1 6276 117 THE PATHOGENIC ROLE OF DYSREGULATED EPIGENETIC MODIFICATIONS IN AUTOIMMUNE DISEASES. AUTOIMMUNE DISEASES CAN BE CHRONIC WITH RELAPSE OF INFLAMMATORY SYMPTOMS, BUT IT CAN BE ALSO ACUTE AND LIFE-THREATENING IF IMMUNE CELLS DESTROY LIFE-SUPPORTING ORGANS, SUCH AS LUPUS NEPHRITIS. THE ETIOPATHOGENESIS OF AUTOIMMUNE DISEASES HAS BEEN REVEALED AS THAT GENETICS AND ENVIRONMENTAL FACTORS-MEDIATED DYSREGULATED IMMUNE RESPONSES CONTRIBUTE TO THE INITIATION AND DEVELOPMENT OF AUTOIMMUNE DISORDERS. HOWEVER, THE CURRENT UNDERSTANDING OF PATHOGENESIS IS LIMITED AND THE UNDERLYING MECHANISM HAS NOT BEEN WELL DEFINED, WHICH LOWS THE DEVELOPMENT OF NOVEL BIOMARKERS AND NEW THERAPEUTIC STRATEGIES FOR AUTOIMMUNE DISEASES. TO IMPROVE THIS, BROADENING AND DEEPENING OUR UNDERSTANDING OF PATHOGENESIS IS AN UNMET NEED. AS GENETIC SUSCEPTIBILITY CANNOT EXPLAIN THE LOW ACCORDANCE RATE OF INCIDENCE IN HOMOZYGOUS TWINS, EPIGENETIC REGULATIONS MIGHT BE AN ADDITIONAL EXPLANATION. THEREFORE, THIS REVIEW WILL SUMMARIZE CURRENT PROGRESS OF STUDIES ON EPIGENETIC DYSREGULATIONS CONTRIBUTING TO AUTOIMMUNE DISEASES, INCLUDING SLE, RHEUMATOID ARTHRITIS (RA), PSORIASIS, TYPE 1 DIABETES (T1D), AND SYSTEMIC SCLEROSIS (SSC), HOPEFULLY PROVIDING OPINIONS ON ORIENTATION OF FUTURE RESEARCH, AS WELL AS DISCUSSING THE CLINICAL UTILIZATION OF POTENTIAL BIOMARKERS AND THERAPEUTIC STRATEGIES FOR THESE DISEASES. 2019 2 395 48 AN UPDATE ON EPIGENETIC REGULATION IN AUTOIMMUNE DISEASES. AUTOIMMUNE DISEASES (AIDS) GENERALLY MANIFEST AS CHRONIC IMMUNE DISORDERS CHARACTERIZED BY SIGNIFICANT HETEROGENEITY AND COMPLEX SYMPTOMS. THE DISCORDANT INCIDENCE OF AIDS BETWEEN MONOZYGOTIC TWINS GUIDED PEOPLE TO ATTACH IMPORTANCE TO ENVIRONMENTAL FACTORS. EPIGENETICS IS ONE OF THE MAJOR WAYS TO BE INFLUENCED, SOME OF THEM CAN EVEN OCCUR YEARS BEFORE CLINICAL DIAGNOSIS. WITH THE ADVENT OF HIGH-THROUGHPUT OMICS TIMES, THE MYSTERIOUS VEIL OF EPIGENETIC MODIFICATION IN AIDS HAS BEEN GRADUALLY UNRAVELED, AND SOME PROGRESS HAS BEEN MADE IN UTILIZING IT AS INDICATORS OF DIAGNOSIS AND DISEASE ACTIVITY. FOR EXAMPLE, THE HYPOMETHYLATED IFI44L PROMOTER IN DIAGNOSING SYSTEMATIC LUPUS ERYTHEMATOSUS (SLE). MORE RECENTLY, NEWLY IDENTIFIED NONCODING RNAS (NCRNAS), INCLUDING LONG NONCODING RNAS (LNCRNAS) AND CIRCULAR RNAS (CIRCRNAS), ARE ALSO BELIEVED TO BE INVOLVED IN THE ETIOLOGY OF AIDS WHILE THE INITIAL FACTOR BEHIND THOSE EPIGENETIC ALTERATIONS CAN BE DIVERSE FROM METABOLISM TO MICROBIOTA. UPDATE AND COMPREHENSIVE INSIGHTS INTO EPIGENETICS IN AIDS CAN HELP US UNDERSTAND THE PATHOGENESIS AND FURTHER ORCHESTRATE IT TO BENEFIT PATIENTS IN THE FUTURE. THEREFORE, WE REVIEWED THE LATEST EPIGENETIC FINDINGS IN SLE, RHEUMATOID ARTHRITIS (RA), TYPE 1 DIABETES (T1D), SYSTEMIC SCLEROSIS (SSC) PRIMARILY FROM CELLULAR LEVELS. 