1 122 116 A SYSTEMATIC REVIEW ON FLUORIDE-INDUCED EPIGENETIC TOXICITY IN MAMMALS. FLUORIDE, ONE OF THE GLOBAL GROUNDWATER CONTAMINANTS, IS UBIQUITOUS IN OUR DAY-TO-DAY LIFE FROM VARIOUS NATURAL AND ANTHROPOGENIC SOURCES. NUMEROUS IN VITRO, IN VIVO, AND EPIDEMIOLOGICAL STUDIES ARE CONDUCTED TO UNDERSTAND THE EFFECT OF FLUORIDE ON BIOLOGICAL SYSTEMS. A LOW CONCENTRATION OF FLUORIDE IS REPORTED TO INCREASE ORAL HEALTH, WHEREAS CHRONIC EXPOSURE TO HIGHER CONCENTRATIONS CAUSES FLUORIDE TOXICITY (FLUOROSIS). IT INCLUDES DENTAL FLUOROSIS, SKELETAL FLUOROSIS, AND FLUORIDE TOXICITY IN SOFT TISSUES. THE MECHANISM OF FLUORIDE TOXICITY HAS BEEN REVIEWED EXTENSIVELY. HOWEVER, EPIGENETIC REGULATION IN FLUORIDE TOXICITY HAS NOT BEEN REVIEWED. THIS SYSTEMATIC REVIEW SUMMARIZES THE CURRENT KNOWLEDGE REGARDING FLUORIDE-INDUCED EPIGENETIC TOXICITY IN THE IN VITRO, IN VIVO, AND EPIDEMIOLOGICAL STUDIES IN MAMMALIAN SYSTEMS. WE EXAMINED FOUR DATABASES FOR THE ASSOCIATION BETWEEN EPIGENETICS AND FLUORIDE EXPOSURE. OUT OF 932 ARTICLES (AS OF 31 MARCH 2022), 39 MET OUR INCLUSION CRITERIA. MOST OF THE STUDIES FOCUSED ON DIFFERENT GENES, AND OVERALL, PRELIMINARY EVIDENCE FOR EPIGENETIC REGULATION OF FLUORIDE TOXICITY WAS IDENTIFIED. WE FURTHER HIGHLIGHT THE NEED FOR EPIGENOME STUDIES RATHER THAN CANDIDATE GENES AND PROVIDE RECOMMENDATIONS FOR FUTURE RESEARCH. OUR RESULTS INDICATE A CORRELATION BETWEEN FLUORIDE EXPOSURE AND EPIGENETIC PROCESSES. FURTHER STUDIES ARE WARRANTED TO ELUCIDATE AND CONFIRM THE MECHANISM OF EPIGENETIC ALTERATIONS MEDIATED FLUORIDE TOXICITY. 2022 2 5555 27 ROLE OF FLUORIDE INDUCED EPIGENETIC ALTERATIONS IN THE DEVELOPMENT OF SKELETAL FLUOROSIS. FLUORIDE IS AN ESSENTIAL TRACE ELEMENT REQUIRED FOR PROPER BONE AND TOOTH DEVELOPMENT. SYSTEMIC HIGH EXPOSURE TO FLUORIDE THROUGH ENVIRONMENTAL EXPOSURE (DRINKING WATER AND FOOD) MAY RESULT IN TOXICITY CAUSING A DISORDER CALLED FLUOROSIS. IN THE PRESENT STUDY, WE INVESTIGATED THE ALTERATION IN DNA METHYLATION PROFILE WITH CHRONIC EXPOSURE (30 DAYS) TO FLUORIDE (8 MG/L) AND ITS RELEVANCE IN THE DEVELOPMENT OF FLUOROSIS. WHOLE GENOME BISULFITE SEQUENCING (WGBS) WAS CARRIED OUT IN HUMAN OSTEOSARCOMA CELLS (HOS) EXPOSED TO FLUORIDE. WHOLE GENOME BISULFITE SEQUENCING (WGBS) AND FUNCTIONAL ANNOTATION OF DIFFERENTIALLY METHYLATED GENES INDICATE ALTERATIONS IN METHYLATION STATUS OF GENES INVOLVED IN BIOLOGICAL PROCESSES ASSOCIATED WITH BONE DEVELOPMENT PATHWAYS. COMBINED ANALYSIS OF PROMOTER DNA HYPER METHYLATION, STRING: FUNCTIONAL PROTEIN ASSOCIATION NETWORKS AND GENE EXPRESSION ANALYSIS REVEALED EPIGENETIC ALTERATIONS IN BMP1, METAP2, MMP11 AND BACH1 GENES, WHICH PLAYS A ROLE IN THE EXTRACELLULAR MATRIX DISASSEMBLY, COLLAGEN CATABOLIC/ORGANIZATION PROCESS, SKELETAL MORPHOGENESIS/DEVELOPMENT, OSSIFICATION AND OSTEOBLAST DEVELOPMENT. THE PRESENT STUDY SHOWS THAT FLUORIDE CAUSES PROMOTER DNA HYPERMETHYLATION IN BMP1, METAP2, MMP11 AND BACH1 GENES WITH SUBSEQUENT DOWN-REGULATION IN THEIR EXPRESSION LEVEL (RNA LEVEL). THE RESULTS IMPLIES THAT FLUORIDE INDUCED DNA HYPERMETHYLATION OF THESE GENES MAY HAMPER EXTRACELLULAR MATRIX DEPOSITION, CARTILAGE FORMATION, ANGIOGENESIS, VASCULAR SYSTEM DEVELOPMENT AND POROSITY OF BONE, THUS PROMOTE SKELETAL FLUOROSIS. 2019 3 907 23 CHRONIC EXPOSURE TO ENVIRONMENTALLY RELEVANT CONCENTRATION OF FLUORIDE ALTERS OGG1 AND RAD51 EXPRESSIONS IN MICE: INVOLVEMENT OF EPIGENETIC REGULATION. CHRONIC EXPOSURE TO FLUORIDE (F) BEYOND THE PERMISSIBLE LIMIT (1.5 PPM) IS KNOWN TO CAUSE DETRIMENTAL HEALTH EFFECTS BY INDUCTION OF OXIDATIVE STRESS-MEDIATED DNA DAMAGE OVERPOWERING THE DNA REPAIR MACHINERY. IN THE PRESENT STUDY, WE ASSESSED F INDUCED OXIDATIVE STRESS THROUGH MONITORING BIOCHEMICAL PARAMETERS AND LOOKED INTO THE EFFECT OF CHRONIC F EXPOSURE ON TWO CRUCIAL DNA REPAIR GENES OGG1 AND RAD51 HAVING IMPORTANT ROLE AGAINST ROS INDUCED DNA DAMAGES. TO ADDRESS THIS ISSUE, WE EXPOSED SWISS ALBINO