1 3204 144 HDAC3 REGULATES GINGIVAL FIBROBLAST INFLAMMATORY RESPONSES IN PERIODONTITIS. HISTONE DEACETYLASES (HDACS) ARE IMPORTANT REGULATORS OF GENE EXPRESSION THAT ARE ABERRANTLY REGULATED IN SEVERAL INFLAMMATORY AND INFECTIOUS DISEASES. HDAC INHIBITORS (HDACI) SUPPRESS INFLAMMATORY ACTIVATION OF VARIOUS CELL TYPES THROUGH EPIGENETIC AND NON-EPIGENETIC MECHANISMS, AND AMELIORATE PATHOLOGY IN A MOUSE MODEL OF PERIODONTITIS. ACTIVATION OF GINGIVAL FIBROBLASTS (GFS) SIGNIFICANTLY CONTRIBUTES TO THE DEVELOPMENT OF PERIODONTITIS AND THE ANAEROBIC BACTERIUM PORPHYROMONAS GINGIVALIS PLAYS A KEY ROLE IN DRIVING CHRONIC INFLAMMATION. HERE, WE ANALYZED THE ROLE OF HDACS IN INFLAMMATORY RESPONSES OF GFS. PAN-HDACI SUBEROYLANILIDE HYDROXAMIC ACID (SAHA) AND/OR ITF2357 (GIVINOSTAT) SIGNIFICANTLY REDUCED TNFALPHA- AND P. GINGIVALIS-INDUCIBLE EXPRESSION AND/OR PRODUCTION OF A CLUSTER OF INFLAMMATORY MEDIATORS IN HEALTHY DONOR GFS (IL1B, CCL2, CCL5, CXCL10, COX2, AND MMP3) WITHOUT AFFECTING CELL VIABILITY. SELECTIVE INHIBITION OF HDAC3/6, BUT NOT SPECIFIC HDAC1, HDAC6, OR HDAC8 INHIBITION, REPRODUCED THE SUPPRESSIVE EFFECTS OF PAN-HDACI ON THE INFLAMMATORY GENE EXPRESSION PROFILE INDUCED BY TNFALPHA AND P. GINGIVALIS, SUGGESTING A CRITICAL ROLE FOR HDAC3 IN GF INFLAMMATORY ACTIVATION. CONSISTENTLY, SILENCING OF HDAC3 EXPRESSION WITH SIRNA LARGELY RECAPITULATED THE EFFECTS OF HDAC3/6I ON MRNA LEVELS OF INFLAMMATORY MEDIATORS IN P. GINGIVALIS-INFECTED GFS. IN CONTRAST, P. GINGIVALIS INTERNALIZATION AND INTRACELLULAR SURVIVAL IN GFS REMAINED UNAFFECTED BY HDACI. ACTIVATION OF MITOGEN-ACTIVATED PROTEIN KINASES AND NFKAPPAB SIGNALING WAS UNAFFECTED BY GLOBAL OR HDAC3/6-SELECTIVE HDACI, AND NEW PROTEIN SYNTHESIS WAS NOT REQUIRED FOR GENE SUPPRESSION BY HDACI. FINALLY, PAN-HDACI AND HDAC3/6I SUPPRESSED P. GINGIVALIS-INDUCED EXPRESSION OF IL1B, CCL2, CCL5, CXCL10, MMP1, AND MMP3 IN GFS FROM PATIENTS WITH PERIODONTITIS. OUR RESULTS IDENTIFY HDAC3 AS AN IMPORTANT REGULATOR OF INFLAMMATORY GENE EXPRESSION IN GFS AND SUGGEST THAT THERAPEUTIC TARGETING OF HDAC ACTIVITY, IN PARTICULAR HDAC3, MAY BE CLINICALLY BENEFICIAL IN SUPPRESSING INFLAMMATION IN PERIODONTAL DISEASE. 2020 2 589 73 BET BROMODOMAIN INHIBITORS SUPPRESS INFLAMMATORY ACTIVATION OF GINGIVAL FIBROBLASTS AND EPITHELIAL CELLS FROM PERIODONTITIS PATIENTS. BET BROMODOMAIN PROTEINS ARE IMPORTANT EPIGENETIC REGULATORS OF GENE EXPRESSION THAT BIND ACETYLATED HISTONE TAILS AND REGULATE THE FORMATION OF ACETYLATION-DEPENDENT CHROMATIN COMPLEXES. BET INHIBITORS SUPPRESS INFLAMMATORY RESPONSES IN MULTIPLE CELL TYPES AND ANIMAL MODELS, AND PROTECT AGAINST BONE LOSS IN EXPERIMENTAL PERIODONTITIS IN MICE. HERE, WE ANALYZED THE ROLE OF BET PROTEINS IN INFLAMMATORY ACTIVATION OF GINGIVAL FIBROBLASTS (GFS) AND GINGIVAL EPITHELIAL CELLS (GECS). WE SHOW THAT THE BET INHIBITORS I-BET151 AND JQ1 SIGNIFICANTLY REDUCED EXPRESSION AND/OR PRODUCTION OF DISTINCT, BUT OVERLAPPING, PROFILES OF CYTOKINE-INDUCIBLE MEDIATORS OF INFLAMMATION AND BONE RESORPTION IN GFS FROM HEALTHY