1 2940 174 GENETIC AND EPIGENETIC ALTERATIONS IN NORMAL AND SENSITIVE COPD-DISEASED HUMAN BRONCHIAL EPITHELIAL CELLS REPEATEDLY EXPOSED TO AIR POLLUTION-DERIVED PM(2.5). EVEN THOUGH CLINICAL, EPIDEMIOLOGICAL AND TOXICOLOGICAL STUDIES HAVE PROGRESSIVELY PROVIDED A BETTER KNOWLEDGE OF THE UNDERLYING MECHANISMS BY WHICH AIR POLLUTION-DERIVED PARTICULATE MATTER (PM) EXERTS ITS HARMFUL HEALTH EFFECTS, FURTHER IN VITRO STUDIES ON RELEVANT CELL SYSTEMS ARE STILL NEEDED. HENCE, AIMING OF GETTING CLOSER TO THE HUMAN IN VIVO CONDITIONS, PRIMARY HUMAN BRONCHIAL EPITHELIAL CELLS DERIVED FROM NORMAL SUBJECTS (NHBE) OR SENSITIVE CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD)-DISEASED PATIENTS (DHBE) WERE DIFFERENTIATED AT THE AIR-LIQUID INTERFACE. THEREAFTER, THEY WERE REPEATEDLY EXPOSED TO AIR POLLUTION-DERIVED PM(2.5) TO STUDY THE OCCURRENCE OF SOME RELEVANT GENETIC AND/OR EPIGENETIC ENDPOINTS. CONCENTRATION-, EXPOSURE- AND SEASON-DEPENDENT INCREASES OF OH-B[A]P METABOLITES IN NHBE, AND TO A LESSER EXTENT, COPD-DHBE CELLS WERE REPORTED; HOWEVER, THERE WERE MORE TETRA-OH-B[A]P AND 8-OHDG DNA ADDUCTS IN COPD-DHBE CELLS. NO INCREASE IN PRIMARY DNA STRAND BREAK NOR CHROMOSOMAL ABERRATION WAS OBSERVED IN REPEATEDLY EXPOSED CELLS. TELOMERE LENGTH AND TELOMERASE ACTIVITY WERE MODIFIED IN A CONCENTRATION- AND EXPOSURE-DEPENDENT MANNER IN NHBE AND PARTICULARLY COPD-DHBE CELLS. THERE WERE A GLOBAL DNA HYPOMETHYLATION, A P16 GENE PROMOTER HYPERMETHYLATION, AND A DECREASING DNA METHYLTRANSFERASE ACTIVITY IN NHBE AND NOTABLY COPD-DHBE CELLS REPEATEDLY EXPOSED. CHANGES IN SITE-SPECIFIC METHYLATION, ACETYLATION, AND PHOSPHORYLATION OF HISTONE H3 (I.E., H3K4ME3, H3K9AC, H3K27AC, AND H3S10PH) AND RELATED ENZYME ACTIVITIES OCCURRED IN A CONCENTRATION- AND EXPOSURE-DEPENDENT MANNER IN ALL THE REPEATEDLY EXPOSED CELLS. COLLECTIVELY, THESE RESULTS HIGHLIGHTED THE KEY ROLE PLAYED BY GENETIC AND EVEN EPIGENETIC EVENTS IN NHBE AND PARTICULARLY SENSITIVE COPD-DHBE CELLS REPEATEDLY EXPOSED TO AIR POLLUTION-DERIVED PM(2.5) AND THEIR DIFFERENT RESPONSIVENESS. WHILE THESE SPECIFIC EPIGENETIC CHANGES HAVE BEEN ALREADY DESCRIBED IN COPD AND EVEN LUNG CANCER PHENOTYPES, OUR FINDINGS SUPPORTED THAT, TOGETHER WITH GENETIC EVENTS, THESE EPIGENETIC EVENTS COULD DRAMATICALLY CONTRIBUTE TO THE SHIFT FROM HEALTHY TO DISEASED PHENOTYPES FOLLOWING REPEATED EXPOSURE TO RELATIVELY LOW DOSES OF AIR POLLUTION-DERIVED PM(2.5). 2017 2 1443 92 DIFFERENTIAL RESPONSES OF HEALTHY AND CHRONIC OBSTRUCTIVE PULMONARY DISEASED HUMAN BRONCHIAL EPITHELIAL CELLS REPEATEDLY EXPOSED TO AIR POLLUTION-DERIVED PM(4). WHILE THE KNOWLEDGE OF THE UNDERLYING MECHANISMS BY WHICH AIR POLLUTION-DERIVED PARTICULATE MATTER (PM) EXERTS ITS HARMFUL HEALTH EFFECTS IS STILL INCOMPLETE, DETAILED IN VITRO STUDIES ARE HIGHLY NEEDED. WITH THE AIM OF GETTING CLOSER TO THE HUMAN IN VIVO CONDITIONS AND BETTER INTEGRATING A NUMBER OF FACTORS RELATED TO PRE-EXISTING CHRONIC PULMONARY INFLAMMATORY, WE SOUGHT TO DEVELOP PRIMARY CULTURES OF NORMAL HUMAN BRONCHIAL EPITHELIAL (NHBE) CELLS AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD)-DISEASED HUMAN BRONCHIAL EPITHELIAL (DHBE) CELLS, GROWN AT THE AIR-LIQUID INTERFACE. PAN-CYTOKERATIN AND MUC5AC IMMUNOSTAINING CONFIRMED THE SPECIFIC CELL-TYPES OF BOTH THESE HEALTHY AND DISEASED CELL MODELS AND SHOWED THEY ARE CLOSED TO HUMAN BRONCHIAL EPITHELIA. THEREAFTER, HEALTHY AND DISEASED CELLS WERE REPEATEDLY EXPOSED TO AIR POLLUTION-DERIVED PM(4) AT