1 3070 147 GENOME-WIDE DNA METHYLATION PROFILING IN CD8 T-CELLS AND GAMMA DELTA T-CELLS OF ASIAN INDIAN PATIENTS WITH TAKAYASU ARTERITIS. BACKGROUND: TAKAYASU'S ARTERITIS (TA) IS A CHRONIC INFLAMMATORY DISEASE THAT AFFECTS AORTA AND ITS MAIN BRANCHES AT THEIR ORIGIN. GENETIC, PATHOLOGICAL AND FUNCTIONAL STUDIES HAVE SHOWN THAT CD8 AND GAMMA DELTA (GAMMA/DELTA) T-LYMPHOCYTES ARE INVOLVED IN INFLAMMATORY PROCESSES IN AFFECTED REGIONS OF ARTERIES CAUSING VASCULAR DAMAGE. THE MOLECULAR FUNCTION OF THESE LYMPHOCYTES REMAINS UNCLEAR AND CURRENTLY NO EPIGENETIC STUDIES ARE AVAILABLE IN TA. WE PRIMARILY PERFORMED GENOME WIDE METHYLATION ANALYSIS IN CD8 T CELLS AND GAMMADELTA T CELLS OF PATIENTS WITH TA AND COMPARED WITH HEALTHY CONTROLS. METHODS: WE RECRUITED 12 SUBJECTS IN EACH GROUP NAMELY TA PATIENT AND HEALTHY CONTROLS. BLOOD SAMPLES WERE COLLECTED AFTER OBTAINING INFORMED WRITTEN CONSENT. CD8 T CELLS AND GAMMADELTA T CELLS WERE SEPARATED FROM WHOLE BLOOD. DNA EXTRACTED FROM THESE CELLS AND WERE SUBJECTED TO BISULFITE TREATMENT. FINALLY, BISULFITE TREATED DNA WAS LOADED IN INFINIUM METHYLATION EPIC ARRAY. BIOINFORMATICS ANALYSIS WAS USED TO IDENTIFY DIFFERENTIAL METHYLATION REGIONS WHICH WERE THEN MAPPED TO GENES. RESULTS: INTERLEUKIN (IL)-32 AND LYMPHOTOXIN-A WERE GENES SIGNIFICANTLY HYPOMETHYLATED IN CD8 T-CELLS. ANTI-INFLAMMATORY CYTOKINE GENES, IL-10, IL-1RN AND IL-27 WERE HYPOMETHYLATED IN GAMMADELTA T CELLS OF TA PATIENTS AS COMPARED TO HEALTHY CONTROLS. GENE ENRICHMENT ANALYSIS USING GENE ONTOLOGY (GO) DATABASE AND KYOTO ENCYCLOPAEDIA OF GENES AND GENOMES (KEGG) IDENTIFIED THAT GENES INVOLVED IN T-CELL RECEPTOR SIGNALLING PATHWAYS WERE HYPOMETHYLATED IN CD8 T-CELLS AND HYPERMETHYLATED IN GAMMADELTA T CELLS OF TA PATIENTS. CONCLUSION: CD8 T-CELLS MIGHT PLAY A MAJOR ROLE IN IMMUNOPATHOGENESIS OF INFLAMMATION IN TA, WHEREAS GAMMADELTA T CELLS MAY PLAY A REGULATORY ROLE.	2022	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
2 1500  51 DNA METHYLATION ANALYSIS OF CD4+ T CELLS IN PATIENTS WITH PSORIASIS. PSORIASIS IS A CHRONIC INFLAMMATORY SKIN DISEASE THAT IS CHARACTERIZED BY ABERRANT CROSS-TALK BETWEEN KERATINOCYTES AND IMMUNE CELLS SUCH AS CD4+ T CELLS, RESULTING IN KERATINOCYTE HYPERPROLIFERATION IN THE EPIDERMIS. DNA METHYLATION, ONE OF SEVERAL EPIGENETIC MECHANISMS, PLAYS AN IMPORTANT ROLE IN GENE EXPRESSION WITHOUT CHANGING THE DNA SEQUENCE. SEVERAL STUDIES HAVE SUGGESTED THE INVOLVEMENT OF EPIGENETIC REGULATION IN SKIN LESIONS FROM PATIENTS WITH PSORIASIS. IN THIS STUDY, WE INVESTIGATED THE GENOME-WIDE DNA METHYLATION STATUS OF CD4+ T CELLS IN PATIENTS WITH PSORIASIS COMPARED WITH HEALTHY SUBJECTS USING METHYLATED DNA IMMUNOPRECIPITATION SEQUENCING (MEDIP-SEQ). THE RESULTS OF MEDIP-SEQ SHOWED THAT THE GLOBAL METHYLATION VALUES OF CD4+ T CELLS ARE HIGHER IN PATIENTS WITH PSORIASIS THAN IN HEALTHY CONTROLS, PARTICULARLY IN THE PROMOTER REGIONS. AMONG THE MOST HYPERMETHYLATED GENES IN THE PROMOTER REGIONS, WE SELECTED THE GENES WHOSE EXPRESSION IS SIGNIFICANTLY REDUCED IN THE CD4+ T CELLS OF PSORIASIS PATIENTS. STUDIES USING THE METHYLATION INHIBITOR 5-AZACYTIDINE IN VITRO METHYLATION ASSAYS HAVE SHOWN THAT THE DIFFERENTIAL EXPRESSION LEVELS WERE ASSOCIATED WITH THE METHYLATION STATUS OF EACH GENE. BISULFITE SEQUENCING OF THE TRANSCRIPTION START REGION OF PHOSPHATIDIC ACID PHOSPHATASE TYPE 2 DOMAIN CONTAINING 3 (PPAPDC3), ONE OF THE SELECTED GENES, SHOWED HYPERMETHYLATION IN THE CD4+ T CELLS OF PSORIASIS PATIENTS. THESE RESULTS SUGGESTED THAT THE METHYLATION STATUS, WHICH IS IDENTIFIED BY MEDIP-SEQ OF THE GENES, WAS CORRELATED WITH THE MRNA EXPRESSION LEVEL OF THE GENES. COLLECTIVELY, THE DNA METHYLATION STATUS IN CD4+ T CELLS MIGHT BE ASSOCIATED WITH THE PATHOGENESIS OF PSORIASIS.	2014	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
3 1571  58 DNA METHYLATION PATTERNS IN CD8(+) T CELLS DISCERN PSORIASIS FROM PSORIATIC ARTHRITIS AND CORRELATE WITH CUTANEOUS DISEASE ACTIVITY. BACKGROUND: PSORIASIS IS A T CELL-MEDIATED CHRONIC AUTOIMMUNE/INFLAMMATORY DISEASE. WHILE SOME PATIENTS EXPERIENCE DISEASE LIMITED TO THE SKIN (SKIN PSORIASIS), OTHERS DEVELOP JOINT INVOLVEMENT (PSORIATIC ARTHRITIS; PSA). IN THE ABSENCE OF DISEASE- AND/OR OUTCOME-SPECIFIC BIOMARKERS, AND AS ARTHRITIS CAN PRECEDE SKIN MANIFESTATIONS, DIAGNOSTIC AND THERAPEUTIC DELAYS ARE COMMON AND CONTRIBUTE TO DISEASE BURDEN AND DAMAGE ACCRUAL. OBJECTIVE: ALTERED EPIGENETIC MARKS, INCLUDING DNA METHYLATION, CONTRIBUTE TO EFFECTOR T CELL PHENOTYPES AND ALTERED CYTOKINE EXPRESSION IN AUTOIMMUNE/INFLAMMATORY DISEASES. THIS PROJECT AIMED AT THE IDENTIFICATION OF DISEASE-/OUTCOME-SPECIFIC DNA METHYLATION SIGNATURES IN CD8(+) T CELLS FROM PATIENTS WITH PSORIASIS AND PSA AS COMPARED TO HEALTHY CONTROLS. METHOD: PERIPHERAL BLOOD CD8(+) T CELLS FROM NINE HEALTHY CONTROLS, 10 PSORIASIS, AND SEVEN PSA