1 3033 171 GENETICS, EPIGENETICS, AND GENDER IMPACT IN AXIAL-SPONDYLOARTHRITIS SUSCEPTIBILITY: AN UPDATE ON GENETIC POLYMORPHISMS AND THEIR SEX RELATED ASSOCIATIONS. SPONDYLOARTHRITIS (SPA) IS A GROUP OF CHRONIC INFLAMMATORY RHEUMATIC DISEASE THAT CAN BE DIVIDED INTO PREDOMINANTLY AXIAL OR PREDOMINANTLY PERIPHERAL INVOLVEMENT, WITH OR WITHOUT ASSOCIATED PSORIASIS, INFLAMMATORY BOWEL DISEASE OR PREVIOUS INFECTION. AXIAL SPA (AXSPA) ENCOMPASSES ANKYLOSING SPONDYLITIS (AS) WITH RADIOLOGICAL SACROILIITIS, AND A TYPE WITHOUT RADIOGRAPHIC SACROILIITIS, CALLED "NON-RADIOGRAPHIC AXIAL SPA" (NR-AXSPA). MALES AND FEMALES SHOW LARGE DIFFERENCES IN THEIR SUSCEPTIBILITY TO SPA, SUCH AS DISTINCTIONS IN CLINICAL PATTERNS, PHENOTYPES AND IN THERAPEUTICAL RESPONSE, PARTICULARLY TO TNF INHIBITORS (TNFI). SEVERAL STUDIES INDICATE THAT AS WOMEN HAVE DOUBLED RISK TO FAILURE TNFI COMPARED WITH MALES. THIS DIVERSITY IN DRUGS' EFFICACY AMONG WOMEN AND MEN MAY BE CAUSED BY DIFFERENCES IN THE BALANCE OF SEX HORMONES AND IN GENE-SPECIFIC EXPRESSION LIKELY TRIGGERED BY X-CHROMOSOME INSTABILITY AND GENE-SPECIFIC EPIGENETIC MODIFICATIONS. EVIDENCE REPORTED THAT POLYMORPHISMS IN MICRORNAS ON X- AND OTHER CHROMOSOMES, SUCH AS MIR-146A, MIR-155, MIR-125A-5P, MIR-151A-3P AND MIR-22-3P, MIR-199A-5P COULD BE INVOLVED IN THE DIFFERENT CLINICAL PRESENTATION OF SPA, AS WELL AS DISEASE ACTIVITY. IN ADDITION, ASSOCIATION WITH NON-RESPONSE TO TNFI TREATMENT AND PRESENCE OF IRAK3 AND CHUCK GENES IN SPA PATIENTS WAS RECENTLY DETECTED. FINALLY, POLYMORPHISMS IN GENES INVOLVED IN IL-23/IL-17 PATHWAY, SUCH AS IN DRUG PHARMACODYNAMICS AND PHARMACOKINETICS MAY HAVE A ROLE IN RESPONSE TO TNFI, IL17I, AND IL23I. A MAJOR UNDERSTANDING OF GENOMIC VARIABILITY COULD HELP IN THE DEVELOPMENT OF NEW THERAPEUTIC TARGETS OR IN TAKING ADVANTAGES OF DIFFERENT MECHANISMS OF ACTION OF BIOLOGICAL DRUGS. MOVING FROM THE MULTIFACTORIAL ETIOLOGY OF DISEASE, THE PRESENT REVIEW AIMS AT EVALUATING GENETIC AND EPIGENETIC FACTORS AND THEIR RELATIONSHIP WITH SEX AND BDMARDS RESPONSE, HELPING TO INVESTIGATE THE DIFFERENT EXPRESSION AMONG MALES AND FEMALES OF GENES ON X- AND OTHER CHROMOSOMES, AS WELL AS MI-RNA, TO HIGHLIGHT RELATIONSHIPS BETWEEN SEX AND OCCURRENCE OF SPECIFIC PHENOTYPES AND SYMPTOMS OF THE DISEASE. MOREOVER, THE ROLE OF THE EPIGENETIC MODIFICATION IN RELATION TO IMMUNE-REGULATORY MECHANISMS WILL BE EVALUATED. 2021 2 2989 39 GENETIC FACTORS INVOLVED IN THE CO?OCCURRENCE OF ENDOMETRIOSIS WITH ANKYLOSING SPONDYLITIS (REVIEW). PREVIOUS RESEARCH HAS REVEALED AN ASSOCIATION BETWEEN ENDOMETRIOSIS AND VARIOUS AUTOIMMUNE DISEASES, WHILE RECENT DATA SUGGEST, FOR THE FIRST TIME, AN ASSOCIATION BETWEEN ENDOMETRIOSIS AND THE RISK OF DEVELOPING ANKYLOSING SPONDYLITIS (AS). AS, THE PROTOTYPE OF SPONDYLOARTHRITIDES DISEASES, IS A SYSTEMIC, CHRONIC, IMMUNE?MEDIATED INFLAMMATORY ARTHRITIS, WHICH PRIMARILY AFFECTS THE SPINE AND SACROILIAC JOINTS, AS WELL