1 2839 130 FOSB INDUCTION IN NUCLEUS ACCUMBENS BY COCAINE IS REGULATED BY E2F3A. THE TRANSCRIPTION FACTOR DELTAFOSB HAS BEEN PROPOSED AS A MOLECULAR SWITCH FOR THE TRANSITION FROM CASUAL, VOLITIONAL DRUG USE INTO A CHRONICALLY ADDICTED STATE, BUT THE UPSTREAM REGULATORY MECHANISMS GOVERNING DELTAFOSB EXPRESSION ARE INCOMPLETELY UNDERSTOOD. IN THIS STUDY, WE FIND A NOVEL REGULATORY ROLE FOR THE TRANSCRIPTION FACTOR E2F3, RECENTLY IMPLICATED IN TRANSCRIPTIONAL REGULATION BY COCAINE, IN CONTROLLING DELTAFOSB INDUCTION IN THE MOUSE NUCLEUS ACCUMBENS (NAC) FOLLOWING COCAINE ADMINISTRATION. WE FIND THAT AN E2F CONSENSUS SEQUENCE 500 BP UPSTREAM OF THE FOSB TRANSCRIPTION START SITE IS ENRICHED FOR E2F3 SPECIFICALLY OVER OTHER E2F ISOFORMS. WE FURTHER CONCLUDE THAT DELTAFOSB EXPRESSION IS REGULATED SPECIFICALLY BY E2F3A, NOT E2F3B, THAT E2F3A EXPRESSION IS SPECIFIC TO D1 RECEPTOR-EXPRESSING MEDIUM SPINY NEURONS, AND THAT E2F3A OVEREXPRESSION IN NAC RECAPITULATES THE INDUCTION OF FOSB AND DELTAFOSB MRNA EXPRESSION OBSERVED AFTER CHRONIC COCAINE EXPOSURE. E2F3A KNOCKDOWN IN NAC DOES NOT ABOLISH DELTAFOSB INDUCTION BY COCAINE, A RESULT CONSISTENT WITH PREVIOUSLY PUBLISHED DATA SHOWING THAT SINGULAR KNOCKDOWN OF UPSTREAM REGULATORS OF DELTAFOSB IS INSUFFICIENT TO BLOCK COCAINE-INDUCED EXPRESSION. FINALLY, TO ELUCIDATE POTENTIAL COMBINATORIAL EPIGENETIC MECHANISMS INVOLVED IN E2F3A'S REGULATION OF FOSB, WE EXPLORE H3K4ME3 ENRICHMENT AT THE FOSB PROMOTER AND FIND THAT IT IS NOT ENHANCED BY E2F3A OVEREXPRESSION, SUGGESTING THAT IT MAY INSTEAD BE A PRE-EXISTING PERMISSIVE MARK ALLOWING FOR E2F3A TO INTERACT WITH FOSB. TOGETHER, THESE FINDINGS SUPPORT A ROLE FOR E2F3A AS A NOVEL, UPSTREAM REGULATOR OF THE ADDICTION-MEDIATING TRANSCRIPTION FACTOR DELTAFOSB IN NAC. 2019 2 786 34 CELL-TYPE-SPECIFIC EPIGENETIC EDITING AT THE FOSB GENE CONTROLS SUSCEPTIBILITY TO SOCIAL DEFEAT STRESS. CHRONIC SOCIAL DEFEAT STRESS REGULATES THE EXPRESSION OF FOSB IN THE NUCLEUS ACCUMBENS (NAC) TO PROMOTE THE CELL-TYPE-SPECIFIC ACCUMULATION OF DELTAFOSB IN THE TWO MEDIUM SPINY NEURON (MSN) SUBTYPES IN THIS REGION. DELTAFOSB IS SELECTIVELY INDUCED IN D1-MSNS IN THE NAC OF RESILIENT MICE, AND IN D2-MSNS OF SUSCEPTIBLE MICE. HOWEVER, LITTLE IS KNOWN ABOUT THE CONSEQUENCES OF SUCH SELECTIVE INDUCTION, PARTICULARLY