1 1325 113 DEPLETED URANIUM INDUCES SEX- AND TISSUE-SPECIFIC METHYLATION PATTERNS IN ADULT ZEBRAFISH. WE EXAMINED THE EFFECTS OF CHRONIC EXPOSURE TO DIFFERENT CONCENTRATIONS (2 AND 20 MUG L(-)(1)) OF ENVIRONMENTALLY RELEVANT WATERBORNE DEPLETED URANIUM (DU) ON THE DNA METHYLATION PATTERNS BOTH AT HPAII RESTRICTION SITES (5'-CCGG-3') AND ACROSS THE WHOLE GENOME IN THE ZEBRAFISH BRAIN, GONADS, AND EYES. WE FIRST IDENTIFIED SEX-DEPENDENT DIFFERENCES IN THE METHYLATION LEVEL OF HPAII SITES AFTER EXPOSURE. IN MALES, THESE EFFECTS WERE PRESENT AS EARLY AS 7 DAYS AFTER EXPOSURE TO 20 MUG L(-)(1) DU, AND WERE EVEN MORE PRONOUNCED IN THE BRAIN, GONADS, AND EYES AFTER 24 DAYS. HOWEVER, IN FEMALES, HYPOMETHYLATION WAS ONLY OBSERVED IN THE GONADS AFTER EXPOSURE TO 20 MUG L(-)(1) DU FOR 24 DAYS. SEX-SPECIFIC EFFECTS OF DU WERE ALSO APPARENT AT THE WHOLE-GENOME LEVEL, BECAUSE IN MALES, EXPOSURE TO 20 MUG L(-)(1) DU FOR 24 DAYS RESULTED IN CYTOSINE HYPERMETHYLATION IN THE BRAIN AND EYES AND HYPOMETHYLATION IN THE GONADS. IN CONTRAST, IN FEMALES, HYPERMETHYLATION WAS OBSERVED IN THE BRAIN AFTER EXPOSURE TO BOTH CONCENTRATIONS OF DU FOR 7 DAYS. BASED ON OUR CURRENT KNOWLEDGE OF URANIUM TOXICITY, SEVERAL HYPOTHESES ARE PROPOSED TO EXPLAIN THESE FINDINGS, INCLUDING THE INVOLVEMENT OF OXIDATIVE STRESS, ALTERATION OF DEMETHYLATION ENZYMES AND THE CALCIUM SIGNALING PATHWAY. THIS STUDY REPORTS, FOR THE FIRST TIME, THE SEX- AND TISSUE-SPECIFIC EPIGENETIC CHANGES THAT OCCUR IN A NONHUMAN ORGANISM AFTER EXPOSURE TO ENVIRONMENTALLY RELEVANT CONCENTRATIONS OF URANIUM, WHICH COULD INDUCE TRANSGENERATIONAL EPIGENETIC EFFECTS. 2016 2 1531 20 DNA METHYLATION DURING DEPLETED URANIUM-INDUCED LEUKEMIA. OBJECTIVES: THE RADIOACTIVE HEAVY METAL DEPLETED URANIUM (DU) IS USED IN KINETIC-ENERGY PENETRATORS IN MILITARY APPLICATIONS. THE OBJECTIVE OF THIS STUDY WAS TO DETERMINE INVOLVEMENT OF DNA METHYLATION IN DU-INDUCED LEUKEMIA. METHODS: METHYLATION WAS MEASURED BY DIRECT ANALYSIS OF 5-METHYLCYTOSINE CONTENT OF SPLEEN DNA IN DU LEUKEMIC MICE. RESULTS: SPLEEN HYPOMETHYLATION OCCURRED DURING DU-INDUCED LEUKEMOGENESIS (CHRONIC INTERNAL DU EXPOSURE). ABERRANT GENE TRANSCRIPTION WAS ALSO DETECTED. CONCLUSIONS: EPIGENETIC MECHANISMS ARE IMPLICATED IN DU-INDUCED LEUKEMIA. THESE DATA ARE EVIDENCE OF ABERRANT DNA HYPOMETHYLATION BEING ASSOCIATED WITH DU LEUKEMOGENESIS. 2009 3 4008 31 LOW DOSE OF URANIUM INDUCES MULTIGENERATIONAL EPIGENETIC EFFECTS IN RAT KIDNEY. PURPOSE: A PROTOCOL OF CHRONIC EXPOSURE TO LOW DOSE OF URANIUM WAS ESTABLISHED IN ORDER TO DISTINGUISH THE SEXUAL DIFFERENCES AND THE DEVELOPMENTAL PROCESS THAT ARE CRITICAL WINDOWS FOR EPIGENETIC EFFECTS OVER GENERATIONS. METHODS: BOTH MALE AND FEMALE RATS WERE CONTAMINATED THROUGH THEIR DRINKING WATER WITH A NON-TOXIC SOLUTION OF URANYL NITRATE FOR 9 MONTHS. THE EXPOSED GENERATION (F0) AND THE FOLLOWING TWO GENERATIONS (F1 AND F2) WERE EXAMINED. CLINICAL MONITORING, GLOBAL DNA METHYLATION PROFILE AND DNA METHYLTRANSFERASES (DNMTS) GENE EXPRESSION WERE ANALYZED IN KIDNEYS. RESULTS: WHILE THE BODY WEIGHT OF F1 MALES INCREASED, A SMALL DECREASE IN KIDNEY AND BODY WEIGHT WAS OBSERVED IN F2 MALES. IN ADDITION, GLOBAL DNA HYPERMETHYLATION PROFILE IN KIDNEY CELLS WAS OBSERVED IN F1 AND F2 MALES. QPCR RESULTS REVEAL A SIGNIFICANT INCREASE OF METHYLTRANSFERASE GENES EXPRESSION (DNMT1 AND DNMT3A) FOR F2 FEMALES. CONCLUSIONS: IN THE FIELD OF PUBLIC HEALTH POLICY AND TO RAISE ATTENTION TO GENERATIONAL EFFECTS FOR THE RISK ASSESSMENT OF THE ENVIRONMENTAL EXPOSURES, LOW DOSES OF URANIUM DO NOT IMPLY CLINICAL EFFECTS ON ADULT EXPOSED RATS. HOWEVER, OUR RESULTS CONFIRM THE IMPORTANCE OF THE DEVELOPMENTAL WINDOWS' SENSITIVITY IN ADDITION TO THE SEXUAL DIMORPHISMS OF THE OFFSPRING. 