1 356 127 ALTERING A HISTONE H3K4 METHYLATION PATHWAY IN GLOMERULAR PODOCYTES PROMOTES A CHRONIC DISEASE PHENOTYPE. METHYLATION OF SPECIFIC LYSINE RESIDUES IN CORE HISTONE PROTEINS IS ESSENTIAL FOR EMBRYONIC DEVELOPMENT AND CAN IMPART ACTIVE AND INACTIVE EPIGENETIC MARKS ON CHROMATIN DOMAINS. THE UBIQUITOUS NUCLEAR PROTEIN PTIP IS ENCODED BY THE PAXIP1 GENE AND IS AN ESSENTIAL COMPONENT OF A HISTONE H3 LYSINE 4 (H3K4) METHYLTRANSFERASE COMPLEX CONSERVED IN METAZOANS. IN ORDER TO DETERMINE IF PTIP AND ITS ASSOCIATED COMPLEXES ARE NECESSARY FOR MAINTAINING STABLE GENE EXPRESSION PATTERNS IN A TERMINALLY DIFFERENTIATED, NON-DIVIDING CELL, WE CONDITIONALLY DELETED PTIP IN GLOMERULAR PODOCYTES IN MICE. RENAL DEVELOPMENT AND FUNCTION WERE NOT IMPAIRED IN YOUNG MICE. HOWEVER, OLDER ANIMALS PROGRESSIVELY EXHIBITED PROTEINURIA AND PODOCYTE ULTRA STRUCTURAL DEFECTS SIMILAR TO CHRONIC GLOMERULAR DISEASE. LOSS OF PTIP RESULTED IN SUBTLE CHANGES IN GENE EXPRESSION PATTERNS PRIOR TO THE ONSET OF A RENAL DISEASE PHENOTYPE. CHROMATIN IMMUNOPRECIPITATION SHOWED A LOSS OF PTIP BINDING AND LOWER H3K4 METHYLATION AT THE NTRK3 (NEUROTROPHIC TYROSINE KINASE RECEPTOR, TYPE 3) LOCUS, WHOSE EXPRESSION WAS SIGNIFICANTLY REDUCED AND WHOSE FUNCTION MAY BE ESSENTIAL FOR PODOCYTE FOOT PROCESS PATTERNING. THESE DATA DEMONSTRATE THAT ALTERATIONS OR MUTATIONS IN AN EPIGENETIC REGULATORY PATHWAY CAN ALTER THE PHENOTYPES OF DIFFERENTIATED CELLS AND LEAD TO A CHRONIC DISEASE STATE. 2010 2 5403 54 REGENERATION AFTER ACUTE KIDNEY INJURY REQUIRES PTIP-MEDIATED EPIGENETIC MODIFICATIONS. A TERMINALLY DIFFERENTIATED CELLULAR PHENOTYPE IS THOUGHT TO BE MAINTAINED, AT LEAST IN PART, BY BOTH ACTIVE AND REPRESSIVE HISTONE MARKS. HOWEVER, IT IS UNCLEAR WHETHER REGENERATING CELLS AFTER INJURY NEED TO REPLICATE SUCH EPIGENETIC MARKS TO RECOVER. TO TEST WHETHER RENAL EPITHELIAL CELL REGENERATION IS DEPENDENT ON HISTONE H3K4 METHYLATION, WE GENERATED A MOUSE MODEL THAT DELETED THE PAXIP1 GENE IN MATURE RENAL PROXIMAL TUBULES. PAXIP1 ENCODES PTIP, AN ESSENTIAL PROTEIN IN THE MLL3/4 HISTONE H3K4 METHYLTRANSFERASE COMPLEX. MICE WITH PTIP DELETIONS IN THE ADULT KIDNEY PROXIMAL TUBULES WERE VIABLE AND FERTILE. UPON ACUTE KIDNEY INJURY, SUCH MICE FAILED TO REGENERATE DAMAGED TUBULES, LEADING TO SCARRING AND INTERSTITIAL FIBROSIS. THE INABILITY TO REPAIR DAMAGE WAS LIKELY DUE TO A FAILURE TO REENTER MITOSIS AND REACTIVATE REGULATORY GENES SUCH AS SOX9. PTIP DELETION REDUCED HISTONE H3K4 METHYLATION IN UNINJURED ADULT KIDNEYS BUT DID NOT SIGNIFICANTLY AFFECT FUNCTION OR THE EXPRESSION OF EPITHELIAL SPECIFIC MARKERS. STRIKINGLY, CELL LINEAGE TRACING REVEALED THAT SURVIVING PTIP MUTANT CELLS COULD ALTER THEIR PHENOTYPE AND LOSE EPITHELIAL MARKERS. THESE DATA DEMONSTRATE THAT PTIP AND ASSOCIATED MLL3/4-MEDIATED HISTONE METHYLATION ARE NEEDED FOR REGENERATING PROXIMAL TUBULES AND TO MAINTAIN OR REESTABLISH THE CELLULAR EPITHELIAL PHENOTYPE. 2020 3 2055 33 EPIGENETIC CONTROL DURING LYMPHOID DEVELOPMENT AND IMMUNE RESPONSES: ABERRANT REGULATION, VIRUSES, AND CANCER. METHYLATION OF CYTOSINES CONTROLS A NUMBER OF BIOLOGIC PROCESSES SUCH AS IMPRINTING AND X CHROMOSOMAL INACTIVATION. DNA HYPERMETHYLATION IS CLOSELY ASSOCIATED WITH TRANSCRIPTIONAL SILENCING, WHILE DNA HYPOMETHYLATION IS ASSOCIATED WITH TRANSCRIPTIONAL ACTIVATION. HYPOACETYLATION OF HISTONES LEADS TO COMPACT CHROMATIN WITH REDUCED ACCESSIBILITY TO THE TRANSCRIPTIONAL MACHINERY. METHYL-CPG BINDING PROTEINS CAN RECRUIT COREPRESSORS AND HISTONE DEACETYLASES; THUS, THE INTERPLAY BETWEEN THESE EPIGENETIC MECHANISMS REGULATES GENE ACTIVATION. METHYLATION HAS BEEN IMPLICATED AS AN IMPORTANT MECHANISM DURING IMMUNE DEVELOPMENT, CONTROLLING VDJ RECOMBINATION, LINEAGE-SPECIFIC EXPRESSION OF CELL SURFACE ANTIGENS, AND TRANSCRIPTIONAL REGULATION OF CYTOKINE GENES DURING IMMUNE RESPONSES. ABERRATIONS IN EPIGENETIC MACHINERY, EITHER BY GENETIC MUTATIONS OR BY SOMATIC CHANGES SUCH AS VIRAL INFECTIONS, ARE ASSOCIATED WITH EARLY ALTERATIONS IN CHRONIC DISEASES SUCH AS IMMUNODEFICIENCY AND CANCER. 