1 69 132 A MEDIAL PREFRONTAL CORTEX-NUCLEUS ACUMENS CORTICOTROPIN-RELEASING FACTOR CIRCUITRY FOR NEUROPATHIC PAIN-INCREASED SUSCEPTIBILITY TO OPIOID REWARD. RECENT STUDIES HAVE SHOWN THAT PERSISTENT PAIN FACILITATES THE RESPONSE TO MORPHINE REWARD. HOWEVER, THE CIRCUIT MECHANISM UNDERLYING THIS PROCESS REMAINS AMBIGUOUS. IN THIS STUDY, USING CHRONIC CONSTRICTION INJURY (CCI) OF THE SCIATIC NERVE IN MICE, WE FOUND THAT PERSISTENT NEUROPATHIC PAIN REDUCED THE MINIMUM NUMBER OF MORPHINE CONDITIONING SESSIONS REQUIRED TO INDUCE CONDITIONED PLACE PREFERENCE (CPP) BEHAVIOR. THIS DOSE OF MORPHINE HAD NO EFFECT ON THE PAIN THRESHOLD. IN THE MEDIAL PREFRONTAL CORTEX (MPFC), WHICH IS INVOLVED IN BOTH PAIN AND EMOTION PROCESSING, CORTICOTROPIN-RELEASING FACTOR (CRF) EXPRESSING NEURONAL ACTIVITY WAS INCREASED IN CCI MICE. CHEMOGENETIC INHIBITION OF MPFC CRF NEURONS REVERSED CCI-INDUCED MORPHINE CPP FACILITATION. FURTHERMORE, THE NUCLEUS ACUMENS (NAC) RECEIVED MPFC CRF FUNCTIONAL PROJECTIONS THAT EXERTED EXCITATORY EFFECTS ON NAC NEURONS. OPTOGENETIC INHIBITION OF MPCF NEURONAL TERMINALS OR LOCAL INFUSION OF THE CRF RECEPTOR 1 (CRFR1) ANTAGONIST IN THE NAC RESTORED THE EFFECTS OF NEUROPATHIC PAIN ON MORPHINE-INDUCED CPP BEHAVIOR, BUT NOT IN NORMAL MICE. ON A MOLECULAR LEVEL, IN CCI MICE, CRFR1 PROTEIN EXPRESSION WAS INCREASED IN THE NAC BY A HISTONE DIMETHYLTRANSFERASE G9A-MEDIATED EPIGENETIC MECHANISM. LOCAL G9A KNOCKDOWN INCREASED THE EXPRESSION OF CRFR1 AND MIMICKED CCI-INDUCED HYPERSENSITIVITY TO ACQUIRING MORPHINE CPP. TAKEN TOGETHER, THESE FINDINGS DEMONSTRATE A PREVIOUSLY UNKNOWN AND SPECIFIC MPFC CRF ENGAGEMENT OF NAC NEURONAL CIRCUITS, THE SENSITIZATION OF WHICH FACILITATES BEHAVIORAL RESPONSES TO MORPHINE REWARD IN NEUROPATHIC PAIN STATES VIA CRFR1S. 2018 2 5749 31 SOCIAL DEFEAT INDUCES CHANGES IN HISTONE ACETYLATION AND EXPRESSION OF HISTONE MODIFYING ENZYMES IN THE VENTRAL HIPPOCAMPUS, PREFRONTAL CORTEX, AND DORSAL RAPHE NUCLEUS. CHRONIC EXPOSURE TO STRESS IS ASSOCIATED WITH A NUMBER OF PSYCHIATRIC DISORDERS, BUT LITTLE IS KNOWN ABOUT THE EPIGENETIC MECHANISMS THAT UNDERLIE THE STRESS RESPONSE OR RESILIENCE TO CHRONIC STRESS. WE INVESTIGATED HISTONE ACETYLATION IN SEVEN DIFFERENT BRAIN REGIONS OF RATS EXPOSED TO CHRONIC SOCIAL DEFEAT STRESS: THE DORSAL HIPPOCAMPUS (DHPC), VENTRAL HIPPOCAMPUS (VHPC), MEDIAL PREFRONTAL CORTEX (MPFC), BASOLATERAL AMYGDALA (BLA), LOCUS COERULEUS (LC), PARAVENTRICULAR THALAMUS (PVT), AND DORSAL RAPHE (DR) NUCLEUS. THIS STRESS PARADIGM WAS UNIQUE IN THAT IT ALLOWED RATS TO DISPLAY RESILIENCE IN THE FORM OF AN ACTIVE COPING MECHANISM. WE FOUND THAT THERE WAS AN INCREASE IN ACETYLATION OF H3K9/14 (H3K9/14AC) AND BULK ACETYLATION OF H4K5,8,12,16 (H4K5,8,12,16AC) IN THE DR NUCLEUS OF RATS THAT WERE LESS RESILIENT. LESS RESILIENT RATS ALSO DISPLAYED INCREASED LEVELS OF H3K18 ACETYLATION (H3K18AC) IN THE MPFC WHEN COMPARED TO NON-STRESSED CONTROLS. IN THE VHPC, THERE WAS AN INCREASE IN H3K18AC AND H4K12 (H4K12AC) IN RATS THAT WERE LESS RESILIENT WHEN COMPARED TO NON-STRESSED CONTROL RATS. IN ADDITION, THERE WAS A DECREASE IN LEVELS OF H4K8 ACETYLATION (H4K8AC) IN BOTH RESILIENT AND NON-RESILIENT RATS AS COMPARED TO CONTROLS. WE ASSESSED EXPRESSION OF HISTONE MODIFYING ENZYMES IN THE VHPC AND THE MPFC USING QUANTITATIVE REAL-TIME POLYMERASE CHAIN REACTION (PCR) AND FOUND CHANGES IN EXPRESSION OF A NUMBER OF TARGETS. THESE INCLUDED CHANGES IN SIRT1 AND SIRT2 IN THE VHPC AND CHANGES IN KAT5 IN THE MPFC. OVERALL, THESE RESULTS SUGGEST THAT CHANGES IN HISTONE ACETYLATION AND EXPRESSION OF HISTONE MODIFYING ENZYMES IN THESE REGIONS CORRELATE WITH THE BEHAVIORAL RESPONSE TO STRESS IN SOCIALLY DEFEATED RATS. 2014 3 3177 37 H3K9ME2 REGULATION OF BDNF EXPRESSION IN THE HIPPOCAMPUS AND MEDIAL PREFRONTAL CORTEX IS INVOLVED IN THE DEPRESSIVE-LIKE PHENOTYPE INDUCED BY MATERNAL SEPARATION IN MALE RATS. BACKGROUND: EARLY LIFE STRESS (ELS) INDUCES A DEPRESSIVE-LIKE PHENOTYPE AND INCREASES THE RISK OF DEPRESSION. BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) HAS BEEN CONFIRMED TO BE INVOLVED IN THE PATHOPHYSIOLOGY OF DEPRESSION. HOWEVER, THE MECHANISM BY WHICH ELS ALTERS THE EPIGENETIC REGULATION OF BDNF AND CHANGES SUSCEPTIBILITY TO DEPRESSION HAS NOT BEEN FULLY CLARIFIED. METHODS: THE PRESENT STUDY USED MATERNAL SEPARATION (MS) AND CHRONIC UNPREDICTED MILD STRESS (CUMS) TO ESTABLISH AN MS ANIMAL MODEL AND A DEPRESSIVE ANIMAL MODEL. WE ASSESSED DEPRESSIVE-LIKE BEHAVIOURS, INCLUDING ANHEDONIA, LOCOMOTOR ACTIVITY, ANXIETY-LIKE BEHAVIOUR, AND SPATIAL MEMORY, USING THE SUCROSE PREFERENCE TEST, THE OPEN FIELD TEST, THE ELEVATED PLUS MAZE TEST, AND THE MORRIS WATER MAZE TEST. WE ALSO INVESTIGATED BDNF AND H3K9ME2 EXPRESSION IN THE HIPPOCAMPUS AND MEDIAL PREFRONTAL CORTEX (MPFC) BY IMMUNOHISTOCHEMISTRY, WESTERN BLOTTING, AND QPCR ANALYSIS. ADDITIONALLY, WE USED UNC0642, A SMALL MOLECULE INHIBITOR OF HISTONE METHYLTRANSFERASE (G9A), AS AN INTERVENTION. RESULTS: THE RESULTS SHOWED THAT CUMS INDUCED DEPRESSIVE-LIKE BEHAVIOURS IN RATS AND RESULTED IN INCREASED H3K9ME2 EXPRESSION AND DECREASED BDNF EXPRESSION IN THE HIPPOCAMPUS AND MPFC. MORE IMPORTANTLY, ADULT MS RATS EXPERIENCING CUMS HAD MORE SEVERE DEPRESSIVE BEHAVIOURS, HAD HIGHER EXPRESSION OF H3K9ME2 IN THE HIPPOCAMPUS AND MPFC, AND HAD LOWER EXPRESSION OF BDNF IN THE HIPPOCAMPUS AND MPFC. IN ADDITION, ADMINISTRATION OF THE G9A INHIBITOR REVERSED MOST OF THE CHANGES. CONCLUSIONS: OUR STUDY SUGGESTS THAT ELS CHANGED BDNF AND H3K9ME2 EXPRESSION IN THE RAT BRAIN, RESULTING IN A DEPRESSIVE-LIKE PHENOTYPE. 