1 3188 132 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 2 1472 28 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 3 3423 38 HUMAN PRIMARY AIRWAY EPITHELIAL CELLS ISOLATED FROM ACTIVE SMOKERS HAVE EPIGENETICALLY IMPAIRED ANTIVIRAL RESPONSES. BACKGROUND: CIGARETTE SMOKING (CS) IS THE MAIN RISK FACTOR FOR THE DEVELOPMENT OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) AND MOST COPD EXACERBATIONS ARE CAUSED BY RESPIRATORY INFECTIONS INCLUDING INFLUENZA. INFLUENZA INFECTIONS ARE MORE SEVERE IN SMOKERS. THE MECHANISM OF THE INCREASED RISK AND SEVERITY OF INFECTIONS IN SMOKERS IS LIKELY MULTIFACTORIAL, BUT CERTAINLY INCLUDES CHANGES IN IMMUNOLOGIC HOST DEFENSES. METHODS: WE INVESTIGATED RETINOIC ACID-INDUCIBLE PROTEIN I (RIG-I) AND INTERFERON (IFN) INDUCTION BY INFLUENZA A VIRUS (IAV) IN HUMAN BRONCHIAL EPITHELIAL CELLS (HBEC) ISOLATED FROM SMOKERS OR NONSMOKERS. SUBCULTURED HBEC CELLS WERE INFECTED WITH A/PUERTO RICO/8/1934 (PR8) IAV AT AN MOI OF 1. AFTER 24 H OF INFECTION, CELLS AND SUPERNATANTS WERE COLLECTED FOR QRT-PCR, IMMUNOBLOT OR ELISA TO DETERMINE RIG-I, TOLL-LIKE RECEPTOR3 (TLR3) AND IFN EXPRESSION LEVELS. RESULTS: IAV EXPOSURE INDUCED A VIGOROUS IFN-BETA, IFN-LAMBDA 1 AND IFN-LAMBDA 2/3 ANTIVIRAL RESPONSE IN HBEC FROM NONSMOKERS AND SIGNIFICANT INDUCTION OF RIG-I AND TLR3. IN CELLS FROM SMOKERS, VIRAL RIG-I AND TLR3 MRNA INDUCTION WAS REDUCED 87 AND 79 % COMPARED TO THE RESPONSE FROM NONSMOKERS. CS EXPOSURE HISTORY WAS ASSOCIATED WITH INHIBITION OF VIRAL INDUCTION OF THE IFN-BETA, IFN-LAMBDA1 AND IFN-LAMBDA 2/3 MRNA RESPONSE BY 85, 96 AND 95 %, RESPECTIVELY, FROM THAT SEEN IN HBEC FROM NONSMOKERS. THE DEMETHYLATING AGENT 5-AZA-2-DEOXYCYTIDINE REVERSED THE IMMUNOSUPPRESSIVE EFFECTS OF CS EXPOSURE IN HBEC SINCE VIRAL INDUCTION OF ALL THREE IFNS WAS RESTORED. IFN-BETA INDUCTION OF RIG-I AND TLR3 WAS ALSO SUPPRESSED IN THE CELLS FROM SMOKERS. CONCLUSION: OUR RESULTS SUGGEST THAT ACTIVE SMOKING REDUCES EXPRESSION OF ANTIVIRAL CYTOKINES IN PRIMARY HBEC CELLS. THIS EFFECT LIKELY OCCURS VIA DOWNREGULATION OF RIG-I AND TLR3 DUE TO SMOKE-INDUCED EPIGENETIC MODIFICATIONS. REDUCTION IN LUNG EPITHELIAL CELL RIG-I AND TLR3 RESPONSES MAY BE A MAJOR MECHANISM CONTRIBUTING TO THE INCREASED RISK AND SEVERITY OF VIRAL RESPIRATORY INFECTIONS IN SMOKERS AND TO VIRAL-MEDIATED ACUTE EXACERBATIONS OF COPD. 2016 4 6327 33 THE ROLE OF CD4(+) RESIDENT MEMORY T CELLS IN LOCAL IMMUNITY IN THE MUCOSAL TISSUE - PROTECTION VERSUS PATHOLOGY. MEMORY T CELLS ARE CRUCIAL FOR BOTH LOCAL AND SYSTEMIC