1 3971 153 LONG-LASTING NEUROTOXIC EFFECTS OF EXPOSURE TO METHYLMERCURY DURING DEVELOPMENT. AMONGST ENVIRONMENTAL CHEMICAL CONTAMINANTS, METHYLMERCURY (MEHG) REMAINS A MAJOR CONCERN BECAUSE OF ITS DETRIMENTAL EFFECTS ON DEVELOPING ORGANISMS, WHICH APPEAR TO BE PARTICULARLY SUSCEPTIBLE TO ITS TOXICITY. HERE, WE INVESTIGATED THE EFFECTS OF LOW MEHG LEVELS ON THE DEVELOPMENT OF THE NERVOUS SYSTEM USING BOTH IN VITRO AND IN VIVO EXPERIMENTAL MODELS. IN NEURAL STEM CELLS (NSCS), MEHG DECREASED PROLIFERATION AND NEURONAL DIFFERENTIATION AND INDUCED CELLULAR SENESCENCE ASSOCIATED WITH IMPAIRMENT IN MITOCHONDRIAL FUNCTION AND A CONCOMITANT DECREASE IN GLOBAL DNA METHYLATION. INTERESTINGLY, THE EFFECTS WERE HERITABLE AND COULD BE OBSERVED IN DAUGHTER NSCS NEVER DIRECTLY EXPOSED TO MEHG. BY CHRONICALLY EXPOSING PREGNANT/LACTATING MICE TO MEHG, WE FOUND PERSISTENT BEHAVIOURAL CHANGES IN THE MALE OFFSPRING, WHICH EXHIBITED DEPRESSION-LIKE BEHAVIOUR THAT COULD BE REVERSED BY CHRONIC TREATMENT WITH THE ANTIDEPRESSANT FLUOXETINE. THE BEHAVIOURAL ALTERATIONS WERE ASSOCIATED WITH A DECREASED NUMBER OF PROLIFERATING CELLS AND LOWER EXPRESSION OF BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) MRNA IN THE HIPPOCAMPAL DENTATE GYRUS. MEHG EXPOSURE ALSO INDUCED LONG-LASTING DNA HYPERMETHYLATION, INCREASED HISTONE H3-K27 TRI-METHYLATION AND DECREASED H3 ACETYLATION AT THE BDNF PROMOTER IV, INDICATING THAT EPIGENETIC MECHANISMS PLAY A CRITICAL ROLE IN MEDIATING THE LONG-LASTING EFFECTS OF PERINATAL EXPOSURE TO MEHG. FLUOXETINE TREATMENT RESTORED THE BDNF MRNA EXPRESSION LEVELS, AS WELL AS THE NUMBER OF PROLIFERATING CELLS IN THE GRANULE CELL LAYER OF THE DENTATE GYRUS, WHICH FURTHER SUPPORTS THE HYPOTHESIS THAT LINKS DEPRESSION TO IMPAIRED NEUROGENESIS. ALTOGETHER, OUR FINDINGS HAVE SHOWN THAT LOW CONCENTRATIONS OF MEHG INDUCE LONG-LASTING EFFECTS IN NSCS THAT CAN POTENTIALLY PREDISPOSE INDIVIDUALS TO DEPRESSION, WHICH WE HAVE REPORTED EARLIER TO OCCUR IN EXPERIMENTAL ANIMALS EXPOSED TO MEHG DURING PRENATAL AND EARLY POSTNATAL DEVELOPMENT. 2013 2 3715 73 INHERITED EFFECTS OF LOW-DOSE EXPOSURE TO METHYLMERCURY IN NEURAL STEM CELLS. METHYLMERCURY (MEHG) IS AN ENVIRONMENTAL CONTAMINANT WITH RECOGNIZED NEUROTOXIC EFFECTS, PARTICULARLY TO THE DEVELOPING NERVOUS SYSTEM. IN THE PRESENT STUDY, WE SHOW THAT NANOMOLAR CONCENTRATIONS OF MEHG CAN INDUCE LONG-LASTING EFFECTS IN NEURAL STEM CELLS (NSCS). WE INVESTIGATED SHORT-TERM DIRECT AND LONG-TERM INHERITED EFFECTS OF EXPOSURE TO MEHG (2.5 OR 5.0 NM) USING PRIMARY CULTURES OF RAT EMBRYONIC CORTICAL NSCS. WE FOUND THAT MEHG HAD NO ADVERSE EFFECT ON CELL VIABILITY BUT REDUCED NSC PROLIFERATION AND ALTERED THE EXPRESSION OF CELL CYCLE REGULATORS (P16 AND P21) AND SENESCENCE-ASSOCIATED MARKERS. IN ADDITION, WE DEMONSTRATED A DECREASE IN GLOBAL DNA METHYLATION IN THE EXPOSED CELLS, INDICATING THAT EPIGENETIC CHANGES MAY BE INVOLVED IN THE MECHANISMS UNDERLYING THE MEHG-INDUCED EFFECTS. THESE CHANGES WERE OBSERVED IN CELLS DIRECTLY EXPOSED TO MEHG (PARENT CELLS) AND IN THEIR DAUGHTER CELLS CULTURED UNDER MEHG-FREE CONDITIONS. IN AGREEMENT WITH OUR IN VITRO DATA, A TREND WAS FOUND FOR DECREASED CELL PROLIFERATION IN THE SUBGRANULAR ZONE IN THE HIPPOCAMPI OF ADULT MICE EXPOSED TO LOW DOSES OF MEHG DURING THE PERINATAL PERIOD. INTERESTINGLY, THIS IMPAIRED PROLIFERATION HAD A MEASURABLE IMPACT ON THE TOTAL NUMBER OF NEURONS IN THE HIPPOCAMPAL DENTATE GYRUS. IMPORTANTLY, THIS EFFECT COULD BE REVERSED BY CHRONIC ANTIDEPRESSANT TREATMENT. OUR STUDY PROVIDES NOVEL EVIDENCE FOR PROGRAMMING EFFECTS INDUCED BY MEHG IN NSCS AND SUPPORTS THE IDEA THAT DEVELOPMENTAL EXPOSURE TO LOW LEVELS OF MEHG MAY RESULT IN LONG-TERM CONSEQUENCES PREDISPOSING TO NEURODEVELOPMENTAL DISORDERS AND/OR NEURODEGENERATION. 2012 3 89 44 A PILOT INVESTIGATION OF DIFFERENTIAL HYDROXYMETHYLATION LEVELS IN PATIENT-DERIVED NEURAL STEM CELLS IMPLICATES ALTERED CORTICAL DEVELOPMENT IN BIPOLAR DISORDER. INTRODUCTION: BIPOLAR DISORDER (BD) IS A CHRONIC MENTAL ILLNESS CHARACTERIZED BY RECURRENT EPISODES OF MANIA AND DEPRESSION AND ASSOCIATED WITH SOCIAL AND COGNITIVE DISTURBANCES. ENVIRONMENTAL FACTORS, SUCH AS MATERNAL SMOKING AND CHILDHOOD TRAUMA, ARE BELIEVED TO MODULATE RISK GENOTYPES AND CONTRIBUTE TO THE PATHOGENESIS OF BD, SUGGESTING A KEY ROLE IN EPIGENETIC REGULATION DURING NEURODEVELOPMENT. 