1 5510 132 RIBAVIRIN RESTORES IFNALPHA RESPONSIVENESS IN HCV-INFECTED LIVERS BY EPIGENETIC REMODELLING AT INTERFERON STIMULATED GENES. OBJECTIVES: CAVEATS IN THE UNDERSTANDING OF RIBAVIRIN (RBV) MECHANISMS OF ACTION HAS SOMEHOW PREVENTED THE DEVELOPMENT OF BETTER ANALOGUES ABLE TO FURTHER IMPROVE ITS THERAPEUTIC CONTRIBUTION IN INTERFERON (IFN)-BASED AND DIRECT ANTIVIRAL AGENT-BASED REGIMENS FOR CHRONIC HCV OR OTHER INDICATIONS. HERE, WE DESCRIBE A NEW MECHANISM BY WHICH RBV MODULATES IFN-STIMULATED GENES (ISGS) AND CONTRIBUTES TO RESTORE HEPATIC IMMUNE RESPONSIVENESS. DESIGN: RBV EFFECT ON ISG EXPRESSION WAS MONITORED IN VITRO AND IN VIVO, THAT IS, IN NON-TRANSFORMED HEPATOCYTES AND IN THE LIVER OF RBV MONO-TREATED PATIENTS, RESPECTIVELY. MODULATION OF HISTONE MODIFICATIONS AND RECRUITMENT OF HISTONE-MODIFYING ENZYMES AT TARGET PROMOTERS WAS ANALYSED BY CHROMATIN IMMUNOPRECIPITATION IN RBV-TREATED PRIMARY HUMAN HEPATOCYTES AND IN PATIENTS' LIVER BIOPSIES. RESULTS: RBV DECREASES THE MRNA LEVELS OF SEVERAL ABNORMALLY PREACTIVATED ISGS IN PATIENTS WITH HCV, WHO ARE NON-RESPONDERS TO IFN THERAPY. RBV INCREASES G9A HISTONE METHYLTRANSFERASE RECRUITMENT AND HISTONE-H3 LYSINE-9 DIMETHYLATION/TRIMETHYLATION AT SELECTED ISG PROMOTERS IN VITRO AND IN VIVO. G9A PHARMACOLOGICAL BLOCKADE ABOLISHES RBV-INDUCED ISG DOWNREGULATION AND SEVERELY IMPAIRS RBV ABILITY TO POTENTIATE IFN ANTIVIRAL ACTION AND INDUCTION OF ISGS FOLLOWING HCV INFECTION OF PRIMARY HUMAN HEPATOCYTES. CONCLUSIONS: RBV-INDUCED EPIGENETIC CHANGES, LEADING TO DECREASED ISG EXPRESSION, RESTORE AN IFN-RESPONSIVE HEPATIC ENVIRONMENT IN PATIENTS WITH HCV, WHICH MAY ALSO PROVE USEFUL IN IFN-FREE REGIMENS. 2016 2 1991 33 EPIGENETIC ANALYSIS OF THE IFNLAMBDA3 GENE IDENTIFIES A NOVEL MARKER FOR RESPONSE TO THERAPY IN HCV-INFECTED SUBJECTS. CHRONIC HEPATITIS C VIRUS (HCV) INFECTION IS CHARACTERIZED BY HIGH INTERINDIVIDUAL VARIABILITY IN RESPONSE TO PEGYLATED INTERFERON AND RIBAVIRIN. A GENETIC POLYMORPHISM ON CHROMOSOME 19 (RS12979860) UPSTREAM OF INTERFERON-LAMBDA3 (IFNLAMBDA3) IS ASSOCIATED WITH A TWOFOLD CHANGE IN SUSTAINED VIROLOGIC RESPONSE RATE AFTER 48 WEEKS OF TREATMENT WITH PEGYLATED INTERFERON/RIBAVIRIN IN HCV GENOTYPE 1 (GT1) TREATMENT-NAIVE PATIENTS. WE CONDUCTED EPIGENETIC ANALYSIS ON THE IFNLAMBDA3 PROMOTER TO INVESTIGATE WHETHER DNA METHYLATION IS ASSOCIATED WITH RESPONSE TO HCV THERAPY. DNA SAMPLES FROM HCV GT1-INFECTED SUBJECTS RECEIVING AN INTERFERON-FREE PARITAPREVIR-CONTAINING COMBINATION REGIMEN (N=540) AND FROM HCV-UNINFECTED, HEALTHY CONTROLS (N=124) WERE ANALYSED FOR IFNLAMBDA3 METHYLATION LEVELS. METHYLATION WAS STRONGLY ASSOCIATED WITH RS12979860 ALLELE STATUS WHETHER ADJUSTING FOR HCV STATUS (R=65.0%, 95% CI: [60.2%, 69.5%]), OR NOT (R=64.4%), BOTH WITH P<2.2X10(-16) . IN HCV GT1-INFECTED SUBJECTS, C/C GENOTYPES HAD SIGNIFICANTLY LOWER METHYLATION LEVELS RELATIVE TO C/T OR T/T GENOTYPES (P<1X10(-14) ), WITH EACH T ALLELE RESULTING IN A NINE-UNIT INCREASE IN MEAN METHYLATION LEVEL. METHYLATION LEVELS DID NOT CORRELATE WITH RESPONSE IN SUBJECTS TREATED FOR 12 OR 24 WEEKS. HOWEVER, NON-C/C SUBJECTS WITH HIGHER METHYLATION LEVELS WERE MORE LIKELY TO RELAPSE WHEN TREATMENT DURATION WAS 8 WEEKS. THIS ANALYSIS SUGGESTS THAT METHYLATION STATUS OF THE IFNLAMBDA3 PROMOTER REGION MAY BE A USEFUL PARAMETER THAT IDENTIFIES PATIENTS MORE LIKELY TO RELAPSE FOLLOWING HCV THERAPY; HOWEVER, CONTINUING THERAPY FOR A SUFFICIENT DURATION CAN OVERCOME THIS DIFFERENCE. THESE FINDINGS MAY PROVIDE MECHANISTIC INSIGHT INTO THE ROLE OF IFNLAMBDA3 GENETIC VARIANTS IN HCV TREATMENT RESPONSE. 