1 6176 100 THE HISTONE H3 LYSINE-27 DEMETHYLASE JMJD3 LINKS INFLAMMATION TO INHIBITION OF POLYCOMB-MEDIATED GENE SILENCING. EPIGENETIC CHROMATIN MARKS RESTRICT THE ABILITY OF DIFFERENTIATED CELLS TO CHANGE GENE EXPRESSION PROGRAMS IN RESPONSE TO ENVIRONMENTAL CUES AND TO TRANSDIFFERENTIATE. POLYCOMB GROUP (PCG) PROTEINS MEDIATE GENE SILENCING AND REPRESS TRANSDIFFERENTIATION IN A MANNER DEPENDENT ON HISTONE H3 LYSINE 27 TRIMETHYLATION (H3K27ME3). HOWEVER, MACROPHAGES MIGRATED INTO INFLAMED TISSUES CAN TRANSDIFFERENTIATE, BUT IT IS UNKNOWN WHETHER INFLAMMATION ALTERS PCG-DEPENDENT SILENCING. HERE WE SHOW THAT THE JMJC-DOMAIN PROTEIN JMJD3 IS A H3K27ME DEMETHYLASE EXPRESSED IN MACROPHAGES IN RESPONSE TO BACTERIAL PRODUCTS AND INFLAMMATORY CYTOKINES. JMJD3 BINDS PCG TARGET GENES AND REGULATES THEIR H3K27ME3 LEVELS AND TRANSCRIPTIONAL ACTIVITY. THE DISCOVERY OF AN INDUCIBLE ENZYME THAT ERASES A HISTONE MARK CONTROLLING DIFFERENTIATION AND CELL IDENTITY PROVIDES A LINK BETWEEN INFLAMMATION AND REPROGRAMMING OF THE EPIGENOME, WHICH COULD BE THE BASIS FOR MACROPHAGE PLASTICITY AND MIGHT EXPLAIN THE DIFFERENTIATION ABNORMALITIES IN CHRONIC INFLAMMATION. 2007 2 35 34 A CHROMATIN ACTIVITY-BASED CHEMOPROTEOMIC APPROACH REVEALS A TRANSCRIPTIONAL REPRESSOME FOR GENE-SPECIFIC SILENCING. IMMUNE CELLS DEVELOP ENDOTOXIN TOLERANCE (ET) AFTER PROLONGED STIMULATION. ET INCREASES THE LEVEL OF A REPRESSION MARK H3K9ME2 IN THE TRANSCRIPTIONALLY SILENT CHROMATIN SPECIFICALLY ASSOCIATED WITH PRO-INFLAMMATORY GENES. HOWEVER, IT IS NOT CLEAR WHAT PROTEINS ARE FUNCTIONALLY INVOLVED IN THIS PROCESS. HERE WE SHOW THAT A NOVEL CHROMATIN ACTIVITY-BASED CHEMOPROTEOMIC (CHAC) APPROACH CAN DISSECT THE FUNCTIONAL CHROMATIN PROTEIN COMPLEXES THAT REGULATE ET-ASSOCIATED INFLAMMATION. USING UNC0638 THAT BINDS THE ENZYMATICALLY ACTIVE H3K9-SPECIFIC METHYLTRANSFERASE G9A/GLP, CHAC REVEALS THAT G9A IS CONSTITUTIVELY ACTIVE AT A G9A-DEPENDENT MEGA-DALTON REPRESSOME IN PRIMARY ENDOTOXIN-TOLERANT MACROPHAGES. G9A/GLP BROADLY IMPACTS THE ET-SPECIFIC REPROGRAMMING OF THE HISTONE CODE LANDSCAPE, CHROMATIN REMODELLING AND THE ACTIVITIES OF SELECT TRANSCRIPTION FACTORS. WE DISCOVER THAT THE G9A-DEPENDENT EPIGENETIC ENVIRONMENT PROMOTES THE TRANSCRIPTIONAL REPRESSION ACTIVITY OF C-MYC FOR GENE-SPECIFIC CO-REGULATION OF CHRONIC INFLAMMATION. CHAC MAY ALSO BE APPLICABLE TO DISSECT OTHER FUNCTIONAL PROTEIN COMPLEXES IN THE CONTEXT OF PHENOTYPIC CHROMATIN ARCHITECTURES. 2014 3 4443 27 MOLECULAR INSIGHTS INTO SPINDLIN1-HBX INTERPLAY AND ITS IMPACT ON HBV TRANSCRIPTION FROM CCCDNA MINICHROMOSOME. MOLECULAR INTERPLAY BETWEEN HOST EPIGENETIC FACTORS AND VIRAL PROTEINS CONSTITUTES AN INTRIGUING MECHANISM FOR SUSTAINING HEPATITIS B VIRUS (HBV) LIFE CYCLE AND ITS CHRONIC INFECTION. HBV ENCODES A REGULATORY PROTEIN, HBX, WHICH ACTIVATES TRANSCRIPTION AND REPLICATION OF HBV GENOME ORGANIZED AS COVALENTLY CLOSED CIRCULAR (CCC) DNA MINICHROMOSOME. HERE WE ILLUSTRATE HOW HBX ACCOMPLISHES ITS TASK BY HIJACKING SPINDLIN1, AN EPIGENETIC READER COMPRISING THREE CONSECUTIVE TUDOR DOMAINS. OUR BIOCHEMICAL AND STRUCTURAL STUDIES HAVE REVEALED THAT THE HIGHLY CONSERVED N-TERMINAL 2-21 SEGMENT OF HBX (HBX(2-21)) ASSOCIATES INTIMATELY WITH TUDOR 3 OF SPINDLIN1, ENHANCING HISTONE H3 "K4ME3-K9ME3" READOUT BY TUDORS 2 AND 1. FUNCTIONALLY, SPINDLIN1-HBX ENGAGEMENT PROMOTES GENE EXPRESSION FROM THE CHROMATINIZED CCCDNA, ACCOMPANIED BY AN EPIGENETIC SWITCH FROM AN H3K9ME3-ENRICHED REPRESSIVE STATE TO AN H3K4ME3-MARKED ACTIVE STATE, AS WELL AS A CONFORMATIONAL SWITCH OF HBX THAT MAY OCCUR IN COORDINATION WITH OTHER HBX-BINDING FACTORS, SUCH AS DDB1. DESPITE A PROPOSED TRANSREPRESSION ACTIVITY OF HBX(2-21), OUR STUDY REVEALS A KEY ROLE OF SPINDLIN1 IN DEREPRESSING THIS CONSERVED MOTIF, THEREBY PROMOTING HBV TRANSCRIPTION FROM ITS CHROMATINIZED GENOME. 