2018 4 1511 41 DNA METHYLATION AND POTENTIAL MULTIGENERATIONAL EPIGENETIC EFFECTS LINKED TO URANIUM CHRONIC LOW-DOSE EXPOSURE IN GONADS OF MALES AND FEMALES RATS. INTRODUCTION: AN INCREASED HEALTH PROBLEM IN INDUSTRIALISED COUNTRIES IS THE CONTEMPORARY CONCERN OF PUBLIC AND SCIENTIFIC COMMUNITY AS WELL. THIS HAS BEEN ATTRIBUTED IN PART TO ACCUMULATED ENVIRONMENTAL POLLUTANTS ESPECIALLY RADIOACTIVE SUBSTANCES AND THE USE OF NUCLEAR POWER PLANTS WORLDWIDE. HOWEVER, THE OUTCOME OF CHRONIC EXPOSURE TO LOW DOSES OF A RADIONUCLIDE SUCH AS URANIUM REMAINS UNKNOWN. RECENTLY, A PARADIGM SHIFT IN THE PERCEPTION OF RISK OF RADIOTOXICOLOGY HAS EMERGED THROUGH INVESTIGATING THE POSSIBILITY OF TRANSMISSION OF BIOLOGICAL EFFECTS OVER GENERATIONS, IN PARTICULAR BY EPIGENETIC PATHWAYS. THESE PROCESSES ARE KNOWN FOR THEIR CRUCIAL ROLES ASSOCIATED WITH THE DEVELOPMENT OF SEVERAL DISEASES. OBJECTIVE: THE CURRENT WORK INVESTIGATES THE EPIGENETIC EFFECT OF CHRONIC EXPOSURE TO LOW DOSES OF URANIUM AND ITS INHERITANCE ACROSS GENERATIONS. MATERIALS AND METHODS TO TEST THIS PROPOSITION, A RODENT MULTIGENERATIONAL MODEL, MALES AND FEMALES, WERE EXPOSED TO A NON-TOXIC CONCENTRATION OF URANIUM (40MGL(-1) DRINKING WATER) FOR NINE MONTHS. THE URANIUM EFFECTS ON WERE EVALUATED OVER THREE GENERATIONS (F0, F1 AND F2) BY ANALYSING THE DNA METHYLATION PROFILE AND DNMT GENES EXPRESSION IN OVARIES AND TESTES TISSUES. RESULTS: HERE WE REPORT A SIGNIFICANT HYPERMETHYLATION OF TESTES DNA (P <0.005) WHEREAS OVARIES SHOWED HYPOMETHYLATED DNA (P <0.005). INTERESTINGLY, THIS DNA METHYLATION PROFILE WAS SIGNIFICANTLY MAINTAINED ACROSS GENERATIONS F0, F1 AND F2. FURTHERMORE, QPCR RESULTS OF BOTH TISSUES IMPLY A SIGNIFICANT CHANGE IN THE EXPRESSION OF DNA METHYLTRANSFERASE GENES (DNMT 1 AND DNMT3A/B) AS WELL. CONCLUSION: ALTOGETHER, OUR WORK DEMONSTRATES FOR THE FIRST TIME A SEX-DEPENDANCE AND INHERITANCE OF EPIGENETIC MARKS, DNA METHYLATION, AS A BIOLOGICAL RESPONSE TO THE EXPOSURE TO LOW DOSES OF URANIUM. HOWEVER, IT IS NOT CLEAR WHICH TYPE OF REPRODUCTIVE CELL TYPE IS MORE RESPONSIVE IN THIS CONTEXT. 2018 5 836 28 CHEMICAL TOXICITY AND RADIOACTIVITY OF DEPLETED URANIUM: THE EVIDENCE FROM IN VIVO AND IN VITRO STUDIES. THE MAIN AIM OF THIS REVIEW IS TO SUMMARIZE AND DISCUSS THE CURRENT STATE OF KNOWLEDGE ON CHEMICAL TOXICITY AND RADIOACTIVITY OF DEPLETED URANIUM (DU) AND THEIR EFFECT ON LIVING SYSTEMS AND CELL LINES. THIS WAS DONE BY PRESENTING A SUMMARY OF PREVIOUS INVESTIGATIONS CONDUCTED ON DIFFERENT MAMMALIAN BODY SYSTEMS AND CELL CULTURES IN TERMS OF POTENTIAL CHANGES CAUSED BY EITHER CHEMICAL TOXICITY OR RADIOACTIVITY OF DU. IN ADDITION, THE AUTHORS AIMED TO POINT OUT THE LIMITATIONS OF THOSE STUDIES AND POSSIBLE FUTURE DIRECTIONS. THE MAJORITY OF BOTH IN VITRO AND IN VIVO STUDIES PERFORMED USING ANIMAL MODELS REGARDING POSSIBLE EFFECTS CAUSED BY ACUTE OR CHRONIC DU EXPOSURE HAS BEEN REVIEWED. FURTHERMORE, EXPOSURE TIME AND DOSE, DU PARTICLE SOLUBILITY, AND URANIUM ISOTOPES AS FACTORS AFFECTING THE EXTENT OF DU EFFECTS HAVE BEEN DISCUSSED. SPECIAL ATTENTION HAS BEEN DEDICATED TO CHROMOSOMAL ABERRATIONS, DNA DAMAGE AND DNA BREAKS, AS WELL AS MICRONUCLEI FORMATION AND EPIGENETIC CHANGES, AS DU HAS RECENTLY BEEN CONSIDERED A POSSIBLE CAUSATIVE FACTOR OF ALL THESE PROCESSES. THEREFORE, THIS APPROACH MIGHT REPRESENT A NOVEL AREA OF STUDY OF DU-RELATED IRRADIATION EFFECTS ON HEALTH. SINCE DIFFERENT STUDIES OFFER CONTRADICTORY RESULTS, THE MAIN AIM OF THIS REVIEW IS TO SUMMARIZE AND BRIEFLY DISCUSS PREVIOUSLY OBTAINED RESULTS IN ORDER TO IDENTIFY THE CURRENT OPINION ON DU TOXICITY AND RADIOACTIVITY EFFECTS IN RELATION TO EXPOSURE TYPE AND DURATION, AS WELL AS DU PROPERTIES. 