1 1012 111 CIGARETTE SMOKE INDUCES DISTINCT HISTONE MODIFICATIONS IN LUNG CELLS: IMPLICATIONS FOR THE PATHOGENESIS OF COPD AND LUNG CANCER. CIGARETTE SMOKE (CS)-MEDIATED OXIDATIVE STRESS INDUCES SEVERAL SIGNALING CASCADES, INCLUDING KINASES, WHICH RESULTS IN CHROMATIN MODIFICATIONS (HISTONE ACETYLATION/DEACETYLATION AND HISTONE METHYLATION/DEMETHYLATION). WE HAVE PREVIOUSLY REPORTED THAT CS INDUCES CHROMATIN REMODELING IN PRO-INFLAMMATORY GENE PROMOTERS; HOWEVER, THE UNDERLYING SITE-SPECIFIC HISTONE MARKS FORMED IN HISTONES H3 AND H4 DURING CS EXPOSURE IN LUNGS IN VIVO AND IN LUNG CELLS IN VITRO, WHICH CAN EITHER DRIVE GENE EXPRESSION OR REPRESSION, ARE NOT KNOWN. WE HYPOTHESIZE THAT CS EXPOSURE IN MOUSE AND HUMAN BRONCHIAL EPITHELIAL CELLS (H292) CAN CAUSE SITE-SPECIFIC POSTTRANSLATIONAL HISTONE MODIFICATIONS (PTMS) THAT MAY PLAY AN IMPORTANT ROLE IN THE PATHOGENESIS OF CS-INDUCED CHRONIC LUNG DISEASES. WE USED A BOTTOM-UP MASS SPECTROMETRY APPROACH TO IDENTIFY SOME POTENTIALLY NOVEL HISTONE MARKS, INCLUDING ACETYLATION, MONOMETHYLATION, AND DIMETHYLATION, IN SPECIFIC LYSINE AND ARGININE RESIDUES OF HISTONES H3 AND H4 IN MOUSE LUNGS AND H292 CELLS. WE FOUND THAT CS-INDUCED DISTINCT POSTTRANSLATIONAL HISTONE MODIFICATION PATTERNS IN HISTONE H3 AND HISTONE H4 IN LUNG CELLS, WHICH MAY BE CONSIDERED AS USABLE BIOMARKERS FOR CS-INDUCED CHRONIC LUNG DISEASES. THESE IDENTIFIED HISTONE MARKS (HISTONE H3 AND HISTONE H4) MAY PLAY AN IMPORTANT ROLE IN THE EPIGENETIC STATE DURING THE PATHOGENESIS OF SMOKING-INDUCED CHRONIC LUNG DISEASES, SUCH AS CHRONIC OBSTRUCTIVE PULMONARY DISEASE AND LUNG CANCER. 2014 2 2910 48 GENE EXPRESSION PROFILING OF EPIGENETIC CHROMATIN MODIFICATION ENZYMES AND HISTONE MARKS BY CIGARETTE SMOKE: IMPLICATIONS FOR COPD AND LUNG CANCER. CHROMATIN-MODIFYING ENZYMES MEDIATE DNA METHYLATION AND HISTONE MODIFICATIONS ON RECRUITMENT TO SPECIFIC TARGET GENE LOCI IN RESPONSE TO VARIOUS STIMULI. THE KEY ENZYMES THAT REGULATE CHROMATIN ACCESSIBILITY FOR MAINTENANCE OF MODIFICATIONS IN DNA AND HISTONES, AND FOR MODULATION OF GENE EXPRESSION PATTERNS IN RESPONSE TO CIGARETTE SMOKE (CS), ARE NOT KNOWN. WE HYPOTHESIZE THAT CS EXPOSURE ALTERS THE GENE EXPRESSION PATTERNS OF CHROMATIN-MODIFYING ENZYMES, WHICH THEN AFFECTS MULTIPLE DOWNSTREAM PATHWAYS INVOLVED IN THE RESPONSE TO CS. WE HAVE, THEREFORE, ANALYZED CHROMATIN-MODIFYING ENZYME PROFILES AND VALIDATED BY QUANTITATIVE REAL-TIME PCR (QPCR). WE ALSO PERFORMED IMMUNOBLOT ANALYSIS OF TARGETED HISTONE MARKS IN C57BL/6J MICE EXPOSED TO ACUTE AND SUBCHRONIC CS, AND OF LUNGS FROM NONSMOKERS, SMOKERS, AND PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). WE FOUND A SIGNIFICANT INCREASE IN EXPRESSION OF SEVERAL CHROMATIN MODIFICATION ENZYMES, INCLUDING DNA METHYLTRANSFERASES, HISTONE ACETYLTRANSFERASES, HISTONE METHYLTRANSFERASES, AND SET DOMAIN PROTEINS, HISTONE KINASES, AND UBIQUITINASES. OUR QPCR VALIDATION DATA REVEALED A SIGNIFICANT DOWNREGULATION OF DNMT1, DNMT3A, DNMT3B, HDAC2, HDAC4, HAT1, PRMT1, AND AURKB WE IDENTIFIED TARGETED CHROMATIN HISTONE MARKS (H3K56AC AND H4K12AC), WHICH ARE INDUCED BY CS. THUS CS-INDUCED GENOTOXIC STRESS DIFFERENTIALLY AFFECTS THE EXPRESSION OF EPIGENETIC MODULATORS THAT REGULATE TRANSCRIPTION OF TARGET GENES VIA DNA METHYLATION AND SITE-SPECIFIC HISTONE MODIFICATIONS. THIS MAY HAVE IMPLICATIONS IN DEVISING EPIGENETIC-BASED THERAPIES FOR COPD AND LUNG CANCER. 