IN D2-MSNS. THIS STUDY EXAMINED HOW CELL-TYPE-SPECIFIC CONTROL OF THE ENDOGENOUS FOSB GENE IN NAC REGULATES SUSCEPTIBILITY TO SOCIAL DEFEAT STRESS. HISTONE POST-TRANSLATIONAL MODIFICATIONS (HPTMS) WERE TARGETED SPECIFICALLY TO FOSB USING ENGINEERED ZINC-FINGER PROTEINS (ZFPS). FOSB-ZFPS WERE FUSED TO EITHER THE TRANSCRIPTIONAL REPRESSOR, G9A, WHICH PROMOTES HISTONE METHYLATION OR THE TRANSCRIPTIONAL ACTIVATOR, P65, WHICH PROMOTES HISTONE ACETYLATION. THESE ZFPS WERE EXPRESSED IN D1- VS D2-MSNS USING CRE-DEPENDENT VIRAL EXPRESSION IN THE NAC OF MICE TRANSGENIC FOR CRE RECOMBINASE IN THESE MSN SUBTYPES. WE FOUND THAT STRESS SUSCEPTIBILITY IS OPPOSITELY REGULATED BY THE SPECIFIC CELL TYPE AND HPTM TARGETED. WE REPORT THAT FOSB-TARGETED HISTONE ACETYLATION IN D2-MSNS OR HISTONE METHYLATION IN D1-MSNS PROMOTES A STRESS-SUSCEPTIBLE, DEPRESSIVE-LIKE PHENOTYPE, WHILE HISTONE METHYLATION IN D2-MSNS OR HISTONE ACETYLATION IN D1-MSNS INCREASES RESILIENCE TO SOCIAL STRESS AS QUANTIFIED BY SOCIAL INTERACTION BEHAVIOR AND SUCROSE PREFERENCE. THIS WORK PRESENTS THE FIRST DEMONSTRATION OF CELL- AND GENE-SPECIFIC TARGETING OF HISTONE MODIFICATIONS, WHICH MODEL NATURALLY OCCURRING TRANSCRIPTIONAL PHENOMENA THAT CONTROL SOCIAL DEFEAT STRESS BEHAVIOR. THIS EPIGENETIC-EDITING APPROACH, WHICH RECAPITULATES PHYSIOLOGICAL CHANGES IN GENE EXPRESSION, REVEALS CLEAR DIFFERENCES IN THE SOCIAL DEFEAT PHENOTYPE INDUCED BY FOSB GENE MANIPULATION IN MSN SUBTYPES. 2018 3 4499 33 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 4 195 29 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 5 5503 31 RGS9-2--CONTROLLED ADAPTATIONS IN THE STRIATUM DETERMINE THE ONSET OF ACTION AND EFFICACY OF ANTIDEPRESSANTS IN NEUROPATHIC PAIN STATES. THE STRIATAL PROTEIN REGULATOR OF G-PROTEIN SIGNALING 9-2 (RGS9-2) PLAYS A KEY MODULATORY ROLE IN OPIOID, MONOAMINE, AND OTHER G-PROTEIN-COUPLED RECEPTOR RESPONSES. HERE, WE USE THE MURINE SPARED-NERVE INJURY MODEL OF NEUROPATHIC PAIN TO INVESTIGATE THE MECHANISM BY WHICH RGS9-2 IN THE NUCLEUS ACCUMBENS (NAC), A BRAIN REGION INVOLVED IN MOOD, REWARD, AND MOTIVATION, MODULATES THE ACTIONS OF TRICYCLIC ANTIDEPRESSANTS (TCAS). PREVENTION OF RGS9-2 ACTION IN THE NAC INCREASES THE EFFICACY OF THE TCA DESIPRAMINE AND DRAMATICALLY ACCELERATES ITS ONSET OF ACTION. BY