1 3974 146 LONG-TERM CADMIUM EXPOSURE IMPAIRS COGNITIVE FUNCTION BY ACTIVATING LNC-GM10532/M6A/FIS1 AXIS-MEDIATED MITOCHONDRIAL FISSION AND DYSFUNCTION. CADMIUM (CD), A UBIQUITOUS ENVIRONMENTAL CONTAMINANT, IS DEEMED A POSSIBLE AETIOLOGICAL CAUSE OF COGNITIVE DISORDERS IN HUMANS. NEVERTHELESS, THE EXACT MECHANISM BY WHICH CHRONIC EXPOSURE TO CD CAUSES NEUROTOXICITY IS NOT FULLY UNDERSTOOD. IN THIS STUDY, MOUSE NEUROBLASTOMA CELLS (NEURO-2A CELLS) AND PRIMARY HIPPOCAMPAL NEURONS WERE EXPOSED TO LOW-DOSE (1, 2, AND 4 MUM FOR NEURO-2A CELLS OR 0.5, 1, AND 1.5 MUM FOR HIPPOCAMPAL NEURONS) CADMIUM CHLORIDE (CDCL(2)) FOR 72 H (H), AND MALE MICE (C57BL/6J, 8 WEEKS) WERE ORALLY ADMINISTERED CDCL(2) (0.6 MG/L, APPROXIMATELY EQUAL TO 2.58 MUG/KG.BW/D) FOR 6 MONTHS TO INVESTIGATE THE EFFECTS AND MECHANISM OF CHRONIC CD-INDUCED NEUROTOXICITY. HERE, CHRONIC EXPOSURE TO CD IMPAIRED MITOCHONDRIAL FUNCTION BY PROMOTING EXCESS REACTIVE OXYGEN SPECIES (ROS) PRODUCTION, ALTERING MITOCHONDRIAL MEMBRANE POTENTIAL (DELTAPSIM) AND REDUCING ADENOSINE TRIPHOSPHATE (ATP) CONTENT, CONTRIBUTING TO NEURONAL CELL DEATH. SPECIFICALLY, MICROARRAY ANALYSIS REVEALED THAT THE LONG NONCODING RNA GM10532 (LNC-GM10532) WAS MOST HIGHLY EXPRESSED IN NEURO-2A CELLS EXPOSED TO 4 MUM CDCL(2) FOR 72 H COMPARED WITH CONTROLS, AND INHIBITION OF LNC-GM10532 SIGNIFICANTLY ANTAGONIZED CDCL(2)-INDUCED MITOCHONDRIAL DYSFUNCTION AND NEUROTOXICITY. MECHANISTICALLY, LNC-GM10532 INCREASED FISSION 1 (FIS1) EXPRESSION AND MITOCHONDRIAL FISSION BY RECRUITING THE M6A WRITER METHYLTRANSFERASE-LIKE 14 (METTL14) AND ENHANCING M6A MODIFICATION OF FIS1 MRNA. MOREOVER, LNC-GM10532 WAS ALSO REQUIRED FOR CHRONIC CD-INDUCED MITOCHONDRIAL DYSFUNCTION AND MEMORY DEFICITS IN A RODENT MODEL. THEREFORE, DATA OF THIS STUDY REVEAL A NEW EPIGENETIC MECHANISM OF CHRONIC CD NEUROTOXICITY. 2023 2 5205 27 PRENATAL STRESS CHANGES THE GLYCOPROTEIN GPM6A GENE EXPRESSION AND INDUCES EPIGENETIC CHANGES IN RAT OFFSPRING BRAIN. PRENATAL STRESS (PS) EXERTS STRONG IMPACT ON FETAL BRAIN DEVELOPMENT AND ON ADULT OFFSPRING BRAIN FUNCTIONS. PREVIOUS WORK DEMONSTRATED THAT CHRONIC STRESS ALTERS THE MRNA EXPRESSION OF GPM6A, A NEURONAL GLYCOPROTEIN INVOLVED IN FILOPODIUM EXTENSION. IN THIS WORK, WE ANALYZED THE EFFECT OF PS ON GPM6A EXPRESSION AND THE EPIGENETIC MECHANISMS INVOLVED. PREGNANT WISTAR RATS RECEIVED RESTRAINT STRESS DURING THE LAST WEEK OF GESTATION. MALE OFFSPRING WERE SACRIFICED ON POSTNATAL DAYS 28 AND 60. HIPPOCAMPUS AND PREFRONTAL CORTEX SAMPLES WERE ANALYZED FOR GENE EXPRESSION (QPCR FOR MRNAS AND MICRORNAS), METHYLATION STATUS (BISULFITE CONVERSION) AND PROTEIN LEVELS. HIPPOCAMPAL NEURONS IN CULTURE WERE USED TO ANALYZE MICRORNA OVEREXPRESSION EFFECTS. PRENATAL STRESS INDUCED CHANGES IN GPM6A LEVELS IN BOTH TISSUES AND AT BOTH AGES ANALYZED, INDICATING A PERSISTENT EFFECT. TWO CPG ISLANDS IN THE GPM6A GENE WERE IDENTIFIED. VARIATIONS IN THE METHYLATION PATTERN AT THREE SPECIFIC CPGS WERE FOUND IN HIPPOCAMPUS, BUT NOT IN PFC SAMPLES FROM PS OFFSPRING. MICRORNAS PREDICTED TO TARGET GPM6A WERE IDENTIFIED IN SILICO. QPCR MEASUREMENTS SHOWED THAT PS MODIFIED THE EXPRESSION OF SEVERAL MICRORNAS IN BOTH TISSUES, BEING MICRORNA-133B THE MOST SIGNIFICANTLY ALTERED. FURTHER STUDIES OVEREXPRESSING THIS MICRORNA IN NEURONAL CULTURES SHOWED A REDUCTION IN GMP6A MRNA AND PROTEIN LEVEL. MOREOVER FILOPODIUM DENSITY WAS ALSO REDUCED, SUGGESTING THAT GPM6A FUNCTION WAS AFFECTED. GESTATIONAL STRESS AFFECTED GPM6A GENE EXPRESSION IN OFFSPRING LIKELY THROUGH CHANGES IN METHYLATION STATUS AND IN POSTTRANSCRIPTIONAL REGULATION BY MICRORNAS. THUS, OUR FINDINGS PROPOSE GPM6A AS A NOVEL TARGET FOR EPIGENETIC REGULATION DURING PRENATAL STRESS. 2014 3 984 33 CHRONIC PSYCHOLOGICAL STRESS ALTERS GENE EXPRESSION IN RAT COLON EPITHELIAL CELLS PROMOTING CHROMATIN REMODELING, BARRIER DYSFUNCTION AND INFLAMMATION. CHRONIC STRESS IS COMMONLY ASSOCIATED WITH ENHANCED ABDOMINAL PAIN (VISCERAL HYPERSENSITIVITY), BUT THE CELLULAR MECHANISMS UNDERLYING HOW CHRONIC STRESS INDUCES VISCERAL HYPERSENSITIVITY ARE POORLY UNDERSTOOD. IN THIS STUDY, WE EXAMINED CHANGES IN GENE EXPRESSION IN COLON EPITHELIAL CELLS FROM A RAT MODEL USING RNA-SEQUENCING TO EXAMINE STRESS-INDUCED CHANGES TO THE TRANSCRIPTOME. FOLLOWING CHRONIC STRESS, THE MOST SIGNIFICANTLY UP-REGULATED GENES INCLUDED ATG16L1, COQ10B, DCAF13, NAT2, PTBP2, RRAS2, SPINK4 AND DOWN-REGULATED GENES INCLUDING ABAT, CITED2, CNNM2, DAB2IP, PLEKHM1, SCD2, AND TAB2. THE PRIMARY ALTERED BIOLOGICAL PROCESSES REVEALED BY NETWORK ENRICHMENT ANALYSIS WERE