1 4398 138 MODULATION OF DNA METHYLTRANSFERASE PROFILE BY METHYL DONOR STARVATION FOLLOWED BY GAMMA IRRADIATION. DNA METHYLATION IS AN IMPORTANT EPIGENETIC MECHANISM OF TRANSCRIPTIONAL CONTROL, WHICH PLAYS AN ESSENTIAL ROLE IN MAINTAINING CELLULAR FUNCTION. ROLE OF ONE-CARBON TRANSFER AGENTS/METHYL DONORS NAMELY FOLATE, CHOLINE AND METHIONINE IN DNA METHYLATION HAS BEEN THE SUBJECT OF EXTENSIVE INVESTIGATION. THE METHYLATION PATTERN OF DNA IS ESTABLISHED DURING EMBRYOGENESIS BY DNA METHYLTRANSFERASE 3 (DNMT3) AND IS SUBSEQUENTLY MAINTAINED BY MAINTENANCE METHYLATION ACTIVITY OF THE ENZYME DNA METHYLTRANSFERASE 1 (DNMT1). IONIZING RADIATION IS KNOWN TO EXTENSIVELY DAMAGE THE DNA. SUFFICIENT DIETARY AVAILABILITY OF METHYL DONORS IS KNOWN TO CONTRIBUTE TOWARDS ONE-CARBON TRANSFER MEDIATED REPAIR OF DAMAGED DNA WHERE FOLATE IS INVOLVED IN NUCLEOTIDE BASE SYNTHESIS. IN THE PRESENT STUDY, MODIFICATION IN ACTIVITIES OF DNMT1 AND DNMT3 BY METHYL DONOR STARVATION FOLLOWED BY GAMMA-IRRADIATION WAS OBSERVED. ASSAYS WERE BASED ON THE CATALYTIC TRANSFER OF (3)H-METHYL GROUPS FROM S-ADENOSYL-L: -METHIONINE TO A DNA SUBSTRATE. EXPERIMENTS SHOWED A DOSE AND METHYL DONORS STARVATION DEPENDENT ATTENUATION IN DNMT1 ACTIVITY. ATTENUATION OF DNMT1 ACTIVITY WAS MOST SIGNIFICANT FOR DIET DEPRIVED OF ALL THE THREE-METHYL DONORS. NO SIGNIFICANT CHANGE IN NUCLEAR OR CYTOPLASMIC DNMT3 ACTIVITY WAS OBSERVED WHEN EITHER OR ALL THE THREE POSSIBLE SOURCE OF DIETARY METHYL GROUP SUPPLY WERE REMOVED. IONIZING RADIATION AND METHYL DONOR DEFICIENCY WERE OBSERVED TO ACT SYNERGISTICALLY TOWARDS INHIBITING DNMT1 ACTIVITY. PRESENT RESULTS SUGGESTED POSSIBILITY OF INTERACTION AMONG FOLATE, METHIONINE AND CHOLINE DEFICIENCY TO POTENTIATE SYMPTOMS OF IONIZING RADIATION STRESS. THESE ENZYMATIC MODIFICATIONS MIGHT CONTRIBUTE TO ALTERED DNA METHYLATION AFTER CHRONIC FEEDING OF METHYL DONOR FREE DIETS FOLLOWED BY GAMMA IRRADIATION. THESE RESULTS SUGGESTED THAT DIETARY AVAILABILITY OF METHYL DONORS AND GAMMA-RADIATION STRESS MIGHT SIGNIFICANTLY ALTER THE DNMT1 PROFILE. 2007 2 1655 27 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 3 315 36 ALCOHOL, DNA METHYLATION, AND CANCER. CANCER IS ONE OF THE MOST SIGNIFICANT DISEASES ASSOCIATED WITH CHRONIC ALCOHOL CONSUMPTION, AND CHRONIC DRINKING IS A STRONG RISK FACTOR FOR CANCER, PARTICULARLY OF THE UPPER AERODIGESTIVE TRACT, LIVER, COLORECTUM, AND BREAST. SEVERAL FACTORS CONTRIBUTE TO ALCOHOL-INDUCED CANCER DEVELOPMENT (I.E., CARCINOGENESIS), INCLUDING THE ACTIONS OF ACETALDEHYDE, THE FIRST AND PRIMARY METABOLITE OF ETHANOL, AND OXIDATIVE STRESS. HOWEVER, INCREASING EVIDENCE SUGGESTS THAT ABERRANT PATTERNS OF DNA METHYLATION, AN IMPORTANT EPIGENETIC MECHANISM OF TRANSCRIPTIONAL CONTROL, ALSO COULD BE PART OF THE PATHOGENETIC MECHANISMS THAT LEAD TO ALCOHOL-INDUCED CANCER DEVELOPMENT. THE EFFECTS OF ALCOHOL ON GLOBAL AND LOCAL DNA METHYLATION PATTERNS LIKELY ARE MEDIATED BY ITS ABILITY TO INTERFERE WITH THE AVAILABILITY OF THE PRINCIPAL BIOLOGICAL METHYL DONOR, S-ADENOSYLMETHIONINE (SAME), AS WELL AS PATHWAYS RELATED TO IT. SEVERAL MECHANISMS MAY MEDIATE THE EFFECTS OF ALCOHOL ON DNA METHYLATION, INCLUDING REDUCED FOLATE LEVELS AND INHIBITION OF KEY ENZYMES IN ONE-CARBON METABOLISM THAT ULTIMATELY LEAD TO LOWER SAME LEVELS, AS WELL AS INHIBITION OF ACTIVITY AND EXPRESSION OF ENZYMES INVOLVED IN DNA METHYLATION (I.E., DNA METHYLTRANSFERASES). FINALLY, VARIATIONS (I.E., POLYMORPHISMS) OF SEVERAL GENES INVOLVED IN ONE-CARBON METABOLISM ALSO MODULATE THE RISK OF ALCOHOL-ASSOCIATED CARCINOGENESIS. 