1 5078 148 PHYSIOLOGY AND PATHOPHYSIOLOGY OF MATRIX METALLOPROTEASES. MATRIX METALLOPROTEASES (MMPS) COMPRISE A FAMILY OF ENZYMES THAT CLEAVE PROTEIN SUBSTRATES BASED ON A CONSERVED MECHANISM INVOLVING ACTIVATION OF AN ACTIVE SITE-BOUND WATER MOLECULE BY A ZN(2+) ION. ALTHOUGH THE CATALYTIC DOMAIN OF MMPS IS STRUCTURALLY HIGHLY SIMILAR, THERE ARE MANY DIFFERENCES WITH RESPECT TO SUBSTRATE SPECIFICITY, CELLULAR AND TISSUE LOCALIZATION, MEMBRANE BINDING AND REGULATION THAT MAKE THIS A VERY VERSATILE FAMILY OF ENZYMES WITH A MULTITUDE OF PHYSIOLOGICAL FUNCTIONS, MANY OF WHICH ARE STILL NOT FULLY UNDERSTOOD. ESSENTIALLY, ALL MEMBERS OF THE MMP FAMILY HAVE BEEN LINKED TO DISEASE DEVELOPMENT, NOTABLY TO CANCER METASTASIS, CHRONIC INFLAMMATION AND THE ENSUING TISSUE DAMAGE AS WELL AS TO NEUROLOGICAL DISORDERS. THIS HAS STIMULATED A FLURRY OF STUDIES INTO MMP INHIBITORS AS THERAPEUTIC AGENTS, AS WELL AS INTO MEASURING MMP LEVELS AS DIAGNOSTIC OR PROGNOSTIC MARKERS. AS WITH MOST PROTEIN FAMILIES, DECIPHERING THE FUNCTION(S) OF MMPS IS DIFFICULT, AS THEY CAN MODIFY MANY PROTEINS. WHICH OF THESE REACTIONS ARE PHYSIOLOGICALLY OR PATHOPHYSIOLOGICALLY RELEVANT IS OFTEN NOT CLEAR, ALTHOUGH STUDIES ON KNOCKOUT ANIMALS, HUMAN GENETIC AND EPIGENETIC, AS WELL AS BIOCHEMICAL STUDIES USING NATURAL OR SYNTHETIC INHIBITORS HAVE PROVIDED INSIGHT TO A GREAT EXTENT. IN THIS REVIEW, WE WILL GIVE AN OVERVIEW OF 23 MEMBERS OF THE HUMAN MMP FAMILY AND DESCRIBE FUNCTIONS, LINKAGES TO DISEASE AND STRUCTURAL AND MECHANISTIC FEATURES. MMPS CAN BE GROUPED INTO SOLUBLE (INCLUDING MATRILYSINS) AND MEMBRANE-ANCHORED SPECIES. WE ADHERE TO THE 'MMP NOMENCLATURE' AND PROVIDE THE READER WITH REFERENCE TO THE MANY, OFTEN DIVERSE, NAMES FOR THIS ENZYME FAMILY IN THE INTRODUCTION. 2011 2 4880 35 OVERVIEW OF MMP-13 AS A PROMISING TARGET FOR THE TREATMENT OF OSTEOARTHRITIS. OSTEOARTHRITIS (OA) IS A COMMON DEGENERATIVE DISEASE CHARACTERIZED BY THE DESTRUCTION OF ARTICULAR CARTILAGE AND CHRONIC INFLAMMATION OF SURROUNDING TISSUES. MATRIX METALLOPROTEINASE-13 (MMP-13) IS THE PRIMARY MMP INVOLVED IN CARTILAGE DEGRADATION THROUGH ITS PARTICULAR ABILITY TO CLEAVE TYPE II COLLAGEN. HENCE, IT IS AN ATTRACTIVE TARGET FOR THE TREATMENT OF OA. HOWEVER, THE DETAILED MOLECULAR MECHANISMS OF OA INITIATION AND PROGRESSION REMAIN ELUSIVE, AND, CURRENTLY, THERE ARE NO INTERVENTIONS AVAILABLE TO RESTORE DEGRADED CARTILAGE. THIS REVIEW FULLY ILLUSTRATES THE INVOLVEMENT OF MMP-13 IN THE INITIATION AND PROGRESSION OF OA THROUGH THE REGULATION OF MMP-13 ACTIVITY AT THE MOLECULAR AND EPIGENETIC LEVELS, AS WELL AS THE STRATEGIES THAT HAVE BEEN EMPLOYED AGAINST MMP-13. THE AIM OF THIS REVIEW IS TO IDENTIFY MMP-13 AS AN ATTRACTIVE TARGET FOR INHIBITOR DEVELOPMENT IN THE TREATMENT OF OA. 2021 3 6004 40 THE AID DILEMMA: INFECTION, OR CANCER? ACTIVATION-INDUCED CYTIDINE DEAMINASE (AID), WHICH IS BOTH ESSENTIAL AND SUFFICIENT FOR FORMING ANTIBODY MEMORY, IS ALSO LINKED TO TUMORIGENESIS. AID IS FOUND