1 373 115 AN EMERGING ROLE OF NEUTROPHILS AND NETOSIS IN CHRONIC INFLAMMATION AND FIBROSIS IN SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) AND ANCA-ASSOCIATED VASCULITIDES (AAV): IMPLICATIONS FOR THE PATHOGENESIS AND TREATMENT. NEUTROPHILS DERIVE FROM HEMATOPOIETIC STEM CELLS (HSCS) WITH SYSTEMIC INFLAMMATION DRIVING THEIR ACTIVATION AND DIFFERENTIATION TO MYELOID PROGENITORS TO ENSURE ENHANCED MYELOPOIESIS. EPIGENETIC REPROGRAMING AND RE-EDUCATION OF THESE HSCS PRODUCES NEUTROPHILS PRIMED TOWARDS ELIMINATION OF PATHOGENS AND INCREASED INFLAMMATORY RESPONSE. NEUTROPHILS -AN IMPORTANT COMPONENT OF ACUTE INFLAMMATION- ARE NOT PRESENT IN CHRONIC INFLAMMATORY TISSUES LEADING TO THE FALSE ASSUMPTION THAT THEY MAY NOT BE AS IMPORTANT FOR THE LATTER. ACTIVATED NEUTROPHILS MAY RELEASE NEUTROPHIL EXTRACELLULAR TRAPS (NETS) DURING A DISTINCT FORM OF CELL DEATH, NAMED NETOSIS; NETS ARE RICH IN BIOACTIVE MOLECULES THAT PROMOTE THROMBOSIS (INCLUDING ATHEROTHROMBOSIS), INFLAMMATION AND FIBROSIS. THUS, ALTHOUGH NEUTROPHILS MAY NOT BE PRESENT IN CHRONIC INFLAMMATORY LESIONS, THEIR REMNANTS MAY AMPLIFY THE INFLAMMATORY RESPONSE BEYOND THEIR SHORT LIFE-SPAN IN THE TISSUES. HEREIN, WE REVIEW CURRENT EVIDENCE SUPPORTING A ROLE OF NEUTROPHILS AND NETOSIS IN TISSUE INJURY AND DYSFUNCTION IN SYSTEMIC AUTOIMMUNITY USING AS DISEASE PARADIGMS SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) AND THE ANCA-ASSOCIATED VASCULITIDES (AAV). WE ALSO DISCUSS THE MECHANISMS INVOLVED AND THEIR POTENTIAL AS TARGETS FOR NOVEL THERAPY AND DRUG REPOSITIONING. 2019 2 1701 32 DYNAMIC IMMUNE/INFLAMMATION PRECISION MEDICINE: THE GOOD AND THE BAD INFLAMMATION IN INFECTION AND CANCER. NORMAL OR "GOOD" INFLAMMATION PROCESS STARTS FROM A LOCAL CELLULAR RESPONSE AGAINST INJURY OR ANY INFECTIOUS AGENT, WITH THE ACTIVATION OF NEUTROPHILS, MACROPHAGES, LANGERHANS CELLS, DENDRITIC CELLS, AND INNATE IMMUNE CELLS. CYTOKINES AND CHEMOKINES ARE PRODUCED TO AMPLIFY THE LOCAL INFLAMMATORY PROCESS FOLLOWED BY THE MIGRATION OF IMMUNE CELLS TO THE REGIONAL LYMPH NODES WHERE ADAPTIVE IMMUNE RESPONSE IS INITIATED. SYSTEMIC INFLAMMATION ENHANCES THE BIOLOGICAL RESPONSE TO MOBILIZE ADDITIONAL CELLS FROM CENTRAL AND PERIPHERAL IMMUNE/HEMATOPOIETIC SYSTEM. LOCAL MECHANISMS TO LIMIT INFLAMMATION ARE INITIATED AND LEAD TO HEALING. DURING THE NORMAL INFLAMMATORY PROCESS, THERE IS A BALANCE BETWEEN THE PRODUCTION OF INFLAMMATORY CHEMOKINES/CYTOKINES SUCH AS TUMOR NECROSIS FACTOR (TNF)-ALPHA, INTERLEUKIN (IL)-6 AND IL-1 AND THE PRODUCTION OF COMPOUNDS THAT LIMIT INFLAMMATION AND HAVE AN IMMUNE SUPPRESSIVE EFFECT, SUCH AS IL-10 AND TRANSFORMING FACTOR (TGF) BETA. IL-6 AND IL-6/SOLUBLE IL-6 RECEPTOR (R) COMPLEX STIMULATE LIVER CELLS TO PRODUCE INFLAMMATORY PROTEINS, WHICH REPRESENTS THE SYSTEMIC INFLAMMATION RESPONSE. THE MAGNITUDE AND THE DURATION OF THE SYSTEMIC INFLAMMATORY RESPONSE ARE LINKED TO THE CAUSE, UNDER GENETIC AND EPIGENETIC CONTROL. SIGNIFICANT INFLAMMATION AS SEEN IN SEPTIC SHOCK, IN SEVERE FORMS OF INFECTIONS OR IN CERTAIN ACTIVE CANCERS, REPRESENTS THE "BAD INFLAMMATION", CORRELATED WITH A POOR PROGNOSIS. IN ADDITION, THE PERSISTENCE OF A CHRONIC SMOLDERING INFLAMMATION MAY LEAD TO PATHOLOGICAL SITUATIONS WHICH ARE OBSERVED IN THE