1 5656 94 SEX-DEPENDENT ASSOCIATION OF DNA METHYLATION IN THE CODING REGION OF THE CORTICOTROPIN-RELEASING HORMONE GENE AND SCHIZOPHRENIA SPECTRUM DISORDER. BACKGROUND: SCHIZOPHRENIA SPECTRUM DISORDER (SSD) IS A COMMON MENTAL DISORDER CAUSING SEVERE AND CHRONIC DISABILITY. EPIGENETIC CHANGES IN GENES RELATED TO THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS ARE BELIEVED TO PLAY AN IMPORTANT ROLE IN SSD PATHOGENESIS. THE METHYLATION STATUS OF THE CORTICOTROPIN-RELEASING HORMONE (CRH) GENE, WHICH IS CENTRAL TO THE HPA AXIS, HAS NOT BEEN INVESTIGATED IN PATIENTS WITH SSD. AIM: WE INVESTIGATED THE METHYLATION STATUS OF THE CODING REGION OF THE CRH GENE (HEREAFTER, CRH METHYLATION) USING PERIPHERAL BLOOD SAMPLES FROM PATIENTS WITH SSD. SUBJECTS AND METHODS: WE USED SODIUM BISULPHITE AND METHYLTARGET TO DETERMINE CRH METHYLATION AFTER COLLECTING PERIPHERAL BLOOD SAMPLES FROM 70 PATIENTS WITH SSD WHO HAD POSITIVE SYMPTOMS AND 68 HEALTHY CONTROLS. RESULTS: CRH METHYLATION WAS SIGNIFICANTLY INCREASED IN PATIENTS WITH SSD, ESPECIALLY IN MALE PATIENTS. CONCLUSIONS: DIFFERENCES IN CRH METHYLATION WERE DETECTABLE IN THE PERIPHERAL BLOOD OF PATIENTS WITH SSD. EPIGENETIC ABNORMALITIES IN THE CRH GENE WERE CLOSELY RELATED TO POSITIVE SYMPTOMS OF SSD, SUGGESTING THAT EPIGENETIC PROCESSES MAY MEDIATE THE PATHOPHYSIOLOGY OF SSD. 2023 2 344 33 ALTERED BDNF METHYLATION IN PATIENTS WITH CHRONIC MUSCULOSKELETAL PAIN AND HIGH BIOPSYCHOSOCIAL COMPLEXITY. PURPOSE: THE INTERMED INSTRUMENT, WHICH WAS DEVELOPED TO MEASURE PATIENT'S BIOPSYCHOSOCIAL (BPS) COMPLEXITY, REPRESENTS A POWERFUL DIAGNOSTIC AND THERAPEUTIC TOOL. EPIGENETIC CHANGES ARE THE INTERFACE BETWEEN SIGNALS FROM THE ENVIRONMENT AND GENETIC MODIFICATIONS, AFFECTING GENE EXPRESSION, IN PARTICULAR, BY DNA METHYLATION OF CPG DINUCLEOTIDES IN PROMOTOR REGIONS OF THE CORRESPONDING GENES. THE BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) GENE PLAYS A CRUCIAL ROLE IN THE CENTRAL SENSITIZATION (CS) OF PAIN. IN THIS STUDY, WE HYPOTHESIZED THAT CHRONIC PAIN MODIFIES THE METHYLATION LEVELS OF THE BDNF GENE IN A MANNER THAT IS INTERCONNECTED WITH THE BPS STATUS. PATIENTS AND METHODS: FIFTY-EIGHT CHRONIC MUSCULOSKELETAL PAIN PATIENTS (CMSP) WERE ENROLLED IN THE STUDY. DNA WAS EXTRACTED FROM BLOOD SAMPLES, THE METHYLATION LEVELS OF 13 CPG SITES IN THE BDNF PROMOTER WERE MEASURED BY PYROSEQUENCING, AND ASSOCIATION STUDIES WITH VARIOUS PATIENT PARAMETERS AND THE INTERMED SCORES WERE PERFORMED. RESULTS: INTERESTINGLY, A NEGATIVE CORRELATION (-0.40) WAS FOUND BETWEEN THE TOTAL INTERMED SCORES AND THE AVERAGE CPG METHYLATION VALUES OF THE BDNF GENE, BUT NO CORRELATION WAS OBSERVED WITH THE SEVERITY OF PAIN, DEGREE OF ANXIETY, DEPRESSION, OR KINESIOPHOBIA AND CATASTROPHISM. MOREOVER, THE ASSOCIATION WAS INDEPENDENT OF AGE, SEX AND LEVEL OF COMORBIDITIES. CONCLUSION: THIS RESULT SHOWS THAT CMSP, IN ASSOCIATION WITH ITS BIOPSYCHOSOCIAL CONTEXT, EPIGENETICALLY DECREASES THE DEGREE OF METHYLATION OF THE BDNF