1 2185 134 EPIGENETIC MECHANISMS UNDERLYING HIV-INFECTION INDUCED SUSCEPTIBILITY OF CD4+ T CELLS TO ENHANCED ACTIVATION-INDUCED FASL EXPRESSION AND CELL DEATH. BACKGROUND: CHRONIC IMMUNE ACTIVATION AND CD4 T CELL DEPLETION ARE SIGNIFICANT PATHOGENIC FEATURES OF HIV INFECTION. EXPRESSION OF FAS LIGAND (FASL), A KEY MEDIATOR OF ACTIVATION-INDUCED CELL DEATH IN T CELLS, IS ELEVATED IN PEOPLE LIVING WITH HIV-1 INFECTION (PLWH). HOWEVER, THE EPIGENETIC MECHANISMS UNDERLYING THE ENHANCED INDUCTION OF FASL EXPRESSION IN CD4 T LYMPHOCYTES IN PLWH ARE NOT COMPLETELY ELUCIDATED. HENCE, THE CURRENT WORK EXAMINED THE EFFECT OF HIV INFECTION ON FASL PROMOTER-ASSOCIATED HISTONE MODIFICATIONS AND TRANSCRIPTIONAL REGULATION IN CD4 T LYMPHOCYTES IN PLWH. METHOD: FLOW CYTOMETRIC ANALYSIS WAS PERFORMED TO EXAMINE THE FAS-FASL EXPRESSION ON TOTAL CD4 T CELLS AND NAIVE/MEMORY CD4 T CELL SUBSETS. EPIGENETIC FASL PROMOTER HISTONE MODIFICATIONS WERE INVESTIGATED BY CHROMATIN IMMUNOPRECIPITATION-QUANTITATIVE REAL-TIME POLYMERASE CHAIN REACTION ANALYSIS USING FRESHLY ISOLATED TOTAL CD4 T LYMPHOCYTES FROM HIV-1 INFECTED AND NONINFECTED INDIVIDUALS. RESULTS: ALL NAIVE/MEMORY CD4 T CELL SUBSETS FROM PLWH SHOWED MARKEDLY GREATER FREQUENCY OF FASL EXPRESSION. NOTABLY, EXAMINATION OF FUNCTIONAL OUTCOME OF FASL/FAS CO-EXPRESSION DEMONSTRATED THE PREFERENTIAL SUSCEPTIBILITY OF TCM AND TEM SUBSETS TO ACTIVATION-INDUCED APOPTOSIS. IMPORTANTLY, THESE CD4 T CELLS COLLECTIVELY DEMONSTRATED A DISTINCT FASL PROMOTER HISTONE PROFILE INVOLVING A COORDINATED CROSS-TALK BETWEEN HISTONE H3 MODIFICATIONS LEADING TO ENHANCED FASL GENE EXPRESSION. SPECIFICALLY, LEVELS OF TRANSCRIPTIONALLY PERMISSIVE HISTONE H3K4-TRIMETHYLATION (H3K4ME3) AND HISTONE H3K9-ACETYLATION (H3K9AC) WERE INCREASED, WITH A CONCOMITANT DECREASE IN THE REPRESSIVE H3K9-TRIMETHYLATION (H3K9ME3). CONCLUSION: THE PRESENT WORK DEMONSTRATES THAT EPIGENETIC MECHANISMS INVOLVING PROMOTER-HISTONE MODIFICATIONS REGULATE TRANSCRIPTIONAL COMPETENCE AND FASL EXPRESSION IN CD4 T CELLS FROM PLWH AND RENDER THEM SUSCEPTIBLE TO ACTIVATION-INDUCED CELL DEATH. 2021 2 5081 30 PI3KDELTA COORDINATES TRANSCRIPTIONAL, CHROMATIN, AND METABOLIC CHANGES TO PROMOTE EFFECTOR CD8(+) T CELLS AT THE EXPENSE OF CENTRAL MEMORY. PATIENTS WITH ACTIVATED PHOSPHATIDYLINOSITOL 3-KINASE DELTA (PI3KDELTA) SYNDROME (APDS) PRESENT WITH SINOPULMONARY INFECTIONS, LYMPHADENOPATHY, AND CYTOMEGALVIRUS (CMV) AND/OR EPSTEIN-BARR VIRUS (EBV) VIREMIA, YET WHY PATIENTS FAIL TO CLEAR CERTAIN CHRONIC VIRAL INFECTIONS REMAINS INCOMPLETELY UNDERSTOOD. USING PATIENT SAMPLES AND A MOUSE MODEL (PIK3CD(E1020K/+) MICE), WE DEMONSTRATE THAT, UPON ACTIVATION, PIK3CD(E1020K/+) CD8(+) T CELLS EXHIBIT EXAGGERATED FEATURES OF EFFECTOR POPULATIONS BOTH IN VITRO AND AFTER VIRAL INFECTION THAT ARE ASSOCIATED WITH INCREASED FAS-MEDIATED APOPTOSIS DUE TO SUSTAINED FOXO1 PHOSPHORYLATION AND FASL DEREPRESSION, ENHANCED MTORC1 AND C-MYC SIGNATURES, METABOLIC PERTURBATIONS, AND AN ALTERED CHROMATIN LANDSCAPE. CONVERSELY, PIK3CD(E1020K/+) CD8(+) CELLS FAIL TO SUSTAIN EXPRESSION OF PROTEINS CRITICAL FOR CENTRAL MEMORY, INCLUDING TCF1. STRIKINGLY, ACTIVATED PIK3CD(E1020K/+) CD8(+) CELLS EXHIBIT ALTERED TRANSCRIPTIONAL AND EPIGENETIC CIRCUITS CHARACTERIZED BY PRONOUNCED INTERLEUKIN-2 (IL-2)/STAT5 SIGNATURES AND HEIGHTENED IL-2 RESPONSES THAT PREVENT DIFFERENTIATION TO MEMORY-LIKE CELLS IN IL-15. OUR DATA POSITION PI3KDELTA AS INTEGRATING MULTIPLE SIGNALING NODES THAT PROMOTE CD8(+) T CELL EFFECTOR DIFFERENTIATION, PROVIDING INSIGHT INTO PHENOTYPES OF PATIENTS WITH APDS. 2021 3 3373 34 HISTONE MODULATION BLOCKS TREG-INDUCED FOXP3 BINDING TO THE IL-2 PROMOTER OF VIRUS-SPECIFIC CD8(+) T CELLS FROM FELINE IMMUNODEFICIENCY VIRUS-INFECTED CATS. CD8(+) T CELLS ARE CRITICAL FOR CONTROLLING HIV INFECTION. DURING THE CHRONIC PHASE OF LENTIVIRAL INFECTION, CD8(+) T CELLS LOSE THEIR PROLIFERATIVE CAPACITY AND EXHIBIT IMPAIRED ANTIVIRAL FUNCTION. THIS LOSS OF CD8(+) T CELL FUNCTION IS DUE, IN PART, TO