1 6450 118 THERAPEUTIC TARGETS FOR INFLAMMATION-MEDIATED AIRWAY REMODELING IN CHRONIC LUNG DISEASE. ACUTE EXACERBATIONS OF CHRONIC LUNG DISEASE ACCOUNT FOR SUBSTANTIAL MORBIDITY AND HEALTH COSTS. REPEATED INFLAMMATORY EPISODES AND ATTENDANT BRONCHOCONSTRICTION CAUSE STRUCTURAL REMODELING OF THE AIRWAY. REMODELING IS A MULTICELLULAR RESPONSE TO MUCOSAL INJURY THAT RESULTS IN EPITHELIAL CELL-STATE CHANGES, ENHANCED EXTRACELLULAR DEPOSITION, AND EXPANSION OF PRO-FIBROTIC MYOFIBROBLAST POPULATIONS. AREAS COVERED: THIS MANUSCRIPT OVERVIEWS MECHANISTIC STUDIES IDENTIFYING KEY SENTINEL CELL POPULATIONS IN THE AIRWAY AND HOW PATTERN RECOGNITION SIGNALING INDUCES MALADAPTIVE MUCOSAL CHANGES AND AIRWAY REMODELING. STUDIES ELUCIDATING HOW NFKAPPAB COUPLES WITH AN ATYPICAL HISTONE ACETYLTRANSFERASE, BROMODOMAIN-CONTAINING PROTEIN 4 (BRD4) THAT REPROGRAMS MUCOSAL FIBROGENIC RESPONSES, ARE DESCRIBED. THE APPROACHES TO DEVELOPMENT AND CHARACTERIZATION OF SELECTIVE INHIBITORS OF EPIGENETIC REPROGRAMMING ON INNATE INFLAMMATION AND STRUCTURAL REMODELING IN PRECLINICAL MODELS ARE DETAILED. EXPERT COMMENTARY: BRONCHIOLAR CELLS DERIVED FROM SCGB1A1-EXPRESSING PROGENITORS FUNCTION AS MAJOR SENTINEL CELLS OF THE AIRWAY, RESPONSIBLE FOR INITIATING ANTIVIRAL AND AEROALLERGEN RESPONSES. IN THESE SENTINEL CELLS, ACTIVATION OF INNATE INFLAMMATION IS COUPLED TO NEUTROPHILIC RECRUITMENT, MESENCHYMAL TRANSITION AND MYOFIBROBLAST EXPANSION. THERAPEUTICS TARGETING THE NFKB-BRD4 MAY BE EFFICACIOUS IN REDUCING PATHOLOGICAL EFFECTS OF ACUTE EXACERBATIONS IN CHRONIC LUNG DISEASE. 2018 2 5938 52 TARGETING INDUCIBLE EPIGENETIC REPROGRAMMING PATHWAYS IN CHRONIC AIRWAY REMODELING. ALLERGIC ASTHMA IS A CHRONIC INFLAMMATORY AIRWAY DISEASE WHOSE CLINICAL COURSE IS PUNCTUATED BY ACUTE EXACERBATIONS FROM AEROALLERGEN EXPOSURE OR RESPIRATORY VIRUS INFECTIONS. AEROALLERGENS AND RESPIRATORY VIRUSES STIMULATE TOLL-LIKE RECEPTOR (TLR) SIGNALING, PRODUCING OXIDATIVE INJURY AND INFLAMMATION. REPETITIVE EXACERBATIONS PRODUCE COMPLEX MUCOSAL ADAPTATIONS, CELL-STATE CHANGES, AND STRUCTURAL REMODELING. THESE STRUCTURAL CHANGES PRODUCE SUBSTANTIAL MORBIDITY, DECREASE LUNG CAPACITY, AND IMPAIR QUALITY OF LIFE. WE WILL REVIEW RECENT SYSTEMS-LEVEL STUDIES THAT PROVIDE FUNDAMENTAL NEW INSIGHTS INTO HOW REPETITIVE ACTIVATION OF INNATE SIGNALING PATHWAYS PRODUCE EPIGENETIC 'TRAINING' TO INDUCE ADAPTIVE EPITHELIAL RESPONSES. OXIDATIVE STRESS PRODUCED DOWNSTREAM OF TLR SIGNALING INDUCES TRANSIENT OXIDATION OF GUANINE BASES IN THE REGULATORY REGIONS OF INFLAMMATORY GENES. THE EPIGENETIC MARK 8-OXOG IS BOUND BY A PLEIOTROPIC DNA REPAIR ENZYME, 8-OXOGUANINE DNA GLYCOSYLASE (OGG1), WHICH INDUCES CONFORMATIONAL CHANGES IN ADJACENT DNA TO RECRUIT THE NFKAPPAB.BROMODOMAIN-CONTAINING PROTEIN 4 (BRD4) COMPLEX. THE NFKAPPAB.BRD4 COMPLEX NOT ONLY PLAYS A CENTRAL ROLE IN INFLAMMATION, BUT ALSO TRIGGERS MESENCHYMAL TRANSITION AND EXTRACELLULAR MATRIX REMODELING. SMALL MOLECULE INHIBITORS OF OGG1-8-OXOG BINDING AND BRD4-ACETYLATED HISTONE INTERACTION HAVE BEEN DEVELOPED. WE PRESENT STUDIES DEMONSTRATING EFFICACY OF THESE IN REDUCING AIRWAY INFLAMMATION IN PRECLINICAL MODELS. TARGETING INDUCIBLE EPIGENETIC REPROGRAMMING PATHWAY SHOWS PROMISE FOR THERAPEUTICS IN REVERSING AIRWAY REMODELING IN A VARIETY OF CHRONIC AIRWAY DISEASES. 