1 3325 139 HISTONE DEACETYLASE 2-MEDIATED EPIGENETIC REGULATION IS INVOLVED IN THE EARLY ISOFLURANE EXPOSURE-RELATED INCREASE IN SUSCEPTIBILITY TO ANXIETY-LIKE BEHAVIOUR EVOKED BY CHRONIC VARIABLE STRESS IN MICE. INCREASING STUDIES REPORT THAT PROLONGED OR MULTIPLE ANAESTHETIC EXPOSURES EARLY IN LIFE ARE ASSOCIATED WITH DETRIMENTAL EFFECTS ON BRAIN FUNCTION. ALTHOUGH STUDIES HAVE EVALUATED THE DETRIMENTAL EFFECTS ON NEUROCOGNITIVE FUNCTION, FEW HAVE FOCUSED ON LONG-TERM NEUROPSYCHIATRIC EFFECTS. IN THE PRESENT STUDY, C57BL/6 MICE RECEIVED EITHER THREE NEONATAL ISOFLURANE EXPOSURES OR CONTROL EXPOSURE. STARTING ON POSTNATAL DAY 45, THE MICE WERE EITHER EXPOSED OR NOT TO A CHRONIC VARIABLE STRESS (CVS) PARADIGM, AND CVS-RELATED NEUROPSYCHIATRIC PERFORMANCE WAS EVALUATED USING A SERIES OF BEHAVIOURAL TESTS. THE EXPRESSION LEVELS OF HISTONE 3 LYSINE 9 ACETYLATION (ACETYL-H3K9), BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF), CAMP RESPONSE ELEMENT-BINDING PROTEIN-BINDING PROTEIN, AND HISTONE DEACETYLASES 1-4 IN THE AMYGDALA WERE MEASURED BY IMMUNOBLOTTING OR IMMUNOHISTOCHEMISTRY ANALYSIS. IN MICE WITH NEONATAL ISOFLURANE EXPOSURE, THE EFFECTS OF SODIUM BUTYRATE (NAB), A COMMONLY USED HDAC INHIBITOR, WERE EXAMINED ON CVS-RELATED BEHAVIOURAL AND MOLECULAR ALTERATIONS. THE RESULTS SHOWED THAT REPEATED NEONATAL ISOFLURANE EXPOSURE DID NOT AFFECT INNATE DEPRESSION-LIKE AND ANXIETY-LIKE BEHAVIOURS UNDER NON-STRESS CONDITIONS BUT FACILITATED THE CVS-INDUCED ANXIETY-LIKE BEHAVIOURAL PHENOTYPE. INCREASED HDAC2 EXPRESSION IN THE AMYGDALA WAS ASSOCIATED WITH AN INCREASE IN THE CVS-INDUCED REPRESSION OF ACETYL-H3K9 AND BDNF EXPRESSION AND AN ENHANCED CVS-EVOKED ANXIETY-LIKE BEHAVIOURAL PHENOTYPE IN MICE NEONATAL ISOFLURANE EXPOSURE. NAB SIGNIFICANTLY DECREASED THE CVS-INDUCED ANXIETY LEVEL BY ELEVATING ACETYL-H3K9 AND BDNF EXPRESSION. THESE RESULTS SUGGESTED THAT EARLY ANAESTHESIA EXPOSURE FACILITATED CHRONIC STRESS-INDUCED NEUROPSYCHIATRIC OUTCOMES, AND THE HDAC2-RELATED EPIGENETIC DYSREGULATION OF BDNF GENE EXPRESSION IS INVOLVED IN THE UNDERLYING MECHANISM. 2021 2 5152 40 PPM1F IN DENTATE GYRUS MODULATES ANXIETY-RELATED BEHAVIORS BY REGULATING BDNF EXPRESSION VIA AKT/JNK/P-H3S10 PATHWAY. ANXIETY IS A SERIOUS PSYCHIATRIC DISORDER, WITH A HIGHER INCIDENCE RATE IN WOMEN THAN IN MEN. PROTEIN PHOSPHATASE MG(2+)/MN(2+)-DEPENDENT 1F (PPM1F), A SERINE/THREONINE PHOSPHATASE, HAS BEEN SHOWN TO HAVE MULTIPLE BIOLOGICAL AND CELLULAR FUNCTIONS. HOWEVER, THE EFFECTS OF PPM1F AND ITS NEURONAL SUBSTRATES ON ANXIETY REMAIN LARGELY UNCLEAR. IN THIS STUDY, WE SHOWED THAT CHRONIC RESTRAINT STRESS (CRS) INDUCED ANXIETY-RELATED BEHAVIORS ONLY IN FEMALE MICE, WHILE ACUTE RESTRAINT STRESS (ARS) PRODUCED ANXIETY-RELATED BEHAVIORS IN BOTH MALE AND FEMALE MICE IN LIGHT-DARK AND ELEVATED PLUS MAZE TESTS AND INDUCED UPREGULATION OF PPM1F AND DOWNREGULATION OF BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) EXPRESSION IN THE HIPPOCAMPUS. ADENO-ASSOCIATED VIRUS-MEDIATED OVEREXPRESSION OF PPM1F OR CONDITIONAL KNOCKOUT OF BDNF IN DENTATE GYRUS (DG) LED TO A MORE PRONOUNCED ANXIETY-RELATED