1 2836 149 FOOD INTAKE IN EARLY LIFE AND EPIGENETIC MODIFICATIONS OF PRO-OPIOMELANOCORTIN EXPRESSION IN ARCUATE NUCLEUS. THE PREVALENCE OF OBESITY IS INCREASING IN NOWADAYS SOCIETIES AND, DESPITE BEING A MULTIFACTORIAL DISEASE, IT HAS A SIGNIFICANT CORRELATION WITH FOOD INTAKE. THE CONTROL OF FOOD INTAKE IS PERFORMED BY NEURONS OF THE ARCUATE NUCLEUS OF THE HYPOTHALAMUS (ARC), WHICH SECRET OREXIGENIC AND ANOREXIGENIC NEUROPEPTIDES, SUCH AS PROOPIOMELANOCORTIN (POMC), UNDER STIMULATION OF, E.G., GHRELIN, INSULIN, AND LEPTIN. INSULIN, USES INOSITOL 1,4,5-TRISPHOSPHATE/SERINE-THREONINE KINASE (IP3/AKT) PATHWAYS AND STIMULATES THE EXCLUSION OF (FORKHEAD BOX PROTEIN O1) FOXO1 FROM THE NUCLEUS AND THEREBY DOES THE INACTIVATION OF THE INHIBITION OF POMC EXPRESSION, WHILE LEPTIN STIMULATES SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION 3 (STAT3) PHOSPHORYLATION AND POMC EXPRESSION. EPIGENETIC MODIFICATIONS OF THE SYNTHESIS OF THESE NEUROPEPTIDES CAN LEAD TO AN INCREASED CALORIC INTAKE, WHICH, IN TURN, IS AN IMPORTANT RISK FACTOR FOR OBESITY AND ITS COMORBIDITIES. EPIGENETIC MODIFICATIONS ARE REVERSIBLE, SO THE SEARCH FOR EPIGENETIC TARGETS HAS SIGNIFICANT SCIENTIFIC AND THERAPEUTIC APPEAL. IN THIS REVIEW, WE SYNTHESIZE THE EFFECT OF FOOD INTAKE ON THE EPIGENETIC MODIFICATIONS OF NEUROPEPTIDE Y AND PRO-OPIOMELANOCORTIN OF ARC AND ITS RELATIONSHIPS WITH OBESITY DEVELOPMENT AND COMORBIDITIES. WE FOUND THAT THERE IS NO CONSENSUS ON THE METHYLATION OF NEUROPEPTIDES WHEN THE EVALUATIONS ARE CARRIED OUT IN DIFFERENT PROMOTERS. BASED ON REPORTS CARRIED ON IN THE EARLY LIFE IN LABORATORY ANIMALS, WHICH IS THE TIMELINE THAT THE VAST MAJORITY OF AUTHOR USED TO STUDY THIS TOPIC, CHRONIC INFLAMMATION, DEFECTS IN INSULIN AND LEPTIN SIGNALING MAY BE LINKED TO CHANGES OCCURRING IN THE PHOSPHOINOSITIDE 3-KINASE/AKT (PI3K/AKT) AND/OR STAT3/SOCS3 (CYTOKINE SIGNALING 3) PATHWAYS. IN ITS TURN, THE EPIGENETIC MODIFICATIONS RELATED TO INCREASED FOOD INTAKE AND REDUCED ENERGY EXPENDITURE MAY BE ASSOCIATED WITH PI3K/AKT AND STAT3/SOCS3 SIGNALING DISRUPTION AND PRO-OPIOMELANOCORTIN EXPRESSION. 2021 2 2499 25 EPIGENETICS AND EXERCISE. EPIGENETICS CAN BE DEFINED AS 'THE STRUCTURAL ADAPTATION OF CHROMOSOMAL REGIONS SO AS TO REGISTER, SIGNAL, OR PERPETUATE ALTERED ACTIVITY STATES.' INCREASED TRANSCRIPTION OF KEY REGULATORY, METABOLIC, AND MYOGENIC GENES IS AN EARLY RESPONSE TO EXERCISE AND IS IMPORTANT IN MEDIATING SUBSEQUENT ADAPTATIONS IN SKELETAL MUSCLE. DNA HYPOMETHYLATION AND HISTONE HYPERACETYLATION ARE EMERGING AS IMPORTANT CRUCIAL EVENTS FOR INCREASED TRANSCRIPTION. THE COMPLEX INTERACTIONS BETWEEN MULTIPLE EPIGENETIC MODIFICATIONS AND THEIR REGULATION BY METABOLIC CHANGES AND SIGNALING EVENTS DURING EXERCISE, WITH IMPLICATIONS FOR ENHANCED UNDERSTANDING OF THE ACUTE AND CHRONIC ADAPTATIONS TO EXERCISE, ARE QUESTIONS FOR FURTHER INVESTIGATION. 2019 3 3123 38 GETTING AN INSIGHT INTO THE COMPLEXITY OF MAJOR CHRONIC INFLAMMATORY AND DEGENERATIVE DISEASES: A POTENTIAL NEW SYSTEMIC APPROACH TO THEIR TREATMENT. AS THE MODERN SOCIETY IS TROUBLED BY MULTI-FACTORIAL DISEASES, RESEARCH HAS BEEN CONDUCTED ON COMPLEX REALITIES INCLUDING CHRONIC INFLAMMATION, CANCER, OBESITY, HIV INFECTION, METABOLIC SYNDROME AND ITS DETRIMENTAL CARDIOVASCULAR COMPLICATIONS AS WELL AS DEPRESSION AND OTHER BRAIN DISORDERS. DETERIORATION OF CRUCIAL HOMEOSTATIC MECHANISMS IN SUCH DISEASES INVARIABLY RESULTS IN ACTIVATION OF INFLAMMATORY MEDIATORS, CHRONIC INFLAMMATION, LOSS IN IMMUNOLOGICAL FUNCTION, INCREASED SUSCEPTIBILITY TO DISEASES, ALTERATION OF METABOLISM, DECREASE OF ENERGY PRODUCTION AND NEURO-COGNITIVE DECLINE. REGULATION OF GENES EXPRESSION BY EPIGENETIC CODE IS THE DOMINANT MECHANISM FOR THE TRANSDUCTION OF ENVIRONMENTAL