1 4876 110 OVEREXPRESSION OF ARGINASE 1 IS LINKED TO DNMT3A AND TET2 MUTATIONS IN LOWER-GRADE MYELODYSPLASTIC SYNDROMES AND CHRONIC MYELOMONOCYTIC LEUKEMIA. IMMUNE DYSREGULATION IS A COMMON FEATURE OF MYELODYSPLASTIC SYNDROMES (MDS) AND CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML), PARTICULARLY IN EARLY STAGES. HOWEVER, THE GENETIC BASIS REMAINS POORLY UNDERSTOOD. WE RECENTLY REPORTED THAT MACROPHAGES FROM MICE DEFICIENT IN TET METHYLCYTOSINE DIOXYGENASE 2 (TET2), A MODEL OF MDS/CMML, ARE HYPERINFLAMMATORY AND HAVE INCREASED EXPRESSION OF ARGINASE 1 (ARG1). IN MACROPHAGES AND MYELOID DERIVED SUPPRESSOR CELLS (MDSCS) EXPRESSION OF ARG1 CONTRIBUTES TO T-CELL SUPPRESSION AND IMMUNE EVASION BY L-ARGININE DEPLETION, IN THE SETTING OF CHRONIC INFLAMMATION AND CANCER. SINCE HUMAN MDS AND CMML ARE DRIVEN BY TET2 MUTATIONS AND ASSOCIATED WITH CHRONIC INFLAMMATION, WE HYPOTHESIZED THAT ARGINASE ENZYMATIC ACTIVITY AND ARG1 EXPRESSION WOULD BE INCREASED IN HUMAN MDS/CMML BONE MARROW. ELEVATED ARGINASE ACTIVITY WAS OBSERVED IN BONE MARROW MONONUCLEAR CELLS OF MDS AND CMML PATIENTS WITH LOWER-GRADE FEATURES. IMMUNOHISTOCHEMICAL STUDIES CONFIRMED THAT MYELOMONOCYTIC CELLS OVEREXPRESS ARG1. ADDITIONALLY, MUTATIONS IN THE EPIGENETIC REGULATORS TET2 AND DNMT3A CORRESPONDED TO HIGH ARG1 EXPRESSION AND ACTIVITY. THESE FINDINGS SUGGEST ARG1 IS A BIOMARKER OF IMMUNE DYSREGULATION IN EARLY MDS AND CMML. RECENT MURINE FINDINGS HAVE IMPLICATED TET2 AND DNMT3A IN REGULATION OF INNATE IMMUNITY. OUR STUDY SUGGESTS SIMILAR CHANGES MAY BE DRIVEN BY HUMAN TET2 AND DNMT3A MUTATIONS. 2018 2 3188 35 HBV-SPECIFIC CD8+ T-CELL TOLERANCE IN THE LIVER. HEPATITIS B VIRUS (HBV) REMAINS A LEADING CAUSE OF LIVER-RELATED MORBIDITY AND MORTALITY THROUGH CHRONIC HEPATITIS THAT MAY PROGRESS TO LIVER CIRRHOSIS AND CANCER. THE CENTRAL ROLE PLAYED BY HBV-SPECIFIC CD8+ T CELLS IN THE CLEARANCE OF ACUTE HBV INFECTION, AND HBV-RELATED LIVER INJURY IS NOW WELL ESTABLISHED. VIGOROUS, MULTIFUNCTIONAL CD8+ T CELL RESPONSES ARE USUALLY INDUCED IN MOST ADULT-ONSET HBV INFECTIONS, WHILE CHRONIC HEPATITIS B (CHB) IS CHARACTERIZED BY QUANTITATIVELY AND QUALITATIVELY WEAK HBV-SPECIFIC CD8+ T CELL RESPONSES. THE MOLECULAR BASIS OF THIS DICHOTOMY IS POORLY UNDERSTOOD. GENOMIC ANALYSIS OF DYSFUNCTIONAL HBV-SPECIFIC CD8+ T CELLS IN CHB PATIENTS AND VARIOUS MOUSE MODELS SUGGEST THAT MULTIFACETED MECHANISMS INCLUDING NEGATIVE SIGNALING AND METABOLIC ABNORMALITIES COOPERATIVELY ESTABLISH CD8+ T CELL DYSFUNCTION. IMMUNOREGULATORY CELL POPULATIONS IN THE LIVER, INCLUDING LIVER RESIDENT DENDRITIC CELLS (DCS), HEPATIC STELLATE CELLS (HSCS), MYELOID-DERIVED SUPPRESSOR CELLS (MDSCS), MAY CONTRIBUTE TO INTRAHEPATIC CD8+ T CELL DYSFUNCTION THROUGH THE PRODUCTION OF SOLUBLE MEDIATORS, SUCH AS ARGINASE, INDOLEAMINE 2,3-DIOXYGENASE (IDO) AND SUPPRESSIVE CYTOKINES AND THE EXPRESSION OF CO-INHIBITORY MOLECULES. A SERIES OF RECENT STUDIES WITH MOUSE MODELS OF HBV INFECTION SUGGEST THAT GENETIC AND EPIGENETIC CHANGES IN DYSFUNCTIONAL CD8+ T CELLS ARE THE MANIFESTATION OF PROLONGED ANTIGENIC STIMULATION, AS WELL AS THE ABSENCE OF CO-STIMULATORY OR CYTOKINE SIGNALING. THESE NEW FINDINGS MAY PROVIDE POTENTIAL NEW TARGETS FOR IMMUNOTHERAPY AIMING AT INVIGORATING HBV-SPECIFIC CD8+ T CELLS, WHICH HOPEFULLY CURES CHB. 2021 3 5983 51 TET2 RESTRAINS INFLAMMATORY GENE EXPRESSION IN MACROPHAGES. TET METHYLCYTOSINE DIOXYGENASE 2 (TET2) IS ONE OF THE EARLIEST AND MOST FREQUENTLY MUTATED GENES IN CLONAL HEMATOPOIESIS OF INDETERMINATE POTENTIAL (CHIP) AND MYELOID CANCERS, INCLUDING MYELODYSPLASTIC SYNDROMES (MDS) AND CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML). TET2 CATALYZES