1 1614 126 DNA METHYLTRANSFERASE 3A IS INVOLVED IN THE SUSTAINED EFFECTS OF CHRONIC STRESS ON SYNAPTIC FUNCTIONS AND BEHAVIORS. EMERGING EVIDENCE SUGGESTS THAT EPIGENETIC MECHANISMS REGULATE ABERRANT GENE TRANSCRIPTION IN STRESS-ASSOCIATED MENTAL DISORDERS. HOWEVER, IT REMAINS TO BE ELUCIDATED ABOUT THE ROLE OF DNA METHYLATION AND ITS CATALYZING ENZYMES, DNA METHYLTRANSFERASES (DNMTS), IN THIS PROCESS. HERE, WE FOUND THAT MALE RATS EXPOSED TO CHRONIC (2-WEEK) UNPREDICTABLE STRESS EXHIBITED A SUBSTANTIAL REDUCTION OF DNMT3A AFTER STRESS CESSATION IN THE PREFRONTAL CORTEX (PFC), A KEY TARGET REGION OF STRESS. TREATMENT OF UNSTRESSED CONTROL RATS WITH DNMT INHIBITORS RECAPITULATED THE EFFECT OF CHRONIC UNPREDICTABLE STRESS ON DECREASED AMPAR EXPRESSION AND FUNCTION IN PFC. IN CONTRAST, OVEREXPRESSION OF DNMT3A IN PFC OF STRESSED ANIMALS PREVENTED THE LOSS OF GLUTAMATERGIC RESPONSES. MOREOVER, THE STRESS-INDUCED BEHAVIORAL ABNORMALITIES, INCLUDING THE IMPAIRED RECOGNITION MEMORY, HEIGHTENED AGGRESSION, AND HYPERLOCOMOTION, WERE PARTIALLY ATTENUATED BY DNMT3A EXPRESSION IN PFC OF STRESSED ANIMALS. FINALLY, WE FOUND THAT THERE WERE GENOME-WIDE DNA METHYLATION CHANGES AND TRANSCRIPTOME ALTERATIONS IN PFC OF STRESSED RATS, BOTH OF WHICH WERE ENRICHED AT SEVERAL NEURAL PATHWAYS, INCLUDING GLUTAMATERGIC SYNAPSE AND MICROTUBULE-ASSOCIATED PROTEIN KINASE SIGNALING. THESE RESULTS HAVE THEREFORE RECOGNIZED THE POTENTIAL ROLE OF DNA EPIGENETIC MODIFICATION IN STRESS-INDUCED DISTURBANCE OF SYNAPTIC FUNCTIONS AND COGNITIVE AND EMOTIONAL PROCESSES. 2021 2 5007 40 PERIPHERAL NERVE INJURY IS ASSOCIATED WITH CHRONIC, REVERSIBLE CHANGES IN GLOBAL DNA METHYLATION IN THE MOUSE PREFRONTAL CORTEX. CHANGES IN BRAIN STRUCTURE AND CORTICAL FUNCTION ARE ASSOCIATED WITH MANY CHRONIC PAIN CONDITIONS INCLUDING LOW BACK PAIN AND FIBROMYALGIA. THE MAGNITUDE OF THESE CHANGES CORRELATES WITH THE DURATION AND/OR THE INTENSITY OF CHRONIC PAIN. MOST STUDIES REPORT CHANGES IN COMMON AREAS INVOLVED IN PAIN MODULATION, INCLUDING THE PREFRONTAL CORTEX (PFC), AND PAIN-RELATED PATHOLOGICAL CHANGES IN THE PFC CAN BE REVERSED WITH EFFECTIVE TREATMENT. WHILE THE MECHANISMS UNDERLYING THESE CHANGES ARE UNKNOWN, THEY MUST BE DYNAMICALLY REGULATED. EPIGENETIC MODULATION OF GENE EXPRESSION IN RESPONSE TO EXPERIENCE AND ENVIRONMENT IS REVERSIBLE AND DYNAMIC. EPIGENETIC MODULATION BY DNA METHYLATION IS ASSOCIATED WITH ABNORMAL BEHAVIOR AND PATHOLOGICAL GENE EXPRESSION IN THE CENTRAL NERVOUS SYSTEM. DNA METHYLATION MIGHT ALSO BE INVOLVED IN MEDIATING THE PATHOLOGIES ASSOCIATED WITH CHRONIC PAIN IN THE BRAIN. WE THEREFORE TESTED A) WHETHER ALTERATIONS IN DNA METHYLATION ARE FOUND IN THE BRAIN LONG AFTER CHRONIC NEUROPATHIC PAIN IS INDUCED IN THE PERIPHERY USING THE SPARED NERVE INJURY MODAL AND B) WHETHER THESE INJURY-ASSOCIATED CHANGES ARE REVERSIBLE BY INTERVENTIONS THAT REVERSE THE PATHOLOGIES ASSOCIATED WITH CHRONIC PAIN. SIX MONTHS FOLLOWING PERIPHERAL NERVE INJURY, ABNORMAL SENSORY THRESHOLDS AND INCREASED ANXIETY WERE ACCOMPANIED BY DECREASED GLOBAL METHYLATION IN THE PFC AND THE AMYGDALA BUT NOT IN THE VISUAL CORTEX OR THE THALAMUS. ENVIRONMENTAL ENRICHMENT ATTENUATED NERVE INJURY-INDUCED HYPERSENSITIVITY AND REVERSED THE CHANGES IN GLOBAL PFC METHYLATION. FURTHERMORE, GLOBAL PFC METHYLATION CORRELATED WITH MECHANICAL AND THERMAL SENSITIVITY IN NEUROPATHIC MICE. IN SUMMARY, INDUCTION OF CHRONIC PAIN BY PERIPHERAL NERVE INJURY IS ASSOCIATED WITH EPIGENETIC CHANGES IN THE BRAIN. THESE CHANGES ARE DETECTED LONG AFTER THE ORIGINAL INJURY, AT A LONG DISTANCE FROM THE SITE OF INJURY AND ARE REVERSIBLE WITH ENVIRONMENTAL MANIPULATION. CHANGES IN BRAIN STRUCTURE AND CORTICAL FUNCTION THAT ARE ASSOCIATED WITH CHRONIC PAIN CONDITIONS MAY THEREFORE BE MEDIATED BY EPIGENETIC MECHANISMS. 