1 3487 165 IDENTIFICATION OF DIFFERENTIALLY METHYLATED SITES WITH WEAK METHYLATION EFFECTS. DEOXYRIBONUCLEIC ACID (DNA) METHYLATION IS AN EPIGENETIC ALTERATION CRUCIAL FOR REGULATING STRESS RESPONSES. IDENTIFYING LARGE-SCALE DNA METHYLATION AT SINGLE NUCLEOTIDE RESOLUTION IS MADE POSSIBLE BY WHOLE GENOME BISULFITE SEQUENCING. AN ESSENTIAL TASK FOLLOWING THE GENERATION OF BISULFITE SEQUENCING DATA IS TO DETECT DIFFERENTIALLY METHYLATED CYTOSINES (DMCS) AMONG TREATMENTS. MOST STATISTICAL METHODS FOR DMC DETECTION DO NOT CONSIDER THE DEPENDENCY OF METHYLATION PATTERNS ACROSS THE GENOME, THUS POSSIBLY INFLATING TYPE I ERROR. FURTHERMORE, SMALL SAMPLE SIZES AND WEAK METHYLATION EFFECTS AMONG DIFFERENT PHENOTYPE CATEGORIES MAKE IT DIFFICULT FOR THESE STATISTICAL METHODS TO ACCURATELY DETECT DMCS. TO ADDRESS THESE ISSUES, THE WAVELET-BASED FUNCTIONAL MIXED MODEL (WFMM) WAS INTRODUCED TO DETECT DMCS. TO FURTHER EXAMINE THE PERFORMANCE OF WFMM IN DETECTING WEAK DIFFERENTIAL METHYLATION EVENTS, WE USED BOTH SIMULATED AND EMPIRICAL DATA AND COMPARE WFMM PERFORMANCE TO A POPULAR DMC DETECTION TOOL METHYLKIT. ANALYSES OF SIMULATED DATA THAT REPLICATED THE EFFECTS OF THE HERBICIDE GLYPHOSATE ON DNA METHYLATION IN ARABIDOPSIS THALIANA SHOW THAT WFMM RESULTS IN HIGHER SENSITIVITY AND SPECIFICITY IN DETECTING DMCS COMPARED TO METHYLKIT, ESPECIALLY WHEN THE METHYLATION DIFFERENCES AMONG PHENOTYPE GROUPS ARE SMALL. MOREOVER, THE PERFORMANCE OF WFMM IS ROBUST WITH RESPECT TO SMALL SAMPLE SIZES, MAKING IT PARTICULARLY ATTRACTIVE CONSIDERING THE CURRENT HIGH COSTS OF BISULFITE SEQUENCING. ANALYSIS OF EMPIRICAL ARABIDOPSIS THALIANA DATA UNDER VARYING GLYPHOSATE DOSAGES, AND THE ANALYSIS OF MONOZYGOTIC (MZ) TWINS WHO HAVE DIFFERENT PAIN SENSITIVITIES-BOTH DATASETS HAVE WEAK METHYLATION EFFECTS OF <1%-SHOW THAT WFMM CAN IDENTIFY MORE RELEVANT DMCS RELATED TO THE PHENOTYPE OF INTEREST THAN METHYLKIT. DIFFERENTIALLY METHYLATED REGIONS (DMRS) ARE GENOMIC REGIONS WITH DIFFERENT DNA METHYLATION STATUS ACROSS BIOLOGICAL SAMPLES. DMRS AND DMCS ARE ESSENTIALLY THE SAME CONCEPTS, WITH THE ONLY DIFFERENCE BEING HOW METHYLATION INFORMATION ACROSS THE GENOME IS SUMMARIZED. IF METHYLATION LEVELS ARE DETERMINED BY GROUPING NEIGHBORING CYTOSINE SITES, THEN THEY ARE DMRS; IF METHYLATION LEVELS ARE CALCULATED BASED ON SINGLE CYTOSINES, THEY ARE DMCS. 2018 2 1345 49 DETECTION OF DIFFERENTIALLY METHYLATED REGIONS USING BAYES FACTOR FOR ORDINAL GROUP RESPONSES. RESEARCHERS IN GENOMICS ARE INCREASINGLY INTERESTED IN EPIGENETIC FACTORS SUCH AS DNA METHYLATION, BECAUSE THEY PLAY AN IMPORTANT ROLE IN REGULATING GENE EXPRESSION WITHOUT CHANGES IN THE DNA SEQUENCE. THERE HAVE BEEN SIGNIFICANT ADVANCES IN DEVELOPING STATISTICAL METHODS TO DETECT DIFFERENTIALLY METHYLATED REGIONS (DMRS) ASSOCIATED WITH BINARY DISEASE STATUS. MOST OF THESE METHODS ARE BEING DEVELOPED FOR DETECTING DIFFERENTIAL METHYLATION RATES BETWEEN CASES AND CONTROLS. WE CONSIDER MULTIPLE SEVERITY LEVELS OF DISEASE, AND DEVELOP A BAYESIAN STATISTICAL METHOD TO DETECT THE REGION WITH INCREASING (OR DECREASING) METHYLATION RATES AS THE DISEASE SEVERITY INCREASES. PATIENTS ARE CLASSIFIED INTO MORE THAN TWO GROUPS, BASED ON THE DISEASE SEVERITY (E.G., STAGES OF CANCER), AND DMRS ARE DETECTED BY USING MOVING WINDOWS ALONG THE GENOME. WITHIN EACH WINDOW, THE BAYES FACTOR IS CALCULATED TO TEST THE HYPOTHESIS OF MONOTONIC INCREASE IN METHYLATION RATES CORRESPONDING TO SEVERITY OF THE DISEASE VERSUS NO DIFFERENCE. A MIXED-EFFECT MODEL IS USED TO INCORPORATE THE CORRELATION OF METHYLATION RATES OF NEARBY CPG SITES IN THE REGION. RESULTS FROM EXTENSIVE SIMULATION INDICATE THAT OUR PROPOSED METHOD IS STATISTICALLY VALID AND REASONABLY POWERFUL. WE DEMONSTRATE OUR APPROACH ON A BISULFITE SEQUENCING DATASET FROM A CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) STUDY. 