1 2472 99 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 2 5397 39 REDUCED LEVELS OF MIRNAS 449 AND 34 IN SPERM OF MICE AND MEN EXPOSED TO EARLY LIFE STRESS. EXPOSURE OF MALE MICE TO EARLY LIFE STRESS ALTERS THE LEVELS OF SPECIFIC SPERM MIRNAS THAT PROMOTE STRESS-ASSOCIATED BEHAVIORS IN THEIR OFFSPRING. TO BEGIN TO EVALUATE WHETHER SIMILAR PHENOMENA OCCUR IN MEN, WE SEARCHED FOR SPERM MIRNA CHANGES THAT OCCUR IN BOTH MICE AND MEN EXPOSED TO EARLY LIFE STRESSORS THAT HAVE LONG-LASTING EFFECTS. FOR MEN, WE USED THE ADVERSE CHILDHOOD EXPERIENCE (ACE) QUESTIONNAIRE. IT REVEALS THE DEGREE OF ABUSIVE AND/OR DYSFUNCTIONAL FAMILY EXPERIENCES WHEN YOUNG, WHICH INCREASES RISKS OF DEVELOPING FUTURE PSYCHOLOGICAL AND PHYSICAL DISORDERS. FOR MALE MICE, WE USED ADOLESCENT CHRONIC SOCIAL INSTABILITY (CSI) STRESS, WHICH NOT ONLY ENHANCES SOCIABILITY DEFECTS FOR >1 YEAR, BUT ALSO ANXIETY AND DEFECTIVE SOCIABILITY IN FEMALE OFFSPRING FOR MULTIPLE GENERATIONS THROUGH THE MALE LINEAGE. HERE WE FOUND A STATISTICALLY SIGNIFICANT INVERSE CORRELATION BETWEEN LEVELS OF MULTIPLE MIRNAS OF THE MIR-449/34 FAMILY AND ACE SCORES OF CAUCASIAN MALES. REMARKABLY, WE FOUND MEMBERS OF THE SAME SPERM MIRNA FAMILY ARE ALSO REDUCED IN MICE EXPOSED TO CSI STRESS. THUS, FUTURE STUDIES SHOULD BE DESIGNED TO DIRECTLY TEST WHETHER REDUCED LEVELS OF THESE MIRNAS COULD BE USED AS UNBIASED INDICATORS OF CURRENT AND/OR EARLY LIFE EXPOSURE TO SEVERE STRESS. MOREOVER, AFTER MATING STRESSED MALE MICE, THESE SPERM MIRNA REDUCTIONS PERSIST IN BOTH EARLY EMBRYOS THROUGH AT LEAST THE MORULA STAGE AND IN SPERM OF MALES DERIVED FROM THEM, SUGGESTING THESE MIRNA CHANGES CONTRIBUTE TO TRANSMISSION OF STRESS PHENOTYPES ACROSS GENERATIONS. SINCE OFFSPRING OF MEN EXPOSED TO EARLY LIFE TRAUMA HAVE ELEVATED RISKS FOR PSYCHOLOGICAL DISORDERS, THESE FINDINGS RAISE THE POSSIBILITY THAT A PORTION OF THIS RISK MAY BE DERIVED FROM EPIGENETIC REGULATION OF THESE SPERM MIRNAS. 2018 3 4093 38 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 4 2021 32 EPIGENETIC CHANGES ASSOCIATED WITH DIFFERENT TYPES OF STRESSORS AND SUICIDE. STRESS IS ASSOCIATED WITH VARIOUS EPIGENETIC CHANGES. SOME STRESS-INDUCED EPIGENETIC CHANGES ARE HIGHLY DYNAMIC, WHEREAS OTHERS ARE ASSOCIATED WITH LASTING MARKS ON THE EPIGENOME. IN OUR STUDY, A COMPREHENSIVE NARRATIVE REVIEW OF THE LITERATURE WAS PERFORMED BY INVESTIGATING THE EPIGENETIC CHANGES THAT OCCUR WITH ACUTE STRESS, CHRONIC STRESS, EARLY CHILDHOOD STRESS, AND TRAUMATIC STRESS EXPOSURES, ALONG WITH EXAMINING THOSE OBSERVED IN POST-MORTEM BRAINS OR BLOOD SAMPLES OF SUICIDE COMPLETERS AND ATTEMPTERS. IN ADDITION, THE TRANSGENERATIONAL EFFECTS OF THESE CHANGES ARE REPORTED. FOR ALL TYPES OF STRESS STUDIES EXAMINED, THE GENES NR3C1, OXTR, SLC6A4, AND BDNF REPRODUCIBLY SHOWED EPIGENETIC CHANGES, WITH SOME MODIFICATIONS OBSERVED TO BE PASSED DOWN TO SUBSEQUENT GENERATIONS FOLLOWING STRESS EXPOSURES. THE AFOREMENTIONED GENES ARE KNOWN TO BE INVOLVED IN NEURONAL DEVELOPMENT AND HORMONAL REGULATION AND ARE ALL ASSOCIATED WITH SUSCEPTIBILITY TO MENTAL HEALTH DISORDERS INCLUDING DEPRESSION, ANXIETY, PERSONALITY DISORDERS, AND PTSD (POST-TRAUMATIC STRESS DISORDER). FURTHER RESEARCH IS WARRANTED IN ORDER TO DETERMINE THE SCOPE OF EPIGENETIC ACTIONABLE TARGETS IN INDIVIDUALS SUFFERING FROM THE LONG-LASTING EFFECTS OF STRESSFUL EXPERIENCES. 