DONORS (IL6, IL8, IL1B, CCL2, CCL5, COX2, AND MMP3) AND THE GEC LINE TIGK (IL6, IL8, IL1B, CXCL10, MMP9) WITHOUT AFFECTING CELL VIABILITY. ACTIVATION OF MITOGEN-ACTIVATED PROTEIN KINASE AND NUCLEAR FACTOR-KAPPAB PATHWAYS WAS UNAFFECTED BY I-BET151, AS WAS THE HISTONE ACETYLATION STATUS, AND NEW PROTEIN SYNTHESIS WAS NOT REQUIRED FOR THE ANTI-INFLAMMATORY EFFECTS OF BET INHIBITION. I-BET151 AND JQ1 ALSO SUPPRESSED EXPRESSION OF INFLAMMATORY CYTOKINES, CHEMOKINES, AND OSTEOCLASTOGENIC MEDIATORS IN GFS AND TIGKS INFECTED WITH THE KEY PERIODONTAL PATHOGEN PORPHYROMONAS GINGIVALIS. NOTABLY, P. GINGIVALIS INTERNALIZATION AND INTRACELLULAR SURVIVAL IN GFS AND TIGKS REMAINED UNAFFECTED BY BET INHIBITORS. FINALLY, INHIBITION OF BET PROTEINS SIGNIFICANTLY REDUCED P. GINGIVALIS-INDUCED INFLAMMATORY MEDIATOR EXPRESSION IN GECS AND GFS FROM PATIENTS WITH PERIODONTITIS. OUR RESULTS DEMONSTRATE THAT BET INHIBITORS MAY BLOCK THE EXCESSIVE INFLAMMATORY MEDIATOR PRODUCTION BY RESIDENT CELLS OF THE GINGIVAL TISSUE AND IDENTIFY THE BET FAMILY OF EPIGENETIC READER PROTEINS AS A POTENTIAL THERAPEUTIC TARGET IN THE TREATMENT OF PERIODONTAL DISEASE. 2019 3 5114 39 PORPHYROMONAS GINGIVALIS LIPOPOLYSACCHARIDE STIMULATION IN HUMAN PERIODONTAL LIGAMENT STEM CELLS: ROLE OF EPIGENETIC MODIFICATIONS TO THE INFLAMMATION. PERIODONTITIS IS A CHRONIC ORAL INFLAMMATORY DISEASE PRODUCED BY BACTERIA. GINGIVAL RETRACTION AND BONE AND CONNECTIVE TISSUES RESORPTION ARE THE HALLMARKS OF THIS DISEASE. CHRONIC PERIODONTITIS MAY CONTRIBUTE TO THE RISK OF ONSET OR PROGRESSION OF NEUROINFLAMMATORY PATHOLOGICAL CONDITIONS, SUCH AS ALZHEIMER'S DISEASE. THE MAIN GOAL OF THE PRESENT STUDY WAS TO INVESTIGATE IF THE ROLE OF EPIGENETIC MODULATIONS IS INVOLVED IN PERIODONTITIS USING HUMAN PERIODONTAL LIGAMENT STEM CELLS (HPDLSCS) AS AN IN VITRO MODEL SYSTEM. HPDLSCS WERE TREATED WITH LIPOPOLYSACCHARIDE OF PORPHYROMONAS GINGIVALIS AND THE EXPRESSION OF PROTEINS ASSOCIATED WITH DNA METHYLATION AND HISTONE ACETYLATION, SUCH AS DNMT1 AND P300, RESPECTIVELY, AND INFLAMMATORY TRANSCRIPTION FACTOR NF-KB, WERE EXAMINED. IMMUNOFLUORESCENCE, WESTERN BLOT AND NEXT GENERATION SEQUENCING RESULTS DEMONSTRATED THAT P. GINGIVALIS LIPOPOLYSACCHARIDE SIGNIFICANTLY REDUCED DNA METHYLASE DNMT1, WHILE IT MARKEDLY UPREGULATED THE LEVEL OF HISTONE ACETYLTRANSFERASE P300 AND NF-KB IN HPDLSCS. OUR RESULTS SHOWED THAT P. GINGIVALIS LIPOPOLYSACCHARIDE MARKEDLY REGULATE THE GENES INVOLVED IN EPIGENETIC MECHANISM, WHICH MAY RESULT IN INFLAMMATION INDUCTION. WE PROPOSE THAT P. GINGIVALIS LIPOPOLYSACCHARIDE-TREATED HPDLSCS COULD BE A POTENTIAL IN VITRO MODEL SYSTEM TO STUDY EPIGENETICS MODULATIONS ASSOCIATED WITH PERIODONTITIS, WHICH MIGHT BE HELPFUL TO IDENTIFY NOVEL BIOMARKERS LINKED TO THIS ORAL INFLAMMATORY DISEASE. 