1 5031 131 PERSPECTIVES ON THE ETIOLOGY OF CHRONIC RHINOSINUSITIS: AN IMMUNE BARRIER HYPOTHESIS. BACKGROUND: CHRONIC RHINOSINUSITIS (CRS) HAS BEEN DEFINED AS PERSISTENT SYMPTOMATIC INFLAMMATION OF THE NASAL AND SINUS MUCOSA RESULTING FROM THE INTERACTION OF MULTIPLE HOST AND ENVIRONMENTAL FACTORS. RECENT STUDIES HAVE IMPLICATED ALTERNARIA FUNGI OR TOXIGENIC STAPHYLOCOCCUS AUREUS AS CRITICAL AGENTS IN CRS PATHOGENESIS. THE EMPHASIS ON ENVIRONMENTAL AGENTS IN CRS ETIOLOGY HAS FOCUSED INTEREST TOWARD ELIMINATION OF THOSE AGENTS AS THE PRIME MECHANISM OF THERAPY. THIS VIEWPOINT IS IN MARKED CONTRAST TO THE CURRENT PERSPECTIVE ON SOME OTHER CHRONIC INFLAMMATORY EPITHELIAL DISORDERS THAT AFFLICT THE SKIN, LUNGS, AND GUT, WHEREIN HOST FACTORS ARE BELIEVED TO PREDISPOSE TO DISEASE EXPRESSION IN THE PRESENCE OF UBIQUITOUS ENVIRONMENTAL AGENTS. METHODS: THE CURRENT REVIEW EVALUATES CRS ETIOLOGY FROM THIS PERSPECTIVE AND CONSIDERS THAT CRS DEVELOPS, IN PART, AS AN OUTCOME OF A DYSFUNCTIONAL HOST RESPONSE. SPECIFICALLY, EVIDENCE FROM OUR LABORATORY AND OTHERS WILL BE REVIEWED INDICATING THAT CRS IS ASSOCIATED WITH A FAILURE OF THE MECHANICAL AND IMMUNOLOGIC BARRIERS ACROSS THE NASAL MUCOSA. THE HYPOTHESIS WOULD FURTHER PROPOSE THAT GENETIC AND EPIGENETIC VARIATION PREDISPOSES SUSCEPTIBLE INDIVIDUALS TO BARRIER FAILURE IN THE PRESENCE OF ENVIRONMENTAL STRESS LEADING TO CRS. RESULTS: FROM THIS UNIFYING PERSPECTIVE, BACTERIA AND FUNGI ARE SEEN AS DISEASE MODIFIERS RATHER THAN PRIMARY ETIOLOGIC AGENTS. CONCLUSION: THE GOAL IS TO PLACE CONCEPTS OF CRS PATHOPHYSIOLOGY IN A FRAMEWORK CONSISTENT WITH A CURRENT UNDERSTANDING OF CHRONIC INFLAMMATION IN GENERAL AND EPITHELIAL DISEASE IN PARTICULAR. 2008 2 2217 29 EPIGENETIC MODIFICATIONS IN CHRONIC RHINOSINUSITIS WITH AND WITHOUT NASAL POLYPS. CHRONIC RHINOSINUSITIS (CRS) HAS BROUGHT A HUGE SOCIOECONOMIC BURDEN. HOWEVER, ITS MECHANISM IS STILL ELUSIVE, WHICH MAY INVOLVE GENETIC, ENVIRONMENTAL AND SOME OTHER FACTORS. EPIGENETIC ANALYSES HAVE BEEN CONDUCTED TO EXPLORE THE MECHANISMS UNDERLYING CRS. HERE, WE REVIEWED THE FRUITS IN THE EPIGENETIC STUDIES ON DNA METHYLATION, HISTONE MODIFICATION, AND NON-CODING RNA REGULATION. WE CONCLUDED THAT THE EPIGENETIC RESEARCH ON CRS HAS MADE GREAT BREAKTHROUGHS, ESPECIALLY IN THE PAST 5 YEARS AND THE FIELD OF MICRORNAS. "EPIGENETIC THERAPIES" ARE EXPECTED TO BE DESIGNED TO TREAT CRS IN THE FUTURE. 2022 3 6288 45 THE POTENTIAL ROLE OF EPIGENETIC MODIFICATIONS ON DIFFERENT FACETS IN THE PERIODONTAL PATHOGENESIS. PERIODONTITIS IS A CHRONIC INFLAMMATORY DISEASE THAT AFFECTS THE SUPPORTING STRUCTURES OF TEETH. IN THE LITERATURE, THE ASSOCIATION BETWEEN THE PATHOGENICITY OF BACTERIA AND ENVIRONMENTAL FACTORS IN THIS REGARD HAVE BEEN EXTENSIVELY EXAMINED. IN THE PRESENT STUDY, WE WILL SHED LIGHT ON THE POTENTIAL ROLE THAT EPIGENETIC CHANGE CAN PLAY ON DIFFERENT FACETS OF ITS PROCESS, MORE PARTICULARLY THE MODIFICATIONS CONCERNING THE GENES INVOLVED IN INFLAMMATION, DEFENSE, AND IMMUNE SYSTEMS. SINCE THE 1960S, THE ROLE OF GENETIC VARIANTS IN THE ONSET AND SEVERITY OF PERIODONTAL DISEASE HAS BEEN WIDELY DEMONSTRATED. THESE MAKE SOME PEOPLE MORE SUSCEPTIBLE TO DEVELOPING IT THAN OTHERS. IT HAS BEEN DOCUMENTED THAT THE WIDE VARIATION IN ITS FREQUENCY FOR VARIOUS RACIAL AND ETHNIC POPULATIONS IS DUE PRIMARILY