1 3794 156 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 2 5867 38 SUPPRESSIVE EFFECT OF THE HISTONE DEACETYLASE INHIBITOR SUBEROYLANILIDE HYDROXAMIC ACID (SAHA) ON HEPATITIS C VIRUS REPLICATION. THE HISTONE DEACETYLASE (HDAC) INHIBITOR SUBEROYLANILIDE HYDROXAMIC ACID (SAHA) HAS A CLINICAL PROMISE FOR TREATMENT OF CANCER INCLUDING HEPATOCELLULAR CARCINOMA (HCC). TO INVESTIGATE EFFECT OF SAHA ON HEPATITIS C VIRUS (HCV) REPLICATION, WE TREATED THE HCV REPLICON CELL OR6 WITH SAHA. HCV REPLICATION WAS SIGNIFICANTLY INHIBITED BY SAHA AT CONCENTRATIONS BELOW 1 MUM WITH NO CELLULAR TOXICITY. ANOTHER HDAC INHIBITOR, TRICOSTATIN A, ALSO SHOWED REDUCTION OF HCV REPLICATION. THE MICROARRAY ANALYSIS AND QUANTITATIVE RT-PCR DEMONSTRATED UP-REGULATION OF OSTEOPONTIN (OPN) AND DOWN-REGULATION OF APOLIPOPROTEIN-A1 (APO-A1) AFTER SAHA TREATMENT. DIRECT GENE INDUCTION OF OPN AND KNOCKDOWN OF APO-A1 ALSO SHOWED REDUCTION OF HCV REPLICATION. THE LIVER SPECIFIC MICRORNA-122, WHICH IS INVOLVED IN HCV REPLICATION, WAS NOT AFFECTED BY SAHA TREATMENT. THESE RESULTS SUGGEST THAT SAHA HAS SUPPRESSIVE EFFECT ON HCV REPLICATION THROUGH ALTERATIONS OF GENE EXPRESSION SUCH AS OPN AND APO-A1 IN HOST CELLS. EPIGENETIC TREATMENT WITH HDAC INHIBITORS MAY BE A NOVEL THERAPEUTIC APPROACH FOR DISEASES ASSOCIATED WITH HCV INFECTION SUCH AS CHRONIC HEPATITIS, LIVER CIRRHOSIS, AND HCC. 2013 3 1664 36 DOWNREGULATION OF GADD45BETA EXPRESSION BY HEPATITIS C VIRUS LEADS TO DEFECTIVE CELL CYCLE ARREST. MEMBERS OF THE GADD45 FAMILY PLAY CENTRAL ROLES IN THE CELLULAR RESPONSE TO GENOTOXIC STRESS AND HAVE BEEN IMPLICATED IN SEVERAL HUMAN CANCERS, INCLUDING HEPATOCELLULAR CARCINOMAS. CHRONIC INFECTION BY HEPATITIS C VIRUS (HCV) IS A MAJOR RISK FACTOR FOR THE ONSET AND DEVELOPMENT OF PRIMARY HEPATOCELLULAR TUMORS, ALTHOUGH THE UNDERLYING MECHANISMS ARE UNCLEAR. HERE, WE SHOW A NOVEL LINK BETWEEN DIMINISHED GADD45BETA EXPRESSION AND HCV INFECTION. INHIBITED GADD45BETA EXPRESSION WAS OBSERVED IN BOTH NONTUMORAL AND TUMORAL TISSUES FROM INFECTED INDIVIDUALS, AND IN CELL LINES HARBORING A HCV REPLICON AND THE INFECTIOUS HCV STRAIN JFH1. DECREASED GADD45BETA EXPRESSION WAS CONFIRMED IN VIVO IN A TRANSGENIC MURINE MODEL EXPRESSING THE ENTIRE HCV OPEN READING FRAME. MECHANISTICALLY, HYPERMETHYLATION OF THE GADD45BETA PROMOTER IN THE PRESENCE OF HCV IS RESPONSIBLE FOR THIS DEFECT. DIMINISHED GADD45BETA EXPRESSION LEADS TO ABERRANT CELL CYCLE ARREST AND DIMINISHED DNA EXCISION REPAIR. TOGETHER, THESE RESULTS PROVIDE A NOVEL INSIGHT INTO THE MECHANISMS INVOLVED IN HCV-ASSOCIATED HEPATOCELLULAR CARCINOMAS, SHOWING THAT REDUCED GADD45BETA EXPRESSION MAY PLAY A CONTRIBUTORY ROLE TO THIS PROCESS, AND PROVIDING EVIDENCE THAT HCV MAY INTERFERE WITH EPIGENETIC GENE EXPRESSION BY ALTERING PROMOTER METHYLATION. 