1 968 119 CHRONIC NICOTINE EXPOSURE SYSTEMICALLY ALTERS MICRORNA EXPRESSION PROFILES DURING POST-EMBRYONIC STAGES IN CAENORHABDITIS ELEGANS. TOBACCO SMOKING IS ASSOCIATED WITH MANY DISEASES. ADDICTION IS OF THE MOST NOTORIOUS TOBACCO-RELATED SYNDROME AND IS MAINLY ATTRIBUTED TO NICOTINE. IN THIS STUDY, WE EMPLOYED CAENORHABDITIS ELEGANS AS A BIOLOGICAL MODEL TO SYSTEMICALLY INVESTIGATE THE EFFECT OF CHRONIC NICOTINE EXPOSURE ON MICRORNA (MIRNA) EXPRESSION PROFILE AND THEIR REGULATED BIOCHEMICAL PATHWAYS. NICOTINE TREATMENT (20 MICROM AND 20 MM) WAS LIMITED TO THE POST-EMBRYONIC STAGE FROM L1 TO L4 ( APPROXIMATELY 31 H) PERIOD AFTER WHICH WORMS WERE COLLECTED FOR GENOME-WIDE MIRNA PROFILING. OUR RESULTS SHOW THAT NICOTINE SIGNIFICANTLY ALTERED THE EXPRESSION PATTERNS OF 40 MIRNAS. THE EFFECT WAS PROPORTIONAL TO THE NICOTINE DOSE AND WAS EXPECTED TO HAVE AN ADDITIVE, MORE ROBUST RESPONSE. BASED ON PATHWAY ENRICHMENT ANALYSES COUPLED WITH NICOTINE-INDUCED MIRNA PATTERNS, WE INFERRED THAT MIRNAS AS A SYSTEM MEDIATES "REGULATORY HORMESIS", MANIFESTED IN BIPHASIC BEHAVIORAL AND PHYSIOLOGICAL PHENOTYPES. WE PROPOSED A MODEL WHERE NICOTINE ADDICTION IS MEDIATED BY MIRNAS' REGULATION OF FOS-1 AND IS MAINTAINED BY EPIGENETIC FACTORS. THUS, OUR STUDY OFFERS NEW INSIGHTS FOR A BETTER UNDERSTANDING OF THE SENSITIVITY OF EARLY DEVELOPMENTAL STAGES TO NICOTINE. 2014 2 457 38 APPLYING A MULTISCALE SYSTEMS BIOLOGY APPROACH TO STUDY THE EFFECT OF CHRONIC LOW-DOSE EXPOSURE TO URANIUM IN RAT KIDNEYS. PURPOSE: TO EXAMINE THE EFFECTS OF LOW-DOSE EXPOSURE TO URANIUM WITH A SYSTEMS BIOLOGY APPROACH, A MULTISCALE HIGH-THROUGHPUT MULTI-OMICS ANALYSIS WAS APPLIED WITH A PROTOCOL FOR CHRONIC EXPOSURE TO THE RAT KIDNEY. METHODS: MALE AND FEMALE RATS WERE CONTAMINATED FOR NINE MONTHS THROUGH THEIR DRINKING WATER WITH A NONTOXIC SOLUTION OF URANYL NITRATE. A MULTISCALE APPROACH ENABLED CLINICAL MONITORING ASSOCIATED WITH METABOLOMIC AND TRANSCRIPTOMIC (MRNA AND MICRORNA) ANALYSES. RESULTS: A SEX-INTERACTION EFFECT WAS OBSERVED IN THE KIDNEY, URINE, AND PLASMA METABOLOMES OF CONTAMINATED RATS. MOREOVER, URINE AND KIDNEY METABOLIC PROFILES CORRELATED AND CONFIRMED THAT THE PRIMARY DYSREGULATED METABOLISMS ARE THOSE OF NICOTINATE-NICOTINAMIDE AND OF UNSATURATED FATTY ACID BIOSYNTHESIS. UPSTREAM OF THE METABOLIC PATHWAYS, TRANSCRIPTOMIC PROFILES OF THE KIDNEY REVEAL GENE ACTIVITY FOCUSED ON GENE REGULATION MECHANISMS, CELL SIGNALING, CELL STRUCTURE, DEVELOPMENTAL PROCESSES, AND CELL PROLIFERATION. EXAMINATION OF EPIGENETIC POST-TRANSCRIPTIONAL GENE REGULATION PROCESSES SHOWED SIGNIFICANT DYSREGULATION OF 70 MICRO-RNAS. THE MULTI-OMICS APPROACH HIGHLIGHTED THE ACTIVITIES OF THE CELLS' BIOLOGICAL PROCESSES ON MULTIPLE SCALES THROUGH ANALYSIS OF GENE EXPRESSION, CONFIRMED BY CHANGES OBSERVED IN THE METABOLOME. CONCLUSION: OUR RESULTS SHOWED CHANGES IN MULTI-OMIC PROFILES OF RATS EXPOSED TO LOW DOSES OF URANIUM CONTAMINATION, COMPARED WITH CONTROLS. THESE CHANGES INVOLVED GENE EXPRESSION AS WELL AS MODIFICATIONS IN THE TRANSCRIPTOME AND THE METABOLOME. THE METABOLOMIC PROFILE CONFIRMED THAT THE MAIN MOLECULAR TARGETS OF URANIUM IN KIDNEY CELLS ARE THE METABOLISM OF NICOTINATE-NICOTINAMIDE AND THE BIOSYNTHESIS OF UNSATURATED FATTY ACIDS. ADDITIONALLY, GENE EXPRESSION ANALYSIS SHOWED THAT THE METABOLISM OF FATTY ACIDS IS TARGETED BY PROCESSES ASSOCIATED WITH CELL FUNCTION. THESE RESULTS DEMONSTRATE THAT MULTISCALE SYSTEMS BIOLOGY IS USEFUL IN ELUCIDATING THE MOST DISCRIMINATIVE PATHWAYS FROM GENOMIC TO METABOLOMIC LEVELS FOR ASSESSING THE BIOLOGICAL IMPACT OF THIS LOW-LEVEL ENVIRONMENTAL EXPOSURE, I.E. THE EXPOSOME. 