1 613 119 BINGE ALCOHOL ALTERS PNPLA3 LEVELS IN LIVER THROUGH EPIGENETIC MECHANISM INVOLVING HISTONE H3 ACETYLATION. THE HUMAN PNPLA3 (PATATIN-LIKE PHOSPHOLIPASE DOMAIN-CONTAINING 3) GENE CODES FOR A PROTEIN WHICH IS HIGHLY EXPRESSED IN ADIPOSE TISSUE AND LIVER, AND IS IMPLICATED IN LIPID HOMEOSTASIS. WHILE PNPLA3 PROTEIN CONTAINS REGIONS HOMOLOGOUS TO FUNCTIONAL LIPOLYTIC PROTEINS, THE REGULATION OF ITS TISSUE EXPRESSION IS REFLECTIVE OF LIPOGENIC GENES. A NATURALLY OCCURRING GENETIC VARIANT OF PNPLA3 IN HUMANS HAS BEEN LINKED TO INCREASED SUSCEPTIBILITY TO ALCOHOLIC LIVER DISEASE. WE HAVE EXAMINED THE MODULATORY EFFECT OF ALCOHOL ON PNPLA3 PROTEIN AND MRNA EXPRESSION AS WELL AS THE ASSOCIATION OF ITS GENE PROMOTER WITH ACETYLATED HISTONE H3K9 BY CHROMATIN IMMUNOPRECIPITATION (CHIP) ASSAY IN RAT HEPATOCYTES IN VITRO, AND IN VIVO IN MOUSE AND RAT MODELS OF ACUTE BINGE, CHRONIC, AND CHRONIC FOLLOWED BY ACUTE BINGE ETHANOL ADMINISTRATION. PROTEIN EXPRESSION OF PNPLA3 WAS SIGNIFICANTLY INCREASED BY ALCOHOL IN ALL THREE MODELS USED. PNPLA3 MRNA ALSO INCREASED, ALBEIT TO A VARYING DEGREE. CHIP ASSAY USING H3ACK9 ANTIBODY SHOWED INCREASED ASSOCIATION WITH THE PROMOTER OF PNPLA3 IN HEPATOCYTES AND IN MOUSE LIVER. THIS WAS LESS EVIDENT IN RAT LIVERS IN VIVO EXCEPT UNDER CHRONIC TREATMENT. IT IS CONCLUDED FOR THE FIRST TIME THAT HISTONE ACETYLATION PLAYS A ROLE IN THE MODULATION OF PNPLA3 LEVELS IN THE LIVER EXPOSED TO BINGE ETHANOL BOTH IN VITRO AND IN VIVO. 2017 2 894 35 CHRONIC ETHANOL FEEDING ALTERS HEPATOCYTE MEMORY WHICH IS NOT ALTERED BY ACUTE FEEDING. BACKGROUND: GENE EXPRESSION CHANGES IN THE LIVER AFTER ACUTE BINGE DRINKING MAY DIFFER FROM THE CHANGES SEEN IN CHRONIC ETHANOL FEEDING IN THE RAT. THE CHANGES IN GENE EXPRESSION AFTER CHRONIC ETHANOL FEEDING MAY SENSITIZE THE LIVER TO ALCOHOL-INDUCED LIVER DAMAGE, WHICH IS NOT SEEN AFTER ACUTE BINGE DRINKING. METHODS: TO TEST THIS HYPOTHESIS, GENE MICROARRAY ANALYSIS WAS PERFORMED ON THE LIVERS OF RATS (N = 3) FED AN ACUTE BINGE DOSE OF ETHANOL (6 G/KG BODY WT) AND KILLED AT 3 AND 12 HOURS AFTER ETHANOL BY GAVAGE. THE GENE MICROARRAYS WERE COMPARED WITH THOSE MADE ON THE LIVER OF RATS FROM A PREVIOUS STUDY, IN WHICH THE RATS WERE FED ETHANOL BY INTRAGASTRIC TUBE FOR 1 MONTH (36% OF CALORIES DERIVED FROM ETHANOL). RESULTS: MICROARRAY ANALYSIS DATA VARIED BETWEEN THE ACUTE AND CHRONIC MODELS IN SEVERAL IMPORTANT RESPECTS. GROWTH FACTORS INCREASED MAINLY IN THE CHRONIC ALCOHOL FED RAT. CHANGES IN ENZYMES INVOLVED IN OXIDATIVE STRESS WERE NOTED ONLY WITH CHRONIC ETHANOL FEEDING. GENE EXPRESSION OF FAT METABOLISM WAS INCREASED ONLY WITH CHRONIC ETHANOL FEEDING. MOST IMPORTANTLY, EPIGENETIC RELATED ENZYMES AND ACETYLATION AND METHYLATION OF HISTONES CHANGED ONLY AFTER CHRONIC ETHANOL FEEDING. CONCLUSIONS: THE RESULTS SUPPORT THE CONCEPT THAT CHRONIC ETHANOL INGESTION INDUCES ALTERED GENE EXPRESSION AS A RESULT OF CHANGES IN EPIGENETIC MECHANISMS, WHERE ACETYLATION AND METHYLATION OF HISTONES WERE ALTERED. 2009 3 4768 28 NUCLEAR EFFECTS OF ETHANOL-INDUCED PROTEASOME INHIBITION IN LIVER CELLS. ALCOHOL INGESTION CAUSES ALTERATION IN SEVERAL CELLULAR MECHANISMS, AND LEADS TO INFLAMMATION, APOPTOSIS, IMMUNOLOGICAL RESPONSE DEFECTS, AND FIBROSIS. THESE PHENOMENA ARE ASSOCIATED WITH SIGNIFICANT CHANGES IN THE EPIGENETIC MECHANISMS, AND SUBSEQUENTLY, TO LIVER CELL MEMORY. THE UBIQUITIN-PROTEASOME PATHWAY IS ONE OF THE VITAL PATHWAYS IN THE CELL THAT BECOMES DYSFUNCTIONAL AS A RESULT OF CHRONIC ETHANOL CONSUMPTION. INHIBITION OF THE PROTEASOME ACTIVITY IN THE NUCLEUS CAUSES CHANGES IN THE TURNOVER OF TRANSCRIPTIONAL FACTORS, HISTONE MODIFYING ENZYMES, AND THEREFORE, AFFECTS EPIGENETIC MECHANISMS. ALCOHOL CONSUMPTION HAS BEEN ASSOCIATED WITH AN INCREASE IN HISTONE ACETYLATION AND A DECREASE IN HISTONE METHYLATION, WHICH LEADS TO GENE EXPRESSION CHANGES. DNA AND HISTONE MODIFICATIONS THAT RESULT FROM ETHANOL-INDUCED PROTEASOME INHIBITION ARE KEY PLAYERS IN REGULATING GENE EXPRESSION, ESPECIALLY GENES INVOLVED IN THE CELL CYCLE, IMMUNOLOGICAL RESPONSES, AND METABOLISM OF ETHANOL. THE PRESENT REVIEW HIGHLIGHTS THE CONSEQUENCES OF ETHANOL-INDUCED PROTEASOME INHIBITION IN THE NUCLEUS OF LIVER CELLS THAT ARE CHRONICALLY EXPOSED TO ETHANOL. 