2016 3 4889 49 OXIDATIVE STRESS AND CHROMATIN REMODELING IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE AND SMOKING-RELATED DISEASES. SIGNIFICANCE: CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IS PREDOMINANTLY A TOBACCO SMOKE-TRIGGERED DISEASE WITH FEATURES OF CHRONIC LOW-GRADE SYSTEMIC INFLAMMATION AND AGING (INFLAMMAGING) OF THE LUNG ASSOCIATED WITH STEROID RESISTANCE INDUCED BY CIGARETTE SMOKE (CS)-MEDIATED OXIDATIVE STRESS. OXIDATIVE STRESS INDUCES VARIOUS KINASE SIGNALING PATHWAYS LEADING TO CHROMATIN MODIFICATIONS (HISTONE ACETYLATION/DEACETYLATION AND HISTONE METHYLATION/DEMETHYLATION) IN INFLAMMATION, SENESCENCE, AND STEROID RESISTANCE. RECENT ADVANCES: HISTONE MONO-, DI-, OR TRI-METHYLATION AT LYSINE RESIDUES RESULT IN EITHER GENE ACTIVATION (H3K4, H3K36, AND H3K79) OR REPRESSION (H3K9, H3K27, AND H3K20). CROSS-TALK OCCURS BETWEEN VARIOUS EPIGENETIC MARKS ON HISTONES AND DNA METHYLATION. BOTH CS AND OXIDANTS ALTER HISTONE ACETYLATION/DEACETYLATION AND METHYLATION/DEMETHYLATION LEADING TO ENHANCED PROINFLAMMATORY GENE EXPRESSION. CHROMATIN MODIFICATIONS OCCUR IN LUNGS OF PATIENTS WITH COPD. HISTONE DEACETYLASE 2 (HDAC2) REDUCTION (LEVELS AND ACTIVITY) IS ASSOCIATED WITH STEROID RESISTANCE IN RESPONSE TO OXIDATIVE STRESS. CRITICAL ISSUES: HISTONE MODIFICATIONS ARE ASSOCIATED WITH DNA DAMAGE/REPAIR AND EPIGENOMIC INSTABILITY AS WELL AS PREMATURE LUNG AGING, WHICH HAVE IMPLICATIONS IN THE PATHOGENESIS OF COPD. HDAC2/SIRTUIN1 (SIRT1)-DEPENDENT CHROMATIN MODIFICATIONS ARE ASSOCIATED WITH DNA DAMAGE-INDUCED INFLAMMATION AND SENESCENCE IN RESPONSE TO CS-MEDIATED OXIDATIVE STRESS. FUTURE DIRECTIONS: UNDERSTANDING CS/OXIDATIVE STRESS-MEDIATED CHROMATIN MODIFICATIONS AND THE CROSS-TALK BETWEEN HISTONE ACETYLATION AND METHYLATION WILL DEMONSTRATE THE INVOLVEMENT OF EPIGENETIC REGULATION OF CHROMATIN REMODELING IN INFLAMMAGING. THIS WILL LEAD TO IDENTIFICATION OF NOVEL EPIGENETIC-BASED THERAPIES AGAINST COPD AND OTHER SMOKING-RELATED LUNG DISEASES. PHARMACOLOGICAL ACTIVATION OF HDAC2/SIRT1 OR REVERSAL OF THEIR OXIDATIVE POST-TRANSLATIONAL MODIFICATIONS MAY OFFER THERAPIES FOR TREATMENT OF COPD AND CS-RELATED DISEASES BASED ON EPIGENETIC HISTONE MODIFICATIONS. 2013 4 1251 36 CURRENT PERSPECTIVES ON ROLE OF CHROMATIN MODIFICATIONS AND DEACETYLASES IN LUNG INFLAMMATION IN COPD. CHROMATIN MODIFICATIONS AND EPIGENETIC REGULATION ARE CRITICAL FOR SUSTAINED AND ABNORMAL INFLAMMATORY RESPONSE SEEN IN LUNGS OF PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) BECAUSE THE ACTIVITIES OF ENZYMES THAT REGULATE THESE EPIGENETIC MODIFICATIONS ARE ALTERED IN RESPONSE TO CIGARETTE SMOKE. CIGARETTE SMOKE INDUCES CHROMATIN MODIFICATIONS AND EPIGENETIC CHANGES BY CAUSING POST-TRANSLATIONAL MODIFICATIONS OF HISTONE ACETYLTRANSFERASES, AND HISTONE/NON-HISTONE DEACETYLASES (HDACS), SUCH AS HDAC2 AND SIRTUIN 1 (SIRT1), WHICH LEADS TO CHROMATIN REMODELING. IN THIS REVIEW, WE DISCUSSED THE CURRENT KNOWLEDGE ON CIGARETTE SMOKE/OXIDANTS-INDUCED POST-TRANSLATIONAL MODIFICATIONS OF DEACETYLASES (HDAC2 AND SIRT1), DISRUPTION OF HDAC2/SIRT1-RELA/P65 COREPRESSOR COMPLEX ASSOCIATED WITH ACETYLATION OF RELA/P65, AND CHROMATIN MODIFICATIONS (HISTONE H3 PHOSPHO-ACETYLATION) LEADING TO SUSTAINED PRO-INFLAMMATORY GENE TRANSCRIPTION. KNOWLEDGE ON MOLECULAR MECHANISMS OF EPIGENETIC CHANGES IN ABNORMAL LUNG INFLAMMATION WILL HELP IN UNDERSTANDING THE PATHOPHYSIOLOGY OF COPD WHICH MAY LEAD TO THE DEVELOPMENT OF NOVEL EPIGENETIC THERAPIES IN THE NEAR FUTURE. 2009 5 6839 28 [LUNG CANCER AND ITS EPIGENETICS ASSOCIATION WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE]. LUNG CANCER AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) ARE THE LEADING CAUSES OF MORBIDITY AND MORTALITY WORLDWIDE. DEVELOPMENT OF LUNG CANCER INVOLVES BOTH GENETIC AND ENVIRONMENT FACTORS. IN ADDITION TO GENETIC ALTERATIONS, EPIGENETIC MECHANISM IS CLOSELY INVOLVED IN PATHOGENESIS OF LUNG CANCER. CHARACTERIZED BY AN ABNORMAL PERSISTENT INFLAMMATORY RESPONSE TO NOXIOUS ENVIRONMENTAL STIMULATION, COPD HAS SHOWN TO INCREASE THE SUSCEPTIBILITY FOR LUNG TUMORIGENESIS IN PREVIOUS RESEARCH. CURRENT RESEARCH ON EPIGENETICS OF LUNG CANCER AND COPD HAS FOCUSED ON