1 3411 89 HP1GAMMA PREVENTS ACTIVATION OF THE CGAS/STING PATHWAY BY PRESERVING NUCLEAR ENVELOPE AND GENOMIC INTEGRITY IN COLON ADENOCARCINOMA CELLS. CHRONIC INFLAMMATORY PROCESSES IN THE INTESTINE RESULT IN SERIOUS CONDITIONS SUCH AS INFLAMMATORY BOWEL DISEASE (IBD) AND CANCER. AN INCREASED DETECTION OF CYTOPLASMIC DNA SENSORS HAS BEEN REPORTED IN THE IBD COLON MUCOSA, SUGGESTING THEIR CONTRIBUTION IN MUCOSAL INFLAMMATION. YET, THE MECHANISMS ALTERING DNA HOMEOSTASIS AND TRIGGERING THE ACTIVATION OF DNA SENSORS REMAIN POORLY UNDERSTOOD. IN THIS STUDY, WE SHOW THAT THE EPIGENETIC REGULATOR HP1GAMMA PLAYS A ROLE IN PRESERVING NUCLEAR ENVELOPE AND GENOMIC INTEGRITY IN ENTEROCYTIC CELLS, THEREBY PROTECTING AGAINST THE PRESENCE OF CYTOPLASMIC DNA. ACCORDINGLY, HP1 LOSS OF FUNCTION LED TO THE INCREASED DETECTION OF CGAS/STING, A CYTOPLASMIC DNA SENSOR THAT TRIGGERS INFLAMMATION. THUS, IN ADDITION TO ITS ROLE AS A TRANSCRIPTIONAL SILENCER, HP1GAMMA MAY ALSO EXERT ANTI-INFLAMMATORY PROPERTIES BY PREVENTING THE ACTIVATION OF THE ENDOGENOUS CYTOPLASMIC DNA RESPONSE IN THE GUT EPITHELIUM. 2023 2 2233 35 EPIGENETIC MODIFICATIONS OF THE NUCLEAR FACTOR KAPPA B SIGNALLING PATHWAY AND ITS IMPACT ON INFLAMMATORY BOWEL DISEASE. BACKGROUND: INFLAMMATORY BOWEL DISEASE (IBD) IS A MULTIFACTORIAL CONDITION INFLUENCED BY THE IMMUNE SYSTEM, THE INTESTINAL MICROBIOTA, ENVIRONMENTAL FACTORS, GENETIC AND EPIGENETIC FACTORS. GENETIC- AND ENVIRONMENT- INDUCED DYSREGULATION OF THE NUCLEAR FACTOR-KAPPA B (NF-KAPPAB) TRANSCRIPTION FACTOR PATHWAY HAS BEEN LINKED TO IBD PATHOGENESIS. OBJECTIVE: TO ASSESS THE CURRENT EVIDENCE IN RELATION TO THE CONTRIBUTION OF THE CLASSICAL AND ALTERNATIVE NF-KAPPAB PATHWAYS IN IBD AND TO DISCUSS THE EPIGENETIC MECHANISMS THAT IMPACT ON NF-KAPPAB FUNCTION. METHODS: A MEDLINE SEARCH FOR 'NF-KAPPAB/NF-KAPPAB', IN COMBINATION WITH TERMS INCLUDING 'INFLAMMATORY BOWEL DISEASE/IBD', 'INTESTINAL INFLAMMATION', 'CROHN'S DISEASE', 'ULCERATIVE COLITIS', 'COLITIS'; 'EPIGENETICS', 'DNA METHYLATION', 'HISTONES', 'MICRORNAS/MIRNAS' AND 'SHORT NON-CODING/LONG NON-CODING RNAS' WAS PERFORMED. RESULTS: BOTH NF-KAPPAB PATHWAYS CONTRIBUTE TO THE CHRONIC INFLAMMATION UNDERLYING IBD BY REGULATING THE INFLAMMATORY IMMUNE RESPONSES AND HOMEOSTASIS OF THE INTESTINAL EPITHELIUM (CLASSICAL PATHWAY) OR REGULATING BOWEL INFLAMMATION AND EPITHELIAL MICROFOLD (M) CELL FUNCTION (ALTERNATIVE PATHWAY). DNA METHYLATION IS A COMMON EPIGENETIC MODIFICATION IN INTESTINAL INFLAMMATION, INCLUDING NFKB1 AND RELA LOCI. CONVERSELY, LITTLE IS UNDERSTOOD REGARDING EPIGENETIC EFFECTS ON GENES ENCODING OTHER NF-KAPPAB SUBUNITS, PARTICULARLY THOSE OF THE ALTERNATIVE PATHWAY, AND IN THE CONTEXT OF IBD. HOWEVER, NF-KAPPAB INTERACTION WITH CHROMATIN MODIFIERS IS ALSO SEEN TO BE AN ESSENTIAL MECHANISM OF REGULATION OF DOWNSTREAM TARGET GENES RELEVANT TO NF-KAPPAB-MEDIATED INFLAMMATORY RESPONSES. CONCLUSION: FURTHER RESEARCH IS CLEARLY WARRANTED IN THIS AREA, AS UNDERSTANDING THE CELL-SPECIFIC REGULATION OF THE NF-KAPPAB PATHWAYS WILL BRING RESEARCHERS INTO A POSITION TO ACHIEVE MORE EFFICIENT STRATIFICATION OF IBD PATIENTS, AND MORE TARGETED AND EFFECTIVE CHOICE OF TREATMENT. 2021 3 2036 21 EPIGENETIC CHANGES OF THE IMMUNE SYSTEM WITH ROLE IN TUMOR DEVELOPMENT. TUMOR DEVELOPMENT IS CLOSELY RELATED TO CHRONIC INFLAMMATION AND TO EVASION OF IMMUNE DEFENSE MECHANISMS BY NEOPLASTIC CELLS. THE MEDIATORS OF THE INFLAMMATORY PROCESS AS WELL AS PROTEINS INVOLVED IN IMMUNE RESPONSE OR IMMUNE RESPONSE EVASION CAN BE SUBJECT TO VARIOUS EPIGENETIC CHANGES SUCH AS METHYLATION, ACETYLATION, OR PHOSPHORYLATION. SOME OF THESE, SUCH AS CYTOKINE SUPPRESSORS, ARE UNDERGOING REPRESSION THROUGH EPIGENETIC CHANGES, AND OTHERS SUCH AS CYTOKINES OR CHEMOKINES ARE UNDERGOING ACTIVATION THROUGH EPIGENETIC CHANGES, BOTH MODIFICATIONS HAVING AS A RESULT TUMOR PROGRESSION. THE ACTIVATING CHANGES CAN AFFECT THE RECEPTOR MOLECULES INVOLVED IN IMMUNE RESPONSE AND THESE PROMOTE INFLAMMATION AND SUBSEQUENTLY TUMOR DEVELOPMENT WHILE THE INACTIVATING CHANGES SEEM TO BE