2019 3 4093 30 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 2022 39 EPIGENETIC CHANGES ASSOCIATED WITH DISEASE PROGRESSION IN A MOUSE MODEL OF CHILDHOOD ALLERGIC ASTHMA. DEVELOPMENT OF ASTHMA IN CHILDHOOD IS LINKED TO VIRAL INFECTIONS OF THE LOWER RESPIRATORY TRACT IN EARLY LIFE, WITH SUBSEQUENT CHRONIC EXPOSURE TO ALLERGENS. PROGRESSION TO PERSISTENT ASTHMA IS ASSOCIATED WITH A TH2-BIASED IMMUNOLOGICAL RESPONSE AND STRUCTURAL REMODELLING OF THE AIRWAYS. THE UNDERLYING MECHANISMS ARE UNCLEAR, BUT COULD INVOLVE EPIGENETIC CHANGES. TO INVESTIGATE THIS, WE EMPLOYED A RECENTLY DEVELOPED MOUSE MODEL IN WHICH SELF-LIMITED NEONATAL INFECTION WITH A PNEUMOVIRUS, FOLLOWED BY SENSITISATION TO OVALBUMIN VIA THE RESPIRATORY TRACT AND LOW-LEVEL CHRONIC CHALLENGE WITH AEROSOLISED ANTIGEN, LEADS TO DEVELOPMENT OF AN ASTHMATIC PHENOTYPE. WE ASSESSED EXPRESSION OF MICRORNA BY CELLS IN THE PROXIMAL AIRWAYS, COMPARING CHANGES OVER THE PERIOD OF DISEASE PROGRESSION, AND USED TARGET PREDICTION DATABASES TO IDENTIFY GENES LIKELY TO BE UP- OR DOWNREGULATED AS A CONSEQUENCE OF ALTERED REGULATION OF MICRORNA. IN PARALLEL, WE ASSESSED DNA METHYLATION IN PULMONARY CD4(+) T CELLS. WE FOUND THAT A LIMITED NUMBER OF MICRORNAS EXHIBITED MARKED UP- OR DOWNREGULATION FOLLOWING EARLY-LIFE INFECTION AND SENSITISATION, FOR MANY OF WHICH THE LEVELS OF EXPRESSION WERE FURTHER CHANGED FOLLOWING CHRONIC CHALLENGE WITH THE SENSITIZING ANTIGEN. TARGETS OF THESE MICRORNAS INCLUDED GENES INVOLVED IN IMMUNE OR INFLAMMATORY RESPONSES (E.G. GATA3, KITL) AND IN TISSUE REMODELLING (E.G. IGF1, TGFBR1), AS WELL AS GENES FOR VARIOUS TRANSCRIPTION FACTORS AND SIGNALLING PROTEINS. IN PULMONARY CD4(+) T CELLS, THERE WAS SIGNIFICANT DEMETHYLATION AT PROMOTER SITES FOR INTERLEUKIN-4 AND INTERFERON-GAMMA, THE LATTER INCREASING FOLLOWING CHRONIC CHALLENGE. WE CONCLUDE THAT, IN THIS MODEL, PROGRESSION TO AN ASTHMATIC PHENOTYPE IS LINKED TO EPIGENETIC REGULATION OF GENES ASSOCIATED WITH INFLAMMATION AND STRUCTURAL REMODELLING, AND WITH T-CELL COMMITMENT TO A TH2 IMMUNOLOGICAL RESPONSE. EPIGENETIC CHANGES ASSOCIATED WITH THIS PATTERN OF GENE ACTIVATION MIGHT PLAY A ROLE IN THE DEVELOPMENT OF CHILDHOOD ASTHMA. 2013 5 3738 42 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 6 4292 40 MICRORNA PROFILES OF MATERNAL AND NEONATAL ENDOTHELIAL PROGENITOR CELLS IN PREECLAMPSIA. PREECLAMPSIA IS ASSOCIATED WITH AN INCREASED CARDIOVASCULAR MORBIDITY OF MOTHER AND OFFSPRING, THUS CONTRIBUTING TO A SUBSTANTIAL BURDEN IN WOMEN AND CHILDREN'S HEALTH. IT HAS BEEN PROVEN THAT ENDOTHELIAL PROGENITOR CELL (EPC) NUMBERS AND FUNCTIONAL CHARACTERISTICS ARE IMPAIRED IN CARDIOVASCULAR DISEASE AND PREECLAMPSIA, ALTHOUGH CAUSATIVE FACTORS FOR THE LATTER HAVE REMAINED ELUSIVE. MICRORNA (MIRNA) MODIFICATIONS ARE A POTENTIAL MECHANISM THROUGH WHICH EXPOSURE TO AN ALTERED ENVIRONMENT TRANSLATES INTO THE DEVELOPMENT OF CHRONIC DISEASE. IN THIS STUDY, WE EXAMINED WHETHER DEVELOPMENT OF PREECLAMPSIA CORRESPONDS TO ALTERATIONS OF MIRNAS IN MATERNAL- AND CORD-BLOOD-DERIVED EPC. TO TEST THIS END, WE ANALYZED MATERNAL AND NEONATAL MIRNAS VIA RNA SEQUENCING FROM ENDOTHELIAL CELLS OF PREECLAMPTIC AND HEALTHY CONTROLS IN DIFFERENT CELL CULTURE PASSAGES. WE WERE ABLE TO DEMONSTRATE DIFFERENTIALLY REPRESENTED MIRNAS IN ALL GROUPS. HSA-MIR-1270 SHOWED SIGNIFICANTLY DIFFERENT LEVELS IN CORD BLOOD EPC FROM PREECLAMPSIA VERSUS CONTROL AND WAS NEGATIVELY CORRELATED WITH MRNA LEVELS OF ITS PREDICTED TARGETS ANGPTL7 AND TFRC. TRANSFECTION WITH AN HSA-MIR-1270 INHIBITOR DECREASED THE TUBE FORMATION CAPACITY AND CHEMOTACTIC MOTILITY BUT DID NOT CHANGE PROLIFERATION IN VITRO. TARGET PREDICTIONS AND GENE SET ENRICHMENT ANALYSES IDENTIFIED ALTERNATIVE SPLICING AS A SIGNIFICANTLY ENRICHED PATHWAY FOR HSA-MIR-1270. THE TOP MIRNAS IN THREE OTHER GROUPS WERE PREDICTED TO TARGET TRANSCRIPTIONAL AND DEVELOPMENTAL PATHWAYS. HERE, WE SHOWED FOR THE FIRST TIME SIGNIFICANTLY DIFFERENT LEVELS OF MIRNAS AND DIFFERENTLY REPRESENTED MRNA LEVELS OF PREDICTED TARGET GENES IN EPC DERIVED FROM PREECLAMPSIA. UNDERSTANDING THE EFFECTS OF PREECLAMPSIA ON THE EPIGENETIC MECHANISMS OF EPC WILL BE CRUCIAL AND MAY PROVIDE INITIAL INSIGHTS FOR FURTHER EVALUATION OF THE BENEFITS OF THERAPIES TARGETING THIS CELL POPULATION. 