2017 6 457 28 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 7 985 19 CHRONIC RADIATION EXPOSURE AS AN ECOLOGICAL FACTOR: HYPERMETHYLATION AND GENETIC DIFFERENTIATION IN IRRADIATED SCOTS PINE POPULATIONS. GENETIC AND EPIGENETIC CHANGES WERE INVESTIGATED IN CHRONICALLY IRRADIATED SCOTS PINE (PINUS SYLVESTRIS L.) POPULATIONS FROM TERRITORIES THAT WERE HEAVILY CONTAMINATED BY RADIONUCLIDES AS RESULT OF THE CHERNOBYL NUCLEAR POWER PLANT ACCIDENT. IN COMPARISON TO THE REFERENCE SITE, THE GENETIC DIVERSITY REVEALED BY ELECTROPHORETIC MOBILITY OF AFLPS WAS FOUND TO BE SIGNIFICANTLY HIGHER AT THE RADIOACTIVELY CONTAMINATED AREAS. IN ADDITION, THE GENOME OF PINE TREES WAS SIGNIFICANTLY HYPERMETHYLATED AT 4 OF THE 7 AFFECTED SITES. 2018 8 2698 35 EXAMINING MULTI- AND TRANSGENERATIONAL BEHAVIORAL AND MOLECULAR ALTERATIONS RESULTING FROM PARENTAL EXPOSURE TO AN ENVIRONMENTAL PCB AND PBDE MIXTURE. POLYCHLORINATED BIPHENYLS (PCBS) AND POLYBROMINATED DIPHENYL ETHERS (PBDES) ARE PERSISTENT ORGANIC POLLUTANTS EXTENSIVELY USED DURING THE 20(TH) CENTURY AND STILL PRESENT IN AQUATIC ENVIRONMENTS DESPITE THEIR BAN. EFFECTS OF EXPOSURE TO THESE COMPOUNDS OVER GENERATIONS ARE POORLY DOCUMENTED. THEREFORE, OUR AIMS WERE TO CHARACTERIZE BEHAVIORAL RESPONSES AND UNDERLYING MOLECULAR MECHANISMS IN ZEBRAFISH EXPOSED TO AN ENVIRONMENTALLY RELEVANT MIXTURE OF PCBS AND PBDES AS WELL AS IN FOUR UNEXPOSED OFFSPRING GENERATIONS. ZEBRAFISH (F0) WERE CHRONICALLY EXPOSED FROM THE FIRST MEAL ONWARD TO A DIET SPIKED WITH A MIXTURE CONTAINING 22 PCB AND 7 PBDE CONGENERS IN PROPORTIONS AND CONCENTRATIONS REFLECTING ENVIRONMENTAL SITUATIONS (SIGMAPCBS = 1991 AND SIGMAPBDES = 411 NG/G). FOUR OFFSPRING GENERATIONS (F1 TO F4) WERE OBTAINED FROM THIS F0 AND WERE NOT FURTHER EXPOSED. BEHAVIOR WAS ASSESSED AT BOTH LARVAL AND ADULT STAGES. MECHANISMS RELATED TO BEHAVIORAL DEFECTS (HABENULA MATURATION AND C-FOS TRANSCRIPTION) AND METHYLATION (DNMTS TRANSCRIPTION) WERE MONITORED IN LARVAE. EXPOSED ADULT F0 AS WELL AS F1 AND F3 ADULTS DISPLAYED NO BEHAVIORAL CHANGE WHILE F2 EXPRESSED ANXIETY-LIKE BEHAVIOR. LARVAL BEHAVIOR WAS ALSO DISRUPTED, I.E. HYPERACTIVE AFTER LIGHT TO DARK TRANSITION IN F1 OR HYPOACTIVE IN F2, F3 AND F4. BEHAVIORAL DISRUPTIONS MAY BE RELATED TO DEFECT IN HABENULA MATURATION (OBSERVED IN F1) AND CHANGE IN C-FOS TRANSCRIPTION (OBSERVED IN F1 AND F2). TRANSCRIPTION OF THE GENE ENCODING DNA METHYLTRANSFERASE (DNMT3BA) WAS ALSO MODIFIED IN ALL GENERATIONS. OUR RESULTS LEAD US TO HYPOTHESIZE THAT CHRONIC DIETARY EXPOSURE TO AN ENVIRONMENTALLY RELEVANT MIXTURE OF PCB AND PBDE TRIGGERS MULTIGENERATIONAL AND TRANSGENERATIONAL MOLECULAR AND BEHAVIORAL DISRUPTIONS IN A VERTEBRATE MODEL. 2019 9 4923 26 PARENTAL DIURON EXPOSURE CAUSES LOWER HATCHABILITY AND ABNORMAL OVARIAN DEVELOPMENT IN OFFSPRING OF MEDAKA (ORYZIAS MELASTIGMA). DIURON IS ONE OF THE MOST WIDELY USED HERBICIDES WORLDWIDE. IT HAS BEEN WIDELY DETECTED IN VARIOUS AQUATIC ENVIRONMENTS, ESPECIALLY IN MARINE ECOSYSTEMS. ALTHOUGH DIRECT EFFECTS OF DIURON EXPOSURE ON VARIOUS ORGANISMS HAVE BEEN REPORTED, LITTLE IS KNOWN ABOUT ITS EFFECTS ON MARINE FISHES INCLUDING MULTIGENERATIONAL EFFECTS. HEREIN, THE FILIAL GENERATION (F1) OF DIURON-EXPOSED MARINE MEDAKA (ORYZIAS MELASTIGMA) (F0) WAS RAISED IN CLEAN SEAWATER FROM FERTILIZED EGGS TO ADULTHOOD AND USED AS A MARINE FISH MODEL TO STUDY THE POTENTIAL MULTIGENERATIONAL EFFECTS OF DIURON. WE FOUND THAT THE SUCCESSFUL HATCHING OF F1 LARVAE WAS SIGNIFICANTLY REDUCED AND THAT OVARIAN DEVELOPMENT IN F1 FEMALES WAS RETARDED. A SIGNIFICANT INCREASE IN THE PERCENTAGE OF PREVITELLOGENIC OOCYTES, ALONG WITH A VISUAL DECREASE IN THE PERCENTAGE OF VITELLOGENIC AND MATURE OOCYTES IN THE F1 OVARY, WERE OBSERVED. THE HORMONE LEVELS OF THE HYPOTHALAMUS-PITUITARY-GONAD-LIVER AXIS AND VITELLOGENIN-RELATED TRANSCRIPTION WERE DOWNREGULATED. IN ADDITION, THE MRNA LEVELS OF DNA METHYLTRANSFERASE IN THE BRAIN, OVARY AND LIVER OF F1 ADULT FISH EXHIBITED SIGNIFICANT UPREGULATION, SUGGESTING THAT THE PROBABLE UNDERLYING MULTIGENERATIONAL MECHANISM MIGHT BE ASSOCIATED WITH EPIGENETIC MODIFICATIONS. TAKEN TOGETHER, THESE RESULTS DEMONSTRATED THAT CHRONIC ENVIRONMENTAL DIURON EXPOSURE IN F0 MARINE MEDAKA CAN INHIBIT F1 OVARY DEVELOPMENT AND SUGGESTED THAT DIURON MAY AFFECT MARINE FISH THRIVING IN THE OCEAN. 