PROTECTION AGAINST PATHOGENS OVER A LONG PERIOD OF TIME. THREE MAJOR SUBSETS OF MEMORY T CELLS; EFFECTOR MEMORY T (T(EM)) CELLS, CENTRAL MEMORY T (T(CM)) CELLS, AND TISSUE-RESIDENT MEMORY T (T(RM)) CELLS HAVE BEEN IDENTIFIED. THE MOST RECENTLY IDENTIFIED SUBSET, T(RM) CELLS, IS CHARACTERIZED BY THE EXPRESSION OF THE C-TYPE LECTIN CD69 AND/OR THE INTEGRIN CD103. T(RM) CELLS PERSIST LOCALLY AT SITES OF MUCOSAL TISSUE, SUCH AS THE LUNG, WHERE THEY PROVIDE FRONTLINE DEFENSE AGAINST VARIOUS PATHOGENS. IMPORTANTLY, HOWEVER, T(RM) CELLS ARE ALSO INVOLVED IN SHAPING THE PATHOLOGY OF INFLAMMATORY DISEASES. A NUMBER OF PIONEERING STUDIES REVEALED IMPORTANT ROLES OF CD8(+) T(RM) CELLS, PARTICULARLY THOSE IN THE LOCAL CONTROL OF VIRAL INFECTION. HOWEVER, THE PROTECTIVE FUNCTION AND PATHOGENIC ROLE OF CD4(+) T(RM) CELLS THAT RESIDE WITHIN THE MUCOSAL TISSUE REMAIN LARGELY UNKNOWN. IN THIS REVIEW, WE DISCUSS THE AMBIVALENT FEATURE OF CD4(+) T(RM) CELLS IN THE PROTECTIVE AND PATHOLOGICAL IMMUNE RESPONSES. WE ALSO REVIEW THE TRANSCRIPTIONAL AND EPIGENETIC CHARACTERISTICS OF CD4(+) T(RM) CELLS IN THE LUNG THAT HAVE BEEN ELUCIDATED BY RECENT TECHNICAL APPROACHES. A BETTER UNDERSTANDING OF THE FUNCTION OF CD4(+) T(RM) CELLS IS CRUCIAL FOR THE DEVELOPMENT OF BOTH EFFECTIVE VACCINATION AGAINST PATHOGENS AND NEW THERAPEUTIC STRATEGIES FOR INTRACTABLE INFLAMMATORY DISEASES, SUCH AS INFLAMMATORY BOWEL DISEASES AND CHRONIC ALLERGIC DISEASES. 2021 5 3538 34 IMMUNE REGULATION IN CHRONIC HEPATITIS C VIRUS INFECTION. THE IMMUNOLOGICAL RESULT OF INFECTION WITH HEPATITIS C VIRUS (HCV) DEPENDS ON THE DELICATE BALANCE BETWEEN A VIGOROUS IMMUNE RESPONSE THAT MAY CLEAR THE INFECTION, BUT WITH A RISK OF UNSPECIFIC INFLAMMATION AND, OR A LESS INFLAMMATORY RESPONSE THAT LEADS TO CHRONIC INFECTION. IN GENERAL, EXHAUSTION AND IMPAIRMENT OF CYTOTOXIC FUNCTION OF HCV-SPECIFIC T CELLS AND NK CELLS ARE FOUND IN PATIENTS WITH CHRONIC HCV INFECTION. IN CONTRAST, AN INCREASE IN IMMUNE REGULATORY FUNCTIONS IS FOUND PRIMARILY IN FORM OF INCREASED IL-10 PRODUCTION POSSIBLY DUE TO INCREASED LEVEL AND FUNCTION OF ANTI-INFLAMMATORY TREGS. THUS, THE MAJOR IMMUNE PLAYERS DURING CHRONIC HCV INFECTION ARE CHARACTERIZED BY A DECREASE OF CYTOTOXIC FUNCTION AND INCREASE OF INHIBITORY FUNCTIONS. THIS MAY BE AN APPROACH TO DIMINISH INTRAHEPATIC AND SYSTEMIC INFLAMMATION. FINALLY, THERE HAS BEEN INCREASING AWARENESS OF REGULATORY FUNCTIONS OF EPIGENETIC CHANGES IN CHRONIC HCV INFECTION. A VAST AMOUNT OF STUDIES HAVE REVEALED THE COMPLEXITY OF IMMUNE REGULATION IN CHRONIC HCV INFECTION, BUT THE INTERPLAY BETWEEN IMMUNE REGULATION IN VIRUS AND HOST REMAINS INCOMPLETELY UNDERSTOOD. THIS REVIEW PROVIDES AN OVERVIEW OF REGULATORY FUNCTIONS OF HCV-SPECIFIC T CELLS, NK CELLS, TREGS, IL-10, AND TGF-BETA, AS WELL AS EPIGENETIC CHANGES IN THE SETTING OF CHRONIC HCV INFECTION. 