1 1759 92 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 2 5223 33 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 3 4386 33 MITOCHONDRIAL STRESS INDUCED BY CONTINUOUS STIMULATION UNDER HYPOXIA RAPIDLY DRIVES T CELL EXHAUSTION. CANCER AND CHRONIC INFECTIONS INDUCE T CELL EXHAUSTION, A HYPOFUNCTIONAL FATE CARRYING DISTINCT EPIGENETIC, TRANSCRIPTOMIC AND METABOLIC CHARACTERISTICS. HOWEVER, DRIVERS OF EXHAUSTION REMAIN POORLY UNDERSTOOD. AS INTRATUMORAL EXHAUSTED T CELLS EXPERIENCE SEVERE HYPOXIA, WE HYPOTHESIZED THAT METABOLIC STRESS ALTERS THEIR RESPONSES TO OTHER SIGNALS, SPECIFICALLY, PERSISTENT ANTIGENIC STIMULATION. IN VITRO, ALTHOUGH CD8(+) T CELLS EXPERIENCING CONTINUOUS STIMULATION OR HYPOXIA ALONE DIFFERENTIATED INTO FUNCTIONAL EFFECTORS, THE COMBINATION RAPIDLY DROVE T CELL DYSFUNCTION CONSISTENT WITH EXHAUSTION. CONTINUOUS STIMULATION PROMOTED BLIMP-1-MEDIATED REPRESSION OF PGC-1ALPHA-DEPENDENT MITOCHONDRIAL REPROGRAMMING, RENDERING CELLS POORLY RESPONSIVE TO HYPOXIA. LOSS OF MITOCHONDRIAL FUNCTION GENERATED INTOLERABLE LEVELS OF REACTIVE OXYGEN SPECIES (ROS), SUFFICIENT TO PROMOTE EXHAUSTED-LIKE STATES, IN PART THROUGH PHOSPHATASE INHIBITION AND THE CONSEQUENT ACTIVITY OF NUCLEAR FACTOR OF ACTIVATED T CELLS. REDUCING T CELL-INTRINSIC ROS AND LOWERING TUMOR HYPOXIA LIMITED T CELL EXHAUSTION, SYNERGIZING WITH IMMUNOTHERAPY. THUS, IMMUNOLOGIC AND METABOLIC SIGNALING ARE INTRINSICALLY LINKED: THROUGH MITIGATION OF METABOLIC STRESS, T CELL DIFFERENTIATION CAN BE ALTERED TO PROMOTE MORE FUNCTIONAL CELLULAR FATES. 2021 4 5704 29 SINGLE-CELL RNA-SEQ REVEALS TOX AS A KEY REGULATOR OF CD8(+) T CELL PERSISTENCE IN CHRONIC INFECTION. PROGENITOR-LIKE CD8(+) T CELLS MEDIATE LONG-TERM IMMUNITY TO CHRONIC INFECTION AND CANCER AND RESPOND POTENTLY TO IMMUNE CHECKPOINT BLOCKADE. THESE CELLS SHARE TRANSCRIPTIONAL REGULATORS WITH MEMORY PRECURSOR CELLS, INCLUDING T CELL-SPECIFIC TRANSCRIPTION FACTOR 1 (TCF1), BUT IT IS UNCLEAR WHETHER THEY ADOPT DISTINCT PROGRAMS TO ADAPT TO THE IMMUNOSUPPRESSIVE ENVIRONMENT. BY COMPARING THE SINGLE-CELL TRANSCRIPTOMES AND EPIGENETIC PROFILES OF CD8(+) T CELLS RESPONDING TO ACUTE AND CHRONIC VIRAL INFECTIONS, WE FOUND THAT PROGENITOR-LIKE CD8(+) T CELLS BECAME DISTINCT FROM MEMORY PRECURSOR CELLS BEFORE THE PEAK OF THE T CELL RESPONSE. WE DISCOVERED A COEXPRESSION GENE MODULE CONTAINING TOX THAT EXHIBITED HIGHER TRANSCRIPTIONAL ACTIVITY ASSOCIATED WITH MORE ABUNDANT ACTIVE HISTONE MARKS IN PROGENITOR-LIKE CELLS THAN MEMORY PRECURSOR CELLS. MOREOVER, THYMOCYTE SELECTION-ASSOCIATED HIGH MOBILITY GROUP BOX PROTEIN TOX (TOX) PROMOTED THE PERSISTENCE OF ANTIVIRAL CD8(+) T CELLS AND WAS REQUIRED FOR THE PROGRAMMING OF PROGENITOR-LIKE CD8(+) T CELLS. THUS, LONG-TERM CD8(+) T CELL IMMUNITY TO CHRONIC VIRAL INFECTION REQUIRES UNIQUE TRANSCRIPTIONAL AND EPIGENETIC PROGRAMS ASSOCIATED WITH THE TRANSCRIPTION FACTOR TOX. 2019 5 923 22 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 6 4041 24 MACROPHAGE PLASTICITY IN DUCHENNE MUSCULAR DYSTROPHY: A NEXUS OF PATHOLOGICAL REMODELLING WITH THERAPEUTIC