THE OXIDATION OF 5-METHYLCYTOSINE TO 5-HYDROXYMETHYLCYTOSINE, LEADING TO DNA DEMETHYLATION, AND ALSO AFFECTS TRANSCRIPTION BY RECRUITING HISTONE MODIFIERS. INACTIVATING TET2 MUTATIONS CAUSE EPIGENETIC DYSREGULATION, CLONAL HEMATOPOIETIC STEM CELL (HSC) DOMINANCE, AND MONOCYTIC LINEAGE SKEWING. HERE, WE FOUND THAT TET2 WAS THE MOST HIGHLY EXPRESSED TET ENZYME IN MURINE MACROPHAGE (MPHI) DIFFERENTIATION. TET2 TRANSCRIPTION WAS FURTHER INDUCED BY LIPOPOLYSACCHARIDE (LPS), BUT NOT INTERLEUKIN (IL)-4, STIMULATION, POTENTIALLY IN A NUCLEAR FACTOR KAPPABETA-DEPENDENT MANNER. TET2 LOSS DID NOT AFFECT EARLY LPS GENE RESPONSES IN VITRO, BUT INCREASED IL-1B, IL-6, AND ARGINASE 1 (ARG1) MRNA EXPRESSION AT LATER STAGES OF STIMULATION IN BONE-MARROW-DERIVED MPHIS (BMMPHIS). TET2-DEFICIENT PERITONEAL MPHIS, HOWEVER, DEMONSTRATED PROFOUND, CONSTITUTIVE EXPRESSION OF LPS-INDUCED GENES ASSOCIATED WITH AN INFLAMMATORY STATE IN VIVO. IN CONTRAST, TET2 DEFICIENCY DID NOT AFFECT ALTERNATIVE MPHI GENE EXPRESSION SIGNIFICANTLY IN RESPONSE TO IL-4. THESE RESULTS SUGGESTED IMPAIRED RESOLUTION OF INFLAMMATION IN THE ABSENCE OF TET2 BOTH IN VITRO AND IN VIVO. FOR THE FIRST TIME, WE ALSO DETECTED TET2 MUTATIONS IN BMMPHIS FROM MDS AND CMML PATIENTS AND ASSAYED THEIR EFFECTS ON LPS RESPONSES, INCLUDING THEIR POTENTIAL INFLUENCE ON HUMAN IL-6 EXPRESSION. OUR RESULTS SHOW THAT TET2 RESTRAINS INFLAMMATION IN MURINE MPHIS AND MICE, RAISING THE POSSIBILITY THAT LOSS OF TET2 FUNCTION IN MPHIS MAY ALTER THE IMMUNE ENVIRONMENT IN THE LARGE ELDERLY POPULATION WITH TET2-MUTANT CHIP AND IN TET2-MUTANT MYELOID CANCER PATIENTS. 2017 4 4567 36 MYELOID-DERIVED SUPPRESSOR CELL FUNCTION AND EPIGENETIC EXPRESSION EVOLVES OVER TIME AFTER SURGICAL SEPSIS. BACKGROUND: SEPSIS IS AN INCREASINGLY SIGNIFICANT CHALLENGE THROUGHOUT THE WORLD AS ONE OF THE MAJOR CAUSES OF PATIENT MORBIDITY AND MORTALITY. CENTRAL TO THE HOST IMMUNOLOGIC RESPONSE TO SEPSIS IS THE INCREASE IN CIRCULATING MYELOID-DERIVED SUPPRESSOR CELLS (MDSCS), WHICH HAVE BEEN DEMONSTRATED TO BE PRESENT AND INDEPENDENTLY ASSOCIATED WITH POOR LONG-TERM CLINICAL OUTCOMES. MDSCS ARE PLASTIC CELLS AND POTENTIALLY MODIFIABLE, PARTICULARLY THROUGH EPIGENETIC INTERVENTIONS. THE OBJECTIVE OF THIS STUDY WAS TO DETERMINE HOW THE SUPPRESSIVE PHENOTYPE OF MDSCS EVOLVES AFTER SEPSIS IN SURGICAL ICU PATIENTS, AS WELL AS TO IDENTIFY EPIGENETIC DIFFERENCES IN MDSCS THAT MAY EXPLAIN THESE CHANGES. METHODS: CIRCULATING MDSCS FROM 267 SURVIVORS OF SURGICAL SEPSIS WERE PHENOTYPED AT VARIOUS INTERVALS OVER 6 WEEKS, AND HIGHLY ENRICHED MDSCS FROM 23 OF THESE SAMPLES WERE CO-CULTURED WITH CD3/CD28-STIMULATED AUTOLOGOUS T CELLS. MICRORNA EXPRESSION FROM ENRICHED MDSCS WAS ALSO IDENTIFIED. RESULTS: WE OBSERVED THAT MDSC NUMBERS REMAIN SIGNIFICANTLY ELEVATED IN HOSPITALIZED SEPSIS SURVIVORS FOR AT LEAST 6 WEEKS AFTER THEIR INFECTION. HOWEVER, ONLY MDSCS OBTAINED AT AND BEYOND 14 DAYS POST-SEPSIS SIGNIFICANTLY SUPPRESSED T LYMPHOCYTE PROLIFERATION AND IL-2 PRODUCTION. THESE SAME MDSCS DISPLAYED UNIQUE EPIGENETIC (MIRNA) EXPRESSION PATTERNS COMPARED TO EARLIER TIME POINTS. CONCLUSIONS: WE CONCLUDE THAT IN SEPSIS SURVIVORS, IMMATURE MYELOID CELL NUMBERS ARE INCREASED BUT THE IMMUNE SUPPRESSIVE FUNCTION SPECIFIC TO MDSCS DEVELOPS OVER TIME, AND THIS IS ASSOCIATED WITH A SPECIFIC EPIGENOME. THESE FINDINGS MAY EXPLAIN THE CHRONIC AND PERSISTENT IMMUNE SUPPRESSION SEEN IN THESE SUBJECTS. 