2023 4 5228 28 PRMT7 TARGETS OF FOXM1 CONTROLS ALVEOLAR MYOFIBROBLAST PROLIFERATION AND DIFFERENTIATION DURING ALVEOLOGENESIS. ALTHOUGH ABERRANT ALVEOLAR MYOFIBROBLASTS (AMYFS) PROLIFERATION AND DIFFERENTIATION ARE OFTEN ASSOCIATED WITH ABNORMAL LUNG DEVELOPMENT AND DISEASES, SUCH AS BRONCHOPULMONARY DYSPLASIA (BPD), CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD), AND IDIOPATHIC PULMONARY FIBROSIS (IPF), EPIGENETIC MECHANISMS REGULATING PROLIFERATION AND DIFFERENTIATION OF AMYFS REMAIN POORLY UNDERSTOOD. PROTEIN ARGININE METHYLTRANSFERASE 7 (PRMT7) IS THE ONLY REPORTED TYPE III ENZYME RESPONSIBLE FOR MONOMETHYLATION OF ARGININE RESIDUE ON BOTH HISTONE AND NONHISTONE SUBSTRATES. HERE WE PROVIDE EVIDENCE FOR PRMT7'S FUNCTION IN REGULATING AMYFS PROLIFERATION AND DIFFERENTIATION DURING LUNG ALVEOLOGENESIS. IN PRMT7-DEFICIENT MICE, WE FOUND REDUCED AMYFS PROLIFERATION AND DIFFERENTIATION, ABNORMAL ELASTIN DEPOSITION, AND FAILURE OF ALVEOLAR SEPTUM FORMATION. WE FURTHER SHOWN THAT ONCOGENE FORKHEAD BOX M1 (FOXM1) IS A DIRECT TARGET OF PRMT7 AND THAT PRMT7-CATALYZED MONOMETHYLATION AT HISTONE H4 ARGININE 3 (H4R3ME1) DIRECTLY ASSOCIATE WITH CHROMATIN OF FOXM1 TO ACTIVATE ITS TRANSCRIPTION, AND THEREBY REGULATE OF CELL CYCLE-RELATED GENES TO INHIBIT AMYFS PROLIFERATION AND DIFFERENTIATION. OVEREXPRESSION OF FOXM1 IN ISOLATED MYOFIBROBLASTS (MYFS) SIGNIFICANTLY RESCUED PRMT7-DEFICIENCY-INDUCED CELL PROLIFERATION AND DIFFERENTIATION DEFECTS. THUS, OUR RESULTS REVEAL A NOVEL EPIGENETIC MECHANISM THROUGH WHICH PRMT7-MEDIATED HISTONE ARGININE MONOMETHYLATION ACTIVATES FOXM1 TRANSCRIPTIONAL EXPRESSION TO REGULATE AMYFS PROLIFERATION AND DIFFERENTIATION DURING LUNG ALVEOLOGENESIS AND MAY REPRESENT A POTENTIAL TARGET FOR INTERVENTION IN PULMONARY DISEASES. 2021 5 3365 21 HISTONE METHYLATION IN PRE-CANCEROUS LIVER DISEASES AND HEPATOCELLULAR CARCINOMA: RECENT OVERVIEW. HEPATOCELLULAR CARCINOMA (HCC) IS THE PREVALENT FORM OF LIVER CANCER IN ADULTS AND THE FOURTH MOST COMMON CAUSE OF CANCER-RELATED DEATH WORLDWIDE. HCC PREDOMINANTLY ARISES IN THE CONTEXT OF CIRRHOSIS AS A RESULT OF CHRONIC LIVER DISEASE, INJURY AND INFLAMMATION. FULL-BLOWN HCC HAS POOR PROGNOSIS BECAUSE IT IS HIGHLY AGGRESSIVE AND RESISTANT TO THERAPY. CONSEQUENTLY, INTERVENTIONS THAT CAN PREVENT OR RESTRAIN HCC EMERGENCE FROM PRE-CANCEROUS DISEASED LIVER ARE A DESIRABLE STRATEGY. HISTONE METHYLATION IS A DYNAMIC, REVERSIBLE EPIGENETIC MODIFICATION INVOLVING THE ADDITION OR REMOVAL OF METHYL GROUPS FROM LYSINE, ARGININE OR GLUTAMINE RESIDUES. ABERRANT ACTIVITY OF HISTONE METHYLATION WRITERS, ERASES AND READERS HAS BEEN IMPLICATED IN SEVERAL CANCER TYPES, INCLUDING HCC. IN THIS REVIEW, WE PROVIDE AN OVERVIEW OF RESEARCH ON THE ROLE OF HISTONE METHYLATION IN PRE-CANCEROUS AND CANCEROUS HCC PUBLISHED OVER THE LAST 5 YEARS. IN PARTICULAR, WE PRESENT THE EVIDENCE LINKING ENVIRONMENTAL FACTORS SUCH AS DIET, VIRAL INFECTIONS AND CARCINOGENIC AGENTS WITH DYSREGULATION OF HISTONE METHYLATION DURING LIVER CANCER PROGRESSION WITH THE AIM TO HIGHLIGHT FUTURE THERAPEUTIC POSSIBILITIES. 2023 6 5298 27 PROTEIN ARGININE METHYLTRANSFERASE 5 SUPPRESSES THE TRANSCRIPTION OF THE RB FAMILY OF TUMOR SUPPRESSORS IN LEUKEMIA AND LYMPHOMA CELLS. THE PROPER EPIGENETIC MODIFICATION OF CHROMATIN BY PROTEIN ARGININE METHYLTRANSFERASES (PRMTS) IS CRUCIAL FOR NORMAL CELL GROWTH AND HEALTH. THE HUMAN SWI/SNF-ASSOCIATED PRMT5 IS INVOLVED IN THE TRANSCRIPTIONAL REPRESSION OF TARGET GENES BY DIRECTLY METHYLATING H3R8 AND H4R3. TO FURTHER UNDERSTAND THE IMPACT OF PRMT5-MEDIATED HISTONE METHYLATION ON CANCER, WE ANALYZED ITS EXPRESSION IN NORMAL AND TRANSFORMED HUMAN B LYMPHOCYTES. OUR FINDINGS REVEAL THAT PRMT5 PROTEIN LEVELS ARE ENHANCED IN VARIOUS HUMAN LYMPHOID CANCER CELLS, INCLUDING TRANSFORMED CHRONIC LYMPHOCYTIC LEUKEMIA (B-CLL) CELL LINES. PRMT5 OVEREXPRESSION IS CAUSED BY THE ALTERED EXPRESSION OF THE PRMT5-SPECIFIC MICRORNAS 19A, 25, 32, 92, 92B, AND 96 AND RESULTS IN THE INCREASED GLOBAL SYMMETRIC METHYLATION OF H3R8 AND H4R3. AN EVALUATION OF BOTH EPIGENETIC MARKS