2016 6 6481 27 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 7 5059 29 PHENOTYPIC AND IMMUNOMETABOLIC ASPECTS ON STEM CELL MEMORY AND RESIDENT MEMORY CD8(+) T CELLS. THE IMMUNE SYSTEM, SMARTLY AND SURPRISINGLY, SAVES THE EXPOSURE OF A PARTICULAR PATHOGEN IN ITS MEMORY AND REACTS TO THE PATHOGEN VERY RAPIDLY, PREVENTING SERIOUS DISEASES. IMMUNOLOGISTS HAVE LONG BEEN FASCINATED BY UNDERSTANDING THE ABILITY TO RECALL AND RESPOND FASTER AND MORE VIGOROUSLY TO A PATHOGEN, KNOWN AS "MEMORY". T-CELL POPULATIONS CAN BE BETTER DESCRIBED BY USING MORE SOPHISTICATED TECHNIQUES TO DEFINE PHENOTYPE, TRANSCRIPTIONAL AND EPIGENETIC SIGNATURES AND METABOLIC PATHWAYS (SINGLE-CELL RESOLUTION), WHICH UNCOVERED THE HETEROGENEITY OF THE MEMORY T-COMPARTMENT. PHENOTYPE, EFFECTOR FUNCTIONS, MAINTENANCE, AND METABOLIC PATHWAYS HELP IDENTIFY THESE DIFFERENT SUBSETS. HERE, WE EXAMINE RECENT DEVELOPMENTS IN THE CHARACTERIZATION OF THE HETEROGENEITY OF THE MEMORY T CELL COMPARTMENT. IN PARTICULAR, WE FOCUS ON THE EMERGING ROLE OF CD8(+) T(RM) AND T(SCM) CELLS, PROVIDING EVIDENCE ON HOW THEIR IMMUNOMETABOLISM OR MODULATION CAN PLAY A VITAL ROLE IN THEIR GENERATION AND MAINTENANCE IN CHRONIC CONDITIONS SUCH AS INFECTIONS OR AUTOIMMUNE DISEASES. 2022 8 2409 26 EPIGENETIC SCARRING OF EXHAUSTED T CELLS HINDERS MEMORY DIFFERENTIATION UPON ELIMINATING CHRONIC ANTIGENIC STIMULATION. EXHAUSTED CD8 T CELLS (T(EX)) ARE A DISTINCT STATE OF T CELL DIFFERENTIATION ASSOCIATED WITH FAILURE TO CLEAR CHRONIC VIRUSES AND CANCER. IMMUNOTHERAPIES SUCH AS PD-1 BLOCKADE CAN REINVIGORATE T(EX) CELLS, BUT REINVIGORATION IS NOT DURABLE. A MAJOR UNANSWERED QUESTION IS WHETHER T(EX) CELLS DIFFERENTIATE INTO FUNCTIONAL DURABLE MEMORY T CELLS (T(MEM)) UPON ANTIGEN CLEARANCE. HERE, USING A MOUSE MODEL, WE FOUND THAT UPON ELIMINATING CHRONIC ANTIGENIC STIMULATION, T(EX) CELLS PARTIALLY (RE)ACQUIRE PHENOTYPIC AND TRANSCRIPTIONAL FEATURES OF T(MEM) CELLS. THESE 'RECOVERING' T(EX) CELLS ORIGINATED FROM THE T CELL FACTOR (TCF-1(+)) T(EX) PROGENITOR SUBSET. NEVERTHELESS, THE RECALL CAPACITY OF THESE RECOVERING T(EX) CELLS REMAINED COMPROMISED AS COMPARED TO T(MEM) CELLS. CHROMATIN-ACCESSIBILITY PROFILING REVEALED A FAILURE TO RECOVER CORE MEMORY EPIGENETIC CIRCUITS AND MAINTENANCE OF A LARGELY EXHAUSTED OPEN CHROMATIN LANDSCAPE. THUS, DESPITE SOME PHENOTYPIC AND TRANSCRIPTIONAL RECOVERY UPON ANTIGEN CLEARANCE, EXHAUSTION LEAVES DURABLE EPIGENETIC SCARS CONSTRAINING FUTURE IMMUNE RESPONSES. THESE RESULTS SUPPORT EPIGENETIC REMODELING INTERVENTIONS FOR T(EX) CELL-TARGETED IMMUNOTHERAPIES. 