1 4480 140 MOLECULAR PATHWAYS AND ROLE OF EPIGENETICS IN THE IDIOPATHIC PULMONARY FIBROSIS. IDIOPATHIC PULMONARY FIBROSIS (IPF) IS A FATAL LUNG DISEASE WITH UNKNOWN ETIOLOGICAL FACTORS THAT CAN PROGRESS TO OTHER DANGEROUS DISEASES LIKE LUNG CANCER. ENVIRONMENTAL AND GENETIC PREDISPOSITION ARE THE TWO MAJOR ETIOLOGICAL OR RISK FACTORS INVOLVED IN THE PATHOLOGY OF THE IPF. AMONG THE ENVIRONMENTAL RISK FACTORS, SMOKING IS ONE OF THE MAJOR CAUSES FOR THE DEVELOPMENT OF IPF. EPIGENETIC PATHWAYS LIKE NUCLEOSOMES REMODELING, DNA METHYLATION, HISTONE MODIFICATIONS AND MIRNA MEDIATED GENES PLAY A CRUCIAL ROLE IN DEVELOPMENT OF IPF. MUTATIONS IN THE GENES MAKE THE EPIGENETIC FACTORS AS IMPORTANT DRUG TARGETS IN IPF. TRANSCRIPTIONAL CHANGES DUE TO ENVIRONMENTAL FACTORS ARE ALSO INVOLVED IN THE PROGRESSION OF IPF. THE MUTATIONS IN HUMAN TELOMERASE REVERSE TRANSCRIPTASE (HTERT) HAVE SHOWN DECREASED LIFE EXPECTANCY IN IPF PATIENTS. THE TERT-GENE IS HIGHLY EXPRESSED IN CHRONIC SMOKERS AND MAKES THE ROLE OF EPIGENETICS EVIDENT. DRUG LIKE NINTEDANIB ACTS THROUGH VASCULAR ENDOTHELIAL GROWTH FACTOR RECEPTORS (VEGFR), WHILE DRUG PIRFENIDONE ACTS THROUGH TRANSFORMING GROWTH FACTOR (TGF), WHICH IS USEFUL IN IPF. GEFITINIB, A TYROSINE KINASE INHIBITOR OF EGFR, IS USEFUL AS AN ANTI-FIBROSIS AGENT IN PRECLINICAL MODELS. NEWER DRUGS SUCH AS CELGENE-CC90001 AND FIBROGEN-FG-3019 ARE CURRENTLY UNDER INVESTIGATIONS ACTS THROUGH THE MODULATING EPIGENETIC MECHANISMS. THUS, THE STUDY ON EPIGENETICS OPENS A WIDE WINDOW FOR THE DISCOVERY OF NEWER DRUGS. THIS STUDY PROVIDES AN ELEMENTARY ANALYSIS OF MULTIPLE REGULATORS OF EPIGENETICS AND THEIR ROLES ASSOCIATED WITH THE PATHOLOGY OF IPF. FURTHER, THIS REVIEW ALSO INCLUDES EPIGENETIC DRUGS UNDER DEVELOPMENT IN PRECLINICAL AND CLINICAL STAGES. 2022 2 5456 34 RESEARCH ADVANCES ON DNA METHYLATION IN IDIOPATHIC PULMONARY FIBROSIS. IDIOPATHIC PULMONARY FIBROSIS (IPF) IS A CHRONIC COMPLEX LUNG DISEASE WITH NO SPECIFIC TREATMENT AND POOR PROGNOSIS, CHARACTERIZED BY THE PULMONARY PROGRESSIVE FIBROSIS AND DYSFUNCTIONS THAT LEAD TO RESPIRATORY FAILURE. SEVERAL FACTORS MAY IMPACT THE PROGRESS OF IPF, INCLUDING AGE, CIGARETTE SMOKING, AND DUSTS, OF WHICH GENETIC AND EPIGENETIC FACTORS MAINLY CONTRIBUTE TO LUNG TISSUE FIBROSIS. DNA METHYLATION IS ONE OF EPIGENETIC PROCESSES THAT OCCUR IN MANY DISEASES AND REGULATE CHROMOSOMAL AND EXTRACHROMOSOMAL DNA FUNCTIONS IN RESPONSE TO ENVIRONMENTAL EXPOSURES. THE METHYLATION PLAYS PIVOTAL ROLES IN REGULATION OF GENE EXPRESSION TO FACILITATE THE FORMATION OF FIBROBLASTIC FOCI AND LUNG FIBROSIS. THIS CHAPTER WILL DESCRIBE ALTERATIONS AND EFFECTS OF THE DNA METHYLATION ON GENE EXPRESSION, THE POTENTIAL APPLICATION OF DNA METHYLATION AS A BIOMARKER, AND SIGNIFICANCE AS THERAPEUTIC TARGETS. THOSE UNDERSTANDING WILL PROVIDE US NEW INSIGHT INTO THE TREATMENT AND PROGNOSIS OF IPF. 2020 3 4038 41 MACROPHAGE IMPLICATION IN IPF: UPDATES ON IMMUNE, EPIGENETIC, AND METABOLIC PATHWAYS. IDIOPATHIC PULMONARY FIBROSIS (IPF) IS A LETHAL INTERSTITIAL LUNG DISEASE OF UNKNOWN ETIOLOGY WITH A POOR PROGNOSIS. IT IS A CHRONIC AND PROGRESSIVE DISEASE THAT HAS A DISTINCT RADIOLOGICAL AND PATHOLOGICAL PATTERN FROM COMMON INTERSTITIAL PNEUMONIA. THE USE OF IMMUNOSUPPRESSIVE MEDICATION WAS SHOWN TO BE COMPLETELY INEFFECTIVE IN CLINICAL TRIALS, RESULTING IN YEARS OF NEGLECT OF THE IMMUNE COMPONENT. HOWEVER, RECENT DEVELOPMENTS IN FUNDAMENTAL AND TRANSLATIONAL SCIENCE DEMONSTRATE THAT IMMUNE CELLS PLAY A SIGNIFICANT REGULATORY ROLE IN IPF, AND MACROPHAGES APPEAR TO BE AMONG THE MOST CRUCIAL. THESE HIGHLY PLASTIC CELLS GENERATE MULTIPLE GROWTH FACTORS AND MEDIATORS THAT HIGHLY AFFECT THE INITIATION AND PROGRESSION OF IPF. IN THIS REVIEW, WE WILL PROVIDE AN UPDATE ON THE ROLE OF MACROPHAGES IN IPF THROUGH A SYSTEMIC DISCUSSION OF VARIOUS REGULATORY MECHANISMS INVOLVING IMMUNE RECEPTORS, CYTOKINES, METABOLISM, AND EPIGENETICS. 2023 4 4450 49 MOLECULAR MECHANISMS AND CELLULAR CONTRIBUTION FROM LUNG FIBROSIS TO LUNG CANCER DEVELOPMENT. IDIOPATHIC PULMONARY FIBROSIS (IPF) IS A CHRONIC, PROGRESSIVE, FIBROSING INTERSTITIAL LUNG DISEASE (ILD) OF UNKNOWN AETIOLOGY, WITH A MEDIAN SURVIVAL OF 2-4 YEARS FROM THE TIME OF DIAGNOSIS. ALTHOUGH IPF HAS UNKNOWN AETIOLOGY BY DEFINITION, THERE HAVE BEEN IDENTIFIED SEVERAL RISKS FACTORS INCREASING THE PROBABILITY OF THE ONSET AND PROGRESSION OF THE DISEASE IN IPF PATIENTS SUCH AS CIGARETTE SMOKING AND ENVIRONMENTAL RISK FACTORS ASSOCIATED WITH DOMESTIC AND OCCUPATIONAL EXPOSURE. AMONG THEM, CIGARETTE SMOKING TOGETHER WITH CONCOMITANT EMPHYSEMA MIGHT PREDISPOSE IPF PATIENTS TO LUNG CANCER (LC), MOSTLY TO NON-SMALL CELL LUNG CANCER (NSCLC), INCREASING THE RISK OF LUNG CANCER DEVELOPMENT. TO THIS PURPOSE, IPF AND LC SHARE SEVERAL CELLULAR AND MOLECULAR PROCESSES DRIVING THE PROGRESSION OF BOTH PATHOLOGIES SUCH AS FIBROBLAST TRANSITION PROLIFERATION AND ACTIVATION, ENDOPLASMIC RETICULUM STRESS, OXIDATIVE STRESS, AND MANY GENETIC AND EPIGENETIC MARKERS THAT PREDISPOSE IPF PATIENTS TO LC DEVELOPMENT. NINTEDANIB, A TYROSINE-KINASE INHIBITOR, WAS FIRSTLY DEVELOPED AS AN ANTICANCER DRUG AND THEN RECOGNIZED AS AN ANTI-FIBROTIC AGENT BASED ON THE COMMON TARGET MOLECULAR PATHWAY. IN THIS REVIEW OUR AIM IS TO DESCRIBE THE UPDATED STUDIES ON COMMON CELLULAR AND MOLECULAR MECHANISMS BETWEEN IPF AND LUNG CANCER, KNOWLEDGE OF WHICH MIGHT HELP TO FIND NOVEL THERAPEUTIC TARGETS FOR THIS DISEASE COMBINATION. 2021 5 6223 37 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 6 4294 43 MICRORNA REGULATORY NETWORKS IN IDIOPATHIC PULMONARY FIBROSIS. IDIOPATHIC PULMONARY FIBROSIS (IPF) IS A CHRONIC, PROGRESSIVE, AND FATAL SCARRING LUNG DISEASE OF UNKNOWN ETIOLOGY, CHARACTERIZED BY CHANGES IN MICRORNA EXPRESSION. ACTIVATION OF TRANSFORMING GROWTH FACTOR (TGF-BETA) IS A KEY EVENT IN THE DEVELOPMENT OF IPF. RECENT REPORTS HAVE ALSO IDENTIFIED EPIGENETIC MODIFICATION AS AN IMPORTANT PLAYER IN THE PATHOGENESIS OF IPF. IN THIS REVIEW, WE SUMMARIZE THE MAIN RESULTS