RELATED TO THE TUMOR REGRESSION PROCESS. THE PROTEINS INVOLVED IN ANTIGEN PRESENTATION, AND, THEREFORE IN IMMUNE RESPONSE ESCAPE, SUCH AS CLASSICAL HLA PROTEINS AND RELATED APM (ANTIGEN PRESENTATION MACHINERY) WITH THEIR EPIGENETIC CHANGES CONTRIBUTE TO THE TUMOR DEVELOPMENT PROCESS, EITHER TO TUMOR PROGRESSION OR REGRESSION, DEPENDING ON THE IMMUNE EFFECTOR CELLS THAT ARE IN PLAY. 2018 4 2228 31 EPIGENETIC MODIFICATIONS OF HISTONES IN PERIODONTAL DISEASE. PERIODONTITIS IS A CHRONIC INFECTIOUS DISEASE DRIVEN BY DYSBIOSIS, AN IMBALANCE BETWEEN COMMENSAL BACTERIA AND THE HOST ORGANISM. PERIODONTITIS IS A LEADING CAUSE OF TOOTH LOSS IN ADULTS AND OCCURS IN ABOUT 50% OF THE US POPULATION. IN ADDITION TO THE CLINICAL CHALLENGES ASSOCIATED WITH TREATING PERIODONTITIS, THE PROGRESSION AND CHRONIC NATURE OF THIS DISEASE SERIOUSLY AFFECT HUMAN HEALTH. EMERGING EVIDENCE SUGGESTS THAT PERIODONTITIS IS ASSOCIATED WITH MECHANISMS BEYOND BACTERIA-INDUCED PROTEIN AND TISSUE DEGRADATION. HERE, WE HYPOTHESIZE THAT BACTERIA ARE ABLE TO INDUCE EPIGENETIC MODIFICATIONS IN ORAL EPITHELIAL CELLS MEDIATED BY HISTONE MODIFICATIONS. IN THIS STUDY, WE FOUND THAT DYSBIOSIS IN VIVO LED TO EPIGENETIC MODIFICATIONS, INCLUDING ACETYLATION OF HISTONES AND DOWNREGULATION OF DNA METHYLTRANSFERASE 1. IN ADDITION, IN VITRO EXPOSURE OF ORAL EPITHELIAL CELLS TO LIPOPOLYSACCHARIDES RESULTED IN HISTONE MODIFICATIONS, ACTIVATION OF TRANSCRIPTIONAL COACTIVATORS, SUCH AS P300/CBP, AND ACCUMULATION OF NUCLEAR FACTOR-KAPPAB (NF-KAPPAB). GIVEN THAT ORAL EPITHELIAL CELLS ARE THE FIRST LINE OF DEFENSE FOR THE PERIODONTIUM AGAINST BACTERIA, WE ALSO EVALUATED WHETHER ACTIVATION OF PATHOGEN RECOGNITION RECEPTORS INDUCED HISTONE MODIFICATIONS. WE FOUND THAT ACTIVATION OF THE TOLL-LIKE RECEPTORS 1, 2, AND 4 AND THE NUCLEOTIDE-BINDING OLIGOMERIZATION DOMAIN PROTEIN 1 INDUCED HISTONE ACETYLATION IN ORAL EPITHELIAL CELLS. OUR FINDINGS CORROBORATE THE EMERGING CONCEPT THAT EPIGENETIC MODIFICATIONS PLAY A ROLE IN THE DEVELOPMENT OF PERIODONTITIS. 2016 5 3799 25 INTERPLAY BETWEEN INFLAMMATION AND EPIGENETIC CHANGES IN CANCER. IMMUNE RESPONSES CAN SUPPRESS TUMORIGENESIS, BUT ALSO CONTRIBUTE TO CANCER INITIATION AND PROGRESSION SUGGESTING A COMPLEX INTERACTION BETWEEN THE IMMUNE SYSTEM AND CANCER. EPIGENETIC ALTERATIONS, WHICH ARE HERITABLE CHANGES IN GENE EXPRESSION WITHOUT CHANGES TO THE DNA SEQUENCE, ALSO PLAY A ROLE IN CARCINOGENESIS THROUGH SILENCING EXPRESSION OF TUMOR SUPPRESSOR GENES AND ACTIVATING ONCOGENIC SIGNALING. INTERESTINGLY, EPITHELIAL CELLS AT SITES OF CHRONIC INFLAMMATION UNDERGO DNA METHYLATION ALTERATIONS THAT ARE SIMILAR TO THOSE PRESENT IN CANCER CELLS, SUGGESTING THAT INFLAMMATION MAY INITIATE CANCER-SPECIFIC EPIGENETIC CHANGES IN EPITHELIAL CELLS. FURTHERMORE, EPIGENETIC CHANGES OCCUR DURING IMMUNE CELL DIFFERENTIATION AND PARTICIPATE IN REGULATING THE IMMUNE RESPONSE, INCLUDING THE REGULATION OF INFLAMMATORY CYTOKINES. CANCER CELLS UTILIZE EPIGENETIC SILENCING OF IMMUNE-RELATED GENES TO EVADE THE IMMUNE RESPONSE. THIS CHAPTER WILL DETAIL THE INTERACTIONS BETWEEN INFLAMMATION AND EPIGENETICS IN TUMOR INITIATION, PROMOTION, AND IMMUNE EVASION AND HOW THESE CONNECTIONS ARE BEING LEVERAGED IN CANCER PREVENTION AND TREATMENT. 2016 6 5566 27 ROLE OF INFLAMMATION IN THE DEVELOPMENT OF COLORECTAL CANCER. CHRONIC INFLAMMATION CAN LEAD TO THE DEVELOPMENT OF MANY DISEASES, INCLUDING CANCER. INFLAMMATORY BOWEL DISEASE (IBD) THAT INCLUDES BOTH ULCERATIVE COLITIS (UC) AND CROHNMP'S DISEASE (CD) ARE RISK FACTORS FOR THE DEVELOPMENT OF COLORECTAL CANCER (CRC). MANY CYTOKINES PRODUCED PRIMARILY BY THE GUT IMMUNE CELLS EITHER DURING OR IN RESPONSE TO LOCALIZED INFLAMMATION IN THE COLON AND RECTUM ARE KNOWN TO STIMULATE THE COMPLEX INTERACTIONS BETWEEN THE DIFFERENT CELL TYPES IN THE GUT ENVIRONMENT RESULTING IN ACUTE INFLAMMATION. SUBSEQUENTLY, CHRONIC INFLAMMATION, TOGETHER WITH GENETIC AND EPIGENETIC CHANGES, HAVE BEEN SHOWN TO LEAD TO THE DEVELOPMENT AND PROGRESSION OF CRC. VARIOUS CELL TYPES PRESENT IN THE COLON, SUCH AS