1 4404 154 MODULATION OF THE RESPONSE TO MYCOBACTERIUM LEPRAE AND PATHOGENESIS OF LEPROSY. THE INITIAL INFECTION BY THE OBLIGATE INTRACELLULAR BACILLUS MYCOBACTERIUM LEPRAE EVOLVES TO LEPROSY IN A SMALL SUBSET OF THE INFECTED INDIVIDUALS. TRANSMISSION IS BELIEVED TO OCCUR MAINLY BY EXPOSURE TO BACILLI PRESENT IN AEROSOLS EXPELLED BY INFECTED INDIVIDUALS WITH HIGH BACILLARY LOAD. MYCOBACTERIUM LEPRAE-SPECIFIC DNA HAS BEEN DETECTED IN THE BLOOD OF ASYMPTOMATIC HOUSEHOLD CONTACTS OF LEPROSY PATIENTS YEARS BEFORE ACTIVE DISEASE ONSET, SUGGESTING THAT, FOLLOWING INFECTION, THE BACTERIUM REACHES THE LYMPHATIC DRAINAGE AND THE BLOOD OF AT LEAST SOME INDIVIDUALS. THE LOWER TEMPERATURE AND AVAILABILITY OF PROTECTED MICROENVIRONMENTS MAY PROVIDE THE INITIAL CONDITIONS FOR THE SURVIVAL OF THE BACILLUS IN THE AIRWAYS AND SKIN. A SUBSET OF SKIN-RESIDENT MACROPHAGES AND THE SCHWANN CELLS OF PERIPHERAL NERVES, TWO M. LEPRAE PERMISSIVE CELLS, MAY PROTECT M. LEPRAE FROM EFFECTOR CELLS IN THE INITIAL PHASE OF THE INFECTION. THE INTERACTION OF M. LEPRAE WITH THESE CELLS INDUCES METABOLIC CHANGES, INCLUDING THE FORMATION OF LIPID DROPLETS, THAT ARE ASSOCIATED WITH MACROPHAGE M2 PHENOTYPE AND THE PRODUCTION OF MEDIATORS THAT FACILITATE THE DIFFERENTIATION OF SPECIFIC T CELLS FOR M. LEPRAE-EXPRESSED ANTIGENS TO A MEMORY REGULATORY PHENOTYPE. HERE, WE DISCUSS THE POSSIBLE INITIALS STEPS OF M. LEPRAE INFECTION THAT MAY LEAD TO ACTIVE DISEASE ONSET, MAINLY FOCUSING ON EVENTS PRIOR TO THE MANIFESTATION OF THE ESTABLISHED CLINICAL FORMS OF LEPROSY. WE HYPOTHESIZE THAT THE PROGRESSIVE DIFFERENTIATION OF T CELLS TO THE TREGS PHENOTYPE INHIBITS EFFECTOR FUNCTION AGAINST THE BACILLUS, ALLOWING AN INCREASE IN THE BACILLARY LOAD AND EVOLUTION OF THE INFECTION TO ACTIVE DISEASE. EPIGENETIC AND METABOLIC MECHANISMS DESCRIBED IN OTHER CHRONIC INFLAMMATORY DISEASES ARE EVALUATED FOR POTENTIAL APPLICATION TO THE UNDERSTANDING OF LEPROSY PATHOGENESIS. A POTENTIAL ROLE FOR POST-EXPOSURE PROPHYLAXIS OF LEPROSY IN REDUCING M. LEPRAE-INDUCED ANTI-INFLAMMATORY MEDIATORS AND, IN CONSEQUENCE, TREG/T EFFECTOR RATIOS IS PROPOSED. 2022 2 6456 22 THYMOSIN BETA4 PREVENTS OXIDATIVE STRESS, INFLAMMATION, AND FIBROSIS IN ETHANOL- AND LPS-INDUCED LIVER INJURY IN MICE. THYMOSIN BETA 4 (TBETA4), AN ACTIN-SEQUESTERING PROTEIN, IS INVOLVED IN TISSUE DEVELOPMENT AND REGENERATION. IT PREVENTS INFLAMMATION AND FIBROSIS IN SEVERAL TISSUES. WE INVESTIGATED THE ROLE OF TBETA4 IN CHRONIC ETHANOL- AND ACUTE LIPOPOLYSACCHARIDE- (LPS-) INDUCED MOUSE LIVER INJURY. C57BL/6 MICE WERE FED 5% ETHANOL IN LIQUID DIET FOR 4 WEEKS PLUS BINGE ETHANOL (5 G/KG, GAVAGE) WITH OR WITHOUT LPS (2 MG/KG, INTRAPERITONEAL) FOR 6 HOURS. TBETA4 (1 MG/KG, INTRAPERITONEAL) WAS ADMINISTERED FOR 1 WEEK. WE DEMONSTRATED THAT TBETA4 PREVENTED ETHANOL- AND LPS-MEDIATED INCREASE IN LIVER INJURY MARKERS AS WELL AS CHANGES IN LIVER PATHOLOGY. IT ALSO PREVENTED ETHANOL- AND LPS-MEDIATED INCREASE IN OXIDATIVE STRESS BY DECREASING ROS AND LIPID PEROXIDATION AND INCREASING THE ANTIOXIDANTS, REDUCED GLUTATHIONE AND MANGANESE-DEPENDENT SUPEROXIDE DISMUTASE. IT ALSO PREVENTED THE ACTIVATION OF NUCLEAR FACTOR KAPPA B BY BLOCKING THE PHOSPHORYLATION OF THE INHIBITORY PROTEIN, IKAPPAB, THEREBY PREVENTED PROINFLAMMATORY CYTOKINE PRODUCTION. MOREOVER, TBETA4 PREVENTED FIBROGENESIS BY SUPPRESSING THE EPIGENETIC REPRESSOR, METHYL-CPG-BINDING PROTEIN 2, THAT COORDINATELY REVERSED THE EXPRESSION OF PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR-GAMMA AND DOWNREGULATED FIBROGENIC GENES, PLATELET-DERIVED GROWTH FACTOR-BETA RECEPTOR, ALPHA-SMOOTH MUSCLE ACTIN, COLLAGEN 1, AND FIBRONECTIN, RESULTING IN REDUCED FIBROSIS. OUR DATA SUGGEST THAT TBETA4 HAS ANTIOXIDANT, ANTI-INFLAMMATORY, AND ANTIFIBROTIC POTENTIAL DURING ALCOHOLIC LIVER INJURY. 2018 3 3242 30 HEPATIC NCOR1 DELETION EXACERBATES ALCOHOL-INDUCED LIVER INJURY IN MICE BY PROMOTING CCL2-MEDIATED MONOCYTE-DERIVED MACROPHAGE INFILTRATION. NUCLEAR RECEPTOR COREPRESSOR 1 (NCOR1) IS A COREPRESSOR OF THE EPIGENETIC REGULATION OF GENE TRANSCRIPTION THAT HAS IMPORTANT FUNCTIONS IN METABOLISM AND INFLAMMATION, BUT LITTLE IS KNOWN ABOUT ITS ROLE IN ALCOHOL-ASSOCIATED LIVER DISEASE (ALD). IN THIS STUDY, WE DEVELOPED MICE WITH HEPATOCYTE-SPECIFIC NCOR1 KNOCKOUT (NCOR1(HEP-/-)) USING THE ALBUMIN-CRE/LOXP SYSTEM AND INVESTIGATED THE ROLE OF NCOR1 IN THE PATHOGENESIS OF ALD AND THE UNDERLYING MECHANISMS. THE TRADITIONAL ALCOHOL FEEDING MODEL AND NIAAA MODEL OF ALD WERE BOTH ESTABLISHED IN WILD-TYPE AND NCOR1(HEP-/-) MICE. WE SHOWED THAT AFTER ALD WAS ESTABLISHED, NCOR1(HEP-/-) MICE HAD WORSE LIVER INJURY BUT LESS