1 1003 118 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 2 1327 31 DEPRESSION AND ANTIDEPRESSANTS: INSIGHTS FROM KNOCKOUT OF DOPAMINE, SEROTONIN OR NORADRENALINE RE-UPTAKE TRANSPORTERS. MAJOR DEPRESSIVE DISORDER (MDD) WHICH IS SUPPOSED TO RESULT FROM A COMPLEX INTERACTION OF GENETIC AND EPIGENETIC, ENVIRONMENTAL AND DEVELOPMENTAL FACTORS IS ONE OF THE MOST COMMON DEBILITATING PUBLIC HEALTH PROBLEMS. THE MOLECULAR MECHANISMS UNDERLYING THIS DISEASE ARE STILL LARGELY UNCLEAR. IDENTIFYING COMMON PATHWAYS FOR DIVERSE ANTIDEPRESSANTS (ADS) AS WELL AS NEW DRUG TARGETS AND THEREBY DEVELOPING MORE EFFECTIVE TREATMENTS ARE PRIMARY GOALS OF RESEARCH IN THIS FIELD. MAJOR TARGETS OF ADS ARE THE SEROTONIN TRANSPORTER (SERT), THE NORADRENALINE TRANSPORTER (NAT) AND ALSO THE DOPAMINE TRANSPORTER (DAT) LOCATED IN THE PLASMA MEMBRANE OF CORRESPONDING NEURONS. THESE MONOAMINE TRANSPORTERS (MATS) ARE IMPORTANT REGULATORS OF THE EXTRACELLULAR NEUROTRANSMITTER CONCENTRATION. AMONG THE CLINICALLY IMPORTANT ADS ARE TRICYCLIC ADS (E.G. IMIPRAMINE), SELECTIVE SEROTONIN RE-UPTAKE INHIBITORS (SSRIS, E.G. FLUOXETINE), SELECTIVE NORADRENALINE (NA) RE-UPTAKE INHIBITORS (SNRIS, E.G. REBOXETINE) AND NAT/DAT INHIBITORS LIKE BUPROPION. THIS REVIEW IS FOCUSSING ON BRAIN CHANGES IN MONOAMINE NEUROTRANSMITTER SYSTEMS, DOWNSTREAM TARGETS OF MONOAMINERGIC NEUROTRANSMISSION AS WELL AS OF BEHAVIOURS OF MICE WITH A CONVENTIONAL KNOCKOUT (KO) OF EITHER THE SERT, DAT OR NAT. MAT KNOCKOUT INDUCES CHANGES IN BEHAVIOUR AND BRAIN NEUROCHEMISTRY. ALTHOUGH AT LEAST NATKO AND SERTKO MICE WERE EXPECTED TO SHOW A PHENOTYPE LIKE AD-TREATED WILD-TYPE MICE, THIS HOLDS TRUE ONLY FOR THE NATKO MICE WHEREAS SERTKO MICE SHOW AN ANXIETY-LIKE PHENOTYPE. CHRONIC SOCIAL OR RESTRAINT STRESS-INDUCED DEPRESSION-LIKE BEHAVIOUR AND CONCOMITANT CHANGES IN BRAIN NEUROTROPHINS ARE PREVENTED BY PHARMACOLOGICALLY DIVERSE ADS AND BY NATKO. THUS, NATKO MICE ARE AN INTERESTING TOOL TO INVESTIGATE THE MECHANISMS BEYOND MONOAMINES RESPONSIBLE FOR DEPRESSION AS WELL AS FOR AD ACTIONS. 2011 3 881 38 CHRONIC CLOZAPINE TREATMENT RESTRAINS VIA HDAC2 THE PERFORMANCE OF MGLU2 RECEPTOR AGONISM IN A RODENT MODEL OF ANTIPSYCHOTIC ACTIVITY. PRECLINICAL FINDINGS IN RODENT MODELS POINTED TOWARD ACTIVATION OF METABOTROPIC GLUTAMATE 2/3 (MGLU2/3) RECEPTORS AS A NEW PHARMACOLOGICAL APPROACH TO TREAT PSYCHOSIS. HOWEVER, MORE RECENT STUDIES FAILED TO SHOW CLINICAL EFFICACY OF MGLU2/3 RECEPTOR AGONISM IN SCHIZOPHRENIA PATIENTS. WE PREVIOUSLY PROPOSED THAT LONG-TERM ANTIPSYCHOTIC MEDICATION RESTRICTED THE THERAPEUTIC EFFECTS OF THESE GLUTAMATERGIC AGENTS. HOWEVER, LITTLE IS KNOWN ABOUT THE MOLECULAR MECHANISM UNDERLYING THE POTENTIAL REPERCUSSION OF PREVIOUS ANTIPSYCHOTIC EXPOSURE ON THE THERAPEUTIC PERFORMANCE OF MGLU2/3 RECEPTOR AGONISTS. HERE WE SHOW THAT THIS MALADAPTIVE EFFECT OF ANTIPSYCHOTIC TREATMENT IS MEDIATED MOSTLY VIA HISTONE DEACETYLASE 2 (HDAC2). CHRONIC TREATMENT WITH THE ANTIPSYCHOTIC CLOZAPINE LED TO A DECREASE IN MOUSE FRONTAL CORTEX MGLU2 MRNA, AN EFFECT THAT REQUIRED EXPRESSION OF BOTH HDAC2 AND THE SEROTONIN 5-HT(2A) RECEPTOR. THIS TRANSCRIPTIONAL ALTERATION OCCURRED IN ASSOCIATION WITH HDAC2-DEPENDENT REPRESSIVE HISTONE MODIFICATIONS AT THE MGLU2 PROMOTER. WE FOUND THAT CHRONIC CLOZAPINE TREATMENT DECREASED VIA HDAC2 THE CAPABILITIES OF THE MGLU2/3 RECEPTOR AGONIST LY379268 TO ACTIVATE G-PROTEINS IN THE FRONTAL CORTEX OF MICE. CHRONIC CLOZAPINE TREATMENT BLUNTED THE ANTIPSYCHOTIC-RELATED BEHAVIORAL EFFECTS OF LY379268, AN EFFECT THAT WAS NOT OBSERVED IN HDAC2 KNOCKOUT MICE. MORE IMPORTANTLY, CO-ADMINISTRATION OF THE CLASS I AND II HDAC INHIBITOR SAHA (VORINOSTAT) PRESERVED THE ANTIPSYCHOTIC PROFILE OF LY379268 AND FRONTAL CORTEX MGLU2/3 RECEPTOR DENSITY IN WILD-TYPE MICE. THESE FINDINGS RAISE CONCERNS ON THE DESIGN OF PREVIOUS CLINICAL STUDIES WITH MGLU2/3 AGONISTS, PROVIDING THE RATIONALE FOR THE DEVELOPMENT OF HDAC2 INHIBITORS AS A NEW EPIGENETIC-BASED APPROACH TO IMPROVE THE CURRENTLY LIMITED RESPONSE TO TREATMENT WITH GLUTAMATERGIC ANTIPSYCHOTICS. 