1 6352 115 THE ROLE OF GABA(A) RECEPTORS IN THE DEVELOPMENT OF ALCOHOLISM. ALCOHOLISM IS A COMMON, HERITABLE, CHRONIC RELAPSING DISORDER. GABA(A) RECEPTORS UNDERGO ALLOSTERIC MODULATION BY ETHANOL, ANESTHETICS, BENZODIAZEPINES AND NEUROSTEROIDS AND HAVE BEEN IMPLICATED IN THE ACUTE AS WELL AS THE CHRONIC EFFECTS OF ETHANOL INCLUDING TOLERANCE, DEPENDENCE AND WITHDRAWAL. MEDICATIONS TARGETING GABA(A) RECEPTORS AMELIORATE THE SYMPTOMS OF ACUTE WITHDRAWAL. ETHANOL INDUCES PLASTICITY IN GABA(A) RECEPTORS: TOLERANCE IS ASSOCIATED WITH GENERALLY DECREASED GABA(A) RECEPTOR ACTIVATION AND DIFFERENTIALLY ALTERED SUBUNIT EXPRESSION. THE DOPAMINE (DA) MESOLIMBIC REWARD PATHWAY ORIGINATING IN THE VENTRAL TEGMENTAL AREA (VTA), AND INTERACTING STRESS CIRCUITRY PLAY AN IMPORTANT ROLE IN THE DEVELOPMENT OF ADDICTION. VTA GABAERGIC INTERNEURONS ARE THE PRIMARY INHIBITORY REGULATORS OF DA NEURONS AND A SUBSET OF VTA GABA(A) RECEPTORS MAY BE IMPLICATED IN THE SWITCH FROM HEAVY DRINKING TO DEPENDENCE. GABA(A) RECEPTORS MODULATE ANXIETY AND RESPONSE TO STRESS; IMPORTANT ELEMENTS OF SUSTAINED DRINKING AND RELAPSE. THE GABA(A) RECEPTOR SUBUNIT GENES CLUSTERED ON CHROMOSOME 4 ARE HIGHLY EXPRESSED IN THE REWARD PATHWAY. SEVERAL RECENT STUDIES HAVE PROVIDED STRONG EVIDENCE THAT ONE OF THESE GENES, GABRA2, IS IMPLICATED IN ALCOHOLISM IN HUMANS. THE INFLUENCE OF THE INTERACTION BETWEEN ETHANOL AND GABA(A) RECEPTORS IN THE REWARD PATHWAY ON THE DEVELOPMENT OF ALCOHOLISM TOGETHER WITH GENETIC AND EPIGENETIC VULNERABILITIES WILL BE EXPLORED IN THIS REVIEW. 2008 2 2670 41 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 3 2013 42 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 4 4150 45 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 5 4654 46 NEUROSTEROIDS (ALLOPREGNANOLONE) AND ALCOHOL USE DISORDER: FROM MECHANISMS TO POTENTIAL PHARMACOTHERAPY. ALCOHOL USE DISORDER (AUD) IS A MULTIFACETED RELAPSING DISORDER THAT IS COMMONLY COMORBID WITH PSYCHIATRIC DISORDERS, INCLUDING ANXIETY. ALCOHOL EXPOSURE PRODUCES A PLETHORA OF EFFECTS ON NEUROBIOLOGY. CURRENTLY, THERAPEUTIC STRATEGIES ARE LIMITED, AND ONLY A FEW TREATMENTS - DISULFIRAM, ACAMPROSATE, AND NALTREXONE - ARE AVAILABLE. GIVEN THE COMPLEXITY OF THIS DISORDER, THERE IS A GREAT NEED FOR THE IDENTIFICATION OF NOVEL TARGETS TO DEVELOP NEW PHARMACOTHERAPY. THE GABAERGIC SYSTEM, THE PRIMARY INHIBITORY SYSTEM IN THE BRAIN, IS ONE OF THE WELL-KNOWN TARGETS FOR ALCOHOL AND IS RESPONSIBLE FOR THE ANXIOLYTIC EFFECTS OF ALCOHOL. INTERESTINGLY, GABAERGIC NEUROTRANSMISSION IS FINE-TUNED BY NEUROACTIVE STEROIDS THAT EXERT A REGULATORY ROLE ON SEVERAL ENDOCRINE SYSTEMS INVOLVED IN NEUROPSYCHIATRIC DISORDERS INCLUDING AUD. MOUNTING EVIDENCE INDICATES THAT ALCOHOL ALTERS THE BIOSYNTHESIS OF NEUROSTEROIDS, WHEREAS ACUTE ALCOHOL INCREASES AND CHRONIC ALCOHOL DECREASES ALLOPREGNANOLONE LEVELS. OUR RECENT WORK HIGHLIGHTED THAT CHRONIC ALCOHOL-INDUCED CHANGES IN NEUROSTEROID LEVELS ARE MEDIATED BY EPIGENETIC MODIFICATIONS, E.G., DNA