OF STUDIES THAT ADDRESS THE ROLE OF MICRORNAS IN IPF AND HIGHLIGHT THE SYNERGISTIC ACTIONS OF THESE MICRORNAS IN REGULATING TGF-BETA, THE PRIMARY FIBROGENIC MEDIATOR. WE OUTLINE EPIGENETIC REGULATION OF MICRORNAS BY METHYLATION. FUNCTIONAL STUDIES IDENTIFY MICRORNAS THAT ALTER PROLIFERATIVE AND MIGRATORY PROPERTIES OF FIBROBLASTS, AND INDUCE PHENOTYPIC CHANGES IN EPITHELIAL CELLS CONSISTENT WITH EPITHELIAL-MESENCHYMAL TRANSITION. THOUGH THESE STUDIES WERE PERFORMED IN ISOLATION, WE IDENTIFY MULTIPLE CO-OPERATIVE ACTIONS AFTER ASSEMBLING THE RESULTS INTO A NETWORK. CONSTRUCTION OF SUCH NETWORKS WILL HELP IDENTIFY DISEASE-PROPELLING HUBS THAT CAN BE TARGETED FOR THERAPEUTIC PURPOSES. 2015 7 5575 40 ROLE OF MICRORNAS IN SIGNALING PATHWAYS ASSOCIATED WITH THE PATHOGENESIS OF IDIOPATHIC PULMONARY FIBROSIS: A FOCUS ON EPITHELIAL-MESENCHYMAL TRANSITION. IDIOPATHIC PULMONARY FIBROSIS (IPF) IS A CHRONIC AND PROGRESSIVE DISEASE WITH HIGH MORTALITY AND UNCLEAR ETIOLOGY. PREVIOUS EVIDENCE SUPPORTS THAT THE ORIGIN OF THIS DISEASE IS ASSOCIATED WITH EPIGENETIC ALTERATIONS, AGE, AND ENVIRONMENTAL FACTORS. IPF INITIATES WITH CHRONIC EPITHELIAL LUNG INJURIES, FOLLOWED BY BASAL MEMBRANE DESTRUCTION, WHICH PROMOTES THE ACTIVATION OF MYOFIBROBLASTS AND EXCESSIVE SYNTHESIS OF EXTRACELLULAR MATRIX (ECM) PROTEINS, AS WELL AS EPITHELIAL-MESENCHYMAL TRANSITION (EMT). DUE TO MIRNAS' ROLE AS REGULATORS OF APOPTOSIS, PROLIFERATION, DIFFERENTIATION, AND CELL-CELL INTERACTION PROCESSES, SOME STUDIES HAVE INVOLVED MIRNAS IN THE BIOGENESIS AND PROGRESSION OF IPF. IN THIS CONTEXT, THE ANALYSIS AND DISCUSSION OF THE PROBABLE ASSOCIATION OF MIRNAS WITH THE SIGNALING PATHWAYS INVOLVED IN THE DEVELOPMENT OF IPF WOULD IMPROVE OUR KNOWLEDGE OF THE ASSOCIATED MOLECULAR MECHANISMS, THEREBY FACILITATING ITS EVALUATION AS A THERAPEUTIC TARGET FOR THIS SEVERE LUNG DISEASE. IN THIS WORK, THE MOST RECENT PUBLICATIONS EVALUATING THE ROLE OF MIRNAS AS REGULATORS OR ACTIVATORS OF SIGNAL PATHWAYS ASSOCIATED WITH THE PATHOGENESIS OF IPF WERE ANALYZED. THE SEARCH IN PUBMED WAS MADE USING THE FOLLOWING TERMS: "MIRNAS AND IDIOPATHIC PULMONARY FIBROSIS (IPF)"; "MIRNAS AND IPF AND SIGNALING PATHWAYS (SP)"; AND "MIRNAS AND IPF AND SP AND IPF PATHOGENESIS". ADDITIONALLY, WE FOCUS MAINLY ON THOSE WORKS WHERE THE SIGNALING PATHWAYS INVOLVED WITH EMT, FIBROBLAST DIFFERENTIATION, AND SYNTHESIS OF ECM COMPONENTS WERE ASSESSED. FINALLY, THE IMPORTANCE AND SIGNIFICANCE OF MIRNAS AS POTENTIAL THERAPEUTIC OR DIAGNOSTIC TOOLS FOR THE TREATMENT OF IPF ARE DISCUSSED. 