1 3353 139 HISTONE DEMETHYLASES REGULATE ADIPOCYTE THERMOGENESIS. ADIPOCYTES PLAY A PIVOTAL ROLE IN THE REGULATION OF ENERGY METABOLISM. WHILE WHITE ADIPOCYTE STORES ENERGY, BROWN ADIPOCYTE DISSIPATES ENERGY BY PRODUCING HEAT. IN ADDITION, ANOTHER TYPE OF HEAT-PRODUCING ADIPOCYTE, BEIGE ADIPOCYTE, EMERGES IN WHITE ADIPOSE TISSUE IN RESPONSE TO CHRONIC COLDNESS. THIS PHENOTYPIC ADAPTATION TO THE COLD ENVIRONMENT IS CONSIDERED TO BE ATTRIBUTED TO THE EPIGENETIC MODIFICATIONS. HISTONE METHYLATION IS A CHEMICALLY STABLE EPIGENETIC MODIFICATION AND THUS A PROPER MECHANISM FOR LONG-LASTING CELLULAR MEMORY. SEVERAL HISTONE METHYL-MODIFYING ENZYMES SUCH AS EHMT1, JMJD1A, JMJD3, AND LSD1 ARE REPORTED TO BE INVOLVED IN THE BEIGE ADIPOSE CELL FATE DETERMINATION. AMONG THESE, A HISTONE DEMETHYLASE JMJD1A SENSES COLD ENVIRONMENT BY BEING PHOSPHORYLATED AT S265 IN RESPONSE TO BETA-ADRENERGIC RECEPTOR STIMULATION. PHOSPHORYLATED JMJD1A REGULATES BOTH ACUTE AND COLD THERMOGENESIS. UNDER ACUTE COLDNESS, PHOSPHORYLATED JMJD1A FORMS A COMPLEX WITH CHROMATIN REMODELER SWI/SNF AND DNA-BOUND PPARGAMMA, WHICH RECRUITS JMJD1A TO THE TARGET GENOMIC REGIONS IN BROWN ADIPOCYTE. THIS COMPLEX FORMATION, IN TURN, INDUCES THE EXPRESSION OF TARGET GENES BY BRINGING THE ENHANCER AND THE PROMOTER INTO CLOSE PROXIMITY. DURING CHRONIC COLDNESS, PHOSPHORYLATED JMJD1A REGULATES BEIGE ADIPOGENESIS THROUGH A TWO-STEP MECHANISM. IN THE FIRST STEP, PHOSPHORYLATED JMJD1A IS RECRUITED TO THE REGULATORY REGIONS OF TARGET GENES BY FORMING A COMPLEX WITH PRDM16, PGC1ALPHA, AND DNA-BOUND PPARGAMMA. IN THE SECOND STEP, JMJD1A DEMETHYLATES HISTONE H3K9ME2 AND INDUCES STABLE EXPRESSION OF BEIGE-SELECTIVE GENES. THE PHENOTYPIC ANALYSES OF JMJD1A-NULL MICE AND NON-PHOSPHORYLATED MUTANT S265A JMJD1A KNOCK-IN MICE INDICATE THAT JMJD1A IS A POTENTIAL THERAPEUTIC TARGET FOR THE TREATMENT OF OBESITY-RELATED DISEASES INCLUDING METABOLIC SYNDROME AND TYPE 2 DIABETES. 2018 2 35 26 A CHROMATIN ACTIVITY-BASED CHEMOPROTEOMIC APPROACH REVEALS A TRANSCRIPTIONAL REPRESSOME FOR GENE-SPECIFIC SILENCING. IMMUNE CELLS DEVELOP ENDOTOXIN TOLERANCE (ET) AFTER PROLONGED STIMULATION. ET INCREASES THE LEVEL OF A REPRESSION MARK H3K9ME2 IN THE TRANSCRIPTIONALLY SILENT CHROMATIN SPECIFICALLY ASSOCIATED WITH PRO-INFLAMMATORY GENES. HOWEVER, IT IS NOT CLEAR WHAT PROTEINS ARE FUNCTIONALLY INVOLVED IN THIS PROCESS. HERE WE SHOW THAT A NOVEL CHROMATIN ACTIVITY-BASED CHEMOPROTEOMIC (CHAC) APPROACH CAN DISSECT THE FUNCTIONAL CHROMATIN PROTEIN COMPLEXES THAT REGULATE ET-ASSOCIATED INFLAMMATION. USING UNC0638 THAT BINDS THE ENZYMATICALLY ACTIVE H3K9-SPECIFIC METHYLTRANSFERASE G9A/GLP, CHAC REVEALS THAT G9A IS CONSTITUTIVELY ACTIVE AT A G9A-DEPENDENT MEGA-DALTON REPRESSOME IN PRIMARY ENDOTOXIN-TOLERANT MACROPHAGES. G9A/GLP BROADLY IMPACTS THE ET-SPECIFIC REPROGRAMMING OF THE HISTONE CODE LANDSCAPE, CHROMATIN REMODELLING AND THE ACTIVITIES OF SELECT TRANSCRIPTION FACTORS. WE DISCOVER THAT THE G9A-DEPENDENT EPIGENETIC ENVIRONMENT PROMOTES THE TRANSCRIPTIONAL REPRESSION ACTIVITY OF C-MYC FOR GENE-SPECIFIC CO-REGULATION OF CHRONIC INFLAMMATION. CHAC MAY ALSO BE APPLICABLE TO DISSECT OTHER FUNCTIONAL PROTEIN COMPLEXES IN THE CONTEXT OF PHENOTYPIC CHROMATIN ARCHITECTURES. 2014 3 238 25 ADENOSINE KINASE: A KEY REGULATOR OF PURINERGIC PHYSIOLOGY. ADENOSINE (ADO) IS AN ESSENTIAL BIOMOLECULE FOR LIFE THAT PROVIDES CRITICAL REGULATION OF ENERGY UTILIZATION AND HOMEOSTASIS. ADENOSINE KINASE (ADK) IS AN EVOLUTIONARY ANCIENT RIBOKINASE DERIVED FROM BACTERIAL SUGAR KINASES THAT IS WIDELY EXPRESSED IN ALL FORMS OF LIFE, TISSUES AND ORGAN SYSTEMS THAT TIGHTLY REGULATES INTRACELLULAR AND EXTRACELLULAR ADO CONCENTRATIONS. THE FACILE ABILITY OF ADK TO ALTER ADO AVAILABILITY PROVIDES A "SITE AND EVENT" SPECIFICITY TO THE ENDOGENOUS PROTECTIVE EFFECTS OF ADO IN SITUATIONS OF CELLULAR STRESS. IN ADDITION TO MODULATING THE ABILITY OF ADO TO ACTIVATE ITS COGNATE RECEPTORS (P1 RECEPTORS), NUCLEAR ADK ISOFORM ACTIVITY HAS BEEN LINKED TO EPIGENETIC MECHANISMS BASED ON TRANSMETHYLATION PATHWAYS. PREVIOUS DRUG DISCOVERY RESEARCH HAS TARGETED ADK INHIBITION AS A THERAPEUTIC APPROACH TO MANAGE EPILEPSY, PAIN, AND INFLAMMATION. THESE EFFORTS GENERATED MULTIPLE CLASSES OF HIGHLY POTENT AND SELECTIVE INHIBITORS. HOWEVER, CLINICAL DEVELOPMENT OF EARLY ADK INHIBITORS WAS STOPPED DUE TO APPARENT MECHANISTIC TOXICITY AND THE LACK OF SUITABLE TRANSLATIONAL MARKERS. NEW INSIGHTS REGARDING THE POTENTIAL ROLE OF THE NUCLEAR ADK ISOFORM (ADK-LONG) IN THE EPIGENETIC MODULATION OF MALADAPTIVE DNA METHYLATION OFFERS THE POSSIBILITY OF IDENTIFYING NOVEL ADK-ISOFORM SELECTIVE INHIBITORS AND NEW INTERVENTIONAL STRATEGIES THAT ARE INDEPENDENT OF ADO RECEPTOR ACTIVATION. 