PROMOTER AND SHOULD THEREFORE INCREASE THE LEVEL OF BDNF TRANSCRIPTION. IT ALSO SUGGESTS A ROLE OF THE INTERMED TOOL TO DETECT A RELATIONSHIP BETWEEN THE BPS COMPLEXITY AND THE EPIGENETIC CONTROL OF A TARGET GENE. THE POSSIBLE UPREGULATION OF BDNF EXPRESSION MIGHT BE, AT LEAST IN PART, THE SIGNAL FOR CHRONIC PAIN-INDUCED CENTRAL SENSITIZATION (CS). THIS COULD PARTLY EXPLAIN WHY PATIENTS WITH A HIGHER LEVEL OF COMPLEXITY FEEL MORE PAIN THAN THOSE WITH LOWER COMPLEXITY. 2020 3 990 33 CHRONIC SOCIAL STRESS INDUCES DNA METHYLATION CHANGES AT AN EVOLUTIONARY CONSERVED INTERGENIC REGION IN CHROMOSOME X. CHRONIC STRESS RESULTING FROM PROLONGED EXPOSURE TO NEGATIVE LIFE EVENTS INCREASES THE RISK OF MOOD AND ANXIETY DISORDERS. ALTHOUGH CHRONIC STRESS CAN CHANGE GENE EXPRESSION RELEVANT FOR BEHAVIOR, MOLECULAR REGULATORS OF THIS CHANGE HAVE NOT BEEN FULLY DETERMINED. ONE PROCESS THAT COULD PLAY A ROLE IS DNA METHYLATION, AN EPIGENETIC PROCESS WHEREBY A METHYL GROUP IS ADDED ONTO NUCLEOTIDES, PREDOMINANTLY CYTOSINE IN THE CPG CONTEXT, AND WHICH CAN BE INDUCED BY CHRONIC STRESS. IT IS UNKNOWN TO WHAT EXTENT CHRONIC SOCIAL DEFEAT, A MODEL OF HUMAN SOCIAL STRESS, INFLUENCES DNA METHYLATION PATTERNS ACROSS THE GENOME. OUR STUDY ADDRESSED THIS QUESTION BY USING A TARGETED-CAPTURE APPROACH CALLED METHYL-SEQ TO INVESTIGATE DNA METHYLATION PATTERNS OF THE DENTATE GYRUS AT PUTATIVE REGULATORY REGIONS ACROSS THE MOUSE GENOME FROM MICE EXPOSED TO 14 DAYS OF SOCIAL DEFEAT. FINDINGS WERE REPLICATED IN INDEPENDENT COHORTS BY BISULFITE-PYROSEQUENCING. TWO DIFFERENTIALLY METHYLATED REGIONS (DMRS) WERE IDENTIFIED. ONE DMR WAS LOCATED AT INTRON 9 OF DROSHA, AND IT SHOWED REDUCED METHYLATION IN STRESSED MICE. THIS OBSERVATION REPLICATED IN ONE OF TWO INDEPENDENT COHORTS. A SECOND DMR WAS IDENTIFIED AT AN INTERGENIC REGION OF CHROMOSOME X, AND METHYLATION IN THIS REGION WAS INCREASED IN STRESSED MICE. THIS METHYLATION DIFFERENCE REPLICATED IN TWO INDEPENDENT COHORTS AND IN MAJOR DEPRESSIVE DISORDER (MDD) POSTMORTEM BRAINS. THESE RESULTS HIGHLIGHT A REGION NOT PREVIOUSLY KNOWN TO BE DIFFERENTIALLY METHYLATED BY CHRONIC SOCIAL DEFEAT STRESS AND WHICH MAY BE INVOLVED IN MDD. 2018 4 1967 33 EPIGENETIC ALTERATION OF THE DOPAMINE TRANSPORTER GENE IN ALCOHOL-DEPENDENT PATIENTS IS ASSOCIATED WITH AGE. CHRONIC ALCOHOL ABUSE AND DEPENDENCE ARE ASSOCIATED WITH DYSFUNCTIONAL DOPAMINERGIC NEUROTRANSMISSION IN MESOCORTICOLIMBIC CIRCUITS. GENETIC AND ENVIRONMENTAL FACTORS HAVE BEEN SHOWN TO MODULATE SUSCEPTIBILITY TO ALCOHOL DEPENDENCE, AND BOTH MAY ACT THROUGH EPIGENETIC MECHANISMS THAT CAN MODULATE GENE EXPRESSION, E.G. DNA METHYLATION AT CPG SITES. RECENT STUDIES HAVE SUGGESTED THAT DNA METHYLATION PATTERNS MAY CHANGE OVER TIME. HOWEVER, FEW DATA ARE AVAILABLE CONCERNING THE RATE OF THESE CHANGES IN SPECIFIC GENES. A RECENT STUDY FOUND THAT HYPERMETHYLATION OF THE PROMOTER OF THE DOPAMINE TRANSPORTER (DAT) GENE WAS POSITIVELY CORRELATED WITH ALCOHOL DEPENDENCE AND NEGATIVELY