2021 7 2119 27 EPIGENETIC HISTONE MODIFICATION REGULATES DEVELOPMENTAL LEAD EXPOSURE INDUCED HYPERACTIVITY IN RATS. LEAD (PB) EXPOSURE WAS COMMONLY CONSIDERED AS A HIGH ENVIRONMENTAL RISK FACTOR FOR THE DEVELOPMENT OF ATTENTION-DEFICIT/HYPERACTIVITY DISORDER (ADHD). HOWEVER, THE MOLECULAR BASIS OF THIS PATHOLOGICAL PROCESS STILL REMAINS ELUSIVE. IN LIGHT OF THE ROLE OF EPIGENETICS IN MODULATING THE NEUROLOGICAL DISEASE AND THE CAUSATIVE ENVIRONMENT, THE ALTERATIONS OF HISTONE MODIFICATIONS IN THE HIPPOCAMPUS OF RATS EXPOSED BY VARIOUS DOSES OF LEAD, ALONG WITH CONCOMITANT BEHAVIORAL DEFICITS, WERE INVESTIGATED IN THIS STUDY. ACCORDING TO THE FREE AND FORCED OPEN FIELD TEST, THERE SHOWED THAT IN A DOSAGE-DEPENDENT MANNER, LEAD EXPOSURE COULD RESULT IN THE INCREASED LOCOMOTOR ACTIVITY OF RATS, THAT IS, HYPERACTIVITY: A SUBTYPE OF ADHD. WESTERN BLOTTING ASSAYS REVEALED THAT THE LEVELS OF HISTONE ACETYLATION INCREASED SIGNIFICANTLY IN THE HIPPOCAMPUS BY CHRONIC LEAD EXPOSURE, WHILE NO DRAMATIC CHANGES WERE DETECTED IN TERMS OF EXPRESSION YIELDS OF ADHD-RELATED DOPAMINERGIC PROTEINS, INDICATING THAT HISTONE ACETYLATION PLAYS ESSENTIAL ROLES IN THIS TOXICANT-INVOLVED PATHOGENESIS. IN ADDITION, THE INCREASED LEVEL OF HISTONE ACETYLATION MIGHT BE ATTRIBUTED TO THE ENZYMATIC ACTIVITY OF P300, A TYPICAL HISTONE ACETYLTRANSFERASE, AS THE TRANSCRIPTIONAL LEVEL OF P300 WAS SIGNIFICANTLY INCREASED UPON HIGHER-DOSE PB EXPOSURE. IN SUMMARY, THIS STUDY FIRST DISCOVERED THE EPIGENETIC MECHANISM BRIDGING THE ENVIRONMENTAL INFLUENCE (PB) AND THE DISEASE ITSELF (ADHD) IN THE HISTONE MODIFICATION LEVEL, PAVING THE WAY FOR THE COMPREHENSIVE UNDERSTANDING OF ADHD'S ETIOLOGY AND IN FURTHER STEPS, ESTABLISHING THE THERAPY STRATEGY OF THIS WIDESPREAD NEUROLOGICAL DISORDER. 2014 8 3652 31 INDIVIDUAL DNA METHYLATION PATTERN SHIFTS IN NANOPARTICLES-EXPOSED WORKERS ANALYZED IN FOUR CONSECUTIVE YEARS. A DNA METHYLATION PATTERN REPRESENTS AN ORIGINAL PLAN OF THE FUNCTION SETTINGS OF INDIVIDUAL CELLS AND TISSUES. THE BASIC STRATEGIES OF ITS DEVELOPMENT AND CHANGES DURING THE HUMAN LIFETIME ARE KNOWN, BUT THE DETAILS RELATED TO ITS MODIFICATION OVER THE YEARS ON AN INDIVIDUAL BASIS HAVE NOT YET BEEN STUDIED. MOREOVER, CURRENT EVIDENCE SHOWS THAT ENVIRONMENTAL EXPOSURE COULD GENERATE CHANGES IN DNA METHYLATION SETTINGS AND, SUBSEQUENTLY, THE FUNCTION OF GENES. IN THIS STUDY, WE ANALYZED THE EFFECT OF CHRONIC EXPOSURE TO NANOPARTICLES (NP) IN OCCUPATIONALLY EXPOSED WORKERS REPEATEDLY SAMPLED IN FOUR CONSECUTIVE YEARS (2016-2019). A DETAILED METHYLATION PATTERN ANALYSIS OF 14 PERSONS (10 EXPOSED AND 4 CONTROLS) WAS PERFORMED ON AN INDIVIDUAL BASIS. A MICROARRAY-BASED APPROACH USING CHIPS, ALLOWING THE ASSESSMENT OF MORE THAN 850 K CPG LOCI, WAS USED. INDIVIDUAL DNA METHYLATION PATTERNS WERE COMPARED BY PRINCIPAL COMPONENT ANALYSIS (PCA). THE RESULTS SHOW THE SHIFT IN DNA METHYLATION PATTERNS IN INDIVIDUAL YEARS IN ALL THE EXPOSED AND CONTROL SUBJECTS. THE OVERALL RANGE OF DIFFERENCES VARIED BETWEEN THE YEARS IN INDIVIDUAL PERSONS. THE DIFFERENCES BETWEEN THE FIRST AND LAST YEAR OF EXAMINATION (A THREE-YEAR TIME PERIOD) SEEM TO BE CONSISTENTLY GREATER IN THE NP-EXPOSED SUBJECTS IN COMPARISON WITH THE CONTROLS. THE SELECTED 14 MOST DIFFERENTLY METHYLATED CG LOCI WERE RELATIVELY STABLE IN THE CHRONICALLY EXPOSED SUBJECTS. IN SUMMARY, THE SPECIFIC TYPE OF LONG-TERM EXPOSURE CAN CONTRIBUTE TO THE FIXING OF RELEVANT EPIGENETIC CHANGES RELATED TO A SPECIFIC ENVIRONMENT AS, E.G., NP INHALATION. 