INFLAMMATION/IMMUNE RESPONSE, TISSUE MORPHOGENESIS AND DEVELOPMENT, AND NUCLEOSOME/CHROMATIN ASSEMBLY. THE MOST SIGNIFICANTLY DOWN-REGULATED PROCESS WAS THE DIGESTIVE SYSTEM DEVELOPMENT/FUNCTION, WHEREAS THE MOST SIGNIFICANTLY UP-REGULATED PROCESSES WERE INFLAMMATORY RESPONSE, ORGANISMAL INJURY, AND CHROMATIN REMODELING MEDIATED BY H3K9 METHYLATION. FURTHERMORE, A SUBPOPULATION OF STRESSED RATS DEMONSTRATED VERY SIGNIFICANTLY ALTERED GENE EXPRESSION AND TRANSCRIPT ISOFORMS, ENRICHED FOR THE DIFFERENTIAL EXPRESSION OF GENES INVOLVED IN THE INFLAMMATORY RESPONSE, INCLUDING UPREGULATION OF CYTOKINE AND CHEMOKINE RECEPTOR GENE EXPRESSION COUPLED WITH DOWNREGULATION OF EPITHELIAL ADHERENS AND TIGHT JUNCTION MRNAS. IN SUMMARY, THESE FINDINGS SUPPORT THAT CHRONIC STRESS IS ASSOCIATED WITH INCREASED LEVELS OF CYTOKINES AND CHEMOKINES, THEIR DOWNSTREAM SIGNALING PATHWAYS COUPLED TO DYSREGULATION OF INTESTINAL CELL DEVELOPMENT AND FUNCTION. EPIGENETIC REGULATION OF CHROMATIN REMODELING LIKELY PLAYS A PROMINENT ROLE IN THIS PROCESS. RESULTS ALSO SUGGEST THAT SUPER ENHANCERS PLAY A PRIMARY ROLE IN CHRONIC STRESS-ASSOCIATED INTESTINAL BARRIER DYSFUNCTION. 2022 4 3468 36 HYPOXIA-INDUCED DNA HYPERMETHYLATION IN HUMAN PULMONARY FIBROBLASTS IS ASSOCIATED WITH THY-1 PROMOTER METHYLATION AND THE DEVELOPMENT OF A PRO-FIBROTIC PHENOTYPE. BACKGROUND: PULMONARY FIBROSIS IS A DEBILITATING AND LETHAL DISEASE WITH NO EFFECTIVE TREATMENT OPTIONS. UNDERSTANDING THE PATHOLOGICAL PROCESSES AT PLAY WILL DIRECT THE APPLICATION OF NOVEL THERAPEUTIC AVENUES. HYPOXIA HAS BEEN IMPLICATED IN THE PATHOGENESIS OF PULMONARY FIBROSIS YET THE PRECISE MECHANISM BY WHICH IT CONTRIBUTES TO DISEASE PROGRESSION REMAINS TO BE FULLY ELUCIDATED. IT HAS BEEN SHOWN THAT CHRONIC HYPOXIA CAN ALTER DNA METHYLATION PATTERNS IN TUMOUR-DERIVED CELL LINES. THIS EPIGENETIC ALTERATION CAN INDUCE CHANGES IN CELLULAR PHENOTYPE WITH PROMOTER METHYLATION BEING ASSOCIATED WITH GENE SILENCING. OF PARTICULAR RELEVANCE TO IDIOPATHIC PULMONARY FIBROSIS (IPF) IS THE OBSERVATION THAT THY-1 PROMOTER METHYLATION IS ASSOCIATED WITH A MYOFIBROBLAST PHENOTYPE WHERE LOSS OF THY-1 OCCURS ALONGSIDE INCREASED ALPHA SMOOTH MUSCLE ACTIN (ALPHA-SMA) EXPRESSION. THE INITIAL AIM OF THIS STUDY WAS TO DETERMINE WHETHER HYPOXIA REGULATES DNA METHYLATION IN NORMAL HUMAN LUNG FIBROBLASTS (CCD19LU). AS IT HAS BEEN REPORTED THAT HYPOXIA SUPPRESSES THY-1 EXPRESSION DURING LUNG DEVELOPMENT WE ALSO STUDIED THE EFFECT OF HYPOXIA ON THY-1 PROMOTER METHYLATION AND GENE EXPRESSION. METHODS: CCD19LU WERE GROWN FOR UP TO 8 DAYS IN HYPOXIA AND ASSESSED FOR GLOBAL CHANGES IN DNA METHYLATION USING FLOW CYTOMETRY. REAL-TIME PCR WAS USED TO QUANTIFY EXPRESSION OF THY-1, ALPHA-SMA, COLLAGEN I AND III. GENOMIC DNA WAS BISULPHITE TREATED AND METHYLATION SPECIFIC PCR (MSPCR) WAS USED TO EXAMINE THE METHYLATION STATUS OF THE THY-1 PROMOTER. RESULTS: SIGNIFICANT GLOBAL HYPERMETHYLATION WAS DETECTED IN HYPOXIC FIBROBLASTS RELATIVE TO NORMOXIC CONTROLS AND WAS ACCOMPANIED BY INCREASED EXPRESSION OF MYOFIBROBLAST MARKERS. THY-1 MRNA EXPRESSION WAS SUPPRESSED IN HYPOXIC CELLS, WHICH WAS RESTORED WITH THE DEMETHYLATING AGENT 5-AZA-2'-DEOXYCYTIDINE. MSPCR REVEALED THAT THY-1 BECAME METHYLATED FOLLOWING FIBROBLAST EXPOSURE TO 1% O2. CONCLUSION: THESE DATA SUGGEST THAT GLOBAL AND GENE-SPECIFIC CHANGES IN DNA METHYLATION MAY PLAY AN IMPORTANT ROLE IN FIBROBLAST FUNCTION IN HYPOXIA. 2012 5 2032 35 EPIGENETIC CHANGES IN P21 EXPRESSION IN RENAL CELLS AFTER EXPOSURE TO BROMATE. THIS STUDY TESTED THE HYPOTHESIS THAT BROMATE (KBRO3)-INDUCED RENAL CELL DEATH IS MEDIATED BY EPIGENETIC MECHANISMS. GLOBAL DNA METHYLATION, AS ASSESSED BY 5-METHYLCYTOSINE STAINING, WAS NOT CHANGED IN NORMAL RAT KIDNEY CELLS TREATED WITH ACUTE CYTOTOXIC DOSES OF KBRO3 (100 AND 200 PPM), AS COMPARED WITH CONTROLS. HOWEVER, KBRO3 TREATMENT DID INCREASE P38, P53 AND HISTONE 2AX (H2AX) PHOSPHORYLATION, AND P21 EXPRESSION. TREATMENT OF CELLS WITH INHIBITORS OF DNA METHYLTRANSFERASE (5-AZACYTIDINE OR 5-AZA) AND HISTONE DEACETYLASE (TRICHOSTATIN A OR TSA) IN ADDITION TO KBRO3 INCREASED CYTOTOXICITY, AS COMPARED WITH CELLS EXPOSED TO KBRO3 ALONE. 