2019 4 2249 48 EPIGENETIC MODULATION OF MGLU2 RECEPTORS BY HISTONE DEACETYLASE INHIBITORS IN THE TREATMENT OF INFLAMMATORY PAIN. KNOWING THAT EXPRESSION OF METABOTROPIC GLUTAMATE 2 (MGLU2) RECEPTORS IN THE DORSAL ROOT GANGLIA IS REGULATED BY ACETYLATION MECHANISMS, WE EXAMINED THE EFFECT OF TWO SELECTIVE AND CHEMICALLY UNRELATED HISTONE DEACETYLASE (HDAC) INHIBITORS, N-(2-AMINOPHENYL)-4-[N-(PYRIDINE-3-YLMETHOXY-CARBONYL)AMINOMETHYL]BENZAMIDE (MS-275) AND SUBEROYLANILIDE HYDROAMIC ACID (SAHA), IN A MOUSE MODEL OF PERSISTENT INFLAMMATORY PAIN. ALTHOUGH A SINGLE SUBCUTANEOUS INJECTION OF MS-275 (3 MG/KG) OR SAHA (5-50 MG/KG) WAS INEFFECTIVE, A 5-DAY TREATMENT WITH EITHER OF THE TWO HDAC INHIBITORS SUBSTANTIALLY REDUCED THE NOCICEPTIVE RESPONSE IN THE SECOND PHASE OF THE FORMALIN TEST, WHICH REFLECTS THE DEVELOPMENT OF CENTRAL SENSITIZATION IN THE DORSAL HORN OF THE SPINAL CORD. ANALGESIA WAS ABROGATED BY A SINGLE INJECTION OF THE MGLU2/3 RECEPTOR ANTAGONIST (ALPHAS)-ALPHA-AMINO-ALPHA-[(1S,2S)-2-CARBOXYCYCLOPROPYL]-9H-XANTINE-9-PROPANOIC ACID (LY341495; 1 MG/KG, I.P.), WHICH WAS INACTIVE PER SE. BOTH MS-275 AND SAHA UP-REGULATED THE EXPRESSION OF MGLU2 RECEPTORS IN THE DORSAL ROOT GANGLION (DRG) AND SPINAL CORD UNDER CONDITIONS IN WHICH THEY CAUSED ANALGESIA, WITHOUT CHANGING THE EXPRESSION OF MGLU1A, MGLU4, OR MGLU5 RECEPTORS. INDUCTION OF DRG MGLU2 RECEPTORS IN RESPONSE TO SAHA WAS ASSOCIATED WITH INCREASED ACETYLATION OF P65/RELA ON LYSINE 310, A PROCESS THAT ENHANCES THE TRANSCRIPTIONAL ACTIVITY OF P65/RELA AT NUCLEAR FACTOR-KAPPAB-REGULATED GENES. TRANSCRIPTION OF THE MGLU2 RECEPTOR GENE IS KNOWN TO BE ACTIVATED BY P65/RELA IN DRG NEURONS. WE CONCLUDE THAT HDAC INHIBITION PRODUCES ANALGESIA BY UP-REGULATING MGLU2 RECEPTOR EXPRESSION IN THE DRG, AN EFFECT THAT RESULTS FROM THE AMPLIFICATION OF NF-KAPPAB TRANSCRIPTIONAL ACTIVITY. THESE DATA PROVIDE THE FIRST EVIDENCE THAT HDAC INHIBITORS CAUSE ANALGESIA AND SUGGEST THAT HDACS ARE POTENTIAL TARGETS FOR THE EPIGENETIC TREATMENT OF PAIN. 2009 5 6536 35 TRANSCRIPTIONAL REGULATION OF TYPE-2 METABOTROPIC GLUTAMATE RECEPTORS: AN EPIGENETIC PATH TO NOVEL TREATMENTS FOR CHRONIC PAIN. ACTIVATION OF METABOTROPIC GLUTAMATE 2 (MGLU2) RECEPTORS INHIBITS PAIN TRANSMISSION AT THE SYNAPSES BETWEEN PRIMARY AFFERENT FIBERS AND NEURONS IN THE DORSAL HORN OF THE SPINAL CORD. IN ADDITION, MGLU2 RECEPTORS ARE FOUND IN PERIPHERAL NOCICEPTORS, AND IN PAIN-REGULATORY CENTERS OF THE BRAIN STEM AND FOREBRAIN. MGLU2 RECEPTOR AGONISTS PRODUCE ANALGESIA IN MODELS OF INFLAMMATORY AND NEUROPATHIC PAIN, BUT THEIR USE IS LIMITED BY THE DEVELOPMENT OF TOLERANCE. A NEW THERAPEUTIC STRATEGY COULD BE BASED ON THE TRANSCRIPTIONAL REGULATION OF MGLU2 RECEPTORS VIA THE ACETYLATION-PROMOTED ACTIVATION OF THE P65/RELA TRANSCRIPTION FACTOR. "EPIGENETIC" DRUGS THAT INCREASE MGLU2 RECEPTOR EXPRESSION, INCLUDING L-ACETYLCARNITINE AND INHIBITORS OF HISTONE DEACETYLASES, HAVE A DIFFERENT ANALGESIC PROFILE WITH NO TOLERANCE TO THE THERAPEUTIC EFFECT AFTER REPEATED DOSING. 