ABERRANT DNA METHYLATION, HISTONE ACETYLATION AND NON-CODING RNAS REGULATION. THE ABERRANT DNA METHYLATION ASSOCIATED WITH LUNG CANCER AND COPD HAS INCLUDED OVEREXPRESSION OF DNA METHYLTRANSFERASE, GLOBAL DNA HYPOMETHYLATION AND DNA HYPERMETHYLATION IN PROMOTER REGIONS, WHILE HISTONE ACETYLATION AND HISTONE METHYLATION ARE THE MAJOR CHANGES FOR HISTONE MODIFICATION, IN WHICH HISTONE ACETYLTRANSFERASES, HISTONE DEACETYLASES, HISTONE METHYLTRANSFERASES AND HISTONE DEMETHYLASES PLAY THE MOST IMPORTANT ROLES. RNA INTERFERENCE AND MICRORNAS ARE BOTH HOT TOPICS OF RESEARCH ON NON-CODING RNAS REGULATION. UNDERSTANDING OF CONCURRENT EPIGENETIC ALTERATIONS IN THE PATHOGENESIS OF LUNG CANCER AND COPD MAY FACILITATE IDENTIFICATION OF SPECIFIC THERAPEUTIC TARGETS AND DEVELOPMENT OF EFFECTIVE TREATMENT. 2013 6 2493 37 EPIGENETICS AND CHROMATIN REMODELING PLAY A ROLE IN LUNG DISEASE. EPIGENETICS IS DEFINED AS HERITABLE CHANGES THAT AFFECT GENE EXPRESSION WITHOUT ALTERING THE DNA SEQUENCE. EPIGENETIC REGULATION OF GENE EXPRESSION IS FACILITATED THROUGH DIFFERENT MECHANISMS SUCH AS DNA METHYLATION, HISTONE MODIFICATIONS AND RNA-ASSOCIATED SILENCING BY SMALL NON-CODING RNAS. ALL THESE MECHANISMS ARE CRUCIAL FOR NORMAL DEVELOPMENT, DIFFERENTIATION AND TISSUE-SPECIFIC GENE EXPRESSION. THESE THREE SYSTEMS INTERACT AND STABILIZE ONE ANOTHER AND CAN INITIATE AND SUSTAIN EPIGENETIC SILENCING, THUS DETERMINING HERITABLE CHANGES IN GENE EXPRESSION. HISTONE ACETYLATION REGULATES DIVERSE CELLULAR FUNCTIONS INCLUDING INFLAMMATORY GENE EXPRESSION, DNA REPAIR AND CELL PROLIFERATION. TRANSCRIPTIONAL COACTIVATORS POSSESS INTRINSIC HISTONE ACETYLTRANSFERASE ACTIVITY AND THIS ACTIVITY DRIVES INFLAMMATORY GENE EXPRESSION. ELEVEN CLASSICAL HISTONE DEACETYLASES (HDACS) ACT TO REGULATE THE EXPRESSION OF DISTINCT SUBSETS OF INFLAMMATORY/IMMUNE GENES. THUS, LOSS OF HDAC ACTIVITY OR THE PRESENCE OF HDAC INHIBITORS CAN FURTHER ENHANCE INFLAMMATORY GENE EXPRESSION BY PRODUCING A GENE-SPECIFIC CHANGE IN HAT ACTIVITY. FOR EXAMPLE, HDAC2 EXPRESSION AND ACTIVITY ARE REDUCED IN LUNG MACROPHAGES, BIOPSY SPECIMENS, AND BLOOD CELLS FROM PATIENTS WITH SEVERE ASTHMA AND SMOKING ASTHMATICS, AS WELL AS IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). THIS MAY ACCOUNT, AT LEAST IN PART, FOR THE ENHANCED INFLAMMATION AND REDUCED STEROID RESPONSIVENESS SEEN IN THESE PATIENTS. OTHER PROTEINS, PARTICULARLY TRANSCRIPTION FACTORS, ARE ALSO ACETYLATED AND ARE TARGETS FOR DEACETYLATION BY HDACS AND SIRTUINS, A RELATED FAMILY OF 7 PREDOMINANTLY PROTEIN DEACETYLASES. THUS THE ACETYLATION/DEACETYLATION STATUS OF NF-KAPPAB AND THE GLUCOCORTICOID RECEPTOR CAN ALSO AFFECT THE OVERALL EXPRESSION PATTERN OF INFLAMMATORY GENES AND REGULATE THE INFLAMMATORY RESPONSE. UNDERSTANDING AND TARGETING SPECIFIC ENZYMES INVOLVED IN THIS PROCESS MIGHT LEAD TO NEW THERAPEUTIC AGENTS, PARTICULARLY IN SITUATIONS IN WHICH CURRENT ANTI-INFLAMMATORY THERAPIES ARE SUBOPTIMAL. 2011 7 2161 33 EPIGENETIC MECHANISMS IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE. EPIGENETIC MODIFICATION MAY AFFECT THE EXPRESSION OF MULTIPLE INFLAMMATORY GENES IN LUNGS OF PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). MAJOR EPIGENETIC EVENTS INCLUDE DNA METHYLATION AND VARIOUS POST-TRANSLATIONAL MODIFICATIONS OF HISTONES, SUCH AS HISTONE METHYLATION, ACETYLATION, PHOSPHORYLATION, UBIQUITINATION, AND SUMOYLATION. ENZYMES WHICH REGULATE THESE EPIGENETIC MODIFICATIONS CAN BE ACTIVATED BY SMOKING. BOTH ENVIRONMENTAL AND GENETIC FACTORS PLAY SIGNIFICANT EFFECT IN DEVELOPMENT OF COPD WHICH HAVE BEEN REPORTED BY MOST REFERENCES; HOWEVER, LITTLE IS KNOWN ABOUT THE EPIGENETIC PATHWAYS INVOLVED IN THE DISEASE. UNDERSTANDING THE EPIGENETIC MECHANISMS CAN HELP US CLARIFY THE PATHOGENESIS OF COPD AND IDENTIFY NOVEL TARGETS FOR