1 5868 127 SUPPRESSIVE EFFECTS OF METFORMIN ON T-HELPER 1-RELATED CHEMOKINES EXPRESSION IN THE HUMAN MONOCYTIC LEUKEMIA CELL LINE THP-1. PURPOSE OF THE STUDY: TYPE 1 AND TYPE 2 DIABETES MELLITUS (DM) ARE CHRONIC T-CELL-MEDIATED INFLAMMATORY DISEASES. METFORMIN IS A WIDELY USED DRUG FOR TYPE 2 DM THAT REDUCES THE NEED FOR INSULIN IN TYPE 1 DM. HOWEVER, WHETHER METFORMIN HAS AN ANTI-INFLAMMATORY EFFECT FOR TREATING DM IS UNKNOWN. WE INVESTIGATED THE ANTI-INFLAMMATORY MECHANISM OF METFORMIN IN THE HUMAN MONOCYTIC LEUKEMIA CELL LINE THP-1. MATERIALS AND METHODS: THE HUMAN MONOCYTIC LEUKEMIA CELL LINE THP-1 WAS PRETREATED WITH METFORMIN AND STIMULATED WITH LIPOPOLYSACCHARIDE (LPS). THE PRODUCTION OF T-HELPER (TH)-1-RELATED CHEMOKINES INCLUDING INTERFERON-GAMMA-INDUCED PROTEIN-10 (IP-10) AND MONOCYTE CHEMOATTRACTANT PROTEIN-1 (MCP-1), TH2-RELATED CHEMOKINE MACROPHAGE-DERIVED CHEMOKINE, AND THE PROINFLAMMATORY CHEMOKINE TUMOR NECROSIS FACTOR-ALPHA WAS MEASURED USING ENZYME-LINKED IMMUNOSORBENT ASSAY. INTRACELLULAR SIGNALING PATHWAYS WERE INVESTIGATED USING WESTERN BLOT ANALYSIS AND CHROMATIN IMMUNOPRECIPITATION ASSAY. RESULTS: METFORMIN SUPPRESSED LPS-INDUCED IP-10 AND MCP-1 PRODUCTION AS WELL AS LPS-INDUCED PHOSPHORYLATION OF C-JUN N-TERMINAL KINASE (JNK), P38, EXTRACELLULAR SIGNAL-REGULATED KINASE (ERK), AND NUCLEAR FACTOR-KAPPA B (NF-KAPPAB). MOREOVER, METFORMIN SUPPRESSED LPS-INDUCED ACETYLATION OF HISTONES H3 AND H4 AT THE IP-10 PROMOTER. CONCLUSIONS: METFORMIN SUPPRESSED THE PRODUCTION OF TH1-RELATED CHEMOKINES IP-10 AND MCP-1 IN THP-1 CELLS. SUPPRESSIVE EFFECTS OF METFORMIN ON IP-10 PRODUCTION MIGHT BE ATTRIBUTED AT LEAST PARTIALLY TO THE JNK, P38, ERK, AND NF-KAPPAB PATHWAYS AS WELL AS TO EPIGENETIC REGULATION THROUGH THE ACETYLATION OF HISTONES H3 AND H4. THESE RESULTS INDICATED THE THERAPEUTIC ANTI-INFLAMMATORY POTENTIAL OF METFORMIN. 2018 2 1667 39 DOWNREGULATION OF PCAF BY MIR-181A/B PROVIDES FEEDBACK REGULATION TO TNF-ALPHA-INDUCED TRANSCRIPTION OF PROINFLAMMATORY GENES IN LIVER EPITHELIAL CELLS. ABERRANT CELLULAR RESPONSES TO PROINFLAMMATORY CYTOKINES, SUCH AS TNF-ALPHA, ARE PATHOGENIC FEATURES IN MOST CHRONIC INFLAMMATORY DISEASES. A VARIETY OF EXTRACELLULAR AND INTRACELLULAR FEEDBACK PATHWAYS HAS EVOLVED TO PREVENT AN INAPPROPRIATE CELLULAR REACTION TO THESE PROINFLAMMATORY CYTOKINES. IN THIS STUDY, WE REPORT THAT TNF-ALPHA TREATMENT OF HUMAN AND MOUSE CHOLANGIOCYTES AND HEPATOCYTES DOWNREGULATED EXPRESSION OF P300/CBP-ASSOCIATED FACTOR (PCAF), A COACTIVATOR AND AN ACETYLTRANSFERASE THAT PROMOTES HISTONE ACETYLATION AND GENE TRANSCRIPTION. OF THESE UPREGULATED MICRORNAS IN TNF-ALPHA-TREATED CELLS, MIR-181A/B (MIR-181A AND MIR-181B) SUPPRESSED TRANSLATION OF PCAF MRNA. FUNCTIONAL MANIPULATION OF MIR-181A/B CAUSED RECIPROCAL ALTERATIONS IN PCAF PROTEIN EXPRESSION IN CULTURED CHOLANGIOCYTES AND HEPATOCYTES. INHIBITION OF MIR-181A/B FUNCTION WITH ANTI-MIRS BLOCKED TNF-ALPHA-INDUCED SUPPRESSION OF PCAF EXPRESSION. PROMOTER RECRUITMENT OF PCAF WAS SHOWN TO BE ASSOCIATED WITH TNF-ALPHA-INDUCED TRANSCRIPTION OF INFLAMMATORY GENES. INTRIGUINGLY, PRETREATMENT OF CELLS WITH TNF-ALPHA INHIBITED TRANSCRIPTION OF INFLAMMATORY GENES IN RESPONSE TO SUBSEQUENT TNF-ALPHA STIMULATION. OVEREXPRESSION OF PCAF OR INHIBITION OF MIR-181A/B FUNCTION WITH ANTI-MIRS ATTENUATED THE INHIBITORY EFFECTS OF TNF-ALPHA PRETREATMENT ON EPITHELIAL INFLAMMATORY RESPONSE TO SUBSEQUENT TNF-ALPHA STIMULATION. DOWNREGULATION OF PCAF AND THE INHIBITORY EFFECTS OF TNF-ALPHA PRETREATMENT ON LIVER EPITHELIAL INFLAMMATORY RESPONSE WERE FURTHER CONFIRMED IN A MOUSE MODEL OF TNF-ALPHA I.P. INJECTION. THESE DATA SUGGEST THAT PCAF IS A TARGET FOR MIR-181A/B, AND DOWNREGULATION OF PCAF BY TNF-ALPHA PROVIDES NEGATIVE FEEDBACK REGULATION TO INFLAMMATORY REACTIONS IN LIVER EPITHELIAL CELLS, A PROCESS THAT MAY BE RELEVANT TO THE EPIGENETIC FINE-TUNING OF EPITHELIAL INFLAMMATORY PROCESSES IN GENERAL. 