1 432 110 ANTIDEPRESSANT TREATMENT IS ASSOCIATED WITH EPIGENETIC ALTERATIONS IN THE PROMOTER OF P11 IN A GENETIC MODEL OF DEPRESSION. P11 (S100A10) HAS BEEN ASSOCIATED WITH THE PATHOPHYSIOLOGY OF DEPRESSION BOTH IN HUMAN AND RODENT MODELS. DIFFERENT TYPES OF ANTIDEPRESSANTS HAVE BEEN SHOWN TO INCREASE P11 LEVELS IN DISTINCT BRAIN REGIONS AND P11 GENE THERAPY WAS RECENTLY PROVEN EFFECTIVE IN REVERSING DEPRESSIVE-LIKE BEHAVIOURS IN MICE. HOWEVER, THE MOLECULAR MECHANISMS THAT GOVERN P11 GENE EXPRESSION IN RESPONSE TO ANTIDEPRESSANTS STILL REMAIN ELUSIVE. IN THIS STUDY WE REPORT DECREASED LEVELS OF P11, ASSOCIATED WITH HIGHER DNA METHYLATION IN THE PROMOTER REGION, IN THE PREFRONTAL CORTEX OF THE FLINDERS SENSITIVE LINE (FSL) GENETIC RODENT MODEL OF DEPRESSION. THIS HYPERMETHYLATED PATTERN WAS REVERSED TO NORMAL, AS INDICATED BY THE CONTROL LINE, AFTER CHRONIC ADMINISTRATION OF ESCITALOPRAM (A SELECTIVE SEROTONIN REUPTAKE INHIBITOR; SSRI). THE ESCITALOPRAM-INDUCED HYPOMETHYLATION WAS ASSOCIATED WITH BOTH AN INCREASE IN P11 GENE EXPRESSION AND A REDUCTION IN MRNA LEVELS OF TWO DNA METHYLTRANSFERASES THAT HAVE BEEN SHOWN TO MAINTAIN DNA METHYLATION IN ADULT FOREBRAIN NEURONS (DNMT1 AND DNMT3A). IN CONCLUSION, OUR DATA FURTHER SUPPORT A ROLE FOR P11 IN DEPRESSION-LIKE STATES AND SUGGEST THAT THIS GENE IS CONTROLLED BY EPIGENETIC MECHANISMS THAT CAN BE AFFECTED BY ANTIDEPRESSANT TREATMENT. 2012 2 583 26 BEHAVIORAL DIFFERENCES OF MALE WISTAR RATS FROM DIFFERENT VENDORS IN VULNERABILITY AND RESILIENCE TO CHRONIC MILD STRESS ARE REFLECTED IN EPIGENETIC REGULATION AND EXPRESSION OF P11. OUTBRED RAT LINES SUCH AS WISTAR RATS ARE COMMONLY USED FOR MODELS OF DEPRESSIVE DISORDERS. SUCH RATS ARISE FROM RANDOM MATING SCHEDULES. HENCE, GENETIC DRIFT OCCURS IN OUTBRED POPULATIONS WHICH COULD LEAD TO GENOTYPIC AND PHENOTYPIC HETEROGENEITY BETWEEN RATS FROM DIFFERENT VENDORS. ADDITIONALLY, VENDOR SPECIFIC REARING CONDITIONS COULD CONTRIBUTE TO INTRASTRAIN VARIABILITY. IN THE PRESENT STUDY DIFFERENCES IN BEHAVIORAL RESPONSES TO THE CHRONIC MILD STRESS (CMS) MODEL OF DEPRESSION WITHIN WISTAR RAT STRAINS FROM DIFFERENT VENDORS ARE DESCRIBED. DNA METHYLATION STUDIES AND MRNA EXPRESSION ANALYSIS OF P11 REVEALED THAT THE BEHAVIORAL DIFFERENCES BETWEEN THE SUBSTRAINS ARE REFLECTED AT THE EPIGENETIC AND GENETIC LEVEL. THE RESULTS SUGGEST THAT THERE ARE BREEDER-DEPENDENT DIFFERENCES IN VULNERABILITY TO STRESS IN THE CMS MODEL OF DEPRESSION, WHICH MIGHT BEAR ON THE VALIDITY OF THE MODEL AND CONTRIBUTE TO CONTRADICTORY FINDINGS AND DIFFICULTIES OF REPLICATION BETWEEN LABORATORIES. P11 MRNA EXPRESSION SEEMS TO BE DIFFERENTLY REGULATED DEPENDING ON THE QUALITY OF THE STRESS RESPONSE EVOKED BY CMS EXPOSURE. 2016 3 434 49 ANTIDEPRESSANT-LIKE EFFECT OF SODIUM BUTYRATE IS ASSOCIATED WITH AN INCREASE IN TET1 AND IN 5-HYDROXYMETHYLATION LEVELS IN THE BDNF GENE. BACKGROUND: EPIGENETIC DRUGS LIKE SODIUM BUTYRATE (NAB) SHOW ANTIDEPRESSANT-LIKE EFFECTS IN PRECLINICAL STUDIES, BUT THE EXACT MOLECULAR MECHANISMS OF THE ANTIDEPRESSANT EFFECTS REMAIN UNKNOWN. WHILE RESEARCH USING NAB HAS MAINLY FOCUSED ON ITS ROLE AS A HISTONE DEACETYLASE INHIBITOR (HDACI), THERE IS ALSO EVIDENCE THAT NAB AFFECTS DNA METHYLATION. METHODS: THE PURPOSE OF THIS STUDY WAS TO EXAMINE NAB'S PUTATIVE ANTIDEPRESSANT-LIKE EFFICACY IN RELATION TO DNA METHYLATION CHANGES IN THE PREFRONTAL CORTEX OF AN ESTABLISHED GENETIC RAT MODEL OF DEPRESSION (THE FLINDERS SENSITIVE LINE [FSL]) AND ITS CONTROLS (THE FLINDERS RESISTANT