1 6218 121 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 2 484 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 3 1878 31 EMERGING ROLES OF LONG NONCODING RNA IN CHONDROGENESIS, OSTEOGENESIS, AND OSTEOARTHRITIS. OSTEOARTHRITIS (OA) IS THE MOST PREVALENT AGE-RELATED DEBILITATING JOINT DISEASE, AND IS CHARACTERIZED PRIMARILY BY ARTICULAR CARTILAGE DEGRADATION AND SUBCHONDRAL BONE LESIONS. IT IS ALSO THE LEADING CAUSE OF CHRONIC MORBIDITY IN OLDER POPULATIONS. THE ETIOLOGY OF OA IS MULTIFACTORIAL, WITH THE UNDERLYING REGULATORY MECHANISMS REMAINING LARGELY UNKNOWN. LONG NONCODING RNA (LNCRNA) IS A GROUP OF NONCODING RNAS DEFINED AS BEING >200 NUCLEOTIDES IN LENGTH. INCREASING EVIDENCE DEMONSTRATES THAT MANY LNCRNAS SERVE AS CRITICAL REGULATORS OF CHONDROGENESIS AND BONE AND CARTILAGE HOMEOSTASIS, THEREBY INFLUENCING OA DEVELOPMENT. IN THIS REVIEW, WE HIGHLIGHT THE CURRENT UNDERSTANDING CONCERNING LNCRNAS, INCLUDING THEIR PHYSICAL FEATURES, BIOLOGICAL FUNCTIONS, AND POTENTIAL ROLES IN CHONDROGENESIS, OSTEOGENESIS, AND OA. THIS INFORMATION MAY SHED NEW LIGHT ON THE EPIGENETIC REGULATION OF CARTILAGE AND SUBSTANTIATE LNCRNAS AS NOVEL THERAPEUTIC TARGETS IN OA. 2019 4 4880 29 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 5 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 6 757 37 CARTILAGE REPAIR BY MESENCHYMAL STEM CELLS: CLINICAL TRIAL UPDATE AND PERSPECTIVES. OSTEOARTHRITIS IS A DEGENERATIVE DISEASE OF JOINTS WITH DESTRUCTION OF ARTICULAR CARTILAGE ASSOCIATED WITH SUBCHONDRAL BONE HYPERTROPHY AND INFLAMMATION. OA IS THE LEADING CAUSE OF JOINT PAIN RESULTING IN SIGNIFICANT WORSENING OF THE QUALITY-OF-LIFE IN THE ELDERLY. NUMEROUS EFFORTS HAVE BEEN SPENT TO OVERCOME THE INHERENTLY POOR HEALING ABILITY OF ARTICULAR CARTILAGE. MESENCHYMAL STEM CELLS (MSCS) HAVE BEEN IN THE LIMELIGHT OF CELL-BASED THERAPIES TO PROMOTE CARTILAGE REPAIR. DESPITE PROGRESSIVE ADVANCEMENTS IN MSC MANIPULATION AND THE INTRODUCTION OF VARIOUS BIOACTIVE SCAFFOLDS AND GROWTH FACTORS IN PRECLINICAL STUDIES, CURRENT CLINICAL TRIALS ARE STILL AT EARLY STAGES WITH PRELIMINARY AIMS TO EVALUATE SAFETY, FEASIBILITY AND EFFICACY. THIS REVIEW SUMMARISES RECENTLY REPORTED MSC-BASED CLINICAL TRIALS AND DISCUSSES NEW RESEARCH DIRECTIONS WITH PARTICULAR FOCUS ON THE POTENTIAL APPLICATION OF MSC-DERIVED EXTRACELLULAR VEHICLES, MIRNAS AND ADVANCED GENE EDITING TECHNIQUES WHICH MAY SHED LIGHT ON THE DEVELOPMENT OF NOVEL TREATMENT STRATEGIES. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: THIS REVIEW SUMMARISES RECENT MSC-RELATED CLINICAL RESEARCH THAT FOCUSES ON CARTILAGE REPAIR. WE ALSO PROPOSE A NOVEL POSSIBLE TRANSLATIONAL DIRECTION FOR HYALINE CARTILAGE FORMATION AND A NEW PARADIGM MAKING USE OF EXTRA-CELLULAR SIGNALLING AND EPIGENETIC REGULATION IN THE APPLICATION OF MSCS FOR CARTILAGE REPAIR. 2017 7 4347 27 MIR-140 ATTENUATES THE PROGRESSION OF EARLY-STAGE OSTEOARTHRITIS BY RETARDING CHONDROCYTE SENESCENCE. OSTEOARTHRITIS (OA) IS A MAJOR CAUSE OF JOINT PAIN AND DISABILITY, AND CHONDROCYTE SENESCENCE IS A KEY PATHOLOGICAL PROCESS IN OA AND MAY BE A TARGET OF NEW THERAPEUTICS. MICRORNA-140 (MIR-140) PLAYS A PROTECTIVE ROLE IN OA, BUT LITTLE IS KNOWN ABOUT ITS EPIGENETIC EFFECT ON CHONDROCYTE SENESCENCE. IN THIS STUDY, WE FIRST VALIDATED THE FEATURES OF CHONDROCYTE SENESCENCE CHARACTERIZED BY INCREASED CELL CYCLE ARREST IN THE G0/G1 PHASE AND THE EXPRESSION OF SENESCENCE-ASSOCIATED BETA-GALACTOSIDASE (SA-BETAGAL), P16(INK4A), P21, P53, AND GAMMAH2AX IN HUMAN KNEE OA. THEN, WE REVEALED IN INTERLEUKIN 1BETA (IL-1BETA)-INDUCED OA CHONDROCYTES IN VITRO THAT PRETRANSFECTION WITH MIR-140 EFFECTIVELY INHIBITED THE EXPRESSION OF SA-BETAGAL, P16(INK4A), P21, P53, AND GAMMAH2AX. FURTHERMORE, IN VIVO RESULTS FROM TRAUMA-INDUCED EARLY-STAGE OA RATS SHOWED THAT INTRA-ARTICULARLY INJECTED MIR-140 COULD RAPIDLY REACH THE CHONDROCYTE CYTOPLASM AND INDUCE MOLECULAR CHANGES SIMILAR TO THE IN VITRO RESULTS, RESULTING IN A NOTICEABLE ALLEVIATION OF OA PROGRESSION. FINALLY, BIOINFORMATICS ANALYSIS PREDICTED THE POTENTIAL TARGETS OF MIR-140 AND A MECHANISTIC NETWORK BY WHICH MIR-140 REGULATES CHONDROCYTE SENESCENCE. COLLECTIVELY, MIR-140 CAN EFFECTIVELY ATTENUATE THE PROGRESSION OF EARLY-STAGE OA BY RETARDING CHONDROCYTE SENESCENCE, CONTRIBUTING NEW EVIDENCE OF THE INVOLVEMENT OF MIR-MEDIATED EPIGENETIC REGULATION OF CHONDROCYTE SENESCENCE IN OA PATHOGENESIS. 2020 8 5145 36 POTENTIAL ROLE OF NUTRACEUTICALS VIA TARGETING A WNT/BETA-CATENIN AND NF-KAPPAB PATHWAY IN TREATMENT OF OSTEOARTHRITIS. OSTEOARTHRITIS (OA) IS A DISEASE DUE TO THE AGING OF THE ARTICULAR CARTILAGE, A POST-MITOTIC TISSUE THAT STAYS FUNCTIONING UNTIL PRIMARY HOMEOSTATIC PROCESSES FAIL. BECAUSE OF PAIN AND DISABILITY, OA SIGNIFICANTLY INFLUENCES NATIONAL HEALTHCARE EXPENSES AND PATIENT QUALITY OF LIFE. IT IS A WHOLE-JOINT ILLNESS CHARACTERIZED BY INFLAMMATORY AND OXIDATIVE SIGNALING