ENTEROCYTES, PANETH CELLS, GOBLET CELLS, AND MACROPHAGES, EXPRESS RECEPTORS FOR INFLAMMATORY CYTOKINES AND RESPOND TO TUMOR NECROSIS FACTOR-ALPHA (TNF-ALPHA), INTERLEUKIN-1 BETA (IL-1BETA), IL-6, AND OTHER CYTOKINES. AMONG THE SEVERAL CYTOKINES PRODUCED, TNF-ALPHA AND IL-1BETA ARE THE KEY PRO-INFLAMMATORY MOLECULES THAT PLAY CRITICAL ROLES IN THE DEVELOPMENT OF CRC. THE CURRENT REVIEW IS INTENDED TO CONSOLIDATE THE PUBLISHED FINDINGS TO FOCUS ON THE ROLE OF PRO-INFLAMMATORY CYTOKINES, NAMELY TNF-ALPHA AND IL-1BETA, ON INFLAMMATION (AND THE ALTERED IMMUNE RESPONSE) IN THE GUT, TO BETTER UNDERSTAND THE DEVELOPMENT OF CRC IN IBD, USING VARIOUS EXPERIMENTAL MODEL SYSTEMS, PRECLINICAL AND CLINICAL STUDIES. MOREOVER, THIS REVIEW ALSO HIGHLIGHTS THE CURRENT THERAPEUTIC STRATEGIES AVAILABLE (MONOTHERAPY AND COMBINATION THERAPY) TO ALLEVIATE THE SYMPTOMS OR TREAT INFLAMMATION-ASSOCIATED CRC BY USING MONOCLONAL ANTIBODIES OR APTAMERS TO BLOCK PRO-INFLAMMATORY MOLECULES, INHIBITORS OF TYROSINE KINASES IN THE INFLAMMATORY SIGNALING CASCADE, COMPETITIVE INHIBITORS OF PRO-INFLAMMATORY MOLECULES, AND THE NUCLEIC ACID DRUGS LIKE SMALL ACTIVATING RNAS (SARNAS) OR MICRORNA (MIRNA) MIMICS TO ACTIVATE TUMOR SUPPRESSOR OR REPRESS ONCOGENE/PRO-INFLAMMATORY CYTOKINE GENE EXPRESSION. 2021 7 6532 22 TRANSCRIPTIONAL REGULATION OF INFLAMMASOMES. INFLAMMASOMES ARE MULTIMOLECULAR COMPLEXES WITH POTENT INFLAMMATORY ACTIVITY. AS SUCH, THEIR ACTIVITY IS TIGHTLY REGULATED AT THE TRANSCRIPTIONAL AND POST-TRANSCRIPTIONAL LEVELS. IN THIS REVIEW, WE PRESENT THE TRANSCRIPTIONAL REGULATION OF INFLAMMASOME GENES FROM SENSORS (E.G., NLRP3) TO SUBSTRATES (E.G., IL-1BETA). LINEAGE-DETERMINING TRANSCRIPTION FACTORS SHAPE INFLAMMASOME RESPONSES IN DIFFERENT CELL TYPES WITH PROFOUND CONSEQUENCES ON THE RESPONSIVENESS TO INFLAMMASOME-ACTIVATING STIMULI. PRO-INFLAMMATORY SIGNALS (STERILE OR MICROBIAL) HAVE A KEY TRANSCRIPTIONAL IMPACT ON INFLAMMASOME GENES, WHICH IS LARGELY MEDIATED BY NF-KAPPAB AND THAT TRANSLATES INTO HIGHER ANTIMICROBIAL IMMUNE RESPONSES. FURTHERMORE, DIVERSE INTRINSIC (E.G., CIRCADIAN CLOCK, METABOLITES) OR EXTRINSIC (E.G., XENOBIOTICS) SIGNALS ARE INTEGRATED BY SIGNAL-DEPENDENT TRANSCRIPTION FACTORS AND CHROMATIN STRUCTURE CHANGES TO MODULATE TRANSCRIPTIONALLY INFLAMMASOME RESPONSES. FINALLY, ANTI-INFLAMMATORY SIGNALS (E.G., IL-10) COUNTERBALANCE INFLAMMASOME GENES INDUCTION TO LIMIT DELETERIOUS INFLAMMATION. TRANSCRIPTIONAL REGULATIONS THUS APPEAR AS THE FIRST LINE OF INFLAMMASOME REGULATION TO RAISE THE DEFENSE LEVEL IN FRONT OF STRESS AND INFECTIONS BUT ALSO TO LIMIT EXCESSIVE OR CHRONIC INFLAMMATION. 2020 8 3921 32 LINKING INFLAMMATION TO CELL CYCLE PROGRESSION. RISK OF GASTROINTESTINAL CANCERS IS CLOSELY RELATED TO INCREASED LEVELS OF OXIDANTS IN THE BALANCE BETWEEN OXIDANT AND ANTI-OXIDANT AGENTS. A POSSIBLE EXPLANATION OF THIS EPIDEMIOLOGICAL OBSERVATION IS THE LOCAL LOSS OF THE EPITHELIAL BARRIER FUNCTION WITH A FOCAL INFLAMMATORY RESPONSE. ACCORDINGLY, CHRONIC INFLAMMATORY DISEASES REPRESENT WELL-KNOWN RISK FACTORS FOR CANCER AND, ON THE OTHER HAND, IT IS KNOWN THAT ANTI-INFLAMMATORY AGENTS, DEMULCENTS AND ANTIOXIDANTS MARKEDLY INHIBIT THE DEVELOPMENT OF COLON CANCER IN ANIMAL MODELS AS WELL IN HUMANS. AT MOLECULAR LEVEL A KEY ROLE IN THE PROCESS THAT LINK INFLAMMATION TO CELLULAR TRANSFORMATION SEEMS TO BE PLAYED BY ACTIVATION OF CYCLOOXYGENASE-2 (COX-2) TOGETHER WITH PRODUCTION OF REACTIVE OXYGEN INTERMEDIATE (ROI). BOTH THESE EVENTS HAVE BEEN STRICTLY LINKED WITH CELL PROLIFERATION AND TRANSFORMATION, ALTHOUGH THE INTRACELLULAR PATHWAYS INVOLVED IN THESE PROCESSES ARE STILL NOT COMPLETELY UNDERSTOOD. THE UNCONTROLLED PROLIFERATION, WHICH IS A LANDMARK OF CELLULAR TRANSFORMATION, IS ACCOMPANIED BY THE DEREGULATION OF PROTEINS INVOLVED IN THE CONTROL OF CELL CYCLE CHECKPOINTS. ALTERED EXPRESSION AND FUNCTION OF CYCLOOXYGENASE AND NITRIC OXIDE SYNTHASE SEEM TO INFLUENCE, AMONG OTHERS, THE EXPRESSION OF PROTEINS INVOLVED IN THE REGULATION OF CELL CYCLE PROGRESSION. SIMILARLY, ANTI-INFLAMMATORY AND ANTIOXIDANT AGENTS MAY ALSO ACT ON THE EXPRESSION AND FUNCTION OF SEVERAL CELL CYCLE REGULATING PROTEINS. UNDERSTANDING THE MECHANISMS BY WHICH CHRONIC INFLAMMATION CONTRIBUTES TO GENETIC AND EPIGENETIC CHANGES INVOLVED IN THE REGULATION OF CRITICAL CELL CYCLE CHECKPOINTS MAY HELP TO DEVELOP MORE AND MORE SPECIFIC TREATMENT STRATEGIES FOR REDUCING MALIGNANT TRANSFORMATION OF THESE INFLAMMATORY DISEASES. 