2022 8 1113 35 COMMON PATHWAYS IN IDIOPATHIC PULMONARY FIBROSIS AND CANCER. IDIOPATHIC PULMONARY FIBROSIS (IPF) IS MARKED BY A VERY DISAPPOINTING SURVIVAL RATE AND STILL REPRESENTS A CLINICAL DILEMMA. ACCORDING TO THE CURRENT PATHOGENIC HYPOTHESIS, CHRONIC DAMAGE OF THE ALVEOLAR EPITHELIUM IS FOLLOWED BY ABNORMAL TISSUE REPAIR AND IMPAIRMENT OF THE ALVEOLAR STRUCTURE. THIS PROCESS IS DRIVEN BY PATHOGENIC EVENTS VERY SIMILAR TO CANCER, INCLUDING EPIGENETIC AND GENETIC CHANGES, ALTERED RESPONSE TO REGULATORY SIGNALS, ABNORMAL EXPRESSION OF MICRORNAS AND ACTIVATION OF SPECIFIC SIGNALLING PATHWAYS. IPF ALSO RESEMBLES CANCER WITH REGARD TO ITS POOR RESPONSE TO MEDICAL TREATMENT AND PROGNOSIS, WHICH IS VERY OFTEN WORSE THAN MANY CANCERS. WE HAVE HYPOTHESISED THAT IPF MIGHT BE ASSIMILATED TO A NEOPROLIFERATIVE DISORDER OF THE LUNG. VIEWING IPF AS A CANCER-LIKE DISEASE MAY SATISFY THE NEED FOR A BETTER UNDERSTANDING OF THE PATHOGENESIS OF IPF BY EXPLOITING THE LARGE AMOUNT OF KNOWLEDGE THAT CANCER BIOLOGY EVOKES. THE RECOGNITION OF COMMON PATHOGENIC PATHWAYS BETWEEN THE TWO DISEASES MAY STIMULATE NEW CLINICAL TRIALS WITH CANCER DRUGS, DIFFERENT DRUG COMBINATIONS AND DIFFERENT LINES OF DRUGS, AS ALREADY EXPERIMENTED IN ONCOLOGY. MOREOVER, THE CONCEPT OF IPF AS A CANCER-LIKE DISORDER MAY IMPROVE THE ATTENTION GIVEN TO THIS DREADFUL DISEASE ON A PUBLIC, POLITICAL AND HEALTHCARE LEVEL. 2013 9 6212 34 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 10 2527 31 EPIGENETICS APPROACHES TOWARD PRECISION MEDICINE FOR IDIOPATHIC PULMONARY FIBROSIS: FOCUS ON DNA METHYLATION. GENETIC INFORMATION IS NOT TRANSMITTED SOLELY BY DNA BUT BY THE EPIGENETICS PROCESS. EPIGENETICS DESCRIBES MOLECULAR MISSING LINK PATHWAYS THAT COULD BRIDGE THE GAP BETWEEN THE GENETIC BACKGROUND AND ENVIRONMENTAL RISK FACTORS THAT CONTRIBUTE TO THE PATHOGENESIS OF PULMONARY FIBROSIS. SPECIFIC EPIGENETIC PATTERNS, ESPECIALLY DNA METHYLATION, HISTONE MODIFICATIONS, LONG NON-CODING, AND MICRORNA (MIRNAS), AFFECT THE ENDOPHENOTYPES UNDERLYING THE DEVELOPMENT OF IDIOPATHIC PULMONARY FIBROSIS (IPF). AMONG ALL THE EPIGENETIC MARKS, DNA METHYLATION MODIFICATIONS HAVE BEEN THE MOST WIDELY STUDIED IN IPF. THIS REVIEW SUMMARIZES THE CURRENT KNOWLEDGE CONCERNING DNA METHYLATION CHANGES IN PULMONARY FIBROSIS AND DEMONSTRATES A PROMISING NOVEL EPIGENETICS-BASED PRECISION MEDICINE. 2023 11 5769 37 SPECIFIC EPIGENETIC REGULATORS SERVE AS POTENTIAL THERAPEUTIC TARGETS IN IDIOPATHIC PULMONARY FIBROSIS. IDIOPATHIC PULMONARY FIBROSIS (IPF), A DISORDER OBSERVED MOSTLY IN OLDER HUMAN BEINGS, IS CHARACTERISED BY CHRONIC AND PROGRESSIVE LUNG SCARRING LEADING TO AN IRREVERSIBLE DECLINE IN LUNG FUNCTION. THIS HEALTH CONDITION HAS A DISMAL PROGNOSIS AND THE CURRENTLY AVAILABLE DRUGS ONLY DELAY BUT FAIL TO REVERSE THE PROGRESSION OF LUNG DAMAGE. CONSEQUENTLY, IT BECOMES IMPERATIVE TO DISCOVER IMPROVED THERAPEUTIC COMPOUNDS AND THEIR CELLULAR TARGETS TO CURE IPF. IN THIS REGARD, A NUMBER OF RECENT STUDIES HAVE TARGETED THE EPIGENETIC REGULATION BY HISTONE DEACETYLASES (HDACS) TO DEVELOP AND CATEGORISE ANTIFIBROTIC DRUGS FOR LUNGS. THEREFORE, THIS REVIEW FOCUSES ON HOW ABERRANT EXPRESSION OR ACTIVITY OF CLASSES I, II AND III HDACS ALTER TGF-BETA SIGNALLING TO PROMOTE EVENTS SUCH AS EPITHELIAL-MESENCHYMAL TRANSITION, DIFFERENTIATION OF ACTIVATED FIBROBLASTS INTO MYOFIBROBLASTS, AND EXCESS DEPOSITION OF THE EXTRACELLULAR MATRIX TO PROPEL LUNG FIBROSIS. FURTHER, THIS STUDY DESCRIBES HOW CERTAIN CHEMICAL COMPOUNDS OR DIETARY CHANGES MODULATE DYSREGULATED HDACS TO ATTENUATE FIVE FAULTY TGF-BETA-DEPENDENT PROFIBROTIC PROCESSES, BOTH IN ANIMAL MODELS AND CELL LINES REPLICATING IPF, THEREBY IDENTIFYING PROMISING MEANS TO TREAT THIS LUNG DISORDER. 