1 6041 87 THE CLASS III HISTONE DEACETYLASE SIRTUIN 1 IN IMMUNE SUPPRESSION AND ITS THERAPEUTIC POTENTIAL IN RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC DEBILITATING DISEASE OF THE JOINTS. BOTH THE INNATE AND ADAPTIVE IMMUNE RESPONSES PARTICIPATE IN THE DEVELOPMENT AND PROGRESSION OF RA. WHILE SEVERAL THERAPEUTIC REAGENTS, SUCH AS TNF-ALPHA AGONISTS, HAVE BEEN SUCCESSFULLY DEVELOPED FOR THE CLINICAL USE IN THE TREATMENT OF RA, MORE THAN HALF OF THE PATIENTS DO NOT RESPOND TO ANTI-TNF THERAPY. THEREFORE, NEW THERAPEUTIC REAGENTS ARE NEEDED. RECENT STUDIES HAVE SHOWN THAT SIRTUIN 1 (SIRT1), A NICOTINAMIDE ADENINE DINUCLEOTIDE (NAD)-DEPENDENT HISTONE DEACETYLASE, IS A CRITICAL NEGATIVE REGULATOR OF BOTH THE INNATE AND ADAPTIVE IMMUNE RESPONSE IN MICE, AND ITS ALTERED FUNCTIONS ARE LIKELY TO BE INVOLVED IN AUTOIMMUNE DISEASES. SMALL MOLECULES THAT MODULATE SIRT1 FUNCTIONS ARE POTENTIAL THERAPEUTIC REAGENTS FOR AUTOIMMUNE INFLAMMATORY DISEASES. THIS REVIEW HIGHLIGHTS THE ROLE OF SIRT1 IN IMMUNE REGULATION AND RA. 2013 2 783 23 CELL-SPECIFIC EPIGENETIC DRIVERS OF PATHOGENESIS IN RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS IS A COMPLEX, INFLAMMATORY AUTOIMMUNE DISEASE, WHICH IS CHARACTERIZED BY PAIN, SWELLING AND JOINT DAMAGE DRIVEN BY THE ALTERED BEHAVIOR OF A NUMBER OF DIFFERENT CELL TYPES SUCH AS SYNOVIAL FIBROBLASTS MACROPHAGES AND LYMPHOCYTES. THE MECHANISM UNDERLYING PATHOGENESIS IS UNCLEAR BUT INCREASING EVIDENCE POINTS TO ALTERED EPIGENETIC REGULATION WITHIN THESE CELL TYPES WHICH PROMOTES THE ACTIVATED DESTRUCTIVE BEHAVIOR THAT UNDERLIES DISEASE PATHOGENESIS. THIS REVIEW SUMMARIZES THE KEY EPIGENETIC MODIFICATIONS IN THE MOST IMPORTANT CELLS TYPES IN RHEUMATOID ARTHRITIS, WHICH ARE ASSOCIATED WITH DISEASE ACTIVITY. WE ALSO DISCUSS EMERGING AVENUES OF RESEARCH FOCUSING ON READERS OF EPIGENETIC MARKERS WHICH MAY SERVE TO BE POTENTIAL THERAPEUTIC TARGETS. 2021 3 1608 36 DNA METHYLATION-GOVERNED GENE EXPRESSION IN AUTOIMMUNE ARTHRITIS. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC INFLAMMATORY AUTOIMMUNE DISEASE HALLMARKED BY PROGRESSIVE AND IRREVERSIBLE JOINT DESTRUCTION. RA PATHOGENESIS IS A T CELL-REGULATED AND B CELL-MEDIATED PROCESS IN WHICH ACTIVATED LYMPHOCYTE-PRODUCED CHEMOKINES AND CYTOKINES PROMOTE LEUKOCYTE INFILTRATION THAT ULTIMATELY LEADS TO DESTRUCTION OF THE JOINTS. THERE IS AN OBVIOUS NEED TO DISCOVER NEW DRUGS FOR RA TREATMENT THAT HAVE DIFFERENT BIOLOGICAL TARGETS OR MODES OF ACTION THAN THE CURRENTLY EMPLOYED THERAPEUTICS. ENVIRONMENTAL FACTORS SUCH AS CIGARETTE SMOKE, CERTAIN DIET COMPONENTS, AND ORAL PATHOGENS CAN SIGNIFICANTLY AFFECT GENE REGULATION VIA EPIGENETIC FACTORS. EPIGENETICS OPENED A NEW FIELD FOR PHARMACOLOGY, AND DNA METHYLATION AND HISTONE MODIFICATION-IMPLICATED FACTORS ARE FEASIBLE TARGETS FOR RA THERAPY. EXPLORING RA PATHOGENESIS INVOLVED EPIGENETIC FACTORS AND MECHANISMS IS CRUCIAL FOR DEVELOPING MORE EFFICIENT RA THERAPIES. HERE WE REVIEW EPIGENETIC ALTERATIONS ASSOCIATED WITH RA PATHOGENESIS INCLUDING DNA METHYLATION AND INTERACTING FACTORS. ADDITIONALLY, WE WILL SUMMARIZE THE LITERATURE REVEALING THE INVOLVED MOLECULAR STRUCTURES AND INTERACTIONS. FINALLY, POTENTIAL EPIGENETIC FACTOR-BASED THERAPIES WILL BE DISCUSSED THAT MAY HELP IN BETTER MANAGEMENT OF RA IN THE FUTURE. 