PATIENTS WERE COLLECTED TO ANALYZE DNA METHYLATION MARKS USING ILLUMINA HUMAN METHYLATION EPIC BEADCHIPS (>850,000 CPGS PER SAMPLE). BIOINFORMATIC ANALYSIS WAS PERFORMED USING R (MINFI, LIMMA, CHAMP, AND DMRCATE PACKAGES). RESULTS: DNA METHYLATION PROFILES IN CD8(+) T CELLS DIFFERENTIATE HEALTHY CONTROLS FROM PSORIASIS PATIENTS [397 DIFFERENTIALLY METHYLATED POSITIONS (DMPS); 9 DIFFERENTIALLY METHYLATED REGIONS (DMRS) WHEN >/=CPGS PER DMR WERE CONSIDERED; 2 DMRS FOR >/=10 CPGS]. FURTHERMORE, PATIENTS WITH SKIN PSORIASIS CAN BE DISCRIMINATED FROM PSA PATIENTS [1,861 DMPS, 20 DMRS (>/=5 CPGS PER REGION), 4 DMRS (>/=10 CPGS PER REGION)]. GENE ONTOLOGY (GO) ANALYSES CONSIDERING GENES WITH >/=1 DMP IN THEIR PROMOTER DELIVERED METHYLATION DEFECTS IN SKIN PSORIASIS AND PSA PRIMARILY AFFECTING THE BMP SIGNALING PATHWAY AND ENDOPEPTIDASE REGULATOR ACTIVITY, RESPECTIVELY. GO ANALYSIS OF GENES ASSOCIATED WITH DMRS BETWEEN SKIN PSORIASIS AND PSA DEMONSTRATED AN ENRICHMENT OF GABAERGIC NEURON AND CORTEX NEURON DEVELOPMENT PATHWAYS. TREATMENT WITH CYTOKINE BLOCKERS ASSOCIATED WITH DNA METHYLATION CHANGES [2,372 DMPS; 1,907 DMPS WITHIN PROMOTERS, 7 DMRS (>/=5 CPG PER REGIONS)] AFFECTING TRANSFORMING GROWTH FACTOR BETA RECEPTOR AND TRANSMEMBRANE RECEPTOR PROTEIN SERINE/THREONINE KINASE SIGNALING PATHWAYS. LASTLY, A METHYLATION SCORE INCLUDING TNF AND IL-17 PATHWAY ASSOCIATED DMPS INVERSE CORRELATES WITH SKIN DISEASE ACTIVITY SCORES (PASI). CONCLUSION: PATIENTS WITH SKIN PSORIASIS EXHIBIT DNA METHYLATION PATTERNS IN CD8(+) T CELLS THAT ALLOW DIFFERENTIATION FROM PSA PATIENTS AND HEALTHY INDIVIDUALS, AND REFLECT CLINICAL ACTIVITY OF SKIN DISEASE. THUS, DNA METHYLATION PROFILING PROMISES POTENTIAL AS DIAGNOSTIC AND PROGNOSTIC TOOL TO BE USED FOR MOLECULAR PATIENT STRATIFICATION TOWARD INDIVIDUALIZED TREATMENT.	2021	
                                                                          
4 2400  46 EPIGENETIC REPROGRAMMING OF IMMUNE CELLS IN WOMEN WITH PCOS IMPACT GENES CONTROLLING REPRODUCTIVE FUNCTION. CONTEXT: POLYCYSTIC OVARY SYNDROME (PCOS) IS A CHRONIC DISEASE AFFECTING REPRODUCTIVE FUNCTION AND WHOLE-BODY METABOLISM. ALTHOUGH THE ETIOLOGY IS UNCLEAR, EMERGING EVIDENCE INDICATES THAT THE EPIGENETICS MAY BE A CONTRIBUTING FACTOR. OBJECTIVE: TO DETERMINE THE ROLE OF GLOBAL AND GENOME-WIDE EPIGENETIC MODIFICATIONS IN SPECIFIC IMMUNE CELLS IN PCOS COMPARED WITH CONTROLS AND WHETHER THESE COULD BE RELATED TO CLINICAL FEATURES OF PCOS. DESIGN: CROSS-SECTIONAL STUDY. PARTICIPANTS: WOMEN WITH (N = 17) OR WITHOUT PCOS (N = 17). SETTING: RECRUITED FROM THE GENERAL COMMUNITY. MAIN OUTCOME MEASURES: ISOLATED PERIPHERAL BLOOD MONONUCLEAR CELLS WERE ANALYZED USING MULTICOLOR FLOW CYTOMETRY METHODS TO DETERMINE GLOBAL DNA METHYLATION LEVELS IN A CELL-SPECIFIC FASHION. TRANSCRIPTOMIC AND GENOME-WIDE DNA METHYLATION ANALYSES WERE PERFORMED ON T HELPER CELLS USING RNA SEQUENCING AND REDUCED REPRESENTATION BISULFITE SEQUENCING. RESULTS: WOMEN WITH PCOS HAD LOWER GLOBAL DNA METHYLATION IN MONOCYTES (P = 0.006) AND IN T HELPER (P = 0.004), T CYTOTOXIC (P = 0.004), AND B CELLS (P = 0.03). SPECIFIC GENOME-WIDE DNA METHYLATION ANALYSIS OF T HELPER CELLS FROM WOMEN WITH PCOS IDENTIFIED 5581 DIFFERENTIALLY METHYLATED CPG SITES. FUNCTIONAL GENE ONTOLOGY ENRICHMENT ANALYSIS SHOWED THAT GENES LOCATED AT THE PROXIMITY OF DIFFERENTIALLY METHYLATED CPG SITES BELONG TO PATHWAYS RELATED TO REPRODUCTIVE FUNCTION AND IMMUNE CELL FUNCTION. HOWEVER, THESE GENES WERE NOT ALTERED AT THE TRANSCRIPTOMIC LEVEL. CONCLUSIONS: IT WAS SHOWN THAT PCOS IS ASSOCIATED WITH GLOBAL AND GENE-SPECIFIC DNA METHYLATION REMODELING IN A CELL TYPE-SPECIFIC MANNER. FURTHER INVESTIGATION IS WARRANTED TO DETERMINE WHETHER EPIGENETIC REPROGRAMMING OF IMMUNE CELLS IS IMPORTANT IN DETERMINING THE DIFFERENT PHENOTYPES OF PCOS.	2019	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
5 5393  43 REDUCED CHROMATIN ACCESSIBILITY TO CD4 T CELL SUPER-ENHANCERS ENCOMPASSING SUSCEPTIBILITY LOCI OF RHEUMATOID ARTHRITIS. BACKGROUND: RHEUMATOID ARTHRITIS (RA) IS AN INFLAMMATORY DISEASE THAT MANIFESTS AS A PRECLINICAL STAGE OF SYSTEMIC AUTOIMMUNITY FOLLOWED BY CHRONIC PROGRESSIVE SYNOVITIS. DISEASE-ASSOCIATED GENETIC SNP VARIANTS PREDOMINANTLY MAP TO NON-CODING, REGULATORY REGIONS OF FUNCTIONAL IMPORTANCE IN CD4 T CELLS, IMPLICATING THESE CELLS AS KEY REGULATORS. A BETTER UNDERSTANDING OF THE EPIGENOME OF CD4 T CELLS HOLDS THE PROMISE OF PROVIDING INFORMATION ON THE INTERACTION BETWEEN GENETIC SUSCEPTIBILITY AND EXOGENOUS FACTORS. METHODS: WE MAPPED REGIONS OF CHROMATIN ACCESSIBILITY USING ATAC-SEQ IN PERIPHERAL CD4 T CELL SUBSETS OF PATIENTS WITH RA (N=18) AND COMPARED THEM TO T CELLS FROM PATIENTS WITH PSORIATIC ARTHRITIS (N=11) AND AGE-MATCHED HEALTHY CONTROLS (N=10). TRANSCRIPTS OF SELECTED GENES WERE QUANTIFIED USING QPCR. FINDINGS: RA-ASSOCIATED EPIGENETIC SIGNATURES WERE IDENTIFIED THAT IN PART OVERLAPPED BETWEEN CENTRAL AND EFFECTOR MEMORY CD4 T CELLS AND THAT WERE TO A LESSER EXTENT ALREADY PRESENT IN NAIVE CELLS. SITES MORE ACCESSIBLE IN RA WERE HIGHLY ENRICHED FOR THE MOTIF OF THE TRANSCRIPTION FACTOR (TF) CTCF SUGGESTING DIFFERENCES IN THE THREE-DIMENSIONAL CHROMATIN STRUCTURE. UNEXPECTEDLY, SITES WITH REDUCED CHROMATIN ACCESSIBILITY WERE ENRICHED FOR MOTIFS OF TFS PERTINENT FOR T CELL FUNCTION. MOST STRIKINGLY, SUPER-ENHANCERS ENCOMPASSING RA-ASSOCIATED SNPS WERE LESS ACCESSIBLE. ANALYSIS OF SELECTED TRANSCRIPTS AND PUBLISHED DNA METHYLATION PATTERNS WERE CONSISTENT WITH THIS FINDING. THE PREFERENTIAL LOSS IN ACCESSIBILITY AT THESE SUPER-ENHANCERS WAS SEEN IN PATIENTS WITH HIGH AND LOW DISEASE ACTIVITY AND ON A VARIETY OF IMMUNOSUPPRESSIVE TREATMENT MODALITIES. INTERPRETATION: DISEASE-ASSOCIATED GENES ARE EPIGENETICALLY LESS POISED TO RESPOND IN CD4 T CELLS FROM PATIENTS WITH ESTABLISHED RA. FUNDING: THIS WORK WAS SUPPORTED BY I01 BX001669 FROM THE VETERANS ADMINISTRATION.	2022	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
6 1570  56 DNA METHYLATION PATTERNS IN CD4(+) T-CELLS SEPARATE PSORIASIS PATIENTS FROM HEALTHY CONTROLS, AND SKIN PSORIASIS FROM PSORIATIC ARTHRITIS. BACKGROUND: PSORIASIS IS AN AUTOIMMUNE/INFLAMMATORY DISORDER PRIMARILY AFFECTING THE SKIN. CHRONIC JOINT INFLAMMATION TRIGGERS THE DIAGNOSIS OF PSORIATIC ARTHRITIS (PSA) IN APPROXIMATELY ONE-THIRD OF PSORIASIS PATIENTS. ALTHOUGH JOINT DISEASE TYPICALLY FOLLOWS THE ONSET OF SKIN PSORIASIS, IN AROUND 15% OF CASES IT IS THE INITIAL PRESENTATION, WHICH CAN RESULT IN DIAGNOSTIC DELAYS. THE PATHOPHYSIOLOGICAL MECHANISMS UNDERLYING PSORIASIS AND PSA ARE NOT YET FULLY UNDERSTOOD, BUT THERE IS EVIDENCE POINTING TOWARDS EPIGENETIC DYSREGULATION INVOLVING CD4(+) AND CD8(+) T-CELLS. OBJECTIVES: THE AIM OF THIS STUDY WAS TO INVESTIGATE DISEASE-ASSOCIATED DNA METHYLATION PATTERNS IN CD4(+) T-CELLS FROM PSORIASIS AND PSA PATIENTS THAT MAY REPRESENT POTENTIAL DIAGNOSTIC AND/OR PROGNOSTIC BIOMARKERS. METHODS: PBMCS WERE COLLECTED FROM 12 PATIENTS WITH CHRONIC PLAQUE PSORIASIS AND 8 PSA PATIENTS, AND 8 HEALTHY CONTROLS. CD4(+) T-CELLS WERE SEPARATED THROUGH FACS SORTING, AND DNA METHYLATION PROFILING WAS PERFORMED (ILLUMINA EPIC850K ARRAYS). BIOINFORMATIC ANALYSES, INCLUDING GENE ONTOLOGY (GO) AND KEGG PATHWAY ANALYSIS, WERE PERFORMED USING R. TO IDENTIFY GENES UNDER THE CONTROL OF INTERFERON (IFN), THE INTERFEROME DATABASE WAS CONSULTED, AND DNA METHYLATION SCORES WERE CALCULATED. RESULTS: NUMBERS AND PROPORTIONS OF CD4(+) T-CELL SUBSETS (NAIVE, CENTRAL MEMORY, EFFECTOR MEMORY, CD45RA RE-EXPRESSING EFFECTOR MEMORY CELLS) DID NOT VARY BETWEEN CONTROLS, SKIN PSORIASIS AND PSA PATIENTS. 883 DIFFERENTIALLY METHYLATED POSITIONS (DMPS) AFFECTING 548 GENES WERE IDENTIFIED BETWEEN CONTROLS AND "ALL" PSORIASIS PATIENTS. PRINCIPAL COMPONENT AND PARTIAL LEAST-SQUARES DISCRIMINANT ANALYSIS SEPARATED CONTROLS FROM SKIN PSORIASIS AND PSA PATIENTS. GO ANALYSIS CONSIDERING PROMOTER DMPS DELIVERED HYPERMETHYLATION OF GENES INVOLVED IN "REGULATION OF WOUND HEALING, SPREADING OF EPIDERMAL CELLS", "NEGATIVE REGULATION OF CELL-SUBSTRATE JUNCTION ORGANIZATION" AND "NEGATIVE REGULATION OF FOCAL ADHESION ASSEMBLY". COMPARING CONTROLS AND "ALL" PSORIASIS, A MAJORITY OF DMPS MAPPED TO IFN-RELATED GENES (69.2%). NOTABLY, DNA METHYLATION PROFILES ALSO DISTINGUISHED SKIN PSORIASIS FROM PSA PATIENTS (2,949 DMPS/1,084 GENES) THROUGH GENES AFFECTING "CAMP-DEPENDENT PROTEIN KINASE INHIBITOR ACTIVITY" AND "CAMP-DEPENDENT PROTEIN KINASE REGULATOR ACTIVITY". TREATMENT WITH CYTOKINE INHIBITORS (IL-17/TNF) CORRECTED DNA METHYLATION PATTERNS OF IL-17/TNF-ASSOCIATED GENES, AND METHYLATION SCORES CORRELATED WITH SKIN DISEASE ACTIVITY SCORES (PASI). CONCLUSION: DNA METHYLATION PROFILES IN CD4(+) T-CELLS DISCRIMINATE BETWEEN SKIN PSORIASIS AND PSA. DNA METHYLATION SIGNATURES MAY BE APPLIED FOR QUANTIFICATION OF DISEASE ACTIVITY AND PATIENT STRATIFICATION TOWARDS INDIVIDUALIZED TREATMENT.	2023	

7 2418  44 EPIGENETIC SIGNATURE OF CHRONIC LOW BACK PAIN IN HUMAN T CELLS. OBJECTIVE: DETERMINE IF CHRONIC LOW BACK PAIN (LBP) IS ASSOCIATED WITH DNA METHYLATION SIGNATURES IN HUMAN T CELLS THAT WILL REVEAL NOVEL MECHANISMS AND POTENTIAL THERAPEUTIC TARGETS AND EXPLORE THE FEASIBILITY OF EPIGENETIC DIAGNOSTIC MARKERS FOR PAIN-RELATED PATHOPHYSIOLOGY. METHODS: GENOME-WIDE DNA METHYLATION ANALYSIS OF 850,000 CPG SITES IN WOMEN AND MEN WITH CHRONIC LBP AND PAIN-FREE CONTROLS WAS PERFORMED. T CELLS WERE ISOLATED (DISCOVERY COHORT, N = 32) AND USED TO IDENTIFY DIFFERENTIALLY METHYLATED CPG SITES, AND GENE ONTOLOGIES AND MOLECULAR PATHWAYS WERE IDENTIFIED. A POLYGENIC DNA METHYLATION SCORE FOR LBP WAS GENERATED IN BOTH WOMEN AND MEN. VALIDATION WAS PERFORMED IN AN INDEPENDENT COHORT (VALIDATION COHORT, N = 63) OF CHRONIC LBP AND HEALTHY CONTROLS. RESULTS: ANALYSIS WITH THE DISCOVERY COHORT REVEALED A TOTAL OF 2,496 AND 419 DIFFERENTIALLY METHYLATED CPGS IN WOMEN AND MEN, RESPECTIVELY. IN WOMEN, MOST OF THESE SITES WERE HYPOMETHYLATED AND ENRICHED IN GENES WITH FUNCTIONS IN THE EXTRACELLULAR MATRIX, IN THE IMMUNE SYSTEM (IE, CYTOKINES), OR IN EPIGENETIC PROCESSES. IN MEN, A UNIQUE CHRONIC LBP DNA METHYLATION SIGNATURE WAS IDENTIFIED CHARACTERIZED BY SIGNIFICANT ENRICHMENT FOR GENES FROM THE MAJOR HISTOCOMPATIBILITY COMPLEX. SEX-SPECIFIC POLYGENIC DNA METHYLATION SCORES WERE GENERATED TO ESTIMATE THE PAIN STATUS OF EACH INDIVIDUAL AND CONFIRMED IN THE VALIDATION COHORT USING PYROSEQUENCING. CONCLUSION: THIS STUDY REVEALS SEX-SPECIFIC DNA METHYLATION SIGNATURES IN HUMAN T CELLS THAT DISCRIMINATES CHRONIC LBP PARTICIPANTS FROM HEALTHY CONTROLS.	2021	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
8 3069  48 GENOME-WIDE DNA METHYLATION PROFILING IDENTIFIES EPIGENETIC CHANGES IN CD4+ AND CD14+ CELLS OF MULTIPLE SCLEROSIS PATIENTS. MULTIPLE SCLEROSIS (MS) IS A CHRONIC AUTOIMMUNE AND DEGENERATIVE DISEASE OF THE CENTRAL NERVOUS SYSTEM, WHICH DEVELOPS IN GENETICALLY PREDISPOSED INDIVIDUALS UPON EXPOSURE TO ENVIRONMENTAL INFLUENCES. ENVIRONMENTAL TRIGGERS OF MS, SUCH AS VIRAL INFECTIONS OR SMOKING, WERE DEMONSTRATED TO AFFECT DNA METHYLATION, AND THUS TO INVOLVE THIS IMPORTANT EPIGENETIC MECHANISM IN THE DEVELOPMENT OF PATHOLOGICAL PROCESS. TO IDENTIFY MS-ASSOCIATED DNA METHYLATION HALLMARKS, WE PERFORMED GENOME-WIDE DNA METHYLATION PROFILING OF TWO CELL POPULATIONS (CD4+ T-LYMPHOCYTES AND CD14+ MONOCYTES), COLLECTED FROM THE SAME TREATMENT-NAIVE RELAPSING-REMITTING MS PATIENTS AND HEALTHY SUBJECTS, USING ILLUMINA 450 K METHYLATION ARRAYS. WE REVEALED SIGNIFICANT CHANGES IN DNA METHYLATION FOR BOTH CELL POPULATIONS IN MS. IN CD4+ CELLS OF MS PATIENTS THE MAJORITY OF DIFFERENTIALLY METHYLATED POSITIONS (DMPS) WERE SHOWN TO BE HYPOMETHYLATED, WHILE IN CD14+ CELLS - HYPERMETHYLATED. DIFFERENTIAL METHYLATION OF HLA-DRB1 GENE IN CD4+ AND CD14+ CELLS WAS ASSOCIATED WITH CARRIAGE OF DRB1*15 ALLELE INDEPENDENTLY FROM THE DISEASE STATUS. BESIDES, ABOUT 20% OF IDENTIFIED DMPS WERE SHARED BETWEEN TWO CELL POPULATIONS AND HAD THE SAME DIRECTION OF METHYLATION CHANGES; THEY MAY BE INVOLVED IN BASIC EPIGENETIC PROCESSES OCCURING IN MS. THESE FINDINGS SUGGEST THAT THE EPIGENETIC MECHANISM OF DNA METHYLATION IN IMMUNE CELLS CONTRIBUTES TO MS; FURTHER STUDIES ARE NOW REQUIRED TO VALIDATE THESE RESULTS AND UNDERSTAND THEIR FUNCTIONAL SIGNIFICANCE.	2022	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
9 6311  33 THE RELATION BETWEEN DNA METHYLATION PATTERNS AND SERUM CYTOKINE LEVELS IN COMMUNITY-DWELLING ADULTS: A PRELIMINARY STUDY. BACKGROUND: THE LEVELS OF CIRCULATING CYTOKINES FLUCTUATE WITH AGE, ACUTE ILLNESS, AND CHRONIC DISEASE, AND ARE PREDICTIVE OF MORTALITY; THIS IS ALSO TRUE FOR PATTERNS OF DNA (CPG) METHYLATION. GIVEN THAT IMMUNE CELLS ARE PARTICULARLY SENSITIVE TO CHANGES IN THE CONCENTRATION OF CYTOKINES IN THEIR MICROENVIRONMENT, WE HYPOTHESIZED THAT SERUM LEVELS OF TNF, IL-6, IL-8 AND IL-10 WOULD CORRELATE WITH GENOME-WIDE ALTERATIONS IN THE DNA METHYLATION LEVELS OF BLOOD LEUKOCYTES. TO TEST THIS, WE EVALUATED COMMUNITY-DWELLING ADULTS (N = 14; 48-78 YEARS OLD) RECRUITED TO A PILOT STUDY FOR THE CANADIAN LONGITUDINAL STUDY ON AGING (CLSA), EXAMINING DNA METHYLATION PATTERNS IN PERIPHERAL BLOOD MONONUCLEAR CELLS USING THE ILLUMINA HUMANMETHYLATION 450 K BEADCHIP. RESULTS: WE SHOW THAT, APART FROM AGE, SERUM IL-10 LEVELS EXHIBITED THE MOST SUBSTANTIAL ASSOCIATION TO DNA METHYLATION PATTERNS, FOLLOWED BY TNF, IL-6 AND IL-8. FURTHERMORE, WHILE THE LEVELS OF THESE CYTOKINES WERE HIGHER IN ELDERLY ADULTS, NO ASSOCIATIONS WITH EPIGENETIC ACCELERATED AGING, DERIVED USING THE EPIGENETIC CLOCK, WERE OBSERVED. CONCLUSIONS: AS A PRELIMINARY STUDY WITH A SMALL SAMPLE SIZE, THE CONCLUSIONS DRAWN FROM THIS WORK MUST BE VIEWED WITH CAUTION; HOWEVER, OUR OBSERVATIONS ARE ENCOURAGING AND CERTAINLY WARRANT MORE SUITABLY POWERED STUDIES OF THIS RELATIONSHIP.	2017	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
