1 4889 134 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 2 1251 50 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 3 1012 49 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 4 5560 51 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 5 6839 38 [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 2161 41 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 7 2212 42 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 8 1245 41 CURRENT CONCEPTS ON THE ROLE OF INFLAMMATION IN COPD AND LUNG CANCER. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) AND LUNG CANCER ARE LEADING CAUSE OF DEATH, AND BOTH ARE ASSOCIATED WITH CIGARETTE SMOKE EXPOSURE. IT HAS BEEN SHOWN THAT 50-70% OF PATIENTS DIAGNOSED WITH LUNG CANCER SUFFER FROM COPD, AND REDUCED LUNG FUNCTION IS AN IMPORTANT EVENT IN LUNG CANCER SUGGESTING AN ASSOCIATION BETWEEN COPD AND LUNG CANCER. HOWEVER, A CAUSAL RELATIONSHIP BETWEEN COPD AND LUNG TUMORIGENESIS IS NOT YET FULLY UNDERSTOOD. RECENT STUDIES HAVE SUGGESTED A CENTRAL ROLE OF CHRONIC INFLAMMATION IN THE PATHOGENESIS OF BOTH THE DISEASES. FOR EXAMPLE, IMMUNE DYSFUNCTION, ABNORMAL ACTIVATION OF NF-KAPPAB, EPITHELIAL-TO-MESENCHYMAL TRANSITION, ALTERED ADHESION SIGNALING PATHWAYS, AND EXTRACELLULAR MATRIX DEGRADATION/ALTERED SIGNALING ARE THE KEY UNDERLYING MECHANISMS IN BOTH COPD AND LUNG CANCER. THESE PARAMETERS ALONG WITH OTHER PROCESSES, SUCH AS CHROMATIN MODIFICATIONS/EPIGENETIC CHANGES, ANGIOGENESIS, AND AUTOPHAGY/APOPTOSIS ARE ALTERED BY CIGARETTE SMOKE, ARE CRUCIAL IN THE DEVELOPMENT OF COPD AND LUNG CANCER. UNDERSTANDING THE CELLULAR AND MOLECULAR MECHANISMS UNDERLYING THESE PROCESSES WILL PROVIDE NOVEL AVENUES FOR HALTING THE CHRONIC INFLAMMATION IN COPD AND DEVISING THERAPEUTIC STRATEGIES AGAINST LUNG CANCER. 2009 9 3193 45 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 10 2493 49 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 11 1244 48 CURRENT CONCEPTS ON OXIDATIVE/CARBONYL STRESS, INFLAMMATION AND EPIGENETICS IN PATHOGENESIS OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IS A GLOBAL HEALTH PROBLEM. THE CURRENT THERAPIES FOR COPD ARE POORLY EFFECTIVE AND THE MAINSTAYS OF PHARMACOTHERAPY ARE BRONCHODILATORS. A BETTER UNDERSTANDING OF THE PATHOBIOLOGY OF COPD IS CRITICAL FOR THE DEVELOPMENT OF NOVEL THERAPIES. IN THE PRESENT REVIEW, WE HAVE DISCUSSED THE ROLES OF OXIDATIVE/ALDEHYDE STRESS, INFLAMMATION/IMMUNITY, AND CHROMATIN REMODELING IN THE PATHOGENESIS OF COPD. AN