2022 10 6552 31 TRANSGENERATIONAL DNA METHYLATION CHANGES IN DAPHNIA MAGNA EXPOSED TO CHRONIC GAMMA IRRADIATION. OUR AIM WAS TO INVESTIGATE EPIGENETIC CHANGES IN DAPHNIA MAGNA AFTER A 25-DAY CHRONIC EXTERNAL GAMMA IRRADIATION (GENERATION F0 EXPOSED TO 6.5 MUGY.H(-1) OR 41.3 MGY.H(-1)) AND THEIR POTENTIAL INHERITANCE BY SUBSEQUENT RECOVERING GENERATIONS, NAMELY, F2 (EXPOSED AS GERMLINE CELLS IN F1 EMBRYOS) AND F3 (THE FIRST TRULY UNEXPOSED GENERATION). EFFECTS ON SURVIVAL, GROWTH, AND REPRODUCTION WERE OBSERVED AND DNA WAS EXTRACTED FOR WHOLE-GENOME BISULFITE SEQUENCING IN ALL GENERATIONS. RESULTS SHOWED EFFECTS ON REPRODUCTION IN F0 BUT NO EFFECT IN THE SUBSEQUENT GENERATIONS F1, F2, AND F3. IN CONTRAST, WE OBSERVED SIGNIFICANT METHYLATION CHANGES AT SPECIFIC CPG POSITIONS IN EVERY GENERATION INDEPENDENT OF DOSE RATE, WITH A MAJORITY OF HYPOMETHYLATION. SOME OF THESE CHANGES WERE SHARED BETWEEN DOSE RATES AND BETWEEN GENERATIONS. ASSOCIATED GENE FUNCTIONS INCLUDED GENE FAMILIES AND GENES THAT WERE PREVIOUSLY SHOWN TO PLAY ROLES DURING EXPOSURE TO IONIZING RADIATION. COMMON METHYLATION CHANGES DETECTED BETWEEN GENERATIONS F2 AND F3 CLEARLY SHOWED THAT EPIGENETIC MODIFICATIONS CAN BE TRANSMITTED TO UNEXPOSED GENERATIONS, MOST LIKELY THROUGH THE GERMLINE, WITH POTENTIAL IMPLICATIONS FOR ENVIRONMENTAL RISK. 2018 11 1816 25 EFFECTS OF CHRONIC EXPOSURE TO BENZOPHENONE AND DICLOFENAC ON DNA METHYLATION LEVELS AND REPRODUCTIVE SUCCESS IN A MARINE COPEPOD. THE UV-FILTER BENZOPHENONE AND THE ANTI-INFLAMMATORY DICLOFENAC ARE COMMONLY DETECTED IN THE ENVIRONMENT. THE AIM OF THIS STUDY WAS TO ASSESS THE MULTIGENERATIONAL EFFECTS OF CHRONIC EXPOSURE TO LOW CONCENTRATIONS OF THESE CHEMICALS ON TOXICITY AND DNA METHYLATION LEVELS IN THE COPEPOD GLADIOFERENS PECTINATUS. ACUTE TOXICITY TESTS WERE CONDUCTED TO DETERMINE THE SENSITIVITY OF G. PECTINATUS TO THE CHEMICALS. ALL CHEMICALS IMPACTED BREEDING, HATCHING AND EGG VIABILITY. DICLOFENAC (1 MG.L(-1)) REDUCED THE NUMBER OF EGGS PER GRAVID FEMALE. BENZOPHENONE (0.5 MG.L(-1)) DECREASED EGG HATCHING SUCCESS. EXPOSURE TO THE REFERENCE TOXICANT COPPER (0.02 MG.L(-1)) LED TO UNSUCCESSFUL HATCHING. EFFECTS ON DNA METHYLATION WAS ESTIMATED BY THE PERCENTAGE OF 5- METHYLCYTOSINE. THE TREATMENTS RESULTED IN STRONG DIFFERENCES IN DNA METHYLATION WITH INCREASED METHYLATION IN THE EXPOSED ANIMALS. THE TWO CHEMICALS IMPACTED BOTH EGG VIABILITY AND THE INDUCTION OF DIFFERENTIAL DNA METHYLATION, SUGGESTING POTENTIAL INTRA- AND TRANS-GENERATIONAL EVOLUTIONARY EFFECTS. 2018 12 6553 29 TRANSGENERATIONAL EFFECTS IN DNA METHYLATION, GENOTOXICITY AND REPRODUCTIVE PHENOTYPE BY CHRONIC ARSENIC EXPOSURE. AN EMERGING CONCERN IS THE INFLUENCES OF EARLY LIFE EXPOSURE TO ENVIRONMENTAL TOXICANTS ON OFFSPRING CHARACTERISTICS IN LATER LIFE. SINCE RECENT EVIDENCE SUGGESTS A TRANSGENERATIONAL TRANSFERENCE OF ABERRANT PHENOTYPES FROM EXPOSED-PARENTS TO NON-EXPOSED OFFSPRING RELATED TO ADULT-ONSET DISEASES INCLUDING REPRODUCTIVE PHENOTYPE. THE TRANSGENERATIONAL POTENTIAL OF ARSENIC A WELL KNOW GENOTOXIC AND EPIGENETIC MODIFIER AGENT HAS NOT BEEN ASSESSED IN MAMMALS UNTIL NOW. IN THIS EXPERIMENTAL STUDY, WE EVALUATED THE TRANSGENERATIONAL EFFECTS OF ARSENIC IN A RAT MODEL WITH CHRONIC EXPOSURE TO ARSENIC. RATS CHRONICALLY EXPOSED TO ARSENIC IN DRINKING WATER (1 MG AS(2)O(3)/ML) (F0) WERE MATED TO PRODUCE THE ARSENIC LINEAGE (F1, F2, AND F3). THE ARSENIC TOXIC EFFECTS ON WERE EVALUATED OVER THE FOUR GENERATIONS BY ANALYZING THE DNA METHYLATION PERCENTAGE, GENOTOXICITY