2013 4 5067 31 PHYSICAL ACTIVITY AND DNA METHYLATION IN HUMANS. PHYSICAL ACTIVITY IS A STRONG STIMULUS INFLUENCING THE OVERALL PHYSIOLOGY OF THE HUMAN BODY. EXERCISES LEAD TO BIOCHEMICAL CHANGES IN VARIOUS TISSUES AND EXERT AN IMPACT ON GENE EXPRESSION. EXERCISE-INDUCED CHANGES IN GENE EXPRESSION MAY BE MEDIATED BY EPIGENETIC MODIFICATIONS, WHICH REARRANGE THE CHROMATIN STRUCTURE AND THEREFORE MODULATE ITS ACCESSIBILITY FOR TRANSCRIPTION FACTORS. ONE OF SUCH EPIGENETIC MARK IS DNA METHYLATION THAT INVOLVES AN ATTACHMENT OF A METHYL GROUP TO THE FIFTH CARBON OF CYTOSINE RESIDUE PRESENT IN CG DINUCLEOTIDES (CPG). DNA METHYLATION IS CATALYZED BY A FAMILY OF DNA METHYLTRANSFERASES. THIS REVERSIBLE DNA MODIFICATION RESULTS IN THE RECRUITMENT OF PROTEINS CONTAINING METHYL BINDING DOMAIN AND FURTHER TRANSCRIPTIONAL CO-REPRESSORS LEADING TO THE SILENCING OF GENE EXPRESSION. THE ACCUMULATION OF CPG DINUCLEOTIDES, REFERRED AS CPG ISLANDS, OCCURS AT THE PROMOTER REGIONS IN A GREAT MAJORITY OF HUMAN GENES. THEREFORE, CHANGES IN DNA METHYLATION PROFILE AFFECT THE TRANSCRIPTION OF MULTIPLE GENES. A GROWING BODY OF EVIDENCE INDICATES THAT EXERCISE TRAINING MODULATES DNA METHYLATION IN MUSCLES AND ADIPOSE TISSUE. SOME OF THESE EPIGENETIC MARKERS WERE ASSOCIATED WITH A REDUCED RISK OF CHRONIC DISEASES. THIS REVIEW SUMMARIZES THE CURRENT KNOWLEDGE ABOUT THE INFLUENCE OF PHYSICAL ACTIVITY ON THE DNA METHYLATION STATUS IN HUMANS. 2021 5 4224 30 METHYLATION CHANGES IN MUSCLE AND LIVER TISSUES OF MALE AND FEMALE MICE EXPOSED TO ACUTE AND CHRONIC LOW-DOSE X-RAY-IRRADIATION. THE BIOLOGICAL AND GENETIC EFFECTS OF CHRONIC LOW-DOSE RADIATION (LDR) EXPOSURE AND ITS RELATIONSHIP TO CARCINOGENESIS HAVE RECEIVED A LOT OF ATTENTION IN THE RECENT YEARS. FOR EXAMPLE, RADIATION-INDUCED GENOME INSTABILITY, WHICH IS THOUGHT TO BE A PRECURSOR OF TUMOROGENESIS, WAS SHOWN TO HAVE A TRANSGENERATIONAL NATURE. THIS INDICATES A POSSIBLE INVOLVEMENT OF EPIGENETIC MECHANISMS IN LDR-INDUCED GENOME INSTABILITY. GENOMIC DNA METHYLATION IS ONE OF THE MOST IMPORTANT EPIGENETIC MECHANISMS. EXISTING DATA ON RADIATION EFFECTS ON DNA METHYLATION PATTERNS IS LIMITED, AND NO ONE HAS SPECIFICALLY STUDIED THE EFFECTS OF THE LDR. WE REPORT THE FIRST STUDY OF THE EFFECTS OF WHOLE-BODY LDR EXPOSURE ON GLOBAL GENOME METHYLATION IN MUSCLE AND LIVER TISSUES OF MALE AND FEMALE MICE. IN PARALLEL, WE EVALUATED CHANGES IN PROMOTER METHYLATION AND EXPRESSION OF THE TUMOR SUPPRESSOR GENE P16(INKA) AND DNA REPAIR GENE O(6)-METHYLGUANINE-DNA METHYLTRANSFERASE (MGMT). WE OBSERVED DIFFERENT PATTERNS OF RADIATION-INDUCED GLOBAL GENOME DNA METHYLATION IN THE LIVER AND MUSCLE OF EXPOSED MALES AND FEMALES. WE ALSO FOUND SEX AND TISSUE-SPECIFIC DIFFERENCES IN P16(INKA) PROMOTER METHYLATION UPON LDR EXPOSURE. IN MALE LIVER TISSUE, P16(INKA) PROMOTER METHYLATION WAS MORE PRONOUNCED THAN IN FEMALE TISSUE. IN CONTRAST, NO SIGNIFICANT RADIATION-INDUCED CHANGES IN P16(INKA) PROMOTER METHYLATION WERE NOTED IN THE MUSCLE TISSUE OF EXPOSED MALES AND FEMALES. RADIATION ALSO DID NOT SIGNIFICANTLY AFFECT METHYLATION STATUS OF MGMT PROMOTER. WE ALSO OBSERVED SUBSTANTIAL SEX DIFFERENCES IN ACUTE AND CHRONIC RADIATION-INDUCED EXPRESSION OF P16(INKA) AND MGMT GENES. ANOTHER IMPORTANT OUTCOME OF OUR STUDY WAS THE FACT THAT CHRONIC LOW-DOSE RADIATION EXPOSURE PROVED TO BE A MORE POTENT INDUCER OF EPIGENETIC EFFECTS THAN THE ACUTE EXPOSURE. THIS SUPPORTS PREVIOUS FINDINGS THAT CHRONIC EXPOSURE LEADS TO GREATER GENOME DESTABILIZATION THAN ACUTE EXPOSURE. 2004 6 3836 31 IONIZING RADIATION POTENTIATES HIGH-FAT DIET-INDUCED INSULIN RESISTANCE AND REPROGRAMS SKELETAL MUSCLE AND ADIPOSE PROGENITOR CELLS. EXPOSURE TO IONIZING RADIATION INCREASES THE RISK OF CHRONIC METABOLIC DISORDERS SUCH AS INSULIN RESISTANCE AND TYPE 2 DIABETES LATER IN LIFE. WE HYPOTHESIZED THAT IRRADIATION REPROGRAMS THE EPIGENOME OF METABOLIC PROGENITOR CELLS, WHICH COULD ACCOUNT FOR IMPAIRED METABOLISM AFTER CANCER TREATMENT. C57BL/6 MICE WERE TREATED WITH A SINGLE DOSE OF IRRADIATION AND SUBJECTED TO HIGH-FAT DIET (HFD). RNA SEQUENCING AND REDUCED REPRESENTATION BISULFITE SEQUENCING WERE USED TO CREATE TRANSCRIPTOMIC AND EPIGENOMIC PROFILES OF