1 2516 143 EPIGENETICS AND SYSTEMIC LUPUS ERYTHEMATOSUS: UNMET NEEDS. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IS A CHRONIC RELAPSING-REMITTING AUTOIMMUNE DISEASE AFFECTING SEVERAL ORGANS. ALTHOUGH THE MANAGEMENT OF LUPUS PATIENTS HAS IMPROVED IN THE LAST YEARS, SEVERAL ASPECTS STILL REMAIN CHALLENGING. MORE SENSITIVE AND SPECIFIC BIOMARKERS FOR AN EARLY DIAGNOSIS AS WELL AS FOR MONITORING DISEASE ACTIVITY AND TISSUE DAMAGE ARE NEEDED. GENOME-WIDE ASSOCIATION AND GENE MAPPING STUDIES HAVE SUPPORTED THE GENETIC BACKGROUND FOR SLE SUSCEPTIBILITY. HOWEVER, THE RELATIVELY MODEST RISK ASSOCIATION AND THE STUDIES IN TWINS HAVE SUGGESTED A ROLE FOR ENVIRONMENTAL AND EPIGENETIC FACTORS, AS WELL AS GENETIC-EPIGENETIC INTERACTION. ACCORDINGLY, THERE IS EVIDENCE THAT DIFFERENCES IN DNA METHYLATION, HISTONE MODIFICATIONS, AND MIRNA PROFILING CAN BE FOUND IN LUPUS PATIENTS VERSUS NORMAL SUBJECTS. MOREOVER, IMPAIRED DNA METHYLATION ON THE INACTIVE X-CHROMOSOME WAS SUGGESTED TO EXPLAIN, AT LEAST IN PART, THE FEMALE PREVALENCE OF THE DISEASE. EPIGENETIC MARKERS MAY BE HELP IN FULFILLING THE UNMET NEEDS FOR SLE BY OFFERING NEW DIAGNOSTIC TOOLS, NEW BIOMARKERS FOR MONITORING DISEASE ACTIVITY, OR TO BETTER CHARACTERIZE PATIENTS WITH A SILENT CLINICAL DISEASE BUT WITH AN ACTIVE SEROLOGY. ANTI-DNA, ANTI-PHOSPHOLIPID, AND ANTI-RO/SSA AUTOANTIBODIES ARE THOUGHT TO BE PATHOGENIC FOR GLOMERULONEPHRITIS, RECURRENT THROMBOSIS AND MISCARRIAGES, AND NEONATAL LUPUS, RESPECTIVELY. HOWEVER, TISSUE DAMAGE OCCURS OCCASIONALLY OR, IN SOME PATIENTS, ONLY IN SPITE OF THE PERSISTENT PRESENCE OF THE ANTIBODIES. PRELIMINARY STUDIES SUGGEST THAT EPIGENETIC MECHANISMS MAY EXPLAIN WHY THE DAMAGE TAKES PLACE IN SOME PATIENTS ONLY OR AT A GIVEN TIME. 2016 2 6194 38 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 3 1463 42 DISSECTING COMPLEX EPIGENETIC ALTERATIONS IN HUMAN LUPUS. SYSTEMIC LUPUS ERYTHEMATOSUS IS A CHRONIC RELAPSING AUTOIMMUNE DISEASE THAT PRIMARILY AFFLICTS WOMEN, AND BOTH A GENETIC PREDISPOSITION AND APPROPRIATE ENVIRONMENTAL EXPOSURES ARE REQUIRED FOR LUPUS TO DEVELOP AND FLARE. THE GENETIC REQUIREMENT IS EVIDENCED BY AN INCREASED CONCORDANCE IN IDENTICAL TWINS AND BY THE VALIDATION OF AT LEAST 35 SINGLE-NUCLEOTIDE POLYMORPHISMS PREDISPOSING PATIENTS TO LUPUS. GENES ALONE, THOUGH, ARE NOT ENOUGH. THE CONCORDANCE OF LUPUS IN IDENTICAL TWINS IS OFTEN INCOMPLETE, AND WHEN CONCORDANT, THE AGE OF ONSET IS USUALLY DIFFERENT. LUPUS IS ALSO NOT PRESENT AT BIRTH, BUT ONCE THE DISEASE DEVELOPS, IT TYPICALLY FOLLOWS A CHRONIC RELAPSING COURSE. THUS, GENES ALONE ARE INSUFFICIENT TO CAUSE HUMAN LUPUS, AND ADDITIONAL FACTORS ENCOUNTERED IN THE ENVIRONMENT AND OVER TIME ARE REQUIRED TO INITIATE THE DISEASE AND SUBSEQUENT FLARES. THE NATURE OF THE ENVIRONMENTAL CONTRIBUTION, THOUGH, AND THE MECHANISMS BY WHICH ENVIRONMENTAL AGENTS MODIFY THE IMMUNE RESPONSE TO CAUSE LUPUS ONSET AND FLARES IN GENETICALLY PREDISPOSED PEOPLE HAVE BEEN CONTROVERSIAL. REPORTS THAT THE LUPUS-INDUCING DRUGS PROCAINAMIDE AND HYDRALAZINE ARE EPIGENETIC MODIFIERS, THAT EPIGENETICALLY MODIFIED T CELLS ARE SUFFICIENT TO CAUSE LUPUS-LIKE AUTOIMMUNITY IN ANIMAL MODELS, AND THAT PATIENTS WITH ACTIVE LUPUS HAVE EPIGENETIC CHANGES SIMILAR TO THOSE CAUSED BY PROCAINAMIDE AND HYDRALAZINE HAVE PROMPTED A GROWING INTEREST IN HOW EPIGENETIC ALTERATIONS CONTRIBUTE TO THIS DISEASE. UNDERSTANDING HOW EPIGENETIC MECHANISMS MODIFY T CELLS TO CONTRIBUTE TO LUPUS REQUIRES AN UNDERSTANDING OF HOW EPIGENETIC MECHANISMS REGULATE GENE EXPRESSION. THE ROLES OF DNA METHYLATION, HISTONE MODIFICATIONS, AND MICRORNAS IN LUPUS PATHOGENESIS WILL BE REVIEWED HERE. 2013 4 398 38 AN UPDATE ON GENETIC SUSCEPTIBILITY IN LUPUS NEPHRITIS. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IS A CHRONIC AUTOIMMUNE DISEASE CHARACTERIZED BY MULTIPLE SYSTEM INVOLVEMENT AND POSITIVE SERUM AUTOANTIBODIES. LUPUS NEPHRITIS (LN) IS THE MOST COMMON AND SERIOUS COMPLICATION OF SLE, AND IT IS THE MAIN CAUSE OF DEATH IN PATIENTS WITH SLE. ABNORMALITIES IN THE IMMUNE SYSTEM LEAD TO LN AND INVOLVE A VARIETY OF CELLS (T CELLS, B CELLS, MACROPHAGES, NK CELLS, ETC.), CYTOKINES (INTERLEUKIN, TUMOR NECROSIS FACTOR ALPHA, ETC.) AND THEIR RELATED PATHWAYS. PREVIOUS STUDIES HAVE SHOWN THAT THE INTERACTIONS OF GENETIC, EPIGENETIC AND ENVIRONMENTAL FACTORS CONTRIBUTE TO THE PATHOGENESIS AND DEVELOPMENT OF LN. IN RECENT YEARS, ONE GENOME-WIDE ASSOCIATION STUDY (GWAS) AND A NUMBER OF GENE ASSOCIATION STUDIES HAVE EXPLORED THE SUSCEPTIBILITY GENES OF LN, INCLUDING IMMUNIZATION-, INFLAMMATION-, ADHESION- AND OTHER PATHWAY-RELATED GENES. THESE GENES PARTICIPATE IN OR SUGGEST THE PATHOGENESIS AND PROGRESSION OF LN. IN THIS REVIEW, WE SUMMARIZE THE GENETIC SUSCEPTIBILITY OF LN AND DISCUSS THE POSSIBLE MECHANISM UNDERLYING THE SUSCEPTIBILITY GENES OF LN. 2020 5 1719 41 DYSREGULATED MICRORNAS IN THE PATHOGENESIS OF SYSTEMIC LUPUS ERYTHEMATOSUS: A COMPREHENSIVE REVIEW. SYSTEMIC LUPUS ERYTHEMATOSUS IS A CHRONIC AUTOIMMUNE DISEASE OF WHICH CLINICAL PRESENTATION IS VASTLY HETEROGENEOUS, RANGING FROM MILD SKIN RASHES TO SEVERE RENAL DISEASES. TREATMENT GOAL OF THIS ILLNESS IS TO MINIMIZE DISEASE ACTIVITY AND PREVENT FURTHER ORGAN DAMAGE. IN RECENT YEARS, MUCH RESEARCH HAS BEEN DONE ON THE EPIGENETIC ASPECTS OF SLE PATHOGENESIS, FOR AMONG THE VARIOUS FACTORS KNOWN TO CONTRIBUTE TO THE PATHOGENIC PROCESS, EPIGENETIC FACTORS, ESPECIALLY MICRORNAS, BEAR THE MOST THERAPEUTIC POTENTIAL THAT CAN BE ALTERED UNLIKE CONGENITAL GENETIC FACTORS. THIS ARTICLE REVIEWS AND UPDATES WHAT HAS BEEN DISCOVERED SO FAR ABOUT THE PATHOGENESIS OF LUPUS, WHILE FOCUSING ON THE DYSREGULATION OF MICRORNAS IN LUPUS PATIENTS IN COMPARISON TO HEALTHY CONTROLS ALONG WITH THE POTENTIALLY PATHOGENIC ROLES OF THE MICRORNAS COMMONLY REPORTED TO BE EITHER UPREGULATED OR DOWNREGULATED. FURTHERMORE, THIS REVIEW INCLUDES MICRORNAS OF WHICH RESULTS ARE CONTROVERSIAL, SUGGESTING POSSIBLE EXPLANATIONS FOR SUCH DISCREPANCIES AND DIRECTIONS FOR FUTURE RESEARCH. MOREOVER, WE AIMED TO EMPHASIZE THE POINT THAT HAD BEEN OVERLOOKED SO FAR IN STUDIES REGARDING MICRORNA EXPRESSION LEVELS; THAT IS, WHICH SPECIMEN WAS USED TO ASSESS THE DYSREGULATION OF MICRORNAS. TO OUR SURPRISE, A VAST NUMBER OF STUDIES HAVE NOT CONSIDERED THIS FACTOR AND HAVE ANALYZED THE POTENTIAL ROLE OF MICRORNAS IN GENERAL. DESPITE EXTENSIVE INVESTIGATIONS DONE ON MICRORNA LEVELS, THEIR SIGNIFICANCE AND POTENTIAL ROLE REMAIN A MYSTERY, WHICH CALLS FOR FURTHER STUDIES ON THIS PARTICULAR SUBJECT IN REGARD OF WHICH SPECIMEN IS USED FOR ASSESSMENT. 2023 6 6275 48 THE PATHOGENESIS OF SYSTEMIC LUPUS ERYTHEMATOSUS: HARNESSING BIG DATA TO UNDERSTAND THE MOLECULAR BASIS OF LUPUS. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IS A CHRONIC, SYSTEMIC AUTOIMMUNE DISEASE THAT CAUSES DAMAGE TO MULTIPLE ORGAN SYSTEMS. DESPITE DECADES OF RESEARCH AND AVAILABLE MURINE MODELS THAT CAPTURE SOME ASPECTS OF THE HUMAN DISEASE, NEW TREATMENTS FOR SLE LAG BEHIND OTHER AUTOIMMUNE DISEASES SUCH AS RHEUMATOID ARTHRITIS AND CROHN'S DISEASE. BIG DATA GENOMIC ASSAYS HAVE TRANSFORMED OUR UNDERSTANDING OF SLE BY PROVIDING IMPORTANT INSIGHTS INTO THE MOLECULAR HETEROGENEITY OF THIS MULTIGENIC DISEASE. GENE WIDE ASSOCIATION STUDIES HAVE DEMONSTRATED MORE THAN 100 RISK LOCI, SUPPORTING A MODEL OF MULTIPLE GENETIC HITS INCREASING SLE RISK IN A NON-LINEAR FASHION, AND PROVIDING EVIDENCE OF ANCESTRAL DIVERSITY IN SUSCEPTIBILITY LOCI. EPIGENETIC STUDIES TO DETERMINE THE ROLE OF METHYLATION, ACETYLATION AND NON-CODING RNAS HAVE PROVIDED NEW UNDERSTANDING OF THE MODULATION OF GENE EXPRESSION IN SLE PATIENTS AND IDENTIFIED NEW DRUG TARGETS AND BIOMARKERS FOR SLE. GENE EXPRESSION PROFILING HAS LED TO A GREATER UNDERSTANDING OF THE ROLE OF MYELOID CELLS IN THE PATHOGENESIS OF SLE, CONFIRMED ROLES FOR T AND B CELLS IN SLE, PROMOTED CLINICAL TRIALS BASED ON THE PROMINENT INTERFERON SIGNATURE FOUND IN SLE PATIENTS, AND IDENTIFIED CANDIDATE BIOMARKERS AND CELLULAR SIGNATURES TO FURTHER DRUG DEVELOPMENT AND DRUG REPURPOSING. GENE EXPRESSION STUDIES ARE ADVANCING OUR UNDERSTANDING OF THE UNDERLYING MOLECULAR HETEROGENEITY IN SLE AND PROVIDING HOPE THAT PATIENT STRATIFICATION WILL EXPEDITE NEW THERAPIES BASED ON PERSONAL MOLECULAR SIGNATURES. ALTHOUGH BIG DATA ANALYSES PRESENT UNIQUE INTERPRETATION CHALLENGES, BOTH COMPUTATIONALLY AND BIOLOGICALLY, ADVANCES IN MACHINE LEARNING APPLICATIONS MAY FACILITATE THE ABILITY TO PREDICT CHANGES IN SLE DISEASE ACTIVITY AND OPTIMIZE THERAPEUTIC STRATEGIES. 2020 7 6791 35 [DOES THE NUMBER OF PATIENTS WITH AUTOIMMUNE DISORDERS AND THE FREQUENCY OF AUTOIMMUNE DISEASES INCREASE?]. AUTOIMMUNE DISEASES GENERALLY BELONG TO THE RARE DISEASES, HOWEVER, SOME OF THEM ARE FREQUENT IN THE POPULATION. IN THE PRESENT WORK THE AUTHORS ANALYSE WHETHER CAN ANY INCREASE BE OBSERVED IN THE NUMBER OF PATIENTS SUFFERING FROM AUTOIMMUNE DISEASES AND WHETHER DO THE FREQUENCY OF CERTAIN AUTOIMMUNE DISORDERS INCREASE. DUE MAINLY TO EPIGENETIC FACTORS THE INCIDENCE OF AUTOIMMUNE DISEASES ARE INCREASING, THEREFORE THERE ARE MORE PATIENTS RECOGNISED WITH PARTICULAR DISORDERS. ON THE OTHER HAND THE INCIDENCE IS INCREASED BY IMPROVING DIAGNOSTIC POSSIBILITIES, BY THE USE OF MORE SPECIFIC AND SENSITIVE CLASSIFICATION CRITERIA AND MORE SOPHISTICATED LABORATORY TESTS, RESULTED IN THE RECOGNITION OF MILDER AND ATYPICAL DISEASE VARIANTS AS WELL. THE PREVALENCE IS ALSO INCREASING IN CONSEQUENCE OF NOVEL IMMUNE SUPPRESSIVE THERAPEUTIC POSSIBILITIES AND THE CONSEQUENT IMPROVEMENT OF SURVIVAL IN THE MOST OF THESE DISEASES. BESIDES, MORE AND MORE DISEASES HAVE BEEN REVEALED TO HAVE AUTOIMMUNE BACKGROUND, AND LOT OF NEW AUTOIMMUNE SYNDROMES, DISEASES HAVE BEEN CHARACTERISED RECENTLY. THIS INCREASES THE NUMBER OF THE KNOWN AUTOIMMUNE RHEUMATIC DISORDERS WITH A CONSEQUENT INCREASE IN THE NUMBER OF AUTOIMMUNE PATIENTS. ASSIGNED TO THE INCREASING NUMBER OF VARIABLE CHRONIC AUTOIMMUNE DISORDERS, AND THE INCREASING NUMBER OF DISABLED PATIENTS WITH SUCH DISEASES INCREASING MEDICAL AND SOCIAL ATTENTION HAS TO BE FOCUSED ON. 2007 8 2017 43 EPIGENETIC BIOMARKERS IN RHEUMATOLOGY - THE FUTURE? EPIGENETIC CHANGES ARE STABLE MODIFICATIONS OF DNA OR HISTONES THAT PROFOUNDLY ALTER