5-AZA AND TSA CO-TREATMENT DID NOT ALTER P38 OR P53 PHOSPHORYLATION, BUT SLIGHTLY DECREASED H2AX PHOSPHORYLATION AND SIGNIFICANTLY DECREASED P21 EXPRESSION. WE ALSO ASSESSED EPIGENETIC CHANGES IN CELLS TREATED UNDER SUB-CHRONIC CONDITIONS WITH ENVIRONMENTALLY RELEVANT CONCENTRATIONS OF KBRO3. UNDER THESE CONDITIONS (0-10PPM KBRO3 FOR UP TO 18 DAYS), WE DETECTED NO INCREASES IN CELL DEATH OR DNA DAMAGE. IN CONTRAST, SLIGHT ALTERATIONS WERE DETECTED IN THE PHOSPHORYLATION OF H2AX, P38, AND P53. SUB-CHRONIC LOW-DOSE KBRO3 TREATMENT ALSO INDUCED A BIPHASIC RESPONSE IN P21 EXPRESSION, WITH LOWER CONCENTRATIONS INCREASING EXPRESSION, BUT HIGHER CONCENTRATIONS DECREASING EXPRESSION. METHYLATION-SPECIFIC PCR DEMONSTRATED THAT SUB-CHRONIC KBRO3 TREATMENT ALTERED THE METHYLATION OF CYTOSINE BASES IN THE P21 GENE, AS COMPARED WITH CONTROLS, CORRELATING TO ALTERATIONS IN P21 PROTEIN EXPRESSION. COLLECTIVELY, THESE DATA SHOW THE NOVEL FINDING THAT KBRO3-INDUCED RENAL CELL DEATH IS ALTERED BY INHIBITORS OF EPIGENETIC MODIFYING ENZYMES AND THAT KBRO3 ITSELF INDUCES EPIGENETIC CHANGES IN THE P21 GENE. 2014 6 2886 25 GABA-AALPHA5 MIGHT BE INVOLVED IN LEARNING-MEMORY DYSFUNCTION IN THE OFFSPRINGS OF CHRONIC ETHANOL-TREATED RATS VIA GABA-AALPHA5 HISTONE H3K9 ACETYLATION. RECENTLY, NUMEROUS STUDIES HAVE BEEN FOCUSED ON THE RELATIONSHIP BETWEEN GABA-A RECEPTORS AND ALCOHOL-INDUCED SPATIAL LEARNING AND MEMORY DEFICITS. GABA-AALPHA5, A SUBUNIT OF GABA-A RECEPTORS, IS CONSIDERED TO PLAY AN IMPORTANT ROLE IN ALCOHOL-INDUCED COGNITIVE IMPAIRMENT, HOWEVER, THE MECHANISM REMAINS OBSCURE. IN THIS STUDY, WE FOUND THAT THE EXPRESSION OF GABA-AALPHA5 INCREASED IN RATS TREATED WITH CHRONIC ETHANOL VIA HISTONE H3K9 ACETYLATION. FURTHERMORE, THIS EPIGENETIC MODIFICATION COULD BE INHERITED BY THE NEXT GENERATIONS, WHICH EVENTUALLY EXHIBIT SIMILAR SPATIAL LEARNING AND MEMORY DEFICITS IN THE OFFSPRINGS. IN SUMMARY, OUR RESULTS SUGGESTED THAT GABA-AALPHA5 MIGHT BE INVOLVED IN CHRONIC ETHANOL TREATMENT-INDUCED LEARNING-MEMORY DYSFUNCTION AND FOR THE FIRST TIME PROVED THAT LEARNING-MEMORY DYSFUNCTION COULD BE INHERITED BY THE OFFSPRINGS VIA HISTONE H3K9 ACETYLATION. HOPEFULLY, IN THE NEAR FUTURE, GABA-AALPHA5 INHIBITORS WOULD BE AN EFFECTIVE WAY TO TREAT ALCOHOL-INDUCED COGNITION IMPAIRMENT. 2019 7 1182 35 CONVERGING AND DIFFERENTIAL BRAIN PHOSPHOLIPID DYSREGULATION IN THE PATHOGENESIS OF REPETITIVE MILD TRAUMATIC BRAIN INJURY AND ALZHEIMER'S DISEASE. REPETITIVE MILD TRAUMATIC BRAIN INJURY (RMTBI) IS A MAJOR EPIGENETIC RISK FACTOR FOR ALZHEIMER'S DISEASE (AD). THE PRECISE NATURE OF HOW RMTBI LEADS TO OR PRECIPITATES AD PATHOLOGY IS CURRENTLY UNKNOWN. NUMEROUS NEUROLOGICAL CONDITIONS HAVE SHOWN AN IMPORTANT ROLE FOR DYSFUNCTIONAL PHOSPHOLIPID METABOLISM AS A DRIVING FACTOR FOR THE PATHOGENESIS OF NEURODEGENERATIVE DISEASES. HOWEVER, THE PRECISE ROLE IN RMTBI AND AD REMAINS ELUSIVE. WE HYPOTHESIZED THAT A DETAILED PHOSPHOLIPID CHARACTERIZATION WOULD REVEAL PROFILES OF RESPONSE TO INJURY IN TBI THAT OVERLAP WITH AGE-DEPENDENT CHANGES IN AD AND THUS PROVIDE INSIGHTS INTO THE TBI-AD RELATIONSHIP. WE EMPLOYED A LIPIDOMIC APPROACH EXAMINING BRAIN PHOSPHOLIPID PROFILES FROM MOUSE MODELS OF RMTBI AND AD. CORTEX AND HIPPOCAMPAL TISSUE WERE COLLECTED AT 24 H, 3, 6, 9, AND 12 MONTHS POST-RMTBI, AND AT AGES REPRESENTING 'PRE', 'PERI' AND 'POST' ONSET OF AMYLOID PATHOLOGY (I.E., 3, 9, 15 MONTHS-OLD). TOTAL LEVELS OF PHOSPHATIDYLCHOLINE (PC), PHOSPHATIDYLETHANOLAMINE (PE), LYSOPE, AND PHOSPHATIDYLINOSITOL (PI), INCLUDING THEIR MONOUNSATURATED, POLYUNSATURATED AND SATURATED FATTY ACID (FA) CONTAINING SPECIES WERE SIGNIFICANTLY INCREASED AT ACUTE AND/OR CHRONIC TIME POINTS POST-INJURY IN BOTH BRAIN REGIONS. HOWEVER, LEVELS OF MOST PHOSPHOLIPID SPECIES IN PS1/APP MICE WERE NOMINAL IN THE HIPPOCAMPUS, WHILE IN THE CORTEX, LEVELS WERE SIGNIFICANTLY DECREASED AT AGES POST-ONSET OF AMYLOID PATHOLOGY. SPHINGOMYELIN AND LYSOPC LEVELS SHOWED COINCIDENTAL TRENDS IN OUR RMTBI AND AD MODELS WITHIN THE HIPPOCAMPUS, AN INCREASE AT ACUTE AND/OR CHRONIC TIME POINTS EXAMINED. THE RATIO OF ARACHIDONIC ACID (OMEGA-6 FA) TO DOCOSAHEXAENOIC ACID (OMEGA-3 FA)-CONTAINING PE SPECIES WAS INCREASED AT EARLY TIME POINTS IN THE HIPPOCAMPUS OF INJURED VERSUS SHAM MICE, AND IN PS1/APP MICE THERE WAS A COINCIDENTAL INCREASE COMPARED TO WILD TYPE LITTERMATES AT ALL TIME POINTS. THIS STUDY DEMONSTRATES SOME OVERLAPPING AND DIVERSE PHOSPHOLIPID PROFILES IN RMTBI AND AD MODELS. FUTURE STUDIES ARE REQUIRED TO CORROBORATE OUR FINDINGS IN HUMAN POST-MORTEM TISSUE. INVESTIGATION OF SECONDARY MECHANISMS TRIGGERED BY ABERRANT DOWNSTREAM ALTERATIONS IN BIOACTIVE METABOLITES OF THESE PHOSPHOLIPIDS, AND THEIR MODULATION AT THE APPROPRIATE TIME-WINDOWS OF OPPORTUNITY COULD HELP FACILITATE DEVELOPMENT OF NOVEL THERAPEUTIC STRATEGIES TO AMELIORATE THE NEURODEGENERATIVE CONSEQUENCES OF RMTBI OR THE POTENTIAL TRIGGERING OF AD PATHOGENESIS BY RMTBI. 