1 1086 154 COCAINE ADMINISTRATION AND ITS WITHDRAWAL ENHANCE THE EXPRESSION OF GENES ENCODING HISTONE-MODIFYING ENZYMES AND HISTONE ACETYLATION IN THE RAT PREFRONTAL CORTEX. CHRONIC EXPOSURE TO COCAINE, CRAVING, AND RELAPSE ARE ATTRIBUTED TO LONG-LASTING CHANGES IN GENE EXPRESSION ARISING THROUGH EPIGENETIC AND TRANSCRIPTIONAL MECHANISMS. ALTHOUGH SEVERAL BRAIN REGIONS ARE INVOLVED IN THESE PROCESSES, THE PREFRONTAL CORTEX SEEMS TO PLAY A CRUCIAL ROLE NOT ONLY IN MOTIVATION AND DECISION-MAKING BUT ALSO IN EXTINCTION AND SEEKING BEHAVIOR. IN THIS STUDY, WE APPLIED COCAINE SELF-ADMINISTRATION AND EXTINCTION TRAINING PROCEDURES IN RATS WITH A YOKED TRIAD TO DETERMINE DIFFERENTIALLY EXPRESSED GENES IN PREFRONTAL CORTEX. MICROARRAY ANALYSIS SHOWED SIGNIFICANT UPREGULATION OF SEVERAL GENES ENCODING HISTONE MODIFICATION ENZYMES DURING EARLY EXTINCTION TRAINING. SUBSEQUENT REAL-TIME PCR TESTING OF THESE GENES FOLLOWING COCAINE SELF-ADMINISTRATION OR EARLY (THIRD DAY) AND LATE (TENTH DAY) EXTINCTION REVEALED ELEVATED LEVELS OF THEIR TRANSCRIPTS. INTERESTINGLY, WE FOUND THE ENRICHMENT OF BRD1 MESSENGER RNA IN RATS SELF-ADMINISTERING COCAINE THAT LASTED UNTIL EXTINCTION TRAINING DURING COCAINE WITHDRAWAL WITH CONCOMITANT INCREASED ACETYLATION OF H3K9 AND H4K8. HOWEVER, DESPITE ELEVATED LEVELS OF METHYL- AND DEMETHYLTRANSFERASE-ENCODED TRANSCRIPTS, NO CHANGES IN GLOBAL DI- AND TRI-METHYLATION OF HISTONE H3 AT LYSINE 4, 9, 27, AND 79 WERE OBSERVED. SURPRISINGLY, AT THE END OF EXTINCTION TRAINING (10 DAYS OF COCAINE WITHDRAWAL), MOST OF THE ANALYZED GENES IN THE RATS ACTIVELY AND PASSIVELY ADMINISTERING COCAINE RETURNED TO THE CONTROL LEVEL. TOGETHER, THE ALTERATIONS IDENTIFIED IN THE RAT PREFRONTAL CORTEX MAY SUGGEST ENHANCED CHROMATIN REMODELING AND TRANSCRIPTIONAL ACTIVITY INDUCED BY EARLY COCAINE ABSTINENCE; HOWEVER, TO KNOW WHETHER THEY ARE BENEFICIAL OR NOT FOR THE EXTINCTION OF DRUG-SEEKING BEHAVIOR, FURTHER IN VIVO EVALUATION IS REQUIRED. 2017 2 5485 46 REVERSAL OF COCAINE-CONDITIONED PLACE PREFERENCE THROUGH METHYL SUPPLEMENTATION IN MICE: ALTERING GLOBAL DNA METHYLATION IN THE PREFRONTAL CORTEX. ANALYSIS OF GLOBAL METHYLATION IN CELLS HAS REVEALED CORRELATIONS BETWEEN OVERALL DNA METHYLATION STATUS AND SOME BIOLOGICAL STATES. RECENT STUDIES SUGGEST THAT EPIGENETIC REGULATION THROUGH DNA METHYLATION COULD BE RESPONSIBLE FOR NEUROADAPTATIONS INDUCED BY ADDICTIVE DRUGS. HOWEVER, THERE IS NO INVESTIGATION TO DETERMINE GLOBAL DNA METHYLATION STATUS FOLLOWING REPEATED EXPOSURE TO ADDICTIVE DRUGS. USING MICE CONDITIONED PLACE PREFERENCE (CPP) PROCEDURE, WE MEASURED GLOBAL DNA METHYLATION LEVEL IN THE NUCLEUS ACCUMBENS (NAC) AND THE PREFRONTAL CORTEX (PFC) ASSOCIATED WITH DRUG REWARDING EFFECTS. WE FOUND THAT COCAINE-, BUT NOT MORPHINE- OR FOOD-CPP TRAINING DECREASED GLOBAL DNA METHYLATION IN THE PFC. CHRONIC TREATMENT WITH METHIONINE, A METHYL DONOR, FOR 25 CONSECUTIVE DAYS PRIOR TO AND DURING CPP