2003 4 3527 32 IL-6 ENHANCES THE NUCLEAR TRANSLOCATION OF DNA CYTOSINE-5-METHYLTRANSFERASE 1 (DNMT1) VIA PHOSPHORYLATION OF THE NUCLEAR LOCALIZATION SEQUENCE BY THE AKT KINASE. THE EPIGENETIC PROGRAMMING OF GENOMIC DNA IS ACCOMPLISHED, IN PART, BY SEVERAL DNA CYTOSINE-5-METHYLTRANSFERASES THAT ACT BY COVALENTLY MODIFYING CYTOSINES WITH THE ADDITION OF A METHYL GROUP. THIS COVALENT MODIFICATION IS MAINTAINED BY THE DNA CYTOSINE-5-METHYLTRANSFERASE-1 ENZYME (DNMT1), WHICH IS CAPABLE OF ACTING IN CONCERT WITH OTHER SIMILAR ENZYMES TO SILENCE IMPORTANT TUMOR SUPPRESSOR GENES. IL-6 IS A MULTIFUNCTIONAL MEDIATOR OF INFLAMMATION, ACTING THROUGH SEVERAL MAJOR SIGNALING CASCADES, INCLUDING THE PHOSPHATIDYLINOSITOL-3-KINASE PATHWAY (PI-3-K), WHICH ACTIVATES PROTEIN KINASE B (AKT/PKB) DOWNSTREAM. HERE, WE SHOW THAT THE SUBCELLULAR LOCALIZATION OF DNMT1 CAN BE ALTERED BY THE ADDITION OF IL-6, INCREASING THE RATE OF NUCLEAR TRANSLOCATION OF THE ENZYME FROM THE CYTOSOLIC COMPARTMENT. THE MECHANISM OF NUCLEAR TRANSLOCATION OF DNMT1 IS GREATLY ENHANCED BY PHOSPHORYLATION OF THE DNMT1 NUCLEAR LOCALIZATION SIGNAL (NLS) BY PKB/AKT KINASE. MUTAGENIC ALTERATION OF THE TWO AKT TARGET AMINO ACIDS WITHIN THE NLS RESULTS IN A MAJOR LOSS OF DNMT1 NUCLEAR TRANSLOCATION, WHILE THE CREATION OF A "PHOSPHO-MIMIC" AMINO ACID (MUTATION TO ACIDIC RESIDUES) RESTORES THIS COMPARTMENTATION ABILITY. THESE OBSERVATIONS SUGGEST AN INTERESTING HYPOTHESIS REGARDING HOW MEDIATORS OF CHRONIC INFLAMMATION MAY DISTURB THE DELICATE BALANCE OF CELLULAR COMPARTMENTALIZATION OF IMPORTANT PROTEINS, AND REVEALS A POTENTIAL MECHANISM FOR THE INDUCTION OR ENHANCEMENT OF TUMOR GROWTH VIA ALTERATION OF THE COMPONENTS INVOLVED IN THE EPIGENETIC PROGRAMMING OF A CELL. 2007 5 2926 31 GENERATION OF AN EPIGENETIC SIGNATURE BY CHRONIC HYPOXIA IN PROSTATE CELLS. INCREASING LEVELS OF TISSUE HYPOXIA HAVE BEEN REPORTED AS A NATURAL FEATURE OF THE AGING PROSTATE GLAND AND MAY BE A RISK FACTOR FOR THE DEVELOPMENT OF PROSTATE CANCER. IN THIS STUDY, WE HAVE USED PWR-1E BENIGN PROSTATE EPITHELIAL CELLS AND AN EQUIVALENTLY AGED HYPOXIA-ADAPTED PWR-1E SUB-LINE TO IDENTIFY PHENOTYPIC AND EPIGENETIC CONSEQUENCES OF CHRONIC HYPOXIA IN PROSTATE CELLS. WE HAVE IDENTIFIED A SIGNIFICANTLY ALTERED CELLULAR PHENOTYPE IN RESPONSE TO CHRONIC HYPOXIA AS CHARACTERIZED BY INCREASED RECEPTOR-MEDIATED APOPTOTIC RESISTANCE, THE INDUCTION OF CELLULAR SENESCENCE, INCREASED INVASION AND THE INCREASED SECRETION OF IL-1 BETA, IL6, IL8 AND TNFALPHA CYTOKINES. IN ASSOCIATION WITH THESE PHENOTYPIC CHANGES AND THE ABSENCE OF HIF-1 ALPHA PROTEIN EXPRESSION, WE HAVE DEMONSTRATED SIGNIFICANT INCREASES IN GLOBAL LEVELS OF DNA METHYLATION AND H3K9 HISTONE ACETYLATION IN THESE CELLS, CONCOMITANT WITH THE INCREASED EXPRESSION OF DNA METHYLTRANSFERASE DMNT3B AND GENE-SPECIFIC CHANGES IN DNA METHYLATION AT KEY IMPRINTING LOCI. IN CONCLUSION, WE HAVE DEMONSTRATED A GENOME-WIDE ADJUSTMENT OF DNA METHYLATION AND HISTONE ACETYLATION UNDER CHRONIC HYPOXIC CONDITIONS IN THE PROSTATE. THESE EPIGENETIC SIGNATURES MAY REPRESENT AN ADDITIONAL MECHANISM TO PROMOTE AND MAINTAIN A HYPOXIC-ADAPTED CELLULAR PHENOTYPE WITH A POTENTIAL ROLE IN TUMOUR DEVELOPMENT. 