1 4815 161 OCCULT HEPATITIS B INFECTION AND HEPATOCELLULAR CARCINOMA: EPIDEMIOLOGY, VIROLOGY, HEPATOCARCINOGENESIS AND CLINICAL SIGNIFICANCE. OCCULT HEPATITIS B INFECTION (OBI) REFERS TO A CONDITION WHERE REPLICATION-COMPETENT HBV DNA IS PRESENT IN THE LIVER, WITH OR WITHOUT HBV DNA IN THE BLOOD, IN INDIVIDUALS WITH SERUM HBSAG NEGATIVITY ASSESSED BY CURRENTLY AVAILABLE ASSAYS. THE EPISOMAL COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) IN OBI IS IN A LOW REPLICATIVE STATE. VIRAL GENE EXPRESSION IS MEDIATED BY EPIGENETIC CONTROL OF HBV TRANSCRIPTION, INCLUDING THE HBV CPG ISLAND METHYLATION PATHWAY AND POST-TRANSLATIONAL MODIFICATION OF CCCDNA-BOUND HISTONE, WITH A DIFFERENT PATTERN FROM PATIENTS WITH CHRONIC HBV INFECTION. THE PREVALENCE OF OBI VARIES TREMENDOUSLY ACROSS PATIENT POPULATIONS OWING TO NUMEROUS FACTORS, SUCH AS GEOGRAPHIC LOCATION, ASSAY CHARACTERISTICS, HOST IMMUNE RESPONSE, COINFECTION WITH OTHER VIRUSES, AND VACCINATION STATUS. APART FROM THE RISK OF VIRAL REACTIVATION UPON IMMUNOSUPPRESSION AND THE RISK OF TRANSMISSION OF HBV, OBI HAS BEEN IMPLICATED IN HEPATOCELLULAR CARCINOMA (HCC) DEVELOPMENT IN PATIENTS WITH CHRONIC HCV INFECTION, THOSE WITH CRYPTOGENIC OR KNOWN LIVER DISEASE, AND IN PATIENTS WITH HBSAG SEROCLEARANCE AFTER CHRONIC HBV INFECTION. AN INCREASING NUMBER OF PROSPECTIVE STUDIES AND META-ANALYSES HAVE REPORTED A HIGHER INCIDENCE OF HCC IN PATIENTS WITH HCV AND OBI, AS WELL AS MORE ADVANCED TUMOUR HISTOLOGICAL GRADES AND EARLIER AGE OF HCC DIAGNOSIS, COMPARED WITH PATIENTS WITHOUT OBI. THE PROPOSED PATHOGENETIC MECHANISMS OF OBI-RELATED HCC INCLUDE THE INFLUENCE OF HBV DNA INTEGRATION ON THE HEPATOCYTE CELL CYCLE, THE PRODUCTION OF PRO-ONCOGENIC PROTEINS (HBX PROTEIN AND MUTATED SURFACE PROTEINS), AND PERSISTENT LOW-GRADE NECROINFLAMMATION (CONTRIBUTING TO THE DEVELOPMENT OF FIBROSIS AND CIRRHOSIS). THERE REMAIN UNCERTAINTIES ABOUT EXACTLY HOW, AND IN WHAT ORDER, THESE MECHANISMS DRIVE THE DEVELOPMENT OF TUMOURS IN PATIENTS WITH OBI. 2020 2 4816 54 OCCULT HEPATITIS B VIRUS INFECTION: A COMPLEX ENTITY WITH RELEVANT CLINICAL IMPLICATIONS. OCCULT HEPATITIS B VIRUS (HBV) INFECTION IS A WORLD-WIDE ENTITY, FOLLOWING THE GEOGRAPHICAL DISTRIBUTION OF DETECTABLE HEPATITIS B. THIS ENTITY IS DEFINED AS THE PERSISTENCE OF VIRAL GENOMES IN THE LIVER TISSUE AND IN SOME INSTANCES ALSO IN THE SERUM, ASSOCIATED TO NEGATIVE HBV SURFACE