2009 4 3240 38 HEPATIC LIPID ACCUMULATION ALTERS GLOBAL HISTONE H3 LYSINE 9 AND 4 TRIMETHYLATION IN THE PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR ALPHA NETWORK. RECENT DATA SUGGEST THAT THE ETIOLOGY OF SEVERAL METABOLIC DISEASES IS CLOSELY ASSOCIATED WITH TRANSCRIPTOME ALTERATION BY ABERRANT HISTONE METHYLATION. WE PERFORMED DNA MICROARRAY AND CHIP-ON-CHIP ANALYSES TO EXAMINE TRANSCRIPTOME PROFILING AND TRIMETHYLATION ALTERATIONS TO IDENTIFY THE GENOMIC SIGNATURE OF NONALCOHOLIC FATTY LIVER DISEASE (NAFLD), THE MOST COMMON FORM OF CHRONIC LIVER DISEASE. TRANSCRIPTOME ANALYSIS SHOWED THAT STEATOTIC LIVERS IN HIGH-FAT DIET-FED APOLIPOPROTEIN E2 MICE SIGNIFICANTLY ALTERED THE EXPRESSION OF APPROXIMATELY 70% OF TOTAL GENES COMPARED WITH NORMAL DIET-FED CONTROL LIVERS, SUGGESTING THAT HEPATIC LIPID ACCUMULATION INDUCES DRAMATIC ALTERATIONS IN GENE EXPRESSION IN VIVO. ALSO, PATHWAY ANALYSIS SUGGESTED THAT GENES ENCODING CHROMATIN-REMODELING ENZYMES, SUCH AS JUMONJI C-DOMAIN-CONTAINING HISTONE DEMETHYLASES THAT REGULATE HISTONE H3K9 AND H3K4 TRIMETHYLATION (H3K9ME3, H3K4ME3), WERE SIGNIFICANTLY ALTERED IN STEATOTIC LIVERS. THUS, WE FURTHER INVESTIGATED THE GLOBAL H3K9ME3 AND H3K4ME3 STATUS IN LIPID-ACCUMULATED MOUSE PRIMARY HEPATOCYTES BY CHIP-ON-CHIP ANALYSIS. RESULTS SHOWED THAT HEPATIC LIPID ACCUMULATION INDUCED ABERRANT H3K9ME3 AND H3K4ME3 STATUS IN PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR ALPHA AND HEPATIC LIPID CATABOLISM NETWORK GENES, REDUCING THEIR MRNA EXPRESSION COMPARED WITH NON-TREATED CONTROL HEPATOCYTES. THIS STUDY PROVIDES THE FIRST EVIDENCE THAT EPIGENETIC REGULATION BY H3K9ME3 AND H3K4ME3 IN HEPATOCYTES MAY BE INVOLVED IN HEPATIC STEATOSIS AND THE PATHOGENESIS OF NAFLD. THUS, CONTROL OF H3K9ME3 AND H3K4ME3 REPRESENTS A POTENTIAL NOVEL NAFLD PREVENTION AND TREATMENT STRATEGY. 2012 5 1731 41 DYSREGULATION OF THE HISTONE DEMETHYLASE KDM6B IN ALCOHOL DEPENDENCE IS ASSOCIATED WITH EPIGENETIC REGULATION OF INFLAMMATORY SIGNALING PATHWAYS. EPIGENETIC ENZYMES OVERSEE LONG-TERM CHANGES IN GENE EXPRESSION BY INTEGRATING GENETIC AND ENVIRONMENTAL CUES. WHILE THERE ARE HUNDREDS OF ENZYMES THAT CONTROL HISTONE AND DNA MODIFICATIONS, THEIR POTENTIAL ROLES IN SUBSTANCE ABUSE AND ALCOHOL DEPENDENCE REMAIN UNDEREXPLORED. A FEW RECENT STUDIES HAVE SUGGESTED THAT EPIGENETIC PROCESSES COULD UNDERLIE TRANSCRIPTOMIC AND BEHAVIORAL HALLMARKS OF ALCOHOL ADDICTION. IN THE PRESENT STUDY, WE SOUGHT TO IDENTIFY EPIGENETIC ENZYMES IN THE BRAIN THAT ARE DYSREGULATED DURING PROTRACTED ABSTINENCE AS A CONSEQUENCE OF CHRONIC AND INTERMITTENT ALCOHOL EXPOSURE. THROUGH QUANTITATIVE MRNA EXPRESSION ANALYSIS OF OVER 100 EPIGENETIC ENZYMES, WE IDENTIFIED 11 THAT ARE SIGNIFICANTLY ALTERED IN ALCOHOL-DEPENDENT RATS COMPARED WITH CONTROLS. FOLLOW-UP STUDIES OF ONE OF THESE ENZYMES, THE HISTONE DEMETHYLASE KDM6B, SHOWED THAT THIS ENZYME EXHIBITS REGION-SPECIFIC DYSREGULATION IN THE PREFRONTAL CORTEX AND NUCLEUS ACCUMBENS OF ALCOHOL-DEPENDENT RATS. KDM6B WAS ALSO UPREGULATED IN THE HUMAN ALCOHOLIC BRAIN. UPREGULATION OF KDM6B PROTEIN IN ALCOHOL-DEPENDENT RATS WAS ACCOMPANIED BY A DECREASE OF TRIMETHYLATION LEVELS AT HISTONE H3, LYSINE 27 (H3K27ME3), CONSISTENT WITH THE KNOWN DEMETHYLASE SPECIFICITY OF KDM6B. SUBSEQUENT EPIGENETIC (CHROMATIN IMMUNOPRECIPITATION [CHIP]-SEQUENCING) ANALYSIS SHOWED THAT ALCOHOL-INDUCED CHANGES IN H3K27ME3 WERE SIGNIFICANTLY ENRICHED AT GENES IN THE IL-6 SIGNALING PATHWAY, CONSISTENT WITH THE WELL-CHARACTERIZED ROLE OF KDM6B IN MODULATION OF INFLAMMATORY RESPONSES. KNOCKDOWN OF KDM6B IN CULTURED MICROGLIAL CELLS DIMINISHED IL-6 INDUCTION IN RESPONSE TO AN INFLAMMATORY STIMULUS. OUR FINDINGS IMPLICATE A NOVEL KDM6B-MEDIATED EPIGENETIC SIGNALING PATHWAY INTEGRATED WITH INFLAMMATORY SIGNALING PATHWAYS THAT ARE KNOWN TO UNDERLIE THE DEVELOPMENT OF ALCOHOL ADDICTION. 