1 2415 109 EPIGENETIC SIGNALING IN PSYCHIATRIC DISORDERS: STRESS AND DEPRESSION. PSYCHIATRIC DISORDERS ARE COMPLEX MULTIFACTORIAL DISORDERS INVOLVING CHRONIC ALTERATIONS IN NEURAL CIRCUIT STRUCTURE AND FUNCTION. WHILE GENETIC FACTORS PLAY A ROLE IN THE ETIOLOGY OF DISORDERS SUCH AS DEPRESSION, ADDICTION, AND SCHIZOPHRENIA, RELATIVELY HIGH RATES OF DISCORDANCE AMONG IDENTICAL TWINS CLEARLY POINT TO THE IMPORTANCE OF ADDITIONAL FACTORS. ENVIRONMENTAL FACTORS, SUCH AS STRESS, PLAY A MAJOR ROLE IN THE PSYCHIATRIC DISORDERS BY INDUCING STABLE CHANGES IN GENE EXPRESSION, NEURAL CIRCUIT FUNCTION, AND ULTIMATELY BEHAVIOR. INSULTS AT THE DEVELOPMENTAL STAGE AND IN ADULTHOOD APPEAR TO INDUCE DISTINCT MALADAPTATIONS. INCREASING EVIDENCE INDICATES THAT THESE SUSTAINED ABNORMALITIES ARE MAINTAINED BY EPIGENETIC MODIFICATIONS IN SPECIFIC BRAIN REGIONS. INDEED, TRANSCRIPTIONAL DYSREGULATION AND ASSOCIATED ABERRANT EPIGENETIC REGULATION IS A UNIFYING THEME IN PSYCHIATRIC DISORDERS. ASPECTS OF DEPRESSION CAN BE MODELED IN ANIMALS BY INDUCING DISEASE-LIKE STATES THROUGH ENVIRONMENTAL MANIPULATIONS, AND THESE STUDIES CAN PROVIDE A MORE GENERAL UNDERSTANDING OF EPIGENETIC MECHANISMS IN PSYCHIATRIC DISORDERS. UNDERSTANDING HOW ENVIRONMENTAL FACTORS RECRUIT THE EPIGENETIC MACHINERY IN ANIMAL MODELS IS PROVIDING NEW INSIGHTS INTO DISEASE MECHANISMS IN HUMANS. 2014 2 2414 96 EPIGENETIC SIGNALING IN PSYCHIATRIC DISORDERS. PSYCHIATRIC DISORDERS ARE COMPLEX MULTIFACTORIAL ILLNESSES INVOLVING CHRONIC ALTERATIONS IN NEURAL CIRCUIT STRUCTURE AND FUNCTION. WHILE GENETIC FACTORS ARE IMPORTANT IN THE ETIOLOGY OF DISORDERS SUCH AS DEPRESSION AND ADDICTION, RELATIVELY HIGH RATES OF DISCORDANCE AMONG IDENTICAL TWINS CLEARLY INDICATE THE IMPORTANCE OF ADDITIONAL MECHANISMS. ENVIRONMENTAL FACTORS SUCH AS STRESS OR PRIOR DRUG EXPOSURE ARE KNOWN TO PLAY A ROLE IN THE ONSET OF THESE ILLNESSES. SUCH EXPOSURE TO ENVIRONMENTAL INSULTS INDUCES STABLE CHANGES IN GENE EXPRESSION, NEURAL CIRCUIT FUNCTION, AND ULTIMATELY BEHAVIOR, AND THESE MALADAPTATIONS APPEAR DISTINCT BETWEEN DEVELOPMENTAL AND ADULT EXPOSURES. INCREASING EVIDENCE INDICATES THAT THESE SUSTAINED ABNORMALITIES ARE MAINTAINED BY EPIGENETIC MODIFICATIONS IN SPECIFIC BRAIN REGIONS. INDEED, TRANSCRIPTIONAL DYSREGULATION AND ASSOCIATED ABERRANT EPIGENETIC REGULATION IS A UNIFYING THEME IN PSYCHIATRIC DISORDERS. ASPECTS OF DEPRESSION AND ADDICTION CAN BE MODELED IN ANIMALS BY INDUCING DISEASE-LIKE STATES THROUGH ENVIRONMENTAL MANIPULATIONS (E.G., CHRONIC STRESS, DRUG ADMINISTRATION). UNDERSTANDING HOW ENVIRONMENTAL FACTORS RECRUIT THE EPIGENETIC MACHINERY IN ANIMAL MODELS REVEALS NEW INSIGHT INTO DISEASE MECHANISMS IN HUMANS. 2014 3 2011 87 EPIGENETIC BASIS OF MENTAL ILLNESS. PSYCHIATRIC DISORDERS ARE COMPLEX MULTIFACTORIAL ILLNESSES INVOLVING CHRONIC ALTERATIONS IN NEURAL CIRCUIT STRUCTURE AND FUNCTION AS WELL AS LIKELY ABNORMALITIES IN GLIAL CELLS. WHILE GENETIC FACTORS ARE IMPORTANT IN THE ETIOLOGY OF MOST MENTAL DISORDERS, THE RELATIVELY HIGH RATES OF DISCORDANCE AMONG IDENTICAL TWINS, PARTICULARLY FOR DEPRESSION AND OTHER STRESS-RELATED SYNDROMES, CLEARLY INDICATE THE IMPORTANCE OF ADDITIONAL MECHANISMS. ENVIRONMENTAL FACTORS SUCH AS STRESS ARE KNOWN TO PLAY A ROLE IN THE ONSET OF THESE ILLNESSES. EXPOSURE TO SUCH ENVIRONMENTAL INSULTS INDUCES STABLE CHANGES IN GENE EXPRESSION, NEURAL CIRCUIT FUNCTION, AND ULTIMATELY BEHAVIOR, AND THESE MALADAPTATIONS APPEAR DISTINCT BETWEEN DEVELOPMENTAL VERSUS ADULT EXPOSURES. INCREASING EVIDENCE INDICATES THAT THESE SUSTAINED ABNORMALITIES ARE MAINTAINED BY EPIGENETIC MODIFICATIONS IN SPECIFIC BRAIN REGIONS. INDEED, TRANSCRIPTIONAL DYSREGULATION AND THE ABERRANT EPIGENETIC REGULATION THAT UNDERLIES THIS DYSREGULATION IS A UNIFYING THEME IN PSYCHIATRIC DISORDERS. HERE, WE PROVIDE A PROGRESS REPORT OF EPIGENETIC STUDIES OF THE THREE MAJOR PSYCHIATRIC SYNDROMES, DEPRESSION, SCHIZOPHRENIA, AND BIPOLAR DISORDER. WE REVIEW THE LITERATURE DERIVED FROM ANIMAL MODELS OF THESE DISORDERS AS WELL AS FROM STUDIES OF POSTMORTEM BRAIN TISSUE FROM HUMAN PATIENTS. WHILE EPIGENETIC STUDIES OF MENTAL ILLNESS REMAIN AT EARLY STAGES, UNDERSTANDING HOW ENVIRONMENTAL FACTORS RECRUIT THE EPIGENETIC MACHINERY WITHIN SPECIFIC BRAIN REGIONS TO CAUSE LASTING CHANGES IN DISEASE SUSCEPTIBILITY AND PATHOPHYSIOLOGY IS REVEALING NEW INSIGHT INTO THE ETIOLOGY AND TREATMENT OF THESE CONDITIONS. 