2019 5 5965 30 TEN-ELEVEN-TRANSLOCATION 2 (TET2) NEGATIVELY REGULATES HOMEOSTASIS AND DIFFERENTIATION OF HEMATOPOIETIC STEM CELLS IN MICE. THE TEN-ELEVEN-TRANSLOCATION 2 (TET2) GENE ENCODES A MEMBER OF TET FAMILY ENZYMES THAT ALTERS THE EPIGENETIC STATUS OF DNA BY OXIDIZING 5-METHYLCYTOSINE TO 5-HYDROXYMETHYLCYTOSINE (5HMC). SOMATIC LOSS-OF-FUNCTION MUTATIONS OF TET2 ARE FREQUENTLY OBSERVED IN PATIENTS WITH DIVERSE MYELOID MALIGNANCIES, INCLUDING MYELODYSPLASTIC SYNDROMES, MYELOPROLIFERATIVE NEOPLASMS, AND CHRONIC MYELOMONOCYTIC LEUKEMIA. BY ANALYZING MICE WITH TARGETED DISRUPTION OF THE TET2 CATALYTIC DOMAIN, WE SHOW HERE THAT TET2 IS A CRITICAL REGULATOR OF SELF-RENEWAL AND DIFFERENTIATION OF HEMATOPOIETIC STEM CELLS (HSCS). TET2 DEFICIENCY LED TO DECREASED GENOMIC LEVELS OF 5HMC AND AUGMENTED THE SIZE OF THE HEMATOPOIETIC STEM/PROGENITOR CELL POOL IN A CELL-AUTONOMOUS MANNER. IN COMPETITIVE TRANSPLANTATION ASSAYS, TET2-DEFICIENT HSCS WERE CAPABLE OF MULTILINEAGE RECONSTITUTION AND POSSESSED A COMPETITIVE ADVANTAGE OVER WILD-TYPE HSCS, RESULTING IN ENHANCED HEMATOPOIESIS INTO BOTH LYMPHOID AND MYELOID LINEAGES. IN VITRO, TET2 DEFICIENCY DELAYED HSC DIFFERENTIATION AND SKEWED DEVELOPMENT TOWARD THE MONOCYTE/MACROPHAGE LINEAGE. OUR DATA INDICATE THAT TET2 HAS A CRITICAL ROLE IN REGULATING THE EXPANSION AND FUNCTION OF HSCS, PRESUMABLY BY CONTROLLING 5HMC LEVELS AT GENES IMPORTANT FOR THE SELF-RENEWAL, PROLIFERATION, AND DIFFERENTIATION OF HSCS. 2011 6 3878 40 KDM6B OVEREXPRESSION ACTIVATES INNATE IMMUNE SIGNALING AND IMPAIRS HEMATOPOIESIS IN MICE. KDM6B IS AN EPIGENETIC REGULATOR THAT MEDIATES TRANSCRIPTIONAL ACTIVATION DURING DIFFERENTIATION, INCLUDING IN BONE MARROW (BM) HEMATOPOIETIC STEM AND PROGENITOR CELLS (HSPCS). OVEREXPRESSION OF KDM6B HAS BEEN REPORTED IN BM HSPCS OF PATIENTS WITH MYELODYSPLASTIC SYNDROMES (MDS) AND CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML). WHETHER THE OVEREXPRESSION OF KDM6B CONTRIBUTES TO THE PATHOGENESIS OF THESE DISEASES REMAINS TO BE ELUCIDATED. TO STUDY THIS, WE GENERATED A VAV-KDM6B MOUSE MODEL, WHICH OVEREXPRESSES KDM6B IN THE HEMATOPOIETIC COMPARTMENT. KDM6B OVEREXPRESSION ALONE LED TO MILD HEMATOPOIETIC PHENOTYPE, AND CHRONIC INNATE IMMUNE STIMULATION OF VAV-KDM6B MICE WITH THE TOLL-LIKE RECEPTOR (TLR) LIGAND LIPOPOLYSACCHARIDE (LPS) RESULTED IN SIGNIFICANT HEMATOPOIETIC DEFECTS. THESE DEFECTS RECAPITULATED FEATURES OF MDS AND CMML, INCLUDING LEUKOPENIA, DYSPLASIA, AND COMPROMISED REPOPULATING FUNCTION OF BM HSPCS. TRANSCRIPTOME STUDIES INDICATED THAT KDM6B OVEREXPRESSION ALONE COULD LEAD TO ACTIVATION OF DISEASE-RELEVANT GENES SUCH AS S100A9 IN BM HSPCS, AND WHEN COMBINED WITH INNATE IMMUNE STIMULATION, KDM6B OVEREXPRESSION RESULTED IN MORE PROFOUND OVEREXPRESSION OF INNATE IMMUNE AND DISEASE-RELEVANT GENES, INDICATING THAT KDM6B WAS INVOLVED IN THE ACTIVATION OF INNATE IMMUNE SIGNALING IN BM HSPCS. FINALLY, PHARMACOLOGIC INHIBITION OF KDM6B WITH THE SMALL MOLECULE INHIBITOR GSK-J4 AMELIORATED THE INEFFECTIVE HEMATOPOIESIS OBSERVED IN VAV-KDM6B MICE. THIS EFFECT WAS ALSO OBSERVED WHEN GSK-J4 WAS APPLIED TO THE PRIMARY BM HSPCS OF PATIENTS WITH MDS BY IMPROVING THEIR REPOPULATING FUNCTION. THESE RESULTS INDICATE THAT OVEREXPRESSION OF KDM6B MEDIATES ACTIVATION OF INNATE IMMUNE SIGNALS AND HAS A ROLE IN MDS AND CMML PATHOGENESIS, AND THAT KDM6B TARGETING HAS THERAPEUTIC POTENTIAL IN THESE MYELOID DISORDERS. 