INPUTS, SUCH AS STRESS AND INFLAMMATION TO LASTING PHYSIOLOGICAL CHANGES. ACUTE AND CHRONIC STRESS DETERMINES DNA METHYLATION AND HISTONE MODIFICATIONS IN BRAIN REGIONS WHICH MAY CONTRIBUTE TO NEURO-DEGENERATIVE DISORDERS. NUCLEAR GLUCOCORTICOIDS RECEPTOR INTERACTS WITH THE EPIGENOMA RESULTING IN A CORTISOL RESISTANCE STATUS ASSOCIATED WITH A DETERIORATION OF THE METABOLIC AND IMMUNE FUNCTIONS. GONADAL STEROIDS RECEPTORS HAVE A SIMILAR CAPACITY TO PRODUCE EPIGENOMIC REORGANIZATION OF CHROMATINE STRUCTURE. EPIGENOMIC-INDUCED REDUCTION IN IMMUNE CELLS TELOMERES LENGTH HAS BEEN OBSERVED IN MANY DEGENERATIVE DISEASES, INCLUDING ALL TYPES OF CANCER. THE FINAL RESULT OF THESE EPIGENETIC ALTERATIONS IS A SERIOUS DAMAGE TO THE NEURO-ENDOCRINE-IMMUNE-METABOLIC ADAPTIVE SYSTEMS. IN THIS STUDY, WE PROPOSE A TREATMENT WITH STEM CELLS DIFFERENTIATION STAGE FACTORS TAKEN FROM ZEBRAFISH EMBRYOS WHICH ARE ABLE TO REGULATE THE GENES EXPRESSION OF NORMAL AND PATHOLOGICAL STEM CELLS IN A DIFFERENT SPECIFIC WAY. 2015 4 1796 36 EFFECT OF GERM-FREE STATUS ON TRANSCRIPTIONAL PROFILES IN THE NUCLEUS ACCUMBENS AND TRANSCRIPTOMIC RESPONSE TO CHRONIC MORPHINE. OPIOID USE DISORDER IS A PUBLIC HEALTH CRISIS THAT CAUSES TREMENDOUS SUFFERING FOR PATIENTS AS WELL AS SUBSTANTIAL SOCIAL AND ECONOMIC COSTS FOR SOCIETY. THERE ARE CURRENTLY AVAILABLE TREATMENTS FOR PATIENTS WITH OPIOID USE DISORDER, BUT THEY REMAIN INTOLERABLE OR INEFFECTIVE FOR MANY. THUS THE NEED TO DEVELOP NEW AVENUES FOR THERAPEUTICS DEVELOPMENT IN THIS SPACE IS GREAT. SUBSTANTIAL WORK IN MODELS OF SUBSTANCE USE DISORDERS, INCLUDING OPIOID USE DISORDER, DEMONSTRATES THAT PROLONGED EXPOSURE TO DRUGS OF ABUSE LEADS TO MARKED TRANSCRIPTIONAL AND EPIGENETIC DYSREGULATION IN LIMBIC SUBSTRUCTURES. IT IS WIDELY BELIEVED THAT THESE CHANGES IN GENE REGULATION IN RESPONSE TO DRUGS ARE A KEY DRIVING FACTOR IN THE PERPETUATION OF DRUG TAKING AND SEEKING BEHAVIORS. THUS, DEVELOPMENT OF INTERVENTIONS THAT COULD SHAPE TRANSCRIPTIONAL REGULATION IN RESPONSE TO DRUGS OF ABUSE WOULD BE OF HIGH VALUE. OVER THE PAST DECADE THERE HAS BEEN A SURGE IN RESEARCH DEMONSTRATING THAT THE RESIDENT BACTERIA OF THE GASTROINTESTINAL TRACT, COLLECTIVELY THE GUT MICROBIOME, CAN HAVE TREMENDOUS INFLUENCE ON NEUROBIOLOGICAL AND BEHAVIORAL PLASTICITY. PREVIOUS WORK FROM OUR GROUP AND OTHERS HAS DEMONSTRATED THAT ALTERATIONS IN THE GUT MICROBIOME CAN ALTER BEHAVIORAL RESPONSES TO OPIOIDS IN MULTIPLE PARADIGMS. ADDITIONALLY, WE HAVE PREVIOUSLY REPORTED THAT DEPLETION OF THE GUT MICROBIOME WITH ANTIBIOTICS MARKEDLY SHIFTS THE TRANSCRIPTOME OF THE NUCLEUS ACCUMBENS FOLLOWING PROLONGED MORPHINE EXPOSURE. IN THIS MANUSCRIPT WE PRESENT A COMPREHENSIVE ANALYSIS OF THE EFFECTS OF THE GUT MICROBIOME ON TRANSCRIPTIONAL REGULATION OF THE NUCLEUS ACCUMBENS FOLLOWING MORPHINE BY UTILIZING GERM-FREE, ANTIBIOTIC TREATED, AND CONTROL MICE. THIS ALLOWS FOR DETAILED UNDERSTANDING OF THE ROLE OF THE MICROBIOME IN REGULATING BASELINE TRANSCRIPTOMIC CONTROL, AS WELL AS RESPONSE TO MORPHINE. WE FIND THAT GERM-FREE STATUS LEADS TO A MARKED GENE DYSREGULATION IN A MANNER DISTINCT TO ADULT MICE TREATED WITH ANTIBIOTICS, AND THAT ALTERED GENE PATHWAYS ARE HIGHLY RELATED TO CELLULAR METABOLIC PROCESSES. THESE DATA PROVIDE ADDITIONAL INSIGHT INTO THE ROLE OF THE GUT MICROBIOME IN MODULATING BRAIN FUNCTION AND LAY A FOUNDATION FOR FURTHER STUDY IN THIS AREA. 2023 5 948 31 CHRONIC METABOLIC DERANGEMENT-INDUCED COGNITIVE DEFICITS AND NEUROTOXICITY ARE ASSOCIATED WITH REST INACTIVATION. CHRONIC METABOLIC ALTERATIONS MAY REPRESENT A RISK FACTOR FOR THE DEVELOPMENT OF COGNITIVE IMPAIRMENT, DEMENTIA, OR NEURODEGENERATIVE DISEASES. HYPERGLYCEMIA AND OBESITY ARE KNOWN TO IMPRINT EPIGENETIC MARKERS THAT COMPROMISE THE PROPER EXPRESSION