IMPLICATIONS. DUCHENNE MUSCULAR DYSTROPHY (DMD) IS CHARACTERIZED BY CHRONIC SKELETAL MUSCLE NECROSIS, LEADING TO MUSCLE REGENERATION FAILURE AND FIBROSIS. ALTHOUGH MACROPHAGES (MPS) ARE NORMALLY ESSENTIAL FOR MUSCLE REGENERATION, DYSREGULATED MP FUNCTION PROMOTES PATHOLOGICAL MUSCLE REMODELLING. INFILTRATING MPS CAN BE PREDOMINANTLY PRO-INFLAMMATORY (M1 BIASED), ANTI-INFLAMMATORY (M2 BIASED) OR OF A MIXED PHENOTYPE AND CAN ORIGINATE FROM THE ADULT BONE MARROW (MONOCYTE DEPENDENT) OR EMBRYONIC PRECURSORS (MONOCYTE INDEPENDENT). IN MDX MICE (GENETIC MODEL OF DMD) LACKING EITHER TOLL-LIKE RECEPTOR (TLR) 2 OR TLR4, IT IS FOUND THAT MP INFILTRATION OF DYSTROPHIC MUSCLE IS SIGNIFICANTLY REDUCED AND THAT THE MP PHENOTYPE IS SHIFTED TOWARD A MORE ANTI-INFLAMMATORY PROFILE. THIS IS ACCOMPANIED BY SIGNIFICANT IMPROVEMENTS IN MUSCLE HISTOLOGY AND FORCE PRODUCTION. LACK OF THE CHEMOKINE RECEPTOR CCR2, WHICH IMPEDES MONOCYTE RELEASE FROM THE BONE MARROW, LEADS TO SIMILAR BENEFICIAL EFFECTS IN MDX MICE. EVIDENCE WAS ALSO FOUND FOR TLR4-REGULATED INDUCTION OF TRAINED INNATE IMMUNITY IN MPS CULTURED FROM THE BONE MARROW OF MDX MICE BEFORE THEIR ENTRY INTO THE MUSCLE. THESE MPS EXHIBIT EPIGENETIC AND METABOLIC ALTERATIONS, ACCOMPANIED BY NON-SPECIFIC HYPER-RESPONSIVENESS TO MULTIPLE STIMULI, WHICH IS MANIFESTED BY POTENTIATED UPREGULATION OF BOTH PRO- AND ANTI-INFLAMMATORY GENES. IN SUMMARY, EXAGGERATED RECRUITMENT OF MONOCYTE-DERIVED MPS AND SIGNS OF TRAINED INNATE IMMUNITY AT THE LEVEL OF THE BONE MARROW ARE FEATURES OF THE IMMUNOPHENOTYPE ASSOCIATED WITH DYSTROPHIC MUSCLE DISEASE. THESE PHENOMENA ARE REGULATED BY TOLL-LIKE RECEPTORS THAT BIND ENDOGENOUS DAMAGE-ASSOCIATED MOLECULAR PATTERN (DAMP) MOLECULES, SUGGESTING THAT DAMP RELEASE FROM DYSTROPHIC MUSCLES MODULATES MP PLASTICITY AT THE BONE MARROW LEVEL THROUGH TOLL-LIKE RECEPTOR-DRIVEN MECHANISMS. 2022 7 6540 32 TRANSCRIPTIONAL, EPIGENETIC, AND FUNCTIONAL REPROGRAMMING OF MONOCYTES FROM NON-HUMAN PRIMATES FOLLOWING CHRONIC ALCOHOL DRINKING. CHRONIC HEAVY DRINKING (CHD) OF ALCOHOL IS A KNOWN RISK FACTOR FOR INCREASED SUSCEPTIBILITY TO BACTERIAL AND VIRAL INFECTION AS WELL AS IMPAIRED WOUND HEALING. EVIDENCE SUGGESTS THAT THESE DEFECTS ARE MEDIATED BY A DYSREGULATED INFLAMMATORY RESPONSE ORIGINATING FROM MYELOID CELLS, NOTABLY MONOCYTES AND MACROPHAGES, BUT THE MECHANISMS REMAIN POORLY UNDERSTOOD. OUR ABILITY TO STUDY CHD IS IMPACTED BY THE COMPLEXITIES OF HUMAN DRINKING PATTERNS AND BEHAVIOR AS WELL AS COMORBIDITIES AND CONFOUNDING RISK FACTORS FOR PATIENTS WITH ALCOHOL USE DISORDERS. TO OVERCOME THESE CHALLENGES, WE UTILIZED A TRANSLATIONAL RHESUS MACAQUE MODEL OF VOLUNTARY ETHANOL SELF-ADMINISTRATION THAT CLOSELY RECAPITULATES HUMAN DRINKING PATTERNS AND CHRONICITY. IN THIS STUDY, WE EXAMINED THE EFFECTS OF CHD ON BLOOD MONOCYTES IN CONTROL AND CHD FEMALE MACAQUES AFTER 12 MONTHS OF DAILY ETHANOL CONSUMPTION. WHILE MONOCYTES FROM CHD FEMALE MACAQUES GENERATED A HYPER-INFLAMMATORY RESPONSE TO EX VIVO LPS STIMULATION, THEIR RESPONSE TO E. COLI WAS DAMPENED. IN DEPTH SCRNA-SEQ ANALYSIS OF PURIFIED