ANTIGEN SEROLOGY. THE MOLECULAR BASIS OF THE OCCULT INFECTION IS RELATED TO THE LIFE CYCLE OF HBV, WHICH PRODUCES A COVALENTLY CLOSED CIRCULAR DNA THAT PERSISTS IN THE CELL NUCLEI AS AN EPISOME, AND SERVES AS A TEMPLATE FOR GENE TRANSCRIPTION. THE MECHANISM RESPONSIBLE FOR THE HBSAG NEGATIVE STATUS IN OCCULT HBV CARRIERS IS A STRONG SUPPRESSION OF VIRAL REPLICATION, PROBABLY DUE TO THE HOST'S IMMUNE RESPONSE, CO-INFECTION WITH OTHER INFECTIOUS AGENTS AND EPIGENETIC FACTORS. THERE IS EMERGING EVIDENCE OF THE POTENTIAL CLINICAL RELEVANCE OF OCCULT HBV INFECTION, SINCE THIS COULD BE INVOLVED IN OCCULT HBV TRANSMISSION THROUGH ORTHOTOPIC LIVER TRANSPLANT AND BLOOD TRANSFUSION, REACTIVATION OF HBV INFECTION DURING IMMUNOSUPPRESSION, IMPAIRING CHRONIC LIVER DISEASE OUTCOME AND ACTING AS A RISK FACTOR FOR HEPATOCELLULAR CARCINOMA. THEREFORE IT IS IMPORTANT TO BEAR IN MIND THIS ENTITY IN CRYPTOGENETIC LIVER DISEASES, HEPATITIS C VIRUS/HIV INFECTED PATIENTS AND IMMUNOSUPRESSED INDIVIDUALS. IT IS ALSO NECESSARY TO INCREASE OUR KNOWLEDGE IN THIS FASCINATING FIELD TO DEFINE BETTER STRATEGIES TO DIAGNOSE AND TREAT THIS INFECTION. 2011 3 4817 64 OCCULT HEPATITIS B VIRUS INFECTION: AN UPDATE. OCCULT HEPATITIS B VIRUS (HBV) INFECTION (OBI) REFERS TO A CONDITION IN WHICH REPLICATION-COMPETENT VIRAL DNA IS PRESENT IN THE LIVER (WITH DETECTABLE OR UNDETECTABLE HBV DNA IN THE SERUM) OF INDIVIDUALS TESTING NEGATIVE FOR THE HBV SURFACE ANTIGEN (HBSAG). IN THIS PECULIAR PHASE OF HBV INFECTION, THE COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) IS IN A LOW STATE OF REPLICATION. MANY ADVANCES HAVE BEEN MADE IN CLARIFYING THE MECHANISMS INVOLVED IN SUCH A SUPPRESSION OF VIRAL ACTIVITY, WHICH SEEMS TO BE MAINLY RELATED TO THE HOST'S IMMUNE CONTROL AND EPIGENETIC FACTORS. OBI IS DIFFUSED WORLDWIDE, BUT ITS PREVALENCE IS HIGHLY VARIABLE AMONG PATIENT POPULATIONS. THIS DEPENDS ON DIFFERENT GEOGRAPHIC AREAS, RISK FACTORS FOR PARENTERAL INFECTIONS, AND ASSAYS USED FOR HBSAG AND HBV DNA DETECTION. OBI HAS AN IMPACT IN SEVERAL CLINICAL CONTEXTS: (A) IT CAN BE TRANSMITTED, CAUSING A CLASSIC FORM OF HEPATITIS B, THROUGH BLOOD TRANSFUSION OR LIVER TRANSPLANTATION; (B) IT MAY REACTIVATE IN THE CASE OF IMMUNOSUPPRESSION, LEADING TO THE POSSIBLE DEVELOPMENT OF EVEN FULMINANT HEPATITIS; (C) IT MAY ACCELERATE THE PROGRESSION OF CHRONIC LIVER DISEASE DUE TO DIFFERENT CAUSES TOWARD CIRRHOSIS; (D) IT MAINTAINS THE PRO-ONCOGENIC PROPERTIES OF THE "OVERT" INFECTION, FAVORING THE DEVELOPMENT OF HEPATOCELLULAR CARCINOMA. 