LINE). RESULTS: THE FSL RATS HAD LOWER LEVELS OF TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE 1 (TET1), WHICH CATALYZES THE CONVERSION OF DNA METHYLATION TO HYDROXYMETHYLATION. AS INDICATED BY THE BEHAVIORAL DESPAIR TEST, CHRONIC ADMINISTRATION OF NAB HAD ANTIDEPRESSANT-LIKE EFFECTS IN THE FSL AND WAS ACCOMPANIED BY INCREASED LEVELS OF TET1. THE TET1 UPREGULATION WAS ALSO ASSOCIATED WITH AN INCREASE OF HYDROXYMETHYLATION AND A DECREASE OF METHYLATION IN BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF), A GENE ASSOCIATED WITH NEUROGENESIS AND SYNAPTIC PLASTICITY. THESE EPIGENETIC CHANGES WERE ASSOCIATED WITH A CORRESPONDING BDNF OVEREXPRESSION. CONCLUSIONS: OUR DATA SUPPORT THE ANTIDEPRESSANT EFFICACY OF HDACIS AND SUGGEST THAT THEIR EPIGENETIC EFFECTS MAY ALSO INCLUDE DNA METHYLATION CHANGES THAT ARE MEDIATED BY DEMETHYLATION-FACILITATING ENZYMES LIKE TET1. 2014 4 6804 47 [EPIGENETIC REGULATION IN DEPRESSION]. RECENT RESEARCH HAS RAISED THE NOTION THAT EPIGENETIC MECHANISMS (E.G., DNA METHYLATION AND HISTONE MODIFICATIONS), WHICH EXERT LASTING CONTROL OVER GENE EXPRESSION WITHOUT ALTERING THE GENETIC CODE, COULD MEDIATE STABLE CHANGES IN BRAIN FUNCTION. HOWEVER, THE ROLE OF ENVIRONMENTAL FACTORS ALONG WITH GENETIC FACTORS IN THE EPIGENETIC REGULATION OF THE PATHOGENESIS OF DEPRESSION IS LARGELY UNKNOWN. TWO GENETICALLY DISTINCT MICE STRAINS, BALB/C (BALB) AND C57BL/6 (B6), EXHIBIT DIFFERENT BEHAVIORAL RESPONSES TO CHRONIC STRESS. WITH CHRONIC STRESS, BALB MICE SHOWED DEPRESSIVE-LIKE BEHAVIORS, BUT NOT B6 MICE, AND GLIAL CELL-DERIVED NEUROTROPHIC FACTOR (GDNF) EXPRESSION LEVEL WAS DECREASED IN THE VENTRAL STRIATUM OF BALB MICE BUT INCREASED IN B6 MICE. IN BALB MICE, DEPRESSIVE-LIKE BEHAVIORS AND DECREASED GDNF EXPRESSION WERE RECOVERED BY CHRONIC ANTIDEPRESSANT TREATMENT. THEREFORE, WE USED THESE TWO MICE STRAINS TO INVESTIGATE HOW THE EPIGENETIC STATUS OF THE GDNF GENE IN THE VENTRAL STRIATUM MODULATES STRESS VULNERABILITY. BOTH MICE STRAINS SHOWED INCREASED DNA METHYLATION LEVELS AND MECP2 RECRUITMENT IN THE GDNF PROMOTER REGION. HOWEVER, HISTONE H3 ACETYLATION LEVEL WAS DECREASED IN BALB MICE, BUT INCREASED IN B6 MICE. FURTHERMORE, BALB MICE SHOWED INCREASED HISTONE DEACETYLASE2 (HDAC2) EXPRESSION LEVEL AND RE-CHIP ASSAY REVEALED HDAC2-MECP2 COMPLEX IN BALB MICE. OUR RESULTS INDICATE THE CRUCIAL ROLE OF HISTONE MODIFICATION BY HDAC2 AND MECP2 COMPLEX FOR THE CONTROL OF GDNF EXPRESSION AND SUBSEQUENT BEHAVIORAL RESPONSES TO CHRONIC STRESS, IN OTHER WORDS, THE SUSCEPTIBILITY TO STRESS. IN ADDITION, WE INVESTIGATED THE EFFECT OF ANTIDEPRESSANTS ON THE EPIGENETIC REGULATION OF GDNF EXPRESSION. WE FOUND A REDUCED LEVEL OF HDAC4 RECRUITMENT AT THE GDNF PROMOTER REGION WITH ANTIDEPRESSANTS. THUS, OUR DATA SUGGEST THAT ANTIDEPRESSANTS INCREASE TRANSCRIPTIONAL ACTIVITY OF THE GDNF GENE THROUGH THE MODULATION OF HISTONE ACETYLATION BY HDAC4. FINALLY, WE EXAMINED THE EXPRESSIONS OF GDNF AND EPIGENETIC-RELATED MOLECULES MRNAS WITH MAJOR DEPRESSIVE AND BIPOLAR DISORDER PATIENTS BY USING QUANTITATIVE REAL-TIME PCR. WE FOUND THE ABERRANT EXPRESSION OF GDNF AND EPIGENETIC-RELATED GENES INCLUDING HDAC2 AND HDAC4 IN MOOD DISORDER PATIENTS. THUS, OUR DATA PROVIDE NOVEL INSIGHTS SUGGESTING THAT EPIGENETIC MECHANISMS OF GDNF EXPRESSION ARE INVOLVED IN THE PATHOGENESIS OR PATHOPHYSIOLOGY OF DEPRESSION. 