2018 7 3760 23 INTEGRATED SINGLE CELL ANALYSIS SHOWS CHRONIC ALCOHOL DRINKING DISRUPTS MONOCYTE DIFFERENTIATION IN THE BONE MARROW. CHRONIC HEAVY ALCOHOL DRINKING (CHD) REWIRES MONOCYTES AND MACROPHAGES TOWARD HEIGHTENED INFLAMMATORY STATES WITH COMPROMISED ANTIMICROBIAL DEFENSES THAT PERSIST AFTER 1-MONTH ABSTINENCE. TO DETERMINE WHETHER THESE CHANGES ARE MEDIATED THROUGH ALTERATIONS IN THE BONE MARROW NICHE, WE PROFILED MONOCYTES AND HEMATOPOIETIC STEM CELL PROGENITORS (HSCPS) FROM CHD RHESUS MACAQUES USING A COMBINATION OF FUNCTIONAL ASSAYS AND SINGLE CELL GENOMICS. CHD RESULTED IN TRANSCRIPTIONAL PROFILES CONSISTENT WITH INCREASED ACTIVATION AND INFLAMMATION WITHIN BONE MARROW RESIDENT MONOCYTES AND MACROPHAGES. FURTHERMORE, CHD RESULTED IN TRANSCRIPTIONAL SIGNATURES ASSOCIATED WITH INCREASED OXIDATIVE AND CELLULAR STRESS IN HSCP. DIFFERENTIATION OF HSCP IN VITRO REVEALED SKEWING TOWARD MONOCYTES EXPRESSING "NEUTROPHIL-LIKE" MARKERS WITH GREATER INFLAMMATORY RESPONSES TO BACTERIAL AGONISTS. FURTHER ANALYSES OF HSCPS SHOWED BROAD EPIGENETIC CHANGES THAT WERE IN LINE WITH EXACERBATED INFLAMMATORY RESPONSES WITHIN MONOCYTES AND THEIR PROGENITORS. IN SUMMARY, CHD ALTERS HSCPS IN THE BONE MARROW LEADING TO THE PRODUCTION OF MONOCYTES POISED TO GENERATE DYSREGULATED HYPER-INFLAMMATORY RESPONSES. 2023 8 5971 36 TET PROTEINS AND 5-METHYLCYTOSINE OXIDATION IN HEMATOLOGICAL CANCERS. DNA METHYLATION HAS PIVOTAL REGULATORY ROLES IN MAMMALIAN DEVELOPMENT, RETROTRANSPOSON SILENCING, GENOMIC IMPRINTING, AND X-CHROMOSOME INACTIVATION. CANCER CELLS DISPLAY HIGHLY DYSREGULATED DNA METHYLATION PROFILES CHARACTERIZED BY GLOBAL HYPOMETHYLATION IN CONJUNCTION WITH HYPERMETHYLATION OF PROMOTER CPG ISLANDS THAT PRESUMABLY LEAD TO GENOME INSTABILITY AND ABERRANT EXPRESSION OF TUMOR SUPPRESSOR GENES OR ONCOGENES. THE RECENT DISCOVERY OF TEN-ELEVEN-TRANSLOCATION (TET) FAMILY DIOXYGENASES THAT OXIDIZE 5MC TO 5-HYDROXYMETHYLCYTOSINE (5HMC), 5-FORMYLCYTOSINE (5FC), AND 5-CARBOXYLCYTOSINE (5CAC) IN DNA HAS LED TO PROFOUND PROGRESS IN UNDERSTANDING THE MECHANISM UNDERLYING DNA DEMETHYLATION. AMONG THE THREE TET GENES, TET2 RECURRENTLY UNDERGOES INACTIVATING MUTATIONS IN A WIDE RANGE OF MYELOID AND LYMPHOID MALIGNANCIES. TET2 FUNCTIONS AS A BONA FIDE TUMOR SUPPRESSOR PARTICULARLY IN THE PATHOGENESIS OF MYELOID MALIGNANCIES RESEMBLING CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) AND MYELODYSPLASTIC SYNDROMES (MDS) IN HUMAN. HERE WE REVIEW DIVERSE FUNCTIONS OF TET PROTEINS AND THE NOVEL EPIGENETIC MARKS THAT THEY GENERATE IN DNA METHYLATION/DEMETHYLATION DYNAMICS AND NORMAL AND MALIGNANT HEMATOPOIETIC DIFFERENTIATION. THE IMPACT OF TET2 INACTIVATION IN HEMATOPOIESIS AND VARIOUS MECHANISMS MODULATING THE EXPRESSION OR ACTIVITY OF TET PROTEINS ARE ALSO DISCUSSED. FURTHERMORE, WE ALSO PRESENT EVIDENCE THAT TET2 AND TET3 COLLABORATE TO SUPPRESS ABERRANT HEMATOPOIESIS AND HEMATOPOIETIC TRANSFORMATION. A DETAILED UNDERSTANDING OF THE NORMAL AND PATHOLOGICAL FUNCTIONS OF TET PROTEINS MAY PROVIDE NEW AVENUES TO DEVELOP NOVEL EPIGENETIC THERAPIES FOR TREATING HEMATOLOGICAL MALIGNANCIES. 2015 9 923 26 CHRONIC INFECTION DRIVES DNMT3A-LOSS-OF-FUNCTION CLONAL HEMATOPOIESIS VIA IFNGAMMA SIGNALING. AGE-RELATED CLONAL HEMATOPOIESIS (CH) IS A RISK FACTOR FOR MALIGNANCY, CARDIOVASCULAR DISEASE, AND ALL-CAUSE MORTALITY. SOMATIC MUTATIONS IN DNMT3A ARE DRIVERS OF CH, BUT DECADES MAY ELAPSE BETWEEN THE ACQUISITION OF A MUTATION AND CH, SUGGESTING THAT ENVIRONMENTAL FACTORS CONTRIBUTE TO CLONAL EXPANSION. WE TESTED WHETHER INFECTION PROVIDES SELECTIVE PRESSURE FAVORING THE EXPANSION OF DNMT3A MUTANT HEMATOPOIETIC STEM CELLS (HSCS) IN MOUSE CHIMERAS. WE CREATED DNMT3A-MOSAIC MICE BY TRANSPLANTING DNMT3A(-/-) AND WT HSCS INTO WT MICE AND OBSERVED THE SUBSTANTIAL EXPANSION OF DNMT3A(-/-) HSCS DURING CHRONIC MYCOBACTERIAL INFECTION. INJECTION OF RECOMBINANT IFNGAMMA ALONE WAS SUFFICIENT TO PHENOCOPY CH BY DNMT3A(-/-) HSCS UPON INFECTION. TRANSCRIPTIONAL AND EPIGENETIC PROFILING AND FUNCTIONAL STUDIES INDICATE REDUCED DIFFERENTIATION ASSOCIATED WITH WIDESPREAD METHYLATION ALTERATIONS, AND REDUCED SECONDARY STRESS-INDUCED