1 3092 92 GENOMIC AND EPIGENOMIC MECHANISMS OF GLUCOCORTICOIDS IN THE BRAIN. FOLLOWING THE DISCOVERY OF GLUCOCORTICOID RECEPTORS IN THE HIPPOCAMPUS AND OTHER BRAIN REGIONS, RESEARCH HAS FOCUSED ON UNDERSTANDING THE EFFECTS OF GLUCOCORTICOIDS IN THE BRAIN AND THEIR ROLE IN REGULATING EMOTION AND COGNITION. GLUCOCORTICOIDS ARE ESSENTIAL FOR ADAPTATION TO STRESSORS (ALLOSTASIS) AND IN MALADAPTATION RESULTING FROM ALLOSTATIC LOAD AND OVERLOAD. ALLOSTATIC OVERLOAD, WHICH CAN OCCUR DURING CHRONIC STRESS, CAN RESHAPE THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS THROUGH EPIGENETIC MODIFICATION OF GENES IN THE HIPPOCAMPUS, HYPOTHALAMUS AND OTHER STRESS-RESPONSIVE BRAIN REGIONS. GLUCOCORTICOIDS EXERT THEIR EFFECTS ON THE BRAIN THROUGH GENOMIC MECHANISMS THAT INVOLVE BOTH GLUCOCORTICOID RECEPTORS AND MINERALOCORTICOID RECEPTORS DIRECTLY BINDING TO DNA, AS WELL AS BY NON-GENOMIC MECHANISMS. FURTHERMORE, GLUCOCORTICOIDS SYNERGIZE BOTH GENOMICALLY AND NON-GENOMICALLY WITH NEUROTRANSMITTERS, NEUROTROPHIC FACTORS, SEX HORMONES AND OTHER STRESS MEDIATORS TO SHAPE AN ORGANISM'S PRESENT AND FUTURE RESPONSES TO A STRESSFUL ENVIRONMENT. HERE, WE DISCUSS THE MECHANISMS OF GLUCOCORTICOID ACTION IN THE BRAIN AND REVIEW HOW GLUCOCORTICOIDS INTERACT WITH STRESS MEDIATORS IN THE CONTEXT OF ALLOSTASIS, ALLOSTATIC LOAD AND STRESS-INDUCED NEUROPLASTICITY. 2017 2 2269 37 EPIGENETIC PROGRAMMING OF THE NEUROENDOCRINE STRESS RESPONSE BY ADULT LIFE STRESS. THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS IS CRITICALLY INVOLVED IN THE NEUROENDOCRINE REGULATION OF STRESS ADAPTATION, AND THE RESTORATION OF HOMEOSTASIS FOLLOWING STRESS EXPOSURE. DYSREGULATION OF THIS AXIS IS ASSOCIATED WITH STRESS-RELATED PATHOLOGIES LIKE MAJOR DEPRESSIVE DISORDER, POST-TRAUMATIC STRESS DISORDER, PANIC DISORDER AND CHRONIC ANXIETY. IT HAS LONG BEEN UNDERSTOOD THAT STRESS DURING EARLY LIFE CAN HAVE A SIGNIFICANT LASTING INFLUENCE ON THE DEVELOPMENT OF THE NEUROENDOCRINE SYSTEM AND ITS NEURAL REGULATORS, PARTIALLY BY MODIFYING EPIGENETIC REGULATION OF GENE EXPRESSION, WITH IMPLICATIONS FOR HEALTH AND WELL-BEING IN LATER LIFE. EVIDENCE IS ACCUMULATING THAT EPIGENETIC PLASTICITY ALSO EXTENDS TO ADULTHOOD, PROPOSING IT AS A MECHANISM BY WHICH PSYCHOLOGICAL TRAUMA LATER IN LIFE CAN LONG-LASTINGLY AFFECT HPA AXIS FUNCTION, BRAIN PLASTICITY, NEURONAL FUNCTION AND BEHAVIOURAL ADAPTATION TO NEUROPSYCHOLOGICAL STRESS. FURTHER CORROBORATING THIS CLAIM IS THE PHENOMENON THAT THESE EPIGENETIC CHANGES CORRELATE WITH THE BEHAVIOURAL CONSEQUENCES OF TRAUMA EXPOSURE. THEREBY, EPIGENETIC MODIFICATIONS PROVIDE A PUTATIVE MOLECULAR MECHANISM BY WHICH THE BEHAVIOURAL PHENOTYPE AND TRANSCRIPTIONAL/TRANSLATIONAL POTENTIAL OF GENES INVOLVED IN HPA AXIS REGULATION CAN CHANGE DRASTICALLY IN RESPONSE TO ENVIRONMENTAL CHALLENGES, AND APPEAR AN IMPORTANT TARGET FOR TREATMENT OF STRESS-RELATED DISORDERS. HOWEVER, IMPROVED INSIGHT IS REQUIRED TO INCREASE THEIR THERAPEUTIC (DRUG) POTENTIAL. HERE, WE PROVIDE AN OVERVIEW OF THE GROWING BODY OF LITERATURE DESCRIBING THE EPIGENETIC MODULATION OF THE (PRIMARILY NEUROENDOCRINE) STRESS RESPONSE AS A CONSEQUENCE OF ADULT LIFE STRESS AND INTERPRET THE IMPLICATIONS FOR, AND THE CHALLENGES INVOLVED IN APPLYING THIS KNOWLEDGE TO, THE IDENTIFICATION AND TREATMENT OF STRESS-RELATED PSYCHIATRIC DISORDERS. 