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 1652 38 DOPAMINE SIGNALING LEADS TO LOSS OF POLYCOMB REPRESSION AND ABERRANT GENE ACTIVATION IN EXPERIMENTAL PARKINSONISM. POLYCOMB GROUP (PCG) PROTEINS BIND TO AND REPRESS GENES IN EMBRYONIC STEM CELLS THROUGH LINEAGE COMMITMENT TO THE TERMINAL DIFFERENTIATED STATE. PCG REPRESSED GENES ARE COMMONLY CHARACTERIZED BY THE PRESENCE OF THE EPIGENETIC HISTONE MARK H3K27ME3, CATALYZED BY THE POLYCOMB REPRESSIVE COMPLEX 2. HERE, WE PRESENT IN VIVO EVIDENCE FOR A PREVIOUSLY UNRECOGNIZED PLASTICITY OF PCG-REPRESSED GENES IN TERMINALLY DIFFERENTIATED BRAIN NEURONS OF PARKISONIAN MICE. WE SHOW THAT ACUTE ADMINISTRATION OF THE DOPAMINE PRECURSOR, L-DOPA, INDUCES A REMARKABLE INCREASE IN H3K27ME3S28 PHOSPHORYLATION. THE INDUCTION OF THE H3K27ME3S28P HISTONE MARK SPECIFICALLY OCCURS IN MEDIUM SPINY NEURONS EXPRESSING DOPAMINE D1 RECEPTORS AND IS DEPENDENT ON MSK1 KINASE ACTIVITY AND DARPP-32-MEDIATED INHIBITION OF PROTEIN PHOSPHATASE-1. CHROMATIN IMMUNOPRECIPITATION (CHIP) EXPERIMENTS SHOWED THAT INCREASED H3K27ME3S28P WAS ACCOMPANIED BY REDUCED PCG BINDING TO REGULATORY REGIONS OF GENES. AN ANALYSIS OF THE GENOME WIDE DISTRIBUTION OF L-DOPA-INDUCED H3K27ME3S28 PHOSPHORYLATION BY CHIP SEQUENCING (CHIP-SEQ) IN COMBINATION WITH EXPRESSION ANALYSIS BY RNA-SEQUENCING (RNA-SEQ) SHOWED THAT THE INDUCTION OF H3K27ME3S28P CORRELATED WITH INCREASED EXPRESSION OF A SUBSET OF PCG REPRESSED GENES. WE FOUND THAT INDUCTION OF H3K27ME3S28P PERSISTED DURING CHRONIC L-DOPA ADMINISTRATION TO PARKISONIAN MICE AND CORRELATED WITH ABERRANT GENE EXPRESSION. WE PROPOSE THAT DOPAMINERGIC TRANSMISSION CAN ACTIVATE PCG REPRESSED GENES IN THE ADULT BRAIN AND THEREBY CONTRIBUTE TO LONG-TERM MALADAPTIVE RESPONSES INCLUDING THE MOTOR COMPLICATIONS, OR DYSKINESIA, CAUSED BY PROLONGED ADMINISTRATION OF L-DOPA IN PARKINSON'S DISEASE. 2014 3 3658 30 INDUCTION OF ABERRANT TRIMETHYLATION OF HISTONE H3 LYSINE 27 BY INFLAMMATION IN MOUSE COLONIC EPITHELIAL CELLS. A FIELD FOR CANCERIZATION (FIELD DEFECT), WHERE GENETIC AND EPIGENETIC ALTERATIONS ARE ACCUMULATED IN NORMAL-APPEARING TISSUES, IS INVOLVED IN HUMAN CARCINOGENESIS, ESPECIALLY CANCERS ASSOCIATED WITH CHRONIC INFLAMMATION. ALTHOUGH ABERRANT DNA METHYLATION IS INVOLVED IN THE FIELD DEFECT AND INDUCED BY CHRONIC INFLAMMATION, IT IS STILL UNCLEAR FOR TRIMETHYLATION OF HISTONE H3 LYSINE 27 (H3K27ME3), WHICH IS INVOLVED IN GENE REPRESSION INDEPENDENT OF DNA METHYLATION AND FUNCTIONS AS A PRE-MARK FOR ABERRANT DNA METHYLATION. IN THIS STUDY, USING A MOUSE COLITIS MODEL INDUCED BY DEXTRAN SULFATE SODIUM (DSS), WE AIMED TO CLARIFY WHETHER ABERRANT H3K27ME3 IS INDUCED BY INFLAMMATION AND INVOLVED IN A FIELD DEFECT. CHIP-ON-CHIP ANALYSIS OF COLONIC EPITHELIAL CELLS REVEALED THAT H3K27ME3 LEVELS WERE INCREASED OR DECREASED FOR 266 GENOMIC REGIONS BY AGING, AND MORE EXTENSIVELY (23 INCREASED AND 3574 DECREASED REGIONS) BY COLITIS. SUCH INCREASE OR DECREASE OF H3K27ME3 WAS INDUCED AS EARLY AS 2 WEEKS AFTER THE INITIATION OF DSS TREATMENT, AND PERSISTED AT LEAST FOR 16 WEEKS EVEN AFTER THE INFLAMMATION DISAPPEARED. SOME OF THE ABERRANT H3K27ME3 IN COLONIC EPITHELIAL CELLS WAS CARRIED OVER INTO COLON TUMORS. FURTHERMORE, H3K27ME3 ACQUIRED AT DAPK1 BY COLITIS WAS FOLLOWED BY INCREASED DNA METHYLATION, SUPPORTING ITS FUNCTION AS A PRE-MARK FOR ABERRANT DNA METHYLATION. THESE RESULTS DEMONSTRATED THAT ABERRANT H3K27ME3 CAN BE INDUCED BY EXPOSURE TO A SPECIFIC ENVIRONMENT, SUCH AS COLITIS, AND SUGGESTED THAT ABERRANT HISTONE MODIFICATION, IN ADDITION TO ABERRANT DNA METHYLATION, IS INVOLVED IN THE FORMATION OF A FIELD DEFECT. 