1 3247 133 HEPATITIS B VIRUS BASAL CORE PROMOTER MUTATIONS SHOW LOWER REPLICATION FITNESS ASSOCIATED WITH CCCDNA ACETYLATION STATUS. IN CHRONIC HEPATITIS B VIRUS (HBV) INFECTION, VARIANTS WITH MUTATIONS IN THE BASAL CORE PROMOTER (BCP) AND PRECORE REGION PREDOMINATE AND ASSOCIATE WITH MORE SEVERE DISEASE FORMS. STUDIES ON THEIR EFFECT ON VIRAL REPLICATION REMAIN CONTROVERSIAL. INCREASING EVIDENCE SHOWS THAT EPIGENETIC MODIFICATIONS OF CCCDNA REGULATE HBV REPLICATION AND DISEASE OUTCOME. HERE WE DETERMINED THE TRANSCRIPTION AND VIRAL REPLICATION EFFICIENCY OF WELL-DEFINED BCP AND PRECORE MUTATIONS AND THEIR EFFECT ON CCCDNA EPIGENETIC CONTROL. HBV MONOMERS BEARING BCP MUTATIONS A1762T/G1764A AND A1762T/G1764A/C1766T, AND PRECORE MUTATIONS G1896A, G1899A AND G1896A/G1899A, WERE TRANSFECTED INTO HEPG2 CELLS USING A PLASMID-FREE APPROACH. VIRAL RNA TRANSCRIPTS WERE DETECTED BY NORTHERN BLOT HYBRIDIZATION AND RT PCR, DNA REPLICATIVE INTERMEDIATES BY SOUTHERN BLOTTING AND RT PCR, AND VIRAL RELEASE WAS MEASURED BY ELISA. ACETYLATION OF CCCDNA-BOUND HISTONES WAS ASSESSED BY CHROMATIN IMMUNOPRECIPITATION (CHIP) ASSAY AND METHYLATION OF CCCDNA BY BISULFITE SEQUENCING. BCP MUTATIONS RESULTED IN LOW VIRAL RELEASE, MRNA TRANSCRIPTION AND PGRNA/CCCDNA RATIOS THAT PARALLELED THE ACETYLATION OF CCCDNA-BOUND H4 HISTONE AND INVERSELY CORRELATED WITH THE HDAC1 RECRUITMENT ONTO CCCDNA. INDEPENDENTLY OF THE MUTATIONS, CCCDNA WAS A TARGET FOR METHYLATION, ACCOMPANIED BY THE UPREGULATION OF DNMT1 EXPRESSION AND DNMT1 RECRUITMENT ONTO CCCDNA. OUR RESULTS SUGGEST THAT BCP MUTATIONS DECREASE VIRAL REPLICATION CAPACITY POSSIBLY BY MODULATING THE ACETYLATION AND DEACETYLATION OF CCCDNA-BOUND HISTONES WHILE PRECORE MUTATIONS DO NOT HAVE A SIGNIFICANT EFFECT ON VIRAL REPLICATION. THESE DATA PROVIDE EVIDENCE THAT EPIGENETIC FACTORS CONTRIBUTE TO THE REGULATION OF HBV VIRAL REPLICATION. 2016 2 5678 46 SHORT HAIRPIN RNA INDUCES METHYLATION OF HEPATITIS B VIRUS COVALENTLY CLOSED CIRCULAR DNA IN HUMAN HEPATOMA CELLS. SMALL INTERFERING RNAS NOT ONLY MODULATE GENE EXPRESSION AT A POST-TRANSCRIPTIONAL LEVEL, BUT ALSO INDUCE TRANSCRIPTIONAL GENE SILENCING BY RNA INTERFERENCE-MEDIATED HETEROCHROMATIN FORMATION AND RNA-DIRECTED DNA METHYLATION (RDDM). HOWEVER, ALTHOUGH ESTABLISHED IN PLANTS, THERE HAVE BEEN CONTROVERSIES WHETHER RDDM OPERATES IN MAMMALS. HEPATITIS B VIRUS (HBV) COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) SERVES AS A TEMPLATE FOR VIRAL RNA TRANSCRIPTION, AND TRANSCRIPTIONAL ACTIVITY OF HBV CCCDNA IS REGULATED BY METHYLATION IN PATIENTS WITH CHRONIC HBV INFECTION. IN THIS STUDY, WE STABLY EXPRESSED SHORT HAIRPIN RNA (SHRNA) AGAINST HBV IN HUMAN HEPATOMA CELLS TO DETERMINE WHETHER SHRNA INDUCES METHYLATION OF HBV CCCDNA. HEPAD38 CELLS WHICH PERMIT REPLICATION OF HBV UNDER CONTROL OF TETRACYCLINE-RESPONSIVE PROMOTER WERE TRANSDUCED WITH LENTIVIRAL VECTORS WHICH ENCODE SH-1580, A SHRNA AGAINST THE HEPATITIS B VIRAL PROTEIN HBX. BISULFITE SEQUENCING PCR ANALYSIS REVEALED THAT SH-1580 INDUCED CPG METHYLATIONS AT A HIGHER RATE COMPARED TO CONTROL (31.3% VS. 12.8%, P<0.05). THE SH-1580-INDUCED CPG METHYLATION WAS LOCALIZED NEAR THE TARGET SEQUENCE OF SH-1580 IN MORE THAN A HALF OF THE CLONES. METHYLATION-INDUCED TRANSCRIPTIONAL SUPPRESSION WAS CONFIRMED BY IN VITRO TRANSCRIPTION ASSAY. THESE RESULTS CONFIRM THE FEASIBILITY OF RDDM OF HBV CCCDNA IN HUMAN CELLS. LENTIVIRAL VECTOR-MEDIATED TRANSFER OF SHRNA MAY BE USED AS A TOOL FOR NOVEL TRANSCRIPTIONAL MODULATION BY EPIGENETIC MODIFICATION OF HBV CCCDNA. 