2010 6 3191 47 HDAC AND HAT INHIBITORS DIFFERENTLY AFFECT ANALGESIA MEDIATED BY GROUP II METABOTROPIC GLUTAMATE RECEPTORS. BACKGROUND: HISTONE DEACETYLASES (HDACS) AND HISTONE ACETYLTRANSFERASES (HATS) ARE KEY PLAYERS IN EPIGENETIC REGULATION OF GENE EXPRESSION. ANALGESIC ACTIVITY BY HDAC INHIBITORS HAS BEEN REPORTED IN DIFFERENT PAIN MODELS INCLUDING INFLAMMATORY AND NEUROPATHIC PAIN. THESE DRUGS INTERFERE WITH GENE EXPRESSION THROUGH DIFFERENT MECHANISMS INCLUDING CHROMATIN REMODELING AND/OR ACTIVATION OF TRANSCRIPTION FACTORS. AMONG OTHER TARGETS, HDAC INHIBITORS REGULATE METABOTROPIC GLUTAMATE RECEPTORS TYPE 2 (MGLU2) EXPRESSION IN CENTRAL AND PERIPHERAL CENTRAL NERVOUS SYSTEM. HOWEVER WHETHER INHIBITION OF HAT ACTIVITY ALSO REGULATES MGLU2 EXPRESSION HAS NOT BEEN REPORTED. FINDINGS: HERE WE REPORT THAT CURCUMIN (CUR), A NATURALLY OCCURRING COMPOUND ENDOWED WITH P300/CREB-BINDING PROTEIN HAT INHIBITORY ACTIVITY, IS ABLE TO INDUCE A DRASTIC DOWN-REGULATION OF THE MGLU2 RECEPTOR IN THE MOUSE SPINAL CORD AFTER SYSTEMIC ADMINISTRATION TOGETHER WITH A MARKED HYPOACETYLATION OF HISTONES H3 AND H4 IN DORSAL ROOT GANGLIA (DRG). FURTHERMORE, THE ANALGESIC ACTIVITY OF THE MGLU2/3 AGONIST, LY379268 IS LOST AFTER A 3-DAY TREATMENT WITH CUR. CONVERSELY THE ANALGESIC ACTIVITY OF LY379268 IS POTENTIATED IN MICE PRETREATED FOR 5 CONSECUTIVE DAYS WITH THE HDAC INHIBITOR, SUBEROYLANILIDE HYDROXAMIC ACID (SAHA), KNOWN TO INDUCE MGLU2-UPREGULATION. CONCLUSIONS: OUR RESULTS DEMONSTRATE THAT SYSTEMICALLY INJECTED CUR IS ABLE TO INHIBIT H3 AND H4 ACETYLATION IN THE DRG AND TO DOWN-REGULATE MGLU2 RECEPTORS IN THE SPINAL CORD. WE ALSO DEMONSTRATE THAT LONG TERM MODIFICATION OF THE MGLU2 EXPRESSION AFFECTS THE ANALGESIC PROPERTIES OF THE ORTHOSTERIC MGLU2/3 AGONIST, LY379268. THESE DATA OPEN UP THE POSSIBILITY THAT EPIGENETIC MODULATORS MIGHT BE GIVEN IN COMBINATION WITH "TRADITIONAL" DRUGS IN A CONTEXT OF A MULTI TARGET APPROACH FOR A BETTER ANALGESIC EFFICACY. 2014 7 3892 36 L-ACETYLCARNITINE CAUSES RAPID ANTIDEPRESSANT EFFECTS THROUGH THE EPIGENETIC INDUCTION OF MGLU2 RECEPTORS. EPIGENETIC MECHANISMS ARE INVOLVED IN THE PATHOPHYSIOLOGY OF DEPRESSIVE DISORDERS AND ARE UNIQUE POTENTIAL TARGETS FOR THERAPEUTIC INTERVENTION. THE ACETYLATING AGENT L-ACETYLCARNITINE (LAC), A WELL-TOLERATED DRUG, BEHAVES AS AN ANTIDEPRESSANT BY THE EPIGENETIC REGULATION OF TYPE 2 METABOTROPIC GLUTAMATE (MGLU2) RECEPTORS. IT CAUSED A RAPID AND LONG-LASTING ANTIDEPRESSANT EFFECT IN FLINDERS SENSITIVE LINE RATS AND IN MICE EXPOSED TO CHRONIC UNPREDICTABLE STRESS, WHICH, RESPECTIVELY, MODEL GENETIC AND ENVIRONMENTALLY INDUCED DEPRESSION. IN BOTH MODELS, LAC INCREASED LEVELS OF ACETYLATED H3K27 BOUND TO THE GRM2 PROMOTER AND ALSO INCREASED ACETYLATION OF NF-KB-P65 SUBUNIT, THEREBY ENHANCING THE TRANSCRIPTION OF GRM2 GENE ENCODING FOR THE MGLU2 RECEPTOR IN HIPPOCAMPUS AND PREFRONTAL CORTEX. IMPORTANTLY, LAC REDUCED THE IMMOBILITY TIME IN THE FORCED SWIM TEST AND INCREASED SUCROSE PREFERENCE AS EARLY AS 3 D OF TREATMENT, WHEREAS 14 D OF TREATMENT WERE NEEDED FOR THE ANTIDEPRESSANT EFFECT OF CHLORIMIPRAMINE. MOREOVER, THERE WAS NO TOLERANCE TO THE ACTION OF LAC, AND THE ANTIDEPRESSANT EFFECT WAS STILL SEEN 2 WK AFTER DRUG WITHDRAWAL. CONVERSELY, NF-KB INHIBITION PREVENTED THE INCREASE IN MGLU2 EXPRESSION INDUCED BY LAC, WHEREAS THE USE OF A HISTONE DEACETYLASE INHIBITOR SUPPORTED THE EPIGENETIC CONTROL OF MGLU2 EXPRESSION. FINALLY, LAC HAD NO EFFECT ON MGLU2 KNOCKOUT MICE EXPOSED TO CHRONIC UNPREDICTABLE STRESS, AND A SINGLE INJECTION OF THE MGLU2/3 RECEPTOR ANTAGONIST LY341495 PARTIALLY BLOCKED LAC ACTION. THE RAPID AND LONG-LASTING ANTIDEPRESSANT ACTION OF LAC STRONGLY SUGGESTS A UNIQUE APPROACH TO EXAMINE THE EPIGENETIC HYPOTHESIS OF DEPRESSIVE DISORDERS IN HUMANS, PAVING THE WAY FOR MORE EFFICIENT ANTIDEPRESSANTS WITH FASTER ONSET OF ACTION. 