2017 4 3323 43 HISTONE DEACETYLASE 1 (HDAC1): A KEY PLAYER OF T CELL-MEDIATED ARTHRITIS. RHEUMATOID ARTHRITIS (RA) REPRESENTS A CHRONIC T CELL-MEDIATED INFLAMMATORY AUTOIMMUNE DISEASE. STUDIES HAVE SHOWN THAT EPIGENETIC MECHANISMS CONTRIBUTE TO THE PATHOGENESIS OF RA. HISTONE DEACETYLASES (HDACS) REPRESENT ONE IMPORTANT GROUP OF EPIGENETIC REGULATORS. HOWEVER, THE ROLE OF INDIVIDUAL HDAC MEMBERS FOR THE PATHOGENESIS OF ARTHRITIS IS STILL UNKNOWN. IN THIS STUDY WE DEMONSTRATE THAT MICE WITH A T CELL-SPECIFIC DELETION OF HDAC1 (HDAC1-CKO) ARE RESISTANT TO THE DEVELOPMENT OF COLLAGEN-INDUCED ARTHRITIS (CIA), WHEREAS THE ANTIBODY RESPONSE TO COLLAGEN TYPE II WAS UNDISTURBED, INDICATING AN UNALTERED T CELL-MEDIATED B CELL ACTIVATION. THE INFLAMMATORY CYTOKINES IL-17 AND IL-6 WERE SIGNIFICANTLY DECREASED IN SERA OF HDAC1-CKO MICE. IL-6 TREATED HDAC1-DEFICIENT CD4(+) T CELLS SHOWED AN IMPAIRED UPREGULATION OF CCR6. SELECTIVE INHIBITION OF CLASS I HDACS WITH THE HDAC INHIBITOR MS-275 UNDER TH17-SKEWING CONDITIONS INHIBITED THE UPREGULATION OF CHEMOKINE RECEPTOR 6 (CCR6) IN MOUSE AND HUMAN CD4(+) T CELLS. ACCORDINGLY, ANALYSIS OF HUMAN RNA-SEQUENCING (RNA-SEQ) DATA AND HISTOLOGICAL ANALYSIS OF SYNOVIAL TISSUE SAMPLES FROM HUMAN RA PATIENTS REVEALED THE EXISTENCE OF CD4(+)CCR6(+) CELLS WITH ENHANCED HDAC1 EXPRESSION. OUR DATA INDICATE A KEY ROLE FOR HDAC1 FOR THE PATHOGENESIS OF CIA AND SUGGEST THAT HDAC1 AND OTHER CLASS I HDACS MIGHT BE PROMISING TARGETS OF SELECTIVE HDAC INHIBITORS (HDACI) FOR THE TREATMENT OF RA. 2020 5 172 38 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 6 2068 35 EPIGENETIC CONTROL OF MICROSOMAL PROSTAGLANDIN E SYNTHASE-1 BY HDAC-MEDIATED RECRUITMENT OF P300. NONSTEROIDAL ANTI-INFLAMMATORY DRUGS ARE THE MOST WIDELY USED MEDICINE TO TREAT PAIN AND INFLAMMATION, AND TO INHIBIT PLATELET FUNCTION. UNDERSTANDING THE EXPRESSION REGULATION OF ENZYMES OF THE PROSTANOID PATHWAY IS OF GREAT MEDICAL RELEVANCE. HISTONE ACETYLATION CRUCIALLY CONTROLS GENE EXPRESSION. WE SET OUT TO IDENTIFY THE IMPACT OF HISTONE DEACETYLASES (HDACS) ON THE GENERATION OF PROSTANOIDS AND EXAMINE THE CONSEQUENCES ON VASCULAR FUNCTION. HDAC INHIBITION (HDACI) WITH THE PAN-HDAC INHIBITOR, VORINOSTAT, ATTENUATED PROSTAGLANDIN (PG)E(2) GENERATION IN THE MURINE VASCULATURE AND IN HUMAN VASCULAR SMOOTH MUSCLE CELLS. IN LINE WITH THIS, THE EXPRESSION OF THE KEY ENZYME FOR PGE(2) SYNTHESIS, MICROSOMAL PGE SYNTHASE-1 (PTGES1), WAS REDUCED BY HDACI. ACCORDINGLY, THE RELAXATION TO ARACHIDONIC ACID WAS DECREASED AFTER EX VIVO INCUBATION OF MURINE VESSELS WITH HDACI. TO IDENTIFY THE UNDERLYING MECHANISM, CHROMATIN IMMUNOPRECIPITATION (CHIP) AND CHIP-SEQUENCING ANALYSIS WERE PERFORMED. THESE RESULTS SUGGEST THAT HDACS ARE INVOLVED IN THE RECRUITMENT OF THE TRANSCRIPTIONAL ACTIVATOR P300 TO THE PTGES1 GENE AND THAT HDACI PREVENTED THIS EFFECT. IN LINE WITH THE ACETYLTRANSFERASE ACTIVITY OF P300, H3K27 ACETYLATION WAS REDUCED AFTER HDACI AND RESULTED IN THE FORMATION OF HETEROCHROMATIN IN THE PTGES1 GENE. IN CONCLUSION, HDAC ACTIVITY MAINTAINS PTGES1 EXPRESSION BY RECRUITING P300 TO ITS GENE. 2017 7 5975 29 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 8 4302 42 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 9 5995 40 TGFBETA-INDUCED FIBROBLAST