2012 4 2370 30 EPIGENETIC REGULATION OF THE ALTERNATIVELY ACTIVATED MACROPHAGE PHENOTYPE. ALTERNATIVELY ACTIVATED (M2) MACROPHAGES PLAY CRITICAL ROLES IN DIVERSE CHRONIC DISEASES, INCLUDING PARASITE INFECTIONS, CANCER, AND ALLERGIC RESPONSES. HOWEVER, LITTLE IS KNOWN ABOUT THE ACQUISITION AND MAINTENANCE OF THEIR PHENOTYPE. WE REPORT THAT M2-MACROPHAGE MARKER GENES ARE EPIGENETICALLY REGULATED BY RECIPROCAL CHANGES IN HISTONE H3 LYSINE-4 (H3K4) AND HISTONE H3 LYSINE-27 (H3K27) METHYLATION; AND THE LATTER METHYLATION MARKS ARE REMOVED BY THE H3K27 DEMETHYLASE JUMONJI DOMAIN CONTAINING 3 (JMJD3). WE FOUND THAT CONTINUOUS INTERLEUKIN-4 (IL-4) TREATMENT LEADS TO DECREASED H3K27 METHYLATION, AT THE PROMOTER OF M2 MARKER GENES, AND A CONCOMITANT INCREASE IN JMJD3 EXPRESSION. FURTHERMORE, WE DEMONSTRATE THAT IL-4-DEPENDENT JMJD3 EXPRESSION IS MEDIATED BY STAT6, A MAJOR TRANSCRIPTION FACTOR OF IL-4-MEDIATED SIGNALING. AFTER IL-4 STIMULATION, ACTIVATED STAT6 IS INCREASED AND BINDS TO CONSENSUS SITES AT THE JMJD3 PROMOTER. INCREASED JMJD3 CONTRIBUTES TO THE DECREASE OF H3K27 DIMETHYLATION AND TRIMETHYLATION (H3K27ME2/3) MARKS AS WELL AS THE TRANSCRIPTIONAL ACTIVATION OF SPECIFIC M2 MARKER GENES. THE DECREASE IN H3K27ME2/3 AND INCREASE IN JMJD3 RECRUITMENT WERE CONFIRMED BY IN VIVO STUDIES USING A SCHISTOSOMA MANSONI EGG-CHALLENGED MOUSE MODEL, A WELL-STUDIED SYSTEM KNOWN TO SUPPORT AN M2 PHENOTYPE. COLLECTIVELY, THESE DATA INDICATE THAT CHROMATIN REMODELING IS MECHANISTICALLY IMPORTANT IN THE ACQUISITION OF THE M2-MACROPHAGE PHENOTYPE. 2009 5 5972 24 TET REPRESSION AND INCREASED DNMT ACTIVITY SYNERGISTICALLY INDUCE ABERRANT DNA METHYLATION. CHRONIC INFLAMMATION IS DEEPLY INVOLVED IN VARIOUS HUMAN DISORDERS, SUCH AS CANCER, NEURODEGENERATIVE DISORDERS, AND METABOLIC DISORDERS. INDUCTION OF EPIGENETIC ALTERATIONS, ESPECIALLY ABERRANT DNA METHYLATION, IS ONE OF THE MAJOR MECHANISMS, BUT HOW IT IS INDUCED IS STILL UNCLEAR. HERE, WE FOUND THAT EXPRESSION OF TET GENES, METHYLATION ERASERS, WAS DOWNREGULATED IN INFLAMED MOUSE AND HUMAN TISSUES, AND THAT THIS WAS CAUSED BY UPREGULATION OF TET-TARGETING MIRNAS SUCH AS MIR20A, MIR26B, AND MIR29C, LIKELY DUE TO ACTIVATION OF NF-KAPPAB SIGNALING DOWNSTREAM OF IL-1BETA AND TNF-ALPHA. HOWEVER, TET KNOCKDOWN INDUCED ONLY MILD ABERRANT METHYLATION. NITRIC OXIDE (NO), PRODUCED BY NOS2, ENHANCED ENZYMATIC ACTIVITY OF DNA METHYLTRANSFERASES (DNMTS), METHYLATION WRITERS, AND NO EXPOSURE INDUCED MINIMAL ABERRANT METHYLATION. IN CONTRAST, A COMBINATION OF TET KNOCKDOWN AND NO EXPOSURE SYNERGISTICALLY INDUCED ABERRANT METHYLATION, INVOLVING GENOMIC REGIONS NOT METHYLATED BY EITHER ALONE. THE RESULTS SHOWED THAT A VICIOUS COMBINATION OF TET REPRESSION, DUE TO NF-KAPPAB ACTIVATION, AND DNMT ACTIVATION, DUE TO NO PRODUCTION, IS RESPONSIBLE FOR ABERRANT METHYLATION INDUCTION IN HUMAN TISSUES. 2020 6 2055 25 EPIGENETIC CONTROL DURING LYMPHOID DEVELOPMENT AND IMMUNE RESPONSES: ABERRANT REGULATION, VIRUSES, AND CANCER. METHYLATION OF CYTOSINES CONTROLS A NUMBER OF BIOLOGIC PROCESSES SUCH AS IMPRINTING AND X CHROMOSOMAL INACTIVATION. DNA HYPERMETHYLATION IS CLOSELY ASSOCIATED WITH TRANSCRIPTIONAL SILENCING, WHILE DNA HYPOMETHYLATION IS ASSOCIATED WITH TRANSCRIPTIONAL ACTIVATION. HYPOACETYLATION OF HISTONES LEADS TO COMPACT CHROMATIN WITH REDUCED ACCESSIBILITY TO THE TRANSCRIPTIONAL MACHINERY. METHYL-CPG BINDING PROTEINS CAN RECRUIT COREPRESSORS AND HISTONE DEACETYLASES; THUS, THE INTERPLAY BETWEEN THESE EPIGENETIC MECHANISMS REGULATES GENE ACTIVATION. METHYLATION HAS BEEN IMPLICATED AS AN IMPORTANT MECHANISM DURING IMMUNE DEVELOPMENT, CONTROLLING VDJ RECOMBINATION, LINEAGE-SPECIFIC EXPRESSION OF CELL SURFACE ANTIGENS, AND TRANSCRIPTIONAL REGULATION OF CYTOKINE GENES DURING IMMUNE RESPONSES. ABERRATIONS IN EPIGENETIC MACHINERY, EITHER BY GENETIC MUTATIONS OR BY SOMATIC CHANGES SUCH AS VIRAL INFECTIONS, ARE ASSOCIATED WITH EARLY ALTERATIONS IN CHRONIC DISEASES SUCH AS IMMUNODEFICIENCY AND CANCER. 