1 6214 140 THE INTRACELLULAR SIGNALING PATHWAYS GOVERNING MACROPHAGE ACTIVATION AND FUNCTION IN HUMAN ATHEROSCLEROSIS. ATHEROSCLEROSIS IS A CHRONIC INFLAMMATORY DISEASE CHARACTERIZED BY LIPID ACCUMULATION AND PLAQUE FORMATION IN ARTERIAL VESSEL WALLS. ATHEROSCLEROTIC PLAQUES NARROW THE ARTERIAL LUMEN TO INCREASE THE RISK OF HEART ATTACKS, ISCHEMIC STROKE AND PERIPHERAL VASCULAR DISEASE, WHICH ARE MAJOR AND WORLDWIDE HEALTH AND ECONOMIC BURDENS. MACROPHAGE ACCUMULATION WITHIN PLAQUES IS CHARACTERISTIC OF ALL STAGES OF ATHEROSCLEROSIS AND THEIR PRESENCE IS A POTENTIAL MARKER OF DISEASE ACTIVITY AND PLAQUE STABILITY. MACROPHAGES ENGULF LIPIDS AND MODIFIED LIPOPROTEINS TO FORM FOAM CELLS THAT EXPRESS PRO-INFLAMMATORY AND CHEMOTACTIC EFFECTOR MOLECULES, STRESS INDUCING FACTORS AND REACTIVE OXYGEN SPECIES. THEY CONTROL PLAQUE STABILITY AND RUPTURE THROUGH SECRETION OF METALLOPROTEINASES AND EXTRACELLULAR MATRIX DEGRADATION. ALTHOUGH MACROPHAGES CAN WORSEN DISEASE BY PROPAGATING INFLAMMATION, THEY CAN STABILIZE ATHEROSCLEROTIC PLAQUES THROUGH TISSUE REMODELING, PROMOTING THE FORMATION OF A FIBROUS CAP, CLEARING APOPTOTIC CELLS TO PREVENT NECROTIC CORE FORMATION AND THROUGH VASCULAR REPAIR. IN ATHEROSCLEROSIS, MACROPHAGES RESPOND TO DYSLIPIDAEMIA, CYTOKINES, DYING CELLS, METABOLIC FACTORS, LIPIDS, PHYSICAL STIMULI AND EPIGENETIC FACTORS AND EXHIBIT HETEROGENEITY IN THEIR ACTIVATION DEPENDING ON THE STIMULI THEY RECEIVE. UNDERSTANDING THESE SIGNALS AND THE PATHWAYS DRIVING MACROPHAGE FUNCTION WITHIN DEVELOPING AND ESTABLISHED PLAQUES AND HOW THEY CAN BE PHARMACOLOGICALLY MODULATED, REPRESENTS A STRATEGY FOR THE PREVENTION AND TREATMENT OF ATHEROSCLEROSIS. THIS REVIEW FOCUSSES ON THE CURRENT UNDERSTANDING OF FACTORS CONTROLLING MACROPHAGE HETEROGENEITY AND FUNCTION IN ATHEROSCLEROSIS. PARTICULAR ATTENTION IS GIVEN TO THE MACROPHAGE INTRACELLULAR SIGNALING PATHWAYS AND TRANSCRIPTION FACTORS ACTIVATED BY BIOCHEMICAL AND BIOPHYSICAL STIMULI WITHIN PLAQUES, AND HOW THEY ARE INTEGRATED TO REGULATE PLAQUE FORMATION AND STABILITY. 2022 2 5933 39 TARGETING EPIGENETICS AND NON-CODING RNAS IN ATHEROSCLEROSIS: FROM MECHANISMS TO THERAPEUTICS. ATHEROSCLEROSIS, THE PRINCIPAL CAUSE OF CARDIOVASCULAR DEATH WORLDWIDE, IS A PATHOLOGICAL DISEASE CHARACTERIZED BY FIBRO-PROLIFERATION, CHRONIC INFLAMMATION, LIPID ACCUMULATION, AND IMMUNE DISORDER IN THE VESSEL WALL. AS THE ATHEROMATOUS PLAQUES DEVELOP INTO ADVANCED STAGE, THE VULNERABLE PLAQUES ARE PRONE TO RUPTURE, WHICH CAUSES ACUTE CARDIOVASCULAR EVENTS, INCLUDING ISCHEMIC STROKE AND MYOCARDIAL INFARCTION. EMERGING EVIDENCE HAS SUGGESTED THAT ATHEROSCLEROSIS IS ALSO AN EPIGENETIC DISEASE WITH THE INTERPLAY OF MULTIPLE EPIGENETIC MECHANISMS. THE EPIGENETIC BASIS OF ATHEROSCLEROSIS HAS TRANSFORMED OUR KNOWLEDGE OF EPIGENETICS FROM AN IMPORTANT BIOLOGICAL PHENOMENON TO A BURGEONING FIELD IN CARDIOVASCULAR RESEARCH. HERE, WE PROVIDE A SYSTEMATIC AND UP-TO-DATE OVERVIEW OF THE CURRENT KNOWLEDGE OF THREE DISTINCT BUT INTERRELATED EPIGENETIC PROCESSES (INCLUDING DNA METHYLATION, HISTONE METHYLATION/ACETYLATION, AND NON-CODING RNAS), IN ATHEROSCLEROTIC PLAQUE DEVELOPMENT AND INSTABILITY. MECHANISTIC AND CONCEPTUAL ADVANCES IN UNDERSTANDING THE BIOLOGICAL ROLES OF VARIOUS EPIGENETIC MODIFIERS IN REGULATING GENE EXPRESSION AND FUNCTIONS OF ENDOTHELIAL CELLS (VASCULAR HOMEOSTASIS, LEUKOCYTE ADHESION, ENDOTHELIAL-MESENCHYMAL