PREADIPOCYTES AND SKELETAL MUSCLE SATELLITE CELLS COLLECTED FROM IRRADIATED MICE. MICE SUBJECTED TO TOTAL BODY IRRADIATION SHOWED ALTERATIONS IN GLUCOSE METABOLISM AND, WHEN CHALLENGED WITH HFD, MARKED HYPERINSULINEMIA. INSULIN SIGNALING WAS CHRONICALLY DISRUPTED IN SKELETAL MUSCLE AND ADIPOSE PROGENITOR CELLS COLLECTED FROM IRRADIATED MICE AND DIFFERENTIATED IN CULTURE. EPIGENOMIC PROFILING OF SKELETAL MUSCLE AND ADIPOSE PROGENITOR CELLS FROM IRRADIATED ANIMALS REVEALED SUBSTANTIAL DNA METHYLATION CHANGES, NOTABLY FOR GENES REGULATING THE CELL CYCLE, GLUCOSE/LIPID METABOLISM, AND EXPRESSION OF EPIGENETIC MODIFIERS. OUR RESULTS SHOW THAT TOTAL BODY IRRADIATION ALTERS INTRACELLULAR SIGNALING AND EPIGENETIC PATHWAYS REGULATING CELL PROLIFERATION AND DIFFERENTIATION OF SKELETAL MUSCLE AND ADIPOSE PROGENITOR CELLS AND PROVIDE A POSSIBLE MECHANISM BY WHICH IRRADIATION USED IN CANCER TREATMENT INCREASES THE RISK FOR METABOLIC DISEASE LATER IN LIFE. 2016 7 318 32 ALCOHOL-INDUCED EPIGENETIC CHANGES IN CANCER. CHRONIC, HEAVY ALCOHOL CONSUMPTION IS ASSOCIATED WITH SERIOUS NEGATIVE HEALTH EFFECTS, INCLUDING THE DEVELOPMENT OF SEVERAL CANCER TYPES. ONE OF THE PATHWAYS AFFECTED BY ALCOHOL TOXICITY IS THE ONE-CARBON METABOLISM. THE ALCOHOL-INDUCED IMPAIRMENT OF THIS METABOLIC PATHWAY RESULTS IN EPIGENETIC CHANGES ASSOCIATED WITH CANCER DEVELOPMENT. THESE EPIGENETIC CHANGES ARE INDUCED BY FOLATE DEFICIENCY AND BY PRODUCTS OF THE ETHANOL METABOLISM. THE CHANGES INDUCED BY LONG-TERM HEAVY ETHANOL CONSUMPTION RESULT IN ELEVATIONS OF HOMOCYSTEINE AND S-ADENOSYL-HOMOCYSTEINE (SAH) AND REDUCTIONS IN S-ADENOSYLMETHIONINE (SAM) AND ANTIOXIDANT GLUTATHIONE (GSH) LEVELS, LEADING TO ABNORMAL PROMOTER GENE HYPERMETHYLATION, GLOBAL HYPOMETHYLATION, AND METABOLIC INSUFFICIENCY OF ANTIOXIDANT DEFENSE MECHANISMS. IN ADDITION, REACTIVE OXYGEN SPECIES (ROS) GENERATED DURING THE ETHANOL METABOLISM INDUCE ALTERATIONS IN DNA METHYLATION PATTERNS THAT PLAY A CRITICAL ROLE IN CANCER DEVELOPMENT. SPECIFIC EPIGENETIC CHANGES IN ESOPHAGEAL, HEPATIC, AND COLORECTAL CANCERS HAVE BEEN DETECTED IN BLOOD SAMPLES AND PROPOSED TO BE USED CLINICALLY AS EPIGENETIC BIOMARKERS FOR DIAGNOSIS AND PROGNOSIS OF THESE CANCERS. ALSO, GENETIC VARIANTS OF GENES INVOLVED IN ONE-CARBON METABOLISM AND ETHANOL METABOLISM WERE FOUND TO MODULATE THE RELATIONSHIP BETWEEN ALCOHOL-INDUCED EPIGENETIC CHANGES AND CANCER RISK. FURTHERMORE, ALCOHOL METABOLISM PRODUCTS HAVE BEEN ASSOCIATED WITH AN INCREASE IN NADH LEVELS, WHICH LEAD TO HISTONE MODIFICATIONS AND CHANGES IN GENE EXPRESSION THAT IN TURN INFLUENCE CANCER SUSCEPTIBILITY. CHRONIC EXCESSIVE USE OF ALCOHOL ALSO AFFECTS SELECTED MEMBERS OF THE FAMILY OF MICRORNAS, AND AS MIRNAS COULD ACT AS EPIGENETIC REGULATORS, THIS MAY PLAY AN IMPORTANT ROLE IN CARCINOGENESIS. IN CONCLUSION, TARGETING ALCOHOL-INDUCED EPIGENETIC CHANGES IN SEVERAL CANCER TYPES COULD MAKE AVAILABLE CLINICAL TOOLS FOR THE DIAGNOSIS, PROGNOSIS, AND TREATMENT OF THESE CANCERS, WITH AN IMPORTANT ROLE IN PRECISION MEDICINE. 2018 8 4683 46 NEW PERSPECTIVES ON FOLATE TRANSPORT IN RELATION TO ALCOHOLISM-INDUCED FOLATE MALABSORPTION--ASSOCIATION WITH EPIGENOME STABILITY AND CANCER DEVELOPMENT. FOLATES ARE MEMBERS OF THE B-CLASS OF VITAMINS, WHICH ARE REQUIRED FOR THE SYNTHESIS OF PURINES AND PYRIMIDINES, AND FOR THE METHYLATION OF ESSENTIAL BIOLOGICAL SUBSTANCES, INCLUDING PHOSPHOLIPIDS, DNA, AND NEUROTRANSMITTERS. FOLATES CANNOT BE SYNTHESIZED DE NOVO BY MAMMALS; HENCE, AN EFFICIENT INTESTINAL ABSORPTION PROCESS IS REQUIRED. INTESTINAL FOLATE TRANSPORT IS CARRIER-MEDIATED, PH-DEPENDENT AND ELECTRONEUTRAL, WITH SIMILAR AFFINITY FOR OXIDIZED AND REDUCED FOLIC ACID DERIVATIVES. THE VARIOUS TRANSPORTERS, I.E. REDUCED FOLATE CARRIER, PROTON-COUPLED FOLATE TRANSPORTER, FOLATE-BINDING PROTEIN, AND ORGANIC ANION TRANSPORTERS, ARE INVOLVED IN THE FOLATE TRANSPORT PROCESS