TRAINING INHIBITED THE ESTABLISHMENT OF COCAINE, BUT NOT MORPHINE OR FOOD CPP. WE ALSO FOUND THAT BOTH MRNA AND PROTEIN LEVEL OF DNMT (DNA METHYTRANSFERASE) 3B IN THE PFC WERE DOWNREGULATED FOLLOWING THE ESTABLISHMENT OF COCAINE CPP, AND THE DOWNREGULATION COULD BE REVERSED BY REPEATED ADMINISTRATION OF METHIONINE. OUR STUDY INDICATES A CRUCIAL ROLE OF GLOBAL PFC DNA HYPOMETHYLATION IN THE REWARDING EFFECTS OF COCAINE. REVERSAL OF GLOBAL DNA HYPOMETHYLATION COULD SIGNIFICANTLY ATTENUATE THE REWARDING EFFECTS INDUCED BY COCAINE. OUR RESULTS SUGGEST THAT METHIONINE MAY HAVE BECOME A POTENTIAL THERAPEUTIC TARGET TO TREAT COCAINE ADDICTION. 2012 3 3314 55 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 4 5624 36 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 5 6801 65 [EPIGENETIC MECHANISMS AND ALCOHOL USE DISORDERS: A POTENTIAL THERAPEUTIC TARGET]. ALCOHOL USE DISORDER IS A DEVASTATING ILLNESS WITH A PROFOUND HEALTH IMPACT, AND ITS DEVELOPMENT IS DEPENDENT ON BOTH GENETIC AND ENVIRONMENTAL FACTORS. THIS DISEASE OCCURS OVER TIME AND REQUIRES CHANGES IN BRAIN GENE EXPRESSION. THERE IS CONVERGING EVIDENCE SUGGESTING THAT THE EPIGENETIC PROCESSES MAY PLAY A ROLE IN THE ALCOHOL-INDUCED GENE REGULATIONS AND BEHAVIOR SUCH AS THE INTERVENTION OF DNA METHYLATION AND HISTONE ACETYLATION. HISTONE ACETYLATION, LIKE HISTONE METHYLATION, IS A HIGHLY DYNAMIC PROCESS REGULATED BY TWO CLASSES OF ENZYMES: HISTONE ACETYLTRANSFERASES AND HISTONE DEACETYLASES (HDACS). TO DATE, 18 HUMAN HDAC ISOFORMS HAVE BEEN CHARACTERIZED, AND BASED ON THEIR SEQUENCE HOMOLOGIES AND COFACTOR DEPENDENCIES, THEY HAVE BEEN PHYLOGENETICALLY CATEGORIZED INTO 4 MAIN CLASSES: CLASSES I, II (A AND B), III, AND IV. IN THE BRAIN, EXPRESSION OF THE DIFFERENT CLASSES OF HDACS VARIES BETWEEN CELL TYPES AND ALSO IN THEIR SUBCELLULAR LOCALIZATION (NUCLEUS AND/OR CYTOSOL). FURTHERMORE, WE RECENTLY SHOWED THAT A SINGLE ETHANOL EXPOSURE INHIBITS HDAC ACTIVITY AND INCREASES BOTH H3 AND H4 HISTONE ACETYLATION WITHIN THE AMYGDALA OF RATS. IN THE BRAIN OF ALCOHOLIC PATIENTS, ETHANOL HAS BEEN SHOWN TO INDUCE HISTONE-RELATED AND DNA METHYLATION EPIGENETIC CHANGES IN SEVERAL REWARD REGIONS INVOLVED IN REWARD PROCESSES SUCH AS HIPPOCAMPUS, PREFRONTAL CORTEX, AND AMYGDALA. WE RECENTLY DEMONSTRATED ALTERATION OF HISTONE H3 ACETYLATION LEVELS IN SEVERAL BRAIN REGIONS FROM THE REWARD CIRCUIT OF RATS MADE DEPENDENT TO ALCOHOL AFTER CHRONIC AND INTERMITTENT EXPOSURE TO ETHANOL VAPOR. IN NEURONAL CELL LINE CULTURE, ETHANOL WAS SHOWN TO INDUCE HDAC EXPRESSION. IN MOUSE AND RAT BRAIN, NUMEROUS STUDIES REPORTED EPIGENETIC ALTERATIONS FOLLOWING ETHANOL EXPOSURE. WE ALSO DEMONSTRATED THAT BOTH THE EXPRESSION OF GENES AND THE ACTIVITY OF ENZYMES INVOLVED IN EPIGENETIC MECHANISMS ARE CHANGED AFTER REPEATED ADMINISTRATIONS OF ETHANOL IN MICE SENSITIZED TO THE MOTOR STIMULANT EFFECT OF ETHANOL (A MODEL OF DRUG-INDUCED NEUROPLASTICITY). NUMEROUS STUDIES