2023 5 2159 39 EPIGENETIC MECHANISMS IMPACTED BY CHRONIC STRESS ACROSS THE RODENT LIFESPAN. EXPOSURES TO STRESS AT ALL STAGES OF DEVELOPMENT CAN LEAD TO LONG-TERM BEHAVIOURAL EFFECTS, IN PART THROUGH CHANGES IN THE EPIGENOME. THIS REVIEW DESCRIBES RODENT RESEARCH SUGGESTING THAT STRESS IN PRENATAL, POSTNATAL, ADOLESCENT AND ADULT STAGES LEADS TO LONG-TERM CHANGES IN EPIGENETIC REGULATION IN THE BRAIN WHICH HAVE CAUSAL IMPACTS ON RODENT BEHAVIOUR. WE FOCUS ON STRESS-INDUCED EPIGENETIC CHANGES THAT HAVE BEEN LINKED TO BEHAVIOURAL DEFICITS INCLUDING POOR LEARNING AND MEMORY, AND INCREASED ANXIETY-LIKE AND DEPRESSIVE-LIKE BEHAVIOURS. INTERESTINGLY, ASPECTS OF THESE STRESS-INDUCED BEHAVIOURAL CHANGES CAN BE TRANSMITTED TO OFFSPRING ACROSS SEVERAL GENERATIONS, A PHENOMENON THAT HAS BEEN PROPOSED TO RESULT VIA EPIGENETIC MECHANISMS IN THE GERMLINE. HERE, WE ALSO DISCUSS EVIDENCE FOR THE DIFFERENTIAL IMPACT OF STRESS ON THE EPIGENOME IN MALES AND FEMALES, CONSCIOUS OF THE FACT THAT THE MAJORITY OF PUBLISHED STUDIES HAVE ONLY INVESTIGATED MALES. THIS HAS LED TO A LIMITED PICTURE OF THE EPIGENETIC IMPACT OF STRESS, HIGHLIGHTING THE NEED FOR FUTURE STUDIES TO INVESTIGATE FEMALES AS WELL AS MALES. 2022 6 5774 44 SPERM TRANSCRIPTIONAL STATE ASSOCIATED WITH PATERNAL TRANSMISSION OF STRESS PHENOTYPES. PATERNAL STRESS CAN INDUCE LONG-LASTING CHANGES IN GERM CELLS POTENTIALLY PROPAGATING HERITABLE CHANGES ACROSS GENERATIONS. TO DATE, NO STUDIES HAVE INVESTIGATED DIFFERENCES IN TRANSMISSION PATTERNS BETWEEN STRESS-RESILIENT AND -SUSCEPTIBLE MICE. WE TESTED THE HYPOTHESIS THAT TRANSCRIPTIONAL ALTERATIONS IN SPERM DURING CHRONIC SOCIAL DEFEAT STRESS (CSDS) TRANSMIT INCREASED SUSCEPTIBILITY TO STRESS PHENOTYPES TO THE NEXT GENERATION. WE DEMONSTRATE DIFFERENCES IN OFFSPRING FROM STRESSED FATHERS THAT DEPEND UPON PATERNAL CATEGORY (RESILIENT VS SUSCEPTIBLE) AND OFFSPRING SEX. IMPORTANTLY, ARTIFICIAL INSEMINATION REVEALS THAT SPERM MEDIATES SOME OF THE BEHAVIORAL PHENOTYPES SEEN IN OFFSPRING. USING RNA-SEQUENCING WE REPORT SUBSTANTIAL AND DISTINCT CHANGES IN THE TRANSCRIPTOMIC PROFILES OF SPERM FOLLOWING CSDS IN SUSCEPTIBLE VS RESILIENT FATHERS, WITH ALTERATIONS IN LONG NONCODING RNAS (LNCRNAS) PREDOMINATING ESPECIALLY IN SUSCEPTIBILITY. CORRELATION ANALYSIS REVEALED THAT THESE ALTERATIONS WERE ACCOMPANIED BY A LOSS OF REGULATION OF PROTEIN-CODING GENES BY LNCRNAS IN SPERM OF SUSCEPTIBLE MALES. WE ALSO IDENTIFY SEVERAL CO-EXPRESSION GENE MODULES THAT ARE ENRICHED IN DIFFERENTIALLY EXPRESSED GENES IN SPERM FROM EITHER RESILIENT OR SUSCEPTIBLE FATHERS. TAKEN TOGETHER, THESE STUDIES ADVANCE OUR UNDERSTANDING OF INTERGENERATIONAL EPIGENETIC TRANSMISSION OF BEHAVIORAL EXPERIENCE.SIGNIFICANCE STATEMENTTHIS MANUSCRIPT CONTRIBUTES TO THE COMPLEX FACTORS THAT INFLUENCE THE PATERNAL TRANSMISSION OF STRESS PHENOTYPES. BY LEVERAGING THE SEGREGATION OF MALES EXPOSED TO CHRONIC SOCIAL DEFEAT STRESS INTO EITHER RESILIENT OR SUSCEPTIBLE CATEGORIES WE WERE ABLE TO IDENTIFY THE PHENOTYPIC DIFFERENCES IN THE PATERNAL TRANSMISSION OF STRESS PHENOTYPES ACROSS GENERATIONS BETWEEN THE TWO LINEAGES. IMPORTANTLY, THIS WORK ALSO ALLUDES TO THE SIGNIFICANCE OF BOTH LONG NONCODING RNAS AND PROTEIN CODING GENES MEDIATING THE PATERNAL TRANSMISSION OF STRESS. THE KNOWLEDGE GAINED FROM THESE DATA IS OF PARTICULAR INTEREST IN UNDERSTANDING THE RISK FOR THE DEVELOPMENT OF PSYCHIATRIC DISORDERS SUCH AS ANXIETY AND DEPRESSION. 