2021 9 991 29 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 10 2421 26 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 11 4567 40 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 12 501 24 ASSOCIATION OF ACCELEROMETER-MEASURED PHYSICAL ACTIVITY AND SEDENTARY TIME WITH EPIGENETIC MARKERS OF AGING. INTRODUCTION/PURPOSE: PHYSICAL ACTIVITY MAY INFLUENCE CHRONIC DISEASE RISK, IN PART, THROUGH EPIGENETIC MECHANISMS. PREVIOUS STUDIES HAVE DEMONSTRATED THAT AN ACUTE BOUT OF PHYSICAL ACTIVITY CAN INFLUENCE DNA METHYLATION STATUS. FEW STUDIES HAVE EXPLORED THE RELATIONSHIP BETWEEN HABITUAL, ACCELEROMETER-MEASURED PHYSICAL ACTIVITY OR SEDENTARY TIME WITH EPIGENETIC MARKERS OF AGING. METHODS: WE USED LINEAR REGRESSION TO EXAMINE CROSS-SECTIONAL ASSOCIATIONS OF ACCELEROMETER-MEASURED PHYSICAL ACTIVITY AND SEDENTARY TIME WITH EXTRINSIC AND INTRINSIC EPIGENETIC AGE ACCELERATION (EEAA AND IEAA) MODELS AND GRIMAGE MEASURED FROM BLOOD SAMPLES FROM FRAMINGHAM HEART STUDY PARTICIPANTS WITH ACCELEROMETRY AND DNA METHYLATION DATA ( N = 2435; MEAN AGE, 54.9 +/- 14.3; 46.0% MEN). RESIDUALS OF HANNUM-, HORVATH-, AND GRIMAGE-PREDICTED EPIGENETIC AGE WERE CALCULATED BY REGRESSING EPIGENETIC AGE ON CHRONOLOGICAL AGE. WE TOOK INTO ACCOUNT BLOOD CELL COMPOSITION FOR EEAA, IEAA, AND ADJGRIMAGE. MODERATE TO VIGOROUS PHYSICAL ACTIVITY WAS LOG-TRANSFORMED TO NORMALIZE ITS DISTRIBUTION. ADJUSTMENT MODELS ACCOUNTED FOR FAMILY STRUCTURE, AGE, SEX, SMOKING STATUS, COHORT-LABORATORY INDICATOR, AND ACCELEROMETER WEAR TIME. WE ADDITIONALLY EXPLORED ADJUSTMENT FOR BODY MASS INDEX (BMI). RESULTS: WALKING 1500 MORE STEPS PER DAY OR SPENDING 3 FEWER HOURS SEDENTARY WAS ASSOCIATED WITH >10 MONTHS LOWER GRIMAGE BIOLOGICAL AGE (OR ~1 MONTH LOWER ADJGRIMAGE, AFTER ADJUSTING FOR BLOOD CELLS, P < 0.05). EVERY 5 MIN.D -1 MORE MODERATE TO VIGOROUS PHYSICAL ACTIVITY WAS ASSOCIATED WITH 19-79 D OF LOWER GRIMAGE (4-23 D LOWER USING EEAA OR ADJGRIMAGE, P < 0.01). ADJUSTING FOR BMI ATTENUATED THESE RESULTS, BUT ALL STATISTICALLY SIGNIFICANT ASSOCIATIONS WITH ADJGRIMAGE REMAINED. CONCLUSIONS: GREATER HABITUAL PHYSICAL ACTIVITY AND LOWER SEDENTARY TIME WERE ASSOCIATED WITH LOWER EPIGENETIC AGE, WHICH