CD4(+)CD25(+) T REGULATORY (TREG) CELL-MEDIATED SUPPRESSION. OUR RESEARCH GROUP HAS DEMONSTRATED THAT LENTIVIRUS-ACTIVATED CD4(+)CD25(+) TREG CELLS INDUCE THE REPRESSIVE TRANSCRIPTION FACTOR FORKHEAD BOX P3 (FOXP3) IN AUTOLOGOUS CD8(+) T CELLS FOLLOWING CO-CULTURE. WE HAVE RECENTLY REPORTED THAT TREG-INDUCED FOXP3 BINDS THE INTERLEUKIN-2 (IL-2), INTERFERON-GAMMA (IFN- GAMMA), AND TUMOR NECROSIS FACTOR-ALPHA (TNF-ALPHA) PROMOTERS IN VIRUS-SPECIFIC CD8(+) T CELLS. THESE DATA SUGGEST AN IMPORTANT ROLE OF FOXP3-MEDIATED CD8(+) T CELL DYSFUNCTION IN LENTIVIRAL INFECTION. TO ELUCIDATE THE MECHANISM OF THIS SUPPRESSION, WE PREVIOUSLY REPORTED THAT DECREASED METHYLATION FACILITATES FOXP3 BINDING IN MITOGEN-ACTIVATED CD8(+) T CELLS FROM FELINE IMMUNODEFICIENCY VIRUS (FIV)-INFECTED CATS. WE DEMONSTRATED THE REDUCED BINDING OF FOXP3 TO THE IL-2 PROMOTER BY INCREASING METHYLATION OF CD8(+) T CELLS. IN THE STUDIES PRESENTED HERE, WE ASK IF ANOTHER FORM OF EPIGENETIC MODULATION MIGHT ALLEVIATE FOXP3-MEDIATED SUPPRESSION IN CD8(+) T CELLS. WE HYPOTHESIZED THAT DECREASING HISTONE ACETYLATION IN VIRUS-SPECIFIC CD8(+) T CELLS WOULD DECREASE TREG-INDUCED FOXP3 BINDING TO THE IL-2 PROMOTER. INDEED, USING ANACARDIC ACID (AA), A KNOWN HISTONE ACETYL TRANSFERASE (HAT) INHIBITOR, WE DEMONSTRATE A REDUCTION IN FOXP3 BINDING TO THE IL-2 PROMOTER IN VIRUS-SPECIFIC CD8(+) T CELLS CO-CULTURED WITH AUTOLOGOUS TREG CELLS. THESE DATA IDENTIFY A NOVEL MECHANISM OF FOXP3-MEDIATED CD8(+) T CELL DYSFUNCTION DURING LENTIVIRAL INFECTION. 2018 4 2143 38 EPIGENETIC LANDSCAPE OF HIV-1 INFECTION IN PRIMARY HUMAN MACROPHAGE. HUMAN IMMUNODEFICIENCY VIRUS (HIV)-INFECTED MACROPHAGES ARE LONG-LIVED CELLS THAT SUSTAIN PERSISTENT VIRUS EXPRESSION, WHICH IS BOTH A BARRIER TO VIRAL ERADICATION AND CONTRIBUTOR TO NEUROLOGICAL COMPLICATIONS IN PATIENTS DESPITE ANTIRETROVIRAL THERAPY (ART). TO BETTER UNDERSTAND THE REGULATION OF HIV-1 IN MACROPHAGES, WE COMPARED HIV-INFECTED PRIMARY HUMAN MONOCYTE-DERIVED MACROPHAGES (MDM) TO ACUTELY INFECTED PRIMARY CD4 T CELLS AND JURKAT CELLS LATENTLY INFECTED WITH HIV (JLAT 8.4). HIV GENOMES IN MDM WERE ACTIVELY TRANSCRIBED DESPITE ENRICHMENT WITH HETEROCHROMATIN-ASSOCIATED H3K9ME3 ACROSS THE COMPLETE HIV GENOME IN COMBINATION WITH ELEVATED ACTIVATION MARKS OF H3K9AC AND H3K27AC AT THE LONG TERMINAL REPEAT (LTR). MACROPHAGE PATTERNS CONTRASTED WITH JLAT CELLS, WHICH SHOWED CONVENTIONAL BIVALENT H3K4ME3/H3K27ME3, AND ACUTELY INFECTED CD4 T CELLS, WHICH SHOWED AN INTERMEDIATE EPIGENOTYPE. 5'-METHYLCYTOSINE (5MC) WAS ENRICHED ACROSS THE HIV GENOME IN LATENTLY INFECTED JLAT CELLS, WHILE 5'-HYDROXYMETHYLCYTOSINE (5HMC) WAS ENRICHED IN CD4 CELLS AND MDMS. HIV INFECTION INDUCED MULTINUCLEATION OF MDMS ALONG WITH DNA DAMAGE-ASSOCIATED P53 PHOSPHORYLATION, AS WELL AS LOSS OF TET2 AND THE NUCLEAR REDISTRIBUTION OF 5-HYDOXYMETHYLATION. TAKEN TOGETHER, OUR FINDINGS SUGGEST THAT HIV INDUCES A UNIQUE MACROPHAGE NUCLEAR AND TRANSCRIPTIONAL PROFILE, AND VIRAL GENOMES ARE MAINTAINED IN A NONCANONICAL BIVALENT EPIGENETIC STATE. IMPORTANCE MACROPHAGES SERVE AS A RESERVOIR FOR LONG-TERM PERSISTENCE AND CHRONIC PRODUCTION OF HIV. WE FOUND AN ATYPICAL EPIGENETIC CONTROL OF HIV IN MACROPHAGES MARKED BY HETEROCHROMATIC H3K9ME3 DESPITE ACTIVE VIRAL TRANSCRIPTION. HIV INFECTION INDUCED CHANGES IN MACROPHAGE NUCLEAR MORPHOLOGY AND EPIGENETIC REGULATORY FACTORS. THESE FINDINGS MAY IDENTIFY NEW MECHANISMS TO CONTROL CHRONIC HIV EXPRESSION IN INFECTED MACROPHAGES. 