1 6102 108 THE EMERGING ROLE OF FIBROBLAST-LIKE SYNOVIOCYTES-MEDIATED SYNOVITIS IN OSTEOARTHRITIS: AN UPDATE. OSTEOARTHRITIS (OA), THE MOST UBIQUITOUS DEGENERATIVE DISEASE AFFECTING THE ENTIRE JOINT, IS CHARACTERIZED BY CARTILAGE DEGRADATION AND SYNOVIAL INFLAMMATION. ALTHOUGH THE PATHOGENESIS OF OA REMAINS POORLY UNDERSTOOD, SYNOVIAL INFLAMMATION IS KNOWN TO PLAY AN IMPORTANT ROLE IN OA DEVELOPMENT. HOWEVER, STUDIES ON OA PATHOPHYSIOLOGY HAVE FOCUSED MORE ON CARTILAGE DEGENERATION AND OSTEOPHYTES, RATHER THAN ON THE INFLAMED AND THICKENED SYNOVIUM. FIBROBLAST-LIKE SYNOVIOCYTES (FLS) PRODUCE A SERIES OF PRO-INFLAMMATORY REGULATORS, SUCH AS INFLAMMATORY CYTOKINES, NITRIC OXIDE (NO) AND PROSTAGLANDIN E(2) (PGE(2) ). THESE REGULATORS ARE POSITIVELY ASSOCIATED WITH THE CLINICAL SYMPTOMS OF OA, SUCH AS INFLAMMATORY PAIN, JOINT SWELLING AND DISEASE DEVELOPMENT. A BETTER UNDERSTANDING OF THE INFLAMMATORY IMMUNE RESPONSE IN OA-FLS COULD PROVIDE A NOVEL APPROACH TO COMPREHENSIVE TREATMENT STRATEGIES FOR OA. HERE, WE HAVE SUMMARIZED RECENTLY PUBLISHED LITERATURES REFERRING TO EPIGENETIC MODIFICATIONS, ACTIVATED SIGNALLING PATHWAYS AND INFLAMMATION-ASSOCIATED FACTORS THAT ARE INVOLVED IN OA-FLS-MEDIATED INFLAMMATION. IN ADDITION, THE CURRENT RELATED CLINICAL TRIALS AND FUTURE PERSPECTIVES WERE ALSO SUMMARIZED. 2020 2 783 35 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 39 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 4416 32 MOLECULAR AND CELLULAR PATHWAYS CONTRIBUTING TO JOINT DAMAGE IN RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS IS A CHRONIC AUTOIMMUNE SYNDROME ASSOCIATED WITH SEVERAL GENETIC, EPIGENETIC, AND ENVIRONMENTAL FACTORS AFFECTING THE ARTICULAR JOINTS CONTRIBUTING TO CARTILAGE AND BONE DAMAGE. ALTHOUGH ETIOLOGY OF THIS DISEASE IS NOT CLEAR, SEVERAL IMMUNE PATHWAYS, INVOLVING IMMUNE (T CELLS, B CELLS, DENDRITIC CELLS, MACROPHAGES, AND NEUTROPHILS) AND NONIMMUNE (FIBROBLASTS AND CHONDROCYTES) CELLS, PARTICIPATE IN THE SECRETION OF MANY PROINFLAMMATORY CYTOKINES, CHEMOKINES, PROTEASES (MMPS, ADAMTS), AND OTHER MATRIX LYSING ENZYMES THAT COULD DISTURB THE IMMUNE BALANCE LEADING TO CARTILAGE AND BONE DAMAGE. THE PRESENCE OF AUTOANTIBODIES PRECEDING THE CLINICAL ONSET OF ARTHRITIS AND THE INDUCTION OF BONE EROSION EARLY IN THE DISEASE COURSE CLEARLY SUGGEST THAT INITIATION EVENTS DAMAGING THE CARTILAGE