STEATOSIS THAN WILD-TYPE MICE. WE DEMONSTRATED THAT HEPATOCYTE-SPECIFIC LOSS OF NCOR1 ATTENUATED LIVER STEATOSIS BY PROMOTING FATTY ACID OXIDATION BY UPREGULATING BMAL1 (A CIRCADIAN CLOCK COMPONENT THAT HAS BEEN REPORTED TO PROMOTE PEROXISOME PROLIFERATOR ACTIVATED RECEPTOR ALPHA (PPARALPHA)-MEDIATED FATTY BETA-OXIDATION BY UPREGULATING DE NOVO LIPID SYNTHESIS). ON THE OTHER HAND, HEPATOCYTE-SPECIFIC LOSS OF NCOR1 EXACERBATED ALCOHOL-INDUCED LIVER INFLAMMATION AND OXIDATIVE STRESS BY RECRUITING MONOCYTE-DERIVED MACROPHAGES VIA C-C MOTIF CHEMOKINE LIGAND 2 (CCL2). IN THE MOUSE HEPATOCYTE LINE AML12, NCOR1 KNOCKDOWN SIGNIFICANTLY INCREASED ETHANOL-INDUCED CCL2 RELEASE. THESE RESULTS SUGGEST THAT HEPATOCYTE NCOR1 PLAYS DISTINCT ROLES IN CONTROLLING LIVER INFLAMMATION AND STEATOSIS, WHICH PROVIDES NEW INSIGHTS INTO THE DEVELOPMENT OF TREATMENTS FOR STEATOHEPATITIS INDUCED BY CHRONIC ALCOHOL CONSUMPTION. 2022 4 6339 32 THE ROLE OF EPIGENETIC CHANGES IN THE PROGRESSION OF ALCOHOLIC STEATOHEPATITIS. ALCOHOLIC STEATOHEPATITIS (ASH) IS A PROGRESSION HEPATITIS WITH SEVERE FATTY LIVER AND ITS MORTALITY RATE FOR 30-DAYS IN PATIENTS ARE OVER 30%. ADDITIONALLY, ASH IS WELL KNOWN FOR ONE-FIFTH ALL ALCOHOLIC RELATED LIVER DISEASES IN THE WORLD. EXCESSIVE CHRONIC ALCOHOL CONSUMPTION IS ONE OF THE MOST COMMON CAUSES OF THE PROGRESSION OF ASH AND IS ASSOCIATED WITH POOR PROGNOSIS AND LIVER FAILURE. ALCOHOL ABUSE DYSREGULATES THE LIPID HOMEOSTASIS AND CAUSES OXIDATIVE STRESS AND INFLAMMATION IN THE LIVER. CONSEQUENTLY, METABOLIC PATHWAYS STIMULATING HEPATIC ACCUMULATION OF EXCESSIVE LIPID DROPLETS ARE INDUCED. RECENTLY, MANY STUDIES HAVE INDICATED A LINK BETWEEN ASH AND EPIGENETIC CHANGES, SHOWING DIFFERENTIAL EXPRESSION OF ALCOHOL-INDUCED EPIGENETIC GENES IN THE LIVER. HOWEVER, THE SPECIFIC MECHANISMS UNDERLYING THE PATHOGENESIS OF ASH REMAIN ELUSIVE. THUS, WE HERE SUMMARIZE THE CURRENT KNOWLEDGE ABOUT THE ROLES OF EPIGENETICS IN LIPOGENESIS, INFLAMMATION, AND APOPTOSIS IN THE CONTEXT OF ASH PATHOPHYSIOLOGY. ESPECIALLY, WE HIGHLIGHT THE LATEST FINDINGS ON THE ROLES OF SIRTUINS, A CONSERVED FAMILY OF CLASS-III HISTONE DEACETYLASES, IN ASH. ADDITIONALLY, WE DISCUSS THE INVOLVEMENT OF DNA METHYLATION, HISTONE MODIFICATIONS, AND MIRNAS IN ASH AS WELL AS THE ONGOING EFFORTS FOR THE CLINICAL TRANSLATION OF THE FINDINGS IN ASH-RELATED EPIGENETIC CHANGES. 2021 5 2326 23 EPIGENETIC REGULATION OF HOTAIR IN ADVANCED CHRONIC MYELOID LEUKEMIA. PURPOSE: CHRONIC MYELOID LEUKEMIA (CML) ACCOUNTS FOR ~10% OF LEUKEMIA CASES, AND ITS PROGRESSION INVOLVES EPIGENETIC GENE REGULATION. THIS STUDY INVESTIGATED EPIGENETIC REGULATION OF HOTAIR AND ITS TARGET MICRORNA, MIR-143, IN ADVANCED CML. PATIENTS AND METHODS: WE FIRST ISOLATED BONE MARROW MONONUCLEAR CELLS FROM 70 PATIENTS WITH DIFFERENT PHASES OF CML AND FROM HEALTHY DONORS AS NORMAL CONTROL; WE ALSO CULTURED K562 AND KCL22 CELLS, TREATED WITH DEMETHYLATION DRUG; MTT ASSAY, FLOW CYTOMETRY, QUANTITATIVE REAL-TIME POLYMERASE CHAIN REACTION (QPCR), METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION (MSP), WESTERN BLOT, LUCIFERASE ASSAY, RNA PULL-DOWN ASSAY AND RNA-BINDING PROTEIN IMMUNOPRECIPITATION (RIP) ASSAY WERE PERFORMED. RESULT: AS MEASURED BY QPCR, HOTAIR EXPRESSION IN K562 CELLS, KCL22 CELLS, AND SAMPLES FROM CASES OF ADVANCED-STAGE CML INCREASED WITH LEVELS OF SEVERAL DNA METHYLTRANSFERASES AND HISTONE DEACETYLATES, INCLUDING DNMT1, DNMT3A, HDAC1, EZH2, AND LSD1, AND MIR-143 LEVELS WERE DECREASED AND HOTAIR LEVELS WERE INCREASED. TREATMENT WITH 5-AZACYTIDINE, A DNA METHYLATION INHIBITOR, DECREASED DNMT1, DNMT3A, HDAC1, EZH2, LSD1 MRNA, PROTEIN LEVELS, AND HOTAIR MRNA LEVELS BUT INCREASED MIR-143 LEVELS. HOTAIR KNOCKDOWN AND MIR-143 OVEREXPRESSION BOTH INHIBITED PROLIFERATION AND PROMOTED APOPTOSIS IN KCL22 AND K562 CELLS THROUGH THE PI3K/AKT PATHWAY. RNA PULL-DOWN, MASS SPECTROMETRY, AND RIP ASSAYS SHOWED THAT HOTAIR INTERACTED WITH EZH2 AND LSD1. A DUAL-LUCIFERASE ASSAY DEMONSTRATED THAT HOTAIR INTERACTED WITH MIR-143. CONCLUSION: OUR FINDINGS DEMONSTRATE THE KEY EPIGENETIC INTERACTIONS OF HOTAIR RELATED TO CML PROGRESSION AND SUGGEST HOTAIR AS A POTENTIAL THERAPEUTIC TARGET FOR ADVANCED CML. FURTHERMORE, OUR RESULTS SUPPORT THE USE OF DEMETHYLATION DRUGS AS A CML TREATMENT STRATEGY. 