APOPTOSIS ACCOUNTS FOR DNMT3A(-/-) CLONAL EXPANSION DURING INFECTION. DNMT3A MUTANT HUMAN HSCS SIMILARLY EXHIBIT DEFECTIVE IFNGAMMA-INDUCED DIFFERENTIATION. WE THUS DEMONSTRATE THAT IFNGAMMA SIGNALING INDUCED DURING CHRONIC INFECTION CAN DRIVE DNMT3A-LOSS-OF-FUNCTION CH. 2021 10 379 25 AN EPIGENETIC MECHANISM FOR HIGH, SYNERGISTIC EXPRESSION OF INDOLEAMINE 2,3-DIOXYGENASE 1 (IDO1) BY COMBINED TREATMENT WITH ZEBULARINE AND IFN-GAMMA: POTENTIAL THERAPEUTIC USE IN AUTOIMMUNE DISEASES. IDO1 CAN BE INDUCED BY INTERFERON GAMMA (IFN-GAMMA) IN MULTIPLE CELL TYPES. WE HAVE EARLIER DESCRIBED THAT THE DNA METHYLTRANSFERASE INHIBITOR ZEBULARINE ALSO INDUCES IDO1 IN SEVERAL RAT CELL CLONES. WE NOW DESCRIBE A SYNERGISTIC INDUCTION OF IDO1 EXPRESSION BY IFN-GAMMA AND ZEBULARINE. TO ELUCIDATE THE MECHANISM OF THE IDO1 INDUCTION WE HAVE STUDIED THE METHYLATION STATUS IN THE PROMOTER REGION OF THE IDO1 GENE FROM BOTH HUMAN MONOCYTIC THP-1 CELLS AND H1D2 RAT COLON CANCER CELLS. INTERESTINGLY, THE IDO1 PROMOTER IS HYPERMETHYLATED AND IFN-GAMMA IS SHOWN TO INDUCE A SIGNIFICANT DEMETHYLATION. THE SYNERGISM IN EFFECT OF ZEBULARINE AND IFN-GAMMA ON IDO1 EXPRESSION IS PARALLELED BY A SIMILAR SYNERGISTIC EFFECT ON EXPRESSION OF TWO OTHER IFN-GAMMA-RESPONSIVE GENES, THE TRANSCRIPTION FACTORS STAT1 AND IRF1 WITH BINDING SITES IN THE IDO1 PROMOTER REGION. THE DEMONSTRATED SYNERGISTIC ACTIVATION OF IDO1 EXPRESSION HAS IMPLICATIONS IN RELATION TO THERAPEUTIC INDUCTION OF IMMUNOSUPPRESSION IN AUTOIMMUNITY AND CHRONIC INFLAMMATION. 2012 11 5425 33 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 12 3759 26 INTEGRATED SINGLE CELL ANALYSIS SHOWS CHRONIC ALCOHOL DRINKING DISRUPTS MONOCYTE DIFFERENTIATION IN THE BONE MARROW NICHE. CHRONIC ALCOHOL DRINKING REWIRES CIRCULATING MONOCYTES AND TISSUE-RESIDENT MACROPHAGES TOWARDS HEIGHTENED INFLAMMATORY STATES WITH COMPROMISED ANTI-MICROBIAL DEFENSES. AS THESE EFFECTS REMAIN CONSISTENT IN SHORT-LIVED MONOCYTES AFTER A 1-MONTH ABSTINENCE PERIOD IT IS UNCLEAR WHETHER THESE CHANGES ARE RESTRICTED TO THE PERIPHERY OR MEDIATED THROUGH ALTERATIONS IN THE PROGENITOR NICHE. TO TEST THIS HYPOTHESIS, WE PROFILED MONOCYTES/MACROPHAGES AND HEMATOPOIETIC STEM CELL PROGENITORS (HSCP) OF THE BONE MARROW COMPARTMENT FROM RHESUS MACAQUES AFTER 12 MONTHS OF ETHANOL CONSUMPTION USING A COMBINATION OF FUNCTIONAL ASSAYS AND SINGLE CELL GENOMICS. BONE MARROW-RESIDENT MONOCYTES/MACROPHAGES FROM ETHANOL-CONSUMING ANIMALS EXHIBITED HEIGHTENED INFLAMMATION. DIFFERENTIATION OF HSCP IN VITRO REVEALED SKEWING TOWARDS MONOCYTES EXPRESSING NEUTROPHIL-LIKE MARKERS WITH HEIGHTENED INFLAMMATORY RESPONSES TO BACTERIAL AGONISTS. SINGLE CELL TRANSCRIPTIONAL ANALYSIS OF HSCPS SHOWED REDUCED PROLIFERATION BUT INCREASED INFLAMMATORY MARKERS IN MATURE MYELOID PROGENITORS. WE OBSERVED TRANSCRIPTIONAL SIGNATURES ASSOCIATED WITH INCREASED OXIDATIVE AND CELLULAR STRESS AS WELL AS OXIDATIVE PHOSPHORYLATION IN IMMATURE AND MATURE MYELOID PROGENITORS. SINGLE CELL ANALYSIS OF THE CHROMATIN LANDSCAPE SHOWED ALTERED DRIVERS OF DIFFERENTIATION IN MONOCYTES AND PROGENITORS. COLLECTIVELY, THESE DATA INDICATE THAT CHRONIC ETHANOL DRINKING RESULTS IN REMODELING OF THE TRANSCRIPTIONAL AND EPIGENETIC LANDSCAPES OF THE BONE MARROW COMPARTMENT LEADING TO ALTERED FUNCTIONS IN THE PERIPHERY. 