1 4923 128 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 2 1816 28 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 3 5330 34 PUTATIVE EPIGENETIC BIOMARKERS OF STRESS IN RED BLOOD CELLS OF CHICKENS REARED ACROSS DIFFERENT BIOMES. PRODUCTION ANIMALS ARE CONSTANTLY SUBJECTED TO EARLY ADVERSE ENVIRONMENTAL CONDITIONS THAT INFLUENCE THE ADULT PHENOTYPE AND PRODUCE EPIGENETIC EFFECTS. CPG DINUCLEOTIDE METHYLATION IN RED BLOOD CELLS (RBC) COULD BE A USEFUL EPIGENETIC BIOMARKER TO IDENTIFY ANIMALS SUBJECTED TO CHRONIC STRESS IN THE PRODUCTION ENVIRONMENT. HERE WE COMPARED A REDUCED FRACTION OF THE RBC METHYLOME OF CHICKENS EXPOSED TO SOCIAL ISOLATION TO NON-EXPOSED. THESE EXPERIMENTS WERE PERFORMED IN TWO DIFFERENT LOCATIONS: BRAZIL AND SWEDEN. THE AIM WAS TO IDENTIFY STRESS-ASSOCIATED DNA METHYLATION PROFILES IN RBC ACROSS THESE POPULATIONS, IN SPITE OF THE VARIABLE CONDITIONS TO WHICH BIRDS ARE EXPOSED IN EACH FACILITY AND THEIR DIFFERENT LINEAGES. BIRDS WERE INCREASINGLY EXPOSED TO A SOCIAL ISOLATION TREATMENT, COMBINED WITH FOOD AND WATER DEPRIVATION, AT RANDOM PERIODS OF THE DAY FROM WEEKS 1-4 AFTER HATCHING. WE THEN COLLECTED THE RBC DNA FROM INDIVIDUALS AND COMPARED A REDUCED FRACTION OF THEIR METHYLOME BETWEEN THE EXPERIMENTAL GROUPS USING TWO BIOINFORMATIC APPROACHES TO IDENTIFY DIFFERENTIALLY METHYLATED REGIONS (DMRS): ONE USING FIXED-SIZE WINDOWS AND ANOTHER THAT PRESELECTED DIFFERENTIAL PEAKS WITH MACS2. THREE LEVELS OF SIGNIFICANCE WERE USED (P 50%) OF SPECIFIC TRANSCRIPTION FACTOR BINDING SITES. THREE OVERLAPPING DMRS WERE FOUND BETWEEN THE BR AND SW POPULATION USING THE MOST RELAXED P-VALUE (P 1 WEEK RESULTED IN LONGER BODY LENGTHS IN THEIR LARVAL OFFSPRING. TIME TO LOSS OF EQUILIBRIUM IN SEVERE HYPOXIA (I.E. HYPOXIC RESISTANCE) IN CONTROL LARVAE DECREASED FROM 6 TO 12 D.P.F., REMAINING CONSTANT THEREAFTER. NOTABLY, HYPOXIC RESISTANCE FROM 6 TO 18 D.P.F. WAS ~15% LOWER IN LARVAE WHOSE PARENTS WERE EXPOSED TO JUST 1 WEEK OF CHRONIC HYPOXIA, BUT RESISTANCE WAS SIGNIFICANTLY INCREASED BY ~24-30% IN 6-18 D.P.F. LARVAE FROM ADULTS EXPOSED TO 2, 3 OR 4 WEEKS OF HYPOXIA. CT(MIN) (~10-12 DEGREES C) AND CT(MAX) (~39.5 DEGREES C) WERE UNCHANGED BY PARENTAL HYPOXIC EXPOSURE. THIS STUDY DEMONSTRATES THAT PARENTAL HYPOXIC EXPOSURE IN ADULT ZEBRAFISH HAS PROFOUND EPIGENETIC EFFECTS ON THE MORPHOLOGICAL AND PHYSIOLOGICAL PHENOTYPE OF THEIR OFFSPRING. 