2017 3 3405 39 HOW STRESS GETS UNDER THE SKIN: EARLY LIFE ADVERSITY AND GLUCOCORTICOID RECEPTOR EPIGENETIC REGULATION. EARLY LIFE ADVERSITY IS ASSOCIATED WITH BOTH PERSISTENT DISRUPTIONS IN THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS AND PSYCHIATRIC SYMPTOMS. GLUCOCORTICOID RECEPTORS (GRS), WHICH ARE ENCODED BY THE NR3C1 GENE, BIND TO CORTISOL AND OTHER GLUCOCORTICOIDS TO CREATE A NEGATIVE FEEDBACK LOOP WITHIN THE HPA AXIS TO REGULATE THE BODY'S NEUROENDOCRINE RESPONSE TO STRESS. EXCESS METHYLATION OF A PROMOTER SEQUENCE WITHIN NR3C1 THAT ATTENUATES GR EXPRESSION, HOWEVER, HAS BEEN ASSOCIATED WITH BOTH EARLY LIFE ADVERSITY AND PSYCHOPATHOLOGY. AS CRITICAL REGULATORS WITHIN THE HPA AXIS, GRS AND THEIR EPIGENETIC REGULATION MAY MEDIATE THE LINK BETWEEN EARLY LIFE ADVERSITY AND THE ONSET OF PSYCHOPATHOLOGY. THE PRESENT REVIEW DISCUSSES THIS WORK AS ONE MECHANISM BY WHICH STRESS MAY GET UNDER THE SKIN TO DISRUPT HPA FUNCTIONING AT AN EPIGENETIC LEVEL AND CREATE LONG-LASTING VULNERABILITIES IN THE STRESS REGULATORY SYSTEM THAT SUBSEQUENTLY PREDISPOSE INDIVIDUALS TO PSYCHOPATHOLOGY. SPANNING PRENATAL INFLUENCES TO CRITICAL PERIODS OF EARLY LIFE AND ADOLESCENCE, WE DETAIL THE IMPACT THAT EARLY ADVERSITY HAS ON GR EXPRESSION, PHYSIOLOGICAL RESPONSES TO STRESS, AND THEIR IMPLICATIONS FOR LONG-TERM STRESS MANAGEMENT. WE NEXT PROPOSE A DUAL TRANSMISSION HYPOTHESIS REGARDING BOTH GENOMIC AND NON-GENOMIC MECHANISMS BY WHICH CHRONIC AND ACUTE STRESS PROPAGATE THROUGH NUMEROUS GENERATIONS. LASTLY, WE OUTLINE SEVERAL DIRECTIONS FOR FUTURE RESEARCH, INCLUDING POTENTIAL REVERSIBILITY OF METHYLATION PATTERNS AND ITS FUNCTIONAL IMPLICATIONS, VARIATION IN BEHAVIOR DETERMINED SOLELY BY NR3C1, AND CONSENSUS ON WHICH SPECIFIC PROMOTER REGIONS SHOULD BE STUDIED. 2018 4 291 32 AGING AND STRESS: PAST HYPOTHESES, PRESENT APPROACHES AND PERSPECTIVES. BRAIN AGING HAS BEEN SUGGESTED TO BE CONDITIONED BY AN EXCESSIVE GLUCOCORTIOID SECRETION LEADING TO DAMAGES ON BRAIN AREAS INVOLVED NOT ONLY IN COGNITIVE AND EMOTIONAL PROCESSES BUT ALSO IN THE CONTROL OF THE ACTIVITY OF THE HYPOTHALAMIC-PITUITARY ADRENAL AXIS. THIS REVIEW DESCRIBES SOME OF THE HYPOTHESIS THAT TRY TO EXPLAIN THE RELATION BETWEEN THE DYSREGULATION OF THE STRESS RESPONSE AND BRAIN AGING, FOCUSING ON CORTICOSTERONE BUT ALSO ON NEUROTRANSMISSION IN THE HIPPOCAMPUS, THE PREFRONTAL CORTEX AND THE AMYGDALA. MOREOVER, DIFFERENT MOLECULAR FACTORS CAN ACCOUNT FOR AN ENHANCED VULNERABILITY OF THE AGED BRAIN TO STRESS EXPOSURE, SPECIALLY FOR RESILIENCE. AMONG THEM, GOOD CANDIDATES COULD BE THOSE MECHANISMS DETERMINING THE LEVELS OF CORTICOSTERONE IN THE BRAIN, SEVERAL MOLECULES DOWNSTREAM GLUCOCORTICOID RECEPTOR ACTIVATION (IE: HEAT SHOCK PROTEINS, BAG-1) OR EVEN THE EPIGENETIC PROGRAMMING OF THE HPA AXIS IN EARLY STAGES. IN CONCLUSION, GENETIC AND ENVIRONMENTAL FACTORS (EARLY LIFE STRESS, CHRONIC STRESS DURING ADULTHOOD) CAN PRODUCE AN ENHANCED VULNERABILITY AND A REDUCED RESILIENCE OF THE BRAIN TO SUBSEQUENT STRESS EXPOSURES OR TO METABOLIC CHALLENGES LEADING, IN TURN, TO AN UNSUCCESSFUL AGING OF THE BRAIN. HOWEVER, RESULTS OBTAINED WITH THE USE OF THE ENVIRONMENTAL ENRICHMENT MODEL IN ANIMALS, ADDED TO SEVERAL RESULTS IN HUMANS ALSO DESCRIBED IN THIS REVIEW SUGGEST THAT POSITIVE ENVIRONMENTAL FACTORS (COGNITIVE-DEMANDING TASKS OR PHYSICAL EXERCISE) CAN HELP TO MAINTAIN NEURONAL PLASTICITY DURING AGING AND TO PROTECT THE BRAIN AGAINST THE DAMAGING EFFECTS OF STRESS EXPOSURE. 2011 5 235 26 ADDING FUEL TO THE FIRE: THE IMPACT OF STRESS ON THE AGEING BRAIN. BOTH AGEING AND CHRONIC STRESS ARE ASSOCIATED WITH ALTERED BRAIN PLASTICITY, DYSREGULATION OF THE IMMUNE SYSTEM, AND AN INCREASED RISK OF DEVELOPING BRAIN DISORDERS; ALL OF WHICH HAVE CONSEQUENCES FOR COGNITIVE AND EMOTIONAL PROCESSING. HERE WE EXAMINE THE SIMILARITIES BETWEEN BEHAVIOURAL CHANGES DURING AGEING AND STRESS ALTERED BEHAVIOURS (ANXIETY, DEPRESSIVE-LIKE BEHAVIOUR, COGNITION, AND SOCIABILITY) IN RODENTS AND HUMANS. THE MOLECULAR MECHANISMS HYPOTHESISED TO MEDIATE AGE-RELATED CHANGES IN BRAIN FUNCTION INCLUDING DYSFUNCTION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS, DYSREGULATION OF NEUROTRANSMISSION AND NEUROTROPHIC FACTOR SIGNALLING, INCREASED INFLAMMATORY STATE, GENETIC AND EPIGENETIC CHANGES, OXIDATIVE STRESS, METABOLIC CHANGES, AND CHANGES IN THE MICROBIOTA-GUT-BRAIN AXIS ARE DISCUSSED. FINALLY, WE EXPLORE HOW THE ALREADY STRESSED AGED BRAIN PSYCHOLOGICALLY AND PHYSIOLOGICALLY RESPONDS TO EXTERNAL STRESSORS. 