2022 5 2392 35 EPIGENETIC REPRESSION OF INTERLEUKIN 2 EXPRESSION IN SENESCENT CD4+ T CELLS DURING CHRONIC HIV TYPE 1 INFECTION. THE MOLECULAR MECHANISMS FOR IL2 GENE-SPECIFIC DYSREGULATION DURING CHRONIC HUMAN IMMUNODEFICIENCY VIRUS TYPE 1 (HIV-1) INFECTION ARE UNKNOWN. HERE, WE INVESTIGATED THE ROLE OF DNA METHYLATION IN SUPPRESSING INTERLEUKIN 2 (IL-2) EXPRESSION IN MEMORY CD4(+) T CELLS DURING CHRONIC HIV-1 INFECTION. WE OBSERVED THAT CPG SITES IN THE IL2 PROMOTER OF CD4(+) T CELLS WERE FULLY METHYLATED IN NAIVE CD4(+) T CELLS AND SIGNIFICANTLY DEMETHYLATED IN THE MEMORY POPULATIONS. INTERESTINGLY, WE FOUND THAT THE MEMORY CELLS THAT HAD A TERMINALLY DIFFERENTIATED PHENOTYPE AND EXPRESSED CD57 HAD INCREASED IL2 PROMOTER METHYLATION RELATIVE TO LESS DIFFERENTIATED MEMORY CELLS IN HEALTHY INDIVIDUALS. IMPORTANTLY, EARLY EFFECTOR MEMORY SUBSETS FROM HIV-1-INFECTED SUBJECTS EXPRESSED HIGH LEVELS OF CD57 AND WERE HIGHLY METHYLATED AT THE IL2 LOCUS. FURTHERMORE, THE INCREASED CD57 EXPRESSION ON MEMORY CD4(+) T CELLS WAS INVERSELY CORRELATED WITH IL-2 PRODUCTION. THESE DATA SUGGEST THAT DNA METHYLATION AT THE IL2 LOCUS IN CD4(+) T CELLS IS COUPLED TO IMMUNOSENESCENCE AND PLAYS A CRITICAL ROLE IN THE BROAD DYSFUNCTION THAT OCCURS IN POLYCLONAL T CELLS DURING HIV-1 INFECTION. 2015 6 2421 28 EPIGENETIC SIGNATURE OF PD-1+ TCF1+ CD8 T CELLS THAT ACT AS RESOURCE CELLS DURING CHRONIC VIRAL INFECTION AND RESPOND TO PD-1 BLOCKADE. WE HAVE RECENTLY DEFINED A NOVEL POPULATION OF PD-1 (PROGRAMMED CELL DEATH 1)+ TCF1 (T CELL FACTOR 1)+ VIRUS-SPECIFIC CD8 T CELLS THAT FUNCTION AS RESOURCE CELLS DURING CHRONIC LCMV INFECTION AND PROVIDE THE PROLIFERATIVE BURST SEEN AFTER PD-1 BLOCKADE. SUCH CD8 T CELLS HAVE BEEN FOUND IN OTHER CHRONIC INFECTIONS AND ALSO IN CANCER IN MICE AND HUMANS. THESE CD8 T CELLS EXHIBIT STEM-LIKE PROPERTIES UNDERGOING SELF-RENEWAL AND ALSO DIFFERENTIATING INTO THE TERMINALLY EXHAUSTED CD8 T CELLS. HERE WE COMPARED THE EPIGENETIC SIGNATURE OF STEM-LIKE CD8 T CELLS WITH EXHAUSTED CD8 T CELLS. ATAC-SEQ ANALYSIS SHOWED THAT STEM-LIKE CD8 T CELLS HAD A UNIQUE SIGNATURE IMPLICATING ACTIVITY OF HMG (TCF) AND RHD (NF-KAPPAB) TRANSCRIPTION FACTOR FAMILY MEMBERS IN CONTRAST TO HIGHER ACCESSIBILITY TO ETS AND RUNX MOTIFS IN EXHAUSTED CD8 T CELLS. IN ADDITION, REGULATORY REGIONS OF THE TRANSCRIPTION FACTORS TCF7 AND ID3 WERE MORE ACCESSIBLE IN STEM-LIKE CELLS WHEREAS PRDM1 AND ID2 WERE MORE ACCESSIBLE IN EXHAUSTED CD8 T CELLS. WE ALSO COMPARED THE EPIGENETIC SIGNATURES OF THE 2 CD8 T CELL SUBSETS FROM CHRONICALLY INFECTED MICE WITH EFFECTOR AND MEMORY CD8 T CELLS GENERATED AFTER AN ACUTE LCMV INFECTION. BOTH CD8 T CELL SUBSETS GENERATED DURING CHRONIC INFECTION WERE STRIKINGLY DIFFERENT FROM CD8 T CELL SUBSETS FROM ACUTE INFECTION. INTERESTINGLY, THE STEM-LIKE CD8 T CELL SUBSET FROM CHRONIC INFECTION, DESPITE SHARING KEY FUNCTIONAL PROPERTIES WITH MEMORY CD8 T CELLS, HAD A VERY DISTINCT EPIGENETIC PROGRAM. THESE RESULTS SHOW THAT THE CHRONIC STEM-LIKE CD8 T CELL PROGRAM REPRESENTS A SPECIFIC ADAPTATION OF THE T CELL RESPONSE TO PERSISTENT ANTIGENIC STIMULATION. 2019 7 5897 29 T FOLLICULAR HELPER CELL-DEPENDENT CLEARANCE OF A PERSISTENT VIRUS INFECTION REQUIRES T CELL EXPRESSION OF THE HISTONE DEMETHYLASE UTX. EPIGENETIC CHANGES, INCLUDING HISTONE METHYLATION, CONTROL T CELL DIFFERENTIATION AND MEMORY FORMATION, THOUGH THE ENZYMES THAT MEDIATE THESE PROCESSES ARE NOT CLEAR. WE SHOW THAT UTX, A HISTONE H3 LYSINE 27 (H3K27) DEMETHYLASE, SUPPORTS T FOLLICULAR HELPER (TFH) CELL RESPONSES THAT ARE ESSENTIAL FOR B CELL ANTIBODY GENERATION AND THE RESOLUTION OF CHRONIC VIRAL INFECTIONS. MICE WITH A T CELL-SPECIFIC UTX DELETION HAD FEWER TFH CELLS, REDUCED GERMINAL CENTER RESPONSES, LACKED VIRUS-SPECIFIC IMMUNOGLOBULIN G (IGG), AND WERE UNABLE TO RESOLVE CHRONIC LYMPHOCYTIC CHORIOMENINGITIS VIRUS INFECTIONS. UTX-DEFICIENT T CELLS SHOWED DECREASED EXPRESSION OF INTERLEUKIN-6 RECEPTOR-ALPHA AND OTHER TFH CELL-RELATED GENES THAT WERE ASSOCIATED WITH INCREASED H3K27 METHYLATION. ADDITIONALLY, TURNER SYNDROME SUBJECTS, WHO ARE PREDISPOSED TO CHRONIC EAR INFECTIONS, HAD REDUCED UTX EXPRESSION IN IMMUNE CELLS AND DECREASED CIRCULATING CD4(+) CXCR5(+) T CELL FREQUENCY. THUS, WE IDENTIFY A CRITICAL LINK BETWEEN UTX IN T CELLS AND IMMUNITY TO INFECTION. 