AND BONE START VERY EARLY DURING THE AUTOIMMUNE PHASE OF THE ARTHRITIS DEVELOPMENT. DURING THIS PROCESS, SEVERAL SIGNALING MOLECULES (RANKL-RANK, NF-KAPPAB, MAPK, NFATC1, AND SRC KINASE) ARE ACTIVATED IN THE OSTEOCLASTS, CELLS RESPONSIBLE FOR BONE RESORPTION. HENCE, COMPREHENSIVE KNOWLEDGE ON PATHOGENESIS IS A PREREQUISITE FOR PREVENTION AND DEVELOPMENT OF TARGETED CLINICAL TREATMENT FOR RA PATIENTS THAT CAN RESTORE THE IMMUNE BALANCE IMPROVING CLINICAL THERAPY. 2020 5 2221 28 EPIGENETIC MODIFICATIONS IN RHEUMATOID ARTHRITIS, A REVIEW. RHEUMATOID ARTHRITIS IS AN AUTOIMMUNE DISEASE CHARACTERIZED BY CHRONIC JOINT INFLAMMATION AND PROGRESSIVE DESTRUCTION OF CARTILAGE AND BONE WHICH LEADS TO ULTIMATELY LOSS OF FUNCTION AND PAIN. ACTIVATED SYNOVIAL FIBROBLASTS ARE KEY EFFECTOR CELLS IN THE PATHOGENESIS OF RHEUMATOID ARTHRITIS. IN THE RECENT YEARS, EPIGENETIC CHANGES INCLUDING DNA METHYLATION, HISTONE ACETYLATION AND OTHER HISTONE MODIFICATIONS WERE IDENTIFIED THAT ARE ASSOCIATED WITH AN INTRINSIC ACTIVATION AND THE AGGRESSIVE PHENOTYPE OF THESE CELLS. SO FAR, NO THERAPIES TARGETING RHEUMATOID ARTHRITIS SYNOVIAL FIBROBLASTS EXIST. THIS REVIEW COMPRISES RECENT RESEARCH EFFORTS THAT PROPOSE EPIGENETIC MECHANISMS BEHIND THE ACTIVATION OF RHEUMATOID ARTHRITIS SYNOVIAL FIBROBLASTS AND OTHER CELL TYPES. 2013 6 3800 43 INTERPLAY OF INFLAMMATORY MEDIATORS WITH EPIGENETICS AND CARTILAGE MODIFICATIONS IN OSTEOARTHRITIS. OSTEOARTHRITIS (OA), A DEGENERATIVE DISEASE OF DIARTHRODIAL JOINTS, IS INFLUENCED BY MECHANICAL AND INFLAMMATORY FACTORS WITH AGING, OBESITY, CHRONIC INJURIES, AND SECONDARY DISEASES THOUGHT TO BE MAJOR FACTORS DRIVING THE PROCESS OF ARTICULAR CARTILAGE DEGENERATION. CHONDROCYTES, THE CELLULAR COMPONENT OF CARTILAGE, RESIDE IN AN AVASCULAR ENVIRONMENT AND NORMALLY HAVE LIMITED POTENTIAL TO REPLICATE. HOWEVER, EXTRINSIC FACTORS SUCH AS INJURY TO THE JOINT OR INTRINSIC ALTERATIONS TO THE CHONDROCYTES THEMSELVES CAN LEAD TO AN ALTERED PHENOTYPE AND DEVELOPMENT OF OA. SYNOVIAL INFLAMMATION IS ALSO A PIVOTAL ELEMENT OF THE OSTEOARTHRITIC, DEGENERATIVE PROCESS: INFLUX OF PRO-INFLAMMATORY CYTOKINES AND PRODUCTION OF MATRIX METALLOPROTEINASES ACCELERATE ADVANCED CELLULAR PROCESSES SUCH AS SYNOVITIS AND CARTILAGE DAMAGE. AS WELL AS A GENETIC INPUT, RECENT DATA HAVE HIGHLIGHTED EPIGENETIC FACTORS AS CONTRIBUTING TO DISEASE. STUDIES