TRANSITION, ANGIOGENESIS, AND MECHANOTRANSDUCTION), SMOOTH MUSCLE CELLS (PROLIFERATION, MIGRATION, INFLAMMATION, HYPERTROPHY, AND PHENOTYPIC SWITCH), AND MACROPHAGES (DIFFERENTIATION, INFLAMMATION, FOAM CELL FORMATION, AND POLARIZATION) ARE DISCUSSED. THE INHERENTLY DYNAMIC NATURE AND REVERSIBILITY OF EPIGENETIC REGULATION, ENABLES THE POSSIBILITY OF EPIGENETIC THERAPY BY TARGETING EPIGENETIC "WRITERS", "READERS", AND "ERASERS". SEVERAL FOOD DRUG ADMINISTRATION-APPROVED SMALL-MOLECULE EPIGENETIC DRUGS SHOW PROMISE IN PRE-CLINICAL STUDIES FOR THE TREATMENT OF ATHEROSCLEROSIS. FINALLY, WE DISCUSS POTENTIAL THERAPEUTIC IMPLICATIONS AND CHALLENGES FOR FUTURE RESEARCH INVOLVING CARDIOVASCULAR EPIGENETICS, WITH AN AIM TO PROVIDE A TRANSLATIONAL PERSPECTIVE FOR IDENTIFYING NOVEL BIOMARKERS OF ATHEROSCLEROSIS, AND TRANSFORMING PRECISION CARDIOVASCULAR RESEARCH AND DISEASE THERAPY IN MODERN ERA OF EPIGENETICS. 2019 3 4489 32 MONOCYTE AND MACROPHAGE IMMUNOMETABOLISM IN ATHEROSCLEROSIS. ATHEROSCLEROSIS IS CHARACTERIZED BY CHRONIC LOW GRADE INFLAMMATION OF ARTERIES THAT RESULTS IN THE DEVELOPMENT OF LIPID DENSE PLAQUES. CHRONIC INFLAMMATION INDUCED BY WESTERN-TYPE DIET IS ASSOCIATED WITH THE RISK OF DEVELOPING ATHEROSCLEROSIS, AND NEW INSIGHTS SHED LIGHT ON THE IMPORTANCE OF METABOLIC AND FUNCTIONAL REPROGRAMMING IN MONOCYTES AND MACROPHAGES FOR PROGRESSION OF ATHEROSCLEROSIS. THIS REVIEW AIMS TO PROVIDE AN OVERVIEW OF OUR CURRENT UNDERSTANDING INTO HOW THE METABOLIC REPROGRAMMING OF GLUCOSE, CHOLESTEROL, FATTY ACID, AND AMINO ACID METABOLISM IN MACROPHAGES CONTRIBUTES TO INFLAMMATION DURING ATHEROSCLEROSIS. RECENT INSIGHTS SUGGEST THAT TRANSCRIPTIONAL AND EPIGENETIC ADAPTATION WITHIN INNATE IMMUNE CELLS (TERMED TRAINED IMMUNITY) PLAY AN IMPORTANT ROLE IN THE PATHOGENESIS OF ATHEROSCLEROSIS. WE PROPOSE THAT METABOLIC CHANGES INDUCED BY PRO-ATHEROGENIC LIPOPROTEINS PARTLY MEDIATE THESE CHANGES IN TRAINED MACROPHAGES. FINALLY, WE DISCUSS THE POSSIBILITY OF MANIPULATING CELLULAR METABOLISM OF IMMUNE CELLS FOR TARGETED THERAPEUTIC INTERVENTION AGAINST ATHEROSCLEROSIS. 2018 4 1712 44 DYSFUNCTIONAL VASCULAR ENDOTHELIUM AS A DRIVER OF ATHEROSCLEROSIS: EMERGING INSIGHTS INTO PATHOGENESIS AND TREATMENT. ATHEROSCLEROSIS, THE CHRONIC ACCUMULATION OF CHOLESTEROL-RICH PLAQUE WITHIN ARTERIES, IS ASSOCIATED WITH A BROAD SPECTRUM OF CARDIOVASCULAR DISEASES INCLUDING MYOCARDIAL INFARCTION, AORTIC ANEURYSM, PERIPHERAL VASCULAR DISEASE, AND STROKE. ATHEROSCLEROTIC CARDIOVASCULAR DISEASE REMAINS A LEADING CAUSE OF MORTALITY IN HIGH-INCOME COUNTRIES AND RECENT YEARS HAVE WITNESSED A NOTABLE INCREASE IN PREVALENCE WITHIN LOW- AND MIDDLE-INCOME REGIONS OF THE WORLD. CONSIDERING THIS PROMINENT AND EVOLVING GLOBAL BURDEN, THERE IS A NEED TO IDENTIFY THE CELLULAR MECHANISMS THAT UNDERLIE THE PATHOGENESIS OF ATHEROSCLEROSIS TO DISCOVER NOVEL THERAPEUTIC TARGETS FOR PREVENTING OR MITIGATING ITS CLINICAL SEQUELAE. DESPITE DECADES OF RESEARCH, WE STILL DO NOT FULLY UNDERSTAND THE COMPLEX CELL-CELL INTERACTIONS THAT DRIVE ATHEROSCLEROSIS, BUT NEW INVESTIGATIVE APPROACHES ARE RAPIDLY SHEDDING LIGHT ON THESE ESSENTIAL MECHANISMS. THE VASCULAR ENDOTHELIUM RESIDES AT THE INTERFACE OF SYSTEMIC CIRCULATION AND THE UNDERLYING VESSEL WALL AND PLAYS AN ESSENTIAL ROLE IN GOVERNING PATHOPHYSIOLOGICAL PROCESSES DURING ATHEROGENESIS. IN THIS REVIEW, WE PRESENT