BEHAVIOR IN FEMALE THAN IN MALE MICE AS INDICATED BY THE BEHAVIORAL EVALUATIONS. MEANWHILE, OVEREXPRESSION OF PPM1F IN THE DG DECREASED TOTAL BDNF EXON-SPECIFIC MESSENGER RNA EXPRESSION IN THE HIPPOCAMPUS WITH THE DECREASED BINDING ACTIVITY OF PHOSPHORYLATED H3S10 TO ITS INDIVIDUAL PROMOTERS IN FEMALE MICE. FURTHERMORE, WE IDENTIFIED THAT OVEREXPRESSION OF PPM1F DECREASED THE PHOSPHORYLATION LEVELS OF AKT AND JNK IN THE HIPPOCAMPUS OF FEMALE MICE. THESE RESULTS MAY SUGGEST THAT PPM1F REGULATES ANXIETY-RELATED BEHAVIORS BY MODULATING BDNF EXPRESSION AND H3S10 PHOSPHORYLATION-MEDIATED EPIGENETIC MODIFICATION, WHICH MAY BE SERVED AS POTENTIALLY PATHOLOGICAL GENES ASSOCIATED WITH ANXIETY OR OTHER MENTAL DISEASES. 2021 3 5339 29 QUETIAPINE TREATMENT REVERSES DEPRESSIVE-LIKE BEHAVIOR AND REDUCES DNA METHYLTRANSFERASE ACTIVITY INDUCED BY MATERNAL DEPRIVATION. STRESS IN EARLY LIFE HAS BEEN APPOINTED AS AN IMPORTANT PHENOMENON IN THE ONSET OF DEPRESSION AND POOR RESPONSE TO TREATMENT WITH CLASSICAL ANTIDEPRESSANTS. FURTHERMORE, CHILDHOOD TRAUMA TRIGGERS EPIGENETIC CHANGES, WHICH ARE ASSOCIATED WITH THE PATHOPHYSIOLOGY OF MAJOR DEPRESSIVE DISORDER (MDD). TREATMENT WITH ATYPICAL ANTIPSYCHOTICS SUCH AS QUETIAPINE, EXERTS THERAPEUTIC EFFECT FOR MDD PATIENTS AND INDUCES EPIGENETIC CHANGES. THIS STUDY AIMED TO ANALYZE THE EFFECT OF CHRONIC TREATMENT WITH QUETIAPINE (20MG/KG) ON DEPRESSIVE-LIKE BEHAVIOR OF RATS SUBMITTED TO MATERNAL DEPRIVATION (MD), AS WELL AS THE ACTIVITY OF HISTONE ACETYLATION BY THE ENZYMES HISTONE ACETYL TRANSFERASES (HAT) AND DEACETYLASES (HDAC) AND DNA METHYLATION, THROUGH DNA METHYLTRANSFERASE ENZYME (DNMT) IN THE PREFRONTAL CORTEX (PFC), NUCLEUS ACCUMBENS (NAC) AND HIPPOCAMPUS. MATERNALLY DEPRIVED RATS HAD A DEPRESSIVE-LIKE BEHAVIOR IN THE FORCED SWIMMING TEST AND AN INCREASE IN THE HDAC AND DNMT ACTIVITIES IN THE HIPPOCAMPUS AND NAC. TREATMENT WITH QUETIAPINE REVERSED DEPRESSIVE-LIKE BEHAVIOR AND REDUCED THE DNMT ACTIVITY IN THE HIPPOCAMPUS. THIS IS THE FIRST STUDY TO SHOW THE ANTIDEPRESSANT-LIKE EFFECT OF QUETIAPINE IN ANIMALS SUBJECTED TO MD AND A PROTECTIVE EFFECT BY QUETIAPINE IN REDUCING EPIGENETIC CHANGES INDUCED BY STRESS IN EARLY LIFE. THESE RESULTS REINFORCE AN IMPORTANT ROLE OF QUETIAPINE AS THERAPY FOR MDD. 2017 4 5832 35 STRESS-INDUCED EPIGENETIC CHANGES IN HIPPOCAMPAL MKP-1 PROMOTE PERSISTENT DEPRESSIVE BEHAVIORS. CHRONIC STRESS INDUCES PERSISTENT DEPRESSIVE BEHAVIORS. STRESS-INDUCED TRANSCRIPTIONAL ALTERATION OVER THE HOMEOSTATIC RANGE IN STRESS HORMONE-SENSITIVE BRAIN REGIONS IS BELIEVED TO UNDERLIE LONG-LASTING DEPRESSIVE BEHAVIORS. HOWEVER, THE DETAILED MECHANISMS BY WHICH CHRONIC STRESS CAUSES THOSE ADAPTIVE CHANGES ARE NOT CLEARLY UNDERSTOOD. IN THE PRESENT STUDY, WE INVESTIGATED WHETHER EPIGENETIC CHANGES REGULATE STRESS-INDUCED DEPRESSIVE BEHAVIORS. WE FOUND THAT CHRONIC STRESS IN MICE DOWNREGULATES THE EPIGENETIC FACTORS HDAC2 AND SUV39H1 IN THE HIPPOCAMPUS. A SERIES OF FOLLOW-UP ANALYSES INCLUDING CHIP ASSAY AND SIRNA-MEDIATED FUNCTIONAL ANALYSES REVEAL THAT GLUCOCORTICOIDS RELEASED BY STRESS CUMULATIVELY INCREASE MKP-1 EXPRESSION IN