CONDUCTED OVER THE LAST DECADE HAVE FOCUSED ON THREE KEY ASPECTS IN OA; INFLAMMATION AND THE IMMUNE RESPONSE, GENOME-WIDE ASSOCIATION STUDIES THAT HAVE IDENTIFIED IMPORTANT GENES UNDERGOING EPIGENETIC MODIFICATIONS, AND FINALLY HOW CHONDROCYTES TRANSFORM IN THEIR FUNCTION DURING DEVELOPMENT AND DISEASE. DATA HIGHLIGHTED HERE HAVE IDENTIFIED CRITICAL INFLAMMATORY GENES INVOLVED IN OA AND HOW THESE FACTORS IMPACT CHONDROCYTE HYPERTROPHY IN THE DISEASE. THIS REVIEW ALSO ADDRESSES KEY INFLAMMATORY FACTORS IN SYNOVIAL INFLAMMATION, EPIGENETICS, AND CHONDROCYTE FATE, AND HOW AGENTS THAT INHIBIT EPIGENETIC MECHANISMS LIKE DNA METHYLATION AND HISTONE MODIFICATIONS COULD AID IN DEVELOPMENT OF LONG-TERM TREATMENT STRATEGIES FOR THE DISEASE. 2018 7 4842 36 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 8 2054 43 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 9 2309 37 EPIGENETIC REGULATION OF CHONDROCYTES AND SUBCHONDRAL BONE IN OSTEOARTHRITIS. THE AIM OF THIS REVIEW IS TO PROVIDE AN UPDATED REVIEW OF THE EPIGENETIC FACTORS INVOLVED IN THE ONSET AND DEVELOPMENT OF OSTEOARTHRITIS (OA). OA IS A PREVALENT DEGENERATIVE JOINT DISEASE CHARACTERIZED BY CHRONIC INFLAMMATION, ECTOPIC BONE FORMATION WITHIN THE JOINT, AND PHYSICAL AND PROTEOLYTIC CARTILAGE DEGRADATION WHICH RESULT IN CHRONIC PAIN AND LOSS OF MOBILITY. AT PRESENT, NO DISEASE-MODIFYING THERAPEUTICS EXIST FOR THE PREVENTION OR TREATMENT OF THE DISEASE. RESEARCH HAS IDENTIFIED SEVERAL OA RISK FACTORS INCLUDING MECHANICAL STRESSORS, PHYSICAL ACTIVITY, OBESITY, TRAUMATIC JOINT INJURY, GENETIC PREDISPOSITION, AND AGE. RECENTLY, THERE HAS BEEN INCREASED INTEREST IN IDENTIFYING EPIGENETIC FACTORS INVOLVED IN THE PATHOGENESIS OF OA. IN THIS REVIEW, WE DETAIL SEVERAL OF THESE EPIGENETIC MODIFICATIONS WITH KNOWN FUNCTIONS IN THE ONSET AND PROGRESSION OF THE DISEASE. WE ALSO REVIEW CURRENT THERAPEUTICS TARGETING ABERRANT EPIGENETIC REGULATION AS POTENTIAL OPTIONS FOR PREVENTIVE OR THERAPEUTIC TREATMENT. 2022 10 3699 28 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 11 2460 30 EPIGENETIC THERAPIES FOR OSTEOARTHRITIS. OSTEOARTHRITIS (OA) IS AN AGE-ASSOCIATED DISEASE CHARACTERIZED BY CHRONIC JOINT PAIN RESULTING FROM DEGRADATION OF ARTICULAR CARTILAGE, INFLAMMATION OF THE SYNOVIAL LINING, AND CHANGES TO THE SUBCHONDRAL BONE. DESPITE THE WIDE PREVALENCE, NO FDA-APPROVED