5-HYDROXYMETHYLCYTOSINE (5HMC) IS AN EPIGENETIC VARIANT OF PARTICULAR INTEREST, AS IT IS HIGHLY EXPRESSED IN THE BRAIN AND IS IMPLICATED IN NEURODEVELOPMENT, AND PSYCHIATRIC AND NEUROLOGICAL DISORDERS. METHODS: INDUCED PLURIPOTENT STEM CELLS (IPSCS) WERE GENERATED FROM THE WHITE BLOOD CELLS OF TWO ADOLESCENT PATIENTS WITH BIPOLAR DISORDER AND THEIR SAME-SEX AGE-MATCHED UNAFFECTED SIBLINGS (N = 4). FURTHER, IPSCS WERE DIFFERENTIATED INTO NEURONAL STEM CELLS (NSCS) AND CHARACTERIZED FOR PURITY USING IMMUNO-FLUORESCENCE. WE USED REDUCED REPRESENTATION HYDROXYMETHYLATION PROFILING (RRHP) TO PERFORM GENOME-WIDE 5HMC PROFILING OF IPSCS AND NSCS, TO MODEL 5HMC CHANGES DURING NEURONAL DIFFERENTIATION AND ASSESS THEIR IMPACT ON BD RISK. FUNCTIONAL ANNOTATION AND ENRICHMENT TESTING OF GENES HARBORING DIFFERENTIATED 5HMC LOCI WERE PERFORMED WITH THE ONLINE TOOL DAVID. RESULTS: APPROXIMATELY 2 MILLION SITES WERE MAPPED AND QUANTIFIED, WITH THE MAJORITY (68.8%) LOCATED IN GENIC REGIONS, WITH ELEVATED 5HMC LEVELS PER SITE OBSERVED FOR 3' UTRS, EXONS, AND 2-KB SHORELINES OF CPG ISLANDS. PAIRED T-TESTS OF NORMALIZED 5HMC COUNTS BETWEEN IPSC AND NSC CELL LINES REVEALED GLOBAL HYPO-HYDROXYMETHYLATION IN NSCS AND ENRICHMENT OF DIFFERENTIALLY HYDROXYMETHYLATED SITES WITHIN GENES ASSOCIATED WITH PLASMA MEMBRANE (FDR = 9.1 X 10(-12)) AND AXON GUIDANCE (FDR = 2.1 X 10(-6)), AMONG OTHER NEURONAL PROCESSES. THE MOST SIGNIFICANT DIFFERENCE WAS OBSERVED FOR A TRANSCRIPTION FACTOR BINDING SITE FOR THE KCNK9 GENE (P = 8.8 X 10(-6)), ENCODING A POTASSIUM CHANNEL PROTEIN INVOLVED IN NEURONAL ACTIVITY AND MIGRATION. PROTEIN-PROTEIN-INTERACTION (PPI) NETWORKING SHOWED SIGNIFICANT CONNECTIVITY (P = 3.2 X 10(-10)) BETWEEN PROTEINS ENCODED BY GENES HARBORING HIGHLY DIFFERENTIATED 5HMC SITES, WITH GENES INVOLVED IN AXON GUIDANCE AND ION TRANSMEMBRANE TRANSPORT FORMING DISTINCT SUB-CLUSTERS. COMPARISON OF NSCS OF BD CASES AND UNAFFECTED SIBLINGS REVEALED ADDITIONAL PATTERNS OF DIFFERENTIATION IN HYDROXYMETHYLATION LEVELS, INCLUDING SITES IN GENES WITH FUNCTIONS RELATED TO SYNAPSE FORMATION AND REGULATION, SUCH AS CUX2 (P = 2.4 X 10(-5)) AND DOK-7 (P = 3.6 X 10(-3)), AS WELL AS AN ENRICHMENT OF GENES INVOLVED IN THE EXTRACELLULAR MATRIX (FDR = 1.0 X 10(-8)). DISCUSSION: TOGETHER, THESE PRELIMINARY RESULTS LEND EVIDENCE TOWARD A POTENTIAL ROLE FOR 5HMC IN BOTH EARLY NEURONAL DIFFERENTIATION AND BD RISK, WITH VALIDATION AND MORE COMPREHENSIVE CHARACTERIZATION TO BE ACHIEVED THROUGH FOLLOW-UP STUDY. 2023 4 1850 43 ELECTROACUPUNCTURE AMELIORATES DEPRESSION-LIKE BEHAVIORS COMORBID TO CHRONIC NEUROPATHIC PAIN VIA TET1-MEDIATED RESTORATION OF ADULT NEUROGENESIS. ALTHOUGH ELECTROACUPUNCTURE (EA) STIMULATION IS A WIDELY USED THERAPY FOR CHRONIC PAIN AND COMORBID PSYCHIATRIC DISORDERS, ITS LONG-TERM EFFECTS ON CHRONIC NEUROPATHIC PAIN-INDUCED DEPRESSION AND THE UNDERLYING MECHANISMS REMAIN ELUSIVE. IN THE PRESENT STUDY, WE FOUND THAT EA STIMULATION WAS ABLE TO RESTORE ADULT NEUROGENESIS IN THE VENTRAL DENTATE GYRUS (DG), BY BOTH INCREASING NEURONAL DIFFERENTIATION AND RESTORING THE NORMAL MORPHOLOGY OF NEWBORN DENDRITES, IN MICE WITH SPARED NERVE INJURY SURGERY. BY ABLATING THE NESTIN+ NEURAL STEM CELLS (NSCS) VIA DIPHTHERIA TOXIN FRAGMENT A EXPRESSION, WE FURTHER PROVED THAT NEUROGENESIS IN THE VENTRAL DG WAS CRUCIAL TO THE LONG-TERM, BUT NOT THE IMMEDIATE ANTIDEPRESSANT EFFECT OF EA, NOR WAS IT ASSOCIATED WITH NOCICEPTION. FURTHERMORE, WE FOUND THAT THE RESTORATION OF NEUROGENESIS WAS DEPENDENT ON TET1-MEDIATED EPIGENETIC MODIFICATION UPON EA TREATMENT. TET1 COULD BIND TO THE PROMOTER OF THE PROX1 GENE, THUS CATALYZING ITS DEMETHYLATION AND FACILITATING ITS EXPRESSION, WHICH FINALLY CONTRIBUTED TO THE RESTORATION OF NEUROGENESIS AND AMELIORATION OF DEPRESSION-LIKE BEHAVIORS INDUCED BY CHRONIC NEUROPATHIC PAIN. THUS, WE CONCLUDE THAT EA STIMULATION RESTORES INHIBITED TET1 EXPRESSION IN HIPPOCAMPAL NSCS OF MICE WITH CHRONIC NEUROPATHIC PAIN, AND INCREASED TET1 EXPRESSION AMELIORATES HYPERMETHYLATION OF PROX1 AND RESTORES NORMAL ADULT NEUROGENESIS IN THE VENTRAL DG, WHICH CONTRIBUTES TO THE LONG-TERM ANTIDEPRESSANT EFFECT OF EA. 2023 5 2927 43 GENERATION OF HUMAN CORTICAL NEURONS FROM A NEW IMMORTAL FETAL NEURAL STEM CELL LINE. ISOLATION AND EXPANSION OF NEURAL STEM CELLS (NSCS) OF HUMAN ORIGIN ARE CRUCIAL FOR SUCCESSFUL DEVELOPMENT OF CELL THERAPY APPROACHES IN NEURODEGENERATIVE DISEASES. DIFFERENT EPIGENETIC AND GENETIC IMMORTALIZATION STRATEGIES HAVE BEEN ESTABLISHED FOR LONG-TERM MAINTENANCE AND EXPANSION OF THESE CELLS IN VITRO. HERE WE REPORT THE GENERATION OF A NEW, CLONAL NSC (HC-NSC) LINE, DERIVED FROM HUMAN FETAL CORTICAL TISSUE, BASED ON V-MYC IMMORTALIZATION. USING IMMUNOCYTOCHEMISTRY, WE SHOW THAT THESE CELLS RETAIN THE CHARACTERISTICS OF NSCS AFTER MORE THAN 50 PASSAGES. UNDER PROLIFERATION CONDITIONS, WHEN SUPPLEMENTED WITH EPIDERMAL AND BASIC FIBROBLAST GROWTH FACTORS, THE HC-NSCS EXPRESSED NEURAL STEM/PROGENITOR CELL MARKERS LIKE NESTIN, VIMENTIN AND SOX2. WHEN GROWTH FACTORS WERE WITHDRAWN, PROLIFERATION AND EXPRESSION OF V-MYC AND TELOMERASE WERE DRAMATICALLY REDUCED, AND THE HC-NSCS DIFFERENTIATED INTO GLIA AND NEURONS (MOSTLY GLUTAMATERGIC AND GABAERGIC, AS WELL AS TYROSINE HYDROXYLASE-POSITIVE, PRESUMABLY DOPAMINERGIC NEURONS). RT-PCR ANALYSIS SHOWED THAT THE HC-NSCS RETAINED EXPRESSION OF PAX6, EMX2 AND NEUROGENIN2, WHICH ARE GENES ASSOCIATED WITH REGIONALIZATION AND CELL COMMITMENT IN CORTICAL PRECURSORS DURING BRAIN DEVELOPMENT. OUR DATA INDICATE THAT THIS HC-NSC LINE COULD BE USEFUL FOR EXPLORING THE POTENTIAL OF HUMAN NSCS TO REPLACE DEAD OR DAMAGED CORTICAL CELLS IN ANIMAL MODELS OF ACUTE AND CHRONIC NEURODEGENERATIVE DISEASES. TAKING ADVANTAGE OF ITS CLONALITY AND HOMOGENEITY, THIS CELL LINE WILL ALSO BE A VALUABLE EXPERIMENTAL TOOL TO STUDY THE REGULATORY ROLE OF INTRINSIC AND EXTRINSIC FACTORS IN HUMAN NSC BIOLOGY. 