1 6541 114 TRANSCRIPTOME ANALYSIS OF HUMAN PRIMARY ENDOTHELIAL CELLS (HUVEC) FROM UMBILICAL CORDS OF GESTATIONAL DIABETIC MOTHERS REVEALS CANDIDATE SITES FOR AN EPIGENETIC MODULATION OF SPECIFIC GENE EXPRESSION. WITHIN THE COMPLEX PATHOLOGICAL PICTURE ASSOCIATED TO DIABETES, HIGH GLUCOSE (HG) HAS "PER SE" EFFECTS ON CELLS AND TISSUES THAT INVOLVE EPIGENETIC REPROGRAMMING OF GENE EXPRESSION. IN FETAL TISSUES, EPIGENETIC CHANGES OCCUR GENOME-WIDE AND ARE BELIEVED TO INDUCE SPECIFIC LONG TERM EFFECTS. HUMAN UMBILICAL VEIN ENDOTHELIAL CELLS (HUVEC) OBTAINED AT DELIVERY FROM GESTATIONAL DIABETIC WOMEN WERE USED TO STUDY THE TRANSCRIPTOMIC EFFECTS OF CHRONIC HYPERGLYCEMIA IN FETAL VASCULAR CELLS USING AFFYMETRIX MICROARRAYS. IN SPITE OF THE SMALL NUMBER OF SAMPLES ANALYZED (N=6), GENES RELATED TO INSULIN SENSING AND EXTRACELLULAR MATRIX REORGANIZATION WERE FOUND SIGNIFICANTLY AFFECTED BY HG. QUANTITATIVE PCR ANALYSIS OF GENE PROMOTERS IDENTIFIED A SIGNIFICANT DIFFERENTIAL DNA METHYLATION IN TGFB2. USE OF EA.HY926 ENDOTHELIAL CELLS CONFIRMS DATA ON HUVEC. OUR STUDY CORROBORATES RECENT EVIDENCES SUGGESTING THAT EPIGENETIC REPROGRAMMING OF GENE EXPRESSION OCCURS WITH PERSISTENT HG AND PROVIDES A BACKGROUND FOR FUTURE INVESTIGATIONS ADDRESSING GENOMIC CONSEQUENCES OF CHRONIC HG. 2014 2 1269 33 CYTOSINE METHYLATION CHANGES IN ENHANCER REGIONS OF CORE PRO-FIBROTIC GENES CHARACTERIZE KIDNEY FIBROSIS DEVELOPMENT. BACKGROUND: ONE IN ELEVEN PEOPLE IS AFFECTED BY CHRONIC KIDNEY DISEASE, A CONDITION CHARACTERIZED BY KIDNEY FIBROSIS AND PROGRESSIVE LOSS OF KIDNEY FUNCTION. EPIDEMIOLOGICAL STUDIES INDICATE THAT ADVERSE INTRAUTERINE AND POSTNATAL ENVIRONMENTS HAVE A LONG-LASTING ROLE IN CHRONIC KIDNEY DISEASE DEVELOPMENT. EPIGENETIC INFORMATION REPRESENTS A PLAUSIBLE CARRIER FOR MEDIATING THIS PROGRAMMING EFFECT. HERE WE DEMONSTRATE THAT GENOME-WIDE CYTOSINE METHYLATION PATTERNS OF HEALTHY AND CHRONIC KIDNEY DISEASE TUBULE SAMPLES OBTAINED FROM PATIENTS SHOW SIGNIFICANT DIFFERENCES. RESULTS: WE IDENTIFY DIFFERENTIALLY METHYLATED REGIONS AND VALIDATE THESE IN A LARGE REPLICATION DATASET. THE DIFFERENTIALLY METHYLATED REGIONS ARE RARELY OBSERVED ON PROMOTERS, BUT MOSTLY OVERLAP WITH PUTATIVE ENHANCER REGIONS, AND THEY ARE ENRICHED IN CONSENSUS BINDING SEQUENCES FOR IMPORTANT RENAL TRANSCRIPTION FACTORS. THIS INDICATES THEIR IMPORTANCE IN GENE EXPRESSION REGULATION. A CORE SET OF GENES THAT ARE KNOWN TO BE RELATED TO KIDNEY FIBROSIS, INCLUDING GENES ENCODING COLLAGENS, SHOW CYTOSINE METHYLATION CHANGES CORRELATING WITH DOWNSTREAM TRANSCRIPT LEVELS. CONCLUSIONS: OUR REPORT RAISES THE POSSIBILITY THAT EPIGENETIC DYSREGULATION PLAYS A ROLE IN CHRONIC KIDNEY DISEASE DEVELOPMENT VIA INFLUENCING CORE PRO-FIBROTIC PATHWAYS AND CAN AID THE DEVELOPMENT OF NOVEL BIOMARKERS AND FUTURE THERAPEUTICS. 