1 3171 175 GUT MICROBIAL GABAERGIC SIGNALING IMPROVES STRESS-ASSOCIATED INNATE IMMUNITY TO RESPIRATORY VIRAL INFECTION. INTRODUCTION: EPIDEMIOLOGICAL EVIDENCES REVEAL THAT POPULATIONS WITH PSYCHOLOGICAL STRESS HAVE AN INCREASED LIKELIHOOD OF RESPIRATORY VIRAL INFECTION INVOLVING INFLUENZA A VIRUS (IAV) AND SARS-COV-2. OBJECTIVES: THIS STUDY AIMS TO EXPLORE THE POTENTIAL CORRELATION BETWEEN PSYCHOLOGICAL STRESS AND INCREASED SUSCEPTIBILITY TO RESPIRATORY VIRAL INFECTIONS AND HOW THIS MAY CONTRIBUTE TO A MORE SEVERE DISEASE PROGRESSION. METHODS: A CHRONIC RESTRAINT STRESS (CRS) MOUSE MODEL WAS USED TO INFECT IAV AND ESTIMATE LUNG INFLAMMATION. ALVEOLAR MACROPHAGES (AMS) WERE OBSERVED IN THE NUMBERS, FUNCTION AND METABOLIC-EPIGENETIC PROPERTIES. TO CONFIRM THE CENTRAL IMPORTANCE OF THE GUT MICROBIOME IN STRESS-EXACERBATED VIRAL PNEUMONIA, MICE WERE CONDUCTED THROUGH MICROBIOME DEPLETION AND GUT MICROBIOME TRANSPLANTATION. RESULTS: STRESS EXPOSURE INDUCED A DECLINE IN LACTOBACILLACEAE ABUNDANCE AND HENCE GAMMA-AMINOBUTYRIC ACID (GABA) LEVEL IN MICE. MICROBIAL-DERIVED GABA WAS RELEASED IN THE PERIPHERAL AND SENSED BY AMS VIA GABA(A)R, LEADING TO ENHANCED MITOCHONDRIAL METABOLISM AND ALPHA-KETOGLUTARATE (ALPHAKG) GENERATION. THE METABOLIC INTERMEDIATOR IN TURN SERVED AS THE COFACTOR FOR THE EPIGENETIC REGULATOR TET2 TO CATALYZE DNA HYDROXYMETHYLATION AND PROMOTED THE PPARGAMMA-CENTERED GENE PROGRAM UNDERPINNING SURVIVAL, SELF-RENEWING, AND IMMUNOREGULATION OF AMS. THUS, WE UNCOVER AN UNAPPRECIATED GABA/TET2/PPARGAMMA REGULATORY CIRCUITRY INITIATED BY THE GUT MICROBIOME TO INSTRUCT DISTANT IMMUNE CELLS THROUGH A METABOLIC-EPIGENETIC PROGRAM. ACCORDINGLY, RECONSTITUTION WITH GABA-PRODUCING PROBIOTICS, ADOPTIVE TRANSFERRING OF GABA-CONDITIONED AMS, OR RESUMPTION OF PULMONARY ALPHAKG LEVEL REMARKABLY IMPROVED AMS HOMEOSTASIS AND ALLEVIATED SEVERE PNEUMONIA IN STRESSED MICE. CONCLUSION: TOGETHER, OUR STUDY IDENTIFIES MICROBIOME-DERIVED TONIC SIGNALING TUNED BY PSYCHOLOGICAL STRESS TO IMPRINT RESIDENT IMMUNE CELLS AND DEFENSIVE RESPONSE IN THE LUNGS. FURTHER STUDIES ARE WARRANTED TO TRANSLATE THESE FINDINGS, BASICALLY FROM MURINE MODELS, INTO THE INDIVIDUALS WITH PSYCHIATRIC STRESS DURING RESPIRATORY VIRAL INFECTION. 2023 2 2397 37 EPIGENETIC REPROGRAMMING OF AIRWAY MACROPHAGES PROMOTES POLARIZATION AND INFLAMMATION IN MUCO-OBSTRUCTIVE LUNG DISEASE. LUNG DISEASES, SUCH AS CYSTIC FIBROSIS AND COPD, ARE CHARACTERIZED BY MUCUS OBSTRUCTION AND CHRONIC AIRWAY INFLAMMATION, BUT THEIR MECHANISTIC LINK REMAINS POORLY UNDERSTOOD. HERE, WE FOCUS ON THE FUNCTION OF THE MUCOSTATIC AIRWAY MICROENVIRONMENT ON EPIGENETIC REPROGRAMMING OF AIRWAY MACROPHAGES (AM) AND RESULTING TRANSCRIPTOMIC AND PHENOTYPICAL CHANGES. USING A MOUSE MODEL OF MUCO-OBSTRUCTIVE LUNG DISEASE (SCNN1B-TRANSGENIC), WE IDENTIFY EPIGENETICALLY CONTROLLED, DIFFERENTIALLY REGULATED PATHWAYS AND TRANSCRIPTION FACTORS INVOLVED IN INFLAMMATORY RESPONSES AND MACROPHAGE POLARIZATION. FUNCTIONALLY, AMS FROM SCNN1B-TRANSGENIC MICE HAVE REDUCED EFFEROCYTOSIS AND PHAGOCYTOSIS, AND EXCESSIVE INFLAMMATORY RESPONSES UPON LIPOPOLYSACCHARIDE CHALLENGE, MEDIATED THROUGH ENHANCED IRF1 FUNCTION AND EXPRESSION. EX VIVO STIMULATION OF WILD-TYPE AMS WITH NATIVE MUCUS IMPAIRS EFFEROCYTOSIS AND PHAGOCYTOSIS CAPACITIES. IN ADDITION, MUCUS INDUCES GENE EXPRESSION CHANGES, COMPARABLE WITH THOSE OBSERVED IN AMS FROM SCNN1B-TRANSGENIC MICE. OUR DATA SHOW THAT MUCOSTASIS INDUCES EPIGENETIC REPROGRAMMING OF AMS, LEADING TO CHANGES FAVORING TISSUE DAMAGE AND DISEASE PROGRESSION. TARGETING THESE ALTERED AMS MAY SUPPORT THERAPEUTIC APPROACHES IN PATIENTS WITH MUCO-OBSTRUCTIVE LUNG DISEASES. 