1 545 94 ATTENUATED EPIGENETIC SUPPRESSION OF MUSCLE STEM CELL NECROPTOSIS IS REQUIRED FOR EFFICIENT REGENERATION OF DYSTROPHIC MUSCLES. SOMATIC STEM CELLS EXPAND MASSIVELY DURING TISSUE REGENERATION, WHICH MIGHT REQUIRE CONTROL OF CELL FITNESS, ALLOWING ELIMINATION OF NON-COMPETITIVE, POTENTIALLY HARMFUL CELLS. HOW OR IF SUCH CELLS ARE REMOVED TO RESTORE ORGAN FUNCTION IS NOT FULLY UNDERSTOOD. HERE, WE SHOW THAT A SUBSTANTIAL FRACTION OF MUSCLE STEM CELLS (MUSCS) UNDERGO NECROPTOSIS BECAUSE OF EPIGENETIC REWIRING DURING CHRONIC SKELETAL MUSCLE REGENERATION, WHICH IS REQUIRED FOR EFFICIENT REGENERATION OF DYSTROPHIC MUSCLES. INHIBITION OF NECROPTOSIS STRONGLY ENHANCES SUPPRESSION OF MUSC EXPANSION IN A NON-CELL-AUTONOMOUS MANNER. PREVENTION OF NECROPTOSIS IN MUSCS OF HEALTHY MUSCLES IS MEDIATED BY THE CHROMATIN REMODELER CHD4, WHICH DIRECTLY REPRESSES THE NECROPTOTIC EFFECTOR RIPK3, WHILE CHD4-DEPENDENT RIPK3 REPRESSION IS DRAMATICALLY ATTENUATED IN DYSTROPHIC MUSCLES. LOSS OF RIPK3 REPRESSION BY INACTIVATION OF CHD4 CAUSES MASSIVE NECROPTOSIS OF MUSCS, ABOLISHING REGENERATION. OUR STUDY DEMONSTRATES HOW PROGRAMMED CELL DEATH IN MUSCS IS TIGHTLY CONTROLLED TO ACHIEVE OPTIMAL TISSUE REGENERATION. 2020 2 2434 21 EPIGENETIC SILENCING OF RIPK3 IN HEPATOCYTES PREVENTS MLKL-MEDIATED NECROPTOSIS FROM CONTRIBUTING TO LIVER PATHOLOGIES. BACKGROUND & AIMS: NECROPTOSIS IS A HIGHLY INFLAMMATORY MODE OF CELL DEATH THAT HAS BEEN IMPLICATED IN CAUSING HEPATIC INJURY INCLUDING STEATOHEPATITIS/ NONALCOHOLIC STEATOHEPATITIS (NASH); HOWEVER, THE EVIDENCE SUPPORTING THESE CLAIMS HAS BEEN CONTROVERSIAL. A COMPREHENSIVE, FUNDAMENTAL UNDERSTANDING OF CELL DEATH PATHWAYS INVOLVED IN LIVER DISEASE CRITICALLY UNDERPINS RATIONAL STRATEGIES FOR THERAPEUTIC INTERVENTION. WE SOUGHT TO DEFINE THE ROLE AND RELEVANCE OF NECROPTOSIS IN LIVER PATHOLOGY. METHODS: SEVERAL ANIMAL MODELS OF HUMAN LIVER PATHOLOGY, INCLUDING DIET-INDUCED STEATOHEPATITIS IN MALE MICE AND DIVERSE INFECTIONS IN BOTH MALE AND FEMALE MICE, WERE USED TO DISSECT THE RELEVANCE OF NECROPTOSIS IN LIVER PATHOBIOLOGY. WE APPLIED NECROPTOTIC STIMULI TO PRIMARY MOUSE AND HUMAN HEPATOCYTES TO MEASURE THEIR SUSCEPTIBILITY TO NECROPTOSIS. PAIRED LIVER BIOSPECIMENS FROM PATIENTS WITH NASH, BEFORE AND AFTER INTERVENTION, WERE ANALYZED. DNA METHYLATION SEQUENCING WAS ALSO PERFORMED TO INVESTIGATE THE EPIGENETIC REGULATION OF RIPK3 EXPRESSION IN PRIMARY HUMAN AND MOUSE HEPATOCYTES. RESULTS: IDENTICAL INFECTION KINETICS AND PATHOLOGIC OUTCOMES WERE OBSERVED IN MICE DEFICIENT IN AN ESSENTIAL NECROPTOTIC EFFECTOR PROTEIN, MLKL, COMPARED WITH CONTROL ANIMALS. MICE LACKING MLKL WERE INDISTINGUISHABLE FROM WILD-TYPE MICE WHEN FED A HIGH-FAT DIET TO INDUCE NASH. UNDER ALL CONDITIONS TESTED, WE WERE UNABLE TO INDUCE NECROPTOSIS IN HEPATOCYTES. WE CONFIRMED THAT A CRITICAL ACTIVATOR OF NECROPTOSIS, RIPK3, WAS EPIGENETICALLY SILENCED IN MOUSE AND HUMAN PRIMARY HEPATOCYTES AND RENDERED THEM UNABLE TO UNDERGO NECROPTOSIS. CONCLUSIONS: WE HAVE PROVIDED COMPELLING EVIDENCE THAT NECROPTOSIS IS DISABLED IN HEPATOCYTES DURING HOMEOSTASIS AND IN THE PATHOLOGIC CONDITIONS TESTED IN THIS STUDY. 2022 3 2388 22 EPIGENETIC REMODELLING LICENCES ADULT CHOLANGIOCYTES FOR ORGANOID FORMATION AND LIVER REGENERATION. FOLLOWING SEVERE OR CHRONIC LIVER INJURY, ADULT DUCTAL CELLS (CHOLANGIOCYTES) CONTRIBUTE TO REGENERATION BY RESTORING BOTH HEPATOCYTES AND CHOLANGIOCYTES. WE RECENTLY SHOWED THAT DUCTAL CELLS CLONALLY EXPAND AS SELF-RENEWING LIVER ORGANOIDS THAT RETAIN THEIR DIFFERENTIATION CAPACITY INTO BOTH HEPATOCYTES AND DUCTAL CELLS. HOWEVER, THE MOLECULAR MECHANISMS BY WHICH ADULT DUCTAL-COMMITTED CELLS ACQUIRE CELLULAR PLASTICITY, INITIATE ORGANOIDS AND REGENERATE THE DAMAGED TISSUE REMAIN LARGELY UNKNOWN. HERE, WE DESCRIBE THAT DUCTAL CELLS UNDERGO A TRANSIENT, GENOME-WIDE, REMODELLING OF THEIR TRANSCRIPTOME AND EPIGENOME DURING ORGANOID INITIATION AND IN VIVO FOLLOWING TISSUE DAMAGE. TET1-MEDIATED HYDROXYMETHYLATION LICENCES DIFFERENTIATED DUCTAL CELLS TO INITIATE ORGANOIDS AND ACTIVATE THE REGENERATIVE PROGRAMME THROUGH THE TRANSCRIPTIONAL REGULATION OF STEM-CELL GENES AND REGENERATIVE PATHWAYS INCLUDING THE YAP-HIPPO SIGNALLING. OUR RESULTS ARGUE IN FAVOUR OF THE REMODELLING OF GENOMIC METHYLOME/HYDROXYMETHYLOME LANDSCAPES AS A GENERAL MECHANISM BY WHICH DIFFERENTIATED CELLS EXIT A COMMITTED STATE IN RESPONSE TO TISSUE DAMAGE. 