10    3  48 "EPIGENOME-WIDE METHYLATION PROFILE OF CHRONIC KIDNEY DISEASE-DERIVED ARTERIAL DNA UNCOVERS NOVEL PATHWAYS IN DISEASE-ASSOCIATED CARDIOVASCULAR PATHOLOGY.". CHRONIC KIDNEY DISEASE (CKD) RELATED CARDIOVASCULAR DISEASE (CVD) IS CHARACTERIZED BY VASCULAR REMODELLING WITH WELL-ESTABLISHED STRUCTURAL AND FUNCTIONAL CHANGES IN THE VASCULAR WALL SUCH AS ARTERIAL STIFFNESS, MATRIX DEPOSITION, AND CALCIFICATION. THESE PHENOTYPIC CHANGES RESEMBLE PATHOLOGY SEEN IN AGEING, AND ARE LIKELY TO BE MEDIATED BY SUSTAINED ALTERATIONS IN GENE EXPRESSION, WHICH MAY BE CAUSED BY EPIGENETIC CHANGES SUCH AS TISSUE-SPECIFIC DNA METHYLATION. WE AIMED TO INVESTIGATE TISSUE SPECIFIC CHANGES IN DNA METHYLATION THAT OCCUR IN CKD-RELATED CVD. GENOME-WIDE DNA METHYLATION CHANGES WERE EXAMINED IN BISULPHITE CONVERTED GENOMIC DNA ISOLATED FROM THE VASCULAR MEDIA OF CKD AND HEALTHY ARTERIES. METHYLATION-SPECIFIC PCR WAS USED TO VALIDATE THE ARRAY DATA, AND THE ASSOCIATION BETWEEN DNA METHYLATION AND GENE AND PROTEIN EXPRESSION WAS EXAMINED. THE DNA METHYLATION AGE WAS COMPARED TO THE CHRONOLOGICAL AGE IN BOTH CASES AND CONTROLS. THREE HUNDRED AND NINETEEN DIFFERENTIALLY METHYLATED REGIONS (DMR) WERE IDENTIFIED SPREAD ACROSS THE GENOME. PATHWAY ANALYSIS REVEALED THAT DMRS ASSOCIATED WITH GENES WERE INVOLVED IN EMBRYONIC AND VASCULAR DEVELOPMENT, AND SIGNALLING PATHWAYS SUCH AS TGFBETA AND FGF. EXPRESSION OF TOP DIFFERENTIALLY METHYLATED GENE HOXA5 SHOWED A SIGNIFICANT NEGATIVE CORRELATION WITH DNA METHYLATION. INTERESTINGLY, DNA METHYLATION AGE AND CHRONOLOGICAL AGE WERE HIGHLY CORRELATED, BUT THERE WAS NO EVIDENCE OF ACCELERATED AGE-RELATED DNA METHYLATION IN THE ARTERIES OF CKD PATIENTS. IN CONCLUSION, WE DEMONSTRATED THAT DIFFERENTIAL DNA METHYLATION IN THE ARTERIAL TISSUE OF CKD PATIENTS REPRESENTS A POTENTIAL MEDIATOR OF ARTERIAL PATHOLOGY AND MAY BE USED TO UNCOVER NOVEL PATHWAYS IN THE GENESIS OF CKD-ASSOCIATED COMPLICATIONS.	2021	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
11 1589  49 DNA METHYLATION PROFILING IN A CIGARETTE SMOKE-EXPOSED MOUSE MODEL OF AIRWAY INFLAMMATION. PURPOSE: DNA METHYLATION, A MAJOR EPIGENETIC MODIFICATION, HAS BEEN DOCUMENTED TO PLAY AN IMPORTANT ROLE IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). IN THIS STUDY, WE AIMED TO PROFILE THE DNA METHYLATION PATTERNS IN A MOUSE MODEL OF AIRWAY INFLAMMATION INDUCED BY CIGARETTE SMOKE (CS), A FOREMOST RISK FACTOR OF COPD. MATERIAL AND METHODS: TO ESTABLISH A MODEL OF AIRWAY INFLAMMATION, WILD-TYPE MICE WERE EXPOSED TO MAINSTREAM CS OR ROOM AIR FOR 2 HOURS TWICE DAILY, 6 DAYS PER WEEK FOR CONSECUTIVE 4 WEEKS. LUNG TISSUES OF THE MICE WERE COLLECTED FOR GENOME-WIDE DNA METHYLATION ANALYSIS BY LIQUID HYBRIDIZATION CAPTURE-BASED BISULFITE SEQUENCING, WHICH WERE USED FOR INTERSECTION ANALYSIS WITH GENE EXPRESSION BY CDNA MICROARRAY TO IDENTIFY CANDIDATE METHYLATED GENES. THEN, FUNCTIONAL ENRICHMENT ANALYSES WITH PROTEIN-PROTEIN INTERACTION (PPI) NETWORK REGARDING THESE GENES WERE CONDUCTED TO EXPLORE THE POTENTIAL MECHANISMS. RESULTS: AFTER 4-WEEK CS EXPOSURE, THE LEVEL OF DNA METHYLATION ACCOMPANIED BY A SUBACUTE AIRWAY INFLAMMATION WAS MARKEDLY ENHANCED, AND 2002 DIFFERENTIALLY METHYLATED GENES (DMGS) WERE ANNOTATED, INCLUDING 565 DMGS CONTAINED METHYLATIONS IN GENE PROMOTERS, WHICH WERE USED FOR INTERSECTION WITH THE DIFFERENTIALLY EXPRESSED GENES. THEN, 135 CANDIDATE METHYLATED GENES WERE FURTHER SELECTED BY THE INTERSECTION, AMONG WHICH 58 GENES WITH FUNCTIONAL METHYLATED MODIFICATION WERE FINALLY IDENTIFIED. FURTHER ANALYSES REVEALED CANDIDATE METHYLATED GENES WERE SIGNIFICANTLY ENRICHED IN A COMPLICATED NETWORK OF SIGNALS AND PROCESSES, INCLUDING INTERLEUKINS, TOLL-LIKE RECEPTORS, T-CELLS DIFFERENTIATION, OXIDATIVE STRESS, MAST CELLS ACTIVATION, STEM CELLS PROLIFERATION, ETC., AS WELL AS THE 58 FUNCTIONAL METHYLATED GENES WERE PARTIALLY LOCATED AT KEY POSITIONS IN PPI NETWORK, ESPECIALLY CXCL1, DDX58 AND JAK3. CONCLUSION: THIS STUDY SUGGESTS CS EXPOSURE SIGNIFICANTLY ENHANCES DNA METHYLATED LEVEL, AND THE POTENTIAL FUNCTIONAL METHYLATED GENES ARE CLOSELY RELATED TO COMPLICATED INFLAMMATORY-IMMUNE RESPONSES, WHICH MAY PROVIDE SOME NEW EXPERIMENTAL EVIDENCE IN UNDERSTANDING THE EPIGENETIC MECHANISMS OF CS-INDUCED AIRWAY INFLAMMATION IN COPD.	2022	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
12 2771  32 EXTENSIVE PROMOTER DNA HYPERMETHYLATION AND HYPOMETHYLATION IS ASSOCIATED WITH ABERRANT MICRORNA EXPRESSION IN CHRONIC LYMPHOCYTIC LEUKEMIA. DYSREGULATED MICRORNA (MIRNA) EXPRESSION CONTRIBUTES TO THE PATHOGENESIS OF HEMATOPOIETIC MALIGNANCIES, INCLUDING CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). HOWEVER, AN UNDERSTANDING OF THE MECHANISMS THAT CAUSE ABERRANT MIRNA TRANSCRIPTIONAL CONTROL IS LACKING. IN THIS STUDY, WE COMPREHENSIVELY INVESTIGATED THE ROLE AND EXTENT OF MIRNA EPIGENETIC REGULATION IN CLL. GENOME-WIDE PROFILING CONDUCTED ON 24 CLL AND 10 HEALTHY B CELL SAMPLES REVEALED GLOBAL DNA METHYLATION PATTERNS UPSTREAM OF MIRNA SEQUENCES THAT DISTINGUISHED MALIGNANT FROM HEALTHY CELLS AND IDENTIFIED PUTATIVE MIRNA PROMOTERS. INTEGRATION OF DNA METHYLATION AND MIRNA PROMOTER DATA LED TO THE IDENTIFICATION OF 128 RECURRENT MIRNA TARGETS FOR ABERRANT PROMOTER DNA METHYLATION. DNA HYPOMETHYLATION ACCOUNTED FOR MORE THAN 60% OF ALL ABERRANT PROMOTER-ASSOCIATED DNA METHYLATION IN CLL, AND PROMOTER DNA HYPOMETHYLATION WAS RESTRICTED TO WELL-DEFINED REGIONS. INDIVIDUAL HYPER- AND HYPOMETHYLATED PROMOTERS ALLOWED DISCRIMINATION OF CLL SAMPLES FROM HEALTHY CONTROLS. PROMOTER DNA METHYLATION PATTERNS WERE CONFIRMED IN AN INDEPENDENT PATIENT COHORT, WITH 11 MIRNAS CONSISTENTLY SHOWING AN INVERSE CORRELATION BETWEEN DNA METHYLATION STATUS AND EXPRESSION LEVEL. TOGETHER, OUR FINDINGS CHARACTERIZE THE ROLE OF EPIGENETIC CHANGES IN THE REGULATION OF MIRNA TRANSCRIPTION AND CREATE A REPOSITORY OF DISEASE-SPECIFIC PROMOTER REGIONS THAT MAY PROVIDE ADDITIONAL INSIGHTS INTO THE PATHOGENESIS OF CLL.	2012	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