AS THE AXIAL SKELETON WITH OR WITHOUT EXTRASPINAL MANIFESTATIONS. AS IS OF POLYGENIC INHERITANCE AND NUMEROUS IMMUNOLOGICALLY RELEVANT GENES CONTRIBUTE TO ITS DEVELOPMENT. ENDOMETRIOSIS IS AN ENIGMATIC, RELATIVELY COMMON, BENIGN, ESTROGEN?DEPENDENT, HETEROGENEOUS GYNECOLOGICAL DISEASE, INFLUENCED BY MULTIPLE GENETIC, EPIGENETIC AND ENVIRONMENTAL FACTORS. IT IS CHARACTERIZED BY THE GROWTH OF ENDOMETRIAL TISSUE OCCURRING IN SITES OTHER THAN THE UTERINE CAVITY, MOST COMMONLY IN THE PELVIC CAVITY, INCLUDING THE OVARIES AND THE UTEROSACRAL LIGAMENTS, AFFECTING UP TO 10% OF THE FEMALE POPULATION OF CHILDBEARING AGE, CAUSING PAIN AND INFERTILITY. THE PRESENT REVIEW DISCUSSES WHETHER A PARTIALLY SHARED GENETIC BACKGROUND MAY EXPLAIN THE CO?OCCURRENCE OF THESE DISORDERS, AS WELL AS POTENTIAL SIMILARITIES REGARDING THE UNDERLYING PATHOGENETIC MECHANISMS AND SPECIFIC MOLECULAR AND CELLULAR PATHWAYS. 2023 3 2027 42 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 4 4319 35 MICRORNAS IN AXIAL SPONDYLARTHRITIS: AN OVERVIEW OF THE RECENT PROGRESSES IN THE FIELD WITH A FOCUS ON ANKYLOSING SPONDYLITIS AND PSORIATIC ARTHRITIS. PURPOSE OF REVIEW: TO HIGHLIGHT THE RECENT DISCOVERIES AND LINES OF EVIDENCE ON THE ROLE OF MICRORNAS IN ANKYLOSING SPONDYLITIS (AS) AND PSORIATIC ARTHRITIS (PSA), FOCUSING ON THEIR EXPRESSION PROFILING AND MECHANISMS OF ACTION. RECENT FINDINGS: AS AND PSA ARE CHRONIC INFLAMMATORY MUSCULOSKELETAL DISEASES WITH AXIAL MANIFESTATIONS AND REPRESENT AN EXCELLENT MODEL FOR STUDYING MICRORNAS CONTRIBUTION TO THE DISEASE PATHOGENESIS, PARTICULARLY THROUGH IMMUNOMODULATION, INFLAMMATION, AND BONE REMODELLING, OR THEIR VALUE AS CANDIDATE DIAGNOSTIC AND PROGNOSTIC BIOMARKERS. MICRORNAS ARE SINGLE-STRANDED NUCLEOTIDES ABLE TO REGULATE GENE EXPRESSION. THEY ARE A KEY COMPONENT OF THE EPIGENETIC MACHINERY, INVOLVED IN PHYSIOLOGICAL AND PATHOLOGICAL PROCESSES. THE CONTRIBUTION OF MICRORNAS IN AS AND PSA (SUCH AS MIR-29A IN REGULATING BONE METABOLISM) IS HIGHLIGHTED BY SEVERAL WORKS IN THE FIELD BUT THEIR UTILITY AS POSSIBLE MARKERS MUST BE STILL CONFIRMED, PARTICULARLY IN LARGER PATIENTS' COHORTS. 2021 5 4318 31 MICRORNAS IN ANKYLOSING SPONDYLITIS: FUNCTION, POTENTIAL AND CHALLENGES. EPIGENETIC MECHANISMS SUCH AS DNA METHYLATION, HISTONE MODIFICATIONS AND NON-CODING RNA, ARE CONSIDERED THE ESSENTIAL CONNECTION BETWEEN A DISORDER'S ONSET AND THE ENVIRONMENT, ON A PERMISSIVE GENETIC BACKGROUND. AMONG AUTOIMMUNE AND INFLAMMATORY-MEDIATED DISORDERS, ANKYLOSING SPONDYLITIS (AS), A CHRONIC ARTHRITIS OF THE SPINE, IS A VERY GOOD EXAMPLE FOR THE WEIGHT OF EPIGENETICS' CONTRIBUTION. MICRORNAS (MIRNAS) ARE SINGLE-STRANDED NUCLEOTIDES WHICH REGULATE GENE EXPRESSION AND ARE INVOLVED IN PATHOLOGICAL AND PHYSIOLOGICAL PROCESSES. IN THIS MANUSCRIPT WE PROVIDE A CLARIFICATION ON THE ROLE OF MICRORNAS IN AS, WITH A FOCUS ON THE MECHANISMS OF PATHOGENESIS. IN SPECIFIC, WE HAVE EXAMINED THE CONTRIBUTION OF MIRNAS IN THE PROCESSES OF INFLAMMATION, NEW BONE FORMATION AND T-CELL FUNCTION, AND THE PATHWAYS (I.E. WNT, BMP, TGFBETA SIGNALLING ETC.) THEY REGULATE. THE UTILITY OF MIRNAS IN BETTER UNDERSTANDING AS PATHOGENESIS IS UNDISPUTED AND THEIR UTILITY AS THERAPEUTIC OPPORTUNITY IS STRONGLY INCREASING. 