2018 6 3164 31 GREEN TEA PREVENTS NAFLD BY MODULATION OF MIR-34A AND MIR-194 EXPRESSION IN A HIGH-FAT DIET MOUSE MODEL. BACKGROUND/AIMS: NONALCOHOLIC FATTY LIVER DISEASE (NAFLD) IS CONSIDERED THE HEPATIC MANIFESTATION OF METABOLIC SYNDROME. IT IS CURRENTLY THE MOST COMMON CHRONIC LIVER DISEASE WITH COMPLEX PATHOGENESIS AND CHALLENGING TREATMENT. HERE, WE INVESTIGATED THE HEPATOPROTECTIVE ROLE OF GREEN TEA (GT) AND DETERMINED THE INVOLVEMENT OF MIRNAS AND ITS MECHANISM OF ACTION. METHODS: MALE C57BL/6 MICE WERE FED WITH A HIGH-FAT DIET FOR 4 WEEKS. AFTER THIS PERIOD, THE ANIMALS RECEIVED GAVAGE WITH GT (500 MG/KG BODY WEIGHT) OVER 12 WEEKS (5 DAYS/WEEK). HEPG2 CELL LINES WERE TRANSFECTED WITH MIR-34A OR MIR-194 MIMETICS AND INHIBITORS TO VALIDATE THE IN VIVO RESULTS OR WERE TREATED WITH TNF-ALPHA TO EVALUATE MIRNA REGULATION. RESULTS: GT SUPPLEMENTATION PROTECTS AGAINST NAFLD DEVELOPMENT BY ALTERING LIPID METABOLISM, INCREASING GENE EXPRESSION INVOLVED IN TRIGLYCERIDES AND FATTY ACID CATABOLISM, AND DECREASING UPTAKE AND LIPID ACCUMULATION. THIS PHENOTYPE WAS ACCOMPANIED BY MIR-34A DOWNREGULATION AND AN INCREASE IN THEIR MRNA TARGETS SIRT1, PPARALPHA, AND INSIG2. GT UPREGULATED HEPATIC MIR-194 BY INHIBITING TNF-ALPHA ACTION LEADING TO A DECREASE IN MIR-194 TARGET GENES HMGCS/APOA5. CONCLUSION: OUR STUDY IDENTIFIED FOR THE FIRST TIME THAT THE BENEFICIAL EFFECTS OF GT IN THE LIVER CAN BE DUE TO THE MODULATION OF MIRNAS, OPENING NEW PERSPECTIVES FOR THE TREATMENT OF NAFLD FOCUSING ON EPIGENETIC REGULATION OF MIR-34A AND MIR-194 AS GREEN TEA TARGETS. 2019 7 5010 32 PEROXIDATION OF LINOLEIC, ARACHIDONIC AND OLEIC ACID IN RELATION TO THE INDUCTION OF OXIDATIVE DNA DAMAGE AND CYTOGENETIC EFFECTS. IN THE PRESENT STUDY, THE POSSIBLE ROLE OF THE POLYUNSATURATED FATTY ACIDS LINOLEIC AND ARACHIDONIC ACID IN THE CHEMICAL INDUCTION OF CARCINOGENESIS HAS BEEN INVESTIGATED. ANALYSIS OF 7,8-DIHYDRO-8-OXO-2'-DEOXYGUANOSINE (8-OXODG) LEVELS IN 2'-DEOXYGUANOSINE (DG) AND ISOLATED DNA HAS DEMONSTRATED THAT LINOLEIC AND ARACHIDONIC ACID ARE CAPABLE OF INDUCING THIS SPECIFIC GENOTOXIC DAMAGE. THIS EFFECT APPEARS TO BE RELATED TO THE DEGREE OF FATTY ACID UNSATURATION, SINCE IT WAS NOT INDUCED BY MONOUNSATURATED OLEIC ACID. ENZYMATIC PEROXIDATION OF LINOLEIC AND ARACHIDONIC ACID RESULTED IN A SIGNIFICANT INCREASE IN OXIDATIVE DNA DAMAGE. STUDIES ON THE INTERFERENCE OF RADICAL SCAVENGERS WITH THE INDUCTION OF 8-OXODG IN COMBINATION WITH ELECTRON SPIN RESONANCE SPECTROSCOPY DEMONSTRATED THAT THE SUPEROXIDE ANION WAS GENERATED DURING PEROXIDATION OF THESE FATTY ACIDS AND THAT SINGLET OXYGEN IS MOST LIKELY INVOLVED IN THE FORMATION OF OXIDATIVE DNA DAMAGE. THE LEVEL OF OXIDATIVE DAMAGE IN DG AND SINGLE-STRANDED DNA WAS HIGHER AS COMPARED TO THAT IN NATIVE DNA AFTER EQUIMOLAR TREATMENT. EXPOSURE OF HUMAN LYMPHOCYTES TO LINOLEIC OR ARACHIDONIC ACID DID NOT RESULT IN A SIGNIFICANT INCREASE IN LEVELS OF 8-OXODG. THIS MAY INDICATE THAT THE RATE OF INTRACELLULAR PEROXIDATION IS RELATIVELY LOW AND/OR THAT NUCLEAR DNA IN INTACT CELLS IS EFFECTIVELY PROTECTED AGAINST GENETIC DAMAGE INDUCED BY REACTIVE OXYGEN SPECIES. IT IS THEREFORE CONCLUDED THAT RELATIVELY SHORT PERIODS OF LINOLEIC OR ARACHIDONIC ACID ADMINISTRATION ARE NOT LIKELY TO IMPOSE A DIRECT GENOTOXIC RISK. IT CAN, HOWEVER, NOT BE EXCLUDED THAT CHRONIC EXPOSURE TO POLYUNSATURATED FATTY ACIDS INDUCES OXIDATIVE DNA DAMAGE OR IS RELATED TO CANCER RISK BY EPIGENETIC MECHANISMS, AS IS ALSO INDICATED BY THE OBSERVED CYTOTOXIC EFFECTS OF LINOLEIC AND ARACHIDONIC ACID. 1994 8 2862 30 FRUCTOSE-MEDIATED EFFECTS ON GENE EXPRESSION AND EPIGENETIC MECHANISMS ASSOCIATED WITH NAFLD PATHOGENESIS. NONALCOHOLIC FATTY LIVER DISEASE (NAFLD) IS A CHRONIC, FREQUENTLY PROGRESSIVE CONDITION THAT DEVELOPS IN RESPONSE TO EXCESSIVE HEPATOCYTE FAT ACCUMULATION (I.E., STEATOSIS) IN THE ABSENCE OF SIGNIFICANT ALCOHOL CONSUMPTION. LIVER STEATOSIS DEVELOPS AS A RESULT OF IMBALANCED LIPID METABOLISM, DRIVEN LARGELY BY INCREASED RATES OF DE NOVO LIPOGENESIS AND HEPATIC FATTY ACID UPTAKE AND REDUCED FATTY ACID OXIDATION AND/OR DISPOSAL TO THE CIRCULATION. FRUCTOSE IS A NATURALLY OCCURRING SIMPLE SUGAR, WHICH IS MOST COMMONLY CONSUMED IN MODERN DIETS IN THE FORM OF SUCROSE, A DISACCHARIDE COMPRISED OF ONE MOLECULE OF FRUCTOSE COVALENTLY BONDED WITH ONE MOLECULE OF GLUCOSE. A NUMBER OF OBSERVATIONAL AND EXPERIMENTAL STUDIES HAVE DEMONSTRATED DETRIMENTAL EFFECTS OF DIETARY FRUCTOSE CONSUMPTION NOT ONLY ON DIVERSE METABOLIC OUTCOMES SUCH AS INSULIN RESISTANCE AND OBESITY, BUT ALSO ON HEPATIC STEATOSIS AND NAFLD-RELATED FIBROSIS. DESPITE THE COMPELLING EVIDENCE THAT EXCESSIVE FRUCTOSE CONSUMPTION IS ASSOCIATED WITH THE PRESENCE OF NAFLD AND MAY EVEN PROMOTE THE DEVELOPMENT AND PROGRESSION OF NAFLD TO MORE CLINICALLY SEVERE PHENOTYPES, THE MOLECULAR MECHANISMS BY WHICH FRUCTOSE ELICITS EFFECTS ON DYSREGULATED LIVER METABOLISM REMAIN UNCLEAR. EMERGING DATA SUGGEST THAT DIETARY FRUCTOSE MAY DIRECTLY ALTER THE EXPRESSION OF GENES INVOLVED IN LIPID METABOLISM, INCLUDING THOSE THAT INCREASE HEPATIC FAT ACCUMULATION OR REDUCE HEPATIC FAT REMOVAL. THE AIM OF THIS REVIEW IS TO SUMMARIZE THE CURRENT RESEARCH SUPPORTING A ROLE FOR DIETARY FRUCTOSE INTAKE IN THE MODULATION OF TRANSCRIPTOMIC AND EPIGENETIC MECHANISMS UNDERLYING THE PATHOGENESIS OF NAFLD. 