1 6553 123 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 2 3042 40 GENOME-WIDE ALTERATION OF HISTONE METHYLATION PROFILES ASSOCIATED WITH COGNITIVE CHANGES IN RESPONSE TO DEVELOPMENTAL ARSENIC EXPOSURE IN MICE. INORGANIC ARSENIC IS A XENOBIOTIC ENTERING THE BODY PRIMARILY THROUGH CONTAMINATED DRINKING WATER AND FOOD. THERE ARE DEFINED MECHANISMS THAT DESCRIBE ARSENIC'S ASSOCIATION WITH INCREASED CANCER INCIDENCE, HOWEVER MECHANISMS EXPLAINING ARSENIC EXPOSURE AND NEURODEVELOPMENTAL OR AGING DISORDERS ARE POORLY DEFINED. IN RECENT YEARS, ARSENIC EFFECTS ON EPIGENOME HAVE BECOME A PARTICULAR FOCUS. WE HYPOTHESIZE THAT HUMAN RELEVANT ARSENIC EXPOSURE DURING PARTICULAR DEVELOPMENTAL WINDOWS, OR LONG-TERM EXPOSURE LATER IN LIFE INDUCE PATHOPHYSIOLOGICAL NEURAL CHANGES THROUGH EPIGENOMIC ALTERATIONS, IN PARTICULAR HISTONE METHYLATION PROFILE, MANIFESTING AS COGNITIVE DECLINE. C57BL/6 WILD-TYPE MICE WERE CONTINUALLY EXPOSED TO SODIUM ARSENITE (100 MICROG/L) IN DRINKING WATER PRIOR TO MATING THROUGH WEANING OF THE EXPERIMENTAL PROGENY. A SECOND COHORT OF AGED APP/PS MICE WERE CHRONICALLY EXPOSED TO THE SAME LEVEL OF ARSENIC. COGNITIVE TESTING, HISTOLOGICAL EXAMINATION OF BRAINS AND GENOME-WIDE METHYLATION LEVELS OF H3K4ME3 AND H3K27ME3 EXAMINED AFTER CHIP-SEQ WERE USED TO DETERMINE THE EFFECTS OF ARSENIC EXPOSURE. DEVELOPMENTAL ARSENIC EXPOSURE CAUSED SIGNIFICANTLY DIMINISHED COGNITION IN WILD-TYPE MICE. THE ANALYSIS OF CHIP-SEQ DATA AND EXPERIMENTS WITH MOUSE EMBRYONIC STEM CELLS DEMONSTRATED THAT EPIGENETIC CHANGES INDUCED BY ARSENIC EXPOSURE TRANSLATED INTO GENE EXPRESSION ALTERATIONS ASSOCIATED WITH NEURONAL DEVELOPMENT AND NEUROLOGICAL DISEASE. INCREASED HIPPOCAMPAL AMYLOID PLAQUES LEVELS OF APP/PS MICE AND COGNITIVE DECLINE PROVIDED EVIDENCE THAT ARSENIC EXPOSURE AGGRAVATED AN EXISTING ALZHEIMER'S DISEASE-LIKE PHENOTYPE. WE SHOW DEVELOPMENTAL ARSENIC EXPOSURE SIGNIFICANTLY IMPACTS HISTONE MODIFICATIONS IN BRAIN WHICH REMAIN PRESENT INTO ADULTHOOD AND PROVIDE A POTENTIAL MECHANISM BY WHICH DEVELOPMENTAL ARSENIC EXPOSURE INFLUENCES COGNITIVE FUNCTIONS. WE ALSO SHOW THAT HUMAN RELEVANT, CHRONIC ARSENIC EXPOSURE HAS DELETERIOUS EFFECTS ON ADULT APP/PS MICE AND EXACERBATES EXISTING ALZHEIMER'S DISEASE-LIKE SYMPTOMS. THE RESULTS DEMONSTRATE HOW DEVELOPMENTAL ARSENIC EXPOSURE IMPACTS THE BRAIN EPIGENOME, LEADING TO ALTERED GENE EXPRESSION LATER IN LIFE. 2022 3 1511 46 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 4 904 39 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 5 3210 36 HEALTH EFFECTS ASSOCIATED WITH PRE- AND PERINATAL EXPOSURE TO ARSENIC. INORGANIC ARSENIC IS A WELL-ESTABLISHED HUMAN CARCINOGEN, ABLE TO INDUCE GENETIC AND EPIGENETIC ALTERATIONS. MORE THAN 200 MILLION PEOPLE WORLDWIDE ARE EXPOSED TO ARSENIC CONCENTRATIONS IN DRINKING WATER EXCEEDING THE RECOMMENDED WHO THRESHOLD (10MUG/L). ADDITIONALLY, CHRONIC EXPOSURE TO LEVELS BELOW THIS THRESHOLD IS KNOWN TO RESULT IN LONG-TERM HEALTH EFFECTS IN HUMANS. THE ARSENIC-RELATED HEALTH EFFECTS IN HUMANS ARE ASSOCIATED WITH ITS BIOTRANSFORMATION PROCESS, WHEREBY THE RESULTING METABOLITES CAN INDUCE MOLECULAR DAMAGE THAT