2023 13 3246 22 HEPATITIS B VIRUS (HBV) INDUCES THE EXPRESSION OF INTERLEUKIN-8 THAT IN TURN REDUCES HBV SENSITIVITY TO INTERFERON-ALPHA. HIGH LEVELS OF SERUM INTERLEUKIN-8 (IL-8) HAVE BEEN DETECTED IN CHRONIC HEPATITIS B (CHB) PATIENTS DURING EPISODES OF HEPATITIS FLARES. WE INVESTIGATED WHETHER HEPATITIS B VIRUS (HBV) MAY DIRECTLY INDUCE IL-8 PRODUCTION AND WHETHER IL-8 MAY ANTAGONIZE INTERFERON-ALPHA (IFN-ALPHA) ANTIVIRAL ACTIVITY AGAINST HBV. WE SHOWED THAT CHB PATIENTS HAD SIGNIFICANTLY HIGHER IL-8 LEVELS BOTH IN SERUM AND IN LIVER TISSUE THAN CONTROLS. IN HBV-REPLICATING HEPG2 CELLS, IL-8 TRANSCRIPTION WAS SIGNIFICANTLY ACTIVATED. AP-1, C/EBP AND NF-KB TRANSCRIPTION FACTORS WERE CONCURRENTLY NECESSARY FOR MAXIMUM IL-8 INDUCTION. MOREOVER, HBX VIRAL PROTEIN WAS RECRUITED ONTO THE IL-8 PROMOTER AND THIS WAS PARALLELED BY IL8-BOUND HISTONE HYPERACETYLATION AND BY ACTIVE RECRUITMENT OF TRANSCRIPTIONAL COACTIVATORS. INHIBITION OF IL-8 INCREASES THE ANTIVIRAL ACTIVITY OF IFN-ALPHA AGAINST HBV. OUR RESULTS INDICATE THAT HBV ACTIVATES IL-8 GENE EXPRESSION BY TARGETING THE EPIGENETIC REGULATION OF THE IL-8 PROMOTER AND THAT IL-8 MAY CONTRIBUTE TO REDUCE HBV SENSITIVITY TO IFN-ALPHA. 2013 14 4838 34 ONCOGENIC N-RAS AND TET2 HAPLOINSUFFICIENCY COLLABORATE TO DYSREGULATE HEMATOPOIETIC STEM AND PROGENITOR CELLS. CONCURRENT GENETIC LESIONS EXIST IN A MAJORITY OF PATIENTS WITH HEMATOLOGIC MALIGNANCIES. AMONG THESE, SOMATIC MUTATIONS THAT ACTIVATE RAS ONCOGENES AND INACTIVATE THE EPIGENETIC MODIFIER TEN-ELEVEN TRANSLOCATION 2 (TET2) FREQUENTLY CO-OCCUR IN HUMAN CHRONIC MYELOMONOCYTIC LEUKEMIAS (CMMLS) AND ACUTE MYELOID LEUKEMIAS, SUGGESTING A COOPERATIVITY IN MALIGNANT TRANSFORMATION. TO TEST THIS, WE APPLIED A CONDITIONAL MURINE MODEL THAT ENDOGENOUSLY EXPRESSED ONCOGENIC NRAS(G12D) AND MONOALLELIC LOSS OF TET2 AND EXPLORED THE COLLABORATIVE ROLE SPECIFICALLY WITHIN HEMATOPOIETIC STEM AND PROGENITOR CELLS (HSPCS) AT DISEASE INITIATION. WE DEMONSTRATE THAT THE 2 MUTATIONS COLLABORATED TO ACCELERATE A TRANSPLANTABLE CMML-LIKE DISEASE IN VIVO, WITH AN OVERALL SHORTENED SURVIVAL AND INCREASED DISEASE PENETRANCE COMPARED WITH SINGLE MUTANTS. AT PRELEUKEMIC STAGE, N-RAS(G12D) AND TET2 HAPLOINSUFFICIENCY TOGETHER INDUCED BALANCED HEMATOPOIETIC STEM CELL (HSC) PROLIFERATION AND ENHANCED COMPETITIVENESS. NRAS(G12D/+)/TET2(+/-) HSCS DISPLAYED INCREASED SELF-RENEWAL IN PRIMARY AND SECONDARY TRANSPLANTATIONS, WITH SIGNIFICANTLY HIGHER RECONSTITUTION THAN SINGLE MUTANTS. STRIKINGLY, THE 2 MUTATIONS TOGETHER CONFERRED LONG-TERM RECONSTITUTION AND SELF-RENEWAL POTENTIAL TO MULTIPOTENT PROGENITORS, A POOL OF CELLS THAT USUALLY HAVE LIMITED SELF-RENEWAL COMPARED WITH HSCS. MOREOVER, HSPCS FROM NRAS(G12D/+)/TET2(+/-) MICE DISPLAYED INCREASED CYTOKINE SENSITIVITY IN RESPONSE TO THROMBOPOIETIN. THEREFORE, OUR STUDIES ESTABLISH A NOVEL TRACTABLE CMML MODEL AND PROVIDE INSIGHTS INTO HOW DYSREGULATED SIGNALING PATHWAYS AND EPIGENETIC MODIFIERS COLLABORATE TO MODULATE HSPC FUNCTION AND PROMOTE LEUKEMOGENESIS. 2018 15 1184 23 COOPERATIVE EPIGENETIC REMODELING BY TET2 LOSS AND NRAS MUTATION DRIVES MYELOID TRANSFORMATION AND MEK INHIBITOR SENSITIVITY. MUTATIONS IN EPIGENETIC MODIFIERS AND SIGNALING FACTORS OFTEN CO-OCCUR IN MYELOID MALIGNANCIES, INCLUDING TET2 AND NRAS MUTATIONS. CONCURRENT TET2 LOSS AND NRAS(G12D) EXPRESSION IN HEMATOPOIETIC CELLS INDUCED MYELOID TRANSFORMATION, WITH A FULLY PENETRANT, LETHAL CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML), WHICH WAS SERIALLY TRANSPLANTABLE. TET2 LOSS AND NRAS MUTATION COOPERATIVELY LED TO DECREASE IN NEGATIVE REGULATORS OF MITOGEN-ACTIVATED PROTEIN KINASE (MAPK) ACTIVATION, INCLUDING SPRY2, THEREBY CAUSING SYNERGISTIC ACTIVATION OF MAPK SIGNALING BY EPIGENETIC SILENCING. TET2/NRAS DOUBLE-MUTANT LEUKEMIA SHOWED PREFERENTIAL SENSITIVITY TO MAPK KINASE (MEK) INHIBITION IN BOTH MOUSE MODEL AND PATIENT SAMPLES. THESE DATA PROVIDE INSIGHTS INTO HOW EPIGENETIC AND SIGNALING MUTATIONS COOPERATE IN MYELOID TRANSFORMATION AND PROVIDE A RATIONALE FOR MECHANISM-BASED THERAPY IN CMML PATIENTS WITH THESE HIGH-RISK GENETIC LESIONS. 