2019 3 381 37 AN EPIGENOME-WIDE ASSOCIATION STUDY OF EARLY-ONSET MAJOR DEPRESSION IN MONOZYGOTIC TWINS. MAJOR DEPRESSION (MD) IS A DEBILITATING MENTAL HEALTH CONDITION WITH PEAK PREVALENCE OCCURRING EARLY IN LIFE. GENOME-WIDE EXAMINATION OF DNA METHYLATION (DNAM) OFFERS AN ATTRACTIVE COMPLEMENT TO STUDIES OF ALLELIC RISK GIVEN IT CAN REFLECT THE COMBINED INFLUENCE OF GENES AND ENVIRONMENT. THE CURRENT STUDY USED MONOZYGOTIC TWINS TO IDENTIFY DIFFERENTIALLY AND VARIABLY METHYLATED REGIONS OF THE GENOME THAT DISTINGUISH TWINS WITH AND WITHOUT A LIFETIME HISTORY OF EARLY-ONSET MD. THE SAMPLE INCLUDED 150 CAUCASIAN MONOZYGOTIC TWINS BETWEEN THE AGES OF 15 AND 20 (73% FEMALE; MAGE = 17.52 SD = 1.28) WHO WERE ASSESSED DURING A DEVELOPMENTAL STAGE CHARACTERIZED BY RELATIVELY DISTINCT NEUROPHYSIOLOGICAL CHANGES. ALL TWINS WERE GENERALLY HEALTHY AND CURRENTLY FREE OF MEDICATIONS WITH PSYCHOTROPIC EFFECTS. DNAM WAS MEASURED IN PERIPHERAL BLOOD CELLS USING THE INFINIUM HUMAN BEADCHIP 450 K ARRAY. MD ASSOCIATIONS WITH EARLY-ONSET MD WERE DETECTED AT 760 DIFFERENTIALLY AND VARIABLY METHYLATED PROBES/REGIONS THAT MAPPED TO 428 GENES. GENES AND GENOMIC REGIONS INVOLVED NEURAL CIRCUITRY FORMATION, PROJECTION, FUNCTIONING, AND PLASTICITY. GENE ENRICHMENT ANALYSES IMPLICATED GENES RELATED TO NEURON STRUCTURES AND NEURODEVELOPMENTAL PROCESSES INCLUDING CELL-CELL ADHESION GENES (E.G., PCDHA GENES). GENES PREVIOUSLY IMPLICATED IN MOOD AND PSYCHIATRIC DISORDERS AS WELL AS CHRONIC STRESS (E.G., NRG3) ALSO WERE IDENTIFIED. DNAM REGIONS ASSOCIATED WITH EARLY-ONSET MD WERE FOUND TO OVERLAP GENETIC LOCI IDENTIFIED IN THE LATEST PSYCHIATRIC GENOMICS CONSORTIUM META-ANALYSIS OF DEPRESSION. UNDERSTANDING THE TIME COURSE OF EPIGENETIC INFLUENCES DURING EMERGING ADULTHOOD MAY CLARIFY DEVELOPMENTAL PHASES WHERE CHANGES IN THE DNA METHYLOME MAY MODULATE INDIVIDUAL DIFFERENCES IN MD RISK. 2020 4 1436 38 DIFFERENTIAL METHYLATION OF THE TRPA1 PROMOTER IN PAIN SENSITIVITY. CHRONIC PAIN IS A GLOBAL PUBLIC HEALTH PROBLEM, BUT THE UNDERLYING MOLECULAR MECHANISMS ARE NOT FULLY UNDERSTOOD. HERE WE EXAMINE GENOME-WIDE DNA METHYLATION, FIRST IN 50 IDENTICAL TWINS DISCORDANT FOR HEAT PAIN SENSITIVITY AND THEN IN 50 FURTHER UNRELATED INDIVIDUALS. WHOLE-BLOOD DNA METHYLATION WAS CHARACTERIZED AT 5.2 MILLION LOCI BY MEDIP SEQUENCING AND ASSESSED LONGITUDINALLY TO IDENTIFY DIFFERENTIALLY METHYLATED REGIONS ASSOCIATED WITH HIGH OR LOW PAIN SENSITIVITY (PAIN DMRS). NINE META-ANALYSIS PAIN DMRS SHOW ROBUST EVIDENCE FOR ASSOCIATION (FALSE DISCOVERY RATE 5%) WITH THE STRONGEST SIGNAL IN THE PAIN GENE TRPA1 (P=1.2 X 10(-13)). SEVERAL PAIN DMRS SHOW LONGITUDINAL STABILITY CONSISTENT WITH SUSCEPTIBILITY EFFECTS, HAVE SIMILAR METHYLATION LEVELS IN THE BRAIN AND ALTERED EXPRESSION IN THE SKIN. OUR APPROACH IDENTIFIES EPIGENETIC CHANGES IN BOTH NOVEL AND ESTABLISHED CANDIDATE GENES THAT PROVIDE MOLECULAR INSIGHTS INTO PAIN AND MAY GENERALIZE TO OTHER COMPLEX TRAITS. 2014 5 1519 31 DNA METHYLATION AT ATP11A CG11702988 IS A BIOMARKER OF LUNG DISEASE SEVERITY IN CYSTIC FIBROSIS: A LONGITUDINAL STUDY. CYSTIC FIBROSIS (CF) IS A CHRONIC GENETIC DISEASE THAT MAINLY AFFECTS THE RESPIRATORY AND GASTROINTESTINAL SYSTEMS. NO CURATIVE TREATMENTS ARE AVAILABLE, BUT THE FOLLOW-UP IN SPECIALIZED CENTERS HAS GREATLY IMPROVED THE PATIENT LIFE EXPECTANCY. ROBUST BIOMARKERS ARE REQUIRED TO MONITOR THE DISEASE, GUIDE TREATMENTS, STRATIFY PATIENTS, AND PROVIDE OUTCOME MEASURES IN CLINICAL TRIALS. IN THE PRESENT STUDY, WE OUTLINE A STRATEGY TO SELECT PUTATIVE DNA METHYLATION BIOMARKERS OF LUNG DISEASE SEVERITY IN CYSTIC FIBROSIS PATIENTS. IN THE DISCOVERY STEP, WE SELECTED SEVEN POTENTIAL BIOMARKERS USING A GENOME-WIDE DNA METHYLATION DATASET THAT WE GENERATED IN NASAL EPITHELIAL SAMPLES FROM THE METHYLCF COHORT. IN THE REPLICATION STEP, WE ASSESSED THE SAME BIOMARKERS USING SPUTUM CELL SAMPLES FROM THE METHYLBIOMARK COHORT. OF INTEREST, DNA METHYLATION AT THE CG11702988 SITE (ATP11A GENE) POSITIVELY CORRELATED WITH LUNG FUNCTION AND BMI, AND NEGATIVELY CORRELATED WITH LUNG DISEASE SEVERITY, P. AERUGINOSA CHRONIC INFECTION, AND THE NUMBER OF EXACERBATIONS. THESE RESULTS WERE REPLICATED IN PROSPECTIVE SPUTUM SAMPLES COLLECTED AT FOUR TIME POINTS WITHIN AN 18-MONTH PERIOD AND LONGITUDINALLY. TO CONCLUDE, (I) WE IDENTIFIED A DNA METHYLATION BIOMARKER THAT CORRELATES WITH CF SEVERITY, (II) WE PROVIDED A METHOD TO EASILY ASSESS THIS BIOMARKER, AND (III) WE CARRIED OUT THE FIRST LONGITUDINAL ANALYSIS OF DNA METHYLATION IN CF PATIENTS. THIS NEW EPIGENETIC BIOMARKER COULD BE USED TO STRATIFY CF PATIENTS IN CLINICAL TRIALS. 