1 4261 134 MGMT-METHYLATION IN NON-NEOPLASTIC DISEASES OF THE CENTRAL NERVOUS SYSTEM. QUANTIFYING O(6)-METHYLGUANINE-DNA METHYLTRANSFERASE (MGMT) PROMOTER METHYLATION PLAYS AN ESSENTIAL ROLE IN ASSESSING THE POTENTIAL EFFICACY OF ALKYLATING AGENTS IN THE CHEMOTHERAPY OF MALIGNANT GLIOMAS. MGMT PROMOTER METHYLATION IS CONSIDERED TO BE A CHARACTERISTIC OF SUBGROUPS OF CERTAIN MALIGNANCIES BUT HAS ALSO BEEN DESCRIBED IN VARIOUS PERIPHERAL INFLAMMATORY DISEASES. HOWEVER, MGMT PROMOTER METHYLATION LEVELS HAVE NOT YET BEEN INVESTIGATED IN NON-NEOPLASTIC BRAIN DISEASES. THIS STUDY DEMONSTRATES FOR THE FIRST TIME THAT ONE CAN INDEED DETECT SLIGHTLY ENHANCED MGMT PROMOTER METHYLATION IN INDIVIDUAL CASES OF INFLAMMATORY DEMYELINATING CNS DISEASES SUCH AS MULTIPLE SCLEROSIS AND PROGRESSIVE MULTIFOCAL LEUCENCEPHALOPATHY (PML), AS WELL AS IN OTHER DEMYELINATING DISEASES SUCH AS CENTRAL PONTINE AND EXPTRAPONTINE MYELINOLYSIS, AND DISEASES WITH MYELIN DAMAGE SUCH AS WALLERIAN DEGENERATION. IN THIS CONTEXT, WE IDENTIFIED A REDUCTION IN THE EXPRESSION OF THE DEMETHYLASE TET1 AS A POSSIBLE CAUSE FOR THE ENHANCED MGMT PROMOTER METHYLATION. HENCE, WE SHOW FOR THE FIRST TIME THAT MGMT HYPERMETHYLATION OCCURS IN CHRONIC DISEASES THAT ARE NOT STRICTLY ASSOCIATED TO DISTINCT PATHOGENS, ONCOGENIC VIRUSES OR NEOPLASMS BUT THAT LEAD TO DAMAGE OF THE MYELIN SHEATH IN VARIOUS WAYS. WHILE THIS GIVES NEW INSIGHTS INTO EPIGENETIC AND PATHOPHYSIOLOGICAL PROCESSES INVOLVED IN DE- AND REMYELINATION, WHICH MIGHT OFFER NEW THERAPEUTIC OPPORTUNITIES FOR DEMYELINATING DISEASES IN THE FUTURE, IT ALSO REDUCES THE SPECIFICITY OF MGMT HYPERMETHYLATION AS A TUMOR BIOMARKER. 2021 2 1611 43 DNA METHYLATION: A NEW PLAYER IN MULTIPLE SCLEROSIS. MULTIPLE SCLEROSIS (MS) IS A NEUROLOGICAL AND CHRONIC INFLAMMATORY DISEASE THAT IS MEDIATED BY DEMYELINATION AND AXONAL DEGENERATION IN THE CENTRAL NERVOUS SYSTEM (CNS). STUDIES HAVE SHOWN THAT IMMUNE SYSTEM COMPONENTS SUCH AS CD4+, CD8+, CD44+ T CELLS, B LYMPHATIC CELLS, AND INFLAMMATORY CYTOKINES PLAY A CRITICAL ROLE IN INFLAMMATORY PROCESSES AND MYELIN DAMAGE ASSOCIATED WITH MS. NEVERTHELESS, THE PATHOGENESIS OF MS REMAINS POORLY DEFINED. DNA METHYLATION, A SIGNIFICANT EPIGENETIC MODIFICATION, IS REPORTED TO BE EXTENSIVELY INVOLVED IN MS PATHOGENESIS THROUGH THE REGULATION OF GENE EXPRESSION. THIS REVIEW FOCUSES ON DNA METHYLATION INVOLVED IN MS PATHOGENESIS. EVIDENCE SHOWED THE HYPERMETHYLATION OF HUMAN LEUKOCYTE ANTIGEN-DRB1 (HLA-DRB1) IN CD4+ T CELLS, THE GENOME-WIDE DNA METHYLATION IN CD8+ T CELLS, THE HYPERMETHYLATION OF INTERLEUKIN-4 (IL-4)/FORKHEAD WINGED HELIX TRANSCRIPTION FACTOR 3 (FOXP3), AND THE DEMETHYLATION OF INTERFERON-GAMMA (IFN-GAMMA)/IL-17A IN CD44+ ENCEPHALITOGENIC T CELLS. STUDIES ALSO SHOWED THE HYPERMETHYLATION OF SH2-CONTAINING PROTEIN TYROSINE PHOSPHATASE-1 (SHP-1) IN PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMCS) AND METHYLATED CHANGES OF GENES REGULATING OLIGODENDROCYTE AND NEURONAL FUNCTION IN NORMAL-APPEARING WHITE MATTER. CLARIFYING THE MECHANISM OF ABERRANT METHYLATION ON MS MAY EXPLAIN PART OF THE PATHOLOGY AND WILL LEAD TO THE DEVELOPMENT OF A NEW THERAPEUTIC TARGET FOR THE TREATMENT OF MS IN THE FUTURE. 2017 3 6136 42 THE EPIGENETICS OF MULTIPLE SCLEROSIS AND OTHER RELATED DISORDERS. MULTIPLE SCLEROSIS (MS) IS A DEMYELINATING DISEASE CHARACTERIZED BY CHRONIC INFLAMMATION OF THE CENTRAL NERVOUS SYSTEM (CNS) GRAY AND WHITE MATTER. ALTHOUGH THE CAUSE OF MS IS UNKNOWN, IT IS WIDELY APPRECIATED THAT INNATE AND ADAPTIVE IMMUNE PROCESSES CONTRIBUTE TO ITS PATHOGENESIS. THESE INCLUDE MICROGLIA/MACROPHAGE ACTIVATION, PRO-INFLAMMATORY T-CELL (TH1) RESPONSES AND HUMORAL RESPONSES. ADDITIONALLY, THERE IS EVIDENCE INDICATING THAT MS HAS A NEURODEGENERATIVE COMPONENT SINCE NEURONAL AND AXONAL LOSS OCCURS EVEN IN THE ABSENCE OF OVERT INFLAMMATION. THESE ASPECTS ALSO FORM THE