CORRELATED WITH ALCOHOL CRAVING. THE AIM OF THE PRESENT STUDY WAS TO REPLICATE THESE FINDINGS IN A LARGER SAMPLE OF ALCOHOL-DEPENDENT PATIENTS AND POPULATION-BASED CONTROLS MATCHED FOR AGE AND SEX. NO DIFFERENCE IN METHYLATION LEVEL WAS OBSERVED BETWEEN PATIENTS AND CONTROLS, AND NO DIFFERENCE IN METHYLATION LEVEL WAS OBSERVED BEFORE AND AFTER ALCOHOL WITHDRAWAL IN PATIENTS. HOWEVER, PATIENTS WITH MORE SEVERE CRAVING SHOWED A TREND TOWARDS LOWER DAT METHYLATION LEVELS (P = 0.07), WHICH IS CONSISTENT WITH PREVIOUS FINDINGS. FURTHERMORE, IN OUR OVERALL SAMPLE, DAT METHYLATION LEVELS INCREASED WITH AGE. INTERESTINGLY, A SEPARATE ANALYSIS OF PATIENTS SUGGESTED THAT THIS FINDING WAS MAINLY DRIVEN BY THE PATIENT GROUP. ALTHOUGH THE PRESENT DATA DO NOT CLARIFY WHETHER CHRONIC ALCOHOL ABUSE IS RESPONSIBLE FOR THIS PHENOMENON OR MERELY ENHANCES AN AGEING-SPECIFIC PROCESS, OUR FINDINGS SUGGEST THAT HYPERMETHYLATION IN ALCOHOL-DEPENDENT PATIENTS IS A CONSEQUENCE, RATHER THAN A CAUSE, OF THE DISORDER. 2014 5 3412 33 HPA AXIS REGULATION AND EPIGENETIC PROGRAMMING OF IMMUNE-RELATED GENES IN CHRONICALLY STRESSED AND NON-STRESSED MID-LIFE WOMEN. HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS DYSREGULATION HAS BEEN ASSOCIATED WITH ALTERED IMMUNE FUNCTION, BUT THE UNDERLYING MOLECULAR MECHANISMS ARE UNCLEAR. EPIGENETIC PROCESSES, INCLUDING DNA METHYLATION, RESPOND TO THE GLUCOCORTICOID END-PRODUCTS OF THE HPA AXIS (CORTISOL IN HUMANS) AND COULD BE INVOLVED IN THIS NEUROENDOCRINE-IMMUNE CROSSTALK. HERE WE EXAMINED THE EXTENT TO WHICH VARIATIONS IN HPA AXIS REGULATION ARE ASSOCIATED WITH PERIPHERAL BLOOD DNA (CPG) METHYLATION CHANGES IN 57 CHRONICALLY STRESSED CAREGIVERS AND 67 CONTROL WOMEN. DNA METHYLATION WAS DETERMINED WITH THE ILLUMINA 450K ARRAY FOR A PANEL OF GENES INVOLVED IN HPA AXIS AND IMMUNE FUNCTION. HPA AXIS FEEDBACK WAS ASSESSED WITH THE LOW-DOSE DEXAMETHASONE SUPPRESSION TEST (DST), MEASURING THE EXTENT TO WHICH CORTISOL SECRETION IS SUPPRESSED BY THE SYNTHETIC GLUCOCORTICOID DEXAMETHASONE. AFTER MULTIPLE TESTING CORRECTION IN THE ENTIRE COHORT, HIGHER POST-DST CORTISOL, REFLECTING BLUNTED HPA AXIS NEGATIVE FEEDBACK, BUT NOT BASELINE WAKING CORTISOL, WAS ASSOCIATED WITH LOWER DNA METHYLATION AT EIGHT TNF AND TWO FKBP5 CPG SITES. CAREGIVER GROUP STATUS WAS ASSOCIATED WITH LOWER METHYLATION AT TWO IL6 CPG SITES. SINCE ASSOCIATIONS WERE MOST ROBUST WITH TNF METHYLATION (32% OF THE 450K-COVERED SITES), WE FURTHER EXAMINED FUNCTIONALITY OF THIS EPIGENETIC SIGNATURE IN CULTURED PERIPHERAL BLOOD MONONUCLEAR CELLS IN 33 PARTICIPANTS; INTRIGUINGLY, LOWER TNF METHYLATION RESULTED IN HIGHER EX VIVO TNF MRNA FOLLOWING IMMUNE STIMULATION. TAKEN TOGETHER, OUR FINDINGS LINK CHRONIC STRESS AND HPA AXIS REGULATION WITH EPIGENETIC SIGNATURES AT IMMUNE-RELATED GENES, THEREBY PROVIDING NOVEL INSIGHTS INTO HOW ABERRANT HPA AXIS FUNCTION MAY CONTRIBUTE TO HEIGHTENED INFLAMMATION AND DISEASE RISK. 2021 6 2371 33 EPIGENETIC REGULATION OF THE GLUCOCORTICOID