2022 12 2169 43 EPIGENETIC MECHANISMS IN PARENCHYMAL LUNG DISEASES: BYSTANDERS OR THERAPEUTIC TARGETS? EPIGENETIC RESPONSES DUE TO ENVIRONMENTAL CHANGES ALTER CHROMATIN STRUCTURE, WHICH IN TURN MODIFIES THE PHENOTYPE, GENE EXPRESSION PROFILE, AND ACTIVITY OF EACH CELL TYPE THAT HAS A ROLE IN THE PATHOPHYSIOLOGY OF A DISEASE. PULMONARY DISEASES ARE ONE OF THE MAJOR CAUSES OF DEATH IN THE WORLD, INCLUDING LUNG CANCER, IDIOPATHIC PULMONARY FIBROSIS (IPF), CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD), PULMONARY HYPERTENSION (PH), LUNG TUBERCULOSIS, PULMONARY EMBOLISM, AND ASTHMA. SEVERAL LINES OF EVIDENCE INDICATE THAT EPIGENETIC MODIFICATIONS MAY BE ONE OF THE MAIN FACTORS TO EXPLAIN THE INCREASING INCIDENCE AND PREVALENCE OF LUNG DISEASES INCLUDING IPF AND COPD. INTERESTINGLY, ISOLATED FIBROBLASTS AND SMOOTH MUSCLE CELLS FROM PATIENTS WITH PULMONARY DISEASES SUCH AS IPF AND PH THAT WERE CULTURED EX VIVO MAINTAINED THE DISEASE PHENOTYPE. THE CELLS OFTEN SHOW A HYPER-PROLIFERATIVE, APOPTOSIS-RESISTANT PHENOTYPE WITH INCREASED EXPRESSION OF EXTRACELLULAR MATRIX (ECM) AND ACTIVATED FOCAL ADHESIONS SUGGESTING THE PRESENCE OF AN EPIGENETICALLY IMPRINTED PHENOTYPE. MOREOVER, MANY ABNORMALITIES OBSERVED IN MOLECULAR PROCESSES IN IPF PATIENTS ARE SHOWN TO BE EPIGENETICALLY REGULATED, SUCH AS INNATE IMMUNITY, CELLULAR SENESCENCE, AND APOPTOTIC CELL DEATH. DNA METHYLATION, HISTONE MODIFICATION, AND MICRORNA REGULATION CONSTITUTE THE MOST COMMON EPIGENETIC MODIFICATION MECHANISMS. 2022 13 1597 43 DNA METHYLATION REGULATED GENE EXPRESSION IN ORGAN FIBROSIS. DNA METHYLATION IS A MAJOR EPIGENETIC MECHANISM TO REGULATE GENE EXPRESSION. EPIGENETIC REGULATION, INCLUDING DNA METHYLATION, HISTONE MODIFICATIONS AND RNA INTERFERENCE, RESULTS IN HERITABLE CHANGES IN GENE EXPRESSION INDEPENDENT OF ALTERATIONS IN DNA SEQUENCE. EPIGENETIC REGULATION OFTEN OCCURS IN RESPONSE TO AGING AND ENVIRONMENT STIMULI, INCLUDING EXPOSURES AND DIET. STUDIES HAVE SHOWN THAT DNA METHYLATION IS CRITICAL IN THE PATHOGENESIS OF FIBROSIS INVOLVING MULTIPLE ORGAN SYSTEMS, CONTRIBUTING TO SIGNIFICANT MORBIDITY AND MORTALITY. ABERRANT DNA METHYLATION CAN SILENCE OR ACTIVATE GENE EXPRESSION PATTERNS THAT DRIVE THE FIBROSIS PROCESS. FIBROSIS IS A PATHOLOGICAL WOUND HEALING PROCESS IN RESPONSE TO CHRONIC INJURY. IT IS CHARACTERIZED BY EXCESSIVE EXTRACELLULAR MATRIX PRODUCTION AND ACCUMULATION, WHICH EVENTUALLY AFFECTS ORGAN ARCHITECTURE AND RESULTS IN ORGAN FAILURE. FIBROSIS CAN AFFECT A WIDE RANGE OF ORGANS, INCLUDING THE HEART AND LUNGS, AND HAVE LIMITED THERAPEUTIC OPTIONS. DNA METHYLATION, LIKE OTHER EPIGENETIC PROCESS, IS REVERSIBLE, THEREFORE REGARDED AS ATTRACTIVE THERAPEUTIC