1 1848 177 EFFECTS OF VENLAFAXINE ON THE EXPRESSION LEVEL AND METHYLATION STATUS OF GENES INVOLVED IN OXIDATIVE STRESS IN RATS EXPOSED TO A CHRONIC MILD STRESS. RECENT HUMAN AND ANIMAL STUDIES INDICATE THAT OXIDATIVE AND NITROSATIVE STRESS MAY PLAY A ROLE IN THE AETIOLOGY AND PATHOGENESIS OF DEPRESSION. THIS STUDY INVESTIGATES THE EFFECT OF CHRONIC ADMINISTRATION OF THE SEROTONIN-NOREPINEPHRINE REUPTAKE INHIBITOR, VENLAFAXINE, ON THE EXPRESSION AND METHYLATION STATUS OF SOD1, SOD2, GPX1, GPX4, CAT, NOS1 AND NOS2 IN THE BRAIN AND BLOOD OF RATS EXPOSED TO A CHRONIC MILD STRESS (CMS) MODEL OF DEPRESSION. SEPARATE GROUPS OF ANIMALS WERE EXPOSED TO CMS FOR 2 OR 7 WEEKS; THE SECOND GROUP RECEIVED SALINE OR VENLAFAXINE (10 MG/KG/D, IP) FOR 5 WEEKS. AFTER COMPLETION OF BOTH STRESS CONDITIONS AND DRUG ADMINISTRATION, THE MRNA AND PROTEIN EXPRESSION OF SELECTED GENES AND THE METHYLATION STATUS OF THEIR PROMOTERS WERE MEASURED IN PERIPHERAL MONONUCLEAR BLOOD CELLS (PBMCS) AND IN BRAIN STRUCTURES (HIPPOCAMPUS, AMYGDALA, HYPOTHALAMUS, MIDBRAIN, CORTEX, BASAL GANGLIA) WITH THE USE OF TAQMAN GENE EXPRESSION ASSAY, WESTERN BLOT AND METHYLATION-SENSITIVE HIGH-RESOLUTION MELTING TECHNIQUES. CMS CAUSED A DECREASE IN SUCROSE CONSUMPTION, AND THIS EFFECT WAS NORMALIZED BY FLUOXETINE. IN PBMCS, SOD1, SOD2 AND NOS2 MRNA EXPRESSION CHANGED ONLY AFTER VENLAFAXINE ADMINISTRATION. IN BRAIN, CAT, GPX1, GPX4 AND NOS1 GENE EXPRESSION CHANGED FOLLOWING CMS OR VENLAFAXINE EXPOSURE, MOST PROMINENTLY IN THE HIPPOCAMPUS, MIDBRAIN AND BASAL GANGLIA. CMS INCREASED THE METHYLATION OF THE GPX1 PROMOTER IN PBMCS, THE SECOND GPX4 PROMOTER IN MIDBRAIN AND BASAL GANGLIA, AND SOD1 AND SOD2 IN HIPPOCAMPUS. THE CMS ANIMALS TREATED WITH VENLAFAXINE DISPLAYED A SIGNIFICANTLY HIGHER CAT LEVEL IN MIDBRAIN AND CEREBRAL CORTEX. CMS CAUSED AN ELEVATION OF GPX4 IN THE HIPPOCAMPUS, WHICH WAS LOWERED IN CEREBRAL CORTEX BY VENLAFAXINE. THE RESULTS INDICATE THAT CMS AND VENLAFAXINE ADMINISTRATION AFFECT THE METHYLATION OF PROMOTERS OF GENES INVOLVED IN OXIDATIVE AND NITROSATIVE STRESS. THEY ALSO INDICATE THAT PERIPHERAL AND CENTRAL TISSUE DIFFER IN THEIR RESPONSE TO STRESS OR ANTIDEPRESSANT TREATMENTS. IT IS POSSIBLE THAT THAT APART FROM DNA METHYLATION, A CRUCIAL ROLE OF EXPRESSION LEVEL OF GENES MAY BE PLAYED BY OTHER FORMS OF EPIGENETIC REGULATION, SUCH AS HISTONE MODIFICATION OR MICRORNA INTERFERENCE. THESE FINDINGS PROVIDE STRONG EVIDENCE FOR THESIS THAT ANALYSIS OF THE LEVEL OF MRNA AND PROTEIN EXPRESSION AS WELL AS THE STATUS OF PROMOTER METHYLATION CAN HELP IN UNDERSTANDING THE PATHOMECHANISMS OF MENTAL DISEASES, INCLUDING DEPRESSION, AND THE MECHANISMS OF ACTION OF DRUGS EFFECTIVE IN THEIR THERAPY. 2020 2 4275 34 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 3 1818 39 EFFECTS OF CHRONIC METHAMPHETAMINE EXPOSURE ON REWARDING BEHAVIOR AND NEURODEGENERATION MARKERS IN ADULT MICE. RECREATIONAL AND MEDICAL USE OF STIMULANTS AMONG YOUNG ADULTS HAVE GAINED POPULARITY IN THE UNITED STATES OVER THE LAST DECADE AND THEIR USE MAY INCREASE VULNERABILITY TO BRAIN BIOCHEMICAL CHANGES AND ADDICTIVE BEHAVIORS. THE LONG-TERM EFFECTS OF CHRONIC STIMULANT EXPOSURE IN LATER ADULTHOOD HAVE NOT BEEN FULLY ELUCIDATED.OUR STUDY INVESTIGATED WHETHER CHRONIC EXPOSURE TO METHAMPHETAMINE (METH), AT A DOSE DESIGNED TO EMULATE HUMAN THERAPEUTIC DOSING FOR ADHD, WOULD PROMOTE BIOCHEMICAL ALTERATIONS AND AFFECT SENSITIVITY TO THE REWARDING EFFECTS OF