METHYLATION, AFFECTING KEY ENZYMES INVOLVED IN NEUROSTEROID BIOSYNTHESIS. THESE CHANGES WERE ASSOCIATED WITH CHANGES IN GABA(A) RECEPTOR SUBUNIT EXPRESSION, SUGGESTING AN IMBALANCE BETWEEN EXCITATORY AND INHIBITORY SIGNALING IN AUD. THIS REVIEW WILL RECAPITULATE THE ROLE OF NEUROSTEROIDS IN THE REGULATION OF THE NEUROENDOCRINE SYSTEM, HIGHLIGHT THEIR ROLE IN THE OBSERVED ALLOSTATIC LOAD IN AUD, AND DEVELOP A FRAMEWORK FROM MECHANISMS TO POTENTIAL PHARMACOTHERAPY. 2022 6 4653 32 NEUROSCIENCE OF ALCOHOLISM: MOLECULAR AND CELLULAR MECHANISMS. ALCOHOL USE AND ABUSE APPEAR TO BE RELATED TO NEUROADAPTIVE CHANGES AT FUNCTIONAL, NEUROCHEMICAL, AND STRUCTURAL LEVELS. ACUTE AND CHRONIC ETHANOL EXPOSURE HAVE BEEN SHOWN TO MODULATE FUNCTION OF THE ACTIVITY-DEPENDENT GENE TRANSCRIPTION FACTOR, CAMP-RESPONSIVE ELEMENT BINDING (CREB) PROTEIN IN THE BRAIN, WHICH MAY BE ASSOCIATED WITH THE DEVELOPMENT OF ALCOHOLISM. STUDY OF THE DOWNSTREAM EFFECTORS OF CREB HAVE IDENTIFIED SEVERAL IMPORTANT CREB-RELATED GENES, SUCH AS NEUROPEPTIDE Y, BRAIN-DERIVED NEUROTROPHIC FACTOR, ACTIVITY-REGULATED CYTOSKELETON-ASSOCIATED PROTEIN, AND CORTICOTROPHIN-RELEASING FACTOR, THAT MAY PLAY A CRUCIAL ROLE IN THE BEHAVIORAL EFFECTS OF ETHANOL AND MOLECULAR CHANGES IN THE SPECIFIC NEUROCIRCUITRY THAT UNDERLIE BOTH ALCOHOL ADDICTION AND A GENETIC PREDISPOSITION TO ALCOHOLISM. BRAIN CHROMATIN REMODELING DUE TO HISTONE COVALENT MODIFICATIONS MAY ALSO BE INVOLVED IN MEDIATING THE BEHAVIORAL EFFECTS AND NEUROADAPTIVE CHANGES THAT OCCUR DURING ETHANOL EXPOSURE. THIS REVIEW OUTLINES PROGRESSIVE NEUROSCIENCE RESEARCH INTO MOLECULAR AND EPIGENETIC MECHANISMS OF ALCOHOLISM. 2010 7 2058 27 EPIGENETIC CONTROL OF GENE EXPRESSION IN THE ALCOHOLIC BRAIN. CHRONIC ALCOHOL EXPOSURE CAUSES WIDESPREAD CHANGES IN BRAIN GENE EXPRESSION IN HUMANS AND ANIMAL MODELS. MANY OF THESE CONTRIBUTE TO CELLULAR ADAPTATIONS THAT ULTIMATELY LEAD TO BEHAVIORAL TOLERANCE AND ALCOHOL DEPENDENCE. THERE IS AN EMERGING APPRECIATION FOR THE ROLE OF EPIGENETIC PROCESSES IN ALCOHOL-INDUCED CHANGES IN BRAIN GENE EXPRESSION AND BEHAVIOR. FOR EXAMPLE, CHRONIC ALCOHOL EXPOSURE PRODUCES CHANGES IN DNA AND HISTONE METHYLATION, HISTONE ACETYLATION, AND MICRORNA EXPRESSION THAT AFFECT EXPRESSION OF MULTIPLE GENES IN VARIOUS TYPES OF BRAIN CELLS (I.E., NEURONS AND GLIA) AND CONTRIBUTE TO BRAIN PATHOLOGY AND BRAIN PLASTICITY ASSOCIATED WITH ALCOHOL ABUSE AND DEPENDENCE. DRUGS TARGETING THE EPIGENETIC "MASTER REGULATORS" ARE EMERGING AS POTENTIAL THERAPEUTICS FOR NEURODEGENERATIVE DISORDERS AND DRUG ADDICTION. 