1 2123 173 EPIGENETIC IMPACTS OF STRESS PRIMING OF THE NEUROINFLAMMATORY RESPONSE TO SARIN SURROGATE IN MICE: A MODEL OF GULF WAR ILLNESS. BACKGROUND: GULF WAR ILLNESS (GWI) IS AN ARCHETYPAL, MEDICALLY UNEXPLAINED, CHRONIC CONDITION CHARACTERISED BY PERSISTENT SICKNESS BEHAVIOUR AND NEUROIMMUNE AND NEUROINFLAMMATORY COMPONENTS. AN ESTIMATED 25-32% OF THE OVER 900,000 VETERANS OF THE 1991 GULF WAR FULFIL THE REQUIREMENTS OF A GWI DIAGNOSIS. IT HAS BEEN HYPOTHESISED THAT THE HIGH PHYSICAL AND PSYCHOLOGICAL STRESS OF COMBAT MAY HAVE INCREASED VULNERABILITY TO IRREVERSIBLE ACETYLCHOLINESTERASE (ACHE) INHIBITORS LEADING TO A PRIMING OF THE NEUROIMMUNE SYSTEM. A NUMBER OF STUDIES HAVE LINKED HIGH LEVELS OF PSYCHOPHYSIOLOGICAL STRESS AND TOXICANT EXPOSURES TO EPIGENETIC MODIFICATIONS THAT REGULATE GENE EXPRESSION. RECENT RESEARCH IN A MOUSE MODEL OF GWI HAS SHOWN THAT PRE-EXPOSURE WITH THE STRESS HORMONE CORTICOSTERONE (CORT) CAUSES AN INCREASE IN EXPRESSION OF SPECIFIC CHEMOKINES AND CYTOKINES IN RESPONSE TO DIISOPROPYL FLUOROPHOSPHATE (DFP), A SARIN SURROGATE AND IRREVERSIBLE ACHE INHIBITOR. METHODS: C57BL/6J MICE WERE EXPOSED TO CORT FOR 4 DAYS, AND EXPOSED TO DFP ON DAY 5, BEFORE SACRIFICE 6 H LATER. THE TRANSCRIPTOME WAS EXAMINED USING RNA-SEQ, AND THE EPIGENOME WAS EXAMINED USING REDUCED REPRESENTATION BISULFITE SEQUENCING AND H3K27AC CHIP-SEQ. RESULTS: WE SHOW TRANSCRIPTIONAL, HISTONE MODIFICATION (H3K27AC) AND DNA METHYLATION CHANGES IN GENES RELATED TO THE IMMUNE AND NEURONAL SYSTEM, POTENTIALLY RELEVANT TO NEUROINFLAMMATORY AND COGNITIVE SYMPTOMS OF GWI. FURTHER EVIDENCE SUGGESTS ALTERED PROPORTIONS OF MYELINATING OLIGODENDROCYTES IN THE FRONTAL CORTEX, PERHAPS CONNECTED TO WHITE MATTER DEFICITS SEEN IN GWI SUFFERERS. CONCLUSIONS: OUR FINDINGS MAY REFLECT THE EARLY CHANGES WHICH OCCURRED IN GWI VETERANS, AND WE OBSERVE ALTERATIONS IN SEVERAL PATHWAYS ALTERED IN GWI SUFFERERS. THESE CLOSE LINKS TO CHANGES SEEN IN VETERANS WITH GWI INDICATES THAT THIS MODEL REFLECTS THE ENVIRONMENTAL EXPOSURES RELATED TO GWI AND MAY PROVIDE A MODEL FOR BIOMARKER DEVELOPMENT AND TESTING FUTURE TREATMENTS. 2018 2 1988 50 EPIGENETIC ANALYSIS IN A MURINE GENETIC MODEL OF GULF WAR ILLNESS. OF THE NEARLY 1 MILLION MILITARY PERSONNEL WHO PARTICIPATED IN THE 1990-1991 GULF WAR, BETWEEN 25% AND 35% BECAME ILL WITH WHAT NOW IS REFERRED TO AS GULF WAR ILLNESS (GWI) BY THE DEPARTMENT OF DEFENSE. SYMPTOMS VARIED FROM GASTROINTESTINAL DISTRESS TO LETHARGY, MEMORY LOSS, INABILITY TO CONCENTRATE, DEPRESSION, RESPIRATORY, AND REPRODUCTIVE PROBLEMS. THE SYMPTOMS HAVE PERSISTED FOR 30 YEARS IN THOSE AFFLICTED BUT THE BASIS OF THE