SUBSEQUENT METH DOSING.GROUPS OF 3.5-MONTH-OLD MALE AND FEMALE C57BL/6J MICE WERE ADMINISTERED NON-CONTINGENT INTRAPERITONEAL INJECTIONS OF EITHER SALINE OR METH (1.4 MG/KG) TWICE A DAY FOR 1 MONTH (5 DAYS/WEEK). METH (0.5 MG/KG)-INDUCED CONDITIONED PLACE PREFERENCE (CPP) WAS TESTED IN MICE TO DETERMINE THE EFFECTS OF PREVIOUS METH EXPOSURE ON REWARD-RELATED BEHAVIOR. MICE WERE RANDOMLY ASSIGNED TO EXPERIMENT I (MALES AND FEMALES) OR EXPERIMENT II (FEMALES ONLY) IN WHICH CPP TESTING WAS RESPECTIVELY PERFORMED EITHER 0.5 OR 5 MONTHS AFTER THE END OF METH INJECTIONS, AT ~5 OR 10 MONTHS OLD RESPECTIVELY. THE MIDBRAIN AND STRIATUM, REGIONS INVOLVED IN REWARD CIRCUIT, WERE ASSESSED FOR MARKERS ASSOCIATED WITH NEUROTOXICITY, DOPAMINERGIC FUNCTION, NEUROINFLAMMATION AND EPIGENETIC CHANGES AFTER BEHAVIORAL TESTING.PREVIOUS EXPOSURE TO CHRONIC METH DID NOT HAVE SIGNIFICANT SHORT-TERM EFFECTS ON CPP RESPONSE BUT LED TO A DECREASED CPP RESPONSE IN 10-MONTH-OLD FEMALES. PREVIOUS EXPOSURE TO METH INDUCED SOME SHORT-TERM CHANGES TO BIOCHEMICAL MARKERS MEASURED IN A BRAIN REGION AND SEX-DEPENDENT MANNER, WHILE LONG-TERM CHANGES WERE ONLY OBSERVED WITH GFAP AND KDM5C.IN CONCLUSION, OUR DATA SUGGEST SEX- AND POST-EXPOSURE DURATION-DEPENDENT OUTCOMES AND WARRANT FURTHER EXPLORATION OF THE LONG-TERM NEUROBEHAVIORAL CONSEQUENCES OF PSYCHOSTIMULANT USE IN BOTH SEXES. 2023 4 6582 44 TRICHOSTATIN A, A HISTONE DEACETYLASE INHIBITOR, ALLEVIATES THE EMOTIONAL ABNORMALITY INDUCED BY MALADAPTATION TO STRESS IN MICE. RECENT REPORTS HAVE IMPLIED THAT ABERRANT BIOCHEMICAL PROCESSES IN THE BRAIN ARE FREQUENTLY ACCOMPANIED BY SUBTLE SHIFTS IN THE CELLULAR EPIGENETIC PROFILE THAT MIGHT UNDERLIE THE PATHOGENIC PROGRESSION OF PSYCHIATRIC DISORDERS. THE AIM OF THE PRESENT STUDY WAS TO EXAMINE THE EFFECT OF TRICHOSTATIN A (TSA), A HISTONE DEACETYLASE (HDAC) INHIBITOR, ON THE EMOTIONAL ABNORMALITY INDUCED BY MALADAPTATION TO STRESS IN MICE. MICE WERE EXPOSED TO REPEATED RESTRAINT STRESS FOR 240 MIN/DAY FOR 14 DAYS. WE APPLIED DOSING SCHEDULES. IN ONE SCHEDULE, FROM THE 3RD DAY OF STRESS EXPOSURE, MICE WERE TREATED WITH TSA (1650 MUM/4 MUL, I.C.V.) IMMEDIATELY AFTER THE DAILY EXPOSURE TO RESTRAINT STRESS. IN THE OTHER SCHEDULE, FROM THE 1ST DAY OF STRESS EXPOSURE, MICE WERE TREATED WITH TSA 2 H BEFORE EXPOSURE TO RESTRAINT STRESS. AFTER THE FINAL EXPOSURE TO RESTRAINT STRESS, THE EMOTIONALITY OF MICE WAS EVALUATED USING THE HOLE-BOARD TEST. MICE THAT WERE EXPOSED TO RESTRAINT STRESS FOR 240 MIN/DAY FOR 14 DAYS SHOWED A DECREASE IN HEAD-DIPPING BEHAVIOR. THIS DECREASED EMOTIONALITY OBSERVED IN STRESS-MALADAPTIVE MICE WAS SIGNIFICANTLY RECOVERED BY CHRONIC TREATMENT WITH TSA 2 H BEFORE DAILY EXPOSURE TO RESTRAINT STRESS, WHICH CONFIRMED THE DEVELOPMENT OF STRESS ADAPTATION. ON THE OTHER HAND, NO SUCH STRESS ADAPTATION WAS OBSERVED UNDER CHRONIC TREATMENT WITH TSA IMMEDIATELY AFTER DAILY STRESS EXPOSURE. A BIOCHEMICAL STUDY SHOWED THAT TRYPTOPHAN HYDROXYLASE, THE RATE-LIMITING ENZYME IN SEROTONIN (5-HT) SYNTHESIS, WAS INCREASED IN MIDBRAIN CONTAINING RAPHE NUCLEI OBTAINED FROM STRESS-ADAPTED MICE THAT WERE CHRONICALLY TREATED WITH TSA 2 H BEFORE DAILY STRESS EXPOSURE. THESE FINDINGS SUGGEST THAT AN HDAC INHIBITOR MAY HAVE A BENEFICIAL EFFECT ON STRESS ADAPTATION BY AFFECTING 5-HT NEURAL FUNCTION IN THE BRAIN AND ALLEVIATE THE EMOTIONAL ABNORMALITY UNDER CONDITIONS OF EXCESSIVE STRESS. 