MONOCYTES REVEALED SIGNIFICANT SHIFTS IN CLASSICAL MONOCYTE SUBSETS WITH ACCUMULATION OF CELLS EXPRESSING MARKERS OF HYPOXIA (HIF1A) AND INFLAMMATION (NFKB SIGNALING PATHWAY) IN CHD MACAQUES. THE INCREASED PRESENCE OF MONOCYTE SUBSETS SKEWED TOWARDS INFLAMMATORY PHENOTYPES WAS COMPLEMENTED BY EPIGENETIC ANALYSIS, WHICH REVEALED HIGHER ACCESSIBILITY OF PROMOTER REGIONS THAT REGULATE GENES INVOLVED IN CYTOKINE SIGNALING PATHWAYS. COLLECTIVELY, DATA PRESENTED IN THIS MANUSCRIPT DEMONSTRATE THAT CHD SHIFTS CLASSICAL MONOCYTE SUBSET COMPOSITION AND PRIMES THE MONOCYTES TOWARDS A MORE HYPER-INFLAMMATORY RESPONSE TO LPS, BUT COMPROMISED PATHOGEN RESPONSE. 2021 8 3043 35 GENOME-WIDE ANALYSIS IDENTIFIES NR4A1 AS A KEY MEDIATOR OF T CELL DYSFUNCTION. T CELLS BECOME DYSFUNCTIONAL WHEN THEY ENCOUNTER SELF ANTIGENS OR ARE EXPOSED TO CHRONIC INFECTION OR TO THE TUMOUR MICROENVIRONMENT(1). THE FUNCTION OF T CELLS IS TIGHTLY REGULATED BY A COMBINATIONAL CO-STIMULATORY SIGNAL, AND DOMINANCE OF NEGATIVE CO-STIMULATION RESULTS IN T CELL DYSFUNCTION(2). HOWEVER, THE MOLECULAR MECHANISMS THAT UNDERLIE THIS DYSFUNCTION REMAIN UNCLEAR. HERE, USING AN IN VITRO T CELL TOLERANCE INDUCTION SYSTEM IN MICE, WE CHARACTERIZE GENOME-WIDE EPIGENETIC AND GENE EXPRESSION FEATURES IN TOLERANT T CELLS, AND SHOW THAT THEY ARE DISTINCT FROM EFFECTOR AND REGULATORY T CELLS. NOTABLY, THE TRANSCRIPTION FACTOR NR4A1 IS STABLY EXPRESSED AT HIGH LEVELS IN TOLERANT T CELLS. OVEREXPRESSION OF NR4A1 INHIBITS EFFECTOR T CELL DIFFERENTIATION, WHEREAS DELETION OF NR4A1 OVERCOMES T CELL TOLERANCE AND EXAGGERATES EFFECTOR FUNCTION, AS WELL AS ENHANCING IMMUNITY AGAINST TUMOUR AND CHRONIC VIRUS. MECHANISTICALLY, NR4A1 IS PREFERENTIALLY RECRUITED TO BINDING SITES OF THE TRANSCRIPTION FACTOR AP-1, WHERE IT REPRESSES EFFECTOR-GENE EXPRESSION BY INHIBITING AP-1 FUNCTION. NR4A1 BINDING ALSO PROMOTES ACETYLATION OF HISTONE 3 AT LYSINE 27 (H3K27AC), LEADING TO ACTIVATION OF TOLERANCE-RELATED GENES. THIS STUDY THUS IDENTIFIES NR4A1 AS A KEY GENERAL REGULATOR IN THE INDUCTION OF T CELL DYSFUNCTION, AND A POTENTIAL TARGET FOR TUMOUR IMMUNOTHERAPY. 2019 9 2067 26 EPIGENETIC CONTROL OF MACROPHAGE SHAPE TRANSITION TOWARDS AN ATYPICAL ELONGATED PHENOTYPE BY HISTONE DEACETYLASE ACTIVITY. INFLAMMATORY CHRONIC PATHOLOGIES ARE COMPLEX PROCESSES CHARACTERIZED BY AN IMBALANCE BETWEEN THE RESOLUTION OF THE INFLAMMATORY PHASE AND THE ESTABLISHMENT OF TISSUE REPAIR. THE MAIN PLAYERS IN THESE INFLAMMATORY PATHOLOGIES ARE BONE MARROW DERIVED MONOCYTES (BMDMS). HOWEVER, HOW MONOCYTE DIFFERENTIATION IS MODULATED TO GIVE RISE TO SPECIFIC MACROPHAGE SUBPOPULATIONS (M1 OR M2) THAT MAY EITHER MAINTAIN THE CHRONIC INFLAMMATORY PROCESS OR LEAD TO WOUND HEALING IS STILL UNCLEAR. CONSIDERING THAT INHIBITORS OF HISTONE DEACETYLASE (HDAC) HAVE AN ANTI-INFLAMMATORY ACTIVITY, WE ASKED WHETHER THIS ENZYME WOULD PLAY A ROLE ON MONOCYTE DIFFERENTIATION INTO M1 OR M2 PHENOTYPE AND IN THE CELL SHAPE TRANSITION THAT FOLLOWS. WE THEN INDUCED MURINE BONE MARROW PROGENITORS INTO MONOCYTE/MACROPHAGE DIFFERENTIATION PATHWAY USING MEDIA