IMBALANCE OF OXIDANTS/ANTIOXIDANTS CAUSED BY CIGARETTE SMOKE AND OTHER POLLUTANTS/BIOMASS FUELS PLAYS AN IMPORTANT ROLE IN THE PATHOGENESIS OF COPD BY REGULATING REDOX-SENSITIVE TRANSCRIPTION FACTORS (E.G., NF-KAPPAB), AUTOPHAGY AND UNFOLDED PROTEIN RESPONSE LEADING TO CHRONIC LUNG INFLAMMATORY RESPONSE. CIGARETTE SMOKE ALSO ACTIVATES CANONICAL/ALTERNATIVE NF-KAPPAB PATHWAYS AND THEIR UPSTREAM KINASES LEADING TO SUSTAINED INFLAMMATORY RESPONSE IN LUNGS. RECENTLY, EPIGENETIC REGULATION HAS BEEN SHOWN TO BE CRITICAL FOR THE DEVELOPMENT OF COPD BECAUSE THE EXPRESSION/ACTIVITY OF ENZYMES THAT REGULATE THESE EPIGENETIC MODIFICATIONS HAVE BEEN REPORTED TO BE ABNORMAL IN AIRWAYS OF COPD PATIENTS. HENCE, THE SIGNIFICANT ADVANCES MADE IN UNDERSTANDING THE PATHOPHYSIOLOGY OF COPD AS DESCRIBED HEREIN WILL IDENTIFY NOVEL THERAPEUTIC TARGETS FOR INTERVENTION IN COPD. 2011 12 4026 37 LUNG CANCER AND ITS ASSOCIATION WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE: UPDATE ON NEXUS OF EPIGENETICS. PURPOSE OF REVIEW: CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) AND LUNG CANCER ARE THE LEADING CAUSES OF MORBIDITY AND MORTALITY WORLDWIDE. THE CURRENT RESEARCH IS FOCUSED ON IDENTIFYING THE COMMON AND DISPARATE EVENTS INVOLVED IN EPIGENETIC MODIFICATIONS THAT CONCURRENTLY OCCUR DURING THE PATHOGENESIS OF COPD AND LUNG CANCER. THE PURPOSE OF THIS REVIEW IS TO DESCRIBE THE CURRENT KNOWLEDGE AND UNDERSTANDING OF EPIGENETIC MODIFICATIONS IN PATHOGENESIS OF COPD AND LUNG CANCER. RECENT FINDINGS: THIS REVIEW PROVIDES AN UPDATE ON ADVANCES OF HOW EPIGENETIC MODIFICATIONS ARE LINKED TO COPD AND LUNG CANCER, AND THEIR COMMONALITIES AND DISPARITIES. THE KEY EPIGENETIC MODIFICATION ENZYMES (E.G. DNA METHYLTRANSFERASES -- CPG METHYLATION, HISTONE ACETYLASES/DEACETYLASES AND HISTONE METHYLTRANSFERASES/DEMETHYLASES) THAT ARE IDENTIFIED TO PLAY AN IMPORTANT ROLE IN COPD AND LUNG TUMORIGENESIS AND PROGRESSION ARE DESCRIBED IN THIS REVIEW. SUMMARY: DISTINCT DNA METHYLTRANSFERASES AND HISTONE MODIFICATION ENZYMES ARE DIFFERENTIALLY INVOLVED IN PATHOGENESIS OF LUNG CANCER AND COPD, ALTHOUGH SOME OF THE MODIFICATIONS ARE COMMON. UNDERSTANDING THE EPIGENETIC MODIFICATIONS INVOLVED IN PATHOGENESIS OF LUNG CANCER OR COPD WITH RESPECT TO COMMON AND DISPARATE MECHANISMS WILL LEAD TO TARGETING OF EPIGENETIC THERAPIES AGAINST THESE DISORDERS. 