OF CELL SURVIVAL GENES. HERE, WE SHOWED THAT CHRONIC HYPERGLYCEMIA (60 DAYS) INDUCED BY A SINGLE INTRAPERITONEAL INJECTION OF STREPTOZOTOCIN COMPROMISED COGNITION BY REDUCING HIPPOCAMPAL ERK SIGNALING AND BY INDUCING NEUROTOXICITY IN RATS. THE MECHANISMS APPEAR TO BE LINKED TO REDUCED ACTIVE DNA DEMETHYLATION AND DIMINISHED EXPRESSION OF THE NEUROPROTECTIVE TRANSCRIPTION FACTOR REST. THE IMPACT OF THE RELATIONSHIP BETWEEN ADIPOSITY AND DNA HYPERMETHYLATION ON REST EXPRESSION WAS ALSO DEMONSTRATED IN PERIPHERAL BLOOD MONONUCLEAR CELLS IN OBESE CHILDREN WITH REDUCED LEVELS OF BLOOD ASCORBATE. THE REVERSIBLE NATURE OF EPIGENETIC MODIFICATIONS AND THE COGNITIVE IMPAIRMENT REPORTED IN OBESE CHILDREN, ADOLESCENTS, AND ADULTS SUGGEST THAT THE CORRECTION OF THE ANTHROPOMETRY AND THE PERIPHERAL METABOLIC ALTERATIONS WOULD PROTECT BRAIN HOMEOSTASIS AND REDUCE THE RISK OF DEVELOPING NEURODEGENERATIVE DISEASES. 2019 6 5318 31 PSYCHONEUROENDOCRINE INTERVENTIONS AIMED AT ATTENUATING IMMUNOSENESCENCE: A REVIEW. THERE IS EVIDENCE SUGGESTING THAT IMMUNOSENESCENCE CAN BE ACCELERATED BY EXTERNAL FACTORS SUCH AS CHRONIC STRESS. HERE WE REVIEW POTENTIAL PSYCHONEUROENDOCRINE DETERMINANTS OF PREMATURE AGING OF THE IMMUNE SYSTEM AND DISCUSS AVAILABLE INTERVENTIONS AIMED AT ATTENUATING IMMUNOSENESCENCE. CHRONIC STRESS MAY ACCELERATE VARIOUS FEATURES OF IMMUNOSENESCENCE BY ACTIVATING KEY ALLOSTATIC SYSTEMS, NOTABLY THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS. THE IMMUNOLOGICAL IMPACT OF SUCH NEUROENDOCRINE DYSREGULATION MAY BE FURTHER AMPLIFIED BY A DRAMATIC DECLINE IN DEHYDROEPIANDROSTERONE (DHEA) LEVELS, ACTING IN PART AS AN ENDOGENOUS GLUCOCORTICOID ANTAGONIST. STRESS-BUFFERING STRATEGIES SHOW BENEFICIAL EFFECTS ON VARIOUS BIOMARKERS IN ELDERLY POPULATIONS. LIKEWISE, SUPPLEMENTATION OF DHEA, MELATONIN OR GROWTH HORMONE HAS YIELDED SIGNIFICANT BENEFICIAL EFFECTS IN A NUMBER OF STUDIES, INCLUDING: INCREASED WELL-BEING, MEMORY PERFORMANCE, BONE MINERAL DENSITY AND IMPROVED IMMUNOCOMPETENCE AS EVIDENCED BY RESULTS OF IN VITRO (T CELL PROLIFERATION, CYTOTOXICITY, CYTOKINE PRODUCTION), AND IN VIVO IMMUNE CHALLENGES. HOWEVER, THE SIDE-EFFECTS OF HORMONAL SUPPLEMENTATION ARE ALSO DISCUSSED. FINALLY, MODERATE EXERCISE VIA THE PROMOTION OF CORTISOL/DHEA BALANCE OR EPIGENETIC MODIFICATIONS, IS ASSOCIATED WITH LOWER SERUM PRO-INFLAMMATORY CYTOKINES, GREATER LYMPHOPROLIFERATIVE RESPONSES AND LOWER COUNTS OF SENESCENT T CELLS. TAKEN TOGETHER, THESE DATA SUGGEST THAT IMMUNE SYSTEM IS PLASTIC AND IMMUNOSENESCENCE CAN BE ATTENUATED PSYCHONEUROENDOCRINE INTERVENTIONS. 2013 7 1900 32 ENERGY SENSING PATHWAYS: BRIDGING TYPE 2 DIABETES AND COLORECTAL CANCER? THE RECENTLY RAPID INCREASE OF OBESITY AND TYPE 2 DIABETES MELLITUS HAS CAUSED GREAT BURDEN TO OUR SOCIETY. A POSITIVE ASSOCIATION BETWEEN TYPE 2 DIABETES AND RISK OF COLORECTAL CANCER HAS BEEN REPORTED BY INCREASING EPIDEMIOLOGICAL STUDIES. THE MOLECULAR MECHANISM OF THIS CONNECTION REMAINS ELUSIVE. HOWEVER, TYPE 2 DIABETES MAY RESULT IN ABNORMAL CARBOHYDRATE AND LIPID METABOLISM, HIGH LEVELS OF CIRCULATING INSULIN, INSULIN GROWTH FACTOR-1, AND ADIPOCYTOKINES, AS WELL AS CHRONIC INFLAMMATION. ALL THESE FACTORS COULD LEAD TO THE ALTERATION OF ENERGY SENSING PATHWAYS SUCH AS THE AMP ACTIVATED KINASE (PRKA), MECHANISTIC (MAMMALIAN) TARGET OF RAPAMYCIN (MTOR), SIRT1, AND AUTOPHAGY SIGNALING PATHWAYS. THE RESULTED IMPAIRED SIRT1 AND AUTOPHAGY SIGNALING PATHWAY COULD INCREASE THE RISK OF GENE MUTATION AND CANCER GENESIS BY DECREASING GENETIC STABILITY AND DNA MISMATCH REPAIR. THE DYSREGULATED MTOR AND PRKA PATHWAY COULD REMODEL CELL METABOLISM DURING THE GROWTH AND METASTASIS OF CANCER IN ORDER FOR THE CANCER CELL TO SURVIVE THE UNFAVORABLE MICROENVIRONMENT SUCH AS HYPOXIA AND LOW BLOOD SUPPLY. MOREOVER, THESE PATHWAYS MAY BE COUPLING METABOLIC AND EPIGENETIC ALTERATIONS THAT ARE CENTRAL TO ONCOGENIC TRANSFORMATION. FURTHER RESEARCHES INCLUDING MOLECULAR PATHOLOGIC EPIDEMIOLOGIC STUDIES ARE WARRANTED TO BETTER ADDRESS THE PRECISE LINKS BETWEEN THESE TWO IMPORTANT DISEASES. 