2022 5 4498 46 MORPHINE REGULATES ARGONAUTE 2 AND TH EXPRESSION AND ACTIVITY BUT NOT MIR-133B IN MIDBRAIN DOPAMINERGIC NEURONS. EPIGENETIC CHANGES SUCH AS MICRORNAS (MIRS)/AGO2-INDUCED GENE SILENCING REPRESENT COMPLEX MOLECULAR SIGNATURE THAT REGULATE CELLULAR PLASTICITY. RECENT STUDIES SHOWED INVOLVEMENT OF MIRS AND AGO2 IN DRUG ADDICTION. IN THIS STUDY, WE SHOW THAT CHANGES IN GENE EXPRESSION INDUCED BY MORPHINE AND MORPHINE WITHDRAWAL OCCUR WITH CONCOMITANT EPIGENETIC MODIFICATIONS IN THE MESOLIMBIC DOPAMINERGIC (DA) PATHWAY [VENTRAL TEGMENTAL AREA (VTA)/NUCLEUS ACCUMBENS (NAC) SHELL], WHICH IS CRITICALLY INVOLVED IN DRUG-INDUCED DEPENDENCE. WE FOUND THAT ACUTE OR CHRONIC MORPHINE ADMINISTRATION AS WELL AS MORPHINE WITHDRAWAL DID NOT MODIFY MIR-133B MESSENGER RNA (MRNA) EXPRESSION IN THE VTA, WHEREAS AGO2 PROTEIN LEVELS WERE DECREASED AND INCREASED IN MORPHINE-DEPENDENT RATS AND AFTER MORPHINE WITHDRAWAL, RESPECTIVELY. THESE CHANGES WERE PARALLELED WITH ENHANCED AND DECREASED NAC TYROSINE HYDROXYLASE (TH) PROTEIN (AN EARLY DA MARKER) IN MORPHINE-DEPENDENT RATS AND AFTER WITHDRAWAL, RESPECTIVELY. WE ALSO OBSERVED CHANGES IN TH MRNA EXPRESSION IN THE VTA THAT COULD BE RELATED TO AGO2-INDUCED TRANSLATIONAL REPRESSION OF TH MRNA DURING MORPHINE WITHDRAWAL. HOWEVER, THE VTA NUMBER OF TH-POSITIVE NEURONS SUFFERED NO ALTERATIONS AFTER THE DIFFERENT TREATMENT. ACUTE MORPHINE ADMINISTRATION PRODUCED A MARKED INCREASE IN TH ACTIVITY AND DA TURNOVER IN THE NAC (SHELL). IN CONTRAST, PRECIPITATED MORPHINE WITHDRAWAL DECREASED TH ACTIVATION AND DID NOT CHANGE DA TURNOVER. THESE FINDINGS PROVIDE NEW INFORMATION INTO THE POSSIBLE CORRELATION BETWEEN AGO2/MIRS COMPLEX REGULATION AND DA NEURONS PLASTICITY DURING OPIATE ADDICTION. 2015 6 3331 43 HISTONE DEACETYLASE INHIBITOR SUBERANILOHYDROXAMIC ACID TREATMENT REVERSES HYPOSENSITIVITY TO GAMMA-AMINOBUTYRIC ACID IN THE VENTRAL TEGMENTAL AREA DURING ETHANOL WITHDRAWAL. BACKGROUND: THE VENTRAL TEGMENTAL AREA (VTA) IS IMPORTANT FOR ALCOHOL-RELATED REWARD AND REINFORCEMENT. MOUSE VTA NEURONS ARE HYPOSENSITIVE TO GAMMA-AMINOBUTYRIC ACID (GABA) DURING ETHANOL (ETOH) WITHDRAWAL, AND GABA RESPONSIVENESS IS NORMALIZED BY IN VITRO TREATMENT WITH HISTONE DEACETYLASE INHIBITORS (HDACI). THE PRESENT STUDY EXAMINED THE EFFECT OF A SYSTEMICALLY ADMINISTERED HDACI, SUBERANILOHYDROXAMIC ACID (SAHA) ON GABA SENSITIVITY, AND RELATED MOLECULAR CHANGES IN VTA NEURONS DURING WITHDRAWAL AFTER CHRONIC ETOH INTAKE IN RATS. METHODS: SPRAGUE DAWLEY MALE ADULT RATS WERE FED WITH LIEBER-DECARLI DIET (9% ETOH OR CONTROL DIET) FOR 16 DAYS. EXPERIMENTAL GROUPS INCLUDED CONTROL DIET-FED AND ETOH DIET-FED (0- OR 24-HOUR WITHDRAWAL) RATS TREATED WITH EITHER SAHA OR VEHICLE INJECTION. SINGLE-UNIT RECORDINGS WERE USED TO MEASURE THE RESPONSE OF VTA NEURONS TO GABA. IMMUNOHISTOCHEMISTRY WAS PERFORMED TO EXAMINE LEVELS OF HDAC2, ACETYLATED HISTONE H3 LYSINE 9 (ACH3K9), AND GABA(A) RECEPTOR ALPHA1 AND ALPHA5 SUBUNITS IN THE VTA; QUANTITATIVE POLYMERASE CHAIN REACTION WAS PERFORMED TO EXAMINE THE MRNA LEVELS OF HDAC2 AND GABA(A) RECEPTOR SUBUNITS. RESULTS: VTA NEURONS FROM THE WITHDRAWAL GROUP EXHIBITED GABA HYPOSENSITIVITY. IN VIVO SAHA TREATMENT 2 HOURS BEFORE SACRIFICE NORMALIZED THE SENSITIVITY OF VTA NEURONS TO GABA. ETOH WITHDRAWAL WAS ASSOCIATED WITH INCREASED HDAC2 AND DECREASED ACH3K9 PROTEIN LEVELS; SAHA TREATMENT NORMALIZED ACH3K9 LEVELS. INTERESTINGLY, NO SIGNIFICANT CHANGE WAS OBSERVED IN THE MRNA LEVELS OF