1 4150 147 MECHANISTIC INSIGHTS INTO EPIGENETIC MODULATION OF ETHANOL CONSUMPTION. THERE IS GROWING EVIDENCE THAT SMALL-MOLECULE INHIBITORS OF EPIGENETIC MODULATORS, SUCH AS HISTONE DEACETYLASES (HDAC) AND DNA METHYLTRANSFERASES (DNMT), CAN REDUCE VOLUNTARY ETHANOL CONSUMPTION IN ANIMAL MODELS, BUT MOLECULAR AND CELLULAR PROCESSES UNDERLYING THIS BEHAVIORAL EFFECT ARE POORLY UNDERSTOOD. WE USED C57BL/6J MALE MICE TO INVESTIGATE THE EFFECTS OF TWO FDA-APPROVED DRUGS, DECITABINE (A DNMT INHIBITOR) AND SAHA (AN HDAC INHIBITOR), ON ETHANOL CONSUMPTION USING TWO TESTS: BINGE-LIKE DRINKING IN THE DARK (DID) AND CHRONIC INTERMITTENT EVERY OTHER DAY (EOD) DRINKING. DECITABINE BUT NOT SAHA REDUCED ETHANOL CONSUMPTION IN BOTH TESTS. WE FURTHER INVESTIGATED DECITABINE'S EFFECTS ON THE BRAIN'S REWARD PATHWAY BY GENE EXPRESSION PROFILING IN THE VENTRAL TEGMENTAL AREA (VTA), USING RNA SEQUENCING AND ELECTROPHYSIOLOGICAL RECORDINGS FROM VTA DOPAMINERGIC NEURONS. DECITABINE-INDUCED DECREASES IN EOD DRINKING WERE ASSOCIATED WITH GLOBAL CHANGES IN GENE EXPRESSION, IMPLICATING REGULATION OF CEREBRAL BLOOD FLOW, EXTRACELLULAR MATRIX ORGANIZATION, AND NEUROIMMUNE FUNCTIONS IN DECITABINE ACTIONS. IN ADDITION, AN IN VIVO ADMINISTRATION OF DECITABINE SHORTENED ETHANOL-INDUCED EXCITATION OF VTA DOPAMINERGIC NEURONS IN VITRO, SUGGESTING THAT DECITABINE REDUCES ETHANOL DRINKING VIA CHANGES IN THE REWARD PATHWAY. TAKEN TOGETHER, OUR DATA SUGGEST A CONTRIBUTION OF BOTH NEURONAL AND NON-NEURONAL MECHANISMS IN THE VTA IN THE REGULATION OF ETHANOL CONSUMPTION. DECITABINE AND OTHER EPIGENETIC COMPOUNDS HAVE BEEN APPROVED FOR CANCER TREATMENT, AND UNDERSTANDING THEIR MECHANISMS OF ACTIONS IN THE BRAIN MAY ASSIST IN REPURPOSING THESE DRUGS AND DEVELOPING NOVEL THERAPIES FOR CENTRAL DISORDERS, INCLUDING DRUG ADDICTION. 2017 2 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 3 5624 40 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 4 6175 48 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 5 2013 46 EPIGENETIC BASIS OF THE DARK SIDE OF ALCOHOL ADDICTION. ALCOHOLISM IS A COMPLEX BRAIN DISEASE CHARACTERIZED BY THREE DISTINCT STAGES OF THE ADDICTION CYCLE THAT MANIFEST AS NEUROADAPTIVE CHANGES IN THE BRAIN. ONE SUCH STAGE OF THE ADDICTION CYCLE IS ALCOHOL WITHDRAWAL AND THE NEGATIVE AFFECTIVE STATES THAT PROMOTE DRINKING AND MAINTAIN ADDICTION. REPEATED ALCOHOL USE, GENETIC PREDISPOSITION TO ALCOHOLISM AND ANXIETY, AND ALCOHOL EXPOSURE DURING CRUCIAL DEVELOPMENTAL PERIODS ALL CONTRIBUTE TO THE DEVELOPMENT OF ALCOHOL-INDUCED WITHDRAWAL AND NEGATIVE AFFECTIVE SYMPTOMS. EPIGENETIC MODIFICATIONS WITHIN THE AMYGDALA HAVE PROVIDED A MOLECULAR BASIS OF THESE NEGATIVE AFFECTIVE SYMPTOMS, ALSO KNOWN AS THE DARK SIDE OF ADDICTION. HERE, WE PROPOSE THAT ALLOSTATIC CHANGE WITHIN THE EPIGENOME IN THE AMYGDALA IS A PRIME MECHANISM OF THE BIOLOGICAL BASIS OF NEGATIVE AFFECTIVE STATES RESULTING FROM, AND CONTRIBUTING TO, ALCOHOLISM. ACUTE ALCOHOL EXPOSURE PRODUCES AN ANXIOLYTIC RESPONSE WHICH IS ASSOCIATED WITH THE OPENING OF CHROMATIN DUE TO INCREASED HISTONE ACETYLATION, INCREASED CREB BINDING PROTEIN (CBP) LEVELS, AND HISTONE DEACETYLASE (HDAC) INHIBITION. AFTER CHRONIC ETHANOL EXPOSURE, THESE CHANGES RETURN TO BASELINE ALONG WITH ANXIETY-LIKE BEHAVIORS. HOWEVER, DURING WITHDRAWAL, HISTONE ACETYLATION DECREASES DUE TO INCREASED HDAC ACTIVITY AND DECREASED CBP LEVELS IN THE AMYGDALA CIRCUITRY LEADING TO THE DEVELOPMENT OF ANXIETY-LIKE BEHAVIORS. ADDITIONALLY, INNATELY HIGHER EXPRESSION OF THE HDAC2 ISOFORM LEADS TO A DEFICIT IN GLOBAL AND GENE-SPECIFIC HISTONE ACETYLATION IN THE AMYGDALA THAT IS ASSOCIATED WITH A DECREASE IN THE EXPRESSION OF SEVERAL SYNAPTIC PLASTICITY-ASSOCIATED GENES AND MAINTAINING HEIGHTENED ANXIETY-LIKE BEHAVIOR AND EXCESSIVE ALCOHOL INTAKE. ADOLESCENT ALCOHOL EXPOSURE ALSO LEADS TO HIGHER EXPRESSION OF HDAC2 AND A DEFICIT IN HISTONE ACETYLATION LEADING TO DECREASED EXPRESSION OF SYNAPTIC PLASTICITY-ASSOCIATED GENES AND HIGH ANXIETY AND DRINKING BEHAVIOR IN ADULTHOOD. ALL THESE STUDIES INDICATE THAT THE EPIGENOME CAN UNDERGO ALLOSTATIC REPROGRAMMING IN THE AMYGDALOID CIRCUITRY DURING VARIOUS STAGES OF ALCOHOL EXPOSURE. FURTHERMORE, OPENING THE CHROMATIN BY INHIBITING HDACS USING PHARMACOLOGICAL OR GENETIC MANIPULATIONS CAN LEAD TO THE ATTENUATION OF ANXIETY AS WELL AS ALCOHOL INTAKE. CHROMATIN REMODELING PROVIDES A CLEAR BIOLOGICAL BASIS FOR THE NEGATIVE AFFECTIVE STATES SEEN DURING ALCOHOL ADDICTION AND PRESENTS OPPORTUNITIES FOR NOVEL DRUG DEVELOPMENT AND TREATMENT OPTIONS. THIS ARTICLE IS PART OF THE SPECIAL ISSUE ENTITLED "ALCOHOLISM". 2017 6 2156 56 EPIGENETIC MECHANISMS ARE INVOLVED IN THE REGULATION OF ETHANOL CONSUMPTION IN MICE. BACKGROUND: REPEATED ALCOHOL EXPOSURE IS KNOWN TO INCREASE SUBSEQUENT ETHANOL CONSUMPTION IN MICE. HOWEVER, THE UNDERLYING MECHANISMS HAVE NOT BEEN FULLY ELUCIDATED. ONE POSTULATED MECHANISM INVOLVES EPIGENETIC MODIFICATIONS, INCLUDING HISTONE MODIFICATIONS AND DNA METHYLATION OF RELEVANT GENES SUCH AS NR2B OR BDNF. METHODS: TO INVESTIGATE THE ROLE OF EPIGENETIC MECHANISMS IN THE DEVELOPMENT OF ALCOHOL DRINKING BEHAVIOR, AN ESTABLISHED CHRONIC INTERMITTENT ETHANOL EXPOSURE REINFORCED ETHANOL DRINKING MOUSE MODEL WITH VAPOR INHALATION OVER TWO 9-DAY TREATMENT REGIMENS WAS USED. THE DNA METHYLTRANSFERASE INHIBITOR, 5-AZACYTIDINE OR THE HISTONE DEACETYLASE INHIBITOR, TRICHOSTATIN A WAS ADMINISTERED (INTRAPERITONEALLY) TO C57BL/6 MICE 30 MIN BEFORE DAILY EXPOSURE TO CHRONIC INTERMITTENT ETHANOL. CHANGES IN ETHANOL CONSUMPTION WERE MEASURED USING THE 2-BOTTLE CHOICE TEST. RESULTS: THE RESULTS INDICATED THAT SYSTEMIC ADMINISTRATION OF TRICHOSTATIN A (2.5 MICROG/G) FACILITATED CHRONIC INTERMITTENT ETHANOL-INDUCED ETHANOL DRINKING, BUT SYSTEMIC ADMINISTRATION OF 5-AZACYTIDINE (2 MICROG/G) DID NOT CAUSE THE SAME EFFECT. HOWEVER, WHEN 5-AZACYTIDINE WAS ADMINISTERED BY INTRACEREBROVENTRICULAR INJECTION, IT FACILITATED CHRONIC INTERMITTENT ETHANOL-INDUCED ETHANOL DRINKING. FURTHERMORE, THE INCREASED DRINKING CAUSED BY CHRONIC INTERMITTENT ETHANOL WAS PREVENTED BY INJECTION OF A METHYL DONOR, S-ADENOSYL-L-METHIONINE. TO PROVIDE EVIDENCE THAT CHRONIC INTERMITTENT ETHANOL- OR TRICHOSTATIN A-INDUCED DNA DEMETHYLATION