2022 3 4844 39 ONE YEAR IN REVIEW 2019: PATHOGENESIS OF RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC INFLAMMATORY AUTOIMMUNE DISEASE INFLUENCED BY BOTH GENETIC AND ENVIRONMENTAL FACTORS. OVER THE LAST FEW YEARS, PARTICULAR ATTENTION HAS BEEN GIVEN TO NOVEL GENES AND TO THE CLOSE INTERACTION BETWEEN GENETIC FACTORS AND EPIGENETIC MECHANISMS. RESEARCH HAS ALSO FOCUSED ON THE INFLUENCE OF ENVIRONMENTAL FACTORS ON DISEASE DEVELOPMENT, AND ON NEW MECHANISMS OF THE INNATE AND ADAPTIVE IMMUNE SYSTEM THAT CAN INFLUENCE THE DIFFERENT STAGES OF RA. HOWEVER, THERE ARE STILL SEVERAL ASPECTS OF THE DISEASE THAT NEED FURTHER INVESTIGATION. SHEDDING SOME LIGHT ON THE DIFFERENT ASPECTS OF RA PATHOGENESIS WILL HELP TO IMPROVE THE CURRENT DIAGNOSTIC TOOLS AND TO IDENTIFY NEW TARGETS FOR THE DEVELOPMENT OF DISEASE-MODIFYING THERAPIES. THUS, IN THIS REVIEW WE SUMMARISE THE NEW INSIGHTS IN RA PATHOGENESIS, RESULTING FROM LITERATURE RESEARCH DATA PUBLISHED IN THE LAST YEAR. 2019 4 6345 40 THE ROLE OF EPIGENETICS IN AUTOIMMUNE/INFLAMMATORY DISEASE. HISTORICALLY, SYSTEMIC SELF-INFLAMMATORY CONDITIONS WERE CLASSIFIED AS EITHER AUTOINFLAMMATORY AND CAUSED BY THE INNATE IMMUNE SYSTEM OR AUTOIMMUNE AND DRIVEN BY ADAPTIVE IMMUNE RESPONSES. HOWEVER, IT BECAME CLEAR THAT REALITY IS MUCH MORE COMPLEX AND THAT AUTOIMMUNE/INFLAMMATORY CONDITIONS RANGE ALONG AN "INFLAMMATORY SPECTRUM" WITH PRIMARILY AUTOINFLAMMATORY VS. AUTOIMMUNE CONDITIONS RESEMBLING EXTREMES AT EITHER END. EPIGENETIC MODIFICATIONS INFLUENCE GENE EXPRESSION AND ALTER CELLULAR FUNCTIONS WITHOUT MODIFYING THE GENOMIC SEQUENCE. METHYLATION OF CPG DNA DINUCLEOTIDES AND/OR THEIR HYDROXYMETHYLATION, POST-TRANSLATIONAL MODIFICATIONS TO AMINO TERMINI OF HISTONE PROTEINS, AND NON-CODING RNA EXPRESSION ARE MAIN EPIGENETIC EVENTS. THE PATHOPHYSIOLOGY OF AUTOIMMUNE/INFLAMMATORY DISEASES HAS BEEN CLOSELY LINKED WITH DISEASE CAUSING GENE MUTATIONS (RARE) OR A COMBINATION OF GENETIC SUSCEPTIBILITY AND EPIGENETIC MODIFICATIONS ARISING FROM EXPOSURE TO THE ENVIRONMENT (MORE COMMON). OVER RECENT YEARS, PROGRESS HAS BEEN MADE IN UNDERSTANDING MOLECULAR MECHANISMS INVOLVED IN SYSTEMIC INFLAMMATION AND THE CONTRIBUTION OF INNATE AND ADAPTIVE IMMUNE RESPONSES. EPIGENETIC EVENTS HAVE BEEN IDENTIFIED AS (I) CENTRAL PATHOPHYSIOLOGICAL FACTORS IN ADDITION TO GENETIC DISEASE PREDISPOSITION AND (II) AS CO-FACTORS DETERMINING CLINICAL PICTURES AND OUTCOMES IN INDIVIDUALS WITH MONOGENIC DISEASE. THUS, A COMPLETE UNDERSTANDING OF EPIGENETIC CONTRIBUTORS TO AUTOIMMUNE/INFLAMMATORY DISEASE WILL RESULT IN APPROACHES TO PREDICT INDIVIDUAL DISEASE OUTCOMES AND THE INTRODUCTION OF EFFECTIVE, TARGET-DIRECTED, AND TOLERABLE THERAPIES. HERE, WE SUMMARIZE RECENT FINDINGS THAT SIGNIFY THE IMPORTANCE OF EPIGENETIC MODIFICATIONS IN AUTOIMMUNE/INFLAMMATORY DISORDERS ALONG THE INFLAMMATORY SPECTRUM CHOOSING THREE EXAMPLES: THE AUTOINFLAMMATORY BONE CONDITION CHRONIC NONBACTERIAL OSTEOMYELITIS (CNO), THE "MIXED PATTERN" DISORDER PSORIASIS, AND THE AUTOIMMUNE DISEASE SYSTEMIC LUPUS ERYTHEMATOSUS (SLE). 