2017 3 3357 36 HISTONE H3 LYSINE 9 DI-METHYLATION AS AN EPIGENETIC SIGNATURE OF THE INTERFERON RESPONSE. EFFECTIVE ANTIVIRAL IMMUNITY DEPENDS ON THE ABILITY OF INFECTED CELLS OR CELLS TRIGGERED WITH VIRUS-DERIVED NUCLEIC ACIDS TO PRODUCE TYPE I INTERFERON (IFN), WHICH ACTIVATES TRANSCRIPTION OF NUMEROUS ANTIVIRAL GENES. HOWEVER, DISPROPORTIONATELY STRONG OR CHRONIC IFN EXPRESSION IS A COMMON CAUSE OF INFLAMMATORY AND AUTOIMMUNE DISEASES. WE DESCRIBE AN EPIGENETIC MECHANISM THAT DETERMINES CELL TYPE-SPECIFIC DIFFERENCES IN IFN AND IFN-STIMULATED GENE (ISG) EXPRESSION IN RESPONSE TO EXOGENOUS SIGNALS. WE IDENTIFY DI-METHYLATION OF HISTONE H3 AT LYSINE 9 (H3K9ME2) AS A SUPPRESSOR OF IFN AND IFN-INDUCIBLE ANTIVIRAL GENE EXPRESSION. WE SHOW THAT LEVELS OF H3K9ME2 AT IFN AND ISG CORRELATE INVERSELY WITH THE SCOPE AND AMPLITUDE OF IFN AND ISG EXPRESSION IN FIBROBLASTS AND DENDRITIC CELLS. ACCORDINGLY, GENETIC ABLATION OR PHARMACOLOGICAL INACTIVATION OF LYSINE METHYLTRANSFERASE G9A, WHICH IS ESSENTIAL FOR THE GENERATION OF H3K9ME2, RESULTED IN PHENOTYPIC CONVERSION OF FIBROBLASTS INTO HIGHLY POTENT IFN-PRODUCING CELLS AND RENDERED THESE CELLS RESISTANT TO PATHOGENIC RNA VIRUSES. IN SUMMARY, OUR STUDIES IMPLICATE H3K9ME2 AND ENZYMES CONTROLLING ITS ABUNDANCE AS KEY REGULATORS OF INNATE ANTIVIRAL IMMUNITY. 2012 4 4239 35 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 5 5715 38 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 6 3264 38 HEPATITIS VIRUS INFECTION AFFECTS DNA METHYLATION IN MICE WITH HUMANIZED LIVERS. BACKGROUND & AIMS: CELLS OF TUMORS ASSOCIATED WITH CHRONIC INFLAMMATION FREQUENTLY HAVE ALTERED PATTERNS OF DNA METHYLATION, INCLUDING HEPATOCELLULAR CARCINOMAS. CHRONIC HEPATITIS HAS ALSO BEEN ASSOCIATED WITH ABERRANT DNA METHYLATION, BUT LITTLE IS KNOWN ABOUT THEIR RELATIONSHIP. METHODS: PYROSEQUENCING WAS USED TO DETERMINE THE METHYLATION STATUS OF CULTURED HUH7.5.1 HEPATOMA CELLS AFTER HEPATITIS C VIRUS (HCV) INFECTION. WE ALSO STUDIED MICE WITH SEVERE COMBINED IMMUNODEFICIENCY CARRYING THE UROKINASE-TYPE PLASMINOGEN ACTIVATOR TRANSGENE CONTROLLED BY AN ALBUMIN PROMOTER (UROKINASE-TYPE PLASMINOGEN ACTIVATOR/SEVERE COMBINED IMMUNODEFICIENT MICE), IN WHICH UP TO 85% OF HEPATOCYTES WERE REPLACED BY HUMAN HEPATOCYTES (CHIMERIC MICE). MICE WERE GIVEN INTRAVENOUS INJECTIONS OF HEPATITIS B VIRUS (HBV) OR HCV, LIVER TISSUES WERE COLLECTED, AND DNA METHYLATION PROFILES WERE DETERMINED AT DIFFERENT TIME POINTS AFTER INFECTION. WE ALSO COMPARED METHYLATION PATTERNS BETWEEN PAIRED SAMPLES OF HEPATOCELLULAR CARCINOMAS AND ADJACENT NONTUMOR LIVER TISSUES FROM PATIENTS. RESULTS: NO REPRODUCIBLE CHANGES IN DNA METHYLATION WERE OBSERVED AFTER INFECTION OF HUH7.5.1 CELLS WITH HCV. LIVERS FROM HBV- AND HCV-INFECTED MICE HAD GENOME-WIDE, TIME-DEPENDENT CHANGES IN DNA METHYLATION, COMPARED WITH UNINFECTED UROKINASE-TYPE PLASMINOGEN ACTIVATOR/SEVERE COMBINED IMMUNODEFICIENT MICE. THERE WERE CHANGES IN 160 +/- 63 GENES IN HBV-INFECTED AND 237 +/- 110 GENES IN HCV-INFECTED MICE. METHYLATION OF 149 COMMON GENES INCREASED IN HBV- AND HCV-INFECTED MICE; METHYLATION OF SOME OF THESE GENES ALSO INCREASED IN HEPATOCELLULAR CARCINOMA SAMPLES FROM PATIENTS COMPARED WITH NONTUMOR TISSUES. EXPRESSION OF IFNG, WHICH IS EXPRESSED BY NATURAL KILLER CELLS, INCREASED SIGNIFICANTLY IN CHIMERIC LIVERS, IN CONCORDANCE WITH INDUCTION OF DNA METHYLATION, AFTER INFECTION WITH HBV OR HCV. INDUCTION OF IFNG WAS REDUCED AFTER ADMINISTRATION OF AN INHIBITOR OF NATURAL KILLER CELL FUNCTION (ANTI-ASIALO GM1). CONCLUSIONS: IN CHIMERIC MICE WITH HUMANIZED LIVERS, INFECTION WITH HBV AND HCV APPEARS TO ACTIVATE A NATURAL KILL CELL-DEPENDENT INNATE IMMUNE RESPONSE. THIS CONTRIBUTES TO THE INDUCTION AND ACCUMULATION OF ABERRANT DNA METHYLATION IN HUMAN HEPATOCYTES. 2014 7 5226 41 PRMT5 RESTRICTS HEPATITIS B VIRUS REPLICATION THROUGH EPIGENETIC REPRESSION OF COVALENTLY CLOSED CIRCULAR DNA TRANSCRIPTION AND INTERFERENCE WITH PREGENOMIC RNA ENCAPSIDATION. CHRONIC HEPATITIS B VIRUS (HBV) INFECTION REMAINS A MAJOR HEALTH PROBLEM WORLDWIDE. THE COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) MINICHROMOSOME, WHICH SERVES AS THE TEMPLATE FOR THE TRANSCRIPTION OF VIRAL RNAS, PLAYS A KEY ROLE IN VIRAL PERSISTENCE. WHILE ACCUMULATING EVIDENCE SUGGESTS THAT CCCDNA TRANSCRIPTION IS REGULATED BY EPIGENETIC MACHINERY, PARTICULARLY THE ACETYLATION OF CCCDNA-BOUND HISTONE 3 (H3) AND H4, THE POTENTIAL CONTRIBUTIONS OF HISTONE METHYLATION AND RELATED HOST FACTORS REMAIN OBSCURE. HERE, BY SCREENING