2022 4 442 33 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 5 3185 34 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 6 6862 54 [OCCULT HEPATITIS B VIRUS INFECTION]. OCCULT HEPATITIS B VIRUS (HBV) INFECTION IS A PECULIAR FORM OF CHRONIC VIRAL INFECTION IDENTIFIED SINCE THE EARLY 80'S AND CAN BE DEFINED AS THE PRESENCE OF HBV DNA IN THE SERUM AND/OR IN THE LIVER TISSUE OF PATIENTS NEGATIVE FOR THE HBV SURFACE ANTIGEN (HBSAG) USING USUAL SEROLOGICAL TESTS. THE DATA ABOUT THE PREVALENCE OF OCCULT HBV INFECTION ARE CONTRASTING AND THE REPORTED PREVALENCES IN VARIOUS CATEGORIES OF INDIVIDUALS ARE HIGHLY DIVERSE. THE MOLECULAR BASIS OF THE OCCULT HBV INFECTION IS THE COVALENTLY CLOSED-CIRCULAR DNA (CCCDNA) THAT PERSISTS IN THE CELL NUCLEI AND THAT SERVES AS A TEMPLATE FOR GENE TRANSCRIPTION. THE PHYSIOPATHOLOGY OF OCCULT HBV INFECTION IS STILL UNCLEAR. HOWEVER, THE AVAILABLE DATA SUGGEST THAT THE HOST'S IMMUNE RESPONSE, THE CO-INFECTIONS WITH OTHER INFECTIOUS AGENTS AND EPIGENETIC FACTORS MAY PLAY IMPORTANT ROLES IN INDICING THE OCCULT STATUS. THE CLINICAL RELEVANCE OF OCCULTHBVINFECTION REMAINS DEBATED BUT IT MAY IMPACT IN FOUR CLINICAL CONTEXTS: 1) THE TRANSMISSION OF THE INFECTION BY BLOOD TRANSFUSION OR ORGAN TRANSPLANTATION; 2) THE ACUTE REACTIVATION WHEN AN IMMUNOSUPPRESSIVE STATUS OCCURS MAINLY IN PATIENTS WITH ISOLATED ANTI-HBC (CHEMOTHERAPY, TRANSPLANTATIONS, IMMUNODEPRESSION, NEW IMMUNOSUPPRESSIVE THERAPY AS ANTI-CD20 OR ANTI TNF); 3) THE POTENT BUT NON PROVED PROGRESSION OF LIVER FIBROSIS IN HCV INFECTED PATIENTS OR IN PATIENTS WITH CRYPTOGENETIC LIVER DISEASE; AND, 4. THE RISK FACTOR FOR HEPATOCELLULAR CARCINOMA DEVELOPMENT. 2008 7 5368 32 RECENT ADVANCES IN THE STUDY OF HEPATITIS B VIRUS COVALENTLY CLOSED CIRCULAR DNA. CHRONIC HEPATITIS B INFECTION IS CAUSED BY HEPATITIS B VIRUS (HBV) AND A TOTAL CURE IS YET TO BE ACHIEVED. THE VIRAL COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) IS THE KEY TO ESTABLISH A PERSISTENT INFECTION WITHIN HEPATOCYTES. CURRENT ANTIVIRAL STRATEGIES HAVE NO EFFECT ON THE PRE-EXISTING CCCDNA RESERVOIR. THEREFORE, THE STUDY OF THE MOLECULAR MECHANISM OF CCCDNA FORMATION IS BECOMING A MAJOR FOCUS OF HBV RESEARCH. THIS REVIEW SUMMARIZES THE CURRENT ADVANCES IN CCCDNA MOLECULAR BIOLOGY AND THE LATEST STUDIES ON THE ELIMINATION OR INACTIVATION OF CCCDNA, INCLUDING THREE MAJOR AREAS: (1) EPIGENETIC REGULATION OF CCCDNA BY HBV X PROTEIN, (2) IMMUNE-MEDIATED DEGRADATION, AND (3) GENOME-EDITING NUCLEASES. ALL THESE ASPECTS PROVIDE CLUES ON HOW TO FINALLY ATTAIN A CURE FOR CHRONIC HEPATITIS B INFECTION. 