2019 5 2224 32 EPIGENETIC MODIFICATIONS IN THE PATHOGENESIS OF SYSTEMIC SCLEROSIS. SYSTEMIC SCLEROSIS IS A RARE CHRONIC AUTOIMMUNE DISEASE, WHICH MAINLY MANIFESTS AS IMMUNE DISORDERS, VASCULAR DAMAGE, AND PROGRESSIVE FIBROSIS. THE ETIOLOGY OF SSC IS COMPLEX AND INVOLVES MULTIPLE FACTORS. BOTH GENETIC AND ENVIRONMENTAL FACTORS ARE INVOLVED IN ITS PATHOGENESIS. AS ONE OF THE MOLECULAR MECHANISMS OF ENVIRONMENTAL FACTORS, EPIGENETIC REGULATION PLAYS AN IMPORTANT ROLE IN THE OCCURRENCE AND DEVELOPMENT OF SYSTEMIC SCLEROSIS, WHICH INVOLVES DNA METHYLATION, HISTONE MODIFICATION AND NON-CODING RNA REGULATION. THIS REVIEW SUMMARIZES RESEARCH ADVANCES IN EPIGENETICS, INCLUDING EXOSOMES, LNCRNA, AND MENTIONS POSSIBLE BIOMARKERS AND THERAPEUTIC TARGETS AMONG THEM. 2022 6 2238 29 EPIGENETIC MODULATION AS A THERAPEUTIC PROSPECT FOR TREATMENT OF AUTOIMMUNE RHEUMATIC DISEASES. SYSTEMIC INFLAMMATORY RHEUMATIC DISEASES ARE CONSIDERED AS AUTOIMMUNE DISEASES, MEANING THAT THE BALANCE BETWEEN RECOGNITION OF PATHOGENS AND AVOIDANCE OF SELF-ATTACK IS IMPAIRED AND THE IMMUNE SYSTEM ATTACKS AND DESTROYS ITS OWN HEALTHY TISSUE. TREATMENT WITH CONVENTIONAL DISEASE MODIFYING ANTIRHEUMATIC DRUGS (DMARDS) AND/OR NONSTEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS) IS OFTEN ASSOCIATED WITH VARIOUS ADVERSE REACTIONS DUE TO UNSPECIFIC AND TOXIC PROPERTIES OF THOSE DRUGS. ALTHOUGH BIOLOGIC DRUGS HAVE LARGELY IMPROVED THE OUTCOME IN MANY PATIENTS, SUCH DRUGS STILL POSE SIGNIFICANT PROBLEMS AND FAIL TO PROVIDE A SOLUTION TO ALL PATIENTS. THEREFORE, DEVELOPMENT OF MORE EFFECTIVE TREATMENTS AND IMPROVEMENTS IN EARLY DIAGNOSIS OF RHEUMATIC DISEASES ARE BADLY NEEDED IN ORDER TO INCREASE PATIENT'S FUNCTIONING AND QUALITY OF LIFE. THE REVERSIBLE NATURE OF EPIGENETIC MECHANISMS OFFERS A NEW CLASS OF DRUGS THAT MODULATE THE IMMUNE SYSTEM AND INFLAMMATION. IN FACT, EPIGENETIC DRUGS ARE ALREADY IN USE IN SOME TYPES OF CANCER OR CARDIOVASCULAR DISEASES. THEREFORE, EPIGENETIC-BASED THERAPEUTICS THAT CONTROL AUTOIMMUNITY AND CHRONIC INFLAMMATORY PROCESS HAVE BROAD IMPLICATIONS FOR THE PATHOGENESIS, DIAGNOSIS, AND MANAGEMENT OF RHEUMATIC DISEASES. THIS REVIEW SUMMARISES THE LATEST INFORMATION ABOUT POTENTIAL THERAPEUTIC APPLICATION OF EPIGENETIC MODIFICATION IN TARGETING IMMUNE ABNORMALITIES AND INFLAMMATION OF RHEUMATIC DISEASES. 2016 7 549 29 AUTOANTIGENS: NOVEL FORMS AND PRESENTATION TO THE IMMUNE SYSTEM. IT IS CLEAR THAT LUPUS AUTOIMMUNITY IS MARKED BY A VARIETY OF ABNORMALITIES, INCLUDING THOSE FOUND AT A MACROSCOPIC SCALE, CELLS AND TISSUES, AS WELL AS MORE MICROENVIRONMENTAL INFLUENCES, ORIGINATING AT THE INDIVIDUAL CELL SURFACE THROUGH TO THE NUCLEUS. THE CONVERGENCE OF GENETIC, EPIGENETIC, AND PERHAPS ENVIRONMENTAL INFLUENCES ALL LEAD TO THE OVERT CLINICAL EXPRESSION OF DISEASE, REFLECTED BY THE PRESENCES OF AUTOANTIBODIES AND TISSUE PATHOLOGY. THIS REVIEW WILL ADDRESS SEVERAL SPECIFIC AREAS THAT FALL AMONG THE NON-GENETIC FACTORS THAT CONTRIBUTE TO LUPUS AUTOIMMUNITY AND RELATED SYNDROMES. IN PARTICULAR, WE WILL DISCUSS THE IMPORTANCE OF UNDERSTANDING VARIOUS PROTEIN POST-TRANSLATIONAL MODIFICATIONS (PTMS), MECHANISMS THAT MEDIATE THE ABILITY OF "MODIFIED SELF" TO TRIGGER AUTOIMMUNITY, AND HOW THESE PTMS INFLUENCE LUPUS DIAGNOSIS. FINALLY, WE WILL DISCUSS ALTERED PATHWAYS OF AUTOANTIGEN PRESENTATION THAT MAY CONTRIBUTE TO THE PERPETUATION OF CHRONIC AUTOIMMUNE DISEASE. 