1 5693 84 SILENCING OF MATERNAL HEPATIC GLUCOCORTICOID RECEPTOR IS ESSENTIAL FOR NORMAL FETAL DEVELOPMENT IN MICE. EXCESSIVE OR CHRONIC STRESS CAN LEAD TO A VARIETY OF DISEASES DUE TO ABERRANT ACTIVATION OF THE GLUCOCORTICOID RECEPTOR (GR), A LIGAND ACTIVATED TRANSCRIPTION FACTOR. PREGNANCY REPRESENTS A PARTICULAR WINDOW OF SENSITIVITY IN WHICH EXCESSIVE STRESS CAN HAVE ADVERSE OUTCOMES, PARTICULARLY ON THE DEVELOPING FETUS. HERE WE SHOW MATERNAL HEPATIC STRESS HORMONE RESPONSIVENESS IS DIMINISHED VIA EPIGENETIC SILENCING OF THE GLUCOCORTICOID RECEPTOR DURING PREGNANCY. PROVOCATIVELY, REINSTALLATION OF GR TO HEPATOCYTES DURING PREGNANCY BY ADENO-ASSOCIATED VIRAL TRANSDUCTION DYSREGULATES GENES INVOLVED IN PROLIFERATION, RESULTING IN IMPAIRED PREGNANCY-INDUCED HEPATOMEGALY. DISRUPTION OF THE MATERNAL HEPATIC ADAPTATION TO PREGNANCY RESULTS IN IN UTERO GROWTH RESTRICTION (IUGR). THESE DATA DEMONSTRATE PREGNANCY ANTAGONIZES THE LIVER-SPECIFIC EFFECTS OF STRESS HORMONE SIGNALING IN THE MATERNAL COMPARTMENT TO ULTIMATELY SUPPORT THE HEALTHY DEVELOPMENT OF EMBRYOS. 2019 2 1520 29 DNA METHYLATION AT DIFFERENTIALLY METHYLATED REGIONS OF IMPRINTED GENES IS RESISTANT TO DEVELOPMENTAL PROGRAMMING BY MATERNAL NUTRITION. THE NUTRITIONAL ENVIRONMENT IN WHICH THE MAMMALIAN FETUS OR INFANT DEVELOP IS RECOGNIZED AS INFLUENCING THE RISK OF CHRONIC DISEASES, SUCH AS TYPE 2 DIABETES AND HYPERTENSION, IN A PHENOMENON THAT HAS BECOME KNOWN AS DEVELOPMENTAL PROGRAMMING. THE LATE ONSET OF SUCH DISEASES IN RESPONSE TO EARLIER TRANSIENT EXPERIENCES HAS LED TO THE SUGGESTION THAT DEVELOPMENTAL PROGRAMMING MAY HAVE AN EPIGENETIC COMPONENT, BECAUSE EPIGENETIC MARKS SUCH AS DNA METHYLATION OR HISTONE TAIL MODIFICATIONS COULD PROVIDE A PERSISTENT MEMORY OF EARLIER NUTRITIONAL STATES. ONE CLASS OF GENES THAT HAS BEEN CONSIDERED A POTENTIAL TARGET OR MEDIATOR OF PROGRAMMING EVENTS IS IMPRINTED GENES, BECAUSE THESE GENES CRITICALLY DEPEND UPON EPIGENETIC MODIFICATIONS FOR CORRECT EXPRESSION AND BECAUSE MANY IMPRINTED GENES HAVE ROLES IN CONTROLLING FETAL GROWTH AS WELL AS NEONATAL AND ADULT METABOLISM. IN THIS STUDY, WE HAVE USED AN ESTABLISHED MODEL OF DEVELOPMENTAL PROGRAMMING-ISOCALORIC PROTEIN RESTRICTION TO FEMALE MICE DURING GESTATION OR LACTATION-TO EXAMINE WHETHER THERE ARE EFFECTS ON EXPRESSION AND DNA METHYLATION OF IMPRINTED GENES IN THE OFFSPRING. WE FIND THAT ALTHOUGH EXPRESSION OF SOME IMPRINTED GENES IN LIVER OF OFFSPRING IS ROBUSTLY AND SUSTAINABLY CHANGED, METHYLATION OF THE DIFFERENTIALLY METHYLATED REGIONS (DMRS) THAT CONTROL THEIR MONOALLELIC EXPRESSION REMAINS LARGELY UNALTERED. WE CONCLUDE THAT DEREGULATION OF IMPRINTING THROUGH A GENERAL EFFECT ON DMR METHYLATION IS UNLIKELY TO BE A COMMON FACTOR IN DEVELOPMENTAL PROGRAMMING. 2012 3 6133 21 THE EPIGENETIC ROLE OF VITAMIN C IN NEURODEVELOPMENT. THE MATERNAL DIET DURING PREGNANCY IS A KEY DETERMINANT OF OFFSPRING HEALTH. EARLY STUDIES HAVE LINKED POOR MATERNAL NUTRITION DURING GESTATION WITH A PROPENSITY FOR THE DEVELOPMENT OF CHRONIC CONDITIONS IN OFFSPRING. THESE CONDITIONS INCLUDE CARDIOVASCULAR DISEASE, TYPE 2 DIABETES AND EVEN COMPROMISED MENTAL HEALTH. WHILE MULTIPLE FACTORS MAY CONTRIBUTE TO THESE OUTCOMES, DISTURBED EPIGENETIC PROGRAMMING DURING EARLY DEVELOPMENT IS ONE POTENTIAL BIOLOGICAL MECHANISM. THE EPIGENOME IS PROGRAMMED PRIMARILY IN UTERO, AND DURING THIS TIME, THE DEVELOPING FETUS IS HIGHLY SUSCEPTIBLE TO ENVIRONMENTAL FACTORS SUCH AS NUTRITIONAL INSULTS. DURING NEURODEVELOPMENT, EPIGENETIC PROGRAMMING COORDINATES THE FORMATION OF PRIMITIVE CENTRAL NERVOUS SYSTEM STRUCTURES, NEUROGENESIS, AND