2010 4 3186 45 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 5 442 29 ANTIVIRAL THERAPIES FOR HEPATITIS B VIRUS-RELATED HEPATOCELLULAR CARCINOMA. CHRONIC HEPATITIS B VIRUS (HBV) INFECTION IS A CRITICAL RISK FACTOR FOR THE CARCINOGENESIS AND PROGRESSION OF HEPATOCELLULAR CARCINOMA (HCC). IT PROMOTES HCC DEVELOPMENT BY INDUCING LIVER FIBROGENESIS, GENETIC AND EPIGENETIC ALTERATIONS, AND THE EXPRESSION OF ACTIVE VIRAL-CODED PROTEINS. EFFECTIVE ANTIVIRAL TREATMENTS INHIBIT THE REPLICATION OF HBV, REDUCE SERUM VIRAL LOAD AND ACCELERATE HEPATITIS B E ANTIGEN SERUM CONVERSION. TIMELY INITIATION OF ANTIVIRAL TREATMENT IS NOT ONLY ESSENTIAL FOR PREVENTING THE INCIDENCE OF HCC IN CHRONIC HEPATITIS B PATIENTS, BUT ALSO IMPORTANT FOR REDUCING HBV REACTIVATION, IMPROVING LIVER FUNCTION, REDUCING OR DELAYING HCC RECURRENCE, AND PROLONGING OVERALL SURVIVAL OF HBV-RELATED HCC PATIENTS AFTER CURATIVE AND PALLIATIVE THERAPIES. THE SELECTION OF ANTIVIRAL DRUGS, MONITORING OF INDICATORS SUCH AS HBV DNA AND HEPATITIS B SURFACE ANTIGEN, AND TIMELY RESCUE TREATMENT WHEN NECESSARY, ARE ESSENTIAL IN ANTIVIRAL THERAPIES FOR HBV-RELATED HCC. 2015 6 5803 39 STING SIGNALING ACTIVATION INHIBITS HBV REPLICATION AND ATTENUATES THE SEVERITY OF LIVER INJURY AND HBV-INDUCED FIBROSIS. THE COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) OF HBV PLAYS A CRUCIAL ROLE IN VIRAL PERSISTENCE AND IS ALSO A RISK FACTOR FOR DEVELOPING HBV-INDUCED DISEASES, INCLUDING LIVER FIBROSIS. STIMULATOR OF INTERFERON GENES (STING), A MASTER REGULATOR OF DNA-MEDIATED INNATE IMMUNE ACTIVATION, IS A POTENTIAL THERAPEUTIC TARGET FOR VIRAL INFECTION AND VIRUS-RELATED DISEASES. IN THIS STUDY, AGONIST-INDUCED STING SIGNALING ACTIVATION IN MACROPHAGES WAS REVEALED TO INHIBIT CCCDNA-MEDIATED TRANSCRIPTION AND HBV REPLICATION VIA EPIGENETIC MODIFICATION IN HEPATOCYTES. NOTABLY, STING ACTIVATION COULD EFFICIENTLY ATTENUATE THE SEVERITY OF LIVER INJURY AND FIBROSIS IN A CHRONIC RECOMBINANT CCCDNA (RCCCDNA) MOUSE MODEL, WHICH IS A PROVEN SUITABLE RESEARCH PLATFORM FOR HBV-INDUCED FIBROSIS. MECHANISTICALLY, STING-ACTIVATED AUTOPHAGIC FLUX COULD SUPPRESS MACROPHAGE INFLAMMASOME ACTIVATION, LEADING TO THE AMELIORATION OF LIVER INJURY AND HBV-INDUCED