1 3970 109 LONG-LASTING EPIGENETIC CHANGES IN THE DOPAMINE TRANSPORTER IN ADULT ANIMALS EXPOSED TO AMPHETAMINE DURING EMBRYOGENESIS: INVESTIGATING BEHAVIORAL EFFECTS. THE DOPAMINE TRANSPORTER (DAT) IS AN INTEGRAL MEMBER OF THE DOPAMINERGIC SYSTEM AND IS RESPONSIBLE FOR THE RELEASE AND REUPTAKE OF DOPAMINE FROM THE SYNAPTIC SPACE INTO THE DOPAMINERGIC NEURONS. DAT IS ALSO THE MAJOR TARGET OF AMPHETAMINE (AMPH). THE EFFECTS OF AMPH ON DAT HAVE BEEN INTENSIVELY STUDIED; HOWEVER, THE MECHANISMS UNDERLYING THE LONG-TERM EFFECTS CAUSED BY EMBRYONAL EXPOSURE TO ADDICTIVE DOSES OF AMPH REMAIN LARGELY UNEXPLORED. AS IN MAMMALS, IN THE NEMATODE C. ELEGANS AMPH CAUSES CHANGES IN LOCOMOTION WHICH ARE LARGELY MEDIATED BY THE C. ELEGANS DAT HOMOLOGUE, DAT-1. HERE, WE SHOW THAT CHRONIC EMBRYONIC EXPOSURES TO AMPH ALTER THE EXPRESSION OF DAT-1 IN ADULT C. ELEGANS VIA LONG-LASTING EPIGENETIC MODIFICATIONS. THESE CHANGES ARE CORRELATED WITH AN ENHANCED BEHAVIORAL RESPONSE TO AMPH IN ADULT ANIMALS. IMPORTANTLY, PHARMACOLOGICAL AND GENETIC INTERVENTION DIRECTED AT PREVENTING THE AMPH-INDUCED EPIGENETIC MODIFICATIONS OCCURRING DURING EMBRYOGENESIS INHIBITED THE LONG-LASTING BEHAVIORAL EFFECTS OBSERVED IN ADULT ANIMALS. BECAUSE MANY COMPONENTS OF THE DOPAMINERGIC SYSTEM, AS WELL AS EPIGENETIC MECHANISMS, ARE HIGHLY CONSERVED BETWEEN C. ELEGANS AND MAMMALS, THESE RESULTS COULD BE CRITICAL FOR OUR UNDERSTANDING OF HOW DRUGS OF ABUSE INITIATE PREDISPOSITION TO ADDICTION. 2023 2 6125 30 THE EPIGENETIC MECHANISMS OF AMPHETAMINE. AMPHETAMINE (AMPH) IS A PSYCHOSTIMULANT AND THE MOST PRESCRIBED DRUG TO TREAT ATTENTION DEFICIT HYPERACTIVE DISORDER (ADHD). ALTHOUGH THERAPEUTICALLY USED DOSES ARE GENERALLY WELL TOLERATED, NUMEROUS SIDE EFFECTS ARE STILL KNOWN TO OCCUR, SUCH AS JITTERINESS, LOSS OF APPETITE AND PSYCHOSIS. MOREOVER, AMPH IS LIABLE TO BE ABUSED BY USERS LOOKING FOR INCREASED ALERTNESS, WEIGHT LOSS OR ATHLETIC PERFORMANCE. A GROWING BODY OF EVIDENCE INDICATES THAT DRUGS OF ABUSE, INCLUDING AMPH, CONTROL GENE EXPRESSION THROUGH CHROMATIN MODIFICATIONS. HOWEVER, WHILE NUMEROUS STUDIES HAVE INVESTIGATED THE MOLECULAR MECHANISMS OF AMPH ACTION, ONLY A SMALL NUMBER OF STUDIES HAVE EXPLORED CHANGES IN GENE EXPRESSION CAUSED BY AMPH. THIS REVIEW EXAMINES THE EPIGENETIC CHANGES INDUCED BY CHRONIC AND ACUTE TREATMENTS WITH AMPH AND INCLUDES, WHERE RELEVANT, DATA OBTAINED WITH OTHER PSYCHOSTIMULANTS SUCH AS METHAMPHETAMINE AND COCAINE. 2015 3 2235 29 EPIGENETIC MODIFICATIONS, ALCOHOLIC BRAIN AND POTENTIAL DRUG TARGETS. ACUTE AND CHRONIC ALCOHOL EXPOSURE EVIDENTLY INFLUENCES EPIGENETIC CHANGES, BOTH TRANSIENTLY AND PERMANENTLY, AND THESE CHANGES IN TURN INFLUENCE A VARIETY OF CELLS AND ORGAN SYSTEMS THROUGHOUT THE BODY. MANY OF THE ALCOHOL-INDUCED EPIGENETIC MODIFICATIONS CAN CONTRIBUTE TO CELLULAR ADAPTATIONS THAT ULTIMATELY LEAD TO BEHAVIORAL TOLERANCE AND ALCOHOL DEPENDENCE. THE PERSISTENCE OF BEHAVIORAL CHANGES DEMONSTRATES THAT LONG-LASTING CHANGES IN GENE EXPRESSION, WITHIN PARTICULAR