2009 6 4497 40 MORPHINE LEADS TO GLOBAL GENOME CHANGES IN H3K27ME3 LEVELS VIA A POLYCOMB REPRESSIVE COMPLEX 2 (PRC2) SELF-REGULATORY MECHANISM IN MESCS. BACKGROUND: ENVIRONMENTALLY INDUCED EPIGENETIC CHANGES CAN LEAD TO HEALTH PROBLEMS OR DISEASE, BUT THE MECHANISMS INVOLVED REMAIN UNCLEAR. MORPHINE CAN PASS THROUGH THE PLACENTAL BARRIER LEADING TO ABNORMAL EMBRYO DEVELOPMENT. HOWEVER, THE MECHANISM BY WHICH MORPHINE CAUSES THESE EFFECTS AND HOW THEY SOMETIMES PERSIST INTO ADULTHOOD IS NOT WELL KNOWN. TO UNRAVEL THE MORPHINE-INDUCED CHROMATIN ALTERATIONS INVOLVED IN ABERRANT EMBRYO DEVELOPMENT, WE EXPLORED THE ROLE OF THE H3K27ME3/PRC2 REPRESSIVE COMPLEX IN GENE EXPRESSION AND ITS TRANSMISSION ACROSS CELLULAR GENERATIONS IN RESPONSE TO MORPHINE. RESULTS: USING MOUSE EMBRYONIC STEM CELLS AS A MODEL SYSTEM, WE FOUND THAT CHRONIC MORPHINE TREATMENT INDUCES A GLOBAL DOWNREGULATION OF THE HISTONE MODIFICATION H3K27ME3. CONVERSELY, CHIP-SEQ SHOWED A REMARKABLE INCREASE IN H3K27ME3 LEVELS AT SPECIFIC GENOMIC SITES, PARTICULARLY PROMOTERS, DISRUPTING SELECTIVE TARGET GENES RELATED TO EMBRYO DEVELOPMENT, CELL CYCLE AND METABOLISM. THROUGH A SELF-REGULATORY MECHANISM, MORPHINE DOWNREGULATED THE TRANSCRIPTION OF PRC2 COMPONENTS RESPONSIBLE FOR H3K27ME3 BY ENRICHING HIGH H3K27ME3 LEVELS AT THE PROMOTER REGION. DOWNREGULATION OF PRC2 COMPONENTS PERSISTED FOR AT LEAST 48 H (4 CELL CYCLES) FOLLOWING MORPHINE REMOVAL, THOUGH PROMOTER H3K27ME3 LEVELS RETURNED TO CONTROL LEVELS. CONCLUSIONS: MORPHINE INDUCES TARGETING OF THE PRC2 COMPLEX TO SELECTED PROMOTERS, INCLUDING THOSE OF PRC2 COMPONENTS, LEADING TO CHARACTERISTIC CHANGES IN GENE EXPRESSION AND A GLOBAL REDUCTION IN H3K27ME3. FOLLOWING MORPHINE REMOVAL, ENHANCED PROMOTER H3K27ME3 LEVELS REVERT TO NORMAL SOONER THAN GLOBAL H3K27ME3 OR PRC2 COMPONENT TRANSCRIPT LEVELS. WE SUGGEST THAT H3K27ME3 IS INVOLVED IN INITIATING MORPHINE-INDUCED CHANGES IN GENE EXPRESSION, BUT NOT IN THEIR MAINTENANCE. MODEL OF POLYCOMB REPRESSIVE COMPLEX 2 (PRC2) AND H3K27ME3 ALTERATIONS INDUCED BY CHRONIC MORPHINE EXPOSURE. MORPHINE INDUCES H3K27ME3 ENRICHMENT AT PROMOTERS OF GENES ENCODING CORE MEMBERS OF THE PRC2 COMPLEX AND IS ASSOCIATED WITH THEIR TRANSCRIPTIONAL DOWNREGULATION. 2020 7 3360 37 HISTONE H4K20 TRIMETHYLATION IS DECREASED IN MURINE MODELS OF HEART DISEASE. HEART DISEASE IS THE LEADING CAUSE OF DEATH IN THE DEVELOPED WORLD, AND ITS COMORBIDITIES SUCH AS HYPERTENSION, DIABETES, AND HEART FAILURE ARE ACCOMPANIED BY MAJOR TRANSCRIPTOMIC CHANGES IN THE HEART. DURING CARDIAC DYSFUNCTION, WHICH LEADS TO HEART FAILURE, THERE ARE GLOBAL EPIGENETIC ALTERATIONS TO CHROMATIN THAT OCCUR CONCOMITANTLY WITH MORPHOLOGICAL CHANGES IN THE HEART IN RESPONSE TO ACUTE AND CHRONIC STRESS. THESE EPIGENETIC ALTERATIONS INCLUDE THE REVERSIBLE METHYLATION OF LYSINE RESIDUES ON HISTONE PROTEINS. LYSINE METHYLATIONS ON HISTONES H3K4 AND H3K9 WERE AMONG THE FIRST METHYLATED LYSINE RESIDUES IDENTIFIED AND HAVE BEEN LINKED TO GENE ACTIVATION AND SILENCING, RESPECTIVELY. HOWEVER, MUCH LESS IS KNOWN REGARDING OTHER METHYLATED HISTONE RESIDUES, INCLUDING HISTONE H4K20. TRIMETHYLATION OF HISTONE H4K20 HAS BEEN SHOWN TO REPRESS GENE EXPRESSION; HOWEVER, THIS MODIFICATION HAS NEVER BEEN EXAMINED IN THE HEART. HERE, WE UTILIZED IMMUNOBLOTTING AND MASS SPECTROMETRY TO QUANTIFY HISTONE H4K20 TRIMETHYLATION IN THREE MODELS OF CARDIAC DYSFUNCTION. OUR RESULTS SHOW THAT LYSINE METHYLATION AT THIS SITE IS DIFFERENTIALLY REGULATED IN THE CARDIOMYOCYTE, LEADING TO INCREASED H4K20 TRIMETHYLATION DURING ACUTE HYPERTROPHIC STRESS IN CELL MODELS AND DECREASED H4K20 TRIMETHYLATION DURING SUSTAINED ISCHEMIC INJURY AND CARDIAC DYSFUNCTION IN ANIMAL MODELS. IN ADDITION, WE EXAMINED PUBLICLY AVAILABLE DATA SETS TO ANALYZE ENZYMES THAT REGULATE H4K20 METHYLATION AND IDENTIFIED TWO DEMETHYLASES (KDM7B AND KDM7C) AND TWO METHYLTRANSFERASES (KMT5A AND SMYD5) THAT WERE ALL DIFFERENTIALLY EXPRESSED IN HEART FAILURE PATIENTS. THIS IS THE FIRST STUDY TO EXAMINE HISTONE H4K20 TRIMETHYLATION IN THE HEART AND TO DETERMINE HOW THIS POST-TRANSLATIONAL MODIFICATION IS DIFFERENTIALLY REGULATED IN MULTIPLE MODELS OF CARDIAC DISEASE. 