2019 4 6597 30 TUNING MONOCYTES AND MACROPHAGES FOR PERSONALIZED THERAPY AND DIAGNOSTIC CHALLENGE IN RHEUMATOID ARTHRITIS. MONOCYTES/MACROPHAGES PLAY A CENTRAL ROLE IN CHRONIC INFLAMMATORY DISORDERS, INCLUDING RHEUMATOID ARTHRITIS (RA). ACTIVATION OF THESE CELLS RESULTS IN THE PRODUCTION OF VARIOUS MEDIATORS RESPONSIBLE FOR INFLAMMATION AND RA PATHOGENESIS. ON THE OTHER HAND, THE DEPLETION OF MACROPHAGES USING SPECIFIC ANTIBODIES OR CHEMICAL AGENTS CAN PREVENT THEIR SYNOVIAL TISSUE INFILTRATION AND SUBSEQUENTLY ATTENUATES INFLAMMATION. THEIR PLASTICITY IS A MAJOR FEATURE THAT HELPS THE SWITCH FROM A PRO-INFLAMMATORY PHENOTYPE (M1) TO AN ANTI-INFLAMMATORY STATE (M2). THEREFORE, UNDERSTANDING THE PRECISE STRATEGY TARGETING PRO-INFLAMMATORY MONOCYTES/MACROPHAGES SHOULD BE A POWERFUL WAY OF INHIBITING CHRONIC INFLAMMATION AND BONE EROSION. IN THIS REVIEW, WE DEMONSTRATE POTENTIAL CONSEQUENCES OF DIFFERENT EPIGENETIC REGULATIONS ON INFLAMMATORY CYTOKINES PRODUCTION BY MONOCYTES. IN ADDITION, WE PRESENT UNIQUE PROFILES OF MONOCYTES/MACROPHAGES CONTRIBUTING TO IDENTIFICATION OF NEW BIOMARKERS OF DISEASE ACTIVITY OR PREDICTING TREATMENT RESPONSE IN RA. WE ALSO OUTLINE NOVEL APPROACHES OF TUNING MONOCYTES/MACROPHAGES BY BIOLOGIC DRUGS, SMALL MOLECULES OR BY OTHER THERAPEUTIC MODALITIES TO REDUCE ARTHRITIS. FINALLY, THE IMPORTANCE OF CELLULAR HETEROGENEITY OF MONOCYTES/MACROPHAGES IS HIGHLIGHTED BY SINGLE-CELL TECHNOLOGIES, WHICH LEADS TO THE DESIGN OF CELL-SPECIFIC THERAPEUTIC PROTOCOLS FOR PERSONALIZED MEDICINE IN RA IN THE FUTURE. 2021 5 5937 34 TARGETING HISTONE DEACETYLASE ACTIVITY IN RHEUMATOID ARTHRITIS AND ASTHMA AS PROTOTYPES OF INFLAMMATORY DISEASE: SHOULD WE KEEP OUR HATS ON? CELLULAR ACTIVATION, PROLIFERATION AND SURVIVAL IN CHRONIC INFLAMMATORY DISEASES IS REGULATED NOT ONLY BY ENGAGEMENT OF SIGNAL TRANS-DUCTION PATHWAYS THAT MODULATE TRANSCRIPTION FACTORS REQUIRED FOR THESE PROCESSES, BUT ALSO BY EPIGENETIC REGULATION OF TRANSCRIPTION FACTOR ACCESS TO GENE PROMOTER REGIONS. HISTONE ACETYL TRANSFERASES COORDINATE THE RECRUITMENT AND ACTIVATION OF TRANSCRIPTION FACTORS WITH CONFORMATIONAL CHANGES IN HISTONES THAT ALLOW GENE PROMOTER EXPOSURE. HISTONE DEACETYLASES (HDACS) COUNTERACT HISTONE ACETYL TRANSFERASE ACTIVITY THROUGH THE TARGETING OF BOTH HISTONES AS WELL AS NONHISTONE SIGNAL TRANSDUCTION PROTEINS IMPORTANT IN INFLAMMATION. NUMEROUS STUDIES HAVE INDICATED THAT DEPRESSED HDAC ACTIVITY IN PATIENTS WITH INFLAMMATORY AIRWAY DISEASES MAY CONTRIBUTE TO LOCAL PROINFLAMMATORY CYTOKINE PRODUCTION AND DIMINISH PATIENT RESPONSES TO CORTICOSTEROID TREATMENT. RECENT OBSERVATIONS THAT HDAC ACTIVITY IS DEPRESSED IN RHEUMATOID ARTHRITIS PATIENT SYNOVIAL TISSUE HAVE PREDICTED THAT STRATEGIES RESTORING HDAC FUNCTION MAY BE THERAPEUTIC IN THIS DISEASE AS WELL. PHARMACOLOGICAL INHIBITORS OF HDAC ACTIVITY, HOWEVER, HAVE DEMONSTRATED POTENT THERAPEUTIC EFFECTS IN ANIMAL MODELS OF ARTHRITIS AND OTHER CHRONIC INFLAMMATORY DISEASES. IN THE PRESENT REVIEW WE ASSESS AND RECONCILE THESE OUTWARDLY PARADOXICAL STUDY RESULTS TO PROVIDE A WORKING MODEL FOR HOW ALTERATIONS IN HDAC ACTIVITY MAY CONTRIBUTE TO PATHOLOGY IN RHEUMATOID ARTHRITIS, AND HIGHLIGHT KEY QUESTIONS TO BE ANSWERED IN THE PRECLINICAL EVALUATION OF COMPOUNDS MODULATING THESE ENZYMES. 