2021 7 1981 42 EPIGENETIC ALTERATIONS IN DNA AND HISTONE MODIFICATIONS CAUSED BY DEPRESSION AND ANTIDEPRESSANT DRUGS: LESSONS FROM THE RODENT MODELS. EPIGENETIC MODIFICATIONS REGULATE CHROMATIN FOLDING AND FUNCTION. EPIGENETIC MECHANISMS REGULATE TRANSCRIPTION MEDIATING EFFECTS OF VARIOUS STIMULI ON GENE EXPRESSION. THESE MECHANISMS ARE INVOLVED IN TRANSCRIPTIONAL CONTROL IN VARIOUS PHYSIOLOGICAL AND PATHOLOGICAL CONDITIONS INCLUDING NEUROPSYCHIATRIC DISORDERS AND BEHAVIORAL ABNORMALITIES SUCH AS DEPRESSION. IN RODENTS, EXPOSURE TO CHRONIC SOCIAL STRESS WAS SHOWN TO INDUCE BEHAVIORAL IMPAIRMENTS AND MEMORY/LEARNING DEFICITS THAT RESEMBLE DEPRESSIVE-LIKE PHENOTYPE IN HUMANS. THE RODENT MODELS OF CHRONIC STRESS WERE WIDELY USED TO STUDY MOLECULAR MECHANISMS OF DEPRESSION. IN THESE MODELS, EARLY EXPOSURE TO CHRONIC STRESS SUCH AS PRENATAL OR POSTNATAL STRESS INDUCES LONG-TERM HYPERACTIVE STRESS RESPONSES, BEHAVIORAL ABNORMALITIES, AND FUNCTIONAL IMPAIRMENTS IN BRAIN FUNCTION THAT PERSIST IN ADULTHOOD. FURTHERMORE, THESE ALTERATIONS CAN BE TRANSMITTED TO OFFSPRING OF CHRONICALLY STRESSED ANIMALS ACROSS SEVERAL GENERATIONS. MOLECULAR STUDIES IN ANIMAL MODELS SHOWED THAT CHRONIC STRESS INDUCES STABLE EPIGENETIC CHANGES IN SPECIFIC BRAIN REGIONS, PRIMARILY IN THE LIMBIC SYSTEM. THESE CHANGES LEAD TO LONG-LASTING ABNORMALITIES IN BEHAVIOR THAT PERSIST IN ADULTHOOD AND CAN BE TRANSMITTED TO OFFSPRING. TREATMENT WITH EPIGENETICALLY ACTIVE ANTIDEPRESSANTS DISRUPTS THE ABNORMAL STRESS-INDUCED EPIGENETIC PROGRAMMING AND PROVIDES EPIGENETIC PATTERNS THAT RESEMBLE EPIGENETIC BACKGROUND OF STRESS RESILIENT INDIVIDUALS. 2017 8 5199 42 PRENATAL MATERNAL STRESS IS ASSOCIATED WITH INCREASED SENSITIVITY TO NEUROPATHIC PAIN AND SEX-SPECIFIC CHANGES IN SUPRASPINAL MRNA EXPRESSION OF EPIGENETIC- AND STRESS-RELATED GENES IN ADULTHOOD. EXPOSURE TO PRENATAL MATERNAL STRESS IMPACTS ADULT BEHAVIORAL OUTCOMES AND HAS BEEN SUGGESTED AS A RISK FACTOR FOR CHRONIC PAIN. HOWEVER, THE NEUROBIOLOGICAL MECHANISMS IMPLICATED ARE NOT WELL-CHARACTERIZED. IN THIS STUDY, WE ANALYZED THE EFFECT OF A PRENATAL MATERNAL STRESS ON THE DEVELOPMENT OF NEUROPATHIC PAIN-RELATED BEHAVIOURS AND GENE EXPRESSION IN THE FRONTAL CORTEX AND HIPPOCAMPUS IN ADULT OFFSPRING FOLLOWING CHRONIC CONSTRICTION INJURY OF THE SCIATIC NERVE IN MALE AND FEMALE CD1 MICE. NERVE INJURY-INDUCED MECHANICAL HYPERSENSITIVITY WAS AMPLIFIED IN BOTH MALE AND FEMALE PRENATALLY-STRESSED OFFSPRING, SUGGESTING THAT PRENATAL STRESS EXACERBATES PAIN AFTER INJURY. ANALYSIS OF MRNA EXPRESSION OF GENES RELATED TO EPIGENETIC REGULATION AND STRESS RESPONSES IN THE FRONTAL CORTEX AND HIPPOCAMPUS, BRAIN STRUCTURES IMPLICATED IN CHRONIC PAIN, SHOWED DISTINCT SEX AND REGION-SPECIFIC PATTERNS OF DYSREGULATION. IN GENERAL, MRNA EXPRESSION WAS MOST FREQUENTLY ALTERED IN THE MALE HIPPOCAMPUS AND EFFECTS OF PRENATAL STRESS WERE MORE PREVALENT THAN EFFECTS OF NERVE INJURY IN BOTH SUPRASPINAL AREAS. THESE FINDINGS DEMONSTRATE THE IMPACT OF PRENATAL STRESS ON BEHAVIORAL SENSITIVITY TO A PAINFUL INJURY. CHANGES IN THE EXPRESSION OF EPIGENETIC- AND STRESS-RELATED GENES SUGGEST A POSSIBLE MECHANISM BY WHICH THE EARLY LIFE STRESS BECOMES EMBEDDED IN THE CENTRAL NERVOUS SYSTEM. INCREASED UNDERSTANDING OF THE INTERACTIONS AMONG EARLY-LIFE STRESS, SEX, AND PAIN MAY LEAD TO THE IDENTIFICATION OF NOVEL THERAPEUTIC TARGETS AND EPIGENETIC DRUGS FOR THE TREATMENT OF CHRONIC PAIN DISORDERS. 