THE HIPPOCAMPUS, AND INCREASED MKP-1 THEN DEBILITATES P-CREB AND PPARGAMMA, WHICH IN TURN SUPPRESS THE EPIGENETIC FACTORS HDAC2 AND SUV39H1. FURTHERMORE, HDAC2 AND SUV39H1 NORMALLY SUPPRESS THE TRANSCRIPTION OF THE MKP-1, AND THEREFORE THE REDUCED EXPRESSION OF HDAC2 AND SUV39H1 INCREASES MKP-1 EXPRESSION. ACCORDINGLY, REPEATED STRESS PROGRESSIVELY STRENGTHENS A VICIOUS CYCLE OF THE MKP-1 SIGNALING CASCADE THAT FACILITATES DEPRESSIVE BEHAVIORS. THESE RESULTS SUGGEST THAT THE HIPPOCAMPAL STRESS ADAPTATION SYSTEM COMPRISING HDAC2/SUV39H1-REGULATED MKP-1 SIGNALING NETWORK DETERMINES THE VULNERABILITY TO CHRONIC STRESS AND THE MAINTENANCE OF DEPRESSIVE BEHAVIORS. 2019 5 5205 36 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 6 2886 27 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 7 905 32 CHRONIC EXPOSURE TO CANNABINOIDS DURING ADOLESCENCE CAUSES LONG-LASTING BEHAVIORAL DEFICITS IN ADULT MICE. REGULAR USE OF MARIJUANA DURING ADOLESCENCE ENHANCES THE RISK OF LONG-LASTING NEUROBIOLOGICAL CHANGES IN ADULTHOOD. THE PRESENT STUDY WAS AIMED AT ASSESSING THE EFFECT OF LONG-TERM ADMINISTRATION OF THE SYNTHETIC CANNABINOID WIN55212.2 DURING ADOLESCENCE IN YOUNG ADULT MICE. ADOLESCENT MICE AGED 5 WEEKS WERE SUBJECTED DAILY TO THE PHARMACOLOGICAL ACTION OF WIN55212.2 FOR 3 WEEKS AND WERE THEN LEFT UNDISTURBED IN THEIR HOME CAGE FOR A 5-WEEK PERIOD AND FINALLY EVALUATED BY BEHAVIORAL TESTING. MICE THAT RECEIVED THE DRUG DURING ADOLESCENCE SHOWED MEMORY IMPAIRMENT IN THE MORRIS WATER MAZE, AS WELL AS A DOSE-DEPENDENT MEMORY IMPAIRMENT IN FEAR CONDITIONING. IN ADDITION, THE ADMINISTRATION OF 3 MG/KG WIN55212.2 IN ADOLESCENCE INCREASED ADULT HIPPOCAMPAL AEA LEVELS AND PROMOTED DNA HYPERMETHYLATION AT THE INTRAGENIC REGION OF THE INTRACELLULAR SIGNALING MODULATOR RGS7, WHICH WAS ACCOMPANIED BY A LOWER RATE OF MRNA TRANSCRIPTION OF THIS GENE, SUGGESTING A POTENTIAL CAUSAL RELATION. ALTHOUGH THE CONCRETE MECHANISMS UNDERLYING THE BEHAVIORAL OBSERVATIONS REMAIN TO BE ELUCIDATED, WE DEMONSTRATE THAT LONG-TERM ADMINISTRATION OF 3 MG/KG OF WIN DURING ADOLESCENCE LEADS TO INCREASED ENDOCANNABINOID LEVELS AND ALTERED RGS7 EXPRESSION IN ADULTHOOD AND ESTABLISH A POTENTIAL LINK TO EPIGENETIC CHANGES. 2017 8 889 30 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 9 2246 32 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 10 195 28 ACF CHROMATIN-REMODELING COMPLEX MEDIATES STRESS-INDUCED DEPRESSIVE-LIKE BEHAVIOR. IMPROVED TREATMENT FOR MAJOR DEPRESSIVE DISORDER (MDD) REMAINS ELUSIVE BECAUSE OF THE LIMITED UNDERSTANDING OF ITS UNDERLYING BIOLOGICAL MECHANISMS. IT IS LIKELY THAT STRESS-INDUCED MALADAPTIVE TRANSCRIPTIONAL REGULATION IN LIMBIC NEURAL CIRCUITS CONTRIBUTES TO THE DEVELOPMENT OF MDD, POSSIBLY THROUGH EPIGENETIC FACTORS THAT REGULATE CHROMATIN STRUCTURE. WE ESTABLISH THAT PERSISTENT UPREGULATION OF THE ACF (ATP-UTILIZING CHROMATIN ASSEMBLY AND REMODELING FACTOR) ATP-DEPENDENT CHROMATIN-REMODELING COMPLEX, OCCURRING IN THE NUCLEUS ACCUMBENS OF STRESS-SUSCEPTIBLE MICE AND DEPRESSED HUMANS, IS NECESSARY FOR STRESS-INDUCED DEPRESSIVE-LIKE BEHAVIORS. WE FOUND THAT ALTERED