1 3148 149 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 2 997 38 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 3 4093 38 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 4 5067 35 PHYSICAL ACTIVITY AND DNA METHYLATION IN HUMANS. PHYSICAL ACTIVITY IS A STRONG STIMULUS INFLUENCING THE OVERALL PHYSIOLOGY OF THE HUMAN BODY. EXERCISES LEAD TO BIOCHEMICAL CHANGES IN VARIOUS TISSUES AND EXERT AN IMPACT ON GENE EXPRESSION. EXERCISE-INDUCED CHANGES IN GENE EXPRESSION MAY BE MEDIATED BY EPIGENETIC MODIFICATIONS, WHICH REARRANGE THE CHROMATIN STRUCTURE AND THEREFORE MODULATE ITS ACCESSIBILITY FOR TRANSCRIPTION FACTORS. ONE OF SUCH EPIGENETIC MARK IS DNA METHYLATION THAT INVOLVES AN ATTACHMENT OF A METHYL GROUP TO THE FIFTH CARBON OF CYTOSINE RESIDUE PRESENT IN CG DINUCLEOTIDES (CPG). DNA METHYLATION IS CATALYZED BY A FAMILY OF DNA METHYLTRANSFERASES. THIS REVERSIBLE DNA MODIFICATION RESULTS IN THE RECRUITMENT OF PROTEINS CONTAINING METHYL BINDING DOMAIN AND FURTHER TRANSCRIPTIONAL CO-REPRESSORS LEADING TO THE SILENCING OF GENE EXPRESSION. THE ACCUMULATION OF CPG DINUCLEOTIDES, REFERRED AS CPG ISLANDS, OCCURS AT THE PROMOTER REGIONS IN A GREAT MAJORITY OF HUMAN GENES. THEREFORE, CHANGES IN DNA METHYLATION PROFILE AFFECT THE TRANSCRIPTION OF MULTIPLE GENES. A GROWING BODY OF EVIDENCE INDICATES THAT EXERCISE TRAINING MODULATES DNA METHYLATION IN MUSCLES AND ADIPOSE TISSUE. SOME OF THESE EPIGENETIC MARKERS WERE ASSOCIATED WITH A REDUCED RISK OF CHRONIC DISEASES. THIS REVIEW SUMMARIZES THE CURRENT KNOWLEDGE ABOUT THE INFLUENCE OF PHYSICAL ACTIVITY ON THE DNA METHYLATION STATUS IN HUMANS. 2021 5 2499 30 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 6 6771 38 [ACQUIRED DISORDERS AND EPIGENETICS]. EPIGENETIC MODIFICATIONS, INVOLVING DNA METHYLATION AND HISTONE MODIFICATIONS, ARE MAINTAINED UPON SOMATIC CELL REPLICATION, AND ARE FUNDAMENTAL MECHANISMS FOR CELLULAR MEMORY. DNA METHYLATION OF PROMOTER CPG ISLANDS OF TUMOR-SUPPRESSOR GENES CAN SILENCE THEIR DOWNSTREAM GENES, AND CAN BE CAUSALLY INVOLVED IN CANCER DEVELOPMENT AND PROGRESSION. SINCE THIS EFFECT IS THE SAME WITH THAT OF INACTIVATING MUTATIONS, THE NATURES OF DNA METHYLATION WERE ONCE CONSIDERED TO BE SIMILAR TO MUTATIONS. HOWEVER, RECENTLY, IT WAS REVEALED THAT A LARGE NUMBER OF EPIGENETIC ALTERATIONS ARE PRESENT IN A SINGLE CANCER CELL, THAT A LARGE NUMBER OF CELLS HAVE AN EPIGENETIC ALTERATION OF A SPECIFIC GENE IN NON-CANCEROUS, THUS POLYCLONAL, TISSUES, THAT GENE SPECIFICITY IN METHYLATION INDUCTION IS PRESENT ACCORDING TO TISSUE TYPES AND INDUCERS, AND THAT CHRONIC INFLAMMATION IS DEEPLY INVOLVED IN METHYLATION INDUCTION. THESE