2021 4 4218 43 METHYL SUPPLEMENTATION ATTENUATES COCAINE-SEEKING BEHAVIORS AND COCAINE-INDUCED C-FOS ACTIVATION IN A DNA METHYLATION-DEPENDENT MANNER. EPIGENETIC MECHANISMS, SUCH AS HISTONE MODIFICATIONS, REGULATE RESPONSIVENESS TO DRUGS OF ABUSE, SUCH AS COCAINE, BUT RELATIVELY LITTLE IS KNOWN ABOUT THE REGULATION OF ADDICTIVE-LIKE BEHAVIORS BY DNA METHYLATION. TO INVESTIGATE THE INFLUENCE OF DNA METHYLATION ON THE LOCOMOTOR-ACTIVATING EFFECTS OF COCAINE AND ON DRUG-SEEKING BEHAVIOR, RATS RECEIVING METHYL SUPPLEMENTATION VIA CHRONIC L-METHIONINE (MET) UNDERWENT EITHER A SENSITIZATION REGIMEN OF INTERMITTENT COCAINE INJECTIONS OR INTRAVENOUS SELF-ADMINISTRATION OF COCAINE, FOLLOWED BY CUE-INDUCED AND DRUG-PRIMED REINSTATEMENT. MET BLOCKED SENSITIZATION TO THE LOCOMOTOR-ACTIVATING EFFECTS OF COCAINE AND ATTENUATED DRUG-PRIMED REINSTATEMENT, WITH NO EFFECT ON CUE-INDUCED REINSTATEMENT OR SUCROSE SELF-ADMINISTRATION AND REINSTATEMENT. FURTHERMORE, UPREGULATION OF DNA METHYLTRANSFERASE 3A AND 3B AND GLOBAL DNA HYPOMETHYLATION WERE OBSERVED IN THE NUCLEUS ACCUMBENS CORE (NAC), BUT NOT IN THE MEDIAL PREFRONTAL CORTEX (MPFC), OF COCAINE-PRETREATED RATS. GLUTAMATERGIC PROJECTIONS FROM THE MPFC TO THE NAC ARE CRITICALLY INVOLVED IN THE REGULATION OF COCAINE-PRIMED REINSTATEMENT, AND ACTIVATION OF BOTH BRAIN REGIONS IS SEEN IN HUMAN ADDICTS WHEN REEXPOSED TO THE DRUG. WHEN COMPARED WITH VEHICLE-PRETREATED RATS, THE IMMEDIATE EARLY GENE C-FOS (A MARKER OF NEURONAL ACTIVATION) WAS UPREGULATED IN THE NAC AND MPFC OF COCAINE-PRETREATED RATS AFTER COCAINE-PRIMED REINSTATEMENT, AND CHRONIC MET TREATMENT BLOCKED ITS INDUCTION IN BOTH REGIONS. COCAINE-INDUCED C-FOS EXPRESSION IN THE NAC WAS ASSOCIATED WITH REDUCED METHYLATION AT CPG DINUCLEOTIDES IN THE C-FOS GENE PROMOTER, EFFECTS REVERSED BY MET TREATMENT. OVERALL, THESE DATA SUGGEST THAT DRUG-SEEKING BEHAVIORS ARE, IN PART, ATTRIBUTABLE TO A DNA METHYLATION-DEPENDENT PROCESS, LIKELY OCCURRING AT SPECIFIC GENE LOCI (E.G., C-FOS) IN THE REWARD PATHWAY. 2015 5 6095 39 THE EFFECTS OF SINGLE-DOSE INJECTIONS OF MODAFINIL AND METHAMPHETAMINE ON EPIGENETIC AND FUNCTIONAL MARKERS IN THE MOUSE MEDIAL PREFRONTAL CORTEX: POTENTIAL ROLE OF DOPAMINE RECEPTORS. METH USE CAUSES NEUROADAPTATIONS THAT NEGATIVELY IMPACT THE PREFRONTAL CORTEX (PFC) LEADING TO ADDICTION AND ASSOCIATED COGNITIVE DECLINE IN ANIMALS AND HUMANS. IN CONTRAST, MODAFINIL ENHANCES COGNITION BY INCREASING PFC FUNCTION. ACCUMULATED EVIDENCE INDICATES THAT PSYCHOSTIMULANT DRUGS, INCLUDING MODAFINIL AND METH, REGULATE GENE EXPRESSION VIA EPIGENETIC MODIFICATIONS. IN THIS STUDY, WE MEASURED THE EFFECTS OF SINGLE-DOSE INJECTIONS OF MODAFINIL AND METH ON THE PROTEIN LEVELS OF ACETYLATED HISTONE H3 (H3AC) AND H4AC, DEACETYLASES HDAC1 AND HDAC2, AND OF THE NMDA SUBUNIT GLUN1 IN THE MEDIAL PFC (MPFC) OF MICE EUTHANIZED 1 H AFTER DRUG ADMINISTRATION. TO TEST IF DOPAMINE (DA) RECEPTORS (DRS) PARTICIPATE IN THE BIOCHEMICAL EFFECTS OF THE TWO DRUGS, WE INJECTED THE D1RS ANTAGONIST, SCH23390, OR THE D2RS ANTAGONIST, RACLOPRIDE, 30 MIN BEFORE ADMINISTRATION OF METH AND MODAFINIL. WE EVALUATED EACH DRUG EFFECT ON GLUTAMATE SYNAPTIC TRANSMISSION IN D1R-EXPRESSING LAYER V PYRAMIDAL NEURONS. WE ALSO MEASURED THE ENRICHMENT OF H3AC AND H4AC AT THE PROMOTERS OF SEVERAL GENES INCLUDING DA, NE, OREXIN, HISTAMINE, AND GLUTAMATE RECEPTORS, AND THEIR MRNA EXPRESSION, SINCE THEY ARE RESPONSIVE TO CHRONIC MODAFINIL AND METH TREATMENT. ACUTE MODAFINIL AND METH INJECTIONS CAUSED SIMILAR EFFECTS ON TOTAL HISTONE ACETYLATION, INCREASING H3AC AND DECREASING H4AC, AND THEY ALSO INCREASED HDAC1, HDAC2 AND GLUN1 PROTEIN LEVELS IN THE MOUSE MPFC. IN ADDITION, THE EFFECTS OF THE DRUGS WERE PREVENTED BY PRE-TREATMENT WITH D1RS AND D2RS ANTAGONISTS. SPECIFICALLY, THE CHANGES IN H4AC, HDAC2, AND GLUN1 WERE RESPONSIVE TO SCH23390, WHEREAS THOSE OF H3AC AND GLUN1 WERE RESPONSIVE TO RACLOPRIDE. WHOLE-CELL PATCH CLAMP IN TRANSGENIC BAC-DRD1A-TDTOMATO MICE SHOWED THAT METH, BUT NOT MODAFINIL, INDUCED PAIRED-PULSE FACILITATION OF EPSCS, SUGGESTING REDUCED PRESYNAPTIC PROBABILITY OF GLUTAMATE RELEASE ONTO LAYER V PYRAMIDAL NEURONS. ANALYSIS OF HISTONE 3/4 ENRICHMENT AT SPECIFIC PROMOTERS REVEALED: I) DISTINCT EFFECTS OF THE DRUGS ON HISTONE 3 ACETYLATION, WITH MODAFINIL INCREASING H3AC AT DRD1 AND ADRA1B PROMOTERS, BUT METH INCREASING H3AC AT ADRA1A; II) DISTINCT EFFECTS ON HISTONE 4 ACETYLATION ENRICHMENT, WITH MODAFINIL INCREASING H4AC AT THE DRD2 PROMOTER AND DECREASING IT AT HRH1, BUT METH INCREASING H4AC AT DRD1; III) COMPARABLE EFFECTS OF BOTH PSYCHOSTIMULANTS, INCREASING H3AC AT DRD2, HCRTR1, AND HRH1 PROMOTERS, DECREASING H3AC AT HRH3, INCREASING H4AC AT HCRTR1, AND DECREASING H4AC AT HCRTR2, HRH3, AND GRIN1 PROMOTERS. INTERESTINGLY, ONLY METH ALTERED MRNA LEVELS OF GENES WITH ALTERED HISTONE ACETYLATION STATUS, INDUCING INCREASED EXPRESSION OF DRD1A, ADRA1A, HCRTR1, AND HRH1, AND DECREASING GRIN1. OUR STUDY SUGGESTS THAT ALTHOUGH ACUTE METH AND MODAFINIL CAN BOTH INCREASE DA NEUROTRANSMISSION IN THE MPFC, THERE ARE SIMILAR AND CONTRASTING EPIGENETIC AND TRANSCRIPTIONAL CONSEQUENCES THAT MAY ACCOUNT FOR THEIR DIVERGENT CLINICAL EFFECTS. 