2013 3 3 39 "EPIGENOME-WIDE METHYLATION PROFILE OF CHRONIC KIDNEY DISEASE-DERIVED ARTERIAL DNA UNCOVERS NOVEL PATHWAYS IN DISEASE-ASSOCIATED CARDIOVASCULAR PATHOLOGY.". CHRONIC KIDNEY DISEASE (CKD) RELATED CARDIOVASCULAR DISEASE (CVD) IS CHARACTERIZED BY VASCULAR REMODELLING WITH WELL-ESTABLISHED STRUCTURAL AND FUNCTIONAL CHANGES IN THE VASCULAR WALL SUCH AS ARTERIAL STIFFNESS, MATRIX DEPOSITION, AND CALCIFICATION. THESE PHENOTYPIC CHANGES RESEMBLE PATHOLOGY SEEN IN AGEING, AND ARE LIKELY TO BE MEDIATED BY SUSTAINED ALTERATIONS IN GENE EXPRESSION, WHICH MAY BE CAUSED BY EPIGENETIC CHANGES SUCH AS TISSUE-SPECIFIC DNA METHYLATION. WE AIMED TO INVESTIGATE TISSUE SPECIFIC CHANGES IN DNA METHYLATION THAT OCCUR IN CKD-RELATED CVD. GENOME-WIDE DNA METHYLATION CHANGES WERE EXAMINED IN BISULPHITE CONVERTED GENOMIC DNA ISOLATED FROM THE VASCULAR MEDIA OF CKD AND HEALTHY ARTERIES. METHYLATION-SPECIFIC PCR WAS USED TO VALIDATE THE ARRAY DATA, AND THE ASSOCIATION BETWEEN DNA METHYLATION AND GENE AND PROTEIN EXPRESSION WAS EXAMINED. THE DNA METHYLATION AGE WAS COMPARED TO THE CHRONOLOGICAL AGE IN BOTH CASES AND CONTROLS. THREE HUNDRED AND NINETEEN DIFFERENTIALLY METHYLATED REGIONS (DMR) WERE IDENTIFIED SPREAD ACROSS THE GENOME. PATHWAY ANALYSIS REVEALED THAT DMRS ASSOCIATED WITH GENES WERE INVOLVED IN EMBRYONIC AND VASCULAR DEVELOPMENT, AND SIGNALLING PATHWAYS SUCH AS TGFBETA AND FGF. EXPRESSION OF TOP DIFFERENTIALLY METHYLATED GENE HOXA5 SHOWED A SIGNIFICANT NEGATIVE CORRELATION WITH DNA METHYLATION. INTERESTINGLY, DNA METHYLATION AGE AND CHRONOLOGICAL AGE WERE HIGHLY CORRELATED, BUT THERE WAS NO EVIDENCE OF ACCELERATED AGE-RELATED DNA METHYLATION IN THE ARTERIES OF CKD PATIENTS. IN CONCLUSION, WE DEMONSTRATED THAT DIFFERENTIAL DNA METHYLATION IN THE ARTERIAL TISSUE OF CKD PATIENTS REPRESENTS A POTENTIAL MEDIATOR OF ARTERIAL PATHOLOGY AND MAY BE USED TO UNCOVER NOVEL PATHWAYS IN THE GENESIS OF CKD-ASSOCIATED COMPLICATIONS. 2021 4 4292 31 MICRORNA PROFILES OF MATERNAL AND NEONATAL ENDOTHELIAL PROGENITOR CELLS IN PREECLAMPSIA. PREECLAMPSIA IS ASSOCIATED WITH AN INCREASED CARDIOVASCULAR MORBIDITY OF MOTHER AND OFFSPRING, THUS CONTRIBUTING TO A SUBSTANTIAL BURDEN IN WOMEN AND CHILDREN'S HEALTH. IT HAS BEEN PROVEN THAT ENDOTHELIAL PROGENITOR CELL (EPC) NUMBERS AND FUNCTIONAL CHARACTERISTICS ARE IMPAIRED IN CARDIOVASCULAR DISEASE AND PREECLAMPSIA, ALTHOUGH CAUSATIVE FACTORS FOR THE LATTER HAVE REMAINED ELUSIVE. MICRORNA (MIRNA) MODIFICATIONS ARE A POTENTIAL MECHANISM THROUGH WHICH EXPOSURE TO AN ALTERED ENVIRONMENT TRANSLATES INTO THE DEVELOPMENT OF CHRONIC DISEASE. IN THIS STUDY, WE EXAMINED WHETHER DEVELOPMENT OF PREECLAMPSIA CORRESPONDS TO ALTERATIONS OF MIRNAS IN MATERNAL- AND CORD-BLOOD-DERIVED EPC. TO TEST THIS END, WE ANALYZED MATERNAL AND NEONATAL MIRNAS VIA RNA SEQUENCING FROM ENDOTHELIAL CELLS OF PREECLAMPTIC AND HEALTHY CONTROLS IN DIFFERENT CELL CULTURE PASSAGES. WE WERE ABLE TO DEMONSTRATE DIFFERENTIALLY REPRESENTED MIRNAS IN ALL GROUPS. HSA-MIR-1270 SHOWED SIGNIFICANTLY DIFFERENT LEVELS IN CORD BLOOD EPC FROM PREECLAMPSIA VERSUS CONTROL AND WAS NEGATIVELY CORRELATED WITH MRNA LEVELS OF ITS PREDICTED TARGETS ANGPTL7 AND TFRC. TRANSFECTION WITH AN HSA-MIR-1270 INHIBITOR DECREASED THE TUBE FORMATION CAPACITY AND CHEMOTACTIC MOTILITY BUT DID NOT CHANGE PROLIFERATION IN VITRO. TARGET PREDICTIONS AND GENE SET ENRICHMENT ANALYSES IDENTIFIED ALTERNATIVE SPLICING AS A SIGNIFICANTLY