ILLNESS REMAINS LARGELY UNKNOWN. NERVE AGENTS AND OTHER CHEMICAL EXPOSURES IN THE WAR ZONE HAVE BEEN IMPLICATED BUT THE LONG-TERM EFFECTS OF THESE ACUTE EXPOSURES HAVE LEFT FEW IF ANY IDENTIFIABLE SIGNATURES. THE MAJOR AIM OF THIS STUDY IS TO ELUCIDATE THE POSSIBLE GENOMIC BASIS FOR THE PERSISTENCE OF SYMPTOMS, ESPECIALLY OF THE NEUROLOGICAL AND BEHAVIORAL EFFECTS. TO ADDRESS THIS, WE PERFORMED A WHOLE GENOME EPIGENETIC ANALYSIS OF THE PROPOSED CAUSE OF GWI, VIZ., EXPOSURE TO ORGANOPHOSPHATE NEUROTOXICANTS COMBINED WITH HIGH CIRCULATING GLUCOCORTICOIDS IN TWO INBRED MOUSE STRAINS, C57BL/6J AND DBA/2J. THE ANIMALS RECEIVED CORTICOSTERONE IN THEIR DRINKING WATER FOR 7 DAYS FOLLOWED BY INJECTION OF DIISOPROPYLFLUOROPHOSPHATE, A NERVE AGENT SURROGATE. SIX WEEKS AFTER DFP INJECTION, THE ANIMALS WERE EUTHANIZED AND MEDIAL PREFRONTAL CORTEX HARVESTED FOR GENOME-WIDE DNA METHYLATION ANALYSIS USING HIGH-THROUGHPUT SEQUENCING. WE OBSERVED 67 DIFFERENTIALLY METHYLATED GENES, NOTABLY AMONG THEM, TTLL7, AKR1C14, SLC44A4, AND RUSC2, ALL RELATED TO DIFFERENT SYMPTOMS OF GWI. OUR RESULTS SUPPORT PROOF OF PRINCIPLE OF GENETIC DIFFERENCES IN THE CHRONIC EFFECTS OF GWI-RELATED EXPOSURES AND MAY REVEAL WHY THE DISEASE HAS PERSISTED IN MANY OF THE NOW AGING GULF WAR VETERANS. 2023 3 336 42 ALTERATIONS IN DNA METHYLATION STATUS ASSOCIATED WITH GULF WAR ILLNESS. GULF WAR ILLNESS (GWI) AFFECTS ABOUT 25% OF PERSIAN GULF VETERANS WITH A CLUSTER OF CHRONIC SYMPTOMS, INCLUDING IMMUNE DYSFUNCTION AND NEUROLOGICAL ISSUES. RECENT STUDIES IMPLICATE GENE EXPRESSION CHANGES IN IMMUNE FUNCTION TO BE ASSOCIATED WITH GWI. SINCE DNA METHYLATION CAN REGULATE SUCH CHANGES IN GENE EXPRESSION, AND DISRUPTION OF DNA METHYLATION PATTERN IS IMPLICATED IN VARIOUS IMMUNE AND NEUROLOGICAL DISEASES, WE AIMED TO STUDY THE DNA METHYLATION PATTERNS IN PERIPHERAL BLOOD MONONUCLEAR CELLS FROM GWI PATIENTS. GLOBAL DNA METHYLATION LEVELS WERE SIMILAR IN GWI PATIENTS AND CONTROLS. HOWEVER, THE GENOME-WIDE MICROARRAY TECHNOLOGY DETECTED 10,767 DIFFERENTIALLY METHYLATED CPG SITES ACROSS GENE REGULATORY ELEMENTS AND WITHIN CODING REGIONS. APPROXIMATELY 88% OF THEM WERE HYPERMETHYLATED IN GWI PATIENTS. THE SEPARATE ANALYSIS FOUND 776 DIFFERENTIALLY METHYLATED GENE PROMOTERS (DMP), WHICH WERE PREDOMINANTLY HYPERMETHYLATED. PYROSEQUENCING VALIDATION CONFIRMED MICROARRAY RESULTS. FUNCTIONAL ANALYSIS REVEALED THAT MAJORITY OF THE DMPS BELONGED TO GENES RESPONSIBLE FOR METABOLISM AND IMMUNE SYSTEM. THIS IS THE FIRST PILOT HUMAN STUDY CHARACTERIZING GENOME-WIDE EPIGENETIC CHANGES ASSOCIATED WITH GWI. IT SUGGESTS A SIGNIFICANT CONTRIBUTION OF EPIGENETIC DYSFUNCTION IN GWI. MOREOVER, IT SUPPORTS THE DYSREGULATION OF IMMUNE FUNCTION IN GWI. LASTLY, IT SUGGESTS STUDIES WITH THE LARGER COHORT TO VALIDATE OUR FINDINGS. 