2017 8 6342 44 THE ROLE OF EPIGENETIC REGULATOR SIRT1 IN BALANCING THE HOMEOSTASIS AND PREVENTING THE FORMATION OF SPECIFIC "SOIL" OF METABOLIC DISORDERS AND RELATED CANCERS. SIRT1 WAS DISCOVERED IN 1979 BUT GROWING INTEREST IN THIS PROTEIN OCCURRED ONLY 20 YEARS LATER WHEN ITS OVEREXPRESSION WAS REPORTED TO PROLONG THE LIFESPAN OF YEAST. SINCE THEN, SEVERAL STUDIES HAVE SHOWN THE BENEFITS OF ITS INCREASED EXPRESSION IN PREVENTING OR DELAYING OF MANY DISEASES. SIRT1, AS A HISTONE DEACETYLASE, IS AN EPIGENETIC REGULATOR BUT IT HAS WIDE RANGE OF NON-HISTONE TARGETS WHICH ARE INVOLVED IN METABOLISM, ENERGY SENSING PATHWAYS, CIRCADIAN MACHINERY AND IN INFLAMMATORY REGULATION. DISTURBANCES IN THESE INTERCONNECTED PROCESSES CAUSE DIFFERENT DISEASES, HOWEVER IT SEEMS THEY HAVE COMMON ROOTS IN UNBALANCED INFLAMMATORY PROCESSES AND LOWER LEVEL OR INACTIVATION OF SIRT1. SIRT1 INACTIVATION WAS IMPLICATED IN CORONAVIRUS DISEASE (COVID-19) SEVERITY AS WELL AND ITS LOW LEVEL COUNTED AS A PREDICTOR OF UNCONTROLLED COVID-19. SEVERAL OTHER DISEASES SUCH AS METABOLIC DISEASE, OBESITY, DIABETES, ALZHEIMER'S DISEASE, CARDIOVASCULAR DISEASE OR DEPRESSION ARE RELATED TO CHRONIC INFLAMMATION AND SIMILARLY SHOW DECREASED SIRT1 LEVEL. IT HAS RECENTLY BEEN KNOWN THAT SIRT1 IS INDUCIBLE BY CALORIE RESTRICTION/PROPER DIET, PHYSICAL ACTIVITY AND APPROPRIATE EMOTIONAL STATE. INDEED, A HEALTHIER METABOLIC STATE BELONGS TO HIGHER LEVEL OF SIRT1 EXPRESSION. THESE SUGGEST THAT APPROPRIATE LIFESTYLE AS NON-PHARMACOLOGICAL TREATMENT MAY BE A BENEFICIAL TOOL IN THE PREVENTION OF INFLAMMATION OR METABOLIC DISTURBANCE-RELATED DISEASES AS WELL AS COULD BE A PART OF THE COMPLEMENTARY THERAPY IN MEDICAL PRACTICE TO REACH BETTER THERAPEUTIC RESPONSE AND QUALITY OF LIFE. WE AIMED IN THIS REVIEW TO LINK THE BENEFICIAL EFFECT OF SIRT1 WITH THOSE DISEASES, WHERE ITS LEVEL DECREASED. MOREOVER, WE AIMED TO COLLECT EVIDENCES OF INTERVENTIONS OR TREATMENTS, WHICH INCREASE SIRT1 EXPRESSION AND THUS, OPEN THE POSSIBILITY TO USE THEM AS PREVENTIVE OR COMPLEMENTARY THERAPIES IN MEDICAL PRACTICE. 2022 9 679 21 BRAIN FOODS - THE ROLE OF DIET IN BRAIN PERFORMANCE AND HEALTH. THE PERFORMANCE OF THE HUMAN BRAIN IS BASED ON AN INTERPLAY BETWEEN THE INHERITED GENOTYPE AND EXTERNAL ENVIRONMENTAL FACTORS, INCLUDING DIET. FOOD AND NUTRITION, ESSENTIAL IN MAINTENANCE OF BRAIN PERFORMANCE, ALSO AID IN PREVENTION AND TREATMENT OF MENTAL DISORDERS. BOTH THE OVERALL COMPOSITION OF THE HUMAN DIET AND SPECIFIC DIETARY COMPONENTS HAVE BEEN SHOWN TO HAVE AN IMPACT ON BRAIN FUNCTION IN VARIOUS EXPERIMENTAL MODELS AND EPIDEMIOLOGICAL STUDIES. THIS NARRATIVE REVIEW PROVIDES AN OVERVIEW OF THE ROLE OF DIET IN 5 KEY AREAS OF BRAIN FUNCTION RELATED TO MENTAL HEALTH AND PERFORMANCE, INCLUDING: (1) BRAIN DEVELOPMENT, (2) SIGNALING NETWORKS AND NEUROTRANSMITTERS IN THE BRAIN, (3) COGNITION AND MEMORY, (4) THE BALANCE BETWEEN PROTEIN FORMATION AND DEGRADATION, AND (5) DETERIORATIVE EFFECTS DUE TO CHRONIC INFLAMMATORY PROCESSES. FINALLY, THE ROLE OF DIET IN EPIGENETIC REGULATION OF BRAIN PHYSIOLOGY IS DISCUSSED. 