WAS PARTIALLY EXPLAINED BY BMI. FURTHER RESEARCH SHOULD EXPLORE WHETHER CHANGES IN PHYSICAL ACTIVITY INFLUENCE METHYLATION STATUS AND WHETHER THOSE MODIFICATIONS INFLUENCE CHRONIC DISEASE RISK. 2023 13 5704 24 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 14 5015 36 PERSISTENCE OF SELF-REACTIVE CD8+ T CELLS IN THE CNS REQUIRES TOX-DEPENDENT CHROMATIN REMODELING. SELF-REACTIVE CD8(+) T CELLS ARE IMPORTANT MEDIATORS OF PROGRESSIVE TISSUE DAMAGE IN AUTOIMMUNE DISEASES, BUT THE MOLECULAR PROGRAM UNDERLYING THESE CELLS' FUNCTIONAL ADAPTATION IS UNCLEAR. HERE WE CHARACTERIZE THE TRANSCRIPTIONAL AND EPIGENETIC LANDSCAPE OF SELF-REACTIVE CD8(+) T CELLS IN A MOUSE MODEL OF PROTRACTED CENTRAL NERVOUS SYSTEM (CNS) AUTOIMMUNITY AND COMPARE IT TO POPULATIONS OF CNS-RESIDENT MEMORY CD8(+) T CELLS EMERGING FROM ACUTE VIRAL INFECTION. WE FIND THAT AUTOIMMUNE CD8(+) T CELLS PERSISTING AT SITES OF SELF-ANTIGEN EXHIBIT CHARACTERISTIC TRANSCRIPTIONAL REGULATION TOGETHER WITH DISTINCT EPIGENETIC REMODELING. THIS SELF-REACTIVE CD8(+) T CELL FATE DEPENDS ON THE TRANSCRIPTIONAL REGULATION BY THE DNA-BINDING HMG-BOX PROTEIN TOX WHICH REMODELS MORE THAN 400 GENOMIC REGIONS INCLUDING LOCI SUCH AS TCF7, WHICH IS CENTRAL TO STEMNESS OF CD8(+) T CELLS. CONTINUOUS EXPOSURE TO CNS SELF-ANTIGEN SUSTAINS TOX LEVELS IN SELF-REACTIVE CD8(+) T CELLS, WHEREAS GENETIC ABLATION OF TOX IN CD8(+) T CELLS RESULTS IN SHORTENED PERSISTENCE OF SELF-REACTIVE CD8(+) T CELLS IN THE INFLAMED CNS. OUR STUDY ESTABLISHES AND CHARACTERIZES THE GENETIC DIFFERENTIATION PROGRAM ENABLING CHRONIC T CELL-DRIVEN IMMUNOPATHOLOGY IN CNS AUTOIMMUNITY. 2021 15 5620 37 SCHRODINGER'S T CELLS: MOLECULAR INSIGHTS INTO STEMNESS AND EXHAUSTION. T CELL STEMNESS AND EXHAUSTION COEXIST AS TWO KEY CONTRASTING PHENOMENA DURING CHRONIC ANTIGEN STIMULATION, SUCH AS INFECTION, TRANSPLANT, CANCER, AND AUTOIMMUNITY. T CELL EXHAUSTION REFERS TO THE PROGRESSIVE LOSS OF EFFECTOR FUNCTION CAUSED BY CHRONIC ANTIGEN EXPOSURE. EXHAUSTED T (T(EX)) CELLS HIGHLY EXPRESS MULTIPLE INHIBITORY RECEPTORS AND EXHIBIT SEVERE DEFECTS IN CELL PROLIFERATION AND CYTOKINE PRODUCTION. THE TERM T CELL STEMNESS DESCRIBES THE STEM CELL-LIKE BEHAVIORS OF T CELLS, INCLUDING SELF-RENEWAL, MULTIPOTENCY, AND FUNCTIONAL PERSISTENCE. IT IS WELL ACCEPTED THAT NAIVE AND SOME MEMORY T CELL SUBSETS HAVE STEM CELL-LIKE PROPERTIES. WHEN INVESTIGATING THE EXHAUSTIVE DIFFERENTIATION OF T CELLS IN CHRONIC INFECTION AND CANCER, RECENT STUDIES HIGHLIGHTED THE STEMNESS OF "PRECURSORS OF EXHAUSTED" T (T(PEX)) CELLS