2013 3 2837 40 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 4 3728 36 INHIBITION OF REPLICATION OF HEPATITIS B VIRUS USING TRANSCRIPTIONAL REPRESSORS THAT TARGET THE VIRAL DNA. BACKGROUND: CHRONIC INFECTION WITH HEPATITIS B VIRUS (HBV) IS A SERIOUS GLOBAL HEALTH PROBLEM. PERSISTENCE OF THE VIRUS OCCURS AS A RESULT OF STABILITY OF THE REPLICATION INTERMEDIATE COMPRISING COVALENTLY CLOSED CIRCULAR DNA (CCCDNA). DEVELOPMENT OF DRUGS THAT ARE CAPABLE OF DISABLING THIS CCCDNA IS VITAL. METHODS: TO INVESTIGATE AN EPIGENETIC APPROACH TO INACTIVATING VIRAL DNA, WE ENGINEERED TRANSCRIPTIONAL REPRESSORS THAT COMPRISE AN HBV DNA-BINDING DOMAIN OF TRANSCRIPTION ACTIVATOR LIKE EFFECTORS (TALES) AND A FUSED KRUPPEL ASSOCIATED BOX (KRAB). THESE REPRESSOR TALES (RTALES) TARGETED THE VIRAL SURFACE OPEN READING FRAME AND WERE PLACED UNDER TRANSCRIPTION CONTROL OF CONSTITUTIVELY ACTIVE OR LIVER-SPECIFIC PROMOTERS. RESULTS: EVALUATION IN CULTURED CELLS AND FOLLOWING HYDRODYNAMIC INJECTION OF MICE REVEALED THAT THE RTALES SIGNIFICANTLY INHIBITED PRODUCTION OF MARKERS OF HBV REPLICATION WITHOUT EVIDENCE OF HEPATOTOXICITY. INCREASED METHYLATION OF HBV DNA AT CPG ISLAND II SHOWED THAT THE RTALES CAUSED INTENDED EPIGENETIC MODIFICATION. CONCLUSIONS: EPIGENETIC MODIFICATION OF HBV DNA IS A NEW AND EFFECTIVE MEANS OF INACTIVATING THE VIRUS IN VIVO. THE APPROACH HAS THERAPEUTIC POTENTIAL AND AVOIDS POTENTIALLY PROBLEMATIC UNINTENDED MUTAGENESIS OF GENE EDITING. 2019 5 4771 34 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 6 6448 36 THERAPEUTIC SHUTDOWN OF HBV TRANSCRIPTS PROMOTES REAPPEARANCE OF THE SMC5/6 COMPLEX AND SILENCING OF THE VIRAL GENOME IN VIVO. OBJECTIVE: THERAPEUTIC STRATEGIES SILENCING AND REDUCING THE HEPATITIS B VIRUS (HBV) RESERVOIR, THE COVALENTLY CLOSED CIRCULAR DNA (CCCDNA), HAVE THE POTENTIAL TO CURE CHRONIC HBV INFECTION. WE AIMED TO INVESTIGATE THE IMPACT OF SMALL INTERFERRING RNA (SIRNA) TARGETING ALL HBV TRANSCRIPTS OR PEGYLATED INTERFERON-ALPHA (PEG-IFNALPHA) ON THE VIRAL REGULATORY HBX PROTEIN AND THE STRUCTURAL MAINTENANCE OF CHROMOSOME 5/6 COMPLEX (SMC5/6), A HOST FACTOR SUPPRESSING CCCDNA TRANSCRIPTION. IN PARTICULAR, WE ASSESSED WHETHER INTERVENTIONS LOWERING HBV TRANSCRIPTS CAN ACHIEVE AND MAINTAIN SILENCING OF CCCDNA TRANSCRIPTION IN VIVO. DESIGN: HBV-INFECTED HUMAN LIVER CHIMERIC MICE WERE TREATED WITH SIRNA OR PEG-IFNALPHA. VIROLOGICAL AND HOST CHANGES WERE ANALYSED AT THE END OF TREATMENT AND DURING THE REBOUND PHASE BY QUALITATIVE PCR, ELISA, IMMUNOBLOTTING AND CHROMATIN IMMUNOPRECIPITATION. RNA IN SITU HYBRIDISATION WAS COMBINED WITH IMMUNOFLUORESCENCE TO DETECT SMC6 AND HBV RNAS AT SINGLE CELL LEVEL. THE ENTRY INHIBITOR MYRCLUDEX-B WAS USED DURING THE REBOUND PHASE TO AVOID NEW INFECTION EVENTS. RESULTS: BOTH SIRNA AND PEG-IFNALPHA STRONGLY REDUCED ALL HBV MARKERS, INCLUDING HBX LEVELS, THUS ENABLING THE REAPPEARANCE OF SMC5/6 IN HEPATOCYTES THAT ACHIEVED HBV-RNA NEGATIVISATION AND SMC5/6 ASSOCIATION WITH THE CCCDNA. ONLY IFN REDUCED CCCDNA LOADS AND ENHANCED IFN-STIMULATED GENES. HOWEVER, THE ANTIVIRAL EFFECTS DID NOT PERSIST OFF TREATMENT AND SMC5/6 WAS AGAIN DEGRADED. REMARKABLY, THE BLOCKADE OF VIRAL ENTRY THAT STARTED AT THE END OF TREATMENT HINDERED RENEWED DEGRADATION OF SMC5/6. CONCLUSION: THESE RESULTS REVEAL THAT THERAPEUTICS ABROGATING ALL HBV TRANSCRIPTS INCLUDING HBX PROMOTE EPIGENETIC SUPPRESSION OF THE HBV MINICHROMOSOME, WHEREAS STRATEGIES PROTECTING THE HUMAN HEPATOCYTES FROM REINFECTION ARE NEEDED TO MAINTAIN CCCDNA SILENCING. 