2018 16 5978 26 TET2 AND TET3 IN B CELLS ARE REQUIRED TO REPRESS CD86 AND PREVENT AUTOIMMUNITY. A CONTRIBUTION OF EPIGENETIC MODIFICATIONS TO B CELL TOLERANCE HAS BEEN PROPOSED BUT NOT DIRECTLY TESTED. HERE WE REPORT THAT DEFICIENCY OF TEN-ELEVEN TRANSLOCATION (TET) DNA DEMETHYLASE FAMILY MEMBERS TET2 AND TET3 IN B CELLS LED TO HYPERACTIVATION OF B AND T CELLS, AUTOANTIBODY PRODUCTION AND LUPUS-LIKE DISEASE IN MICE. MECHANISTICALLY, IN THE ABSENCE OF TET2 AND TET3, DOWNREGULATION OF CD86, WHICH NORMALLY OCCURS FOLLOWING CHRONIC EXPOSURE OF SELF-REACTIVE B CELLS TO SELF-ANTIGEN, DID NOT TAKE PLACE. THE IMPORTANCE OF DYSREGULATED CD86 EXPRESSION IN TET2- AND TET3-DEFICIENT B CELLS WAS FURTHER DEMONSTRATED BY THE RESTRICTION, ALBEIT NOT COMPLETE, ON ABERRANT T AND B CELL ACTIVATION FOLLOWING ANTI-CD86 BLOCKADE. TET2- AND TET3-DEFICIENT B CELLS HAD DECREASED ACCUMULATION OF HISTONE DEACETYLASE 1 (HDAC1) AND HDAC2 AT THE CD86 LOCUS. THUS, OUR FINDINGS SUGGEST THAT TET2- AND TET3-MEDIATED CHROMATIN MODIFICATION PARTICIPATES IN REPRESSION OF CD86 ON CHRONICALLY STIMULATED SELF-REACTIVE B CELLS, WHICH CONTRIBUTES, AT LEAST IN PART, TO PREVENTING AUTOIMMUNITY. 2020 17 6111 19 THE EPIGENETIC ARCHITECTURE AT GENE PROMOTERS DETERMINES CELL TYPE-SPECIFIC LPS TOLERANCE. SYNOVIAL FIBROBLASTS (SF) DRIVE INFLAMMATION AND JOINT DESTRUCTION IN CHRONIC ARTHRITIS. HERE WE SHOW THAT SF POSSESS A DISTINCT TYPE OF LPS TOLERANCE COMPARED TO MACROPHAGES AND OTHER TYPES OF FIBROBLASTS. IN SF AND DERMAL FIBROBLASTS, GENES THAT WERE NON-TOLERIZABLE AFTER REPEATED LPS STIMULATION INCLUDED PRO-INFLAMMATORY CYTOKINES, CHEMOKINES AND MATRIX METALLOPROTEINASES, WHEREAS ANTI-VIRAL GENES WERE TOLERIZABLE. IN MACROPHAGES, ALL MEASURED GENES WERE TOLERIZABLE, WHEREAS IN GINGIVAL AND FORESKIN FIBROBLASTS THESE GENES WERE NON-TOLERIZABLE. REPEATED STIMULATION OF SF WITH LPS RESULTED IN LOSS OF ACTIVATING HISTONE MARKS ONLY IN PROMOTERS OF TOLERIZABLE GENES. THE EPIGENETIC LANDSCAPE AT PROMOTERS OF TOLERIZABLE GENES WAS SIMILAR IN UNSTIMULATED SF AND MONOCYTES, WHEREAS THE BASAL CONFIGURATION OF HISTONE MARKS PROFOUNDLY DIFFERED IN GENES THAT WERE NON-TOLERIZABLE IN SF ONLY. OUR DATA SUGGEST THAT THE EPIGENETIC CONFIGURATION AT GENE PROMOTERS REGULATES CELL-SPECIFIC LPS-INDUCED RESPONSES AND PRIMES SF TO SUSTAIN THEIR INFLAMMATORY RESPONSE IN CHRONIC ARTHRITIS. 2017 18 2277 30 EPIGENETIC REGULATION BY ASXL1 IN MYELOID MALIGNANCIES. MYELOID MALIGNANCIES ARE CLONAL HEMATOPOIETIC DISORDERS THAT ARE COMPRISED OF A SPECTRUM OF GENETICALLY HETEROGENEOUS DISORDERS, INCLUDING MYELODYSPLASTIC SYNDROMES (MDS), MYELOPROLIFERATIVE NEOPLASMS (MPN), CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML), AND ACUTE MYELOID LEUKEMIA (AML). MYELOID MALIGNANCIES ARE CHARACTERIZED BY EXCESSIVE PROLIFERATION, ABNORMAL SELF-RENEWAL, AND/OR DIFFERENTIATION DEFECTS OF HEMATOPOIETIC STEM CELLS (HSCS) AND MYELOID PROGENITOR CELLS HEMATOPOIETIC STEM/PROGENITOR CELLS (HSPCS). MYELOID MALIGNANCIES CAN BE CAUSED BY GENETIC AND EPIGENETIC ALTERATIONS THAT PROVOKE KEY CELLULAR FUNCTIONS, SUCH AS SELF-RENEWAL, PROLIFERATION, BIASED LINEAGE COMMITMENT, AND DIFFERENTIATION. ADVANCES IN NEXT-GENERATION SEQUENCING LED TO THE IDENTIFICATION OF MULTIPLE MUTATIONS IN MYELOID NEOPLASMS, AND MANY NEW GENE MUTATIONS WERE IDENTIFIED AS KEY FACTORS IN DRIVING THE PATHOGENESIS OF MYELOID MALIGNANCIES. THE POLYCOMB PROTEIN ASXL1 WAS IDENTIFIED TO BE FREQUENTLY MUTATED IN ALL FORMS OF MYELOID MALIGNANCIES, WITH MUTATIONAL FREQUENCIES OF 20%, 43%, 10%, AND 20% IN MDS, CMML, MPN, AND AML, RESPECTIVELY. SIGNIFICANTLY, ASXL1 MUTATIONS ARE ASSOCIATED WITH A POOR PROGNOSIS IN ALL FORMS OF MYELOID MALIGNANCIES. THE FACT THAT ASXL1 MUTATIONS ARE ASSOCIATED WITH POOR PROGNOSIS IN PATIENTS WITH CMML, MDS, AND AML, POINTS TO THE POSSIBILITY THAT ASXL1 MUTATION IS A KEY FACTOR IN THE DEVELOPMENT OF MYELOID MALIGNANCIES. THIS REVIEW SUMMARIZES THE RECENT ADVANCES IN UNDERSTANDING MYELOID MALIGNANCIES WITH A SPECIFIC FOCUS ON ASXL1 MUTATIONS. 