INTERVENTIONS. ALTHOUGH EPIGENETIC MECHANISMS ARE HIGHLY INTERACTIVE AND OFTEN REINFORCING, THIS REVIEW DISCUSSES DNA METHYLATION-DEPENDENT MECHANISMS IN THE PATHOGENESIS OF ORGAN FIBROSIS, WITH FOCUS ON CARDIAC AND PULMONARY FIBROSIS. WE DISCUSS SPECIFIC PRO- AND ANTI-FIBROTIC GENES AND PATHWAYS REGULATED BY DNA METHYLATION IN ORGAN FIBROSIS; WE FURTHER HIGHLIGHT THE POTENTIAL BENEFITS AND SIDE-EFFECTS OF EPIGENETIC THERAPIES IN FIBROTIC DISORDERS. 2017 14 610 39 BEYOND THE GENOME: EPIGENETIC MECHANISMS IN LUNG REMODELING. THE LUNG DEVELOPS FROM A VERY SIMPLE OUTPOUCHING OF THE FOREGUT INTO A HIGHLY COMPLEX, FINELY STRUCTURED ORGAN WITH MULTIPLE SPECIALIZED CELL TYPES THAT ARE REQUIRED FOR ITS NORMAL PHYSIOLOGICAL FUNCTION. DURING BOTH THE DEVELOPMENT OF THE LUNG AND ITS REMODELING IN THE CONTEXT OF DISEASE OR RESPONSE TO INJURY, GENE EXPRESSION MUST BE ACTIVATED AND SILENCED IN A COORDINATED MANNER TO ACHIEVE THE TREMENDOUS PHENOTYPIC HETEROGENEITY OF CELL TYPES REQUIRED FOR HOMEOSTASIS AND PATHOGENESIS. EPIGENETIC MECHANISMS, CONSISTING OF DNA BASE MODIFICATIONS SUCH AS METHYLATION, ALTERATION OF HISTONES RESULTING IN CHROMATIN MODIFICATION, AND THE ACTION OF NONCODING RNA, CONTROL THE REGULATION OF INFORMATION "BEYOND THE GENOME" REQUIRED FOR BOTH LUNG MODELING AND REMODELING. EPIGENETIC REGULATION IS SUBJECT TO MODIFICATION BY ENVIRONMENTAL STIMULI, SUCH AS OXIDATIVE STRESS, INFECTION, AND AGING, AND IS THUS CRITICALLY IMPORTANT IN CHRONIC REMODELING DISORDERS SUCH AS IDIOPATHIC PULMONARY FIBROSIS (IPF), CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD), BRONCHOPULMONARY DYSPLASIA (BPD), AND PULMONARY HYPERTENSION (PH). TECHNOLOGICAL ADVANCES HAVE MADE IT POSSIBLE TO EVALUATE GENOME-WIDE EPIGENETIC CHANGES (EPIGENOMICS) IN DISEASES OF LUNG REMODELING, CLARIFYING EXISTING PATHOPHYSIOLOGICAL PARADIGMS AND UNCOVERING NOVEL MECHANISMS OF DISEASE. MANY OF THESE REPRESENT NEW THERAPEUTIC TARGETS. ADVANCES IN EPIGENOMIC TECHNOLOGY WILL ACCELERATE OUR UNDERSTANDING OF LUNG DEVELOPMENT AND REMODELING, AND LEAD TO NOVEL TREATMENTS FOR CHRONIC LUNG DISEASES. 2014 15 5484 36 REVEALING THE PATHOGENIC AND AGING-RELATED MECHANISMS OF THE ENIGMATIC IDIOPATHIC PULMONARY FIBROSIS. AN INTEGRAL MODEL. A GROWING BODY OF EVIDENCE INDICATES THAT ABERRANT ACTIVATION OF ALVEOLAR EPITHELIAL CELLS AND FIBROBLASTS IN AN AGING LUNG PLAYS A CRITICAL ROLE IN THE PATHOGENESIS OF IDIOPATHIC PULMONARY FIBROSIS (IPF). HOWEVER, THE BIOPATHOLOGICAL PROCESSES LINKING AGING WITH IPF AND THE MECHANISMS RESPONSIBLE FOR THE ABNORMAL ACTIVATION OF EPITHELIAL CELLS AND FIBROBLASTS HAVE NOT BEEN ELUCIDATED. MANY OF THE HALLMARKS OF AGING (E.G., GENOMIC INSTABILITY, TELOMERE ATTRITION, EPIGENETIC ALTERATIONS, MITOCHONDRIAL DYSFUNCTION, AND CELLULAR SENESCENCE) HAVE BEEN PROPOSED AS ESSENTIAL MECHANISMS FOR THE DEVELOPMENT OF IPF; HOWEVER, THESE DISTURBANCES ARE NOT RESTRICTED TO IPF AND ALSO OCCUR IN OTHER AGING-RELATED LUNG DISORDERS, PRIMARILY CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). THEREFORE, AN UNANSWERED QUESTION IS WHY A CURRENT/FORMER SMOKER OF ABOUT 60 YEARS OF AGE WITH SHORTER TELOMERES, ALVEOLAR EPITHELIAL SENESCENCE, EXCESSIVE OXIDATIVE STRESS, AND MITOCHONDRIAL DYSFUNCTION DEVELOPS IPF AND NOT COPD; IN OTHER WORDS, WHAT MAKES OLD LUNGS SPECIFICALLY SUSCEPTIBLE TO DEVELOP IPF? IN THIS PERSPECTIVE, WE PROPOSE AN INTEGRAL MODEL IN WHICH THE COMBINATION OF SOME GENE VARIANTS AND/OR GENE EXPRESSION IN THE AGING LUNG RESULTS IN THE LOSS OF EPITHELIAL INTEGRITY AND CONSEQUENTLY IN THE FAILURE OF THE ALVEOLI TO CORRECTLY RESPOND TO INJURY AND TO FACE THE STRESS ASSOCIATED WITH MECHANICAL STRETCH. AFTERWARD, A DISTINCTIVE EPIGENETIC "REPROGRAMMING" THAT AFFECTS BOTH EPITHELIAL CELLS AND FIBROBLASTS PROVOKES, AMONG OTHERS, THE RECAPITULATION OF DEVELOPMENTAL PATHWAYS AND THE ABERRANT ACTIVATION AND MISCOMMUNICATION BETWEEN BOTH CELL TYPES, RESULTING IN THE EXAGGERATED PRODUCTION AND ACCUMULATION OF EXTRACELLULAR MATRIX AND THE SUBSEQUENT DESTRUCTION OF THE LUNG ARCHITECTURE. 2014 16 2540 35 EPIGENETICS IN IDIOPATHIC PULMONARY FIBROSIS. IDIOPATHIC PULMONARY FIBROSIS (IPF) IS A LETHAL CHRONIC LUNG DISORDER WITH NO EFFECTIVE TREATMENT AND A PROGNOSIS WORSE THAN THAT OF LUNG CANCER. DESPITE EXTENSIVE RESEARCH EFFORTS, ITS ETIOLOGY AND PATHOGENESIS STILL REMAIN LARGELY UNKNOWN. CURRENT EXPERIMENTAL EVIDENCE HAS SHIFTED THE DISEASE PARADIGM FROM CHRONIC INFLAMMATION TOWARDS THE PREMISE OF ABNORMAL EPITHELIAL WOUND REPAIR IN RESPONSE TO REPEATED EPIGENETIC INJURIOUS STIMULI IN GENETICALLY PREDISPOSED INDIVIDUALS. EPIGENETICS IS DEFINED AS THE STUDY OF HERITABLE CHANGES IN GENE FUNCTION BY FACTORS OTHER THAN AN INDIVIDUAL'S DNA SEQUENCE, PROVIDING VALUABLE INFORMATION REGARDING ADAPTION OF GENES TO ENVIRONMENTAL CHANGES. ALTHOUGH CANCER IS THE MOST STUDIED DISEASE WITH RELEVANCE TO EPIGENETIC MODIFICATIONS, RECENT DATA SUPPORT THE IDEA THAT EPIGENOMIC ALTERATIONS MAY LEAD TO VARIABLE DISEASE PHENOTYPES, INCLUDING FIBROPROLIFERATIVE LUNG DISORDERS SUCH AS IPF. THIS REVIEW ARTICLE SUMMARIZES THE LATEST EXPERIMENTAL AND TRANSLATIONAL EPIGENETIC STUDIES IN THE RESEARCH FIELD OF CHRONIC LUNG DISORDERS, MAINLY FOCUSING ON IPF, HIGHLIGHTS CURRENT METHODOLOGY LIMITATIONS, AND UNDERLINES FUTURE DIRECTIONS AND PERSPECTIVES. 2015 17 6199 42 THE IMPORTANCE OF EPIGENETICS IN THE DEVELOPMENT OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE. IT IS GENERALLY ACCEPTED THAT GENETIC PREDISPOSITION PLAYS A ROLE IN COPD DEVELOPMENT IN SUSCEPTIBLE INDIVIDUALS. THEREFORE, MANY CANDIDATE GENES THAT COULD BE LINKED TO THE DEVELOPMENT OF DISEASE HAVE BEEN EXAMINED IN COPD. HOWEVER, INCONSISTENT RESULTS IN DIFFERENT STUDY POPULATIONS OFTEN LIMIT THIS APPROACH, SUGGESTING THAT NOT ONLY GENETICS, BUT ALSO OTHER FACTORS, MAY BE CONTRIBUTED TO THE SUSCEPTIBILITY TO COPD. EPIGENETIC MECHANISMS CAN AFFECT THE TRANSCRIPTIONAL ACTIVITY OF SPECIFIC GENES, AT DIFFERENT POINTS IN TIME, AND IN DIFFERENT ORGANS. MOREOVER, THESE