ACCUMULATES OVER TIME. THE EFFECTS DERIVED FROM THESE ALTERATIONS INCLUDE GENOMIC INSTABILITY ASSOCIATED WITH OXIDATIVE DAMAGE, ALTERATION OF GENE EXPRESSION (INCLUDING CODING AND NON-CODING RNAS), GLOBAL AND LOCALIZED EPIGENETIC REPROGRAMMING, AND HISTONE POSTTRANSLATIONAL MODIFICATIONS. THESE ALTERATIONS DIRECTLY AFFECT MOLECULAR PATHWAYS INVOLVED IN THE ONSET AND PROGRESSION OF MANY CONDITIONS THAT CAN ARISE EVEN DECADES AFTER THE EXPOSURE OCCURS. IMPORTANTLY, ARSENIC METABOLITES GENERATED DURING ITS BIOTRANSFORMATION CAN ALSO PASS THROUGH THE PLACENTAL BARRIER, RESULTING IN FETAL EXPOSURE TO THIS CARCINOGEN AT SIMILAR LEVELS TO THOSE OF THE MOTHER. AS SUCH, MORE IMMEDIATE EFFECTS OF THE ARSENIC-INDUCED MOLECULAR DAMAGE CAN BE OBSERVED AS DETRIMENTAL EFFECTS ON FETAL DEVELOPMENT, PREGNANCY, AND BIRTH OUTCOMES. IN THIS REVIEW, WE FOCUS ON THE GENETIC AND EPIGENETIC DAMAGE ASSOCIATED WITH EXPOSURE TO LOW LEVELS OF ARSENIC, PARTICULARLY THOSE AFFECTING EARLY DEVELOPMENTAL STAGES. WE ALSO PRESENT HOW THESE ALTERATIONS OCCURRING DURING EARLY LIFE CAN IMPACT THE DEVELOPMENT OF CERTAIN DISEASES IN ADULT LIFE. 2021 6 3632 32 INCORPORATING TRANSGENERATIONAL EPIGENETIC INHERITANCE INTO ECOLOGICAL RISK ASSESSMENT FRAMEWORKS. CHRONIC EXPOSURE TO ENVIRONMENTAL CONTAMINANTS CAN INDUCE HERITABLE "TRANSGENERATIONAL" MODIFICATIONS TO ORGANISMS, POTENTIALLY AFFECTING FUTURE ECOSYSTEM HEALTH AND FUNCTIONALITY. INCORPORATING TRANSGENERATIONAL EPIGENETIC HERITABILITY INTO RISK ASSESSMENT PROCEDURES HAS BEEN PREVIOUSLY SUGGESTED. HOWEVER, A CRITICAL REVIEW OF EXISTING LITERATURE YIELDED NUMEROUS STUDIES CLAIMING TRANSGENERATIONAL IMPACTS, WITH LITTLE COMPELLING EVIDENCE. THEREFORE, CONTAMINANT-INDUCED EPIGENETIC INHERITANCE MAY BE LESS COMMON THAN IS REPORTED IN THE LITERATURE. WE IDENTIFIED A NEED FOR MULTIGENERATION EPIGENETIC STUDIES THAT EXTEND BEYOND WHAT COULD BE DEEMED "DIRECT EXPOSURE" TO F1 AND F2 GAMETES AND ALSO INCLUDE SUBSEQUENT MULTIPLE NONEXPOSED GENERATIONS TO ADEQUATELY EVALUATE TRANSGENERATIONAL RECOVERY TIMES. ALSO, INCREASED EXPERIMENTAL REPLICATION IS REQUIRED TO ACCOUNT FOR THE HIGHLY VARIABLE NATURE OF EPIGENETIC RESPONSES AND APPARENT IRREPRODUCIBILITY OF CURRENT STUDIES. FURTHER, EPIGENETIC END POINTS NEED TO BE CORRELATED WITH OBSERVABLE DETRIMENTAL ORGANISM CHANGES BEFORE A NEED FOR RISK MANAGEMENT CAN BE PROPERLY DETERMINED. WE SUGGEST THAT EPIGENETIC-BASED CONTAMINANT STUDIES INCLUDE CONCENTRATIONS LOWER THAN CURRENT "EC(10-20)" OR "LOWEST OBSERVABLE EFFECT CONCENTRATIONS" FOR THE ORGANISM'S MOST SENSITIVE PHENOTYPIC END POINT, AS HIGHER CONCENTRATIONS ARE LIKELY ALREADY REGULATED. FINALLY, WE PROPOSE A REGULATORY FRAMEWORK AND OPTIMAL EXPERIMENTAL DESIGN THAT ENABLES TRANSGENERATIONAL EPIGENETIC EFFECTS TO BE ASSESSED AND INCORPORATED INTO CONVENTIONAL ECOTOXICOLOGICAL TESTING. 