HAVE SHOWN THAT HDAC INHIBITORS ARE ABLE TO COUNTER ETHANOL-INDUCED BEHAVIORS AND THE ETHANOL-INDUCED CHANGES IN THE LEVELS OF HDAC AND/OR LEVELS OF ACETYLATED HDAC. FOR EXAMPLE, TRICHOSTATIN A (TSA) TREATMENT CAUSED THE REVERSAL OF ETHANOL-INDUCED TOLERANCE, ANXIETY, AND ETHANOL DRINKING BY INHIBITING HDAC ACTIVITY, THEREBY INCREASING HISTONE ACETYLATION IN THE AMYGDALA OF RATS. ANOTHER STUDY DEMONSTRATED THAT TSA PREVENTED THE DEVELOPMENT OF ETHANOL WITHDRAWAL INDUCED ANXIETY IN RATS BY RESCUING DEFICITS IN HISTONE ACETYLATION INDUCED BY INCREASED HDAC ACTIVITY IN THE AMYGDALA. WE HAVE DEMONSTRATED THAT TREATMENT WITH THE HDAC INHIBITOR SODIUM BUTYRATE BLOCKS BOTH THE DEVELOPMENT AND THE EXPRESSION OF ETHANOL-INDUCED BEHAVIORAL SENSITIZATION IN MICE. IN THIS CONTEXT, CONVERGING EVIDENCE INDICATES THAT HDAC INHIBITORS COULD BE USEFUL IN COUNTERACTING ETHANOL-INDUCED GENE REGULATIONS VIA EPIGENETIC MECHANISMS, THAT IS, HDAC INHIBITORS COULD AFFECT DIFFERENT ACETYLATION SITES AND MAY ALSO ALTER THE EXPRESSION OF DIFFERENT GENES THAT COULD IN TURN COUNTERACT THE EFFECT OF ETHANOL. RECENT WORK IN RODENTS HAS SHOWN THAT SYSTEMIC ADMINISTRATION OF PAN HDAC CLASS I AND II INHIBITORS, TSA AND N-HYDROXY-N-PHENYL-OCTANEDIAMIDE [SUBEROYLANILIDE HYDROXAMIC ACID] (SAHA), AND OF THE MORE SELECTIVE INHIBITOR (MAINLY HDAC1 AND HDAC9) MS-275, DECREASE BINGE-LIKE ALCOHOL DRINKING IN MICE. SAHA SELECTIVELY REDUCED ETHANOL OPERANT SELF-ADMINISTRATION AND SEEKING IN RATS. OUR PREVIOUS STUDY REVEALED THAT MS-275 STRONGLY DECREASED OPERANT ETHANOL SELF-ADMINISTRATION IN ALCOHOL-DEPENDENT RATS WHEN ADMINISTERED 30 MINUTES BEFORE THE SESSION AT THE SECOND DAY OF INJECTION. WE ALSO DEMONSTRATED THAT INTRA-CEREBRO-VENTRICULAR INFUSION OF MS-275 INCREASES ACETYLATION OF HISTONE 4 WITHIN THE NUCLEUS ACCUMBENS AND THE DORSOLATERAL STRIATUM, ASSOCIATED TO A DECREASE IN ETHANOL SELF-ADMINISTRATION BY ABOUT 75%. MS-275 ALSO DIMINISHED BOTH THE MOTIVATION TO CONSUME ETHANOL (25% DECREASE), RELAPSE (BY ABOUT 50%) AND POSTPONED REACQUISITION AFTER ABSTINENCE. BOTH LITERATURE AND SEVERAL OF OUR STUDIES STRONGLY SUPPORT THE POTENTIAL THERAPEUTIC INTEREST OF TARGETING EPIGENETIC MECHANISMS IN EXCESSIVE ALCOHOL DRINKING AND STRENGTHEN THEINTEREST OF FOCUSING ON SPECIFIC ISOFORMS OF HISTONE DEACETYLASES. 2017 6 6207 37 THE INHIBITION OF HISTONE DEACETYLASES REDUCES THE REINSTATEMENT OF COCAINE-SEEKING BEHAVIOR IN RATS. DRUG ADDICTION IS A CHRONIC BRAIN DISEASE CHARACTERIZED BY A PERSISTENT RISK OF RELAPSE, EVEN AFTER A LONG PERIOD OF ABSTINENCE. A CURRENT HYPOTHESIS STATES THAT RELAPSE RESULTS FROM LASTING NEUROADAPTATIONS THAT ARE INDUCED IN RESPONSE TO REPEATED DRUG ADMINISTRATION. THE ADAPTATIONS REQUIRE GENE EXPRESSION, SOME OF WHICH BEING UNDER THE CONTROL OF STABLE EPIGENETIC REGULATIONS. WE HAVE PREVIOUSLY DEMONSTRATED THAT PRETREATMENT WITH HISTONE DEACETYLASE (HDAC) INHIBITORS REDUCES THE COCAINE REINFORCING PROPERTIES