2019 4 222 23 ACUTE LIVER STEATOSIS TRANSLATIONALLY CONTROLS THE EPIGENETIC REGULATOR MIER1 TO PROMOTE LIVER REGENERATION IN A STUDY WITH MALE MICE. THE EARLY PHASE LIPID ACCUMULATION IS ESSENTIAL FOR LIVER REGENERATION. HOWEVER, WHETHER THIS ACUTE LIPID ACCUMULATION CAN SERVE AS SIGNALS TO DIRECT LIVER REGENERATION RATHER THAN SIMPLY PROVIDING BUILDING BLOCKS FOR CELL PROLIFERATION REMAINS UNCLEAR. THROUGH IN VIVO CRISPR SCREENING, WE IDENTIFY MIER1 (MESODERM INDUCTION EARLY RESPONSE 1) AS A KEY EPIGENETIC REGULATOR THAT BRIDGES THE ACUTE LIPID ACCUMULATION AND CELL CYCLE GENE EXPRESSION DURING LIVER REGENERATION IN MALE ANIMALS. PHYSIOLOGICALLY, LIVER ACUTE LIPID ACCUMULATION INDUCES THE PHOSPHORYLATION OF EIF2S1(EUKARYOTIC TRANSLATION INITIATION FACTOR 2), WHICH CONSEQUENTLY ATTENUATED MIER1 TRANSLATION. MIER1 DOWNREGULATION IN TURN PROMOTES CELL CYCLE GENE EXPRESSION AND REGENERATION THROUGH CHROMATIN REMODELING. IMPORTANTLY, THE LIPIDS-EIF2S1-MIER1 PATHWAY IS IMPAIRED IN ANIMALS WITH CHRONIC LIVER STEATOSIS; WHEREAS MIER1 DEPLETION SIGNIFICANTLY IMPROVES REGENERATION IN THESE ANIMALS. TAKEN TOGETHER, OUR STUDIES IDENTIFY AN EPIGENETIC MECHANISM BY WHICH THE EARLY PHASE LIPID REDISTRIBUTION FROM ADIPOSE TISSUE TO LIVER DURING REGENERATION IMPACTS HEPATOCYTE PROLIFERATION, AND SUGGEST A POTENTIAL STRATEGY TO BOOST LIVER REGENERATION. 2023 5 4 27 "MIX OF MICS"- PHENOTYPIC AND BIOLOGICAL HETEROGENEITY OF "MULTIPOTENT" MUSCLE INTERSTITIAL CELLS (MICS). THE CAPACITY OF ADULT SKELETAL MUSCLE FOR REGENERATION APPEARS TO BE LIMITED, WITH PROGRESSIVE IMPAIRMENT IN REPAIR EFFICIENCY OF INJURED MUSCLES OBSERVED IN CHRONIC MUSCULAR DISORDERS AND DURING AGING. WHILE SATELLITE CELLS, THE COMMITTED ADULT MUSCLE STEM CELLS, ARE THE MAIN DIRECT CELL SOURCE SUPPORTING THE REGENERATIVE POTENTIAL OF ADULT SKELETAL MUSCLES, THE CHARACTERIZATION OF THE CELL TYPES AND SIGNALS THAT CONSTITUTE THE FUNCTIONAL "NICHE" OF SATELLITE CELLS IS CURRENTLY THE OBJECT OF INTENSE INVESTIGATION. RECENT STUDIES HAVE IDENTIFIED A FUNCTIONAL RELATIONSHIP BETWEEN SATELLITE CELLS AND VARIOUS CELL TYPES LOCATED IN KEY ANATOMICAL POSITION, SUCH AS THE INTERSTITIUM OF SKELETAL MUSCLES. THIS HETEROGENEOUS POPULATION OF MUSCLE INTERSTITIAL CELLS (MICS) APPEARS TO RETAIN AN INTRINSIC MULTIPOTENCY WITHIN THE MESODERMAL LINEAGE, AND THEIR DIRECT OR INDIRECT CONTRIBUTION TO MYOFIBER TURNOVER, REPAIR AND DEGENERATION HAS BEEN SUGGESTED BY MANY STUDIES THAT WILL BE REVIEWED HERE. GIVEN THE EXISTING GAP OF KNOWLEDGE ON LINEAGE IDENTITY AND FUNCTIONAL PROPERTIES OF MICS, THEIR DETAILED CHARACTERIZATION AT THE SINGLE CELL LEVEL HOLDS THE PROMISE TO PROVIDE KEY INSIGHT INTO THE COMPOSITION OF THIS HETEROGENEOUS POPULATION AND THE DYNAMIC TRANSITION THROUGH DISTINCT SUB-POPULATIONS IN HEALTHY, DISEASED AND AGING MUSCLES. THIS REVIEW PROVIDES AN OVERVIEW OF THE RESULTS OF VARIOUS STUDIES DESCRIBING THE PHENOTYPE AND THE FUNCTION OF CELLS ISOLATED FROM SKELETAL MUSCLE INTERSTITIUM, AND DISCUSSES THE IMPORTANCE OF SINGLE CELL TRANSCRIPTION PROFILING IN ORDER TO DECIPHER THE FUNCTIONAL AND PHENOTYPICAL HETEROGENEITY OF MUSCLE INTERSTITIAL CELLS (MICS). 