IN VARIOUS TISSUES. ANY IMPAIRMENT IN UPTAKE OF FOLATE CAN LEAD TO A STATE OF FOLATE DEFICIENCY, THE MOST PREVALENT VITAMIN DEFICIENCY IN WORLD, AFFECTING 10% OF THE POPULATION IN THE USA. SUCH IMPAIRMENTS IN FOLATE TRANSPORT OCCUR IN A VARIETY OF CONDITIONS, INCLUDING CHRONIC USE OF ETHANOL, SOME INBORN HEREDITARY DISORDERS, AND CERTAIN DISEASES. AMONG THESE, ETHANOL INGESTION HAS BEEN THE MAJOR CONTRIBUTOR TO FOLATE DEFICIENCY. ETHANOL-ASSOCIATED FOLATE DEFICIENCY CAN DEVELOP BECAUSE OF DIETARY INADEQUACY, INTESTINAL MALABSORPTION, ALTERED HEPATOBILIARY METABOLISM, ENHANCED COLONIC METABOLISM, AND INCREASED RENAL EXCRETION. ETHANOL REDUCES THE INTESTINAL AND RENAL UPTAKE OF FOLATE BY ALTERING THE BINDING AND TRANSPORT KINETICS OF FOLATE TRANSPORT SYSTEMS. ALSO, ETHANOL REDUCES THE EXPRESSION OF FOLATE TRANSPORTERS IN BOTH INTESTINE AND KIDNEY, AND THIS MIGHT BE A CONTRIBUTING FACTOR FOR FOLATE MALABSORPTION, LEADING TO FOLATE DEFICIENCY. THE MAINTENANCE OF INTRACELLULAR FOLATE HOMEOSTASIS IS ESSENTIAL FOR THE ONE-CARBON TRANSFER REACTIONS NECESSARY FOR DNA SYNTHESIS AND BIOLOGICAL METHYLATION REACTIONS. DNA METHYLATION IS AN IMPORTANT EPIGENETIC DETERMINANT IN GENE EXPRESSION, IN THE MAINTENANCE OF DNA INTEGRITY AND STABILITY, IN CHROMOSOMAL MODIFICATIONS, AND IN THE DEVELOPMENT OF MUTATIONS. ETHANOL, A TOXIN THAT IS CONSUMED REGULARLY, HAS BEEN FOUND TO AFFECT THE METHYLATION OF DNA. IN ADDITION TO ITS EFFECT ON DNA METHYLATION DUE TO FOLATE DEFICIENCY, ETHANOL COULD DIRECTLY EXERT ITS EFFECT THROUGH ITS INTERACTION WITH ONE-CARBON METABOLISM, IMPAIRMENT OF METHYL GROUP SYNTHESIS, AND AFFECTING THE ENZYMES REGULATING THE SYNTHESIS OF S-ADENOSYLMETHIONINE, THE PRIMARY METHYL GROUP DONOR FOR MOST BIOLOGICAL METHYLATION REACTIONS. THUS, ETHANOL PLAYS AN IMPORTANT ROLE IN THE PATHOGENESIS OF SEVERAL DISEASES THROUGH ITS POTENTIAL ABILITY TO MODULATE THE METHYLATION OF BIOLOGICAL MOLECULES. THIS REVIEW DISCUSSES THE UNDERLYING MECHANISM OF FOLATE MALABSORPTION IN ALCOHOLISM, THE MECHANISM OF METHYLATION-ASSOCIATED SILENCING OF GENES, AND HOW THE INTERACTION BETWEEN ETHANOL AND FOLATE DEFICIENCY AFFECTS THE METHYLATION OF GENES, THEREBY MODULATING EPIGENOME STABILITY AND THE RISK OF CANCER. 2009 9 2833 25 FOLATE AND DNA METHYLATION: A REVIEW OF MOLECULAR MECHANISMS AND THE EVIDENCE FOR FOLATE'S ROLE. DNA METHYLATION IS AN EPIGENETIC MODIFICATION CRITICAL TO NORMAL GENOME REGULATION AND DEVELOPMENT. THE VITAMIN FOLATE IS A KEY SOURCE OF THE ONE CARBON GROUP USED TO METHYLATE DNA. BECAUSE NORMAL MAMMALIAN DEVELOPMENT IS DEPENDENT ON DNA METHYLATION, THERE IS ENORMOUS INTEREST IN ASSESSING THE POTENTIAL FOR CHANGES IN FOLATE INTAKE TO MODULATE DNA METHYLATION BOTH AS A BIOMARKER FOR FOLATE STATUS AND AS A MECHANISTIC LINK TO DEVELOPMENTAL DISORDERS AND CHRONIC DISEASES INCLUDING CANCER. THIS REVIEW HIGHLIGHTS THE ROLE OF DNA METHYLATION IN NORMAL GENOME FUNCTION, HOW IT CAN BE ALTERED, AND THE EVIDENCE OF THE ROLE OF FOLATE/FOLIC ACID IN THESE PROCESSES. 2012 10 2297 32 EPIGENETIC REGULATION OF ACUTE INFLAMMATORY PAIN. ACUTE PAIN IS ASSOCIATED WITH TISSUE DAMAGE, WHICH RESULTS IN THE RELEASE OF INFLAMMATORY MEDIATORS. RECENT STUDIES POINT TO THE INVOLVEMENT OF EPIGENETIC MECHANISMS (DNA METHYLATION) IN THE DEVELOPMENT OF PAIN. WE HAVE FOUND THAT DURING ACUTE INFLAMMATORY PAIN INDUCED BY THE APPLICATION OF 10% MUSTARD OIL ON THE TONGUES OF RATS, LEVELS OF DNMT3A AND 3B WERE ELEVATED MARKEDLY (36 AND 42 % RESPECTIVELY), WHEREAS THE LEVEL OF DNMT1 WAS NOT CHANGED SIGNIFICANTLY. PREVIOUS INJECTION OF XEFOCAM WITH 0,4 MG/KG DOSE DECREASED LEVELS OF DNMT3A AND 3B (25 AND 24% RESPECTIVELY). THE LEVEL OF DNMT1 WAS NOT CHANGED SIGNIFICANTLY COMPARED TO THE CONTROL GROUP. THE FINDINGS SUPPORT THE IDEA THAT INHIBITORS OF DNA-METHYLTRANSFERASES COULD BE USEFUL FOR PAIN MANAGEMENT. OUR DATA SUGGEST THAT NSAIDS (ALONE OR IN COMBINATION WITH DNMT INHIBITORS) MAY BE PROPOSED AS POSSIBLE EPIGENETIC REGULATORY AGENTS, WHICH MAY PLAY A ROLE IN EPIGENETIC MECHANISMS INDIRECTLY THROUGH ALTERING THE ACTIVITY OF INFLAMMATORY MEDIATORS INVOLVED IN PAIN DEVELOPMENT. 