2016 4 2459 22 EPIGENETIC THERAPIES FOR NON-ONCOLOGY INDICATIONS. CHRONIC AND DEGENERATIVE DISORDERS ARE A MAJOR, AND GROWING, HUMAN HEALTH BURDEN, AND CURRENT TREATMENTS ARE IN MANY CASES INADEQUATE OR VERY EXPENSIVE. EPIGENETIC THERAPIES ARE ATTRACTIVE OPTIONS FOR TREATING SUCH DISORDERS BECAUSE THEY MANIPULATE THE PROCESSES THAT MAINTAIN CELLS IN AN ABNORMAL TRANSCRIPTIONAL STATE. THE CHALLENGES LIE IN IDENTIFYING THE MOST APPROPRIATE DISEASES AND THE ENZYMES THAT SHOULD BE TARGETED. THIS REVIEW DESCRIBES THE DIFFERENT APPROACHES THAT CAN BE USED TO ADDRESS THIS PROBLEM, FOCUSING PARTICULARLY ON CNS DISORDERS (ESPECIALLY MENTAL RETARDATION, NEURODEGENERATIVE DISEASE, PSYCHIATRIC DISORDERS AND DRUG ADDICTION), DIABETES AND DIABETIC COMPLICATIONS, AND AUTOIMMUNITY AND INFLAMMATORY DISEASES. 2010 5 6412 33 THE SPECTRUM OF FUNDAMENTAL BASIC SCIENCE DISCOVERIES CONTRIBUTING TO ORGANISMAL AGING. AGING RESEARCH HAS UNDERGONE UNPRECEDENTED ADVANCES AT AN ACCELERATING RATE IN RECENT YEARS, LEADING TO EXCITEMENT IN THE FIELD AS WELL AS OPPORTUNITIES FOR IMAGINATION AND INNOVATION. NOVEL INSIGHTS INDICATE THAT, RATHER THAN RESULTING FROM A PREPROGRAMMED SERIES OF EVENTS, THE AGING PROCESS IS PREDOMINANTLY DRIVEN BY FUNDAMENTAL NON-ADAPTIVE MECHANISMS THAT ARE INTERCONNECTED, LINKED, AND OVERLAP. TO VARYING DEGREES, THESE MECHANISMS ALSO MANIFEST WITH AGING IN BONE WHERE THEY CAUSE SKELETAL FRAGILITY. BECAUSE THESE MECHANISMS OF AGING CAN BE MANIPULATED, IT MIGHT BE POSSIBLE TO SLOW, DELAY, OR ALLEVIATE MULTIPLE AGE-RELATED DISEASES AND THEIR COMPLICATIONS BY TARGETING CONSERVED GENETIC SIGNALING PATHWAYS, CONTROLLED FUNCTIONAL NETWORKS, AND BASIC BIOCHEMICAL PROCESSES. INDEED, FINDINGS IN VARIOUS MAMMALIAN SPECIES SUGGEST THAT TARGETING FUNDAMENTAL AGING MECHANISMS (EG, VIA EITHER LOSS-OF-FUNCTION OR GAIN-OF-FUNCTION MUTATIONS OR ADMINISTRATION OF PHARMACOLOGICAL THERAPIES) CAN EXTEND HEALTHSPAN; IE, THE HEALTHY PERIOD OF LIFE FREE OF CHRONIC DISEASES. IN THIS REVIEW, WE SUMMARIZE THE EVIDENCE SUPPORTING THE ROLE OF THE SPECTRUM OF FUNDAMENTAL BASIC SCIENCE DISCOVERIES CONTRIBUTING TO ORGANISMAL AGING, WITH EMPHASIS ON MAMMALIAN STUDIES AND IN PARTICULAR AGING MECHANISMS IN BONE THAT DRIVE SKELETAL FRAGILITY. THESE MECHANISMS OR AGING HALLMARKS INCLUDE: GENOMIC INSTABILITY, TELOMERE ATTRITION, EPIGENETIC ALTERATIONS, LOSS OF PROTEOSTASIS, DEREGULATED NUTRIENT SENSING, MITOCHONDRIAL DYSFUNCTION, CELLULAR SENESCENCE, STEM CELL EXHAUSTION, AND ALTERED INTERCELLULAR COMMUNICATION. BECAUSE THESE MECHANISMS ARE LINKED, INTERVENTIONS THAT AMELIORATE ONE HALLMARK CAN IN THEORY AMELIORATE OTHERS. IN THE FIELD OF BONE AND MINERAL RESEARCH, CURRENT CHALLENGES INCLUDE DEFINING THE RELATIVE CONTRIBUTIONS OF EACH AGING HALLMARK TO THE NATURAL SKELETAL AGING PROCESS, BETTER UNDERSTANDING THE COMPLEX INTERCONNECTIONS AMONG THE HALLMARKS, AND IDENTIFYING THE MOST EFFECTIVE THERAPEUTIC STRATEGIES TO SAFELY TARGET MULTIPLE HALLMARKS. BASED ON THEIR INTERCONNECTIONS, IT MAY BE FEASIBLE TO SIMULTANEOUSLY INTERFERE WITH SEVERAL FUNDAMENTAL AGING MECHANISMS TO ALLEVIATE A WIDE SPECTRUM OF AGE-RELATED CHRONIC DISEASES, INCLUDING OSTEOPOROSIS. (C) 2018 AMERICAN SOCIETY FOR BONE AND MINERAL RESEARCH. 