ACF BINDING AFTER CHRONIC STRESS WAS CORRELATED WITH ALTERED NUCLEOSOME POSITIONING, PARTICULARLY AROUND THE TRANSCRIPTION START SITES OF AFFECTED GENES. THESE ALTERATIONS IN ACF BINDING AND NUCLEOSOME POSITIONING WERE ASSOCIATED WITH REPRESSED EXPRESSION OF GENES IMPLICATED IN SUSCEPTIBILITY TO STRESS. TOGETHER, OUR FINDINGS IDENTIFY THE ACF CHROMATIN-REMODELING COMPLEX AS A CRITICAL COMPONENT IN THE DEVELOPMENT OF SUSCEPTIBILITY TO DEPRESSION AND IN REGULATING STRESS-RELATED BEHAVIORS. 2015 11 433 38 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 12 2672 39 ETHANOL-INDUCED EPIGENETIC REGULATIONS AT THE BDNF GENE IN C57BL/6J MICE. HIGH ETHANOL INTAKE IS WELL KNOWN TO INDUCE BOTH ANXIOLYTIC AND ANXIOGENIC EFFECTS, IN CORRELATION WITH CHROMATIN REMODELING IN THE AMYGDALOID BRAIN REGION AND DEFICITS IN CELL PROLIFERATION AND SURVIVAL IN THE HIPPOCAMPUS OF RODENTS. WHETHER ONLY MODERATE BUT CHRONIC ETHANOL INTAKE IN C57BL/6J MICE COULD ALSO HAVE AN IMPACT ON CHROMATIN REMODELING AND NEUROPLASTICITY WAS ADDRESSED HERE. CHRONIC ETHANOL CONSUMPTION IN A FREE CHOICE PARADIGM WAS FOUND TO INDUCE MARKED CHANGES IN THE EXPRESSION OF GENES IMPLICATED IN NEURAL DEVELOPMENT AND HISTONE POST-TRANSLATIONAL MODIFICATIONS IN THE MOUSE HIPPOCAMPUS. TRANSCRIPTS ENCODING NEURAL BHLH ACTIVATORS AND THOSE FROM BDNF EXONS II, III AND VI WERE UPREGULATED, WHEREAS THOSE FROM BDNF EXON VIII AND HDACS WERE DOWNREGULATED BY ETHANOL COMPARED WITH WATER CONSUMPTION. THESE ETHANOL-INDUCED CHANGES WERE ASSOCIATED WITH ENRICHMENT IN BOTH ACETYLATED H3 AT BDNF PROMOTER PVI AND TRIMETHYLATED H3 AT PII AND PIII. CONVERSELY, ACETYLATED H3 AT PIII AND PVIII AND TRIMETHYLATED H3 AT PVIII WERE DECREASED IN ETHANOL-EXPOSED MICE. IN PARALLEL, HIPPOCAMPAL BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) LEVELS AND TRKB-MEDIATED NEUROGENESIS IN THE DENTATE GYRUS WERE SIGNIFICANTLY ENHANCED BY ETHANOL CONSUMPTION. THESE RESULTS SUGGEST THAT, IN C57BL/6J MICE, CHRONIC AND MODERATE ETHANOL INTAKE PRODUCES MARKED EPIGENETIC CHANGES UNDERLYING BDNF OVEREXPRESSION AND DOWNSTREAM HIPPOCAMPAL NEUROGENESIS. 2015 13 5713 39 SIRT2 INHIBITION REVERSES ANHEDONIA IN THE VGLUT1+/- DEPRESSION MODEL. SOME HISTONE DEACETYLASE (HDACS) ENZYMES HAVE BEEN PROPOSED AS EPIGENETIC TARGETS INVOLVED IN THE PATHOPHYSIOLOGY OF DEPRESSION AND ANTIDEPRESSANT-LIKE ACTION. AMONG THEM, WE HAVE RECENTLY IDENTIFIED SIRT2, A CLASS III NAD(+)-DEPENDENT HDAC, AS BEING OPPOSITELY REGULATED BY STRESS AND ANTIDEPRESSANTS. MOREOVER, SIRT2 INHIBITION HAS SHOWN ANTIANHEDONIC-LIKE ACTION IN THE CHRONIC MILD STRESS MODEL OF DEPRESSION. HERE WE HAVE EXTENDED THE STUDY USING AN ALTERNATIVE MODEL OF DEPRESSION BASED IN A GENETIC MANIPULATION OF GLUTAMATE FUNCTION. SPECIFICALLY, MICE HETEROZYGOUS FOR THE VESICULAR GLUTAMATE TRANSPORTER 1 (VGLUT1+/-) WERE USED. FIRSTLY, MRNA EXPRESSION OF THE DIFFERENT MEMBERS OF THE HDAC SUPERFAMILY IN THE PREFRONTAL CORTEX (PFC) OF VGLUT1+/- MICE AND WT LITTERMATES WERE STUDIED BY RT-PCR. SECONDLY, THE EFFECT OF REPEATED TREATMENT WITH THE SELECTIVE SIRT2 INHIBITOR 33I AND THE ANTIDEPRESSANT IMIPRAMINE ON