2022 7 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 8 5335 32 QUANTIFICATION AND EPIGENETIC EVALUATION OF THE RESIDUAL POOL OF HEPATITIS B COVALENTLY CLOSED CIRCULAR DNA IN LONG-TERM NUCLEOSIDE ANALOGUE-TREATED PATIENTS. HEPATITIS B VIRUS (HBV) COVALENTLY CLOSED CIRCULAR (CCC)DNA IS THE KEY GENOMIC FORM RESPONSIBLE FOR VIRAL PERSISTENCE AND VIROLOGICAL RELAPSE AFTER TREATMENT WITHDRAWAL. THE ASSESSMENT OF RESIDUAL INTRAHEPATIC CCCDNA LEVELS AND ACTIVITY AFTER LONG-TERM NUCLEOS(T)IDE ANALOGUES THERAPY STILL REPRESENTS A TECHNICAL CHALLENGE. QUANTITATIVE (Q)PCR, ROLLING CIRCLE AMPLIFICATION (RCA) AND DROPLET DIGITAL (DD)PCR ASSAYS WERE USED TO QUANTIFY RESIDUAL INTRAHEPATIC CCCDNA IN LIVER BIOPSIES FROM 56 CHRONICALLY HBV INFECTED PATIENTS AFTER 3 TO 5 YEARS OF TELBIVUDINE TREATMENT. ACTIVITY OF RESIDUAL CCCDNA WAS EVALUATED BY QUANTIFYING 3.5 KB HBV RNA (PREC/PGRNA) AND BY ASSESSING CCCDNA-ASSOCIATED HISTONE TAILS POST-TRANSCRIPTIONAL MODIFICATIONS (PTMS) BY MICRO-CHROMATIN IMMUNOPRECIPITATION. LONG-TERM TELBIVUDINE TREATMENT RESULTED IN SERUM HBV DNA SUPPRESSION, WITH MOST OF THE PATIENTS REACHING UNDETECTABLE LEVELS. DESPITE 38 OUT OF 56 PATIENTS HAD UNDETECTABLE CCCDNA WHEN ASSESSED BY QPCR, RCA AND DDPCR ASSAYS DETECTED CCCDNA IN ALL-BUT-ONE NEGATIVE SAMPLES. LOW PREC/PGRNA LEVEL IN TELBIVUDINE-TREATED SAMPLES WAS ASSOCIATED WITH ENRICHMENT FOR CCCDNA HISTONE PTMS RELATED TO REPRESSED TRANSCRIPTION. NO DIFFERENCE IN CCCDNA LEVELS WAS FOUND ACCORDING TO SERUM VIRAL MARKERS EVOLUTION. THIS PANEL OF CCCDNA EVALUATION TECHNIQUES SHOULD PROVIDE AN ADDED VALUE FOR THE NEW PROOF-OF-CONCEPT CLINICAL TRIALS AIMING AT A FUNCTIONAL CURE OF CHRONIC HEPATITIS B. 2020 9 3948 36 LNCRNA-CD160 DECREASES THE IMMUNITY OF CD8(+) T CELLS THROUGH EPIGENETIC MECHANISMS IN HEPATITIS B VIRUS INFECTION. THE TRANSFER AND DEVELOPMENT OF CHRONIC HEPATITIS B VIRUS (HBV) INFECTION IS ASSOCIATED WITH THE T CELL IMMUNE RESPONSE, THEREFORE INVESTIGATING THE KEY REGULATORS OF CELL IMMUNE RESPONSE IS NEEDED TO IMPROVE CHRONIC HBV TREATMENT. BLOOD SAMPLES FROM PATIENTS WITH CHRONIC HBV INFECTION WERE USED TO CONFIRM THE CORRELATION BETWEEN HBV INFECTION STAGE AND CD160 RECEPTOR EXPRESSION LEVELS IN CD8(+) T CELLS, THE CD8(+) T CELLS ARE USED TO RESEARCH THE MECHANISM OF T CELL IMMUNE RESPONSE MODULATION, MOREOVER, C3H/HEN MICE WITH REDUCED CD160 EXPRESSION LEVELS WERE USED TO INVESTIGATE THE ASSOCIATION BETWEEN LONG NON-CODING (LNC)RNA-CD160 AND HBV INFECTION. LONG NON-CODING (LNC)RNA-CD160 AND HISTONE-MODIFICATION ENZYME GENE HISTONE DEACETYLASE 11 (HDAC11) EXPRESSION LEVELS WERE NEGATIVELY ASSOCIATED WITH CD160 EXPRESSION. LNCRNA-CD160 CAN INHIBIT THE SECRETION OF IFN-GAMMA AND TNF-ALPHA THROUGH HDAC11 RECRUITMENT AND BIND TO HDAC11 TO FORM A COMPLEX ON THE PROMOTERS OF IFN-GAMMA AND TNF-ALPHA. THE HDAC11, IFN-GAMMA AND TNF-ALPHA FORM A COMPLEX AND ENHANCE THE METHYLATION OF H3K9ME1, CHROMATIN CHANGES INTO THE HETEROCHROMATIN AND THE TRANSCRIPTION OF IFN-GAMMA AND TNF-ALPHA IS BLOCKED; MOREOVER, THE HDAC11/IFN-GAMMA/TNF-ALPHA COMPLEX CAN ALSO INHIBIT THE SECRETION OF IFN-GAMMA AND TNF-ALPHA IN CD160(-) CD8(+) T CELLS AND SUPPRESSES THE FUNCTION OF CD8(+) T CELLS. FURTHERMORE, SMALL INTERFERING RNA TARGETING LNCRNA-CD160 CAN BLOCK HBV INFECTION PROGRESSION. LNCRNA-CD160 ACTS AS AN IMMUNE SUPPRESSIVE FACTOR AND IS EXPRESSED AT A HIGH LEVEL IN PERIPHERAL BLOOD CD8(+) T CELLS OF HBV INFECTED PATIENTS. FURTHERMORE, HIGH EXPRESSION LEVELS OF LNCRNA-CD160 CAN CONTRIBUTE TO THE INHIBITION OF IFN-GAMMA AND TNF-ALPHA SECRETION IN CD8(+) T CELLS AND DECREASE THE IMMUNE RESPONSE OF CD8(+) T CELLS. THEREFORE, LNCRNA-CD160 MAY BECOME A NEW TARGET FOR IMMUNOTHERAPY OF CHRONIC HBV INFECTION IN THE FUTURE AND MAY PROVIDE A NEW THERAPEUTIC STRATEGY FOR THE TREATMENT OF HBV INFECTION. 