A SERIES OF METHYLTRANSFERASES AND DEMETHYLASES, WE IDENTIFIED PROTEIN ARGININE METHYLTRANSFERASE 5 (PRMT5) AS AN EFFECTIVE RESTRICTOR OF HBV TRANSCRIPTION AND REPLICATION. IN CELL CULTURE-BASED MODELS FOR HBV INFECTION AND IN LIVER TISSUES OF PATIENTS WITH CHRONIC HBV INFECTION, WE FOUND THAT SYMMETRIC DIMETHYLATION OF ARGININE 3 ON H4 ON CCCDNA WAS A REPRESSIVE MARKER OF CCCDNA TRANSCRIPTION AND WAS REGULATED BY PRMT5 DEPENDING ON ITS METHYLTRANSFERASE DOMAIN. MOREOVER, PRMT5-TRIGGERED SYMMETRIC DIMETHYLATION OF ARGININE 3 ON H4 ON THE CCCDNA MINICHROMOSOME INVOLVED AN INTERACTION WITH THE HBV CORE PROTEIN AND THE BRG1-BASED HUMAN SWI/SNF CHROMATIN REMODELER, WHICH RESULTED IN DOWN-REGULATION OF THE BINDING OF RNA POLYMERASE II TO CCCDNA. IN ADDITION TO THE INHIBITORY EFFECT ON CCCDNA TRANSCRIPTION, PRMT5 INHIBITED HBV CORE PARTICLE DNA PRODUCTION INDEPENDENTLY OF ITS METHYLTRANSFERASE ACTIVITY. FURTHER STUDY REVEALED THAT PRMT5 INTERFERED WITH PREGENOMIC RNA ENCAPSIDATION BY PREVENTING ITS INTERACTION WITH VIRAL POLYMERASE PROTEIN THROUGH BINDING TO THE REVERSE TRANSCRIPTASE-RIBONUCLEASE H REGION OF POLYMERASE, WHICH IS CRUCIAL FOR THE POLYMERASE-PREGENOMIC RNA INTERACTION. CONCLUSION: PRMT5 RESTRICTS HBV REPLICATION THROUGH A TWO-PART MECHANISM INCLUDING EPIGENETIC SUPPRESSION OF CCCDNA TRANSCRIPTION AND INTERFERENCE WITH PREGENOMIC RNA ENCAPSIDATION; THESE FINDINGS IMPROVE THE UNDERSTANDING OF EPIGENETIC REGULATION OF HBV TRANSCRIPTION AND HOST-HBV INTERACTION, THUS PROVIDING NEW INSIGHTS INTO TARGETED THERAPEUTIC INTERVENTION. (HEPATOLOGY 2017;66:398-415). 2017 8 2401 39 EPIGENETIC REPROGRAMMING PROMOTES THE ANTIVIRAL ACTION OF IFNALPHA IN HBV-INFECTED CELLS. CHRONIC HEPATITIS B VIRUS (HBV) INFECTIONS REMAIN A HEALTH BURDEN AFFECTING ~250 MILLION PEOPLE WORLDWIDE. THUS FAR, AVAILABLE INTERFERON-ALPHA (IFNALPHA)-BASED THERAPIES HAVE SHOWN UNSATISFACTORY CURE RATES, AND ALTERNATIVE THERAPEUTIC MOLECULES ARE STILL REQUIRED. HOWEVER, THEIR DEVELOPMENT HAS BEEN HAMPERED BECAUSE ACCESSIBLE CELL MODELS SUPPORTING RELEVANT HBV REPLICATION AND APPROPRIATE ANTIVIRAL ACTIVITY ARE LACKING. STRATEGIES THAT REVERSE EPIGENETIC ALTERATIONS OFFER A UNIQUE OPPORTUNITY FOR CELL REPROGRAMMING, WHICH IS VALUABLE FOR RESTORING ALTERED CELLULAR FUNCTIONS IN HUMAN CELL LINES. THIS WORK AIMED TO INVESTIGATE THE FEASIBILITY OF CONVERTING HEPG2 CELLS THAT STABLY OVEREXPRESS THE HBV ENTRY RECEPTOR (SODIUM/TAUROCHOLATE COTRANSPORTING POLYPEPTIDE, NTCP) TOWARD IFNALPHA-RESPONSIVE CELLS USING EPIGENETIC REPROGRAMMING. HEREIN, WE SHOWED THAT AN EPIGENETIC REGIMEN WITH NON-CYTOTOXIC DOSES OF THE DEMETHYLATING COMPOUND 5-AZACYTIDINE RESTORED THE ANTI-HBV ACTION OF IFNALPHA IN EPIGENETICALLY REPROGRAMMED HEPG2-NTCP-C4 CELLS, NAMED REP-HEPG2-NTCP CELLS. THUS, A SIGNIFICANT INHIBITION IN HBV DNA LEVELS WAS MEASURED IN REP-HEPG2-NTCP CELLS AFTER IFNALPHA TREATMENT. THIS INHIBITORY EFFECT WAS ASSOCIATED WITH THE ENHANCEMENT OF IFNALPHA-MEDIATED INDUCTION OF CRITICAL INTERFERON-STIMULATED GENES (ISGS), WHICH WAS LIMITED IN NON-REPROGRAMMED CELLS. IN PARTICULAR, OUR DATA INDICATED THAT RE-EXPRESSION OF 2'-5'-OLIGOADENYLATE SYNTHETASE 1 (OAS1) AND INTERFERON REGULATORY FACTOR 9 (IRF9) WAS THE RESULT OF AN EPIGENETICALLY DRIVEN UNMASKING OF THESE GENES IN REPROGRAMMED CELLS. AT LAST, WE EVALUATED THE THERAPEUTIC POTENTIAL OF THE IFN ANALOG CDM-3008 IN REP-HEPG2-NTCP CELLS AND DEMONSTRATED THE EFFICIENCY OF THIS CHEMICAL COMPOUND IN TRIGGERING ISG INDUCTION AND HBV INHIBITION. IN SUMMARY, THIS STUDY SHOWS THAT EPIGENETIC REPROGRAMMING PROMOTES THE IFNALPHA RESPONSE IN HBV-INFECTED CELLS AND IS POTENTIALLY ATTRACTIVE FOR CELL-BASED EXPERIMENTAL SCREENING OF IFN-LIKE COMPOUNDS. 