2013 8 6801 51 [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 9 584 41 BEHAVIORAL NEUROADAPTATION TO ALCOHOL: FROM GLUCOCORTICOIDS TO HISTONE ACETYLATION. A PRIME MECHANISM THAT CONTRIBUTES TO THE DEVELOPMENT AND MAINTENANCE OF ALCOHOLISM IS THE DYSREGULATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS ACTIVITY AND THE RELEASE OF GLUCOCORTICOIDS (CORTISOL IN HUMANS AND PRIMATES, CORTICOSTERONE IN RODENTS) FROM THE ADRENAL GLANDS. IN THE BRAIN, SUSTAINED, LOCAL ELEVATION OF GLUCOCORTICOID CONCENTRATION EVEN LONG AFTER CESSATION OF CHRONIC ALCOHOL CONSUMPTION COMPROMISES FUNCTIONAL INTEGRITY OF A CIRCUIT, INCLUDING THE PREFRONTAL CORTEX (PFC), THE HIPPOCAMPUS (HPC), AND THE AMYGDALA (AMG). THESE STRUCTURES ARE IMPLICATED IN LEARNING AND MEMORY PROCESSES AS WELL AS IN ORCHESTRATING NEUROADAPTIVE RESPONSES TO STRESS AND ANXIETY RESPONSES. THUS, POTENTIATION OF ANXIETY-RELATED NEUROADAPTATION BY ALCOHOL IS CHARACTERIZED BY AN ABNORMALLY AMG HYPERACTIVITY COUPLED WITH A HYPOFUNCTION OF THE PFC AND THE HPC. THIS REVIEW DESCRIBES RESEARCH ON MOLECULAR AND EPIGENETIC MECHANISMS BY WHICH ALCOHOL CAUSES DISTINCT REGION-SPECIFIC ADAPTIVE CHANGES IN GENE EXPRESSION PATTERNS AND ULTIMATELY LEADS TO A VARIETY OF COGNITIVE AND BEHAVIORAL IMPAIRMENTS ON PREFRONTAL- AND HIPPOCAMPAL-BASED TASKS. ALCOHOL-INDUCED NEUROADAPTATIONS INVOLVE THE DYSREGULATION OF NUMEROUS SIGNALING CASCADES, LEADING TO LONG-TERM CHANGES IN TRANSCRIPTIONAL PROFILES OF GENES, THROUGH THE ACTIONS OF TRANSCRIPTION FACTORS SUCH AS [CAMP RESPONSE ELEMENT-BINDING PROTEIN (CREB)] AND CHROMATIN REMODELING DUE TO POSTTRANSLATIONAL MODIFICATIONS OF HISTONE PROTEINS. WE DESCRIBE THE ROLE OF PREFRONTAL-HPC-AMG CIRCUIT IN MEDIATING THE EFFECTS OF ACUTE AND CHRONIC ALCOHOL ON LEARNING AND MEMORY, AND REGION-SPECIFIC MOLECULAR AND EPIGENETIC MECHANISMS INVOLVED IN THIS PROCESS. THIS REVIEW FIRST DISCUSSES THE IMPORTANCE OF BRAIN REGION-SPECIFIC DYSREGULATION OF GLUCOCORTICOID CONCENTRATION IN THE DEVELOPMENT OF ALCOHOL DEPENDENCE AND DESCRIBES HOW PERSISTENTLY INCREASED GLUCOCORTICOID LEVELS IN PFC MAY BE INVOLVED IN MEDIATING WORKING MEMORY IMPAIRMENTS AND NEUROADAPTIVE CHANGES DURING WITHDRAWAL FROM CHRONIC ALCOHOL INTAKE. IT THEN HIGHLIGHTS THE ROLE OF CAMP-PKA-CREB SIGNALING CASCADE AND HISTONE ACETYLATION WITHIN THE PFC AND LIMBIC STRUCTURES IN ALCOHOL-INDUCED ANXIETY AND BEHAVIORAL IMPAIRMENTS, AND HOW AN UNDERSTANDING OF FUNCTIONAL ALTERATIONS OF THESE PATHWAYS MIGHT LEAD TO BETTER TREATMENTS FOR NEUROPSYCHIATRIC DISORDERS. 2016 10 6174 45 THE HIPPOCAMPUS, NEUROTROPHIC FACTORS AND DEPRESSION: POSSIBLE IMPLICATIONS FOR THE PHARMACOTHERAPY OF DEPRESSION. DEPRESSION IS A PREVALENT, HIGHLY DEBILITATING MENTAL DISORDER AFFECTING UP TO 15% OF THE POPULATION AT LEAST ONCE IN THEIR LIFETIME, WITH HUGE COSTS FOR SOCIETY. NEUROBIOLOGICAL MECHANISMS OF DEPRESSION ARE STILL NOT WELL KNOWN, ALTHOUGH THERE IS CONSENSUS ABOUT INTERPLAY BETWEEN GENETIC AND ENVIRONMENTAL FACTORS. ANTIDEPRESSANT MEDICATIONS ARE FREQUENTLY USED IN DEPRESSION, BUT AT LEAST 50% OF PATIENTS ARE POOR RESPONDERS, EVEN TO MORE RECENTLY DISCOVERED MEDICATIONS. FURTHERMORE, CLINICAL RESPONSE ONLY OCCURS FOLLOWING WEEKS TO MONTHS OF TREATMENT AND ONLY CHRONIC TREATMENT IS EFFECTIVE, SUGGESTING THAT ACTIONS BEYOND THE RAPIDLY OCCURRING EFFECT OF ENHANCING MONOAMINERGIC SYSTEMS, SUCH AS ADAPTATION OF THESE SYSTEMS, ARE RESPONSIBLE FOR THE EFFECTS OF