1 5748 144 SOCIAL AND PHYSICAL ENVIRONMENTS EARLY IN DEVELOPMENT PREDICT DNA METHYLATION OF INFLAMMATORY GENES IN YOUNG ADULTHOOD. CHRONIC INFLAMMATION CONTRIBUTES TO A WIDE RANGE OF HUMAN DISEASES, AND ENVIRONMENTS IN INFANCY AND CHILDHOOD ARE IMPORTANT DETERMINANTS OF INFLAMMATORY PHENOTYPES. THE UNDERLYING BIOLOGICAL MECHANISMS CONNECTING EARLY ENVIRONMENTS WITH THE REGULATION OF INFLAMMATION IN ADULTHOOD ARE NOT KNOWN, BUT EPIGENETIC PROCESSES ARE PLAUSIBLE CANDIDATES. WE TESTED THE HYPOTHESIS THAT PATTERNS OF DNA METHYLATION (DNAM) IN INFLAMMATORY GENES IN YOUNG ADULTHOOD WOULD BE PREDICTED BY EARLY LIFE NUTRITIONAL, MICROBIAL, AND PSYCHOSOCIAL EXPOSURES PREVIOUSLY ASSOCIATED WITH LEVELS OF INFLAMMATION. DATA COME FROM A POPULATION-BASED LONGITUDINAL BIRTH COHORT STUDY IN METROPOLITAN CEBU, THE PHILIPPINES, AND DNAM WAS CHARACTERIZED IN WHOLE BLOOD SAMPLES FROM 494 PARTICIPANTS (AGE 20-22 Y). ANALYSES FOCUSED ON PROBES IN 114 TARGET GENES INVOLVED IN THE REGULATION OF INFLAMMATION, AND WE IDENTIFIED 10 SITES ACROSS NINE GENES WHERE THE LEVEL OF DNAM WAS SIGNIFICANTLY PREDICTED BY THE FOLLOWING VARIABLES: HOUSEHOLD SOCIOECONOMIC STATUS IN CHILDHOOD, EXTENDED ABSENCE OF A PARENT IN CHILDHOOD, EXPOSURE TO ANIMAL FECES IN INFANCY, BIRTH IN THE DRY SEASON, OR DURATION OF EXCLUSIVE BREASTFEEDING. TO EVALUATE THE BIOLOGICAL SIGNIFICANCE OF THESE SITES, WE TESTED FOR ASSOCIATIONS WITH A PANEL OF INFLAMMATORY BIOMARKERS MEASURED IN PLASMA OBTAINED AT THE SAME AGE AS DNAM ASSESSMENT. THREE SITES PREDICTED ELEVATED INFLAMMATION, AND ONE SITE PREDICTED LOWER INFLAMMATION, CONSISTENT WITH THE INTERPRETATION THAT LEVELS OF DNAM AT THESE SITES ARE FUNCTIONALLY RELEVANT. THIS PATTERN OF RESULTS POINTS TOWARD DNAM AS A POTENTIALLY IMPORTANT BIOLOGICAL MECHANISM THROUGH WHICH DEVELOPMENTAL ENVIRONMENTS SHAPE INFLAMMATORY PHENOTYPES ACROSS THE LIFE COURSE. 2017 2 2677 35 EVALUATING THE CHALLENGES AND REPRODUCIBILITY OF STUDIES INVESTIGATING DNA METHYLATION SIGNATURES OF PSYCHOLOGICAL STRESS. PSYCHOLOGICAL STRESS CAN INCREASE THE RISK OF A WIDE RANGE OF NEGATIVE HEALTH OUTCOMES. STUDIES HAVE BEEN COMPLETED TO DETERMINE IF DNA METHYLATION CHANGES OCCUR IN THE HUMAN BRAIN BECAUSE OF STRESS AND ARE ASSOCIATED WITH LONG-TERM EFFECTS AND DISEASE, BUT RESULTS HAVE BEEN INCONSISTENT. HUMAN CANDIDATE GENE STUDIES (150) AND EPIGENOME-WIDE ASSOCIATION STUDIES (67) WERE SYSTEMATICALLY EVALUATED TO ASSESS HOW DNA METHYLATION IS IMPACTED BY STRESS DURING THE PRENATAL PERIOD, EARLY CHILDHOOD AND ADULTHOOD. THE ASSOCIATION BETWEEN DNA METHYLATION OF NR3C1 EXON 1F AND CHILD MALTREATMENT AND EARLY LIFE ADVERSITY WAS WELL DEMONSTRATED, BUT OTHER GENES DID NOT EXHIBIT A CLEAR ASSOCIATION. THE REPRODUCIBILITY OF INDIVIDUAL CPG SITES IN EPIGENOME-WIDE ASSOCIATION STUDIES WAS ALSO POOR. HOWEVER, BIOLOGICAL PATHWAYS, INCLUDING STRESS RESPONSE, BRAIN DEVELOPMENT AND IMMUNITY, HAVE BEEN CONSISTENTLY IDENTIFIED ACROSS DIFFERENT STRESSORS THROUGHOUT THE LIFE SPAN. FUTURE STUDIES WOULD BENEFIT FROM THE INCREASED SAMPLE SIZE, LONGITUDINAL DESIGN, STANDARDIZED METHODOLOGY, OPTIMAL QUALITY CONTROL, AND IMPROVED STATISTICAL PROCEDURES. 