GENE EXPRESSION. THEY CAN BE CHANGED BY ENVIRONMENTAL INFLUENCES AND CAN THEN BE PASSED ON TO DAUGHTER CELLS OR VIA THE GERM LINE TO OFFSPRING. A VARIETY OF CHANGES IN EPIGENETIC MARKS AND IN THE EXPRESSION OF NONCODING RNA HAS BEEN FOUND IN CANCER AS WELL AS IN CHRONIC INFLAMMATORY DISEASES. INTERESTINGLY, IN BOTH DISEASES SIMILAR MECHANISMS AND PATHWAYS ARE AFFECTED ALBEIT OFTEN TO A DIFFERENT EXTENT. DNA METHYLATION IS OFTEN LOST IN REPETITIVE SEQUENCES, WHILE IN PROMOTER REGIONS HYPO- AS WELL AS HYPERMETHYLATION IS FOUND. CHANGES IN MICRORNA LEVELS TYPICALLY AFFECT MICRORNAS THAT ARE CHANGED BY AN INFLAMMATORY ENVIRONMENT, BUT DISEASE SPECIFIC CHANGES HAVE ALSO BEEN FOUND IN THE BLOOD AND VARIOUS CELL TYPES OF PATIENTS WITH RHEUMATOID ARTHRITIS, SYSTEMIC LUPUS ERYTHEMATOSUS AND OTHER RHEUMATIC DISEASES. THEREFORE, CHANGES IN THE EXPRESSION OF MICRORNA IN PARTICULAR, BUT ALSO DEMETHYLATED GENE LOCI, HAVE BEEN PROPOSED AS POTENTIAL BIOMARKERS IN CHRONIC INFLAMMATORY DISEASES AND IN CANCER. POTENTIALLY, THESE CHANGES COULD BE USED FOR EARLY DIAGNOSIS AND ALSO TO PREDICT TREATMENT RESPONSE. UNFORTUNATELY MOST STUDIES IN RHEUMATOLOGY UP TO NOW WERE NOT DESIGNED TO VALIDATE THESE EPIGENETIC CHANGES AS BIOMARKERS. SINCE THE CANCER FIELD IS MUCH MORE ADVANCED IN THE USAGE OF BIOMARKERS FOR DISEASE SUBCLASSIFICATIONS AND SUBSEQUENT THERAPEUTIC DECISIONS, IT IS WORTHWHILE TO TAKE A CLOSER LOOK AT THE BIOMARKERS, METHODS AND PROCEDURES USED IN ONCOLOGY AND TO SEE WHICH OF THESE COULD ALSO BE APPLIED TO PREDICTING DISEASE SEVERITY AND THERAPEUTIC RESPONSE IN RHEUMATIC DISEASES. THIS ARTICLE WILL HIGHLIGHT COMMON EPIGENETIC PATHWAYS ACTIVATED IN CANCER AND VARIOUS RHEUMATIC DISEASES AND SUMMARISE EPIGENETIC CHANGES THAT HAVE THE POTENTIAL TO BECOME BIOMARKERS IN RHEUMATIC DISEASES. 2016 9 6262 51 THE MULTIFACETED FUNCTIONAL ROLE OF DNA METHYLATION IN IMMUNE-MEDIATED RHEUMATIC DISEASES. GENOMIC PREDISPOSITION CANNOT EXPLAIN THE ONSET OF COMPLEX DISEASES, AS WELL ILLUSTRATED BY THE LARGELY INCOMPLETE CONCORDANCE AMONG MONOZYGOTIC TWINS. EPIGENETIC MECHANISMS, INCLUDING DNA METHYLATION, CHROMATIN REMODELLING AND NON-CODING RNA, ARE CONSIDERED TO BE THE LINK BETWEEN ENVIRONMENTAL STIMULI AND DISEASE ONSET ON A PERMISSIVE GENETIC BACKGROUND IN AUTOIMMUNE AND CHRONIC INFLAMMATORY DISEASES. THE PARADIGMATIC CASES OF RHEUMATOID ARTHRITIS (RA), SYSTEMIC LUPUS ERYTHEMATOSUS (SLE), SYSTEMIC SCLEROSIS (SSC), SJOGREN'S SYNDROME (SJS) AND TYPE-1 DIABETES (T1D) SHARE THE LOSS OF IMMUNOLOGICAL TOLERANCE TO SELF-ANTIGEN INFLUENCED BY SEVERAL FACTORS, WITH A LARGELY INCOMPLETE ROLE OF INDIVIDUAL GENOMIC SUSCEPTIBILITY. THE MOST WIDELY INVESTIGATED EPIGENETIC MECHANISM IS DNA METHYLATION WHICH IS ASSOCIATED WITH GENE SILENCING AND IS DUE TO THE BINDING OF METHYL-CPG BINDING DOMAIN (MBD)-CONTAINING PROTEINS, SUCH AS MECP2, TO 5-METHYLCYTOSINE (5MC). INDEED, A CAUSAL RELATIONSHIP OCCURS BETWEEN DNA METHYLATION AND TRANSCRIPTION FACTORS OCCUPANCY AND RECRUITMENT AT SPECIFIC GENOMIC LOCUS. IN MOST CASES, THE RESULTS OBTAINED IN DIFFERENT STUDIES ARE CONTROVERSIAL IN TERMS OF DNA METHYLATION COMPARISON WHILE FASCINATING EVIDENCE COMES FROM THE COMPARISON OF THE EPIGENOME IN CLINICALLY DISCORDANT MONOZYGOTIC TWINS. IN THIS MANUSCRIPT, WE WILL REVIEW THE MECHANISMS OF EPIGENETICS AND DNA METHYLATION CHANGES IN SPECIFIC IMMUNE-MEDIATED RHEUMATIC DISEASES TO HIGHLIGHT REMAINING