2021 6 5438 25 REMOVAL OF EPIGENETIC REPRESSIVE MARK ON INFLAMMATORY GENES IN FAT LIVER. NONALCOHOLIC FATTY LIVER DISEASE (NAFLD) IS THE MOST COMMON CHRONIC LIVER DISEASE WORLDWIDE. THE DETAILED EPIGENOMIC CHANGES DURING FAT ACCUMULATION IN LIVER ARE NOT CLEAR YET. HERE, WE PERFORMED CHIP-SEQ ANALYSIS IN THE LIVER TISSUES OF HIGH-FAT DIET AND REGULAR CHOW DIET MICE AND INVESTIGATED THE DYNAMIC LANDSCAPES OF H3K27AC AND H3K9ME3 MARKS ON CHROMATIN. WE FIND THAT THE ACTIVATED TYPICAL ENHANCERS MARKED WITH H3K27AC ARE ENRICHED ON LIPID METABOLIC PATHWAYS IN FAT LIVER; HOWEVER, SUPER ENHANCERS DO NOT CHANGE MUCH. THE REGIONS COVERED WITH H3K9ME3 REPRESSIVE MARK SEEM TO UNDERGO GREAT CHANGES, AND ITS PEAK NUMBER AND INTENSITY BOTH DECREASE IN FAT LIVER. THE ENHANCERS LOCATED IN LOST H3K9ME3 REGIONS ARE ENRICHED IN LIPID METABOLISM AND INFLAMMATORY PATHWAYS; AND MOTIF ANALYSIS SHOWS THAT THEY ARE POTENTIAL TARGETS FOR TRANSCRIPTION FACTORS INVOLVED IN METABOLIC AND INFLAMMATORY PROCESSES. OUR STUDY HAS REVEALED THAT H3K9ME3 MAY PLAY AN IMPORTANT ROLE DURING THE PATHOGENESIS OF NAFLD THROUGH REGULATING THE ACCESSIBILITY OF ENHANCERS. 2023 7 2780 37 EZH2 DOWN-REGULATION EXACERBATES LIPID ACCUMULATION AND INFLAMMATION IN IN VITRO AND IN VIVO NAFLD. NON-ALCOHOLIC FATTY LIVER DISEASE (NAFLD) IS ONE OF THE MOST PREVALENT, CHRONIC LIVER DISEASES, WORLDWIDE. IT IS A MULTIFACTORIAL DISEASE CAUSED BY COMPLEX INTERACTIONS BETWEEN GENETIC, EPIGENETIC AND ENVIRONMENTAL FACTORS. RECENTLY, SEVERAL MICRORNAS, SOME OF WHICH EPIGENETICALLY REGULATED, HAVE BEEN FOUND TO BE UP- AND/OR DOWN-REGULATED DURING NAFLD DEVELOPMENT. HOWEVER, IN NAFLD, THE ESSENTIAL ROLE OF THE POLYCOMB GROUP PROTEIN ENHANCER OF ZESTE HOMOLOG 2 (EZH2), WHICH CONTROLS THE EPIGENETIC SILENCING OF SPECIFIC GENES AND/OR MICRORNAS BY TRIMETHYLATING LYS27 ON HISTONE H3, STILL REMAINS UNKNOWN. IN THIS STUDY, WE DEMONSTRATE THAT THE NUCLEAR EXPRESSION/ACTIVITY OF THE EZH2 PROTEIN IS DOWN-REGULATED BOTH IN LIVERS FROM NAFLD RATS AND IN THE FREE FATTY ACID-TREATED HEPG2. THE DROP IN EZH2 IS INVERSELY CORRELATED WITH: (I) LIPID ACCUMULATION; (II) THE EXPRESSION OF PRO-INFLAMMATORY MARKERS INCLUDING TNF-ALPHA AND TGF-BETA; AND (III) THE EXPRESSION OF MIR-200B AND MIR-155. CONSISTENTLY, THE PHARMACOLOGICAL INHIBITION OF EZH2 BY 3-DEAZANEPLANOCIN A (DZNEP) SIGNIFICANTLY REDUCES EZH2 EXPRESSION/ACTIVITY, WHILE IT INCREASES LIPID ACCUMULATION, INFLAMMATORY MOLECULES AND MICRORNAS. IN CONCLUSION, THE RESULTS OF THIS STUDY SUGGEST THAT THE DEFECTIVE ACTIVITY OF EZH2 CAN ENHANCE THE NAFLD DEVELOPMENT BY FAVOURING STEATOSIS AND THE DE-REPRESSION OF THE INFLAMMATORY GENES AND THAT OF SPECIFIC MICRORNAS. 2013 8 2590 36 EPIGENETICS OF PROTEASOME INHIBITION IN THE LIVER OF RATS FED ETHANOL CHRONICALLY. AIM: TO EXAMINE THE EFFECTS OF ETHANOL-INDUCED PROTEASOME INHIBITION, AND THE EFFECTS OF PROTEASOME INHIBITION IN THE REGULATION OF EPIGENETIC MECHANISMS. METHODS: RATS WERE FED ETHANOL FOR 1 MO USING THE TSUKAMOTO-FRENCH MODEL AND WERE COMPARED TO RATS GIVEN THE PROTEASOME INHIBITOR PS-341 (BORTEZOMIB, VELCADE(TM)) BY INTRAPERITONEAL INJECTION. MICROARRAY ANALYSIS AND REAL TIME PCR WERE PERFORMED AND PROTEASOME ACTIVITY ASSAYS AND WESTERN BLOT ANALYSIS WERE PERFORMED USING ISOLATED NUCLEI. RESULTS: CHRONIC ETHANOL FEEDING CAUSED A SIGNIFICANT INHIBITION OF THE UBIQUITIN PROTEASOME PATHWAY IN THE NUCLEUS, WHICH LED TO CHANGES IN THE TURNOVER OF TRANSCRIPTIONAL FACTORS, HISTONE-MODIFYING ENZYMES, AND, THEREFORE, AFFECTED EPIGENETIC MECHANISMS. CHRONIC ETHANOL FEEDING WAS RELATED TO AN INCREASE IN HISTONE ACETYLATION, AND IT IS HYPOTHESIZED THAT THE PROTEASOME PROTEOLYTIC ACTIVITY REGULATED HISTONE MODIFICATIONS BY CONTROLLING THE STABILITY OF HISTONE MODIFYING ENZYMES, AND, THEREFORE, REGULATED THE CHROMATIN STRUCTURE, ALLOWING EASY ACCESS TO CHROMATIN BY RNA POLYMERASE, AND, THUS, PROPER GENE EXPRESSION. PROTEASOME INHIBITION BY PS-341 INCREASED HISTONE ACETYLATION SIMILAR TO CHRONIC ETHANOL FEEDING. IN ADDITION, PROTEASOME INHIBITION CAUSED DRAMATIC CHANGES IN HEPATIC REMETHYLATION REACTIONS AS THERE WAS A SIGNIFICANT DECREASE IN THE ENZYMES RESPONSIBLE FOR THE REGENERATION OF S-ADENOSYLMETHIONINE, AND, IN PARTICULAR, A SIGNIFICANT DECREASE IN THE BETAINE-HOMOCYSTEINE METHYLTRANSFERASE ENZYME. THIS SUGGESTED THAT HYPOMETHYLATION WAS ASSOCIATED WITH PROTEASOME INHIBITION, AS INDICATED BY THE DECREASE IN HISTONE METHYLATION. CONCLUSION: THE ROLE OF PROTEASOME INHIBITION IN REGULATING EPIGENETIC MECHANISMS, AND ITS LINK TO LIVER INJURY IN ALCOHOLIC LIVER DISEASE, IS THUS A PROMISING APPROACH TO STUDY LIVER INJURY DUE TO CHRONIC ETHANOL CONSUMPTION. 