2022 3 1599 45 DNA METHYLATION SIGNATURE OF CHILDHOOD CHRONIC PHYSICAL AGGRESSION IN T CELLS OF BOTH MEN AND WOMEN. BACKGROUND: HIGH FREQUENCY OF PHYSICAL AGGRESSION IS THE CENTRAL FEATURE OF SEVERE CONDUCT DISORDER AND IS ASSOCIATED WITH A WIDE RANGE OF SOCIAL, MENTAL AND PHYSICAL HEALTH PROBLEMS. WE HAVE PREVIOUSLY TESTED THE HYPOTHESIS THAT DIFFERENTIAL DNA METHYLATION SIGNATURES IN PERIPHERAL T CELLS ARE ASSOCIATED WITH A CHRONIC AGGRESSION TRAJECTORY IN MALES. DESPITE THE FACT THAT SEX DIFFERENCES APPEAR TO PLAY A PIVOTAL ROLE IN DETERMINING THE DEVELOPMENT, MAGNITUDE AND FREQUENCY OF AGGRESSION, MOST OF PREVIOUS STUDIES FOCUSED ON MALES, SO LITTLE IS KNOWN ABOUT FEMALE CHRONIC PHYSICAL AGGRESSION. WE THEREFORE TESTED HERE WHETHER OR NOT THERE IS A SIGNATURE OF PHYSICAL AGGRESSION IN FEMALE DNA METHYLATION AND, IF THERE IS, HOW IT RELATES TO THE SIGNATURE OBSERVED IN MALES. METHODOLOGY/PRINCIPAL FINDINGS: METHYLATION PROFILES WERE CREATED USING THE METHOD OF METHYLATED DNA IMMUNOPRECIPITATION (MEDIP) FOLLOWED BY MICROARRAY HYBRIDIZATION AND STATISTICAL AND BIOINFORMATIC ANALYSES ON T CELL DNA OBTAINED FROM ADULT WOMEN WHO WERE FOUND TO BE ON A CHRONIC PHYSICAL AGGRESSION TRAJECTORY (CPA) BETWEEN 6 AND 12 YEARS OF AGE COMPARED TO WOMEN WHO FOLLOWED A NORMAL PHYSICAL AGGRESSION TRAJECTORY. WE CONFIRMED THE EXISTENCE OF A WELL-DEFINED, GENOME-WIDE SIGNATURE OF DNA METHYLATION ASSOCIATED WITH CHRONIC PHYSICAL AGGRESSION IN THE PERIPHERAL T CELLS OF ADULT FEMALES THAT INCLUDES MANY OF THE GENES SIMILARLY ASSOCIATED WITH PHYSICAL AGGRESSION IN THE SAME CELL TYPES OF ADULT MALES. CONCLUSIONS: THIS STUDY IN A SMALL NUMBER OF WOMEN PRESENTS PRELIMINARY EVIDENCE FOR A GENOME-WIDE VARIATION IN PROMOTER DNA METHYLATION THAT ASSOCIATES WITH CPA IN WOMEN THAT WARRANT LARGER STUDIES FOR FURTHER VERIFICATION. A SIGNIFICANT PROPORTION OF THESE ASSOCIATIONS WERE PREVIOUSLY OBSERVED IN MEN WITH CPA SUPPORTING THE HYPOTHESIS THAT THE EPIGENETIC SIGNATURE OF EARLY LIFE AGGRESSION IN FEMALES IS COMPOSED OF A COMPONENT SPECIFIC TO FEMALES AND ANOTHER COMMON TO BOTH MALES AND FEMALES. 2014 4 4085 46 MATERNAL OBESITY AND GESTATIONAL DIABETES REPROGRAM THE METHYLOME OF OFFSPRING BEYOND BIRTH BY INDUCING EPIGENETIC SIGNATURES IN METABOLIC AND DEVELOPMENTAL PATHWAYS. BACKGROUND: OBESITY IS A NEGATIVE CHRONIC METABOLIC HEALTH CONDITION THAT REPRESENTS AN ADDITIONAL RISK FOR THE DEVELOPMENT OF MULTIPLE PATHOLOGIES. EPIDEMIOLOGICAL STUDIES HAVE SHOWN HOW MATERNAL OBESITY OR GESTATIONAL DIABETES MELLITUS DURING PREGNANCY CONSTITUTE SERIOUS RISK FACTORS IN RELATION TO THE APPEARANCE OF CARDIOMETABOLIC DISEASES IN THE OFFSPRING. FURTHERMORE, EPIGENETIC REMODELLING MAY HELP EXPLAIN THE MOLECULAR MECHANISMS THAT UNDERLIE THESE EPIDEMIOLOGICAL FINDINGS. THUS, IN THIS STUDY WE EXPLORED THE DNA METHYLATION LANDSCAPE OF CHILDREN BORN TO MOTHERS WITH OBESITY AND GESTATIONAL DIABETES DURING THEIR FIRST YEAR OF LIFE. METHODS: WE USED ILLUMINA INFINIUM METHYLATIONEPIC BEADCHIP ARRAYS TO PROFILE MORE THAN 770,000 GENOME-WIDE CPG SITES IN BLOOD SAMPLES FROM A PAEDIATRIC LONGITUDINAL COHORT CONSISTING OF 26 CHILDREN BORN TO MOTHERS WHO SUFFERED FROM OBESITY OR OBESITY WITH GESTATIONAL DIABETES MELLITUS DURING PREGNANCY AND 13 HEALTHY CONTROLS (MEASUREMENTS TAKEN AT 0, 6 AND 12 MONTH; TOTAL N = 90). WE CARRIED OUT CROSS-SECTIONAL AND LONGITUDINAL ANALYSES TO DERIVE DNA METHYLATION ALTERATIONS ASSOCIATED WITH DEVELOPMENTAL AND PATHOLOGY-RELATED EPIGENOMICS. RESULTS: WE IDENTIFIED ABUNDANT DNA METHYLATION CHANGES DURING CHILD DEVELOPMENT FROM