2011 13 1326 27 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 14 6100 43 THE EMERGING ROLE OF EPIGENETIC MODIFIERS IN REPAIR OF DNA DAMAGE ASSOCIATED WITH CHRONIC INFLAMMATORY DISEASES. AT SITES OF CHRONIC INFLAMMATION EPITHELIAL CELLS ARE EXPOSED TO HIGH LEVELS OF REACTIVE OXYGEN SPECIES (ROS), WHICH CAN CONTRIBUTE TO THE INITIATION AND DEVELOPMENT OF MANY DIFFERENT HUMAN CANCERS. ABERRANT EPIGENETIC ALTERATIONS THAT CAUSE TRANSCRIPTIONAL SILENCING OF TUMOR SUPPRESSOR GENES ARE ALSO IMPLICATED IN MANY DISEASES ASSOCIATED WITH INFLAMMATION, INCLUDING CANCER. HOWEVER, IT IS NOT CLEAR HOW ALTERED EPIGENETIC GENE SILENCING IS INITIATED DURING CHRONIC INFLAMMATION. THE HIGH LEVEL OF ROS AT SITES OF INFLAMMATION IS KNOWN TO INDUCE OXIDATIVE DNA DAMAGE IN SURROUNDING EPITHELIAL CELLS. FURTHERMORE, DNA DAMAGE IS KNOWN TO TRIGGER SEVERAL RESPONSES, INCLUDING RECRUITMENT OF DNA REPAIR PROTEINS, TRANSCRIPTIONAL REPRESSION, CHROMATIN MODIFICATIONS AND OTHER CELL SIGNALING EVENTS. RECRUITMENT OF EPIGENETIC MODIFIERS TO CHROMATIN IN RESPONSE TO DNA DAMAGE RESULTS IN TRANSIENT COVALENT MODIFICATIONS TO CHROMATIN SUCH AS HISTONE UBIQUITINATION, ACETYLATION AND METHYLATION AND DNA METHYLATION. DNA DAMAGE ALSO ALTERS NON-CODING RNA EXPRESSION. ALL OF THESE ALTERATIONS HAVE THE POTENTIAL TO ALTER GENE EXPRESSION AT SITES OF DAMAGE. TYPICALLY, THESE MODIFICATIONS AND GENE TRANSCRIPTION ARE RESTORED BACK TO NORMAL ONCE THE REPAIR OF THE DNA DAMAGE IS COMPLETED. HOWEVER, CHRONIC INFLAMMATION MAY INDUCE SUSTAINED DNA DAMAGE AND DNA DAMAGE RESPONSES THAT RESULT IN THESE TRANSIENT COVALENT CHROMATIN MODIFICATIONS BECOMING MITOTICALLY STABLE EPIGENETIC ALTERATIONS. UNDERSTANDING HOW EPIGENETIC ALTERATIONS ARE INITIATED DURING CHRONIC INFLAMMATION WILL ALLOW US TO DEVELOP PHARMACEUTICAL STRATEGIES TO PREVENT OR TREAT CHRONIC INFLAMMATION-INDUCED CANCER. THIS REVIEW WILL FOCUS ON TYPES OF DNA DAMAGE AND EPIGENETIC ALTERATIONS ASSOCIATED WITH CHRONIC INFLAMMATORY DISEASES, THE TYPES OF DNA DAMAGE AND TRANSIENT COVALENT CHROMATIN MODIFICATIONS INDUCED BY INFLAMMATION AND OXIDATIVE DNA DAMAGE AND HOW THESE MODIFICATIONS MAY RESULT IN EPIGENETIC ALTERATIONS. 2019 15 2059 39 EPIGENETIC CONTROL OF GENE EXPRESSION IN THE LUNG. EPIGENETICS IS TRADITIONALLY DEFINED AS THE STUDY OF HERITABLE CHANGES IN GENE EXPRESSION CAUSED BY MECHANISMS OTHER THAN CHANGES IN THE UNDERLYING DNA SEQUENCE. THERE ARE THREE MAIN CLASSES OF EPIGENETIC MARKS--DNA METHYLATION, MODIFICATIONS OF HISTONE TAILS, AND NONCODING RNAS--EACH OF WHICH MAY BE INFLUENCED BY THE ENVIRONMENT, DIET, DISEASES, AND