ANHEDONIC BEHAVIOUR OF VGLUT1+/- MICE WAS STUDIED BY WEEKLY MONITORING OF SUCROSE INTAKE. FURTHER, THE INTERACTION OF 33I TOWARDS SPECIFIC MONOAMINERGIC TARGETS SUCH AS SEROTONIN OR NORADRENALINE TRANSPORTERS AS WELL AS THE MONOAMINOOXIDASE ENZYME WAS STUDIED. THE MRNA OCCURANCE OF THE DIFFERENT MEMBERS OF HDAC SUPERFAMILY WAS NOT ALTERED IN THE PFC OF VGLUT1+/- MICE. WHILE REPEATED IMIPRAMINE SHOWED AN ANTI-ANHEDONIC ACTION IN BOTH VGLUT1+/- AND WT, THE SELECTIVE SIRT2 INHIBITOR 33I FULLY REVERSED ANHEDONIA OF VGLUT1+/-. FURTHER, 33I SHOWED NO INTERACTION WITH THE ABOVE MENTIONED MONOAMINERGIC MOLECULAR TARGETS. THESE RESULTS CONFIRM THAT SIRT2 INHIBITION IS ABLE TO REVERSE ANHEDONIA IN DIFFERENT ANIMAL MODELS AND HIGHLIGHT THE NEED TO FURTHER INVESTIGATE THE ROLE OF SIRT2 INHIBITORS AS NEW ANTIDEPRESSANT AGENTS. 2017 14 4499 36 MORPHINE WITHDRAWAL PRODUCES ERK-DEPENDENT AND ERK-INDEPENDENT EPIGENETIC MARKS IN NEURONS OF THE NUCLEUS ACCUMBENS AND LATERAL SEPTUM. EPIGENETIC CHANGES SUCH AS COVALENT MODIFICATIONS OF HISTONE PROTEINS REPRESENT COMPLEX MOLECULAR SIGNATURES THAT PROVIDE A CELLULAR MEMORY OF PREVIOUSLY EXPERIENCED STIMULI WITHOUT IRREVERSIBLE CHANGES OF THE GENETIC CODE. IN THIS STUDY WE SHOW THAT NEW GENE EXPRESSION INDUCED IN VIVO BY MORPHINE WITHDRAWAL OCCURS WITH CONCOMITANT EPIGENETIC MODIFICATIONS IN BRAIN REGIONS CRITICALLY INVOLVED IN DRUG-DEPENDENT BEHAVIORS. WE FOUND THAT NALOXONE-PRECIPITATED WITHDRAWAL, BUT NOT CHRONIC MORPHINE ADMINISTRATION, CAUSED A STRONG INDUCTION OF PHOSPHO-HISTONE H3 IMMUNOREACTIVITY IN THE NUCLEUS ACCUMBENS (NAC) SHELL/CORE AND IN THE LATERAL SEPTUM (LS), A CHANGE THAT WAS ACCOMPANIED BY AUGMENTED H3 ACETYLATION (LYS14) IN NEURONS OF THE NAC SHELL. MORPHINE WITHDRAWAL INDUCED THE PHOSPHORYLATION OF THE EPIGENETIC FACTOR METHYL-CPG-BINDING PROTEIN 2 (MECP2) IN SER421 BOTH IN THE LS AND THE NAC SHELL. THESE EPIGENETIC CHANGES WERE ACCOMPANIED BY THE ACTIVATION OF MEMBERS OF THE ERK PATHWAY AS WELL AS INCREASED EXPRESSION OF THE IMMEDIATE EARLY GENES (IEG) C-FOS AND ACTIVITY-REGULATED CYTOSKELETON-ASSOCIATED PROTEIN (ARC/ARG3.1). USING A PHARMACOLOGICAL APPROACH, WE FOUND THAT H3 PHOSPHORYLATION AND IEG EXPRESSION WERE PARTIALLY DEPENDENT ON ERK ACTIVATION, WHILE MECP2 PHOSPHORYLATION WAS FULLY ERK-INDEPENDENT. THESE FINDINGS PROVIDE NEW IMPORTANT INFORMATION ON THE ROLE OF THE ERK PATHWAY IN THE REGULATION OF EPIGENETIC MARKS AND GENE EXPRESSION THAT MAY CONCUR TO REGULATE IN VIVO THE CELLULAR CHANGES UNDERLYING THE ONSET OF THE OPIOID WITHDRAWAL SYNDROME. 2013 15 5838 41 STRIATAL SHATI/NAT8L-BDNF PATHWAYS DETERMINE THE SENSITIVITY TO SOCIAL DEFEAT STRESS IN MICE THROUGH EPIGENETIC REGULATION. THE GLOBAL NUMBER OF PATIENTS WITH DEPRESSION INCREASES IN CORRELATION TO EXPOSURE TO SOCIAL STRESS. CHRONIC STRESS DOES NOT TRIGGER DEPRESSION IN ALL INDIVIDUALS, AS SOME REMAIN RESILIENT. THE UNDERLYING MOLECULAR MECHANISMS THAT CONTRIBUTE TO STRESS SENSITIVITY HAVE BEEN POORLY UNDERSTOOD, ALTHOUGH REVEALING THE REGULATION OF STRESS SENSITIVITY COULD HELP DEVELOP TREATMENTS FOR DEPRESSION. WE PREVIOUSLY FOUND THAT STRIATAL