2014 8 4845 31 ONE YEAR IN REVIEW 2020: PATHOGENESIS OF RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC INFLAMMATORY AUTOIMMUNE DISEASE INFLUENCED BY BOTH GENETIC, EPIGENETIC AND ENVIRONMENTAL FACTORS. THE DISCOVERY OF NEW GENE POLYMORPHISMS AND THEIR ASSOCIATION WITH DISEASE SUSCEPTIBILITY HAVE ADDED NEW ELEMENTS TO BETTER CLARIFY RA PATHOGENESIS. IN THE LAST YEAR, IMPORTANT ELEMENTS HAVE BEEN ADDED TO THE CURRENT KNOWLEDGE OF MECHANISMS REGULATING INNATE AND ADAPTIVE IMMUNITY IN RA, LEADING TO DISCOVERING NEW TARGETS FOR THE DEVELOPMENT OF DISEASE-MODIFYING THERAPIES. THUS, IN THIS REVIEW WE SUMMARISE THE NEW INSIGHTS RESULTING FROM A LITERATURE RESEARCH DATA PUBLISHED IN THE LAST YEAR. 2020 9 2027 32 EPIGENETIC CHANGES IN CHRONIC INFLAMMATORY DISEASES. THE NUMBER OF PEOPLE DIAGNOSED WITH CHRONIC INFLAMMATORY DISEASES HAS INCREASED NOTEWORTHY IN THE LAST 40 YEARS. SPONDYLOARTHRITIS (SPA), INFLAMMATORY BOWEL DISEASES (IBD), AND PSORIASIS ARE THE MOST FREQUENT CHRONIC INFLAMMATORY DISEASES, RESULTING FROM A COMBINATION OF GENETIC PREDISPOSITION AND ENVIRONMENTAL FACTORS. EPIGENETIC MODIFICATIONS INCLUDE DNA METHYLATION, HISTONE MODIFICATIONS, AND SMALL AND LONG NONCODING RNAS. THEY ARE INFLUENCED BY ENVIRONMENTAL EXPOSURE, LIFE-STYLE, AND AGING AND HAVE RECENTLY BEEN SHOWN TO BE ALTERED IN MANY COMPLEX DISEASES INCLUDING INFLAMMATORY DISEASES. WHILE EPIGENETIC MODIFICATIONS HAVE BEEN WELL CHARACTERIZED IN OTHER DISEASES SUCH AS CANCER AND AUTOIMMUNE DISEASES, KNOWLEDGE ON CHANGES IN INFLAMMATORY DISEASES IS LAGGING BEHIND WITH SOME DISEASE-SPECIFIC DIFFERENCES. WHILE THE DNA METHYLATION PROFILE OF DIFFERENT CELL TYPES IN PATIENTS WITH IBD HAS BEEN RELATIVELY WELL DESCRIBED, LESS IS KNOWN ON CHANGES IMPLICATED IN PSORIASIS, AND NO SYSTEMATIC GENOME-WIDE STUDIES HAVE SO FAR BEEN PERFORMED IN SPA. IN THIS CHAPTER, WE REVIEW IN DETAIL THE REPORTED CHANGES IN PATTERNS OF DNA METHYLATION AND POSTTRANSLATIONAL HISTONE MODIFICATIONS IN CHRONIC INFLAMMATORY DISEASES HIGHLIGHTING POTENTIAL CONNECTIONS BETWEEN DISEASE-ASSOCIATED PATHOPHYSIOLOGICAL CHANGES SUCH AS THE DYSBIOSIS OF THE MICROBIOME OR GENETIC VARIATIONS ASSOCIATED WITH DISEASE SUSCEPTIBILITY AND THE EPIGENOME. WE ALSO DISCUSS IMPORTANT PARAMETERS OF MEANINGFUL EPIGENETIC STUDIES SUCH AS THE USE OF WELL DEFINED, DISEASE-RELEVANT CELL POPULATIONS, AND ELUDE ON THE POTENTIAL FUTURE OF ENGINEERING OF THE EPIGENOME IN INFLAMMATORY DISEASES. 