MAJORITY OF INFLAMMATORY, DEGENERATIVE, DYSMETABOLIC, OR DYSIMMUNE DISEASES AND CANCER. CHRONIC SMOLDERING INFLAMMATION IS A CROSS BETWEEN DIFFERENT PATHOLOGICAL SITUATIONS POSSIBLY LINKED. IN ADDITION, WITHIN THE TUMOR MICROENVIRONMENT, INFLAMMATORY PROCESS RESULTS FROM DIFFERENT CELLULAR MECHANISMS MODULATED BY METABOLIC AND VASCULAR CHANGES. ON THE CONTRARY, A LIMITED AND BALANCED INFLAMMATION INITIATES THE NORMAL IMMUNE RESPONSE, INCLUDING THE ADAPTIVE RESPONSE WHICH AMPLIFIES ANY IMMUNOTHERAPY, INCLUDING VACCINES. IMMUNE CHECKPOINT INHIBITORS AND CHIMERIC ANTIGEN RECEPTOR (CAR) T-CELLS ARE ASSOCIATED WITH CYTOKINE RELEASE SYNDROME, A CLINICAL RISK LEADING TO THE USE OF ANTI-CYTOKINE DRUGS. NOWADAYS, IT IS TIME TO MONITOR THE DYNAMIC INFLAMMATORY PROCESS FOR A BETTER IMMUNE PRECISION MEDICINE IN BOTH INFECTIONS AND CANCER. 2021 3 5993 26 TGFBETA PROMOTES FIBROSIS BY MYST1-DEPENDENT EPIGENETIC REGULATION OF AUTOPHAGY. ACTIVATION OF FIBROBLASTS IS ESSENTIAL FOR PHYSIOLOGICAL TISSUE REPAIR. UNCONTROLLED ACTIVATION OF FIBROBLASTS, HOWEVER, MAY LEAD TO TISSUE FIBROSIS WITH ORGAN DYSFUNCTION. ALTHOUGH SEVERAL PATHWAYS CAPABLE OF PROMOTING FIBROBLAST ACTIVATION AND TISSUE REPAIR HAVE BEEN IDENTIFIED, THEIR INTERPLAY IN THE CONTEXT OF CHRONIC FIBROTIC DISEASES REMAINS INCOMPLETELY UNDERSTOOD. HERE, WE PROVIDE EVIDENCE THAT TRANSFORMING GROWTH FACTOR-BETA (TGFBETA) ACTIVATES AUTOPHAGY BY AN EPIGENETIC MECHANISM TO AMPLIFY ITS PROFIBROTIC EFFECTS. TGFBETA INDUCES AUTOPHAGY IN FIBROTIC DISEASES BY SMAD3-DEPENDENT DOWNREGULATION OF THE H4K16 HISTONE ACETYLTRANSFERASE MYST1, WHICH REGULATES THE EXPRESSION OF CORE COMPONENTS OF THE AUTOPHAGY MACHINERY SUCH AS ATG7 AND BECLIN1. ACTIVATION OF AUTOPHAGY IN FIBROBLASTS PROMOTES COLLAGEN RELEASE AND IS BOTH, SUFFICIENT AND REQUIRED, TO INDUCE TISSUE FIBROSIS. FORCED EXPRESSION OF MYST1 ABROGATES THE STIMULATORY EFFECTS OF TGFBETA ON AUTOPHAGY AND RE-ESTABLISHES THE EPIGENETIC CONTROL OF AUTOPHAGY IN FIBROTIC CONDITIONS. INTERFERENCE WITH THE ABERRANT ACTIVATION OF AUTOPHAGY INHIBITS TGFBETA-INDUCED FIBROBLAST ACTIVATION AND AMELIORATES EXPERIMENTAL DERMAL AND PULMONARY FIBROSIS. THESE FINDINGS LINK UNCONTROLLED TGFBETA SIGNALING TO ABERRANT AUTOPHAGY AND DEREGULATED EPIGENETICS IN FIBROTIC DISEASES AND MAY CONTRIBUTE TO THE DEVELOPMENT OF THERAPEUTIC INTERVENTIONS IN FIBROTIC DISEASES. 2021 4 4376 21 MITOCHONDRIAL (DYS) FUNCTION IN INFLAMMAGING: DO MITOMIRS INFLUENCE THE ENERGETIC, OXIDATIVE, AND INFLAMMATORY STATUS OF SENESCENT CELLS? A RELEVANT FEATURE OF AGING IS CHRONIC LOW-GRADE INFLAMMATION, TERMED INFLAMMAGING, A KEY PROCESS PROMOTING THE DEVELOPMENT OF ALL MAJOR AGE-RELATED DISEASES. SENESCENT CELLS CAN ACQUIRE THE SENESCENCE-ASSOCIATED (SA) SECRETORY PHENOTYPE (SASP), CHARACTERIZED BY THE SECRETION OF PROINFLAMMATORY FACTORS FUELLING INFLAMMAGING. CELLULAR SENESCENCE IS ALSO ACCOMPANIED BY A DEEP RESHAPING OF MICRORNA EXPRESSION AND BY THE MODULATION OF MITOCHONDRIA ACTIVITY, BOTH MASTER REGULATORS OF THE SASP. HERE, WE SYNTHESIZE NOVEL FINDINGS REGARDING THE ROLE OF MITOCHONDRIA IN THE SASP AND IN THE INFLAMMAGING PROCESS AND PROPOSE A NETWORK LINKING NUCLEAR-ENCODED SA-MIRNAS TO MITOCHONDRIAL GENE REGULATION AND FUNCTION IN AGING CELLS. IN THIS