DISEASE-MODIFYING DRUGS EXIST. RECENT EVIDENCE HAS DEMONSTRATED THAT EPIGENETIC DYSREGULATION OF MULTIPLE MOLECULAR PATHWAYS UNDERLIES OA PATHOGENESIS, PROVIDING A NEW MECHANISTIC AND THERAPEUTIC AXIS WITH THE ADVANTAGE OF TARGETING MULTIPLE DEREGULATED PATHWAYS SIMULTANEOUSLY. IN THIS REVIEW, WE FOCUS ON THE EPIGENETIC REGULATORS THAT HAVE BEEN IMPLICATED IN OA, THEIR INDIVIDUAL ROLES, AND POTENTIAL CROSSTALK. FINALLY, WE DISCUSS THE PHARMACOLOGICAL MOLECULES THAT CAN MODULATE THEIR ACTIVITIES AND DISCUSS THE POTENTIAL ADVANTAGES AND CHALLENGES ASSOCIATED WITH EPIGENOME-BASED THERAPEUTICS FOR OA. 2020 12 6328 21 THE ROLE OF CELL ORGANELLES IN RHEUMATOID ARTHRITIS WITH FOCUS ON EXOSOMES. AUTO-IMMUNE DISEASES INVOLVED AT LEAST 25% OF THE POPULATION IN WEALTHY COUNTRIES. SEVERAL FACTORS INCLUDING GENETIC, EPIGENETIC, AND ENVIRONMENTAL ELEMENTS ARE IMPLICATED IN DEVELOPMENT OF RHEUMATOID ARTHRITIS AS AN AUTOIMMUNE DISEASE. AUTOANTIBODIES CAUSE SYNOVIAL INFLAMMATION AND ARTHRITIS, IF LEFT UNTREATED OR BEING UNDER CONTINUAL EXTERNAL STIMULATION, COULD RESULT IN CHRONIC INFLAMMATION, JOINT INJURY, AND DISABILITY. T- AND B-CELLS, SIGNALING MOLECULES, PROINFLAMMATORY MEDIATORS, AND SYNOVIUM-SPECIFIC TARGETS ARE AMONG THE NEW THERAPEUTIC TARGETS. EXOSOMES COULD BE EMPLOYED AS THERAPEUTIC VECTORS IN THE TREATMENT OF AUTOIMMUNE DISEASES. HEREIN, THE ROLE OF CELL ORGANELLE PARTICULARLY EXOSOMES IN RHEUMATOID ARTHRITIS HAD DISCUSSED AND SOME THERAPEUTIC APPLICATIONS OF EXOSOME HIGHLIGHTED. 2021 13 1136 32 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 14 4679 40 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 15 1726 33 DYSREGULATION OF LNCRNAS IN RHEUMATOID ARTHRITIS: BIOMARKERS, PATHOGENESIS AND POTENTIAL THERAPEUTIC TARGETS. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC AUTOIMMUNE DISEASE OF UNKNOWN ETIOLOGY, MAINLY MANIFESTED BY PERSISTENT ABNORMAL PROLIFERATION OF FIBROBLAST-LIKE SYNOVIOCYTES (FLSS), INFLAMMATION, SYNOVIAL HYPERPLASIA AND CARTILAGE EROSION, ACCOMPANIED BY JOINT SWELLING AND JOINT DESTRUCTION. ABNORMAL EXPRESSION OR FUNCTION OF LONG NONCODING RNAS (LNCRNAS) ARE CLOSELY RELATED TO HUMAN DISEASES, INCLUDING CANCERS, MENTAL DISEASES, AUTOIMMUNE DISEASES AND OTHERS. THE ABNORMAL SEQUENCE AND SPATIAL STRUCTURE OF LNCRNAS, THE DISORDER EXPRESSION AND THE ABNORMAL INTERACTION WITH THE BINDING