2020 10 819 33 CHARACTERIZATION OF A KDM5 SMALL MOLECULE INHIBITOR WITH ANTIVIRAL ACTIVITY AGAINST HEPATITIS B VIRUS. CHRONIC HEPATITIS B (CHB) IS A GLOBAL HEALTH CARE CHALLENGE AND A MAJOR CAUSE OF LIVER DISEASE. TO FIND NEW THERAPEUTIC AVENUES WITH A POTENTIAL TO FUNCTIONALLY CURE CHRONIC HEPATITIS B VIRUS (HBV) INFECTION, WE PERFORMED A FOCUSED SCREEN OF EPIGENETIC MODIFIERS TO IDENTIFY POTENTIAL INHIBITORS OF REPLICATION OR GENE EXPRESSION. FROM THIS WORK WE IDENTIFIED ISONICOTINIC ACID INHIBITORS OF THE HISTONE LYSINE DEMETHYLASE 5 (KDM5) WITH POTENT ANTI-HBV ACTIVITY. TO ENHANCE THE CELLULAR PERMEABILITY AND LIVER ACCUMULATION OF THE MOST POTENT KDM5 INHIBITOR IDENTIFIED (GS-080) AN ESTER PRODRUG WAS DEVELOPED (GS-5801) THAT RESULTED IN IMPROVED BIOAVAILABILITY AND LIVER EXPOSURE AS WELL AS AN INCREASED H3K4ME3:H3 RATIO ON CHROMATIN. GS-5801 TREATMENT OF HBV-INFECTED PRIMARY HUMAN HEPATOCYTES REDUCED THE LEVELS OF HBV RNA, DNA AND ANTIGEN. EVALUATION OF GS-5801 ANTIVIRAL ACTIVITY IN A HUMANIZED MOUSE MODEL OF HBV INFECTION, HOWEVER, DID NOT RESULT IN ANTIVIRAL EFFICACY, DESPITE ACHIEVING PHARMACODYNAMIC LEVELS OF H3K4ME3:H3 PREDICTED TO BE EFFICACIOUS FROM THE IN VITRO MODEL. HERE WE DISCUSS POTENTIAL REASONS FOR THE DISCONNECT BETWEEN IN VITRO AND IN VIVO EFFICACY, WHICH HIGHLIGHT THE TRANSLATIONAL DIFFICULTIES OF EPIGENETIC TARGETS FOR VIRAL DISEASES. 2022 11 3186 39 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 12 4056 49 MAPPING THE HETEROGENEITY OF HISTONE MODIFICATIONS ON HEPATITIS B VIRUS DNA USING LIVER NEEDLE BIOPSIES OBTAINED FROM CHRONICALLY INFECTED PATIENTS. COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) FORMS THE BASIS FOR REPLICATION AND PERSISTENCE OF HEPATITIS B VIRUS (HBV) IN THE CHRONICALLY INFECTED LIVER. WE HAVE PREVIOUSLY SHOWN THAT VIRAL TRANSCRIPTION IS SUBJECT TO REGULATION BY POSTTRANSLATIONAL MODIFICATIONS (PTMS) OF HISTONE PROTEINS BOUND TO CCCDNA THROUGH ANALYSIS OF DE NOVO HBV-INFECTED CELL LINES. WE NOW REPORT THE SUCCESSFUL ADAPTATION OF THIS CHROMATIN IMMUNOPRECIPITATION SEQUENCING (CHIPSEQ) APPROACH FOR ANALYSIS OF FINE-NEEDLE PATIENT LIVER BIOPSY SPECIMENS TO INVESTIGATE THE ROLE OF HISTONE PTMS IN CHRONICALLY HBV-INFECTED PATIENTS. USING 18 SPECIMENS FROM PATIENTS IN DIFFERENT STAGES OF CHRONIC HBV INFECTION, OUR WORK SHOWS THAT THE PROFILE OF HISTONE PTMS IN CHRONIC INFECTION IS MORE NUANCED THAN PREVIOUSLY OBSERVED IN IN VITRO MODELS OF ACUTE INFECTION. IN LINE WITH OUR PREVIOUS FINDINGS, WE FIND THAT THE MAJORITY OF HBV-DERIVED SEQUENCES ARE ASSOCIATED WITH THE ACTIVATING HISTONE PTM H3K4ME3. HOWEVER, WE SHOW A STRIKING INTERPATIENT VARIABILITY OF ITS DEPOSITION IN THIS PATIENT COHORT CORRELATED WITH VIRAL TRANSCRIPTION AND PATIENT HBV EARLY ANTIGEN (HBEAG) STATUS. UNEXPECTEDLY, WE DETECTED DEPOSITION OF THE CLASSICAL INHIBITORY HISTONE PTM H3K9ME3 ON HBV-DNA IN AROUND HALF OF THE PATIENT BIOPSY SPECIMENS, WHICH COULD NOT BE LINKED TO REDUCED LEVELS OF VIRAL TRANSCRIPTS. OUR RESULTS SHOW THAT CURRENT IN VITRO MODELS ARE UNABLE TO FULLY RECAPITULATE THE COMPLEX EPIGENETIC LANDSCAPE OF CHRONIC HBV INFECTION OBSERVED IN VIVO AND DEMONSTRATE THAT FINE-NEEDLE LIVER BIOPSY SPECIMENS CAN PROVIDE SUFFICIENT MATERIAL TO FURTHER