2012 5 1808 43 EFFECTS OF ADOLESCENT SOCIAL STRESS AND ANTIDEPRESSANT TREATMENT ON COGNITIVE INFLEXIBILITY AND BDNF EPIGENETIC MODIFICATIONS IN THE MPFC OF ADULT MICE. ADOLESCENT SOCIAL STRESS (ASS) CAN INCREASE SUSCEPTIBILITY TO DEPRESSION IN ADULTHOOD. HOWEVER, THE UNDERLYING PSYCHOLOGICAL AND NEURAL MECHANISMS REMAIN UNCLEAR. CORTICALLY MEDIATED COGNITIVE DYSFUNCTIONS ARE INCREASINGLY RECOGNIZED AS AN INDEPENDENT AND IMPORTANT RISK FACTOR OF DEPRESSION. USING SOCIAL DEFEAT STRESS, A CLASSICAL ANIMAL MODEL OF DEPRESSION, OUR PREVIOUS STUDIES FOUND THAT MICE SUBJECTED TO THIS FORM OF STRESS DURING EARLY ADOLESCENCE DISPLAYED COGNITIVE INFLEXIBILITY (CI) IN ADULTHOOD. THIS CHANGE WAS ACCOMPANIED BY A DOWN-REGULATION OF BDNF GENE EXPRESSION IN THE MEDIAL PREFRONTAL CORTEX (MPFC); THIS GENE ENCODES A KEY MOLECULE INVOLVED IN DEPRESSION AND ANTIDEPRESSANT ACTION. IN THE PRESENT PAPER, WE IDENTIFIED EPIGENETIC MODIFICATION OF BDNF AS A POSSIBLE MECHANISM UNDERLYING THE BEHAVIORAL AND MOLECULAR CHANGES. ASS INDUCED A SET OF DEPRESSIVE PHENOTYPES, INCLUDING INCREASED SOCIAL AVOIDANCE AND CI, AS WELL AS REDUCED LEVELS OF TOTAL BDNF AND ISOFORM IV BUT NOT ISOFORM I OR VI TRANSCRIPTS IN THE MPFC. IN PARALLEL WITH CHANGES IN BDNF GENE EXPRESSION, PREVIOUSLY STRESSED ADULT MICE SHOWED INCREASED LEVELS OF DIMETHYLATION OF HISTONE H3 AT LYSINE K9 (H3K9ME2) IMMEDIATELY DOWNSTREAM OF THE BDNF IV PROMOTER. ON THE OTHER HAND, NO DIFFERENCES WERE FOUND IN TRIMETHYLATION OF HISTONE H3 AT LYSINE K4 (H3K4ME3) OR IN ACETYLATION OF HISTONE H3 AT LYSINE K9 (H3K9AC) OR AT K4 (H3K4AC) IN THE BDNF IV PROMOTER. LIKEWISE, NO ALTERATIONS WERE FOUND IN DNA METHYLATION OF THE BDNF IV PROMOTER. ADDITIONALLY, TREATMENT WITH THE CHRONIC ANTIDEPRESSANT TRANYLCYPROMINE REVERSED BDNF EPIGENETIC CHANGES AND RELATED GENE TRANSCRIPTION WHILE ALSO REVERSING CI, BUT NOT SOCIAL AVOIDANCE, IN PREVIOUSLY STRESSED ADULT MICE. THESE RESULTS SUGGEST THAT EPIGENETIC CHANGES TO THE BDNF GENE IN THE MPFC AFTER ADOLESCENT SOCIAL ADVERSITY MAY BE INVOLVED IN THE REGULATION OF COGNITIVE DYSFUNCTION IN DEPRESSION AND ANTIDEPRESSANT ACTION IN ADULTHOOD. 2018 6 3969 44 LONG-LASTING DEPRESSION-LIKE BEHAVIOR AND EPIGENETIC CHANGES OF BDNF GENE EXPRESSION INDUCED BY PERINATAL EXPOSURE TO METHYLMERCURY. SUBSTANTIAL EVIDENCE INDICATES THAT PREDISPOSITION TO DISEASES CAN BE ACQUIRED DURING EARLY STAGES OF DEVELOPMENT AND INTERACTIONS BETWEEN ENVIRONMENTAL AND GENETIC FACTORS MAY BE IMPLICATED IN THE ONSET OF MANY PATHOLOGICAL CONDITIONS. DATA COLLECTED OVER SEVERAL DECADES HAVE SHOWN THAT CHEMICALS ARE AMONG THE RELEVANT FACTORS THAT CAN ENDANGER CNS. WE PREVIOUSLY SHOWED THAT PERINATAL EXPOSURE TO METHYLMERCURY (MEHG) CAUSES PERSISTENT CHANGES IN LEARNING AND MOTIVATIONAL BEHAVIOR IN MICE. IN THIS STUDY, WE REPORT THAT THE DEPRESSION-LIKE BEHAVIOR IN MEHG-EXPOSED MALE MICE IS REVERSED BY CHRONIC TREATMENT WITH THE ANTIDEPRESSANT FLUOXETINE. BEHAVIORAL ALTERATIONS ARE ASSOCIATED WITH A DECREASE IN BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) MRNA IN THE HIPPOCAMPAL DENTATE GYRUS AND FLUOXETINE TREATMENT RESTORES BDNF MRNA EXPRESSION. WE ALSO SHOW THAT MEHG-EXPOSURE INDUCES LONG-LASTING REPRESSIVE STATE OF THE CHROMATIN STRUCTURE AT THE BDNF PROMOTER REGION, IN PARTICULAR DNA HYPERMETHYLATION, AN INCREASE IN HISTONE H3-K27 TRI-METHYLATION AND A DECREASE IN H3 ACETYLATION AT THE PROMOTER IV. WHILE FLUOXETINE TREATMENT DOES NOT ALTER HYPERMETHYLATION OF H3-K27, IT SIGNIFICANTLY UP-REGULATES H3 ACETYLATION AT THE BDNF PROMOTER IV IN MEHG-EXPOSED MICE. OUR STUDY SHOWS THAT DEVELOPMENTAL EXPOSURE TO LOW LEVELS OF MEHG PREDISPOSES MICE TO DEPRESSION AND INDUCES EPIGENETIC SUPPRESSION OF BDNF GENE EXPRESSION IN THE HIPPOCAMPUS. 