BIRTH TO 6 MONTHS AND, TO A LESSER EXTENT, UP TO 12 MONTHS OF AGE. USING CROSS-SECTIONAL ANALYSES, WE DISCOVERED DNA METHYLATION BIOMARKERS MAINTAINED ACROSS THE FIRST YEAR OF LIFE THAT COULD DISCRIMINATE CHILDREN BORN TO MOTHERS WHO SUFFERED FROM OBESITY OR OBESITY WITH GESTATIONAL DIABETES. IMPORTANTLY, ENRICHMENT ANALYSES SUGGESTED THAT THESE ALTERATIONS CONSTITUTE EPIGENETIC SIGNATURES THAT AFFECT GENES AND PATHWAYS INVOLVED IN THE METABOLISM OF FATTY ACIDS, POSTNATAL DEVELOPMENTAL PROCESSES AND MITOCHONDRIAL BIOENERGETICS, SUCH AS CPT1B, SLC38A4, SLC35F3 AND FN3K. FINALLY, WE OBSERVED EVIDENCE OF AN INTERACTION BETWEEN DEVELOPMENTAL DNA METHYLATION CHANGES AND MATERNAL METABOLIC CONDITION ALTERATIONS. CONCLUSIONS: OUR OBSERVATIONS HIGHLIGHT THE FIRST SIX MONTHS OF DEVELOPMENT AS BEING THE MOST CRUCIAL FOR EPIGENETIC REMODELLING. FURTHERMORE, OUR RESULTS SUPPORT THE EXISTENCE OF SYSTEMIC INTRAUTERINE FOETAL PROGRAMMING LINKED TO OBESITY AND GESTATIONAL DIABETES THAT AFFECTS THE CHILDHOOD METHYLOME BEYOND BIRTH, WHICH INVOLVES ALTERATIONS RELATED TO METABOLIC PATHWAYS, AND WHICH MAY INTERACT WITH ORDINARY POSTNATAL DEVELOPMENT PROGRAMMES. 2023 5 1503 36 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 6 1439 41 DIFFERENTIAL PLACENTAL CPG METHYLATION IS ASSOCIATED WITH CHRONIC LUNG DISEASE OF PREMATURITY. BACKGROUND: CHRONIC LUNG DISEASE (CLD) IS THE MOST COMMON PULMONARY MORBIDITY IN EXTREMELY PRETERM INFANTS. IT IS UNCLEAR TO WHAT EXTENT PRENATAL EXPOSURES INFLUENCE THE RISK OF CLD. EPIGENETIC VARIATION IN PLACENTA DNA METHYLATION MAY BE ASSOCIATED WITH DIFFERENTIAL RISK OF CLD, AND THESE ASSOCIATIONS MAY BE DEPENDENT UPON SEX. METHODS: DATA WERE OBTAINED FROM A MULTI-CENTER COHORT OF INFANTS BORN EXTREMELY PRETERM (<28 WEEKS' GESTATION) AND AN EPIGENOME-WIDE APPROACH WAS USED TO IDENTIFY ASSOCIATIONS BETWEEN PLACENTAL DNA METHYLATION AND CLD (N = 423). ASSOCIATIONS WERE EVALUATED USING ROBUST LINEAR REGRESSION ADJUSTING FOR COVARIATES, WITH A FALSE DISCOVERY RATE OF 0.05. ANALYSES STRATIFIED BY SEX WERE USED TO ASSESS DIFFERENCES IN METHYLATION-CLD ASSOCIATIONS. RESULTS: CLD WAS ASSOCIATED WITH DIFFERENTIAL METHYLATION AT 49 CPG SITES REPRESENTING 46 GENES IN THE PLACENTA. CLD WAS ASSOCIATED WITH DIFFERENTIAL METHYLATION OF PROBES WITHIN GENES RELATED TO PATHWAYS INVOLVED IN FETAL LUNG DEVELOPMENT, SUCH AS P53 SIGNALING AND MYO-INOSITOL BIOSYNTHESIS. ASSOCIATIONS BETWEEN CPG METHYLATION AND CLD DIFFERED BY SEX. CONCLUSIONS: DIFFERENTIAL PLACENTAL METHYLATION WITHIN GENES WITH KEY ROLES IN FETAL LUNG DEVELOPMENT MAY REFLECT COMPLEX CELL SIGNALING BETWEEN THE PLACENTA AND FETUS WHICH MEDIATE CLD RISK. THESE PATHWAYS APPEAR TO BE DISTINCT BASED ON FETAL SEX. IMPACT: IN EXTREMELY PRETERM INFANTS, DIFFERENTIAL METHYLATION OF CPG SITES WITHIN PLACENTAL GENES INVOLVED IN PATHWAYS RELATED TO CELL SIGNALING, OXIDATIVE STRESS, AND TROPHOBLAST INVASION IS ASSOCIATED WITH CHRONIC LUNG DISEASE OF PREMATURITY. DNA METHYLATION PATTERNS ASSOCIATED WITH CHRONIC LUNG DISEASE WERE DISTINCTLY BASED ON FETAL SEX, SUGGESTING A POTENTIAL MECHANISM UNDERLYING DIMORPHIC PHENOTYPES. MECHANISMS RELATED TO FETAL HYPOXIA AND PLACENTAL MYO-INOSITOL SIGNALING MAY PLAY A ROLE IN FETAL LUNG PROGRAMMING AND THE DEVELOPMENTAL ORIGINS OF CHRONIC LUNG DISEASE. CONTINUED RESEARCH OF THE RELATIONSHIP BETWEEN THE PLACENTAL EPIGENOME AND CHRONIC LUNG DISEASE COULD INFORM EFFORTS TO AMELIORATE OR PREVENT THIS CONDITION. 