AND HISTONE MODIFICATIONS OF THE NR2B PROMOTER MAY UNDERLIE THE ALTERED ETHANOL CONSUMPTION, WE EXAMINED EPIGENETIC MODIFICATIONS AND NR2B EXPRESSION IN THE PREFRONTAL CORTEX OF THESE MICE. CHRONIC INTERMITTENT ETHANOL OR TRICHOSTATIN A DECREASED DNA METHYLATION AND INCREASED HISTONE ACETYLATION IN THE NR2B GENE PROMOTER, AS WELL AS MRNA LEVELS OF NR2B IN THESE MICE. CONCLUSIONS: TAKEN TOGETHER, THESE RESULTS INDICATE THAT EPIGENETIC MODIFICATIONS ARE INVOLVED IN REGULATING ETHANOL DRINKING BEHAVIOR, PARTIALLY THROUGH ALTERING NR2B EXPRESSION. 2014 7 5177 42 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 8 2280 49 EPIGENETIC REGULATION IN DRUG ADDICTION. THE INTERACTION BETWEEN ENVIRONMENTAL SIGNALS AND GENES HAS NOW TAKEN ON A CLEAR MOLECULAR FORM AS DEMONSTRATED BY STABLE CHANGES IN CHROMATIN STRUCTURE. THESE CHANGES OCCUR THROUGH ACTIVATION OR REPRESSION OF SPECIFIC GENE PROGRAMMES BY A COMBINATION OF CHROMATIN REMODELLING, ACTIVATION AND ENZYMATIC MODIFICATION OF DNA AND HISTONES AS WELL AS NUCLEOSOMAL SUBUNIT EXCHANGE. RECENT RESEARCH INVESTIGATING THE MOLECULAR MECHANISMS CONTROLLING DRUG-INDUCED TRANSCRIPTIONAL, BEHAVIOURAL AND SYNAPTIC ACTIVITY HAS SHOWN A DIRECT ROLE FOR CHROMATIN REMODELLING--TERMED AS EPIGENETIC REGULATION--OF NEURONAL GENE PROGRAMMES AND SUBSEQUENT ADDICTIVE BEHAVIOUR ARISING FROM IT. RECENT DATA SUGGEST THAT REPEATED EXPOSURE TO CERTAIN DRUGS PROMOTES CHANGES IN LEVELS OF HISTONE ACETYLATION, PHOSPHORYLATION AND METHYLATION, TOGETHER WITH ALTERATIONS IN DNA METHYLATION LEVELS IN THE NEURONS OF THE BRAIN REWARD CENTRE, LOCALISED IN THE NUCLEUS ACCUMBENS (NAC) REGION OF THE LIMBIC SYSTEM. THE COMBINATION OF ACETYLATING, PHOSPHORYLATING AND METHYLATING H3 AND H4 HISTONE TAILS ALTER CHROMATIN COMPACTION THEREBY PROMOTING ALTERED LEVELS OF CELLULAR GENE EXPRESSION. HISTONE MODIFICATIONS, WHICH WEAKEN HISTONE INTERACTION WITH DNA OR THAT PROMOTE RECRUITMENT OF TRANSCRIPTIONAL ACTIVATING COMPLEXES, CORRELATE WITH PERMISSIVE GENE EXPRESSION. HISTONE DEACETYLATION, (WHICH STRENGTHEN HISTONE: DNA CONTACTS), OR HISTONE METHYLATION, (WHICH RECRUITS REPRESSIVE COMPLEXES TO CHROMATIN), PROMOTE A STATE OF TRANSCRIPTIONAL REPRESSION. USING ANIMAL MODELS, ACUTE COCAINE TREATMENT INCREASES H4 ACETYLATION AT ACUTELY REGULATED GENE PROMOTERS, WHEREAS H3 ACETYLATION APPEARS TO PREDOMINATE AT CHRONICALLY INDUCED PROMOTERS. CHRONIC COCAINE AND ALCOHOL TREATMENT ACTIVATE AND REPRESS MANY GENES SUCH AS FOSB, CDK5, AND BDNF, WHERE THEIR DYSREGULATION, AT THE CHROMATIN LEVEL, CONTRIBUTE TO THE DEVELOPMENT AND MAINTENANCE OF ADDICTION. FOLLOWING DRUG EXPOSURE, IT IS STILL UNKNOWN, HOWVER, HOW LONG THESE CHANGES IN CHROMATIN STRUCTURE PERSIST IN AFFECTING NEURONAL FUNCTION, BUT SOME DO SO FOR LIFE. 2012 9 5444 50 REPEATED TOLUENE EXPOSURE MODIFIES THE ACETYLATION PATTERN OF HISTONES H3 AND H4 IN THE RAT BRAIN. TOLUENE IS A VOLATILE ORGANIC SOLVENT WITH ADDICTIVE POTENTIAL THAT EXHIBITS SIMILARITIES IN ITS PHYSIOLOGICAL EFFECTS AND MODES OF ACTION TO OTHER ADDICTIVE DRUGS. DESPITE ITS WIDESPREAD ABUSE, THE MOLECULAR MECHANISMS DRIVING THE RESPONSE AND