2020 9 5425 28 REGULATION OF MYELOPOIESIS BY THE TRANSCRIPTION FACTOR IRF8. INTERFERON REGULATORY FACTOR-8 (IRF8) IS A TRANSCRIPTION FACTOR EXPRESSED IN HEMATOPOIETIC CELLS, PARTICULARLY IN MONONUCLEAR PHAGOCYTES [MONOCYTES/MACROPHAGES AND DENDRITIC CELLS (DCS)] AND THEIR PROGENITORS. VARIOUS STUDIES HAVE DEMONSTRATED THAT IRF8 IS ESSENTIAL FOR THE DEVELOPMENT OF MONOCYTES, DCS, EOSINOPHILS, AND BASOPHILS. CONVERSELY, IRF8 SUPPRESSES THE GENERATION OF NEUTROPHILS. ACCORDINGLY, IRF8 (-/-) MICE DEVELOP IMMUNODEFICIENCY AND A CHRONIC MYELOID LEUKEMIA (CML)-LIKE DISEASE. MUTATIONS AND LOSS OF EXPRESSION OF THE HUMAN IRF8 GENE ARE ALSO ASSOCIATED WITH IMMUNODEFICIENCY AND CML, RESPECTIVELY. RECENT FINDINGS HAVE BEGUN TO REVEAL THE TRANSCRIPTION FACTOR NETWORK AND EPIGENETIC CHANGES GOVERNED BY IRF8. FOR EXAMPLE, IN MONONUCLEAR PHAGOCYTE PROGENITORS, IRF8 COOPERATES WITH PU.1 TO PROMOTE THE FORMATION OF PROMOTER-DISTAL ENHANCERS TO INDUCE MONOCYTE-RELATED GENES INCLUDING THE CRITICAL DOWNSTREAM TRANSCRIPTION FACTOR GENE KLF4. ON THE OTHER HAND, IRF8 BLOCKS C/EBPALPHA ACTIVITY TO SUPPRESS THE NEUTROPHIL DIFFERENTIATION PROGRAM. INDEED, IRF8 (-/-) MONONUCLEAR PHAGOCYTE PROGENITORS FAIL TO EFFICIENTLY GENERATE MONOCYTES AND DCS AND, INSTEAD, ABERRANTLY GIVE RISE TO NEUTROPHILS. THIS ARTICLE PROVIDES AN OVERVIEW OF RECENT ADVANCES IN OUR UNDERSTANDING OF THE ROLE OF IRF8 IN MYELOPOIESIS AND RELATED DISEASES. 2015 10 5150 29 PPARALPHA IN THE EPIGENETIC DRIVER SEAT OF NAFLD: NEW THERAPEUTIC OPPORTUNITIES FOR EPIGENETIC DRUGS? NONALCOHOLIC FATTY LIVER DISEASE (NAFLD) IS A GROWING EPIDEMIC AND THE MOST COMMON CAUSE OF CHRONIC LIVER DISEASE WORLDWIDE. IT CONSISTS OF A SPECTRUM OF LIVER DISORDERS RANGING FROM SIMPLE STEATOSIS TO NASH WHICH PREDISPOSES PATIENTS TO FURTHER FIBROSIS, CIRRHOSIS AND EVEN HEPATOCARCINOMA. DESPITE MUCH RESEARCH, AN APPROVED TREATMENT IS STILL LACKING. FINDING NEW THERAPEUTIC TARGETS HAS THEREFORE BEEN A MAIN PRIORITY. KNOWN AS A MAIN REGULATOR OF THE LIPID METABOLISM AND HIGHLY EXPRESSED IN THE LIVER, THE NUCLEAR RECEPTOR PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR-ALPHA (PPARALPHA) HAS BEEN IDENTIFIED AS AN ATTRACTIVE THERAPEUTIC TARGET. SINCE ITS EXPRESSION IS SILENCED BY DNA HYPERMETHYLATION IN NAFLD PATIENTS, MANY RESEARCH STRATEGIES HAVE AIMED TO RESTORE THE EXPRESSION OF PPARALPHA AND ITS TARGET GENES INVOLVED IN LIPID METABOLISM. ALTHOUGH PREVIOUSLY TESTED PPARALPHA AGONISTS DID NOT AMELIORATE THE DISEASE, CURRENT RESEARCH HAS SHOWN THAT PPARALPHA ALSO INTERACTS AND REGULATES EPIGENETIC DNMT1, JMJD3, TET AND SIRT1 ENZYMES. MOREOVER, THERE IS A GROWING BODY OF EVIDENCE SUGGESTING THE ORCHESTRATING ROLE OF EPIGENETICS IN THE DEVELOPMENT AND PROGRESSION OF NAFLD. THEREFORE, CURRENT THERAPEUTIC STRATEGIES ARE SHIFTING MORE TOWARDS EPIGENETIC DRUGS. THIS REVIEW PROVIDES A CONCISE OVERVIEW OF THE EPIGENETIC REGULATION OF NAFLD WITH A FOCUS ON PPARALPHA REGULATION AND HIGHLIGHTS RECENTLY IDENTIFIED EPIGENETIC INTERACTION PARTNERS OF PPARALPHA. 2022 11 3359 23 HISTONE H4 LYSINE 16 ACETYLATION CONTROLS CENTRAL CARBON METABOLISM AND DIET-INDUCED OBESITY IN MICE. NONCOMMUNICABLE DISEASES (NCDS) ACCOUNT FOR OVER 70% OF DEATHS WORLD-WIDE. PREVIOUS WORK HAS LINKED NCDS SUCH AS TYPE 2 DIABETES (T2D) TO DISRUPTION OF CHROMATIN REGULATORS. HOWEVER, THE EXACT MOLECULAR ORIGINS OF THESE CHRONIC CONDITIONS REMAIN ELUSIVE. HERE, WE IDENTIFY THE H4 LYSINE 16 ACETYLTRANSFERASE MOF AS A CRITICAL REGULATOR OF CENTRAL CARBON METABOLISM. HIGH-THROUGHPUT METABOLOMICS UNVEIL A SYSTEMIC AMINO ACID AND CARBOHYDRATE IMBALANCE IN MOF DEFICIENT MICE, MANIFESTING IN T2D PREDISPOSITION. ORAL GLUCOSE TOLERANCE TESTING (OGTT) REVEALS DEFECTS IN GLUCOSE ASSIMILATION AND INSULIN SECRETION IN THESE ANIMALS. FURTHERMORE, MOF DEFICIENT MICE ARE RESISTANT TO DIET-INDUCED FAT GAIN DUE TO DEFECTS IN GLUCOSE UPTAKE IN ADIPOSE TISSUE. MOF-MEDIATED H4K16AC DEPOSITION CONTROLS EXPRESSION OF THE MASTER REGULATOR OF GLUCOSE METABOLISM, PPARG AND THE ENTIRE DOWNSTREAM TRANSCRIPTIONAL NETWORK. GLUCOSE UPTAKE AND LIPID STORAGE CAN BE RECONSTITUTED IN MOF-DEPLETED ADIPOCYTES IN VITRO BY ECTOPIC GLUT4 EXPRESSION, PPARGAMMA AGONIST THIAZOLIDINEDIONE (TZD) TREATMENT OR SIRT1 INHIBITION. HENCE, CHRONIC IMBALANCE IN H4K16AC PROMOTES A DESTABILISATION OF METABOLISM TRIGGERING THE DEVELOPMENT OF A METABOLIC DISORDER, AND ITS MAINTENANCE PROVIDES AN UNPRECEDENTED REGULATORY EPIGENETIC MECHANISM CONTROLLING DIET-INDUCED OBESITY. 