2017 7 5166 30 PRECONCEPTION PATERNAL ALCOHOL EXPOSURE EXERTS SEX-SPECIFIC EFFECTS ON OFFSPRING GROWTH AND LONG-TERM METABOLIC PROGRAMMING. BACKGROUND: ALTHOUGH CLINICAL DATA SUPPORT AN ASSOCIATION BETWEEN PATERNAL ALCOHOL USE AND DEFICITS IN CHILD NEUROCOGNITIVE DEVELOPMENT, THE RELATIONSHIP BETWEEN PATERNAL DRINKING AND ALCOHOL-INDUCED GROWTH PHENOTYPES REMAINS CHALLENGING TO DEFINE. USING AN ESTABLISHED MOUSE MODEL OF CHRONIC EXPOSURE, PREVIOUS WORK BY OUR GROUP HAS LINKED PRECONCEPTION PATERNAL ALCOHOL USE TO SEX-SPECIFIC PATTERNS OF FETAL GROWTH RESTRICTION AND PLACENTAL DYSFUNCTION. THE AIM OF THE PRESENT STUDY WAS TO INVESTIGATE THE LONG-TERM IMPACT OF CHRONIC PRECONCEPTION PATERNAL ALCOHOL USE ON OFFSPRING GROWTH AND METABOLIC PROGRAMMING. RESULTS: PRECONCEPTION PATERNAL ALCOHOL EXPOSURE INDUCED A PROLONGED PERIOD OF FETAL GESTATION AND AN INCREASED INCIDENCE OF INTRAUTERINE GROWTH RESTRICTION, WHICH AFFECTED THE MALE OFFSPRING TO A GREATER EXTENT THAN THE FEMALES. WHILE THE FEMALE OFFSPRING OF ETHANOL-EXPOSED MALES WERE ABLE TO MATCH THE BODY WEIGHTS OF THE CONTROLS WITHIN THE FIRST 2 WEEKS OF POSTNATAL LIFE, MALE OFFSPRING CONTINUED TO DISPLAY AN 11% REDUCTION IN WEIGHT AT 5 WEEKS OF AGE AND A 6% REDUCTION AT 8 WEEKS OF AGE. THE OBSERVED GROWTH DEFICITS ASSOCIATED WITH INSULIN HYPERSENSITIVITY IN THE MALE OFFSPRING, WHILE IN CONTRAST, FEMALES DISPLAYED A MODEST LAG IN THEIR GLUCOSE TOLERANCE TEST. THESE METABOLIC DEFECTS WERE ASSOCIATED WITH AN UP-REGULATION OF GENES WITHIN THE PRO-FIBROTIC TGF-BETA SIGNALING PATHWAY AND INCREASED LEVELS OF CELLULAR HYDROXYPROLINE WITHIN THE LIVERS OF THE MALE OFFSPRING. WE OBSERVED SUPPRESSED CYTOKINE PROFILES WITHIN THE LIVER AND PANCREAS OF BOTH THE MALE AND FEMALE OFFSPRING, WHICH CORRELATED WITH THE UP-REGULATION OF GENES IN THE LIVERX/RETINOIDX/FARNESOIDX RECEPTOR PATHWAYS. HOWEVER, PATTERNS OF GENE EXPRESSION WERE HIGHLY VARIABLE BETWEEN THE OFFSPRING OF ALCOHOL-EXPOSED SIRES. IN THE ADULT OFFSPRING OF ALCOHOL-EXPOSED MALES, WE DID NOT OBSERVE ANY DIFFERENCES IN THE ALLELIC EXPRESSION OF IGF2 OR ANY OTHER IMPRINTED GENES. CONCLUSIONS: THE IMPACT OF PATERNAL ALCOHOL USE ON CHILD DEVELOPMENT IS POORLY EXPLORED AND REPRESENTS A SIGNIFICANT GAP IN OUR UNDERSTANDING OF THE TERATOGENIC EFFECTS OF ETHANOL. OUR STUDIES IMPLICATE PATERNAL EXPOSURE HISTORY AS AN ADDITIONAL AND IMPORTANT MODIFIER OF ALCOHOL-INDUCED GROWTH PHENOTYPES AND CHALLENGE THE CURRENT MATERNAL-CENTRIC EXPOSURE PARADIGM. 2019 8 477 32 ARSENIC PROJECTS IN SE ASIA. EARLY LIFE EXPOSURE TO INORGANIC ARSENIC IS ASSOCIATED WITH A WIDE RANGE OF MALIGNANT AND CHRONIC DISEASE OUTCOMES IN HUMANS. PRENATAL ARSENIC EXPOSURE MAY GIVE RISE TO ADVERSE EFFECTS ON CHILD HEALTH AND DEVELOPMENT AS ARSENIC READILY PASSES THROUGH THE PLACENTA IN HUMAN BEINGS. THE IMPACT OF MATERNAL ARSENIC EXPOSURE ON FETAL GENE EXPRESSION WAS CONDUCTED IN PREGNANT WOMEN LIVING IN SOUTHERN THAILAND. ARSENIC EXPOSED NEWBORNS HAD SIGNIFICANTLY HIGHER LEVELS OF ARSENIC IN CORD BLOOD, AND A SET OF GENES ASSOCIATED WITH NUMEROUS BIOLOGICAL PATHWAYS, INCLUDING CELL SIGNALING, APOPTOSIS, INFLAMMATORY AND STRESS RESPONSE. A SLIGHT INCREASE IN PROMOTER METHYLATION OF P53 IN CORD BLOOD LYMPHOCYTES WHICH CORRELATED WITH ARSENIC ACCUMULATION IN NAILS WAS OBSERVED IN THESE EXPOSED NEWBORNS. A FOLLOW-UP STUDY ON THESE EXPOSED CHILDREN SHOWED A SIGNIFICANT INCREASE IN OXIDATIVE DNA DAMAGE, MEASURED AS 8-HYDROXYDEOXYGUANOSINE (8-OHDG) IN SALIVA. IN