ENRICHED PATHWAY FOR HSA-MIR-1270. THE TOP MIRNAS IN THREE OTHER GROUPS WERE PREDICTED TO TARGET TRANSCRIPTIONAL AND DEVELOPMENTAL PATHWAYS. HERE, WE SHOWED FOR THE FIRST TIME SIGNIFICANTLY DIFFERENT LEVELS OF MIRNAS AND DIFFERENTLY REPRESENTED MRNA LEVELS OF PREDICTED TARGET GENES IN EPC DERIVED FROM PREECLAMPSIA. UNDERSTANDING THE EFFECTS OF PREECLAMPSIA ON THE EPIGENETIC MECHANISMS OF EPC WILL BE CRUCIAL AND MAY PROVIDE INITIAL INSIGHTS FOR FURTHER EVALUATION OF THE BENEFITS OF THERAPIES TARGETING THIS CELL POPULATION. 2021 5 2873 26 FUNCTIONAL METHYLOME ANALYSIS OF HUMAN DIABETIC KIDNEY DISEASE. IN PATIENTS WITH DIABETES MELLITUS, POOR METABOLIC CONTROL HAS A LONG-LASTING IMPACT ON KIDNEY DISEASE DEVELOPMENT. EPIGENETIC CHANGES, INCLUDING CYTOSINE METHYLATION, HAVE BEEN PROPOSED AS POTENTIAL MEDIATORS OF THE LONG-LASTING EFFECT OF ADVERSE METABOLIC EVENTS. OUR UNDERSTANDING OF THE PRESENCE AND CONTRIBUTION OF METHYLATION CHANGES TO DISEASE DEVELOPMENT IS LIMITED BECAUSE OF THE LACK OF COMPREHENSIVE BASE-RESOLUTION METHYLOME INFORMATION OF HUMAN KIDNEY TISSUE SAMPLES AND SITE-SPECIFIC METHYLATION EDITING. BASE RESOLUTION, WHOLE-GENOME BISULFITE SEQUENCING METHYLOME MAPS OF HUMAN DIABETIC KIDNEY DISEASE (DKD) TUBULE SAMPLES, AND ASSOCIATED GENE EXPRESSION MEASURED BY RNA SEQUENCING HIGHLIGHTED WIDESPREAD METHYLATION CHANGES IN DKD. PATHWAY ANALYSIS HIGHLIGHTED COORDINATED (METHYLATION AND GENE EXPRESSION) CHANGES IN IMMUNE SIGNALING, INCLUDING TUMOR NECROSIS FACTOR ALPHA (TNF). CHANGES IN TNF METHYLATION CORRELATED WITH KIDNEY FUNCTION DECLINE. DCAS9-TET1-BASED LOWERING OF THE CYTOSINE METHYLATION LEVEL OF THE TNF DIFFERENTIALLY METHYLATED REGION RESULTED IN AN INCREASE IN THE TNF TRANSCRIPT LEVEL, INDICATING THAT METHYLATION OF THIS LOCUS PLAYS AN IMPORTANT ROLE IN CONTROLLING TNF EXPRESSION. INCREASING THE TNF LEVEL IN DIABETIC MICE INCREASED DISEASE SEVERITY, SUCH AS ALBUMINURIA. IN SUMMARY, OUR RESULTS INDICATE WIDESPREAD METHYLATION DIFFERENCES IN DKD KIDNEYS AND HIGHLIGHTS EPIGENETIC CHANGES IN THE TNF LOCUS AND ITS CONTRIBUTION TO THE DEVELOPMENT OF NEPHROPATHY IN PATIENTS WITH DIABETES MELLITUS. 2019 6 1794 31 EFFECT OF DIABETES STATUS AND HYPERGLYCEMIA ON GLOBAL DNA METHYLATION AND HYDROXYMETHYLATION. TYPE 2 DIABETES MELLITUS (T2DM) IS CHARACTERIZED BY OXIDATIVE STRESS THAT COULD LEAD TO CHRONIC MICRO- AND MACROVASCULAR COMPLICATIONS. WE HYPOTHESIZED THAT SOME OF THE TARGET ORGAN DAMAGE IS MEDIATED BY OXIDATIVE ALTERATIONS IN EPIGENETIC MECHANISMS INVOLVING DNA METHYLATION (5MC) AND DNA HYDROXYMETHYLATION (5HMC). WE ANALYZED GLOBAL DNA METHYLATION AND HYDROXYMETHYLATION IN PERIPHERAL BLOOD CELLS IN WELL-CONTROLLED AND POORLY CONTROLLED PATIENTS WITH T2DM AND COMPARED THEM WITH HEALTHY CONTROLS. WE ALSO ANALYZED MICROARRAYS OF DNA METHYLATION AND GENE EXPRESSION OF OTHER IMPORTANT TISSUES IN THE CONTEXT OF DIABETES FROM THE GEO DATABASE REPOSITORY AND THEN COMPARED THESE RESULTS WITH OUR EXPERIMENTAL GENE EXPRESSION DATA. DNA METHYLATION AND, MORE IMPORTANTLY, DNA HYDROXYMETHYLATION LEVELS WERE INCREASED IN POORLY CONTROLLED PATIENTS COMPARED TO WELL-CONTROLLED