2003 7 3527 27 IL-6 ENHANCES THE NUCLEAR TRANSLOCATION OF DNA CYTOSINE-5-METHYLTRANSFERASE 1 (DNMT1) VIA PHOSPHORYLATION OF THE NUCLEAR LOCALIZATION SEQUENCE BY THE AKT KINASE. THE EPIGENETIC PROGRAMMING OF GENOMIC DNA IS ACCOMPLISHED, IN PART, BY SEVERAL DNA CYTOSINE-5-METHYLTRANSFERASES THAT ACT BY COVALENTLY MODIFYING CYTOSINES WITH THE ADDITION OF A METHYL GROUP. THIS COVALENT MODIFICATION IS MAINTAINED BY THE DNA CYTOSINE-5-METHYLTRANSFERASE-1 ENZYME (DNMT1), WHICH IS CAPABLE OF ACTING IN CONCERT WITH OTHER SIMILAR ENZYMES TO SILENCE IMPORTANT TUMOR SUPPRESSOR GENES. IL-6 IS A MULTIFUNCTIONAL MEDIATOR OF INFLAMMATION, ACTING THROUGH SEVERAL MAJOR SIGNALING CASCADES, INCLUDING THE PHOSPHATIDYLINOSITOL-3-KINASE PATHWAY (PI-3-K), WHICH ACTIVATES PROTEIN KINASE B (AKT/PKB) DOWNSTREAM. HERE, WE SHOW THAT THE SUBCELLULAR LOCALIZATION OF DNMT1 CAN BE ALTERED BY THE ADDITION OF IL-6, INCREASING THE RATE OF NUCLEAR TRANSLOCATION OF THE ENZYME FROM THE CYTOSOLIC COMPARTMENT. THE MECHANISM OF NUCLEAR TRANSLOCATION OF DNMT1 IS GREATLY ENHANCED BY PHOSPHORYLATION OF THE DNMT1 NUCLEAR LOCALIZATION SIGNAL (NLS) BY PKB/AKT KINASE. MUTAGENIC ALTERATION OF THE TWO AKT TARGET AMINO ACIDS WITHIN THE NLS RESULTS IN A MAJOR LOSS OF DNMT1 NUCLEAR TRANSLOCATION, WHILE THE CREATION OF A "PHOSPHO-MIMIC" AMINO ACID (MUTATION TO ACIDIC RESIDUES) RESTORES THIS COMPARTMENTATION ABILITY. THESE OBSERVATIONS SUGGEST AN INTERESTING HYPOTHESIS REGARDING HOW MEDIATORS OF CHRONIC INFLAMMATION MAY DISTURB THE DELICATE BALANCE OF CELLULAR COMPARTMENTALIZATION OF IMPORTANT PROTEINS, AND REVEALS A POTENTIAL MECHANISM FOR THE INDUCTION OR ENHANCEMENT OF TUMOR GROWTH VIA ALTERATION OF THE COMPONENTS INVOLVED IN THE EPIGENETIC PROGRAMMING OF A CELL. 2007 8 4497 33 MORPHINE LEADS TO GLOBAL GENOME CHANGES IN H3K27ME3 LEVELS VIA A POLYCOMB REPRESSIVE COMPLEX 2 (PRC2) SELF-REGULATORY MECHANISM IN MESCS. BACKGROUND: ENVIRONMENTALLY INDUCED EPIGENETIC CHANGES CAN LEAD TO HEALTH PROBLEMS OR DISEASE, BUT THE MECHANISMS INVOLVED REMAIN UNCLEAR. MORPHINE CAN PASS THROUGH THE PLACENTAL BARRIER LEADING TO ABNORMAL EMBRYO DEVELOPMENT. HOWEVER, THE MECHANISM BY WHICH MORPHINE CAUSES THESE EFFECTS AND HOW THEY SOMETIMES PERSIST INTO ADULTHOOD IS NOT WELL KNOWN. TO UNRAVEL THE MORPHINE-INDUCED CHROMATIN ALTERATIONS INVOLVED IN ABERRANT EMBRYO DEVELOPMENT, WE EXPLORED THE ROLE OF THE H3K27ME3/PRC2 REPRESSIVE COMPLEX IN GENE EXPRESSION AND ITS TRANSMISSION ACROSS CELLULAR GENERATIONS IN RESPONSE TO MORPHINE. RESULTS: USING MOUSE EMBRYONIC STEM CELLS AS A MODEL SYSTEM, WE FOUND THAT CHRONIC MORPHINE TREATMENT INDUCES A GLOBAL DOWNREGULATION OF THE HISTONE MODIFICATION H3K27ME3. CONVERSELY, CHIP-SEQ SHOWED A REMARKABLE INCREASE IN H3K27ME3 LEVELS AT SPECIFIC GENOMIC SITES, PARTICULARLY PROMOTERS, DISRUPTING SELECTIVE TARGET GENES RELATED TO EMBRYO DEVELOPMENT, CELL CYCLE AND METABOLISM. THROUGH A SELF-REGULATORY MECHANISM, MORPHINE DOWNREGULATED THE TRANSCRIPTION OF PRC2 COMPONENTS RESPONSIBLE FOR H3K27ME3 BY ENRICHING HIGH H3K27ME3 LEVELS AT THE PROMOTER REGION. DOWNREGULATION OF PRC2 COMPONENTS PERSISTED FOR AT LEAST 48 H (4 CELL CYCLES) FOLLOWING MORPHINE REMOVAL, THOUGH PROMOTER H3K27ME3 LEVELS RETURNED TO CONTROL LEVELS. CONCLUSIONS: MORPHINE INDUCES TARGETING OF THE PRC2 COMPLEX TO SELECTED PROMOTERS, INCLUDING THOSE OF PRC2 COMPONENTS, LEADING TO CHARACTERISTIC CHANGES IN GENE EXPRESSION AND A GLOBAL REDUCTION IN H3K27ME3. FOLLOWING MORPHINE REMOVAL, ENHANCED PROMOTER H3K27ME3 LEVELS REVERT TO NORMAL SOONER THAN GLOBAL H3K27ME3 OR PRC2 COMPONENT TRANSCRIPT LEVELS. WE SUGGEST THAT H3K27ME3 IS INVOLVED IN INITIATING MORPHINE-INDUCED CHANGES IN GENE EXPRESSION, BUT NOT IN THEIR MAINTENANCE. MODEL OF POLYCOMB REPRESSIVE COMPLEX 2 (PRC2) AND H3K27ME3 ALTERATIONS INDUCED BY CHRONIC MORPHINE EXPOSURE. MORPHINE INDUCES H3K27ME3 ENRICHMENT AT PROMOTERS OF GENES ENCODING CORE MEMBERS OF THE PRC2 COMPLEX AND IS ASSOCIATED WITH THEIR TRANSCRIPTIONAL DOWNREGULATION. 