1 2973 155 GENETIC AND EPIGENETIC STUDIES OF ATOPIC DERMATITIS. BACKGROUND: ATOPIC DERMATITIS (AD) IS A CHRONIC INFLAMMATORY DISEASE CAUSED BY THE COMPLEX INTERACTION OF GENETIC, IMMUNE AND ENVIRONMENTAL FACTORS. THERE HAVE MANY RECENT DISCOVERIES INVOLVING THE GENETIC AND EPIGENETIC STUDIES OF AD. METHODS: A RETROSPECTIVE PUBMED SEARCH WAS CARRIED OUT FROM JUNE 2009 TO JUNE 2016 USING THE TERMS "ATOPIC DERMATITIS", "ASSOCIATION", "ECZEMA", "GENE", "POLYMORPHISM", "MUTATION", "VARIANT", "GENOME WIDE ASSOCIATION STUDY", "MICROARRAY" "GENE PROFILING", "RNA SEQUENCING", "EPIGENETICS" AND "MICRORNA". A TOTAL OF 132 PUBLICATIONS IN ENGLISH WERE IDENTIFIED. RESULTS: TO ELUCIDATE THE GENETIC FACTORS FOR AD PATHOGENESIS, CANDIDATE GENE ASSOCIATION STUDIES, GENOME-WIDE ASSOCIATION STUDIES (GWAS) AND TRANSCRIPTOMIC PROFILING ASSAYS HAVE BEEN PERFORMED IN THIS PERIOD. EPIGENETIC MECHANISMS FOR AD DEVELOPMENT, INCLUDING GENOMIC DNA MODIFICATION AND MICRORNA POSTTRANSCRIPTIONAL REGULATION, HAVE BEEN EXPLORED. TO DATE, CANDIDATE GENE ASSOCIATION STUDIES INDICATE THAT FILAGGRIN (FLG) NULL GENE MUTATIONS ARE THE MOST SIGNIFICANT KNOWN RISK FACTOR FOR AD, AND GENES IN THE TYPE 2 T HELPER LYMPHOCYTE (TH2) SIGNALING PATHWAYS ARE THE SECOND REPLICATED GENETIC RISK FACTOR FOR AD. GWAS STUDIES IDENTIFIED 34 RISK LOCI FOR AD, THESE LOCI ALSO SUGGEST THAT GENES IN IMMUNE RESPONSES AND EPIDERMAL SKIN BARRIER FUNCTIONS ARE ASSOCIATED WITH AD. ADDITIONALLY, GENE PROFILING ASSAYS DEMONSTRATED AD IS ASSOCIATED WITH DECREASED GENE EXPRESSION OF EPIDERMAL DIFFERENTIATION COMPLEX GENES AND ELEVATED TH2 AND TH17 GENES. HYPOMETHYLATION OF TSLP AND FCER1G IN AD WERE REPORTED; AND MIR-155, WHICH TARGET THE IMMUNE SUPPRESSOR CTLA-4, WAS FOUND TO BE SIGNIFICANTLY OVER-EXPRESSED IN INFILTRATING T CELLS IN AD SKIN LESIONS. CONCLUSIONS: THE RESULTS SUGGEST THAT TWO MAJOR BIOLOGIC PATHWAYS ARE RESPONSIBLE FOR AD ETIOLOGY: SKIN EPITHELIAL FUNCTION AND INNATE/ADAPTIVE IMMUNE RESPONSES. THE DYSFUNCTIONAL EPIDERMAL BARRIER AND IMMUNE RESPONSES RECIPROCALLY AFFECT EACH OTHER, AND THEREBY DRIVE DEVELOPMENT OF AD. 2016 2 6643 58 UNRAVELLING THE COMPLEX GENETIC BACKGROUND OF ATOPIC DERMATITIS: FROM GENETIC ASSOCIATION RESULTS TOWARDS NOVEL THERAPEUTIC STRATEGIES. ATOPIC DERMATITIS (AD) IS A CHRONIC INFLAMMATORY SKIN DISEASE ARISING FROM COMPLEX INTERACTION BETWEEN GENETIC AND ENVIRONMENTAL FACTORS. AS THE STARTING POINT OF THE SO-CALLED "ATOPIC MARCH", E.G. THE PROGRESSION TOWARDS ALLERGIC ASTHMA IN SOME BUT NOT ALL AFFECTED CHILDREN, AD HAS COME INTO FOCUS FOR POTENTIAL DISEASE-MODIFYING STRATEGIES. TO ELUCIDATE THE GENETIC FACTORS INFLUENCING AD DEVELOPMENT, LINKAGE, ASSOCIATION AS WELL AS GENOME-WIDE ASSOCIATION STUDIES HAVE BEEN PERFORMED OVER THE LAST TWO DECADES. THE RESULTS SUGGEST THAT BESIDES VARIATION IN IMMUNE-MEDIATED PATHWAYS, AN INTACT SKIN BARRIER FUNCTION PLAYS A KEY ROLE IN AD DEVELOPMENT. MUTATIONS IN THE GENE ENCODING FILAGGRIN, A MAJOR STRUCTURAL PROTEIN IN THE EPIDERMIS, HAVE BEEN CONSISTENTLY ASSOCIATED WITH AD, ESPECIALLY THE EARLY-ONSET PERSISTENT FORM OF DISEASE, AND ARE REGARDED AS THE MOST SIGNIFICANT KNOWN RISK FACTOR FOR AD DEVELOPMENT TO DATE. ADDITIONALLY, VARIATION IN SOME OTHER GENES INVOLVED IN SKIN INTEGRITY AND BARRIER FUNCTION HAVE SHOWN ASSOCIATION WITH AD. HOWEVER, THE KNOWN GENETIC RISK FACTORS CAN ONLY EXPLAIN A SMALL PART OF THE HERITABILITY AT THE MOMENT. WHOLE-EXOME OR WHOLE-GENOME SEQUENCING STUDIES HAVE NOT BEEN REPORTED YET, BUT WILL PROBABLY SOON EVALUATE THE INFLUENCE OF RARE VARIATIONS FOR AD DEVELOPMENT. ADDITIONALLY, LARGE MULTI-CENTRE STUDIES COMPREHENSIVELY INCORPORATING GENE-GENE AND GENE-ENVIRONMENT INTERACTIONS AS WELL AS EPIGENETIC MECHANISMS MIGHT FURTHER ELUCIDATE THE GENETIC FACTORS UNDERLYING AD PATHOGENESIS AND, THUS, OPEN THE WAY FOR A MORE INDIVIDUALIZED TREATMENT IN THE FUTURE. 