1 6883 105 [RESOLUTION OF INFLAMMATION--PHARMACOLOGICAL ASPECTS]. INFLAMMATION IS A FUNDAMENTAL BIOLOGIC PROCESS EVOLUTIONALLY PRESERVED BY A GERM LINE CODE. THE INTERPLAY OF THE EPIGENETIC WITH THE ENVIRONMENT DIRECTS THE CODE TO TEMPORALLY DISTINCT INFLAMMATORY RESPONSES, WHICH CAN BE ACUTE OR CHRONIC. THE AIM OF THIS STUDY IS TO PRESENT NEW ASPECTS REGARDING THE RESOLUTION OF INFLAMMATION. ACUTE INFLAMMATION NORMALLY RESOLVES BY MECHANISMS STILL SOMEWHAT ELUSIVE. CURRENT EVIDENCE SUGGESTS THAT AN ACTIVE COORDINATED PROGRAM INITIATED THE FIRST FEW HOURS AFTER THE INFLAMMATORY RESPONSE BEGINS AND ITS FAILURE LEAD TO CHRONIC INFLAMMATION. THIS PROCESS IS ESSENTIAL FOR APPROPRIATE HOST RESPONSES, TISSUE PROTECTION AND THE RETURN TO HOMEOSTASIS. PROSTAGLANDINS AND LEUKOTRIENES ARE LIPID MEDIATORS THAT PLAY IMPORTANT ROLES IN HOST DEFENSE AND ACUTE INFLAMMATION. GRANULOCYTES PROMOTE THE SWITCH OF ARACHIDONIC ACID-DERIVED PROSTAGLANDINS AND LEUKOTRIENES TO LIPOXINS, ACTIVE ANTIINFLAMMATORY AND PRO-RESOLUTION MEDIATORS. THE APOPTOSIS OF THE NEUTROPHILS COINCIDES WITH THE BIOSYNTHESIS OF RESOLVINS AND PROTECTINS FROM OMEGA-3 POLYUNSATURATED FATTY ACIDS AND RELEASES ANTI-INFLAMMATORY AND REPARATIVE CYTOKINES. THIS INFORMATION COULD LEAD TO NEW TREATMENTS FOR INFLAMMATORY DISEASES. 2011 2 5469 37 RESOLUTION OF INFLAMMATION AS A NOVEL CHEMOPREVENTIVE STRATEGY. ACUTE INFLAMMATION, A PHYSIOLOGIC RESPONSE TO PROTECT CELLS FROM MICROBIAL INFECTION AND OTHER NOXIOUS STIMULI, IS AUTOMATICALLY TERMINATED BY ENDOGENOUS ANTI-INFLAMMATORY AND PRO-RESOLVING MEDIATORS TO RESTORE HOMEOSTATIC CONDITIONS. HOWEVER, IF TIMELY RESOLUTION OF INFLAMMATION IS FAILED, INFLAMMATION PERSISTS AND CAN PROGRESS TO A CHRONIC INFLAMMATION WHICH HAS LONG BEEN THOUGHT AS A PREDISPOSING FACTOR TO CARCINOGENESIS. EXCESSIVE AND PATHOLOGIC INFLAMMATION CAUSES DNA DAMAGE, GENOMIC INSTABILITY, EPIGENETIC DYSREGULATION, AND ALTERATION OF INTRACELLULAR SIGNALING, ALL OF WHICH ARE INVOLVED IN NEOPLASTIC TRANSFORMATION. TO PREVENT CHRONIC INFLAMMATION AND RESULTING INFLAMMATION-PROMOTED CANCER DEVELOPMENT, UNDERSTANDING THE PROCESS THAT RESOLVES INFLAMMATION IS ESSENTIAL. RESOLUTION OF INFLAMMATION IS AN ACTIVE COORDINATED PROCESS REGULATED BY DISTINCT ANTI-INFLAMMATORY AND PRO-RESOLVING ENDOGENOUS LIPID MEDIATORS, SUCH AS RESOLVINS AND LIPOXINS. THE ROLE OF PRO-INFLAMMATORY SIGNALING IN CARCINOGENESIS HAS BECOME MORE AND MORE EVIDENT AND WELL CHARACTERIZED, BUT THE POTENTIAL ROLE OF PRO-RESOLVING MEDIATORS IN CANCER PREVENTION REMAINS STILL ELUSIVE. IN SEARCHING FOR AN EFFICACIOUS WAY TO PREVENT CHRONIC INFLAMMATION-ASSOCIATED CANCER, THE PRO-RESOLVING SIGNAL TRANSDUCTION PATHWAYS AND THEIR REGULATORS SHOULD BE UNRAVELED. 