2019 6 4397 40 MODULATION OF DNA METHYLATION AND GENE EXPRESSION IN RODENT CORTICAL NEUROPLASTICITY PATHWAYS EXERTS RAPID ANTIDEPRESSANT-LIKE EFFECTS. BACKGROUND: STRESS INCREASES DNA METHYLATION, PRIMARILY A SUPPRESSIVE EPIGENETIC MECHANISM CATALYZED BY DNA METHYLTRANSFERASES (DNMT), AND DECREASES THE EXPRESSION OF GENES INVOLVED IN NEURONAL PLASTICITY AND MOOD REGULATION. DESPITE CHRONIC ANTIDEPRESSANT TREATMENT DECREASES STRESS-INDUCED DNA METHYLATION, IT IS NOT KNOWN WHETHER INHIBITION OF DNMT WOULD CONVEY RAPID ANTIDEPRESSANT-LIKE EFFECTS. AIM: THIS WORK TESTED SUCH A HYPOTHESIS AND EVALUATED WHETHER A BEHAVIORAL EFFECT INDUCED BY DNMT INHIBITORS (DNMTI) CORRESPONDS WITH CHANGES IN DNA METHYLATION AND TRANSCRIPT LEVELS IN GENES CONSISTENTLY ASSOCIATED WITH THE NEUROBIOLOGY OF DEPRESSION AND SYNAPTIC PLASTICITY (BDNF, TRKB, 5-HT(1A), NMDA, AND AMPA). METHODS: MALE WISTAR RATS RECEIVED INTRAPERITONEAL (I.P.) INJECTION OF TWO PHARMACOLOGICALLY DIFFERENT DNMTI (5-AZAD 0.2 AND 0.6 MG/KG OR RG108 0.6 MG/KG) OR VEHICLE (1 ML/KG), 1 H OR 7 DAYS BEFORE THE LEARNED HELPLESSNESS TEST (LH). DNA METHYLATION IN TARGET GENES AND THE CORRESPONDENT TRANSCRIPT LEVELS WERE MEASURED IN THE HIPPOCAMPUS (HPC) AND PREFRONTAL CORTEX (PFC) USING MEDIP-QPCR. IN PARALLEL SEPARATE GROUPS, THE ANTIDEPRESSANT-LIKE EFFECT OF 5-AZAD AND RG108 WAS INVESTIGATED IN THE FORCED SWIMMING TEST (FST). THE INVOLVEMENT OF CORTICAL BDNF-TRKB-MTOR PATHWAYS WAS ASSESSED BY INTRA-VENTRAL MEDIAL PFC (VMPFC) INJECTIONS OF RAPAMYCIN (MTOR INHIBITOR), K252A (TRKB RECEPTOR ANTAGONIST), OR VEHICLE (0.2 MUL/SIDE). RESULTS: WE FOUND THAT BOTH 5-AZAD AND RG108 ACUTELY AND 7 DAYS BEFORE THE TEST DECREASED ESCAPE FAILURES IN THE LH. LH STRESS INCREASED DNA METHYLATION AND DECREASED TRANSCRIPT LEVELS OF BDNF IV AND TRKB IN THE PFC, EFFECTS THAT WERE NOT SIGNIFICANTLY ATTENUATED BY RG108 TREATMENT. THE SYSTEMIC ADMINISTRATION OF 5-AZAD (0.2 MG/KG) AND RG108 (0.2 MG/KG) INDUCED AN ANTIDEPRESSANT-LIKE EFFECT IN FST, WHICH WAS, HOWEVER, ATTENUATED BY TRKB AND MTOR INHIBITION INTO THE VMPFC. CONCLUSION: THESE FINDINGS SUGGEST THAT ACUTE INHIBITION OF STRESS-INDUCED DNA METHYLATION PROMOTES RAPID AND SUSTAINED ANTIDEPRESSANT EFFECTS ASSOCIATED WITH INCREASED BDNF-TRKB-MTOR SIGNALING IN THE PFC. 2021 7 5443 34 REPEATED METHAMPHETAMINE AND MODAFINIL INDUCE DIFFERENTIAL COGNITIVE EFFECTS AND SPECIFIC HISTONE ACETYLATION AND DNA METHYLATION PROFILES IN THE MOUSE MEDIAL PREFRONTAL CORTEX. METHAMPHETAMINE (METH) AND MODAFINIL ARE PSYCHOSTIMULANTS WITH DIFFERENT LONG-TERM COGNITIVE PROFILES: METH IS ADDICTIVE AND LEADS TO COGNITIVE DECLINE, WHEREAS MODAFINIL HAS LITTLE ABUSE LIABILITY AND IS A COGNITIVE ENHANCER. INCREASING EVIDENCE IMPLICATES EPIGENETIC MECHANISMS OF GENE REGULATION BEHIND THE LASTING CHANGES THAT DRUGS OF ABUSE AND OTHER PSYCHOTROPIC COMPOUNDS INDUCE IN THE BRAIN, LIKE THE CONTROL OF GENE EXPRESSION BY HISTONES 3 AND 4 TAILS ACETYLATION (H3AC AND H4AC) AND DNA CYTOSINE METHYLATION (5-MC). MICE WERE TREATED WITH A SEVEN-DAY REPEATED METH, MODAFINIL OR VEHICLE PROTOCOL AND EVALUATED IN THE NOVEL OBJECT RECOGNITION (NOR) TEST OR SACRIFICED 4DAYS AFTER LAST INJECTION FOR MOLECULAR ASSAYS. WE EVALUATED TOTAL H3AC, H4AC AND 5-MC LEVELS IN THE MEDIAL PREFRONTAL CORTEX (MPFC), H3AC AND H4AC PROMOTOR ENRICHMENT (CHIP) AND MRNA EXPRESSION (RT-PCR) OF NEUROTRANSMITTER SYSTEMS INVOLVED IN AROUSAL, WAKEFULNESS AND COGNITIVE CONTROL, LIKE DOPAMINERGIC (DRD1 AND DRD2), ALPHA-ADRENERGIC (ADRA1A AND ADRA1B), OREXINERGIC (HCRTR1 AND HCRTR2), HISTAMINERGIC (HRH1 AND HRH3) AND GLUTAMATERGIC (AMPA GRIA1 AND NMDA GRIN1) RECEPTORS. REPEATED METH AND MODAFINIL TREATMENT ELICITED DIFFERENT COGNITIVE OUTCOMES IN THE NOR TEST, WHERE MODAFINIL-TREATED MICE PERFORMED AS CONTROLS AND METH-TREATED MICE SHOWED IMPAIRED RECOGNITION MEMORY. METH-TREATED MICE ALSO SHOWED I) DECREASED LEVELS OF TOTAL H3AC AND H4AC, AND INCREASED LEVELS OF 5-MC, II) DECREASED H3AC ENRICHMENT AT PROMOTERS OF DRD2, HCRTR1/2, HRH1 AND GRIN1, AND INCREASED H4AC ENRICHMENT AT DRD1, HRH1 AND GRIN1, III) INCREASED MRNA OF DRD1A, GRIN1 AND GRIA1. MODAFINIL-TREATED MICE SHARED NONE OF THESE EFFECTS AND SHOWED INCREASED H3AC ENRICHMENT AND MRNA EXPRESSION AT ADRA1B. MODAFINIL AND METH SHOWED SIMILAR EFFECTS LINKED TO DECREASED H3AC IN HRH3, INCREASED H4AC IN HCRTR1, AND DECREASED MRNA EXPRESSION OF HCRTR2. THE SPECIFIC METH-INDUCED EPIGENETIC AND TRANSCRIPTIONAL CHANGES DESCRIBED HERE MAY BE RELATED TO THE LONG-TERM COGNITIVE DECLINE EFFECTS OF THE DRUG AND ITS DETRIMENTAL EFFECTS ON MPFC FUNCTION. THE LACK OF SIMILAR EPIGENETIC EFFECTS OF CHRONIC MODAFINIL ADMINISTRATION SUPPORTS THIS NOTION. 