RATIONALE FOR CLINICAL MANAGEMENT OF THE DISEASE. HOWEVER, THE CURRENTLY AVAILABLE THERAPIES TO CONTROL THE DISEASE ARE ONLY PARTIALLY EFFECTIVE AT BEST INDICATING THAT MORE EFFECTIVE THERAPEUTIC SOLUTIONS ARE URGENTLY NEEDED. IT IS APPRECIATED THAT IN THE IMMUNE-DRIVEN AND NEURODEGENERATIVE PROCESSES MS-SPECIFIC DEREGULATION OF GENE EXPRESSIONS AND RESULTING PROTEIN DYSFUNCTION ARE THOUGHT TO PLAY A CENTRAL ROLE. THESE DEVIATIONS IN GENE EXPRESSION PATTERNS CONTRIBUTE TO THE INFLAMMATORY RESPONSE IN THE CNS, AND TO NEURONAL OR AXONAL LOSS. EPIGENETIC MECHANISMS CONTROL TRANSCRIPTION OF MOST, IF NOT ALL GENES, IN NUCLEATED CELLS INCLUDING CELLS OF THE CNS AND IN HAEMATOPOIETIC CELLS. MS-SPECIFIC ALTERATIONS IN EPIGENETIC REGULATION OF GENE EXPRESSION MAY THEREFORE LIE AT THE HEART OF THE DEREGULATION OF GENE EXPRESSION IN MS. AS SUCH, EPIGENETIC MECHANISMS MOST LIKELY PLAY AN IMPORTANT ROLE IN DISEASE PATHOGENESIS. IN THIS REVIEW WE DISCUSS A ROLE FOR MS-SPECIFIC DEREGULATION OF EPIGENETIC FEATURES THAT CONTROL GENE EXPRESSION IN THE CNS AND IN THE PERIPHERY. FURTHERMORE, WE DISCUSS THE APPLICATION OF SMALL MOLECULE INHIBITORS THAT TARGET THE EPIGENETIC MACHINERY TO AMELIORATE DISEASE IN EXPERIMENTAL ANIMAL MODELS, INDICATING THAT SUCH APPROACHES MAY BE APPLICABLE TO MS PATIENTS. 2014 4 1542 33 DNA METHYLATION IN HAEMATOLOGICAL MALIGNANCIES: THE ROLE OF DECITABINE. NORMAL CELL DEVELOPMENT AND FUNCTION IS DEPENDENT UPON CONTROLLED GENE EXPRESSION. DNA METHYLATION IS AN EPIGENETIC MODIFICATION THAT CAN PLAY AN IMPORTANT ROLE IN THE CONTROL OF GENE EXPRESSION. DNA METHYLATION AT CYTOSINE RESIDUES IN GENE PROMOTER CPG SEQUENCES IS KNOWN TO INHIBIT GENE TRANSCRIPTION. INAPPROPRIATE INHIBITION OF THE TRANSCRIPTION OF TUMOUR SUPPRESSOR GENES, GENES THAT INHIBIT ANGIOGENESIS AND METASTASIS AND GENES INVOLVED IN DNA REPAIR BY UNCONTROLLED METHYLATION, CAN LEAD TO UNREGULATED GROWTH AND PROLIFERATION OF A CELL AND CARCINOGENESIS. PROMOTER HYPERMETHYLATION AFFECTING THE P16 GENE, RESULTING IN GENE SILENCING, HAS BEEN SHOWN TO OCCUR IN MANY HUMAN SOLID TUMOURS AND A 'HYPERMETHYLATION PROFILE' IN SOME LEUKAEMIAS HAS BEEN DEFINED. THE MOLECULAR MECHANISMS BY WHICH ABERRANT DNA METHYLATION TAKES PLACE DURING CARCINOGENESIS ARE STILL NOT CLEAR. HOWEVER, THE LARGE NUMBER OF TARGET GENES (INVOLVED IN TUMORIGENESIS) THAT ARE SILENCED BY ABERRANT METHYLATION SUGGESTS THAT INHIBITION OF THIS PROCESS MAY HAVE POTENTIAL AS CANCER THERAPY. DECITABINE (NSC-127716, DACOGEN; SUPERGEN) IS A POTENT AND SPECIFIC HYPOMETHYLATING AGENT AND AN INHIBITOR OF THE DNA METHYLTRANSFERASE ACTIVITY THAT MEDIATES DNA METHYLATION. DECITABINE HAS BEEN SHOWN TO HAVE A BROAD RANGE OF ANTINEOPLASTIC ACTIVITY IN PRECLINICAL STUDIES. THIS AGENT HAS EXHIBITED SIGNIFICANT ACTIVITY IN THE TREATMENT OF PATIENTS WITH MYELODYSPLASTIC SYNDROME, CHRONIC MYELOID LEUKAEMIA AND ACUTE MYELOID LEUKAEMIA, ALTHOUGH CLINICAL PHASE I AND II STUDIES WITH SOLID TUMOURS HAVE NOT BEEN VERY PROMISING. PHASE II AND III STUDIES ARE CURRENTLY ONGOING TO EVALUATE DECITABINE, BOTH ALONE AND IN COMBINATION, IN VARIOUS STAGES OF THESE HAEMATOLOGICAL MALIGNANCIES. 2003 5 1508 31 DNA METHYLATION AND MRNA AND MICRORNA EXPRESSION OF SLE CD4+ T CELLS CORRELATE WITH DISEASE PHENOTYPE. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IS AN AUTOIMMUNE DISEASE WELL KNOWN FOR ITS CLINICAL HETEROGENEITY, AND ITS ETIOLOGY SECONDARY TO A CROSS-TALK INVOLVING GENETIC PREDISPOSITION AND ENVIRONMENTAL STIMULI. ALTHOUGH GENOME-WIDE ANALYSIS HAS CONTRIBUTED GREATLY TO OUR UNDERSTANDING OF THE GENETIC BASIS OF SLE, THERE IS INCREASING EVIDENCE FOR A ROLE OF EPIGENETICS. INDEED, RECENT DATA HAVE DEMONSTRATED THAT IN PATIENTS WITH SLE, THERE ARE STRIKING ALTERATIONS OF DNA METHYLATION, HISTONE MODIFICATIONS, AND DEREGULATED MICRORNA EXPRESSION, THE SUM OF WHICH CONTRIBUTE TO OVER-EXPRESSION OF SELECT