2021 9 3779 42 INTERFERON ALPHA INDUCES MULTIPLE CELLULAR PROTEINS THAT COORDINATELY SUPPRESS HEPADNAVIRAL COVALENTLY CLOSED CIRCULAR DNA TRANSCRIPTION. COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) OF HEPADNAVIRUSES EXISTS AS AN EPISOMAL MINICHROMOSOME IN THE NUCLEUS OF AN INFECTED HEPATOCYTE AND SERVES AS THE TEMPLATE FOR THE TRANSCRIPTION OF VIRAL MRNAS. IT HAD BEEN DEMONSTRATED BY OTHERS AND US THAT INTERFERON ALPHA (IFN-ALPHA) TREATMENT OF HEPATOCYTES INDUCED A PROLONGED SUPPRESSION OF HUMAN AND DUCK HEPATITIS B VIRUS CCCDNA TRANSCRIPTION, WHICH IS ASSOCIATED WITH THE REDUCTION OF CCCDNA-ASSOCIATED HISTONE MODIFICATIONS SPECIFYING ACTIVE TRANSCRIPTION (H3K9(AC) OR H3K27(AC)), BUT NOT THE HISTONE MODIFICATIONS MARKING CONSTITUTIVE (H3K9(ME3)) OR FACULTATIVE (H3K27(ME3)) HETEROCHROMATIN FORMATION. IN OUR EFFORTS TO IDENTIFY IFN-INDUCED CELLULAR PROTEINS THAT MEDIATE THE SUPPRESSION OF CCCDNA TRANSCRIPTION BY THE CYTOKINE, WE FOUND THAT DOWNREGULATING THE EXPRESSION OF SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION 1 (STAT1), STRUCTURAL MAINTENANCE OF CHROMOSOMES FLEXIBLE HINGE DOMAIN CONTAINING 1 (SMCHD1), OR PROMYELOCYTIC LEUKEMIA (PML) PROTEIN INCREASED BASAL LEVEL OF CCCDNA TRANSCRIPTION ACTIVITY AND PARTIALLY ATTENUATED IFN-ALPHA SUPPRESSION OF CCCDNA TRANSCRIPTION. IN CONTRAST, ECTOPIC EXPRESSION OF STAT1, SMCHD1, OR PML SIGNIFICANTLY REDUCED CCCDNA TRANSCRIPTION ACTIVITY. SMCHD1 IS A NONCANONICAL SMC FAMILY PROTEIN AND IMPLICATED IN EPIGENETIC SILENCING OF GENE EXPRESSION. PML IS A COMPONENT OF NUCLEAR DOMAIN 10 (ND10) AND IS INVOLVED IN SUPPRESSING THE REPLICATION OF MANY DNA VIRUSES. MECHANISTIC ANALYSES DEMONSTRATED THAT STAT1, SMCHD1, AND PML WERE RECRUITED TO CCCDNA MINICHROMOSOMES AND PHENOCOPIED THE IFN-ALPHA-INDUCED POSTTRANSLATIONAL MODIFICATIONS OF CCCDNA-ASSOCIATED HISTONES. WE THUS CONCLUDE THAT STAT1, SMCHD1, AND PML MAY PARTLY MEDIATE THE SUPPRESSIVE EFFECT OF IFN-ALPHA ON HEPADNAVIRAL CCCDNA TRANSCRIPTION.IMPORTANCE PEGYLATED IFN-ALPHA IS THE ONLY THERAPEUTIC REGIMEN THAT CAN INDUCE A FUNCTIONAL CURE OF CHRONIC HEPATITIS B IN A SMALL, BUT SIGNIFICANT, FRACTION OF TREATED PATIENTS. UNDERSTANDING THE MECHANISMS UNDERLYING THE ANTIVIRAL FUNCTIONS OF IFN-ALPHA IN HEPADNAVIRAL INFECTION MAY REVEAL MOLECULAR TARGETS FOR DEVELOPMENT OF NOVEL ANTIVIRAL AGENTS TO IMPROVE THE THERAPEUTIC EFFICACY OF IFN-ALPHA. BY A LOSS-OF-FUNCTION GENETIC SCREENING OF INDIVIDUAL IFN-STIMULATED GENES (ISGS) ON HEPADNAVIRAL MRNAS TRANSCRIBED FROM CCCDNA, WE FOUND THAT DOWNREGULATING THE EXPRESSION OF STAT1, SMCHD1, OR PML SIGNIFICANTLY INCREASED THE LEVEL OF VIRAL RNAS WITHOUT ALTERING THE LEVEL OF CCCDNA. MECHANISTIC ANALYSES INDICATED THAT THOSE CELLULAR PROTEINS ARE RECRUITED TO CCCDNA MINICHROMOSOMES AND INDUCE THE POSTTRANSLATIONAL MODIFICATIONS OF CCCDNA-ASSOCIATED HISTONES SIMILAR TO THOSE INDUCED BY IFN-ALPHA TREATMENT. WE HAVE THUS IDENTIFIED THREE IFN-ALPHA-INDUCED CELLULAR PROTEINS THAT SUPPRESS CCCDNA TRANSCRIPTION AND MAY PARTLY MEDIATE IFN-ALPHA SILENCING OF HEPADNAVIRAL CCCDNA TRANSCRIPTION. 2020 10 3246 27 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 11 3190 39 HCV-INDUCED EPIGENETIC CHANGES ASSOCIATED WITH LIVER CANCER RISK PERSIST AFTER SUSTAINED VIROLOGIC RESPONSE. BACKGROUND & AIMS: CHRONIC HEPATITIS C VIRUS (HCV) INFECTION IS AN IMPORTANT RISK FACTOR FOR HEPATOCELLULAR CARCINOMA (HCC). DESPITE EFFECTIVE ANTIVIRAL THERAPIES, THE RISK FOR HCC IS DECREASED BUT NOT ELIMINATED AFTER A SUSTAINED VIROLOGIC RESPONSE (SVR) TO DIRECT-ACTING ANTIVIRAL (DAA) AGENTS, AND THE RISK IS HIGHER IN PATIENTS WITH ADVANCED FIBROSIS. WE INVESTIGATED HCV-INDUCED EPIGENETIC ALTERATIONS THAT MIGHT AFFECT RISK FOR HCC AFTER DAA TREATMENT IN PATIENTS AND MICE WITH HUMANIZED LIVERS. METHODS: WE PERFORMED GENOME-WIDE CHIPMENTATION-BASED CHIP-SEQ AND RNA-SEQ ANALYSES OF LIVER TISSUES FROM 6 PATIENTS WITHOUT HCV INFECTION (CONTROLS), 18 PATIENTS WITH CHRONIC HCV INFECTION, 8 PATIENTS WITH CHRONIC HCV INFECTION CURED BY DAA TREATMENT, 13 PATIENTS WITH CHRONIC HCV INFECTION CURED BY INTERFERON THERAPY, 4 PATIENTS WITH CHRONIC HEPATITIS B VIRUS INFECTION, AND 7 PATIENTS WITH NONALCOHOLIC STEATOHEPATITIS IN EUROPE AND JAPAN. HCV-INDUCED EPIGENETIC MODIFICATIONS WERE MAPPED BY COMPARATIVE ANALYSES WITH MODIFICATIONS ASSOCIATED WITH OTHER LIVER DISEASE ETIOLOGIES. UPA/SCID MICE WERE ENGRAFTED WITH HUMAN HEPATOCYTES TO CREATE MICE