2021 10 2523 41 EPIGENETICS AND THE TRANSITION FROM ACUTE TO CHRONIC PAIN. OBJECTIVE: THE OBJECTIVE OF THIS STUDY WAS TO REVIEW THE EPIGENETIC MODIFICATIONS INVOLVED IN THE TRANSITION FROM ACUTE TO CHRONIC PAIN AND TO IDENTIFY POTENTIAL TARGETS FOR THE DEVELOPMENT OF NOVEL, INDIVIDUALIZED PAIN THERAPEUTICS. BACKGROUND: EPIGENETICS IS THE STUDY OF HERITABLE MODIFICATIONS IN GENE EXPRESSION AND PHENOTYPE THAT DO NOT REQUIRE A CHANGE IN GENETIC SEQUENCE TO MANIFEST THEIR EFFECTS. ENVIRONMENTAL TOXINS, MEDICATIONS, DIET, AND PSYCHOLOGICAL STRESSES CAN ALTER EPIGENETIC PROCESSES SUCH AS DNA METHYLATION, HISTONE ACETYLATION, AND RNA INTERFERENCE. AS EPIGENETIC MODIFICATIONS POTENTIALLY PLAY AN IMPORTANT ROLE IN INFLAMMATORY CYTOKINE METABOLISM, STEROID RESPONSIVENESS, AND OPIOID SENSITIVITY, THEY ARE LIKELY KEY FACTORS IN THE DEVELOPMENT OF CHRONIC PAIN. ALTHOUGH OUR KNOWLEDGE OF THE HUMAN GENETIC CODE AND DISEASE-ASSOCIATED POLYMORPHISMS HAS GROWN SIGNIFICANTLY IN THE PAST DECADE, WE HAVE NOT YET BEEN ABLE TO ELUCIDATE THE MECHANISMS THAT LEAD TO THE DEVELOPMENT OF PERSISTENT PAIN AFTER NERVE INJURY OR SURGERY. DESIGN: THIS IS A FOCUSED LITERATURE REVIEW OF EPIGENETIC SCIENCE AND ITS RELATIONSHIP TO CHRONIC PAIN. RESULTS: SIGNIFICANT LABORATORY AND CLINICAL DATA SUPPORT THE NOTION THAT EPIGENETIC MODIFICATIONS ARE AFFECTED BY THE ENVIRONMENT AND LEAD TO DIFFERENTIAL GENE EXPRESSION. SIMILAR TO MECHANISMS INVOLVED IN THE DEVELOPMENT OF CANCER, NEURODEGENERATIVE DISEASE, AND INFLAMMATORY DISORDERS, THE LITERATURE ENDORSES AN IMPORTANT POTENTIAL ROLE FOR EPIGENETICS IN CHRONIC PAIN. CONCLUSIONS: EPIGENETIC ANALYSIS MAY IDENTIFY MECHANISMS CRITICAL TO THE DEVELOPMENT OF CHRONIC PAIN AFTER INJURY, AND MAY PROVIDE NEW PATHWAYS AND TARGET MECHANISMS FOR FUTURE DRUG DEVELOPMENT AND INDIVIDUALIZED MEDICINE. 2012 11 6866 32 [PAIN AND EMOTIONAL DYSREGULATION: CELLULAR MEMORY DUE TO PAIN]. GENETIC FACTORS ARE INVOLVED IN DETERMINANTS FOR THE RISK OF PSYCHIATRIC DISORDERS, AND NEUROLOGICAL AND NEURODEGENERATIVE DISEASES. CHRONIC PAIN STIMULI AND INTENSE PAIN HAVE EFFECTS AT A CELLULAR AND/OR GENE EXPRESSION LEVEL, AND WILL EVENTUALLY INDUCE "CELLULAR MEMORY DUE TO PAIN", WHICH MEANS THAT TISSUE DAMAGE, EVEN IF ONLY TRANSIENT, CAN ELICIT EPIGENETICALLY ABNORMAL TRANSCRIPTION/TRANSLATION AND POST-TRANSLATIONAL MODIFICATION IN RELATED CELLS DEPENDING ON THE DEGREE OR KIND OF INJURY OR ASSOCIATED CONDITIONS. SUCH CELL MEMORY/TRANSFORMATION DUE TO PAIN CAN CAUSE AN ABNORMALITY IN A FUNDAMENTAL INTRACELLULAR RESPONSE, SUCH AS A CHANGE IN THE THREE-DIMENSIONAL STRUCTURE OF DNA, TRANSCRIPTION, OR TRANSLATION. ON THE OTHER HAND, PAIN IS A MULTIDIMENSIONAL EXPERIENCE WITH SENSORY-DISCRIMINATIVE AND MOTIVATIONAL-AFFECTIVE COMPONENTS. RECENT HUMAN BRAIN IMAGING STUDIES HAVE EXAMINED DIFFERENCES IN ACTIVITY IN THE NUCLEUS ACCUMBENS BETWEEN CONTROLS AND PATIENTS WITH CHRONIC PAIN, AND HAVE REVEALED THAT THE NUCLEUS ACCUMBENS PLAYS A ROLE IN PREDICTING THE VALUE OF A NOXIOUS STIMULUS AND ITS OFFSET, AND IN THE CONSEQUENT CHANGES IN THE MOTIVATIONAL STATE. IN THIS REVIEW, WE PROVIDE A VERY BRIEF OVERVIEW OF A COMPREHENSIVE UNDERSTANDING OF CHRONIC PAIN ASSOCIATED WITH EMOTIONAL DYSREGULATION DUE TO TRANSCRIPTIONAL REGULATION, EPIGENETIC MODIFICATION AND MIRNA REGULATION. 2015 12 6257 28 THE MOLECULAR BASIS OF TOLERANCE. TOLERANCE IS DEFINED AS THE DIMINISHED RESPONSE TO ALCOHOL OR OTHER DRUGS OVER THE COURSE OF REPEATED OR PROLONGED EXPOSURE. THIS MECHANISM ALLOWS PHYSIOLOGICAL PROCESSES TO ACHIEVE STABILITY IN A CONSTANTLY CHANGING ENVIRONMENT. THE ONSET OF TOLERANCE MAY OCCUR WITHIN MINUTES, DURING A SINGLE EXPOSURE TO ALCOHOL (I.E., ACUTE TOLERANCE), OR OVER LONGER TIMEFRAMES AND WITH PROLONGED EXPOSURE TO ALCOHOL (I.E., RAPID OR CHRONIC TOLERANCE). CHANGES IN TOLERANCE INDUCED BY ALCOHOL MAY AFFECT SEVERAL PROCESSES AT THE MOLECULAR, CELLULAR, OR BEHAVIORAL LEVEL. THESE EFFECTS OFTEN ARE INTERRELATED AND MAY BE DIFFICULT TO SEPARATE. THIS ARTICLE DESCRIBES CHANGES AT THE MOLECULAR LEVEL THAT ARE RELATED TO THE ONSET OF ACUTE, RAPID, OR CHRONIC TOLERANCE. IT FOCUSES ON NEURONAL MEMBRANE-BOUND CHANNELS AND THE FACTORS THAT AFFECT THEIR FUNCTION AND PRODUCTION, SUCH AS MODIFICATION OF PROTEIN SYNTHESIS AND ACTIVITY, INTERACTION WITH THE MEMBRANE LIPID MICROENVIRONMENT, EPIGENETIC EFFECTS ON CYTOPLASMIC REGULATION, AND GENE TRANSCRIPTION. ALSO CONSIDERED IS THE GENETICS OF TOLERANCE. 