2009 9 4215 29 METHYL DEFICIENCY, ALTERATIONS IN GLOBAL HISTONE MODIFICATIONS, AND CARCINOGENESIS. THE METHYL-DEFICIENT MODEL OF ENDOGENOUS HEPATOCARCINOGENESIS IN RODENTS IS UNIQUE IN THAT DIETARY OMISSION RATHER THAN THE ADDITION OF CHEMICAL CARCINOGENS LEADS TO TUMOR FORMATION. THUS, THE BIOCHEMICAL AND MOLECULAR EVENTS PREDISPOSING TO CANCER IN THIS MODEL RESULT FROM CHRONIC METABOLIC STRESS AND PROVIDE AN IDEAL MODEL SYSTEM TO STUDY PROGRESSIVE ALTERATIONS THAT OCCUR DURING CARCINOGENESIS. MOREOVER, EPIGENETIC ALTERATIONS IMPOSED BY THIS DIET ARE BELIEVED TO BE 1 OF THE MAIN MECHANISMS RESPONSIBLE FOR MALIGNANT TRANSFORMATION OF RAT LIVER CELLS. IN THIS STUDY WE EXAMINED THE CHANGES IN GLOBAL HISTONE MODIFICATION PATTERNS IN LIVER DURING HEPATOCARCINOGENESIS INDUCED BY METHYL DEFICIENCY. FEEDING ANIMALS THE METHYL-DEFICIENT DIET (MDD) LED TO PROGRESSIVE LOSS OF HISTONE H4 LYSINE 20 TRIMETHYLATION (H4K20ME3), H3 LYSINE 9 TRIMETHYLATION (H3K9ME3), AND HISTONE H3 LYSINE 9 (H3K9AC) AND HISTONE H4 LYSINE 16 (H4K16AC) ACETYLATION. A CONSIDERABLE DECREASE OF H4K20ME3 AND H3K9AC WAS ALSO DETECTED IN LIVER TUMORS INDUCED BY MDD. IN CONTRAST, LIVER TUMORS DISPLAYED AN INCREASE IN H3K9ME3 AND H4K16AC. TO DETERMINE THE POSSIBLE MECHANISM OF ALTERATIONS OF HISTONE MODIFICATIONS, WE ANALYZED THE EXPRESSION OF HISTONE-MODIFYING ENZYMES IN LIVER DURING HEPATOCARCINOGENESIS. THE EXPRESSION OF SUV4-20H2 AND RIZ1 HISTONE METHYLTRANSFERASES (HMTS) STEADILY DECREASED ALONG WITH THE DEVELOPMENT OF LIVER TUMORS AND REACHED ITS LOWEST LEVEL IN TUMOR TISSUE, WHEREAS THE EXPRESSION OF SUV39-H1 HMT AND HISTONE ACETYLTRANSFERASE 1 (HAT1) SUBSTANTIALLY INCREASED IN TUMORS. THESE RESULTS ILLUSTRATE THE COMPLEXITY AND IMPORTANCE OF HISTONE MODIFICATION CHANGES IN THE ETIOLOGY OF HEPATOCARCINOGENESIS INDUCED BY MDD. 2007 10 5177 40 PREFRONTAL CORTEX EXPRESSION OF CHROMATIN MODIFIER GENES IN MALE WSP AND WSR MICE CHANGES ACROSS ETHANOL DEPENDENCE, WITHDRAWAL, AND ABSTINENCE. ALCOHOL-USE DISORDER (AUD) IS A RELAPSING DISORDER ASSOCIATED WITH EXCESSIVE ETHANOL CONSUMPTION. RECENT STUDIES SUPPORT THE INVOLVEMENT OF EPIGENETIC MECHANISMS IN THE DEVELOPMENT OF AUD. STUDIES CARRIED OUT SO FAR HAVE FOCUSED ON A FEW SPECIFIC EPIGENETIC MODIFICATIONS. THE GOAL OF THIS PROJECT WAS TO INVESTIGATE GENE EXPRESSION CHANGES OF EPIGENETIC REGULATORS THAT MEDIATE A BROAD ARRAY OF CHROMATIN MODIFICATIONS AFTER CHRONIC ALCOHOL EXPOSURE, CHRONIC ALCOHOL EXPOSURE FOLLOWED BY 8 H WITHDRAWAL, AND CHRONIC ALCOHOL EXPOSURE FOLLOWED BY 21 DAYS OF ABSTINENCE IN WITHDRAWAL-RESISTANT (WSR) AND WITHDRAWAL SEIZURE-PRONE (WSP) SELECTED MOUSE LINES. WE FOUND THAT CHRONIC VAPOR EXPOSURE TO HIGHLY INTOXICATING LEVELS OF ETHANOL ALTERS THE EXPRESSION OF SEVERAL CHROMATIN REMODELING GENES MEASURED BY QUANTITATIVE PCR ARRAY ANALYSES. THE IDENTIFIED EFFECTS WERE INDEPENDENT OF SELECTED LINES, WHICH, HOWEVER, DISPLAYED BASELINE DIFFERENCES IN EPIGENETIC GENE EXPRESSION. WE REPORTED DYSREGULATION IN THE EXPRESSION OF GENES INVOLVED IN HISTONE ACETYLATION, DEACETYLATION, LYSINE AND ARGININE METHYLATION AND UBIQUITINATIONHYLATION DURING CHRONIC ETHANOL EXPOSURE AND WITHDRAWAL, BUT NOT AFTER 21 DAYS OF ABSTINENCE. ETHANOL-INDUCED CHANGES ARE CONSISTENT WITH DECREASED HISTONE ACETYLATION AND WITH DECREASED DEPOSITION OF THE PERMISSIVE UBIQUITINATION MARK H2BK120UB, ASSOCIATED WITH REDUCED TRANSCRIPTION. ON THE OTHER HAND, ETHANOL-INDUCED CHANGES IN THE EXPRESSION OF GENES INVOLVED IN HISTONE LYSINE METHYLATION ARE CONSISTENT WITH INCREASED TRANSCRIPTION. THE NET RESULT OF THESE MODIFICATIONS ON GENE EXPRESSION IS LIKELY TO DEPEND ON THE COMBINATION OF THE SPECIFIC HISTONE TAIL MODIFICATIONS PRESENT AT A GIVEN TIME ON A GIVEN PROMOTER. SINCE ALCOHOL DOES NOT MODULATE GENE EXPRESSION UNIDIRECTIONALLY, IT IS NOT SURPRISING THAT ALCOHOL DOES NOT UNIDIRECTIONALLY ALTER CHROMATIN STRUCTURE TOWARD A CLOSED OR OPEN STATE, AS SUGGESTED BY THE RESULTS OF THIS STUDY. 