FACTS SUGGEST THAT EPIGENETIC ALTERATIONS OF KEY GENES INVOLVED IN ACQUIRED CHRONIC DISORDERS CAN BE PRESENT IN A SIGNIFICANT FRACTION OF CELLS IN A TISSUE, AND THUS CAN IMPAIR THE FUNCTION OF THE TISSUE. ASSOCIATIONS BETWEEN EPIGENETIC ALTERATIONS AND BEHAVIOR, MEMORY, MENTAL DISORDERS, NEUROLOGICAL DISORDERS, METABOLIC DISORDERS, ALLERGY, AUTOIMMUNE DISORDERS, AND OTHER DISORDERS HAVE BEEN REPORTED. FURTHER RESEARCH IN THE FIELD IS NECESSARY TO CLARIFY THE CAUSAL ROLES OF THESE EPIGENETIC ALTERATIONS IN DISEASE DEVELOPMENT, AND TO APPLY THE FINDINGS TO NEW STRATEGIES OF DISEASE PREVENTION, DIAGNOSIS, AND TREATMENT. 2010 7 6533 42 TRANSCRIPTIONAL REGULATION OF INFLAMMATORY GENES ASSOCIATED WITH SEVERE ASTHMA. THE 10% OF PATIENTS WITH THE MOST SEVERE ASTHMA ARE RESPONSIBLE FOR A LARGE PART OF HEALTHCARE EXPENDITURE AND MORBIDITY. UNDERSTANDING THE PROCESSES INVOLVED IS KEY IF NEW THERAPEUTIC APPROACHES ARE TO BE DEVELOPED. EVIDENCE IS ACCUMULATING THAT CHRONIC DISEASES SUCH AS ASTHMA ARE ASSOCIATED WITH TEMPORAL AND SPATIAL ALTERATIONS IN THE PATTERN OF INFLAMMATORY GENE EXPRESSION WITHIN THE AIRWAYS. EXPRESSION OF THESE GENES CAN BE REGULATED BY TRANSCRIPTIONAL, POSTTRANSCRIPTIONAL, TRANSLATIONAL AND EPIGENETIC MECHANISMS. IT IS WELL ESTABLISHED THAT BINDING OF ACTIVATED TRANSCRIPTION FACTORS TO SPECIFIC INDUCIBLE GENE PROMOTER SITES IS TIGHTLY CONTROLLED BY CHROMATIN STATE AS A RESULT OF HISTONE MODIFICATIONS, PARTICULARLY THE BALANCE BETWEEN HISTONE ACETYLATION AND DEACETYLATION [1]. THE INTERACTION BETWEEN TRANSCRIPTION FACTORS AND THE PROMOTER IS KEY TO THE DIVERSIFICATION OF GENE EXPRESSION IN A TIME DEPENDENT MANNER LEADING TO ALTERED GENE EXPRESSION PROFILES. ALTERATIONS OF THE ACCESSIBILITY OF TRANSCRIPTION FACTORS TO THE DNA CAN HAVE RESIDING EFFECTS UPON GENE TRANSCRIPTION. THIS REVIEW WILL FOCUS ON THE REGULATION OF SEVERAL GROUPS OF KEY GENES WHICH ARE INVOLVED IN CHRONIC AIRWAY INFLAMMATION AND REMODELLING IN ASTHMA DRAWING MAINLY FROM OUR EXPERIENCE OF STUDYING THESE PROCESSES IN AIRWAY SMOOTH MUSCLE CELLS. AN OVERVIEW IS SHOWN IN FIGURE 1. 2011 8 5645 40 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 9 315 37 ALCOHOL, DNA METHYLATION, AND CANCER. CANCER IS ONE OF THE MOST SIGNIFICANT DISEASES ASSOCIATED WITH CHRONIC ALCOHOL CONSUMPTION, AND CHRONIC DRINKING IS A STRONG RISK FACTOR FOR CANCER, PARTICULARLY OF THE UPPER AERODIGESTIVE TRACT, LIVER, COLORECTUM, AND BREAST. SEVERAL FACTORS CONTRIBUTE TO ALCOHOL-INDUCED CANCER DEVELOPMENT (I.E., CARCINOGENESIS), INCLUDING THE ACTIONS OF ACETALDEHYDE, THE FIRST AND PRIMARY METABOLITE OF ETHANOL, AND OXIDATIVE STRESS. HOWEVER, INCREASING