2021 4 460 34 ARACHIDONIC ACID 15-LIPOXYGENASE: EFFECTS OF ITS EXPRESSION, METABOLITES, AND GENETIC AND EPIGENETIC VARIATIONS ON AIRWAY INFLAMMATION. ARACHIDONIC ACID 15-LIPOXYGENASE (ALOX15) IS AN ENZYME THAT CAN OXIDIZE POLYUNSATURATED FATTY ACIDS. ALOX15 IS STRONGLY EXPRESSED IN AIRWAY EPITHELIAL CELLS, WHERE IT CATALYZES THE CONVERSION OF ARACHIDONIC ACID TO 15-HYDROXYEICOSATETRAENOIC ACID (15-HETE) INVOLVED IN VARIOUS AIRWAY INFLAMMATORY DISEASES. INTERLEUKIN (IL)-4 AND IL-13 INDUCE ALOX15 EXPRESSION BY ACTIVATING JAK2 AND TYK2 KINASES AS WELL AS SIGNAL TRANSDUCERS AND ACTIVATORS OF TRANSCRIPTION (STATS) 1/3/5/6. ALOX15 UP-REGULATION AND SUBSEQUENT ASSOCIATION WITH PHOSPHATIDYLETHANOLAMINE-BINDING PROTEIN 1 (PEBP1) ACTIVATE THE MITOGEN-ACTIVATED EXTRACELLULAR SIGNAL-REGULATED KINASE (MEK)-EXTRACELLULAR SIGNAL-REGULATED KINASE (ERK) PATHWAY, THUS INDUCING EOSINOPHIL-MEDIATED AIRWAY INFLAMMATION. IN ADDITION, ALOX15 PLAYS A SIGNIFICANT ROLE IN PROMOTING THE MIGRATION OF IMMUNE CELLS, SUCH AS IMMATURE DENDRITIC CELLS, ACTIVATED T CELLS, AND MAST CELLS, AND AIRWAY REMODELING, INCLUDING GOBLET CELL DIFFERENTIATION. GENOME-WIDE ASSOCIATION STUDIES HAVE REVEALED MULTIPLE ALOX15 VARIANTS AND THEIR SIGNIFICANT CORRELATION WITH THE RISK OF DEVELOPING AIRWAY DISEASES. THE EPIGENETIC MODIFICATIONS OF THE ALOX15 GENE, SUCH AS DNA METHYLATION AND HISTONE MODIFICATIONS, HAVE BEEN SHOWN TO CLOSELY RELATE WITH AIRWAY INFLAMMATION. THIS REVIEW SUMMARIZES THE ROLE OF ALOX15 IN DIFFERENT PHENOTYPES OF ASTHMA, CHRONIC OBSTRUCTIVE PULMONARY DISEASE, CHRONIC RHINOSINUSITIS, ASPIRIN-EXACERBATED RESPIRATORY DISEASE, AND NASAL POLYPS, SUGGESTING NEW TREATMENT STRATEGIES FOR THESE AIRWAY INFLAMMATORY DISEASES WITH COMPLEX ETIOLOGY AND POOR TREATMENT RESPONSE. 2021 5 5332 33 PYRUVATE DEHYDROGENASE KINASE 1 AND 2 DEFICIENCY REDUCES HIGH-FAT DIET-INDUCED HYPERTROPHIC OBESITY AND INHIBITS THE DIFFERENTIATION OF PREADIPOCYTES INTO MATURE ADIPOCYTES. OBESITY IS NOW RECOGNIZED AS A DISEASE. THIS STUDY REVEALED A NOVEL ROLE FOR PYRUVATE DEHYDROGENASE KINASE (PDK) IN DIET-INDUCED HYPERTROPHIC OBESITY. MICE WITH GLOBAL OR ADIPOSE TISSUE-SPECIFIC PDK2 DEFICIENCY WERE PROTECTED AGAINST DIET-INDUCED OBESITY. THE WEIGHT OF ADIPOSE TISSUES AND THE SIZE OF ADIPOCYTES WERE REDUCED. ADIPOCYTE-SPECIFIC PDK2 DEFICIENCY SLIGHTLY INCREASED INSULIN SENSITIVITY IN HFD-FED MICE. IN STUDIES WITH 3T3-L1 PREADIPOCYTES, PDK2 AND PDK1 EXPRESSION WAS STRONGLY INCREASED DURING ADIPOGENESIS. EVIDENCE WAS FOUND FOR EPIGENETIC INDUCTION OF BOTH PDK1 AND PDK2. GAIN- AND LOSS-OF-FUNCTION STUDIES WITH 3T3-L1 CELLS REVEALED A CRITICAL ROLE FOR PDK1/2 IN ADIPOCYTE DIFFERENTIATION AND LIPID ACCUMULATION. PDK1/2 INDUCTION DURING DIFFERENTIATION WAS ALSO ACCOMPANIED BY INCREASED EXPRESSION OF HYPOXIA-INDUCIBLE FACTOR-1ALPHA (HIF1ALPHA) AND ENHANCED LACTATE PRODUCTION, BOTH OF WHICH WERE ABSENT IN THE CONTEXT OF PDK1/2 DEFICIENCY. EXOGENOUS LACTATE SUPPLEMENTATION INCREASED THE STABILITY OF HIF1ALPHA AND PROMOTED ADIPOGENESIS. PDK1/2 OVEREXPRESSION-MEDIATED ADIPOGENESIS WAS ABOLISHED BY HIF1ALPHA INHIBITION, SUGGESTING A ROLE FOR THE PDK-LACTATE-HIF1ALPHA AXIS DURING ADIPOGENESIS. IN HUMAN ADIPOSE TISSUE, THE EXPRESSION OF PDK1/2 WAS POSITIVELY CORRELATED WITH THAT OF THE ADIPOGENIC MARKER PPARGAMMA AND INVERSELY CORRELATED WITH OBESITY. SIMILARLY, PDK1/2 EXPRESSION IN MOUSE ADIPOSE TISSUE WAS DECREASED BY CHRONIC HIGH-FAT DIET FEEDING. WE CONCLUDE THAT PDK1 AND 2 ARE NOVEL REGULATORS OF ADIPOGENESIS THAT PLAY CRITICAL ROLES IN OBESITY. 