REGIONS OF THE BRAIN, MAY CONTRIBUTE IMPORTANTLY TO THE ADDICTION PHENOTYPE. THE RESEARCH ACTIVITIES OVER THE PAST YEARS HAVE DEMONSTRATED A CRUCIAL ROLE OF EPIGENETIC MECHANISMS IN CAUSING LONG LASTING AND TRANSIENT CHANGES IN THE EXPRESSION OF SEVERAL GENES IN DIVERSE TISSUES, INCLUDING BRAIN. THIS HAS STIMULATED RECENT RESEARCH WORK THAT IS AIMED AT CHARACTERIZING THE INFLUENCE OF EPIGENETIC REGULATORY EVENTS IN MEDIATING THE LONG LASTING AND TRANSIENT EFFECTS OF ALCOHOL ABUSE ON THE BRAIN IN HUMANS AND ANIMAL MODELS OF ALCOHOL ADDICTION. IN THIS STUDY, WE UPDATE OUR CURRENT UNDERSTANDING OF THE IMPACT OF ALCOHOL EXPOSURE ON EPIGENETIC MECHANISMS IN THE BRAIN AND REFURBISH THE KNOWLEDGE OF EPIGENETICS IN THE DIRECTION OF NEW DRUGS DEVELOPMENT. 2016 4 2089 34 EPIGENETIC DYSREGULATION OF THE DOPAMINE SYSTEM IN DIET-INDUCED OBESITY. CHRONIC INTAKE OF HIGH-FAT (HF) DIET IS KNOWN TO ALTER BRAIN NEUROTRANSMITTER SYSTEMS THAT PARTICIPATE IN THE CENTRAL REGULATION OF FOOD INTAKE. DOPAMINE (DA) SYSTEM CHANGES IN RESPONSE TO HF DIET HAVE BEEN OBSERVED IN THE HYPOTHALAMUS, IMPORTANT IN THE HOMEOSTATIC CONTROL OF FOOD INTAKE, AS WELL AS WITHIN THE CENTRAL REWARD CIRCUITRY [VENTRAL TEGMENTAL AREA (VTA), NUCLEUS ACCUMBENS (NAC), AND PRE-FRONTAL CORTEX (PFC)], CRITICAL FOR CODING THE REWARDING PROPERTIES OF PALATABLE FOOD AND IMPORTANT IN HEDONICALLY DRIVEN FEEDING BEHAVIOR. USING A MOUSE MODEL OF DIET-INDUCED OBESITY (DIO), SIGNIFICANT ALTERATIONS IN THE EXPRESSION OF DA-RELATED GENES WERE DOCUMENTED IN ADULT ANIMALS, AND THE GENERAL PATTERN OF GENE EXPRESSION CHANGES WAS OPPOSITE WITHIN THE HYPOTHALAMUS VERSUS THE REWARD CIRCUITRY (INCREASED VS. DECREASED, RESPECTIVELY). DIFFERENTIAL DNA METHYLATION WAS IDENTIFIED WITHIN THE PROMOTER REGIONS OF TYROSINE HYDROXYLASE (TH) AND DOPAMINE TRANSPORTER (DAT), AND THE PATTERN OF THIS RESPONSE WAS CONSISTENT WITH THE PATTERN OF GENE EXPRESSION. BEHAVIORS CONSISTENT WITH INCREASED HYPOTHALAMIC DA AND DECREASED REWARD CIRCUITRY DA WERE OBSERVED. THESE DATA IDENTIFY DIFFERENTIAL DNA METHYLATION AS AN EPIGENETIC MECHANISM LINKING THE CHRONIC INTAKE OF HF DIET WITH ALTERED DA-RELATED GENE EXPRESSION, AND THIS RESPONSE VARIES BY BRAIN REGION AND DNA SEQUENCE. 2012 5 2292 28 EPIGENETIC REGULATION IN SUBSTANCE USE DISORDERS. SUBSTANCE USE DISORDER IS A CHRONIC CONDITION OF COMPULSIVE DRUG SEEKING AND USE THAT IS MEDIATED BY STABLE CHANGES IN CENTRAL REWARD PATHWAYS. REPEATED USE OF ABUSED DRUGS CAUSES PERSISTENT ALTERATIONS IN GENE EXPRESSION RESPONSIBLE FOR THE LONG-TERM BEHAVIORAL AND STRUCTURAL CHANGES. RECENTLY, IT HAS BEEN SUGGESTED THAT EPIGENETIC MECHANISMS ARE RESPONSIBLE IN PART FOR THESE DRUG-INDUCED CHANGES IN GENE EXPRESSION. ONE OF THE ALLURING ASPECTS OF EPIGENETIC REGULATION OF GENE EXPRESSION IS THAT EPIGENETIC MECHANISMS MAY PROVIDE TRANSIENT AND POTENTIALLY STABLE CONDITIONS THAT IN TURN MAY ULTIMATELY PARTICIPATE IN THE MOLECULAR MECHANISMS REQUIRED FOR NEURONAL CHANGES SUBSERVING LONG-LASTING CHANGES IN BEHAVIOR. THIS REVIEW DESCRIBES EPIGENETIC MECHANISMS OF GENE REGULATION AND THEN DISCUSSES THE EMERGING ROLE OF EPIGENETICS IN DRUG-INDUCED PLASTICITY AND BEHAVIOR. UNDERSTANDING THESE MECHANISMS THAT ESTABLISH AND MAINTAIN DRUG-DEPENDENT PLASTICITY CHANGES MAY LEAD TO DEEPER UNDERSTANDING OF SUBSTANCE USE DISORDERS AS WELL AS NOVEL APPROACHES TO TREATMENT. 