2014 11 4604 28 NEGATIVE EVIDENCE FOR A FUNCTIONAL ROLE OF NEURONAL DNMT3A IN PERSISTENT PAIN. TRADITIONALLY, NEUROSCIENCE HAS HAD TO RELY ON MIXED TISSUE ANALYSIS TO EXAMINE TRANSCRIPTIONAL AND EPIGENETIC CHANGES IN THE CONTEXT OF NERVOUS SYSTEM FUNCTION OR PATHOLOGY. HOWEVER, PARTICULARLY WHEN STUDYING CHRONIC PAIN CONDITIONS, THIS APPROACH CAN BE FLAWED, SINCE IT NEGLECTS TO TAKE INTO ACCOUNT THE SHIFTING CONTRIBUTION OF DIFFERENT CELL TYPES ACROSS EXPERIMENTAL CONDITIONS. HERE, WE DEMONSTRATE THIS USING THE EXAMPLE OF DNA METHYLTRANSFERASES (DNMTS) - A GROUP OF EPIGENETIC MODIFIERS CONSISTING OF DNMT1, DNMT3A, AND DNMT3B IN MAMMALIAN CELLS. WE USED SENSORY NEURON-SPECIFIC KNOCKOUT MICE FOR DNMT3A/3B AS WELL AS PHARMACOLOGICAL BLOCKADE OF DNMT1 TO STUDY THEIR ROLE IN NOCICEPTION. IN CONTRAST TO PREVIOUS ANALYSES ON WHOLE TISSUE, WE FIND THAT DNMT3A AND 3B PROTEIN IS NOT EXPRESSED IN ADULT DRG NEURONS, THAT NONE OF THE DNA METHYLTRANSFERASES ARE REGULATED WITH INJURY AND THAT INTERFERING WITH THEIR FUNCTION HAS NO EFFECT ON NOCICEPTION. OUR RESULTS THEREFORE CURRENTLY DO NOT SUPPORT A ROLE FOR NEURONAL DNA METHYLTRANSFERASES IN PAIN PROCESSING IN ADULT ANIMALS. 2018 12 990 35 CHRONIC SOCIAL STRESS INDUCES DNA METHYLATION CHANGES AT AN EVOLUTIONARY CONSERVED INTERGENIC REGION IN CHROMOSOME X. CHRONIC STRESS RESULTING FROM PROLONGED EXPOSURE TO NEGATIVE LIFE EVENTS INCREASES THE RISK OF MOOD AND ANXIETY DISORDERS. ALTHOUGH CHRONIC STRESS CAN CHANGE GENE EXPRESSION RELEVANT FOR BEHAVIOR, MOLECULAR REGULATORS OF THIS CHANGE HAVE NOT BEEN FULLY DETERMINED. ONE PROCESS THAT COULD PLAY A ROLE IS DNA METHYLATION, AN EPIGENETIC PROCESS WHEREBY A METHYL GROUP IS ADDED ONTO NUCLEOTIDES, PREDOMINANTLY CYTOSINE IN THE CPG CONTEXT, AND WHICH CAN BE INDUCED BY CHRONIC STRESS. IT IS UNKNOWN TO WHAT EXTENT CHRONIC SOCIAL DEFEAT, A MODEL OF HUMAN SOCIAL STRESS, INFLUENCES DNA METHYLATION PATTERNS ACROSS THE GENOME. OUR STUDY ADDRESSED THIS QUESTION BY USING A TARGETED-CAPTURE APPROACH CALLED METHYL-SEQ TO INVESTIGATE DNA METHYLATION PATTERNS OF THE DENTATE GYRUS AT PUTATIVE REGULATORY REGIONS ACROSS THE MOUSE GENOME FROM MICE EXPOSED TO 14 DAYS OF SOCIAL DEFEAT. FINDINGS WERE REPLICATED IN INDEPENDENT COHORTS BY BISULFITE-PYROSEQUENCING. TWO DIFFERENTIALLY METHYLATED REGIONS (DMRS) WERE IDENTIFIED. ONE DMR WAS LOCATED AT INTRON 9 OF DROSHA, AND IT SHOWED REDUCED METHYLATION IN STRESSED MICE. THIS OBSERVATION REPLICATED IN ONE OF TWO INDEPENDENT COHORTS. A SECOND DMR WAS IDENTIFIED AT AN INTERGENIC REGION OF CHROMOSOME X, AND METHYLATION IN THIS REGION WAS INCREASED IN STRESSED MICE. THIS METHYLATION DIFFERENCE REPLICATED IN TWO INDEPENDENT COHORTS AND IN MAJOR DEPRESSIVE DISORDER (MDD) POSTMORTEM BRAINS. THESE RESULTS HIGHLIGHT A REGION NOT PREVIOUSLY KNOWN TO BE DIFFERENTIALLY METHYLATED BY CHRONIC SOCIAL DEFEAT STRESS AND WHICH MAY BE INVOLVED IN MDD. 2018 13 2417 27 EPIGENETIC SIGNATURE OF CHRONIC CEREBRAL HYPOPERFUSION AND BENEFICIAL EFFECTS OF S-ADENOSYLMETHIONINE IN RATS. CHRONIC CEREBRAL HYPOPERFUSION IS ASSOCIATED WITH COGNITIVE DECLINE IN AGING AND AGE-RELATED NEURODEGENERATIVE DISEASE. EPIGENETIC MECHANISMS ARE INVOLVED IN THE MAINTENANCE OF LONG-TERM HYPOXIA-ADAPTED CELLULAR PHENOTYPES. IN THE PRESENT STUDY, THE EPIGENETIC SIGNATURES SUCH AS DNA METHYLATION AND HISTONE ACETYLATION, AS WELL AS S-ADENOSYLMETHIONINE (SAM) CYCLE USING CHRONIC CEREBRAL HYPOPERFUSION RAT MODEL WERE EXPLORED. CHRONIC CEREBRAL HYPOXIA-INDUCED GLOBAL DNA HYPERMETHYLATION ASSOCIATED WITH THE INCREASE OF DNA METHYLTRANSFERASE (DNMT) 3A AS WELL AS ALTERATION OF SAM CYCLE. MEANWHILE, AN ENHANCED LEVEL OF GLOBAL