AUTOIMMUNE-RELATED GENES AND LOSS OF TOLERANCE. TO ADDRESS THIS ISSUE AT THE LEVEL OF CLINICAL PHENOTYPE, WE PERFORMED DNA METHYLATION, MRNA AND MICRORNA EXPRESSION SCREENING USING HIGH-THROUGHPUT SEQUENCING OF PURIFIED CD4+ T CELLS FROM PATIENTS WITH SLE, COMPARED TO AGE AND SEX MATCHED CONTROLS. IN PARTICULAR, WE STUDIED 42 PATIENTS WITH SLE AND DIVIDED THIS GROUP INTO THREE CLINICAL PHENOTYPES: A) THE PRESENCE OF SKIN LESIONS WITHOUT SIGNS OF SYSTEMIC PATHOLOGY; B) SKIN LESIONS BUT ALSO CHRONIC RENAL PATHOLOGY; AND C) SKIN LESIONS, CHRONIC RENAL PATHOLOGY AND POLYARTICULAR DISEASE. INTERESTINGLY, AND AS EXPECTED, SEQUENCING DATA REVEALED CHANGES IN DNA METHYLATION IN SLE COMPARED TO CONTROLS. HOWEVER, AND MORE IMPORTANTLY, ALTHOUGH THERE WERE COMMON METHYLATION CHANGES FOUND IN ALL GROUPS OF SLE COMPARED TO CONTROLS, THERE WAS SPECIFIC DNA METHYLATION CHANGES THAT CORRELATED WITH CLINICAL PHENOTYPE. THESE INCLUDED CHANGES IN THE NOVEL KEY TARGET GENES NLRP2, CD300LB AND S1PR3, AS WELL AS CHANGES IN THE CRITICAL PATHWAYS, INCLUDING THE ADHERENS JUNCTION AND LEUKOCYTE TRANSENDOTHELIAL MIGRATION. WE ALSO NOTED THAT A SIGNIFICANT PROPORTION OF GENES UNDERGOING DNA METHYLATION CHANGES WERE INVERSELY CORRELATED WITH GENE EXPRESSION AND THAT MIRNA SCREENING REVEALED THE EXISTENCE OF SUBSETS WITH CHANGES IN EXPRESSION. INTEGRATED ANALYSIS OF THIS DATA HIGHLIGHTS SPECIFIC SETS OF MIRNAS CONTROLLED BY DNA METHYLATION, AND GENES THAT ARE ALTERED BY METHYLATION AND TARGETED BY MIRNAS. IN CONCLUSION, OUR FINDINGS SUGGEST SELECT EPIGENETIC MECHANISMS THAT CONTRIBUTE TO CLINICAL PHENOTYPES AND FURTHER SHED LIGHT ON A NEW VENUE FOR BASIC SLE RESEARCH. 2014 6 6896 27 [TARGETED EPIGENETIC THERAPY OF CANCER. ACHIEVEMENTS AND PERSPECTIVES]. IN THIS REVIEW, WE PROVIDE AN OVERVIEW OF THE PHYSIOLOGICAL AND PATHOPHYSIOLOGICAL EPIGENETIC CHANGES OF NORMAL CELLS AND CANCER CELLS, AND EMPHASIZE THE ACHIEVEMENTS AND THE PERSPECTIVES OF CANCER EPIGENETIC THERAPY. CANCER EPIGENETIC ALTERATIONS CORRESPOND FOREMOST TO HYPERMETHYLATION OF TUMOR SUPPRESSOR GENES PROMOTORS, GLOBAL DNA HYPOMETHYLATION, AND OVEREXPRESSION AND ACTIVITY OF HISTONE DEACETYLASES. THE PURPOSE OF EPIGENETIC THERAPY IS TO REVERT THE EPIGENETIC ALTERATIONS IN CANCER CELLS AND OBTAIN THE "NORMAL EPIGENOME" RESTORATION. EPIGENETIC TARGETS IN CANCER THERAPY HAVE FOCUSED ON HDACS AND DNMTS INHIBITION. THE AZACITIDINE AND THE DECITABINE, THE VORINOSTAT AND THE ROMIDEPSIN WERE APPROVED BY US-FDA FOR TREATMENT OF MYELODYSPLASTIC SYNDROME, AND CUTANEOUS T-CELL LYMPHOMA, RESPECTIVELY. EPIGENETIC AND EPIGENOMIC CHANGES IN SINGLE OR MULTIPLE GENES HAVE SHOWED POTENTIAL IMPACT IN CANCER AS EARLY DETECTION, PROGNOSIS AND PREDICTIVE MARKS. THE EPIGENETIC REVOLUTION HAS ARRIVED FOR BIOLOGY. THE SIGNIFICANT PROGRESS IN EPIGENETIC STUDIES HAVE ALLOWED US, TO UNDERSTAND NEW LOOKS IN THE PHYSIOLOGY AND PATHOPHYSIOLOGY OF EMBRYONIC DEVELOPMENT, CANCER AND OTHER CHRONIC DISEASES. SPECIFIC MOLECULAR EPIGENETIC ALTERATIONS IN DIFFERENT CANCER TYPES, GIVE US NEW STRATEGIES TO DESIGN IMPROVED CANCER THERAPY. THE CHALLENGE FOR EPIGENETIC INVESTIGATORS IS DESIGN MORE SPECIFIC EPIDRUGS WITH LESSER SIDE EFFECTS. 2012 7 2033 30 EPIGENETIC CHANGES IN SOLID AND HEMATOPOIETIC TUMORS. THERE ARE THREE CONNECTED MOLECULAR MECHANISMS OF EPIGENETIC CELLULAR MEMORY IN MAMMALIAN CELLS: DNA METHYLATION, HISTONE MODIFICATIONS, AND RNA INTERFERENCE. THE FIRST TWO HAVE NOW BEEN FIRMLY LINKED TO NEOPLASTIC TRANSFORMATION. HYPERMETHYLATION OF CPG-RICH PROMOTERS TRIGGERS LOCAL HISTONE CODE MODIFICATIONS RESULTING IN A CELLULAR CAMOUFLAGE MECHANISM THAT SEQUESTERS GENE PROMOTERS AWAY FROM TRANSCRIPTION FACTORS AND RESULTS IN STABLE SILENCING. THIS NORMALLY RESTRICTED MECHANISM IS UBIQUITOUSLY USED IN CANCER TO SILENCE HUNDREDS OF GENES, AMONG WHICH SOME CRITICALLY CONTRIBUTE TO THE NEOPLASTIC PHENOTYPE. VIRTUALLY