2022 8 1326 28 DEPLETION OF NUCLEAR HISTONE H2A VARIANTS IS ASSOCIATED WITH CHRONIC DNA DAMAGE SIGNALING UPON DRUG-EVOKED SENESCENCE OF HUMAN SOMATIC CELLS. CELLULAR SENESCENCE IS ASSOCIATED WITH GLOBAL CHROMATIN CHANGES, ALTERED GENE EXPRESSION, AND ACTIVATION OF CHRONIC DNA DAMAGE SIGNALING. THESE EVENTS ULTIMATELY LEAD TO MORPHOLOGICAL AND PHYSIOLOGICAL TRANSFORMATIONS IN PRIMARY CELLS. IN THIS STUDY, WE SHOW THAT CHRONIC DNA DAMAGE SIGNALS CAUSED BY GENOTOXIC STRESS IMPACT THE EXPRESSION OF HISTONES H2A FAMILY MEMBERS AND LEAD TO THEIR DEPLETION IN THE NUCLEI OF SENESCENT HUMAN FIBROBLASTS. OUR DATA REINFORCE THE HYPOTHESIS THAT PROGRESSIVE CHROMATIN DESTABILIZATION MAY LEAD TO THE LOSS OF EPIGENETIC INFORMATION AND IMPAIRED CELLULAR FUNCTION ASSOCIATED WITH CHRONIC DNA DAMAGE UPON DRUG-EVOKED SENESCENCE. WE PROPOSE THAT CHANGES IN THE HISTONE BIOSYNTHESIS AND CHROMATIN ASSEMBLY MAY DIRECTLY CONTRIBUTE TO CELLULAR AGING. IN ADDITION, WE ALSO OUTLINE THE METHOD THAT ALLOWS FOR QUANTITATIVE AND UNBIASED MEASUREMENT OF THESE CHANGES. 2012 9 6431 31 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 10 347 38 ALTERED DNA METHYLATION IN KIDNEY DISEASE: USEFUL MARKERS AND THERAPEUTIC TARGETS. RECENT STUDIES HAVE DEMONSTRATED THE ASSOCIATION OF ALTERED EPIGENOMES WITH LIFESTYLE-RELATED DISEASES. EPIGENETIC REGULATION PROMOTES BIOLOGICAL PLASTICITY IN RESPONSE TO ENVIRONMENTAL CHANGES, AND SUCH PLASTICITY MAY CAUSE A 'MEMORY EFFECT', A SUSTAINED EFFECT OF TRANSIENT TREATMENT OR AN INSULT IN THE COURSE OF LIFESTYLE-RELATED DISEASES. WE INVESTIGATED THE SIGNIFICANCE OF EPIGENETIC CHANGES IN SEVERAL GENES REQUIRED FOR RENAL INTEGRITY, INCLUDING THE NEPHRIN GENE IN PODOCYTES, AND THE SUSTAINED ANTI-PROTEINURIC EFFECT, FOCUSING ON THE TRANSCRIPTION FACTOR KRUPPEL-LIKE FACTOR 4 (KLF4). WE FURTHER REPORTED THE ROLE OF THE DNA REPAIR FACTOR LYSINE-ACETYL TRANSFERASE 5 (KAT5), WHICH ACTS COORDINATELY WITH KLF4, IN PODOCYTE INJURY CAUSED BY A HYPERGLYCEMIC STATE THROUGH THE ACCELERATION OF DNA DAMAGE AND EPIGENETIC ALTERATION. IN CONTRAST, KAT5 IN PROXIMAL TUBULAR CELLS PREVENTS ACUTE KIDNEY INJURY VIA GLOMERULAR FILTRATION REGULATION BY AN EPIGENETIC MECHANISM AS WELL AS PROMOTION OF DNA REPAIR, INDICATING THE CELL TYPE-SPECIFIC ACTION AND ROLES OF DNA REPAIR FACTORS. THIS REVIEW SUMMARIZES EPIGENETIC ALTERATIONS IN KIDNEY DISEASES, ESPECIALLY DNA METHYLATION, AND THEIR UTILITY AS MARKERS AND POTENTIAL THERAPEUTIC TARGETS. FOCUSING ON TRANSCRIPTION FACTORS OR DNA DAMAGE REPAIR FACTORS ASSOCIATED WITH EPIGENETIC CHANGES MAY BE MEANINGFUL DUE TO THEIR CELL-SPECIFIC EXPRESSION OR ACTION. WE BELIEVE THAT A BETTER UNDERSTANDING OF EPIGENETIC ALTERATIONS IN THE KIDNEY WILL LEAD TO THE DEVELOPMENT OF A NOVEL STRATEGY FOR CHRONIC KIDNEY DISEASE (CKD) TREATMENT. 