2013 3 6427 37 THE TRANSITION FROM ACUTE TO CHRONIC PAIN: DYNAMIC EPIGENETIC REPROGRAMMING OF THE MOUSE PREFRONTAL CORTEX UP TO 1 YEAR AFTER NERVE INJURY. CHRONIC PAIN IS ASSOCIATED WITH PERSISTENT STRUCTURAL AND FUNCTIONAL CHANGES THROUGHOUT THE NEUROAXIS, INCLUDING IN THE PREFRONTAL CORTEX (PFC). THE PFC IS IMPORTANT IN THE INTEGRATION OF SENSORY, COGNITIVE, AND EMOTIONAL INFORMATION AND IN CONDITIONED PAIN MODULATION. WE PREVIOUSLY REPORTED WIDESPREAD EPIGENETIC REPROGRAMMING IN THE PFC MANY MONTHS AFTER NERVE INJURY IN RODENTS. EPIGENETIC MODIFICATIONS, INCLUDING DNA METHYLATION, CAN DRIVE CHANGES IN GENE EXPRESSION WITHOUT MODIFYING DNA SEQUENCES. TO DATE, LITTLE IS KNOWN ABOUT EPIGENETIC DYSREGULATION AT THE ONSET OF ACUTE PAIN OR HOW IT PROGRESSES AS PAIN TRANSITIONS FROM ACUTE TO CHRONIC. WE HYPOTHESIZE THAT ACUTE PAIN AFTER INJURY RESULTS IN RAPID AND PERSISTENT EPIGENETIC REMODELLING IN THE PFC THAT EVOLVES AS PAIN BECOMES CHRONIC. WE FURTHER PROPOSE THAT UNDERSTANDING EPIGENETIC REMODELLING WILL PROVIDE INSIGHTS INTO THE MECHANISMS DRIVING PAIN-RELATED CHANGES IN THE BRAIN. EPIGENOME-WIDE ANALYSIS WAS PERFORMED IN THE MOUSE PFC 1 DAY, 2 WEEKS, 6 MONTHS, AND 1 YEAR AFTER PERIPHERAL INJURY USING THE SPARED NERVE INJURY IN MICE. SPARED NERVE INJURY RESULTED IN RAPID AND PERSISTENT CHANGES IN DNA METHYLATION, WITH ROBUST DIFFERENTIAL METHYLATION OBSERVED BETWEEN SPARED NERVE INJURY AND SHAM-OPERATED CONTROL MICE AT ALL TIME POINTS. HUNDREDS OF DIFFERENTIALLY METHYLATED GENES WERE IDENTIFIED, INCLUDING MANY WITH KNOWN FUNCTION IN PAIN. PATHWAY ANALYSIS REVEALED ENRICHMENT IN GENES RELATED TO STIMULUS RESPONSE AT EARLY TIME POINTS, IMMUNE FUNCTION AT LATER TIME POINTS, AND ACTIN AND CYTOSKELETAL REGULATION THROUGHOUT THE TIME COURSE. THESE RESULTS EMPHASIZE THE IMPORTANCE OF CONSIDERING PAIN CHRONICITY IN BOTH PAIN RESEARCH AND IN TREATMENT OPTIMIZATION. 2020 4 377 36 AN EPIGENETIC HYPOTHESIS FOR THE GENOMIC MEMORY OF PAIN. CHRONIC PAIN IS ACCOMPANIED WITH LONG-TERM SENSORY, AFFECTIVE AND COGNITIVE DISTURBANCES. WHAT ARE THE MECHANISMS THAT MEDIATE THE LONG-TERM CONSEQUENCES OF PAINFUL EXPERIENCES AND EMBED THEM IN THE GENOME? WE HYPOTHESIZE THAT ALTERATIONS IN DNA METHYLATION, AN ENZYMATIC COVALENT MODIFICATION OF CYTOSINE BASES IN DNA, SERVE AS A "GENOMIC" MEMORY OF PAIN IN THE ADULT CORTEX. DNA METHYLATION IS AN EPIGENETIC MECHANISM FOR LONG-TERM REGULATION OF GENE EXPRESSION. NEURONAL PLASTICITY AT THE NEUROANATOMICAL, FUNCTIONAL, MORPHOLOGICAL, PHYSIOLOGICAL AND MOLECULAR LEVELS HAS BEEN DEMONSTRATED THROUGHOUT THE NEUROAXIS IN RESPONSE TO PERSISTENT PAIN, INCLUDING IN THE ADULT PREFRONTAL CORTEX (PFC). WE HAVE PREVIOUSLY REPORTED WIDESPREAD CHANGES IN GENE EXPRESSION AND DNA METHYLATION IN THE PFC MANY MONTHS FOLLOWING PERIPHERAL NERVE INJURY. IN SUPPORT OF THIS HYPOTHESIS, WE SHOW HERE THAT UP-REGULATION OF A GENE INVOLVED WITH SYNAPTIC FUNCTION, SYNAPTOTAGMIN II (SYT2), IN THE PFC IN A CHRONIC PAIN MODEL IS ASSOCIATED WITH LONG-TERM CHANGES IN DNA METHYLATION. THE CHALLENGES OF UNDERSTANDING THE CONTRIBUTIONS OF EPIGENETIC MECHANISMS SUCH AS DNA METHYLATION WITHIN THE PFC TO PAIN CHRONICITY AND THEIR THERAPEUTIC IMPLICATIONS ARE DISCUSSED. 2015 5 4628 39 NEUROEPIGENETIC ALTERATIONS IN THE PREFRONTAL CORTEX OF TYPE 2 DIABETIC MICE THROUGH DNA HYPERMETHYLATION. BACKGROUND: DNA METHYLATION CHANGES HAVE KNOWN TO DOWNREGULATE SEVERAL REGULATORY PROTEINS EPIGENETICALLY DURING VARIOUS NEURODEGENERATIVE DISORDERS. OUR STUDY AIMS TO UNDERSTAND THE EFFECT OF THIS GLOBAL DNA METHYLATION ON THE CEREBRAL COMPLICATIONS OF TYPE 2 DIABETES MICE, AND ITS NOTABLE EFFECT ON MAINTAINING THE SYNAPTIC FIDELITY. METHODS AND RESULTS: CHRONIC HIGH FAT DIET AND STREPTOZOTOCIN-INDUCED DIABETIC MICE WERE STUDIED FOR THE NEUROBEHAVIORAL