2007 6 2072 33 EPIGENETIC CONVERSION OF HUMAN ADULT BONE MESODERMAL STROMAL CELLS INTO NEUROECTODERMAL CELL TYPES FOR REPLACEMENT THERAPY OF NEURODEGENERATIVE DISORDERS. TISSUE-SPECIFIC STEM CELLS, SUCH AS BONE MARROW-DERIVED MESODERMAL STROMAL CELLS (MSCS), ARE THOUGHT TO BE LINEAGE RESTRICTED AND, THEREFORE, COULD ONLY BE DIFFERENTIATED INTO CELL TYPES OF THE TISSUE OF ORIGIN. SEVERAL RECENT STUDIES, HOWEVER, SUGGEST THAT THESE TYPES OF STEM CELLS MIGHT BE ABLE TO BREAK BARRIERS OF GERM LAYER COMMITMENT AND DIFFERENTIATE IN VITRO AND/OR IN VIVO INTO CELLS OF DIFFERENT TISSUES, SUCH AS NEUROECTODERMAL CELL TYPES. RECENTLY, PROTOCOLS FOR HIGH-YIELD GENERATION OF UNDIFFERENTIATED NEURAL STEM CELL (NSC)-LIKE CELLS FROM MSCS OF PRIMATE AND HUMAN ORIGIN WERE REPORTED. UNDIFFERENTIATED NSCS ARE COMMONLY USED AND ARE MORE SUITABLE FOR NEUROTRANSPLANTATION COMPARED WITH FULLY DIFFERENTIATED NEURAL CELLS, AS DIFFERENTIATED NEURAL CELLS ARE WELL KNOWN TO POORLY SURVIVE DETACHMENT AND SUBSEQUENT TRANSPLANTATION PROCEDURES. THESE HUMAN MSC-DERIVED NSC-LIKE CELLS (MSC-NSCS) GROW IN NEUROSPHERE-LIKE STRUCTURES AND EXPRESS HIGH LEVELS OF EARLY NEUROECTODERMAL MARKERS, BUT LOSE CHARACTERISTICS OF MSCS. IN THE PRESENCE OF SELECTED GROWTH FACTORS, HUMAN MSC-NSCS CAN BE DIFFERENTIATED INTO THE THREE MAIN NEURAL PHENOTYPES: ASTROGLIA, OLIGODENDROGLIA AND NEURONS. COMPARED WITH DIRECT DIFFERENTIATION OF HUMAN MSCS INTO MATURE NEURAL CELLS, THE CONVERSION STEP SEEMS TO BE ESSENTIAL TO GENERATE MATURE FUNCTIONAL NEUROECTODERMAL CELLS. THIS REVIEW DESCRIBES THE TECHNIQUES FOR THE CONVERSION OF HUMAN MSCS INTO NSCS AND SUMMARISES THE DATA ON EPIGENETIC CONVERSION OF HUMAN MSCS INTO IMMATURE NEUROECTODERMAL CELLS. THESE CELLS PROVIDE A POWERFUL TOOL FOR INVESTIGATING THE MOLECULAR MECHANISMS OF NEURAL DIFFERENTIATION, AND MIGHT SERVE AS AN AUTOLOGOUS CELL SOURCE TO TREAT ACUTE AND CHRONIC NEURODEGENERATIVE DISEASES. 2006 7 892 47 CHRONIC ETHANOL EXPOSURE ALTERS DNA METHYLATION IN NEURAL STEM CELLS: ROLE OF MOUSE STRAIN AND SEX. PRENATAL ALCOHOL EXPOSURE (PAE) IS CONSIDERED AS A RISK FACTOR FOR THE DEVELOPMENT OF FETAL ALCOHOL SPECTRUM DISORDERS (FASD). EVIDENCE INDICATES THAT PAE AFFECTS EPIGENETIC MECHANISMS (SUCH AS DNA METHYLATION) AND ALTERS THE NORMAL DIFFERENTIATION AND DEVELOPMENT OF NEURAL STEM CELLS (NSC) IN THE FETAL BRAIN. HOWEVER, PAE EFFECTS DEPEND ON SEVERAL FACTORS SUCH AS SEX AND STRAIN OF THE STUDIED SUBJECTS. HERE, WE INVESTIGATED WHETHER MURINE SEX AND STRAIN CONTRIBUTE TO THE EFFECTS OF CHRONIC ETHANOL EXPOSURE ON DNA METHYLATION MACHINERY OF DIFFERENTIATING NSC. FURTHER, THE EFFECTS OF PAE ON GLIAL LINEAGE (INCLUDING BOTH ASTROCYTES AND OLIGODENDROCYTES) IN A SEX- AND STRAIN-DEPENDENT MANNER HAVE NOT BEEN STUDIED YET. TO EXAMINE THE EFFECTS OF CHRONIC ETHANOL EXPOSURE ON GLIOGENESIS, WE EXPOSED DIFFERENTIATING NSC TO GLIO-INDUCTIVE CULTURE CONDITIONS. APPLYING A STANDARD IN VITRO MODEL SYSTEM, WE TREATED MALE AND FEMALE DIFFERENTIATING NSC (OBTAINED FROM THE FOREBRAIN OF CD1 AND C57BL/6 EMBRYOS AT EMBRYONIC DAY 14.5) WITH CHRONIC ETHANOL EXPOSURE (70 MM) FOR 8 DAYS. WE SHOW THAT ETHANOL INDUCES GLOBAL DNA HYPOMETHYLATION, WHILE ALTERING THE EXPRESSION OF DNA METHYLATION-RELATED GENES IN A SEX- AND STRAIN-SPECIFIC MANNER. THE OBSERVED CHANGE IN CELLULAR DNA METHYLATION LEVELS WAS ASSOCIATED WITH ALTERED EXPRESSION OF GLIAL MARKERS CNPASE, GFAP, AND OLIG2 IN CD1 (BUT NOT C57BL/6) CELLS. WE CONCLUDE THAT THE IMPACT OF ETHANOL EFFECT ON DNA METHYLATION IS DEPENDENT ON CELLULAR SEX AND STRAIN. ALSO, ETHANOL IMPACT ON NEURAL STEM CELL FATE COMMITMENT WAS ONLY DETECTED IN CELLS ISOLATED FROM CD1 MOUSE STRAIN, BUT NOT IN C57BL/6 CELLS. THE RESULTS OF THE CURRENT STUDY PROVIDE EVIDENCE THAT SEX AND STRAIN OF RODENTS (C57BL/6 AND CD1) DURING GESTATION ARE IMPORTANT FACTORS, WHICH AFFECT ALCOHOL EFFECTS ON NSC DIFFERENTIATION AND DNA METHYLATION. RESULTS OF THIS STUDY MAY ALSO HELP IN INTERPRETING DATA ON THE DEVELOPMENTAL TOXICITY OF MANY COMPOUNDS DURING THE GESTATIONAL PERIOD. 