2008 7 2740 29 EXPOSURE TO EARLY LIFE STRESS RESULTS IN EPIGENETIC CHANGES IN NEUROTROPHIC FACTOR GENE EXPRESSION IN A PARKINSONIAN RAT MODEL. EARLY LIFE ADVERSITY INCREASES THE RISK OF MENTAL DISORDERS LATER IN LIFE. CHRONIC EARLY LIFE STRESS MAY ALTER NEUROTROPHIC FACTOR GENE EXPRESSION INCLUDING THOSE FOR BRAIN DERIVED NEUROTROPHIC FACTOR (BDNF) AND GLIAL CELL DERIVED NEUROTROPHIC FACTOR (GDNF) THAT ARE IMPORTANT IN NEURONAL GROWTH, SURVIVAL, AND MAINTENANCE. MATERNAL SEPARATION WAS USED IN THIS STUDY TO MODEL EARLY LIFE STRESS. FOLLOWING UNILATERAL INJECTION OF A MILD DOSE OF 6-HYDROXYDOPAMINE (6-OHDA), WE MEASURED CORTICOSTERONE (CORT) IN THE BLOOD AND STRIATUM OF STRESSED AND NONSTRESSED RATS; WE ALSO MEASURED DNA METHYLATION AND BDNF AND GDNF GENE EXPRESSION IN THE STRIATUM USING REAL TIME PCR. IN THE PRESENCE OF STRESS, WE FOUND THAT THERE WAS INCREASED CORTICOSTERONE CONCENTRATION IN BOTH BLOOD AND STRIATAL TISSUE. FURTHER TO THIS, WE FOUND HIGHER DNA METHYLATION AND DECREASED NEUROTROPHIC FACTOR GENE EXPRESSION. 6-OHDA LESION INCREASED NEUROTROPHIC FACTOR GENE EXPRESSION IN BOTH STRESSED AND NONSTRESSED RATS BUT THIS INCREASE WAS HIGHER IN THE NONSTRESSED RATS. OUR RESULTS SUGGEST THAT EXPOSURE TO EARLY POSTNATAL STRESS INCREASES CORTICOSTERONE CONCENTRATION WHICH LEADS TO INCREASED DNA METHYLATION. THIS EFFECT RESULTS IN DECREASED BDNF AND GDNF GENE EXPRESSION IN THE STRIATUM LEADING TO DECREASED PROTECTION AGAINST SUBSEQUENT INSULTS LATER IN LIFE. 2016 8 5467 40 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 9 431 41 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 10 989 34 CHRONIC SOCIAL DEFEAT STRESS DIFFERENTIALLY REGULATES THE EXPRESSION OF BDNF TRANSCRIPTS AND EPIGENETIC MODIFYING ENZYMES IN SUSCEPTIBLE AND RESILIENT MICE. OBJECTIVES: ALTHOUGH STRESS IS CONSIDERED A PRIMARY RISK FACTOR FOR NEUROPSYCHIATRIC DISORDERS, A MAJORITY OF INDIVIDUALS ARE RESILIENT TO THE EFFECTS OF STRESS EXPOSURE AND SUCCESSFULLY ADAPT TO ADVERSE LIFE EVENTS, WHILE OTHERS, THE SO-CALLED SUSCEPTIBLE INDIVIDUALS, MAY HAVE PROBLEMS TO PROPERLY ADAPT TO ENVIRONMENTAL CHANGES. HOWEVER, THE MECHANISMS UNDERLYING THESE DIFFERENT RESPONSES TO STRESS EXPOSURE ARE POORLY UNDERSTOOD.METHODS: ADULT MALE C57BL/6J MICE WERE EXPOSED TO CHRONIC SOCIAL DEFEAT STRESS PROTOCOL AND LEVELS OF BRAIN DERIVED NEUROTROPHIC FACTOR (BDNF) TRANSCRIPTS AND EPIGENETIC MODIFYING ENZYMES WERE ANALYSED BY REAL-TIME PCR IN THE HIPPOCAMPUS (HPC) AND PREFRONTAL CORTEX (PFC) OF SUSCEPTIBLE AND RESILIENT MICE.RESULTS: WE FOUND A SELECTIVE REDUCTION OF BDNF-6 TRANSCRIPT IN THE HPC AND AN INCREASE OF BDNF-4 TRANSCRIPT IN THE PFC OF SUSCEPTIBLE MICE. MOREOVER, SUSCEPTIBLE MICE SHOWED A SELECTIVE REDUCTION OF THE G9A MRNA LEVELS IN THE HPC, WHILE HDAC-5 AND DNMT3A MRNA LEVELS WERE SPECIFICALLY REDUCED IN THE PFC.CONCLUSIONS: OVERALL, OUR RESULTS, SHOWING A DIFFERENT EXPRESSION OF BDNF TRANSCRIPTS AND EPIGENETIC MODIFYING ENZYMES IN SUSCEPTIBLE AND RESILIENT MICE, SUGGEST THAT STRESS RESILIENCE IS NOT SIMPLY A LACK OF ACTIVATION OF STRESS-RELATED PATHWAYS, BUT IS RELATED TO THE ACTIVATION OF ADDITIONAL DIFFERENT SPECIFIC MECHANISMS. 