CONTAINING GM-CSF AND THE HDAC BLOCKER, TRICHOSTATIN A (TSA). WE FOUND THAT THE PHARMACOLOGICAL INHIBITION OF HDAC ACTIVITY LED TO A SHAPE TRANSITION FROM THE TYPICAL MACROPHAGE PANCAKE-LIKE SHAPE INTO AN ELONGATED MORPHOLOGY, WHICH WAS CORRELATED TO A MIXED M1/M2 PROFILE OF CYTOKINE AND CHEMOKINE SECRETION. OUR RESULTS PRESENT, FOR THE FIRST TIME, THAT HDAC ACTIVITY ACTS AS A REGULATOR OF MACROPHAGE DIFFERENTIATION IN THE ABSENCE OF LYMPHOCYTE STIMULI. WE PROPOSE THAT HDAC ACTIVITY DOWN REGULATES MACROPHAGE PLASTICITY FAVORING THE PRO-INFLAMMATORY PHENOTYPE. 2015 10 3373 29 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 11 1158 31 CONTEXT-DEPENDENT EPIGENETIC REGULATION OF NUCLEAR FACTOR OF ACTIVATED T CELLS 1 IN PANCREATIC PLASTICITY. BACKGROUND & AIMS: THE ABILITY OF EXOCRINE PANCREATIC CELLS TO CHANGE THE CELLULAR PHENOTYPE IS REQUIRED FOR TISSUE REGENERATION UPON INJURY, BUT ALSO CONTRIBUTES TO THEIR MALIGNANT TRANSFORMATION AND TUMOR PROGRESSION. WE INVESTIGATED CONTEXT-DEPENDENT SIGNALING AND TRANSCRIPTION MECHANISMS THAT DETERMINE PANCREATIC CELL FATE DECISIONS TOWARD REGENERATION AND MALIGNANCY. IN PARTICULAR, WE STUDIED THE FUNCTION AND REGULATION OF THE INFLAMMATORY TRANSCRIPTION FACTOR NUCLEAR FACTOR OF ACTIVATED T CELLS 1 (NFATC1) IN PANCREATIC CELL PLASTICITY AND TISSUE ADAPTATION. METHODS: WE ANALYZED CELL PLASTICITY DURING PANCREATIC REGENERATION AND TRANSFORMATION IN MICE WITH PANCREAS-SPECIFIC EXPRESSION OF A CONSTITUTIVELY ACTIVE FORM OF NFATC1, OR DEPLETION OF ENHANCER OF ZESTE 2 HOMOLOGUE 2 (EZH2), IN THE CONTEXT OF WILD-TYPE OR CONSTITUTIVELY ACTIVATE KRAS, RESPECTIVELY. ACUTE AND CHRONIC PANCREATITIS WERE INDUCED BY INTRAPERITONEAL INJECTION OF CAERULEIN. EZH2-DEPENDENT REGULATION OF NFATC1 EXPRESSION WAS STUDIED IN MOUSE IN HUMAN PANCREATIC TISSUE AND CELLS BY IMMUNOHISTOCHEMISTRY, IMMUNOBLOTTING, AND QUANTITATIVE REVERSE TRANSCRIPTION POLYMERASE CHAIN REACTION. WE USED GENETIC AND PHARMACOLOGIC APPROACHES OF EZH2 AND NFATC1 INHIBITION TO STUDY THE CONSEQUENCES OF PATHWAY DISRUPTION ON PANCREATIC MORPHOLOGY AND FUNCTION. EPIGENETIC MODIFICATIONS ON THE NFATC1 GENE WERE INVESTIGATED BY CHROMATIN IMMUNOPRECIPITATION ASSAYS. RESULTS: NFATC1 WAS RAPIDLY AND TRANSIENTLY INDUCED IN EARLY ADAPTATION TO ACINAR CELL INJURY IN HUMAN SAMPLES AND IN MICE, WHERE IT PROMOTED ACINAR CELL TRANSDIFFERENTIATION AND BLOCKED PROLIFERATION OF METAPLASTIC PANCREATIC CELLS. HOWEVER, IN LATE STAGES OF REGENERATION, NFATC1 WAS EPIGENETICALLY SILENCED BY EZH2-DEPENDENT HISTONE METHYLATION, TO ENABLE ACINAR CELL REDIFFERENTIATION AND PREVENT ORGAN ATROPHY AND EXOCRINE INSUFFICIENCY. IN CONTRAST, ONCOGENIC ACTIVATION OF KRAS SIGNALING IN PANCREATIC DUCTAL ADENOCARCINOMA CELLS REVERSED THE EZH2-DEPENDENT EFFECTS ON THE NFATC1 GENE AND WAS REQUIRED FOR EZH2-MEDIATED TRANSCRIPTIONAL ACTIVATION OF NFATC1. CONCLUSIONS: IN STUDIES OF HUMAN AND MOUSE PANCREATIC CELLS AND TISSUE, WE IDENTIFIED CONTEXT-SPECIFIC EPIGENETIC REGULATION OF NFATC1 ACTIVITY AS AN IMPORTANT MECHANISM OF PANCREATIC CELL PLASTICITY. INHIBITORS OF EZH2 MIGHT THEREFORE INTERFERE WITH ONCOGENIC ACTIVITY OF NFATC1 AND BE USED IN TREATMENT OF PANCREATIC DUCTAL ADENOCARCINOMA. 