13 3079  56 GENOME-WIDE METHYLATION AND EXPRESSION ANALYSES REVEAL THE EPIGENETIC LANDSCAPE OF IMMUNE-RELATED DISEASES FOR TOBACCO SMOKING. BACKGROUND: SMOKING IS A MAJOR CAUSAL RISK FACTOR FOR LUNG CANCER, CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD), CARDIOVASCULAR DISEASE (CVD), AND IS THE MAIN PREVENTABLE CAUSE OF DEATHS IN THE WORLD. THE COMPONENTS OF CIGARETTE SMOKE ARE INVOLVED IN IMMUNE AND INFLAMMATORY PROCESSES, WHICH MAY INCREASE THE PREVALENCE OF CIGARETTE SMOKE-RELATED DISEASES. HOWEVER, THE UNDERLYING MOLECULAR MECHANISMS LINKING SMOKING AND DISEASES HAVE NOT BEEN WELL EXPLORED. THIS STUDY WAS AIMED TO DEPICT A GLOBAL MAP OF DNA METHYLATION AND GENE EXPRESSION CHANGES INDUCED BY TOBACCO SMOKING AND TO EXPLORE THE MOLECULAR MECHANISMS BETWEEN SMOKING AND HUMAN DISEASES THROUGH WHOLE-GENOME BISULFITE SEQUENCING (WGBS) AND RNA-SEQUENCING (RNA-SEQ). RESULTS: WE PERFORMED WGBS ON 72 SAMPLES (36 SMOKERS AND 36 NONSMOKERS) AND RNA-SEQ ON 75 SAMPLES (38 SMOKERS AND 37 NONSMOKERS), AND CYTOKINE IMMUNOASSAY ON PLASMA FROM 22 MALES (9 SMOKERS AND 13 NONSMOKERS) WHO WERE RECRUITED FROM THE CITY OF JINCHENG IN CHINA. BY COMPARING THE DATA OF THE TWO GROUPS, WE DISCOVERED A GENOME-WIDE METHYLATION LANDSCAPE OF DIFFERENTIALLY METHYLATED REGIONS (DMRS) ASSOCIATED WITH SMOKING. FUNCTIONAL ENRICHMENT ANALYSES REVEALED THAT BOTH SMOKING-RELATED HYPER-DMR GENES (DMGS) AND HYPO-DMGS WERE RELATED TO SYNAPSE-RELATED PATHWAYS, WHEREAS THE HYPO-DMGS WERE SPECIFICALLY RELATED TO CANCER AND ADDICTION. THE DIFFERENTIALLY EXPRESSED GENES (DEGS) REVEALED BY RNA-SEQ ANALYSIS WERE SIGNIFICANTLY ENRICHED IN THE "IMMUNOSUPPRESSION" PATHWAY. CORRELATION ANALYSIS OF DMRS WITH THEIR CORRESPONDING GENE EXPRESSION SHOWED THAT GENES AFFECTED BY TOBACCO SMOKING WERE MOSTLY RELATED TO IMMUNE SYSTEM DISEASES. FINALLY, BY COMPARING CYTOKINE CONCENTRATIONS BETWEEN SMOKERS AND NONSMOKERS, WE FOUND THAT VASCULAR ENDOTHELIAL GROWTH FACTOR (VEGF) WAS SIGNIFICANTLY UPREGULATED IN SMOKERS. CONCLUSIONS: IN SUM, WE FOUND THAT SMOKING-INDUCED DMRS HAVE DIFFERENT DISTRIBUTION PATTERNS IN HYPERMETHYLATED AND HYPOMETHYLATED AREAS BETWEEN SMOKERS AND NONSMOKERS. WE FURTHER IDENTIFIED AND VERIFIED SMOKING-RELATED DMGS AND DEGS THROUGH MULTI-OMICS INTEGRATION ANALYSIS OF DNA METHYLOME AND TRANSCRIPTOME DATA. THESE FINDINGS PROVIDE US A COMPREHENSIVE GENOMIC MAP OF THE MOLECULAR CHANGES INDUCED BY SMOKING WHICH WOULD ENHANCE OUR UNDERSTANDING OF THE HARMS OF SMOKING AND ITS RELATIONSHIP WITH DISEASES.	2021	
                                                                                                                                                                                                                                                                                                                                                                                                                                             
14 2766  36 EXPRESSION, POLYMORPHISM AND METHYLATION PATTERN OF INTERLEUKIN-6 IN PERIODONTAL TISSUES. PERIODONTITIS IS CONSIDERED AN INFLAMMATORY DISORDER OF BACTERIAL ETIOLOGY THAT RESULTS IN PERIODONTAL TISSUE DESTRUCTION, AS A RESULT OF COMPLEX INTERACTIONS BETWEEN PERIODONTAL PATHOGENS, HOST AND IMMUNE RESPONSE. GENETIC AND EPIGENETIC MECHANISMS MAY MODULATE THE INDIVIDUAL RESPONSE SINCE IT IS ABLE TO INFLUENCE THE GENE EXPRESSION. THE AIM OF THIS STUDY WAS TO EVALUATE THE IMPACT OF -174 G/C POLYMORPHISM AND THE METHYLATION STATUS OF THE PROMOTER REGION OF IL-6 GENE ON THE EXPRESSION OF IL-6 IN GINGIVAL SAMPLES FROM INDIVIDUALS WITH CHRONIC PERIODONTITIS. GINGIVAL BIOPSIES WERE COLLECTED FROM 21 PATIENTS WITH CHRONIC PERIODONTITIS AND 21 CONTROLS. HISTOLOGIC SECTIONS STAINED BY HEMATOXYLIN-EOSIN WERE USED FOR HISTOPATHOLOGICAL EVALUATION. THE IL-6 GENE EXPRESSION WAS ASSESSED BY QUANTITATIVE REAL-TIME PCR. THE POLYMORPHISM IL-6 -174 C/G WAS STUDIED BY POLYMERASE CHAIN REACTION (PCR) AMPLIFICATION AND RESTRICTION ENDONUCLEASE DIGESTION (HSPII). METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION WAS USED TO VERIFY THE DNA METHYLATION PATTERN. THE NUMBER OF INFLAMMATORY CELLS IN TISSUE FRAGMENTS FROM INDIVIDUALS WITH CHRONIC PERIODONTITIS WAS HIGHER THAN IN THE CONTROL GROUP AND THE INFLAMMATORY INFILTRATE WAS PREDOMINANTLY MONONUCLEAR. THE EXPRESSION OF IL-6 WAS HIGHER IN THE GROUP WITH PERIODONTITIS. IN POLYMORPHISM ASSAY, NO STATISTICAL DIFFERENCE IN THE DISTRIBUTION OF GENOTYPES AND ALLELES IN BOTH GROUPS WERE OBSERVED. THE MOST OF SAMPLES WERE PARTIALLY METHYLATED. NO DIFFERENCE WAS OBSERVED IN METHYLATION PATTERN FROM TWO DIFFERENT REGIONS OF THE IL-6 GENE AMONG GROUPS. THE HIGH EXPRESSION OF IL-6 IS AN IMPORTANT FACTOR RELATED TO CHRONIC PERIODONTITIS, BUT WAS NOT ASSOCIATED WITH METHYLATION STATUS OR THE -174 (G/C) GENETIC POLYMORPHISM, SUGGESTING THAT OTHER MECHANISMS ARE INVOLVED IN THIS GENE TRANSCRIPTION REGULATION.	2013	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