2020 6 2569 36 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 7 1935 42 ENVIRONMENTAL RISK FACTORS AND EPIGENETIC ALTERNATIONS IN PSORIASIS. INTRODUCTION AND OBJECTIVE: PSORIASIS ISA QUITE COMMON, CHRONIC AND IMMUNE-MEDIATED SKIN DISORDER. THE PREVALENCE OF PSORIASIS DIFFERS IN VARIOUS COUNTRIES, BUT IT IS SAID TO AFFECT 2% OF THE WORLD'S POPULATION IN GENERAL. PSORIASIS HAS MANY DIFFERENT CLINICAL FEATURES BUT ALL LESIONS HAVE THE SAME CHARACTERISTIC: ERYTHEMA, THICKENING AND SCALE, ALTHOUGH OTHER CLINICAL FEATURES ARE ALSO CONNECTED, SUCH AS PSORIATIC ARTHRITIS, OBESITY AND METABOLIC SYNDROME. ALL OF THESE MAY LEAD TO CONDITIONS IMPAIRING THE QUALITY OF LIFE. THIS REVIEW IS AN ATTEMPT TO SUMMARIZE RECENT DATA REGARDING ENVIRONMENTAL FACTORS, TOGETHER WITH EPIGENETIC MARKERS AND PROCESSES PLAYING AN IMPORTANT ROLE IN PSORIASIS. STATE OF KNOWLEDGE: MANY DIFFERENT ENVIRONMENTAL FACTORS PLAY A ROLE IN GENETICALLY PREDISPOSED PATIENTS. THIS IS CAUSES EPIGENETIC ALTERNATIONS WHICH MAY BE A LINKING PART IN THE WHOLE PROCESS. MANY STUDIES HAVE INDICATED A CONNECTION BETWEEN PSORIASIS AND VARIOUS GENES AND ANTIGENS. THE PRESENCE OF HLA-CW6 IS COMMON AS WELL A STRONG LINK BETWEEN ITS PRESENCE AND THE ONSET OF PSORIASIS BEING OBSERVED. THE MAIN ALTERNATIONS ARE DNA METHYLATION, HISTONE'S MODIFICATIONS AND THE ROLE OF MICRORNA. EXCESSIVE REACTION IS USUALLY NOT PRESENT WITHOUT A TRIGGERING FACTOR. ENVIRONMENTAL FACTORS ARE MOSTLY RATED, SUCH AS DRUGS, LIFE STYLE AND HABITS (SMOKING, ALCOHOL), DIET, PHYSICAL TRAUMA (SKIN INJURY PROVOKING KOEBNER PHENOMENON), STRESS, MICROORGANISM AND INFECTIONS. CONCLUSIONS: THE CORRELATION BETWEEN PATHOGENESIS OF PSORIASIS AND ENVIRONMENTAL RISK FACTORS, TOGETHER WITH EPIGENETIC ALTERNATIONS STILL REQUIRE MORE INVESTIGATION. EDUCATION ABOUT DIET HABITS, NUTRITION, WEIGHT LOSS AND HEALTHY LIFESTYLE SEEMS TO BE IMPORTANT DURING THE TREATMENT OF PSORIASIS. 2020 8 4676 47 NEW INSIGHTS TOWARD THE PATHOGENESIS OF ANKYLOSING SPONDYLITIS; GENETIC VARIATIONS AND EPIGENETIC MODIFICATIONS. ANKYLOSING SPONDYLITIS (AS) IS A CHRONIC INFLAMMATORY AUTOIMMUNE DISEASE, CHARACTERIZED BY TYPICALLY AN AXIAL ARTHRITIS. AS IS THE PROTOTYPE OF A GROUP OF DISORDERS CALLED SPONDYLOARTHROPATHIES, WHICH IS BELIEVED TO HAVE COMMON CLINICAL MANIFESTATIONS AND GENETIC PREDISPOSITION. TO DATE, THE EXACT ETIOLOGY OF AS REMAINS UNCLEAR. OVER THE PAST FEW YEARS, HOWEVER, THE ROLE OF GENETIC SUSCEPTIBILITY AND EPIGENETIC MODIFICATIONS CAUSED THROUGH ENVIRONMENTAL FACTORS HAVE BEEN EXTENSIVELY SURVEYED WITH RESPECT TO THE PATHOGENESIS OF AS, RESULTED IN IMPORTANT ADVANCES. THIS REVIEW