2021 12 956 34 CHRONIC MYELOMONOCYTIC LEUKAEMIA STEM CELL TRANSCRIPTOMES ANTICIPATE DISEASE MORPHOLOGY AND OUTCOME. BACKGROUND: CHRONIC MYELOMONOCYTIC LEUKAEMIA (CMML) IS A CLINICALLY HETEROGENEOUS STEM CELL MALIGNANCY WITH OVERLAPPING FEATURES OF MYELODYSPLASIA AND MYELOPROLIFERATION. OVER 90% OF PATIENTS CARRY MUTATIONS IN EPIGENETIC AND/OR SPLICING GENES, TYPICALLY DETECTABLE IN THE LIN(-)CD34(+)CD38(-) IMMUNOPHENOTYPIC STEM CELL COMPARTMENT IN WHICH THE LEUKAEMIA-INITIATING CELLS RESIDE. TRANSCRIPTIONAL DYSREGULATION AT THE STEM CELL LEVEL IS LIKELY FUNDAMENTAL TO DISEASE ONSET AND PROGRESSION. METHODS: WE PERFORMED SINGLE-CELL RNA SEQUENCING ON 6826 LIN(-)CD34(+)CD38(-)STEM CELLS FROM CMML PATIENTS AND HEALTHY CONTROLS USING THE DROPLET-BASED, ULTRA-HIGH-THROUGHPUT 10X PLATFORM. FINDINGS: WE FOUND SUBSTANTIAL INTER- AND INTRA-PATIENT HETEROGENEITY, WITH CMML STEM CELLS DISPLAYING DISTINCTIVE TRANSCRIPTIONAL PROGRAMS. COMPARED WITH NORMAL CONTROLS, CMML STEM CELLS EXHIBITED TRANSCRIPTOMES CHARACTERIZED BY INCREASED EXPRESSION OF MYELOID-LINEAGE AND CELL CYCLE GENES, AND LOWER EXPRESSION OF GENES SELECTIVELY EXPRESSED BY NORMAL HAEMATOPOIETIC STEM CELLS. NEUTROPHIL-PRIMED PROGENITOR GENES AND A MYC TRANSCRIPTION FACTOR REGULOME WERE PROMINENT IN STEM CELLS FROM CMML-1 PATIENTS, WHEREAS CMML-2 STEM CELLS EXHIBITED STRONG EXPRESSION OF INTERFERON-REGULATORY FACTOR REGULOMES, INCLUDING THOSE ASSOCIATED WITH IRF1, IRF7 AND IRF8. CMML-1 AND CMML-2 STEM CELLS (STAGES DISTINGUISHED BY PROPORTION OF DOWNSTREAM BLASTS AND PROMONOCYTES) DIFFERED SUBSTANTIALLY IN BOTH TRANSCRIPTOME AND PSEUDOTIME, INDICATING FUNDAMENTALLY DIFFERENT BIOLOGY UNDERPINNING THESE DISEASE STATES. GENE EXPRESSION AND PATHWAY ANALYSES HIGHLIGHTED POTENTIALLY TRACTABLE THERAPEUTIC VULNERABILITIES FOR DOWNSTREAM INVESTIGATION. IMPORTANTLY, CMML PATIENTS HARBOURED VARIABLY-SIZED SUBPOPULATIONS OF TRANSCRIPTIONALLY NORMAL STEM CELLS, INDICATING A POTENTIAL RESERVOIR TO RESTORE FUNCTIONAL HAEMATOPOIESIS. INTERPRETATION: OUR FINDINGS PROVIDE NOVEL INSIGHTS INTO THE CMML STEM CELL COMPARTMENT, REVEALING AN UNEXPECTED DEGREE OF HETEROGENEITY AND DEMONSTRATING THAT CMML STEM CELL TRANSCRIPTOMES ANTICIPATE DISEASE MORPHOLOGY, AND THEREFORE OUTCOME. FUNDING: PROJECT FUNDING WAS SUPPORTED BY OGLESBY CHARITABLE TRUST, CANCER RESEARCH UK, BLOOD CANCER UK, AND UK MEDICAL RESEARCH COUNCIL. 2020 13 319 30 ALCOHOLIC LIVER DISEASE. ALCOHOLIC LIVER DISEASE (ALD) IS THE MOST PREVALENT TYPE OF CHRONIC LIVER DISEASE WORLDWIDE. ALD CAN PROGRESS FROM ALCOHOLIC FATTY LIVER (AFL) TO ALCOHOLIC STEATOHEPATITIS (ASH), WHICH IS CHARACTERIZED BY HEPATIC INFLAMMATION. CHRONIC ASH CAN EVENTUALLY LEAD TO FIBROSIS AND CIRRHOSIS AND IN SOME CASES HEPATOCELLULAR CANCER (HCC). IN ADDITION, SEVERE ASH (WITH OR WITHOUT CIRRHOSIS) CAN LEAD TO ALCOHOLIC HEPATITIS, WHICH IS AN ACUTE CLINICAL PRESENTATION OF ALD THAT IS ASSOCIATED WITH LIVER FAILURE AND HIGH MORTALITY. MOST INDIVIDUALS CONSUMING >40 G OF ALCOHOL PER DAY DEVELOP AFL; HOWEVER, ONLY A SUBSET OF INDIVIDUALS WILL DEVELOP MORE ADVANCED DISEASE. GENETIC, EPIGENETIC AND NON-GENETIC FACTORS MIGHT EXPLAIN THE CONSIDERABLE INTERINDIVIDUAL VARIATION IN ALD PHENOTYPE. THE PATHOGENESIS OF ALD INCLUDES HEPATIC STEATOSIS, OXIDATIVE STRESS, ACETALDEHYDE-MEDIATED TOXICITY AND CYTOKINE AND CHEMOKINE-INDUCED INFLAMMATION. DIAGNOSIS OF ALD INVOLVES ASSESSING PATIENTS FOR ALCOHOL USE DISORDER AND SIGNS OF ADVANCED LIVER DISEASE. THE DEGREE OF AFL AND LIVER FIBROSIS CAN BE DETERMINED BY ULTRASONOGRAPHY, TRANSIENT ELASTOGRAPHY, MRI, MEASUREMENT OF SERUM BIOMARKERS AND LIVER BIOPSY HISTOLOGY. ALCOHOL ABSTINENCE ACHIEVED BY PSYCHOSOMATIC INTERVENTION IS THE BEST TREATMENT FOR ALL STAGES OF ALD. IN THE CASE OF ADVANCED DISEASE SUCH AS CIRRHOSIS OR HCC, LIVER TRANSPLANTATION MAY BE REQUIRED. THUS, NEW THERAPIES ARE URGENTLY NEEDED. 