2021 9 1508 39 DNA METHYLATION AND MRNA AND MICRORNA EXPRESSION OF SLE CD4+ T CELLS CORRELATE WITH DISEASE PHENOTYPE. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IS AN AUTOIMMUNE DISEASE WELL KNOWN FOR ITS CLINICAL HETEROGENEITY, AND ITS ETIOLOGY SECONDARY TO A CROSS-TALK INVOLVING GENETIC PREDISPOSITION AND ENVIRONMENTAL STIMULI. ALTHOUGH GENOME-WIDE ANALYSIS HAS CONTRIBUTED GREATLY TO OUR UNDERSTANDING OF THE GENETIC BASIS OF SLE, THERE IS INCREASING EVIDENCE FOR A ROLE OF EPIGENETICS. INDEED, RECENT DATA HAVE DEMONSTRATED THAT IN PATIENTS WITH SLE, THERE ARE STRIKING ALTERATIONS OF DNA METHYLATION, HISTONE MODIFICATIONS, AND DEREGULATED MICRORNA EXPRESSION, THE SUM OF WHICH CONTRIBUTE TO OVER-EXPRESSION OF SELECT AUTOIMMUNE-RELATED GENES AND LOSS OF TOLERANCE. TO ADDRESS THIS ISSUE AT THE LEVEL OF CLINICAL PHENOTYPE, WE PERFORMED DNA METHYLATION, MRNA AND MICRORNA EXPRESSION SCREENING USING HIGH-THROUGHPUT SEQUENCING OF PURIFIED CD4+ T CELLS FROM PATIENTS WITH SLE, COMPARED TO AGE AND SEX MATCHED CONTROLS. IN PARTICULAR, WE STUDIED 42 PATIENTS WITH SLE AND DIVIDED THIS GROUP INTO THREE CLINICAL PHENOTYPES: A) THE PRESENCE OF SKIN LESIONS WITHOUT SIGNS OF SYSTEMIC PATHOLOGY; B) SKIN LESIONS BUT ALSO CHRONIC RENAL PATHOLOGY; AND C) SKIN LESIONS, CHRONIC RENAL PATHOLOGY AND POLYARTICULAR DISEASE. INTERESTINGLY, AND AS EXPECTED, SEQUENCING DATA REVEALED CHANGES IN DNA METHYLATION IN SLE COMPARED TO CONTROLS. HOWEVER, AND MORE IMPORTANTLY, ALTHOUGH THERE WERE COMMON METHYLATION CHANGES FOUND IN ALL GROUPS OF SLE COMPARED TO CONTROLS, THERE WAS SPECIFIC DNA METHYLATION CHANGES THAT CORRELATED WITH CLINICAL PHENOTYPE. THESE INCLUDED CHANGES IN THE NOVEL KEY TARGET GENES NLRP2, CD300LB AND S1PR3, AS WELL AS CHANGES IN THE CRITICAL PATHWAYS, INCLUDING THE ADHERENS JUNCTION AND LEUKOCYTE TRANSENDOTHELIAL MIGRATION. WE ALSO NOTED THAT A SIGNIFICANT PROPORTION OF GENES UNDERGOING DNA METHYLATION CHANGES WERE INVERSELY CORRELATED WITH GENE EXPRESSION AND THAT MIRNA SCREENING REVEALED THE EXISTENCE OF SUBSETS WITH CHANGES IN EXPRESSION. INTEGRATED ANALYSIS OF THIS DATA HIGHLIGHTS SPECIFIC SETS OF MIRNAS CONTROLLED BY DNA METHYLATION, AND GENES THAT ARE ALTERED BY METHYLATION AND TARGETED BY MIRNAS. IN CONCLUSION, OUR FINDINGS SUGGEST SELECT EPIGENETIC MECHANISMS THAT CONTRIBUTE TO CLINICAL PHENOTYPES AND FURTHER SHED LIGHT ON A NEW VENUE FOR BASIC SLE RESEARCH. 2014 10 2909 32 GENE EXPRESSION PROFILING IN FIBROMYALGIA INDICATES AN AUTOIMMUNE ORIGIN OF THE DISEASE AND OPENS NEW AVENUES FOR TARGETED THERAPY. FIBROMYALGIA IS A CHRONIC DISORDER CHARACTERIZED BY WIDESPREAD PAIN AND BY SEVERAL NON-PAIN SYMPTOMS. AUTOIMMUNITY, SMALL FIBER NEUROPATHY AND NEUROINFLAMMATION HAVE BEEN SUGGESTED TO BE INVOLVED IN THE PATHOGENESIS OF THE DISEASE. WE HAVE INVESTIGATED THE GENE EXPRESSION PROFILE IN PERIPHERAL BLOOD MONONUCLEAR CELLS OBTAINED FROM TEN PATIENTS AND TEN HEALTHY SUBJECTS. OF THE 545,500 TRANSCRIPTS ANALYZED, 1673 RESULTED MODULATED IN FIBROMYALGIC PATIENTS. THE MAJORITY OF THESE GENES ARE INVOLVED IN BIOLOGICAL PROCESSES AND PATHWAYS LINKED TO THE CLINICAL MANIFESTATIONS OF THE DISEASE. MOREOVER, GENES INVOLVED IN IMMUNOLOGICAL PATHWAYS CONNECTED TO INTERLEUKIN-17 AND TO TYPE I INTERFERON SIGNATURES WERE ALSO MODULATED, SUGGESTING THAT AUTOIMMUNITY PLAYS A ROLE IN THE DISEASE. WE THEN AIMED AT IDENTIFYING DIFFERENTIALLY EXPRESSED LONG NON-CODING RNAS (LNCRNAS) FUNCTIONALLY CONNECTED TO MODULATED GENES BOTH DIRECTLY AND VIA MICRORNA TARGETING. ONLY TWO LNCRNAS OF THE 298 FOUND MODULATED IN PATIENTS, WERE ABLE TO TARGET THE MOST HIGHLY CONNECTED GENES IN THE FIBROMYALGIA INTERACTOME, SUGGESTING THEIR INVOLVEMENT IN CRUCIAL GENE REGULATION. OUR GENE EXPRESSION DATA WERE CONFIRMED BY REAL TIME PCR, BY AUTOANTIBODY TESTING, DETECTION OF SOLUBLE MEDIATORS AND TH-17 POLARIZATION IN A VALIDATION COHORT OF 50 PATIENTS. OUR RESULTS INDICATE THAT GENETIC AND EPIGENETIC MECHANISMS AS WELL AS AUTOIMMUNITY PLAY A PIVOTAL ROLE IN THE PATHOGENESIS OF FIBROMYALGIA. 