2021 3 2671 40 ETHANOL CONSUMPTION INDUCES NONSPECIFIC INFLAMMATION AND FUNCTIONAL DEFECTS IN ALVEOLAR MACROPHAGES. CHRONIC ALCOHOL DRINKING IS ASSOCIATED WITH INCREASED SUSCEPTIBILITY TO VIRAL AND BACTERIAL RESPIRATORY PATHOGENS. IN THIS STUDY, WE USE A RHESUS MACAQUE MODEL OF VOLUNTARY ETHANOL SELF-ADMINISTRATION TO STUDY THE EFFECTS OF LONG-TERM ALCOHOL DRINKING ON THE IMMUNOLOGICAL LANDSCAPE OF THE LUNG. WE REPORT A HEIGHTENED INFLAMMATORY STATE IN ALVEOLAR MACROPHAGES (AMS) OBTAINED FROM ETHANOL (ETOH)-DRINKING ANIMALS THAT IS ACCOMPANIED BY INCREASED CHROMATIN ACCESSIBILITY IN INTERGENIC REGIONS THAT REGULATE INFLAMMATORY GENES AND CONTAIN BINDING MOTIFS FOR TRANSCRIPTION FACTORS AP-1, IRF8, AND NFKB P-65. IN LINE WITH THESE TRANSCRIPTIONAL AND EPIGENETIC CHANGES AT THE BASAL STATE, AMS FROM ETOH-DRINKING ANIMALS GENERATE ELEVATED INFLAMMATORY MEDIATOR RESPONSES TO LIPOPOLYSACCHARIDES AND RESPIRATORY SYNCYTIAL VIRUS. HOWEVER, THE TRANSCRIPTIONAL ANALYSIS REVEALED AN INEFFICIENT INDUCTION OF INTERFERON-STIMULATED GENES WITH ETOH IN RESPONSE TO THE RESPIRATORY SYNCYTIAL VIRUS, SUGGESTING DISRUPTION OF ANTIMICROBIAL DEFENSES. CORRESPONDINGLY, AMS FROM ETOH-DRINKING ANIMALS EXHIBITED TRANSCRIPTIONAL SHIFTS INDICATIVE OF INCREASED OXIDATIVE STRESS AND OXIDATIVE PHOSPHORYLATION, WHICH WAS COUPLED WITH HIGHER CYTOSOLIC REACTIVE OXYGEN SPECIES AND MITOCHONDRIAL POTENTIAL. THIS HEIGHTENED OXIDATIVE STRESS STATE WAS ACCOMPANIED BY DECREASED ABILITY TO PHAGOCYTOSE BACTERIA. BULK RNA AND ASSAY FOR TRANSPOSASE-ACCESSIBLE CHROMATIN SEQUENCING DATA FURTHER REVEALED REDUCED EXPRESSION AND CHROMATIN ACCESSIBILITY OF LOCI ASSOCIATED WITH TISSUE REPAIR AND MAINTENANCE WITH CHRONIC ETOH DRINKING. SIMILARLY, ANALYSIS OF SINGLE-CELL RNA SEQUENCING DATA REVEALED SHIFTS IN CELL STATES FROM TISSUE MAINTENANCE TO INFLAMMATORY RESPONSES WITH ETOH. COLLECTIVELY, THESE DATA PROVIDE NOVEL INSIGHT INTO MECHANISMS BY WHICH CHRONIC ETOH DRINKING INCREASES SUSCEPTIBILITY TO INFECTION IN PATIENTS WITH ALCOHOL USE DISORDERS. 2022 4 4039 43 MACROPHAGE NOX2 NADPH OXIDASE MAINTAINS ALVEOLAR HOMEOSTASIS IN MICE. THE LEUKOCYTE NADPH OXIDASE 2 (NOX2) PLAYS A KEY ROLE IN PATHOGEN KILLING AND IMMUNOREGULATION. GENETIC DEFECTS IN NOX2 RESULT IN CHRONIC GRANULOMATOUS DISEASE (CGD), ASSOCIATED WITH MICROBIAL INFECTIONS AND INFLAMMATORY DISORDERS, OFTEN INVOLVING THE LUNG. ALVEOLAR MACROPHAGES (AMS) ARE THE PREDOMINANT IMMUNE CELL IN THE AIRWAYS AT STEADY STATE, AND LIMITING THEIR ACTIVATION IS IMPORTANT, GIVEN THE CONSTANT EXPOSURE TO INHALED MATERIALS, YET THE IMPORTANCE OF NOX2 IN THIS PROCESS IS NOT WELL UNDERSTOOD. IN THIS STUDY, WE SHOWED A PREVIOUSLY UNDESCRIBED ROLE FOR NOX2 IN MAINTAINING LUNG HOMEOSTASIS BY SUPPRESSING AM ACTIVATION, IN CGD MICE OR MICE WITH SELECTIVE LOSS OF NOX2 PREFERENTIALLY IN MACROPHAGES. AMS LACKING NOX2 HAD INCREASED CYTOKINE RESPONSES TO TOLL-LIKE RECEPTOR-2 (TLR2) AND TLR4 STIMULATION EX VIVO. MOREOVER, BETWEEN 4 AND 12 WEEK OF AGE, MICE WITH GLOBAL NOX2 DELETION DEVELOPED AN ACTIVATED CD11BHIGH SUBSET OF AMS WITH EPIGENETIC AND TRANSCRIPTIONAL PROFILES REFLECTING IMMUNE ACTIVATION COMPARED WITH WT AMS. THE PRESENCE OF CD11BHIGH AMS IN CGD MICE CORRELATED WITH AN INCREASED NUMBER OF ALVEOLAR NEUTROPHILS AND PROINFLAMMATORY CYTOKINES AT STEADY STATE AND INCREASED LUNG INFLAMMATION AFTER INSULTS. MOREOVER, DELETION OF NOX2 PREFERENTIALLY IN MACROPHAGES WAS SUFFICIENT FOR MICE TO DEVELOP AN ACTIVATED CD11BHIGH AM SUBSET AND ACCOMPANYING PROINFLAMMATORY SEQUELAE. IN ADDITION, WE SHOWED THAT THE ALTERED RESIDENT MACROPHAGE TRANSCRIPTIONAL PROFILE IN THE ABSENCE OF NOX2 IS TISSUE SPECIFIC, AS THOSE CHANGES WERE NOT SEEN IN RESIDENT PERITONEAL MACROPHAGES. THUS, THESE DATA DEMONSTRATE THAT THE ABSENCE OF NOX2 IN ALVEOLAR MACROPHAGES LEADS TO THEIR PROINFLAMMATORY REMODELING AND DYSREGULATES ALVEOLAR HOMEOSTASIS. 