2015 3 3104 44 GENOMIC, EPIGENOMIC, TRANSCRIPTOMIC, PROTEOMIC AND METABOLOMIC APPROACHES IN ATOPIC DERMATITIS. ATOPIC DERMATITIS (AD) IS A CHRONIC INFLAMMATORY SKIN DISEASE WITH A HIGH PREVALENCE IN THE DEVELOPED COUNTRIES. IT IS ASSOCIATED WITH ATOPIC AND NON-ATOPIC DISEASES, AND ITS CLOSE CORRELATION WITH ATOPIC COMORBIDITIES HAS BEEN GENETICALLY DEMONSTRATED. ONE OF THE MAIN ROLES OF GENETIC STUDIES IS TO COMPREHEND THE DEFECTS OF THE CUTANEOUS BARRIER DUE TO FILAGGRIN DEFICIT AND EPIDERMAL SPONGIOSIS. RECENTLY, EPIGENETIC STUDIES STARTED TO ANALYZE THE INFLUENCE OF THE ENVIRONMENTAL FACTORS ON GENE EXPRESSION. THE EPIGENOME IS CONSIDERED TO BE A SUPERIOR SECOND CODE THAT CONTROLS THE GENOME, WHICH INCLUDES ALTERATIONS OF THE CHROMATIN. THE EPIGENETIC CHANGES DO NOT ALTER THE GENETIC CODE, HOWEVER, CHANGES IN THE CHROMATIN STRUCTURE COULD ACTIVATE OR INHIBIT THE TRANSCRIPTION PROCESS OF CERTAIN GENES AND CONSEQUENTLY, THE TRANSLATION PROCESS OF THE NEW MRNA INTO A POLYPEPTIDE CHAIN. IN-DEPTH ANALYSIS OF THE TRANSCRIPTOMIC, METABOLOMIC AND PROTEOMIC STUDIES ALLOW TO UNRAVEL DETAILED MECHANISMS THAT CAUSE AD. THE EXTRACELLULAR SPACE AND LIPID METABOLISM ARE ASSOCIATED WITH AD THAT IS INDEPENDENT OF THE FILAGGRIN EXPRESSION. ON THE OTHER HAND, AROUND 45 PROTEINS ARE CONSIDERED AS THE PRINCIPAL COMPONENTS IN THE ATOPIC SKIN. MOREOVER, GENETIC STUDIES BASED ON THE DISRUPTED CUTANEOUS BARRIER CAN LEAD TO THE DEVELOPMENT OF NEW TREATMENTS TARGETING THE CUTANEOUS BARRIER OR CUTANEOUS INFLAMMATION. UNFORTUNATELY, AT PRESENT, THERE ARE NO TARGET THERAPIES THAT FOCUS ON THE EPIGENETIC PROCESS OF AD. HOWEVER, IN THE FUTURE, MIR-143 COULD BE AN IMPORTANT OBJECTIVE FOR NEW THERAPIES, AS IT TARGETS THE MIR-335:SOX AXIS, THEREBY RESTORING THE MIR-335 EXPRESSION, AND REPAIRING THE CUTANEOUS BARRIER DEFECTS. 2023 4 822 38 CHARACTERIZATION OF BLOOD SURROGATE IMMUNE-METHYLATION BIOMARKERS FOR IMMUNE CELL INFILTRATION IN CHRONIC INFLAMMAGING DISORDERS. ALZHEIMER'S DISEASE (AD) AND ATHEROSCLEROSIS ARE BOTH CHRONIC AGE- AND INFLAMMATION-DEPENDENT DISEASES. IN ADDITION, ATHEROSCLEROSIS IS FREQUENTLY OBSERVED IN AD PATIENTS INDICATING COMMON INVOLVEMENT OF VASCULAR COMPONENTS IN BOTH DISEASE ETIOLOGIES. RECENTLY, EPIGENOME-WIDE ASSOCIATION STUDIES HAVE IDENTIFIED EPIGENETIC ALTERATIONS, AND IN PARTICULARLY DNA METHYLATION CHANGES FOR BOTH DISORDERS. WE HYPOTHESIZED THE EXISTENCE OF A COMMON DNA METHYLATION PROFILE IN ATHEROSCLEROSIS AND AD WHICH MAY BE VALUABLE AS A BLOOD-BASED DNA METHYLATION INFLAMMAGING BIOMARKER. USING PUBLICLY AVAILABLE 450K ILLUMINA METHYLATION DATASETS, WE IDENTIFIED A CO-METHYLATION NETWORK ASSOCIATED WITH BOTH ATHEROSCLEROSIS AND AD IN WHOLE BLOOD SAMPLES. THIS METHYLATION PROFILE APPEARED TO INDICATE SHIFTS IN BLOOD IMMUNE CELL TYPE DISTRIBUTION. REMARKABLY, SIMILAR METHYLATION CHANGES WERE ALSO DETECTED IN DISEASE TISSUES, INCLUDING AD BRAIN TISSUES, ATHEROSCLEROTIC PLAQUES, AND TUMORS AND WERE FOUND TO CORRELATE WITH IMMUNE CELL INFILTRATION. IN ADDITION, THIS IMMUNE-RELATED METHYLATION PROFILE COULD ALSO BE DETECTED IN OTHER INFLAMMAGING DISEASES, INCLUDING PARKINSON'S DISEASE AND OBESITY, BUT NOT IN MULTIPLE SCLEROSIS, SCHIZOPHRENIA, AND OSTEOPOROSIS. IN CONCLUSION, WE IDENTIFIED A BLOOD-BASED IMMUNE-RELATED DNA METHYLATION SIGNATURE IN MULTIPLE INFLAMMAGING DISEASES ASSOCIATED WITH CHANGES IN BLOOD IMMUNE CELL COUNTS AND PREDICTIVE FOR IMMUNE CELL INFILTRATION IN DISEASED TISSUES. IN ADDITION TO EPIGENETIC CLOCK MEASUREMENTS, THIS IMMUNE-METHYLATION SIGNATURE MAY BECOME A VALUABLE BLOOD-BASED BIOMARKER TO PREVENT CHRONIC INFLAMMATORY DISEASE DEVELOPMENT OR MONITOR LIFESTYLE INTERVENTION STRATEGIES WHICH PROMOTE HEALTHY AGING. 