TO THE COMPLEX INTERPLAY AMONG GENETIC FACTORS WITH THOSE AFFECTING THE ENVIRONMENT AND THE DEMOGRAPHY. IN MOLECULAR BIOLOGY, EPIGENETIC MODIFICATIONS ARE DEFINED AS ANY CHANGE IN THE PROMOTER FOR THE CPG ISLANDS, IN THE STRUCTURE OF THE HISTONE PROTEIN, AS WELL AS POST-TRANSLATIONAL REGULATION BY MICRORNAS (MIRNAS), BEING KNOWN TO CONTRIBUTE TO THE ALTERATION IN GENE EXPRESSION FOR COMPLEX MULTIFACTORIAL DISEASES SUCH AS PERIODONTITIS. THE KEY ROLE OF EPIGENETIC MODIFICATION IS TO UNDERSTAND THE MECHANISM INVOLVED IN THE GENE-ENVIRONMENT INTERACTION, AND THE DEVELOPMENT OF PERIODONTITIS IS NOW THE SUBJECT OF MORE AND MORE STUDIES THAT ATTEMPT TO IDENTIFY WHICH FACTORS ARE STIMULATING IT, BUT ALSO AFFECT THE REDUCED RESPONSE TO THERAPY. 2023 4 6199 35 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 5 1606 34 DNA METHYLATION, BACTERIA AND AIRWAY INFLAMMATION: LATEST INSIGHTS. PURPOSE OF REVIEW: DNA METHYLATION IS AN EPIGENETIC MECHANISM THAT HAS BEEN IMPLICATED IN THE PATHOGENESIS OF CHRONIC INFLAMMATORY DISEASES BY REGULATING DIFFERENTIATION, PROLIFERATION, APOPTOSIS, AND ACTIVATION OF IMMUNE CELLS. CHANGES IN THE METHYLATION STATUS OF RELEVANT GENES HAVE BEEN LINKED TO THE ORIGIN, PERPETUATION, AND SEVERITY OF AIRWAY DISEASES. THE DNA METHYLATION PROFILE CAN BE ALSO MODIFIED BY THE ACTION OF VIRAL AND BACTERIAL COLONIZATION. BACTERIA AND SPECIALLY STAPHYLOCOCCUS AUREUS TOXINS ARE RECOGNIZED INFLAMMATORY AMPLIFYING FACTORS IN BOTH LOWER AND UPPER AIRWAY CHRONIC DISEASES. THIS REVIEW SUMMARIZES THE EXISTENT KNOWLEDGE ABOUT THE ROLE OF DNA METHYLATION CHANGES IN CHRONIC AIRWAY DISEASES AND THE CONTRIBUTION OF BACTERIAL INFECTION ON THIS EVENT. RECENT FINDINGS: IT HAS BEEN DEMONSTRATED THAT CHANGES IN DNA METHYLATION, EITHER INTRINSIC OR INDUCED BY ALLERGEN OR INFECTION, MAY BE LINKED TO THE PATHOGENESIS OF ASTHMA AND ALLERGY. THESE CHANGES IN METHYLATION MAY SUPPRESS THE PRODUCTION OF ANTI-INFLAMMATORY MEDIATORS AND INCREASE THE SURVIVAL AND ACTIVATION OF PRO-INFLAMMATORY CELLS, AS WELL AS MODIFY THE IMMUNE RESPONSE IN RESPONSE TO BACTERIAL INFECTION, INCREASING THEIR SURVIVAL AND PATHOGENICITY WITHIN THE INFECTED ORGANISM. SUMMARY: UNDERSTANDING THE INTRINSIC EPIGENETIC MECHANISMS, AS WELL AS THE EFFECT OF ENVIRONMENT -FOR EXAMPLE, BACTERIAL INFECTION IN THE PATHOGENESIS OF AIRWAYS DISEASES - WILL GREATLY IMPROVE THE MANAGEMENT AND THE DIAGNOSIS OF THESE DISEASES. 2015 6 6809 27 [EPIGENETICS IN INFLAMMATORY SYSTEMIC DISEASES]. IN ADDITION TO ANALYSIS OF THE GENETIC CODE, IN RECENT YEARS MORE AND MORE STUDIES HAVE CONCENTRATED ON CHANGES IN THE EPIGENETIC CODE. EPIGENETIC MECHANISMS DETERMINE WHICH GENES IN A CELL ARE TRANSCRIBED AND THUS FORM THE PHENOTYPE OF A CELL. THE EPIGENETIC CODE CAN BE CHANGED BY ENVIRONMENTAL INFLUENCES, WHICH ALLOWS CELLS TO ADAPT TO LONGSTANDING CHANGES IN THE ENVIRONMENT. THEREFORE, IT IS FEASIBLE TO ASSUME THAT EPIGENETIC CHANGES ARE THE MOLECULAR BASIS FOR LONG-TERM EFFECTS OF THE ENVIRONMENT ON DISEASE DEVELOPMENT. IN PARTICULAR IN TUMORS AND CHRONIC INFLAMMATORY DISEASES EPIGENETIC CHANGES WERE FOUND TO CORRELATE WITH DISEASE SEVERITY AND PROGRESSION. KNOWLEDGE ABOUT THESE EPIGENETIC CHANGES MIGHT HELP THAT EPIGENETIC MODIFICATIONS CAN BE USED IN THE FUTURE AS BIOMARKERS, PROGNOSTIC FACTORS AND THERAPEUTIC TARGETS. 