AT PRMT5 TARGET GENES SUCH AS RB1 (P105), RBL1 (P107), AND RBL2 (P130) SHOWED THAT PROMOTERS H3R8 AND H4R3 ARE HYPERMETHYLATED, WHICH IN TURN TRIGGERS POCKET PROTEIN TRANSCRIPTIONAL REPRESSION. FURTHERMORE, REDUCING PRMT5 EXPRESSION IN WAC3CD5 B-CLL CELLS ABOLISHES H3R8 AND H4R3 HYPERMETHYLATION, RESTORES RBL2 EXPRESSION, AND INHIBITS CANCER CELL PROLIFERATION. THESE RESULTS INDICATE THAT PRMT5 OVEREXPRESSION EPIGENETICALLY ALTERS THE TRANSCRIPTION OF KEY TUMOR SUPPRESSOR GENES AND SUGGEST A CAUSAL ROLE OF THE ELEVATED SYMMETRIC METHYLATION OF H3R8 AND H4R3 AT THE RBL2 PROMOTER IN TRANSFORMED B-LYMPHOCYTE PATHOLOGY. 2008 7 2372 27 EPIGENETIC REGULATION OF THE IL-13-INDUCED HUMAN EOTAXIN-3 GENE BY CREB-BINDING PROTEIN-MEDIATED HISTONE 3 ACETYLATION. THE ETIOLOGY OF A VARIETY OF CHRONIC INFLAMMATORY DISORDERS HAS BEEN ATTRIBUTED TO THE INTERACTION OF GENETIC AND ENVIRONMENTAL FACTORS. HEREIN, WE IDENTIFIED A LINK BETWEEN EPIGENETIC REGULATION AND IL-13-DRIVEN EOTAXIN-3 IN THE PATHOGENESIS OF CHRONIC ALLERGIC INFLAMMATION. WE FIRST DEMONSTRATED THAT THE CAMP-RESPONSIVE ELEMENT (CRE) SITE IN THE EOTAXIN-3 PROMOTER AFFECTS IL-13-INDUCED EOTAXIN-3 PROMOTER ACTIVITY. FURTHERMORE, THE CRE-BINDING PROTEIN-BINDING PROTEIN (CBP), A HISTONE ACETYLTRANSFERASE, INDUCED BASE-LINE AND IL-13-INDUCED EOTAXIN-3 PROMOTER ACTIVITY. ADDITIONALLY, IL-13 TREATMENT PROMOTED GLOBAL HISTONE 3 ACETYLATION AS WELL AS THE FORMATION OF A COMPLEX CONTAINING CBP AND STAT6 AND THE SUBSEQUENT ACETYLATION OF HISTONE 3 AT THE EOTAXIN-3 PROMOTER. CBP GENE SILENCING DECREASED IL-13-INDUCED TRANSCRIPTION OF EOTAXIN-3. CONVERSELY, INHIBITION OF HISTONE DEACETYLATION INCREASED IL-13-INDUCED EOTAXIN-3 PRODUCTION. CLINICAL STUDIES DEMONSTRATED MARKEDLY INCREASED GLOBAL ACETYLATION OF HISTONE 3 IN THE INFLAMED TISSUE OF PATIENTS WITH ALLERGIC INFLAMMATION. COLLECTIVELY, THESE RESULTS IDENTIFY AN EPIGENETIC MECHANISM INVOLVING CBP AND CHROMATIN REMODELING IN REGULATING IL-13-INDUCED CHEMOKINE TRANSCRIPTION. 2011 8 5510 27 RIBAVIRIN RESTORES IFNALPHA RESPONSIVENESS IN HCV-INFECTED LIVERS BY EPIGENETIC REMODELLING AT INTERFERON STIMULATED GENES. OBJECTIVES: CAVEATS IN THE UNDERSTANDING OF RIBAVIRIN (RBV) MECHANISMS OF ACTION HAS SOMEHOW PREVENTED THE DEVELOPMENT OF BETTER ANALOGUES ABLE TO FURTHER IMPROVE ITS THERAPEUTIC CONTRIBUTION IN INTERFERON (IFN)-BASED AND DIRECT ANTIVIRAL AGENT-BASED REGIMENS FOR CHRONIC HCV OR OTHER INDICATIONS. HERE, WE DESCRIBE A NEW MECHANISM BY WHICH RBV MODULATES IFN-STIMULATED GENES (ISGS) AND CONTRIBUTES TO RESTORE HEPATIC IMMUNE RESPONSIVENESS. DESIGN: RBV EFFECT ON ISG EXPRESSION WAS MONITORED IN VITRO AND IN VIVO, THAT IS, IN NON-TRANSFORMED HEPATOCYTES AND IN THE LIVER OF RBV MONO-TREATED PATIENTS, RESPECTIVELY. MODULATION OF HISTONE MODIFICATIONS AND RECRUITMENT OF HISTONE-MODIFYING ENZYMES AT TARGET PROMOTERS WAS ANALYSED BY CHROMATIN IMMUNOPRECIPITATION IN RBV-TREATED PRIMARY HUMAN HEPATOCYTES AND IN PATIENTS' LIVER BIOPSIES. RESULTS: RBV DECREASES THE MRNA LEVELS OF SEVERAL ABNORMALLY PREACTIVATED ISGS IN PATIENTS WITH HCV, WHO ARE NON-RESPONDERS TO IFN THERAPY. RBV INCREASES G9A HISTONE METHYLTRANSFERASE RECRUITMENT AND HISTONE-H3 LYSINE-9 DIMETHYLATION/TRIMETHYLATION AT SELECTED ISG PROMOTERS IN VITRO AND IN VIVO. G9A PHARMACOLOGICAL BLOCKADE ABOLISHES RBV-INDUCED ISG DOWNREGULATION AND SEVERELY IMPAIRS RBV ABILITY TO POTENTIATE IFN ANTIVIRAL ACTION AND INDUCTION OF ISGS FOLLOWING HCV INFECTION OF PRIMARY HUMAN HEPATOCYTES. CONCLUSIONS: RBV-INDUCED EPIGENETIC CHANGES, LEADING TO DECREASED ISG EXPRESSION, RESTORE AN IFN-RESPONSIVE HEPATIC ENVIRONMENT IN PATIENTS WITH HCV, WHICH MAY ALSO PROVE USEFUL IN IFN-FREE REGIMENS. 