2017 10 2988 22 GENETIC FACTORS AND SYSTEMIC SCLEROSIS. SYSTEMIC SCLEROSIS (SSC) IS A RARE CONNECTIVE TISSUE DISEASE OF UNKNOWN ETIOLOGY CHARACTERIZED BY CHRONIC INFLAMMATION AND FIBROSIS OF THE SKIN, VASCULAR ABNORMALITIES, AND VARIABLE INVOLVEMENT OF ORGANS INCLUDING KIDNEYS, GASTROINTESTINAL TRACT, HEART, AND LUNGS. SSC SHOWS A COMPLEX ETIOLOGY IN WHICH BOTH ENVIRONMENTAL AND GENETIC FACTORS SEEM TO INFLUENCE THE ONSET AND OUTCOME OF THE DISEASE. WE PROVIDE AN EXTENSIVE OVERVIEW OF THE GENETIC FACTORS AND EPIGENETIC MODIFICATIONS AND WHAT THEIR KNOWLEDGE HAS REVEALED IN TERMS OF ETIOPATHOGENESIS OF SSC. 2016 11 3016 38 GENETICS AND EPIGENETICS OF IBD. INFLAMMATORY BOWEL DISEASES (IBD) ARE CHRONIC INTERMITTENT INFLAMMATORY DISORDERS OF THE GASTROINTESTINAL TRACT OF UNKNOWN ETIOLOGY BUT A CLEAR GENETIC PREDISPOSITION. PROMPTED BY THE FIRST INVESTIGATIONS ON IBD FAMILIES AND TWINS, THE GENETIC AND EPIGENETIC STUDIES HAVE PRODUCED AN UNPRECEDENTED AMOUNT OF INFORMATION IN COMPARISON WITH OTHER IMMUNE-MEDIATED OR COMPLEX DISEASES. NEW INFLAMMATORY PATHWAYS AND POSSIBLE MECHANISMS OF ACTION HAVE BEEN DISCLOSED, POTENTIALLY LEADING TO NEW-TARGETED THERAPY. HOWEVER, THE IDENTIFICATION OF GENETIC MARKERS DUE TO THE GREAT DISEASE HETEROGENEITY AND THE OVERWHELMING CONTRIBUTION OF ENVIRONMENTAL RISK FACTORS HAS NOT MODIFIED YET THE DISEASE MANAGEMENT. THE POSSIBILITY FOR THE FUTURE OF A BETTER PREDICTION OF DISEASE COURSE, RESPONSE TO THERAPY AND THERAPY-RELATED ADVERSE EVENTS MAY ALLOW A MORE EFFICIENT AND PERSONALIZED STRATEGY. THIS REVIEW WILL FOCUS ON MORE RECENT DISCOVERIES THAT MAY POTENTIALLY BE OF RELEVANCE IN DAILY CLINICAL PRACTICE. 2020 12 2591 43 EPIGENETICS OF PSORIASIS. PSORIASIS IS A CHRONIC AND RECURRENT INFLAMMATORY SKIN DISEASE, INVOLVING THE RAPID PROLIFERATION AND ABNORMAL DIFFERENTIATION OF KERATINOCYTES AND ACTIVATION OF T CELLS. IT IS GENERALLY ACCEPTED THAT THE CENTRAL PATHOGENESIS OF PSORIASIS IS A T CELL-DOMINANT IMMUNE DISORDER AFFECTED BY MULTIPLE FACTORS INCLUDING GENETIC SUSCEPTIBILITY, ENVIRONMENTAL FACTORS, INNATE AND ADAPTIVE IMMUNE RESPONSES, ETC. HOWEVER, THE EXACT ETIOLOGY IS LARGELY UNKNOWN. IN RECENT YEARS, EPIGENETIC INVOLVEMENTS, SUCH AS THE DNA METHYLATION, CHROMATIN MODIFICATIONS, AND NONCODING RNA REGULATION ARE REPORTED TO BE CRITICAL FOR THE PATHOGENESIS OF PSORIASIS. HOWEVER, THE INTERPLAY BETWEEN THESE FACTORS HAS ONLY RECENTLY BEEN STARTED TO BE UNRAVELED. NOTABLY, INHIBITORS OF ENZYMES THAT WORK IN EPIGENETIC MODIFICATIONS, SUCH AS DNA METHYLTRANSFERASES AND HISTONE DEACETYLASES, ARE BEGINNING TO APPEAR IN THE CLINICAL SETTING TO RESTORE NORMAL EPIGENETIC PATTERNS (GENERALI ET AL. IN J AUTOIMMUN 83:51-61, 2017), PROVIDING NOVEL THERAPEUTIC POTENTIAL AS NOVEL TREATMENT TARGETS FOR PSORIASIS. INDEED, MEDICATIONS PREVIOUSLY USED TO TREAT AUTOIMMUNE DISEASES HAVE LATER BEEN DISCOVERED TO EXERT THEIR ACTION VIA EPIGENETIC MECHANISMS. HEREIN, WE REVIEW THE FINDINGS ON EPIGENETICS ASSOCIATED WITH PSORIASIS, AND DISCUSS FUTURE PERSPECTIVES IN THIS FIELD. 