2010 6 6097 14 THE EFFECTS OF STRESS ON GLUTAMATERGIC TRANSMISSION IN THE BRAIN. STRESS LEADS TO DETRIMENTAL EFFECTS ON BRAIN FUNCTIONS AND RESULTS IN VARIOUS DISEASES. RECENT STUDIES HIGHLIGHT THE INVOLVEMENT OF GLUTAMATERGIC TRANSMISSION IN PATHOGENESIS OF DEPRESSIVE BEHAVIORS AND FEARS. ACUTE STRESS GENERATES DIFFERENT IMPACTS ON THE EXCITATORY TRANSMISSION COMPARED TO CHRONIC STRESS. DIFFERENT NEUROMODULATORS AND EPIGENETIC FACTORS ALSO PARTICIPATE IN THE ALTERATION OF SYNAPTIC TRANSMISSION AND THE REGULATION OF SYNAPTIC PLASTICITY. RESTORATION OF THE GLUTAMATERGIC TRANSMISSION IN STRESS-AFFECTED BRAIN AREAS THEREFORE PROVIDES NOVEL DIRECTIONS OF THERAPEUTIC INTERVENTIONS AGAINST STRESS. 2015 7 6895 23 [SYSTEMIC CONTROL OF THE MOLECULAR, CELL, AND EPIGENETIC MECHANISMS OF LONG-LASTING CONSEQUENCES OF STRESS]. BASED ON M.E. LOBASHEV'S VIEWS OF THE SYSTEMIC CONTROL OF GENETIC AND CYTOGENEITC PROCESSES AND A SUBSTANTIAL EFFECT OF EXCITABILITY ON PLASTIC CHANGES IN THE CENTRAL NERVOUS SYSTEM (CNS), THE EFFECT OF PROLONGED EMOTIONAL AND PAIN STRESS (PEPS) ON THE MOLECULAR, CELL, AND EPIGENETIC MECHANISMS OF INJURY MEMORY WAS STUDIED IN RAT STRAINS BRED FOR A CERTAIN EXCITABILITY OF THE NERVOUS SYSTEM. PEPS WAS FOR THE FIRST TIME FOUND TO CAUSE LONG-LASTING (2 MONTHS) MORPHOLOGICAL ALTERATIONS OF THE CA3 REGION OF THE HIPPOCAMPUS AND TO MODIFY THE GENOME ACTIVITY OF ITS PYRAMIDAL NEURONS. THE TWO PHENOMENA WERE POTENTIATED BY A GENETICALLY DETERMINED LOW FUNCTIONAL STATE OF THE CNS. THE POST-STRESS REGULATION OF THE GENOME FUNCTION IN HIPPOCAMPAL NEURONS WAS MEDIATED BY CHANGES IN HETEROCHROMATIN CONFORMATION, ACTIVATION OF METHYL-CPG-BINDING PROTEIN (MECP2) SYNTHESIS, AND SUBSEQUENT CHANGES IN ACETYLATION OF HISTONE H4. GENETICALLY DETERMINED HIGH EXCITABILITY OF THE NERVOUS SYSTEM PROVED TO BE A RISK FACTOR THAT AFFECTS THE SPECIFICS AND TIME COURSE OF THE OBSERVED MOLECULAR, CELL, AND GENETIC TRANSFORMATIONS OF NEURONS. THE RESULTS PROVIDE FOR A BETTER UNDERSTANDING OF THE EPIGENETIC MECHANISMS OF INJURY MEMORY, WHICH FORMS A PATHOGENETIC BASIS FOR POSTTRAUMATIC STRESS DISORDER AND OTHER HUMAN PSYCHOGENIC CONDITIONS CHARACTERIZED BY A PROLONGED DURATION. 2009 8 584 36 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 9 2471 29 EPIGENETIC TRANSGENERATIONAL INHERITANCE OF ALTERED STRESS RESPONSES. ANCESTRAL ENVIRONMENTAL EXPOSURES HAVE PREVIOUSLY BEEN SHOWN TO PROMOTE EPIGENETIC TRANSGENERATIONAL INHERITANCE AND INFLUENCE ALL ASPECTS OF AN INDIVIDUAL'S LIFE HISTORY. IN ADDITION, PROXIMATE LIFE EVENTS SUCH AS CHRONIC STRESS HAVE DOCUMENTED EFFECTS ON THE DEVELOPMENT OF PHYSIOLOGICAL, NEURAL, AND BEHAVIORAL