2019 5 2920 46 GENE-SET ANALYSIS IS SEVERELY BIASED WHEN APPLIED TO GENOME-WIDE METHYLATION DATA. MOTIVATION: DNA METHYLATION IS AN EPIGENETIC MARK THAT CAN STABLY REPRESS GENE EXPRESSION. BECAUSE OF ITS BIOLOGICAL AND CLINICAL SIGNIFICANCE, SEVERAL METHODS HAVE BEEN DEVELOPED TO COMPARE GENOME-WIDE PATTERNS OF METHYLATION BETWEEN GROUPS OF SAMPLES. THE APPLICATION OF GENE SET ANALYSIS TO IDENTIFY RELEVANT GROUPS OF GENES THAT ARE ENRICHED FOR DIFFERENTIALLY METHYLATED GENES IS OFTEN A MAJOR COMPONENT OF THE ANALYSIS OF THESE DATA. THIS CAN BE USED, FOR EXAMPLE, TO IDENTIFY PROCESSES OR PATHWAYS THAT ARE PERTURBED IN DISEASE DEVELOPMENT. WE SHOW THAT GENE-SET ANALYSIS, AS IT IS TYPICALLY APPLIED TO GENOME-WIDE METHYLATION ASSAYS, IS SEVERELY BIASED AS A RESULT OF DIFFERENCES IN THE NUMBERS OF CPG SITES ASSOCIATED WITH DIFFERENT CLASSES OF GENES AND GENE PROMOTERS. RESULTS: WE DEMONSTRATE THIS BIAS USING PUBLISHED DATA FROM A STUDY OF DIFFERENTIAL CPG ISLAND METHYLATION IN LUNG CANCER AND A DATASET WE GENERATED TO STUDY METHYLATION CHANGES IN PATIENTS WITH LONG-STANDING ULCERATIVE COLITIS. WE SHOW THAT SEVERAL OF THE GENE SETS THAT SEEM ENRICHED WOULD ALSO BE IDENTIFIED WITH RANDOMIZED DATA. WE SUGGEST TWO EXISTING APPROACHES THAT CAN BE ADAPTED TO CORRECT THE BIAS. ACCOUNTING FOR THE BIAS IN THE LUNG CANCER AND ULCERATIVE COLITIS DATASETS PROVIDES NOVEL BIOLOGICAL INSIGHTS INTO THE ROLE OF METHYLATION IN CANCER DEVELOPMENT AND CHRONIC INFLAMMATION, RESPECTIVELY. OUR RESULTS HAVE SIGNIFICANT IMPLICATIONS FOR MANY PREVIOUS GENOME-WIDE METHYLATION STUDIES THAT HAVE DRAWN CONCLUSIONS ON THE BASIS OF SUCH STRONGLY BIASED ANALYSIS. CONTACT: CATHAL.SEOIGHE@NUIGALWAY.IE SUPPLEMENTARY INFORMATION: SUPPLEMENTARY DATA ARE AVAILABLE AT BIOINFORMATICS ONLINE. 2013 6 2064 36 EPIGENETIC CONTROL OF INFLAMMATION IN ATOPIC DERMATITIS. ATOPIC DERMATITIS (AD), ALSO KNOWN AS ATOPIC ECZEMA, IS A COMMON BUT ALSO COMPLEX CHRONIC, ITCHY SKIN CONDITION WITH UNDERLYING INFLAMMATION OF THE SKIN. THIS SKIN AILMENT IS PREVALENT WORLDWIDE AND AFFECTS PEOPLE OF ALL AGES, PARTICULARLY CHILDREN BELOW FIVE YEARS OF AGE. THE ITCHING AND RESULTING RASHES IN AD PATIENTS ARE OFTEN THE RESULT OF INFLAMMATORY SIGNALS, THUS NECESSITATING A CLOSER LOOK AT THE INFLAMMATION-REGULATING MECHANISMS FOR PUTATIVE RELIEF, CARE AND THERAPY. SEVERAL CHEMICAL- AS WELL AS GENETICALLY-INDUCED ANIMAL MODELS HAVE ESTABLISHED THE IMPORTANCE OF TARGETING PRO-INFLAMMATORY AD MICROENVIRONMENT. EPIGENETIC MECHANISMS ARE GAINING ATTENTION TOWARDS A BETTER UNDERSTANDING OF THE ONSET AS WELL AS THE PROGRESSION OF INFLAMMATION. SEVERAL PHYSIOLOGICAL PROCESSES WITH IMPLICATIONS IN PATHOPHYSIOLOGY OF AD, SUCH AS, BARRIER DYSFUNCTION EITHER DUE TO REDUCED FILAGGRIN / HUMAN BETA-DEFENSINS OR ALTERED MICROBIOME, REPROGRAMING OF FC RECEPTORS WITH RESULTING OVEREXPRESSION OF HIGH AFFINITY IGE RECEPTORS, ELEVATED EOSINOPHIL NUMBERS OR THE ELEVATED IL-22 PRODUCTION BY CD4 + T CELLS HAVE UNDERLYING EPIGENETIC MECHANISMS THAT INCLUDE DIFFERENTIAL PROMOTER METHYLATION AND/OR REGULATION BY NON-CODING RNAS. REVERSING THESE EPIGENETIC CHANGES HAS BEEN VERIFIED TO REDUCE INFLAMMATORY BURDEN THROUGH ALTERED SECRETION OF CYTOKINES IL-6, IL-4, IL-13, IL-17, IL-22 ETC, WITH BENEFIT AGAINST AD PROGRESSION IN EXPERIMENTAL MODELS. A THOROUGH UNDERSTANDING OF EPIGENETIC REMODELING OF INFLAMMATION IN AD HAS THE POTENTIAL OF OPENING AVENUES FOR NOVEL DIAGNOSTIC, PROGNOSTIC AND THERAPEUTIC OPTIONS. 2023 7 4961 46 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 8 3026 43 GENETICS OF BEHCET'S DISEASE: FUNCTIONAL GENETIC ANALYSIS AND ESTIMATING DISEASE HERITABILITY. BEHCET'S DISEASE IS A CHRONIC MULTISYSTEMIC INFLAMMATORY DISORDER CHARACTERIZED BY RECURRENT ORAL AND GENITAL ULCERS. ALTHOUGH ITS ETIOLOGY REMAINS UNCLEAR, IT IS THOUGHT THAT BOTH GENETIC AND ENVIRONMENTAL FACTORS CONTRIBUTE TO THE ONSET AND PROGRESSION OF BEHCET'S DISEASE. HERE, WE PROVIDE AN UPDATED VIEW OF THE GENETIC LANDSCAPE AND ARCHITECTURE OF BEHCET'S DISEASE. LARGE-SCALE GENETIC STUDIES PERFORMED TO DATE REVEALED 21 GENETIC SUSCEPTIBILITY LOCI ASSOCIATED WITH THE DISEASE AT A GWAS LEVEL OF SIGNIFICANCE (P-VALUE = 5 X 10(-8)). WE PERFORMED EPIGENETIC PATTERN ENRICHMENT ANALYSIS IN BEHCET'S DISEASE ASSOCIATED LOCI, PROVIDING NEW INSIGHTS INTO THE MOLECULAR MECHANISMS UNDERLYING ITS PATHOPHYSIOLOGY. OUR DATA SUGGEST THE CRUCIAL INVOLVEMENT OF SEVERAL IMMUNE CELL TYPES, INCLUDING NATURAL KILLER CELLS, MONOCYTES, AND B CELLS IN