2021 6 3652 38 INDIVIDUAL DNA METHYLATION PATTERN SHIFTS IN NANOPARTICLES-EXPOSED WORKERS ANALYZED IN FOUR CONSECUTIVE YEARS. A DNA METHYLATION PATTERN REPRESENTS AN ORIGINAL PLAN OF THE FUNCTION SETTINGS OF INDIVIDUAL CELLS AND TISSUES. THE BASIC STRATEGIES OF ITS DEVELOPMENT AND CHANGES DURING THE HUMAN LIFETIME ARE KNOWN, BUT THE DETAILS RELATED TO ITS MODIFICATION OVER THE YEARS ON AN INDIVIDUAL BASIS HAVE NOT YET BEEN STUDIED. MOREOVER, CURRENT EVIDENCE SHOWS THAT ENVIRONMENTAL EXPOSURE COULD GENERATE CHANGES IN DNA METHYLATION SETTINGS AND, SUBSEQUENTLY, THE FUNCTION OF GENES. IN THIS STUDY, WE ANALYZED THE EFFECT OF CHRONIC EXPOSURE TO NANOPARTICLES (NP) IN OCCUPATIONALLY EXPOSED WORKERS REPEATEDLY SAMPLED IN FOUR CONSECUTIVE YEARS (2016-2019). A DETAILED METHYLATION PATTERN ANALYSIS OF 14 PERSONS (10 EXPOSED AND 4 CONTROLS) WAS PERFORMED ON AN INDIVIDUAL BASIS. A MICROARRAY-BASED APPROACH USING CHIPS, ALLOWING THE ASSESSMENT OF MORE THAN 850 K CPG LOCI, WAS USED. INDIVIDUAL DNA METHYLATION PATTERNS WERE COMPARED BY PRINCIPAL COMPONENT ANALYSIS (PCA). THE RESULTS SHOW THE SHIFT IN DNA METHYLATION PATTERNS IN INDIVIDUAL YEARS IN ALL THE EXPOSED AND CONTROL SUBJECTS. THE OVERALL RANGE OF DIFFERENCES VARIED BETWEEN THE YEARS IN INDIVIDUAL PERSONS. THE DIFFERENCES BETWEEN THE FIRST AND LAST YEAR OF EXAMINATION (A THREE-YEAR TIME PERIOD) SEEM TO BE CONSISTENTLY GREATER IN THE NP-EXPOSED SUBJECTS IN COMPARISON WITH THE CONTROLS. THE SELECTED 14 MOST DIFFERENTLY METHYLATED CG LOCI WERE RELATIVELY STABLE IN THE CHRONICALLY EXPOSED SUBJECTS. IN SUMMARY, THE SPECIFIC TYPE OF LONG-TERM EXPOSURE CAN CONTRIBUTE TO THE FIXING OF RELEVANT EPIGENETIC CHANGES RELATED TO A SPECIFIC ENVIRONMENT AS, E.G., NP INHALATION. 2021 7 1537 26 DNA METHYLATION IN ADOLESCENTS WITH ANXIETY DISORDER: A LONGITUDINAL STUDY. ANXIETY DISORDERS (AD) TYPICALLY MANIFEST IN CHILDREN AND ADOLESCENTS AND MIGHT PERSIST INTO ADULTHOOD. HOWEVER, THERE ARE STILL FEW DATA CONCERNING EPIGENETIC MECHANISMS ASSOCIATED WITH ONSET, PERSISTENCE OR REMISSION OF AD OVER TIME. WE INVESTIGATED A COHORT OF ADOLESCENTS AND YOUNG ADULTS AT BASELINE (AGE; 13.19 +/- 2.38) AND AFTER 5 YEARS AND CLASSIFIED THEM ACCORDING TO THE AD DIAGNOSIS AND THEIR LONGITUDINAL TRAJECTORIES INTO 4 GROUPS: (1) TYPICALLY DEVELOPING COMPARISONS (TDC; CONTROL GROUP, N = 14); (2) INCIDENT (AD IN THE SECOND EVALUATION ONLY, N = 11); (3) PERSISTENT (AD IN BOTH EVALUATIONS, N = 14) AND (4) REMITTENT (AD IN THE FIRST EVALUATION ONLY, N = 8). DNA METHYLATION WAS EVALUATED WITH THE INFINIUM HUMANMETHYLATION450 BEADCHIP FROM SALIVA SAMPLES COLLECTED AT BOTH EVALUATIONS. GENE SET ENRICHMENT ANALYSIS WAS APPLIED TO CONSIDER BIOLOGICAL PATHWAYS. WE FOUND DECREASED DNA METHYLATION IN TDC GROUP WHILE THE CHRONIC CASES OF AD PRESENTED HYPERMETHYLATION IN CENTRAL NERVOUS SYSTEM DEVELOPMENT PATHWAYS. MOREOVER, WE SHOWED THAT THIS PERSISTENT GROUP ALSO PRESENTED HYPERMETHYLATION WHILE THE OTHER THREE GROUPS WERE ASSOCIATED WITH HYPOMETHYLATION IN NERVOUS SYSTEM DEVELOPMENT PATHWAY. INCIDENCE AND REMISSION GROUPS WERE ASSOCIATED WITH INCREASED AND DECREASED METHYLATION IN NEURON DEVELOPMENT PATHWAYS, RESPECTIVELY. LARGER STUDIES ARE LIKELY TO DETECT SPECIFIC GENES RELEVANT TO AD. 2018 8 1607 31 DNA METHYLATION, COLON CANCER AND MEDITERRANEAN DIET: RESULTS FROM THE EPIC-ITALY COHORT. THE BIOLOGICAL MECHANISMS THROUGH WHICH ADHERENCE TO MEDITERRANEAN DIET (MD) PROTECTS AGAINST COLON CANCER (CC) ARE POORLY UNDERSTOOD. EVIDENCE SUGGESTS THAT CHRONIC INFLAMMATION MAY BE IMPLICATED IN THE PATHWAY. BOTH DIET AND CC ARE RELATED TO EPIGENETIC REGULATION. WE PERFORMED A NESTED CASE-CONTROL STUDY ON 161 PAIRS FROM THE ITALIAN COMPONENT OF THE EUROPEAN PROSPECTIVE INVESTIGATION INTO CANCER AND NUTRITION (EPIC) COHORT, IN WHICH