PHENOTYPES IN ADULTHOOD. WE USED A SYSTEMS BIOLOGY APPROACH TO INVESTIGATE IN MALE RATS THE INTERACTION OF THE ANCESTRAL MODIFICATIONS CARRIED TRANSGENERATIONALLY IN THE GERM LINE AND THE PROXIMATE MODIFICATIONS INVOLVING CHRONIC RESTRAINT STRESS DURING ADOLESCENCE. WE FIND THAT A SINGLE EXPOSURE TO A COMMON-USE FUNGICIDE (VINCLOZOLIN) THREE GENERATIONS REMOVED ALTERS THE PHYSIOLOGY, BEHAVIOR, METABOLIC ACTIVITY, AND TRANSCRIPTOME IN DISCRETE BRAIN NUCLEI IN DESCENDANT MALES, CAUSING THEM TO RESPOND DIFFERENTLY TO CHRONIC RESTRAINT STRESS. THIS ALTERATION OF BASELINE BRAIN DEVELOPMENT PROMOTES A CHANGE IN NEURAL GENOMIC ACTIVITY THAT CORRELATES WITH CHANGES IN PHYSIOLOGY AND BEHAVIOR, REVEALING THE INTERACTION OF GENETICS, ENVIRONMENT, AND EPIGENETIC TRANSGENERATIONAL INHERITANCE IN THE SHAPING OF THE ADULT PHENOTYPE. THIS IS AN IMPORTANT DEMONSTRATION IN AN ANIMAL THAT ANCESTRAL EXPOSURE TO AN ENVIRONMENTAL COMPOUND MODIFIES HOW DESCENDANTS OF THESE PROGENITOR INDIVIDUALS PERCEIVE AND RESPOND TO A STRESS CHALLENGE EXPERIENCED DURING THEIR OWN LIFE HISTORY. 2012 10 1981 30 EPIGENETIC ALTERATIONS IN DNA AND HISTONE MODIFICATIONS CAUSED BY DEPRESSION AND ANTIDEPRESSANT DRUGS: LESSONS FROM THE RODENT MODELS. EPIGENETIC MODIFICATIONS REGULATE CHROMATIN FOLDING AND FUNCTION. EPIGENETIC MECHANISMS REGULATE TRANSCRIPTION MEDIATING EFFECTS OF VARIOUS STIMULI ON GENE EXPRESSION. THESE MECHANISMS ARE INVOLVED IN TRANSCRIPTIONAL CONTROL IN VARIOUS PHYSIOLOGICAL AND PATHOLOGICAL CONDITIONS INCLUDING NEUROPSYCHIATRIC DISORDERS AND BEHAVIORAL ABNORMALITIES SUCH AS DEPRESSION. IN RODENTS, EXPOSURE TO CHRONIC SOCIAL STRESS WAS SHOWN TO INDUCE BEHAVIORAL IMPAIRMENTS AND MEMORY/LEARNING DEFICITS THAT RESEMBLE DEPRESSIVE-LIKE PHENOTYPE IN HUMANS. THE RODENT MODELS OF CHRONIC STRESS WERE WIDELY USED TO STUDY MOLECULAR MECHANISMS OF DEPRESSION. IN THESE MODELS, EARLY EXPOSURE TO CHRONIC STRESS SUCH AS PRENATAL OR POSTNATAL STRESS INDUCES LONG-TERM HYPERACTIVE STRESS RESPONSES, BEHAVIORAL ABNORMALITIES, AND FUNCTIONAL IMPAIRMENTS IN BRAIN FUNCTION THAT PERSIST IN ADULTHOOD. FURTHERMORE, THESE ALTERATIONS CAN BE TRANSMITTED TO OFFSPRING OF CHRONICALLY STRESSED ANIMALS ACROSS SEVERAL GENERATIONS. MOLECULAR STUDIES IN ANIMAL MODELS SHOWED THAT CHRONIC STRESS INDUCES STABLE EPIGENETIC CHANGES IN SPECIFIC BRAIN REGIONS, PRIMARILY IN THE LIMBIC SYSTEM. THESE CHANGES LEAD TO LONG-LASTING ABNORMALITIES IN BEHAVIOR THAT PERSIST IN ADULTHOOD AND CAN BE TRANSMITTED TO OFFSPRING. TREATMENT WITH EPIGENETICALLY ACTIVE ANTIDEPRESSANTS DISRUPTS THE ABNORMAL STRESS-INDUCED EPIGENETIC PROGRAMMING AND PROVIDES EPIGENETIC PATTERNS THAT RESEMBLE EPIGENETIC BACKGROUND OF STRESS RESILIENT INDIVIDUALS. 