IN MANY B LYMPHOMAS, IN MYELOID LEUKEMIA, AND IN PATHOGEN-INDUCED TUMORS SUCH AS ADULT T CELL LEUKEMIA. ALTHOUGH THERE IS NO SOLID EVIDENCE THAT AID CAUSES HUMAN TUMORS, AID-TRANSGENIC AND AID-DEFICIENT MOUSE MODELS INDICATE THAT AID IS BOTH SUFFICIENT AND REQUIRED FOR TUMORIGENESIS. RECENTLY, AID'S ABILITY TO CLEAVE DNA HAS BEEN SHOWN TO DEPEND ON TOPOISOMERASE 1 (TOP1) AND A HISTONE H3K4 EPIGENETIC MARK. WHEN THE LEVEL OF TOP1 PROTEIN IS DECREASED BY AID ACTIVATION, IT INDUCES IRREVERSIBLE CLEAVAGE IN HIGHLY TRANSCRIBED TARGETS. THIS FINDING AND OTHERS LED TO THE IDEA THAT THERE IS AN EVOLUTIONARY LINK BETWEEN MEIOTIC RECOMBINATION AND CLASS SWITCH RECOMBINATION, WHICH SHARE H3K4 TRIMETHYL, TOPOISOMERASE, THE MRN COMPLEX, MISMATCH REPAIR FAMILY PROTEINS, AND EXONUCLEASE 3. AS TOP1 HAS RECENTLY BEEN SHOWN TO BE INVOLVED IN MANY TRANSCRIPTION-ASSOCIATED GENOME INSTABILITIES, IT IS LIKELY THAT AID TOOK ADVANTAGE OF BASIC GENOME INSTABILITY OR DIVERSIFICATION TO EVOLVE ITS MECHANISM FOR IMMUNE DIVERSITY. AID TARGETS ARE THEREFORE NOT HIGHLY SPECIFIC TO IMMUNOGLOBULIN GENES AND ARE RELATIVELY ABUNDANT, ALTHOUGH THEY HAVE STRICT REQUIREMENTS FOR TRANSCRIPTION-INDUCED H3K4 TRIMETHYL MODIFICATION AND REPETITIVE SEQUENCES PRONE TO FORMING NON-B STRUCTURES. INEVITABLY, AID-DEPENDENT CLEAVAGE TAKES PLACE IN NONIMMUNOGLOBULIN TARGETS AND EVENTUALLY CAUSES TUMORS. HOWEVER, BATTLES AGAINST INFECTION ARE WAGED IN THE CONTEXT OF ACUTE EMERGENCIES, WHILE TUMORIGENESIS IS RATHER A CHRONIC, LONG-TERM PROCESS. IN THE INTEREST OF SURVIVAL, VERTEBRATES MUST HAVE EVOLVED AID TO PREVENT INFECTION DESPITE ITS LONG-TERM RISK OF CAUSING TUMORIGENESIS. 2012 4 620 61 BIOCHEMISTRY AND MOLECULAR BIOLOGY OF GELATINASE B OR MATRIX METALLOPROTEINASE-9 (MMP-9): THE NEXT DECADE. RESEARCH ON MATRIX METALLOPROTEINASES (MMPS) AND IN PARTICULAR ON GELATINASE B, ALIAS MMP-9, HAS GROWN EXPONENTIALLY IN THE DECADE 2003-2012. STRUCTURAL DETAILS ABOUT FLEXIBILITY OF MMP-9 MONOMERS, TOGETHER WITH GLYCOSYLATION, OLIGOMERIZATION, HETEROGENEITY AND INSTABILITY OF THE WILDTYPE ENZYME EXPLAIN WHY CRYSTALLOGRAPHY EXPERIMENTS HAVE NOT YET BEEN SUCCESSFUL FOR THE INTACT ENZYME. MMP-9 MAY BE VIEWED AS A MULTIDOMAIN ENZYME IN WHICH THE HEMOPEXIN, THE O-GLYCOSYLATED AND THE CATALYTIC DOMAINS YIELD SUPPORT FOR ATTACHMENT, ARTICULATION AND CATALYSIS, RESPECTIVELY. THE STEPWISE PROTEOLYTIC ACTIVATION OF THE INACTIVE ZYMOGEN INTO A CATALYTICALLY ACTIVE FORM BECOMES GRADUALLY BETTER UNDERSTOOD. PRIMING OF ACTIVATION BY MMP-3 MAY BE EXECUTED BY MEPRINS THAT DESTABILIZE THE INTERACTION OF THE AMINOTERMINUS WITH THE THIRD FIBRONECTIN REPEAT. ALTERNATIVELY, AUTOCATALYTIC ACTIVATION MAY OCCUR IN THE PRESENCE OF MOLECULES THAT TIGHTLY BIND TO THE CATALYTIC SITE AND THAT PUSH THE CYSTEIN RESIDUE IN THE PRODOMAIN AWAY FROM THE CATALYTIC ZINC ION. THANKS TO THE DEVELOPMENT OF DEGRADOMICS TECHNOLOGIES, SUBSTRATE REPERTOIRES OF MMP-9 HAVE BEEN DEFINED, BUT IT REMAINS A CHALLENGE TO DETERMINE