ANTIDEPRESSANTS. RECENT STUDIES INDICATE THAT AN IMPAIRMENT OF SYNAPTIC PLASTICITY (NEUROGENESIS, AXON BRANCHING, DENDRITOGENESIS AND SYNAPTOGENESIS) IN SPECIFIC AREAS OF THE CNS, PARTICULARLY THE HIPPOCAMPUS, MAY BE A CORE FACTOR IN THE PATHOPHYSIOLOGY OF DEPRESSION. THE ABNORMAL NEURAL PLASTICITY MAY BE RELATED TO ALTERATIONS IN THE LEVELS OF NEUROTROPHIC FACTORS, NAMELY BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF), WHICH PLAY A CENTRAL ROLE IN PLASTICITY. AS BDNF IS REPRESSED BY STRESS, EPIGENETIC REGULATION OF THE BDNF GENE MAY PLAY AN IMPORTANT ROLE IN DEPRESSION. THE HIPPOCAMPUS IS SMALLER IN DEPRESSED PATIENTS, ALTHOUGH IT IS UNCLEAR WHETHER SMALLER SIZE IS A CONSEQUENCE OF DEPRESSION OR A PRE-EXISTING, VULNERABILITY MARKER FOR DEPRESSION. ENVIRONMENTAL STRESSORS TRIGGERING ACTIVATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS CAUSE THE BRAIN TO BE EXPOSED TO CORTICOSTEROIDS, AFFECTING NEUROBEHAVIOURAL FUNCTIONS WITH A STRONG DOWNREGULATION OF HIPPOCAMPAL NEUROGENESIS, AND ARE A MAJOR RISK FACTOR FOR DEPRESSION. ANTIDEPRESSANT TREATMENT INCREASES BDNF LEVELS, STIMULATES NEUROGENESIS AND REVERSES THE INHIBITORY EFFECTS OF STRESS, BUT THIS EFFECT IS EVIDENT ONLY AFTER 3-4 WEEKS OF ADMINISTRATION, THE TIME COURSE FOR MATURATION OF NEW NEURONS. THE ABLATION OF HIPPOCAMPAL NEUROGENESIS BLOCKS THE BEHAVIOURAL EFFECTS OF ANTIDEPRESSANTS IN ANIMAL MODELS. THE ABOVE FINDINGS SUGGEST NEW POSSIBLE TARGETS FOR THE PHARMACOTHERAPY OF DEPRESSION SUCH AS NEUROTROPHIC FACTORS, THEIR RECEPTORS AND RELATED INTRACELLULAR SIGNALLING CASCADES; AGENTS COUNTERACTING THE EFFECTS OF STRESS ON HIPPOCAMPAL NEUROGENESIS (INCLUDING ANTAGONISTS OF CORTICOSTEROIDS, INFLAMMATORY CYTOKINES AND THEIR RECEPTORS); AND AGENTS FACILITATING THE ACTIVATION OF GENE EXPRESSION AND INCREASING THE TRANSCRIPTION OF NEUROTROPHINS IN THE BRAIN. 2011 11 5444 37 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 12 1870 37 EMERGING ROLE OF EPIGENETIC MECHANISMS IN ALCOHOL ADDICTION. ALCOHOL USE DISORDER (AUD) IS A COMPLEX BRAIN DISORDER WITH AN ARRAY OF PERSISTENT BEHAVIORAL AND NEUROCHEMICAL MANIFESTATIONS. BOTH GENETIC AND ENVIRONMENTAL FACTORS ARE KNOWN TO CONTRIBUTE TO THE DEVELOPMENT OF AUD, AND RECENT STUDIES ON ALCOHOL EXPOSURE AND SUBSEQUENT CHANGES IN GENE EXPRESSION SUGGEST THE IMPORTANCE OF EPIGENETIC MECHANISMS. IN PARTICULAR, HISTONE MODIFICATIONS AND DNA METHYLATION HAVE EMERGED AS IMPORTANT REGULATORS OF GENE EXPRESSION AND ASSOCIATED PHENOTYPES OF AUD. GIVEN THE THERAPEUTIC POTENTIAL OF EPIGENETIC TARGETS, THIS REVIEW AIMS TO SUMMARIZE THE ROLE OF EPIGENETIC REGULATION IN OUR CURRENT UNDERSTANDING OF AUD BY EVALUATING KNOWN EPIGENETIC SIGNATURES OF BRAIN REGIONS CRITICAL TO ADDICTIVE BEHAVIORS IN BOTH ANIMAL AND HUMAN STUDIES THROUGHOUT VARIOUS STAGES OF AUD. MORE SPECIFICALLY, THE EFFECTS OF ACUTE AND CHRONIC ALCOHOL EXPOSURE, TOLERANCE, AND POSTEXPOSURE WITHDRAWAL ON EPIGENETICALLY INDUCED CHANGES TO GENE EXPRESSION AND SYNAPTIC PLASTICITY WITHIN