FIBROSIS. OVERALL, THE ACTIVATION OF STING SIGNALING COULD INHIBIT HBV REPLICATION THROUGH EPIGENETIC SUPPRESSION OF CCCDNA AND ALLEVIATE HBV-INDUCED LIVER FIBROSIS THROUGH THE SUPPRESSION OF MACROPHAGE INFLAMMASOME ACTIVATION BY ACTIVATING AUTOPHAGIC FLUX IN A CHRONIC HBV MOUSE MODEL. THIS STUDY SUGGESTS THAT TARGETING THE STING SIGNALING PATHWAY MAY BE AN IMPORTANT THERAPEUTIC STRATEGY TO PROTECT AGAINST PERSISTENT HBV REPLICATION AND HBV-INDUCED FIBROSIS. 2022 7 2837 48 FORKHEAD O TRANSCRIPTION FACTOR 4 RESTRICTS HBV COVALENTLY CLOSED CIRCULAR DNA TRANSCRIPTION AND HBV REPLICATION THROUGH GENETIC DOWNREGULATION OF HEPATOCYTE NUCLEAR FACTOR 4 ALPHA AND EPIGENETIC SUPPRESSION OF COVALENTLY CLOSED CIRCULAR DNA VIA INTERACTING WITH PROMYELOCYTIC LEUKEMIA PROTEIN. NUCLEAR LOCATED HEPATITIS B VIRUS (HBV) COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) REMAINS THE KEY OBSTACLE TO CURE CHRONIC HEPATITIS B (CHB). IN OUR PREVIOUS INVESTIGATION, IT WAS FOUND THAT FOXO4 COULD INHIBIT HBV CORE PROMOTER ACTIVITY THROUGH DOWNREGULATING THE EXPRESSION OF HNF4ALPHA. HOWEVER, THE EXACT MECHANISMS WHEREBY FOXO4 INHIBITS HBV REPLICATION, ESPECIALLY ITS EFFECT ON CCCDNA, REMAIN UNCLEAR. HERE, OUR DATA FURTHER REVEALED THAT FOXO4 COULD EFFECTIVELY INHIBIT CCCDNA MEDIATED TRANSCRIPTION AND HBV REPLICATION WITHOUT AFFECTING CCCDNA LEVEL. MECHANISTIC STUDY SHOWED THAT FOXO4 COULD CAUSE EPIGENETIC SUPPRESSION OF CCCDNA. ALTHOUGH FOXO4-MEDIATED DOWNREGULATION OF HNF4ALPHA CONTRIBUTED TO INHIBITING HBV CORE PROMOTER ACTIVITY, IT HAD LITTLE EFFECT ON CCCDNA EPIGENETIC REGULATION. FURTHER, IT WAS FOUND THAT FOXO4 COULD COLOCALIZE WITHIN PROMYELOCYTIC LEUKEMIA PROTEIN (PML) NUCLEAR BODIES AND INTERACT WITH PML. OF NOTE, PML WAS REVEALED TO BE CRITICAL FOR FOXO4-MEDIATED INHIBITION OF CCCDNA EPIGENETIC MODIFICATION AND OF THE FOLLOWING CCCDNA TRANSCRIPTION AND HBV REPLICATION. FURTHERMORE, FOXO4 WAS FOUND TO BE DOWNREGULATED IN HBV-INFECTED HEPATOCYTES AND HUMAN LIVER TISSUES, AND IT WAS NEGATIVELY CORRELATED WITH CCCDNA TRANSCRIPTIONAL ACTIVITY IN CHB PATIENTS. TOGETHER, THESE FINDINGS HIGHLIGHT THE ROLE OF FOXO4 IN SUPPRESSING CCCDNA TRANSCRIPTION AND HBV REPLICATION VIA GENETIC DOWNREGULATION OF HNF4ALPHA AND EPIGENETIC SUPPRESSION OF CCCDNA THROUGH INTERACTING WITH PML. TARGETING FOXO4 MAY PRESENT AS A NEW THERAPEUTIC STRATEGY AGAINST CHRONIC HBV INFECTION. IMPORTANCE HBV CCCDNA IS A DETERMINING FACTOR FOR VIRAL PERSISTENCE AND THE MAIN OBSTACLE FOR A CURE OF CHRONIC HEPATITIS B. STRATEGIES THAT TARGET