2020 11 5645 31 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 12 1503 27 DNA METHYLATION AND GENE EXPRESSION DIFFERENCES IN CHILDREN CONCEIVED IN VITRO OR IN VIVO. EPIDEMIOLOGICAL DATA INDICATE THAT CHILDREN CONCEIVED IN VITRO HAVE A GREATER RELATIVE RISK OF LOW BIRTH-WEIGHT, MAJOR AND MINOR BIRTH DEFECTS, AND RARE DISORDERS INVOLVING IMPRINTED GENES, SUGGESTING THAT EPIGENETIC CHANGES MAY BE ASSOCIATED WITH ASSISTED REPRODUCTION. WE EXAMINED DNA METHYLATION AT MORE THAN 700 GENES (1536 CPG SITES) IN PLACENTA AND CORD BLOOD AND MEASURED GENE EXPRESSION LEVELS OF A SUBSET OF GENES THAT DIFFERED IN METHYLATION LEVELS BETWEEN CHILDREN CONCEIVED IN VITRO VERSUS IN VIVO. OUR RESULTS SUGGEST THAT IN VITRO CONCEPTION IS ASSOCIATED WITH LOWER MEAN METHYLATION AT CPG SITES IN PLACENTA AND HIGHER MEAN METHYLATION AT CPG SITES IN CORD BLOOD. WE ALSO FIND THAT IN VITRO CONCEPTION-ASSOCIATED DNA METHYLATION DIFFERENCES ARE ASSOCIATED WITH GENE EXPRESSION DIFFERENCES AT BOTH IMPRINTED AND NON-IMPRINTED GENES. THE RANGE OF INTER-INDIVIDUAL VARIATION IN GENE EXPRESSION OF THE IN VITRO AND IN VIVO GROUPS OVERLAPS SUBSTANTIALLY BUT SOME INDIVIDUALS FROM THE IN VITRO GROUP DIFFER FROM THE IN VIVO GROUP MEAN BY MORE THAN TWO STANDARD DEVIATIONS. SEVERAL OF THE GENES WHOSE EXPRESSION DIFFERS BETWEEN THE TWO GROUPS HAVE BEEN IMPLICATED IN CHRONIC METABOLIC DISORDERS, SUCH AS OBESITY AND TYPE II DIABETES. THESE FINDINGS SUGGEST THAT THERE MAY BE EPIGENETIC DIFFERENCES IN THE GAMETES OR EARLY EMBRYOS DERIVED FROM COUPLES UNDERGOING TREATMENT FOR INFERTILITY. ALTERNATIVELY, ASSISTED REPRODUCTION TECHNOLOGY MAY HAVE AN EFFECT ON GLOBAL PATTERNS OF DNA METHYLATION AND GENE EXPRESSION. IN EITHER CASE, THESE DIFFERENCES OR CHANGES MAY AFFECT LONG-TERM PATTERNS OF GENE EXPRESSION. 2009 13 1269 32 CYTOSINE METHYLATION CHANGES IN ENHANCER REGIONS OF CORE PRO-FIBROTIC GENES CHARACTERIZE KIDNEY FIBROSIS DEVELOPMENT. BACKGROUND: ONE IN ELEVEN PEOPLE IS AFFECTED BY CHRONIC KIDNEY DISEASE, A CONDITION CHARACTERIZED BY KIDNEY FIBROSIS AND PROGRESSIVE LOSS OF KIDNEY FUNCTION. EPIDEMIOLOGICAL STUDIES INDICATE THAT ADVERSE INTRAUTERINE AND POSTNATAL ENVIRONMENTS HAVE A LONG-LASTING ROLE IN CHRONIC KIDNEY DISEASE DEVELOPMENT. EPIGENETIC INFORMATION REPRESENTS A PLAUSIBLE CARRIER FOR MEDIATING THIS PROGRAMMING EFFECT. HERE WE DEMONSTRATE THAT GENOME-WIDE CYTOSINE METHYLATION PATTERNS OF HEALTHY AND CHRONIC KIDNEY DISEASE TUBULE SAMPLES OBTAINED FROM PATIENTS SHOW SIGNIFICANT DIFFERENCES. RESULTS: WE IDENTIFY DIFFERENTIALLY METHYLATED REGIONS AND VALIDATE THESE IN A LARGE REPLICATION DATASET. THE DIFFERENTIALLY METHYLATED REGIONS ARE RARELY OBSERVED ON PROMOTERS, BUT MOSTLY OVERLAP WITH PUTATIVE ENHANCER REGIONS, AND THEY ARE ENRICHED IN CONSENSUS BINDING SEQUENCES FOR IMPORTANT RENAL TRANSCRIPTION FACTORS. THIS INDICATES THEIR IMPORTANCE IN GENE EXPRESSION REGULATION. A CORE SET OF GENES THAT ARE KNOWN TO BE RELATED TO KIDNEY FIBROSIS, INCLUDING GENES ENCODING COLLAGENS, SHOW CYTOSINE METHYLATION CHANGES CORRELATING WITH DOWNSTREAM TRANSCRIPT LEVELS. CONCLUSIONS: OUR REPORT RAISES THE POSSIBILITY THAT EPIGENETIC DYSREGULATION PLAYS A ROLE IN CHRONIC KIDNEY DISEASE DEVELOPMENT VIA INFLUENCING CORE PRO-FIBROTIC PATHWAYS AND CAN AID THE DEVELOPMENT OF NOVEL BIOMARKERS AND FUTURE THERAPEUTICS. 