THE PATHOGENESIS OF THE DISEASE. PATHWAY ENRICHMENT ANALYSIS IDENTIFIED IMPORTANT BIOLOGICAL PROCESSES INVOLVED. USING LARGE-SCALE GENETIC DATA AVAILABLE FROM ~200 IMMUNE-RELATED LOCI (IMMUNOCHIP), WE ESTIMATE BEHCET'S DISEASE HERITABILITY TO BE AT LEAST 16%. WE FURTHER USED THE SAME APPROACH TO ESTIMATE THE HERITABILITY EXPLAINED BY THE KNOWN BEHCET'S DISEASE-ASSOCIATED LOCI, SUGGESTING THAT THEY EXPLAIN ~ 60% OF THE GENETIC COMPONENT UNDERLYING BEHCET'S DISEASE. THESE RESULTS INDICATE A SIGNIFICANT ROLE OF NON-GENETIC FACTORS IN CAUSING BEHCET'S DISEASE AND THAT ADDITIONAL GENETIC VARIATION INFLUENCING THE RISK OF BEHCET'S DISEASE REMAINS TO BE IDENTIFIED. FINALLY, WE CALCULATED A CUMULATIVE GENETIC RISK SCORE ACROSS POPULATIONS REINFORCING THE LINK BETWEEN GEOGRAPHIC VARIATIONS IN DISEASE PREVALENCE WITH ITS GENETIC COMPONENT. 2021 9 2797 31 FCER1G GENE HYPOMETHYLATION IN PATIENTS WITH RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC AUTOIMMUNE DISEASE THAT, WHEN IMPROPERLY TREATED, LEADS TO DISABILITY IN PATIENTS. VARIOUS FACTORS THAT MAY CAUSE THE DEVELOPMENT AND ACTIVITY OF RA ARE BEING CONSIDERED. EPIGENETIC FACTORS ARE ALSO RECEIVING INCREASING ATTENTION. IN OUR STUDY, WE ANALYZED THE ASSOCIATION BETWEEN FCER1G GENE METHYLATION AND RA ACTIVITY. WE CONDUCTED OUR STUDY IN 50 RA PATIENTS AND 24 CONTROLS. THE PATIENTS WERE DIVIDED INTO TWO GROUPS IN TERMS OF HIGH DISEASE ACTIVITY AND REMISSION. QUANTITATIVE REAL-TIME METHYLATION-SPECIFIC PCR WAS USED TO ANALYZE THE METHYLATION STATUS OF THE INVESTIGATED GENES. WE OBSERVED THAT RA PATIENTS HAVE LOWER LEVELS OF METHYLATION OF THE FCER1G GENE COMPARED TO CONTROLS, BUT WE DID NOT FIND ANY DIFFERENCE IN THE METHYLATION STATUS OF THIS GENE BETWEEN PATIENTS WITH HIGH DISEASE ACTIVITY AND REMISSION. THE RESULTS OF THIS STUDY SUGGEST THAT FCER1G GENE METHYLATION MAY BE A NEW POTENTIAL EPIGENETIC MARKER OF RA THAT IS INDEPENDENT OF DISEASE ACTIVITY. 2022 10 4228 32 METHYLATION OF INFLAMMATORY CELLS IN LUNG DISEASES. THIS CHAPTER OVERVIEWS ROLES OF DNA METHYLATION IN INFLAMMATORY CELL BIOLOGY WITH THE FOCUSES ON LYMPHOCYTES AND MACROPHAGES/MONOCYTES IN LUNG DISEASES, ALTHOUGH THE MOLECULAR MECHANISMS BY WHICH TARGET GENES ARE METHYLATED AND REGULATED IN LUNG DISEASES REMAIN UNCLEAR. MOST OF EPIGENETIC STUDIES ON DNA METHYLATION OF TARGET GENES IN LUNG DISEASES MAINLY DEMONSTRATED THE CORRELATION OF DNA METHYLATION OF TARGET GENES WITH THE LEVELS OF OTHER CORRESPONDING FACTORS, WITH THE SPECIFICITY OF CLINICAL PHENOMES, AND WITH THE SEVERITY OF LUNG DISEASES. THERE IS AN URGENT NEED TO IDENTIFY AND VALIDATE THE SPECIFICITY AND REGULATORY MECHANISMS OF INFLAMMATORY CELL EPIGENETICS IN DEPTH. THE EPIGENETIC HETEROGENEITY AMONG DIFFERENT SUBSETS OF T CELLS AND AMONG PROMOTERS OR NON-PROMOTERS OF TARGET GENES SHOULD BE FURTHERMORE CLARIFIED IN ACUTE OR CHRONIC LUNG DISEASES AND CANCERS. THE HYPER/HYPO-METHYLATION AND MODIFICATIONS OF CHROMOSOL AND EXTRACHROMOSOMAL DNA MAY RESULT IN ALTERNATIONS IN PROTEINS WITHIN INFLAMMATORY CELLS, WHICH CAN BE IDENTIFIED AS DISEASE-SPECIFIC BIOMARKERS AND THERAPEUTIC TARGETS. 2020 11 3765 50 INTEGRATIVE ANALYSIS OF TRANSCRIPTOMIC AND PROTEOMIC PROFILING IN INFLAMMATORY BOWEL DISEASE COLON BIOPSIES. BACKGROUND: CROHN'S DISEASE (CD) AND ULCERATIVE COLITIS (UC) ARE INTESTINAL CHRONIC INFLAMMATORY CONDITIONS CHARACTERIZED BY ALTERED EPITHELIAL BARRIER FUNCTION AND TISSUE DAMAGE. DESPITE SIGNIFICANT EFFORTS TO UNDERSTANDING THE BIOLOGICAL MECHANISMS RESPONSIBLE FOR GUT INFLAMMATION, THE PATHOPHYSIOLOGY OF CD AND UC REMAINS POORLY UNDERSTOOD. METHODS: TO HELP ELUCIDATE THE POTENTIAL MECHANISMS RESPONSIBLE FOR GUT INFLAMMATION IN CD AND UC, TRANSCRIPTOMIC AND PROTEOMIC PROFILING OF HUMAN COLON BIOPSY SPECIMENS WAS PERFORMED. DYSREGULATED GENES AND PROTEINS IN DISEASE TISSUES COMPARED WITH NORMAL TISSUES WERE CHARACTERIZED FROM THE EXPRESSION PROFILES AND FURTHER SUBJECTED TO PATHWAY ANALYSIS TO IDENTIFY ALTERED BIOLOGICAL PROCESSES AND SIGNALING PATHWAYS. RESULTS: SAMPLE