CCCDNA DIRECTLY ARE THEREFORE OF GREAT IMPORTANCE IN CONTROLLING PERSISTENT HBV INFECTION. IN PRESENT INVESTIGATION, WE FOUND THAT FOXO4 COULD EFFICIENTLY SUPPRESS CCCDNA TRANSCRIPTION AND HBV REPLICATION WITHOUT AFFECTING THE LEVEL OF CCCDNA ITSELF. FURTHER, OUR DATA REVEALED THAT FOXO4 MIGHT INHIBIT CCCDNA FUNCTION VIA A TWO-PART MECHANISM: ONE IS TO EPIGENETICALLY SUPPRESS CCCDNA TRANSCRIPTION VIA INTERACTING WITH PML, AND THE OTHER IS TO INHIBIT HBV CORE PROMOTER ACTIVITY VIA THE GENETIC DOWNREGULATION OF HNF4ALPHA. OF NOTE, HBV MIGHT DAMPEN THE EXPRESSION OF FOXO4 FOR ITS OWN PERSISTENT INFECTION. WE PROPOSE THAT MANIPULATION OF FOXO4 MAY PRESENT AS A POTENTIAL THERAPEUTIC STRATEGY AGAINST CHRONIC HBV INFECTION. 2022 8 4239 39 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 9 3255 38 HEPATITIS B VIRUS X PROTEIN MEDIATED EPIGENETIC ALTERATIONS IN THE PATHOGENESIS OF HEPATOCELLULAR CARCINOMA. CHRONIC HEPATITIS B VIRUS (HBV) INFECTION IS A WORLDWIDE HEALTH PROBLEM. HEPATITIS B VIRUS X PROTEIN (HBX), A PLEIOTROPIC REGULATORY PROTEIN ENCODED BY HBV, IS NECESSARY FOR THE TRANSCRIPTION OF HBV COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) MINICHROMOSOMES, AND AFFECTS THE EPIGENETIC REGULATION OF HOST CELLS. THE EPIGENETIC REPROGRAMMING OF HBX ON HOST CELL GENOME IS STRONGLY INVOLVED IN HBV-RELATED HCC CARCINOGENESIS. HERE, WE REVIEW THE LATEST FINDINGS OF THE EPIGENETIC REGULATION INDUCED BY HBX PROTEIN IN HEPATOCELLULAR CARCINOMA (HCC), INCLUDING DNA METHYLATION, HISTONE MODIFICATION AND NON-CODING RNA EXPRESSION. THE INFLUENCE OF HBX ON THE EPIGENETIC REGULATION OF CCCDNA IS ALSO SUMMARIZED. IN ADDITION, PRELIMINARY STUDIES OF TARGETED DRUGS FOR EPIGENETIC CHANGES INDUCED BY HBX ARE ALSO DISCUSSED. THE EXPLORATION OF EPIGENETIC MARKERS AS POTENTIAL TARGETS WILL HELP TO DEVELOP NEW PREVENTION AND/OR TREATMENT METHODS FOR HBX-RELATED HCC. 2022 10 1700 42 DYNAMIC EXPRESSION OF ZNF382 AND ITS TUMOR-SUPPRESSOR ROLE IN HEPATITIS B VIRUS-RELATED HEPATOCELLULAR CARCINOGENESIS. HEPATITIS B VIRUS (HBV) INFECTION IS THE PRIMARY CAUSE OF HEPATOCELLULAR CARCINOMA (HCC). ZINC-FINGER PROTEIN 382 (ZNF382), WHICH BELONGS TO ZINC-FINGER PROTEIN FAMILY, HAS BEEN DOCUMENTED TO BE DOWNREGULATED IN CERTAIN TYPES OF CANCER. HOWEVER, ITS ROLE IN HCC REMAINS LARGELY UNKNOWN. IN THIS STUDY, WE DEMONSTRATED THAT ZNF382 EXPRESSION WAS SIGNIFICANTLY ELEVATED IN HBV-INFECTED LIVER CIRRHOSIS TISSUES RELATIVE TO HBV-NEGATIVE NORMAL LIVER TISSUES AT PROTEIN LEVELS, BUT NOT AT MRNA LEVELS, AND