1 3184 125 HARNESSING METABOLISM OF HEPATIC MACROPHAGES TO AID LIVER REGENERATION. LIVER REGENERATION IS A DYNAMIC AND REGULATED PROCESS THAT INVOLVES INFLAMMATION, GRANULATION, AND TISSUE REMODELING. HEPATIC MACROPHAGES, ABUNDANTLY DISTRIBUTED IN THE LIVER, ARE ESSENTIAL COMPONENTS THAT ACTIVELY PARTICIPATE IN EACH STEP TO ORCHESTRATE LIVER REGENERATION. IN THE HOMEOSTATIC LIVER, RESIDENT MACROPHAGES (KUPFFER CELLS) ACQUIRE A TOLEROGENIC PHENOTYPE AND CONTRIBUTE TO IMMUNOLOGICAL TOLERANCE. FOLLOWING TOXICITY-INDUCED DAMAGE OR PHYSICAL RESECTION, KUPFFER CELLS AS WELL AS MONOCYTE-DERIVED MACROPHAGES CAN BE ACTIVATED AND PROMOTE AN INFLAMMATORY PROCESS THAT SUPPORTS THE SURVIVAL AND ACTIVATION OF HEPATIC MYOFIBROBLASTS AND THUS PROMOTES SCAR TISSUE FORMATION. SUBSEQUENTLY, THESE MACROPHAGES, IN TURN, EXHIBIT THE ANTI-INFLAMMATORY EFFECTS CRITICAL TO EXTRACELLULAR MATRIX REMODELING DURING THE RESOLUTION STAGE. HOWEVER, CONTINUOUS DAMAGE-INDUCED CHRONIC INFLAMMATION GENERALLY LEADS TO HEPATIC MACROPHAGE DYSFUNCTION, WHICH EXACERBATES HEPATOCELLULAR INJURY AND TRIGGERS FURTHER LIVER FIBROSIS AND EVEN CIRRHOSIS. EMERGING MACROPHAGE-TARGETING STRATEGIES HAVE SHOWN EFFICACY IN BOTH PRECLINICAL AND CLINICAL STUDIES. INCREASING EVIDENCE INDICATES THAT METABOLIC REWIRING PROVIDES SUBSTRATES FOR EPIGENETIC MODIFICATION, WHICH ENDOWS MONOCYTES/MACROPHAGES WITH PROLONGED "INNATE IMMUNE MEMORY". THEREFORE, IT IS REASONABLE TO CONCEIVE NOVEL THERAPEUTIC STRATEGIES FOR METABOLICALLY REPROGRAMMING MACROPHAGES AND THUS MEDIATE A HOMEOSTATIC OR REPARATIVE PROCESS FOR HEPATIC INFLAMMATION MANAGEMENT AND LIVER REGENERATION. 2023 2 1300 33 DEDIFFERENTIATION AND IN VIVO REPROGRAMMING OF COMMITTED CELLS IN WOUND REPAIR (REVIEW). ACCUMULATING EVIDENCE HAS SHOWN THAT CELL DEDIFFERENTIATION OR REPROGRAMMING IS A PIVOTAL PROCEDURE FOR ANIMALS TO DEAL WITH INJURY AND PROMOTE ENDOGENOUS TISSUE REPAIR. TISSUE DAMAGE IS A CRITICAL FACTOR THAT TRIGGERS CELL DEDIFFERENTIATION OR REPROGRAMMING IN VIVO. BY CONTRAST, MICROENVIRONMENTAL CHANGES, INCLUDING THE LOSS OF STEM CELLS, HYPOXIA, CELL SENESCENCE, INFLAMMATION AND IMMUNITY, CAUSED BY TISSUE DAMAGE CAN RETURN CELLS TO AN UNSTABLE STATE. IF THE WOUND PERSISTS IN THE LONG?TERM DUE TO CHRONIC DAMAGE, THEN DEDIFFERENTIATION OR REPROGRAMMING OF THE SURROUNDING CELLS MAY LEAD TO CARCINOGENESIS. IN RECENT YEARS, EXTENSIVE RESEARCH HAS BEEN PERFORMED INVESTIGATING CELL DEDIFFERENTIATION OR REPROGRAMMING IN VIVO, WHICH CAN HAVE SIGNIFICANT IMPLICATIONS FOR WOUND REPAIR, TREATMENT AND PREVENTION OF CANCER IN THE FUTURE. THE CURRENT REVIEW SUMMARIZES THE MOLECULAR EVENTS THAT ARE KNOWN TO DRIVE CELL DEDIFFERENTIATION DIRECTLY FOLLOWING TISSUE INJURY AND THE EFFECTS OF EPIGENETIC MODIFICATION ON DEDIFFERENTIATION OR REPROGRAMMING IN VIVO. IN ADDITION, THE PRESENT REVIEW EXPLORES THE INTRACELLULAR MECHANISM OF ENDOGENOUS TISSUE REPAIR AND ITS RELATIONSHIP WITH CANCER, WHICH IS ESSENTIAL FOR BALANCING THE RISK BETWEEN TISSUE REPAIR AND MALIGNANT TRANSFORMATION AFTER INJURY. 2022 3 4386 26 MITOCHONDRIAL STRESS INDUCED BY CONTINUOUS STIMULATION UNDER HYPOXIA RAPIDLY DRIVES T CELL EXHAUSTION. CANCER AND CHRONIC INFECTIONS INDUCE T CELL EXHAUSTION, A HYPOFUNCTIONAL FATE CARRYING DISTINCT EPIGENETIC, TRANSCRIPTOMIC AND METABOLIC CHARACTERISTICS. HOWEVER, DRIVERS OF EXHAUSTION REMAIN POORLY UNDERSTOOD. AS INTRATUMORAL EXHAUSTED T CELLS EXPERIENCE SEVERE HYPOXIA, WE HYPOTHESIZED THAT METABOLIC STRESS ALTERS THEIR RESPONSES TO OTHER SIGNALS, SPECIFICALLY, PERSISTENT ANTIGENIC STIMULATION. IN VITRO, ALTHOUGH CD8(+) T CELLS EXPERIENCING CONTINUOUS STIMULATION OR HYPOXIA