AS WELL AS THE MOTIVATION OF RATS FOR COCAINE. WE SHOW HERE THAT THE SAME HDAC INHIBITORS, TRICHOSTATIN A AND PHENYLBUTYRATE, SIGNIFICANTLY REDUCED THE COCAINE-SEEKING BEHAVIOR INDUCED BY THE COMBINATION OF A COCAINE INJECTION TOGETHER WITH THE EXPOSURE TO A LIGHT CUE PREVIOUSLY ASSOCIATED WITH COCAINE TAKING. REINSTATEMENT OF DRUG-SEEKING BEHAVIOR WAS CARRIED OUT AFTER A 3-WEEK WITHDRAWAL PERIOD, WHICH CAME AFTER TEN DAILY SESSIONS OF COCAINE INTRAVENOUS SELF-ADMINISTRATION. OUR RESULTS SUGGEST THAT PHARMACOLOGICAL TREATMENT AIMED AT MODULATING EPIGENETIC REGULATION, AND PARTICULARLY TREATMENT THAT WOULD INHIBIT HDAC ACTIVITY, COULD REDUCE THE RISK OF RELAPSE, A MAJOR DRAWBACK IN THE TREATMENT OF DRUG ADDICTION. 2011 7 4236 30 METHYLATION OF THE TYROSINE HYDROXYLASE GENE IS DYSREGULATED BY COCAINE DEPENDENCE IN THE HUMAN STRIATUM. COCAINE DEPENDENCE IS A CHRONIC, RELAPSING DISORDER CAUSED BY LASTING CHANGES IN THE BRAIN. ANIMAL STUDIES HAVE IDENTIFIED COCAINE-RELATED ALTERATIONS IN STRIATAL DNA METHYLATION; HOWEVER, IT IS UNCLEAR HOW METHYLATION IS RELATED TO COCAINE DEPENDENCE IN HUMANS. WE GENERATED METHYLOMIC PROFILES OF THE NUCLEUS ACCUMBENS USING HUMAN POSTMORTEM BRAINS FROM A COHORT OF INDIVIDUALS WITH COCAINE DEPENDENCE AND HEALTHY CONTROLS (N = 25 PER GROUP). WE FOUND HYPERMETHYLATION IN A CLUSTER OF CPGS WITHIN THE GENE BODY OF TYROSINE HYDROXYLASE (TH), CONTAINING A PUTATIVE BINDING SITE FOR THE EARLY GROWTH RESPONSE 1 (EGR1) TRANSCRIPTION FACTOR, WHICH IS HYPERMETHYLATED IN THE CAUDATE NUCLEUS OF COCAINE-DEPENDENT INDIVIDUALS. WE REPLICATED THIS FINDING AND FOUND IT TO BE SPECIFIC TO STRIATAL NEURONAL NUCLEI. FURTHERMORE, THIS LOCUS DEMONSTRATES ENHANCER ACTIVITY WHICH IS ATTENUATED BY METHYLATION AND ENHANCED BY EGR1 OVEREXPRESSION. THESE RESULTS SUGGEST THAT COCAINE DEPENDENCE ALTERS THE EPIGENETIC REGULATION OF DOPAMINERGIC SIGNALING GENES. 2021 8 5177 51 PREFRONTAL CORTEX EXPRESSION OF CHROMATIN MODIFIER GENES IN MALE WSP AND WSR MICE CHANGES ACROSS ETHANOL DEPENDENCE, WITHDRAWAL, AND ABSTINENCE. ALCOHOL-USE DISORDER (AUD) IS A RELAPSING DISORDER ASSOCIATED WITH EXCESSIVE ETHANOL CONSUMPTION. RECENT STUDIES SUPPORT THE INVOLVEMENT OF EPIGENETIC MECHANISMS IN THE DEVELOPMENT OF AUD. STUDIES CARRIED OUT SO FAR HAVE FOCUSED ON A FEW SPECIFIC EPIGENETIC MODIFICATIONS. THE GOAL OF THIS PROJECT WAS TO INVESTIGATE GENE EXPRESSION CHANGES OF EPIGENETIC REGULATORS THAT MEDIATE A BROAD ARRAY OF CHROMATIN MODIFICATIONS AFTER CHRONIC ALCOHOL EXPOSURE, CHRONIC ALCOHOL EXPOSURE FOLLOWED BY 8 H WITHDRAWAL, AND CHRONIC ALCOHOL EXPOSURE FOLLOWED BY 21 DAYS OF ABSTINENCE IN WITHDRAWAL-RESISTANT (WSR) AND WITHDRAWAL SEIZURE-PRONE (WSP) SELECTED MOUSE LINES. WE FOUND THAT CHRONIC VAPOR EXPOSURE TO HIGHLY INTOXICATING LEVELS OF ETHANOL ALTERS THE EXPRESSION OF SEVERAL CHROMATIN REMODELING GENES MEASURED BY QUANTITATIVE PCR ARRAY ANALYSES. THE IDENTIFIED EFFECTS WERE INDEPENDENT OF SELECTED