WAS POSITIVELY CORRELATED WITH THE LEVELS OF HBV DNA AND HEPATITIS B VIRUS X PROTEIN (HBX). FURTHER STUDIES REVEALED THAT ZNF382 WAS A TARGET OF MIR-6867, AND HBX PROMOTED THE TRANSLATION OF ZNF382 DURING HBV CHRONIC INFECTION THROUGH ERK-MEDIATED MIR-6867 INHIBITION. IN ADDITION, OUR DATA SHOWED THAT ZNF382 WAS FREQUENTLY DOWNREGULATED BY PROMOTER METHYLATION IN HBV-RELATED HCCS RELATIVE TO HBV-INFECTED LIVER CIRRHOSIS TISSUES, AND DECREASED EXPRESSION OF ZNF382 WAS STRONGLY CORRELATED WITH POOR SURVIVAL IN EARLY-STAGE HCC PATIENTS. FUNCTIONAL STUDIES DEMONSTRATED THAT ZNF382 WAS A POTENT TUMOR SUPPRESSOR IN HCC CELLS THROUGH INHIBITING CELL PROLIFERATION, COLONY FORMATION, MIGRATION, INVASION, AND TUMORIGENIC POTENTIAL IN NUDE MICE, AND INDUCING CELL APOPTOSIS. MECHANISTICALLY, ZNF382 EXERTED ITS TUMOR-SUPPRESSOR FUNCTIONS IN HCC THROUGH TRANSCRIPTIONALLY REPRESSING ITS DOWNSTREAM TARGETS SUCH AS FOS PROTO-ONCOGENE (FOS), JUN PROTO-ONCOGENE (JUN), DISHEVELED SEGMENT POLARITY PROTEIN 2 (DVL2), AND FRIZZLED CLASS RECEPTOR 1 (FZD1), THEREBY IMPAIRING THE ACTIVITIES OF ACTIVATING PROTEIN 1 (AP-1) AND WNT/BETA-CATENIN PATHWAYS AND ACTIVATING P53 SIGNALING. ALTOGETHER, OUR DATA SHOW THAT ZNF382 ACTS AS A TUMOR SUPPRESSOR, AND IS CO-REGULATED BY HBX AND EPIGENETIC MECHANISM IN HBV-RELATED HEPATOCELLULAR CARCINOGENESIS. 2019 11 6868 31 [PATHOGENESIS OF HEPATITIS B VIRUS-RELATED HEPATOCELLULAR CARCINOMA]. HEPATOCELLULAR CARCINOMA (HCC) IS ONE OF THE MOST COMMON CANCER WORLDWIDE. MOST OF THE HCC OCCUR IN DEVELOPING COUNTRIES. CHRONIC HEPATITIS B VIRUS (HBV) INFECTION IS AN IMPORTANT RISK FACTOR FOR HCC DEVELOPMENT. HBV INDUCES IMMUNE-MEDIATED CHRONIC HEPATITIS, LIVER INJURY, REGENERATION AND SCAR FORMING RESPONSES, LEADING TO AN INFLAMMATORY, FIBROTIC AND IMMUNE DEFICIENT MICROENVIRONMENT. HBV MAY INTEGRATE INTO HOST GENOME, INDUCING GENETIC ABNORMALITY AND ALTERING THE EXPRESSION OF HCC-RELATED GENES. HBV ALSO EXPRESSES ACTIVE PROTEINS SUCH AS X (HBX) AND S PROTEINS, WHICH MAY TRANS-ACTIVATE HCC-RELATED PROTEINS EXPRESSION, INTERACT WITH INTRACELLULAR SPECIFIC PROTEINS, ACTIVATE A VARIETY OF SIGNALING PATHWAYS, AND INDUCE ABERRANT EPIGENETIC MODIFICATIONS. HBV MUTATION ALSO HAS IMPACT ON HBV RELATED HCC DEVELOPMENT. 