NEUROPLASTICITY. DYSREGULATED EPIGENETIC PROGRAMMING HAS BEEN IMPLICATED IN THE AETIOLOGY OF SEVERAL NEURODEVELOPMENTAL DISORDERS SUCH AS TATTON-BROWN-RAHMAN SYNDROME. ACCORDINGLY, THERE IS GREAT INTEREST IN DETERMINING HOW MATERNAL NUTRIENT AVAILABILITY IN PREGNANCY MIGHT AFFECT THE EPIGENETIC STATUS OF OFFSPRING, AND HOW SUCH INFLUENCES MAY PRESENT PHENOTYPICALLY. IN RECENT YEARS, A NUMBER OF EPIGENETIC ENZYMES THAT ARE ACTIVE DURING EMBRYONIC DEVELOPMENT HAVE BEEN FOUND TO REQUIRE VITAMIN C AS A COFACTOR. THESE ENZYMES INCLUDE THE TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASES (TETS) AND THE JUMONJI C DOMAIN-CONTAINING HISTONE LYSINE DEMETHYLASES THAT CATALYSE THE OXIDATIVE REMOVAL OF METHYL GROUPS ON CYTOSINES AND HISTONE LYSINE RESIDUES, RESPECTIVELY. THESE ENZYMES ARE INTEGRAL TO EPIGENETIC REGULATION AND HAVE FUNDAMENTAL ROLES IN CELLULAR DIFFERENTIATION, THE MAINTENANCE OF PLURIPOTENCY AND DEVELOPMENT. THE DEPENDENCE OF THESE ENZYMES ON VITAMIN C FOR OPTIMAL CATALYTIC ACTIVITY ILLUSTRATES A POTENTIALLY CRITICAL CONTRIBUTION OF THE NUTRIENT DURING MAMMALIAN DEVELOPMENT. THESE INSIGHTS ALSO HIGHLIGHT A POTENTIAL RISK ASSOCIATED WITH VITAMIN C INSUFFICIENCY DURING PREGNANCY. THE LINK BETWEEN VITAMIN C INSUFFICIENCY AND DEVELOPMENT IS PARTICULARLY APPARENT IN THE CONTEXT OF NEURODEVELOPMENT AND HIGH VITAMIN C CONCENTRATIONS IN THE BRAIN ARE INDICATIVE OF IMPORTANT FUNCTIONAL REQUIREMENTS IN THIS ORGAN. ACCORDINGLY, THIS REVIEW CONSIDERS THE EVIDENCE FOR THE POTENTIAL IMPACT OF MATERNAL VITAMIN C STATUS ON NEURODEVELOPMENTAL EPIGENETICS. 2022 4 4983 28 PATHOPHYSIOLOGY, CELLULAR AND MOLECULAR MECHANISMS OF FOETAL GROWTH RETARDATION. IN MAMMALS, SIZE AT BIRTH IS THE OUTCOME OF LENGTH OF GESTATION AND RATE OF FOETAL GROWTH. IN THE ABSENCE OF PREMATURE DELIVERY, FOETAL SIZE WITHIN SPECIES IS DETERMINED PRINCIPALLY BY FOETAL GROWTH RATE WHICH IS DEPENDENT ON BOTH GENETIC AND EPIGENETIC FACTORS. FAILURE OF EITHER OF THESE MECHANISMS LEADS TO FOETAL GROWTH RETARDATION. IN MAMMALS, INCLUDING HUMAN INFANTS, FOETAL GROWTH RETARDATION CAN OCCUR NATURALLY OR PATHOLOGICALLY. ONE MAJOR CAUSE FOR NATURAL FOETAL GROWTH RETARDATION OR RUNTING IS THE INCREASE IN LITTER SIZE. IN MANY CASES, HOWEVER, THE CAUSE OF RUNTING IS UNKNOWN. PARENTAL GENOTYPE OR ANTIGENIC DIFFERENCES BETWEEN THE MOTHER AND THE DEVELOPING CONCEPTUS MAY BE POTENTIAL CAUSES. PATHOLOGICAL FOETAL GROWTH RETARDATION OR INTRAUTERINE GROWTH RETARDATION (IUGR) IS DUE TO GENETIC CAUSES (CHROMOSOMAL ABNORMALITIES OR INHERITED SYNDROMES) OR EPIGENETIC CAUSES (INTRAUTERINE INFECTIONS, TOXINS AND CHEMICALS, MATERNAL DISEASES OF PREGNANCY AFFECTING THE PLACENTA). THE UNDERLYING PATHOPHYSIOLOGICAL PROCESSES THAT OCCUR AT THE CELLULAR AND MOLECULAR LEVEL IN IUGR ARE STILL UNKNOWN. REDUCTION IN THE SUPPLY OF SUBSTRATES THAT ARE NECESSARY FOR NORMAL CELLULAR FUNCTION, AND ALTERATION IN MEDIATOR MOLECULES THAT REGULATE CELLULAR GROWTH AND DIFFERENTIATION, ARE IMPORTANT MECHANISMS. A DECREASE IN GROWTH PROMOTING FACTORS OR AN INCREASE IN GROWTH INHIBITORY FACTORS MAY LEAD TO GROWTH FAILURE. GROWTH FACTORS AND THEIR RECEPTORS ARE EXPRESSED IN THE DEVELOPING EMBRYO (AS EARLY AS THE 1-2-CELL STAGE), PLACENTA AND MATERNAL UTERINE TISSUES, SUGGESTING THAT THESE MOLECULES MAY PLAY A ROLE IN REGULATING NORMAL GROWTH AND DIFFERENTIATION OF THE CONCEPTUS AS WELL AS MATERNAL REPRODUCTIVE TISSUES. THE LOCAL EXPRESSION WITHIN DEVELOPING TISSUES INDICATES THAT THESE FACTORS ACT IN EITHER AUTOCRINE OR PARACRINE MECHANISM. RECENT STUDIES USING GENE TARGETING TO KNOCK OUT ONE ALLELE OF INSULIN-LIKE GROWTH FACTOR