2018 6 2612 28 EPIGENETICS: DECIPHERING HOW ENVIRONMENTAL FACTORS MAY MODIFY AUTOIMMUNE TYPE 1 DIABETES. TYPE 1 DIABETES (T1D) IS AN AUTOIMMUNE DISEASE THAT HAS INCREASED TWO- TO THREEFOLD OVER THE PAST HALF CENTURY BY AS YET UNKNOWN MEANS. IT IS GENERALLY ACCEPTED THAT T1D IS THE RESULT OF GENE-ENVIRONMENT INTERACTIONS, BUT SUCH RAPID INCREASES IN INCIDENCE ARE NOT EXPLAINED BY MENDELIAN INHERITANCE. THERE HAVE BEEN NUMEROUS ADVANCES IN OUR KNOWLEDGE OF THE PATHOGENESIS OF T1D. INDEED, THERE HAS BEEN A LARGE NUMBER OF GENES IDENTIFIED THAT CONTRIBUTE TO RISK FOR THIS DISEASE AND SEVERAL ENVIRONMENTAL FACTORS HAVE BEEN PROPOSED. THE COMPLEXITY OF SUCH INTERACTIONS IS YET TO BE UNDERSTOOD FOR ANY MAJOR CHRONIC DISEASE. EPIGENETIC REGULATION IS ONE WAY TO EXPLAIN THE RAPID INCREASE IN INCIDENCE AND COULD BE A CENTRAL MECHANISM BY WHICH ENVIRONMENTAL FACTORS INFLUENCE DEVELOPMENT OF DIABETES. HOWEVER, THERE IS REMARKABLY LITTLE KNOWN ABOUT THE CONTRIBUTION OF EPIGENETICS TO T1D PATHOGENESIS. HERE WE SPECULATE ON VARIOUS CANDIDATE PROCESSES AND MOLECULES OF THE IMMUNE AND ENDOCRINE SYSTEMS THAT COULD MODIFY RISK FOR T1D THROUGH EPIGENETIC REGULATION. 2009 7 225 35 ACUTE STRESS-INDUCED EPIGENETIC MODULATIONS AND THEIR POTENTIAL PROTECTIVE ROLE TOWARD DEPRESSION. PSYCHIATRIC DISORDERS ENTAIL MALADAPTIVE PROCESSES IMPAIRING INDIVIDUALS' ABILITY TO APPROPRIATELY INTERFACE WITH ENVIRONMENT. AMONG THEM, DEPRESSION IS CHARACTERIZED BY DIVERSE DEBILITATING SYMPTOMS INCLUDING HOPELESSNESS AND ANHEDONIA, DRAMATICALLY IMPACTING THE PROPENSITY TO LIVE A SOCIAL AND ACTIVE LIFE AND SERIOUSLY AFFECTING WORKING CAPABILITY. RELEVANTLY, BESIDES GENETIC PREDISPOSITION, FOREMOST RISK FACTORS ARE STRESS-RELATED, SUCH AS EXPERIENCING CHRONIC PSYCHOSOCIAL STRESS-INCLUDING BULLYING, MOBBING AND ABUSE-, AND UNDERGOING ECONOMIC CRISIS OR CHRONIC ILLNESSES. IN THE LAST FEW YEARS THE FIELD OF EPIGENETICS PROMISED TO UNDERSTAND CORE MECHANISMS OF GENE-ENVIRONMENT CROSSTALK, CONTRIBUTING TO GET INTO PATHOGENIC PROCESSES OF MANY DISORDERS HIGHLY INFLUENCED BY STRESSFUL LIFE CONDITIONS. HOWEVER, STILL VERY LITTLE IS KNOWN ABOUT MECHANISMS THAT TUNE GENE EXPRESSION TO ADAPT TO THE EXTERNAL MILIEU. IN THIS PERSPECTIVE ARTICLE, WE DISCUSS A SET OF PROTECTIVE, FUNCTIONALLY CONVERGENT EPIGENETIC PROCESSES INDUCED BY ACUTE STRESS IN THE RODENT HIPPOCAMPUS AND DEVOTED TO THE NEGATIVE MODULATION OF STRESS-INDUCED IMMEDIATE EARLY GENES (IEGS) TRANSCRIPTION, HINDERING STRESS-DRIVEN MORPHOSTRUCTURAL MODIFICATIONS OF CORTICOLIMBIC CIRCUITRY. WE ALSO SUGGEST THAT CHRONIC STRESS DAMAGING PROTECTIVE EPIGENETIC MECHANISMS, COULD BIAS THE FUNCTIONAL TRAJECTORY OF STRESS-INDUCED NEURONAL MORPHOSTRUCTURAL MODIFICATION FROM ADAPTIVE TO MALADAPTIVE, CONTRIBUTING TO THE ONSET OF DEPRESSION IN VULNERABLE INDIVIDUALS. A BETTER UNDERSTANDING OF THE EPIGENETIC RESPONSE TO STRESS WILL BE PIVOTAL TO NEW AVENUES OF THERAPEUTIC INTERVENTION TO TREAT DEPRESSION, ESPECIALLY IN LIGHT OF LIMITED EFFICACY OF AVAILABLE ANTIDEPRESSANT DRUGS. 2018 8 5280 24 PROMOTING SYMPATHOVAGAL BALANCE IN MULTIPLE SCLEROSIS; PHARMACOLOGICAL, NON-PHARMACOLOGICAL, AND SURGICAL STRATEGIES. ACCUMULATED EVIDENCE SUGGESTS THAT CARDIOVASCULAR AUTONOMIC NERVOUS SYSTEM (ANS) DYSFUNCTION MAY BE THE UNDERLYING CAUSE OF MANY MS CLINICAL PRESENTATIONS, INCLUDING NEURODEGENERATION AND REDUCED RESPONSE TO IMMUNOMODULATORY THERAPIES, DEPRESSION, FATIGUE AND SLEEP DISORDERS, MIGRAINE, OSTEOPOROSIS, AND CHRONIC CEREBROSPINAL VENOUS INSUFFICIENCY, THE NEWER MS VASCULAR ETIOLOGY. WE HAVE RECENTLY DESCRIBED THE GENETIC, EPIGENETIC, AND ENVIRONMENTAL FACTORS WITH THE POTENTIAL INFLUENCING ANS ACTIVITY, AND THE INTERACTIONS AMONG THESE FACTORS. THIS REVIEW EXPANDS UPON PREVIOUS ONES, DESCRIBING THE PHARMACOLOGICAL, NON-PHARMACOLOGICAL, AND SURGICAL STRATEGIES THAT COULD BE ADOPTED TO PREVENT AND MINIMIZE THE DETERIORATION IN ANS FUNCTION, PROMOTING A STATE OF SYMPATHOVAGAL BALANCE. HOWEVER, THESE STRATEGIES SHOULD NOT BE APPLIED AS "ONE SIZE FITS ALL", BUT SHOULD TAKE INTO ACCOUNT THE NATURE AND THE DEGREE OF ANS DYSFUNCTION. THESE STRATEGIES WOULD BE EFFECTIVE IN IMPROVING ANS FUNCTION NOT ONLY IN MS, BUT ALSO IN OTHER AUTOIMMUNE AND NEURODEGENERATIVE DISEASES, WHERE THE DYSFUNCTION OF THIS SYSTEM PLAYS A ROLE. 2016 9 5829 24 STRESS, PSYCHIATRIC DISORDERS, MOLECULAR TARGETS, AND