1 950 121 CHRONIC MILD STRESS EXACERBATES SEVERITY OF EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS IN ASSOCIATION WITH ALTERED NON-CODING RNA AND METABOLIC BIOMARKERS. THE CAUSAL FACTORS DETERMINING THE ONSET AND SEVERITY OF MULTIPLE SCLEROSIS (MS) ARE NOT WELL UNDERSTOOD. HERE, WE INVESTIGATED THE INFLUENCE OF CHRONIC STRESS ON CLINICAL SYMPTOMS, METABOLIC AND EPIGENETIC MANIFESTATIONS OF EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS (EAE), A COMMON ANIMAL MODEL OF MS. LEWIS RATS WERE IMMUNIZED FOR MONOPHASIC EAE WITH MBP(69-88) AND WERE EXPOSED TO CHRONIC STRESS FOR 37DAYS STARTING 7DAYS PRIOR TO IMMUNIZATION. THE EXPOSURE TO STRESS ACCELERATED AND EXACERBATED THE CLINICAL SYMPTOMS OF EAE. BOTH STRESS AND EAE ALSO DISRUPTED METABOLIC STATUS AS INDICATED BY TRACE ELEMENTAL ANALYSIS IN BODY HAIR. STRESS PARTICULARLY EXACERBATED CHLORINE DEPOSITION IN EAE ANIMALS. MOREOVER, DEEP SEQUENCING REVEALED A CONSIDERABLE IMPACT OF STRESS ON MICRORNA EXPRESSION IN EAE. EAE BY ITSELF UPREGULATED MICRORNA EXPRESSION IN LUMBAR SPINAL CORD, INCLUDING MIR-21, MIR-142-3P, MIR-142-5P, MIR-146A, AND MIR-155. STRESS IN EAE FURTHER UP-REGULATED MIR-16, MIR-146A AND MIR-155 LEVELS. THE LATTER TWO MICRORNAS ARE RECOGNIZED BIOMARKERS OF HUMAN MS. THUS, STRESS MAY SYNERGISTICALLY EXACERBATE SEVERITY OF EAE BY ALTERING EPIGENETIC REGULATORY PATHWAYS. THE FINDINGS SUGGEST THAT STRESS MAY REPRESENT A SIGNIFICANT RISK FACTOR FOR SYMPTOMATIC DETERIORATION IN MS. STRESS-RELATED METABOLIC AND MICRORNA SIGNATURES SUPPORT THEIR VALUE AS BIOMARKERS FOR PREDICTING THE RISK AND SEVERITY OF MS. 2017 2 4590 29 NANOPORE SEQUENCING IDENTIFIES DIFFERENTIALLY METHYLATED GENES IN THE CENTRAL NERVOUS SYSTEM IN EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS. MULTIPLE SCLEROSIS (MS) IS A CHRONIC AUTOIMMUNE-MEDIATED DEMYELINATING DISEASE OF THE CENTRAL NERVOUS SYSTEM (CNS) THAT MIGHT BE TRIGGERED BY ABERRANT EPIGENETIC CHANGES IN THE GENOME. DNA METHYLATION IS THE MOST STUDIED EPIGENETIC MECHANISM THAT PARTICIPATES IN MS PATHOGENESIS. HOWEVER, THE OVERALL METHYLATION LEVEL IN THE CNS OF MS PATIENTS REMAINS ELUSIVE. WE USED DIRECT LONG-READ NANOPORE DNA SEQUENCING AND CHARACTERIZED THE DIFFERENTIALLY METHYLATED GENES IN THE BRAIN FROM MICE WITH EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS (EAE), AN ANIMAL MODEL OF MS. WE IDENTIFIED 163 HYPOMETHYLATED PROMOTERS AND 327 HYPERMETHYLATED PROMOTERS. THESE GENOMIC ALTERATIONS WERE LINKED TO VARIOUS BIOLOGICAL PROCESSES INCLUDING METABOLISM, IMMUNE RESPONSES, NEURAL ACTIVITIES, AND MITOCHONDRIAL DYNAMICS, ALL OF WHICH ARE VITAL FOR EAE DEVELOPMENT. OUR RESULTS INDICATE A GREAT POTENTIAL OF NANOPORE SEQUENCING IN IDENTIFYING GENOMIC DNA METHYLATION IN EAE AND PROVIDE IMPORTANT GUIDANCE FOR FUTURE STUDIES INVESTIGATING THE MS/EAE PATHOLOGY. 