WE LOOKED FOR THE METHYLATION SIGNALS IN DNA EXTRACTED FROM LEUCOCYTES ASSOCIATED WITH BOTH CC AND MD IN 995 CPGS LOCATED IN 48 INFLAMMATION GENES. THE DNA METHYLATION SIGNALS DETECTED IN THIS ANALYSIS WERE VALIDATED IN A SUBGROUP OF 47 CASE-CONTROL PAIRS AND FURTHER REPLICATED (WHERE VALIDATED) IN 95 NEW PAIRS BY MEANS OF PYROSEQUENCING. AMONG THE CPG SITES SELECTED A-PRIORI IN INFLAMMATION-RELATED GENES, SEVEN CPG SITES WERE FOUND TO BE ASSOCIATED WITH CC STATUS AND WITH MD, IN LINE WITH ITS PROTECTIVE EFFECT. ONLY TWO CPG SITES (CG17968347-SERPINE1 AND CG20674490-RUNX3) WERE VALIDATED USING BISULPHITE PYROSEQUENCING AND, AFTER REPLICATION, WE FOUND THAT DNA METHYLATION OF CG20674490-RUNX3 MAY BE A POTENTIAL MOLECULAR MEDIATOR EXPLAINING THE PROTECTIVE EFFECT OF MD ON CC ONSET. THE USE OF A 'MEET-IN-THE-MIDDLE' APPROACH TO IDENTIFY THE OVERLAP BETWEEN EXPOSURE AND PREDICTIVE MARKERS OF DISEASE IS INNOVATIVE IN STUDIES ON THE RELATIONSHIP BETWEEN DIET AND CANCER, IN WHICH EXPOSURE ASSESSMENT IS DIFFICULT AND THE MECHANISMS THROUGH WHICH THE NUTRIENTS EXERT THEIR PROTECTIVE EFFECT IS LARGELY UNKNOWN. 2019 9 3077 32 GENOME-WIDE METHYL-SEQ ANALYSIS OF BLOOD-BRAIN TARGETS OF GLUCOCORTICOID EXPOSURE. CHRONIC EXPOSURE TO GLUCOCORTICOIDS (GCS) CAN LEAD TO PSYCHIATRIC COMPLICATIONS THROUGH EPIGENETIC MECHANISMS SUCH AS DNA METHYLATION (DNAM). WE SOUGHT TO DETERMINE WHETHER EPIGENETIC CHANGES IN A PERIPHERAL TISSUE CAN SERVE AS A SURROGATE FOR THOSE IN A RELATIVELY INACCESSIBLE TISSUE SUCH AS THE BRAIN. DNA EXTRACTED FROM THE HIPPOCAMPUS AND BLOOD OF MICE TREATED WITH GCS OR VEHICLE SOLUTION WAS ASSAYED USING A GENOME-WIDE DNAM PLATFORM (METHYL-SEQ) TO IDENTIFY DIFFERENTIALLY METHYLATED REGIONS (DMRS) INDUCED BY GC TREATMENT. WE OBSERVED THAT APPROXIMATELY 70% OF THE DMRS IN BOTH TISSUES LOST METHYLATION FOLLOWING GC TREATMENT. OF THE 3,095 DMRS THAT MAPPED TO THE SAME GENES IN BOTH TISSUES, 1,853 DMRS UNDERWENT DNAM CHANGES IN THE SAME DIRECTION. INTERESTINGLY, ONLY 209 DMRS (<7%) OVERLAPPED IN GENOMIC COORDINATES BETWEEN THE 2 TISSUES, SUGGESTING TISSUE-SPECIFIC DIFFERENCES IN GC-TARGETED LOCI. PATHWAY ANALYSIS SHOWED THAT THE DMR-ASSOCIATED GENES WERE MEMBERS OF PATHWAYS INVOLVED IN METABOLISM, IMMUNE FUNCTION, AND NEURODEVELOPMENT. ALSO, CHANGES IN CELL TYPE COMPOSITION OF BLOOD AND BRAIN WERE EXAMINED BY FLUORESCENCE-ACTIVATED CELL SORTING. SEPARATION OF THE CORTEX INTO NEURONAL AND NON-NEURONAL FRACTIONS AND THE LEUKOCYTES INTO T-CELLS, B-CELLS, AND NEUTROPHILS SHOWED THAT GC-INDUCED METHYLATION CHANGES PRIMARILY OCCURRED IN NEURONS AND T-CELLS, WITH THE BLOOD TISSUE ALSO UNDERGOING A SHIFT IN THE PROPORTION OF CONSTITUENT CELL TYPES WHILE THE PROPORTION OF NEURONS AND GLIA IN THE BRAIN REMAINED STABLE. FROM THE CURRENT PILOT STUDY, WE FOUND THAT DESPITE TISSUE-SPECIFIC EPIGENETIC CHANGES AND CELLULAR HETEROGENEITY, BLOOD CAN SERVE AS A SURROGATE FOR GC-INDUCED CHANGES IN THE BRAIN. 2017 10 1739 34 EARLY DNA METHYLATION CHANGES IN CHILDREN DEVELOPING BETA CELL AUTOIMMUNITY AT A YOUNG AGE. AIMS/HYPOTHESIS: TYPE 1 DIABETES IS A CHRONIC AUTOIMMUNE DISEASE OF COMPLEX AETIOLOGY, INCLUDING A POTENTIAL ROLE FOR EPIGENETIC REGULATION. PREVIOUS EPIGENOMIC STUDIES FOCUSED MAINLY ON CLINICALLY DIAGNOSED INDIVIDUALS. THE AIM OF THE STUDY WAS TO ASSESS EARLY DNA METHYLATION CHANGES ASSOCIATED WITH TYPE 1 DIABETES ALREADY BEFORE THE DIAGNOSIS OR EVEN BEFORE THE APPEARANCE OF AUTOANTIBODIES. METHODS: REDUCED REPRESENTATION BISULPHITE SEQUENCING (RRBS) WAS APPLIED TO STUDY DNA METHYLATION IN PURIFIED CD4(+) T CELL, CD8(+) T CELL AND CD4(-)CD8(-) CELL FRACTIONS OF 226 PERIPHERAL BLOOD MONONUCLEAR CELL SAMPLES LONGITUDINALLY COLLECTED FROM SEVEN TYPE 1 DIABETES-SPECIFIC AUTOANTIBODY-POSITIVE INDIVIDUALS AND CONTROL INDIVIDUALS MATCHED FOR AGE, SEX, HLA RISK AND PLACE OF BIRTH. WE ALSO EXPLORED CORRELATIONS BETWEEN DNA METHYLATION AND GENE EXPRESSION USING RNA SEQUENCING DATA FROM THE SAME SAMPLES. TECHNICAL VALIDATION OF RRBS RESULTS WAS PERFORMED USING PYROSEQUENCING. RESULTS: WE IDENTIFIED 79, 56 AND 45 DIFFERENTIALLY METHYLATED