DEVELOPING NEW THERAPIES FOR PATIENTS WITH COPD. 2015 8 5418 42 REGULATION OF DNA METHYLATION SIGNATURES ON NF-KAPPAB AND STAT3 PATHWAY GENES AND TET ACTIVITY IN CIGARETTE SMOKE EXTRACT-CHALLENGED CELLS/COPD EXACERBATION MODEL IN VITRO. BACKGROUND: CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IS A GLOBAL HEALTH PROBLEM. CURRENTLY, THERE IS A LACK OF KNOWLEDGE ABOUT THE PATHOBIOLOGY OF THIS DISEASE AND AVAILABLE THERAPIES ARE INEFFECTIVE. CIGARETTE SMOKING IS THE LEADING CAUSE OF COPD; HOWEVER, NOT ALL SMOKERS DEVELOP COPD. EXACERBATIONS OF COPD CAUSED BY MICROBES ARE COMMON AND DETRIMENTAL. APPROXIMATELY 20-50% OF PATIENT EXACERBATIONS ARE CAUSED BY BACTERIAL COLONIZATION IN THE LOWER AIRWAYS. IT IS GENERALLY ACCEPTED THAT EPIGENETIC MECHANISMS, ESPECIALLY DNA METHYLATION, PLAY AN IMPORTANT ROLE DURING PROGRESSION OF COPD. THUS, WE HYPOTHESIZED THAT DNA METHYLATION PATTERNS VARY SIGNIFICANTLY FOLLOWING SMOKE EXPOSURE AND DURING EXACERBATIONS CAUSED BY BACTERIAL INFECTIONS. TO TEST OUR HYPOTHESIS, WE USED AN IN VITRO STUDY MODEL THAT MIMICS COPD EXACERBATIONS AND PERFORMED EXTENSIVE STUDIES TO UNDERSTAND THE ROLE OF CPG PROMOTER METHYLATION OF NF-KAPPAB AND STAT3-MEDIATED PATHWAY GENES. BOTH NF-KAPPAB AND STAT3 TRANSCRIPTION FACTORS PLAY CRITICAL ROLES IN ORCHESTRATING INFLAMMATORY RESPONSES DURING CIGARETTE SMOKE EXPOSURE. IN BRIEF, HUMAN LUNG ADENOCARCINOMA CELLS WITH TYPE II ALVEOLAR EPITHELIUM CHARACTERISTICS (A549) WERE CHALLENGED WITH CIGARETTE SMOKE EXTRACT (CSE) OR DMSO (CONTROL) FOLLOWED BY A 3-H CHALLENGE WITH BACTERIAL LIPOPOLYSACCHARIDE (LPS; FROM PSEUDOMONAS AERUGINOSA) PRIOR TO THE TERMINATION OF CSE EXPOSURE (COPD EXACERBATION GROUP). THE PRODUCTION OF CYTOKINES/CHEMOKINES, REGULATION OF TRANSCRIPTION FACTORS, AND DNA METHYLATION OF SPECIFIC GENES WERE THEN ASSESSED. WE ALSO STUDIED CHANGES IN THE EXPRESSION AND ACTIVITY OF TEN-ELEVEN TRANSLOCASES (TETS), THE ENZYMES RESPONSIBLE FOR DNA DEMETHYLATION, AND ASSESSED THEIR ROLE IN REGULATING DNA METHYLATION IN THE CSE-CHALLENGED GROUP. RESULTS: THERE WAS A SIGNIFICANT INCREASE IN THE RELEASE OF CYTOKINES/CHEMOKINES (IL-8, MCP-1, IL-6 AND CCL5) IN THE COPD EXACERBATION GROUP AS COMPARED TO THE CONTROL GROUP. HYPOMETHYLATION OF NF-KAPPAB-MEDIATED PATHWAY GENES CORRELATED WITH THEIR INDUCTION IN OUR COPD EXACERBATION STUDY MODEL. FURTHER, WE OBSERVED AN IMPORTANT ROLE OF TET1/2 IN REGULATING THE DNA METHYLATION OF NF-KAPPAB, STAT3, IKK, AND NIK GENES AND CYTOKINE/CHEMOKINE PRODUCTION BY A549 CELLS DURING CSE CHALLENGE. CONCLUSIONS: STUDIES TO FURTHER DEFINE THE ROLE OF TETS IN CSE-MEDIATED EPIGENETIC REGULATION MAY LEAD TO THE DEVELOPMENT OF BETTER AND MORE EFFECTIVE THERAPEUTIC INTERVENTION STRATEGIES FOR COPD. 2020 9 5560 37 ROLE OF HISTONE DEACETYLASE 2 IN EPIGENETICS AND CELLULAR SENESCENCE: IMPLICATIONS IN LUNG INFLAMMAGING AND COPD. HISTONE DEACETYLASE 2 (HDAC2) IS A CLASS I HISTONE DEACETYLASE THAT REGULATES VARIOUS CELLULAR PROCESSES, SUCH AS CELL CYCLE, SENESCENCE, PROLIFERATION, DIFFERENTIATION, DEVELOPMENT, APOPTOSIS, AND GLUCOCORTICOID FUNCTION IN INHIBITING INFLAMMATORY RESPONSE. HDAC2 HAS BEEN SHOWN TO PROTECT AGAINST DNA DAMAGE RESPONSE AND CELLULAR SENESCENCE/PREMATURE AGING VIA AN EPIGENETIC MECHANISM IN RESPONSE TO OXIDATIVE STRESS. THESE PHENOMENA ARE OBSERVED IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). HDAC2 IS POSTTRANSLATIONALLY MODIFIED BY OXIDATIVE/CARBONYL STRESS IMPOSED BY CIGARETTE SMOKE AND OXIDANTS, LEADING TO ITS REDUCTION VIA AN UBIQUITINATION-PROTEASOME DEPENDENT DEGRADATION IN LUNGS OF PATIENTS WITH COPD. IN THIS PERSPECTIVE, WE HAVE DISCUSSED THE ROLE OF HDAC2 POSTTRANSLATIONAL MODIFICATIONS AND ITS ROLE IN REGULATION OF INFLAMMATION, HISTONE/DNA EPIGENETIC MODIFICATIONS, DNA DAMAGE RESPONSE, AND CELLULAR SENESCENCE, PARTICULARLY IN INFLAMMAGING, AND DURING THE DEVELOPMENT OF COPD. WE HAVE ALSO DISCUSSED THE POTENTIAL DIRECTIONS FOR FUTURE TRANSLATIONAL RESEARCH AVENUES IN MODULATING LUNG INFLAMMAGING AND CELLULAR SENESCENCE BASED ON EPIGENETIC CHROMATIN MODIFICATIONS IN DISEASES ASSOCIATED WITH INCREASED OXIDATIVE STRESS. 