2019 11 1614 38 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 12 4173 30 MELATONIN INDUCES HISTONE HYPERACETYLATION IN THE RAT BRAIN. WE HAVE REPORTED THAT MELATONIN INDUCES HISTONE HYPERACETYLATION IN MOUSE NEURAL STEM CELLS, SUGGESTING AN EPIGENETIC ROLE FOR THIS PLEIOTROPIC HORMONE. TO SUPPORT SUCH A ROLE, IT IS NECESSARY TO DEMONSTRATE THAT MELATONIN PRODUCES SIMILAR EFFECTS IN VIVO. HISTONE ACETYLATION, FOLLOWING CHRONIC TREATMENT WITH MELATONIN (4MUG/ML IN DRINKING WATER FOR 17 DAYS), WAS EXAMINED BY WESTERN BLOTTING IN SELECTED RAT BRAIN REGIONS. MELATONIN INDUCED SIGNIFICANT INCREASES IN HISTONE H3 AND HISTONE H4 ACETYLATION IN THE HIPPOCAMPUS. HISTONE H4 WAS ALSO HYPERACETYLATED IN THE STRIATUM, BUT THERE WERE NO SIGNIFICANT CHANGES IN HISTONE H3 ACETYLATION IN THIS BRAIN REGION. NO SIGNIFICANT CHANGES IN THE ACETYLATION OF EITHER HISTONE H3 OR H4 WERE OBSERVED IN THE MIDBRAIN AND CEREBELLUM. AN EXAMINATION OF KINASE ACTIVATION, WHICH MAY BE RELATED TO THESE CHANGES, REVEALED THAT MELATONIN TREATMENT INCREASED THE LEVELS OF PHOSPHO-ERK (EXTRACELLULAR SIGNAL-REGULATED KINASE) IN THE HIPPOCAMPUS AND STRIATUM, BUT PHOSPHO-AKT (PROTEIN KINASE B) LEVELS WERE UNCHANGED. THESE FINDINGS SUGGEST THAT CHROMATIN REMODELING AND ASSOCIATED CHANGES IN THE EPIGENETIC REGULATION OF GENE EXPRESSION UNDERLIE THE MULTIPLE PHYSIOLOGICAL EFFECTS OF MELATONIN. 2013 13 345 46 ALTERED BRAIN EXPRESSION OF DNA METHYLATION AND HYDROXYMETHYLATION EPIGENETIC ENZYMES IN A RAT MODEL OF NEUROPATHIC PAIN. THE ROLE OF EPIGENETICS IN CHRONIC PAIN AT THE SUPRASPINAL LEVEL IS YET TO BE FULLY CHARACTERIZED. DNA HISTONE METHYLATION IS CRUCIALLY REGULATED BY DE NOVO METHYLTRANSFERASES (DNMT1-3) AND TEN-ELEVEN TRANSLOCATION DIOXYGENASES (TET1-3). EVIDENCE HAS SHOWN THAT METHYLATION MARKERS ARE ALTERED IN DIFFERENT CNS REGIONS RELATED TO NOCICEPTION, NAMELY THE DORSAL ROOT GANGLIA, THE SPINAL CORD, AND DIFFERENT BRAIN AREAS. DECREASED GLOBAL METHYLATION WAS FOUND IN THE DRG, THE PREFRONTAL CORTEX, AND THE AMYGDALA, WHICH WAS ASSOCIATED WITH DECREASED DNMT1/3A EXPRESSION. IN CONTRAST, INCREASED METHYLATION LEVELS AND MRNA LEVELS OF TET1 AND TET3 WERE LINKED TO AUGMENTED PAIN HYPERSENSITIVITY AND ALLODYNIA IN INFLAMMATORY AND NEUROPATHIC PAIN MODELS. SINCE EPIGENETIC MECHANISMS MAY BE RESPONSIBLE FOR THE REGULATION AND COORDINATION OF VARIOUS TRANSCRIPTIONAL MODIFICATIONS DESCRIBED IN CHRONIC PAIN STATES, WITH THIS STUDY, WE AIMED TO EVALUATE THE FUNCTIONAL ROLE OF TET1-3 AND DNMT1/3A GENES IN NEUROPATHIC PAIN IN SEVERAL BRAIN AREAS. IN A SPARED NERVE INJURY RAT MODEL OF NEUROPATHIC PAIN, 21 DAYS AFTER SURGERY, WE FOUND INCREASED TET1 EXPRESSION IN THE MEDIAL PREFRONTAL CORTEX AND DECREASED EXPRESSION IN THE CAUDATE-PUTAMEN AND THE AMYGDALA; TET2 WAS UPREGULATED IN THE MEDIAL THALAMUS; TET3 MRNA LEVELS WERE REDUCED IN THE MEDIAL PREFRONTAL CORTEX AND THE CAUDATE-PUTAMEN; AND DNMT1 WAS DOWNREGULATED IN THE CAUDATE-PUTAMEN AND THE MEDIAL THALAMUS. NO STATISTICALLY SIGNIFICANT CHANGES IN EXPRESSION WERE OBSERVED WITH DNMT3A. OUR RESULTS SUGGEST A COMPLEX FUNCTIONAL ROLE FOR THESE GENES IN DIFFERENT BRAIN AREAS IN THE CONTEXT OF NEUROPATHIC PAIN. THE NOTION OF DNA METHYLATION AND HYDROXYMETHYLATION BEING CELL-TYPE SPECIFIC AND NOT TISSUE SPECIFIC, AS WELL AS THE POSSIBILITY OF CHRONOLOGICALLY DIFFERENTIAL GENE EXPRESSION AFTER THE ESTABLISHMENT OF NEUROPATHIC OR INFLAMMATORY PAIN MODELS, OUGHT TO BE ADDRESSED IN FUTURE STUDIES. 