2019 3 2933 39 GENESIS OF THE MYOFIBROBLAST IN LUNG INJURY AND FIBROSIS. TISSUE INJURY INCITES A REPAIR RESPONSE WITH A KEY MESENCHYMAL COMPONENT THAT PROVIDES THE ESSENTIAL CONNECTIVE TISSUE FOR SUBSEQUENT REGENERATION OR PATHOLOGICAL FIBROSIS. THE FIBROBLAST IS THE MAJOR MESENCHYMAL CELL TYPE TO BE IMPLICATED IN THIS CONNECTIVE TISSUE RESPONSE, AND IT IS IN ITS ACTIVATED OR DIFFERENTIATED FORM THAT IT PARTICIPATES IN THE REPAIR PROCESS. THE MYOFIBROBLAST REPRESENTS SUCH AN ACTIVATED MESENCHYMAL CELL AND IS A KEY SOURCE OF EXTRACELLULAR MATRIX AND INFLAMMATORY/FIBROGENIC CYTOKINES AS WELL AS PARTICIPATING IN WOUND CONTRACTION. ALTHOUGH SUCCESSFUL HEALING RESULTS IN GRADUAL DISAPPEARANCE OF MYOFIBROBLASTS, THEIR PERSISTENCE IS ASSOCIATED WITH CHRONIC AND PROGRESSIVE FIBROSIS. THUS, ELUCIDATION OF THE MECHANISM INVOLVED IN THE GENESIS OF THE MYOFIBROBLAST SHOULD PROVIDE INSIGHT INTO BOTH PATHOGENESIS OF CHRONIC FIBROTIC DISEASES AND THERAPEUTIC STRATEGIES FOR THEIR MANAGEMENT AND CONTROL. ALTHOUGH THE FIBROBLAST IS A WELL-DOCUMENTED PROGENITOR CELL FOR THE MYOFIBROBLAST, RECENT STUDIES HAVE SUGGESTED ADDITIONAL PRECURSOR CELLS THAT HAVE THE POTENTIAL TO GIVE RISE TO THE MYOFIBROBLAST. MANY OF THE STUDIES FOCUSED ON MECHANISMS AND FACTORS THAT REGULATE INDUCTION OF ALPHA-SMOOTH MUSCLE ACTIN EXPRESSION, A KEY AND COMMONLY USED MARKER OF THE MYOFIBROBLAST. THESE REVEAL COMPLEX AND MULTIFACTORIAL MECHANISMS INVOLVING TRANSCRIPTIONAL AND EPIGENETIC REGULATION AND IMPLICATING DIVERSE CELL-SIGNALING PATHWAYS, INCLUDING THOSE ACTIVATED BY THE POTENT FIBROGENIC CYTOKINE TRANSFORMING GROWTH FACTOR BETA. DESPITE THESE EXTENSIVE STUDIES, MANY ASPECTS REMAIN POORLY UNDERSTOOD, WITH THE SUGGESTION THAT ADDITIONAL NOVEL MECHANISMS REMAIN TO BE DISCOVERED. FUTURE STUDIES WITH THE HELP OF NEWLY DEVELOPED TECHNICAL ADVANCEMENTS SHOULD EXPEDITE DISCOVERY IN THIS DIRECTION. 2012 4 5472 31 RESPIRATORY VIRAL INFECTIONS IN EXACERBATION OF CHRONIC AIRWAY INFLAMMATORY DISEASES: NOVEL MECHANISMS AND INSIGHTS FROM THE UPPER AIRWAY EPITHELIUM. RESPIRATORY VIRUS INFECTION IS ONE OF THE MAJOR SOURCES OF EXACERBATION OF CHRONIC AIRWAY INFLAMMATORY DISEASES. THESE EXACERBATIONS ARE ASSOCIATED WITH HIGH MORBIDITY AND EVEN MORTALITY WORLDWIDE. THE CURRENT UNDERSTANDING ON VIRAL-INDUCED EXACERBATIONS IS THAT VIRAL INFECTION INCREASES AIRWAY INFLAMMATION WHICH AGGRAVATES DISEASE SYMPTOMS. RECENT ADVANCES IN IN VITRO AIR-LIQUID INTERFACE 3D CULTURES, ORGANOID CULTURES AND THE USE OF NOVEL HUMAN AND ANIMAL CHALLENGE MODELS HAVE EVOKED NEW UNDERSTANDINGS AS TO THE MECHANISMS OF VIRAL EXACERBATIONS. IN THIS REVIEW, WE WILL FOCUS ON RECENT NOVEL FINDINGS THAT ELUCIDATE HOW RESPIRATORY VIRAL INFECTIONS ALTER THE EPITHELIAL BARRIER IN THE AIRWAYS, THE UPPER AIRWAY MICROBIAL ENVIRONMENT, EPIGENETIC MODIFICATIONS INCLUDING MIRNA MODULATION, AND OTHER CHANGES IN IMMUNE RESPONSES THROUGHOUT THE UPPER AND LOWER AIRWAYS. FIRST, WE REVIEWED THE PREVALENCE OF DIFFERENT RESPIRATORY VIRAL INFECTIONS IN CAUSING EXACERBATIONS IN CHRONIC AIRWAY INFLAMMATORY DISEASES. SUBSEQUENTLY WE ALSO SUMMARIZED HOW RECENT MODELS HAVE EXPANDED OUR APPRECIATION OF THE MECHANISMS OF VIRAL-INDUCED EXACERBATIONS. FURTHER WE HIGHLIGHTED THE IMPORTANCE OF THE VIROME WITHIN THE AIRWAY MICROBIOME ENVIRONMENT AND ITS IMPACT ON SUBSEQUENT BACTERIAL INFECTION. THIS REVIEW CONSOLIDATES THE UNDERSTANDING OF VIRAL INDUCED EXACERBATION IN CHRONIC AIRWAY INFLAMMATORY DISEASES AND INDICATES PATHWAYS THAT MAY BE TARGETED FOR MORE EFFECTIVE MANAGEMENT OF CHRONIC INFLAMMATORY DISEASES. 