2015 6 3151 43 GLUCOCORTICOIDS, EPIGENETIC CONTROL AND STRESS RESILIENCE. GLUCOCORTICOID HORMONES PLAY A PIVOTAL ROLE IN THE RESPONSE TO STRESSFUL CHALLENGES. THE SURGE IN GLUCOCORTICOID HORMONE SECRETION AFTER STRESS NEEDS TO BE TIGHTLY CONTROLLED WITH CHARACTERISTICS LIKE PEAK HEIGHT, CURVATURE AND DURATION DEPENDING ON THE NATURE AND SEVERITY OF THE CHALLENGE. THIS IS IMPORTANT AS CHRONIC HYPER- OR HYPO-RESPONSES ARE DETRIMENTAL TO HEALTH DUE TO INCREASING THE RISK FOR DEVELOPING A STRESS-RELATED MENTAL DISORDER. PROPER GLUCOCORTICOID RESPONSES TO STRESS ARE CRITICAL FOR ADAPTATION. THEREFORE, THE TIGHT CONTROL OF BASELINE AND STRESS-EVOKED GLUCOCORTICOID SECRETION ARE IMPORTANT CONSTITUENTS OF AN ORGANISM'S RESILIENCE. HERE, WE ADDRESS A NUMBER OF MECHANISMS THAT ILLUSTRATE THE MULTITUDE AND COMPLEXITY OF MEASURES SAFEGUARDING THE CONTROL OF GLUCOCORTICOID FUNCTION. THESE MECHANISMS INCLUDE THE CONTROL OF MINERALOCORTICOID (MR) AND GLUCOCORTICOID RECEPTOR (GR) OCCUPANCY AND CONCENTRATION, THE DYNAMIC CONTROL OF FREE GLUCOCORTICOID HORMONE AVAILABILITY BY CORTICOSTEROID-BINDING GLOBULIN (CBG), AND THE CONTROL EXERTED BY GLUCOCORTICOIDS AT THE SIGNALING, EPIGENETIC AND GENOMIC LEVEL ON GENE TRANSCRIPTIONAL RESPONSES TO STRESS. WE REVIEW THE BENEFICIAL EFFECTS OF REGULAR EXERCISE ON HPA AXIS AND SLEEP PHYSIOLOGY, AND COGNITIVE AND ANXIETY-RELATED BEHAVIOR. FURTHERMORE, WE DESCRIBE THAT, POSSIBLY THROUGH CHANGES IN THE GABAERGIC SYSTEM, EXERCISE REDUCES THE IMPACT OF STRESS ON A SIGNALING PATHWAY SPECIFICALLY IN THE DENTATE GYRUS THAT IS STRONGLY IMPLICATED IN THE BEHAVIORAL RESPONSE TO THAT STRESSOR. THESE OBSERVATIONS UNDERLINE THE IMPACT OF LIFE STYLE ON STRESS RESILIENCE. FINALLY, WE ADDRESS HOW SINGLE NUCLEOTIDE POLYMORPHISMS (SNPS) AFFECTING GLUCOCORTICOID ACTION CAN COMPROMISE STRESS RESILIENCE, WHICH BECOMES MOST APPARENT UNDER CONDITIONS OF CHILDHOOD ABUSE. 2015 7 6228 30 THE LINKS BETWEEN STRESS AND DEPRESSION: PSYCHONEUROENDOCRINOLOGICAL, GENETIC, AND ENVIRONMENTAL INTERACTIONS. THE ROLE OF STRESS IN THE ORIGIN AND DEVELOPMENT OF DEPRESSION MAY BE CONCEIVED AS THE RESULT OF MULTIPLE CONVERGING FACTORS, INCLUDING THE CHRONIC EFFECT OF ENVIRONMENTAL STRESSORS AND THE LONG-LASTING EFFECTS OF STRESSFUL EXPERIENCES DURING CHILDHOOD, ALL OF WHICH MAY INDUCE PERSISTENT HYPERACTIVITY OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS. THESE CHANGES, INCLUDING INCREASED AVAILABILITY OF CORTICOTROPIN-RELEASING FACTOR AND CORTISOL, ARE ALSO ASSOCIATED WITH HYPERACTIVITY OF THE AMYGDALA, HYPOACTIVITY OF THE HIPPOCAMPUS, AND DECREASED SEROTONERGIC NEUROTRANSMISSION, WHICH TOGETHER RESULT IN INCREASED VULNERABILITY TO STRESS. THE ROLE OF OTHER MONOAMINERGIC NEUROTRANSMITTERS, GENETIC POLYMORPHISMS, EPIGENETIC MECHANISMS, INFLAMMATORY PROCESSES, AND ALTERED COGNITIVE PROCESSING HAS ALSO BEEN CONSIDERED IN THE DEVELOPMENT OF A COMPREHENSIVE MODEL OF THE INTERACTIONS BETWEEN DIFFERENT FACTORS OF VULNERABILITY. FURTHER UNDERSTANDING OF THE UNDERLYING MECHANISMS THAT LINK THESE FACTORS MAY CONTRIBUTE SIGNIFICANTLY TO THE DEVELOPMENT OF MORE EFFECTIVE TREATMENTS AND PREVENTIVE STRATEGIES IN THE INTERFACE BETWEEN STRESS AND MOOD DISORDERS. 