2022 7 1516 37 DNA METHYLATION AS A BIOMARKER OF AGING IN EPIDEMIOLOGIC STUDIES. CANCER IS LARGELY AN AGING DISEASE. ACCELERATED BIOLOGICAL AGING MAY BE THE STRONGEST PREDICTOR OF CANCER AND OTHER CHRONIC DISEASE RISKS. IN THE ABSENCE OF RELIABLE AND QUANTIFIABLE BIOMARKERS OF AGING TO DATE, IT HAS LONG BEEN OBSERVED THAT TUMORIGENESIS SHARES DISTINCT EPIGENETIC ALTERATIONS WITH THE AGING PROCESS. RECENTLY, EPIGENETIC AGE ESTIMATES HAVE BEEN DEVELOPED BASED ON THE AVAILABILITY OF GENOME-WIDE DNA METHYLATION PROFILES, BY APPLYING IN THE PREDICTION FORMULA THE METHYLATION LEVEL AT A SUBSET OF HIGHLY PREDICTIVE METHYLATION SITES, CALLED EPIGENETIC CLOCK. THESE DNA METHYLATION AGE ESTIMATES HAVE PRODUCED REMARKABLY STRONG CORRELATIONS WITH CHRONOLOGICAL AGE, WITH A SMALL DEVIATION AND HIGH REPRODUCIBILITY ACROSS DIFFERENT AGE GROUPS AND STUDY POPULATIONS. MOREOVER, AN INCREASING NUMBER OF EPIDEMIOLOGIC STUDIES HAVE DEMONSTRATED AN INDEPENDENT ASSOCIATION OF DNA METHYLATION AGE OR THE EXTENT OF ACCELERATION WITH MORTALITY AND VARIOUS AGING-RELATED CONDITIONS, EVEN AFTER ACCOUNTING FOR DIFFERENCES IN CHRONOLOGICAL AGE AND OTHER RISK FACTORS. ALTHOUGH EPIGENETIC PROFILES ARE KNOWN TO BE TISSUE-SPECIFIC, BOTH TARGET TISSUE- AND MULTIPLE TISSUE-DERIVED ESTIMATES APPEAR TO PERFORM WELL TO CAPTURE WHAT IS THOUGHT TO BE THE CUMULATIVE EPIGENETIC DRIFT THAT REPRESENTS A MULTIFACTORIAL DEGENERATIVE PROCESS ACROSS TISSUES AND ORGANISMS. FURTHER REFINEMENT OF THE EPIGENETIC AGE ESTIMATES IS ANTICIPATED OVER TIME TO ACCOMMODATE A BETTER TECHNOLOGICAL COVERAGE OF THE METHYLOME AND A BETTER UNDERSTANDING OF THE BIOLOGY UNDERLYING PREDICTIVE REGIONS. EPIDEMIOLOGIC PRINCIPLES WILL REMAIN CRITICAL FOR THE EVALUATION OF RESEARCH FINDINGS INVOLVING, FOR EXAMPLE, DIFFERENT STUDY POPULATIONS, DESIGN, FOLLOW-UP TIME, AND QUALITY OF COVARIATE DATA. OVERALL, THE EPIGENETIC AGE ESTIMATES ARE AN EXCITING DEVELOPMENT WITH USEFUL IMPLICATIONS FOR BIOMEDICAL RESEARCH OF HEALTHY AGING AND DISEASE PREVENTION AND CONTROL. 2018 8 2075 42 EPIGENETIC DIFFERENCES IN INFLAMMATION GENES OF MONOZYGOTIC TWINS ARE RELATED TO PARENT-CHILD EMOTIONAL AVAILABILITY AND HEALTH. THE INFLAMMATORY RESPONSE IS AN IMMUNE DEFENSE ENGAGED IMMEDIATELY AFTER INJURY OR INFECTION. CHRONIC INFLAMMATION CAN BE DELETERIOUS FOR VARIOUS HEALTH OUTCOMES AND IS CHARACTERIZED BY HIGH LEVELS OF PRO-INFLAMMATORY MARKERS SUCH AS C-REACTIVE PROTEIN (CRP), INTERLEUKIN 6 (IL-6), AND TUMOR NECROSIS FACTOR ALPHA (TNF-ALPHA). A LARGE BODY OF RESEARCH DEMONSTRATES THESE INFLAMMATORY MARKERS ARE RESPONSIVE TO STRESS AND QUALITY OF SOCIAL RELATIONSHIPS THROUGHOUT THE LIFESPAN. FOR EXAMPLE, THE QUALITY OF THE EARLY PARENTAL BOND PREDICTS VARIOUS HEALTH OUTCOMES AND MAY BE DRIVEN BY CHANGES IN IMMUNE FUNCTION. EPIGENETIC PROCESSES, SUCH AS DNA METHYLATION, MAY BE ONE MECHANISM BY WHICH EARLY SOCIAL EXPERIENCES SHAPE IMMUNE FUNCTIONING. THE PRESENT STUDY USED A MONOZYGOTIC TWIN DIFFERENCE DESIGN TO ASSESS IF MOTHER-REPORTED EMOTIONAL AVAILABILITY AT 1 YEAR AND 2.5 YEARS PREDICTED IMMUNE GENE METHYLATION AT 8 YEARS OF AGE. FURTHER, WE ASSESSED IF INFLAMMATION GENE METHYLATION WAS RELATED TO GENERAL HEALTH PROBLEMS (E.G. INFECTIONS, ALLERGIES, ETC.). WE FOUND THAT MOTHER-REPORTED EMOTIONAL