2012 3 2305 26 EPIGENETIC REGULATION OF CC-CHEMOKINE LIGAND 2 IN NONRESOLVING INFLAMMATION. INFLAMMATION MEDIATED BY THE CROSSTALK BETWEEN LEUKOCYTES AND RESIDENT TISSUE CELLS IS CRUCIAL FOR THE MAINTENANCE OF HOMEOSTASIS. BECAUSE CHEMOKINE LIGANDS AND RECEPTORS, WHICH RECRUIT A VARIETY OF LEUKOCYTES, ARE WIDELY DISTRIBUTED AMONG TISSUES, IT IS IMPORTANT TO UNDERSTAND THE MECHANISMS REGULATING INFLAMMATORY DISEASE. CHEMOKINES SUCH AS CC-CHEMOKINE LIGAND 2 (CCL2) AMPLIFY AND MAINTAIN INFLAMMATION THROUGH CHEMOKINE-CYTOKINE NETWORKS AFTER THE RECRUITMENT OF CIRCULATING LEUKOCYTES. CHEMOKINE-DEPENDENT NONRESOLVING INFLAMMATION OCCURS IN THE PERIPHERAL AND CENTRAL NERVOUS SYSTEMS, AND UNDERLIES SEVERAL INTRACTABLE DISEASES, INCLUDING CANCER AND NEUROPATHIC PAIN. THE CHRONIC UPREGULATION OF CHEMOKINES IS OFTEN MEDIATED BY EPIGENETIC MECHANISMS CONSISTING OF DNA METHYLATION, HISTONE MODIFICATION, AND NUCLEOSOME POSITIONING. IN PARTICULAR, HISTONE ACETYLATION AND METHYLATION HAVE BEEN SHOWN TO PLAY IMPORTANT ROLES IN THE UPREGULATION OF CHEMOKINE EXPRESSION. IN ADDITION TO CCL2, SEVERAL OTHER CHEMOKINES STRONGLY CONTRIBUTE TO NEUROPATHIC PAIN THROUGH EPIGENETIC INDUCTION. CONSEQUENTLY, TARGETING EPIGENETIC CHANGES MAY HAVE THERAPEUTIC POTENTIAL FOR NONRESOLVING INFLAMMATORY DISEASES SUCH AS NEUROPATHIC PAIN. FURTHER RESEARCH INTO THE EPIGENETICS OF INFLAMMATORY DISEASES SHOULD PROMOTE THE DEVELOPMENT OF NOVEL AND EFFECTIVE TREATMENT STRATEGIES FOR INTRACTABLE INFLAMMATORY DISEASES. 2014 4 3323 34 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 6599 29 TWIST1 AND TWIST2 INDUCE HUMAN MACROPHAGE MEMORY UPON CHRONIC INNATE RECEPTOR TREATMENT BY HDAC-MEDIATED DEACETYLATION OF CYTOKINE PROMOTERS. INTESTINAL TISSUES ARE CONTINUOUSLY EXPOSED TO MICROBIAL PRODUCTS THAT STIMULATE PATTERN-RECOGNITION RECEPTORS (PRRS). ONGOING PRR STIMULATION CAN CONFER EPIGENETIC CHANGES IN MACROPHAGES, WHICH CAN THEN REGULATE SUBSEQUENT IMMUNE OUTCOMES AND ADAPTATION TO THE LOCAL ENVIRONMENT. MECHANISMS LEADING TO THESE CHANGES ARE INCOMPLETELY UNDERSTOOD. WE FOUND THAT SHORT-TERM STIMULATION OF THE PRR NOD2 IN PRIMARY HUMAN MONOCYTE-DERIVED MACROPHAGES RESULTED IN INCREASED H3 AND H4 ACETYLATION OF CYTOKINE PROMOTERS, CONSISTENT WITH THE INCREASED CYTOKINE SECRETION OBSERVED. HOWEVER, WITH PROLONGED NOD2 STIMULATION, BOTH THE ACETYLATION AND CYTOKINE SECRETION WERE DRAMATICALLY DECREASED. CHRONIC NOD2 STIMULATION UPREGULATED THE TRANSCRIPTION FACTORS TWIST1 AND TWIST2, WHICH BOUND TO THE PROMOTERS OF THE HISTONE DEACETYLASES HDAC1 AND HDAC3 AND INDUCED HDAC1 AND HDAC3 EXPRESSION. HDAC1 AND HDAC3 THEN MEDIATED HISTONE DEACETYLATION AT CYTOKINE PROMOTERS AND, IN TURN, CYTOKINE DOWNREGULATION UNDER THESE CONDITIONS. SIMILAR REGULATION WAS OBSERVED UPON CHRONIC STIMULATION OF MULTIPLE PRRS. CONSISTENT WITH THE CHRONIC MICROBIAL EXPOSURE IN THE INTESTINAL ENVIRONMENT, TWIST1, TWIST2, HDAC1, AND HDAC3 WERE UPREGULATED IN HUMAN INTESTINAL RELATIVE TO PERIPHERAL MACROPHAGES. IMPORTANTLY, COMPLEMENTING HDAC1 AND HDAC3 IN TWIST1/TWIST2-DEFICIENT MONOCYTE-DERIVED MACROPHAGES RESTORED THE REDUCED HISTONE ACETYLATION ON CYTOKINE PROMOTERS AND THE DECREASED CYTOKINE SECRETION WITH CHRONIC NOD2 STIMULATION. TAKEN TOGETHER, WE IDENTIFY MECHANISMS WHEREIN TWIST1 AND TWIST2 PROMOTE CHROMATIN MODIFICATIONS, RESULTING IN MACROPHAGE INSTRUCTION AND ADAPTATION TO CONDITIONS IN THE INTESTINAL MICROENVIRONMENT. 