2023 14 4299 28 MICRORNA-15B CONTRIBUTES TO DEPRESSION-LIKE BEHAVIOR IN MICE BY AFFECTING SYNAPTIC PROTEIN LEVELS AND FUNCTION IN THE NUCLEUS ACCUMBENS. MAJOR DEPRESSION IS A PREVALENT AFFECTIVE DISORDER CHARACTERIZED BY RECURRENT LOW MOOD. IT PRESUMABLY RESULTS FROM STRESS-INDUCED DETERIORATIONS OF MOLECULAR NETWORKS AND SYNAPTIC FUNCTIONS IN BRAIN REWARD CIRCUITS OF GENETICALLY-SUSCEPTIBLE INDIVIDUALS THROUGH EPIGENETIC PROCESSES. EPIGENETIC REGULATOR MICRORNA-15B INHIBITS NEURONAL PROGENITOR PROLIFERATION AND IS UP-REGULATED IN THE MEDIAL PREFRONTAL CORTEX OF MICE THAT DEMONSTRATE DEPRESSION-LIKE BEHAVIOR, INDICATING THE CONTRIBUTION OF MICRORNA-15 TO MAJOR DEPRESSION. USING A MOUSE MODEL OF MAJOR DEPRESSION INDUCED BY CHRONIC UNPREDICTABLE MILD STRESS (CUMS), HERE WE EXAMINED THE EFFECTS OF MICRORNA-15B ON SYNAPSES AND SYNAPTIC PROTEINS IN THE NUCLEUS ACCUMBENS OF THESE MICE. THE APPLICATION OF A MICRORNA-15B ANTAGOMIR INTO THE NUCLEUS ACCUMBENS SIGNIFICANTLY REDUCED THE INCIDENCE OF CUMS-INDUCED DEPRESSION AND REVERSED THE ATTENUATIONS OF EXCITATORY SYNAPSE AND SYNTAXIN-BINDING PROTEIN 3 (STXBP3A)/VESICLE-ASSOCIATED PROTEIN 1 (VAMP1) EXPRESSION. IN CONTRAST, THE INJECTION OF A MICRORNA-15B ANALOG INTO THE NUCLEUS ACCUMBENS INDUCED DEPRESSION-LIKE BEHAVIOR AS WELL AS ATTENUATED EXCITATORY SYNAPSES AND STXBP3A/VAMP1 EXPRESSION SIMILAR TO THE DOWN-REGULATION OF THESE PROCESSES INDUCED BY THE CUMS. WE CONCLUDE THAT MICRORNA-15B-5P MAY PLAY A CRITICAL ROLE IN CHRONIC STRESS-INDUCED DEPRESSION BY DECREASING SYNAPTIC PROTEINS, INNERVATIONS, AND ACTIVITIES IN THE NUCLEUS ACCUMBENS. WE PROPOSE THAT THE TREATMENT OF ANTI-MICRORNA-15B-5P MAY CONVERT STRESS-INDUCED DEPRESSION INTO RESILIENCE. 2020 15 213 35 ACUTE AND CHRONIC ELECTROCONVULSIVE SEIZURES (ECS) DIFFERENTIALLY REGULATE THE EXPRESSION OF EPIGENETIC MACHINERY IN THE ADULT RAT HIPPOCAMPUS. BACKGROUND: ELECTROCONVULSIVE SEIZURE TREATMENT IS A FAST-ACTING ANTIDEPRESSANT THERAPY THAT EVOKES RAPID TRANSCRIPTIONAL, NEUROGENIC, AND BEHAVIORAL CHANGES. EPIGENETIC MECHANISMS CONTRIBUTE TO ALTERED GENE REGULATION, WHICH UNDERLIES THE NEUROGENIC AND BEHAVIORAL EFFECTS OF ELECTROCONVULSIVE SEIZURE. WE HYPOTHESIZED THAT ELECTROCONVULSIVE SEIZURE MAY MODULATE THE EXPRESSION OF EPIGENETIC MACHINERY, THUS ESTABLISHING POTENTIAL ALTERATIONS IN THE EPIGENETIC LANDSCAPE. METHODS: WE EXAMINED THE INFLUENCE OF ACUTE AND CHRONIC ELECTROCONVULSIVE SEIZURE ON THE GENE EXPRESSION OF HISTONE MODIFIERS, NAMELY HISTONE ACETYLTRANSFERASES, HISTONE DEACETYLASES, HISTONE METHYLTRANSFERASES, AND HISTONE (LYSINE) DEMETHYLASES AS WELL AS DNA MODIFYING ENZYMES, INCLUDING DNA METHYLTRANSFERASES, DNA DEMETHYLASES, AND METHYL-CPG-BINDING PROTEINS IN THE HIPPOCAMPI OF ADULT MALE WISTAR RATS USING QUANTITATIVE REAL TIME-PCR ANALYSIS. FURTHER, WE EXAMINED THE INFLUENCE OF ACUTE AND CHRONIC ELECTROCONVULSIVE SEIZURE ON GLOBAL AND RESIDUE-SPECIFIC HISTONE ACETYLATION AND METHYLATION LEVELS WITHIN THE HIPPOCAMPUS, A BRAIN REGION IMPLICATED IN THE CELLULAR AND BEHAVIORAL EFFECTS OF ELECTROCONVULSIVE SEIZURE. RESULTS: ACUTE AND CHRONIC ELECTROCONVULSIVE SEIZURE INDUCED A PRIMARILY UNIQUE, AND IN CERTAIN CASES BIDIRECTIONAL, REGULATION OF HISTONE AND DNA MODIFIERS, AND METHYL-CPG-BINDING PROTEINS, WITH AN OVERLAPPING PATTERN OF GENE REGULATION RESTRICTED TO SIRT4, MLL3, JMJD3, GADD45B, TET2, AND TET3. GLOBAL HISTONE ACETYLATION AND METHYLATION LEVELS WERE PREDOMINANTLY UNCHANGED, WITH THE EXCEPTION OF A SIGNIFICANT DECLINE IN H3K9 ACETYLATION IN THE HIPPOCAMPUS FOLLOWING CHRONIC ELECTROCONVULSIVE SEIZURE. CONCLUSIONS: ELECTROCONVULSIVE SEIZURE TREATMENT EVOKES THE TRANSCRIPTIONAL REGULATION OF SEVERAL HISTONE AND DNA MODIFIERS, AND METHYL-CPG-BINDING PROTEINS WITHIN THE HIPPOCAMPUS, WITH A PREDOMINANTLY DISTINCT PATTERN OF REGULATION INDUCED BY ACUTE AND CHRONIC ELECTROCONVULSIVE SEIZURE. 