MORE. MENTAL HEALTH IS CENTRAL TO NORMAL HEALTH OUTCOMES. A WIDELY ACCEPTED THEORY IS THAT CHRONIC PERSISTENT STRESS DURING ADULTHOOD AS WELL AS DURING EARLY LIFE TRIGGERS ONSET OF NEUROPSYCHIATRIC AILMENTS. HOWEVER, QUESTIONS RELATED TO HOW THAT OCCURS, AND WHY ARE SOME INDIVIDUALS RESISTANT TO STRESS WHILE OTHERS ARE NOT, REMAIN UNANSWERED. AN INTEGRATED, MULTISYSTEMIC STRESS RESPONSE INVOLVING NEUROINFLAMMATORY, NEUROENDOCRINE, EPIGENETIC AND METABOLIC CASCADES HAVE BEEN SUGGESTED TO HAVE CAUSATIVE LINKS. SEVERAL THEORIES HAVE BEEN PROPOSED OVER THE YEARS TO CONCEPTUALIZE THIS LINK INCLUDING THE CYTOKINE HYPOTHESIS, THE ENDOCRINE HYPOTHESIS, THE OXIDATIVE STRESS HYPOTHESIS AND THE OXIDO-NEUROINFLAMMATION HYPOTHESIS. THE DATA DISCUSSED IN THIS REVIEW DESCRIBES POTENTIAL BIOCHEMICAL BASIS OF THE LINK BETWEEN STRESS, AND STRESS-INDUCED NEURONAL, BEHAVIORAL AND EMOTIONAL DEFICITS, PROVIDING INSIGHTS INTO POTENTIALLY NOVEL DRUG TARGETS. 2019 10 6414 44 THE STRESSED SYNAPSE 2.0: PATHOPHYSIOLOGICAL MECHANISMS IN STRESS-RELATED NEUROPSYCHIATRIC DISORDERS. STRESS IS A PRIMARY RISK FACTOR FOR SEVERAL NEUROPSYCHIATRIC DISORDERS. EVIDENCE FROM PRECLINICAL MODELS AND CLINICAL STUDIES OF DEPRESSION HAVE REVEALED AN ARRAY OF STRUCTURAL AND FUNCTIONAL MALADAPTIVE CHANGES, WHEREBY ADVERSE ENVIRONMENTAL FACTORS SHAPE THE BRAIN. THESE CHANGES, OBSERVED FROM THE MOLECULAR AND TRANSCRIPTIONAL LEVELS THROUGH TO LARGE-SCALE BRAIN NETWORKS, TO THE BEHAVIOURS REVEAL A COMPLEX MATRIX OF INTERRELATED PATHOPHYSIOLOGICAL PROCESSES THAT DIFFER BETWEEN SEXES, PROVIDING INSIGHT INTO THE POTENTIAL UNDERPINNINGS OF THE SEX BIAS OF NEUROPSYCHIATRIC DISORDERS. ALTHOUGH MANY PRECLINICAL STUDIES USE CHRONIC STRESS PROTOCOLS, LONG-TERM CHANGES ARE ALSO INDUCED BY ACUTE EXPOSURE TO TRAUMATIC STRESS, OPENING A PATH TO IDENTIFY DETERMINANTS OF RESILIENT VERSUS SUSCEPTIBLE RESPONSES TO BOTH ACUTE AND CHRONIC STRESS. EPIGENETIC REGULATION OF GENE EXPRESSION HAS EMERGED AS A KEY PLAYER UNDERLYING THE PERSISTENT IMPACT OF STRESS ON THE BRAIN. INDEED, HISTONE MODIFICATION, DNA METHYLATION AND MICRORNAS ARE CLOSELY INVOLVED IN MANY ASPECTS OF THE STRESS RESPONSE AND REVEAL THE GLUTAMATE SYSTEM AS A KEY PLAYER. THE SUCCESS OF KETAMINE HAS STIMULATED A WHOLE LINE OF RESEARCH AND DEVELOPMENT ON DRUGS DIRECTLY OR INDIRECTLY TARGETING GLUTAMATE FUNCTION. HOWEVER, THE CHALLENGE OF TRANSLATING THE EMERGING UNDERSTANDING OF STRESS PATHOPHYSIOLOGY INTO EFFECTIVE CLINICAL TREATMENTS REMAINS A MAJOR CHALLENGE. 2022 11 6184 43 THE IMPACT OF ENVIRONMENTAL FACTORS IN SEVERE PSYCHIATRIC DISORDERS. DURING THE LAST DECADES, SCHIZOPHRENIA HAS BEEN REGARDED AS A DEVELOPMENTAL DISORDER. THE NEURODEVELOPMENTAL HYPOTHESIS PROPOSES SCHIZOPHRENIA TO BE RELATED TO GENETIC AND ENVIRONMENTAL FACTORS LEADING TO ABNORMAL BRAIN DEVELOPMENT DURING THE PRE- OR POSTNATAL PERIOD. FIRST DISEASE SYMPTOMS APPEAR IN EARLY ADULTHOOD DURING THE SYNAPTIC PRUNING AND MYELINATION PROCESS. META-ANALYSES OF STRUCTURAL MRI STUDIES REVEALING HIPPOCAMPAL VOLUME DEFICITS IN FIRST-EPISODE PATIENTS AND IN THE LONGITUDINAL DISEASE COURSE CONFIRM THIS HYPOTHESIS. APART FROM THE INFLUENCE OF RISK GENES IN SEVERE PSYCHIATRIC DISORDERS, ENVIRONMENTAL FACTORS MAY ALSO IMPACT BRAIN DEVELOPMENT DURING THE PERINATAL PERIOD. SEVERAL ENVIRONMENTAL FACTORS SUCH AS ANTENATAL MATERNAL VIRUS INFECTIONS, OBSTETRIC COMPLICATIONS ENTAILING HYPOXIA AS COMMON FACTOR OR STRESS DURING NEURODEVELOPMENT HAVE BEEN IDENTIFIED TO PLAY A ROLE IN SCHIZOPHRENIA AND BIPOLAR DISORDER, POSSIBLY CONTRIBUTING TO SMALLER HIPPOCAMPAL VOLUMES. IN MAJOR DEPRESSION, PSYCHOSOCIAL STRESS DURING THE PERINATAL PERIOD OR IN ADULTHOOD IS AN IMPORTANT TRIGGER. IN ANIMAL STUDIES, CHRONIC STRESS OR REPEATED ADMINISTRATION OF GLUCOCORTICOIDS HAVE BEEN SHOWN TO INDUCE DEGENERATION OF GLUCOCORTICOID-SENSITIVE HIPPOCAMPAL NEURONS AND MAY CONTRIBUTE TO THE PATHOPHYSIOLOGY OF AFFECTIVE DISORDERS. EPIGENETIC MECHANISMS ALTERING THE CHROMATIN STRUCTURE SUCH AS HISTONE ACETYLATION AND DNA METHYLATION MAY MEDIATE EFFECTS OF ENVIRONMENTAL FACTORS TO TRANSCRIPTIONAL REGULATION OF SPECIFIC GENES AND BE A PROMINENT FACTOR IN GENE-ENVIRONMENTAL INTERACTION. IN ANIMAL MODELS, GENE-ENVIRONMENTAL INTERACTION SHOULD BE INVESTIGATED MORE INTENSELY TO UNRAVEL PATHOPHYSIOLOGICAL MECHANISMS. THESE FINDINGS MAY LEAD TO NEW THERAPEUTIC STRATEGIES INFLUENCING EPIGENETIC TARGETS IN SEVERE PSYCHIATRIC DISORDERS. 