IN WBC AND PHYSICAL AND REPRODUCTIVE PARAMETERS, INCLUDING SPERM QUALITY PARAMETERS AND HISTOPATHOLOGICAL EVALUATION OF THE GONADS. CHRONIC EXPOSURE TO ARSENIC CAUSED GENOTOXIC DAMAGE (F0-F3) DIFFERENT METHYLATION PATTERNS, ALTERATIONS IN PHYSICAL AND REPRODUCTIVE PARAMETERS, ABERRANT MORPHOLOGY IN THE OVARIES (F0 AND F1) AND TESTICLES (F1-F3), AND A DECREASE IN THE QUALITY OF SPERM (F0-F3, EXCEPT F2). PARENTAL CHRONIC ARSENIC EXPOSURE CAUSES TRANSGENERATIONAL GENOTOXICITY AND CHANGES IN GLOBAL DNA METHYLATION WHICH MIGHT BE ASSOCIATED WITH REPRODUCTIVE DEFECTS IN RATS. COMBINED WITH RECENT STUDIES REVEAL THAT DISTURBANCES IN THE EARLY LIFE OF AN INDIVIDUAL CAN AFFECT THE HEALTH OF LATER GENERATIONS. 2021 13 3109 37 GENOTOXIC AND EPIGENETIC EFFECTS OF DIURON IN THE PACIFIC OYSTER: IN VITRO EVIDENCE OF INTERACTION BETWEEN DNA DAMAGE AND DNA METHYLATION. RECENTLY, RESEARCH HAS CONTRIBUTED TO BETTER KNOWLEDGE ON THE OCCURRENCE OF PESTICIDES IN COASTAL WATER BY IDENTIFYING FREQUENTLY DETECTED SUBSTANCES, THEIR CONCENTRATION RANGE AND THEIR ACUTE AND CHRONIC TOXICITY FOR ORGANISMS. PESTICIDE POLLUTION IS OF PARTICULAR CONCERN IN FRANCE DUE TO IMPORTANT AGRICULTURAL ACTIVITIES AND PRESENCE OF SEVERAL EXOREIC CATCHMENT AREAS THAT VEHICLE PESTICIDES UP TO COASTAL WATERS, IMPACTING NON-TARGET MARINE SPECIES. SEVERAL ECOTOXICOLOGY QUESTIONS REMAIN TO BE ADDRESSED CONCERNING THE LONG-TERM EFFECTS OF CHRONIC PESTICIDE EXPOSURE AND THE MECHANISMS INVOLVED IN ADAPTATION TO CHEMICAL STRESS. IN THE PRESENT STUDY, WE BROUGHT NEW INSIGHTS ON THE GENETIC AND EPIGENETIC EFFECTS OF THE HERBICIDE DIURON IN OYSTER GENITORS. DURING GAMETOGENESIS, WE EXPOSED CRASSOSTREA GIGAS TO ENVIRONMENTALLY REALISTIC HERBICIDE CONCENTRATIONS (0.2-0.3 MUG L(-1) DURING TWO 7-DAY PERIODS AT HALF-COURSE AND END OF GAMETOGENESIS). DIURON EXPOSURE WAS SHOWN TO DECREASE GLOBAL DNA METHYLATION AND TOTAL METHYLTRANSFERASE ACTIVITY IN WHOLE OYSTER TISSUE; THIS IS CONSISTENT WITH THE PREVIOUS OBSERVATION OF A SIGNIFICANT DECREASE IN DNMT1 GENE EXPRESSION. DIURON EFFECT SEEMED TO BE TISSUE-SPECIFIC; HYPERMETHYLATION WAS DETECTED IN THE DIGESTIVE GLAND, WHEREAS DIURON EXPOSURE HAD NO EFFECT ON GILL AND GONAD TISSUE. THE GENOTOXICITY OF DIURON WAS CONFIRMED BY THE DETECTION OF ONE ADDUCT IN GONAD DNA. BY USING IN VITRO APPROACHES AND HUMAN DNMT1 (DNMT1 HAS NOT BEEN PURIFIED YET IN BIVALVES), THE PRESENCE OF DNA LESIONS (ADDUCT, 8-OXODGUO) WAS SHOWN TO INTERFERE WITH DNMT1 ACTIVITY, INDICATING A COMPLEX INTERACTION BETWEEN DNA DAMAGE AND DNA METHYLATION. BASED ON OUR RESULTS, WE PROPOSE MECHANISMS TO EXPLAIN THE EFFECT OF DIURON EXPOSURE ON DNA METHYLATION, A WIDESPREAD EPIGENETIC MARK. 2021 14 73 33 A MULTI-GENERATIONAL STUDY ON LOW-DOSE BPA EXPOSURE IN WISTAR RATS: EFFECTS ON MATERNAL BEHAVIOR, FLAVOR INTAKE AND DEVELOPMENT. BISPHENOL A (BPA) IS A COMMON ENDOCRINE DISRUPTOR FOUND AS AN ENVIRONMENTAL AND FOOD CONTAMINANT. IT EXERTS BOTH DEVELOPMENTAL AND BEHAVIORAL EFFECTS, MAINLY WHEN EXPOSURE OCCURS IN EARLY LIFE. THE AIM OF THIS STUDY WAS TO DETERMINE THE MULTI-GENERATIONAL EFFECTS OF CHRONIC, HUMAN-RELEVANT LOW-DOSE EXPOSURE TO BPA ON DEVELOPMENT, MATERNAL BEHAVIOR AND FLAVOR PREFERENCE IN WISTAR RATS. BPA WAS ORALLY ADMINISTERED AT A DAILY DOSE OF 5 MUG/KG BODY WEIGHT TO F0 PREGNANT DAMS FROM THE FIRST DAY OF GESTATION (GD 1) UNTIL THE LAST DAY OF LACTATION (LD 21), AND THEN TO F1 OFFSPRING FROM WEANING (PND 21) TO ADULTHOOD (PND 100). F2 OFFSPRING WERE NOT EXPOSED. DEVELOPMENT AND CLINICAL SIGNS OF TOXICITY WERE ASSESSED DAILY. MATERNAL BEHAVIOR WAS EVALUATED BY OBSERVING NURSING AND PUP-CARING ACTIONS, AS WELL AS "NON-MATERNAL" BEHAVIORS IN F0 AND F1 DAMS FROM PARTURITION UNTIL LD 8. THE FLAVOR PREFERENCES OF F1 AND F2 OFFSPRING WERE EVALUATED BASED ON THE INTAKE OF SWEET, SALT AND FAT SOLUTIONS