MICE TO AN ENVIRONMENTALLY RELEVANT CONCENTRATION OF FLUORIDE (15 PPM NAF) FOR 8 MONTHS. RESULTS REVEALED HISTOARCHITECTURAL DAMAGES IN LIVER, BRAIN, KIDNEY AND SPLEEN. DEPLETION OF GSH, INCREASE IN LIPID PEROXIDATION AND CATALASE ACTIVITY IN LIVER AND BRAIN CONFIRMED THE GENERATION OF OXIDATIVE STRESS. QRT-PCR RESULT SHOWED THAT EXPRESSIONS OF OGG1 AND RAD51 WERE ALTERED AFTER F EXPOSURE IN THE AFFECTED ORGANS. PROMOTER HYPERMETHYLATION WAS ASSOCIATED WITH THE DOWNREGULATION OF RAD51. F-INDUCED DNA DAMAGE AND THE COMPROMISED DNA REPAIR MACHINERY TRIGGERED INTRINSIC PATHWAY OF APOPTOSIS IN LIVER AND BRAIN. THE PRESENT STUDY INDICATES THE POSSIBLE ASSOCIATION OF EPIGENETIC REGULATION WITH F INDUCED NEUROTOXICITY. 2020 4 5194 37 PRENATAL EXPOSURE TO POTENTIALLY TOXIC METALS AND THEIR EFFECTS ON GENETIC MATERIAL IN OFFSPRING: A SYSTEMATIC REVIEW. IN RECENT YEARS, THE BACKGROUND LEVEL OF ENVIRONMENTAL POLLUTANTS, INCLUDING METALS, HAS INCREASED. POLLUTANT EXPOSURE DURING THE EARLIEST STAGES OF LIFE MAY DETERMINE CHRONIC DISEASE SUSCEPTIBILITY IN ADULTHOOD BECAUSE OF GENETIC OR EPIGENETIC CHANGES. THE OBJECTIVE OF THIS REVIEW WAS TO IDENTIFY THE ASSOCIATION BETWEEN PRENATAL AND EARLY POSTNATAL EXPOSURE TO POTENTIALLY TOXIC METALS (PTMS) AND THEIR ADVERSE EFFECTS ON THE GENETIC MATERIAL OF OFFSPRING. A SYSTEMATIC REVIEW WAS CARRIED OUT FOLLOWING THE COCHRANE METHODOLOGY IN FOUR DATABASES: PUBMED, SCOPUS, WEB OF SCIENCE, AND THE COCHRANE LIBRARY. ELIGIBLE PAPERS WERE THOSE CONDUCTED IN HUMANS AND PUBLISHED IN ENGLISH BETWEEN 2010/01/01 AND 2021/04/30. A TOTAL OF 57 ARTICLES WERE INCLUDED, MOST OF WHICH EVALUATED PRENATAL EXPOSURE. MOST COMMONLY EVALUATED PTMS WERE AS, CD, AND PB. MAIN ADVERSE EFFECTS ON THE GENETIC MATERIAL OF NEWBORNS ASSOCIATED WITH PTM PRENATAL EXPOSURE WERE ALTERATIONS IN TELOMERE LENGTH, GENE OR PROTEIN EXPRESSION, MITOCHONDRIAL DNA CONTENT, METABOLOMICS, DNA DAMAGE, AND EPIGENETIC MODIFICATIONS. MANY OF THESE EFFECTS WERE SEX-SPECIFIC, BEING PREDOMINANT IN BOYS. ONE ARTICLE REPORTED A SYNERGISTIC INTERACTION BETWEEN AS AND HG, AND TWO ARTICLES OBSERVED ANTAGONISTIC INTERACTIONS BETWEEN PTMS AND ESSENTIAL METALS, SUCH AS CU, SE, AND ZN. THE FINDINGS IN THIS REVIEW HIGHLIGHT THAT THE PROBLEM OF PTM EXPOSURE PERSISTS, AFFECTING THE MOST SUSCEPTIBLE POPULATIONS, SUCH AS NEWBORNS. SOME OF THESE ASSOCIATIONS WERE OBSERVED AT LOW CONCENTRATIONS OF PTMS. MOST OF THE STUDIES HAVE FOCUSED ON SINGLE EXPOSURES; HOWEVER, THREE INTERACTIONS BETWEEN ESSENTIAL AND NONESSENTIAL METALS WERE OBSERVED, HIGHLIGHTING THAT METAL MIXTURES NEED MORE ATTENTION. 2023 5 6790 24 [DNA METHYLATION ANALYSIS IN ENVIRONMENTAL AND OCCUPATIONAL CANCER RESEARCH]. THE PRESENT PAPER REVIEWS RECENT LABORATORY METHODS AND EXPERIMENTAL EVIDENCE CONCERNING EPIGENETIC BIOMARKERS INVOLVED IN CARCINOGENESIS MECHANISMS. WE INTRODUCE DNA METHYLATION AND ITS ROLE IN GENE EXPRESSION CONTROL. DNA METHYLATION ANALYSIS MAY ALLOW TO IDENTIFY EARLY CHANGES LEADING TO CANCER AND OTHER CHRONIC DISEASES. WE DESCRIBE HERE STRATEGIES FOR LABORATORY ANALYSES AND THEIR POSSIBLE APPLICATIONS. WE EXAMINE RESULTS FROM RECENT EXPERIMENTAL STUDIES SUGGESTING THAT THE EFFECTS OF CERTAIN OCCUPATIONAL AGENTS ARE MEDIATED BY ALTERATIONS IN DNA METHYLATION. PLANNING AND CONDUCTING INVESTIGATIONS ON EXPOSED HUMAN SUBJECTS WILL ALLOW TO VERIFY WHETHER DNA METHYLATION CHANGES IDENTIFIED IN ANIMAL AND IN-VITRO STUDIES MAY BE USED AS EARLY-EFFECT AND SUSCEPTIBILITY BIOMARKERS. DNA METHYLATION ANALYSIS HAS THE POTENTIAL FOR FUTURE APPLICATIONS IN RISK ASSESSMENT AND PREVENTION PROGRAMS CONDUCTED ON SUBJECTS EXPOSED TO HUMAN CARCINOGENS. 