EVERY PATHWAY IMPORTANT TO CANCER FORMATION IS AFFECTED BY THIS PROCESS. METHYLATION PROFILING OF HUMAN CANCERS REVEALS TISSUE-SPECIFIC EPIGENETIC SIGNATURES, AS WELL AS TUMOR-SPECIFIC SIGNATURES, REFLECTING IN PARTICULAR THE PRESENCE OF EPIGENETIC INSTABILITY IN A SUBSET OF CANCERS AFFECTED BY THE CPG ISLAND METHYLATOR PHENOTYPE. GENERALLY, METHYLATION PATTERNS CAN BE TRACED TO A TISSUE-SPECIFIC, PROLIFERATION-DEPENDENT ACCUMULATION OF ABERRANT PROMOTER METHYLATION IN AGING TISSUES, A PROCESS THAT CAN BE ACCELERATED BY CHRONIC INFLAMMATION AND LESS WELL-DEFINED MECHANISMS INCLUDING, POSSIBLY, DIET AND GENETIC PREDISPOSITION. THE EPIGENETIC MACHINERY CAN ALSO BE ALTERED IN CANCER BY SPECIFIC LESIONS IN EPIGENETIC EFFECTOR GENES, OR BY ABERRANT RECRUITMENT OF THESE GENES BY MUTANT TRANSCRIPTION FACTORS AND COACTIVATORS. EPIGENETIC PATTERNS ARE PROVING CLINICALLY USEFUL IN HUMAN ONCOLOGY VIA RISK ASSESSMENT, EARLY DETECTION, AND PROGNOSTIC CLASSIFICATION. PHARMACOLOGIC MANIPULATION OF THESE PATTERNS-EPIGENETIC THERAPY-IS ALSO POISED TO CHANGE THE WAY WE TREAT CANCER IN THE CLINIC. 2005 8 3659 34 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 9 2025 33 EPIGENETIC CHANGES DURING DISEASE PROGRESSION IN A MURINE MODEL OF HUMAN CHRONIC LYMPHOCYTIC LEUKEMIA. EPIGENETIC ALTERATIONS, INCLUDING GAIN OR LOSS OF DNA METHYLATION, ARE A HALLMARK OF NEARLY EVERY MALIGNANCY. CHANGES IN DNA METHYLATION CAN IMPACT EXPRESSION OF CANCER-RELATED GENES INCLUDING APOPTOSIS REGULATORS AND TUMOR SUPPRESSORS. BECAUSE SUCH EPIGENETIC CHANGES ARE REVERSIBLE, THEY ARE BEING AGGRESSIVELY INVESTIGATED AS POTENTIAL THERAPEUTIC TARGETS. HERE WE USE THE EMU-TCL1 TRANSGENIC MOUSE MODEL OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) TO DETERMINE THE TIMING AND PATTERNS OF ABERRANT DNA METHYLATION, AND TO INVESTIGATE THE MECHANISMS THAT LEAD TO ABERRANT DNA METHYLATION. WE SHOW THAT CLL CELLS FROM EMU-TCL1 MICE AT VARIOUS STAGES RECAPITULATE EPIGENETIC ALTERATIONS SEEN IN HUMAN CLL. ABERRANT METHYLATION OF PROMOTER SEQUENCES IS OBSERVED AS EARLY AS 3 MONTHS OF AGE IN THESE ANIMALS, WELL BEFORE DISEASE ONSET. ABNORMALLY METHYLATED PROMOTER REGIONS INCLUDE BINDING SITES FOR THE TRANSCRIPTION FACTOR FOXD3. WE SHOW THAT LOSS OF FOXD3 EXPRESSION DUE TO AN NF-KAPPAB P50/P50:HDAC1 REPRESSOR COMPLEX OCCURS IN TCL1-POSITIVE B CELLS BEFORE METHYLATION. THEREFORE, SPECIFIC TRANSCRIPTIONAL REPRESSION IS AN EARLY EVENT LEADING TO EPIGENETIC SILENCING OF TARGET GENES IN MURINE AND HUMAN CLL. THESE RESULTS PROVIDE STRONG RATIONALE FOR THE DEVELOPMENT OF STRATEGIES TO TARGET NF-KAPPAB COMPONENTS IN CLL AND POTENTIALLY OTHER B-CELL MALIGNANCIES. 2009 10 2909 31 GENE EXPRESSION PROFILING IN FIBROMYALGIA INDICATES AN AUTOIMMUNE ORIGIN OF THE DISEASE AND OPENS NEW AVENUES FOR TARGETED THERAPY. FIBROMYALGIA IS A CHRONIC DISORDER CHARACTERIZED BY WIDESPREAD PAIN AND BY SEVERAL NON-PAIN SYMPTOMS. AUTOIMMUNITY, SMALL FIBER NEUROPATHY AND NEUROINFLAMMATION HAVE BEEN SUGGESTED TO BE INVOLVED IN THE PATHOGENESIS OF THE DISEASE. WE HAVE INVESTIGATED THE GENE EXPRESSION PROFILE IN PERIPHERAL BLOOD MONONUCLEAR CELLS OBTAINED FROM TEN PATIENTS AND TEN HEALTHY SUBJECTS. OF THE 545,500 TRANSCRIPTS ANALYZED, 1673 RESULTED MODULATED IN FIBROMYALGIC PATIENTS. THE MAJORITY OF THESE GENES ARE INVOLVED IN BIOLOGICAL PROCESSES AND PATHWAYS LINKED TO THE CLINICAL MANIFESTATIONS OF THE DISEASE. MOREOVER, GENES INVOLVED IN IMMUNOLOGICAL PATHWAYS CONNECTED TO INTERLEUKIN-17 AND TO TYPE I INTERFERON SIGNATURES WERE ALSO MODULATED, SUGGESTING THAT AUTOIMMUNITY PLAYS A ROLE IN THE DISEASE. WE THEN AIMED AT IDENTIFYING DIFFERENTIALLY EXPRESSED LONG NON-CODING RNAS (LNCRNAS) FUNCTIONALLY CONNECTED TO MODULATED GENES BOTH DIRECTLY AND VIA MICRORNA TARGETING. ONLY TWO LNCRNAS OF THE 298 FOUND MODULATED IN PATIENTS, WERE ABLE TO TARGET THE MOST HIGHLY CONNECTED GENES IN THE FIBROMYALGIA INTERACTOME, SUGGESTING THEIR INVOLVEMENT IN CRUCIAL GENE REGULATION. OUR GENE EXPRESSION DATA WERE CONFIRMED BY REAL TIME PCR, BY AUTOANTIBODY TESTING, DETECTION OF SOLUBLE MEDIATORS AND TH-17 POLARIZATION IN A VALIDATION COHORT OF 50 PATIENTS. OUR RESULTS INDICATE THAT GENETIC AND EPIGENETIC MECHANISMS AS WELL AS AUTOIMMUNITY PLAY A PIVOTAL ROLE IN THE PATHOGENESIS OF FIBROMYALGIA. 