AND PROVE WHICH SUBSTRATES ARE BIOLOGICALLY RELEVANT. THE SUBSTRATE REPERTOIRE HAS BEEN ENLARGED FROM EXTRACELLULAR TO MEMBRANE-BOUND AND EFFICIENT INTRACELLULAR SUBSTRATES, SUCH AS CRYSTALLINS, TUBULINS AND ACTINS. BIOLOGICAL STUDIES OF MMP-9 HAVE TUNED THE FIELD FROM BEING PRIMARILY CANCER-ORIENTED TOWARDS VASCULAR AND INFLAMMATORY RESEARCH. IN TUMOR BIOLOGY, IT HAS BEEN INCREASINGLY APPRECIATED THAT MMP-9 FROM INFLAMMATORY CELLS, PARTICULARLY NEUTROPHILS, CO-DETERMINES PROGNOSIS AND OUTCOME. ASIDE FROM THE CATALYTIC FUNCTIONS EXECUTED BY AMINOTERMINAL DOMAINS OF MMP-9, THE CARBOXYTERMINAL HEMOPEXIN (PEX) DOMAIN OF GELATINASE B EXERTS NON-CATALYTIC ANTI-APOPTOTIC SIGNALING EFFECTS. THE RECOGNITION THAT GELATINASE B IS INDUCED BY MANY PRO-INFLAMMATORY CYTOKINES, WHEREAS ITS INHIBITORS ARE INCREASED BY ANTI-INFLAMMATORY CYTOKINES, HAS GENERATED INTEREST TO TARGET MMP-9 IN ACUTE LETHAL CONDITIONS, SUCH AS BACTERIAL MENINGITIS, SEPSIS AND ENDOTOXIN SHOCK, AND IN ACUTE EXACERBATIONS OF CHRONIC DISEASES. PREVIOUSLY DESCRIBED TRANSCRIPTIONAL REGULATION OF MMP-9 IS COMPLEMENTED BY EPIGENETIC CHECKPOINTS, INCLUDING HISTONE MODIFICATIONS AND MICRORNAS. BECAUSE ACTIVATION OF PROMMP-9 MAY BE EXECUTED BY OTHER MMPS, THE THERAPEUTIC DOGMA THAT MMP INHIBITORS NEED TO BE HIGHLY SELECTIVE MAY BE KEYED DOWN FOR THE TREATMENT OF LIFE-THREATENING CONDITIONS. WHEN INFLAMMATION AND MMP-9 FULFILL BENEFICIAL FUNCTIONS TO CLEAR DAMAGING PROTEIN COMPLEXES, SUCH AS IN SYSTEMIC AUTOIMMUNE DISEASES, THERAPEUTIC MMP INHIBITION HAS TO BE AVOIDED. IN MMP9 GENE KNOCKOUT MICE, SPECIFIC SPONTANEOUS PHENOTYPES EMERGED WITH EFFECTS ON THE SKELETAL, REPRODUCTIVE AND NERVOUS SYSTEMS. THESE FINDINGS NOT ONLY HAVE CLINICAL CORRELATES IN BONE GROWTH AND FERTILITY, BUT ALSO STIMULATE RESEARCH ON THE ROLES OF MMPS AND MMP-9 IN ENDOCRINOLOGY, IMMUNOLOGY AND THE NEUROSCIENCES. MMP9-DEFICIENT MICE ARE VALUABLE TOOLS TO DEFINE MMP-9 SUBSTRATES IN VIVO AND TO STUDY THE ROLE OF THIS ENZYME IN ANIMAL MODELS OF INFLAMMATORY, VASCULAR, NEOPLASTIC AND DEGENERATIVE DISEASES. FUTURE CHALLENGES INCLUDE SOLVING THE CRYSTAL STRUCTURE, DEFINITION OF THE FUNCTIONS OF COVALENT OLIGOMERS AND HETEROMERS IN BIOLOGY AND PATHOLOGY, LIFE-IMAGING OF MMP-9 ACTIVITY, SUBSTRATE DETERMINATION IN SITU AND THE STUDY OF INHIBITOR EFFECTS ON FERTILITY, CANCER AND INFLAMMATION AND IN NEUROBIOLOGY AND REGENERATIVE MEDICINE. SUCH STUDIES WILL BETTER DEFINE CONDITIONS IN WHICH INHIBITION OF MMP-9 IS BENEFICIAL OR HAS TO BE AVOIDED. 2013 5 484 35 ARTICULAR CARTILAGE CHANGES IN MATURING ATHLETES: NEW TARGETS FOR JOINT REJUVENATION. CONTEXT: ARTICULAR CARTILAGE HAS A UNIQUE FUNCTIONAL ARCHITECTURE CAPABLE OF PROVIDING A LIFETIME OF PAIN-FREE JOINT MOTION. THIS TISSUE, HOWEVER, UNDERGOES SUBSTANTIAL AGE-RELATED PHYSIOLOGIC, MECHANICAL, BIOCHEMICAL, AND FUNCTIONAL CHANGES THAT REDUCE ITS ABILITY TO OVERCOME THE EFFECTS OF MECHANICAL STRESS AND INJURY. MANY FACTORS AFFECT JOINT FUNCTION IN THE MATURING