2005 6 588 35 BENZENE EXPOSURE IS ASSOCIATED WITH EPIGENETIC CHANGES (REVIEW). BENZENE IS A VOLATILE AROMATIC HYDROCARBON SOLVENT AND IS KNOWN AS ONE OF THE PREDOMINANT AIR POLLUTANTS IN THE ENVIRONMENT. CHRONIC EXPOSURE TO BENZENE IS KNOWN TO CAUSE APLASTIC ANEMIA AND INCREASED RISK OF ACUTE MYELOGENOUS LEUKEMIA IN HUMANS. ALTHOUGH THE MECHANISMS BY WHICH BENZENE CAUSES TOXICITY REMAIN TO BE FULLY ELUCIDATED, IT IS WIDELY ACCEPTED THAT ITS METABOLISM IS CRUCIAL TO ITS TOXICITY, WITH INVOLVEMENT OF ONE OR MORE REACTIVE METABOLITES. NOVEL APPROACHES AIMED AT EVALUATING DIFFERENT MECHANISMS BY WHICH BENZENE CAN IMPACT ON HUMAN HEALTH BY ALTERING GENE REGULATION HAVE BEEN DEVELOPED. AMONG THESE NOVEL APPROACHES, EPIGENETICS APPEARS TO BE PROMISING. THE PRESENT REVIEW ARTICLE SUMMARIZES THE MOST IMPORTANT FINDINGS, REPORTED FROM THE LITERATURE, ON EPIGENETIC MODIFICATIONS CORRELATED TO BENZENE EXPOSURE. A COMPUTERIZED SEARCH IN PUBMED WAS PERFORMED IN NOVEMBER 2014, USING SEARCH TERMS, INCLUDING 'BENZENE', 'EPIGENETIC', 'HISTONE MODIFICATIONS', 'DNA METHYLATION' AND 'MICRORNA'. EPIDEMIOLOGICAL AND EXPERIMENTAL STUDIES HAVE DEMONSTRATED THE POTENTIAL EPIGENETIC EFFECTS OF BENZENE EXPOSURE. SEVERAL OF THE EPIGENOMIC CHANGES OBSERVED IN RESPONSE TO ENVIRONMENTAL EXPOSURES MAY BE MECHANISTICALLY ASSOCIATED WITH SUSCEPTIBILITY TO DISEASES. HOWEVER, FURTHER ELUCIDATION OF THE MECHANISMS BY WHICH BENZENE ALTERS GENE EXPRESSION MAY IMPROVE PREDICTION OF THE TOXIC POTENTIAL OF NOVEL COMPOUNDS INTRODUCED INTO THE ENVIRONMENT, AND ALLOW FOR MORE TARGETED AND APPROPRIATE DISEASE PREVENTION STRATEGIES. 2016 7 457 33 APPLYING A MULTISCALE SYSTEMS BIOLOGY APPROACH TO STUDY THE EFFECT OF CHRONIC LOW-DOSE EXPOSURE TO URANIUM IN RAT KIDNEYS. PURPOSE: TO EXAMINE THE EFFECTS OF LOW-DOSE EXPOSURE TO URANIUM WITH A SYSTEMS BIOLOGY APPROACH, A MULTISCALE HIGH-THROUGHPUT MULTI-OMICS ANALYSIS WAS APPLIED WITH A PROTOCOL FOR CHRONIC EXPOSURE TO THE RAT KIDNEY. METHODS: MALE AND FEMALE RATS WERE CONTAMINATED FOR NINE MONTHS THROUGH THEIR DRINKING WATER WITH A NONTOXIC SOLUTION OF URANYL NITRATE. A MULTISCALE APPROACH ENABLED CLINICAL MONITORING ASSOCIATED WITH METABOLOMIC AND TRANSCRIPTOMIC (MRNA AND MICRORNA) ANALYSES. RESULTS: A SEX-INTERACTION EFFECT WAS OBSERVED IN THE KIDNEY, URINE, AND PLASMA METABOLOMES OF CONTAMINATED RATS. MOREOVER, URINE AND KIDNEY METABOLIC PROFILES CORRELATED AND CONFIRMED THAT THE PRIMARY DYSREGULATED METABOLISMS ARE THOSE OF NICOTINATE-NICOTINAMIDE AND OF UNSATURATED FATTY ACID BIOSYNTHESIS. UPSTREAM OF THE METABOLIC PATHWAYS, TRANSCRIPTOMIC PROFILES OF THE KIDNEY REVEAL GENE ACTIVITY FOCUSED ON GENE REGULATION MECHANISMS, CELL SIGNALING, CELL STRUCTURE, DEVELOPMENTAL PROCESSES, AND CELL PROLIFERATION. EXAMINATION OF EPIGENETIC POST-TRANSCRIPTIONAL GENE REGULATION PROCESSES SHOWED SIGNIFICANT DYSREGULATION OF 70 MICRO-RNAS. THE MULTI-OMICS APPROACH HIGHLIGHTED THE ACTIVITIES OF THE CELLS' BIOLOGICAL PROCESSES ON MULTIPLE SCALES THROUGH ANALYSIS OF GENE EXPRESSION, CONFIRMED BY CHANGES OBSERVED IN THE METABOLOME. CONCLUSION: OUR RESULTS SHOWED CHANGES IN MULTI-OMIC PROFILES OF RATS EXPOSED TO LOW DOSES OF URANIUM CONTAMINATION, COMPARED WITH CONTROLS. THESE CHANGES INVOLVED GENE EXPRESSION AS WELL AS MODIFICATIONS IN THE TRANSCRIPTOME AND THE METABOLOME. THE METABOLOMIC PROFILE CONFIRMED THAT THE MAIN MOLECULAR TARGETS OF URANIUM IN KIDNEY CELLS ARE THE METABOLISM OF NICOTINATE-NICOTINAMIDE AND THE BIOSYNTHESIS OF UNSATURATED FATTY ACIDS. ADDITIONALLY, GENE EXPRESSION ANALYSIS SHOWED THAT THE METABOLISM OF FATTY ACIDS IS TARGETED BY PROCESSES ASSOCIATED WITH CELL FUNCTION. THESE RESULTS DEMONSTRATE THAT MULTISCALE SYSTEMS BIOLOGY IS USEFUL IN ELUCIDATING THE MOST DISCRIMINATIVE PATHWAYS FROM GENOMIC TO METABOLOMIC LEVELS FOR ASSESSING THE BIOLOGICAL IMPACT OF THIS LOW-LEVEL ENVIRONMENTAL EXPOSURE, I.E. THE EXPOSOME. 