2022 5 3760 26 INTEGRATED SINGLE CELL ANALYSIS SHOWS CHRONIC ALCOHOL DRINKING DISRUPTS MONOCYTE DIFFERENTIATION IN THE BONE MARROW. CHRONIC HEAVY ALCOHOL DRINKING (CHD) REWIRES MONOCYTES AND MACROPHAGES TOWARD HEIGHTENED INFLAMMATORY STATES WITH COMPROMISED ANTIMICROBIAL DEFENSES THAT PERSIST AFTER 1-MONTH ABSTINENCE. TO DETERMINE WHETHER THESE CHANGES ARE MEDIATED THROUGH ALTERATIONS IN THE BONE MARROW NICHE, WE PROFILED MONOCYTES AND HEMATOPOIETIC STEM CELL PROGENITORS (HSCPS) FROM CHD RHESUS MACAQUES USING A COMBINATION OF FUNCTIONAL ASSAYS AND SINGLE CELL GENOMICS. CHD RESULTED IN TRANSCRIPTIONAL PROFILES CONSISTENT WITH INCREASED ACTIVATION AND INFLAMMATION WITHIN BONE MARROW RESIDENT MONOCYTES AND MACROPHAGES. FURTHERMORE, CHD RESULTED IN TRANSCRIPTIONAL SIGNATURES ASSOCIATED WITH INCREASED OXIDATIVE AND CELLULAR STRESS IN HSCP. DIFFERENTIATION OF HSCP IN VITRO REVEALED SKEWING TOWARD MONOCYTES EXPRESSING "NEUTROPHIL-LIKE" MARKERS WITH GREATER INFLAMMATORY RESPONSES TO BACTERIAL AGONISTS. FURTHER ANALYSES OF HSCPS SHOWED BROAD EPIGENETIC CHANGES THAT WERE IN LINE WITH EXACERBATED INFLAMMATORY RESPONSES WITHIN MONOCYTES AND THEIR PROGENITORS. IN SUMMARY, CHD ALTERS HSCPS IN THE BONE MARROW LEADING TO THE PRODUCTION OF MONOCYTES POISED TO GENERATE DYSREGULATED HYPER-INFLAMMATORY RESPONSES. 2023 6 6540 38 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 7 5425 29 REGULATION OF MYELOPOIESIS BY THE TRANSCRIPTION FACTOR IRF8. INTERFERON REGULATORY FACTOR-8 (IRF8) IS A TRANSCRIPTION FACTOR EXPRESSED IN HEMATOPOIETIC CELLS, PARTICULARLY IN MONONUCLEAR PHAGOCYTES [MONOCYTES/MACROPHAGES AND DENDRITIC CELLS (DCS)] AND THEIR PROGENITORS. VARIOUS STUDIES HAVE DEMONSTRATED THAT IRF8 IS ESSENTIAL FOR THE DEVELOPMENT OF MONOCYTES, DCS, EOSINOPHILS, AND BASOPHILS. CONVERSELY, IRF8 SUPPRESSES THE GENERATION OF NEUTROPHILS. ACCORDINGLY, IRF8 (-/-) MICE DEVELOP IMMUNODEFICIENCY AND A CHRONIC MYELOID LEUKEMIA (CML)-LIKE DISEASE. MUTATIONS AND LOSS OF EXPRESSION OF THE HUMAN IRF8 GENE ARE ALSO ASSOCIATED WITH IMMUNODEFICIENCY AND CML, RESPECTIVELY. RECENT FINDINGS HAVE BEGUN TO REVEAL THE TRANSCRIPTION FACTOR NETWORK AND EPIGENETIC CHANGES GOVERNED BY IRF8. FOR EXAMPLE, IN MONONUCLEAR PHAGOCYTE PROGENITORS, IRF8 COOPERATES WITH PU.1 TO PROMOTE THE FORMATION OF PROMOTER-DISTAL ENHANCERS TO INDUCE MONOCYTE-RELATED GENES INCLUDING THE CRITICAL DOWNSTREAM TRANSCRIPTION FACTOR GENE KLF4. ON THE OTHER HAND, IRF8 BLOCKS C/EBPALPHA ACTIVITY TO SUPPRESS THE NEUTROPHIL DIFFERENTIATION PROGRAM. INDEED, IRF8 (-/-) MONONUCLEAR PHAGOCYTE PROGENITORS FAIL TO EFFICIENTLY GENERATE MONOCYTES AND DCS AND, INSTEAD, ABERRANTLY GIVE RISE TO NEUTROPHILS. THIS ARTICLE PROVIDES AN OVERVIEW OF RECENT ADVANCES IN OUR UNDERSTANDING OF THE ROLE OF IRF8 IN MYELOPOIESIS AND RELATED DISEASES. 