2012 6 2002 22 EPIGENETIC AND POST-TRANSCRIPTIONAL REPRESSION SUPPORT METABOLIC SUPPRESSION IN CHRONICALLY HYPOXIC GOLDFISH. GOLDFISH ENTER A HYPOMETABOLIC STATE TO SURVIVE CHRONIC HYPOXIA. WE RECENTLY DESCRIBED TISSUE-SPECIFIC CONTRIBUTIONS OF MEMBRANE LIPID COMPOSITION REMODELING AND MITOCHONDRIAL FUNCTION TO METABOLIC SUPPRESSION ACROSS DIFFERENT GOLDFISH TISSUES. HOWEVER, THE MOLECULAR AND ESPECIALLY EPIGENETIC FOUNDATIONS OF HYPOXIA TOLERANCE IN GOLDFISH UNDER METABOLIC SUPPRESSION ARE NOT WELL UNDERSTOOD. HERE WE SHOW THAT COMPONENTS OF THE MOLECULAR OXYGEN-SENSING MACHINERY ARE ROBUSTLY ACTIVATED ACROSS TISSUES IRRESPECTIVE OF HYPOXIA DURATION. INDUCTION OF GENE EXPRESSION OF ENZYMES INVOLVED IN DNA METHYLATION TURNOVER AND MICRORNA BIOGENESIS SUGGEST A ROLE FOR EPIGENETIC TRANSCRIPTIONAL AND POST-TRANSCRIPTIONAL SUPPRESSION OF GENE EXPRESSION IN THE HYPOXIA-ACCLIMATED BRAIN. CONVERSELY, MECHANISTIC TARGET OF RAPAMYCIN-DEPENDENT TRANSLATIONAL MACHINERY ACTIVITY IS NOT REDUCED IN LIVER AND WHITE MUSCLE, SUGGESTING THIS PATHWAY DOES NOT CONTRIBUTE TO LOWERING CELLULAR ENERGY EXPENDITURE. FINALLY, MOLECULAR EVIDENCE SUPPORTS PREVIOUSLY REPORTED CHRONIC HYPOXIA-DEPENDENT CHANGES IN MEMBRANE CHOLESTEROL, LIPID METABOLISM AND MITOCHONDRIAL FUNCTION VIA CHANGES IN TRANSCRIPTS INVOLVED IN CHOLESTEROL BIOSYNTHESIS, BETA-OXIDATION, AND MITOCHONDRIAL FUSION IN MULTIPLE TISSUES. OVERALL, THIS STUDY SHOWS THAT CHRONIC HYPOXIA ROBUSTLY INDUCES EXPRESSION OF OXYGEN-SENSING MACHINERY ACROSS TISSUES, INDUCES REPRESSIVE TRANSCRIPTIONAL AND POST-TRANSCRIPTIONAL EPIGENETIC MARKS ESPECIALLY IN THE CHRONIC HYPOXIA-ACCLIMATED BRAIN AND SUPPORTS A ROLE FOR MEMBRANE REMODELING AND MITOCHONDRIAL FUNCTION AND DYNAMICS IN PROMOTING METABOLIC SUPPRESSION. 2022 7 5889 18 SYSTEMS APPROACHES TO MODELING CHRONIC MUCOSAL INFLAMMATION. THE RESPIRATORY MUCOSA IS A MAJOR COORDINATOR OF THE INFLAMMATORY RESPONSE IN CHRONIC AIRWAY DISEASES, INCLUDING ASTHMA AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). SIGNALS PRODUCED BY THE CHRONIC INFLAMMATORY PROCESS INDUCE EPITHELIAL MESENCHYMAL TRANSITION (EMT) THAT DRAMATICALLY ALTERS THE EPITHELIAL CELL PHENOTYPE. THE EFFECTS OF EMT ON EPIGENETIC REPROGRAMMING AND THE ACTIVATION OF TRANSCRIPTIONAL NETWORKS ARE KNOWN, ITS EFFECTS ON THE INNATE INFLAMMATORY RESPONSE ARE UNDEREXPLORED. WE USED A MULTIPLEX GENE EXPRESSION PROFILING PLATFORM TO INVESTIGATE THE PERTURBATIONS OF THE INNATE PATHWAYS INDUCED BY TGF BETA IN A PRIMARY AIRWAY EPITHELIAL CELL MODEL OF EMT. EMT HAD DRAMATIC EFFECTS ON THE INDUCTION OF THE INNATE PATHWAY AND THE COUPLING INTERVAL OF THE CANONICAL AND NONCANONICAL NF- KAPPA B PATHWAYS. SIMULATION EXPERIMENTS DEMONSTRATE THAT RAPID, COORDINATED CAP-INDEPENDENT TRANSLATION OF TRAF-1 AND NF- KAPPA B2 IS REQUIRED TO REDUCE THE NONCANONICAL PATHWAY COUPLING INTERVAL. EXPERIMENTS USING AMANTADINE CONFIRMED THE PREDICTION THAT TRAF-1 AND NF- KAPPA B2/P100 PRODUCTION IS MEDIATED BY AN IRES-DEPENDENT MECHANISM. THESE DATA INDICATE THAT THE EPIGENETIC CHANGES PRODUCED BY EMT INDUCE DYNAMIC STATE CHANGES OF THE INNATE SIGNALING PATHWAY. FURTHER APPLICATIONS OF SYSTEMS APPROACHES WILL PROVIDE UNDERSTANDING OF THIS COMPLEX PHENOTYPE THROUGH DETERMINISTIC MODELING AND MULTIDIMENSIONAL (GENOMIC AND PROTEOMIC) PROFILING. 2013 8 2446 16 EPIGENETIC STRATEGIES SYNERGIZE WITH PD-L1/PD-1 TARGETED CANCER IMMUNOTHERAPIES TO ENHANCE ANTITUMOR RESPONSES. IMMUNOTHERAPY STRATEGIES TARGETING THE PROGRAMMED CELL DEATH LIGAND 1 (PD-L1)/PROGRAMMED CELL DEATH 1 (PD-1) PATHWAY IN CLINICAL TREATMENTS HAVE ACHIEVED REMARKABLE SUCCESS IN TREATING MULTIPLE TYPES OF CANCER. HOWEVER, OWING TO THE HETEROGENEITY OF TUMORS AND INDIVIDUAL IMMUNE SYSTEMS, PD-L1/PD-1 BLOCKADE STILL SHOWS SLOW RESPONSE RATES IN CONTROLLING MALIGNANCIES IN MANY PATIENTS. ACCUMULATING EVIDENCE HAS SHOWN THAT AN EFFECTIVE RESPONSE TO ANTI-PD-L1/ANTI-PD-1 THERAPY REQUIRES ESTABLISHING AN INTEGRATED IMMUNE CYCLE. DAMAGE IN ANY STEP OF THE IMMUNE CYCLE IS ONE OF THE MOST IMPORTANT CAUSES OF IMMUNOTHERAPY FAILURE. IMPAIRMENTS IN THE IMMUNE CYCLE CAN BE RESTORED BY EPIGENETIC MODIFICATION, INCLUDING REPROGRAMMING THE ENVIRONMENT OF TUMOR-ASSOCIATED IMMUNITY, ELICITING AN IMMUNE RESPONSE BY INCREASING THE PRESENTATION OF TUMOR ANTIGENS, AND BY REGULATING T CELL TRAFFICKING AND REACTIVATION. THUS, A RATIONAL COMBINATION OF PD-L1/PD-1 BLOCKADE AND EPIGENETIC AGENTS MAY OFFER GREAT POTENTIAL TO RETRAIN THE IMMUNE SYSTEM AND TO IMPROVE CLINICAL OUTCOMES OF CHECKPOINT BLOCKADE THERAPY. 