AVAILABILITY AT 1 YEAR, BUT NOT 2.5 YEARS, WAS RELATED TO METHYLATION OF VARIOUS IMMUNE GENES IN MONOZYGOTIC TWINS. FURTHERMORE, TWIN PAIRS DISCORDANT IN HEALTH PROBLEMS HAVE MORE DIFFERENCE IN IMMUNE GENE METHYLATION COMPARED TO TWIN PAIRS CONCORDANT FOR HEALTH PROBLEMS, SUGGESTING THAT METHYLATION OF IMMUNE GENES MAY HAVE FUNCTIONAL CONSEQUENCES FOR GENERAL HEALTH. THESE RESULTS SUGGEST THAT THE EMOTIONAL COMPONENT OF ATTACHMENT QUALITY DURING INFANCY CONTRIBUTES TO IMMUNE EPIGENETIC PROFILES IN CHILDHOOD, WHICH MAY INFLUENCE GENERAL HEALTH. 2020 9 1583 34 DNA METHYLATION PROFILES OF BLOOD CELLS ARE DISTINCT BETWEEN EARLY-ONSET OBESE AND CONTROL INDIVIDUALS. OBESITY IS A HIGHLY PREVALENT, CHRONIC DISORDER THAT HAS BEEN INCREASING IN INCIDENCE IN YOUNG PATIENTS. BOTH EPIGENETIC AND GENETIC ABERRATIONS MAY PLAY A ROLE IN THE PATHOGENESIS OF OBESITY. THEREFORE, IN-DEPTH EPIGENOMIC AND GENOMIC ANALYSES WILL ADVANCE OUR UNDERSTANDING OF THE DETAILED MOLECULAR MECHANISMS UNDERLYING OBESITY AND AID IN THE SELECTION OF POTENTIAL BIOMARKERS FOR OBESITY IN YOUTH. HERE, WE PERFORMED MICROARRAY-BASED DNA METHYLATION AND GENE EXPRESSION PROFILING OF PERIPHERAL WHITE BLOOD CELLS OBTAINED FROM SIX YOUNG, OBESE INDIVIDUALS AND SIX HEALTHY CONTROLS. WE OBSERVED THAT THE HIERARCHICAL CLUSTERING OF DNA METHYLATION, BUT NOT GENE EXPRESSION, CLEARLY SEGREGATES THE OBESE INDIVIDUALS FROM THE CONTROLS, SUGGESTING THAT THE METABOLIC DISTURBANCE THAT OCCURS AS A RESULT OF OBESITY AT A YOUNG AGE MAY AFFECT THE DNA METHYLATION OF PERIPHERAL BLOOD CELLS WITHOUT ACCOMPANYING TRANSCRIPTIONAL CHANGES. TO EXAMINE THE GENOME-WIDE DIFFERENCES IN THE DNA METHYLATION PROFILES OF YOUNG OBESE AND CONTROL INDIVIDUALS, WE IDENTIFIED DIFFERENTIALLY METHYLATED CPG SITES AND INVESTIGATED THEIR GENOMIC AND EPIGENOMIC CONTEXTS. THE ABERRANT DNA METHYLATION PATTERNS IN OBESE INDIVIDUALS CAN BE SUMMARIZED AS RELATIVE GAINS AND LOSSES OF DNA METHYLATION IN GENE PROMOTERS AND GENE BODIES, RESPECTIVELY. WE ALSO OBSERVED THAT THE CPG ISLANDS OF OBESE INDIVIDUALS ARE MORE SUSCEPTIBLE TO DNA METHYLATION COMPARED TO CONTROLS. OUR PILOT STUDY SUGGESTS THAT THE GENOME-WIDE ABERRANT DNA METHYLATION PATTERNS OF OBESE INDIVIDUALS MAY ADVANCE NOT ONLY OUR UNDERSTANDING OF THE EPIGENOMIC PATHOGENESIS BUT ALSO EARLY SCREENING OF OBESITY IN YOUTH. 2017 10 287 38 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 11 3652 40 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 12 247 36 ADULTHOOD ASTHMA AS A CONSEQUENCE OF CHILDHOOD ADVERSITY: A SYSTEMATIC REVIEW OF EPIGENETICALLY AFFECTED GENES. THERE IS AN ACCUMULATING DATA THAT SHOWS RELATION BETWEEN CHILDHOOD ADVERSITY AND VULNERABILITY TO CHRONIC DISEASES AS WELL AS EPIGENETIC INFLUENCES THAT IN TURN GIVE RISE TO THESE DISEASES. ASTHMA IS ONE OF THE CHRONIC DISEASES THAT IS INFLUENCED FROM GENETIC REGULATION OF THE INFLAMMATORY BIOMOLECULES AND THEREFORE THE HYPOTHESIS IN THIS RESEARCH WAS CHILDHOOD ADVERSITY MIGHT HAVE CAUSED EPIGENETIC DIFFERENTIATION IN THE ASTHMA-RELATED GENES IN THE POPULATION WHO HAD CHILDHOOD TRAUMA. TO TEST THIS HYPOTHESIS, THE LITERATURE WAS SYSTEMATICALLY REVIEWED TO EXTRACT EPIGENETICALLY MODIFIED GENE DATA OF THE ADULTS WHO HAD CHILDHOOD ADVERSITY, AND AFFECTED GENES WERE FURTHER EVALUATED FOR THEIR ASSOCIATION WITH ASTHMA. PRISMA GUIDELINES WERE ADOPTED AND PUBMED AND