2015 8 3759 28 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 9 4116 41 MECHANISMS OF AIRWAY EPITHELIAL INJURY AND ABNORMAL REPAIR IN ASTHMA AND COPD. THE AIRWAY EPITHELIUM COMPRISES OF DIFFERENT CELL TYPES AND ACTS AS A PHYSICAL BARRIER PREVENTING PATHOGENS, INCLUDING INHALED PARTICLES AND MICROBES, FROM ENTERING THE LUNGS. GOBLET CELLS AND SUBMUCOSAL GLANDS PRODUCE MUCUS THAT TRAPS PATHOGENS, WHICH ARE EXPELLED FROM THE RESPIRATORY TRACT BY CILIATED CELLS. BASAL CELLS ACT AS PROGENITOR CELLS, DIFFERENTIATING INTO DIFFERENT EPITHELIAL CELL TYPES, TO MAINTAIN HOMEOSTASIS FOLLOWING INJURY. ADHERENS AND TIGHT JUNCTIONS BETWEEN CELLS MAINTAIN THE EPITHELIAL BARRIER FUNCTION AND REGULATE THE MOVEMENT OF MOLECULES ACROSS IT. IN THIS REVIEW WE DISCUSS HOW ABNORMAL EPITHELIAL STRUCTURE AND FUNCTION, CAUSED BY CHRONIC INJURY AND ABNORMAL REPAIR, DRIVES AIRWAY DISEASE AND SPECIFICALLY ASTHMA AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). IN BOTH DISEASES, INHALED ALLERGENS, POLLUTANTS AND MICROBES DISRUPT JUNCTIONAL COMPLEXES AND PROMOTE CELL DEATH, IMPAIRING THE BARRIER FUNCTION AND LEADING TO INCREASED PENETRATION OF PATHOGENS AND A CONSTANT AIRWAY IMMUNE RESPONSE. IN ASTHMA, THE INFLAMMATORY RESPONSE PRECIPITATES THE EPITHELIAL INJURY AND DRIVES ABNORMAL BASAL CELL DIFFERENTIATION. THIS LEADS TO REDUCED CILIATED CELLS, GOBLET CELL HYPERPLASIA AND INCREASED EPITHELIAL MESENCHYMAL TRANSITION, WHICH CONTRIBUTE TO IMPAIRED MUCOCILIARY CLEARANCE AND AIRWAY REMODELLING. IN COPD, CHRONIC OXIDATIVE STRESS AND INFLAMMATION TRIGGER PREMATURE EPITHELIAL CELL SENESCENCE, WHICH CONTRIBUTES TO LOSS OF EPITHELIAL INTEGRITY AND AIRWAY INFLAMMATION AND REMODELLING. INCREASED NUMBERS OF BASAL CELLS SHOWING DEREGULATED DIFFERENTIATION, CONTRIBUTES TO CILIARY DYSFUNCTION AND MUCOUS HYPERPRODUCTION IN COPD AIRWAYS. DEFECTIVE ANTIOXIDANT, ANTIVIRAL AND DAMAGE REPAIR MECHANISMS, POSSIBLY DUE TO GENETIC OR EPIGENETIC FACTORS, MAY CONFER SUSCEPTIBILITY TO AIRWAY EPITHELIAL DYSFUNCTION IN THESE DISEASES. THE CURRENT EVIDENCE SUGGESTS THAT A CONSTANT CYCLE OF INJURY AND ABNORMAL REPAIR OF THE EPITHELIUM DRIVES CHRONIC AIRWAY INFLAMMATION AND REMODELLING IN ASTHMA AND COPD. MECHANISTIC UNDERSTANDING OF INJURY SUSCEPTIBILITY AND DAMAGE RESPONSE MAY LEAD TO IMPROVED THERAPIES FOR THESE DISEASES. 2023 10 329 35 ALPHA-OXOGLUTARATE INHIBITS THE PROLIFERATION OF IMMORTALIZED NORMAL BLADDER EPITHELIAL CELLS VIA AN EPIGENETIC SWITCH INVOLVING ARID1A. INTERSTITIAL CYSTITIS (IC) IS A CHRONIC URINARY TRACT DISEASE THAT IS CHARACTERIZED BY UNPLEASANT SENSATIONS, SUCH AS PERSISTENT PELVIC PAIN, IN THE ABSENCE OF INFECTION OR OTHER IDENTIFIABLE CAUSES. WE PREVIOUSLY PERFORMED COMPREHENSIVE METABOLOMICS PROFILING OF URINE SAMPLES FROM IC PATIENTS USING NUCLEAR MAGNETIC RESONANCE AND GAS-CHROMATOGRAPHY/MASS SPECTROMETRY AND FOUND THAT URINARY ALPHA-OXOGLUTARATE (ALPHA-OG), WAS SIGNIFICANTLY ELEVATED. ALPHA-OG, A TRICARBOXYLIC ACID (TCA) CYCLE INTERMEDIATE, REPORTEDLY FUNCTIONS TO SUPPRESS THE PROLIFERATION OF IMMORTALIZED NORMAL HUMAN BLADDER EPITHELIAL CELLS. HERE, WE IDENTIFIED AT-RICH INTERACTIVE DOMAIN 1 A (ARID1A), A KEY CHROMATIN REMODELER, AS BEING HYPOMETHYLATED AND UPREGULATED BY ALPHA-OG TREATMENT. THIS WAS DONE THROUGH EPIC DNA METHYLATION PROFILING AND SUBSEQUENT BIOCHEMICAL APPROACHES, INCLUDING QUANTITATIVE RT-PCR AND WESTERN BLOT ANALYSES. FURTHERMORE, WE FOUND THAT ALPHA-OG ALMOST COMPLETELY SUPPRESSES TEN-ELEVEN TRANSLOCATION (TET) ACTIVITY, BUT DOES NOT AFFECT DNA METHYLTRANSFERASE (DNMT) ACTIVITY. ALTOGETHER, OUR STUDIES REVEAL THE POTENTIAL ROLE OF ALPHA-OG IN EPIGENETIC REMODELING THROUGH ITS EFFECTS ON ARID1A AND TET EXPRESSION IN THE BLADDER. THIS MAY PROVIDE A NEW POSSIBLE THERAPEUTIC STRATEGY IN TREATING IC. 2018 11 4563 39 MYELOID DNA METHYLTRANSFERASE3B DEFICIENCY