2012 14 2484 47 EPIGENETIC, TRANSCRIPTIONAL AND PHENOTYPIC RESPONSES IN TWO GENERATIONS OF DAPHNIA MAGNA EXPOSED TO THE DNA METHYLATION INHIBITOR 5-AZACYTIDINE. THE WATER FLEA DAPHNIA MAGNA IS A KEYSTONE SPECIES IN FRESHWATER ECOSYSTEMS AND HAS BEEN WIDELY USED AS A MODEL ORGANISM IN ENVIRONMENTAL ECOTOXICOLOGY. THIS AQUATIC CRUSTACEAN IS SENSITIVE TO ENVIRONMENTAL STRESSORS AND DISPLAYS CONSIDERABLE PLASTICITY IN ADAPTING TO CHANGING ENVIRONMENTAL CONDITIONS. PART OF THIS PLASTICITY MAY BE DUE TO EPIGENETIC REGULATION OF GENE EXPRESSION, INCLUDING CHANGES TO DNA METHYLATION AND HISTONE MODIFICATIONS. BECAUSE OF THE GENERALLY HYPOMETHYLATED GENOME OF THIS SPECIES, WE HYPOTHESIZED THAT THE HISTONE CODE MAY HAVE AN ESSENTIAL ROLE IN THE EPIGENETIC CONTROL AND THAT HISTONE MODIFICATIONS MIGHT BE AN EARLY MARKER FOR STRESS. THIS STUDY AIMS TO CHARACTERIZE THE EPIGENETIC, TRANSCRIPTIONAL AND PHENOTYPIC RESPONSES AND THEIR CAUSAL LINKAGES IN DIRECTLY EXPOSED ADULT (F0) DAPHNIA AND PERITONEAL EXPOSED NEONATES (F1) AFTER A CHRONIC (7-DAY) EXPOSURE TO A SUBLETHAL CONCENTRATION (10 MG/L) OF 5-AZACYTIDINE, A WELL-STUDIED VERTEBRATE DNA METHYLATION INHIBITOR. EXPOSURE OF THE F0 GENERATION SIGNIFICANTLY REDUCED THE CUMULATIVE FECUNDITY, ACCOMPANIED WITH DIFFERENTIAL EXPRESSION OF GENES IN THE ONE-CARBON-CYCLE METABOLIC PATHWAY. IN THE EPIGENOME OF THE F0 GENERATION, A DECREASE IN GLOBAL DNA METHYLATION, BUT NO SIGNIFICANT CHANGES ON H3K4ME3 OR H3K27ME3, WERE OBSERVED. IN THE F1 OFFSPRING GENERATION, CHANGES IN GENE EXPRESSION, A SIGNIFICANT REDUCTION IN GLOBAL DNA METHYLATION AND CHANGES IN HISTONE MODIFICATIONS WERE IDENTIFIED. THE RESULTS INDICATE THAT EXPOSURE DURING ADULTHOOD MAY RESULT IN MORE PRONOUNCED EFFECTS ON EARLY DEVELOPMENT IN THE OFFSPRING GENERATION, THOUGH INTERPRETATION OF THE DATA SHOULD BE CAREFULLY DONE SINCE BOTH THE EXPOSURE REGIME AND DEVELOPMENTAL PERIOD IS DIFFERENT IN THE TWO GENERATIONS EXAMINED. THE OBTAINED RESULTS IMPROVE OUR UNDERSTANDING OF CRUSTACEAN EPIGENETICS AND THE TOOLS DEVELOPED MAY PROMOTE USE OF EPIGENETIC MARKERS IN HAZARD ASSESSMENT OF ENVIRONMENTAL STRESSORS. 