RECEPTOR PROMOTER 1(7) IN ADULT RATS. REGULATION OF GLUCOCORTICOID RECEPTOR (GR) LEVELS IS AN IMPORTANT STRESS ADAPTATION MECHANISM. TRANSCRIPTION FACTOR NFGI-A AND ENVIRONMENTALLY INDUCED GR PROMOTER 1 7 METHYLATION HAVE BEEN IMPLICATED IN FINE-TUNING THE EXPRESSION OF GR 1 7 TRANSCRIPTS. HERE, WE INVESTIGATED GR PROMOTER 1 7 METHYLATION AND GR 1 7 EXPRESSION IN ADULT RATS EXPOSED TO EITHER ACUTE OR CHRONIC STRESS PARADIGMS. A STRONG NEGATIVE CORRELATION WAS OBSERVED BETWEEN THE SUM OF PROMOTER-WIDE METHYLATION LEVELS AND GR 1 7 TRANSCRIPT LEVELS, INDEPENDENT OF THE STRESSOR. METHYLATION OF INDIVIDUAL SITES DID NOT, HOWEVER, CORRELATE WITH TRANSCRIPT LEVELS. THIS SUGGESTED THAT PROMOTER 1 7 WAS DIRECTLY REGULATED BY PROMOTER-WIDE DNA METHYLATION. ALTHOUGH ACUTE STRESS INCREASED NGFI-A EXPRESSION IN THE HYPOTHALAMIC PARAVENTRICULAR NUCLEUS (PVN), GR 1 7 TRANSCRIPT LEVELS REMAINED UNAFFECTED DESPITE LOW METHYLATION LEVELS. ACUTE STRESS HAD LITTLE EFFECT ON THESE LOW METHYLATION LEVELS, EXCEPT AT FOUR HIPPOCAMPAL CPGS. CHRONIC STRESS ALTERED THE CORTICOSTERONE RESPONSE TO AN ACUTE STRESSOR. IN THE ADRENAL AND PITUITARY GLANDS, BUT NOT IN THE BRAIN, THIS WAS ACCOMPANIED BY AN INCREASE IN METHYLATION LEVELS IN ORCHESTRATED CLUSTERS RATHER THAN INDIVIDUAL CPGS. PVN METHYLATION LEVELS, UNAFFECTED BY ACUTE OR CHRONIC STRESS, WERE SIGNIFICANTLY MORE VARIABLE WITHIN- THAN BETWEEN-GROUPS, SUGGESTING THAT THEY WERE INSTATED PROBABLY DURING THE PERINATAL PERIOD AND REPRESENT A PRE-ESTABLISHED TRAIT. THUS, IN ADDITION TO THE KNOWN PERINATAL PROGRAMMING, THE GR 1 7 PROMOTER IS EPIGENETICALLY REGULATED BY CHRONIC STRESS IN ADULTHOOD, AND RETAINS PROMOTER-WIDE TISSUE-SPECIFIC PLASTICITY. DIFFERENCES IN METHYLATION SUSCEPTIBILITY BETWEEN THE PVN IN THE PERINATAL PERIOD AND THE PERIPHERAL HPA AXIS TISSUES IN ADULTHOOD MAY REPRESENT AN IMPORTANT "TRAIT" VS. "STATE" REGULATION OF THE GR GENE. 2012 7 1599 35 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 8 3462 32 HYPOTHALAMIC NR3C1 DNA METHYLATION IN RATS EXPOSED TO PRENATAL STRESS. BACKGROUND: HUMAN AND ANIMAL STUDIES HAVE INDICATED THAT MATERNAL PRENATAL STRESS (PS) HAS MOLECULAR AND BEHAVIORAL EFFECTS DURING PREGNANCY AND EARLY LIFE. THE PRESENT STUDY AIMED TO EVALUATE THE EPIGENETIC CHANGES OF THE NR3C1 GENE INVOLVED IN THE HPA AXIS IN THE HYPOTHALAMIC TISSUES OF RATS EXPOSED TO PS INDUCED BY CHRONIC UNPREDICTABLE MILD STRESS (CUMS). BEHAVIORAL AND MOLECULAR EFFECTS OF THESE CHANGES ON THE NEXT GENERATION WERE ALSO ASSESSED. METHODS AND RESULTS: CUMS PROTOCOL WAS USED TO GENERATE STRESS IN PREGNANT WISTAR RATS. TO DETERMINE THE EFFECTS OF STRESS ON ANHEDONIA AND MOVEMENT, SUCROSE PREFERENCE TEST, FORCED SWIMMING TEST, AND OPEN FIELD TEST WERE PERFORMED. FOLLOWING THESE BEHAVIORAL EXPERIMENTS, BISULFITE SEQUENCING PCR FOR DNA METHYLATION LEVELS OF THE NR3C1 GENE, RT-QPCR FOR MRNA LEVELS, AND WESTERN BLOT TECHNIQUES FOR PROTEIN ANALYSIS WERE USED IN THE HYPOTHALAMIC TISSUE OF SACRIFICED RATS. DEPRESSION-LIKE