2012 10 3193 40 HDAC INHIBITION REGULATES OXIDATIVE STRESS IN CD4(+)THELPER CELLS OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE AND NON-SMALL CELL LUNG CANCER PATIENTS VIA MITOCHONDRIAL TRANSCRIPTION FACTOR A (MTTFA) MODULATING NF-KAPPAB/HIF1ALPHA AXIS. HISTONE DEACETYLASES (HDACS) PLAY A CRUCIAL ROLE IN THE EPIGENETIC REGULATION OF GENE EXPRESSION BY REMODELLING CHROMATIN. ISOENZYMES OF THE HDAC FAMILY EXHIBIT ABERRANT REGULATION IN A WIDE VARIETY OF CANCERS AS WELL AS SEVERAL INFLAMMATORY LUNG DISORDERS LIKE CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). INHIBITION OF HDACS IS A POTENTIAL THERAPEUTIC STRATEGY THAT COULD BE USED TO REVERSE EPIGENETIC MODIFICATION. TRICHOSTATIN A (TSA), A POWERFUL HISTONE DEACETYLASE (HDAC) INHIBITOR, HAS ANTI-CANCER EFFECTS IN NUMEROUS CANCER TYPES. HOWEVER, IT IS NOT YET APPARENT HOW HDAC INHIBITORS AFFECT HUMAN NON-SMALL CELL LUNG CANCER CELLS (NSCLC) AND COPD. THIS STUDY AIMS TO INVESTIGATE TSA'S ROLE IN RESTORING MITOCHONDRIAL DYSFUNCTION AND ITS EFFECT ON HYPOXIA AND INFLAMMATION IN CD4(+)T CELLS OBTAINED FROM PATIENTS WITH COPD AND LUNG CANCER. AS A RESULT OF TREATMENT WITH TSA, THERE IS A REDUCTION IN THE EXPRESSION OF INFLAMMATORY CYTOKINES AND A DECREASED ENRICHMENT OF TRANSCRIPTIONAL FACTORS ASSOCIATED WITH INFLAMMATION AT VEGFA GENE LOCI. WE HAVE SEEN A SUBSTANTIAL DECREASE IN THE EXPRESSION OF NF-KAPPAB AND HIF1ALPHA, WHICH ARE THE CRITICAL MEDIATORS OF INFLAMMATION AND HYPOXIA, RESPECTIVELY. FOLLOWING TSA TREATMENT, MTTFA EXPRESSION WAS INCREASED, FACILITATING PATIENTS WITH COPD AND NSCLC IN THE RECOVERY OF THEIR DYSFUNCTIONAL MITOCHONDRIA. FURTHERMORE, WE HAVE DISCOVERED THAT TSA TREATMENT IN PATIENTS WITH COPD AND NSCLC MAY LEAD TO IMMUNOPROTECTIVE NESS BY INDUCING TH1NESS. OUR FINDING GIVES A NEW INSIGHT INTO THE EXISTING BODY OF KNOWLEDGE REGARDING TSA-BASED THERAPEUTIC METHODS AND HIGHLIGHTS THE NECESSITY OF EPIGENETIC THERAPY FOR THESE DEVASTATING LUNG DISORDERS. 2023 11 5946 35 TARGETING THE EPIGENOME IN THE TREATMENT OF ASTHMA AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE. EPIGENETIC MODIFICATION OF GENE EXPRESSION BY METHYLATION OF DNA AND VARIOUS POST-TRANSLATIONAL MODIFICATIONS OF HISTONES MAY AFFECT THE EXPRESSION OF MULTIPLE INFLAMMATORY GENES. ACETYLATION OF HISTONES BY HISTONE ACETYLTRANSFERASES ACTIVATES INFLAMMATORY GENES, WHEREAS HISTONE DEACETYLATION RESULTS IN INFLAMMATORY GENE REPRESSION. CORTICOSTEROIDS EXERT THEIR ANTIINFLAMMATORY EFFECTS PARTLY BY INDUCING ACETYLATION OF ANTIINFLAMMATORY GENES, BUT MAINLY BY RECRUITING HISTONE DEACETYLASE-2 (HDAC2) TO ACTIVATED INFLAMMATORY GENES. HDAC2 DEACETYLATES ACETYLATED GLUCOCORTICOID RECEPTORS SO THAT THEY CAN SUPPRESS ACTIVATED INFLAMMATORY GENES IN ASTHMA. IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD), THERE IS RESISTANCE TO THE ANTIINFLAMMATORY ACTIONS OF CORTICOSTEROIDS, WHICH IS EXPLAINED BY REDUCED ACTIVITY AND EXPRESSION OF HDAC2. THIS CAN BE REVERSED BY A PLASMID VECTOR, WHICH RESTORES HDAC2 LEVELS, BUT MAY ALSO BE ACHIEVED BY LOW CONCENTRATIONS OF THEOPHYLLINE. OXIDATIVE STRESS CAUSES CORTICOSTEROID RESISTANCE BY REDUCING HDAC2 ACTIVITY AND EXPRESSION BY ACTIVATION OF PHOSPHOINOSITIDE-3-KINASE-DELTA, RESULTING IN HDAC2 PHOSPHORYLATION VIA A CASCADE OF KINASES. THEOPHYLLINE REVERSES CORTICOSTEROID RESISTANCE BY DIRECTLY INHIBITING OXIDANT-ACTIVATED PI3KDELTA AND IS MIMICKED BY PI3KDELTA KNOCKOUT OR BY SELECTIVE INHIBITORS. OTHER TREATMENTS MAY ALSO INTERACT IN THIS PATHWAY, MAKING IT POSSIBLE TO REVERSE CORTICOSTEROID RESISTANCE IN PATIENTS WITH COPD, AS WELL AS IN SMOKERS WITH ASTHMA AND SOME PATIENTS WITH SEVERE ASTHMA IN WHOM SIMILAR MECHANISMS OPERATE. OTHER HISTONE MODIFICATIONS, INCLUDING METHYLATION, TYROSINE NITRATION, AND UBIQUITINATION MAY ALSO AFFECT HISTONE FUNCTION AND INFLAMMATORY GENE EXPRESSION, AND BETTER UNDERSTANDING OF THESE EPIGENETIC PATHWAYS COULD LED TO NOVEL ANTIINFLAMMATORY THERAPIES, PARTICULARLY IN CORTICOSTEROID-RESISTANT INFLAMMATION. 