ADAPTATION OF THE ORGANISM TO THIS DRUG ARE NOT FULLY UNDERSTOOD. IN RECENT YEARS, DIFFERENT EPIGENETIC MECHANISMS THAT MODULATE GENE EXPRESSION HAVE BEEN SHOWN TO BE ASSOCIATED TO COCAINE, AMPHETAMINE AND ALCOHOL MISUSE-INDUCED ALTERATIONS IN NEURONAL FUNCTION. FOR EXAMPLE, IT HAS BEEN DEMONSTRATED THAT DRUG CONSUMPTION INDUCES VARIATIONS IN HISTONE ACETYLATION LEVELS IN BRAIN REWARD REGIONS AND THESE PLAY A RELEVANT ROLE ON THE ABUSE-ASSOCIATED BEHAVIORAL PLASTICITY. IN ORDER TO DECIPHER WHETHER REPEATED TOLUENE EXPOSURE COULD MEDIATE EPIGENETIC CHANGES IN THE RAT BRAIN, WE HERE ANALYZED THE ACETYLATION PATTERN OF HISTONES H3 AND H4 IN THREE BRAIN AREAS THAT HAVE BEEN PREVIOUSLY ASSOCIATED TO SUBSTANCE ABUSE REWARD PATHWAYS: THE NUCLEUS ACCUMBENS (NAC), THE VENTRAL TEGMENTAL AREA (VTA) AND THE CENTRAL AMYGDALA (CEA). USING IMMUNOFLUORESCENCE ANALYSIS OF BRAIN SECTIONS WITH SPECIFIC ANTIBODIES THAT RECOGNIZE THE ACETYLATED FORMS OF HISTONES H3 AND H4, WE DEMONSTRATE THAT CHRONIC TOLUENE INHALATION DIFFERENTIALLY MODIFIES HISTONE H3 AND H4 ACETYLATION IN THE NAC AND THE VTA WHILE NO EFFECT IS OBSERVED IN THE CEA. OUR RESULTS SUGGEST THAT THE ACTIVITY OF CHROMATIN-MODIFYING ENZYMES SUCH AS HISTONE DE-ACETYLASES (HDACS) IN CERTAIN BRAIN AREAS ARE RESPONSIVE TO TOLUENE INHALATION AND MIGHT BE CRUCIAL MEDIATORS IN THE ADDICTIVE RESPONSE TO TOLUENE. 2011 10 3587 42 IMPACT OF TLR4 ON BEHAVIORAL AND COGNITIVE DYSFUNCTIONS ASSOCIATED WITH ALCOHOL-INDUCED NEUROINFLAMMATORY DAMAGE. TOLL-LIKE RECEPTORS (TLRS) PLAY AN IMPORTANT ROLE IN THE INNATE IMMUNE RESPONSE, AND EMERGING EVIDENCE INDICATES THEIR ROLE IN BRAIN INJURY AND NEURODEGENERATION. OUR RECENT RESULTS HAVE DEMONSTRATED THAT ETHANOL IS CAPABLE OF ACTIVATING GLIAL TLR4 RECEPTORS AND THAT THE ELIMINATION OF THESE RECEPTORS IN MICE PROTECTS AGAINST ETHANOL-INDUCED GLIAL ACTIVATION, INDUCTION OF INFLAMMATORY MEDIATORS AND APOPTOSIS. THIS STUDY WAS DESIGNED TO ASSESS WHETHER ETHANOL-INDUCED INFLAMMATORY DAMAGE CAUSES BEHAVIORAL AND COGNITIVE CONSEQUENCES, AND IF BEHAVIORAL ALTERATIONS ARE DEPENDENT OF TLR4 FUNCTIONS. HERE WE SHOW IN MICE DRINKING ALCOHOL FOR 5MONTHS, FOLLOWED BY A 15-DAY WITHDRAWAL PERIOD, THAT ACTIVATION OF THE ASTROGLIAL AND MICROGLIAL CELLS IN FRONTAL CORTEX AND STRIATUM IS MAINTAINED AND THAT THESE EVENTS ARE ASSOCIATED WITH COGNITIVE AND ANXIETY-RELATED BEHAVIORAL IMPAIRMENTS IN WILD-TYPE (WT) MICE, AS DEMONSTRATED BY TESTING THE ANIMALS WITH OBJECT MEMORY RECOGNITION, CONDITIONED TASTE AVERSION AND DARK AND LIGHT BOX ANXIETY TASKS. MICE LACKING TLR4 RECEPTORS ARE PROTECTED AGAINST ETHANOL-INDUCED INFLAMMATORY DAMAGE, AND BEHAVIORAL ASSOCIATED EFFECTS. WE FURTHER ASSESS THE POSSIBILITY OF THE EPIGENETIC MODIFICATIONS PARTICIPATING IN SHORT- OR LONG-TERM BEHAVIORAL EFFECTS ASSOCIATED WITH NEUROINFLAMMATORY DAMAGE. WE SHOW THAT CHRONIC ALCOHOL TREATMENT DECREASES H4 HISTONE ACETYLATION AND HISTONE ACETYLTRANSFERASES ACTIVITY IN FRONTAL CORTEX, STRIATUM AND HIPPOCAMPUS OF WT MICE. ALTERATIONS IN CHROMATIN STRUCTURE WERE NOT OBSERVED IN TLR4(-/-) MICE. THESE RESULTS PROVIDE THE FIRST EVIDENCE OF THE ROLE THAT TLR4 FUNCTIONS PLAY IN THE BEHAVIORAL CONSEQUENCES OF ALCOHOL-INDUCED INFLAMMATORY DAMAGE AND SUGGEST THAT THE EPIGENETIC MODIFICATIONS MEDIATED BY TLR4 COULD CONTRIBUTE TO SHORT- OR LONG-TERM ALCOHOL-INDUCED BEHAVIORAL OR COGNITIVE DYSFUNCTIONS. 