EMERGING EVIDENCE THAT IMPLICATES THE ACTIVATED ENDOTHELIUM AS A DRIVER OF ATHEROSCLEROSIS BY DIRECTING SITE-SPECIFICITY OF PLAQUE FORMATION AND BY PROMOTING PLAQUE DEVELOPMENT THROUGH INTRACELLULAR PROCESSES, WHICH REGULATE ENDOTHELIAL CELL PROLIFERATION AND TURNOVER, METABOLISM, PERMEABILITY, AND PLASTICITY. MOREOVER, WE HIGHLIGHT NOVEL MECHANISMS OF INTERCELLULAR COMMUNICATION BY WHICH ENDOTHELIAL CELLS MODULATE THE ACTIVITY OF KEY VASCULAR CELL POPULATIONS INVOLVED IN ATHEROGENESIS, AND DISCUSS HOW ENDOTHELIAL CELLS CONTRIBUTE TO RESOLUTION BIOLOGY - A PROCESS THAT IS DYSREGULATED IN ADVANCED PLAQUES. FINALLY, WE DESCRIBE IMPORTANT FUTURE DIRECTIONS FOR PRECLINICAL ATHEROSCLEROSIS RESEARCH, INCLUDING EPIGENETIC AND TARGETED THERAPIES, TO LIMIT THE PROGRESSION OF ATHEROSCLEROSIS IN AT-RISK OR AFFECTED PATIENTS. 2021 5 5423 32 REGULATION OF MACROPHAGE ACTIVATION AND DIFFERENTIATION IN ATHEROSCLEROSIS. CHRONIC INFLAMMATION IS A HALLMARK OF ATHEROSCLEROSIS AND MACROPHAGES PLAY A CENTRAL ROLE IN CONTROLLING INFLAMMATION AT ALL STAGES OF ATHEROSCLEROSIS. IN ATHEROSCLEROSIS, MACROPHAGES AND MONOCYTE-DERIVED MACROPHAGES ARE CONTINUOUSLY EXPOSED TO CHOLESTEROL, OXIDIZED LIPIDS, CELL DEBRIS, CYTOKINES, AND CHEMOKINES. NOT ONLY DO THESE STIMULI INDUCE A SPECIFIC MACROPHAGE PHENOTYPE, BUT THEY ALSO INTERACT EXTENSIVELY, LEADING TO MACROPHAGE HETEROGENEITY IN ATHEROSCLEROTIC PLAQUES. HEREIN, WE REVIEW THE DIVERSE PHENOTYPES OF MACROPHAGES, THE MECHANISMS UNDERLYING MACROPHAGE ACTIVATION, AND THE CONTRIBUTIONS OF MACROPHAGES TO ATHEROSCLEROSIS IN THIS CONTEXT. WE ALSO SUMMARIZE RECENT STUDIES ON FOAMY MACROPHAGES AND MONOCYTE-DERIVED MACROPHAGES IN PLAQUE DURING DISEASE PROGRESSION. WE PROVIDE A COMPREHENSIVE OVERVIEW OF TRANSCRIPTIONAL, EPIGENETIC, AND METABOLIC REPROGRAMMING OF MACROPHAGES AND DISCUSS THE EMERGING CONCEPTS OF TARGETING CYTOKINES AND MACROPHAGES TO MODULATE ATHEROSCLEROSIS. 2021 6 2343 31 EPIGENETIC REGULATION OF MACROPHAGE POLARIZATION IN CARDIOVASCULAR DISEASES. CARDIOVASCULAR DISEASES (CVDS) ARE THE LEADING CAUSE OF HOSPITALIZATION AND DEATH WORLDWIDE, ESPECIALLY IN DEVELOPING COUNTRIES. THE INCREASED PREVALENCE RATE AND MORTALITY DUE TO CVDS, DESPITE THE DEVELOPMENT OF SEVERAL APPROACHES FOR PREVENTION AND TREATMENT, ARE ALARMING TRENDS IN GLOBAL HEALTH. CHRONIC INFLAMMATION AND MACROPHAGE INFILTRATION ARE KEY REGULATORS OF THE INITIATION AND PROGRESSION OF CVDS. RECENT DATA SUGGEST THAT EPIGENETIC MODIFICATIONS, SUCH AS DNA METHYLATION, POSTTRANSLATIONAL HISTONE MODIFICATIONS, AND RNA MODIFICATIONS, REGULATE CELL DEVELOPMENT, DNA DAMAGE REPAIR, APOPTOSIS, IMMUNITY, CALCIUM SIGNALING, AND AGING IN CARDIOMYOCYTES; AND ARE INVOLVED IN MACROPHAGE POLARIZATION AND CONTRIBUTE SIGNIFICANTLY TO CARDIAC DISEASE DEVELOPMENT. CARDIAC MACROPHAGES NOT ONLY TRIGGER DAMAGING INFLAMMATORY RESPONSES DURING ATHEROSCLEROTIC PLAQUE FORMATION, MYOCARDIAL INJURY, AND HEART FAILURE BUT ARE ALSO INVOLVED IN TISSUE REPAIR, REMODELING, AND REGENERATION. IN THIS REVIEW, WE SUMMARIZE THE KEY EPIGENETIC MODIFICATIONS THAT INFLUENCE MACROPHAGE POLARIZATION AND CONTRIBUTE TO THE PATHOPHYSIOLOGY OF CVDS, AND HIGHLIGHT THEIR POTENTIAL FOR THE DEVELOPMENT OF ADVANCED EPIGENETIC THERAPIES. 