WITH HUMANIZED LIVERS AND GIVEN INJECTIONS OF HCV-INFECTED SERUM SAMPLES FROM PATIENTS; MICE WERE GIVEN DAAS TO ERADICATE THE VIRUS. PATHWAYS ASSOCIATED WITH HCC RISK WERE IDENTIFIED BY INTEGRATIVE PATHWAY ANALYSES AND VALIDATED IN ANALYSES OF PAIRED HCC TISSUES FROM 8 PATIENTS WITH AN SVR TO DAA TREATMENT OF HCV INFECTION. RESULTS: WE FOUND CHRONIC HCV INFECTION TO INDUCE SPECIFIC GENOME-WIDE CHANGES IN H3K27AC, WHICH CORRELATED WITH CHANGES IN EXPRESSION OF MRNAS AND PROTEINS. THESE CHANGES PERSISTED AFTER AN SVR TO DAAS OR INTERFERON-BASED THERAPIES. INTEGRATIVE PATHWAY ANALYSES OF LIVER TISSUES FROM PATIENTS AND MICE WITH HUMANIZED LIVERS DEMONSTRATED THAT HCV-INDUCED EPIGENETIC ALTERATIONS WERE ASSOCIATED WITH LIVER CANCER RISK. COMPUTATIONAL ANALYSES ASSOCIATED INCREASED EXPRESSION OF SPHK1 WITH HCC RISK. WE VALIDATED THESE FINDINGS IN AN INDEPENDENT COHORT OF PATIENTS WITH HCV-RELATED CIRRHOSIS (N = 216), A SUBSET OF WHICH (N = 21) ACHIEVED VIRAL CLEARANCE. CONCLUSIONS: IN AN ANALYSIS OF LIVER TISSUES FROM PATIENTS WITH AND WITHOUT AN SVR TO DAA THERAPY, WE IDENTIFIED EPIGENETIC AND GENE EXPRESSION ALTERATIONS ASSOCIATED WITH RISK FOR HCC. THESE ALTERATIONS MIGHT BE TARGETED TO PREVENT LIVER CANCER IN PATIENTS TREATED FOR HCV INFECTION. 2019 12 3189 40 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 13 3186 35 HBV COVALENTLY CLOSED CIRCULAR DNA MINICHROMOSOMES IN DISTINCT EPIGENETIC TRANSCRIPTIONAL STATES DIFFER IN THEIR VULNERABILITY TO DAMAGE. BACKGROUND AND AIMS: HBV COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) IS A MAJOR OBSTACLE FOR A CURE OF CHRONIC HEPATITIS B. ACCUMULATING EVIDENCE SUGGESTS THAT EPIGENETIC MODIFICATIONS REGULATE THE TRANSCRIPTIONAL ACTIVITY OF CCCDNA MINICHROMOSOMES. HOWEVER, IT REMAINS UNCLEAR HOW THE EPIGENETIC STATE OF CCCDNA AFFECTS ITS STABILITY. APPROACHES AND RESULTS: BY USING HBV INFECTION CELL MODELS AND IN VITRO AND IN VIVO RECOMBINANT CCCDNA (RCCCDNA) AND HBVCIRCLE MODELS, THE REDUCTION RATE OF HBV CCCDNA AND THE EFFICACY OF APOLIPOPROTEIN B MRNA EDITING ENZYME CATALYTIC SUBUNIT 3A (APOBEC3A)-MEDIATED AND CRISPR/CRISPR-ASSOCIATED 9 (CAS9)-MEDIATED CCCDNA TARGETING WERE COMPARED BETWEEN CCCDNAS WITH DISTINCT TRANSCRIPTIONAL ACTIVITIES. INTERFERON-ALPHA TREATMENT AND HEPATITIS B X PROTEIN (HBX) DELETION WERE APPLIED AS TWO STRATEGIES FOR CCCDNA REPRESSION. CHROMATIN IMMUNOPRECIPITATION AND MICROCOCCAL NUCLEASE ASSAYS WERE PERFORMED TO DETERMINE THE EPIGENETIC PATTERN OF CCCDNA. HBV CCCDNA LEVELS REMAINED STABLE IN NONDIVIDING HEPATOCYTES; HOWEVER, THEY WERE SIGNIFICANTLY REDUCED DURING CELL DIVISION, AND THE REDUCTION RATE WAS SIMILAR BETWEEN CCCDNAS IN TRANSCRIPTIONALLY ACTIVE AND TRANSCRIPTIONALLY REPRESSED STATES. STRIKINGLY, HBV RCCCDNA WITHOUT HBX EXPRESSION EXHIBITED A SIGNIFICANTLY LONGER PERSISTENCE IN MICE. THE CCCDNA WITH LOW TRANSCRIPTIONAL ACTIVITY EXHIBITED AN EPIGENETICALLY INACTIVE PATTERN AND WAS MORE DIFFICULT TO ACCESS BY APOBEC3A AND ENGINEERED CRISPR-CAS9. THE EPIGENETIC REGULATOR ACTIVATING CCCDNA INCREASED ITS VULNERABILITY TO APOBEC3A. CONCLUSIONS: HBV CCCDNA MINICHROMOSOMES IN DISTINCT EPIGENETIC TRANSCRIPTIONAL STATES SHOWED A SIMILAR REDUCTION RATE DURING CELL DIVISION BUT SIGNIFICANTLY DIFFERED IN THEIR ACCESSIBILITY AND VULNERABILITY TO TARGETED NUCLEASES AND ANTIVIRAL AGENTS. EPIGENETIC SENSITIZATION OF CCCDNA MAKES IT MORE SUSCEPTIBLE TO DAMAGE AND MAY POTENTIALLY CONTRIBUTE TO AN HBV CURE. 2022 14 3780 44 INTERFERON DRIVES HCV SCARRING OF THE EPIGENOME AND CREATES TARGETABLE VULNERABILITIES FOLLOWING VIRAL CLEARANCE. BACKGROUND AND AIMS: CHRONIC HCV INFECTION IS A LEADING ETIOLOGIC DRIVER OF CIRRHOSIS AND ULTIMATELY HCC. OF THE APPROXIMATELY 71 MILLION INDIVIDUALS CHRONICALLY INFECTED WITH HCV, 10%-20% ARE EXPECTED TO DEVELOP SEVERE LIVER COMPLICATIONS IN THEIR LIFETIME. EPIGENETIC MECHANISMS INCLUDING DNA METHYLATION AND HISTONE MODIFICATIONS BECOME PROFOUNDLY DISRUPTED IN DISEASE PROCESSES INCLUDING LIVER DISEASE. APPROACH AND RESULTS: TO UNDERSTAND HOW HCV INFECTION INFLUENCES THE EPIGENOME AND WHETHER