2013 3 2525 26 EPIGENETICS AND TRAINED IMMUNITY. SIGNIFICANCE: A GROWING BODY OF CLINICAL AND EXPERIMENTAL EVIDENCE HAS CHALLENGED THE TRADITIONAL UNDERSTANDING THAT ONLY THE ADAPTIVE IMMUNE SYSTEM CAN MOUNT IMMUNOLOGICAL MEMORY. RECENT FINDINGS DESCRIBE THE ADAPTIVE CHARACTERISTICS OF THE INNATE IMMUNE SYSTEM, UNDERSCORED BY ITS ABILITY TO REMEMBER ANTECEDENT FOREIGN ENCOUNTERS AND RESPOND IN A NONSPECIFIC SENSITIZED MANNER TO REINFECTION. THIS HAS BEEN TERMED TRAINED INNATE IMMUNITY. ALTHOUGH BENEFICIAL IN THE CONTEXT OF RECURRENT INFECTIONS, THIS MIGHT ACTUALLY CONTRIBUTE TO CHRONIC IMMUNE-MEDIATED DISEASES, SUCH AS ATHEROSCLEROSIS. RECENT ADVANCES: IN LINE WITH ITS PROPOSED ROLE IN SUSTAINING CELLULAR MEMORIES, EPIGENETIC REPROGRAMMING HAS EMERGED AS A CRITICAL DETERMINANT OF TRAINED IMMUNITY. RECENT TECHNOLOGICAL AND COMPUTATIONAL ADVANCES THAT IMPROVE UNBIASED ACQUISITION OF EPIGENOMIC PROFILES HAVE SIGNIFICANTLY ENHANCED OUR APPRECIATION FOR THE COMPLEXITIES OF CHROMATIN ARCHITECTURE IN THE CONTEXTS OF DIVERSE IMMUNOLOGICAL CHALLENGES. CRITICAL ISSUES: KEY TO RESOLVING THE DISTINCT CHROMATIN SIGNATURES OF INNATE IMMUNE MEMORY IS A COMPREHENSIVE UNDERSTANDING OF THE PRECISE PHYSIOLOGICAL TARGETS OF REGULATORY PROTEINS THAT RECOGNIZE, DEPOSIT, AND REMOVE CHEMICAL MODIFICATIONS FROM CHROMATIN AS WELL AS OTHER GENE-REGULATING FACTORS. DRAWING FROM A RAPIDLY EXPANDING COMPENDIUM OF EXPERIMENTAL AND CLINICAL STUDIES, THIS REVIEW DETAILS A CURRENT PERSPECTIVE OF THE EPIGENETIC PATHWAYS THAT SUPPORT THE ADAPTED PHENOTYPES OF MONOCYTES AND MACROPHAGES. FUTURE DIRECTIONS: WE EXPLORE FUTURE STRATEGIES THAT ARE AIMED AT EXPLOITING THE MECHANISM OF TRAINED IMMUNITY TO IMPROVE THE PREVENTION AND TREATMENT OF INFECTIONS AND IMMUNE-MEDIATED CHRONIC DISORDERS. 