2008 6 3699 26 INFLAMMATORY MEMORIES: IS EPIGENETICS THE MISSING LINK TO PERSISTENT STROMAL CELL ACTIVATION IN RHEUMATOID ARTHRITIS? RHEUMATOID ARTHRITIS (RA) IS A CHRONIC INFLAMMATORY DISEASE LEADING TO JOINT DESTRUCTION. SYNOVIAL FIBROBLASTS ARE RECOGNIZED AS KEY CELLS IN THE PATHOGENESIS OF RA SINCE THEY ATTRACT AND ACTIVATE IMMUNE CELLS AND PRODUCE MATRIX DEGRADING ENZYMES. MOST NOTABLY SYNOVIAL FIBROBLASTS FROM PATIENTS WITH RA ARE STABLY ACTIVATED AND PRODUCE HIGH LEVELS OF DISEASE-PROMOTING MOLECULES WITHOUT FURTHER STIMULATION BY IMMUNE CELLS. ACCUMULATING DATA SUGGEST THAT EPIGENETIC CHANGES IN STROMAL CELL POPULATIONS MIGHT BE CRUCIALLY INVOLVED IN THE PATHOLOGY OF RA AND OTHER CHRONIC INFLAMMATORY DISEASES. IN THE CURRENT REVIEW, WE DISCUSS THE MECHANISMS BY WHICH EPIGENETIC CHANGES MIGHT CAUSE THE STABLE ACTIVATION OF SYNOVIAL FIBROBLASTS IN RA AND HOW CHANGES IN THE EPIGENOME MIGHT ALTER IMMUNE FUNCTION AND INFLAMMATORY RESPONSE AND THEREBY PROMOTE THE DEVELOPMENT OF CHRONIC DISEASES. 2011 7 5739 30 SMOKING AND RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC INFLAMMATORY DISEASE CAUSED BY BOTH GENETIC AND ENVIRONMENTAL FACTORS. SMOKING HAS BEEN IMPLICATED AS ONE OF THE MOST IMPORTANT EXTRINSIC RISK FACTORS FOR ITS DEVELOPMENT AND SEVERITY. RECENT DEVELOPMENTS HAVE SHED LIGHT ON THE PATHOPHYSIOLOGY OF RA IN SMOKERS, INCLUDING OXIDATIVE STRESS, INFLAMMATION, AUTOANTIBODY FORMATION AND EPIGENETIC CHANGES. THE ASSOCIATION OF SMOKING AND THE DEVELOPMENT OF RA HAVE BEEN DEMONSTRATED THROUGH EPIDEMIOLOGIC STUDIES, AS WELL AS THROUGH IN VIVO AND ANIMAL MODELS OF RA. WITH INCREASED USE OF BIOLOGICAL AGENTS IN ADDITION TO STANDARD DISEASE-MODIFYING ANTIRHEUMATIC DRUGS (DMARDS), THERE HAS BEEN INTEREST IN HOW SMOKING AFFECTS DRUG RESPONSE IN RA TREATMENT. RECENT EVIDENCE SUGGESTS THE RESPONSE AND DRUG SURVIVAL IN PEOPLE TREATED WITH ANTI-TUMOUR NECROSIS FACTOR (ANTI-TNF) THERAPY IS POORER IN HEAVY SMOKERS, AND POSSIBLE IMMUNOLOGICAL MECHANISMS FOR THIS EFFECT ARE PRESENTED IN THE CURRENT PAPER. 2014 8 4657 30 NEW ADVANCES OF DNA METHYLATION AND HISTONE MODIFICATIONS IN RHEUMATOID ARTHRITIS, WITH SPECIAL EMPHASIS ON MECP2. EPIGENETICS IS A STEADILY GROWING RESEARCH AREA IN MANY HUMAN DISEASES, ESPECIALLY IN AUTOIMMUNE DISEASES SUCH AS RHEUMATOID ARTHRITIS (RA). RA IS AN AUTOIMMUNE DISEASE WITH UNCLEAR ETIOLOGY CHARACTERIZED BY CHRONIC INFLAMMATION AND JOINT DESTRUCTION AND FIBROBLAST-LIKE SYNOVIOCYTES (FLS) DISPLAY A CRUCIAL ROLE IN THE PATHOGENESIS OF RA. EVEN THOUGH THE ETIOLOGY IS NOT YET FULLY UNDERSTOOD, RA IS GENERALLY CONSIDERED TO BE CAUSED BY A COMBINATION OF EPIGENETIC MODIFICATION, DEREGULATED IMMUNOMODULATION, AND ENVIRONMENTAL FACTORS. EPIGENETIC MODIFICATIONS, INCLUDING DNA METHYLATION AND POST-TRANSLATIONAL HISTONE MODIFICATIONS, SUCH AS HISTONE METHYLATION AND HISTONE (DE)ACETYLATION ARE IDENTIFIED AS REGULATORY MECHANISMS IN CONTROLLING AGGRESSIVE FLS ACTIVATION IN PATIENTS AND ANIMAL MODELS. IN THE LAST 3YEARS, THE FIELD OF EPIGENETICS IN RA HAS IMPRESSIVELY INCREASED. METHYL-CPG-BINDING PROTEIN 2 (MECP2) IS FIRST IDENTIFIED AS A TRANSCRIPTIONAL REPRESSOR THAT INHIBITS GENE EXPRESSION THROUGH THE INTERPRETATION OF TWO EPIGENETIC MARKERS, DNA METHYLATION AND HISTONE MODIFICATION. THE COOPERATIVE ACTION AMONG MECP2, DNA METHYLATION AND HISTONE MODIFICATIONS INDICATES THAT MECP2 SHOULD PARTICIPATE IN THE PATHOGENESIS OF RA THROUGH SILENCE OF CERTAIN GENE TRANSCRIPTION. IN THIS REVIEW, WE CONSIDER THE ROLE OF DNA METHYLATION AND HISTONE MODIFICATIONS IN THE DEVELOPMENT OF RA, WITH A SPECIAL FOCUS ON INCREASED MECP2 EXPRESSION IN RA ANIMAL MODELS. 