2004 9 1864 28 EMERGING AVENUES LINKING INFLAMMATION AND CANCER. THE ROLE OF INFLAMMATION IN CARCINOGENESIS HAS BEEN EXTENSIVELY INVESTIGATED AND WELL DOCUMENTED. MANY BIOCHEMICAL PROCESSES THAT ARE ALTERED DURING CHRONIC INFLAMMATION HAVE BEEN IMPLICATED IN TUMORIGENESIS. THESE INCLUDE SHIFTING CELLULAR REDOX BALANCE TOWARD OXIDATIVE STRESS; INDUCTION OF GENOMIC INSTABILITY; INCREASED DNA DAMAGE; STIMULATION OF CELL PROLIFERATION, METASTASIS, AND ANGIOGENESIS; DEREGULATION OF CELLULAR EPIGENETIC CONTROL OF GENE EXPRESSION; AND INAPPROPRIATE EPITHELIAL-TO-MESENCHYMAL TRANSITION. A WIDE ARRAY OF PROINFLAMMATORY CYTOKINES, PROSTAGLANDINS, NITRIC OXIDE, AND MATRICELLULAR PROTEINS ARE CLOSELY INVOLVED IN PREMALIGNANT AND MALIGNANT CONVERSION OF CELLS IN A BACKGROUND OF CHRONIC INFLAMMATION. INAPPROPRIATE TRANSCRIPTION OF GENES ENCODING INFLAMMATORY MEDIATORS, SURVIVAL FACTORS, AND ANGIOGENIC AND METASTATIC PROTEINS IS THE KEY MOLECULAR EVENT IN LINKING INFLAMMATION AND CANCER. ABERRANT CELL SIGNALING PATHWAYS COMPRISING VARIOUS KINASES AND THEIR DOWNSTREAM TRANSCRIPTION FACTORS HAVE BEEN IDENTIFIED AS THE MAJOR CONTRIBUTORS IN ABNORMAL GENE EXPRESSION ASSOCIATED WITH INFLAMMATION-DRIVEN CARCINOGENESIS. THE POSTTRANSCRIPTIONAL REGULATION OF GENE EXPRESSION BY MICRORNAS ALSO PROVIDES THE MOLECULAR BASIS FOR LINKING INFLAMMATION TO CANCER. THIS REVIEW HIGHLIGHTS THE MULTIFACETED ROLE OF INFLAMMATION IN CARCINOGENESIS IN THE CONTEXT OF ALTERED CELLULAR REDOX SIGNALING. 2012 10 1150 29 CONNECTION BETWEEN INFLAMMATION AND CARCINOGENESIS IN GASTROINTESTINAL TRACT: FOCUS ON TGF-BETA SIGNALING. INFLAMMATION IS A PRIMARY DEFENSE PROCESS AGAINST VARIOUS EXTRACELLULAR STIMULI, SUCH AS VIRUSES, PATHOGENS, FOODS, AND ENVIRONMENTAL POLLUTANTS. WHEN CELLS RESPOND TO STIMULI FOR SHORT PERIODS OF TIME, IT RESULTS IN ACUTE OR PHYSIOLOGICAL INFLAMMATION. HOWEVER, IF THE STIMULATION IS SUSTAINED FOR LONGER TIME OR A PATHOLOGICAL STATE OCCURS, IT IS KNOWN AS CHRONIC OR PATHOLOGICAL INFLAMMATION. SEVERAL STUDIES HAVE SHOWN THAT TUMORIGENESIS IN THE GASTROINTESTINAL (GI) TRACT IS CLOSELY ASSOCIATED WITH CHRONIC INFLAMMATION, FOR WHICH ABNORMAL CELLULAR ALTERATIONS THAT ACCOMPANY CHRONIC INFLAMMATION SUCH AS OXIDATIVE STRESSES, GENE MUTATIONS, EPIGENETIC CHANGES, AND INFLAMMATORY CYTOKINES, ARE SHARED WITH CARCINOGENIC PROCESSES, WHICH FORMS A CRITICAL CROSS-LINK BETWEEN CHRONIC INFLAMMATION AND CARCINOGENESIS. TRANSFORMING GROWTH FACTOR (TGF)-BETA IS A MULTI-POTENT CYTOKINE THAT PLAYS AN IMPORTANT ROLE IN REGULATION OF CELL GROWTH, APOPTOSIS AND DIFFERENTIATION. MOST IMPORTANTLY, TGF-BETA IS A STRONG ANTI-INFLAMMATORY CYTOKINE THAT REGULATES THE DEVELOPMENT OF EFFECTOR CELLS. TGF-BETA HAS A SUPPRESSIVE EFFECT ON CARCINOGENESIS UNDER NORMAL CONDITIONS BY INHIBITING ABNORMAL CELL GROWTH, BUT ON THE OTHER HAND, MANY GI CANCERS ORIGINATE FROM UNCONTROLLED CELL GROWTH AND DIFFERENTIATION BY GENETIC LOSS OF TGF-BETA SIGNALING MOLECULES OR PERTURBATION OF TGF-BETA ADAPTORS. ONCE A TUMOR HAS DEVELOPED, TGF-BETA EXERTS A PROMOTING EFFECT ON THE TUMOR ITSELF AND STROMAL CELLS TO ENHANCE CELL GROWTH, ALTER THE RESPONSIVENESS OF TUMOR CELLS TO STIMULATE INVASION AND METASTASIS, AND INHIBITED IMMUNE SURVEILLANCE. THEREFORE, NOVEL DEVELOPMENT OF THERAPEUTIC AGENTS TO INHIBIT TGF-BETA-INDUCED PROGRESSION OF TUMOR AND TO RETAIN ITS GROWTH INHIBITORY ACTIVITIES, IN ADDITION TO ANTI-INFLAMMATORY ACTIONS, COULD BE USEFUL IN ONCOLOGY. IN THIS REVIEW, WE DISCUSS THE ROLE OF TGF-BETA IN INFLAMMATION AND CARCINOGENESIS OF THE GI TRACT RELATED TO ABNORMAL TGF-BETA SIGNALING. 