MECHANISMS CAN HAVE AN EFFECT ON PEOPLE'S HEALTH. RECENTLY, THERE IS EMERGING EVIDENCE SUPPORTING A ROLE OF EPIGENETICS FOR THE REGULATION OF INFLAMMATORY GENES IN DISEASES SUCH AS ASTHMA AND COPD. MOREOVER, RECENT STUDIES SUGGEST THAT THE CURRENTLY USED TREATMENTS INCLUDING CORTICOSTEROIDS MAY WORK THROUGH EPIGENETIC MECHANISMS. EPIGENETIC REGULATION CAN BE REPROGRAMMED, POTENTIALLY AFFECTING THE RISK, AETIOLOGY AND TREATMENT OF VARIOUS DISEASE STATES. THE EPIGENETICALLY INFLUENCED PHENOTYPE COULD BE REVERSED WITH DEMETHYLATING OR DEACETYLATING AGENTS, CONSISTENT WITH EPIGENETIC PLASTICITY. THE POSTNATAL REVERSIBILITY OF THESE METHYLATION OR ACETYLATION EVENTS MAY THEREFORE PROVIDE GOOD OPPORTUNITIES FOR INTERVENTION. THE RECOGNITION OF THE ROLE OF GENETIC AND EPIGENETIC MECHANISMS IN THE DEVELOPMENT OF COPD MAY IDENTIFY NOVEL TARGETS THAT HATCH NEW THERAPIES FOR PATIENTS WITH COPD. 2011 18 2933 42 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 19 2341 37 EPIGENETIC REGULATION OF LIVER FIBROSIS. FIBROSIS IS A COMMON AND IMPORTANT PATHOLOGY ASSOCIATED WITH PROGRESSIVE CHRONIC LIVER DISEASES AND UNDERLIES THE DEVELOPMENT OF CIRRHOSIS AND HEPATOCELLULAR CARCINOMA. RESEARCH INTO THE MOLECULAR REGULATION OF FIBROSIS HAS DISCOVERED THAT IT IS UNDER THE CONTROL OF A NUMBER OF EPIGENETIC MECHANISMS INCLUDING DNA METHYLATION, HISTONE MODIFICATIONS AND THE ACTIVITIES OF NON-CODING RNAS. A DEEPER UNDERSTANDING OF HOW EPIGENETIC REGULATORS SUCH AS DNA METHYLTRANSERASES, METHYL-DNA BINDING PROTEINS, HISTONE MODIFYING ENZYMES AND REGULATORY RNA MOLECULES IMPACT ON THE FIBROGENIC PROCESS IS EXPECTED TO RESULT IN NEW BIOMARKERS FOR DISEASE PROGRESSION AS WELL AS NOVEL THERAPEUTIC TARGETS. THE AIM OF THIS MINI-REVIEW IS TO BRIEFLY INTRODUCE THE READER TO THE MAJOR EPIGENETIC REGULATORS SO FAR IDENTIFIED AS BEING IMPLICATED IN FIBROSIS. 2015 20 2283 31 EPIGENETIC REGULATION IN FIBROSIS PROGRESS. FIBROSIS, A COMMON PROCESS OF CHRONIC INFLAMMATORY DISEASES, IS DEFINED AS A REPAIR RESPONSE DISORDER WHEN ORGANS UNDERGO CONTINUOUS DAMAGE, ULTIMATELY LEADING TO SCAR FORMATION AND FUNCTIONAL FAILURE. AROUND THE WORLD, FIBROTIC DISEASES CAUSE HIGH MORTALITY, UNFORTUNATELY, WITH LIMITED TREATMENT MEANS IN CLINICAL PRACTICE. WITH THE DEVELOPMENT AND APPLICATION OF DEEP SEQUENCING TECHNOLOGY, COMPREHENSIVELY EXPLORING THE EPIGENETIC MECHANISM IN FIBROSIS HAS BEEN ALLOWED. EXTENSIVE REMODELING OF EPIGENETICS CONTROLLING VARIOUS CELLS PHENOTYPE AND MOLECULAR MECHANISMS INVOLVED IN FIBROGENESIS WAS SUBSEQUENTLY VERIFIED. IN THIS REVIEW, WE SUMMARIZE THE REGULATORY MECHANISMS OF DNA METHYLATION, HISTONE MODIFICATION, NONCODING RNAS (NCRNAS) AND N6-METHYLADENOSINE (M6A) MODIFICATION IN ORGAN FIBROSIS, FOCUSING ON HEART, LIVER, LUNG AND KIDNEY. ADDITIONALLY, WE EMPHASIZE THE DIVERSITY OF EPIGENETICS IN THE CELLULAR AND MOLECULAR MECHANISMS RELATED TO FIBROSIS. FINALLY, THE POTENTIAL AND PROSPECT OF TARGETED THERAPY FOR FIBROSIS BASED ON EPIGENETIC IS DISCUSSED. 2021