2020 9 19 21 5-AZACYTYDINE AND RESVERATROL REVERSE SENESCENCE AND AGEING OF ADIPOSE STEM CELLS VIA MODULATION OF MITOCHONDRIAL DYNAMICS AND AUTOPHAGY. OBESITY AND ENDOCRINE DISORDERS HAVE BECOME PREVALENT ISSUES IN THE FIELD OF BOTH HUMAN AND VETERINARY MEDICINE. EQUINE METABOLIC SYNDROME IS A COMPLEX DISORDER INVOLVING ALTERNATION IN METABOLISM AND CHRONIC SYSTEMIC INFLAMMATION. IT HAS BEEN SHOWN THAT UNFAVOURABLE MICROENVIRONMENT OF INFLAMED ADIPOSE TISSUE NEGATIVELY AFFECTS ADIPOSE STEM CELL POPULATION (ASC) RESIDING WITHIN, MARKEDLY LIMITING THEIR THERAPEUTIC POTENTIAL. ASCS(EMS) ARE CHARACTERIZED BY INCREASED SENESCENCE APOPTOSIS, EXCESSIVE ACCUMULATION OF REACTIVE OXYGEN SPECIES (ROS), MITOCHONDRIA DETERIORATION AND "AUTOPHAGIC FLUX." THE AIM OF THE PRESENT STUDY WAS TO EVALUATE WHETHER TREATMENT OF ASCS(EMS) WITH A COMBINATION OF 5-AZACYTYDINE (AZA) AND RESVERATROL (RES) WOULD REVERSE AGED PHENOTYPE OF THESE CELLS. FOR THIS REASON, WE PERFORMED THE FOLLOWING ANALYZES: MOLECULAR BIOLOGY (RT-PCR), MICROSCOPIC (IMMUNOFLUORESCENCE, TEM) AND FLOW CYTOMETRY (JC-1, ROS, KI67). WE EVALUATED THE MITOCHONDRIAL STATUS, DYNAMICS AND CLEARANCE AS WELL AS AUTOPHAGIC PATHWAYS. FURTHERMORE, WE INVESTIGATED EPIGENETIC ALTERNATIONS IN TREATED CELLS BY MEASURING THE EXPRESSION OF TET GENES AND ANALYSIS OF DNA METHYLATION STATUS. WE HAVE DEMONSTRATED THAT AZA/RES TREATMENT OF ASCS(EMS) IS ABLE TO REJUVENATE THESE CELLS BY MODULATING MITOCHONDRIAL DYNAMICS, IN PARTICULAR BY PROMOTING MITOCHONDRIAL FUSION OVER FISSION. AFTER AZA/RES TREATMENT, ASCS(EMS) WERE CHARACTERIZED BY INCREASED PROLIFERATION RATE, DECREASED APOPTOSIS AND SENESCENCE AND LOWER ROS ACCUMULATION. OUR FINDINGS OFFER A NOVEL APPROACH AND POTENTIAL TARGETS FOR THE BENEFICIAL EFFECTS OF AZA/RES IN AMELIORATING STEM CELL DYSFUNCTIONS. 2019 10 3167 31 GROUP 1 METABOTROPIC GLUTAMATE RECEPTOR EXPRESSION DEFINES A T CELL MEMORY POPULATION DURING CHRONIC TOXOPLASMA INFECTION THAT ENHANCES IFN-GAMMA AND PERFORIN PRODUCTION IN THE CNS. WITHIN THE BRAIN, A PRO-INFLAMMATORY RESPONSE IS ESSENTIAL TO PREVENT CLINICAL DISEASE DUE TO TOXOPLASMA GONDII REACTIVATION. INFECTION IN THE IMMUNOCOMPROMISED LEADS TO LETHAL TOXOPLASMIC ENCEPHALITIS WHILE IN THE IMMUNOCOMPETENT, THERE IS PERSISTENT LOW-GRADE INFLAMMATION WHICH IS DEVOID OF CLINICAL SYMPTOMS. THIS SIGNIFIES THAT THERE IS A WELL-BALANCED AND REGULATED INFLAMMATORY RESPONSE TO T. GONDII IN THE BRAIN. T CELLS ARE THE DOMINANT IMMUNE CELLS THAT PREVENT CLINICAL DISEASE, AND THIS IS MEDIATED THROUGH THE SECRETION OF EFFECTOR MOLECULES SUCH AS PERFORINS AND IFN-GAMMA. THE PRESENCE OF COGNATE ANTIGEN, THE EXPRESSION OF SURVIVAL CYTOKINES, AND THE ALTERATION OF THE EPIGENETIC LANDSCAPE DRIVE THE DEVELOPMENT OF MEMORY T CELLS. HOWEVER, SPECIFIC EXTRINSIC SIGNALS THAT PROMOTE THE FORMATION AND MAINTENANCE OF MEMORY T CELLS WITHIN TISSUE ARE POORLY UNDERSTOOD. DURING CHRONIC INFECTION, THERE IS AN INCREASE IN EXTRACELLULAR GLUTAMATE THAT, DUE TO ITS FUNCTION AS AN EXCITATORY NEUROTRANSMITTER, IS NORMALLY TIGHTLY CONTROLLED IN THE CNS. HERE WE DEMONSTRATE THAT CD8(+) T CELLS FROM THE T. GONDII-INFECTED BRAIN PARENCHYMA ARE ENRICHED FOR METABOTROPIC GLUTAMATE RECEPTORS (MGLUR'S). CHARACTERIZATION STUDIES DETERMINED THAT MGLUR(+) EXPRESSION BY CD8(+) T CELLS DEFINES A DISTINCT MEMORY POPULATION AT THE TRANSCRIPTIONAL AND PROTEIN LEVEL. FINALLY, USING RECEPTOR ANTAGONISTS AND AGONISTS WE DEMONSTRATE MGLUR SIGNALING IS REQUIRED FOR OPTIMAL CD8(+) T CELL PRODUCTION OF THE EFFECTOR CYTOKINE IFNGAMMA. THIS WORK SUGGESTS THAT GLUTAMATE IS AN IMPORTANT ENVIRONMENTAL SIGNAL OF INFLAMMATION THAT PROMOTES T CELL FUNCTION. UNDERSTANDING GLUTAMATE'S INFLUENCE ON T CELLS IN THE BRAIN CAN PROVIDE INSIGHTS INTO THE MECHANISMS THAT GOVERN PROTECTIVE IMMUNITY AGAINST CNS-INFILTRATING PATHOGENS AND NEUROINFLAMMATION. 