2019 8 2246 27 EPIGENETIC MODULATION OF INFLAMMATION AND SYNAPTIC PLASTICITY PROMOTES RESILIENCE AGAINST STRESS IN MICE. MAJOR DEPRESSIVE DISORDER IS ASSOCIATED WITH ABNORMALITIES IN THE BRAIN AND THE IMMUNE SYSTEM. CHRONIC STRESS IN ANIMALS SHOWED THAT EPIGENETIC AND INFLAMMATORY MECHANISMS PLAY IMPORTANT ROLES IN MEDIATING RESILIENCE AND SUSCEPTIBILITY TO DEPRESSION. HERE, THROUGH A HIGH-THROUGHPUT SCREENING, WE IDENTIFY TWO PHYTOCHEMICALS, DIHYDROCAFFEIC ACID (DHCA) AND MALVIDIN-3'-O-GLUCOSIDE (MAL-GLUC) THAT ARE EFFECTIVE IN PROMOTING RESILIENCE AGAINST STRESS BY MODULATING BRAIN SYNAPTIC PLASTICITY AND PERIPHERAL INFLAMMATION. DHCA/MAL-GLUC ALSO SIGNIFICANTLY REDUCES DEPRESSION-LIKE PHENOTYPES IN A MOUSE MODEL OF INCREASED SYSTEMIC INFLAMMATION INDUCED BY TRANSPLANTATION OF HEMATOPOIETIC PROGENITOR CELLS FROM STRESS-SUSCEPTIBLE MICE. DHCA REDUCES PRO-INFLAMMATORY INTERLEUKIN 6 (IL-6) GENERATIONS BY INHIBITING DNA METHYLATION AT THE CPG-RICH IL-6 SEQUENCES INTRONS 1 AND 3, WHILE MAL-GLUC MODULATES SYNAPTIC PLASTICITY BY INCREASING HISTONE ACETYLATION OF THE REGULATORY SEQUENCES OF THE RAC1 GENE. PERIPHERAL INFLAMMATION AND SYNAPTIC MALADAPTATION ARE IN LINE WITH NEWLY HYPOTHESIZED CLINICAL INTERVENTION TARGETS FOR DEPRESSION THAT ARE NOT ADDRESSED BY CURRENTLY AVAILABLE ANTIDEPRESSANTS. 2018 9 491 28 ASSESSING THE IMPACT OF POLYETHYLENE NANO/MICROPLASTIC EXPOSURE ON HUMAN VAGINAL KERATINOCYTES. THE GLOBAL RISE OF SINGLE-USE THROW-AWAY PLASTIC PRODUCTS HAS ELICITED A MASSIVE INCREASE IN THE NANO/MICROPLASTICS (N/MPLS) EXPOSURE BURDEN IN HUMANS. RECENTLY, IT HAS BEEN DEMONSTRATED THAT DISPOSABLE PERIOD PRODUCTS MAY RELEASE N/MPLS WITH USAGE, WHICH REPRESENTS A POTENTIAL THREAT TO WOMEN'S HEALTH WHICH HAS NOT BEEN SCIENTIFICALLY ADDRESSED YET. BY USING POLYETHYL ENE (PE) PARTICLES (200 NM TO 9 MUM), WE SHOWED THAT ACUTE EXPOSURE TO A HIGH CONCENTRATION OF N/MPLS INDUCED CELL TOXICITY IN VAGINAL KERATINOCYTES AFTER EFFECTIVE CELLULAR UPTAKE, AS VIABILITY AND APOPTOSIS DATA SUGGEST, ALONG WITH TRANSMISSION ELECTRON MICROSCOPY (TEM) OBSERVATIONS. THE INTERNALISED N/MPLS ALTERED THE EXPRESSION OF JUNCTIONAL AND ADHERENCE PROTEINS AND THE ORGANISATION OF THE ACTIN CORTEX, INFLUENCING THE LEVEL OF GENES INVOLVED IN OXIDATIVE STRESS SIGNALLING PATHWAYS AND THAT OF MIRNAS RELATED TO EPITHELIAL BARRIER FUNCTION. WHEN THE EXPOSURE TO PE N/MPLS WAS DISCONTINUED OR BECAME CHRONIC, CELLS WERE ABLE TO RECOVER FROM THE NEGATIVE EFFECTS ON VIABILITY AND DIFFERENTIATION/PROLIFERATION GENE EXPRESSION IN A FEW DAYS. HOWEVER, IN ALL CASES, PE N/MPL EXPOSURE PROMPTED A SUSTAINED ALTERATION OF DNA METHYLTRANSFERASE AND DNA DEMETHYLASE EXPRESSION, WHICH MIGHT IMPACT EPIGENETIC REGULATION PROCESSES, LEADING TO ACCELERATED CELL AGEING AND INFLAMMATION, OR THE OCCURRENCE OF MALIGNANT TRANSFORMATION. 2023 10 3390 27 HOPX PLAYS A CRITICAL ROLE IN ANTIRETROVIRAL DRUGS INDUCED EPIGENETIC MODIFICATION AND CARDIAC HYPERTROPHY. PEOPLE LIVING WITH HIV (PLWH) HAVE TO TAKE AN ANTIRETROVIRAL THERAPY (ART) FOR LIFE AND SHOW NONCOMMUNICABLE ILLNESSES SUCH AS CHRONIC INFLAMMATION, IMMUNE ACTIVATION, AND MULTIORGAN DYSREGULATION. RECENT STUDIES SUGGEST THAT LONG-TERM USE OF ART INDUCES COMORBID CONDITIONS AND IS ONE OF THE LEADING CAUSES OF HEART FAILURE IN PLWH. HOWEVER, THE MOLECULAR MECHANISM OF ANTIRETROVIRAL DRUGS (ARVS) INDUCED HEART FAILURE IS UNCLEAR. TO DETERMINE THE MECHANISM OF ARVS INDUCED CARDIAC DYSFUNCTION, WE PERFORMED GLOBAL TRANSCRIPTOMIC PROFILING OF ARVS TREATED NEONATAL RAT VENTRICULAR CARDIOMYOCYTES IN CULTURE. DIFFERENTIALLY EXPRESSED GENES WERE IDENTIFIED BY RNA-SEQUENCING. OUR DATA SHOW THAT ARVS TREATMENT CAUSES UPREGULATION OF SEVERAL BIOLOGICAL FUNCTIONS ASSOCIATED WITH CARDIOTOXICITY, HYPERTROPHY, AND HEART FAILURE. GLOBAL GENE EXPRESSION DATA WERE VALIDATED IN CARDIAC TISSUE ISOLATED FROM HIV PATIENTS HAVING A HISTORY OF ART. INTERESTINGLY, WE FOUND THAT HOMEODOMAIN-ONLY PROTEIN HOMEOBOX (HOPX) EXPRESSION WAS SIGNIFICANTLY INCREASED IN CARDIOMYOCYTES TREATED WITH ARVS AND IN THE HEART TISSUE OF HIV PATIENTS. FURTHERMORE, WE FOUND THAT HOPX PLAYS A CRUCIAL ROLE IN ARVS MEDIATED CELLULAR HYPERTROPHY. MECHANISTICALLY, WE FOUND THAT HOPX PLAYS A CRITICAL ROLE IN EPIGENETIC REGULATION, THROUGH DEACETYLATION OF HISTONE, WHILE THE HDAC INHIBITOR, TRICHOSTATIN A, CAN RESTORE THE ACETYLATION LEVEL OF HISTONE 3 IN THE PRESENCE OF ARVS. 2021 11 3049 30 GENOME-WIDE ANALYSIS REVEALS ZINC TRANSPORTER ZIP9 REGULATED BY DNA METHYLATION PROMOTES RADIATION-INDUCED SKIN FIBROSIS VIA THE TGF-BETA SIGNALING PATHWAY. RADIATION-INDUCED SKIN FIBROSIS IS A DETRIMENTAL AND CHRONIC