXPRESSION, AND INCREASED HIF-2ALPHA AND EPO EXPRESSION. CHRONIC HYPOXIA INCREASED DNMT3ALPHA AND DNMT3BETA EXPRESSION, CONSISTENT WITH THE DECREASE IN VHL EXPRESSION. THE DNA METHYLTRANSFERASE INHIBITOR 5-AZACYTIDINE REDUCED CHRONIC HYPOXIA-INDUCED ERYTHROID PROLIFERATION IN THE BONE MARROW OF RATS WITH CMS BY SUPPRESSING VHL METHYLATION AND DNMTS EXPRESSION. SIGNIFICANCE: OUR STUDY SUGGESTS THAT VHL METHYLATION CONTRIBUTES TOWARD EXCESSIVE ERYTHROCYTOSIS IN CMS BY UPREGULATING THE HIF-2ALPHA/EPO PATHWAY IN THE BONE MARROW OF RATS. WE DEMONSTRATED THAT THE DNMT INHIBITOR 5-AZACYTIDINE CAN ATTENUATE ERYTHROID HYPERPLASIA IN THE BONE MARROW BY DEMETHYLATING THE VHL PROMOTER. 2021