2023 11 4210 18 METFORMIN AND VITAMIN D MODULATE INFLAMMATION AND AUTOPHAGY DURING ADIPOSE-DERIVED STEM CELL DIFFERENTIATION. ADIPOSE-DERIVED STEM CELLS (ADSCS) CAME OUT FROM THE REGENERATIVE MEDICINE LANDSCAPE FOR THEIR ABILITY TO DIFFERENTIATE INTO SEVERAL PHENOTYPES, CONTRIBUTING TO TISSUE REGENERATION BOTH IN VITRO AND IN VIVO. DYSREGULATION IN STEM CELL RECRUITMENT AND DIFFERENTIATION DURING ADIPOGENESIS IS LINKED TO A CHRONIC LOW-GRADE INFLAMMATION AND MACROPHAGE INFILTRATION INSIDE THE ADIPOSE TISSUE, INSULIN RESISTANCE, CARDIOVASCULAR DISEASE AND OBESITY. IN THE PRESENT PAPER WE AIMED TO EVALUATE THE ROLE OF METFORMIN AND VITAMIN D, ALONE OR IN COMBINATION, IN MODULATING INFLAMMATION AND AUTOPHAGY IN ADSCS DURING ADIPOGENIC COMMITMENT. ADSCS WERE CULTURED FOR 21 DAYS IN THE PRESENCE OF A SPECIFIC ADIPOGENIC DIFFERENTIATION MEDIUM, TOGETHER WITH METFORMIN, OR VITAMIN D, OR BOTH. WE THEN ANALYZED THE EXPRESSION OF FOXO1 AND HEAT SHOCK PROTEINS (HSP) AND THE SECRETION OF PROINFLAMMATORY CYTOKINES IL-6 AND TNF-ALPHA BY ELISA. AUTOPHAGY WAS ALSO ASSESSED BY SPECIFIC WESTERN BLOT ANALYSIS OF ATG12, LC3B I, AND LC3B II EXPRESSION. OUR RESULTS SHOWED THE ABILITY OF THE CONDITIONED MEDIA TO MODULATE ADIPOGENIC DIFFERENTIATION, FINELY TUNING THE INFLAMMATORY RESPONSE AND AUTOPHAGY. WE OBSERVED A MODULATION IN HSP MRNA LEVELS, AND A SIGNIFICANT DOWNREGULATION IN CYTOKINE SECRETION. TAKEN TOGETHER, OUR FINDINGS SUGGEST THE POSSIBLE APPLICATION OF THESE MOLECULES IN CLINICAL PRACTICE TO COUNTERACT UNCONTROLLED LIPOGENESIS AND PREVENT OBESITY AND OBESITY-RELATED METABOLIC DISORDERS. 2021 12 6057 15 THE DARK SIDE OF REGULATORY T CELLS IN PSORIASIS. PSORIASIS IS A HEREDITARY DISEASE ELICITED BY CHRONIC ACTIVATION OF CUTANEOUS T CELLS. DELINEATING THE MECHANISTIC INTERPLAY OF THE CELL SUBSETS INVOLVED IS KEY TO DEVELOPING THE NEXT GENERATION OF EFFECTIVE TREATMENTS. IN THIS ISSUE, BOVENSCHEN ET AL. REPORT THAT REGULATORY T CELLS MAINTAIN A FINE BALANCE BETWEEN THE TRANSCRIPTION FACTORS FOXP3 AND RORGAMMAT. IN PATIENTS WITH PSORIASIS, TREGS READILY TURN INTO IL-17-EXPRESSING CELLS, THUS POTENTIALLY PERPETUATING THE INFLAMMATORY PROCESS THAT CHARACTERIZES THE DISEASE. RESULTS DEMONSTRATING THAT THE HISTONE/PROTEIN DEACETYLATION INHIBITOR TRICHOSTATIN A CAN BLOCK THIS CONVERSION SUGGEST THAT AN EPIGENETIC MODIFICATION MAY UNDERLIE REGULATORY T-CELL PLASTICITY. 2011 13 1326 20 DEPLETION OF NUCLEAR HISTONE H2A VARIANTS IS ASSOCIATED WITH CHRONIC DNA DAMAGE SIGNALING UPON DRUG-EVOKED SENESCENCE OF HUMAN SOMATIC CELLS. CELLULAR SENESCENCE IS ASSOCIATED WITH GLOBAL CHROMATIN CHANGES, ALTERED GENE EXPRESSION, AND ACTIVATION OF CHRONIC DNA DAMAGE SIGNALING. THESE EVENTS ULTIMATELY LEAD TO MORPHOLOGICAL AND PHYSIOLOGICAL TRANSFORMATIONS IN PRIMARY CELLS. IN THIS STUDY, WE SHOW THAT CHRONIC DNA DAMAGE SIGNALS CAUSED BY GENOTOXIC STRESS IMPACT THE EXPRESSION OF HISTONES H2A FAMILY MEMBERS AND LEAD TO THEIR DEPLETION IN THE NUCLEI OF SENESCENT HUMAN FIBROBLASTS. OUR DATA REINFORCE THE HYPOTHESIS THAT PROGRESSIVE CHROMATIN DESTABILIZATION MAY LEAD TO THE LOSS OF EPIGENETIC INFORMATION AND IMPAIRED CELLULAR FUNCTION ASSOCIATED WITH CHRONIC DNA DAMAGE UPON DRUG-EVOKED SENESCENCE. WE PROPOSE THAT CHANGES IN THE HISTONE BIOSYNTHESIS AND CHROMATIN ASSEMBLY MAY DIRECTLY CONTRIBUTE TO CELLULAR AGING. IN ADDITION, WE ALSO OUTLINE THE METHOD THAT ALLOWS FOR QUANTITATIVE AND UNBIASED MEASUREMENT OF THESE CHANGES. 2012 14 4558 17 MUTATIONS IN THE NF-KAPPAB SIGNALING PATHWAY: IMPLICATIONS FOR HUMAN DISEASE. THE NUCLEAR FACTOR-KAPPA B (NF-KAPPAB) SIGNALING PATHWAY IS A MULTI-COMPONENT PATHWAY THAT REGULATES THE EXPRESSION OF HUNDREDS OF GENES THAT ARE INVOLVED IN DIVERSE AND KEY CELLULAR AND ORGANISMAL PROCESSES, INCLUDING CELL PROLIFERATION, CELL SURVIVAL, THE CELLULAR STRESS RESPONSE, INNATE IMMUNITY AND INFLAMMATION. NOT SURPRISINGLY, MIS-REGULATION OF THE NF-KAPPAB PATHWAY, EITHER BY MUTATION OR EPIGENETIC MECHANISMS, IS INVOLVED IN MANY HUMAN AND ANIMAL DISEASES, ESPECIALLY ONES ASSOCIATED WITH CHRONIC INFLAMMATION, IMMUNODEFICIENCY OR CANCER. THIS REVIEW DESCRIBES HUMAN DISEASES IN WHICH MUTATIONS IN THE COMPONENTS OF THE CORE NF-KAPPAB SIGNALING PATHWAY HAVE BEEN IMPLICATED AND DISCUSSES THE MOLECULAR MECHANISMS BY WHICH THESE ALTERATIONS IN NF-KAPPAB SIGNALING ARE LIKELY TO CONTRIBUTE TO THE DISEASE PATHOLOGY. THESE MUTATIONS CAN BE GERMLINE OR SOMATIC AND INCLUDE GENE AMPLIFICATION (E.G., REL), POINT MUTATIONS AND DELETIONS (REL, NFKB2, IKBA, CYLD, NEMO) AND CHROMOSOMAL TRANSLOCATIONS (BCL-3). IN ADDITION, HUMAN GENETIC DISEASES ARE BRIEFLY DESCRIBED WHEREIN MUTATIONS AFFECT PROTEIN MODIFIERS OR TRANSDUCERS OF NF-KAPPAB SIGNALING OR DISRUPT NF-KAPPAB-BINDING SITES IN PROMOTERS/ENHANCERS. 