REGIONS IN CD4(+) T CELLS, CD8(+) T CELLS AND CD4(-)CD8(-) CELL FRACTIONS, RESPECTIVELY, BETWEEN TYPE 1 DIABETES-SPECIFIC AUTOANTIBODY-POSITIVE INDIVIDUALS AND CONTROL PARTICIPANTS. THE ANALYSIS OF PRE-SEROCONVERSION SAMPLES IDENTIFIED DNA METHYLATION SIGNATURES AT THE VERY EARLY STAGE OF DISEASE, INCLUDING DIFFERENTIAL METHYLATION AT THE PROMOTER OF IRF5 IN CD4(+) T CELLS. FURTHER, WE VALIDATED RRBS RESULTS USING PYROSEQUENCING AT THE FOLLOWING CPG SITES: CHR19:18118304 IN THE PROMOTER OF ARRDC2; CHR21:47307815 IN THE INTRON OF PCBP3; AND CHR14:81128398 IN THE INTERGENIC REGION NEAR TRAF3 IN CD4(+) T CELLS. CONCLUSIONS/INTERPRETATION: THESE PRELIMINARY RESULTS PROVIDE NOVEL INSIGHTS INTO CELL TYPE-SPECIFIC DIFFERENTIAL EPIGENETIC REGULATION OF GENES, WHICH MAY CONTRIBUTE TO TYPE 1 DIABETES PATHOGENESIS AT THE VERY EARLY STAGE OF DISEASE DEVELOPMENT. SHOULD THESE FINDINGS BE VALIDATED, THEY MAY SERVE AS A POTENTIAL SIGNATURE USEFUL FOR DISEASE PREDICTION AND MANAGEMENT. 2022 11 1696 37 DYNAMIC DNA METHYLATION CHANGES IN EARLY VERSUS LATE ADULTHOOD SUGGEST NONDETERMINISTIC EFFECTS OF CHILDHOOD ADVERSITY: A META-ANALYSIS. ADVERSE CHILDHOOD EXPERIENCES (ACES) ARE ASSOCIATED WITH A HIGH RISK OF DEVELOPING CHRONIC DISEASES AND DECREASED LIFE EXPECTANCY, BUT NO ACE EPIGENETIC BIOMARKERS HAVE BEEN IDENTIFIED UNTIL NOW. THE LATTER MAY RESULT FROM THE INTERACTION OF MULTIPLE FACTORS SUCH AS AGE, SEX, DEGREE OF ADVERSITY, AND LACK OF TRANSCRIPTIONAL EFFECTS OF DNA METHYLATION CHANGES. WE HYPOTHESIZE THAT DNA METHYLATION CHANGES ARE RELATED TO CHILDHOOD ADVERSITY LEVELS AND CURRENT AGE, AND THESE MARKERS EVOLVE AS AGING PROCEEDS. TWO GENE EXPRESSION OMNIBUS DATASETS, REGARDING ACE, WERE SELECTED (GSE72680 AND GSE70603), CONSIDERING RAW- AND META-DATA AVAILABILITY, INCLUDING VALIDATED ACE INDEX (CHILDHOOD TRAUMA QUESTIONNAIRE (CTQ) SCORE). FOR DNA METHYLATION, ANALYZED PROBES WERE RESTRICTED TO THOSE LAYING WITHIN PROMOTERS AND FIRST EXONS, AND SAMPLES WERE GROUPED BY CTQ SCORES TERCILES, TO COMPARE HIGHLY (ACE) WITH NON-ABUSED (CONTROL) CASES. COMPARISON OF CONTROL AND ACE METHYLOME PROFILE DID NOT RETRIEVE DIFFERENTIALLY METHYLATED CPG SITES (DMCS) AFTER CORRECTING BY FALSE DISCOVERY RATE < 0.05, AND THIS WAS ALSO OBSERVED WHEN SAMPLES WERE SEPARATED BY SEX. IN CONTRAST, GROUPING BY DECADE AGE RANGES (I.E., THE 20S, 30S, 40S, AND 50S) SHOWED A PROGRESSIVE INCREASE IN THE NUMBER OF DMCS AND THE INTENSITY OF CHANGES, MAINLY RELATED WITH HYPOMETHYLATION. COMPARISON WITH TRANSCRIPTOME DATA FOR ACE SUBJECTS IN THE 40S, AND 50S SHOWED A SIMILAR AGE-DEPENDENT EFFECT. THIS STUDY PROVIDES EVIDENCE THAT EPIGENETIC MARKERS OF ACE ARE AGE-DEPENDENT, BUT NOT DEFINED IN THE LONG TERM. THESE DIFFERENCES AMONG EARLY, MIDDLE, AND LATE ADULTHOOD EPIGENOMIC PROFILES SUGGEST A WINDOW FOR INTERVENTIONS AIMED TO PREVENT THE DETRIMENTAL EFFECTS OF ACE. 2021 12 1579 36 DNA METHYLATION PROFILE OF LIVER OF MICE CONCEIVED BY IN VITRO FERTILIZATION. OFFSPRING GENERATED BY IN VITRO FERTILIZATION (IVF) ARE BELIEVED TO BE HEALTHY BUT DISPLAY A POSSIBLE PREDISPOSITION TO CHRONIC DISEASES, LIKE HYPERTENSION AND GLUCOSE INTOLERANCE. SINCE EPIGENETIC CHANGES ARE BELIEVED TO UNDERLIE SUCH PHENOTYPE, THIS STUDY AIMED AT DESCRIBING GLOBAL DNA METHYLATION CHANGES IN THE LIVER OF ADULT MICE GENERATED BY NATURAL MATING (FB GROUP) OR BY IVF. EMBRYOS WERE GENERATED BY IVF OR NATURAL MATING. AT 30 WEEKS OF AGE, MICE WERE SACRIFICED. THE LIVER WAS REMOVED, AND GLOBAL DNA METHYLATION WAS ASSESSED USING WHOLE-GENOME BISULFITE SEQUENCING (WGBS). GENOMIC REGIONS FOR ENRICHMENT ANALYSIS TOOL (GREAT) AND G:PROFILERBETA WERE USED TO IDENTIFY DIFFERENTIALLY METHYLATED REGIONS (DMRS) AND FOR FUNCTIONAL ENRICHMENT ANALYSIS. OVERREPRESENTED GENE ONTOLOGY TERMS WERE SUMMARIZED WITH REVIGO, WHILE CANONICAL PATHWAYS (CPS) WERE IDENTIFIED WITH INGENUITY(R) PATHWAY ANALYSIS. OVERALL, 2692 DMRS (4.91%) WERE DIFFERENT BETWEEN THE GROUPS. THE MAJORITY OF DMRS (84.92%) WERE HYPOMETHYLATED IN THE IVF GROUP. SURPRISINGLY, ONLY 0.16% OF CPG ISLANDS WERE DIFFERENTIALLY METHYLATED AND ONLY A