SHATI/NAT8L, AN N-ACETYLTRANSFERASE, WAS INCREASED IN A DEPRESSION MOUSE MODEL. WE INVESTIGATED THE ROLES OF SHATI/NAT8L IN STRESS SENSITIVITY IN MICE AND FOUND THAT SHATI/NAT8L AND BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) LEVELS IN THE DORSAL STRIATUM WERE INCREASED IN STRESS-SUSCEPTIBLE MICE BUT NOT IN RESILIENT MICE EXPOSED TO REPEATED SOCIAL DEFEAT STRESS (RSDS). KNOCKDOWN OF SHATI/NAT8L IN THE DORSAL STRIATUM INDUCED RESILIENCE TO RSDS. IN ADDITION, BLOCKADE OF BDNF SIGNALING IN THE DORSAL STRIATUM BY ANA-12, A BDNF-SPECIFIC RECEPTOR TROPOMYOSIN-RECEPTOR-KINASE B (TRKB) INHIBITOR, ALSO INDUCED RESILIENCE TO STRESS. SHATI/NAT8L IS CORRELATED WITH BDNF EXPRESSION AFTER RSDS, AND BDNF IS DOWNSTREAM OF SHATI/NAT8L PATHWAYS IN THE DORSAL STRIATUM; SHATI/NAT8L IS EPIGENETICALLY REGULATED BY BDNF VIA HISTONE ACETYLATION. OUR RESULTS DEMONSTRATE THAT STRIATAL SHATI/NAT8L-BDNF PATHWAYS DETERMINE STRESS SENSITIVITY THROUGH EPIGENETIC REGULATION. THE STRIATAL SHATI/NAT8L-BDNF PATHWAY COULD BE A NOVEL TARGET FOR TREATMENTS OF DEPRESSION AND COULD ESTABLISH A NOVEL THERAPEUTIC STRATEGY FOR DEPRESSION PATIENTS. 2021 16 989 40 CHRONIC SOCIAL DEFEAT STRESS DIFFERENTIALLY REGULATES THE EXPRESSION OF BDNF TRANSCRIPTS AND EPIGENETIC MODIFYING ENZYMES IN SUSCEPTIBLE AND RESILIENT MICE. OBJECTIVES: ALTHOUGH STRESS IS CONSIDERED A PRIMARY RISK FACTOR FOR NEUROPSYCHIATRIC DISORDERS, A MAJORITY OF INDIVIDUALS ARE RESILIENT TO THE EFFECTS OF STRESS EXPOSURE AND SUCCESSFULLY ADAPT TO ADVERSE LIFE EVENTS, WHILE OTHERS, THE SO-CALLED SUSCEPTIBLE INDIVIDUALS, MAY HAVE PROBLEMS TO PROPERLY ADAPT TO ENVIRONMENTAL CHANGES. HOWEVER, THE MECHANISMS UNDERLYING THESE DIFFERENT RESPONSES TO STRESS EXPOSURE ARE POORLY UNDERSTOOD.METHODS: ADULT MALE C57BL/6J MICE WERE EXPOSED TO CHRONIC SOCIAL DEFEAT STRESS PROTOCOL AND LEVELS OF BRAIN DERIVED NEUROTROPHIC FACTOR (BDNF) TRANSCRIPTS AND EPIGENETIC MODIFYING ENZYMES WERE ANALYSED BY REAL-TIME PCR IN THE HIPPOCAMPUS (HPC) AND PREFRONTAL CORTEX (PFC) OF SUSCEPTIBLE AND RESILIENT MICE.RESULTS: WE FOUND A SELECTIVE REDUCTION OF BDNF-6 TRANSCRIPT IN THE HPC AND AN INCREASE OF BDNF-4 TRANSCRIPT IN THE PFC OF SUSCEPTIBLE MICE. MOREOVER, SUSCEPTIBLE MICE SHOWED A SELECTIVE REDUCTION OF THE G9A MRNA LEVELS IN THE HPC, WHILE HDAC-5 AND DNMT3A MRNA LEVELS WERE SPECIFICALLY REDUCED IN THE PFC.CONCLUSIONS: OVERALL, OUR RESULTS, SHOWING A DIFFERENT EXPRESSION OF BDNF TRANSCRIPTS AND EPIGENETIC MODIFYING ENZYMES IN SUSCEPTIBLE AND RESILIENT MICE, SUGGEST THAT STRESS RESILIENCE IS NOT SIMPLY A LACK OF ACTIVATION OF STRESS-RELATED PATHWAYS, BUT IS RELATED TO THE ACTIVATION OF ADDITIONAL DIFFERENT SPECIFIC MECHANISMS. 