2010 11 6100 26 THE EMERGING ROLE OF EPIGENETIC MODIFIERS IN REPAIR OF DNA DAMAGE ASSOCIATED WITH CHRONIC INFLAMMATORY DISEASES. AT SITES OF CHRONIC INFLAMMATION EPITHELIAL CELLS ARE EXPOSED TO HIGH LEVELS OF REACTIVE OXYGEN SPECIES (ROS), WHICH CAN CONTRIBUTE TO THE INITIATION AND DEVELOPMENT OF MANY DIFFERENT HUMAN CANCERS. ABERRANT EPIGENETIC ALTERATIONS THAT CAUSE TRANSCRIPTIONAL SILENCING OF TUMOR SUPPRESSOR GENES ARE ALSO IMPLICATED IN MANY DISEASES ASSOCIATED WITH INFLAMMATION, INCLUDING CANCER. HOWEVER, IT IS NOT CLEAR HOW ALTERED EPIGENETIC GENE SILENCING IS INITIATED DURING CHRONIC INFLAMMATION. THE HIGH LEVEL OF ROS AT SITES OF INFLAMMATION IS KNOWN TO INDUCE OXIDATIVE DNA DAMAGE IN SURROUNDING EPITHELIAL CELLS. FURTHERMORE, DNA DAMAGE IS KNOWN TO TRIGGER SEVERAL RESPONSES, INCLUDING RECRUITMENT OF DNA REPAIR PROTEINS, TRANSCRIPTIONAL REPRESSION, CHROMATIN MODIFICATIONS AND OTHER CELL SIGNALING EVENTS. RECRUITMENT OF EPIGENETIC MODIFIERS TO CHROMATIN IN RESPONSE TO DNA DAMAGE RESULTS IN TRANSIENT COVALENT MODIFICATIONS TO CHROMATIN SUCH AS HISTONE UBIQUITINATION, ACETYLATION AND METHYLATION AND DNA METHYLATION. DNA DAMAGE ALSO ALTERS NON-CODING RNA EXPRESSION. ALL OF THESE ALTERATIONS HAVE THE POTENTIAL TO ALTER GENE EXPRESSION AT SITES OF DAMAGE. TYPICALLY, THESE MODIFICATIONS AND GENE TRANSCRIPTION ARE RESTORED BACK TO NORMAL ONCE THE REPAIR OF THE DNA DAMAGE IS COMPLETED. HOWEVER, CHRONIC INFLAMMATION MAY INDUCE SUSTAINED DNA DAMAGE AND DNA DAMAGE RESPONSES THAT RESULT IN THESE TRANSIENT COVALENT CHROMATIN MODIFICATIONS BECOMING MITOTICALLY STABLE EPIGENETIC ALTERATIONS. UNDERSTANDING HOW EPIGENETIC ALTERATIONS ARE INITIATED DURING CHRONIC INFLAMMATION WILL ALLOW US TO DEVELOP PHARMACEUTICAL STRATEGIES TO PREVENT OR TREAT CHRONIC INFLAMMATION-INDUCED CANCER. THIS REVIEW WILL FOCUS ON TYPES OF DNA DAMAGE AND EPIGENETIC ALTERATIONS ASSOCIATED WITH CHRONIC INFLAMMATORY DISEASES, THE TYPES OF DNA DAMAGE AND TRANSIENT COVALENT CHROMATIN MODIFICATIONS INDUCED BY INFLAMMATION AND OXIDATIVE DNA DAMAGE AND HOW THESE MODIFICATIONS MAY RESULT IN EPIGENETIC ALTERATIONS. 2019 12 1232 33 CROSSTALK BETWEEN INFLAMMATORY SIGNALING AND METHYLATION IN CANCER. INFLAMMATION IS AN INTRICATE IMMUNE RESPONSE AGAINST INFECTION AND TISSUE DAMAGE. WHILE THE INITIAL IMMUNE RESPONSE IS IMPORTANT FOR PREVENTING TUMORIGENESIS, CHRONIC INFLAMMATION IS IMPLICATED IN CANCER PATHOGENESIS. IT HAS BEEN LINKED TO VARIOUS STAGES OF TUMOR DEVELOPMENT INCLUDING TRANSFORMATION, PROLIFERATION, ANGIOGENESIS, AND METASTASIS. IMMUNE CELLS, THROUGH THE PRODUCTION OF INFLAMMATORY MEDIATORS SUCH AS CYTOKINES, CHEMOKINES, TRANSFORMING GROWTH FACTORS, AND ADHESION MOLECULES CONTRIBUTE TO THE SURVIVAL, GROWTH, AND PROGRESSION OF THE TUMOR IN ITS MICROENVIRONMENT. THE ABERRANT EXPRESSION AND SECRETION OF PRO-INFLAMMATORY AND GROWTH FACTORS BY THE TUMOR CELLS RESULT IN THE RECRUITMENT OF IMMUNE CELLS, THUS CREATING A MUTUAL CROSSTALK. THE RECIPROCAL SIGNALING BETWEEN THE TUMOR CELLS AND THE IMMUNE CELLS CREATES AND MAINTAINS A SUCCESSFUL TUMOR NICHE. MANY INFLAMMATORY FACTORS ARE REGULATED BY EPIGENETIC MECHANISMS INCLUDING DNA METHYLATION AND HISTONE MODIFICATIONS. IN PARTICULAR, DNA AND HISTONE METHYLATION ARE CRUCIAL FORMS OF TRANSCRIPTIONAL REGULATION AND ABERRANT METHYLATION HAS BEEN ASSOCIATED WITH DEREGULATED GENE EXPRESSION IN ONCOGENESIS. SUCH DEREGULATIONS HAVE BEEN REPORTED IN BOTH SOLID TUMORS AND HEMATOLOGICAL MALIGNANCIES. WITH TECHNOLOGICAL ADVANCEMENTS TO STUDY GENOME-WIDE EPIGENETIC LANDSCAPES, IT IS NOW POSSIBLE TO IDENTIFY MOLECULAR MECHANISMS UNDERLYING ALTERED INFLAMMATORY PROFILES IN CANCER. IN THIS REVIEW, WE DISCUSS THE ROLE OF DNA AND HISTONE METHYLATION IN REGULATION OF INFLAMMATORY PATHWAYS IN HUMAN CANCERS AND REVIEW THE MERITS AND CHALLENGES OF TARGETING INFLAMMATORY MEDIATORS AS WELL AS EPIGENETIC REGULATORS IN CANCER. 