AGGRAVATES PULMONARY FIBROSIS BY ENHANCING PROFIBROTIC MACROPHAGE ACTIVATION. BACKGROUND: IDIOPATHIC PULMONARY FIBROSIS (IPF) IS A CHRONIC, PROGRESSIVE AND SEVERE DISEASE CHARACTERIZED BY EXCESSIVE MATRIX DEPOSITION IN THE LUNGS. MACROPHAGES PLAY CRUCIAL ROLES IN MAINTAINING LUNG HOMEOSTASIS BUT ARE ALSO CENTRAL IN THE PATHOGENESIS OF LUNG DISEASES LIKE PULMONARY FIBROSIS. ESPECIALLY, MACROPHAGE POLARIZATION/ACTIVATION SEEMS TO PLAY A CRUCIAL ROLE IN PATHOLOGY AND EPIGENETIC REPROGRAMING IS WELL-KNOWN TO REGULATE MACROPHAGE POLARIZATION. DNA METHYLATION ALTERATIONS IN IPF LUNGS HAVE BEEN WELL DOCUMENTED, BUT THE ROLE OF DNA METHYLATION IN SPECIFIC CELL TYPES, ESPECIALLY MACROPHAGES, IS POORLY DEFINED. METHODS: IN ORDER TO DETERMINE THE ROLE OF DNA METHYLATION IN MACROPHAGES DURING PULMONARY FIBROSIS, WE SUBJECTED MACROPHAGE SPECIFIC DNA METHYLTRANSFERASE (DNMT)3B, WHICH MEDIATES THE DE NOVO DNA METHYLATION, DEFICIENT MICE TO THE BLEOMYCIN-INDUCED PULMONARY FIBROSIS MODEL. MACROPHAGE POLARIZATION AND FIBROTIC PARAMETERS WERE EVALUATED AT 21 DAYS AFTER BLEOMYCIN ADMINISTRATION. DNMT3B KNOCKOUT AND WILD TYPE BONE MARROW-DERIVED MACROPHAGES WERE STIMULATED WITH EITHER INTERLEUKIN (IL)4 OR TRANSFORMING GROWTH FACTOR BETA 1 (TGFB1) IN VITRO, AFTER WHICH PROFIBROTIC GENE EXPRESSION AND DNA METHYLATION AT THE ARG1 PROMOTOR WERE DETERMINED. RESULTS: WE SHOW THAT DNMT3B DEFICIENCY PROMOTES ALTERNATIVE MACROPHAGE POLARIZATION INDUCED BY IL4 AND TGFB1 IN VITRO AND ALSO ENHANCES PROFIBROTIC MACROPHAGE POLARIZATION IN THE ALVEOLAR SPACE DURING PULMONARY FIBROSIS IN VIVO. MOREOVER, MYELOID SPECIFIC DELETION OF DNMT3B PROMOTED THE DEVELOPMENT OF EXPERIMENTAL PULMONARY FIBROSIS. CONCLUSIONS: IN SUMMARY, THESE DATA SUGGEST THAT MYELOID DNMT3B REPRESSES FIBROTIC MACROPHAGE POLARIZATION AND PROTECTS AGAINST BLEOMYCIN INDUCED PULMONARY FIBROSIS. 2022 12 2241 30 EPIGENETIC MODULATION IN PERIODONTITIS: INTERACTION OF ADIPONECTIN AND JMJD3-IRF4 AXIS IN MACROPHAGES. EMERGING EVIDENCE SUGGESTS AN IMPORTANT ROLE FOR EPIGENETIC MECHANISMS IN MODULATING SIGNALS DURING MACROPHAGE POLARIZATION AND INFLAMMATION. JMJD3, A JMJC FAMILY HISTONE DEMETHYLASE NECESSARY FOR M2 POLARIZATION IS ALSO REQUIRED FOR EFFECTIVE INDUCTION OF MULTIPLE M1 GENES BY LIPOPOLYSACCHARIDE (LPS). HOWEVER, THE EFFECTS OF JMJD3 TO INFLAMMATION IN THE CONTEXT OF OBESITY REMAINS UNKNOWN. TO ADDRESS THIS DEFICIENCY, WE FIRSTLY EXAMINED THE EXPRESSION OF JMJD3 IN MACROPHAGE ISOLATED FROM BONE MARROW AND ADIPOSE TISSUE OF DIET INDUCED OBESITY (DIO) MICE. THE RESULTS INDICATED THAT JMJD3 WAS DOWN-REGULATED IN OBESITY. ADIPONECTIN (APN), A FACTOR SECRETED BY ADIPOSE TISSUE WHICH IS DOWN-REGULATED IN OBESITY, FUNCTIONS TO SWITCH MACROPHAGE POLARIZATION FROM M1 TO M2, THEREBY ATTENUATING CHRONIC INFLAMMATION. INTRIGUINGLY, OUR RESULTS INDICATED THAT APN CONTRIBUTED TO JMJD3 UP-REGULATION, REDUCED MACROPHAGE INFILTRATION IN OBESE ADIPOSE TISSUE, AND ABOLISHED THE UP-REGULATION OF JMJD3 IN PERITONEAL MACROPHAGES ISOLATED FROM DIO MICE WHEN CHALLENGED WITH PORPHYROMONAS GINGIVALIS LPS (PG.LPS). TO ELUCIDATE THE INTERACTION OF APN AND JMJD3 INVOLVED IN MACROPHAGE TRANSFORMATION IN THE CONTEXT OF INFLAMMATION, WE DESIGNED THE LOSS AND GAIN-FUNCTION EXPERIMENTS OF APN IN VIVO WITH APN(-/-) MICE WITH EXPERIMENTAL PERIODONTITIS AND IN VITRO WITH MACROPHAGE ISOLATED FROM APN(-/-) MICE. FOR THE FIRST TIME, WE FOUND THAT APN CAN HELP TO REDUCE PERIODONTITIS-RELATED BONE LOSS, MODULATE JMJD3 AND IRF4 EXPRESSION, AND MACROPHAGE INFILTRATION. THEREFORE, IT CAN BE INFERRED THAT APN MAY CONTRIBUTE TO ANTI-INFLAMMATION MACROPHAGE POLARIZATION BY REGULATING JMJD3 EXPRESSION, WHICH PROVIDES A BASIS FOR MACROPHAGE-CENTERED EPIGENETIC THERAPEUTIC STRATEGIES. 