UNMET NEEDS AND TO IDENTIFY POSSIBLE SHARED MECHANISMS BEYOND DIFFERENT TISSUE INVOLVEMENTS WITH COMMON THERAPEUTIC OPPORTUNITIES. KEY POINTS * DNA METHYLATION HAS A CRUCIAL ROLE IN REGULATING AND TUNING THE IMMUNE SYSTEM. * EVIDENCES SUGGEST THAT DYSREGULATION OF DNA METHYLATION IS PIVOTAL IN THE CONTEXT OF IMMUNE-MEDIATED RHEUMATIC DISEASES. * DNA METHYLATION DYSREGULATION IN FOXP3 AND INTERFERONS-RELATED GENES IS SHARED WITHIN SEVERAL AUTOIMMUNE DISEASES. * DNA METHYLATION IS AN ATTRACTIVE MARKER FOR DIAGNOSIS AND THERAPY. 2021 10 6800 47 [EPIGENETIC DISTURBANCES IN SYSTEMIC LUPUS ERYTHEMATOSUS]. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IS A CHRONIC INFLAMMATORY AUTOIMMUNE DISEASE THAT RESULTS IN UNCONTROLLED IMMUNE SYSTEM ACTIVATION AND OVERPRODUCTION OF AUTOANTIBODIES. THE PATHOGENESIS OF THE DISEASE IS COMPLEX AND NOT FULLY UNDERSTOOD, NEVERTHELESS, GENETIC AND ENVIRONMENTAL FACTORS PLAY AN IMPORTANT ROLE. SO FAR, ABOUT 30 GENES HAVE BEEN IDENTIFIED TO BE INVOLVED IN THE SLE PATHOMECHANISM. HOWEVER, NOT ALL GENETICALLY PREDISPOSED INDIVIDUALS DEVELOP THE DISEASE. THIS PHENOMENON CAN BE ASSOCIATED WITH EPIGENETIC CHANGES THAT OCCUR UNDER THE INFLUENCE OF ENVIRONMENTAL FACTORS. THEY CAN AFFECT GENE EXPRESSION AND ARE POTENTIALLY HEREDITARY, BUT DO NOT LEAD TO CHANGES IN THE NUCLEOTIDE SEQUENCE. EPIGENETIC DYSFUNCTIONS, IDENTIFIED IN THE COURSE OF THE DISEASE, LEAD TO CHANGES IN THE EXPRESSION OF GENES THAT PLAY A KEY ROLE IN MAINTAINING THE BODY'S IMMUNE TOLERANCE. MAJOR MECHANISMS OF EPIGENETIC VARIABILITY ARE: DNA METHYLATION, HISTONE PROTEIN MODIFICATION, NON-CODING RNA EXPRESSION, AS WELL AS GENE IMPRINTING. THE MAJOR EPIGENETIC DYSFUNCTIONS AFFECTING THE PATHOGENESIS OF THE DISEASE ARE GLOBAL HYPOMETHYLATION ON CD4+ T CELLS RESULTING FROM ERK SIGNALING PATHWAY REGULATION, HISTONE HYPOACETYLATION, HISTONE H3 LYSINE METHYLATION, AND REACTIVATION OF INACTIVE CHROMOSOME X. IN LUPUS PATIENTS, VARIOUS EPIGENETIC MECHANISMS INTERACT WITH EACH OTHER, ENHANCING THE EXPRESSION OR SILENCING OF GENES RESPONSIBLE FOR THE PRODUCTION OF PRO-INFLAMMATORY AND ANTI-INFLAMMATORY CYTOKINES AND ACTIVATION OF AUTOREACTIVE B-LYMPHOCYTES. 2018 11 5643 42 SEX AND AUTOIMMUNITY: PROPOSED MECHANISMS OF DISEASE ONSET AND SEVERITY. CHRONIC AUTOIMMUNE DISEASES AFFECT 5-10% OF THE POPULATION WORLDWIDE AND ARE LARGELY PREDOMINANT IN WOMEN. SEX HORMONE CHANGES HAVE BEEN WIDELY INVESTIGATED BASED ON CHANGES IN THE CLINICAL PHENOTYPES OBSERVED DURING PREGNANCY AND MENOPAUSE. IT IS KNOWN THAT FEMALES WITH AUTOIMMUNE DISEASES MANIFEST A HIGHER RATE OF CIRCULATING LEUKOCYTES WITH A SINGLE X CHROMOSOME, AND THERE HAVE BEEN SEVERAL REPORTS ON THE ROLE OF X CHROMOSOME GENE DOSAGE THROUGH INACTIVATION OR DUPLICATION IN AUTOIMMUNITY. HOWEVER, IT IS ALSO IMPORTANT NOT TO OVERLOOK MEN WITH AUTOIMMUNE DISEASES, WHO MIGHT MANIFEST A MORE FREQUENT LOSS OF THE Y CHROMOSOME IN CIRCULATING LEUKOCYTES. AREAS COVERED: IN THE PRESENT REVIEW, WE WILL DISCUSS THE CURRENT EVIDENCE SUPPORTING THE MECHANISMS OF FEMALE PREDOMINANCE IN RHEUMATIC DISEASES, BY DISCUSSING THE ROLE OF REPRODUCTIVE HISTORY, SEX HORMONES AND ABNORMALITIES RELATED TO THEM, CLINICAL DIFFERENCES BETWEEN MALE AND FEMALE PATIENTS, AND EPIGENETIC CHANGES THAT HAVE BEEN EVALUATED THROUGH TWIN STUDIES ON GENETIC AND ENVIRONMENTAL CHANGES IN RHEUMATIC PATIENTS. EXPERT OPINION: THE INFLUENCE OF SEX HORMONES AND CHROMOSOMES ON THE FUNCTION OF THE INNATE AND ADAPTIVE IMMUNE SYSTEMS NEEDS TO BE CLARIFIED, TO BETTER UNDERSTAND THE RISK OF AUTOIMMUNE DISEASES, EARLY DIAGNOSTIC TOOLS, AND THERAPEUTIC RESPONSE. 