2019 15 166 38 ABNORMAL OVARIAN DNA METHYLATION PROGRAMMING DURING GONAD MATURATION IN WILD CONTAMINATED FISH. THERE IS INCREASING EVIDENCE THAT POLLUTANTS MAY CAUSE DISEASES VIA EPIGENETIC MODIFICATIONS. EPIGENETIC MECHANISMS SUCH AS DNA METHYLATION PARTICIPATE IN THE REGULATION OF GENE TRANSCRIPTION. SURPRISINGLY, EPIGENETICS RESEARCH IS STILL LIMITED IN ECOTOXICOLOGY. IN THIS STUDY, WE INVESTIGATED WHETHER CHRONIC EXPOSURE TO CONTAMINANTS EXPERIENCED BY WILD FEMALE FISH (ANGUILLA ANGUILLA) THROUGHOUT THEIR JUVENILE PHASE CAN AFFECT THE DNA METHYLATION STATUS OF THEIR OOCYTES DURING GONAD MATURATION. THUS, FISH WERE SAMPLED IN TWO LOCATIONS PRESENTING A LOW OR A HIGH CONTAMINATION LEVEL. THEN, FISH WERE TRANSFERRED TO THE LABORATORY AND ARTIFICIALLY MATURED. BEFORE HORMONAL TREATMENT, THE DNA METHYLATION LEVELS OF THE GENES ENCODING FOR THE AROMATASE AND THE RECEPTOR OF THE FOLLICLE STIMULATING HORMONE WERE HIGHER IN CONTAMINATED FISH THAN IN FISH FROM THE CLEAN SITE. FOR THE HORMONE RECEPTOR, THIS HYPERMETHYLATION WAS POSITIVELY CORRELATED WITH THE CONTAMINATION LEVEL OF FISH AND WAS ASSOCIATED WITH A DECREASE IN ITS TRANSCRIPTION LEVEL. IN ADDITION, WHEREAS GONAD GROWTH WAS ASSOCIATED WITH AN INCREASE IN DNA METHYLATION IN FISH FROM THE CLEAN SITE, NO CHANGES WERE OBSERVED IN CONTAMINATED FISH IN RESPONSE TO HORMONAL TREATMENT. FINALLY, A HIGHER GONAD GROWTH WAS OBSERVED IN FISH FROM THE REFERENCE SITE IN COMPARISON TO CONTAMINATED FISH. 2014 16 2698 37 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 17 6556 23 TRANSGENERATIONAL EFFECTS OF POLYETHYLENE MICROPLASTIC FRAGMENTS CONTAINING BENZOPHENONE-3 ADDITIVE IN DAPHNIA MAGNA. MATERNAL EXPOSURE TO MICROPLASTICS (MPS) PLAYS AN IMPORTANT ROLE IN THE FITNESS OF UNEXPOSED PROGENY. IN THIS STUDY, THE TRANSGENERATIONAL EFFECTS OF POLYETHYLENE MP FRAGMENTS (17.35 +/- 5.50 MICROM) CONTAINING BENZOPHENONE-3 (BP-3; 2.85 +/- 0.16% W/W) ON CHRONIC TOXICITY (21 D) IN DAPHNIA MAGNA WERE INVESTIGATED ACROSS FOUR GENERATIONS. ONLY D. MAGNA IN THE F0 GENERATION WAS EXPOSED TO MP FRAGMENTS, MP/BP-3 FRAGMENTS, AND BP-3 LEACHATE TO IDENTIFY THE TRANSGENERATIONAL EFFECT IN THE F3 GENERATION. THE MORTALITY OF D. MAGNA INDUCED BY MP AND MP/BP-3 FRAGMENTS WAS RECOVERED IN THE F3 GENERATION, BUT SOMATIC GROWTH AND REPRODUCTION SIGNIFICANTLY DECREASED COMPARED TO THE CONTROL. ADDITIONALLY, REPRODUCTION OF D. MAGNA EXPOSED TO BP-3 LEACHATE SIGNIFICANTLY DECREASED IN THE F3 GENERATION. THESE FINDINGS CONFIRMED THE TRANSGENERATIONAL EFFECTS OF MP FRAGMENT AND BP-3 ADDITIVE ON D. MAGNA. PARTICULARLY, THE ADVERSE EFFECT ON D. MAGNA REPRODUCTION SEEMED TO BE CUMULATIVE ACROSS FOUR GENERATIONS FOR MP/BP-3 FRAGMENTS, WHILE IT WAS AN ACCLIMATION TREND FOR BP-3 LEACHATE. HOWEVER, THERE WAS NO SIGNIFICANT DIFFERENCE IN GLOBAL DNA METHYLATION IN D. MAGNA ACROSS FOUR GENERATIONS, THUS REQUIRING A GENE-SPECIFIC DNA METHYLATION STUDY TO IDENTIFY DIFFERENT EPIGENETIC TRANSGENERATIONAL INHERITANCE. 