2016 8 3313 31 HIPPOCAMPAL BDNF IN PHYSIOLOGICAL CONDITIONS AND SOCIAL ISOLATION. EXPOSURE OF AN ORGANISM TO CHRONIC PSYCHOSOCIAL STRESS MAY AFFECT BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) EXPRESSION THAT HAS BEEN IMPLICATED IN THE ETIOLOGY OF PSYCHIATRIC DISORDERS, SUCH AS DEPRESSION. GIVEN THAT DEPRESSION IN HUMANS HAS BEEN LINKED WITH SOCIAL STRESS, THE CHRONIC SOCIAL STRESS PARADIGMS FOR MODELING PSYCHIATRIC DISORDERS IN ANIMALS HAVE THUS BEEN DEVELOPED. CHRONIC SOCIAL ISOLATION IN ANIMAL MODELS GENERALLY CAUSES CHANGES IN HYPOTHALAMIC-PITUITARY-ADRENAL AXIS FUNCTIONING, ASSOCIATED WITH ANXIETY- AND DEPRESSIVE-LIKE BEHAVIORS. ALSO, THIS CHRONIC STRESS CAUSES DOWNREGULATION OF BDNF PROTEIN AND MRNA IN THE HIPPOCAMPUS, A STRESS-SENSITIVE BRAIN REGION CLOSELY RELATED TO THE PATHOPHYSIOLOGY OF DEPRESSION. IN THIS REVIEW, WE DISCUSS THE CURRENT KNOWLEDGE REGARDING THE STRUCTURE, FUNCTION, INTRACELLULAR SIGNALING, INTER-INDIVIDUAL DIFFERENCES AND EPIGENETIC REGULATION OF BDNF IN BOTH PHYSIOLOGICAL CONDITIONS AND DEPRESSION AND CHANGES IN CORTICOSTERONE LEVELS, AS A MARKER OF STRESS RESPONSE. SINCE BDNF LEVELS ARE AGE DEPENDENT IN HUMANS AND RODENTS, THIS REVIEW WILL ALSO HIGHLIGHT THE EFFECTS OF ADOLESCENT AND ADULT CHRONIC SOCIAL ISOLATION MODELS OF BOTH GENDERS ON THE BDNF EXPRESSION. 2017 9 1981 26 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 10 248 35 ADVANCE IN STRESS FOR DEPRESSIVE DISORDER. STRESS IS AN ADAPTIVE RESPONSE TO ENVIRONMENT AVERSIVE STIMULI AND A COMMON LIFE EXPERIENCE OF ONE'S DAILY LIFE. CHRONIC OR EXCESSIVE STRESS ESPECIALLY THAT HAPPENED IN EARLY LIFE IS FOUND TO BE DELETERIOUS TO INDIVIDUAL'S PHYSICAL AND MENTAL HEALTH, WHICH IS HIGHLY RELATED TO DEPRESSIVE DISORDERS ONSET. STRESSFUL LIFE EVENTS ARE CONSISTENTLY CONSIDERED TO BE THE HIGH-RISK FACTORS OF ENVIRONMENT FOR PREDISPOSING DEPRESSIVE DISORDERS. IN LINKING STRESSFUL LIFE EVENTS WITH DEPRESSIVE DISORDER ONSET, DYSREGULATED HPA AXIS ACTIVITY IS SUPPOSED TO PLAY AN IMPORTANT ROLE IN MEDIATING AVERSIVE IMPACTS OF LIFE STRESS ON BRAIN STRUCTURE AND FUNCTION. INCREASING EVIDENCE HAVE INDICATED THE STRONG ASSOCIATION OF STRESS, ESPECIALLY THE CHRONIC STRESS AND EARLY LIFE STRESS, WITH DEPRESSIVE DISORDERS DEVELOPMENT, WHILE THE ASSOCIATION OF STRESS WITH DEPRESSION IS MODERATED BY GENETIC RISK FACTORS, INCLUDING POLYMORPHISM OF SERT, BDNF, GR, FKBP5, MR, AND CRHR1. MEANWHILE, STRESSFUL LIFE EXPERIENCE PARTICULARLY EARLY LIFE STRESS WILL EXERT EPIGENETIC MODIFICATION IN THESE RISK GENES VIA DNA METHYLATION AND MIRNA REGULATION TO GENERATE LONG-LASTING EFFECTS ON THESE GENES EXPRESSION, WHICH IN TURN CAUSE BRAIN STRUCTURAL AND FUNCTIONAL ALTERATION, AND FINALLY INCREASE THE VULNERABILITY TO DEPRESSIVE DISORDERS. THEREFORE, THE INTERACTION OF ENVIRONMENT WITH GENE, IN WHICH STRESSFUL LIFE EXPOSURE INTERPLAY WITH GENETIC RISK FACTORS AND EPIGENETIC MODIFICATION, IS ESSENTIAL IN PREDICTING DEPRESSIVE DISORDERS DEVELOPMENT. AS THE MEDIATOR OF ENVIRONMENTAL RISK FACTORS, STRESS WILL FUNCTION TOGETHER WITH GENETIC AND EPIGENETIC MECHANISM TO INFLUENCE BRAIN STRUCTURE AND FUNCTION, PHYSIOLOGY AND PSYCHOLOGY, AND FINALLY THE VULNERABILITY TO DEPRESSIVE DISORDERS. 2019 11 2386 26 EPIGENETIC REGULATORY MECHANISMS IN STRESS-INDUCED BEHAVIOR. STRESS RESPONSE IS CONSIDERED TO HAVE ADAPTIVE VALUE FOR ORGANISMS FACED WITH STRESSFUL CONDITION. CHRONIC STRESS HOWEVER ADVERSELY AFFECTS THE PHYSIOLOGY AND MAY LEAD TO NEUROPSYCHIATRIC DISORDERS. REPEATED STRESSFUL EVENTS IN ANIMAL MODELS HAVE BEEN SHOWN TO CAUSE LONG-LASTING CHANGES IN NEURAL CIRCUITRIES AT MOLECULAR, CELLULAR, AND PHYSIOLOGICAL LEVEL, LEADING TO DISORDERS OF MOOD AS WELL AS COGNITION. MOLECULAR STUDIES IN RECENT YEARS HAVE IMPLICATED DIVERSE EPIGENETIC MECHANISMS, INCLUDING HISTONE MODIFICATIONS, DNA METHYLATION, AND NONCODING RNAS, THAT UNDERLIE DYSREGULATION OF GENES IN THE AFFECTED NEURAL CIRCUITRIES IN CHRONIC STRESS-INDUCED PATHOPHYSIOLOGY. A REVIEW OF THE MYRIAD EPIGENETIC REGULATORY MECHANISMS ASSOCIATED WITH NEURAL AND BEHAVIORAL RESPONSES IN ANIMAL MODELS OF STRESS-INDUCED NEUROPSYCHIATRIC DISORDERS IS PRESENTED HERE. THE REVIEW ALSO DEALS WITH CLINICAL EVIDENCE OF THE EPIGENETIC DYSREGULATION OF GENES IN PSYCHIATRIC DISORDERS WHERE CHRONIC STRESS APPEARS TO UNDERLIE THE ETIOPATHOLOGY. 