2022 11 273 42 AGE-INDUCED SUPPRESSION OF EZH2 MEDIATES INJURY OF PODOCYTES BY REDUCING H3K27ME3. BACKGROUND: CHRONIC HYPERGLYCEMIA, A PIVOTAL FEATURE OF DIABETES MELLITUS (DM), INITIATES THE FORMATION OF ADVANCED GLYCATION END PRODUCTS (AGES) AND THE DYSREGULATION OF EPIGENETIC MECHANISMS, WHICH MAY CAUSE INJURY TO RENAL PODOCYTES, A CENTRAL FEATURE OF DIABETIC KIDNEY DISEASE (DKD). PREVIOUS DATA OF OUR GROUP SHOWED THAT AGES SIGNIFICANTLY REDUCE THE EXPRESSION OF NIPP1 (NUCLEAR INHIBITOR OF PROTEIN PHOSPHATASE 1) IN PODOCYTES IN VITRO AS WELL AS IN HUMAN AND MURINE DKD. NIPP1 WAS SHOWN BY OTHERS TO INTERACT WITH ENHANCER OF ZESTE HOMOLOG 2 (EZH2), WHICH CATALYZES THE REPRESSIVE METHYLATION OF H3K27ME3 ON HISTONE 3. THEREFORE, WE HYPOTHESIZED THAT AGES CAN DIRECTLY INDUCE EPIGENETIC CHANGES IN PODOCYTES. METHODS: WE ANALYZED THE RELEVANCE OF AGES ON EZH2 EXPRESSION AND ACTIVITY IN A MURINE PODOCYTE CELL LINE. CELLS WERE TREATED WITH 5 MG/ML GLYCATED BSA FOR 24 H. TO DETERMINE THE MEANING OF EZH2 SUPPRESSION, EZH2 ACTIVITY WAS INHIBITED BY INCUBATING THE CELLS WITH THE PHARMACOLOGICAL METHYLTRANSFERASE INHIBITOR 3-DEAZANEPLANOCIN A; EZH2 EXPRESSION WAS REPRESSED WITH SIRNA. MRNA EXPRESSION WAS ANALYZED WITH REAL-TIME PCR, AND PROTEIN EXPRESSION WITH WESTERN BLOT. EZH2 EXPRESSION AND LEVEL OF H3K27 TRIMETHYLATION IN PODOCYTES OF DIABETIC DB/DB MICE, A MOUSE MODEL FOR TYPE 2 DM, WERE ANALYZED USING IMMUNOFLUORESCENCE. RESULTS: OUR DATA DEMONSTRATED THAT AGES DECREASE EZH2 EXPRESSION IN PODOCYTES AND CONSEQUENTLY REDUCE H3K27ME3. THIS SUPPRESSION OF EZH2 MIMICKED THE AGE EFFECTS AND CAUSED AN UPREGULATED EXPRESSION OF PATHOLOGICAL FACTORS THAT CONTRIBUTE TO PODOCYTE INJURY IN DKD. IN ADDITION, ANALYSES OF DB/DB MICE SHOWED SIGNIFICANTLY REDUCED H3K27ME3 AND EZH2 EXPRESSION IN PODOCYTES. MOREOVER, THE SUPPRESSION OF NIPP1 AND EZH2 SHOWED SIMILAR EFFECTS REGARDING PODOCYTE INJURY. CONCLUSIONS: OUR STUDIES PROVIDE A NOVEL PATHWAY HOW AGES CONTRIBUTE TO PODOCYTE INJURY AND THE FORMATION OF THE SO-CALLED METABOLIC MEMORY IN DKD. 2020 12 5067 32 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 13 2493 41 EPIGENETICS AND CHROMATIN REMODELING PLAY A ROLE IN LUNG DISEASE. EPIGENETICS IS DEFINED AS HERITABLE CHANGES THAT AFFECT GENE EXPRESSION WITHOUT ALTERING THE DNA SEQUENCE. EPIGENETIC REGULATION OF GENE EXPRESSION IS FACILITATED THROUGH DIFFERENT MECHANISMS SUCH AS DNA METHYLATION, HISTONE MODIFICATIONS AND RNA-ASSOCIATED SILENCING BY SMALL NON-CODING RNAS. ALL THESE MECHANISMS ARE CRUCIAL FOR NORMAL DEVELOPMENT, DIFFERENTIATION AND TISSUE-SPECIFIC GENE EXPRESSION. THESE THREE SYSTEMS INTERACT AND STABILIZE ONE ANOTHER AND CAN INITIATE AND SUSTAIN EPIGENETIC SILENCING, THUS DETERMINING HERITABLE CHANGES IN GENE EXPRESSION. HISTONE ACETYLATION REGULATES DIVERSE CELLULAR FUNCTIONS INCLUDING INFLAMMATORY GENE EXPRESSION, DNA REPAIR AND CELL PROLIFERATION. TRANSCRIPTIONAL COACTIVATORS POSSESS INTRINSIC HISTONE ACETYLTRANSFERASE ACTIVITY AND THIS ACTIVITY DRIVES INFLAMMATORY GENE EXPRESSION. ELEVEN CLASSICAL HISTONE DEACETYLASES (HDACS) ACT TO REGULATE THE EXPRESSION OF DISTINCT SUBSETS OF INFLAMMATORY/IMMUNE GENES. THUS, LOSS OF HDAC ACTIVITY OR THE PRESENCE OF HDAC INHIBITORS CAN FURTHER ENHANCE INFLAMMATORY GENE EXPRESSION BY PRODUCING A GENE-SPECIFIC CHANGE IN HAT ACTIVITY. FOR EXAMPLE, HDAC2 EXPRESSION AND ACTIVITY ARE REDUCED IN LUNG MACROPHAGES, BIOPSY SPECIMENS, AND BLOOD CELLS FROM PATIENTS WITH SEVERE ASTHMA AND SMOKING ASTHMATICS, AS WELL AS IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). THIS MAY ACCOUNT, AT LEAST IN PART, FOR THE ENHANCED INFLAMMATION AND REDUCED STEROID RESPONSIVENESS SEEN IN THESE PATIENTS. OTHER PROTEINS, PARTICULARLY TRANSCRIPTION FACTORS, ARE ALSO ACETYLATED AND ARE TARGETS FOR DEACETYLATION BY HDACS AND SIRTUINS, A RELATED FAMILY OF 7 PREDOMINANTLY PROTEIN DEACETYLASES. THUS THE ACETYLATION/DEACETYLATION STATUS OF NF-KAPPAB AND THE GLUCOCORTICOID RECEPTOR CAN ALSO AFFECT THE OVERALL EXPRESSION PATTERN OF INFLAMMATORY GENES AND REGULATE THE INFLAMMATORY RESPONSE. UNDERSTANDING AND TARGETING SPECIFIC ENZYMES INVOLVED IN THIS PROCESS MIGHT LEAD TO NEW THERAPEUTIC AGENTS, PARTICULARLY IN SITUATIONS IN WHICH CURRENT ANTI-INFLAMMATORY THERAPIES ARE SUBOPTIMAL. 