2018 8 893 41 CHRONIC ETHANOL EXPOSURE AND WITHDRAWAL IMPAIR SYNAPTIC GABA(A) RECEPTOR-MEDIATED NEUROTRANSMISSION IN DEEP-LAYER PREFRONTAL CORTEX. BACKGROUND: THE PREFRONTAL CORTEX (PFC) ACTS AS AN INTEGRATIVE HUB FOR THE PROCESSING OF CORTICAL AND SUBCORTICAL INPUT INTO MEANINGFUL EFFERENT SIGNALING, PERMITTING COMPLEX ASSOCIATIVE BEHAVIORS. PFC DYSFUNCTION IS CONSISTENTLY OBSERVED WITH ETHANOL (ETOH) DEPENDENCE AND IS A CORE COMPONENT OF THE PATHOLOGY OF ALCOHOL USE DISORDERS IN CURRENT MODELS OF ADDICTION. WHILE INTRACORTICAL GAMMA-AMINOBUTRYRIC ACID (GABA)ERGIC NEUROTRANSMISSION IS UNDERSTOOD TO BE ESSENTIAL FOR MAINTAINING COORDINATED NETWORK ACTIVITY WITHIN THE CORTEX, RELATIVELY LITTLE IS KNOWN REGARDING FUNCTIONAL GABAERGIC ADAPTATIONS IN PFC DURING ETOH DEPENDENCE. METHODS: IN THE PRESENT STUDY, MALE AND FEMALE (> POSTNATAL DAY 60) SPRAGUE-DAWLEY RATS WERE ADMINISTERED ETOH (5.0 G/KG; INTRAGASTRIC GAVAGE) FOR 14 TO 15 CONSECUTIVE DAYS. TWENTY-FOUR HOURS AFTER THE FINAL ADMINISTRATION, ANIMALS WERE SACRIFICED AND BRAINS EXTRACTED FOR ELECTROPHYSIOLOGICAL RECORDINGS OF ISOLATED GABA(A) RECEPTOR-MEDIATED CURRENTS OR ANALYSIS OF GABA(A) RECEPTOR SUBUNIT PROTEIN EXPRESSION IN DEEP-LAYER PFC NEURONS. RESULTS: CHRONIC ETOH EXPOSURE SIGNIFICANTLY ATTENUATED ACTIVITY-DEPENDENT SPONTANEOUS GABA(A) RECEPTOR-MEDIATED INHIBITORY POSTSYNAPTIC CURRENT (IPSC) FREQUENCY WITH NO EFFECT ON AMPLITUDE. FURTHERMORE, ANALYSIS OF IPSC DECAY KINETICS REVEALED A SIGNIFICANT ENHANCEMENT OF IPSC DECAY TIME THAT WAS ASSOCIATED WITH DECREMENTS IN EXPRESSION OF THE ALPHA1 GABA(A) RECEPTOR SUBUNIT, INDICATIVE OF FURTHER IMPAIRED PHASIC INHIBITION. THESE PHENOMENA OCCURRED IRRESPECTIVE OF NEURON PROJECTION DESTINATION AND SEX. BASED ON PREVIOUS OBSERVATIONS BY OUR LABORATORY OF AN EPIGENETIC MECHANISM FOR ETOH-INDUCED CHANGES IN CORTICAL GABA(A) RECEPTOR SUBUNIT EXPRESSION, THE HISTONE DEACETYLASE INHIBITOR TRICHOSTATIN A WAS ADMINISTERED TO WATER- AND ETOH-EXPOSED ANIMALS, AND PREVENTED ETOH-INDUCED CHANGES IN SPONTANEOUS IPSC FREQUENCY, IPSC DECAY KINETICS, AND GABA(A) RECEPTOR SUBUNIT EXPRESSION. CONCLUSIONS: TAKEN TOGETHER, THESE RESULTS DEMONSTRATE THAT CHRONIC ETOH EXPOSURE IMPAIRS SYNAPTIC INHIBITORY NEUROTRANSMISSION IN DEEP-LAYER PYRAMIDAL NEURONS OF THE MEDIAL PFC IN BOTH MALE AND FEMALE RATS. THESE MALADAPTATIONS OCCUR IN NEURONS PROJECTING TO NUMEROUS REGIONS IMPLICATED IN THE SEQUELAE OF ETOH DEPENDENCE, OFFERING A MECHANISTIC LINK BETWEEN THE MANIFESTATION OF PFC DYSFUNCTION AND NEGATIVE AFFECTIVE STATES OBSERVED WITH EXTENDED CONSUMPTION. 2019 9 6108 37 THE ENRICHED ENVIRONMENT AMELIORATES CHRONIC UNPREDICTABLE MILD STRESS-INDUCED DEPRESSIVE-LIKE BEHAVIORS AND COGNITIVE IMPAIRMENT BY ACTIVATING THE SIRT1/MIR-134 SIGNALING PATHWAY IN HIPPOCAMPUS. BACKGROUND: CHRONIC UNPREDICTABLE MILD STRESS (CUMS) IS AN IMPORTANT RISK FACTOR FOR DEPRESSION AND COGNITIVE DEFICITS IN HUMANS. ENRICHED ENVIRONMENT (EE) SHOWED A BENEFICIAL EFFECT ON DEPRESSION AND COGNITION BY ENHANCING BRAIN DERIVED NEUROTROPHIC FACTOR (BDNF) EXPRESSION AND SYNAPTIC PLASTICITY. HOWEVER, IT IS STILL NOT CLEARLY UNDERSTOOD WHETHER AN EPIGENETIC MECHANISM IS INVOLVED IN THE BDNF MODULATION AND SYNAPTIC PLASTICITY THAT OCCURS AFTER EE TREATMENT FOR THE DEPRESSIVE-LIKE BEHAVIORS AND COGNITIVE DEFICITS ELICITED BY CUMS. IN THIS STUDY, WE INVESTIGATED THE POSSIBLE MECHANISM OF THE NEUROPROTECTIVE EFFECT OF EE. METHODS: ALL RATS WERE EXPOSED TO THE 5-WEEK CUMS PROCEDURE EXCEPT THE CONTROL GROUP. AFTER CUMS PROCEDURE, SOME RATS WERE STEREOTAXICALLY INJECTED WITH SIRT1 PHARMACOLOGIC INHIBITOR EX527 OR SIRT1 KNOCKING DOWN LENTIVIRUS (SH-SIRT1) IN THE HIPPOCAMPUS FOLLOWED BY EE TREATMENT FOR 3 WEEKS. OTHER RATS WERE DIRECTLY SUBJECTED TO EE TREATMENT WITHOUT STEREOTAXIC INJECTION. BEHAVIORAL TESTS WERE USED TO APPRAISE DEPRESSION AND COGNITION AFTER EE TREATMENT. THEN EPIGENETIC MOLECULES, SYNAPTIC PROTEINS, DENDRITIC SPINE DENSITY AND BRANCHES, AND SYNAPTIC MORPHOLOGY OF THE DORSAL HIPPOCAMPUS WERE DETERMINED. RESULTS: WE FOUND THAT CUMS INDUCED DEPRESSIVE-LIKE BEHAVIORS INCLUDING DECREASED SUCROSE PREFERENCE RATIO, PROLONGED IMMOBILITY AND REDUCED LOCOMOTOR AND EXPLORATORY ACTIVITY; COGNITIVE DEFICITS INCLUDING SPATIAL LEARNING AND MEMORY IMPAIRMENT; REDUCED DENDRITIC SPINE DENSITY AND NUMBER OF BRANCHES; THINNED POSTSYNAPTIC DENSITY; DOWNREGULATED SIRT1/MICRORNA-134 PATHWAY, DECREASED BDNF AND SYNAPTIC PROTEINS INCLUDING SYNAPTOPHYSIN (SYN) AND POSTSYNAPTIC DENSITY PROTEIN 95 (PSD95) EXPRESSION IN THE HIPPOCAMPUS. HOWEVER, THE CUMS-INDUCED DEPRESSIVE-LIKE BEHAVIORS, COGNITIVE DEFICITS, DENDRITIC SPINE DENSITY AND BRANCH NUMBER REDUCTION, POSTSYNAPTIC DENSITY THINNING, SIRT1/MICRORNA-134 PATHWAY DOWNREGULATION, BDNF AND SYNAPTIC PROTEINS REDUCTION, INCLUDING SYNAPTOPHYSIN (SYN) AND POSTSYNAPTIC DENSITY PROTEIN 95 (PSD95), WERE REVERSED BY EE TREATMENT. HOWEVER, DEPRESSIVE-LIKE BEHAVIORS AND COGNITIVE DEFICITS WERE OBSERVED AGAIN IN RATS SUBJECTED TO STEREOTAXIC INJECTION WITH EX527 OR SH-SIRT1. FURTHERMORE, THIS STUDY ALSO FOUND THAT SIRT1/MICRORNA-134 REGULATES THE DOWNSTREAM MOLECULES BDNF, AND THE SYNAPTIC PROTEINS SYN AND PSD95 IN PRIMARY CULTURED HIPPOCAMPAL NEURONS. CONCLUSIONS: THIS STUDY PROVIDES EVIDENCE FOR THE NEUROPROTECTIVE ROLE OF EE ON DEPRESSION AND COGNITIVE DEFICITS BY ACTIVATING THE SIRT1/MICRORNA-134 PATHWAY, WHICH ACCOUNTS FOR THE REGULATION OF SYNAPTIC PROTEINS, INCLUDING BDNF, PSD95 AND SYN, DENDRITIC REMODELING AND ULTRASTRUCTURE CHANGES OF SYNAPSES IN THE HIPPOCAMPUS. 