2011 11 4401 48 MODULATION OF NEURONAL PLASTICITY FOLLOWING CHRONIC CONCOMITANT ADMINISTRATION OF THE NOVEL ANTIPSYCHOTIC LURASIDONE WITH THE MOOD STABILIZER VALPROIC ACID. RATIONALE: COMBINATORY THERAPY IS WIDELY USED IN PSYCHIATRY OWING TO THE POSSIBILITY THAT DRUGS WITH DIFFERENT MECHANISMS OF ACTION MAY SYNERGIZE TO IMPROVE FUNCTIONS DETERIORATED IN SCHIZOPHRENIA, BIPOLAR DISORDERS, AND MAJOR DEPRESSION. WHILE COMBINATORY STRATEGIES RELY ON RECEPTOR AND SYNAPTIC MECHANISMS, IT SHOULD ALSO BE CONSIDERED THAT TWO DRUGS MAY ALSO "INTERACT" ON THE LONG-TERM TO DETERMINE MORE ROBUST CHANGES IN NEURONAL PLASTICITY, WHICH REPRESENTS A DOWNSTREAM TARGET IMPORTANT FOR FUNCTIONAL RECOVERY. OBJECTIVE: THE AIM OF THE STUDY IS TO INVESTIGATE NEUROADAPTIVE CHANGES SET IN MOTION BY CHRONIC CONCOMITANT ADMINISTRATION OF THE NOVEL ANTIPSYCHOTIC LURASIDONE AND THE MOOD STABILIZER VALPROATE. METHODS: ANIMALS WERE CHRONICALLY TREATED WITH LURASIDONE, VALPROATE, OR THE COMBINATION OF THE TWO DRUGS AND KILLED 24 H AFTER THE LAST INJECTION TO EVALUATE ALTERATIONS OF DIFFERENT MEASURES OF NEURONAL PLASTICITY SUCH AS THE NEUROTROPHIN BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF), THE IMMEDIATE EARLY GENE ACTIVITY-REGULATED CYTOSKELETAL ASSOCIATED PROTEIN, AND THE EPIGENETIC REGULATORS HDAC 1, 2, AND 5 IN DORSAL AND VENTRAL HIPPOCAMPUS. RESULTS: THE RESULTS SUGGEST THAT COADMINISTRATION OF LURASIDONE AND VALPROATE PRODUCES, WHEN COMPARED TO THE SINGLE DRUGS, A LARGER INCREASE IN THE EXPRESSION OF BDNF IN THE VENTRAL HIPPOCAMPUS, THROUGH THE REGULATION OF SPECIFIC NEUROTROPHIN TRANSCRIPTS. WE ALSO FOUND THAT THE HISTONE DEACETYLASES WERE REGULATED BY THE DRUG COMBINATION, SUGGESTING THAT SOME OF THE TRANSCRIPTIONAL CHANGES MAY BE SUSTAINED BY EPIGENETIC MECHANISMS. CONCLUSIONS: OUR RESULTS SUGGEST THAT THE BENEFICIAL EFFECTS ASSOCIATED WITH COMBINATORY TREATMENT BETWEEN A SECOND-GENERATION ANTIPSYCHOTIC AND A MOOD STABILIZER COULD RESULT FROM THE ABILITY TO MODULATE NEUROPLASTIC MOLECULES, WHOSE EXPRESSION AND FUNCTION IS DETERIORATED IN DIFFERENT PSYCHIATRIC CONDITIONS. 2013 12 4173 37 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 6207 39 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 14 5007 40 PERIPHERAL NERVE INJURY IS ASSOCIATED WITH CHRONIC, REVERSIBLE CHANGES IN GLOBAL DNA METHYLATION IN THE MOUSE PREFRONTAL CORTEX. CHANGES IN BRAIN STRUCTURE AND CORTICAL FUNCTION ARE ASSOCIATED WITH MANY CHRONIC PAIN CONDITIONS INCLUDING LOW BACK PAIN AND FIBROMYALGIA. THE MAGNITUDE OF THESE CHANGES CORRELATES WITH THE DURATION AND/OR THE INTENSITY OF CHRONIC PAIN. MOST STUDIES REPORT CHANGES IN COMMON AREAS INVOLVED IN PAIN MODULATION, INCLUDING THE PREFRONTAL CORTEX (PFC), AND PAIN-RELATED PATHOLOGICAL CHANGES IN THE PFC CAN BE REVERSED WITH EFFECTIVE TREATMENT. WHILE THE MECHANISMS UNDERLYING THESE CHANGES ARE UNKNOWN, THEY