LINES, WHICH, HOWEVER, DISPLAYED BASELINE DIFFERENCES IN EPIGENETIC GENE EXPRESSION. WE REPORTED DYSREGULATION IN THE EXPRESSION OF GENES INVOLVED IN HISTONE ACETYLATION, DEACETYLATION, LYSINE AND ARGININE METHYLATION AND UBIQUITINATIONHYLATION DURING CHRONIC ETHANOL EXPOSURE AND WITHDRAWAL, BUT NOT AFTER 21 DAYS OF ABSTINENCE. ETHANOL-INDUCED CHANGES ARE CONSISTENT WITH DECREASED HISTONE ACETYLATION AND WITH DECREASED DEPOSITION OF THE PERMISSIVE UBIQUITINATION MARK H2BK120UB, ASSOCIATED WITH REDUCED TRANSCRIPTION. ON THE OTHER HAND, ETHANOL-INDUCED CHANGES IN THE EXPRESSION OF GENES INVOLVED IN HISTONE LYSINE METHYLATION ARE CONSISTENT WITH INCREASED TRANSCRIPTION. THE NET RESULT OF THESE MODIFICATIONS ON GENE EXPRESSION IS LIKELY TO DEPEND ON THE COMBINATION OF THE SPECIFIC HISTONE TAIL MODIFICATIONS PRESENT AT A GIVEN TIME ON A GIVEN PROMOTER. SINCE ALCOHOL DOES NOT MODULATE GENE EXPRESSION UNIDIRECTIONALLY, IT IS NOT SURPRISING THAT ALCOHOL DOES NOT UNIDIRECTIONALLY ALTER CHROMATIN STRUCTURE TOWARD A CLOSED OR OPEN STATE, AS SUGGESTED BY THE RESULTS OF THIS STUDY. 2017 9 2325 42 EPIGENETIC REGULATION OF HIPPOCAMPAL FOSB EXPRESSION CONTROLS BEHAVIORAL RESPONSES TO COCAINE. DRUG ADDICTION RESULTS IN PART FROM MALADAPTIVE LEARNING, INCLUDING THE FORMATION OF STRONG ASSOCIATIONS BETWEEN THE DRUG AND THE CIRCUMSTANCES OF CONSUMPTION. HOWEVER, DRUG-INDUCED CHANGES IN GENE EXPRESSION UNDERLYING THE SALIENCY OF THESE ASSOCIATIONS REMAIN UNDERSTUDIED. CONSOLIDATION OF EXPLICIT MEMORIES OCCURS WITHIN THE HIPPOCAMPUS, AND WE HAVE SHOWN THAT SPATIAL LEARNING INDUCES EXPRESSION OF THE TRANSCRIPTION FACTOR DELTAFOSB IN HIPPOCAMPUS AND THAT THIS INDUCTION IS CRITICAL FOR LEARNING. DRUGS OF ABUSE ALSO UPREGULATE DELTAFOSB IN HIPPOCAMPUS, BUT THE MECHANISM OF ITS INDUCTION BY COCAINE AND ITS ROLE IN HIPPOCAMPUS-DEPENDENT COCAINE RESPONSES IS UNKNOWN. WE INVESTIGATED DIFFERENCES IN MOUSE DORSAL AND VENTRAL HIPPOCAMPAL DELTAFOSB EXPRESSION IN RESPONSE TO CHRONIC COCAINE, BECAUSE THESE REGIONS APPEAR TO REGULATE DISTINCT COCAINE-RELATED BEHAVIORS. WE FOUND THAT COCAINE-MEDIATED INDUCTION OF DELTAFOSB WAS SUBREGION-SPECIFIC, AND THAT DELTAFOSB TRANSCRIPTIONAL ACTIVITY IN BOTH THE DORSAL AND VENTRAL HIPPOCAMPUS IS NECESSARY FOR COCAINE CONDITIONED PLACE PREFERENCE. FURTHER, WE CHARACTERIZE CHANGES IN HISTONE MODIFICATIONS AT THE FOSB PROMOTER IN HIPPOCAMPUS IN RESPONSE TO CHRONIC COCAINE AND FOUND THAT LOCUS-SPECIFIC EPIGENETIC MODIFICATION IS ESSENTIAL FOR FOSB INDUCTION AND MULTIPLE HIPPOCAMPUS-DEPENDENT BEHAVIORS, INCLUDING COCAINE PLACE PREFERENCE. COLLECTIVELY, THESE FINDINGS SUGGEST THAT EXPOSURE TO COCAINE INDUCES HISTONE MODIFICATION AT THE HIPPOCAMPAL FOSB GENE PROMOTER TO CAUSE DELTAFOSB INDUCTION CRITICAL FOR COCAINE-RELATED LEARNING.SIGNIFICANCE STATEMENT ALTHOUGH COCAINE ADDICTION IS DRIVEN IN PART BY THE FORMATION OF INDELIBLE ASSOCIATIONS BETWEEN THE DRUG AND THE ENVIRONMENT, PARAPHERNALIA, AND