PROTEIN WILL LEAD TO THE CHANGE OF GENE EXPRESSION IN THE WAY OF EPIGENETIC MODIFICATION. INCREASING EVIDENCE DEMONSTRATED THAT LNCRNAS WERE INVOLVED IN THE ACTIVATION OF FLSS, WHICH PLAYED A KEY ROLE IN THE PATHOGENESIS OF RA. IN THIS REVIEW, THE RESEARCH PROGRESS OF LNCRNAS IN THE PATHOGENESIS OF RA WAS SYSTEMATICALLY SUMMARIZED, INCLUDING THE ROLE OF LNCRNAS IN THE DIAGNOSIS OF RA, THE REGULATORY MECHANISM OF LNCRNAS IN THE PATHOGENESIS OF RA, AND THE INTERVENTION ROLE OF LNCRNAS IN THE TREATMENT OF RA. FURTHERMORE, THE ACTIVATED SIGNAL PATHWAYS, THE ROLE OF DNA METHYLATION AND OTHER MECHANISM HAVE ALSO BEEN OVERVIEW IN THIS REVIEW. 2021 16 4412 32 MOLECULAR AND CELLULAR BASIS OF RHEUMATOID JOINT DESTRUCTION. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC INFLAMMATORY DISEASE ASSOCIATED WITH JOINT DESTRUCTION. SYNOVIAL FIBROBLASTS ARE KEY PLAYERS IN THIS PATHOLOGICAL PROCESS. THEY FAVORISE A PRO-INFLAMMATORY ENVIRONMENT IN THE SYNOVIAL TISSUE, INTERACT WITH THE IMMUNE SYSTEM AND REGULATE THE DIFFERENTIATION OF MONOCYTES INTO OSTEOCLASTS. SYNOVIAL HYPERPLASIA IS ANOTHER CHARACTERISTIC OF RA, REFLECTING NOT ONLY AN IMBALANCE BETWEEN PROLIFERATION AND APOPTOSIS, BUT ALSO THE MIGRATION OF CELLS INTO THE SYNOVIAL TISSUE. GENE TRANSFER EXPERIMENTS HAVE BEEN USED AS IMPORTANT TOOLS FOR THE UNDERSTANDING OF MOLECULAR AND CELLULAR CHANGES THAT CHARACTERIZE THE ACTIVATED RA SYNOVIAL FIBROBLASTS. ACTIVATED SYNOVIAL FIBROBLASTS CAN INVADE CARTILAGE AND BONE. SYNOVIAL ACTIVATION IS DRIVEN BY CYTOKINES, SUCH AS TNFALPHA AND IL-1, AS WELL AS IL-15, 16, 17, 18, 22, 23, BUT ALSO BY CYTOKINE-INDEPENDENT MECHANISMS THAT INVOLVE THE INNATE IMMUNE SYSTEM (I.E. TLRS), A UNIQUE COMMUNICATION NETWORK OF MICROPARTICLES AND EPIGENETIC CHANGES (E.G. L1 RETROELEMENTS). 2006 17 6245 34 THE MECHANISMS UNDERLYING CHRONIC INFLAMMATION IN RHEUMATOID ARTHRITIS FROM THE PERSPECTIVE OF THE EPIGENETIC LANDSCAPE. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC INFLAMMATORY AUTOIMMUNE DISEASE THAT IS CHARACTERIZED BY SYNOVIAL HYPERPLASIA AND PROGRESSIVE JOINT DESTRUCTION. THE ACTIVATION OF RA SYNOVIAL FIBROBLASTS (SFS), ALSO CALLED FIBROBLAST-LIKE SYNOVIOCYTES (FLS), CONTRIBUTES SIGNIFICANTLY TO PERPETUATION OF THE DISEASE. GENETIC AND ENVIRONMENTAL FACTORS HAVE BEEN REPORTED TO BE INVOLVED IN THE ETIOLOGY OF RA BUT ARE INSUFFICIENT TO EXPLAIN