2016 9 2880 25 FUSOBACTERIUM NUCLEATUM INFECTION IN COLORECTAL CANCER: LINKING INFLAMMATION, DNA MISMATCH REPAIR AND GENETIC AND EPIGENETIC ALTERATIONS. IT HAS BEEN RECENTLY REPORTED THAT THE POPULATION OF FUSOBACTERIUM, PARTICULARLY FUSOBACTERIUM NUCLEATUM (FN), IS OVERREPRESENTED IN COLORECTAL CANCERS AND ADENOMAS. THE PROMOTING EFFECTS OF FN INFECTION ON ADENOMA AND/OR CARCINOMA FORMATION HAVE BEEN SHOWN IN APC(MIN/+)MICE. CHARACTERISTICS OF FN-ASSOCIATED CRC WERE IDENTIFIED THROUGH STUDIES USING HUMAN CRC COHORTS, AND INCLUDE RIGHT-SIDED COLON LOCATION, CPG ISLAND METHYLATION PHENOTYPE-HIGH (CIMP-H), HIGH LEVEL OF MICROSATELLITE INSTABILITY (MSI-H), AND POOR PATIENT PROGNOSIS. A SUBSET OF FN-ASSOCIATED CRC EXHIBITS A LOW LEVEL OF MICROSATELLITE INSTABILITY (MSI-L) AND ELEVATED MICROSATELLITE ALTERATIONS IN SELECTED TETRA-NUCLEOTIDE REPEATS (EMAST) INDUCED BY TRANSLOCATION OF MSH3 FROM THE NUCLEUS TO THE CYTOPLASM IN RESPONSE TO OXIDATIVE DNA DAMAGE OR INFLAMMATORY SIGNALS. THE ASSOCIATION BETWEEN CIMP/MSI-H AND FN-INFECTION CAN BE EXPLAINED BY THE ROLE OF THE MISMATCH REPAIR (MMR) PROTEIN COMPLEX FORMED BETWEEN MSH2 AND MSH6 (MUTSALPHA) TO REPAIR ABERRANT BASES GENERATED BY ROS TO FORM 7,8-DIHYDRO-8-OXO-GUANINE (8-OXOG). CLUSTERED 8-OXOGS FORMED AT CPG-RICH REGIONS INCLUDING PROMOTERS BY ROS IS REFRACTORY TO BASE EXCISION REPAIR (BER). UNDER THESE CONDITIONS, MUTSALPHA INITIATES REPAIR IN COOPERATION WITH DNA METHYLTRANSFERASES (DNMTS) AND THE POLYCOMB REPRESSIVE COMPLEX 4 (PRC4). DNMTS AT DAMAGED SITES METHYLATE CPG ISLANDS TO REPRESS TRANSCRIPTION OF TARGET GENES AND PROMOTE REPAIR REACTIONS. THUS, CONTINUOUS GENERATION OF ROS THROUGH CHRONIC FN INFECTION MAY INITIATE 1) CIMP-POSITIVE ADENOMA AND CARCINOMA IN AN MSH2/MSH6-DEPENDENT MANNER, AND/OR 2) MSI-L/EMAST CRC IN AN MSH3-DEPENDENT MANNER. THE POOR PROGNOSIS OF FN-ASSOCIATED CRC CAN BE EXPLAINED BY FN-INDUCED IMMUNE-EVASION AND/OR CHEMO-RESISTANCE. 2018 10 3875 25 KDM2A DEFICIENCY IN MACROPHAGES ENHANCES THERMOGENESIS TO PROTECT MICE AGAINST HFD-INDUCED OBESITY BY ENHANCING H3K36ME2 AT THE PPARG LOCUS. KDM2A CATALYZES H3K36ME2 DEMETHYLATION TO PLAY AN INTRIGUING EPIGENETIC REGULATORY ROLE IN CELL PROLIFERATION, DIFFERENTIATION, AND APOPTOSIS. HEREIN WE FOUND THAT MYELOID-SPECIFIC KNOCKOUT OF KDM2A (LYSM-CRE-KDM2A(F/F), KDM2A(-/-)) PROMOTED MACROPHAGE M2 PROGRAM BY REPROGRAMING METABOLIC HOMEOSTASIS THROUGH ENHANCING FATTY ACID UPTAKE AND LIPOLYSIS. KDM2A(-/-) INCREASED H3K36ME2 LEVELS AT THE PPARG LOCUS ALONG WITH AUGMENTED CHROMATIN ACCESSIBILITY AND STAT6 RECRUITMENT, WHICH RENDERED MACROPHAGES WITH PREFERENTIAL M2 POLARIZATION. THEREFORE, THE KDM2A(-/-) MICE WERE HIGHLY PROTECTED FROM HIGH-FAT DIET (HFD)-INDUCED OBESITY, INSULIN RESISTANCE, AND HEPATIC STEATOSIS, AND FEATURED BY THE REDUCED ACCUMULATION OF ADIPOSE TISSUE MACROPHAGES AND REPRESSED CHRONIC INFLAMMATION FOLLOWING HFD CHALLENGE. PARTICULARLY, KDM2A(-/-) MACROPHAGES PROVIDED A MICROENVIRONMENT IN FAVOR OF THERMOGENESIS. UPON HFD OR COLD CHALLENGE, THE KDM2A(-/-) MICE MANIFESTED HIGHER CAPACITY FOR INDUCING ADIPOSE BROWNING AND BEIGING TO PROMOTE ENERGY EXPENDITURE. COLLECTIVELY, OUR FINDINGS DEMONSTRATE THE IMPORTANCE OF KDM2A-MEDIATED H3K36 DEMETHYLATION IN ORCHESTRATING MACROPHAGE POLARIZATION, PROVIDING NOVEL INSIGHT THAT TARGETING KDM2A IN MACROPHAGES COULD BE A VIABLE THERAPEUTIC APPROACH AGAINST OBESITY AND INSULIN RESISTANCE. 2021 11 2155 28 EPIGENETIC MECHANISMS AND METABOLIC REPROGRAMMING IN FIBROGENESIS: DUAL TARGETING OF G9A AND DNMT1 FOR THE INHIBITION OF LIVER FIBROSIS. OBJECTIVE: HEPATIC STELLATE CELLS (HSC) TRANSDIFFERENTIATION INTO MYOFIBROBLASTS IS CENTRAL TO FIBROGENESIS. EPIGENETIC MECHANISMS, INCLUDING HISTONE AND DNA METHYLATION, PLAY A KEY ROLE IN THIS PROCESS. CONCERTED ACTION BETWEEN HISTONE AND DNA-MEHYLTRANSFERASES LIKE G9A AND DNMT1 IS A COMMON THEME IN GENE EXPRESSION REGULATION. WE AIMED TO STUDY THE EFFICACY OF CM272, A FIRST-IN-CLASS DUAL AND REVERSIBLE G9A/DNMT1 INHIBITOR, IN HALTING FIBROGENESIS. DESIGN: G9A AND DNMT1 WERE ANALYSED IN CIRRHOTIC HUMAN LIVERS, MOUSE MODELS OF LIVER FIBROSIS AND CULTURED MOUSE HSC. G9A AND DNMT1 EXPRESSION WAS KNOCKED DOWN OR INHIBITED WITH CM272 IN HUMAN HSC (HHSC), AND TRANSCRIPTOMIC RESPONSES TO TRANSFORMING GROWTH FACTOR-BETA1 (TGFBETA1) WERE EXAMINED. GLYCOLYTIC METABOLISM AND MITOCHONDRIAL FUNCTION WERE ANALYSED WITH SEAHORSE-XF TECHNOLOGY. GENE EXPRESSION REGULATION WAS ANALYSED BY CHROMATIN IMMUNOPRECIPITATION AND METHYLATION-SPECIFIC PCR. ANTIFIBROGENIC ACTIVITY AND SAFETY OF CM272 WERE STUDIED IN MOUSE CHRONIC CCL(4) ADMINISTRATION AND BILE DUCT LIGATION (BDL), AND IN HUMAN PRECISION-CUT LIVER SLICES (PCLSS) IN A NEW BIOREACTOR TECHNOLOGY. RESULTS: G9A AND DNMT1 WERE DETECTED IN STROMAL CELLS IN AREAS OF ACTIVE FIBROSIS IN HUMAN AND MOUSE LIVERS. G9A AND DNMT1 EXPRESSION WAS INDUCED DURING MOUSE HSC ACTIVATION, AND TGFBETA1 TRIGGERED THEIR CHROMATIN RECRUITMENT IN HHSC. G9A/DNMT1 KNOCKDOWN AND CM272 INHIBITED TGFBETA1 FIBROGENIC RESPONSES IN HHSC. TGFBETA1-MEDIATED PROFIBROGENIC METABOLIC REPROGRAMMING WAS ABROGATED BY CM272, WHICH RESTORED GLUCONEOGENIC GENE EXPRESSION AND MITOCHONDRIAL FUNCTION THROUGH ON-TARGET EPIGENETIC EFFECTS. CM272 INHIBITED FIBROGENESIS IN MICE AND PCLSS WITHOUT TOXICITY. CONCLUSIONS: DUAL G9A/DNMT1 INHIBITION BY COMPOUNDS LIKE CM272 MAY BE A NOVEL THERAPEUTIC STRATEGY FOR TREATING LIVER FIBROSIS. 2021 12 5601 27 RORALPHA IS CRUCIAL FOR ATTENUATED INFLAMMATORY RESPONSE TO MAINTAIN INTESTINAL HOMEOSTASIS. RETINOIC ACID-RELATED ORPHAN RECEPTOR ALPHA (RORALPHA) FUNCTIONS AS A TRANSCRIPTION FACTOR FOR VARIOUS BIOLOGICAL PROCESSES, INCLUDING CIRCADIAN RHYTHM, CANCER, AND METABOLISM. HERE, WE GENERATE INTESTINAL EPITHELIAL CELL (IEC)-SPECIFIC RORALPHA-DEFICIENT (RORALPHA(DELTAIEC)) MICE AND FIND THAT RORALPHA IS CRUCIAL FOR MAINTAINING INTESTINAL HOMEOSTASIS BY ATTENUATING NUCLEAR FACTOR KAPPAB (NF-KAPPAB) TRANSCRIPTIONAL ACTIVITY. RORALPHA(DELTAIEC) MICE EXHIBIT EXCESSIVE INTESTINAL INFLAMMATION AND HIGHLY ACTIVATED INFLAMMATORY RESPONSES IN THE DEXTRAN SULFATE SODIUM (DSS) MOUSE COLITIS MODEL. TRANSCRIPTOME ANALYSIS REVEALS THAT DELETION OF RORALPHA LEADS TO UP-REGULATION OF NF-KAPPAB TARGET GENES IN IECS. CHROMATIN IMMUNOPRECIPITATION ANALYSIS REVEALS CORECRUITMENT OF RORALPHA AND HISTONE DEACETYLASE 3 (HDAC3) ON NF-KAPPAB TARGET PROMOTERS AND SUBSEQUENT DISMISSAL OF CREB BINDING PROTEIN (CBP) AND BROMODOMAIN-CONTAINING PROTEIN 4 (BRD4) FOR TRANSCRIPTIONAL REPRESSION. TOGETHER, WE DEMONSTRATE THAT RORALPHA/HDAC3-MEDIATED ATTENUATION OF NF-KAPPAB SIGNALING CONTROLS THE BALANCE OF INFLAMMATORY RESPONSES, AND THERAPEUTIC STRATEGIES TARGETING THIS EPIGENETIC REGULATION COULD BE BENEFICIAL TO THE TREATMENT OF CHRONIC INFLAMMATORY DISEASES, INCLUDING INFLAMMATORY BOWEL DISEASE (IBD). 2019 13 1668 28 DOWNREGULATION OF SOCS1 INCREASES INTERFERON-INDUCED ISGYLATION DURING DIFFERENTIATION OF INDUCED-PLURIPOTENT STEM CELLS TO HEPATOCYTES. BACKGROUND & AIMS: INCREASED EXPRESSION OF IFN-STIMULATED GENE 15 (ISG15) AND SUBSEQUENTLY INCREASED ISGYLATION ARE KEY FACTORS IN THE HOST RESPONSE TO VIRAL INFECTION. IN THIS STUDY, WE SOUGHT TO CHARACTERIZE THE EXPRESSION OF ISG15, ISGYLATION, AND ASSOCIATED ENZYMES AT EACH STAGE OF DIFFERENTIATION FROM INDUCED PLURIPOTENT STEM CELLS (IPSCS) TO HEPATOCYTES. METHODS: TO STUDY THE REGULATION OF ISGYLATION, WE UTILIZED PATIENT SAMPLES AND IN VITRO CELL CULTURE MODELS INCLUDING IPSCS, HEPATOCYTES-LIKE CELLS, IMMORTALIZED CELL LINES, AND PRIMARY HUMAN HEPATOCYTES. PROTEIN/MRNA EXPRESSION WERE MEASURED FOLLOWING TREATMENT WITH POLY(I:C), IFNALPHA AND HCV INFECTION. RESULTS: WHEN COMPARED TO HLCS, WE OBSERVED SEVERAL NOVEL ASPECTS OF THE ISGYLATION PATHWAY IN IPSCS. THESE INCLUDE A LOWER BASELINE EXPRESSION OF THE ISGYLATION-ACTIVATING ENZYME, UBE1L, A LACK OF IFN-INDUCED EXPRESSION OF THE ISGYLATION-CONJUGATION ENZYME UBE2L6, AN ATTENUATED ACTIVATION OF THE TRANSCRIPTION FACTOR STAT1 AND CONSTITUTIVE EXPRESSION OF SOCS1. ISGYLATION WAS OBSERVED IN IPSCS FOLLOWING DOWNREGULATION OF SOCS1, WHICH FACILITATED STAT1 ACTIVATION AND SUBSEQUENTLY INCREASED EXPRESSION OF UBE2L6. INTRIGUINGLY, HCV