CIRCUMSTANCES OF USE, AND ALTHOUGH THIS TYPE OF ASSOCIATIVE LEARNING IS DEPENDENT UPON CHANGES IN GENE EXPRESSION IN A BRAIN REGION CALLED THE HIPPOCAMPUS, THE MECHANISMS BY WHICH COCAINE ALTERS HIPPOCAMPAL GENE EXPRESSION TO DRIVE FORMATION OF THESE ASSOCIATIONS IS POORLY UNDERSTOOD. HERE, WE DEMONSTRATE THAT CHRONIC COCAINE ENGAGES LOCUS-SPECIFIC CHANGES IN THE EPIGENETIC PROFILE OF THE FOSB GENE IN THE HIPPOCAMPUS, AND THAT THESE ALTERATIONS ARE REQUIRED FOR COCAINE-DEPENDENT GENE EXPRESSION AND COCAINE-ENVIRONMENT ASSOCIATIONS. THIS WORK PROVIDES NOVEL INSIGHT INTO ADDICTION ETIOLOGY AND POTENTIAL INROADS FOR THERAPEUTIC INTERVENTION IN COCAINE ADDICTION. 2019 10 882 42 CHRONIC COCAINE-INDUCED H3 ACETYLATION AND TRANSCRIPTIONAL ACTIVATION OF CAMKIIALPHA IN THE NUCLEUS ACCUMBENS IS CRITICAL FOR MOTIVATION FOR DRUG REINFORCEMENT. THE REGULATION OF GENE EXPRESSION IN THE BRAIN REWARD REGIONS IS KNOWN TO CONTRIBUTE TO THE PATHOGENESIS AND PERSISTENCE OF DRUG ADDICTION. INCREASING EVIDENCE SUGGESTS THAT THE REGULATION OF GENE TRANSCRIPTION IS MEDIATED BY EPIGENETIC MECHANISMS THAT ALTER THE CHROMATIN STRUCTURE AT SPECIFIC GENE PROMOTERS. TO BETTER UNDERSTAND THE INVOLVEMENT OF EPIGENETIC REGULATION IN DRUG REINFORCEMENT PROPERTIES, RATS WERE SUBJECTED TO COCAINE SELF-ADMINISTRATION PARADIGM. DAILY HISTONE DEACETYLASE (HDAC) INHIBITOR INFUSIONS IN THE SHELL OF THE NUCLEUS ACCUMBENS (NAC) CAUSED AN UPWARD SHIFT IN THE DOSE-RESPONSE CURVE UNDER FIXED-RATIO SCHEDULE AND INCREASED THE BREAK POINT UNDER PROGRESSIVE-RATIO SCHEDULE, INDICATING ENHANCED MOTIVATION FOR SELF-ADMINISTERED DRUG. THE EFFECT OF THE HDAC INHIBITOR IS ATTRIBUTED TO THE INCREASED ELEVATION OF HISTONE ACETYLATION INDUCED BY CHRONIC, BUT NOT ACUTE, COCAINE EXPERIENCE. IN CONTRAST, NEUTRALIZING THE CHRONIC COCAINE-INDUCED INCREASE IN HISTONE MODIFICATION BY THE BILATERAL OVEREXPRESSION OF HDAC4 IN THE NAC SHELL REDUCED DRUG MOTIVATION. THE ASSOCIATION BETWEEN THE MOTIVATION FOR COCAINE AND THE TRANSCRIPTIONAL ACTIVATION OF ADDICTION-RELATED GENES BY H3 ACETYLATION IN THE NAC SHELL WAS ANALYZED. AMONG THE GENES ACTIVATED BY CHRONIC COCAINE EXPERIENCES, THE EXPRESSION OF CAMKIIALPHA, BUT NOT CAMKIIBETA, CORRELATED POSITIVELY WITH MOTIVATION FOR THE DRUG. LENTIVIRUS-MEDIATED SHRNA KNOCKDOWN EXPERIMENTS SHOWED THAT CAMKIIALPHA, BUT NOT CAMKIIBETA, IN THE NAC SHELL IS ESSENTIAL FOR THE MAINTENANCE OF MOTIVATION TO SELF-ADMINISTERED COCAINE. THESE FINDINGS SUGGEST THAT CHRONIC DRUG-USE-INDUCED TRANSCRIPTIONAL ACTIVATION OF GENES, SUCH AS CAMKIIALPHA, MODULATED BY H3 ACETYLATION IN THE NAC IS A CRITICAL REGULATORY MECHANISM UNDERLYING MOTIVATION FOR DRUG REINFORCEMENT. 