2019 8 904 34 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 9 3042 26 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 10 228 39 ADAPTATION OF THE HUMAN POPULATION TO THE ENVIRONMENT: CURRENT KNOWLEDGE, CLUES FROM CZECH CYTOGENETIC AND "OMICS" BIOMONITORING STUDIES AND POSSIBLE MECHANISMS. THE HUMAN POPULATION IS CONTINUALLY EXPOSED TO NUMEROUS HARMFUL ENVIRONMENTAL STRESSORS, CAUSING NEGATIVE HEALTH EFFECTS AND/OR DEREGULATION OF BIOMARKER LEVELS. HOWEVER, STUDIES REPORTING NO OR EVEN POSITIVE IMPACTS OF SOME STRESSORS ON HUMANS ARE ALSO SOMETIMES PUBLISHED. THE MAIN AIM OF THIS REVIEW IS TO PROVIDE A COMPREHENSIVE OVERVIEW OF THE LAST DECADE OF CZECH BIOMONITORING RESEARCH, CONCERNING THE EFFECT OF VARIOUS LEVELS OF AIR POLLUTION (BENZO[A]PYRENE) AND RADIATION (URANIUM, X-RAY EXAMINATION AND NATURAL RADON BACKGROUND), ON THE DIFFERENTLY EXPOSED POPULATION GROUPS. BECAUSE SOME RESULTS OBTAINED FROM CYTOGENETIC STUDIES WERE OPPOSITE THAN HYPOTHESIZED, WE HAVE SEARCHED FOR A MEANINGFUL INTERPRETATION IN GENOMIC/EPIGENETIC STUDIES. A DETAILED ANALYSIS OF OUR DATA SUPPORTED BY THE STUDIES OF OTHERS AND CURRENT EPIGENETIC KNOWLEDGE, LEADS TO A HYPOTHESIS OF THE VERSATILE MECHANISM OF ADAPTATION TO ENVIRONMENTAL STRESSORS VIA DNA METHYLATION SETTINGS WHICH MAY EVEN ORIGINATE IN PRENATAL DEVELOPMENT, AND HELP TO REDUCE THE RESULTING DNA DAMAGE LEVELS. THIS HYPOTHESIS IS FULLY IN AGREEMENT WITH UNEXPECTED DATA FROM OUR STUDIES (E.G. LOWER LEVELS OF DNA DAMAGE IN SUBJECTS FROM HIGHLY POLLUTED REGIONS THAN IN CONTROLS OR IN SUBJECTS EXPOSED REPEATEDLY TO A POLLUTANT THAN IN THOSE WITHOUT PREVIOUS EXPOSURE), AND IS ALSO SUPPORTED BY DIFFERENCES IN DNA METHYLATION PATTERNS IN GROUPS FROM REGIONS WITH VARIOUS LEVELS OF POLLUTION. IN LIGHT OF THE ADAPTATION HYPOTHESIS, THE FOLLOWING POINTS MAY BE SUGGESTED FOR FUTURE RESEARCH: (I) THE CHRONIC AND ACUTE EXPOSURE OF STUDY SUBJECTS SHOULD BE DISTINGUISHED; (II) THE EXPOSURE HISTORY SHOULD BE MAPPED INCLUDING PLACE OF RESIDENCE DURING THE LIFE AND PRENATAL DEVELOPMENT; (III) CHANGES OF EPIGENETIC MARKERS SHOULD BE MONITORED OVER TIME. IN SUMMARY, INVESTIGATION OF HUMAN ADAPTATION TO THE ENVIRONMENT, ONE OF THE MOST IMPORTANT PROCESSES OF SURVIVAL, IS A NEW CHALLENGE FOR FUTURE RESEARCH IN THE FIELD OF HUMAN BIOMONITORING THAT MAY CHANGE OUR VIEW ON THE RESULTS OF BIOMARKER ANALYSES AND POTENTIAL NEGATIVE HEALTH IMPACTS OF THE ENVIRONMENT. 2017 11 1324 37 DEOXYRIBONUCLEIC ACID (DNA) METHYLATION IN CHILDREN EXPOSED TO AIR POLLUTION: A POSSIBLE MECHANISM UNDERLYING RESPIRATORY HEALTH EFFECTS DEVELOPMENT. AIR POLLUTION IS A SUBSTANTIAL ENVIRONMENTAL THREAT TO CHILDREN AND ACTS AS ACUTE AND CHRONIC DISEASE RISK FACTORS ALIKE. SEVERAL STUDIES HAVE PREVIOUSLY EVALUATED EPIGENETIC MODIFICATIONS CONCERNING ITS EXPOSURE ACROSS VARIOUS LIFE STAGES. HOWEVER, FINDINGS ON EPIGENETIC MODIFICATIONS AS THE CONSEQUENCES OF AIR POLLUTION DURING CHILDHOOD ARE RATHER MINIMAL. THIS REVIEW EVALUATED HIGHLY RELEVANT STUDIES IN THE FIELD TO ANALYZE THE EXISTING LITERATURE REGARDING EXPOSURE TO AIR POLLUTION, WITH A FOCUS ON EPIGENETIC ALTERATIONS DURING CHILDHOOD AND THEIR CONNECTIONS WITH RESPIRATORY HEALTH EFFECTS. THE SEARCH WAS CONDUCTED USING READILY AVAILABLE ELECTRONIC DATABASES (PUBMED AND SCIENCEDIRECT) TO SCREEN FOR CHILDREN'S STUDIES ON EPIGENETIC MECHANISMS FOLLOWING EITHER PRE- OR POST-NATAL EXPOSURE TO AIR POLLUTANTS. STUDIES RELEVANT ENOUGH AND MATCHED THE PREDETERMINED CRITERIA WERE CHOSEN TO BE REVIEWED. NON-ENGLISH ARTICLES AND STUDIES THAT DID NOT REPORT BOTH AIR MONITORING AND EPIGENETIC OUTCOMES IN THE SAME ARTICLE WERE EXCLUDED. THE REVIEW FOUND THAT EPIGENETIC CHANGES HAVE BEEN LINKED WITH EXPOSURE TO AIR POLLUTANTS DURING EARLY LIFE WITH EVIDENCE AND REPORTS OF HOW THEY MAY DEREGULATE THE EPIGENOME BALANCE, THUS INDUCING DISEASE PROGRESSION IN THE FUTURE. EPIGENETIC STUDIES EVOLVE AS A PROMISING NEW APPROACH IN DECIPHERING THE UNDERLYING IMPACTS OF AIR POLLUTION ON DEOXYRIBONUCLEIC ACID (DNA) DUE TO LINKS ESTABLISHED BETWEEN SOME OF THESE EPIGENETIC MECHANISMS AND ILLNESSES. 