2009 12 172 34 ABSENCE OF HDAC3 BY MATRIX STIFFNESS PROMOTES CHROMATIN REMODELING AND FIBROBLAST ACTIVATION IN IDIOPATHIC PULMONARY FIBROSIS. IDIOPATHIC PULMONARY FIBROSIS (IPF) IS A CHRONIC AND FATAL DISEASE CHARACTERIZED BY PROGRESSIVE AND IRREVERSIBLE LUNG SCARRING ASSOCIATED WITH PERSISTENT ACTIVATION OF FIBROBLASTS. EPIGENETICS COULD INTEGRATE DIVERSE MICROENVIRONMENTAL SIGNALS, SUCH AS STIFFNESS, TO DIRECT PERSISTENT FIBROBLAST ACTIVATION. HISTONE MODIFICATIONS BY DEACETYLASES (HDAC) MAY PLAY AN ESSENTIAL ROLE IN THE GENE EXPRESSION CHANGES INVOLVED IN THE PATHOLOGICAL REMODELING OF THE LUNG. PARTICULARLY, HDAC3 IS CRUCIAL FOR MAINTAINING CHROMATIN AND REGULATING GENE EXPRESSION, BUT LITTLE IS KNOWN ABOUT ITS ROLE IN IPF. IN THE STUDY, CONTROL AND IPF-DERIVED FIBROBLASTS WERE USED TO DETERMINE THE INFLUENCE OF HDAC3 ON CHROMATIN REMODELING AND GENE EXPRESSION ASSOCIATED WITH IPF SIGNATURE. ADDITIONALLY, THE CELLS WERE GROWN ON HYDROGELS TO MIMIC THE STIFFNESS OF A FIBROTIC LUNG. OUR RESULTS SHOWED A DECREASED HDAC3 IN THE NUCLEUS OF IPF FIBROBLASTS, WHICH CORRELATES WITH CHANGES IN NUCLEUS SIZE AND HETEROCHROMATIN LOSS. THE INHIBITION OF HDAC3 WITH A PHARMACOLOGICAL INHIBITOR CAUSES HYPERACETYLATION OF H3K9 AND PROVOKES AN INCREASED EXPRESSION OF COL1A1, ACTA2, AND P21. COMPARABLE RESULTS WERE FOUND IN HYDROGELS, WHERE MATRIX STIFFNESS PROMOTES THE LOSS OF NUCLEAR HDAC3 AND INCREASES THE PROFIBROTIC SIGNATURE. FINALLY, LATRUNCULIN B WAS USED TO CONFIRM THAT CHANGES BY STIFFNESS DEPEND ON THE MECHANOTRANSDUCTION SIGNALS. TOGETHER, THESE RESULTS SUGGEST THAT HDAC3 COULD BE A LINK BETWEEN EPIGENETIC MECHANISMS AND THE FIBROTIC MICROENVIRONMENT. 2023 13 3360 35 HISTONE H4K20 TRIMETHYLATION IS DECREASED IN MURINE MODELS OF HEART DISEASE. HEART DISEASE IS THE LEADING CAUSE OF DEATH IN THE DEVELOPED WORLD, AND ITS COMORBIDITIES SUCH AS HYPERTENSION, DIABETES, AND HEART FAILURE ARE ACCOMPANIED BY MAJOR TRANSCRIPTOMIC CHANGES IN THE HEART. DURING CARDIAC DYSFUNCTION, WHICH LEADS TO HEART FAILURE, THERE ARE GLOBAL EPIGENETIC ALTERATIONS TO CHROMATIN THAT OCCUR CONCOMITANTLY WITH MORPHOLOGICAL CHANGES IN THE HEART IN RESPONSE TO ACUTE AND CHRONIC STRESS. THESE EPIGENETIC ALTERATIONS INCLUDE THE REVERSIBLE METHYLATION OF LYSINE RESIDUES ON HISTONE PROTEINS. LYSINE METHYLATIONS ON HISTONES H3K4 AND H3K9 WERE AMONG THE FIRST METHYLATED LYSINE RESIDUES IDENTIFIED AND HAVE BEEN LINKED TO GENE ACTIVATION AND SILENCING, RESPECTIVELY. HOWEVER, MUCH LESS IS KNOWN REGARDING OTHER METHYLATED HISTONE RESIDUES, INCLUDING HISTONE H4K20. TRIMETHYLATION OF HISTONE H4K20 HAS BEEN SHOWN TO REPRESS GENE EXPRESSION; HOWEVER, THIS MODIFICATION HAS NEVER BEEN EXAMINED IN THE HEART. HERE, WE UTILIZED IMMUNOBLOTTING AND MASS SPECTROMETRY TO QUANTIFY HISTONE H4K20 TRIMETHYLATION IN THREE MODELS OF CARDIAC DYSFUNCTION. OUR RESULTS SHOW THAT LYSINE METHYLATION AT THIS SITE IS DIFFERENTIALLY REGULATED IN THE CARDIOMYOCYTE, LEADING TO INCREASED H4K20 TRIMETHYLATION DURING ACUTE HYPERTROPHIC STRESS IN CELL MODELS AND DECREASED H4K20 TRIMETHYLATION DURING SUSTAINED ISCHEMIC INJURY AND CARDIAC DYSFUNCTION IN ANIMAL MODELS. IN ADDITION, WE EXAMINED PUBLICLY AVAILABLE DATA SETS TO ANALYZE ENZYMES THAT REGULATE H4K20 METHYLATION AND IDENTIFIED TWO DEMETHYLASES (KDM7B AND KDM7C) AND TWO METHYLTRANSFERASES (KMT5A AND SMYD5) THAT WERE ALL DIFFERENTIALLY EXPRESSED IN HEART FAILURE PATIENTS. THIS IS THE FIRST STUDY TO EXAMINE HISTONE H4K20 TRIMETHYLATION IN THE HEART AND TO DETERMINE HOW THIS POST-TRANSLATIONAL MODIFICATION IS DIFFERENTIALLY REGULATED IN MULTIPLE MODELS OF CARDIAC DISEASE. 