ANALYSIS SHOWED 4250 GENES WITH MATCHED PROTEIN EXPRESSION AND A WIDE RANGE OF CORRELATION OF RNA-PROTEIN ABUNDANCE ACROSS SAMPLES. PATHWAY ANALYSIS OF DYSREGULATED GENES AND PROTEINS IN CD AND UC SHOWED ALTERATIONS IN IMMUNE AND INFLAMMATORY RESPONSES, COMPLEMENT CASCADE, AND THE SUPPRESSION OF METABOLIC PROCESSES AND PPAR SIGNALING. IN CD, INCREASED T-HELPER CELL DIFFERENTIATION AND ELEVATED TOLL-LIKE RECEPTOR AND JAK/STAT SIGNALING WERE OBSERVED. INTERESTINGLY, INCREASED MAPK SIGNALING WAS ONLY OBSERVED IN UC. WEIGHTED GENE CO-EXPRESSION NETWORK ANALYSIS SUGGESTED A POSSIBLE ROLE OF EPIGENETIC REGULATION IN UC. OF NOTE, A LARGE DISCREPANCY BETWEEN REGULATION OF RNA AND PROTEIN LEVELS IN INFLAMED COLON SAMPLES WAS DETECTED FOR PREVIOUSLY IDENTIFIED BIOMARKERS INCLUDING MMP14 AND LAMP1. CONCLUSIONS: WITH THE ANALYSIS OF DYSREGULATED GENES AND PATHWAYS, THE PRESENT STUDY UNRAVELS KEY MECHANISMS CONTRIBUTING TO CD AND UC PATHOGENESIS AND EMPHASIZES THAT INTEGRATIVE ANALYSIS OF MULTI-OMICS DATA SETS CAN PROVIDE MORE INSIGHT INTO UNDERSTANDING COMPLEX DISEASE MECHANISMS. 2019 12 2483 36 EPIGENETIC VARIATION AND HUMAN DISEASE. CYTOSINE GUANINE DINUCLEOTIDE (CPG) ISLAND METHYLATION IS A KNOWN MECHANISM OF EPIGENETIC INHERITANCE IN POSTMEIOTIC CELLS. THROUGH ASSOCIATED CHROMATIN CHANGES AND SILENCING, SUCH EPIGENETIC STATES CAN INFLUENCE CELLULAR PHYSIOLOGY AND AFFECT DISEASE RISK AND SEVERITY. OUR STUDIES OF CPG ISLAND METHYLATION IN NORMAL COLORECTAL MUCOSA REVEALED PROGRESSIVE AGE-RELATED INCREASES AT MULTIPLE GENE LOCI, SUGGESTING GENOME-WIDE MOLECULAR ALTERATIONS WITH POTENTIAL TO SILENCE GENE EXPRESSION. HOWEVER, THERE WAS CONSIDERABLE VARIATION IN THE DEGREE OF METHYLATION AMONG INDIVIDUALS OF COMPARABLE AGES. SUCH VARIATION COULD BE RELATED TO GENETIC FACTORS, LIFESTYLE, OR ENVIRONMENTAL EXPOSURES. STUDIES IN ULCERATIVE COLITIS AND HEPATOCELLULAR CIRRHOSIS AND NEOPLASIA REVEALED THAT CHRONIC INFLAMMATORY STATES ARE ACCOMPANIED BY MARKED INCREASES IN CPG ISLAND METHYLATION IN NORMAL-APPEARING TISSUES, CONFIRMING THE HYPOTHESIS THAT PROINFLAMMATORY EXPOSURES COULD ACCOUNT FOR PART OF THE EPIGENETIC VARIATION IN HUMAN POPULATIONS. PRELIMINARY DATA ALSO SUGGEST POTENTIAL INFLUENCES OF LIFESTYLE AND EXPOSURE FACTORS ON CPG ISLAND METHYLATION. IT IS SUGGESTED THAT EPIGENETIC VARIATION RELATED TO AGING, LIFESTYLE, EXPOSURES AND POSSIBLY GENETIC FACTORS, IS ONE OF THE MODULATORS OF ACQUIRED, AGE-RELATED HUMAN DISEASES, INCLUDING NEOPLASIA. 2002 13 287 29 AGING AND CHRONIC SUN EXPOSURE CAUSE DISTINCT EPIGENETIC CHANGES IN HUMAN SKIN. EPIGENETIC CHANGES ARE WIDELY CONSIDERED TO PLAY AN IMPORTANT ROLE IN AGING, BUT EXPERIMENTAL EVIDENCE TO SUPPORT THIS HYPOTHESIS HAS BEEN SCARCE. WE HAVE USED ARRAY-BASED ANALYSIS TO DETERMINE GENOME-SCALE DNA METHYLATION PATTERNS FROM HUMAN SKIN SAMPLES AND TO INVESTIGATE THE EFFECTS OF AGING, CHRONIC SUN EXPOSURE, AND TISSUE VARIATION. OUR RESULTS REVEAL A HIGH DEGREE OF TISSUE SPECIFICITY IN THE METHYLATION PATTERNS AND ALSO SHOWED VERY LITTLE INTERINDIVIDUAL VARIATION WITHIN TISSUES. DATA STRATIFICATION BY AGE REVEALED THAT DNA FROM OLDER INDIVIDUALS WAS CHARACTERIZED BY A SPECIFIC HYPERMETHYLATION PATTERN AFFECTING LESS THAN 1% OF THE MARKERS ANALYZED. INTERESTINGLY, STRATIFICATION BY SUN EXPOSURE PRODUCED A FUNDAMENTALLY DIFFERENT PATTERN WITH A SIGNIFICANT TREND TOWARDS HYPOMETHYLATION. OUR RESULTS THUS IDENTIFY DEFINED AGE-RELATED DNA METHYLATION CHANGES AND SUGGEST THAT THESE ALTERATIONS MIGHT CONTRIBUTE TO THE PHENOTYPIC CHANGES ASSOCIATED WITH SKIN AGING. 