2014 12 1329 33 DEPRESSION ASSOCIATED WITH DIABETES: FROM PATHOPHYSIOLOGY TO TREATMENT. DIABETES IS A CHRONIC AND PROGRESSIVE SYNDROME COMMONLY ASSOCIATED WITH SEVERAL NEUROPSYCHIATRIC COMORBITIES, OF WHICH DEPRESSION IS THE MOST STUDIED. THE PREVALENCE OF DEPRESSION IS ABOUT TWO OR THREE TIMES HIGHER IN DIABETIC PATIENTS COMPARED TO THE GENERAL POPULATION. IT IS BELIEVED THAT THE DIABETES - DEPRESSION RELATION MAY BE BIDIRECTIONAL, I.E., THE DEPRESSION CAN LEAD TO DIABETES AND CONVERSELY DIABETES COULD FACILITATE THE EMERGENCE OF DEPRESSION. DEPRESSION IS ONE OF THE MOST NEGLECTED SYMPTOMS IN DIABETIC PATIENTS AND IS DIRECTLY LINKED WITH LOWERING OF QUALITY OF LIFE. THE TREATMENT OF DEPRESSION IN THESE PATIENTS IS STILL QUITE INEFFECTIVE AND IN MANY CASES TREATMENTREFRACTORY. FURTHERMORE, SOME OF THE FIRST CHOICE DRUGS USED TO TREAT THE DEPRESSION AFFECT THE BLOOD GLUCOSE CONTROL, AGGRAVATING THE HYPERGLYCEMIC STATE. THESE ISSUES UNDERSCORE THE URGENCY IN STUDIES SEARCHING FOR NEW PHARMACOLOGICAL TARGETS FOR THE TREATMENT OF DEPRESSION ASSOCIATED WITH DIABETES. FOR THIS, A BETTER UNDERSTANDING OF THE PATHOPHYSIOLOGY THAT RELATES THIS COMORBIDITY BECOMES CRITICAL. IN THIS RESPECT, THIS REVIEW WILL FOCUS ON SOME HYPOTHESES THAT HAVE BEEN PROPOSED TO EXPLAIN THE MECHANISMS UNDERLYING DEPRESSION ASSOCIATED WITH DIABETES, HIGHLIGHTING THE TREATMENT OPTIONS CURRENTLY AVAILABLE AND THEIR LIMITATIONS. AMONG THESE HYPOTHESES, WE WILL POINT OUT THE HYPERGLYCEMIA AS A PRIMARY METABOLIC CAUSE OF THE DEPRESSION DEVELOPMENT, THE INVOLVEMENT OF THE DYSREGULATION OF HYPOTHALAMIC PITUITARY-ADRENAL (HPA) AXIS AND OF NEUROTRANSMITTER SYSTEMS, SPECIALLY MONOAMINERGIC SYSTEM. BESIDES, THE ROLE OF OXIDATIVE STRESS, NEUROINFLAMMATION AND CELL DEATH, ESPECIALLY IN HIPPOCAMPUS AND PREFRONTAL CORTEX, BRAIN AREAS IMPORTANT FOR THE MEDIATION AND MODULATION OF EMOTIONAL BEHAVIOR WILL ALSO BE DISCUSSED. FINALLY, WE WILL BRING UP THE INFLUENCE OF THE EPIGENETIC REGULATION WITH RESPECT TO NEUROPSYCHIATRIC DISORDERS. 2016 13 5315 33 PSYCHOLOGICAL STRESS IN CHILDHOOD AND SUSCEPTIBILITY TO THE CHRONIC DISEASES OF AGING: MOVING TOWARD A MODEL OF BEHAVIORAL AND BIOLOGICAL MECHANISMS. AMONG PEOPLE EXPOSED TO MAJOR PSYCHOLOGICAL STRESSORS IN EARLY LIFE, THERE ARE ELEVATED RATES OF MORBIDITY AND MORTALITY FROM CHRONIC DISEASES OF AGING. THE MOST COMPELLING DATA COME FROM STUDIES OF CHILDREN RAISED IN POVERTY OR MALTREATED BY THEIR PARENTS, WHO SHOW HEIGHTENED VULNERABILITY TO VASCULAR DISEASE, AUTOIMMUNE DISORDERS, AND PREMATURE MORTALITY. THESE FINDINGS RAISE CHALLENGING THEORETICAL QUESTIONS. HOW DOES CHILDHOOD STRESS GET UNDER THE SKIN, AT THE MOLECULAR LEVEL, TO AFFECT RISK FOR LATER DISEASES? AND HOW DOES IT INCUBATE THERE, GIVING RISE TO DISEASES SEVERAL DECADES LATER? HERE WE PRESENT A BIOLOGICAL EMBEDDING MODEL, WHICH ATTEMPTS TO ADDRESS THESE QUESTIONS BY SYNTHESIZING KNOWLEDGE ACROSS SEVERAL BEHAVIORAL AND BIOMEDICAL LITERATURES. THIS MODEL MAINTAINS THAT CHILDHOOD STRESS GETS "PROGRAMMED" INTO MACROPHAGES THROUGH EPIGENETIC MARKINGS, POSTTRANSLATIONAL MODIFICATIONS, AND TISSUE REMODELING. AS A CONSEQUENCE THESE CELLS ARE ENDOWED WITH PROINFLAMMATORY TENDENCIES, MANIFEST IN EXAGGERATED CYTOKINE RESPONSES TO CHALLENGE AND DECREASED SENSITIVITY TO INHIBITORY HORMONAL SIGNALS. THE MODEL GOES ON TO PROPOSE THAT OVER THE LIFE COURSE, THESE PROINFLAMMATORY TENDENCIES ARE EXACERBATED BY BEHAVIORAL PROCLIVITIES AND HORMONAL DYSREGULATION, THEMSELVES THE PRODUCTS OF EXPOSURE TO EARLY STRESS. BEHAVIORALLY, THE MODEL POSITS THAT CHILDHOOD STRESS GIVES RISE TO EXCESSIVE THREAT VIGILANCE, MISTRUST OF OTHERS, POOR SOCIAL RELATIONSHIPS, IMPAIRED SELF-REGULATION, AND UNHEALTHY LIFESTYLE CHOICES. HORMONALLY, EARLY STRESS CONFERS ALTERED PATTERNS OF ENDOCRINE AND AUTONOMIC DISCHARGE. THIS MILIEU AMPLIFIES THE PROINFLAMMATORY ENVIRONMENT ALREADY INSTANTIATED BY MACROPHAGES. ACTING IN CONCERT WITH OTHER EXPOSURES AND GENETIC LIABILITIES, THE RESULTING INFLAMMATION DRIVES FORWARD PATHOGENIC MECHANISMS THAT ULTIMATELY FOSTER CHRONIC DISEASE. 