EVIDENCE SUGGESTS THAT ABERRANT PATTERNS OF DNA METHYLATION, AN IMPORTANT EPIGENETIC MECHANISM OF TRANSCRIPTIONAL CONTROL, ALSO COULD BE PART OF THE PATHOGENETIC MECHANISMS THAT LEAD TO ALCOHOL-INDUCED CANCER DEVELOPMENT. THE EFFECTS OF ALCOHOL ON GLOBAL AND LOCAL DNA METHYLATION PATTERNS LIKELY ARE MEDIATED BY ITS ABILITY TO INTERFERE WITH THE AVAILABILITY OF THE PRINCIPAL BIOLOGICAL METHYL DONOR, S-ADENOSYLMETHIONINE (SAME), AS WELL AS PATHWAYS RELATED TO IT. SEVERAL MECHANISMS MAY MEDIATE THE EFFECTS OF ALCOHOL ON DNA METHYLATION, INCLUDING REDUCED FOLATE LEVELS AND INHIBITION OF KEY ENZYMES IN ONE-CARBON METABOLISM THAT ULTIMATELY LEAD TO LOWER SAME LEVELS, AS WELL AS INHIBITION OF ACTIVITY AND EXPRESSION OF ENZYMES INVOLVED IN DNA METHYLATION (I.E., DNA METHYLTRANSFERASES). FINALLY, VARIATIONS (I.E., POLYMORPHISMS) OF SEVERAL GENES INVOLVED IN ONE-CARBON METABOLISM ALSO MODULATE THE RISK OF ALCOHOL-ASSOCIATED CARCINOGENESIS. 2013 10 860 41 CHROMATIN MODIFICATIONS DURING REPAIR OF ENVIRONMENTAL EXPOSURE-INDUCED DNA DAMAGE: A POTENTIAL MECHANISM FOR STABLE EPIGENETIC ALTERATIONS. EXPOSURES TO ENVIRONMENTAL TOXICANTS AND TOXINS CAUSE EPIGENETIC CHANGES THAT LIKELY PLAY A ROLE IN THE DEVELOPMENT OF DISEASES ASSOCIATED WITH EXPOSURE. THE MECHANISM BEHIND THESE EXPOSURE-INDUCED EPIGENETIC CHANGES IS CURRENTLY UNKNOWN. ONE COMMONALITY BETWEEN MOST ENVIRONMENTAL EXPOSURES IS THAT THEY CAUSE DNA DAMAGE EITHER DIRECTLY OR THROUGH CAUSING AN INCREASE IN REACTIVE OXYGEN SPECIES, WHICH CAN DAMAGE DNA. LIKE TRANSCRIPTION, DNA DAMAGE REPAIR MUST OCCUR IN THE CONTEXT OF CHROMATIN REQUIRING BOTH HISTONE MODIFICATIONS AND ATP-DEPENDENT CHROMATIN REMODELING. THESE CHROMATIN CHANGES AID IN DNA DAMAGE ACCESSIBILITY AND SIGNALING. SEVERAL PROTEINS AND COMPLEXES INVOLVED IN EPIGENETIC SILENCING DURING BOTH DEVELOPMENT AND CANCER HAVE BEEN FOUND TO BE LOCALIZED TO SITES OF DNA DAMAGE. THE CHROMATIN-BASED RESPONSE TO DNA DAMAGE IS CONSIDERED A TRANSIENT EVENT, WITH CHROMATIN BEING RESTORED TO NORMAL AS DNA DAMAGE REPAIR IS COMPLETED. HOWEVER, IN INDIVIDUALS CHRONICALLY EXPOSED TO ENVIRONMENTAL TOXICANTS OR WITH CHRONIC INFLAMMATORY DISEASE, REPEATED DNA DAMAGE-INDUCED CHROMATIN REARRANGEMENT MAY ULTIMATELY LEAD TO PERMANENT EPIGENETIC ALTERATIONS. UNDERSTANDING THE MECHANISM BEHIND EXPOSURE-INDUCED EPIGENETIC CHANGES WILL ALLOW US TO DEVELOP STRATEGIES TO PREVENT OR REVERSE THESE CHANGES. THIS REVIEW FOCUSES ON EPIGENETIC CHANGES AND DNA DAMAGE INDUCED BY ENVIRONMENTAL EXPOSURES, THE CHROMATIN CHANGES THAT OCCUR AROUND SITES OF DNA DAMAGE, AND HOW THESE TRANSIENT CHROMATIN CHANGES MAY LEAD TO HERITABLE EPIGENETIC ALTERATIONS AT SITES OF CHRONIC EXPOSURE. 