2013 8 2826 30 FLUOXETINE EPIGENETICALLY ALTERS THE CAMKIIALPHA PROMOTER IN NUCLEUS ACCUMBENS TO REGULATE DELTAFOSB BINDING AND ANTIDEPRESSANT EFFECTS. CHRONIC SOCIAL DEFEAT STRESS IN MICE PRODUCES A SUSCEPTIBLE PHENOTYPE CHARACTERIZED BY SEVERAL BEHAVIORAL ABNORMALITIES CONSISTENT WITH HUMAN DEPRESSION THAT ARE REVERSED BY CHRONIC BUT NOT ACUTE EXPOSURE TO ANTIDEPRESSANT MEDICATIONS. RECENT WORK IN ADDICTION MODELS DEMONSTRATES THAT THE TRANSCRIPTION FACTOR DELTAFOSB AND PROTEIN KINASE CALMODULIN-DEPENDENT PROTEIN KINASE II (CAMKII) ARE CO-REGULATED IN NUCLEUS ACCUMBENS (NAC), A BRAIN REWARD REGION IMPLICATED IN BOTH ADDICTION AND DEPRESSION MODELS INCLUDING SOCIAL DEFEAT. PREVIOUS WORK HAS ALSO DEMONSTRATED THAT DELTAFOSB IS INDUCED IN NAC AFTER CHRONIC SOCIAL DEFEAT STRESS OR AFTER CHRONIC ANTIDEPRESSANT TREATMENT, WHEREIN IT MEDIATES A PRO-RESILIENCE OR ANTIDEPRESSANT-LIKE PHENOTYPE. HERE, USING CHROMATIN IMMUNOPRECIPITATION ASSAYS, WE FOUND THAT DELTAFOSB BINDS THE CAMKIIALPHA GENE PROMOTER IN NAC AND THAT THIS BINDING INCREASES AFTER MICE ARE EXPOSED TO CHRONIC SOCIAL DEFEAT STRESS. PARADOXICALLY, CHRONIC EXPOSURE TO THE ANTIDEPRESSANT FLUOXETINE REDUCES BINDING OF DELTAFOSB TO THE CAMKIIALPHA PROMOTER AND REDUCES CAMKII EXPRESSION IN NAC, DESPITE THE FACT THAT DELTAFOSB IS INDUCED UNDER THESE CONDITIONS. THESE DATA SUGGEST A NOVEL EPIGENETIC MECHANISM OF ANTIDEPRESSANT ACTION, WHEREBY FLUOXETINE INDUCES SOME CHROMATIN CHANGE AT THE CAMKIIALPHA PROMOTER, WHICH BLOCKS THE DELTAFOSB BINDING. INDEED, CHRONIC FLUOXETINE REDUCES ACETYLATION AND INCREASES LYSINE-9 DIMETHYLATION OF HISTONE H3 AT THE CAMKIIALPHA PROMOTER IN NAC, EFFECTS ALSO SEEN IN DEPRESSED HUMANS EXPOSED TO ANTIDEPRESSANTS. OVEREXPRESSION OF CAMKII IN NAC BLOCKS FLUOXETINE'S ANTIDEPRESSANT EFFECTS IN THE CHRONIC SOCIAL DEFEAT PARADIGM, WHEREAS INHIBITION OF CAMKII ACTIVITY IN NAC MIMICS FLUOXETINE EXPOSURE. THESE FINDINGS SUGGEST THAT EPIGENETIC SUPPRESSION OF CAMKIIALPHA EXPRESSION IN NAC IS BEHAVIORALLY RELEVANT AND OFFER A NOVEL PATHWAY FOR POSSIBLE THERAPEUTIC INTERVENTION IN DEPRESSION AND RELATED SYNDROMES. 2014 9 3202 37 HDAC2 REGULATES ATYPICAL ANTIPSYCHOTIC RESPONSES THROUGH THE MODULATION OF MGLU2 PROMOTER ACTIVITY. HISTONE DEACETYLASES (HDACS) COMPACT CHROMATIN STRUCTURE AND REPRESS GENE TRANSCRIPTION. IN SCHIZOPHRENIA, CLINICAL STUDIES DEMONSTRATE THAT HDAC INHIBITORS ARE EFFICACIOUS WHEN GIVEN IN COMBINATION WITH ATYPICAL ANTIPSYCHOTICS. HOWEVER, THE MOLECULAR MECHANISM THAT INTEGRATES A BETTER RESPONSE TO ANTIPSYCHOTICS WITH CHANGES IN CHROMATIN STRUCTURE REMAINS UNKNOWN. HERE WE FOUND THAT CHRONIC ATYPICAL ANTIPSYCHOTICS DOWNREGULATED THE TRANSCRIPTION OF METABOTROPIC GLUTAMATE 2 RECEPTOR (MGLU2, ALSO KNOWN AS GRM2), AN EFFECT THAT WAS ASSOCIATED WITH DECREASED HISTONE ACETYLATION AT ITS PROMOTER IN MOUSE AND HUMAN FRONTAL CORTEX. THIS EPIGENETIC CHANGE OCCURRED IN CONCERT WITH A SEROTONIN 5-HT(2A) RECEPTOR-DEPENDENT UPREGULATION AND INCREASED BINDING OF HDAC2 TO THE MGLU2 PROMOTER. VIRALLY MEDIATED OVEREXPRESSION OF HDAC2 IN FRONTAL CORTEX DECREASED MGLU2 TRANSCRIPTION AND ITS ELECTROPHYSIOLOGICAL PROPERTIES, THEREBY INCREASING PSYCHOSIS-LIKE BEHAVIOR. CONVERSELY, HDAC INHIBITORS PREVENTED THE REPRESSIVE HISTONE MODIFICATIONS INDUCED AT THE MGLU2 PROMOTER BY ATYPICAL ANTIPSYCHOTICS, AND AUGMENTED THEIR THERAPEUTIC-LIKE EFFECTS. THESE OBSERVATIONS SUPPORT THE VIEW OF HDAC2 AS A PROMISING NEW TARGET FOR SCHIZOPHRENIA TREATMENT. 