2011 14 2572 26 EPIGENETICS OF DEPRESSION. MAJOR DEPRESSIVE DISORDER (MDD) IS A LEADING CAUSE OF DISABILITY WORLDWIDE AND IS ASSOCIATED WITH POOR PSYCHOLOGICAL, MEDICAL, AND SOCIOECONOMIC OUTCOMES. ALTHOUGH MUCH HAS BEEN LEARNED ABOUT THE ETIOLOGY AND TREATMENT OPTIONS OF MDD OVER THE PAST DECADE, THERE REMAIN UNANSWERED QUESTIONS THAT POSE CHALLENGES TO IMPROVING ACUTE AND CHRONIC OUTCOMES FOR THOSE WITH MDD. MDD IS A CLINICALLY HETEROGENEOUS DISORDER. GENETIC STUDIES TO DATE HAVE INDICATED A NUMBER OF GENES, INCLUDING TRANSPORTERS, NEUROTRANSMITTERS, NEUROTROPHINS, AND THEIR ASSOCIATED SIGNALING NETWORKS THAT MAY PREDISPOSE INDIVIDUALS TO MDD AND MAY ALSO PREDICT TREATMENT OUTCOMES. HOWEVER, TWIN STUDIES INDICATE THAT GENES ACCOUNT FOR ONLY A SMALL DEGREE OF THE VARIATION IN MDD. THUS, OTHER MECHANISMS, THROUGH EPIGENETIC MARKS, MAY ACT TO FORM A MOLECULAR MEMORY OF PREVIOUS GENE-TO-ENVIRONMENT INTERACTIONS AND TO ESTABLISH VULNERABILITIES (OR, CONVERSELY, RESISTANCE) TO MDD. CURRENT EVIDENCE SUPPORTS A ROLE FOR PRE-, PERI-, AND EARLY POSTNATAL ADVERSITIES AND STRESSFUL LIFE EVENTS INTO ADULTHOOD AFFECTING EPIGENETIC PATTERNS, PROVIDING A MECHANISTIC FOUNDATION TO DEVELOP EPIGENETIC MARKS AS BIOMARKERS FOR MDD. THIS REVIEW PRESENTS THE EVIDENCE SUPPORTING A ROLE FOR EPIGENETIC EFFECTS IN MDD AND IN TREATMENT RESPONSE. WE ALSO DISCUSS THE CONTROVERSY BEHIND MODULATING EPIGENETIC MECHANISMS IN LONG-TERM ANTIDEPRESSANT PHARMACOTHERAPY. 2014 15 2226 38 EPIGENETIC MODIFICATIONS INDUCED BY NUTRIENTS IN EARLY LIFE PHASES: GENDER DIFFERENCES IN METABOLIC ALTERATION IN ADULTHOOD. METABOLIC CHRONIC DISEASES, ALSO NAMED NONCOMMUNICABLE DISEASES (NCDS), ARE CONSIDERED MULTIFACTORIAL PATHOLOGIES, WHICH ARE DRAMATICALLY INCREASED DURING THE LAST DECADES. NONCOMMUNICABLE DISEASES SUCH AS CARDIOVASCULAR DISEASES, OBESITY, DIABETES MELLITUS, CANCERS, AND CHRONIC RESPIRATORY DISEASES MARKEDLY INCREASE MORBIDITY, MORTALITY, AND SOCIOECONOMIC COSTS. MOREOVER, NCDS INDUCE SEVERAL AND COMPLEX CLINICAL MANIFESTATIONS THAT LEAD TO A GRADUAL DETERIORATION OF HEALTH STATUS AND QUALITY OF LIFE OF AFFECTED INDIVIDUALS. MULTIPLE FACTORS ARE INVOLVED IN THE DEVELOPMENT AND PROGRESSION OF THESE DISEASES SUCH AS SEDENTARY BEHAVIOR, SMOKING, POLLUTION, AND UNHEALTHY DIET. INDEED, NUTRITION HAS A PIVOTAL ROLE IN MAINTAINING HEALTH, AND DIETARY IMBALANCES REPRESENT MAJOR DETERMINANTS FAVORING CHRONIC DISEASES THROUGH METABOLIC HOMEOSTASIS ALTERATIONS. IN PARTICULAR, IT APPEARS THAT SPECIFIC NUTRIENTS AND ADEQUATE NUTRITION ARE IMPORTANT IN ALL PERIODS OF LIFE, BUT THEY ARE ESSENTIAL DURING SPECIFIC TIMES IN EARLY LIFE SUCH AS PRENATAL AND POSTNATAL PHASES. INDEED, EPIDEMIOLOGIC AND EXPERIMENTAL STUDIES REPORT THE DELETERIOUS EFFECTS OF AN INCORRECT NUTRITION ON HEALTH STATUS SEVERAL DECADES LATER IN LIFE. DURING THE LAST DECADE, A GROWING INTEREST ON THE POSSIBLE ROLE OF EPIGENETIC MECHANISMS AS LINK BETWEEN NUTRITIONAL IMBALANCES AND NCDS DEVELOPMENT HAS BEEN OBSERVED. FINALLY, BECAUSE OF THE PIVOTAL ROLE OF THE HORMONES IN FAT, CARBOHYDRATE, AND PROTEIN METABOLISM REGULATION THROUGHOUT LIFE, IT IS EXPECTED THAT ANY HORMONAL MODIFICATION OF THESE PROCESSES CAN IMBALANCE METABOLISM AND FAT STORAGE. THEREFORE, A PARTICULAR INTEREST TO SEVERAL CHEMICALS ABLE TO ACT AS ENDOCRINE DISRUPTORS HAS BEEN RECENTLY DEVELOPED. IN THIS REVIEW, WE WILL PROVIDE AN OVERVIEW AND DISCUSS THE EPIGENETIC ROLE OF SOME SPECIFIC NUTRIENTS AND CHEMICALS IN THE MODULATION OF PHYSIOLOGICAL AND PATHOLOGICAL MECHANISMS. 