2020 8 2827 36 FLUOXETINE INCREASES HIPPOCAMPAL NEUROGENESIS AND INDUCES EPIGENETIC FACTORS BUT DOES NOT IMPROVE FUNCTIONAL RECOVERY AFTER TRAUMATIC BRAIN INJURY. THE SELECTIVE SEROTONIN REUPTAKE INHIBITOR FLUOXETINE INDUCES HIPPOCAMPAL NEUROGENESIS, STIMULATES MATURATION AND SYNAPTIC PLASTICITY OF ADULT HIPPOCAMPAL NEURONS, AND REDUCES MOTOR/SENSORY AND MEMORY IMPAIRMENTS IN SEVERAL CNS DISORDERS. IN THE SETTING OF TRAUMATIC BRAIN INJURY (TBI), ITS EFFECTS ON NEUROPLASTICITY AND FUNCTION HAVE YET TO BE THOROUGHLY INVESTIGATED. HERE WE EXAMINED THE EFFICACY OF FLUOXETINE AFTER A MODERATE TO SEVERE TBI, PRODUCED BY A CONTROLLED CORTICAL IMPACT. THREE DAYS AFTER TBI OR SHAM SURGERY, MICE WERE TREATED WITH FLUOXETINE (10 MG/KG/D) OR VEHICLE FOR 4 WEEKS. TO EVALUATE THE EFFECTS OF FLUOXETINE ON NEUROPLASTICITY, HIPPOCAMPAL NEUROGENESIS AND EPIGENETIC MODIFICATION WERE STUDIED. STEREOLOGIC ANALYSIS OF THE DENTATE GYRUS REVEALED A SIGNIFICANT INCREASE IN DOUBLECORTIN-POSITIVE CELLS IN BRAIN-INJURED ANIMALS TREATED WITH FLUOXETINE RELATIVE TO CONTROLS, A FINDING CONSISTENT WITH ENHANCED HIPPOCAMPAL NEUROGENESIS. EPIGENETIC MODIFICATIONS, INCLUDING AN INCREASE IN HISTONE 3 ACETYLATION AND INDUCTION OF METHYL-CPG-BINDING PROTEIN, A TRANSCRIPTION FACTOR INVOLVED IN DNA METHYLATION, WERE LIKEWISE SEEN BY IMMUNOHISTOCHEMISTRY AND QUANTITATIVE WESTERN IMMUNOBLOTS, RESPECTIVELY, IN BRAIN-INJURED ANIMALS TREATED WITH FLUOXETINE. TO DETERMINE IF FLUOXETINE IMPROVES NEUROLOGICAL OUTCOMES AFTER TBI, GAIT FUNCTION AND SPATIAL LEARNING AND MEMORY WERE ASSESSED BY THE CATWALK-ASSISTED GAIT TEST AND BARNES MAZE TEST, RESPECTIVELY. NO DIFFERENCES IN THESE PARAMETERS WERE SEEN BETWEEN FLUOXETINE- AND VEHICLE-TREATED ANIMALS. THUS WHILE FLUOXETINE ENHANCED NEUROPLASTICITY IN THE HIPPOCAMPUS AFTER TBI, ITS CHRONIC ADMINISTRATION DID NOT RESTORE LOCOMOTOR FUNCTION OR AMELIORATE MEMORY DEFICITS. 2011 9 4180 47 MERCURY EXPOSURE INDUCES CYTOSKELETON DISRUPTION AND LOSS OF RENAL FUNCTION THROUGH EPIGENETIC MODULATION OF MMP9 EXPRESSION. MERCURY IS ONE OF THE MAJOR HEAVY METAL POLLUTANTS OCCURRING IN ELEMENTAL, INORGANIC AND ORGANIC FORMS. DUE TO BAN ON MOST INORGANIC MERCURY CONTAINING PRODUCTS, HUMAN EXPOSURE TO MERCURY GENERALLY OCCURS AS METHYLMERCURY (MEHG) BY CONSUMPTION OF CONTAMINATED FISH AND OTHER SEA FOOD. ANIMAL AND EPIDEMIOLOGICAL STUDIES INDICATE THAT MEHG AFFECTS NEURAL AND RENAL FUNCTION. OUR STUDY IS FOCUSED ON NEPHROTOXIC POTENTIAL OF MEHG. IN THIS STUDY, WE HAVE SHOWN FOR THE FIRST TIME HOW MEHG COULD EPIGENETICALLY MODULATE MATRIX METALLOPROTEINASE 9(MMP9) TO PROMOTE NEPHROTOXICITY USING AN ANIMAL MODEL OF SUB CHRONIC MEHG EXPOSURE. MEHG CAUSED RENAL TOXICITY AS WAS SEEN BY INCREASED LEVELS OF SERUM CREATININE AND EXPRESSION OF EARLY NEPHROTOXICITY MARKERS (KIM-1, CLUSTERIN, IP-10, AND TIMP). MEHG EXPOSURE ALSO CORRELATED STRONGLY WITH INDUCTION OF MMP9 MRNA AND PROTEIN IN A DOSE DEPENDENT MANNER. FURTHER, WHILE INDUCTION OF MMP9 PROMOTED CYTOSKELETON DISRUPTION AND LOSS OF CELL-CELL ADHESION (LOSS OF F-ACTIN, VIMENTIN AND FIBRONECTIN), INHIBITION OF MMP9 WAS FOUND TO REDUCE THESE DISRUPTIONS. MECHANISTIC STUDIES BY CHIP ANALYSIS SHOWED THAT MEHG MODULATED MMP9 BY PROMOTING DEMETHYLATION OF ITS REGULATORY REGION TO INCREASE ITS EXPRESSION. BISULFITE SEQUENCING IDENTIFIED CRITICAL CPGS IN THE FIRST EXON OF MMP9 WHICH WERE DEMETHYLATED FOLLOWING MEHG EXPOSURE. CHIP STUDIES ALSO SHOWED LOSS OF METHYL BINDING PROTEIN, MECP2 AND TRANSCRIPTION FACTOR PEA3 AT THE DEMETHYLATED SITE CONFIRMING DECREASED CPG METHYLATION. OUR STUDIES THUS SHOW HOW MEHG COULD EPIGENETICALLY MODULATE MMP9 TO PROMOTE CYTOSKELETON DISRUPTION LEADING TO LOSS OF RENAL FUNCTION. 2017 10 3969 65 LONG-LASTING DEPRESSION-LIKE BEHAVIOR AND EPIGENETIC CHANGES OF BDNF GENE EXPRESSION INDUCED BY PERINATAL EXPOSURE TO METHYLMERCURY. SUBSTANTIAL EVIDENCE INDICATES THAT PREDISPOSITION TO DISEASES CAN BE ACQUIRED DURING EARLY STAGES OF DEVELOPMENT AND INTERACTIONS BETWEEN ENVIRONMENTAL AND GENETIC FACTORS MAY BE IMPLICATED IN THE ONSET OF MANY PATHOLOGICAL CONDITIONS. DATA COLLECTED OVER SEVERAL DECADES HAVE SHOWN THAT CHEMICALS ARE AMONG THE RELEVANT FACTORS THAT CAN ENDANGER CNS. WE PREVIOUSLY SHOWED THAT PERINATAL EXPOSURE TO METHYLMERCURY (MEHG) CAUSES PERSISTENT CHANGES IN LEARNING AND MOTIVATIONAL BEHAVIOR IN MICE. IN THIS STUDY, WE REPORT THAT THE DEPRESSION-LIKE BEHAVIOR IN MEHG-EXPOSED MALE MICE IS REVERSED BY CHRONIC TREATMENT WITH THE ANTIDEPRESSANT FLUOXETINE. BEHAVIORAL ALTERATIONS ARE ASSOCIATED WITH A DECREASE IN BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) MRNA IN THE HIPPOCAMPAL DENTATE GYRUS AND FLUOXETINE TREATMENT RESTORES BDNF MRNA EXPRESSION. WE ALSO SHOW THAT MEHG-EXPOSURE INDUCES LONG-LASTING REPRESSIVE STATE OF THE CHROMATIN STRUCTURE AT THE BDNF PROMOTER REGION, IN PARTICULAR DNA HYPERMETHYLATION, AN INCREASE IN HISTONE H3-K27 TRI-METHYLATION AND A DECREASE IN H3 ACETYLATION AT THE PROMOTER IV. WHILE FLUOXETINE TREATMENT DOES NOT ALTER HYPERMETHYLATION OF H3-K27, IT SIGNIFICANTLY UP-REGULATES H3 ACETYLATION AT THE BDNF PROMOTER IV IN MEHG-EXPOSED MICE. OUR STUDY SHOWS THAT DEVELOPMENTAL EXPOSURE TO LOW LEVELS OF MEHG PREDISPOSES MICE TO DEPRESSION AND INDUCES EPIGENETIC SUPPRESSION OF BDNF GENE EXPRESSION IN THE HIPPOCAMPUS. 