CONCEPTUAL STRUCTURE, SA-MIRNAS CAN TRANSLOCATE TO MITOCHONDRIA (SA-MITOMIRS) AND MAY AFFECT THE ENERGETIC, OXIDATIVE, AND INFLAMMATORY STATUS OF SENESCENT CELLS. WE DISCUSS THE POTENTIAL ROLE OF SEVERAL OF SA-MITOMIRS (I.E., LET-7B, MIR-1, MIR-130A-3P, MIR-133A, MIR-146A-5P, MIR-181C-5P, AND MIR-378-5P), USING MIR-146A AS A PROOF-OF-PRINCIPLE MODEL. FINALLY, WE PROPOSE A COMPREHENSIVE, METABOLIC, AND EPIGENETIC VIEW OF THE SENESCENCE PROCESS, IN ORDER TO AMPLIFY THE RANGE OF POSSIBLE APPROACHES TO TARGET INFLAMMAGING, WITH THE ULTIMATE GOAL OF DECELERATING THE AGING RATE, POSTPONING OR BLUNTING THE DEVELOPMENT OF AGE-RELATED DISEASES. 2017 5 2305 25 EPIGENETIC REGULATION OF CC-CHEMOKINE LIGAND 2 IN NONRESOLVING INFLAMMATION. INFLAMMATION MEDIATED BY THE CROSSTALK BETWEEN LEUKOCYTES AND RESIDENT TISSUE CELLS IS CRUCIAL FOR THE MAINTENANCE OF HOMEOSTASIS. BECAUSE CHEMOKINE LIGANDS AND RECEPTORS, WHICH RECRUIT A VARIETY OF LEUKOCYTES, ARE WIDELY DISTRIBUTED AMONG TISSUES, IT IS IMPORTANT TO UNDERSTAND THE MECHANISMS REGULATING INFLAMMATORY DISEASE. CHEMOKINES SUCH AS CC-CHEMOKINE LIGAND 2 (CCL2) AMPLIFY AND MAINTAIN INFLAMMATION THROUGH CHEMOKINE-CYTOKINE NETWORKS AFTER THE RECRUITMENT OF CIRCULATING LEUKOCYTES. CHEMOKINE-DEPENDENT NONRESOLVING INFLAMMATION OCCURS IN THE PERIPHERAL AND CENTRAL NERVOUS SYSTEMS, AND UNDERLIES SEVERAL INTRACTABLE DISEASES, INCLUDING CANCER AND NEUROPATHIC PAIN. THE CHRONIC UPREGULATION OF CHEMOKINES IS OFTEN MEDIATED BY EPIGENETIC MECHANISMS CONSISTING OF DNA METHYLATION, HISTONE MODIFICATION, AND NUCLEOSOME POSITIONING. IN PARTICULAR, HISTONE ACETYLATION AND METHYLATION HAVE BEEN SHOWN TO PLAY IMPORTANT ROLES IN THE UPREGULATION OF CHEMOKINE EXPRESSION. IN ADDITION TO CCL2, SEVERAL OTHER CHEMOKINES STRONGLY CONTRIBUTE TO NEUROPATHIC PAIN THROUGH EPIGENETIC INDUCTION. CONSEQUENTLY, TARGETING EPIGENETIC CHANGES MAY HAVE THERAPEUTIC POTENTIAL FOR NONRESOLVING INFLAMMATORY DISEASES SUCH AS NEUROPATHIC PAIN. FURTHER RESEARCH INTO THE EPIGENETICS OF INFLAMMATORY DISEASES SHOULD PROMOTE THE DEVELOPMENT OF NOVEL AND EFFECTIVE TREATMENT STRATEGIES FOR INTRACTABLE INFLAMMATORY DISEASES. 2014 6 5179 27 PREGNANCY: AN UNDERUTILIZED WINDOW OF OPPORTUNITY TO IMPROVE LONG-TERM MATERNAL AND INFANT HEALTH-AN APPEAL FOR CONTINUOUS FAMILY CARE AND INTERDISCIPLINARY COMMUNICATION. PHYSIOLOGIC ADAPTATIONS DURING PREGNANCY UNMASK A WOMAN'S PREDISPOSITION TO DISEASES. COMPLICATIONS ARE INCREASINGLY PREDICTED BY FIRST-TRIMESTER ALGORITHMS, AMPLIFY A PRE-EXISTING MATERNAL PHENOTYPE AND ACCELERATE RISKS FOR CHRONIC DISEASES IN THE OFFSPRING UP TO ADULTHOOD (BARKER HYPOTHESIS). RECENT EVIDENCE SUGGESTS THAT VICE VERSA, PREGNANCY DISEASES ALSO INDICATE MATERNAL AND EVEN GRANDPARENT'S RISKS FOR CHRONIC DISEASES (REVERSE BARKER HYPOTHESIS). PUB-MED AND EMBASE WERE REVIEWED FOR MESH TERMS "FETAL PROGRAMMING" AND "PREGNANCY COMPLICATIONS COMBINED WITH MATERNAL DISEASE" UNTIL JANUARY 2017. STUDIES LINKING PREGNANCY COMPLICATIONS TO FUTURE CARDIOVASCULAR, METABOLIC, AND THROMBOTIC RISKS FOR MOTHER AND OFFSPRING WERE REVIEWED. WOMEN WITH A HISTORY OF MISCARRIAGE, FETAL GROWTH RESTRICTION, PREECLAMPSIA, PRETERM DELIVERY, OBESITY, EXCESSIVE GESTATIONAL WEIGHT GAIN, GESTATIONAL DIABETES, SUBFERTILITY, AND