II (IGF II) GENE IN MICE WHICH RESULTED IN GROWTH RETARDED PUPS AT BIRTH, STRONGLY SUPPORT THE IMPORTANCE OF LOCAL IGF II IN REGULATING TISSUE GROWTH. FOETAL GROWTH RETARDATION HAS ALSO BEEN INDUCED EXPERIMENTALLY IN SEVERAL SPECIES USING ONE OF THE FOLLOWING METHODS: (I) MATERNAL UNDERNUTRITION, (II) CHRONIC HYPOXIA, (III) PROLONGED REDUCTION IN UTERINE BLOOD FLOW, (IV) REDUCTION IN PLACENTAL SIZE, AND (V) ENDOCRINE ALTERATIONS. THESE MODELS PROVIDE USEFUL INFORMATION ON THE PHYSIOLOGICAL MECHANISMS UNDERLYING A SPECIFIC TYPE OF GROWTH RETARDATION. THESE IN-VIVO MODELS AND IN-VIVO TISSUE CULTURE MODELS CAN NOW BE ANALYSED BY BIOCHEMICAL AND MOLECULAR BIOLOGICAL TECHNIQUES TO UNRAVEL THE BASIC MECHANISMS THAT UNDERLIE FOETAL GROWTH RETARDATION. 1993 5 997 20 CHRONIC STRESS-DRIVEN GLUCOCORTICOID RECEPTOR ACTIVATION PROGRAMS KEY CELL PHENOTYPES AND FUNCTIONAL EPIGENOMIC PATTERNS IN HUMAN FIBROBLASTS. CHRONIC ENVIRONMENTAL STRESS CAN PROFOUNDLY IMPACT CELL AND BODY FUNCTION. ALTHOUGH THE UNDERLYING MECHANISMS ARE POORLY UNDERSTOOD, EPIGENETICS HAS EMERGED AS A KEY LINK BETWEEN ENVIRONMENT AND HEALTH. THE GENOMIC EFFECTS OF STRESS ARE THOUGHT TO BE MEDIATED BY THE ACTION OF GLUCOCORTICOID STRESS HORMONES, PRIMARILY CORTISOL IN HUMANS, WHICH ACT VIA THE GLUCOCORTICOID RECEPTOR (GR). TO DISSECT HOW CHRONIC STRESS-DRIVEN GR ACTIVATION INFLUENCES EPIGENETIC AND CELL STATES, HUMAN FIBROBLASTS UNDERWENT PROLONGED EXPOSURE TO PHYSIOLOGICAL STRESS LEVELS OF CORTISOL AND/OR A SELECTIVE GR ANTAGONIST. CORTISOL WAS FOUND TO DRIVE ROBUST CHANGES IN CELL PROLIFERATION, MIGRATION, AND MORPHOLOGY, WHICH WERE ABROGATED BY CONCOMITANT GR BLOCKADE. THE GR-DRIVEN CELL PHENOTYPES WERE ACCOMPANIED BY WIDESPREAD, YET GENOMIC CONTEXT-DEPENDENT, CHANGES IN DNA METHYLATION AND MRNA EXPRESSION, INCLUDING GENE LOCI WITH KNOWN ROLES IN CELL PROLIFERATION AND MIGRATION. THESE FINDINGS PROVIDE INSIGHTS INTO HOW CHRONIC STRESS-DRIVEN FUNCTIONAL EPIGENOMIC PATTERNS BECOME ESTABLISHED TO SHAPE KEY CELL PHENOTYPES. 2022 6 2183 24 EPIGENETIC MECHANISMS RESPONSIBLE FOR THE TRANSGENERATIONAL INHERITANCE OF INTRAUTERINE GROWTH RESTRICTION PHENOTYPES. A POORLY FUNCTIONING PLACENTA RESULTS IN IMPAIRED EXCHANGES OF OXYGEN, NUTRITION, WASTES AND HORMONES BETWEEN THE MOTHER AND HER FETUS. THIS CAN LEAD TO RESTRICTION OF FETAL GROWTH. THESE GROWTH RESTRICTED BABIES ARE AT INCREASED RISK OF DEVELOPING CHRONIC DISEASES, SUCH AS TYPE-2 DIABETES, HYPERTENSION, AND KIDNEY DISEASE, LATER IN LIFE. ANIMAL STUDIES HAVE SHOWN THAT GROWTH RESTRICTED PHENOTYPES ARE SEX-DEPENDENT AND CAN BE TRANSMITTED TO SUBSEQUENT GENERATIONS THROUGH BOTH THE PATERNAL AND MATERNAL LINEAGES. ALTERED EPIGENETIC MECHANISMS, SPECIFICALLY CHANGES IN DNA METHYLATION, HISTONE MODIFICATIONS, AND NON-CODING RNAS THAT REGULATE EXPRESSION OF GENES THAT ARE IMPORTANT FOR FETAL DEVELOPMENT HAVE BEEN SHOWN TO BE ASSOCIATED WITH THE TRANSMISSION PATTERN OF GROWTH RESTRICTED PHENOTYPES. THIS REVIEW WILL DISCUSS THE SUBSEQUENT HEALTH OUTCOMES IN THE OFFSPRING AFTER GROWTH RESTRICTION AND THE TRANSMISSION PATTERNS OF THESE DISEASES. EVIDENCE OF ALTERED EPIGENETIC MECHANISMS IN ASSOCIATION WITH FETAL GROWTH RESTRICTION WILL ALSO BE REVIEWED. 