ATHLETE-FROM CHONDROCYTE SURVIVAL AND METABOLISM TO STRUCTURAL COMPOSITION AND GENETIC/EPIGENETIC FACTORS GOVERNING CARTILAGE AND SYNOVIUM. AN EVALUATION OF AGE-RELATED CHANGES FOR JOINT HOMEOSTASIS AND RISK FOR OSTEOARTHRITIS IS IMPORTANT TO THE DEVELOPMENT OF NEW STRATEGIES TO REJUVENATE AGING JOINTS. OBJECTIVE: THIS REVIEW SUMMARIZES THE CURRENT LITERATURE ON THE BIOCHEMICAL, CELLULAR, AND PHYSIOLOGIC CHANGES OCCURRING IN AGING ARTICULAR CARTILAGE. DATA SOURCES: PUBMED (1969-2013) AND PUBLISHED BOOKS IN SPORTS HEALTH, CARTILAGE BIOLOGY, AND AGING. STUDY SELECTION: KEYWORDS INCLUDED AGING, ATHLETE, ARTICULAR CARTILAGE, EPIGENETICS, AND FUNCTIONAL PERFORMANCE WITH AGE. STUDY DESIGN: SYSTEMATIC REVIEW. LEVEL OF EVIDENCE: LEVEL 3. DATA EXTRACTION: TO BE INCLUDED, RESEARCH QUESTIONS ADDRESSED THE EFFECT OF AGE-RELATED CHANGES ON PERFORMANCE, ARTICULAR CARTILAGE BIOLOGY, MOLECULAR MECHANISM, AND MORPHOLOGY. RESULTS: THE MATURE ATHLETE FACES CHALLENGES IN MAINTAINING CARTILAGE HEALTH AND JOINT FUNCTION DUE TO AGE-RELATED CHANGES TO ARTICULAR CARTILAGE BIOLOGY, MORPHOLOGY, AND PHYSIOLOGY. THESE CHANGES INCLUDE CHONDROCYTE LOSS AND A DECLINE IN METABOLIC RESPONSE, ALTERATIONS TO MATRIX AND SYNOVIAL TISSUE COMPOSITION, AND DYSREGULATION OF REPARATIVE RESPONSES. CONCLUSION: ALTHOUGH PHYSICAL DECLINE HAS BEEN REGARDED AS A NORMAL PART OF AGING, MANY INDIVIDUALS MAINTAIN OVERALL FITNESS AND ENJOY TARGETED IMPROVEMENT TO THEIR ATHLETIC CAPACITY THROUGHOUT LIFE. HEALTHY ARTICULAR CARTILAGE AND JOINTS ARE NEEDED TO MAINTAIN ATHLETIC PERFORMANCE AND GENERAL ACTIVITIES. GENETIC AND POTENTIALLY REVERSIBLE EPIGENETIC FACTORS INFLUENCE CARTILAGE PHYSIOLOGY AND ITS RESPONSE TO MECHANICAL AND INJURIOUS STIMULI. IMPROVED UNDERSTANDINGS OF THE PHYSICAL AND MOLECULAR CHANGES TO ARTICULAR CARTILAGE WITH AGING ARE IMPORTANT TO DEVELOP SUCCESSFUL STRATEGIES FOR JOINT REJUVENATION. 2014 6 6218 29 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 7 5585 45 ROLE OF OXIDATIVE STRESS AND GENETIC POLYMORPHISM OF MATRIX METALLOPROTEINASE-2 AND TISSUE INHIBITOR OF METALLOPROTEINASE-2 IN COPD. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD), A COMPLAINT DESCRIBED BY PROGRESSIVE AND INADEQUATELY REVERSIBLE LIMITATION IN LUNGS WITH SYSTEMIC INFLAMMATION, IS LARGELY CURRENT IN INDIA. THERE'S NO REMEDY AVAILABLE SO FAR IT IS, THUS, IMPERATIVE TO UNDERSTAND THE UNDERPINNING PATHOGENESIS OF THE COMPLAINANT. A SET OF PROTEASES KNOWN AS MATRIX METALLOPROTEINASE (MMPS) ARE ESPECIALLY INVOLVED IN THE PROCESS OF ALVEOLAR DESTRUCTION AND MUCUS HYPERSECRETION. THERE ARE RESPONSIBLE FACTORS IN AN INHERITABLE POSITION TO CONTROL COPD LIKE MMPS AND TIMPS (TISSUE INHIBITOR OF METALLOPROTEINASES). MMPS DEGRADE EXTRACELLULAR MATRIX AND LEAD TO THE PATHOGENESIS OF COPD [1]. TIMPS PROTEINS THAT HELP TO INHIBIT THE MATRIX METALLOPROTEINASES. [2]. THIS REVIEW SUMMARIZES THE IMPLICIT PART OF CRUCIAL MMP-2 AND TIMP-2 IN COPD DISEASE. THOUGH THE CONCEPT SEEMS PROMISING, LIMITED