2011 14 141 27 ABERRANT DNA METHYLATION OF MTOR PATHWAY GENES PROMOTES INFLAMMATORY ACTIVATION OF IMMUNE CELLS IN DIABETIC KIDNEY DISEASE. DNA METHYLATION HAS BEEN IMPLICATED IN THE PATHOGENESIS OF DIABETIC KIDNEY DISEASE (DKD), BUT THE UNDERLYING MECHANISMS REMAIN UNCLEAR. IN THIS STUDY, WE TESTED THE HYPOTHESIS THAT ABERRANT DNA METHYLATION IN PERIPHERAL IMMUNE CELLS CONTRIBUTES TO DKD PROGRESSION. WE SHOWED THAT LEVELS OF DNA METHYLTRANSFERASE 1 (DNMT1), A KEY ENZYME FOR DNA METHYLATION, WERE INCREASED ALONG WITH INFLAMMATORY ACTIVITY OF PERIPHERAL BLOOD MONONUCLEAR CELLS IN DKD PATIENTS. INHIBITION OF DNMT1 WITH 5-AZA-2'-DEOXYCYTIDINE (5-AZA) MARKEDLY INCREASED THE PROPORTION OF CD4(+)CD25(+) REGULATORY T CELLS IN PERIPHERAL BLOOD MONONUCLEAR CELLS IN CULTURE AND IN DIABETIC ANIMALS. ADOPTIVE TRANSFER OF IMMUNE CELLS FROM 5-AZA-TREATED ANIMALS SHOWED BENEFICIAL EFFECTS ON THE HOST IMMUNE SYSTEM, RESULTING IN A SIGNIFICANT IMPROVEMENT OF DKD. USING GENOME-WIDE DNA METHYLATION ASSAYS, WE IDENTIFIED THE DIFFERENTIALLY METHYLATED CYTOSINES IN THE PROMOTER REGIONS OF MAMMALIAN TARGET OF RAPAMYCIN (MTOR) REGULATORS IN PERIPHERAL BLOOD MONONUCLEAR CELLS OF DIABETIC PATIENTS. FURTHER, MRNA ARRAYS CONFIRMED THE CONSISTENT INDUCTION OF GENES EXPRESSED IN THE MTOR PATHWAY. IMPORTANTLY, DOWN-REGULATION OF DNMT1 EXPRESSION VIA RNA INTERFERENCE RESULTED IN PROMINENT CYTOSINE DEMETHYLATION OF MTOR NEGATIVE REGULATORS AND SUBSEQUENT DECREASE OF MTOR ACTIVITY. LASTLY, MODULATION OF MTOR RESULTED IN CHANGES IN THE EFFECT OF 5-AZA ON DIABETIC IMMUNE CELLS. THUS, UP-REGULATION OF DNMT1 IN DIABETIC IMMUNE CELLS INDUCES ABERRANT CYTOSINE METHYLATION OF THE UPSTREAM REGULATORS OF MTOR, LEADING TO PATHOGENIC ACTIVATION OF THE MTOR PATHWAY AND CONSEQUENT INFLAMMATION IN DIABETIC KIDNEYS. HENCE, THIS STUDY HIGHLIGHTS THERAPEUTIC POTENTIAL OF TARGETING EPIGENETIC EVENTS IN IMMUNE SYSTEM FOR TREATING DKD. 2019 15 834 27 CHEMICAL BIOLOGY OF LYSINE DEMETHYLASES. ABNORMAL LEVELS OF DNA METHYLATION AND/OR HISTONE MODIFICATIONS ARE OBSERVED IN PATIENTS WITH A WIDE VARIETY OF CHRONIC DISEASES. METHYLATION OF LYSINES WITHIN HISTONE TAILS IS A KEY MODIFICATION THAT CONTRIBUTES TO INCREASED GENE EXPRESSION OR REPRESSION DEPENDING ON THE SPECIFIC RESIDUE AND DEGREE OF METHYLATION, WHICH IS IN TURN CONTROLLED BY THE INTERPLAY OF LYSINE METHYL TRANSFERASES AND DEMETHYLASES. DRUGS THAT TARGET THESE AND OTHER ENZYMES CONTROLLING CHROMATIN MODIFICATIONS CAN MODULATE THE EXPRESSION OF CLUSTERS OF GENES, POTENTIALLY OFFERING HIGHER THERAPEUTIC EFFICACY THAN CLASSICAL AGENTS ACTING ON DOWNSTREAM BIOCHEMICAL PATHWAYS THAT ARE SUSCEPTIBLE TO DEGENERACY. LYSINE DEMETHYLASES, FIRST DISCOVERED IN 2004, ARE THE SUBJECT OF INCREASING INTEREST AS THERAPEUTIC TARGETS. THIS REVIEW PROVIDES AN OVERVIEW OF RECENT FINDINGS IMPLICATING LYSINE DEMETHYLASES IN A RANGE OF THERAPEUTIC AREAS INCLUDING ONCOLOGY, IMMUNOINFLAMMATION, METABOLIC DISORDERS, NEUROSCIENCE, VIROLOGY AND REGENERATIVE MEDICINE, TOGETHER WITH A SUMMARY OF RECENT ADVANCES IN STRUCTURAL BIOLOGY AND SMALL MOLECULE INHIBITOR DISCOVERY, SUPPORTING THE TRACTABILITY OF THE PROTEIN FAMILY FOR THE DEVELOPMENT OF SELECTIVE DRUGLIKE INHIBITORS. 