2019 6 6085 95 THE EFFECTS OF ACARBOSE ON CHEMOKINE AND CYTOKINE PRODUCTION IN HUMAN MONOCYTIC THP-1 CELLS. BACKGROUND AND OBJECTIVES: CHRONIC INFLAMMATION INDUCED BY PROINFLAMMATORY CYTOKINES AND CHEMOKINES IS POSTULATED TO BE INVOLVED IN INSULIN RESISTANCE AND BETA-CELL DYSFUNCTION IN TYPE 2 DIABETES MELLITUS (T2DM). ACARBOSE, THE ALPHA-GLUCOSIDASE INHIBITOR, IS AN ORAL ANTIDIABETIC DRUG FOR T2DM. ACARBOSE SUPPRESSES INFLAMMATORY CYTOKINE PRODUCTION IN PATIENTS WITH T2DM, THOUGH THE UNDERLYING MECHANISMS ARE UNCLEAR. IN THE PRESENT STUDY, WE AIMED TO INVESTIGATE THE ANTI-INFLAMMATORY EFFECTS AND THE EXACT MECHANISMS OF ACARBOSE IN HUMAN MONOCYTIC THP-1 CELLS. METHODS: THP-1 CELLS WERE PRETREATED WITH ACARBOSE AND THEN STIMULATED WITH LIPOPOLYSACCHARIDE (LPS). THE LEVELS OF TH1-RELATED CHEMOKINES, INCLUDING INTERFERON-GAMMA-INDUCIBLE PROTEIN-10 (IP-10), MONOCYTE CHEMOATTRACTANT PROTEIN-1 (MCP-1), TH2-RELATED CHEMOKINE MACROPHAGE-DERIVED CHEMOKINE (MDC), AND PROINFLAMMATORY CYTOKINE TUMOR NECROSIS FACTOR-ALPHA (TNF-ALPHA), WERE DETERMINED BY ENZYME-LINKED IMMUNOSORBENT ASSAY. INTRACELLULAR SIGNALING PATHWAYS WERE EXPLORED BY WESTERN BLOT ANALYSIS AND USING A CHROMATIN IMMUNOPRECIPITATION ASSAY. RESULTS: ACARBOSE SUPPRESSED THE LEVELS OF IP-10, MCP-1, MDC, AND TNF-ALPHA AND DOWNREGULATED PHOSPHORYLATION OF P38, C-JUN N-TERMINAL KINASE (JNK), EXTRACELLULAR SIGNAL-REGULATED KINASE (ERK), AND NUCLEAR FACTOR-KAPPA B-P65 (NF-KAPPAB-P65) IN LPS-STIMULATED THP-1 CELLS. ACARBOSE SUPPRESSED LPS-INDUCED ACETYLATION OF HISTONES H3 (H3) AND H4 IN THE IP-10 AND MCP-1 PROMOTER REGIONS. THESE FINDINGS REVEALED THE SUPPRESSIVE EFFECTS OF ACARBOSE ON IP-10, MCP-1, MDC, AND TNF-ALPHA PRODUCTION IN THP-1 CELLS VIA, AT LEAST PARTIALLY, THE P38, JNK, ERK, AND NF-KAPPAB-P65 PATHWAYS, AS WELL AS THROUGH EPIGENETIC REGULATION VIA HISTONE H3 AND H4 ACETYLATION. CONCLUSION: OUR STUDY POINTS TO THE THERAPEUTIC ANTI-INFLAMMATORY POTENTIAL OF ACARBOSE. 2019 7 841 25 CHEMOKINES FORM NANOPARTICLES WITH DNA AND CAN SUPERINDUCE TLR-DRIVEN IMMUNE INFLAMMATION. CHEMOKINES CONTROL THE MIGRATORY PATTERNS AND POSITIONING OF IMMUNE CELLS TO ORGANIZE IMMUNE RESPONSES TO PATHOGENS. HOWEVER, MANY CHEMOKINES HAVE BEEN ASSOCIATED WITH SYSTEMIC AUTOIMMUNE DISEASES THAT HAVE CHRONIC IFN SIGNATURES. WE REPORT THAT A SERIES OF CHEMOKINES, INCLUDING CXCL4, CXCL10, CXCL12, AND CCL5, CAN SUPERINDUCE TYPE I IFN (IFN-I) BY TLR9-ACTIVATED PLASMACYTOID DCS (PDCS), INDEPENDENTLY OF THEIR RESPECTIVE KNOWN CHEMOKINE RECEPTORS. MECHANISTICALLY, WE SHOW THAT CHEMOKINES SUCH AS CXCL4 MEDIATE TRANSCRIPTIONAL AND EPIGENETIC CHANGES IN PDCS, MOSTLY TARGETED TO THE IFN-I PATHWAYS. WE DESCRIBE THAT CHEMOKINES PHYSICALLY INTERACT WITH DNA TO FORM NANOPARTICLES THAT PROMOTE CLATHRIN-MEDIATED CELLULAR UPTAKE AND DELIVERY OF DNA IN THE EARLY ENDOSOMES OF PDCS. USING TWO SEPARATE MOUSE MODELS OF SKIN INFLAMMATION, WE OBSERVED THE PRESENCE OF CXCL4 ASSOCIATED WITH DNA IN VIVO. THESE DATA REVEAL A NONCANONICAL ROLE FOR CHEMOKINES TO SERVE AS NUCLEIC ACID DELIVERY VECTORS TO MODULATE TLR SIGNALING, WITH IMPLICATIONS FOR THE CHRONIC PRESENCE OF IFN-I BY PDCS IN AUTOIMMUNE DISEASES. 