15 3422  36 HUMAN MONOCYTE-TO-MACROPHAGE DIFFERENTIATION INVOLVES HIGHLY LOCALIZED GAIN AND LOSS OF DNA METHYLATION AT TRANSCRIPTION FACTOR BINDING SITES. BACKGROUND: MACROPHAGES AND THEIR PRECURSORS MONOCYTES PLAY A KEY ROLE IN INFLAMMATION AND CHRONIC INFLAMMATORY DISORDERS. MONOCYTE-TO-MACROPHAGE DIFFERENTIATION AND ACTIVATION PROGRAMS ARE ACCOMPANIED BY SIGNIFICANT EPIGENETIC REMODELING WHERE DNA METHYLATION ASSOCIATES WITH CELL IDENTITY. HERE WE SHOW THAT DNA METHYLATION CHANGES CHARACTERISTIC FOR MONOCYTE-TO-MACROPHAGE DIFFERENTIATION OCCUR AT TRANSCRIPTION FACTOR BINDING SITES, AND, IN CONTRAST TO WHAT WAS PREVIOUSLY DESCRIBED, ARE GENERALLY HIGHLY LOCALIZED AND ENCOMPASS BOTH LOSSES AND GAINS OF DNA METHYLATION. RESULTS: WE COMPARED GENOME-WIDE DNA METHYLATION ACROSS 440,292 CPG SITES BETWEEN HUMAN MONOCYTES, NAIVE MACROPHAGES AND MACROPHAGES FURTHER ACTIVATED TOWARD A PRO-INFLAMMATORY STATE (USING LPS/IFNGAMMA), AN ANTI-INFLAMMATORY STATE (IL-4) OR FOAM CELLS (OXLDL AND ACLDL). MOREOVER, WE INTEGRATED THESE DATA WITH PUBLIC WHOLE-GENOME SEQUENCING DATA ON MONOCYTES AND MACROPHAGES TO DEMARCATE DIFFERENTIALLY METHYLATED REGIONS. OUR ANALYSIS SHOWED THAT DIFFERENTIAL DNA METHYLATION WAS MOST PRONOUNCED DURING MONOCYTE-TO-MACROPHAGE DIFFERENTIATION, WAS TYPICALLY RESTRICTED TO SINGLE CPGS OR VERY SHORT REGIONS, AND CO-LOCALIZED WITH LINEAGE-SPECIFIC ENHANCERS IRRESPECTIVE OF WHETHER IT CONCERNS GAIN OR LOSS OF METHYLATION. FURTHERMORE, DIFFERENTIALLY METHYLATED CPGS WERE LOCATED AT SITES CHARACTERIZED BY INCREASED BINDING OF TRANSCRIPTION FACTORS KNOWN TO BE INVOLVED IN MONOCYTE-TO-MACROPHAGE DIFFERENTIATION INCLUDING C/EBP AND ETS FOR GAIN AND AP-1 FOR LOSS OF METHYLATION. CONCLUSION: OUR STUDY HIGHLIGHTS THE INVOLVEMENT OF SUBTLE, YET HIGHLY LOCALIZED REMODELING OF DNA METHYLATION AT REGULATORY REGIONS IN CELL DIFFERENTIATION.	2019	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
16 2920  44 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	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
17 2633  46 EPIGENOME-WIDE DNA METHYLATION PATTERNS ASSOCIATED WITH FATIGUE IN PRIMARY SJOGREN'S SYNDROME. OBJECTIVE: CHRONIC FATIGUE IS A COMMON, DISABLING AND POORLY UNDERSTOOD PHENOMENON. RECENT STUDIES INDICATE THAT EPIGENETIC MECHANISMS MAY BE INVOLVED IN THE EXPRESSION OF FATIGUE, A PROMINENT FEATURE OF PRIMARY SS (PSS). THE AIM OF THIS STUDY WAS TO INVESTIGATE WHETHER DNA METHYLATION PROFILES OF WHOLE BLOOD ARE ASSOCIATED WITH FATIGUE IN PATIENTS WITH PSS. METHODS: FORTY-EIGHT PSS PATIENTS WITH HIGH (N = 24) OR LOW (N = 24) FATIGUE AS MEASURED BY A VISUAL ANALOGUE SCALE WERE INCLUDED. GENOME-WIDE DNA METHYLATION WAS INVESTIGATED USING THE ILLUMINA HUMANMETHYLATION450 BEADCHIP ARRAY. AFTER QUALITY CONTROL, A TOTAL OF 383 358 CYTOSINE-PHOSPHATE-GUANINE (CPG) SITES REMAINED FOR FURTHER ANALYSIS. AGE, SEX AND DIFFERENTIAL CELL COUNT ESTIMATES WERE INCLUDED AS COVARIATES IN THE ASSOCIATION MODEL. A FALSE DISCOVERY RATE-CORRECTED P < 0.05 WAS CONSIDERED SIGNIFICANT, AND A CUT-OFF OF 3% AVERAGE DIFFERENCE IN METHYLATION LEVELS BETWEEN HIGH- AND LOW-FATIGUE PATIENTS WAS APPLIED. RESULTS: A TOTAL OF 251 DIFFERENTIALLY METHYLATED CPG SITES WERE ASSOCIATED WITH FATIGUE. THE CPG SITE WITH THE MOST PRONOUNCED HYPOMETHYLATION IN PSS HIGH FATIGUE ANNOTATED TO THE SBF2-ANTISENSE RNA1 GENE. THE MOST DISTINCT HYPERMETHYLATION WAS OBSERVED AT A CPG SITE ANNOTATED TO THE LYMPHOTOXIN ALPHA GENE. FUNCTIONAL PATHWAY ANALYSIS OF GENES WITH DIFFERENTLY METHYLATED CPG SITES IN SUBJECTS WITH HIGH VS LOW FATIGUE REVEALED ENRICHMENT IN SEVERAL PATHWAYS ASSOCIATED WITH INNATE AND ADAPTIVE IMMUNITY. CONCLUSION: SOME GENES INVOLVED IN REGULATION OF THE IMMUNE SYSTEM AND IN INFLAMMATION ARE DIFFERENTLY METHYLATED IN PSS PATIENTS WITH HIGH VS LOW FATIGUE. THESE FINDINGS POINT TO FUNCTIONAL NETWORKS THAT MAY UNDERLIE FATIGUE. EPIGENETIC CHANGES COULD CONSTITUTE A FATIGUE-REGULATING MECHANISM IN PSS.	2016	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