2023 3 4921 34 PARENT-OF-ORIGIN EFFECTS IMPLICATE EPIGENETIC REGULATION OF EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS AND IDENTIFY IMPRINTED DLK1 AS A NOVEL RISK GENE. PARENT-OF-ORIGIN EFFECTS COMPRISE A RANGE OF GENETIC AND EPIGENETIC MECHANISMS OF INHERITANCE. RECENTLY, DETECTION OF SUCH EFFECTS IMPLICATED EPIGENETIC MECHANISMS IN THE ETIOLOGY OF MULTIPLE SCLEROSIS (MS), A CHRONIC INFLAMMATORY DISEASE OF THE CENTRAL NERVOUS SYSTEM. WE HERE SOUGHT TO DISSECT THE MAGNITUDE AND THE TYPE OF PARENT-OF-ORIGIN EFFECTS IN THE PATHOGENESIS OF EXPERIMENTAL NEUROINFLAMMATION UNDER CONTROLLED ENVIRONMENTAL CONDITIONS. WE INVESTIGATED INHERITANCE OF AN MS-LIKE DISEASE IN RAT, EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS (EAE), USING A BACKCROSS STRATEGY DESIGNED TO IDENTIFY THE PARENTAL ORIGIN OF DISEASE-PREDISPOSING ALLELES. A STRIKING 37-54% OF ALL DETECTED DISEASE-PREDISPOSING LOCI DEPENDED ON PARENTAL TRANSMISSION. ADDITIONALLY, THE Y CHROMOSOME FROM THE SUSCEPTIBLE STRAIN CONTRIBUTED TO DISEASE SUSCEPTIBILITY. ACCOUNTING FOR PARENT-OF-ORIGIN ENABLED MORE POWERFUL AND PRECISE IDENTIFICATION OF NOVEL RISK FACTORS AND INCREASED THE DISEASE VARIANCE EXPLAINED BY THE IDENTIFIED FACTORS BY 2-4-FOLD. THE MAJORITY OF LOCI DISPLAYED AN IMPRINTING-LIKE PATTERN WHEREBY A GENE EXPRESSED ONLY FROM THE MATERNAL OR PATERNAL COPY EXERTS AN EFFECT. IN PARTICULAR, A LOCUS ON CHROMOSOME 6 COMPRISES A WELL-KNOWN CLUSTER OF IMPRINTED GENES INCLUDING THE PATERNALLY EXPRESSED DLK1, AN ATYPICAL NOTCH LIGAND. DISEASE-PREDISPOSING ALLELES AT THE LOCUS CONFERRED LOWER DLK1 EXPRESSION IN RATS AND, TOGETHER WITH DATA FROM TRANSGENIC OVEREXPRESSING DLK1 MICE, DEMONSTRATE THAT REDUCED DLK1 DRIVES MORE SEVERE DISEASE AND MODULATES ADAPTIVE IMMUNE REACTIONS IN EAE. OUR FINDINGS SUGGEST A SIGNIFICANT EPIGENETIC CONTRIBUTION TO THE ETIOLOGY OF EAE. INCORPORATING THESE EFFECTS ENABLES MORE POWERFUL AND PRECISE IDENTIFICATION OF NOVEL RISK FACTORS WITH DIAGNOSTIC AND PROGNOSTIC IMPLICATIONS FOR COMPLEX DISEASE. 2014 4 1994 27 EPIGENETIC AND GENE EXPRESSION ALTERATIONS OF FOXP3 IN THE T CELLS OF EAE MOUSE MODEL OF MULTIPLE SCLEROSIS. MULTIPLE SCLEROSIS (MS) IS A CHRONIC AUTOIMMUNE DISEASE WITH DEMYELINATION AND NEURODEGENERATION OF THE CENTRAL NERVOUS SYSTEM. IT HAS BEEN SHOWN THAT THE REGULATORY T (TREG) CELLS ARE RESPONSIBLE FOR MAINTAINING TOLERANCE TO SELF-ANTIGENS AND CAN SUPPRESS THE AUTOIMMUNE PROCESS IN SEVERAL ANIMAL MODELS SUCH AS EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS (EAE), A MOUSE MODEL OF MS. RECENT BASIC STUDIES HAVE DEMONSTRATED THAT FORKHEAD BOX P (FOXP3) AND BTB DOMAIN AND CNC HOMOLOG 2 (BACH2) ARE THE MASTER TRANSCRIPTION FACTORS OF THESE CELLS PLAYING A PIVOTAL ROLE IN THE POLARIZATION OF NAIVE T CELLS INTO TREG CELLS. IN THE CURRENT STUDY, THE EXPRESSION OF FOXP3 AND BACH2 GENES AND FOXP3 PROMOTER METHYLATION WERE EVALUATED IN T CELLS OF THE EAE-INDUCED MICE. THE RESULTS OF THIS STUDY SHOWED A PROMINENT AND SIGNIFICANT HYPERMETHYLATION OF THE FOXP3 GENE PROMOTER IN THE EAE-INDUCED MICE COMPARED TO THE SHAM AND CONTROL GROUPS. THE EXPRESSION OF FOXP3 AND BACH2 GENES WAS SIGNIFICANTLY DECREASED IN THE EAE GROUP IN COMPARISON WITH THE SHAM AND CONTROL GROUPS. THIS STUDY SUGGESTS THAT THE EPIGENETIC MODIFICATION OF FOXP3 GENE IS INVOLVED IN THE PATHOGENESIS OF EAE AND THIS COULD BE IMPORTANT IN THERAPY IN AN APPROPRIATE AND LOGICAL STATEMENT. 