2008 11 1761 49 EARLY STRESS EVOKES AGE-DEPENDENT BIPHASIC CHANGES IN HIPPOCAMPAL NEUROGENESIS, BDNF EXPRESSION, AND COGNITION. BACKGROUND: ADULT-ONSET STRESSORS EXERT OPPOSING EFFECTS ON HIPPOCAMPAL NEUROGENESIS AND COGNITION, WITH ENHANCEMENT OBSERVED FOLLOWING MILD STRESS AND DYSFUNCTION FOLLOWING SEVERE CHRONIC STRESS. WHILE EARLY LIFE STRESS EVOKES PERSISTENT CHANGES IN ANXIETY, IT IS UNKNOWN WHETHER EARLY STRESS DIFFERENTIALLY REGULATES HIPPOCAMPAL NEUROGENESIS, TROPHIC FACTOR EXPRESSION, AND COGNITION ACROSS THE LIFE SPAN. METHODS: HIPPOCAMPAL-DEPENDENT COGNITIVE BEHAVIOR, NEUROGENESIS, AND EPIGENETIC REGULATION OF BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) EXPRESSION WAS EXAMINED AT DISTINCT TIME POINTS ACROSS THE LIFE SPAN IN RATS SUBJECTED TO THE EARLY STRESS OF MATERNAL SEPARATION (ES) AND CONTROL GROUPS. WE ALSO EXAMINED THE INFLUENCE OF CHRONIC ANTIDEPRESSANT TREATMENT ON THE NEUROGENIC, NEUROTROPHIC, AND COGNITIVE CHANGES IN MIDDLE-AGED ES ANIMALS. RESULTS: ANIMALS SUBJECTED TO EARLY STRESS OF MATERNAL SEPARATION EXAMINED DURING POSTNATAL LIFE AND YOUNG ADULTHOOD EXHIBITED ENHANCED HIPPOCAMPAL NEUROGENESIS, DECREASED REPRESSIVE HISTONE METHYLATION AT THE BDNF IV PROMOTER ALONG WITH ENHANCED BDNF LEVELS, AND IMPROVED PERFORMANCE ON THE STRESS-ASSOCIATED MORRIS WATER MAZE. STRIKINGLY, OPPOSING CHANGES IN HIPPOCAMPAL NEUROGENESIS AND EPIGENETIC REGULATION OF BDNF IV EXPRESSION, CONCOMITANT WITH IMPAIRMENTS ON HIPPOCAMPAL-DEPENDENT COGNITIVE TASKS, WERE OBSERVED IN MIDDLE-AGED ES ANIMALS. CHRONIC ANTIDEPRESSANT TREATMENT WITH AMITRIPTYLINE ATTENUATED THE MALADAPTIVE NEUROGENIC, EPIGENETIC, TRANSCRIPTIONAL, AND COGNITIVE EFFECTS IN MIDDLE-AGED ES ANIMALS. CONCLUSIONS: OUR STUDY PROVIDES NOVEL INSIGHTS INTO THE SHORT- AND LONG-TERM CONSEQUENCES OF ES, DEMONSTRATING BOTH BIPHASIC AND UNIQUE, AGE-DEPENDENT CHANGES AT THE MOLECULAR, EPIGENETIC, NEUROGENIC, AND BEHAVIORAL LEVELS. THESE RESULTS INDICATE THAT EARLY STRESS MAY TRANSIENTLY ENDOW ANIMALS WITH A POTENTIAL ADAPTIVE ADVANTAGE IN STRESSFUL ENVIRONMENTS BUT ACROSS A LIFE SPAN IS ASSOCIATED WITH LONG-TERM DELETERIOUS EFFECTS. 2013 12 579 46 BEHAVIORAL AND MOLECULAR NEUROEPIGENETIC ALTERATIONS IN PRENATALLY STRESSED MICE: RELEVANCE FOR THE STUDY OF CHROMATIN REMODELING PROPERTIES OF ANTIPSYCHOTIC DRUGS. WE HAVE RECENTLY REPORTED THAT MICE BORN FROM DAMS STRESSED DURING PREGNANCY (PRS MICE), IN ADULTHOOD, HAVE BEHAVIORAL DEFICITS REMINISCENT OF BEHAVIORS OBSERVED IN SCHIZOPHRENIA (SZ) AND BIPOLAR (BP) DISORDER PATIENTS. FURTHERMORE, WE HAVE SHOWN THAT THE FRONTAL CORTEX (FC) AND HIPPOCAMPUS OF ADULT PRS MICE, LIKE THAT OF POSTMORTEM CHRONIC SZ PATIENTS, ARE CHARACTERIZED BY INCREASES IN DNA-METHYLTRANSFERASE 1 (DNMT1), TEN-ELEVEN METHYLCYTOSINE DIOXYGENASE 1 (TET1) AND EXHIBIT AN ENRICHMENT OF 5-METHYLCYTOSINE (5MC) AND 5-HYDROXYMETHYLCYTOSINE (5HMC) AT NEOCORTICAL GABAERGIC AND GLUTAMATERGIC GENE PROMOTERS. HERE, WE SHOW THAT THE BEHAVIORAL DEFICITS AND THE INCREASED 5MC AND 5HMC AT GLUTAMIC ACID DECARBOXYLASE 67 (GAD1), REELIN (RELN) AND BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) PROMOTERS AND THE REDUCED EXPRESSION OF THE MESSENGER RNAS (MRNAS) AND PROTEINS CORRESPONDING TO THESE GENES IN FC OF ADULT PRS MICE IS REVERSED BY TREATMENT WITH CLOZAPINE (5 MG KG(-1) TWICE A DAY FOR 5 DAYS) BUT NOT BY HALOPERIDOL (1 MG KG(-1) TWICE A DAY FOR 5 DAYS). INTERESTINGLY, CLOZAPINE HAD NO EFFECT ON EITHER THE BEHAVIOR, PROMOTER METHYLATION OR THE EXPRESSION OF THESE MRNAS AND PROTEINS WHEN ADMINISTERED TO OFFSPRING OF NONSTRESSED PREGNANT MICE. CLOZAPINE, BUT NOT HALOPERIDOL, REDUCED THE ELEVATED LEVELS OF DNMT1 AND TET1, AS WELL AS THE ELEVATED LEVELS OF DNMT1 BINDING TO GAD1, RELN AND BDNF PROMOTERS IN PRS MICE SUGGESTING THAT CLOZAPINE, UNLIKE HALOPERIDOL, MAY LIMIT DNA METHYLATION BY INTERFERING WITH DNA METHYLATION DYNAMICS. WE CONCLUDE THAT THE PRS MOUSE MODEL MAY BE USEFUL PRECLINICALLY IN SCREENING FOR THE POTENTIAL EFFICACY OF ANTIPSYCHOTIC DRUGS ACTING ON ALTERED EPIGENETIC MECHANISMS. FURTHERMORE, PRS MICE MAY BE INVALUABLE FOR UNDERSTANDING THE ETIOPATHOGENESIS OF SZ AND BP DISORDER AND FOR PREDICTING TREATMENT RESPONSES AT EARLY STAGES OF THE ILLNESS ALLOWING FOR EARLY DETECTION AND REMEDIAL INTERVENTION. 