2019 10 431 30 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 11 4930 36 PATERNAL ALCOHOL EXPOSURE REDUCES ACQUISITION OF OPERANT ALCOHOL SELF-ADMINISTRATION AND AFFECTS BDNF DNA METHYLATION IN MALE AND FEMALE OFFSPRING. FAMILIAL TRANSMISSION OF ALCOHOL USE DISORDER REFLECTS GENETIC AND ENVIRONMENTAL FACTORS. PATERNAL ALCOHOL EXPOSURE MAY AFFECT RODENT OFFSPRING VIA EPIGENETIC MODIFICATIONS TRANSMITTED THROUGH THE MALE GERM LINE. WHILE SUCH EXPOSURE ALTERS ALCOHOL SENSITIVITY IN MOUSE OFFSPRING, NO STUDIES EXAMINED IF IT IMPACTS THE DEVELOPMENT OF OPERANT ALCOHOL SELF-ADMINISTRATION IN RATS. WE EXPOSED MALE (SIRES) WISTAR RATS TO CHRONIC INTERMITTENT ETHANOL IN VAPOUR CHAMBERS (16 H/DAY; 5 DAYS/WEEK) OR TO AIR FOR 6 WEEKS. EIGHT WEEKS LATER, RATS WERE MATED WITH ALCOHOL-NAIVE FEMALES. ADULT ALCOHOL- AND CONTROL-SIRED F1 OFFSPRING WERE ASSESSED IN ACQUISITION OF ALCOHOL SELF-ADMINISTRATION IN WHICH INCREASING ALCOHOL CONCENTRATIONS (2.5%, 5% AND 10%, V/V) WERE DELIVERED AFTER ONE LEVER PRESS (FIXED RATIO 1 OR FR1). PRIOR TO ALCOHOL SESSIONS, RATS WERE TRAINED TO LEVER PRESS FOR FOOD DELIVERY UNDER AN FR1 SCHEDULE OF REINFORCEMENT. DNA METHYLATION LEVELS OF THE BRAIN DERIVED NEUROTROPHIC FACTOR (BDNF) GENE WERE MEASURED IN SPERM, NUCLEUS ACCUMBENS (NAC) AND MEDIAL PREFRONTAL CORTEX (MPFC) IN SIRES AND IN OFFSPRING. ALCOHOL-EXPOSED SIRES HAD LOWER BDNF DNA METHYLATION LEVELS IN NAC AND GREATER METHYLATION LEVELS IN MPFC. ALTHOUGH THIS PATTERN WAS NOT RECAPITULATED IN OFFSPRING, ALCOHOL-SIRED OFFSPRING OF BOTH SEXES DID SHOW ABERRANT BDNF DNA METHYLATION PATTERNS COMPARED TO CONTROL-SIRED OFFSPRING. ALCOHOL-SIRED OFFSPRING SELF-ADMINISTERED LESS ALCOHOL (5% AND 10%) WITH NO GROUP DIFFERENCES IN FOOD RESPONDING. RESULTS INDICATE THAT PATERNAL ALCOHOL EXPOSURE PRIOR TO CONCEPTION PROTECTS AGAINST ALCOHOL'S INITIAL REINFORCING EFFECTS BUT THE PATTERN OF DYSREGULATED BDNF METHYLATION IN REWARD-RELATED CIRCUITRY DID NOT MIMIC CHANGES SEEN IN SIRES. 2022 12 6388 35 THE ROLE OF SIRT1 IN THE BASOLATERAL AMYGDALA IN DEPRESSION-LIKE BEHAVIORS IN MICE. PREVIOUS INVESTIGATIONS HAVE IMPLICATED THE BASOLATERAL AMYGDALA (BLA) EPIGENETIC MECHANISMS IN THE PATHOPHYSIOLOGY OF DEPRESSION. SIRT1 IS A NAD+-DEPENDENT CLASS III HISTONE DEACETYLASE, WIDELY EXPRESSES IN BLA. HOWEVER, EPIGENETIC MECHANISMS IN THE BLA UNDER THE REGULATION OF SIRT1 IN THE DEPRESSION ARE LARGELY UNCHARACTERIZED. UNDER THE CHRONIC UNPREDICTABLE CHRONIC MILD STRESS (CUMS) MOUSE MODEL, WE USED ADENO-ASSOCIATED VIRAL VECTORS (AAV) THAT ENCODED SIRT1-SHRNA OR SIRT1 TO SPECIFICALLY KNOCKDOWN OR OVEREXPRESS SIRT1 IN BLA NEURONS, RESPECTIVELY. CUMS PROCEDURE INDUCED SIGNIFICANT DEPRESSION SYMPTOMS INCLUDING THE DECREASED SUCROSE PREFERENCE, THE LESS BODYWEIGHT GAINED, THE DECREASED IMMOBILE LATENCY AND THE INCREASED IMMOBILE TIME BOTH IN FORCED SWIM TEST (FST) AND TAIL SUSPENSION TEST (TST). KNOCKDOWN OF SIRT1 IN BLA GLUTAMATERGIC NEURONS REVERSED THESE DEPRESSION-LIKE BEHAVIORS AND RESTORED THE SYNAPTIC ABNORMALITIES. OVEREXPRESSION OF SIRT1 IN BLA GLUTAMATERGIC NEURONS INDUCED DEPRESSION-LIKE BEHAVIORS IN NON-STRESSED CONTROL MICE. THE RESULT OF PROTEIN EXPRESSIONS AND ULTRASTRUCTURAL CHANGES WERE CONSISTENT WITH THE BEHAVIORAL RESULTS. OUR STUDY SUGGESTED THAT DOWNREGULATION OF SIRT1 IN BLA HAS CERTAIN BENEFICIAL EFFECT ON CUMS-INDUCED DEPRESSION-LIKE BEHAVIORS SUCH AS ANOREXIA, ANHEDONIA, HOPELESSNESS AND DESPAIR. IN ADDITION, THE INCREASED EXPRESSION OF SIRT1 MAY BE THE IMMEDIATE CAUSE OF DEPRESSIVE-LIKE SYMPTOMS. THE ABNORMAL EXPRESSION OF SIRT1 MAY AFFECT THE TRANSCRIPTIONAL REGULATION MECHANISM AND SIGNALING PROTEIN ACETYLATION, AFFECTING NEUROPLASTICITY AND ULTIMATELY CONTRIBUTE TO MDD. IN THE STRESS-SUSCEPTIBLE MICE, THESE TWO MECHANISMS MAY CO-EXIST, BUT THE SPECIFIC MECHANISM NEEDS FURTHER RESEARCH. 2021 13 3331 34 HISTONE DEACETYLASE INHIBITOR SUBERANILOHYDROXAMIC ACID TREATMENT REVERSES HYPOSENSITIVITY TO GAMMA-AMINOBUTYRIC ACID IN THE VENTRAL TEGMENTAL AREA DURING ETHANOL WITHDRAWAL. BACKGROUND: THE VENTRAL TEGMENTAL AREA (VTA) IS IMPORTANT FOR ALCOHOL-RELATED REWARD AND REINFORCEMENT. MOUSE VTA NEURONS ARE HYPOSENSITIVE TO GAMMA-AMINOBUTYRIC ACID (GABA) DURING ETHANOL (ETOH) WITHDRAWAL, AND GABA RESPONSIVENESS IS NORMALIZED BY IN VITRO TREATMENT WITH HISTONE DEACETYLASE INHIBITORS (HDACI). THE PRESENT STUDY EXAMINED THE EFFECT OF A SYSTEMICALLY ADMINISTERED HDACI, SUBERANILOHYDROXAMIC ACID (SAHA) ON GABA SENSITIVITY, AND RELATED MOLECULAR CHANGES IN VTA NEURONS DURING WITHDRAWAL AFTER CHRONIC ETOH INTAKE IN RATS. METHODS: SPRAGUE DAWLEY MALE ADULT RATS WERE FED WITH LIEBER-DECARLI DIET (9% ETOH OR CONTROL DIET) FOR 16 DAYS. EXPERIMENTAL GROUPS INCLUDED CONTROL DIET-FED AND ETOH DIET-FED (0- OR 24-HOUR WITHDRAWAL) RATS TREATED WITH EITHER SAHA OR VEHICLE INJECTION. SINGLE-UNIT RECORDINGS WERE USED TO MEASURE THE RESPONSE OF VTA NEURONS TO GABA. IMMUNOHISTOCHEMISTRY WAS PERFORMED