BEHAVIORS WERE EVIDENT IN THE BEHAVIORAL TESTS OF STRESS-EXPOSED MOTHERS AND PUPS. IN PS-EXPOSED PUPS, HYPOTHALAMIC NR3C1 PROMOTER METHYLATION WAS HIGHER, AND NR3C1 MRNA LEVELS AND NR3C1 PROTEIN LEVELS WERE LOWER COMPARED WITH CONTROLS, REGARDLESS OF SEX. CONCLUSION: OUR RESULTS CONFIRM THE RELATIONSHIP BETWEEN PS AND EPIGENETIC CHANGES OF HPA AXIS-RELATED GENES AND SHOW THAT NR3C1 GENE METHYLATION STATUS IN PUPS IS SENSITIVE TO PS DURING PREGNANCY. ENVIRONMENTAL MATERNAL STRESS MAY HAVE TRANSGENERATIONAL EFFECTS THAT ARE POTENTIALLY ASSOCIATED WITH ADVERSE OUTCOMES IN THE PUPS. 2022 9 886 34 CHRONIC CORTICOSTERONE EXPOSURE INCREASES EXPRESSION AND DECREASES DEOXYRIBONUCLEIC ACID METHYLATION OF FKBP5 IN MICE. THERE IS EVIDENCE FOR HYPERCORTISOLEMIA PLAYING A ROLE IN THE GENERATION OF PSYCHIATRIC SYMPTOMS AND FOR EPIGENETIC VARIATION WITHIN HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS GENES MEDIATING BEHAVIORAL CHANGES. WE TESTED THE HYPOTHESIS THAT EXPRESSION CHANGES WOULD BE INDUCED IN FKBP5 AND OTHER HPA AXIS GENES BY CHRONIC EXPOSURE TO CORTICOSTERONE AND THAT THESE CHANGES WOULD OCCUR THROUGH THE EPIGENETIC MECHANISM OF LOSS OR GAIN OF DNA METHYLATION (DNAM). WE ADMINISTERED CORTICOSTERONE (CORT) TO C57BL/6J MICE VIA THEIR DRINKING WATER FOR 4 WK AND TESTED FOR BEHAVIORAL AND PHYSIOLOGICAL CHANGES AND CHANGES IN GENE EXPRESSION LEVELS USING RNA EXTRACTED FROM HIPPOCAMPUS, HYPOTHALAMUS, AND BLOOD FOR THE FOLLOWING HPA GENES: FKBP5, NR3C1, HSP90, CRH, AND CRHR1. THE CORT MICE EXHIBITED ANXIETY-LIKE BEHAVIOR IN THE ELEVATED PLUS MAZE TEST. CHRONIC EXPOSURE TO CORT ALSO CAUSED A SIGNIFICANT DECREASE IN THE HIPPOCAMPAL AND BLOOD MRNA LEVELS OF NR3C1 AND A DECREASE IN HSP90 IN BLOOD AND CAUSED AN INCREASE IN FKBP5 FOR ALL TISSUES. DIFFERENCES WERE SEEN IN FKBP5 METHYLATION IN HIPPOCAMPUS AND HYPOTHALAMUS. TO ISOLATE A SINGLE-CELL TYPE, WE FOLLOWED UP WITH AN HT-22 MOUSE HIPPOCAMPAL NEURONAL CELL LINE EXPOSED TO CORT. AFTER 7 D, WE OBSERVED A 2.4-FOLD INCREASE IN FKBP5 EXPRESSION AND A DECREASE IN DNAM. IN THE CORT-TREATED MICE, WE ALSO OBSERVED CHANGES IN BLOOD DNAM IN FKBP5. OUR RESULTS SUGGEST DNAM PLAYS A ROLE IN MEDIATING EFFECTS OF GLUCOCORTICOID EXPOSURE ON FKBP5 FUNCTION, WITH POTENTIAL CONSEQUENCES FOR BEHAVIOR. 2010 10 2472 26 EPIGENETIC TRANSMISSION OF THE IMPACT OF EARLY STRESS ACROSS GENERATIONS. BACKGROUND: TRAUMATIC EXPERIENCES IN EARLY LIFE ARE RISK FACTORS FOR THE DEVELOPMENT OF BEHAVIORAL AND EMOTIONAL DISORDERS. SUCH DISORDERS CAN PERSIST THROUGH ADULTHOOD AND HAVE OFTEN BEEN REPORTED TO BE TRANSMITTED ACROSS GENERATIONS. METHODS: TO INVESTIGATE THE TRANSGENERATIONAL EFFECT OF EARLY STRESS, MICE WERE EXPOSED TO CHRONIC AND UNPREDICTABLE MATERNAL SEPARATION FROM POSTNATAL DAY 1 TO 14. RESULTS: WE SHOW THAT CHRONIC AND UNPREDICTABLE MATERNAL SEPARATION INDUCES DEPRESSIVE-LIKE BEHAVIORS AND ALTERS THE BEHAVIORAL RESPONSE TO AVERSIVE ENVIRONMENTS IN THE SEPARATED ANIMALS WHEN ADULT. MOST OF THE BEHAVIORAL