2018 4 6504 30 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 5 4977 41 PATHOPHYSIOLOGY AND EVOLUTIONARY ASPECTS OF DIETARY FATS AND LONG-CHAIN POLYUNSATURATED FATTY ACIDS ACROSS THE LIFE CYCLE. DIETARY FAT IS OUR SECOND MOST IMPORTANT ENERGY-PRODUCING MACRONUTRIENT. IT ALSO CONTAINS FATTY ACIDS AND VITAMINS ESSENTIAL FOR GROWTH, DEVELOPMENT, AND MAINTENANCE OF GOOD HEALTH. DIETARY FAT QUANTITY AND QUALITY HAVE BEEN SUBJECT TO TREMENDOUS CHANGE OVER THE PAST 10,000 YEARS. THIS HAS, TOGETHER WITH OTHER MAN-MADE CHANGES IN OUR ENVIRONMENT, CAUSED A CONFLICT WITH OUR SLOWLY ADAPTING GENOME THAT IS IMPLICATED IN "TYPICALLY WESTERN" DISEASES. RATHER THAN REDUCING OUR LIFE EXPECTANCY, THESE DISEASES NOTABLY DIMINISH OUR NUMBER OF YEARS IN HEALTH. IMPORTANT CHANGES IN DIETARY FAT QUALITY ARE THE INCREASED INTAKES OF CERTAIN SATURATED FATTY ACIDS (SAFA) AND LINOLEIC ACID (LA), INTRODUCTION OF INDUSTRIALLY PRODUCED TRANS FATTY ACIDS, AND REDUCED INTAKES OF OMEGA3 FATTY ACIDS, NOTABLY ALPHA-LINOLENIC ACID (ALA) FROM VEGETABLE SOURCES AND EICOSAPENTAENOIC ACID (EPA) AND DOCOSAHEXAENOIC ACID (DHA) FROM FISH. THE PATHOPHYSIOLOGICAL EFFECTS OF THESE CHANGES ARE DIVERSE, BUT ARE INCREASINGLY ASCRIBED TO INDUCTION OF A PROINFLAMMATORY STATE THAT PROGRESSES EASILY TO CHRONIC LOW-GRADE INFLAMMATION. THE LATTER MIGHT AFFECT VIRTUALLY ALL ORGANS AND SYSTEMS, POSSIBLY BEGINNING AT CONCEPTION, AND POSSIBLY EVEN PRIOR TO GAMETOGENESIS THROUGH EPIGENETIC ALTERATIONS. LOW-GRADE INFLAMMATION MIGHT BE A COMMON DENOMINATOR OF THE METABOLIC SYNDROME AND ITS SEQUELAE (E.G., CORONARY ARTERY DISEASE (CAD), DIABETES MELLITUS TYPE 2, SOME TYPES OF CANCER, AND PREGNANCY COMPLICATIONS), SOME PSYCHIATRIC DISEASES (E.G., MAJOR AND POSTPARTUM DEPRESSION, SCHIZOPHRENIA, AND AUTISM), AND NEURODEGENERATIVE DISEASES (E.G., ALZHEIMER'S DISEASE, PARKINSON'S DISEASE). THE LONG-CHAIN POLYUNSATURATED FATTY ACIDS (LCPUFA) ARACHIDONIC ACID (AA), EPA, AND DHA ARE INTIMATELY RELATED TO THE INITIATION AND RESOLUTION OF INFLAMMATORY RESPONSES. THE CURRENT BALANCE BETWEEN AA AND EPA + DHA IS HOWEVER DISTURBED BY THE DOMINANCE OF AA, WHICH ORIGINATES FROM THE DIET OR SYNTHESIS FROM LA. LCPUFA ARE TOGETHER WITH THEIR HIGHLY POTENT METABOLITES (PROSTAGLANDINS, THROMBOXANES, LEUKOTRIENES, RESOLVINS, AND (NEURO)PROTECTINS) INVOLVED IN THE FUNCTIONING OF MEMBRANE-BOUND RECEPTORS, TRANSPORTERS, ION CHANNELS, AND ENZYMES, AND ALSO IN SIGNAL TRANSDUCTION AND GENE EXPRESSION. AMONG THEIR MANY TARGETS ARE NUCLEAR RECEPTORS WHICH, UPON LIGATION WITH LCPUFA AND THEIR METABOLITES, FUNCTION AS TRANSCRIPTION FACTORS OF A VARIETY OF GENES FUNCTIONING IN MANY PATHWAYS. FOR INSTANCE, THE TARGETED PEROXISOME PROLIFERATORS-ACTIVATED RECEPTORS (PPARS) ARE STRATEGIC INTERMEDIATES IN THE COORDINATED EXPRESSION OF PROTEINS