PRIOR TO THEIR TERMINAL DIFFERENTIATION TO T(EX) CELLS. CLINICALLY SUCCESSFUL CHECKPOINT BLOCKADES FOR CANCER TREATMENT APPEAR TO INVIGORATE ANTITUMOR T(PEX) CELLS BUT NOT T(EX) CELLS. HERE WE DISCUSS THE TRANSCRIPTIONAL AND EPIGENETIC REGULATIONS OF T CELL STEMNESS AND EXHAUSTION, WITH A FOCUS ON HOW SYSTEMS IMMUNOLOGY WAS AND WILL BE UTILIZED TO DEFINE THE MOLECULAR BASIS UNDERLYING THE TRANSITION OF T(PEX) TO T(EX) CELLS. WE SUGGEST A "STEPWISE MODEL" OF T CELL STEMNESS AND EXHAUSTION, IN WHICH LOSS OF STEMNESS AND EXHAUSTION PROGRESSION ARE GRADUAL MULTI-STEP PROCESSES. WE PROVIDE PERSPECTIVES ON THE RESEARCH NEEDED TO DEFINE T CELL STEMNESS AND EXHAUSTION IN THE TRANSPLANTATION SETTING, IN WHICH ALLOGENIC T CELLS ARE ALSO CHRONICALLY EXPOSED TO ALLOANTIGENS. A BETTER UNDERSTANDING OF T CELL STEMNESS AND EXHAUSTION WILL SHED LIGHT ON DEVELOPING NOVEL STRATEGIES FOR IMMUNOTHERAPIES. 2021 16 4726 28 NOT-SO-OPPOSITE ENDS OF THE SPECTRUM: CD8(+) T CELL DYSFUNCTION ACROSS CHRONIC INFECTION, CANCER AND AUTOIMMUNITY. CD8(+) T CELLS ARE CRITICAL MEDIATORS OF CYTOTOXIC EFFECTOR FUNCTION IN INFECTION, CANCER AND AUTOIMMUNITY. IN CANCER AND CHRONIC VIRAL INFECTION, CD8(+) T CELLS UNDERGO A PROGRESSIVE LOSS OF CYTOKINE PRODUCTION AND CYTOTOXICITY, A STATE TERMED T CELL EXHAUSTION. IN AUTOIMMUNITY, AUTOREACTIVE CD8(+) T CELLS RETAIN THE CAPACITY TO EFFECTIVELY MEDIATE THE DESTRUCTION OF HOST TISSUES. ALTHOUGH THE CLINICAL OUTCOME DIFFERS IN EACH CONTEXT, CD8(+) T CELLS ARE CHRONICALLY EXPOSED TO ANTIGEN IN ALL THREE. THESE CHRONICALLY STIMULATED CD8(+) T CELLS SHARE SOME COMMON PHENOTYPIC FEATURES, AS WELL AS TRANSCRIPTIONAL AND EPIGENETIC PROGRAMMING, ACROSS DISEASE CONTEXTS. A BETTER UNDERSTANDING OF THESE CD8(+) T CELL STATES MAY REVEAL NOVEL STRATEGIES TO AUGMENT CLEARANCE OF CHRONIC VIRAL INFECTION AND CANCER AND TO MITIGATE SELF-REACTIVITY LEADING TO TISSUE DAMAGE IN AUTOIMMUNITY. 2021 17 6319 36 THE ROAD LESS TAKEN: LESS APPRECIATED PATHWAYS FOR MANIPULATING CD8(+) T CELL EXHAUSTION. EXHAUSTED CD8(+) T (TEX) CELLS ARE A DISTINCT CELL POPULATION THAT ARISE DURING PERSISTENT ANTIGEN EXPOSURE IN THE CONTEXT OF CHRONIC INFECTIONS AND CANCERS. ALTHOUGH CHARACTERIZED BY PROGRESSIVE LOSS OF EFFECTOR FUNCTIONS, HIGH AND SUSTAINED INHIBITORY RECEPTOR EXPRESSION AND DISTINCT TRANSCRIPTIONAL AND EPIGENETIC PROGRAMS, TEX CELLS ARE HETEROGENEOUS. AMONG THESE, A SELF-RENEWING TCF-1(+) TEX POPULATION, HAVING UNIQUE CHARACTERISTICS AND THE ABILITY TO RESPOND TO IMMUNE-CHECKPOINT BLOCKADE, GIVES RISE TO