THROMBOPHILIA MORE FREQUENTLY DEMONSTRATE WITH ECHOCARDIOGRAPHIC ABNORMALITIES, HIGHER FASTING INSULIN, DEVIATING LIPIDS OR CLOTTING FACTORS AND SHOW DEFECTIVE ENDOTHELIAL FUNCTION. THROMBOPHILIA HINTS TO THROMBOTIC RISKS IN LATER LIFE. PREGNANCY ABNORMALITIES CORRELATE WITH FUTURE CARDIOVASCULAR AND METABOLIC COMPLICATIONS AND EARLIER MORTALITY. CONVERSELY, WOMEN WITH A NORMAL PREGNANCY HAVE LOWER RATES OF SUBSEQUENT DISEASES THAN THE GENERAL FEMALE POPULATION CREATING THE TERM: "PREGNANCY AS A WINDOW FOR FUTURE HEALTH." ALTHOUGH THE PLACENTA WORKS AS A GATEKEEPER, MANY PREGNANCY COMPLICATIONS MAY LEAD TO SICKNESS AND EARLIER DEATH IN LATER LIFE WHEN THE CHILD BECOMES AN ADULT. THE EPIGENETIC MECHANISMS AND THE MISMATCH BETWEEN PRE- AND POSTNATAL LIFE HAVE CREATED THE TERM "FETAL ORIGIN OF ADULT DISEASE." UP TO NOW, THE IMPACT OF CARDIOVASCULAR, METABOLIC, OR THROMBOTIC RISK PROFILES HAS BEEN INVESTIGATED SEPARATELY FOR MOTHER AND CHILD. IN THIS MANUSCRIPT, WE STRIVE TO ILLUSTRATE THE CONSEQUENCES FOR BOTH, FETUS AND MOTHER WITHIN A COHESIVE PERSPECTIVE AND THUS TRY TO DEMONSTRATE THE COMPLEX INTERRELATIONSHIP OF GENETICS AND EPIGENETICS FOR LONG-TERM HEALTH OF SOCIETIES AND FUTURE GENERATIONS. MATERNAL-FETAL MEDICINE SPECIALISTS SHOULD HAVE A KEY ROLE IN THE PREVENTION OF NON-COMMUNICABLE DISEASES BY IMPLEMENTING A FRAMEWORK FOR PATIENT CONSULTATION AND INTERDISCIPLINARY NETWORKS. HEALTH-CARE PROVIDERS AND POLICY MAKERS SHOULD INCREASINGLY INVEST IN A STRATIFIED PRIMARY PREVENTION AND FOLLOW-UP TO REDUCE THE INCREASING NUMBER OF MANIFEST CARDIOVASCULAR AND METABOLIC DISEASES AND TO PREVENT WASTE OF HEALTH-CARE RESOURCES. 2017 7 6302 26 THE PUTATIVE ROLE OF VIRUSES, BACTERIA, AND CHRONIC FUNGAL BIOTOXIN EXPOSURE IN THE GENESIS OF INTRACTABLE FATIGUE ACCOMPANIED BY COGNITIVE AND PHYSICAL DISABILITY. PATIENTS WHO PRESENT WITH SEVERE INTRACTABLE APPARENTLY IDIOPATHIC FATIGUE ACCOMPANIED BY PROFOUND PHYSICAL AND OR COGNITIVE DISABILITY PRESENT A SIGNIFICANT THERAPEUTIC CHALLENGE. THE EFFECT OF PSYCHOLOGICAL COUNSELING IS LIMITED, WITH SIGNIFICANT BUT VERY SLIGHT IMPROVEMENTS IN PSYCHOMETRIC MEASURES OF FATIGUE AND DISABILITY BUT NO IMPROVEMENT ON SCIENTIFIC MEASURES OF PHYSICAL IMPAIRMENT COMPARED TO CONTROLS. SIMILARLY, EXERCISE REGIMES EITHER PRODUCE SIGNIFICANT, BUT PRACTICALLY UNIMPORTANT, BENEFIT OR PROVOKE SYMPTOM EXACERBATION. MANY SUCH PATIENTS ARE AFFORDED THE EXCLUSIONARY, NON-SPECIFIC DIAGNOSIS OF CHRONIC FATIGUE SYNDROME IF RUDIMENTARY TESTING FAILS TO DISCOVER THE CAUSE OF THEIR SYMPTOMS. MORE SOPHISTICATED INVESTIGATIONS OFTEN REVEAL THE PRESENCE OF A RANGE OF PATHOGENS CAPABLE OF ESTABLISHING LIFE-LONG INFECTIONS WITH SOPHISTICATED IMMUNE EVASION STRATEGIES, INCLUDING PARVOVIRUSES, HHV6, VARIANTS OF EPSTEIN-BARR, CYTOMEGALOVIRUS, MYCOPLASMA, AND BORRELIA BURGDORFERI. OTHER PATIENTS HAVE A HISTORY OF CHRONIC FUNGAL OR OTHER BIOTOXIN EXPOSURE. HEREIN, WE EXPLAIN THE EPIGENETIC FACTORS THAT MAY RENDER SUCH INDIVIDUALS SUSCEPTIBLE TO THE CHRONIC PATHOLOGY INDUCED BY SUCH AGENTS, HOW SUCH AGENTS INDUCE PATHOLOGY, AND, INDEED, HOW SUCH PATHOLOGY CAN PERSIST AND EVEN AMPLIFY EVEN WHEN INFECTIONS HAVE CLEARED OR WHEN BIOTOXIN EXPOSURE HAS CEASED. THE PRESENCE OF ACTIVE, REACTIVATED, OR