18 3068  34 GENOME-WIDE DNA METHYLATION PROFILING IDENTIFIES DIFFERENTIAL METHYLATION IN UNINVOLVED PSORIATIC EPIDERMIS. PSORIASIS IS A CHRONIC INFLAMMATORY SKIN DISEASE WITH BOTH LOCAL AND SYSTEMIC COMPONENTS. GENOME-WIDE APPROACHES HAVE IDENTIFIED MORE THAN 60 PSORIASIS-SUSCEPTIBILITY LOCI, BUT GENES ARE ESTIMATED TO EXPLAIN ONLY ONE-THIRD OF THE HERITABILITY IN PSORIASIS, SUGGESTING ADDITIONAL, YET UNIDENTIFIED, SOURCES OF HERITABILITY. EPIGENETIC MODIFICATIONS HAVE BEEN LINKED TO PSORIASIS AND ALTERED DNA METHYLATION PATTERNS IN PSORIATIC VERSUS HEALTHY SKIN HAVE BEEN REPORTED IN WHOLE-SKIN BIOPSIES. IN THIS STUDY, FOCUSING ON EPIGENETIC MODIFICATIONS IN THE PSORIATIC UNINVOLVED SKIN, WE COMPARED THE LESIONAL AND NON-LESIONAL EPIDERMIS FROM PSORIASIS PATIENTS WITH EPIDERMIS FROM HEALTHY CONTROLS. WE PERFORMED AN EXHAUSTIVE GENOME-WIDE DNA METHYLATION PROFILING USING REDUCED REPRESENTATION BISULFITE SEQUENCING, WHICH INTERROGATES THE METHYLATION STATUS OF APPROXIMATELY 3-4 MILLION CPG SITES. MORE THAN 2,000 STRONGLY DIFFERENTIALLY METHYLATED SITES WERE IDENTIFIED AND A STRIKING OVERREPRESENTATION OF THE WNT AND CADHERIN PATHWAYS AMONG THE DIFFERENTIALLY METHYLATED SITES WAS FOUND. IN PARTICULAR, WE OBSERVE A STRONG DIFFERENTIAL METHYLATION IN SEVERAL PSORIASIS CANDIDATE GENES. A SUBSTANTIAL NUMBER OF DIFFERENTIALLY METHYLATED SITES PRESENT IN THE UNINVOLVED VERSUS HEALTHY EPIDERMIS SUGGESTS THE PRESENCE OF A PRE-PSORIATIC STATE IN THE CLINICALLY HEALTHY SKIN TYPE. OUR EXPLORATORY STUDY REPRESENTS A STARTING POINT FOR IDENTIFYING BIOMARKERS FOR PSORIASIS-PRONE SKIN BEFORE DISEASE ONSET.	2018	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
19 3440  31 HYPERMETHYLATION AND LOW TRANSCRIPTION OF TLR2 GENE IN CHRONIC PERIODONTITIS. PERIODONTITIS IS AN INFLAMMATORY DISORDER CHARACTERIZED BY INTERACTIONS BETWEEN PERIODONTAL PATHOGENS AND HOST'S IMMUNE RESPONSE. EPIGENETIC MAY CONTRIBUTE TO DISEASE DEVELOPMENT AND OUTCOME BY INFLUENCING THE EXPRESSION OF GENES INVOLVED IN THE IMMUNE RESPONSE. IT HAS BEEN SHOWN THAT TOLL-LIKE RECEPTORS (TLR) PLAY AN IMPORTANT ROLE IN THE RESPONSE TO PERIODONTOPATHIC BACTERIA. THE AIM OF STUDY WAS TO EVALUATE THE METHYLATION STATUS AND THE EXPRESSION OF TLR2 GENE IN GINGIVAL SAMPLES FROM INDIVIDUALS WITH AND WITHOUT PERIODONTITIS. DNA WAS ANALYZED USING THE METHYL PROFILER DNA METHYLATION QPCR ASSAY. DNA METHYLATION AND TRANSCRIPT LEVELS WERE EVALUATED BY REAL-TIME POLYMERASE CHAIN REACTION. THE PERIODONTITIS GROUP SHOWED A HYPERMETHYLATED PROFILE AND A LOW EXPRESSION OF GENE. POSITIVE CORRELATION BETWEEN THE TLR2 METHYLATION FREQUENCY AND PROBING DEPTH WAS OBSERVED. THIS STUDY GIVES THE FIRST EVIDENCE OF METHYLATION FREQUENCY IN INFLAMED PERIODONTAL TISSUES AND OF THE POSSIBLE PARTICIPATION OF METHYLATION IN THE DEVELOPMENT OF PERIODONTITIS.	2013	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
20 3588  48 IMPACT OF TP53 GENE PROMOTER METHYLATION ON CHRONIC LYMPHOCYTIC LEUKEMIA PATHOGENESIS AND PROGRESSION. BACKGROUND: CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS A MALIGNANT LYMPHOID DISORDER THAT RESULTS FROM THE OVERGROWTH OF MATURE-LOOKING LYMPHOID CELLS IN THE BLOOD AND LYMPHATIC TISSUE. VARIOUS CLINICAL PRESENTATIONS HAVE BEEN ATTRIBUTED TO THE DISEASE AS A RESULT OF THE DIFFERENT UNDERLYING GENETIC AND EPIGENETIC ALTERATIONS. THE CURRENT STUDY HAS BEEN INITIATED TO STUDY THE ROLE OF AN EPIGENETIC ALTERATION AFFECTING THE PROMOTER OF THE TP53GENE ON CLL PATHOGENESIS AND PROGRESSION. METHODS: THE CURRENT STUDY INVOLVED 54 NEWLY DIAGNOSED PATIENTS PRESENTING WITH CLL AS WELL AS 30 NORMAL INDIVIDUALS AS CONTROLS. AFTER OBTAINING VERBAL CONSENT, DATA COLLECTION WAS DONE AND THE BLOOD COLLECTED FROM ALL ENROLLED INDIVIDUALS FOR HEMATOLOGICAL INVESTIGATIONS AS WELL AS FOR MOLECULAR CATEGORIZATION OF TP53 METHYLATION STATUS. METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION (MS-PCR) TECHNIQUE WAS USED TO DEFINE THE METHYLATION STATUS OF THE TP53 GENE PROMOTER THAT ENCOMPASSES DNA EXTRACTION, BISULFITE CONVERSION, CONVENTIONAL PCR AMPLIFICATION, RUNNING ON AGAROSE GEL AND DOCUMENTATION. FINALLY, STATISTICAL ANALYSIS WAS DONE TO ASSESS ANY CORRELATION OF THE TP53 EPIGENETIC ALTERATION TO THE DISEASE ETIOLOGY AND THE PROGRESSION. RESULTS: IN THE CURRENT STUDY, ALL CONTROLS AND 42 OF 54 PATIENTS SHOW UNMETHYLATED TP53 GENE PROMOTER; ON THE OTHER HAND, THE METHYLATED PROMOTER WAS DETECTED AMONG 12 PATIENTS WITH A P-VALUE OF 0.001. TP53 GENE PROMOTER METHYLATION SIGNIFICANTLY LINKED TO REDUCED PLATELET COUNT (P-VALUE OF 0.047) AND ADVANCED STAGE AT PRESENTATION (P-VALUE OF 0.076). NO SIGNIFICANT DIFFERENCES WERE SEEN AMONG BOTH METHYLATED AND UNMETHYLATED TP53 PROMOTERS IN RELATION TO THE AGE OF THE AFFECTED INDIVIDUALS, TOTAL WHITE BLOOD CELL COUNTS AND HEMOGLOBIN LEVEL OF THE AFFECTED INDIVIDUALS. CONCLUSION: THE CURRENT STUDY REVEALED A SIGNIFICANT CORRELATION OF TP53 GENE PROMOTER METHYLATION TO CHRONIC LYMPHOCYTIC LEUKEMIA PATHOGENESIS AND LOWER PLATELET COUNTS.	2019