WITH FUNCTIONS IN, FOR EXAMPLE, LIPID AND GLUCOSE HOMEOSTASIS AND INFLAMMATORY REACTIONS. MANY INTERVENTIONS HAVE BEEN CONDUCTED WITH LCPUFA, ESPECIALLY EPA AND DHA, AIMING AT PRIMARY AND SECONDARY CAD PREVENTIONS, IMPROVEMENT OF FETAL AND NEWBORN (BRAIN) DEVELOPMENT BY SUPPLEMENTATION DURING PREGNANCY OR EARLY POSTNATAL LIFE, AND IN PSYCHIATRIC DISEASES. CONSENSUS HAS BEEN REACHED THAT THOSE IN CAD AND DEPRESSION ARE POSITIVE, ALTHOUGH MORE LARGE-SCALE TRIALS ARE NEEDED. MANY RECOMMENDATIONS FOR THE INTAKES OF SATURATED FAT, TRANS FAT AND EPA + DHA HAVE BEEN ISSUED, NOTABLY FOR CAD PREVENTION, AND ALSO FOR EPA + DHA INTAKES BY PREGNANT WOMEN AND FOR AA, EPA, AND DHA INTAKES BY NEWBORNS. THE ULTIMATE GOAL MIGHT, HOWEVER, BE TO RETURN TO THE FAT QUALITY OF OUR ANCIENT DIET ON WHICH OUR GENES HAVE EVOLVED DURING THE PAST MILLION YEARS OF EVOLUTION, WHILE THIS ACTUALLY APPLIES FOR OUR ENTIRE DIETARY COMPOSITION AND LIFESTYLE, AS TRANSLATED TO THE CULTURE OF THE CURRENT SOCIETY. 2010 6 4037 26 MACROPHAGE IMMUNOMETABOLISM AND INFLAMMAGING: ROLES OF MITOCHONDRIAL DYSFUNCTION, CELLULAR SENESCENCE, CD38, AND NAD. AGING IS A COMPLEX PROCESS THAT INVOLVES DYSFUNCTION ON MULTIPLE LEVELS, ALL OF WHICH SEEM TO CONVERGE ON INFLAMMATION. MACROPHAGES ARE INTIMATELY INVOLVED IN INITIATING AND RESOLVING INFLAMMATION, AND THEIR DYSREGULATION WITH AGE IS A PRIMARY CONTRIBUTOR TO INFLAMMAGING-A STATE OF CHRONIC, LOW-GRADE INFLAMMATION THAT DEVELOPS DURING AGING. AMONG THE AGE-RELATED CHANGES THAT OCCUR TO MACROPHAGES ARE A HEIGHTENED STATE OF BASAL INFLAMMATION AND DIMINISHED OR HYPERACTIVE INFLAMMATORY RESPONSES, WHICH SEEM TO BE DRIVEN BY METABOLIC-DEPENDENT EPIGENETIC CHANGES. IN THIS REVIEW ARTICLE WE PROVIDE A BRIEF OVERVIEW OF MITOCHONDRIAL FUNCTIONS AND AGE-RELATED CHANGES THAT OCCUR TO MACROPHAGES, WITH AN EMPHASIS ON HOW THE INFLAMMAGING ENVIRONMENT, SENESCENCE, AND NAD DECLINE CAN AFFECT THEIR METABOLISM, PROMOTE DYSREGULATION, AND CONTRIBUTE TO INFLAMMAGING AND AGE-RELATED PATHOLOGIES. 2020 7 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 8 6502 24 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 9 1310 21 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 10 6452 22 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 11 6466 26 TISSUE STEM CELLS AND CANCER STEM CELLS: POTENTIAL IMPLICATIONS FOR GASTRIC CANCER. GASTRIC CANCER REMAINS THE SECOND LEADING CAUSE OF DEATH IN THE WORLD