2015 8 6481 33 TOX IS EXPRESSED BY EXHAUSTED AND POLYFUNCTIONAL HUMAN EFFECTOR MEMORY CD8(+) T CELLS. CD8(+) T CELL EXHAUSTION IS A HALLMARK OF MANY CANCERS AND CHRONIC INFECTIONS. IN MICE, T CELL FACTOR 1 (TCF-1) MAINTAINS EXHAUSTED CD8(+) T CELL RESPONSES, WHEREAS THYMOCYTE SELECTION-ASSOCIATED HMG BOX (TOX) IS REQUIRED FOR THE EPIGENETIC REMODELING AND SURVIVAL OF EXHAUSTED CD8(+) T CELLS. HOWEVER, IT HAS REMAINED UNCLEAR TO WHAT EXTENT THESE TRANSCRIPTION FACTORS PLAY ANALOGOUS ROLES IN HUMANS. IN THIS STUDY, WE MAPPED THE EXPRESSION OF TOX AND TCF-1 AS A FUNCTION OF DIFFERENTIATION AND SPECIFICITY IN THE HUMAN CD8(+) T CELL LANDSCAPE. HERE, WE DEMONSTRATE THAT CIRCULATING TOX(+) CD8(+) T CELLS EXIST IN MOST HUMANS, BUT THAT TOX IS NOT EXCLUSIVELY ASSOCIATED WITH EXHAUSTION. EFFECTOR MEMORY CD8(+) T CELLS GENERALLY EXPRESSED TOX, WHEREAS NAIVE AND EARLY-DIFFERENTIATED MEMORY CD8(+) T CELLS GENERALLY EXPRESSED TCF-1. CYTOLYTIC GENE AND PROTEIN EXPRESSION SIGNATURES WERE ALSO DEFINED BY THE EXPRESSION OF TOX. IN THE CONTEXT OF A RELENTLESS IMMUNE CHALLENGE, EXHAUSTED HIV-SPECIFIC CD8(+) T CELLS COMMONLY EXPRESSED TOX, OFTEN IN CLUSTERS WITH VARIOUS ACTIVATION MARKERS AND INHIBITORY RECEPTORS, AND EXPRESSED LESS TCF-1. HOWEVER, POLYFUNCTIONAL MEMORY CD8(+) T CELLS SPECIFIC FOR CYTOMEGALOVIRUS (CMV) OR EPSTEIN-BARR VIRUS (EBV) ALSO EXPRESSED TOX, EITHER WITH OR WITHOUT TCF-1. A SIMILAR PHENOTYPE WAS OBSERVED AMONG HIV-SPECIFIC CD8(+) T CELLS FROM INDIVIDUALS WHO MAINTAINED EXCEPTIONAL IMMUNE CONTROL OF VIRAL REPLICATION. COLLECTIVELY, THESE DATA DEMONSTRATE THAT TOX IS EXPRESSED BY MOST CIRCULATING EFFECTOR MEMORY CD8(+) T CELL SUBSETS AND NOT EXCLUSIVELY LINKED TO EXHAUSTION. 2020 9 5066 41 PHTHALATES SUPPRESS TYPE I INTERFERON IN HUMAN PLASMACYTOID DENDRITIC CELLS VIA EPIGENETIC REGULATION. BACKGROUND: EXPOSURE TO ENVIRONMENTAL ENDOCRINE-DISRUPTING CHEMICALS (EDCS) IS ASSOCIATED WITH ALLERGY, CHRONIC INFLAMMATION, AND IMMUNODEFICIENCY. PHTHALATES, THE COMMON EDCS USED IN PLASTIC INDUSTRY, MAY ACT AS ADJUVANTS TO DISRUPT IMMUNE SYSTEM AND ENHANCE ALLERGY. PLASMACYTOID DCS (PDCS) ARE PREDOMINANT CELLS SECRETING TYPE I INTERFERON (IFN) AGAINST INFECTION AND ARE PROFESSIONAL ANTIGEN-PRESENTING CELLS IN REGULATING ADAPTIVE IMMUNITY. HOWEVER, THE EFFECTS OF PHTHALATES ON THE FUNCTION OF PDCS ARE UNKNOWN. METHODS: CIRCULATING PDCS WERE ISOLATED FROM HEALTHY SUBJECTS, WERE PRETREATED WITH DIETHYLHEXYL PHTHALATE (DEHP) AND BUTYL BENZYL PHTHALATE (BBP), AND WERE STIMULATED WITH TOLL-LIKE RECEPTOR (TLR)-9 AGONIST CPG. IFN-ALPHA/IFN-BETA LEVELS, SURFACE MARKERS, AND T-CELL STIMULATORY FUNCTION WERE INVESTIGATED USING ELISA, FLOW CYTOMETRY, AND PDC/T-CELL COCULTURE ASSAY. MECHANISMS WERE INVESTIGATED USING RECEPTOR ANTAGONISTS, PATHWAY INHIBITORS, WESTERN BLOTTING, AND CHROMATIN IMMUNOPRECIPITATION. RESULTS: DIETHYLHEXYL PHTHALATE AND BUTYL BENZYL PHTHALATE SUPPRESSED CPG-INDUCED IFN-ALPHA/IFN-BETA EXPRESSION IN PDCS, AND THE EFFECT WAS REVERSED BY ARYL HYDROCARBON RECEPTOR (AHR) ANTAGONIST. DIETHYLHEXYL PHTHALATE SUPPRESSED CPG-ACTIVATED MITOGEN-ACTIVATED PROTEIN KINASE (MAPK)-MEK1/2-ERK-ELK1 AND NFKAPPAB SIGNALING PATHWAYS. DIETHYLHEXYL PHTHALATE SUPPRESSED CPG-INDUCED INTERFERON REGULATORY FACTOR (IRF)-7 EXPRESSION BY SUPPRESSING HISTONE H3K4 TRIMETHYLATION AT IRF7 GENE PROMOTER REGION THROUGH INHIBITING TRANSLOCATION OF H3K4-SPECIFIC TRIMETHYLTRANSFERASE WDR5 FROM CYTOPLASM INTO NUCLEUS. BUTYL BENZYL PHTHALATE OR DIETHYLHEXYL PHTHALATE-TREATED PDCS SUPPRESSED IFN-GAMMA BUT ENHANCED IL-13 PRODUCTION BY CD4+ T CELLS. CONCLUSION: PHTHALATES MAY INTERFERE WITH IMMUNITY AGAINST INFECTION AND PROMOTE THE DEVIATION OF TH2 RESPONSE TO INCREASE ALLERGY BY ACTING ON HUMAN PDCS VIA SUPPRESSING IFN-ALPHA/IFN-BETA EXPRESSION AND MODULATING THE ABILITY TO STIMULATE T-CELL RESPONSES. 