INVESTIGATE THE INTERACTION OF VIRAL AND HOST PROTEINS ON HBV-DNA.IMPORTANCE HEPATITIS B VIRUS (HBV) IS A MAJOR GLOBAL HEALTH CONCERN, CHRONICALLY INFECTING MILLIONS OF PATIENTS AND CONTRIBUTING TO A RISING BURDEN OF LIVER DISEASE. THE VIRAL GENOME FORMS THE BASIS FOR CHRONIC INFECTION AND HAS BEEN SHOWN TO BE SUBJECT TO REGULATION BY EPIGENETIC MECHANISMS, SUCH AS POSTTRANSLATIONAL MODIFICATION OF HISTONE PROTEINS. HERE, WE CONFIRM AND EXPAND ON PREVIOUS RESULTS BY ADAPTING A HIGH-RESOLUTION TECHNIQUE FOR ANALYSIS OF HISTONE MODIFICATIONS FOR USE WITH PATIENT-DERIVED FINE-NEEDLE LIVER BIOPSY SPECIMENS. OUR WORK HIGHLIGHTS THAT THE SITUATION IN VIVO IS MORE COMPLEX THAN PREDICTED BY CURRENT IN VITRO MODELS, FOR EXAMPLE, BY SUGGESTING A NOVEL, NONCANONICAL ROLE OF THE HISTONE MODIFICATION H3K9ME3 IN THE HBV LIFE CYCLE. IMPORTANTLY, ENABLING THE USE OF FINE-NEEDLE LIVER BIOPSY SPECIMENS FOR SUCH HIGH-RESOLUTION ANALYSES MAY FACILITATE FURTHER RESEARCH INTO THE EPIGENETIC REGULATION OF THE HBV GENOME. 2019 13 2395 36 EPIGENETIC REPROGRAMMING IN MIST1(-/-) MICE PREDICTS THE MOLECULAR RESPONSE TO CERULEIN-INDUCED PANCREATITIS. GENE EXPRESSION IS AFFECTED BY MODIFICATIONS TO HISTONE CORE PROTEINS WITHIN CHROMATIN. CHANGES IN THESE MODIFICATIONS, OR EPIGENETIC REPROGRAMMING, CAN DICTATE CELL FATE AND PROMOTE SUSCEPTIBILITY TO DISEASE. THE GOAL OF THIS STUDY WAS TO DETERMINE THE EXTENT OF EPIGENETIC REPROGRAMMING IN RESPONSE TO CHRONIC STRESS THAT OCCURS FOLLOWING ABLATION OF MIST1 (MIST1(-/-) ), WHICH IS REPRESSED IN PANCREATIC DISEASE. CHROMATIN IMMUNOPRECIPITATION FOR TRIMETHYLATION OF LYSINE RESIDUE 4 ON HISTONE 3 (H3K4ME3) IN PURIFIED ACINAR CELLS FROM WILD TYPE AND MIST1(-/-) MICE WAS FOLLOWED BY NEXT GENERATION SEQUENCING (CHIP-SEQ) OR CHIP-QPCR. H3K4ME3-ENRICHED GENES WERE ASSESSED FOR EXPRESSION BY QRT-PCR IN PANCREATIC TISSUE BEFORE AND AFTER INDUCTION OF CERULEIN-INDUCED PANCREATITIS. WHILE MOST OF H3K4ME3-ENRICHMENT IS RESTRICTED TO TRANSCRIPTIONAL START SITES, >25% OF ENRICHMENT SITES ARE FOUND WITHIN, DOWNSTREAM OR BETWEEN ANNOTATED GENES. LESS THAN 10% OF THESE SITES WERE ALTERED IN MIST1(-/-) ACINI, WITH MOST CHANGES IN H3K4ME3 ENRICHMENT NOT REFLECTING ALTERED GENE EXPRESSION. INGENUITY PATHWAY ANALYSIS OF GENES DIFFERENTIALLY-ENRICHED FOR H3K4ME3 REVEALED AN ASSOCIATION WITH PANCREATITIS AND PANCREATIC DUCTAL ADENOCARCINOMA IN MIST1(-/-) TISSUE. MOST OF THESE GENES WERE NOT DIFFERENTIALLY EXPRESSED BUT SEVERAL WERE READILY INDUCED BY ACUTE EXPERIMENTAL PANCREATITIS, WITH SIGNIFICANTLY INCREASED EXPRESSION IN MIST1(-/-) TISSUE RELATIVE TO WILD TYPE MICE. WE SUGGEST THAT THE CHRONIC CELL STRESS OBSERVED IN THE ABSENCE OF MIST1 RESULTS IN EPIGENETIC REPROGRAMMING OF GENES INVOLVED IN PROMOTING PANCREATITIS TO A POISED STATE, THEREBY INCREASING THE SENSITIVITY TO EVENTS THAT PROMOTE DISEASE. 2014 14 5955 36 TELBIVUDINE TREATMENT CORRECTS HBV-INDUCED EPIGENETIC ALTERATIONS IN LIVER CELLS OF PATIENTS WITH CHRONIC HEPATITIS B. HEPATITIS B VIRUS (HBV) ALTERS THE EXPRESSION OF HOST CELLULAR GENES TO SUPPORT ITS REPLICATION AND SURVIVAL AND TO PROMOTE THE LIVER CELL INJURY. HOWEVER, THE UNDERLYING MECHANISM REMAINED INCOMPLETELY UNDERSTOOD. IN THIS STUDY, WE INVESTIGATED HBV-INDUCED EPIGENETIC CHANGES IN HEPG2 CELLS BY PROFILING THE LANDSCAPES OF THE ACTIVE HISTONE MODIFICATION MARK H3K4ME3 AND REPRESSIVE MARK H3K27ME3 USING CHROMATIN IMMUNOPRECIPITATION-SEQUENCING. HBV CAUSED THE ALTERED HISTONE MODIFICATIONS AT THOUSANDS OF GENOMIC LOCI, WHICH ARE CRITICALLY INVOLVED IN