2020 9 5872 25 SUSTAINED TNF-ALPHA STIMULATION LEADS TO TRANSCRIPTIONAL MEMORY THAT GREATLY ENHANCES SIGNAL SENSITIVITY AND ROBUSTNESS. TRANSCRIPTIONAL MEMORY ALLOWS CERTAIN GENES TO RESPOND TO PREVIOUSLY EXPERIENCED SIGNALS MORE ROBUSTLY. HOWEVER, WHETHER AND HOW THE KEY PROINFLAMMATORY CYTOKINE TNF-ALPHA MEDIATES TRANSCRIPTIONAL MEMORY ARE POORLY UNDERSTOOD. USING HEK293F CELLS AS A MODEL SYSTEM, WE REPORT THAT SUSTAINED TNF-ALPHA STIMULATION INDUCES TRANSCRIPTIONAL MEMORY DEPENDENT ON TET ENZYMES. THE HYPOMETHYLATED STATUS OF TRANSCRIPTIONAL REGULATORY REGIONS CAN BE INHERITED, FACILITATING NF-KAPPAB BINDING AND MORE ROBUST SUBSEQUENT ACTIVATION. A HIGH INITIAL METHYLATION LEVEL AND CPG DENSITY AROUND KAPPAB SITES ARE CORRELATED WITH THE FUNCTIONAL POTENTIAL OF TRANSCRIPTIONAL MEMORY MODULES. INTERESTINGLY, THE CALCB GENE, ENCODING THE PROVEN MIGRAINE THERAPEUTIC TARGET CGRP, EXHIBITS THE BEST TRANSCRIPTIONAL MEMORY. A NEIGHBORING PRIMATE-SPECIFIC ENDOGENOUS RETROVIRUS STIMULATES MORE RAPID, MORE STRONG, AND AT LEAST 100-FOLD MORE SENSITIVE CALCB INDUCTION IN SUBSEQUENT TNF-ALPHA STIMULATION. OUR STUDY REVEALS THAT TNF-ALPHA-MEDIATED TRANSCRIPTIONAL MEMORY IS GOVERNED BY ACTIVE DNA DEMETHYLATION AND GREATLY SENSITIZES MEMORY GENES TO MUCH LOWER DOSES OF INFLAMMATORY CUES. 2020 10 2442 27 EPIGENETIC STABILITY IN THE ADULT MOUSE CORTEX UNDER CONDITIONS OF PHARMACOLOGICALLY INDUCED HISTONE ACETYLATION. HISTONE ACETYLATION IS CONSIDERED A MAJOR EPIGENETIC PROCESS THAT AFFECTS BRAIN DEVELOPMENT AND SYNAPTIC PLASTICITY, AS WELL AS LEARNING AND MEMORY. THE TRANSCRIPTIONAL EFFECTORS AND MORPHOLOGICAL CHANGES RESPONSIBLE FOR PLASTICITY AS A RESULT OF LONG-TERM MODIFICATIONS TO HISTONE ACETYLATION ARE NOT FULLY UNDERSTOOD. TO THIS END, WE PHARMACOLOGICALLY INHIBITED HISTONE DEACETYLATION USING TRICHOSTATIN A IN ADULT (6-MONTH-OLD) MICE AND FOUND SIGNIFICANT INCREASES IN THE LEVELS OF THE ACETYLATED HISTONE MARKS H3LYS9, H3LYS14 AND H4LYS12. HIGH-RESOLUTION TRANSCRIPTOME ANALYSIS OF DIVERSE BRAIN REGIONS UNCOVERED FEW DIFFERENCES IN GENE EXPRESSION BETWEEN TREATED AND CONTROL ANIMALS, NONE OF WHICH WERE PLASTICITY RELATED. INSTEAD, AFTER INCREASED HISTONE ACETYLATION, WE DETECTED A LARGE NUMBER OF NOVEL TRANSCRIPTIONALLY ACTIVE REGIONS, WHICH CORRESPOND TO LONG NON-CODING RNAS (LNCRNAS). WE ALSO SURPRISINGLY FOUND NO SIGNIFICANT CHANGES IN DENDRITIC SPINE PLASTICITY IN LAYERS 1 AND 2/3 OF THE VISUAL CORTEX USING LONG-TERM IN VIVO TWO-PHOTON IMAGING. OUR RESULTS INDICATE THAT CHRONIC PHARMACOLOGICALLY INDUCED HISTONE ACETYLATION CAN BE DECOUPLED FROM GENE EXPRESSION AND INSTEAD, MAY POTENTIALLY EXERT A POST-TRANSCRIPTIONAL EFFECT THROUGH THE DIFFERENTIAL PRODUCTION OF LNCRNAS. 2016 11 1731 36 DYSREGULATION OF THE HISTONE DEMETHYLASE KDM6B IN ALCOHOL DEPENDENCE IS ASSOCIATED WITH EPIGENETIC REGULATION OF INFLAMMATORY SIGNALING PATHWAYS. EPIGENETIC ENZYMES OVERSEE LONG-TERM CHANGES IN GENE EXPRESSION BY INTEGRATING GENETIC AND ENVIRONMENTAL CUES. WHILE THERE ARE HUNDREDS OF ENZYMES THAT CONTROL HISTONE AND DNA MODIFICATIONS, THEIR POTENTIAL ROLES IN SUBSTANCE ABUSE AND ALCOHOL DEPENDENCE REMAIN UNDEREXPLORED. A FEW RECENT STUDIES HAVE SUGGESTED THAT EPIGENETIC PROCESSES COULD UNDERLIE TRANSCRIPTOMIC AND BEHAVIORAL HALLMARKS OF ALCOHOL ADDICTION. IN THE PRESENT STUDY, WE SOUGHT TO IDENTIFY EPIGENETIC ENZYMES IN THE BRAIN THAT ARE DYSREGULATED DURING PROTRACTED ABSTINENCE AS A CONSEQUENCE OF CHRONIC AND INTERMITTENT ALCOHOL EXPOSURE. THROUGH QUANTITATIVE MRNA EXPRESSION ANALYSIS OF OVER 100 EPIGENETIC ENZYMES, WE IDENTIFIED 11 THAT ARE SIGNIFICANTLY ALTERED IN ALCOHOL-DEPENDENT RATS COMPARED WITH CONTROLS. FOLLOW-UP