2023 7 4488 32 MONOCYTE AND HAEMATOPOIETIC PROGENITOR REPROGRAMMING AS COMMON MECHANISM UNDERLYING CHRONIC INFLAMMATORY AND CARDIOVASCULAR DISEASES. A LARGE NUMBER OF CARDIOVASCULAR EVENTS ARE NOT PREVENTED BY CURRENT THERAPEUTIC REGIMENS. IN SEARCH FOR ADDITIONAL, INNOVATIVE STRATEGIES, IMMUNE CELLS HAVE BEEN RECOGNIZED AS KEY PLAYERS CONTRIBUTING TO ATHEROSCLEROTIC PLAQUE PROGRESSION AND DESTABILIZATION. PARTICULARLY THE ROLE OF INNATE IMMUNE CELLS IS OF MAJOR INTEREST, FOLLOWING THE RECENT PARADIGM SHIFT THAT INNATE IMMUNITY, LONG CONSIDERED TO BE INCAPABLE OF LEARNING, DOES EXHIBIT IMMUNOLOGICAL MEMORY MEDIATED VIA EPIGENETIC REPROGRAMMING. COMPELLING EVIDENCE SHOWS THAT ATHEROSCLEROTIC RISK FACTORS PROMOTE IMMUNE CELL MIGRATION BY PRE-ACTIVATION OF CIRCULATING INNATE IMMUNE CELLS. INNATE IMMUNE CELL ACTIVATION VIA METABOLIC AND EPIGENETIC REPROGRAMMING PERPETUATES A SYSTEMIC LOW-GRADE INFLAMMATORY STATE IN CARDIOVASCULAR DISEASE (CVD) THAT IS ALSO COMMON IN OTHER CHRONIC INFLAMMATORY DISORDERS. THIS OPENS A NEW THERAPEUTIC AREA IN WHICH METABOLIC OR EPIGENETIC MODULATION OF INNATE IMMUNE CELLS MAY RESULT IN DECREASED SYSTEMIC CHRONIC INFLAMMATION, ALLEVIATING CVD, AND ITS CO-MORBIDITIES. 2018 8 2291 26 EPIGENETIC REGULATION IN PATHOLOGY OF ATHEROSCLEROSIS: A NOVEL PERSPECTIVE. ATHEROSCLEROSIS, CHARACTERIZED BY ATHEROSCLEROTIC PLAQUES, IS A COMPLEX PATHOLOGICAL PROCESS THAT INVOLVES DIFFERENT CELL TYPES AND CAN BE SEEN AS A CHRONIC INFLAMMATORY DISEASE. IN THE ADVANCED STAGE, THE RUPTURED ATHEROSCLEROTIC PLAQUE CAN INDUCE DEADLY ACCIDENTS INCLUDING ISCHEMIC STROKE AND MYOCARDIAL INFARCTION. EPIGENETICS REGULATION, INCLUDING DNA METHYLATION, HISTONE MODIFICATION, AND NON-CODING RNA MODIFICATION. MAINTAINS CELLULAR IDENTITY VIA AFFECTING THE CELLULAR TRANSCRIPTOME. THE EPIGENETIC MODIFICATION PROCESS, MEDIATING BY EPIGENETIC ENZYMES, IS DYNAMIC UNDER VARIOUS STIMULI, WHICH CAN BE REVERSELY ALTERED. RECENTLY, NUMEROUS STUDIES HAVE EVIDENCED THE CLOSE RELATIONSHIP BETWEEN ATHEROSCLEROSIS AND EPIGENETIC REGULATIONS IN ATHEROSCLEROSIS, PROVIDING US WITH A NOVEL PERSPECTIVE IN RESEARCHING MECHANISMS AND FINDING NOVEL THERAPEUTIC TARGETS OF THIS SERIOUS DISEASE. HERE, WE CRITICALLY REVIEW THE RECENT DISCOVERIES BETWEEN EPIGENETIC REGULATION MECHANISMS IN ATHEROSCLEROSIS. 2021 9 3734 38 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 10 2168 25 EPIGENETIC MECHANISMS IN MONOCYTES/MACROPHAGES REGULATE INFLAMMATION IN CARDIOMETABOLIC AND VASCULAR DISEASE. CARDIOMETABOLIC AND VASCULAR DISEASE, WITH THEIR ASSOCIATED SECONDARY COMPLICATIONS, ARE THE LEADING CAUSE OF MORBIDITY AND MORTALITY IN WESTERN SOCIETY. CHRONIC INFLAMMATION IS A COMMON THEME THAT UNDERLIES INITIATION AND PROGRESSION OF CARDIOVASCULAR DISEASE. IN THIS REGARD, MONOCYTES/MACROPHAGES ARE KEY PLAYERS IN THE DEVELOPMENT OF A CHRONIC INFLAMMATORY STATE. OVER THE PAST DECADE, EPIGENETIC MODIFICATIONS, SUCH AS DNA METHYLATION AND POSTTRANSLATIONAL HISTONE PROCESSING, HAVE EMERGED AS IMPORTANT REGULATORS OF IMMUNE CELL PHENOTYPES. ACCUMULATING STUDIES REVEAL THE IMPORTANCE OF EPIGENETIC ENZYMES IN THE DYNAMIC REGULATION OF KEY SIGNALING PATHWAYS THAT ALTER MONOCYTE/MACROPHAGE PHENOTYPES IN RESPONSE TO ENVIRONMENTAL STIMULI. IN THIS REVIEW, WE HIGHLIGHT THE CURRENT PARADIGMS OF MONOCYTE/MACROPHAGE POLARIZATION AND THE EMERGING ROLE OF EPIGENETIC MODIFICATION IN THE REGULATION OF MONOCYTE/MACROPHAGE PHENOTYPE IN OBESITY, DIABETES MELLITUS, ATHEROSCLEROSIS, AND ABDOMINAL AORTIC ANEURYSMS. 