ADDITION, LEVELS OF URINARY 8-OHDG EXCRETION AND SALIVARY HOGG1 EXPRESSION WERE SIGNIFICANTLY DECREASED IN EXPOSED CHILDREN SUGGESTING A DEFECT IN REPAIR OF 8-OHDG IN ARSENIC-EXPOSED CHILDREN. OUR STUDY INDICATES THAT PRENATAL ARSENIC AND CONTINUED EXPOSURE THROUGH EARLY CHILDHOOD CAN TRIGGER VARIOUS GENETIC AND EPIGENETIC ALTERATIONS THAT MAY LEAD TO DISEASE DEVELOPMENT LATER IN LIFE. 2016 9 5773 39 SPERM MICRORNA CONTENT IS ALTERED IN A MOUSE MODEL OF MALE OBESITY, BUT THE SAME SUITE OF MICRORNAS ARE NOT ALTERED IN OFFSPRING'S SPERM. THE PREVALENCE OF OBESITY IS INCREASING WORLDWIDE AND HAS TRIPLED IN MEN OF REPRODUCTIVE AGE SINCE THE 1970S. CONCERNINGLY, OBESITY IS NOT ONLY COMORBID WITH OTHER CHRONIC DISEASES, BUT THERE IS MOUNTING EVIDENCE THAT IT INCREASES THE NON-COMMUNICABLE DISEASE LOAD IN THEIR CHILDREN (EG MORTALITY, OBESITY, AUTISM). ANIMAL STUDIES HAVE DEMONSTRATED THAT PATERNAL OBESITY INCREASES THE RISK OF METABOLIC (EG GLUCOSE METABOLISM DEFECTS, OBESITY) AND REPRODUCTIVE DISORDERS IN OFFSPRING. EPIGENETIC CHANGES WITHIN SPERM ARE CLEAR MECHANISTIC CANDIDATES THAT ARE ASSOCIATED WITH BOTH CHANGES TO THE FATHER'S ENVIRONMENT AND OFFSPRING PHENOTYPE. SPECIFICALLY THERE IS EMERGING EVIDENCE THAT A FATHER'S SPERM MICRORNA CONTENT BOTH RESPONDS TO PATERNAL ENVIRONMENTAL CUES AND ALTERS THE GENE EXPRESSION PROFILE AND SUBSEQUENT DEVELOPMENT OF THE EARLY EMBRYO. WE USED A MOUSE MODEL OF HIGH FAT DIET (HFD) INDUCED OBESITY TO INVESTIGATE WHETHER MALE OBESITY COULD MODULATE SPERM MICRORNA CONTENT. WE ALSO INVESTIGATED WHETHER THIS ALTERATION TO A FATHER'S SPERM MICRORNA CONTENT LEAD TO A SIMILAR CHANGE IN THE SPERM OF MALE OFFSPRING. OUR INVESTIGATIONS WERE INITIALLY GUIDED BY A TAQMAN PCR ARRAY, WHICH INDICATED THE DIFFERENTIAL ABUNDANCE OF 28 SPERM BORNE MICRORNAS IN HFD MICE. QPCR CONFIRMATION IN A MUCH LARGER COHORT OF FOUNDER MALES DEMONSTRATED THAT 13 OF THESE MICRORNAS WERE DIFFERENTIALLY ABUNDANT (11 UP-REGULATED; 2 DOWN-REGULATED) DUE TO HFD FEEDING. DESPITE METABOLIC AND REPRODUCTIVE PHENOTYPES ALSO BEING OBSERVED IN GRAND-OFFSPRING FATHERED VIA THE MALE OFFSPRING LINEAGE, THERE WAS NO EVIDENCE THAT ANY OF THE 13 MICRORNAS WERE ALSO DYSREGULATED IN MALE OFFSPRING SPERM. THIS WAS PRESUMABLY DUE TO THE VARIATION SEEN WITHIN BOTH GROUPS OF OFFSPRING AND SUGGESTS OTHER MECHANISMS MIGHT ACT BETWEEN OFFSPRING AND GRAND-OFFSPRING. THUS 13 SPERM BORNE MICRORNAS ARE MODULATED BY A FATHER'S HFD AND THE PRESUMED TRANSFER OF THIS ALTERED MICRORNA PAYLOAD TO THE EMBRYO AT FERTILISATION POTENTIALLY ACTS TO ALTER THE EMBRYONIC MOLECULAR MAKEUP POST-FERTILISATION, ALTERING ITS GROWTH TRAJECTORY, ULTIMATELY AFFECTING ADULT OFFSPRING PHENOTYPE AND MAY CONTRIBUTE TO PATERNAL PROGRAMMING. 