2019 4 5451 40 REPROGRAMMING CELLS FROM GULF WAR VETERANS INTO NEURONS TO STUDY GULF WAR ILLNESS. GULF WAR ILLNESS (GWI), WHICH AFFLICTS AT LEAST 25% OF VETERANS WHO SERVED IN THE 1990-1991 WAR IN THE PERSIAN GULF, IS THOUGHT TO BE CAUSED BY DEPLOYMENT EXPOSURES TO VARIOUS NEUROTOXICANTS, INCLUDING PESTICIDES, ANTI-NERVE GAS PILLS, AND LOW-LEVEL NERVE AGENTS INCLUDING SARIN/CYCLOSARIN. GWI IS A MULTISYMPTOM DISORDER CHARACTERIZED BY FATIGUE, JOINT PAIN, COGNITIVE PROBLEMS, AND GASTROINTESTINAL COMPLAINTS. THE MOST PROMINENT SYMPTOMS OF GWI (MEMORY PROBLEMS, POOR ATTENTION/CONCENTRATION, CHRONIC HEADACHES, MOOD ALTERATIONS, AND IMPAIRED SLEEP) SUGGEST THAT THE DISEASE PRIMARILY AFFECTS THE CNS. DEVELOPMENT OF URGENTLY NEEDED TREATMENTS DEPENDS ON EXPERIMENTAL MODELS APPROPRIATE FOR TESTING MECHANISTIC HYPOTHESES AND FOR SCREENING THERAPEUTIC COMPOUNDS. RODENT MODELS HAVE BEEN USEFUL THUS FAR, BUT ARE LIMITED BY THEIR INABILITY TO ASSESS THE CONTRIBUTION OF GENETIC OR EPIGENETIC BACKGROUND TO THE DISEASE, AND BECAUSE DISEASE-VULNERABLE PROTEINS AND PATHWAYS MAY BE DIFFERENT IN HUMANS RELATIVE TO RODENTS. AS OF YET, NO POSTMORTEM TISSUE FROM THE VETERANS HAS BECOME AVAILABLE FOR RESEARCH. WE ARE MOVING FORWARD WITH A PARADIGM SHIFT IN THE STUDY OF GWI, WHICH UTILIZES CONTEMPORARY STEM CELL TECHNOLOGY TO CONVERT SOMATIC CELLS FROM GULF WAR VETERANS INTO PLURIPOTENT CELL LINES THAT CAN BE DIFFERENTIATED INTO VARIOUS CELL TYPES, INCLUDING NEURONS, GLIA, MUSCLE, OR OTHER RELEVANT CELL TYPES. SUCH CELL LINES ARE IMMORTAL AND WILL BE A RESOURCE FOR GWI RESEARCHERS TO PURSUE MECHANISTIC HYPOTHESES AND THERAPEUTICS. 2017 5 3980 48 LONG-TERM EPIGENETIC ALTERATIONS IN A RAT MODEL OF GULF WAR ILLNESS. GULF WAR ILLNESS (GWI) IS A CHRONIC, MULTISYMPTOM ILLNESS THAT AFFECTS 25% OF THE 700,000 US VETERANS DEPLOYED TO THE PERSIAN GULF DURING THE 1990-1991 GULF WAR. CENTRAL NERVOUS SYSTEM IMPAIRMENTS ARE AMONG THE MOST COMMON SYMPTOMS REPORTED, INCLUDING MEMORY DYSFUNCTION AND DEPRESSION. AFTER 25 YEARS, THE DIAGNOSIS REMAINS ELUSIVE, USEFUL TREATMENTS ARE LACKING, AND THE CAUSE IS POORLY UNDERSTOOD, ALTHOUGH EXPOSURES TO PYRIDOSTIGMINE BROMIDE (PB) AND PESTICIDES ARE CONSISTENTLY IDENTIFIED TO BE AMONG THE STRONGEST RISK FACTORS. EPIGENETIC CHANGES INCLUDING ALTERED MICRORNA (MIRNA) EXPRESSION AND DNA METHYLATION PLAY AN IMPORTANT ROLE IN LEARNING, MEMORY, AND EMOTION REGULATION AND HAVE BEEN IMPLICATED IN VARIOUS NEUROLOGICAL DISORDERS. IN THIS STUDY, WE USED AN ESTABLISHED