IT. IN RECENT YEARS, ACCUMULATING RESULTS HAVE SHOWN THE POTENTIAL ROLE OF EPIGENETIC MECHANISMS, INCLUDING HISTONE MODIFICATIONS, DNA METHYLATION, AND MICRORNAS, IN THE DEVELOPMENT OF RA. EPIGENETIC MECHANISMS REGULATE CHROMATIN STATE AND GENE TRANSCRIPTION WITHOUT ANY CHANGE IN DNA SEQUENCE, RESULTING IN THE ALTERATION OF PHENOTYPES IN SEVERAL CELL TYPES, ESPECIALLY RASFS. EPIGENETIC CHANGES POSSIBLY PROVIDE RASFS WITH AN ACTIVATED PHENOTYPE. IN THIS PAPER, WE REVIEW THE ROLES OF EPIGENETIC MECHANISMS RELEVANT FOR THE PROGRESSION OF RA. 2016 18 6218 31 THE JOINT SYNOVIUM: A CRITICAL DETERMINANT OF ARTICULAR CARTILAGE FATE IN INFLAMMATORY JOINT DISEASES. THE SYNOVIUM CONSTITUTES THE ENVELOPE OF ARTICULAR JOINTS AND IS A CRITICAL PROVIDER OF SYNOVIAL FLUID COMPONENTS AND ARTICULAR CARTILAGE NUTRIENTS. ITS INFLAMMATION IS A PREDOMINANT FEATURE AND CAUSE OF JOINT DEGENERATION IN DISEASES AS DIVERSE AS RHEUMATOID, PSORIATIC, JUVENILE AND IDIOPATHIC ARTHRITIS, AND LUPUS, GOUT AND LYME DISEASE. THESE INFLAMMATORY JOINT DISEASES (IJDS) ARE DUE TO A WIDE VARIETY OF GENETIC, EPIGENETIC AND ENVIRONMENTAL FACTORS THAT TRIGGER, PROMOTE, AND PERPETUATE JOINT DESTABILIZATION. IN SPITE OF THIS VARIETY OF CAUSES, IJDS SHARE MAIN PATHOLOGICAL FEATURES, NAMELY INFLAMMATION OF THE JOINT SYNOVIUM (SYNOVITIS) AND PROGRESSIVE DEGENERATION OF ARTICULAR CARTILAGE. IN ADDITION TO BEING A DRIVING FORCE BEHIND THE DESTRUCTION OF ARTICULAR CARTILAGE IN IJD, SYNOVITIS IS ALSO INCREASINGLY BEING RECOGNIZED AS A SIGNIFICANT CONTRIBUTOR OF ARTICULAR CARTILAGE DEGENERATION IN OSTEOARTHRITIS, A DISEASE PRIMARILY DUE TO AGING- OR TRAUMA-RELATED WEAR AND TEAR OF CARTILAGE SURFACES. IN VIEW OF THIS IMPORTANT ROLE OF THE SYNOVIUM IN DETERMINING THE FATE OF ARTICULAR CARTILAGE, THIS REVIEW FOCUSES ON ITS UNDERLYING MECHANISMS IN THE PATHOLOGY OF IJD. WE ADDRESS THE ROLES OF SYNOVIAL FIBROBLASTS, MACROPHAGES AND ENDOTHELIAL CELLS IN THE MAINTENANCE OF JOINT HEALTH AND IN THE DESTRUCTION OF ARTICULAR CARTILAGE INTEGRITY DURING IJD. MOLECULAR MECHANISMS THAT HAVE BEEN RECENTLY SHOWN TO GOVERN THE PATHOLOGICAL ACTIVITIES OF THE RESIDENT SYNOVIAL CELLS ARE HIGHLIGHTED. FINALLY, ADVANTAGES AND DISADVANTAGES OF TARGETING THESE NEW MOLECULAR MECHANISMS FOR PREVENTING CARTILAGE DEGENERATION DUE TO CHRONIC INFLAMMATION ARE ALSO DISCUSSED. 