ACTIVATION REQUIRES PERSISTENT AND TARGETED HDAC-MEDIATED GENE REPRESSION. TISSUE FIBROSIS IS A CHRONIC DISEASE DRIVEN BY PERSISTENT FIBROBLAST ACTIVATION THAT HAS RECENTLY BEEN LINKED TO EPIGENETIC MODIFICATIONS. HERE, WE SCREENED A SMALL LIBRARY OF EPIGENETIC SMALL-MOLECULE MODULATORS TO IDENTIFY COMPOUNDS CAPABLE OF INHIBITING OR REVERSING TGFBETA-MEDIATED FIBROBLAST ACTIVATION. WE IDENTIFIED PRACINOSTAT, AN HDAC INHIBITOR, AS A POTENT ATTENUATOR OF LUNG FIBROBLAST ACTIVATION AND CONFIRMED ITS EFFICACY IN PATIENT-DERIVED FIBROBLASTS ISOLATED FROM FIBROTIC LUNG TISSUE. MECHANISTICALLY, WE FOUND THAT HDAC-DEPENDENT TRANSCRIPTIONAL REPRESSION WAS AN EARLY AND ESSENTIAL EVENT IN TGFBETA-MEDIATED FIBROBLAST ACTIVATION. TREATMENT OF LUNG FIBROBLASTS WITH PRACINOSTAT BROADLY ATTENUATED TGFBETA-MEDIATED EPIGENETIC REPRESSION AND PROMOTED FIBROBLAST QUIESCENCE. WE CONFIRMED A SPECIFIC ROLE FOR HDAC-DEPENDENT HISTONE DEACETYLATION IN THE PROMOTER REGION OF THE ANTI-FIBROTIC GENE PPARGC1A (PGC1ALPHA) IN RESPONSE TO TGFBETA STIMULATION. FINALLY, WE IDENTIFIED HDAC7 AS A KEY FACTOR WHOSE SIRNA-MEDIATED KNOCKDOWN ATTENUATES FIBROBLAST ACTIVATION WITHOUT ALTERING GLOBAL HISTONE ACETYLATION. TOGETHER, THESE RESULTS PROVIDE NOVEL MECHANISTIC INSIGHT INTO THE ESSENTIAL ROLE HDACS PLAY IN TGFBETA-MEDIATED FIBROBLAST ACTIVATION VIA TARGETED GENE REPRESSION. 2019 10 3339 46 HISTONE DEACETYLASE ISOFORMS DIFFERENTIALLY MODULATE INFLAMMATORY AND AUTOANTIBODY RESPONSES IN A MOUSE MODEL OF MYASTHENIA GRAVIS. MYASTHENIA GRAVIS (MG) IS AN AUTOIMMUNE DISEASE CHARACTERIZED BY CHRONIC MUSCLE FATIGUE AND WEAKNESS CAUSED BY AUTOANTIBODIES AND COMPLEMENT-MEDIATED DAMAGE AT NEUROMUSCULAR JUNCTIONS. HISTONE DEACETYLASES (HDACS) ARE CRUCIAL EPIGENETIC REGULATORS OF PROINFLAMMATORY GENE EXPRESSION; HOWEVER, IT IS UNCLEAR WHETHER HDACS MODULATE CHRONIC INFLAMMATION OR AUTOANTIBODY PRODUCTION ASSOCIATED WITH MG PATHOGENESIS. WE EXAMINED EXPRESSION PROFILES AND SERUM LEVELS OF KEY INFLAMMATORY CYTOKINES (IL-6 AND IL-21) AND ACETYLCHOLINE RECEPTOR (ACHR)-SPECIFIC AUTOANTIBODIES FOLLOWING PHARMACOLOGICAL INHIBITION OF KEY HDAC ISOFORMS IN A MOUSE MODEL OF MG. WE FOUND THAT HDAC INHIBITION SIGNIFICANTLY REDUCED THE PRODUCTION OF IL-6, BUT NOT IL-21, IN ACHR-STIMULATED PBMCS AND SPLENOCYTES (N = 5 PER GROUP). TRICHOSTATIN (PAN-HDAC INHIBITOR) TREATMENT OF MG-PBMCS (N = 2) ALSO EXHIBITED REDUCED PRODUCTION OF INDUCED IL-6. ALTHOUGH HDAC1 INHIBITION LOWERED IL-6 LEVELS THE MOST, HDAC2 INHIBITION DEPLETED INTRACELLULAR IL-6 AND MARKEDLY REDUCED SERUM ANTI-ACHR IGG2B IN EAMG MICE. THE TRANSCRIPTOMIC PROFILING AND PATHWAY MAPPING ALSO REVEALED THAT AUTOIMMUNITY-LINKED, MAJOR CELL SIGNALING PATHWAYS WERE DIFFERENTIALLY ALTERED BY HDAC1/2 INHIBITION. HDAC INHIBITION-MEDIATED REDUCTION IN IL-6 AND AUTOANTIBODY LEVELS ALSO CORRELATED WITH MILDER DISEASE AND PRESERVATION OF MUSCLE ACHR IN THE TREATED MICE. OVERALL, OUR FINDINGS REVEALED ISOFORM-SPECIFIC FUNCTIONAL VARIANCE OF HDACS IN REDUCING INFLAMMATION AND IDENTIFIED HDAC-REGULATED