TODAY, MAKING THE SEARCH FOR ITS MOLECULAR AND CELLULAR BASIS AN IMPORTANT PRIORITY. THOUGH RECOGNITION OF THE TIGHT LINK BETWEEN INFLAMMATION AND TUMORIGENESIS IS CENTURIES OLD, ONLY RECENTLY ARE THE PIECES OF THE ETIOLOGICAL PUZZLE BEGINNING TO FALL TOGETHER. RECENT ADVANCES IN GASTRIC STEM CELL BIOLOGY APPEAR TO BE CENTRAL TO THIS SLOWLY RESOLVING PUZZLE. AT LEAST TWO TYPES OF STEM CELLS MAY BE IMPORTANT. RESIDENT ADULT OR TISSUE STEM CELLS MAY, IN A CHRONICALLY INFLAMED ENVIRONMENT, SLOWLY ACQUIRE A SERIES OF GENETIC AND EPIGENETIC CHANGES THAT LEAD TO THEIR EMERGENCE AS ''CANCER STEM CELLS''. THIS SCENARIO HAS NOT YET BEEN PROVEN EXPERIMENTALLY, ALTHOUGH THE FIRST STEP, PROSPECTIVE RECOGNITION OF A GASTRIC STEM CELL HAS RECENTLY BEEN CONQUERED. ALTERNATIVELY, THE SETTING OF CHRONIC INFLAMMATORY STRESS AND INJURY MAY LEAD TO LOSS OF THE INDIGENOUS GASTRIC STEM CELLS FROM THEIR NICHES; BONE MARROW DERIVED STEM CELLS MAY THEN BE RECRUITED TO AND ENGRAFT INTO THE GASTRIC EPITHELIUM. SUCH RECRUITED CELLS HAVE THE POTENTIAL TO CONTRIBUTE TO THE TUMOR MASS. INDEED, EVIDENCE SUPPORTING THIS SCENARIO HAS BEEN PUBLISHED. HERE, WE REVIEW THESE RECENT FINDINGS AND DISCUSS IMPLICATIONS FOR THE FUTURE. 2008 12 2861 31 FROM TRAINED IMMUNITY IN ALLERGY TO TRAINED IMMUNITY-BASED ALLERGEN VACCINES. INNATE IMMUNE CELLS EXPERIENCE LONG LASTING METABOLIC AND EPIGENETIC CHANGES AFTER AN ENCOUNTER WITH SPECIFIC STIMULI. THIS FACILITATES ENHANCED IMMUNE RESPONSES UPON SECONDARY EXPOSITION TO BOTH THE SAME AND UNRELATED PATHOGENS, A PROCESS TERMED TRAINED IMMUNITY. TRAINED IMMUNITY-BASED VACCINES (TIBV) ARE VACCINES ABLE TO INDUCE INNATE IMMUNE MEMORY, THUS CONFERRING HETEROLOGOUS PROTECTION AGAINST A BROAD RANGE OF PATHOGENS. WHILE TRAINED IMMUNITY HAS BEEN WELL DOCUMENTED IN THE CONTEXT OF INFECTIONS AND MULTIPLE IMMUNE-MEDIATED DISEASES, THE ROLE OF INNATE IMMUNE MEMORY AND ITS CONTRIBUTION TO THE INITIATION AND MAINTENANCE OF CHRONIC ALLERGIC DISEASES REMAINS POORLY UNDERSTOOD. OVER THE LAST YEARS, DIFFERENT STUDIES ATTEMPTING TO UNCOVER THE ROLE OF TRAINED IMMUNITY IN ALLERGY HAVE EMERGED. EXPOSITION TO ENVIRONMENTAL FACTORS IMPACTING ALLERGY DEVELOPMENT SUCH AS ALLERGENS OR VIRUSES INDUCES THE REPROGRAMMING OF INNATE IMMUNE CELLS TO ACQUIRE A MORE PRO-INFLAMMATORY PHENOTYPE IN THE CONTEXT OF ASTHMA OR FOOD ALLERGY. SEVERAL STUDIES HAVE CONVINCINGLY DEMONSTRATED THAT PREVENTION OF VIRAL INFECTIONS USING