2016 10 1609 35 DNA METHYLATION-INDEPENDENT GROWTH RESTRICTION AND ALTERED DEVELOPMENTAL PROGRAMMING IN A MOUSE MODEL OF PRECONCEPTION MALE ALCOHOL EXPOSURE. THE PRECONCEPTION ENVIRONMENT IS A SIGNIFICANT MODIFIER OF DYSGENESIS AND THE DEVELOPMENT OF ENVIRONMENTALLY-INDUCED DISEASE. TO DATE, FETAL ALCOHOL SPECTRUM DISORDERS (FASDS) HAVE BEEN EXCLUSIVELY ASSOCIATED WITH MATERNAL EXPOSURES, YET EMERGING EVIDENCE SUGGESTS MALE-INHERITED ALTERATIONS IN THE DEVELOPMENTAL PROGRAM OF SPERM MAY BE RELEVANT TO THE GROWTH-RESTRICTION PHENOTYPES OF THIS CONDITION. USING A MOUSE MODEL OF VOLUNTARY CONSUMPTION, WE FIND CHRONIC PRECONCEPTION MALE ETHANOL EXPOSURE ASSOCIATES WITH FETAL GROWTH RESTRICTION, DECREASED PLACENTAL EFFICIENCY, ABNORMALITIES IN CHOLESTEROL TRAFFICKING, SEX-SPECIFIC ALTERATIONS IN THE GENETIC PATHWAYS REGULATING HEPATIC FIBROSIS, AND DISRUPTIONS IN THE REGULATION OF IMPRINTED GENES. ALTERATIONS IN THE DNA METHYLATION PROFILES OF IMPRINTED LOCI HAVE BEEN IDENTIFIED IN CLINICAL STUDIES OF ALCOHOLIC SPERM, SUGGESTING THE LEGACY OF PATERNAL DRINKING MAY TRANSMIT VIA HERITABLE DISRUPTIONS IN THE REGULATION OF IMPRINTED GENES. HOWEVER, THE CAPACITY OF SPERM-INHERITED CHANGES IN DNA METHYLATION TO BROADLY TRANSMIT ENVIRONMENTALLY-INDUCED PHENOTYPES REMAINS UNCONFIRMED. USING BISULPHITE MUTAGENESIS AND SECOND-GENERATION DEEP SEQUENCING, WE FIND NO EVIDENCE TO SUGGEST THAT THESE PHENOTYPES OR ANY OF THE ASSOCIATED TRANSCRIPTIONAL CHANGES ARE LINKED TO ALTERATIONS IN THE SPERM-INHERITED DNA METHYLATION PROFILE. THESE OBSERVATIONS ARE CONSISTENT WITH RECENT STUDIES EXAMINING THE MALE TRANSMISSION OF DIET-INDUCED PHENOTYPES AND EMPHASIZE THE IMPORTANCE OF EPIGENETIC MECHANISMS OF PATERNAL INHERITANCE BEYOND DNA METHYLATION. THIS STUDY CHALLENGES THE SINGULAR IMPORTANCE OF MATERNAL ALCOHOL EXPOSURES AND SUGGESTS PATERNAL ALCOHOL ABUSE IS A SIGNIFICANT, YET OVERLOOKED EPIDEMIOLOGICAL FACTOR COMPLICIT IN THE GENESIS OF ALCOHOL-INDUCED GROWTH DEFECTS, AND MAY PROVIDE MECHANISTIC INSIGHT INTO THE FAILURE OF FASD CHILDREN TO THRIVE POSTNATALLY. 2017 11 4008 33 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 12 5168 33 PRECONCEPTIONAL PATERNAL EXPOSURE TO A SINGLE TRAUMATIC EVENT AFFECTS POSTNATAL GROWTH OF FEMALE BUT NOT MALE OFFSPRING. ALTHOUGH PRECONCEPTIONAL AND PERICONCEPTIONAL MATERNAL STRESS IS A RECOGNIZED RISK FACTOR FOR OFFSPRING NEURODEVELOPMENTAL DISTURBANCES, LESS IS KNOWN ABOUT THE RELEVANCE OF PATERNAL EXPOSURES. THESE HAVE HITHERTO BEEN INVESTIGATED MAINLY WITH RESPECT TO SUBSTANCE-INDUCED IMPAIRMENT IN THE PROGENY. IN RECENT YEARS, EXPERIENTIAL INFLUENCES ON OFFSPRING HAVE COME INTO FOCUS THROUGH GROWING INSIGHT INTO EPIGENETIC MECHANISMS SUCH AS NONGENETIC MODES OF TRANSMISSION. THE EFFECT OF CHRONIC AND/OR EARLY MANIPULATIONS IN MALES HAS BEEN STUDIED BUT MUCH LESS IS KNOWN ABOUT THE POTENTIAL IMPACT OF SINGULAR MANIPULATIONS IN OLDER INDIVIDUALS. WE INVESTIGATED THE INFLUENCE OF A STRONG STRESSOR EXPOSURE, REMINISCENT OF A TRAUMATIC EVENT, IN ADULT MALE MICE ON OFFSPRING BEHAVIOR. MALE MICE, 6 WEEKS OF AGE, RECEIVED A STRONG FOOTSHOCK AND WERE MATED TO NAIVE FEMALES SEVERAL WEEKS LATER. MALE AND FEMALE OFFSPRING WERE INVESTIGATED IN A VARIETY OF TESTS FOR ANXIETY-LIKE AND DEPRESSION-LIKE BEHAVIORS. IN ADDITION, BODYWEIGHT DEVELOPMENT WAS ASSESSED. ALTHOUGH WE DID NOT OBSERVE ANY ALTERATIONS IN ANXIETY-LIKE AND DEPRESSIVE-LIKE BEHAVIORAL INDICES, WE RECORDED REDUCED BODYWEIGHT DEVELOPMENT IN THE FEMALE OFFSPRING. OUR DATA EMPHASIZE THE RELEVANCE OF SEX AS A (CO)DETERMINANT OF OUTCOMES IN THE WAKE OF PARENTAL MANIPULATIONS. THEY FURTHER SUGGEST THAT THE WINDOW OF VULNERABILITY FOR THE INDUCTION OF PATRILINEAR EFFECTS MIGHT BE WIDER THAN THAT CURRENTLY ASSUMED. 