FEW DMRS WERE LOCATED ON KNOWN GENE PROMOTERS (N = 283) OR ENHANCERS (N = 190). NOTABLY, THE LONG-INTERSPERSED ELEMENT (LINE), SHORT-INTERSPERSED ELEMENT (SINE), AND LONG TERMINAL REPEAT (LTR1) TRANSPOSABLE ELEMENTS SHOWED REDUCED METHYLATION (P < 0.05) IN IVF LIVERS. CELLULAR METABOLIC PROCESS, HEPATIC FIBROSIS, AND INSULIN RECEPTOR SIGNALING WERE SOME OF THE PRINCIPAL BIOLOGICAL PROCESSES AND CPS MODIFIED BY IVF. IN SUMMARY, IVF MODIFIES THE DNA METHYLATION SIGNATURE IN THE ADULT LIVER, RESULTING IN HYPOMETHYLATION OF GENES INVOLVED IN METABOLISM AND GENE TRANSCRIPTION REGULATION. THESE FINDINGS MAY SHED LIGHT ON THE MECHANISMS UNDERLYING THE DEVELOPMENTAL ORIGIN OF HEALTH AND DISEASE. 2022 13 1503 35 DNA METHYLATION AND GENE EXPRESSION DIFFERENCES IN CHILDREN CONCEIVED IN VITRO OR IN VIVO. EPIDEMIOLOGICAL DATA INDICATE THAT CHILDREN CONCEIVED IN VITRO HAVE A GREATER RELATIVE RISK OF LOW BIRTH-WEIGHT, MAJOR AND MINOR BIRTH DEFECTS, AND RARE DISORDERS INVOLVING IMPRINTED GENES, SUGGESTING THAT EPIGENETIC CHANGES MAY BE ASSOCIATED WITH ASSISTED REPRODUCTION. WE EXAMINED DNA METHYLATION AT MORE THAN 700 GENES (1536 CPG SITES) IN PLACENTA AND CORD BLOOD AND MEASURED GENE EXPRESSION LEVELS OF A SUBSET OF GENES THAT DIFFERED IN METHYLATION LEVELS BETWEEN CHILDREN CONCEIVED IN VITRO VERSUS IN VIVO. OUR RESULTS SUGGEST THAT IN VITRO CONCEPTION IS ASSOCIATED WITH LOWER MEAN METHYLATION AT CPG SITES IN PLACENTA AND HIGHER MEAN METHYLATION AT CPG SITES IN CORD BLOOD. WE ALSO FIND THAT IN VITRO CONCEPTION-ASSOCIATED DNA METHYLATION DIFFERENCES ARE ASSOCIATED WITH GENE EXPRESSION DIFFERENCES AT BOTH IMPRINTED AND NON-IMPRINTED GENES. THE RANGE OF INTER-INDIVIDUAL VARIATION IN GENE EXPRESSION OF THE IN VITRO AND IN VIVO GROUPS OVERLAPS SUBSTANTIALLY BUT SOME INDIVIDUALS FROM THE IN VITRO GROUP DIFFER FROM THE IN VIVO GROUP MEAN BY MORE THAN TWO STANDARD DEVIATIONS. SEVERAL OF THE GENES WHOSE EXPRESSION DIFFERS BETWEEN THE TWO GROUPS HAVE BEEN IMPLICATED IN CHRONIC METABOLIC DISORDERS, SUCH AS OBESITY AND TYPE II DIABETES. THESE FINDINGS SUGGEST THAT THERE MAY BE EPIGENETIC DIFFERENCES IN THE GAMETES OR EARLY EMBRYOS DERIVED FROM COUPLES UNDERGOING TREATMENT FOR INFERTILITY. ALTERNATIVELY, ASSISTED REPRODUCTION TECHNOLOGY MAY HAVE AN EFFECT ON GLOBAL PATTERNS OF DNA METHYLATION AND GENE EXPRESSION. IN EITHER CASE, THESE DIFFERENCES OR CHANGES MAY AFFECT LONG-TERM PATTERNS OF GENE EXPRESSION. 2009 14 2820 27 FINE-MAPPING INFLAMMATORY BOWEL DISEASE LOCI TO SINGLE-VARIANT RESOLUTION. INFLAMMATORY BOWEL DISEASES ARE CHRONIC GASTROINTESTINAL INFLAMMATORY DISORDERS THAT AFFECT MILLIONS OF PEOPLE WORLDWIDE. GENOME-WIDE ASSOCIATION STUDIES HAVE IDENTIFIED 200 INFLAMMATORY BOWEL DISEASE-ASSOCIATED LOCI, BUT FEW HAVE BEEN CONCLUSIVELY RESOLVED TO SPECIFIC FUNCTIONAL VARIANTS. HERE WE REPORT FINE-MAPPING OF 94 INFLAMMATORY BOWEL DISEASE LOCI USING HIGH-DENSITY GENOTYPING IN 67,852 INDIVIDUALS. WE PINPOINT 18 ASSOCIATIONS TO A SINGLE CAUSAL VARIANT WITH GREATER THAN 95% CERTAINTY, AND AN ADDITIONAL 27 ASSOCIATIONS TO A SINGLE VARIANT WITH GREATER THAN 50% CERTAINTY. THESE 45 VARIANTS ARE SIGNIFICANTLY ENRICHED FOR PROTEIN-CODING CHANGES (N = 13), DIRECT DISRUPTION OF TRANSCRIPTION-FACTOR BINDING SITES (N = 3), AND TISSUE-SPECIFIC EPIGENETIC MARKS (N = 10), WITH THE LAST CATEGORY SHOWING ENRICHMENT IN SPECIFIC IMMUNE CELLS AMONG ASSOCIATIONS STRONGER IN CROHN'S DISEASE AND IN GUT MUCOSA AMONG ASSOCIATIONS STRONGER IN ULCERATIVE COLITIS. THE RESULTS OF THIS STUDY SUGGEST THAT HIGH-RESOLUTION FINE-MAPPING IN LARGE SAMPLES CAN CONVERT MANY DISCOVERIES FROM GENOME-WIDE ASSOCIATION STUDIES INTO STATISTICALLY CONVINCING CAUSAL VARIANTS, PROVIDING A POWERFUL SUBSTRATE FOR EXPERIMENTAL ELUCIDATION OF DISEASE MECHANISMS. 