2017 5 6136 26 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 6 2139 30 EPIGENETIC INSIGHTS INTO MULTIPLE SCLEROSIS DISEASE PROGRESSION. MULTIPLE SCLEROSIS (MS), A CHRONIC INFLAMMATORY DEMYELINATING AND NEURODEGENERATIVE DISEASE OF THE CENTRAL NERVOUS SYSTEM, IS TODAY A LEADING CAUSE OF UNPREDICTABLE LIFELONG DISABILITY IN YOUNG ADULTS. THE TREATMENT OF PATIENTS IN PROGRESSIVE STAGES REMAINS HIGHLY CHALLENGING, ALLUDING TO OUR LIMITED UNDERSTANDING OF THE UNDERLYING PATHOLOGICAL PROCESSES. IN THIS REVIEW, WE PROVIDE INSIGHTS INTO THE MECHANISMS UNDERPINNING MS PROGRESSION FROM A PERSPECTIVE OF EPIGENETICS, THAT REFERS TO STABLE AND MITOTICALLY HERITABLE, YET REVERSIBLE, CHANGES IN THE GENOME ACTIVITY AND GENE EXPRESSION. WE FIRST RECAPITULATE FINDINGS FROM EPIGENETIC STUDIES EXAMINING THE BRAIN TISSUE OF PROGRESSIVE MS PATIENTS, WHICH SUPPORT A CONTRIBUTION OF DNA AND HISTONE MODIFICATIONS IN IMPAIRED OLIGODENDROCYTE DIFFERENTIATION, DEFECTIVE MYELINATION/REMYELINATION AND SUSTAINED NEURO-AXONAL VULNERABILITY. WE NEXT EXPLORE POSSIBILITIES FOR IDENTIFYING FACTORS AFFECTING PROGRESSION USING EASILY ACCESSIBLE TISSUES SUCH AS BLOOD BY COMPARING EPIGENETIC SIGNATURES IN PERIPHERAL IMMUNE CELLS AND BRAIN TISSUE. DESPITE MINOR OVERLAP AT INDIVIDUAL METHYLATION SITES, NEARLY 30% OF ALTERED GENES REPORTED IN PERIPHERAL IMMUNE CELLS OF PROGRESSIVE MS PATIENTS WERE FOUND IN BRAIN TISSUE, JOINTLY CONVERGING ON ALTERATIONS OF NEURONAL FUNCTIONS. WE FURTHER SPECULATE ABOUT THE MECHANISMS UNDERLYING SHARED EPIGENETIC PATTERNS BETWEEN BLOOD AND BRAIN, WHICH LIKELY IMPLY THE INFLUENCE OF INTERNAL (GENETIC CONTROL) AND/OR EXTERNAL (E.G. SMOKING AND AGEING) FACTORS IMPRINTING A COMMON SIGNATURE IN BOTH COMPARTMENTS. OVERALL, WE PROPOSE THAT EPIGENETICS MIGHT SHED LIGHT ON CLINICALLY RELEVANT MECHANISMS INVOLVED IN DISEASE PROGRESSION AND OPEN NEW AVENUES FOR THE TREATMENT OF PROGRESSIVE MS PATIENTS IN THE FUTURE. 2020 7 4439 29 MOLECULAR GENETIC AND EPIGENETIC BASIS OF MULTIPLE SCLEROSIS. MULTIPLE SCLEROSIS (MS) IS A CHRONIC IMMUNE-MEDIATED DISEASE OF SPINAL CORD AND BRAIN. THE INITIAL EVENT IN MS OCCURS WHEN ACTIVATED CD4(+) T CELLS IN PERIPHERY EXACERBATES IMMUNE RESPONSES BY STIMULATING IMMUNE CELLS SUCH AS B CELLS, CD8(+) CELLS, MAST CELLS, GRANULOCYTES AND MONOCYTES. THESE PROINFLAMMATORY CELLS PASS BLOOD BRAIN BARRIER BY SECRETING PROINFLAMMATORY CYTOKINES INCLUDING TNF-ALPHA AND INF-(GAMMA) WHICH ACTIVATE ADHESION FACTORS. APCS (ANTIGEN-PRESENTING CELLS) REACTIVATE CD4(+) T CELLS AFTER INFILTRATING THE CNS AND CD4(+) T CELLS PRODUCE CYTOKINES AND CHEMOKINES. THESE PROINFLAMMATORY CYTOKINES AGGRAVATE INFLAMMATION BY INDUCING MYELIN PHAGOCYTOSIS THROUGH MICROGLIA AND ASTROCYTES ACTIVATION. MS IS BELIEVED TO HAVE A MULTIFACTORIAL ORIGIN THAT INCLUDES A COMBINATION OF MULTIPLE GENETIC, ENVIRONMENTAL AND STOCHASTIC FACTORS. ALTHOUGH THE EXACT COMPONENT OF MS RISKS THAT CAN