HDAC2. THE MRNA LEVELS, BUT NOT PROTEIN LEVELS, OF GABA(A) RECEPTOR ALPHA1 AND ALPHA5 SUBUNITS WERE INCREASED DURING WITHDRAWAL. CONCLUSIONS: WITHDRAWAL FROM CHRONIC ETOH EXPOSURE RESULTS IN A DECREASE IN GABA-MEDIATED INHIBITION, AND THIS GABA HYPOSENSITIVITY IS NORMALIZED BY IN VIVO SAHA TREATMENT. DISRUPTION OF SIGNALING IN THE VTA PRODUCED BY ALTERATION OF GABA NEUROTRANSMISSION COULD BE 1 NEUROADAPTIVE PHYSIOLOGICAL PROCESS LEADING TO CRAVING AND RELAPSE. THESE RESULTS SUGGEST THAT HDACI PHARMACOTHERAPY WITH AGENTS LIKE SAHA MIGHT BE AN EFFECTIVE TREATMENT FOR ALCOHOLISM. 2018 7 6082 44 THE EFFECT OF MORPHINE UPON DNA METHYLATION IN TEN REGIONS OF THE RAT BRAIN. MORPHINE IS ONE OF THE MOST EFFECTIVE ANALGESICS IN MEDICINE. HOWEVER, ITS USE IS ASSOCIATED WITH THE DEVELOPMENT OF TOLERANCE AND DEPENDENCE. RECENT STUDIES DEMONSTRATING EPIGENETIC CHANGES IN THE BRAIN AFTER EXPOSURE TO OPIATES HAVE PROVIDED INSIGHT INTO MECHANISMS POSSIBLY UNDERLYING ADDICTION. IN THIS STUDY, WE SOUGHT TO IDENTIFY EPIGENETIC CHANGES IN TEN REGIONS OF THE RAT BRAIN FOLLOWING ACUTE AND CHRONIC MORPHINE EXPOSURE. WE ANALYZED DNA METHYLATION OF SIX NUCLEAR-ENCODED GENES IMPLICATED IN BRAIN FUNCTION (BDNF, COMT, IL1B, IL6, NR3C1, AND TNF) AND THREE MITOCHONDRIALLY-ENCODED GENES (MTCO1, MTCO2, AND MTCO3), AND MEASURED GLOBAL 5-METHYLCYTOSINE (5MC) AND 5-HYDROXYMETHYLCYTOSINE (5 HMC) LEVELS. WE OBSERVED DIFFERENTIAL METHYLATION OF BDNF AND IL6 IN THE PONS, NR3C1 IN THE CEREBELLUM, AND IL1B IN THE HIPPOCAMPUS IN RESPONSE TO ACUTE MORPHINE EXPOSURE (ALL P VALUE < 0.05). CHRONIC EXPOSURE WAS ASSOCIATED WITH DIFFERENTIAL METHYLATION OF BDNF AND COMT IN THE PONS, NR3C1 IN THE HIPPOCAMPUS AND IL1B IN THE MEDULLA OBLONGATA (ALL P VALUE < 0.05). GLOBAL 5MC LEVELS SIGNIFICANTLY DECREASED IN THE SUPERIOR COLLICULUS FOLLOWING BOTH ACUTE AND CHRONIC MORPHINE EXPOSURE, AND INCREASED IN THE HYPOTHALAMUS FOLLOWING CHRONIC EXPOSURE. CHRONIC EXPOSURE WAS ALSO ASSOCIATED WITH SIGNIFICANTLY INCREASED GLOBAL 5HMC LEVELS IN THE CEREBRAL CORTEX, HIPPOCAMPUS, AND HYPOTHALAMUS, BUT SIGNIFICANTLY DECREASED IN THE MIDBRAIN. OUR RESULTS DEMONSTRATE, FOR THE FIRST TIME, HIGHLY LOCALIZED EPIGENETIC CHANGES IN THE RAT BRAIN FOLLOWING ACUTE AND CHRONIC MORPHINE EXPOSURE. FURTHER WORK IS REQUIRED TO ELUCIDATE THE POTENTIAL ROLE OF THESE CHANGES IN THE FORMATION OF TOLERANCE AND DEPENDENCE. 2017 8 2750 41 EXPRESSION LEVELS OF THE TYROSINE HYDROXYLASE GENE AND HISTONE MODIFICATIONS AROUND ITS PROMOTER IN THE LOCUS COERULEUS AND VENTRAL TEGMENTAL AREA OF RATS DURING FORCED ABSTINENCE FROM MORPHINE. BACKGROUND: EPIGENETIC MECHANISMS SUCH AS HISTONE MODIFICATIONS MAY BE INVOLVED IN THE STRUCTURAL AND BEHAVIORAL CHANGES ASSOCIATED WITH ADDICTION. WE STUDIED WHETHER MORPHINE-INDUCED CHANGES IN MRNA LEVELS OF THE CATECHOLAMINE BIOSYNTHESIS ENZYME, TYROSINE HYDROXYLASE (TH), ARE ASSOCIATED WITH HISTONE MODIFICATIONS AROUND THE PROMOTER OF THIS GENE IN THE LOCUS COERULEUS (LC) AND VENTRAL TEGMENTAL AREA (VTA) OF RATS. METHODS: DEPENDENCE WAS INDUCED IN RATS BY INTRAPERITONEAL INJECTIONS OF MORPHINE FOR 11 DAYS. THE ANIMALS WERE KILLED 2 H (CHRONIC MORPHINE), 24 H AND 7 DAYS (SPONTANEOUS WITHDRAWAL) AFTER THE LAST INJECTION OF MORPHINE. RESULTS: ANALYSIS OF OUR REAL-TIME QUANTITATIVE REVERSE TRANSCRIPTION PCR RESULTS BY 1-WAY ANOVA SHOWED SIGNIFICANT UPREGULATION (5.13 +/- 0.39 FOLDS) OF LC LEVELS OF THE TH TRANSCRIPT 24 H AFTER THE LAST INJECTION