2022 14 2212 34 EPIGENETIC MODIFICATIONS AND THERAPY IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD): AN UPDATE REVIEW. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) THAT IS ONE OF THE MOST PREVALENT CHRONIC ADULT DISEASES AND THE THIRD LEADING CAUSE OF FATALITY UNTIL 2020. ELASTASE/ANTI-ELASTASE HYPOTHESIS, CHRONIC INFLAMMATION, APOPTOSIS, OXIDANT-ANTIOXIDANT BALANCE AND INFECTIVE REPAIR CAUSE PATHOGENESIS OF COPD ARE AMONG THE FACTORS AT PLAY. EPIGENETIC CHANGES ARE POST-TRANSLATIONAL MODIFICATIONS IN HISTONE PROTEINS AND DNA SUCH AS METHYLATION AND ACETYLATION AS WELL AS DYSREGULATION OF MIRNAS EXPRESSION. IN THIS UPDATE REVIEW, WE HAVE EXAMINED RECENT STUDIES ON THE UPREGULATION OR DOWNREGULATION OF METHYLATION IN DIFFERENT GENES ASSOCIATED WITH COPD. DYSREGULATION OF HDAC ACTIVITY WHICH IS CAUSED BY SOME FACTORS AND MIRNAS PLAYS A KEY ROLE IN THE SUPPRESSION AND REDUCTION OF COPD DEVELOPMENT. ALSO, SOME THERAPEUTIC APPROACHES ARE PROPOSED AGAINST COPD BY TARGETING HDAC2 AND MIRNAS, WHICH HAVE THERAPEUTIC EFFECTS. 2020 15 2055 27 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 16 2228 33 EPIGENETIC MODIFICATIONS OF HISTONES IN PERIODONTAL DISEASE. PERIODONTITIS IS A CHRONIC INFECTIOUS DISEASE DRIVEN BY DYSBIOSIS, AN IMBALANCE BETWEEN COMMENSAL BACTERIA AND THE HOST ORGANISM. PERIODONTITIS IS A LEADING CAUSE OF TOOTH LOSS IN ADULTS AND OCCURS IN ABOUT 50% OF THE US POPULATION. IN ADDITION TO THE CLINICAL CHALLENGES ASSOCIATED WITH TREATING PERIODONTITIS, THE PROGRESSION AND CHRONIC NATURE OF THIS DISEASE SERIOUSLY AFFECT HUMAN HEALTH. EMERGING EVIDENCE SUGGESTS THAT PERIODONTITIS IS ASSOCIATED WITH MECHANISMS BEYOND BACTERIA-INDUCED PROTEIN AND TISSUE DEGRADATION. HERE, WE HYPOTHESIZE THAT BACTERIA ARE ABLE TO INDUCE EPIGENETIC MODIFICATIONS IN ORAL EPITHELIAL CELLS MEDIATED BY HISTONE MODIFICATIONS. IN THIS STUDY, WE FOUND THAT DYSBIOSIS IN VIVO LED TO EPIGENETIC MODIFICATIONS, INCLUDING ACETYLATION OF HISTONES AND DOWNREGULATION OF DNA METHYLTRANSFERASE 1. IN ADDITION, IN VITRO EXPOSURE OF ORAL EPITHELIAL CELLS TO LIPOPOLYSACCHARIDES RESULTED IN HISTONE MODIFICATIONS, ACTIVATION OF TRANSCRIPTIONAL COACTIVATORS, SUCH AS P300/CBP, AND ACCUMULATION OF NUCLEAR FACTOR-KAPPAB (NF-KAPPAB). GIVEN THAT ORAL EPITHELIAL CELLS ARE THE FIRST LINE OF DEFENSE FOR THE PERIODONTIUM AGAINST BACTERIA, WE ALSO EVALUATED WHETHER ACTIVATION OF PATHOGEN RECOGNITION RECEPTORS INDUCED HISTONE MODIFICATIONS. WE FOUND THAT ACTIVATION OF THE TOLL-LIKE RECEPTORS 1, 2, AND 4 AND THE NUCLEOTIDE-BINDING OLIGOMERIZATION DOMAIN PROTEIN 1 INDUCED HISTONE ACETYLATION IN ORAL EPITHELIAL CELLS. OUR FINDINGS CORROBORATE THE EMERGING CONCEPT THAT EPIGENETIC MODIFICATIONS PLAY A ROLE IN THE DEVELOPMENT OF PERIODONTITIS. 2016 17 1326 22 DEPLETION OF NUCLEAR HISTONE H2A VARIANTS IS ASSOCIATED WITH CHRONIC DNA DAMAGE SIGNALING UPON DRUG-EVOKED SENESCENCE OF HUMAN SOMATIC CELLS. CELLULAR SENESCENCE IS ASSOCIATED WITH GLOBAL CHROMATIN CHANGES, ALTERED GENE EXPRESSION, AND ACTIVATION OF CHRONIC DNA DAMAGE SIGNALING. THESE EVENTS ULTIMATELY LEAD TO MORPHOLOGICAL AND PHYSIOLOGICAL TRANSFORMATIONS IN PRIMARY CELLS. IN THIS STUDY, WE SHOW THAT CHRONIC DNA DAMAGE SIGNALS CAUSED BY GENOTOXIC STRESS IMPACT THE EXPRESSION OF HISTONES H2A FAMILY MEMBERS AND LEAD TO THEIR DEPLETION IN THE NUCLEI OF SENESCENT HUMAN FIBROBLASTS. OUR DATA REINFORCE THE HYPOTHESIS THAT PROGRESSIVE CHROMATIN DESTABILIZATION MAY LEAD TO THE LOSS OF EPIGENETIC INFORMATION AND IMPAIRED CELLULAR FUNCTION ASSOCIATED WITH CHRONIC DNA DAMAGE UPON DRUG-EVOKED SENESCENCE. WE PROPOSE THAT CHANGES IN THE HISTONE BIOSYNTHESIS AND CHROMATIN ASSEMBLY MAY DIRECTLY CONTRIBUTE TO CELLULAR AGING. IN ADDITION, WE ALSO OUTLINE THE METHOD THAT ALLOWS FOR QUANTITATIVE AND UNBIASED MEASUREMENT OF THESE CHANGES. 