2011 16 3367 28 HISTONE METHYLTRANSFERASE EZH2: A POTENTIAL THERAPEUTIC TARGET FOR KIDNEY DISEASES. ENHANCER OF ZESTE HOMOLOG 2 (EZH2) IS A HISTONE-LYSINE N-METHYLTRANSFERASE ENZYME THAT CATALYZES THE ADDITION OF METHYL GROUPS TO HISTONE H3 AT LYSINE 27, LEADING TO GENE SILENCING. MUTATION OR OVER-EXPRESSION OF EZH2 HAS BEEN LINKED TO MANY CANCERS INCLUDING RENAL CARCINOMA. RECENT STUDIES HAVE SHOWN THAT EZH2 EXPRESSION AND ACTIVITY ARE ALSO INCREASED IN SEVERAL ANIMAL MODELS OF KIDNEY INJURY, SUCH AS ACUTE KIDNEY INJURY (AKI), RENAL FIBROSIS, DIABETIC NEPHROPATHY, LUPUS NEPHRITIS (LN), AND RENAL TRANSPLANTATION REJECTION. THE PHARMACOLOGICAL AND/OR GENETIC INHIBITION OF EZH2 CAN ALLEVIATE AKI, RENAL FIBROSIS, AND LN, BUT POTENTIATE PODOCYTE INJURY IN ANIMAL MODELS, SUGGESTING THAT THE FUNCTIONAL ROLE OF EZH2 VARIES WITH RENAL CELL TYPE AND DISEASE MODEL. IN THIS ARTICLE, WE SUMMARIZE THE ROLE OF EZH2 IN THE PATHOLOGY OF RENAL INJURY AND RELEVANT MECHANISMS AND HIGHLIGHT EZH2 AS A POTENTIAL THERAPEUTIC TARGET FOR KIDNEY DISEASES. 2021 17 2280 37 EPIGENETIC REGULATION IN DRUG ADDICTION. THE INTERACTION BETWEEN ENVIRONMENTAL SIGNALS AND GENES HAS NOW TAKEN ON A CLEAR MOLECULAR FORM AS DEMONSTRATED BY STABLE CHANGES IN CHROMATIN STRUCTURE. THESE CHANGES OCCUR THROUGH ACTIVATION OR REPRESSION OF SPECIFIC GENE PROGRAMMES BY A COMBINATION OF CHROMATIN REMODELLING, ACTIVATION AND ENZYMATIC MODIFICATION OF DNA AND HISTONES AS WELL AS NUCLEOSOMAL SUBUNIT EXCHANGE. RECENT RESEARCH INVESTIGATING THE MOLECULAR MECHANISMS CONTROLLING DRUG-INDUCED TRANSCRIPTIONAL, BEHAVIOURAL AND SYNAPTIC ACTIVITY HAS SHOWN A DIRECT ROLE FOR CHROMATIN REMODELLING--TERMED AS EPIGENETIC REGULATION--OF NEURONAL GENE PROGRAMMES AND SUBSEQUENT ADDICTIVE BEHAVIOUR ARISING FROM IT. RECENT DATA SUGGEST THAT REPEATED EXPOSURE TO CERTAIN DRUGS PROMOTES CHANGES IN LEVELS OF HISTONE ACETYLATION, PHOSPHORYLATION AND METHYLATION, TOGETHER WITH ALTERATIONS IN DNA METHYLATION LEVELS IN THE NEURONS OF THE BRAIN REWARD CENTRE, LOCALISED IN THE NUCLEUS ACCUMBENS (NAC) REGION OF THE LIMBIC SYSTEM. THE COMBINATION OF ACETYLATING, PHOSPHORYLATING AND METHYLATING H3 AND H4 HISTONE TAILS ALTER CHROMATIN COMPACTION THEREBY PROMOTING ALTERED LEVELS OF CELLULAR GENE EXPRESSION. HISTONE MODIFICATIONS, WHICH WEAKEN HISTONE INTERACTION WITH DNA OR THAT PROMOTE RECRUITMENT OF TRANSCRIPTIONAL ACTIVATING COMPLEXES, CORRELATE WITH PERMISSIVE GENE EXPRESSION. HISTONE DEACETYLATION, (WHICH STRENGTHEN HISTONE: DNA CONTACTS), OR HISTONE METHYLATION, (WHICH RECRUITS REPRESSIVE COMPLEXES TO CHROMATIN), PROMOTE A STATE OF TRANSCRIPTIONAL REPRESSION. USING ANIMAL MODELS, ACUTE COCAINE TREATMENT INCREASES H4 ACETYLATION AT ACUTELY REGULATED GENE PROMOTERS, WHEREAS H3 ACETYLATION APPEARS TO PREDOMINATE AT CHRONICALLY INDUCED PROMOTERS. CHRONIC COCAINE AND ALCOHOL TREATMENT ACTIVATE AND REPRESS MANY GENES SUCH AS FOSB, CDK5, AND BDNF, WHERE THEIR DYSREGULATION, AT THE CHROMATIN LEVEL, CONTRIBUTE TO THE DEVELOPMENT AND MAINTENANCE OF ADDICTION. FOLLOWING DRUG EXPOSURE, IT IS STILL UNKNOWN, HOWVER, HOW LONG THESE CHANGES IN CHROMATIN STRUCTURE PERSIST IN AFFECTING NEURONAL FUNCTION, BUT SOME DO SO FOR LIFE. 2012 18 5972 21 TET REPRESSION AND INCREASED DNMT ACTIVITY SYNERGISTICALLY INDUCE ABERRANT DNA METHYLATION. CHRONIC INFLAMMATION IS DEEPLY INVOLVED IN VARIOUS HUMAN DISORDERS, SUCH AS CANCER, NEURODEGENERATIVE DISORDERS, AND METABOLIC DISORDERS. INDUCTION OF EPIGENETIC ALTERATIONS, ESPECIALLY ABERRANT DNA METHYLATION, IS ONE OF THE MAJOR MECHANISMS, BUT HOW IT IS INDUCED IS STILL UNCLEAR. HERE, WE FOUND THAT EXPRESSION OF TET GENES, METHYLATION ERASERS, WAS DOWNREGULATED IN INFLAMED MOUSE AND HUMAN TISSUES, AND THAT THIS WAS CAUSED BY UPREGULATION OF TET-TARGETING MIRNAS SUCH AS MIR20A, MIR26B, AND MIR29C, LIKELY DUE TO ACTIVATION OF NF-KAPPAB SIGNALING DOWNSTREAM OF IL-1BETA AND TNF-ALPHA. HOWEVER, TET