2013 14 5894 32 T CELL EPIGENETIC REMODELING AND ACCELERATED EPIGENETIC AGING ARE LINKED TO LONG-TERM IMMUNE ALTERATIONS IN CHILDHOOD CANCER SURVIVORS. BACKGROUND: CANCER TREATMENTS HAVE SUBSTANTIALLY IMPROVED CHILDHOOD CANCER SURVIVAL BUT ARE ACCOMPANIED BY LONG-TERM COMPLICATIONS, NOTABLY CHRONIC INFLAMMATORY DISEASES. WE HYPOTHESIZE THAT CANCER TREATMENTS COULD LEAD TO LONG-TERM EPIGENETIC CHANGES IN IMMUNE CELLS, RESULTING IN INCREASED PREVALENCE OF INFLAMMATORY DISEASES IN CANCER SURVIVORS. RESULTS: TO TEST THIS HYPOTHESIS, WE ESTABLISHED THE EPIGENETIC AND TRANSCRIPTOMIC PROFILES OF IMMUNE CELLS FROM 44 CHILDHOOD CANCER SURVIVORS (CCS, > 16 YEARS OLD) ON FULL REMISSION (> 5 YEARS) WHO HAD RECEIVED CHEMOTHERAPY ALONE OR IN COMBINATION WITH TOTAL BODY IRRADIATION (TBI) AND HEMATOPOIETIC STEM CELL TRANSPLANT (HSCT). WE FOUND THAT MORE THAN 10 YEARS POST-TREATMENT, CCS TREATED WITH TBI/HSCT SHOWED AN ALTERED DNA METHYLATION SIGNATURE IN T CELL, PARTICULARLY AT GENES CONTROLLING IMMUNE AND INFLAMMATORY PROCESSES AND OXIDATIVE STRESS. DNA METHYLATION REMODELING IN T CELL WAS PARTIALLY ASSOCIATED WITH CHRONIC EXPRESSION CHANGES OF NEARBY GENES, INCREASED FREQUENCY OF TYPE 1 CYTOKINE-PRODUCING T CELL, ELEVATED SYSTEMIC LEVELS OF THESE CYTOKINES, AND OVER-ACTIVATION OF RELATED SIGNALING PATHWAYS. SURVIVORS EXPOSED TO TBI/HSCT WERE FURTHER CHARACTERIZED BY AN EPIGENETIC-AGING-SIGNATURE OF T CELL CONSISTENT WITH ACCELERATED EPIGENETIC AGING. TO INVESTIGATE THE POTENTIAL CONTRIBUTION OF IRRADIATION TO THESE CHANGES, WE ESTABLISHED TWO CELL CULTURE MODELS. WE IDENTIFIED THAT RADIATION PARTIALLY RECAPITULATED THE IMMUNE CHANGES OBSERVED IN SURVIVORS THROUGH A BYSTANDER EFFECT THAT COULD BE MEDIATED BY CIRCULATING FACTORS. CONCLUSION: CANCER TREATMENTS, IN PARTICULAR TBI/HSCT, ARE ASSOCIATED WITH LONG-TERM IMMUNE DISTURBANCES. WE PROPOSE THAT EPIGENETIC REMODELING OF IMMUNE CELLS FOLLOWING CANCER THERAPY AUGMENTS INFLAMMATORY- AND AGE-RELATED DISEASES, INCLUDING METABOLIC COMPLICATIONS, IN CHILDHOOD CANCER SURVIVORS. 2018 15 904 38 CHRONIC EXPOSURE TO CADMIUM INDUCES DIFFERENTIAL METHYLATION IN MICE SPERMATOZOA. CADMIUM EXPOSURE IS UBIQUITOUS AND HAS BEEN LINKED TO DISEASES INCLUDING CANCERS AND REPRODUCTIVE DEFECTS. SINCE CADMIUM IS NONMUTAGENIC, IT IS THOUGHT TO EXERT ITS GENE DYSREGULATORY EFFECTS THROUGH EPIGENETIC REPROGRAMMING. SEVERAL STUDIES HAVE IMPLICATED GERMLINE EXPOSURE TO CADMIUM IN DEVELOPMENTAL REPROGRAMMING. HOWEVER, MOST OF THESE STUDIES HAVE FOCUSED ON MATERNAL EXPOSURE, WHILE THE IMPACT ON SPERM FERTILITY AND DISEASE SUSCEPTIBILITY HAS RECEIVED LESS ATTENTION. IN THIS STUDY, WE USED REDUCED REPRESENTATION BISULFITE SEQUENCING TO COMPREHENSIVELY INVESTIGATE THE IMPACT OF CHRONIC CADMIUM EXPOSURE ON MOUSE SPERMATOZOA DNA METHYLATION. ADULT MALE C57BL/J6 MICE WERE PROVIDED WATER WITH OR WITHOUT CADMIUM CHLORIDE FOR 9 WEEKS. SPERM, TESTES, LIVER, AND KIDNEY TISSUES WERE COLLECTED AT THE END OF THE TREATMENT PERIOD. CADMIUM EXPOSURE WAS CONFIRMED THROUGH GENE EXPRESSION ANALYSIS OF METALLOTHIONEIN-1 AND 2, 2 WELL-KNOWN CADMIUM-INDUCED GENES. ANALYSIS OF SPERM DNA METHYLATION CHANGES REVEALED 1788 DIFFERENTIALLY METHYLATED SITES PRESENT AT REGULATORY REGIONS IN SPERM OF MICE EXPOSED TO CADMIUM COMPARED WITH VEHICLE (CONTROL) MICE. FURTHERMORE, MOST OF THESE DIFFERENTIAL METHYLATION CHANGES POSITIVELY CORRELATED WITH CHANGES IN GENE EXPRESSION AT BOTH THE TRANSCRIPTION INITIATION STAGE AS WELL AS THE SPLICING LEVELS. INTERESTINGLY, THE GENES TARGETED BY CADMIUM EXPOSURE ARE INVOLVED IN SEVERAL CRITICAL DEVELOPMENTAL PROCESSES. OUR RESULTS PRESENT A COMPREHENSIVE ANALYSIS OF THE SPERM METHYLOME IN RESPONSE TO CHRONIC CADMIUM EXPOSURE. THESE DATA, THEREFORE, HIGHLIGHT A FOUNDATIONAL FRAMEWORK TO STUDY GENE EXPRESSION PATTERNS THAT MAY AFFECT FERTILITY IN THE EXPOSED INDIVIDUAL AS WELL AS THEIR OFFSPRING, THROUGH PATERNAL INHERITANCE. 