ALTERATIONS ARE FURTHER EXPRESSED BY THE OFFSPRING OF MALES SUBJECTED TO MATERNAL SEPARATION, DESPITE THE FACT THAT THESE MALES ARE REARED NORMALLY. CHRONIC AND UNPREDICTABLE MATERNAL SEPARATION ALSO ALTERS THE PROFILE OF DNA METHYLATION IN THE PROMOTER OF SEVERAL CANDIDATE GENES IN THE GERMLINE OF THE SEPARATED MALES. COMPARABLE CHANGES IN DNA METHYLATION ARE ALSO PRESENT IN THE BRAIN OF THE OFFSPRING AND ARE ASSOCIATED WITH ALTERED GENE EXPRESSION. CONCLUSIONS: THESE FINDINGS HIGHLIGHT THE NEGATIVE IMPACT OF EARLY STRESS ON BEHAVIORAL RESPONSES ACROSS GENERATIONS AND ON THE REGULATION OF DNA METHYLATION IN THE GERMLINE. 2010 11 3080 31 GENOME-WIDE METHYLATION IN ALCOHOL USE DISORDER SUBJECTS: IMPLICATIONS FOR AN EPIGENETIC REGULATION OF THE CORTICO-LIMBIC GLUCOCORTICOID RECEPTORS (NR3C1). ENVIRONMENTAL FACTORS, INCLUDING SUBSTANCE ABUSE AND STRESS, CAUSE LONG-LASTING CHANGES IN THE REGULATION OF GENE EXPRESSION IN THE BRAIN VIA EPIGENETIC MECHANISMS, SUCH AS DNA METHYLATION. WE EXAMINED GENOME-WIDE DNA METHYLATION PATTERNS IN THE PREFRONTAL CORTEX (PFC, BA10) OF 25 PAIRS OF CONTROL AND INDIVIDUALS WITH ALCOHOL USE DISORDER (AUD), USING THE INFINIUM((R)) METHYLATIONEPIC BEADCHIP. WE IDENTIFIED 5254 DIFFERENTIALLY METHYLATED CPGS (P(NOMINAL) < 0.005). BIOINFORMATIC ANALYSES HIGHLIGHTED BIOLOGICAL PROCESSES CONTAINING GENES RELATED TO STRESS ADAPTATION, INCLUDING THE GLUCOCORTICOID RECEPTOR (ENCODED BY NR3C1). CONSIDERING THAT ALCOHOL IS A STRESSOR, WE FOCUSED OUR ATTENTION ON DIFFERENTIALLY METHYLATED REGIONS OF THE NR3C1 GENE AND VALIDATED THE DIFFERENTIAL METHYLATION OF SEVERAL GENES IN THE NR3C1 NETWORK. CHRONIC ALCOHOL DRINKING RESULTS IN A SIGNIFICANT INCREASED METHYLATION OF THE NR3C1 EXON VARIANT 1(H), WITH A PARTICULAR INCREASE IN THE LEVELS OF 5-HYDROXYMETHYLCYTOSINE OVER 5-METHYLCYTOSINE. THESE CHANGES IN DNA METHYLATION WERE ASSOCIATED WITH REDUCED NR3C1 MRNA AND PROTEIN EXPRESSION LEVELS IN PFC, AS WELL AS OTHER CORTICO-LIMBIC REGIONS OF AUD SUBJECTS WHEN COMPARED WITH CONTROLS. FURTHERMORE, WE SHOW THAT THE EXPRESSION OF SEVERAL STRESS-RESPONSIVE GENES (E.G., CRF, POMC, AND FKBP5) IS ALTERED IN THE PFC OF AUD SUBJECTS. THESE STRESS-RESPONSE GENES WERE ALSO CHANGED IN THE HIPPOCAMPUS, A REGION THAT IS HIGHLY SUSCEPTIBLE TO STRESS. THESE DATA SUGGEST THAT ALCOHOL-DEPENDENT ABERRANT DNA METHYLATION OF NR3C1 AND CONSEQUENT CHANGES IN OTHER STRESS-RELATED GENES MIGHT BE FUNDAMENTAL IN THE PATHOPHYSIOLOGY OF AUD AND LAY THE GROUNDWORK FOR TREATMENTS TARGETING THE EPIGENETIC MECHANISMS REGULATING NR3C1 IN AUD. 2021 12 1503 26 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 13 6311 25 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 14 1418 32 DIFFERENCES IN DNA METHYLATION REPROGRAMMING UNDERLIE THE SEXUAL DIMORPHISM OF BEHAVIORAL DISORDER CAUSED BY PRENATAL STRESS IN RATS. PRENATAL STRESS (PS) CAN LEAD TO NEUROENDOCRINE AND EMOTIONAL DISORDERS LATER IN ADOLESCENCE. SEXUAL DIMORPHISM IN THESE NEURODEVELOPMENTAL OUTCOMES HAVE