KEY BRAIN REGIONS AND THE ASSOCIATED BEHAVIORAL PHENOTYPES HAVE BEEN DISCUSSED. UNDERSTANDING THE CONTRIBUTION OF EPIGENETIC REGULATION TO CRUCIAL SIGNALING PATHWAYS MAY PROVE VITAL FOR FUTURE DEVELOPMENT OF NOVEL BIOMARKERS AND TREATMENT AGENTS IN AMELIORATING OR PREVENTING AUD. 2017 13 5624 31 SELECTIVE BOOSTING OF TRANSCRIPTIONAL AND BEHAVIORAL RESPONSES TO DRUGS OF ABUSE BY HISTONE DEACETYLASE INHIBITION. HISTONE ACETYLATION AND OTHER MODIFICATIONS OF THE CHROMATIN ARE IMPORTANT REGULATORS OF GENE EXPRESSION AND, CONSEQUENTLY, MAY CONTRIBUTE TO DRUG-INDUCED BEHAVIORS AND NEUROPLASTICITY. EARLIER STUDIES HAVE SHOWN THAT A REDUCTION IN HISTONE DEACETYLASE (HDAC) ACTIVITY RESULTS IN THE ENHANCEMENT OF SOME PSYCHOSTIMULANT-INDUCED BEHAVIORS. IN THIS STUDY, WE EXTEND THOSE SEMINAL FINDINGS BY SHOWING THAT THE ADMINISTRATION OF THE HDAC INHIBITOR SODIUM BUTYRATE ENHANCES MORPHINE-INDUCED LOCOMOTOR SENSITIZATION AND CONDITIONED PLACE PREFERENCE. IN CONTRAST, THIS COMPOUND HAS NO EFFECTS ON THE DEVELOPMENT OF MORPHINE TOLERANCE AND DEPENDENCE. SIMILAR EFFECTS WERE OBSERVED FOR COCAINE AND ETHANOL-INDUCED BEHAVIORS. THESE BEHAVIORAL CHANGES WERE ACCOMPANIED BY A SELECTIVE BOOSTING OF A COMPONENT OF THE TRANSCRIPTIONAL PROGRAM ACTIVATED BY CHRONIC MORPHINE ADMINISTRATION THAT INCLUDED CIRCADIAN CLOCK GENES AND OTHER GENES RELEVANT TO ADDICTIVE BEHAVIOR. OUR RESULTS SUPPORT A SPECIFIC FUNCTION FOR HISTONE ACETYLATION AND THE EPIGENETIC MODULATION OF TRANSCRIPTION AT A REDUCED NUMBER OF BIOLOGICALLY RELEVANT LOCI ON NON-HOMEOSTATIC, LONG-LASTING, DRUG-INDUCED BEHAVIORAL PLASTICITY. 2009 14 4327 43 MICRORNAS MODULATE INTERACTIONS BETWEEN STRESS AND RISK FOR COCAINE ADDICTION. EXPOSURE TO STRESS INCREASES VULNERABILITY TO DRUG ABUSE, AS WELL AS RELAPSE LIABILITY IN ADDICTED INDIVIDUALS. CHRONIC DRUG USE ALTERS STRESS RESPONSE IN A MANNER THAT INCREASES DRUG SEEKING BEHAVIORS AND RELAPSE. DRUG EXPOSURE AND WITHDRAWAL HAVE BEEN SHOWN TO ALTER STRESS RESPONSES, AND CORTICOSTEROID MEDIATORS OF STRESS HAVE BEEN SHOWN TO IMPACT ADDICTION-RELATED BRAIN FUNCTION AND DRUG-SEEKING BEHAVIOR. DESPITE THE DOCUMENTED INTERPLAY BETWEEN STRESS AND SUBSTANCE ABUSE, THE MECHANISMS BY WHICH STRESS EXPOSURE AND DRUG SEEKING INTERACT REMAIN LARGELY UNKNOWN. RECENT STUDIES INDICATE THAT MICRORNAS (MIRNA) PLAY A SIGNIFICANT ROLE IN STRESS MODULATION AS WELL AS ADDICTION-RELATED PROCESSES INCLUDING NEUROGENESIS, SYNAPSE DEVELOPMENT, PLASTICITY, DRUG ACQUISITION, WITHDRAWAL AND RELAPSE. MIRNAS ARE SHORT NON-CODING RNAS THAT FUNCTION AS BIDIRECTIONAL EPIGENETIC MODULATORS OF GENE EXPRESSION THROUGH IMPERFECT SEQUENCE TARGETED DEGRADATION AND/OR TRANSLATIONAL REPRESSION OF MRNAS. THEY SERVE AS DYNAMIC REGULATORS OF CNS PHYSIOLOGY AND PATHOPHYSIOLOGY, AND FACILITATE RAPID AND LONG-LASTING CHANGES TO COMPLEX SYSTEMS AND BEHAVIORS. MIRNAS FUNCTION IN GLUCOCORTICOID SIGNALING AND THE MESOLIMBIC DOPAMINE REWARD SYSTEM, AS WELL AS MOOD DISORDERS RELATED TO DRUG WITHDRAWAL. THE LITERATURE