AND NEUROANATOMIC PARAMETERS PERTAINING TO PREFRONTAL CORTEX, SUBSEQUENTLY ELUCIDATING THE ASSOCIATED CHANGES IN DNA METHYLATION WITHIN THESE DIABETIC BRAINS. FURTHER, THE IMPACT OF THIS EPIGENETIC DYSREGULATION ON HSF1, BDNF AND PSD95 WERE STUDIED BY ASSESSING THE BINDING AFFINITY AND LEVEL OF % METHYLATION WITHIN THE PROMOTER SITE OF THEIR RESPECTIVE GENES. OUR STUDY SUGGEST INCREASED DNMT ABERRATIONS WITHIN THE PREFRONTAL CORTEX, WITH INCREASED MECP2 LEVELS, CONFIRMING DNA HYPERMETHYLATION. THIS WAS IN ACCORDANCE WITH THE ALTERED NEUROBEHAVIORAL CHANGES. FURTHER, THE HYPERMETHYLATION WAS FOUND TO PARTICIPATE IN GENE SILENCING OF HSF1, BDNF AND PSD95 PROTEINS, RESPONSIBLE FOR MAINTAINING THE SYNAPTIC FIDELITY. CONCLUSION: OVERALL, OUR STUDY CONCLUDES THE PLAUSIBLE INVOLVEMENT OF NEUROEPIGENETIC ALTERATIONS IN THE PREFRONTAL CORTEX (PFC) OF THE TYPE 2 DIABETES MICE, SPECIFICALLY DNA HYPERMETHYLATION. PFC PLAYS A CENTRAL ROLE IN MODULATING COGNITIVE AND OTHER EXECUTIVE FUNCTIONS THROUGH ITS CONNECTION WITH SEVERAL BRAIN REGIONS, AND THUS THERAPEUTIC STRATEGIES TARGETING EPIGENETIC MODULATIONS IN IT, CAN PAVE A WAY IN CONTROLLING SEVERAL NEUROLOGICAL ALTERATIONS IN THE BRAIN. 2022 6 1698 34 DYNAMIC EFFECTS OF EARLY ADOLESCENT STRESS ON DEPRESSIVE-LIKE BEHAVIORS AND EXPRESSION OF CYTOKINES AND JMJD3 IN THE PREFRONTAL CORTEX AND HIPPOCAMPUS OF RATS. AIMS: EXPRESSION OF INFLAMMATORY CYTOKINES IN THE BRAIN HAS BEEN REPORTED TO BE INVOLVED IN THE PATHOGENESIS OF AND SUSCEPTIBILITY TO DEPRESSION. JUMONJI DOMAIN-CONTAINING 3 (JMJD3), WHICH IS A HISTONE H3 LYSINE 27 (H3K27) DEMETHYLASE AND CAN REGULATE MICROGLIAL ACTIVATION, HAS BEEN REGARDED AS A CRUCIAL ELEMENT IN THE EXPRESSION OF INFLAMMATORY CYTOKINES. FURTHERMORE, RECENT STUDIES HIGHLIGHTED THE FACT THAT LIPOPOLYSACCHARIDES INDUCE DEPRESSIVE-LIKE BEHAVIORS AND HIGHER JMJD3 EXPRESSION AND LOWER H3K27ME3 EXPRESSION IN THE BRAIN. HOWEVER, WHETHER THE PROCESS OF JMJD3 MEDIATING INFLAMMATORY CYTOKINES WAS INVOLVED IN THE SUSCEPTIBILITY TO DEPRESSION DUE TO EARLY-LIFE STRESS REMAINED ELUSIVE. METHODS: RATS EXPOSED TO CHRONIC UNPREDICTABLE MILD STRESS (CUMS) IN ADOLESCENCE WERE USED IN ORDER TO DETECT DYNAMIC ALTERATIONS IN DEPRESSIVE-LIKE BEHAVIORS AND EXPRESSION OF CYTOKINES, JMJD3, AND H3K27ME3 IN THE PREFRONTAL CORTEX AND HIPPOCAMPUS. MOREOVER, MINOCYCLINE, AN INHIBITOR OF MICROGLIAL ACTIVATION, WAS EMPLOYED TO OBSERVE THE PROTECTIVE EFFECTS. RESULTS: OUR RESULTS SHOWED THAT CUMS DURING THE ADOLESCENT PERIOD INDUCED DEPRESSIVE-LIKE BEHAVIORS, OVER-EXPRESSION OF CYTOKINES, AND INCREASED JMJD3 AND DECREASED H3K27ME3 EXPRESSION IN THE PREFRONTAL CORTEX AND HIPPOCAMPUS OF BOTH ADOLESCENT AND ADULT RATS. HOWEVER, MINOCYCLINE RELIEVED ALL THE ALTERATIONS. CONCLUSION: THE STUDY REVEALED THAT JMJD3 MIGHT BE INVOLVED IN THE SUSCEPTIBILITY TO DEPRESSIVE-LIKE BEHAVIORS BY MODULATING H3K27ME3 AND PRO-INFLAMMATORY CYTOKINE EXPRESSION IN THE PREFRONTAL CORTEX AND HIPPOCAMPUS OF RATS THAT HAD BEEN STRESSED DURING EARLY ADOLESCENCE. 2018 7 5199 37 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 8 5019 41 PERSISTENT INFLAMMATORY PAIN IS LINKED WITH ANXIETY-LIKE BEHAVIORS, INCREASED BLOOD CORTICOSTERONE, AND REDUCED GLOBAL DNA METHYLATION IN THE RAT AMYGDALA. CHRONIC PAIN INCREASES THE RISK OF DEVELOPING ANXIETY, WITH LIMBIC AREAS BEING LIKELY NEUROLOGICAL SUBSTRATES. DESPITE HIGH CLINICAL RELEVANCE, LITTLE IS KNOWN ABOUT THE PRECISE BEHAVIORAL, HORMONAL, AND BRAIN NEUROPLASTIC CORRELATES OF ANXIETY IN THE CONTEXT OF PERSISTENT PAIN. PREVIOUS STUDIES HAVE SHOWN THAT DECREASED NOCICEPTIVE THRESHOLDS IN CHRONIC PAIN MODELS ARE PARALLELED BY ANXIETY-LIKE BEHAVIOR IN RATS, BUT THERE ARE CONFLICTING IDEAS REGARDING ITS EFFECTS ON THE STRESS RESPONSE AND CIRCULATING CORTICOSTERONE LEVELS. EVEN