2017 11 1687 31 DRUGS OF ABUSE: EPIGENETIC MECHANISMS IN TOXICITY AND ADDICTION. THE ABUSE OF SUBSTANCES SUCH AS ETHANOL, COCAINE, AMPHETAMINES AND HEROIN IS ASSOCIATED WITH TOXIC EFFECTS ON ALMOST EVERY SYSTEM OF THE ORGANISM. FURTHERMORE, THE TRANSITION FROM OCCASIONAL-RECREATIONAL USE TO CHRONIC ABUSE AND ADDICTION IS A SERIOUS PSYCHIATRIC DISORDER WITH ONLY FEW CHANCES FOR EFFECTIVE AND DEFINITIVE TREATMENT SINCE MOST INDIVIDUALS RELAPSE, EVEN AFTER LONG PERIODS OF ABSTINENCE. IT IS THEREFORE OF UTMOST IMPORTANCE TO ELUCIDATE THE MECHANISMS BY WHICH THESE SUBSTANCES EXERT THEIR TOXICITY AND MEDIATE ADDICTION, IN ORDER TO DEVELOP NEW, EFFICIENT THERAPEUTIC STRATEGIES WITH A LONG-TERM OUTCOME, WHICH ARE CURRENTLY LACKING. WE ALREADY KNOW THAT IN A GREAT NUMBER OF THESE MECHANISMS, ALTERED GENE FUNCTION IS INVOLVED. BUT, WITH THE NEW FIELD OF EPIGENETICS, THERE IS INCREASING EVIDENCE THAT CHANGES IN THE EPIGENOME ARE RESPONSIBLE FOR THE ALTERED GENE FUNCTION. THE ADVANCES IN THE FIELD OF EPIGENETICS TOWARDS ELUCIDATION OF THE MECHANISMS UNDERLYING TOXICITY AND ADDICTION FOR ETHANOL, COCAINE, AMPHETAMINES AND HEROIN ARE CURRENTLY PRESENTED AND DISCUSSED IN THIS REVIEW. 2011 12 4653 30 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 13 5649 24 SEX DIFFERENCES IN PSYCHOSTIMULANT ABUSE: IMPLICATIONS FOR ESTROGEN RECEPTORS AND HISTONE DEACETYLASES. SUBSTANCE ABUSE IS A CHRONIC PATHOLOGICAL DISORDER THAT NEGATIVELY AFFECTS MANY HEALTH AND NEUROLOGICAL PROCESSES. A GROWING BODY OF LITERATURE HAS REVEALED GENDER DIFFERENCES IN SUBSTANCE USE. COMPARED TO MEN, WOMEN DISPLAY DISTINCT DRUG-USE PHENOTYPES ACCOMPANIED BY RECOVERY AND REHABILITATION DISPARITIES. THESE OBSERVATIONS HAVE LED TO THE NOTION THAT SEX-DEPENDENT SUSCEPTIBILITIES EXIST ALONG THE PROGRESSION TO ADDICTION. WITHIN THIS SCOPE, NEUROADAPTATIONS FOLLOWING PSYCHOSTIMULANT EXPOSURE ARE THOUGHT TO BE DISTINCT FOR EACH SEX. THIS REVIEW SUMMARIZES CLINICAL FINDINGS AND ANIMAL RESEARCH REPORTING SEX DIFFERENCES IN THE SUBJECTIVE AND BEHAVIORAL RESPONSES TO COCAINE, METHAMPHETAMINE, AND NICOTINE. THIS DISCUSSION IS FOLLOWED BY AN EXAMINATION OF EPIGENETIC AND MOLECULAR ALTERATIONS IMPLICATED IN THE ADDICTION PROCESS. SPECIAL CONSIDERATION IS GIVEN TO HISTONE DEACETYLASES AND ESTROGEN RECEPTOR-MEDIATED GENE EXPRESSION. 2022 14 1796 41 EFFECT OF GERM-FREE STATUS ON TRANSCRIPTIONAL PROFILES IN THE NUCLEUS ACCUMBENS AND TRANSCRIPTOMIC RESPONSE TO CHRONIC MORPHINE. OPIOID USE DISORDER IS A PUBLIC HEALTH CRISIS THAT CAUSES TREMENDOUS SUFFERING FOR PATIENTS AS WELL AS SUBSTANTIAL SOCIAL AND ECONOMIC COSTS FOR SOCIETY. THERE ARE CURRENTLY AVAILABLE TREATMENTS FOR PATIENTS WITH OPIOID USE DISORDER, BUT THEY REMAIN INTOLERABLE OR INEFFECTIVE FOR MANY. THUS THE NEED TO DEVELOP NEW AVENUES FOR THERAPEUTICS DEVELOPMENT IN THIS SPACE IS GREAT. SUBSTANTIAL WORK IN MODELS OF SUBSTANCE USE DISORDERS, INCLUDING OPIOID USE DISORDER, DEMONSTRATES THAT PROLONGED EXPOSURE TO DRUGS OF ABUSE LEADS TO MARKED TRANSCRIPTIONAL AND EPIGENETIC DYSREGULATION IN LIMBIC SUBSTRUCTURES. IT IS WIDELY BELIEVED THAT THESE CHANGES IN GENE REGULATION IN RESPONSE TO DRUGS ARE A KEY DRIVING FACTOR IN THE PERPETUATION OF DRUG TAKING AND SEEKING BEHAVIORS. THUS, DEVELOPMENT OF INTERVENTIONS THAT COULD SHAPE TRANSCRIPTIONAL REGULATION IN RESPONSE TO