2017 12 2026 23 EPIGENETIC CHANGES IN BONE MARROW PROGENITOR CELLS INFLUENCE THE INFLAMMATORY PHENOTYPE AND ALTER WOUND HEALING IN TYPE 2 DIABETES. CLASSICALLY ACTIVATED (M1) MACROPHAGES ARE KNOWN TO PLAY A ROLE IN THE DEVELOPMENT OF CHRONIC INFLAMMATION ASSOCIATED WITH IMPAIRED WOUND HEALING IN TYPE 2 DIABETES (T2D); HOWEVER, THE MECHANISM RESPONSIBLE FOR THE DOMINANT PROINFLAMMATORY (M1) MACROPHAGE PHENOTYPE IN T2D WOUNDS IS UNKNOWN. SINCE EPIGENETIC ENZYMES CAN DIRECT MACROPHAGE PHENOTYPES, WE ASSESSED THE ROLE OF HISTONE METHYLATION IN BONE MARROW (BM) STEM/PROGENITOR CELLS IN THE PROGRAMMING OF MACROPHAGES TOWARD A PROINFLAMMATORY PHENOTYPE. WE HAVE FOUND THAT A REPRESSIVE HISTONE METHYLATION MARK, H3K27ME3, IS DECREASED AT THE PROMOTER OF THE IL-12 GENE IN BM PROGENITORS AND THIS EPIGENETIC SIGNATURE IS PASSED DOWN TO WOUND MACROPHAGES IN A MURINE MODEL OF GLUCOSE INTOLERANCE (DIET-INDUCED OBESE). THESE EPIGENETICALLY "PREPROGRAMMED" MACROPHAGES RESULT IN POISED MACROPHAGES IN PERIPHERAL TISSUE AND NEGATIVELY IMPACT WOUND REPAIR. WE FOUND THAT IN DIABETIC CONDITIONS THE H3K27 DEMETHYLASE JMJD3 DRIVES IL-12 PRODUCTION IN MACROPHAGES AND THAT IL-12 PRODUCTION CAN BE MODULATED BY INHIBITING JMJD3. USING HUMAN T2D TISSUE AND MURINE MODELS, WE HAVE IDENTIFIED A PREVIOUSLY UNRECOGNIZED MECHANISM BY WHICH MACROPHAGES ARE PROGRAMMED TOWARD A PROINFLAMMATORY PHENOTYPE, ESTABLISHING A PATTERN OF UNRESTRAINED INFLAMMATION ASSOCIATED WITH NONHEALING WOUNDS. HENCE, HISTONE DEMETHYLASE INHIBITOR-BASED THERAPY MAY REPRESENT A NOVEL TREATMENT OPTION FOR DIABETIC WOUNDS. 2015 13 991 28 CHRONIC STIMULATION DRIVES HUMAN NK CELL DYSFUNCTION AND EPIGENETIC REPROGRAMING. A POPULATION OF NATURAL KILLER (NK) CELLS EXPRESSING THE ACTIVATING RECEPTOR NKG2C AND THE MATURATION MARKER CD57 EXPANDS IN RESPONSE TO HUMAN CYTOMEGALOVIRUS (HCMV) INFECTION. CD3-CD56DIMCD57+NKG2C+ NK CELLS ARE SIMILAR TO CD8+ MEMORY T CELLS WITH RAPID AND ROBUST EFFECTOR FUNCTION UPON RE-STIMULATION, PERSISTENCE, AND EPIGENETIC REMODELING OF THE IFNG LOCUS. CHRONIC ANTIGEN STIMULATION DRIVES CD8+ MEMORY T CELL PROLIFERATION WHILE ALSO INDUCING GENOME-WIDE EPIGENETIC REPROGRAMING AND DYSFUNCTION. WE HYPOTHESIZED THAT CHRONIC STIMULATION COULD SIMILARLY INDUCE EPIGENETIC REPROGRAMING AND DYSFUNCTION IN NK CELLS. HERE WE SHOW THAT CHRONIC STIMULATION OF ADAPTIVE NK CELLS THROUGH NKG2C USING PLATE-BOUND AGONISTIC ANTIBODIES IN COMBINATION WITH IL-15 DROVE ROBUST PROLIFERATION AND ACTIVATION OF CD3-CD56DIMCD57+NKG2C+ NK CELLS WHILE SIMULTANEOUSLY INDUCING HIGH EXPRESSION OF THE CHECKPOINT INHIBITORY RECEPTORS LAG-3 AND PD-1. MARKED INDUCTION OF CHECKPOINT INHIBITORY RECEPTORS WAS ALSO OBSERVED ON THE SURFACE OF ADAPTIVE NK CELLS CO-CULTURED WITH HCMV-INFECTED ENDOTHELIAL CELLS. CHRONICALLY STIMULATED ADAPTIVE NK CELLS WERE DYSFUNCTIONAL WHEN CHALLENGED WITH TUMOR TARGETS. THESE CELLS EXHIBITED A PATTERN OF EPIGENETIC REPROGRAMING, WITH GENOME-WIDE ALTERATIONS IN DNA METHYLATION. OUR STUDY HAS IMPORTANT IMPLICATIONS FOR CANCER IMMUNOTHERAPY AND SUGGEST THAT EXHAUSTED NK CELLS COULD BE TARGETED WITH INHIBITORY CHECKPOINT RECEPTOR BLOCKADE. 