PERMISSIVE TRANSFORMED HEPATOMA CELL LINES DEMONSTRATED HIGHER INTRINSIC EXPRESSION OF SOCS1 AND WEAKER ISGYLATION FOLLOWING IFN TREATMENT. SOCS1 DOWNREGULATION IN HCV-INFECTED HUH 7.5.1 CELLS LED TO INCREASED ISGYLATION. CONCLUSIONS: HEREIN, WE SHOW THAT HIGH BASAL LEVELS OF SOCS1 INHIBIT STAT1 ACTIVATION AND SUBSEQUENTLY IFN-INDUCED UBE2L6 AND ISGYLATION IN IPSCS. FURTHERMORE, AS IPSCS DIFFERENTIATE INTO HEPATOCYTES, EPIGENETIC MECHANISMS REGULATE ISGYLATION BY MODIFYING UBE1L AND SOCS1 EXPRESSION LEVELS. OVERALL, THIS STUDY DEMONSTRATES THAT THE DEVELOPMENT OF CELL-INTRINSIC INNATE IMMUNITY DURING THE DIFFERENTIATION OF IPSCS TO HEPATOCYTES PROVIDES INSIGHT INTO CELL TYPE-SPECIFIC REGULATION OF HOST DEFENSE RESPONSES AND RELATED ONCOGENIC PROCESSES. IMPACT AND IMPLICATIONS: TO ELUCIDATE THE MECHANISM UNDERLYING REGULATION OF ISGYLATION, A KEY PROCESS IN THE INNATE IMMUNE RESPONSE, WE STUDIED CHANGES IN ISGYLATION-ASSOCIATED GENES AT THE DIFFERENT STAGES OF DIFFERENTIATION FROM IPSCS TO HEPATOCYTES. WE FOUND THAT HIGH BASAL LEVELS OF SOCS1 INHIBIT STAT1 ACTIVATION AND SUBSEQUENTLY IFN-INDUCED UBE2L6 AND ISGYLATION IN IPSCS. IMPORTANTLY, EPIGENETIC REGULATION OF SOCS1 AND SUBSEQUENTLY ISGYLATION MAY BE IMPORTANT FACTORS IN THE DEVELOPMENT OF CELL TYPE-SPECIFIC HOST DEFENSE RESPONSES IN HEPATOCYTES THAT SHOULD BE CONSIDERED WHEN STUDYING CHRONIC INFECTIONS AND ONCOGENIC PROCESSES IN THE LIVER. 2022 14 1171 24 CONTRIBUTION OF MATURE HEPATOCYTES TO BILIARY REGENERATION IN RATS WITH ACUTE AND CHRONIC BILIARY INJURY. WHETHER HEPATOCYTES CAN CONVERT INTO BILIARY EPITHELIAL CELLS (BECS) DURING BILIARY INJURY IS MUCH DEBATED. TO TEST THIS CONCEPT, WE TRACED THE FATE OF GENETICALLY LABELED [DIPEPTIDYL PEPTIDASE IV (DPPIV)-POSITIVE] HEPATOCYTES IN HEPATOCYTE TRANSPLANTATION MODEL FOLLOWING ACUTE HEPATO-BILIARY INJURY INDUCED BY 4,4'-METHYLENE-DIANILINE (DAPM) AND D-GALACTOSAMINE (DAPM+D-GAL) AND IN DPPIV-CHIMERIC LIVER MODEL SUBJECTED TO ACUTE (DAPM+D-GAL) OR CHRONIC BILIARY INJURY CAUSED BY DAPM AND BILE DUCT LIGATION (DAPM+BDL). IN BOTH MODELS BEFORE BILIARY INJURY, BECS ARE UNIFORMLY DPPIV-DEFICIENT AND PROLIFERATION OF DPPIV-DEFICIENT HEPATOCYTES IS RESTRICTED BY RETRORSINE. WE FOUND THAT MATURE HEPATOCYTES UNDERWENT A STEPWISE CONVERSION INTO BECS AFTER BILIARY INJURY. IN THE HEPATOCYTE TRANSPLANTATION MODEL, DPPIV-POSITIVE HEPATOCYTES ENTRAPPED PERIPORTALLY PROLIFERATED, AND FORMED TWO-LAYERED PLATES ALONG PORTAL VEINS. WITHIN THE TWO-LAYERED PLATES, THE HEPATOCYTES GRADUALLY LOST THEIR HEPATOCYTIC IDENTITY, PROCEEDED THROUGH AN INTERMEDIATE STATE, ACQUIRED A BILIARY PHENOTYPE, AND SUBSEQUENTLY FORMED BILE DUCTS ALONG THE HILUM-TO-PERIPHERY AXIS. IN DPPIV-CHIMERIC LIVER MODEL, PERIPORTAL HEPATOCYTES EXPRESSING HEPATOCYTE NUCLEAR FACTOR-1BETA (HNF-1BETA) WERE EXCLUSIVELY DPPIV-POSITIVE AND WERE IN CONTINUITY TO DPPIV-POSITIVES BILE DUCTS. INHIBITION OF HEPATOCYTE PROLIFERATION BY ADDITIONAL DOSES OF RETRORSINE IN DPPIV-CHIMERIC LIVERS PREVENTED THE APPEARANCE OF DPPIV-POSITIVE BECS AFTER BILIARY INJURY. MOREOVER, ENRICHED DPPIV-POSITIVE BEC/HEPATIC OVAL CELL TRANSPLANTATION PRODUCED DPPIV-POSITIVE BECS OR BILE DUCTS IN UNEXPECTEDLY LOW FREQUENCY AND IN MID-LOBULAR REGIONS. THESE RESULTS TOGETHER SUGGEST THAT MATURE HEPATOCYTES BUT NOT CONTAMINATING BECS/HEPATIC OVAL CELLS ARE THE SOURCES OF PERIPORTAL DPPIV-POSITIVE BECS. WE CONCLUDE THAT MATURE HEPATOCYTES CONTRIBUTE TO BILIARY REGENERATION IN THE ENVIRONMENT OF ACUTE AND CHRONIC BILIARY INJURY THROUGH A DUCTAL PLATE CONFIGURATION WITHOUT THE NEED OF EXOGENOUSLY GENETIC OR EPIGENETIC MANIPULATION. 2015 15 6509 28 TRANSCRIPTION FACTOR RFX1 IS UBIQUITINATED BY E3 LIGASE STUB1 IN SYSTEMIC LUPUS ERYTHEMATOSUS. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IS A CHRONIC AUTOIMMUNE DISEASE CAUSED BY COMPLEX INTERACTIONS BETWEEN GENES AND THE ENVIRONMENT. THE EXPRESSION LEVEL OF TRANSCRIPTION FACTOR REGULATORY FACTOR X 1 (RFX1) IS REDUCED IN T CELLS FROM SLE PATIENTS. RFX1 CAN REGULATE EPIGENETIC MODIFICATIONS OF CD70 AND CD11A AND PLAYS AN IMPORTANT ROLE IN THE DEVELOPMENT OF SLE. HOWEVER, THE MECHANISMS THAT MEDIATE REDUCTION OF RFX1 IN SLE ARE UNCLEAR. HERE, WE DEMONSTRATE THAT RFX1 PROTEIN EXPRESSION CAN BE TIGHTLY REGULATED BY POLYUBIQUITINATION-MEDIATED PROTEOSOMAL DEGRADATION VIA STIP1 HOMOLOGY AND U-BOX CONTAINING PROTEIN 1 (STUB1). THE E3 LIGASE STUB1 IS UPREGULATED IN CD4(+)T CELLS OF SLE PATIENTS COMPARED TO HEALTHY SUBJECTS. OVEREXPRESSION OF STUB1 IN CD4(+)T CELLS LEADS TO UPREGULATION OF LEVELS OF CD70 AND CD11A IN T CELLS. THE MODULATION OF STUB1 ACTIVITY MAY PROVIDE A NOVEL THERAPEUTIC APPROACH FOR SLE. 2016 16 481 22 ARSENIC-INDUCED SUMOYLATION OF MUS81 IS INVOLVED IN REGULATING GENOMIC STABILITY. CHRONIC ENVIRONMENTAL EXPOSURE TO METAL TOXICANTS SUCH AS CHROMIUM AND ARSENIC IS CLOSELY RELATED TO THE DEVELOPMENT OF SEVERAL TYPES OF COMMON CANCERS. GENETIC AND EPIGENETIC STUDIES IN THE PAST DECADE REVEAL THAT POST-TRANSLATIONAL MODIFICATIONS OF HISTONES PLAY A ROLE IN METAL CARCINOGENESIS. HOWEVER, EXACT MOLECULAR MECHANISMS OF METAL CARCINOGENESIS REMAIN TO BE ELUCIDATED. IN THIS STUDY WE FOUND THAT AS(2)O(3), AN ENVIRONMENTAL METAL TOXICANT, UPREGULATED OVERALL MODIFICATIONS OF MANY CELLULAR PROTEINS BY SUMO2/3. SUMOYLATED PROTEINS FROM ARSENIC-TREATED CELLS CONSTITUTIVELY EXPRESSING HIS(6)-SUMO2 WERE PULLED DOWN BY NI-IDA RESIN UNDER DENATURING CONDITIONS. MASS SPECTROMETRIC ANALYSIS REVEALED OVER 100 PROTEINS THAT WERE POTENTIALLY MODIFIED BY SUMOYLATION. MUS81, A DNA ENDONUCLEASE INVOLVED IN HOMOLOGOUS RECOMBINATION REPAIR, WAS AMONG THE IDENTIFIED PROTEINS WHOSE SUMOYLATION WAS INCREASED AFTER TREATMENT WITH AS(2)O(3.) WE FURTHER SHOWED THAT K10 AND K524 WERE 2 LYSINE RESIDUES ESSENTIAL FOR MUS81 SUMOYLATION. MOREOVER, WE DEMONSTRATED THAT MUS81 SUMOYLATION IS IMPORTANT FOR NORMAL MITOTIC CHROMOSOME CONGRESSION AND THAT CELLS EXPRESSING SUMO-RESISTANT MUS81 MUTANTS DISPLAYED COMPROMISED DNA DAMAGE RESPONSES AFTER EXPOSURE TO METAL TOXINS SUCH AS CR(VI) AND ARSENIC. 2017 17 2887 26 GADD45A TRANSCRIPTIONAL INDUCTION ELICITED BY THE AURORA KINASE INHIBITOR MK-0457 IN BCR-ABL-EXPRESSING CELLS IS DRIVEN BY OCT-1 TRANSCRIPTION FACTOR. THE ADVANTAGE OF AURORA KINASE (AK) INHIBITORS IN CHRONIC MYELOID LEUKEMIA (CML) THERAPY MOSTLY ARISES FROM "OFF-TARGET" EFFECTS ON TYROSINE KINASE (TK) ACTIVITY OF WILD TYPE (WT) OR MUTATED BCR-ABL PROTEINS WHICH DRIVE THE DISEASE RESISTANCE TO IMATINIB (IM). WE PROVED THAT THE AK INHIBITOR MK-0457 INDUCES THE GROWTH ARREST DNA DAMAGE-INDUCIBLE (GADD) 45A THROUGH RECRUITMENT OF OCTAMER-BINDING (OCT)-1 TRANSCRIPTION FACTOR AT A CRITICAL PROMOTER REGION FOR GENE TRANSCRIPTION AND COVALENT MODIFICATIONS OF HISTONE H3 (LYSINE 14 ACETYLATION, LYSINE 9 DE-METHYLATION). SUCH EPIGENETIC CHROMATIN MODIFICATIONS MAY DEPICT A GENERAL MECHANISM PROMOTING THE RE-ACTIVATION OF TUMOR SUPPRESSOR GENES SILENCED BY BCR-ABL. 2012 18 2867 20 FUNCTIONAL AND CANCER GENOMICS OF ASXL FAMILY MEMBERS. ADDITIONAL SEX COMBS-LIKE (ASXL)1, ASXL2 AND ASXL3 ARE HUMAN HOMOLOGUES OF THE DROSOPHILA ASX GENE THAT ARE INVOLVED IN THE REGULATION OR RECRUITMENT OF THE POLYCOMB-GROUP REPRESSOR COMPLEX (PRC) AND TRITHORAX-GROUP (TRXG) ACTIVATOR COMPLEX. ASXL PROTEINS CONSIST OF ASXN, ASXH, ASXM1, ASXM2 AND PHD DOMAINS. ASXL1 DIRECTLY INTERACTS WITH BAP1, KDM1A (LSD1), NCOA1 AND NUCLEAR HORMONE RECEPTORS (NHRS), SUCH AS RETINOIC ACID RECEPTORS, OESTROGEN RECEPTOR AND ANDROGEN RECEPTOR. ASXL FAMILY MEMBERS ARE EPIGENETIC SCAFFOLDING PROTEINS THAT ASSEMBLE EPIGENETIC REGULATORS AND TRANSCRIPTION FACTORS TO SPECIFIC GENOMIC LOCI WITH HISTONE MODIFICATIONS. ASXL1 IS INVOLVED IN TRANSCRIPTIONAL REPRESSION THROUGH AN INTERACTION WITH PRC2 AND ALSO CONTRIBUTES TO TRANSCRIPTIONAL REGULATION THROUGH INTERACTIONS WITH BAP1 AND/OR NHR COMPLEXES. GERM-LINE MUTATIONS OF HUMAN ASXL1 AND ASXL3 OCCUR IN BOHRING-OPITZ AND RELATED