BE EXPLAINED BY THESE FACTORS IS DIFFICULT TO DETERMINE, ESTIMATES BASED ON GENETIC AND EPIDEMIOLOGICAL STUDIES SUGGEST THAT UP TO 60-70 % OF THE TOTAL RISK OF MS MAY BE CONTRIBUTE TO GENETIC FACTORS. IN CONTINUE, FIRSTLY WE PROVIDE AN OVERVIEW OF THE CURRENT UNDERSTANDING OF EPIGENETIC MECHANISMS, AND SO PRESENT EVIDENCE OF HOW THE EPIGENETIC MODIFICATIONS CONTRIBUTE TO INCREASED SUSCEPTIBILITY OF MS. WE ALSO EXPLAIN HOW SPECIFIED EPIGENETIC MODIFICATIONS MAY INFLUENCE THE PATHOPHYSIOLOGY AND KEY ASPECTS OF DISEASE IN MS (DEMYELINATION, REMYELINATION, INFLAMMATION, AND NEURODEGENERATION). FINALLY, WE TEND TO DISCUSS HOW ENVIRONMENTAL FACTORS AND EPIGENETIC MECHANISMS MAY INTERACT TO HAVE AN EFFECT ON MS RISK AND CLINICAL OUTCOME AND RECOMMEND NEW THERAPEUTIC INTERVENTIONS THAT MIGHT MODULATE PATIENTS' EPIGENETIC PROFILES. 2017 8 2909 33 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 9 5591 29 ROLE OF THE EPIGENETIC FACTOR SIRT7 IN NEUROINFLAMMATION AND NEUROGENESIS. EPIGENETIC REGULATORS ARE INCREASINGLY RECOGNIZED AS RELEVANT MODULATORS IN THE IMMUNE AND NERVOUS SYSTEM. THE CLASS OF SIRTUINS CONSISTS OF NAD(+)-DEPENDENT HISTONE DEACETYLASES THAT REGULATE TRANSCRIPTION. SIRTUIN FAMILY MEMBER SIRT1 HAS ALREADY BEEN SHOWN TO INFLUENCE THE DISEASE COURSE IN AN ANIMAL MODEL OF AUTOIMMUNE NEUROINFLAMMATION (EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS (EAE). A ROLE OF SIRT7, A RELATED EPIGENETIC REGULATOR, ON IMMUNE SYSTEM REGULATION HAS BEEN PROPOSED BEFORE, AS THESE MICE ARE MORE SUSCEPTIBLE TO DEVELOP INFLAMMATORY CARDIOMYOPATHY. SIRT7(-/-) ANIMALS SHOWED NO DIFFERENCES IN CLINICAL SCORE COMPARED TO WILD-TYPE LITTERMATES AFTER EAE INDUCTION WITH MYELIN OLIGODENDROCYTE GLYCOPROTEIN (MOG) PEPTIDE (35-55), ALTHOUGH WE FOUND SUBTLE IMMUNE ALTERATIONS AT DIFFERENT PHASES OF EAE AND DECREASED SURVIVAL OF NEWLY GENERATED NEURONS IN THE HIPPOCAMPUS. OUR DATA INDICATE THAT SIRT7 HAS A SLIGHT PROTECTIVE IMPACT ON BOTH THE ADAPTIVE IMMUNE SYSTEM AND NEUROGENESIS. HOWEVER, OVERALL THIS EPIGENETIC FACTOR IS NOT CAPABLE OF IMPACTING THE ACUTE OR CHRONIC PHASE OF NEUROINFLAMMATION. 2018 10 4368 30 MIRNA-DEPENDENT CD4(+) T CELL DIFFERENTIATION IN THE PATHOGENESIS OF MULTIPLE SCLEROSIS. MULTIPLE SCLEROSIS (MS) IS CHARACTERIZED BY MULTIFOCAL LESIONS, CHRONIC INFLAMMATORY CONDITION, AND DEGENERATIVE PROCESSES WITHIN THE CENTRAL NERVOUS SYSTEM (CNS) LEADING TO DEMYELINATION. THE MOST IMPORTANT CELLS INVOLVED IN ITS PATHOGENESIS ARE THOSE WHICH ARE CD4(+), PARTICULARLY PROINFLAMMATORY TH1/TH17 AND REGULATORY TREG. SIGNAL CASCADES ASSOCIATED WITH CD4(+) DIFFERENTIATION ARE REGULATED BY MICRORNAS (MIRNAS): SHORT, SINGLE-STRANDED RNAS, RESPONSIBLE FOR NEGATIVE REGULATION OF GENE EXPRESSION AT THE POSTTRANSCRIPTIONAL LEVEL. SEVERAL MIRNAS HAVE BEEN CONSISTENTLY REPORTED AS SHOWING DYSREGULATED EXPRESSION IN MS, AND THEIR EXPRESSION PATTERNS MAY BE ELEVATED OR DECREASED, DEPENDING ON THE FUNCTION OF SPECIFIC MIRNA IN THE IMMUNE SYSTEM. STUDIES IN MS PATIENTS INDICATE THAT, AMONG OTHERS, MIR-141, MIR-200A, MIR-155, MIR-223, AND