THE NON-CYTOTOXIC CONCENTRATION OF 5 MUG/CM(2). THE DIFFERENCES BETWEEN THE OXIDATIVE AND INFLAMMATORY STATES IN NON-EXPOSED NHBE AND COPD-DHBE CELLS INDICATED THAT DISEASED CELLS CONSERVED THEIR SPECIFIC PHYSIOPATHOLOGICAL CHARACTERISTICS. INCREASES IN BOTH OXIDATIVE DAMAGE AND CYTOKINE SECRETION WERE REPORTED IN REPEATEDLY EXPOSED NHBE CELLS AND PARTICULARLY IN COPD-DHBE CELLS. DISEASED CELLS REPEATEDLY EXPOSED HAD LOWER CAPACITIES TO METABOLIZE THE ORGANIC CHEMICALS-COATED ONTO THE AIR-POLLUTION-DERIVED PM(4), SUCH AS BENZO[A]PYRENE (B[A]P), BUT SHOWED HIGHER SENSIBILITY TO THE FORMATION OF OH-B[A]P DNA ADDUCTS, BECAUSE THEIR DISEASED STATE POSSIBLY AFFECTED THEIR DEFENSES. DIFFERENTIAL PROFILES OF EPIGENETIC HALLMARKS (I.E., GLOBAL DNA HYPOMETHYLATION, P16 PROMOTER HYPERMETHYLATION, TELOMERE LENGTH SHORTENING, TELOMERASE ACTIVATION, AND HISTONE H3 MODIFICATIONS) OCCURRED IN REPEATEDLY EXPOSED NHBE AND PARTICULARLY IN COPD-DHBE CELLS. TAKEN TOGETHER, THESE RESULTS CLOSELY SUPPORTED THE HIGHEST RESPONSIVENESS OF COPD-DHBE CELLS TO A REPEATED EXPOSURE TO AIR POLLUTION-DERIVED PM(4). THE USE OF THESE INNOVATIVE IN VITRO EXPOSURE SYSTEMS SUCH AS NHBE AND COPD-DHBE CELLS COULD THEREFORE BE CONSIDER AS A VERY USEFUL AND POWERFUL PROMISING TOOL IN THE FIELD OF THE RESPIRATORY TOXICOLOGY, TAKING INTO ACCOUNT SENSITIVE INDIVIDUALS. 2016 3 3099 45 GENOMIC DNA METHYLATION SIGNATURES IN DIFFERENT TISSUES AFTER AMBIENT AIR PARTICULATE MATTER EXPOSURE. DNA METHYLATION (5-MC) IS ONE OF THE SEVERAL EPIGENETIC MARKERS, AND IS GENERALLY ASSOCIATED WITH THE INHIBITION OF GENE EXPRESSION. BOTH HYPER AND HYPO DNA METHYLATION ARE ASSOCIATED WITH THE DISEASES. EXPOSURE TO FINE PARTICLES WITH A DIAMETER OF 2.5 MUM OR LESS (PM(2.5)) IS A PERVASIVE RISK FACTOR FOR CARDIOPULMONARY MORTALITY, METABOLIC DISORDERS, COGNITION DAMAGE, AND ETC.. RECENT REPORTS POINTED TOWARD THAT THESE DISEASES WERE ASSOCIATED WITH THE ALTERED DNA METHYLATION LEVEL OF SOME SPECIFIC-GENE, POTENTIALLY SUGGESTING THAT THE DNA METHYLATION ALTERATION WAS INVOLVED IN THE HEALTH HAZARD DERIVED FROM THE PM(2.5) EXPOSURE. IN THIS STUDY, WE SYSTEMATICALLY INVESTIGATED THE GLOBAL DNA METHYLATION LEVEL OF MOST TISSUES, INCLUDING LUNG, HEART, TESTIS, THYMUS, SPLEEN, EPIDIDYMAL FAT, HIPPOCAMPUS, KIDNEY, LIVE, AFTER SHORT AND LONG TERM PM(2.5) EXPOSURE. AFTER ACUTE PM(2.5) EXPOSURE, THE GLOBAL HYPO-METHYLATION IN DNA WAS OBSERVED IN LUNG AND HEART. NOTABLY, AFTER CHRONIC PM(2.5) EXPOSURE, LEVEL OF GLOBAL DNA METHYLATION DECREASED IN MOST ORGANS WHICH INCLUDED LUNG, TESTIS, THYMUS, SPLEEN, EPIDIDYMAL FAT, HIPPOCAMPUS AND BLOOD. THE PRESENT STUDY SYSTEMATICALLY DEMONSTRATED THE GLOBAL DNA METHYLATION CHANGES BY PM(2.5) EXPOSURE, AND PUT FORWARD A POSSIBLE ORIENTATION FOR FURTHER EXPLORING THE EFFECTS OF AMBIENT AIR PARTICLES EXPOSURE ON THE SPECIFIC ORGANS. 2019 4 642 46 BIOMARKERS OF PARTICULATE MATTER EXPOSURE IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE: A SYSTEMATIC REVIEW. BACKGROUND: IN RECENT YEARS, AMBIENT PARTICULATE MATTER (PM) EXPOSURE HAS BEEN STRONGLY LINKED WITH HEALTH EFFECTS. ELEVATED LEVELS OF PM IN POLLUTED AIR HAVE BEEN CORRELATED WITH THE ONSET AND DEVELOPMENT OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). THIS SYSTEMATIC REVIEW WAS CONDUCTED TO EVALUATE BIOMARKERS THAT COULD REFLECT THE EFFECTS OF PM EXPOSURE IN PATIENTS WITH COPD. METHODS: WE PERFORMED A SYSTEMATIC REVIEW OF STUDIES PUBLISHED ON BIOMARKERS ASSOCIATED WITH PM EXPOSURE