2021 6 5601 30 RORALPHA IS CRUCIAL FOR ATTENUATED INFLAMMATORY RESPONSE TO MAINTAIN INTESTINAL HOMEOSTASIS. RETINOIC ACID-RELATED ORPHAN RECEPTOR ALPHA (RORALPHA) FUNCTIONS AS A TRANSCRIPTION FACTOR FOR VARIOUS BIOLOGICAL PROCESSES, INCLUDING CIRCADIAN RHYTHM, CANCER, AND METABOLISM. HERE, WE GENERATE INTESTINAL EPITHELIAL CELL (IEC)-SPECIFIC RORALPHA-DEFICIENT (RORALPHA(DELTAIEC)) MICE AND FIND THAT RORALPHA IS CRUCIAL FOR MAINTAINING INTESTINAL HOMEOSTASIS BY ATTENUATING NUCLEAR FACTOR KAPPAB (NF-KAPPAB) TRANSCRIPTIONAL ACTIVITY. RORALPHA(DELTAIEC) MICE EXHIBIT EXCESSIVE INTESTINAL INFLAMMATION AND HIGHLY ACTIVATED INFLAMMATORY RESPONSES IN THE DEXTRAN SULFATE SODIUM (DSS) MOUSE COLITIS MODEL. TRANSCRIPTOME ANALYSIS REVEALS THAT DELETION OF RORALPHA LEADS TO UP-REGULATION OF NF-KAPPAB TARGET GENES IN IECS. CHROMATIN IMMUNOPRECIPITATION ANALYSIS REVEALS CORECRUITMENT OF RORALPHA AND HISTONE DEACETYLASE 3 (HDAC3) ON NF-KAPPAB TARGET PROMOTERS AND SUBSEQUENT DISMISSAL OF CREB BINDING PROTEIN (CBP) AND BROMODOMAIN-CONTAINING PROTEIN 4 (BRD4) FOR TRANSCRIPTIONAL REPRESSION. TOGETHER, WE DEMONSTRATE THAT RORALPHA/HDAC3-MEDIATED ATTENUATION OF NF-KAPPAB SIGNALING CONTROLS THE BALANCE OF INFLAMMATORY RESPONSES, AND THERAPEUTIC STRATEGIES TARGETING THIS EPIGENETIC REGULATION COULD BE BENEFICIAL TO THE TREATMENT OF CHRONIC INFLAMMATORY DISEASES, INCLUDING INFLAMMATORY BOWEL DISEASE (IBD). 2019 7 2080 29 EPIGENETIC DNA METHYLATION OF EBI3 MODULATES HUMAN INTERLEUKIN-35 FORMATION VIA NFKB SIGNALING: A PROMISING THERAPEUTIC OPTION IN ULCERATIVE COLITIS. ULCERATIVE COLITIS (UC), A SEVERE CHRONIC DISEASE WITH UNCLEAR ETIOLOGY THAT IS ASSOCIATED WITH INCREASED RISK FOR COLORECTAL CANCER, IS ACCOMPANIED BY DYSREGULATION OF CYTOKINES. EPSTEIN-BARR VIRUS-INDUCED GENE 3 (EBI3) ENCODES A SUBUNIT IN THE UNIQUE HETERODIMERIC IL-12 CYTOKINE FAMILY OF EITHER PRO- OR ANTI-INFLAMMATORY FUNCTION. AFTER HAVING RECENTLY DEMONSTRATED THAT UPREGULATION OF EBI3 BY HISTONE ACETYLATION ALLEVIATES DISEASE SYMPTOMS IN A DEXTRAN SULFATE SODIUM (DSS)-TREATED MOUSE MODEL OF CHRONIC COLITIS, WE NOW AIMED TO EXAMINE A POSSIBLE FURTHER EPIGENETIC REGULATION OF EBI3 BY DNA METHYLATION UNDER INFLAMMATORY CONDITIONS. TREATMENT WITH THE DNA METHYLTRANSFERASE INHIBITOR (DNMTI) DECITABINE (DAC) AND TNFALPHA LED TO SYNERGISTIC UPREGULATION OF EBI3 IN HUMAN COLON EPITHELIAL CELLS (HCEC). USE OF DIFFERENT SIGNALING PATHWAY INHIBITORS INDICATED NFKAPPAB SIGNALING WAS NECESSARY AND PROPORTIONAL TO THE SYNERGISTIC EBI3 INDUCTION. MALDI-TOF/MS AND HPLC-ESI-MS/MS ANALYSIS OF DAC/TNFALPHA-TREATED HCEC IDENTIFIED IL-12P35 AS THE MOST PROBABLE BINDING PARTNER TO FORM A FUNCTIONAL PROTEIN. EBI3/IL-12P35 HETERODIMERS (IL-35) INDUCE THEIR OWN GENE UPREGULATION, SOMETHING THAT WAS INDEED OBSERVED IN HCEC CULTURED WITH MEDIA FROM PREVIOUSLY DAC/TNFALPHA-TREATED HCEC. THESE RESULTS SUGGEST THAT UNDER INFLAMMATORY AND DEMETHYLATING CONDITIONS THE UPREGULATION OF EBI3 RESULTS IN THE FORMATION OF ANTI-INFLAMMATORY IL-35, WHICH MIGHT BE CONSIDERED AS A THERAPEUTIC TARGET IN COLITIS. 2021 8 5511 23 RIBONUCLEASES IN TUMOR GROWTH. THIS REVIEW SUMMARIZES DATA ON AMBIGUOUS BIOLOGICAL FUNCTIONS OF RIBONUCLEASES (RNASES) AT TUMOR GROWTH. IN SOME CASES THE RAISED LEVEL OF ENZYME ACTIVITY IN BIOLOGICAL FLUIDS CAN BE REGARDED AS AN ADDITIONAL MARKER OF MALIGNANT GROWTH (PANCREAS CANCER, CHRONIC MYELOID LEUKEMIA, ETC.). AT THE SAME TIME THE ACTIVITY OF RNASES IS OFTEN LOWERED IN TUMOR TISSUE. HIGH SUBSTRATE SPECIFICITY OF PARTICULAR RNASES PROVIDES METABOLIC BALANCE BETWEEN VARIOUS KINDS OF RNAS WITH VARIOUS HALF-TIME EXCHANGE TURN. RNASES ARE THE IMPORTANT FACTORS OF EPIGENETIC REGULATION OF GENE ACTIVITY IN CELLS. THE ACTIVITY OF RNASES IS ADJUSTABLE BY INHIBITORS AND OTHER FACTORS, AND DEFINES TIME OF EXISTENCE OF DIFFERENT KINDS OF RNAS. RNASES (THE MODIFIED VARIANTS OF RNASE A, RNASES OF SEMEN FLUID OF THE CATTLE, RNASE OF AMPHIBIA OOCYTES) CAN BE USED AS ANTI-TUMOR THERAPEUTIC AGENTS. ON THE OTHER HAND, SOME INHIBITORS OF RNASES OF NATURAL OR SYNTHETIC ORIGIN WERE DEMONSTRATED TO BE PERSPECTIVE DRUGS THAT INHIBIT TUMOR GROWTH. 