2006 15 3418 23 HUMAN HEALTH CONSEQUENCES OF ENVIRONMENTALLY-MODULATED GENE EXPRESSION: POTENTIAL ROLES OF ELF-EMF INDUCED EPIGENETIC VERSUS MUTAGENIC MECHANISMS OF DISEASE. IN ORDER TO DETERMINE IF THERE MIGHT BE BIOLOGICAL AND HEALTH CONSEQUENCES AFTER EXPOSURES TO EXTREMELY-LOW FREQUENCY ELECTROMAGNETIC FIELDS (ELF-EMF), EITHER EXPERIMENTALLY OR EPIDEMIOLOGICALLY, MECHANISTIC UNDERSTANDING OF THE POTENTIAL MEANS BY WHICH ANY ENVIRONMENTAL AGENT CAN AFFECT CELLS IN A MULTICELLULAR ORGANISM HAS TO BE REVIEWED. THE GOAL OF THIS LIMITED REVIEW IS TO DEMONSTRATE THAT, WHILE THE PREVAILING PARADIGM OF THE ENVIRONMENTALLY-INDUCED ACUTE AND CHRONIC DISEASES INVOLVES EITHER CELL KILLING (CYTOTOXICITY) OR GENE/CHROMOSOME MUTATIONS (GENOTOXICITY), ALTERATION OF THE EXPRESSION OF GENETIC INFORMATION AT THE TRANSCRIPTIONAL (TURNING GENES "ON" OR "OFF"), TRANSLATIONAL (STABILIZING OR DE-STABILIZING THE GENETIC MESSAGE), OR POSTTRANSLATIONAL (ALTERING THE GENE PRODUCT OR PROTEIN) LEVELS HAS THE POTENTIAL TO CONTRIBUTE TO VARIOUS DISEASES. THIS LATTER MECHANISM, "EPIGENETIC" TOXICITY, UNLIKE THE FORMER TWO WHICH ARE IRREVERSIBLE, IS CHARACTERIZED BY THRESHOLD-LIKE ACTION, MULTIPLE BIOCHEMICAL PATHWAYS AND CHRONIC, REGULAR EXPOSURES TO BE EFFECTIVE. ULTIMATELY, EPIGENETIC TOXICANTS AFFECT ONE OF FOUR POTENTIAL CELL STATES, NAMELY ALTERATION OF CELL PROLIFERATION, CELL DIFFERENTIATION, PROGRAMMED CELL DEATH (APOPTOSIS) OR ADAPTIVE RESPONSES OF DIFFERENTIATED CELLS. 2000 16 2373 19 EPIGENETIC REGULATION OF THE N-TERMINAL TRUNCATED ISOFORM OF MATRIX METALLOPROTEINASE-2 (NTT-MMP-2) AND ITS PRESENCE IN RENAL AND CARDIAC DISEASES. SEVERAL CLINICAL AND EXPERIMENTAL STUDIES HAVE DOCUMENTED A COMPELLING AND CRITICAL ROLE FOR THE FULL-LENGTH MATRIX METALLOPROTEINASE-2 (FL-MMP-2) IN ISCHEMIC RENAL INJURY, PROGRESSIVE RENAL FIBROSIS, AND DIABETIC NEPHROPATHY. A NOVEL N-TERMINAL TRUNCATED ISOFORM OF MMP-2 (NTT-MMP-2) WAS RECENTLY DISCOVERED, WHICH IS INDUCED BY HYPOXIA AND OXIDATIVE STRESS BY THE ACTIVATION OF A LATENT PROMOTER LOCATED IN THE FIRST INTRON OF THE MMP2 GENE. THIS NTT-MMP-2 ISOFORM IS ENZYMATICALLY ACTIVE BUT REMAINS INTRACELLULAR IN OR NEAR THE MITOCHONDRIA. IN THIS PERSPECTIVE ARTICLE, WE FIRST PRESENT THE FINDINGS ABOUT THE DISCOVERY OF THE NTT-MMP-2 ISOFORM, AND ITS FUNCTIONAL AND STRUCTURAL DIFFERENCES AS COMPARED WITH THE FL-MMP-2 ISOFORM. BASED ON PUBLICLY AVAILABLE EPIGENOMICS DATA FROM THE ENCYCLOPEDIA OF DNA ELEMENTS (ENCODE) PROJECT, WE PROVIDE INSIGHTS INTO THE EPIGENETIC REGULATION OF THE LATENT PROMOTER LOCATED IN THE FIRST INTRON OF THE MMP2 GENE, WHICH SUPPORT THE ACTIVATION OF THE NTT-MMP-2 ISOFORM. WE THEN FOCUS ON ITS FUNCTIONAL ASSESSMENT BY COVERING THE ALTERATIONS FOUND IN THE KIDNEY OF TRANSGENIC MICE EXPRESSING THE NTT-MMP-2 ISOFORM. NEXT, WE HIGHLIGHT RECENT FINDINGS REGARDING THE PRESENCE OF THE NTT-MMP-2 ISOFORM IN RENAL DYSFUNCTION, IN KIDNEY AND CARDIAC DISEASES, INCLUDING DAMAGE OBSERVED IN AGING, ACUTE ISCHEMIA-REPERFUSION INJURY (IRI), CHRONIC KIDNEY DISEASE, DIABETIC NEPHROPATHY, AND HUMAN RENAL TRANSPLANTS WITH DELAYED GRAFT FUNCTION. FINALLY, WE BRIEFLY DISCUSS HOW OUR INSIGHTS MAY GUIDE FURTHER EXPERIMENTAL AND CLINICAL STUDIES THAT ARE NEEDED TO ELUCIDATE THE UNDERLYING MECHANISMS AND THE ROLE OF THE NTT-MMP-2 ISOFORM IN RENAL DYSFUNCTION, WHICH MAY HELP TO ESTABLISH IT AS A POTENTIAL THERAPEUTIC TARGET IN KIDNEY DISEASES. 