GOOGLE SCHOLAR WERE INCLUDED IN THE SEARCHED DATABASES, TO EVALUATE EPIGENETIC MODIFICATIONS IN ASTHMA-RELATED GENES OF PHYSICALLY, EMOTIONALLY OR SEXUALLY ABUSED CHILDREN. AFTER RETRIEVING A TOTAL OF 5245 ARTICLES, 36 OF THEM WERE INCLUDED IN THE STUDY. SEVERAL GENES AND PATHWAYS THAT MAY CONTRIBUTE TO PATHOGENESIS OF ASTHMA DEVELOPMENT, INCREASED INFLAMMATION, OR RESPONSE TO ASTHMA TREATMENT WERE FOUND EPIGENETICALLY AFFECTED BY CHILDHOOD TRAUMAS. CHILDHOOD ADVERSITY, CAUSING EPIGENETIC CHANGES IN DNA, MAY LEAD TO ASTHMA DEVELOPMENT OR INFLUENCE THE COURSE OF THE DISEASE AND THEREFORE SHOULD BE TAKEN INTO ACCOUNT FOR THE PROLONGED HEALTH CONSEQUENCES. 2022 13 2047 35 EPIGENETIC CLOCKS MAY COME OUT OF RHYTHM-IMPLICATIONS FOR THE ESTIMATION OF CHRONOLOGICAL AGE IN FORENSIC CASEWORK. THERE IS A GROWING PERCEPTION THAT DNA METHYLATION MAY BE INFLUENCED BY EXOGENOUS AND ENDOGENOUS PARAMETERS. KNOWLEDGE OF THESE FACTORS IS OF GREAT RELEVANCE FOR THE INTERPRETATION OF DNA-METHYLATION DATA FOR THE ESTIMATION OF CHRONOLOGICAL AGE IN FORENSIC CASEWORK. WE PERFORMED A LITERATURE REVIEW TO IDENTIFY PARAMETERS, WHICH MIGHT BE OF RELEVANCE FOR THE PREDICTION OF CHRONOLOGICAL AGE BASED ON DNA METHYLATION. THE QUALITY OF AGE PREDICTIONS MIGHT PARTICULARLY BE INFLUENCED BY LIFETIME ADVERSITIES (CHRONIC STRESS, TRAUMA/POST-TRAUMATIC STRESS DISORDER (PTSD), VIOLENCE, LOW SOCIOECONOMIC STATUS/EDUCATION), CANCER, OBESITY AND RELATED DISEASES, INFECTIOUS DISEASES (ESPECIALLY HIV AND CYTOMEGALOVIRUS (CMV) INFECTIONS), SEX, ETHNICITY AND EXPOSURE TO TOXINS (ALCOHOL, SMOKING, AIR POLLUTION, PESTICIDES). SUCH FACTORS MAY ALTER THE DNA METHYLATION PATTERN AND MAY EXPLAIN THE PARTLY HIGH DEVIATIONS BETWEEN EPIGENETIC AGE AND CHRONOLOGICAL AGE IN SINGLE CASES (DESPITE OF LOW MEAN ABSOLUTE DEVIATIONS) THAT CAN ALSO BE OBSERVED WITH "EPIGENETIC CLOCKS" COMPRISING A HIGH NUMBER OF CPG SITES. SO FAR, ONLY FEW PUBLICATIONS DEALING WITH FORENSIC AGE ESTIMATION ADDRESS THESE CONFOUNDING FACTORS. FUTURE RESEARCH SHOULD FOCUS ON THE IDENTIFICATION OF FURTHER RELEVANT CONFOUNDING FACTORS AND THE DEVELOPMENT OF MODELS THAT ARE "ROBUST" AGAINST THE INFLUENCE OF SUCH BIOLOGICAL FACTORS BY SYSTEMATIC INVESTIGATIONS UNDER TARGETED INCLUSION OF DIVERSE AND DEFINED COHORTS. 2020 14 1014 37 CIGARETTE SMOKING AND DNA METHYLATION. DNA METHYLATION IS THE MOST STUDIED EPIGENETIC MODIFICATION, CAPABLE OF CONTROLLING GENE EXPRESSION IN THE CONTEXTS OF NORMAL TRAITS OR DISEASES. IT IS HIGHLY DYNAMIC DURING EARLY EMBRYOGENESIS AND REMAINS RELATIVELY STABLE THROUGHOUT LIFE, AND SUCH PATTERNS ARE INTRICATELY RELATED TO HUMAN DEVELOPMENT. DNA METHYLATION IS A QUANTITATIVE TRAIT DETERMINED BY A COMPLEX INTERPLAY OF GENETIC AND ENVIRONMENTAL FACTORS. GENETIC VARIANTS AT A SPECIFIC LOCUS CAN INFLUENCE BOTH REGIONAL AND DISTANT DNA METHYLATION. THE ENVIRONMENT CAN HAVE VARYING EFFECTS ON DNA METHYLATION DEPENDING ON WHEN THE EXPOSURE OCCURS, SUCH AS DURING PRENATAL LIFE OR DURING ADULTHOOD. IN PARTICULAR, CIGARETTE SMOKING IN THE CONTEXT OF BOTH CURRENT SMOKING AND PRENATAL EXPOSURE IS A STRONG MODIFIER OF DNA METHYLATION. EPIGENOME-WIDE ASSOCIATION STUDIES HAVE UNCOVERED CANDIDATE GENES ASSOCIATED WITH CIGARETTE SMOKING THAT HAVE BIOLOGICALLY RELEVANT FUNCTIONS IN THE ETIOLOGY OF SMOKING-RELATED DISEASES. AS SUCH, DNA METHYLATION IS A POTENTIAL MECHANISTIC LINK BETWEEN CURRENT SMOKING AND CANCER, AS WELL AS PRENATAL CIGARETTE-SMOKE EXPOSURE AND THE DEVELOPMENT OF ADULT CHRONIC DISEASES. 