IN PATIENTS WITH COPD BETWEEN JANUARY 01, 2012 AND JUNE 30, 2022 IN PUBMED/MEDLINE, EMBASE, AND COCHRANE DATABASES. STUDIES THAT INCLUDED DATA ON BIOMARKERS WITH COPD EXPOSED PM WERE ELIGIBLE FOR INCLUSION. BIOMARKERS WERE CLASSIFIED INTO 4 GROUPS ACCORDING TO THEIR MECHANISMS. RESULTS: OF THE 105 STUDIES IDENTIFIED, 22 WERE INCLUDED IN THIS STUDY. NEARLY 50 BIOMARKERS HAVE BEEN PROPOSED IN THE STUDIES INCLUDED IN THIS REVIEW, AND THE MOST STUDIED IN RELATION TO PM ARE SEVERAL INTERLEUKINS. VARIOUS MECHANISMS HAVE BEEN REPORTED BY WHICH PM INDUCES AND AGGRAVATES COPD. SIX STUDIES RELATED TO OXIDATIVE STRESS, ONE RELATED TO DIRECT EFFECT OF INNATE AND ADAPTIVE IMMUNE SYSTEMS, 16 ASSOCIATED WITH GENETIC REGULATION OF INFLAMMATION, AND TWO RELATED TO EPIGENETIC REGULATION OF PHYSIOLOGY AND SUSCEPTIBILITY WERE FOUND. BIOMARKERS RELATED TO THESE MECHANISMS WERE DETECTED IN SERUM, SPUTUM, URINE, EXHALED BREATH CONCENTRATION (EBC), AND SHOWED VARIOUS CORRELATIONS WITH PM IN COPD. CONCLUSIONS: VARIOUS BIOMARKERS HAVE SHOWN POTENTIAL IN PREDICTING THE EXTENT OF PM EXPOSURE IN COPD PATIENTS. FUTURE STUDIES ARE NEEDED TO ESTABLISH RECOMMENDATIONS FOR REGULATION TO REDUCE AIRBORNE PM, WHICH COULD BE USED TO DEVELOP STRATEGIES FOR PREVENTION AND MANAGEMENT OF ENVIRONMENTAL RESPIRATORY DISEASES. 2023 5 3106 42 GENOMICS AND THE RESPIRATORY EFFECTS OF AIR POLLUTION EXPOSURE. ADVERSE HEALTH EFFECTS FROM AIR POLLUTANTS REMAIN IMPORTANT, DESPITE IMPROVEMENT IN AIR QUALITY IN THE PAST FEW DECADES. THE EXACT MECHANISMS OF LUNG INJURY FROM EXPOSURE TO AIR POLLUTANTS ARE NOT YET FULLY UNDERSTOOD. STUDYING THE GENOME (E.G. SINGLE-NUCLEOTIDE POLYMORPHISMS (SNP) ), EPIGENOME (E.G. METHYLATION OF GENES), TRANSCRIPTOME (MRNA EXPRESSION) AND MICRORNAOME (MICRORNA EXPRESSION) HAS THE POTENTIAL TO IMPROVE OUR UNDERSTANDING OF THE ADVERSE EFFECTS OF AIR POLLUTANTS. GENOME-WIDE ASSOCIATION STUDIES OF SNP HAVE DETECTED SNP ASSOCIATED WITH RESPIRATORY PHENOTYPES; HOWEVER, TO DATE, ONLY CANDIDATE GENE STUDIES OF AIR POLLUTION EXPOSURE HAVE BEEN PERFORMED. CHANGES IN EPIGENETIC PROCESSES, SUCH DNA METHYLATION THAT LEADS TO GENE SILENCING WITHOUT ALTERING THE DNA SEQUENCE, OCCUR WITH AIR POLLUTANT EXPOSURE, ESPECIALLY GLOBAL AND GENE-SPECIFIC METHYLATION CHANGES. RESPIRATORY CELL LINE AND ANIMAL MODELS DEMONSTRATE DISTINCT GENE EXPRESSION SIGNATURES IN THE TRANSCRIPTOME, ARISING FROM EXPOSURE TO PARTICULATE MATTER OR OZONE. PARTICULATE MATTER AND OTHER ENVIRONMENTAL TOXINS ALTER EXPRESSION OF MICRORNA, WHICH ARE SHORT NON-CODING RNA THAT REGULATE GENE EXPRESSION. WHILE IT IS CLEARLY IMPORTANT TO CONTAIN RISING LEVELS OF AIR POLLUTION, STRATEGIES ALSO NEED TO BE DEVELOPED TO MINIMIZE THE DAMAGING EFFECTS OF AIR POLLUTANT EXPOSURE ON THE LUNG, ESPECIALLY FOR PATIENTS WITH CHRONIC LUNG DISEASE AND FOR PEOPLE AT RISK OF FUTURE LUNG DISEASE. CAREFUL STUDY OF GENOMIC RESPONSES WILL IMPROVE OUR UNDERSTANDING OF MECHANISMS OF LUNG INJURY FROM AIR POLLUTION AND ENABLE FUTURE CLINICAL TESTING OF INTERVENTIONS AGAINST THE TOXIC EFFECTS OF AIR POLLUTANTS. 