2013 10 5902 40 T-HELPER 17 CELL POLARIZATION IN PULMONARY ARTERIAL HYPERTENSION. BACKGROUND: INFLAMMATION MAY CONTRIBUTE TO THE PATHOBIOLOGY OF PULMONARY ARTERIAL HYPERTENSION (PAH). DECIPHERING THE PAH FINGERPRINT ON THE INFLAMMATION ORCHESTRATED BY DENDRITIC CELLS (DCS) AND T CELLS, KEY DRIVER AND EFFECTOR CELLS, RESPECTIVELY, OF THE IMMUNE SYSTEM, MAY ALLOW THE IDENTIFICATION OF IMMUNOPATHOLOGIC APPROACHES TO PAH MANAGEMENT. METHODS: USING FLOW CYTOMETRY, WE PERFORMED IMMUNOPHENOTYPING OF MONOCYTE-DERIVED DCS (MODCS) AND CIRCULATING LYMPHOCYTES FROM PATIENTS WITH IDIOPATHIC PAH AND CONTROL SUBJECTS. WITH THE SAME TECHNIQUE, WE PERFORMED CYTOKINE PROFILING OF BOTH POPULATIONS FOLLOWING STIMULATION, COCULTURE, OR BOTH. WE TESTED THE IMMUNOMODULATORY EFFECTS OF A GLUCOCORTICOID (DEXAMETHASONE [DEX]) ON THIS IMMUNOPHENOTYPE AND CYTOKINE PROFILE. USING AN EPIGENETIC APPROACH, WE CONFIRMED THE IMMUNE POLARIZATION IN BLOOD DNA OF PATIENTS WITH PAH. RESULTS: THE PROFILE OF MEMBRANE COSTIMULATORY MOLECULES OF PAH MODCS WAS SIMILAR TO THAT OF CONTROL SUBJECTS. HOWEVER, PAH MODCS RETAINED HIGHER LEVELS OF THE T-CELL ACTIVATING MOLECULES CD86 AND CD40 AFTER DEX PRETREATMENT THAN DID CONTROL MODCS. THIS WAS ASSOCIATED WITH AN INCREASED EXPRESSION OF IL-12P40 AND A REDUCED MIGRATION TOWARD CHEMOKINE (C-C MOTIF) LIGAND 21. MOREOVER, BOTH WITH AND WITHOUT DEX, PAH MODCS INDUCED A HIGHER ACTIVATION AND PROLIFERATION OF CD4+ T CELLS, ASSOCIATED WITH A REDUCED EXPRESSION OF IL-4 (T HELPER 2 RESPONSE) AND A HIGHER EXPRESSION OF IL-17 (T HELPER 17 RESPONSE). PURIFIED PAH CD4+ T CELLS EXPRESSED A HIGHER LEVEL OF IL-17 AFTER ACTIVATION THAN DID THOSE OF CONTROL SUBJECTS. LASTLY, THERE WAS SIGNIFICANT HYPOMETHYLATION OF THE IL-17 PROMOTER IN THE PAH BLOOD DNA AS COMPARED WITH THE CONTROL BLOOD. CONCLUSIONS: WE HAVE HIGHLIGHTED T HELPER 17 CELL IMMUNE POLARIZATION IN PATIENTS WITH PAH, AS HAS BEEN PREVIOUSLY DEMONSTRATED IN OTHER CHRONIC INFLAMMATORY AND AUTOIMMUNE CONDITIONS. 2015 11 1472 33 DISTINCT MECHANISMS REGULATE IL1B GENE TRANSCRIPTION IN LYMPHOID CD4 T CELLS AND MONOCYTES. INTERLEUKIN 1BETA IS A PRO-INFLAMMATORY CYTOKINE IMPORTANT FOR BOTH NORMAL IMMUNE RESPONSES AND CHRONIC INFLAMMATORY DISEASES. THE REGULATION OF THE 31 KDA PROIL-1BETA PRECURSOR CODED BY THE IL1B GENE HAS BEEN EXTENSIVELY STUDIED IN MYELOID CELLS, BUT NOT IN LYMPHOID-DERIVED CD4 T CELLS. SURPRISINGLY, WE FOUND THAT SOME CD4 T CELL SUBSETS EXPRESS HIGHER LEVELS OF PROIL-1BETA THAN UNSTIMULATED MONOCYTES, DESPITE RELATIVELY LOW IL1B MRNA LEVELS. WE OBSERVED A SIGNIFICANT INCREASE IN IL1B TRANSCRIPTION AND TRANSLATION IN CD4 T CELLS UPON EX VIVO CD3/CD28 ACTIVATION, AND A SIMILAR ELEVATION IN THE CCR5+ EFFECTOR MEMORY POPULATION COMPARED TO CCR5- T CELLS IN VIVO. THE RAPID AND VIGOROUS INCREASE IN IL1B GENE TRANSCRIPTION FOR STIMULATED MONOCYTES HAS PREVIOUSLY BEEN ASSOCIATED WITH THE PRESENCE OF SPI-1/PU.1 (SPI1), A MYELOID-LINEAGE TRANSCRIPTION FACTOR, PRE-BOUND TO THE PROMOTER. IN THE CASE OF CD4 T CELLS, THIS INCREASE OCCURRED DESPITE THE LACK OF DETECTABLE SPI1 AT THE IL1B PROMOTER. ADDITIONALLY, WE FOUND ALTERED EPIGENETIC REGULATION OF THE IL1B LOCUS IN CD3/CD28-ACTIVATED CD4 T CELLS. UNLIKE MONOCYTES, ACTIVATED CD4 T CELLS POSSESS BIVALENT H3K4ME3+/H3K27ME3+ NUCLEOSOME MARKS AT THE IL1B PROMOTER, REFLECTING LOW TRANSCRIPTIONAL ACTIVITY. THESE RESULTS SUPPORT A MODEL IN WHICH THE IL1B GENE IN CD4 T CELLS IS TRANSCRIBED FROM A LOW-ACTIVITY BIVALENT PROMOTER INDEPENDENT OF SPI1. ACCUMULATED CYTOPLASMIC PROIL-1BETA MAY ULTIMATELY BE CLEAVED TO MATURE 17 KDA BIOACTIVE IL-1BETA, REGULATING T CELL POLARIZATION AND PATHOGENIC CHRONIC INFLAMMATION. 2018 12 1937 30 EOMES IS ESSENTIAL FOR ANTITUMOR ACTIVITY OF CD8(+) T CELLS IN CHRONIC LYMPHOCYTIC LEUKEMIA. GENOME-WIDE ASSOCIATION STUDIES IDENTIFIED A SINGLE-NUCLEOTIDE POLYMORPHISM (SNP) AFFECTING THE TRANSCRIPTION FACTOR EOMESODERMIN (EOMES) ASSOCIATED WITH A SIGNIFICANTLY INCREASED RISK TO DEVELOP CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). EPIGENETIC ANALYSES, RNA SEQUENCING, AND FLOW CYTOMETRY REVEALED THAT EOMES IS NOT EXPRESSED IN CLL CELLS, BUT IN CD8(+) T CELLS FOR WHICH EOMES IS A KNOWN MASTER REGULATOR. WE THUS HYPOTHESIZED THAT THE INCREASED CLL RISK ASSOCIATED WITH THE EOMES SNP MIGHT BE EXPLAINED BY ITS NEGATIVE IMPACT ON CD8(+) T-CELL-MEDIATED IMMUNE CONTROL OF CLL. FLOW