BEEN OBSERVED; HOWEVER, THE UNDERLYING MECHANISMS ARE NOT FULLY UNDERSTOOD. TO ADDRESS THIS ISSUE, WE INVESTIGATED WHETHER THERE ARE SEX DIFFERENCES IN EPIGENETIC REPROGRAMMING IN RATS EXPOSED TO PS. PREGNANT FEMALE RATS WERE SUBJECTED TO CHRONIC RESTRAINT STRESS FROM GESTATIONAL DAY (G)12 TO G18. FROM POSTNATAL DAY (P)38 TO P45, SUBGROUPS OF OFFSPRING INCLUDING BOTH MALES AND FEMALES WERE SUBJECTED TO BEHAVIORAL TESTING AND BRAIN TISSUE SPECIMENS WERE ANALYZED BY DNA PYROSEQUENCING, WESTERN BLOTTING, AND GOLGI STAINING TO ASSESS CHANGES IN METHYLATION PATTERN OF GLUCOCORTICOID RECEPTOR (GR) GENE, EXPRESSION OF DNA METHYLTRANSFERASE (DNMT) AND DNA DEMETHYLASE, AND DENDRITE MORPHOLOGY, RESPECTIVELY. THE DNA METHYLTRANSFERASE INHIBITOR DECITABINE WAS ADMINISTERED TO RATS PRIOR TO PS TO FURTHER EVALUATE THE ROLE OF METHYLATION IN THE SEXUALLY DIMORPHIC EFFECTS OF PS. THE RESULTS SHOWED THAT PS INCREASED ANXIETY-LIKE BEHAVIOR IN OFFSPRING, ESPECIALLY IN FEMALES, WHILE DEPRESSION-LIKE BEHAVIOR WAS INCREASED IN MALE OFFSPRING COMPARED TO CONTROL LITTERMATES. THE METHYLATION PATTERN IN THE PROMOTER REGION OF THE GR GENE DIFFERED BETWEEN MALES AND FEMALES. SEX-SPECIFIC CHANGES IN THE EXPRESSION OF DNMTS (DNMT1 AND DNMT3A) AND DNA DEMETHYLASE (TET METHYLCYTOSINE DIOXYGENASE 2) WERE ALSO OBSERVED. INTERESTINGLY, DECITABINE ALLEVIATED THE BEHAVIORAL DISORDER CAUSED BY PS AND RESTORED DENDRITE DENSITY AND MORPHOLOGY IN FEMALE BUT NOT MALE RATS. THESE FINDINGS SUGGEST THAT DIFFERENT CHANGE PATTERNS OF DNMT AND DEMETHYLASE IN THE TWO SEXES AFTER PS ARE RESPONSIBLE FOR THE SEXUALLY DIMORPHISM, WHICH COULD HAVE IMPLICATIONS FOR THE CLINICAL MANAGEMENT OF STRESS-RELATED DISORDERS. 2020 15 5682 29 SHORT-TERM CHANGES IN GLOBAL METHYLATION AND HYDROXYMETHYLATION DURING ALCOHOL DETOXIFICATION. ALCOHOL DEPENDENCE IS A COMMON PUBLIC HEALTH PROBLEM AND EPIGENETICS MAY OFFER NEW ASPECTS IN UNDERSTANDING THE BIOLOGICAL AND GENETIC UNDERPINNINGS AND IMPROVE TREATMENT OF THIS COMPLEX DISEASE. SUPPOSEDLY, METHYLATION AND HYDROXYMETHYLATION ARE ALTERED IN BRAIN TISSUES AND IN SYNAPSE-RELATED GENES DUE TO CHRONIC ALCOHOL INTAKE AND DURING WITHDRAWAL. TO ASSESS POTENTIAL EPIGENETIC CHANGES AFTER CESSATION OF CHRONIC ALCOHOL INTAKE, WE COMPARED 23 ALCOHOL-DEPENDENT INDIVIDUALS DURING INPATIENT ALCOHOL DETOXIFICATION WITH 13 CAREFULLY MATCHED CONTROLS. BLOOD SAMPLES WERE TAKEN ON THE DAY OF ADMISSION, AFTER ONE AND AFTER TWO WEEKS AT THE END OF INPATIENT TREATMENT. GENOME-WIDE GLOBAL METHYLATION AND GLOBAL DNA HYDROXYMETHYLATION WERE COMPARED ACROSS GROUPS. THERE WERE SIGNIFICANT DIFFERENCES IN GLOBAL METHYLATION ACROSS TIME FROM ADMISSION TO ONE AND TWO WEEKS OF INPATIENT WITHDRAWAL (P < 0.001). THESE FINDINGS WERE PARALLELED TO CHANGES IN GLOBAL DNA HYDROXYMETHYLATION ACROSS TIME WHEN AGE WAS EMPLOYED AS A COFACTOR (P < 0.001). SEVERAL POTENTIALLY INFLUENCING VARIABLES LIKE SEVERITY OF WITHDRAWAL, DOSE OF WITHDRAWAL MEDICATION AND ALCOHOL INTAKE BEFORE ADMISSION DID NOT YIELD SIGNIFICANT INFLUENCE ON EPIGENETIC CHANGES. THE RESULTS CONFIRM PREVIOUS FINDINGS OF SIGNIFICANT ALTERATIONS OF EPIGENETIC PATTERNS DURING ALCOHOL INTOXICATION AND PRESENT FOR THE FIRST TIME HYDROXYMETHYLATION CHANGES IN THESE INDIVIDUALS. 