USING THE TWO-BOTTLE CHOICE TEST ON PND 21-34 AND PND 86-99. BPA EXPOSURE: 1) DECREASED MATERNAL BEHAVIOR IN F1 DAMS, 2) CAUSED DEVELOPMENTAL DEFECTS IN BOTH F1 AND F2 OFFSPRING, WITH A NOTICEABLE DECREASE IN ANOGENITAL DISTANCE IN MALE RATS, AND 3) DID NOT AFFECT FLAVORED SOLUTION INTAKE IN F1, BUT INDUCED CHANGES IN SWEET PREFERENCE IN F2 JUVENILES AND IN SALT AND FAT SOLUTION INTAKES IN F2 ADULTS, AND 4) INDUCED A BODY WEIGHT INCREASE IN THE F2 GENERATION ONLY, WHEREAS FOOD INTAKE AND WATER CONSUMPTION DID NOT CHANGE. TAKEN AS A WHOLE, OUR FINDINGS SHOWED THAT BOTH GESTATIONAL (F0) AND LIFELONG (F1) EXPOSURES TO A HUMAN-RELEVANT DOSE OF BPA COULD INDUCE MULTI-GENERATIONAL EFFECTS ON BOTH DEVELOPMENT AND BEHAVIOR. THESE RESULTS SUGGEST POSSIBLE SELECTIVE NEUROENDOCRINE DEFECTS AND/OR EPIGENETIC CHANGES CAUSED BY BPA EXPOSURE. 2014 15 1115 34 COMPARATIVE ANALYSIS OF EPIGENETIC VARIABILITY IN TWO PINE SPECIES EXPOSED TO CHRONIC RADIATION IN THE CHERNOBYL AND FUKUSHIMA AFFECTED ZONES. COMPARATIVE ANALYSIS OF EPIGENETIC VARIABILITY IN TWO PINE SPECIES AFFECTED AS A RESULT OF THE CHERNOBYL AND FUKUSHIMA ACCIDENTS IS PRESENTED. THE ABSORBED DOSE RATE WITHIN THE AFFECTED CHERNOBYL SITES VARIES OVER A WIDER RANGE (1.5-24.6 MUGY/H) THAN WITHIN THE FUKUSHIMA SITES (3.5-6.5 MUGY/H). IT WAS SHOWN THAT CHRONIC IRRADIATION CAN CHANGE THE LEVEL OF WHOLE GENOME METHYLATION IN PINE POPULATIONS, BUT IN DIFFERENT WAYS. THE GENOMES OF JAPANESE RED PINES ARE HYPOMETHYLATED, AND THE DEGREE OF METHYLATION AND HYDROXYMETHYLATION DECREASES WITH AN INCREASE IN THE LEVEL OF RADIATION EXPOSURE. IN CONTRAST, THE PERCENTAGES OF GENOME METHYLATION AND HYDROXYMETHYLATION IN SCOTS PINE POPULATIONS EXCEED THE REFERENCE LEVELS. THE OBSERVED DISCREPANCY IN THE PATTERNS OF GENOME-WIDE DNA METHYLATION CAN BE ATTRIBUTED PARTLY TO THE DESIGN OF THE STUDY (DIFFERENCES IN THE CLIMATE, RADIATION DOSE, AGE AND SPECIES OF THE PINES) WHICH COULD AFFECT THE RESULTS. IN THE FRAME OF IRAP ANALYSIS, A LARGER NUMBER OF DIFFERENT BANDS WAS OBSERVED IN THE CHERNOBYL POPULATIONS COMPARED TO THE JAPANESE POPULATIONS. BOTH THE JAPANESE AND CHERNOBYL POPULATIONS ARE CHARACTERIZED BY SIGNIFICANT GENETIC VARIABILITY. HOWEVER, THE MAIN PART OF THIS VARIABILITY IS OBSERVED WITHIN POPULATIONS. THE DENDROGRAMS, BASED ON PRESENCE/ABSENCE OF IRAP FRAGMENTS AND NEI'S GENETIC DISTANCES, REVEALED SUBDIVISIONS OF THE CHERNOBYL AND JAPANESE POPULATIONS ACCORDING TO THE LEVEL OF RADIOACTIVE CONTAMINATION. ANALYSIS OF THE RESULTS PRESENTED WILL IMPROVE OUR UNDERSTANDING OF THE MECHANISMS UNDERLYING THE RESPONSES OF PINE TREES TO CHRONIC RADIATION EXPOSURE. 2023 16 184 31 ACCOUNTING FOR TRANSGENERATIONAL EFFECTS OF TOXICANT EXPOSURE IN POPULATION MODELS ALTERS THE PREDICTED LONG-TERM POPULATION STATUS. ACUTE ENVIRONMENTAL STRESSORS SUCH AS SHORT-TERM EXPOSURE TO POLLUTANTS CAN HAVE LASTING EFFECTS ON ORGANISMS, POTENTIALLY IMPACTING FUTURE GENERATIONS. PARENTAL EXPOSURE TO TOXICANTS CAN RESULT IN CHANGES TO THE EPIGENOME (E.G., DNA METHYLATION) THAT ARE PASSED DOWN TO SUBSEQUENT, UNEXPOSED GENERATIONS. HOWEVER, IT IS DIFFICULT TO GAUGE THE CUMULATIVE POPULATION-SCALE IMPACTS OF EPIGENETIC EFFECTS FROM LABORATORY EXPERIMENTS ALONE. HERE, WE DEVELOPED A SIZE- AND AGE-STRUCTURED DELAY-COORDINATE POPULATION MODEL TO EVALUATE THE LONG-TERM CONSEQUENCES OF EPIGENETIC MODIFICATIONS ON POPULATION SUSTAINABILITY. THE MODEL EMULATED CHANGES IN GROWTH, MORTALITY, AND FECUNDITY IN THE F0, F1, AND F2 GENERATIONS OBSERVED IN EXPERIMENTS IN WHICH LARVAL MENIDIA BERYLLINA WERE EXPOSED TO ENVIRONMENTALLY RELEVANT CONCENTRATIONS OF BIFENTHRIN (BIF), ETHINYLESTRADIOL (EE2), LEVONORGESTREL (LV), OR TRENBOLONE (TB) IN THE PARENT GENERATION (F0) AND REARED IN CLEAN WATER UP TO THE F2 GENERATION. OUR ANALYSIS SUGGESTS POTENTIALLY DRAMATIC