2021 12 2507 28 EPIGENETICS AND OBESITY: THE DEVIL IS IN THE DETAILS. OBESITY IS A COMPLEX DISEASE WITH MULTIPLE WELL-DEFINED RISK FACTORS. NEVERTHELESS, SUSCEPTIBILITY TO OBESITY AND ITS SEQUELAE WITHIN OBESOGENIC ENVIRONMENTS VARIES GREATLY FROM ONE PERSON TO THE NEXT, SUGGESTING A ROLE FOR GENE X ENVIRONMENT INTERACTIONS IN THE ETIOLOGY OF THE DISORDER. EPIGENETIC REGULATION OF THE HUMAN GENOME PROVIDES A PUTATIVE MECHANISM BY WHICH SPECIFIC ENVIRONMENTAL EXPOSURES CONVEY RISK FOR OBESITY AND OTHER HUMAN DISEASES AND IS ONE POSSIBLE MECHANISM THAT UNDERLIES THE GENE X ENVIRONMENT/TREATMENT INTERACTIONS OBSERVED IN EPIDEMIOLOGICAL STUDIES AND CLINICAL TRIALS. A STUDY PUBLISHED IN BMC MEDICINE THIS MONTH BY WANG ET AL. REPORTS ON AN EXAMINATION OF DNA METHYLATION IN PERIPHERAL BLOOD LEUKOCYTES OF LEAN AND OBESE ADOLESCENTS, COMPARING METHYLATION PATTERNS BETWEEN THE TWO GROUPS. THE AUTHORS IDENTIFIED TWO GENES THAT WERE DIFFERENTIALLY METHYLATED, BOTH OF WHICH HAVE ROLES IN IMMUNE FUNCTION. HERE WE OVERVIEW THE FINDINGS FROM THIS STUDY IN THE CONTEXT OF THOSE EMERGING FROM OTHER RECENT GENETIC AND EPIGENETIC STUDIES, DISCUSS THE STRENGTHS AND WEAKNESSES OF THE STUDY AND SPECULATE ON THE FUTURE OF EPIGENETICS IN CHRONIC DISEASE RESEARCH. 2010 13 1811 33 EFFECTS OF ARSENIC TOXICITY BEYOND EPIGENETIC MODIFICATIONS. WORLDWIDE CHRONIC ARSENIC (AS) POISONING BY ARSENIC-CONTAMINATED GROUNDWATER IS ONE OF THE MOST THREATENING PUBLIC HEALTH PROBLEMS. CHRONIC INORGANIC AS (INAS) EXPOSURE HAS BEEN ASSOCIATED WITH VARIOUS FORMS OF CANCERS AND NUMEROUS OTHER PATHOLOGICAL EFFECTS IN HUMANS, COLLECTIVELY KNOWN AS ARSENICOSIS. OVER THE PAST DECADE, EVIDENCE INDICATED THAT AS-INDUCED EPIGENETIC MODIFICATIONS HAVE A ROLE IN THE ADVERSE EFFECTS ON HUMAN HEALTH. THE MAIN OBJECTIVE OF THIS ARTICLE IS TO REVIEW THE EVIDENCE ON EPIGENETIC MODIFICATIONS INDUCED BY ARSENICALS. THE EPIGENETIC COMPONENTS PLAY A CRUCIAL ROLE IN THE REGULATION OF GENE EXPRESSION, AT BOTH TRANSCRIPTIONAL AND POSTTRANSCRIPTIONAL LEVELS. WE SYNTHESIZED THE LARGE BODY OF EXISTING RESEARCH ON ARSENIC EXPOSURE AND EPIGENETIC MECHANISMS OF HEALTH OUTCOMES WITH AN EMPHASIS ON RECENT PUBLICATIONS. CHANGES IN PATTERNS OF DNA METHYLATION, HISTONE POSTTRANSLATIONAL MODIFICATIONS, AND MICRORNAS HAVE BEEN REPEATEDLY OBSERVED AFTER INAS EXPOSURE IN LABORATORY STUDIES AND IN STUDIES OF HUMAN POPULATIONS. SUCH ALTERATIONS HAVE THE POTENTIAL TO DISTURB CELLULAR HOMEOSTASIS, RESULTING IN THE MODULATION OF KEY PATHWAYS IN THE AS-INDUCED CARCINOGENESIS. THE PRESENT ARTICLE REVIEWS RECENT DATA ON AS-INDUCED EPIGENETIC EFFECTS AND CONCLUDES THAT IT IS TIME FOR HEIGHTENED AWARENESS OF PATHOGENIC ARSENIC EXPOSURE, PARTICULARLY FOR PREGNANT WOMEN AND CHILDREN, GIVEN THE POTENTIAL FOR A LONG-LASTING DISTURBED CELLULAR HOMEOSTASIS. 2018 14 6313 38 THE RELATIONSHIP BETWEEN MERCURY EXPOSURE AND EPIGENETIC ALTERATIONS REGARDING HUMAN HEALTH, RISK ASSESSMENT AND DIAGNOSTIC STRATEGIES. BACKGROUND: EXPOSURE TO THE ENVIRONMENTAL TOXICANTS POSES A SERIOUS THREAT TO HUMAN HEALTH. THE EXTENT OF EXPOSURE AND THE DEVELOPMENT OF DISEASES ARE INTERRELATED WITH EACH OTHER. CHRONIC EXPOSURE TO MERCURY (HG) INCREASES THE RISK OF DEVELOPING SERIOUS HUMAN DISORDERS FROM EMBRYO TO ADULTHOOD. OBJECTIVES: THE PURPOSE OF THIS REVIEW IS TO HIGHLIGHT THE MOST COMMON HUMAN DISORDERS INDUCED BY HG EXPOSURE ON THE BASIS OF EPIGENETIC MECHANISMS. A GROWING BODY OF EVIDENCE SHOWS THAT HG EXPOSURE LEADS TO ALTERATIONS IN THE EPIGENETIC MARKERS. METHODS: WE PERFORMED AN ORGANIZED SEARCH OF THE AVAILABLE LITERATURE USING PUBMED, GOOGLE SCHOLAR, MEDLINE, REAXYS, EMBASE AND SCOPUS DATABASES. ALL THE RELEVANT CITATIONS, INCLUDING RESEARCH AND REVIEW ARTICLES IN ENGLISH WERE EVALUATED. THE SEARCH TERMS INCLUDED MERCURY, HG, EPIGENETICS, EPIGENETIC ALTERATIONS, DNA METHYLATION, HISTONE MODIFICATIONS, MICRORNAS (MIRNAS), AND RISK ASSESSMENT. RESULTS: DATA ON HUMAN TOXICITY DUE TO HG EXPOSURE SHOWS BROAD VARIATIONS IN TERMS OF CHEMICAL NATURE, DOSES, AND THE