2018 14 5013 41 PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR-GAMMA AS A THERAPEUTIC TARGET FOR HEPATIC FIBROSIS: FROM BENCH TO BEDSIDE. HEPATIC FIBROSIS IS A DYNAMIC CHRONIC LIVER DISEASE OCCURRING AS A CONSEQUENCE OF WOUND-HEALING RESPONSES TO VARIOUS HEPATIC INJURIES. THIS DISORDER IS ONE OF PRIMARY PREDICTORS FOR LIVER-ASSOCIATED MORBIDITY AND MORTALITY WORLDWIDE. TO DATE, NO PHARMACOLOGICAL AGENT HAS BEEN APPROVED FOR HEPATIC FIBROSIS OR COULD BE RECOMMENDED FOR ROUTINE USE IN CLINICAL CONTEXT. CELLULAR AND MOLECULAR UNDERSTANDING OF HEPATIC FIBROSIS HAS REVEALED THAT PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR-GAMMA (PPARGAMMA), THE FUNCTIONING RECEPTOR FOR ANTIDIABETIC THIAZOLIDINEDIONES, PLAYS A PIVOTAL ROLE IN THE PATHOBIOLOGY OF HEPATIC STELLATE CELLS (HSCS), WHOSE ACTIVATION IS THE CENTRAL EVENT IN THE PATHOGENESIS OF HEPATIC FIBROSIS. ACTIVATION OF PPARGAMMA INHIBITS HSC COLLAGEN PRODUCTION AND MODULATES HSC ADIPOGENIC PHENOTYPE AT TRANSCRIPTIONAL AND EPIGENETIC LEVELS. THESE MOLECULAR INSIGHTS INDICATE PPARGAMMA AS A PROMISING DRUG TARGET FOR ANTIFIBROTIC CHEMOTHERAPY. INTENSIVE ANIMAL STUDIES HAVE DEMONSTRATED THAT STIMULATION OF PPARGAMMA REGULATORY SYSTEM THROUGH GENE THERAPY APPROACHES AND PPARGAMMA LIGANDS HAS THERAPEUTIC PROMISE FOR HEPATIC FIBROSIS INDUCED BY A VARIETY OF ETIOLOGIES. AT THE SAME TIME, THIAZOLIDINEDIONE AGENTS HAVE BEEN INVESTIGATED FOR THEIR CLINICAL BENEFITS PRIMARILY IN PATIENTS WITH NONALCOHOLIC STEATOHEPATITIS, A COMMON METABOLIC LIVER DISORDER WITH HIGH POTENTIAL TO PROGRESS TO FIBROSIS AND LIVER-RELATED DEATH. ALTHOUGH SOME STUDIES HAVE SHOWN INITIAL PROMISE, NONE HAS ESTABLISHED LONG-TERM EFFICACY IN WELL-CONTROLLED RANDOMIZED CLINICAL TRIALS. THIS COMPREHENSIVE REVIEW COVERS THE 10-YEAR DISCOVERIES OF THE MOLECULAR BASIS FOR PPARGAMMA REGULATION OF HSC PATHOPHYSIOLOGY AND THEN FOCUSES ON THE ANIMAL INVESTIGATIONS AND CLINICAL TRIALS OF VARIOUS THERAPEUTIC MODALITIES TARGETING PPARGAMMA FOR HEPATIC FIBROSIS. 2013 15 558 26 B-VITAMIN DEPENDENT METHIONINE METABOLISM AND ALCOHOLIC LIVER DISEASE. CONVINCING EVIDENCE LINKS ABERRANT B-VITAMIN DEPENDENT HEPATIC METHIONINE METABOLISM TO THE PATHOGENESIS OF ALCOHOLIC LIVER DISEASE (ALD). THIS REVIEW FOCUSES ON THE ESSENTIAL ROLES OF FOLATE AND VITAMINS B6 AND B12 IN HEPATIC METHIONINE METABOLISM, THE CAUSES OF THEIR DEFICIENCIES AMONG CHRONIC ALCOHOLIC PERSONS, AND HOW THEIR DEFICIENCIES TOGETHER WITH CHRONIC ALCOHOL EXPOSURE IMPACT ON ABERRANT METHIONINE METABOLISM IN THE PATHOGENESIS OF ALD. FOLATE IS THE DIETARY TRANSMETHYLATION DONOR FOR THE PRODUCTION OF S-ADENOSYLMETHIONINE (SAM), WHICH IS THE SUBSTRATE FOR ALL METHYLTRANSFERASES THAT REGULATE GENE EXPRESSIONS IN PATHWAYS OF LIVER INJURY, AS WELL AS A REGULATOR OF THE TRANSSULFURATION PATHWAY THAT IS ESSENTIAL FOR PRODUCTION OF GLUTATHIONE (GSH), THE PRINCIPAL ANTIOXIDANT FOR DEFENSE AGAINST OXIDATIVE LIVER INJURY. VITAMIN B12 REGULATES TRANSMETHYLATION REACTIONS FOR SAM PRODUCTION AND VITAMIN B6 REGULATES TRANSSULFURATION REACTIONS FOR GSH PRODUCTION. FOLATE DEFICIENCY ACCELERATES THE EXPERIMENTAL DEVELOPMENT OF ALD IN ETHANOL-FED ANIMALS WHILE REDUCING LIVER SAM LEVELS WITH RESULTANT ABNORMAL GENE EXPRESSION AND DECREASED PRODUCTION OF ANTIOXIDANT GSH. THROUGH ITS EFFECTS ON FOLATE METABOLISM, REDUCED SAM ALSO IMPAIRS NUCLEOTIDE BALANCE WITH RESULTANT INCREASED DNA STRAND BREAKS, OXIDATION, HEPATOCELLULAR APOPTOSIS, AND RISK OF CARCINOGENESIS. THE REVIEW ENCOMPASSES REFERENCED STUDIES ON MECHANISMS FOR PERTURBATIONS OF METHIONINE METABOLISM IN ALD, EVIDENCE FOR ALTERED GENE EXPRESSIONS AND THEIR EPIGENETIC REGULATION IN THE PATHOGENESIS OF ALD, AND CLINICAL STUDIES ON POTENTIAL PREVENTION AND TREATMENT OF ALD BY CORRECTION OF METHIONINE METABOLISM WITH SAM. 2013 16 312 26 ALCOHOL FEEDING IN MICE PROMOTES COLONIC HYPERPERMEABILITY AND CHANGES IN COLONIC ORGANOID STEM CELL FATE. BACKGROUND: ALCOHOL INCREASES INTESTINAL PERMEABILITY TO PROINFLAMMATORY MICROBIAL PRODUCTS THAT PROMOTE LIVER DISEASE, EVEN AFTER A PERIOD OF SOBRIETY. WE SOUGHT TO TEST THE HYPOTHESIS THAT ALCOHOL AFFECTS INTESTINAL STEM CELLS USING AN IN VIVO MODEL AND EX VIVO ORGANOIDS GENERATED FROM JEJUNUM AND COLON FROM MICE FED CHRONIC ALCOHOL. METHODS: MICE WERE FED A CONTROL OR AN ALCOHOL DIET. INTESTINAL PERMEABILITY, LIVER STEATOSIS-INFLAMMATION, AND STOOL SHORT-CHAIN FATTY ACIDS (SCFAS) WERE MEASURED. JEJUNUM AND COLONIC ORGANOIDS AND TISSUE WERE STAINED FOR STEM CELL, CELL LINEAGE, AND APICAL JUNCTION MARKERS WITH ASSESSMENT OF MRNA BY PCR AND RNA-SEQ. CHIP-PCR ANALYSIS WAS CARRIED OUT FOR NOTCH1 USING AN ANTIBODY SPECIFIC FOR ACETYLATED HISTONE 3. RESULTS: ALCOHOL-FED MICE EXHIBITED COLONIC (BUT NOT SMALL INTESTINAL) HYPERPERMEABILITY, STEATOHEPATITIS, AND DECREASED BUTYRATE/TOTAL SCFA RATIO IN STOOL. STEM CELL, CELL LINEAGE, AND APICAL JUNCTION MARKER STAINING IN TISSUE OR ORGANOIDS FROM JEJUNUM TISSUE WERE NOT IMPACTED BY ALCOHOL. ONLY CHROMOGRANIN A (CHGA) WAS INCREASED IN JEJUNUM ORGANOIDS BY QPCR. HOWEVER, COLONIC TISSUE AND ORGANOID STAINING EXHIBITED AN ALCOHOL-INDUCED SIGNIFICANT DECREASE IN CYTOKERATIN 20+ (KRT20+) ABSORPTIVE LINEAGE ENTEROCYTES, A DECREASE IN OCCLUDIN AND E-CADHERIN