2012 10 3196 30 HDAC INHIBITORS RESTORE C-FIBRE SENSITIVITY IN EXPERIMENTAL NEUROPATHIC PAIN MODEL. BACKGROUND AND PURPOSE: HYPOESTHESIA IS A CLINICAL FEATURE OF NEUROPATHIC PAIN. THE FEATURE IS PARTLY EXPLAINED BY THE EVIDENCE OF EPIGENETIC REPRESSION OF NAV 1.8 SODIUM CHANNEL IN THE DORSAL ROOT GANGLION (DRG). EXPERIMENTAL APPROACH: WE INVESTIGATED THE POSSIBILITY OF TRICHOSTATIN A (TSA), VALPROIC ACID (VPA) AND SUBEROYLANILIDE HYDROXAMIC ACID (SAHA) TO REVERSE THE UNIQUE C-FIBRE SENSITIVITY OBSERVED FOLLOWING PARTIAL LIGATION OF SCIATIC NERVE IN MICE. KEY RESULTS: NERVE INJURY-INDUCED DOWN-REGULATION OF DRG NAV 1.8 SODIUM CHANNEL AND C-FIBRE-RELATED HYPOESTHESIA WERE REVERSED BY TSA, VPA AND SAHA TREATMENTS, WHICH INHIBIT HISTONE DEACETYLASE (HDAC), AND INCREASE HISTONE ACETYLATION AT THE REGULATORY SEQUENCE OF NAV 1.8. CONCLUSIONS AND IMPLICATIONS: TAKEN TOGETHER, THESE STUDIES PROVIDE THE EVIDENCE THAT HYPOESTHESIA AND UNDERLYING DOWN-REGULATION OF NAV 1.8, NEGATIVE SYMPTOMS OBSERVED IN NERVE INJURY-INDUCED NEUROPATHIC PAIN MODELS ARE REGULATED BY AN EPIGENETIC CHROMATIN REMODELLING THROUGH HDAC-RELATED MACHINERIES. 2013 11 400 46 ANALGESIA INDUCED BY THE EPIGENETIC DRUG, L-ACETYLCARNITINE, OUTLASTS THE END OF TREATMENT IN MOUSE MODELS OF CHRONIC INFLAMMATORY AND NEUROPATHIC PAIN. BACKGROUND L-ACETYLCARNITINE, A DRUG MARKETED FOR THE TREATMENT OF CHRONIC PAIN, CAUSES ANALGESIA BY EPIGENETICALLY UP-REGULATING TYPE-2 METABOTROPIC GLUTAMATE (MGLU2) RECEPTORS IN THE SPINAL CORD. BECAUSE THE EPIGENETIC MECHANISMS ARE TYPICALLY LONG-LASTING, WE HYPOTHESIZED THAT ANALGESIA COULD OUTLAST THE DURATION OF L-ACETYLCARNITINE TREATMENT IN MODELS OF INFLAMMATORY AND NEUROPATHIC PAIN. RESULTS A SEVEN-DAY TREATMENT WITH L-ACETYLCARNITINE (100 MG/KG, ONCE A DAY, I.P.) PRODUCED AN ANTIALLODYNIC EFFECT IN THE COMPLETE FREUND ADJUVANT MOUSE MODEL OF CHRONIC INFLAMMATORY PAIN. L-ACETYLCARNITINE-INDUCED ANALGESIA PERSISTED FOR AT LEAST 14 DAYS AFTER DRUG WITHDRAWAL. IN CONTRAST, THE ANALGESIC EFFECT OF PREGABALIN, AMITRYPTILINE, CEFTRIAXONE, AND N-ACETYLCYSTEINE DISAPPEARED SEVEN DAYS AFTER DRUG WITHDRAWAL. L-ACETYLCARNITINE TREATMENT ENHANCED MGLU2/3 RECEPTOR PROTEIN LEVELS IN THE DORSAL REGION OF THE SPINAL CORD. THIS EFFECT ALSO PERSISTED FOR TWO WEEKS AFTER DRUG WITHDRAWAL AND WAS ASSOCIATED WITH INCREASED LEVELS OF ACETYLATED HISTONE H3 BOUND TO THE GRM2 GENE PROMOTER IN THE DORSAL ROOT GANGLIA. A LONG-LASTING ANALGESIC EFFECT OF L-ACETYLCARNITINE WAS ALSO OBSERVED IN MICE SUBJECTED TO CHRONIC CONSTRICTION INJURY OF THE SCIATIC NERVE. IN THESE ANIMALS, A 14-DAY TREATMENT WITH PREGABALIN, AMITRYPTILINE, TRAMADOL, OR L-ACETYLCARNITINE PRODUCED A SIGNIFICANT ANTIALLODYNIC EFFECT, WITH PREGABALIN DISPLAYING THE GREATEST EFFICACY. IN MICE TREATED WITH PREGABALIN, TRAMADOL OR L-ACETYLCARNITINE THE ANALGESIC EFFECT WAS STILL VISIBLE 15 DAYS AFTER THE END OF DRUG TREATMENT. HOWEVER, ONLY IN MICE TREATED WITH L-ACETYLCARNITINE ANALGESIA PERSISTED 37 DAYS AFTER DRUG WITHDRAWAL. THIS EFFECT WAS ASSOCIATED WITH AN INCREASE IN MGLU2/3 RECEPTOR PROTEIN LEVELS IN THE DORSAL HORNS OF THE SPINAL CORD. CONCLUSIONS OUR FINDINGS SUGGEST THAT L-ACETYLCARNITINE HAS THE UNIQUE PROPERTY TO CAUSE A LONG-LASTING ANALGESIC EFFECT THAT MIGHT REDUCE RELAPSES IN PATIENTS SUFFERING FROM CHRONIC PAIN. 2017 12 6170 37 THE HDAC INHIBITOR SAHA IMPROVES DEPRESSIVE-LIKE BEHAVIOR OF CRTC1-DEFICIENT MICE: POSSIBLE RELEVANCE FOR TREATMENT-RESISTANT DEPRESSION. MAJOR DEPRESSION IS A HIGHLY COMPLEX DISABLING PSYCHIATRIC DISORDER AFFECTING MILLIONS OF PEOPLE WORLDWIDE. DESPITE THE AVAILABILITY OF SEVERAL CLASSES OF ANTIDEPRESSANTS, A SUBSTANTIAL