2020 11 6771 31 [ACQUIRED DISORDERS AND EPIGENETICS]. EPIGENETIC MODIFICATIONS, INVOLVING DNA METHYLATION AND HISTONE MODIFICATIONS, ARE MAINTAINED UPON SOMATIC CELL REPLICATION, AND ARE FUNDAMENTAL MECHANISMS FOR CELLULAR MEMORY. DNA METHYLATION OF PROMOTER CPG ISLANDS OF TUMOR-SUPPRESSOR GENES CAN SILENCE THEIR DOWNSTREAM GENES, AND CAN BE CAUSALLY INVOLVED IN CANCER DEVELOPMENT AND PROGRESSION. SINCE THIS EFFECT IS THE SAME WITH THAT OF INACTIVATING MUTATIONS, THE NATURES OF DNA METHYLATION WERE ONCE CONSIDERED TO BE SIMILAR TO MUTATIONS. HOWEVER, RECENTLY, IT WAS REVEALED THAT A LARGE NUMBER OF EPIGENETIC ALTERATIONS ARE PRESENT IN A SINGLE CANCER CELL, THAT A LARGE NUMBER OF CELLS HAVE AN EPIGENETIC ALTERATION OF A SPECIFIC GENE IN NON-CANCEROUS, THUS POLYCLONAL, TISSUES, THAT GENE SPECIFICITY IN METHYLATION INDUCTION IS PRESENT ACCORDING TO TISSUE TYPES AND INDUCERS, AND THAT CHRONIC INFLAMMATION IS DEEPLY INVOLVED IN METHYLATION INDUCTION. THESE FACTS SUGGEST THAT EPIGENETIC ALTERATIONS OF KEY GENES INVOLVED IN ACQUIRED CHRONIC DISORDERS CAN BE PRESENT IN A SIGNIFICANT FRACTION OF CELLS IN A TISSUE, AND THUS CAN IMPAIR THE FUNCTION OF THE TISSUE. ASSOCIATIONS BETWEEN EPIGENETIC ALTERATIONS AND BEHAVIOR, MEMORY, MENTAL DISORDERS, NEUROLOGICAL DISORDERS, METABOLIC DISORDERS, ALLERGY, AUTOIMMUNE DISORDERS, AND OTHER DISORDERS HAVE BEEN REPORTED. FURTHER RESEARCH IN THE FIELD IS NECESSARY TO CLARIFY THE CAUSAL ROLES OF THESE EPIGENETIC ALTERATIONS IN DISEASE DEVELOPMENT, AND TO APPLY THE FINDINGS TO NEW STRATEGIES OF DISEASE PREVENTION, DIAGNOSIS, AND TREATMENT. 2010 12 2122 32 EPIGENETIC IMPACT OF INFECTION ON CARCINOGENESIS: MECHANISMS AND APPLICATIONS. VIRAL AND BACTERIAL INFECTIONS ARE INVOLVED IN THE DEVELOPMENT OF HUMAN CANCERS, SUCH AS LIVER, NASOPHARYNGEAL, CERVICAL, HEAD AND NECK, AND GASTRIC CANCERS. ABERRANT DNA METHYLATION IS FREQUENTLY PRESENT IN THESE CANCERS, AND SOME OF THE ABERRANTLY METHYLATED GENES ARE CAUSALLY INVOLVED IN CANCER DEVELOPMENT AND PROGRESSION. NOTABLY, ABERRANT DNA METHYLATION CAN BE PRESENT EVEN IN NON-CANCEROUS OR PRECANCEROUS TISSUES, AND ITS LEVELS CORRELATE WITH THE RISK OF CANCER DEVELOPMENT, PRODUCING A SO-CALLED 'EPIGENETIC FIELD FOR CANCERIZATION'. MECHANISTICALLY, MOST VIRAL OR BACTERIAL INFECTIONS INDUCE DNA METHYLATION INDIRECTLY VIA CHRONIC INFLAMMATION, BUT RECENT STUDIES HAVE INDICATED THAT SOME VIRUSES HAVE DIRECT EFFECTS ON THE EPIGENETIC MACHINERY OF HOST CELLS. FROM A TRANSLATIONAL VIEWPOINT, A RECENT MULTICENTER PROSPECTIVE COHORT STUDY DEMONSTRATED THAT ASSESSMENT OF THE EXTENT OF ALTERATIONS IN DNA METHYLATION IN NON-CANCEROUS TISSUES CAN BE USED TO PREDICT CANCER RISK. FURTHERMORE, SUPPRESSION OF ABERRANT DNA METHYLATION WAS SHOWN TO BE A USEFUL STRATEGY FOR CANCER PREVENTION IN AN ANIMAL MODEL. HERE, WE REVIEW THE INVOLVEMENT OF ABERRANT DNA METHYLATION IN VARIOUS TYPES OF INFECTION-ASSOCIATED CANCERS, ALONG WITH INDIVIDUAL INDUCTION MECHANISMS, AND WE DISCUSS THE APPLICATION OF THESE FINDINGS FOR CANCER PREVENTION, DIAGNOSIS, AND THERAPY. 