2012 6 540 47 ATMOSPHERIC FINE PARTICULATE MATTER AND EPITHELIAL MESENCHYMAL TRANSITION IN PULMONARY CELLS: STATE OF THE ART AND CRITICAL REVIEW OF THE IN VITRO STUDIES. EXPOSURE TO FINE PARTICULATE MATTER (PM(2.5)) HAS BEEN ASSOCIATED WITH SEVERAL DISEASES INCLUDING ASTHMA, CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) AND LUNG CANCER. MECHANISMS SUCH AS OXIDATIVE STRESS AND INFLAMMATION ARE WELL-DOCUMENTED AND ARE CONSIDERED AS THE STARTING POINT OF SOME OF THE PATHOLOGICAL RESPONSES. HOWEVER, A NUMBER OF STUDIES ALSO FOCUSED ON EPITHELIAL-MESENCHYMAL TRANSITION (EMT), WHICH IS A BIOLOGICAL PROCESS INVOLVED IN FIBROTIC DISEASES AND CANCER PROGRESSION NOTABLY VIA METASTASIS INDUCTION. UP UNTIL NOW, EMT WAS WIDELY REPORTED IN VIVO AND IN VITRO IN VARIOUS CELL TYPES BUT INVESTIGATIONS DEALING WITH IN VITRO STUDIES OF PM(2.5) INDUCED EMT IN PULMONARY CELLS ARE LIMITED. FURTHER, FEW INVESTIGATIONS COMBINED THE NECESSARY ENDPOINTS FOR VALIDATION OF THE EMT STATE IN CELLS: SUCH AS EXPRESSION OF SEVERAL SURFACE, CYTOSKELETON OR EXTRACELLULAR MATRIX BIOMARKERS AND ACTIVATION OF TRANSCRIPTION MARKERS AND EPIGENETIC FACTORS. STUDIES EXPLORED VARIOUS CELL TYPES, CULTURED UNDER DIFFERING CONDITIONS AND EXPOSED FOR VARIOUS DURATIONS TO DIFFERENT DOSES. SUCH UNHARMONIZED PROTOCOLS (1) MIGHT INTRODUCE BIAS, (2) MAKE DIFFICULT COMPARISON OF RESULTS AND (3) PRECLUDE REACHING A DEFINITIVE CONCLUSION REGARDING THE ABILITY OF AIRBORNE PM(2.5) TO INDUCE EMT IN PULMONARY CELLS. SOME QUESTIONS REMAIN, IN PARTICULAR THE SPECIFIC PM(2.5) COMPONENTS RESPONSIBLE FOR EMT TRIGGERING. THE AIM OF THIS REVIEW IS TO EXAMINE THE AVAILABLE PM(2.5) INDUCED EMT IN VITRO STUDIES ON PULMONARY CELLS WITH SPECIAL EMPHASIS ON THE CRITICAL PARAMETERS CONSIDERED TO CARRY OUT FUTURE RESEARCH IN THIS FIELD. THIS CLARIFICATION APPEARS NECESSARY FOR PRODUCTION OF RELIABLE AND COMPARABLE RESULTS. 2020 7 6909 46 [TOXIC COMPONENTS OF PM(2.5) AND THEIR TOXICITY MECHANISMS-ON THE TOXICITY OF SULFATE AND CARBON COMPONENTS]. RECENTLY, THE MAIN AIR POLLUTANT HAS BEEN FINE PARTICULATE MATTER (PM(2.5)), WHICH IS TAKEN UP BY THE WHOLE BODY WITH SEVERE ADVERSE HEALTH EFFECTS. THE MAIN CHEMICAL COMPONENTS OF PM(2.5) ARE SALTS OF SULFATE (AND NITRATE) AND CARBONS. HOWEVER, IT REMAINS UNKNOWN WHICH COMPONENTS ARE TOXIC. HERE, THE AUTHOR REVIEWED THE LITERATURES TO DETERMINE WHICH COMPONENTS ARE TOXIC AND THE MAIN MECHANISMS UNDERLYING THEIR TOXICITY. MANY EPIDEMIOLOGICAL STUDIES HAVE SHOWN THAT SULFATE CONCENTRATION IS STRONGLY RELATED TO MORTALITY. HOWEVER, THERE IS NO EXPERIMENTAL EVIDENCE SHOWING THAT SULFATE AT ENVIRONMENTAL CONCENTRATIONS OF PM(2.5) CAUSES CARDIOVASCULAR DISEASE OR OTHER DISEASE. ON THE OTHER HAND, CARBON COMPONENTS SUCH AS ELEMENTARY CARBON (EC) PRODUCES HIGH CONCENTRATIONS OF REACTIVE OXYGEN SPECIES (ROS) VIA ITS PHAGOCYTOSIS BY MACROPHAGES, AND ORGANIC CARBON (OC) ALSO PRODUCES HIGH CONCENTRATIONS OF ROS DURING ITS METABOLIC PROCESSES, AND THE ROS CAUSE ACUTE AND CHRONIC INFLAMMATION. THEY CAUSE MANY DISEASES INCLUDING CARDIOVASCULAR DISEASE, ASTHMA AND CANCER. FURTHERMORE, THERE ARE MANY LINES OF EVIDENCE SHOWING THAT EPIGENETIC CHANGES SUCH AS DNA METHYLATION OR MICRORNA EXPRESSION INDUCED BY PARTICULATE MATTERS ALSO INDUCE THE DEVELOPMENT OF MANY DISEASES SUCH AS THOSE MENTIONED ABOVE. IT HAS BEEN REPORTED THAT CARBON COMPONENTS ARE INCORPORATED INTO THE BRAIN AND PRODUCE ROS, AND THAT THE ROS CAUSE DAMAGE TO BRAIN CELLS AND ALZHEIMER'S DISEASE AND COGNITIVE DISORDERS IN THE ELDERLY.FROM THESE LINES OF EVIDENCE, THE AUTHOR WOULD LIKE TO EMPHASIZE THAT THE MAIN TOXICITY OF PM(2.5) IS DUE TO CARBON COMPONENTS, AND IT IS IMPORTANT TO TAKE COUNTERMEASURES TO DECREASE THE CONCENTRATION OF CARBON COMPONENTS IN AMBIENT AIR. 2019 8 228 45 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 9 3738 44 INORGANIC ARSENIC-INDUCED CELLULAR