HISTONE H4 ACETYLATION ACCOMPANIED WITH THE UPREGULATION OF HISTONE ACETYLTRANSFERASE, P300/CREB-BINDING PROTEIN (CBP), AND THE DOWNREGULATION OF HISTONE DEACETYLASES (HDACS), WAS ALSO OBSERVED. SAM COULD IMPROVE SPATIAL CAPACITY THROUGH THE UPREGULATION OF ACETYLCHOLINE AND BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) RATHER THAN ALTERATION OF DNA METHYLATION LEVELS. IN CONCLUSION, WE HAVE DEMONSTRATED A GENOME-WIDE ADJUSTMENT OF DNA METHYLATION AND HISTONE ACETYLATION UNDER CHRONIC CEREBRAL HYPOXIC CONDITIONS IN A RAT'S BRAIN. THESE EPIGENETIC SIGNATURES MAY REPRESENT AN ADDITIONAL MECHANISM TO PROMOTE AND MAINTAIN A HYPOXIC-ADAPTED CELLULAR RESPONDS WITH A POTENTIAL ROLE IN MEMORY DEFICITS. 2014 14 4219 41 METHYL-DONOR DEFICIENCY IN ADOLESCENCE AFFECTS MEMORY AND EPIGENETIC STATUS IN THE MOUSE HIPPOCAMPUS. DNA METHYLATION IS ONE OF THE ESSENTIAL FACTORS IN THE CONTROL OF GENE EXPRESSION. ALTERATION OF THE DNA METHYLATION PATTERN HAS BEEN LINKED TO VARIOUS NEUROLOGICAL, BEHAVIORAL AND NEUROCOGNITIVE DYSFUNCTIONS. RECENT STUDIES HAVE POINTED OUT THE IMPORTANCE OF EPIGENETICS IN BRAIN DEVELOPMENT AND FUNCTIONS INCLUDING LEARNING AND MEMORY. NUTRIENTS RELATED TO ONE-CARBON METABOLISM ARE KNOWN TO PLAY IMPORTANT ROLES IN THE MAINTENANCE OF GENOMIC DNA METHYLATION. PREVIOUS STUDIES HAVE SHOWN THAT THE LONG-TERM ADMINISTRATION OF A DIET LACKING ESSENTIAL ONE-CARBON NUTRIENTS SUCH AS METHIONINE, CHOLINE AND FOLIC ACID (METHYL DONORS) CAUSED GLOBAL DNA HYPERMETHYLATION IN THE BRAIN. THEREFORE, THE LONG-TERM FEEDING OF A METHYL-DONOR-DEFICIENT DIET MAY CAUSE ABNORMAL BRAIN DEVELOPMENT INCLUDING LEARNING AND MEMORY. TO CONFIRM THIS HYPOTHESIS, 3-WEEK-OLD MICE WERE MAINTAINED ON A FOLATE-, METHIONINE- AND CHOLINE-DEFICIENT (FMCD) OR CONTROL (CON) DIET FOR 3 WEEKS. WE FOUND THAT THE METHYL-DONOR DEFICIENCY IMPAIRED BOTH NOVEL OBJECT RECOGNITION AND FEAR EXTINCTION AFTER 3 WEEKS OF TREATMENT. THE FMCD GROUP SHOWED SPONTANEOUS RECOVERY OF FEAR THAT DIFFERED FROM THAT IN CON. IN ADDITION, WE FOUND DECREASED GRIA1 GENE EXPRESSION AND SPECIFIC CPG HYPERMETHYLATION OF THE GRIA1 PROMOTER REGION IN THE FMCD HIPPOCAMPUS. OUR DATA SUGGEST THAT A CHRONIC DIETARY LACK OF METHYL DONORS IN THE DEVELOPMENTAL PERIOD AFFECTS LEARNING, MEMORY AND GENE EXPRESSIONS IN THE HIPPOCAMPUS. 2015 15 1815 25 EFFECTS OF CHRONIC EXPOSURE TO ARSENIC AND ESTROGEN ON EPIGENETIC REGULATORY GENES EXPRESSION AND EPIGENETIC CODE IN HUMAN PROSTATE EPITHELIAL CELLS. CHRONIC EXPOSURES TO ARSENIC AND ESTROGEN ARE KNOWN RISK FACTORS FOR PROSTATE CANCER. THOUGH THE EVIDENCE SUGGESTS THAT EXPOSURE TO ARSENIC OR ESTROGENS CAN DISRUPT NORMAL DNA METHYLATION PATTERNS AND HISTONE MODIFICATIONS, THE MECHANISMS BY WHICH THESE CHEMICALS INDUCE EPIGENETIC CHANGES ARE NOT FULLY UNDERSTOOD. MOREOVER, THE EPIGENETIC EFFECTS OF CO-EXPOSURE TO THESE TWO CHEMICALS ARE NOT KNOWN. THEREFORE, THE OBJECTIVE OF THIS STUDY WAS TO EVALUATE THE EFFECTS OF CHRONIC EXPOSURE TO ARSENIC AND ESTROGEN, BOTH ALONE AND IN COMBINATION, ON THE EXPRESSION OF EPIGENETIC REGULATORY GENES, THEIR CONSEQUENCES ON DNA METHYLATION, AND HISTONE MODIFICATIONS. HUMAN PROSTATE EPITHELIAL CELLS, RWPE-1, CHRONICALLY EXPOSED TO ARSENIC AND ESTROGEN ALONE AND IN COMBINATION WERE USED FOR ANALYSIS OF EPIGENETIC REGULATORY GENES EXPRESSION, GLOBAL DNA METHYLATION CHANGES, AND HISTONE MODIFICATIONS AT PROTEIN LEVEL. THE RESULT OF THIS STUDY REVEALED THAT EXPOSURE TO ARSENIC, ESTROGEN, AND THEIR COMBINATION ALTERS THE EXPRESSION OF EPIGENETIC REGULATORY GENES AND CHANGES GLOBAL DNA METHYLATION AND HISTONE MODIFICATION PATTERNS IN RWPE-1 CELLS. THESE CHANGES WERE SIGNIFICANTLY GREATER IN ARSENIC AND ESTROGEN COMBINATION TREATED GROUP THAN INDIVIDUALLY TREATED GROUP. THE FINDINGS OF THIS STUDY WILL HELP EXPLAIN THE EPIGENETIC MECHANISM OF ARSENIC- AND/OR ESTROGEN-INDUCED PROSTATE CARCINOGENESIS. 