KNOCKDOWN INDUCED ONLY MILD ABERRANT METHYLATION. NITRIC OXIDE (NO), PRODUCED BY NOS2, ENHANCED ENZYMATIC ACTIVITY OF DNA METHYLTRANSFERASES (DNMTS), METHYLATION WRITERS, AND NO EXPOSURE INDUCED MINIMAL ABERRANT METHYLATION. IN CONTRAST, A COMBINATION OF TET KNOCKDOWN AND NO EXPOSURE SYNERGISTICALLY INDUCED ABERRANT METHYLATION, INVOLVING GENOMIC REGIONS NOT METHYLATED BY EITHER ALONE. THE RESULTS SHOWED THAT A VICIOUS COMBINATION OF TET REPRESSION, DUE TO NF-KAPPAB ACTIVATION, AND DNMT ACTIVATION, DUE TO NO PRODUCTION, IS RESPONSIBLE FOR ABERRANT METHYLATION INDUCTION IN HUMAN TISSUES. 2020 19 3658 34 INDUCTION OF ABERRANT TRIMETHYLATION OF HISTONE H3 LYSINE 27 BY INFLAMMATION IN MOUSE COLONIC EPITHELIAL CELLS. A FIELD FOR CANCERIZATION (FIELD DEFECT), WHERE GENETIC AND EPIGENETIC ALTERATIONS ARE ACCUMULATED IN NORMAL-APPEARING TISSUES, IS INVOLVED IN HUMAN CARCINOGENESIS, ESPECIALLY CANCERS ASSOCIATED WITH CHRONIC INFLAMMATION. ALTHOUGH ABERRANT DNA METHYLATION IS INVOLVED IN THE FIELD DEFECT AND INDUCED BY CHRONIC INFLAMMATION, IT IS STILL UNCLEAR FOR TRIMETHYLATION OF HISTONE H3 LYSINE 27 (H3K27ME3), WHICH IS INVOLVED IN GENE REPRESSION INDEPENDENT OF DNA METHYLATION AND FUNCTIONS AS A PRE-MARK FOR ABERRANT DNA METHYLATION. IN THIS STUDY, USING A MOUSE COLITIS MODEL INDUCED BY DEXTRAN SULFATE SODIUM (DSS), WE AIMED TO CLARIFY WHETHER ABERRANT H3K27ME3 IS INDUCED BY INFLAMMATION AND INVOLVED IN A FIELD DEFECT. CHIP-ON-CHIP ANALYSIS OF COLONIC EPITHELIAL CELLS REVEALED THAT H3K27ME3 LEVELS WERE INCREASED OR DECREASED FOR 266 GENOMIC REGIONS BY AGING, AND MORE EXTENSIVELY (23 INCREASED AND 3574 DECREASED REGIONS) BY COLITIS. SUCH INCREASE OR DECREASE OF H3K27ME3 WAS INDUCED AS EARLY AS 2 WEEKS AFTER THE INITIATION OF DSS TREATMENT, AND PERSISTED AT LEAST FOR 16 WEEKS EVEN AFTER THE INFLAMMATION DISAPPEARED. SOME OF THE ABERRANT H3K27ME3 IN COLONIC EPITHELIAL CELLS WAS CARRIED OVER INTO COLON TUMORS. FURTHERMORE, H3K27ME3 ACQUIRED AT DAPK1 BY COLITIS WAS FOLLOWED BY INCREASED DNA METHYLATION, SUPPORTING ITS FUNCTION AS A PRE-MARK FOR ABERRANT DNA METHYLATION. THESE RESULTS DEMONSTRATED THAT ABERRANT H3K27ME3 CAN BE INDUCED BY EXPOSURE TO A SPECIFIC ENVIRONMENT, SUCH AS COLITIS, AND SUGGESTED THAT ABERRANT HISTONE MODIFICATION, IN ADDITION TO ABERRANT DNA METHYLATION, IS INVOLVED IN THE FORMATION OF A FIELD DEFECT. 2012 20 5872 26 SUSTAINED TNF-ALPHA STIMULATION LEADS TO TRANSCRIPTIONAL MEMORY THAT GREATLY ENHANCES SIGNAL SENSITIVITY AND ROBUSTNESS. TRANSCRIPTIONAL MEMORY ALLOWS CERTAIN GENES TO RESPOND TO PREVIOUSLY EXPERIENCED SIGNALS MORE ROBUSTLY. HOWEVER, WHETHER AND HOW THE KEY PROINFLAMMATORY CYTOKINE TNF-ALPHA MEDIATES TRANSCRIPTIONAL MEMORY ARE POORLY UNDERSTOOD. USING HEK293F CELLS AS A MODEL SYSTEM, WE REPORT THAT SUSTAINED TNF-ALPHA STIMULATION INDUCES TRANSCRIPTIONAL MEMORY DEPENDENT ON TET ENZYMES. THE HYPOMETHYLATED STATUS OF TRANSCRIPTIONAL REGULATORY REGIONS CAN BE INHERITED, FACILITATING NF-KAPPAB BINDING AND MORE ROBUST SUBSEQUENT ACTIVATION. A HIGH INITIAL METHYLATION LEVEL AND CPG DENSITY AROUND KAPPAB SITES ARE CORRELATED WITH THE FUNCTIONAL POTENTIAL OF TRANSCRIPTIONAL MEMORY MODULES. INTERESTINGLY, THE CALCB GENE, ENCODING THE PROVEN MIGRAINE THERAPEUTIC TARGET CGRP, EXHIBITS THE BEST TRANSCRIPTIONAL MEMORY. A NEIGHBORING PRIMATE-SPECIFIC ENDOGENOUS RETROVIRUS STIMULATES MORE RAPID, MORE STRONG, AND AT LEAST 100-FOLD MORE SENSITIVE CALCB INDUCTION IN SUBSEQUENT TNF-ALPHA STIMULATION. OUR STUDY REVEALS THAT TNF-ALPHA-MEDIATED TRANSCRIPTIONAL MEMORY IS GOVERNED BY ACTIVE DNA DEMETHYLATION AND GREATLY SENSITIZES MEMORY GENES TO MUCH LOWER DOSES OF INFLAMMATORY CUES. 2020