2010 11 3315 46 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 12 6175 35 THE HISTONE DEACETYLASE INHIBITOR SUBEROYLANILIDE HYDROXAMIC ACID (SAHA) ALLEVIATES DEPRESSION-LIKE BEHAVIOR AND NORMALIZES EPIGENETIC CHANGES IN THE HIPPOCAMPUS DURING ETHANOL WITHDRAWAL. WITHDRAWAL FROM CHRONIC ALCOHOL DRINKING CAN CAUSE DEPRESSION, LEADING TO AN INABILITY TO FUNCTION IN DAILY LIFE AND AN INCREASED RISK FOR RELAPSE TO HARMFUL DRINKING. UNDERSTANDING THE CAUSES OF ALCOHOL WITHDRAWAL-RELATED DEPRESSION MAY LEAD TO NEW THERAPEUTIC TARGETS FOR TREATMENT. EPIGENETIC FACTORS HAVE RECENTLY EMERGED AS IMPORTANT CONTRIBUTORS TO BOTH DEPRESSION AND ALCOHOL USE DISORDER (AUD). SPECIFICALLY, ACETYLATION OF THE N-TERMINAL TAILS OF HISTONE PROTEINS THAT PACKAGE DNA INTO NUCLEOSOMES IS ALTERED IN STRESS-INDUCED MODELS OF DEPRESSION AND DURING ALCOHOL WITHDRAWAL. THE GOAL OF THIS STUDY WAS TO EXAMINE DEPRESSION-LIKE BEHAVIOR DURING ALCOHOL WITHDRAWAL AND ASSOCIATED CHANGES IN HISTONE ACETYLATION AND EXPRESSION OF HISTONE DEACETYLASE 2 (HDAC2) IN THE HIPPOCAMPUS, A BRAIN REGION CRITICAL FOR MOOD REGULATION AND DEPRESSION. MALE SPRAGUE-DAWLEY RATS WERE TREATED WITH THE LIEBER-DECARLI ETHANOL LIQUID DIET FOR 15 DAYS AND THEN UNDERWENT WITHDRAWAL. RATS WERE TREATED WITH THE HDAC INHIBITOR, SUBEROYLANILIDE HYDROXAMIC ACID (SAHA), DURING WITHDRAWAL AND WERE TESTED FOR DEPRESSION-LIKE BEHAVIOR. IN A SEPARATE GROUP OF RATS, THE HIPPOCAMPUS WAS ANALYZED FOR MRNA AND PROTEIN EXPRESSION OF HDAC2 AND LEVELS OF HISTONE H3 LYSINE 9 ACETYLATION (H3K9AC) DURING CHRONIC ETHANOL EXPOSURE AND WITHDRAWAL. RATS UNDERGOING ETHANOL WITHDRAWAL EXHIBITED DEPRESSION-LIKE BEHAVIOR AND HAD INCREASED HDAC2 AND DECREASED H3K9AC LEVELS IN SPECIFIC STRUCTURES OF THE HIPPOCAMPUS. TREATMENT WITH SAHA DURING WITHDRAWAL AMELIORATED DEPRESSION-LIKE BEHAVIOR AND NORMALIZED CHANGES IN HIPPOCAMPAL HDAC2 AND H3K9AC LEVELS. THESE RESULTS DEMONSTRATE THAT ETHANOL WITHDRAWAL CAUSES AN ALTERED EPIGENETIC STATE IN THE HIPPOCAMPUS. TREATMENT WITH AN HDAC INHIBITOR CAN CORRECT THIS STATE AND ALLEVIATE DEPRESSION-LIKE SYMPTOMS DEVELOPED DURING WITHDRAWAL. TARGETING HISTONE ACETYLATION MAY BE A NOVEL STRATEGY TO REDUCE ETHANOL WITHDRAWAL-INDUCED DEPRESSION. 2019 13 1614 37 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 14 1789 31 EFFECT OF CHRONIC HEROIN AND COCAINE ADMINISTRATION ON GLOBAL DNA METHYLATION IN BRAIN AND LIVER. DRUG ABUSE IS ASSOCIATED WITH EPIGENETIC CHANGES, SUCH AS HISTONE MODIFICATIONS AND DNA METHYLATION. THE PURPOSE OF THE PRESENT STUDY WAS TO EXAMINE THE EFFECT OF CHRONIC COCAINE AND HEROIN ADMINISTRATION ON GLOBAL DNA METHYLATION IN BRAIN AND LIVER. MALE, 8 WEEK OLD, C57BL/6J MICE RECEIVED HEROIN IN A CHRONIC 'INTERMITTENT' ESCALATING DOSE PARADIGM, OR COCAINE IN A CHRONIC ESCALATING DOSE 'BINGE' PARADIGM, WHICH MIMIC THE HUMAN PATTERN OF OPIOID OR COCAINE ABUSE RESPECTIVELY. FOLLOWING SACRIFICE, LIVERS AND BRAINS WERE REMOVED AND DNA WAS EXTRACTED FROM THEM. THE EXTRACTED DNA WAS HYDROLYZED AND 2'-DEOXYCYTIDINE AND 5-METHYL-2'-DEOXYCYTIDINE WERE DETERMINED BY HPLC-UV. THE % 5-METHYL-2'-DEOXYCYTIDINE CONTENT OF DNA WAS SIGNIFICANTLY HIGHER IN THE BRAIN COMPARED TO THE LIVER. THERE