LESS IS KNOWN ABOUT THE MOLECULAR MECHANISMS THROUGH WHICH THE BRAIN ENCODES PAIN-RELATED ANXIETY. THIS STUDY EXAMINES HOW PERSISTENT INFLAMMATORY PAIN IN A RAT MODEL WOULD IMPACT ANXIETY-LIKE BEHAVIORS AND CORTICOSTERONE RELEASE, AND WHETHER THESE CHANGES WOULD BE REFLECTED IN LEVELS OF GLOBAL DNA METHYLATION IN BRAIN AREAS INVOLVED IN STRESS REGULATION. COMPLETE FREUND'S ADJUVANT (CFA) OR SALINE WAS ADMINISTERED IN THE RIGHT HINDPAW OF ADULT MALE WISTAR RATS. BEHAVIORAL TESTING INCLUDED THE MEASUREMENT OF NOCICEPTIVE THRESHOLDS (DIGITAL ANESTHESIOMETER), MOTOR FUNCTION (OPEN FIELD TEST), AND ANXIETY-LIKE BEHAVIORS (ELEVATED PLUS MAZE AND THE DARK-LIGHT BOX TEST). CORTICOSTERONE WAS MEASURED VIA RADIOIMMUNOASSAY. GLOBAL DNA METHYLATION (ENZYME IMMUNOASSAY) AS WELL AS DNMT3A LEVELS (WESTERN BLOTTING) WERE QUANTIFIED IN THE AMYGDALA, PREFRONTAL CORTEX, AND VENTRAL HIPPOCAMPUS. CFA ADMINISTRATION RESULTED IN PERSISTENT REDUCTION IN NOCICEPTIVE THRESHOLD IN THE ABSENCE OF LOCOMOTOR ABNORMALITIES. INCREASED ANXIETY-LIKE BEHAVIORS WERE OBSERVED IN THE ELEVATED PLUS MAZE AND WERE ACCOMPANIED BY INCREASED BLOOD CORTICOSTERONE LEVELS 10 DAYS AFTER PAIN INDUCTION. GLOBAL DNA METHYLATION WAS DECREASED IN THE AMYGDALA, WITH NO CHANGES IN DNMT3A ABUNDANCE IN ANY OF THE REGIONS EXAMINED. PERSISTENT INFLAMMATORY PAIN PROMOTES ANXIETY -LIKE BEHAVIORS, HPA AXIS ACTIVATION, AND EPIGENETIC REGULATION THROUGH DNA METHYLATION IN THE AMYGDALA. THESE FINDINGS DESCRIBE A MOLECULAR MECHANISM THAT LINKS PAIN AND STRESS IN A WELL-CHARACTERIZED RODENT MODEL. 2022 9 5974 38 TET1 IN NUCLEUS ACCUMBENS OPPOSES DEPRESSION- AND ANXIETY-LIKE BEHAVIORS. DEPRESSION IS A LEADING CAUSE OF DISEASE BURDEN, YET CURRENT THERAPIES FULLY TREAT <50% OF AFFECTED INDIVIDUALS. INCREASING EVIDENCE IMPLICATES EPIGENETIC MECHANISMS IN DEPRESSION AND ANTIDEPRESSANT ACTION. HERE WE EXAMINED A POSSIBLE ROLE FOR THE DNA DIOXYGENASE, TEN-ELEVEN TRANSLOCATION PROTEIN 1 (TET1), IN DEPRESSION-RELATED BEHAVIORAL ABNORMALITIES. WE APPLIED CHRONIC SOCIAL DEFEAT STRESS, AN ETHOLOGICALLY VALIDATED MOUSE MODEL OF DEPRESSION-LIKE BEHAVIORS, AND EXAMINED TET1 EXPRESSION CHANGES IN NUCLEUS ACCUMBENS (NAC), A KEY BRAIN REWARD REGION. WE SHOW DECREASED TET1 EXPRESSION IN NAC IN STRESS-SUSCEPTIBLE MICE ONLY. SURPRISINGLY, SELECTIVE KNOCKOUT OF TET1 IN NAC NEURONS OF ADULT MICE PRODUCED ANTIDEPRESSANT-LIKE EFFECTS IN SEVERAL BEHAVIORAL ASSAYS. TO IDENTIFY TET1 TARGETS THAT MEDIATE THESE ACTIONS, WE PERFORMED RNASEQ ON NAC AFTER CONDITIONAL DELETION OF TET1 AND FOUND THAT IMMUNE-RELATED GENES ARE THE MOST HIGHLY DYSREGULATED. MOREOVER, MANY OF THESE GENES ARE ALSO UPREGULATED IN THE NAC OF RESILIENT MICE AFTER CHRONIC SOCIAL DEFEAT STRESS. THESE FINDINGS REVEAL A NOVEL ROLE FOR TET1, AN ENZYME IMPORTANT FOR DNA HYDROXYMETHYLATION, IN THE BRAIN'S REWARD CIRCUITRY IN MODULATING STRESS RESPONSES IN MICE. WE ALSO IDENTIFY A SUBSET OF GENES THAT ARE REGULATED BY TET1 IN THIS CIRCUITRY. THESE FINDINGS PROVIDE NEW INSIGHT INTO THE PATHOPHYSIOLOGY OF DEPRESSION, WHICH CAN AID IN FUTURE ANTIDEPRESSANT DRUG DISCOVERY EFFORTS. 2017 10 5820 38 STRESS DYNAMICALLY REGULATES BEHAVIOR AND GLUTAMATERGIC GENE EXPRESSION IN HIPPOCAMPUS BY OPENING A WINDOW OF EPIGENETIC PLASTICITY. EXCITATORY AMINO ACIDS PLAY A KEY ROLE IN BOTH ADAPTIVE AND DELETERIOUS EFFECTS OF STRESSORS ON THE BRAIN, AND DYSREGULATED GLUTAMATE HOMEOSTASIS HAS BEEN ASSOCIATED WITH PSYCHIATRIC AND NEUROLOGICAL DISORDERS. HERE, WE ELUCIDATE MECHANISMS OF EPIGENETIC PLASTICITY IN THE HIPPOCAMPUS IN THE INTERACTIONS BETWEEN A HISTORY OF CHRONIC STRESS AND FAMILIAR AND NOVEL ACUTE STRESSORS THAT ALTER EXPRESSION OF ANXIETY- AND DEPRESSIVE-LIKE BEHAVIORS. WE DEMONSTRATE THAT ACUTE RESTRAINT AND ACUTE FORCED SWIM STRESSORS INDUCE DIFFERENTIAL