2009 9 768 24 CD47 (CLUSTER OF DIFFERENTIATION 47). CD47, ALSO KNOWN AS INTEGRIN-ASSOCIATED PROTEIN, IS A CONSTITUTIVELY AND UBIQUITOUSLY EXPRESSED TRANSMEMBRANE RECEPTOR. CD47 IS CONSERVED ACROSS AMNIOTES INCLUDING MAMMALS, REPTILES, AND BIRDS. EXPRESSION IS INCREASED IN MANY CANCERS AND, IN NON-MALIGNANT CELLS, BY STRESS AND WITH AGING. THE UP-REGULATION OF CD47 EXPRESSION IS GENERALLY EPIGENETIC, WHEREAS GENE AMPLIFICATION OCCURS WITH LOW FREQUENCY IN SOME CANCERS. CD47 IS A HIGH AFFINITY SIGNALING RECEPTOR FOR THE SECRETED PROTEIN THROMBOSPONDIN-1 (THBS1) AND THE COUNTER-RECEPTOR FOR SIGNAL REGULATORY PROTEIN-ALPHA (SIRPA, SIRPALPHA) AND SIRPGAMMA (SIRPG). CD47 INTERACTION WITH SIRPALPHA SERVES AS A MARKER OF SELF TO INNATE IMMUNE CELLS AND THEREBY PROTECTS CANCER CELLS FROM PHAGOCYTIC CLEARANCE. CONSEQUENTLY, HIGHER CD47 CORRELATES WITH A POOR PROGNOSIS IN SOME CANCERS, AND THERAPEUTIC BLOCKADE CAN SUPPRESS TUMOR GROWTH BY ENHANCING INNATE ANTITUMOR IMMUNITY. CD47 EXPRESSED ON CYTOTOXIC T CELLS, DENDRITIC CELLS, AND NK CELLS MEDIATES INHIBITORY THBS1 SIGNALING THAT FURTHER LIMITS ANTITUMOR IMMUNITY. CD47 LATERALLY ASSOCIATES WITH SEVERAL INTEGRINS AND THEREBY REGULATES CELL ADHESION AND MIGRATION. CD47 HAS ADDITIONAL LATERAL BINDING PARTNERS IN SPECIFIC CELL TYPES, AND LIGATION OF CD47 IN SOME CASES MODULATES THEIR FUNCTION. THBS1-CD47 SIGNALING IN NON-MALIGNANT CELLS INHIBITS NITRIC OXIDE/CGMP, CALCIUM, AND VEGF SIGNALING, MITOCHONDRIAL HOMEOSTASIS, STEM CELL MAINTENANCE, PROTECTIVE AUTOPHAGY, AND DNA DAMAGE RESPONSE, AND PROMOTES NADPH OXIDASE ACTIVITY. CD47 SIGNALING IS A PHYSIOLOGICAL REGULATOR OF PLATELET ACTIVATION, ANGIOGENESIS AND BLOOD FLOW. THBS1/CD47 SIGNALING IS FREQUENTLY DYSREGULATED IN CHRONIC DISEASES. 2021 10 3875 32 KDM2A DEFICIENCY IN MACROPHAGES ENHANCES THERMOGENESIS TO PROTECT MICE AGAINST HFD-INDUCED OBESITY BY ENHANCING H3K36ME2 AT THE PPARG LOCUS. KDM2A CATALYZES H3K36ME2 DEMETHYLATION TO PLAY AN INTRIGUING EPIGENETIC REGULATORY ROLE IN CELL PROLIFERATION, DIFFERENTIATION, AND APOPTOSIS. HEREIN WE FOUND THAT MYELOID-SPECIFIC KNOCKOUT OF KDM2A (LYSM-CRE-KDM2A(F/F), KDM2A(-/-)) PROMOTED MACROPHAGE M2 PROGRAM BY REPROGRAMING METABOLIC HOMEOSTASIS THROUGH ENHANCING FATTY ACID UPTAKE AND LIPOLYSIS. KDM2A(-/-) INCREASED H3K36ME2 LEVELS AT THE PPARG LOCUS ALONG WITH AUGMENTED CHROMATIN ACCESSIBILITY AND STAT6 RECRUITMENT, WHICH RENDERED MACROPHAGES WITH PREFERENTIAL M2 POLARIZATION. THEREFORE, THE KDM2A(-/-) MICE WERE HIGHLY PROTECTED FROM HIGH-FAT DIET (HFD)-INDUCED OBESITY, INSULIN RESISTANCE, AND HEPATIC STEATOSIS, AND FEATURED BY THE REDUCED ACCUMULATION OF ADIPOSE TISSUE MACROPHAGES AND REPRESSED CHRONIC INFLAMMATION FOLLOWING HFD CHALLENGE. PARTICULARLY, KDM2A(-/-) MACROPHAGES PROVIDED A MICROENVIRONMENT IN FAVOR OF THERMOGENESIS. UPON HFD OR COLD CHALLENGE, THE KDM2A(-/-) MICE MANIFESTED HIGHER CAPACITY FOR INDUCING ADIPOSE BROWNING AND BEIGING TO PROMOTE ENERGY EXPENDITURE. COLLECTIVELY, OUR FINDINGS DEMONSTRATE THE IMPORTANCE OF KDM2A-MEDIATED H3K36 DEMETHYLATION IN ORCHESTRATING MACROPHAGE POLARIZATION, PROVIDING NOVEL INSIGHT THAT TARGETING KDM2A IN MACROPHAGES COULD BE A VIABLE THERAPEUTIC APPROACH AGAINST OBESITY AND INSULIN RESISTANCE. 2021 11 1282 32 DECIPHERING THE ACTIVE CONSTITUENTS OF DABUSHEN DECOCTION OF AMELIORATING OSTEOARTHRITIS VIA PPARGAMMA PRESERVATION BY TARGETING DNMT1. OSTEOARTHRITIS (OA) IS A MULTIFACTORIAL AND CHRONIC DEGENERATIVE JOINT DISEASE. DUE TO THE ADVERSE EFFECTS OF CURRENTLY USED DRUGS, A SAFER AND MORE EFFECTIVE THERAPY FOR TREATING OA IS NEEDED. PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR-GAMMA (PPARGAMMA) IS A KEY PROTEIN PROTECTING CARTILAGE. DNMT1-MEDIATED HYPERMETHYLATION OF PPARGAMMA PROMOTER LEADS TO ITS SUPPRESSION. THEREFORE, DNMT1 MIGHT BE AN EFFECTIVE TARGET FOR EXERTING CARTILAGE PROTECTIVE EFFECTS BY REGULATING THE EPIGENETIC EXPRESSION OF PPARGAMMA. DABUSHEN DECOCTION (DD) IS A REPRESENTATIVE PRESCRIPTION OF DUNHUANG ANCIENT MEDICAL PRESCRIPTION, WHICH HAS A POTENTIAL THERAPEUTIC EFFECT ON OA. SO FAR, THE RESEARCH OF THE EFFICACY AND MATERIAL BASIS OF DD IN THE TREATMENT OF OA REMAINS UNCLEAR. IN THIS STUDY, MICRO-CT, HE STAINING, S-O STAINING, AND IMMUNOHISTOCHEMISTRY ANALYSIS WERE USED TO DEMONSTRATE