2022 7 2958 29 GENETIC AND EPIGENETIC INSIGHTS INTO FETAL ALCOHOL SPECTRUM DISORDERS. THE MAGNITUDE OF THE DETRIMENTAL EFFECTS FOLLOWING IN UTERO ALCOHOL EXPOSURE, INCLUDING FETAL ALCOHOL SYNDROME AND OTHER FETAL ALCOHOL SPECTRUM DISORDERS (FASD), IS GLOBALLY UNDERESTIMATED. THE EFFECTS INCLUDE IRREVERSIBLE COGNITIVE AND BEHAVIORAL DISABILITIES AS A RESULT OF ABNORMAL BRAIN DEVELOPMENT, PRE- AND POSTNATAL GROWTH RETARDATION AND FACIAL DYSMORPHISM. PARENTAL ALCOHOL EXPOSURE AND ITS EFFECT ON OFFSPRING HAS BEEN RECOGNIZED FOR CENTURIES, BUT ONLY RECENTLY HAVE WE BEGUN TO GAIN MOLECULAR INSIGHT INTO THE MECHANISMS INVOLVED IN ALCOHOL TERATOGENESIS. GENETIC ATTRIBUTES (SUSCEPTIBILITY AND PROTECTIVE ALLELES) OF THE MOTHER AND THE FETUS CONTRIBUTE TO THE RISK OF DEVELOPING FASD AND SPECIFIC ADDITIONAL ENVIRONMENTAL CONDITIONS, INCLUDING MALNUTRITION, HAVE AN IMPORTANT ROLE. THE SEVERITY OF FASD DEPENDS ON THE LEVEL OF ALCOHOL EXPOSURE, THE DEVELOPMENTAL STAGE AT WHICH EXPOSURE OCCURS AND THE NATURE OF THE EXPOSURE (CHRONIC OR ACUTE), AND ALTHOUGH THE MOST VULNERABLE PERIOD IS DURING THE FIRST TRIMESTER, DAMAGE CAN OCCUR THROUGHOUT GESTATION. PRECONCEPTION ALCOHOL EXPOSURE CAN ALSO HAVE A DETRIMENTAL EFFECT ON THE OFFSPRING. SEVERAL DEVELOPMENTAL PATHWAYS ARE AFFECTED IN FASD, INCLUDING NERVOUS SYSTEM DEVELOPMENT, GROWTH AND REMODELING OF TISSUES, AS WELL AS METABOLIC PATHWAYS THAT REGULATE GLUCOCORTICOID SIGNALING AND BALANCED LEVELS OF RETINOL, INSULIN AND NITRIC OXIDE. A BODY OF KNOWLEDGE HAS ACCUMULATED TO SUPPORT THE ROLE OF ENVIRONMENTALLY INDUCED EPIGENETIC REMODELING DURING GAMETOGENESIS AND AFTER CONCEPTION AS A KEY MECHANISM FOR THE TERATOGENIC EFFECTS OF FASD THAT PERSIST INTO ADULTHOOD. TRANSGENERATIONAL EFFECTS ARE LIKELY TO CONTRIBUTE TO THE GLOBAL BURDEN OF ALCOHOL-RELATED DISEASE. FASD RESULTS IN LIFELONG DISABILITY AND PREVENTATIVE PROGRAMS SHOULD INCLUDE BOTH MATERNAL ALCOHOL ABSTENTION AND PRECONCEPTION ALCOHOL AVOIDANCE. 2010 8 1981 18 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 9 4496 22 MORE THAN GENES: THE ADVANCED FETAL PROGRAMMING HYPOTHESIS. MANY LINES OF DATA, INITIAL EPIDEMIOLOGIC STUDIES AS WELL AS SUBSEQUENT EXTENSIVE EXPERIMENTAL STUDIES, INDICATE THAT EARLY-LIFE EVENTS PLAY A POWERFUL ROLE IN INFLUENCING LATER SUCEPTIBILITY TO CERTAIN CHRONIC DISEASES. SUCH EVENTS MIGHT BE OVER- OR UNDERNUTRITION, EXPOSURE TO ENVIRONMENTAL TOXINS, BUT ALSO CHANGES IN HORMONES, IN PARTICULAR STRESS HORMONES. TYPICALLY, THOSE EVENTS ARE TRIGGERED BY THE ENVIRONMENTAL CHALLENGES OF THE MOTHER. HOWEVER, RECENT STUDIES HAVE SHOWN THAT PATERNAL ENVIRONMENTAL OR NUTRITIONAL FACTORS AFFECT THE PHENOTYPE OF THE OFFSPRING AS WELL. THE MATERNAL AND PATERNAL ENVIRONMENTAL FACTORS ACT ON THE PHENOTYPE OF THE OFFSPRING VIA EPIGENETIC MODIFICATION OF ITS GENOME. THE ADVANCED FETAL PROGRAMMING HYPOTHESIS PROPOSES AN ADDITIONAL NON-ENVIRONMENTALLY DRIVEN MECHANISM: MATERNAL AND ALSO PATERNAL GENES MAY INFLUENCE THE MATURATING SPERM, THE OOCYTE, AND LATER THE EMBRYO/FETUS, LEADING TO THEIR EPIGENETIC ALTERATION. THUS, THE OBSERVED PHENOTYPE OF THE OFFSPRING MAY BE ALTERED BY MATERNAL/PATERNAL GENES INDEPENDENT OF THE FETAL GENOME. MEANWHILE, SEVERAL INDEPENDENT ASSOCIATION STUDIES IN HUMANS DEALING WITH METABOLIC AND NEUROLOGICAL TRAITS ALSO SUGGEST THAT MATERNAL GENES MIGHT AFFECT THE OFFSPRING PHENOTYPE INDEPENDENT OF THE TRANSMISSION OF THAT PARTICULAR GENE TO THE OFFSPRING. CONSIDERING THE IMPLICATIONS OF THIS HYPOTHESIS, SOME CONCLUSIONS DRAWN FROM TRANSGENIC OR KNOCKOUT ANIMAL MODELS AND BASED ON THE CAUSALITY BETWEEN A GENETIC ALTERATION AND A PHENOTYPE, NEED TO BE CHALLENGED. POSSIBLE IMPLICATIONS FOR THE DEVELOPMENT, DIAGNOSTIC AND THERAPY OF HUMAN GENETIC DISEASES HAVE TO BE INVESTIGATED. 