2019 12 2529 35 EPIGENETICS CHANGES ASSOCIATED TO ENVIRONMENTAL TRIGGERS IN AUTOIMMUNITY. AUTOIMMUNE DISEASES (AIDS) ARE CHRONIC CONDITIONS INITIATED BY THE LOSS OF IMMUNOLOGICAL TOLERANCE TO SELF-ANTIGENS AND REPRESENT A HETEROGENEOUS GROUP OF DISORDERS THAT AFFECT SPECIFIC TARGET ORGANS OR MULTIPLE ORGANS IN DIFFERENT SYSTEMS. WHILE THE PATHOGENESIS OF AID REMAINS UNCLEAR, ITS AETIOLOGY IS MULTIFUNCTIONAL AND INCLUDES A COMBINATION OF GENETIC, EPIGENETIC, IMMUNOLOGICAL AND ENVIRONMENTAL FACTORS. IN AIDS, SEVERAL EPIGENETIC MECHANISMS ARE DEFECTIVE INCLUDING DNA DEMETHYLATION, ABNORMAL CHROMATIN POSITIONING ASSOCIATED WITH AUTOANTIBODY PRODUCTION AND ABNORMALITIES IN THE EXPRESSION OF RNA INTERFERENCE (RNAI). IT IS KNOWN THAT ENVIRONMENTAL FACTORS MAY INTERFERE WITH DNA METHYLATION AND HISTONE MODIFICATIONS, HOWEVER, LITTLE IS KNOWN ABOUT EPIGENETIC CHANGES DERIVED OF REGULATION OF RNAI. AN APPROACH TO THE KNOWN ENVIRONMENTAL FACTORS AND THE MECHANISMS THAT ALTER THE EPIGENETIC REGULATION IN AIDS (WITH EMPHASIS IN SYSTEMIC LUPUS ERYTHEMATOSUS, THE PROTOTYPE OF SYSTEMIC AID) ARE SHOWED IN THIS REVIEW. 2016 13 549 31 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 14 4216 48 METHYL DONOR MICRONUTRIENTS: A POTENTIAL DIETARY EPIGENETIC TARGET IN SYSTEMIC LUPUS ERYTHEMATOSUS PATIENTS. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IS A CHRONIC AUTOIMMUNE DISEASE CHARACTERIZED BY AN ABERRANT IMMUNE RESPONSE AND PERSISTENT INFLAMMATION. ITS PATHOGENESIS REMAINS UNKNOWN; HOWEVER, A COMPLEX INTERACTION BETWEEN ENVIRONMENTAL, GENETIC, AND EPIGENETIC FACTORS HAS BEEN SUGGESTED TO CAUSE DISEASE ONSET. SEVERAL STUDIES HAVE DEMONSTRATED THAT EPIGENETIC ALTERATIONS, SUCH AS DNA HYPOMETHYLATION, MIRNA OVEREXPRESSION, AND ALTERED HISTONE ACETYLATION, MAY CONTRIBUTE TO SLE ONSET AND THE DISEASE'S CLINICAL MANIFESTATIONS. EPIGENETIC CHANGES, ESPECIALLY METHYLATION PATTERNS, ARE MODIFIABLE AND SUSCEPTIBLE TO ENVIRONMENTAL FACTORS SUCH AS DIET. IT IS WELL KNOWN THAT METHYL DONOR NUTRIENTS, SUCH AS FOLATE, METHIONINE, CHOLINE, AND SOME B VITAMINS, PLAY A RELEVANT ROLE IN DNA METHYLATION BY PARTICIPATING AS METHYL DONORS OR COENZYMES IN ONE-CARBON METABOLISM. BASED ON THIS KNOWLEDGE, THIS CRITICAL LITERATURE REVIEW AIMED TO INTEGRATE THE EVIDENCE IN ANIMAL MODELS AND HUMANS REGARDING THE ROLE OF NUTRIENTS IN EPIGENETIC HOMEOSTASIS AND THEIR IMPACT ON IMMUNE SYSTEM REGULATION TO SUGGEST A POTENTIAL EPIGENETIC DIET THAT COULD SERVE AS ADJUVANT THERAPY IN SLE. 2023 15 738 33 CANCER SUSCEPTIBILITY: EPIGENETIC MANIFESTATION OF ENVIRONMENTAL EXPOSURES. CANCER IS A DISEASE THAT RESULTS FROM BOTH GENETIC AND EPIGENETIC CHANGES. DISCORDANT PHENOTYPES AND VARYING INCIDENCES OF COMPLEX DISEASES SUCH AS CANCER IN MONOZYGOTIC TWINS AS WELL AS GENETICALLY IDENTICAL LABORATORY ANIMALS HAVE LONG BEEN ATTRIBUTED TO DIFFERENCES IN ENVIRONMENTAL EXPOSURES. ACCUMULATING EVIDENCE INDICATES, HOWEVER, THAT DISPARITIES IN GENE EXPRESSION RESULTING FROM VARIABLE MODIFICATIONS IN DNA METHYLATION AND CHROMATIN STRUCTURE IN RESPONSE TO THE ENVIRONMENT ALSO PLAY A ROLE IN DIFFERENTIAL SUSCEPTIBILITY TO DISEASE. DESPITE A GROWING CONSENSUS ON THE IMPORTANCE OF EPIGENETICS IN THE ETIOLOGY OF CHRONIC HUMAN DISEASES, THE GENES MOST PRONE TO EPIGENETIC DYSREGULATION ARE INCOMPLETELY DEFINED. MOREOVER, NEITHER THE ENVIRONMENTAL AGENTS MOST STRONGLY AFFECTING THE EPIGENOME NOR THE CRITICAL WINDOWS OF VULNERABILITY TO ENVIRONMENTALLY INDUCED EPIGENETIC ALTERATIONS ARE ADEQUATELY CHARACTERIZED. THESE MAJOR DEFICITS IN KNOWLEDGE MARKEDLY IMPAIR OUR ABILITY TO UNDERSTAND FULLY THE ETIOLOGY OF CANCER AND THE IMPORTANCE OF THE EPIGENOME IN DIAGNOSING AND PREVENTING THIS DEVASTATING DISEASE. 