2019 14 6365 27 THE ROLE OF METABOLIC DYSFUNCTION IN T-CELL EXHAUSTION DURING CHRONIC VIRAL INFECTION. T CELLS ARE IMPORTANT COMPONENTS OF ADAPTIVE IMMUNITY THAT PROTECT THE HOST AGAINST INVADING PATHOGENS DURING INFECTION. UPON RECOGNIZING THE ACTIVATION SIGNALS, NAIVE AND/OR MEMORY T CELLS WILL INITIATE CLONAL EXPANSION, TRIGGER DIFFERENTIATION INTO EFFECTOR POPULATIONS AND TRAFFIC TO THE INFLAMED SITES TO ELIMINATE PATHOGENS. HOWEVER, IN CHRONIC VIRAL INFECTIONS, SUCH AS THOSE CAUSED BY HUMAN IMMUNODEFICIENCY VIRUS (HIV), HEPATITIS B AND C (HBV AND HCV), T CELLS EXHIBIT IMPAIRED FUNCTION AND BECOME DIFFICULT TO CLEAR PATHOGENS IN A STATE KNOWN AS T-CELL EXHAUSTION. THE ACTIVATION AND FUNCTION PERSISTENCE OF T CELLS DEMAND FOR DYNAMIC CHANGES IN CELLULAR METABOLISM TO MEET THEIR BIOENERGETIC AND BIOSYNTHETIC DEMANDS, ESPECIALLY THE AUGMENTATION OF AEROBIC GLYCOLYSIS, WHICH NOT ONLY PROVIDE EFFICIENT ENERGY GENERATION, BUT ALSO FUEL MULTIPLE BIOCHEMICAL INTERMEDIATES THAT ARE ESSENTIAL FOR NUCLEOTIDE, AMINO ACID, FATTY ACID SYNTHESIS AND MITOCHONDRIA FUNCTION. CHANGES IN CELLULAR METABOLISM ALSO AFFECT THE FUNCTION OF EFFECTORS T CELLS THROUGH MODIFYING EPIGENETIC SIGNATURES. IT IS WIDELY ACCEPTED THAT THE DYSFUNCTION OF T CELL METABOLISM CONTRIBUTES GREATLY TO T-CELL EXHAUSTION. HERE, WE REVIEWED RECENT FINDINGS ON T CELLS METABOLISM UNDER CHRONIC VIRAL INFECTION, SEEKING TO REVEAL THE ROLE OF METABOLIC DYSFUNCTION PLAYED IN T-CELL EXHAUSTION. 2022 15 3182 37 HALLMARKS OF CD8(+) T CELL DYSFUNCTION ARE ESTABLISHED WITHIN HOURS OF TUMOR ANTIGEN ENCOUNTER BEFORE CELL DIVISION. TUMOR-SPECIFIC CD8+ T CELLS (TST) IN PATIENTS WITH CANCER ARE DYSFUNCTIONAL AND UNABLE TO HALT CANCER PROGRESSION. TST DYSFUNCTION, ALSO KNOWN AS EXHAUSTION, IS THOUGHT TO BE DRIVEN BY CHRONIC T CELL ANTIGEN RECEPTOR (TCR) STIMULATION OVER DAYS TO WEEKS. HOWEVER, WE KNOW LITTLE ABOUT THE INTERPLAY BETWEEN CD8(+) T CELL FUNCTION, CELL DIVISION AND EPIGENETIC REMODELING WITHIN HOURS OF ACTIVATION. HERE, WE ASSESSED EARLY CD8(+) T CELL DIFFERENTIATION, CELL DIVISION, CHROMATIN ACCESSIBILITY AND TRANSCRIPTION IN TUMOR-BEARING MICE AND ACUTELY INFECTED MICE. SURPRISINGLY, DESPITE ROBUST ACTIVATION AND PROLIFERATION, TST HAD NEAR COMPLETE EFFECTOR FUNCTION IMPAIRMENT EVEN BEFORE UNDERGOING CELL DIVISION AND HAD ACQUIRED HALLMARK CHROMATIN ACCESSIBILITY FEATURES PREVIOUSLY ASSOCIATED WITH LATER DYSFUNCTION/EXHAUSTION. MOREOVER, CONTINUED TUMOR/ANTIGEN EXPOSURE DROVE PROGRESSIVE EPIGENETIC REMODELING, 'IMPRINTING' THE DYSFUNCTIONAL STATE. OUR STUDY REVEALS THE RAPID DIVERGENCE OF T CELL FATE CHOICE BEFORE CELL DIVISION IN THE CONTEXT OF TUMORS VERSUS INFECTION. 