OF MORPHINE TO RATS, WHEN COMPARED WITH 2 H AND 7 DAYS TIME POINTS. CHRONIC MORPHINE AND MORPHINE ABSTINENCE FAILED TO CAUSE ANY SIGNIFICANT CHANGES IN THE LEVELS OF TH MRNA IN THE VTA AFTER CESSATION OF MORPHINE. CONSISTENTLY, CHROMATIN IMMUNOPRECIPITATION REAL-TIME QUANTITATIVE PCR ASSAYS REVEALED THAT 24 H AFTER THE LAST INJECTION OF MORPHINE, LEVELS OF H3 ACETYLATION WERE SIGNIFICANTLY INCREASED (4.12 +/- 0.38 FOLDS) AT THE PROMOTER OF THE TH GENE IN THE LC BUT NOT IN THE VTA. OUR DATA ALSO SHOWED THAT HISTONE H3 TRIMETHYLATION FAILED TO CHANGE AROUND THE TH GENE PROMOTER EITHER IN THE VTA OR IN THE LC AFTER MORPHINE ABSTINENCE. CONCLUSIONS: RESULTS OF THE PRESENT STUDY, FOR THE FIRST TIME, DEMONSTRATE THE INVOLVEMENT OF HISTONE H3 ACETYLATION IN THE REGULATION OF TH GENE EXPRESSION IN THE LC OF RATS DURING FORCED ABSTINENCE FROM MORPHINE. 2018 9 1003 40 CHRONIC TREATMENT WITH FLUOXETINE INDUCES SEX-DEPENDENT ANALGESIC EFFECTS AND MODULATES HDAC2 AND MGLU2 EXPRESSION IN FEMALE MICE. GENDER AND SEX DIFFERENCES IN PAIN RECOGNITION AND DRUG RESPONSES HAVE BEEN REPORTED IN CLINICAL TRIALS AND EXPERIMENTAL MODELS OF PAIN. AMONG ANTIDEPRESSANTS, CONTRADICTORY RESULTS HAVE BEEN OBSERVED IN PATIENTS TREATED WITH SELECTIVE SEROTONIN REUPTAKE INHIBITORS (SSRIS). THIS STUDY EVALUATED SEX DIFFERENCES IN RESPONSE TO THE SSRI FLUOXETINE AFTER CHRONIC ADMINISTRATION IN THE MOUSE FORMALIN TEST. ADULT MALE AND FEMALE CD1 MICE WERE INTRAPERITONEALLY INJECTED WITH FLUOXETINE (10 MG/KG) FOR 21 DAYS AND SUBJECTED TO PAIN ASSESSMENT. FLUOXETINE TREATMENT REDUCED THE SECOND PHASE OF THE FORMALIN TEST ONLY IN FEMALE MICE WITHOUT PRODUCING BEHAVIORAL CHANGES IN MALES. WE ALSO OBSERVED THAT FLUOXETINE WAS ABLE TO SPECIFICALLY INCREASE THE EXPRESSION OF METABOTROPIC GLUTAMATE RECEPTOR TYPE-2 (MGLU2) IN FEMALES. ALSO A REDUCED EXPRESSION OF THE EPIGENETIC MODIFYING ENZYME, HISTONE DEACETYLASE 2 (HDAC2), IN DORSAL ROOT GANGLIA (DRG) AND DORSAL HORN (DH) TOGETHER WITH AN INCREASE HISTONE 3 ACETYLATION (H3) LEVEL WAS OBSERVED IN FEMALES BUT NOT IN MALES. WITH THIS STUDY WE PROVIDE EVIDENCE THAT FLUOXETINE INDUCES SEX SPECIFIC CHANGES IN HDAC2 AND MGLU2 EXPRESSION IN THE DH OF THE SPINAL CORD AND IN DRGS AND SUGGESTS A MOLECULAR EXPLANATION FOR THE ANALGESIC EFFECTS IN FEMALE MICE. 2017 10 2827 44 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 11 5651 40 SEX DIFFERENCES IN THE EPIGENETIC REGULATION OF CHRONIC VISCERAL PAIN FOLLOWING UNPREDICTABLE EARLY LIFE STRESS. BACKGROUND: WE PREVIOUSLY REPORTED THAT EARLY LIFE STRESS (ELS) DYSREGULATED GLUCOCORTICOID RECEPTOR (GR) AND CORTICOTROPHIN-RELEASING HORMONE (CRH) EXPRESSION IN THE CENTRAL NUCLEUS OF THE AMYGDALA (CEA). EPIGENETIC MODIFICATIONS SERVE AS MEMORIES OF ADVERSE EVENTS THAT OCCURRED DURING EARLY LIFE. THEREFORE, WE HYPOTHESIZED THAT EPIGENETIC MECHANISMS ALTER GR AND CRH EXPRESSION IN THE CEA AND UNDERLIE CHRONIC VISCERAL PAIN AFTER ELS. METHODS: NEONATAL RATS WERE EXPOSED TO UNPREDICTABLE, PREDICTABLE ELS, OR ODOR ONLY (NO STRESS CONTROL) FROM POSTNATAL DAYS 8 TO 12. IN ADULTHOOD, VISCERAL SENSITIVITY WAS ASSESSED OR THE CEA WAS ISOLATED FOR WESTERN BLOT OR CHIP-QPCR TO STUDY HISTONE MODIFICATIONS AT THE GR AND CRH PROMOTERS. FEMALE ADULT RATS UNDERWENT STEREOTAXIC IMPLANTATION OF INDWELLING CANNULAS FOR MICROINJECTIONS OF GARCINOL (HAT INHIBITOR) INTO THE CEA. AFTER 7 DAYS OF MICROINJECTIONS, VISCERAL SENSITIVITY WAS ASSESSED OR THE CEA WAS