MIR-326 ARE UPREGULATED, WHILE MIR-15B, MIR-20B, MIR-26A, AND MIR-30A ARE DOWNREGULATED. DYSREGULATION OF THESE MIRNAS MAY CONTRIBUTE TO THE IMBALANCE BETWEEN PRO- AND ANTI-INFLAMMATORY PROCESSES, SINCE THEIR TARGETS ARE ASSOCIATED WITH THE REGULATION OF TH1/TH17 AND TREG CELL DIFFERENTIATION. HIGHLY EXPRESSED MIRNAS CAN IN TURN SUPPRESS TRANSLATION OF KEY TH1/TH17 DIFFERENTIATION INHIBITORS. MIRNA DYSREGULATION MAY RESULT FROM THE IMPACT OF VARIOUS FACTORS AT EACH STAGE OF THEIR BIOGENESIS. IMMATURE MIRNA UNDERGOES MULTISTAGE TRANSCRIPTIONAL AND POSTTRANSCRIPTIONAL MODIFICATIONS; THEREFORE, ANY PROTEIN INVOLVED IN THE PROCESSING OF MIRNAS CAN POTENTIALLY LEAD TO DISTURBANCES IN THEIR EXPRESSION. EPIGENETIC MODIFICATIONS THAT HAVE A DIRECT IMPACT ON MIRNA GENE TRANSCRIPTION MAY ALSO PLAY AN IMPORTANT ROLE. 2021 11 1611 26 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 12 5710 25 SIRT1 DEFICIENCY IN MICROGLIA CONTRIBUTES TO COGNITIVE DECLINE IN AGING AND NEURODEGENERATION VIA EPIGENETIC REGULATION OF IL-1BETA. AGING IS THE PREDOMINANT RISK FACTOR FOR NEURODEGENERATIVE DISEASES. ONE KEY PHENOTYPE AS THE BRAIN AGES IS AN ABERRANT INNATE IMMUNE RESPONSE CHARACTERIZED BY PROINFLAMMATION. HOWEVER, THE MOLECULAR MECHANISMS UNDERLYING AGING-ASSOCIATED PROINFLAMMATION ARE POORLY DEFINED. WHETHER CHRONIC INFLAMMATION PLAYS A CAUSAL ROLE IN COGNITIVE DECLINE IN AGING AND NEURODEGENERATION HAS NOT BEEN ESTABLISHED. HERE WE REPORT A MECHANISTIC LINK BETWEEN CHRONIC INFLAMMATION AND AGING MICROGLIA AND A CAUSAL ROLE OF AGING MICROGLIA IN NEURODEGENERATIVE COGNITIVE DEFICITS. WE SHOWED THAT SIRT1 IS REDUCED WITH THE AGING OF MICROGLIA AND THAT MICROGLIAL SIRT1 DEFICIENCY HAS A CAUSATIVE ROLE IN AGING- OR TAU-MEDIATED MEMORY DEFICITS VIA IL-1BETA UPREGULATION IN MICE. INTERESTINGLY, THE SELECTIVE ACTIVATION OF IL-1BETA TRANSCRIPTION BY SIRT1 DEFICIENCY IS LIKELY MEDIATED THROUGH HYPOMETHYLATING THE SPECIFIC CPG SITES ON IL-1BETA PROXIMAL PROMOTER. IN HUMANS, HYPOMETHYLATION OF IL-1BETA IS STRONGLY ASSOCIATED WITH CHRONOLOGICAL AGE AND WITH ELEVATED IL-1BETA TRANSCRIPTION. OUR FINDINGS REVEAL A NOVEL EPIGENETIC MECHANISM IN AGING MICROGLIA THAT CONTRIBUTES TO COGNITIVE DEFICITS IN AGING AND NEURODEGENERATIVE DISEASES. 2015 13 1518 25 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 14 2119 30 EPIGENETIC HISTONE MODIFICATION REGULATES DEVELOPMENTAL LEAD EXPOSURE INDUCED HYPERACTIVITY IN RATS. LEAD (PB) EXPOSURE WAS COMMONLY CONSIDERED AS A HIGH ENVIRONMENTAL RISK FACTOR FOR THE DEVELOPMENT OF ATTENTION-DEFICIT/HYPERACTIVITY DISORDER (ADHD). HOWEVER, THE MOLECULAR BASIS OF THIS PATHOLOGICAL PROCESS STILL REMAINS ELUSIVE. IN LIGHT OF THE ROLE OF EPIGENETICS IN MODULATING THE NEUROLOGICAL DISEASE AND THE CAUSATIVE ENVIRONMENT, THE ALTERATIONS OF HISTONE MODIFICATIONS IN THE HIPPOCAMPUS OF RATS EXPOSED BY VARIOUS DOSES OF LEAD, ALONG WITH CONCOMITANT BEHAVIORAL DEFICITS, WERE INVESTIGATED IN THIS STUDY. ACCORDING TO THE FREE AND FORCED OPEN FIELD TEST, THERE SHOWED THAT IN A DOSAGE-DEPENDENT