RAT MODEL OF GWI TO DETERMINE WHETHER 1) CHRONIC ALTERATIONS IN MIRNA EXPRESSION AND GLOBAL DNA METHYLATION AND DNA HYDROXYMETHYLATION ARE MECHANISMS INVOLVED IN THE PATHOBIOLOGY OF GWI, AND 2) PLASMA EXOSOME SMALL RNAS MAY SERVE AS POTENTIAL NONINVASIVE BIOMARKERS OF THIS DEBILITATING DISEASE. ONE YEAR AFTER A 28-DAY EXPOSURE REGIMEN OF PB, DEET (N,N-DIETHYL-3-METHYLBENZAMIDE), PERMETHRIN, AND MILD STRESS, EXPRESSION OF 84 MATURE MIRNAS AND GLOBAL 5-METHYLCYTOSINE (5MC) AND 5-HYDROXYMETHYLCYTOSINE (5HMC) CONTENT WERE ANALYZED IN THE BRAINS OF GWI RATS AND VEHICLE CONTROLS BY PCR ARRAY AND ENZYME-LINKED IMMUNOSORBENT ASSAY, RESPECTIVELY. PLASMA EXOSOME RNA NEXT-GENERATION SEQUENCING ANALYSIS WAS PERFORMED IN POOLED SAMPLES TO DISCOVER POTENTIAL NONINVASIVE BIOMARKERS. WE FOUND THAT COMBINED EXPOSURE TO LOW DOSES OF GW-RELATED CHEMICALS AND MILD STRESS CAUSED EPIGENETIC MODIFICATIONS IN THE BRAIN THAT PERSISTED ONE YEAR AFTER EXPOSURE, INCLUDING INCREASED EXPRESSION OF MIR-124-3P AND MIR-29B-3P IN THE HIPPOCAMPUS AND REGIONAL ALTERATIONS IN GLOBAL 5MC AND 5HMC CONTENT. GW-RELEVANT EXPOSURES ALSO INDUCED THE DIFFERENTIAL EXPRESSION OF TWO PIWI-INTERACTING RNAS (PIRNAS) IN CIRCULATION (PIR-007899 AND PIR-019162). RESULTS FROM THIS STUDY IMPLICATE A ROLE FOR EPIGENETIC ALTERATIONS IN GWI. EVALUATION OF THE DIAGNOSTIC POTENTIAL OF PLASMA EXOSOME RNAS IN VETERANS WITH GWI IS WARRANTED. 2016 6 107 46 A REVIEW OF PRE-CLINICAL MODELS FOR GULF WAR ILLNESS. GULF WAR ILLNESS (GWI) IS A CHRONIC MULTISYMPTOMATIC DISORDER THAT AFFLICTS OVER 1/3RD OF THE 1991 GW VETERANS. IT SPANS MULTIPLE BODILY SYSTEMS AND PRESENTS ITSELF AS A SYNDROME EXHIBITING DIVERSE SYMPTOMS INCLUDING FATIGUE, DEPRESSION, MOOD, AND MEMORY AND CONCENTRATION DEFICITS, MUSCULOSKELETAL PAIN AND GASTROINTESTINAL DISTRESS IN GW VETERANS. THE ETIOLOGY OF GWI IS COMPLEX AND MANY FACTORS, INCLUDING CHEMICAL, PHYSIOLOGICAL, AND ENVIRONMENTAL STRESSORS PRESENT IN THE GW ARENA, HAVE BEEN IMPLICATED FOR ITS DEVELOPMENT. IT HAS BEEN OVER 30 YEARS SINCE THE END OF THE GW BUT, GWI HAS BEEN PERSISTENT IN SUFFERING VETERANS WHO ARE ALSO DEALING WITH PAUCITY OF EFFECTIVE TREATMENTS. THE MULTIFACTORIAL ASPECT OF GWI ALONG WITH GENETIC HETEROGENEITY AND LACK OF AVAILABLE DATA SURROUNDING WAR-TIME EXPOSURES HAVE PROVED TO BE CHALLENGING IN DEVELOPING PRE-CLINICAL MODELS OF GWI. DESPITE THIS, OVER A DOZEN GWI ANIMAL MODELS EXIST IN THE LITERATURE. IN THIS ARTICLE, FOLLOWING A BRIEF DISCUSSION OF GW HISTORY, GWI DEFINITIONS, AND PROBABLE CAUSES FOR ITS PATHOGENESIS, WE WILL EXPAND UPON VARIOUS EXPERIMENTAL MODELS USED IN GWI LABORATORY RESEARCH. THESE ANIMAL