HBV ENTRY, INFLAMMATION, FIBROSIS AND CARCINOGENESIS OF HOST CELLS. INTERESTINGLY, TREATMENT OF THE HBV-TRANSFORMED HEPG2 CELLS WITH THE ANTI-HBV DRUG TELBIVUDINE SUBSTANTIALLY RESTORED THE H3K4ME3 LEVEL TO THAT OF UNTRANSFORMED HEPG2 CELLS. MORE IMPORTANTLY, OUR ANALYSIS OF LIVER SAMPLES FROM CONTROL AND CHRONIC HEPATITIS B PATIENTS REVEALED THAT TREATMENT OF THE PATIENTS WITH TELBIVUDINE NOT ONLY CORRECTED THE TARGET GENE EXPRESSION BUT ALSO THE EPIGENETIC MODIFICATION OF CRITICAL GENES. IN ADDITION, THE EXPRESSION OF THE HISTONE METHYLTRANSFERASES SMYD3 AND EZH2 THAT REGULATE HISTONE H3-SPECIFIC METHYLATION SHOWED NO DIFFERENCE IN HEPG2 CELL WITH OR WITHOUT HBV EXISTENCE. THUS, OUR DATA SUGGEST THAT ABNORMAL HISTONE MODIFICATIONS MIGHT CRITICALLY INVOLVED IN HBV-MEDIATED LIVER PATHOGENESIS AND TELBIVUDINE THERAPY MIGHT BENEFIT PATIENTS WITH HBV-RELATED CHRONIC INFECTION, LIVER CIRRHOSIS AND EVEN HEPATIC CARCINOMA. SUMMARY: TELBIVUDINE SUBSTANTIALLY RESTORES IN VITRO AND IN VIVO HBV-CAUSED ABNORMAL EXPRESSIONS AND HISTONE H3K4ME3 AND H3K27ME3 MODIFICATIONS AT THOUSANDS OF GENOMIC LOCI THAT ARE INVOLVED IN THE PATHOGENESIS OF LIVER CELLS, REVEALING A NOVEL MECHANISM FOR HBV-MEDIATED LIVER DAMAGE. 2014 15 5226 46 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 5844 38 STUDY OF PROMOTER HYPOMETHYLATION PROFILES OF RAS ONCOGENES IN HEPATOCELLULAR CARCINOMA DERIVED FROM HEPATITIS C VIRUS GENOTYPE 3A IN PAKISTANI POPULATION. EPIGENETIC MODIFICATIONS SUCH AS DNA METHYLATION CONTRIBUTE TO PROGRESSION OF HEPATITIS C VIRUS (HCV) INFECTION TO LIFE-THREATENING HEPATOCELLULAR CARCINOMA (HCC) BY PROMOTING THE SILENCING OF TUMOR SUPPRESSOR GENES THROUGH DNA HYPERMETHYLATION AND BY CAUSING GENOMIC INSTABILITY THROUGH GLOBAL HYPOMETHYLATION. HOWEVER FEW STUDIES HAVE ADDRESSED THE PROMOTER REGION HYPOMETHYLATION STATUS OF THE ONCOGENES INVOLVED IN HCV DERIVED HCC. IN THIS STUDY, WE ANALYZED THE PROMOTER REGION METHYLATION PATTERN OF RAS ONCOGENES (HRAS, KRAS, AND NRAS) USING METHYLATION-SPECIFIC PCR FOR 50 CHRONIC HCV PATIENTS INFECTED WITH GENOTYPE 3A (27 HCC PATIENTS AND 23 CONTROL NON-HCC PATIENTS). METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION ANALYSIS REVEALED THAT THE NRAS ONCOGENE PROMOTER (P = .0025) WAS SIGNIFICANTLY HYPOMETHYLATED IN HCC PATIENTS COMPARED TO THE NON-HCC PATIENTS SUGGESTING ITS CONTRIBUTION TO THE PROGRESSION OF HCV TOWARDS HCC. TO IDENTIFY THE AGENT FOR ALTERATION IN THE RAS ONCOGENE EXPRESSION, 7 HCV GENES WERE EXPRESSED IN THE HUH-7 CELL LINE FOLLOWED BY MEASUREMENT OF THE NRAS EXPRESSION LEVEL IN HUH-7 BY A QUANTITATIVE REAL-TIME POLYMERASE CHAIN REACTION. AN INCREASE IN THE MESSENGER RNA LEVEL OF THE NRAS GENE WAS DETECTED WHEN HUH-7 WERE TRANSFECTED WITH CORE, NS5A, AND NS2 GENES. OUR FINDINGS SUGGEST THE INVOLVEMENT OF NRAS ONCOGENE IN THE PATHOGENESIS OF HCV3A DERIVED HCC IN PAKISTANI POPULATION AND ALSO IDENTIFIES THE HCV GENES RESPONSIBLE FOR ITS ENHANCED EXPRESSION. OUR STUDY RAISES THE HYPOTHESIS THAT A SINGLE HCV GENE MAY INCREASE THE CHANCES OF MALIGNANCY. THEREFORE, OUR STUDY MAY HAVE IDENTIFIED A USEFUL EPIGENETIC BIOMARKER OF HCC PROGRESSION IN HCV PATIENTS AND MAY HELP TO DEVELOP NOVEL DIAGNOSTIC TOOLS. 