MANNER, LEAD EXPOSURE COULD RESULT IN THE INCREASED LOCOMOTOR ACTIVITY OF RATS, THAT IS, HYPERACTIVITY: A SUBTYPE OF ADHD. WESTERN BLOTTING ASSAYS REVEALED THAT THE LEVELS OF HISTONE ACETYLATION INCREASED SIGNIFICANTLY IN THE HIPPOCAMPUS BY CHRONIC LEAD EXPOSURE, WHILE NO DRAMATIC CHANGES WERE DETECTED IN TERMS OF EXPRESSION YIELDS OF ADHD-RELATED DOPAMINERGIC PROTEINS, INDICATING THAT HISTONE ACETYLATION PLAYS ESSENTIAL ROLES IN THIS TOXICANT-INVOLVED PATHOGENESIS. IN ADDITION, THE INCREASED LEVEL OF HISTONE ACETYLATION MIGHT BE ATTRIBUTED TO THE ENZYMATIC ACTIVITY OF P300, A TYPICAL HISTONE ACETYLTRANSFERASE, AS THE TRANSCRIPTIONAL LEVEL OF P300 WAS SIGNIFICANTLY INCREASED UPON HIGHER-DOSE PB EXPOSURE. IN SUMMARY, THIS STUDY FIRST DISCOVERED THE EPIGENETIC MECHANISM BRIDGING THE ENVIRONMENTAL INFLUENCE (PB) AND THE DISEASE ITSELF (ADHD) IN THE HISTONE MODIFICATION LEVEL, PAVING THE WAY FOR THE COMPREHENSIVE UNDERSTANDING OF ADHD'S ETIOLOGY AND IN FURTHER STEPS, ESTABLISHING THE THERAPY STRATEGY OF THIS WIDESPREAD NEUROLOGICAL DISORDER. 2014 15 3549 30 IMMUNOSENESCENCE AND MULTIPLE SCLEROSIS. CHANGES IN THE IMMUNE SYSTEM ASSOCIATED WITH AGEING ARE KNOWN AS IMMUNOSENESCENCE. THIS IS CHARACTERISED BY A DECLINE IN IMMUNE RESPONSE, CHRONIC INFLAMMATION AND AN INCREASED RISK OF AUTOIMMUNE DISEASES. A CHRONIC INFLAMMATORY PROCESS WITH PERSISTENT PRODUCTION OF PROINFLAMMATORY MEDIATORS INCREASES THE RISK FOR MORBIDITY AND MORTALITY RELATED TO AGE, AND HAS BEEN DUBBED 'INFLAMM-AGEING'. IMMUNOSENESCENCE IS ASSOCIATED WITH A DECREASE IN THE NUMBER OF NAIVE T AND B CELLS, NK CELLS AND DISRUPTION OF THE PRO- AND ANTI-INFLAMMATORY BALANCE BY CHANGES IN THE PRODUCTION OF CYTOKINES. IN FACT, AGEING OF THE IMMUNE SYSTEM HAS A COMPLEX NETWORK OF UNDERLYING CAUSES WHICH INCLUDE NOT ONLY NATURAL MECHANISMS OF SENESCENCE BUT ALSO CHRONIC DISORDERS, LIFESTYLE, ENVIRONMENTAL AND EPIGENETIC FACTORS, AND INFECTIONS. MOREOVER, IMMUNOSENESCENCE HAS AN INFLUENCE ON THE COURSE OF CHRONIC DISEASES WHICH HAVE AN ONSET IN YOUNG ADULTS, SUCH AS MULTIPLE SCLEROSIS (MS). CURRENT DISEASE MODIFYING THERAPIES (DMTS) IN MS AIM TO REDUCE THE FREQUENCY OF RELAPSES AND TO SLOW DISEASE PROGRESSION, BUT THEY DO NOT NECESSARILY STOP THE ACCUMULATION OF DISABILITY RELATED TO DISEASE PROGRESSION. SOME FEATURES OF IMMUNOSENESCENCE FOUND IN AGED HEALTHY CONTROLS ARE ALREADY OBSERVED IN MS PATIENTS AT A YOUNGER AGE. THE OLDER POPULATION IS CHARACTERISED BY AN INCREASED SUSCEPTIBILITY TO INFECTIONS, A POOR RESPONSE TO VACCINATIONS, AND A HIGHER RISK OF DEVELOPING CANCER, VASCULAR DISEASES AND NEURODEGENERATION. IMMUNOSENESCENCE IS AN IMPORTANT FACTOR INFLUENCING THE COURSE OF MS, AND THE SAFETY AND EFFECTIVENESS OF DMTS. THE RELATIONSHIP BETWEEN THE PATHOGENIC PROCESS UNDERLYING THE DEVELOPMENT OF MS AND IMMUNOSENESCENCE REQUIRES FURTHER INVESTIGATION. 