POPULATION-LEVEL EFFECTS OF REPEATED, CHRONIC EXPOSURES OF EARLY-LIFE STAGE FISH THAT ARE NOT CAPTURED BY MODELS NOT ACCOUNTING FOR THOSE EFFECTS. SIMULATED EXPOSURES LED TO SUBSTANTIAL DECLINES IN POPULATION ABUNDANCE (LV AND BIF) OR NEAR-EXTINCTION (EE2 AND TB) WITH THE EXACT TRAJECTORY AND TIMELINE OF POPULATION DECLINE DEPENDENT ON THE COMBINATION OF F0, F1, AND F2 EFFECTS PRODUCED BY EACH COMPOUND. EVEN ACUTE ONE-TIME EXPOSURES OF EACH COMPOUND LED TO DECLINES AND RECOVERY OVER MULTIPLE YEARS DUE TO LAGGED EPIGENETIC EFFECTS. THESE RESULTS DEMONSTRATE THE POTENTIAL FOR ENVIRONMENTALLY RELEVANT CONCENTRATIONS OF COMMONLY USED COMPOUNDS TO IMPACT THE POPULATION DYNAMICS AND SUSTAINABILITY OF AN ECOLOGICALLY RELEVANT SPECIES AND MODEL ORGANISM. 2022 17 6681 35 USING ZEBRAFISH EMBRYO BIOASSAYS TO IDENTIFY CHEMICALS MODULATING THE REGULATION OF THE EPIGENOME: A CASE STUDY WITH SIMVASTATIN. CONTAMINANTS OF EMERGING CONCERN HAVE BEEN INCREASINGLY ASSOCIATED WITH THE MODULATION OF THE EPIGENOME, LEADING TO POTENTIALLY INHERITED AND PERSISTENT IMPACTS ON APICAL ENDPOINTS. HERE, WE ADDRESS THE PERFORMANCE OF THE OECD TEST NO. 236 FET (FISH EMBRYO ACUTE TOXICITY) IN THE IDENTIFICATION OF CHEMICALS ABLE TO MODULATE THE EPIGENOME. USING ZEBRAFISH (DANIO RERIO) EMBRYOS, ACUTE AND CHRONIC EXPOSURES WERE PERFORMED WITH THE PHARMACEUTICAL, SIMVASTATIN (SIM), A WIDELY PRESCRIBED HYPOCHOLESTEROLEMIC DRUG REPORTED TO INDUCE INTER AND TRANSGENERATIONAL EFFECTS. IN THE PRESENT STUDY, THE EPIGENETIC EFFECTS OF ENVIRONMENTALLY RELEVANT CONCENTRATIONS OF SIM (FROM 8 NG/L TO 2000 NG/L) WERE ADDRESSED FOLLOWING (1) AN ACUTE EMBRYO ASSAY BASED ON OECD TEST NO. 236 FET, (2) A CHRONIC PARTIAL LIFE-CYCLE EXPOSURE USING ADULT ZEBRAFISH (90 DAYS), AND (3) F1 EMBRYOS OBTAINED FROM PARENTAL EXPOSED ANIMALS. SIMVASTATIN INDUCED SIGNIFICANT EFFECTS IN GENE EXPRESSION OF KEY EPIGENETIC BIOMARKERS (DNA METHYLATION AND HISTONE ACETYLATION/DEACETYLATION) IN THE GONADS OF EXPOSED ADULT ZEBRAFISH AND IN 80 HPF ZEBRAFISH EMBRYOS (ACUTE AND CHRONIC PARENTAL INTERGENERATIONAL EXPOSURE), ALBEIT WITH DISTINCT EFFECT PROFILES BETWEEN BIOLOGICAL SAMPLES. IN THE CHRONIC EXPOSURE, SIM IMPACTED PARTICULARLY DNA METHYLTRANSFERASE GENES IN MALES AND FEMALE GONADS, WHEREAS IN F1 EMBRYOS SIM AFFECTED MOSTLY GENES ASSOCIATED WITH HISTONE ACETYLATION/DEACETYLATION. IN THE EMBRYO ACUTE DIRECT EXPOSURE, SIM MODULATED THE EXPRESSION OF BOTH GENES INVOLVED IN DNA METHYLATION AND HISTONE DEACETYLASE. THESE FINDINGS FURTHER SUPPORT THE USE OF EPIGENETIC BIOMARKERS IN ZEBRAFISH EMBRYOS IN A HIGH THROUGHPUT APPROACH TO IDENTIFY AND PRIORITIZE EPIGENOME-MODULATING CHEMICALS. 2023 18 5964 31 TEMPORAL VARIABILITY OF GLOBAL DNA METHYLATION AND HYDROXYMETHYLATION IN BUCCAL CELLS OF HEALTHY ADULTS: ASSOCIATION WITH AIR POLLUTION. BACKGROUND: EPIGENETIC CHANGES, SUCH AS DNA METHYLATION, ARE OBSERVED IN RESPONSE TO ENVIRONMENTAL EXPOSURE AND IN THE DEVELOPMENT OF SEVERAL CHRONIC DISEASES. CONSEQUENTLY, DNA METHYLATION ALTERATIONS MIGHT SERVE AS INDICATORS OF EARLY EFFECTS. IN THIS CONTEXT, THE AIM OF THIS STUDY WAS TO ASSESS THE TEMPORAL VARIABILITY OF GLOBAL DNA METHYLATION AND HYDROXYMETHYLATION LEVELS IN BUCCAL CELLS FROM HEALTHY ADULT VOLUNTEERS. METHODS: GLOBAL DNA METHYLATION (%5MDC) AND HYDROXYMETHYLATION (%5HMDC) LEVELS IN HUMAN BUCCAL CELLS, COLLECTED FROM 26 HEALTHY ADULTS AT DIFFERENT TIME POINTS, WERE QUANTIFIED BY UPLC-MS/MS. ASSOCIATIONS BETWEEN %5MDC AND %5HMDC, RESPECTIVELY, AND SHORT-TERM EXPOSURE (1-7DAYS) TO AIR POLLUTANTS PM(2.5) AND PM(10) WERE TESTED WITH MIXED-EFFECTS MODELS INCLUDING VARIOUS COVARIATES. RESULTS/DISCUSSION: DYNAMIC SHORT-TERM CHANGES IN DNA METHYLATION AND HYDROXYMETHYLATION LEVELS IN BUCCAL CELLS WERE OBSERVED, WHICH WERE INVERSELY ASSOCIATED WITH EXPOSURE TO PM(2.5) AND PM(10). AN