RATE OF EXPOSURE. HG CONSUMPTION EITHER VIA FOODS OR ENVIRONMENTAL SOURCES MAY CREATE DELETERIOUS HEALTH EFFECTS ON VARIOUS PHYSIOLOGICAL SYSTEMS AT LEAST PARTIALLY THROUGH AN EPIGENETIC MECHANISM. CONCLUSION: HG EXPOSURE COULD TRIGGER EPIGENETIC ALTERATIONS, HENCE LEADING TO VARIOUS HUMAN DISORDERS INCLUDING REDUCED NEWBORN CEREBELLUM SIZE, ADVERSE BEHAVIORAL OUTCOMES, ATHEROSCLEROSIS AND MYOCARDIAL INFARCTION. SIMILARLY, IN ADULTS, OCCUPATIONAL HG EXPOSURE HAS BEEN ASSOCIATED WITH AN INCREASED RISK OF AUTOIMMUNITY. IT HAS BEEN REVEALED THAT MIRNAS IN THE WOMAN'S CERVIX ARE A NOVEL RESPONDER TO MATERNAL HG EXPOSURE DURING PREGNANCY. HG-INDUCED EPIGENETIC ALTERATIONS ANALYSIS OF KIDNEY TISSUES SHOWED A SIGNIFICANT INTERRUPTION IN RENAL FUNCTION. DNA METHYLATION AND HISTONE POST-TRANSLATION MODIFICATIONS ARE PREDOMINANT TYPES OF HG EPIGENETIC ALTERATIONS. 2019 15 3210 26 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 16 2093 35 EPIGENETIC EFFECTS FOLLOWING ACUTE AND CHRONIC EXERCISE IN CARDIOVASCULAR DISEASE: A SYSTEMATIC REVIEW. INTRODUCTION: ACUTE EXERCISE AND EXERCISE TRAINING MAY CONFER EPIGENETIC MODIFICATIONS IN HEALTHY SUBJECTS. EPIGENETIC EFFECTS AFTER EXERCISE HAVE BEEN SHOWED IN PATIENTS WITH CARDIOVASCULAR DISEASE. THE AIM OF THIS SYSTEMATIC REVIEW WAS TO SUMMARIZE THE EVIDENCE FROM AVAILABLE CLINICAL TRIALS THAT STUDY EPIGENETIC ADAPTATIONS AFTER EXERCISE IN PATIENTS WITH CARDIOVASCULAR DISEASE. METHODS: THE SEARCH STRATEGY WAS PERFORMED IN PUBMED AND CENTRAL DATABASES ON ARTICLES PUBLISHED UNTIL SEPTEMBER 2020. STUDIES WITH TITLES AND ABSTRACTS RELEVANT TO EXERCISE EPIGENETIC MODIFICATION APPLIED TO CARDIOVASCULAR PATIENTS WERE FULLY EXAMINED. INCLUSION AND EXCLUSION CRITERIA WERE UTILIZED FOR STUDIES SCREENING. QUALITY ASSESSMENT WITH PEDRO SCALE AND EVALUATION BY TWO INDEPENDENT REVIEWERS WAS PERFORMED. RESULTS: OF THE 1714 ARTICLES RETRIEVED, 88 ARTICLES WERE ASSESSED FOR ELIGIBILITY CRITERIA AND 8 ARTICLES MATCHED OUR SEARCH CRITERIA AND FINALLY INCLUDED IN THE SYSTEMATIC ANALYSIS. THE ACUTE EXERCISE EPIGENETIC (MIRNAS) EFFECTS WERE ASSESSED IN THREE STUDIES AND THE CHRONIC EXERCISE TRAINING EFFECTS (MIRNAS AND DNA METHYLATION) IN SIX STUDIES. THE RESULTS HAVE SHOWN THAT THERE IS POSSIBLY AN ACUTE SIGNIFICANT EXERCISE EFFECT ON EPIGENETIC TARGETS WHICH IS MORE EVIDENT AFTER CHRONIC EXERCISE TRAINING. CONCLUSIONS: BY THE PRESENT SYSTEMATIC REVIEW, WE PROVIDE PRELIMINARY EVIDENCE OF BENEFICIAL EPIGENETIC ADAPTATIONS FOLLOWING ACUTE AND CHRONIC EXERCISE IN PATIENTS WITH CARDIOVASCULAR DISEASE. MORE CONTROLLED STUDIES ARE NEEDED TO CONFIRM SUCH EVIDENCE. 2021 17 6159 32 THE GENETICS AND EPIGENETICS OF FATIGUE. FATIGUE IS A COMMON SYMPTOM AND INCLUDES BOTH PHYSICAL AND MENTAL COMPONENTS. IT CAN BE ASSOCIATED WITH A VARIETY OF DIFFERENT SYNDROMES AND DISEASES, BUT IN MANY CASES IS NOT ASSOCIATED WITH OTHER COMORBID CONDITIONS. MOST HUMANS HAVE EXPERIENCED ACUTE FATIGUE IN RELATION TO DIFFERENT STRESSORS. ACUTE FATIGUE TYPICALLY DECREASES AS THE EFFECT OF THE TRIGGERING FACTOR IS REDUCED AND A NORMAL HOMEOSTATIC BALANCE IS RESTORED. FATIGUE THAT PERSISTS FOR 6 MONTHS OR MORE IS TERMED CHRONIC FATIGUE. CHRONIC FATIGUE (CF) IN COMBINATION WITH A MINIMUM OF 4 OF 8 SYMPTOMS AND THE ABSENCE OF DISEASES THAT COULD EXPLAIN THESE SYMPTOMS, CONSTITUTE THE CASE DEFINITION FOR CHRONIC FATIGUE SYNDROME. IN SPITE OF ITS PREVALENCE, THE BIOLOGY OF FATIGUE IS RELATIVELY POORLY UNDERSTOOD AND BIOLOGICAL MARKERS HAVE NOT YET BEEN IDENTIFIED. THIS LITERATURE SEARCH WAS PERFORMED IN PUBMED TO IDENTIFY RESEARCH ON THE GENETICS AND EPIGENETICS OF FATIGUE. PUBLICATIONS WERE INCLUDED IF FATIGUE WAS A MAJOR TOPIC AND THE TOPIC WAS COMBINED WITH GENETIC AND/OR EPIGENETIC MEASUREMENTS IN ADULT HUMANS. A TOTAL OF 40 PUBLICATIONS WERE IDENTIFIED. ALTHOUGH ALTERED FUNCTIONING IN THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS, THE SEROTONERGIC