2020 5 6687 37 VALIDATION OF THE EPIGENETIC READER BROMODOMAIN-CONTAINING PROTEIN 4 (BRD4) AS A THERAPEUTIC TARGET FOR TREATMENT OF AIRWAY REMODELING. STRUCTURAL REMODELING IS CENTRAL TO THE INITIATION AND PROGRESSION OF MANY CHRONIC LUNG DISEASES, REPRESENTING AN IMPORTANT UNMET NEED. WE EXAMINE THE EVIDENCE SUPPORTING BROMODOMAIN-CONTAINING PROTEIN 4 (BRD4) AS A VALIDATED BIOLOGICAL TARGET FOR TREATMENT OF AIRWAY REMODELING. IN EPITHELIAL CELLS AND FIBROBLASTS, BRD4 SERVES AS A SCAFFOLD FOR CHROMATIN REMODELING COMPLEXES IN ACTIVE SUPER-ENHANCERS. IN RESPONSE TO INFLAMMATORY STIMULI, BRD4 IS REPOSITIONED TO INNATE AND MESENCHYMAL GENES ACTIVATING THEIR PRODUCTION. PROOF-OF-CONCEPT STUDIES SHOW PROMISING BENEFIT OF SELECTIVE BRD4 INHIBITORS IN DISRUPTING EPITHELIAL MESENCHYMAL TRANSITION AND MYOFIBROBLAST TRANSITION IN DIVERSE MODELS OF LUNG INJURY. RECENT IDENTIFICATION OF BIOMARKERS OF BRD4 PROVIDES A BASIS FOR FURTHER DRUG DEVELOPMENT FOR APPLICATION IN VIRAL-INDUCED AIRWAY INFLAMMATION, COPD AND INTERSTITIAL LUNG DISEASES. 2020 6 6223 32 THE LEADING ROLE OF EPITHELIAL CELLS IN THE PATHOGENESIS OF IDIOPATHIC PULMONARY FIBROSIS. IDIOPATHIC PULMONARY FIBROSIS (IPF) IS A RELENTLESSLY PROGRESSIVE AND DEVASTATING INTERSTITIAL LUNG DISEASE OF UNKNOWN ETIOLOGY, WHERE THE NORMAL LUNG ARCHITECTURE IS LOST AND REPLACED BY FIBROTIC TISSUE LEADING TO AN IRREVERSIBLE AND PROGRESSIVE RESPIRATORY INSUFFICIENCY. HISTORICALLY, IPF WAS CONSIDERED A CHRONIC INFLAMMATORY DISORDER, WHICH GRADUALLY PROGRESSED TO ESTABLISHED FIBROSIS. HOWEVER, STRONG CLINICAL AND EXPERIMENTAL EVIDENCE INDICATES THAT THE DISEASE REPRESENTS AN EPITHELIAL-DRIVEN DISORDER WHICH RESULTS FROM A COMPLEX INTERPLAY OF GENETIC AND ENVIRONMENTAL RISK FACTORS, AGING-ASSOCIATED PROCESSES AND A PROFIBROTIC EPIGENETIC REPROGRAMMING. THE CONVERGENCE OF THESE FACTORS RESULTS IN THE ABERRANT ACTIVATION OF EPITHELIAL CELLS THAT INITIATE THE DEVELOPMENT OF THE DISEASE, PRODUCING VIRTUALLY ALL THE MEDIATORS THAT PARTICIPATE IN THE MIGRATION, PROLIFERATION AND ACTIVATION OF FIBROBLASTS, THEIR DIFFERENTIATION TO MYOFIBROBLASTS AND THE EXCESSIVE AND CHAOTIC SECRETION OF EXTRACELLULAR MATRIX PROTEINS. ALTHOUGH PROGRESS HAS BEEN MADE IN UNDERSTANDING THE CAUSES AND CONSEQUENCES OF THIS ABNORMAL BEHAVIOR OF DISTAL AIRWAYS AND ALVEOLAR EPITHELIUM, THE MECHANISMS THAT INITIATE AND PERPETUATE THE VICIOUS CIRCLE OF MULTIDIRECTIONAL ABNORMAL COMMUNICATIONS BETWEEN THE EPITHELIUM AND FIBROBLASTS AND OTHER RESIDENT CELLS HAVE NOT BEEN ELUCIDATED. IN THIS REVIEW, WE DISCUSS THE ROLE OF EPITHELIAL CELLS AND THE MECHANISMS UNDERLYING THE FIBROTIC RESPONSE IN IPF, AND HIGHLIGHT SOME PROMISING THERAPEUTIC TARGETS FOR THESE CELLS. 2020 7 4738 30 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 8 6005 29 THE AIRWAY EPITHELIUM-A CENTRAL PLAYER IN ASTHMA PATHOGENESIS. ASTHMA IS A CHRONIC INFLAMMATORY AIRWAY DISEASE CHARACTERIZED BY VARIABLE AIRFLOW OBSTRUCTION IN RESPONSE TO A WIDE RANGE OF EXOGENOUS STIMULI. THE AIRWAY EPITHELIUM IS THE FIRST LINE OF DEFENSE AND PLAYS AN IMPORTANT ROLE IN INITIATING HOST DEFENSE AND CONTROLLING IMMUNE RESPONSES. INDEED, INCREASING EVIDENCE INDICATES A RANGE OF ABNORMALITIES IN VARIOUS ASPECTS OF EPITHELIAL BARRIER FUNCTION IN ASTHMA. A CENTRAL PART OF THIS IMPAIRMENT IS A DISRUPTION OF THE AIRWAY EPITHELIAL LAYER, ALLOWING INHALED SUBSTANCES TO PASS MORE EASILY INTO THE SUBMUCOSA WHERE THEY MAY INTERACT WITH IMMUNE CELLS. FURTHERMORE, MANY OF THE IDENTIFIED SUSCEPTIBILITY GENES FOR ASTHMA ARE EXPRESSED IN THE AIRWAY EPITHELIUM. THIS REVIEW FOCUSES ON THE BIOLOGY OF THE AIRWAY EPITHELIUM IN HEALTH AND ITS PATHOBIOLOGY IN ASTHMA. WE WILL SPECIFICALLY DISCUSS EXTERNAL TRIGGERS SUCH AS ALLERGENS, VIRUSES AND ALARMINS AND THE EFFECT OF TYPE 2 INFLAMMATORY RESPONSES ON AIRWAY EPITHELIAL FUNCTION IN ASTHMA. WE WILL ALSO DISCUSS EPIGENETIC MECHANISMS RESPONDING TO EXTERNAL STIMULI ON THE LEVEL OF TRANSCRIPTIONAL AND POSTTRANSCRIPTIONAL REGULATION OF GENE EXPRESSION, AS WELL THE AIRWAY EPITHELIUM AS A POTENTIAL TREATMENT TARGET IN ASTHMA. 