PERCENTAGE OF PATIENTS ARE UNRESPONSIVE TO THESE MEDICATIONS. A BETTER UNDERSTANDING OF THE NEUROBIOLOGY OF DEPRESSION AND THE MECHANISMS UNDERLYING ANTIDEPRESSANT RESPONSE IS THUS CRITICALLY NEEDED. WE PREVIOUSLY REPORTED THAT MICE LACKING CREB-REGULATED TRANSCRIPTION COACTIVATOR 1 (CRTC1) EXHIBIT A DEPRESSIVE-LIKE PHENOTYPE AND A BLUNTED ANTIDEPRESSANT RESPONSE TO THE SELECTIVE SEROTONIN REUPTAKE INHIBITOR FLUOXETINE. IN THIS STUDY, WE SIMILARLY SHOW THAT CRTC1(-/-) MICE ARE RESISTANT TO THE ANTIDEPRESSANT EFFECT OF CHRONIC DESIPRAMINE IN A BEHAVIORAL DESPAIR PARADIGM. SUPPORTING THE BLUNTED RESPONSE TO THIS TRICYCLIC ANTIDEPRESSANT, WE FOUND THAT DESIPRAMINE DOES NOT SIGNIFICANTLY INCREASE THE EXPRESSION OF BDNF AND NR4A1-3 IN THE HIPPOCAMPUS AND PREFRONTAL CORTEX OF CRTC1(-/-) MICE. EPIGENETIC REGULATION OF NEUROPLASTICITY GENE EXPRESSION HAS BEEN ASSOCIATED WITH DEPRESSION AND ANTIDEPRESSANT RESPONSE, AND HISTONE DEACETYLASE (HDAC) INHIBITORS HAVE BEEN SHOWN TO HAVE ANTIDEPRESSANT-LIKE PROPERTIES. HERE, WE SHOW THAT UNLIKE CONVENTIONAL ANTIDEPRESSANTS, CHRONIC SYSTEMIC ADMINISTRATION OF THE HDAC INHIBITOR SAHA PARTIALLY RESCUES THE DEPRESSIVE-LIKE BEHAVIOR OF CRTC1(-/-) MICE. THIS BEHAVIORAL EFFECT IS ACCOMPANIED BY AN INCREASED EXPRESSION OF BDNF, BUT NOT NR4A1-3, IN THE PREFRONTAL CORTEX OF THESE MICE, SUGGESTING THAT THIS EPIGENETIC INTERVENTION RESTORES THE EXPRESSION OF A SUBSET OF GENES BY ACTING DOWNSTREAM OF CRTC1. THESE FINDINGS SUGGEST THAT CRTC1 ALTERATIONS MAY BE ASSOCIATED WITH TREATMENT-RESISTANT DEPRESSION, AND SUPPORT THE INTERESTING POSSIBILITY THAT TARGETING HDACS MAY BE A USEFUL THERAPEUTIC STRATEGY IN ANTIDEPRESSANT DEVELOPMENT. 2016 13 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 14 1856 28 ELEVATION OF N-ACETYLTRANSFERASE 10 IN HIPPOCAMPAL NEURONS MEDIATES DEPRESSION- AND ANXIETY-LIKE BEHAVIORS. MAJOR DEPRESSIVE DISORDER (MDD) IS ONE OF THE MOST DEBILITATING AND SEVERE MENTAL DISEASES GLOBALLY. INCREASING EVIDENCE HAS SHOWN THAT EPIGENETICS IS CRITICAL FOR UNDERSTANDING BRAIN FUNCTION AND BRAIN DISORDERS, INCLUDING MDD. N-ACETYLTRANSFERASE 10 (NAT10), ACTING ON HISTONES, MRNA AND OTHER SUBSTRATES, HAS BEEN REPORTED TO BE INVOLVED IN EPIGENETIC EVENTS, INCLUDING HISTONE ACETYLATION AND MRNA MODIFICATIONS. NAT10 IS HIGHLY EXPRESSED IN THE BRAIN. HOWEVER, THE POTENTIAL EFFECTS OF NAT10 ON MDD ARE STILL UNKNOWN. HERE, WE EXPLOITED CHRONIC MILD STRESS (CMS) TO INDUCE ANXIETY- AND DEPRESSION-LIKE BEHAVIORS IN MICE AND FOUND THAT THE EXPRESSION OF NAT10 IN THE MOUSE HIPPOCAMPUS WAS UPREGULATED AFTER CMS TREATMENT. INHIBITION OF NAT10 BY PHARMACOLOGICAL METHODS PRODUCED ANXIOLYTIC- AND ANTIDEPRESSANT-LIKE EFFECTS. NEURON-SPECIFIC OVEREXPRESSION OF NAT10 IN THE HIPPOCAMPUS RESULTED IN ANXIETY- AND DEPRESSION-LIKE BEHAVIORS, ACCOMPANIED BY HIGHER SIRT1 PROTEIN LEVELS, AND LOWER DENDRITIC SPINE DENSITIES. OVERALL, IT WAS FOUND THAT ELEVATION OF NAT10 IN HIPPOCAMPAL NEURONS IS INVOLVED IN THE OCCURRENCE OF ANXIETY- AND DEPRESSION-LIKE BEHAVIORS, SUGGESTING THAT NAT10 COULD BE A POTENTIAL NEW TARGET FOR DEVELOPING ANXIOLYTICS AND ANTIDEPRESSANTS. 