CONTROLLING THE ACTIVATION OF EFFECTOR MOLECULES BY G PROTEIN ALPHA AND BETAGAMMA SUBUNITS, RGS9-2 AFFECTS SEVERAL PROTEIN INTERACTIONS, PHOSPHOPROTEIN LEVELS, AND THE FUNCTION OF THE EPIGENETIC MODIFIER HISTONE DEACETYLASE 5, WHICH ARE IMPORTANT FOR TCA RESPONSIVENESS. FURTHERMORE, INFORMATION FROM RNA-SEQUENCING ANALYSIS REVEALS THAT RGS9-2 IN THE NAC AFFECTS THE EXPRESSION OF MANY GENES KNOWN TO BE INVOLVED IN NOCICEPTION, ANALGESIA, AND ANTIDEPRESSANT DRUG ACTIONS. OUR FINDINGS PROVIDE NOVEL INFORMATION ON NAC-SPECIFIC CELLULAR MECHANISMS THAT MEDIATE THE ACTIONS OF TCAS IN NEUROPATHIC PAIN STATES. 2015 6 5832 22 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 7 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 8 1706 37 DYNORPHIN/KOP AND NOCICEPTIN/NOP GENE EXPRESSION AND EPIGENETIC CHANGES BY COCAINE IN RAT STRIATUM AND NUCLEUS ACCUMBENS. COCAINE INDUCES NEUROCHEMICAL CHANGES OF ENDOGENOUS PRODYNORPHIN-KAPPA OPIOID RECEPTOR (PDYN-KOP) AND PRONOCICEPTIN/ORPHANINFQ-NOCICEPTIN RECEPTOR (PN/OFQ-NOP) SYSTEMS. BOTH SYSTEMS PLAY AN IMPORTANT ROLE IN REWARDING MECHANISMS AND ADDICTIVE STIMULUS PROCESSING BY MODULATING DRUG-INDUCED DOPAMINERGIC ACTIVATION IN THE MESOCORTICO-LIMBIC BRAIN AREAS. THEY ARE ALSO INVOLVED IN REGULATING STRESS MECHANISMS RELATED TO ADDICTION. THE AIM OF THIS STUDY WAS TO INVESTIGATE POSSIBLE CHANGES OF GENE EXPRESSION OF THE DYNORPHINERGIC AND NOCICEPTINERGIC SYSTEM COMPONENTS IN THE NUCLEUS ACCUMBENS (NA) AND IN MEDIAL AND LATERAL CAUDATE PUTAMEN (MCPU AND LCPU, RESPECTIVELY) OF RATS, FOLLOWING CHRONIC SUBCUTANEOUS INFUSION OF COCAINE. IN ADDITION, THE EPIGENETIC HISTONE MODIFICATIONS H3K4ME3 AND H3K27ME3 (AN ACTIVATING AND A REPRESSIVE MARKER, RESPECTIVELY) AT THE PROMOTER LEVEL OF THE PDYN, KOP, PN/OFQ AND NOP GENES WERE INVESTIGATED. RESULTS SHOWED THAT COCAINE INDUCED PDYN GENE EXPRESSION UP-REGULATION IN THE NA AND LCPU, AND ITS DOWN-REGULATION IN THE MCPU, WHEREAS KOP MRNA LEVELS WERE UNCHANGED. MOREOVER, COCAINE EXPOSURE DECREASED PN/OFQ GENE EXPRESSION IN THE NA AND LCPU, WHILE NOP MRNA LEVELS APPEARED SIGNIFICANTLY INCREASED IN THE NA AND DECREASED IN THE LCPU. SPECIFIC CHANGES OF THE H3K4ME3 AND H3K27ME3 LEVELS WERE FOUND AT PDYN, PN/OFQ, AND NOP GENE PROMOTER, CONSISTENT WITH THE OBSERVED GENE EXPRESSION ALTERATIONS. THE