APICAL JUNCTION PROTEINS, AN INCREASE IN CHGA, AND AN INCREASE IN THE LGR5 STEM CELL MARKER. QPCR REVEALED AN ALCOHOL-INDUCED DECREASE IN COLONIC ORGANOID AND TISSUE NOTCH1, HES1, AND KRT20 AND INCREASED CHGA, SUPPORTING AN ALTERATION IN STEM CELL FATE DUE TO DECREASED NOTCH1 EXPRESSION. COLONIC TISSUE CHIP-PCR REVEALED ALCOHOL FEEDING SUPPRESSED NOTCH1 MRNA EXPRESSION (VIA DEACETYLATION OF HISTONE H3) AND DECREASED NOTCH1 TISSUE STAINING. CONCLUSIONS: DATA SUPPORT A MODEL FOR ALCOHOL-INDUCED COLONIC HYPERPERMEABILITY VIA EPIGENETIC EFFECTS ON NOTCH1, AND THUS HES1, SUPPRESSION THROUGH A MECHANISM INVOLVING HISTONE H3 DEACETYLATION AT THE NOTCH1 LOCUS. THIS DECREASED ENTEROCYTE AND INCREASED ENTEROENDOCRINE CELL COLONIC STEM CELL FATE AND DECREASED APICAL JUNCTIONAL PROTEINS LEADING TO HYPERPERMEABILITY. 2017 17 5915 32 TARGETING A PHOSPHO-STAT3-MIRNAS PATHWAY IMPROVES VESICULAR HEPATIC STEATOSIS IN AN IN VITRO AND IN VIVO MODEL. NON-ALCOHOLIC FATTY LIVER DISEASE (NAFLD) IS A LEADING CAUSE OF CHRONIC LIVER DISEASE. ALTHOUGH GENETIC PREDISPOSITION AND EPIGENETIC FACTORS CONTRIBUTE TO THE DEVELOPMENT OF NAFLD, OUR UNDERSTANDING OF THE MOLECULAR MECHANISM INVOLVED IN THE PATHOGENESIS OF THE DISEASE IS STILL EMERGING. HERE WE INVESTIGATED A POSSIBLE ROLE OF A MICRORNAS-STAT3 PATHWAY IN THE INDUCTION OF HEPATIC STEATOSIS. DIFFERENTIATED HEPARG CELLS TREATED WITH THE FATTY ACID SODIUM OLEATE (FATTY DHEPARG) RECAPITULATED FEATURES OF LIVER VESICULAR STEATOSIS AND ACTIVATED A CELL-AUTONOMOUS INFLAMMATORY RESPONSE, INDUCING STAT3-TYROSINE-PHOSPHORYLATION. WITH A GENOME-WIDE APPROACH (CHROMATIN IMMUNOPRECIPITATION SEQUENCING), MANY PHOSPHO-STAT3 BINDING SITES WERE IDENTIFIED IN FATTY DHEPARG CELLS AND SEVERAL STAT3 AND/OR NAFLD-REGULATED MICRORNAS SHOWED INCREASED EXPRESSION LEVELS, INCLUDING MIR-21. INNOVATIVE CARS (COHERENT ANTI-STOKES RAMAN SCATTERING) MICROSCOPY REVEALED THAT CHEMICAL INHIBITION OF STAT3 ACTIVITY DECREASED LIPID ACCUMULATION AND DEREGULATED STAT3-RESPONSIVE MICRORNAS, INCLUDING MIR-21, IN LIPID OVERLOADED DHEPARG CELLS. WE WERE ABLE TO SHOW IN VIVO THAT REDUCING PHOSPHO-STAT3-MIR-21 LEVELS IN C57/BL6 MICE LIVER, BY LONG-TERM TREATMENT WITH METFORMIN, PROTECTED MICE FROM AGING-DEPENDENT HEPATIC VESICULAR STEATOSIS. OUR RESULTS IDENTIFIED A MICRORNAS-PHOSPHOSTAT3 PATHWAY INVOLVED IN THE DEVELOPMENT OF HEPATIC STEATOSIS, WHICH MAY REPRESENT A MOLECULAR MARKER FOR BOTH DIAGNOSIS AND THERAPEUTIC TARGETING. 2018 18 3940 28 LNCRNA DLEU2 REGULATES SIRTUINS AND MITOCHONDRIAL RESPIRATORY CHAIN COMPLEX IV: A NOVEL PATHWAY IN OBESITY AND OFFSPRING'S HEALTH. BACKGROUND: LONG NON-CODING RNAS (LNCRNAS) HAVE EMERGED AS A RAPIDLY EXPANDING AREA OF INTEREST IN CHRONIC DISEASES. THEY ARE MOSTLY UNKNOWN FOR ROLES IN METABOLIC REGULATION. SIRTUINS, AN EPIGENETIC MODULATOR CLASS, REGULATE METABOLIC PATHWAYS. HOWEVER, HOW SIRTUINS ARE REGULATED VIA LNCRNA IS UNKNOWN. WE HYPOTHESIZED THAT A HIGH-FAT HIGH-FRUCTOSE DIET (HFD-HF) DURING PREGNANCY WOULD INCREASE THE RISK FOR OBESITY VIA LNCRNA-SIRTUIN PATHWAYS. METHODS: FEMALE C57BL/6 MICE (F0) WERE FED EITHER CHOW DIET (CD) OR HFD-HF FOR 6 WEEKS TILL BIRTH. THE PUPS (F1) WERE FED EITHER CD OR HFD-HF FOR 20 WEEKS. EXPRESSION OF DLEU2, SIRTUINS, MITOCHONDRIAL RESPIRATORY COMPLEXES, AND OXIDATIVE STRESS WERE INVESTIGATED IN THE F1 LIVERS. FASTING BLOOD GLUCOSE, INSULIN SENSITIVITY, GLUCOSE TOLERANCE, BODY AND TISSUES WEIGHT WERE MEASURED. A MECHANISTIC INTERACTION WAS THEN CARRIED OUT USING A DLEU2 KNOCKDOWN EXPERIMENT IN THE HEPG2 CELL. RESULTS: DLEU2 AND SIRTUINS WERE BOTH SIGNIFICANTLY DECREASED IN THE LIVERS OF HFD-HF FED MALE F1 WHOSE MOTHERS WERE EITHER FED CD OR HFD-HF DURING REPRODUCTIVE AND PREGNANCY WINDOWS. CONFIRMING THIS CONNECTION, UPON SILENCING DLEU2, TRANSCRIPTION LEVELS OF SIRT1 THROUGH 6 AND TRANSLATIONAL LEVELS OF SIRT1, 3, 5, AND 6 WERE SIGNIFICANTLY DOWNREGULATED. KNOCKDOWN OF DLEU2 SIGNIFICANTLY DECREASED THE PROTEIN LEVEL OF CYTOCHROME-C OXIDASE (COMPLEX IV, MTCO1) WITHOUT ALTERING OTHER MITOCHONDRIAL COMPLEXES, DECREASED MITOCHONDRIAL MEMBRANE POTENTIAL, DECREASED ATP, AND INCREASED REACTIVE OXYGEN SPECIES. INTERESTINGLY, IN F1 LIVERS, THE PROTEIN LEVEL OF MTCO1 WAS ALSO SIGNIFICANTLY DECREASED UNDER AN HFD-HF DIET OR EVEN UNDER CHOW DIET IF THE MOTHER WAS EXPOSED TO HFD-HF. CONCLUSION: OUR FINDINGS REVEAL FOR THE FIRST TIME THAT ONE LNCRNA CAN REGULATE SIRTUINS AND A SPECIFIC MITOCHONDRIAL COMPLEX. FURTHERMORE, DIET OR MATERNAL DIET CAN MODULATE DLEU2 AND ITS DOWNSTREAM REGULATORS IN OFFSPRING, SUGGESTING A POTENTIAL ROLE OF DLEU2 IN METABOLIC DISORDERS OVER ONE OR MORE GENERATIONS. 