EVEN LATENT HERPES VIRUS COULD BE A POTENTIAL SOURCE OF INTRACTABLE FATIGUE ACCOMPANIED BY PROFOUND PHYSICAL AND OR COGNITIVE DISABILITY IN SOME PATIENTS, AND THE SAME MAY BE TRUE OF PERSISTENT PARVOVIRUS B12 AND MYCOPLASMA INFECTION. A HISTORY OF CHRONIC MOLD EXPOSURE IS A FEASIBLE EXPLANATION FOR SUCH SYMPTOMS, AS IS THE PRESENCE OF B. BURGDORFERI. THE COMPLEX TROPISM, LIFE CYCLES, GENETIC VARIABILITY, AND LOW TITER OF MANY OF THESE PATHOGENS MAKES THEIR DETECTION IN BLOOD A CHALLENGE. EXAMINATION OF LYMPHOID TISSUE OR CSF IN SUCH CIRCUMSTANCES MAY BE WARRANTED. 2016 8 6376 30 THE ROLE OF NEUTROPHILS IN TRAINED IMMUNITY. THE PRINCIPLE OF TRAINED IMMUNITY REPRESENTS INNATE IMMUNE MEMORY DUE TO SUSTAINED, MAINLY EPIGENETIC, CHANGES TRIGGERED BY ENDOGENOUS OR EXOGENOUS STIMULI IN BONE MARROW (BM) PROGENITORS (CENTRAL TRAINED IMMUNITY) AND THEIR INNATE IMMUNE CELL PROGENY, THEREBY TRIGGERING ELEVATED RESPONSIVENESS AGAINST SECONDARY STIMULI. BM PROGENITORS CAN RESPOND TO MICROBIAL AND STERILE SIGNALS, THEREBY POSSIBLY ACQUIRING TRAINED IMMUNITY-MEDIATED LONG-LASTING ALTERATIONS THAT MAY SHAPE THE FATE AND FUNCTION OF THEIR PROGENY, FOR EXAMPLE, NEUTROPHILS. NEUTROPHILS, THE MOST ABUNDANT INNATE IMMUNE CELL POPULATION, ARE PRODUCED IN THE BM FROM COMMITTED PROGENITOR CELLS IN A PROCESS DESIGNATED GRANULOPOIESIS. NEUTROPHILS ARE THE FIRST RESPONDERS AGAINST INFECTIOUS OR INFLAMMATORY CHALLENGES AND HAVE VERSATILE FUNCTIONS IN IMMUNITY. TOGETHER WITH OTHER INNATE IMMUNE CELLS, NEUTROPHILS ARE EFFECTORS OF PERIPHERAL TRAINED IMMUNITY. HOWEVER, GIVEN THE SHORT LIFETIME OF NEUTROPHILS, THEIR ABILITY TO ACQUIRE IMMUNOLOGICAL MEMORY MAY LIE IN THE CENTRAL TRAINING OF THEIR BM PROGENITORS RESULTING IN GENERATION OF REPROGRAMMED, THAT IS, "TRAINED", NEUTROPHILS. ALTHOUGH TRAINED IMMUNITY MAY HAVE BENEFICIAL EFFECTS IN INFECTION OR CANCER, IT MAY ALSO MEDIATE DETRIMENTAL OUTCOMES IN CHRONIC INFLAMMATION. HERE, WE REVIEW THE EMERGING RESEARCH AREA OF TRAINED IMMUNITY WITH A PARTICULAR EMPHASIS ON THE ROLE OF NEUTROPHILS AND GRANULOPOIESIS. 2023 9 6452 23 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 5140 25 POTENTIAL REGULATORS OF THE SENESCENCE-ASSOCIATED SECRETORY PHENOTYPE DURING SENESCENCE AND AGING. SENESCENT CELLS EXPRESS AND SECRETE A VARIETY OF EXTRACELLULAR MODULATORS THAT INCLUDE CYTOKINES, CHEMOKINES, PROTEASES, GROWTH FACTORS, AND SOME ENZYMES ASSOCIATED WITH EXTRACELLULAR MATRIX REMODELING, DEFINED AS THE SENESCENCE-ASSOCIATED SECRETORY PHENOTYPE (SASP). SASP REINFORCES SENESCENT CELL CYCLE ARREST, STIMULATES AND RECRUITS IMMUNE CELLS FOR IMMUNE-MEDIATED CLEARANCE OF POTENTIALLY TUMORIGENIC CELLS, LIMITS OR INDUCES FIBROSIS, AND PROMOTES WOUND HEALING AND TISSUE REGENERATION. ON THE OTHER HAND, SASP MEDIATES CHRONIC INFLAMMATION LEADING TO THE DESTRUCTION OF TISSUE STRUCTURE AND FUNCTION AND STIMULATING THE GROWTH AND SURVIVAL OF TUMOR CELLS. SASP IS HIGHLY HETEROGENEOUS AND THE ROLE OF SASP DEPENDS ON THE CONTEXT. THE REGULATION OF SASP OCCURS AT MULTIPLE LEVELS INCLUDING CHROMATIN REMODELING, TRANSCRIPTION, MRNA TRANSLATION, INTRACELLULAR TRAFFICKING, AND SECRETION. SEVERAL SASP MODULATORS HAVE ALREADY BEEN IDENTIFIED SETTING THE STAGE FOR FUTURE RESEARCH ON THEIR CLINICAL APPLICATIONS. IN THIS REVIEW, WE SUMMARIZE IN DETAIL THE POTENTIAL SIGNALING PATHWAYS THAT TRIGGER AND REGULATE SASP PRODUCTION DURING AGING AND SENESCENCE. 