TIBV CONTRIBUTES TO REDUCE WHEEZING ATTACKS IN CHILDREN, WHICH REPRESENT A HIGH-RISK FACTOR FOR ASTHMA DEVELOPMENT LATER IN LIFE. INNATE IMMUNE CELLS TRAINED WITH SPECIFIC STIMULI MIGHT ALSO ACQUIRE ANTI-INFLAMMATORY FEATURES AND PROMOTE TOLERANCE, WHICH MAY HAVE IMPORTANT IMPLICATIONS FOR CHRONIC INFLAMMATORY DISEASES SUCH AS ALLERGIES. RECENT FINDINGS SHOWED THAT ALLERGOID-MANNAN CONJUGATES, WHICH ARE NEXT GENERATION VACCINES FOR ALLERGEN-SPECIFIC IMMUNOTHERAPY (AIT), ARE ABLE TO REPROGRAM MONOCYTES INTO TOLEROGENIC DENDRITIC CELLS BY MECHANISMS DEPENDING ON METABOLIC AND EPIGENETIC REWIRING. A BETTER UNDERSTANDING OF THE UNDERLYING MECHANISMS OF TRAINED IMMUNITY IN ALLERGY WILL PAVE THE WAY FOR THE DESIGN OF NOVEL TRAINED IMMUNITY-BASED ALLERGEN VACCINES AS POTENTIAL ALTERNATIVE STRATEGIES FOR THE PREVENTION AND TREATMENT OF ALLERGIC DISEASES. 2023 13 6506 18 TRAINED INNATE IMMUNITY NOT ALWAYS AMICABLE. THE CONCEPT OF „TRAINED INNATE IMMUNITY" IS UNDERSTOOD AS THE ABILITY OF INNATE IMMUNE CELLS TO REMEMBER INVADING AGENTS AND TO RESPOND NONSPECIFICALLY TO REINFECTION WITH INCREASED STRENGTH. TRAINED IMMUNITY IS ORCHESTRATED BY EPIGENETIC MODIFICATIONS LEADING TO CHANGES IN GENE EXPRESSION AND CELL PHYSIOLOGY. ALTHOUGH THIS PHENOMENON WAS ORIGINALLY SEEN MAINLY AS A BENEFICIAL EFFECT, SINCE IT CONFERS BROAD IMMUNOLOGICAL PROTECTION, ENHANCED IMMUNE RESPONSE OF REPROGRAMMED INNATE IMMUNE CELLS MIGHT RESULT IN THE DEVELOPMENT OR PERSISTENCE OF CHRONIC METABOLIC, AUTOIMMUNE OR NEUROINFALMMATORY DISORDERS. THIS PAPER OVERVIEWS SEVERAL EXAMPLES WHERE THE INDUCTION OF TRAINED IMMUNITY MAY BE ESSENTIAL IN THE DEVELOPMENT OF DISEASES CHARACTERIZED BY FLAWED INNATE IMMUNE RESPONSE. 2019 14 3544 21 IMMUNOMETABOLIC CONTROL OF TRAINED IMMUNITY. INNATE IMMUNE CELLS CAN ADOPT LONG-TERM INFLAMMATORY PHENOTYPES FOLLOWING BRIEF ENCOUNTERS WITH EXOGENOUS (MICROBIAL) OR ENDOGENOUS STIMULI. THIS PHENOMENON IS NAMED TRAINED IMMUNITY AND CAN IMPROVE HOST DEFENSE AGAINST (RECURRENT) INFECTIONS. IN CONTRAST, TRAINED IMMUNITY CAN ALSO BE MALADAPTIVE IN THE CONTEXT OF CHRONIC INFLAMMATORY DISORDERS, SUCH AS ATHEROSCLEROSIS. KEY TO FUTURE THERAPEUTIC EXPLOITATION OF THIS MECHANISM IS THOROUGH KNOWLEDGE OF THE MECHANISMS DRIVING TRAINED IMMUNITY, WHICH CAN BE USED AS PHARMACOLOGICAL TARGETS. THESE MECHANISMS INCLUDE PROFOUND CHANGES IN INTRACELLULAR METABOLISM, WHICH ARE CLOSELY INTERTWINED WITH EPIGENETIC REPROGRAMMING