2016 13 4275 31 MICROGLIA ACTIVATION IN THE MIDBRAIN OF THE HUMAN NEONATE: THE EFFECT OF PERINATAL HYPOXIC-ISCHEMIC INJURY. PERINATAL HYPOXIA-ISCHEMIA (PHI) IS A MAJOR RISK FACTOR FOR THE DEVELOPMENT OF NEUROPSYCHIATRIC DEFICITS LATER IN LIFE. WE PREVIOUSLY REPORTED THAT AFTER PROLONGED PHI, THE DOPAMINERGIC NEURONS OF THE HUMAN NEONATE SHOWED A DRAMATIC REDUCTION OF TYROSINE HYDROXYLASE (TH) IN THE SUBSTANTIA NIGRA, WITHOUT IMPORTANT SIGNS OF NEURONAL DEGENERATION DESPITE THE SIGNIFICANT REDUCTION IN THEIR CELL SIZE. SINCE MICROGLIA ACTIVATION COULD PRECEDE NEURONAL DEATH, WE NOW INVESTIGATED 2 MICROGLIA ACTIVATION MARKERS, IONIZED CALCIUM-BINDING ADAPTER MOLECULE 1 (IBA1), AND THE PHAGOCYTOSIS MARKER CD68. THE HIGHEST IBA1 IMMUNOREACTIVITY WAS FOUND IN NEONATES WITH NEUROPATHOLOGICAL LESIONS OF SEVERE/ABRUPT PHI, WHILE THE LOWEST IN SUBJECTS WITH MODERATE/PROLONGED OR OLDER PHI. SUBJECTS WITH VERY SEVERE/PROLONGED OR CHRONIC PHI SHOWED AN INCREASED IBA1 EXPRESSION AND VERY ACTIVATED MICROGLIAL MORPHOLOGY. HEAVY ATTACHMENT OF MICROGLIA ON TH NEURONS AND REMARKABLE EXPRESSION OF CD68 WERE ALSO OBSERVED INDICATING PHAGOCYTOSIS IN THIS GROUP. FEMALES APPEAR TO EXPRESS MORE IBA1 THAN MALES, SUGGESTING A GENDER DIFFERENCE IN MICROGLIA MATURATION AND IMMUNE REACTIVITY AFTER PHI INSULT. PHI-INDUCED MICROGLIAL "PRIMING" DURING THE SENSITIVE FOR BRAIN DEVELOPMENT PERINATAL/NEONATAL PERIOD, IN COMBINATION WITH GENETIC OR OTHER EPIGENETIC FACTORS, COULD PREDISPOSE THE SURVIVORS TO NEUROPSYCHIATRIC DISORDERS LATER IN LIFE, POSSIBLY THROUGH A SEXUALLY DIMORPHIC WAY. 2022 14 3177 37 H3K9ME2 REGULATION OF BDNF EXPRESSION IN THE HIPPOCAMPUS AND MEDIAL PREFRONTAL CORTEX IS INVOLVED IN THE DEPRESSIVE-LIKE PHENOTYPE INDUCED BY MATERNAL SEPARATION IN MALE RATS. BACKGROUND: EARLY LIFE STRESS (ELS) INDUCES A DEPRESSIVE-LIKE PHENOTYPE AND INCREASES THE RISK OF DEPRESSION. BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) HAS BEEN CONFIRMED TO BE INVOLVED IN THE PATHOPHYSIOLOGY OF DEPRESSION. HOWEVER, THE MECHANISM BY WHICH ELS ALTERS THE EPIGENETIC REGULATION OF BDNF AND CHANGES SUSCEPTIBILITY TO DEPRESSION HAS NOT BEEN FULLY CLARIFIED. METHODS: THE PRESENT STUDY USED MATERNAL SEPARATION (MS) AND CHRONIC UNPREDICTED MILD STRESS (CUMS) TO ESTABLISH AN MS ANIMAL MODEL AND A DEPRESSIVE ANIMAL MODEL. WE ASSESSED DEPRESSIVE-LIKE BEHAVIOURS, INCLUDING ANHEDONIA, LOCOMOTOR ACTIVITY, ANXIETY-LIKE BEHAVIOUR, AND SPATIAL MEMORY, USING THE SUCROSE PREFERENCE TEST, THE OPEN FIELD TEST, THE ELEVATED PLUS MAZE TEST, AND THE MORRIS WATER MAZE TEST. WE ALSO INVESTIGATED BDNF AND H3K9ME2 EXPRESSION IN THE HIPPOCAMPUS AND MEDIAL PREFRONTAL CORTEX (MPFC) BY IMMUNOHISTOCHEMISTRY, WESTERN BLOTTING, AND QPCR ANALYSIS. ADDITIONALLY, WE USED UNC0642, A SMALL MOLECULE INHIBITOR OF HISTONE METHYLTRANSFERASE (G9A), AS AN INTERVENTION. RESULTS: THE RESULTS SHOWED THAT CUMS INDUCED DEPRESSIVE-LIKE BEHAVIOURS IN RATS AND RESULTED IN INCREASED H3K9ME2 EXPRESSION AND DECREASED BDNF EXPRESSION IN THE HIPPOCAMPUS AND MPFC. MORE IMPORTANTLY, ADULT MS RATS EXPERIENCING CUMS HAD MORE SEVERE DEPRESSIVE BEHAVIOURS, HAD HIGHER EXPRESSION OF H3K9ME2 IN THE HIPPOCAMPUS AND MPFC, AND HAD LOWER EXPRESSION OF BDNF IN THE HIPPOCAMPUS AND MPFC. IN ADDITION, ADMINISTRATION OF THE G9A INHIBITOR REVERSED MOST OF THE CHANGES. CONCLUSIONS: OUR STUDY SUGGESTS THAT ELS CHANGED BDNF AND H3K9ME2 EXPRESSION IN THE RAT BRAIN, RESULTING IN A DEPRESSIVE-LIKE PHENOTYPE. 2021 15 6108 38 THE ENRICHED ENVIRONMENT AMELIORATES CHRONIC UNPREDICTABLE MILD STRESS-INDUCED DEPRESSIVE-LIKE BEHAVIORS AND COGNITIVE IMPAIRMENT BY ACTIVATING THE SIRT1/MIR-134 SIGNALING PATHWAY IN HIPPOCAMPUS. BACKGROUND: CHRONIC UNPREDICTABLE MILD STRESS (CUMS) IS AN IMPORTANT RISK FACTOR FOR DEPRESSION AND COGNITIVE DEFICITS IN HUMANS. ENRICHED ENVIRONMENT (EE) SHOWED A BENEFICIAL EFFECT ON DEPRESSION AND COGNITION BY ENHANCING BRAIN DERIVED NEUROTROPHIC FACTOR (BDNF) EXPRESSION AND SYNAPTIC PLASTICITY. HOWEVER, IT IS STILL NOT CLEARLY UNDERSTOOD WHETHER AN EPIGENETIC MECHANISM IS INVOLVED IN THE BDNF MODULATION AND SYNAPTIC PLASTICITY THAT OCCURS AFTER EE TREATMENT FOR THE DEPRESSIVE-LIKE BEHAVIORS AND COGNITIVE DEFICITS ELICITED BY CUMS. IN THIS STUDY, WE INVESTIGATED THE POSSIBLE MECHANISM OF THE NEUROPROTECTIVE EFFECT OF EE. METHODS: ALL RATS WERE EXPOSED TO THE 5-WEEK CUMS PROCEDURE EXCEPT THE CONTROL GROUP. AFTER CUMS PROCEDURE, SOME RATS WERE STEREOTAXICALLY INJECTED WITH SIRT1 PHARMACOLOGIC INHIBITOR EX527 OR SIRT1 KNOCKING DOWN LENTIVIRUS (SH-SIRT1) IN THE HIPPOCAMPUS FOLLOWED BY EE TREATMENT FOR 3 WEEKS. OTHER RATS WERE DIRECTLY SUBJECTED TO EE TREATMENT WITHOUT STEREOTAXIC INJECTION. BEHAVIORAL TESTS WERE USED TO APPRAISE DEPRESSION AND COGNITION AFTER EE TREATMENT. THEN EPIGENETIC MOLECULES, SYNAPTIC PROTEINS, DENDRITIC SPINE DENSITY AND BRANCHES, AND SYNAPTIC MORPHOLOGY OF THE DORSAL HIPPOCAMPUS WERE DETERMINED. RESULTS: WE FOUND THAT CUMS INDUCED DEPRESSIVE-LIKE BEHAVIORS INCLUDING DECREASED SUCROSE PREFERENCE RATIO, PROLONGED IMMOBILITY AND REDUCED LOCOMOTOR AND EXPLORATORY ACTIVITY; COGNITIVE DEFICITS