THAT DD INCREASED THE EXPRESSION OF PPARGAMMA AND COLLAGEN SYNTHESIS IN AN OA RAT MODEL. NEXT, THE STRUCTURE OF DNMT1 WAS USED TO SCREEN THE ACTIVE CONSTITUENTS OF DD BY MOLECULAR DOCKING METHOD FOR TREATMENT OA. SEVEN POTENTIAL ACTIVE CONSTITUENTS, INCLUDING ISOLIQUIRITIGENIN, EMODIN, TAXIFOLIN, CATALPOL, ALISOL A, ZINGERONE, AND SCHISANDRIN C WERE HITED. THE PROTECTIVE EFFECT OF THE POTENTIAL ACTIVE CONSTITUENTS TO CHONDROCYTES WERE EVALUATED BY PROTEIN CAPILLARY ELECTROPHORESIS, IMMUNOFLUORESCENCE ASSAYS, AND EX VIVO CULTURE OF RAT KNEE CARTILAGE. THE FIVE CONSTITUENTS, SUCH AS ALISOL A, EMODIN, TAXIFOLIN, ISOLIQUIRITIGENIN, AND SCHISANDRIN C COULD PROMOTE THE EXPRESSION OF PPARGAMMA AND AMELIORATE IL-1BETA-INDUCED DOWNREGULATION OF COLLAGEN II AND THE PRODUCTION OF MMP-13. ALISOL A AND EMODIN COULD EFFECTIVELY MITIGATE CARTILAGE DAMAGE. AT LAST, MOLECULAR DYNAMICS SIMULATIONS WITH MM-GBSA METHOD WAS APPLIED TO INVESTIGATE THE INTERACTION PATTERN OF THE ACTIVE CONSTITUENTS AND DNMT1 COMPLEXES. THE FIVE CONSTITUENTS, SUCH AS ALISOL A, EMODIN, TAXIFOLIN, ISOLIQUIRITIGENIN, AND SCHISANDRIN C ACHIEVED A STABLE BINDING PATTERN WITH DNMT1, IN WHICH ALISOL A HAS A RELATIVELY HIGH BINDING FREE ENERGY. IN CONCLUSION, THIS STUDY ELUCIDATES THAT THE ACTIVE CONSTITUENTS OF DD (ALISOL A, EMODIN, TAXIFOLIN, ISOLIQUIRITIGENIN, AND SCHISANDRIN C) COULD AMELIORATE OSTEOARTHRITIS VIA PPARGAMMA PRESERVATION BY TARGETING DNMT1.THESE FINDINGS FACILITATED CLINICAL USE OF DD AND PROVIDED A VALUABLE STRATEGY FOR DEVELOPING NATURAL EPIGENETIC MODULATORS FROM CHINESE HERBAL FORMULA. 2022 12 3161 34 GRAINYHEAD-LIKE 2 (GRHL2) INHIBITS KERATINOCYTE DIFFERENTIATION THROUGH EPIGENETIC MECHANISM. WE RECENTLY IDENTIFIED GRAINYHEAD-LIKE 2 (GRHL2), A MAMMALIAN HOMOLOG OF GRAINYHEAD IN DROSOPHILA, TO BE A NOVEL TRANSCRIPTION FACTOR THAT REGULATES HTERT GENE EXPRESSION AND ENHANCES PROLIFERATION OF NORMAL HUMAN EPIDERMAL KERATINOCYTES (NHEK). IN THE CURRENT STUDY, WE SHOW THAT GRHL2 IMPAIRS KERATINOCYTE DIFFERENTIATION THROUGH TRANSCRIPTIONAL INHIBITION OF THE GENES CLUSTERED AT THE EPIDERMAL DIFFERENTIATION COMPLEX (EDC), LOCATED AT CHROMOSOME 1Q21. GENE EXPRESSION PROFILING AND SUBSEQUENT IN VITRO ASSAYS REVEALED CONSISTENT DOWNREGULATION OF EDC GENES, FOR EXAMPLE, IVL, KRT1, FLG, LCES, AND SPRRS, IN NHEK EXPRESSING EXOGENOUS GRHL2. IN VIVO BINDING ASSAY BY CHROMATIN IMMUNOPRECIPITATION REVEALED GRHL2 ASSOCIATION AT THE PROMOTER REGIONS OF ITS TARGET GENES, MANY OF WHICH BELONG TO EDC. EXOGENOUS GRHL2 EXPRESSION ALSO INHIBITED RECRUITMENT OF HISTONE DEMETHYLASE JMJD3 TO THE EDC GENE PROMOTERS AND ENHANCED THE LEVEL OF HISTONE 3 LYS 27 TRIMETHYLATION ENRICHMENT AT THESE PROMOTERS. SURVEY OF GRHL2 EXPRESSION IN HUMAN SKIN TISSUES DEMONSTRATED ENHANCED PROTEIN AND MRNA LEVELS IN CHRONIC SKIN LESIONS WITH IMPAIRED KERATINOCYTE DIFFERENTIATION, FOR EXAMPLE, ATOPIC DERMATITIS AND PSORIASIS, COMPARED WITH NORMAL EPIDERMIS. THESE DATA INDICATE THAT GRHL2 IMPAIRS EPIDERMAL DIFFERENTIATION BY INHIBITING EDC GENE EXPRESSION THROUGH EPIGENETIC MECHANISMS AND SUPPORT ITS ROLE IN THE HYPERPROLIFERATIVE SKIN DISEASES. 2012 13 2818 16 FIBROSIS UNDER ARREST. APPROXIMATELY 5% OF PEOPLE THAT ARE HOSPITALIZED FOR ANY REASON DEVELOP ACUTE KIDNEY FAILURE, WHICH, IN SOME CASES, PROGRESSES TO A CHRONIC CONDITION RESULTING IN FIBROSIS OF THE KIDNEY AND PERMANENT CHANGES IN THE ORGAN'S FUNCTION. TWO NEW STUDIES SUGGEST THAT CELL CYCLE ARREST OF EPITHELIAL CELLS AND EPIGENETIC MODIFICATIONS HAVE KEY ROLES IN THE SWITCH TO CHRONIC DISEASE (PAGES 535-543 AND 544-550). 