2016 16 1418 42 DIFFERENCES IN DNA METHYLATION REPROGRAMMING UNDERLIE THE SEXUAL DIMORPHISM OF BEHAVIORAL DISORDER CAUSED BY PRENATAL STRESS IN RATS. PRENATAL STRESS (PS) CAN LEAD TO NEUROENDOCRINE AND EMOTIONAL DISORDERS LATER IN ADOLESCENCE. SEXUAL DIMORPHISM IN THESE NEURODEVELOPMENTAL OUTCOMES HAVE BEEN OBSERVED; HOWEVER, THE UNDERLYING MECHANISMS ARE NOT FULLY UNDERSTOOD. TO ADDRESS THIS ISSUE, WE INVESTIGATED WHETHER THERE ARE SEX DIFFERENCES IN EPIGENETIC REPROGRAMMING IN RATS EXPOSED TO PS. PREGNANT FEMALE RATS WERE SUBJECTED TO CHRONIC RESTRAINT STRESS FROM GESTATIONAL DAY (G)12 TO G18. FROM POSTNATAL DAY (P)38 TO P45, SUBGROUPS OF OFFSPRING INCLUDING BOTH MALES AND FEMALES WERE SUBJECTED TO BEHAVIORAL TESTING AND BRAIN TISSUE SPECIMENS WERE ANALYZED BY DNA PYROSEQUENCING, WESTERN BLOTTING, AND GOLGI STAINING TO ASSESS CHANGES IN METHYLATION PATTERN OF GLUCOCORTICOID RECEPTOR (GR) GENE, EXPRESSION OF DNA METHYLTRANSFERASE (DNMT) AND DNA DEMETHYLASE, AND DENDRITE MORPHOLOGY, RESPECTIVELY. THE DNA METHYLTRANSFERASE INHIBITOR DECITABINE WAS ADMINISTERED TO RATS PRIOR TO PS TO FURTHER EVALUATE THE ROLE OF METHYLATION IN THE SEXUALLY DIMORPHIC EFFECTS OF PS. THE RESULTS SHOWED THAT PS INCREASED ANXIETY-LIKE BEHAVIOR IN OFFSPRING, ESPECIALLY IN FEMALES, WHILE DEPRESSION-LIKE BEHAVIOR WAS INCREASED IN MALE OFFSPRING COMPARED TO CONTROL LITTERMATES. THE METHYLATION PATTERN IN THE PROMOTER REGION OF THE GR GENE DIFFERED BETWEEN MALES AND FEMALES. SEX-SPECIFIC CHANGES IN THE EXPRESSION OF DNMTS (DNMT1 AND DNMT3A) AND DNA DEMETHYLASE (TET METHYLCYTOSINE DIOXYGENASE 2) WERE ALSO OBSERVED. INTERESTINGLY, DECITABINE ALLEVIATED THE BEHAVIORAL DISORDER CAUSED BY PS AND RESTORED DENDRITE DENSITY AND MORPHOLOGY IN FEMALE BUT NOT MALE RATS. THESE FINDINGS SUGGEST THAT DIFFERENT CHANGE PATTERNS OF DNMT AND DEMETHYLASE IN THE TWO SEXES AFTER PS ARE RESPONSIBLE FOR THE SEXUALLY DIMORPHISM, WHICH COULD HAVE IMPLICATIONS FOR THE CLINICAL MANAGEMENT OF STRESS-RELATED DISORDERS. 2020 17 1740 30 EARLY ENRICHED ENVIRONMENT PREVENTS EPIGENETIC P11 GENE CHANGES INDUCED BY ADULTHOOD STRESS IN MICE. POSITIVE EXPERIENCES IN EARLY LIFE MAY IMPROVE THE CAPACITY TO COPE WITH ADULTHOOD STRESS THROUGH EPIGENETIC MODIFICATION. WE INVESTIGATED WHETHER AN ENRICHED ENVIRONMENT (EE) IN THE POSTNATAL PERIOD AFFECTED EPIGENETIC CHANGES IN THE P11 GENE INDUCED BY CHRONIC UNPREDICTABLE STRESS (CUS) IN ADULT C57BL/6J MICE. EE WAS INTRODUCED FOR 5 WEEKS DURING POSTNATAL DAYS 21-55. AFTER EE, THE MICE WERE SUBJECTED TO CUS FOR 4 WEEKS. EE PREVENTED DEPRESSION-LIKE BEHAVIOR INDUCED BY ADULT CUS. EE PREVENTED A DECREASE IN P11 MRNA AND HISTONE H3 ACETYLATION INDUCED BY CUS, WITH CHANGES IN THE EXPRESSION OF HISTONE DEACETYLASE 5. MOREOVER, EE PREVENTED CHANGES IN TRIMETHYLATION OF HISTONE H3 LYSINE 4 (H3K4) AND H3K27 INDUCED BY CUS. FURTHERMORE, EE HAD POSITIVE EFFECTS ON BEHAVIOR AND EPIGENETIC ALTERATIONS IN ADULT MICE WITHOUT CUS. THESE RESULTS SUGGEST THAT ONE OF THE UNDERLYING MECHANISMS OF EARLY-LIFE EE MAY INVOLVE EPIGENETIC MODIFICATION OF THE HIPPOCAMPAL P11 GENE PROMOTER. 