2019 11 3776 35 INTERACTIONS BETWEEN DYSLIPIDEMIA AND THE IMMUNE SYSTEM AND THEIR RELEVANCE AS PUTATIVE THERAPEUTIC TARGETS IN ATHEROSCLEROSIS. CARDIOVASCULAR DISEASE (CVD) CONTINUES TO BE A LEADING CAUSE OF DEATH WORLDWIDE WITH ATHEROSCLEROSIS BEING THE MAJOR UNDERLYING PATHOLOGY. THE INTERPLAY BETWEEN LIPIDS AND IMMUNE CELLS IS BELIEVED TO BE A DRIVING FORCE IN THE CHRONIC INFLAMMATION OF THE ARTERIAL WALL DURING ATHEROGENESIS. ATHEROSCLEROSIS IS INITIATED AS LIPID PARTICLES ACCUMULATE AND BECOME TRAPPED IN VESSEL WALLS. THE SUBSEQUENT IMMUNE RESPONSE, INVOLVING BOTH ADAPTIVE AND IMMUNE CELLS, PROGRESSES PLAQUE DEVELOPMENT, WHICH MAY BE EXACERBATED UNDER DYSLIPIDEMIC CONDITIONS. BROAD EVIDENCE, ESPECIALLY FROM ANIMAL MODELS, CLEARLY DEMONSTRATES THE EFFECT OF LIPIDS ON IMMUNE CELLS FROM THEIR DEVELOPMENT IN THE BONE MARROW TO THEIR PHENOTYPIC SWITCHING IN CIRCULATION. INTERESTINGLY, RECENT RESEARCH HAS ALSO SHOWN A LONG-LASTING EPIGENETIC SIGNATURE FROM LIPIDS ON IMMUNE CELLS. TRADITIONALLY, CARDIOVASCULAR THERAPIES HAVE APPROACHED ATHEROSCLEROSIS THROUGH LIPID-LOWERING MEDICATIONS BECAUSE, UNTIL RECENTLY, ANTI-INFLAMMATORY THERAPIES HAVE BEEN LARGELY UNSUCCESSFUL IN CLINICAL TRIALS. HOWEVER, THE RECENT CANAKINUMAB ANTIINFLAMMATORY THROMBOSIS OUTCOMES STUDY (CANTOS) PROVIDED PIVOTAL SUPPORT OF THE INFLAMMATORY HYPOTHESIS OF ATHEROSCLEROSIS IN MAN SPURRING ON ANTI-INFLAMMATORY STRATEGIES TO TREAT ATHEROSCLEROSIS. IN THIS REVIEW, WE DESCRIBE THE INTERACTIONS BETWEEN LIPIDS AND IMMUNE CELLS ALONG WITH THEIR SPECIFIC OUTCOMES AS WELL AS DISCUSS THEIR FUTURE PERSPECTIVE AS POTENTIAL CARDIOVASCULAR TARGETS. 2019 12 6498 32 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 13 2532 28 EPIGENETICS IN ATHEROSCLEROSIS AND INFLAMMATION. ATHEROSCLEROSIS IS A MULTIFACTORIAL DISEASE WITH A SEVERE BURDEN ON WESTERN SOCIETY. RECENT INSIGHTS INTO THE PATHOGENESIS OF ATHEROSCLEROSIS UNDERSCORE THE IMPORTANCE OF CHRONIC INFLAMMATION IN BOTH THE INITIATION AND PROGRESSION OF VASCULAR REMODELLING. EXPRESSION OF IMMUNOREGULATORY MOLECULES BY VASCULAR WALL COMPONENTS WITHIN THE ATHEROSCLEROTIC LESIONS IS ACCORDINGLY THOUGHT TO CONTRIBUTE TO THE ONGOING INFLAMMATORY PROCESS. BESIDES GENE REGULATORY PROTEINS (TRANSCRIPTION FACTORS), EPIGENETIC MECHANISMS ALSO PLAY AN ESSENTIAL AND FUNDAMENTAL ROLE IN THE TRANSCRIPTIONAL CONTROL OF GENE EXPRESSION. THESE EPIGENETIC MECHANISMS CHANGE THE ACCESSIBILITY OF CHROMATIN BY DNA METHYLATION AND HISTONE MODIFICATIONS. EPIGENETIC MODULATORS ARE THUS CRITICALLY INVOLVED IN THE REGULATION OF VASCULAR, IMMUNE AND TISSUE-SPECIFIC GENE EXPRESSION WITHIN THE ATHEROSCLEROTIC LESION. IMPORTANTLY, EPIGENETIC PROCESSES ARE REVERSIBLE AND MAY PROVIDE AN EXCELLENT THERAPEUTIC TARGET. THE CONCEPT OF EPIGENETIC REGULATION IS GRADUALLY BEING RECOGNIZED AS AN IMPORTANT FACTOR IN THE PATHOGENESIS OF ATHEROSCLEROSIS. RECENT RESEARCH PROVIDES AN ESSENTIAL LINK BETWEEN INFLAMMATION AND REPROGRAMMING OF THE EPIGENOME. IN THIS REVIEW WE THEREFORE DISCUSS THE BASIS OF EPIGENETIC REGULATION - AND THE CONTRIBUTION THEREOF IN THE REGULATION OF INFLAMMATORY PROCESSES IN GENERAL AND DURING ATHEROSCLEROSIS IN PARTICULAR. MOREOVER WE HIGHLIGHT POTENTIAL THERAPEUTIC INTERVENTIONS BASED ON EPIGENETIC MECHANISMS. 