2021 16 2920 34 GENE-SET ANALYSIS IS SEVERELY BIASED WHEN APPLIED TO GENOME-WIDE METHYLATION DATA. MOTIVATION: DNA METHYLATION IS AN EPIGENETIC MARK THAT CAN STABLY REPRESS GENE EXPRESSION. BECAUSE OF ITS BIOLOGICAL AND CLINICAL SIGNIFICANCE, SEVERAL METHODS HAVE BEEN DEVELOPED TO COMPARE GENOME-WIDE PATTERNS OF METHYLATION BETWEEN GROUPS OF SAMPLES. THE APPLICATION OF GENE SET ANALYSIS TO IDENTIFY RELEVANT GROUPS OF GENES THAT ARE ENRICHED FOR DIFFERENTIALLY METHYLATED GENES IS OFTEN A MAJOR COMPONENT OF THE ANALYSIS OF THESE DATA. THIS CAN BE USED, FOR EXAMPLE, TO IDENTIFY PROCESSES OR PATHWAYS THAT ARE PERTURBED IN DISEASE DEVELOPMENT. WE SHOW THAT GENE-SET ANALYSIS, AS IT IS TYPICALLY APPLIED TO GENOME-WIDE METHYLATION ASSAYS, IS SEVERELY BIASED AS A RESULT OF DIFFERENCES IN THE NUMBERS OF CPG SITES ASSOCIATED WITH DIFFERENT CLASSES OF GENES AND GENE PROMOTERS. RESULTS: WE DEMONSTRATE THIS BIAS USING PUBLISHED DATA FROM A STUDY OF DIFFERENTIAL CPG ISLAND METHYLATION IN LUNG CANCER AND A DATASET WE GENERATED TO STUDY METHYLATION CHANGES IN PATIENTS WITH LONG-STANDING ULCERATIVE COLITIS. WE SHOW THAT SEVERAL OF THE GENE SETS THAT SEEM ENRICHED WOULD ALSO BE IDENTIFIED WITH RANDOMIZED DATA. WE SUGGEST TWO EXISTING APPROACHES THAT CAN BE ADAPTED TO CORRECT THE BIAS. ACCOUNTING FOR THE BIAS IN THE LUNG CANCER AND ULCERATIVE COLITIS DATASETS PROVIDES NOVEL BIOLOGICAL INSIGHTS INTO THE ROLE OF METHYLATION IN CANCER DEVELOPMENT AND CHRONIC INFLAMMATION, RESPECTIVELY. OUR RESULTS HAVE SIGNIFICANT IMPLICATIONS FOR MANY PREVIOUS GENOME-WIDE METHYLATION STUDIES THAT HAVE DRAWN CONCLUSIONS ON THE BASIS OF SUCH STRONGLY BIASED ANALYSIS. CONTACT: CATHAL.SEOIGHE@NUIGALWAY.IE SUPPLEMENTARY INFORMATION: SUPPLEMENTARY DATA ARE AVAILABLE AT BIOINFORMATICS ONLINE. 2013 17 1655 21 DOSE-DEPENDENCE, SEX- AND TISSUE-SPECIFICITY, AND PERSISTENCE OF RADIATION-INDUCED GENOMIC DNA METHYLATION CHANGES. RADIATION IS A WELL-KNOWN GENOTOXIC AGENT AND HUMAN CARCINOGEN THAT GIVES RISE TO A VARIETY OF LONG-TERM EFFECTS. ITS DETRIMENTAL INFLUENCE ON CELLULAR FUNCTION IS ACTIVELY STUDIED NOWADAYS. ONE OF THE MOST ANALYZED, YET LEAST UNDERSTOOD LONG-TERM EFFECTS OF IONIZING RADIATION IS TRANSGENERATIONAL GENOMIC INSTABILITY. THE INHERITANCE OF GENOMIC INSTABILITY SUGGESTS THE POSSIBLE INVOLVEMENT OF EPIGENETIC MECHANISMS, SUCH AS CHANGES OF THE METHYLATION OF CYTOSINE RESIDUES LOCATED WITHIN CPG DINUCLEOTIDES. IN THE CURRENT STUDY WE EVALUATED THE DOSE-DEPENDENCE OF THE RADIATION-INDUCED GLOBAL GENOME DNA METHYLATION CHANGES. WE ALSO ANALYZED THE EFFECTS OF ACUTE AND CHRONIC HIGH DOSE (5GY) EXPOSURE ON DNA METHYLATION IN LIVER, SPLEEN, AND LUNG TISSUES OF MALE AND FEMALE MICE AND EVALUATED THE POSSIBLE PERSISTENCE OF THE RADIATION-INDUCED DNA METHYLATION CHANGES. HERE WE REPORT THAT RADIATION-INDUCED DNA METHYLATION CHANGES WERE SEX- AND TISSUE-SPECIFIC, DOSE-DEPENDENT, AND PERSISTENT. IN PARALLEL WE HAVE STUDIED THE LEVELS OF DNA DAMAGE IN THE EXPOSED TISSUES. BASED ON THE CORRELATION BETWEEN THE LEVELS OF DNA METHYLATION AND DNA DAMAGE WE PROPOSE THAT RADIATION-INDUCED GLOBAL GENOME DNA HYPOMETHYLATION IS DNA REPAIR-RELATED. 2004 18 990 29 CHRONIC SOCIAL STRESS INDUCES DNA METHYLATION CHANGES AT AN EVOLUTIONARY CONSERVED INTERGENIC REGION IN CHROMOSOME X. CHRONIC STRESS RESULTING FROM PROLONGED EXPOSURE TO NEGATIVE LIFE EVENTS INCREASES THE RISK OF MOOD AND ANXIETY DISORDERS. ALTHOUGH CHRONIC STRESS CAN CHANGE GENE EXPRESSION RELEVANT FOR BEHAVIOR, MOLECULAR REGULATORS OF THIS CHANGE HAVE NOT BEEN FULLY DETERMINED. ONE PROCESS THAT COULD PLAY A ROLE IS DNA METHYLATION, AN EPIGENETIC PROCESS WHEREBY A METHYL GROUP IS ADDED ONTO NUCLEOTIDES, PREDOMINANTLY CYTOSINE IN THE CPG CONTEXT, AND WHICH CAN BE INDUCED BY CHRONIC STRESS. IT IS UNKNOWN TO WHAT EXTENT CHRONIC SOCIAL DEFEAT, A MODEL OF HUMAN SOCIAL STRESS, INFLUENCES DNA METHYLATION PATTERNS ACROSS THE GENOME. OUR STUDY