2016 13 4228 27 METHYLATION OF INFLAMMATORY CELLS IN LUNG DISEASES. THIS CHAPTER OVERVIEWS ROLES OF DNA METHYLATION IN INFLAMMATORY CELL BIOLOGY WITH THE FOCUSES ON LYMPHOCYTES AND MACROPHAGES/MONOCYTES IN LUNG DISEASES, ALTHOUGH THE MOLECULAR MECHANISMS BY WHICH TARGET GENES ARE METHYLATED AND REGULATED IN LUNG DISEASES REMAIN UNCLEAR. MOST OF EPIGENETIC STUDIES ON DNA METHYLATION OF TARGET GENES IN LUNG DISEASES MAINLY DEMONSTRATED THE CORRELATION OF DNA METHYLATION OF TARGET GENES WITH THE LEVELS OF OTHER CORRESPONDING FACTORS, WITH THE SPECIFICITY OF CLINICAL PHENOMES, AND WITH THE SEVERITY OF LUNG DISEASES. THERE IS AN URGENT NEED TO IDENTIFY AND VALIDATE THE SPECIFICITY AND REGULATORY MECHANISMS OF INFLAMMATORY CELL EPIGENETICS IN DEPTH. THE EPIGENETIC HETEROGENEITY AMONG DIFFERENT SUBSETS OF T CELLS AND AMONG PROMOTERS OR NON-PROMOTERS OF TARGET GENES SHOULD BE FURTHERMORE CLARIFIED IN ACUTE OR CHRONIC LUNG DISEASES AND CANCERS. THE HYPER/HYPO-METHYLATION AND MODIFICATIONS OF CHROMOSOL AND EXTRACHROMOSOMAL DNA MAY RESULT IN ALTERNATIONS IN PROTEINS WITHIN INFLAMMATORY CELLS, WHICH CAN BE IDENTIFIED AS DISEASE-SPECIFIC BIOMARKERS AND THERAPEUTIC TARGETS. 2020 14 6371 42 THE ROLE OF MICRORNAS IN THE PATHOGENESIS AND TREATMENT OF HEMATOPOIETIC MALIGNANCIES. MICRORNAS (MIRNAS) COMPRISE A RECENTLY DISCOVERED CLASS OF NON-CODING RNAS WITH REGULATORY FUNCTIONS IN POST-TRANSCRIPTIONAL GENE EXPRESSION CONTROL. MANY MIRNAS ARE LOCATED IN GENOMIC REGIONS THAT ARE FREQUENTLY DELETED IN CANCER, OR ARE SUBJECT TO EPIGENETIC AND TRANSCRIPTIONAL DEREGULATION IN CANCER CELLS. THE MIRNA TRANSCRIPTOME OF CANCER CELLS IS VERY DIFFERENT FROM THAT OF THEIR NORMAL CELL COUNTERPARTS. MIRNAS CAN EXHIBIT ONCOGENIC OR TUMOR SUPPRESSIVE OR EVEN BOTH PROPERTIES DEPENDING ON THE SPECIFIC TARGETS AND CELLULAR CONTEXT. IT IS BECOMING INCREASINGLY CLEAR THAT MIRNAS NOT ONLY SERVE AS USEFUL TUMOR BIOMARKERS WITH IMPLICATIONS FOR DIAGNOSIS, PROGNOSIS AND THE PREDICTION OF TREATMENT RESPONSES, BUT MAY ALSO BE USED FOR TARGETED CANCER TREATMENT AND EVEN AS THERAPEUTICS. IN THIS REVIEW, WE PROVIDE AN OVERVIEW OF RECENT ADVANCES IN OUR UNDERSTANDING OF THE TUMOR SUPPRESSOR MIRNAS AND ONCOMIRS INVOLVED IN THE PATHOGENESIS OF LEUKEMIAS AND LYMPHOMAS, AND THEIR TARGET TRANSCRIPTS IN CANCER SIGNALING NETWORKS. IN PARTICULAR, WE FOCUS ON THE ROLE OF MIRNAS IN CHRONIC LYMPHOCYTIC AND ACUTE LYMPHOBLASTIC LEUKEMIA AND IN B-CELL LYMPHOMAS. IN THE SECOND PART, WE REVIEW THE VARIOUS ALTERNATIVE STRATEGIES OF TARGETING MIRNAS IN CANCER THERAPY. METHODS OF ONCOMIR ANTAGONIZATION BY ANTAGOMIRS OR LOCKED NUCLEID ACIDS ARE CONTRASTED WITH STRATEGIES THAT HARNESS THE TUMOR SUPPRESSIVE PROPERTIES OF CERTAIN MIRNAS FOR CANCER TREATMENT. PRECLINICAL PROGRESS, ALSO WITH REGARD TO DELIVERY STRATEGIES, POSSIBLE SIDE EFFECTS AND OTHER PHARMACOLOGICAL ASPECTS, IS PRESENTED ALONG WITH RESULTS FROM THE FIRST HUMAN TRIALS ASSESSING THE SAFETY AND EFFICACY OF MIRNA-TARGETING THERAPEUTICS. 2013 15 2022 36 EPIGENETIC CHANGES ASSOCIATED WITH DISEASE PROGRESSION IN A MOUSE MODEL OF CHILDHOOD ALLERGIC ASTHMA. DEVELOPMENT OF ASTHMA IN CHILDHOOD IS LINKED TO VIRAL INFECTIONS OF THE LOWER RESPIRATORY TRACT IN EARLY LIFE, WITH SUBSEQUENT CHRONIC EXPOSURE TO ALLERGENS. PROGRESSION TO PERSISTENT ASTHMA IS ASSOCIATED WITH A TH2-BIASED IMMUNOLOGICAL RESPONSE AND STRUCTURAL REMODELLING OF THE AIRWAYS. THE UNDERLYING MECHANISMS ARE UNCLEAR, BUT COULD INVOLVE EPIGENETIC CHANGES. TO INVESTIGATE THIS, WE EMPLOYED A RECENTLY DEVELOPED MOUSE MODEL IN WHICH SELF-LIMITED NEONATAL INFECTION WITH A PNEUMOVIRUS, FOLLOWED BY SENSITISATION TO OVALBUMIN VIA THE RESPIRATORY TRACT AND LOW-LEVEL CHRONIC CHALLENGE WITH AEROSOLISED ANTIGEN, LEADS TO DEVELOPMENT OF AN ASTHMATIC PHENOTYPE. WE ASSESSED EXPRESSION OF MICRORNA BY CELLS IN THE PROXIMAL AIRWAYS, COMPARING CHANGES OVER THE PERIOD OF DISEASE PROGRESSION, AND USED TARGET PREDICTION DATABASES TO IDENTIFY GENES LIKELY TO BE UP- OR DOWNREGULATED AS A CONSEQUENCE OF ALTERED REGULATION OF MICRORNA. IN PARALLEL, WE ASSESSED DNA METHYLATION IN PULMONARY CD4(+) T CELLS. WE FOUND THAT A LIMITED NUMBER OF MICRORNAS EXHIBITED MARKED UP- OR DOWNREGULATION FOLLOWING EARLY-LIFE INFECTION AND SENSITISATION, FOR MANY OF WHICH THE LEVELS OF EXPRESSION WERE FURTHER