2022 16 1508 36 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 17 4323 31 MICRORNAS IN PSYCHOLOGICAL STRESS REACTIONS AND THEIR USE AS STRESS-ASSOCIATED BIOMARKERS, ESPECIALLY IN HUMAN SALIVA. MICRORNAS (MIRNAS) PLAY A CENTRAL ROLE IN THE REGULATION OF MANY CELLULAR PROCESSES INCLUDING PHYSIOLOGICAL AND PSYCHOLOGICAL STRESS REACTION PATHWAYS. PSYCHOLOGICAL STRESS IS AN IMPORTANT FACTOR FOR THE GENESIS AND MAINTENANCE OF MANY DISEASES. SEVERAL MIRNAS HAVE ALREADY BEEN DESCRIBED TO BE INVOLVED IN ITS REGULATION. THE PRESENCE OF MIRNAS IN ALL BODY FLUIDS IMPLIES A WIDESPREAD ROLE IN COMMUNICATION THROUGHOUT THE WHOLE ORGANISM AND TOGETHER WITH THEIR STABILITY MAKES THEM FORMIDABLE CANDIDATES AS BIOMARKERS. ALTERATIONS OF STRESS-ASSOCIATED MIRNA EXPRESSION LEVELS HAVE BEEN FOUND IN THE BRAIN AND WHOLE BLOOD OF HUMANS AND ANIMALS. IN THIS PAPER, WE REVIEW THE PARTICIPATION OF MIRNAS IN STRESS-REACTIVE PROCESSES AS WELL AS THEIR USABILITY AS SALIVARY BIOMARKERS OF SUCH PROCESSES. IN CONCLUSION, WE SUGGEST THAT SALIVARY MIRNAS MAY BE USEFUL AS NONINVASIVE BIOMARKERS TO ASSESS EPIGENETIC REGULATION PROCESSES OF CHRONIC OR ACUTE PSYCHOLOGICAL STRESS REACTIONS. 2017 18 4093 31 MATERNAL SEPARATION FOLLOWED BY CHRONIC MILD STRESS IN ADULTHOOD IS ASSOCIATED WITH CONCERTED EPIGENETIC REGULATION OF AP-1 COMPLEX GENES. DEPRESSION IS ONE OF THE MOST PREVALENT MENTAL DISEASES WORLDWIDE. PATIENTS WITH PSYCHIATRIC DISEASES OFTEN HAVE A HISTORY OF CHILDHOOD NEGLECT, INDICATING THAT EARLY-LIFE EXPERIENCES PREDISPOSE TO PSYCHIATRIC DISEASES IN ADULTHOOD. TWO STRONG MODELS WERE USED IN THE PRESENT STUDY: THE MATERNAL SEPARATION/EARLY DEPRIVATION MODEL (MS) AND THE CHRONIC MILD STRESS MODEL (CMS). IN BOTH MODELS, WE FOUND CHANGES IN THE EXPRESSION OF A NUMBER OF GENES SUCH AS CREB AND NPY. STRIKINGLY, THERE WAS A CLEAR REGULATION OF EXPRESSION OF FOUR GENES INVOLVED IN THE AP-1 COMPLEX: C-FOS, C-JUN, FOSB, AND JUN-B. INTERESTINGLY, DIFFERENT EXPRESSION LEVELS WERE OBSERVED DEPENDING ON THE MODEL, WHEREAS THE COMBINATION OF THE MODELS RESULTED IN A NORMAL LEVEL OF GENE EXPRESSION. THE EFFECTS OF MS AND CMS ON GENE EXPRESSION WERE ASSOCIATED WITH DISTINCT HISTONE METHYLATION/ACETYLATION PATTERNS OF ALL FOUR GENES. THE EPIGENETIC CHANGES, LIKE GENE EXPRESSION, WERE ALSO DEPENDENT ON THE SPECIFIC STRESSOR OR THEIR COMBINATION. THE OBTAINED RESULTS SUGGEST THAT SINGLE LIFE EVENTS LEAVE A MARK ON GENE EXPRESSION AND THE EPIGENETIC SIGNATURE OF GENE PROMOTERS, BUT A COMBINATION OF DIFFERENT STRESSORS AT DIFFERENT LIFE STAGES CAN FURTHER CHANGE GENE EXPRESSION THROUGH EPIGENETIC FACTORS, POSSIBLY CAUSING THE LONG-LASTING ADVERSE EFFECTS OF STRESS. 2021 19 5756 27 SOCIOECONOMIC DEPRIVATION, ADVERSE CHILDHOOD EXPERIENCES AND MEDICAL DISORDERS IN ADULTHOOD: MECHANISMS AND ASSOCIATIONS. SEVERE SOCIOECONOMIC DEPRIVATION (SED) AND ADVERSE CHILDHOOD EXPERIENCES (ACE) ARE SIGNIFICANTLY ASSOCIATED WITH THE DEVELOPMENT IN ADULTHOOD OF (I) ENHANCED INFLAMMATORY STATUS AND/OR HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS DYSFUNCTION AND (II) NEUROLOGICAL, NEUROPROGRESSIVE, INFLAMMATORY AND AUTOIMMUNE DISEASES. THE MECHANISMS BY WHICH THESE ASSOCIATIONS TAKE PLACE ARE DETAILED. THE TWO SETS OF CONSEQUENCES ARE