1 6681 136 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 2 4924 30 PARENTAL HYPOXIC EXPOSURE CONFERS OFFSPRING HYPOXIA RESISTANCE IN ZEBRAFISH (DANIO RERIO). PARENTAL INFLUENCES ARE A POTENTIALLY IMPORTANT COMPONENT OF TRANSGENERATIONAL TRANSFER OF PHENOTYPE IN VERTEBRATES. THIS STUDY EXAMINED HOW CHRONIC HYPOXIC EXPOSURE ON ADULT ZEBRAFISH (DANIO RERIO) AFFECTED THE PHENOTYPE OF THEIR OFFSPRING. SEPARATE ADULT POPULATIONS WERE EXPOSED TO HYPOXIA (13.1 KPA O(2)) OR NORMOXIA (21.1 KPA O(2)) FOR PERIODS RANGING FROM 1 TO 12 WEEKS. ADULTS WERE THEN RETURNED TO NORMOXIA AND BRED WITHIN EXPERIMENTAL GROUPS. ADULT FECUNDITY AND EGG CHARACTERISTICS (VOLUME OF EGG, YOLK AND PERIVITELLINE FLUID) WERE ASSESSED. SUBSEQUENTLY, LARVAL BODY LENGTH, TIME TO LOSS OF EQUILIBRIUM IN SEVERE HYPOXIA (~4 KPA O(2)), AND CRITICAL THERMAL MINIMA (CT(MIN)) AND MAXIMA (CT(MAX)) WERE MEASURED AT 6, 9, 12, 15, 18, 21 AND 60 DAYS POST-FERTILIZATION (D.P.F.). ADULT FECUNDITY WAS DEPRESSED BY HYPOXIC EXPOSURE. EGG COMPONENT VOLUMES WERE ALSO DEPRESSED IN ADULTS EXPOSED TO 1-2 WEEKS OF HYPOXIA, BUT RETURNED TO CONTROL LEVELS FOLLOWING LONGER HYPOXIC EXPOSURE. ADULT HYPOXIC EXPOSURES OF >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 3 6078 28 THE EFFECT OF CHRONIC ARSENIC EXPOSURE IN ZEBRAFISH. ARSENIC IS A PREVALENT ENVIRONMENTAL TOXIN AND A GROUP ONE HUMAN CARCINOGENIC AGENT. CHRONIC ARSENIC EXPOSURE HAS BEEN ASSOCIATED WITH MANY HUMAN DISEASES. THE AIM OF THIS STUDY IS TO EVALUATE ZEBRAFISH AS AN ANIMAL MODEL TO ASSESS ARSENIC TOXICITY IN ELEVATED LONG-TERM ARSENIC EXPOSURE. WITH PROLONGED EXPOSURE (6 MONTHS) TO VARIOUS CONCENTRATIONS OF ARSENIC FROM 50 PPB TO 300 PPB, EFFECTS OF ARSENIC ACCUMULATION IN ZEBRAFISH TISSUES, AND PHENOTYPES WERE INVESTIGATED. RESULTS SHOWED THAT THERE ARE NO SIGNIFICANT CHANGES OF ARSENIC RETENTION IN ZEBRAFISH TISSUES, AND ZEBRAFISH DID NOT EXHIBIT ANY VISIBLE TUMOR FORMATION UNDER ARSENIC EXPOSURE CONDITIONS. HOWEVER, THE ZEBRAFISH DEMONSTRATE A DYSFUNCTION IN THEIR NEUROLOGICAL SYSTEM, WHICH IS REFLECTED BY A REDUCTION OF LOCOMOTIVE ACTIVITY. MOREOVER, ELEVATED LEVELS OF THE SUPEROXIDE DISMUTASE (SOD2) PROTEIN WERE DETECTED IN THE EYE AND LIVER, SUGGESTING INCREASED OXIDATIVE STRESS. IN ADDITION, THE PROGENIES OF ARSENIC-TREATED PARENTS DISPLAYED A SMALLER BIOMASS (FOUR-FOLD REDUCTION IN BODY WEIGHT) COMPARED WITH THOSE FROM THEIR PARENTAL CONTROLS. THIS RESULT INDICATES THAT ARSENIC MAY INDUCE GENETIC OR EPIGENETIC CHANGES THAT ARE THEN PASSED ON TO THE NEXT GENERATION. OVERALL, THIS STUDY DEMONSTRATES THAT ZEBRAFISH IS A CONVENIENT VERTEBRATE MODEL WITH ADVANTAGES IN THE EVALUATION OF ARSENIC-ASSOCIATED NEUROLOGICAL DISORDERS AS WELL AS ITS INFLUENCES ON THE OFFSPRING. 