MUST BE DYNAMICALLY REGULATED. EPIGENETIC MODULATION OF GENE EXPRESSION IN RESPONSE TO EXPERIENCE AND ENVIRONMENT IS REVERSIBLE AND DYNAMIC. EPIGENETIC MODULATION BY DNA METHYLATION IS ASSOCIATED WITH ABNORMAL BEHAVIOR AND PATHOLOGICAL GENE EXPRESSION IN THE CENTRAL NERVOUS SYSTEM. DNA METHYLATION MIGHT ALSO BE INVOLVED IN MEDIATING THE PATHOLOGIES ASSOCIATED WITH CHRONIC PAIN IN THE BRAIN. WE THEREFORE TESTED A) WHETHER ALTERATIONS IN DNA METHYLATION ARE FOUND IN THE BRAIN LONG AFTER CHRONIC NEUROPATHIC PAIN IS INDUCED IN THE PERIPHERY USING THE SPARED NERVE INJURY MODAL AND B) WHETHER THESE INJURY-ASSOCIATED CHANGES ARE REVERSIBLE BY INTERVENTIONS THAT REVERSE THE PATHOLOGIES ASSOCIATED WITH CHRONIC PAIN. SIX MONTHS FOLLOWING PERIPHERAL NERVE INJURY, ABNORMAL SENSORY THRESHOLDS AND INCREASED ANXIETY WERE ACCOMPANIED BY DECREASED GLOBAL METHYLATION IN THE PFC AND THE AMYGDALA BUT NOT IN THE VISUAL CORTEX OR THE THALAMUS. ENVIRONMENTAL ENRICHMENT ATTENUATED NERVE INJURY-INDUCED HYPERSENSITIVITY AND REVERSED THE CHANGES IN GLOBAL PFC METHYLATION. FURTHERMORE, GLOBAL PFC METHYLATION CORRELATED WITH MECHANICAL AND THERMAL SENSITIVITY IN NEUROPATHIC MICE. IN SUMMARY, INDUCTION OF CHRONIC PAIN BY PERIPHERAL NERVE INJURY IS ASSOCIATED WITH EPIGENETIC CHANGES IN THE BRAIN. THESE CHANGES ARE DETECTED LONG AFTER THE ORIGINAL INJURY, AT A LONG DISTANCE FROM THE SITE OF INJURY AND ARE REVERSIBLE WITH ENVIRONMENTAL MANIPULATION. CHANGES IN BRAIN STRUCTURE AND CORTICAL FUNCTION THAT ARE ASSOCIATED WITH CHRONIC PAIN CONDITIONS MAY THEREFORE BE MEDIATED BY EPIGENETIC MECHANISMS. 2013 15 3952 33 LOCUS-SPECIFIC EPIGENETIC REMODELING CONTROLS ADDICTION- AND DEPRESSION-RELATED BEHAVIORS. CHRONIC EXPOSURE TO DRUGS OF ABUSE OR STRESS REGULATES TRANSCRIPTION FACTORS, CHROMATIN-MODIFYING ENZYMES AND HISTONE POST-TRANSLATIONAL MODIFICATIONS IN DISCRETE BRAIN REGIONS. GIVEN THE PROMISCUITY OF THE ENZYMES INVOLVED, IT HAS NOT YET BEEN POSSIBLE TO OBTAIN DIRECT CAUSAL EVIDENCE TO IMPLICATE THE REGULATION OF TRANSCRIPTION AND CONSEQUENT BEHAVIORAL PLASTICITY BY CHROMATIN REMODELING THAT OCCURS AT A SINGLE GENE. WE INVESTIGATED THE MECHANISM LINKING CHROMATIN DYNAMICS TO NEUROBIOLOGICAL PHENOMENA BY APPLYING ENGINEERED TRANSCRIPTION FACTORS TO SELECTIVELY MODIFY CHROMATIN AT A SPECIFIC MOUSE GENE IN VIVO. WE FOUND THAT HISTONE METHYLATION OR ACETYLATION AT THE FOSB LOCUS IN NUCLEUS ACCUMBENS, A BRAIN REWARD REGION, WAS SUFFICIENT TO CONTROL DRUG- AND STRESS-EVOKED TRANSCRIPTIONAL AND BEHAVIORAL RESPONSES VIA INTERACTIONS WITH THE ENDOGENOUS TRANSCRIPTIONAL MACHINERY. THIS APPROACH ALLOWED US TO RELATE THE EPIGENETIC LANDSCAPE AT A GIVEN GENE DIRECTLY TO REGULATION OF ITS EXPRESSION AND TO ITS SUBSEQUENT EFFECTS ON REWARD BEHAVIOR. 