STUDIES OF ONE OF THESE ENZYMES, THE HISTONE DEMETHYLASE KDM6B, SHOWED THAT THIS ENZYME EXHIBITS REGION-SPECIFIC DYSREGULATION IN THE PREFRONTAL CORTEX AND NUCLEUS ACCUMBENS OF ALCOHOL-DEPENDENT RATS. KDM6B WAS ALSO UPREGULATED IN THE HUMAN ALCOHOLIC BRAIN. UPREGULATION OF KDM6B PROTEIN IN ALCOHOL-DEPENDENT RATS WAS ACCOMPANIED BY A DECREASE OF TRIMETHYLATION LEVELS AT HISTONE H3, LYSINE 27 (H3K27ME3), CONSISTENT WITH THE KNOWN DEMETHYLASE SPECIFICITY OF KDM6B. SUBSEQUENT EPIGENETIC (CHROMATIN IMMUNOPRECIPITATION [CHIP]-SEQUENCING) ANALYSIS SHOWED THAT ALCOHOL-INDUCED CHANGES IN H3K27ME3 WERE SIGNIFICANTLY ENRICHED AT GENES IN THE IL-6 SIGNALING PATHWAY, CONSISTENT WITH THE WELL-CHARACTERIZED ROLE OF KDM6B IN MODULATION OF INFLAMMATORY RESPONSES. KNOCKDOWN OF KDM6B IN CULTURED MICROGLIAL CELLS DIMINISHED IL-6 INDUCTION IN RESPONSE TO AN INFLAMMATORY STIMULUS. OUR FINDINGS IMPLICATE A NOVEL KDM6B-MEDIATED EPIGENETIC SIGNALING PATHWAY INTEGRATED WITH INFLAMMATORY SIGNALING PATHWAYS THAT ARE KNOWN TO UNDERLIE THE DEVELOPMENT OF ALCOHOL ADDICTION. 2021 12 164 31 ABNORMAL HISTONE METHYLATION IS RESPONSIBLE FOR INCREASED VASCULAR ENDOTHELIAL GROWTH FACTOR 165A SECRETION FROM AIRWAY SMOOTH MUSCLE CELLS IN ASTHMA. VASCULAR ENDOTHELIAL GROWTH FACTOR (VEGF), A KEY ANGIOGENIC MOLECULE, IS ABERRANTLY EXPRESSED IN SEVERAL DISEASES INCLUDING ASTHMA WHERE IT CONTRIBUTES TO BRONCHIAL VASCULAR REMODELING AND CHRONIC INFLAMMATION. ASTHMATIC HUMAN AIRWAY SMOOTH MUSCLE CELLS HYPERSECRETE VEGF, BUT THE MECHANISM IS UNCLEAR. IN THIS STUDY, WE DEFINED THE MECHANISM IN HUMAN AIRWAY SMOOTH MUSCLE CELLS FROM NONASTHMATIC AND ASTHMATIC PATIENTS. WE FOUND THAT ASTHMATIC CELLS LACKED A REPRESSION COMPLEX AT THE VEGF PROMOTER, WHICH WAS PRESENT IN NONASTHMATIC CELLS. RECRUITMENT OF G9A, TRIMETHYLATION OF HISTONE H3 AT LYSINE 9 (H3K9ME3), AND A RESULTANT DECREASE IN RNA POLYMERASE II AT THE VEGF PROMOTER WAS CRITICAL TO REPRESSION OF VEGF SECRETION IN NONASTHMATIC CELLS. AT THE ASTHMATIC PROMOTER, H3K9ME3 WAS ABSENT BECAUSE OF FAILED RECRUITMENT OF G9A; RNA POLYMERASE II BINDING, IN ASSOCIATION WITH TATA-BINDING PROTEIN-ASSOCIATED FACTOR 1, WAS INCREASED; H3K4ME3 WAS PRESENT; AND SP1 BINDING WAS EXAGGERATED AND SUSTAINED. IN CONTRAST, DNA METHYLATION AND HISTONE ACETYLATION WERE SIMILAR IN ASTHMATIC AND NONASTHMATIC CELLS. THIS IS THE FIRST STUDY, TO OUR KNOWLEDGE, TO SHOW THAT AIRWAY CELLS IN ASTHMA HAVE ALTERED EPIGENETIC REGULATION OF REMODELING GENE(S). HISTONE METHYLATION AT GENES SUCH AS VEGF MAY BE AN IMPORTANT NEW THERAPEUTIC TARGET. 2012 13 2926 19 GENERATION OF AN EPIGENETIC SIGNATURE BY CHRONIC HYPOXIA IN PROSTATE CELLS. INCREASING LEVELS OF TISSUE HYPOXIA HAVE BEEN REPORTED AS A NATURAL FEATURE OF THE AGING PROSTATE GLAND AND MAY BE A RISK FACTOR FOR THE DEVELOPMENT OF PROSTATE CANCER. IN THIS STUDY, WE HAVE USED PWR-1E BENIGN PROSTATE EPITHELIAL CELLS AND AN EQUIVALENTLY AGED HYPOXIA-ADAPTED PWR-1E SUB-LINE TO IDENTIFY PHENOTYPIC AND EPIGENETIC CONSEQUENCES OF CHRONIC HYPOXIA IN PROSTATE CELLS. WE HAVE IDENTIFIED A SIGNIFICANTLY ALTERED CELLULAR PHENOTYPE IN RESPONSE TO CHRONIC HYPOXIA AS CHARACTERIZED BY INCREASED RECEPTOR-MEDIATED APOPTOTIC RESISTANCE, THE INDUCTION OF CELLULAR SENESCENCE, INCREASED INVASION AND THE INCREASED SECRETION OF IL-1 BETA, IL6, IL8 AND TNFALPHA CYTOKINES. IN ASSOCIATION WITH THESE PHENOTYPIC CHANGES AND THE ABSENCE OF HIF-1 ALPHA PROTEIN EXPRESSION, WE HAVE DEMONSTRATED SIGNIFICANT INCREASES IN GLOBAL LEVELS OF DNA METHYLATION AND H3K9 HISTONE ACETYLATION IN THESE CELLS, CONCOMITANT WITH THE INCREASED EXPRESSION OF DNA METHYLTRANSFERASE DMNT3B AND GENE-SPECIFIC CHANGES IN DNA METHYLATION AT KEY IMPRINTING LOCI. IN CONCLUSION, WE HAVE DEMONSTRATED A GENOME-WIDE ADJUSTMENT OF DNA METHYLATION AND HISTONE ACETYLATION UNDER CHRONIC HYPOXIC CONDITIONS IN THE PROSTATE. THESE EPIGENETIC SIGNATURES MAY REPRESENT AN ADDITIONAL MECHANISM TO PROMOTE AND MAINTAIN A HYPOXIC-ADAPTED CELLULAR PHENOTYPE WITH A POTENTIAL ROLE IN TUMOUR DEVELOPMENT. 