PRESENT FINDINGS CONTRIBUTE TO BETTER DEFINE THE ROLE OF ENDOGENOUS PDYN-KOP AND PN/OFQ-NOP SYSTEMS IN NEUROPLASTICITY MECHANISMS FOLLOWING CHRONIC COCAINE TREATMENT. THE EPIGENETIC HISTONE MODIFICATIONS UNDERLYING THE GENE EXPRESSION CHANGES LIKELY MEDIATE THE EFFECTS OF COCAINE ON TRANSCRIPTIONAL REGULATION OF SPECIFIC GENE PROMOTERS THAT RESULT IN LONG-LASTING DRUG-INDUCED PLASTICITY. 2014 9 984 35 CHRONIC PSYCHOLOGICAL STRESS ALTERS GENE EXPRESSION IN RAT COLON EPITHELIAL CELLS PROMOTING CHROMATIN REMODELING, BARRIER DYSFUNCTION AND INFLAMMATION. CHRONIC STRESS IS COMMONLY ASSOCIATED WITH ENHANCED ABDOMINAL PAIN (VISCERAL HYPERSENSITIVITY), BUT THE CELLULAR MECHANISMS UNDERLYING HOW CHRONIC STRESS INDUCES VISCERAL HYPERSENSITIVITY ARE POORLY UNDERSTOOD. IN THIS STUDY, WE EXAMINED CHANGES IN GENE EXPRESSION IN COLON EPITHELIAL CELLS FROM A RAT MODEL USING RNA-SEQUENCING TO EXAMINE STRESS-INDUCED CHANGES TO THE TRANSCRIPTOME. FOLLOWING CHRONIC STRESS, THE MOST SIGNIFICANTLY UP-REGULATED GENES INCLUDED ATG16L1, COQ10B, DCAF13, NAT2, PTBP2, RRAS2, SPINK4 AND DOWN-REGULATED GENES INCLUDING ABAT, CITED2, CNNM2, DAB2IP, PLEKHM1, SCD2, AND TAB2. THE PRIMARY ALTERED BIOLOGICAL PROCESSES REVEALED BY NETWORK ENRICHMENT ANALYSIS WERE INFLAMMATION/IMMUNE RESPONSE, TISSUE MORPHOGENESIS AND DEVELOPMENT, AND NUCLEOSOME/CHROMATIN ASSEMBLY. THE MOST SIGNIFICANTLY DOWN-REGULATED PROCESS WAS THE DIGESTIVE SYSTEM DEVELOPMENT/FUNCTION, WHEREAS THE MOST SIGNIFICANTLY UP-REGULATED PROCESSES WERE INFLAMMATORY RESPONSE, ORGANISMAL INJURY, AND CHROMATIN REMODELING MEDIATED BY H3K9 METHYLATION. FURTHERMORE, A SUBPOPULATION OF STRESSED RATS DEMONSTRATED VERY SIGNIFICANTLY ALTERED GENE EXPRESSION AND TRANSCRIPT ISOFORMS, ENRICHED FOR THE DIFFERENTIAL EXPRESSION OF GENES INVOLVED IN THE INFLAMMATORY RESPONSE, INCLUDING UPREGULATION OF CYTOKINE AND CHEMOKINE RECEPTOR GENE EXPRESSION COUPLED WITH DOWNREGULATION OF EPITHELIAL ADHERENS AND TIGHT JUNCTION MRNAS. IN SUMMARY, THESE FINDINGS SUPPORT THAT CHRONIC STRESS IS ASSOCIATED WITH INCREASED LEVELS OF CYTOKINES AND CHEMOKINES, THEIR DOWNSTREAM SIGNALING PATHWAYS COUPLED TO DYSREGULATION OF INTESTINAL CELL DEVELOPMENT AND FUNCTION. EPIGENETIC REGULATION OF CHROMATIN REMODELING LIKELY PLAYS A PROMINENT ROLE IN THIS PROCESS. RESULTS ALSO SUGGEST THAT SUPER ENHANCERS PLAY A PRIMARY ROLE IN CHRONIC STRESS-ASSOCIATED INTESTINAL BARRIER DYSFUNCTION. 