AT THE LEVEL OF HISTONE MODIFICATIONS. GLYCOLYSIS, GLUTAMINE REPLENISHMENT OF THE TRICARBOXYLIC ACID CYCLE WITH ACCUMULATION OF FUMARATE, AND THE MEVALONATE PATHWAY HAVE ALL BEEN IDENTIFIED AS CRITICAL PATHWAYS FOR TRAINED IMMUNITY IN MONOCYTES AND MACROPHAGES. IN THIS REVIEW, WE PROVIDE A STATE-OF-THE-ART OVERVIEW OF HOW THESE METABOLIC PATHWAYS INTERACT WITH EPIGENETIC PROGRAMS TO DEVELOP TRAINED IMMUNITY. 2021 15 6494 23 TRAINED IMMUNITY AS A NOVEL THERAPEUTIC STRATEGY. RECENT STUDIES HAVE SHOWN THAT UPON CERTAIN VACCINATIONS OR INFECTIONS HUMAN INNATE IMMUNE CELLS CAN UNDERGO EXTENSIVE METABOLIC AND EPIGENETIC REPROGRAMMING, WHICH RESULTS IN ENHANCED IMMUNE RESPONSES UPON HETEROLOGOUS RE-INFECTION, A PROCESS TERMED TRAINED IMMUNITY. TRAINED IMMUNITY HAS ALSO BEEN SHOWN TO BE INAPPROPRIATELY ACTIVATED IN INFLAMMATORY DISEASES. THIS PROVIDES THE POTENTIAL FOR IDENTIFYING NOVEL THERAPEUTIC TARGETS: POTENTIATION OF TRAINED IMMUNITY COULD PROTECT FROM SECONDARY INFECTIONS AND REVERSE IMMUNOTOLERANT STATES, WHILE INHIBITION OF TRAINED IMMUNITY MIGHT REDUCE EXCESSIVE IMMUNE ACTIVATION IN CHRONIC INFLAMMATORY CONDITIONS. BY TARGETING SPECIFIC MECHANISMS OF TRAINED IMMUNITY ON EITHER IMMUNOLOGIC, METABOLIC OR EPIGENETIC LEVEL, NOVEL THERAPEUTIC APPROACHES COULD BE DEVELOPED. 2018 16 3769 18 INTEGRATIVE MEDICINE TO TACKLE THE PROBLEM OF CHRONIC DISEASES. THIS ARTICLE SUMMARIZES IMPORTANT WAYS THAT INTEGRATIVE MEDICINE CAN CONTRIBUTE TO RESOLVING THE GLOBAL HEALTH CRISIS WITH SPECIAL REFERENCE TO THE US. RESEARCH USING MODERN METHODS OF ANALYSIS OF CELLULAR CHANGES AT THE EPIGENETIC LEVEL HAS SHOWN THAT DIET AND LIFESTYLE INTERVENTIONS GREATLY IMPROVE THE STATE OF PATIENTS' HEALTH. ESTIMATES HAVE BEEN GIVEN THAT UP TO 75% OF ALL US HEALTH COSTS CAN BE SAVED BY THESE METHODS, PARTICULARLY IF APPLIED PREVENTATIVELY. IT IS THUS VITAL THAT ACTIVE STEPS ARE TAKEN TO IMPLEMENT SUCH PROGRAMS, TO REDUCE COSTS TO CITIZENS AND SOCIETY ALIKE, AS WELL AS TO GOVERNMENT. 2010 17 6430 26 THE USE OF MEDICAL OZONE IN CHRONIC INTERVERTEBRAL DISC DEGENERATION CAN BE AN ETIOLOGICAL AND CONSERVATIVE TREATMENT. DEGENERATION OF THE INTERVERTEBRAL DISC IS ONE OF THE MOST FREQUENT CAUSES OF LUMBAR PAIN, AND IT PUTS AN EXTREME STRAIN ON WORLDWIDE HEALTHCARE SYSTEMS. FINDING A SOLUTION FOR THIS DISEASE IS AN IMPORTANT CHALLENGE AS CURRENT SURGICAL AND CONSERVATIVE TREATMENTS FAIL TO BRING A SHORT-TERM OR LONG-TERM SOLUTION