INCLUDING SPATIAL LEARNING AND MEMORY IMPAIRMENT; REDUCED DENDRITIC SPINE DENSITY AND NUMBER OF BRANCHES; THINNED POSTSYNAPTIC DENSITY; DOWNREGULATED SIRT1/MICRORNA-134 PATHWAY, DECREASED BDNF AND SYNAPTIC PROTEINS INCLUDING SYNAPTOPHYSIN (SYN) AND POSTSYNAPTIC DENSITY PROTEIN 95 (PSD95) EXPRESSION IN THE HIPPOCAMPUS. HOWEVER, THE CUMS-INDUCED DEPRESSIVE-LIKE BEHAVIORS, COGNITIVE DEFICITS, DENDRITIC SPINE DENSITY AND BRANCH NUMBER REDUCTION, POSTSYNAPTIC DENSITY THINNING, SIRT1/MICRORNA-134 PATHWAY DOWNREGULATION, BDNF AND SYNAPTIC PROTEINS REDUCTION, INCLUDING SYNAPTOPHYSIN (SYN) AND POSTSYNAPTIC DENSITY PROTEIN 95 (PSD95), WERE REVERSED BY EE TREATMENT. HOWEVER, DEPRESSIVE-LIKE BEHAVIORS AND COGNITIVE DEFICITS WERE OBSERVED AGAIN IN RATS SUBJECTED TO STEREOTAXIC INJECTION WITH EX527 OR SH-SIRT1. FURTHERMORE, THIS STUDY ALSO FOUND THAT SIRT1/MICRORNA-134 REGULATES THE DOWNSTREAM MOLECULES BDNF, AND THE SYNAPTIC PROTEINS SYN AND PSD95 IN PRIMARY CULTURED HIPPOCAMPAL NEURONS. CONCLUSIONS: THIS STUDY PROVIDES EVIDENCE FOR THE NEUROPROTECTIVE ROLE OF EE ON DEPRESSION AND COGNITIVE DEFICITS BY ACTIVATING THE SIRT1/MICRORNA-134 PATHWAY, WHICH ACCOUNTS FOR THE REGULATION OF SYNAPTIC PROTEINS, INCLUDING BDNF, PSD95 AND SYN, DENDRITIC REMODELING AND ULTRASTRUCTURE CHANGES OF SYNAPSES IN THE HIPPOCAMPUS. 2019 16 1999 35 EPIGENETIC AND NEURONAL ACTIVITY MARKERS SUGGEST THE RECRUITMENT OF THE PREFRONTAL CORTEX AND HIPPOCAMPUS IN THE THREE-HIT MODEL OF DEPRESSION IN MALE PACAP HETEROZYGOUS MICE. DEPRESSION AND ITS INCREASING PREVALENCE CHALLENGE PATIENTS, THE HEALTHCARE SYSTEM, AND THE ECONOMY. WE RECENTLY CREATED A MOUSE MODEL BASED ON THE THREE-HIT CONCEPT OF DEPRESSION. AS GENETIC PREDISPOSITION (FIRST HIT), WE APPLIED PITUITARY ADENYLATE CYCLASE-ACTIVATING POLYPEPTIDE HETEROZYGOUS MICE ON CD1 BACKGROUND. MATERNAL DEPRIVATION MODELED THE EPIGENETIC FACTOR (SECOND HIT), AND THE CHRONIC VARIABLE MILD STRESS WAS THE ENVIRONMENTAL FACTOR (THIRD HIT). FLUOXETINE TREATMENT WAS APPLIED TO TEST THE PREDICTIVE VALIDITY OF OUR MODEL. WE AIMED TO EXAMINE THE DYNAMICS OF THE EPIGENETIC MARKER ACETYL-LYSINE 9 H3 HISTONE (H3K9AC) AND THE NEURONAL ACTIVITY MARKER FOSB IN THE PREFRONTAL CORTEX (PFC) AND HIPPOCAMPUS. FLUOXETINE DECREASED H3K9AC IN PFC IN NON-DEPRIVED ANIMALS, BUT A HISTORY OF MATERNAL DEPRIVATION ABOLISHED THE EFFECT OF STRESS AND SSRI TREATMENT ON H3K9AC IMMUNOREACTIVITY. IN THE HIPPOCAMPUS, STRESS DECREASED, WHILE SSRI INCREASED H3K9AC IMMUNOSIGNAL, UNLIKE IN THE DEPRIVED MICE, WHERE THE OPPOSITE EFFECT WAS DETECTED. FOSB IN STRESS WAS STIMULATED BY FLUOXETINE IN THE PFC, WHILE IT WAS INHIBITED IN THE HIPPOCAMPUS. THE FOSB IMMUNOREACTIVITY WAS ALMOST COMPLETELY ABOLISHED IN THE HIPPOCAMPUS OF THE DEPRIVED MICE. THIS STUDY SHOWED THAT FOSB AND H3K9AC WERE MODULATED IN A TERRITORY-SPECIFIC MANNER BY EARLY LIFE ADVERSITIES AND LATER LIFE STRESS INTERACTING WITH THE EFFECT OF FLUOXETINE THERAPY SUPPORTING THE RELIABILITY OF OUR MODEL. 2022 17 1831 47 EFFECTS OF MATERNAL SEPARATION AND ANTIDEPRESSANT DRUG ON EPIGENETIC REGULATION OF THE BRAIN-DERIVED NEUROTROPHIC FACTOR EXON I PROMOTER IN THE ADULT RAT HIPPOCAMPUS. AIM: EARLY LIFE STRESS CAN INDUCE EPIGENETIC CHANGES THROUGH GENETIC AND ENVIRONMENTAL INTERACTIONS AND IS A RISK FACTOR FOR DEPRESSION. BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) HAS BEEN IMPLICATED IN THE PATHOPHYSIOLOGY OF DEPRESSION AND ANTIDEPRESSANT DRUG ACTION. WE INVESTIGATED EPIGENETIC CHANGES AT THE BDNF EXON I PROMOTER IN THE HIPPOCAMPUS OF ADULT RATS SUBJECTED TO MATERNAL SEPARATION (MS) DURING EARLY LIFE AND TREATED WITH AN ANTIDEPRESSANT DRUG AS ADULTS. METHODS: RAT PUPS WERE SUBJECTED TO MS FROM POSTNATAL DAY 1 TO 21 AND RECEIVED CHRONIC ESCITALOPRAM (ESC) AS ADULTS. WE ASSESSED THE EFFECTS OF MS AND ESC ON BDNF EXON I AND DNA METHYLTRANSFERASES (DNMT) MRNA LEVELS (QUANTITATIVE REVERSE-TRANSCRIPTION POLYMERASE CHAIN REACTION), ACETYLATED HISTONE H3, AND MECP2 BINDING TO THE BDNF PROMOTER I (CHROMATIN IMMUNOPRECIPITATION FOLLOWED BY REAL-TIME POLYMERASE CHAIN REACTION), AND BDNF PROTEIN LEVELS (ENZYME-LINKED IMMUNOSORBENT ASSAY). RESULTS: THE LEVELS OF BDNF PROTEIN, EXON I MRNA, HISTONE H3 ACETYLATION, AND DNMT1 AND DNMT3A MRNA WERE ALTERED IN THE MS GROUP COMPARED WITH THE CONTROL GROUP. SIGNIFICANT DECREASES WERE OBSERVED IN THE BDNF PROTEIN, EXON I MRNA, AND HISTONE H3 ACETYLATION LEVELS AND THERE WERE SIGNIFICANT INCREASES IN DNMT1 AND DNMT3A MRNA LEVELS. THE COMPARISON BETWEEN THE MS + ESC AND MS GROUPS REVEALED SIGNIFICANT INCREASES IN BDNF PROTEIN, EXON I MRNA, AND HISTONE H3 ACETYLATION LEVELS AND SIGNIFICANT DECREASES IN MECP2 AND DNMT1 AND DNMT3A MRNA LEVELS. CONCLUSION: THESE FINDINGS INDICATE THAT MS INDUCED EPIGENETIC CHANGES AT THE BDNF EXON I PROMOTER AND THESE CHANGES WERE PREVENTED BY ANTIDEPRESSANT DRUG TREATMENT DURING ADULTHOOD. 