2020 9 5166 28 PRECONCEPTION PATERNAL ALCOHOL EXPOSURE EXERTS SEX-SPECIFIC EFFECTS ON OFFSPRING GROWTH AND LONG-TERM METABOLIC PROGRAMMING. BACKGROUND: ALTHOUGH CLINICAL DATA SUPPORT AN ASSOCIATION BETWEEN PATERNAL ALCOHOL USE AND DEFICITS IN CHILD NEUROCOGNITIVE DEVELOPMENT, THE RELATIONSHIP BETWEEN PATERNAL DRINKING AND ALCOHOL-INDUCED GROWTH PHENOTYPES REMAINS CHALLENGING TO DEFINE. USING AN ESTABLISHED MOUSE MODEL OF CHRONIC EXPOSURE, PREVIOUS WORK BY OUR GROUP HAS LINKED PRECONCEPTION PATERNAL ALCOHOL USE TO SEX-SPECIFIC PATTERNS OF FETAL GROWTH RESTRICTION AND PLACENTAL DYSFUNCTION. THE AIM OF THE PRESENT STUDY WAS TO INVESTIGATE THE LONG-TERM IMPACT OF CHRONIC PRECONCEPTION PATERNAL ALCOHOL USE ON OFFSPRING GROWTH AND METABOLIC PROGRAMMING. RESULTS: PRECONCEPTION PATERNAL ALCOHOL EXPOSURE INDUCED A PROLONGED PERIOD OF FETAL GESTATION AND AN INCREASED INCIDENCE OF INTRAUTERINE GROWTH RESTRICTION, WHICH AFFECTED THE MALE OFFSPRING TO A GREATER EXTENT THAN THE FEMALES. WHILE THE FEMALE OFFSPRING OF ETHANOL-EXPOSED MALES WERE ABLE TO MATCH THE BODY WEIGHTS OF THE CONTROLS WITHIN THE FIRST 2 WEEKS OF POSTNATAL LIFE, MALE OFFSPRING CONTINUED TO DISPLAY AN 11% REDUCTION IN WEIGHT AT 5 WEEKS OF AGE AND A 6% REDUCTION AT 8 WEEKS OF AGE. THE OBSERVED GROWTH DEFICITS ASSOCIATED WITH INSULIN HYPERSENSITIVITY IN THE MALE OFFSPRING, WHILE IN CONTRAST, FEMALES DISPLAYED A MODEST LAG IN THEIR GLUCOSE TOLERANCE TEST. THESE METABOLIC DEFECTS WERE ASSOCIATED WITH AN UP-REGULATION OF GENES WITHIN THE PRO-FIBROTIC TGF-BETA SIGNALING PATHWAY AND INCREASED LEVELS OF CELLULAR HYDROXYPROLINE WITHIN THE LIVERS OF THE MALE OFFSPRING. WE OBSERVED SUPPRESSED CYTOKINE PROFILES WITHIN THE LIVER AND PANCREAS OF BOTH THE MALE AND FEMALE OFFSPRING, WHICH CORRELATED WITH THE UP-REGULATION OF GENES IN THE LIVERX/RETINOIDX/FARNESOIDX RECEPTOR PATHWAYS. HOWEVER, PATTERNS OF GENE EXPRESSION WERE HIGHLY VARIABLE BETWEEN THE OFFSPRING OF ALCOHOL-EXPOSED SIRES. IN THE ADULT OFFSPRING OF ALCOHOL-EXPOSED MALES, WE DID NOT OBSERVE ANY DIFFERENCES IN THE ALLELIC EXPRESSION OF IGF2 OR ANY OTHER IMPRINTED GENES. CONCLUSIONS: THE IMPACT OF PATERNAL ALCOHOL USE ON CHILD DEVELOPMENT IS POORLY EXPLORED AND REPRESENTS A SIGNIFICANT GAP IN OUR UNDERSTANDING OF THE TERATOGENIC EFFECTS OF ETHANOL. OUR STUDIES IMPLICATE PATERNAL EXPOSURE HISTORY AS AN ADDITIONAL AND IMPORTANT MODIFIER OF ALCOHOL-INDUCED GROWTH PHENOTYPES AND CHALLENGE THE CURRENT MATERNAL-CENTRIC EXPOSURE PARADIGM. 2019 10 2445 30 EPIGENETIC STATUS OF GDNF IN THE VENTRAL STRIATUM DETERMINES SUSCEPTIBILITY AND ADAPTATION TO DAILY STRESSFUL EVENTS. STRESSFUL EVENTS DURING ADULTHOOD ARE POTENT ADVERSE ENVIRONMENTAL FACTORS THAT CAN PREDISPOSE INDIVIDUALS TO PSYCHIATRIC DISORDERS, INCLUDING DEPRESSION; HOWEVER, MANY INDIVIDUALS EXPOSED TO STRESSFUL EVENTS CAN ADAPT AND FUNCTION NORMALLY. WHILE STRESS VULNERABILITY MAY INFLUENCE DEPRESSION, THE MOLECULAR MECHANISMS UNDERLYING THE SUSCEPTIBILITY AND ADAPTATION TO CHRONIC STRESS WITHIN THE BRAIN ARE POORLY UNDERSTOOD. IN THIS STUDY, TWO GENETICALLY DISTINCT MOUSE STRAINS THAT EXHIBIT DIFFERENT BEHAVIORAL RESPONSES TO CHRONIC STRESS