2019 16 1537 27 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 17 4879 19 OVERLAPPING SIGNATURES OF CHRONIC PAIN IN THE DNA METHYLATION LANDSCAPE OF PREFRONTAL CORTEX AND PERIPHERAL T CELLS. WE TESTED THE HYPOTHESIS THAT EPIGENETIC MECHANISMS IN THE BRAIN AND THE IMMUNE SYSTEM ARE ASSOCIATED WITH CHRONIC PAIN. GENOME-WIDE DNA METHYLATION ASSESSED IN 9 MONTHS POST NERVE-INJURY (SNI) AND SHAM RATS, IN THE PREFRONTAL CORTEX (PFC) AS WELL AS IN T CELLS REVEALED A VAST DIFFERENCE IN THE DNA METHYLATION LANDSCAPE IN THE BRAIN BETWEEN THE GROUPS AND A REMARKABLE OVERLAP (72%) BETWEEN DIFFERENTIALLY METHYLATED PROBES IN T CELLS AND PREFRONTAL CORTEX. DNA METHYLATION STATES IN THE PFC SHOWED ROBUST CORRELATION WITH PAIN SCORE OF ANIMALS IN SEVERAL GENES INVOLVED IN PAIN. FINALLY, ONLY 11 DIFFERENTIALLY METHYLATED PROBES IN T CELLS WERE SUFFICIENT TO DISTINGUISH SNI OR SHAM INDIVIDUAL RATS. THIS STUDY SUPPORTS THE PLAUSIBILITY OF DNA METHYLATION INVOLVEMENT IN CHRONIC PAIN AND DEMONSTRATES THE POTENTIAL FEASIBILITY OF DNA METHYLATION MARKERS IN T CELLS AS NONINVASIVE BIOMARKERS OF CHRONIC PAIN SUSCEPTIBILITY. 2016 18 287 30 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 19 4093 24 MATERNAL SEPARATION FOLLOWED BY CHRONIC MILD STRESS IN ADULTHOOD IS ASSOCIATED WITH CONCERTED EPIGENETIC REGULATION OF AP-1 COMPLEX GENES. DEPRESSION IS ONE OF THE MOST PREVALENT MENTAL DISEASES WORLDWIDE. PATIENTS WITH PSYCHIATRIC DISEASES OFTEN HAVE A HISTORY OF CHILDHOOD NEGLECT, INDICATING THAT EARLY-LIFE EXPERIENCES PREDISPOSE TO PSYCHIATRIC DISEASES IN ADULTHOOD. TWO STRONG MODELS WERE USED IN THE PRESENT STUDY: THE MATERNAL SEPARATION/EARLY DEPRIVATION MODEL (MS) AND THE CHRONIC MILD STRESS MODEL (CMS). IN BOTH MODELS, WE FOUND CHANGES IN THE EXPRESSION OF A NUMBER OF GENES SUCH AS CREB AND NPY. STRIKINGLY, THERE WAS A CLEAR REGULATION OF EXPRESSION OF FOUR GENES INVOLVED IN THE AP-1 COMPLEX: C-FOS, C-JUN, FOSB, AND JUN-B. INTERESTINGLY, DIFFERENT EXPRESSION LEVELS WERE OBSERVED DEPENDING ON THE MODEL, WHEREAS THE COMBINATION OF THE MODELS RESULTED IN A NORMAL LEVEL OF GENE EXPRESSION. THE EFFECTS OF MS AND CMS ON GENE EXPRESSION WERE ASSOCIATED WITH DISTINCT HISTONE METHYLATION/ACETYLATION PATTERNS OF ALL FOUR GENES. THE EPIGENETIC CHANGES, LIKE GENE EXPRESSION, WERE ALSO DEPENDENT ON THE SPECIFIC STRESSOR OR THEIR COMBINATION. THE OBTAINED RESULTS SUGGEST THAT SINGLE LIFE EVENTS LEAVE A MARK ON GENE EXPRESSION AND THE EPIGENETIC SIGNATURE OF GENE PROMOTERS, BUT A COMBINATION OF DIFFERENT STRESSORS AT DIFFERENT LIFE STAGES CAN FURTHER CHANGE GENE EXPRESSION THROUGH EPIGENETIC FACTORS, POSSIBLY CAUSING THE LONG-LASTING ADVERSE EFFECTS OF STRESS. 2021 20 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