2014 7 738 34 CANCER SUSCEPTIBILITY: EPIGENETIC MANIFESTATION OF ENVIRONMENTAL EXPOSURES. CANCER IS A DISEASE THAT RESULTS FROM BOTH GENETIC AND EPIGENETIC CHANGES. DISCORDANT PHENOTYPES AND VARYING INCIDENCES OF COMPLEX DISEASES SUCH AS CANCER IN MONOZYGOTIC TWINS AS WELL AS GENETICALLY IDENTICAL LABORATORY ANIMALS HAVE LONG BEEN ATTRIBUTED TO DIFFERENCES IN ENVIRONMENTAL EXPOSURES. ACCUMULATING EVIDENCE INDICATES, HOWEVER, THAT DISPARITIES IN GENE EXPRESSION RESULTING FROM VARIABLE MODIFICATIONS IN DNA METHYLATION AND CHROMATIN STRUCTURE IN RESPONSE TO THE ENVIRONMENT ALSO PLAY A ROLE IN DIFFERENTIAL SUSCEPTIBILITY TO DISEASE. DESPITE A GROWING CONSENSUS ON THE IMPORTANCE OF EPIGENETICS IN THE ETIOLOGY OF CHRONIC HUMAN DISEASES, THE GENES MOST PRONE TO EPIGENETIC DYSREGULATION ARE INCOMPLETELY DEFINED. MOREOVER, NEITHER THE ENVIRONMENTAL AGENTS MOST STRONGLY AFFECTING THE EPIGENOME NOR THE CRITICAL WINDOWS OF VULNERABILITY TO ENVIRONMENTALLY INDUCED EPIGENETIC ALTERATIONS ARE ADEQUATELY CHARACTERIZED. THESE MAJOR DEFICITS IN KNOWLEDGE MARKEDLY IMPAIR OUR ABILITY TO UNDERSTAND FULLY THE ETIOLOGY OF CANCER AND THE IMPORTANCE OF THE EPIGENOME IN DIAGNOSING AND PREVENTING THIS DEVASTATING DISEASE. 2007 8 3016 36 GENETICS AND EPIGENETICS OF IBD. INFLAMMATORY BOWEL DISEASES (IBD) ARE CHRONIC INTERMITTENT INFLAMMATORY DISORDERS OF THE GASTROINTESTINAL TRACT OF UNKNOWN ETIOLOGY BUT A CLEAR GENETIC PREDISPOSITION. PROMPTED BY THE FIRST INVESTIGATIONS ON IBD FAMILIES AND TWINS, THE GENETIC AND EPIGENETIC STUDIES HAVE PRODUCED AN UNPRECEDENTED AMOUNT OF INFORMATION IN COMPARISON WITH OTHER IMMUNE-MEDIATED OR COMPLEX DISEASES. NEW INFLAMMATORY PATHWAYS AND POSSIBLE MECHANISMS OF ACTION HAVE BEEN DISCLOSED, POTENTIALLY LEADING TO NEW-TARGETED THERAPY. HOWEVER, THE IDENTIFICATION OF GENETIC MARKERS DUE TO THE GREAT DISEASE HETEROGENEITY AND THE OVERWHELMING CONTRIBUTION OF ENVIRONMENTAL RISK FACTORS HAS NOT MODIFIED YET THE DISEASE MANAGEMENT. THE POSSIBILITY FOR THE FUTURE OF A BETTER PREDICTION OF DISEASE COURSE, RESPONSE TO THERAPY AND THERAPY-RELATED ADVERSE EVENTS MAY ALLOW A MORE EFFICIENT AND PERSONALIZED STRATEGY. THIS REVIEW WILL FOCUS ON MORE RECENT DISCOVERIES THAT MAY POTENTIALLY BE OF RELEVANCE IN DAILY CLINICAL PRACTICE. 2020 9 2984 30 GENETIC DETERMINANTS OF POOR RESPONSE TO TREATMENT IN SEVERE ASTHMA. SEVERE ASTHMA IS A MULTIFACTORIAL DISORDER WITH MARKED PHENOTYPIC HETEROGENEITY AND COMPLEX INTERACTIONS BETWEEN GENETICS AND ENVIRONMENTAL RISK FACTORS, WHICH COULD, AT LEAST IN PART, EXPLAIN WHY DURING STANDARD PHARMACOLOGIC TREATMENT, MANY PATIENTS REMAIN POORLY CONTROLLED AND AT AN INCREASED RISK OF AIRWAY REMODELING AND DISEASE PROGRESSION. THE CONCEPT OF "PRECISION MEDICINE" TO BETTER SUIT INDIVIDUAL UNIQUE NEEDS IS AN EMERGING TREND IN THE MANAGEMENT OF CHRONIC RESPIRATORY DISEASES. OVER THE PAST FEW YEARS, GENOME-WIDE ASSOCIATION STUDIES (GWAS) HAVE REVEALED NOVEL PHARMACOGENETIC VARIANTS RELATED TO RESPONSES TO INHALED CORTICOSTEROIDS AND THE CLINICAL EFFICACY OF BRONCHODILATORS. OPTIMAL CLINICAL RESPONSE TO TREATMENT MAY VARY BETWEEN RACIAL/ETHNIC GROUPS OR INDIVIDUALS DUE TO GENETIC DIFFERENCES. IT IS ALSO PLAUSIBLE TO ASSUME THAT EPIGENETIC FACTORS PLAY A KEY ROLE IN THE MODULATION OF GENE EXPRESSION PATTERNS AND INFLAMMATORY CYTOKINES. REMARKABLY, SPECIFIC GENETIC VARIANTS RELATED TO TREATMENT EFFECTIVENESS MAY INDICATE PROMISING PATHWAYS FOR NOVEL THERAPIES IN SEVERE ASTHMA. IN THIS REVIEW, WE PROVIDE A CONCISE UPDATE OF GENETIC DETERMINANTS OF POOR RESPONSE TO TREATMENT IN SEVERE ASTHMA AND FUTURE DIRECTIONS IN THE FIELD. 