2013 13 2472 30 EPIGENETIC TRANSMISSION OF THE IMPACT OF EARLY STRESS ACROSS GENERATIONS. BACKGROUND: TRAUMATIC EXPERIENCES IN EARLY LIFE ARE RISK FACTORS FOR THE DEVELOPMENT OF BEHAVIORAL AND EMOTIONAL DISORDERS. SUCH DISORDERS CAN PERSIST THROUGH ADULTHOOD AND HAVE OFTEN BEEN REPORTED TO BE TRANSMITTED ACROSS GENERATIONS. METHODS: TO INVESTIGATE THE TRANSGENERATIONAL EFFECT OF EARLY STRESS, MICE WERE EXPOSED TO CHRONIC AND UNPREDICTABLE MATERNAL SEPARATION FROM POSTNATAL DAY 1 TO 14. RESULTS: WE SHOW THAT CHRONIC AND UNPREDICTABLE MATERNAL SEPARATION INDUCES DEPRESSIVE-LIKE BEHAVIORS AND ALTERS THE BEHAVIORAL RESPONSE TO AVERSIVE ENVIRONMENTS IN THE SEPARATED ANIMALS WHEN ADULT. MOST OF THE BEHAVIORAL ALTERATIONS ARE FURTHER EXPRESSED BY THE OFFSPRING OF MALES SUBJECTED TO MATERNAL SEPARATION, DESPITE THE FACT THAT THESE MALES ARE REARED NORMALLY. CHRONIC AND UNPREDICTABLE MATERNAL SEPARATION ALSO ALTERS THE PROFILE OF DNA METHYLATION IN THE PROMOTER OF SEVERAL CANDIDATE GENES IN THE GERMLINE OF THE SEPARATED MALES. COMPARABLE CHANGES IN DNA METHYLATION ARE ALSO PRESENT IN THE BRAIN OF THE OFFSPRING AND ARE ASSOCIATED WITH ALTERED GENE EXPRESSION. CONCLUSIONS: THESE FINDINGS HIGHLIGHT THE NEGATIVE IMPACT OF EARLY STRESS ON BEHAVIORAL RESPONSES ACROSS GENERATIONS AND ON THE REGULATION OF DNA METHYLATION IN THE GERMLINE. 2010 14 4011 30 LOW PATERNAL DIETARY FOLATE ALTERS THE MOUSE SPERM EPIGENOME AND IS ASSOCIATED WITH NEGATIVE PREGNANCY OUTCOMES. EPIDEMIOLOGICAL STUDIES SUGGEST THAT A FATHER'S DIET CAN INFLUENCE OFFSPRING HEALTH. A PROPOSED MECHANISM FOR PATERNAL TRANSMISSION OF ENVIRONMENTAL INFORMATION IS VIA THE SPERM EPIGENOME. THE EPIGENOME INCLUDES HERITABLE INFORMATION SUCH AS DNA METHYLATION. WE HYPOTHESIZE THAT THE DIETARY SUPPLY OF METHYL DONORS WILL ALTER EPIGENETIC REPROGRAMMING IN SPERM. HERE WE FEED MALE MICE EITHER A FOLATE-DEFICIENT OR FOLATE-SUFFICIENT DIET THROUGHOUT LIFE. PATERNAL FOLATE DEFICIENCY IS ASSOCIATED WITH INCREASED BIRTH DEFECTS IN THE OFFSPRING, WHICH INCLUDE CRANIOFACIAL AND MUSCULOSKELETAL MALFORMATIONS. GENOME-WIDE DNA METHYLATION ANALYSIS AND THE SUBSEQUENT FUNCTIONAL ANALYSIS IDENTIFY DIFFERENTIAL METHYLATION IN SPERM OF GENES IMPLICATED IN DEVELOPMENT, CHRONIC DISEASES SUCH AS CANCER, DIABETES, AUTISM AND SCHIZOPHRENIA. WHILE >300 GENES ARE DIFFERENTIALLY EXPRESSED IN OFFSPRING PLACENTA, ONLY TWO CORRESPOND TO GENES WITH DIFFERENTIAL METHYLATION IN SPERM. THIS MODEL SUGGESTS EPIGENETIC TRANSMISSION MAY INVOLVE SPERM HISTONE H3 METHYLATION OR DNA METHYLATION AND THAT ADEQUATE PATERNAL DIETARY FOLATE IS ESSENTIAL FOR OFFSPRING HEALTH. 