ARTICLE FOCUSES ON THE RECENT ADVANCES IN THE FIELD OF AS RESEARCH, INCLUDING HLA AND NON-HLA SUSCEPTIBILITY GENES IDENTIFIED IN GENOME-WIDE ASSOCIATION STUDIES (GWAS), AND ABERRANT EPIGENETIC MODIFICATIONS OF GENE LOCI ASSOCIATED WITH AS. HLA GENES MOST SIGNIFICANTLY LINKED WITH AS SUSCEPTIBILITY INCLUDE HLA-B27 AND ITS SUBTYPES. NUMEROUS NON-HLA GENES SUCH AS THOSE IN UBIQUITINATION, AMINOPEPTIDASES AND MHC CLASS I PRESENTATION MOLECULES LIKE ERAP-1 WERE ALSO REPORTED. MOREOVER, EPIGENETIC MODIFICATIONS OCCURRED IN AS HAS BEEN SUMMARIZED. TAKEN TOGETHER, THE FINDINGS PRESENTED IN THIS REVIEW ATTEMPT TO EXPLAIN THE CIRCUMSTANCE BY WHICH BOTH GENETIC VARIATIONS AND EPIGENETIC MODIFICATIONS ARE INVOLVED IN TRIGGERING AND DEVELOPMENT OF AS. NONETHELESS, SEVERAL UNANSWERED DARK SIDES CONTINUE TO CLOG OUR EXHAUSTIVE UNDERSTANDING OF AS. FUTURE RESEARCHES IN THE FIELD OF EPIGENETICS SHOULD BE CARRIED OUT TO EXTEND OUR VISION OF AS ETIOPATHOGENESIS. 2017 9 4962 50 PATHOGENESIS OF PSORIATIC ARTHRITIS. PSORIATIC ARTHRITIS (PSA) IS A CHRONIC INFLAMMATORY ARTHROPATHY INVOLVING SYNOVIAL AND ENTHESEAL STRUCTURES, ASSOCIATED WITH PSORIASIS OR SIMILAR CONDITIONS. THE ETIOPATHOGENETIC MECHANISMS UNDERLYING PSA REMAIN UNCLARIFIED. THE MOST ACCREDITED HYPOTHESIS INVOLVES A COMPLEX INTERACTION AMONG GENETIC, ENVIRONMENTAL, AND IMMUNOLOGICAL FACTORS. ENVIRONMENTAL AGENTS, PARTICULARLY TRAUMA, MECHANICAL STRESS, AND SMOKE HAVE BEEN CITED AS POSSIBLE FACTORS IN TRIGGERING THE DISEASE IN GENETICALLY PREDISPOSED SUBJECTS. LIKE OTHER FORMS OF SPONDYLOARTHROPATHIES, PSA SHOWS SEVERAL GENETIC ASSOCIATIONS WITH THE MAJOR HISTOCOMPATIBILITY COMPLEX (MHC) CLASS I ALLELES LOCATED ON CHROMOSOME 6P21.3, PARTICULARLY THE HUMAN LEUKOCYTE ANTIGEN (HLA)-B27 IN AXIAL PHENOTYPES. RECENT STUDIES HAVE DEMONSTRATED THAT THE MOST COMMON EPIGENETIC MECHANISMS THAT REGULATE GENE EXPRESSION IN PSA ARE REPRESENTED BY DNA METHYLATION, PARENT OF ORIGIN EFFECT OR GENOMIC IMPRINTING, EXPRESSION OR ACTIVITY OF EPIGENETIC MODIFYING ENZYMES, AND RNA INTERFERENCE (RNAI) BY MICRORNAS (MIRNAS). THE MECHANISMS UNDERLYING PSA PATHOGENESIS ACTIVATE THE INNATE AND ADAPTIVE IMMUNE SYSTEM AND OVEREXPRESSION OF TNF ASSOCIATED WITH AMPLIFICATION OF THE IL-23/IL-17 AXIS. IN RECENT YEARS, MORE PSA SUSCEPTIBILITY GENES AND EPIGENETIC MECHANISMS HAVE BEEN IDENTIFIED. ADVANCES IN THE KNOWLEDGE OF INNATE AND ADAPTIVE IMMUNE MECHANISMS UNDERLYING PSA HAVE CONTRIBUTED TO A BETTER UNDERSTANDING OF THE HETEROGENEOUS CLINICAL EXPRESSION OF THE DISEASE AND, THUS, TO THERAPY STRATEGIES. THE COMPLEXITY OF THE PATHOGENETIC ASPECTS INVOLVING MULTIPLE CYTOKINES, CELL LINES, AND MOLECULES NEEDS TO BE FURTHER INVESTIGATED TO ADVANCE PERSONALIZED THERAPEUTIC STRATEGIES AND TO IMPROVE OUTCOMES OF PATIENTS AFFECTED BY PSA. 2019 10 4961 41 PATHOGENESIS OF PSORIASIS IN THE "OMIC" ERA. PART II. GENETIC, GENOMIC AND EPIGENETIC CHANGES IN PSORIASIS. PSORIASIS IS A