SYNDROMES. AMPLIFICATION AND OVEREXPRESSION OF ASXL1 OCCUR IN CERVICAL CANCER. TRUNCATION MUTATIONS OF ASXL1 OCCUR IN COLORECTAL CANCERS WITH MICROSATELLITE INSTABILITY (MSI), MALIGNANT MYELOID DISEASES, CHRONIC LYMPHOCYTIC LEUKAEMIA, HEAD AND NECK SQUAMOUS CELL CARCINOMA, AND LIVER, PROSTATE AND BREAST CANCERS; THOSE OF ASXL2 OCCUR IN PROSTATE CANCER, PANCREATIC CANCER AND BREAST CANCER AND THOSE OF ASXL3 ARE OBSERVED IN MELANOMA. EPC1-ASXL2 GENE FUSION OCCURS IN ADULT T-CELL LEUKAEMIA/LYMPHOMA. THE PROGNOSIS OF MYELOID MALIGNANCIES WITH MISREGULATING TRUNCATION MUTATIONS OF ASXL1 IS POOR. ASXL FAMILY MEMBERS ARE ASSUMED TO BE TUMOUR SUPPRESSIVE OR ONCOGENIC IN A CONTEXT-DEPENDENT MANNER. 2013 19 3249 25 HEPATITIS B VIRUS HIJACKS CTHRC1 TO EVADE HOST IMMUNITY AND MAINTAIN REPLICATION. HEPATITIS B VIRUS (HBV) INFECTION CAUSES ACUTE AND CHRONIC LIVER DISEASES, BUT IS NOT DIRECTLY CYTOPATHIC. LIVER INJURY RESULTS FROM REPEATED ATTEMPTS OF THE CELLULAR IMMUNE RESPONSE SYSTEM TO CONTROL THE VIRAL INFECTION. HERE, WE INVESTIGATE THE ROLES OF CELLULAR FACTORS AND SIGNALING PATHWAYS INVOLVED IN THE REGULATION OF HBV REPLICATION TO REVEAL THE MECHANISM UNDERLYING HBV INFECTION AND PATHOGENESIS. WE SHOW THAT COLLAGEN TRIPLE HELIX REPEAT CONTAINING 1 (CTHRC1) EXPRESSION IS ELEVATED IN HBV-INFECTED PATIENTS AND IN HBV-TRANSFECTED CELLS THROUGH EPIGENETIC MODIFICATION AND TRANSCRIPTIONAL REGULATION. CTHRC1 FACILITATES HBV REPLICATION IN CULTURED CELLS AND BALB/C MICE BY ACTIVATING THE PKCALPHA/ERK/JNK/C-JUN CASCADE TO REPRESS THE IFN/JAK/STAT PATHWAY. HBV-ACTIVATED CTHRC1 DOWNREGULATES THE ACTIVITY OF TYPE I INTERFERON (IFN), THE PRODUCTION OF IFN-STIMULATED GENES (ISGS), AND THE PHOSPHORYLATION OF SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION 1/2 (STAT1/2), WHEREAS IT UPREGULATES THE PHOSPHORYLATION AND UBIQUITINATION OF TYPE I IFN RECEPTORS (IFNARALPHA/BETA). THUS, OUR RESULTS SHOW THAT HBV USES A NOVEL MECHANISM TO HIJACK CELLULAR FACTORS AND SIGNAL CASCADES IN ORDER TO EVADE HOST ANTIVIRAL IMMUNITY AND MAINTAIN PERSISTENT INFECTION. WE ALSO DEMONSTRATE THAT CTHRC1 HAS A NOVEL ROLE IN VIRAL INFECTION. 2015 20 2316 27 EPIGENETIC REGULATION OF FRUCTOSE-1,6-BISPHOSPHATASE 1 BY HOST TRANSCRIPTION FACTOR SPECKLED 110 KDA DURING HEPATITIS B VIRUS INFECTION. HEPATITIS B VIRUS (HBV) IS THE LEADING CAUSE OF LIVER DISEASE RANGING FROM ACUTE AND CHRONIC HEPATITIS TO LIVER CIRRHOSIS AND HEPATOCELLULAR CARCINOMA (HCC). STUDIES HAVE REVEALED THAT HBV INFECTION BROADLY REPROGRAMMES THE HOST CELLULAR METABOLIC PROCESSES FOR VIRAL PATHOGENESIS. PREVIOUS REPORTS HAVE SHOWN THAT GLYCOLYSIS AND GLUCONEOGENESIS ARE AMONG THE MOST DEREGULATED PATHWAYS DURING HBV INFECTION. WE NOTED THAT DESPITE BEING ONE OF THE RATE-LIMITING ENZYMES OF GLUCONEOGENESIS, THE ROLE AND REGULATION OF FRUCTOSE-1,6-BISPHOSPHATASE 1 (FBP1) DURING HBV INFECTION IS NOT MUCH EXPLORED. IN THIS STUDY, WE REPORT FBP1 UPREGULATION UPON HBV INFECTION AND UNRAVEL A NOVEL MECHANISM OF EPIGENETIC REPROGRAMMING OF FBP1 BY HBV VIA UTILIZING HOST FACTOR SPECKLED 110 KDA (SP110). HERE, WE IDENTIFIED ACETYLATED LYSINE 18 OF HISTONE H3 (H3K18AC) AS A SELECTIVE INTERACTOR OF SP110 BROMODOMAIN. FURTHERMORE, WE FOUND THAT SP110 GETS RECRUITED ON H3K18AC-ENRICHED FBP1 PROMOTER, AND FACILITATES RECRUITMENT OF DEACETYLASE SIRTUIN 2 (SIRT2) ON THAT SITE IN THE PRESENCE OF HBV. SIRT2 IN TURN BRINGS ITS INTERACTOR AND TRANSCRIPTIONAL ACTIVATOR HEPATOCYTE NUCLEAR FACTOR 4-ALPHA TO THE PROMOTER, WHICH ULTIMATELY LEADS TO A LOSS OF DNA METHYLATION NEAR THE COGNATE SITE. INTERESTINGLY, THIS SP110 DRIVEN FBP1 REGULATION DURING INFECTION WAS FOUND TO PROMOTE VIRAL-BORNE HCC PROGRESSION. MOREOVER, SP110 CAN BE USED AS A PROGNOSTIC MARKER FOR THE HEPATITIS-MEDIATED HCC PATIENTS, WHERE HIGH SP110 EXPRESSION SIGNIFICANTLY LOWERED THEIR SURVIVAL. THUS, THE EPIGENETIC READER PROTEIN SP110 HAS POTENTIAL TO BE A THERAPEUTIC TARGET TO CHALLENGE HBV-INDUCED HCCS. 2022