MODELS WILL BE DISCUSSED IN THE CONTEXT OF THEIR ATTEMPTS AT MIMICKING GW-RELATED EXPOSURES WITH REGARDS TO THE VARIATIONS IN CHEMICAL COMBINATIONS, DOSES, AND FREQUENCY OF EXPOSURES. WE WILL DISCUSS THEIR ADVANTAGES AND LIMITATIONS IN MODELING GWI FOLLOWED BY A DISCUSSION OF BEHAVIORAL AND MOLECULAR FINDINGS IN THESE MODELS. THE MECHANISTIC DATA OBTAINED FROM THESE PRECLINICAL STUDIES HAVE OFFERED MULTIPLE MOLECULAR PATHWAYS INCLUDING CHRONIC INFLAMMATION, MITOCHONDRIAL DYSFUNCTION, OXIDATIVE STRESS, LIPID DISTURBANCES, CALCIUM HOMEOSTATIC ALTERATIONS, CHANGES IN GUT MICROBIOTA, AND EPIGENETIC MODIFICATIONS, AMONGST OTHERS FOR EXPLAINING GWI DEVELOPMENT AND ITS PERSISTENCE. FINALLY, THESE FINDINGS HAVE ALSO INFORMED US ON NOVEL DRUGGABLE TARGETS IN GWI. WHILE, IT HAS BEEN DIFFICULT TO CONCEIVE A SINGLE PRE-CLINICAL MODEL THAT COULD EXPRESS ALL THE GWI SIGNS AND EXHIBIT BIOLOGICAL COMPLEXITY REFLECTIVE OF THE CLINICAL PRESENTATION IN GWI, ANIMAL MODELS HAVE BEEN CRITICAL FOR IDENTIFYING MOLECULAR UNDERPINNINGS OF GWI AND EVALUATING TREATMENT STRATEGIES FOR GWI. 2021 7 90 55 A PILOT REVERSE VIRTUAL SCREENING STUDY SUGGESTS TOXIC EXPOSURES CAUSED LONG-TERM EPIGENETIC CHANGES IN GULF WAR ILLNESS. GULF WAR ILLNESS (GWI) IS A CHRONIC ILLNESS THAT AFFECTS UPWARD OF 32% OF DEPLOYED VETERANS TO THE 1991 GULF WAR (GW). THE SYMPTOMS ARE MEDICALLY UNEXPLAINED, RANGING ACROSS COGNITIVE DEFICITS, FATIGUE, GASTROINTESTINAL PROBLEMS, AND MUSCULOSKELETAL PAIN. RESEARCH INDICATES THAT CHEMICAL WARFARE AGENTS PLAY A KEY ROLE IN THE ONSET AND PROGRESSION OF GWI. THE KHAMISIYAH AMMUNITION STORAGE THAT HOUSED CHEMICAL WARFARE AGENTS SUCH AS SARIN, AN ACETYLCHOLINESTERASE (ACHE) INHIBITOR, WAS DEMOLISHED DURING THE GW, RELEASING TOXICANTS INTO THE ATMOSPHERE AFFECTING DEPLOYED TROOPS. EXPOSURE TO OTHER CHEMICAL AGENTS SUCH AS PYRIDOSTIGMINE BROMIDE, N,N-DIETHYL-M-TOLUAMIDE, PERMETHRIN AND CHLORPYRIFOS, WERE ALSO PREVALENT DURING THE WAR. THESE ADDITIONAL CHEMICAL AGENTS HAVE ALSO BEEN SHOWN TO INHIBIT ACHE. ACHE INHIBITION INDUCES AN ACETYLCHOLINE BUILD-UP, DISRUPTING SIGNALS BETWEEN NERVES AND MUSCLES, WHICH IN HIGH DOSES LEADS TO ASPHYXIATION. LITTLE IS KNOWN ABOUT LOW DOSE EXPOSURE. AS BIOACTIVE COMPOUNDS TEND TO INTERACT WITH MULTIPLE PROTEINS WITH VARIOUS PHYSIOLOGICAL EFFECT, WE AIMED TO IDENTIFY OTHER POTENTIAL SHARED TARGETS TO UNDERSTAND THE EXTENT IN WHICH THESE CHEMICALS COULD LEAD TO GWI. WE FOLLOWED A REVERSE SCREENING APPROACH WHERE EACH CHEMICAL IS COMPUTATIONALLY DOCKED TO A LIBRARY OF PROTEIN TARGETS. THE PROGRAMS PHARMMAPPER AND TARGETNET WERE USED FOR THIS PURPOSE, AND FURTHER ANALYSES WERE CONDUCTED TO