2023 19 6780 29 [BLASTIC PLASMACYTOID DENDRITIC CELL NEOPLASM ACCOMPANIED BY CHRONIC MYELOMONOCYTIC LEUKEMIA SUCCESSFULLY TREATED WITH AZACITIDINE]. BLASTIC PLASMACYTOID DENDRITIC CELL NEOPLASM (BPDCN) IS A RARE DISEASE THAT DEVELOPS WITH A SKIN LESION AND IS OFTEN ACCOMPANIED BY LEUKEMIC TRANSFORMATION. THE NORMAL COUNTERPARTS OF BPDCN TUMOR CELLS ARE PROGENITORS OF PLASMACYTOID DENDRITIC CELLS, WHEREAS THE ORIGINS ARE THOUGHT TO BE HEMATOPOIETIC STEM CELLS. APPROXIMATELY 10%-20% OF BPDCN PATIENTS DEVELOP OTHER HEMATOLOGIC MALIGNANCIES, INCLUDING CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML). MUTATIONS IN EPIGENETIC REGULATORS ARE FREQUENTLY OBSERVED IN BOTH BPDCN AND CMML TUMORS. AZACITIDINE, A DRUG THAT TARGETS EPIGENETIC DYSREGULATION, IS KNOWN TO BE AN EFFECTIVE TREATMENT FOR CMML. HOWEVER, IT HAS BEEN USED IN FEW BPDCN PATIENTS. HERE, WE REPORT A BPDCN PATIENT WITH SKIN LESIONS, BONE MARROW INFILTRATION, AND LYMPHADENOPATHY. CMML ALSO DEVELOPED DURING THE COURSE OF BPDCN. AZACITIDINE HAD POSITIVE EFFECTS ON CMML; HOWEVER, BPDCN AGGRESSIVELY RELAPSED DURING TREATMENT. TWO TET2 MUTATIONS WERE FOUND IN BOTH BPDCN AND CMML TUMORS; ONE OF WHICH WAS COMMONLY IDENTIFIED IN BOTH TUMORS. 2018 20 2302 29 EPIGENETIC REGULATION OF CANCER STEM CELL MARKER CD133 BY TRANSFORMING GROWTH FACTOR-BETA. HEPATOCELLULAR CARCINOMA (HCC) IS THE THIRD LEADING CAUSE OF CANCER MORTALITY WORLDWIDE. CD133, A TRANSMEMBRANE GLYCOPROTEIN, IS AN IMPORTANT CELL SURFACE MARKER FOR BOTH STEM CELLS AND CANCER STEM CELLS IN VARIOUS TISSUES INCLUDING LIVER. CD133 EXPRESSION HAS BEEN RECENTLY LINKED TO POOR PROGNOSIS IN HCC PATIENTS. CD133+ LIVER CANCER CELLS ARE CHARACTERIZED BY RESISTANCE TO CHEMOTHERAPY, SELF-RENEWAL, MULTILINEAGE POTENTIAL, INCREASED COLONY FORMATION, AND IN VIVO CANCER INITIATION AT LIMITED DILUTION. RECENT STUDIES DEMONSTRATE THAT CD133 EXPRESSION IS REGULATED BY DNA METHYLATION. IN THIS STUDY, WE EXPLORED THE ROLE OF TRANSFORMING GROWTH FACTOR BETA (TGFBETA), A MULTIFUNCTIONAL CYTOKINE THAT PLAYS A CRITICAL ROLE IN CHRONIC LIVER INJURY, IN THE REGULATION OF CD133 EXPRESSION. TGFBETA1 IS CAPABLE OF UP-REGULATING CD133 EXPRESSION SPECIFICALLY WITHIN THE HUH7 HCC CELL LINE IN A TIME- AND DOSE-DEPENDENT MANNER. MOST IMPORTANT, TGFBETA1-INDUCED CD133+ HUH7 CELLS DEMONSTRATE INCREASED TUMOR INITIATION IN VIVO. FORCED EXPRESSION OF INHIBITORY SMADS, INCLUDING SMAD6 AND SMAD7, ATTENUATED TGFBETA1-INDUCED CD133 EXPRESSION. WITHIN CD133- HUH7 CELLS, TGFBETA1 STIMULATION INHIBITED THE EXPRESSION OF DNA METHYLTRANSFERASES (DNMT) 1 AND DNMT3BETA, WHICH ARE CRITICAL IN THE MAINTENANCE OF REGIONAL DNA METHYLATION, AND GLOBAL DNMT ACTIVITY IN CD133- HUH7 CELLS WAS INHIBITED BY TGFBETA1. DNMT3BETA INHIBITION BY TGFBETA1 WAS PARTIALLY RESCUED WITH OVEREXPRESSION OF INHIBITORY SMADS. LASTLY, TGFBETA1 TREATMENT LED TO SIGNIFICANT DEMETHYLATION IN CD133 PROMOTER-1 IN CD133- HUH7 CELLS. CONCLUSION: TGFBETA1 IS ABLE TO REGULATE CD133 EXPRESSION THROUGH INHIBITION OF DNMT1 AND DNMT3BETA EXPRESSION AND SUBSEQUENT DEMETHYLATION OF PROMOTER-1. TGFBETA1-INDUCED CD133+ HUH7 CELLS ARE TUMORIGENIC. THE MECHANISM BY WHICH TGFBETA INDUCES CD133 EXPRESSION IS PARTIALLY DEPENDENT ON THE SMADS PATHWAY. 2010