2014 10 4767 22 NUCLEAR AND MITOCHONDRIAL DNA ALTERATIONS IN NEWBORNS WITH PRENATAL EXPOSURE TO CIGARETTE SMOKE. NEWBORNS EXPOSED TO MATERNAL CIGARETTE SMOKE (CS) IN UTERO HAVE AN INCREASED RISK OF DEVELOPING CHRONIC DISEASES, CANCER, AND ACQUIRING DECREASED COGNITIVE FUNCTION IN ADULTHOOD. ALTHOUGH THE LITERATURE REPORTS MANY DELETERIOUS EFFECTS ASSOCIATED WITH MATERNAL CIGARETTE SMOKING ON THE FETUS, THE MOLECULAR ALTERATIONS AND MECHANISMS OF ACTION ARE NOT YET CLEAR. SMOKING MAY ACT DIRECTLY ON NUCLEAR DNA BY INDUCING MUTATIONS OR EPIGENETIC MODIFICATIONS. RECENT STUDIES ALSO INDICATE THAT SMOKING MAY ACT ON MITOCHONDRIAL DNA BY INDUCING A CHANGE IN THE NUMBER OF COPIES TO MAKE UP FOR THE DAMAGE CAUSED BY SMOKING ON THE RESPIRATORY CHAIN AND LACK OF ENERGY. IN ADDITION, INDIVIDUAL GENETIC SUSCEPTIBILITY PLAYS A SIGNIFICANT ROLE IN DETERMINING THE EFFECTS OF SMOKING DURING DEVELOPMENT. FURTHERMORE, PRIOR EXPOSURE OF PATERNAL AND MATERNAL GAMETES TO CIGARETTE SMOKE MAY AFFECT THE HEALTH OF THE DEVELOPING INDIVIDUAL, NOT ONLY THE IN UTERO EXPOSURE. THIS REVIEW EXAMINES THE GENETIC AND EPIGENETIC ALTERATIONS IN NUCLEAR AND MITOCHONDRIAL DNA ASSOCIATED WITH SMOKE EXPOSURE DURING THE MOST SENSITIVE PERIODS OF DEVELOPMENT (PRIOR TO CONCEPTION, PRENATAL AND EARLY POSTNATAL) AND ASSESSES HOW SUCH CHANGES MAY HAVE CONSEQUENCES FOR BOTH FETAL GROWTH AND DEVELOPMENT. 2015 11 6729 19 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 12 4125 22 MECHANISMS OF DISEASE: IN UTERO PROGRAMMING IN THE PATHOGENESIS OF HYPERTENSION. NUTRITIONAL AND OTHER ENVIRONMENTAL CUES DURING DEVELOPMENT CAN PERMANENTLY ALTER THE STRUCTURE, HOMEOSTATIC SYSTEMS, AND FUNCTIONS OF THE BODY. THIS PHENOMENON HAS BEEN REFERRED TO AS 'PROGRAMMING'. EPIDEMIOLOGICAL AND ANIMAL STUDIES SHOW THAT PROGRAMMED EFFECTS OPERATE WITHIN THE NORMAL RANGE OF GROWTH AND DEVELOPMENT, AND INFLUENCE THE RISK OF CHRONIC DISEASE IN ADULT LIFE. WE REVIEW THE EVIDENCE THAT THESE EFFECTS INCLUDE REDUCED NEPHRON NUMBER AND COMPENSATORY ADAPTATIONS, WHICH MIGHT LEAD TO HYPERTENSION, AND PERHAPS ACCELERATE THE DECLINE IN RENAL FUNCTION THAT ACCOMPANIES AGING. THESE PROCESSES MIGHT BE EXACERBATED BY PROGRAMMED CHANGES IN VASCULAR STRUCTURE AND FUNCTION, AND ALTERATIONS IN ENDOCRINE AND METABOLIC HOMEOSTASIS. PROGRAMMED EFFECTS MIGHT BE INITIATED AS EARLY AS THE PERICONCEPTUAL PHASE OF DEVELOPMENT, AND COULD INVOLVE EPIGENETIC CHANGES IN GENE EXPRESSION OR ALTERED STEM CELL ALLOCATION. BETTER UNDERSTANDING OF THESE PROCESSES COULD LEAD TO THE DEVELOPMENT OF NOVEL DIAGNOSTIC AND PREVENTIVE MEASURES, AND TO EARLY DETECTION OF AT-RISK INDIVIDUALS. BY MONITORING BLOOD PRESSURE, WEIGHT, AND RENAL FUNCTION IN CHILDREN, IT MIGHT BE POSSIBLE TO REDUCE THE RISK OF CARDIOVASCULAR AND RENAL DISEASE IN LATER LIFE. 2006 13 2274 20 EPIGENETIC REGULATION AND FETAL PROGRAMMING. FETAL PROGRAMMING ENCOMPASSES THE ROLE OF DEVELOPMENTAL PLASTICITY IN RESPONSE TO ENVIRONMENTAL AND NUTRITIONAL SIGNALS DURING EARLY LIFE AND ITS POTENTIAL ADVERSE CONSEQUENCES (RISK OF CARDIOVASCULAR, METABOLIC AND BEHAVIOURAL DISEASES) IN LATER LIFE. THE FIRST STUDIES IN THIS FIELD HIGHLIGHTED AN ASSOCIATION BETWEEN POOR FETAL GROWTH AND CHRONIC ADULT DISEASES. HOWEVER, ENVIRONMENTAL SIGNALS DURING EARLY LIFE MAY LEAD TO ADVERSE LONG-TERM EFFECTS INDEPENDENTLY OF OBVIOUS EFFECTS ON FETAL GROWTH. ADVERSE LONG-TERM EFFECTS REFLECT A MISMATCH BETWEEN EARLY (FETAL AND NEONATAL) ENVIRONMENTAL CONDITIONS AND THE CONDITIONS THAT THE INDIVIDUAL WILL CONFRONT LATER IN LIFE. THE MECHANISMS UNDERLYING THIS RISK REMAIN UNCLEAR. HOWEVER, EXPERIMENTAL DATA IN RODENTS AND RECENT OBSERVATIONS IN HUMANS SUGGEST THAT EPIGENETIC CHANGES IN REGULATORY GENES AND GROWTH-RELATED GENES PLAY A SIGNIFICANT ROLE IN FETAL PROGRAMMING. IMPROVEMENTS IN OUR UNDERSTANDING OF THE BIOCHEMICAL AND MOLECULAR MECHANISMS AT PLAY IN FETAL PROGRAMMING WOULD MAKE IT POSSIBLE TO IDENTIFY BIOMARKERS FOR DETECTING INFANTS AT HIGH RISK OF ADULT-ONSET DISEASES. SUCH IMPROVEMENTS SHOULD ALSO LEAD TO THE DEVELOPMENT OF PREVENTIVE AND THERAPEUTIC STRATEGIES. 