2014 11 3738 41 INORGANIC ARSENIC-INDUCED CELLULAR TRANSFORMATION IS COUPLED WITH GENOME WIDE CHANGES IN CHROMATIN STRUCTURE, TRANSCRIPTOME AND SPLICING PATTERNS. BACKGROUND: ARSENIC (AS) EXPOSURE IS A SIGNIFICANT WORLDWIDE ENVIRONMENTAL HEALTH CONCERN. LOW DOSE, CHRONIC ARSENIC EXPOSURE HAS BEEN ASSOCIATED WITH A HIGHER THAN NORMAL RISK OF SKIN, LUNG, AND BLADDER CANCER, AS WELL AS CARDIOVASCULAR DISEASE AND DIABETES. WHILE ARSENIC-INDUCED BIOLOGICAL CHANGES PLAY A ROLE IN DISEASE PATHOLOGY, LITTLE IS KNOWN ABOUT THE DYNAMIC CELLULAR CHANGES RESULTING FROM ARSENIC EXPOSURE AND WITHDRAWAL. RESULTS: IN THESE STUDIES, WE SOUGHT TO UNDERSTAND THE MOLECULAR MECHANISMS BEHIND THE BIOLOGICAL CHANGES INDUCED BY ARSENIC EXPOSURE. A COMPREHENSIVE GLOBAL APPROACH WAS EMPLOYED TO DETERMINE GENOME-WIDE CHANGES TO CHROMATIN STRUCTURE, TRANSCRIPTOME PATTERNS AND SPLICING PATTERNS IN RESPONSE TO CHRONIC LOW DOSE ARSENIC AND ITS SUBSEQUENT WITHDRAWAL. OUR RESULTS SHOW THAT CELLS EXPOSED TO CHRONIC LOW DOSES OF SODIUM ARSENITE HAVE DISTINCT TEMPORAL AND COORDINATED CHROMATIN, GENE EXPRESSION, AND MIRNA CHANGES CONSISTENT WITH DIFFERENTIATION AND ACTIVATION OF MULTIPLE BIOCHEMICAL PATHWAYS. MOST OF THESE TEMPORAL PATTERNS IN GENE EXPRESSION ARE REVERSED WHEN ARSENIC IS WITHDRAWN. HOWEVER, SOME GENE EXPRESSION PATTERNS REMAINED ALTERED, PLAUSIBLY AS A RESULT OF AN ADAPTIVE RESPONSE BY CELLS. ADDITIONALLY, THE CORRELATION OF CHANGES TO GENE EXPRESSION AND CHROMATIN STRUCTURE SOLIDIFY THE ROLE OF CHROMATIN STRUCTURE IN GENE REGULATORY CHANGES DUE TO ARSENITE EXPOSURE. LASTLY, WE SHOW THAT ARSENITE EXPOSURE INFLUENCES GENE REGULATION BOTH AT THE INITIATION OF TRANSCRIPTION AS WELL AS AT THE LEVEL OF SPLICING. CONCLUSIONS: OUR RESULTS SHOW THAT ADAPTATION OF CELLS TO IAS-MEDIATED EMT IS COUPLED TO CHANGES IN CHROMATIN STRUCTURE EFFECTING DIFFERENTIAL TRANSCRIPTIONAL AND SPLICING PATTERNS OF GENES. THESE STUDIES PROVIDE NEW INSIGHTS INTO THE MECHANISM OF IAS-MEDIATED PATHOLOGY, WHICH INCLUDES EPIGENETIC CHROMATIN CHANGES COUPLED WITH CHANGES TO THE TRANSCRIPTOME AND SPLICING PATTERNS OF KEY GENES. 2015 12 712 39 CADMIUM AND ITS EPIGENETIC EFFECTS. CADMIUM (CD) IS A TOXIC, NONESSENTIAL TRANSITION METAL AND CONTRIBUTES A HEALTH RISK TO HUMANS, INCLUDING VARIOUS CANCERS AND CARDIOVASCULAR DISEASES; HOWEVER, UNDERLYING MOLECULAR MECHANISMS REMAIN LARGELY UNKNOWN. CELLS TRANSMIT INFORMATION TO THE NEXT GENERATION VIA TWO DISTINCT WAYS: GENETIC AND EPIGENETIC. CHEMICAL MODIFICATIONS TO DNA OR HISTONE THAT ALTERS THE STRUCTURE OF CHROMATIN WITHOUT CHANGE OF DNA NUCLEOTIDE SEQUENCE ARE KNOWN AS EPIGENETICS. THESE