2013 9 4842 33 ONE YEAR IN REVIEW 2017: PATHOGENESIS OF RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC INFLAMMATORY AUTOIMMUNE DISEASE INFLUENCED BY BOTH GENETIC AND ENVIRONMENTAL FACTORS. IT HAS BEEN POSTULATED THAT A HIGH-RISK GENETIC BACKGROUND, IN COMBINATION WITH EPIGENETIC MARKS AND ENVIRONMENTAL EXPOSURES, LEADS TO A CASCADE OF EVENTS INDUCING SYNOVITIS AND CONSEQUENT DESTRUCTIVE ARTHRITIS. THE CLINICAL PICTURE OF JOINT INVOLVEMENT IN RA IS THE RESULT OF CHRONIC INFLAMMATION OF THE SYNOVIUM, CHARACTERISED BY INTERACTIONS OF RESIDENT CELLS SUCH AS FIBROBLAST-LIKE SYNOVIOCYTES (FLS) WITH CELLS OF THE INNATE (E.G. MACROPHAGES, DENDRITIC CELLS, MAST CELLS AND NK CELLS, NEUTROPHILS) AND ADAPTIVE IMMUNE SYSTEM (E.G. B AND T LYMPHOCYTES). CURRENTLY, OUR UNDERSTANDING OF THE ROLE OF INNATE AND ADAPTIVE IMMUNITY IN THE PATHOGENESIS OF RA IS EXPANDING. THE CONCEPT OF HOW IMMUNE RESPONSES CONTRIBUTE TO THE DISEASE HAS DRAMATICALLY EVOLVED OVER THE LAST 50 YEARS. SHEDDING SOME LIGHT ON THE DIFFERENT ASPECTS OF RA PATHOGENESIS WILL HELP TO IDENTIFY NEW TARGETS FOR THE DEVELOPMENT OF DISEASE-MODIFYING THERAPIES. THUS, IN THIS REVIEW WE REPORT NEW INSIGHTS IN RA PATHOGENESIS, RESULTING FROM A LITERATURE RESEARCH DATE PUBLISHED IN THE LAST YEAR. 2017 10 6178 29 THE HISTONE MODIFICATION CODE IN THE PATHOGENESIS OF AUTOIMMUNE DISEASES. AUTOIMMUNE DISEASES ARE CHRONIC INFLAMMATORY DISORDERS CAUSED BY A LOSS OF SELF-TOLERANCE, WHICH IS CHARACTERIZED BY THE APPEARANCE OF AUTOANTIBODIES AND/OR AUTOREACTIVE LYMPHOCYTES AND THE IMPAIRED SUPPRESSIVE FUNCTION OF REGULATORY T CELLS. THE PATHOGENESIS OF AUTOIMMUNE DISEASES IS EXTREMELY COMPLEX AND REMAINS LARGELY UNKNOWN. RECENT ADVANCES INDICATE THAT ENVIRONMENTAL FACTORS TRIGGER AUTOIMMUNE DISEASES IN GENETICALLY PREDISPOSED INDIVIDUALS. IN ADDITION, ACCUMULATING RESULTS HAVE INDICATED A POTENTIAL ROLE OF EPIGENETIC MECHANISMS, SUCH AS HISTONE MODIFICATIONS, IN THE DEVELOPMENT OF AUTOIMMUNE DISEASES. HISTONE MODIFICATIONS REGULATE THE CHROMATIN STATES AND GENE TRANSCRIPTION WITHOUT ANY CHANGE IN THE DNA SEQUENCE, POSSIBLY RESULTING IN PHENOTYPE ALTERATION IN SEVERAL DIFFERENT CELL TYPES. IN THIS PAPER, WE DISCUSS THE SIGNIFICANT ROLES OF HISTONE MODIFICATIONS INVOLVED IN THE PATHOGENESIS OF AUTOIMMUNE DISEASES, INCLUDING RHEUMATOID ARTHRITIS, SYSTEMIC LUPUS ERYTHEMATOSUS, SYSTEMIC SCLEROSIS, PRIMARY BILIARY CIRRHOSIS, AND TYPE 1 DIABETES. 2017 11 2550 32 EPIGENETICS IN OSTEOARTHRITIS: POTENTIAL OF HDAC INHIBITORS AS THERAPEUTICS. OSTEOARTHRITIS (OA) IS THE MOST COMMON JOINT DISEASE AND THE LEADING CAUSE OF CHRONIC DISABILITY IN MIDDLE-AGED AND OLDER POPULATIONS WORLDWIDE. THE DEVELOPMENT OF DISEASE MODIFYING THERAPY FOR OA IS IN ITS INFANCY LARGELY BECAUSE THE REGULATORY MECHANISMS FOR THE MOLECULAR EFFECTORS OF OA PATHOGENESIS ARE POORLY UNDERSTOOD. RECENT STUDIES IDENTIFIED EPIGENETIC EVENTS AS A CRITICAL REGULATOR OF MOLECULAR PLAYERS INVOLVED IN THE INDUCTION AND DEVELOPMENT OF OA. EPIGENETIC MECHANISMS INCLUDE DNA METHYLATION, NON-CODING RNA AND HISTONE MODIFICATIONS. THE AIM OF THIS REVIEW IS TO BRIEFLY HIGHLIGHT THE RECENT ADVANCES IN THE EPIGENETICS OF CARTILAGE AND POTENTIAL OF HDACS (HISTONE DEACETYLASES) INHIBITORS IN THE THERAPEUTIC MANAGEMENT OF OA. WE SUMMARIZE THE RECENT STUDIES UTILIZING HDAC INHIBITORS AS POTENTIAL THERAPEUTICS FOR INHIBITING DISEASE PROGRESSION AND PREVENTING THE CARTILAGE DESTRUCTION IN OA. HDACS CONTROL NORMAL CARTILAGE DEVELOPMENT AND HOMEOSTASIS AND UNDERSTANDING THE IMPACT OF HDACS INHIBITORS ON THE DISEASE PATHOGENESIS IS OF INTEREST BECAUSE