2022 11 6502 30 TRAINED IMMUNITY: LONG-TERM ADAPTATION IN INNATE IMMUNE RESPONSES. ADAPTIVE IMMUNE RESPONSES ARE CHARACTERIZED BY ANTIGEN SPECIFICITY AND INDUCTION OF LIFELONG IMMUNOLOGIC MEMORY. RECENTLY, IT HAS BEEN REPORTED THAT INNATE IMMUNE CELLS CAN ALSO BUILD IMMUNE MEMORY CHARACTERISTICS-A PROCESS TERMED TRAINED IMMUNITY. TRAINED IMMUNITY DESCRIBES THE PERSISTENT HYPERRESPONSIVE PHENOTYPE THAT INNATE IMMUNE CELLS CAN DEVELOP AFTER BRIEF STIMULATION. PATHOGENIC STIMULI SUCH AS MICROORGANISMS, AND ALSO ENDOGENOUS MOLECULES INCLUDING URIC ACID, OXIDIZED LDL (LOW-DENSITY LIPOPROTEIN), AND CATECHOLAMINES, ARE CAPABLE OF INDUCING MEMORY IN MONOCYTES AND MACROPHAGES. WHILE TRAINED IMMUNITY PROVIDES FAVORABLE CROSS-PROTECTION IN THE CONTEXT OF INFECTIOUS DISEASES, THE HEIGHTENED IMMUNE RESPONSE CAN BE MALADAPTIVE IN DISEASES DRIVEN BY CHRONIC SYSTEMIC INFLAMMATION, SUCH AS ATHEROSCLEROSIS. TRAINED IMMUNITY IS MAINTAINED BY DISTINCT EPIGENETIC AND METABOLIC MECHANISMS AND PERSISTS FOR AT LEAST SEVERAL MONTHS IN VIVO DUE TO REPROGRAMMING OF MYELOID PROGENITOR CELLS. ADDITIONALLY, CERTAIN NONIMMUNE CELLS ARE ALSO FOUND TO EXHIBIT TRAINED IMMUNITY CHARACTERISTICS. THUS, TRAINED IMMUNITY PRESENTS AN EXCITING FRAMEWORK TO DEVELOP NEW APPROACHES TO VACCINATION AND ALSO NOVEL PHARMACOLOGICAL TARGETS IN THE TREATMENT OF INFLAMMATORY DISEASES. 2021 12 2342 25 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 13 6498 33 TRAINED IMMUNITY IN MONOCYTE/MACROPHAGE: NOVEL MECHANISM OF PHYTOCHEMICALS IN THE TREATMENT OF ATHEROSCLEROTIC CARDIOVASCULAR DISEASE. ATHEROSCLEROSIS (AS) IS THE PATHOLOGY OF ATHEROSCLEROTIC CARDIOVASCULAR DISEASES (ASCVD), CHARACTERIZED BY PERSISTENT CHRONIC INFLAMMATION IN THE VESSEL WALL, IN WHICH MONOCYTES/MACROPHAGES PLAY A KEY ROLE. IT HAS BEEN REPORTED THAT INNATE IMMUNE SYSTEM CELLS CAN ASSUME A PERSISTENT PROINFLAMMATORY STATE AFTER SHORT STIMULATION WITH ENDOGENOUS ATHEROGENIC STIMULI. THE PATHOGENESIS OF AS CAN BE INFLUENCED BY THIS PERSISTENT HYPERACTIVATION OF THE INNATE IMMUNE SYSTEM, WHICH IS TERMED TRAINED IMMUNITY. TRAINED IMMUNITY HAS ALSO BEEN IMPLICATED AS A KEY PATHOLOGICAL MECHANISM, LEADING TO PERSISTENT CHRONIC INFLAMMATION IN AS. TRAINED IMMUNITY IS MEDIATED VIA EPIGENETIC AND METABOLIC REPROGRAMMING AND OCCURS IN MATURE INNATE IMMUNE CELLS AND THEIR BONE MARROW PROGENITORS. NATURAL PRODUCTS ARE PROMISING CANDIDATES FOR NOVEL PHARMACOLOGICAL AGENTS THAT CAN BE USED TO PREVENT OR TREAT CARDIOVASCULAR DISEASES (CVD). A VARIETY OF NATURAL PRODUCTS AND AGENTS EXHIBITING ANTIATHEROSCLEROTIC ABILITIES HAVE BEEN REPORTED TO POTENTIALLY INTERFERE WITH THE PHARMACOLOGICAL TARGETS OF TRAINED IMMUNITY. THIS REVIEW DESCRIBES IN AS MUCH DETAIL AS POSSIBLE THE MECHANISMS INVOLVED IN TRAINED IMMUNITY AND HOW PHYTOCHEMICALS OF THIS PROCESS INHIBIT AS BY AFFECTING TRAINED MONOCYTES/MACROPHAGES. 