2019 17 5065 32 PHOTOPERIOD-INDUCED NEUROTRANSMITTER PLASTICITY DECLINES WITH AGING: AN EPIGENETIC REGULATION? NEUROPLASTICITY HAS CLASSICALLY BEEN UNDERSTOOD TO ARISE THROUGH CHANGES IN SYNAPTIC STRENGTH OR SYNAPTIC CONNECTIVITY. A NEWLY DISCOVERED FORM OF NEUROPLASTICITY, NEUROTRANSMITTER SWITCHING, INVOLVES CHANGES IN NEUROTRANSMITTER IDENTITY. CHRONIC EXPOSURE TO DIFFERENT PHOTOPERIODS ALTERS THE NUMBER OF DOPAMINE (TYROSINE HYDROXYLASE, TH+) AND SOMATOSTATIN (SST+) NEURONS IN THE PARAVENTRICULAR NUCLEUS (PAVN) OF THE HYPOTHALAMUS OF ADULT RATS AND RESULTS IN DISCRETE BEHAVIORAL CHANGES. HERE, WE INVESTIGATE WHETHER PHOTOPERIOD-INDUCED NEUROTRANSMITTER SWITCHING PERSISTS DURING AGING AND WHETHER EPIGENETIC MECHANISMS OF HISTONE ACETYLATION AND DNA METHYLATION MAY CONTRIBUTE TO THIS NEUROTRANSMITTER PLASTICITY. WE SHOW THAT THIS PLASTICITY IN RATS IS ROBUST AT 1 AND AT 3 MONTHS BUT REDUCED IN TH+ NEURONS AT 12 MONTHS AND COMPLETELY ABOLISHED IN BOTH TH+ AND SST+ NEURONS BY 18 MONTHS. DE NOVO EXPRESSION OF DNMT3A CATALYZING DNA METHYLATION AND ANTI-ACETYLH3 ASSESSING HISTONE 3 ACETYLATION WERE OBSERVED FOLLOWING SHORT-DAY PHOTOPERIOD EXPOSURE IN BOTH TH+ AND SST+ NEURONS AT 1 AND 3 MONTHS WHILE AN OVERALL INCREASE IN DNMT3A IN SST+ NEURONS PARALLELED NEUROPLASTICITY REDUCTION AT 12 AND 18 MONTHS. HISTONE ACETYLATION INCREASED IN TH+ NEURONS AND DECREASED IN SST+ NEURONS FOLLOWING SHORT-DAY EXPOSURE AT 3 MONTHS WHILE THE TOTAL NUMBER OF ANTI-ACETYLH3+ PAVN NEURONS REMAINED CONSTANT. RECIPROCAL HISTONE ACETYLATION IN TH+ AND SST+ NEURONS INDICATES THE IMPORTANCE OF STUDYING EPIGENETIC REGULATION AT THE CIRCUIT LEVEL FOR IDENTIFIED CELL PHENOTYPES. THE FINDINGS MAY BE USEFUL FOR DEVELOPING APPROACHES FOR NONINVASIVE TREATMENT OF DISORDERS CHARACTERIZED BY NEUROTRANSMITTER DYSFUNCTION. 2020 18 3833 43 INVOLVEMENT OF THE DYNORPHIN/KOR SYSTEM ON THE NOCICEPTIVE, EMOTIONAL AND COGNITIVE MANIFESTATIONS OF JOINT PAIN IN MICE. JOINT PAIN IS A MAJOR CLINICAL PROBLEM MAINLY ASSOCIATED TO OSTEOARTHRITIS, AND CHARACTERIZED BY ARTICULAR CARTILAGE DEGRADATION RESULTING IN A COMPLEX CHRONIC PAIN STATE THAT INCLUDES NOCICEPTIVE, EMOTIONAL AND COGNITIVE MANIFESTATIONS. MEMORY IMPAIRMENT, DEPRESSIVE- AND ANXIETY-LIKE SYMPTOMS HAVE BEEN REPORTED TO BE ASSOCIATED WITH CHRONIC PAIN, LEADING TO A DECREASE OF LIFE QUALITY. IN THIS STUDY, WE EVALUATED THE INVOLVEMENT OF THE ENDOGENOUS DYNORPHIN/KAPPA OPIOID RECEPTOR (KOR) SYSTEM ON THE NOCICEPTIVE, EMOTIONAL, COGNITIVE, NEUROCHEMICAL AND EPIGENETIC MANIFESTATIONS OF JOINT PAIN. THE MURINE MODEL OF MONOSODIUM IODOACETATE (MIA) WAS USED TO INDUCE JOINT PAIN IN KNOCKOUT MICE FOR KOR (KOR-KO), PRODYNORPHIN (PDYN-KO) AND THEIR WILD-TYPE (WT) LITTERMATES. KOR-KO AND PDYN-KO MICE DEVELOPED MECHANICAL ALLODYNIA AFTER INTRA-ARTICULAR INJECTION OF MIA. THIS ALLODYNIA WAS SIGNIFICANTLY INCREASED IN BOTH KOR-KO AND PDYN-KO WHEN COMPARED TO WT MICE. ACCORDINGLY, BOTH MUTANTS SHOWED INCREASED MICROGLIAL ACTIVATION ON THE LUMBAR SECTION OF THE SPINAL CORD AFTER MIA. THE EMOTIONAL RESPONSES WERE EVALUATED BY MEASURING ANXIETY-LIKE BEHAVIOUR IN THE ELEVATED PLUS MAZE AND ANHEDONIA AS DEPRESSIVE-LIKE BEHAVIOUR, AND COGNITIVE ALTERATIONS IN THE OBJECT RECOGNITION PARADIGM. EMOTIONAL AND COGNITIVE IMPAIRMENTS AFTER JOINT PAIN WERE DIFFERENTLY MODIFIED IN KOR-KO AND PDYN-KO MICE. ALTERATIONS OF CORTICOTROPIN-RELEASING FACTOR (CRF) ON THE AMYGDALA AND HIPPOCAMPUS AND DOWN REGULATION OF HISTONE 3 ACETYLATION ON THE AMYGDALA SUGGEST A POSSIBLE MECHANISM TO EXPLAIN THESE EMOTIONAL AND COGNITIVE MANIFESTATIONS. OUR RESULTS REVEAL A SPECIFIC INVOLVEMENT OF THE DYNORPHIN/KOR SYSTEM ON JOINT PAIN MANIFESTATIONS THAT ARE USUALLY ASSOCIATED TO OSTEOARTHRITIS. 