2010 14 2758 26 EXPRESSION OF HORMONAL CARCINOGENESIS GENES AND RELATED REGULATORY MICRORNAS IN UTERUS AND OVARIES OF DDT-TREATED FEMALE RATS. THE INSECTICIDE DICHLORODIPHENYLTRICHLOROETHANE (DDT) IS A NONMUTAGENIC XENOBIOTIC COMPOUND ABLE TO EXERT ESTROGEN-LIKE EFFECTS RESULTING IN ACTIVATION OF ESTROGEN RECEPTOR-ALPHA (ERALPHA) FOLLOWED BY CHANGED EXPRESSION OF ITS DOWNSTREAM TARGET GENES. IN ADDITION, STUDIES PERFORMED OVER RECENT YEARS SUGGEST THAT DDT MAY ALSO INFLUENCE EXPRESSION OF MICRORNAS. HOWEVER, AN IMPACT OF DDT ON EXPRESSION OF ER, MICRORNAS, AND RELATED TARGET GENES HAS NOT BEEN FULLY ELUCIDATED. HERE, USING REAL-TIME PCR, WE ASSESSED CHANGES IN EXPRESSION OF KEY GENES INVOLVED IN HORMONAL CARCINOGENESIS AS WELL AS POTENTIALLY RELATED REGULATORY ONCOGENIC/TUMOR SUPPRESSOR MICRORNAS AND THEIR TARGET GENES IN THE UTERUS AND OVARIES OF FEMALE WISTAR RATS DURING SINGLE AND CHRONIC MULTIPLE-DOSE DDT EXPOSURE. WE FOUND THAT APPLYING DDT RESULTS IN ALTERED EXPRESSION OF MICRORNAS-221, -222, -205, -126A, AND -429, THEIR TARGET GENES (PTEN, DICER1), AS WELL AS GENES INVOLVED IN HORMONAL CARCINOGENESIS (ESR1, PGR, CCND1, CYP19A1). NOTABLY, CYP19A1 EXPRESSION SEEMS TO BE ALSO REGULATED BY MICRORNAS-221, -222, AND -205. THE DATA SUGGEST THAT EPIGENETIC EFFECTS INDUCED BY DDT AS A POTENTIAL CARCINOGEN MAY BE BASED ON AT LEAST TWO MECHANISMS: (I) ACTIVATION OF ERALPHA FOLLOWED BY ALTERED EXPRESSION OF THE TARGET GENES ENCODING RECEPTOR PGR AND CCND1 AS WELL AS IMPAIRED EXPRESSION OF CYP19A1, AFFECTING, THEREBY, CELL HORMONE BALANCE; AND (II) CHANGED EXPRESSION OF MICRORNAS RESULTING IN IMPAIRED EXPRESSION OF RELATED TARGET GENES INCLUDING REDUCED LEVEL OF CYP19A1 MRNA. 2017 15 3130 33 GLAST BUT NOT LEAST--DISTRIBUTION, FUNCTION, GENETICS AND EPIGENETICS OF L-GLUTAMATE TRANSPORT IN BRAIN--FOCUS ON GLAST/EAAT1. SYNAPTICALLY RELEASED L-GLUTAMATE, THE MOST IMPORTANT EXCITATORY NEUROTRANSMITTER IN THE CNS, IS REMOVED FROM EXTRACELLULAR SPACE BY FAST AND EFFICIENT TRANSPORT MEDIATED BY SEVERAL TRANSPORTERS; THE MOST ABUNDANT ONES ARE EAAT1/GLAST AND EAAT2/GLT1. THE REVIEW FIRST SUMMARIZES THEIR LOCATION, FUNCTIONS AND BASIC CHARACTERISTICS. WE THEN LOOK AT GENETICS AND EPIGENETICS OF EAAT1/GLAST AND EAAT2/GLT1 AND PERFORM IN SILICO ANALYSES OF THEIR PROMOTER REGIONS. THERE IS ONE CPG ISLAND IN SLC1A2 (EAAT2/GLT1) GENE AND NONE IN SLC1A3 (EAAT1/GLAST) SUGGESTING THAT DNA METHYLATION IS NOT THE MOST IMPORTANT EPIGENETIC MECHANISM REGULATING EAAT1/GLAST LEVELS IN BRAIN. THERE ARE TARGETS FOR SPECIFIC MIRNA IN SLC1A2 (EAAT2/GLT1) GENE. WE ALSO NOTE THAT WHILE DEFECTS IN EAAT2/GLT1 HAVE BEEN ASSOCIATED WITH VARIOUS PATHOLOGICAL STATES INCLUDING CHRONIC NEURODEGENERATIVE DISEASES, VERY LITTLE IS KNOWN ON POSSIBLE CONTRIBUTIONS OF DEFECTIVE OR DYSFUNCTIONAL EAAT1/GLAST TO ANY SPECIFIC BRAIN DISEASE. FINALLY, WE REVIEW EVIDENCE OF EAAT1/GLAST INVOLVEMENT IN MECHANISMS OF BRAIN RESPONSE TO ALCOHOLISM AND PRESENT SOME PRELIMINARY DATA SHOWING THAT ETHANOL, AT CONCENTRATIONS WHICH MAY BE REACHED FOLLOWING HEAVY DRINKING, CAN HAVE AN EFFECT ON THE DISTRIBUTION OF EAAT1/GLAST IN CULTURED ASTROCYTES; THE EFFECT IS BLOCKED BY BACLOFEN, A GABA-B RECEPTOR AGONIST AND A DRUG POTENTIALLY USEFUL IN THE TREATMENT OF ALCOHOLISM. WE ARGUE THAT MORE RESEARCH EFFORT SHOULD BE FOCUSED ON EAAT1/GLAST, PARTICULARLY IN RELATION TO ALCOHOLISM AND DRUG ADDICTION. 2015 16 5863 30 SUPPRESSION OF ALLERGIC ASTHMA BY LOSS OF FUNCTION OF MIZ1-MEDIATED TH1 SKEWING. ASTHMA IS THE MOST PREVALENT CHRONIC RESPIRATORY DISEASE WORLDWIDE. THERE IS CURRENTLY NO CURE, AND IT REMAINS AN IMPORTANT CAUSE OF MORBIDITY AND MORTALITY. HERE WE REPORT THAT LUNG-SPECIFIC LOSS OF FUNCTION OF THE TRANSCRIPTION FACTOR MIZ1 (C-MYC-INTERACTING ZINC FINGER PROTEIN-1) UPREGULATES THE PRO-T-HELPER CELL TYPE 1 CYTOKINE IL-12. UPREGULATION OF IL-12 IN TURN STIMULATES A TH1 RESPONSE, THEREBY COUNTERACTING T-HELPER CELL TYPE 2 RESPONSE AND PREVENTING THE ALLERGIC RESPONSE IN MOUSE MODELS OF HOUSE DUST MITE- AND OVA (OVALBUMIN)-INDUCED ASTHMA. USING TRANSGENIC MICE EXPRESSING CRE UNDER A CELL-SPECIFIC PROMOTER, WE DEMONSTRATE THAT MIZ1 ACTS IN LUNG EPITHELIAL CELLS AND DENDRITIC CELLS IN ASTHMA. CHROMATIN IMMUNOPRECIPITATION COUPLED WITH HIGH-THROUGHPUT DNA SEQUENCING OR QUANTITATIVE PCR REVEALS THE BINDING OF MIZ1 ON THE IL12 PROMOTER INDICATING DIRECT REPRESSION OF IL-12 BY MIZ1. IN ADDITION, HDAC1 (HISTONE DEACETYLASE 1) IS RECRUITED TO THE IL12 PROMOTER IN A MIZ1-DEPDENENT MANNER, SUGGESTING EPIGENETIC REPRESSION OF IL12 BY MIZ1. FURTHERMORE, MIZ1 IS UPREGULATED IN THE LUNGS OF ASTHMATIC MICE. OUR DATA TOGETHER SUGGEST THAT MIZ1 IS UPREGULATED DURING ASTHMA, WHICH IN TURN PROMOTES ASTHMA PATHOGENESIS BY PREVENTING TH1 SKEWING THROUGH THE TRANSCRIPTIONAL REPRESSION OF IL-12. 