2020 9 1876 29 EMERGING ROLES FOR EPIGENETIC PROGRAMMING IN THE CONTROL OF INFLAMMATORY SIGNALING INTEGRATION IN HEATH AND DISEASE. MACROPHAGES AND DENDRITIC CELLS INITIATE THE INNATE IMMUNE RESPONSE TO INFECTION AND INJURY AND CONTRIBUTE TO INFLAMMATORY SIGNALING TO MAINTAIN THE HOMEOSTASIS OF VARIOUS TISSUES, WHICH INCLUDES RESIDENT MACROPHAGES FOR THE ELIMINATION OF INVADING MICROORGANISMS AND TISSUE DAMAGE. INAPPROPRIATE INFLAMMATORY SIGNALING CAN LEAD TO PERSISTENT INFLAMMATION AND FURTHER DEVELOP INTO AUTOIMMUNE AND INFLAMMATION-ASSOCIATED DISEASES. INFLAMMATORY SIGNALING PATHWAYS HAVE BEEN WELL CHARACTERIZED, BUT HOW THESE SIGNALING PATHWAYS ARE CONVERTED INTO SUSTAINED AND DIVERSE PATTERNS OF EXPRESSION OF CYTOKINES, CHEMOKINES, AND OTHER GENES IN RESPONSE TO ENVIRONMENTAL CHALLENGES IS UNCLEAR. EMERGING EVIDENCE SUGGESTS THE IMPORTANT ROLE OF EPIGENETIC MECHANISMS IN FINELY TUNING THE OUTCOME OF THE HOST INNATE IMMUNE RESPONSE. AN UNDERSTANDING OF EPIGENETIC REGULATION OF INNATE IMMUNE CELL IDENTITY AND FUNCTION WILL ENABLE THE IDENTIFICATION OF THE MECHANISM BETWEEN GENE-SPECIFIC HOST DEFENSES AND INFLAMMATORY DISEASE AND WILL ALSO ALLOW FOR EXPLORATION OF THE PROGRAM OF INNATE IMMUNE MEMORY IN HEALTH AND DISEASE. THIS INFORMATION COULD BE USED TO DEVELOP THERAPEUTIC AGENTS TO ENHANCE THE HOST RESPONSE, PREVENTING CHRONIC INFLAMMATION THROUGH PRESERVING TISSUES AND SIGNALING INTEGRITY. 2017 10 2299 38 EPIGENETIC REGULATION OF AIRWAY EPITHELIUM IMMUNE FUNCTIONS IN ASTHMA. ASTHMA IS A CHRONIC INFLAMMATORY DISEASE OF THE RESPIRATORY TRACT CHARACTERIZED BY RECURRENT BREATHING PROBLEMS RESULTING FROM AIRWAY OBSTRUCTION AND HYPERRESPONSIVENESS. HUMAN AIRWAY EPITHELIUM PLAYS AN IMPORTANT ROLE IN THE INITIATION AND CONTROL OF THE IMMUNE RESPONSES TO DIFFERENT TYPES OF ENVIRONMENTAL FACTORS CONTRIBUTING TO ASTHMA PATHOGENESIS. USING PATTERN RECOGNITION RECEPTORS AIRWAY EPITHELIUM SENSES EXTERNAL STIMULI, SUCH AS ALLERGENS, MICROBES, OR POLLUTANTS, AND SUBSEQUENTLY SECRETES ENDOGENOUS DANGER SIGNALING MOLECULES ALARMING AND ACTIVATING DENDRITIC CELLS. HENCE, AIRWAY EPITHELIAL CELLS NOT ONLY MEDIATE INNATE IMMUNE RESPONSES BUT ALSO BRIDGE THEM WITH ADAPTIVE IMMUNE RESPONSES INVOLVING T AND B CELLS THAT PLAY A CRUCIAL ROLE IN THE PATHOGENESIS OF ASTHMA. THE EFFECTS OF ENVIRONMENTAL FACTORS ON THE DEVELOPMENT OF ASTHMA ARE MEDIATED, AT LEAST IN PART, BY EPIGENETIC MECHANISMS. THOSE COMPRISE CLASSICAL EPIGENETICS INCLUDING DNA METHYLATION AND HISTONE MODIFICATIONS AFFECTING TRANSCRIPTION, AS WELL AS MICRORNAS INFLUENCING TRANSLATION. THE COMMON FEATURE OF SUCH MECHANISMS IS THAT THEY REGULATE GENE EXPRESSION WITHOUT AFFECTING THE NUCLEOTIDE SEQUENCE OF THE GENOMIC DNA. EPIGENETIC MECHANISMS PLAY A PIVOTAL ROLE IN THE REGULATION OF DIFFERENT CELL POPULATIONS INVOLVED IN ASTHMA PATHOGENESIS, WITH THE REMARKABLE EXAMPLE OF T CELLS. RECENTLY, HOWEVER, THERE IS INCREASING EVIDENCE THAT EPIGENETIC MECHANISMS ARE ALSO CRUCIAL FOR THE REGULATION OF AIRWAY EPITHELIAL CELLS, ESPECIALLY IN THE CONTEXT OF EPIGENETIC TRANSFER OF ENVIRONMENTAL EFFECTS CONTRIBUTING TO ASTHMA PATHOGENESIS. IN THIS REVIEW, WE SUMMARIZE THE ACCUMULATING EVIDENCE FOR THIS VERY IMPORTANT ASPECT OF AIRWAY EPITHELIAL CELL PATHOBIOLOGY. 