2017 11 4173 39 MELATONIN INDUCES HISTONE HYPERACETYLATION IN THE RAT BRAIN. WE HAVE REPORTED THAT MELATONIN INDUCES HISTONE HYPERACETYLATION IN MOUSE NEURAL STEM CELLS, SUGGESTING AN EPIGENETIC ROLE FOR THIS PLEIOTROPIC HORMONE. TO SUPPORT SUCH A ROLE, IT IS NECESSARY TO DEMONSTRATE THAT MELATONIN PRODUCES SIMILAR EFFECTS IN VIVO. HISTONE ACETYLATION, FOLLOWING CHRONIC TREATMENT WITH MELATONIN (4MUG/ML IN DRINKING WATER FOR 17 DAYS), WAS EXAMINED BY WESTERN BLOTTING IN SELECTED RAT BRAIN REGIONS. MELATONIN INDUCED SIGNIFICANT INCREASES IN HISTONE H3 AND HISTONE H4 ACETYLATION IN THE HIPPOCAMPUS. HISTONE H4 WAS ALSO HYPERACETYLATED IN THE STRIATUM, BUT THERE WERE NO SIGNIFICANT CHANGES IN HISTONE H3 ACETYLATION IN THIS BRAIN REGION. NO SIGNIFICANT CHANGES IN THE ACETYLATION OF EITHER HISTONE H3 OR H4 WERE OBSERVED IN THE MIDBRAIN AND CEREBELLUM. AN EXAMINATION OF KINASE ACTIVATION, WHICH MAY BE RELATED TO THESE CHANGES, REVEALED THAT MELATONIN TREATMENT INCREASED THE LEVELS OF PHOSPHO-ERK (EXTRACELLULAR SIGNAL-REGULATED KINASE) IN THE HIPPOCAMPUS AND STRIATUM, BUT PHOSPHO-AKT (PROTEIN KINASE B) LEVELS WERE UNCHANGED. THESE FINDINGS SUGGEST THAT CHROMATIN REMODELING AND ASSOCIATED CHANGES IN THE EPIGENETIC REGULATION OF GENE EXPRESSION UNDERLIE THE MULTIPLE PHYSIOLOGICAL EFFECTS OF MELATONIN. 2013 12 6801 52 [EPIGENETIC MECHANISMS AND ALCOHOL USE DISORDERS: A POTENTIAL THERAPEUTIC TARGET]. ALCOHOL USE DISORDER IS A DEVASTATING ILLNESS WITH A PROFOUND HEALTH IMPACT, AND ITS DEVELOPMENT IS DEPENDENT ON BOTH GENETIC AND ENVIRONMENTAL FACTORS. THIS DISEASE OCCURS OVER TIME AND REQUIRES CHANGES IN BRAIN GENE EXPRESSION. THERE IS CONVERGING EVIDENCE SUGGESTING THAT THE EPIGENETIC PROCESSES MAY PLAY A ROLE IN THE ALCOHOL-INDUCED GENE REGULATIONS AND BEHAVIOR SUCH AS THE INTERVENTION OF DNA METHYLATION AND HISTONE ACETYLATION. HISTONE ACETYLATION, LIKE HISTONE METHYLATION, IS A HIGHLY DYNAMIC PROCESS REGULATED BY TWO CLASSES OF ENZYMES: HISTONE ACETYLTRANSFERASES AND HISTONE DEACETYLASES (HDACS). TO DATE, 18 HUMAN HDAC ISOFORMS HAVE BEEN CHARACTERIZED, AND BASED ON THEIR SEQUENCE HOMOLOGIES AND COFACTOR DEPENDENCIES, THEY HAVE BEEN PHYLOGENETICALLY CATEGORIZED INTO 4 MAIN CLASSES: CLASSES I, II (A AND B), III, AND IV. IN THE BRAIN, EXPRESSION OF THE DIFFERENT CLASSES OF HDACS VARIES BETWEEN CELL TYPES AND ALSO IN THEIR SUBCELLULAR LOCALIZATION (NUCLEUS AND/OR CYTOSOL). FURTHERMORE, WE RECENTLY SHOWED THAT A SINGLE ETHANOL EXPOSURE INHIBITS HDAC ACTIVITY AND INCREASES BOTH H3 AND H4 HISTONE ACETYLATION WITHIN THE AMYGDALA OF RATS. IN THE BRAIN OF ALCOHOLIC PATIENTS, ETHANOL HAS BEEN SHOWN TO INDUCE HISTONE-RELATED AND DNA METHYLATION EPIGENETIC CHANGES IN SEVERAL REWARD REGIONS INVOLVED IN REWARD PROCESSES SUCH AS HIPPOCAMPUS, PREFRONTAL CORTEX, AND AMYGDALA. WE RECENTLY DEMONSTRATED ALTERATION OF HISTONE H3 ACETYLATION LEVELS IN SEVERAL BRAIN REGIONS FROM THE REWARD CIRCUIT OF RATS MADE DEPENDENT TO ALCOHOL AFTER CHRONIC AND INTERMITTENT EXPOSURE TO ETHANOL VAPOR. IN NEURONAL CELL LINE CULTURE, ETHANOL WAS SHOWN TO INDUCE HDAC EXPRESSION. IN MOUSE AND RAT BRAIN, NUMEROUS STUDIES REPORTED EPIGENETIC ALTERATIONS FOLLOWING ETHANOL EXPOSURE. WE ALSO DEMONSTRATED THAT BOTH THE EXPRESSION OF GENES AND THE ACTIVITY OF ENZYMES INVOLVED IN EPIGENETIC MECHANISMS ARE CHANGED AFTER REPEATED ADMINISTRATIONS OF ETHANOL IN MICE SENSITIZED TO THE MOTOR STIMULANT EFFECT OF ETHANOL (A MODEL OF DRUG-INDUCED NEUROPLASTICITY). NUMEROUS STUDIES HAVE SHOWN THAT HDAC INHIBITORS ARE ABLE TO COUNTER ETHANOL-INDUCED BEHAVIORS AND THE ETHANOL-INDUCED CHANGES IN THE LEVELS OF HDAC AND/OR