AND HEALTHY INDIVIDUALS. BOTH 5MC AND 5HMC MEASUREMENTS WERE CORRELATED WITH THE PERCENTAGE OF GLYCATED HEMOGLOBIN, INDICATING A DIRECT IMPACT OF HYPERGLYCEMIA ON CHANGES OVER THE EPIGENOME. THE ANALYSIS OF METHYLATION MICROARRAYS WAS CONCORDANT, AND 5MC LEVELS WERE INCREASED IN THE PERIPHERAL BLOOD OF T2DM PATIENTS. HOWEVER, THE DNA METHYLATION LEVELS WERE THE OPPOSITE OF THOSE IN OTHER TISSUES, SUCH AS THE PANCREAS, ADIPOSE TISSUE AND SKELETAL MUSCLE. WE HYPOTHESIZE THAT A PROCESS OF DNA OXIDATION ASSOCIATED WITH HYPERGLYCEMIA MAY EXPLAIN THE DNA DEMETHYLATION IN WHICH THE ACTIVITY OF TEN-ELEVEN TRANSLOCATION (TET) PROTEINS IS NOT SUFFICIENT TO COMPLETE THE PROCESS. HIGH LEVELS OF GLUCOSE LEAD TO CELLULAR OXIDATION, WHICH TRIGGERS THE PROCESS OF DNA DEMETHYLATION AIDED BY TET ENZYMES, RESULTING IN EPIGENETIC DYSREGULATION OF THE DAMAGED TISSUES. 2017 7 6431 40 THE USE OF TARGETED NEXT GENERATION SEQUENCING TO EXPLORE CANDIDATE REGULATORS OF TGF-BETA1'S IMPACT ON KIDNEY CELLS. AIMS/HYPOTHESIS: TRANSFORMING GROWTH FACTOR-BETA (TGF-BETA1) PLAYS AN IMPORTANT REGULATORY ROLE IN THE PROGRESSION OF CHRONIC KIDNEY FAILURE. FURTHER, DAMAGE TO KIDNEY GLOMERULAR MESANGIAL CELLS IS CENTRAL TO THE PROGRESSION OF DIABETIC NEPHROPATHY. THE AIM OF THIS STUDY WAS TO EXPLORE THE GENETIC ASSOCIATIONS BETWEEN MRNA, MICRORNA, AND EPIGENETICS IN MESANGIAL CELLS IN RESPONSE TO TGF-BETA1. METHODS: THE REGULATORY EFFECTS OF TGF-BETA1 ON MESANGIAL CELLS WERE INVESTIGATED AT DIFFERENT MOLECULAR LEVELS BY TREATING MESANGIAL CELLS WITH TGF-BETA1 FOR 3 DAYS FOLLOWED BY GENOME-WIDE MIRNA, RNA, DNA METHYLATION, AND H3K27ME3 EXPRESSION PROFILING USING NEXT GENERATION SEQUENCING (NGS). RESULTS: OUR RESULTS PROVIDE THE FIRST COMPREHENSIVE, COMPUTATIONALLY INTEGRATED REPORT OF RNA-SEQ, MIRNA-SEQ, AND EPIGENOMIC ANALYSES ACROSS ALL GENETIC VARIATIONS, CONFIRMING THE OCCURRENCE OF DNA METHYLATION AND H3K27ME3 IN RESPONSE TO TGF-BETA1. OUR FINDINGS SHOW THAT THE EXPRESSION OF KLF7 AND GJA4 ARE INVOLVED IN TGF-BETA1 REGULATED DNA METHYLATION. OUR DATA ALSO PROVIDE EVIDENCE OF THE ASSOCIATION BETWEEN EPIGENETIC CHANGES AND THE EXPRESSION OF GENES CLOSELY RELATED TO TGF-BETA1 REGULATION. CONCLUSION: THIS STUDY HAS ADVANCED OUR CURRENT KNOWLEDGE OF MECHANISMS THAT CONTRIBUTE TO THE EXPRESSION OF TGF-BETA1-REGULATED GENES INVOLVED IN THE PATHOGENESIS OF KIDNEY DISEASE. THE MOLECULAR UNDERPINNINGS OF TGF-BETA1 STIMULATION OF KIDNEY CELLS WAS DETERMINED, THEREBY PROVIDING A ROBUST PLATFORM FOR FURTHER TARGET EXPLORATION. 2018 8 6564 33 TRANSIENT EXPOSURE TO ELEVATED GLUCOSE LEVELS CAUSES PERSISTENT CHANGES IN DERMAL MICROVASCULAR ENDOTHELIAL CELL RESPONSES TO INJURY. BACKGROUND: THE PURPOSE OF THIS STUDY WAS TO DETERMINE WHETHER ELEVATED GLUCOSE CAN INDUCE A DERMAL MICROVASCULAR ENDOTHELIAL CELL METABOLIC MEMORY, THUS AFFECTING ANGIOGENESIS IN THE REPAIR PROCESS OF MAMMALIAN CUTANEOUS WOUND. WE HYPOTHESIZED THAT TRANSIENT ELEVATED GLUCOSE LEVELS CAUSE SUSTAINED ALTERATION OF ENDOTHELIAL CELL RESPONSES TO INJURY AND PERSISTENT EPIGENETIC CHANGES IN GENE EXPRESSION. METHODS: HUMAN DERMAL MICROVASCULAR ENDOTHELIAL