PATHWAYS AND SIGNIFICANT EPIGENETIC ALTERATIONS THAT CAUSE CARTILAGE EXTRACELLULAR MATRIX DEGRADATION. THE CANONICAL WNT PATHWAY (WNT/BETA-CATENIN PATHWAY) AND NUCLEAR FACTOR KAPPA B (NF-KAPPAB) SIGNALING PATHWAYS MAY FUNCTION IN JOINT TISSUES BY MODULATING THE ACTIVITY OF SYNOVIAL CELLS, OSTEOBLASTS, AND CHONDROCYTES. HOWEVER, FINDING INNOVATIVE WAYS TO TREAT OSTEOARTHRITIS AND GET THE JOINT BACK TO AVERAGE BALANCE IS STILL A STRUGGLE. NUTRACEUTICALS ARE DIETARY SUPPLEMENTS THAT PROMOTE JOINT HEALTH BY BALANCING ANABOLIC AND CATABOLIC SIGNALS. NEW THERAPEUTIC METHODS FOR OA TREATMENT HAVE BEEN DEVELOPED BASED ON MANY RESEARCH FINDINGS THAT SHOW NUTRACEUTICALS HAVE STRONG ANTI-INFLAMMATION, ANTIOXIDANT, ANTI-BONE RESORPTION, AND ANABOLIC PROPERTIES. FOR THE TREATMENT OF OSTEOARTHRITIS, WE EXPLORE THE POSSIBLE INVOLVEMENT OF NUTRACEUTICALS THAT TARGET THE WNT/BETA-CATENIN AND NF-KAPPAB PATHWAYS. PRACTICAL APPLICATIONS: IN KEEPING WITH THE AGING POPULATION, OSTEOARTHRITIS IS BECOMING MORE WIDESPREAD. IN THIS EXTENSIVE RESEARCH, WE STUDIED THE ROLE OF THE WNT/BETA-CATENIN AND NF-KAPPAB PATHWAY IN OA FORMATION AND PROGRESSION. NUTRACEUTICALS THAT TARGET THESE OA-RELATED SIGNALING PATHWAYS ARE A VIABLE THERAPY OPTION. WNT/BETA-CATENIN AND NF-KAPPAB SIGNALING PATHWAY ARE INHIBITED BY POLYPHENOLS, FLAVONOIDS, ALKALOIDS, AND VITAMINS FROM THE NUTRACEUTICAL CATEGORY, MAKING THEM POSSIBLE THERAPEUTIC DRUGS FOR OA THERAPY. 2022 9 6102 31 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 10 3355 30 HISTONE EXTRACTION FROM HUMAN ARTICULAR CARTILAGE FOR THE STUDY OF EPIGENETIC REGULATION IN OSTEOARTHRITIS. OSTEOARTHRITIS (OA) IS A CHRONIC DISEASE THAT AFFECTS ARTICULAR CARTILAGE, CAUSING ITS DEGENERATION. ALTHOUGH OA IS ONE OF THE MOST PREVALENT PATHOLOGIES GLOBALLY, THERE ARE NO DEFINITIVE TREATMENTS AVAILABLE. RECENTLY, RESEARCH HAS FOCUSED ON ELUCIDATING THE COMPLEX INTERPLAY THAT TAKES PLACE BETWEEN INFLAMMATORY PROCESSES AND EPIGENETIC REGULATION, SHOWING THAT HISTONE POST-TRANSLATIONAL MODIFICATIONS (PTMS) CAN EXERT A PRONOUNCED EFFECT ON THE EXPRESSION OF OA-RELATED GENES. OA CHONDROCYTES ENHANCE THE PRODUCTION OF INTERLEUKIN 1BETA (IL-1BETA) AND INTERLEUKIN 8 (IL-8), WHICH ARE EPIGENETICALLY REGULATED. THESE CYTOKINES UPREGULATE THE SYNTHESIS OF MATRIX METALLOPROTEINASES (MMPS) AND AGGRECANASES, WHICH PROMOTE THE EXTRACELLULAR MATRIX (ECM) DESTRUCTION. THIS MOTIVATES THE STUDY OF HISTONE PTMS TO INVESTIGATE