2014 16 1614 41 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 17 2670 48 ETHANOL ACTIONS ON THE VENTRAL TEGMENTAL AREA: NOVEL POTENTIAL TARGETS ON REWARD PATHWAY NEURONS. THE VENTRAL TEGMENTAL AREA (VTA) EVALUATES SALIENCE OF ENVIRONMENTAL STIMULI AND PROVIDES DOPAMINERGIC INNERVATION TO MANY BRAIN AREAS AFFECTED BY ACUTE AND CHRONIC ETHANOL EXPOSURE. WHILE PRIMARILY ASSOCIATED WITH REWARDING AND REINFORCING STIMULI, RECENT EVIDENCE INDICATES A ROLE FOR THE VTA IN AVERSION AS WELL. ETHANOL ACTIONS IN THE VTA MAY TRIGGER NEUROADAPTATION RESULTING IN REDUCTION OF THE AVERSIVE RESPONSES TO ALCOHOL AND A RELATIVE INCREASE IN THE REWARDING RESPONSES. IN SEARCHING FOR EFFECTIVE PHARMACOTHERAPIES FOR THE TREATMENT OF ALCOHOL ABUSE AND ALCOHOLISM, RECOGNITION OF THIS IMBALANCE MAY REVEAL NOVEL STRATEGIES. IN ADDITION TO CONVENTIONAL RECEPTOR/ION CHANNEL PHARMACOTHERAPIES, EPIGENETIC FACTORS THAT CONTROL NEUROADAPTATION TO CHRONIC ETHANOL TREATMENT CAN BE TARGETED AS AN AVENUE FOR DEVELOPMENT OF THERAPEUTIC APPROACHES TO RESTORE THE BALANCE. FURTHERMORE, WHEN EXPLORING THERAPIES TO ADDRESS REWARD/AVERSION IMBALANCE IN THE ACTION OF ALCOHOL IN THE VTA, SEX DIFFERENCES HAVE TO BE TAKEN INTO ACCOUNT TO ENSURE EFFECTIVE TREATMENT FOR BOTH MEN AND WOMEN. THESE PRINCIPLES APPLY TO A VTA-CENTRIC APPROACH TO THERAPIES, BUT SHOULD HOLD TRUE WHEN THINKING ABOUT THE OVERALL APPROACH IN THE DEVELOPMENT OF NEUROACTIVE DRUGS TO TREAT ALCOHOL USE DISORDERS. ALTHOUGH THE FUNCTIONS OF THE VTA ITSELF ARE COMPLEX, IT IS A USEFUL MODEL SYSTEM TO EVALUATE THE REWARD/AVERSION IMBALANCE THAT OCCURS WITH ETHANOL EXPOSURE AND COULD BE USED TO PROVIDE NEW LEADS IN THE EFFORTS TO DEVELOP NOVEL DRUGS TO TREAT ALCOHOLISM. 2018 18 4643 44 NEUROPATHIC PAIN AS A TRIGGER FOR HISTONE MODIFICATIONS IN LIMBIC CIRCUITRY. CHRONIC PAIN INVOLVES BOTH CENTRAL AND PERIPHERAL NEURONAL PLASTICITY THAT ENCOMPASSES CHANGES IN THE BRAIN, SPINAL CORD, AND PERIPHERAL NOCICEPTORS. WITHIN THE FOREBRAIN, MESOCORTICOLIMBIC REGIONS ASSOCIATED WITH EMOTIONAL REGULATION HAVE RECENTLY BEEN SHOWN TO EXHIBIT LASTING GENE EXPRESSION CHANGES IN MODELS OF CHRONIC PAIN. TO BETTER UNDERSTAND HOW SUCH ENDURING TRANSCRIPTIONAL CHANGES MIGHT BE REGULATED WITHIN BRAIN STRUCTURES ASSOCIATED WITH PROCESSING OF PAIN OR AFFECT, WE EXAMINED EPIGENETIC MODIFICATIONS INVOLVED WITH ACTIVE OR PERMISSIVE TRANSCRIPTIONAL STATES (HISTONE H3 LYSINE 4 MONO AND TRIMETHYLATION, AND HISTONE H3 LYSINE 27 ACETYLATION) IN PERIAQUEDUCTAL GRAY (PAG), LATERAL HYPOTHALAMUS (LH), NUCLEUS ACCUMBENS (NAC), AND VENTRAL TEGMENTAL AREA (VTA) 5 WEEKS AFTER SCIATIC NERVE INJURY IN MICE TO MODEL CHRONIC PAIN. FOR BOTH MALE AND FEMALE MICE IN CHRONIC PAIN, WE OBSERVED AN OVERALL TREND FOR A REDUCTION OF THESE EPIGENETIC MARKERS IN PERIAQUEDUCTAL GRAY, LH, AND NAC, BUT NOT VTA. MOREOVER, WE DISCOVERED THAT SOME EPIGENETIC MODIFICATIONS EXHIBITED CHANGES ASSOCIATED WITH PAIN HISTORY, WHILE OTHERS WERE ASSOCIATED WITH INDIVIDUAL DIFFERENCES IN PAIN SENSITIVITY. WHEN TAKEN TOGETHER, THESE RESULTS SUGGEST THAT NERVE INJURY LEADS TO CHRONIC CHROMATIN-MEDIATED SUPPRESSION OF TRANSCRIPTION IN KEY LIMBIC BRAIN STRUCTURES AND CIRCUITS, WHICH MAY UNDERLIE ENDURING CHANGES IN PAIN PROCESSING AND SENSITIVITY WITHIN THESE SYSTEMS. 