2016 12 5715 53 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 13 3779 51 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 14 3185 37 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 15 5226 48 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 16 3246 36 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 17 4771 44 NUCLEAR SENSOR INTERFERON-INDUCIBLE PROTEIN 16 INHIBITS THE FUNCTION OF HEPATITIS B VIRUS COVALENTLY CLOSED CIRCULAR DNA BY INTEGRATING INNATE IMMUNE ACTIVATION AND EPIGENETIC SUPPRESSION. BACKGROUND AND AIMS: NUCLEAR-LOCATED COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) OF HEPATITIS B VIRUS (HBV) IS A DETERMINING FACTOR FOR HBV PERSISTENCE AND THE KEY OBSTACLE FOR A CURE OF CHRONIC HEPATITIS B. HOWEVER, IT REMAINS UNCLEAR WHETHER AND HOW THE HOST IMMUNE SYSTEM SENSES HBV CCCDNA AND ITS BIOLOGICAL CONSEQUENCES. APPROACH AND RESULTS: HERE, WE DEMONSTRATED THAT INTERFERON-INDUCIBLE PROTEIN 16 (IFI16) COULD SERVE AS A UNIQUE INNATE SENSOR TO RECOGNIZE AND BIND TO HBV CCCDNA IN HEPATIC NUCLEI, LEADING TO THE INHIBITION OF CCCDNA TRANSCRIPTION AND HBV REPLICATION. MECHANISTICALLY, OUR DATA SHOWED THAT IFI16 PROMOTED THE EPIGENETIC SUPPRESSION OF HBV CCCDNA BY TARGETING AN INTERFERON-STIMULATED RESPONSE ELEMENT (ISRE) PRESENT IN CCCDNA. IT IS OF INTEREST THAT THIS ISRE WAS ALSO REVEALED TO PLAY AN IMPORTANT ROLE IN IFI16-ACTIVATED TYPE I INTERFERON RESPONSES. FURTHERMORE, OUR DATA REVEALED THAT HBV COULD DOWN-REGULATE THE EXPRESSION LEVEL OF IFI16 IN HEPATOCYTES, AND THERE WAS A NEGATIVE CORRELATION BETWEEN IFI16 AND HBV TRANSCRIPTS IN LIVER BIOPSIES, SUGGESTING THE POSSIBLE ROLE OF IFI16 IN SUPPRESSING CCCDNA FUNCTION UNDER PHYSIOLOGICAL CONDITIONS. CONCLUSIONS: THE NUCLEAR SENSOR IFI16 SUPPRESSES CCCDNA FUNCTION BY INTEGRATING INNATE IMMUNE ACTIVATION AND EPIGENETIC REGULATION BY TARGETING THE ISRE OF CCCDNA, AND IFI16 MAY PRESENT AS A THERAPEUTIC TARGET AGAINST HBV INFECTION. 2020 18 5936 38 TARGETING HEPATITIS B VIRUS COVALENTLY CLOSED CIRCULAR DNA AND HEPATITIS B VIRUS X PROTEIN: RECENT ADVANCES AND NEW APPROACHES. CHRONIC HEPATITIS B VIRUS (HBV) INFECTION REMAINS A WORLDWIDE CONCERN AND PUBLIC HEALTH PROBLEM. TWO KEY ASPECTS OF THE HBV LIFE CYCLE ARE ESSENTIAL FOR VIRAL REPLICATION AND THUS THE DEVELOPMENT OF CHRONIC INFECTIONS: THE ESTABLISHMENT OF THE VIRAL MINICHROMOSOME, COVALENTLY CLOSED CIRCULAR (CCC) DNA, WITHIN THE NUCLEUS OF INFECTED HEPATOCYTES AND THE EXPRESSION OF THE REGULATORY HEPATITIS B VIRUS X PROTEIN (HBX). INTERESTINGLY, NUCLEAR HBX REDIRECTS HOST EPIGENETIC MACHINERY TO ACTIVATE CCCDNA TRANSCRIPTION. IN THIS PERSPECTIVE, WE PROVIDE AN OVERVIEW OF RECENT ADVANCES IN UNDERSTANDING THE REGULATION OF CCCDNA AND THE MECHANISTIC AND FUNCTIONAL ROLES OF HBX. WE ALSO DESCRIBE THE PROGRESS