CELLS WERE EXPOSED TO EXPERIMENTAL CONDITIONS WITH OR WITHOUT 30 MM D-GLUCOSE. THE CONTROL GROUP WAS MAINTAINED AT 5 MM D-GLUCOSE; WHILE IN THE TRANSIENT GLUCOSE GROUP, AFTER BEING EXPOSED TO 30 MM D-GLUCOSE FOR TWO DAYS, THEN BEING PUT UNDER THE CONTROL CONDITIONS DURING THE EXPERIMENT. BESIDES, IN THE WHOLE PROCESS OF THE EXPERIMENT, THE CHRONIC GLUCOSE GROUP WAS KEPT IN THE CONDITION WITH 30 MM D-GLUCOSE. PROLIFERATION, MIGRATION, TUBE FORMATION, GENE EXPRESSION AND HISTONE METHYLATION WERE ASSESSED FOR INDIVIDUAL CONDITIONS. RESULTS: TRANSIENT ELEVATED GLUCOSE CAUSED SUSTAINED EFFECTS ON ENDOTHELIAL CELL MIGRATION, TUBE FORMATION AND TIMP3 GENE EXPRESSION. THE EFFECTS ON TIMP3 EXPRESSION WERE ASSOCIATED WITH PERSISTENT CHANGES IN HISTONE MODIFICATION AT THE 5' END OF THE TIMP3 GENE, SUGGESTING AN EPIGENETIC EFFECT. CONCLUSIONS: HYPERGLYCEMIA INDUCED METABOLIC MEMORY COULD PROMOTE THE REGULATION OF TIMP3, AND IT CAN BE USED AS A POSSIBLE INNOVATIVE MOLECULAR TARGET FOR THERAPEUTIC INTERVENTION IN THE TREATMENT OF CHRONIC NON-HEALING DIABETIC WOUNDS. 2021 9 1583 35 DNA METHYLATION PROFILES OF BLOOD CELLS ARE DISTINCT BETWEEN EARLY-ONSET OBESE AND CONTROL INDIVIDUALS. OBESITY IS A HIGHLY PREVALENT, CHRONIC DISORDER THAT HAS BEEN INCREASING IN INCIDENCE IN YOUNG PATIENTS. BOTH EPIGENETIC AND GENETIC ABERRATIONS MAY PLAY A ROLE IN THE PATHOGENESIS OF OBESITY. THEREFORE, IN-DEPTH EPIGENOMIC AND GENOMIC ANALYSES WILL ADVANCE OUR UNDERSTANDING OF THE DETAILED MOLECULAR MECHANISMS UNDERLYING OBESITY AND AID IN THE SELECTION OF POTENTIAL BIOMARKERS FOR OBESITY IN YOUTH. HERE, WE PERFORMED MICROARRAY-BASED DNA METHYLATION AND GENE EXPRESSION PROFILING OF PERIPHERAL WHITE BLOOD CELLS OBTAINED FROM SIX YOUNG, OBESE INDIVIDUALS AND SIX HEALTHY CONTROLS. WE OBSERVED THAT THE HIERARCHICAL CLUSTERING OF DNA METHYLATION, BUT NOT GENE EXPRESSION, CLEARLY SEGREGATES THE OBESE INDIVIDUALS FROM THE CONTROLS, SUGGESTING THAT THE METABOLIC DISTURBANCE THAT OCCURS AS A RESULT OF OBESITY AT A YOUNG AGE MAY AFFECT THE DNA METHYLATION OF PERIPHERAL BLOOD CELLS WITHOUT ACCOMPANYING TRANSCRIPTIONAL CHANGES. TO EXAMINE THE GENOME-WIDE DIFFERENCES IN THE DNA METHYLATION PROFILES OF YOUNG OBESE AND CONTROL INDIVIDUALS, WE IDENTIFIED DIFFERENTIALLY METHYLATED CPG SITES AND INVESTIGATED THEIR GENOMIC AND EPIGENOMIC CONTEXTS. THE ABERRANT DNA METHYLATION PATTERNS IN OBESE INDIVIDUALS CAN BE SUMMARIZED AS RELATIVE GAINS AND LOSSES OF DNA METHYLATION IN GENE PROMOTERS AND GENE BODIES, RESPECTIVELY. WE ALSO OBSERVED THAT THE CPG ISLANDS OF OBESE INDIVIDUALS ARE MORE SUSCEPTIBLE TO DNA METHYLATION COMPARED TO CONTROLS. OUR PILOT STUDY SUGGESTS THAT THE GENOME-WIDE ABERRANT DNA METHYLATION PATTERNS OF OBESE INDIVIDUALS MAY ADVANCE NOT ONLY OUR UNDERSTANDING OF THE EPIGENOMIC PATHOGENESIS BUT ALSO EARLY SCREENING OF OBESITY IN YOUTH. 