2016 13 4506 28 MRTF-A MEDIATES LPS-INDUCED PRO-INFLAMMATORY TRANSCRIPTION BY INTERACTING WITH THE COMPASS COMPLEX. CHRONIC INFLAMMATION UNDERSCORES THE PATHOGENESIS OF A RANGE OF HUMAN DISEASES. LIPOPOLYSACCHARIDE (LPS) ELICITS STRONG PRO-INFLAMMATORY RESPONSES IN MACROPHAGES THROUGH THE TRANSCRIPTION FACTOR NF-KAPPAB. THE EPIGENETIC MECHANISM UNDERLYING LPS-INDUCED PRO-INFLAMMATORY TRANSCRIPTION IS NOT FULLY UNDERSTOOD. HEREIN, WE DESCRIBE A ROLE FOR MYOCARDIN-RELATED TRANSCRIPTION FACTOR A (MRTF-A, ALSO KNOWN AS MKL1) IN THIS PROCESS. MRTF-A OVEREXPRESSION ENHANCED NF-KAPPAB-DEPENDENT PRO-INFLAMMATORY TRANSCRIPTION, WHEREAS MRTF-A SILENCING INHIBITED THIS PROCESS. MRTF-A DEFICIENCY ALSO REDUCED THE SYNTHESIS OF PRO-INFLAMMATORY MEDIATORS IN A MOUSE MODEL OF COLITIS. LPS PROMOTED THE RECRUITMENT OF MRTF-A TO THE PROMOTERS OF PRO-INFLAMMATORY GENES IN AN NF-KAPPAB-DEPENDENT MANNER. RECIPROCALLY, MRTF-A INFLUENCED THE NUCLEAR ENRICHMENT AND TARGET BINDING OF NF-KAPPAB. MECHANISTICALLY, MRTF-A WAS NECESSARY FOR THE ACCUMULATION OF ACTIVE HISTONE MODIFICATIONS ON NF-KAPPAB TARGET PROMOTERS BY COMMUNICATING WITH THE HISTONE H3K4 METHYLTRANSFERASE COMPLEX (COMPASS). SILENCING OF INDIVIDUAL MEMBERS OF COMPASS, INCLUDING ASH2, WDR5 AND SET1 (ALSO KNOWN AS SETD1A), DOWNREGULATED THE PRODUCTION OF PRO-INFLAMMATORY MEDIATORS AND IMPAIRED THE NF-KAPPAB KINETICS. IN SUMMARY, OUR WORK HAS UNCOVERED A PREVIOUSLY UNKNOWN FUNCTION FOR MRTF-A AND PROVIDED INSIGHTS INTO THE RATIONALIZED DEVELOPMENT OF ANTI-INFLAMMATORY THERAPEUTIC STRATEGIES. 2014 14 2067 33 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 15 987 35 CHRONIC SCHISTOSOMIASIS DURING PREGNANCY EPIGENETICALLY REPROGRAMS T-CELL DIFFERENTIATION IN OFFSPRING OF INFECTED MOTHERS. SCHISTOSOMIASIS IS A NONTRANSPLACENTAL HELMINTH INFECTION. CHRONIC INFECTION DURING PREGNANCY SUPPRESSES ALLERGIC AIRWAY RESPONSES IN OFFSPRING. WE ADDRESSED THE QUESTION WHETHER IN UTERO EXPOSURE TO CHRONIC SCHISTOSOME INFECTION (REG PHASE) IN MICE AFFECTS B-CELL AND T-CELL DEVELOPMENT. THEREFORE, WE FOCUSED OUR ANALYSES ON T-CELL DIFFERENTIATION CAPACITY INDUCED BY EPIGENETIC CHANGES IN PROMOTER REGIONS OF SIGNATURE CYTOKINES IN OFFSPRING. HERE, WE SHOW THAT NAIVE T CELLS FROM OFFSPRING OF SCHISTOSOME INFECTED FEMALE MICE HAD A STRONG CAPACITY TO DIFFERENTIATE INTO T(H) 1 CELLS, WHEREAS T(H) 2 DIFFERENTIATION WAS IMPAIRED. IN ACCORDANCE, REDUCED LEVELS OF HISTONE ACETYLATION OF THE IL-4 PROMOTER REGIONS WERE OBSERVED IN NAIVE T CELLS. TO CONCLUDE, OUR MOUSE MODEL REVEALED DISTINCT EPIGENETIC CHANGES WITHIN THE NAIVE T-CELL COMPARTMENT AFFECTING T(H) 2 AND T(H) 1 CELL DIFFERENTIATION IN OFFSPRING OF MOTHERS WITH CHRONIC HELMINTH INFECTION. THESE FINDINGS COULD EVENTUALLY HELP UNDERSTAND HOW HELMINTHS ALTER T-CELL DRIVEN IMMUNE RESPONSES INDUCED BY ALLERGENS, BACTERIAL OR VIRAL INFECTIONS, AS WELL AS VACCINES. 