WERE USED TO DEMONSTRATE HOW THE DIFFERENTIAL EPIGENETIC STATUS OF THE GLIAL CELL-DERIVED NEUROTROPHIC FACTOR (GDNF) GENE IN THE VENTRAL STRIATUM MODULATES SUSCEPTIBILITY AND ADAPTATION TO CHRONIC STRESS. OUR RESULTS SUGGEST THAT THE HISTONE MODIFICATIONS AND DNA METHYLATION OF THE GDNF PROMOTER HAVE CRUCIAL ROLES IN THE CONTROL OF BEHAVIORAL RESPONSES TO CHRONIC STRESS. OUR DATA PROVIDE INSIGHTS INTO THESE MECHANISMS, SUGGESTING THAT EPIGENETIC MODIFICATIONS OF GDNF, ALONG WITH GENETIC AND ENVIRONMENTAL FACTORS, CONTRIBUTE TO BEHAVIORAL RESPONSES TO STRESS. 2011 11 3973 30 LONG-TERM BEHAVIORAL AND NEUROENDOCRINE ALTERATIONS FOLLOWING CHRONIC SOCIAL STRESS IN MICE: IMPLICATIONS FOR STRESS-RELATED DISORDERS. THE PERIOD OF ADOLESCENCE IS CHARACTERIZED BY A HIGH VULNERABILITY TO STRESS AND TRAUMA, WHICH MIGHT RESULT IN LONG-LASTING CONSEQUENCES AND AN INCREASED RISK TO DEVELOP PSYCHIATRIC DISORDERS. USING A RECENTLY DEVELOPED MOUSE MODEL FOR CHRONIC SOCIAL STRESS DURING ADOLESCENCE, WE STUDIED PERSISTENT NEUROENDOCRINE AND BEHAVIORAL EFFECTS OF CHRONIC SOCIAL STRESS OBTAINED 12 MONTHS AFTER CESSATION OF THE STRESSOR. AS A REFERENCE, WE INVESTIGATED IMMEDIATE EFFECTS OF CHRONIC STRESS EXPOSURE OBTAINED AT THE END OF THE CHRONIC STRESS PERIOD. IMMEDIATELY AFTER THE 7 WEEK CHRONIC STRESS PERIOD STRESSED ANIMALS SHOW SIGNIFICANTLY INCREASED ADRENAL WEIGHTS, DECREASED THYMUS WEIGHT, INCREASED BASAL CORTICOSTERONE SECRETION AND A FLATTENED CIRCADIAN RHYTHM. FURTHERMORE, STRESSED ANIMALS DISPLAY AN INCREASED ANXIETY-LIKE BEHAVIOR IN THE ELEVATED PLUS MAZE AND THE NOVELTY-INDUCED SUPPRESSION OF FEEDING TEST. HIPPOCAMPAL MINERALOCORTICOID RECEPTOR (MR) AND THE GLUCOCORTICOID RECEPTOR (GR) MRNA LEVELS WERE SIGNIFICANTLY DECREASED. TO INVESTIGATE PERSISTENT CONSEQUENCES OF THIS EARLY STRESSFUL EXPERIENCE, THE SAME PARAMETERS WERE ASSESSED IN AGED MICE 12 MONTHS AFTER THE CESSATION OF THE STRESSOR. INTERESTINGLY, WE STILL FOUND DIFFERENCES BETWEEN FORMERLY STRESSED AND CONTROL MICE IN IMPORTANT STRESS-RELATED PARAMETERS. MR EXPRESSION LEVELS WERE SIGNIFICANTLY LOWER IN STRESSED ANIMALS, SUGGESTING LASTING, POSSIBLY EPIGENETIC ALTERATIONS IN GENE EXPRESSION REGULATION. FURTHERMORE, WE OBSERVED LONG-TERM BEHAVIORAL ALTERATIONS IN ANIMALS STRESSED DURING ADOLESCENCE. THUS, WE COULD DEMONSTRATE THAT CHRONIC STRESS EXPOSURE DURING A CRUCIAL DEVELOPMENTAL TIME PERIOD RESULTS IN LONG-TERM, PERSISTENT EFFECTS ON PHYSIOLOGICAL AND BEHAVIORAL PARAMETERS THROUGHOUT LIFE, WHICH MAY CONTRIBUTE TO AN ENHANCED VULNERABILITY TO STRESS-INDUCED DISEASES. 2008 12 5168 40 PRECONCEPTIONAL PATERNAL EXPOSURE TO A SINGLE TRAUMATIC EVENT AFFECTS POSTNATAL GROWTH OF FEMALE BUT NOT MALE OFFSPRING. ALTHOUGH PRECONCEPTIONAL AND PERICONCEPTIONAL MATERNAL STRESS IS A RECOGNIZED RISK FACTOR FOR OFFSPRING NEURODEVELOPMENTAL DISTURBANCES, LESS IS KNOWN ABOUT THE RELEVANCE OF PATERNAL EXPOSURES. THESE HAVE HITHERTO BEEN INVESTIGATED MAINLY WITH RESPECT TO SUBSTANCE-INDUCED IMPAIRMENT IN THE PROGENY. IN RECENT YEARS, EXPERIENTIAL INFLUENCES ON OFFSPRING HAVE COME INTO FOCUS THROUGH GROWING INSIGHT INTO EPIGENETIC MECHANISMS SUCH AS NONGENETIC MODES OF TRANSMISSION. THE EFFECT OF CHRONIC AND/OR EARLY MANIPULATIONS IN MALES HAS BEEN STUDIED BUT MUCH LESS IS KNOWN ABOUT THE POTENTIAL IMPACT OF SINGULAR MANIPULATIONS IN OLDER INDIVIDUALS. WE