ALONE DIFFERENTIATED INTO FUNCTIONAL EFFECTORS, THE COMBINATION RAPIDLY DROVE T CELL DYSFUNCTION CONSISTENT WITH EXHAUSTION. CONTINUOUS STIMULATION PROMOTED BLIMP-1-MEDIATED REPRESSION OF PGC-1ALPHA-DEPENDENT MITOCHONDRIAL REPROGRAMMING, RENDERING CELLS POORLY RESPONSIVE TO HYPOXIA. LOSS OF MITOCHONDRIAL FUNCTION GENERATED INTOLERABLE LEVELS OF REACTIVE OXYGEN SPECIES (ROS), SUFFICIENT TO PROMOTE EXHAUSTED-LIKE STATES, IN PART THROUGH PHOSPHATASE INHIBITION AND THE CONSEQUENT ACTIVITY OF NUCLEAR FACTOR OF ACTIVATED T CELLS. REDUCING T CELL-INTRINSIC ROS AND LOWERING TUMOR HYPOXIA LIMITED T CELL EXHAUSTION, SYNERGIZING WITH IMMUNOTHERAPY. THUS, IMMUNOLOGIC AND METABOLIC SIGNALING ARE INTRINSICALLY LINKED: THROUGH MITIGATION OF METABOLIC STRESS, T CELL DIFFERENTIATION CAN BE ALTERED TO PROMOTE MORE FUNCTIONAL CELLULAR FATES. 2021 4 5631 33 SENESCENCE-INFLAMMATORY REGULATION OF REPARATIVE CELLULAR REPROGRAMMING IN AGING AND CANCER. THE INABILITY OF ADULT TISSUES TO TRANSITORILY GENERATE CELLS WITH FUNCTIONAL STEM CELL-LIKE PROPERTIES IS A MAJOR OBSTACLE TO TISSUE SELF-REPAIR. NUCLEAR REPROGRAMMING-LIKE PHENOMENA THAT INDUCE A TRANSIENT ACQUISITION OF EPIGENETIC PLASTICITY AND PHENOTYPE MALLEABILITY MAY CONSTITUTE A REPARATIVE ROUTE THROUGH WHICH HUMAN TISSUES RESPOND TO INJURY, STRESS, AND DISEASE. HOWEVER, TISSUE REJUVENATION SHOULD INVOLVE NOT ONLY THE TRANSIENT EPIGENETIC REPROGRAMMING OF DIFFERENTIATED CELLS, BUT ALSO THE COMMITTED RE-ACQUISITION OF THE ORIGINAL OR ALTERNATIVE COMMITTED CELL FATE. CHRONIC OR UNRESTRAINED EPIGENETIC PLASTICITY WOULD DRIVE AGING PHENOTYPES BY IMPAIRING THE REPAIR OR THE REPLACEMENT OF DAMAGED CELLS; SUCH UNCONTROLLED PHENOMENA OF IN VIVO REPROGRAMMING MIGHT ALSO GENERATE CANCER-LIKE CELLULAR STATES. WE HEREIN PROPOSE THAT THE ABILITY OF SENESCENCE-ASSOCIATED INFLAMMATORY SIGNALING TO REGULATE IN VIVO REPROGRAMMING CYCLES OF TISSUE REPAIR OUTLINES A THRESHOLD MODEL OF AGING AND CANCER. THE DEGREE OF SENESCENCE/INFLAMMATION-ASSOCIATED DEVIATION FROM THE HOMEOSTATIC STATE MAY DELINEATE A TYPE OF THRESHOLDING ALGORITHM DISTINGUISHING BENEFICIAL FROM DELETERIOUS EFFECTS OF IN VIVO REPROGRAMMING. FIRST, TRANSIENT ACTIVATION OF NF-KAPPAB-RELATED INNATE IMMUNITY AND SENESCENCE-ASSOCIATED INFLAMMATORY COMPONENTS (E.G., IL-6) MIGHT FACILITATE REPARATIVE CELLULAR REPROGRAMMING IN RESPONSE TO ACUTE INFLAMMATORY EVENTS. SECOND, PARA-INFLAMMATION SWITCHES MIGHT PROMOTE LONG-LASTING BUT REVERSIBLE REFRACTORINESS TO REPARATIVE CELLULAR REPROGRAMMING. THIRD, CHRONIC SENESCENCE-ASSOCIATED INFLAMMATORY SIGNALING MIGHT LOCK CELLS IN HIGHLY PLASTIC EPIGENETIC STATES DISABLED FOR REPARATIVE DIFFERENTIATION. THE CONSIDERATION OF A CELLULAR REPROGRAMMING-CENTERED VIEW OF EPIGENETIC PLASTICITY AS A FUNDAMENTAL ELEMENT OF A TISSUE'S CAPACITY TO UNDERGO SUCCESSFUL REPAIR, AGING DEGENERATION OR MALIGNANT TRANSFORMATION SHOULD PROVIDE CHALLENGING STOCHASTIC INSIGHTS INTO THE CURRENT DETERMINISTIC GENETIC PARADIGM FOR MOST CHRONIC DISEASES, THEREBY INCREASING THE SPECTRUM OF THERAPEUTIC APPROACHES FOR PHYSIOLOGICAL AGING AND CANCER. 2017 5 2344 27 EPIGENETIC REGULATION OF MACROPHAGES: FROM HOMEOSTASIS MAINTENANCE TO HOST DEFENSE. MACROPHAGES ARE CRUCIAL MEMBERS OF THE INNATE IMMUNE RESPONSE AND IMPORTANT REGULATORS. THE DIFFERENTIATION AND ACTIVATION OF MACROPHAGES REQUIRE THE TIMELY REGULATION OF GENE EXPRESSION, WHICH DEPENDS ON THE INTERACTION OF A VARIETY OF FACTORS, INCLUDING TRANSCRIPTION FACTORS AND EPIGENETIC MODIFICATIONS. EPIGENETIC CHANGES ALSO GIVE MACROPHAGES THE ABILITY TO SWITCH RAPIDLY BETWEEN CELLULAR PROGRAMS, INDICATING THE ABILITY OF EPIGENETIC MECHANISMS TO AFFECT PHENOTYPE PLASTICITY. IN THIS REVIEW, WE FOCUS ON KEY EPIGENETIC EVENTS ASSOCIATED WITH MACROPHAGE FATE, HIGHLIGHTING EVENTS RELATED TO THE MAINTENANCE OF TISSUE HOMEOSTASIS, RESPONSES TO DIFFERENT STIMULI AND THE FORMATION OF INNATE IMMUNE MEMORY. FURTHER UNDERSTANDING OF THE EPIGENETIC REGULATION OF MACROPHAGES WILL BE HELPFUL FOR MAINTAINING TISSUE INTEGRITY, PREVENTING CHRONIC INFLAMMATORY DISEASES AND DEVELOPING THERAPIES TO ENHANCE HOST DEFENSE. 