2017 19 6602 24 TWO KINDS OF TRANSCRIPTION FACTORS MEDIATE CHRONIC MORPHINE-INDUCED DECREASE IN MIR-105 IN MEDIAL PREFRONTAL CORTEX OF RATS. CHRONIC MORPHINE ADMINISTRATION ALTERS GENE EXPRESSION IN DIFFERENT BRAIN REGIONS, AN EFFECT WHICH MAY CONTRIBUTE TO PLASTIC CHANGES ASSOCIATED WITH ADDICTIVE BEHAVIOR. THIS CHANGE IN GENE EXPRESSION IS MOST POSSIBLY MEDIATED BY ADDICTIVE DRUG-INDUCED EPIGENETIC REMODELING OF GENE EXPRESSION PROGRAMS. OUR PREVIOUS STUDIES SHOWED THAT CHRONIC MORPHINE-INDUCED DECREASE OF MIR-105 IN THE MEDIAL PREFRONTAL CORTEX (MPFC) CONTRIBUTED TO CONTEXT-INDUCED RETRIEVAL OF MORPHINE WITHDRAWAL MEMORY. HOWEVER, HOW CHRONIC MORPHINE TREATMENT DECREASES MIR-105 IN THE MPFC STILL REMAINS UNKNOWN. THE PRESENT STUDY SHOWS THAT CHRONIC MORPHINE INDUCES ADDICTION-RELATED CHANGE IN MIR-105 IN THE MPFC VIA TWO KINDS OF TRANSCRIPTION FACTORS: THE FIRST TRANSCRIPTION FACTOR IS CREB ACTIVATED BY MU RECEPTORS-ERK-P90RSK SIGNALING PATHWAY AND THE SECOND TRANSCRIPTION FACTOR IS GLUCOCORTICOID RECEPTOR (GR), WHICH AS A NEGATIVE TRANSCRIPTION FACTOR, MEDIATES CHRONIC MORPHINE-INDUCED DECREASE IN MIR-105 IN THE MPFC OF RATS. 2022 20 3122 35 GESTATIONAL VALPROIC ACID EXPOSURE INDUCES EPIGENETIC MODIFICATIONS IN MURINE DECIDUA. INTRODUCTION: VALPROIC ACID (VPA), A WIDELY PRESCRIBED ANTIEPILEPTIC DRUG AND AN EFFECTIVE TREATMENT FOR BIPOLAR DISORDER AND NEUROPATHIC PAIN, RESULTS IN MULTIPLE DEVELOPMENTAL DEFECTS FOLLOWING IN UTERO EXPOSURE. UTERINE DECIDUA PROVIDES NUTRITIONAL AND PHYSICAL SUPPORT DURING IMPLANTATION AND EARLY EMBRYONIC DEVELOPMENT. PERTURBATIONS IN THE MOLECULAR MECHANISMS WITHIN DECIDUAL TISSUE DURING EARLY PREGNANCY MIGHT AFFECT EARLY EMBRYONIC GROWTH, RESULT IN EARLY PREGNANCY LOSS OR CAUSE COMPLICATIONS IN THE LATER GESTATIONAL STAGE. VPA IS A KNOWN HISTONE DEACETYLASE INHIBITOR AND EPIGENETIC CHANGES SUCH AS HISTONE HYPERACETYLATION AND METHYLATION HAVE BEEN PROPOSED AS A MECHANISM OF VPA-INDUCED TERATOGENESIS. METHODS: THIS STUDY INVESTIGATED THE EFFECTS OF IN UTERO VPA EXPOSURE ON HISTONE MODIFICATIONS IN MURINE DECIDUAL TISSUE. PREGNANT CD-1 MICE WERE EXPOSED TO 400 MG/KG VPA OR SALINE ON GD9 VIA SUBCUTANEOUS INJECTION. DECIDUAL TISSUE FROM EACH GESTATIONAL SAC WAS HARVESTED AT 1, 3 AND 6 H FOLLOWING EXPOSURE. LEVELS OF ACETYLATED HISTONES H3, H4 AND H3K56, AS WELL AS METHYLATED HISTONES H3K9 AND H3K27 WERE ACID EXTRACTED AND ASSESSED BY WESTERN BLOTTING FOLLOWED BY ACID HISTONE EXTRACTION. RESULTS: VPA EXPOSURE INDUCED A SIGNIFICANT INCREASE (P < 0.05) IN THE LEVELS OF ACETYLATED H3 AT 1, 3 H; ACETYLATED H4 AT 1, 3 AND 6 H AND TRIMETHYLATED H3K9 AT 6 H. IN CONTRAST, NO SIGNIFICANT PERTURBATIONS WERE NOTED IN THE LEVELS OF MONOMETHYLATED H3K9, TRIMETHYLATED H3K27 AND ACETYLATED H3K56. DISCUSSION: THE RESULTS FROM THIS STUDY SUGGEST THAT VPA-INDUCED DECIDUAL HISTONE MODIFICATIONS MIGHT PLAY AN IMPORTANT ROLE AS A MECHANISM OF VPA-INDUCED TERATOGENESIS DURING EARLY EMBRYONIC GROWTH. 2021