2018 17 1615 28 DNA METHYLTRANSFERASE 3B PLAYS A PROTECTIVE ROLE AGAINST HEPATOCARCINOGENESIS CAUSED BY CHRONIC INFLAMMATION VIA MAINTAINING MITOCHONDRIAL HOMEOSTASIS. MOST HEPATOCELLULAR CARCINOMAS (HCCS) DEVELOP ON THE BASIS OF CHRONIC HEPATITIS, BUT THE MECHANISM OF EPIGENETIC REGULATION IN INFLAMMATORY HEPATOCARCINOGENESIS HAS YET TO BE ELUCIDATED. AMONG DE NOVO DNA METHYLTRANSFERASES (DNMTS), DNMT3B HAS LATELY BEEN REPORTED TO ACT SPECIFICALLY ON ACTIVELY TRANSCRIBED GENES, SUGGESTING THE POSSIBILITY THAT IT PLAYS A ROLE IN THE PATHOGENESIS OF CANCER. WE CONFIRMED THAT DNMT3B ISOFORMS LACKING ITS CATALYTIC DOMAIN WERE HIGHLY EXPRESSED IN HCCS COMPARED WITH NON-TUMOROUS LIVER TISSUE. TO ELUCIDATE THE ROLE OF DNMT3B IN HEPATOCARCINOGENESIS, WE GENERATED A GENETICALLY ENGINEERED MOUSE MODEL WITH HEPATOCYTE-SPECIFIC DNMT3B DELETION. THE LIVER OF THE DNMT3B-DEFICIENT MICE EXHIBITED AN EXACERBATION OF THIOACETAMIDE-INDUCED HEPATITIS, PROGRESSION OF LIVER FIBROSIS AND A HIGHER INCIDENCE OF HCC COMPARED WITH THE LIVER OF THE CONTROL MICE. WHOLE-GENOME BISULFITE SEQUENCING VERIFIED A LOWER CG METHYLATION LEVEL IN THE DNMT3B-DEFICIENT LIVER, DEMONSTRATING DIFFERENTIALLY METHYLATED REGIONS THROUGHOUT THE GENOME. TRANSCRIPTOME ANALYSIS REVEALED DECREASED EXPRESSION OF GENES RELATED TO OXIDATIVE PHOSPHORYLATION IN THE DNMT3B-DEFICIENT LIVER. MOREOVER, PRIMARY HEPATOCYTES ISOLATED FROM THE DNMT3B-DEFICIENT MICE SHOWED REDUCED MITOCHONDRIAL RESPIRATORY CAPACITY, LEADING TO THE ENHANCEMENT OF OXIDATIVE STRESS IN THE LIVER TISSUE. OUR FINDINGS SUGGEST THE PROTECTIVE ROLE OF DNMT3B AGAINST CHRONIC INFLAMMATION AND HCC DEVELOPMENT VIA MAINTAINING MITOCHONDRIAL HOMEOSTASIS. 2020 18 155 33 ABERRANT METHYLATION OF POLO-LIKE KINASE CPG ISLANDS IN PLK4 HETEROZYGOUS MICE. BACKGROUND: HEPATOCELLULAR CARCINOMA (HCC), ONE OF THE MOST COMMON CANCERS WORLD-WIDE OCCURS TWICE AS OFTEN IN MEN COMPARED TO WOMEN. PREDISPOSING CONDITIONS SUCH AS ALCOHOLISM, CHRONIC VIRAL HEPATITIS, AFLATOXIN B1 INGESTION, AND CIRRHOSIS ALL CONTRIBUTE TO THE DEVELOPMENT OF HCC. METHODS: WE USED A COMBINATION OF METHYLATION SPECIFIC PCR AND BISULFITE SEQUENCING, QREAL-TIME PCR (QPCR), AND WESTERN BLOT ANALYSIS TO EXAMINE EPIGENETIC CHANGES FOR THE POLO-LIKE KINASES (PLKS) DURING THE DEVELOPMENT OF HEPATOCELLULAR CARCINOMA (HCC) IN PLK4 HETEROZYGOUS MICE AND MURINE EMBRYONIC FIBROBLASTS (MEFS). RESULTS: HERE WE REPORT THAT THE PROMOTER METHYLATION OF PLK4 CPG ISLANDS INCREASES WITH AGE, WAS MORE PREVALENT IN MALES AND THAT PLK4 EPIGENETIC MODIFICATION AND SUBSEQUENT DOWNREGULATION OF EXPRESSION WAS ASSOCIATED WITH THE DEVELOPMENT OF HCC IN PLK4 MUTANT MICE. INTERESTINGLY, THE OPPOSITE OCCURS WITH ANOTHER PLK FAMILY MEMBER, PLK1 WHICH WAS TYPICALLY HYPERMETHYLATED IN NORMAL LIVER TISSUE BUT BECAME HYPOMETHYLATED AND UPREGULATED IN LIVER TUMOURS. FURTHERMORE, UPON ALCOHOL EXPOSURE MURINE EMBRYONIC FIBROBLASTS EXHIBITED INCREASED PLK4 HYPERMETHYLATION AND DOWNREGULATION ALONG WITH INCREASED CENTROSOME NUMBERS AND MULTINUCLEATION. CONCLUSIONS: THESE RESULTS SUGGEST THAT ABERRANT PLK METHYLATION IS CORRELATED WITH THE DEVELOPMENT OF HCC IN MICE. 2011 19 1144 40 CONCOMITANT HETEROCHROMATINISATION AND DOWN-REGULATION OF GENE EXPRESSION UNVEILS EPIGENETIC SILENCING OF RELB IN AN AGGRESSIVE SUBSET OF CHRONIC LYMPHOCYTIC LEUKEMIA IN MALES. BACKGROUND: THE SENSITIVITY OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) CELLS TO CURRENT TREATMENTS, BOTH IN VITRO AND IN VIVO, RELIES ON THEIR ABILITY TO ACTIVATE APOPTOTIC DEATH. CLL CELLS RESISTANT TO DNA DAMAGE-INDUCED APOPTOSIS DISPLAY DEREGULATION OF A SPECIFIC SET OF GENES. METHODS: MICROARRAY HYBRIDIZATION (HUMAN GENECHIP, AFFYMETRIX), IMMUNOFLUORESCENT IN SITU LABELING COUPLED WITH VIDEO-MICROSCOPY RECORDING/ANALYSES, CHROMATIN-IMMUNOPRECIPITATION (CHIP), POLYMERASE CHAIN REACTIONS (PCR), REAL-TIME