2009 14 926 36 CHRONIC INFLAMMATION PATHWAY NF-KAPPAB COOPERATES WITH EPIGENETIC REPROGRAMMING TO DRIVE THE MALIGNANT PROGRESSION OF GLIOBLASTOMA. WITHOUT AN EFFECTIVE STRATEGY FOR TARGETED THERAPY, GLIOBLASTOMA IS STILL INCURABLE WITH A MEDIAN SURVIVAL OF ONLY 15 MONTHS. BOTH CHRONIC INFLAMMATION AND EPIGENETIC REPROGRAMMING ARE HALLMARKS OF CANCER. HOWEVER, THE MECHANISMS AND CONSEQUENCES OF THEIR COOPERATION IN GLIOBLASTOMA REMAIN UNKNOWN. HERE, WE DISCOVER THAT CHRONIC INFLAMMATION GOVERNS H3K27ME3 REPROGRAMMING IN GLIOBLASTOMA THROUGH THE CANONICAL NF-KAPPAB PATHWAY TO TARGET EZH2. BEING A CRUCIAL MEDIATOR OF CHRONIC INFLAMMATION, THE CANONICAL NF-KAPPAB SIGNALLING SPECIFICALLY DIRECTS THE EXPRESSION AND REDISTRIBUTION OF H3K27ME3 BUT NOT H3K4ME3, H3K9ME3 AND H3K36ME3. USING RNA-SEQ SCREENING TO FOCUS ON GENES ENCODING METHYLTRANSFERASES AND DEMETHYLASES OF HISTONE, WE IDENTIFY EZH2 AS A KEY METHYLTRANSFERASE TO CONTROL INFLAMMATION-TRIGGERED EPIGENETIC REPROGRAMMING IN GLIOMAGENESIS. MECHANISTICALLY, NF-KAPPAB SELECTIVELY DRIVES THE EXPRESSION OF EZH2 BY ACTIVATING ITS TRANSCRIPTION, CONSEQUENTLY RESULTING IN A GLOBAL CHANGE IN H3K27ME3 EXPRESSION AND DISTRIBUTION. FURTHERMORE, WE FIND THAT CO-ACTIVATION OF NF-KAPPAB AND EZH2 CONFERS THE POOREST CLINICAL OUTCOME, AND THAT THE RISK FOR GLIOBLASTOMA CAN BE ACCURATELY MOLECULARLY STRATIFIED BY NF-KAPPAB AND EZH2. IT IS NOTABLE THAT NF-KAPPAB CAN POTENTIALLY COOPERATE WITH EZH2 IN MORE THAN ONE WAY, AND MOST IMPORTANTLY, WE DEMONSTRATE A SYNERGISTIC EFFECT OF CANCER CELLS INDUCED BY COMBINATORY INHIBITION OF NF-KAPPAB AND EZH2, WHICH BOTH ARE FREQUENTLY OVER-ACTIVATED IN GLIOBLASTOMA. IN SUMMARY, WE UNCOVER A FUNCTIONAL COOPERATION BETWEEN CHRONIC INFLAMMATION AND EPIGENETIC REPROGRAMMING IN GLIOBLASTOMA, COMBINED TARGETING OF WHICH BY INHIBITORS GUARANTEED IN SAFETY AND AVAILABILITY FURNISHES A POTENT STRATEGY FOR EFFECTIVE TREATMENT OF THIS FATAL DISEASE. 2022 15 5975 31 TET1 IS AN IMPORTANT TRANSCRIPTIONAL ACTIVATOR OF TNFALPHA EXPRESSION IN MACROPHAGES. ACTIVATION OF MACROPHAGES AND OVEREXPRESSION OF TNFALPHA IS ASSOCIATED WITH THE PATHOGENESIS OF CHRONIC INFLAMMATORY DISEASES. HOWEVER, THE MECHANISMS LEADING TO TNFALPHA OVEREXPRESSION ARE STILL UNKNOWN. 5-METHYLOCYTOSINE (5-MC) IS AN EPIGENETIC MODIFICATION THAT IS ASSOCIATED WITH SILENCED GENES. RECENT STUDIES SHOWED THAT IT IS CONVERTED TO 5-HYDROXYLMETHYLOCYTOSINE (5-HMC) AND REACTIVATES GENE EXPRESSION THROUGH THE ACTION OF THE FAMILY OF TEN-ELEVEN-TRANSLOCATION (TET1-3) ENZYMES. IN THIS STUDY, WE SHOW THAT 5-HMC LEVELS ARE INCREASED GLOBALLY AND SPECIFICALLY IN THE TNFALPHA PROMOTER DURING THE DIFFERENTIATION OF MONOCYTES TO MACROPHAGES. IN ADDITION, THE LEVELS OF 5-HMC ARE INCREASED UPON LPS STIMULATION OF MACROPHAGES. FURTHERMORE, CRIPSR STABLE KNOCKOUT OF TET1 DECREASES THE EXPRESSION OF TNFALPHA AND OTHER PRO-INFLAMMATORY CYTOKINES. IN CONCLUSION, WE SHOWED THAT TET1 CONTRIBUTES TO THE ACTIVATION OF MACROPHAGES POSSIBLY THROUGH REGULATION OF 5-HYDROXYMETHYLATION IN THE PROMOTER OF PRO-INFLAMMATORY CYTOKINE GENES. THE TET1 ENZYME COULD BE A PROMISING THERAPEUTIC TARGET TO INHIBIT THE PERSISTENT INFLAMMATION CAUSED BY MACROPHAGES IN CHRONIC INFLAMMATORY DISEASES. 