TO EXAMINE LEVELS OF HDAC2, ACETYLATED HISTONE H3 LYSINE 9 (ACH3K9), AND GABA(A) RECEPTOR ALPHA1 AND ALPHA5 SUBUNITS IN THE VTA; QUANTITATIVE POLYMERASE CHAIN REACTION WAS PERFORMED TO EXAMINE THE MRNA LEVELS OF HDAC2 AND GABA(A) RECEPTOR SUBUNITS. RESULTS: VTA NEURONS FROM THE WITHDRAWAL GROUP EXHIBITED GABA HYPOSENSITIVITY. IN VIVO SAHA TREATMENT 2 HOURS BEFORE SACRIFICE NORMALIZED THE SENSITIVITY OF VTA NEURONS TO GABA. ETOH WITHDRAWAL WAS ASSOCIATED WITH INCREASED HDAC2 AND DECREASED ACH3K9 PROTEIN LEVELS; SAHA TREATMENT NORMALIZED ACH3K9 LEVELS. INTERESTINGLY, NO SIGNIFICANT CHANGE WAS OBSERVED IN THE MRNA LEVELS OF HDAC2. THE MRNA LEVELS, BUT NOT PROTEIN LEVELS, OF GABA(A) RECEPTOR ALPHA1 AND ALPHA5 SUBUNITS WERE INCREASED DURING WITHDRAWAL. CONCLUSIONS: WITHDRAWAL FROM CHRONIC ETOH EXPOSURE RESULTS IN A DECREASE IN GABA-MEDIATED INHIBITION, AND THIS GABA HYPOSENSITIVITY IS NORMALIZED BY IN VIVO SAHA TREATMENT. DISRUPTION OF SIGNALING IN THE VTA PRODUCED BY ALTERATION OF GABA NEUROTRANSMISSION COULD BE 1 NEUROADAPTIVE PHYSIOLOGICAL PROCESS LEADING TO CRAVING AND RELAPSE. THESE RESULTS SUGGEST THAT HDACI PHARMACOTHERAPY WITH AGENTS LIKE SAHA MIGHT BE AN EFFECTIVE TREATMENT FOR ALCOHOLISM. 2018 14 4212 28 METHAMPHETAMINE DOWNREGULATES STRIATAL GLUTAMATE RECEPTORS VIA DIVERSE EPIGENETIC MECHANISMS. BACKGROUND: CHRONIC METHAMPHETAMINE (METH) EXPOSURE CAUSES NEUROADAPTATIONS AT GLUTAMATERGIC SYNAPSES. METHODS: TO IDENTIFY THE METH-INDUCED EPIGENETIC UNDERPINNINGS OF THESE NEUROADAPTATIONS, WE INJECTED INCREASING METH DOSES TO RATS FOR 2 WEEKS AND MEASURED STRIATAL GLUTAMATE RECEPTOR EXPRESSION. WE THEN QUANTIFIED THE EFFECTS OF METH EXPOSURE ON HISTONE ACETYLATION. WE ALSO MEASURED METH-INDUCED CHANGES IN DNA METHYLATION AND DNA HYDROXYMETHYLATION. RESULTS: CHRONIC METH DECREASED TRANSCRIPT AND PROTEIN EXPRESSION OF GLUA1 AND GLUA2 ALPHA-AMINO-3-HYDROXY-5-METHYL-4-ISOXAZOLE PROPIONIC ACID RECEPTOR (AMPAR) AND GLUN1 N-METHYL-D-ASPARTATE RECEPTOR SUBUNITS. THESE CHANGES WERE ASSOCIATED WITH ALTERED ELECTROPHYSIOLOGICAL GLUTAMATERGIC RESPONSES IN STRIATAL NEURONS. CHROMATIN IMMUNOPRECIPITATION-POLYMERASE CHAIN REACTION REVEALED THAT METH DECREASED ENRICHMENT OF ACETYLATED HISTONE H4 ON GLUA1, GLUA2, AND GLUN1 PROMOTERS. METHAMPHETAMINE EXPOSURE ALSO INCREASED REPRESSOR ELEMENT-1 SILENCING TRANSCRIPTION FACTOR (REST) COREPRESSOR 1, METHYLATED CPG BINDING PROTEIN 2, AND HISTONE DEACETYLASE 2 ENRICHMENT, BUT NOT OF SIRTUIN 1 OR SIRTUIN 2, ONTO GLUA1 AND GLUA2 GENE SEQUENCES. MOREOVER, METH CAUSED INTERACTIONS OF REST COREPRESSOR 1 AND METHYLATED CPG BINDING PROTEIN 2 WITH HISTONE DEACETYLASE 2 AND OF REST WITH HISTONE DEACETYLASE 1. SURPRISINGLY, METHYLATED DNA IMMUNOPRECIPITATION AND HYDROXYMETHYLATED DNA IMMUNOPRECIPITATION-POLYMERASE CHAIN REACTION REVEALED METH-INDUCED DECREASED ENRICHMENT OF 5-METHYLCYTOSINE AND 5-HYDROXYMETHYLCYTOSINE AT GLUA1 AND GLUA2 PROMOTER SEQUENCES. IMPORTANTLY, THE HISTONE DEACETYLASE INHIBITOR, VALPROIC ACID, BLOCKED METH-INDUCED DECREASED EXPRESSION OF AMPAR AND N-METHYL-D-ASPARTATE RECEPTOR SUBUNITS. FINALLY, VALPROIC ACID ALSO ATTENUATED METH-INDUCED DECREASE H4K16AC RECRUITMENT ON AMPAR GENE SEQUENCES. CONCLUSIONS: THESE OBSERVATIONS SUGGEST THAT HISTONE H4 HYPOACETYLATION MAY BE THE MAIN DETERMINANT OF METH-INDUCED DECREASED STRIATAL GLUTAMATE RECEPTOR EXPRESSION. 2014 15 2826 44 FLUOXETINE EPIGENETICALLY ALTERS THE CAMKIIALPHA PROMOTER IN NUCLEUS ACCUMBENS TO REGULATE DELTAFOSB BINDING AND ANTIDEPRESSANT EFFECTS. CHRONIC SOCIAL DEFEAT STRESS IN MICE PRODUCES A SUSCEPTIBLE PHENOTYPE CHARACTERIZED BY SEVERAL BEHAVIORAL ABNORMALITIES CONSISTENT WITH HUMAN DEPRESSION THAT ARE REVERSED BY CHRONIC BUT NOT ACUTE EXPOSURE TO ANTIDEPRESSANT MEDICATIONS. RECENT WORK IN ADDICTION MODELS DEMONSTRATES THAT THE TRANSCRIPTION FACTOR DELTAFOSB AND PROTEIN KINASE CALMODULIN-DEPENDENT PROTEIN KINASE II (CAMKII) ARE CO-REGULATED IN NUCLEUS ACCUMBENS (NAC), A BRAIN REWARD REGION IMPLICATED IN BOTH ADDICTION AND DEPRESSION MODELS INCLUDING SOCIAL DEFEAT. PREVIOUS WORK HAS ALSO DEMONSTRATED THAT DELTAFOSB IS INDUCED IN NAC AFTER CHRONIC SOCIAL DEFEAT STRESS OR AFTER CHRONIC ANTIDEPRESSANT TREATMENT, WHEREIN IT MEDIATES A PRO-RESILIENCE OR ANTIDEPRESSANT-LIKE PHENOTYPE. HERE, USING CHROMATIN IMMUNOPRECIPITATION ASSAYS, WE FOUND THAT DELTAFOSB BINDS THE CAMKIIALPHA GENE PROMOTER IN NAC AND THAT THIS BINDING INCREASES AFTER MICE ARE EXPOSED TO CHRONIC SOCIAL DEFEAT STRESS. PARADOXICALLY, CHRONIC EXPOSURE TO THE ANTIDEPRESSANT FLUOXETINE REDUCES BINDING OF DELTAFOSB TO THE CAMKIIALPHA PROMOTER AND REDUCES CAMKII EXPRESSION IN NAC, DESPITE THE FACT THAT DELTAFOSB IS INDUCED UNDER THESE CONDITIONS. THESE DATA SUGGEST A NOVEL EPIGENETIC MECHANISM OF ANTIDEPRESSANT ACTION, WHEREBY FLUOXETINE INDUCES SOME CHROMATIN CHANGE AT THE CAMKIIALPHA PROMOTER, WHICH BLOCKS THE DELTAFOSB BINDING. INDEED, CHRONIC FLUOXETINE REDUCES ACETYLATION AND INCREASES LYSINE-9 DIMETHYLATION OF HISTONE H3 AT THE CAMKIIALPHA PROMOTER IN NAC, EFFECTS ALSO SEEN IN DEPRESSED HUMANS EXPOSED TO ANTIDEPRESSANTS. OVEREXPRESSION OF CAMKII IN NAC BLOCKS FLUOXETINE'S ANTIDEPRESSANT EFFECTS IN THE CHRONIC SOCIAL DEFEAT PARADIGM, WHEREAS INHIBITION OF CAMKII ACTIVITY IN NAC MIMICS FLUOXETINE EXPOSURE. THESE FINDINGS SUGGEST THAT EPIGENETIC SUPPRESSION OF CAMKIIALPHA EXPRESSION IN NAC IS BEHAVIORALLY RELEVANT AND OFFER A NOVEL PATHWAY FOR POSSIBLE THERAPEUTIC INTERVENTION IN DEPRESSION AND RELATED SYNDROMES. 