THE EPIGENETIC REGULATION OF PROINFLAMMATORY MOLECULES, BUT THE ABSENCE OF SPECIFIC PROTOCOLS TO EXTRACT HISTONES FROM HUMAN ARTICULAR CARTILAGE HAS COMPLICATED THIS TASK. THE LACK OF EFFECTIVE METHODS CAN BE EXPLAINED BY THE STRUCTURAL COMPLEXITY AND LOW CELLULARITY OF THIS TISSUE, WHICH ARE RESPONSIBLE FOR THE BIOMECHANICAL PROPERTIES THAT ALLOW THE MOVEMENT OF THE JOINT BUT ALSO COMPLICATE HISTONE ISOLATION. HERE, WE PROVIDE A HISTONE EXTRACTION PROCEDURE SPECIFICALLY ADAPTED FOR CRYOPRESERVED HUMAN ARTICULAR CARTILAGE THAT CAN BE USEFUL TO UNDERSTAND EPIGENETIC REGULATION IN OA AND ACCELERATE THE SEARCH FOR NOVEL STRATEGIES. 2022 11 6741 37 WHERE TO STAND WITH STROMAL CELLS AND CHRONIC SYNOVITIS IN RHEUMATOID ARTHRITIS? THE SYNOVIUM EXERCISES ITS MAIN FUNCTION IN JOINT HOMEOSTASIS THROUGH THE SECRETION OF FACTORS (SUCH AS LUBRICIN AND HYALURONIC ACID) THAT ARE CRITICAL FOR THE JOINT LUBRICATION AND FUNCTION. THE MAIN SYNOVIUM CELL COMPONENTS ARE FIBROBLAST-LIKE SYNOVIOCYTES, MESENCHYMAL STROMAL/STEM CELLS AND MACROPHAGE-LIKE SYNOVIAL CELLS. IN THE SYNOVIUM, CELLS OF MESENCHYMAL ORIGIN MODULATE LOCAL INFLAMMATION AND FIBROSIS, AND INTERACT WITH DIFFERENT FIBROBLAST SUBTYPES AND WITH RESIDENT MACROPHAGES. IN PATHOLOGIC CONDITIONS, SUCH AS RHEUMATOID ARTHRITIS, FIBROBLAST-LIKE SYNOVIOCYTES PROLIFERATE ABNORMALLY, RECRUIT MESENCHYMAL STEM CELLS FROM SUBCHONDRAL BONE MARROW, AND INFLUENCE IMMUNE CELL ACTIVITY THROUGH EPIGENETIC AND METABOLIC ADAPTATIONS. THE RESULTING SYNOVIAL HYPERPLASIA LEADS TO SECONDARY CARTILAGE DESTRUCTION, JOINT SWELLING, AND PAIN. IN THE PRESENT REVIEW, WE SUMMARIZE RECENT FINDINGS ON THE MOLECULAR SIGNATURE AND THE ROLES OF STROMAL CELLS DURING SYNOVIAL PANNUS FORMATION AND RHEUMATOID ARTHRITIS PROGRESSION. 2019 12 296 33 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 13 2460 35 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 14 4679 35 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 3829 27 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 16 1547 27 DNA METHYLATION IN OSTEOARTHRITIS. OSTEOARTHRITIS (OA) IS A PREVALENT DISEASE OF ARTICULAR JOINTS AND PRIMARILY CHARACTERIZED BY DEGRADATION AND CALCIFICATION OF ARTICULAR CARTILAGE. PRESENTLY, NO EFFECTIVE TREATMENT OTHER THAN PAIN RELIEF EXISTS AND PATIENTS ULTIMATELY NEED TO UNDERGO REPLACEMENT SURGERY OF THE AFFECTED JOINT. DURING DISEASE PROGRESSION ARTICULAR CHONDROCYTES, THE SINGLE CELL TYPE PRESENT IN