OF ITS IMPORTANCE IN AFFECTING OVERALL CARTILAGE HEALTH AND HOMEOSTASIS. THESE FINDINGS ALSO SHED NEW LIGHT ON CARTILAGE DISEASE PATHOPHYSIOLOGY AND PROVIDE SUBSTANTIAL EVIDENCE THAT HDACS MAY BE POTENTIAL NOVEL THERAPEUTIC TARGETS IN OA. 2018 12 1136 36 COMPREHENSIVE OVERVIEW OF MICRORNA FUNCTION IN RHEUMATOID ARTHRITIS. MICRORNAS (MIRNAS), A CLASS OF ENDOGENOUS SINGLE-STRANDED SHORT NONCODING RNAS, HAVE EMERGED AS VITAL EPIGENETIC REGULATORS OF BOTH PATHOLOGICAL AND PHYSIOLOGICAL PROCESSES IN ANIMALS. THEY DIRECT FUNDAMENTAL CELLULAR PATHWAYS AND PROCESSES BY FINE-TUNING THE EXPRESSION OF MULTIPLE GENES AT THE POSTTRANSCRIPTIONAL LEVEL. GROWING EVIDENCE SUGGESTS THAT MIRNAS ARE IMPLICATED IN THE ONSET AND DEVELOPMENT OF RHEUMATOID ARTHRITIS (RA). RA IS A CHRONIC INFLAMMATORY DISEASE THAT MAINLY AFFECTS SYNOVIAL JOINTS. THIS COMMON AUTOIMMUNE DISORDER IS CHARACTERIZED BY A COMPLEX AND MULTIFACETED PATHOGENESIS, AND ITS MORBIDITY, DISABILITY AND MORTALITY RATES REMAIN CONSISTENTLY HIGH. MORE IN-DEPTH INSIGHTS INTO THE UNDERLYING MECHANISMS OF RA ARE REQUIRED TO ADDRESS UNMET CLINICAL NEEDS AND OPTIMIZE TREATMENT. HEREIN, WE COMPREHENSIVELY REVIEW THE DEREGULATED MIRNAS AND IMPAIRED CELLULAR FUNCTIONS IN RA TO SHED LIGHT ON SEVERAL ASPECTS OF RA PATHOGENESIS, WITH A FOCUS ON EXCESSIVE INFLAMMATION, SYNOVIAL HYPERPLASIA AND PROGRESSIVE JOINT DAMAGE. THIS REVIEW ALSO PROVIDES PROMISING TARGETS FOR INNOVATIVE THERAPIES OF RA. IN ADDITION, WE DISCUSS THE REGULATORY ROLES AND CLINICAL POTENTIAL OF EXTRACELLULAR MIRNAS IN RA, HIGHLIGHTING THEIR PROSPECTIVE APPLICATIONS AS DIAGNOSTIC AND PREDICTIVE BIOMARKERS. 2023 13 2054 32 EPIGENETIC CONTRIBUTIONS IN THE DEVELOPMENT OF RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS (RA) IS AN AUTOIMMUNE DISEASE, CHARACTERIZED BY CHRONIC INFLAMMATION OF THE JOINTS WITH SEVERE PAIN AND SWELLING, JOINT DAMAGE AND DISABILITY, WHICH LEADS TO JOINT DESTRUCTION AND LOSS OF FUNCTION. DESPITE EXTENSIVE RESEARCH EFFORTS, THE UNDERLYING CAUSE FOR RA IS STILL UNKNOWN AND CURRENT THERAPIES ARE MORE OR LESS EFFECTIVE IN CONTROLLING SYMPTOMS BUT STILL FAIL TO CURE THE DISEASE. IN RECENT YEARS, EPIGENETIC MODIFICATIONS WERE FOUND TO STRONGLY CONTRIBUTE TO THE DEVELOPMENT OF RA BY AFFECTING DIVERSE ASPECTS OF THE DISEASE AND MODIFYING GENE EXPRESSION LEVELS AND BEHAVIOR OF SEVERAL CELL TYPES, FIRST AND FOREMOST JOINT RESIDENT SYNOVIAL FIBROBLASTS (SF). RASF ARE THE MOST COMMON CELL TYPE AT THE SITE OF INVASION. OWING TO THEIR AGGRESSIVE, INTRINSICALLY ACTIVATED PHENOTYPE, RASF ARE ACTIVE CONTRIBUTORS IN JOINT DAMAGE. RASF ARE CHARACTERIZED BY THEIR ABILITY TO SECRETE CYTOKINES, CHEMOKINES AND JOINT-DAMAGING ENZYMES. FURTHERMORE, THESE CELLS ARE RESISTANT TO APOPTOSIS, LEADING TO HYPERPLASIA OF THE SYNOVIUM. IN ADDITION, RASF HAVE INVASIVE AND MIGRATORY PROPERTIES THAT COULD LEAD TO SPREADING OF THE DISEASE TO UNAFFECTED JOINTS. EPIGENETIC MODIFICATIONS, INCLUDING DNA METHYLATION AND POST-TRANSLATIONAL HISTONE MODIFICATIONS, SUCH AS HISTONE (DE)ACETYLATION, HISTONE METHYLATION AND HISTONE SUMOYLATION WERE IDENTIFIED AS REGULATORY MECHANISMS IN CONTROLLING AGGRESSIVE CELL ACTIVATION IN VITRO AND IN DISEASE OUTCOME IN ANIMAL MODELS IN VIVO. IN THE LAST 5 YEARS, THE FIELD OF EPIGENETICS IN RA HAS IMPRESSIVELY INCREASED. IN THIS REVIEW WE CONSIDER THE ROLE OF DIVERSE EPIGENETIC MODIFICATIONS IN THE DEVELOPMENT OF RA, WITH A SPECIAL FOCUS ON EPIGENETIC MODIFICATIONS IN RASF. 