TOWARD TARGETING BOTH CCCDNA AND HBX FOR THERAPEUTIC PURPOSES. FINALLY, WE OUTLINE STANDING QUESTIONS IN THE FIELD AND PROPOSE COMPLEMENTARY CHEMICAL BIOLOGY APPROACHES TO ADDRESS THEM. 2019 19 1042 24 CLINICAL AND MOLECULAR BASIS OF HEPATOCELLULAR CARCINOMA AFTER HEPATITIS C VIRUS ERADICATION. HEPATOCELLULAR CARCINOMA (HCC) ARISES IN THE BACKGROUND OF CHRONIC LIVER DISEASES, INCLUDING HEPATITIS AND LIVER CIRRHOSIS CAUSED BY HEPATITIS C VIRUS (HCV) INFECTION. IT IS WELL KNOWN THAT HCV ERADICATION USING ANTIVIRAL DRUGS CAN EFFICIENTLY INHIBIT HEPATOCARCINOGENESIS. RECENT ADVANCES IN AND DEVELOPMENT OF DIRECT-ACTING ANTIVIRAL (DAA) DRUGS HAS REVOLUTIONIZED THE TREATMENT OF HCV INFECTION, AND THE VAST MAJORITY OF HCV PATIENTS CAN ACHIEVE HCV ERADICATION USING DAAS. HOWEVER, MOUNTING EVIDENCE CLEARLY INDICATES THAT HCC INEVITABLY OCCURS IN A SUBSET OF PATIENTS AFTER SUCCESSFUL VIRAL ERADICATION USING DAA THERAPY. CANCER IS A GENETIC DISEASE, AND THE ACCUMULATION OF GENETIC AND EPIGENETIC ABERRATIONS MAY CAUSE HEPATOCARCINOGENESIS IN CHRONICALLY DAMAGED LIVER, EVEN AFTER VIRUS ELIMINATION. IN THIS REVIEW, WE HIGHLIGHT HCC DEVELOPMENT AFTER HCV ERADICATION AND DISCUSS THE CURRENT UNDERSTANDING OF THE MOLECULAR MECHANISMS OF TUMORIGENESIS AFTER VIRUS ELIMINATION, FOCUSING ON THE GENETIC AND EPIGENETIC BACKGROUND OF CHRONICALLY DAMAGED LIVER TISSUES. 2022 20 4454 32 MOLECULAR MECHANISMS DRIVING PROGRESSION OF LIVER CIRRHOSIS TOWARDS HEPATOCELLULAR CARCINOMA IN CHRONIC HEPATITIS B AND C INFECTIONS: A REVIEW. ALMOST ALL PATIENTS WITH HEPATOCELLULAR CARCINOMA (HCC), A MAJOR TYPE OF PRIMARY LIVER CANCER, ALSO HAVE LIVER CIRRHOSIS, THE SEVERITY OF WHICH HAMPERS EFFECTIVE TREATMENT FOR HCC DESPITE RECENT PROGRESS IN THE EFFICACY OF ANTICANCER DRUGS FOR ADVANCED STAGES OF HCC. HERE, WE REVIEW RECENT KNOWLEDGE CONCERNING THE MOLECULAR MECHANISMS OF LIVER CIRRHOSIS AND ITS PROGRESSION TO HCC FROM GENETIC AND EPIGENOMIC POINTS OF VIEW. BECAUSE ~70% OF PATIENTS WITH HCC HAVE HEPATITIS B VIRUS (HBV) AND/OR HEPATITIS C VIRUS (HCV) INFECTION, WE FOCUSED ON HBV- AND HCV-ASSOCIATED HCC. THE LITERATURE SUGGESTS THAT GENETIC AND EPIGENETIC FACTORS, SUCH AS MICRORNAS, PLAY A ROLE IN LIVER CIRRHOSIS AND ITS PROGRESSION TO HCC, AND THAT HBV- AND HCV-ENCODED PROTEINS APPEAR TO BE INVOLVED IN HEPATOCARCINOGENESIS. FURTHER STUDIES ARE NEEDED TO ELUCIDATE THE MECHANISMS, INCLUDING IMMUNE CHECKPOINTS AND MOLECULAR TARGETS OF KINASE INHIBITORS, ASSOCIATED WITH LIVER CIRRHOSIS AND ITS PROGRESSION TO HCC. 2019