2022 19 1666 36 DOWNREGULATION OF MICRORNA-145A-5P PROMOTES STEATOSIS-TO-NASH PROGRESSION THROUGH UPREGULATION OF NR4A2. BACKGROUND & AIMS: THE MOLECULAR MECHANISMS UNDERLYING THE PROGRESSION OF SIMPLE STEATOSIS TO NON-ALCOHOLIC STEATOHEPATITIS (NASH) REMAIN INCOMPLETELY UNDERSTOOD, THOUGH THE POTENTIAL ROLE OF EPIGENETIC REGULATION BY MICRORNA (MIRNAS) IS AN AREA OF INCREASING INTEREST. IN THE PRESENT STUDY, WE AIMED TO INVESTIGATE THE ROLE AND MECHANISM OF MIRNAS DURING STEATOSIS-TO-NASH PROGRESSION. METHODS: MIR-145A-5P WAS IDENTIFIED AS AN IMPORTANT CHECKPOINT IN STEATOSIS-TO-NASH PROGRESSION. IN VIVO LOSS-OF-FUNCTION AND GAIN-OF-FUNCTION STUDIES WERE PERFORMED TO EXPLORE THE ROLE OF MIR-145A-5P AND NR4A2 IN NASH PROGRESSION. RNA-SEQUENCING AND BIOINFORMATIC ANALYSIS WERE USED TO INVESTIGATE THE TARGETS OF MIR-145A-5P. RESULTS: SUPPRESSION OF MIR-145A-5P IN THE LIVER AGGRAVATED LIPID ACCUMULATION AND ACTIVATED HEPATIC INFLAMMATION, LIVER INJURY AND FIBROSIS IN STEATOTIC MICE, WHEREAS ITS RESTORATION MARKEDLY ATTENUATED DIET-INDUCED NASH PATHOGENESIS. MECHANISTICALLY, MIR-145A-5P WAS ABLE TO DOWNREGULATE THE NUCLEAR RECEPTOR NR4A2 AND THUS INHIBIT THE EXPRESSION OF NASH-ASSOCIATED GENES. SIMILARLY, NR4A2 OVEREXPRESSION PROMOTED STEATOSIS-TO-NASH PROGRESSION WHILE LIVER-SPECIFIC NR4A2 KNOCKOUT MICE WERE PROTECTED FROM DIET-INDUCED NASH. THIS ROLE OF THE MIR-145A-5P/NR4A2 REGULATORY AXIS WAS ALSO CONFIRMED IN PRIMARY HUMAN HEPATOCYTES. FURTHERMORE, THE EXPRESSION OF MIR-145A-5P WAS REDUCED AND THE EXPRESSION OF NR4A2 WAS INCREASED IN THE LIVERS OF PATIENTS WITH NASH, WHILE THEIR EXPRESSION LEVELS SIGNIFICANTLY NEGATIVELY AND POSITIVELY CORRELATED WITH FEATURES OF LIVER PATHOLOGY, RESPECTIVELY. CONCLUSIONS: OUR FINDINGS HIGHLIGHT THE ROLE OF THE MIR-145A-5P/NR4A2 REGULATORY AXIS IN STEATOSIS-TO-NASH PROGRESSION, SUGGESTING THAT EITHER SUPPLEMENTATION OF MIR-145A-5P OR PHARMACOLOGICAL INHIBITION OF NR4A2 IN HEPATOCYTES MAY PROVIDE A PROMISING THERAPEUTIC APPROACH FOR THE TREATMENT OF NASH. IMPACT AND IMPLICATIONS: NON-ALCOHOLIC FATTY LIVER DISEASE (NAFLD) IS A DYNAMIC SPECTRUM OF CHRONIC LIVER DISEASES RANGING FROM SIMPLE STEATOSIS TO NON-ALCOHOLIC STEATOHEPATITIS (NASH). UNFORTUNATELY, THERE ARE CURRENTLY NO APPROVED DRUGS FOR NASH. OUR CURRENT STUDY IDENTIFIED MIR-145A-5P AS A NOVEL REGULATOR THAT INHIBITS STEATOSIS-TO-NASH PROGRESSION. WE FOUND THAT MIR-145A-5P WAS ABLE TO DOWNREGULATE THE NUCLEAR RECEPTOR NR4A2 TO SUPPRESS THE EXPRESSION OF NASH-ASSOCIATED GENES. THE DIFFERENTIAL EXPRESSION OF MIR-145A-5P AND NR4A2 WAS FURTHER CONFIRMED IN PATIENTS WITH NASH, RAISING THE POSSIBILITY THAT SUPPLEMENTATION OF MIR-145A-5P OR SUPPRESSION OF NR4A2 IN HEPATOCYTES MIGHT PROVIDE NOVEL STRATEGIES FOR TREATING NASH. 2023 20 3241 21 HEPATIC MICRORNA MODULATION MIGHT BE AN EARLY EVENT TO NON-ALCOHOLIC FATTY LIVER DISEASE DEVELOPMENT DRIVEN BY HIGH-FAT DIET IN MALE MICE. INTRODUCTION: METABOLIC ALTERATIONS CAUSED BY AN IMBALANCE OF MACRONUTRIENT CONSUMPTION ARE OFTEN RELATED TO THE MODULATION OF MICRORNAS (MIRNAS), WHICH COULD ALTER MRNAS EXPRESSION PROFILE AND ACCELERATE THE DEVELOPMENT OF NON-ALCOHOLIC FATTY LIVER DISEASE (NAFLD). AIMS: THIS STUDY AIMED TO INVESTIGATE THE CONTRIBUTION OF MIRNAS IN MODULATING EARLY STAGES OF NAFLD IN MICE SUBMITTED TO A HIGH-FAT DIET (HFD). METHODS AND RESULTS: MALE SWISS MICE, FED EITHER A CONTROL DIET OR AN HFD FOR 1, 3, 7, 15, 30, 56 DAYS, WERE ASSESSED FOR METABOLIC ALTERATIONS, GENE EXPRESSION AND NAFLD MARKERS. A HEPATOCYTE CELL LINE WAS USED TO INVESTIGATE THE EFFECTS OF MIR-370 MODULATION ON ENZYMES INVOLVED IN BETA-OXIDATION. BODY WEIGHT AND ADIPOSITY WERE HIGHER AFTER 7 DAYS OF HFD. FASTING GLUCOSE AND INSULIN INCREASED AFTER 3 AND 7 DAYS OF HFD, RESPECTIVELY. WHILE HEPATIC LIPID CONTENT INCREASED FROM THE FIRST DAY ON, HEPATIC GLYCOGEN HAD A DECREASE AFTER 3 DAYS OF HFD CONSUMPTION. MIR-370 AND LET-7 EXPRESSION INCREASED WITH ACUTE AND CHRONIC EXPOSURE TO HFD, ACCOMPANIED BY CARNITINE PALMITOYLTRANSFERASE 1A (CPT1A), ACYL-COA DEHYDROGENASE VERY LONG CHAIN (ACADVL) AND PROTEIN KINASE AMP-ACTIVATED CATALYTIC SUBUNIT 2 (PRKAA2) DOWNREGULATION, WHILE DECREASED MIR-122 EXPRESSION WAS ACCOMPANIED BY 1-ACYLGLYCEROL-3-PHOSPHATE-O-ACYLTRANSFERASE (AGPAT) UPREGULATION AFTER 56 DAYS OF HFD CONSUMPTION, SOME OF THEM CONFIRMED BY IN VITRO EXPERIMENTS. DESPITE FLUCTUATIONS IN TNFA AND IL6 MRNA LEVELS, MOLECULAR MODULATION WAS CONSISTENT WITH HEPATIC TG AND NAFLD DEVELOPMENT. CONCLUSION: HEPATIC MIR-370-122-LET7 MIRNA MODULATION COULD BE THE FIRST INSULT TO NAFLD DEVELOPMENT, PRECEDING CHANGES IN GLYCEMIC HOMEOSTASIS AND ADIPOSITY. 2022