2022 8 589 35 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 9 6111 26 THE EPIGENETIC ARCHITECTURE AT GENE PROMOTERS DETERMINES CELL TYPE-SPECIFIC LPS TOLERANCE. SYNOVIAL FIBROBLASTS (SF) DRIVE INFLAMMATION AND JOINT DESTRUCTION IN CHRONIC ARTHRITIS. HERE WE SHOW THAT SF POSSESS A DISTINCT TYPE OF LPS TOLERANCE COMPARED TO MACROPHAGES AND OTHER TYPES OF FIBROBLASTS. IN SF AND DERMAL FIBROBLASTS, GENES THAT WERE NON-TOLERIZABLE AFTER REPEATED LPS STIMULATION INCLUDED PRO-INFLAMMATORY CYTOKINES, CHEMOKINES AND MATRIX METALLOPROTEINASES, WHEREAS ANTI-VIRAL GENES WERE TOLERIZABLE. IN MACROPHAGES, ALL MEASURED GENES WERE TOLERIZABLE, WHEREAS IN GINGIVAL AND FORESKIN FIBROBLASTS THESE GENES WERE NON-TOLERIZABLE. REPEATED STIMULATION OF SF WITH LPS RESULTED IN LOSS OF ACTIVATING HISTONE MARKS ONLY IN PROMOTERS OF TOLERIZABLE GENES. THE EPIGENETIC LANDSCAPE AT PROMOTERS OF TOLERIZABLE GENES WAS SIMILAR IN UNSTIMULATED SF AND MONOCYTES, WHEREAS THE BASAL CONFIGURATION OF HISTONE MARKS PROFOUNDLY DIFFERED IN GENES THAT WERE NON-TOLERIZABLE IN SF ONLY. OUR DATA SUGGEST THAT THE EPIGENETIC CONFIGURATION AT GENE PROMOTERS REGULATES CELL-SPECIFIC LPS-INDUCED RESPONSES AND PRIMES SF TO SUSTAIN THEIR INFLAMMATORY RESPONSE IN CHRONIC ARTHRITIS. 2017 10 842 32 CHEMOKINES IN CHRONIC PAIN: CELLULAR AND MOLECULAR MECHANISMS AND THERAPEUTIC POTENTIAL. CHRONIC PAIN RESULTING FROM NERVE INJURY, TISSUE INFLAMMATION, AND TUMOR INVASION OR TREATMENT, IS A MAJOR HEALTH PROBLEM IMPACTING THE QUALITY OF LIFE AND PRODUCING A SIGNIFICANT ECONOMIC AND SOCIAL BURDEN. HOWEVER, THE CURRENT ANALGESIC DRUGS INCLUDING NON-STEROIDAL ANTI-INFLAMMATORY DRUGS AND OPIOIDS ARE INADEQUATE TO RELIEVE CHRONIC PAIN DUE TO THE LACK OF EFFICACY OR SEVERE SIDE-EFFECTS. CHEMOKINES ARE A FAMILY OF SMALL SECRETED PROTEINS THAT BIND TO G PROTEIN-COUPLED RECEPTORS TO TRIGGER INTRACELLULAR SIGNALING PATHWAYS AND DIRECT CELL MIGRATION, PROLIFERATION, SURVIVAL, AND INFLAMMATION UNDER HOMEOSTATIC AND PATHOLOGICAL CONDITIONS. ACCUMULATING EVIDENCE SUPPORTS THE IMPORTANT ROLE OF CHEMOKINES AND CHEMOKINE RECEPTORS IN THE PERIPHERAL AND CENTRAL NERVOUS SYSTEM IN MEDIATING CHRONIC PAIN VIA ENHANCING NEUROINFLAMMATION. IN THIS REVIEW, WE FOCUS ON RECENT PROGRESS IN UNDERSTANDING THE COMPREHENSIVE ROLES OF CHEMOKINES AND CHEMOKINE RECEPTORS IN THE GENERATION AND MAINTENANCE OF DIFFERENT TYPES OF CHRONIC PAIN, INCLUDING NEUROPATHIC PAIN, INFLAMMATORY PAIN, CANCER PAIN, AND VISCERAL PAIN. THE CURRENT REVIEW ALSO SUMMARIZES THE UPSTREAM SIGNALING OF TRANSCRIPTIONAL AND EPIGENETIC REGULATION ON THE EXPRESSION OF CHEMOKINES AND CHEMOKINE RECEPTORS AS WELL AS THE DOWNSTREAM SIGNALING OF CHEMOKINE RECEPTORS UNDERLYING CHRONIC PAIN. AS CHRONIC ITCH AND CHRONIC PAIN SHARE SOME COMMON MECHANISMS, WE ALSO DISCUSS THE EMERGING ROLES OF CHEMOKINES AND CHEMOKINE RECEPTORS IN CHRONIC ITCH. TARGETING SPECIFIC CHEMOKINES OR CHEMOKINE RECEPTORS BY SIRNAS, BLOCKING ANTIBODIES, OR SMALL-MOLECULE ANTAGONISTS MAY OFFER NEW THERAPEUTIC POTENTIAL FOR THE MANAGEMENT OF CHRONIC PAIN. 2020 11 3204 32 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 12 1862 31 EMERGENCE OF FIBROBLASTS WITH A PROINFLAMMATORY EPIGENETICALLY ALTERED PHENOTYPE IN SEVERE HYPOXIC PULMONARY HYPERTENSION. PERSISTENT ACCUMULATION OF MONOCYTES/MACROPHAGES IN THE PULMONARY ARTERY ADVENTITIAL/PERIVASCULAR AREAS OF ANIMALS AND HUMANS WITH PULMONARY HYPERTENSION HAS BEEN DOCUMENTED. THE CELLULAR MECHANISMS CONTRIBUTING TO CHRONIC INFLAMMATORY RESPONSES REMAIN UNCLEAR. WE HYPOTHESIZED THAT PERIVASCULAR INFLAMMATION IS PERPETUATED BY ACTIVATED ADVENTITIAL FIBROBLASTS, WHICH, THROUGH SUSTAINED PRODUCTION OF PROINFLAMMATORY CYTOKINES/CHEMOKINES AND ADHESION MOLECULES, INDUCE ACCUMULATION, RETENTION, AND ACTIVATION OF MONOCYTES/MACROPHAGES. WE FURTHER