EFFECTS ON THESE BEHAVIORS IN NAIVE MICE AND IN MICE WITH A HISTORY OF CHRONIC-RESTRAINT STRESS (CRS). THEY REVEAL A KEY ROLE FOR EPIGENETIC UP- AND DOWN-REGULATION OF THE PUTATIVE PRESYNAPTIC TYPE 2 METABOTROPIC GLUTAMATE (MGLU2) RECEPTORS AND THE POSTSYNAPTIC NR1/NMDA RECEPTORS IN THE HIPPOCAMPUS AND PARTICULARLY IN THE DENTATE GYRUS (DG), A REGION OF ACTIVE NEUROGENESIS AND A TARGET OF ANTIDEPRESSANT TREATMENT. WE SHOW CHANGES IN DG LONG-TERM POTENTIATION (LTP) THAT PARALLEL BEHAVIORAL RESPONSES, WITH HABITUATION TO THE SAME ACUTE RESTRAINT STRESSOR AND SENSITIZATION TO A NOVEL FORCED-SWIM STRESSOR. IN WT MICE AFTER CRS AND IN UNSTRESSED MICE WITH A BDNF LOSS-OF-FUNCTION ALLELE (BDNF VAL66MET), WE SHOW THAT THE EPIGENETIC ACTIVATOR OF HISTONE ACETYLATION, P300, PLAYS A PIVOTAL ROLE IN THE DYNAMIC UP- AND DOWN-REGULATION OF MGLU2 IN HIPPOCAMPUS VIA HISTONE-3-LYSINE-27-ACETYLATION (H3K27AC) WHEN ACUTE STRESSORS ARE APPLIED. THESE HIPPOCAMPAL RESPONSES REVEAL A WINDOW OF EPIGENETIC PLASTICITY THAT MAY BE USEFUL FOR TREATMENT OF DISORDERS IN WHICH GLUTAMATERGIC TRANSMISSION IS DYSREGULATED. 2015 11 5467 41 RESILIENT PHENOTYPE IN CHRONIC MILD STRESS PARADIGM IS ASSOCIATED WITH ALTERED EXPRESSION LEVELS OF MIR-18A-5P AND SEROTONIN 5-HT(1A) RECEPTOR IN DORSAL PART OF THE HIPPOCAMPUS. DISTURBED SEROTONERGIC SIGNALING IN THE HIPPOCAMPUS OBSERVED IN MANY INDIVIDUALS VULNERABLE TO STRESS HAS BEEN SUGGESTED AS ONE OF THE PRIMARY FACTORS CONTRIBUTING TO THE DEVELOPMENT OF DEPRESSION. HOWEVER, LITTLE IS KNOWN ABOUT THE PHYSIOLOGY OF THE BRAIN IN THE RESILIENT PHENOTYPE. RESILIENT SUBJECTS MAINTAIN A POSITIVE MOOD AND PSYCHOLOGICAL BALANCE DESPITE BEING UNDER THE STRESS INFLUENCE. IN OUR STUDY, WE GENERATED STRESS-VULNERABLE AND RESILIENT RATS BY USING A CHRONIC MILD STRESS (CMS) PARADIGM. USING DIFFERENT MOLECULAR APPROACHES, WE REVEALED THAT RESILIENT ANIMALS EXHIBITED A SIGNIFICANTLY DECREASED EXPRESSION LEVEL OF MIR-18A-5P AND, IN THE SAME TIME, AN ELEVATED LEVEL OF 5-HT1AR IN DORSAL, BUT NOT VENTRAL, PART OF THE HIPPOCAMPUS. DESCRIBED BIOCHEMICAL CHANGES WERE NOT OBSERVED IN ANIMALS BEHAVIORALLY VULNERABLE TO STRESS. FURTHER, IN VITRO ANALYSIS SHOWED THAT MIR-18A-5P MAY BE A NEGATIVE EPIGENETIC REGULATOR OF 5-HT1AR SINCE THE TREATMENT OF ADULT HIPPOCAMPAL NEURONS WITH MIR-18A-5P MIMIC SIGNIFICANTLY LOWERED THE EXPRESSION LEVEL OF MRNA ENCODING 5-HT1AR. MOREOVER, BIOINFORMATIC ANALYSIS OF POTENTIAL TARGET GENES EXPRESSED IN THE HIPPOCAMPUS AND BEING REGULATED BY MIR-18A-5P SHOWED THAT THIS MICRORNA MAY REGULATE BIOLOGICAL PROCESSES, SUCH AS AXONOGENESIS, WHICH ARE IMPORTANT IN THE FUNCTIONING OF THE HIPPOCAMPUS IN BOTH RATS AND HUMANS. ALL THESE MOLECULAR FEATURES MAY CONTRIBUTE TO SEROTONERGIC HOMEOSTATIC BALANCE AT THE LEVEL OF SEROTONIN TURNOVER OBSERVED IN HIPPOCAMPI OF RESILIENT BUT NOT STRESS-VULNERABLE RATS. DELINEATION OF FURTHER MOLECULAR AND BIOCHEMICAL MARKERS UNDERLYING RESILIENCE TO STRESS MAY CONTRIBUTE TO THE DEVELOPMENT OF NEW ANTIDEPRESSANT STRATEGIES WHICH WILL RESTORE RESILIENT PHENOTYPE IN DEPRESSED PATIENTS. 2019 12 1790 40 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 13 5624 31 SELECTIVE BOOSTING OF TRANSCRIPTIONAL AND BEHAVIORAL RESPONSES TO DRUGS OF ABUSE BY HISTONE DEACETYLASE INHIBITION. HISTONE ACETYLATION AND OTHER MODIFICATIONS OF THE CHROMATIN ARE IMPORTANT REGULATORS OF GENE EXPRESSION AND, CONSEQUENTLY, MAY CONTRIBUTE TO DRUG-INDUCED BEHAVIORS AND NEUROPLASTICITY. EARLIER STUDIES HAVE SHOWN THAT A REDUCTION IN HISTONE DEACETYLASE (HDAC) ACTIVITY RESULTS IN THE ENHANCEMENT OF SOME PSYCHOSTIMULANT-INDUCED BEHAVIORS. IN THIS STUDY, WE EXTEND THOSE SEMINAL FINDINGS BY SHOWING THAT THE ADMINISTRATION OF THE HDAC INHIBITOR SODIUM BUTYRATE ENHANCES MORPHINE-INDUCED LOCOMOTOR SENSITIZATION AND CONDITIONED