2017 8 3782 43 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 9 1190 34 CORRELATION BETWEEN HEPATIC HUMAN MALES ABSENT ON THE FIRST (HMOF) AND VIRAL PERSISTENCE IN CHRONIC HEPATITIS B PATIENTS. BACKGROUND: CHRONIC HEPATITIS B (CHB) REMAINS A GLOBAL HEALTH DILEMMA WITH HIGH MORBIDITY AND MORTALITY. HUMAN MALES ABSENT ON THE FIRST (HMOF) (A HISTONE ACETYLTRANSFERASE) IS RESPONSIBLE FOR DNA DAMAGE REPAIR, TUMORIGENESIS AND CELL CYCLE REGULATION. PERSISTENCE OF HBV DNA CONTRIBUTES TO CIRRHOSIS AND HEPATOCELLULAR CARCINOMA (HCC) IN CHB PATIENTS. HISTONE ACETYLTRANSFERASE ENHANCES HBV REPLICATION, HOWEVER THE PRECISE UNDERLYING MECHANISM OF HMOF IN HBV REPLICATION IN CHB PATIENTS REMAINS TO BE EXPLORED. THIS STUDY AIMS TO INVESTIGATE THE CORRELATION BETWEEN HEPATIC HMOF AND HBV DNA REPLICATION IN CHB PATIENTS, AND MAY PROVIDE NEW INSIGHTS TOWARDS THE TREATMENT OF CHB PATIENTS. METHODS: HMOF IN LIVER BIOPSY (CHB, N = 33 HBEAG(+); N = 20 HBEAG(-), AND THREE HEALTHY CONTROLS) WAS DETERMINED, USING IMMUNOHISTOCHEMISTRY, QPCR AND WESTERN BLOT. THE CORRELATION BETWEEN HMOF AND HBSAG, AS WELL AS, HBEAG WERE DETERMINED. RESULTS: A POSITIVE CORRELATION BETWEEN HMOF AND HBV DNA IN OVERALL CHB PATIENTS WAS OBSERVED. A DISTINCT POSITIVE CORRELATION BETWEEN HMOF AND HBSAG AND/OR HBEAG IN HBEAG(+) CHB PATIENTS WAS ALSO DETECTED, HOWEVER NOT OBSERVED BETWEEN HMOF AND HBSAG IN HBEAG(-) CHB PATIENTS. NO CORRELATION WAS OBSERVED BETWEEN HMOF AND HEPATIC INFLAMMATION SEVERITY AND FIBROTIC STAGE IN CHB PATIENTS. CONCLUSIONS: HEPATIC HMOF MIGHT CONTRIBUTE TO HOST HBV CLEARANCE IN CHB PATIENTS AND POSSIBLE PATHOGENESIS. 2018 10 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 11 5936 30 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 12 1134 42 COMPREHENSIVE GENETIC AND EPIGENETIC ANALYSIS OF OCCULT HEPATITIS B FROM LIVER TISSUE SAMPLES. BACKGROUND: OCCULT INFECTION WITH HEPATITIS B VIRUS (HBV) IS A TYPE OF CHRONIC HBV INFECTION THAT IS CHARACTERIZED BY THE ABSENCE OF A DETECTABLE HEPATITIS B SURFACE ANTIGEN IN THE BLOOD AND BY VERY LOW LEVELS