2019 16 676 28 BRAIN AGING: A IANUS-FACED PLAYER BETWEEN HEALTH AND NEURODEGENERATION. NEURODEGENERATIVE DISEASES ARE INCURABLE DEBILITATING DISORDERS CHARACTERIZED BY STRUCTURAL AND FUNCTIONAL NEURONAL LOSS. APPROXIMATELY 30 MILLION PEOPLE ARE AFFECTED WORLDWIDE, AND THIS NUMBER IS PREDICTED TO REACH MORE THAN 150 MILLION BY 2050. NEURODEGENERATIVE DISORDERS INCLUDE ALZHEIMER'S, PARKINSON'S, AND PRION DISEASES AMONG OTHERS. THESE DISORDERS ARE CHARACTERIZED BY THE ACCUMULATION OF AGGREGATING PROTEINS FORMING AMYLOID, RESPONSIBLE FOR THE DISEASE-ASSOCIATED PATHOLOGICAL LESIONS. THE AGGREGATION OF AMYLOIDOGENIC PROTEINS CAN RESULT EITHER IN GAINING OF TOXIC FUNCTIONS, DERIVED FROM THE DAMAGE PROVOKED BY THESE DEPOSITS IN AFFECTED TISSUE, OR IN A LOSS OF FUNCTIONS, DUE TO THE SEQUESTRATION AND THE CONSEQUENT INABILITY OF THE AGGREGATING PROTEIN TO ENSURE ITS PHYSIOLOGICAL ROLE. WHILE IT IS WIDELY ACCEPTED THAT AGING REPRESENTS THE MAIN RISK FACTOR FOR NEURODEGENERATION, THERE IS STILL NO CLEAR CUT-OFF LINE BETWEEN THE TWO CONDITIONS. INDEED, MANY OF THE PATHWAYS THAT ARE COMMONLY ALTERED IN NEURODEGENERATION-MISFOLDED PROTEIN ACCUMULATION, CHRONIC INFLAMMATION, MITOCHONDRIAL DYSFUNCTION, IMPAIRED IRON HOMEOSTASIS, EPIGENETIC MODIFICATIONS-HAVE BEEN OFTEN CORRELATED ALSO WITH HEALTHY AGING. THIS OVERLAP COULD BE EXPLAINED BY THE FACT THAT THE CONTINUOUS ACCUMULATION OF CELLULAR DAMAGES, TOGETHER WITH A PROGRESSIVE DECLINE IN METABOLIC EFFICIENCY DURING AGING, MAKES THE NEURONS MORE VULNERABLE TO TOXIC INJURIES. WHEN A GIVEN THRESHOLD IS EXCEEDED, ALL THESE ALTERATIONS MIGHT GIVE RISE TO PATHOLOGICAL PHENOTYPES THAT ULTIMATELY LEAD TO NEURODEGENERATION. 2020 17 4914 25 PAIN VULNERABILITY: A NEUROBIOLOGICAL PERSPECTIVE. THERE ARE MANY KNOWN RISK FACTORS FOR CHRONIC PAIN CONDITIONS, YET THE BIOLOGICAL UNDERPINNINGS THAT LINK THESE FACTORS TO ABNORMAL PROCESSING OF PAINFUL SIGNALS ARE ONLY JUST BEGINNING TO BE EXPLORED. THIS REVIEW WILL DISCUSS THE POTENTIAL MECHANISMS THAT HAVE BEEN PROPOSED TO UNDERLIE VULNERABILITY AND RESILIENCE TOWARD DEVELOPING CHRONIC PAIN. PARTICULAR FOCUS WILL BE GIVEN TO GENETIC AND EPIGENETIC PROCESSES, PRIMING EFFECTS ON A CELLULAR LEVEL, AND ALTERATIONS IN BRAIN NETWORKS CONCERNED WITH REWARD, MOTIVATION/LEARNING AND DESCENDING MODULATORY CONTROL. ALTHOUGH RESEARCH IN THIS AREA IS STILL IN ITS INFANCY, A BETTER UNDERSTANDING OF HOW PAIN VULNERABILITY EMERGES HAS THE POTENTIAL TO HELP IDENTIFY INDIVIDUALS AT RISK AND MAY OPEN UP NEW THERAPEUTIC AVENUES. 2014 18 5071 27 PHYSICAL EXERCISE AND EPIGENETIC ADAPTATIONS OF THE CARDIOVASCULAR SYSTEM. DURING THE LAST DECADE, EPIGENETICS BECAME ONE OF THE FASTEST GROWING RESEARCH FIELDS IN NUMEROUS CLINICAL AND BASIC SCIENCE DISCIPLINES. EVIDENCE SUGGESTS THAT CHROMATIN MODIFICATIONS (E.G., HISTONE MODIFICATIONS AND DNA METHYLATION) AS WELL AS THE EXPRESSION OF MICRO-RNA MOLECULES PLAY A CRUCIAL ROLE IN THE PATHOGENESIS OF SEVERAL CARDIOVASCULAR DISEASES. ON THE ONE HAND, THEY ARE INVOLVED IN THE DEVELOPMENT OF GENERAL RISK FACTORS LIKE CHRONIC INFLAMMATION, BUT ON THE OTHER HAND, EPIGENETIC MODIFICATIONS ARE CONDUCIVE TO SMOOTH MUSCLE CELL, CARDIOMYOCYTE, AND ENDOTHELIAL PROGENITOR CELL PROLIFERATION/DIFFERENTIATION AS WELL AS TO EXTRACELLULAR MATRIX PROCESSING AND ENDOTHELIAL FUNCTION (E.G., ENDOTHELIAL NITRIC OXIDE SYNTHASE REGULATION). THEREFORE, EPIGENETIC MEDICAL DRUGS HAVE GAINED INCREASED ATTENTION AND PROVIDED THE FIRST PROMISING RESULTS IN THE CONTEXT OF CARDIOVASCULAR MALIGNANCIES. BESIDE OTHER LIFESTYLE FACTORS, PHYSICAL ACTIVITY AND SPORTS ESSENTIALLY CONTRIBUTE TO CARDIOVASCULAR HEALTH AND REGENERATION. IN THIS REVIEW WE FOCUS ON RECENT RESEARCH PROPOSING PHYSICAL ACTIVITY AS A POTENT EPIGENETIC REGULATOR THAT HAS THE POTENTIAL TO COUNTERACT PATHOPHYSIOLOGICAL ALTERATIONS IN ALMOST ALL THE AFOREMENTIONED CARDIOVASCULAR CELLS AND TISSUES. AS WITH EPIGENETIC MEDICAL DRUGS, MORE KNOWLEDGE ABOUT THE MOLECULAR MECHANISMS AND DOSE-RESPONSE RELATIONSHIPS OF EXERCISE IS NEEDED TO OPTIMIZE THE OUTCOME OF PREVENTIVE AND REHABILITATIVE EXERCISE PROGRAMS AND RECOMMENDATIONS. 