2020 6 6365 29 THE ROLE OF METABOLIC DYSFUNCTION IN T-CELL EXHAUSTION DURING CHRONIC VIRAL INFECTION. T CELLS ARE IMPORTANT COMPONENTS OF ADAPTIVE IMMUNITY THAT PROTECT THE HOST AGAINST INVADING PATHOGENS DURING INFECTION. UPON RECOGNIZING THE ACTIVATION SIGNALS, NAIVE AND/OR MEMORY T CELLS WILL INITIATE CLONAL EXPANSION, TRIGGER DIFFERENTIATION INTO EFFECTOR POPULATIONS AND TRAFFIC TO THE INFLAMED SITES TO ELIMINATE PATHOGENS. HOWEVER, IN CHRONIC VIRAL INFECTIONS, SUCH AS THOSE CAUSED BY HUMAN IMMUNODEFICIENCY VIRUS (HIV), HEPATITIS B AND C (HBV AND HCV), T CELLS EXHIBIT IMPAIRED FUNCTION AND BECOME DIFFICULT TO CLEAR PATHOGENS IN A STATE KNOWN AS T-CELL EXHAUSTION. THE ACTIVATION AND FUNCTION PERSISTENCE OF T CELLS DEMAND FOR DYNAMIC CHANGES IN CELLULAR METABOLISM TO MEET THEIR BIOENERGETIC AND BIOSYNTHETIC DEMANDS, ESPECIALLY THE AUGMENTATION OF AEROBIC GLYCOLYSIS, WHICH NOT ONLY PROVIDE EFFICIENT ENERGY GENERATION, BUT ALSO FUEL MULTIPLE BIOCHEMICAL INTERMEDIATES THAT ARE ESSENTIAL FOR NUCLEOTIDE, AMINO ACID, FATTY ACID SYNTHESIS AND MITOCHONDRIA FUNCTION. CHANGES IN CELLULAR METABOLISM ALSO AFFECT THE FUNCTION OF EFFECTORS T CELLS THROUGH MODIFYING EPIGENETIC SIGNATURES. IT IS WIDELY ACCEPTED THAT THE DYSFUNCTION OF T CELL METABOLISM CONTRIBUTES GREATLY TO T-CELL EXHAUSTION. HERE, WE REVIEWED RECENT FINDINGS ON T CELLS METABOLISM UNDER CHRONIC VIRAL INFECTION, SEEKING TO REVEAL THE ROLE OF METABOLIC DYSFUNCTION PLAYED IN T-CELL EXHAUSTION. 2022 7 3688 33 INFLAMMATION: GEARING THE JOURNEY TO CANCER. CHRONIC INFLAMMATION PLAYS A MULTIFACETED ROLE IN CARCINOGENESIS. MOUNTING EVIDENCE FROM PRECLINICAL AND CLINICAL STUDIES SUGGESTS THAT PERSISTENT INFLAMMATION FUNCTIONS AS A DRIVING FORCE IN THE JOURNEY TO CANCER. THE POSSIBLE MECHANISMS BY WHICH INFLAMMATION CAN CONTRIBUTE TO CARCINOGENESIS INCLUDE INDUCTION OF GENOMIC INSTABILITY, ALTERATIONS IN EPIGENETIC EVENTS AND SUBSEQUENT INAPPROPRIATE GENE EXPRESSION, ENHANCED PROLIFERATION OF INITIATED CELLS, RESISTANCE TO APOPTOSIS, AGGRESSIVE TUMOR NEOVASCULARIZATION, INVASION THROUGH TUMOR-ASSOCIATED BASEMENT MEMBRANE AND METASTASIS, ETC. INFLAMMATION-INDUCED REACTIVE OXYGEN AND NITROGEN SPECIES CAUSE DAMAGE TO IMPORTANT CELLULAR COMPONENTS (E.G., DNA, PROTEINS AND LIPIDS), WHICH CAN DIRECTLY OR INDIRECTLY CONTRIBUTE TO MALIGNANT CELL TRANSFORMATION. OVEREXPRESSION, ELEVATED SECRETION, OR ABNORMAL ACTIVATION OF PROINFLAMMATORY MEDIATORS, SUCH AS CYTOKINES, CHEMOKINES, CYCLOOXYGENASE-2, PROSTAGLANDINS, INDUCIBLE NITRIC OXIDE SYNTHASE, AND NITRIC OXIDE, AND A DISTINCT NETWORK OF INTRACELLULAR SIGNALING MOLECULES INCLUDING UPSTREAM KINASES AND TRANSCRIPTION FACTORS FACILITATE TUMOR PROMOTION AND PROGRESSION. WHILE INFLAMMATION PROMOTES DEVELOPMENT OF CANCER, COMPONENTS OF THE TUMOR MICROENVIRONMENT, SUCH AS TUMOR CELLS, STROMAL CELLS IN SURROUNDING TISSUE AND INFILTRATED INFLAMMATORY/IMMUNE CELLS GENERATE AN INTRATUMORAL INFLAMMATORY STATE BY ABERRANT EXPRESSION OR ACTIVATION OF SOME PROINFLAMMATORY MOLECULES. MANY OF PROINFLAMMATORY MEDIATORS, ESPECIALLY CYTOKINES, CHEMOKINES AND PROSTAGLANDINS, TURN ON THE ANGIOGENIC SWITCHES MAINLY CONTROLLED BY VASCULAR ENDOTHELIAL GROWTH FACTOR, THEREBY INDUCING INFLAMMATORY ANGIOGENESIS AND TUMOR CELL-STROMA COMMUNICATION. THIS WILL END UP WITH TUMOR ANGIOGENESIS, METASTASIS AND INVASION. MOREOVER, CELLULAR MICRORNAS ARE EMERGING AS A POTENTIAL LINK BETWEEN INFLAMMATION AND CANCER. THE PRESENT ARTICLE HIGHLIGHTS THE ROLE OF VARIOUS PROINFLAMMATORY MEDIATORS IN CARCINOGENESIS AND THEIR PROMISE AS POTENTIAL TARGETS FOR CHEMOPREVENTION OF INFLAMMATION-ASSOCIATED CARCINOGENESIS. 