MULTIFACTORIAL DISEASE IN WHICH GENETIC, ENVIRONMENTAL AND EPIGENETIC FACTORS REGULATING GENE EXPRESSION PLAY A KEY ROLE. IN THE "GENOMIC ERA", GENOME-WIDE ASSOCIATION STUDIES TOGETHER WITH TARGET GENOTYPING PLATFORMS PERFORMED IN DIFFERENT ETHNIC POPULATIONS HAVE FOUND MORE THAN 50 GENETIC SUSCEPTIBLE MARKERS ASSOCIATED WITH THE RISK OF PSORIASIS WHICH HAVE BEEN IDENTIFIED SO FAR. UP TILL NOW, THE STRONGEST ASSOCIATION WITH THE RISK OF THE DISEASE HAS BEEN PROVED FOR HLA-C*06 GENE. THE MAJORITY OF OTHER PSORIASIS RISK SNPS ARE SITUATED NEAR THE GENES ENCODING MOLECULES INVOLVED IN ADAPTIVE AND INNATE IMMUNITY, AND SKIN BARRIER FUNCTION. MANY CONTEMPORARY STUDIES INDICATE THAT THE EPIGENETIC CHANGES: HISTONE MODIFICATION, PROMOTER METHYLATIONS, LONG NON-CODING AND MICRO-RNA HYPEREXPRESSION ARE CONSIDERED AS FACTORS CONTRIBUTING TO PSORIASIS PATHOGENESIS AS THEY REGULATE ABNORMAL KERATINOCYTE DIFFERENTIATION AND PROLIFERATION, ABERRANT KERATINOCYTES - INFLAMMATORY CELLS COMMUNICATION, NEOANGIOGENESIS AND CHRONIC INFLAMMATION. THE CIRCULATING MIRNAS DETECTED IN THE BLOOD MAY BECOME SPECIFIC MARKERS IN THE DIAGNOSIS, PROGNOSIS AND RESPONSE TO THE TREATMENT OF THE DISEASE. THE INHIBITION OF EXPRESSION IN SELECTED MIRNAS MAY BE A NEW PROMISING THERAPY OPTION FOR PATIENTS WITH PSORIASIS. 2020 11 3020 42 GENETICS AND EPIGENETICS OF OSTEOARTHRITIS. OSTEOARTHRITIS (OA) IS A COMMON AGE-RELATED DISEASE THAT AFFECTS THE TISSUES OF THE SYNOVIAL JOINT, LEADING TO LOSS OF FUNCTION AND PAIN. IT IMPACTS ON BOTH PATIENT MORBIDITY AND MORTALITY. IT IS A COMPLEX, POLYGENIC DISEASE THAT LACKS ANY LARGE-EFFECT SUSCEPTIBILITY LOCI. INSTEAD, OA SUSCEPTIBILITY ALLELES INDIVIDUALLY CONTRIBUTE ONLY MODESTLY TO THE OVERALL DISEASE RISK, MAKING THEIR IDENTIFICATION CHALLENGING. DESPITE THIS, BREAKTHROUGHS HAVE OCCURRED WITH COMPELLING ASSOCIATIONS SO FAR REPORTED TO POLYMORPHISMS WITHIN THE GENES GDF5 AND MCF2L AND TO THE GENOMIC REGION 7Q22. THE LATTER TWO HAVE EMERGED FROM GENOME-WIDE ASSOCIATION SCANS, WHICH ARE LIKELY TO YIELD MORE HITS IN THE NEAR FUTURE. AS FOR MANY COMPLEX DISEASES, IT IS NOW APPARENT THAT EPIGENETIC EFFECTS ARE ALSO IMPORTANT MEDIATORS OF DISEASE BIOLOGY, WITH DNA METHYLATION, HISTONE MODIFICATIONS AND NON-CODING RNAS ALL HAVING A ROLE. AT PRESENT, MUCH OF THE EPIGENETIC FOCUS HAS BEEN ON CARTILAGE, THE TISSUE AT THE CENTER OF THE OA DISEASE PROCESS. IF WE ARE TO GET CLOSE TO A QUALITATIVE AND QUANTITATIVE UNDERSTANDING OF THE IMPACT OF EPIGENETICS ON OA, THEN IN FUTURE THE OTHER TISSUES OF THE JOINT WILL ALSO NEED TO BE INVESTIGATED. ONE OF THE MORE EXCITING INSIGHTS TO HAVE EMERGED RECENTLY IS THE FACT THAT EPIGENETIC EFFECTS CAN IMPACT ON OA GENETIC EFFECTS AND THIS MAY BE A PARTICULARLY FRUITFUL AVENUE FOR INTEGRATING BOTH AS WE MOVE TOWARD A CLEARER UNDERSTANDING OF THE PATHOPHYSIOLOGY OF THIS INTRIGUING DISEASE. 