2015 19 6626 30 UNDERSTANDING RESILIENCE. RESILIENCE IS THE ABILITY TO ADAPT SUCCESSFULLY IN THE FACE OF STRESS AND ADVERSITY. STRESSFUL LIFE EVENTS, TRAUMA, AND CHRONIC ADVERSITY CAN HAVE A SUBSTANTIAL IMPACT ON BRAIN FUNCTION AND STRUCTURE, AND CAN RESULT IN THE DEVELOPMENT OF POSTTRAUMATIC STRESS DISORDER (PTSD), DEPRESSION AND OTHER PSYCHIATRIC DISORDERS. HOWEVER, MOST INDIVIDUALS DO NOT DEVELOP SUCH ILLNESSES AFTER EXPERIENCING STRESSFUL LIFE EVENTS, AND ARE THUS THOUGHT TO BE RESILIENT. RESILIENCE AS SUCCESSFUL ADAPTATION RELIES ON EFFECTIVE RESPONSES TO ENVIRONMENTAL CHALLENGES AND ULTIMATE RESISTANCE TO THE DELETERIOUS EFFECTS OF STRESS, THEREFORE A GREATER UNDERSTANDING OF THE FACTORS THAT PROMOTE SUCH EFFECTS IS OF GREAT RELEVANCE. THIS REVIEW FOCUSES ON RECENT FINDINGS REGARDING GENETIC, EPIGENETIC, DEVELOPMENTAL, PSYCHOSOCIAL, AND NEUROCHEMICAL FACTORS THAT ARE CONSIDERED ESSENTIAL CONTRIBUTORS TO THE DEVELOPMENT OF RESILIENCE. NEURAL CIRCUITS AND PATHWAYS INVOLVED IN MEDIATING RESILIENCE ARE ALSO DISCUSSED. THE GROWING UNDERSTANDING OF RESILIENCE FACTORS WILL HOPEFULLY LEAD TO THE DEVELOPMENT OF NEW PHARMACOLOGICAL AND PSYCHOLOGICAL INTERVENTIONS FOR ENHANCING RESILIENCE AND MITIGATING THE UNTOWARD CONSEQUENCES. 2013 20 2617 36 EPIGENOME TARGETING BY PROBIOTIC METABOLITES. BACKGROUND: THE INTESTINAL MICROBIOTA PLAYS AN IMPORTANT ROLE IN IMMUNE DEVELOPMENT AND HOMEOSTASIS. A DISTURBED MICROBIOTA DURING EARLY INFANCY IS ASSOCIATED WITH AN INCREASED RISK OF DEVELOPING INFLAMMATORY AND ALLERGIC DISEASES LATER IN LIFE. THE MECHANISMS UNDERLYING THESE EFFECTS ARE POORLY UNDERSTOOD BUT ARE LIKELY TO INVOLVE ALTERATIONS IN MICROBIAL PRODUCTION OF FERMENTATION-DERIVED METABOLITES, WHICH HAVE POTENT IMMUNE MODULATING PROPERTIES AND ARE REQUIRED FOR MAINTENANCE OF HEALTHY MUCOSAL IMMUNE RESPONSES. PROBIOTICS ARE BENEFICIAL BACTERIA THAT HAVE THE CAPACITY TO ALTER THE COMPOSITION OF BACTERIAL SPECIES IN THE INTESTINE THAT CAN IN TURN INFLUENCE THE PRODUCTION OF FERMENTATION-DERIVED METABOLITES. PRINCIPAL AMONG THESE METABOLITES ARE THE SHORT-CHAIN FATTY ACIDS BUTYRATE AND ACETATE THAT HAVE POTENT ANTI-INFLAMMATORY ACTIVITIES IMPORTANT IN REGULATING IMMUNE FUNCTION AT THE INTESTINAL MUCOSAL SURFACE. THEREFORE STRATEGIES AIMED AT RESTORING THE MICROBIOTA PROFILE MAY BE EFFECTIVE IN THE PREVENTION OR TREATMENT OF ALLERGIC AND INFLAMMATORY DISEASES. PRESENTATION OF THE HYPOTHESIS: PROBIOTIC BACTERIA HAVE DIVERSE EFFECTS INCLUDING ALTERING MICROBIOTA COMPOSITION, REGULATING EPITHELIAL CELL BARRIER FUNCTION AND MODULATING OF IMMUNE RESPONSES. THE PRECISE MOLECULAR MECHANISMS MEDIATING THESE PROBIOTIC EFFECTS ARE NOT WELL UNDERSTOOD. SHORT-CHAIN FATTY ACIDS SUCH AS BUTYRATE ARE A CLASS OF HISTONE DEACETYLASE INHIBITORS IMPORTANT IN THE EPIGENETIC CONTROL OF HOST CELL RESPONSES. IT IS HYPOTHESIZED THAT THE BIOLOGICAL FUNCTION OF PROBIOTICS MAY BE A RESULT OF EPIGENETIC MODIFICATIONS THAT MAY EXPLAIN THE WIDE RANGE OF EFFECTS OBSERVED. STUDIES DELINEATING THE EFFECTS OF PROBIOTICS ON SHORT-CHAIN FATTY ACID PRODUCTION AND THE EPIGENETIC ACTIONS OF SHORT-CHAIN FATTY ACIDS WILL ASSIST IN UNDERSTANDING THE ASSOCIATION BETWEEN MICROBIOTA AND ALLERGIC OR AUTOIMMUNE DISORDERS. TESTING THE HYPOTHESIS: WE PROPOSE THAT TREATMENT WITH SPECIFIC PROBIOTIC BACTERIA UNDER IN VIVO CONDITIONS WOULD OFFER THE IDEAL CONDITIONS TO EXAMINE THE MICROBIOLOGICAL, IMMUNOLOGICAL AND EPIGENETIC MECHANISMS OF ACTION. ADVANCES IN EPIGENETIC TECHNOLOGY NOW ALLOW INVESTIGATORS TO BETTER UNDERSTAND THE COMPLEX BIOLOGICAL PROPERTIES OF PROBIOTICS AND THEIR METABOLITES. IMPLICATIONS OF THE HYPOTHESIS: DETERMINING THE PRECISE MECHANISMS OF PROBIOTIC ACTION WILL LEAD TO MORE SPECIFIC AND EFFICACIOUS THERAPEUTIC STRATEGIES IN THE PREVENTION OR TREATMENT OF CHRONIC INFLAMMATORY CONDITIONS. 2010