MARK SIGNIFICANT CHANGES IN PARTICIPANTS WITH GWI. PREVIOUSLY PUBLISHED WORK ON DNA METHYLATION STATUS IN GWI WAS REANALYZED FOCUSING SPECIFICALLY ON THE PREDICTED SHARED TARGETS INDICATING SIGNIFICANT CHANGES IN DNA METHYLATION OF THE ASSOCIATED GENES. OUR FINDINGS THUS SUGGEST THAT EXPOSURE TO GWI-RELATED AGENTS MAY CONVERGE ON SIMILAR TARGETS WITH ROLES IN INFLAMMATION, NEUROTRANSMITTER AND LIPID METABOLISM, AND DETOXIFICATION WHICH MAY HAVE IMPACTS ON NEURODEGENERATIVE-LIKE DISEASE AND OXIDATIVE STRESS IN VETERANS WITH GWI. 2022 8 990 44 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 9 2021 31 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 10 1790 41 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 11 2472 43 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 12 948 31 CHRONIC METABOLIC DERANGEMENT-INDUCED COGNITIVE DEFICITS AND NEUROTOXICITY ARE ASSOCIATED WITH REST INACTIVATION. CHRONIC METABOLIC ALTERATIONS MAY REPRESENT A RISK FACTOR FOR THE DEVELOPMENT OF COGNITIVE IMPAIRMENT, DEMENTIA, OR NEURODEGENERATIVE DISEASES. HYPERGLYCEMIA AND OBESITY ARE KNOWN TO IMPRINT EPIGENETIC MARKERS THAT COMPROMISE THE PROPER EXPRESSION OF CELL SURVIVAL GENES. HERE, WE SHOWED THAT CHRONIC HYPERGLYCEMIA (60 DAYS) INDUCED BY A SINGLE INTRAPERITONEAL INJECTION OF STREPTOZOTOCIN COMPROMISED COGNITION BY REDUCING HIPPOCAMPAL ERK SIGNALING AND BY INDUCING NEUROTOXICITY IN RATS. THE MECHANISMS APPEAR TO BE LINKED TO REDUCED ACTIVE DNA DEMETHYLATION AND DIMINISHED EXPRESSION OF THE NEUROPROTECTIVE TRANSCRIPTION FACTOR REST. THE IMPACT OF THE RELATIONSHIP BETWEEN ADIPOSITY AND DNA HYPERMETHYLATION ON REST EXPRESSION WAS ALSO DEMONSTRATED IN PERIPHERAL BLOOD MONONUCLEAR CELLS IN OBESE CHILDREN WITH REDUCED LEVELS OF BLOOD ASCORBATE. THE REVERSIBLE NATURE OF EPIGENETIC MODIFICATIONS AND THE COGNITIVE IMPAIRMENT REPORTED IN OBESE CHILDREN, ADOLESCENTS, AND ADULTS SUGGEST THAT THE CORRECTION OF THE ANTHROPOMETRY AND THE PERIPHERAL METABOLIC ALTERATIONS WOULD PROTECT BRAIN HOMEOSTASIS AND REDUCE THE RISK OF DEVELOPING NEURODEGENERATIVE DISEASES. 2019 13 3973 43 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 14 6174 46 THE HIPPOCAMPUS, NEUROTROPHIC FACTORS AND DEPRESSION: POSSIBLE IMPLICATIONS FOR THE PHARMACOTHERAPY OF DEPRESSION. DEPRESSION IS A PREVALENT, HIGHLY DEBILITATING MENTAL DISORDER AFFECTING UP TO 15% OF THE POPULATION AT LEAST ONCE IN THEIR LIFETIME, WITH HUGE COSTS FOR SOCIETY. NEUROBIOLOGICAL MECHANISMS OF DEPRESSION ARE STILL NOT WELL KNOWN, ALTHOUGH THERE IS CONSENSUS ABOUT INTERPLAY BETWEEN GENETIC AND ENVIRONMENTAL FACTORS. ANTIDEPRESSANT MEDICATIONS ARE FREQUENTLY USED IN