2012 12 2945 33 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 13 2595 44 EPIGENETICS OF SPONDYLOARTHRITIS. SPONDYLOARTHRITIS (SPA) IS A CHRONIC INFLAMMATORY DISORDER RESULTING FROM A COMBINATION OF GENETIC PREDISPOSITION AND ENVIRONMENTAL FACTORS. DESPITE RECENT ADVANCES, A SUBSTANTIAL FRACTION OF ITS GENETIC BASIS REMAINS POORLY UNDERSTOOD. SEVERAL MECHANISMS HAVE BEEN PROPOSED TO ACCOUNT FOR THIS UNEXPLAINED HERITABILITY, INCLUDING EPIGENETICS WHICH CAN PLAY A ROLE AT THE INTERFACE BETWEEN GENETIC AND ENVIRONMENTAL SUSCEPTIBILITY FACTORS. EPIGENETICS REFERS TO CHANGES IN GENE EXPRESSION THAT ARE NOT ENCODED IN THE DNA SEQUENCE ITSELF. SUCH MECHANISMS MAY INCLUDE DNA METHYLATION, HISTONE MODIFICATIONS AND NON-CODING RNAS. DISRUPTION OF ONE OF THESE SYSTEMS CAN LEAD TO INAPPROPRIATE GENE EXPRESSION, WHICH IN TURN MIGHT FAVOUR THE DEVELOPMENT OF DISEASE. THANKS TO RECENT TECHNOLOGICAL PROGRESS, THERE HAS BEEN A GROWING INTEREST IN THE FIELD OF EPIGENETICS IN COMPLEX DISEASES, INCLUDING SPA. HOWEVER, EPIGENETIC STUDIES FACE SOME METHODOLOGICAL LIMITATIONS THAT HAMPER INTERPRETATION OF THEIR RESULTS: SMALL SAMPLE SIZE, ABSENCE OF BIOLOGICAL REPLICATION, LACK OF ADEQUATE CONTROLS FOR POTENTIAL CONFOUNDERS, STUDIES NOT PERFORMED IN THE MOST RELEVANT CELL/TISSUES. IN THE FUTURE, INTEGRATION OF EPIGENETICS WITH OTHER "OMICS" DATA WILL PROBABLY BE NECESSARY TO IMPROVE OUR UNDERSTANDING OF SPA PATHOGENESIS. THESE ISSUES NEED TO BE ADDRESSED BEFORE CONSIDERING THE USE OF EPIGENETIC MARKS IN CLINICAL ROUTINE, AS BIOMARKERS OR AS DRUG TARGETS. 2020 14 6624 39 UNDERSTANDING PSORIASIS: ROLE OF MIRNAS. PSORIASIS IS A CHRONIC, IMMUNE-MEDIATED INFLAMMATORY SKIN DISEASE, WITH A MULTIFACTORIAL ETIOLOGY AND IMPORTANT IMMUNOLOGIC, GENETIC AND ENVIRONMENTAL COMPONENTS. PSORIASIS VULGARIS REPRESENTS ITS MOST COMMON FORM, WITH A VARIABLE PREVALENCE ACROSS THE GLOBE. ALTHOUGH ITS PATHOGENESIS REMAINS TO BE FULLY ELUCIDATED, A LACK OF BALANCE IN THE EPIGENETIC NETWORK HAS BEEN SHOWN TO TRIGGER CERTAIN ELEMENTS OF THIS DISEASE, POSSIBLY ALTERING ITS OUTCOME. MICRORNAS ARE SMALL NON-CODING RNA MOLECULES INVOLVED IN RNA-SILENCING AND THE POST-TRANSCRIPTIONAL REGULATION OF GENE EXPRESSION, WHICH ALSO APPEAR TO MEDIATE THE IMMUNE DYSFUNCTION IN PSORIASIS. ALTHOUGH MICRORNA RESEARCH IS A NEW FIELD IN DERMATOLOGY AND PSORIASIS, THERE IS RAPIDLY ACCUMULATING EVIDENCE FOR ITS MAJOR CONTRIBUTION IN THE PATHOGENESIS OF CHRONIC INFLAMMATORY CONDITIONS, INCLUDING PSORIASIS AND OTHER DERMATOLOGICAL DISORDERS. FURTHERMORE, CIRCULATING MIRNAS IDENTIFIED IN PATIENTS' BLOOD SAMPLES HAVE BEEN IDENTIFIED AS PROMISING BIOMARKERS OF DIAGNOSIS, PROGNOSIS OR TREATMENT RESPONSE. EXTENDED INVESTIGATIONS IN THIS FIELD ARE REQUIRED, AS UNTIL NOW, THE EXACT INVOLVEMENT OF MIRNAS IN PSORIASIS HAVE REMAINED TO BE ENTIRELY ELUCIDATED. THIS SHORT REVIEW HIGHLIGHTS A NUMBER OF THE ROLES OF MIRNAS FOUND IN DIFFERENT STAGES OF PSORIASIS. 