DISORDER THAT OCCURS AFTER RADIATION EXPOSURE. DNA METHYLATION HAS BEEN CHARACTERIZED AS AN IMPORTANT REGULATORY MECHANISM OF MULTIPLE PATHOLOGICAL PROCESSES. IN THIS STUDY, WE COMPARED THE GENOME-WIDE DNA METHYLATION STATUS IN RADIATION-INDUCED FIBROTIC SKIN AND ADJACENT NORMAL TISSUES OF RATS BY METHYLATED DNA IMMUNOPRECIPITATION SEQUENCING. RADIATION-INDUCED FIBROTIC SKIN SHOWED DIFFERENTIALLY METHYLATED REGIONS ASSOCIATED WITH 3,650 PROTEIN-CODING GENES, 72 MICRORNAS, 5,836 LONG NONCODING RNAS AND 3 PIWI-INTERACTING RNAS. BY INTEGRATING THE MRNA AND METHYLATION PROFILES, THE ZINC TRANSPORTER SLC39A9/ZIP9 WAS INVESTIGATED IN GREATER DETAIL. THE PROTEIN LEVEL OF ZIP9 WAS INCREASED IN IRRADIATED SKIN TISSUES OF HUMANS, MONKEYS, AND RATS, ESPECIALLY IN RADIOGENIC FIBROTIC SKIN TISSUES. RADIATION INDUCED THE DEMETHYLATION OF A CPG DINUCLEOTIDE IN EXON 1 OF ZIP9 THAT RESULTED IN RECRUITMENT OF THE TRANSCRIPTIONAL FACTOR SP1 AND INCREASED ZIP9 EXPRESSION. OVEREXPRESSION OF ZIP9 RESULTED IN ACTIVATION OF THE PROFIBROTIC TRANSFORMING GROWTH FACTOR-BETA SIGNALING PATHWAY THROUGH PROTEIN KINASE B IN HUMAN FIBROBLASTS. IN ADDITION, RADIATION-INDUCED SKIN FIBROSIS WAS ASSOCIATED WITH INCREASED ZINC ACCUMULATION. THE ZINC CHELATOR N,N,N',N'-TETRAKIS(2-PYRIDYLMETHYL)-1,2-ETHYLENEDIAMINE ABROGATED ZIP9-INDUCED ACTIVATION OF THE TRANSFORMING GROWTH FACTOR-BETA SIGNALING PATHWAY AND ATTENUATED RADIATION-INDUCED SKIN FIBROSIS IN A RAT MODEL. IN SUMMARY, OUR FINDINGS ILLUSTRATE EPIGENETIC REGULATION OF ZIP9 AND ITS CRITICAL ROLE IN PROMOTING RADIATION-INDUCED SKIN FIBROSIS. 2020 12 4580 30 N(6)-METHYLADENOSINE MODIFICATION OF FATTY ACID AMIDE HYDROLASE MESSENGER RNA IN CIRCULAR RNA STAG1-REGULATED ASTROCYTE DYSFUNCTION AND DEPRESSIVE-LIKE BEHAVIORS. BACKGROUND: N(6)-METHYLADENOSINE (M(6)A) IS THE MOST ABUNDANT EPIGENETIC MODIFICATION IN EUKARYOTIC MESSENGER RNAS AND IS ESSENTIAL FOR MULTIPLE RNA PROCESSING EVENTS IN PHYSIOLOGICAL AND PATHOLOGICAL PROCESSES. HOWEVER, PRECISELY HOW M(6)A METHYLATION IS INVOLVED IN MAJOR DEPRESSIVE DISORDER (MDD) IS NOT FULLY UNDERSTOOD. METHODS: CIRCULAR RNA STAG1 (CIRCSTAG1) WAS SCREENED FROM THE HIPPOCAMPUS OF CHRONIC UNPREDICTABLE STRESS-TREATED MICE USING HIGH-THROUGHPUT RNA SEQUENCING. MICROINJECTION OF CIRCSTAG1 LENTIVIRUS INTO THE MOUSE HIPPOCAMPUS WAS USED TO OBSERVE THE ROLE OF CIRCSTAG1 IN DEPRESSION. SUCROSE PREFERENCE, FORCED SWIM, AND TAIL SUSPENSION TESTS WERE PERFORMED TO EVALUATE THE DEPRESSIVE-LIKE BEHAVIORS OF MICE. ASTROCYTE DYSFUNCTION WAS EXAMINED BY GFAP IMMUNOSTAINING AND 3D RECONSTRUCTION. METHYLATED RNA IMMUNOPRECIPITATION SEQUENCE ANALYSIS WAS USED TO IDENTIFY DOWNSTREAM TARGETS OF CIRCSTAG1/ALKBH5 (ALKB HOMOLOG 5) AXIS. CELL COUNTING KIT-8 ASSAY WAS PERFORMED TO EVALUATE ASTROCYTE VIABILITY IN VITRO. RESULTS: CIRCSTAG1 WAS SIGNIFICANTLY DECREASED IN THE CHRONIC UNPREDICTABLE STRESS-TREATED MOUSE HIPPOCAMPUS AND IN PERIPHERAL BLOOD OF PATIENTS WITH MDD. OVEREXPRESSION OF CIRCSTAG1 NOTABLY ATTENUATED ASTROCYTE DYSFUNCTION AND DEPRESSIVE-LIKE BEHAVIORS INDUCED BY CHRONIC UNPREDICTABLE STRESS. FURTHER EXAMINATION INDICATED THAT OVEREXPRESSED CIRCSTAG1 CAPTURED ALKBH5 AND DECREASED THE TRANSLOCATION OF ALKBH5 INTO THE NUCLEUS, LEADING TO INCREASED M(6)A METHYLATION OF FATTY ACID AMIDE HYDROLASE (FAAH) MESSENGER RNA AND DEGRADATION OF FAAH IN ASTROCYTES WITH SUBSEQUENT ATTENUATION OF DEPRESSIVE-LIKE BEHAVIORS AND ASTROCYTE LOSS INDUCED BY CORTICOSTERONE IN VITRO. CONCLUSIONS: OUR FINDINGS DISSECT THE FUNCTIONAL LINK BETWEEN CIRCSTAG1 AND M(6)A METHYLATION IN THE CONTEXT OF MDD, PROVIDING EVIDENCE THAT CIRCSTAG1 MAY BE A NOVEL THERAPEUTIC TARGET FOR MDD. 2020 13 3813 25 INTRAUTERINE GROWTH RESTRICTION INHIBITS EXPRESSION OF EUKARYOTIC ELONGATION FACTOR 2 KINASE, A REGULATOR OF PROTEIN TRANSLATION. NUTRIENT DEPRIVATION SUPPRESSES PROTEIN SYNTHESIS BY BLOCKING PEPTIDE ELONGATION. TRANSCRIPTIONAL UPREGULATION AND ACTIVATION OF EUKARYOTIC ELONGATION FACTOR 2 KINASE (EEF2K) BLOCKS PEPTIDE ELONGATION BY PHOSPHORYLATING EUKARYOTIC ELONGATION FACTOR 2. PREVIOUS STUDIES EXAMINING PLACENTAS FROM INTRAUTERINE GROWTH RESTRICTED (IUGR) NEWBORN INFANTS SHOW DECREASED EEF2K EXPRESSION AND ACTIVITY DESPITE CHRONIC NUTRIENT DEPRIVATION. HOWEVER, THE EFFECT OF IUGR ON HEPATIC EEF2K EXPRESSION IN THE FETUS IS UNKNOWN. WE, THEREFORE, EXAMINED THE TRANSCRIPTIONAL REGULATION OF HEPATIC EEF2K GENE EXPRESSION IN A SPRAGUE-DAWLEY RAT MODEL OF IUGR. WE FOUND DECREASED HEPATIC EEF2K MRNA AND PROTEIN LEVELS IN IUGR OFFSPRING AT BIRTH COMPARED WITH CONTROL, CONSISTENT WITH PREVIOUS