2017 10 5305 34 PROTEOMICS ANALYSIS OF HUMAN OBESITY REVEALS THE EPIGENETIC FACTOR HDAC4 AS A POTENTIAL TARGET FOR OBESITY. SEDENTARY LIFESTYLE AND EXCESSIVE ENERGY INTAKE ARE PROMINENT CONTRIBUTORS TO OBESITY; A MAJOR RISK FACTORS FOR THE DEVELOPMENT OF INSULIN RESISTANCE, TYPE 2 DIABETES AND CARDIOVASCULAR DISEASES. ELUCIDATING THE MOLECULAR MECHANISMS UNDERLYING THESE CHRONIC CONDITIONS IS OF RELEVANT IMPORTANCE AS IT MIGHT LEAD TO THE IDENTIFICATION OF NOVEL ANTI-OBESITY TARGETS. THE PURPOSE OF THE CURRENT STUDY IS TO INVESTIGATE DIFFERENTIALLY EXPRESSED PROTEINS BETWEEN LEAN AND OBESE SUBJECTS THROUGH A SHOT-GUN QUANTITATIVE PROTEOMICS APPROACH USING PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMCS) EXTRACTS AS WELL AS POTENTIAL MODULATION OF THOSE PROTEINS BY PHYSICAL EXERCISE. USING THIS APPROACH, A TOTAL OF 47 PROTEINS SHOWED AT LEAST 1.5 FOLD CHANGE BETWEEN LEAN AND OBESE SUBJECTS. IN OBESE, THE PROTEOMIC PROFILING BEFORE AND AFTER 3 MONTHS OF PHYSICAL EXERCISE SHOWED DIFFERENTIAL EXPRESSION OF 38 PROTEINS. THROMBOSPONDIN 1 (TSP1) WAS AMONG THE PROTEINS THAT WERE UPREGULATED IN OBESE SUBJECTS AND THEN DECREASED BY PHYSICAL EXERCISE. CONVERSELY, THE HISTONE DEACETYLASE 4 (HDAC4) WAS DOWNREGULATED IN OBESE SUBJECTS AND THEN INDUCED BY PHYSICAL EXERCISE. THE PROTEOMIC DATA WAS FURTHER VALIDATED BY QRT-PCR, WESTERN BLOT AND IMMUNOHISTOCHEMISTRY IN BOTH PBMCS AND ADIPOSE TISSUE. WE ALSO SHOWED THAT HDAC4 LEVELS CORRELATED POSITIVELY WITH MAXIMUM OXYGEN CONSUMPTION (VO2 MAX) BUT NEGATIVELY WITH BODY MASS INDEX, PERCENT BODY FAT, AND THE INFLAMMATORY CHEMOKINE RANTES. IN FUNCTIONAL ASSAYS, OUR DATA INDICATED THAT ECTOPIC EXPRESSION OF HDAC4 SIGNIFICANTLY IMPAIRED TNF-ALPHA-DEPENDENT ACTIVATION OF NF-KAPPAB, ESTABLISHING THUS A LINK BETWEEN HDAC4 AND REGULATION OF THE IMMUNE SYSTEM. TOGETHER, THE EXPRESSION PATTERN OF HDAC4 IN OBESE SUBJECTS BEFORE AND AFTER PHYSICAL EXERCISE, ITS CORRELATION WITH VARIOUS PHYSICAL, CLINICAL AND METABOLIC PARAMETERS ALONG WITH ITS INHIBITORY EFFECT ON NF-KAPPAB ARE SUGGESTIVE OF A PROTECTIVE ROLE OF HDAC4 AGAINST OBESITY. HDAC4 COULD THEREFORE REPRESENT A POTENTIAL THERAPEUTIC TARGET FOR THE CONTROL AND MANAGEMENT OF OBESITY AND PRESUMABLY INSULIN RESISTANCE. 2013 11 5067 29 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 12 457 30 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 13 2920 37 GENE-SET ANALYSIS IS SEVERELY BIASED WHEN APPLIED TO GENOME-WIDE METHYLATION DATA. MOTIVATION: DNA METHYLATION IS AN EPIGENETIC MARK THAT CAN STABLY REPRESS GENE EXPRESSION. BECAUSE OF ITS BIOLOGICAL AND CLINICAL SIGNIFICANCE, SEVERAL METHODS HAVE BEEN DEVELOPED TO COMPARE GENOME-WIDE PATTERNS OF METHYLATION BETWEEN GROUPS OF SAMPLES. THE APPLICATION OF GENE SET ANALYSIS TO IDENTIFY RELEVANT GROUPS OF GENES THAT ARE ENRICHED FOR DIFFERENTIALLY METHYLATED GENES IS OFTEN A MAJOR COMPONENT OF THE ANALYSIS OF THESE DATA. THIS CAN BE USED, FOR EXAMPLE, TO IDENTIFY PROCESSES OR PATHWAYS THAT ARE PERTURBED IN DISEASE DEVELOPMENT. WE SHOW THAT GENE-SET ANALYSIS, AS IT IS TYPICALLY APPLIED TO GENOME-WIDE METHYLATION ASSAYS, IS SEVERELY BIASED AS A RESULT OF DIFFERENCES IN THE NUMBERS OF CPG SITES ASSOCIATED WITH DIFFERENT CLASSES OF GENES AND GENE PROMOTERS. RESULTS: WE DEMONSTRATE THIS BIAS USING PUBLISHED DATA FROM A STUDY OF DIFFERENTIAL CPG ISLAND METHYLATION IN LUNG CANCER AND A DATASET WE GENERATED TO