THEMSELVES STRONGLY ASSOCIATED, WITH THE FIRST SET LIKELY CONTRIBUTING TO THE SECOND. MECHANISMS ENABLING BIDIRECTIONAL COMMUNICATION BETWEEN THE IMMUNE SYSTEM AND THE BRAIN ARE DESCRIBED, INCLUDING COMPLEX SIGNALLING PATHWAYS FACILITATED BY FACTORS AT THE LEVEL OF IMMUNE CELLS. ALSO DETAILED ARE MECHANISMS UNDERPINNING THE ASSOCIATION BETWEEN SED, ACE AND THE GENESIS OF PERIPHERAL INFLAMMATION, INCLUDING EPIGENETIC CHANGES TO IMMUNE SYSTEM-RELATED GENE EXPRESSION. THE DURATION AND MAGNITUDE OF INFLAMMATORY RESPONSES CAN BE INFLUENCED BY GENETIC FACTORS, INCLUDING SINGLE NUCLEOTIDE POLYMORPHISMS, AND BY EPIGENETIC FACTORS, WHEREBY PRO-INFLAMMATORY CYTOKINES, REACTIVE OXYGEN SPECIES, REACTIVE NITROGEN SPECIES AND NUCLEAR FACTOR-KAPPAB AFFECT GENE DNA METHYLATION AND HISTONE ACETYLATION AND ALSO INDUCE SEVERAL MICRORNAS INCLUDING MIR-155, MIR-181B-1 AND MIR-146A. ADULT HPA AXIS ACTIVITY IS REGULATED BY (I) GENETIC FACTORS, SUCH AS GLUCOCORTICOID RECEPTOR POLYMORPHISMS; (II) EPIGENETIC FACTORS AFFECTING GLUCOCORTICOID RECEPTOR FUNCTION OR EXPRESSION, INCLUDING THE METHYLATION STATUS OF ALTERNATIVE PROMOTER REGIONS OF NR3C1 AND THE METHYLATION OF FKBP5 AND HSD11BETA2; (III) CHRONIC INFLAMMATION AND CHRONIC NITROSATIVE AND OXIDATIVE STRESS. FINALLY, IT IS SHOWN HOW SEVERE PSYCHOLOGICAL STRESS ADVERSELY AFFECTS MITOCHONDRIAL STRUCTURE AND FUNCTIONING AND IS ASSOCIATED WITH CHANGES IN BRAIN MITOCHONDRIAL DNA COPY NUMBER AND TRANSCRIPTION; MITOCHONDRIA CAN ACT AS COURIERS OF CHILDHOOD STRESS INTO ADULTHOOD. 2019 20 3137 32 GLOBAL DNA METHYLATION PROFILING OF MANGANESE-EXPOSED HUMAN NEUROBLASTOMA SH-SY5Y CELLS REVEALS EPIGENETIC ALTERATIONS IN PARKINSON'S DISEASE-ASSOCIATED GENES. MANGANESE (MN) IS AN ESSENTIAL TRACE ELEMENT REQUIRED FOR OPTIMAL FUNCTIONING OF CELLULAR BIOCHEMICAL PATHWAYS IN THE CENTRAL NERVOUS SYSTEM. ELEVATED EXPOSURE TO MN THROUGH ENVIRONMENTAL AND OCCUPATIONAL EXPOSURE CAN CAUSE NEUROTOXIC EFFECTS RESULTING IN MANGANISM, A CONDITION WITH CLINICAL SYMPTOMS IDENTICAL TO IDIOPATHIC PARKINSON'S DISEASE. EPIGENETICS IS NOW RECOGNIZED AS A BIOLOGICAL MECHANISM INVOLVED IN THE ETIOLOGY OF VARIOUS DISEASES. HERE, WE INVESTIGATED THE ROLE OF DNA METHYLATION ALTERATIONS INDUCED BY CHRONIC MN (100 MICROM) EXPOSURE IN HUMAN NEUROBLASTOMA (SH-SY5Y) CELLS IN RELEVANCE TO PARKINSON'S DISEASE. A COMBINED ANALYSIS OF DNA METHYLATION AND GENE EXPRESSION DATA FOR PARKINSON'S DISEASE-ASSOCIATED GENES WAS CARRIED OUT. WHOLE-GENOME BISULFITE CONVERSION AND SEQUENCING INDICATE EPIGENETIC PERTURBATION OF KEY GENES INVOLVED IN BIOLOGICAL PROCESSES ASSOCIATED WITH NEURONAL CELL HEALTH. INTEGRATION OF DNA METHYLATION DATA WITH GENE EXPRESSION REVEALS EPIGENETIC ALTERATIONS TO PINK1, PARK2 AND TH GENES THAT PLAY CRITICAL ROLES IN THE ONSET OF PARKINSONISM. THE PRESENT STUDY SUGGESTS THAT MN-INDUCED ALTERATION OF DNA METHYLATION OF PINK1-PARK2 MAY INFLUENCE MITOCHONDRIAL FUNCTION AND PROMOTE PARKINSONISM. OUR FINDINGS PROVIDE A BASIS TO FURTHER EXPLORE AND VALIDATE THE EPIGENETIC BASIS OF MN-INDUCED NEUROTOXICITY . 2017