INVESTIGATED THE INFLUENCE OF A STRONG STRESSOR EXPOSURE, REMINISCENT OF A TRAUMATIC EVENT, IN ADULT MALE MICE ON OFFSPRING BEHAVIOR. MALE MICE, 6 WEEKS OF AGE, RECEIVED A STRONG FOOTSHOCK AND WERE MATED TO NAIVE FEMALES SEVERAL WEEKS LATER. MALE AND FEMALE OFFSPRING WERE INVESTIGATED IN A VARIETY OF TESTS FOR ANXIETY-LIKE AND DEPRESSION-LIKE BEHAVIORS. IN ADDITION, BODYWEIGHT DEVELOPMENT WAS ASSESSED. ALTHOUGH WE DID NOT OBSERVE ANY ALTERATIONS IN ANXIETY-LIKE AND DEPRESSIVE-LIKE BEHAVIORAL INDICES, WE RECORDED REDUCED BODYWEIGHT DEVELOPMENT IN THE FEMALE OFFSPRING. OUR DATA EMPHASIZE THE RELEVANCE OF SEX AS A (CO)DETERMINANT OF OUTCOMES IN THE WAKE OF PARENTAL MANIPULATIONS. THEY FURTHER SUGGEST THAT THE WINDOW OF VULNERABILITY FOR THE INDUCTION OF PATRILINEAR EFFECTS MIGHT BE WIDER THAN THAT CURRENTLY ASSUMED. 2013 13 990 39 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 14 4276 33 MICROGLIA FROM OFFSPRING OF DAMS WITH ALLERGIC ASTHMA EXHIBIT EPIGENOMIC ALTERATIONS IN GENES DYSREGULATED IN AUTISM. DYSREGULATION IN IMMUNE RESPONSES DURING PREGNANCY INCREASES THE RISK OF A HAVING A CHILD WITH AN AUTISM SPECTRUM DISORDER (ASD). ASTHMA IS ONE OF THE MOST COMMON CHRONIC DISEASES AMONG PREGNANT WOMEN, AND SYMPTOMS OFTEN WORSEN DURING PREGNANCY. WE RECENTLY DEVELOPED A MOUSE MODEL OF MATERNAL ALLERGIC ASTHMA (MAA) THAT INDUCES CHANGES IN SOCIABILITY, REPETITIVE, AND PERSEVERATIVE BEHAVIORS IN THE OFFSPRING. SINCE EPIGENETIC CHANGES HELP A STATIC GENOME ADAPT TO THE MATERNAL ENVIRONMENT, ACTIVATION OF THE IMMUNE SYSTEM MAY EPIGENETICALLY ALTER FETAL MICROGLIA, THE BRAIN'S RESIDENT IMMUNE CELLS. WE THEREFORE TESTED THE HYPOTHESIS THAT EPIGENOMIC ALTERATIONS TO MICROGLIA MAY BE INVOLVED IN BEHAVIORAL ABNORMALITIES OBSERVED IN MAA OFFSPRING. WE USED THE GENOME-WIDE APPROACHES OF WHOLE GENOME BISULFITE SEQUENCING TO EXAMINE DNA METHYLATION AND RNA SEQUENCING TO EXAMINE GENE EXPRESSION IN MICROGLIA FROM JUVENILE MAA OFFSPRING. DIFFERENTIALLY METHYLATED REGIONS WERE ENRICHED FOR IMMUNE SIGNALING PATHWAYS AND IMPORTANT MICROGLIAL DEVELOPMENTAL TRANSCRIPTION FACTOR BINDING MOTIFS. DIFFERENTIAL EXPRESSION ANALYSIS IDENTIFIED GENES INVOLVED IN CONTROLLING MICROGLIAL SENSITIVITY TO THE ENVIRONMENT AND SHAPING NEURONAL CONNECTIONS IN THE DEVELOPING BRAIN. DIFFERENTIALLY EXPRESSED GENES SIGNIFICANTLY OVERLAPPED GENES WITH ALTERED EXPRESSION IN HUMAN ASD CORTEX, SUPPORTING A ROLE FOR MICROGLIA IN THE PATHOGENESIS OF ASD. 2018 15 2677 33 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 16 291 31 AGING AND STRESS: PAST HYPOTHESES, PRESENT APPROACHES AND PERSPECTIVES. BRAIN AGING HAS BEEN SUGGESTED TO BE CONDITIONED BY AN EXCESSIVE GLUCOCORTIOID SECRETION LEADING TO DAMAGES ON BRAIN AREAS INVOLVED NOT ONLY IN COGNITIVE AND EMOTIONAL PROCESSES BUT ALSO IN THE CONTROL OF THE ACTIVITY OF THE HYPOTHALAMIC-PITUITARY ADRENAL AXIS. THIS REVIEW DESCRIBES SOME OF THE HYPOTHESIS THAT TRY TO EXPLAIN THE RELATION BETWEEN THE DYSREGULATION OF THE STRESS RESPONSE AND BRAIN AGING, FOCUSING ON CORTICOSTERONE BUT ALSO ON NEUROTRANSMISSION IN THE HIPPOCAMPUS, THE PREFRONTAL CORTEX AND THE AMYGDALA. MOREOVER, DIFFERENT MOLECULAR FACTORS CAN ACCOUNT FOR AN ENHANCED VULNERABILITY OF THE AGED BRAIN TO STRESS EXPOSURE, SPECIALLY FOR RESILIENCE. AMONG THEM, GOOD CANDIDATES COULD BE THOSE MECHANISMS DETERMINING THE