2018 15 2553 38 EPIGENETICS IN PSORIASIS: PERSPECTIVE OF DNA METHYLATION. PSORIASIS IS A CHRONIC INFLAMMATORY SKIN DISEASE CHARACTERIZED BY EXCESSIVE PROLIFERATION OF KERATINOCYTES (KCS). ONSET OF PSORIASIS IS RELATED TO GENETIC, IMMUNE AND ENVIRONMENTAL FACTORS. THE ENVIRONMENT CAN INTERACT WITH THE GENOME THROUGH EPIGENETIC MODIFICATIONS, INCLUDING DNA METHYLATION, AND THIS MODIFICATION IS INVOLVED IN THE PATHOGENESIS OF PSORIASIS. IN ADDITION TO A SKIN DISEASE, PSORIASIS IS ALSO CONSIDERED A SYSTEMIC DISEASE. WE REVIEWED THE CURRENT LITERATURE OF PSORIATIC DNA METHYLATION FOR STUDIES FROM SEVERAL ASPECTS ON THE DNA METHYLATION DISTRIBUTION PATTERNS IN DIFFERENT TISSUES/CELLS, SINGLE-NUCLEOTIDE POLYMORPHISMS, AND CANDIDATE DISEASE GENES AND IDENTIFIED TARGET GENES REGULATED BY DNA METHYLATION THAT HAVE BEEN DIRECTLY/INDIRECTLY VALIDATED. THIS REVIEW CONTRIBUTES TO A COMPREHENSIVE UNDERSTANDING OF THE IMPORTANT A ROLE THAT DNA METHYLATION PLAYS IN PSORIASIS FROM A HOLISTIC PERSPECTIVE AND WILL PROMOTE THE IMPLEMENTATION OF DNA METHYLATION IN DIAGNOSTIC AND THERAPEUTIC STRATEGIES FOR PSORIATIC PATIENTS. 2021 16 5643 47 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 17 1524 33 DNA METHYLATION CHANGES IN CYSTIC FIBROSIS: CAUSE OR CONSEQUENCE? TWIN AND SIBLING STUDIES HAVE SHOWN THAT LUNG DISEASE SEVERITY IS VARIABLE AMONG CYSTIC FIBROSIS (CF) PATIENTS AND AFFECTED TO THE SAME EXTENT BY GENETIC AND NONHERITABLE FACTORS. GENETIC FACTORS HAVE BEEN THOROUGHLY ASSESSED, WHEREAS THE MOLECULAR MECHANISMS WHEREBY NONHERITABLE FACTORS CONTRIBUTE TO THE PHENOTYPIC VARIABILITY OF CF PATIENTS ARE STILL UNKNOWN. EPIGENETIC MODIFICATIONS MAY REPRESENT THE MISSING LINK BETWEEN NONHERITABLE FACTORS AND PHENOTYPIC VARIATION IN CF. HEREIN, WE REVIEW RECENT STUDIES SHOWING THAT DNA METHYLATION IS ALTERED IN CF AND WE ADDRESS THREE POSSIBLE FACTORS RESPONSIBLE FOR THESE VARIATIONS: (I) OVERPRODUCTION OF REACTIVE OXYGEN SPECIES, (II) DEPLETION OF DNA METHYLATION COFACTORS AND (III) SUSCEPTIBILITY TO ACUTE AND CHRONIC BACTERIAL INFECTIONS. ALSO, WE HYPOTHESIZE THAT THE UNIQUE DNA METHYLATION PROFILE OF EACH PATIENT CAN MODULATE THE PHENOTYPE AND DISCUSS THE INTEREST OF IMPLEMENTING INTEGRATED GENOMIC, EPIGENOMIC AND TRANSCRIPTOMIC STUDIES TO FURTHER UNDERSTAND THE CLINICAL DIVERSITY OF CF PATIENTS (GRAPHICAL ABSTRACT). 2020 18 2591 44 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 19 2279 44 EPIGENETIC REGULATION IN ALLERGIC DISEASES AND RELATED STUDIES. ASTHMA, A CHRONIC INFLAMMATORY DISORDER OF THE AIRWAY, HAS FEATURES OF BOTH HERITABILITY AS WELL AS ENVIRONMENTAL INFLUENCES WHICH CAN BE INTRODUCED IN UTERO EXPOSURES AND MODIFIED THROUGH AGING, AND THE FEATURES MAY ATTRIBUTE TO EPIGENETIC REGULATION. EPIGENETIC REGULATION EXPLAINS THE ASSOCIATION BETWEEN EARLY PRENATAL MATERNAL SMOKING AND LATER ASTHMA-RELATED OUTCOMES. EPIGENETIC MARKS (DNA METHYLATION, MODIFICATIONS OF HISTONE TAILS OR NONCODING RNAS) WORK WITH OTHER COMPONENTS OF THE CELLULAR