2008 14 4788 24 NUTRITION, EPIGENETICS, AND METABOLIC SYNDROME. SIGNIFICANCE: EPIDEMIOLOGICAL AND ANIMAL STUDIES HAVE DEMONSTRATED A CLOSE LINK BETWEEN MATERNAL NUTRITION AND CHRONIC METABOLIC DISEASE IN CHILDREN AND ADULTS. COMPELLING EXPERIMENTAL RESULTS ALSO INDICATE THAT ADVERSE EFFECTS OF INTRAUTERINE GROWTH RESTRICTION ON OFFSPRING CAN BE CARRIED FORWARD TO SUBSEQUENT GENERATIONS THROUGH COVALENT MODIFICATIONS OF DNA AND CORE HISTONES. RECENT ADVANCES: DNA METHYLATION IS CATALYZED BY S-ADENOSYLMETHIONINE-DEPENDENT DNA METHYLTRANSFERASES. METHYLATION, DEMETHYLATION, ACETYLATION, AND DEACETYLATION OF HISTONE PROTEINS ARE PERFORMED BY HISTONE METHYLTRANSFERASE, HISTONE DEMETHYLASE, HISTONE ACETYLTRANSFERASE, AND HISTONE DEACETYLTRANSFERASE, RESPECTIVELY. HISTONE ACTIVITIES ARE ALSO INFLUENCED BY PHOSPHORYLATION, UBIQUITINATION, ADP-RIBOSYLATION, SUMOYLATION, AND GLYCOSYLATION. METABOLISM OF AMINO ACIDS (GLYCINE, HISTIDINE, METHIONINE, AND SERINE) AND VITAMINS (B6, B12, AND FOLATE) PLAYS A KEY ROLE IN PROVISION OF METHYL DONORS FOR DNA AND PROTEIN METHYLATION. CRITICAL ISSUES: DISRUPTION OF EPIGENETIC MECHANISMS CAN RESULT IN OXIDATIVE STRESS, OBESITY, INSULIN RESISTANCE, DIABETES, AND VASCULAR DYSFUNCTION IN ANIMALS AND HUMANS. DESPITE A RECOGNIZED ROLE FOR EPIGENETICS IN FETAL PROGRAMMING OF METABOLIC SYNDROME, RESEARCH ON THERAPIES IS STILL IN ITS INFANCY. POSSIBLE INTERVENTIONS INCLUDE: 1) INHIBITION OF DNA METHYLATION, HISTONE DEACETYLATION, AND MICRORNA EXPRESSION; 2) TARGETING EPIGENETICALLY DISTURBED METABOLIC PATHWAYS; AND 3) DIETARY SUPPLEMENTATION WITH FUNCTIONAL AMINO ACIDS, VITAMINS, AND PHYTOCHEMICALS. FUTURE DIRECTIONS: MUCH WORK IS NEEDED WITH ANIMAL MODELS TO UNDERSTAND THE BASIC MECHANISMS RESPONSIBLE FOR THE ROLES OF SPECIFIC NUTRIENTS IN FETAL AND NEONATAL PROGRAMMING. SUCH NEW KNOWLEDGE IS CRUCIAL TO DESIGN EFFECTIVE THERAPEUTIC STRATEGIES FOR PREVENTING AND TREATING METABOLIC ABNORMALITIES IN OFFSPRING BORN TO MOTHERS WITH A PREVIOUS EXPERIENCE OF MALNUTRITION. 2012 15 3148 27 GLUCOCORTICOID INDUCED LOSS OF OESTROGEN RECEPTOR ALPHA GENE METHYLATION AND RESTORATION OF SENSITIVITY TO FULVESTRANT IN TRIPLE NEGATIVE BREAST CANCER. THE RESPONSE TO PSYCHOLOGICAL STRESS CAN DIFFER DEPENDING ON THE TYPE AND DURATION OF THE STRESSOR. ACUTE STRESS CAN FACILITATE A "FIGHT OR FLIGHT RESPONSE" AND AID SURVIVAL, WHEREAS CHRONIC LONG-TERM STRESS WITH THE PERSISTENT RELEASE OF STRESS HORMONES SUCH AS CORTISOL HAS BEEN SHOWN TO BE DETRIMENTAL TO HEALTH. WE ARE NOW BEGINNING TO UNDERSTAND HOW THIS STRESS HORMONE RESPONSE IMPACTS IMPORTANT PROCESSES SUCH AS DNA REPAIR AND CELL PROLIFERATION PROCESSES IN BREAST CANCER. HOWEVER, IT IS NOT KNOWN WHAT EPIGENETIC CHANGES STRESS HORMONES INDUCE IN BREAST CANCER. EPIGENETIC MECHANISMS INCLUDE MODIFICATION OF DNA AND HISTONES WITHIN CHROMATIN THAT MAY BE INVOLVED IN GOVERNING THE TRANSCRIPTIONAL PROCESSES IN CANCER CELLS IN RESPONSE TO CHANGES BY ENDOGENOUS STRESS HORMONES. THE CONTRIBUTION OF ENDOGENOUS ACUTE OR LONG-TERM EXPOSURE OF GLUCOCORTICOID STRESS HORMONES, AND EXOGENOUS GLUCOCORTICOIDS TO METHYLATION PATTERNS IN BREAST CANCER TISSUES WITH DIFFERENT AETIOLOGIES REMAINS TO BE EVALUATED. IN VITRO AND IN VIVO MODELS WERE DEVELOPED TO INVESTIGATE THE EPIGENETIC MODIFICATIONS AND THEIR CONTRIBUTION TO BREAST CANCER PROGRESSION AND AETIOLOGY. A PANEL OF TRIPLE NEGATIVE