2016 4 1475 22 DISTRIBUTION OF H3K27ME3, H3K9ME3, AND H3K4ME3 ALONG AUTOPHAGY-RELATED GENES HIGHLY EXPRESSED IN STARVED ZEBRAFISH MYOTUBES. THE ZEBRAFISH (DANIO RERIO) REMAINS THE TELEOST FISH OF CHOICE FOR BIOLOGICAL INVESTIGATIONS DUE TO THE VAST ARRAY OF MOLECULAR TOOLS AND RESOURCES AVAILABLE. TO BETTER UNDERSTAND THE EPIGENETIC REGULATION OF AUTOPHAGY, WE UTILIZED A PRIMARY MYOTUBE CULTURE SYSTEM GENERATED FROM ISOLATED MYOGENIC PRECURSOR CELLS (MPCS) FROM ZEBRAFISH GROWN UNDER STARVATION CONDITIONS USING A MEDIA DEVOID OF SERUM AND AMINO ACIDS. HERE, WE REPORT STARVATION-INDUCED REGULATION OF SEVERAL AUTOPHAGY-RELATED GENES (ATG) EXPRESSION AND PROFILE THE DISTRIBUTION OF H3K27ME3, H3K9ME3, AND H3K4ME3 MARKS ALONG LC3B, ATG4B AND P62/SQSTM1 LOCI. THESE DATA SUPPORT EPIGENETIC REGULATION OF AUTOPHAGY IN RESPONSE TO STARVATION THAT SUGGESTS A LEVEL OF REGULATION THAT CAN BE SUSTAINED FOR CHRONIC CONDITIONS VIA CHROMATIN MODIFICATION. 2017 5 6280 35 THE PLASTICIZER BISPHENOL A PERTURBS THE HEPATIC EPIGENOME: A SYSTEMS LEVEL ANALYSIS OF THE MIRNOME. UBIQUITOUS EXPOSURE TO BISPHENOL A (BPA), AN ENDOCRINE DISRUPTOR (ED), HAS RAISED CONCERNS FOR BOTH HUMAN AND ECOSYSTEM HEALTH. EPIGENETIC FACTORS, INCLUDING MICRORNAS (MIRNAS), ARE KEY REGULATORS OF GENE EXPRESSION DURING CANCER. THE EFFECT OF BPA EXPOSURE ON THE ZEBRAFISH EPIGENOME REMAINS POORLY CHARACTERIZED. ZEBRAFISH REPRESENTS AN EXCELLENT MODEL TO STUDY CANCER AS THE ORGANISM DEVELOPS A DISEASE THAT RESEMBLES HUMAN CANCER. USING ZEBRAFISH AS A SYSTEMS TOXICOLOGY MODEL, WE HYPOTHESIZED THAT CHRONIC BPA-EXPOSURE IMPACTS THE MIRNOME IN ADULT ZEBRAFISH AND ESTABLISHES AN EPIGENOME MORE SUSCEPTIBLE TO CANCER DEVELOPMENT. AFTER A 3 WEEK EXPOSURE TO 100 NM BPA, RNA FROM THE LIVER WAS EXTRACTED TO PERFORM HIGH THROUGHPUT MRNA AND MIRNA SEQUENCING. DIFFERENTIAL EXPRESSION (DE) ANALYSES COMPARING BPA-EXPOSED TO CONTROL SPECIMENS WERE PERFORMED USING ESTABLISHED BIOINFORMATICS PIPELINES. IN THE BPA-EXPOSED LIVER, 6188 MRNAS AND 15 MIRNAS WERE DIFFERENTLY EXPRESSED (Q