ISOLATED FOR CHIP-QPCR ASSAYS. RESULTS: UNPREDICTABLE ELS INCREASED VISCERAL SENSITIVITY IN ADULT FEMALE RATS, BUT NOT IN MALE COUNTERPARTS. ELS INCREASED HISTONE 3 LYSINE 9 (H3K9) ACETYLATION IN THE CEA AND H3K9 ACETYLATION LEVELS AT THE GR PROMOTER IN THE CEA OF ADULT FEMALE RATS. AFTER UNPREDICTABLE ELS, H3K9 ACETYLATION WAS INCREASED AND GR BINDING WAS DECREASED AT THE CRH PROMOTER. ADMINISTRATION OF GARCINOL IN THE CEA OF ADULT FEMALES, THAT UNDERWENT UNPREDICTABLE ELS, NORMALIZED H3K9 ACETYLATION AND RESTORED GR BINDING AT THE CRH PROMOTER. CONCLUSION: DYSREGULATED HISTONE ACETYLATION AND GR BINDING AT THE CRH PROMOTER IN THE CEA ARE AN IMPORTANT MECHANISM FOR "MEMORIZING" ELS EVENTS MEDIATING VISCERAL PAIN IN ADULTHOOD. 2020 12 6612 37 ULTRA-LOW-DOSE NALOXONE ENHANCES THE ANTINOCICEPTIVE EFFECT OF MORPHINE IN PTX-TREATED RATS: REGULATION ON GLOBAL HISTONE METHYLATION. OBJECTIVE: EPIGENETIC REPROGRAMMING MAY HAVE A POSSIBLE ROLE IN NEUROPATHIC PAIN DEVELOPMENT; THE PRESENT STUDY EXAMINED THE GLOBAL PATTERNS OF LYSINE HISTONE MODIFICATION. IN THIS SERIAL STUDY WE ANALYZED THE LEVELS OF HISTONE 3 LYSINE 4 MONOMETHYLATION, HISTONE 3 LYSINE 4 DIMETHYLATION, AND HISTONE 3 LYSINE 9 TRIMETHYLATION IN PERTUSSIS TOXIN (PTX)-INDUCED THERMAL HYPERALGESIC RAT SPINAL CORDS. METHODS: MALE WISTAR RATS IMPLANTED WITH AN INTRATHECAL CATHETER RECEIVED A SINGLE INTRATHECAL PTX (1 MUG IN 5 MUL SALINE) INJECTION. FOUR DAYS LATER, THEY WERE RANDOMLY ASSIGNED TO RECEIVE EITHER A SINGLE INJECTION OF SALINE, OR ULTRA-LOW-DOSE NALOXONE (15 NG IN 5 MUL SALINE), FOLLOWED BY MORPHINE (10 MUG IN 5 MUL SALINE) INJECTION 30 MINUTES LATER. RESULTS: THE RESULTS SHOWED THAT PTX INJECTION INDUCED THERMAL HYPERALGESIA AND SIGNIFICANT INCREASE OF GLOBAL HISTONE METHYLATION IN THE SPINAL CORDS. INTRATHECAL MORPHINE ALONE DID NOT AFFECT THE THERMAL HYPERALGESIA AND GLOBAL HISTONE METHYLATION. IN CONTRAST, INTRATHECAL ADMINISTRATION OF ULTRA-LOW-DOSE NALOXONE PLUS MORPHINE SIGNIFICANTLY ATTENUATED THE PTX-INDUCED THERMAL HYPERALGESIA AND DOWN-REGULATED THE GLOBAL HISTONE METHYLATION. CONCLUSION: THE RESULTS SUGGEST THAT ULTRA-LOW-DOSE NALOXONE MIGHT BE CLINICAL VALUABLE FOR NEUROPATHIC PAIN MANAGEMENT VIA REGULATING GLOBAL HISTONE MODIFICATION. 2012 13 69 37 A MEDIAL PREFRONTAL CORTEX-NUCLEUS ACUMENS CORTICOTROPIN-RELEASING FACTOR CIRCUITRY FOR NEUROPATHIC PAIN-INCREASED SUSCEPTIBILITY TO OPIOID REWARD. RECENT STUDIES HAVE SHOWN THAT PERSISTENT PAIN FACILITATES THE RESPONSE TO MORPHINE REWARD. HOWEVER, THE CIRCUIT MECHANISM UNDERLYING THIS PROCESS REMAINS AMBIGUOUS. IN THIS STUDY, USING CHRONIC CONSTRICTION INJURY (CCI) OF THE SCIATIC NERVE IN MICE, WE FOUND THAT PERSISTENT NEUROPATHIC PAIN REDUCED THE MINIMUM NUMBER OF MORPHINE CONDITIONING SESSIONS REQUIRED TO INDUCE CONDITIONED PLACE PREFERENCE (CPP) BEHAVIOR. THIS DOSE OF MORPHINE HAD NO EFFECT ON THE PAIN THRESHOLD. IN THE MEDIAL PREFRONTAL CORTEX (MPFC), WHICH IS INVOLVED IN BOTH PAIN AND EMOTION PROCESSING, CORTICOTROPIN-RELEASING FACTOR (CRF) EXPRESSING NEURONAL ACTIVITY WAS INCREASED IN CCI MICE. CHEMOGENETIC INHIBITION OF MPFC CRF NEURONS REVERSED CCI-INDUCED MORPHINE CPP FACILITATION. FURTHERMORE, THE NUCLEUS ACUMENS (NAC) RECEIVED MPFC CRF FUNCTIONAL PROJECTIONS THAT EXERTED EXCITATORY EFFECTS ON NAC NEURONS. OPTOGENETIC INHIBITION OF MPCF NEURONAL TERMINALS OR LOCAL INFUSION OF THE CRF RECEPTOR 1 (CRFR1) ANTAGONIST IN THE NAC RESTORED THE EFFECTS OF