MANY GENES UNDERLYING SPECIFIC INFLAMMATORY AND AUTOANTIBODY PATHWAYS IN EAMG. THUS, THE STUDY PROVIDES A RATIONALE FOR FURTHER RESEARCH TO EVALUATE THE HDACS OR THEIR GENE TARGETS AS A POTENTIAL ADJUNCT TREATMENT FOR MG. 2021 11 1036 35 CLASS I HISTONE DEACETYLASES REGULATE P53/NF-KAPPAB CROSSTALK IN CANCER CELLS. THE TRANSCRIPTION FACTORS NF-KAPPAB AND P53 AS WELL AS THEIR CROSSTALK DETERMINE THE FATE OF TUMOR CELLS UPON THERAPEUTIC INTERVENTIONS. REPLICATIVE STRESS AND CYTOKINES PROMOTE SIGNALING CASCADES THAT LEAD TO THE CO-REGULATION OF P53 AND NF-KAPPAB. CONSEQUENTLY, NUCLEAR P53/NF-KAPPAB SIGNALING COMPLEXES ACTIVATE NF-KAPPAB-DEPENDENT SURVIVAL GENES. THE 18 HISTONE DEACETYLASES (HDACS) ARE EPIGENETIC MODULATORS THAT FALL INTO FOUR CLASSES (I-IV). INHIBITORS OF HISTONE DEACETYLASES (HDACI) BECOME INCREASINGLY APPRECIATED AS ANTI-CANCER AGENTS. BASED ON THEIR EFFECTS ON P53 AND NF-KAPPAB, WE ADDRESSED WHETHER CLINICALLY RELEVANT HDACI AFFECT THE NF-KAPPAB/P53 CROSSTALK. THE CHEMOTHERAPEUTICS HYDROXYUREA, ETOPOSIDE, AND FLUDARABINE HALT CELL CYCLE PROGRESSION, INDUCE DNA DAMAGE, AND LEAD TO DNA FRAGMENTATION. THESE AGENTS CO-INDUCE P53 AND NF-KAPPAB-DEPENDENT GENE EXPRESSION IN CELL LINES FROM BREAST AND COLON CANCER AND IN PRIMARY CHRONIC LYMPHATIC LEUKEMIA (CLL) CELLS. USING SPECIFIC HDACI, WE FIND THAT THE CLASS I SUBGROUP OF HDACS, BUT NOT THE CLASS IIB DEACETYLASE HDAC6, ARE REQUIRED FOR THE HYDROXYUREA-INDUCED CROSSTALK BETWEEN P53 AND NF-KAPPAB. HDACI DECREASE THE BASAL AND STRESS-INDUCED EXPRESSION OF P53 AND BLOCK NF-KAPPAB-REGULATED GENE EXPRESSION. WE FURTHER SHOW THAT CLASS I HDACI INDUCE SENESCENCE IN PANCREATIC CANCER CELLS WITH MUTANT P53. 2017 12 5088 42 PIPERLONGUMINE REGULATES EPIGENETIC MODULATION AND ALLEVIATES PSORIASIS-LIKE SKIN INFLAMMATION VIA INHIBITION OF HYPERPROLIFERATION AND INFLAMMATION. PSORIASIS IS AN AUTOIMMUNE SKIN DISEASE, WHERE CHRONIC IMMUNE RESPONSES DUE TO EXAGGERATED CYTOKINE SIGNALING, ABNORMAL DIFFERENTIATION, AND EVASION OF KERATINOCYTES APOPTOSIS PLAYS A CRUCIAL ROLE IN MEDIATING ABNORMAL KERATINOCYTES HYPERPROLIFERATION. FROM THE THERAPEUTIC PERSPECTIVE, THE MOLECULES WITH STRONG ANTI-PROLIFERATIVE AND ANTI-INFLAMMATORY PROPERTIES COULD HAVE TREMENDOUS RELEVANCE. IN THIS STUDY, WE DEMONSTRATED THAT PIPERLONGUMINE (PPL) TREATMENT EFFECTIVELY ABROGATED THE HYPERPROLIFERATION AND DIFFERENTIATION OF KERATINOCYTES BY INDUCING ROS-MEDIATED LATE APOPTOSIS WITH LOSS OF MITOCHONDRIAL MEMBRANE POTENTIAL. BESIDES, THE ARREST OF CELL CYCLE WAS FOUND AT SUB-G1 PHASE AS A RESULT OF DNA FRAGMENTATION. MOLECULARLY, INHIBITION OF STAT3 AND AKT SIGNALING WAS OBSERVED WITH A DECREASE IN PROLIFERATIVE MARKERS SUCH AS PCNA, KI67, AND CYCLIN D1 ALONG WITH ANTI-APOPTOTIC BCL-2 PROTEIN EXPRESSION. KERATIN 17 IS A CRITICAL REGULATOR OF KERATINOCYTE DIFFERENTIATION, AND IT WAS FOUND TO BE DOWNREGULATED WITH PPL SIGNIFICANTLY. FURTHERMORE, PROMINENT ANTI-INFLAMMATORY EFFECTS WERE OBSERVED BY INHIBITION OF LIPOPOLYSACCHARIDE (LPS)/IMIQUIMOD (IMQ)-INDUCED P65 