2022 10 2246 22 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 11 856 24 CHROMATIN ACCESSIBILITY MAPPING OF THE STRIATUM IDENTIFIES TYROSINE KINASE FYN AS A THERAPEUTIC TARGET FOR HEROIN USE DISORDER. THE CURRENT OPIOID EPIDEMIC NECESSITATES A BETTER UNDERSTANDING OF HUMAN ADDICTION NEUROBIOLOGY TO DEVELOP EFFICACIOUS TREATMENT APPROACHES. HERE, WE PERFORM GENOME-WIDE ASSESSMENT OF CHROMATIN ACCESSIBILITY OF THE HUMAN STRIATUM IN HEROIN USERS AND MATCHED CONTROLS. OUR STUDY REVEALS DISTINCT NEURONAL AND NON-NEURONAL EPIGENETIC SIGNATURES, AND IDENTIFIES A LOCUS IN THE PROXIMITY OF THE GENE ENCODING TYROSINE KINASE FYN AS THE MOST AFFECTED REGION IN NEURONS. FYN EXPRESSION, KINASE ACTIVITY AND THE PHOSPHORYLATION OF ITS TARGET TAU ARE INCREASED BY HEROIN USE IN THE POST-MORTEM HUMAN STRIATUM, AS WELL AS IN RATS TRAINED TO SELF-ADMINISTER HEROIN AND PRIMARY STRIATAL NEURONS TREATED WITH CHRONIC MORPHINE IN VITRO. PHARMACOLOGICAL OR GENETIC MANIPULATION OF FYN ACTIVITY SIGNIFICANTLY ATTENUATES HEROIN SELF-ADMINISTRATION AND RESPONDING FOR DRUG-PAIRED CUES IN RODENTS. OUR FINDINGS SUGGEST THAT STRIATAL FYN IS AN IMPORTANT DRIVER OF HEROIN-RELATED NEURODEGENERATIVE-LIKE PATHOLOGY AND DRUG-TAKING BEHAVIOR, MAKING FYN A PROMISING THERAPEUTIC TARGET FOR HEROIN USE DISORDER. 2020 12 4861 24 ORGANIC ANION TRANSPORTER 1 IS AN HDAC4-REGULATED MEDIATOR OF NOCICEPTIVE HYPERSENSITIVITY IN MICE. PERSISTENT PAIN IS SUSTAINED BY MALADAPTIVE CHANGES IN GENE TRANSCRIPTION RESULTING IN ALTERED FUNCTION OF THE RELEVANT CIRCUITS; THERAPIES ARE STILL UNSATISFACTORY. THE EPIGENETIC MECHANISMS AND AFFECTED GENES LINKING NOCICEPTIVE ACTIVITY TO TRANSCRIPTIONAL CHANGES AND PATHOLOGICAL SENSITIVITY ARE UNCLEAR. HERE, WE FOUND THAT, AMONG SEVERAL HISTONE DEACETYLASES (HDACS), SYNAPTIC ACTIVITY SPECIFICALLY AFFECTS HDAC4 IN MURINE SPINAL CORD DORSAL HORN NEURONS. NOXIOUS STIMULI THAT INDUCE LONG-LASTING INFLAMMATORY HYPERSENSITIVITY CAUSE NUCLEAR EXPORT AND INACTIVATION OF HDAC4. THE DEVELOPMENT OF INFLAMMATION-ASSOCIATED MECHANICAL HYPERSENSITIVITY, BUT NEITHER ACUTE NOR BASAL SENSITIVITY, IS IMPAIRED BY THE EXPRESSION OF A CONSTITUTIVELY NUCLEAR LOCALIZED HDAC4 MUTANT. NEXT GENERATION