STUDY METHYLATION CHANGES IN PATIENTS WITH LONG-STANDING ULCERATIVE COLITIS. WE SHOW THAT SEVERAL OF THE GENE SETS THAT SEEM ENRICHED WOULD ALSO BE IDENTIFIED WITH RANDOMIZED DATA. WE SUGGEST TWO EXISTING APPROACHES THAT CAN BE ADAPTED TO CORRECT THE BIAS. ACCOUNTING FOR THE BIAS IN THE LUNG CANCER AND ULCERATIVE COLITIS DATASETS PROVIDES NOVEL BIOLOGICAL INSIGHTS INTO THE ROLE OF METHYLATION IN CANCER DEVELOPMENT AND CHRONIC INFLAMMATION, RESPECTIVELY. OUR RESULTS HAVE SIGNIFICANT IMPLICATIONS FOR MANY PREVIOUS GENOME-WIDE METHYLATION STUDIES THAT HAVE DRAWN CONCLUSIONS ON THE BASIS OF SUCH STRONGLY BIASED ANALYSIS. CONTACT: CATHAL.SEOIGHE@NUIGALWAY.IE SUPPLEMENTARY INFORMATION: SUPPLEMENTARY DATA ARE AVAILABLE AT BIOINFORMATICS ONLINE. 2013 14 3292 38 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 15 1503 29 DNA METHYLATION AND GENE EXPRESSION DIFFERENCES IN CHILDREN CONCEIVED IN VITRO OR IN VIVO. EPIDEMIOLOGICAL DATA INDICATE THAT CHILDREN CONCEIVED IN VITRO HAVE A GREATER RELATIVE RISK OF LOW BIRTH-WEIGHT, MAJOR AND MINOR BIRTH DEFECTS, AND RARE DISORDERS INVOLVING IMPRINTED GENES, SUGGESTING THAT EPIGENETIC CHANGES MAY BE ASSOCIATED WITH ASSISTED REPRODUCTION. WE EXAMINED DNA METHYLATION AT MORE THAN 700 GENES (1536 CPG SITES) IN PLACENTA AND CORD BLOOD AND MEASURED GENE EXPRESSION LEVELS OF A SUBSET OF GENES THAT DIFFERED IN METHYLATION LEVELS BETWEEN CHILDREN CONCEIVED IN VITRO VERSUS IN VIVO. OUR RESULTS SUGGEST THAT IN VITRO CONCEPTION IS ASSOCIATED WITH LOWER MEAN METHYLATION AT CPG SITES IN PLACENTA AND HIGHER MEAN METHYLATION AT CPG SITES IN CORD BLOOD. WE ALSO FIND THAT IN VITRO CONCEPTION-ASSOCIATED DNA METHYLATION DIFFERENCES ARE ASSOCIATED WITH GENE EXPRESSION DIFFERENCES AT BOTH IMPRINTED AND NON-IMPRINTED GENES. THE RANGE OF INTER-INDIVIDUAL VARIATION IN GENE EXPRESSION OF THE IN VITRO AND IN VIVO GROUPS OVERLAPS SUBSTANTIALLY BUT SOME INDIVIDUALS FROM THE IN VITRO GROUP DIFFER FROM THE IN VIVO GROUP MEAN BY MORE THAN TWO STANDARD DEVIATIONS. SEVERAL OF THE GENES WHOSE EXPRESSION DIFFERS BETWEEN THE TWO GROUPS HAVE BEEN IMPLICATED IN CHRONIC METABOLIC DISORDERS, SUCH AS OBESITY AND TYPE II DIABETES. THESE FINDINGS SUGGEST THAT THERE MAY BE EPIGENETIC DIFFERENCES IN THE GAMETES OR EARLY EMBRYOS DERIVED FROM COUPLES UNDERGOING TREATMENT FOR INFERTILITY. ALTERNATIVELY, ASSISTED REPRODUCTION TECHNOLOGY MAY HAVE AN EFFECT ON GLOBAL PATTERNS OF DNA METHYLATION AND GENE EXPRESSION. IN EITHER CASE, THESE DIFFERENCES OR CHANGES MAY AFFECT LONG-TERM PATTERNS OF GENE EXPRESSION. 2009 16 3836 28 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 17 904 37 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 18 416 32 ANALYSIS OF THE DYNAMIC ABERRANT LANDSCAPE OF DNA METHYLATION AND GENE EXPRESSION DURING ARSENIC-INDUCED CELL TRANSFORMATION. INORGANIC ARSENIC IS A WELL-KNOWN CARCINOGEN ASSOCIATED WITH SEVERAL TYPES OF CANCER, BUT THE MECHANISMS INVOLVED IN ARSENIC-INDUCED CARCINOGENESIS ARE NOT FULLY UNDERSTOOD. RECENT EVIDENCE POINTS TO EPIGENETIC DYSREGULATION AS AN IMPORTANT MECHANISM IN THIS PROCESS; HOWEVER, THE EFFECTS OF EPIGENETIC ALTERATIONS IN