SUGGESTS MIRNAS PLAY A PIVOTAL ROLE IN THE INTERACTION BETWEEN EXPOSURES TO STRESS, ADDICTION-RELATED PROCESSES, AND NEGATIVE AFFECTIVE STATES RESULTING FROM EXTENDED DRUG WITHDRAWAL. THIS MANUSCRIPT REVIEWS RECENT EVIDENCE FOR THE ROLE OF MIRNAS IN THE MODULATION OF STRESS AND COCAINE RESPONSES, AND DISCUSSES POTENTIAL MEDIATION OF THE INTERACTION OF THESE SYSTEMS BY MIRNAS. UNCOVERING THE MECHANISM BEHIND THE ASSOCIATION OF STRESS AND DRUG TAKING HAS THE POTENTIAL TO IMPACT THE TREATMENT OF DRUG ABUSE AND PREVENTION OF RELAPSE. FURTHER COMPREHENSION OF THESE COMPLEX INTERACTIONS MAY PROVIDE PROMISING NEW TARGETS FOR THE TREATMENT OF DRUG ADDICTION. 2016 15 3587 36 IMPACT OF TLR4 ON BEHAVIORAL AND COGNITIVE DYSFUNCTIONS ASSOCIATED WITH ALCOHOL-INDUCED NEUROINFLAMMATORY DAMAGE. TOLL-LIKE RECEPTORS (TLRS) PLAY AN IMPORTANT ROLE IN THE INNATE IMMUNE RESPONSE, AND EMERGING EVIDENCE INDICATES THEIR ROLE IN BRAIN INJURY AND NEURODEGENERATION. OUR RECENT RESULTS HAVE DEMONSTRATED THAT ETHANOL IS CAPABLE OF ACTIVATING GLIAL TLR4 RECEPTORS AND THAT THE ELIMINATION OF THESE RECEPTORS IN MICE PROTECTS AGAINST ETHANOL-INDUCED GLIAL ACTIVATION, INDUCTION OF INFLAMMATORY MEDIATORS AND APOPTOSIS. THIS STUDY WAS DESIGNED TO ASSESS WHETHER ETHANOL-INDUCED INFLAMMATORY DAMAGE CAUSES BEHAVIORAL AND COGNITIVE CONSEQUENCES, AND IF BEHAVIORAL ALTERATIONS ARE DEPENDENT OF TLR4 FUNCTIONS. HERE WE SHOW IN MICE DRINKING ALCOHOL FOR 5MONTHS, FOLLOWED BY A 15-DAY WITHDRAWAL PERIOD, THAT ACTIVATION OF THE ASTROGLIAL AND MICROGLIAL CELLS IN FRONTAL CORTEX AND STRIATUM IS MAINTAINED AND THAT THESE EVENTS ARE ASSOCIATED WITH COGNITIVE AND ANXIETY-RELATED BEHAVIORAL IMPAIRMENTS IN WILD-TYPE (WT) MICE, AS DEMONSTRATED BY TESTING THE ANIMALS WITH OBJECT MEMORY RECOGNITION, CONDITIONED TASTE AVERSION AND DARK AND LIGHT BOX ANXIETY TASKS. MICE LACKING TLR4 RECEPTORS ARE PROTECTED AGAINST ETHANOL-INDUCED INFLAMMATORY DAMAGE, AND BEHAVIORAL ASSOCIATED EFFECTS. WE FURTHER ASSESS THE POSSIBILITY OF THE EPIGENETIC MODIFICATIONS PARTICIPATING IN SHORT- OR LONG-TERM BEHAVIORAL EFFECTS ASSOCIATED WITH NEUROINFLAMMATORY DAMAGE. WE SHOW THAT CHRONIC ALCOHOL TREATMENT DECREASES H4 HISTONE ACETYLATION AND HISTONE ACETYLTRANSFERASES ACTIVITY IN FRONTAL CORTEX, STRIATUM AND HIPPOCAMPUS OF WT MICE. ALTERATIONS IN CHROMATIN STRUCTURE WERE NOT OBSERVED IN TLR4(-/-) MICE. THESE RESULTS PROVIDE THE FIRST EVIDENCE OF THE ROLE THAT TLR4 FUNCTIONS PLAY IN THE BEHAVIORAL CONSEQUENCES OF ALCOHOL-INDUCED INFLAMMATORY DAMAGE AND SUGGEST THAT THE EPIGENETIC MODIFICATIONS MEDIATED BY TLR4 COULD CONTRIBUTE TO SHORT- OR LONG-TERM ALCOHOL-INDUCED BEHAVIORAL OR COGNITIVE DYSFUNCTIONS. 