2014 12 4118 32 MECHANISMS OF BRAIN GLUCOCORTICOID RESISTANCE IN STRESS-INDUCED PSYCHOPATHOLOGIES. EXPOSURE TO STRESS ACTIVATES THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS AND LEADS TO INCREASED LEVELS OF GLUCOCORTICOID (GC) HORMONES. PROLONGED ELEVATION OF GC LEVELS CAUSES NEURONAL DYSFUNCTION, DECREASES THE DENSITY OF SYNAPSES, AND IMPAIRS NEURONAL PLASTICITY. DECREASED SENSITIVITY TO GLUCOCORTICOIDS (GLUCOCORTICOID RESISTANCE) THAT DEVELOPS AS A RESULT OF CHRONIC STRESS IS ONE OF THE CHARACTERISTIC FEATURES OF STRESS-INDUCED PSYCHOPATHOLOGIES. IN THIS ARTICLE, WE REVIEWED THE PUBLISHED DATA ON PROPOSED MOLECULAR MECHANISMS THAT CONTRIBUTE TO THE DEVELOPMENT OF GLUCOCORTICOID RESISTANCE IN BRAIN, INCLUDING CHANGES IN THE EXPRESSION OF THE GLUCOCORTICOID RECEPTOR (GR) GENE, BIOSYNTHESIS OF GR ISOFORMS, AND GR POSTTRANSLATIONAL MODIFICATIONS. WE ALSO PRESENT DATA ON ALTERATIONS IN THE EXPRESSION OF THE FKBP5 GENE ENCODING THE MAIN COMPONENT OF CELL ULTRA-SHORT NEGATIVE FEEDBACK LOOP OF GC SIGNALING REGULATION. RECENT DISCOVERIES ON STRESS- AND GR-INDUCED CHANGES IN EPIGENETIC MODIFICATION PATTERNS AS WELL AS NORMALIZING ACTION OF ANTIDEPRESSANTS ARE DISCUSSED. GR AND FKBP5 GENE POLYMORPHISMS ASSOCIATED WITH STRESS-INDUCED PSYCHOPATHOLOGIES ARE DESCRIBED, AND THEIR ROLE IN GLUCOCORTICOID RESISTANCE IS DISCUSSED. 2017 13 678 38 BRAIN DEVELOPMENT UNDER STRESS: HYPOTHESES OF GLUCOCORTICOID ACTIONS REVISITED. ONE OF THE CONUNDRUMS IN TODAY'S STRESS RESEARCH IS WHY SOME INDIVIDUALS FLOURISH AND OTHERS PERISH UNDER SIMILAR STRESSFUL CONDITIONS. IT IS RECOGNIZED THAT THIS INDIVIDUAL VARIABILITY IN ADAPTATION TO STRESS DEPENDS ON THE OUTCOME OF THE INTERACTION OF GENETIC AND COGNITIVE/EMOTIONAL INPUTS IN WHICH GLUCOCORTICOID HORMONES AND RECEPTORS PLAY A CRUCIAL ROLE. HENCE ONE APPROACH TOWARDS UNDERSTANDING INDIVIDUAL VARIATION IN STRESS COPING IS HOW GLUCOCORTICOID ACTIONS CAN CHANGE FROM PROTECTIVE TO HARMFUL. TO ADDRESS THIS QUESTION WE FOCUS ON FOUR HYPOTHESES THAT ARE CONNECTED AND NOT MUTUAL EXCLUSIVE. FIRST, THE CLASSICAL GLUCOCORTICOID CASCADE HYPOTHESIS, IN WHICH THE INABILITY TO COPE WITH CHRONIC STRESS CAUSES A VICIOUS CYCLE OF EXCESS GLUCOCORTICOID AND DOWNREGULATION OF GLUCOCORTICOID RECEPTORS (GR) IN THE HIPPOCAMPUS TRIGGERING A FEED-FORWARD CASCADE OF DEGENERATION AND DISEASE. SECOND, THE BALANCE HYPOTHESIS, WHICH TAKES ALSO THE LIMBIC MINERALOCORTICOID RECEPTORS (MR) INTO ACCOUNT AND PROPOSES THAT AN INTEGRAL LIMBIC MR:GR IMBALANCE IS CAUSAL TO ALTERED PROCESSING OF INFORMATION IN CIRCUITS UNDERLYING FEAR, REWARD, SOCIAL BEHAVIOUR AND RESILIENCE, DYSREGULATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS AND IMPAIRMENT OF BEHAVIOURAL ADAPTATION. THE MR:GR BALANCE IS ALTERED BY GENE VARIANTS OF THESE RECEPTOR COMPLEXES AND EXPERIENCE-RELATED FACTORS, WHICH CAN INDUCE LASTING EPIGENETIC CHANGES IN THE EXPRESSION OF THESE RECEPTORS. A PARTICULAR POTENT EPIGENETIC STIMULUS IS THE MATERNAL ENVIRONMENT WHICH IS FUNDAMENTAL FOR THE MATERNAL MEDIATION HYPOTHESIS. THE OUTCOME OF PERINATAL GENE X ENVIRONMENT INTERACTION, AND THUS OF MR:GR-MEDIATED FUNCTIONS DEPENDS HOWEVER, ON THE DEGREE OF 'MATCHING' WITH ENVIRONMENTAL DEMANDS IN LATER LIFE. THE PREDICTIVE ADAPTATION HYPOTHESIS THEREFORE PRESENTS A CONCEPTUAL FRAMEWORK TO EXAMINE THE ROLE OF GLUCOCORTICOIDS IN UNDERSTANDING INDIVIDUAL PHENOTYPIC DIFFERENCES IN STRESS-RELATED BEHAVIOURS OVER THE LIFESPAN. 