2023 16 5795 24 STAT3 INDUCTION OF MIR-146B FORMS A FEEDBACK LOOP TO INHIBIT THE NF-KAPPAB TO IL-6 SIGNALING AXIS AND STAT3-DRIVEN CANCER PHENOTYPES. INTERLEUKIN-6 (IL-6)-MEDIATED ACTIVATION OF SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION 3 (STAT3) IS A MECHANISM BY WHICH CHRONIC INFLAMMATION CAN CONTRIBUTE TO CANCER AND IS A COMMON ONCOGENIC EVENT. WE DISCOVERED A PATHWAY, THE LOSS OF WHICH IS ASSOCIATED WITH PERSISTENT STAT3 ACTIVATION IN HUMAN CANCER. WE FOUND THAT THE GENE ENCODING THE TUMOR SUPPRESSOR MICRORNA MIR-146B IS A DIRECT STAT3 TARGET GENE, AND ITS EXPRESSION WAS INCREASED IN NORMAL BREAST EPITHELIAL CELLS BUT DECREASED IN TUMOR CELLS. METHYLATION OF THE MIR-146B PROMOTER, WHICH INHIBITED STAT3-MEDIATED INDUCTION OF EXPRESSION, WAS INCREASED IN PRIMARY BREAST CANCERS. MOREOVER, WE FOUND THAT MIR-146B INHIBITED NUCLEAR FACTOR KAPPAB (NF-KAPPAB)-DEPENDENT PRODUCTION OF IL-6, SUBSEQUENT STAT3 ACTIVATION, AND IL-6/STAT3-DRIVEN MIGRATION AND INVASION IN BREAST CANCER CELLS, THEREBY ESTABLISHING A NEGATIVE FEEDBACK LOOP. IN ADDITION, HIGHER EXPRESSION OF MIR-146B WAS POSITIVELY CORRELATED WITH PATIENT SURVIVAL IN BREAST CANCER SUBTYPES WITH INCREASED IL6 EXPRESSION AND STAT3 PHOSPHORYLATION. OUR RESULTS IDENTIFY AN EPIGENETIC MECHANISM OF CROSSTALK BETWEEN STAT3 AND NF-KAPPAB RELEVANT TO CONSTITUTIVE STAT3 ACTIVATION IN MALIGNANCY AND THE ROLE OF INFLAMMATION IN ONCOGENESIS. 2014 17 5592 20 ROLE OF TUMOR NECROSIS FACTOR-ALPHA IN THE HUMAN SYSTEMIC ENDOTOXIN-INDUCED TRANSCRIPTOME. TNFALPHA HAS BEEN IMPLICATED IN THE PATHOGENESIS OF VARIOUS INFLAMMATORY DISEASES. DIFFERENT STRATEGIES TO INHIBIT TNFALPHA IN PATIENTS WITH SEPSIS AND CHRONIC INFLAMMATORY CONDITIONS HAVE SHOWN CONTRASTING OUTCOMES. ALTHOUGH TNFALPHA INHIBITORS ARE WIDELY USED IN CLINICAL PRACTICE, THE IMPACT OF TNFALPHA ANTAGONISM ON WHITE BLOOD CELL GENE EXPRESSION PROFILES DURING ACUTE INFLAMMATION IN HUMANS IN VIVO HAS NOT BEEN ASSESSED. WE HERE LEVERAGED THE ESTABLISHED MODEL OF HUMAN ENDOTOXEMIA TO EXAMINE THE EFFECT OF THE TNFALPHA ANTAGONIST, ETANERCEPT, ON THE GENOME-WIDE TRANSCRIPTIONAL RESPONSES IN CIRCULATING LEUKOCYTES INDUCED BY INTRAVENOUS LPS ADMINISTRATION IN MALE SUBJECTS. ETANERCEPT PRE-TREATMENT RESULTED IN A MARKEDLY DAMPENED TRANSCRIPTIONAL RESPONSE TO LPS. GENE CO-EXPRESSION NETWORK ANALYSIS REVEALED THIS LPS-INDUCED TRANSCRIPTOME CAN BE CATEGORIZED AS TNFALPHA RESPONSIVE AND NON-RESPONSIVE MODULES. HIGHLY SIGNIFICANT TNFALPHA RESPONSIVE MODULES INCLUDE NF-KB SIGNALING, ANTIVIRAL RESPONSES AND T-CELL MEDIATED RESPONSES. WITHIN THESE TNFALPHA RESPONSIVE MODULES WE DELINEATE FUNDAMENTAL GENES INVOLVED IN EPIGENETIC MODIFICATIONS, TRANSCRIPTIONAL INITIATION AND ELONGATION. THUS, WE PROVIDE COMPREHENSIVE INFORMATION ABOUT MOLECULAR PATHWAYS THAT MIGHT BE TARGETED BY THERAPEUTIC INTERVENTIONS THAT SEEK TO INHIBIT TNFALPHA ACTIVITY DURING HUMAN INFLAMMATORY DISEASES. 