QUANTITATIVE PCR (RT-QPCR) AND BISULFITE GENOME SEQUENCING WERE THE MAIN METHODS APPLIED. STATISTICAL ANALYSES WERE PERFORMED BY APPLYING GCRMA AND SAM ANALYSIS (MICROARRAY DATA) AND STUDENT'S T-TEST OR MANN & WHITNEY'S U-TEST. RESULTS: HEREIN WE SHOW THAT, REMARKABLY, IN A RESISTANT MALE CLL CELLS THE VAST MAJORITY OF GENES WERE DOWN-REGULATED COMPARED WITH SENSITIVE CELLS, WHEREAS THIS WAS NOT THE CASE IN CELLS DERIVED FROM FEMALES. THIS GENE DOWN-REGULATION WAS FOUND TO BE ASSOCIATED WITH AN OVERALL GAIN OF HETEROCHROMATIN AS EVIDENCED BY IMMUNOFLUORESCENT LABELING OF HETEROCHROMATIN PROTEIN 1ALPHA (HP-1), TRIMETHYLATED HISTONE 3 LYSINE 9 (3METH3K9), AND 5-METHYLCYTIDINE (5METC). NOTABLY, 17 GENES WERE FOUND TO BE COMMONLY DEREGULATED IN RESISTANT MALE AND FEMALE CELL SAMPLES. AMONG THESE, RELB WAS IDENTIFIED AS A DISCRIMINATORY CANDIDATE GENE REPRESSED IN THE MALE AND UPREGULATED IN THE FEMALE RESISTANT CELLS. CONCLUSION: THE MOLECULAR DEFECTS IN THE SILENCING OF RELB INVOLVE AN INCREASE IN H3K9- BUT NOT CPG-ISLAND METHYLATION IN THE PROMOTER REGIONS. INCREASE IN ACETYL-H3 IN RESISTANT FEMALE BUT NOT MALE CLL SAMPLES AS WELL AS A DECREASE OF TOTAL CELLULAR LEVEL OF RELB AFTER AN INHIBITION OF HISTONE DEACETYLASE (HDAC) BY TRICHOSTATIN A (TSA), FURTHER EMPHASIZE THE ROLE OF EPIGENETIC MODIFICATIONS WHICH COULD DISCRIMINATE TWO CLL SUBSETS. TOGETHER, THESE RESULTS HIGHLIGHTED THE EPIGENETIC RELB SILENCING AS A NEW MARKER OF THE PROGRESSIVE DISEASE IN MALES. 2010 20 412 39 ANALYSIS OF LONG NON-CODING RNA (LNCRNA) EXPRESSION IN HEPATITIS B PATIENTS. LONG NON-CODING RNAS (LNCRNAS) HAVE BEEN IMPLICATED IN NUMEROUS BIOLOGICAL PROCESSES, INCLUDING EPIGENETIC REGULATION, CELL-CYCLE CONTROL, AND TRANSCRIPTIONAL/TRANSLATIONAL REGULATION OF GENE EXPRESSION. DIFFERENTIAL EXPRESSION OF LNCRNAS AND DISRUPTION OF THE REGULATORY PROCESSES ARE RECOGNIZED AS CRITICAL STEPS IN CANCER DEVELOPMENT. THE ROLE OF LNCRNAS IN HEPATITIS B VIRUS (HBV) INFECTION IS NOT WELL UNDERSTOOD. HERE WE ANALYZED THE EXPRESSION OF 135 LNCRNAS IN PLASMA SAMPLES OF 82 HBV PATIENTS (CLASSIFIED AS CHRONIC PATIENTS, INACTIVE CARRIERS, OR RESOLVED PATIENTS) AT DIAGNOSIS AND AT 12 MONTHS OF TREATMENT IN RELATION TO CONTROL GROUP (81 HEALTHY VOLUNTEERS). WE ALSO INVESTIGATED THE EFFECT OF SMALL INTERFERING RNA (SIRNA)-MEDIATED SILENCING OF LINCRNA-SFMBT2 ON HBV-POSITIVE HUMAN LIVER CANCER CELL LINE. LNCRNA EXPRESSION WAS ANALYZED BY QUANTITATIVE REVERSE TRANSCRIPTION-POLYMERASE CHAIN REACTION (QRT-PCR). CHEMICALLY SYNTHESIZED SIRNAS WERE TRANSFECTED INTO THE CELL LINES USING LIPOFECTAMINE 2000 REAGENT (THERMO FISHER SCIENTIFIC). HBV DNA AND HBSAG AND HBEAG WERE DETECTED IN TRANSFECTED CULTURES BY REAL-TIME PCR AND ELISA, RESPECTIVELY, USING COMMERCIAL KITS. WE OBSERVED CHANGES IN LNCRNA EXPRESSION IN ALL THREE HBV GROUPS, COMPARED TO CONTROL GROUP. MOST NOTABLY, THE EXPRESSION OF ANTI-NOS2A, LINCRNA-SFMBT2, AND ZFHX2AS WAS SIGNIFICANTLY INCREASED AND EXPRESSION OF Y5 LNCRNA WAS DECREASED IN CHRONIC HBV PATIENTS. A DECREASED Y5 EXPRESSION AND INCREASED LINCRNA-SFMBT2 EXPRESSION WERE OBSERVED IN INACTIVE HBSAG CARRIERS. THE EXPRESSION OF HOTTIP, MEG9, AND PCAT-32 WAS INCREASED IN RESOLVED HBV PATIENTS, AND NO SIGNIFICANT CHANGE IN THE EXPRESSION OF Y5 WAS OBSERVED, COMPARED TO CONTROL GROUP. SIRNA-MEDIATED INHIBITION OF LINCRNA-SFMBT2 DECREASED THE LEVEL OF HBV DNA IN HUMAN LIVER CANCER CELLS. FURTHER RESEARCH IS NEEDED TO CONFIRM THE PROGNOSTIC AS WELL AS THERAPEUTIC ROLE OF THESE LNCRNAS IN HBV PATIENTS. 2018