HERITABLE EPIGENETIC CHANGES INCLUDE DNA METHYLATION, POST-TRANSLATIONAL MODIFICATIONS OF HISTONE TAILS (ACETYLATION, METHYLATION, PHOSPHORYLATION, ETC), AND HIGHER ORDER PACKAGING OF DNA AROUND NUCLEOSOMES. APART FROM DNA METHYLTRANSFERASES, HISTONE MODIFICATION ENZYMES SUCH AS HISTONE ACETYLTRANSFERASE, HISTONE DEACETYLASE, AND METHYLTRANSFERASE, AND MICRORNAS (MIRNAS) ALL INVOLVE IN THESE EPIGENETIC CHANGES. RECENT STUDIES INDICATE THAT CD IS ABLE TO INDUCE VARIOUS EPIGENETIC CHANGES IN PLANT AND MAMMALIAN CELLS IN VITRO AND IN VIVO. SINCE ABERRANT EPIGENETICS PLAYS A CRITICAL ROLE IN THE DEVELOPMENT OF VARIOUS CANCERS AND CHRONIC DISEASES, CD MAY CAUSE THE ABOVE-MENTIONED PATHOGENIC RISKS VIA EPIGENETIC MECHANISMS. HERE WE REVIEW THE IN VITRO AND IN VIVO EVIDENCE OF EPIGENETIC EFFECTS OF CD. THE AVAILABLE FINDINGS INDICATE THAT EPIGENETICS OCCURRED IN ASSOCIATION WITH CD INDUCTION OF MALIGNANT TRANSFORMATION OF CELLS AND PATHOLOGICAL PROLIFERATION OF TISSUES, SUGGESTING THAT EPIGENETIC EFFECTS MAY PLAY A ROLE IN CD TOXIC, PARTICULARLY CARCINOGENIC EFFECTS. THE FUTURE OF ENVIRONMENTAL EPIGENOMIC RESEARCH ON CD SHOULD INCLUDE THE ROLE OF EPIGENETICS IN DETERMINING LONG-TERM AND LATE-ONSET HEALTH EFFECTS FOLLOWING CD EXPOSURE. 2012 13 2541 41 EPIGENETICS IN KIDNEY DEVELOPMENT AND RENAL DISEASE. THE STUDY OF EPIGENETICS IS INTIMATELY LINKED AND INSEPARABLE FROM DEVELOPMENTAL BIOLOGY. MANY OF THE GENES THAT IMPRINT EPIGENETIC INFORMATION ON CHROMATIN FUNCTION DURING THE SPECIFICATION OF CELL LINEAGES IN THE DEVELOPING EMBRYO. THESE INCLUDE THE HISTONE METHYLTRANSFERASES AND THEIR COFACTORS OF THE POLYCOMB AND TRITHORAX GENE FAMILIES. HOW HISTONE METHYLATION IS ESTABLISHED AND WHAT REGULATES THE TISSUE AND LOCUS SPECIFICITY OF HISTONE METHYLATION IS AN EMERGING AREA OF RESEARCH. THE EMBRYONIC KIDNEY IS USED AS A MODEL TO UNDERSTAND HOW DNA-BINDING PROTEINS CAN SPECIFY CELL LINEAGES AND HOW SUCH PROTEINS INTERACT DIRECTLY WITH THE HISTONE METHYLATION MACHINERY TO GENERATE A UNIQUE EPIGENOME FOR PARTICULAR TISSUES AND CELL TYPES. IN ADULT TISSUES, HISTONE METHYLATION MARKS MUST BE MAINTAINED FOR NORMAL GENE EXPRESSION PATTERNS. IN CHRONIC AND ACUTE RENAL DISEASE, EPIGENETIC MARKS ARE BEING CHARACTERIZED AND CORRELATED WITH THE ESTABLISHMENT OF METABOLIC MEMORY, IN PART TO EXPLAIN THE PERSISTENCE OF PATHOLOGIES EVEN WHEN OPTIMAL TREATMENT MODALITIES ARE USED. THUS, THE STATE OF THE EPIGENOME IN ADULT CELLS MUST BE CONSIDERED WHEN ATTEMPTING TO ALLEVIATE OR ALTER GENE EXPRESSION PATTERNS IN DISEASE. 