2014 16 5021 39 PERSISTENT PAIN MAINTAINS MORPHINE-SEEKING BEHAVIOR AFTER MORPHINE WITHDRAWAL THROUGH REDUCED MECP2 REPRESSION OF GLUA1 IN RAT CENTRAL AMYGDALA. AS LONG-TERM OPIOIDS ARE INCREASINGLY USED FOR CONTROL OF CHRONIC PAIN, HOW PAIN AFFECTS THE REWARDING EFFECT OF OPIOIDS AND HENCE RISK OF PRESCRIPTION OPIOID MISUSE AND ABUSE REMAINS A HEALTHCARE CONCERN AND A CHALLENGING ISSUE IN CURRENT PAIN MANAGEMENT. IN THIS STUDY, USING A RAT MODEL OF MORPHINE SELF-ADMINISTRATION, WE INVESTIGATED THE MOLECULAR MECHANISMS UNDERLYING THE IMPACT OF PAIN ON OPERANT BEHAVIOR OF MORPHINE INTAKE AND MORPHINE SEEKING BEFORE AND AFTER MORPHINE WITHDRAWAL. WE FOUND THAT RATS WITH PERSISTENT PAIN CONSUMED A SIMILAR AMOUNT OF DAILY MORPHINE TO THAT IN CONTROL RATS WITHOUT PAIN, BUT MAINTAINED THEIR LEVEL-PRESSING BEHAVIOR OF MORPHINE SEEKING AFTER ABSTINENCE OF MORPHINE AT 0.2 MG/KG, WHEREAS THIS BEHAVIOR WAS GRADUALLY DIMINISHED IN CONTROL RATS. IN THE CENTRAL NUCLEUS OF AMYGDALA (CEA), A LIMBIC STRUCTURE CRITICALLY INVOLVED IN THE AFFECTIVE DIMENSION OF PAIN, PROTEINS OF GLUA1 SUBUNITS OF GLUTAMATE AMPA RECEPTORS WERE UPREGULATED DURING MORPHINE WITHDRAWAL, AND VIRAL KNOCKDOWN OF CEA GLUA1 ELIMINATED THE MORPHINE-SEEKING BEHAVIOR IN WITHDRAWN RATS OF THE PAIN GROUP. CHROMATIN IMMUNOPRECIPITATION ANALYSIS REVEALED THAT THE METHYL CPG-BINDING PROTEIN 2 (MECP2) WAS ENRICHED IN THE PROMOTER REGION OF GRIA1 ENCODING GLUA1 AND THIS ENRICHMENT WAS SIGNIFICANTLY ATTENUATED IN WITHDRAWN RATS OF THE PAIN GROUP. FURTHERMORE, VIRAL OVEREXPRESSION OF CEA MECP2 REPRESSED THE GLUA1 LEVEL AND ELIMINATED THE MAINTENANCE OF MORPHINE-SEEKING BEHAVIOR AFTER MORPHINE WITHDRAWAL. THESE RESULTS SUGGEST DIRECT MECP2 REPRESSION OF GLUA1 FUNCTION AS A LIKELY MECHANISM FOR MORPHINE-SEEKING BEHAVIOR MAINTAINED BY LONG-LASTING AFFECTIVE PAIN AFTER MORPHINE WITHDRAWAL. 2015 17 3314 37 HIPPOCAMPAL CANNABINOID 1 RECEPTORS ARE MODULATED FOLLOWING COCAINE SELF-ADMINISTRATION IN MALE RATS. COCAINE ADDICTION IS A COMPLEX PATHOLOGY INDUCING LONG-TERM NEUROPLASTIC CHANGES THAT, IN TURN, CONTRIBUTE TO MALADAPTIVE BEHAVIORS. THIS BEHAVIORAL DYSREGULATION IS ASSOCIATED WITH TRANSCRIPTIONAL REPROGRAMMING IN BRAIN REWARD CIRCUITRY, ALTHOUGH THE MECHANISMS UNDERLYING THIS MODULATION REMAIN POORLY UNDERSTOOD. THE ENDOGENOUS CANNABINOID SYSTEM MAY PLAY A ROLE IN THIS PROCESS IN THAT CANNABINOID MECHANISMS MODULATE DRUG REWARD AND CONTRIBUTE TO COCAINE-INDUCED NEURAL ADAPTATIONS. IN THIS STUDY, WE INVESTIGATED WHETHER COCAINE SELF-ADMINISTRATION INDUCES LONG-TERM ADAPTATIONS, INCLUDING TRANSCRIPTIONAL MODIFICATIONS AND ASSOCIATED EPIGENETIC PROCESSES. WE FIRST EXAMINED ENDOCANNABINOID GENE EXPRESSION IN REWARD-RELATED BRAIN REGIONS OF THE RAT FOLLOWING SELF-ADMINISTERED (0.33 MG/KG INTRAVENOUS, FR1, 10 DAYS) COCAINE INJECTIONS. INTERESTINGLY, WE FOUND INCREASED CNR1 EXPRESSION IN SEVERAL STRUCTURES, INCLUDING PREFRONTAL CORTEX, NUCLEUS ACCUMBENS, DORSAL STRIATUM, HIPPOCAMPUS, HABENULA, AMYGDALA, LATERAL HYPOTHALAMUS, VENTRAL TEGMENTAL AREA, AND ROSTROMEDIAL TEGMENTAL NUCLEUS, WITH MOST PRONOUNCED EFFECTS IN THE HIPPOCAMPUS. ENDOCANNABINOID LEVELS, MEASURED BY MASS SPECTROMETRY, WERE ALSO ALTERED IN THIS STRUCTURE. CHROMATIN IMMUNOPRECIPITATION FOLLOWED BY QPCR IN THE HIPPOCAMPUS REVEALED THAT TWO ACTIVATING HISTONE MARKS, H3K4ME3 AND H3K27AC, WERE ENRICHED AT SPECIFIC ENDOCANNABINOID GENES FOLLOWING COCAINE INTAKE. TARGETING CB1 RECEPTORS USING CHROMOSOME CONFORMATION CAPTURE, WE HIGHLIGHTED SPATIAL CHROMATIN RE-ORGANIZATION IN THE HIPPOCAMPUS, AS WELL AS IN THE NUCLEUS ACCUMBENS, SUGGESTING THAT DESTABILIZATION OF THE CHROMATIN MAY CONTRIBUTE TO NEURONAL RESPONSES TO COCAINE. OVERALL, OUR RESULTS HIGHLIGHT A KEY ROLE FOR THE HIPPOCAMPUS IN COCAINE-INDUCED PLASTICITY AND BROADEN THE UNDERSTANDING OF NEURONAL ALTERATIONS ASSOCIATED WITH ENDOCANNABINOID SIGNALING. THE LATTER SUGGESTS THAT EPIGENETIC MODIFICATIONS CONTRIBUTE TO MALADAPTIVE BEHAVIORS ASSOCIATED WITH CHRONIC DRUG USE. 2022 18 5651 28 SEX DIFFERENCES IN THE EPIGENETIC REGULATION OF CHRONIC VISCERAL PAIN FOLLOWING UNPREDICTABLE EARLY LIFE STRESS. BACKGROUND: WE PREVIOUSLY REPORTED THAT EARLY LIFE STRESS (ELS) DYSREGULATED GLUCOCORTICOID RECEPTOR (GR) AND CORTICOTROPHIN-RELEASING HORMONE (CRH) EXPRESSION IN THE CENTRAL NUCLEUS OF THE AMYGDALA (CEA). EPIGENETIC MODIFICATIONS SERVE AS MEMORIES OF ADVERSE EVENTS THAT OCCURRED DURING EARLY LIFE. THEREFORE, WE HYPOTHESIZED THAT EPIGENETIC MECHANISMS ALTER GR AND CRH EXPRESSION IN THE CEA AND UNDERLIE CHRONIC VISCERAL PAIN AFTER ELS. METHODS: NEONATAL RATS WERE EXPOSED TO UNPREDICTABLE, PREDICTABLE ELS, OR ODOR ONLY (NO STRESS CONTROL) FROM POSTNATAL DAYS 8 TO 12. IN ADULTHOOD, VISCERAL SENSITIVITY WAS ASSESSED OR THE CEA WAS ISOLATED FOR WESTERN BLOT OR CHIP-QPCR TO STUDY HISTONE MODIFICATIONS AT THE GR AND CRH PROMOTERS. FEMALE ADULT RATS UNDERWENT