2021 10 2027 38 EPIGENETIC CHANGES IN CHRONIC INFLAMMATORY DISEASES. THE NUMBER OF PEOPLE DIAGNOSED WITH CHRONIC INFLAMMATORY DISEASES HAS INCREASED NOTEWORTHY IN THE LAST 40 YEARS. SPONDYLOARTHRITIS (SPA), INFLAMMATORY BOWEL DISEASES (IBD), AND PSORIASIS ARE THE MOST FREQUENT CHRONIC INFLAMMATORY DISEASES, RESULTING FROM A COMBINATION OF GENETIC PREDISPOSITION AND ENVIRONMENTAL FACTORS. EPIGENETIC MODIFICATIONS INCLUDE DNA METHYLATION, HISTONE MODIFICATIONS, AND SMALL AND LONG NONCODING RNAS. THEY ARE INFLUENCED BY ENVIRONMENTAL EXPOSURE, LIFE-STYLE, AND AGING AND HAVE RECENTLY BEEN SHOWN TO BE ALTERED IN MANY COMPLEX DISEASES INCLUDING INFLAMMATORY DISEASES. WHILE EPIGENETIC MODIFICATIONS HAVE BEEN WELL CHARACTERIZED IN OTHER DISEASES SUCH AS CANCER AND AUTOIMMUNE DISEASES, KNOWLEDGE ON CHANGES IN INFLAMMATORY DISEASES IS LAGGING BEHIND WITH SOME DISEASE-SPECIFIC DIFFERENCES. WHILE THE DNA METHYLATION PROFILE OF DIFFERENT CELL TYPES IN PATIENTS WITH IBD HAS BEEN RELATIVELY WELL DESCRIBED, LESS IS KNOWN ON CHANGES IMPLICATED IN PSORIASIS, AND NO SYSTEMATIC GENOME-WIDE STUDIES HAVE SO FAR BEEN PERFORMED IN SPA. IN THIS CHAPTER, WE REVIEW IN DETAIL THE REPORTED CHANGES IN PATTERNS OF DNA METHYLATION AND POSTTRANSLATIONAL HISTONE MODIFICATIONS IN CHRONIC INFLAMMATORY DISEASES HIGHLIGHTING POTENTIAL CONNECTIONS BETWEEN DISEASE-ASSOCIATED PATHOPHYSIOLOGICAL CHANGES SUCH AS THE DYSBIOSIS OF THE MICROBIOME OR GENETIC VARIATIONS ASSOCIATED WITH DISEASE SUSCEPTIBILITY AND THE EPIGENOME. WE ALSO DISCUSS IMPORTANT PARAMETERS OF MEANINGFUL EPIGENETIC STUDIES SUCH AS THE USE OF WELL DEFINED, DISEASE-RELEVANT CELL POPULATIONS, AND ELUDE ON THE POTENTIAL FUTURE OF ENGINEERING OF THE EPIGENOME IN INFLAMMATORY DISEASES. 2017 11 3014 34 GENETICS AND EPIGENETICS OF CHRONIC RHINOSINUSITIS. DISCERNING THE GENETICS AND EPIGENETICS OF CHRONIC RHINOSINUSITIS (CRS) MAY OPTIMIZE OUTCOMES THROUGH EARLY DIAGNOSTICS, PERSONALIZED AND NOVEL THERAPEUTICS, AND EARLY PROGNOSTICATION. CRS ASSOCIATED WITH CYSTIC FIBROSIS AND PRIMARY CILIARY DYSKINESIA HAS WELL-CHARACTERIZED GENETIC MUTATIONS. MOST CRS SUBJECTS, HOWEVER, DO NOT EXHIBIT IDENTIFIABLE MONOGENIC ALTERATIONS. CLUSTERING IN RELATED INDIVIDUALS IS SEEN IN CRS WITH NASAL POLYPS. SPOUSES OF SUBJECTS WITH CRS WITHOUT NASAL POLYPS ALSO MAY BE AT INCREASED RISK OF THE SAME DISEASE. THESE OBSERVATIONS GENERATE QUESTIONS ON GENETIC AND ENVIRONMENTAL INFLUENCES IN CRS. GENOME-WIDE ASSOCIATION STUDIES HAVE IDENTIFIED VARIATIONS AND POLYMORPHISMS BETWEEN CRS AND CONTROL SUBJECTS IN GENES RELATED TO INNATE AND ADAPTIVE IMMUNITY. CANDIDATE GENE AND TRANSCRIPTOMICS STUDIES HAVE INVESTIGATED AND IDENTIFIED GENETIC VARIATIONS RELATED TO IMMUNITY, INFLAMMATION, EPITHELIAL BARRIER FUNCTION, STRESS-RESPONSE, ANTIGEN PROCESSING, T-CELL REGULATION, AND CYTOKINES IN CRS. EPIGENETIC STUDIES HAVE IDENTIFIED MECHANISMS THROUGH WHICH ENVIRONMENTAL FACTORS MAY AFFECT THESE GENE FUNCTIONS. HOWEVER, CAUSALITY IS NOT DETERMINED FOR MOST VARIATIONS. INFERENCES DRAWN FROM THESE DATA MUST BE MEASURED BECAUSE MOST INVESTIGATIONS REPORT UNREPLICATED RESULTS FROM SMALL STUDY POPULATIONS. LARGE, REPLICATED STUDIES IN TIGHT COHORTS ACROSS DIVERSE POPULATIONS REMAIN A PRESSING NEED IN STUDYING CRS GENETICS. 