REGULATORY MACHINERY TO CONTROL THE LEVELS OF EXPRESSED GENES, AND SEVERAL ALLERGY- AND ASTHMA-RELATED GENES HAVE BEEN FOUND TO BE SUSCEPTIBLE TO EPIGENETIC REGULATION, INCLUDING GENES IMPORTANT TO T-EFFECTOR PATHWAYS (IFN-GAMMA, INTERLEUKIN [IL] 4, IL-13, IL-17) AND T-REGULATORY PATHWAYS (FOXP3). THEREFORE, THE MECHANISM BY WHICH EPIGENETIC REGULATION CONTRIBUTES TO ALLERGIC DISEASES IS A CRITICAL ISSUE. IN THE PAST MOST PUBLISHED EXPERIMENTAL WORK, WITH FEW EXCEPTIONS, HAS ONLY COMPRISED SMALL OBSERVATIONAL STUDIES AND MODELS IN CELL SYSTEMS AND ANIMALS. HOWEVER, VERY RECENTLY EXCITING AND ELEGANT EXPERIMENTAL STUDIES AND NOVEL TRANSLATIONAL RESEARCH WORKS WERE PUBLISHED WITH NEW AND ADVANCED TECHNOLOGIES INVESTIGATING EPIGENETIC MARK ON A GENOMIC SCALE AND COMPREHENSIVE APPROACHES TO DATA ANALYSIS. INTERESTINGLY, A POTENTIAL LINK BETWEEN EXPOSURE TO ENVIRONMENTAL POLLUTANTS AND THE OCCURRENCE OF ALLERGIC DISEASES IS REVEALED RECENTLY, PARTICULAR IN DEVELOPED AND INDUSTRIALIZED COUNTRIES, AND ENDOCRINE DISRUPTING CHEMICALS (EDCS) AS ENVIRONMENTAL HORMONE MAY PLAY A KEY ROLE. THIS REVIEW ADDRESSES THE IMPORTANT QUESTION OF HOW EDCS (NONYLPHENOL, 4 OCTYLPHENOL, AND PHTHALATES) INFLUENCES ON ASTHMA-RELATED GENE EXPRESSION VIA EPIGENETIC REGULATION IN IMMUNE CELLS, AND HOW ANTI-ASTHMATIC AGENTS PROHIBIT EXPRESSION OF INFLAMMATORY GENES VIA EPIGENETIC MODIFICATION. THE DISCOVERY AND VALIDATION OF EPIGENETIC BIOMARKERS LINKING EXPOSURE TO ALLERGIC DISEASES MIGHT LEAD TO BETTER EPIGENOTYPING OF RISK, PROGNOSIS, TREATMENT PREDICTION, AND DEVELOPMENT OF NOVEL THERAPIES. 2014 20 2984 45 GENETIC DETERMINANTS OF POOR RESPONSE TO TREATMENT IN SEVERE ASTHMA. SEVERE ASTHMA IS A MULTIFACTORIAL DISORDER WITH MARKED PHENOTYPIC HETEROGENEITY AND COMPLEX INTERACTIONS BETWEEN GENETICS AND ENVIRONMENTAL RISK FACTORS, WHICH COULD, AT LEAST IN PART, EXPLAIN WHY DURING STANDARD PHARMACOLOGIC TREATMENT, MANY PATIENTS REMAIN POORLY CONTROLLED AND AT AN INCREASED RISK OF AIRWAY REMODELING AND DISEASE PROGRESSION. THE CONCEPT OF "PRECISION MEDICINE" TO BETTER SUIT INDIVIDUAL UNIQUE NEEDS IS AN EMERGING TREND IN THE MANAGEMENT OF CHRONIC RESPIRATORY DISEASES. OVER THE PAST FEW YEARS, GENOME-WIDE ASSOCIATION STUDIES (GWAS) HAVE REVEALED NOVEL PHARMACOGENETIC VARIANTS RELATED TO RESPONSES TO INHALED CORTICOSTEROIDS AND THE CLINICAL EFFICACY OF BRONCHODILATORS. OPTIMAL CLINICAL RESPONSE TO TREATMENT MAY VARY BETWEEN RACIAL/ETHNIC GROUPS OR INDIVIDUALS DUE TO GENETIC DIFFERENCES. IT IS ALSO PLAUSIBLE TO ASSUME THAT EPIGENETIC FACTORS PLAY A KEY ROLE IN THE MODULATION OF GENE EXPRESSION PATTERNS AND INFLAMMATORY CYTOKINES. REMARKABLY, SPECIFIC GENETIC VARIANTS RELATED TO TREATMENT EFFECTIVENESS MAY INDICATE PROMISING PATHWAYS FOR NOVEL THERAPIES IN SEVERE ASTHMA. IN THIS REVIEW, WE PROVIDE A CONCISE UPDATE OF GENETIC DETERMINANTS OF POOR RESPONSE TO TREATMENT IN SEVERE ASTHMA AND FUTURE DIRECTIONS IN THE FIELD. 2021