OF HBV DNA IN THE BLOOD AND LIVER. THE MECHANISMS LEADING TO OCCULT HBV INFECTION REMAIN POORLY UNDERSTOOD BUT INCLUDE POSSIBLE GENETIC MUTATIONS AND DELETIONS. RECENTLY, IT HAS BEEN SHOWN THAT HBV HAS CPG ISLANDS THAT ARE METHYLATED, RAISING THE POSSIBILITY THAT EPIGENETIC CHANGES MAY ALSO BE IMPORTANT. METHODS: THE FULL-LENGTH GENOMES OF ISOLATES FROM 5 CASES OF OCCULT HBV INFECTION WERE CLONED AND ANALYZED FOR MUTATIONS AND DELETIONS. ADDITIONAL STUDIES WERE PERFORMED TO EXAMINE FOR APOBEC3G (1 MEMBER OF A FAMILY OF DEAMINATING PROTEINS THAT ARE PART OF THE INNATE IMMUNE SYSTEM'S DEFENSE AGAINST VIRAL INFECTION) HYPEREDITING AND METHYLATION OF VIRAL DNA. RESULTS: NUMEROUS MUTATIONS AND DELETIONS WERE FOUND IN THE GENOMES OF OCCULT HBV. HOWEVER, SIMILAR TYPES AND LOCATIONS OF POLYMORPHISMS WERE ALSO NOTED IN THE GENOME SEQUENCES OF HBV ISOLATED FROM CONTROL LIVER TISSUE SAMPLES OBTAINED FROM INDIVIDUALS WITH NONOCCULT HBV INFECTION. EVIDENCE OF APOBEC3G HYPEREDITING WAS FOUND IN 1 CASE OF OCCULT HBV INFECTION, BUT HYPEREDITED SEQUENCES MADE UP ONLY A SMALL PROPORTION OF THE VIRAL SEQUENCES. METHYLATION OF HBV CPG ISLANDS 1 AND 2 WAS EVIDENT IN BOTH OCCULT AND NONOCCULT HBV SEQUENCES, WITH ISLAND 2 MORE DENSELY METHYLATED IN OCCULT HBV SEQUENCES AND ISLAND 1 MORE DENSELY METHYLATED IN NONOCCULT HBV SEQUENCES. CONCLUSION: DELETIONS AND MUTATIONS ARE COMMON IN OCCULT HBV BUT ARE ALSO FOUND IN CONTROL NONOCCULT HBV, AND NO UNIQUE GENETIC SIGNATURE FOR OCCULT HBV WAS FOUND. METHYLATION PATTERNS DIFFER BETWEEN CASES OF OCCULT AND NONOCCULT HBV INFECTION, SUGGESTING THAT EPIGENETIC CHANGES MAY BE RELEVANT TO OCCULT HBV. TOGETHER, THESE FINDINGS SUGGEST THAT MULTIPLE MECHANISMS CAN CONTRIBUTE TO OCCULT HBV INFECTION. 2008 13 3246 29 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 14 5689 49 SILENCING HEPATITIS B VIRUS COVALENTLY CLOSED CIRCULAR DNA: THE POTENTIAL OF AN EPIGENETIC THERAPY APPROACH. GLOBAL PROPHYLACTIC VACCINATION PROGRAMMES HAVE HELPED TO CURB NEW HEPATITIS B VIRUS (HBV) INFECTIONS. HOWEVER, IT IS ESTIMATED THAT NEARLY 300 MILLION PEOPLE ARE CHRONICALLY INFECTED AND HAVE A HIGH RISK OF DEVELOPING HEPATOCELLULAR CARCINOMA. AS SUCH, HBV REMAINS A SERIOUS HEALTH PRIORITY AND THE DEVELOPMENT OF NOVEL CURATIVE THERAPEUTICS IS URGENTLY NEEDED. CHRONIC HBV INFECTION HAS BEEN ATTRIBUTED TO THE PERSISTENCE OF THE COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) WHICH