2017 16 3616 28 IN VITRO MODELING OF CD8 T CELL EXHAUSTION ENABLES CRISPR SCREENING TO REVEAL A ROLE FOR BHLHE40. IDENTIFYING NOVEL MOLECULAR MECHANISMS OF EXHAUSTED CD8 T CELLS (T (EX) ) IS A KEY GOAL OF IMPROVING IMMUNOTHERAPY OF CANCER AND OTHER DISEASES. HOWEVER, HIGH-THROUGHPUT INTERROGATION OF IN VIVO T (EX) CAN BE COSTLY AND INEFFICIENT. IN VITRO MODELS OF T (EX) ARE EASILY CUSTOMIZABLE AND QUICKLY GENERATE HIGH CELLULAR YIELD, OFFERING AN OPPORTUNITY TO PERFORM CRISPR SCREENING AND OTHER HIGH-THROUGHPUT ASSAYS. WE ESTABLISHED AN IN VITRO MODEL OF CHRONIC STIMULATION AND BENCHMARKED KEY PHENOTYPIC, FUNCTIONAL, TRANSCRIPTIONAL, AND EPIGENETIC FEATURES AGAINST BONA FIDE IN VIVO T (EX) . WE LEVERAGED THIS MODEL OF IN VITRO CHRONIC STIMULATION IN COMBINATION WITH POOLED CRISPR SCREENING TO UNCOVER TRANSCRIPTIONAL REGULATORS OF T CELL EXHAUSTION. THIS APPROACH IDENTIFIED SEVERAL TRANSCRIPTION FACTORS, INCLUDING BHLHE40. IN VITRO AND IN VIVO VALIDATION DEFINED A ROLE FOR BHLHE40 IN REGULATING A KEY DIFFERENTIATION CHECKPOINT BETWEEN PROGENITOR AND INTERMEDIATE SUBSETS OF T (EX) . BY DEVELOPING AND BENCHMARKING AN IN VITRO MODEL OF T (EX) , WE DEMONSTRATE THE UTILITY OF MECHANISTICALLY ANNOTATED IN VITRO MODELS OF T (EX) , IN COMBINATION WITH HIGH-THROUGHPUT APPROACHES, AS A DISCOVERY PIPELINE TO UNCOVER NOVEL T (EX) BIOLOGY. 2023 17 3359 25 HISTONE H4 LYSINE 16 ACETYLATION CONTROLS CENTRAL CARBON METABOLISM AND DIET-INDUCED OBESITY IN MICE. NONCOMMUNICABLE DISEASES (NCDS) ACCOUNT FOR OVER 70% OF DEATHS WORLD-WIDE. PREVIOUS WORK HAS LINKED NCDS SUCH AS TYPE 2 DIABETES (T2D) TO DISRUPTION OF CHROMATIN REGULATORS. HOWEVER, THE EXACT MOLECULAR ORIGINS OF THESE CHRONIC CONDITIONS REMAIN ELUSIVE. HERE, WE IDENTIFY THE H4 LYSINE 16 ACETYLTRANSFERASE MOF AS A CRITICAL REGULATOR OF CENTRAL CARBON METABOLISM. HIGH-THROUGHPUT METABOLOMICS UNVEIL A SYSTEMIC AMINO ACID AND CARBOHYDRATE IMBALANCE IN MOF DEFICIENT MICE, MANIFESTING IN T2D PREDISPOSITION. ORAL GLUCOSE TOLERANCE TESTING (OGTT) REVEALS DEFECTS IN GLUCOSE ASSIMILATION AND INSULIN SECRETION IN THESE ANIMALS. FURTHERMORE, MOF DEFICIENT MICE ARE RESISTANT TO DIET-INDUCED FAT GAIN DUE TO DEFECTS IN GLUCOSE UPTAKE IN ADIPOSE TISSUE. MOF-MEDIATED H4K16AC DEPOSITION CONTROLS EXPRESSION OF THE MASTER REGULATOR OF GLUCOSE METABOLISM, PPARG AND THE ENTIRE DOWNSTREAM TRANSCRIPTIONAL NETWORK. GLUCOSE UPTAKE AND LIPID STORAGE CAN BE RECONSTITUTED IN MOF-DEPLETED ADIPOCYTES IN VITRO BY ECTOPIC GLUT4 EXPRESSION, PPARGAMMA AGONIST THIAZOLIDINEDIONE (TZD) TREATMENT OR SIRT1 INHIBITION. HENCE, CHRONIC IMBALANCE IN H4K16AC PROMOTES A DESTABILISATION OF METABOLISM TRIGGERING THE DEVELOPMENT OF A METABOLIC DISORDER, AND ITS MAINTENANCE PROVIDES AN UNPRECEDENTED REGULATORY EPIGENETIC MECHANISM CONTROLLING DIET-INDUCED OBESITY. 2021 18 4040 23 MACROPHAGE PLASTICITY AND POLARIZATION: IN VIVO VERITAS. DIVERSITY AND PLASTICITY ARE HALLMARKS OF CELLS OF THE MONOCYTE-MACROPHAGE LINEAGE. IN RESPONSE TO IFNS, TOLL-LIKE RECEPTOR ENGAGEMENT, OR IL-4/IL-13 SIGNALING, MACROPHAGES UNDERGO M1 (CLASSICAL) OR M2 (ALTERNATIVE) ACTIVATION, WHICH REPRESENT EXTREMES OF A CONTINUUM IN A UNIVERSE OF ACTIVATION STATES. PROGRESS HAS NOW BEEN MADE IN DEFINING THE SIGNALING PATHWAYS, TRANSCRIPTIONAL NETWORKS, AND EPIGENETIC MECHANISMS UNDERLYING M1-M2 OR M2-LIKE POLARIZED ACTIVATION. FUNCTIONAL SKEWING OF MONONUCLEAR PHAGOCYTES OCCURS IN VIVO UNDER PHYSIOLOGICAL CONDITIONS (E.G., ONTOGENESIS AND PREGNANCY) AND IN PATHOLOGY (ALLERGIC AND CHRONIC INFLAMMATION, TISSUE REPAIR, INFECTION, AND CANCER). HOWEVER, IN SELECTED PRECLINICAL AND CLINICAL CONDITIONS, COEXISTENCE OF CELLS IN DIFFERENT ACTIVATION STATES AND UNIQUE OR MIXED PHENOTYPES HAVE BEEN OBSERVED, A REFLECTION OF DYNAMIC CHANGES AND COMPLEX TISSUE-DERIVED SIGNALS. THE IDENTIFICATION OF MECHANISMS AND MOLECULES ASSOCIATED WITH MACROPHAGE PLASTICITY AND POLARIZED ACTIVATION PROVIDES A BASIS FOR MACROPHAGE-CENTERED DIAGNOSTIC AND THERAPEUTIC STRATEGIES. 