PLACENTAL OBSERVATIONS. FURTHERMORE, THE CPG ISLAND WITHIN THE EEF2K PROMOTER DEMONSTRATED INCREASED METHYLATION AT A CRITICAL USF 1/2 TRANSCRIPTION FACTOR BINDING SITE. IN VITRO METHYLATION OF THIS BINDING SITE CAUSED NEAR COMPLETE LOSS OF EEF2K PROMOTER ACTIVITY, DESIGNATING THIS PROMOTER AS METHYLATION SENSITIVE. THE EEF2K PROMOTOR IN IUGR OFFSPRING ALSO LOST THE PROTECTIVE HISTONE COVALENT MODIFICATIONS ASSOCIATED WITH UNMETHYLATED CGIS. IN ADDITION, THE +1 NUCLEOSOME WAS DISPLACED 3' AND RNA POLYMERASE LOADING WAS REDUCED AT THE IUGR EEF2K PROMOTER. OUR FINDINGS PROVIDE EVIDENCE TO EXPLAIN WHY IUGR-INDUCED CHRONIC NUTRIENT DEPRIVATION DOES NOT RESULT IN THE UPREGULATION OF EEF2K GENE TRANSCRIPTION. 2016 14 433 28 ANTIDEPRESSANT TREATMENT IS ASSOCIATED WITH EPIGENETIC ALTERATIONS OF HOMER1 PROMOTER IN A MOUSE MODEL OF CHRONIC DEPRESSION. BACKGROUND: UNDERSTANDING THE NEUROBIOLOGY OF DEPRESSION AND THE MECHANISM OF ACTION OF THERAPEUTIC MEASURES IS CURRENTLY A RESEARCH PRIORITY. WE HAVE SHOWN THAT THE EXPRESSION OF THE SYNAPTIC PROTEIN HOMER1A CORRELATES WITH DEPRESSION-LIKE BEHAVIOR AND ITS INDUCTION IS A COMMON MECHANISM OF ACTION OF DIFFERENT ANTIDEPRESSANT TREATMENTS. HOWEVER, THE MECHANISM OF HOMER1A REGULATION IS STILL UNKNOWN. METHODS: WE COMBINED THE CHRONIC DESPAIR MOUSE MODEL (CDM) OF CHRONIC DEPRESSION WITH DIFFERENT ANTIDEPRESSANT TREATMENTS. DEPRESSION-LIKE BEHAVIOR WAS CHARACTERIZED BY FORCED SWIM AND TAIL SUSPENSION TESTS, AND VIA AUTOMATIC MEASUREMENT OF SUCROSE PREFERENCE IN INTELLICAGE. THE HOMER1 MRNA EXPRESSION AND PROMOTER DNA METHYLATION WERE ANALYZED IN CORTEX AND PERIPHERAL BLOOD BY QRT-PCR AND PYROSEQUENCING. RESULTS: CDM MICE SHOW DECREASED HOMER1A AND HOMER1B/C MRNA EXPRESSION IN CORTEX AND BLOOD SAMPLES, WHILE CHRONIC TREATMENT WITH IMIPRAMINE AND FLUOXETINE OR ACUTE KETAMINE APPLICATION INCREASES THEIR LEVEL ONLY IN THE CORTEX. THE QUANTITATIVE ANALYSES OF THE METHYLATION OF 7 CPG SITES, LOCATED ON THE HOMER1 PROMOTER REGION CONTAINING SEVERAL CRE BINDING SITES, SHOW A SIGNIFICANT INCREASE IN DNA METHYLATION IN THE CORTEX OF CDM MICE. IN CONTRAST, ANTIDEPRESSANT TREATMENTS REDUCE THE METHYLATION LEVEL. LIMITATIONS: HOMER1 EXPRESSION AND PROMOTOR METHYLATION WERE NOT ANALYZED IN DIFFERENT BLOOD CELL TYPES. OTHER CPG SITES OF HOMER1 PROMOTER SHOULD BE INVESTIGATED IN FUTURE STUDIES. OUR EXPERIMENTAL APPROACH DOES NOT DISTINGUISH BETWEEN METHYLATION AND HYDROXYMETHYLATION. CONCLUSIONS: WE DEMONSTRATE THAT STRESS-INDUCED DEPRESSION-LIKE BEHAVIOR AND ANTIDEPRESSANT TREATMENTS ARE ASSOCIATED WITH EPIGENETIC ALTERATIONS OF HOMER1 PROMOTER, PROVIDING NEW INSIGHTS INTO THE MECHANISM OF ANTIDEPRESSANT TREATMENT. 2021 15 217 27 ACUTE EXERCISE INCREASES THE EXPRESSION OF KIR2DS4 BY PROMOTER DEMETHYLATION IN NK CELLS. POSITIVE EFFECTS OF EXERCISE ON CANCER PREVENTION AND PROGRESSION HAVE BEEN PROPOSED TO BE MEDIATED BY STIMULATING NATURAL KILLER (NK) CELLS. BECAUSE NK CELL RECEPTORS ARE REGULATED BY EPIGENETIC MODIFICATIONS, WE INVESTIGATED WHETHER ACUTE AEROBIC EXERCISE AND TRAINING CHANGE PROMOTER DNA METHYLATION AND GENE EXPRESSION OF THE ACTIVATING KIR2DS4 AND THE INHIBITING KIR3DL1 GENE. SIXTEEN HEALTHY WOMEN (50-60 YEARS) PERFORMED A GRADED EXERCISE TEST (GXT) AND WERE RANDOMIZED INTO EITHER A PASSIVE CONTROL GROUP OR AN INTERVENTION GROUP PERFORMING A FOUR-WEEK ENDURANCE EXERCISE INTERVENTION. BLOOD SAMPLES (PRE-, POST-GXT AND POST-TRAINING) WERE USED FOR ISOLATION OF DNA/RNA OF NK CELLS TO ASSESS DNA PROMOTER METHYLATION BY TARGETED DEEP-AMPLICON SEQUENCING AND GENE EXPRESSION BY QRT-PCR. POTENTIAL CHANGES IN NK CELL SUBSETS WERE DETERMINED BY FLOW CYTOMETRY. ACUTE AND CHRONIC EXERCISE DID NOT PROVOKE SIGNIFICANT ALTERATIONS OF NK CELL PROPORTIONS. PROMOTER METHYLATION DECREASED AND GENE EXPRESSION INCREASED FOR KIR2DS4 AFTER ACUTE EXERCISE. A HIGH GENE EXPRESSION CORRELATED WITH A LOW METHYLATION OF CPGS THAT WERE ALTERED BY ACUTE EXERCISE. CHRONIC EXERCISE RESULTED IN A MINOR DECREASE OF DNA METHYLATION AND DID NOT ALTER GENE EXPRESSION. ACUTE EXERCISE PROVOKES EPIGENETIC MODIFICATIONS, AFFECTING THE BALANCE BETWEEN THE ACTIVATING KIR2DS4 AND THE INHIBITING KIR3DL1, WITH POTENTIAL BENEFITS ON NK CELL FUNCTION. 