2010 14 3503 35 IDENTIFICATION OF POTENTIAL DIFFERENTIALLY METHYLATED GENE-RELATED BIOMARKERS IN ENDOMETRIOSIS. AIM: TO IDENTIFY EPIGENETIC ALTERATIONS OF DIFFERENTIALLY EXPRESSED GENES AND SCREEN OUT TARGETED THERAPEUTIC DRUGS IN ENDOMETRIOSIS. METHODS: BASED ON THE GENE EXPRESSION OMNIBUS DATABASE AND A SERIES OF BIOLOGICAL INFORMATION ANALYSIS TOOLS, SUPPLEMENTED BY VALIDATION OF CLINICAL SAMPLES, ABERRANT DNA METHYLATION-DRIVEN GENES AND THEIR FUNCTIONS WERE EXPLORED, AS WELL AS POSSIBLE TARGETED DRUGS. RESULTS: THIS STUDY SCREENED OUT A RANGE OF DNA METHYLATION-DRIVEN GENES THAT WERE ASSOCIATED WITH POWERFUL PROPERTIES AND CORRESPONDING PATHWAYS. AMONG THEM, BDNF AND CCL2 WERE KEY GENES IN THE DEVELOPMENT OF ENDOMETRIOSIS. FOUR CHEMICAL AGENTS HAVE BEEN FLAGGED AS POTENTIAL TREATMENTS FOR ENDOMETRIOSIS. CONCLUSION: THESE CANDIDATE GENES AND SMALL-MOLECULE AGENTS MAY BE FURTHER EXPLORED AS POTENTIAL TARGETS AND DRUGS FOR ENDOMETRIOSIS DIAGNOSIS AND THERAPY, RESPECTIVELY. 2022 15 1508 54 DNA METHYLATION AND MRNA AND MICRORNA EXPRESSION OF SLE CD4+ T CELLS CORRELATE WITH DISEASE PHENOTYPE. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IS AN AUTOIMMUNE DISEASE WELL KNOWN FOR ITS CLINICAL HETEROGENEITY, AND ITS ETIOLOGY SECONDARY TO A CROSS-TALK INVOLVING GENETIC PREDISPOSITION AND ENVIRONMENTAL STIMULI. ALTHOUGH GENOME-WIDE ANALYSIS HAS CONTRIBUTED GREATLY TO OUR UNDERSTANDING OF THE GENETIC BASIS OF SLE, THERE IS INCREASING EVIDENCE FOR A ROLE OF EPIGENETICS. INDEED, RECENT DATA HAVE DEMONSTRATED THAT IN PATIENTS WITH SLE, THERE ARE STRIKING ALTERATIONS OF DNA METHYLATION, HISTONE MODIFICATIONS, AND DEREGULATED MICRORNA EXPRESSION, THE SUM OF WHICH CONTRIBUTE TO OVER-EXPRESSION OF SELECT AUTOIMMUNE-RELATED GENES AND LOSS OF TOLERANCE. TO ADDRESS THIS ISSUE AT THE LEVEL OF CLINICAL PHENOTYPE, WE PERFORMED DNA METHYLATION, MRNA AND MICRORNA EXPRESSION SCREENING USING HIGH-THROUGHPUT SEQUENCING OF PURIFIED CD4+ T CELLS FROM PATIENTS WITH SLE, COMPARED TO AGE AND SEX MATCHED CONTROLS. IN PARTICULAR, WE STUDIED 42 PATIENTS WITH SLE AND DIVIDED THIS GROUP INTO THREE CLINICAL PHENOTYPES: A) THE PRESENCE OF SKIN LESIONS WITHOUT SIGNS OF SYSTEMIC PATHOLOGY; B) SKIN LESIONS BUT ALSO CHRONIC RENAL PATHOLOGY; AND C) SKIN LESIONS, CHRONIC RENAL PATHOLOGY AND POLYARTICULAR DISEASE. INTERESTINGLY, AND AS EXPECTED, SEQUENCING DATA REVEALED CHANGES IN DNA METHYLATION IN SLE COMPARED TO CONTROLS. HOWEVER, AND MORE IMPORTANTLY, ALTHOUGH THERE WERE COMMON METHYLATION CHANGES FOUND IN ALL GROUPS OF SLE COMPARED TO CONTROLS, THERE WAS SPECIFIC DNA METHYLATION CHANGES THAT CORRELATED WITH CLINICAL PHENOTYPE. THESE INCLUDED CHANGES IN THE NOVEL KEY TARGET GENES NLRP2, CD300LB AND S1PR3, AS WELL AS CHANGES IN THE CRITICAL PATHWAYS, INCLUDING THE ADHERENS JUNCTION AND LEUKOCYTE TRANSENDOTHELIAL MIGRATION. WE ALSO NOTED THAT A SIGNIFICANT PROPORTION OF GENES UNDERGOING DNA METHYLATION CHANGES WERE INVERSELY CORRELATED WITH GENE EXPRESSION AND THAT MIRNA SCREENING REVEALED THE EXISTENCE OF SUBSETS WITH CHANGES IN EXPRESSION. INTEGRATED ANALYSIS OF THIS DATA HIGHLIGHTS SPECIFIC SETS OF MIRNAS CONTROLLED BY DNA METHYLATION, AND GENES THAT ARE ALTERED BY METHYLATION AND TARGETED BY MIRNAS. IN CONCLUSION, OUR FINDINGS SUGGEST SELECT EPIGENETIC MECHANISMS THAT CONTRIBUTE TO CLINICAL PHENOTYPES AND FURTHER SHED LIGHT ON A NEW VENUE FOR BASIC SLE RESEARCH. 2014 16 2909 44 GENE EXPRESSION PROFILING IN FIBROMYALGIA INDICATES AN AUTOIMMUNE ORIGIN OF THE DISEASE AND OPENS NEW AVENUES FOR TARGETED THERAPY. FIBROMYALGIA IS A CHRONIC DISORDER CHARACTERIZED BY WIDESPREAD PAIN AND BY SEVERAL NON-PAIN SYMPTOMS. AUTOIMMUNITY, SMALL FIBER NEUROPATHY AND NEUROINFLAMMATION HAVE BEEN SUGGESTED TO BE INVOLVED IN THE PATHOGENESIS OF THE DISEASE. WE HAVE INVESTIGATED THE GENE EXPRESSION PROFILE IN PERIPHERAL BLOOD MONONUCLEAR CELLS OBTAINED FROM TEN PATIENTS AND TEN HEALTHY SUBJECTS. OF THE 545,500 TRANSCRIPTS ANALYZED, 1673 RESULTED MODULATED IN FIBROMYALGIC PATIENTS. THE MAJORITY OF THESE GENES ARE INVOLVED IN BIOLOGICAL PROCESSES AND PATHWAYS LINKED TO THE CLINICAL MANIFESTATIONS OF THE DISEASE. MOREOVER, GENES INVOLVED IN IMMUNOLOGICAL PATHWAYS CONNECTED TO INTERLEUKIN-17 AND TO TYPE I INTERFERON SIGNATURES WERE ALSO MODULATED, SUGGESTING THAT AUTOIMMUNITY PLAYS A ROLE IN THE DISEASE. WE THEN AIMED AT IDENTIFYING DIFFERENTIALLY EXPRESSED LONG NON-CODING RNAS (LNCRNAS) FUNCTIONALLY CONNECTED TO MODULATED GENES BOTH DIRECTLY AND VIA MICRORNA TARGETING. ONLY TWO LNCRNAS OF THE 298 FOUND MODULATED IN PATIENTS, WERE ABLE TO TARGET THE MOST HIGHLY CONNECTED GENES IN THE FIBROMYALGIA INTERACTOME, SUGGESTING THEIR INVOLVEMENT IN CRUCIAL GENE REGULATION. OUR GENE EXPRESSION DATA WERE CONFIRMED BY REAL TIME PCR, BY AUTOANTIBODY TESTING, DETECTION OF SOLUBLE MEDIATORS AND TH-17 POLARIZATION IN A VALIDATION COHORT OF 50 PATIENTS. OUR RESULTS INDICATE THAT GENETIC AND EPIGENETIC MECHANISMS AS WELL AS AUTOIMMUNITY PLAY A PIVOTAL ROLE IN THE PATHOGENESIS OF FIBROMYALGIA. 