2023 12 2333 32 EPIGENETIC REGULATION OF INFLAMMATION: THE METABOLOMICS CONNECTION. EPIGENETIC FACTORS ARE CONSIDERED THE REGULATOR OF COMPLEX MACHINERY BEHIND INFLAMMATORY DISORDERS AND SIGNIFICANTLY CONTRIBUTED TO THE EXPRESSION OF INFLAMMATION-ASSOCIATED GENES. EPIGENETIC MODIFICATIONS MODULATE VARIATION IN THE EXPRESSION PATTERN OF TARGET GENES WITHOUT AFFECTING THE DNA SEQUENCE. THE CURRENT KNOWLEDGE OF EPIGENETIC RESEARCH FOCUSED ON THEIR ROLE IN THE PATHOGENESIS OF VARIOUS INFLAMMATORY DISEASES THAT CAUSES MORBIDITY AND MORTALITY WORLDWIDE. INFLAMMATORY DISEASES ARE CATEGORIZED AS ACUTE AND CHRONIC BASED ON THE DISEASE SEVERITY AND ARE REGULATED BY THE EXPRESSION PATTERN OF VARIOUS GENES. HENCE, UNDERSTANDING THE ROLE OF EPIGENETIC MODIFICATIONS DURING INFLAMMATION PROGRESSION WILL CONTRIBUTE TO THE DISEASE OUTCOMES AND THERAPEUTIC APPROACHES. THIS REVIEW ALSO FOCUSES ON THE METABOLOMICS APPROACH ASSOCIATED WITH THE STUDY OF INFLAMMATORY DISORDERS. INFLAMMATORY RESPONSES AND METABOLIC REGULATION ARE HIGHLY INTEGRATED AND VARIOUS ADVANCED TECHNIQUES ARE ADOPTED TO STUDY THE METABOLIC SIGNATURE MOLECULES. HERE WE DISCUSS SEVERAL METABOLOMICS APPROACHES USED TO LINK INFLAMMATORY DISORDERS AND EPIGENETIC CHANGES. WE PROPOSED THAT DECIPHERING THE MECHANISM BEHIND THE INFLAMMATION-METABOLISM LOOP MAY HAVE IMMENSE IMPORTANCE IN BIOMARKERS RESEARCH AND MAY ACT AS A PRINCIPAL COMPONENT IN DRUG DISCOVERY AS WELL AS THERAPEUTIC APPLICATIONS. 2022 13 3706 34 INFLUENCE OF GENETICS ON DISEASE SUSCEPTIBILITY AND PROGRESSION. FOR MANY CHRONIC DISEASES, THE INFLUENCE OF GENETICS IS COMPLEX AND PHENOTYPES DO NOT CONFORM TO SIMPLE MENDELIAN PATTERNS OF INHERITANCE. DISCUSSED HERE ARE TWO TYPES OF GENETIC INFLUENCES ON HEALTHY AGING. THE FIRST INVOLVES VARIATION IN THE GENE SEQUENCE ITSELF AND HOW THIS MAY INFLUENCE DISEASE SUSCEPTIBILITY, PROGRESSION, AND SEVERITY, INTERACTING WITH OTHER RECOGNIZED RISK FACTORS. THE SECOND INVOLVES EPIGENETIC REGULATORY MECHANISMS THAT MAY POTENTIALLY PROVIDE INSIGHT INTO HOW ENVIRONMENTAL INFLUENCES AFFECT THE EXPRESSED GENOME, THUS IMPROVING OUR UNDERSTANDING OF THE GENETIC MECHANISMS UNDERLYING MULTIFACTORIAL DISEASES. THE INTERLEUKIN-1 FAMILY OF CYTOKINES CAN BE USED TO ILLUSTRATE HOW GENETIC SEQUENCE VARIATION MAY AFFECT SUCH DISEASES. THIS CYTOKINE FAMILY PLAYS A KEY ROLE IN MEDIATING INFLAMMATION, WHICH IS NOW UNDERSTOOD TO BE A CENTRAL COMPONENT OF A GROWING NUMBER OF CHRONIC DISEASES. RECENT WORK HAS REVEALED MANY SEQUENCE VARIATIONS IN THE REGULATORY DNA OF GENES ENCODING IMPORTANT MEMBERS OF THE INTERLEUKIN-1 FAMILY, AND THESE VARIATIONS ARE ASSOCIATED WITH DIFFERENTIAL EFFECTS ON THE INFLAMMATORY RESPONSE. THE INTERACTIONS OF ENVIRONMENTAL FACTORS WITH BOTH DNA SEQUENCE VARIATIONS AND EPIGENETIC MODIFICATIONS ARE LIKELY TO DETERMINE THE PHENOTYPES OF MULTIFACTORIAL DISEASES OF AGING AS WELL AS THE PHENOTYPE OF HEALTHY AGING. 