2013 15 6594 37 TUMOR-AUGMENTING EFFECTS OF GESTATIONAL ARSENIC EXPOSURE ON F1 AND F2 IN MICE. THE CONSEQUENCES OF EARLY-LIFE EXPOSURE TO CHEMICALS IN THE ENVIRONMENT ARE EMERGING CONCERNS. CHRONIC EXPOSURE TO NATURALLY OCCURRING INORGANIC ARSENIC HAS BEEN KNOWN TO CAUSE VARIOUS ADVERSE HEALTH EFFECTS, INCLUDING CANCERS, IN HUMANS. ON THE OTHER HAND, ANIMAL STUDIES BY DR. M. WAALKES' GROUP REPORTED THAT ARSENITE EXPOSURE OF PREGNANT F0 FEMALES, ONLY FROM GESTATIONAL DAY 8 TO 18, INCREASED HEPATIC TUMORS IN THE F1 (ARSENITE-F1) MALES OF C3H MICE, WHOSE MALES TEND TO DEVELOP SPONTANEOUS HEPATIC TUMORS LATER IN LIFE. SINCE THIS MICE MODEL ILLUMINATED NOVEL UNIDENTIFIED CONSEQUENCES OF ARSENIC EXPOSURE, WE WISHED TO FURTHER INVESTIGATE THE BACKGROUND MECHANISMS. IN THE SAME EXPERIMENTAL MODEL, WE IDENTIFIED A VARIETY OF FACTORS THAT WERE AFFECTED BY GESTATIONAL ARSENIC EXPOSURE, INCLUDING EPIGENETIC AND GENETIC CHANGES, AS POSSIBLE CONSTITUENTS OF MULTIPLE STEPS OF LATE-ONSET HEPATIC TUMOR AUGMENTATION IN ARSENITE-F1 MALES. FURTHERMORE, OUR STUDY DISCOVERED THAT THE F2 MALES BORN TO ARSENITE-F1 MALES DEVELOPED HEPATIC TUMORS AT A SIGNIFICANTLY HIGHER RATE THAN THE CONTROL F2 MALES. THE RESULTS IMPLY THAT THE TUMOR AUGMENTING EFFECT IS INHERITED BY ARSENITE-F2 MALES THROUGH THE SPERM OF ARSENITE-F1. IN THIS ARTICLE, WE SUMMARIZED OUR STUDIES ON THE CONSEQUENCES OF GESTATIONAL ARSENITE EXPOSURE IN F1 AND F2 MICE TO DISCUSS NOVEL ASPECTS OF BIOLOGICAL EFFECTS OF GESTATIONAL ARSENIC EXPOSURE. 2017 16 6426 35 THE TRANSGENERATIONAL TRANSMISSION OF THE PATERNAL TYPE 2 DIABETES-INDUCED SUBFERTILITY PHENOTYPE. DIABETES IS A CHRONIC METABOLIC DISORDER CHARACTERIZED BY HYPERGLYCEMIA AND ASSOCIATED WITH MANY HEALTH COMPLICATIONS DUE TO THE LONG-TERM DAMAGE AND DYSFUNCTION OF VARIOUS ORGANS. A CONSEQUENTIAL COMPLICATION OF DIABETES IN MEN IS REPRODUCTIVE DYSFUNCTION, REDUCED FERTILITY, AND POOR REPRODUCTIVE OUTCOMES. HOWEVER, THE MOLECULAR MECHANISMS RESPONSIBLE FOR DIABETIC ENVIRONMENT-INDUCED SPERM DAMAGE AND OVERALL DECREASED REPRODUCTIVE OUTCOMES ARE NOT FULLY ESTABLISHED. WE EVALUATED THE EFFECTS OF TYPE 2 DIABETES EXPOSURE ON THE REPRODUCTIVE SYSTEM AND THE REPRODUCTIVE OUTCOMES OF MALES AND THEIR MALE OFFSPRING, USING A MOUSE MODEL. WE DEMONSTRATE THAT PATERNAL EXPOSURE TO TYPE 2 DIABETES MEDIATES INTERGENERATIONAL AND TRANSGENERATIONAL EFFECTS ON THE REPRODUCTIVE HEALTH OF THE OFFSPRING, ESPECIALLY ON SPERM QUALITY, AND ON METABOLIC CHARACTERISTICS. GIVEN THE TRANSGENERATIONAL IMPAIRMENT OF REPRODUCTIVE AND METABOLIC PARAMETERS THROUGH TWO GENERATIONS, THESE CHANGES LIKELY TAKE THE FORM OF INHERITED EPIGENETIC MARKS THROUGH THE GERMLINE. OUR RESULTS EMPHASIZE THE IMPORTANCE OF IMPROVING METABOLIC HEALTH NOT ONLY IN WOMEN OF REPRODUCTIVE AGE, BUT ALSO IN POTENTIAL FATHERS, IN ORDER TO REDUCE THE NEGATIVE IMPACTS OF DIABETES ON SUBSEQUENT GENERATIONS. 2021 17 5397 33 REDUCED LEVELS OF MIRNAS 449 AND 34 IN SPERM OF MICE AND MEN EXPOSED TO EARLY LIFE STRESS. EXPOSURE OF MALE MICE TO EARLY LIFE STRESS ALTERS THE LEVELS OF SPECIFIC SPERM MIRNAS THAT PROMOTE STRESS-ASSOCIATED BEHAVIORS IN THEIR OFFSPRING. TO BEGIN TO EVALUATE WHETHER SIMILAR PHENOMENA OCCUR IN MEN, WE SEARCHED FOR SPERM MIRNA CHANGES THAT OCCUR IN BOTH MICE AND MEN EXPOSED TO EARLY LIFE STRESSORS THAT HAVE LONG-LASTING EFFECTS. FOR MEN, WE USED THE ADVERSE CHILDHOOD EXPERIENCE (ACE) QUESTIONNAIRE. IT REVEALS THE DEGREE OF ABUSIVE AND/OR DYSFUNCTIONAL FAMILY EXPERIENCES WHEN YOUNG, WHICH