NF-KAPPAB SIGNALING CASCADE AND STRONGLY INHIBITED THE PRODUCTION OF CYTOKINE STORM INVOLVED IN PSORIASIS-LIKE SKIN INFLAMMATION, THUS LED TO THE RESTORATION OF NORMAL EPIDERMAL ARCHITECTURE WITH REDUCTION OF EPIDERMAL HYPERPLASIA AND SPLENOMEGALY. IN ADDITION, PPL EPIGENETICALLY INHIBITED HISTONE-MODIFYING ENZYMES, WHICH INCLUDE HISTONE DEACETYLASES (HDACS) OF CLASS I (HDAC1-4) AND CLASS II (HDAC6) EVALUATED BY IMMUNOBLOTTING AND HDAC ENZYME ASSAY KIT. IN ADDITION, OUR RESULTS SHOW THAT PPL EFFECTIVELY INHIBITS THE NUCLEAR TRANSLOCATION OF P65 AND A HISTONE MODULATOR HDAC3, THUS SEQUESTERED IN THE CYTOPLASM OF MACROPHAGES. FURTHERMORE, PPL EFFECTIVELY ENHANCED THE PROTEIN-PROTEIN INTERACTIONS OF HDAC3 AND P65 WITH IKAPPABALPHA, WHICH WAS DISRUPTED BY LPS STIMULATION AND WERE EVALUATED BY CO-IP AND MOLECULAR MODELING. COLLECTIVELY, OUR FINDINGS INDICATE THAT PIPERLONGUMINE MAY SERVE AS AN ANTI-PROLIFERATIVE AND ANTI-INFLAMMATORY AGENT AND COULD SERVE AS A POTENTIAL THERAPEUTIC OPTION IN TREATING PSORIASIS. 2020 13 3527 33 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 14 3720 34 INHIBITION OF CLASS I HISTONE DEACETYLASES ABROGATES TUMOR GROWTH FACTOR BETA EXPRESSION AND DEVELOPMENT OF FIBROSIS DURING CHRONIC PANCREATITIS. PANCREATIC FIBROSIS IS THE HALLMARK OF CHRONIC PANCREATITIS, A HIGHLY DEBILITATING DISEASE FOR WHICH THERE IS CURRENTLY NO CURE. THE KEY EVENT AT THE BASIS OF PANCREATIC FIBROSIS IS THE DEPOSITION OF EXTRACELLULAR MATRIX PROTEINS BY ACTIVATED PANCREATIC STELLATE CELLS (PSCS). TRANSFORMING GROWTH FACTOR BETA (TGFBETA) IS A POTENT PROFIBROTIC FACTOR IN THE PANCREAS AS IT PROMOTES THE ACTIVATION OF PSC; THUS, PHARMACOLOGIC INTERVENTIONS THAT EFFECTIVELY REDUCE TGFBETA EXPRESSION HARBOR CONSIDERABLE THERAPEUTIC POTENTIAL IN THE TREATMENT OF CHRONIC PANCREATITIS. IN THIS STUDY, WE INVESTIGATED WHETHER TGFBETA EXPRESSION IS REDUCED BY PHARMACOLOGIC INHIBITION OF THE EPIGENETIC MODIFIERS HISTONE DEACETYLASES (HDACS). TO ADDRESS THIS AIM, CHRONIC PANCREATITIS WAS INDUCED IN C57BL/6 MICE WITH SERIAL INJECTIONS OF CERULEIN, AND THE SELECTIVE CLASS 1 HDAC INHIBITOR MS-275 WAS ADMINISTERED IN VIVO IN A PREVENTIVE AND THERAPEUTIC MANNER. BOTH MS-275 REGIMENS POTENTLY REDUCED DEPOSITION OF EXTRACELLULAR MATRIX AND DEVELOPMENT OF FIBROSIS IN THE PANCREAS AFTER 4 WEEKS OF CHRONIC PANCREATITIS. REDUCED PANCREATIC FIBROSIS WAS CONCOMITANT WITH LOWER EXPRESSION OF PANCREATIC TGFBETA AND CONSEQUENT REDUCED PSC ACTIVATION. IN SEARCH OF THE CELL TYPES TARGETED BY THE INHIBITOR, WE FOUND THAT MS-275 TREATMENT ABROGATED THE EXPRESSION OF TGFBETA IN ACINAR CELLS STIMULATED BY CERULEIN TREATMENT. OUR STUDY DEMONSTRATES THAT MS-275 IS AN EFFECTIVE ANTIFIBROTIC AGENT IN THE CONTEXT OF EXPERIMENTAL CHRONIC PANCREATITIS AND THUS MAY CONSTITUTE A VALID THERAPEUTIC INTERVENTION FOR THIS SEVERE DISEASE. 