2010 14 5931 35 TARGETING EPIGENETIC MODIFIERS TO REPROGRAMME MACROPHAGES IN NON-RESOLVING INFLAMMATION-DRIVEN ATHEROSCLEROSIS. EPIGENOMIC AND EPIGENETIC RESEARCH HAS BEEN PROVIDING SEVERAL NEW INSIGHTS INTO A VARIETY OF DISEASES CAUSED BY NON-RESOLVING INFLAMMATION, INCLUDING CARDIOVASCULAR DISEASES. ATHEROSCLEROSIS (AS) HAS LONG BEEN RECOGNIZED AS A CHRONIC INFLAMMATORY DISEASE OF THE ARTERIAL WALLS, CHARACTERIZED BY LOCAL PERSISTENT AND STEPWISE ACCELERATING INFLAMMATION WITHOUT RESOLUTION, ALSO KNOWN AS UNCONTROLLED INFLAMMATION. THE PATHOGENESIS OF AS IS DRIVEN PRIMARILY BY HIGHLY PLASTIC MACROPHAGES VIA THEIR POLARIZATION TO PRO- OR ANTI-INFLAMMATORY PHENOTYPES AS WELL AS OTHER NOVEL SUBTYPES RECENTLY IDENTIFIED BY SINGLE-CELL SEQUENCING. ALTHOUGH EMERGING EVIDENCE HAS INDICATED THE KEY ROLE OF THE EPIGENETIC MACHINERY IN THE REGULATION OF MACROPHAGE PLASTICITY, THE INVESTIGATION OF EPIGENETIC ALTERATIONS AND MODIFIERS IN AS AND RELATED INFLAMMATION IS STILL IN ITS INFANCY. AN INCREASING NUMBER OF THE EPIGENETIC MODIFIERS (E.G. TET2, DNMT3A, HDAC3, HDAC9, JMJD3, KDM4A) HAVE BEEN IDENTIFIED IN EPIGENETIC REMODELLING OF MACROPHAGES THROUGH DNA METHYLATION OR HISTONE MODIFICATIONS (E.G. METHYLATION, ACETYLATION, AND RECENTLY LACTYLATION) IN INFLAMMATION. THESE OR MANY UNEXPLORED MODIFIERS FUNCTION TO DETERMINE OR SWITCH THE DIRECTION OF MACROPHAGE POLARIZATION VIA TRANSCRIPTIONAL REPROGRAMMING OF GENE EXPRESSION AND INTRACELLULAR METABOLIC REWIRING UPON MICROENVIRONMENTAL CUES, THEREBY REPRESENTING A PROMISING TARGET FOR ANTI-INFLAMMATORY THERAPY IN AS. HERE, WE REVIEW UP-TO-DATE FINDINGS INVOLVING THE EPIGENETIC REGULATION OF MACROPHAGES TO SHED LIGHT ON THE MECHANISM OF UNCONTROLLED INFLAMMATION DURING AS ONSET AND PROGRESSION. WE ALSO DISCUSS CURRENT CHALLENGES FOR DEVELOPING AN EFFECTIVE AND SAFE ANTI-AS THERAPY THAT TARGETS THE EPIGENETIC MODIFIERS AND PROPOSE A POTENTIAL ANTI-INFLAMMATORY STRATEGY THAT REPOLARIZES MACROPHAGES FROM PRO- TO ANTI-INFLAMMATORY PHENOTYPES. 2021 15 4377 28 MITOCHONDRIAL AGING: FOCUS ON MITOCHONDRIAL DNA DAMAGE IN ATHEROSCLEROSIS - A MINI-REVIEW. ATHEROSCLEROSIS IS A COMPLEX DISEASE WHICH CAN BE DESCRIBED AS AN EXCESSIVE FIBROFATTY, PROLIFERATIVE, INFLAMMATORY RESPONSE TO DAMAGE TO THE ARTERY WALL INVOLVING SEVERAL CELL TYPES SUCH AS SMOOTH MUSCLE CELLS, MONOCYTE-DERIVED MACROPHAGES, LYMPHOCYTES, DENDRITIC CELLS AND PLATELETS. ON THE OTHER HAND, ATHEROSCLEROSIS IS A TYPICAL AGE-RELATED DEGENERATIVE PATHOLOGY, WHICH IS CHARACTERIZED BY SIGNS OF CELL SENESCENCE IN THE ARTERIAL WALL INCLUDING REDUCED CELL PROLIFERATION, IRREVERSIBLE GROWTH ARREST AND APOPTOSIS, INCREASED DNA DAMAGE, THE PRESENCE OF EPIGENETIC MODIFICATIONS, SHORTENING OF TELOMERE LENGTH AND MITOCHONDRIAL DYSFUNCTION. THE MOST PROMINENT CHARACTERISTICS OF MITOCHONDRIAL AGING ARE THEIR STRUCTURAL ALTERATIONS AND MITOCHONDRIAL DNA DAMAGE. THE MECHANISMS OF MITOCHONDRIAL GENOME DAMAGE IN THE DEVELOPMENT OF CHRONIC AGE-RELATED DISEASES SUCH AS ATHEROSCLEROSIS ARE NOT YET WELL UNDERSTOOD. THIS REVIEW FOCUSES ON THE LATEST FINDINGS FROM STUDIES OF THOSE MUTATIONS OF THE MITOCHONDRIAL GENOME WHICH MAY PLAY AN IMPORTANT ROLE IN THE DEVELOPMENT OF ATHEROSCLEROSIS AND WHICH ARE, AT THE SAME TIME, ALSO MARKERS OF MITOCHONDRIAL AGING AND CELL SENESCENCE. 