LEVELS OF ACETYLATED HDAC. FOR EXAMPLE, TRICHOSTATIN A (TSA) TREATMENT CAUSED THE REVERSAL OF ETHANOL-INDUCED TOLERANCE, ANXIETY, AND ETHANOL DRINKING BY INHIBITING HDAC ACTIVITY, THEREBY INCREASING HISTONE ACETYLATION IN THE AMYGDALA OF RATS. ANOTHER STUDY DEMONSTRATED THAT TSA PREVENTED THE DEVELOPMENT OF ETHANOL WITHDRAWAL INDUCED ANXIETY IN RATS BY RESCUING DEFICITS IN HISTONE ACETYLATION INDUCED BY INCREASED HDAC ACTIVITY IN THE AMYGDALA. WE HAVE DEMONSTRATED THAT TREATMENT WITH THE HDAC INHIBITOR SODIUM BUTYRATE BLOCKS BOTH THE DEVELOPMENT AND THE EXPRESSION OF ETHANOL-INDUCED BEHAVIORAL SENSITIZATION IN MICE. IN THIS CONTEXT, CONVERGING EVIDENCE INDICATES THAT HDAC INHIBITORS COULD BE USEFUL IN COUNTERACTING ETHANOL-INDUCED GENE REGULATIONS VIA EPIGENETIC MECHANISMS, THAT IS, HDAC INHIBITORS COULD AFFECT DIFFERENT ACETYLATION SITES AND MAY ALSO ALTER THE EXPRESSION OF DIFFERENT GENES THAT COULD IN TURN COUNTERACT THE EFFECT OF ETHANOL. RECENT WORK IN RODENTS HAS SHOWN THAT SYSTEMIC ADMINISTRATION OF PAN HDAC CLASS I AND II INHIBITORS, TSA AND N-HYDROXY-N-PHENYL-OCTANEDIAMIDE [SUBEROYLANILIDE HYDROXAMIC ACID] (SAHA), AND OF THE MORE SELECTIVE INHIBITOR (MAINLY HDAC1 AND HDAC9) MS-275, DECREASE BINGE-LIKE ALCOHOL DRINKING IN MICE. SAHA SELECTIVELY REDUCED ETHANOL OPERANT SELF-ADMINISTRATION AND SEEKING IN RATS. OUR PREVIOUS STUDY REVEALED THAT MS-275 STRONGLY DECREASED OPERANT ETHANOL SELF-ADMINISTRATION IN ALCOHOL-DEPENDENT RATS WHEN ADMINISTERED 30 MINUTES BEFORE THE SESSION AT THE SECOND DAY OF INJECTION. WE ALSO DEMONSTRATED THAT INTRA-CEREBRO-VENTRICULAR INFUSION OF MS-275 INCREASES ACETYLATION OF HISTONE 4 WITHIN THE NUCLEUS ACCUMBENS AND THE DORSOLATERAL STRIATUM, ASSOCIATED TO A DECREASE IN ETHANOL SELF-ADMINISTRATION BY ABOUT 75%. MS-275 ALSO DIMINISHED BOTH THE MOTIVATION TO CONSUME ETHANOL (25% DECREASE), RELAPSE (BY ABOUT 50%) AND POSTPONED REACQUISITION AFTER ABSTINENCE. BOTH LITERATURE AND SEVERAL OF OUR STUDIES STRONGLY SUPPORT THE POTENTIAL THERAPEUTIC INTEREST OF TARGETING EPIGENETIC MECHANISMS IN EXCESSIVE ALCOHOL DRINKING AND STRENGTHEN THEINTEREST OF FOCUSING ON SPECIFIC ISOFORMS OF HISTONE DEACETYLASES. 2017 13 5279 30 PROMOTER-SPECIFIC RELEVANCE OF HISTONE MODIFICATIONS INDUCED BY DEXAMETHASONE DURING THE REGULATION OF PRO-INFLAMMATORY MEDIATORS. GLUCOCORTICOSTEROIDS (GCS) ARE WIDELY USED TO TREAT DIFFERENT KINDS OF CHRONIC INFLAMMATORY AND IMMUNE DISEASES THROUGH TRANSCRIPTIONAL REGULATION OF INFLAMMATORY GENES. MODULATION OF GENE EXPRESSION BY GCS IS KNOWN TO OCCUR THROUGH DIVERSE MECHANISMS OF VARYING RELEVANCE TO SPECIFIC CLASSES OF GENES. EPIGENETIC MODIFICATIONS ARE INDEED A PIVOTAL REGULATORY FEATURE OF GLUCOCORTICOID RECEPTOR AND OTHER TRANSCRIPTION FACTORS. IN THIS STUDY, HISTONE POST-TRANSLATIONAL MODIFICATIONS WERE INVESTIGATED FOR THEIR INVOLVEMENT IN THE REGULATION OF SELECTED PRO-INFLAMMATORY GENES - EXPRESSED IN HUMAN MONOCYTE-DERIVED MACROPHAGES - IN RESPONSE TO TREATMENT WITH SYNTHETIC GC DEXAMETHASONE (DEX). WE SHOW THAT HISTONE TAIL ACETYLATION STATUS IS MODIFIED FOLLOWING DEX ADMINISTRATION, THROUGH DISTINCT AND ALTERNATIVE MECHANISMS AT THE PROMOTERS OF INTERLEUKIN-8 AND INTERLEUKIN-23. IN ADDITION TO HISTONE H3 ACETYLATION, OUR RESULTS DEMONSTRATE THAT H3 LYSINE 4 TRIMETHYLATION IS AFFECTED FOLLOWING DRUG TREATMENT. 2014 14 2104 36 EPIGENETIC EVENTS IN LIVER CANCER RESULTING FROM ALCOHOLIC LIVER DISEASE. EPIGENETIC MECHANISMS PLAY AN EXTENSIVE ROLE IN THE DEVELOPMENT OF LIVER CANCER (I.E., HEPATOCELLULAR CARCINOMA [HCC]) ASSOCIATED WITH ALCOHOLIC LIVER DISEASE (ALD) AS WELL AS IN LIVER DISEASE ASSOCIATED WITH OTHER CONDITIONS. FOR EXAMPLE, EPIGENETIC MECHANISMS, SUCH AS CHANGES IN THE METHYLATION AND/OR ACETYLATION PATTERN OF CERTAIN DNA REGIONS OR OF THE HISTONE PROTEINS AROUND WHICH THE DNA IS WRAPPED, CONTRIBUTE TO THE REVERSION OF NORMAL LIVER CELLS INTO PROGENITOR AND STEM CELLS THAT CAN DEVELOP INTO HCC. CHRONIC EXPOSURE TO BEVERAGE ALCOHOL (I.E., ETHANOL) CAN INDUCE ALL OF THESE EPIGENETIC CHANGES. THUS, ETHANOL METABOLISM RESULTS IN THE