CHANGED FOLLOWING CHRONIC CHALLENGE WITH THE SENSITIZING ANTIGEN. TARGETS OF THESE MICRORNAS INCLUDED GENES INVOLVED IN IMMUNE OR INFLAMMATORY RESPONSES (E.G. GATA3, KITL) AND IN TISSUE REMODELLING (E.G. IGF1, TGFBR1), AS WELL AS GENES FOR VARIOUS TRANSCRIPTION FACTORS AND SIGNALLING PROTEINS. IN PULMONARY CD4(+) T CELLS, THERE WAS SIGNIFICANT DEMETHYLATION AT PROMOTER SITES FOR INTERLEUKIN-4 AND INTERFERON-GAMMA, THE LATTER INCREASING FOLLOWING CHRONIC CHALLENGE. WE CONCLUDE THAT, IN THIS MODEL, PROGRESSION TO AN ASTHMATIC PHENOTYPE IS LINKED TO EPIGENETIC REGULATION OF GENES ASSOCIATED WITH INFLAMMATION AND STRUCTURAL REMODELLING, AND WITH T-CELL COMMITMENT TO A TH2 IMMUNOLOGICAL RESPONSE. EPIGENETIC CHANGES ASSOCIATED WITH THIS PATTERN OF GENE ACTIVATION MIGHT PLAY A ROLE IN THE DEVELOPMENT OF CHILDHOOD ASTHMA. 2013 16 2926 28 GENERATION OF AN EPIGENETIC SIGNATURE BY CHRONIC HYPOXIA IN PROSTATE CELLS. INCREASING LEVELS OF TISSUE HYPOXIA HAVE BEEN REPORTED AS A NATURAL FEATURE OF THE AGING PROSTATE GLAND AND MAY BE A RISK FACTOR FOR THE DEVELOPMENT OF PROSTATE CANCER. IN THIS STUDY, WE HAVE USED PWR-1E BENIGN PROSTATE EPITHELIAL CELLS AND AN EQUIVALENTLY AGED HYPOXIA-ADAPTED PWR-1E SUB-LINE TO IDENTIFY PHENOTYPIC AND EPIGENETIC CONSEQUENCES OF CHRONIC HYPOXIA IN PROSTATE CELLS. WE HAVE IDENTIFIED A SIGNIFICANTLY ALTERED CELLULAR PHENOTYPE IN RESPONSE TO CHRONIC HYPOXIA AS CHARACTERIZED BY INCREASED RECEPTOR-MEDIATED APOPTOTIC RESISTANCE, THE INDUCTION OF CELLULAR SENESCENCE, INCREASED INVASION AND THE INCREASED SECRETION OF IL-1 BETA, IL6, IL8 AND TNFALPHA CYTOKINES. IN ASSOCIATION WITH THESE PHENOTYPIC CHANGES AND THE ABSENCE OF HIF-1 ALPHA PROTEIN EXPRESSION, WE HAVE DEMONSTRATED SIGNIFICANT INCREASES IN GLOBAL LEVELS OF DNA METHYLATION AND H3K9 HISTONE ACETYLATION IN THESE CELLS, CONCOMITANT WITH THE INCREASED EXPRESSION OF DNA METHYLTRANSFERASE DMNT3B AND GENE-SPECIFIC CHANGES IN DNA METHYLATION AT KEY IMPRINTING LOCI. IN CONCLUSION, WE HAVE DEMONSTRATED A GENOME-WIDE ADJUSTMENT OF DNA METHYLATION AND HISTONE ACETYLATION UNDER CHRONIC HYPOXIC CONDITIONS IN THE PROSTATE. THESE EPIGENETIC SIGNATURES MAY REPRESENT AN ADDITIONAL MECHANISM TO PROMOTE AND MAINTAIN A HYPOXIC-ADAPTED CELLULAR PHENOTYPE WITH A POTENTIAL ROLE IN TUMOUR DEVELOPMENT. 2009 17 208 30 ACTIVATION-INDUCED CYTIDINE DEAMINASE (AID) LINKING IMMUNITY, CHRONIC INFLAMMATION, AND CANCER. ACTIVATION-INDUCED CYTIDINE DEAMINASE (AID) IS CRITICALLY INVOLVED IN CLASS SWITCH RECOMBINATION AND SOMATIC HYPERMUTATION OF IG LOCI RESULTING IN DIVERSIFICATION OF ANTIBODIES REPERTOIRE AND PRODUCTION OF HIGH-AFFINITY ANTIBODIES AND AS SUCH REPRESENTS A PHYSIOLOGICAL TOOL TO INTRODUCE DNA ALTERATIONS. THESE PROCESSES TAKE PLACE WITHIN GERMINAL CENTERS OF SECONDARY LYMPHOID ORGANS. UNDER PHYSIOLOGICAL CONDITIONS, AID IS EXPRESSED PREDOMINANTLY IN ACTIVATED B LYMPHOCYTES. BECAUSE OF THE MUTAGENIC AND RECOMBINOGENIC POTENTIAL OF AID, ITS EXPRESSION AND ACTIVITY IS TIGHTLY REGULATED ON DIFFERENT LEVELS TO MINIMIZE THE RISK OF UNWANTED DNA DAMAGE. HOWEVER, CHRONIC INFLAMMATION AND, PROBABLY, COMBINATION OF OTHER NOT-YET-IDENTIFIED FACTORS ARE ABLE TO CREATE A MICROENVIRONMENT SUFFICIENT FOR TRIGGERING AN ABERRANT AID EXPRESSION IN B CELLS AND, IMPORTANTLY, IN NON-B-CELL BACKGROUND. UNDER THESE CIRCUMSTANCES, AID MAY TARGET ALSO NON-IG GENES, INCLUDING CANCER-RELATED GENES AS ONCOGENES, TUMOR SUPPRESSOR GENES, AND GENOMIC STABILITY GENES, AND MODULATE BOTH GENETIC AND EPIGENETIC INFORMATION. DESPITE ONGOING PROGRESS, THE COMPLETE UNDERSTANDING OF FUNDAMENTAL ASPECTS IS STILL LACKING AS (1) WHAT ARE THE CRUCIAL FACTORS TRIGGERING AN ABERRANT AID EXPRESSION/ACTIVITY INCLUDING THE IMPACT OF TH2-DRIVEN INFLAMMATION AND (2) TO WHAT EXTENT MAY ABERRANT AID IN HUMAN NON-B CELLS LEAD TO ABNORMAL CELL STATE ASSOCIATED WITH AN INCREASED RATE OF GENOMIC ALTERATIONS AS POINT MUTATIONS, SMALL INSERTIONS OR DELETIONS, AND/OR RECURRENT CHROMOSOMAL TRANSLOCATIONS DURING SOLID TUMOR DEVELOPMENT AND PROGRESSION. 