2015 14 3659 42 INDUCTION OF EPIGENETIC ALTERATIONS BY CHRONIC INFLAMMATION AND ITS SIGNIFICANCE ON CARCINOGENESIS. CHRONIC INFLAMMATION IS DEEPLY INVOLVED IN DEVELOPMENT OF HUMAN CANCERS, SUCH AS GASTRIC AND LIVER CANCERS. INDUCTION OF CELL PROLIFERATION, PRODUCTION OF REACTIVE OXYGEN SPECIES, AND DIRECT STIMULATION OF EPITHELIAL CELLS BY INFLAMMATION-INDUCING FACTORS HAVE BEEN CONSIDERED AS MECHANISMS INVOLVED. INFLAMMATION-RELATED CANCERS ARE KNOWN FOR THEIR MULTIPLE OCCURRENCES, AND ABERRANT DNA METHYLATION IS KNOWN TO BE PRESENT EVEN IN NONCANCEROUS TISSUES. IMPORTANTLY, FOR SOME CANCERS, THE DEGREE OF ACCUMULATION HAS BEEN DEMONSTRATED TO BE CORRELATED WITH RISK OF DEVELOPING CANCERS. THIS INDICATES THAT INFLAMMATION INDUCES ABERRANT EPIGENETIC ALTERATIONS IN A TISSUE EARLY IN THE PROCESS OF CARCINOGENESIS, AND ACCUMULATION OF SUCH ALTERATIONS FORMS "AN EPIGENETIC FIELD FOR CANCERIZATION." THIS ALSO SUGGESTS THAT INHIBITION OF INDUCTION OF EPIGENETIC ALTERATIONS AND REMOVAL OF THE ACCUMULATED ALTERATIONS ARE NOVEL APPROACHES TO CANCER PREVENTION. DISTURBANCES IN CYTOKINE AND CHEMOKINE SIGNALS AND INDUCTION OF CELL PROLIFERATIONS ARE IMPORTANT MECHANISMS OF HOW INFLAMMATION INDUCES ABERRANT DNA METHYLATION. ABERRANT DNA METHYLATION IS INDUCED IN SPECIFIC GENES, AND GENE EXPRESSION LEVELS, THE PRESENCE OF RNA POLYMERASE II (ACTIVE OR STALLED), AND TRIMETHYLATION OF H3K4 ARE INVOLVED IN THE SPECIFICITY. EXPRESSION OF DNA METHYLTRANSFERASES (DNMTS) IS NOT NECESSARILY INDUCED BY INFLAMMATION, AND LOCAL IMBALANCE BETWEEN DNMTS AND FACTORS THAT PROTECT GENES FROM DNA METHYLATION SEEMS TO BE IMPORTANT. 2010 15 1520 42 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 16 2523 44 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 17 3123 47 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 18 6100 49 THE EMERGING ROLE OF EPIGENETIC MODIFIERS IN REPAIR OF DNA DAMAGE ASSOCIATED WITH CHRONIC INFLAMMATORY DISEASES. AT SITES OF CHRONIC INFLAMMATION EPITHELIAL CELLS ARE EXPOSED TO HIGH LEVELS OF REACTIVE OXYGEN SPECIES (ROS), WHICH CAN CONTRIBUTE TO THE INITIATION AND DEVELOPMENT OF MANY DIFFERENT HUMAN CANCERS. ABERRANT EPIGENETIC ALTERATIONS THAT CAUSE TRANSCRIPTIONAL SILENCING OF TUMOR SUPPRESSOR GENES ARE ALSO IMPLICATED IN MANY DISEASES ASSOCIATED WITH INFLAMMATION, INCLUDING CANCER. HOWEVER, IT IS NOT CLEAR HOW ALTERED EPIGENETIC GENE SILENCING IS INITIATED DURING CHRONIC INFLAMMATION. THE HIGH LEVEL OF ROS AT SITES OF INFLAMMATION IS KNOWN TO INDUCE OXIDATIVE DNA DAMAGE IN SURROUNDING EPITHELIAL CELLS. FURTHERMORE, DNA DAMAGE IS KNOWN TO TRIGGER SEVERAL RESPONSES, INCLUDING RECRUITMENT OF DNA REPAIR PROTEINS, TRANSCRIPTIONAL REPRESSION, CHROMATIN MODIFICATIONS AND OTHER CELL SIGNALING EVENTS. RECRUITMENT OF