2020 17 6158 66 THE GENETICS AND EPIGENETICS OF ATOPIC DERMATITIS-FILAGGRIN AND OTHER POLYMORPHISMS. ATOPIC DERMATITIS (AD) IS A CHRONIC INFLAMMATORY SKIN DISEASE CAUSED BY A COMBINATION OF GENETIC AND ENVIRONMENTAL FACTORS. GENETIC EVIDENCES DEPICT A COMPLEX NETWORK COMPRISING BY EPIDERMAL BARRIER DYSFUNCTIONS AND DYSREGULATION OF INNATE AND ADAPTIVE IMMUNITY IN THE PATHOGENESIS OF AD. MUTATIONS IN THE HUMAN FILAGGRIN GENE (FLG) ARE THE MOST SIGNIFICANT AND WELL-REPLICATED GENETIC MUTATION ASSOCIATED WITH AD, AND OTHER MUTATIONS ASSOCIATED WITH EPIDERMAL BARRIERS SUCH AS SPINK5, FLG-2, SPRR3, AND CLDN1 HAVE ALL BEEN LINKED TO AD. GENE VARIANTS MAY ALSO CONTRIBUTE TO THE ABNORMAL INNATE AND ADAPTIVE RESPONSES FOUND IN AD, INCLUDING MUTATIONS IN PRRS AND AMPS, TSLP AND TSLPR, IL-1 FAMILY CYTOKINES AND RECEPTORS GENES, VITAMIN D PATHWAY GENES, FCER1A, AND TH2 AND OTHER CYTOKINES GENES. GWAS AND IMMUNOCHIP ANALYSIS HAVE IDENTIFIED A TOTAL OF 19 SUSCEPTIBILITY LOCI FOR AD. CANDIDATE GENES AT THESE SUSCEPTIBILITY LOCI IDENTIFIED BY GWAS AND IMMUNOCHIP ANALYSIS ALSO SUGGEST ROLES FOR EPIDERMAL BARRIER FUNCTIONS, INNATE AND ADAPTIVE IMMUNITY, INTERLEUKIN-1 FAMILY SIGNALING, REGULATORY T CELLS, THE VITAMIN D PATHWAY, AND THE NERVE GROWTH FACTOR PATHWAY IN THE PATHOGENESIS OF AD. INCREASING EVIDENCES SHOW THE MODERN LIFESTYLE (I.E., THE HYGIENE HYPOTHESIS, WESTERN DIET) AND OTHER ENVIRONMENTAL FACTORS SUCH AS POLLUTION AND ENVIRONMENTAL TOBACCO SMOKE (ETS) LEAD TO THE INCREASING PREVALENCE OF AD WITH THE DEVELOPMENT OF INDUSTRIALIZATION. EPIGENETIC ALTERATIONS IN RESPONSE TO THESE ENVIRONMENTAL FACTORS, INCLUDING DNA METHYLATION AND MICRORNA RELATED TO IMMUNE SYSTEM AND SKIN BARRIERS, HAVE BEEN FOUND TO CONTRIBUTE TO THE PATHOGENESIS OF AD. GENETIC VARIANTS AND EPIGENETIC ALTERATION MIGHT BE THE KEY TOOLS FOR THE MOLECULAR TAXONOMY OF AD AND PROVIDE THE BACKGROUND FOR THE PERSONALIZED MANAGEMENT. 2016 18 6013 47 THE APPLICATIONS OF DNA METHYLATION AS A BIOMARKER IN KIDNEY TRANSPLANTATION: A SYSTEMATIC REVIEW. BACKGROUND: ALTHOUGH KIDNEY TRANSPLANTATION IMPROVES PATIENT SURVIVAL AND QUALITY OF LIFE, LONG-TERM RESULTS ARE HAMPERED BY BOTH IMMUNE- AND NON-IMMUNE-MEDIATED COMPLICATIONS. CURRENT BIOMARKERS OF POST-TRANSPLANT COMPLICATIONS, SUCH AS ALLOGRAFT REJECTION, CHRONIC RENAL ALLOGRAFT DYSFUNCTION, AND CUTANEOUS SQUAMOUS CELL CARCINOMA, HAVE A SUBOPTIMAL PREDICTIVE VALUE. DNA METHYLATION IS AN EPIGENETIC MODIFICATION THAT DIRECTLY AFFECTS GENE EXPRESSION AND PLAYS AN IMPORTANT ROLE IN PROCESSES SUCH AS ISCHEMIA/REPERFUSION INJURY, FIBROSIS, AND ALLOREACTIVE IMMUNE RESPONSE. NOVEL TECHNIQUES CAN QUICKLY ASSESS THE DNA METHYLATION STATUS OF MULTIPLE LOCI IN DIFFERENT CELL TYPES, ALLOWING A DEEP AND INTERESTING STUDY OF CELLS' ACTIVITY AND FUNCTION. THEREFORE, DNA METHYLATION HAS THE POTENTIAL TO BECOME AN IMPORTANT BIOMARKER FOR PREDICTION AND MONITORING IN KIDNEY TRANSPLANTATION. PURPOSE OF THE STUDY: THE AIM OF THIS STUDY WAS TO EVALUATE THE ROLE OF DNA METHYLATION AS A POTENTIAL BIOMARKER OF GRAFT SURVIVAL AND COMPLICATIONS DEVELOPMENT IN KIDNEY TRANSPLANTATION. MATERIAL AND METHODS: A SYSTEMATIC REVIEW OF SEVERAL DATABASES HAS BEEN CONDUCTED. THE NEWCASTLE-OTTAWA SCALE AND THE JADAD SCALE HAVE BEEN USED TO ASSESS THE RISK OF BIAS FOR OBSERVATIONAL AND RANDOMIZED STUDIES, RESPECTIVELY. RESULTS: TWENTY ARTICLES REPORTING ON DNA METHYLATION AS A BIOMARKER FOR KIDNEY TRANSPLANTATION WERE INCLUDED, ALL USING DNA METHYLATION FOR PREDICTION