2008 13 5645 29 SEX DEPENDENT ALTERATION OF EPIGENETIC MARKS AFTER CHRONIC MORPHINE TREATMENT IN MICE ORGANS. EPIGENETIC MARKS MAY BE ALSO AFFECTED BY SEVERAL FACTORS, SUCH AS AGE, LIFESTYLE, EARLY LIFE EXPERIENCES AND EXPOSURE TO CHEMICALS OR DRUGS, SUCH AS OPIOIDS. PREVIOUS STUDIES HAVE FOCUSED ON HOW MORPHINE EPIGENETICALLY REGULATES DIFFERENT REGIONS OF THE BRAIN THAT ARE IMPLICATED IN TOLERANCE, DEPENDENCE AND OTHER PSYCHIATRIC DISORDERS MORE RELATED TO THE PHYSIO-PATHOLOGICAL EFFECTS OF OPIOIDS. NEVERTHELESS, A SIGNIFICANT KNOWLEDGE GAP REMAINS REGARDING THE EFFECT OF CHRONIC TREATMENT ON OTHER ORGANS AND BIOLOGICAL SYSTEMS. THEREFORE, THE AIM OF THIS WORK IS TO INCREASE OUR KNOWLEDGE ABOUT THE IMPACT OF CHRONIC MORPHINE EXPOSURE ON DNA METHYLATION AND HISTONE MODIFICATION LEVELS IN EACH OF THE ORGANS OF MALE AND FEMALE MODEL MICE IN VIVO. OUR RESULTS REVEAL, FOR THE FIRST TIME, THAT CHRONIC MORPHINE TREATMENT INDUCED CHANGES IN DNA METHYLATION/HYDROXYMETHYLATION AND HISTONE MODIFICATION IN-VIVO AT THE SYSTEMIC LEVEL, REVEALING A POTENTIAL PHYSIOLOGICAL EFFECT ON THE REGULATION OF GENE EXPRESSION. NOTABLY, MORPHINE-INDUCED EPIGENETIC MODIFICATION OCCURS IN A SEX-DEPENDENT MANNER, REVEALING THE EXISTENCE OF DIFFERENT UNDERLYING MECHANISMS OF EPIGENETIC MODIFICATION IN MALE AND FEMALE MICE. 2021 14 5756 30 SOCIOECONOMIC DEPRIVATION, ADVERSE CHILDHOOD EXPERIENCES AND MEDICAL DISORDERS IN ADULTHOOD: MECHANISMS AND ASSOCIATIONS. SEVERE SOCIOECONOMIC DEPRIVATION (SED) AND ADVERSE CHILDHOOD EXPERIENCES (ACE) ARE SIGNIFICANTLY ASSOCIATED WITH THE DEVELOPMENT IN ADULTHOOD OF (I) ENHANCED INFLAMMATORY STATUS AND/OR HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS DYSFUNCTION AND (II) NEUROLOGICAL, NEUROPROGRESSIVE, INFLAMMATORY AND AUTOIMMUNE DISEASES. THE MECHANISMS BY WHICH THESE ASSOCIATIONS TAKE PLACE ARE DETAILED. THE TWO SETS OF CONSEQUENCES ARE THEMSELVES STRONGLY ASSOCIATED, WITH THE FIRST SET LIKELY CONTRIBUTING TO THE SECOND. MECHANISMS ENABLING BIDIRECTIONAL COMMUNICATION BETWEEN THE IMMUNE SYSTEM AND THE BRAIN ARE DESCRIBED, INCLUDING COMPLEX SIGNALLING PATHWAYS FACILITATED BY FACTORS AT THE LEVEL OF IMMUNE CELLS. ALSO DETAILED ARE MECHANISMS UNDERPINNING THE ASSOCIATION BETWEEN SED, ACE AND THE GENESIS OF PERIPHERAL INFLAMMATION, INCLUDING EPIGENETIC CHANGES TO IMMUNE SYSTEM-RELATED GENE EXPRESSION. THE DURATION AND MAGNITUDE OF INFLAMMATORY RESPONSES CAN BE INFLUENCED BY GENETIC FACTORS, INCLUDING SINGLE NUCLEOTIDE POLYMORPHISMS, AND BY EPIGENETIC FACTORS, WHEREBY PRO-INFLAMMATORY CYTOKINES, REACTIVE OXYGEN SPECIES, REACTIVE NITROGEN SPECIES AND NUCLEAR FACTOR-KAPPAB AFFECT GENE DNA METHYLATION AND HISTONE ACETYLATION AND ALSO INDUCE SEVERAL MICRORNAS INCLUDING MIR-155, MIR-181B-1 AND MIR-146A. ADULT HPA AXIS ACTIVITY IS REGULATED BY (I) GENETIC FACTORS, SUCH AS GLUCOCORTICOID RECEPTOR POLYMORPHISMS; (II) EPIGENETIC FACTORS AFFECTING GLUCOCORTICOID RECEPTOR FUNCTION OR EXPRESSION, INCLUDING THE METHYLATION STATUS OF ALTERNATIVE PROMOTER REGIONS OF NR3C1 AND THE METHYLATION OF FKBP5 AND HSD11BETA2; (III) CHRONIC INFLAMMATION AND CHRONIC NITROSATIVE AND OXIDATIVE STRESS. FINALLY, IT IS SHOWN HOW SEVERE PSYCHOLOGICAL STRESS ADVERSELY AFFECTS MITOCHONDRIAL STRUCTURE AND FUNCTIONING AND IS ASSOCIATED WITH CHANGES IN BRAIN MITOCHONDRIAL DNA COPY NUMBER AND TRANSCRIPTION; MITOCHONDRIA CAN ACT AS COURIERS OF CHILDHOOD STRESS INTO ADULTHOOD. 