TRANSFORMATION IS COUPLED WITH GENOME WIDE CHANGES IN CHROMATIN STRUCTURE, TRANSCRIPTOME AND SPLICING PATTERNS. BACKGROUND: ARSENIC (AS) EXPOSURE IS A SIGNIFICANT WORLDWIDE ENVIRONMENTAL HEALTH CONCERN. LOW DOSE, CHRONIC ARSENIC EXPOSURE HAS BEEN ASSOCIATED WITH A HIGHER THAN NORMAL RISK OF SKIN, LUNG, AND BLADDER CANCER, AS WELL AS CARDIOVASCULAR DISEASE AND DIABETES. WHILE ARSENIC-INDUCED BIOLOGICAL CHANGES PLAY A ROLE IN DISEASE PATHOLOGY, LITTLE IS KNOWN ABOUT THE DYNAMIC CELLULAR CHANGES RESULTING FROM ARSENIC EXPOSURE AND WITHDRAWAL. RESULTS: IN THESE STUDIES, WE SOUGHT TO UNDERSTAND THE MOLECULAR MECHANISMS BEHIND THE BIOLOGICAL CHANGES INDUCED BY ARSENIC EXPOSURE. A COMPREHENSIVE GLOBAL APPROACH WAS EMPLOYED TO DETERMINE GENOME-WIDE CHANGES TO CHROMATIN STRUCTURE, TRANSCRIPTOME PATTERNS AND SPLICING PATTERNS IN RESPONSE TO CHRONIC LOW DOSE ARSENIC AND ITS SUBSEQUENT WITHDRAWAL. OUR RESULTS SHOW THAT CELLS EXPOSED TO CHRONIC LOW DOSES OF SODIUM ARSENITE HAVE DISTINCT TEMPORAL AND COORDINATED CHROMATIN, GENE EXPRESSION, AND MIRNA CHANGES CONSISTENT WITH DIFFERENTIATION AND ACTIVATION OF MULTIPLE BIOCHEMICAL PATHWAYS. MOST OF THESE TEMPORAL PATTERNS IN GENE EXPRESSION ARE REVERSED WHEN ARSENIC IS WITHDRAWN. HOWEVER, SOME GENE EXPRESSION PATTERNS REMAINED ALTERED, PLAUSIBLY AS A RESULT OF AN ADAPTIVE RESPONSE BY CELLS. ADDITIONALLY, THE CORRELATION OF CHANGES TO GENE EXPRESSION AND CHROMATIN STRUCTURE SOLIDIFY THE ROLE OF CHROMATIN STRUCTURE IN GENE REGULATORY CHANGES DUE TO ARSENITE EXPOSURE. LASTLY, WE SHOW THAT ARSENITE EXPOSURE INFLUENCES GENE REGULATION BOTH AT THE INITIATION OF TRANSCRIPTION AS WELL AS AT THE LEVEL OF SPLICING. CONCLUSIONS: OUR RESULTS SHOW THAT ADAPTATION OF CELLS TO IAS-MEDIATED EMT IS COUPLED TO CHANGES IN CHROMATIN STRUCTURE EFFECTING DIFFERENTIAL TRANSCRIPTIONAL AND SPLICING PATTERNS OF GENES. THESE STUDIES PROVIDE NEW INSIGHTS INTO THE MECHANISM OF IAS-MEDIATED PATHOLOGY, WHICH INCLUDES EPIGENETIC CHROMATIN CHANGES COUPLED WITH CHANGES TO THE TRANSCRIPTOME AND SPLICING PATTERNS OF KEY GENES. 2015 10 2743 41 EXPOSURE TO ULTRAFINE PARTICULATE MATTER INDUCES NF-KAPPABETA MEDIATED EPIGENETIC MODIFICATIONS. EXPOSURE TO ULTRAFINE PARTICULATE MATTER (PM0.1) IS POSITIVELY ASSOCIATED WITH THE ETIOLOGY OF DIFFERENT ACUTE AND CHRONIC DISORDERS; HOWEVER, THE IN-DEPTH BIOLOGICAL IMPRINTS THAT LINK THESE SUBMICRON PARTICLES WITH THE DISTURBANCES IN THE EPIGENOMIC MACHINERY ARE NOT WELL DEFINED. EARLIER, WE SHOWED THAT EXPOSURE TO THESE PARTICLES CAUSES SIGNIFICANT DISTURBANCES IN THE MITOCHONDRIAL MACHINERY AND TRIGGERS PI-3-KINASE MEDIATED DNA DAMAGE RESPONSES. IN THE PRESENT STUDY, WE AIMED TO FURTHER UNDERSTAND THE EPIGENOMIC INSIGHTS OF THE ULTRAFINE PM EXPOSURE. THE HIGHER LEVELS OF INTRACELLULAR REACTIVE OXYGEN SPECIES AND DEPLETED NRF-2 IN ULTRAFINE PM EXPOSED CELLS RECONFIRMED ITS POTENTIAL TO INDUCE OXIDATIVE STRESS. IMPORTANTLY, THE OBSERVED INCREASE IN THE LEVELS OF NF-KAPPABETA AND ASSOCIATED CYTOKINES AMONG EXPOSED CELLS SUGGESTED THE ACTIVATION OF NF-KAPPABETA MEDIATED INFLAMMATORY LOOP WHICH POTENTIALLY SERVES AS A PLATFORM FOR INITIATING EPIGENETIC INSINUATIONS. THIS FACT WAS STRONGLY SUPPORTED BY THE ALTERED MIRNA EXPRESSION PROFILE OF THE ULTRAFINE PM EXPOSED CELLS. THESE NF-KAPPABETA INDUCED MIRNA ALTERATIONS WERE ALSO FOUND TO BE ASSOCIATED WITH OTHER EPIGENETIC TARGETS AS THE EXPOSED CELLS SHOWED HIGHER EXPRESSION LEVELS OF DNA METHYLTRANSFERASES WHICH POSITIVELY CORRESPONDED WITH THE GLOBAL CHANGES IN DNA METHYLATION LEVELS. UPON FURTHER ANALYSIS, SIGNIFICANT ALTERATIONS IN HISTONE CODE WERE ALSO REPORTED IN ULTRAFINE PM EXPOSED CELLS. CONCLUSIVELY OUR RESULTS SUGGESTED THAT NF-KAPPABETA ACTS AS AN INFLAMMATORY SWITCH THAT POSSESSES THE POTENTIAL TO INDUCE GENOME-WIDE EPIGENETIC MODIFICATION UPON ULTRAFINE PM EXPOSURE. 