2020 11 5932 26 TARGETING EPIGENETIC REGULATORS FOR INFLAMMATION: MECHANISMS AND INTERVENTION THERAPY. EMERGING EVIDENCE INDICATES THAT RESOLUTION OF INFLAMMATION IS A CRITICAL AND DYNAMIC ENDOGENOUS PROCESS FOR HOST TISSUES DEFENDING AGAINST EXTERNAL INVASIVE PATHOGENS OR INTERNAL TISSUE INJURY. IT HAS LONG BEEN KNOWN THAT AUTOIMMUNE DISEASES AND CHRONIC INFLAMMATORY DISORDERS ARE CHARACTERIZED BY DYSREGULATED IMMUNE RESPONSES, LEADING TO EXCESSIVE AND UNCONTROL TISSUE INFLAMMATION. THE DYSREGULATION OF EPIGENETIC ALTERATIONS INCLUDING DNA METHYLATION, POSTTRANSLATIONAL MODIFICATIONS TO HISTONE PROTEINS, AND NONCODING RNA EXPRESSION HAS BEEN IMPLICATED IN A HOST OF INFLAMMATORY DISORDERS AND THE IMMUNE SYSTEM. THE INFLAMMATORY RESPONSE IS CONSIDERED AS A CRITICAL TRIGGER OF EPIGENETIC ALTERATIONS THAT IN TURN INTERCEDE INFLAMMATORY ACTIONS. THUS, UNDERSTANDING THE MOLECULAR MECHANISM THAT DICTATES THE OUTCOME OF TARGETING EPIGENETIC REGULATORS FOR INFLAMMATORY DISEASE IS REQUIRED FOR INFLAMMATION RESOLUTION. IN THIS ARTICLE, WE ELUCIDATE THE CRITICAL ROLE OF THE NUCLEAR FACTOR-KAPPAB SIGNALING PATHWAY, JAK/STAT SIGNALING PATHWAY, AND THE NLRP3 INFLAMMASOME IN CHRONIC INFLAMMATORY DISEASES. AND WE FORMULATE THE RELATIONSHIP BETWEEN INFLAMMATION, CORONAVIRUS DISEASE 2019, AND HUMAN CANCERS. ADDITIONALLY, WE REVIEW THE MECHANISM OF EPIGENETIC MODIFICATIONS INVOLVED IN INFLAMMATION AND INNATE IMMUNE CELLS. ALL THAT MATTERS IS THAT WE PROPOSE AND DISCUSS THE REJUVENATION POTENTIAL OF INTERVENTIONS THAT TARGET EPIGENETIC REGULATORS AND REGULATORY MECHANISMS FOR CHRONIC INFLAMMATION-ASSOCIATED DISEASES TO IMPROVE THERAPEUTIC OUTCOMES. 2022 12 2344 24 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 13 3535 27 IMMUNE AND GENETIC MECHANISMS IN COPD: POSSIBLE TARGETS FOR THERAPEUTIC INTERVENTIONS. GENETIC, IMMUNE AND ENVIRONMENTAL INTERACTIONS ARE KEY ELEMENTS FOR THE DEVELOPMENT OF COPD. CIGARETTE SMOKING IS CONSIDERED THE PRIMARY RISK FACTOR INITIATING INFLAMMATORY CASCADES IN GENETICALLY SUSCEPTIBLE INDIVIDUALS. THE "DANGER SIGNALS" ELICITED BY THE INJURED CELLS OF NON-SPECIFIC IMMUNITY INDUCE THE DOWNSTREAM ACTIVATION OF PROINFLAMMATORY CASCADES AND ANTIGEN-SPECIFIC ADAPTIVE IMMUNE RESPONSES. THE PRODUCED OXIDATIVE STRESS FURTHER DAMAGES THE LUNG LEADING TO ACQUIRED GENETIC CHANGES (HISTONE DEACETYLATION, MICROSATELLITE DNA INSTABILITY, DNA METHYLATION, TELOMERE SHORTENING, MIRNA ALTERATIONS) DUE TO AN INEFFICIENT DNA REPAIR MACHINERY. ON THE OTHER HAND, AUGMENTED APOPTOSIS, IMPAIRED EFFEROCYTOSIS AND ABNORMAL TISSUE REMODELING CONTRIBUTE TO THE CHRONIC INFLAMMATORY RESPONSE AND TISSUE DESTRUCTION IN COPD. THIS REVIEW FOCUSES ON THE ROLE OF GENETIC, EPIGENETIC AND IMMUNE MECHANISMS IN THE DEVELOPMENT OF COPD IN ORDER TO PUT FORWARD POSSIBLE PROGNOSTIC AND THERAPEUTIC TARGETS. 2013 14 4953 39 PATHOGENESIS OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) INDUCED BY CIGARETTE SMOKE. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IS A COMMON RESPIRATORY DISEASE THAT IS CHARACTERIZED BY FUNCTIONAL AND STRUCTURAL ALTERATIONS PRIMARILY CAUSED BY LONG-TERM INHALATION OF HARMFUL PARTICLES. CIGARETTE SMOKE (CS) INDUCES AIRWAY INFLAMMATION IN COPD, WHICH IS KNOWN TO PERSIST EVEN AFTER SMOKING CESSATION. THIS REVIEW DISCUSSES THE BASIC PATHOGENESIS OF COPD, WITH PARTICULAR FOCUS ON AN ENDOGENOUS PROTECTIVE MECHANISM AGAINST OXIDATIVE STRESS VIA NRF2, ALTERED IMMUNE RESPONSE OF THE AIRWAY INFLAMMATORY CELLS, EXAGGERATED CELLULAR SENESCENCE OF THE LUNG STRUCTURAL CELLS, AND CELL DEATH WITH EXPANDED INFLAMMATION. RECENTLY, CS-INDUCED MITOCHONDRIA AUTOPHAGY IS REPORTED TO INITIATE PROGRAMMED NECROSIS (NECROPTOSIS). NECROPTOSIS IS A NEW CONCEPT OF CELL DEATH WHICH IS DRIVEN BY A DEFINED MOLECULAR PATHWAY ALONG WITH EXAGGERATED INFLAMMATION. THIS NEW CELL DEATH MECHANISM IS OF IMPORTANCE DUE TO ITS ABILITY TO PRODUCE MORE INFLAMMATORY SUBSTANCES DURING THE PROCESS OF EPITHELIAL DEATH, CONTRIBUTING TO PERSISTENT AIRWAY INFLAMMATION THAT CANNOT BE EXPLAINED BY APOPTOSIS-DERIVED CELL DEATH. AUTOPHAGY IS AN AUTO-CELL COMPONENT DEGRADATION SYSTEM EXECUTED BY LYSOSOMES THAT CONTROLS PROTEIN AND ORGANELLE DEGRADATION FOR SUCCESSFUL HOMEOSTASIS. AS WELL AS IN THE PROCESS OF NECROPTOSIS, AUTOPHAGY IS ALSO OBSERVED DURING CELLULAR SENESCENCE. AGING OF THE LUNGS RESULTS IN THE ACQUISITION OF SENESCENCE-ASSOCIATED SECRETORY PHENOTYPES (SASP) THAT ARE KNOWN TO SECRETE INFLAMMATORY CYTOKINES, CHEMOKINES, GROWTH FACTORS, AND MATRIX METALLOPROTEINASES RESULTING IN CHRONIC LOW-GRADE INFLAMMATION. IN FUTURE RESEARCH, WE INTEND TO HIGHLIGHT THE GENETIC AND EPIGENETIC APPROACHES THAT CAN FACILITATE THE UNDERSTANDING OF DISEASE SUSCEPTIBILITY. THE GOAL OF PRECISION MEDICINE IS TO ESTABLISH MORE ACCURATE DIAGNOSIS AND TREATMENT METHODS BASED ON THE PATIENT-SPECIFIC PATHOGENIC CHARACTERISTICS. THIS REVIEW PROVIDES INSIGHTS INTO CS-INDUCED COPD PATHOGENESIS, WHICH CONTRIBUTES TO A VERY COMPLEX DISEASE. INVESTIGATING THE MECHANISM OF DEVELOPING COPD, ALONG WITH THE AVAILABILITY OF THE PARTICULAR INHIBITORS, WILL LEAD TO NEW THERAPEUTIC APPROACHES IN COPD TREATMENT. 2019 15 5534 32 ROLE OF AIRWAY EPITHELIAL CELLS IN THE DEVELOPMENT OF DIFFERENT ASTHMA PHENOTYPES. THE TERM (BRONCHIAL) ASTHMA DESCRIBES A DISORDER SYNDROME THAT COMPRISES SEVERAL DISEASE PHENOTYPES, ALL CHARACTERIZED BY CHRONIC INFLAMMATION IN THE BRONCHIAL EPITHELIUM, WITH A VARIETY OF SUBSEQUENT FUNCTIONAL CONSEQUENCES. THUS, THE EPITHELIUM IN THE CONDUCTING AIRWAYS IS THE MAIN LOCALIZATION OF THE COMPLEX PATHOLOGICAL CHANGES IN THE DISEASE. IN THIS REGARD, BRONCHIAL EPITHELIAL CELLS ARE NOT PASSIVELY AFFECTED BY INFLAMMATORY MECHANISMS INDUCED BY IMMUNOLOGICAL PROCESSES BUT RATHER ACTIVELY INVOLVED IN ALL STEPS OF DISEASE DEVELOPMENT FROM INITIATION AND PERPETUATION TO CHRONIFICATION. IN RECENT YEARS IT TURNED OUT THAT BRONCHIAL EPITHELIAL CELLS SHOW A HIGH LEVEL OF STRUCTURAL AND FUNCTIONAL DIVERSITY AND PLASTICITY WITH EPIGENETIC MECHANISMS PLAYING A CRUCIAL ROLE IN THE REGULATION OF THESE PROCESSES. THUS, IT IS QUITE REASONABLE THAT DIFFERENTIAL FUNCTIONAL ACTIVITIES OF THE BRONCHIAL EPITHELIUM ARE INVOLVED IN THE DEVELOPMENT OF DIFFERENT ASTHMA PHENOTYPES AND/OR STAGES OF DISEASE. THE CURRENT KNOWLEDGE ON THIS TOPIC WILL BE DISCUSSED IN THIS REVIEW ARTICLE. 2020 16 6212 31 THE INTERPLAY OF THE GENETIC ARCHITECTURE, AGING, AND ENVIRONMENTAL FACTORS IN THE PATHOGENESIS OF IDIOPATHIC PULMONARY FIBROSIS. IDIOPATHIC PULMONARY FIBROSIS (IPF) IS A CHRONIC FIBROSING LUNG DISEASE OF INDETERMINATE ETIOLOGY AND LIMITED THERAPEUTIC OPTIONS. THE INITIATION, DEVELOPMENT, AND PROGRESSION OF IPF ARE INFLUENCED BY GENETIC PREDISPOSITION, AGING, AND HOST AND ENVIRONMENTAL FACTORS, BUT THE MAGNITUDE OF THE CONTRIBUTION OF EACH OF THEM AND THE SEQUENCE OF THE PATHOGENIC EVENTS ARE UNCERTAIN. CURRENT EVIDENCE INDICATES THAT ACCUMULATED ENVIRONMENTAL EXPOSURES IN A GENETICALLY PREDISPOSED INDIVIDUAL, USUALLY OVER 60 YEARS OF AGE, LEADS TO PHENOTYPIC AND FUNCTIONAL ALTERATIONS OF THE LUNG EPITHELIUM. ABERRANT ACTIVATION OF EPITHELIAL CELLS RESULTS, THROUGH A COMPLEX RELEASE OF NUMEROUS MEDIATORS, IN THE LOCAL EXPANSION OF PECULIAR SUBSETS OF AGGRESSIVE FIBROBLASTS AND MYOFIBROBLASTS, WHICH ARE CRUCIAL EFFECTOR CELLS OF FIBROTIC REMODELING AND LOSS OF THE NORMAL LUNG ARCHITECTURE AND FUNCTION. PROGRESSIVE INCREASE OF THE MECHANICAL STIFFNESS ACTIVATES CELL-AUTONOMOUS AND MATRIX-DEPENDENT PROCESSES CONTRIBUTING TO THE PERPETUATION OF THE FIBROTIC RESPONSE. THIS PERSPECTIVE PROVIDES AN INTEGRAL OVERVIEW OF THE MAJOR RISK FACTORS UNDERPINNING THE PATHOGENESIS OF IPF, INCLUDING GENE VARIANTS, AGING ALTERATIONS, ENVIRONMENTAL FACTORS, HOST RISK FACTORS, AND EPIGENETIC REPROGRAMMING. 