STEREOTAXIC IMPLANTATION OF INDWELLING CANNULAS FOR MICROINJECTIONS OF GARCINOL (HAT INHIBITOR) INTO THE CEA. AFTER 7 DAYS OF MICROINJECTIONS, VISCERAL SENSITIVITY WAS ASSESSED OR THE CEA WAS ISOLATED FOR CHIP-QPCR ASSAYS. RESULTS: UNPREDICTABLE ELS INCREASED VISCERAL SENSITIVITY IN ADULT FEMALE RATS, BUT NOT IN MALE COUNTERPARTS. ELS INCREASED HISTONE 3 LYSINE 9 (H3K9) ACETYLATION IN THE CEA AND H3K9 ACETYLATION LEVELS AT THE GR PROMOTER IN THE CEA OF ADULT FEMALE RATS. AFTER UNPREDICTABLE ELS, H3K9 ACETYLATION WAS INCREASED AND GR BINDING WAS DECREASED AT THE CRH PROMOTER. ADMINISTRATION OF GARCINOL IN THE CEA OF ADULT FEMALES, THAT UNDERWENT UNPREDICTABLE ELS, NORMALIZED H3K9 ACETYLATION AND RESTORED GR BINDING AT THE CRH PROMOTER. CONCLUSION: DYSREGULATED HISTONE ACETYLATION AND GR BINDING AT THE CRH PROMOTER IN THE CEA ARE AN IMPORTANT MECHANISM FOR "MEMORIZING" ELS EVENTS MEDIATING VISCERAL PAIN IN ADULTHOOD. 2020 19 4878 42 OVEREXPRESSION OF THE HISTONE DIMETHYLTRANSFERASE G9A IN NUCLEUS ACCUMBENS SHELL INCREASES COCAINE SELF-ADMINISTRATION, STRESS-INDUCED REINSTATEMENT, AND ANXIETY. REPEATED EXPOSURE TO COCAINE INDUCES LASTING EPIGENETIC CHANGES IN NEURONS THAT PROMOTE THE DEVELOPMENT AND PERSISTENCE OF ADDICTION. ONE EPIGENETIC ALTERATION INVOLVES REDUCTIONS IN LEVELS OF THE HISTONE DIMETHYLTRANSFERASE G9A IN NUCLEUS ACCUMBENS (NAC) AFTER CHRONIC COCAINE ADMINISTRATION. THIS REDUCTION IN G9A MAY ENHANCE COCAINE REWARD BECAUSE OVEREXPRESSING G9A IN THE NAC DECREASES COCAINE-CONDITIONED PLACE PREFERENCE. THEREFORE, WE HYPOTHESIZED THAT HSV-MEDIATED G9A OVEREXPRESSION IN THE NAC SHELL (NACSH) WOULD ATTENUATE COCAINE SELF-ADMINISTRATION (SA) AND COCAINE-SEEKING BEHAVIOR. INSTEAD, WE FOUND THAT G9A OVEREXPRESSION, AND THE RESULTING INCREASE IN HISTONE 3 LYSINE 9 DIMETHYLATION (H3K9ME2), INCREASES SENSITIVITY TO COCAINE REINFORCEMENT AND ENHANCES MOTIVATION FOR COCAINE IN SELF-ADMINISTERING MALE RATS. MOREOVER, WHEN G9A OVEREXPRESSION IS LIMITED TO THE INITIAL 15 D OF COCAINE SA TRAINING, IT PRODUCES AN ENDURING POSTEXPRESSION ENHANCEMENT IN COCAINE SA AND PROLONGED (OVER 5 WEEKS) INCREASES IN REINSTATEMENT OF COCAINE SEEKING INDUCED BY FOOT-SHOCK STRESS, BUT IN THE ABSENCE OF CONTINUED GLOBAL ELEVATIONS IN H3K9ME2. THE INCREASE IN STRESS-INDUCED REINSTATEMENT IS PARALLELED BY HEIGHTENED ANXIETY MEASURES, SUGGESTING THAT COUNTERING THE COCAINE-INDUCED DECREASES IN ENDOGENOUS G9A WITH ECTOPIC G9A OVEREXPRESSION LEADS TO LASTING ANXIOGENIC EFFECTS. FINALLY, WE FOUND AN ENDURING REDUCTION IN PHOSPHORYLATED CAMP-RESPONSE ELEMENT BINDING PROTEIN LEVELS IN THE NACSH THAT COULD ACCOUNT FOR THE INCREASED ANXIETY. THESE DATA DEMONSTRATE A NOVEL ROLE FOR G9A IN PROMOTING COMORBID COCAINE ADDICTION AND ANXIETY AND SUGGEST THAT INCREASED EPIGENETIC REPRESSION OF TRANSCRIPTION THROUGH H3K9 DURING COCAINE USE CAN HAVE LONG-LASTING AND UNEXPECTED NEGATIVE CONSEQUENCES ON BEHAVIOR.SIGNIFICANCE STATEMENT COCAINE ADDICTION IS A NEUROPSYCHIATRIC DISORDER THAT IS DETRIMENTAL TO SOCIETY AND CURRENTLY HAS NO EFFECTIVE TREATMENTS. THE DIFFICULTY IN TREATING DRUG ADDICTION IS COMPOUNDED BY THE HIGH COMORBIDITY WITH OTHER PSYCHIATRIC ILLNESSES, INCLUDING ANXIETY DISORDERS. HERE, WE DEMONSTRATE THAT G9A, AN EPIGENETIC REPRESSOR OF GENE EXPRESSION, ACTING IN THE NUCLEUS ACCUMBENS, A BRAIN REWARD REGION, IS CAPABLE OF INCREASING BOTH ADDICTION- AND ANXIETY-LIKE BEHAVIORS IN RATS. THESE FINDINGS ARE INTRIGUING BECAUSE REPEATED COCAINE EXPOSURE DECREASES G9A IN THIS REGION AND THEREBY ENHANCES EXPRESSION OF CERTAIN ADDICTION-PROMOTING GENES. HOWEVER, OUR RESULTS SUGGEST THAT COUNTERING THIS COCAINE-INDUCED DECREASE IN G9A ACTIVITY ACTUALLY EXACERBATES ADDICTION AND SENSITIVITY TO RELAPSE UNDER STRESSFUL SITUATIONS. 2018 20 3315 29 HIPPOCAMPAL MU OPIOID RECEPTORS ARE MODULATED FOLLOWING COCAINE SELF-ADMINISTRATION IN RAT. COCAINE ADDICTION IS A COMPLEX PATHOLOGY INDUCED BY LONG-TERM BRAIN CHANGES. UNDERSTANDING THE NEUROCHEMICAL CHANGES UNDERLYING THE REINFORCING EFFECTS OF THIS DRUG OF ABUSE IS CRITICAL FOR REDUCING THE SOCIETAL BURDEN OF DRUG ADDICTION. THE MU OPIOID RECEPTOR PLAYS A MAJOR ROLE IN DRUG REWARD. THIS RECEPTOR IS MODULATED BY CHRONIC COCAINE TREATMENT IN SPECIFIC BRAIN STRUCTURES, BUT FEW STUDIES INVESTIGATED NEUROCHEMICAL ADAPTATIONS INDUCED BY VOLUNTARY COCAINE INTAKE. IN THIS STUDY, WE INVESTIGATED WHETHER INTRAVENOUS COCAINE-SELF ADMINISTRATION (0.33 MG/KG/INJECTION, FIXED-RATIO 1 [FR1], 10 DAYS) IN RATS INDUCES TRANSCRIPTIONAL AND FUNCTIONAL CHANGES OF THE MU OPIOID RECEPTOR IN REWARD-RELATED BRAIN REGIONS. EPIGENETIC PROCESSES WITH HISTONE MODIFICATIONS WERE EXAMINED FOR TWO ACTIVATING MARKS, H3K4ME3, AND H3K27AC. WE FOUND AN INCREASE OF MU OPIOID RECEPTOR GENE EXPRESSION ALONG WITH A POTENTIATION OF ITS FUNCTIONALITY IN HIPPOCAMPUS OF COCAINE SELF-ADMINISTERING ANIMALS COMPARED TO SALINE CONTROLS. CHROMATIN IMMUNOPRECIPITATION FOLLOWED BY QPCR REVEALED NO MODIFICATIONS OF THE HISTONE MARK H3K4ME3 AND H3K27AC LEVELS AT MU OPIOID RECEPTOR PROMOTER. OUR STUDY HIGHLIGHTS THE HIPPOCAMPUS AS AN IMPORTANT TARGET TO FURTHER INVESTIGATE NEUROADAPTIVE PROCESSES LEADING TO COCAINE ADDICTION. 2021