2022 15 1653 43 DOPAMINE TRANSPORTER KNOCKOUT RATS DISPLAY EPIGENETIC ALTERATIONS IN RESPONSE TO COCAINE EXPOSURE. (1) BACKGROUND: THERE IS AN URGENT NEED FOR EFFECTIVE TREATMENTS FOR COCAINE USE DISORDER (CUD), AND NEW PHARMACOLOGICAL APPROACHES TARGETING EPIGENETIC MECHANISMS APPEAR TO BE PROMISING OPTIONS FOR THE TREATMENT OF THIS DISEASE. DOPAMINE TRANSPORTER (DAT) TRANSGENIC RATS RECENTLY HAVE BEEN PROPOSED AS A NEW ANIMAL MODEL FOR STUDYING SUSCEPTIBILITY TO CUD. (2) METHODS: DAT TRANSGENIC RATS WERE TREATED CHRONICALLY WITH COCAINE (10 MG/KG) FOR 8 DAYS, AND THE EXPRESSION OF EPIGENETIC MODULATORS, LYSINE DEMETHYLASE 6B (KDM6B) AND BROMODOMAIN-CONTAINING PROTEIN 4 (BRD4), WAS EXAMINED IN THE PREFRONTAL CORTEX (PFC). (3) RESULTS: WE SHOW THAT ONLY FULL KNOCKOUT (KO) OF DAT IMPACTS BASAL LEVELS OF KDM6B IN FEMALES. ADDITIONALLY, COCAINE ALTERED THE EXPRESSION OF BOTH EPIGENETIC MARKERS IN A SEX- AND GENOTYPE-DEPENDENT MANNER. IN RESPONSE TO CHRONIC COCAINE, KDM6B EXPRESSION WAS DECREASED IN MALE RATS WITH PARTIAL DAT MUTATION (HET), WHILE NO CHANGES WERE OBSERVED IN WILD-TYPE (WT) OR KO RATS. INDEED, WHILE HET MALE RATS HAVE REDUCED KDM6B AND BRD4 EXPRESSION, HET FEMALE RATS SHOWED INCREASED KDM6B AND BRD4 EXPRESSION LEVELS, HIGHLIGHTING THE IMPACT OF SEX ON EPIGENETIC MECHANISMS IN RESPONSE TO COCAINE. FINALLY, BOTH MALE AND FEMALE KO RATS SHOWED INCREASED EXPRESSION OF BRD4, BUT ONLY KO FEMALES EXHIBITED SIGNIFICANTLY INCREASED KDM6B EXPRESSION IN RESPONSE TO COCAINE. ADDITIONALLY, THE MAGNITUDE OF THESE EFFECTS WAS BIGGER IN FEMALES WHEN COMPARED TO MALES FOR BOTH EPIGENETIC ENZYMES. (4) CONCLUSIONS: THIS PRELIMINARY STUDY PROVIDES ADDITIONAL SUPPORT THAT TARGETING KDM6B AND/OR BRD4 MAY POTENTIALLY BE THERAPEUTIC IN TREATING ADDICTION-RELATED BEHAVIORS IN A SEX-DEPENDENT MANNER. 2023 16 3331 39 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 17 869 32 CHRONIC AGOMELATINE TREATMENT CORRECTS BEHAVIORAL, CELLULAR, AND BIOCHEMICAL ABNORMALITIES INDUCED BY PRENATAL STRESS IN RATS. RATIONALE AND OBJECTIVES: THE RAT MODEL OF PRENATAL RESTRAINT STRESS (PRS) REPLICATES FACTORS THAT ARE IMPLICATED IN THE ETIOLOGY OF ANXIOUS/DEPRESSIVE DISORDERS. WE USED THIS MODEL TO TEST THE THERAPEUTIC EFFICACY OF AGOMELATINE, A NOVEL ANTIDEPRESSANT THAT BEHAVES AS A MIXED MT1/MT2 MELATONIN RECEPTOR AGONIST/5-HT(2C) SEROTONIN RECEPTOR ANTAGONIST. RESULTS: ADULT PRS RATS SHOWED BEHAVIORAL, CELLULAR, AND BIOCHEMICAL ABNORMALITIES THAT WERE CONSISTENT WITH AN ANXIOUS/DEPRESSIVE PHENOTYPE. THESE INCLUDED AN INCREASED IMMOBILITY IN THE FORCED SWIM TEST, AN ANXIETY-LIKE BEHAVIOR IN THE ELEVATED PLUS MAZE, REDUCED HIPPOCAMPAL LEVELS OF PHOSPHORYLATED CAMP-RESPONSIVE ELEMENT BINDING PROTEIN (P-CREB), REDUCED HIPPOCAMPAL LEVELS OF MGLU2/3 AND MGLU5 METABOTROPIC GLUTAMATE RECEPTORS, AND REDUCED NEUROGENESIS IN THE VENTRAL HIPPOCAMPUS, THE SPECIFIC PORTION OF THE HIPPOCAMPUS THAT ENCODES MEMORIES RELATED TO STRESS AND EMOTIONS. ALL OF THESE CHANGES WERE REVERSED BY A 3- OR 6-WEEK TREATMENT WITH AGOMELATINE (40-50 MG/KG, I.P., ONCE A DAY). REMARKABLY, AGOMELATINE HAD NO EFFECT IN AGE-MATCHED CONTROL RATS, THEREBY BEHAVING AS A "DISEASE-DEPENDENT" DRUG. CONCLUSIONS: THESE DATA INDICATE THAT AGOMELATINE DID NOT ACT ON INDIVIDUAL SYMPTOMS BUT CORRECTED ALL ASPECTS OF THE PATHOLOGICAL EPIGENETIC PROGRAMMING TRIGGERED BY PRS. OUR FINDINGS STRONGLY SUPPORT THE ANTIDEPRESSANT ACTIVITY OF AGOMELATINE AND SUGGEST THAT THE DRUG IMPACTS MECHANISMS THAT LIE AT THE CORE OF ANXIOUS/DEPRESSIVE DISORDERS. 2011 18 1999 31 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 19 1120 31 COMPARISON OF DIFFERENT HISTONE DEACETYLASE INHIBITORS IN ATTENUATING INFLAMMATORY PAIN IN RATS. HISTONE DEACETYLASE INHIBITORS (HDACIS), WHICH INTERFERE WITH THE EPIGENETIC PROCESS OF HISTONE ACETYLATION, HAVE SHOWN ANALGESIC EFFECTS IN ANIMAL MODELS OF PERSISTENT PAIN. THE HDAC FAMILY COMPRISES 18 GENES; HOWEVER, THE DIFFERENT EFFECTS OF DISTINCT CLASSES OF HDACIS ON PAIN RELIEF REMAIN UNCLEAR. THE AIM OF THIS STUDY WAS TO DETERMINE THE EFFICACY OF THESE HDACIS ON ATTENUATING THERMAL