EPIGENETIC MODIFIERS TO CHROMATIN IN RESPONSE TO DNA DAMAGE RESULTS IN TRANSIENT COVALENT MODIFICATIONS TO CHROMATIN SUCH AS HISTONE UBIQUITINATION, ACETYLATION AND METHYLATION AND DNA METHYLATION. DNA DAMAGE ALSO ALTERS NON-CODING RNA EXPRESSION. ALL OF THESE ALTERATIONS HAVE THE POTENTIAL TO ALTER GENE EXPRESSION AT SITES OF DAMAGE. TYPICALLY, THESE MODIFICATIONS AND GENE TRANSCRIPTION ARE RESTORED BACK TO NORMAL ONCE THE REPAIR OF THE DNA DAMAGE IS COMPLETED. HOWEVER, CHRONIC INFLAMMATION MAY INDUCE SUSTAINED DNA DAMAGE AND DNA DAMAGE RESPONSES THAT RESULT IN THESE TRANSIENT COVALENT CHROMATIN MODIFICATIONS BECOMING MITOTICALLY STABLE EPIGENETIC ALTERATIONS. UNDERSTANDING HOW EPIGENETIC ALTERATIONS ARE INITIATED DURING CHRONIC INFLAMMATION WILL ALLOW US TO DEVELOP PHARMACEUTICAL STRATEGIES TO PREVENT OR TREAT CHRONIC INFLAMMATION-INDUCED CANCER. THIS REVIEW WILL FOCUS ON TYPES OF DNA DAMAGE AND EPIGENETIC ALTERATIONS ASSOCIATED WITH CHRONIC INFLAMMATORY DISEASES, THE TYPES OF DNA DAMAGE AND TRANSIENT COVALENT CHROMATIN MODIFICATIONS INDUCED BY INFLAMMATION AND OXIDATIVE DNA DAMAGE AND HOW THESE MODIFICATIONS MAY RESULT IN EPIGENETIC ALTERATIONS. 2019 19 3837 31 IONIZING RADIATION-INDUCED OXIDATIVE STRESS, EPIGENETIC CHANGES AND GENOMIC INSTABILITY: THE PIVOTAL ROLE OF MITOCHONDRIA. PURPOSE: TO REVIEW THE DATA CONCERNING THE ROLE OF ENDOGENOUSLY GENERATED REACTIVE OXYGEN SPECIES (ROS) IN THE NON-TARGETED IONIZING RADIATION (IR) EFFECTS AND IN DETERMINATION OF THE CELL POPULATION'S FATE, BOTH EARLY AFTER EXPOSURE AND AFTER MANY GENERATIONS. CONCLUSIONS: THE SHORT-TERM AS WELL AS CHRONIC OXIDATIVE STRESS RESPONSES MAINLY ARE PRODUCED DUE TO ROS GENERATION BY THE ELECTRON TRANSPORT CHAIN (ETC) OF THE MITOCHONDRIA AND BY THE CYTOPLASMIC NADPH OXIDASES. WHETHER THE INDUCTION OF THE OXIDATIVE STRESS AND ITS CONSEQUENCES OCCUR OR ARE HAMPERED IN A SINGLE CELL LARGELY DEPENDS ON THE INTERACTION BETWEEN THE NUCLEUS AND THE CELLULAR POPULATION OF SEVERAL HUNDRED OR THOUSANDS OF MITOCHONDRIA THAT ARE GENETICALLY HETEROGENEOUS. HIGH INTRA-MITOCHONDRIAL ROS LEVEL IS DAMAGING THE MITOCHONDRIAL (MT) DNA AND ITS MUTATIONS AFFECT THE EPIGENETIC CONTROL MECHANISMS OF THE NUCLEAR (N) DNA, BY DECREASING THE ACTIVITY OF METHYLTRANSFERASES AND THUS, CAUSING GLOBAL DNA HYPOMETHYLATION. THESE CHANGES ARE TRANSMITTED TO THE PROGENY OF THE IRRADIATED CELLS. THE CHRONIC OXIDATIVE STRESS IS THE MAIN CAUSE OF THE LATE POST-RADIATION EFFECTS, INCLUDING CANCER, AND THIS MAKES IT AN IMPORTANT ADVERSE EFFECT OF EXPOSURE TO IR AND A TARGET FOR RADIOLOGICAL PROTECTION. 2015 20 5756 41 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