KNOWLEDGE ABOUT THE EXACT FUNCTIONS OF A PARTICULAR MMP IN COPD AND THE COMPLICATIONS OF MMP IN SUBSTRATE AFFINITY MAKES THIS A GRUELING TASK. MMP2 AND TIMP2 BOTH ARE DIRECTLY OR INDIRECTLY REGULATED BY OXIDATIVE STRESS AND EPIGENETIC MECHANISM WHICH REGULATES THEIR EXPRESSIONS. COPD IS A SEDITIOUS RESPONSE TO FACTORS LIKE DUST, SMOKE, ETC., AND TRIGGERS EXTRA-PULMONARY GOODS WHICH CAUSE INFLAMMATION. [3]. THIS REVIEW EXPLAINS THE RELATIONSHIP BETWEEN MMP2 AND TIMP2 IN COPD PATIENTS WITH OXIDATIVE STRESS, ITS IMPACT ON COPD PATHOGENESIS, AND GENE EXPRESSION OF TIMP2 AND MMP2 WITH THEIR DOWNSTREAM EFFECTS. THIS ALSO GIVES SOME INSIGHTS INTO THERAPEUTIC INTERVENTIONS FOR TARGETING THESE ENZYMES. MMP2 AND TIMP2 BOTH PLAY A ROLE IN THE DEVELOPMENT OF COPD AND THEY NEED TO BE STUDIED WITH THE UTMOST FOCUS. 2023 8 3829 30 INVOLVEMENT OF EPIGENETICS IN OSTEOARTHRITIS. OSTEOARTHRITIS (OA) IS THE MOST PREVALENT CHRONIC AGE-RELATED ARTHRITIC DISEASE THAT MAINLY AFFECTS THE DIARTHRODIAL JOINTS. NEVERTHELESS, THERE IS NO TREATMENT CURRENTLY AVAILABLE THAT CAN EFFECTIVELY REDUCE SYMPTOMS OR SLOW DOWN OR STOP DISEASE PROGRESSION. THE LACK OF DISEASE-MODIFYING THERAPIES COULD BE EXPLAINED BY THE COMPLEX PATHOGENESIS OF OA, WHICH IS STILL NOT COMPLETELY UNDERSTOOD. INTERTWINED EPIGENETIC MECHANISMS SUCH AS DNA METHYLATION, HISTONE MODIFICATIONS, AND NONCODING RNAS (NCRNAS) HAVE BEEN INDICATED AS IMPORTANT CELLULAR TOOLS TO MAINTAIN TISSUE HOMEOSTASIS UPON ENVIRONMENTAL CHALLENGES. THE CURRENT REVIEW ILLUSTRATES THAT DYSFUNCTIONAL EPIGENETIC CONTROL MECHANISMS IN THE ARTICULAR CARTILAGE LIKELY PLAY AN IMPORTANT ROLE IN DRIVING OA PATHOPHYSIOLOGY. 2017 9 6227 33 THE LINK OF ORGANOPHOSPHORUS PESTICIDES WITH NEURODEGENERATIVE AND NEURODEVELOPMENTAL DISEASES BASED ON EVIDENCE AND MECHANISMS. ORGANOPHOSPHORUS (OP) COMPOUNDS HAVE BEEN KNOWN AS THE MOST WIDELY USED PESTICIDES DURING THE PAST HALF CENTURY AND THERE HAVE BEEN A HUGE BODY OF LITERATURE REGARDING THEIR ASSOCIATION WITH HUMAN CHRONIC DISEASES. NEURODEGENERATIVE AND NEURODEVELOPMENTAL DISORDERS INCLUDING ALZHEIMER, PARKINSON, AMYOTROPHIC LATERAL SCLEROSIS (ALS), ATTENTION DEFICIT HYPERACTIVITY DISORDER (ADHD), AND AUTISM ARE AMONG THE AFFLICTING NEUROLOGICAL DISEASES WHICH OVERSHADOW HUMAN LIFE AND THEIR HIGHER RISK IN RELATION TO OP EXPOSURES HAVE BEEN UNCOVERED BY EPIDEMIOLOGICAL STUDIES. IN ADDITION, EXPERIMENTAL STUDIES EXPLORING THE UNDERLYING MECHANISMS HAVE PROVIDED SOME EVIDENCE FOR INVOLVEMENT OF CHOLINERGIC DEFICIT, OXIDATIVE STRESS, NEURO-INFLAMMATION, AND EPIGENETIC MODIFICATIONS AS THE PROCESSES WHICH ARE COMMON IN THE TOXICITY OF THE OP AND PATHOPHYSIOLOGY OF THE MENTIONED DISEASES. IN ADDITION, GENETIC MUTATIONS AND POLYMORPHISMS OF DIFFERENT VARIANTS OF SOME GENES LIKE PARAOXONASE HAVE BEEN SHOWN TO BE IMPLICATED IN BOTH SUSCEPTIBILITY TO OPS TOXICITY AND NEUROLOGICAL DISEASES. IN THIS ARTICLE, WE REVIEWED THE EPIDEMIOLOGICAL AS WELL AS EXPERIMENTAL STUDIES EVIDENCING THE ASSOCIATION OF EXPOSURE TO OPS AND INCIDENCE OF NEURODEGENERATIVE AND NEURODEVELOPMENTAL DISEASES. 