HYPERALGESIA IN PERSISTENT INFLAMMATORY PAIN. PERSISTENT INFLAMMATORY PAIN WAS INDUCED BY INJECTING COMPLETE FREUND'S ADJUVANT (CFA) INTO THE LEFT HIND PAW OF RATS. THEN, HDACIS TARGETING CLASS I (ENTINOSTAT (MS-275)) AND CLASS IIA (SODIUM BUTYRATE, VALPROIC ACID (VPA), AND 4-PHENYLBUTYRIC ACID (4-PBA)), OR CLASS II (SUBEROYLANILIDE HYDOXAMIC ACID (SAHA), TRICHOSTATIN A (TSA), AND DACINOSTAT (LAQ824)) WERE ADMINISTERED INTRAPERITONEALLY ONCE DAILY FOR 3 OR 4 DAYS. WE FOUND THAT THE INJECTION OF SAHA ONCE A DAY FOR 3 DAYS SIGNIFICANTLY ATTENUATED CFA-INDUCED THERMAL HYPERALGESIA FROM DAY 4 AND LASTED 7 DAYS. IN COMPARISON WITH SAHA, SUPPRESSION OF HYPERALGESIA BY 4-PBA PEAKED ON DAY 2, WHEREAS THAT BY MS-275 OCCURRED ON DAYS 5 AND 6. FATIGUE WAS A SERIOUS SIDE EFFECT SEEN WITH MS-275. THESE FINDINGS WILL BE BENEFICIAL FOR OPTIMIZING THE SELECTION OF SPECIFIC HDACIS IN MEDICAL FIELDS SUCH AS PAIN MEDICINE AND NEUROPSYCHIATRY. 2019 20 5712 35 SIRT1 MEDIATES DEPRESSION-LIKE BEHAVIORS IN THE NUCLEUS ACCUMBENS. DEPRESSION IS A RECURRING AND LIFE-THREATENING ILLNESS THAT AFFECTS UP TO 120 MILLION PEOPLE WORLDWIDE. IN THE PRESENT STUDY, WE SHOW THAT CHRONIC SOCIAL DEFEAT STRESS, AN ETHOLOGICALLY VALIDATED MODEL OF DEPRESSION IN MICE, INCREASES SIRT1 LEVELS IN THE NUCLEUS ACCUMBENS (NAC), A KEY BRAIN REWARD REGION. INCREASES IN SIRT1, A WELL CHARACTERIZED CLASS III HISTONE DEACETYLASE, AFTER CHRONIC SOCIAL DEFEAT SUGGEST A ROLE FOR THIS ENZYME IN MEDIATING DEPRESSION-LIKE BEHAVIORS. WHEN RESVERATROL, A PHARMACOLOGICAL ACTIVATOR OF SIRT1, WAS DIRECTLY INFUSED BILATERALLY INTO THE NAC, WE OBSERVED AN INCREASE IN DEPRESSION- AND ANXIETY-LIKE BEHAVIORS. CONVERSELY, INTRA-NAC INFUSIONS OF EX-527, A SIRT1 ANTAGONIST, REDUCED THESE BEHAVIORS; EX-527 ALSO REDUCED ACUTE STRESS RESPONSES IN STRESS-NAIVE MICE. NEXT, WE INCREASED SIRT1 LEVELS DIRECTLY IN NAC BY USE OF VIRAL-MEDIATED GENE TRANSFER AND OBSERVED AN INCREASE IN DEPRESSIVE- AND ANXIETY-LIKE BEHAVIORS WHEN MICE WERE ASSESSED IN THE OPEN-FIELD, ELEVATED-PLUS-MAZE, AND FORCED SWIM TESTS. USING A CRE-INDUCIBLE VIRAL VECTOR SYSTEM TO OVEREXPRESS SIRT1 SELECTIVELY IN DOPAMINE D1 OR D2 SUBPOPULATIONS OF MEDIUM SPINY NEURONS (MSNS) IN THE NAC, WE FOUND THAT SIRT1 PROMOTES DEPRESSIVE-LIKE BEHAVIORS ONLY WHEN OVEREXPRESSED IN D1 MSNS, WITH NO EFFECT SEEN IN D2 MSNS. CONVERSELY, SELECTIVE ABLATION OF SIRT1 IN THE NAC USING VIRAL-CRE IN FLOXED SIRT1 MICE RESULTED IN DECREASED DEPRESSION- AND ANXIETY-LIKE BEHAVIORS. TOGETHER, THESE RESULTS DEMONSTRATE THAT SIRT1 PLAYS AN ESSENTIAL ROLE IN THE NAC IN REGULATING MOOD-RELATED BEHAVIORAL ABNORMALITIES AND IDENTIFIES A NOVEL SIGNALING PATHWAY FOR THE DEVELOPMENT OF INNOVATIVE ANTIDEPRESSANTS TO TREAT MAJOR DEPRESSIVE DISORDERS. SIGNIFICANCE STATEMENT: IN THIS STUDY, WE DEMONSTRATE A PIVOTAL ROLE FOR SIRT1 IN ANXIETY- AND DEPRESSION-LIKE BEHAVIORS IN THE NUCLEUS ACCUMBENS (NAC), A KEY BRAIN REWARD REGION. WE SHOW THAT STRESS STABLY INDUCES SIRT1 EXPRESSION IN THIS BRAIN REGION AND THAT ALTERING SIRT1 ACTIVITY USING A PHARMACOLOGICAL OR GENETIC APPROACH REGULATES ANXIETY- AND DEPRESSION-LIKE BEHAVIORS. THESE RESULTS SUGGEST THAT SIRT1 PLAYS AN ESSENTIAL ROLE IN REGULATING MOOD-RELATED BEHAVIORS AND INTRODUCES A NOVEL SIGNALING PATHWAY FOR THE DEVELOPMENT OF INNOVATIVE ANTIDEPRESSANTS TO TREAT DEPRESSION AND OTHER STRESS-RELATED DISORDERS. A RECENT GROUNDBREAKING PUBLICATION BY THE CONVERGE CONSORTIUM (2015) IDENTIFIED A REPRODUCIBLE ASSOCIATION OF THE SIRT1 LOCUS WITH MAJOR DEPRESSION IN HUMANS. THEREFORE, OUR RESULTS ARE TIMELY AND HAVE SIGNIFICANT TRANSLATIONAL RELEVANCE. 2016