LEVELS OF CORTICOSTERONE IN THE BRAIN, SEVERAL MOLECULES DOWNSTREAM GLUCOCORTICOID RECEPTOR ACTIVATION (IE: HEAT SHOCK PROTEINS, BAG-1) OR EVEN THE EPIGENETIC PROGRAMMING OF THE HPA AXIS IN EARLY STAGES. IN CONCLUSION, GENETIC AND ENVIRONMENTAL FACTORS (EARLY LIFE STRESS, CHRONIC STRESS DURING ADULTHOOD) CAN PRODUCE AN ENHANCED VULNERABILITY AND A REDUCED RESILIENCE OF THE BRAIN TO SUBSEQUENT STRESS EXPOSURES OR TO METABOLIC CHALLENGES LEADING, IN TURN, TO AN UNSUCCESSFUL AGING OF THE BRAIN. HOWEVER, RESULTS OBTAINED WITH THE USE OF THE ENVIRONMENTAL ENRICHMENT MODEL IN ANIMALS, ADDED TO SEVERAL RESULTS IN HUMANS ALSO DESCRIBED IN THIS REVIEW SUGGEST THAT POSITIVE ENVIRONMENTAL FACTORS (COGNITIVE-DEMANDING TASKS OR PHYSICAL EXERCISE) CAN HELP TO MAINTAIN NEURONAL PLASTICITY DURING AGING AND TO PROTECT THE BRAIN AGAINST THE DAMAGING EFFECTS OF STRESS EXPOSURE. 2011 17 1790 34 EFFECT OF CHRONIC MILD STRESS ON HIPPOCAMPAL TRANSCRIPTOME IN MICE SELECTED FOR HIGH AND LOW STRESS-INDUCED ANALGESIA AND DISPLAYING DIFFERENT EMOTIONAL BEHAVIORS. THERE IS INCREASING EVIDENCE THAT MOOD DISORDERS MAY DERIVE FROM THE IMPACT OF ENVIRONMENTAL PRESSURE ON GENETICALLY SUSCEPTIBLE INDIVIDUALS. STRESS-INDUCED HIPPOCAMPAL PLASTICITY HAS BEEN IMPLICATED IN DEPRESSION. WE STUDIED HIPPOCAMPAL TRANSCRIPTOMES IN STRAINS OF MICE THAT DISPLAY HIGH (HA) AND LOW (LA) SWIM STRESS-INDUCED ANALGESIA AND THAT DIFFER IN EMOTIONAL BEHAVIORS AND RESPONSES TO DIFFERENT CLASSES OF ANTIDEPRESSANTS. CHRONIC MILD STRESS (CMS) AFFECTED EXPRESSION OF A NUMBER OF GENES COMMON FOR BOTH STRAINS. CMS ALSO PRODUCED STRAIN SPECIFIC CHANGES IN EXPRESSION SUGGESTING THAT HIPPOCAMPAL RESPONSES TO STRESS DEPEND ON GENOTYPE. CONSIDERABLY LARGER NUMBER OF GENES, BIOLOGICAL PROCESSES, MOLECULAR FUNCTIONS, BIOCHEMICAL PATHWAYS, AND GENE NETWORKS WERE AFFECTED BY CMS IN LA THAN IN HA MICE. THE RESULTS SUGGEST THAT POTENTIAL DRUG TARGETS AGAINST DETRIMENTAL EFFECTS OF STRESS INCLUDE GLUTAMATE TRANSPORTERS, AND CHOLINERGIC, CHOLECYSTOKININ (CCK), GLUCOCORTICOIDS, AND THYROID HORMONES RECEPTORS. FURTHERMORE, SOME BIOLOGICAL PROCESSES EVOKED BY STRESS AND DIFFERENT BETWEEN THE STRAINS, SUCH AS APOPTOSIS, NEUROGENESIS AND CHROMATIN MODIFICATIONS, MAY BE RESPONSIBLE FOR THE LONG-TERM, IRREVERSIBLE EFFECTS OF STRESS AND SUGGEST A ROLE FOR EPIGENETIC REGULATION OF MOOD RELATED STRESS RESPONSES. 2011 18 5645 34 SEX DEPENDENT ALTERATION OF EPIGENETIC MARKS AFTER CHRONIC MORPHINE TREATMENT IN MICE ORGANS. EPIGENETIC MARKS MAY BE ALSO AFFECTED BY SEVERAL FACTORS, SUCH AS AGE, LIFESTYLE, EARLY LIFE EXPERIENCES AND EXPOSURE TO CHEMICALS OR DRUGS, SUCH AS OPIOIDS. PREVIOUS STUDIES HAVE FOCUSED ON HOW MORPHINE EPIGENETICALLY REGULATES DIFFERENT REGIONS OF THE BRAIN THAT ARE IMPLICATED IN TOLERANCE, DEPENDENCE AND OTHER PSYCHIATRIC DISORDERS MORE RELATED TO THE PHYSIO-PATHOLOGICAL EFFECTS OF OPIOIDS. NEVERTHELESS, A SIGNIFICANT KNOWLEDGE GAP REMAINS REGARDING THE EFFECT OF CHRONIC TREATMENT ON OTHER ORGANS AND BIOLOGICAL SYSTEMS. THEREFORE, THE AIM OF THIS WORK IS TO INCREASE OUR KNOWLEDGE ABOUT THE IMPACT OF CHRONIC MORPHINE EXPOSURE ON DNA METHYLATION AND HISTONE MODIFICATION LEVELS IN EACH OF THE ORGANS OF MALE AND FEMALE MODEL MICE IN VIVO. OUR RESULTS REVEAL, FOR THE FIRST TIME, THAT CHRONIC MORPHINE TREATMENT INDUCED CHANGES IN DNA METHYLATION/HYDROXYMETHYLATION