CYTOMETRY ANALYSES REVEALED A HIGHER EOMES EXPRESSION IN CD8(+) T CELLS OF CLL PATIENTS COMPARED TO HEALTHY INDIVIDUALS, AND AN ACCUMULATION OF PD-1(+) EOMES(+) CD8(+) T CELLS IN LYMPH NODES RATHER THAN BLOOD OR BONE MARROW IN CLL. THIS WAS IN LINE WITH AN OBSERVED EXPANSION OF EOMES(+) CD8(+) T CELLS IN THE SPLEEN OF LEUKEMIC EMICRO-TCL1 MICE. AS EOMES EXPRESSION WAS HIGHEST IN CD8(+) T CELLS THAT EXPRESS INHIBITORY RECEPTORS, AN INVOLVEMENT OF EOMES IN T-CELL EXHAUSTION AND DYSFUNCTION SEEMS LIKELY. INTERESTINGLY, EOMES-DEFICIENCY IN CD8(+) T CELLS RESULTED IN THEIR IMPAIRED EXPANSION ASSOCIATED WITH DECREASED CLL CONTROL IN MICE. OVERALL, THESE OBSERVATIONS SUGGEST THAT EOMES IS ESSENTIAL FOR CD8(+) T-CELL EXPANSION AND/OR MAINTENANCE, AND THEREFORE INVOLVED IN ADAPTIVE IMMUNE CONTROL OF CLL. 2021 13 912 26 CHRONIC EXPOSURE TO WATER POLLUTANT TRICHLOROETHYLENE INCREASED EPIGENETIC DRIFT IN CD4(+) T CELLS. AIM: AUTOIMMUNE DISEASE AND CD4(+) T-CELL ALTERATIONS ARE INDUCED IN MICE EXPOSED TO THE WATER POLLUTANT TRICHLOROETHYLENE (TCE). WE EXAMINED HERE WHETHER TCE ALTERED GENE-SPECIFIC DNA METHYLATION IN CD4(+) T CELLS AS A POSSIBLE MECHANISM OF IMMUNOTOXICITY. MATERIALS & METHODS: NAIVE AND EFFECTOR/MEMORY CD4(+) T CELLS FROM MICE EXPOSED TO TCE (0.5 MG/ML IN DRINKING WATER) FOR 40 WEEKS WERE EXAMINED BY BISULFITE NEXT-GENERATION DNA SEQUENCING. RESULTS: A PROBABILISTIC MODEL CALCULATED FROM MULTIPLE GENES SHOWED THAT TCE DECREASED METHYLATION CONTROL IN CD4(+) T CELLS. DATA FROM INDIVIDUAL GENES FITTED TO A QUADRATIC REGRESSION MODEL SHOWED THAT TCE INCREASED GENE-SPECIFIC METHYLATION VARIANCE IN BOTH CD4 SUBSETS. CONCLUSION: TCE INCREASED EPIGENETIC DRIFT OF SPECIFIC CPG SITES IN CD4(+) T CELLS. 2016 14 6519 29 TRANSCRIPTIONAL AND EPIGENETIC REGULATION OF INTERLEUKIN-2 GENE IN ACTIVATED T CELLS BY MORPHINE. CHRONIC MORPHINE INHIBITS INTERLEUKIN-2 (IL-2) AT BOTH THE TRANSCRIPTIONAL AND PROTEIN SYNTHESIS LEVELS. THE MOLECULAR MECHANISMS BY WHICH MORPHINE DECREASES IL-2 ARE NOT FULLY UNDERSTOOD. THE PRODUCTION OF IL-2 IS TIGHTLY REGULATED BY SEVERAL TRANSCRIPTION FACTORS THAT BIND TO THE IL-2 PROMOTER. HEREIN, WE SHOW THAT CHRONIC MORPHINE TREATMENT RESULTS IN AN INCREASE IN CAMP LEVELS WITH A CONCURRENT UP-REGULATION OF THE CAMP INDUCIBLE REPRESSOR INDUCIBLE CAMP EARLY REPRESSOR (ICER)/CAMP RESPONSE ELEMENT MODULATOR (CREM) AND DOWN-REGULATION OF P-CAMP-RESPONSE ELEMENT-BINDING PROTEIN (CREB) IN ACTIVATED T CELLS. FURTHERMORE, ICER COMPETES FOR P-CREB BINDING TO THE CAMP-RESPONSIVE ELEMENTS (CRES) SITE. THIS LEADS TO THE UNCOUPLING OF CBP/P300 THEREBY ABROGATING IL-2 TRANSCRIPTION. OVEREXPRESSION OF EITHER ANTISENSE CREM OR CREB PLASMID RESCUED MORPHINE-INDUCED INHIBITION OF IL-2 PROMOTER ACTIVITY AND PROTEIN PRODUCTION. IN ADDITION, WE ALSO FOUND THAT CHRONIC MORPHINE TREATMENT INHIBITED THE ACETYLATION AND TRIMETHYLATION OF HISTONES AND DECREASED BOTH DNA DEMETHYLATION AND ACCESSIBILITY OF THE IL-2 PROMOTER. THESE FINDINGS SUGGEST THAT CHRONIC MORPHINE TREATMENT MAY FUNCTION THROUGH BOTH TRANSCRIPTIONAL AND EPIGENETIC MECHANISMS TO INHIBIT IL-2 PRODUCTION. 2007 15 559 22 BACH2 ENFORCES THE TRANSCRIPTIONAL AND EPIGENETIC PROGRAMS OF STEM-LIKE CD8(+) T CELLS. DURING CHRONIC INFECTION AND CANCER, A SELF-RENEWING CD8(+) T CELL SUBSET MAINTAINS LONG-TERM IMMUNITY AND IS CRITICAL TO THE EFFECTIVENESS OF IMMUNOTHERAPY. THESE STEM-LIKE CD8(+) T CELLS DIVERGE FROM OTHER CD8(+) SUBSETS EARLY AFTER CHRONIC VIRAL INFECTION. HOWEVER, PATHWAYS GUARDING STEM-LIKE CD8(+) T CELLS AGAINST TERMINAL EXHAUSTION REMAIN UNCLEAR. HERE, WE SHOW THAT THE GENE ENCODING TRANSCRIPTIONAL REPRESSOR BACH2 IS TRANSCRIPTIONALLY AND EPIGENETICALLY ACTIVE IN STEM-LIKE CD8(+) T CELLS BUT NOT TERMINALLY EXHAUSTED CELLS EARLY AFTER INFECTION. BACH2 OVEREXPRESSION ENFORCED STEM-LIKE CELL FATE, WHEREAS BACH2 DEFICIENCY IMPAIRED STEM-LIKE CD8(+) T CELL DIFFERENTIATION. SINGLE-CELL TRANSCRIPTOMIC AND EPIGENOMIC APPROACHES REVEALED THAT BACH2 ESTABLISHED THE TRANSCRIPTIONAL