2008 8 2342 29 EPIGENETIC REGULATION OF MACROPHAGE POLARIZATION AND FUNCTION. MACROPHAGE POLARIZATION REFERS TO DEVELOPMENT OF A SPECIFIC PHENOTYPE IMPORTANT FOR TISSUE HOMEOSTASIS OR HOST DEFENSE IN RESPONSE TO ENVIRONMENTAL CUES. ENVIRONMENTAL FACTORS THAT INDUCE MACROPHAGE POLARIZATION INCLUDE CYTOKINES AND MICROBIAL FACTORS PRODUCED BY PATHOGENS OR COMMENSAL MICROBIOTA. SIGNALING PATHWAYS UTILIZED BY THESE POLARIZING FACTORS HAVE BEEN WELL CHARACTERIZED, BUT IT IS LESS CLEAR HOW SIGNALS ARE CONVERTED INTO COMPLEX AND SUSTAINED PATTERNS OF GENE EXPRESSION, AND HOW MACROPHAGES ARE REPROGRAMMED DURING POLARIZATION TO ALTER THEIR RESPONSES TO SUBSEQUENT ENVIRONMENTAL CHALLENGES. EMERGING EVIDENCE, REVIEWED HERE, SUGGESTS AN IMPORTANT ROLE FOR EPIGENETIC MECHANISMS IN MODULATING AND TRANSMITTING SIGNALS DURING MACROPHAGE POLARIZATION AND REPROGRAMMING. DEEPER UNDERSTANDING OF EPIGENETIC REGULATION OF MACROPHAGE PHENOTYPE WILL ENABLE DEVELOPMENT OF GENE-SPECIFIC THERAPEUTIC APPROACHES TO ENHANCE HOST DEFENSE WHILE PRESERVING TISSUE INTEGRITY AND PREVENTING CHRONIC INFLAMMATORY DISEASES. 2013 9 6452 32 THERAPIES TARGETING TRAINED IMMUNE CELLS IN INFLAMMATORY AND AUTOIMMUNE DISEASES. THE CONCEPT OF TRAINED IMMUNITY HAS RECENTLY EMERGED AS A MECHANISM CONTRIBUTING TO SEVERAL IMMUNE MEDIATED INFLAMMATORY CONDITIONS. TRAINED IMMUNITY IS DEFINED BY THE IMMUNOLOGICAL MEMORY DEVELOPED IN INNATE IMMUNE CELLS AFTER A PRIMARY NON-SPECIFIC STIMULUS THAT, IN TURN, PROMOTES A HEIGHTENED INFLAMMATORY RESPONSE UPON A SECONDARY CHALLENGE. THE MOST CHARACTERISTIC CHANGES ASSOCIATED TO THIS PROCESS INVOLVE THE REWIRING OF CELL METABOLISM AND EPIGENETIC REPROGRAMMING. UNDER PHYSIOLOGICAL CONDITIONS, THE ROLE OF TRAINED IMMUNE CELLS ENSURES A PROMPT RESPONSE. THIS ACTION IS LIMITED BY EFFECTIVE RESOLUTION OF INFLAMMATION AND TISSUE REPAIR IN ORDER TO RESTORE HOMEOSTASIS. HOWEVER, UNRESTRAINED ACTIVATION OF INNATE IMMUNE CELLS CONTRIBUTES TO THE DEVELOPMENT OF CHRONIC INFLAMMATION AND TISSUE DESTRUCTION THROUGH THE SECRETION OF INFLAMMATORY CYTOKINES, PROTEASES AND GROWTH FACTORS. THEREFORE, INTERVENTIONS AIMED AT REVERSING THE CHANGES INDUCED BY TRAINED IMMUNITY PROVIDE POTENTIAL THERAPEUTIC APPROACHES TO TREAT INFLAMMATORY AND AUTOIMMUNE DISEASES LIKE RHEUMATOID ARTHRITIS (RA). WE REVIEW CELLULAR APPROACHES THAT TARGET METABOLISM AND THE EPIGENETIC REPROGRAMMING OF DENDRITIC CELLS, MACROPHAGES, NATURAL KILLER CELLS, AND OTHER TRAINED CELLS IN THE CONTEXT OF AUTOIMMUNE INFLAMMATORY DISEASES. 2020 10 3732 27 INNATE IMMUNE MEMORY AND THE HOST RESPONSE TO INFECTION. UNLIKE THE ADAPTIVE IMMUNE SYSTEM, THE INNATE IMMUNE SYSTEM HAS CLASSICALLY BEEN CHARACTERIZED AS BEING DEVOID OF MEMORY FUNCTIONS. HOWEVER, RECENT RESEARCH SHOWS THAT INNATE MYELOID AND LYMPHOID CELLS HAVE THE ABILITY TO RETAIN MEMORY OF PRIOR PATHOGEN EXPOSURE AND BECOME PRIMED TO ELICIT A ROBUST, BROAD-SPECTRUM RESPONSE TO SUBSEQUENT INFECTION. THIS PHENOMENON HAS BEEN TERMED INNATE IMMUNE MEMORY OR TRAINED IMMUNITY. INNATE IMMUNE MEMORY IS INDUCED VIA ACTIVATION OF PATTERN RECOGNITION RECEPTORS AND THE ACTIONS OF CYTOKINES ON HEMATOPOIETIC PROGENITORS AND STEM CELLS IN BONE MARROW AND INNATE LEUKOCYTES IN THE PERIPHERY. THE TRAINED PHENOTYPE IS INDUCED AND SUSTAINED VIA EPIGENETIC MODIFICATIONS THAT REPROGRAM TRANSCRIPTIONAL PATTERNS AND METABOLISM. THESE MODIFICATIONS AUGMENT ANTIMICROBIAL FUNCTIONS, SUCH AS LEUKOCYTE EXPANSION, CHEMOTAXIS, PHAGOCYTOSIS, AND MICROBIAL KILLING, TO FACILITATE AN AUGMENTED HOST RESPONSE TO INFECTION. ALTERNATIVELY, INNATE IMMUNE MEMORY MAY CONTRIBUTE TO THE PATHOGENESIS OF CHRONIC DISEASES, SUCH AS ATHEROSCLEROSIS AND ALZHEIMER'S DISEASE. 