2022 18 1325 26 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 19 4930 31 PATERNAL ALCOHOL EXPOSURE REDUCES ACQUISITION OF OPERANT ALCOHOL SELF-ADMINISTRATION AND AFFECTS BDNF DNA METHYLATION IN MALE AND FEMALE OFFSPRING. FAMILIAL TRANSMISSION OF ALCOHOL USE DISORDER REFLECTS GENETIC AND ENVIRONMENTAL FACTORS. PATERNAL ALCOHOL EXPOSURE MAY AFFECT RODENT OFFSPRING VIA EPIGENETIC MODIFICATIONS TRANSMITTED THROUGH THE MALE GERM LINE. WHILE SUCH EXPOSURE ALTERS ALCOHOL SENSITIVITY IN MOUSE OFFSPRING, NO STUDIES EXAMINED IF IT IMPACTS THE DEVELOPMENT OF OPERANT ALCOHOL SELF-ADMINISTRATION IN RATS. WE EXPOSED MALE (SIRES) WISTAR RATS TO CHRONIC INTERMITTENT ETHANOL IN VAPOUR CHAMBERS (16 H/DAY; 5 DAYS/WEEK) OR TO AIR FOR 6 WEEKS. EIGHT WEEKS LATER, RATS WERE MATED WITH ALCOHOL-NAIVE FEMALES. ADULT ALCOHOL- AND CONTROL-SIRED F1 OFFSPRING WERE ASSESSED IN ACQUISITION OF ALCOHOL SELF-ADMINISTRATION IN WHICH INCREASING ALCOHOL CONCENTRATIONS (2.5%, 5% AND 10%, V/V) WERE DELIVERED AFTER ONE LEVER PRESS (FIXED RATIO 1 OR FR1). PRIOR TO ALCOHOL SESSIONS, RATS WERE TRAINED TO LEVER PRESS FOR FOOD DELIVERY UNDER AN FR1 SCHEDULE OF REINFORCEMENT. DNA METHYLATION LEVELS OF THE BRAIN DERIVED NEUROTROPHIC FACTOR (BDNF) GENE WERE MEASURED IN SPERM, NUCLEUS ACCUMBENS (NAC) AND MEDIAL PREFRONTAL CORTEX (MPFC) IN SIRES AND IN OFFSPRING. ALCOHOL-EXPOSED SIRES HAD LOWER BDNF DNA METHYLATION LEVELS IN NAC AND GREATER METHYLATION LEVELS IN MPFC. ALTHOUGH THIS PATTERN WAS NOT RECAPITULATED IN OFFSPRING, ALCOHOL-SIRED OFFSPRING OF BOTH SEXES DID SHOW ABERRANT BDNF DNA METHYLATION PATTERNS COMPARED TO CONTROL-SIRED OFFSPRING. ALCOHOL-SIRED OFFSPRING SELF-ADMINISTERED LESS ALCOHOL (5% AND 10%) WITH NO GROUP DIFFERENCES IN FOOD RESPONDING. RESULTS INDICATE THAT PATERNAL ALCOHOL EXPOSURE PRIOR TO CONCEPTION PROTECTS AGAINST ALCOHOL'S INITIAL REINFORCING EFFECTS BUT THE PATTERN OF DYSREGULATED BDNF METHYLATION IN REWARD-RELATED CIRCUITRY DID NOT MIMIC CHANGES SEEN IN SIRES. 2022 20 1980 35 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