AND HISTONE MODIFICATION IN-VIVO AT THE SYSTEMIC LEVEL, REVEALING A POTENTIAL PHYSIOLOGICAL EFFECT ON THE REGULATION OF GENE EXPRESSION. NOTABLY, MORPHINE-INDUCED EPIGENETIC MODIFICATION OCCURS IN A SEX-DEPENDENT MANNER, REVEALING THE EXISTENCE OF DIFFERENT UNDERLYING MECHANISMS OF EPIGENETIC MODIFICATION IN MALE AND FEMALE MICE. 2021 19 1765 37 EARLY-LIFE ADVERSITY-INDUCED LONG-TERM EPIGENETIC PROGRAMMING ASSOCIATED WITH EARLY ONSET OF CHRONIC PHYSICAL AGGRESSION: STUDIES IN HUMANS AND ANIMALS. OBJECTIVES: TO EXAMINE WHETHER CHRONIC PHYSICAL AGGRESSION (CPA) IN ADULTHOOD CAN BE EPIGENETICALLY PROGRAMMED EARLY IN LIFE DUE TO EXPOSURE TO EARLY-LIFE ADVERSITY. METHODS: LITERATURE SEARCH OF PUBLIC DATABASES SUCH AS PUBMED/MEDLINE AND SCOPUS. RESULTS: CHILDREN/ADOLESCENTS SUSCEPTIBLE FOR CPA AND EXPOSED TO EARLY-LIFE ABUSE FAIL TO EFFICIENTLY COPE WITH STRESS THAT IN TURN RESULTS IN THE DEVELOPMENT OF CPA LATER IN LIFE. THIS PHENOMENON WAS OBSERVED IN HUMANS AND ANIMAL MODELS OF AGGRESSION. THE SUSCEPTIBILITY TO AGGRESSION IS A COMPLEX TRAIT THAT IS REGULATED BY THE INTERACTION BETWEEN ENVIRONMENTAL AND GENETIC FACTORS. EPIGENETIC MECHANISMS MEDIATE THIS INTERACTION. SUBJECTS EXPOSED TO STRESS EARLY IN LIFE EXHIBITED LONG-TERM EPIGENETIC PROGRAMMING THAT CAN INFLUENCE THEIR BEHAVIOUR IN ADULTHOOD. THIS PROGRAMMING AFFECTS EXPRESSION OF MANY GENES NOT ONLY IN THE BRAIN BUT ALSO IN OTHER SYSTEMS SUCH AS NEUROENDOCRINE AND IMMUNE. CONCLUSIONS: THE PROPENSITY TO ADULT CPA BEHAVIOUR IN SUBJECTS EXPERIENCED TO EARLY-LIFE ADVERSITY IS MEDIATED BY EPIGENETIC PROGRAMMING THAT INVOLVES LONG-TERM SYSTEMIC EPIGENETIC ALTERATIONS IN A WHOLE GENOME. 2019 20 4064 33 MATERNAL AND EARLY-LIFE CIRCADIAN DISRUPTION HAVE LONG-LASTING NEGATIVE CONSEQUENCES ON OFFSPRING DEVELOPMENT AND ADULT BEHAVIOR IN MICE. MODERN LIFE INVOLVES CHRONIC CIRCADIAN DISRUPTION THROUGH ARTIFICIAL LIGHT AND THESE DISRUPTIONS ARE ASSOCIATED WITH NUMEROUS MENTAL AND PHYSICAL HEALTH MALADIES. BECAUSE THE DEVELOPING NERVOUS SYSTEM IS PARTICULARLY VULNERABLE TO PERTURBATION, WE HYPOTHESIZED THAT EARLY-LIFE CIRCADIAN DISRUPTION WOULD NEGATIVELY IMPACT OFFSPRING DEVELOPMENT AND ADULT FUNCTION. PREGNANT MICE WERE SUBJECTED TO CHRONIC CIRCADIAN DISRUPTION FROM THE TIME OF UTERINE IMPLANTATION THROUGH WEANING. TO DISSOCIATE IN UTERO FROM POSTNATAL EFFECTS, A SUBSET OF LITTERS WAS CROSS-FOSTERED AT BIRTH FROM DISRUPTED DAMS TO CONTROL DAMS AND VICE VERSA. POSTNATAL CIRCADIAN DISRUPTION WAS ASSOCIATED WITH REDUCED ADULT BODY MASS, SOCIAL AVOIDANCE, AND HYPERACTIVITY. IN UTERO DISRUPTION RESULTED IN MORE PRONOUNCED SOCIAL AVOIDANCE AND HYPERACTIVITY, PHENOTYPES NOT ABROGATED BY CROSS-FOSTERING TO CONTROL MOTHERS. TO EXAMINE WHETHER CIRCADIAN DISRUPTION AFFECTS DEVELOPMENT BY ACTING AS AN EARLY LIFE STRESSOR, WE EXAMINED BIRTHWEIGHT, LITTER SIZE, MATERNAL CANNIBALISM, AND EPIGENETIC MODIFICATIONS. NONE OF THESE VARIABLES DIFFERED BETWEEN CONTROL AND DISRUPTED DAMS, OR RESEMBLED PATTERNS SEEN FOLLOWING EARLY-LIFE STRESS. OUR FINDINGS INDICATE THAT DEVELOPMENTAL CHRONIC CIRCADIAN DISRUPTION PERMANENTLY AFFECTS SOMATIC AND BEHAVIORAL DEVELOPMENT IN A STAGE-OF-LIFE-DEPENDENT MANNER, INDEPENDENT OF EARLY LIFE STRESS MECHANISMS, UNDERSCORING THE IMPORTANCE OF TEMPORAL STRUCTURE DURING DEVELOPMENT, BOTH IN UTERO AND EARLY POSTNATAL LIFE. 2017