SYSTEM, AND ASSOCIATIONS WITH INFECTIOUS AGENTS HAVE BEEN IDENTIFIED, THE SEARCH FOR GENETIC OR EPIGENETIC MARKERS OF FATIGUE, EITHER IN THE CONTEXT OF CF OR CHRONIC FATIGUE SYNDROME (CFS) HAS BEEN RELATIVELY UNPRODUCTIVE OR, IN THE CASE OF EPIGENETICS, NONEXISTENT. ALTHOUGH SEVERAL STUDIES, BOTH HYPOTHESIS-TESTING AND HYPOTHESIS-GENERATING, HAVE BEEN PERFORMED TO SEARCH FOR BIOMARKERS, THEY HAVE MOSTLY BEEN UNDERPOWERED, RESTRICTED BY THE HETEROGENEITY OF THE PHENOTYPE, OR LIMITED BY AN UNSYSTEMATIC STUDY DESIGN. TO BE ABLE TO CONFIRM THE HYPOTHESIS THAT RISK FOR, OR LEVELS OF, FATIGUE ARE INFLUENCED BY THE GENETIC OR EPIGENETIC BACKGROUND OF AN INDIVIDUAL, STUDIES NEED TO BE BASED ON LARGER SAMPLE SIZES WITH A MORE CLEARLY DEFINED PHENOTYPE. STUDIES NEED TO FOCUS NOT ONLY ON THE INFLUENCE OF A SINGLE ASPECT SUCH AS SINGLE NUCLEOTIDE POLYMORPHISMS (SNPS) OR DIFFERENTIAL GENE EXPRESSION ON DISEASE RISK OR STATE, BUT ALSO ON THE SYSTEMS BIOLOGY BEHIND THE DISEASE IN COMBINATION WITH INFORMATION ON ENVIRONMENTAL INFLUENCES AND VALIDATION OF FINDINGS IN FUNCTIONAL STUDIES. 2010 18 266 34 ADVERSE OUTCOME PATHWAYS FOR IONIZING RADIATION AND BREAST CANCER INVOLVE DIRECT AND INDIRECT DNA DAMAGE, OXIDATIVE STRESS, INFLAMMATION, GENOMIC INSTABILITY, AND INTERACTION WITH HORMONAL REGULATION OF THE BREAST. KNOWLEDGE ABOUT ESTABLISHED BREAST CARCINOGENS CAN SUPPORT IMPROVED AND MODERNIZED TOXICOLOGICAL TESTING METHODS BY IDENTIFYING KEY MECHANISTIC EVENTS. IONIZING RADIATION (IR) INCREASES THE RISK OF BREAST CANCER, ESPECIALLY FOR WOMEN AND FOR EXPOSURE AT YOUNGER AGES, AND EVIDENCE OVERALL SUPPORTS A LINEAR DOSE-RESPONSE RELATIONSHIP. WE USED THE ADVERSE OUTCOME PATHWAY (AOP) FRAMEWORK TO OUTLINE AND EVALUATE THE EVIDENCE LINKING IONIZING RADIATION WITH BREAST CANCER FROM MOLECULAR INITIATING EVENTS TO THE ADVERSE OUTCOME THROUGH INTERMEDIATE KEY EVENTS, CREATING A QUALITATIVE AOP. WE IDENTIFIED KEY EVENTS BASED ON REVIEW ARTICLES, SEARCHED PUBMED FOR RECENT LITERATURE ON KEY EVENTS AND IR, AND IDENTIFIED ADDITIONAL PAPERS USING REFERENCES. WE MANUALLY CURATED PUBLICATIONS AND EVALUATED DATA QUALITY. IONIZING RADIATION DIRECTLY AND INDIRECTLY CAUSES DNA DAMAGE AND INCREASES PRODUCTION OF REACTIVE OXYGEN AND NITROGEN SPECIES (RONS). RONS LEAD TO DNA DAMAGE AND EPIGENETIC CHANGES LEADING TO MUTATIONS AND GENOMIC INSTABILITY (GI). PROLIFERATION AMPLIFIES THE EFFECTS OF DNA DAMAGE AND MUTATIONS LEADING TO THE AO OF BREAST CANCER. SEPARATELY, RONS AND DNA DAMAGE ALSO INCREASE INFLAMMATION. INFLAMMATION CONTRIBUTES TO DIRECT AND INDIRECT EFFECTS (EFFECTS IN CELLS NOT DIRECTLY REACHED BY IR) VIA POSITIVE FEEDBACK TO RONS AND DNA DAMAGE, AND SEPARATELY INCREASES PROLIFERATION AND BREAST CANCER THROUGH PRO-CARCINOGENIC EFFECTS ON CELLS AND TISSUE. FOR EXAMPLE, GENE EXPRESSION CHANGES ALTER INFLAMMATORY MEDIATORS, RESULTING IN IMPROVED SURVIVAL AND GROWTH OF CANCER CELLS AND A MORE HOSPITABLE TISSUE ENVIRONMENT. ALL OF THESE EVENTS OVERLAP AT MULTIPLE POINTS WITH EVENTS CHARACTERISTIC OF "BACKGROUND" INDUCTION OF BREAST CARCINOGENESIS, INCLUDING HORMONE-RESPONSIVE PROLIFERATION, OXIDATIVE ACTIVITY, AND DNA DAMAGE. THESE OVERLAPS MAKE THE BREAST PARTICULARLY SUSCEPTIBLE TO IONIZING RADIATION AND REINFORCE THAT THESE BIOLOGICAL ACTIVITIES ARE IMPORTANT CHARACTERISTICS OF CARCINOGENS. AGENTS THAT INCREASE THESE BIOLOGICAL PROCESSES SHOULD BE CONSIDERED POTENTIAL BREAST CARCINOGENS, AND PREDICTIVE METHODS ARE NEEDED TO IDENTIFY CHEMICALS THAT INCREASE THESE PROCESSES. TECHNIQUES ARE AVAILABLE TO MEASURE RONS, DNA DAMAGE AND MUTATION, CELL PROLIFERATION, AND SOME INFLAMMATORY PROTEINS OR PROCESSES. IMPROVED ASSAYS ARE NEEDED TO MEASURE GI AND CHRONIC INFLAMMATION, AS WELL AS THE INTERACTION WITH HORMONALLY DRIVEN DEVELOPMENT AND PROLIFERATION. SEVERAL METHODS MEASURE DIVERSE EPIGENETIC CHANGES, BUT IT IS NOT CLEAR WHICH CHANGES ARE RELEVANT TO BREAST CANCER. IN ADDITION, MOST