2010 14 2264 38 EPIGENETIC PROGRAMMING BY STRESS AND GLUCOCORTICOIDS ALONG THE HUMAN LIFESPAN. PSYCHOSOCIAL STRESS TRIGGERS A SET OF BEHAVIORAL, NEURAL, HORMONAL, AND MOLECULAR RESPONSES THAT CAN BE A DRIVING FORCE FOR SURVIVAL WHEN ADAPTIVE AND TIME-LIMITED, BUT MAY ALSO CONTRIBUTE TO A HOST OF DISEASE STATES IF DYSREGULATED OR CHRONIC. THE BENEFICIAL OR DETRIMENTAL EFFECTS OF STRESS ARE LARGELY MEDIATED BY THE HYPOTHALAMIC-PITUITARY AXIS, A HIGHLY CONSERVED NEUROHORMONAL CASCADE THAT CULMINATES IN SYSTEMIC SECRETION OF GLUCOCORTICOIDS. GLUCOCORTICOIDS ACTIVATE THE GLUCOCORTICOID RECEPTOR, A UBIQUITOUS NUCLEAR RECEPTOR THAT NOT ONLY CAUSES WIDESPREAD CHANGES IN TRANSCRIPTIONAL PROGRAMS, BUT ALSO INDUCES LASTING EPIGENETIC MODIFICATIONS IN MANY TARGET TISSUES. WHILE THE EPIGENOME REMAINS SENSITIVE TO STRESSORS THROUGHOUT LIFE, WE PROPOSE TWO KEY PRINCIPLES THAT MAY GOVERN THE EPIGENETICS OF STRESS AND GLUCOCORTICOIDS ALONG THE LIFESPAN: FIRST, THE PRESENCE OF DISTINCT LIFE PERIODS, DURING WHICH THE EPIGENOME SHOWS HEIGHTENED PLASTICITY TO STRESS EXPOSURE, SUCH AS IN EARLY DEVELOPMENT AND AT ADVANCED AGE; AND, SECOND, THE POTENTIAL OF STRESS-INDUCED EPIGENETIC CHANGES TO ACCUMULATE THROUGHOUT LIFE BOTH IN SELECT CHROMATIN REGIONS AND AT THE GENOME-WIDE LEVEL. THESE PRINCIPLES HAVE IMPORTANT CLINICAL AND TRANSLATIONAL IMPLICATIONS, AND THEY SHOW STRIKING PARALLELS WITH THE EXISTENCE OF SENSITIVE DEVELOPMENTAL PERIODS AND THE CUMULATIVE IMPACT OF STRESSFUL EXPERIENCES ON THE DEVELOPMENT OF STRESS-RELATED PHENOTYPES. WE HOPE THAT THIS CONCEPTUAL MECHANISTIC FRAMEWORK WILL STIMULATE FRUITFUL RESEARCH THAT AIMS AT UNRAVELING THE MOLECULAR PATHWAYS THROUGH WHICH OUR LIFE STORIES SCULPT GENOMIC FUNCTION TO CONTRIBUTE TO COMPLEX BEHAVIORAL AND SOMATIC PHENOTYPES. 2017 15 5662 32 SEXUAL DIMORPHISM IN GLUCOCORTICOID STRESS RESPONSE. CHRONIC STRESS IS ENCOUNTERED IN OUR EVERYDAY LIFE AND IS THOUGHT TO CONTRIBUTE TO A NUMBER OF DISEASES. MANY OF THESE STRESS-RELATED DISORDERS DISPLAY A SEX BIAS. BECAUSE GLUCOCORTICOID HORMONES ARE THE MAIN BIOLOGICAL MEDIATOR OF CHRONIC STRESS, RESEARCHERS HAVE BEEN INTERESTED IN UNDERSTANDING THE SEXUAL DIMORPHISM IN GLUCOCORTICOID STRESS RESPONSE TO BETTER EXPLAIN THE SEX BIAS IN STRESS-RELATED DISEASES. ALTHOUGH NOT YET DEMONSTRATED FOR GLUCOCORTICOID REGULATION, SEX CHROMOSOMES DO INFLUENCE SEX-SPECIFIC BIOLOGY AS SOON AS CONCEPTION. THEN A TRANSIENT RISE IN TESTOSTERONE START TO SHAPE THE MALE BRAIN DURING THE PRENATAL PERIOD DIFFERENTLY TO THE FEMALE BRAIN. THESE ORGANIZATIONAL EFFECTS ARE COMPLETED JUST BEFORE PUBERTY. THE CEREBRAL REGIONS IMPLICATED IN GLUCOCORTICOID REGULATION AT REST AND AFTER STRESS ARE THEREBY IMPACTED IN A SEX-SPECIFIC MANNER. AFTER PUBERTY, THE HIGH LEVELS OF ALL GONADAL HORMONES WILL INTERACT WITH GLUCOCORTICOID HORMONES IN SPECIFIC CROSSTALK THROUGH THEIR RESPECTIVE NUCLEAR RECEPTORS. IN ADDITION, STRESS OCCURRING EARLY IN LIFE, IN PARTICULAR DURING THE PRENATAL PERIOD AND IN ADOLESCENCE WILL PRIME IN THE LONG-TERM GLUCOCORTICOID STRESS RESPONSE THROUGH EPIGENETIC MECHANISMS, AGAIN IN A SEX-SPECIFIC MANNER. ALTOGETHER, VARIOUS MOLECULAR MECHANISMS EXPLAIN SEX-SPECIFIC GLUCOCORTICOID STRESS RESPONSES THAT DO NOT EXCLUDE IMPORTANT GENDER EFFECTS IN HUMANS. 2021 16 6729 34 VULNERABILITY TO STROKE: IMPLICATIONS OF PERINATAL PROGRAMMING OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS. CHRONIC STRESS IS CAPABLE OF EXACERBATING EACH MAJOR, MODIFIABLE, ENDOGENOUS RISK FACTOR FOR CEREBROVASCULAR AND CARDIOVASCULAR DISEASE. INDEED, EXPOSURE TO STRESS CAN INCREASE BOTH THE INCIDENCE AND SEVERITY OF STROKE, PRESUMABLY THROUGH ACTIVATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS. NOW THAT CHARACTERIZATION OF THE MECHANISMS UNDERLYING EPIGENETIC PROGRAMMING OF THE HPA AXIS IS WELL UNDERWAY, THERE HAS BEEN RENEWED INTEREST IN EXAMINING THE ROLE OF EARLY ENVIRONMENT ON THE EVOLUTION OF HEALTH CONDITIONS ACROSS THE ENTIRE LIFESPAN. INDEED, NEONATAL MANIPULATIONS IN RODENTS THAT REDUCE STRESS RESPONSIVITY, AND SUBSEQUENT LIFE-TIME EXPOSURE TO GLUCOCORTICOIDS, ARE ASSOCIATED WITH A REDUCTION IN THE DEVELOPMENT OF NEUROENDOCRINE, NEUROANATOMICAL, AND COGNITIVE DYSFUNCTIONS THAT TYPICALLY PROGRESS WITH AGE. ALTHOUGH IMPROVED DAY TO DAY REGULATION OF THE HPA AXIS ALSO MAY BE ACCOMPANIED