2011 16 6527 36 TRANSCRIPTIONAL CONTROL OF MALADAPTIVE AND PROTECTIVE RESPONSES IN ALCOHOLICS: A ROLE OF THE NF-KAPPAB SYSTEM. ALCOHOL DEPENDENCE AND ASSOCIATED COGNITIVE IMPAIRMENT APPEAR TO RESULT FROM MALADAPTIVE NEUROPLASTICITY IN RESPONSE TO CHRONIC ALCOHOL CONSUMPTION, NEUROINFLAMMATION AND NEURODEGENERATION. THE INHERENT STABILITY OF BEHAVIORAL ALTERATIONS ASSOCIATED WITH THE ADDICTED STATE SUGGESTS THAT TRANSCRIPTIONAL AND EPIGENETIC MECHANISMS ARE OPERATIVE. NF-KAPPAB TRANSCRIPTION FACTORS ARE REGULATORS OF SYNAPTIC PLASTICITY AND INFLAMMATION, AND RESPONSIVE TO A VARIETY OF STIMULI INCLUDING ALCOHOL. THESE FACTORS ARE ABUNDANT IN THE BRAIN WHERE THEY HAVE DIVERSE FUNCTIONS THAT DEPEND ON THE COMPOSITION OF THE NF-KAPPAB COMPLEX AND CELLULAR CONTEXT. IN NEURON CELL BODIES, NF-KAPPAB IS CONSTITUTIVELY ACTIVE, AND INVOLVED IN NEURONAL INJURY AND NEUROPROTECTION. HOWEVER, AT THE SYNAPSE, NF-KAPPAB IS PRESENT IN A LATENT FORM AND UPON ACTIVATION IS TRANSPORTED TO THE CELL NUCLEUS. IN GLIA, NF-KAPPAB IS INDUCIBLE AND REGULATES INFLAMMATORY PROCESSES THAT EXACERBATE ALCOHOL-INDUCED NEURODEGENERATION. ANIMAL STUDIES DEMONSTRATE THAT ACUTE ALCOHOL EXPOSURE TRANSIENTLY ACTIVATES NF-KAPPAB, WHICH INDUCES NEUROINFLAMMATORY RESPONSES AND NEURODEGENERATION. POSTMORTEM STUDIES OF BRAINS OF HUMAN ALCOHOLICS SUGGEST THAT REPEATED CYCLES OF ALCOHOL CONSUMPTION AND WITHDRAWAL CAUSE ADAPTIVE CHANGES IN THE NF-KAPPAB SYSTEM THAT MAY PERMIT THE SYSTEM TO BETTER TOLERATE EXCESSIVE STIMULATION. THIS TYPE OF TOLERANCE, ENSURING A LOW DEGREE OF RESPONSIVENESS TO APPLIED STIMULI, APPARENTLY DIFFERS FROM THAT IN THE IMMUNE SYSTEM, AND MAY REPRESENT A COMPENSATORY RESPONSE THAT PROTECTS BRAIN CELLS AGAINST ALCOHOL NEUROTOXICITY. THIS VIEW IS SUPPORTED BY FINDINGS SHOWING PREFERENTIAL DOWNREGULATION OF PRO-APOPTOTIC GENE EXPRESSION IN THE AFFECTED BRAIN AREAS IN HUMAN ALCOHOLICS. ALTHOUGH FURTHER VERIFICATION IS NEEDED, WE SPECULATE THAT NF-KAPPAB-DRIVEN NEUROINFLAMMATION AND DISRUPTION TO NEUROPLASTICITY PLAY A SIGNIFICANT ROLE IN REGULATING ALCOHOL DEPENDENCE AND COGNITIVE IMPAIRMENT. 2011 17 2513 23 EPIGENETICS AND PSYCHOSTIMULANT ADDICTION. CHRONIC DRUG EXPOSURE ALTERS GENE EXPRESSION IN THE BRAIN AND PRODUCES LONG-TERM CHANGES IN NEURAL NETWORKS THAT UNDERLIE COMPULSIVE DRUG TAKING AND SEEKING. EXACTLY HOW DRUG-INDUCED CHANGES IN SYNAPTIC PLASTICITY AND SUBSEQUENT GENE EXPRESSION ARE TRANSLATED INTO PERSISTENT NEUROADAPTATIONS REMAINS UNCLEAR. EMERGING EVIDENCE SUGGESTS THAT COMPLEX DRUG-INDUCED NEUROADAPTATIONS IN THE BRAIN ARE MEDIATED BY HIGHLY SYNCHRONIZED AND DYNAMIC PATTERNS OF GENE REGULATION. RECENTLY, IT HAS BECOME CLEAR THAT EPIGENETIC MECHANISMS CONTRIBUTE TO DRUG-INDUCED STRUCTURAL, SYNAPTIC, AND BEHAVIORAL PLASTICITY BY REGULATING EXPRESSION OF GENE NETWORKS. HERE WE REVIEW HOW ALTERATIONS IN HISTONE MODIFICATIONS, DNA METHYLATION, AND MICRORNAS REGULATE GENE EXPRESSION AND CONTRIBUTE TO PSYCHOSTIMULANT ADDICTION WITH A FOCUS ON THE EPIGENETIC MECHANISMS THAT REGULATE BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) EXPRESSION FOLLOWING CHRONIC COCAINE EXPOSURE. IDENTIFYING EPIGENETIC SIGNATURES THAT DEFINE PSYCHOSTIMULANT ADDICTION MAY LEAD TO NOVEL, EFFICACIOUS TREATMENTS FOR DRUG CRAVING AND RELAPSE. 