2012 18 5288 24 PROSPECTS FOR EPIGENETIC COMPOUNDS IN THE TREATMENT OF AUTOIMMUNE DISEASE. THERE IS GROWING EVIDENCE FOR A ROLE FOR EPIGENETIC MECHANISMS IN THE DEVELOPMENT OF AUTOIMMUNE DISEASES. IN MOST CASES OFAUTOIMMUNE DISEASE THE PRECISE EPIGENETIC MECHANISM INVOLVED REMAINS TO BE RESOLVED, HOWEVER DNA HYPOMETHYLATION ACCOMPANIED BY HYPOACETYLATION OFHISTONE H3/H4 IS COMMONLY OBSERVED. DUE TO THE REVERSIBLE NATURE OF EPIGENETIC MARKS THEIR MAINTENANCE ENZYMES SUCH AS DNA METHYLTRANSFERASES (DNMTS), HISTONE DEACETYLASES (HDACS) AND HISTONE LYSINE METHYLTRANSFERASES (HKMT) ARE ATTRACTIVE DRUG TARGETS. SMALL MOLECULE INHIBITORS OF HISTONE MODIFICATION AND DNA METHYLATION MAINTENANCE ARE INCREASINGLY BECOMING AVAILABLE AND WILL BE USEFUL CHEMICAL BIOLOGICAL TOOLS TO DISSECT EPIGENETIC MECHANISMS IN THESE DISEASES. HOWEVER, ALTHOUGH EPIGENETIC THERAPIES USED IN CANCER TREATMENT ARE A PROMISING STARTING POINT FOR THE EXPLORATION OF AUTOIMMUNE DISEASE TREATMENT, THERE IS A REQUIREMENT FOR MORE SPECIFIC AND LESS TOXIC AGENTS FOR THESE CHRONIC DISEASES OR FOR USE AS CHEMOPREVENTATIVE AGENTS. 2011 19 834 30 CHEMICAL BIOLOGY OF LYSINE DEMETHYLASES. ABNORMAL LEVELS OF DNA METHYLATION AND/OR HISTONE MODIFICATIONS ARE OBSERVED IN PATIENTS WITH A WIDE VARIETY OF CHRONIC DISEASES. METHYLATION OF LYSINES WITHIN HISTONE TAILS IS A KEY MODIFICATION THAT CONTRIBUTES TO INCREASED GENE EXPRESSION OR REPRESSION DEPENDING ON THE SPECIFIC RESIDUE AND DEGREE OF METHYLATION, WHICH IS IN TURN CONTROLLED BY THE INTERPLAY OF LYSINE METHYL TRANSFERASES AND DEMETHYLASES. DRUGS THAT TARGET THESE AND OTHER ENZYMES CONTROLLING CHROMATIN MODIFICATIONS CAN MODULATE THE EXPRESSION OF CLUSTERS OF GENES, POTENTIALLY OFFERING HIGHER THERAPEUTIC EFFICACY THAN CLASSICAL AGENTS ACTING ON DOWNSTREAM BIOCHEMICAL PATHWAYS THAT ARE SUSCEPTIBLE TO DEGENERACY. LYSINE DEMETHYLASES, FIRST DISCOVERED IN 2004, ARE THE SUBJECT OF INCREASING INTEREST AS THERAPEUTIC TARGETS. THIS REVIEW PROVIDES AN OVERVIEW OF RECENT FINDINGS IMPLICATING LYSINE DEMETHYLASES IN A RANGE OF THERAPEUTIC AREAS INCLUDING ONCOLOGY, IMMUNOINFLAMMATION, METABOLIC DISORDERS, NEUROSCIENCE, VIROLOGY AND REGENERATIVE MEDICINE, TOGETHER WITH A SUMMARY OF RECENT ADVANCES IN STRUCTURAL BIOLOGY AND SMALL MOLECULE INHIBITOR DISCOVERY, SUPPORTING THE TRACTABILITY OF THE PROTEIN FAMILY FOR THE DEVELOPMENT OF SELECTIVE DRUGLIKE INHIBITORS. 2011 20 1518 30 DNA METHYLATION AS AN EPIGENETIC MECHANISM IN THE DEVELOPMENT OF MULTIPLE SCLEROSIS. THE EPIGENETIC MECHANISMS OF GENE EXPRESSION REGULATION ARE A GROUP OF THE KEY CELLULAR AND MOLECULAR PATHWAYS THAT LEAD TO INHERITED ALTERATIONS IN GENES' ACTIVITY WITHOUT CHANGING THEIR CODING SEQUENCE. DNA METHYLATION AT THE C5 POSITION OF CYTOSINE IN CPG DINUCLEOTIDES IS AMONGST THE CENTRAL EPIGENETIC MECHANISMS. CURRENTLY, THE NUMBER OF STUDIES THAT ARE DEVOTED TO THE IDENTIFICATION OF METHYLATION PATTERNS SPECIFIC TO MULTIPLE SCLEROSIS (MS), A SEVERE CHRONIC AUTOIMMUNE DISEASE OF THE CENTRAL NERVOUS SYSTEM, IS ON A RAPID RISE. HOWEVER, THE ISSUE OF THE CONTRIBUTION OF DNA METHYLATION TO THE DEVELOPMENT OF THE DIFFERENT CLINICAL PHENOTYPES OF THIS HIGHLY HETEROGENEOUS DISEASE HAS ONLY BEGUN TO ATTRACT THE ATTENTION OF RESEARCHERS. THIS REVIEW SUMMARIZES THE DATA ON THE MOLECULAR MECHANISMS UNDERLYING DNA METHYLATION AND THE MS RISK FACTORS THAT CAN AFFECT THE DNA METHYLATION PROFILE AND, THEREBY, MODULATE THE EXPRESSION OF THE GENES INVOLVED IN THE DISEASE'S PATHOGENESIS. THE FOCUS OF OUR ATTENTION IS CENTERED ON THE ANALYSIS OF THE PUBLISHED DATA ON THE DIFFERENTIAL METHYLATION OF DNA FROM VARIOUS BIOLOGICAL SAMPLES OF MS PATIENTS OBTAINED USING BOTH THE CANDIDATE GENE APPROACH AND HIGH-THROUGHPUT METHODS. 2021