2021 18 2152 40 EPIGENETIC MECHANISM OF 5-HT/NE/DA TRIPLE REUPTAKE INHIBITOR ON ADULT DEPRESSION SUSCEPTIBILITY IN EARLY STRESS MICE. MAJOR DEPRESSIVE DISORDER (MDD) IS A CHRONIC, REMITTING AND DEBILITATING DISEASE AND THE ETIOLOGY OF MDD IS HIGHLY COMPLICATED THAT INVOLVES GENETIC AND ENVIRONMENTAL INTERACTIONS. DESPITE MANY PHARMACOTHERAPEUTIC OPTIONS, MANY PATIENTS REMAIN POORLY TREATED AND THE DEVELOPMENT OF EFFECTIVE TREATMENTS REMAINS A HIGH PRIORITY IN THE FIELD. LPM570065 IS A POTENT 5-HYDROXYTRYPTAMINE (5-HT), NOREPINEPHRINE (NE) AND DOPAMINE (DA) TRIPLE REUPTAKE INHIBITOR AND BOTH PRECLINICAL AND CLINICAL RESULTS DEMONSTRATE SIGNIFICANT EFFICACY AGAINST MDD. THIS STUDY EXTENDS PREVIOUS FINDINGS TO EXAMINE THE EFFECTS AND UNDERLYING MECHANISMS OF LPM570065 ON STRESS VULNERABILITY USING A "TWO-HIT" STRESS MOUSE MODEL. THE "TWO-HIT" STRESS MODEL USED ADULT MICE THAT HAD EXPERIENCED EARLY LIFE MATERNAL SEPARATION (MS) STRESS FOR SOCIAL DEFEAT STRESS (SDS) AND THEN THEY WERE EVALUATED IN THREE BEHAVIORAL ASSAYS: SUCROSE PREFERENCE TEST, TAIL SUSPENSION TEST AND FORCED SWIMMING TEST. FOR THE MECHANISTIC STUDIES, METHYLATION-SPECIFIC DIFFERENTIALLY EXPRESSED GENES IN MOUSE HIPPOCAMPAL TISSUE AND VENTRAL TEGMENTAL AREA (VTA) WERE ANALYZED BY WHOLE-GENOME TRANSCRIPTOME ANALYSIS ALONG WITH NEXT-GENERATION BISULFITE SEQUENCING ANALYSIS, FOLLOWED BY RT-PCR AND PYROPHOSPHATE SEQUENCING TO CONFIRM GENE EXPRESSION AND METHYLATION. LPM570065 SIGNIFICANTLY REVERSED DEPRESSIVE-LIKE BEHAVIORS IN THE MICE IN THE SUCROSE PREFERENCE TEST, THE TAIL SUSPENSION TEST, AND THE FORCED SWIMMING TEST. MORPHOLOGICALLY, LPM570065 INCREASED THE DENSITY OF DENDRITIC SPINES IN HIPPOCAMPAL CA1 NEURONS. HYPERMETHYLATION AND DOWNREGULATION OF OXYTOCIN RECEPTOR (OXTR) IN THE HIPPOCAMPAL TISSUES ALONG WITH INCREASED PROTEIN EXPRESSION OF DNMT1 AND DNMT3A IN MICE THAT EXPERIENCED THE "TWO-HIT" STRESS COMPARED TO THOSE THAT ONLY EXPERIENCED ADULTHOOD SOCIAL DEFEAT STRESS, AND LPM570065 COULD REVERSE THESE CHANGES. COMBINED, THESE RESULTS SUGGEST THAT METHYLATION SPECIFICITY OF THE GENE OXTR IN THE HIPPOCAMPUS MAY PLAY AN IMPORTANT ROLE IN EARLY LIFE STRESS-INDUCED SUSCEPTIBILITY TO DEPRESSION AND THAT THE5-HT/NE/DA TRIPLE REUPTAKE INHIBITOR LPM570065 MAY REDUCE DEPRESSION SUSCEPTIBILITY VIA THE REVERSAL OF THE METHYLATION OF THE GENE OXTR. 2022 19 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 20 1809 31 EFFECTS OF ANTIPSYCHOTIC DRUGS ON THE EPIGENETIC MODIFICATION OF BRAIN-DERIVED NEUROTROPHIC FACTOR GENE EXPRESSION IN THE HIPPOCAMPI OF CHRONIC RESTRAINT STRESS RATS. RECENT STUDIES HAVE SHOWN THAT ANTIPSYCHOTIC DRUGS HAVE EPIGENETIC EFFECTS. HOWEVER, THE EFFECTS OF ANTIPSYCHOTIC DRUGS ON HISTONE MODIFICATION REMAIN UNCLEAR. THEREFORE, WE INVESTIGATED THE EFFECTS OF ANTIPSYCHOTIC DRUGS ON THE EPIGENETIC MODIFICATION OF THE BDNF GENE IN THE RAT HIPPOCAMPUS. RATS WERE SUBJECTED TO CHRONIC RESTRAINT STRESS (6 H/D FOR 21 D) AND THEN WERE ADMINISTERED WITH EITHER OLANZAPINE (2 MG/KG) OR HALOPERIDOL (1 MG/KG). THE LEVELS OF HISTONE H3 ACETYLATION AND MECP2 BINDING AT BDNF PROMOTER IV WERE ASSESSED WITH CHROMATIN IMMUNOPRECIPITATION ASSAYS. THE MRNA LEVELS OF TOTAL BDNF WITH EXON IV, HDAC5, DNMT1, AND DNMT3A WERE ASSESSED WITH A QUANTITATIVE RT-PCR PROCEDURE. CHRONIC RESTRAINT STRESS RESULTED IN THE DOWNREGULATION OF TOTAL AND EXON IV BDNF MRNA LEVELS AND A DECREASE IN HISTONE H3 ACETYLATION AND AN INCREASE IN MECP2 BINDING AT BDNF PROMOTER IV. FURTHERMORE, THERE WERE ROBUST INCREASES IN THE EXPRESSION OF HDAC5 AND DNMTS. OLANZAPINE ADMINISTRATION LARGELY PREVENTED THESE CHANGES. THE ADMINISTRATION OF HALOPERIDOL HAD NO EFFECT. THESE FINDINGS SUGGEST THAT THE ANTIPSYCHOTIC DRUG OLANZAPINE INDUCED HISTONE MODIFICATION OF BDNF GENE EXPRESSION IN THE HIPPOCAMPUS AND THAT THESE EPIGENETIC ALTERATIONS MAY REPRESENT ONE OF THE MECHANISMS UNDERLYING THE ACTIONS OF ANTIPSYCHOTIC DRUGS. 2018