2013 18 6775 33 [ALCOHOL DEPENDENCE MEDIATED BY MONOAMINE NEUROTRANSMITTERS IN THE CENTRAL NERVOUS SYSTEM]. ALCOHOL DEPENDENCE, A CHRONIC RELAPSING BRAIN DISEASE WITH THE CHARACTERISTICS OF DRINKING ALCOHOL OUT OF CONTROL, HAS BECOME A SERIOUS SOCIAL PROBLEM. MONOAMINE NEUROTRANSMITTERS, MAINLY INCLUDING DOPAMINE AND 5-HYDROXYTRYP NOTTAMINE, PLAY IMPORTANT ROLES IN THE OCCURRENCE, DEVELOPMENT AND NEURAL DYSFUNCTION OF ALCOHOL DEPENDENCE SYNDROME. IN THIS REVIEW, THE ROLES OF KEY FACTORS OF THE MONOAMINE SYSTEM (DOPAMINE RECEPTOR GENES, 5-HYDROXYTRYPTAMINE RECEPTOR GENES, TRANSPORTER GENES, TYROSINE HYDROXYLASE GENE, TRYPTOPHANHYDROXYLASE GENE AND MONOAMINE OXIDASE GENE) IN ALCOHOL DEPENDENCE WERE DISCUSSED, AND STRATEGIES FOR FURTHER STUDIES OF MOLECULAR MECHANISMS WERE PROPOSED BASED ON GENE KNOCKOUT MICE MODELS GENERATED IN OUR LABORATORY. THEN, COMBINING WITH STUDIES ON TYROSINE HYDROXYLASE ACTIVATOR CAMKII IN OUR LAB, THERAPEUTIC TARGETS WERE DISCUSSED. BESIDES, EPIGENETIC STRATEGIES FOR PREVENTION AND TREATMENT OF ALCOHOL DEPENDENCE SYNDROME WERE PROPOSED. FURTHERMORE, MANIPULATING METHYLATION LEVELS IN GENE REGULATORY REGIONS AND ALTERNATIVE SPLICING OF PRE-MRNAS MIGHT ALSO HAVE CLINICAL IMPLICATIONS. FINALLY, BASED ON NEW FINDINGS ON GENETIC POLYMORPHISM, IT IS OF GREAT POTENTIAL TO CARRY OUT INDIVIDUAL PREVENTION AND TREATMENT FOR PATIENTS SUFFERING FROM ALCOHOL DEPENDENCE. 2014 19 2606 37 EPIGENETICS-BEYOND THE GENOME IN ALCOHOLISM. GENETIC AND ENVIRONMENTAL FACTORS PLAY A ROLE IN THE DEVELOPMENT OF ALCOHOLISM. WHOLE-GENOME EXPRESSION PROFILING HAS HIGHLIGHTED THE IMPORTANCE OF SEVERAL GENES THAT MAY CONTRIBUTE TO ALCOHOL ABUSE DISORDERS. IN ADDITION, MORE RECENT FINDINGS HAVE ADDED YET ANOTHER LAYER OF COMPLEXITY TO THE OVERALL MOLECULAR MECHANISMS INVOLVED IN A PREDISPOSITION TO ALCOHOLISM AND ADDICTION BY DEMONSTRATING THAT PROCESSES RELATED TO GENETIC FACTORS THAT DO NOT MANIFEST AS DNA SEQUENCE CHANGES (I.E., EPIGENETIC PROCESSES) PLAY A ROLE. BOTH ACUTE AND CHRONIC ETHANOL EXPOSURE CAN ALTER GENE EXPRESSION LEVELS IN SPECIFIC NEURONAL CIRCUITS THAT GOVERN THE BEHAVIORAL CONSEQUENCES RELATED TO TOLERANCE AND DEPENDENCE. THE UNREMITTING CYCLE OF ALCOHOL CONSUMPTION OFTEN INCLUDES SATIATION AND SELF-MEDICATION WITH ALCOHOL, FOLLOWED BY EXCRUCIATING WITHDRAWAL SYMPTOMS AND THE RESULTANT RELAPSE, WHICH REFLECTS BOTH THE POSITIVE AND NEGATIVE AFFECTIVE STATES OF ALCOHOL ADDICTION. RECENT STUDIES HAVE INDICATED THAT BEHAVIORAL CHANGES INDUCED BY ACUTE AND CHRONIC ETHANOL EXPOSURE MAY INVOLVE CHROMATIN REMODELING RESULTING FROM COVALENT HISTONE MODIFICATIONS AND DNA METHYLATION IN THE NEURONAL CIRCUITS INVOLVING A BRAIN REGION CALLED THE AMYGDALA. THESE FINDINGS HAVE HELPED IDENTIFY ENZYMES INVOLVED IN EPIGENETIC MECHANISMS, SUCH AS THE HISTONE DEACETYLASE, HISTONE ACETYLTRANSFERASE, AND DNA METHYLTRANSFERASE ENZYMES, AS NOVEL THERAPEUTIC TARGETS FOR THE DEVELOPMENT OF FUTURE PHARMACOTHERAPIES FOR THE TREATMENT OF ALCOHOLISM. 2012 20 4643 29 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