2019 11 474 29 ARSENIC BIOTRANSFORMATION AS A CANCER PROMOTING FACTOR BY INDUCING DNA DAMAGE AND DISRUPTION OF REPAIR MECHANISMS. CHRONIC EXPOSURE TO ARSENIC IN DRINKING WATER POSES A MAJOR GLOBAL HEALTH CONCERN. POPULATIONS EXPOSED TO HIGH CONCENTRATIONS OF ARSENIC-CONTAMINATED DRINKING WATER SUFFER SERIOUS HEALTH CONSEQUENCES, INCLUDING ALARMING CANCER INCIDENCE AND DEATH RATES. ARSENIC IS BIOTRANSFORMED THROUGH SEQUENTIAL ADDITION OF METHYL GROUPS, ACQUIRED FROM S-ADENOSYLMETHIONINE (SAM). METABOLISM OF ARSENIC GENERATES A VARIETY OF GENOTOXIC AND CYTOTOXIC SPECIES, DAMAGING DNA DIRECTLY AND INDIRECTLY, THROUGH THE GENERATION OF REACTIVE OXIDATIVE SPECIES AND INDUCTION OF DNA ADDUCTS, STRAND BREAKS AND CROSS LINKS, AND INHIBITION OF THE DNA REPAIR PROCESS ITSELF. SINCE SAM IS THE METHYL GROUP DONOR USED BY DNA METHYLTRANSFERASES TO MAINTAIN NORMAL EPIGENETIC PATTERNS IN ALL HUMAN CELLS, ARSENIC IS ALSO POSTULATED TO AFFECT MAINTENANCE OF NORMAL DNA METHYLATION PATTERNS, CHROMATIN STRUCTURE, AND GENOMIC STABILITY. THE BIOLOGICAL PROCESSES UNDERLYING THE CANCER PROMOTING FACTORS OF ARSENIC METABOLISM, RELATED TO DNA DAMAGE AND REPAIR, WILL BE DISCUSSED HERE. 2011 12 904 42 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 13 5193 36 PRENATAL EXPOSURE TO ENVIRONMENTAL PRO-OXIDANTS INDUCES MITOCHONDRIA-MEDIATED EPIGENETIC CHANGES: A CROSS-SECTIONAL PILOT STUDY. MITOCHONDRIA PLAY A CENTRAL ROLE IN MAINTAINING CELLULAR AND METABOLIC HOMEOSTASIS DURING VITAL DEVELOPMENT CYCLES OF FOETAL GROWTH. OPTIMAL MITOCHONDRIAL FUNCTIONS ARE IMPORTANT NOT ONLY TO SUSTAIN ADEQUATE ENERGY PRODUCTION BUT ALSO FOR REGULATED EPIGENETIC PROGRAMMING. HOWEVER, THESE ORGANELLES ARE SUBTLE TARGETS OF ENVIRONMENTAL EXPOSURES, AND ANY PERTURBANCE IN THE DEFINED MITOCHONDRIAL MACHINERY DURING THE DEVELOPMENTAL STAGE CAN LEAD TO THE RE-PROGRAMMING OF THE FOETAL EPIGENETIC LANDSCAPE. AS THESE MODIFICATIONS CAN BE TRANSFERRED TO SUBSEQUENT GENERATIONS, WE HEREIN PERFORMED A CROSS-SECTIONAL STUDY TO HAVE AN IN-DEPTH UNDERSTANDING OF THIS INTRICATE PHENOMENON. THE STUDY WAS CONDUCTED WITH TWO ARMS: WHEREAS THE FIRST GROUP CONSISTED OF IN UTERO PRO-OXIDANT EXPOSED INDIVIDUALS AND THE SECOND GROUP INCLUDED CONTROLS. OUR RESULTS SHOWED HIGHER LEVELS OF OXIDATIVE MTDNA DAMAGE AND ASSOCIATED INTEGRATED STRESS RESPONSE AMONG THE EXPOSED INDIVIDUALS. THESE DISTURBANCES WERE FOUND TO BE CLOSELY RELATED TO THE OBSERVED DISCREPANCIES IN MITOCHONDRIAL BIOGENESIS. THE EXPOSED GROUP SHOWED MTDNA HYPERMETHYLATION AND CHANGES IN ALLIED MITOCHONDRIAL FUNCTIONING. ALTERED EXPRESSION OF MITOMIRS AND THEIR RESPECTIVE TARGET GENES IN THE EXPOSED GROUP INDICATED THE POSSIBILITIES OF A DISTURBED MITOCHONDRIAL-NUCLEAR CROSS TALK. THIS WAS FURTHER CONFIRMED BY THE MODIFIED ACTIVITY OF THE MITOCHONDRIAL STRESS REGULATORS AND PRO-INFLAMMATORY MEDIATORS AMONG THE EXPOSED GROUP. IMPORTANTLY, THE DISTURBED DNMT FUNCTIONING, HYPERMETHYLATION OF NUCLEAR DNA, AND HIGHER DEGREE OF POST-TRANSLATIONAL HISTONE MODIFICATIONS ESTABLISHED THE EXISTENCE OF ABERRANT EPIGENETIC MODIFICATIONS IN THE EXPOSED INDIVIDUALS. OVERALL, OUR RESULTS DEMONSTRATE THE FIRST MOLECULAR INSIGHTS OF IN UTERO PRO-OXIDANT EXPOSURE ASSOCIATED CHANGES IN THE MITOCHONDRIAL-EPIGENETIC AXIS. ALTHOUGH, OUR STUDY MIGHT NOT CEMENT AN EXPOSURE-RESPONSE RELATIONSHIP FOR ANY PARTICULAR ENVIRONMENTAL PRO-OXIDANT, BUT SUFFICE TO ESTABLISH A DOGMA OF MITO-EPIGENETIC REPROGRAMMING AT INTRAUTERINE MILIEU WITH CHRONIC ILLNESS, A HITHERTO UNREPORTED INTERACTION. 