2021 17 3703 23 INFLAMMATORY SIGNALLING AS MEDIATOR OF EPIGENETIC MODULATION IN TISSUE-SPECIFIC CHRONIC INFLAMMATION. RECENT SUCCESSES OF THERAPEUTIC INTERVENTION IN CHRONIC INFLAMMATORY DISEASES USING EPIGENETIC MODIFIERS SUCH AS HISTONE DEACETYLASE INHIBITORS AND INHIBITORS OF DNA METHYLATION SUGGEST THAT EPIGENETIC REPROGRAMMING PLAYS A ROLE IN THE AETIOLOGY OF THESE DISEASES. THE EPIGENETIC SIGNATURE OF A GIVEN IMMUNE CELL IS REFLECTED IN THE HISTORY OF MODIFICATIONS FROM DIFFERENT SIGNALS THE CELL HAS BEEN SUBJECTED TO DURING DIFFERENTIATION. LIKE OTHER CELLS, DIFFERENTIATING IMMUNE CELLS ARE DEPENDENT ON A COMPLEX COMBINATION OF INTER- AND INTRACELL SIGNALLING AS WELL AS TRANSCRIPTION MACHINERIES TO MODULATE THEIR EPIGENOMES IN ORDER TO MEDIATE DIFFERENTIATION. DESPITE EXTENSIVE RESEARCH INTO THESE PROCESSES, THE LINK BETWEEN CELLULAR SIGNALLING AND EPIGENETIC MODULATION REMAINS POORLY UNDERSTOOD. HERE, WE REVIEW RECENT PROGRESS AND DISCUSS KEY FACTORS DRIVING EPIGENETIC MODULATION IN CHRONIC INFLAMMATION. 2009 18 689 42 BRD4 AS A THERAPEUTIC TARGET IN PULMONARY DISEASES. BROMODOMAIN AND EXTRA-TERMINAL DOMAIN (BET) PROTEINS ARE EPIGENETIC MODULATORS THAT REGULATE GENE TRANSCRIPTION THROUGH INTERACTING WITH ACETYLATED LYSINE RESIDUES OF HISTONE PROTEINS. BET PROTEINS HAVE MULTIPLE ROLES IN REGULATING KEY CELLULAR FUNCTIONS SUCH AS CELL PROLIFERATION, DIFFERENTIATION, INFLAMMATION, OXIDATIVE AND REDOX BALANCE, AND IMMUNE RESPONSES. AS A RESULT, BET PROTEINS HAVE BEEN FOUND TO BE ACTIVELY INVOLVED IN A BROAD RANGE OF HUMAN LUNG DISEASES INCLUDING ACUTE LUNG INFLAMMATION, ASTHMA, PULMONARY ARTERIAL HYPERTENSION, PULMONARY FIBROSIS, AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). DUE TO THE IDENTIFICATION OF SPECIFIC SMALL MOLECULAR INHIBITORS OF BET PROTEINS, TARGETING BET IN THESE LUNG DISEASES HAS BECOME AN AREA OF INCREASING INTEREST. EMERGING EVIDENCE HAS DEMONSTRATED THE BENEFICIAL EFFECTS OF BET INHIBITORS IN PRECLINICAL MODELS OF VARIOUS HUMAN LUNG DISEASES. THIS IS, IN GENERAL, LARGELY RELATED TO THE ABILITY OF BET PROTEINS TO BIND TO PROMOTERS OF GENES THAT ARE CRITICAL FOR INFLAMMATION, DIFFERENTIATION, AND BEYOND. BY MODULATING THESE CRITICAL GENES, BET PROTEINS ARE INTEGRATED INTO THE PATHOGENESIS OF DISEASE PROGRESSION. THE INTRINSIC HISTONE ACETYLTRANSFERASE ACTIVITY OF BROMODOMAIN-CONTAINING PROTEIN 4 (BRD4) IS OF PARTICULAR INTEREST, SEEMS TO ACT INDEPENDENTLY OF ITS BROMODOMAIN BINDING ACTIVITY, AND HAS IMPLICATION IN SOME CONTEXTS. IN THIS REVIEW, WE PROVIDE A BRIEF OVERVIEW OF THE RESEARCH ON BET PROTEINS WITH A FOCUS ON BRD4 IN SEVERAL MAJOR HUMAN LUNG DISEASES, THE UNDERLYING MOLECULAR MECHANISMS, AS WELL AS FINDINGS OF TARGETING BET PROTEINS USING PHARMACEUTICAL INHIBITORS IN DIFFERENT LUNG DISEASES PRECLINICALLY. 