HYPOTHESIZED THAT THIS PROINFLAMMATORY PHENOTYPE IS THE RESULT OF THE ABNORMAL ACTIVITY OF HISTONE-MODIFYING ENZYMES, SPECIFICALLY, CLASS I HISTONE DEACETYLASES (HDACS). PULMONARY ADVENTITIAL FIBROBLASTS FROM CHRONICALLY HYPOXIC HYPERTENSIVE CALVES (TERMED PH-FIBS) EXPRESSED A CONSTITUTIVE AND PERSISTENT PROINFLAMMATORY PHENOTYPE DEFINED BY HIGH EXPRESSION OF IL-1BETA, IL-6, CCL2(MCP-1), CXCL12(SDF-1), CCL5(RANTES), CCR7, CXCR4, GM-CSF, CD40, CD40L, AND VCAM-1. THE PROINFLAMMATORY PHENOTYPE OF PH-FIBS WAS ASSOCIATED WITH EPIGENETIC ALTERATIONS AS DEMONSTRATED BY INCREASED ACTIVITY OF HDACS AND THE FINDINGS THAT CLASS I HDAC INHIBITORS MARKEDLY DECREASED CYTOKINE/CHEMOKINE MRNA EXPRESSION LEVELS IN THESE CELLS. PH-FIBS INDUCED INCREASED ADHESION OF THP-1 MONOCYTES AND PRODUCED SOLUBLE FACTORS THAT INDUCED INCREASED MIGRATION OF THP-1 AND MURINE BONE MARROW-DERIVED MACROPHAGES AS WELL AS ACTIVATED MONOCYTES/MACROPHAGES TO EXPRESS PROINFLAMMATORY CYTOKINES AND PROFIBROGENIC MEDIATORS (TIMP1 AND TYPE I COLLAGEN) AT THE TRANSCRIPTIONAL LEVEL. CLASS I HDAC INHIBITORS MARKEDLY REDUCED THE ABILITY OF PH-FIBS TO INDUCE MONOCYTE MIGRATION AND PROINFLAMMATORY ACTIVATION. THE EMERGENCE OF A DISTINCT ADVENTITIAL FIBROBLAST POPULATION WITH AN EPIGENETICALLY ALTERED PROINFLAMMATORY PHENOTYPE CAPABLE OF RECRUITING, RETAINING, AND ACTIVATING MONOCYTES/MACROPHAGES CHARACTERIZES PULMONARY HYPERTENSION-ASSOCIATED VASCULAR REMODELING AND THUS COULD CONTRIBUTE SIGNIFICANTLY TO CHRONIC INFLAMMATORY PROCESSES IN THE PULMONARY ARTERY WALL. 2011 13 5592 35 ROLE OF TUMOR NECROSIS FACTOR-ALPHA IN THE HUMAN SYSTEMIC ENDOTOXIN-INDUCED TRANSCRIPTOME. TNFALPHA HAS BEEN IMPLICATED IN THE PATHOGENESIS OF VARIOUS INFLAMMATORY DISEASES. DIFFERENT STRATEGIES TO INHIBIT TNFALPHA IN PATIENTS WITH SEPSIS AND CHRONIC INFLAMMATORY CONDITIONS HAVE SHOWN CONTRASTING OUTCOMES. ALTHOUGH TNFALPHA INHIBITORS ARE WIDELY USED IN CLINICAL PRACTICE, THE IMPACT OF TNFALPHA ANTAGONISM ON WHITE BLOOD CELL GENE EXPRESSION PROFILES DURING ACUTE INFLAMMATION IN HUMANS IN VIVO HAS NOT BEEN ASSESSED. WE HERE LEVERAGED THE ESTABLISHED MODEL OF HUMAN ENDOTOXEMIA TO EXAMINE THE EFFECT OF THE TNFALPHA ANTAGONIST, ETANERCEPT, ON THE GENOME-WIDE TRANSCRIPTIONAL RESPONSES IN CIRCULATING LEUKOCYTES INDUCED BY INTRAVENOUS LPS ADMINISTRATION IN MALE SUBJECTS. ETANERCEPT PRE-TREATMENT RESULTED IN A MARKEDLY DAMPENED TRANSCRIPTIONAL RESPONSE TO LPS. GENE CO-EXPRESSION NETWORK ANALYSIS REVEALED THIS LPS-INDUCED TRANSCRIPTOME CAN BE CATEGORIZED AS TNFALPHA RESPONSIVE AND NON-RESPONSIVE MODULES. HIGHLY SIGNIFICANT TNFALPHA RESPONSIVE MODULES INCLUDE NF-KB SIGNALING, ANTIVIRAL RESPONSES AND T-CELL MEDIATED RESPONSES. WITHIN THESE TNFALPHA RESPONSIVE MODULES WE DELINEATE FUNDAMENTAL GENES INVOLVED IN EPIGENETIC MODIFICATIONS, TRANSCRIPTIONAL INITIATION AND ELONGATION. THUS, WE PROVIDE COMPREHENSIVE INFORMATION ABOUT MOLECULAR PATHWAYS THAT MIGHT BE TARGETED BY THERAPEUTIC INTERVENTIONS THAT SEEK TO INHIBIT TNFALPHA ACTIVITY DURING HUMAN INFLAMMATORY DISEASES. 2013 14 4298 24 MICRORNA-146A GOVERNS FIBROBLAST ACTIVATION AND JOINT PATHOLOGY IN ARTHRITIS. SYNOVIAL FIBROBLASTS ARE KEY CELLS ORCHESTRATING THE INFLAMMATORY RESPONSE IN ARTHRITIS. HERE WE DEMONSTRATE THAT LOSS OF MIR-146A, A KEY EPIGENETIC REGULATOR OF THE INNATE IMMUNE RESPONSE, LEADS TO INCREASED JOINT DESTRUCTION IN A TNF-DRIVEN MODEL OF ARTHRITIS BY SPECIFICALLY REGULATING THE BEHAVIOR OF SYNOVIAL FIBROBLASTS. ABSENCE OF MIR-146A IN SYNOVIAL FIBROBLASTS DISPLAY A HIGHLY DEREGULATED GENE EXPRESSION PATTERN AND ENHANCED PROLIFERATION