ADDRESSED THIS QUESTION BY USING A TARGETED-CAPTURE APPROACH CALLED METHYL-SEQ TO INVESTIGATE DNA METHYLATION PATTERNS OF THE DENTATE GYRUS AT PUTATIVE REGULATORY REGIONS ACROSS THE MOUSE GENOME FROM MICE EXPOSED TO 14 DAYS OF SOCIAL DEFEAT. FINDINGS WERE REPLICATED IN INDEPENDENT COHORTS BY BISULFITE-PYROSEQUENCING. TWO DIFFERENTIALLY METHYLATED REGIONS (DMRS) WERE IDENTIFIED. ONE DMR WAS LOCATED AT INTRON 9 OF DROSHA, AND IT SHOWED REDUCED METHYLATION IN STRESSED MICE. THIS OBSERVATION REPLICATED IN ONE OF TWO INDEPENDENT COHORTS. A SECOND DMR WAS IDENTIFIED AT AN INTERGENIC REGION OF CHROMOSOME X, AND METHYLATION IN THIS REGION WAS INCREASED IN STRESSED MICE. THIS METHYLATION DIFFERENCE REPLICATED IN TWO INDEPENDENT COHORTS AND IN MAJOR DEPRESSIVE DISORDER (MDD) POSTMORTEM BRAINS. THESE RESULTS HIGHLIGHT A REGION NOT PREVIOUSLY KNOWN TO BE DIFFERENTIALLY METHYLATED BY CHRONIC SOCIAL DEFEAT STRESS AND WHICH MAY BE INVOLVED IN MDD. 2018 19 416 29 ANALYSIS OF THE DYNAMIC ABERRANT LANDSCAPE OF DNA METHYLATION AND GENE EXPRESSION DURING ARSENIC-INDUCED CELL TRANSFORMATION. INORGANIC ARSENIC IS A WELL-KNOWN CARCINOGEN ASSOCIATED WITH SEVERAL TYPES OF CANCER, BUT THE MECHANISMS INVOLVED IN ARSENIC-INDUCED CARCINOGENESIS ARE NOT FULLY UNDERSTOOD. RECENT EVIDENCE POINTS TO EPIGENETIC DYSREGULATION AS AN IMPORTANT MECHANISM IN THIS PROCESS; HOWEVER, THE EFFECTS OF EPIGENETIC ALTERATIONS IN GENE EXPRESSION HAVE NOT BEEN EXPLORED IN DEPTH. USING MICROARRAY DATA AND APPLYING A MULTIVARIATE CLUSTERING ANALYSIS IN A GAUSSIAN MIXTURE MODEL, WE DESCRIBE THE ALTERATIONS IN DNA METHYLATION AROUND THE PROMOTER REGION AND THE IMPACT ON GENE EXPRESSION IN HACAT CELLS DURING THE TRANSFORMATION PROCESS CAUSED BY CHRONIC EXPOSURE TO ARSENIC. USING THIS CLUSTERING APPROACH, THE GENES WERE GROUPED ACCORDING TO THEIR METHYLATION AND EXPRESSION STATUS IN THE EPIGENETIC LANDSCAPE, AND THE CHANGES THAT OCCURRED DURING THE CELLULAR TRANSFORMATION WERE IDENTIFIED ADEQUATELY. THUS, WE PRESENT A VALUABLE METHOD FOR IDENTIFYING EPIGENOMIC DYSREGULATION. 2019 20 2625 30 EPIGENOME-WIDE ASSOCIATION STUDY AND MULTI-TISSUE REPLICATION OF INDIVIDUALS WITH ALCOHOL USE DISORDER: EVIDENCE FOR ABNORMAL GLUCOCORTICOID SIGNALING PATHWAY GENE REGULATION. ALCOHOL USE DISORDER (AUD) IS A CHRONIC DEBILITATING DISORDER WITH LIMITED TREATMENT OPTIONS AND POORLY DEFINED PATHOPHYSIOLOGY. THERE ARE SUBSTANTIAL GENETIC AND EPIGENETIC COMPONENTS; HOWEVER, THE UNDERLYING MECHANISMS CONTRIBUTING TO AUD REMAIN LARGELY UNKNOWN. WE CONDUCTED THE LARGEST DNA METHYLATION EPIGENOME-WIDE ASSOCIATION STUDY (EWAS) ANALYSES CURRENTLY AVAILABLE FOR AUD (TOTAL N = 625) AND EMPLOYED A TOP HIT REPLICATION (N = 4798) USING A CROSS-TISSUE/CROSS-PHENOTYPIC APPROACH WITH THE GOAL OF IDENTIFYING NOVEL EPIGENETIC TARGETS RELEVANT TO AUD. RESULTS SHOW THAT A NETWORK OF DIFFERENTIALLY METHYLATED REGIONS IN GLUCOCORTICOID SIGNALING AND INFLAMMATION-RELATED GENES WERE ASSOCIATED WITH ALCOHOL USE BEHAVIORS. A TOP PROBE CONSISTENTLY ASSOCIATED ACROSS ALL COHORTS WAS LOCATED IN THE LONG NON-CODING RNA GROWTH ARREST SPECIFIC FIVE GENE (GAS5) (P < 10(-24)). GAS5 HAS BEEN IMPLICATED IN REGULATING TRANSCRIPTIONAL ACTIVITY OF THE GLUCOCORTICOID RECEPTOR AND HAS MULTIPLE FUNCTIONS RELATED TO APOPTOSIS, IMMUNE FUNCTION AND VARIOUS CANCERS. ENDOPHENOTYPIC ANALYSES USING PERIPHERAL CORTISOL LEVELS AND NEUROIMAGING PARADIGMS SHOWED THAT METHYLOMIC VARIATION IN GAS5 NETWORK-RELATED PROBES WERE ASSOCIATED WITH STRESS PHENOTYPES. POSTMORTEM BRAIN ANALYSES DOCUMENTED INCREASED GAS5 EXPRESSION IN THE AMYGDALA OF INDIVIDUALS WITH AUD. OUR DATA SUGGEST THAT ALCOHOL USE IS ASSOCIATED WITH DIFFERENTIAL METHYLATION IN THE GLUCOCORTICOID SYSTEM THAT MIGHT INFLUENCE STRESS AND INFLAMMATORY REACTIVITY AND SUBSEQUENTLY RISK FOR AUD. 2021