2019 15 4093 29 MATERNAL SEPARATION FOLLOWED BY CHRONIC MILD STRESS IN ADULTHOOD IS ASSOCIATED WITH CONCERTED EPIGENETIC REGULATION OF AP-1 COMPLEX GENES. DEPRESSION IS ONE OF THE MOST PREVALENT MENTAL DISEASES WORLDWIDE. PATIENTS WITH PSYCHIATRIC DISEASES OFTEN HAVE A HISTORY OF CHILDHOOD NEGLECT, INDICATING THAT EARLY-LIFE EXPERIENCES PREDISPOSE TO PSYCHIATRIC DISEASES IN ADULTHOOD. TWO STRONG MODELS WERE USED IN THE PRESENT STUDY: THE MATERNAL SEPARATION/EARLY DEPRIVATION MODEL (MS) AND THE CHRONIC MILD STRESS MODEL (CMS). IN BOTH MODELS, WE FOUND CHANGES IN THE EXPRESSION OF A NUMBER OF GENES SUCH AS CREB AND NPY. STRIKINGLY, THERE WAS A CLEAR REGULATION OF EXPRESSION OF FOUR GENES INVOLVED IN THE AP-1 COMPLEX: C-FOS, C-JUN, FOSB, AND JUN-B. INTERESTINGLY, DIFFERENT EXPRESSION LEVELS WERE OBSERVED DEPENDING ON THE MODEL, WHEREAS THE COMBINATION OF THE MODELS RESULTED IN A NORMAL LEVEL OF GENE EXPRESSION. THE EFFECTS OF MS AND CMS ON GENE EXPRESSION WERE ASSOCIATED WITH DISTINCT HISTONE METHYLATION/ACETYLATION PATTERNS OF ALL FOUR GENES. THE EPIGENETIC CHANGES, LIKE GENE EXPRESSION, WERE ALSO DEPENDENT ON THE SPECIFIC STRESSOR OR THEIR COMBINATION. THE OBTAINED RESULTS SUGGEST THAT SINGLE LIFE EVENTS LEAVE A MARK ON GENE EXPRESSION AND THE EPIGENETIC SIGNATURE OF GENE PROMOTERS, BUT A COMBINATION OF DIFFERENT STRESSORS AT DIFFERENT LIFE STAGES CAN FURTHER CHANGE GENE EXPRESSION THROUGH EPIGENETIC FACTORS, POSSIBLY CAUSING THE LONG-LASTING ADVERSE EFFECTS OF STRESS. 2021 16 6133 33 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 17 4648 36 NEUROPEPTIDE Y IN ALCOHOL ADDICTION AND AFFECTIVE DISORDERS. NEUROPEPTIDE Y (NPY), A NEUROPEPTIDE HIGHLY CONSERVED THROUGHOUT EVOLUTION, IS PRESENT AT HIGH LEVELS IN THE CENTRAL NERVOUS SYSTEM (CNS), AS WELL AS IN PERIPHERAL TISSUES SUCH AS THE GUT AND CARDIOVASCULAR SYSTEM. THE PEPTIDE EXERTS ITS EFFECTS VIA MULTIPLE RECEPTOR SUBTYPES, ALL BELONGING TO THE G-PROTEIN-COUPLED RECEPTOR SUPERFAMILY. OF THESE SUBTYPES, THE Y1 AND THE Y2 ARE THE MOST THOROUGHLY CHARACTERIZED, FOLLOWED BY THE Y5 SUBTYPE. NPY AND ITS RECEPTORS HAVE BEEN SHOWN TO BE OF IMPORTANCE IN CENTRAL REGULATION OF EVENTS UNDERLYING, FOR EXAMPLE, AFFECTIVE DISORDERS, DRUG/ALCOHOL USE DISORDERS, AND ENERGY HOMEOSTASIS. FURTHERMORE, WITHIN THE CNS, NPY ALSO AFFECTS SLEEP REGULATION AND CIRCADIAN RHYTHM, MEMORY FUNCTION, TISSUE GROWTH, AND PLASTICITY. THE POTENTIAL ROLES OF NPY IN THE ETIOLOGY AND PATHOPHYSIOLOGY OF MOOD AND ANXIETY DISORDERS, AS WELL AS ALCOHOL USE DISORDERS, HAVE BEEN EXTENSIVELY STUDIED. THIS FOCUS WAS PROMPTED BY EARLY INDICATIONS FOR AN INVOLVEMENT OF NPY IN ACUTE RESPONSES TO STRESS, AND, LATER, ALSO DATA POINTING TO A ROLE IN ALTERATIONS WITHIN THE CNS DURING CHRONIC, OR REPEATED, EXPOSURE TO ADVERSE EVENTS. THESE FUNCTIONS OF NPY, IN ADDITION TO THE PEPTIDE'S REGULATION OF DISEASE STATES, SUGGEST THAT MODULATION OF THE ACTIVITY OF THE NPY SYSTEM VIA RECEPTOR AGONISTS/ANTAGONISTS MAY BE A PUTATIVE TREATMENT MECHANISM IN AFFECTIVE DISORDERS AS WELL AS ALCOHOL USE DISORDERS. IN THIS REVIEW, WE PRESENT AN OVERVIEW OF FINDINGS WITH REGARD TO THE NPY SYSTEM IN RELATION TO ANXIETY AND STRESS, ACUTE AS WELL AS CHRONIC; FURTHERMORE WE DISCUSS POST-TRAUMATIC STRESS DISORDER AND, IN PART DEPRESSION. IN ADDITION, WE SUMMARIZE FINDINGS ON ALCOHOL USE DISORDERS AND RELATED BEHAVIORS. FINALLY, WE BRIEFLY TOUCH UPON GENETIC AS WELL AS EPIGENETIC MECHANISMS THAT MAY BE OF IMPORTANCE FOR NPY FUNCTION AND REGULATION. IN CONCLUSION, WE SUGGEST THAT MODULATION OF NPY-ERGIC ACTIVITY WITHIN THE CNS, VIA LIGANDS AIMED AT DIFFERENT RECEPTOR SUBTYPES, MAY BE ATTRACTIVE TARGETS FOR TREATMENT DEVELOPMENT FOR AFFECTIVE DISORDERS, AS WELL AS FOR ALCOHOL USE DISORDERS. 