BREAST CANCER CELL LINES WERE TREATED WITH THE GLUCOCORTICOID, CORTISOL WHICH RESULTED IN EPIGENETIC ALTERATION CHARACTERISED BY LOSS OF METHYLATION ON PROMOTER REGIONS OF TUMOUR SUPPRESSOR GENES INCLUDING ESR1, AND LOSS OF METHYLATION ON LINE-1 REPETITIVE ELEMENT USED AS A SURROGATE MARKER FOR GLOBAL METHYLATION. THIS WAS VERIFIED IN VIVO IN MDA-MB-231 XENOGRAFTS; THE MODEL VERIFIED THE LOSS OF METHYLATION ON ESR1 PROMOTER, AND SUBSEQUENT INCREASE IN ESR1 EXPRESSION IN PRIMARY TUMOURS IN MICE SUBJECTED TO RESTRAINT STRESS. OUR STUDY HIGHLIGHTS THAT DNA METHYLATION LANDSCAPE IN BREAST CANCER CAN BE ALTERED IN RESPONSE TO STRESS AND GLUCOCORTICOID TREATMENT. 2023 16 684 27 BRAIN STAT5 MODULATES LONG-TERM METABOLIC AND EPIGENETIC CHANGES INDUCED BY PREGNANCY AND LACTATION IN FEMALE MICE. SEVERAL METABOLIC AND BEHAVIORAL ADAPTATIONS THAT EMERGE DURING PREGNANCY REMAIN PRESENT AFTER WEANING. THUS, REPRODUCTIVE EXPERIENCE CAUSES LONG-LASTING METABOLIC PROGRAMMING, PARTICULARLY IN THE BRAIN. HOWEVER, THE ISOLATE EFFECTS OF PREGNANCY OR LACTATION AND THE MOLECULAR MECHANISMS INVOLVED IN THESE LONG-TERM MODIFICATIONS ARE CURRENTLY UNKNOWN. IN THE CURRENT STUDY, WE INVESTIGATED THE ROLE OF BRAIN SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION-5 (STAT5), A KEY TRANSCRIPTION FACTOR RECRUITED BY HORMONES HIGHLY SECRETED DURING GESTATION OR LACTATION, FOR THE LONG-TERM ADAPTATIONS INDUCED BY REPRODUCTIVE EXPERIENCE. IN CONTROL MICE, PREGNANCY FOLLOWED BY LACTATION LED TO INCREASED BODY ADIPOSITY AND REDUCED AMBULATORY ACTIVITY LATER IN LIFE. ADDITIONALLY, PREGNANCY+LACTATION INDUCED LONG-TERM EPIGENETIC MODIFICATIONS IN THE BRAIN: WE OBSERVED UPREGULATION IN HYPOTHALAMIC EXPRESSION OF HISTONE DEACETYLASES AND REDUCED NUMBERS OF NEURONS WITH HISTONE H3 ACETYLATION IN THE PARAVENTRICULAR, ARCUATE, AND VENTROMEDIAL NUCLEI. REMARKABLY, BRAIN-SPECIFIC STAT5 ABLATION PREVENTED ALL METABOLIC AND EPIGENETIC CHANGES OBSERVED IN REPRODUCTIVELY EXPERIENCED CONTROL FEMALE MICE. NONETHELESS, BRAIN-SPECIFIC STAT5 KNOCKOUT (KO) MICE THAT HAD THE EXPERIENCE OF PREGNANCY BUT DID NOT LACTATE SHOWED INCREASED BODY WEIGHT AND REDUCED ENERGY EXPENDITURE LATER IN LIFE, WHEREAS PREGNANCY KO AND PREGNANCY+LACTATION KO MICE EXHIBITED IMPROVED INSULIN SENSITIVITY COMPARED WITH VIRGIN KO MICE. IN SUMMARY, LACTATION IS NECESSARY FOR THE LONG-LASTING METABOLIC EFFECTS OBSERVED IN REPRODUCTIVELY EXPERIENCED FEMALE MICE. IN ADDITION, EPIGENETIC MECHANISMS INVOLVING HISTONE ACETYLATION IN NEURONAL POPULATIONS RELATED TO ENERGY BALANCE REGULATION ARE POSSIBLY ASSOCIATED WITH THESE LONG-TERM CONSEQUENCES. FINALLY, OUR FINDINGS HIGHLIGHTED THE KEY ROLE PLAYED BY BRAIN STAT5 SIGNALING FOR THE CHRONIC METABOLIC AND EPIGENETIC CHANGES INDUCED BY PREGNANCY AND LACTATION. 2019 17 4064 24 MATERNAL AND EARLY-LIFE CIRCADIAN DISRUPTION HAVE LONG-LASTING NEGATIVE CONSEQUENCES ON OFFSPRING DEVELOPMENT AND ADULT BEHAVIOR IN MICE. MODERN LIFE INVOLVES CHRONIC CIRCADIAN DISRUPTION THROUGH ARTIFICIAL LIGHT AND THESE DISRUPTIONS ARE ASSOCIATED WITH NUMEROUS MENTAL AND PHYSICAL HEALTH MALADIES. BECAUSE THE DEVELOPING NERVOUS SYSTEM IS PARTICULARLY VULNERABLE TO PERTURBATION, WE HYPOTHESIZED THAT EARLY-LIFE CIRCADIAN DISRUPTION WOULD NEGATIVELY IMPACT OFFSPRING DEVELOPMENT AND ADULT FUNCTION. PREGNANT MICE WERE SUBJECTED TO CHRONIC CIRCADIAN DISRUPTION FROM THE TIME OF UTERINE IMPLANTATION THROUGH WEANING. TO DISSOCIATE IN UTERO FROM POSTNATAL EFFECTS, A SUBSET OF LITTERS WAS CROSS-FOSTERED AT BIRTH FROM DISRUPTED DAMS TO CONTROL DAMS AND VICE VERSA. POSTNATAL CIRCADIAN DISRUPTION WAS ASSOCIATED WITH