2007 14 4872 42 OUTSIDE-IN HYPOTHESIS REVISITED: THE ROLE OF MICROBIAL, EPITHELIAL, AND IMMUNE INTERACTIONS. OBJECTIVE: OUR UNDERSTANDING OF THE ORIGIN OF ALLERGIC DISEASES HAS INCREASED IN RECENT YEARS, HIGHLIGHTING THE IMPORTANCE OF MICROBIAL DYSBIOSIS AND EPITHELIAL BARRIER DYSFUNCTION IN AFFECTED TISSUES. EXPLORING THE MICROBIAL-EPITHELIAL-IMMUNE CROSSTALK UNDERLYING THE MECHANISMS OF ALLERGIC DISEASES WILL ALLOW THE DEVELOPMENT OF NOVEL PREVENTION AND TREATMENT STRATEGIES FOR ALLERGIC DISEASES. DATA SOURCES: THIS REVIEW SUMMARIZES THE RECENT ADVANCES IN MICROBIAL, EPITHELIAL, AND IMMUNE INTERACTIONS IN ATOPIC DERMATITIS, ALLERGIC RHINITIS, CHRONIC RHINOSINUSITIS, AND ASTHMA. STUDY SELECTIONS: WE PERFORMED A LITERATURE SEARCH, IDENTIFYING RELEVANT RECENT PRIMARY ARTICLES AND REVIEW ARTICLES. RESULTS: DYNAMIC CROSSTALK BETWEEN THE ENVIRONMENTAL FACTORS AND MICROBIAL, EPITHELIAL, AND IMMUNE CELLS IN THE DEVELOPMENT OF ATOPIC DERMATITIS, ALLERGIC RHINITIS, CHRONIC RHINOSINUSITIS, AND ASTHMA UNDERLIES THE PATHOGENESIS OF THESE DISEASES. THERE IS SUBSTANTIAL EVIDENCE IN THE LITERATURE SUGGESTING THAT ENVIRONMENTAL FACTORS DIRECTLY AFFECT BARRIER FUNCTION OF THE EPITHELIUM. IN ADDITION, T-HELPER 2 (T(H)2) CELLS, TYPE 2 INNATE LYMPHOID CELLS, AND THEIR CYTOKINE INTERLEUKIN 13 (IL-13) DAMAGE SKIN AND LUNG BARRIERS. THE EFFECTS OF ENVIRONMENTAL FACTORS MAY AT LEAST IN PART BE MEDIATED BY EPIGENETIC MECHANISMS. HISTONE DEACETYLASE ACTIVATION BY TYPE 2 IMMUNE RESPONSE HAS A MAJOR EFFECT ON LEAKY BARRIERS AND BLOCKING OF HISTONE DEACETYLASE ACTIVITY CORRECTS THE DEFECTIVE BARRIER IN HUMAN AIR-LIQUID INTERFACE CULTURES AND MOUSE MODELS OF ALLERGIC ASTHMA WITH RHINITIS. WE ALSO PRESENT AND DISCUSS A NOVEL DEVICE TO DETECT AND MONITOR SKIN BARRIER DYSFUNCTION, WHICH PROVIDES AN OPPORTUNITY TO RAPIDLY AND ROBUSTLY ASSESS DISEASE SEVERITY. CONCLUSION: A COMPLEX INTERPLAY BETWEEN ENVIRONMENTAL FACTORS, EPITHELIUM, AND THE IMMUNE SYSTEM IS INVOLVED IN THE DEVELOPMENT OF SYSTEMIC ALLERGIC DISEASES. 2020 15 3404 34 HOW EPIGENETICS IMPACTS ON HUMAN DISEASES. EPIGENETICS IS A RAPIDLY GROWING FIELD OF BIOLOGY THAT STUDIES THE CHANGES IN GENE EXPRESSION THAT ARE NOT DUE TO ALTERATIONS IN THE DNA SEQUENCE BUT RATHER THE CHEMICAL MODIFICATIONS OF DNA AND ITS ASSOCIATED PROTEINS. EPIGENETIC MECHANISMS CAN PROFOUNDLY INFLUENCE GENE EXPRESSION, CELL DIFFERENTIATION, TISSUE DEVELOPMENT, AND DISEASE SUSCEPTIBILITY. UNDERSTANDING EPIGENETIC CHANGES IS ESSENTIAL TO ELUCIDATE THE MECHANISMS UNDERLYING THE INCREASINGLY RECOGNIZED ROLE OF ENVIRONMENTAL AND LIFESTYLE FACTORS IN HEALTH AND DISEASE AND THE INTERGENERATIONAL TRANSMISSION OF PHENOTYPES. RECENT STUDIES SUGGEST EPIGENETICS MAY BE CRITICAL IN VARIOUS DISEASES, FROM CARDIOVASCULAR DISEASE AND CANCER TO NEURODEVELOPMENTAL AND NEURODEGENERATIVE DISORDERS. EPIGENETIC MODIFICATIONS ARE POTENTIALLY REVERSIBLE AND COULD PROVIDE NEW THERAPEUTIC AVENUES FOR TREATING THESE DISEASES USING EPIGENETIC MODULATORS. MOREOVER, EPIGENETICS PROVIDE INSIGHT INTO DISEASE PATHOGENESIS AND BIOMARKERS FOR DISEASE DIAGNOSIS AND RISK STRATIFICATION. NEVERTHELESS, EPIGENETIC INTERVENTIONS HAVE THE POTENTIAL FOR UNINTENDED CONSEQUENCES AND MAY POTENTIALLY LEAD TO INCREASED RISKS OF UNEXPECTED OUTCOMES, SUCH AS ADVERSE DRUG REACTIONS, DEVELOPMENTAL ABNORMALITIES, AND CANCER. THEREFORE, RIGOROUS STUDIES ARE ESSENTIAL TO MINIMIZE THE RISKS ASSOCIATED WITH EPIGENETIC THERAPIES AND TO DEVELOP SAFE AND EFFECTIVE INTERVENTIONS FOR IMPROVING HUMAN HEALTH. THIS ARTICLE PROVIDES A SYNTHETIC AND HISTORICAL VIEW OF THE ORIGIN OF EPIGENETICS AND SOME OF THE MOST RELEVANT ACHIEVEMENTS. 