2021 17 5476 22 RESTORING T CELL TOLERANCE, EXPLORING THE POTENTIAL OF HISTONE DEACETYLASE INHIBITORS FOR THE TREATMENT OF JUVENILE IDIOPATHIC ARTHRITIS. JUVENILE IDIOPATHIC ARTHRITIS (JIA) IS CHARACTERIZED BY A LOSS OF IMMUNE TOLERANCE. HERE, THE BALANCE BETWEEN THE ACTIVITY OF EFFECTOR T (TEFF) CELLS AND REGULATORY T (TREG) CELLS IS DISTURBED RESULTING IN CHRONIC INFLAMMATION IN THE JOINTS. PRESENTLY, THERAPEUTIC STRATEGIES ARE PREDOMINANTLY AIMED AT SUPPRESSING IMMUNE ACTIVATION AND PRO-INFLAMMATORY EFFECTOR MECHANISMS, IGNORING THE OPPORTUNITY TO ALSO PROMOTE TOLERANCE BY BOOSTING THE REGULATORY SIDE OF THE IMMUNE BALANCE. HISTONE DEACETYLASES (HDACS) CAN DEACETYLATE BOTH HISTONE AND NON-HISTONE PROTEINS AND HAVE BEEN DEMONSTRATED TO MODULATE EPIGENETIC REGULATION AS WELL AS CELLULAR SIGNALING IN VARIOUS CELL TYPES. IMPORTANTLY, HDACS ARE POTENT REGULATORS OF BOTH TEFF CELL AND TREG CELL FUNCTION AND CAN THUS BE REGARDED AS ATTRACTIVE THERAPEUTIC TARGETS IN CHRONIC INFLAMMATORY ARTHRITIS. HDAC INHIBITORS (HDACI) HAVE PROVEN THERAPEUTIC POTENTIAL IN THE CANCER FIELD, AND ARE PRESENTLY BEING EXPLORED FOR THEIR POTENTIAL IN THE TREATMENT OF AUTOIMMUNE DISEASES. SPECIFIC HDACI HAVE ALREADY BEEN DEMONSTRATED TO REDUCE THE SECRETION OF PRO-INFLAMMATORY CYTOKINES BY TEFF CELLS, AND PROMOTE TREG NUMBERS AND SUPPRESSIVE CAPACITY IN VITRO AND IN VIVO. IN THIS REVIEW, WE OUTLINE THE ROLE OF THE DIFFERENT CLASSES OF HDACS IN BOTH TEFF CELL AND TREG CELL FUNCTION. FURTHERMORE, WE WILL REVIEW THE EFFECT OF DIFFERENT HDACI ON T CELL TOLERANCE AND EXPLORE THEIR POTENTIAL AS A THERAPEUTIC STRATEGY FOR THE TREATMENT OF OLIGOARTICULAR AND POLYARTICULAR JIA. 2019 18 6496 27 TRAINED IMMUNITY CONTRIBUTION TO AUTOIMMUNE AND INFLAMMATORY DISORDERS. A DYSREGULATED IMMUNE RESPONSE TOWARD SELF-ANTIGENS CHARACTERIZES AUTOIMMUNE AND AUTOINFLAMMATORY (AIF) DISORDERS. AUTOANTIBODIES OR AUTOREACTIVE T CELLS CONTRIBUTE TO AUTOIMMUNE DISEASES, WHILE AUTOINFLAMMATION RESULTS FROM A HYPER-FUNCTIONAL INNATE IMMUNE SYSTEM. ASIDE FROM THEIR DIFFERENCES, MANY STUDIES SUGGEST THAT MONOCYTES AND MACROPHAGES (MO/MA) SIGNIFICANTLY CONTRIBUTE TO THE DEVELOPMENT OF BOTH TYPES OF DISEASE. MO/MA ARE INNATE IMMUNE CELLS THAT PROMOTE AN IMMUNE-MODULATORY, PRO-INFLAMMATORY, OR REPAIR RESPONSE DEPENDING ON THE MICROENVIRONMENT. HOWEVER, UNDERSTANDING THE CONTRIBUTION OF THESE CELLS TO DIFFERENT IMMUNE DISORDERS HAS BEEN DIFFICULT DUE TO THEIR HIGH FUNCTIONAL AND PHENOTYPIC PLASTICITY. SEVERAL FACTORS CAN INFLUENCE THE FUNCTION OF MO/MA UNDER THE LANDSCAPE OF AUTOIMMUNE/AUTOINFLAMMATORY DISEASES, SUCH AS GENETIC PREDISPOSITION, EPIGENETIC CHANGES, OR INFECTIONS. FOR INSTANCE, SOME VACCINES AND MICROORGANISMS CAN INDUCE EPIGENETIC CHANGES IN MO/MA, MODIFYING THEIR FUNCTIONAL RESPONSES. THIS PHENOMENON IS KNOWN AS TRAINED IMMUNITY. TRAINED IMMUNITY CAN BE MEDIATED BY MO/MA AND NK CELLS INDEPENDENTLY OF T AND B CELL FUNCTION. IT IS DEFINED AS THE ALTERED INNATE IMMUNE RESPONSE TO THE SAME OR DIFFERENT MICROORGANISMS DURING A SECOND ENCOUNTER. THE IMPROVEMENT IN CELL FUNCTION IS RELATED TO EPIGENETIC AND METABOLIC CHANGES THAT MODIFY GENE EXPRESSION. ALTHOUGH THE BENEFITS OF IMMUNE TRAINING HAVE BEEN HIGHLIGHTED IN A VACCINATION CONTEXT, THE EFFECTS OF THIS TYPE OF IMMUNE RESPONSE ON AUTOIMMUNITY AND CHRONIC INFLAMMATION STILL REMAIN CONTROVERSIAL. INDUCTION OF TRAINED IMMUNITY REPROGRAMS CELLULAR METABOLISM IN HEMATOPOIETIC STEM CELLS (HSCS), TRANSMITTING A MEMORY-LIKE PHENOTYPE TO THE CELLS. THUS, TRAINED MO/MA DERIVED FROM HSCS TYPICALLY PRESENT A METABOLIC SHIFT TOWARD GLYCOLYSIS, WHICH LEADS TO THE MODIFICATION OF THE CHROMATIN ARCHITECTURE. DURING TRAINED IMMUNITY, THE EPIGENETIC CHANGES FACILITATE THE SPECIFIC GENE EXPRESSION AFTER SECONDARY CHALLENGE WITH OTHER STIMULI. CONSEQUENTLY, THE ENHANCED PRO-INFLAMMATORY RESPONSE COULD CONTRIBUTE TO DEVELOPING OR MAINTAINING AUTOIMMUNE/AUTOINFLAMMATORY DISEASES. HOWEVER, THE PREDICTION OF THE OUTCOME IS NOT SIMPLE, AND OTHER STUDIES PROPOSE THAT TRAINED IMMUNITY CAN INDUCE A BENEFICIAL RESPONSE BOTH IN AIF AND AUTOIMMUNE CONDITIONS BY INDUCING ANTI-INFLAMMATORY RESPONSES. THIS ARTICLE DESCRIBES THE METABOLIC AND EPIGENETIC MECHANISMS INVOLVED IN TRAINED IMMUNITY THAT AFFECT MO/MA, CONTRAPOSING THE CONTROVERSIAL EVIDENCE ON HOW IT MAY IMPACT AUTOIMMUNE/AUTOINFLAMMATION CONDITIONS. 