2017 18 2520 28 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 5711 35 SIRT1 IS A HIGHLY NETWORKED PROTEIN THAT MEDIATES THE ADAPTATION TO CHRONIC PHYSIOLOGICAL STRESS. SIRT1 IS A NAD(+)-DEPENDENT PROTEIN DEACETYLASE THAT HAS A VERY LARGE NUMBER OF ESTABLISHED PROTEIN SUBSTRATES AND AN EQUALLY IMPRESSIVE LIST OF BIOLOGICAL FUNCTIONS THOUGHT TO BE REGULATED BY ITS ACTIVITY. PERHAPS AS NOTABLE IS THE REMARKABLE NUMBER OF POINTS OF CONFLICT CONCERNING THE ROLE OF SIRT1 IN BIOLOGICAL PROCESSES. FOR EXAMPLE, EVIDENCE EXISTS SUGGESTING THAT SIRT1 IS A TUMOR SUPPRESSOR, IS AN ONCOGENE, OR HAS NO EFFECT ON ONCOGENESIS. SIMILARLY, SIRT1 IS VARIABLY REPORTED TO INDUCE, INHIBIT, OR HAVE NO EFFECT ON AUTOPHAGY. WE BELIEVE THAT THE RESOLUTION OF MANY CONFLICTING RESULTS IS POSSIBLE BY CONSIDERING RECENT REPORTS INDICATING THAT SIRT1 IS AN IMPORTANT HUB INTERACTING WITH A COMPLEX NETWORK OF PROTEINS THAT COLLECTIVELY REGULATE A WIDE VARIETY OF BIOLOGICAL PROCESSES INCLUDING CANCER AND AUTOPHAGY. A NUMBER OF THE INTERACTING PROTEINS ARE THEMSELVES HUBS THAT, LIKE SIRT1, UTILIZE INTRINSICALLY DISORDERED REGIONS FOR THEIR PROMISCUOUS INTERACTIONS. MANY STUDIES INVESTIGATING SIRT1 FUNCTION HAVE BEEN CARRIED OUT ON CELL LINES CARRYING UNDETERMINED NUMBERS OF ALTERATIONS TO THE PROTEINS COMPRISING THE SIRT1 NETWORK OR ON INBRED MOUSE STRAINS CARRYING FIXED MUTATIONS AFFECTING SOME OF THESE PROTEINS. THUS, THE EFFECTS OF MODULATING SIRT1 AMOUNT AND/OR ACTIVITY ARE IMPORTANTLY DETERMINED BY THE GENETIC BACKGROUND OF THE CELL (OR THE INBRED STRAIN OF MICE), AND THE EFFECTS ATTRIBUTED TO SIRT1 ARE SYNTHETIC WITH THE BACKGROUND OF MUTATIONS AND EPIGENETIC DIFFERENCES BETWEEN CELLS AND ORGANISMS. WORK ON MICE CARRYING ALTERATIONS TO THE SIRT1 GENE SUGGESTS THAT THE NETWORK IN WHICH SIRT1 FUNCTIONS PLAYS AN IMPORTANT ROLE IN MEDIATING PHYSIOLOGICAL ADAPTATION TO VARIOUS SOURCES OF CHRONIC STRESS SUCH AS CALORIE RESTRICTION AND CALORIE OVERLOAD. WHETHER THE CATALYTIC ACTIVITY OF SIRT1 AND THE NUCLEAR CONCENTRATION OF THE CO-FACTOR, NAD(+), ARE RESPONSIBLE FOR MODULATING THIS ACTIVITY REMAINS TO BE DETERMINED. HOWEVER, THE EFFECT OF MODULATING SIRT1 ACTIVITY MUST BE INTERPRETED IN THE CONTEXT OF THE CELL OR TISSUE UNDER INVESTIGATION. INDEED, FOR SIRT1, WE ARGUE THAT CONTEXT IS EVERYTHING. 2013 20 2346 39 EPIGENETIC REGULATION OF METABOLISM AND INFLAMMATION BY CALORIE RESTRICTION. CHRONIC CALORIC RESTRICTION (CR) WITHOUT MALNUTRITION IS KNOWN TO AFFECT DIFFERENT CELLULAR PROCESSES SUCH AS STEM CELL FUNCTION, CELL SENESCENCE, INFLAMMATION, AND METABOLISM. DESPITE THE DIFFERENCES IN THE IMPLEMENTATION OF CR, THE REDUCTION OF CALORIES PRODUCES A WIDESPREAD BENEFICIAL EFFECT IN NONCOMMUNICABLE CHRONIC DISEASES, WHICH CAN BE EXPLAINED BY IMPROVEMENTS IN IMMUNO-METABOLIC ADAPTATION. CELLULAR ADAPTATION THAT OCCURS IN RESPONSE TO DIETARY PATTERNS CAN BE EXPLAINED BY ALTERATIONS IN EPIGENETIC MECHANISMS SUCH AS DNA METHYLATION, HISTONE MODIFICATIONS, AND MICRORNA. IN THIS REVIEW, WE DEFINE THESE MODIFICATIONS AND SYSTEMATICALLY SUMMARIZE THE CURRENT EVIDENCE RELATED TO CR AND THE EPIGENOME. WE THEN EXPLAIN THE SIGNIFICANCE OF GENOME-WIDE EPIGENETIC MODIFICATIONS IN THE CONTEXT OF DISEASE DEVELOPMENT. ALTHOUGH SUBSTANTIAL EVIDENCE EXISTS FOR THE WIDESPREAD EFFECT OF CR ON LONGEVITY, THERE IS NO CONSENSUS REGARDING THE EPIGENETIC REGULATIONS OF THE UNDERLYING CELLULAR MECHANISMS THAT LEAD TO IMPROVED HEALTH. WE PROVIDE COMPELLING EVIDENCE THAT CR PRODUCES LONG-LASTING EPIGENETIC EFFECTS THAT MEDIATE EXPRESSION OF GENES RELATED TO IMMUNO-METABOLIC PROCESSES. EPIGENETIC REPROGRAMMING OF THE UNDERLYING CHRONIC LOW-GRADE INFLAMMATION BY CR CAN LEAD TO IMMUNO-METABOLIC ADAPTATIONS THAT ENHANCE QUALITY OF LIFE, EXTEND LIFESPAN, AND DELAY CHRONIC DISEASE ONSET. 2019