AND EPIGENETIC PROGRAMS OF STEM-LIKE CD8(+) T CELLS. IN ADDITION, BACH2 SUPPRESSED THE MOLECULAR PROGRAM DRIVING TERMINAL EXHAUSTION THROUGH TRANSCRIPTIONAL REPRESSION AND EPIGENETIC SILENCING. THUS, OUR STUDY REVEALS A NEW PATHWAY THAT ENFORCES COMMITMENT TO STEM-LIKE CD8(+) LINEAGE AND PREVENTS AN ALTERNATIVE TERMINALLY EXHAUSTED CELL FATE. 2021 16 205 27 ACTIVATION OF HLA-G EXPRESSION BY 5-AZA-2 - DEOXYCYTIDINE IN MALIGNANT HEMATOPOETIC CELLS ISOLATED FROM LEUKEMIA PATIENTS. HUMAN LEUKOCYTE ANTIGEN - G (HLA-G) IS A NON-CLASSICAL HLA CLASS I ANTIGEN WITH RESTRICTED DISTRIBUTION IN NORMAL TISSUES. ECTOPIC HLA-G EXPRESSION OBSERVED AT SOME PATHOLOGICAL CIRCUMSTANCES AS MALIGNANT TRANSFORMATION MIGHT BE TRIGGERED BY EPIGENETIC MODIFICATIONS SUCH AS DNA DEMETHYLATION. RECENTLY IT WAS DEMONSTRATED THAT DNA METHYLTRANSFERASE INHIBITOR 5-AZA-2 - DEOXYCYTIDINE (ADC) INDUCES/ENHANCES HLA-G TRANSCRIPTION IN MANY LEUKEMIA CELL LINES OF DIFFERENT ORIGIN. HERE WE INVESTIGATED THE EFFECT OF ADC ON HLA-G EXPRESSION IN MALIGNANT HEMATOPOETIC CELLS ISOLATED FROM PATIENTS WITH ACUTE MYELOID LEUKEMIA (AML) AND CHRONIC LYMPHOCYTIC LEUKEMIA (B-CLL). WE DETECTED HLA-G EXPRESSION IN UNTREATED CELLS FROM SOME PATIENTS. NEVERTHELESS TREATMENT WITH 5-AZA-2 - DEOXYCYTIDINE ENHANCED HLA-G TRANSCRIPTION AND CONCOMITANTLY HLA-G PROTEIN SYNTHESIS IN SOME LEUKEMIA CELLS. 2009 17 1759 30 EARLY PRECURSOR T CELLS ESTABLISH AND PROPAGATE T CELL EXHAUSTION IN CHRONIC INFECTION. CD8(+) T CELLS RESPONDING TO CHRONIC INFECTIONS OR TUMORS ACQUIRE AN 'EXHAUSTED' STATE ASSOCIATED WITH ELEVATED EXPRESSION OF INHIBITORY RECEPTORS, INCLUDING PD-1, AND IMPAIRED CYTOKINE PRODUCTION. EXHAUSTED T CELLS ARE CONTINUOUSLY REPLENISHED BY T CELLS WITH PRECURSOR CHARACTERISTICS THAT SELF-RENEW AND DEPEND ON THE TRANSCRIPTION FACTOR TCF1; HOWEVER, THEIR DEVELOPMENTAL REQUIREMENTS ARE POORLY UNDERSTOOD. IN THE PRESENT STUDY, WE DEMONSTRATE THAT HIGH ANTIGEN LOAD PROMOTED THE DIFFERENTIATION OF PRECURSOR T CELLS, WHICH ACQUIRED HALLMARKS OF EXHAUSTION WITHIN DAYS OF INFECTION, WHEREAS EARLY EFFECTOR CELLS RETAINED POLYFUNCTIONAL FEATURES. EARLY PRECURSOR T CELLS SHOWED EPIGENETIC IMPRINTING CHARACTERISTIC OF T CELL RECEPTOR-DEPENDENT TRANSCRIPTION FACTOR BINDING AND WERE RESTRICTED TO THE GENERATION OF CELLS DISPLAYING EXHAUSTION CHARACTERISTICS. TRANSCRIPTION FACTORS BACH2 AND BATF WERE KEY REGULATORS WITH OPPOSING FUNCTIONS IN THE GENERATION OF EARLY PRECURSOR T CELLS. OVERALL, WE DEMONSTRATE THAT EXHAUSTION MANIFESTS FIRST IN TCF1(+) PRECURSOR T CELLS AND IS PROPAGATED SUBSEQUENTLY TO THE POOL OF ANTIGEN-SPECIFIC T CELLS. 2020 18 5082 29 PI3KDELTA/GAMMA INHIBITION PROMOTES HUMAN CART CELL EPIGENETIC AND METABOLIC REPROGRAMMING TO ENHANCE ANTITUMOR CYTOTOXICITY. CURRENT LIMITATIONS IN USING CHIMERIC ANTIGEN RECEPTOR T(CART) CELLS TO TREAT PATIENTS WITH HEMATOLOGICAL CANCERS INCLUDE LIMITED EXPANSION AND PERSISTENCE IN VIVO THAT CONTRIBUTE TO CANCER RELAPSE. PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) HAVE TERMINALLY DIFFERENTIATED T CELLS WITH AN EXHAUSTED PHENOTYPE AND EXPERIENCE LOW COMPLETE RESPONSE RATES AFTER AUTOLOGOUS CART THERAPY. BECAUSE PI3K INHIBITOR THERAPY IS ASSOCIATED WITH THE DEVELOPMENT OF T-CELL-MEDIATED AUTOIMMUNITY, WE STUDIED THE EFFECTS OF INHIBITING THE PI3KDELTA AND PI3KGAMMA ISOFORMS DURING THE MANUFACTURE OF CART CELLS PREPARED FROM PATIENTS WITH CLL. DUAL PI3KDELTA/GAMMA INHIBITION NORMALIZED CD4/CD8 RATIOS AND MAXIMIZED THE NUMBER OF CD8+ T-STEM CELL MEMORY, NAIVE, AND CENTRAL MEMORY T-CELLS WITH DOSE-DEPENDENT DECREASES IN EXPRESSION OF THE TIM-3 EXHAUSTION MARKER. CART CELLS MANUFACTURED WITH DUVELISIB (DUV-CART CELLS) SHOWED SIGNIFICANTLY INCREASED IN VITRO CYTOTOXICITY AGAINST CD19+ CLL TARGETS CAUSED BY INCREASED FREQUENCIES OF CD8+ CART CELLS. DUV-CART CELLS HAD INCREASED EXPRESSION OF THE MITOCHONDRIAL FUSION PROTEIN MFN2, WITH AN ASSOCIATED INCREASE IN THE RELATIVE CONTENT OF MITOCHONDRIA. DUV-CART CELLS EXHIBITED INCREASED SIRT1 AND