TCF-1(-) TERMINALLY TEX CELLS. THESE TCF-1(+) CELLS HAVE STEM CELL-LIKE PROPERTIES SIMILAR TO MEMORY T CELL POPULATIONS, BUT THE SIGNALS THAT REGULATE THE DEVELOPMENTAL PATHWAYS AND RELATIONSHIPS AMONG EXHAUSTED CELL POPULATIONS ARE STILL UNCLEAR. HERE, WE REVIEW OUR CURRENT UNDERSTANDING OF TEX CELL BIOLOGY, AND DISCUSS SOME LESS APPRECIATED MOLECULES AND PATHWAYS AFFECTING T CELL EXHAUSTION. WE HIGHLIGHT TWO CO-STIMULATORY RECEPTORS, CD226 AND CD137, AND THEIR ROLE IN INDUCING OR RESTRAINING T CELL EXHAUSTION, AS WELL AS SIGNALING PATHWAYS THAT MAY BE AMENABLE TO PHARMACOLOGICAL INHIBITION WITH A FOCUS ON PHOSPHOINOSITIDE-3 KINASE AND IL-2 PARTIAL AGONISTS. FINALLY, WE DISCUSS NOVEL METHODS THAT MAY INCREASE TCF-1(+) POPULATIONS AND THEREFORE IMPROVE IMMUNOTHERAPY RESPONSIVENESS. UNDERSTANDING FEATURES OF AND PATHWAYS TO EXHAUSTION HAS IMPORTANT IMPLICATIONS FOR THE SUCCESS OF IMMUNOTHERAPY, INCLUDING CHECKPOINT BLOCKADE AND ADOPTIVE T-CELL TRANSFER THERAPIES. 2022 18 771 39 CD8(+) T CELL EXHAUSTION. CD8(+) T CELLS ARE IMPORTANT FOR THE PROTECTIVE IMMUNITY AGAINST INTRACELLULAR PATHOGENS AND TUMOR. IN THE CASE OF CHRONIC INFECTION OR CANCER, CD8(+) T CELLS ARE EXPOSED TO PERSISTENT ANTIGEN AND/OR INFLAMMATORY SIGNALS. THIS EXCESSIVE AMOUNT OF SIGNALS OFTEN LEADS CD8(+) T CELLS TO GRADUAL DETERIORATION OF T CELL FUNCTION, A STATE CALLED "EXHAUSTION." EXHAUSTED T CELLS ARE CHARACTERIZED BY PROGRESSIVE LOSS OF EFFECTOR FUNCTIONS (CYTOKINE PRODUCTION AND KILLING FUNCTION), EXPRESSION OF MULTIPLE INHIBITORY RECEPTORS (SUCH AS PD-1 AND LAG3), DYSREGULATED METABOLISM, POOR MEMORY RECALL RESPONSE, AND HOMEOSTATIC PROLIFERATION. THESE ALTERED FUNCTIONS ARE CLOSELY RELATED WITH ALTERED TRANSCRIPTIONAL PROGRAM AND EPIGENETIC LANDSCAPE THAT CLEARLY DISTINGUISH EXHAUSTED T CELLS FROM NORMAL EFFECTOR AND MEMORY T CELLS. T CELL EXHAUSTION IS OFTEN ASSOCIATED WITH INEFFICIENT CONTROL OF PERSISTING INFECTIONS AND CANCERS, BUT RE-INVIGORATION OF EXHAUSTED T CELLS WITH INHIBITORY RECEPTOR BLOCKADE CAN PROMOTE IMPROVED IMMUNITY AND DISEASE OUTCOME. ACCUMULATING EVIDENCES SUPPORT THE THERAPEUTIC POTENTIAL OF TARGETING EXHAUSTED T CELLS. HOWEVER, EXHAUSTED T CELLS COMPRISE HETEROGENOUS CELL POPULATION WITH DISTINCT RESPONSIVENESS TO INTERVENTION. UNDERSTANDING MOLECULAR MECHANISM OF T CELL EXHAUSTION IS ESSENTIAL TO ESTABLISH RATIONAL IMMUNOTHERAPEUTIC INTERVENTIONS. 