2018 18 1320 38 DEMETHYLATION REGULATION OF BDNF GENE EXPRESSION IN DORSAL ROOT GANGLION NEURONS IS IMPLICATED IN OPIOID-INDUCED PAIN HYPERSENSITIVITY IN RATS. REPEATED ADMINISTRATION OF MORPHINE MAY RESULT IN OPIOID-INDUCED HYPERSENSITIVITY (OIH), WHICH INVOLVES ALTERED EXPRESSION OF NUMEROUS GENES, INCLUDING BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) IN DORSAL ROOT GANGLION (DRG) NEURONS. YET, IT REMAINS UNCLEAR HOW BDNF EXPRESSION IS INCREASED IN DRG NEURONS AFTER REPEATED MORPHINE TREATMENT. DNA METHYLATION IS AN IMPORTANT MECHANISM OF EPIGENETIC CONTROL OF GENE EXPRESSION. IN THE CURRENT STUDY, WE HYPOTHESIZED THAT THE DEMETHYLATION REGULATION OF CERTAIN BDNF GENE PROMOTERS IN DRG NEURONS MAY CONTRIBUTE TO THE DEVELOPMENT OF OIH. REAL-TIME RT-PCR WAS USED TO ASSESS CHANGES IN THE MRNA TRANSCRIPTION LEVELS OF MAJOR BDNF EXONS INCLUDING EXON I, II, IV, VI, AS WELL AS TOTAL BDNF MRNA IN DRGS FROM RATS AFTER REPEATED MORPHINE ADMINISTRATION. THE LEVELS OF EXON IV AND TOTAL BDNF MRNA WERE SIGNIFICANTLY UPREGULATED BY REPEATED MORPHINE ADMINISTRATION, AS COMPARED TO THAT IN SALINE CONTROL GROUP. FURTHER, ELISA ARRAY AND IMMUNOCYTOCHEMISTRY STUDY REVEALED A ROBUST UPREGULATION OF BDNF PROTEIN EXPRESSION IN DRG NEURONS AFTER REPEATED MORPHINE EXPOSURE. CORRESPONDINGLY, THE METHYLATION LEVELS OF BDNF EXON IV PROMOTER SHOWED A SIGNIFICANT DOWNREGULATION BY MORPHINE TREATMENT. IMPORTANTLY, INTRATHECAL ADMINISTRATION OF A BDNF ANTIBODY, BUT NOT CONTROL IGG, SIGNIFICANTLY INHIBITED MECHANICAL HYPERSENSITIVITY THAT DEVELOPED IN RATS AFTER REPEATED MORPHINE TREATMENT. CONVERSELY, INTRATHECAL ADMINISTRATION OF AN INHIBITOR OF DNA METHYLATION, 5-AZA-2'-DEOXYCYTIDINE (5-AZA-DC) MARKEDLY UPREGULATED THE BDNF PROTEIN EXPRESSION IN DRG NEURONS AND ENHANCED THE MECHANICAL ALLODYNIA AFTER REPEATED MORPHINE EXPOSURE. TOGETHER, OUR FINDINGS SUGGEST THAT DEMETHYLATION REGULATION OF BDNF GENE PROMOTER MAY BE IMPLICATED IN THE DEVELOPMENT OF OIH THROUGH EPIGENETIC CONTROL OF BDNF EXPRESSION IN DRG NEURONS. 2016 19 3977 47 LONG-TERM EFFECT OF POST-TRAUMATIC STRESS IN ADOLESCENCE ON DENDRITE DEVELOPMENT AND H3K9ME2/BDNF EXPRESSION IN MALE RAT HIPPOCAMPUS AND PREFRONTAL CORTEX. EXPOSURE TO A HARSH ENVIRONMENT IN EARLY LIFE INCREASES IN THE RISK OF POST-TRAUMATIC STRESS DISORDER (PTSD) OF AN INDIVIDUAL. BRAIN DERIVED NEUROTROPHIC FACTOR (BDNF) PLAYS AN IMPORTANT ROLE IN NEURODEVELOPMENT IN DEVELOPMENTAL STAGES. BOTH CHRONIC AND TRAUMATIC STRESSES INDUCE A DECREASE IN THE LEVEL OF BDNF AND REDUCE NEURAL PLASTICITY, WHICH IS LINKED TO THE PATHOGENESIS OF PTSD. ALSO, STUDIES HAVE SHOWN THAT STRESS ALTERS THE EPIGENETIC MARKER H3K9ME2, WHICH CAN BIND TO THE PROMOTER REGION OF THE BDNF GENE AND REDUCE BDNF PROTEIN LEVEL. HOWEVER, THE LONG-TERM EFFECTS OF TRAUMATIC STRESS DURING ADOLESCENCE ON H3K9ME2, BDNF EXPRESSION AND DENDRITE DEVELOPMENT ARE NOT WELL-KNOWN. THE PRESENT STUDY ESTABLISHED A MODEL OF PTSD IN ADOLESCENT RATS USING AN INESCAPABLE FOOT SHOCK (IFS) PROCEDURE. ANXIETY-LIKE BEHAVIORS, SOCIAL INTERACTION BEHAVIOR AND MEMORY FUNCTION WERE ASSESSED BY THE OPEN FIELD TEST, ELEVATED PLUS MAZE TEST, THREE-CHAMBER SOCIABILITY TEST AND MORRIS WATER MAZE TEST. IN ADDITION, NEURONAL DEVELOPMENT AND H3K9ME2/BDNF EXPRESSION IN HIPPOCAMPUS (HIP) AND PREFRONTAL CORTEX (PFC) WERE EVALUATED BY GOLGI STAINING, WESTERN BLOTTING, QRT-PCR ANALYSIS AND CHIP-QPCR ANALYSIS. ADDITIONALLY, THE UNC0642, A SMALL MOLECULE INHIBITOR OF HISTONE METHYLTRANSFERASE (EHMT2) WAS USED FOR INTERVENTION. THE RESULTS SHOWED THAT THE IFS PROCEDURE INDUCED THE PTSD-LIKE BEHAVIORS IN RATS, RESULTED IN FEWER DENDRITE BRANCHES AND SHORTER DENDRITE LENGTH IN CA1 OF HIP AND PFC, INCREASED H3K9ME2 LEVEL AND DECREASED BDNF EXPRESSION IN HIP AND PFC. ALSO, ALTHOUGH ALL THE CHANGES CAN PERSIST TO ADULTHOOD, UNC0642 ADMINISTRATION RELIEVED MOST OF ALTERATIONS. OUR STUDY SUGGESTS THAT TRAUMATIC STRESS IN ADOLESCENCE LEADS TO IMMEDIATE AND LONG-TERM MENTAL DISORDERS, NEURONAL MORPHOLOGICAL CHANGES, LOWER BDNF LEVEL AND INCREASED H3K9ME2 LEVEL IN THE HIP AND PFC, INDICATING THAT H3K9ME2/BDNF DYSFUNCTION PLAYS A KEY ROLE IN PATHOGENESIS OF PTSD. 2020 20 1803 21 EFFECT OF PROLONGED EMOTIONAL AND PAIN STRESS ON THE CONTENT OF METHYLCYTOSINE-BINDING PROTEIN MECP2 IN NUCLEI OF HIPPOCAMPAL NEURONS IN RATS WITH DIFFERENT EXCITABILITY OF THE NERVOUS SYSTEM. IN RATS WITH LOW EXCITABILITY THRESHOLD OF THE NERVOUS SYSTEM DEMONSTRATING SIGNIFICANT AND PERSISTENT BEHAVIORAL DISORDERS UNDER STRESS CONDITIONS, THE CONTENT OF METHYLCYTOSINE-BINDING PROTEIN MECP2 IN NEURONAL NUCLEI OF HIPPOCAMPAL FIELD CA3 DECREASED OVER 2 WEEKS AFTER LONG-TERM EMOTIONAL AND PAIN STRESS. IT WAS HYPOTHESIZED THAT PROTEIN MECP2 TRIGGERS EPIGENETIC CHANGES IN DNA THAT UNDERLIE "STRESS MEMORY". 2006