2017 15 2653 34 EPIGENOTYPING IN PERIPHERAL BLOOD CELL DNA AND BREAST CANCER RISK: A PROOF OF PRINCIPLE STUDY. BACKGROUND: EPIGENETIC CHANGES ARE EMERGING AS ONE OF THE MOST IMPORTANT EVENTS IN CARCINOGENESIS. TWO ALTERATIONS IN THE PATTERN OF DNA METHYLATION IN BREAST CANCER (BC) HAVE BEEN PREVIOUSLY REPORTED; ACTIVE ESTROGEN RECEPTOR-ALPHA (ER-ALPHA) IS ASSOCIATED WITH DECREASED METHYLATION OF ER-ALPHA TARGET (ERT) GENES, AND POLYCOMB GROUP TARGET (PCGT) GENES ARE MORE LIKELY THAN OTHER GENES TO HAVE PROMOTER DNA HYPERMETHYLATION IN CANCER. HOWEVER, WHETHER DNA METHYLATION IN NORMAL UNRELATED CELLS IS ASSOCIATED WITH BC RISK AND WHETHER THESE IMPRINTS CAN BE RELATED TO FACTORS WHICH CAN BE MODIFIED BY THE ENVIRONMENT, IS UNCLEAR. METHODOLOGY/PRINCIPAL FINDINGS: USING QUANTITATIVE METHYLATION ANALYSIS IN A CASE-CONTROL STUDY (N = 1,083) WE FOUND THAT DNA METHYLATION OF PERIPHERAL BLOOD CELL DNA PROVIDES GOOD PREDICTION OF BC RISK. WE ALSO REPORT THAT INVASIVE DUCTAL AND INVASIVE LOBULAR BC IS CHARACTERIZED BY TWO DIFFERENT SETS OF GENES, THE LATTER PARTICULAR BY GENES INVOLVED IN THE DIFFERENTIATION OF THE MESENCHYME (PITX2, TITF1, GDNF AND MYOD1). FINALLY WE DEMONSTRATE THAT ONLY ERT GENES PREDICT ER POSITIVE BC; LACK OF PERIPHERAL BLOOD CELL DNA METHYLATION OF ZNF217 PREDICTED BC INDEPENDENT OF AGE AND FAMILY HISTORY (ODDS RATIO 1.49; 95% CONFIDENCE INTERVAL 1.12-1.97; P = 0.006) AND WAS ASSOCIATED WITH ER-ALPHA BIOACTIVITY IN THE CORRESPONDING SERUM. CONCLUSION/SIGNIFICANCE: THIS FIRST LARGE-SCALE EPIGENOTYPING STUDY DEMONSTRATES THAT DNA METHYLATION MAY SERVE AS A LINK BETWEEN THE ENVIRONMENT AND THE GENOME. FACTORS THAT CAN BE MODULATED BY THE ENVIRONMENT (LIKE ESTROGENS) LEAVE AN IMPRINT IN THE DNA OF CELLS THAT ARE UNRELATED TO THE TARGET ORGAN AND INDICATE THE PREDISPOSITION TO DEVELOP A CANCER. FURTHER RESEARCH WILL NEED TO DEMONSTRATE WHETHER DNA METHYLATION PROFILES WILL BE ABLE TO SERVE AS A NEW TOOL TO PREDICT THE RISK OF DEVELOPING CHRONIC DISEASES WITH SUFFICIENT ACCURACY TO GUIDE PREVENTIVE MEASURES. 2008 16 2079 31 EPIGENETIC DNA METHYLATION CHANGES ASSOCIATED WITH HEADACHE CHRONIFICATION: A RETROSPECTIVE CASE-CONTROL STUDY. BACKGROUND THE BIOLOGICAL MECHANISMS OF HEADACHE CHRONIFICATION ARE POORLY UNDERSTOOD. WE AIMED TO IDENTIFY CHANGES IN DNA METHYLATION ASSOCIATED WITH THE TRANSFORMATION FROM EPISODIC TO CHRONIC HEADACHE. METHODS PARTICIPANTS WERE RECRUITED FROM THE POPULATION-BASED NORWEGIAN HUNT STUDY. THIRTY-SIX FEMALE HEADACHE PATIENTS WHO TRANSFORMED FROM EPISODIC TO CHRONIC HEADACHE BETWEEN BASELINE AND FOLLOW-UP 11 YEARS LATER WERE MATCHED AGAINST 35 CONTROLS WITH EPISODIC HEADACHE. DNA METHYLATION WAS QUANTIFIED AT 485,000 CPG SITES, AND CHANGES IN METHYLATION LEVEL AT THESE SITES WERE COMPARED BETWEEN CASES AND CONTROLS BY LINEAR REGRESSION ANALYSIS. DATA WERE ANALYZED IN TWO STAGES (STAGES 1 AND 2) AND IN A COMBINED META-ANALYSIS. RESULTS NONE OF THE TOP 20 CPG SITES IDENTIFIED IN STAGE 1 REPLICATED IN STAGE 2 AFTER MULTIPLE TESTING CORRECTION. IN THE COMBINED META-ANALYSIS THE STRONGEST ASSOCIATED CPG SITES WERE RELATED TO SH2D5 AND NPTX2, TWO BRAIN-EXPRESSED GENES INVOLVED IN THE REGULATION OF SYNAPTIC PLASTICITY. FUNCTIONAL ENRICHMENT ANALYSIS POINTED TO PROCESSES INCLUDING CALCIUM ION BINDING AND ESTROGEN RECEPTOR PATHWAYS. CONCLUSION IN THIS FIRST GENOME-WIDE STUDY OF DNA METHYLATION IN HEADACHE CHRONIFICATION SEVERAL POTENTIALLY IMPLICATED LOCI AND PROCESSES WERE IDENTIFIED. THE STUDY EXEMPLIFIES THE USE OF PROSPECTIVELY COLLECTED POPULATION COHORTS TO SEARCH FOR EPIGENETIC MECHANISMS OF DISEASE. 2018 17 6547 33 TRANSCRIPTOMICS OF LONG-TERM MEDITATION PRACTICE: EVIDENCE FOR PREVENTION OR REVERSAL OF STRESS EFFECTS HARMFUL TO HEALTH. BACKGROUND AND OBJECTIVES: STRESS CAN OVERLOAD ADAPTIVE MECHANISMS, LEADING TO EPIGENETIC EFFECTS HARMFUL TO HEALTH. RESEARCH ON THE REVERSAL OF THESE EFFECTS IS IN ITS INFANCY. EARLY RESULTS SUGGEST SOME MEDITATION TECHNIQUES HAVE HEALTH BENEFITS THAT GROW WITH REPEATED PRACTICE. THIS STUDY FOCUSED ON POSSIBLE TRANSCRIPTOMIC EFFECTS OF 38 YEARS OF TWICE-DAILY TRANSCENDENTAL MEDITATION((R)) (TM((R))) PRACTICE. MATERIALS AND METHODS: FIRST, USING ILLUMINA((R)) BEADCHIP MICROARRAY TECHNOLOGY, DIFFERENCES IN GLOBAL GENE EXPRESSION IN PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMCS) WERE SOUGHT BETWEEN HEALTHY PRACTITIONERS AND TIGHTLY MATCHED CONTROLS (N = 12, AGE 