2012 18 4302 41 MICRORNA-223 CONTROLS THE EXPRESSION OF HISTONE DEACETYLASE 2: A NOVEL AXIS IN COPD. REDUCED ACTIVITY OF HISTONE DEACETYLASE 2 (HDAC2) HAS BEEN DESCRIBED IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD), BUT THE MECHANISMS RESULTING IN DECREASED EXPRESSION OF THIS IMPORTANT EPIGENETIC MODIFIER REMAIN UNKNOWN. HERE, WE EMPLOYED SEVERAL IN VITRO EXPERIMENTS TO ADDRESS THE ROLE OF MICRORNAS (MIRNAS) ON THE REGULATION OF HDAC2 IN ENDOTHELIAL CELLS. MANIPULATION OF MIRNA LEVELS IN HUMAN PULMONARY ARTERY ENDOTHELIAL CELLS (HPAEC) WAS ACHIEVED BY USING ELECTROPORATION WITH ANTI-MIRNAS AND MIRNA MIMICS. TARGET PREDICTION SOFTWARE IDENTIFIED MIR-223 AS A POTENTIAL REPRESSOR OF HDAC2. IN SUBSEQUENT STIMULATION EXPERIMENTS USING INFLAMMATORY CYTOKINES KNOWN TO BE INCREASED IN PATIENTS WITH COPD, MIR-223 WAS FOUND TO BE SIGNIFICANTLY INDUCED. FUNCTIONAL ANALYSIS DEMONSTRATED THAT OVEREXPRESSION OF MIR-223 DECREASED HDAC2 EXPRESSION AND ACTIVITY IN HPAEC. CONVERSELY, HDAC2 EXPRESSION AND ACTIVITY WAS PRESERVED IN ANTI-MIR-223-TREATED CELLS. DIRECT MIRNA-TARGET INTERACTION WAS CONFIRMED BY REPORTER GENE ASSAY. IN A NEXT STEP, REDUCED EXPRESSION OF HDAC2 WAS FOUND TO INCREASE THE LEVELS OF THE CHEMOKINE FRACTALKINE (CX3CL1). IN VIVO STUDIES CONFIRMED ELEVATED EXPRESSION LEVELS OF MIR-223 IN MICE EXPOSED TO CIGARETTE SMOKE AND IN EMPHYSEMATOUS LUNG TISSUE FROM LPS-TREATED MICE. MOREOVER, A SIGNIFICANT INVERSE CORRELATION OF MIR-223 AND HDAC2 EXPRESSION WAS FOUND IN TWO INDEPENDENT COHORTS OF COPD PATIENTS. THESE DATA EMPHASIZE THAT MIR-223, THE MOST PREVALENT MIRNA IN COPD, CONTROLS EXPRESSION AND ACTIVITY OF HDAC2 IN PULMONARY CELLS, WHICH, IN TURN, MIGHT ALTER THE EXPRESSION PROFILE OF CHEMOKINES. THIS PATHWAY PROVIDES A NOVEL PATHOGENIC LINK BETWEEN DYSREGULATED MIRNA EXPRESSION AND EPIGENETIC ACTIVITY IN COPD. KEY MESSAGES: HISTONE DEACETYLASE 2 IS DIRECTLY TARGETED BY MIR-223. LEVELS OF MIR-223 ARE INDUCED BY INTERLEUKIN-1BETA AND TUMOR NECROSIS FACTOR-ALPHA. MIR-223 CONTROLS THE EXPRESSION OF FRACTALKINE BY TARGETING HISTONE DEACETYLASE 2. MIR-223 LEVELS ARE INCREASED IN COPD MOUSE MODELS. MIR-223 LEVELS INVERSELY CORRELATE WITH HDAC2 EXPRESSION IN COPD PATIENTS. 2016 19 2926 28 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 20 3322 34 HISTONE ACETYLTRANSFERASE P300 INDUCES DE NOVO SUPER-ENHANCERS TO DRIVE CELLULAR SENESCENCE. ACCUMULATION OF SENESCENT CELLS DURING AGING CONTRIBUTES TO CHRONIC INFLAMMATION AND AGE-RELATED DISEASES. WHILE SENESCENCE IS ASSOCIATED WITH PROFOUND ALTERATIONS OF THE EPIGENOME, A SYSTEMATIC VIEW OF EPIGENETIC FACTORS IN REGULATING SENESCENCE IS LACKING. HERE, WE CURATED A LIBRARY OF SHORT HAIRPIN RNAS FOR TARGETED SILENCING OF ALL KNOWN EPIGENETIC PROTEINS AND PERFORMED A HIGH-THROUGHPUT SCREEN TO IDENTIFY KEY CANDIDATES WHOSE DOWNREGULATION CAN DELAY REPLICATIVE SENESCENCE OF PRIMARY HUMAN CELLS. THIS SCREEN IDENTIFIED MULTIPLE NEW PLAYERS INCLUDING THE HISTONE ACETYLTRANSFERASE P300 THAT WAS FOUND TO BE A PRIMARY DRIVER OF THE SENESCENT PHENOTYPE. P300, BUT NOT THE PARALOGOUS CBP, INDUCES A DYNAMIC HYPER-ACETYLATED CHROMATIN STATE AND PROMOTES THE FORMATION OF ACTIVE ENHANCER ELEMENTS IN THE NON-CODING GENOME, LEADING TO A SENESCENCE-SPECIFIC GENE EXPRESSION PROGRAM. OUR WORK ILLUSTRATES A CAUSAL ROLE OF HISTONE ACETYLTRANSFERASES AND ACETYLATION IN SENESCENCE AND SUGGESTS P300 AS A POTENTIAL THERAPEUTIC TARGET FOR SENESCENCE AND AGE-RELATED DISEASES. 2019