TOXICOLOGICAL ASSAYS ARE NOT CONDUCTED IN MAMMARY TISSUE, AND SO IT IS A PRIORITY TO EVALUATE IF RESULTS FROM OTHER TISSUES ARE GENERALIZABLE TO BREAST, OR TO CONDUCT ASSAYS IN BREAST TISSUE. DEVELOPING AND APPLYING THESE ASSAYS TO IDENTIFY EXPOSURES OF CONCERN WILL FACILITATE EFFORTS TO REDUCE SUBSEQUENT BREAST CANCER RISK. 2020 19 1844 30 EFFECTS OF THE LIFESTYLE HABITS IN BREAST CANCER TRANSCRIPTIONAL REGULATION. THROUGH RESEARCH CARRIED OUT IN THE LAST 25 YEARS ABOUT THE BREAST CANCER ETIOLOGY, IT HAS BEEN POSSIBLE TO ESTIMATE THAT LESS THAN 10 % OF PATIENTS WHO ARE DIAGNOSED WITH THE CONDITION ARE CARRIERS OF SOME GERMLINE OR SOMATIC MUTATION. THE CLINICAL REPORTS OF BREAST CANCER PATIENTS WITH HEALTHY TWINS AND THE DEVELOPMENT OF DISEASE IN WOMEN WITHOUT HIGH PENETRANCE MUTATIONS DETECTED, WARN THE PARTICIPATION MORE FACTORS IN THE TRANSFORMATION PROCESS. THE HIGH INCIDENCE OF MAMMARY ADENOCARCINOMA IN THE MODERN WOMAN AND THE URGENT NEED FOR NEW METHODS OF PREVENTION AND EARLY DETECTION HAVE DEMANDED MORE INFORMATION ABOUT THE ROLE THAT ENVIRONMENT AND LIFESTYLE HAVE ON THE TRANSFORMATION OF MAMMARY GLAND EPITHELIAL CELLS. OBESITY, ALCOHOLISM AND SMOKING ARE FACTORS THAT HAVE SHOWN A CLOSE CORRELATION WITH THE RISK OF DEVELOPING BREAST CANCER. AND ALTHOUGH THESE CONDITIONS AFFECT DIFFERENT CELL REGULATION LEVELS, THE STUDY OF ITS EFFECTS IN THE MECHANISMS OF TRANSCRIPTIONAL AND EPIGENETIC REGULATION IS CONSIDERED CRITICAL FOR A BETTER UNDERSTANDING OF THE LOSS OF IDENTITY OF EPITHELIAL CELLS DURING CARCINOGENESIS OF THIS TISSUE. THE MAIN OBJECTIVE OF THIS REVIEW WAS TO ESTABLISH THE IMPORTANCE OF CHANGES OCCURRING TO TRANSCRIPTIONAL LEVEL IN THE MAMMARY GLAND AS A CONSEQUENCE OF ACUTE OR CHRONIC EXPOSURE TO HARMFUL PRODUCTS SUCH AS OBESITY-CAUSING FOODS, ETHANOL AND CIGARETTE SMOKE COMPONENTS. AT ANALYZE THE MAIN STUDIES RELATED TO TOPIC, IT HAS CONCLUDED THAT THE UNDERSTANDING OF EFFECTS CAUSED BY THE LIFESTYLE FACTORS IN PERFORMANCE OF THE TRANSCRIPTIONAL MECHANISMS THAT DETERMINE GENE EXPRESSION OF THE MAMMARY GLAND EPITHELIAL CELLS, MAY HELP EXPLAIN THE DEVELOPMENT OF THIS DISEASE IN WOMEN WITHOUT GENETIC PROPENSITY AND DIFFERENT PHENOTYPIC MANIFESTATIONS OF THIS CANCER TYPE. 2016 20 6562 26 TRANSIENT AND PERMANENT CHANGES IN DNA METHYLATION PATTERNS IN INORGANIC ARSENIC-MEDIATED EPITHELIAL-TO-MESENCHYMAL TRANSITION. CHRONIC LOW DOSE INORGANIC ARSENIC EXPOSURE CAUSES CELLS TO TAKE ON AN EPITHELIAL-TO-MESENCHYMAL PHENOTYPE, WHICH IS A CRUCIAL PROCESS IN CARCINOGENESIS. INORGANIC ARSENIC IS NOT A MUTAGEN AND THUS EPIGENETIC ALTERATIONS HAVE BEEN IMPLICATED IN THIS PROCESS. INDEED, DURING THE EPITHELIAL-TO-MESENCHYMAL TRANSITION, MORPHOLOGIC CHANGES TO CELLS CORRELATE WITH CHANGES IN CHROMATIN STRUCTURE AND GENE EXPRESSION, ULTIMATELY DRIVING THIS PROCESS. HOWEVER, STUDIES ON THE EFFECTS OF INORGANIC ARSENIC EXPOSURE/WITHDRAWAL ON THE EPITHELIAL-TO-MESENCHYMAL TRANSITION AND THE IMPACT OF EPIGENETIC ALTERATIONS IN THIS PROCESS ARE LIMITED. IN THIS STUDY WE USED HIGH-RESOLUTION MICROARRAY ANALYSIS TO MEASURE THE CHANGES IN DNA METHYLATION IN CELLS UNDERGOING INORGANIC ARSENIC-INDUCED EPITHELIAL-TO-MESENCHYMAL TRANSITION, AND ON THE REVERSAL OF THIS PROCESS, AFTER REMOVAL OF THE INORGANIC ARSENIC EXPOSURE. WE FOUND THAT CELLS EXPOSED TO CHRONIC, LOW-DOSE INORGANIC ARSENIC EXPOSURE SHOWED 30,530 SITES WERE DIFFERENTIALLY METHYLATED, AND WITH INORGANIC ARSENIC WITHDRAWAL SEVERAL DIFFERENTIAL METHYLATED SITES WERE REVERSED, ALBEIT NOT COMPLETELY. FURTHERMORE, THESE CHANGES IN DNA METHYLATION MAINLY CORRELATED WITH CHANGES IN GENE EXPRESSION AT MOST SITES TESTED BUT NOT AT ALL. THIS STUDY SUGGESTS THAT DNA METHYLATION CHANGES ON GENE EXPRESSION ARE NOT CLEAR-CUT AND PROVIDE A PLATFORM TO BEGIN TO UNCOVER THE RELATIONSHIP BETWEEN DNA METHYLATION AND GENE EXPRESSION, SPECIFICALLY WITHIN THE CONTEXT OF INORGANIC ARSENIC TREATMENT. 2017