DRUGS OF ABUSE WOULD BE OF HIGH VALUE. OVER THE PAST DECADE THERE HAS BEEN A SURGE IN RESEARCH DEMONSTRATING THAT THE RESIDENT BACTERIA OF THE GASTROINTESTINAL TRACT, COLLECTIVELY THE GUT MICROBIOME, CAN HAVE TREMENDOUS INFLUENCE ON NEUROBIOLOGICAL AND BEHAVIORAL PLASTICITY. PREVIOUS WORK FROM OUR GROUP AND OTHERS HAS DEMONSTRATED THAT ALTERATIONS IN THE GUT MICROBIOME CAN ALTER BEHAVIORAL RESPONSES TO OPIOIDS IN MULTIPLE PARADIGMS. ADDITIONALLY, WE HAVE PREVIOUSLY REPORTED THAT DEPLETION OF THE GUT MICROBIOME WITH ANTIBIOTICS MARKEDLY SHIFTS THE TRANSCRIPTOME OF THE NUCLEUS ACCUMBENS FOLLOWING PROLONGED MORPHINE EXPOSURE. IN THIS MANUSCRIPT WE PRESENT A COMPREHENSIVE ANALYSIS OF THE EFFECTS OF THE GUT MICROBIOME ON TRANSCRIPTIONAL REGULATION OF THE NUCLEUS ACCUMBENS FOLLOWING MORPHINE BY UTILIZING GERM-FREE, ANTIBIOTIC TREATED, AND CONTROL MICE. THIS ALLOWS FOR DETAILED UNDERSTANDING OF THE ROLE OF THE MICROBIOME IN REGULATING BASELINE TRANSCRIPTOMIC CONTROL, AS WELL AS RESPONSE TO MORPHINE. WE FIND THAT GERM-FREE STATUS LEADS TO A MARKED GENE DYSREGULATION IN A MANNER DISTINCT TO ADULT MICE TREATED WITH ANTIBIOTICS, AND THAT ALTERED GENE PATHWAYS ARE HIGHLY RELATED TO CELLULAR METABOLIC PROCESSES. THESE DATA PROVIDE ADDITIONAL INSIGHT INTO THE ROLE OF THE GUT MICROBIOME IN MODULATING BRAIN FUNCTION AND LAY A FOUNDATION FOR FURTHER STUDY IN THIS AREA. 2023 15 2119 27 EPIGENETIC HISTONE MODIFICATION REGULATES DEVELOPMENTAL LEAD EXPOSURE INDUCED HYPERACTIVITY IN RATS. LEAD (PB) EXPOSURE WAS COMMONLY CONSIDERED AS A HIGH ENVIRONMENTAL RISK FACTOR FOR THE DEVELOPMENT OF ATTENTION-DEFICIT/HYPERACTIVITY DISORDER (ADHD). HOWEVER, THE MOLECULAR BASIS OF THIS PATHOLOGICAL PROCESS STILL REMAINS ELUSIVE. IN LIGHT OF THE ROLE OF EPIGENETICS IN MODULATING THE NEUROLOGICAL DISEASE AND THE CAUSATIVE ENVIRONMENT, THE ALTERATIONS OF HISTONE MODIFICATIONS IN THE HIPPOCAMPUS OF RATS EXPOSED BY VARIOUS DOSES OF LEAD, ALONG WITH CONCOMITANT BEHAVIORAL DEFICITS, WERE INVESTIGATED IN THIS STUDY. ACCORDING TO THE FREE AND FORCED OPEN FIELD TEST, THERE SHOWED THAT IN A DOSAGE-DEPENDENT MANNER, LEAD EXPOSURE COULD RESULT IN THE INCREASED LOCOMOTOR ACTIVITY OF RATS, THAT IS, HYPERACTIVITY: A SUBTYPE OF ADHD. WESTERN BLOTTING ASSAYS REVEALED THAT THE LEVELS OF HISTONE ACETYLATION INCREASED SIGNIFICANTLY IN THE HIPPOCAMPUS BY CHRONIC LEAD EXPOSURE, WHILE NO DRAMATIC CHANGES WERE DETECTED IN TERMS OF EXPRESSION YIELDS OF ADHD-RELATED DOPAMINERGIC PROTEINS, INDICATING THAT HISTONE ACETYLATION PLAYS ESSENTIAL ROLES IN THIS TOXICANT-INVOLVED PATHOGENESIS. IN ADDITION, THE INCREASED LEVEL OF HISTONE ACETYLATION MIGHT BE ATTRIBUTED TO THE ENZYMATIC ACTIVITY OF P300, A TYPICAL HISTONE ACETYLTRANSFERASE, AS THE TRANSCRIPTIONAL LEVEL OF P300 WAS SIGNIFICANTLY INCREASED UPON HIGHER-DOSE PB EXPOSURE. IN SUMMARY, THIS STUDY FIRST DISCOVERED THE EPIGENETIC MECHANISM BRIDGING THE ENVIRONMENTAL INFLUENCE (PB) AND THE DISEASE ITSELF (ADHD) IN THE HISTONE MODIFICATION LEVEL, PAVING THE WAY FOR THE COMPREHENSIVE UNDERSTANDING OF ADHD'S ETIOLOGY AND IN FURTHER STEPS, ESTABLISHING THE THERAPY STRATEGY OF THIS WIDESPREAD NEUROLOGICAL DISORDER. 