RNA-SEQUENCING REVEALED AN HDAC4-REGULATED GENE PROGRAM COMPRISING MEDIATORS OF SENSITIZATION INCLUDING THE ORGANIC ANION TRANSPORTER OAT1, KNOWN FOR ITS RENAL TRANSPORT FUNCTION. USING PHARMACOLOGICAL AND MOLECULAR TOOLS TO MODULATE OAT1 ACTIVITY OR EXPRESSION, WE CAUSALLY LINK OAT1 TO PERSISTENT INFLAMMATORY HYPERSENSITIVITY IN MICE. THUS, HDAC4 IS A KEY EPIGENETIC REGULATOR THAT TRANSLATES NOCICEPTIVE ACTIVITY INTO SENSITIZATION BY REGULATING OAT1, WHICH IS A POTENTIAL TARGET FOR PAIN-RELIEVING THERAPIES. 2022 13 612 26 BINDING OF TFIIIC TO SINE ELEMENTS CONTROLS THE RELOCATION OF ACTIVITY-DEPENDENT NEURONAL GENES TO TRANSCRIPTION FACTORIES. IN NEURONS, THE TIMELY AND ACCURATE EXPRESSION OF GENES IN RESPONSE TO SYNAPTIC ACTIVITY RELIES ON THE INTERPLAY BETWEEN EPIGENETIC MODIFICATIONS OF HISTONES, RECRUITMENT OF REGULATORY PROTEINS TO CHROMATIN AND CHANGES TO NUCLEAR STRUCTURE. TO IDENTIFY GENES AND REGULATORY ELEMENTS RESPONSIVE TO SYNAPTIC ACTIVATION IN VIVO, WE PERFORMED A GENOME-WIDE CHIPSEQ ANALYSIS OF ACETYLATED HISTONE H3 USING SOMATOSENSORY CORTEX OF MICE EXPOSED TO NOVEL ENRICHED ENVIRONMENTAL (NEE) CONDITIONS. WE DISCOVERED THAT SHORT INTERSPERSED ELEMENTS (SINES) LOCATED DISTAL TO PROMOTERS OF ACTIVITY-DEPENDENT GENES BECAME ACETYLATED FOLLOWING EXPOSURE TO NEE AND WERE BOUND BY THE GENERAL TRANSCRIPTION FACTOR TFIIIC. IMPORTANTLY, UNDER DEPOLARIZING CONDITIONS, INDUCIBLE GENES RELOCATED TO TRANSCRIPTION FACTORIES (TFS), AND THIS EVENT WAS CONTROLLED BY TFIIIC. SILENCING OF THE TFIIIC SUBUNIT GTF3C5 IN NON-STIMULATED NEURONS INDUCED UNCONTROLLED RELOCATION TO TFS AND TRANSCRIPTION OF ACTIVITY-DEPENDENT GENES. REMARKABLY, IN CORTICAL NEURONS, SILENCING OF GTF3C5 MIMICKED THE EFFECTS OF CHRONIC DEPOLARIZATION, INDUCING A DRAMATIC INCREASE OF BOTH DENDRITIC LENGTH AND BRANCHING. THESE FINDINGS REVEAL A NOVEL AND ESSENTIAL REGULATORY FUNCTION OF BOTH SINES AND TFIIIC IN MEDIATING GENE RELOCATION AND TRANSCRIPTION. THEY ALSO SUGGEST THAT TFIIIC MAY REGULATE THE REARRANGEMENT OF NUCLEAR ARCHITECTURE, ALLOWING THE COORDINATED EXPRESSION OF ACTIVITY-DEPENDENT NEURONAL GENES. 