2023 16 4392 34 MODIFIABLE RISK FACTORS IN PERIODONTAL DISEASE: EPIGENETIC REGULATION OF GENE EXPRESSION IN THE INFLAMMATORY RESPONSE. EPIGENETICS AS A MODIFIABLE RISK FACTOR IN PERIODONTAL DISEASES HAS BEEN INVESTIGATED IN LIGHT OF THE CURRENT KNOWLEDGE OF HOW CHRONIC INFECTION AND INFLAMMATION CAN AFFECT GENE-SPECIFIC EPIGENETIC REPROGRAMMING IN PERIODONTAL TISSUES. EPIGENOMIC PROGRAMMING MIGHT BE PARTICULARLY SENSITIVE TO ENVIRONMENTAL INFLUENCES, AND A COMBINATION OF PHYSIOLOGICAL STRESSORS AND ENVIRONMENTAL EXPOSURES APPEARS TO AFFECT THE EPIGENOMIC PROGRAM ACQUIRED BY A CELL DURING DIFFERENTIATION AND THROUGHOUT THE CELLULAR LINEAGE LIFESPAN. VIRAL AND BACTERIAL INFECTIONS CAN ESTABLISH SEVERAL TYPES OF EPIGENETIC MODIFICATIONS, WHICH SOMETIMES ENGAGE IN A COMPLEX EPIGENETIC CROSSTALK ALSO REFLECTING IN THE ESTABLISHMENT AND PROGRESS OF PERIODONTAL DISEASES. THE INFLAMMATORY AND METABOLIC STATES OF THE PERIODONTAL TISSUES ARE DRIVEN BY THE INFECTIOUS STIMULI, AND THE MAGNITUDE OF THE CELLULAR AND MOLECULAR SIGNATURE RESPONSE IS FURTHER DICTATED BY THE HOST GENETIC AND EPIGENETIC TRAITS ASSOCIATED WITH VARIOUS SYSTEMIC EXPOSURES, INCLUDING SMOKING, OBESITY AND DIABETES/HYPERGLYCEMIA. THIS REVIEW DISCUSSES THE ADVANCES IN EPIGENETICS, FOCUSING ON THE ROLE OF DNA METHYLATION IN THE PATHOGENESIS OF PERIODONTAL DISEASE AND THE POTENTIAL OF EPIGENETIC THERAPY. 2014 17 4273 31 MICROBIOTA AND EPIGENETICS: HEALTH IMPACT. EPIGENETIC CHANGES ASSOCIATED WITH DISEASE DEVELOPMENT AND PROGRESSIONS ARE OF INCREASING IMPORTANCE BECAUSE OF THEIR POTENTIAL DIAGNOSTIC AND THERAPEUTIC APPLICATIONS. SEVERAL EPIGENETIC CHANGES ASSOCIATED WITH CHRONIC METABOLIC DISORDERS HAVE BEEN STUDIED IN VARIOUS DISEASES. EPIGENETIC CHANGES ARE MOSTLY MODULATED BY ENVIRONMENTAL FACTORS, INCLUDING THE HUMAN MICROBIOTA LIVING IN DIFFERENT PARTS OF OUR BODIES. THE MICROBIAL STRUCTURAL COMPONENTS AND THE MICROBIALLY DERIVED METABOLITES DIRECTLY INTERACT WITH HOST CELLS, THEREBY MAINTAINING HOMEOSTASIS. MICROBIOME DYSBIOSIS, ON THE OTHER HAND, IS KNOWN TO PRODUCE ELEVATED LEVELS OF DISEASE-LINKED METABOLITES, WHICH MAY DIRECTLY AFFECT A HOST METABOLIC PATHWAY OR INDUCE EPIGENETIC CHANGES THAT CAN LEAD TO DISEASE DEVELOPMENT. DESPITE THEIR IMPORTANT ROLE IN HOST PHYSIOLOGY AND SIGNAL TRANSDUCTION, THERE HAS BEEN LITTLE RESEARCH INTO THE MECHANICS AND PATHWAYS ASSOCIATED WITH EPIGENETIC MODIFICATIONS. THIS CHAPTER FOCUSES ON THE RELATIONSHIP BETWEEN MICROBES AND THEIR EPIGENETIC EFFECTS IN DISEASED PATHOLOGY, AS WELL AS ON THE REGULATION AND METABOLISM OF THE DIETARY OPTIONS AVAILABLE TO THE MICROBES. FURTHERMORE, THIS CHAPTER ALSO PROVIDES A PROSPECTIVE LINK BETWEEN THESE TWO IMPORTANT PHENOMENA, TERMED "MICROBIOME AND EPIGENETICS." 