PLACE PREFERENCE. IN CONTRAST, THIS COMPOUND HAS NO EFFECTS ON THE DEVELOPMENT OF MORPHINE TOLERANCE AND DEPENDENCE. SIMILAR EFFECTS WERE OBSERVED FOR COCAINE AND ETHANOL-INDUCED BEHAVIORS. THESE BEHAVIORAL CHANGES WERE ACCOMPANIED BY A SELECTIVE BOOSTING OF A COMPONENT OF THE TRANSCRIPTIONAL PROGRAM ACTIVATED BY CHRONIC MORPHINE ADMINISTRATION THAT INCLUDED CIRCADIAN CLOCK GENES AND OTHER GENES RELEVANT TO ADDICTIVE BEHAVIOR. OUR RESULTS SUPPORT A SPECIFIC FUNCTION FOR HISTONE ACETYLATION AND THE EPIGENETIC MODULATION OF TRANSCRIPTION AT A REDUCED NUMBER OF BIOLOGICALLY RELEVANT LOCI ON NON-HOMEOSTATIC, LONG-LASTING, DRUG-INDUCED BEHAVIORAL PLASTICITY. 2009 14 3341 32 HISTONE DEACETYLASE-2 IS INVOLVED IN STRESS-INDUCED COGNITIVE IMPAIRMENT VIA HISTONE DEACETYLATION AND PI3K/AKT SIGNALING PATHWAY MODIFICATION. EXPOSURE TO CHRONIC STRESS UPREGULATES BLOOD GLUCOCORTICOID LEVELS AND IMPAIRS COGNITION VIA DIVERSE EPIGENETIC MECHANISMS, SUCH AS HISTONE DEACETYLATION. HISTONE DEACETYLATION CAN LEAD TO TRANSCRIPTIONAL SILENCING OF MANY PROTEINS INVOLVED IN COGNITION AND MAY ALSO CAUSE LEARNING AND MEMORY DYSFUNCTION. HISTONE DEACETYLASE?2 (HDAC2) HAS BEEN DEMONSTRATED TO EPIGENETICALLY BLOCK COGNITION VIA A REDUCTION IN THE HISTONE ACETYLATION LEVEL; HOWEVER, IT IS UNKNOWN WHETHER HDAC2 IS INVOLVED IN THE COGNITIVE DECLINE INDUCED BY CHRONIC STRESS. TO THE BEST OF AUTHORS' KNOWLEDGE, THIS IS THE FIRST STUDY TO DEMONSTRATE THAT THE STRESS HORMONE CORTICOSTEROID UPREGULATE HDAC2 PROTEIN LEVELS IN NEURO?2A CELLS AND CAUSE CELL INJURIES. HDAC2 KNOCKDOWN RESULTED IN A SIGNIFICANT AMELIORATION OF THE PATHOLOGICAL CHANGES IN N2A CELLS VIA THE UPREGULATION OF HISTONE ACETYLATION AND MODIFICATIONS IN THE PHOSPHOINOSITIDE 3?KINASE/PROTEIN KINASE B SIGNALING PATHWAY. IN ADDITION, THE HDAC2 PROTEIN LEVELS WERE UPREGULATED IN 12?MONTH?OLD FEMALE C57BL/6J MICE UNDER CHRONIC STRESS IN VIVO. TAKEN TOGETHER, THESE FINDINGS SUGGESTED THAT HDAC2 MAY BE AN IMPORTANT NEGATIVE REGULATOR INVOLVED IN CHRONIC STRESS?INDUCED COGNITIVE IMPAIRMENT. 2017 15 3952 35 LOCUS-SPECIFIC EPIGENETIC REMODELING CONTROLS ADDICTION- AND DEPRESSION-RELATED BEHAVIORS. CHRONIC EXPOSURE TO DRUGS OF ABUSE OR STRESS REGULATES TRANSCRIPTION FACTORS, CHROMATIN-MODIFYING ENZYMES AND HISTONE POST-TRANSLATIONAL MODIFICATIONS IN DISCRETE BRAIN REGIONS. GIVEN THE PROMISCUITY OF THE ENZYMES INVOLVED, IT HAS NOT YET BEEN POSSIBLE TO OBTAIN DIRECT CAUSAL EVIDENCE TO IMPLICATE THE REGULATION OF TRANSCRIPTION AND CONSEQUENT BEHAVIORAL PLASTICITY BY CHROMATIN REMODELING THAT OCCURS AT A SINGLE GENE. WE INVESTIGATED THE MECHANISM LINKING CHROMATIN DYNAMICS TO NEUROBIOLOGICAL PHENOMENA BY APPLYING ENGINEERED TRANSCRIPTION FACTORS TO SELECTIVELY MODIFY CHROMATIN AT A SPECIFIC MOUSE GENE IN VIVO. WE FOUND THAT HISTONE METHYLATION OR ACETYLATION AT THE FOSB LOCUS IN NUCLEUS ACCUMBENS, A BRAIN REWARD REGION, WAS SUFFICIENT TO CONTROL DRUG- AND STRESS-EVOKED TRANSCRIPTIONAL AND BEHAVIORAL RESPONSES VIA INTERACTIONS WITH THE ENDOGENOUS TRANSCRIPTIONAL MACHINERY. THIS APPROACH ALLOWED US TO RELATE THE EPIGENETIC LANDSCAPE AT A GIVEN GENE DIRECTLY TO REGULATION OF ITS EXPRESSION AND TO ITS SUBSEQUENT EFFECTS ON REWARD BEHAVIOR. 2014 16 431 45 ANTIDEPRESSANT ADMINISTRATION MODULATES STRESS-INDUCED DNA METHYLATION AND DNA METHYLTRANSFERASE EXPRESSION IN RAT PREFRONTAL CORTEX AND HIPPOCAMPUS. STRESS AND ANTIDEPRESSANT TREATMENT CAN MODULATE DNA METHYLATION IN PROMOTER REGION OF GENES RELATED TO NEUROPLASTICITY AND MOOD REGULATION, THUS IMPLICATING THIS EPIGENETIC MECHANISM IN DEPRESSION NEUROBIOLOGY AND TREATMENT. ACCORDINGLY, SYSTEMIC ADMINISTRATION OF DNA METHYLTRANSFERASE (DNMT) INHIBITORS INDUCES ANTIDEPRESSANT-LIKE EFFECTS IN RODENTS. DNA METHYLATION IS CONVEYED BY DNMT 1, 3A AND 3B