TO THE PROBLEM. MEDICAL OZONE HAS YIELDED EXCELLENT RESULTS IN INTERVERTEBRAL DISC PATHOLOGY. WHEN IT COMES TO EXTRUDED DISC HERNIATION, OZONE IS THE ONLY ETIOLOGICAL TREATMENT BECAUSE IT STIMULATES THE IMMUNE SYSTEM TO ABSORB THE HERNIATED PORTION OF THE NUCLEUS PULPOSUS, THUS RESOLVING DISCAL EXTRUSION. THIS WORK AIMS TO EXAMINE THE BIOMOLECULAR MECHANISMS THAT LEAD TO INTERVERTEBRAL DISC DEGENERATION WHILE HIGHLIGHTING THE SIGNIFICANCE OF OXIDATIVE STRESS AND CHRONIC INFLAMMATION. CONSIDERING THAT OZONE IS A REGULATOR OF OXIDATIVE STRESS AND, THEREFORE, OF INFLAMMATION, WE ASSERT THAT MEDICAL OZONE COULD MODULATE THIS PROCESS AND OBTAIN INFLAMMATORY STAGE MACROPHAGES (M1) TO SWITCH TO THE REPAIR PHASE (M2). CONSEQUENTLY, THE OZONE WOULD BE A THERAPEUTIC RESOURCE THAT WOULD WORK ON THE ETIOLOGY OF THE DISEASE AS AN EPIGENETIC REGULATOR THAT WOULD HELP REPAIR THE INTERVERTEBRAL SPACE. 2023 18 6376 22 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 19 3700 21 INFLAMMATORY MEMORY AND TISSUE ADAPTATION IN SICKNESS AND IN HEALTH. OUR BODY HAS A REMARKABLE ABILITY TO REMEMBER ITS PAST ENCOUNTERS WITH ALLERGENS, PATHOGENS, WOUNDS AND IRRITANTS, AND TO REACT MORE QUICKLY TO THE NEXT EXPERIENCE. THIS ACCENTUATED SENSITIVITY ALSO HELPS US TO COPE WITH NEW THREATS. DESPITE MAINTAINING A STATE OF READINESS AND BROADENED RESISTANCE TO SUBSEQUENT PATHOGENS, MEMORIES CAN ALSO BE MALADAPTIVE, LEADING TO CHRONIC INFLAMMATORY DISORDERS AND CANCERS. WITH THE EVER-INCREASING EMERGENCE OF NEW PATHOGENS, ALLERGENS AND POLLUTANTS IN OUR WORLD, THE URGENCY TO UNRAVEL THE MOLECULAR UNDERPINNINGS OF THESE PHENOMENA HAS RISEN TO NEW HEIGHTS. HERE WE REFLECT ON HOW THE FIELD OF INFLAMMATORY MEMORY HAS EVOLVED, SINCE 2007, WHEN RESEARCHERS REALIZED THAT NON-SPECIFIC MEMORY IS CONTAINED IN THE NUCLEUS AND PROPAGATED AT THE EPIGENETIC LEVEL. WE REVIEW THE FLURRY OF RECENT DISCOVERIES REVEALING THAT MEMORY IS NOT JUST A PRIVILEGE OF THE IMMUNE SYSTEM BUT ALSO EXTENDS TO EPITHELIA OF THE SKIN, LUNG, INTESTINE AND PANCREAS, AND TO NEURONS. ALTHOUGH STILL UNFOLDING, EPIGENETIC MEMORIES OF INFLAMMATION HAVE NOW BEEN LINKED TO POSSIBLE BRAIN DISORDERS SUCH AS ALZHEIMER DISEASE, AND TO AN ELEVATED RISK OF CANCER. IN THIS REVIEW, WE CONSIDER THE CONSEQUENCES-GOOD AND BAD-OF THESE EPIGENETIC MEMORIES AND THEIR IMPLICATIONS FOR HUMAN HEALTH AND DISEASE. 2022 20 5631 27 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