FORMATION OF COMPOUNDS THAT CAN CAUSE CHANGES IN DNA METHYLATION AND INTERFERE WITH OTHER COMPONENTS OF THE NORMAL PROCESSES REGULATING DNA METHYLATION. ALCOHOL EXPOSURE ALSO CAN ALTER HISTONE ACETYLATION/DEACETYLATION AND METHYLATION PATTERNS THROUGH A VARIETY OF MECHANISMS AND SIGNALING PATHWAYS. ALCOHOL ALSO ACTS INDIRECTLY ON ANOTHER MOLECULE CALLED TOLL-LIKE RECEPTOR 4 (TLR4) THAT IS A KEY COMPONENT IN A CRUCIAL REGULATORY PATHWAY IN THE CELLS AND WHOSE DYSREGULATION IS INVOLVED IN THE DEVELOPMENT OF HCC. FINALLY, ALCOHOL USE REGULATES AN EPIGENETIC MECHANISM INVOLVING SMALL MOLECULES CALLED MIRNAS THAT CONTROL TRANSCRIPTIONAL EVENTS AND THE EXPRESSION OF GENES IMPORTANT TO ALD. 2013 15 318 36 ALCOHOL-INDUCED EPIGENETIC CHANGES IN CANCER. CHRONIC, HEAVY ALCOHOL CONSUMPTION IS ASSOCIATED WITH SERIOUS NEGATIVE HEALTH EFFECTS, INCLUDING THE DEVELOPMENT OF SEVERAL CANCER TYPES. ONE OF THE PATHWAYS AFFECTED BY ALCOHOL TOXICITY IS THE ONE-CARBON METABOLISM. THE ALCOHOL-INDUCED IMPAIRMENT OF THIS METABOLIC PATHWAY RESULTS IN EPIGENETIC CHANGES ASSOCIATED WITH CANCER DEVELOPMENT. THESE EPIGENETIC CHANGES ARE INDUCED BY FOLATE DEFICIENCY AND BY PRODUCTS OF THE ETHANOL METABOLISM. THE CHANGES INDUCED BY LONG-TERM HEAVY ETHANOL CONSUMPTION RESULT IN ELEVATIONS OF HOMOCYSTEINE AND S-ADENOSYL-HOMOCYSTEINE (SAH) AND REDUCTIONS IN S-ADENOSYLMETHIONINE (SAM) AND ANTIOXIDANT GLUTATHIONE (GSH) LEVELS, LEADING TO ABNORMAL PROMOTER GENE HYPERMETHYLATION, GLOBAL HYPOMETHYLATION, AND METABOLIC INSUFFICIENCY OF ANTIOXIDANT DEFENSE MECHANISMS. IN ADDITION, REACTIVE OXYGEN SPECIES (ROS) GENERATED DURING THE ETHANOL METABOLISM INDUCE ALTERATIONS IN DNA METHYLATION PATTERNS THAT PLAY A CRITICAL ROLE IN CANCER DEVELOPMENT. SPECIFIC EPIGENETIC CHANGES IN ESOPHAGEAL, HEPATIC, AND COLORECTAL CANCERS HAVE BEEN DETECTED IN BLOOD SAMPLES AND PROPOSED TO BE USED CLINICALLY AS EPIGENETIC BIOMARKERS FOR DIAGNOSIS AND PROGNOSIS OF THESE CANCERS. ALSO, GENETIC VARIANTS OF GENES INVOLVED IN ONE-CARBON METABOLISM AND ETHANOL METABOLISM WERE FOUND TO MODULATE THE RELATIONSHIP BETWEEN ALCOHOL-INDUCED EPIGENETIC CHANGES AND CANCER RISK. FURTHERMORE, ALCOHOL METABOLISM PRODUCTS HAVE BEEN ASSOCIATED WITH AN INCREASE IN NADH LEVELS, WHICH LEAD TO HISTONE MODIFICATIONS AND CHANGES IN GENE EXPRESSION THAT IN TURN INFLUENCE CANCER SUSCEPTIBILITY. CHRONIC EXCESSIVE USE OF ALCOHOL ALSO AFFECTS SELECTED MEMBERS OF THE FAMILY OF MICRORNAS, AND AS MIRNAS COULD ACT AS EPIGENETIC REGULATORS, THIS MAY PLAY AN IMPORTANT ROLE IN CARCINOGENESIS. IN CONCLUSION, TARGETING ALCOHOL-INDUCED EPIGENETIC CHANGES IN SEVERAL CANCER TYPES COULD MAKE AVAILABLE CLINICAL TOOLS FOR THE DIAGNOSIS, PROGNOSIS, AND TREATMENT OF THESE CANCERS, WITH AN IMPORTANT ROLE IN PRECISION MEDICINE. 2018 16 2417 28 EPIGENETIC SIGNATURE OF CHRONIC CEREBRAL HYPOPERFUSION AND BENEFICIAL EFFECTS OF S-ADENOSYLMETHIONINE IN RATS. CHRONIC CEREBRAL HYPOPERFUSION IS ASSOCIATED WITH COGNITIVE DECLINE IN AGING AND AGE-RELATED NEURODEGENERATIVE DISEASE. EPIGENETIC MECHANISMS ARE INVOLVED IN THE MAINTENANCE OF LONG-TERM HYPOXIA-ADAPTED CELLULAR PHENOTYPES. IN THE PRESENT STUDY, THE EPIGENETIC SIGNATURES SUCH AS DNA METHYLATION AND HISTONE ACETYLATION, AS WELL AS S-ADENOSYLMETHIONINE (SAM) CYCLE USING CHRONIC CEREBRAL HYPOPERFUSION RAT MODEL WERE EXPLORED. CHRONIC CEREBRAL HYPOXIA-INDUCED GLOBAL DNA HYPERMETHYLATION ASSOCIATED WITH THE INCREASE OF DNA METHYLTRANSFERASE (DNMT) 3A AS WELL AS ALTERATION OF SAM CYCLE. MEANWHILE, AN ENHANCED LEVEL OF GLOBAL HISTONE H4 ACETYLATION ACCOMPANIED WITH THE UPREGULATION OF HISTONE ACETYLTRANSFERASE, P300/CREB-BINDING PROTEIN (CBP), AND THE DOWNREGULATION OF HISTONE DEACETYLASES (HDACS), WAS ALSO OBSERVED. SAM COULD IMPROVE SPATIAL CAPACITY THROUGH THE UPREGULATION OF ACETYLCHOLINE AND BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) RATHER THAN ALTERATION OF DNA METHYLATION LEVELS. IN CONCLUSION, WE HAVE DEMONSTRATED A GENOME-WIDE ADJUSTMENT OF DNA METHYLATION AND HISTONE ACETYLATION UNDER CHRONIC CEREBRAL HYPOXIC CONDITIONS IN A RAT'S BRAIN. THESE EPIGENETIC SIGNATURES MAY REPRESENT AN ADDITIONAL MECHANISM TO PROMOTE AND MAINTAIN A HYPOXIC-ADAPTED CELLULAR RESPONDS WITH A POTENTIAL ROLE IN MEMORY DEFICITS. 