IN VITRO AND IN VIVO. DEFICIENCY OF MIR-146A INDUCES DEREGULATION OF TUMOR NECROSIS FACTOR (TNF) RECEPTOR ASSOCIATED FACTOR 6 (TRAF6) IN SYNOVIAL FIBROBLASTS, LEADING TO INCREASED PROLIFERATION. IN ADDITION, LOSS OF MIR-146A SHIFTS THE METABOLIC STATE OF FIBROBLASTS TOWARDS GLYCOLYSIS AND AUGMENTS THE ABILITY OF SYNOVIAL FIBROBLASTS TO SUPPORT THE GENERATION OF OSTEOCLASTS BY CONTROLLING THE BALANCE OF OSTEOCLASTOGENIC REGULATORY FACTORS RECEPTOR ACTIVATOR OF NF-KAPPAB LIGAND (RANKL) AND OSTEOPROTEGERIN (OPG). BONE MARROW TRANSPLANTATION EXPERIMENTS CONFIRMED THE IMPORTANCE OF MIR-146A IN THE RADIORESISTANT MESENCHYMAL COMPARTMENT FOR THE CONTROL OF ARTHRITIS SEVERITY, IN PARTICULAR FOR INFLAMMATORY JOINT DESTRUCTION. THIS STUDY THEREFORE IDENTIFIES MICRORNA-146A AS AN IMPORTANT LOCAL EPIGENETIC REGULATOR OF THE INFLAMMATORY RESPONSE IN ARTHRITIS. IT IS A CENTRAL ELEMENT OF AN ANTI-INFLAMMATORY FEEDBACK LOOP IN RESIDENT SYNOVIAL FIBROBLASTS, WHO ARE ORCHESTRATING THE INFLAMMATORY RESPONSE IN CHRONIC ARTHRITIS. MIR-146A RESTRICTS THEIR ACTIVATION, THEREBY PREVENTING EXCESSIVE TISSUE DAMAGE DURING ARTHRITIS. 2017 15 6110 26 THE EPIGENETIC ALTERATION OF SYNOVIAL CELL GENE EXPRESSION IN RHEUMATOID ARTHRITIS AND THE ROLES OF NUCLEAR FACTOR KAPPAB AND NOTCH SIGNALING PATHWAYS. RHEUMATOID ARTHRITIS (RA) IS A COMPLEX PROCESS OF CHRONIC AND PROGRESSIVE INFLAMMATION ASSOCIATED WITH ACTIVATION OF NUMEROUS SIGNALING MOLECULES AND TRANSCRIPTION FACTORS AND HYPERPROLIFERATION OF SYNOVIOCYTES OF THE AFFECTED JOINTS, ALTHOUGH THE GREATER PART OF ITS PATHOPHYSIOLOGICAL PROCESS IS EXPLAINED BY ACTIVATION OF NUCLEAR FACTOR KAPPAB (NF-KAPPAB). FOR EXAMPLE, THE SELF-PERPETUATING NATURE OF THE RHEUMATOID INFLAMMATION IS ASCRIBABLE TO OVEREXPRESSION OF THE PROINFLAMMATORY CYTOKINES TUMOR NECROSIS FACTOR ALPHA AND INTERLEUKIN-1BETA, KNOWN TO ELICIT THE ACTIVATION CASCADE FOR NF-KAPPAB AND ACTIVATOR PROTEIN-1 THAT ARE RESPONSIBLE FOR TRANSCRIPTIONAL INDUCTION OF THESE CYTOKINES AMONG OTHER TARGET GENES, WHICH CONFORM A POSITIVE FEEDBACK LOOP FOR CONTINUATION AND EXPANSION OF THE INFLAMMATORY RESPONSES. IN ADDITION, COMPARATIVE GENE EXPRESSION PROFILE ANALYSES HAVE REVEALED ACTIVATION OF A NUMBER OF GENES THAT EXPLAIN THE "TRANSFORMED-LIKE" PHENOTYPE OF SYNOVIOCYTES. AMONG THE GENES EXPRESSED IN RHEUMATOID SYNOVIOCYTES UPON INFLAMMATORY STIMULI, INDUCTION OF GENE EXPRESSION OF NOTCH PROTEINS AND ITS LIGAND HAVE BEEN FOUND. POSSIBLE ROLES OF NOTCH SIGNALING IN RA SYNOVIOCYTES ARE DISCUSSED. 2005 16 5795 29 STAT3 INDUCTION OF MIR-146B FORMS A FEEDBACK LOOP TO INHIBIT THE NF-KAPPAB TO IL-6 SIGNALING AXIS AND STAT3-DRIVEN CANCER PHENOTYPES. INTERLEUKIN-6 (IL-6)-MEDIATED ACTIVATION OF SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION 3 (STAT3) IS A MECHANISM BY WHICH CHRONIC INFLAMMATION CAN CONTRIBUTE TO CANCER AND IS A COMMON ONCOGENIC EVENT. WE DISCOVERED A PATHWAY, THE LOSS OF WHICH IS ASSOCIATED WITH PERSISTENT STAT3 ACTIVATION IN HUMAN CANCER. WE FOUND THAT THE GENE ENCODING THE TUMOR SUPPRESSOR MICRORNA MIR-146B IS A DIRECT STAT3 TARGET GENE, AND ITS EXPRESSION WAS INCREASED IN NORMAL BREAST EPITHELIAL CELLS BUT DECREASED IN TUMOR CELLS. METHYLATION OF THE MIR-146B PROMOTER, WHICH INHIBITED STAT3-MEDIATED INDUCTION OF EXPRESSION, WAS INCREASED IN PRIMARY BREAST CANCERS. MOREOVER, WE FOUND THAT MIR-146B INHIBITED NUCLEAR FACTOR KAPPAB (NF-KAPPAB)-DEPENDENT PRODUCTION OF IL-6, SUBSEQUENT STAT3 ACTIVATION, AND IL-6/STAT3-DRIVEN MIGRATION AND INVASION IN BREAST CANCER CELLS, THEREBY ESTABLISHING A NEGATIVE FEEDBACK LOOP. IN ADDITION, HIGHER EXPRESSION OF MIR-146B WAS POSITIVELY CORRELATED WITH PATIENT SURVIVAL IN BREAST CANCER SUBTYPES WITH INCREASED IL6 EXPRESSION AND STAT3 PHOSPHORYLATION. OUR RESULTS IDENTIFY AN EPIGENETIC MECHANISM OF CROSSTALK BETWEEN STAT3 AND NF-KAPPAB RELEVANT TO CONSTITUTIVE STAT3 ACTIVATION IN MALIGNANCY AND THE ROLE OF INFLAMMATION IN ONCOGENESIS. 