ISOFORMS, WHICH ARE DIFFERENTIALLY EXPRESSED IN THE BRAIN. IN ORDER TO INVESTIGATE IF THE BEHAVIORAL EFFECTS OF ANTIDEPRESSANTS COULD BE ASSOCIATED WITH CHANGES IN DNA METHYLATION AND DNMT EXPRESSION, WE INVESTIGATED THE EFFECTS INDUCED BY ACUTE AND REPEATED ANTIDEPRESSANT TREATMENT ON DNA METHYLATION AND DNMT EXPRESSION (1, 3A AND 3B ISOFORMS) IN DIFFERENT BRAIN REGIONS OF RATS EXPOSED TO A STRESS MODEL OF DEPRESSION, THE LEARNED HELPLESSNESS (LH). THEREFORE, RATS WERE EXPOSED TO PRETEST AND TREATED WITH ONE OR SEVEN INJECTIONS OF VEHICLE OR IMIPRAMINE (15 MG KG(-1)), WITH TEST SESSION PERFORMED ONE HOUR AFTER THE LAST INJECTION. CHRONIC, BUT NOT ACUTE, IMIPRAMINE ADMINISTRATION ATTENUATED ESCAPE FAILURES DURING THE TEST, A WELL DESCRIBED ANTIDEPRESSANT-LIKE EFFECT IN THIS MODEL. DNA METHYLATION AND DNMT (1, 3A AND 3B) LEVELS WERE MEASURED IN THE DORSAL AND VENTRAL HIPPOCAMPUS (DHPC, VHPC) AND IN THE PREFRONTAL CORTEX (PFC) OF RATS EXPOSED TO STRESS AND TREATMENT. STRESS INCREASED DNA METHYLATION, DNMT3A AND DNMT3B EXPRESSION IN THE DHPC AND PFC. CHRONIC, BUT NOT ACUTE, IMIPRAMINE ADMINISTRATION ATTENUATED STRESS EFFECTS ONLY IN THE PFC. THESE RESULTS SUGGEST THE REGULATION OF DNA METHYLATION IN THE PFC MAY BE AN IMPORTANT MECHANISM FOR ANTIDEPRESSANT-LIKE EFFECTS IN THE LH MODEL. 2018 17 4604 37 NEGATIVE EVIDENCE FOR A FUNCTIONAL ROLE OF NEURONAL DNMT3A IN PERSISTENT PAIN. TRADITIONALLY, NEUROSCIENCE HAS HAD TO RELY ON MIXED TISSUE ANALYSIS TO EXAMINE TRANSCRIPTIONAL AND EPIGENETIC CHANGES IN THE CONTEXT OF NERVOUS SYSTEM FUNCTION OR PATHOLOGY. HOWEVER, PARTICULARLY WHEN STUDYING CHRONIC PAIN CONDITIONS, THIS APPROACH CAN BE FLAWED, SINCE IT NEGLECTS TO TAKE INTO ACCOUNT THE SHIFTING CONTRIBUTION OF DIFFERENT CELL TYPES ACROSS EXPERIMENTAL CONDITIONS. HERE, WE DEMONSTRATE THIS USING THE EXAMPLE OF DNA METHYLTRANSFERASES (DNMTS) - A GROUP OF EPIGENETIC MODIFIERS CONSISTING OF DNMT1, DNMT3A, AND DNMT3B IN MAMMALIAN CELLS. WE USED SENSORY NEURON-SPECIFIC KNOCKOUT MICE FOR DNMT3A/3B AS WELL AS PHARMACOLOGICAL BLOCKADE OF DNMT1 TO STUDY THEIR ROLE IN NOCICEPTION. IN CONTRAST TO PREVIOUS ANALYSES ON WHOLE TISSUE, WE FIND THAT DNMT3A AND 3B PROTEIN IS NOT EXPRESSED IN ADULT DRG NEURONS, THAT NONE OF THE DNA METHYLTRANSFERASES ARE REGULATED WITH INJURY AND THAT INTERFERING WITH THEIR FUNCTION HAS NO EFFECT ON NOCICEPTION. OUR RESULTS THEREFORE CURRENTLY DO NOT SUPPORT A ROLE FOR NEURONAL DNA METHYLTRANSFERASES IN PAIN PROCESSING IN ADULT ANIMALS. 2018 18 3587 36 IMPACT OF TLR4 ON BEHAVIORAL AND COGNITIVE DYSFUNCTIONS ASSOCIATED WITH ALCOHOL-INDUCED NEUROINFLAMMATORY DAMAGE. TOLL-LIKE RECEPTORS (TLRS) PLAY AN IMPORTANT ROLE IN THE INNATE IMMUNE RESPONSE, AND EMERGING EVIDENCE INDICATES THEIR ROLE IN BRAIN INJURY AND NEURODEGENERATION. OUR RECENT RESULTS HAVE DEMONSTRATED THAT ETHANOL IS CAPABLE OF ACTIVATING GLIAL TLR4 RECEPTORS AND THAT THE ELIMINATION OF THESE RECEPTORS IN MICE PROTECTS AGAINST ETHANOL-INDUCED GLIAL ACTIVATION, INDUCTION OF INFLAMMATORY MEDIATORS AND APOPTOSIS. THIS STUDY WAS DESIGNED TO ASSESS WHETHER ETHANOL-INDUCED INFLAMMATORY DAMAGE CAUSES BEHAVIORAL AND COGNITIVE CONSEQUENCES, AND IF BEHAVIORAL ALTERATIONS ARE DEPENDENT OF TLR4 FUNCTIONS. HERE WE SHOW IN MICE DRINKING ALCOHOL FOR 5MONTHS, FOLLOWED BY A 15-DAY WITHDRAWAL PERIOD, THAT ACTIVATION OF THE ASTROGLIAL AND MICROGLIAL CELLS IN FRONTAL CORTEX AND STRIATUM IS MAINTAINED AND THAT THESE EVENTS ARE ASSOCIATED WITH COGNITIVE AND ANXIETY-RELATED BEHAVIORAL IMPAIRMENTS IN WILD-TYPE (WT) MICE, AS DEMONSTRATED BY TESTING THE ANIMALS WITH OBJECT MEMORY RECOGNITION, CONDITIONED TASTE AVERSION AND DARK AND LIGHT BOX ANXIETY TASKS. MICE LACKING TLR4 RECEPTORS ARE PROTECTED AGAINST ETHANOL-INDUCED INFLAMMATORY DAMAGE, AND BEHAVIORAL ASSOCIATED EFFECTS. WE FURTHER ASSESS