BY A DECREASE IN STROKE RISK, EVIDENCE FROM RODENT STUDIES SUGGEST THAT AN ASSOCIATED COST COULD BE INCREASED SUSCEPTIBILITY TO INFLAMMATION AND NEURONAL DEATH IN THE EVENT THAT A STROKE DOES OCCUR AND THE INDIVIDUAL IS EXPOSED TO PERSISTENTLY ELEVATED CORTICOSTEROIDS. GIVEN ITS IMPORTANCE IN REGULATION OF HEALTH AND DISEASE STATES, ANY LONG-TERM MODULATION OF THE HPA AXIS IS LIKELY TO BE ASSOCIATED WITH BOTH BENEFITS AND POTENTIAL RISKS. THE GOALS OF THIS REVIEW ARTICLE ARE TO EXAMINE (1) THE CLINICAL AND EXPERIMENTAL DATA SUGGESTING THAT NEONATAL EXPERIENCES CAN SHAPE HPA AXIS REGULATION, (2) THE INFLUENCE OF STRESS AND THE HPA AXIS ON STROKE INCIDENCE AND SEVERITY, AND (3) THE POTENTIAL FOR NEONATAL PROGRAMMING OF THE HPA AXIS TO IMPACT ADULT CEREBROVASCULAR HEALTH. 2009 17 5812 35 STRESS AND ANXIETY: STRUCTURAL PLASTICITY AND EPIGENETIC REGULATION AS A CONSEQUENCE OF STRESS. THE BRAIN IS THE CENTRAL ORGAN OF STRESS AND ADAPTATION TO STRESS BECAUSE IT PERCEIVES AND DETERMINES WHAT IS THREATENING, AS WELL AS THE BEHAVIORAL AND PHYSIOLOGICAL RESPONSES TO THE STRESSOR. THE ADULT, AS WELL AS DEVELOPING BRAIN, POSSESS A REMARKABLE ABILITY TO SHOW REVERSIBLE STRUCTURAL AND FUNCTIONAL PLASTICITY IN RESPONSE TO STRESSFUL AND OTHER EXPERIENCES, INCLUDING NEURONAL REPLACEMENT, DENDRITIC REMODELING, AND SYNAPSE TURNOVER. THIS IS PARTICULARLY EVIDENT IN THE HIPPOCAMPUS, WHERE ALL THREE TYPES OF STRUCTURAL PLASTICITY HAVE BEEN RECOGNIZED AND INVESTIGATED, USING A COMBINATION OF MORPHOLOGICAL, MOLECULAR, PHARMACOLOGICAL, ELECTROPHYSIOLOGICAL AND BEHAVIORAL APPROACHES. THE AMYGDALA AND THE PREFRONTAL CORTEX, BRAIN REGIONS INVOLVED IN ANXIETY AND FEAR, MOOD, COGNITIVE FUNCTION AND BEHAVIORAL CONTROL, ALSO SHOW STRUCTURAL PLASTICITY. ACUTE AND CHRONIC STRESS CAUSE AN IMBALANCE OF NEURAL CIRCUITRY SUBSERVING COGNITION, DECISION MAKING, ANXIETY AND MOOD THAT CAN INCREASE OR DECREASE EXPRESSION OF THOSE BEHAVIORS AND BEHAVIORAL STATES. IN THE SHORT TERM, SUCH AS FOR INCREASED FEARFUL VIGILANCE AND ANXIETY IN A THREATENING ENVIRONMENT, THESE CHANGES MAY BE ADAPTIVE; BUT, IF THE DANGER PASSES AND THE BEHAVIORAL STATE PERSISTS ALONG WITH THE CHANGES IN NEURAL CIRCUITRY, SUCH MALADAPTATION MAY NEED INTERVENTION WITH A COMBINATION OF PHARMACOLOGICAL AND BEHAVIORAL THERAPIES, AS IS THE CASE FOR CHRONIC OR MOOD ANXIETY DISORDERS. WE SHALL REVIEW CELLULAR AND MOLECULAR MECHANISMS, AS WELL AS RECENT WORK ON INDIVIDUAL DIFFERENCES IN ANXIETY-LIKE BEHAVIOR AND ALSO DEVELOPMENTAL INFLUENCES THAT BIAS HOW THE BRAIN RESPONDS TO STRESSORS. FINALLY, WE SUGGEST THAT SUCH AN APPROACH NEEDS TO BE EXTENDED TO OTHER BRAIN AREAS THAT ARE ALSO INVOLVED IN ANXIETY AND MOOD. THIS ARTICLE IS PART OF A SPECIAL ISSUE ENTITLED 'ANXIETY AND DEPRESSION'. 2012 18 2520 31 EPIGENETICS AND THE GLUCOCORTICOID RECEPTOR: A REVIEW OF THE IMPLICATIONS IN DEPRESSION. DEPRESSION IS A SERIOUS PSYCHIATRIC DISORDER THAT EFFECTS AT LEAST 350 MILLION PEOPLE WORLDWIDE TODAY. DYSREGULATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS (HPAA) IS A ROBUST FINDING IN THE PATHOPHYSIOLOGY OF DEPRESSION. THIS DYSREGULATION IS HYPOTHESIZED TO RESULT FROM ALTERED CENTRAL GLUCOCORTICOID RECEPTOR (GR) LEVELS AND/OR FUNCTION AS A CONSEQUENCE OF CHRONIC GLUCOCORTICOID (GC) RELEASE, LEADING TO RECEPTOR RESISTANCE. PIVOTAL ANIMAL AND HUMAN RESEARCH TO DATE HAS IDENTIFIED THAT EARLY LIFE EXPOSURE TO PROLONGED LEVELS OF GCS, STRESS AND/OR DEPRESSION, CAN INDUCE EPIGENETIC MODIFICATIONS AT KEY REGIONS ON THE GR GENE THAT LEAD TO ALTERATIONS IN GR EXPRESSION AND FUNCTION. EPIGENETICS PROVIDES AN ATTRACTIVE MECHANISM TO EXPLAIN HOW ONES' GENES AND ENVIRONMENT CAN INTERACT TO PRODUCE DIFFERENT DISEASE PHENOTYPES. THIS REVIEW AIMS TO COMPILE THE INFORMATION THAT HAS BEEN COLLECTED TO DATE AND TO IDENTIFY KEY AREAS FOR FURTHER INVESTIGATION. 