2022 11 3734 45 INNATE IMMUNE MEMORY IN MONOCYTES AND MACROPHAGES: THE POTENTIAL THERAPEUTIC STRATEGIES FOR ATHEROSCLEROSIS. ATHEROSCLEROSIS IS A COMPLEX METABOLIC DISEASE CHARACTERIZED BY THE DYSFUNCTION OF LIPID METABOLISM AND CHRONIC INFLAMMATION IN THE INTIMAL SPACE OF THE VESSEL. AS THE MOST ABUNDANT INNATE IMMUNE CELLS, MONOCYTE-DERIVED MACROPHAGES PLAY A PIVOTAL ROLE IN THE INFLAMMATORY RESPONSE, CHOLESTEROL METABOLISM, AND FOAM CELL FORMATION. IN RECENT DECADES, IT HAS BEEN DEMONSTRATED THAT MONOCYTES AND MACROPHAGES CAN ESTABLISH INNATE IMMUNE MEMORY (ALSO TERMED TRAINED IMMUNITY) VIA ENDOGENOUS AND EXOGENOUS ATHEROGENIC STIMULI AND EXHIBIT A LONG-LASTING PROINFLAMMATORY PHENOTYPE. THE IMPORTANT CELLULAR METABOLISM PROCESSES, INCLUDING GLYCOLYSIS, OXIDATIVE PHOSPHORYLATION (OXPHOS), THE TRICARBOXYLIC ACID (TCA) CYCLE, FATTY ACID SYNTHESIS, AND CHOLESTEROL SYNTHESIS, ARE REPROGRAMMED. TRAINED MONOCYTES/MACROPHAGES WITH INNATE IMMUNE MEMORY CAN BE PERSISTENTLY HYPERACTIVATED AND CAN UNDERGO EXTENSIVE EPIGENETIC REWIRING, WHICH CONTRIBUTES TO THE PATHOPHYSIOLOGICAL DEVELOPMENT OF ATHEROSCLEROSIS VIA INCREASED PROINFLAMMATORY CYTOKINE PRODUCTION AND LIPID ACCUMULATION. HERE, WE PROVIDE AN OVERVIEW OF THE REGULATION OF CELLULAR METABOLIC PROCESSES AND EPIGENETIC MODIFICATIONS OF INNATE IMMUNE MEMORY IN MONOCYTES/MACROPHAGES AS WELL AS THE POTENTIAL ENDOGENOUS AND EXOGENOUS STIMULATIONS INVOLVED IN THE PROGRESSION OF ATHEROSCLEROSIS THAT HAVE BEEN REPORTED RECENTLY. THESE ELUCIDATIONS MIGHT BE BENEFICIAL FOR FURTHER UNDERSTANDING INNATE IMMUNE MEMORY AND THE DEVELOPMENT OF THERAPEUTIC STRATEGIES FOR INFLAMMATORY DISEASES AND ATHEROSCLEROSIS. 2022 12 6151 27 THE FIRE WITHIN: CELL-AUTONOMOUS MECHANISMS IN INFLAMMATION-DRIVEN CANCER. INFLAMMATORY CELLS ARE IMPORTANT FOR TUMOR INITIATION AND PROMOTION, PROVIDING CANCER CELLS WITH CYTOKINES THAT ENHANCE CELL PROLIFERATION AND SURVIVAL. ALTHOUGH MALIGNANT EPITHELIAL CELLS WERE TRADITIONALLY CONSIDERED TO BE ON THE RECEIVING END OF THESE MICROENVIRONMENTAL INTERACTIONS, RECENT STUDIES SHOW THAT EPITHELIAL CELLS CAN UNDERGO INFLAMMATORY REPROGRAMMING ON THEIR OWN. SUCH EPIGENETIC SWITCHES ARE OFTEN TRIGGERED BY CHRONIC TISSUE INJURY AND PLAY IMPORTANT ROLES IN TISSUE REPAIR. BY CONVERTING TERMINALLY DIFFERENTIATED CELLS THAT HARBOR EVEN A SINGLE ONCOGENIC MUTATION TO A LESS DIFFERENTIATED STATE WITH A HIGHER PROLIFERATIVE POTENTIAL, CELL-AUTONOMOUS INFLAMMATION IS AN IMPORTANT CONTRIBUTOR TO TUMOR INITIATION. 2019 13 5726 18 SKIN WELL-BEING IN DIABETES: ROLE OF MACROPHAGES. MACROPHAGES ARE KEY PLAYERS IN WOUND HEALING- ALONG WITH MEDIATING THE ACUTE INFLAMMATORY RESPONSE, MACROPHAGES ACTIVATE CUTANEOUS EPITHELIAL CELLS AND PROMOTE TISSUE REPAIR. DIABETES COMPLICATIONS, INCLUDING DIABETIC CHRONIC WOUNDS, ARE ACCOMPANIED BY PERSISTENT INFLAMMATION AND MACROPHAGE MALFUNCTION. SEVERAL STUDIES INDICATE THAT HYPERGLYCEMIA INDUCES VARIOUS ALTERATIONS THAT AFFECT MACROPHAGE FUNCTION IN WOUND HEALING INCLUDING EPIGENETIC CHANGES, IMBALANCE BETWEEN PRO- AND ANTI-INFLAMMATORY MODULATORS, AND INSENSITIVITY TO PROLIFERATIVE STIMULI. IN THIS REVIEW, WE BRIEFLY SUMMARIZE RECENT STUDIES REGARDING THOSE ALTERATIONS AND THEIR IMPLICATIONS ON SKIN WELL-BEING IN DIABETES. 