2021 13 3659 28 INDUCTION OF EPIGENETIC ALTERATIONS BY CHRONIC INFLAMMATION AND ITS SIGNIFICANCE ON CARCINOGENESIS. CHRONIC INFLAMMATION IS DEEPLY INVOLVED IN DEVELOPMENT OF HUMAN CANCERS, SUCH AS GASTRIC AND LIVER CANCERS. INDUCTION OF CELL PROLIFERATION, PRODUCTION OF REACTIVE OXYGEN SPECIES, AND DIRECT STIMULATION OF EPITHELIAL CELLS BY INFLAMMATION-INDUCING FACTORS HAVE BEEN CONSIDERED AS MECHANISMS INVOLVED. INFLAMMATION-RELATED CANCERS ARE KNOWN FOR THEIR MULTIPLE OCCURRENCES, AND ABERRANT DNA METHYLATION IS KNOWN TO BE PRESENT EVEN IN NONCANCEROUS TISSUES. IMPORTANTLY, FOR SOME CANCERS, THE DEGREE OF ACCUMULATION HAS BEEN DEMONSTRATED TO BE CORRELATED WITH RISK OF DEVELOPING CANCERS. THIS INDICATES THAT INFLAMMATION INDUCES ABERRANT EPIGENETIC ALTERATIONS IN A TISSUE EARLY IN THE PROCESS OF CARCINOGENESIS, AND ACCUMULATION OF SUCH ALTERATIONS FORMS "AN EPIGENETIC FIELD FOR CANCERIZATION." THIS ALSO SUGGESTS THAT INHIBITION OF INDUCTION OF EPIGENETIC ALTERATIONS AND REMOVAL OF THE ACCUMULATED ALTERATIONS ARE NOVEL APPROACHES TO CANCER PREVENTION. DISTURBANCES IN CYTOKINE AND CHEMOKINE SIGNALS AND INDUCTION OF CELL PROLIFERATIONS ARE IMPORTANT MECHANISMS OF HOW INFLAMMATION INDUCES ABERRANT DNA METHYLATION. ABERRANT DNA METHYLATION IS INDUCED IN SPECIFIC GENES, AND GENE EXPRESSION LEVELS, THE PRESENCE OF RNA POLYMERASE II (ACTIVE OR STALLED), AND TRIMETHYLATION OF H3K4 ARE INVOLVED IN THE SPECIFICITY. EXPRESSION OF DNA METHYLTRANSFERASES (DNMTS) IS NOT NECESSARILY INDUCED BY INFLAMMATION, AND LOCAL IMBALANCE BETWEEN DNMTS AND FACTORS THAT PROTECT GENES FROM DNA METHYLATION SEEMS TO BE IMPORTANT. 2010 14 925 27 CHRONIC INFLAMMATION INDUCES A NOVEL EPIGENETIC PROGRAM THAT IS CONSERVED IN INTESTINAL ADENOMAS AND IN COLORECTAL CANCER. CHRONIC INFLAMMATION REPRESENTS A MAJOR RISK FACTOR FOR TUMOR FORMATION, BUT THE UNDERLYING MECHANISMS HAVE REMAINED LARGELY UNKNOWN. EPIGENETIC MECHANISMS CAN RECORD THE EFFECTS OF ENVIRONMENTAL CHALLENGES ON THE GENOME LEVEL AND COULD THEREFORE PLAY AN IMPORTANT ROLE IN THE PATHOGENESIS OF INFLAMMATION-ASSOCIATED TUMORS. USING SINGLE-BASE METHYLATION MAPS AND TRANSCRIPTOME ANALYSES OF A COLITIS-INDUCED MOUSE COLON CANCER MODEL, WE IDENTIFIED A NOVEL EPIGENETIC PROGRAM THAT IS CHARACTERIZED BY HYPERMETHYLATION OF DNA METHYLATION VALLEYS THAT ARE CHARACTERIZED BY LOW CPG DENSITY AND ACTIVE CHROMATIN MARKS. THIS PROGRAM IS CONSERVED AND FUNCTIONAL IN MOUSE INTESTINAL ADENOMAS AND RESULTS IN SILENCING OF ACTIVE INTESTINAL GENES THAT ARE INVOLVED IN GASTROINTESTINAL HOMEOSTASIS AND INJURY RESPONSE. FURTHER ANALYSES REVEAL THAT THE PROGRAM REPRESENTS A PROMINENT FEATURE OF HUMAN COLORECTAL CANCER AND CAN BE USED TO CORRECTLY CLASSIFY COLORECTAL CANCER SAMPLES WITH HIGH ACCURACY. TOGETHER, OUR RESULTS SHOW THAT INFLAMMATORY SIGNALS ESTABLISH A NOVEL EPIGENETIC PROGRAM THAT SILENCES A SPECIFIC SET OF GENES THAT CONTRIBUTE TO INFLAMMATION-INDUCED CELLULAR TRANSFORMATION. 2015 15 3672 15 INFLAMMATION AND CANCER: AN ANCIENT LINK WITH NOVEL POTENTIALS. INFECTION AND CHRONIC INFLAMMATION CONTRIBUTE TO ABOUT 1 IN 4 OF ALL CANCER CASES. MEDIATORS OF THE INFLAMMATORY RESPONSE, E.G., CYTOKINES, FREE RADICALS, PROSTAGLANDINS AND GROWTH FACTORS, CAN INDUCE GENETIC AND EPIGENETIC CHANGES INCLUDING POINT MUTATIONS IN TUMOR SUPPRESSOR GENES, DNA METHYLATION AND POST-TRANSLATIONAL MODIFICATIONS, CAUSING ALTERATIONS IN CRITICAL PATHWAYS RESPONSIBLE FOR MAINTAINING THE NORMAL CELLULAR HOMEOSTASIS AND LEADING TO THE DEVELOPMENT AND PROGRESSION OF CANCER. RECENT DISCOVERY OF AN INTERACTION BETWEEN MICRORNAS AND INNATE IMMUNITY DURING INFLAMMATION HAS FURTHER STRENGTHENED THE ASSOCIATION BETWEEN INFLAMMATION AND CANCER. 