TCF1/7 EXPRESSION, WHICH CORRELATED WITH EPIGENETIC REPROGRAMING OF DUV-CART CELLS TOWARD STEM-LIKE PROPERTIES. AFTER TRANSFER TO NOG MICE ENGRAFTED WITH A HUMAN CLL CELL LINE, DUV-CART CELLS EXPRESSING EITHER A CD28 OR 41BB COSTIMULATORY DOMAIN DEMONSTRATED SIGNIFICANTLY INCREASED IN VIVO EXPANSION OF CD8+ CART CELLS, FASTER ELIMINATION OF CLL, AND LONGER PERSISTENCE. DUV-CART CELLS SIGNIFICANTLY ENHANCED SURVIVAL OF CLL-BEARING MICE COMPARED WITH CONVENTIONALLY MANUFACTURED CART CELLS. IN SUMMARY, EXPOSURE OF CART TO A PI3KDELTA/GAMMA INHIBITOR DURING MANUFACTURING ENRICHED THE CART PRODUCT FOR CD8+ CART CELLS WITH STEM-LIKE QUALITIES AND ENHANCED EFFICACY IN ELIMINATING CLL IN VIVO. 2022 19 5223 34 PRIMARY MURINE CD4+ T CELLS FAIL TO ACQUIRE THE ABILITY TO PRODUCE EFFECTOR CYTOKINES WHEN ACTIVE RAS IS PRESENT DURING TH1/TH2 DIFFERENTIATION. CONSTITUTIVE RAS SIGNALING HAS BEEN SHOWN TO AUGMENT IL-2 PRODUCTION, REVERSE ANERGY, AND FUNCTIONALLY REPLACE MANY ASPECTS OF CD28 CO-STIMULATION IN CD4+ T CELLS. THESE DATA RAISE THE POSSIBILITY THAT INTRODUCTION OF ACTIVE RAS INTO PRIMARY T CELLS MIGHT RESULT IN IMPROVED FUNCTIONALITY IN PATHOLOGIC SITUATIONS OF T CELL DYSFUNCTION, SUCH AS CANCER OR CHRONIC VIRAL INFECTION. TO TEST THE BIOLOGIC EFFECTS OF ACTIVE RAS IN PRIMARY T CELLS, CD4+ T CELLS FROM COXSACKIE-ADENOVIRUS RECEPTOR TRANSGENIC MICE WERE TRANSDUCED WITH AN ADENOVIRUS ENCODING ACTIVE RAS. AS EXPECTED, ACTIVE RAS AUGMENTED IL-2 PRODUCTION IN NAIVE CD4+ T CELLS. HOWEVER, WHEN CELLS WERE CULTURED FOR 4 DAYS UNDER CONDITIONS TO PROMOTE EFFECTOR CELL DIFFERENTIATION, ACTIVE RAS INHIBITED THE ABILITY OF CD4+ T CELLS TO ACQUIRE A TH1 OR TH2 EFFECTOR CYTOKINE PROFILE. THIS DIFFERENTIATION DEFECT WAS NOT DUE TO DEFICIENT STAT4 OR STAT6 ACTIVATION BY IL-12 OR IL-4, RESPECTIVELY, NOR WAS IT ASSOCIATED WITH DEFICIENT INDUCTION OF T-BET AND GATA-3 EXPRESSION. IMPAIRED EFFECTOR CYTOKINE PRODUCTION IN ACTIVE RAS-TRANSDUCED CELLS WAS ASSOCIATED WITH DEFICIENT DEMETHYLATION OF THE IL-4 GENE LOCUS. OUR RESULTS INDICATE THAT, DESPITE AUGMENTING ACUTE ACTIVATION OF NAIVE T CELLS, CONSTITUTIVE RAS SIGNALING INHIBITS THE ABILITY OF CD4+ T CELLS TO PROPERLY DIFFERENTIATE INTO TH1/TH2 EFFECTOR CYTOKINE-PRODUCING CELLS, IN PART BY INTERFERING WITH EPIGENETIC MODIFICATION OF EFFECTOR GENE LOCI. ALTERNATIVE STRATEGIES TO POTENTIATE RAS PATHWAY SIGNALING IN T CELLS IN A MORE REGULATED FASHION SHOULD BE CONSIDERED AS A THERAPEUTIC APPROACH TO IMPROVE IMMUNE RESPONSES IN VIVO. 2014 20 574 32 BCR/ABL INCREASES EZH2 LEVELS WHICH REGULATES XIAP EXPRESSION VIA MIRNA-219 IN CHRONIC MYELOID LEUKEMIA CELLS. IN THIS STUDY, WE SHOWED THAT THE LEVELS OF EZH2 IN BONE MARROW MONONUCLEAR CELLS (BMMNCS) ISOLATED FROM INDIVIDUALS WITH CHRONIC MYELOID LEUKEMIA (CML) (N=12) WERE SIGNIFICANTLY GREATER THAN THOSE IN BMMNCS ISOLATED FROM HEALTHY VOLUNTEERS (N=6) AS WELL AS INDIVIDUALS WITH PHILADELPHIA CHROMOSOME-NEGATIVE MYELOPROLIFERATIVE NEOPLASMS. LENTIVIRAL TRANSDUCTION OF THE BCR/ABL GENE IN BA/F3 CELLS INCREASED EZH2 LEVELS IN PARALLEL WITH PHOSPHORYLATION OF STAT5. NOTABLY, CHROMATIN IMMUNOPRECIPITATION ASSAYS SHOWED THAT STAT5A BOUND TO A PROMOTER REGION OF THE EZH2 GENE, RESULTING IN AN INCREASE IN THE TRANSCRIPTIONAL ACTIVITY OF EZH2 IN LEUKEMIA CELLS. IMPORTANTLY, DOWNREGULATION OF EZH2 BY SHORT HAIRPIN RNAS (SHRNAS) INHIBITED THE EXPRESSION OF XIAP AND INCREASED THE MIR-219 LEVELS ASSOCIATED WITH A DECREASE IN HYPERMETHYLATION OF MIR-219-1 CPG ISLANDS. MOREOVER, OVEREXPRESSION OF MIR-219 DECREASED THE LEVELS OF XIAP IN CML CELLS. SINCE THE 3'-UNTRANSLATED REGION (3'-UTR) OF XIAP CONTAINS MIR219-5P-COMPLEMENTARY BINDING SITE, MIR-219 MIGHT MODULATE THE EXPRESSION OF XIAP THROUGH BINDING OF MIR-219 ON THE 3'-UTR OF XIAP. TAKEN TOGETHER, BCR/ABL POSITIVELY REGULATES THE EXPRESSION OF EZH2 VIA STAT5 SIGNALING. EZH2 MODULATES EPIGENETIC CHANGES AT DNA METHYLATED REGIONS ENCODING MIR-219 AND DOWNREGULATES THE LEVEL OF MIR-219, RESULTING IN UPREGULATION OF XIAP. 2016