2023 14 4380 35 MITOCHONDRIAL DYSFUNCTION AND OXIDATIVE STRESS IN RHEUMATOID ARTHRITIS. CONTROL OF EXCESSIVE MITOCHONDRIAL OXIDATIVE STRESS COULD PROVIDE NEW TARGETS FOR BOTH PREVENTIVE AND THERAPEUTIC INTERVENTIONS IN THE TREATMENT OF CHRONIC INFLAMMATION OR ANY PATHOLOGY THAT DEVELOPS UNDER AN INFLAMMATORY SCENARIO, SUCH AS RHEUMATOID ARTHRITIS (RA). INCREASING EVIDENCE HAS DEMONSTRATED THE ROLE OF MITOCHONDRIAL ALTERATIONS IN AUTOIMMUNE DISEASES MAINLY DUE TO THE INTERPLAY BETWEEN METABOLISM AND INNATE IMMUNITY, BUT ALSO IN THE MODULATION OF INFLAMMATORY RESPONSE OF RESIDENT CELLS, SUCH AS SYNOVIOCYTES. THUS, MITOCHONDRIAL DYSFUNCTION DERIVED FROM SEVERAL DANGER SIGNALS COULD ACTIVATE TRICARBOXYLIC ACID (TCA) DISRUPTION, THEREBY FAVORING A VICIOUS CYCLE OF OXIDATIVE/MITOCHONDRIAL STRESS. MITOCHONDRIAL DYSFUNCTION CAN ACT THROUGH MODULATING INNATE IMMUNITY VIA REDOX-SENSITIVE INFLAMMATORY PATHWAYS OR DIRECT ACTIVATION OF THE INFLAMMASOME. BESIDES, MITOCHONDRIA ALSO HAVE A CENTRAL ROLE IN REGULATING CELL DEATH, WHICH IS DEEPLY ALTERED IN RA. ADDITIONALLY, MULTIPLE EVIDENCE SUGGESTS THAT PATHOLOGICAL PROCESSES IN RA CAN BE SHAPED BY EPIGENETIC MECHANISMS AND THAT IN TURN, MITOCHONDRIA ARE INVOLVED IN EPIGENETIC REGULATION. FINALLY, WE WILL DISCUSS ABOUT THE INVOLVEMENT OF SOME DIETARY COMPONENTS IN THE ONSET AND PROGRESSION OF RA. 2022 15 4964 30 PATHOGENETIC AND CLINICAL ASPECTS OF ANTI-NEUTROPHIL CYTOPLASMIC AUTOANTIBODY-ASSOCIATED VASCULITIDES. ANTI-NEUTROPHIL CYTOPLASMIC AUTOANTIBODIES (ANCA) TARGETING PROTEINASE 3 (PR3) AND MYELOPEROXIDASE EXPRESSED BY INNATE IMMUNE CELLS (NEUTROPHILS AND MONOCYTES) ARE SALIENT DIAGNOSTIC AND PATHOGENIC FEATURES OF SMALL VESSEL VASCULITIS, COMPRISING GRANULOMATOSIS WITH POLYANGIITIS (GPA), MICROSCOPIC POLYANGIITIS, AND EOSINOPHILIC GPA. GENETIC STUDIES SUGGEST THAT ANCA-ASSOCIATED VASCULITIDES (AAV) CONSTITUTE SEPARATE DISEASES, WHICH SHARE COMMON IMMUNOLOGICAL AND PATHOLOGICAL FEATURES, BUT ARE OTHERWISE HETEROGENEOUS. THE SUCCESSFUL THERAPEUTIC USE OF ANTI-CD20 ANTIBODIES EMPHASIZES THE PROMINENT ROLE OF ANCA AND POSSIBLY OTHER AUTOANTIBODIES IN THE PATHOGENESIS OF AAV. HOWEVER, TO ELUCIDATE CAUSAL EFFECTS IN AAV, A BETTER UNDERSTANDING OF THE COMPLEX INTERPLAY LEADING TO THE EMERGENCE OF B LYMPHOCYTES THAT PRODUCE PATHOGENIC ANCA REMAINS A CHALLENGE. DIFFERENT SCENARIOS SEEM POSSIBLE; E.G., THE BREAK OF TOLERANCE INDUCED BY A SHIFT FROM NON-PATHOGENIC TOWARD PATHOGENIC AUTOANTIGEN EPITOPES IN INFLAMED TISSUE. THIS REVIEW GIVES A BRIEF OVERVIEW ON CURRENT KNOWLEDGE ABOUT GENETIC AND EPIGENETIC FACTORS, BARRIER DYSFUNCTION AND CHRONIC NON-RESOLVING INFLAMMATION, NECRO-INFLAMMATORY AUTO-AMPLIFICATION OF CELLULAR DEATH AND INFLAMMATION, ALTERED AUTOANTIGEN PRESENTATION, ALTERNATIVE COMPLEMENT PATHWAY ACTIVATION, ALTERATIONS WITHIN PERIPHERAL AND INFLAMED TISSUE-RESIDING T- AND B-CELL POPULATIONS, ECTOPIC LYMPHOID TISSUE NEOFORMATION, THE CHARACTERIZATION OF PR3-SPECIFIC T-CELLS, PROPERTIES OF ANCA, LINKS BETWEEN AUTOIMMUNE DISEASE AND INFECTION-TRIGGERED PATHOLOGY, AND ANIMAL MODELS IN AAV. 2018 16 3734 31 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 17 1310 22 DEFINING TRAINED IMMUNITY AND ITS ROLE IN HEALTH AND DISEASE. IMMUNE MEMORY IS A DEFINING FEATURE OF THE ACQUIRED IMMUNE SYSTEM, BUT ACTIVATION OF THE INNATE IMMUNE SYSTEM CAN ALSO RESULT IN ENHANCED RESPONSIVENESS TO SUBSEQUENT TRIGGERS. THIS PROCESS HAS BEEN TERMED 'TRAINED IMMUNITY', A DE FACTO INNATE IMMUNE MEMORY. RESEARCH IN THE PAST DECADE HAS POINTED TO THE BROAD BENEFITS OF TRAINED IMMUNITY FOR HOST DEFENCE BUT HAS ALSO SUGGESTED POTENTIALLY DETRIMENTAL OUTCOMES IN IMMUNE-MEDIATED AND CHRONIC INFLAMMATORY DISEASES. HERE WE DEFINE 'TRAINED IMMUNITY' AS A BIOLOGICAL PROCESS AND DISCUSS THE INNATE STIMULI AND THE EPIGENETIC AND METABOLIC REPROGRAMMING EVENTS THAT SHAPE THE INDUCTION OF TRAINED IMMUNITY. 