2018 15 2228 31 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 16 5972 31 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 17 141 36 ABERRANT DNA METHYLATION OF MTOR PATHWAY GENES PROMOTES INFLAMMATORY ACTIVATION OF IMMUNE CELLS IN DIABETIC KIDNEY DISEASE. DNA METHYLATION HAS BEEN IMPLICATED IN THE PATHOGENESIS OF DIABETIC KIDNEY DISEASE (DKD), BUT THE UNDERLYING MECHANISMS REMAIN UNCLEAR. IN THIS STUDY, WE TESTED THE HYPOTHESIS THAT ABERRANT DNA METHYLATION IN PERIPHERAL IMMUNE CELLS CONTRIBUTES TO DKD PROGRESSION. WE SHOWED THAT LEVELS OF DNA METHYLTRANSFERASE 1 (DNMT1), A KEY ENZYME FOR DNA METHYLATION, WERE INCREASED ALONG WITH INFLAMMATORY ACTIVITY OF PERIPHERAL BLOOD MONONUCLEAR CELLS IN DKD PATIENTS. INHIBITION OF DNMT1 WITH 5-AZA-2'-DEOXYCYTIDINE (5-AZA) MARKEDLY INCREASED THE PROPORTION OF CD4(+)CD25(+) REGULATORY T CELLS IN PERIPHERAL BLOOD MONONUCLEAR CELLS IN CULTURE AND IN DIABETIC ANIMALS. ADOPTIVE TRANSFER OF IMMUNE CELLS FROM 5-AZA-TREATED ANIMALS SHOWED BENEFICIAL EFFECTS ON THE HOST IMMUNE SYSTEM, RESULTING IN A SIGNIFICANT IMPROVEMENT OF DKD. USING GENOME-WIDE DNA METHYLATION ASSAYS, WE IDENTIFIED THE DIFFERENTIALLY METHYLATED CYTOSINES IN THE PROMOTER REGIONS OF MAMMALIAN TARGET OF RAPAMYCIN (MTOR) REGULATORS IN PERIPHERAL BLOOD MONONUCLEAR CELLS OF DIABETIC PATIENTS. FURTHER, MRNA ARRAYS CONFIRMED THE CONSISTENT INDUCTION OF GENES EXPRESSED IN THE MTOR PATHWAY. IMPORTANTLY, DOWN-REGULATION OF DNMT1 EXPRESSION VIA RNA INTERFERENCE RESULTED IN PROMINENT CYTOSINE DEMETHYLATION OF MTOR NEGATIVE REGULATORS AND SUBSEQUENT DECREASE OF MTOR ACTIVITY. LASTLY, MODULATION OF MTOR RESULTED IN CHANGES IN THE EFFECT OF 5-AZA ON DIABETIC IMMUNE CELLS. THUS, UP-REGULATION OF DNMT1 IN DIABETIC IMMUNE CELLS INDUCES ABERRANT CYTOSINE METHYLATION OF THE UPSTREAM REGULATORS OF MTOR, LEADING TO PATHOGENIC ACTIVATION OF THE MTOR PATHWAY AND CONSEQUENT INFLAMMATION IN DIABETIC KIDNEYS. HENCE, THIS STUDY HIGHLIGHTS THERAPEUTIC POTENTIAL OF TARGETING EPIGENETIC EVENTS IN IMMUNE SYSTEM FOR TREATING DKD. 2019 18 3348 41 HISTONE DEACETYLASES MEET MICRORNA-ASSOCIATED MMP-9 EXPRESSION REGULATION IN GLUCOCORTICOID-SENSITIVE AND -RESISTANT CELL LINES. GLUCOCORTICOIDS ARE LARGELY USED IN THE TREATMENT OF INFLAMMATORY PATHOLOGIES AND/OR HEMATOLOGICAL MALIGNANCIES AND REGULATE THE EXPRESSION OF A VARIETY OF GENES INVOLVED IN INFLAMMATION OR METASTASIS SUCH AS MATRIX METALLOPROTEINASES (MMP). LONG-TERM EXPOSURE TO GLUCOCORTICOIDS CAN RESULT IN FAILURE OF RESPONSIVENESS, WHICH IS OFTEN ASSOCIATED WITH AN UNWANTED GENE EXPRESSION. EPIGENETIC MECHANISMS ARE INVOLVED IN GENE EXPRESSION MODULATED AFTER DEVELOPMENT OF GLUCOCORTICOID RESISTANCE BUT HOW THESE MECHANISMS TAKE PLACE MUST BE FURTHER STUDIED. THE EFFECTS OF HDAC INHIBITORS (HDACI) IN A CONTEXT OF GLUCOCORTICOID RESISTANCE ARE STILL NOT WELL UNDERSTOOD AND NEED TO BE FURTHER INVESTIGATED. WE HYPOTHESIZED THAT ACQUIRED GLUCOCORTICOID RESISTANCE ASSOCIATED TO HDACI COULD DISTURBS EPIGENETIC LANDSCAPE, ESPECIALLY MIR EXPRESSION, LEADING TO A MODULATION OF MMP-9 GENE EXPRESSION AND/OR PROTEIN SECRETION, DESCRIBED AS LARGELY INVOLVED IN BONE REMODELING AND TUMOR INVASION IN MULTIPLE MYELOMA. TO THIS AIM, WE USED SENSITIVE RPMI-8226 