2013 15 6065 41 THE DEVELOPMENTAL ORIGINS OF CHRONIC PHYSICAL AGGRESSION: BIOLOGICAL PATHWAYS TRIGGERED BY EARLY LIFE ADVERSITY. LONGITUDINAL EPIDEMIOLOGICAL STUDIES WITH BIRTH COHORTS HAVE SHOWN THAT PHYSICAL AGGRESSION IN HUMANS DOES NOT APPEAR SUDDENLY IN ADOLESCENCE AS COMMONLY THOUGHT. IN FACT, PHYSICALLY AGGRESSIVE BEHAVIOUR IS OBSERVED AS EARLY AS 12 MONTHS AFTER BIRTH, ITS FREQUENCY PEAKS AROUND 2-4 YEARS OF AGE AND DECREASES IN FREQUENCY UNTIL EARLY ADULTHOOD. HOWEVER, A MINORITY OF CHILDREN (3-7%) MAINTAIN A HIGH FREQUENCY OF PHYSICAL AGGRESSION FROM CHILDHOOD TO ADOLESCENCE AND DEVELOP SERIOUS SOCIAL ADJUSTMENT PROBLEMS DURING ADULTHOOD. GENETIC FACTORS AND EARLY SOCIAL EXPERIENCES, AS WELL AS THEIR INTERACTION, HAVE BEEN SHOWN TO PLAY AN IMPORTANT ROLE IN THE DEVELOPMENT OF CHRONIC AGGRESSIVE BEHAVIOUR. HOWEVER, THE BIOLOGICAL MECHANISMS UNDERLYING THESE ASSOCIATIONS ARE JUST BEGINNING TO BE UNCOVERED. RECENT EVIDENCE SUGGESTS THAT EPIGENETIC MECHANISMS ARE RESPONSIVE TO ADVERSE ENVIRONMENTS AND COULD BE INVOLVED IN THE DEVELOPMENT OF CHRONIC AGGRESSION. USING BOTH GENE CANDIDATE AND GENOMIC APPROACHES, RECENT STUDIES HAVE IDENTIFIED EPIGENETIC MARKS, SUCH AS DNA METHYLATION ALTERATIONS IN GENES INVOLVED IN THE STRESS RESPONSE AND THE SEROTONIN AND IMMUNE SYSTEMS TO BE PARTLY RESPONSIBLE FOR THE LONG-LASTING EFFECTS OF EARLY ADVERSITY. FURTHER LONGITUDINAL STUDIES WITH BIOLOGICAL, ENVIRONMENTAL AND BEHAVIOURAL ASSESSMENTS FROM BIRTH ONWARDS ARE NEEDED TO ELUCIDATE THE SEQUENCE OF EVENTS THAT LEADS TO THESE LONG-LASTING EPIGENETIC MARKS ASSOCIATED WITH EARLY ADVERSITY AND AGGRESSION. 2015 16 2922 43 GENE-SPECIFIC DNA METHYLATION ASSOCIATION WITH SERUM LEVELS OF C-REACTIVE PROTEIN IN AFRICAN AMERICANS. A MORE THOROUGH UNDERSTANDING OF THE DIFFERENCES IN DNA METHYLATION (DNAM) PROFILES IN POPULATIONS MAY HOLD PROMISE FOR IDENTIFYING MOLECULAR MECHANISMS THROUGH WHICH GENETIC AND ENVIRONMENTAL FACTORS JOINTLY CONTRIBUTE TO HUMAN DISEASES. INFLAMMATION IS A KEY MOLECULAR MECHANISM UNDERLYING SEVERAL CHRONIC DISEASES INCLUDING CARDIOVASCULAR DISEASE, AND IT AFFECTS DNAM PROFILE ON BOTH GLOBAL AND LOCUS-SPECIFIC LEVELS. TO UNDERSTAND THE IMPACT OF INFLAMMATION ON THE DNAM OF THE HUMAN GENOME, WE INVESTIGATED DNAM PROFILES OF PERIPHERAL BLOOD LEUKOCYTES FROM 966 AFRICAN AMERICAN PARTICIPANTS IN THE GENETIC EPIDEMIOLOGY NETWORK OF ARTERIOPATHY (GENOA) STUDY. BY TESTING THE ASSOCIATION OF DNAM SITES ON CPG ISLANDS OF OVER 14,000 GENES WITH C-REACTIVE PROTEIN (CRP), AN INFLAMMATORY BIOMARKER OF CARDIOVASCULAR DISEASE, WE IDENTIFIED 257 DNAM SITES IN 240 GENES SIGNIFICANTLY ASSOCIATED WITH SERUM LEVELS OF CRP ADJUSTED FOR AGE, SEX, BODY MASS INDEX AND SMOKING STATUS, AND CORRECTED FOR MULTIPLE TESTING. OF THE SIGNIFICANTLY ASSOCIATED DNAM SITES, 80.5% WERE HYPOMETHYLATED WITH HIGHER CRP LEVELS. THE MOST SIGNIFICANT GENE ONTOLOGY TERMS ENRICHED IN THE GENES ASSOCIATED WITH THE CRP LEVELS WERE IMMUNE SYSTEM PROCESS, IMMUNE RESPONSE, DEFENSE RESPONSE, RESPONSE TO STIMULUS, AND RESPONSE TO STRESS, WHICH ARE ALL LINKED TO THE FUNCTIONS OF LEUKOCYTES. WHILE THE CRP-ASSOCIATED DNAM MAY BE CELL-TYPE SPECIFIC, UNDERSTANDING THE DNAM ASSOCIATION WITH CRP IN PERIPHERAL BLOOD LEUKOCYTES OF MULTI-ETHNIC POPULATIONS CAN ASSIST IN UNVEILING THE MOLECULAR MECHANISM OF HOW THE PROCESS OF INFLAMMATION AFFECTS THE RISKS OF DEVELOPING COMMON DISEASE THROUGH EPIGENETIC MODIFICATIONS. 