2013 18 3759 21 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 19 6693 23 VARIABLE INDUCTION OF PRDM1 AND DIFFERENTIATION IN CHRONIC LYMPHOCYTIC LEUKEMIA IS ASSOCIATED WITH ANERGY. DESPITE ANTIGEN ENGAGEMENT AND INTACT B-CELL-RECEPTOR (BCR) SIGNALING, CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) CELLS FAIL TO UNDERGO TERMINAL DIFFERENTIATION. WE HYPOTHESIZED THAT SUCH FAILURE MAY BE DUE TO ANERGY, AS CLL CELLS EXHIBIT VARIABLE LEVELS OF NONRESPONSIVENESS TO SURFACE IGM STIMULATION THAT IS REVERSIBLE IN VITRO. MOREOVER, ANERGY IS ASSOCIATED WITH REDUCED DIFFERENTIATION CAPACITY IN NORMAL B CELLS. WE INVESTIGATED RESPONSES OF CLL CELLS TO TWO POTENT DIFFERENTIATION-PROMOTING AGENTS, IL-21 AND CYTOSINE GUANINE DINUCLEOTIDE-ENRICHED OLIGO-DEOXYNUCLEOTIDES. THE INDUCTION OF PR DOMAIN-CONTAINING PROTEIN 1 (PRDM1; ALSO KNOWN AS BLIMP-1), A CRITICAL REGULATOR OF PLASMACYTIC DIFFERENTIATION, BY THESE AGENTS WAS CLOSELY CORRELATED BUT VARIED BETWEEN INDIVIDUAL CASES, DESPITE FUNCTIONALLY INTACT IL-21 RECEPTOR- AND TOLL-LIKE RECEPTOR 9-MEDIATED SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION 3, AND NUCLEAR FACTOR-KAPPAB PATHWAYS. PRDM1 INDUCTION WAS INVERSELY CORRELATED WITH THE EXTENT OF ANERGY AS MEASURED BY THE ABILITY TO MOBILIZE INTRACELLULAR CA(2+) FOLLOWING BCR CROSSLINKING. PRDM1 RESPONSIVENESS WAS ASSOCIATED WITH OTHER MARKERS OF DIFFERENTIATION AND PROLIFERATION BUT NOT WITH DIFFERENCES IN APOPTOSIS. THE ABILITY TO INDUCE PRDM1 DID CORRELATE WITH DIFFERENTIAL TRANSCRIPTIONAL AND EPIGENETIC REGULATION OF THE PRDM1 GENE. THESE STUDIES EXTEND OUR UNDERSTANDING OF CLL PATHOBIOLOGY, DEMONSTRATING THAT REDUCED DIFFERENTIATION CAPACITY MAY BE A CONSEQUENCE OF ANERGY. EPIGENETIC DRUGS MAY OFFER POSSIBILITIES TO REACTIVATE PRDM1 EXPRESSION AS PART OF NOVEL DIFFERENTIATION THERAPY APPROACHES. 2014 20 590 26 BET BROMODOMAIN PROTEIN INHIBITION REVERSES CHIMERIC ANTIGEN RECEPTOR EXTINCTION AND REINVIGORATES EXHAUSTED T CELLS IN CHRONIC LYMPHOCYTIC LEUKEMIA. CHIMERIC ANTIGEN RECEPTOR (CAR) T CELLS HAVE INDUCED REMARKABLE ANTITUMOR RESPONSES IN B CELL MALIGNANCIES. SOME PATIENTS DO NOT RESPOND BECAUSE OF T CELL DEFICIENCIES THAT HAMPER THE EXPANSION, PERSISTENCE, AND EFFECTOR FUNCTION OF THESE CELLS. WE USED LONGITUDINAL IMMUNE PROFILING TO IDENTIFY PHENOTYPIC AND PHARMACODYNAMIC CHANGES IN CD19-DIRECTED CAR T CELLS IN PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). CAR EXPRESSION MAINTENANCE WAS ALSO INVESTIGATED BECAUSE THIS CAN AFFECT RESPONSE DURABILITY. CAR T CELL FAILURE WAS ACCOMPANIED BY PREEXISTING T CELL-INTRINSIC DEFECTS OR DYSFUNCTION ACQUIRED AFTER INFUSION. IN A SMALL SUBSET OF PATIENTS, CAR SILENCING WAS OBSERVED COINCIDENT WITH LEUKEMIA RELAPSE. USING A SMALL MOLECULE INHIBITOR, WE DEMONSTRATED THAT THE BROMODOMAIN AND EXTRA-TERMINAL (BET) FAMILY OF CHROMATIN ADAPTERS PLAYS A ROLE IN DOWNREGULATING CAR EXPRESSION. BET PROTEIN BLOCKADE ALSO AMELIORATED CAR T CELL EXHAUSTION AS MANIFESTED BY INHIBITORY RECEPTOR REDUCTION, ENHANCED METABOLIC FITNESS, INCREASED PROLIFERATIVE CAPACITY, AND ENRICHED TRANSCRIPTOMIC SIGNATURES OF T CELL REINVIGORATION. BET INHIBITION DECREASED LEVELS OF THE TET2 METHYLCYTOSINE DIOXYGENASE, AND FORCED EXPRESSION OF THE TET2 CATALYTIC DOMAIN ELIMINATED THE POTENCY-ENHANCING EFFECTS OF BET PROTEIN TARGETING IN CAR T CELLS, PROVIDING A MECHANISM LINKING BET PROTEINS AND T CELL DYSFUNCTION. THUS, MODULATING BET EPIGENETIC READERS MAY IMPROVE THE EFFICACY OF CELL-BASED IMMUNOTHERAPIES. 2021