2015 16 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 17 6505 34 TRAINED INNATE IMMUNITY AS A NOVEL MECHANISM LINKING INFECTION AND THE DEVELOPMENT OF ATHEROSCLEROSIS. RATIONALE: THERE IS STRONG EPIDEMIOLOGICAL EVIDENCE FOR AN ASSOCIATION BETWEEN ACUTE AND CHRONIC INFECTIONS AND THE OCCURRENCE OF ATHEROSCLEROTIC CARDIOVASCULAR DISEASE. THE UNDERLYING PATHOPHYSIOLOGICAL MECHANISMS REMAIN UNCLEAR. MONOCYTE-DERIVED MACROPHAGES ARE THE MOST ABUNDANT IMMUNE CELLS IN ATHEROSCLEROTIC PLAQUES. IT HAS RECENTLY BEEN ESTABLISHED THAT MONOCYTES/MACROPHAGES CAN DEVELOP A LONG-LASTING PROINFLAMMATORY PHENOTYPE AFTER BRIEF STIMULATION WITH MICRO-ORGANISMS OR MICROBIAL PRODUCTS, WHICH HAS BEEN TERMED TRAINED IMMUNITY. OBJECTIVE: THE AIM OF THIS STUDY IS TO ASSESS WHETHER TRAINED IMMUNITY MEDIATES THE LINK BETWEEN INFECTIONS AND ATHEROSCLEROTIC CARDIOVASCULAR DISEASE. METHODS AND RESULTS: BRIEF EXPOSURE OF MONOCYTES TO VARIOUS MICRO-ORGANISMS RESULTS IN THE DEVELOPMENT OF MACROPHAGES WITH A PERSISTENT PROINFLAMMATORY PHENOTYPE: THIS REPRESENTS A DE FACTO NONSPECIFIC INNATE IMMUNE MEMORY, WHICH HAS BEEN TERMED TRAINED IMMUNITY. THIS IS MEDIATED BY EPIGENETIC REPROGRAMMING AT THE LEVEL OF HISTONE METHYLATION AND A PROFOUND REWIRING OF INTRACELLULAR METABOLISM. ALTHOUGH THIS MECHANISM OFFERS POWERFUL PROTECTION AGAINST REINFECTION, TRAINED MACROPHAGES DISPLAY AN ATHEROGENIC PHENOTYPE IN TERMS OF CYTOKINE PRODUCTION AND FOAM CELL FORMATION. TRAINED MONOCYTES ARE PRESENT UP TO 3 MONTHS AFTER EXPERIMENTAL INFECTION IN HUMANS. MOREOVER, A TRAINED IMMUNITY PHENOTYPE IS PRESENT IN PATIENTS WITH ESTABLISHED ATHEROSCLEROSIS. CONCLUSIONS: WE PROPOSE THAT TRAINED IMMUNITY PROVIDES THE MISSING MECHANISTIC LINK THAT EXPLAINS THE ASSOCIATION BETWEEN INFECTIONS AND ATHEROSCLEROSIS. THEREFORE, PHARMACOLOGICAL MODULATION OF TRAINED IMMUNITY HAS THE POTENTIAL TO PREVENT INFECTION-RELATED ATHEROSCLEROTIC CARDIOVASCULAR DISEASE IN THE FUTURE. 2018 18 4043 30 MACROPHAGES IN CHRONIC LIVER FAILURE: DIVERSITY, PLASTICITY AND THERAPEUTIC TARGETING. CHRONIC LIVER INJURY RESULTS IN IMMUNE-DRIVEN PROGRESSIVE FIBROSIS, WITH RISK OF CIRRHOSIS DEVELOPMENT AND IMPACT ON MORBIDITY AND MORTALITY. PERSISTENT LIVER CELL DAMAGE AND DEATH CAUSES IMMUNE CELL ACTIVATION AND INFLAMMATION. PATIENTS WITH ADVANCED CIRRHOSIS ADDITIONALLY EXPERIENCE PATHOLOGICAL BACTERIAL TRANSLOCATION, EXPOSURE TO MICROBIAL PRODUCTS AND CHRONIC ENGAGEMENT OF THE IMMUNE SYSTEM. BACTERIAL INFECTIONS HAVE A HIGH INCIDENCE IN CIRRHOSIS, WITH SPONTANEOUS BACTERIAL PERITONITIS BEING THE MOST COMMON, WHILE THE SUBSEQUENT SYSTEMIC INFLAMMATION, ORGAN FAILURE AND IMMUNE DYSREGULATION INCREASE THE MORTALITY RISK. TISSUE-RESIDENT AND RECRUITED MACROPHAGES PLAY A CENTRAL PART IN THE DEVELOPMENT OF INFLAMMATION AND FIBROSIS PROGRESSION. IN THE LIVER, ADIPOSE TISSUE, PERITONEUM AND INTESTINES, DIVERSE MACROPHAGE POPULATIONS EXHIBIT GREAT PHENOTYPIC AND FUNCTIONAL PLASTICITY DETERMINED BY THEIR ONTOGENY, EPIGENETIC PROGRAMMING AND LOCAL MICROENVIRONMENT. THESE CHANGES CAN, AT DIFFERENT TIMES, PROMOTE OR AMELIORATE DISEASE STATES AND THEREFORE REPRESENT POTENTIAL TARGETS FOR MACROPHAGE-DIRECTED THERAPIES. IN THIS REVIEW, WE DISCUSS THE EVIDENCE FOR MACROPHAGE PHENOTYPIC AND FUNCTIONAL ALTERATIONS IN TISSUE COMPARTMENTS DURING THE DEVELOPMENT AND PROGRESSION OF CHRONIC LIVER FAILURE IN DIFFERENT AETIOLOGIES AND HIGHLIGHT THE POTENTIAL OF MACROPHAGE MODULATION AS A THERAPEUTIC STRATEGY FOR LIVER DISEASE. 