2012 14 1565 32 DNA METHYLATION OF T LYMPHOCYTES AS A THERAPEUTIC TARGET: IMPLICATIONS FOR RHEUMATOID ARTHRITIS ETIOLOGY. RHEUMATOID ARTHRITIS (RA) IS AN AUTOIMMUNE DISEASE THAT CAN CAUSE JOINT DAMAGE AND DISABILITY. EPIGENETIC VARIATION, ESPECIALLY DNA METHYLATION, HAS BEEN SHOWN TO BE INVOLVED IN ALMOST ALL THE STAGES OF THE PATHOLOGY OF RA, FROM AUTOANTIBODY PRODUCTION TO VARIOUS SELF-EFFECTOR T CELLS AND THE DEFECTS OF PROTECTIVE T CELLS THAT CAN LEAD TO CHRONIC INFLAMMATION AND EROSION OF BONES AND JOINTS. GIVEN THE CRITICAL ROLE OF T CELLS IN THE PATHOLOGY OF RA, THE REGULATORY FUNCTIONS OF DNA METHYLATION IN T CELL BIOLOGY REMAIN UNCLEAR. IN THIS REVIEW, WE ELABORATE ON THE RELATIONSHIP BETWEEN RA PATHOGENESIS AND DNA METHYLATION IN THE CONTEXT OF DIFFERENT T CELL POPULATIONS. WE SUMMARIZE THE RELEVANT METHYLATION EVENTS IN T CELL DEVELOPMENT, DIFFERENTIATION, AND T CELL-RELATED GENES IN DISEASE PREDICTION AND DRUG EFFICACY. UNDERSTANDING THE EPIGENETIC REGULATION OF T CELLS HAS THE POTENTIAL TO PROFOUNDLY TRANSLATE PRECLINICAL RESULTS INTO CLINICAL PRACTICE AND PROVIDE A FRAMEWORK FOR THE DEVELOPMENT OF NOVEL, INDIVIDUALIZED RA THERAPEUTICS. 2022 15 4380 34 MITOCHONDRIAL DYSFUNCTION AND OXIDATIVE STRESS IN RHEUMATOID ARTHRITIS. CONTROL OF EXCESSIVE MITOCHONDRIAL OXIDATIVE STRESS COULD PROVIDE NEW TARGETS FOR BOTH PREVENTIVE AND THERAPEUTIC INTERVENTIONS IN THE TREATMENT OF CHRONIC INFLAMMATION OR ANY PATHOLOGY THAT DEVELOPS UNDER AN INFLAMMATORY SCENARIO, SUCH AS RHEUMATOID ARTHRITIS (RA). INCREASING EVIDENCE HAS DEMONSTRATED THE ROLE OF MITOCHONDRIAL ALTERATIONS IN AUTOIMMUNE DISEASES MAINLY DUE TO THE INTERPLAY BETWEEN METABOLISM AND INNATE IMMUNITY, BUT ALSO IN THE MODULATION OF INFLAMMATORY RESPONSE OF RESIDENT CELLS, SUCH AS SYNOVIOCYTES. THUS, MITOCHONDRIAL DYSFUNCTION DERIVED FROM SEVERAL DANGER SIGNALS COULD ACTIVATE TRICARBOXYLIC ACID (TCA) DISRUPTION, THEREBY FAVORING A VICIOUS CYCLE OF OXIDATIVE/MITOCHONDRIAL STRESS. MITOCHONDRIAL DYSFUNCTION CAN ACT THROUGH MODULATING INNATE IMMUNITY VIA REDOX-SENSITIVE INFLAMMATORY PATHWAYS OR DIRECT ACTIVATION OF THE INFLAMMASOME. BESIDES, MITOCHONDRIA ALSO HAVE A CENTRAL ROLE IN REGULATING CELL DEATH, WHICH IS DEEPLY ALTERED IN RA. ADDITIONALLY, MULTIPLE EVIDENCE SUGGESTS THAT PATHOLOGICAL PROCESSES IN RA CAN BE SHAPED BY EPIGENETIC MECHANISMS AND THAT IN TURN, MITOCHONDRIA ARE INVOLVED IN EPIGENETIC REGULATION. FINALLY, WE WILL DISCUSS ABOUT THE INVOLVEMENT OF SOME DIETARY COMPONENTS IN THE ONSET AND PROGRESSION OF RA. 2022 16 2294 37 EPIGENETIC REGULATION IN THE PATHOGENESIS OF SJOGREN SYNDROME AND RHEUMATOID ARTHRITIS. AUTOIMMUNE RHEUMATIC DISEASES, SUCH AS SJOGREN SYNDROME (SS) AND RHEUMATOID ARTHRITIS (RA), ARE CHARACTERIZED BY CHRONIC INFLAMMATION AND AUTOIMMUNITY, WHICH CAUSE JOINT TISSUE DAMAGE AND DESTRUCTION BY TRIGGERING REDUCED MOBILITY AND DEBILITATION IN PATIENTS WITH THESE DISEASES. INITIATION AND MAINTENANCE OF CHRONIC INFLAMMATORY STAGES ACCOUNT FOR SEVERAL MECHANISMS THAT INVOLVE IMMUNE CELLS AS KEY PLAYERS AND THE INTERACTION OF THE IMMUNE CELLS WITH OTHER TISSUES. INDEED, THE OVERLAPPING OF CERTAIN CLINICAL AND SEROLOGIC MANIFESTATIONS BETWEEN SS AND RA MAY INDICATE THAT NUMEROUS IMMUNOLOGIC-RELATED MECHANISMS ARE INVOLVED IN THE PHYSIOPATHOLOGY OF BOTH THESE DISEASES. IT IS WIDELY ACCEPTED THAT EPIGENETIC PATHWAYS PLAY AN ESSENTIAL ROLE IN THE DEVELOPMENT AND FUNCTION OF THE IMMUNE SYSTEM. ALTHOUGH MANY PUBLISHED