2012 19 2641 37 EPIGENOMIC AND TRANSCRIPTOMIC ANALYSES REVEAL DIFFERENCES BETWEEN LOW-GRADE INFLAMMATION AND SEVERE EXHAUSTION IN LPS-CHALLENGED MURINE MONOCYTES. EMERGING STUDIES SUGGEST THAT MONOCYTES CAN BE TRAINED BY BACTERIAL ENDOTOXIN TO ADOPT DISTINCT MEMORY STATES RANGING FROM LOW-GRADE INFLAMMATION TO IMMUNE EXHAUSTION. WHILE LOW-GRADE INFLAMMATION MAY CONTRIBUTE TO THE PATHOGENESIS OF CHRONIC DISEASES, EXHAUSTED MONOCYTES WITH PATHOGENIC AND IMMUNE-SUPPRESSIVE CHARACTERISTICS MAY UNDERLIE THE PATHOGENESIS OF POLYMICROBIAL SEPSIS INCLUDING COVID-19. HOWEVER, DETAILED PROCESSES BY WHICH THE DYNAMIC ADAPTION OF MONOCYTES OCCUR REMAIN POORLY UNDERSTOOD. HERE WE EXPOSED MURINE BONE-MARROW DERIVED MONOCYTES TO CHRONIC LIPOPOLYSACCHARIDE (LPS) STIMULATION AT LOW-DOSE OR HIGH-DOSE, AS WELL AS A PBS CONTROL. THE CELLS WERE PROFILED FOR GENOME-WIDE H3K27AC MODIFICATION AND GENE EXPRESSION. THE GENE EXPRESSION OF TRAM-DEFICIENT AND IRAK-M-DEFICIENT MONOCYTES WITH LPS EXPOSURE WAS ALSO ANALYZED. WE DISCOVER THAT LOW-GRADE INFLAMMATION PREFERENTIALLY UTILIZES THE TRAM-DEPENDENT PATHWAY OF TLR4 SIGNALING, AND INDUCES THE EXPRESSION OF INTERFERON RESPONSE GENES. IN CONTRAST, HIGH DOSE LPS UNIQUELY UPREGULATES EXHAUSTION SIGNATURES WITH METABOLIC AND PROLIFERATIVE PATHWAYS. THE EXTENSIVE DIFFERENCES IN THE EPIGENOMIC LANDSCAPE BETWEEN LOW-DOSE AND HIGH-DOSE CONDITIONS SUGGEST THE IMPORTANCE OF EPIGENETIC REGULATIONS IN DRIVING DIFFERENTIAL RESPONSES. OUR DATA PROVIDE POTENTIAL TARGETS FOR FUTURE MECHANISTIC OR THERAPEUTIC STUDIES. 2022 20 5394 37 REDUCED DNA METHYLATION OF SPHINGOSINE-1 PHOSPHATE RECEPTOR 5 IN ALVEOLAR MACROPHAGES IN COPD: A POTENTIAL LINK TO FAILED EFFEROCYTOSIS. BACKGROUND AND OBJECTIVE: WE PREVIOUSLY SHOWED THAT ALVEOLAR MACROPHAGES FROM COPD PATIENTS ARE DEFECTIVE IN THEIR ABILITY TO PHAGOCYTOSE APOPTOTIC CELLS ('EFFEROCYTOSIS') AND THAT THIS DEFECT IS POTENTIALLY LINKED TO THE SPHINGOSINE-1 PHOSPHATE (S1P) SYSTEM, IN PARTICULAR THE SPHINGOSINE-1 PHOSPHATE RECEPTOR 5 (S1PR5). IN ALVEOLAR MACROPHAGES FROM COPD PATIENTS, S1PR5 MRNA EXPRESSION LEVELS INCREASED AND WERE CORRELATED WITH BOTH LUNG FUNCTION AND EFFEROCYTOSIS. HOWEVER, IT US UNKNOWN WHETHER THESE CHANGES ARE UNDER EPIGENETIC CONTROL VIA DNA METHYLATION OR WHETHER DNA METHYLATION DIRECTLY MODULATES MACROPHAGE FUNCTION. METHODS: BISULFITE SEQUENCING WAS USED TO ASSESS DNA METHYLATION LEVELS AT CPG ISLANDS ASSOCIATED WITH GENES ENCODING SELECTED S1P SYSTEM COMPONENTS, INCLUDING SPHINGOSINE KINASE 1 (SPHK1), S1PR1 AND S1PR5, IN ALVEOLAR MACROPHAGES FROM 20 COPD PATIENTS, 7 HEALTHY SMOKERS AND 10 HEALTHY NON/EX-SMOKERS) BY METHYL QUANTITATIVE REAL-TIME PCR (METHYL QPCR). THE EFFECT OF THE DNA METHYLTRANSFERASE INHIBITOR, 5-AZACYTIDINE ON THE EFFEROCYTOSIS CAPACITY OF THP-1 MACROPHAGES WAS ASSESSED USING FLOW CYTOMETRY. RESULTS: AMONG THE S1P SYSTEM GENES EXAMINED, S1PR5 WAS THE SINGLE TARGET THAT SHOWED SIGNIFICANT CHANGES IN DNA METHYLATION BETWEEN PATIENT GROUPS. ALVEOLAR MACROPHAGES ISOLATED FROM COPD PATIENTS SHOWED LOWER METHYLATION LEVELS IN THE SAME REGION COMPARED TO MACROPHAGES FROM NON/EX-SMOKERS. IN VITRO STUDIES USING THP-1 MACROPHAGES SHOWED THAT DNA DEMETHYLATION WITH 5-AZACYTIDINE INCREASED THE EFFEROCYTOSIS CAPACITY AND DOSE-DEPENDENTLY RESCUED THE CELLS FROM THE CIGARETTE SMOKE-INDUCED DEFECT IN EFFEROCYTOSIS. CONCLUSION: MACROPHAGE FUNCTION CAN BE MODULATED EPIGENETICALLY. REDUCED METHYLATION MAY UNDERLIE THE INCREASED EXPRESSION OF THE S1PR5 GENE IN ALVEOLAR MACROPHAGES AND ASSOCIATED DEFECTIVE EFFEROCYTOSIS IN COPD. 2017