2022 19 4414 17 MOLECULAR AND CELLULAR MECHANISMS OF PROPOLIS AND ITS POLYPHENOLIC COMPOUNDS AGAINST CANCER. IN RECENT YEARS, INTEREST IN NATURAL PRODUCTS SUCH AS ALTERNATIVE SOURCES OF PHARMACEUTICALS FOR NUMEROUS CHRONIC DISEASES, INCLUDING TUMORS, HAS BEEN RENEWED. PROPOLIS, A NATURAL PRODUCT COLLECTED BY HONEYBEES, AND POLYPHENOLIC/FLAVONOID PROPOLIS-RELATED COMPONENTS MODULATE ALL STEPS OF THE CANCER PROGRESSION PROCESS. ANTICANCER ACTIVITY OF PROPOLIS AND ITS COMPOUNDS RELIES ON VARIOUS MECHANISMS: CELL-CYCLE ARREST AND ATTENUATION OF CANCER CELLS PROLIFERATION, REDUCTION IN THE NUMBER OF CANCER STEM CELLS, INDUCTION OF APOPTOSIS, MODULATION OF ONCOGENE SIGNALING PATHWAYS, INHIBITION OF MATRIX METALLOPROTEINASES, PREVENTION OF METASTASIS, ANTI-ANGIOGENESIS, ANTI-INFLAMMATORY EFFECTS ACCOMPANIED BY THE MODULATION OF THE TUMOR MICROENVIRONMENT (BY MODIFYING MACROPHAGE ACTIVATION AND POLARIZATION), EPIGENETIC REGULATION, ANTIVIRAL AND BACTERICIDAL ACTIVITIES, MODULATION OF GUT MICROBIOTA, AND ATTENUATION OF CHEMOTHERAPY-INDUCED DELETERIOUS SIDE EFFECTS. INGREDIENTS FROM PROPOLIS ALSO "SENSITIZE" CANCER CELLS TO CHEMOTHERAPEUTIC AGENTS, LIKELY BY BLOCKING THE ACTIVATION OF THE TRANSCRIPTION FACTOR NUCLEAR FACTOR KAPPA-LIGHT-CHAIN-ENHANCER OF ACTIVATED B CELLS (NF-KAPPAB). IN THIS REVIEW, WE SUMMARIZE THE CURRENT KNOWLEDGE RELATED TO THE THE EFFECTS OF FLAVONOIDS AND OTHER POLYPHENOLIC COMPOUNDS FROM PROPOLIS ON TUMOR GROWTH AND METASTASIZING ABILITY, AND DISCUSS POSSIBLE MOLECULAR AND CELLULAR MECHANISMS INVOLVED IN THE MODULATION OF INFLAMMATORY PATHWAYS AND CELLULAR PROCESSES THAT AFFECT SURVIVAL, PROLIFERATION, INVASION, ANGIOGENESIS, AND METASTASIS OF THE TUMOR. 2022 20 1309 25 DEFINING AND TARGETING PATTERNS OF T CELL DYSFUNCTION IN INBORN ERRORS OF IMMUNITY. INBORN ERRORS OF IMMUNITY (IEIS) ARE A GROUP OF MORE THAN 450 MONOGENIC DISORDERS THAT IMPAIR IMMUNE DEVELOPMENT AND FUNCTION. A SUBSET OF IEIS BLEND INCREASED SUSCEPTIBILITY TO INFECTION, AUTOIMMUNITY, AND MALIGNANCY AND ARE KNOWN COLLECTIVELY AS PRIMARY IMMUNE REGULATORY DISORDERS (PIRDS). WHILE MANY ASPECTS OF IMMUNE FUNCTION ARE ALTERED IN PIRDS, ONE KEY IMPACT IS ON T-CELL FUNCTION. BY THEIR NATURE, PIRDS PROVIDE UNIQUE INSIGHTS INTO HUMAN T-CELL SIGNALING; ALTERATIONS IN INDIVIDUAL SIGNALING MOLECULES TUNE DOWNSTREAM SIGNALING PATHWAYS AND EFFECTOR FUNCTION. QUANTIFYING T-CELL DYSFUNCTION IN PIRDS AND THE UNDERLYING CAUSATIVE MECHANISMS IS CRITICAL TO IDENTIFYING EXISTING THERAPIES AND POTENTIAL NOVEL THERAPEUTIC TARGETS TO TREAT OUR RARE PATIENTS AND GAIN DEEPER INSIGHT INTO THE BASIC MECHANISMS OF T-CELL FUNCTION. THOUGH THERE ARE MANY TYPES OF T-CELL DYSFUNCTION, HERE WE WILL FOCUS ON T-CELL EXHAUSTION, A KEY PATHOPHYSIOLOGICAL STATE. EXHAUSTION HAS BEEN DESCRIBED IN BOTH HUMAN AND MOUSE MODELS OF DISEASE, WHERE THE CHRONIC PRESENCE OF ANTIGEN AND INFLAMMATION (E.G., CHRONIC INFECTION OR MALIGNANCY) INDUCES A STATE OF ALTERED IMMUNE PROFILE, TRANSCRIPTIONAL AND EPIGENETIC STATES, AS WELL AS IMPAIRED T-CELL FUNCTION. SINCE A SUBSET OF PIRDS AMPLIFY T-CELL RECEPTOR (TCR) SIGNALING AND/OR INFLAMMATORY CYTOKINE SIGNALING CASCADES, IT IS POSSIBLE THAT THEY COULD INDUCE T-CELL EXHAUSTION BY GENETICALLY MIMICKING CHRONIC INFECTION. HERE, WE REVIEW THE FUNDAMENTALS OF T-CELL EXHAUSTION AND ITS POSSIBLE ROLE IN IEIS IN WHICH GENETIC MUTATIONS MIMIC PROLONGED OR AMPLIFIED T-CELL RECEPTOR AND/OR CYTOKINE SIGNALING. GIVEN THE POTENTIAL INSIGHT FROM THE MANY FORMS OF PIRDS IN UNDERSTANDING T-CELL FUNCTION AND THE CHALLENGES IN OBTAINING PRIMARY CELLS FROM THESE RARE DISORDERS, WE ALSO DISCUSS ADVANCES IN CRISPR-CAS9 GENOME-EDITING TECHNOLOGIES AND POTENTIAL APPLICATIONS TO EDIT HEALTHY DONOR T CELLS THAT COULD FACILITATE FURTHER STUDY OF MECHANISMS OF IMMUNE DYSFUNCTIONS IN PIRDS. EDITING T CELLS TO MATCH PIRD PATIENT GENETIC VARIANTS WILL ALLOW INVESTIGATIONS INTO THE MECHANISMS UNDERPINNING STATES OF DYSREGULATED T-CELL FUNCTION, INCLUDING T-CELL EXHAUSTION. 2022