2012 16 3981 30 LONG-TERM EPIGENETIC THERAPY WITH ORAL ZEBULARINE HAS MINIMAL SIDE EFFECTS AND PREVENTS INTESTINAL TUMORS IN MICE. RECENT SUCCESSES IN THE APPLICATION OF EPIGENETIC DRUGS FOR THE TREATMENT OF MYELODYSPLASTIC SYNDROME HAVE RAISED QUESTIONS ON THE SAFETY OF LONG-TERM ADMINISTRATION OF DNA METHYLATION INHIBITORS. WE TREATED PREWEANED CANCER PRONE APC(MIN/+) (MIN) MICE CONTINUOUSLY WITH THE DNA METHYLATION INHIBITOR ZEBULARINE IN THEIR DRINKING WATER TO DETERMINE THE EFFECTS OF THE DRUG ON NORMAL MOUSE DEVELOPMENT AS WELL AS CANCER PREVENTION. ZEBULARINE CAUSED A TISSUE-SPECIFIC REDUCTION IN DNA METHYLATION AT B1 SHORT INTERSPERSED NUCLEOTIDE ELEMENTS IN THE SMALL AND LARGE INTESTINES OF FEMALE MIN MICE BUT NOT IN OTHER ORGANS EXAMINED AFTER CHRONIC ORAL TREATMENT. NO SIGNIFICANT DIFFERENCE IN THE AVERAGE WEIGHTS OF MICE WAS OBSERVED DURING THE TREATMENT. IN ADDITION, ANALYSIS OF GLOBAL GENE EXPRESSION OF COLONIC EPITHELIAL CELLS FROM THE FEMALES INDICATED THAT ONLY 3% TO 6% OF THE GENES WERE AFFECTED IN THEIR EXPRESSION. WE DID NOT DETECT TOXICITY AND ABNORMALITIES FROM THE HISTOPATHOLOGIC ANALYSIS OF LIVER AND INTESTINAL TISSUES. LASTLY, WE TESTED WHETHER PREVENTION OF TUMORIGENESIS CAN BE ACHIEVED WITH CHRONIC ORAL ADMINISTRATION OF ZEBULARINE IN MIN MICE. THE AVERAGE NUMBER OF POLYPS IN MIN FEMALES DECREASED FROM 58 TO 1, WHEREAS THE AVERAGE POLYP NUMBER REMAINED UNAFFECTED IN MIN MALES POSSIBLY DUE TO DIFFERENTIAL ACTIVITY OF ALDEHYDE OXIDASE. TAKEN TOGETHER, OUR RESULTS SHOW FOR THE FIRST TIME THAT LONG-TERM ORAL ADMINISTRATION OF ZEBULARINE CAUSES A GENDER-SPECIFIC ABROGATION OF INTESTINAL TUMORS WHILE CAUSING A TISSUE-SPECIFIC DNA DEMETHYLATION. IMPORTANTLY, PROLONGED TREATMENT OF MICE WITH EPIGENETIC DRUGS RESULTED IN ONLY MINOR DEVELOPMENTAL AND HISTOLOGIC CHANGES. 2008 17 3292 33 HIGH FAT DIET AND EXERCISE LEAD TO A DISRUPTED AND PATHOGENIC DNA METHYLOME IN MOUSE LIVER. HIGH-FAT DIET CONSUMPTION AND SEDENTARY LIFESTYLE ELEVATES RISK FOR OBESITY, NON-ALCOHOLIC FATTY LIVER DISEASE, AND CANCER. EXERCISE TRAINING CONVEYS HEALTH BENEFITS IN POPULATIONS WITH OR WITHOUT THESE CHRONIC CONDITIONS. DIET AND EXERCISE REGULATE GENE EXPRESSION BY MEDIATING EPIGENETIC MECHANISMS IN MANY TISSUES; HOWEVER, SUCH EFFECTS ARE POORLY DOCUMENTED IN THE LIVER, A CENTRAL METABOLIC ORGAN. TO DISSECT THE CONSEQUENCES OF DIET AND EXERCISE ON THE LIVER EPIGENOME, WE MEASURED DNA METHYLATION, USING REDUCED REPRESENTATION BISULFITE SEQUENCING, AND TRANSCRIPTION, USING RNA-SEQ, IN MICE MAINTAINED ON A FAST FOOD DIET WITH SEDENTARY LIFESTYLE OR EXERCISE, COMPARED WITH CONTROL DIET WITH AND WITHOUT EXERCISE. OUR ANALYSES REVEAL THAT GENOME-WIDE DIFFERENTIAL DNA METHYLATION AND EXPRESSION OF GENE CLUSTERS ARE INDUCED BY DIET AND/OR EXERCISE. A COMBINATION OF FAST FOOD AND EXERCISE TRIGGERS EXTENSIVE GENE ALTERATIONS, WITH ENRICHMENT OF CARBOHYDRATE/LIPID METABOLIC PATHWAYS AND MUSCLE DEVELOPMENTAL PROCESSES. THROUGH EVALUATION OF PUTATIVE PROTECTIVE EFFECTS OF EXERCISE ON DIET-INDUCED DNA METHYLATION, WE SHOW THAT HYPERMETHYLATION IS EFFECTIVELY PREVENTED, ESPECIALLY AT PROMOTERS AND ENHANCERS, WHEREAS HYPOMETHYLATION IS ONLY PARTIALLY ATTENUATED. WE ASSESSED DIET-INDUCED DNA METHYLATION CHANGES ASSOCIATED WITH LIVER CANCER-RELATED EPIGENETIC MODIFICATIONS AND IDENTIFIED SIGNIFICANT INCREASES AT LIVER-SPECIFIC ENHANCERS IN FAST FOOD GROUPS, SUGGESTING PARTIAL LOSS OF LIVER CELL IDENTITY. HYPERMETHYLATION AT A SUBSET OF GENE PROMOTERS WAS ASSOCIATED WITH INHIBITION OF TISSUE DEVELOPMENT AND PROMOTION OF CARCINOGENIC PROCESSES. OUR STUDY DEMONSTRATES EXTENSIVE REPROGRAMMING OF THE EPIGENOME BY DIET AND EXERCISE, EMPHASIZING THE FUNCTIONAL RELEVANCE OF EPIGENETIC MECHANISMS AS AN INTERFACE BETWEEN LIFESTYLE MODIFICATIONS AND PHENOTYPIC ALTERATIONS. 