2019 16 2280 31 EPIGENETIC REGULATION IN DRUG ADDICTION. THE INTERACTION BETWEEN ENVIRONMENTAL SIGNALS AND GENES HAS NOW TAKEN ON A CLEAR MOLECULAR FORM AS DEMONSTRATED BY STABLE CHANGES IN CHROMATIN STRUCTURE. THESE CHANGES OCCUR THROUGH ACTIVATION OR REPRESSION OF SPECIFIC GENE PROGRAMMES BY A COMBINATION OF CHROMATIN REMODELLING, ACTIVATION AND ENZYMATIC MODIFICATION OF DNA AND HISTONES AS WELL AS NUCLEOSOMAL SUBUNIT EXCHANGE. RECENT RESEARCH INVESTIGATING THE MOLECULAR MECHANISMS CONTROLLING DRUG-INDUCED TRANSCRIPTIONAL, BEHAVIOURAL AND SYNAPTIC ACTIVITY HAS SHOWN A DIRECT ROLE FOR CHROMATIN REMODELLING--TERMED AS EPIGENETIC REGULATION--OF NEURONAL GENE PROGRAMMES AND SUBSEQUENT ADDICTIVE BEHAVIOUR ARISING FROM IT. RECENT DATA SUGGEST THAT REPEATED EXPOSURE TO CERTAIN DRUGS PROMOTES CHANGES IN LEVELS OF HISTONE ACETYLATION, PHOSPHORYLATION AND METHYLATION, TOGETHER WITH ALTERATIONS IN DNA METHYLATION LEVELS IN THE NEURONS OF THE BRAIN REWARD CENTRE, LOCALISED IN THE NUCLEUS ACCUMBENS (NAC) REGION OF THE LIMBIC SYSTEM. THE COMBINATION OF ACETYLATING, PHOSPHORYLATING AND METHYLATING H3 AND H4 HISTONE TAILS ALTER CHROMATIN COMPACTION THEREBY PROMOTING ALTERED LEVELS OF CELLULAR GENE EXPRESSION. HISTONE MODIFICATIONS, WHICH WEAKEN HISTONE INTERACTION WITH DNA OR THAT PROMOTE RECRUITMENT OF TRANSCRIPTIONAL ACTIVATING COMPLEXES, CORRELATE WITH PERMISSIVE GENE EXPRESSION. HISTONE DEACETYLATION, (WHICH STRENGTHEN HISTONE: DNA CONTACTS), OR HISTONE METHYLATION, (WHICH RECRUITS REPRESSIVE COMPLEXES TO CHROMATIN), PROMOTE A STATE OF TRANSCRIPTIONAL REPRESSION. USING ANIMAL MODELS, ACUTE COCAINE TREATMENT INCREASES H4 ACETYLATION AT ACUTELY REGULATED GENE PROMOTERS, WHEREAS H3 ACETYLATION APPEARS TO PREDOMINATE AT CHRONICALLY INDUCED PROMOTERS. CHRONIC COCAINE AND ALCOHOL TREATMENT ACTIVATE AND REPRESS MANY GENES SUCH AS FOSB, CDK5, AND BDNF, WHERE THEIR DYSREGULATION, AT THE CHROMATIN LEVEL, CONTRIBUTE TO THE DEVELOPMENT AND MAINTENANCE OF ADDICTION. FOLLOWING DRUG EXPOSURE, IT IS STILL UNKNOWN, HOWVER, HOW LONG THESE CHANGES IN CHROMATIN STRUCTURE PERSIST IN AFFECTING NEURONAL FUNCTION, BUT SOME DO SO FOR LIFE. 2012 17 2002 23 EPIGENETIC AND POST-TRANSCRIPTIONAL REPRESSION SUPPORT METABOLIC SUPPRESSION IN CHRONICALLY HYPOXIC GOLDFISH. GOLDFISH ENTER A HYPOMETABOLIC STATE TO SURVIVE CHRONIC HYPOXIA. WE RECENTLY DESCRIBED TISSUE-SPECIFIC CONTRIBUTIONS OF MEMBRANE LIPID COMPOSITION REMODELING AND MITOCHONDRIAL FUNCTION TO METABOLIC SUPPRESSION ACROSS DIFFERENT GOLDFISH TISSUES. HOWEVER, THE MOLECULAR AND ESPECIALLY EPIGENETIC FOUNDATIONS OF HYPOXIA TOLERANCE IN GOLDFISH UNDER METABOLIC SUPPRESSION ARE NOT WELL UNDERSTOOD. HERE WE SHOW THAT COMPONENTS OF THE MOLECULAR OXYGEN-SENSING MACHINERY ARE ROBUSTLY ACTIVATED ACROSS TISSUES IRRESPECTIVE OF HYPOXIA DURATION. INDUCTION OF GENE EXPRESSION OF ENZYMES INVOLVED IN DNA METHYLATION TURNOVER AND MICRORNA BIOGENESIS SUGGEST A ROLE FOR EPIGENETIC TRANSCRIPTIONAL AND POST-TRANSCRIPTIONAL SUPPRESSION OF GENE EXPRESSION IN THE HYPOXIA-ACCLIMATED BRAIN. CONVERSELY, MECHANISTIC TARGET OF RAPAMYCIN-DEPENDENT TRANSLATIONAL MACHINERY ACTIVITY IS NOT REDUCED IN LIVER AND WHITE MUSCLE, SUGGESTING THIS PATHWAY DOES NOT CONTRIBUTE TO LOWERING CELLULAR ENERGY EXPENDITURE. FINALLY, MOLECULAR EVIDENCE SUPPORTS PREVIOUSLY REPORTED CHRONIC HYPOXIA-DEPENDENT CHANGES IN MEMBRANE CHOLESTEROL, LIPID METABOLISM AND MITOCHONDRIAL FUNCTION VIA CHANGES IN TRANSCRIPTS INVOLVED IN CHOLESTEROL BIOSYNTHESIS, BETA-OXIDATION, AND MITOCHONDRIAL FUSION IN MULTIPLE TISSUES. OVERALL, THIS STUDY SHOWS THAT CHRONIC HYPOXIA ROBUSTLY INDUCES EXPRESSION OF OXYGEN-SENSING MACHINERY ACROSS TISSUES, INDUCES REPRESSIVE TRANSCRIPTIONAL AND POST-TRANSCRIPTIONAL EPIGENETIC MARKS ESPECIALLY IN THE CHRONIC HYPOXIA-ACCLIMATED BRAIN AND SUPPORTS A ROLE FOR MEMBRANE REMODELING AND MITOCHONDRIAL FUNCTION AND DYNAMICS IN PROMOTING METABOLIC SUPPRESSION. 