STUDIES HAVE ATTEMPTED TO ELUCIDATE THE RELATION BETWEEN EPIGENETIC MODIFICATIONS (E.G. DNA METHYLATION, HISTONE POST-TRANSLATIONAL MODIFICATIONS, MIRNAS) AND AUTOIMMUNE DISORDERS, THE CONTRIBUTION OF EPIGENETIC REGULATION TO THE PATHOGENESIS OF SS AND RA IS AT PRESENT POORLY UNDERSTOOD. THIS REVIEW ATTEMPTS TO SHED LIGHT FROM A CRITICAL POINT OF VIEW ON THE IDENTIFICATION OF THE MOST RELEVANT EPIGENETIC MECHANISMS RELATED TO RA AND SS BY EXPLAINING INTRICATE REGULATORY PROCESSES AND PHENOTYPIC FEATURES OF BOTH AUTOIMMUNE DISEASES. MOREOVER, WE POINT OUT SOME EPIGENETIC MARKERS WHICH CAN BE USED TO MONITOR THE INFLAMMATION STATUS AND THE DYSREGULATED IMMUNITY IN SS AND RA. FINALLY, WE DISCUSS THE INCONVENIENCE OF USING EPIGENETIC DATA OBTAINED FROM BULK IMMUNE CELL POPULATIONS INSTEAD SPECIFIC IMMUNE CELL SUBPOPULATIONS. 2019 17 5561 33 ROLE OF HISTONE DEACETYLASES IN MONOCYTE FUNCTION IN HEALTH AND CHRONIC INFLAMMATORY DISEASES. HISTONE DEACETYLASES (HDACS) ARE A FAMILY OF 18 MEMBERS THAT PARTICIPATE IN THE EPIGENETIC REGULATION OF GENE EXPRESSION. IN ADDITION TO HISTONES, SOME HDACS ALSO DEACETYLATE TRANSCRIPTION FACTORS AND SPECIFIC CYTOPLASMIC PROTEINS.MONOCYTES, AS PART OF THE INNATE IMMUNE SYSTEM, MAINTAIN TISSUE HOMEOSTASIS AND HELP FIGHT INFECTIONS AND CANCER. IN THESE CELLS, HDACS ARE INVOLVED IN MULTIPLE PROCESSES INCLUDING PROLIFERATION, MIGRATION, DIFFERENTIATION, INFLAMMATORY RESPONSE, INFECTIONS, AND TUMORIGENESIS. HERE, A SYSTEMATIC DESCRIPTION OF THE ROLE THAT MOST HDACS PLAY IN THESE FUNCTIONS IS REVIEWED. SPECIFICALLY, SOME HDACS INDUCE A PRO-INFLAMMATORY RESPONSE AND PLAY MAJOR ROLES IN HOST DEFENSE. CONVERSELY, OTHER HDACS REPROGRAM MONOCYTES AND MACROPHAGES TOWARDS AN IMMUNOSUPPRESSIVE PHENOTYPE. THE RIGHT BALANCE BETWEEN BOTH TYPES HELPS MONOCYTES TO RESPOND CORRECTLY TO THE DIFFERENT PHYSIOLOGICAL/PATHOLOGICAL STIMULI. HOWEVER, ABERRANT EXPRESSIONS OR ACTIVITIES OF SPECIFIC HDACS ARE ASSOCIATED WITH AUTOIMMUNE DISEASES ALONG WITH OTHER CHRONIC INFLAMMATORY DISEASES, INFECTIONS, OR CANCER.THIS PAPER CRITICALLY REVIEWS THE INTERESTING AND EXTENSIVE KNOWLEDGE REGARDING THE ROLE OF SOME HDACS IN THESE PATHOLOGIES. IT ALSO SHOWS THAT AS YET, VERY LITTLE PROGRESS HAS BEEN MADE TOWARD THE GOAL OF FINDING EFFECTIVE HDAC-TARGETED THERAPIES. HOWEVER, GIVEN THEIR OBVIOUS POTENTIAL, WE CONCLUDE THAT IT IS WORTH THE EFFORT TO DEVELOP MONOCYTE-SPECIFIC DRUGS THAT SELECTIVELY TARGET HDAC SUBTYPES WITH THE AIM OF FINDING EFFECTIVE TREATMENTS FOR DISEASES IN WHICH OUR INNATE IMMUNE SYSTEM IS INVOLVED. 2021 18 4679 31 NEW MOLECULAR TARGETS FOR THE TREATMENT OF OSTEOARTHRITIS. OSTEOARTHRITIS (OA) IS A CHRONIC DEGENERATIVE JOINT DISORDER CHARACTERIZED BY DESTRUCTION OF THE ARTICULAR CARTILAGE, SUBCHONDRAL BONE ALTERATIONS AND SYNOVITIS. CURRENT TREATMENTS ARE FOCUSED ON SYMPTOMATIC RELIEF BUT THEY LACK EFFICACY TO CONTROL THE PROGRESSION OF THIS DISEASE WHICH IS A LEADING CAUSE OF DISABILITY. THEREFORE, THE DEVELOPMENT OF EFFECTIVE DISEASE-MODIFYING DRUGS IS URGENTLY NEEDED. DIFFERENT INITIATIVES ARE IN PROGRESS TO DEFINE THE MOLECULAR MECHANISMS INVOLVED IN THE INITIATION AND PROGRESSION OF OA. THESE STUDIES SUPPORT THE THERAPEUTIC POTENTIAL OF PATHWAYS RELEVANT IN JOINT METABOLISM SUCH AS WNT/BETA-CATENIN, DISCOIDIN DOMAIN RECEPTOR 2 OR PROTEINASE-ACTIVATED RECEPTOR 2. THE DYSREGULATION IN CARTILAGE CATABOLISM AND SUBCHONDRAL BONE REMODELING COULD BE IMPROVED BY SELECTIVE INHIBITORS OF MATRIX