2022 14 3837 30 IONIZING RADIATION-INDUCED OXIDATIVE STRESS, EPIGENETIC CHANGES AND GENOMIC INSTABILITY: THE PIVOTAL ROLE OF MITOCHONDRIA. PURPOSE: TO REVIEW THE DATA CONCERNING THE ROLE OF ENDOGENOUSLY GENERATED REACTIVE OXYGEN SPECIES (ROS) IN THE NON-TARGETED IONIZING RADIATION (IR) EFFECTS AND IN DETERMINATION OF THE CELL POPULATION'S FATE, BOTH EARLY AFTER EXPOSURE AND AFTER MANY GENERATIONS. CONCLUSIONS: THE SHORT-TERM AS WELL AS CHRONIC OXIDATIVE STRESS RESPONSES MAINLY ARE PRODUCED DUE TO ROS GENERATION BY THE ELECTRON TRANSPORT CHAIN (ETC) OF THE MITOCHONDRIA AND BY THE CYTOPLASMIC NADPH OXIDASES. WHETHER THE INDUCTION OF THE OXIDATIVE STRESS AND ITS CONSEQUENCES OCCUR OR ARE HAMPERED IN A SINGLE CELL LARGELY DEPENDS ON THE INTERACTION BETWEEN THE NUCLEUS AND THE CELLULAR POPULATION OF SEVERAL HUNDRED OR THOUSANDS OF MITOCHONDRIA THAT ARE GENETICALLY HETEROGENEOUS. HIGH INTRA-MITOCHONDRIAL ROS LEVEL IS DAMAGING THE MITOCHONDRIAL (MT) DNA AND ITS MUTATIONS AFFECT THE EPIGENETIC CONTROL MECHANISMS OF THE NUCLEAR (N) DNA, BY DECREASING THE ACTIVITY OF METHYLTRANSFERASES AND THUS, CAUSING GLOBAL DNA HYPOMETHYLATION. THESE CHANGES ARE TRANSMITTED TO THE PROGENY OF THE IRRADIATED CELLS. THE CHRONIC OXIDATIVE STRESS IS THE MAIN CAUSE OF THE LATE POST-RADIATION EFFECTS, INCLUDING CANCER, AND THIS MAKES IT AN IMPORTANT ADVERSE EFFECT OF EXPOSURE TO IR AND A TARGET FOR RADIOLOGICAL PROTECTION. 2015 15 1815 36 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 6790 30 [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 17 860 35 CHROMATIN MODIFICATIONS DURING REPAIR OF ENVIRONMENTAL EXPOSURE-INDUCED DNA DAMAGE: A POTENTIAL MECHANISM FOR STABLE EPIGENETIC ALTERATIONS. EXPOSURES TO ENVIRONMENTAL TOXICANTS AND TOXINS CAUSE EPIGENETIC CHANGES THAT LIKELY PLAY A ROLE IN THE DEVELOPMENT OF DISEASES ASSOCIATED WITH EXPOSURE. THE MECHANISM BEHIND THESE EXPOSURE-INDUCED EPIGENETIC CHANGES IS CURRENTLY UNKNOWN. ONE COMMONALITY BETWEEN MOST ENVIRONMENTAL EXPOSURES IS THAT THEY CAUSE DNA DAMAGE EITHER DIRECTLY OR THROUGH CAUSING AN INCREASE IN REACTIVE OXYGEN SPECIES, WHICH CAN DAMAGE DNA. LIKE TRANSCRIPTION, DNA DAMAGE REPAIR MUST OCCUR IN THE CONTEXT OF CHROMATIN REQUIRING BOTH HISTONE MODIFICATIONS AND ATP-DEPENDENT CHROMATIN REMODELING. THESE CHROMATIN CHANGES AID IN DNA DAMAGE ACCESSIBILITY AND SIGNALING. SEVERAL PROTEINS AND COMPLEXES INVOLVED IN EPIGENETIC SILENCING DURING BOTH DEVELOPMENT AND CANCER HAVE BEEN FOUND TO BE LOCALIZED TO SITES OF DNA DAMAGE. THE CHROMATIN-BASED RESPONSE TO DNA DAMAGE IS CONSIDERED A TRANSIENT EVENT, WITH CHROMATIN BEING RESTORED TO NORMAL AS DNA DAMAGE REPAIR IS COMPLETED. HOWEVER, IN INDIVIDUALS CHRONICALLY EXPOSED TO ENVIRONMENTAL TOXICANTS OR WITH CHRONIC INFLAMMATORY DISEASE, REPEATED DNA DAMAGE-INDUCED CHROMATIN REARRANGEMENT MAY ULTIMATELY LEAD TO PERMANENT EPIGENETIC ALTERATIONS. UNDERSTANDING THE MECHANISM BEHIND EXPOSURE-INDUCED EPIGENETIC CHANGES WILL ALLOW US TO DEVELOP STRATEGIES TO PREVENT OR REVERSE THESE CHANGES. THIS REVIEW FOCUSES ON EPIGENETIC CHANGES AND DNA DAMAGE INDUCED BY ENVIRONMENTAL EXPOSURES, THE CHROMATIN CHANGES THAT OCCUR AROUND SITES OF DNA DAMAGE, AND HOW THESE TRANSIENT CHROMATIN CHANGES MAY LEAD TO HERITABLE EPIGENETIC ALTERATIONS AT SITES OF CHRONIC EXPOSURE. 