2020 18 5726 23 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 19 6504 35 TRAINED INNATE IMMUNITY AND ITS IMPLICATIONS FOR MUCOSAL IMMUNITY AND INFLAMMATION. THE LONG-STANDING DOGMA THAT IMMUNOLOGICAL MEMORY IS THE EXCLUSIVE PREROGATIVE OF THE ADAPTIVE IMMUNE SYSTEM HAS BEEN CHALLENGED BY EMERGING EVIDENCE THAT INNATE IMMUNITY CAN ALSO MAINTAIN MEMORY OF PAST EVENTS. SUCH IMMUNOLOGICAL IMPRINTING TAKES TWO FORMS, TRAINED INNATE IMMUNITY AND TOLERANCE. TRAINED IMMUNITY INVOLVES METABOLIC AND EPIGENETIC ADAPTATIONS IN INNATE IMMUNE CELLS AND THEIR PROGENITORS IN THE BONE MARROW UPON EXPOSURE TO CERTAIN MICROBIAL AND/OR INFLAMMATORY STIMULI SO THAT THE "TRAINED" CELLS WOULD BE POISED TO RESPOND MUCH FASTER AND STRONGER TO A SUBSEQUENT CHALLENGE (E.G., A NEW INFECTION THAT IS NOT NECESSARILY THE SAME AS THE EARLIER ONE). CONVERSELY, TOLERANCE LEADS TO ATTENUATED IMMUNE RESPONSES TO SECONDARY STIMULI. THIS REVIEW FOCUSES ON TRAINED IMMUNITY AND DISCUSSES EVIDENCE FOR ITS EXISTENCE FROM LOWER ORGANISMS TO HUMANS, ITS MECHANISTIC UNDERPINNINGS, AND ITS TRANSLATIONAL RAMIFICATIONS. ALTHOUGH TRAINED IMMUNITY CAN BE CONSIDERED AS AN EVOLUTIONARILY CONSERVED BENEFICIAL RESPONSE AGAINST REINFECTIONS, IN THE SETTING OF MODERN SOCIETIES WITH HIGH PREVALENCE OF CHRONIC MUCOSAL AND SYSTEMIC INFLAMMATORY DISEASES, TRAINED IMMUNITY COULD ALSO PROMOTE MALADAPTIVE IMMUNE RESPONSES THAT AGGRAVATE PATHOLOGY. THUS, DEPENDING ON CONTEXT, INNATE IMMUNE MEMORY COULD BE THERAPEUTICALLY MANIPULATED USING DEFINED AGONISTS TO EITHER PROMOTE INNATE IMMUNE RESPONSES (PARTICULARLY USEFUL FOR THE TREATMENT OF INFECTIONS OR CHEMOTHERAPY-INDUCED MYELOSUPPRESSION) OR SUPPRESS EXCESSIVE INFLAMMATION IN INFLAMMATORY AND AUTOIMMUNE DISEASES. 2019 20 6503 23 TRAINED IMMUNITY: REPROGRAMMING INNATE IMMUNITY IN HEALTH AND DISEASE. TRADITIONALLY, THE INNATE AND ADAPTIVE IMMUNE SYSTEMS ARE DIFFERENTIATED BY THEIR SPECIFICITY AND MEMORY CAPACITY. IN RECENT YEARS, HOWEVER, THIS PARADIGM HAS SHIFTED: CELLS OF THE INNATE IMMUNE SYSTEM APPEAR TO BE ABLE TO GAIN MEMORY CHARACTERISTICS AFTER TRANSIENT STIMULATION, RESULTING IN AN ENHANCED RESPONSE UPON SECONDARY CHALLENGE. THIS PHENOMENON HAS BEEN CALLED TRAINED IMMUNITY. TRAINED IMMUNITY IS CHARACTERIZED BY NONSPECIFIC INCREASED RESPONSIVENESS, MEDIATED VIA EXTENSIVE METABOLIC AND EPIGENETIC REPROGRAMMING. TRAINED IMMUNITY EXPLAINS THE HETEROLOGOUS EFFECTS OF VACCINES, WHICH RESULT IN INCREASED PROTECTION AGAINST SECONDARY INFECTIONS. HOWEVER, IN CHRONIC INFLAMMATORY CONDITIONS, TRAINED IMMUNITY CAN INDUCE MALADAPTIVE EFFECTS AND CONTRIBUTE TO HYPERINFLAMMATION AND PROGRESSION OF CARDIOVASCULAR DISEASE, AUTOINFLAMMATORY SYNDROMES, AND NEUROINFLAMMATION. IN THIS REVIEW WE SUMMARIZE THE CURRENT STATE OF THE FIELD OF TRAINED IMMUNITY, ITS MECHANISMS, AND ITS ROLES IN BOTH HEALTH AND DISEASE. 2021