2023 19 6131 28 THE EPIGENETIC REGULATION OF WOUND HEALING. SIGNIFICANCE: EPIGENETIC REGULATORY MECHANISMS ARE ESSENTIAL FOR EPIDERMAL HOMEOSTASIS AND CONTRIBUTE TO THE PATHOGENESIS OF MANY SKIN DISEASES, INCLUDING SKIN CANCER AND PSORIASIS. HOWEVER, WHILE THE EPIGENETIC REGULATION OF EPIDERMAL HOMEOSTASIS IS NOW BECOMING ACTIVE AREA OF RESEARCH, THE EPIGENETIC MECHANISMS CONTROLLING THE WOUND HEALING RESPONSE REMAIN RELATIVELY UNTOUCHED. RECENT ADVANCES: SUBSTANTIAL PROGRESS ACHIEVED WITHIN THE LAST TWO DECADES IN UNDERSTANDING EPIGENETIC MECHANISMS CONTROLLING GENE EXPRESSION ALLOWED DEFINING SEVERAL LEVELS, INCLUDING COVALENT DNA AND HISTONE MODIFICATIONS, ATP-DEPENDENT AND HIGHER-ORDER CHROMATIN CHROMATIN REMODELING, AS WELL AS NONCODING RNA- AND MICRORNA-DEPENDENT REGULATION. RESEARCH PERTAINED OVER THE LAST FEW YEARS SUGGESTS THAT EPIGENETIC REGULATORY MECHANISMS PLAY A PIVOTAL ROLE IN THE REGULATION OF SKIN REGENERATION AND CONTROL AN EXECUTION OF REPARATIVE GENE EXPRESSION PROGRAMS IN BOTH SKIN EPITHELIUM AND MESENCHYME. CRITICAL ISSUES: EPIGENETIC REGULATORS APPEAR TO BE INHERENTLY INVOLVED IN THE PROCESSES OF SKIN REPAIR, AND ARE ABLE TO DYNAMICALLY REGULATE KERATINOCYTE PROLIFERATION, DIFFERENTIATION, AND MIGRATION, TOGETHER WITH INFLUENCING DERMAL REGENERATION AND NEOANGIOGENESIS. THIS IS ACHIEVED THROUGH A SERIES OF COMPLEX REGULATORY MECHANISMS THAT ARE ABLE TO BOTH STIMULATE AND REPRESS GENE ACTIVATION TO TRANSIENTLY ALTER CELLULAR PHENOTYPE AND BEHAVIOR, AND INTERACT WITH GROWTH FACTOR ACTIVITY. FUTURE DIRECTIONS: UNDERSTANDING THE MOLECULAR BASIS OF EPIGENETIC REGULATION IS A PRIORITY AS IT REPRESENTS POTENTIAL THERAPEUTIC TARGETS FOR THE TREATMENT OF BOTH ACUTE AND CHRONIC SKIN CONDITIONS. FUTURE RESEARCH IS, THEREFORE, IMPERATIVE TO HELP DISTINGUISH EPIGENETIC MODULATING DRUGS THAT CAN BE USED TO IMPROVE WOUND HEALING. 2014 20 5805 37 STRATEGIES TO PREVENT AND REVERSE LIVER FIBROSIS IN HUMANS AND LABORATORY ANIMALS. LIVER FIBROSIS RESULTS FROM CHRONIC DAMAGE TO THE LIVER IN CONJUNCTION WITH VARIOUS PATHWAYS AND IS MEDIATED BY A COMPLEX MICROENVIRONMENT. BASED ON CLINICAL OBSERVATIONS, IT IS NOW EVIDENT THAT FIBROSIS IS A DYNAMIC, BIDIRECTIONAL PROCESS WITH AN INHERENT CAPACITY FOR RECOVERY AND REMODELING. THE MAJOR MECHANISMS INVOLVED IN LIVER FIBROSIS INCLUDE THE REPETITIVE INJURY OF HEPATOCYTES, THE ACTIVATION OF THE INFLAMMATORY RESPONSE AFTER INJURY STIMULATION, AND THE ACTIVATION AND PROLIFERATION OF HEPATIC STELLATE CELLS (HSCS), WHICH REPRESENTS THE MAJOR EXTRACELLULAR MATRIX (ECM)-PRODUCING CELLS, STIMULATED BY HEPATOCYTE INJURY AND INFLAMMATION. THE MICROENVIRONMENT IN THE LIVER IS SYNERGISTICALLY REGULATED ABNORMAL ECM DEPOSITION, SCAR FORMATION, ANGIOGENESIS, AND FIBROGENESIS. MOREOVER, RECENT STUDIES HAVE CLARIFIED NOVEL MECHANISM IN FIBROSIS SUCH AS EPIGENETIC REGULATION OF HSCS, THE LEPTIN AND PPARGAMMA PATHWAYS, THE COAGULATION SYSTEM, AND EVEN AUTOPHAGY. UNCOVERING THE MECHANISMS OF LIVER FIBROGENESIS PROVIDES A BASIS TO DEVELOP POTENTIAL THERAPIES TO REVERSE AND TREAT THE FIBROTIC RESPONSE, THEREBY IMPROVING THE OUTCOMES OF PATIENTS WITH CHRONIC LIVER DISEASE. ALTHOUGH BOTH SCIENTIFIC AND CLINICAL CHALLENGES REMAIN, EMERGING STUDIES ATTEMPT TO REVEAL THE IDEAL ANTI-FIBROTIC DRUG THAT COULD BE EASILY DELIVERED TO THE LIVER WITH HIGH SPECIFICITY AND LOW TOXICITY. THIS REVIEW HIGHLIGHTS THE MECHANISMS, INCLUDING NOVEL PATHWAYS UNDERLYING FIBROGENESIS THAT MAY BE TRANSLATED INTO PREVENTIVE AND TREATMENT STRATEGIES, REVIEWS BOTH CURRENT AND NOVEL AGENTS THAT TARGET SPECIFIC PATHWAYS OR MULTIPLE TARGETS, AND DISCUSSES NOVEL DRUG DELIVERY SYSTEMS SUCH AS NANOTECHNOLOGY THAT CAN BE APPLIED IN THE TREATMENT OF LIVER FIBROSIS. IN ADDITION, WE ALSO DISCUSS SOME CURRENT TREATMENT STRATEGIES THAT ARE BEING APPLIED IN ANIMAL MODELS AND IN CLINICAL TRIALS. 2015