2014 18 301 45 AIR POLLUTION ASSOCIATED EPIGENETIC MODIFICATIONS: TRANSGENERATIONAL INHERITANCE AND UNDERLYING MOLECULAR MECHANISMS. AIR POLLUTION IS ONE OF THE LEADING CAUSES OF DEATHS IN SOUTHEAST ASIAN COUNTRIES INCLUDING INDIA. EXPOSURE TO AIR POLLUTANTS AFFECTS VITAL CELLULAR MECHANISMS AND IS INTIMATELY LINKED WITH THE ETIOLOGY OF A NUMBER OF CHRONIC DISEASES. EARLIER WORK FROM OUR LABORATORY HAS SHOWN THAT AIRBORNE PARTICULATE MATTER DISTURBS THE MITOCHONDRIAL MACHINERY AND CAUSES SIGNIFICANT DAMAGE TO THE EPIGENOME. MITOCHONDRIAL REACTIVE OXYGEN SPECIES POSSESS THE ABILITY TO TRIGGER REDOX-SENSITIVE SIGNALING MECHANISMS AND INDUCE IRREVERSIBLE EPIGENOMIC CHANGES. THE ELECTROPHILIC NATURE OF REACTIVE METABOLITES CAN DIRECTLY RESULT IN DEPROTONATION OF CYTOSINE AT C-5 POSITION OR INTERFERE WITH THE DNA METHYLTRANSFERASES ACTIVITY TO CAUSE ALTERATIONS IN DNA METHYLATION. IN ADDITION, IT ALSO PERTURBS LEVEL OF CELLULAR METABOLITES CRITICALLY INVOLVED IN DIFFERENT EPIGENETIC PROCESSES LIKE ACETYLATION AND METHYLATION OF HISTONE CODE AND DNA HYPO OR HYPERMETHYLATION. INTERESTINGLY, THESE MODIFICATIONS MAY PERSIST THROUGH DOWNSTREAM GENERATIONS AND RESULT IN THE TRANSGENERATIONAL EPIGENOMIC INHERITANCE. THIS PHENOMENON OF SUBSEQUENT TRANSFER OF EPIGENETIC MODIFICATIONS IS MAINLY ASSOCIATED WITH THE GERM CELLS AND RELIES ON THE GERMLINE STABILITY OF THE EPIGENETIC STATES. OVERALL, THE RECENT LITERATURE SUPPORTS, AND ARGUABLY STRENGTHENS, THE CONTENTION THAT AIR POLLUTION MIGHT CONTRIBUTE TO TRANSMISSION OF EPIMUTATIONS FROM GAMETES TO ZYGOTES BY INVOLVING MITOCHONDRIAL DNA, PARENTAL ALLELE IMPRINTING, HISTONE WITHHOLDING AND NON-CODING RNAS. HOWEVER, LARGER PROSPECTIVE STUDIES USING INNOVATIVE, INTEGRATED EPIGENOME-WIDE METABOLOMIC STRATEGY ARE HIGHLY WARRANTED TO ASSESS THE AIR POLLUTION INDUCED TRANSGENERATIONAL EPIGENETIC INHERITANCE AND ASSOCIATED HUMAN HEALTH EFFECTS. 2019 19 6562 35 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 20 5174 36 PREDICTIVE AND PROGNOSTIC BIOMARKERS OF RESPIRATORY DISEASES DUE TO PARTICULATE MATTER EXPOSURE. AIR POLLUTION IS GETTING SEVERE AND CONCERNS ABOUT ITS TOXICITY EFFECTS ON AIRWAY AND LUNG DISEASE ARE ALSO INCREASING. PARTICULATE MATTER (PM) IS MAJOR COMPONENT OF AIR POLLUTANT. IT CAUSES RESPIRATORY DISEASES, SUCH AS ASTHMA, CHRONIC OBSTRUCTIVE PULMONARY DISEASE, LUNG CANCER, AND SO ON. PM PARTICLES ENTER THE AIRWAY AND LUNG BY INHALATION, CAUSING DAMAGES TO THEM. ESPECIALLY, PM(2.5) CAN PENETRATE INTO THE ALVEOLUS AND PASS TO THE SYSTEMIC CIRCULATION. IT CAN AFFECT THE CARDIOPULMONARY SYSTEM AND CAUSE CARDIOPULMONARY DISORDERS. IN THIS REVIEW, WE FOCUSED ON PM-INDUCING TOXICITY MECHANISMS IN THE FRAMEWORK OF OXIDATIVE STRESS, INFLAMMATION, AND EPIGENETIC CHANGES. WE ALSO REVIEWED ITS CORRELATION WITH RESPIRATORY DISEASES. IN ADDITION, WE REVIEWED BIOMARKERS RELATED TO PM-INDUCED RESPIRATORY DISEASES. THESE BIOMARKERS MIGHT BE USED FOR DISEASE PREDICTION AND EARLY DIAGNOSIS. WITH RECENT TREND OF USING GENOMIC ANALYSIS TOOLS IN THE FIELD OF TOXICOGENOMICS, RESPIRATORY DISEASE BIOMARKERS ASSOCIATED WITH PM WILL BE CONTINUOUSLY INVESTIGATED. EFFECTIVE BIOMARKERS DERIVED FROM EARLIER STUDIES AND FURTHER STUDIES MIGHT BE UTILIZED TO REDUCE RESPIRATORY DISEASES. 2017