2022 18 1618 29 DNA METHYLTRANSFERASE INHIBITORS INCREASE NOD-LIKE RECEPTOR ACTIVITY AND EXPRESSION IN A MONOCYTIC CELL LINE. BACKGROUND: THE INTRACELLULAR NOD-LIKE RECEPTOR (NLR) FAMILY OF PATHOGEN RECOGNITION RECEPTORS (PRRA) IS INVOLVED IN INITIATING THE INNATE IMMUNE RESPONSE OF WHICH NOD1 AND NOD2 ARE THE BEST-CHARACTERIZED MEMBERS. ABERRANT EXPRESSION OF NOD1 AND NOD2 HAS BEEN UNCOVERED IN A NUMBER OF CHRONIC INFLAMMATORY DISEASES, SUCH AS INFLAMMATORY BOWEL DISEASE AND RHEUMATOID ARTHRITIS. HOWEVER, THE MECHANISM UNDERLYING NOD1/NOD2 GENE EXPRESSION REGULATION IS STILL IN ITS INFANCY. EPIGENETIC MODIFICATIONS SUCH AS DNA METHYLATION AND HISTONE ACETYLATION REGULATE THE EXPRESSION OF GENES AND ALTERATIONS IN THEIR PATTERNS HAVE BEEN LINKED TO MANY INFLAMMATORY DISEASES. THIS STUDY INVESTIGATED WHETHER EPIGENETIC MODIFYING DRUGS AFFECT THE REGULATION OF NOD1/NOD2 ACTIVITY AND EXPRESSION. DNA METHYLTRANSFERASE INHIBITORS HAVE RECENTLY BEEN USED IN THE TREATMENT OF MYELODYSPLASTIC SYNDROME AND AS COMBINATION THERAPY IN CANCER BUT THE FULL EXTENT OF THEIR EFFECTS HAS NOT BEEN QUANTIFIED.METHODS: PHARMACOLOGICAL INHIBITION OF EPIGENETIC ENZYMES IN A HUMAN MONOCYTIC THP-1 CELL LINE WAS CARRIED OUT AND NOD1/NOD2 EXPRESSION AND PRO-INFLAMMATORY RESPONSES WERE QUANTIFIED.RESULTS: CELLS PRIMED WITH A DNA METHYLTRANSFERASE INHIBITOR (BUT NOT A HISTONE DEACETYLASE [HDAC] INHIBITOR) WERE FOUND TO BE CONSISTENTLY MORE RESPONSIVE TO NOD1/NOD2 STIMULATION AND HAD INCREASED BASAL EXPRESSION.CONCLUSION: THE NOVEL EXPERIMENTATION CARRIED OUT HERE SUGGESTS FOR THE FIRST TIME THAT NOD1/NOD2 RECEPTOR ACTIVITY AND EXPRESSION IN MONOCYTES ARE POSSIBLY REGULATED DIRECTLY BY DNA METHYLATION. 2022 19 5279 27 PROMOTER-SPECIFIC RELEVANCE OF HISTONE MODIFICATIONS INDUCED BY DEXAMETHASONE DURING THE REGULATION OF PRO-INFLAMMATORY MEDIATORS. GLUCOCORTICOSTEROIDS (GCS) ARE WIDELY USED TO TREAT DIFFERENT KINDS OF CHRONIC INFLAMMATORY AND IMMUNE DISEASES THROUGH TRANSCRIPTIONAL REGULATION OF INFLAMMATORY GENES. MODULATION OF GENE EXPRESSION BY GCS IS KNOWN TO OCCUR THROUGH DIVERSE MECHANISMS OF VARYING RELEVANCE TO SPECIFIC CLASSES OF GENES. EPIGENETIC MODIFICATIONS ARE INDEED A PIVOTAL REGULATORY FEATURE OF GLUCOCORTICOID RECEPTOR AND OTHER TRANSCRIPTION FACTORS. IN THIS STUDY, HISTONE POST-TRANSLATIONAL MODIFICATIONS WERE INVESTIGATED FOR THEIR INVOLVEMENT IN THE REGULATION OF SELECTED PRO-INFLAMMATORY GENES - EXPRESSED IN HUMAN MONOCYTE-DERIVED MACROPHAGES - IN RESPONSE TO TREATMENT WITH SYNTHETIC GC DEXAMETHASONE (DEX). WE SHOW THAT HISTONE TAIL ACETYLATION STATUS IS MODIFIED FOLLOWING DEX ADMINISTRATION, THROUGH DISTINCT AND ALTERNATIVE MECHANISMS AT THE PROMOTERS OF INTERLEUKIN-8 AND INTERLEUKIN-23. IN ADDITION TO HISTONE H3 ACETYLATION, OUR RESULTS DEMONSTRATE THAT H3 LYSINE 4 TRIMETHYLATION IS AFFECTED FOLLOWING DRUG TREATMENT. 2014 20 4004 27 LOSS OF THE POLYCOMB MARK FROM BIVALENT PROMOTERS LEADS TO ACTIVATION OF CANCER-PROMOTING GENES IN COLORECTAL TUMORS. IN COLON TUMORS, THE TRANSCRIPTION OF MANY GENES BECOMES DEREGULATED BY POORLY DEFINED EPIGENETIC MECHANISMS THAT HAVE BEEN STUDIED MAINLY IN ESTABLISHED CELL LINES. IN THIS STUDY, WE USED FROZEN HUMAN COLON TISSUES TO ANALYZE PATTERNS OF HISTONE MODIFICATION AND DNA CYTOSINE METHYLATION IN CANCER AND MATCHED NORMAL MUCOSA SPECIMENS. DNA METHYLATION IS STRONGLY TARGETED TO BIVALENT H3K4ME3- AND H3K27ME3-ASSOCIATED PROMOTERS, WHICH LOSE BOTH HISTONE MARKS AND ACQUIRE DNA METHYLATION. HOWEVER, WE FOUND THAT LOSS OF THE POLYCOMB MARK H3K27ME3 FROM BIVALENT PROMOTERS WAS ACCOMPANIED OFTEN BY ACTIVATION OF GENES ASSOCIATED WITH CANCER PROGRESSION, INCLUDING NUMEROUS STEM CELL REGULATORS, ONCOGENES, AND PROLIFERATION-ASSOCIATED GENES. INDEED, WE FOUND MANY OF THESE SAME GENES WERE ALSO ACTIVATED IN PATIENTS WITH ULCERATIVE COLITIS WHERE CHRONIC INFLAMMATION PREDISPOSES THEM TO COLON CANCER. BASED ON OUR FINDINGS, WE PROPOSE THAT A LOSS OF POLYCOMB REPRESSION AT BIVALENT GENES COMBINED WITH AN ENSUING SELECTION FOR TUMOR-DRIVING EVENTS PLAYS A MAJOR ROLE IN CANCER PROGRESSION. 2014