THE POSSIBILITY OF THE EPIGENETIC MODIFICATIONS PARTICIPATING IN SHORT- OR LONG-TERM BEHAVIORAL EFFECTS ASSOCIATED WITH NEUROINFLAMMATORY DAMAGE. WE SHOW THAT CHRONIC ALCOHOL TREATMENT DECREASES H4 HISTONE ACETYLATION AND HISTONE ACETYLTRANSFERASES ACTIVITY IN FRONTAL CORTEX, STRIATUM AND HIPPOCAMPUS OF WT MICE. ALTERATIONS IN CHROMATIN STRUCTURE WERE NOT OBSERVED IN TLR4(-/-) MICE. THESE RESULTS PROVIDE THE FIRST EVIDENCE OF THE ROLE THAT TLR4 FUNCTIONS PLAY IN THE BEHAVIORAL CONSEQUENCES OF ALCOHOL-INDUCED INFLAMMATORY DAMAGE AND SUGGEST THAT THE EPIGENETIC MODIFICATIONS MEDIATED BY TLR4 COULD CONTRIBUTE TO SHORT- OR LONG-TERM ALCOHOL-INDUCED BEHAVIORAL OR COGNITIVE DYSFUNCTIONS. 2011 19 584 51 BEHAVIORAL NEUROADAPTATION TO ALCOHOL: FROM GLUCOCORTICOIDS TO HISTONE ACETYLATION. A PRIME MECHANISM THAT CONTRIBUTES TO THE DEVELOPMENT AND MAINTENANCE OF ALCOHOLISM IS THE DYSREGULATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS ACTIVITY AND THE RELEASE OF GLUCOCORTICOIDS (CORTISOL IN HUMANS AND PRIMATES, CORTICOSTERONE IN RODENTS) FROM THE ADRENAL GLANDS. IN THE BRAIN, SUSTAINED, LOCAL ELEVATION OF GLUCOCORTICOID CONCENTRATION EVEN LONG AFTER CESSATION OF CHRONIC ALCOHOL CONSUMPTION COMPROMISES FUNCTIONAL INTEGRITY OF A CIRCUIT, INCLUDING THE PREFRONTAL CORTEX (PFC), THE HIPPOCAMPUS (HPC), AND THE AMYGDALA (AMG). THESE STRUCTURES ARE IMPLICATED IN LEARNING AND MEMORY PROCESSES AS WELL AS IN ORCHESTRATING NEUROADAPTIVE RESPONSES TO STRESS AND ANXIETY RESPONSES. THUS, POTENTIATION OF ANXIETY-RELATED NEUROADAPTATION BY ALCOHOL IS CHARACTERIZED BY AN ABNORMALLY AMG HYPERACTIVITY COUPLED WITH A HYPOFUNCTION OF THE PFC AND THE HPC. THIS REVIEW DESCRIBES RESEARCH ON MOLECULAR AND EPIGENETIC MECHANISMS BY WHICH ALCOHOL CAUSES DISTINCT REGION-SPECIFIC ADAPTIVE CHANGES IN GENE EXPRESSION PATTERNS AND ULTIMATELY LEADS TO A VARIETY OF COGNITIVE AND BEHAVIORAL IMPAIRMENTS ON PREFRONTAL- AND HIPPOCAMPAL-BASED TASKS. ALCOHOL-INDUCED NEUROADAPTATIONS INVOLVE THE DYSREGULATION OF NUMEROUS SIGNALING CASCADES, LEADING TO LONG-TERM CHANGES IN TRANSCRIPTIONAL PROFILES OF GENES, THROUGH THE ACTIONS OF TRANSCRIPTION FACTORS SUCH AS [CAMP RESPONSE ELEMENT-BINDING PROTEIN (CREB)] AND CHROMATIN REMODELING DUE TO POSTTRANSLATIONAL MODIFICATIONS OF HISTONE PROTEINS. WE DESCRIBE THE ROLE OF PREFRONTAL-HPC-AMG CIRCUIT IN MEDIATING THE EFFECTS OF ACUTE AND CHRONIC ALCOHOL ON LEARNING AND MEMORY, AND REGION-SPECIFIC MOLECULAR AND EPIGENETIC MECHANISMS INVOLVED IN THIS PROCESS. THIS REVIEW FIRST DISCUSSES THE IMPORTANCE OF BRAIN REGION-SPECIFIC DYSREGULATION OF GLUCOCORTICOID CONCENTRATION IN THE DEVELOPMENT OF ALCOHOL DEPENDENCE AND DESCRIBES HOW PERSISTENTLY INCREASED GLUCOCORTICOID LEVELS IN PFC MAY BE INVOLVED IN MEDIATING WORKING MEMORY IMPAIRMENTS AND NEUROADAPTIVE CHANGES DURING WITHDRAWAL FROM CHRONIC ALCOHOL INTAKE. IT THEN HIGHLIGHTS THE ROLE OF CAMP-PKA-CREB SIGNALING CASCADE AND HISTONE ACETYLATION WITHIN THE PFC AND LIMBIC STRUCTURES IN ALCOHOL-INDUCED ANXIETY AND BEHAVIORAL IMPAIRMENTS, AND HOW AN UNDERSTANDING OF FUNCTIONAL ALTERATIONS OF THESE PATHWAYS MIGHT LEAD TO BETTER TREATMENTS FOR NEUROPSYCHIATRIC DISORDERS. 2016 20 1803 21 EFFECT OF PROLONGED EMOTIONAL AND PAIN STRESS ON THE CONTENT OF METHYLCYTOSINE-BINDING PROTEIN MECP2 IN NUCLEI OF HIPPOCAMPAL NEURONS IN RATS WITH DIFFERENT EXCITABILITY OF THE NERVOUS SYSTEM. IN RATS WITH LOW EXCITABILITY THRESHOLD OF THE NERVOUS SYSTEM DEMONSTRATING SIGNIFICANT AND PERSISTENT BEHAVIORAL DISORDERS UNDER STRESS CONDITIONS, THE CONTENT OF METHYLCYTOSINE-BINDING PROTEIN MECP2 IN NEURONAL NUCLEI OF HIPPOCAMPAL FIELD CA3 DECREASED OVER 2 WEEKS AFTER LONG-TERM EMOTIONAL AND PAIN STRESS. IT WAS HYPOTHESIZED THAT PROTEIN MECP2 TRIGGERS EPIGENETIC CHANGES IN DNA THAT UNDERLIE "STRESS MEMORY". 2006