NEUROPATHIC PAIN ON MORPHINE-INDUCED CPP BEHAVIOR, BUT NOT IN NORMAL MICE. ON A MOLECULAR LEVEL, IN CCI MICE, CRFR1 PROTEIN EXPRESSION WAS INCREASED IN THE NAC BY A HISTONE DIMETHYLTRANSFERASE G9A-MEDIATED EPIGENETIC MECHANISM. LOCAL G9A KNOCKDOWN INCREASED THE EXPRESSION OF CRFR1 AND MIMICKED CCI-INDUCED HYPERSENSITIVITY TO ACQUIRING MORPHINE CPP. TAKEN TOGETHER, THESE FINDINGS DEMONSTRATE A PREVIOUSLY UNKNOWN AND SPECIFIC MPFC CRF ENGAGEMENT OF NAC NEURONAL CIRCUITS, THE SENSITIZATION OF WHICH FACILITATES BEHAVIORAL RESPONSES TO MORPHINE REWARD IN NEUROPATHIC PAIN STATES VIA CRFR1S. 2018 14 6108 50 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 15 1320 45 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 16 3177 45 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 17 803 36 CENTRAL CONTROL OF VISCERAL PAIN AND URINARY TRACT FUNCTION. AFFERENT INPUT FROM ADELTA AND C-FIBRES INNERVATING THE URINARY BLADDER ARE PROCESSED DIFFERENTLY BY THE BRAIN, AND HAVE DIFFERENT ROLES IN SIGNALING BLADDER SENSATION. ADELTA FIBRES THAT SIGNAL BLADDER FILLING ACTIVATE A SPINO-BULBO-SPINAL LOOP, WHICH RELAYS IN THE MIDBRAIN PERIAQUEDUCTAL GREY (PAG) AND PONTINE MICTURITION CENTRE (PMC). THE EXCITABILITY OF THIS CIRCUITRY IS REGULATED BY TONIC GABAERGIC INHIBITORY PROCESSES. IN HUMANS AND SOCIALISED ANIMALS MICTURITION IS NORMALLY UNDER VOLITIONAL CONTROL AND INFLUENCED BY A HOST OF PSYCHOSOCIAL FACTORS. HIGHER NERVOUS DECISION-MAKING IN A SOCIAL CONTEXT TO 'GO NOW' OR 'DO NOT GO' PROBABLY RESIDES IN FRONTAL CORTICAL AREAS, WHICH ACT AS A CENTRAL CONTROL SWITCH FOR MICTURITION. EXPOSURE TO PSYCHOSOCIAL STRESS CAN HAVE PROFOUNDLY DISRUPTIVE INFLUENCE ON THE PROCESS AND LEAD TO MALADAPTIVE CHANGES IN THE BLADDER. DURING SLEEPING THE VOIDING REFLEX THRESHOLD APPEARS TO BE RESET TO A HIGHER LEVEL TO PROMOTE URINARY CONTINENCE. UNDER PHYSIOLOGICAL CONDITIONS C-FIBRE BLADDER AFFERENTS ARE NORMALLY SILENT BUT ARE ACTIVATED IN INFLAMMATORY BLADDER STATES AND BY INTENSE DISTENDING PRESSURE. FOLLOWING PROLONGED STIMULATION VISCERAL NOCICEPTORS SENSITISE, LEADING TO A LOWERED THRESHOLD AND HEIGHTENED SENSITIVITY. IN ADDITION, SENSITIZATION MAY OCCUR WITHIN THE CENTRAL PAIN PROCESSING CIRCUITRY, WHICH OUTLASTS THE ORIGINAL NOCICEPTIVE INSULT. VISCERAL NOCICEPTION MAY ALSO BE INFLUENCED BY GENETIC AND ENVIRONMENTAL INFLUENCES. A PERIOD OF CHRONIC STRESS CAN PRODUCE INCREASED SENSITIVITY TO VISCERAL PAIN THAT LASTS FOR MONTHS. ADVERSE EARLY LIFE EVENTS CAN PRODUCE EVEN LONGER LASTING EPIGENETIC CHANGES, WHICH INCREASE THE INDIVIDUAL'S SUSCEPTIBILITY TO DEVELOPING VISCERAL PAIN STATES IN ADULTHOOD. 2016 18 5749 38 SOCIAL DEFEAT INDUCES CHANGES IN HISTONE ACETYLATION AND EXPRESSION OF HISTONE MODIFYING ENZYMES IN THE VENTRAL HIPPOCAMPUS, PREFRONTAL CORTEX, AND DORSAL RAPHE NUCLEUS. CHRONIC EXPOSURE TO STRESS IS ASSOCIATED WITH A NUMBER OF PSYCHIATRIC DISORDERS, BUT LITTLE IS KNOWN ABOUT THE EPIGENETIC MECHANISMS THAT UNDERLIE THE STRESS RESPONSE OR RESILIENCE TO CHRONIC STRESS. WE INVESTIGATED HISTONE ACETYLATION IN SEVEN DIFFERENT BRAIN REGIONS OF RATS EXPOSED TO CHRONIC SOCIAL DEFEAT STRESS: THE DORSAL HIPPOCAMPUS (DHPC), VENTRAL HIPPOCAMPUS (VHPC), MEDIAL PREFRONTAL CORTEX (MPFC), BASOLATERAL AMYGDALA (BLA), LOCUS COERULEUS (LC), PARAVENTRICULAR THALAMUS (PVT), AND DORSAL RAPHE (DR) NUCLEUS. THIS STRESS PARADIGM WAS UNIQUE IN THAT IT ALLOWED RATS TO DISPLAY RESILIENCE IN THE FORM OF AN ACTIVE COPING