2022 17 368 33 AMYLOID BETA-MEDIATED EPIGENETIC ALTERATION OF INSULIN-LIKE GROWTH FACTOR BINDING PROTEIN 3 CONTROLS CELL SURVIVAL IN ALZHEIMER'S DISEASE. SWEDISH DOUBLE MUTATION (KM670/671NL) OF AMYLOID PRECURSOR PROTEIN (APP) IS REPORTED TO INCREASE TOXIC AMYLOID BETA (ABETA) PRODUCTION VIA ABERRANT CLEAVAGE AT THE BETA-SECRETASE SITE AND THEREBY CAUSE EARLY-ONSET ALZHEIMER'S DISEASE (AD). HOWEVER, THE UNDERLYING MOLECULAR MECHANISMS LEADING TO AD PATHOGENESIS REMAINS LARGELY UNKNOWN. PREVIOUSLY, OUR TRANSCRIPTOME SEQUENCE ANALYSES REVEALED GLOBAL EXPRESSIONAL MODIFICATIONS OF OVER 600 GENES IN APP-SWEDISH MUTANT-EXPRESSING H4 (H4-SW) CELLS COMPARED TO WILD TYPE H4 CELLS. INSULIN-LIKE GROWTH FACTOR BINDING PROTEIN 3 (IGFBP3) IS ONE GENE THAT SHOWED SIGNIFICANTLY DECREASED MRNA EXPRESSION IN H4-SW CELLS. IN THIS STUDY, WE INVESTIGATED THE FUNCTIONAL ROLE OF IGFBP3 IN AD PATHOGENESIS AND ELUCIDATED THE MECHANISMS REGULATING ITS EXPRESSION. WE OBSERVED DECREASED IGFBP3 EXPRESSION IN THE H4-SW CELL LINE AS WELL AS THE HIPPOCAMPUS OF AD MODEL TRANSGENIC MICE. TREATMENT WITH EXOGENOUS IGFBP3 PROTEIN INHIBITED ABETA1-42- INDUCED CELL DEATH AND CASPASE-3 ACTIVITY, WHEREAS SIRNA-MEDIATED SUPPRESSION OF IGFBP3 EXPRESSION INDUCED CELL DEATH AND CASPASE-3 CLEAVAGE. IN PRIMARY HIPPOCAMPAL NEURONS, ADMINISTRATION OF IGFBP3 PROTEIN BLOCKED APOPTOTIC CELL DEATH DUE TO ABETA1-42 TOXICITY. THESE DATA IMPLICATE A PROTECTIVE ROLE FOR IGFBP3 AGAINST ABETA1-42-MEDIATED APOPTOSIS. NEXT, WE INVESTIGATED THE REGULATORY MECHANISMS OF IGFBP3 EXPRESSION IN AD PATHOGENESIS. WE OBSERVED ABNORMAL IGFBP3 HYPERMETHYLATION WITHIN THE PROMOTER CPG ISLAND IN H4-SW CELLS. TREATMENT WITH THE DNA METHYLTRANSFERASE INHIBITOR 5-AZA-2'-DEOXYCYTIDINE RESTORED IGFBP3 EXPRESSION AT BOTH THE MRNA AND PROTEIN LEVELS. CHRONIC EXPOSURE TO ABETA1-42 INDUCED IGFBP3 HYPERMETHYLATION AT CPGS, PARTICULARLY AT LOCI -164 AND -173, AND SUBSEQUENTLY SUPPRESSED IGFBP3 EXPRESSION. THEREFORE, WE DEMONSTRATE THAT EXPRESSION OF ANTI-APOPTOTIC IGFBP3 IS REGULATED BY EPIGENETIC DNA METHYLATION, SUGGESTING A MECHANISM THAT CONTRIBUTES TO AD PATHOGENESIS. 2014 18 3945 33 LNCRNA IL21-AS1 INTERACTS WITH HNRNPU PROTEIN TO PROMOTE IL21 OVEREXPRESSION AND ABERRANT DIFFERENTIATION OF TFH CELLS IN SYSTEMIC LUPUS ERYTHEMATOSUS. BACKGROUND: THE ABERRANT DIFFERENTIATION OF T FOLLICULAR HELPER (TFH) CELLS PLAYS AN IMPORTANT ROLE IN THE PATHOGENESIS OF SYSTEMIC LUPUS ERYTHEMATOSUS (SLE). HOWEVER, THE MECHANISM OF REGULATING TFH CELLS DIFFERENTIATION REMAINS UNCLEAR. LONG NONCODING RNAS (LNCRNAS) ACT AS IMPORTANT REGULATORS IN THE PROCESSES OF INNATE AND ADAPTIVE IMMUNE RESPONSE. WHETHER LNCRNAS ARE INVOLVED IN REGULATING TFH CELL DIFFERENTIATION AND AUTOIMMUNE RESPONSES NEED TO BE FURTHER IDENTIFIED. METHODS: THE CHARACTERS AND FUNCTIONS OF HUMAN IL21-AS1 AND ITS MOUSE HOMOLOGOUS LNCRNA (MIL21-AS) WERE INVESTIGATED BY A SERIES OF BIOCHEMICAL ASSAYS AND CELL TRANSFECTION ASSAY. MIL21-AS1 REGULATING HUMORAL IMMUNE RESPONSE IN VIVO WAS EXPLORED BY KEYHOLE LIMPET HAEMOCYANIN (KLH) AND CHRONIC GRAFT VERSUS HOST DISEASE (CGVHD) MODEL. RESULTS: HUMAN IL21-AS1 AND ITS MOUSE HOMOLOGOUS LNCRNA (MIL21-AS) WERE IDENTIFIED AND CLONED. WE UNCOVERED THAT IL21-AS1 WAS HIGHLY EXPRESSED IN CD4(+) T CELLS OF SLE PATIENTS AND TFH CELLS, WHICH PROMOTED DIFFERENTIATION OF TFH CELLS. MECHANISTICALLY, IL21-AS1 BOUND HETEROGENEOUS NUCLEAR RIBONUCLEOPROTEIN U AND RECRUITED ACETYLTRANSFERASES CREB-BINDING PROTEIN TO THE PROMOTER OF IL21, LEADING TO THE TRANSCRIPTIONAL ACTIVATION OF IL21 AND TFH CELLS DIFFERENTIATION THROUGH INCREASING HISTONE H3 ACETYLATION LEVEL ON IL21 PROMOTER. MOREOVER, TFH PROPORTION AND ANTIBODIES PRODUCTION WERE SIGNIFICANTLY INCREASED IN MIL21-AS KNOCK-IN MICE IMMUNIZED WITH KLH. MIL21-AS1 OVEREXPRESSION ALSO EXACERBATED THE LUPUS-LIKE PHENOTYPE IN CGVHD MICE MODEL. CONCLUSIONS: OUR RESULTS DEMONSTRATE THAT IL21-AS1 ACTIVATES IL21 TRANSCRIPTION VIA EPIGENETIC MECHANISM TO PROMOTE GERMINAL CENTRE RESPONSE, ADDING INSIGHT INTO THE MOLECULAR REGULATION OF AUTOIMMUNE PATHOGENESIS AND PROVIDING A NOVEL TARGET FOR SLE TREATMENT. 