AND MONITORING. DNA METHYLATION PATTERN ALTERATIONS IN CELLS ISOLATED FROM DIFFERENT TISSUES, SUCH AS KIDNEY BIOPSIES, URINE, AND BLOOD, HAVE BEEN ASSOCIATED WITH ISCHEMIA-REPERFUSION INJURY AND CHRONIC RENAL ALLOGRAFT DYSFUNCTION. THESE ALTERATIONS OCCURRED IN DIFFERENT AND SPECIFIC LOCI. DNA METHYLATION STATUS HAS ALSO PROVED TO BE IMPORTANT FOR IMMUNE RESPONSE MODULATION, HAVING A CRUCIAL ROLE IN REGULATORY T CELL DEFINITION AND ACTIVITY. RESEARCH ALSO FOCUSED ON A BETTER UNDERSTANDING OF THE ROLE OF THIS EPIGENETIC MODIFICATION ASSESSMENT FOR REGULATORY T CELLS ISOLATION AND EXPANSION FOR FUTURE TOLERANCE INDUCTION-ORIENTED THERAPIES. CONCLUSIONS: STUDIES INCLUDED IN THIS REVIEW ARE HETEROGENEOUS IN STUDY DESIGN, BIOLOGICAL SAMPLES, AND OUTCOME. MORE COORDINATED INVESTIGATIONS ARE NEEDED TO AFFIRM DNA METHYLATION AS A CLINICALLY RELEVANT BIOMARKER IMPORTANT FOR PREVENTION, MONITORING, AND INTERVENTION. 2022 19 938 50 CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) RISK IS MEDIATED BY MULTIPLE ENHANCER VARIANTS WITHIN CLL RISK LOCI. CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS THE MOST COMMON ADULT LEUKEMIA IN WESTERN COUNTRIES. IT HAS A STRONG GENETIC BASIS, SHOWING A ~ 8-FOLD INCREASED RISK OF CLL IN FIRST-DEGREE RELATIVES. GENOME-WIDE ASSOCIATION STUDIES (GWAS) HAVE IDENTIFIED 41 RISK VARIANTS ACROSS 41 LOCI. HOWEVER, FOR A MAJORITY OF THE LOCI, THE FUNCTIONAL VARIANTS AND THE MECHANISMS UNDERLYING THEIR CAUSAL ROLES REMAIN UNDEFINED. HERE, WE EXAMINED THE GENETIC AND EPIGENETIC FEATURES ASSOCIATED WITH 12 INDEX VARIANTS, ALONG WITH ANY CORRELATED (R2 >/= 0.5) VARIANTS, AT THE CLL RISK LOCI LOCATED OUTSIDE OF GENE PROMOTERS. BASED ON PUBLICLY AVAILABLE CHIP-SEQ AND CHROMATIN ACCESSIBILITY DATA AS WELL AS OUR OWN CHIP-SEQ DATA FROM CLL PATIENTS, WE IDENTIFIED SIX CANDIDATE FUNCTIONAL VARIANTS AT SIX LOCI AND AT LEAST TWO CANDIDATE FUNCTIONAL VARIANTS AT EACH OF THE REMAINING SIX LOCI. THE FUNCTIONAL VARIANTS ARE PREDOMINANTLY LOCATED WITHIN ENHANCERS OR SUPER-ENHANCERS, INCLUDING BI-DIRECTIONALLY TRANSCRIBED ENHANCERS, WHICH ARE OFTEN RESTRICTED TO IMMUNE CELL TYPES. FURTHERMORE, WE FOUND THAT, AT 78% OF THE FUNCTIONAL VARIANTS, THE ALTERNATIVE ALLELES ALTERED THE TRANSCRIPTION FACTOR BINDING MOTIFS OR HISTONE MODIFICATIONS, INDICATING THE INVOLVEMENT OF THESE VARIANTS IN THE CHANGE OF LOCAL CHROMATIN STATE. FINALLY, THE ENHANCERS CARRYING FUNCTIONAL VARIANTS PHYSICALLY INTERACTED WITH GENES ENRICHED IN THE TYPE I INTERFERON SIGNALING PATHWAY, APOPTOSIS, OR TP53 NETWORK THAT ARE KNOWN TO PLAY KEY ROLES IN CLL. THESE RESULTS SUPPORT THE REGULATORY ROLES FOR INHERITED NONCODING VARIANTS IN THE PATHOGENESIS OF CLL. 2020 20 1518 34 DNA METHYLATION AS AN EPIGENETIC MECHANISM IN THE DEVELOPMENT OF MULTIPLE SCLEROSIS. THE EPIGENETIC MECHANISMS OF GENE EXPRESSION REGULATION ARE A GROUP OF THE KEY CELLULAR AND MOLECULAR PATHWAYS THAT LEAD TO INHERITED ALTERATIONS IN GENES' ACTIVITY WITHOUT CHANGING THEIR CODING SEQUENCE. DNA METHYLATION AT THE C5 POSITION OF CYTOSINE IN CPG DINUCLEOTIDES IS AMONGST THE CENTRAL EPIGENETIC MECHANISMS. CURRENTLY, THE NUMBER OF STUDIES THAT ARE DEVOTED TO THE IDENTIFICATION OF METHYLATION PATTERNS SPECIFIC TO MULTIPLE SCLEROSIS (MS), A SEVERE CHRONIC AUTOIMMUNE DISEASE OF THE CENTRAL NERVOUS SYSTEM, IS ON A RAPID RISE. HOWEVER, THE ISSUE OF THE CONTRIBUTION OF DNA METHYLATION TO THE DEVELOPMENT OF THE DIFFERENT CLINICAL PHENOTYPES OF THIS HIGHLY HETEROGENEOUS DISEASE HAS ONLY BEGUN TO ATTRACT THE ATTENTION OF RESEARCHERS. THIS REVIEW SUMMARIZES THE DATA ON THE MOLECULAR MECHANISMS UNDERLYING DNA METHYLATION AND THE MS RISK FACTORS THAT CAN AFFECT THE DNA METHYLATION PROFILE AND, THEREBY, MODULATE THE EXPRESSION OF THE GENES INVOLVED IN THE DISEASE'S PATHOGENESIS. THE FOCUS OF OUR ATTENTION IS CENTERED ON THE ANALYSIS OF THE PUBLISHED DATA ON THE DIFFERENTIAL METHYLATION OF DNA FROM VARIOUS BIOLOGICAL SAMPLES OF MS PATIENTS OBTAINED USING BOTH THE CANDIDATE GENE APPROACH AND HIGH-THROUGHPUT METHODS. 2021