WERE NO DIFFERENCES BETWEEN THE CONTROL ANIMALS AND THE COCAINE OR HEROIN TREATED ANIMALS IN NEITHER OF THE TISSUES EXAMINED, WHICH IS SURPRISING SINCE COCAINE ADMINISTRATION INDUCED GROSS MORPHOLOGICAL CHANGES IN THE LIVER. MOREOVER, THERE WAS NO DIFFERENCE IN THE % 5-METHYL-2'-DEOXYCYTIDINE CONTENT OF DNA BETWEEN THE COCAINE AND THE HEROIN TREATED ANIMALS. THE GLOBAL DNA METHYLATION STATUS IN THE BRAIN AND LIVER OF MICE CHRONICALLY TREATED WITH COCAINE OR HEROIN REMAINS UNAFFECTED, BUT THIS FINDING CANNOT EXCLUDE THE EXISTENCE OF ANATOMICAL REGION OR GENE-SPECIFIC METHYLATION DIFFERENCES. THIS IS THE FIRST TIME THAT GLOBAL DNA METHYLATION IN THE LIVER AND WHOLE BRAIN HAS BEEN STUDIED FOLLOWING CHRONIC COCAINE OR HEROIN TREATMENT. 2013 15 5019 42 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 16 1808 48 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 17 4173 44 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 18 4878 56 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 19 883 43 CHRONIC COCAINE-REGULATED EPIGENOMIC CHANGES IN MOUSE NUCLEUS ACCUMBENS. BACKGROUND: INCREASING EVIDENCE SUPPORTS A ROLE FOR ALTERED GENE EXPRESSION IN MEDIATING THE LASTING EFFECTS OF COCAINE ON THE BRAIN, AND RECENT WORK HAS DEMONSTRATED THE INVOLVEMENT OF CHROMATIN MODIFICATIONS IN THESE ALTERATIONS. HOWEVER, ALL SUCH STUDIES TO DATE HAVE BEEN RESTRICTED BY THEIR RELIANCE ON MICROARRAY TECHNOLOGIES THAT HAVE INTRINSIC LIMITATIONS. RESULTS: WE USE NEXT GENERATION SEQUENCING METHODS, RNA-SEQ AND CHIP-SEQ FOR RNA POLYMERASE II AND SEVERAL HISTONE METHYLATION MARKS, TO OBTAIN A MORE COMPLETE VIEW OF COCAINE-INDUCED CHANGES IN GENE EXPRESSION AND ASSOCIATED ADAPTATIONS IN NUMEROUS MODES OF CHROMATIN REGULATION IN THE MOUSE NUCLEUS ACCUMBENS, A KEY BRAIN REWARD REGION. WE DEMONSTRATE AN UNEXPECTEDLY LARGE NUMBER OF PRE-MRNA SPLICING ALTERATIONS IN RESPONSE TO REPEATED COCAINE TREATMENT. IN ADDITION, WE IDENTIFY COMBINATIONS OF CHROMATIN CHANGES, OR SIGNATURES, THAT CORRELATE WITH COCAINE-DEPENDENT REGULATION OF GENE EXPRESSION, INCLUDING THOSE INVOLVING PRE-MRNA ALTERNATIVE SPLICING. THROUGH BIOINFORMATIC PREDICTION AND BIOLOGICAL VALIDATION, WE IDENTIFY ONE PARTICULAR SPLICING FACTOR, A2BP1(RBFOX1/FOX-1), WHICH IS ENRICHED AT GENES THAT DISPLAY CERTAIN CHROMATIN SIGNATURES AND CONTRIBUTES TO DRUG-INDUCED BEHAVIORAL ABNORMALITIES. TOGETHER, THIS DELINEATION OF THE COCAINE-INDUCED EPIGENOME IN THE NUCLEUS ACCUMBENS REVEALS SEVERAL NOVEL MODES OF REGULATION BY WHICH COCAINE ALTERS THE BRAIN. CONCLUSIONS: WE ESTABLISH COMBINATORIAL CHROMATIN AND TRANSCRIPTIONAL PROFILES IN MOUSE NUCLEUS ACCUMBENS AFTER REPEATED COCAINE TREATMENT. THESE RESULTS SERVE AS AN IMPORTANT RESOURCE FOR THE FIELD AND PROVIDE A TEMPLATE FOR THE ANALYSIS OF OTHER SYSTEMS TO REVEAL NEW TRANSCRIPTIONAL AND EPIGENETIC MECHANISMS OF NEURONAL REGULATION. 2014 20 213 41 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