2013 17 6311 34 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 18 6790 31 [DNA METHYLATION ANALYSIS IN ENVIRONMENTAL AND OCCUPATIONAL CANCER RESEARCH]. THE PRESENT PAPER REVIEWS RECENT LABORATORY METHODS AND EXPERIMENTAL EVIDENCE CONCERNING EPIGENETIC BIOMARKERS INVOLVED IN CARCINOGENESIS MECHANISMS. WE INTRODUCE DNA METHYLATION AND ITS ROLE IN GENE EXPRESSION CONTROL. DNA METHYLATION ANALYSIS MAY ALLOW TO IDENTIFY EARLY CHANGES LEADING TO CANCER AND OTHER CHRONIC DISEASES. WE DESCRIBE HERE STRATEGIES FOR LABORATORY ANALYSES AND THEIR POSSIBLE APPLICATIONS. WE EXAMINE RESULTS FROM RECENT EXPERIMENTAL STUDIES SUGGESTING THAT THE EFFECTS OF CERTAIN OCCUPATIONAL AGENTS ARE MEDIATED BY ALTERATIONS IN DNA METHYLATION. PLANNING AND CONDUCTING INVESTIGATIONS ON EXPOSED HUMAN SUBJECTS WILL ALLOW TO VERIFY WHETHER DNA METHYLATION CHANGES IDENTIFIED IN ANIMAL AND IN-VITRO STUDIES MAY BE USED AS EARLY-EFFECT AND SUSCEPTIBILITY BIOMARKERS. DNA METHYLATION ANALYSIS HAS THE POTENTIAL FOR FUTURE APPLICATIONS IN RISK ASSESSMENT AND PREVENTION PROGRAMS CONDUCTED ON SUBJECTS EXPOSED TO HUMAN CARCINOGENS. 2005 19 3914 44 LIFETIME STRESS ACCELERATES EPIGENETIC AGING IN AN URBAN, AFRICAN AMERICAN COHORT: RELEVANCE OF GLUCOCORTICOID SIGNALING. BACKGROUND: CHRONIC PSYCHOLOGICAL STRESS IS ASSOCIATED WITH ACCELERATED AGING AND INCREASED RISK FOR AGING-RELATED DISEASES, BUT THE UNDERLYING MOLECULAR MECHANISMS ARE UNCLEAR. RESULTS: WE EXAMINED THE EFFECT OF LIFETIME STRESSORS ON A DNA METHYLATION-BASED AGE PREDICTOR, EPIGENETIC CLOCK. AFTER CONTROLLING FOR BLOOD CELL-TYPE COMPOSITION AND LIFESTYLE PARAMETERS, CUMULATIVE LIFETIME STRESS, BUT NOT CHILDHOOD MALTREATMENT OR CURRENT STRESS ALONE, PREDICTED ACCELERATED EPIGENETIC AGING IN AN URBAN, AFRICAN AMERICAN COHORT (N = 392). THIS EFFECT WAS PRIMARILY DRIVEN BY PERSONAL LIFE STRESSORS, WAS MORE PRONOUNCED WITH ADVANCING AGE, AND WAS BLUNTED IN INDIVIDUALS WITH HIGHER CHILDHOOD ABUSE EXPOSURE. HYPOTHESIZING THAT THESE EPIGENETIC EFFECTS COULD BE MEDIATED BY GLUCOCORTICOID SIGNALING, WE FOUND THAT A HIGH NUMBER (N = 85) OF EPIGENETIC CLOCK CPG SITES WERE LOCATED WITHIN GLUCOCORTICOID RESPONSE ELEMENTS. WE FURTHER EXAMINED THE FUNCTIONAL EFFECTS OF GLUCOCORTICOIDS ON EPIGENETIC CLOCK CPGS IN AN INDEPENDENT SAMPLE WITH GENOME-WIDE DNA METHYLATION (N = 124) AND GENE EXPRESSION DATA (N = 297) BEFORE AND AFTER EXPOSURE TO THE GLUCOCORTICOID RECEPTOR AGONIST DEXAMETHASONE. DEXAMETHASONE INDUCED DYNAMIC CHANGES IN METHYLATION IN 31.2 % (110/353) OF THESE CPGS AND TRANSCRIPTION IN 81.7 % (139/170) OF GENES NEIGHBORING EPIGENETIC CLOCK CPGS. DISEASE ENRICHMENT ANALYSIS OF THESE DEXAMETHASONE-REGULATED GENES SHOWED ENRICHED ASSOCIATION FOR AGING-RELATED DISEASES, INCLUDING CORONARY ARTERY DISEASE, ARTERIOSCLEROSIS, AND LEUKEMIAS. CONCLUSIONS: CUMULATIVE LIFETIME STRESS MAY ACCELERATE EPIGENETIC AGING, AN EFFECT THAT COULD BE DRIVEN BY GLUCOCORTICOID-INDUCED EPIGENETIC CHANGES. THESE FINDINGS CONTRIBUTE TO OUR UNDERSTANDING OF MECHANISMS LINKING CHRONIC STRESS WITH ACCELERATED AGING AND HEIGHTENED DISEASE RISK. 2015 20 1537 35 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