CELL LINE AND ITS DEXAMETHASONE- AND METHYLPREDNISOLONE-RESISTANT DERIVATIVES. THE RESISTANT CELL LINES DISPLAYED AN 'OPEN CHROMATIN' AND AN MMP-9 OVEREXPRESSION COMPARATIVELY TO THE SENSITIVE CELL LINE. HDACI TREATMENT WITH MS-275 INCREASED EVEN MORE MMP-9 OVEREXPRESSION NOT ONLY AT AN MRNA LEVEL BUT ALSO AT THE PROTEIN LEVEL. WE SHOWED THAT MMP-9 EXPRESSION REGULATION WAS NOT DIRECTLY LINKED WITH HAT/HDAC BALANCE ALTERATIONS BUT RATHER WITH THE DEREGULATION OF MMP-9-TARGETING MIRS. THEN, WE FIRST DEMONSTRATED THAT MIR?149 DOWNREGULATION WAS DIRECTLY INVOLVED IN THE MMP-9 OVEREXPRESSION FOLLOWING A CHRONIC GLUCOCORTICOID EXPOSURE AND THAT MS-275 COULD AMPLIFY THIS OVEREXPRESSION BY INHIBITION OF MIR?149 EXPRESSION AND MIR?520C OVEREXPRESSION. TAKEN TOGETHER, THESE RESULTS INDICATE THAT THE USE OF HDACI IN A CONTEXT OF ACQUIRED GLUCOCORTICOID RESISTANCE COULD MODIFY THE EPIGENETIC LANDSCAPE, HIGHLIGHTING THE IMPORTANCE OF TAKING THE GLUCOCORTICOID RESPONSE STATUS INTO CONSIDERATION IN TREATMENT WITH HDACI. 2017 19 3193 43 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 20 3795 32 INTERLEUKIN-6 CONTRIBUTES TO GROWTH IN CHOLANGIOCARCINOMA CELLS BY ABERRANT PROMOTER METHYLATION AND GENE EXPRESSION. THE ASSOCIATION BETWEEN CHRONIC INFLAMMATION AND THE DEVELOPMENT AND PROGRESSION OF MALIGNANCY IS EXEMPLIFIED IN THE BILIARY TRACT WHERE PERSISTENT INFLAMMATION STRONGLY PREDISPOSES TO CHOLANGIOCARCINOMA. THE INFLAMMATORY CYTOKINE INTERLEUKIN-6 (IL-6) ENHANCES TUMOR GROWTH IN CHOLANGIOCARCINOMA BY ALTERED GENE EXPRESSION VIA AUTOCRINE MECHANISMS. IL-6 CAN REGULATE THE ACTIVITY OF DNA METHYLTRANSFERASES, AND MOREOVER, ABERRANT DNA METHYLATION CAN CONTRIBUTE TO CARCINOGENESIS. WE THEREFORE INVESTIGATED THE EFFECT OF CHRONIC EXPOSURE TO IL-6 ON METHYLATION-DEPENDENT GENE EXPRESSION AND TRANSFORMED CELL GROWTH IN HUMAN CHOLANGIOCARCINOMA. THE RELATIONSHIP BETWEEN AUTOCRINE IL-6 PATHWAYS, DNA METHYLATION, AND TRANSFORMED CELL GROWTH WAS ASSESSED USING MALIGNANT CHOLANGIOCYTES STABLY TRANSFECTED TO OVEREXPRESS IL-6. TREATMENT WITH THE DNA METHYLATION INHIBITOR 5-AZA-2'-DEOXYCYTIDINE DECREASED CELL PROLIFERATION, GROWTH IN SOFT AGAR, AND METHYLCYTOSINE CONTENT OF MALIGNANT CHOLANGIOCYTES. HOWEVER, THIS EFFECT WAS NOT OBSERVED IN IL-6-OVEREXPRESSING CELLS. IL-6 OVEREXPRESSION RESULTED IN THE ALTERED EXPRESSION AND PROMOTER METHYLATION OF SEVERAL GENES, INCLUDING THE EPIDERMAL GROWTH FACTOR RECEPTOR (EGFR). EGFR PROMOTER METHYLATION WAS DECREASED AND GENE AND PROTEIN EXPRESSION WAS INCREASED BY IL-6. THUS, EPIGENETIC REGULATION OF GENE EXPRESSION BY IL-6 CAN CONTRIBUTE TO TUMOR PROGRESSION BY ALTERING PROMOTER METHYLATION AND GENE EXPRESSION OF GROWTH-REGULATORY PATHWAYS, SUCH AS THOSE INVOLVING EGFR. MOREOVER, ENHANCED IL-6 EXPRESSION MAY DECREASE THE SENSITIVITY OF TUMOR CELLS TO THERAPEUTIC TREATMENTS USING METHYLATION INHIBITORS. THESE OBSERVATIONS HAVE IMPORTANT IMPLICATIONS FOR CANCER TREATMENT AND PROVIDE A MECHANISM BY WHICH PERSISTENT CYTOKINE STIMULATION CAN PROMOTE TUMOR GROWTH. 2006