2021 19 6497 36 TRAINED IMMUNITY IN ATHEROSCLEROTIC CARDIOVASCULAR DISEASE. TRAINED IMMUNITY, ALSO KNOWN AS INNATE IMMUNE MEMORY, IS A PERSISTENT HYPER-RESPONSIVE FUNCTIONAL STATE OF INNATE IMMUNE CELLS. ACCUMULATING EVIDENCE IMPLICATES TRAINED IMMUNITY AS AN UNDERLYING MECHANISM OF CHRONIC INFLAMMATION IN ATHEROSCLEROTIC CARDIOVASCULAR DISEASE. IN THIS CONTEXT, TRAINED IMMUNITY IS INDUCED BY ENDOGENOUS ATHEROSCLEROSIS-PROMOTING FACTORS, SUCH AS MODIFIED LIPOPROTEINS OR HYPERGLYCAEMIA, CAUSING BROAD METABOLIC AND EPIGENETIC REPROGRAMMING OF THE MYELOID CELL COMPARTMENT. IN ADDITION TO TRADITIONAL CARDIOVASCULAR RISK FACTORS, LIFESTYLE FACTORS, INCLUDING UNHEALTHY DIETS, SEDENTARY LIFESTYLE, SLEEP DEPRIVATION AND PSYCHOSOCIAL STRESS, AS WELL AS INFLAMMATORY COMORBIDITIES, HAVE BEEN SHOWN TO ACTIVATE TRAINED IMMUNITY-LIKE MECHANISMS IN BONE MARROW HAEMATOPOIETIC STEM CELLS. IN THIS REVIEW, WE DISCUSS THE MOLECULAR AND CELLULAR MECHANISMS OF TRAINED IMMUNITY, ITS SYSTEMIC REGULATION THROUGH HAEMATOPOIETIC PROGENITOR CELLS IN THE BONE MARROW, AND THE ACTIVATION OF THESE MECHANISMS BY CARDIOVASCULAR DISEASE RISK FACTORS. WE ALSO HIGHLIGHT OTHER TRAINED IMMUNITY FEATURES THAT ARE RELEVANT FOR ATHEROSCLEROTIC CARDIOVASCULAR DISEASE, INCLUDING THE DIVERSE CELL TYPES THAT SHOW MEMORY CHARACTERISTICS AND TRANSGENERATIONAL INHERITANCE OF TRAINED IMMUNITY TRAITS. FINALLY, WE PROPOSE POTENTIAL STRATEGIES FOR THE THERAPEUTIC MODULATION OF TRAINED IMMUNITY TO MANAGE ATHEROSCLEROTIC CARDIOVASCULAR DISEASE. 2023 20 4738 35 NOVEL FIBROBLAST PHENOTYPES IN HOMEOSTASIS AND CHRONIC INFLAMMATION: FROM FUNCTIONS TO POTENTIAL REGULATORS. FIBROBLASTS ARE ESSENTIAL COMPONENTS OF THE STROMA, SUSTAINING A VARIETY OF TISSUES AND BEING KEY TO THE PROCESS OF TISSUE REPAIR AFTER INJURY. THEIR ROLE IN TISSUE REPAIR HAS BEEN ATTRIBUTED TO THEIR ABILITY TO ACQUIRE A CONTRACTILE, EXTRACELLULAR MATRIX-PRODUCING PHENOTYPE KNOWN AS MYOFIBROBLASTS. THIS PROPERTY IS PRIMARILY DEPENDENT ON THEIR RESPONSE TO THE PLEIOTROPIC CYTOKINE TRANSFORMING GROWTH FACTOR-BETA1. UNTIL RECENTLY, THE POTENTIAL ROLE OF FIBROBLASTS IN OTHER HOMEOSTATIC AND DISEASE-RELATED PROCESSES WAS LESS WELL UNDERSTOOD. ALTHOUGH IN VITRO STUDIES INDICATED THAT FIBROBLASTS ARE ABLE TO RESPOND TO AND SECRETE INFLAMMATORY MEDIATORS, DEFINITIVE EVIDENCE OF THEIR CONTRIBUTION TO CHRONIC INFLAMMATION WAS LIMITED. HOWEVER, THE EMERGENCE OF TECHNIQUES THAT ALLOW EXPLORATION OF TISSUES AT THE SINGLE CELL LEVEL HAS CHALLENGED THE PREVIOUS PARADIGMS ON FIBROBLAST IDENTITY AND FUNCTIONS, AND HAS LED TO THE DISCOVERY OF SIGNIFICANT DIVERSITY, SHOWING THE PRESENCE OF FIBROBLASTS WITH ALTERNATE TRANSCRIPTIONAL PROFILES IN A VARIETY OF TISSUES. THESE STUDIES HAVE ALSO SUGGESTED POTENTIAL ROLES OF NOVEL FIBROBLAST SUBTYPES AS REGULATORS OF EPITHELIAL HOMEOSTASIS AND RENEWAL, INFLAMMATORY CELL INFILTRATION AND ACTIVATION, AND ANTIGEN PRESENTATION. HERE, WE PROVIDE A COMPREHENSIVE REVIEW OF THE RECENT LITERATURE ON FIBROBLAST DIVERSITY IN THE DIGESTIVE TRACT, SKIN, LUNGS AND JOINTS. WE ALSO REVIEW EVIDENCE OF THEIR CONTRIBUTION TO THE REGULATION OF HOMEOSTASIS AND CHRONIC INFLAMMATION, AS WELL AS THEIR INTERACTIONS WITH OTHER CELLS IN VARIOUS TISSUE COMPARTMENTS. WE DISCUSS EVIDENCE OF DIFFERENT FACTORS INVOLVED IN THE CONTROL OF FIBROBLAST FUNCTION, ADDRESSING THE ROLE OF VARIOUS CYTOKINES, TRANSCRIPTION FACTORS AND EPIGENETIC CHANGES, AS WELL AS MICROENVIRONMENTAL FACTORS, INCLUDING EXTRACELLULAR MATRIX STIFFNESS, HYPOXIA, AND METABOLIC SHIFTS. 2023