DEPRESSION, BUT AT LEAST 50% OF PATIENTS ARE POOR RESPONDERS, EVEN TO MORE RECENTLY DISCOVERED MEDICATIONS. FURTHERMORE, CLINICAL RESPONSE ONLY OCCURS FOLLOWING WEEKS TO MONTHS OF TREATMENT AND ONLY CHRONIC TREATMENT IS EFFECTIVE, SUGGESTING THAT ACTIONS BEYOND THE RAPIDLY OCCURRING EFFECT OF ENHANCING MONOAMINERGIC SYSTEMS, SUCH AS ADAPTATION OF THESE SYSTEMS, ARE RESPONSIBLE FOR THE EFFECTS OF ANTIDEPRESSANTS. RECENT STUDIES INDICATE THAT AN IMPAIRMENT OF SYNAPTIC PLASTICITY (NEUROGENESIS, AXON BRANCHING, DENDRITOGENESIS AND SYNAPTOGENESIS) IN SPECIFIC AREAS OF THE CNS, PARTICULARLY THE HIPPOCAMPUS, MAY BE A CORE FACTOR IN THE PATHOPHYSIOLOGY OF DEPRESSION. THE ABNORMAL NEURAL PLASTICITY MAY BE RELATED TO ALTERATIONS IN THE LEVELS OF NEUROTROPHIC FACTORS, NAMELY BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF), WHICH PLAY A CENTRAL ROLE IN PLASTICITY. AS BDNF IS REPRESSED BY STRESS, EPIGENETIC REGULATION OF THE BDNF GENE MAY PLAY AN IMPORTANT ROLE IN DEPRESSION. THE HIPPOCAMPUS IS SMALLER IN DEPRESSED PATIENTS, ALTHOUGH IT IS UNCLEAR WHETHER SMALLER SIZE IS A CONSEQUENCE OF DEPRESSION OR A PRE-EXISTING, VULNERABILITY MARKER FOR DEPRESSION. ENVIRONMENTAL STRESSORS TRIGGERING ACTIVATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS CAUSE THE BRAIN TO BE EXPOSED TO CORTICOSTEROIDS, AFFECTING NEUROBEHAVIOURAL FUNCTIONS WITH A STRONG DOWNREGULATION OF HIPPOCAMPAL NEUROGENESIS, AND ARE A MAJOR RISK FACTOR FOR DEPRESSION. ANTIDEPRESSANT TREATMENT INCREASES BDNF LEVELS, STIMULATES NEUROGENESIS AND REVERSES THE INHIBITORY EFFECTS OF STRESS, BUT THIS EFFECT IS EVIDENT ONLY AFTER 3-4 WEEKS OF ADMINISTRATION, THE TIME COURSE FOR MATURATION OF NEW NEURONS. THE ABLATION OF HIPPOCAMPAL NEUROGENESIS BLOCKS THE BEHAVIOURAL EFFECTS OF ANTIDEPRESSANTS IN ANIMAL MODELS. THE ABOVE FINDINGS SUGGEST NEW POSSIBLE TARGETS FOR THE PHARMACOTHERAPY OF DEPRESSION SUCH AS NEUROTROPHIC FACTORS, THEIR RECEPTORS AND RELATED INTRACELLULAR SIGNALLING CASCADES; AGENTS COUNTERACTING THE EFFECTS OF STRESS ON HIPPOCAMPAL NEUROGENESIS (INCLUDING ANTAGONISTS OF CORTICOSTEROIDS, INFLAMMATORY CYTOKINES AND THEIR RECEPTORS); AND AGENTS FACILITATING THE ACTIVATION OF GENE EXPRESSION AND INCREASING THE TRANSCRIPTION OF NEUROTROPHINS IN THE BRAIN. 2011 15 2677 30 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 4276 43 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 17 4093 31 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 18 1599 40 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 19 5199 46 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 20 1967 43 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