2014 16 2913 28 GENE REGULATORY MECHANISMS UNDERLYING SEX DIFFERENCES IN BRAIN DEVELOPMENT AND PSYCHIATRIC DISEASE. THE SEXUAL DIFFERENTIATION OF THE MAMMALIAN NERVOUS SYSTEM REQUIRES THE PRECISE COORDINATION OF THE TEMPORAL AND SPATIAL REGULATION OF GENE EXPRESSION IN DIVERSE CELL TYPES. SEX HORMONES ACT AT MULTIPLE DEVELOPMENTAL TIME POINTS TO SPECIFY SEX-TYPICAL DIFFERENTIATION DURING EMBRYONIC AND EARLY DEVELOPMENT AND TO COORDINATE SUBSEQUENT RESPONSES TO GONADAL HORMONES LATER IN LIFE BY ESTABLISHING SEX-TYPICAL PATTERNS OF EPIGENETIC MODIFICATIONS ACROSS THE GENOME. THUS, MUTATIONS ASSOCIATED WITH NEUROPSYCHIATRIC CONDITIONS MAY RESULT IN SEXUALLY DIMORPHIC SYMPTOMS BY ACTING ON DIFFERENT NEURAL SUBSTRATES OR CHROMATIN LANDSCAPES IN MALES AND FEMALES. FINALLY, AS STRESS HORMONE SIGNALING MAY DIRECTLY ALTER THE MOLECULAR MACHINERY THAT INTERACTS WITH SEX HORMONE RECEPTORS TO REGULATE GENE EXPRESSION, THE CONTRIBUTION OF CHRONIC STRESS TO THE PATHOGENESIS OR PRESENTATION OF MENTAL ILLNESS MAY BE ADDITIONALLY DIFFERENT BETWEEN THE SEXES. HERE, WE REVIEW THE MECHANISMS THAT CONTRIBUTE TO SEXUAL DIFFERENTIATION IN THE MAMMALIAN NERVOUS SYSTEM AND CONSIDER SOME OF THE IMPLICATIONS OF THESE PROCESSES FOR SEX DIFFERENCES IN NEUROPSYCHIATRIC CONDITIONS. 2018 17 2058 25 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 18 3708 23 INFLUENCE OF PHARMACOLOGICAL AND EPIGENETIC FACTORS TO SUPPRESS NEUROTROPHIC FACTORS AND ENHANCE NEURAL PLASTICITY IN STRESS AND MOOD DISORDERS. STRESS-INDUCED MAJOR DEPRESSION AND MOOD DISORDERS ARE CHARACTERIZED BY BEHAVIOURAL ABNORMALITIES AND PSYCHIATRIC ILLNESS, LEADING TO DISABILITY AND IMMATURE MORTALITY WORLDWIDE. NEUROBIOLOGICAL MECHANISMS OF STRESS AND MOOD DISORDERS ARE DISCUSSED CONSIDERING RECENT FINDINGS, AND CHALLENGES TO ENHANCE PHARMACOLOGICAL EFFECTS OF ANTIDEPRESSANT, AND MOOD STABILIZERS. PHARMACOLOGICAL ENHANCEMENT OF KETAMINE AND SCOPOLAMINE REGULATES DEPRESSION AT THE MOLECULAR LEVEL, INCREASING SYNAPTIC PLASTICITY IN PREFRONTAL REGIONS. BLOOD-DERIVED NEUROTROPHIC FACTORS FACILITATE MOOD-DEFICIT SYMPTOMS. EPIGENETIC FACTORS MAINTAIN STRESS-RESILIENCE IN HIPPOCAMPAL REGION. REGULATION OF NEUROTROPHIC FACTORS BLOCKADES STRESS, AND ENHANCES NEURONAL SURVIVAL THOUGH IT PARALYZES LIMBIC REGIONS. MOLECULAR AGENTS AND NEUROTROPHIC FACTORS ALSO CONTROL BEHAVIORAL AND SYNAPTIC PLASTICITY IN ADDICTION AND STRESS DISORDERS. FUTURE RESEARCH ON NEURONAL DYNAMICS AND CELLULAR ACTIONS CAN BE DIRECTED TO OBTAIN THE ETIOLOGY OF SYNAPTIC DYSREGULATION IN MOOD DISORDER AND STRESS. FOR THE FIRST TIME, THE CURRENT REVIEW CONTRIBUTES TO THE LITERATURE OF SYNAPTIC PLASTICITY REPRESENTING THE ROLE OF EPIGENETIC MECHANISMS AND GLUCOCORTICOID RECEPTORS TO PREDICT DEPRESSION AND ANXIETY IN CLINICAL CONDITIONS. 