2020 14 5816 23 STRESS AND STEM CELLS. THE UNIQUE PROPERTIES AND FUNCTIONS OF STEM CELLS MAKE THEM PARTICULARLY SUSCEPTIBLE TO STRESSES AND ALSO LEAD TO THEIR REGULATION BY STRESS. STEM CELL DIVISION MUST RESPOND TO THE DEMAND TO REPLENISH CELLS DURING NORMAL TISSUE TURNOVER AS WELL AS IN RESPONSE TO DAMAGE. OXIDATIVE STRESS, MECHANICAL STRESS, GROWTH FACTORS, AND CYTOKINES SIGNAL STEM CELL DIVISION AND DIFFERENTIATION. MANY OF THE CONSERVED PATHWAYS REGULATING STEM CELL SELF-RENEWAL AND DIFFERENTIATION ARE ALSO STRESS-RESPONSE PATHWAYS. THE LONG LIFE SPAN AND DIVISION POTENTIAL OF STEM CELLS CREATE A PROPENSITY FOR TRANSFORMATION (CANCER) AND SPECIFIC STRESS RESPONSES SUCH AS APOPTOSIS AND SENESCENCE ACT AS ANTITUMOR MECHANISMS. QUIESCENCE REGULATED BY CDK INHIBITORS AND A HYPOXIC NICHE REGULATED BY FOXO TRANSCRIPTION FACTOR FUNCTION TO REDUCE STRESS FOR SEVERAL TYPES OF STEM CELLS TO FACILITATE LONG-TERM MAINTENANCE. AGING IS A PARTICULARLY RELEVANT STRESS FOR STEM CELLS, BECAUSE REPEATED DEMANDS ON STEM CELL FUNCTION OVER THE LIFE SPAN CAN HAVE CUMULATIVE CELL-AUTONOMOUS EFFECTS INCLUDING EPIGENETIC DYSREGULATION, MUTATIONS, AND TELOMERE EROSION. IN ADDITION, AGING OF THE ORGANISM IMPAIRS FUNCTION OF THE STEM CELL NICHE AND SYSTEMIC SIGNALS, INCLUDING CHRONIC INFLAMMATION AND OXIDATIVE STRESS. 2012 15 5412 31 REGULATION OF ANTITUMOR IMMUNITY BY INFLAMMATION-INDUCED EPIGENETIC ALTERATIONS. CHRONIC INFLAMMATION PROMOTES TUMOR DEVELOPMENT, PROGRESSION, AND METASTATIC DISSEMINATION AND CAUSES TREATMENT RESISTANCE. THE ACCUMULATION OF GENETIC ALTERATIONS AND LOSS OF NORMAL CELLULAR REGULATORY PROCESSES ARE NOT ONLY ASSOCIATED WITH CANCER GROWTH AND PROGRESSION BUT ALSO RESULT IN THE EXPRESSION OF TUMOR-SPECIFIC AND TUMOR-ASSOCIATED ANTIGENS THAT MAY ACTIVATE ANTITUMOR IMMUNITY. THIS ANTAGONISM BETWEEN INFLAMMATION AND IMMUNITY AND THE ABILITY OF CANCER CELLS TO AVOID IMMUNE DETECTION AFFECT THE COURSE OF CANCER DEVELOPMENT AND TREATMENT OUTCOMES. WHILE INFLAMMATION, PARTICULARLY ACUTE INFLAMMATION, SUPPORTS T-CELL PRIMING, ACTIVATION, AND INFILTRATION INTO INFECTED TISSUES, CHRONIC INFLAMMATION IS MOSTLY IMMUNOSUPPRESSIVE. HOWEVER, THE MAIN MECHANISMS THAT DICTATE THE OUTCOME OF THE INFLAMMATION-IMMUNITY INTERPLAY ARE NOT WELL UNDERSTOOD. RECENT DATA SUGGEST THAT INFLAMMATION TRIGGERS EPIGENETIC ALTERATIONS IN CANCER CELLS AND COMPONENTS OF THE TUMOR MICROENVIRONMENT. THESE ALTERATIONS CAN AFFECT AND MODULATE NUMEROUS ASPECTS OF CANCER DEVELOPMENT, INCLUDING TUMOR GROWTH, THE METABOLIC STATE, METASTATIC SPREAD, IMMUNE ESCAPE, AND IMMUNOSUPPRESSIVE OR IMMUNOSUPPORTIVE LEUKOCYTE GENERATION. IN THIS REVIEW, WE DISCUSS THE ROLE OF INFLAMMATION IN INITIATING EPIGENETIC ALTERATIONS IN IMMUNE CELLS, CANCER-ASSOCIATED FIBROBLASTS, AND CANCER CELLS AND SUGGEST HOW AND WHEN EPIGENETIC INTERVENTIONS CAN BE COMBINED WITH IMMUNOTHERAPIES TO IMPROVE THERAPEUTIC OUTCOMES. 2022 16 2069 34 EPIGENETIC CONTROL OF SKELETAL MUSCLE REGENERATION: INTEGRATING GENETIC DETERMINANTS AND ENVIRONMENTAL CHANGES. DURING EMBRYONIC DEVELOPMENT, PLURIPOTENT CELLS ARE GENETICALLY COMMITTED TO SPECIFIC LINEAGES BY THE EXPRESSION OF CELL-TYPE-SPECIFIC TRANSCRIPTIONAL ACTIVATORS THAT DIRECT THE FORMATION OF SPECIALIZED TISSUES AND ORGANS IN RESPONSE TO DEVELOPMENTAL CUES. CHROMATIN-MODIFYING PROTEINS ARE EMERGING AS ESSENTIAL COMPONENTS OF THE EPIGENETIC MACHINERY, WHICH ESTABLISHES THE NUCLEAR LANDSCAPE THAT ULTIMATELY DETERMINES THE FINAL IDENTITY AND FUNCTIONAL SPECIALIZATION OF