ESTABLISHES ITSELF AS A MINICHROMOSOME IN THE NUCLEUS OF HEPATOCYTES. AS THE VIRAL TRANSCRIPTION INTERMEDIATE, THE CCCDNA IS RESPONSIBLE FOR PRODUCING NEW VIRIONS AND PERPETUATING INFECTION. HBV IS DEPENDENT ON VARIOUS HOST FACTORS FOR CCCDNA FORMATION AND THE MINICHROMOSOME IS AMENABLE TO EPIGENETIC MODIFICATIONS. TWO HBV PROTEINS, X (HBX) AND CORE (HBC) PROMOTE VIRAL REPLICATION BY MODULATING THE CCCDNA EPIGENOME AND REGULATING HOST CELL RESPONSES. THIS INCLUDES VIRAL AND HOST GENE EXPRESSION, CHROMATIN REMODELING, DNA METHYLATION, THE ANTIVIRAL IMMUNE RESPONSE, APOPTOSIS, AND UBIQUITINATION. ELIMINATION OF THE CCCDNA MINICHROMOSOME WOULD RESULT IN A STERILIZING CURE; HOWEVER, THIS MAY BE DIFFICULT TO ACHIEVE. EPIGENETIC THERAPIES COULD PERMANENTLY SILENCE THE CCCDNA MINICHROMOSOME AND PROMOTE A FUNCTIONAL CURE. THIS REVIEW EXPLORES THE CCCDNA EPIGENOME, HOW HOST AND VIRAL FACTORS INFLUENCE TRANSCRIPTION, AND THE RECENT EPIGENETIC THERAPIES AND EPIGENOME ENGINEERING APPROACHES THAT HAVE BEEN DESCRIBED. 2021 15 3186 44 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 16 1042 30 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 17 3794 42 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 18 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 19 5365 29 RECENT ADVANCES IN HEPATITIS B TREATMENT. HEPATITIS B VIRUS INFECTION AFFECTS OVER 250 MILLION CHRONIC CARRIERS, CAUSING MORE THAN 800,000 DEATHS ANNUALLY, ALTHOUGH A SAFE AND EFFECTIVE VACCINE IS AVAILABLE. CURRENTLY USED ANTIVIRAL AGENTS, PEGYLATED INTERFERON AND NUCLEOS(T)IDE ANALOGUES, HAVE MAJOR DRAWBACKS AND FAIL TO COMPLETELY ERADICATE THE VIRUS FROM INFECTED CELLS. THUS, ACHIEVING A "FUNCTIONAL CURE" OF THE INFECTION REMAINS A REAL CHALLENGE. RECENT FINDINGS CONCERNING THE VIRAL REPLICATION CYCLE HAVE LED TO DEVELOPMENT OF NOVEL THERAPEUTIC APPROACHES INCLUDING VIRAL ENTRY INHIBITORS, EPIGENETIC CONTROL OF CCCDNA, IMMUNE MODULATORS, RNA INTERFERENCE TECHNIQUES, RIBONUCLEASE H INHIBITORS, AND CAPSID ASSEMBLY MODULATORS. PROMISING PRECLINICAL RESULTS HAVE BEEN OBTAINED, AND THE LEADING MOLECULES UNDER DEVELOPMENT HAVE ENTERED CLINICAL EVALUATION. THIS REVIEW SUMMARIZES THE KEY STEPS OF THE HBV LIFE CYCLE, EXAMINES THE CURRENTLY APPROVED ANTI-HBV DRUGS, AND ANALYZES NOVEL HBV TREATMENT REGIMENS. 2021 20 6868 34 [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