2019 19 4177 40 MEMORY T CELL, EXHAUSTION, AND TUMOR IMMUNITY. CD8(+)T CELLS ARE IMPORTANT IN PROTECTIVE IMMUNITY AGAINST INTRACELLULAR PATHOGENS AND TUMORS. IN CHRONIC INFECTIONS OR CANCER, CD8(+)T CELLS ARE CONSTANTLY EXPOSED TO ANTIGENS AND INFLAMMATORY SIGNALS. SUCH EXCESSIVE AND CONSTITUTIVE SIGNALS LEAD TO THE DETERIORATION OF T CELL FUNCTION, CALLED 'EXHAUSTION'. EXHAUSTED T CELLS ARE CHARACTERIZED BY LOW PROLIFERATION IN RESPONSE TO ANTIGEN STIMULATION, PROGRESSIVE LOSS OF EFFECTOR FUNCTION (CYTOKINE PRODUCTION AND KILLING FUNCTION), EXPRESSION OF MULTIPLE INHIBITORY RECEPTORS SUCH AS PD-1, TIM3, AND LAG3, AND METABOLIC ALTERATIONS FROM OXIDATIVE PHOSPHORYLATION TO GLYCOLYSIS. THESE DYSFUNCTIONS ARE ASSOCIATED WITH ALTERED TRANSCRIPTIONAL PROGRAMS AND EPIGENETIC REGULATIONS AND RECENT STUDIES SUGGESTED THAT NR4A AND TOX TRANSCRIPTION FACTORS ARE DEEPLY INVOLVED IN EXHAUSTION PHENOTYPES. HOWEVER, AN INCREASE THE EARLY MEMORY T CELLS INCLUDING STEM CELL MEMORY T (T(SCM)) CELLS IS CRITICAL FOR T CELL PERSISTENCE AND EFFICIENT TUMOR KILLING ESPECIALLY FOR ADOPTIVE CANCER IMMUNOTHERAPY SUCH AS CAR-T CELL THERAPY. AN INCREASING AMOUNT OF EVIDENCE SUPPORTS THE THERAPEUTIC POTENTIAL OF TARGETING EXHAUSTED T CELLS AND T(SCM) CELLS. WE HAVE BEGUN TO UNDERSTAND THE MOLECULAR MECHANISMS OF T CELL EXHAUSTION AND EARLY MEMORY FORMATION, AND THE CLINICAL APPLICATION OF CONVERTING EXHAUSTED T CELLS TO REJUVENATED EARLY MEMORY T CELLS IS THE GOAL OF OUR STUDY. 2020 20 330 23 ALPHA-SYNUCLEIN AND MECHANISMS OF EPIGENETIC REGULATION. SYNUCLEINOPATHIES ARE A GROUP OF NEURODEGENERATIVE DISEASES WITH COMMON PATHOLOGICAL LESIONS ASSOCIATED WITH THE EXCESSIVE ACCUMULATION AND ABNORMAL INTRACELLULAR DEPOSITION OF TOXIC SPECIES OF ALPHA-SYNUCLEIN. THE SHARED CLINICAL FEATURES ARE CHRONIC PROGRESSIVE DECLINE OF MOTOR, COGNITIVE, AND BEHAVIORAL FUNCTIONS. THESE DISORDERS INCLUDE PARKINSON'S DISEASE, DEMENTIA WITH LEWY BODY, AND MULTIPLE SYSTEM ATROPHY. VIGOROUS RESEARCH IN THE MECHANISMS OF PATHOLOGY OF THESE ILLNESSES IS CURRENTLY UNDER WAY TO FIND DISEASE-MODIFYING TREATMENT AND MOLECULAR MARKERS FOR EARLY DIAGNOSIS. ALPHA-SYNUCLEIN IS A PRONE-TO-AGGREGATE, SMALL AMYLOIDOGENIC PROTEIN WITH MULTIPLE ROLES IN SYNAPTIC VESICLE TRAFFICKING, NEUROTRANSMITTER RELEASE, AND INTRACELLULAR SIGNALING EVENTS. ITS EXPRESSION IS CONTROLLED BY SEVERAL MECHANISMS, ONE OF WHICH IS EPIGENETIC REGULATION. WHEN TRANSMITTED TO THE NUCLEUS, ALPHA-SYNUCLEIN BINDS TO DNA AND HISTONES AND PARTICIPATES IN EPIGENETIC REGULATORY FUNCTIONS CONTROLLING SPECIFIC GENE TRANSCRIPTION. HERE, WE DISCUSS THE VARIOUS ASPECTS OF ALPHA-SYNUCLEIN INVOLVEMENT IN EPIGENETIC REGULATION IN HEALTH AND DISEASES. 2023