ARTICULAR CARTILAGE, SHOW ALTERED TRANSCRIPTIONAL PROFILES AND UNDERGO PHENOTYPIC CHANGES THAT RESEMBLE THE TERMINAL DIFFERENTIATION ROUTE APPARENT IN GROWTH PLATE CHONDROCYTES. HENCE, GIVEN ITS PROMINENT FUNCTION IN BOTH REGULATING GENE EXPRESSION AND MAINTAINING CELLULAR PHENOTYPES, DNA METHYLATION OF CPG DINUCLEOTIDES IS INTENSIVELY STUDIED IN THE CONTEXT OF OA. AN INCREASING NUMBER OF STUDIES HAVE BEEN PUBLISHED THAT EMPLOYED A TARGETED APPROACH ON GENES KNOWN TO PLAY A ROLE IN OA PATHOPHYSIOLOGY. AS OF SUCH, IT HAS BECOME CLEAR THAT OA RESPONSIVE DNA METHYLATION CHANGES SEEM TO MEDIATE DISEASE ASSOCIATED ABERRANT GENE EXPRESSION. FURTHERMORE, ESTABLISHED OA SUSCEPTIBILITY ALLELES SUCH AS GDF5 AND DIO2 APPEAR TO CONFER OA RISK VIA DNA METHYLATION AND RESPECTIVE PATHOPHYSIOLOGICAL EXPRESSION CHANGES. IN MORE RECENT YEARS, GENOME WIDE PROFILING OF DNA METHYLATION IN OA AFFECTED ARTICULAR CARTILAGE HAS EMERGED AS A POWERFUL TOOL TO ADDRESS THE EPIGENETIC CHANGES IN THEIR ENTIRETY, WHICH HAS RESULTED IN THE IDENTIFICATION OF PUTATIVE PATIENT SUBGROUPS AS WELL AS GENERIC OA ASSOCIATED PATHWAYS. 2015 17 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 18 2309 34 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 19 1257 36 CURRENT TRENDS IN EPIGENETIC, CELLULAR AND MOLECULAR PATHWAYS IN MANAGEMENT OF RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS IS A SYSTEMIC CHRONIC POLYARTICULAR AUTOIMMUNE DISORDER OF JOINTS AND JOINT MEMBRANE MAINLY AFFECTING FEET AND HANDS. THE PATHOLOGICAL MANIFESTATION OF THE DISEASE INCLUDES INFILTRATION OF IMMUNE CELLS, HYPERPLASIA OF THE LINING OF SYNOVIUM, FORMATION OF PANNUS AND BONE AND CARTILAGE DESTRUCTION. IF LEFT UNTREATED, THE APPEARANCE OF SMALL FOCAL NECROSIS, ADHESION OF GRANULATION, AND FORMATION OF FIBROUS TISSUE ON THE SURFACE OF ARTICULAR CARTILAGE IS NOTED. THE DISEASE PRIMARILY AFFECTS NEARLY 1% OF THE POPULATION GLOBALLY, WOMEN BEING MORE AFFECTED THAN MEN WITH A RATIO 2:1 AND CAN INITIATE REGARDLESS OF ANY AGE. THE SYNOVIAL FIBROBLAST IN RHEUMATOID ARTHRITIS INDIVIDUALS EXHIBITS AN AGGRESSIVE PHENOTYPE WHICH UPREGULATES THE MANIFESTATION OF PROTOONCOGENES, ADHESIVE COMPOUNDS, INFLAMMATORY CYTOKINES AND MATRIX-DETERIORATING ENZYMES. APART FROM THE INFLAMMATORY EFFECTS OF CYTOKINES, CHEMOKINES ARE ALSO NOTED TO INDUCE SWELLING AND PAIN IN ARTHRITIC INDIVIDUALS BY RESIDING IN SYNOVIAL MEMBRANE AND FORMING PANNUS. THE CURRENT TREATMENT OF RHEUMATOID ARTHRITIS