2018 10 4142 33 MECHANISMS OF RESISTANCE TO TYROSINE KINASE INHIBITORS IN CHRONIC MYELOID LEUKEMIA AND RECENT THERAPEUTIC STRATEGIES TO OVERCOME RESISTANCE. GIVEN ITS RELATIVE RARITY, IT MAY AT FIRST SEEM SURPRISING THAT CHRONIC MYELOID LEUKEMIA (CML) HAS GARNERED SO MUCH ATTENTION OVER THE LAST DECADE. YET, THE ADVANCES IN MOLECULAR PATHOGENESIS THAT HAVE BEEN DERIVED FROM STUDYING THIS LEUKEMIA HAVE CLEARLY BENEFITED ALL OF ONCOLOGY. MOREOVER, THE STRIDES IN DRUG DESIGN AND DEVELOPMENT THAT HAVE ALSO ENSUED AROUND CML HAVE GIVEN RISE TO WHAT OTHERS HAVE CALLED A MOLECULAR REVOLUTION IN CANCER THERAPY. WHILE A MAJORITY OF PATIENTS WITH CHRONIC PHASE CML (CP-CML) HAVE AN EXCELLENT DURABLE RESPONSE TO IMATINIB (GLEEVEC, NOVARTIS, BASEL, SWITZERLAND), A CLEAR MINORITY WILL UNFORTUNATELY HAVE SIGNS OF PRIMARY OR SECONDARY RESISTANCE TO THERAPY. SIGNIFICANT EFFORTS GEARED TOWARD UNDERSTANDING THE MOLECULAR MECHANISMS OF IMATINIB RESISTANCE HAVE YIELDED VALUABLE INSIGHTS INTO THE BIOLOGY OF DRUG TRAFFICKING INTO AND OUT OF CELLS, EPIGENETIC CONTROL OF CELLULAR PROCESSES, ALTERATIONS IN ENZYMATIC STRUCTURES, AND THE RATIONAL STRUCTURAL-BASED DESIGN OF SMALL MOLECULE ENZYME INHIBITORS. THIS REVIEW WILL DESCRIBE THE EFFORTS AT UNDERSTANDING THE PATHOGENESIS OF IMATINIB RESISTANCE AND THE MOLECULAR RATIONALE FOR THE DEVELOPMENT OF SECOND- AND NOW THIRD-GENERATION THERAPIES FOR PATIENTS WITH CML. 2009 11 4783 38 NUTRIGENOMICS IN PARKINSON'S DISEASE: DIVERSITY OF MODULATORY ACTIONS OF POLYPHENOLS ON EPIGENETIC EFFECTS INDUCED BY TOXINS. ALTHOUGH THE PATHOGENESIS OF PARKINSON'S DISEASE (PD) IS NOT COMPLETELY UNDERSTOOD, THERE IS A CONSENSUS THAT IT CAN BE CAUSED BY MULTIFACTORIAL MECHANISMS INVOLVING GENETIC SUSCEPTIBILITY, EPIGENETIC MODIFICATIONS INDUCED BY TOXINS AND MITOCHONDRIAL DYSFUNCTION. IN THE PAST 20 YEARS, GREAT EFFORTS HAVE BEEN MADE IN ORDER TO CLARIFY MOLECULAR MECHANISMS THAT ARE RISK FACTORS FOR THIS DISEASE, AS WELL AS TO IDENTIFY BIOACTIVE AGENTS FOR PREVENTION AND SLOWING DOWN OF ITS PROGRESSION. NUTRACEUTICAL PRODUCTS HAVE RECEIVED SUBSTANTIAL INTEREST DUE TO THEIR NUTRITIONAL, SAFE AND THERAPEUTIC EFFECTS ON SEVERAL CHRONIC DISEASES. THE AIM OF THIS REVIEW WAS TO GATHER THE MAIN EVIDENCE OF THE EPIGENETIC MECHANISMS INVOLVED IN THE NEUROPROTECTIVE EFFECTS OF PHENOLIC COMPOUNDS CURRENTLY UNDER INVESTIGATION FOR THE TREATMENT OF TOXIN-INDUCED PD. THESE STUDIES CONFIRM THAT THE NEUROPROTECTIVE ACTIONS OF POLYPHENOLS INVOLVE COMPLEX EPIGENETIC MODULATIONS, DEMONSTRATING THAT THE INTAKE OF THESE NATURAL COMPOUNDS CAN BE A PROMISING, LOW-COST, PHARMACOGENOMIC STRATEGY AGAINST THE DEVELOPMENT OF PD. 2023 12 3800 36 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 13 296 30 AGING, CELL SENESCENCE, THE PATHOGENESIS AND TARGETED THERAPIES OF OSTEOARTHRITIS. OSTEOARTHRITIS (OA) IS A CHRONIC, DEBILITATING JOINT DISEASE