65). SECOND, THESE MICROARRAY RESULTS WERE VERIFIED ON A SUBSET OF GENES USING QUANTITATIVE POLYMERASE CHAIN REACTION (QPCR) AND WERE VALIDATED USING QPCR IN LARGER TM AND CONTROL GROUPS (N = 45, AGE 63). BIOINFORMATICS INVESTIGATION EMPLOYED INGENUITY((R)) PATHWAY ANALYSIS (IPA((R))), DAVID, GENOMATIX, AND R PACKAGES. RESULTS: THE 200 GENES AND LOCI FOUND TO MEET STRICT CRITERIA FOR DIFFERENTIAL EXPRESSION IN THE MICROARRAY EXPERIMENT SHOWED CONTRASTING PATTERNS OF EXPRESSION THAT DISTINGUISHED THE TWO GROUPS. DIFFERENTIAL EXPRESSION RELATING TO IMMUNE FUNCTION AND ENERGY EFFICIENCY WERE MOST APPARENT. IN THE TM GROUP, RELATIVE TO THE CONTROL, ALL 49 GENES ASSOCIATED WITH INFLAMMATION WERE DOWNREGULATED, WHILE GENES ASSOCIATED WITH ANTIVIRAL AND ANTIBODY COMPONENTS OF THE DEFENSE RESPONSE WERE UPREGULATED. THE LARGEST EXPRESSION DIFFERENCES WERE SHOWN BY SIX GENES RELATED TO ERYTHROCYTE FUNCTION THAT APPEARED TO REFLECT A CONDITION OF LOWER ENERGY EFFICIENCY IN THE CONTROL GROUP. RESULTS SUPPORTING THESE GENE EXPRESSION DIFFERENCES WERE OBTAINED WITH QPCR-MEASURED EXPRESSION BOTH IN THE WELL-MATCHED MICROARRAY GROUPS AND IN THE LARGER, LESS WELL-MATCHED GROUPS. CONCLUSIONS: THESE FINDINGS ARE CONSISTENT WITH PREDICTIONS BASED ON RESULTS FROM EARLIER RANDOMIZED TRIALS OF MEDITATION AND MAY PROVIDE EVIDENCE FOR STRESS-RELATED MOLECULAR MECHANISMS UNDERLYING REDUCTIONS IN ANXIETY, POST-TRAUMATIC STRESS DISORDER (PTSD), CARDIOVASCULAR DISEASE (CVD), AND OTHER CHRONIC DISORDERS AND DISEASES. 2021 18 6083 34 THE EFFECT OF SMOKING ON DNA METHYLATION OF PERIPHERAL BLOOD MONONUCLEAR CELLS FROM AFRICAN AMERICAN WOMEN. BACKGROUND: REGULAR SMOKING IS ASSOCIATED WITH A WIDE VARIETY OF SYNDROMES WITH PROMINENT INFLAMMATORY COMPONENTS SUCH AS CANCER, OBESITY AND TYPE 2 DIABETES. HEAVY REGULAR SMOKING IS ALSO ASSOCIATED WITH CHANGES IN THE DNA METHYLATION OF PERIPHERAL MONONUCLEAR CELLS. HOWEVER, IN YOUNGER SMOKERS, INFLAMMATORY EPIGENETIC FINDINGS ARE LARGELY ABSENT WHICH SUGGESTS THE INFLAMMATORY RESPONSE(S) TO SMOKING MAY BE DOSE DEPENDENT. TO HELP UNDERSTAND WHETHER PERIPHERAL MONONUCLEAR CELLS HAVE A ROLE IN MEDIATING THESE RESPONSES IN OLDER SMOKERS WITH HIGHER CUMULATIVE SMOKE EXPOSURE, WE EXAMINED GENOME-WIDE DNA METHYLATION IN A GROUP OF WELL CHARACTERIZED ADULT AFRICAN AMERICAN SUBJECTS INFORMATIVE FOR SMOKING, AS WELL AS SERUM C-REACTIVE PROTEIN (CRP) AND INTERLEUKIN-6 RECEPTOR (IL6R) LEVELS. IN ADDITION, COMPLEMENTARY BIOINFORMATIC ANALYSES WERE CONDUCTED TO DELINEATE POSSIBLE PATHWAYS AFFECTED BY LONG-TERM SMOKING. RESULTS: GENOME-WIDE DNA METHYLATION ANALYSIS WITH RESPECT TO SMOKING STATUS YIELDED 910 SIGNIFICANT LOCI AFTER BENJAMINI-HOCHBERG CORRECTION. IN PARTICULAR, TWO LOCI FROM THE AHRR GENE (CG05575921 AND CG23576855) AND ONE LOCUS FROM THE GPR15 GENE (CG19859270) WERE IDENTIFIED AS HIGHLY SIGNIFICANTLY DIFFERENTIALLY METHYLATED BETWEEN SMOKERS AND NON-SMOKERS. THE BIOINFORMATIC ANALYSES SHOWED THAT LONG-TERM CHRONIC SMOKING IS ASSOCIATED WITH ALTERED PROMOTER DNA METHYLATION OF GENES CODING FOR PROTEINS MAPPING TO CRITICAL SUB-NETWORKS MODERATING INFLAMMATION, IMMUNE FUNCTION, AND COAGULATION. CONCLUSIONS: WE CONCLUDE THAT CHRONIC REGULAR SMOKING IS ASSOCIATED WITH CHANGES IN PERIPHERAL MONONUCLEAR CELL METHYLATION SIGNATURE WHICH PERTURB INFLAMMATORY AND IMMUNE FUNCTION PATHWAYS AND MAY CONTRIBUTE TO INCREASED VULNERABILITY FOR COMPLEX ILLNESSES WITH INFLAMMATORY COMPONENTS. 2014 19 1909 33 ENRICHMENT OF GENOMIC PATHWAYS BASED ON DIFFERENTIAL DNA METHYLATION PROFILES ASSOCIATED WITH CHRONIC MUSCULOSKELETAL PAIN IN OLDER ADULTS: AN EXPLORATORY STUDY. OUR STUDY AIMED TO IDENTIFY DIFFERENTIALLY METHYLATED CPGS/REGIONS AND THEIR ENRICHED GENOMIC PATHWAYS ASSOCIATED WITH UNDERLYING CHRONIC MUSCULOSKELETAL PAIN IN OLDER INDIVIDUALS. WE RECRUITED COGNITIVELY HEALTHY OLDER ADULTS WITH (N = 20) AND WITHOUT (N = 9) SELF-REPORTED MUSCULOSKELETAL PAIN AND COLLECTED DNA FROM PERIPHERAL BLOOD THAT WAS ANALYZED USING METHYLATIONEPIC ARRAYS. WE IDENTIFIED 31,739 HYPERMETHYLATED CPG AND 10,811 HYPOMETHYLATED CPG PROBES (PS