MECHANISM. WE FOUND THAT THERE WAS AN INCREASE IN ACETYLATION OF H3K9/14 (H3K9/14AC) AND BULK ACETYLATION OF H4K5,8,12,16 (H4K5,8,12,16AC) IN THE DR NUCLEUS OF RATS THAT WERE LESS RESILIENT. LESS RESILIENT RATS ALSO DISPLAYED INCREASED LEVELS OF H3K18 ACETYLATION (H3K18AC) IN THE MPFC WHEN COMPARED TO NON-STRESSED CONTROLS. IN THE VHPC, THERE WAS AN INCREASE IN H3K18AC AND H4K12 (H4K12AC) IN RATS THAT WERE LESS RESILIENT WHEN COMPARED TO NON-STRESSED CONTROL RATS. IN ADDITION, THERE WAS A DECREASE IN LEVELS OF H4K8 ACETYLATION (H4K8AC) IN BOTH RESILIENT AND NON-RESILIENT RATS AS COMPARED TO CONTROLS. WE ASSESSED EXPRESSION OF HISTONE MODIFYING ENZYMES IN THE VHPC AND THE MPFC USING QUANTITATIVE REAL-TIME POLYMERASE CHAIN REACTION (PCR) AND FOUND CHANGES IN EXPRESSION OF A NUMBER OF TARGETS. THESE INCLUDED CHANGES IN SIRT1 AND SIRT2 IN THE VHPC AND CHANGES IN KAT5 IN THE MPFC. OVERALL, THESE RESULTS SUGGEST THAT CHANGES IN HISTONE ACETYLATION AND EXPRESSION OF HISTONE MODIFYING ENZYMES IN THESE REGIONS CORRELATE WITH THE BEHAVIORAL RESPONSE TO STRESS IN SOCIALLY DEFEATED RATS. 2014 19 4397 53 MODULATION OF DNA METHYLATION AND GENE EXPRESSION IN RODENT CORTICAL NEUROPLASTICITY PATHWAYS EXERTS RAPID ANTIDEPRESSANT-LIKE EFFECTS. BACKGROUND: STRESS INCREASES DNA METHYLATION, PRIMARILY A SUPPRESSIVE EPIGENETIC MECHANISM CATALYZED BY DNA METHYLTRANSFERASES (DNMT), AND DECREASES THE EXPRESSION OF GENES INVOLVED IN NEURONAL PLASTICITY AND MOOD REGULATION. DESPITE CHRONIC ANTIDEPRESSANT TREATMENT DECREASES STRESS-INDUCED DNA METHYLATION, IT IS NOT KNOWN WHETHER INHIBITION OF DNMT WOULD CONVEY RAPID ANTIDEPRESSANT-LIKE EFFECTS. AIM: THIS WORK TESTED SUCH A HYPOTHESIS AND EVALUATED WHETHER A BEHAVIORAL EFFECT INDUCED BY DNMT INHIBITORS (DNMTI) CORRESPONDS WITH CHANGES IN DNA METHYLATION AND TRANSCRIPT LEVELS IN GENES CONSISTENTLY ASSOCIATED WITH THE NEUROBIOLOGY OF DEPRESSION AND SYNAPTIC PLASTICITY (BDNF, TRKB, 5-HT(1A), NMDA, AND AMPA). METHODS: MALE WISTAR RATS RECEIVED INTRAPERITONEAL (I.P.) INJECTION OF TWO PHARMACOLOGICALLY DIFFERENT DNMTI (5-AZAD 0.2 AND 0.6 MG/KG OR RG108 0.6 MG/KG) OR VEHICLE (1 ML/KG), 1 H OR 7 DAYS BEFORE THE LEARNED HELPLESSNESS TEST (LH). DNA METHYLATION IN TARGET GENES AND THE CORRESPONDENT TRANSCRIPT LEVELS WERE MEASURED IN THE HIPPOCAMPUS (HPC) AND PREFRONTAL CORTEX (PFC) USING MEDIP-QPCR. IN PARALLEL SEPARATE GROUPS, THE ANTIDEPRESSANT-LIKE EFFECT OF 5-AZAD AND RG108 WAS INVESTIGATED IN THE FORCED SWIMMING TEST (FST). THE INVOLVEMENT OF CORTICAL BDNF-TRKB-MTOR PATHWAYS WAS ASSESSED BY INTRA-VENTRAL MEDIAL PFC (VMPFC) INJECTIONS OF RAPAMYCIN (MTOR INHIBITOR), K252A (TRKB RECEPTOR ANTAGONIST), OR VEHICLE (0.2 MUL/SIDE). RESULTS: WE FOUND THAT BOTH 5-AZAD AND RG108 ACUTELY AND 7 DAYS BEFORE THE TEST DECREASED ESCAPE FAILURES IN THE LH. LH STRESS INCREASED DNA METHYLATION AND DECREASED TRANSCRIPT LEVELS OF BDNF IV AND TRKB IN THE PFC, EFFECTS THAT WERE NOT SIGNIFICANTLY ATTENUATED BY RG108 TREATMENT. THE SYSTEMIC ADMINISTRATION OF 5-AZAD (0.2 MG/KG) AND RG108 (0.2 MG/KG) INDUCED AN ANTIDEPRESSANT-LIKE EFFECT IN FST, WHICH WAS, HOWEVER, ATTENUATED BY TRKB AND MTOR INHIBITION INTO THE VMPFC. CONCLUSION: THESE FINDINGS SUGGEST THAT ACUTE INHIBITION OF STRESS-INDUCED DNA METHYLATION PROMOTES RAPID AND SUSTAINED ANTIDEPRESSANT EFFECTS ASSOCIATED WITH INCREASED BDNF-TRKB-MTOR SIGNALING IN THE PFC. 2021 20 1999 36 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