2023 19 3086 43 GENOME-WIDE TRANSCRIPTOMICS OF THE AMYGDALA REVEALS SIMILAR OLIGODENDROCYTE-RELATED RESPONSES TO ACUTE AND CHRONIC ALCOHOL DRINKING IN FEMALE MICE. REPEATED EXCESSIVE ALCOHOL CONSUMPTION IS A RISK FACTOR FOR ALCOHOL USE DISORDER (AUD). ALTHOUGH AUD HAS BEEN MORE COMMON IN MEN THAN WOMEN, WOMEN DEVELOP MORE SEVERE BEHAVIORAL AND PHYSICAL IMPAIRMENTS. HOWEVER, RELATIVELY FEW NEW THERAPEUTICS TARGETING DEVELOPMENT OF AUD, PARTICULARLY IN WOMEN, HAVE BEEN VALIDATED. TO GAIN A BETTER UNDERSTANDING OF MOLECULAR MECHANISMS UNDERLYING ALCOHOL INTAKE, WE CONDUCTED A GENOME-WIDE RNA-SEQUENCING ANALYSIS IN FEMALE MICE EXPOSED TO DIFFERENT MODES (ACUTE VS CHRONIC) OF ETHANOL DRINKING. WE FOCUSED ON TRANSCRIPTIONAL PROFILES IN THE AMYGDALA INCLUDING THE CENTRAL AND BASOLATERAL SUBNUCLEI, BRAIN AREAS PREVIOUSLY IMPLICATED IN ALCOHOL DRINKING AND SEEKING. SURPRISINGLY, WE FOUND THAT BOTH DRINKING MODES TRIGGERED SIMILAR CHANGES IN GENE EXPRESSION AND CANONICAL PATHWAYS, INCLUDING UPREGULATION OF RIBOSOME-RELATED/TRANSLATIONAL PATHWAYS AND MYELINATION PATHWAYS, AND DOWNREGULATION OF CHROMATIN BINDING AND HISTONE MODIFICATION. IN ADDITION, ANALYSES OF HUB GENES AND UPSTREAM REGULATORY PATHWAYS REVEALED THAT VOLUNTARY ETHANOL CONSUMPTION AFFECTS EPIGENETIC CHANGES VIA HISTONE DEACETYLATION PATHWAYS, OLIGODENDROCYTE AND MYELIN FUNCTION, AND THE OLIGODENDROCYTE-RELATED TRANSCRIPTION FACTOR, SOX17. FURTHERMORE, A VIRAL VECTOR-ASSISTED KNOCKDOWN OF SOX17 GENE EXPRESSION IN THE AMYGDALA PREVENTED A GRADUAL INCREASE IN ALCOHOL CONSUMPTION DURING REPEATED ACCESSES. OVERALL, THESE RESULTS SUGGEST THAT THE EXPRESSION OF OLIGODENDROCYTE-RELATED GENES IN THE AMYGDALA IS SENSITIVE TO VOLUNTARY ALCOHOL DRINKING IN FEMALE MICE. THESE FINDINGS SUGGEST POTENTIAL MOLECULAR TARGETS FOR FUTURE THERAPEUTIC APPROACHES TO PREVENT THE DEVELOPMENT OF AUD, DUE TO REPEATED EXCESSIVE ALCOHOL CONSUMPTION, PARTICULARLY IN WOMEN. 2022 20 3341 35 HISTONE DEACETYLASE-2 IS INVOLVED IN STRESS-INDUCED COGNITIVE IMPAIRMENT VIA HISTONE DEACETYLATION AND PI3K/AKT SIGNALING PATHWAY MODIFICATION. EXPOSURE TO CHRONIC STRESS UPREGULATES BLOOD GLUCOCORTICOID LEVELS AND IMPAIRS COGNITION VIA DIVERSE EPIGENETIC MECHANISMS, SUCH AS HISTONE DEACETYLATION. HISTONE DEACETYLATION CAN LEAD TO TRANSCRIPTIONAL SILENCING OF MANY PROTEINS INVOLVED IN COGNITION AND MAY ALSO CAUSE LEARNING AND MEMORY DYSFUNCTION. HISTONE DEACETYLASE?2 (HDAC2) HAS BEEN DEMONSTRATED TO EPIGENETICALLY BLOCK COGNITION VIA A REDUCTION IN THE HISTONE ACETYLATION LEVEL; HOWEVER, IT IS UNKNOWN WHETHER HDAC2 IS INVOLVED IN THE COGNITIVE DECLINE INDUCED BY CHRONIC STRESS. TO THE BEST OF AUTHORS' KNOWLEDGE, THIS IS THE FIRST STUDY TO DEMONSTRATE THAT THE STRESS HORMONE CORTICOSTEROID UPREGULATE HDAC2 PROTEIN LEVELS IN NEURO?2A CELLS AND CAUSE CELL INJURIES. HDAC2 KNOCKDOWN RESULTED IN A SIGNIFICANT AMELIORATION OF THE PATHOLOGICAL CHANGES IN N2A CELLS VIA THE UPREGULATION OF HISTONE ACETYLATION AND MODIFICATIONS IN THE PHOSPHOINOSITIDE 3?KINASE/PROTEIN KINASE B SIGNALING PATHWAY. IN ADDITION, THE HDAC2 PROTEIN LEVELS WERE UPREGULATED IN 12?MONTH?OLD FEMALE C57BL/6J MICE UNDER CHRONIC STRESS IN VIVO. TAKEN TOGETHER, THESE FINDINGS SUGGESTED THAT HDAC2 MAY BE AN IMPORTANT NEGATIVE REGULATOR INVOLVED IN CHRONIC STRESS?INDUCED COGNITIVE IMPAIRMENT. 2017