2016 19 4642 32 NEURONAL PLASTICITY: A LINK BETWEEN STRESS AND MOOD DISORDERS. ALTHOUGH STRESS REPRESENTS THE MAJOR ENVIRONMENTAL ELEMENT OF SUSCEPTIBILITY FOR MOOD DISORDERS, THE RELATIONSHIP BETWEEN STRESS AND DISEASE REMAINS TO BE FULLY ESTABLISHED. IN THE PRESENT ARTICLE WE REVIEW THE EVIDENCE IN SUPPORT FOR A ROLE OF NEURONAL PLASTICITY, AND IN PARTICULAR OF NEUROTROPHIC FACTORS. EVEN THOUGH DECREASED LEVELS OF NOREPINEPHRINE AND SEROTONIN MAY UNDERLIE DEPRESSIVE SYMPTOMS, COMPELLING EVIDENCE NOW SUGGESTS THAT MOOD DISORDERS ARE CHARACTERIZED BY REDUCED NEURONAL PLASTICITY, WHICH CAN BE BROUGHT ABOUT BY EXPOSURE TO STRESS AT DIFFERENT STAGES OF LIFE. INDEED THE EXPRESSION OF NEUROTROPHIC MOLECULES, SUCH AS THE NEUROTROPHIN BDNF, IS REDUCED IN DEPRESSED SUBJECTS AS WELL AS IN EXPERIMENTAL ANIMALS EXPOSED TO ADVERSE EXPERIENCE AT EARLY STAGES OF LIFE OR AT ADULTHOOD. THESE CHANGES SHOW AN ANATOMICAL SPECIFICITY AND MIGHT BE SUSTAINED BY EPIGENETIC MECHANISMS. PHARMACOLOGICAL INTERVENTION MAY NORMALIZE SUCH DEFECTS AND IMPROVE NEURONAL FUNCTION THROUGH THE MODULATION OF THE SAME FACTORS THAT ARE DEFECTIVE IN DEPRESSION. SEVERAL STUDIES HAVE DEMONSTRATED THAT CHRONIC, BUT NOT ACUTE, ANTIDEPRESSANT TREATMENT INCREASES THE EXPRESSION OF BDNF AND MAY ENHANCE ITS LOCALIZATION AT SYNAPTIC LEVEL. ANTIDEPRESSANT TREATMENT CAN NORMALIZE DEFICITS IN NEUROTROPHIN EXPRESSION PRODUCED BY CHRONIC STRESS PARADIGMS, BUT MAY ALSO ALTER THE MODULATION OF BDNF UNDER ACUTE STRESSFUL CONDITIONS. IN SUMMARY, THERE IS GOOD AGREEMENT IN CONSIDERING NEURONAL PLASTICITY, AND THE EXPRESSION OF KEY PROTEINS SUCH AS THE NEUROTROPHIN BDNF, AS A CENTRAL PLAYER FOR THE EFFECTS OF STRESS ON BRAIN FUNCTION AND ITS IMPLICATION FOR PSYCHOPATHOLOGY. ACCORDINGLY, EFFECTIVE TREATMENTS SHOULD NOT LIMIT THEIR EFFECTS TO THE CONTROL OF NEUROTRANSMITTER AND HORMONAL DYSFUNCTIONS, BUT SHOULD BE ABLE TO NORMALIZE DEFECTIVE MECHANISMS THAT SUSTAIN THE IMPAIRMENT OF NEURONAL PLASTICITY. 2009 20 23 37 60 YEARS OF NEUROENDOCRINOLOGY: REDEFINING NEUROENDOCRINOLOGY: STRESS, SEX AND COGNITIVE AND EMOTIONAL REGULATION. THE DISCOVERY OF STEROID HORMONE RECEPTORS IN BRAIN REGIONS THAT MEDIATE EVERY ASPECT OF BRAIN FUNCTION HAS BROADENED THE DEFINITION OF 'NEUROENDOCRINOLOGY' TO INCLUDE THE RECIPROCAL COMMUNICATION BETWEEN THE BRAIN AND THE BODY VIA HORMONAL AND NEURAL PATHWAYS. THE BRAIN IS THE CENTRAL ORGAN OF STRESS AND ADAPTATION TO STRESS BECAUSE IT PERCEIVES AND DETERMINES WHAT IS THREATENING, AS WELL AS THE BEHAVIORAL AND PHYSIOLOGICAL RESPONSES TO THE STRESSOR. THE ADULT AND DEVELOPING BRAIN POSSESS REMARKABLE STRUCTURAL AND FUNCTIONAL PLASTICITY IN RESPONSE TO STRESS, INCLUDING NEURONAL REPLACEMENT, DENDRITIC REMODELING, AND SYNAPSE TURNOVER. STRESS CAUSES AN IMBALANCE OF NEURAL CIRCUITRY SUBSERVING COGNITION, DECISION-MAKING, ANXIETY AND MOOD THAT CAN ALTER EXPRESSION OF THOSE BEHAVIORS AND BEHAVIORAL STATES. THIS IMBALANCE, IN TURN, AFFECTS SYSTEMIC PHYSIOLOGY VIA NEUROENDOCRINE, AUTONOMIC, IMMUNE AND METABOLIC MEDIATORS. IN THE SHORT TERM, AS FOR INCREASED FEARFUL VIGILANCE AND ANXIETY IN A THREATENING ENVIRONMENT, THESE CHANGES MAY BE ADAPTIVE. BUT, IF THE DANGER PASSES AND THE BEHAVIORAL STATE PERSISTS ALONG WITH THE CHANGES IN NEURAL CIRCUITRY, SUCH MALADAPTATION MAY NEED INTERVENTION WITH A COMBINATION OF PHARMACOLOGICAL AND BEHAVIORAL THERAPIES, AS IS THE CASE FOR CHRONIC ANXIETY AND DEPRESSION. THERE ARE IMPORTANT SEX DIFFERENCES IN THE BRAIN RESPONSES TO STRESSORS THAT ARE IN URGENT NEED OF FURTHER EXPLORATION. MOREOVER, ADVERSE EARLY-LIFE EXPERIENCE, INTERACTING WITH ALLELES OF CERTAIN GENES, PRODUCE LASTING EFFECTS ON BRAIN AND BODY OVER THE LIFE-COURSE VIA EPIGENETIC MECHANISMS. WHILE PREVENTION IS MOST IMPORTANT, THE PLASTICITY OF THE BRAIN GIVES HOPE FOR THERAPIES THAT TAKE INTO CONSIDERATION BRAIN-BODY INTERACTIONS. 2015