2017 19 2508 29 EPIGENETICS AND OSTEOARTHRITIS. OSTEOARTHRITIS (OA) IS THE MOST COMMON FORM OF JOINT DISEASE AND THE LEADING CAUSE OF CHRONIC DISABILITY IN MIDDLE-AGED AND OLDER POPULATIONS. THE DEVELOPMENT OF DISEASE-MODIFYING THERAPY FOR OA CURRENTLY FACES MAJOR OBSTACLES LARGELY BECAUSE THE REGULATORY MECHANISMS FOR THE FUNCTION OF JOINT TISSUE CELLS REMAIN UNCLEAR. PREVIOUS STUDIES HAVE FOUND THAT THE ALTERATIONS IN GENE EXPRESSION OF SPECIFIC TRANSCRIPTION FACTORS (TFS), PRO- OR ANTI-INFLAMMATORY CYTOKINES, MATRIX PROTEINASES AND EXTRACELLULAR MATRIX (ECM) PROTEINS IN ARTICULAR CARTILAGE MAY BE INVOLVED IN THE DEVELOPMENT OF OA. HOWEVER, THE REGULATORY MECHANISMS FOR THE EXPRESSION OF THOSE GENES IN OA CHONDROCYTES ARE LARGELY UNKNOWN. THE RECENT ADVANCES IN EPIGENETIC STUDIES HAVE SHED LIGHTS ON THE IMPORTANCE OF EPIGENETIC REGULATION OF GENE EXPRESSION IN THE DEVELOPMENT OF OA. IN THIS REVIEW, WE SUMMARIZE AND DISCUSS THE RECENT STUDIES ON THE REGULATORY ROLES OF VARIOUS EPIGENETIC MECHANISMS IN THE EXPRESSION OF GENES FOR SPECIFIC TFS, CYTOKINES, ECM PROTEINS AND MATRIX PROTEINASES, AS WELL THE SIGNIFICANCE OF THESE EPIGENETIC MECHANISMS IN THE PATHOGENESIS OF OA. 2015 20 6884 28 [RHEUMATOID ARTHRITIS]. RHEUMATOID ARTHRITIS ABSTRACT. RHEUMATOID ARTHRITIS (RA) IS THE MOST FREQUENT CHRONIC INFLAMMATORY JOINT DISEASE WITH A PREVALENCE OF APPROXIMATELY 1% WORLDWIDE. THE PATHOGENESIS IS A COMPLEX INTERPLAY OF GENETIC, EPIGENETIC, AND ENVIRONMENTAL FACTORS, WHICH ARE STILL INCOMPLETELY UNDERSTOOD. THE DISEASE IS CHARACTERIZED BY A POLYARTICULAR SYNOVITIS WITH SYMMETRICAL INVOLVEMENT OF SMALL AND LARGE JOINTS. THE MAJORITY OF PATIENTS HAS DETECTABLE AUTOANTIBODIES IN THE SERUM, RHEUMATOID FACTOR AND ANTI-CCP ANTIBODIES WHICH ARE SPECIFIC FOR RA. THE UNCONTROLLED CHRONIC JOINT INFLAMMATION RESULTS IN DESTRUCTIVE CHANGES OF JOINT CARTILAGE AND BONE. AN EARLY DIAGNOSIS AND INITIATION OF TREATMENT IS THEREFORE OF CENTRAL IMPORTANCE. DISEASE-MODIFYING ANTI-RHEUMATIC DRUGS (DMARD) ARE ABLE TO INHIBIT JOINT DESTRUCTION AND SHOULD BE STARTED AS SOON AS POSSIBLE. THERAPY SHOULD BE TARGETED TO REACH A STATE OF REMISSION. THE INTRODUCTION OF HIGHLY EFFECTIVE BIOLOGIC AND TARGETED SYNTHETIC DMARD HAS ALLOWED TO REACH THIS GOAL OF THERAPY IN MANY PATIENTS AND TO PREVENT DISABILITY. HOWEVER, RISKS OF MEDICATION NEED TO BE CONSIDERED, AS WELL AS COMORBIDITIES. 2023