INCREASES RISKS OF DEVELOPING FUTURE PSYCHOLOGICAL AND PHYSICAL DISORDERS. FOR MALE MICE, WE USED ADOLESCENT CHRONIC SOCIAL INSTABILITY (CSI) STRESS, WHICH NOT ONLY ENHANCES SOCIABILITY DEFECTS FOR >1 YEAR, BUT ALSO ANXIETY AND DEFECTIVE SOCIABILITY IN FEMALE OFFSPRING FOR MULTIPLE GENERATIONS THROUGH THE MALE LINEAGE. HERE WE FOUND A STATISTICALLY SIGNIFICANT INVERSE CORRELATION BETWEEN LEVELS OF MULTIPLE MIRNAS OF THE MIR-449/34 FAMILY AND ACE SCORES OF CAUCASIAN MALES. REMARKABLY, WE FOUND MEMBERS OF THE SAME SPERM MIRNA FAMILY ARE ALSO REDUCED IN MICE EXPOSED TO CSI STRESS. THUS, FUTURE STUDIES SHOULD BE DESIGNED TO DIRECTLY TEST WHETHER REDUCED LEVELS OF THESE MIRNAS COULD BE USED AS UNBIASED INDICATORS OF CURRENT AND/OR EARLY LIFE EXPOSURE TO SEVERE STRESS. MOREOVER, AFTER MATING STRESSED MALE MICE, THESE SPERM MIRNA REDUCTIONS PERSIST IN BOTH EARLY EMBRYOS THROUGH AT LEAST THE MORULA STAGE AND IN SPERM OF MALES DERIVED FROM THEM, SUGGESTING THESE MIRNA CHANGES CONTRIBUTE TO TRANSMISSION OF STRESS PHENOTYPES ACROSS GENERATIONS. SINCE OFFSPRING OF MEN EXPOSED TO EARLY LIFE TRAUMA HAVE ELEVATED RISKS FOR PSYCHOLOGICAL DISORDERS, THESE FINDINGS RAISE THE POSSIBILITY THAT A PORTION OF THIS RISK MAY BE DERIVED FROM EPIGENETIC REGULATION OF THESE SPERM MIRNAS. 2018 18 1655 28 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 19 4496 35 MORE THAN GENES: THE ADVANCED FETAL PROGRAMMING HYPOTHESIS. MANY LINES OF DATA, INITIAL EPIDEMIOLOGIC STUDIES AS WELL AS SUBSEQUENT EXTENSIVE EXPERIMENTAL STUDIES, INDICATE THAT EARLY-LIFE EVENTS PLAY A POWERFUL ROLE IN INFLUENCING LATER SUCEPTIBILITY TO CERTAIN CHRONIC DISEASES. SUCH EVENTS MIGHT BE OVER- OR UNDERNUTRITION, EXPOSURE TO ENVIRONMENTAL TOXINS, BUT ALSO CHANGES IN HORMONES, IN PARTICULAR STRESS HORMONES. TYPICALLY, THOSE EVENTS ARE TRIGGERED BY THE ENVIRONMENTAL CHALLENGES OF THE MOTHER. HOWEVER, RECENT STUDIES HAVE SHOWN THAT PATERNAL ENVIRONMENTAL OR NUTRITIONAL FACTORS AFFECT THE PHENOTYPE OF THE OFFSPRING AS WELL. THE MATERNAL AND PATERNAL ENVIRONMENTAL FACTORS ACT ON THE PHENOTYPE OF THE OFFSPRING VIA EPIGENETIC MODIFICATION OF ITS GENOME. THE ADVANCED FETAL PROGRAMMING HYPOTHESIS PROPOSES AN ADDITIONAL NON-ENVIRONMENTALLY DRIVEN MECHANISM: MATERNAL AND ALSO PATERNAL GENES MAY INFLUENCE THE MATURATING SPERM, THE OOCYTE, AND LATER THE EMBRYO/FETUS, LEADING TO THEIR EPIGENETIC ALTERATION. THUS, THE OBSERVED PHENOTYPE OF THE OFFSPRING MAY BE ALTERED BY MATERNAL/PATERNAL GENES INDEPENDENT OF THE FETAL GENOME. MEANWHILE, SEVERAL INDEPENDENT ASSOCIATION STUDIES IN HUMANS DEALING WITH METABOLIC AND NEUROLOGICAL TRAITS ALSO SUGGEST THAT MATERNAL GENES MIGHT AFFECT THE OFFSPRING PHENOTYPE INDEPENDENT OF THE TRANSMISSION OF THAT PARTICULAR GENE TO THE OFFSPRING. CONSIDERING THE IMPLICATIONS OF THIS HYPOTHESIS, SOME CONCLUSIONS DRAWN FROM TRANSGENIC OR KNOCKOUT ANIMAL MODELS AND BASED ON THE CAUSALITY BETWEEN A GENETIC ALTERATION AND A PHENOTYPE, NEED TO BE CHALLENGED. POSSIBLE IMPLICATIONS FOR THE DEVELOPMENT, DIAGNOSTIC AND THERAPY OF HUMAN GENETIC DISEASES HAVE TO BE INVESTIGATED. 2014 20 1503 30 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