2019 16 889 26 CHRONIC DIETARY ADMINISTRATION OF VALPROIC ACID PROTECTS NEURONS OF THE RAT NUCLEUS BASALIS MAGNOCELLULARIS FROM IBOTENIC ACID NEUROTOXICITY. VALPROIC ACID (VPA) HAS BEEN USED FOR MANY YEARS AS A DRUG OF CHOICE FOR EPILEPSY AND MOOD DISORDERS. RECENTLY, EVIDENCE HAS BEEN PROPOSED FOR A WIDE SPECTRUM OF ACTIONS OF THIS DRUG, INCLUDING ANTITUMORAL AND NEUROPROTECTIVE PROPERTIES. VALPROIC ACID-MEDIATED NEUROPROTECTION IN VIVO HAS BEEN SO FAR DEMONSTRATED IN A LIMITED NUMBER OF EXPERIMENTAL MODELS. IN THIS STUDY, WE HAVE TESTED THE NEUROPROTECTIVE POTENTIAL OF CHRONIC (4 + 1 WEEKS) DIETARY ADMINISTRATION OF VPA ON DEGENERATION OF CHOLINERGIC AND GABAERGIC NEURONS OF THE RAT NUCLEUS BASALIS MAGNOCELLULARIS (NBM), INJECTED WITH THE EXCITOTOXIN, IBOTENIC ACID (IBO), AN ANIMAL MODELS THAT IS RELEVANT FOR ALZHEIMER'S DISEASE-LIKE NEURODEGENERATION. WE SHOW THAT VPA TREATMENT SIGNIFICANTLY PROTECTS BOTH CHOLINERGIC AND GABAERGIC NEURONS PRESENT IN THE INJECTED AREA FROM THE EXCITOTOXIC INSULT. A SIGNIFICANT LEVEL OF NEUROPROTECTION, IN PARTICULAR, IS EXERTED TOWARDS THE CHOLINERGIC NEURONS OF THE NBM PROJECTING TO THE CORTEX, AS DEMONSTRATED BY THE SUBSTANTIALLY HIGHER LEVELS OF CHOLINERGIC MARKERS MAINTAINED IN THE TARGET CORTICAL AREA OF VPA-TREATED RATS AFTER IBO INJECTION IN THE NBM. WE FURTHER SHOW THAT CHRONIC VPA ADMINISTRATION RESULTS IN INCREASED ACETYLATION OF HISTONE H3 IN BRAIN, CONSISTENT WITH THE HISTONE DEACETYLASE INHIBITORY ACTION OF VPA AND PUTATIVELY LINKED TO A NEUROPROTECTIVE ACTION OF THE DRUG MEDIATED AT THE EPIGENETIC LEVEL. 2009 17 3465 29 HYPOTHESIS: REGULATION OF NEUROPLASTICITY MAY INVOLVE I-MOTIF AND G-QUADRUPLEX DNA FORMATION MODULATED BY EPIGENETIC MECHANISMS. RECENT STUDIES DEMONSTRATED THE EXISTENCE IN VIVO OF VARIOUS FUNCTIONAL DNA STRUCTURES THAT DIFFER FROM THE DOUBLE HELIX. THE G-QUADRUPLEX (G4) AND INTERCALATED MOTIF (I-MOTIF OR IM) DNA STRUCTURES ARE FORMED AS KNOTS WHERE, CORRESPONDINGLY, GUANINES OR CYTOSINES ON THE SAME STRAND OF DNA BIND TO EACH OTHER. THERE ARE GROUNDS TO BELIEVE THAT G4 AND IM SEQUENCES PLAY A SIGNIFICANT ROLE IN REGULATING GENE EXPRESSION CONSIDERING THEIR TENDENCY TO BE FOUND IN OR NEAR REGULATORY SITES (SUCH AS PROMOTERS, ENHANCERS, AND TELOMERES) AS WELL AS THE CORRELATION BETWEEN THE PREVALENCE OF G4 OR IM CONFORMATIONS AND SPECIFIC PHASES OF CELL CYCLE. NOTABLY, G4 AND IM CAPABLE SEQUENCES TEND TO BE FOUND ON THE OPPOSITE STRANDS OF THE SAME DNA SITE WITH AT MOST ONE OF THE TWO STRUCTURES FORMED AT ANY GIVEN TIME. THE RECENT EVIDENCE THAT K(+), MG(2+) CONCENTRATIONS DIRECTLY AFFECT IM FORMATION (AND LIKELY G4 FORMATION INDIRECTLY) LEAD US TO BELIEVE THAT THESE STRUCTURES MAY PLAY A MAJOR ROLE IN SYNAPTIC PLASTICITY OF NEURONS, AND, THEREFORE, IN A VARIETY OF CENTRAL NERVOUS SYSTEM (CNS) FUNCTIONS INCLUDING MEMORY, LEARNING, HABITUAL BEHAVIORS, PAIN PERCEPTION AND OTHERS. FURTHERMORE, EPIGENETIC MECHANISMS, WHICH HAVE AN IMPORTANT ROLE IN SYNAPTIC PLASTICITY AND MEMORY FORMATION, WERE ALSO SHOWN TO INFLUENCE FORMATION AND STABILITY OF G4S AND IMS. OUR HYPOTHESIS IS THAT NON-CANONICAL DNA AND RNA STRUCTURES COULD BE AN INTEGRAL PART OF NEUROPLASTICITY CONTROL VIA GENE EXPRESSION REGULATION AT THE LEVEL OF TRANSCRIPTION, TRANSLATION AND SPLICING. WE PROPOSE THAT THE REGULATORY ACTIVITY OF DNA IM AND G4 STRUCTURES IS MODULATED BY DNA METHYLATION/DEMETHYLATION OF THE IM AND/OR G4 SEQUENCES, WHICH FACILITATES THE SWITCH BETWEEN CANONICAL AND NON-CANONICAL CONFORMATION. OTHER NEURONAL MECHANISMS INTERACTING WITH THE FORMATION AND REGULATORY ACTIVITY OF NON-CANONICAL DNA AND RNA STRUCTURES, PARTICULARLY G4, IM AND TRIPLEXES, MAY INVOLVE MICRORNAS AS WELL AS ION AND PROTON FLUXES. WE ARE PROPOSING EXPERIMENTS IN ACUTE BRAIN SLICES AND IN VIVO TO TEST OUR HYPOTHESIS. THE PROPOSED STUDIES WOULD PROVIDE NEW INSIGHTS INTO FUNDAMENTAL NEURONAL MECHANISMS IN HEALTH AND DISEASE AND POTENTIALLY OPEN NEW AVENUES FOR TREATING MENTAL HEALTH DISORDERS. 2019 18 272 31 AGE-DEPENDENT DECREASE IN THE INDUCTION OF REGULATORY T CELLS IS ASSOCIATED WITH DECREASED EXPRESSION OF RALDH2 IN MESENTERIC LYMPH NODE DENDRITIC CELLS. A DECLINE IN IMMUNE FUNCTION WITH AGING HAS BEEN REPORTED. REGULATORY T CELL (TREG) INDUCTION IS KNOWN TO DECREASE WITH AGE, AND ELUCIDATING THE UNDERLYING MECHANISM IS IMPORTANT FOR PREVENTING AGE-RELATED DISEASES DUE TO AGE-RELATED CHRONIC INFLAMMATION. IN THE INTESTINE, DENDRITIC CELLS (DCS) PLAY AN IMPORTANT ROLE IN INDUCING TREGS SPECIFIC TO ORAL ANTIGENS, AND THEY EFFICIENTLY INDUCE TREGS VIA PRODUCTION OF RETINOIC ACID (RA), A VITAMIN A METABOLITE, CATALYZED BY THE ENZYME RETINALDEHYDE DEHYDROGENASE 2 (RALDH2). WE HAVE PREVIOUSLY REPORTED THAT IN THE MESENTERIC LYMPH NODE (MLN), A SECONDARY LYMPHOID TISSUE IN WHICH IMMUNE RESPONSES TO ORAL ANTIGENS ARE INDUCED, FOUR DC SUBSETS EXPRESS DIFFERENT LEVELS OF CD11B, CD103, AND PD-L1, AND WE HAVE REPORTED THAT THE