2023 18 3028 31 GENETICS OF COMPLEX AIRWAY DISEASE. THE PAST 3 YEARS HAVE SEEN HIGHLY SIGNIFICANT GENETIC EFFECTS IDENTIFIED FOR A WIDE VARIETY OF COMMON COMPLEX DISEASES, INCLUDING THE AIRWAY DISORDERS OF ASTHMA AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE. IT APPEARS THAT ONLY A PORTION OF THE GENETICALLY MEDIATED SUSCEPTIBILITY TO COMPLEX DISEASES HAS BEEN IDENTIFIED, AND THERE IS MUCH LEFT TO BE DISCOVERED. THIS REVIEW BRIEFLY DESCRIBES THE RESULTS OF THE GENOME-WIDE ASSOCIATION STUDIES OF ASTHMA AND GIVES AN OVERVIEW OF THE PARALLEL AND INCREASINGLY LARGE-SCALE STUDIES THAT ARE TAKING PLACE WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE. THE FUTURE IMPACT IS DISCUSSED OF TECHNOLOGICAL ADVANCES THAT ALLOW INCREASINGLY LARGE-SCALE GENE EXPRESSION STUDIES, NEXT-GENERATION SEQUENCING, AND GENOME-WIDE TESTING FOR EPIGENETIC EFFECTS. THE USE OF GENETIC TECHNOLOGY TO EXAMINE THE AIRWAY MICROBIOTA THAT INTERACT WITH THE MUCOSA IN HEALTH AND DISEASE IS DESCRIBED. 2011 19 1546 30 DNA METHYLATION IN NASAL EPITHELIUM: STRENGTHS AND LIMITATIONS OF AN EMERGENT BIOMARKER FOR CHILDHOOD ASTHMA. ASTHMA IS ONE OF THE MOST WIDESPREAD CHRONIC RESPIRATORY CONDITIONS. THIS DISEASE PRIMARILY DEVELOPS IN CHILDHOOD AND IS INFLUENCED BY DIFFERENT FACTORS, MAINLY GENETICS AND ENVIRONMENTAL FACTORS. DNA METHYLATION IS AN EPIGENETIC MECHANISM WHICH MAY REPRESENT A BRIDGE BETWEEN THESE TWO FACTORS, PROVIDING A TOOL TO COMPREHEND THE INTERACTION BETWEEN GENETICS AND ENVIRONMENT. MOST EPIDEMIOLOGICAL STUDIES IN THIS FIELD HAVE BEEN CONDUCTED USING BLOOD SAMPLES, ALTHOUGH DNA METHYLATION MARKS IN BLOOD MAY NOT BE RELIABLE FOR DRAWING EXHAUSTIVE CONCLUSIONS ABOUT DNA METHYLATION IN THE AIRWAYS. BECAUSE OF THE ROLE OF NASAL EPITHELIUM IN ASTHMA AND THE TISSUE SPECIFICITY OF DNA METHYLATION, STUDYING THE RELATIONSHIP BETWEEN DNA METHYLATION AND CHILDHOOD ASTHMA MIGHT REVEAL CRUCIAL INFORMATION ABOUT THIS WIDESPREAD RESPIRATORY DISEASE. THE PURPOSE OF THIS REVIEW IS TO DESCRIBE CURRENT FINDINGS IN THIS FIELD OF RESEARCH. WE WILL PRESENT A VIEWPOINT OF SELECTED STUDIES, CONSIDER STRENGTHS AND LIMITATIONS, AND PROPOSE FUTURE RESEARCH IN THIS AREA. 2020 20 2558 35 EPIGENETICS IN SUSCEPTIBILITY, PROGRESSION, AND DIAGNOSIS OF PERIODONTITIS. PERIODONTITIS IS CHARACTERIZED BY IRREVERSIBLE DESTRUCTION OF PERIODONTAL TISSUE. AT PRESENT, THE ACCEPTED ETIOLOGY OF PERIODONTITIS IS BASED ON A THREE-FACTOR THEORY INCLUDING PATHOGENIC BACTERIA, HOST FACTORS, AND ACQUIRED FACTORS. PERIODONTITIS DEVELOPMENT USUALLY TAKES A DECADE OR LONGER AND IS THEREFORE CALLED CHRONIC PERIODONTITIS (CP). TO SEARCH FOR GENETIC FACTORS ASSOCIATED WITH CP, SEVERAL GENOME-WIDE ASSOCIATION STUDY (GWAS) ANALYSES WERE CONDUCTED; HOWEVER, POLYMORPHISMS ASSOCIATED WITH CP HAVE NOT BEEN IDENTIFIED. EPIGENETICS, ON THE OTHER HAND, INVOLVES ACQUIRED TRANSCRIPTIONAL REGULATORY MECHANISMS DUE TO REVERSIBLY ALTERED CHROMATIN ACCESSIBILITY. EPIGENETIC STATUS IS A CONDITION SPECIFIC TO EACH TISSUE AND CELL, MOSTLY DETERMINED BY THE RESPONSES OF HOST CELLS TO STIMULATIONS BY LOCAL FACTORS, LIKE BACTERIAL INFLAMMATION, AND SYSTEMIC FACTORS SUCH AS NUTRITION STATUS, METABOLIC DISEASES, AND HEALTH CONDITIONS. SIGNIFICANTLY, EPIGENETIC STATUS HAS BEEN LINKED WITH THE ONSET AND PROGRESSION OF SEVERAL ACQUIRED DISEASES. THUS, EPIGENETIC FACTORS IN PERIODONTAL TISSUES ARE ATTRACTIVE TARGETS FOR PERIODONTITIS DIAGNOSIS AND TREATMENTS. IN THIS REVIEW, WE INTRODUCE ACCUMULATING EVIDENCE TO REVEAL THE EPIGENETIC BACKGROUND EFFECTS RELATED TO PERIODONTITIS CAUSED BY GENETIC FACTORS, SYSTEMIC DISEASES, AND LOCAL ENVIRONMENTAL FACTORS, SUCH AS SMOKING, AND CLARIFY THE UNDERLYING MECHANISMS BY WHICH EPIGENETIC ALTERATION INFLUENCES THE SUSCEPTIBILITY OF PERIODONTITIS. 2022