ADULT CELLS. RECENT EVIDENCE HAS REVEALED THAT DISCRETE POPULATIONS OF ADULT CELLS CAN RETAIN THE ABILITY TO ADOPT ALTERNATIVE CELL FATES IN RESPONSE TO ENVIRONMENTAL CUES. THESE CELLS INCLUDE CONVENTIONAL ADULT STEM CELLS AND A STILL POORLY DEFINED COLLECTION OF CELL TYPES ENDOWED WITH FACULTATIVE PHENOTYPE AND FUNCTIONAL PLASTICITY. UNDER PHYSIOLOGICAL CONDITIONS OR ADAPTIVE STATES, THESE CELLS COOPERATE TO SUPPORT TISSUE AND ORGAN HOMEOSTASIS, AND TO PROMOTE GROWTH OR COMPENSATORY REGENERATION. HOWEVER, DURING CHRONIC DISEASES AND AGING THESE CELLS CAN ADOPT A PATHOLOGICAL PHENOTYPE AND MEDIATE MALADAPTIVE RESPONSES, SUCH AS THE FORMATION OF FIBROTIC SCARS AND FAT DEPOSITION THAT PROGRESSIVELY REPLACES STRUCTURAL AND FUNCTIONAL UNITS OF TISSUES AND ORGANS. THE MOLECULAR DETERMINANTS OF THESE PHENOTYPIC TRANSITIONS ARE ONLY EMERGING FROM RECENT STUDIES THAT REVEAL HOW DYNAMIC CHROMATIN STATES CAN GENERATE FLEXIBLE EPIGENETIC LANDSCAPES, WHICH CONFER ON CELLS THE ABILITY TO RETAIN PARTIAL PLURIPOTENCY AND ADAPT TO ENVIRONMENTAL CHANGES. THIS REVIEW SUMMARIZES OUR CURRENT KNOWLEDGE ON THE ROLE OF THE EPIGENETIC MACHINERY AS A 'FILTER' BETWEEN GENETIC COMMITMENT AND ENVIRONMENTAL SIGNALS IN CELL TYPES THAT CAN ALTERNATIVELY PROMOTE SKELETAL MUSCLE REGENERATION OR FIBRO-ADIPOGENIC DEGENERATION. 2013 17 6591 28 TUMOR-ASSOCIATED MACROPHAGES AS A PARADIGM OF MACROPHAGE PLASTICITY, DIVERSITY, AND POLARIZATION: LESSONS AND OPEN QUESTIONS. MACROPHAGES ARE PRESENT IN ALL BODY COMPARTMENTS, INCLUDING CANCEROUS TISSUES, AND THEIR FUNCTIONS ARE PROFOUNDLY AFFECTED BY SIGNALS FROM THE MICROENVIRONMENT UNDER HOMEOSTATIC AND PATHOLOGICAL CONDITIONS. TUMOR-ASSOCIATED MACROPHAGES ARE A MAJOR CELLULAR COMPONENT OF CANCER-RELATED INFLAMMATION AND HAVE SERVED AS A PARADIGM FOR THE PLASTICITY AND FUNCTIONAL POLARIZATION OF MONONUCLEAR PHAGOCYTES. TUMOR-ASSOCIATED MACROPHAGES CAN EXERT DUAL INFLUENCE OF CANCER DEPENDING ON THE ACTIVATION STATE, WITH CLASSICALLY ACTIVATED (M1) AND ALTERNATIVELY ACTIVATED (M2) CELLS GENERALLY EXERTING ANTITUMORAL AND PROTUMORAL FUNCTIONS, RESPECTIVELY. THESE ARE EXTREMES IN A CONTINUUM OF POLARIZATION STATES IN A UNIVERSE OF DIVERSITY. TUMOR-ASSOCIATED MACROPHAGES AFFECT VIRTUALLY ALL ASPECTS OF TUMOR TISSUES, INCLUDING STEM CELLS, METABOLISM, ANGIOGENESIS, INVASION, AND METASTASIS. PROGRESS HAS BEEN MADE IN DEFINING SIGNALING MOLECULES, TRANSCRIPTION FACTORS, EPIGENETIC CHANGES, AND REPERTOIRE OF MICRORNAS UNDERLYING MACROPHAGE POLARIZATION. PRECLINICAL AND EARLY CLINICAL DATA SUGGEST THAT MACROPHAGES MAY SERVE AS TOOLS FOR THE DEVELOPMENT OF INNOVATIVE DIAGNOSTIC AND THERAPEUTIC STRATEGIES IN CANCER AND CHRONIC NONRESOLVING INFLAMMATORY DISEASES. 2013 18 6592 35 TUMOR-ASSOCIATED MACROPHAGES IN HEPATOCELLULAR CARCINOMA PATHOGENESIS, PROGNOSIS AND THERAPY. HEPATOCELLULAR CARCINOMA (HCC) CONSTITUTES A MAJOR HEALTH BURDEN GLOBALLY, AND IT IS CAUSED BY INTRINSIC GENETIC MUTATIONS ACTING IN CONCERT WITH A MULTITUDE OF EPIGENETIC AND EXTRINSIC RISK FACTORS. CANCER INDUCES MYELOPOIESIS IN THE BONE MARROW, AS WELL AS THE MOBILIZATION OF HEMATOPOIETIC STEM AND PROGENITOR CELLS, WHICH RESIDE IN THE SPLEEN. MONOCYTES PRODUCED IN THE BONE MARROW AND THE SPLEEN FURTHER INFILTRATE TUMORS, WHERE THEY DIFFERENTIATE INTO TUMOR-ASSOCIATED MACROPHAGES (TAMS). THE RELATIONSHIP BETWEEN CHRONIC INFLAMMATION AND HEPATOCARCINOGENESIS HAS BEEN THOROUGHLY INVESTIGATED OVER THE PAST DECADE; HOWEVER, SEVERAL ASPECTS OF THE ROLE OF TAMS IN HCC DEVELOPMENT ARE YET TO BE DETERMINED. IN RESPONSE TO CERTAIN STIMULI AND SIGNALING, MONOCYTES DIFFERENTIATE INTO MACROPHAGES WITH ANTITUMOR