2014 17 593 35 BET PROTEIN INHIBITION REGULATES CYTOKINE PRODUCTION AND PROMOTES NEUROPROTECTION AFTER SPINAL CORD INJURY. BACKGROUND: SPINAL CORD INJURY (SCI) USUALLY CAUSES A DEVASTATING LIFELONG DISABILITY FOR PATIENTS. AFTER A TRAUMATIC LESION, DISRUPTION OF THE BLOOD-SPINAL CORD BARRIER INDUCES THE INFILTRATION OF MACROPHAGES INTO THE LESION SITE AND THE ACTIVATION OF RESIDENT GLIAL CELLS, WHICH RELEASE CYTOKINES AND CHEMOKINES. THESE EVENTS RESULT IN A PERSISTENT INFLAMMATION, WHICH HAS BOTH DETRIMENTAL AND BENEFICIAL EFFECTS, BUT EVENTUALLY LIMITS FUNCTIONAL RECOVERY AND CONTRIBUTES TO THE APPEARANCE OF NEUROPATHIC PAIN. BROMODOMAIN AND EXTRA-TERMINAL DOMAIN (BET) PROTEINS ARE EPIGENETIC READERS THAT REGULATE THE EXPRESSION OF INFLAMMATORY GENES BY INTERACTING WITH ACETYLATED LYSINE RESIDUES. WHILE BET INHIBITORS ARE A PROMISING THERAPEUTIC STRATEGY FOR CANCER, LITTLE IS KNOWN ABOUT THEIR IMPLICATION AFTER SCI. THUS, THE CURRENT STUDY WAS AIMED TO INVESTIGATE THE ANTI-INFLAMMATORY ROLE OF BET INHIBITORS IN THIS PATHOLOGIC CONDITION. METHODS: WE EVALUATED THE EFFECTIVENESS OF THE BET INHIBITOR JQ1 TO MODIFY MACROPHAGE REACTIVITY IN VITRO AND TO MODULATE INFLAMMATION IN A SCI MICE MODEL. WE ANALYZED THE EFFECTS OF BET INHIBITION IN PRO-INFLAMMATORY AND ANTI-INFLAMMATORY CYTOKINE PRODUCTION IN VITRO AND IN VIVO. WE DETERMINED THE EFFECTIVENESS OF BET INHIBITION IN TISSUE SPARING, INFLAMMATION, NEURONAL PROTECTION, AND BEHAVIORAL OUTCOME AFTER SCI. RESULTS: WE HAVE FOUND THAT THE BET INHIBITOR JQ1 REDUCED THE LEVELS OF PRO-INFLAMMATORY MEDIATORS AND INCREASED THE EXPRESSION OF ANTI-INFLAMMATORY CYTOKINES. A PROLONGED TREATMENT WITH JQ1 ALSO DECREASED REACTIVITY OF MICROGLIA/MACROPHAGES, ENHANCED NEUROPROTECTION AND FUNCTIONAL RECOVERY, AND ACUTELY REDUCED NEUROPATHIC PAIN AFTER SCI. CONCLUSIONS: BET PROTEIN INHIBITION IS AN EFFECTIVE TREATMENT TO REGULATE CYTOKINE PRODUCTION AND PROMOTE NEUROPROTECTION AFTER SCI. THESE NOVEL RESULTS DEMONSTRATE FOR THE FIRST TIME THAT TARGETING BET PROTEINS IS AN ENCOURAGING APPROACH FOR SCI REPAIR AND A POTENTIAL STRATEGY TO TREAT OTHER INFLAMMATORY PATHOLOGIES. 2019 18 2784 38 EZH2 PROMOTES EXTRACELLULAR MATRIX DEGRADATION VIA NUCLEAR FACTOR-KAPPAB (NF-KAPPAB) AND P38 SIGNALING PATHWAYS IN PULPITIS. PULPITIS IS A COMPLICATED CHRONIC INFLAMMATORY PROCESS WHICH CAN BE IN A DYNAMIC BALANCE BETWEEN DAMAGE AND REPAIR. THE EXTRACELLULAR MATRIX PLAYS AN IMPORTANT REGULATORY ROLE IN WOUND HEALING AND TISSUE REPAIR. THE AIM OF THIS STUDY WAS TO EXPLORE THE ROLE OF THE EPIGENETIC MARK, ENHANCER OF ZESTE HOMOLOG 2 (EZH2) ON THE DEGRADATION OF EXTRACELLULAR MATRIX DURING PULPITIS. QUANTITATIVE POLYMERASE CHAIN REACTION WAS USED TO ASSESS THE EXPRESSION OF MATRIX METALLOPROTEINASES (MMPS) AND TYPE I COLLAGEN IN HUMAN DENTAL PULP CELLS (HDPCS) UPON EZH2 AND EI1 (EZH2 INHIBITOR) STIMULATION. THE MECHANISM OF EZH2 AFFECTING EXTRACELLULAR MATRIX WAS EXPLORED THROUGH QUANTITATIVE POLYMERASE CHAIN REACTION AND WESTERN BLOT. A RAT MODEL OF DENTAL PULP INFLAMMATION WAS ESTABLISHED, AND THE EXPRESSION OF TYPE I COLLAGEN IN DENTAL PULP UNDER EZH2 STIMULATION WAS DETECTED BY IMMUNOHISTOCHEMICAL STAINING. EZH2 UPREGULATED THE EXPRESSION OF MMP-1, MMP-3, MMP-8, AND