2007 16 6395 29 THE ROLE OF THE MEDIATORS OF INFLAMMATION IN CANCER DEVELOPMENT. EPIGENETIC DISORDERS SUCH AS POINT MUTATIONS IN CELLULAR TUMOR SUPPRESSOR GENES, DNA METHYLATION AND POST-TRANSLATIONAL MODIFICATIONS ARE NEEDED TO TRANSFORMATION OF NORMAL CELLS INTO CANCER CELLS. THESE EVENTS RESULT IN ALTERATIONS IN CRITICAL PATHWAYS RESPONSIBLE FOR MAINTAINING THE NORMAL CELLULAR HOMEOSTASIS, TRIGGERING TO AN INFLAMMATORY RESPONSE WHICH CAN LEAD THE DEVELOPMENT OF CANCER. THE INFLAMMATORY RESPONSE IS A UNIVERSAL DEFENSE MECHANISM ACTIVATED IN RESPONSE TO AN INJURY TISSUE, OF ANY NATURE, THAT INVOLVES BOTH INNATE AND ADAPTIVE IMMUNE RESPONSES, THROUGH THE COLLECTIVE ACTION OF A VARIETY OF SOLUBLE MEDIATORS. MANY INFLAMMATORY SIGNALING PATHWAYS ARE ACTIVATED IN SEVERAL TYPES OF CANCER, LINKING CHRONIC INFLAMMATION TO TUMORIGENESIS PROCESS. THUS, INFLAMMATORY RESPONSES PLAY DECISIVE ROLES AT DIFFERENT STAGES OF TUMOR DEVELOPMENT, INCLUDING INITIATION, PROMOTION, GROWTH, INVASION, AND METASTASIS, AFFECTING ALSO THE IMMUNE SURVEILLANCE. IMMUNE CELLS THAT INFILTRATE TUMORS ENGAGE IN AN EXTENSIVE AND DYNAMIC CROSSTALK WITH CANCER CELLS, AND SOME OF THE MOLECULAR EVENTS THAT MEDIATE THIS DIALOG HAVE BEEN REVEALED. A RANGE OF INFLAMMATION MEDIATORS, INCLUDING CYTOKINES, CHEMOKINES, FREE RADICALS, PROSTAGLANDINS, GROWTH AND TRANSCRIPTION FACTORS, MICRORNAS, AND ENZYMES AS, CYCLOOXYGENASE AND MATRIX METALLOPROTEINASE, COLLECTIVELY ACTS TO CREATE A FAVORABLE MICROENVIRONMENT FOR THE DEVELOPMENT OF TUMORS. IN THIS REVIEW ARE PRESENTED THE MAIN MEDIATORS OF THE INFLAMMATORY RESPONSE AND DISCUSSED THE LIKELY MECHANISMS THROUGH WHICH, THEY INTERACT WITH EACH OTHER TO CREATE A CONDITION FAVORABLE TO DEVELOPMENT OF CANCER. 2015 17 1173 29 CONTRIBUTION OF TLR SIGNALING TO THE PATHOGENESIS OF COLITIS-ASSOCIATED CANCER IN INFLAMMATORY BOWEL DISEASE. IN THE INTESTINE A BALANCE BETWEEN PROINFLAMMATORY AND REPAIR SIGNALS OF THE IMMUNE SYSTEM IS ESSENTIAL FOR THE MAINTENANCE OF INTESTINAL HOMEOSTASIS. THE INNATE IMMUNITY ENSURES A PRIMARY HOST RESPONSE TO MICROBIAL INVASION, WHICH INDUCES AN INFLAMMATORY PROCESS TO LOCALIZE THE INFECTION AND PREVENT SYSTEMIC DISSEMINATION OF PATHOGENS. THE KEY ELEMENTS OF THIS PROCESS ARE THE GERMLINE ENCODED PATTERN RECOGNITION RECEPTORS INCLUDING TOLL-LIKE RECEPTORS (TLRS). IF PATHOGENS CANNOT BE ELIMINATED, THEY MAY ELICIT CHRONIC INFLAMMATION, WHICH MAY BE PARTLY MEDIATED VIA TLRS. ADDITIONALLY, CHRONIC INFLAMMATION HAS LONG BEEN SUGGESTED TO TRIGGER TISSUE TUMOROUS TRANSFORMATION. INFLAMMATION, THE SEVENTH HALLMARK OF CANCER, MAY AFFECT ALL PHASES OF TUMOR DEVELOPMENT, AND EVADE THE IMMUNE SYSTEM. INFLAMMATION ACTS AS A CELLULAR STRESSOR AND MAY TRIGGER DNA DAMAGE OR GENETIC INSTABILITY. FURTHERMORE, CHRONIC INFLAMMATION CAN PROVOKE GENETIC MUTATIONS AND EPIGENETIC MECHANISMS THAT PROMOTE MALIGNANT CELL TRANSFORMATION. COLORECTAL CANCERS IN INFLAMMATORY BOWEL DISEASE PATIENTS ARE CONSIDERED TYPICAL EXAMPLES OF INFLAMMATION-RELATED CANCERS. ALTHOUGH DATA REGARDING THE ROLE OF TLRS IN THE PATHOMECHANISM OF CANCER-ASSOCIATED COLITIS ARE RATHER CONFLICTING, FUNCTIONALLY THESE MOLECULES CAN BE CLASSIFIED AS "LARGELY ANTITUMORIGENIC" AND "LARGELY PRO-TUMORIGENIC" WITH THE CAVEAT THAT THE UNDERLYING SIGNALING PATHWAYS ARE MAINLY CONTEXT (I.E., ORGAN-, TISSUE-, CELL-) AND LIGAND-DEPENDENT. 2014 18 2854 26 FROM HEPATITIS TO HEPATOCELLULAR CARCINOMA: A PROPOSED MODEL FOR CROSS-TALK BETWEEN INFLAMMATION AND EPIGENETIC MECHANISMS. INFLAMMATION REPRESENTS THE BODY'S NATURAL RESPONSE TO TISSUE DAMAGE; HOWEVER, CHRONIC INFLAMMATION MAY ACTIVATE CELL PROLIFERATION AND INDUCE DEREGULATION OF CELL DEATH IN AFFECTED TISSUES. CHRONIC INFLAMMATION IS AN IMPORTANT FACTOR IN THE DEVELOPMENT OF HEPATOCELLULAR CARCINOMA (HCC), ALTHOUGH THE PRECISE UNDERLYING MECHANISM REMAINS UNKNOWN. EPIGENETIC EVENTS, WHICH ARE CONSIDERED KEY MECHANISMS IN THE REGULATION OF GENE ACTIVITY STATES, ARE ALSO COMMONLY DEREGULATED IN HCC. HERE, WE REVIEW THE EVIDENCE THAT CHRONIC INFLAMMATION MIGHT DEREGULATE EPIGENETIC PROCESSES, THUS PROMOTING ONCOGENIC TRANSFORMATION, AND WE PROPOSE A WORKING HYPOTHESIS THAT EPIGENETIC DEREGULATION IS AN UNDERLYING MECHANISM BY WHICH INFLAMMATION MIGHT PROMOTE HCC DEVELOPMENT. IN THIS SCENARIO, DIFFERENT COMPONENTS OF THE INFLAMMATORY RESPONSE MIGHT DIRECTLY AND INDIRECTLY INDUCE CHANGES IN EPIGENETIC MACHINERIES ('EPIGENETIC SWITCH'), INCLUDING THOSE INVOLVED IN SETTING AND PROPAGATING NORMAL PATTERNS OF DNA METHYLATION, HISTONE MODIFICATIONS AND NON-CODING RNAS IN HEPATOCYTES. WE DISCUSS THE POSSIBILITY THAT SELF-REINFORCING CROSS-TALK BETWEEN INFLAMMATION AND EPIGENETIC MECHANISMS MIGHT AMPLIFY INFLAMMATORY SIGNALS AND MAINTAIN A CHRONIC STATE OF INFLAMMATION CULMINATING IN CANCER DEVELOPMENT. THE POTENTIAL ROLE OF INFLAMMATION-EPIGENOME INTERACTIONS IN THE EMERGENCE AND MAINTENANCE OF CANCER STEM CELLS IS ALSO DISCUSSED. 