GENE EXPRESSION HAVE NOT BEEN EXPLORED IN DEPTH. USING MICROARRAY DATA AND APPLYING A MULTIVARIATE CLUSTERING ANALYSIS IN A GAUSSIAN MIXTURE MODEL, WE DESCRIBE THE ALTERATIONS IN DNA METHYLATION AROUND THE PROMOTER REGION AND THE IMPACT ON GENE EXPRESSION IN HACAT CELLS DURING THE TRANSFORMATION PROCESS CAUSED BY CHRONIC EXPOSURE TO ARSENIC. USING THIS CLUSTERING APPROACH, THE GENES WERE GROUPED ACCORDING TO THEIR METHYLATION AND EXPRESSION STATUS IN THE EPIGENETIC LANDSCAPE, AND THE CHANGES THAT OCCURRED DURING THE CELLULAR TRANSFORMATION WERE IDENTIFIED ADEQUATELY. THUS, WE PRESENT A VALUABLE METHOD FOR IDENTIFYING EPIGENOMIC DYSREGULATION. 2019 19 2483 30 EPIGENETIC VARIATION AND HUMAN DISEASE. CYTOSINE GUANINE DINUCLEOTIDE (CPG) ISLAND METHYLATION IS A KNOWN MECHANISM OF EPIGENETIC INHERITANCE IN POSTMEIOTIC CELLS. THROUGH ASSOCIATED CHROMATIN CHANGES AND SILENCING, SUCH EPIGENETIC STATES CAN INFLUENCE CELLULAR PHYSIOLOGY AND AFFECT DISEASE RISK AND SEVERITY. OUR STUDIES OF CPG ISLAND METHYLATION IN NORMAL COLORECTAL MUCOSA REVEALED PROGRESSIVE AGE-RELATED INCREASES AT MULTIPLE GENE LOCI, SUGGESTING GENOME-WIDE MOLECULAR ALTERATIONS WITH POTENTIAL TO SILENCE GENE EXPRESSION. HOWEVER, THERE WAS CONSIDERABLE VARIATION IN THE DEGREE OF METHYLATION AMONG INDIVIDUALS OF COMPARABLE AGES. SUCH VARIATION COULD BE RELATED TO GENETIC FACTORS, LIFESTYLE, OR ENVIRONMENTAL EXPOSURES. STUDIES IN ULCERATIVE COLITIS AND HEPATOCELLULAR CIRRHOSIS AND NEOPLASIA REVEALED THAT CHRONIC INFLAMMATORY STATES ARE ACCOMPANIED BY MARKED INCREASES IN CPG ISLAND METHYLATION IN NORMAL-APPEARING TISSUES, CONFIRMING THE HYPOTHESIS THAT PROINFLAMMATORY EXPOSURES COULD ACCOUNT FOR PART OF THE EPIGENETIC VARIATION IN HUMAN POPULATIONS. PRELIMINARY DATA ALSO SUGGEST POTENTIAL INFLUENCES OF LIFESTYLE AND EXPOSURE FACTORS ON CPG ISLAND METHYLATION. IT IS SUGGESTED THAT EPIGENETIC VARIATION RELATED TO AGING, LIFESTYLE, EXPOSURES AND POSSIBLY GENETIC FACTORS, IS ONE OF THE MODULATORS OF ACQUIRED, AGE-RELATED HUMAN DISEASES, INCLUDING NEOPLASIA. 2002 20 287 37 AGING AND CHRONIC SUN EXPOSURE CAUSE DISTINCT EPIGENETIC CHANGES IN HUMAN SKIN. EPIGENETIC CHANGES ARE WIDELY CONSIDERED TO PLAY AN IMPORTANT ROLE IN AGING, BUT EXPERIMENTAL EVIDENCE TO SUPPORT THIS HYPOTHESIS HAS BEEN SCARCE. WE HAVE USED ARRAY-BASED ANALYSIS TO DETERMINE GENOME-SCALE DNA METHYLATION PATTERNS FROM HUMAN SKIN SAMPLES AND TO INVESTIGATE THE EFFECTS OF AGING, CHRONIC SUN EXPOSURE, AND TISSUE VARIATION. OUR RESULTS REVEAL A HIGH DEGREE OF TISSUE SPECIFICITY IN THE METHYLATION PATTERNS AND ALSO SHOWED VERY LITTLE INTERINDIVIDUAL VARIATION WITHIN TISSUES. DATA STRATIFICATION BY AGE REVEALED THAT DNA FROM OLDER INDIVIDUALS WAS CHARACTERIZED BY A SPECIFIC HYPERMETHYLATION PATTERN AFFECTING LESS THAN 1% OF THE MARKERS ANALYZED. INTERESTINGLY, STRATIFICATION BY SUN EXPOSURE PRODUCED A FUNDAMENTALLY DIFFERENT PATTERN WITH A SIGNIFICANT TREND TOWARDS HYPOMETHYLATION. OUR RESULTS THUS IDENTIFY DEFINED AGE-RELATED DNA METHYLATION CHANGES AND SUGGEST THAT THESE ALTERATIONS MIGHT CONTRIBUTE TO THE PHENOTYPIC CHANGES ASSOCIATED WITH SKIN AGING. 2010