MMP-10 AND DECREASED THE PRODUCTION OF TYPE I COLLAGEN IN HDPCS, WHILE EI1 HAD THE OPPOSITE EFFECT. EZH2 ACTIVATED THE NUCLEAR FACTOR-KAPPA B (NF-KAPPAB) AND P38 SIGNALING PATHWAYS IN HDPCS, THE INHIBITION OF WHICH REVERSED THE INDUCTION OF MMPS AND THE SUPPRESSION OF TYPE I COLLAGEN. EZH2 CAN DOWNREGULATE THE TYPE I COLLAGEN LEVELS IN AN EXPERIMENTAL MODEL OF DENTAL PULPITIS IN RATS. EZH2 PROMOTES EXTRACELLULAR MATRIX DEGRADATION VIA NUCLEAR FACTOR-KAPPAB (NF-KAPPAB) AND P38 SIGNALING PATHWAYS IN PULPITIS. EZH2 CAN DECREASE THE TYPE I COLLAGEN LEVELS IN VIVO AND IN VITRO. 2021 19 2067 29 EPIGENETIC CONTROL OF MACROPHAGE SHAPE TRANSITION TOWARDS AN ATYPICAL ELONGATED PHENOTYPE BY HISTONE DEACETYLASE ACTIVITY. INFLAMMATORY CHRONIC PATHOLOGIES ARE COMPLEX PROCESSES CHARACTERIZED BY AN IMBALANCE BETWEEN THE RESOLUTION OF THE INFLAMMATORY PHASE AND THE ESTABLISHMENT OF TISSUE REPAIR. THE MAIN PLAYERS IN THESE INFLAMMATORY PATHOLOGIES ARE BONE MARROW DERIVED MONOCYTES (BMDMS). HOWEVER, HOW MONOCYTE DIFFERENTIATION IS MODULATED TO GIVE RISE TO SPECIFIC MACROPHAGE SUBPOPULATIONS (M1 OR M2) THAT MAY EITHER MAINTAIN THE CHRONIC INFLAMMATORY PROCESS OR LEAD TO WOUND HEALING IS STILL UNCLEAR. CONSIDERING THAT INHIBITORS OF HISTONE DEACETYLASE (HDAC) HAVE AN ANTI-INFLAMMATORY ACTIVITY, WE ASKED WHETHER THIS ENZYME WOULD PLAY A ROLE ON MONOCYTE DIFFERENTIATION INTO M1 OR M2 PHENOTYPE AND IN THE CELL SHAPE TRANSITION THAT FOLLOWS. WE THEN INDUCED MURINE BONE MARROW PROGENITORS INTO MONOCYTE/MACROPHAGE DIFFERENTIATION PATHWAY USING MEDIA CONTAINING GM-CSF AND THE HDAC BLOCKER, TRICHOSTATIN A (TSA). WE FOUND THAT THE PHARMACOLOGICAL INHIBITION OF HDAC ACTIVITY LED TO A SHAPE TRANSITION FROM THE TYPICAL MACROPHAGE PANCAKE-LIKE SHAPE INTO AN ELONGATED MORPHOLOGY, WHICH WAS CORRELATED TO A MIXED M1/M2 PROFILE OF CYTOKINE AND CHEMOKINE SECRETION. OUR RESULTS PRESENT, FOR THE FIRST TIME, THAT HDAC ACTIVITY ACTS AS A REGULATOR OF MACROPHAGE DIFFERENTIATION IN THE ABSENCE OF LYMPHOCYTE STIMULI. WE PROPOSE THAT HDAC ACTIVITY DOWN REGULATES MACROPHAGE PLASTICITY FAVORING THE PRO-INFLAMMATORY PHENOTYPE. 2015 20 3789 24 INTERLEUKIN 17 CONTRIBUTES TO THE CHRONICITY OF INFLAMMATORY DISEASES SUCH AS RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC INFLAMMATORY DISEASE LEADING TO JOINT DESTRUCTION AND BONE RESORPTION. THE PROINFLAMMATORY CYTOKINE INTERLEUKIN 17 (IL-17), PRIMARILY PRODUCED BY TH17 CELLS, HAS BEEN SHOWN TO BE INVOLVED IN ALL STAGES OF THE DISEASE AND TO BE AN IMPORTANT CONTRIBUTOR OF RA CHRONICITY. THREE MAJOR PROCESSES DRIVE THE IL-17-MEDIATED CHRONICITY. SEVERAL EPIGENETIC EVENTS, ENHANCED IN RA PATIENTS, LEAD TO THE INCREASED PRODUCTION OF IL-17 BY TH17 CELLS. IL-17 THEN INDUCES THE PRODUCTION OF SEVERAL INFLAMMATORY MEDIATORS IN THE DISEASED SYNOVIUM, WHICH ARE FURTHER SYNERGISTICALLY ENHANCED VIA COMBINATIONS OF IL-17 WITH OTHER CYTOKINES. IL-17 ALSO PROMOTES THE SURVIVAL OF BOTH THE SYNOVIOCYTES AND INFLAMMATORY CELLS AND PROMOTES THE MATURATION OF THESE IMMUNE CELLS. THIS LEADS TO AN INCREASED NUMBER OF SYNOVIOCYTES AND INFLAMMATORY CELLS IN THE SYNOVIAL FLUID AND IN THE SYNOVIUM LEADING TO THE HYPERPLASIA AND EXACERBATED INFLAMMATION OBSERVED IN JOINTS OF RA PATIENTS. FURTHERMORE, THESE IL-17-DRIVEN EVENTS INITIATE SEVERAL FEEDBACK-LOOP MECHANISMS LEADING TO INCREASED EXPANSION OF TH17 CELLS AND THEREBY INCREASED PRODUCTION OF IL-17. IN THIS REVIEW, WE AIM TO DEPICT A COMPLETE PICTURE OF THE IL-17-DRIVEN VICIOUS CIRCLE LEADING TO RA CHRONICITY AND TO PINPOINT THE KEY ASPECTS THAT REQUIRE FURTHER EXPLORATION. 2014