AGEING. IMPORTANTLY, EPIGENETIC MARKS HAVE BEEN SHOWN TO INFLUENCE IMMUNE CELL MATURATION AND ARE ASSOCIATED WITH THE RISK OF DEVELOPING VARIOUS FORMS OF CANCER, INCLUDING LUNG CANCER. MOREOVER, THERE IS EMERGING EVIDENCE THAT THESE EPIGENETIC MARKS AFFECT GENE EXPRESSION IN THE LUNG AND ARE ASSOCIATED WITH BENIGN LUNG DISEASES, SUCH AS ASTHMA, CHRONIC OBSTRUCTIVE PULMONARY DISEASE, AND INTERSTITIAL LUNG DISEASE. TECHNOLOGICAL ADVANCES HAVE MADE IT FEASIBLE TO STUDY EPIGENETIC MARKS IN THE LUNG, AND IT IS ANTICIPATED THAT THIS KNOWLEDGE WILL ENHANCE OUR UNDERSTANDING OF THE DYNAMIC BIOLOGY IN THE LUNG AND LEAD TO THE DEVELOPMENT OF NOVEL DIAGNOSTIC AND THERAPEUTIC APPROACHES FOR OUR PATIENTS WITH LUNG DISEASE. 2011 16 6533 41 TRANSCRIPTIONAL REGULATION OF INFLAMMATORY GENES ASSOCIATED WITH SEVERE ASTHMA. THE 10% OF PATIENTS WITH THE MOST SEVERE ASTHMA ARE RESPONSIBLE FOR A LARGE PART OF HEALTHCARE EXPENDITURE AND MORBIDITY. UNDERSTANDING THE PROCESSES INVOLVED IS KEY IF NEW THERAPEUTIC APPROACHES ARE TO BE DEVELOPED. EVIDENCE IS ACCUMULATING THAT CHRONIC DISEASES SUCH AS ASTHMA ARE ASSOCIATED WITH TEMPORAL AND SPATIAL ALTERATIONS IN THE PATTERN OF INFLAMMATORY GENE EXPRESSION WITHIN THE AIRWAYS. EXPRESSION OF THESE GENES CAN BE REGULATED BY TRANSCRIPTIONAL, POSTTRANSCRIPTIONAL, TRANSLATIONAL AND EPIGENETIC MECHANISMS. IT IS WELL ESTABLISHED THAT BINDING OF ACTIVATED TRANSCRIPTION FACTORS TO SPECIFIC INDUCIBLE GENE PROMOTER SITES IS TIGHTLY CONTROLLED BY CHROMATIN STATE AS A RESULT OF HISTONE MODIFICATIONS, PARTICULARLY THE BALANCE BETWEEN HISTONE ACETYLATION AND DEACETYLATION [1]. THE INTERACTION BETWEEN TRANSCRIPTION FACTORS AND THE PROMOTER IS KEY TO THE DIVERSIFICATION OF GENE EXPRESSION IN A TIME DEPENDENT MANNER LEADING TO ALTERED GENE EXPRESSION PROFILES. ALTERATIONS OF THE ACCESSIBILITY OF TRANSCRIPTION FACTORS TO THE DNA CAN HAVE RESIDING EFFECTS UPON GENE TRANSCRIPTION. THIS REVIEW WILL FOCUS ON THE REGULATION OF SEVERAL GROUPS OF KEY GENES WHICH ARE INVOLVED IN CHRONIC AIRWAY INFLAMMATION AND REMODELLING IN ASTHMA DRAWING MAINLY FROM OUR EXPERIENCE OF STUDYING THESE PROCESSES IN AIRWAY SMOOTH MUSCLE CELLS. AN OVERVIEW IS SHOWN IN FIGURE 1. 2011 17 3543 27 IMMUNOLOGY, GENETICS AND MICROBIOTA IN THE COPD PATHOPHYSIOLOGY: POTENTIAL SCOPE FOR PATIENT STRATIFICATION. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IS CHARACTERIZED BY SUSTAINED INFLAMMATION OF THE AIRWAYS, LEADING TO DESTRUCTION OF LUNG TISSUE AND DECLINING PULMONARY FUNCTION. ALTHOUGH SMOKING IS THE MOST OBVIOUS RISK FACTOR FOR COPD, ONLY ABOUT 20% OF SMOKERS DEVELOP COPD AND SMOKING CESSATION DOES NOT REVERSE PROGRESSION OF COPD, INDICATING THAT WHILE SMOKING IS AN IMPORTANT CAUSE OR INITIATING FACTOR, IT IS NOT THE ONLY DRIVER OF ONGOING CHRONIC INFLAMMATION AND DISEASE PROGRESSION IN COPD PATIENTS. WE HYPOTHESIZE THAT SMOKING-INDUCED CHANGES IN LUNG MICROBIOTA, EPITHELIAL INTEGRITY AND EPIGENETIC CONTROL OF GENE EXPRESSION RESULT IN AUTOANTIGEN INDUCTION AND PERTURBED IMMUNE REGULATION IN GENETICALLY VUNERABLE INDIVIDUALS. IN OUR VIEW, COPD PATIENTS MAY BE STRATIFIED ACCORDING TO THEIR IMMUNOLOGICAL AND INFLAMMATORY STATUS RELATED TO SPECIFIC CHANGES IN THE LUNG MICROBIOTA (INNATE AND ADAPTIVE IMMUNITY), PRESENCE OF AUTOANTIGENS (ADAPTIVE IMMUNITY: TH1-B-CELL AXIS) AND EPIGENETIC MODIFICATIONS (INFLAMMATION AND STRUCTURAL CHANGES). 2015 18 5946 50 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 19 2308 37 EPIGENETIC REGULATION OF CHEMOKINE (CC-MOTIF) LIGAND 2 IN INFLAMMATORY DISEASES. APPROPRIATE RESPONSES TO INFLAMMATION ARE CONDUCIVE TO PATHOGEN ELIMINATION AND TISSUE REPAIR, WHILE UNCONTROLLED INFLAMMATORY REACTIONS ARE LIKELY TO RESULT IN THE DAMAGE OF TISSUES. CHEMOKINE (CC-MOTIF) LIGAND 2 (CCL2) IS THE MAIN CHEMOKINE AND ACTIVATOR OF MONOCYTES, MACROPHAGES, AND NEUTROPHILS. CCL2 PLAYED A KEY ROLE IN AMPLIFYING AND ACCELERATING THE INFLAMMATORY CASCADE AND IS CLOSELY RELATED TO CHRONIC NON-CONTROLLABLE INFLAMMATION (CIRRHOSIS, NEUROPATHIC PAIN, INSULIN RESISTANCE, ATHEROSCLEROSIS, DEFORMING ARTHRITIS, ISCHEMIC INJURY, CANCER, ETC.). THE CRUCIAL REGULATORY ROLES OF CCL2 MAY PROVIDE POTENTIAL TARGETS FOR THE TREATMENT OF INFLAMMATORY DISEASES. THEREFORE, WE PRESENTED A REVIEW OF THE REGULATORY MECHANISMS OF CCL2. GENE EXPRESSION IS LARGELY AFFECTED BY THE STATE OF CHROMATIN. DIFFERENT EPIGENETIC MODIFICATIONS, INCLUDING DNA METHYLATION, POST-TRANSLATIONAL MODIFICATION OF HISTONES, HISTONE VARIANTS, ATP-DEPENDENT CHROMATIN REMODELLING, AND NON-CODING RNA, COULD AFFECT THE 'OPEN' OR 'CLOSED' STATE OF DNA, AND THEN SIGNIFICANTLY AFFECT THE EXPRESSION OF TARGET GENES. SINCE MOST EPIGENETIC MODIFICATIONS ARE PROVEN TO BE REVERSIBLE, TARGETING THE EPIGENETIC MECHANISMS OF CCL2 IS EXPECTED TO BE A PROMISING THERAPEUTIC STRATEGY FOR INFLAMMATORY DISEASES. THIS REVIEW FOCUSES ON THE EPIGENETIC REGULATION OF CCL2 IN INFLAMMATORY DISEASES. 2023 20 5418 40 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