CD11B(-)CD103(+)PD-L1(HIGH) SUBSET EXPRESSES THE HIGHEST LEVELS OF THE RALDH2 GENE AND INDUCES TREGS IN VITRO. WE EXAMINED TREG INDUCTION IN YOUNG AND AGED MICE USING A TREG INDUCTION MODEL BY ADMINISTERING A FOOD ANTIGEN, AND WE FOUND THAT ANTIGEN-SPECIFIC TREG INDUCTION WAS DECREASED IN AGED MICE. WE FURTHER INVESTIGATED THE MLN DCS, AND A SIGNIFICANT DECREASE IN RALDH2 GENE EXPRESSION WAS OBSERVED IN MLN DCS FROM AGED MICE. AS FACTORS, WE FOUND THAT THE PROPORTION OF THE CD11B(-)CD103(+)PD-L1(HIGH) SUBSET WAS DECREASED IN AGED MICE COMPARED WITH THAT IN YOUNG MICE AND THAT RALDH ENZYME ACTIVITY WAS DECREASED IN THE CD11B(-)CD103(+)PD-L1(HIGH) AND CD11B(+)CD103(+)PD-L1(HIGH) SUBSETS. FURTHERMORE, ANALYSIS OF THE METHYLATION OF THE RALDH2 GENE PROMOTER REGION REVEALED THAT CPG MOTIFS WERE MORE METHYLATED IN THE MLN DCS OF AGED MICE, SUGGESTING THAT RALDH2 EXPRESSION WAS SUPPRESSED BY EPIGENETIC CHANGES. FINALLY, WE FOUND THAT RA TREATMENT TENDED TO INCREASE TREG INDUCTION. THESE RESULTS SUGGEST THAT THE REGULATION OF RA PRODUCTION MAY BE INVOLVED IN THE AGE-RELATED DECREASE IN ANTIGEN-SPECIFIC TREG INDUCTION. 2020 19 918 28 CHRONIC HYPERGRAVITY INDUCES A MODIFICATION OF HISTONE H3 LYSINE 27 TRIMETHYLATION AT TCRBETA LOCUS IN MURINE THYMOCYTES. GRAVITY CHANGES ARE MAJOR STRESSORS ENCOUNTERED DURING SPACEFLIGHT THAT AFFECT THE IMMUNE SYSTEM. WE PREVIOUSLY EVIDENCED THAT HYPERGRAVITY EXPOSURE DURING GESTATION AFFECTS THE TCRBETA REPERTOIRE OF NEWBORN PUPS. TO IDENTIFY THE MECHANISMS UNDERLYING THIS OBSERVATION, WE STUDIED POST-TRANSLATIONAL HISTONE MODIFICATIONS. WE FIRST SHOWED THAT AMONG THE FOUR STUDIED POST-TRANSLATIONAL HISTONE H3 MODIFICATIONS, ONLY LYSINE 27 TRIMETHYLATION (H3K27ME3) IS DOWNREGULATED IN THE THYMUS OF MICE EXPOSED TO 2X G FOR 21 DAYS. WE THEN ASKED WHETHER THE TCRBETA LOCUS CHROMATIN STRUCTURE IS ALTERED BY HYPERGRAVITY EXPOSURE. CHIP STUDIES PERFORMED ON FOUR VBETA SEGMENTS OF THE MURINE DOUBLE-NEGATIVE SCIET27 THYMIC CELL LINE, WHICH CORRESPONDS TO THE LAST MATURATION STAGE BEFORE V(D)J RECOMBINATION, REVEALED INCREASES IN H3K27ME3 AFTER 2X G EXPOSURE. FINALLY, WE EVALUATED THE IMPLICATION FOR THE EZH2 METHYLTRANSFERASE IN THE REGULATION OF THE H3K27ME3 LEVEL AT THESE VBETA SEGMENTS BY TREATING SCIET27 CELLS WITH THE GSK126-SPECIFIC INHIBITOR. THESE EXPERIMENTS SHOWED THAT THE DOWNREGULATION OF H3K27ME3 CONTRIBUTES TO THE REGULATION OF THE VBETA GERMLINE TRANSCRIPT EXPRESSION THAT PRECEDES V(D)J RECOMBINATION. THESE DATA SHOW THAT MODIFICATIONS OF H3K27ME3 AT THE TCRBETA LOCUS LIKELY CONTRIBUTE TO AN EXPLANATION OF WHY THE TCR REPERTOIRE IS AFFECTED BY GRAVITY CHANGES AND IMPLY, FOR THE FIRST TIME, EZH2 IN THE REGULATION OF THE TCRBETA LOCUS CHROMATIN STRUCTURE. 2022 20 4742 32 NOVEL HISTONE MODIFICATIONS IN MICROGLIA DERIVED FROM A MOUSE MODEL OF CHRONIC PAIN. AS THE RESIDENT IMMUNE CELLS IN THE CENTRAL NERVOUS SYSTEM, MICROGLIA PLAY AN IMPORTANT ROLE IN THE MAINTENANCE OF ITS HOMEOSTASIS. DYSREGULATION OF MICROGLIA HAS BEEN ASSOCIATED WITH THE DEVELOPMENT AND MAINTENANCE OF CHRONIC PAIN. HOWEVER, THE RELEVANT MOLECULAR PATHWAYS REMAIN POORLY DEFINED. IN THIS STUDY, WE USED A MASS SPECTROMETRY-BASED PROTEOMIC APPROACH TO SCREEN POTENTIAL CHANGES OF HISTONE PROTEIN MODIFICATIONS IN MICROGLIA ISOLATED FROM THE BRAIN OF CONTROL AND CISPLATIN-INDUCED NEUROPATHIC PAIN ADULT C57BL/6J MALE MICE. WE IDENTIFIED SEVERAL NOVEL MICROGLIAL HISTONE MODIFICATIONS ASSOCIATED WITH PAIN, INCLUDING STATISTICALLY SIGNIFICANTLY DECREASED HISTONE H3.1 LYSINE 27 MONO-METHYLATION (H3.1K27ME1, 54.8% OF CONTROL) AND H3 LYSINE 56 TRI-METHYLATION (7.5% OF CONTROL), AS WELL AS A TREND SUGGESTING INCREASED H3 TYROSINE 41 NITRATION. WE FURTHER INVESTIGATED THE FUNCTIONAL ROLE OF H3.1K27ME1 AND FOUND THAT TREATMENT OF CULTURED MICROGLIAL CELLS FOR 4 CONSECUTIVE DAYS WITH 1-10 MUM OF NCDM-64, A POTENT AND SELECTIVE INHIBITOR OF LYSINE DEMETHYLASE 7A, AN ENZYME RESPONSIBLE FOR THE DEMETHYLATION OF H3K27ME1, DOSE-DEPENDENTLY ELEVATED ITS LEVELS WITH A GREATER THAN A TWO-FOLD INCREASE OBSERVED AT 10 MUM COMPARED TO VEHICLE-TREATED CONTROL CELLS. MOREOVER, PRETREATMENT OF MICE WITH NCDM-64 (10 OR 25 MG/KG/DAY, I.P.) PRIOR TO CISPLATIN TREATMENT PREVENTED THE DEVELOPMENT OF NEUROPATHIC PAIN IN MICE. THE IDENTIFICATION OF SPECIFIC CHROMATIN MARKS IN MICROGLIA ASSOCIATED WITH CHRONIC PAIN MAY YIELD CRITICAL INSIGHT INTO THE CONTRIBUTION OF MICROGLIA TO THE DEVELOPMENT AND MAINTENANCE OF PAIN, AND OPENS NEW AVENUES FOR THE DEVELOPMENT OF NOVEL NONOPIOID THERAPEUTICS FOR THE EFFECTIVE MANAGEMENT OF CHRONIC PAIN. 2022