2007 16 3038 38 GENOME ENGINEERING FOR OSTEOARTHRITIS: FROM DESIGNER CELLS TO DISEASE-MODIFYING DRUGS. BACKGROUND: OSTEOARTHRITIS (OA) IS A HIGHLY PREVALENT DEGENERATIVE JOINT DISEASE INVOLVING JOINT CARTILAGE AND ITS SURROUNDING TISSUES. OA IS THE LEADING CAUSE OF PAIN AND DISABILITY WORLDWIDE. AT PRESENT, THERE ARE NO DISEASE-MODIFYING OA DRUGS, AND THE PRIMARY THERAPIES INCLUDE EXERCISE AND NONSTEROIDAL ANTI-INFLAMMATORY DRUGS UNTIL TOTAL JOINT REPLACEMENT AT THE END-STAGE OF THE DISEASE. METHODS: IN THIS REVIEW, WE SUMMARIZED THE CURRENT STATE OF KNOWLEDGE IN GENETIC AND EPIGENETIC ASSOCIATIONS AND RISK FACTORS FOR OA AND THEIR POTENTIAL DIAGNOSTIC AND THERAPEUTIC APPLICATIONS. RESULTS: GENOME-WIDE ASSOCIATION STUDIES AND ANALYSIS OF EPIGENETIC MODIFICATIONS (SUCH AS MIRNA EXPRESSION, DNA METHYLATION AND HISTONE MODIFICATIONS) CONDUCTED ACROSS VARIOUS POPULATIONS SUPPORT THE NOTION THAT THERE IS A GENETIC BASIS FOR CERTAIN SUBSETS OF OA PATHOGENESIS. CONCLUSION: WITH RECENT ADVANCES IN THE DEVELOPMENT OF GENOME EDITING TECHNOLOGIES SUCH AS THE CRISPR-CAS9 SYSTEM, THESE GENETIC AND EPIGENETIC ALTERNATIONS IN OA CAN BE USED AS PLATFORMS FROM WHICH POTENTIAL BIOMARKERS FOR THE DIAGNOSIS, PROGNOSIS, DRUG RESPONSE, AND DEVELOPMENT OF POTENTIAL PERSONALIZED THERAPEUTIC TARGETS FOR OA CAN BE APPROACHED. FURTHERMORE, GENOME EDITING HAS ALLOWED THE DEVELOPMENT OF "DESIGNER" CELLS, WHEREBY THE RECEPTORS, GENE REGULATORY NETWORKS, OR TRANSGENES CAN BE MODIFIED AS A BASIS FOR NEW CELL-BASED THERAPIES. 2019 17 5886 38 SYSTEMIC LUPUS ERYTHEMATOSUS. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IS A CHRONIC MULTISYSTEM AUTOIMMUNE DISEASE THAT IS HIGHLY HETEROGENEOUS IN ITS PRESENTATION. THIS CAN POSE SIGNIFICANT CHALLENGES FOR PHYSICIANS RESPONSIBLE FOR THE DIAGNOSIS AND TREATMENT OF SUCH PATIENTS. SLE ARISES FROM A COMBINATION OF GENETIC, EPIGENETIC AND ENVIRONMENTAL FACTORS. PATHOLOGICALLY, THE DISEASE IS PRIMARILY DRIVEN BY LOSS OF IMMUNE TOLERANCE AND ABNORMAL B- AND T-CELL FUNCTION. MAJOR ORGAN INVOLVEMENT MAY LEAD TO SIGNIFICANT MORBIDITY AND MORTALITY. CLASSIFICATION CRITERIA FOR SLE HAVE BEEN DEVELOPED LARGELY FOR RESEARCH PURPOSES; HOWEVER, THESE ARE ALSO WIDELY USED IN CLINICAL PRACTICE. ANTINUCLEAR ANTIBODIES ARE THE HALLMARK SEROLOGICAL FEATURE, OCCURRING IN OVER 95% OF PATIENTS WITH SLE AT SOME POINT DURING THEIR DISEASE. THE MAINSTAY OF TREATMENT IS ANTIMALARIAL DRUGS SUCH AS HYDROXYCHLOROQUINE, COMBINED WITH CORTICOSTEROIDS AND CONVENTIONAL IMMUNOSUPPRESSIVE DRUGS. AN INCREASING UNDERSTANDING OF PATHOGENESIS HAS FACILITATED A MOVE TOWARDS THE DEVELOPMENT OF TARGETED BIOLOGIC THERAPIES, WITH THE INTRODUCTION OF RITUXIMAB AND BELIMUMAB INTO CLINICAL PRACTICE. 