THESE EVENTS REMAIN AS "SCARS" FOLLOWING CURE OF CHRONIC HCV INFECTION, WE MAPPED GENOME-WIDE DNA METHYLATION, FOUR KEY REGULATORY HISTONE MODIFICATIONS (H3K4ME3, H3K4ME1, H3K27AC, AND H3K27ME3), AND OPEN CHROMATIN IN PARENTAL AND HCV-INFECTED IMMORTALIZED HEPATOCYTES AND THE HUH7.5 HCC CELL LINE, ALONG WITH DNA METHYLATION AND GENE-EXPRESSION ANALYSES FOLLOWING ELIMINATION OF HCV IN THESE MODELS THROUGH TREATMENT WITH INTERFERON-ALPHA (IFN-ALPHA) OR A DIRECT-ACTING ANTIVIRAL (DAA). OUR DATA DEMONSTRATE THAT HCV INFECTION PROFOUNDLY AFFECTS THE EPIGENOME (PARTICULARLY ENHANCERS); HCV SHARES EPIGENETIC TARGETS WITH INTERFERON-ALPHA TARGETS; AND AN OVERWHELMING MAJORITY OF EPIGENETIC CHANGES INDUCED BY HCV REMAIN AS "SCARS" ON THE EPIGENOME FOLLOWING VIRAL CURE. SIMILAR FINDINGS ARE OBSERVED IN PRIMARY HUMAN PATIENT SAMPLES CURED OF CHRONIC HCV INFECTION. SUPPLEMENTATION OF IFN-ALPHA/DAA ANTIVIRAL REGIMENS WITH DNA METHYLTRANSFERASE INHIBITOR 5-AZA-2'-DEOXYCYTIDINE SYNERGIZES IN REVERTING ABERRANT DNA METHYLATION INDUCED BY HCV. FINALLY, BOTH HCV-INFECTED AND CURED CELLS DISPLAYED A BLUNTED IMMUNE RESPONSE, DEMONSTRATING A FUNCTIONAL EFFECT OF EPIGENETIC SCARRING. CONCLUSIONS: INTEGRATION OF EPIGENETIC AND TRANSCRIPTIONAL DATA ELUCIDATE KEY GENE DEREGULATION EVENTS DRIVEN BY HCV INFECTION AND HOW THIS MAY UNDERPIN THE LONG-TERM ELEVATED RISK FOR HCC IN PATIENTS CURED OF HCV DUE TO EPIGENOME SCARRING. 2022 15 3782 35 INTERFERON THERAPY OF CHRONIC HEPATITIS B. CHRONIC HEPATITIS B (CHB) RESULTS FROM THE INABILITY OF THE HOST'S IMMUNE SYSTEM TO CONTROL VIRAL REPLICATION. INTERFERON-ALPHA (IFN-ALPHA) THERAPY CAN CONVERT CHB INTO INACTIVE HEPATITIS B VIRUS (HBV) INFECTION IN 20-30% OF THE TREATED PATIENTS. IN SPITE OF THE LOW RESPONSE RATE, IFN-ALPHA THERAPY HAS THE ADVANTAGE OF HAVING A LIMITED DURATION AND BEING EFFECTIVE EVEN AFTER THERAPY, AS DEMONSTRATED BY A MUCH HIGHER INCIDENCE OF HBSAG CLEARANCE IN RESPONDERS TO IFN-ALPHA THAN IN NATURALLY OCCURRING INACTIVE HBSAG CARRIERS. IFN-ALPHA HAS MULTIPLE ANTIVIRAL, ANTIPROLIFERATIVE, AND IMMUNOMODULATORY ACTIVITIES AND TARGETS: CELLULAR GENES (IFN-STIMULATED GENES) ACTIVATING DIFFERENT PATHWAYS OF ANTIVIRAL DEFENSE IN INFECTED AND NONINFECTED CELLS, HBV REPLICATION BLOCKING THE RNA-CONTAINING CORE PARTICLE FORMATION AND ACCELERATING THEIR DECAY, DEGRADING PREGENOMIC RNA, AND MODULATING THE NUCLEAR VIRAL MINICHROMOSOME (COVALENTLY CLOSED CIRCULAR DNA) ACTIVITY BY TARGETING ITS EPIGENETIC REGULATION AND BOTH INNATE AND ADAPTIVE IMMUNE RESPONSE. THE INTERFERENCE OF VIRAL HETEROGENEITY AND GENETIC POLYMORPHISMS OF THE HOST ON IFN-ALPHA SUSCEPTIBILITY IS UNDER INVESTIGATION. ONLY A BETTER UNDERSTANDING OF THE COMPLEX INTERPLAY BETWEEN THE DIFFERENT ACTIVITIES OF IFN-ALPHA WOULD WARRANT THE AMELIORATION OF CURRENT THERAPEUTIC STRATEGIES AND THE DESIGN OF NEW THERAPEUTIC APPROACHES. THE STUDY OF ON-TREATMENT DYNAMICS OF HBV INFECTION BY MEANS OF COMBINED QUANTITATIVE MONITORING OF SERUM HBV DNA AND HBSAG WARRANT TAILORING TREATMENT AT THE SINGLE-PATIENT LEVEL AND CAN HELP TO MAKE TREATMENT MORE COST-EFFECTIVE BY USING THE DIFFERENT COMBINATIONS OF CURRENTLY AVAILABLE ANTIVIRALS, INCLUDING IFN, MORE APPROPRIATELY. INTEGRATED MOLECULAR AND CLINICAL KNOWLEDGE IN A SYSTEMS MEDICINE FASHION IS MANDATORY TO FURTHER IMPROVE ANTIVIRAL THERAPY IN CHB. 2014 16 5700 30 SINGLE NUCLEOTIDE POLYMORPHISM IN DNMT3B PROMOTER AND THE RISK FOR IDIOPATHIC THROMBOCYTOPENIC PURPURA IN CHINESE POPULATION. OBJECTIVE: EPIGENETIC CHANGES IN GENE EXPRESSION, INCLUDING DNA METHYLATION AND HISTONE MODIFICATIONS, MIGHT CONTRIBUTE TO AUTOIMMUNITY. DNA METHYLATION IS MEDIATED BY A FAMILY OF DNA METHYLTRANSFERASES. POLYMORPHISMS OF THE DNA METHYLTRANSFERASE 3B (DNMT3B) GENE MAY INFLUENCE DNMT3B ACTIVITY ON DNA METHYLATION, THEREBY MODULATING THE SUSCEPTIBILITY TO SOME DISEASES. THE PURPOSE OF THIS STUDY WAS TO INVESTIGATE THE ASSOCIATION BETWEEN THE SINGLE NUCLEOTIDE POLYMORPHISM (SNP) IN PROMOTER OF THE DNMT3B GENE AND THE RISK FOR DEVELOPMENT OF IDIOPATHIC THROMBOCYTOPENIC PURPURA (ITP). METHODS: IN THIS HOSPITAL-BASED CASE-CONTROL STUDY, THE DNMT3B SNP WAS GENOTYPED IN 201 PATIENTS WITH ITP AND 136 HEALTHY CONTROLS BY POLYMERASE CHAIN REACTION-RESTRICTION FRAGMENT LENGTH POLYMORPHISM. RESULTS: THE C/C GENOTYPE WAS NOT DETECTED IN BOTH THE PATIENTS WITH ITP AND THE CONTROLS. IN THE CONTROLS, THE FREQUENCIES OF T/T AND C/T GENOTYPES AND T AND C ALLELES WERE 97.8%, 2.2%, 98.9%, AND 1.1%, RESPECTIVELY. THERE WAS NO SIGNIFICANT DIFFERENCE IN GENOTYPE AND ALLELE DISTRIBUTION BETWEEN THE PATIENTS WITH ITP AND THE CONTROLS (P = 0.745 AND 0.747, RESPECTIVELY). NO SIGNIFICANT DIFFERENCE WAS OBSERVED IN GENOTYPE AND ALLELE DISTRIBUTION BETWEEN THE TWO GROUPS WHEN STRATIFIED BY THE AGE. THE SIMILAR RESULTS WERE SHOWN AMONG THE FOUR GROUPS OF PATIENTS WITH ITP: ACUTE CHILDHOOD, CHRONIC CHILDHOOD, ACUTE ADULT, AND CHRONIC ADULT. CONCLUSION: THIS POLYMORPHISM WAS DISTRIBUTED SIMILARLY BETWEEN THE PATIENTS WITH ITP AND THE CONTROLS. IT DEMONSTRATED THAT IT MAY NOT BE USED AS A STRATIFICATION MARKER TO PREDICT THE SUSCEPTIBILITY TO ITP, AT LEAST IN THE POPULATION OF NORTH CHINA. 2008 17 5547 34 ROLE OF EPIGENETIC MODIFICATION IN INTERFERON TREATMENT OF HEPATITIS B VIRUS INFECTION. HUMAN HEPATITIS B VIRUS (HBV) IS A SMALL, ENVELOPED DNA VIRUS THAT CAUSES ACUTE AND CHRONIC HEPATITIS. CHRONIC HEPATITIS B (CHB) IS ASSOCIATED WITH HEPATOCELLULAR CARCINOMA PATHOGENESIS. INTERFERONS (IFNS) HAVE BEEN USED FOR THE TREATMENT OF CHB FOR A LONG TIME, WITH ADVANTAGES INCLUDING LESS TREATMENT DURATION AND SUSTAINED VIROLOGICAL RESPONSE. PRESENTLY, VARIOUS EVIDENCE SUGGESTS THAT EPIGENETIC MODIFICATION OF THE VIRAL COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) AND THE HOST GENOME IS CRUCIAL FOR THE REGULATION OF VIRAL ACTIVITY. THIS MODIFICATION INCLUDES HISTONE ACETYLATION, DNA METHYLATION, N6-METHYLADENOSINE, AND NON-CODING RNA MODIFICATION. IFN TREATMENT FOR CHB CAN STIMULATE MULTIPLE IFN-STIMULATED GENES FOR INHIBITING VIRUS REPLICATION. IFNS CAN ALSO AFFECT THE HBV LIFE CYCLE THROUGH EPIGENETIC MODULATION. IN THIS REVIEW, WE SUMMARIZED THE DIFFERENT MECHANISMS THROUGH WHICH IFN-ALPHA INHIBITS HBV REPLICATION, INCLUDING EPIGENETIC REGULATION. MOREOVER, THE MECHANISMS UNDERLYING IFN ACTIVITY ARE DISCUSSED, WHICH INDICATED ITS POTENTIAL AS A NOVEL TREATMENT FOR CHB. IT IS PROPOSED THAT EPIGENETIC CHANGES SUCH AS HISTONE ACETYLATION, DNA METHYLATION, M6A METHYLATION COULD BE THE TARGETS OF IFN, WHICH MAY OFFER A NOVEL APPROACH TO HBV TREATMENT. 2022 18 3794 31 INTERLEUKIN-33 MEDIATES BOTH IMMUNE-RELATED AND NON-IMMUNE-RELATED INHIBITORY EFFECTS AGAINST HEPATITIS B VIRUS. CHRONIC INFECTION BY HEPATITIS B VIRUS (HBV) IS ASSOCIATED WITH HIGH RISKS OF LIVER FIBROSIS, CIRRHOSIS AND HEPATOCELLULAR CARCINOMA. HBV COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) IN THE NUCLEUS OF INFECTED HEPATOCYTE SERVES AS TRANSCRIPTION TEMPLATE. NEITHER NATURAL RESOLUTION OF ACUTE INFECTION NOR CURRENT TREATMENT OPTIONS FOR CHRONIC INFECTION ARE BELIEVED TO CAUSE CCCDNA CLEARANCE. WE PREVIOUSLY SHOWED THAT INJECTION OF IL-33-EXPRESSING PLASMID FACILITATED CLEARANCE OF INTRAHEPATIC HBV DNA IN A MOUSE MODEL OF HBV PERSISTENCE. IN THIS WORK, HBV-TARGETING THERAPEUTIC EFFECTS OF IL-33 WERE FURTHER EXPLORED. MURINE IL-33 DELIVERED BY RECOMBINANT ADENO-ASSOCIATED VIRUS (AAV-MIL-33) INDUCED CLEARANCE OF BOTH SERUM HBV MARKERS AND INTRAHEPATIC HBV DNA IN TWO MOUSE MODELS OF HBV PERSISTENCE BASED ON REPLICON PLASMID AND RECOMBINANT CCCDNA (RCCCDNA) RESPECTIVELY. CLEARANCE WAS ASSOCIATED WITH SERUM ALT ELEVATIONS AND LIVER INFILTRATIONS BY CD4(+) AND CD8(+) T CELLS, INDICATING IL-33-INDUCED CELLULAR IMMUNE RESPONSES AGAINST HBV-HARBORING CELLS. ADOPTIVE TRANSFER OF SPLENOCYTES FROM AAV-MIL-33-CURED MICE WAS INDEED SUFFICIENT TO ENGENDER SIMILAR CLEARANCE IN RECIPIENT MICE. IN VITRO, INTRACELLULAR, INSTEAD OF EXTRACELLULAR, IL-33 WAS MAINLY RESPONSIBLE FOR REPRESSING VIRAL TRANSCRIPTION, PROTEIN PRODUCTION AND GENOME REPLICATION IN HUH7 CELLS TRANSFECTED WITH HBV REPLICON OR RCCCDNA. IL-33 WAS SHOWN TO BE RECRUITED ONTO RCCCDNA MINICHROMOSOME ACCOMPANIED BY LOSS OF TRANSCRIPTIONAL ACTIVATION EPIGENETIC MARKS. FINALLY, TRANSFECTION OF IL-33 INTO HBV-INFECTED HEPG2/NTCP CELLS RESULTED IN REDUCED TRANSCRIPTION, ANTIGEN EXPRESSION AND GENOME REPLICATION, SUGGESTING REPRESSION OF CANONICAL CCCDNA. THESE DATA DEMONSTRATED DIVERSE INHIBITORY EFFECTS ON HBV AND HBV-INFECTED CELLS MEDIATED BY IL-33, AND SUGGEST IL-33 AS AN INTERESTING THERAPEUTIC CANDIDATE. 