2020 13 1608 41 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 14 6178 36 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 15 6107 39 THE EMERGING ROLE OF NONCODING RNAS IN SYSTEMIC LUPUS ERYTHEMATOSUS: NEW INSIGHTS INTO THE MASTER REGULATORS OF DISEASE PATHOGENESIS. AUTO-IMMUNE DISEASES ARE A FORM OF CHRONIC DISORDERS IN WHICH THE IMMUNE SYSTEM DESTROYS THE BODY'S CELLS DUE TO A LOSS OF TOLERANCE TO SELF-ANTIGENS. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE), IDENTIFIED BY THE PRODUCTION OF AUTOANTIBODIES IN DIFFERENT BODY PARTS, IS ONE OF THE MOST WELL-KNOWN EXAMPLES OF THESE DISEASES. ALTHOUGH THE ETIOLOGY OF SLE IS UNCLEAR, THE DISEASE'S PROGRESSION MAY BE AFFECTED BY GENETIC AND ENVIRONMENTAL FACTORS. AS STUDIES IN TWINS PROVIDE ADEQUATE EVIDENCE FOR GENETIC INVOLVEMENT IN THE SLE, OTHER PHENOMENA SUCH AS METALLIZATION, HISTONE MODIFICATIONS, AND ALTERATIONS IN THE EXPRESSION OF NONCODING RNAS (NCRNAS) ALSO INDICATE THE INVOLVEMENT OF EPIGENETIC FACTORS IN THIS DISEASE. AMONG ALL THE EPIGENETIC ALTERATIONS, NCRNAS APPEAR TO HAVE THE MOST CRUCIAL CONTRIBUTION TO THE PATHOGENESIS OF SLE. THE NCRNAS' LENGTH AND SIZE ARE DIVIDED INTO THREE MAIN CLASSES: MICRO RNAS, LONG NONCODING RNAS (LNCRNA), AND CIRCULAR RNAS (CIRCRNAS). ACCUMULATING EVIDENCE SUGGESTS THAT DYSREGULATIONS IN THESE NCRNAS CONTRIBUTED TO THE PATHOGENESIS OF SLE. HENCE, CLARIFYING THE FUNCTION OF THESE GROUPS OF NCRNAS IN THE PATHOPHYSIOLOGY OF SLE PROVIDES A DEEPER UNDERSTANDING OF THE DISEASE. IT ALSO OPENS UP NEW OPPORTUNITIES TO DEVELOP TARGETED THERAPIES FOR THIS DISEASE. 2023 16 6194 44 THE IMPACT OF PROTEIN ACETYLATION/DEACETYLATION ON SYSTEMIC LUPUS ERYTHEMATOSUS. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IS A CHRONIC INFLAMMATORY AUTOIMMUNE DISEASE IN WHICH THE BODY'S IMMUNE SYSTEM MISTAKENLY ATTACKS HEALTHY CELLS. ALTHOUGH THE EXACT CAUSE OF SLE HAS NOT BEEN IDENTIFIED, IT IS CLEAR THAT BOTH GENETICS AND ENVIRONMENTAL FACTORS TRIGGER THE DISEASE. IDENTICAL TWINS HAVE A 24% CHANCE OF GETTING LUPUS DISEASE IF THE OTHER ONE IS AFFECTED. INTERNAL FACTORS SUCH AS FEMALE GENDER AND SEX HORMONES, THE MAJOR HISTOCOMPATIBILITY COMPLEX (MHC) LOCUS AND OTHER GENETIC POLYMORPHISMS HAVE BEEN SHOWN TO AFFECT SLE, AS WELL AS EXTERNAL, ENVIRONMENTAL INFLUENCES SUCH AS SUNLIGHT EXPOSURE, SMOKING, VITAMIN D DEFICIENCY, AND CERTAIN INFECTIONS. SEVERAL STUDIES HAVE REPORTED AND PROPOSED MULTIPLE ASSOCIATIONS BETWEEN THE ALTERATION OF THE EPIGENOME AND THE PATHOGENESIS OF AUTOIMMUNE DISEASE. EPIGENETIC FACTORS CONTRIBUTING TO SLE INCLUDE MICRORNAS, DNA METHYLATION STATUS, AND THE ACETYLATION/DEACETYLATION OF HISTONE PROTEINS. ADDITIONALLY, THE ACETYLATION OF NON-HISTONE PROTEINS CAN ALSO INFLUENCE CELLULAR FUNCTION. A BETTER UNDERSTANDING OF NON-GENOMIC FACTORS THAT REGULATE SLE WILL PROVIDE INSIGHT INTO THE MECHANISMS THAT INITIATE AND FACILITATE DISEASE AND ALSO CONTRIBUTE TO THE DEVELOPMENT OF NOVEL THERAPEUTICS THAT CAN SPECIFICALLY TARGET PATHOGENIC MOLECULAR PATHWAYS. 