2017 18 2404 41 EPIGENETIC RESEARCH IN MULTIPLE SCLEROSIS: PROGRESS, CHALLENGES, AND OPPORTUNITIES. MULTIPLE SCLEROSIS (MS) IS A CHRONIC INFLAMMATORY AND DEMYELINATING DISEASE OF THE CENTRAL NERVOUS SYSTEM. MS LIKELY RESULTS FROM A COMPLEX INTERPLAY BETWEEN PREDISPOSING CAUSAL GENE VARIANTS (THE STRONGEST INFLUENCE COMING FROM HLA CLASS II LOCUS) AND ENVIRONMENTAL RISK FACTORS SUCH AS SMOKING, INFECTIOUS MONONUCLEOSIS, AND LACK OF SUN EXPOSURE/VITAMIN D. HOWEVER, LITTLE IS KNOWN ABOUT THE MECHANISMS UNDERLYING MS DEVELOPMENT AND PROGRESSION. MOREOVER, THE CLINICAL HETEROGENEITY AND VARIABLE RESPONSE TO TREATMENT REPRESENT ADDITIONAL CHALLENGES TO A COMPREHENSIVE UNDERSTANDING AND EFFICIENT TREATMENT OF DISEASE. EPIGENETIC PROCESSES, SUCH AS DNA METHYLATION AND HISTONE POSTTRANSLATIONAL MODIFICATIONS, INTEGRATE INFLUENCES FROM THE GENES AND THE ENVIRONMENT TO REGULATE GENE EXPRESSION ACCORDINGLY. STUDYING EPIGENETIC MODIFICATIONS, WHICH ARE STABLE AND REVERSIBLE, MAY PROVIDE AN ALTERNATIVE APPROACH TO BETTER UNDERSTAND AND MANAGE DISEASE. WE HERE AIM TO REVIEW FINDINGS FROM EPIGENETIC STUDIES IN MS AND FURTHER DISCUSS THE CHALLENGES AND CLINICAL OPPORTUNITIES ARISING FROM EPIGENETIC RESEARCH, MANY OF WHICH APPLY TO OTHER DISEASES WITH SIMILAR COMPLEX ETIOLOGY. A GROWING BODY OF EVIDENCE SUPPORTS A ROLE OF EPIGENETIC PROCESSES IN THE MECHANISMS UNDERLYING IMMUNE PATHOGENESIS AND NERVOUS SYSTEM DYSFUNCTION IN MS. HOWEVER, DISPARITIES BETWEEN STUDIES SHED LIGHT ON THE NEED TO CONSIDER POSSIBLE CONFOUNDERS AND METHODOLOGICAL LIMITATIONS FOR A BETTER INTERPRETATION OF THE DATA. NEVERTHELESS, TRANSLATIONAL USE OF EPIGENETICS MIGHT OFFER NEW OPPORTUNITIES IN EPIGENETIC-BASED DIAGNOSTICS AND THERAPEUTIC TOOLS FOR A PERSONALIZED CARE OF MS PATIENTS. 2017 19 6809 32 [EPIGENETICS IN INFLAMMATORY SYSTEMIC DISEASES]. IN ADDITION TO ANALYSIS OF THE GENETIC CODE, IN RECENT YEARS MORE AND MORE STUDIES HAVE CONCENTRATED ON CHANGES IN THE EPIGENETIC CODE. EPIGENETIC MECHANISMS DETERMINE WHICH GENES IN A CELL ARE TRANSCRIBED AND THUS FORM THE PHENOTYPE OF A CELL. THE EPIGENETIC CODE CAN BE CHANGED BY ENVIRONMENTAL INFLUENCES, WHICH ALLOWS CELLS TO ADAPT TO LONGSTANDING CHANGES IN THE ENVIRONMENT. THEREFORE, IT IS FEASIBLE TO ASSUME THAT EPIGENETIC CHANGES ARE THE MOLECULAR BASIS FOR LONG-TERM EFFECTS OF THE ENVIRONMENT ON DISEASE DEVELOPMENT. IN PARTICULAR IN TUMORS AND CHRONIC INFLAMMATORY DISEASES EPIGENETIC CHANGES WERE FOUND TO CORRELATE WITH DISEASE SEVERITY AND PROGRESSION. KNOWLEDGE ABOUT THESE EPIGENETIC CHANGES MIGHT HELP THAT EPIGENETIC MODIFICATIONS CAN BE USED IN THE FUTURE AS BIOMARKERS, PROGNOSTIC FACTORS AND THERAPEUTIC TARGETS. 2014 20 2945 32 GENETIC AND EPIGENETIC BASIS OF PSORIASIS PATHOGENESIS. PSORIASIS IS A CHRONIC INFLAMMATORY SKIN DISEASE WHOSE PREVALENCE VARIES AMONG DIFFERENT POPULATIONS WORLDWIDE. IT IS A COMPLEX MULTI-FACTORIAL DISEASE AND THE EXACT ETIOLOGY IS LARGELY UNKNOWN. FAMILY BASED STUDIES HAVE INDICATED A GENETIC PREDISPOSITION; HOWEVER THEY CANNOT FULLY EXPLAIN THE DISEASE PATHOGENESIS. IN ADDITION TO GENETIC SUSCEPTIBILITY, ENVIRONMENTAL AS WELL AS GENDER AND AGE RELATED FACTORS WERE ALSO BEEN FOUND TO BE ASSOCIATED. RECENTLY, IMBALANCES IN EPIGENETIC NETWORKS ARE INDICATED TO BE CAUSATIVE ELEMENTS IN PSORIASIS. THE PRESENT KNOWLEDGE OF EPIGENETIC INVOLVEMENT, MAINLY THE DNA METHYLATION, CHROMATIN MODIFICATIONS AND MIRNA DEREGULATION IS SURVEYED HERE. AN INTEGRATED APPROACH CONSIDERING GENETIC AND EPIGENETIC ANOMALIES IN THE LIGHT OF IMMUNOLOGICAL NETWORK MAY EXPLORE THE PATHOGENESIS OF PSORIASIS. 2015