2022 19 6747 33 WHOLE GENOME 5'-METHYLCYTOSINE LEVEL QUANTIFICATION IN CIRRHOTIC HCV-INFECTED EGYPTIAN PATIENTS WITH AND WITHOUT HEPATOCELLULAR CARCINOMA. DNA METHYLATION IS AN EPIGENETIC MECHANISM USED BY CELLS TO CONTROL GENE EXPRESSION. DNA METHYLATION IS A COMMONLY USED EPIGENETIC SIGNALING TOOL THAT CAN HOLD GENES IN THE "OFF" POSITION. CHRONIC INFECTION WITH HEPATITIS C VIRUS (HCV) IS CONSIDERED A MAJOR RISK FOR CHRONIC LIVER IMPAIRMENT. IT IS THE MOST COMMON LEADING CAUSE OF HCC. THE PRESENT WORK IS AIMED AT STUDYING WHOLE GENOME 5'-METHYLCYTOSINE LEVELS IN CIRRHOTIC HCV-INFECTED EGYPTIAN PATIENTS. IN THE PRESENT STUDY, 120 EGYPTIAN ADULTS WERE INCLUDED. THEY WERE DIVIDED INTO TWO GROUPS: GROUP CAPITAL I, UKRAINIAN (40 APPARENTLY HEALTHY CONTROL SUBJECTS) AND GROUP CAPITAL I, UKRAINIANCAPITAL I, UKRAINIAN (80 HCV-INFECTED PATIENTS). FURTHERMORE, GROUP II WAS SUBDIVIDED INTO 2 SUBGROUPS ACCORDING TO THE PRESENCE OF HCC IN HCV-INFECTED SUBJECTS. TO ALL STUDIED SUBJECTS, THE LEVEL OF 5-MC% WAS MEASURED IN PERIPHERAL BLOOD. IN THE PRESENT STUDY, THE MEDIAN OF 5'-METHYLCYTOSINE% IN THE CONTROL GROUP (GROUP I) WAS 2.5, IN THE HCV GROUP (GROUP IIA) WAS 2.45, AND IN THE HCC GROUP (GROUP II B) WAS 2.25. A STEPWISE DECREASE IN 5'-METHYLCYTOSINE% FROM THE CONTROL (GROUP I) TOWARD HCC (GROUP IIB) WAS OBSERVED, TAKING INTO CONSIDERATION THAT THE STEPWISE GLOBAL HYPOMETHYLATION WAS NOT STATISTICALLY SIGNIFICANT (P = 0.811). THERE WAS A NEGATIVE CORRELATION BETWEEN ALT AND 5'-METHYLCYTOSINE% (P = -0.029). FROM THIS STUDY, WE CAN CONCLUDE THAT GLOBAL DNA 5'-METHYLCYTOSINE% DOES NOT DIFFER IN HCV-INFECTED CIRRHOTIC PATIENTS AND HCC PATIENTS WHEN COMPARED TO NORMAL CONTROLS. CONSECUTIVELY, WE HAD CONCLUDED THAT THERE IS NO IMPACT OF 5'-METHYLCYTOSINE% ON THE DEVELOPMENT OF LIVER CIRRHOSIS OR HCC. MOREOVER, THE NEGATIVE CORRELATION BETWEEN 5'-METHYLCYTOSINE% AND SERUM ALT LEVEL DENOTES A TREND OF DECREASE IN 5'-METHYLCYTOSINE% WITH MORE LIVER DAMAGE. 2020 20 3185 24 HBC BINDS TO THE CPG ISLANDS OF HBV CCCDNA AND PROMOTES AN EPIGENETIC PERMISSIVE STATE. HBV COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) IS THE TEMPLATE FOR THE TRANSCRIPTION OF HBV. HBV CORE PROTEIN (HBC) IS A MAIN COMPONENT OF THE HBV CCCDNA MINICHROMOSOME. HOWEVER, THE FUNCTION OF HBC IN CCCDNA IS NOT FULLY UNDERSTOOD. IN LIGHT OF RECENT FINDINGS THAT HBV CCCDNA MAY BE REGULATED EPIGENETICALLY, WE ANALYZED THE BINDING OF HBC TO CCCDNA AND THE IMPACT OF HBC ON CCCDNA EPIGENETIC PROFILE IN THE LIVER BIOPSY SAMPLES OF 22 PATIENTS WITH CHRONIC HEPATITIS B (CHB). WE FOUND THAT HBC BINDING TO HBV CCCDNA OCCURRED PREFERENTIALLY AT CPG ISLAND 2, AN IMPORTANT REGION FOR THE REGULATION OF HBV TRANSCRIPTION. FURTHERMORE, THE RELATIVE ABUNDANCES OF HBC BINDING TO CPG ISLAND 2 WERE POSITIVELY CORRELATED WITH THE RATIOS OF RELAXED CIRCULAR DNA TO CCCDNA AND THE LEVELS OF SERUM HBV DNA IN THOSE PATIENTS. INTERESTINGLY, THE RELATIVE ABUNDANCES OF HBC BINDING TO CPG ISLAND 2 WERE ASSOCIATED WITH THE BINDING OF CREB BINDING PROTEIN (CBP) AND WITH HYPOMETHYLATION IN CPG ISLAND 2 OF HBV CCCDNA MINICHROMOSOMES. HOWEVER, RELATIVELY HIGHER AMOUNTS OF HBC BINDING TO CPG ISLAND 2 OF CCCDNA WERE ACCOMPANIED BY LOWER AMOUNTS OF HDAC1 BINDING. MULTIVARIATE ANALYSIS REVEALED THAT THE ABUNDANCES OF HBC BINDING TO CPG ISLAND 2 OF CCCDNA AND POSITIVE HBEAG WERE INDEPENDENT FACTORS ASSOCIATED WITH THE REPLICATION OF HBV (P = 0.001 FOR BOTH). APPARENTLY, HBC IS A POSITIVE REGULATOR OF HBV TRANSCRIPTION AND REPLICATION, MAINTAINING THE PERMISSIVE EPIGENETIC STATE IN THE CRITICAL REGION OF THE HBV CCCDNA MINICHROMOSOMES. 2011