2022 19 481 35 ARSENIC-INDUCED SUMOYLATION OF MUS81 IS INVOLVED IN REGULATING GENOMIC STABILITY. CHRONIC ENVIRONMENTAL EXPOSURE TO METAL TOXICANTS SUCH AS CHROMIUM AND ARSENIC IS CLOSELY RELATED TO THE DEVELOPMENT OF SEVERAL TYPES OF COMMON CANCERS. GENETIC AND EPIGENETIC STUDIES IN THE PAST DECADE REVEAL THAT POST-TRANSLATIONAL MODIFICATIONS OF HISTONES PLAY A ROLE IN METAL CARCINOGENESIS. HOWEVER, EXACT MOLECULAR MECHANISMS OF METAL CARCINOGENESIS REMAIN TO BE ELUCIDATED. IN THIS STUDY WE FOUND THAT AS(2)O(3), AN ENVIRONMENTAL METAL TOXICANT, UPREGULATED OVERALL MODIFICATIONS OF MANY CELLULAR PROTEINS BY SUMO2/3. SUMOYLATED PROTEINS FROM ARSENIC-TREATED CELLS CONSTITUTIVELY EXPRESSING HIS(6)-SUMO2 WERE PULLED DOWN BY NI-IDA RESIN UNDER DENATURING CONDITIONS. MASS SPECTROMETRIC ANALYSIS REVEALED OVER 100 PROTEINS THAT WERE POTENTIALLY MODIFIED BY SUMOYLATION. MUS81, A DNA ENDONUCLEASE INVOLVED IN HOMOLOGOUS RECOMBINATION REPAIR, WAS AMONG THE IDENTIFIED PROTEINS WHOSE SUMOYLATION WAS INCREASED AFTER TREATMENT WITH AS(2)O(3.) WE FURTHER SHOWED THAT K10 AND K524 WERE 2 LYSINE RESIDUES ESSENTIAL FOR MUS81 SUMOYLATION. MOREOVER, WE DEMONSTRATED THAT MUS81 SUMOYLATION IS IMPORTANT FOR NORMAL MITOTIC CHROMOSOME CONGRESSION AND THAT CELLS EXPRESSING SUMO-RESISTANT MUS81 MUTANTS DISPLAYED COMPROMISED DNA DAMAGE RESPONSES AFTER EXPOSURE TO METAL TOXINS SUCH AS CR(VI) AND ARSENIC. 2017 20 1668 31 DOWNREGULATION OF SOCS1 INCREASES INTERFERON-INDUCED ISGYLATION DURING DIFFERENTIATION OF INDUCED-PLURIPOTENT STEM CELLS TO HEPATOCYTES. BACKGROUND & AIMS: INCREASED EXPRESSION OF IFN-STIMULATED GENE 15 (ISG15) AND SUBSEQUENTLY INCREASED ISGYLATION ARE KEY FACTORS IN THE HOST RESPONSE TO VIRAL INFECTION. IN THIS STUDY, WE SOUGHT TO CHARACTERIZE THE EXPRESSION OF ISG15, ISGYLATION, AND ASSOCIATED ENZYMES AT EACH STAGE OF DIFFERENTIATION FROM INDUCED PLURIPOTENT STEM CELLS (IPSCS) TO HEPATOCYTES. METHODS: TO STUDY THE REGULATION OF ISGYLATION, WE UTILIZED PATIENT SAMPLES AND IN VITRO CELL CULTURE MODELS INCLUDING IPSCS, HEPATOCYTES-LIKE CELLS, IMMORTALIZED CELL LINES, AND PRIMARY HUMAN HEPATOCYTES. PROTEIN/MRNA EXPRESSION WERE MEASURED FOLLOWING TREATMENT WITH POLY(I:C), IFNALPHA AND HCV INFECTION. RESULTS: WHEN COMPARED TO HLCS, WE OBSERVED SEVERAL NOVEL ASPECTS OF THE ISGYLATION PATHWAY IN IPSCS. THESE INCLUDE A LOWER BASELINE EXPRESSION OF THE ISGYLATION-ACTIVATING ENZYME, UBE1L, A LACK OF IFN-INDUCED EXPRESSION OF THE ISGYLATION-CONJUGATION ENZYME UBE2L6, AN ATTENUATED ACTIVATION OF THE TRANSCRIPTION FACTOR STAT1 AND CONSTITUTIVE EXPRESSION OF SOCS1. ISGYLATION WAS OBSERVED IN IPSCS FOLLOWING DOWNREGULATION OF SOCS1, WHICH FACILITATED STAT1 ACTIVATION AND SUBSEQUENTLY INCREASED EXPRESSION OF UBE2L6. INTRIGUINGLY, HCV PERMISSIVE TRANSFORMED HEPATOMA CELL LINES DEMONSTRATED HIGHER INTRINSIC EXPRESSION OF SOCS1 AND WEAKER ISGYLATION FOLLOWING IFN TREATMENT. SOCS1 DOWNREGULATION IN HCV-INFECTED HUH 7.5.1 CELLS LED TO INCREASED ISGYLATION. CONCLUSIONS: HEREIN, WE SHOW THAT HIGH BASAL LEVELS OF SOCS1 INHIBIT STAT1 ACTIVATION AND SUBSEQUENTLY IFN-INDUCED UBE2L6 AND ISGYLATION IN IPSCS. FURTHERMORE, AS IPSCS DIFFERENTIATE INTO HEPATOCYTES, EPIGENETIC MECHANISMS REGULATE ISGYLATION BY MODIFYING UBE1L AND SOCS1 EXPRESSION LEVELS. OVERALL, THIS STUDY DEMONSTRATES THAT THE DEVELOPMENT OF CELL-INTRINSIC INNATE IMMUNITY DURING THE DIFFERENTIATION OF IPSCS TO HEPATOCYTES PROVIDES INSIGHT INTO CELL TYPE-SPECIFIC REGULATION OF HOST DEFENSE RESPONSES AND RELATED ONCOGENIC PROCESSES. IMPACT AND IMPLICATIONS: TO ELUCIDATE THE MECHANISM UNDERLYING REGULATION OF ISGYLATION, A KEY PROCESS IN THE INNATE IMMUNE RESPONSE, WE STUDIED CHANGES IN ISGYLATION-ASSOCIATED GENES AT THE DIFFERENT STAGES OF DIFFERENTIATION FROM IPSCS TO HEPATOCYTES. WE FOUND THAT HIGH BASAL LEVELS OF SOCS1 INHIBIT STAT1 ACTIVATION AND SUBSEQUENTLY IFN-INDUCED UBE2L6 AND ISGYLATION IN IPSCS. IMPORTANTLY, EPIGENETIC REGULATION OF SOCS1 AND SUBSEQUENTLY ISGYLATION MAY BE IMPORTANT FACTORS IN THE DEVELOPMENT OF CELL TYPE-SPECIFIC HOST DEFENSE RESPONSES IN HEPATOCYTES THAT SHOULD BE CONSIDERED WHEN STUDYING CHRONIC INFECTIONS AND ONCOGENIC PROCESSES IN THE LIVER. 2022