2018 17 4883 35 OVERVIEW OF THE MOLECULAR DETERMINANTS CONTRIBUTING TO THE EXPRESSION OF PSORIASIS AND PSORIATIC ARTHRITIS PHENOTYPES. PSORIASIS AND PSORIATIC ARTHRITIS ARE MULTIFACTORIAL CHRONIC DISORDERS WHOSE ETIOPATHOGENESIS ESSENTIALLY DERIVES FROM THE ALTERATION OF SEVERAL SIGNALLING PATHWAYS AND THE CO-OCCURRENCE OF GENETIC, EPIGENETIC AND NON-GENETIC SUSCEPTIBILITY FACTORS THAT ALTOGETHER AFFECT THE FUNCTIONAL AND STRUCTURAL PROPERTY OF THE SKIN. ALTHOUGH SHARED AND DIFFERENTIAL SUSCEPTIBILITY GENES AND MOLECULAR PATHWAYS ARE KNOWN TO CONTRIBUTE TO THE ONSET OF PATHOLOGICAL PHENOTYPES, FURTHER RESEARCH IS NEEDED TO DISSECT THE MOLECULAR CAUSES OF PSORIATIC DISEASE AND ITS PROGRESSION TOWARDS PSORIATIC ARTHRITIS. THIS REVIEW WILL THEREFORE BE ADDRESSED TO EXPLORE DIFFERENCES AND SIMILARITIES IN THE ETIOPATHOGENESIS AND PROGRESSION OF BOTH DISORDERS, WITH A PARTICULAR FOCUS ON GENES INVOLVED IN THE MAINTENANCE OF THE SKIN STRUCTURE AND INTEGRITY (KERATINS AND COLLAGENS), MODULATION OF PATTERNS OF RECOGNITION (THROUGH TOLL-LIKE RECEPTORS AND DECTIN-1) AND IMMUNO-INFLAMMATORY RESPONSE (BY NLRP3-DEPENDENT INFLAMMASOME) TO MICROBIAL PATHOGENS. IN ADDITION, SPECIAL EMPHASIS WILL BE GIVEN TO THE CONTRIBUTION OF EPIGENETIC ELEMENTS (METHYLATION PATTERN, NON-CODING RNAS, CHROMATIN MODIFIERS AND 3D GENOME ORGANIZATION) TO THE ETIOPATHOGENESIS AND PROGRESSION OF PSORIASIS AND PSORIATIC ARTHRITIS. THE EVIDENCE DISCUSSED IN THIS REVIEW HIGHLIGHTS HOW THE KNOWLEDGE OF PATIENTS' CLINICAL AND (EPI)GENOMIC MAKE-UP COULD BE HELPFUL FOR IMPROVING THE AVAILABLE THERAPEUTIC STRATEGIES FOR PSORIASIS AND PSORIATIC ARTHRITIS TREATMENT. 2020 18 1812 37 EFFECTS OF BIOLOGICAL THERAPIES ON MOLECULAR FEATURES OF RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS (RA) IS AN AUTOIMMUNE AND CHRONIC INFLAMMATORY DISEASE PRIMARILY AFFECTING THE JOINTS, AND CLOSELY RELATED TO SPECIFIC AUTOANTIBODIES THAT MOSTLY TARGET MODIFIED SELF-EPITOPES. RELEVANT FINDINGS IN THE FIELD OF RA PATHOGENESIS HAVE BEEN DESCRIBED. IN PARTICULAR, NEW INSIGHTS COME FROM STUDIES ON SYNOVIAL FIBROBLASTS AND CELLS BELONGING TO THE INNATE AND ADAPTIVE IMMUNE SYSTEM, WHICH DOCUMENTED THE ABERRANT PRODUCTION OF INFLAMMATORY MEDIATORS, OXIDATIVE STRESS AND NETOSIS, ALONG WITH RELEVANT ALTERATIONS OF THE GENOME AND ON THE REGULATORY EPIGENETIC MECHANISMS. IN RECENT YEARS, THE ADVANCES IN THE UNDERSTANDING OF RA PATHOGENESIS BY IDENTIFYING KEY CELLS AND CYTOKINES ALLOWED THE DEVELOPMENT OF NEW TARGETED DISEASE-MODIFYING ANTIRHEUMATIC DRUGS (DMARDS). THESE DRUGS CONSIDERABLY IMPROVED TREATMENT OUTCOMES FOR THE MAJORITY OF PATIENTS. MOREOVER, NUMEROUS STUDIES DEMONSTRATED THAT THE PHARMACOLOGICAL THERAPY WITH BIOLOGIC DMARDS (BDMARDS) PROMOTES, IN PARALLEL TO THEIR CLINICAL EFFICACY, SIGNIFICANT IMPROVEMENT IN ALL THESE ALTERED MOLECULAR MECHANISMS. THUS, CONTINUOUS UPDATING OF THE KNOWLEDGE OF MOLECULAR PROCESSES ASSOCIATED WITH THE PATHOGENESIS OF RA, AND ON THE SPECIFIC EFFECTS OF BDMARDS IN THE CORRECTION OF THEIR DYSREGULATION, ARE ESSENTIAL IN THE EARLY AND CORRECT APPROACH TO THE TREATMENT OF THIS COMPLEX AUTOIMMUNE DISORDER. THE PRESENT REVIEW DETAILS BASIC MECHANISMS RELATED TO THE PHYSIOPATHOLOGY OF RA, ALONG WITH THE CORE MECHANISMS OF RESPONSE TO BDMARDS. 