2012 19 2578 23 EPIGENETICS OF INFLAMMATORY BOWEL DISEASES. INFLAMMATORY BOWEL DISEASES ARE MULTIFACTORIAL, CHRONIC, CONTINUOUS, RELAPSING, AND IMMUNE-MEDIATED DISEASES OF THE GASTROINTESTINAL TRACT. IT HAS BEEN BELIEVED THAT MECHANISMS UNDERLYING INFLAMMATORY BOWEL DISEASES INCLUDE GENETIC PREDISPOSITION, ENVIRONMENTAL FACTORS, AND ALTERED IMMUNE RESPONSE TO THE GUT MICROBIOME. THE EPIGENETIC MODULATION TAKES PLACE VIA CHROMATIN MODIFICATIONS, INCLUDING PHOSPHORYLATION, ACETYLATION, METHYLATION, SUMOYLATION, AND UBIQUITINATION. THE METHYLATION LEVELS OF COLONIC TISSUE WERE FOUND WELL CORRELATED TO BLOOD SAMPLES IN INFLAMMATORY BOWEL DISEASES. MOREOVER, THE METHYLATION LEVEL OF SPECIFIC GENES WAS DIFFERENT BETWEEN CROHN'S DISEASE AND ULCERATIVE COLITIS. IT HAS BEEN SHOWN THAT THE ENZYMES AFFECTING HISTONE MODIFICATIONS LIKE HISTONE DEACETYLASES AND HISTONE ACETYLTRANSFERASES DO NOT ACT SOLELY ON HISTONES BUT ALSO AFFECT THE ACETYLATION OF MANY PROTEINS SUCH AS P53 AND STAT3. IT HAS BEEN ALREADY SHOWN THAT A NONSELECTIVE HISTONE DEACETYLASE INHIBITOR, VORINOSTAT (SAHA), WHICH IS CURRENTLY BEING USED IN SEVERAL CANCER TREATMENTS, SHOWED ANTI-INFLAMMATORY ACTIVITIES IN MOUSE MODELS. AMONG EPIGENETIC ALTERATIONS, LONG NON-CODING RNAS AND MICRORNAS PLAY SIGNIFICANT ROLES IN T-CELL MATURATION, DIFFERENTIATION, ACTIVATION, AND SENILITY. THE LONG NON-CODING RNA AND MICRORNA EXPRESSION PROFILES CAN PERFECTLY SEPARATE INFLAMMATORY BOWEL DISEASE PATIENTS FROM HEALTHY CONTROLS AND ARE REMARKED AS BIOMARKERS OF INFLAMMATORY BOWEL DISEASES. OVERALL, MANY STUDIES HAVE SHOWN THAT EPIGENETIC INHIBITORS CAN TARGET SIGNIFICANT SIGNAL PATHWAYS IN THE PATHOGENESIS OF INFLAMMATORY BOWEL DISEASES, AND THE IMPACT OF EPIGENETIC INHIBITORS IS BEING STUDIED IN CLINICAL TRIALS. IN CONCLUSION, EXPLORING MORE EPIGENETIC PATHWAYS REGARDING INFLAMMATORY BOWEL DISEASE PATHOGENESIS WILL HELP US TO DISCOVER THERAPEUTIC TARGETS AND NEW DRUGS AND AGENTS TARGETING MIRNAS IN INFLAMMATORY BOWEL DISEASES. IN GENERAL, DISCOVERING EPIGENETIC TARGETS COULD IMPROVE THE DIAGNOSIS AND TREATMENT OF INFLAMMATORY BOWEL DISEASES. 2023 20 2601 36 EPIGENETICS, DNA ORGANIZATION, AND INFLAMMATORY BOWEL DISEASE. INFLAMMATORY BOWEL DISEASES (IBDS) ARE CHRONIC INFLAMMATORY DISORDERS AFFECTING THE GASTROINTESTINAL TRACT. THE INCIDENCE OF IBD IS INCREASING, WITH MORE CASES OCCURRING IN DEVELOPED COUNTRIES. MULTIPLE FACTORS SUCH AS GENETICS, ENVIRONMENTAL CHANGES, GUT MICROBIOTA, AND IMMUNE ABNORMALITIES HAVE BEEN ASSOCIATED WITH DEVELOPMENT OF IBD. IN RECENT YEARS, IT HAS BECOME INCREASINGLY APPARENT THAT EPIGENETIC MODIFICATIONS OF CHROMATIN AND THE MANNER IN WHICH CHROMATIN IS ORGANIZED IN THE NUCLEUS ARE ADDITIONALLY IMPORTANT ELEMENTS THAT CAN INFLUENCE RESPONSES INDUCED BY THE FACTORS DESCRIBED ABOVE, AND MAY THEREFORE CONTRIBUTE TO THE ONSET AND PATHOGENESIS OF IBD. EPIGENETICS AND CHROMATIN ORGANIZATION REGULATE DIVERSE FUNCTIONS THAT INCLUDE MAINTENANCE OF HOMEOSTASIS IN THE INTESTINAL EPITHELIUM, THE DEVELOPMENT AND DIFFERENTIATION OF IMMUNE CELLS, AND MODULATION OF RESPONSES GENERATED BY THE IMMUNE SYSTEM TO DEFEND AGAINST POTENTIAL PATHOGENS. FURTHERMORE, CHANGES IN EPIGENETIC CHROMATIN MARKS AND IN CHROMATIN ORGANIZATION HAVE NOW BEEN LINKED TO DIFFERENTIAL GENE EXPRESSION IN IBD PATIENT CELLS. ALTHOUGH DIRECT EVIDENCE FOR A ROLE OF HISTONE MODIFICATIONS IN IBD IS CURRENTLY VERY LIMITED, IN THIS REVIEW, WE SUMMARIZE THE LINKS BETWEEN VARIOUS EPIGENETIC MODIFICATIONS, THE PROTEINS THAT CATALYZE OR RECOGNIZE THESE MODIFICATIONS, AND THE DEVELOPMENT OR PROGRESSION OF IBD IN HUMAN AND EXPERIMENTAL IBD. WE ALSO DISCUSS HOW EPIGENETICS INFLUENCE THE ORGANIZATION OF DNA CONTACTS TO REGULATE GENE EXPRESSION AND THE IMPLICATIONS THIS MAY HAVE FOR DIAGNOSING AND TREATING IBD. 2019