METALLOPROTEINASES, AGGRECANASES AND OTHER PROTEASES. ANOTHER APPROACH WOULD FAVOR THE ACTIVITY OF ANABOLIC PROCESSES BY USING GROWTH FACTORS OR REGULATORY MOLECULES. RECENT STUDIES HAVE ALSO REVEALED THE ROLE OF OXIDATIVE STRESS AND SYNOVITIS IN THE PROGRESSION OF THIS DISEASE, SUPPORTING THE DEVELOPMENT OF A NUMBER OF INHIBITORY STRATEGIES. NOVEL TARGETS IN OA ARE REPRESENTED BY GENES INVOLVED IN OA PATHOPHYSIOLOGY DISCOVERED USING GENE NETWORK, EPIGENETIC AND MICRORNA APPROACHES. FURTHER INSIGHTS INTO THE MOLECULAR MECHANISMS INVOLVED IN OA INITIATION AND PROGRESSION MAY LEAD TO THE DEVELOPMENT OF NEW THERAPIES ABLE TO CONTROL JOINT DESTRUCTION AND REPAIR. 2010 19 5932 31 TARGETING EPIGENETIC REGULATORS FOR INFLAMMATION: MECHANISMS AND INTERVENTION THERAPY. EMERGING EVIDENCE INDICATES THAT RESOLUTION OF INFLAMMATION IS A CRITICAL AND DYNAMIC ENDOGENOUS PROCESS FOR HOST TISSUES DEFENDING AGAINST EXTERNAL INVASIVE PATHOGENS OR INTERNAL TISSUE INJURY. IT HAS LONG BEEN KNOWN THAT AUTOIMMUNE DISEASES AND CHRONIC INFLAMMATORY DISORDERS ARE CHARACTERIZED BY DYSREGULATED IMMUNE RESPONSES, LEADING TO EXCESSIVE AND UNCONTROL TISSUE INFLAMMATION. THE DYSREGULATION OF EPIGENETIC ALTERATIONS INCLUDING DNA METHYLATION, POSTTRANSLATIONAL MODIFICATIONS TO HISTONE PROTEINS, AND NONCODING RNA EXPRESSION HAS BEEN IMPLICATED IN A HOST OF INFLAMMATORY DISORDERS AND THE IMMUNE SYSTEM. THE INFLAMMATORY RESPONSE IS CONSIDERED AS A CRITICAL TRIGGER OF EPIGENETIC ALTERATIONS THAT IN TURN INTERCEDE INFLAMMATORY ACTIONS. THUS, UNDERSTANDING THE MOLECULAR MECHANISM THAT DICTATES THE OUTCOME OF TARGETING EPIGENETIC REGULATORS FOR INFLAMMATORY DISEASE IS REQUIRED FOR INFLAMMATION RESOLUTION. IN THIS ARTICLE, WE ELUCIDATE THE CRITICAL ROLE OF THE NUCLEAR FACTOR-KAPPAB SIGNALING PATHWAY, JAK/STAT SIGNALING PATHWAY, AND THE NLRP3 INFLAMMASOME IN CHRONIC INFLAMMATORY DISEASES. AND WE FORMULATE THE RELATIONSHIP BETWEEN INFLAMMATION, CORONAVIRUS DISEASE 2019, AND HUMAN CANCERS. ADDITIONALLY, WE REVIEW THE MECHANISM OF EPIGENETIC MODIFICATIONS INVOLVED IN INFLAMMATION AND INNATE IMMUNE CELLS. ALL THAT MATTERS IS THAT WE PROPOSE AND DISCUSS THE REJUVENATION POTENTIAL OF INTERVENTIONS THAT TARGET EPIGENETIC REGULATORS AND REGULATORY MECHANISMS FOR CHRONIC INFLAMMATION-ASSOCIATED DISEASES TO IMPROVE THERAPEUTIC OUTCOMES. 2022 20 5410 32 REGULATION OF ADAPTIVE IMMUNE CELLS BY SIRTUINS. IT IS NOW WELL-ESTABLISHED THAT THE PATHWAYS THAT CONTROL LYMPHOCYTE METABOLISM AND FUNCTION ARE INTIMATELY LINKED, AND CHANGES IN LYMPHOCYTE METABOLISM CAN INFLUENCE AND DIRECT CELLULAR FUNCTION. INTERESTINGLY, A NUMBER OF RECENT ADVANCES INDICATE THAT LYMPHOCYTE IDENTITY AND METABOLISM IS PARTIALLY CONTROLLED VIA EPIGENETIC REGULATION. EPIGENETIC MECHANISMS, SUCH AS CHANGES IN DNA METHYLATION OR HISTONE ACETYLATION, HAVE BEEN FOUND TO ALTER IMMUNE FUNCTION AND PLAY A ROLE IN NUMEROUS CHRONIC DISEASE STATES. THERE ARE SEVERAL ENZYMES THAT CAN MEDIATE EPIGENETIC CHANGES; OF PARTICULAR INTEREST ARE SIRTUINS, PROTEIN DEACETYLASES THAT MEDIATE ADAPTIVE RESPONSES TO A VARIETY OF STRESSES (INCLUDING CALORIE RESTRICTION AND METABOLIC STRESS) AND ARE NOW UNDERSTOOD TO PLAY A SIGNIFICANT ROLE IN IMMUNITY. THIS REVIEW WILL FOCUS ON RECENT ADVANCES IN THE UNDERSTANDING OF HOW SIRTUINS AFFECT THE ADAPTIVE IMMUNE SYSTEM. THESE PATHWAYS ARE OF SIGNIFICANT INTEREST AS THERAPEUTIC TARGETS FOR THE TREATMENT OF AUTOIMMUNITY, CANCER, AND TRANSPLANT TOLERANCE. 2019