2020 19 6255 34 THE MICROBIOTA AND EPIGENETIC REGULATION OF T HELPER 17/REGULATORY T CELLS: IN SEARCH OF A BALANCED IMMUNE SYSTEM. IMMUNE CELLS NOT ONLY AFFECT TISSUE HOMEOSTASIS AT THE SITE OF INFLAMMATION BUT ALSO EXERT SYSTEMIC EFFECTS CONTRIBUTING TO MULTIPLE CHRONIC CONDITIONS. RECENT EVIDENCE CLEARLY SUPPORTS AN ALTERED T HELPER 17/REGULATORY T CELL (TH17/TREG) BALANCE LEADING TO THE DEVELOPMENT AND PROGRESSION OF INFLAMMATORY DISEASES THAT NOT ONLY AFFECT THE GASTROINTESTINAL TRACT BUT ALSO HAVE WHOLE-BODY MANIFESTATIONS, INCLUDING INSULIN RESISTANCE. EPIGENETIC MECHANISMS ARE AMENABLE TO BOTH ENVIRONMENTAL AND CIRCULATING FACTORS AND CONTRIBUTE TO DETERMINING THE T CELL LANDSCAPE. THE RECENTLY IDENTIFIED PARTICIPATION OF THE GUT MICROBIOTA IN THE REMODELING OF THE EPIGENOME OF IMMUNE CELLS HAS TRIGGERED A PARADIGM SHIFT IN OUR UNDERSTANDING OF THE ETIOLOGY OF VARIOUS INFLAMMATORY DISEASES AND OPENED NEW PATHS TOWARD THERAPEUTIC STRATEGIES. IN THIS REVIEW, WE PROVIDE AN OVERVIEW OF THE CONTRIBUTION OF THE TH17/TREG BALANCE IN THE DEVELOPMENT AND PROGRESSION OF INFLAMMATORY BOWEL DISEASES AND METABOLIC DISEASES. WE DISCUSS THE INVOLVEMENT OF EPIGENETIC MECHANISMS IN THE REGULATION OF T CELL FUNCTION IN THE PARTICULAR CONTEXT OF DYSBIOSIS. FINALLY, WE EXAMINE THE POTENTIAL FOR NUTRITIONAL INTERVENTIONS AFFECTING THE GUT MICROBIOTA TO RESHAPE THE T CELL EPIGENOME AND ADDRESS THE INFLAMMATORY COMPONENT OF VARIOUS DISEASES. 2017 20 2569 34 EPIGENETICS OF ANKYLOSING SPONDYLITIS: RECENT DEVELOPMENTS. ANKYLOSING SPONDYLITIS (AS) IS A CHRONIC INFLAMMATORY AUTOIMMUNE DISEASE WHICH MAINLY AFFECTS THE SPINE, SACROILIAC JOINT AND PERIPHERAL JOINTS. TO DATE, THE EXACT CAUSES AND PATHOGENESIS OF AS STILL REMAIN UNKNOWN. IT IS CONSIDERED THAT THE PATHOGENESIS OF AS IS ASSOCIATED WITH GENETIC, INFECTION, ENVIRONMENT, IMMUNITY AND OTHER FACTORS. AMONG THEM, THE ROLE OF GENETIC FACTORS IN THE PATHOGENESIS OF AS HAS BEEN STUDIED MOST DEEPLY. HOWEVER, OVER THE PAST FEW YEARS, THE FUNCTION OF ENVIRONMENTAL PREDISPOSITION AND EPIGENETIC MODIFICATION IN THE PATHOGENESIS OF AS HAS RECEIVED EXTENSIVE ATTENTION. THIS PAPER SUMMARIZES THE RECENT PROGRESS IN THE EPIGENETICS OF AS, INCLUDING ABNORMAL EPIGENETIC MODIFICATIONS AT AS-ASSOCIATED GENOMIC LOCI, SUCH AS DNA METHYLATION, HISTONE MODIFICATION, MICRORNA, AND SO ON. IN SUMMARY, THE FINDINGS OF THIS REVIEW ATTEMPT TO EXPLAIN THE ROLE OF EPIGENETIC MODIFICATION IN THE OCCURRENCE AND DEVELOPMENT OF AS. NEVERTHELESS, THERE ARE STILL UNKNOWN AND COMPLICATED ASPECTS WORTH EXPLORING TO DEEPEN OUR UNDERSTANDING OF THE PATHOGENESIS OF AS. 2021