CHARACTERIZED BY PROGRESSIVE DESTRUCTION OF ARTICULAR CARTILAGE. FOR A LONG TIME, OA HAS BEEN CONSIDERED AS A DEGENERATIVE DISEASE, WHILE RECENT OBSERVATIONS INDICATE THE MECHANISMS RESPONSIBLE FOR THE PATHOGENESIS OF OA ARE MULTIFACETED. AGING IS A KEY FACTOR IN ITS DEVELOPMENT. CURRENT TREATMENTS ARE PALLIATIVE AND NO DISEASE MODIFYING ANTI-OSTEOARTHRITIS DRUGS (DMOADS) ARE AVAILABLE. IN ADDITION TO ARTICULAR CARTILAGE DEGRADATION, CELLULAR SENESCENCE, SYNOVIAL INFLAMMATION, AND EPIGENETIC ALTERATIONS MAY ALL HAVE A ROLE IN ITS FORMATION. ACCUMULATING DATA DEMONSTRATE A CLEAR RELATIONSHIP BETWEEN THE SENESCENCE OF ARTICULAR CHONDROCYTES AND OA FORMATION AND PROGRESSION. INHIBITION OF CELL SENESCENCE MAY HELP IDENTIFY NEW AGENTS WITH THE PROPERTIES OF DMOADS. SEVERAL ANTI-CELLULAR SENESCENCE STRATEGIES HAVE BEEN PROPOSED AND THESE INCLUDE SIRTUIN-ACTIVATING COMPOUNDS (STACS), SENOLYTICS, AND SENOMORPHICS DRUGS. THESE AGENTS MAY SELECTIVELY REMOVE SENESCENT CELLS OR AMELIORATE THEIR HARMFUL EFFECTS. THE RESULTS FROM PRECLINICAL EXPERIMENTS AND CLINICAL TRIALS ARE INSPIRING. HOWEVER, MORE STUDIES ARE WARRANTED TO CONFIRM THEIR EFFICACY, SAFETY PROFILES AND ADVERSE EFFECTS OF THESE AGENTS. 2021 14 202 24 ACTIVATION INDUCED CYTIDINE DEAMINASE: AN OLD FRIEND WITH NEW FACES. ACTIVATION INDUCED CYTIDINE DEAMINASE (AID) PROTEIN IS A MEMBER OF APOBEC FAMILY. AID CONVERTS CYTIDINE TO URACIL, WHICH IS A KEY STEP FOR SOMATIC HYPERMUTATION (SHM) AND CLASS SWITCH RECOMBINATION (CSR). AID ALSO PLAYS CRITICAL ROLES IN B CELL PRECURSOR STAGES, REMOVING POLYREACTIVE B CELLS FROM IMMUNE REPERTOIRE. SINCE THE MAIN FUNCTION OF AID IS INDUCING POINT MUTATIONS, DYSREGULATION CAN LEAD TO INCREASED MUTATION LOAD, TRANSLOCATIONS, DISTURBED GENOMIC INTEGRITY, AND LYMPHOMAGENESIS. AS SUCH, EXPRESSION OF AID AS WELL AS ITS FUNCTION IS CONTROLLED STRICTLY AT VARIOUS MOLECULAR STEPS. OTHER MEMBERS OF THE APOBEC FAMILY ALSO PLAY CRUCIAL ROLES DURING CARCINOGENESIS. CONSIDERING ALL THESE FUNCTIONS, AID REPRESENTS A BRIDGE, LINKING CHRONIC INFLAMMATION TO CARCINOGENESIS AND IMMUNE DEFICIENCIES TO AUTOIMMUNE MANIFESTATIONS. 2022 15 2556 26 EPIGENETICS IN RHEUMATOID ARTHRITIS. EPIGENETICS IS A STEADILY GROWING RESEARCH AREA. IN MANY HUMAN DISEASES, ESPECIALLY IN CANCERS, BUT ALSO IN AUTOIMMUNE DISEASES, EPIGENETIC ABERRATIONS HAVE BEEN FOUND. RHEUMATOID ARTHRITIS IS AN AUTOIMMUNE DISEASE CHARACTERIZED BY CHRONIC INFLAMMATION AND DESTRUCTION OF SYNOVIAL JOINTS. EVEN THOUGH THE ETIOLOGY IS NOT YET FULLY UNDERSTOOD, RHEUMATOID ARTHRITIS IS GENERALLY CONSIDERED TO BE CAUSED BY A COMBINATION OF GENETIC PREDISPOSITION, DEREGULATED IMMUNOMODULATION, AND ENVIRONMENTAL INFLUENCES. TO GAIN A BETTER UNDERSTANDING OF THIS DISEASE, RESEARCHERS HAVE BECOME INTERESTED IN STUDYING EPIGENETIC CHANGES IN RHEUMATOID ARTHRITIS. HERE, WE WANT TO REVIEW THE CURRENT KNOWLEDGE ON EPIGENETICS IN RHEUMATOID ARTHRITIS. 