IQR INCREASE IN PM(2.5) OVER A 7-DAY MOVING AVERAGE PERIOD WAS SIGNIFICANTLY ASSOCIATED WITH A DECREASE OF -1.47% (-1.74%, -1.20%) AND -0.043% (-0.054%, -0.032%) IN %5MDC AND %5HMDC, RESPECTIVELY. LIKEWISE, FOR PM(10), A DECREASE OF -1.42% (-1.70, -1.13) AND -0.040% (-0.051%, -0.028%) WAS OBSERVED. CONCLUSION: GLOBAL DNA METHYLATION AND HYDROXYMETHYLATATION VARIED OVER A TIME PERIOD OF THREE WEEKS. THE OBSERVED TEMPORAL VARIABILITY WAS ASSOCIATED WITH EXPOSURE TO AMBIENT PM(2.5) AND PM(10) LEVELS. THIS SHOULD BE TAKEN INTO ACCOUNT WHEN INTERPRETING EPIGENETIC ALTERATIONS IN BUCCAL CELLS. 2018 19 1980 33 EPIGENETIC ALTERATIONS IN CYTOCHROME P450 OXIDOREDUCTASE (POR) IN SPERM OF RATS EXPOSED TO TETRAHYDROCANNABINOL (THC). AS MARIJUANA LEGALIZATION IS INCREASING, RESEARCH REGARDING POSSIBLE LONG-TERM RISKS FOR USERS AND THEIR OFFSPRING IS NEEDED. LITTLE DATA EXISTS ON EFFECTS OF PATERNAL TETRAHYDROCANNABINOL (THC) EXPOSURE PRIOR TO REPRODUCTION. THIS STUDY DETERMINED IF CHRONIC THC EXPOSURE ALTERS SPERM DNA METHYLATION (DNAM) AND IF SUCH EFFECTS ARE INTERGENERATIONALLY TRANSMITTED. ADULT MALE RATS UNDERWENT ORAL GAVAGE WITH THC OR VEHICLE CONTROL. DIFFERENTIALLY METHYLATED (DM) LOCI IN MOTILE SPERM WERE IDENTIFIED USING REDUCED REPRESENTATION BISULFITE SEQUENCING (RRBS). ANOTHER COHORT WAS INJECTED WITH VEHICLE OR THC, AND SPERM DNAM WAS ANALYZED. FINALLY, THC-EXPOSED AND CONTROL ADULT MALE RATS WERE MATED WITH THC-NAIVE FEMALES. DNAM LEVELS OF TARGET GENES IN BRAIN TISSUES OF THE OFFSPRING WERE DETERMINED BY PYROSEQUENCING. RRBS IDENTIFIED 2,940 DM CPGS MAPPING TO 627 GENES. SIGNIFICANT HYPERMETHYLATION WAS CONFIRMED (P < 0.05) FOLLOWING ORAL THC ADMINISTRATION FOR CYTOCHROME P450 OXIDOREDUCTASE (POR), INVOLVED IN TOXIN PROCESSING AND DISORDERS OF SEXUAL DEVELOPMENT. POR HYPERMETHYLATION WAS NOT OBSERVED AFTER THC INJECTION OR IN THE SUBSEQUENT GENERATION. THESE RESULTS SUPPORT THAT THC ALTERS DNAM IN SPERM AND THAT ROUTE OF EXPOSURE CAN HAVE DIFFERENTIAL EFFECTS. ALTHOUGH WE DID NOT OBSERVE EVIDENCE OF INTERGENERATIONAL TRANSMISSION OF THE DNAM CHANGE, LARGER STUDIES ARE REQUIRED TO DEFINITIVELY EXCLUDE THIS POSSIBILITY. 2020 20 5100 32 POLYCHLORINATED BIPHENYLS (PCBS) ALTER DNA METHYLATION AND GENOMIC INTEGRITY OF SHEEP FETAL CELLS IN A SIMPLIFIED IN VITRO MODEL OF PREGNANCY EXPOSURE. POLYCHLORINATED BIPHENYLS (PCBS) ARE PERSISTENT ORGANIC POLLUTANTS UBIQUITOUSLY DETECTABLE IN THE ENVIRONMENT AND IN THE FOOD CHAIN. PRENATAL EXPOSURE TO PCBS NEGATIVELY AFFECTS FETAL DEVELOPMENT AND PRODUCES LONG-TERM DETRIMENTAL EFFECTS ON CHILD HEALTH. THE PRESENT STUDY SOUGHT TO EVALUATE THE CYTOTOXIC AND GENOTOXIC EFFECTS OF CHRONIC PCB EXPOSURE ON FETAL CELLS DURING PREGNANCY. TO THIS AIM, SHEEP EMBRYONIC FIBROBLASTS (SEF) AND AMNIOCYTES (SA) WERE CULTURED IN VITRO IN THE PRESENCE OF LOW DOSES OF PCBS FOR A PERIOD OF 120DAYS, COMPARABLE TO THE FULL TERM OF OVINE PREGNANCY. CELLULAR PROLIFERATION RATES, GLOBAL DNA METHYLATION, CHROMOSOME INTEGRITY, AND MARKERS OF DNA DAMAGE WERE EVALUATED AT DIFFERENT TIME POINTS. MOREOVER, SEF TREATED WITH PCBS FOR 60DAYS WERE LEFT UNTREATED FOR ONE FURTHER MONTH AND THEN EXAMINED IN ORDER TO EVALUATE THE REVERSIBILITY OF PCB-INDUCED EPIGENETIC DEFECTS. PCB-TREATED SEF WERE MORE SENSITIVE THAN SA TREATED WITH PCBS, IN TERMS OF LOW CELL PROLIFERATION, AND INCREASED DNA DAMAGE AND GLOBAL DNA METHYLATION, WHICH WERE STILL DETECTABLE AFTER INTERRUPTION OF PCB TREATMENT. THESE DATA INDICATE THAT CHRONIC EXPOSURE OF FETAL CELLS TO PCBS CAUSES PERMANENT GENOMIC AND EPIGENETIC INSTABILITY, WHICH MAY INFLUENCE BOTH PRENATAL AND POST-NATAL GROWTH UP TO ADULTHOOD. OUR IN VITRO MODEL OFFER A SIMPLE AND CONTROLLED MEANS OF STUDYING THE EFFECTS OF DIFFERENT CONTAMINANTS ON FETAL CELLS - ONE THAT COULD SET THE STAGE FOR TARGETED IN VIVO STUDIES. 2018