REDUCED ADULT BODY MASS, SOCIAL AVOIDANCE, AND HYPERACTIVITY. IN UTERO DISRUPTION RESULTED IN MORE PRONOUNCED SOCIAL AVOIDANCE AND HYPERACTIVITY, PHENOTYPES NOT ABROGATED BY CROSS-FOSTERING TO CONTROL MOTHERS. TO EXAMINE WHETHER CIRCADIAN DISRUPTION AFFECTS DEVELOPMENT BY ACTING AS AN EARLY LIFE STRESSOR, WE EXAMINED BIRTHWEIGHT, LITTER SIZE, MATERNAL CANNIBALISM, AND EPIGENETIC MODIFICATIONS. NONE OF THESE VARIABLES DIFFERED BETWEEN CONTROL AND DISRUPTED DAMS, OR RESEMBLED PATTERNS SEEN FOLLOWING EARLY-LIFE STRESS. OUR FINDINGS INDICATE THAT DEVELOPMENTAL CHRONIC CIRCADIAN DISRUPTION PERMANENTLY AFFECTS SOMATIC AND BEHAVIORAL DEVELOPMENT IN A STAGE-OF-LIFE-DEPENDENT MANNER, INDEPENDENT OF EARLY LIFE STRESS MECHANISMS, UNDERSCORING THE IMPORTANCE OF TEMPORAL STRUCTURE DURING DEVELOPMENT, BOTH IN UTERO AND EARLY POSTNATAL LIFE. 2017 18 291 23 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 19 5661 20 SEXUAL DIMORPHISM IN EPIGENOMIC RESPONSES OF STEM CELLS TO EXTREME FETAL GROWTH. EXTREME FETAL GROWTH IS ASSOCIATED WITH INCREASED SUSCEPTIBILITY TO A RANGE OF ADULT DISEASES THROUGH AN UNKNOWN MECHANISM OF CELLULAR MEMORY. WE TESTED WHETHER HERITABLE EPIGENETIC PROCESSES IN LONG-LIVED CD34(+) HAEMATOPOIETIC STEM/PROGENITOR CELLS SHOWED EVIDENCE FOR RE-PROGRAMMING ASSOCIATED WITH THE EXTREMES OF FETAL GROWTH. HERE WE SHOW THAT BOTH FETAL GROWTH RESTRICTION AND OVER-GROWTH ARE ASSOCIATED WITH GLOBAL SHIFTS TOWARDS DNA HYPERMETHYLATION, TARGETING CIS-REGULATORY ELEMENTS IN PROXIMITY TO GENES INVOLVED IN GLUCOSE HOMEOSTASIS AND STEM CELL FUNCTION. WE FIND A SEXUALLY DIMORPHIC RESPONSE; INTRAUTERINE GROWTH RESTRICTION IS ASSOCIATED WITH SUBSTANTIALLY GREATER EPIGENETIC DYSREGULATION IN MALES, WHEREAS LARGE FOR GESTATIONAL AGE GROWTH PREDOMINANTLY AFFECTS FEMALES. THE FINDINGS ARE CONSISTENT WITH EXTREME FETAL GROWTH INTERACTING WITH VARIABLE FETAL SUSCEPTIBILITY TO INFLUENCE CELLULAR AGEING AND METABOLIC CHARACTERISTICS THROUGH EPIGENETIC MECHANISMS, POTENTIALLY GENERATING BIOMARKERS THAT COULD IDENTIFY INFANTS AT HIGHER RISK FOR CHRONIC DISEASE LATER IN LIFE. 2014 20 1371 23 DEVELOPMENTAL ORIGINS OF HEALTH AND DISEASE: NEW INSIGHTS. EPIDEMIOLOGICAL AND ANIMAL STUDIES SHOW THAT SMALL CHANGES IN THE DEVELOPMENTAL ENVIRONMENT CAN INDUCE PHENOTYPIC CHANGES AFFECTING AN INDIVIDUAL'S RESPONSES TO THEIR LATER ENVIRONMENT. THESE MAY ALTER THE RISK OF CHRONIC DISEASE SUCH AS METABOLIC SYNDROME OR CARDIOVASCULAR DISEASE. RECENT RESEARCH SHOWS THAT ANIMALS EXPOSED TO SUCH A MISMATCH BETWEEN PRENATAL AND POSTNATAL ENVIRONMENT DEVELOP OBESITY, REDUCED ACTIVITY, LEPTIN AND INSULIN RESISTANCE, ELEVATED BLOOD PRESSURE AND VASCULAR ENDOTHELIAL DYSFUNCTION. EPIGENETIC PROCESSES ARE INVOLVED IN SUCH EFFECTS, TARGETED TO PROMOTER REGIONS OF SPECIFIC GENES IN SPECIFIC TISSUES. SUCH FINE CONTROL OF GENE EXPRESSION SUGGESTS THAT THE MECHANISMS HAVE BEEN RETAINED THROUGH EVOLUTION THROUGH THEIR ADAPTIVE ADVANTAGE, RATHER THAN REPRESENTING EXTREME EFFECTS OF DEVELOPMENTAL DISRUPTION AKIN TO TERATOGENESIS. THERE MAY BE ADAPTIVE ADVANTAGE IN A DEVELOPMENTAL CUE INDUCING A PHENOTYPIC CHANGE IN GENERATIONS BEYOND THE IMMEDIATE PREGNANCY, AND A RANGE OF DATA THAT SUPPORT THIS CONCEPT. IN ANIMALS, EPIGENETIC EFFECTS SUCH AS DNA METHYLATION CAN BE PASSED TO SUCCESSIVE GENERATIONS. ENVIRONMENTAL TOXINS, INCLUDING ENDOCRINE DISRUPTORS, MAY INDUCE GREATER RISK OF CHRONIC DISEASE, EVEN AT LOW EXPOSURE LEVELS, IF THEY AFFECT SUCH NORMAL DEVELOPMENTAL EPIGENETIC PROCESSES. APPROPRIATE INTERVENTIONS MAY HAVE LONG-TERM MULTIGENERATIONAL EFFECTS TO REDUCE THE RISK OF CHRONIC DISEASE. 2008