2010 16 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 17 6884 31 [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 18 209 42 ACTIVATION-INDUCED CYTIDINE DEAMINASE: IN SICKNESS AND IN HEALTH. ACTIVATION INDUCED CYTIDINE DEAMINASE (AID) IS AN ESSENTIAL ENZYME OF THE ADAPTIVE IMMUNE SYSTEM. ITS CANONICAL ACTIVITY IS RESTRICTED TO B LYMPHOCYTES, PLAYING AN ESSENTIAL ROLE IN THE DIVERSIFICATION OF ANTIBODIES BY ENHANCING SPECIFICITY AND CHANGING AFFINITY. THIS IS POSSIBLE THROUGH ITS DNA DEAMINASE FUNCTION, LEADING TO MUTATIONS IN DNA. IN THE LAST DECADE, AID HAS BEEN ASSIGNED AN ADDITIONAL FUNCTION: THAT OF A POWERFUL DNA DEMETHYLATOR. ADVERSE CELLULAR CONDITIONS SUCH AS CHRONIC INFLAMMATION CAN LEAD TO ITS DEREGULATION AND OVEREXPRESSION. IT IS AN IMPORTANT DRIVER OF B-CELL LYMPHOMA DUE TO ITS NATURAL ABILITY TO MODIFY DNA THROUGH DEAMINATION, LEADING TO MUTATIONS AND EPIGENETIC CHANGES. HOWEVER, THE DEREGULATION OF AID IS NOT RESTRICTED TO LYMPHOID CELLS. RECENT FINDINGS HAVE PROVIDED NEW INSIGHTS INTO THE ROLE THAT THIS PROTEIN PLAYS IN THE DEVELOPMENT OF NON-LYMPHOID CANCERS, WITH SOME RESEARCH SHEDDING LIGHT ON NOVEL AID-DRIVEN MECHANISMS OF CELLULAR TRANSFORMATION. IN THIS REVIEW, WE PROVIDE AN UPDATED NARRATIVE OF THE NORMAL PHYSIOLOGICAL FUNCTIONS OF AID. ADDITIONALLY, WE REVIEW AND DISCUSS THE RECENT RESEARCH STUDIES THAT HAVE IMPLICATED AID IN CARCINOGENESIS IN VARYING TISSUE TYPES INCLUDING LYMPHOID AND NON-LYMPHOID CANCERS. WE REVIEW THE MECHANISMS, WHEREBY AID PROMOTES CARCINOGENESIS AND HIGHLIGHT IMPORTANT AREAS OF FUTURE RESEARCH. 2020 19 3700 36 INFLAMMATORY MEMORY AND TISSUE ADAPTATION IN SICKNESS AND IN HEALTH. OUR BODY HAS A REMARKABLE ABILITY TO REMEMBER ITS PAST ENCOUNTERS WITH ALLERGENS, PATHOGENS, WOUNDS AND IRRITANTS, AND TO REACT MORE QUICKLY TO THE NEXT EXPERIENCE. THIS ACCENTUATED SENSITIVITY ALSO HELPS US TO COPE WITH NEW THREATS. DESPITE MAINTAINING A STATE OF READINESS AND BROADENED RESISTANCE TO SUBSEQUENT PATHOGENS, MEMORIES CAN ALSO BE MALADAPTIVE, LEADING TO CHRONIC INFLAMMATORY DISORDERS AND CANCERS. WITH THE EVER-INCREASING EMERGENCE OF NEW PATHOGENS, ALLERGENS AND POLLUTANTS IN OUR WORLD, THE URGENCY TO UNRAVEL THE MOLECULAR UNDERPINNINGS OF THESE PHENOMENA HAS RISEN TO NEW HEIGHTS. HERE WE REFLECT ON HOW THE FIELD OF INFLAMMATORY MEMORY HAS EVOLVED, SINCE 2007, WHEN RESEARCHERS REALIZED THAT NON-SPECIFIC MEMORY IS CONTAINED IN THE NUCLEUS AND PROPAGATED AT THE EPIGENETIC LEVEL. WE REVIEW THE FLURRY OF RECENT DISCOVERIES REVEALING THAT MEMORY IS NOT JUST A PRIVILEGE OF THE IMMUNE SYSTEM BUT ALSO EXTENDS TO EPITHELIA OF THE SKIN, LUNG, INTESTINE AND PANCREAS, AND TO NEURONS. ALTHOUGH STILL UNFOLDING, EPIGENETIC MEMORIES OF INFLAMMATION HAVE NOW BEEN LINKED TO POSSIBLE BRAIN DISORDERS SUCH AS ALZHEIMER DISEASE, AND TO AN ELEVATED RISK OF CANCER. IN THIS REVIEW, WE CONSIDER THE CONSEQUENCES-GOOD AND BAD-OF THESE EPIGENETIC MEMORIES AND THEIR IMPLICATIONS FOR HUMAN HEALTH AND DISEASE. 2022 20 2460 28 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