2014 17 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 18 3935 39 LIVER-SPECIFIC KNOCKDOWN OF CLASS IIA HDACS HAS LIMITED EFFICACY ON GLUCOSE METABOLISM BUT ENTAILS SEVERE ORGAN SIDE EFFECTS IN MICE. HISTONE DEACETYLASES (HDACS) ARE IMPORTANT REGULATORS OF EPIGENETIC GENE MODIFICATION THAT ARE INVOLVED IN THE TRANSCRIPTIONAL CONTROL OF METABOLISM. IN PARTICULAR CLASS IIA HDACS HAVE BEEN SHOWN TO AFFECT HEPATIC GLUCONEOGENESIS AND PREVIOUS APPROACHES REVEALED THAT THEIR INHIBITION REDUCES BLOOD GLUCOSE IN TYPE 2 DIABETIC MICE. IN THE PRESENT STUDY, WE AIMED TO EVALUATE THE POTENTIAL OF CLASS IIA HDAC INHIBITION AS A THERAPEUTIC OPPORTUNITY FOR THE TREATMENT +OF METABOLIC DISEASES. FOR THAT, SIRNAS SELECTIVELY TARGETING HDAC4, 5 AND 7 WERE SELECTED AND USED TO ACHIEVE A COMBINATORIAL KNOCKDOWN OF THESE THREE CLASS IIA HDAC ISOFORMS. SUBSEQUENTLY, THE HEPATOCELLULAR EFFECTS AS WELL AS THE IMPACT ON GLUCOSE AND LIPID METABOLISM WERE ANALYZED IN VITRO AND IN VIVO. THE TRIPLE KNOCKDOWN RESULTED IN A STATISTICALLY SIGNIFICANT DECREASE OF GLUCONEOGENIC GENE EXPRESSION IN MURINE AND HUMAN HEPATOCYTE CELL MODELS. A SIMILAR HDAC-INDUCED DOWNREGULATION OF HEPATIC GLUCONEOGENESIS GENES COULD BE ACHIEVED IN MICE USING A LIVER-SPECIFIC LIPID NANOPARTICLE SIRNA FORMULATION. HOWEVER, THE EFFICACY ON WHOLE BODY GLUCOSE METABOLISM ASSESSED BY PYRUVATE-TOLERANCE TESTS WERE ONLY LIMITED AND DID NOT OUTWEIGH THE SAFETY FINDINGS OBSERVED BY HISTOPATHOLOGICAL ANALYSIS IN SPLEEN AND KIDNEY. MECHANISTICALLY, AFFYMETRIX GENE EXPRESSION STUDIES PROVIDE EVIDENCE THAT CLASS IIA HDACS DIRECTLY TARGET OTHER KEY FACTORS BEYOND THE DESCRIBED FORKHEAD BOX (FOXP) TRANSCRIPTION REGULATORS, SUCH AS HEPATOCYTE NUCLEAR FACTOR 4 ALPHA (HNF4A). DOWNSTREAM OF THESE FACTORS SEVERAL ADDITIONAL PATHWAYS WERE REGULATED NOT MERELY INCLUDING GLUCOSE AND LIPID METABOLISM AND TRANSPORT. IN CONCLUSION, THE LIVER-DIRECTED COMBINATORIAL KNOCKDOWN OF HDAC4, 5 AND 7 BY THERAPEUTIC SIRNAS AFFECTED MULTIPLE PATHWAYS IN VITRO, LEADING IN VIVO TO THE DOWNREGULATION OF GENES INVOLVED IN GLUCONEOGENESIS. HOWEVER, THE EFFECTS ON GENE EXPRESSION LEVEL WERE NOT PARALLELED BY A SIGNIFICANT REDUCTION OF GLUCONEOGENESIS IN MICE. COMBINED KNOCKDOWN OF HDAC ISOFORMS WAS ASSOCIATED WITH SEVERE ADVERSE EFFECTS IN VIVO, CHALLENGING THIS APPROACH AS A TREATMENT OPTION FOR CHRONIC METABOLIC DISORDERS LIKE TYPE 2 DIABETES. 2020 19 3292 31 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 20 315 31 ALCOHOL, DNA METHYLATION, AND CANCER. CANCER IS ONE OF THE MOST SIGNIFICANT DISEASES ASSOCIATED WITH CHRONIC ALCOHOL CONSUMPTION, AND CHRONIC DRINKING IS A STRONG RISK FACTOR FOR CANCER, PARTICULARLY OF THE UPPER AERODIGESTIVE TRACT, LIVER, COLORECTUM, AND BREAST. SEVERAL FACTORS CONTRIBUTE TO ALCOHOL-INDUCED CANCER DEVELOPMENT (I.E., CARCINOGENESIS), INCLUDING THE ACTIONS OF ACETALDEHYDE, THE FIRST AND PRIMARY METABOLITE OF ETHANOL, AND OXIDATIVE STRESS. HOWEVER, INCREASING EVIDENCE SUGGESTS THAT ABERRANT PATTERNS OF DNA METHYLATION, AN IMPORTANT EPIGENETIC MECHANISM OF TRANSCRIPTIONAL CONTROL, ALSO COULD BE PART OF THE PATHOGENETIC MECHANISMS THAT LEAD TO ALCOHOL-INDUCED CANCER DEVELOPMENT. THE EFFECTS OF ALCOHOL ON GLOBAL AND LOCAL DNA METHYLATION PATTERNS LIKELY ARE MEDIATED BY ITS ABILITY TO INTERFERE WITH THE AVAILABILITY OF THE PRINCIPAL BIOLOGICAL METHYL DONOR, S-ADENOSYLMETHIONINE (SAME), AS WELL AS PATHWAYS RELATED TO IT. SEVERAL MECHANISMS MAY MEDIATE THE EFFECTS OF ALCOHOL ON DNA METHYLATION, INCLUDING REDUCED FOLATE LEVELS AND INHIBITION OF KEY ENZYMES IN ONE-CARBON METABOLISM THAT ULTIMATELY LEAD TO LOWER SAME LEVELS, AS WELL AS INHIBITION OF ACTIVITY AND EXPRESSION OF ENZYMES INVOLVED IN DNA METHYLATION (I.E., DNA METHYLTRANSFERASES). FINALLY, VARIATIONS (I.E., POLYMORPHISMS) OF SEVERAL GENES INVOLVED IN ONE-CARBON METABOLISM ALSO MODULATE THE RISK OF ALCOHOL-ASSOCIATED CARCINOGENESIS. 2013