INCLUDES TREATMENT WITH NON-STEROIDAL ANTI-INFLAMMATORY DRUGS, DISEASE-MODIFYING ANTIRHEUMATIC DRUGS, TREATMENT WITH BIOLOGICS SUCH AS INHIBITORS OF TNF-ALPHA, INTERLEUKINS, PLATELET ACTIVATING FACTOR, ETC. WHICH PROVIDES SIGNIFICANT RELIEF FROM SYMPTOMS AND AIDS IN MANAGEMENT OF THE DISEASE. THE CURRENT REVIEW HIGHLIGHTS THE PATHOGENESIS INVOLVED IN THE ONSET OF RHEUMATOID ARTHRITIS AND ALSO COVERS EPIGENETIC, CELLULAR AND MOLECULAR PARAMETERS ASSOCIATED WITH IT TO AID BETTER AND ADVANCED THERAPEUTIC APPROACHES FOR MANAGEMENT OF THE DEBILITATING DISEASE. 2023 20 5109 43 POLYPHENOL-RELATED EPIGENETIC MODIFICATIONS IN OSTEOARTHRITIS: CURRENT THERAPEUTIC PERSPECTIVES. THE HYALINE CARTILAGE IS AN AVASCULAR, ANEURAL AND ALYMPHATIC TISSUE WITH A LIMITED ABILITY TO REPAIR ITSELF. WHEN THE CARTILAGE IS EXPOSED TO SOME KIND OF INJURY, IT USUALLY TRIGGERS OSTEOARTHRITIS (OA), A PREVALENT AND DEGENERATIVE JOINT DISEASE CLOSELY RELATED TO AGING. OA IS BOTH COMPLEX AND MULTIFACTORIAL, AND IS THE MOST COMMON FORM OF ARTHRITIS, BEING POSITIONED AS A MAJOR CAUSE OF PAIN AND DYSFUNCTION IN THE WORLD. IN ADDITION, HIGH OA PREVALENCE CAN GREATLY AFFECT WORK CAPACITY, MAKING THIS DISEASE A SIGNIFICANT SOCIAL PROBLEM, THEREFORE, ITS PREVENTION AND TREATMENT BECOMES A PRIORITY. AT THIS TIME, THERE ARE NUMEROUS THERAPEUTIC STRATEGIES AVAILABLE TO IMPROVE HYALINE CARTILAGE REPAIR BY USING CHONDROCYTES OR MESENCHYMAL CELLS, BUT NEITHER IS EFFECTIVE ENOUGH TO GENERATE FUNCTIONAL AND DURABLE TISSUE REPARATION OVER TIME. IN OA, CHONDROCYTES HAVE AN ABERRANT GENE EXPRESSION AND PHENOTYPE, RESULTING IN A LOSS OF BALANCE BETWEEN ANABOLIC AND CATABOLIC PROCESSES. ENVIRONMENTAL INFLUENCES SUCH AS RADIATION, INFECTION, SMOKING, NUTRIENTS, TOXINS AND STRESS CAN AFFECT GENE EXPRESSION PATTERNS, WHICH MAY CONSTITUTE RISK FACTORS FOR VARIOUS CHRONIC AND DEGENERATIVE DISEASES, SUCH AS OA. IN ADDITION, CONSIDERABLE EVIDENCE SHOWS THAT EPIGENETIC MECHANISMS PLAY AN IMPORTANT ROLE IN OA CHONDROGENESIS AND PATHOGENESIS. NATURAL PLANT-DERIVED PRODUCTS SUCH AS POLYPHENOLS, WHICH ARE SECONDARY METABOLITES CONSIDERED TO HAVE POTENTIAL ACTIVITY TO BLOCK INFLAMMATION IN SEVERAL DEGENERATIVE DISEASES, CAN STIMULATE EPIGENETIC MODIFICATIONS, AND MAY PROVIDE NEW THERAPEUTIC TARGETS AND COST-EFFECTIVE TREATMENTS. THIS REVIEW AIMS TO PRESENT VARIOUS POLYPHENOLBASED THERAPIES CURRENTLY USED FOR THE TREATMENT OF SEVERAL PROGRESSIVE DISEASES, INCLUDING OA. 2016