PROPERTIES, WHICH ARE CLASSIFIED AS M1-LIKE. ON THE OTHER HAND, UNDER DIFFERENT STIMULI AND SIGNALING, THE POLARIZATION OF MACROPHAGES SHIFTS TOWARDS AN M2-LIKE PHENOTYPE WITH A TUMOR PROMOTING CAPACITY. M2-LIKE MACROPHAGES DRIVE TUMOR GROWTH BOTH DIRECTLY AND INDIRECTLY, VIA THE SUPPRESSION OF CYTOTOXIC CELL POPULATIONS, INCLUDING CD8+ T CELLS AND NK CELLS. THE TUMOR MICROENVIRONMENT AFFECTS THE RESPONSE TO IMMUNOTHERAPIES. THEREFORE, AN ENHANCED UNDERSTANDING OF ITS IMMUNOBIOLOGY IS ESSENTIAL FOR THE DEVELOPMENT OF NEXT-GENERATION IMMUNOTHERAPIES. THE UTILIZATION OF VARIOUS MONOCYTE-CENTERED ANTICANCER TREATMENT MODALITIES HAS BEEN UNDER CLINICAL INVESTIGATION, SELECTIVELY TARGETING AND MODULATING THE PROCESSES OF MONOCYTE RECRUITMENT, ACTIVATION AND MIGRATION. THIS REVIEW SUMMARIZES THE CURRENT EVIDENCE ON THE ROLE OF TAMS IN HCC PATHOGENESIS AND PROGRESSION, AS WELL AS IN THEIR POTENTIAL INVOLVEMENT IN TUMOR THERAPY, SHEDDING LIGHT ON EMERGING ANTICANCER TREATMENT METHODS TARGETING MONOCYTES. 2022 19 2800 28 FEEDBACK REGULATORS OF HYPOXIA-INDUCIBLE FACTORS AND THEIR ROLE IN CANCER BIOLOGY. MALIGNANT TUMORS ARE CHARACTERIZED BY REGIONS OF LOW OXYGEN CONCENTRATION (HYPOXIA). THE HYPOXIC TUMOR MICROENVIRONMENT CONTRIBUTES TO TUMOR PROGRESSION BY ACTIVATING A SET OF ADAPTIVE RESPONSES VIA THE KEY TRANSCRIPTIONAL REGULATORS HIF-1ALPHA AND HIF-2ALPHA. THESE FACTORS HAVE BEEN TRADITIONALLY LINKED TO AN AGGRESSIVE TUMOR PHENOTYPE BY PROMOTING PROCESSES ESSENTIAL FOR TUMOR GROWTH, SUCH AS ANGIOGENESIS, GLYCOLYSIS, METASTASIS AND INVASION, AS WELL AS DIFFERENTIATION AND SELF RENEWAL. NOTABLY, THE COMPLEX HIF PATHWAY ALSO INITIATES ANTI-TUMORIGENIC MECHANISMS THAT LEAD TO CELL CYCLE ARREST OR CELL DEATH, INDICATING THE NEED FOR A STRINGENT CONTROL OF THE EXTENT AND THE DIRECTION OF THE HYPOXIA RESPONSE. THE IMPORTANCE OF THIS CONTROL FOR TUMOR CELL SURVIVAL IS ILLUSTRATED BY THE INTRICATE REGULATION OF HIF ACTIVITY AT THE MRNA, PROTEIN AND EPIGENETIC LEVEL BY A COMPLEX NETWORK OF POSITIVE AND NEGATIVE FEEDBACK REGULATORS. WE PROPOSE THAT THESE FEEDBACK REGULATORS HELP TO FLEXIBLY ADJUST AND ADAPT HIF ACTIVATED RESPONSES TO THE FLUCTUATING OXYGEN CONCENTRATIONS WITHIN TUMORS DURING ACUTE AND CHRONIC HYPOXIA AND TO CURTAIL THE TUMOR-SUPPRESSING COMPONENTS OF THE HIF PATHWAY. MOREOVER, FEEDBACK REGULATION OF HIF INDUCES A SWITCH FROM HIF-1ALPHA TO HIF-2ALPHA DRIVEN RESPONSES UNDER CHRONIC HYPOXIA WHICH MAY HAVE ESSENTIAL FUNCTIONS IN THE REGULATION OF TUMOR CELL DIFFERENTIATION AND TUMOR STEM CELL MAINTENANCE. GIVEN THEIR CENTRAL ROLE IN CANCER BIOLOGY, HIF FEEDBACK REGULATORS MAY REPRESENT AN ATTRACTIVE AND NOVEL ANTI-TUMOR THERAPY TARGET TO OVERCOME CELL DEATH RESISTANCE IN TUMORS. 2010 20 2145 25 EPIGENETIC MAINTENANCE OF ACQUIRED GENE EXPRESSION PROGRAMS DURING MEMORY CD8 T CELL HOMEOSTASIS. MEMORY CD8 T CELLS HAVE A UNIQUE ABILITY TO PROVIDE LIFELONG IMMUNITY AGAINST PATHOGENS CONTAINING THEIR COGNATE EPITOPE. BECAUSE OF THEIR ABILITY TO PROVIDE LIFELONG PROTECTION, THE GENERATION OF MEMORY T CELLS IS NOW A MAJOR FOCUS FOR CURRENT VACCINATION OR ADOPTIVE CELL THERAPY APPROACHES TO TREAT CHRONIC VIRAL INFECTIONS AND CANCER. IT IS NOW CLEAR THAT MAINTENANCE OF MEMORY CD8 T CELLS OCCURS THROUGH A PROCESS OF ANTIGEN-INDEPENDENT HOMEOSTATIC PROLIFERATION, WHICH IS REGULATED IN PART BY THE GAMMA CHAIN CYTOKINES IL-7 AND IL-15. HERE, WE WILL DESCRIBE THE ROLE OF THESE CYTOKINES IN THE SURVIVAL AND SELF-RENEWAL OF MEMORY CD8 T CELLS. FURTHER, WE WILL DESCRIBE THE ROLE OF EPIGENETICS IN THE MAINTENANCE OF ACQUIRED FUNCTIONS AMONG MEMORY CD8 T CELLS DURING HOMEOSTATIC PROLIFERATION. 2018