2019 19 2598 26 EPIGENETICS OF THE DEPRESSED BRAIN: ROLE OF HISTONE ACETYLATION AND METHYLATION. MAJOR DEPRESSIVE DISORDER IS A CHRONIC, REMITTING SYNDROME INVOLVING WIDELY DISTRIBUTED CIRCUITS IN THE BRAIN. STABLE ALTERATIONS IN GENE EXPRESSION THAT CONTRIBUTE TO STRUCTURAL AND FUNCTIONAL CHANGES IN MULTIPLE BRAIN REGIONS ARE IMPLICATED IN THE HETEROGENEITY AND PATHOGENESIS OF THE ILLNESS. EPIGENETIC EVENTS THAT ALTER CHROMATIN STRUCTURE TO REGULATE PROGRAMS OF GENE EXPRESSION HAVE BEEN ASSOCIATED WITH DEPRESSION-RELATED BEHAVIOR, ANTIDEPRESSANT ACTION, AND RESISTANCE TO DEPRESSION OR 'RESILIENCE' IN ANIMAL MODELS, WITH INCREASING EVIDENCE FOR SIMILAR MECHANISMS OCCURRING IN POSTMORTEM BRAINS OF DEPRESSED HUMANS. IN THIS REVIEW, WE DISCUSS RECENT ADVANCES IN OUR UNDERSTANDING OF EPIGENETIC CONTRIBUTIONS TO DEPRESSION, IN PARTICULAR THE ROLE OF HISTONE ACETYLATION AND METHYLATION, WHICH ARE REVEALING NOVEL MECHANISTIC INSIGHT INTO THE SYNDROME THAT MAY AID IN THE DEVELOPMENT OF NOVEL TARGETS FOR DEPRESSION TREATMENT. 2013 20 636 41 BIOLOGICAL SUBSTRATES OF ADDICTION. THIS REVIEW IS AN INTRODUCTION TO ADDICTION, THE REWARD CIRCUITRY, AND LABORATORY ADDICTION MODELS. ADDICTION IS A CHRONIC DISEASE HALLMARKED BY A STATE OF COMPULSIVE DRUG SEEKING THAT PERSISTS DESPITE NEGATIVE CONSEQUENCES. MOST OF THE ADVANCES IN ADDICTION RESEARCH HAVE CENTERED ON THE CANONICAL AND CONTEMPORARY DRUGS OF ABUSE; HOWEVER, ADDICTIONS TO OTHER ACTIVITIES AND STIMULI ALSO EXIST. SUBSTANCES OF ABUSE HAVE THE POTENTIAL TO INDUCE LONG-LASTING CHANGES IN THE BRAIN AT THE BEHAVIORAL, CIRCUIT, AND SYNAPTIC LEVELS. ADDICTION-RELATED BEHAVIORAL CHANGES INVOLVE INITIATION, ESCALATION, AND OBSESSION TO DRUG SEEKING AND MUCH OF THE CURRENT RESEARCH IS FOCUSED ON MAPPING THESE MANIFESTATIONS TO SPECIFIC NEURAL PATHWAYS. DRUG ABUSE IS WELL KNOWN TO RECRUIT COMPONENTS OF THE MESOLIMBIC DOPAMINE SYSTEM, INCLUDING THE NUCLEUS ACCUMBENS AND VENTRAL TEGMENTAL AREA. IN ADDITION, ALTERED FUNCTION OF A WIDE VARIETY OF BRAIN REGIONS IS TIGHTLY ASSOCIATED WITH SPECIFIC MANIFESTATIONS OF DRUG ABUSE. THESE REGIONS PERIPHERAL TO THE MESOLIMBIC PATHWAY LIKELY PLAY A ROLE IN SPECIFIC OBSERVED COMORBIDITIES AND ENDOPHENOTYPES THAT CAN FACILITATE, OR BE CAUSED BY, SUBSTANCE ABUSE. ALTERATIONS IN SYNAPTIC STRUCTURE, FUNCTION, AND CONNECTIVITY, AS WELL AS EPIGENETIC AND GENETIC MECHANISMS ARE THOUGHT TO UNDERLIE THE PATHOLOGIES OF ADDICTION. IN PRECLINICAL MODELS, THESE PERSISTENT CHANGES ARE STUDIED AT THE LEVELS OF MOLECULAR PHARMACOLOGY AND BIOCHEMISTRY, EX VIVO AND IN VIVO ELECTROPHYSIOLOGY, RADIOGRAPHY, AND BEHAVIOR. COORDINATING RESEARCH EFFORTS ACROSS THESE DISCIPLINES AND EXAMINING CELL TYPE- AND CIRCUIT-SPECIFIC PHENOMENA ARE CRUCIAL COMPONENTS FOR TRANSLATING PRECLINICAL FINDINGS TO VIABLE MEDICAL INTERVENTIONS THAT EFFECTIVELY TREAT ADDICTION AND RELATED DISORDERS. WIRES COGN SCI 2014, 5:151-171. DOI: 10.1002/WCS.1273 CONFLICT OF INTEREST: THE AUTHORS HAVE DECLARED NO CONFLICTS OF INTEREST FOR THIS ARTICLE. FOR FURTHER RESOURCES RELATED TO THIS ARTICLE, PLEASE VISIT THE WIRES WEBSITE. 2014