2017 18 2747 36 EXPRESSION ANALYSIS OF THE EPIGENETIC METHYLTRANSFERASES AND METHYL-CPG BINDING PROTEIN FAMILIES IN THE NORMAL B-CELL AND B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). THE IMPORTANCE OF EPIGENETIC MODIFICATIONS IN CARCINOGENESIS HAS BEEN A SOURCE OF CONTROVERSY FOR SOME TIME. THERE IS LITTLE DOUBT THAT CHANGES IN GENOMIC HYPERMETHYLATION CONTRIBUTE TO THE SILENCING OF TUMOR SUPPRESSOR GENES. FURTHERMORE, RECENT STUDIES HAVE ALSO IDENTIFIED THE SIGNIFICANCE OF GENOMIC HYPOMETHYLATION ASSOCIATED WITH CHROMOSOMAL INSTABILITY AND TUMORIGENESIS. ONE OF THE MOST PERPLEXING QUESTIONS REGARDING EPIGENETIC MODIFICATIONS AND LEUKEMOGENESIS IS THE RELATIONSHIP WITH DNA METHYLTRANSFERASES (DNMT'S). THE PRIMARY FUNCTION OF THE DNMT ENZYMES IS TO METHYLATE GENOMIC DNA, WHEREAS THE METHYL-CPG BINDING DOMAIN PROTEINS (MBD) INTERPRET THIS METHYLATION SIGNAL AND REGULATE GENE EXPRESSION AND CHROMATIN BEHAVIOR. IN THIS STUDY WE ANALYSE THESE GENE FAMILIES BY QUANTITATIVE REAL-TIME PCR TO INVESTIGATE WHETHER EXPRESSION LEVELS AND THE B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (B-CLL) PHENOTYPE ARE ASSOCIATED. FURTHERMORE, GIVEN THE EPIGENETIC CROSSTALK BETWEEN GENOME STABILITY AND THE HISTONE CHROMATIN CODE WE HAVE ANALYSED EUKARYOTIC HISTONE METHYLTRANSFERASE (EU-HMTASEI). SURPRISINGLY, WE DID NOT OBSERVE SIGNIFICANT CHANGES IN DNMT1 EXPRESSION IN B-CLL CASES WHEN COMPARED TO NORMAL LYMPHOCYTES, REGARDLESS OF WHETHER WE NORMALISE AGAINST GAPDH OR PCNA AS REFERENCE STANDARDS. INDEED, EXPRESSION OF THE MAINTENANCE AND DE NOVO METHYLASES WERE INDEPENDENTLY REGULATED. OF PARTICULAR NOTE WAS THE SIGNIFICANT DOWN REGULATION OF DNMT3B. FURTHERMORE, WE OBSERVED A POSITIVE CORRELATION BETWEEN HMTASEI EXPRESSION LEVELS AND STAGE OF LEUKEMIA SUGGESTING THAT CHANGES IN THE METHYLATION PATTERNS IN B-CLL MAY REPRESENT DEREGULATION OF THE EPIGENETIC REPERTOIRE THAT ALSO INCLUDE THE METHYLATION DEPENDENT BINDING PROTEINS, MBD2 AND MECP2. WE ENVISAGE CHANGES IN THE EPIGENETIC PROGRAM ARE MULTIFACTORIAL IN NATURE AND POSTULATE THAT THE PREVALENT GENOMIC METHYLASES JUST ONE COMPONENT OF A LARGER EPIGENETIC REPERTOIRE. 2004 19 904 29 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 20 2158 40 EPIGENETIC MECHANISMS FOR NUTRITION DETERMINANTS OF LATER HEALTH OUTCOMES. EPIGENETIC MARKING ON GENES CAN DETERMINE WHETHER OR NOT GENES ARE EXPRESSED. EPIGENETIC REGULATION IS MEDIATED BY THE ADDITION OF METHYL GROUPS TO DNA CYTOSINE BASES, OF METHYL AND ACETYL GROUPS TO PROTEINS (HISTONES) AROUND WHICH DNA IS WRAPPED, AND BY SMALL INTERFERING RNA MOLECULES. SOME COMPONENTS OF EPIGENETIC REGULATION HAVE EVOLVED TO PERMIT CONTROL OF WHETHER MATERNAL OR PATERNAL GENES ARE EXPRESSED. THE EPIGENETIC IMPRINTING OF IGF2 EXPRESSION IS AN EXAMPLE OF MATERNAL AND PATERNAL EPIGENETIC MARKING THAT MODULATES FETAL GROWTH AND FETAL SIZE. HOWEVER, EPIGENETIC REGULATION ALSO PERMITS THE FETUS AND THE INFANT TO ADAPT GENE EXPRESSION TO THE ENVIRONMENT IN WHICH IT IS GROWING; SOMETIMES WHEN THIS ADJUSTMENT GOES AWRY, THE RISK OF CHRONIC DISEASE IS INCREASED. RECENT PROGRESS IN THE UNDERSTANDING OF NUTRITIONAL INFLUENCES ON EPIGENETICS SUGGESTS THAT NUTRIENTS THAT ARE PART OF METHYL-GROUP METABOLISM CAN SIGNIFICANTLY INFLUENCE EPIGENETICS. DURING CRITICAL PERIODS IN DEVELOPMENT, DIETARY METHYL-GROUP INTAKE (CHOLINE, METHIONINE, AND FOLATE) CAN ALTER DNA AND HISTONE METHYLATION, WHICH RESULTS IN LIFELONG CHANGES IN GENE EXPRESSION. IN RODENT MODELS, PREGNANT DAMS THAT WERE FED DIETS HIGH IN METHIONINE, FOLIC ACID, AND CHOLINE PRODUCED OFFSPRING WITH DIFFERENT COAT COLORS OR WITH KINKED TAILS. A NUMBER OF SYNDROMES IN HUMANS CAN BE CAUSED BY DEFECTIVE EPIGENETIC REGULATION, INCLUDING RETT SYNDROME. THERE ARE INTERESTING EXAMPLES OF THE EFFECTS OF NUTRITION IN EARLY LIFE THAT RESULT IN ALTERED HEALTH IN ADULTS, AND SOME OF THESE COULD BE THE RESULT OF ALTERED EPIGENETIC REGULATION OF GENE EXPRESSION. 2009