2013 14 5838 35 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 15 2886 26 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 16 3002 27 GENETIC, EPIGENETIC AND POSTTRANSCRIPTIONAL MECHANISMS FOR TREATMENT OF MAJOR DEPRESSION: THE 5-HT1A RECEPTOR GENE AS A PARADIGM. MAJOR DEPRESSION AND ANXIETY ARE HIGHLY PREVALENT AND INVOLVE CHRONIC DYSREGULATION OF SEROTONIN, BUT THEY REMAIN POORLY UNDERSTOOD. HERE, WE REVIEW NOVEL TRANSCRIPTIONAL (GENETIC, EPIGENETIC) AND POSTTRANSCRIPTIONAL (MICRORNA, ALTERNATIVE SPLICING) MECHANISMS IMPLICATED IN MENTAL ILLNESS, FOCUSING ON A KEY SEROTONIN-RELATED REGULATOR, THE SEROTONIN 1A (5-HT1A) RECEPTOR. FUNCTIONAL SINGLE-NUCLEOTIDE POLYMORPHISMS AND STRESS-INDUCED DNA METHYLATION OF THE 5-HT1A PROMOTER CONVERGE TO DIFFERENTIALLY ALTER PRE- AND POSTSYNAPTIC 5-HT1A RECEPTOR EXPRESSION ASSOCIATED WITH MAJOR DEPRESSION AND REDUCED THERAPEUTIC RESPONSE TO SEROTONERGIC ANTIDEPRESSANTS. MAJOR DEPRESSION IS ALSO ASSOCIATED WITH ALTERED LEVELS OF SPLICE FACTORS AND MICRORNA, POSTTRANSCRIPTIONAL MECHANISMS THAT REGULATE RNA STABILITY. THE HUMAN 5-HT1A 3'-UNTRANSLATED REGION IS ALTERNATIVELY SPLICED, REMOVING MICRORNA SITES AND INCREASING 5-HT1A EXPRESSION, WHICH IS REDUCED IN MAJOR DEPRESSION AND MAY BE GENOTYPE-DEPENDENT. THUS, THE 5-HT1A RECEPTOR GENE ILLUSTRATES THE CONVERGENCE OF GENETIC, EPIGENETIC AND POSTTRANSCRIPTIONAL MECHANISMS IN GENE EXPRESSION, NEURODEVELOPMENT AND NEUROPLASTICITY, AND MAJOR DEPRESSION. UNDERSTANDING GENE REGULATORY MECHANISMS COULD ENHANCE THE DETECTION, CATEGORIZATION AND PERSONALIZED TREATMENT OF MAJOR DEPRESSION. 2019 17 889 32 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 18 5713 33 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 19 433 26 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 20 1330 43 DEPRESSIVE-LIKE BEHAVIORS ARE REGULATED BY NOX1/NADPH OXIDASE BY REDOX MODIFICATION OF NMDA RECEPTOR 1. INVOLVEMENT OF REACTIVE OXYGEN SPECIES (ROS) HAS BEEN SUGGESTED IN THE DEVELOPMENT OF PSYCHIATRIC DISORDERS. NOX1 IS A NONPHAGOCYTIC FORM OF NADPH OXIDASE WHOSE EXPRESSION IN THE NERVOUS SYSTEM IS NEGLIGIBLE COMPARED WITH OTHER NOX ISOFORMS. HOWEVER, NOX1-DERIVED ROS INCREASE INFLAMMATORY PAIN AND TOLERANCE TO OPIOID ANALGESIA. TO CLARIFY THE ROLE OF NOX1 IN THE BRAIN, WE EXAMINED DEPRESSIVE-LIKE BEHAVIORS IN MICE DEFICIENT IN NOX1 (NOX1(-/Y)). DEPRESSIVE-LIKE BEHAVIORS INDUCED BY CHRONIC SOCIAL DEFEAT STRESS OR ADMINISTRATION OF CORTICOSTERONE (CORT) WERE SIGNIFICANTLY AMELIORATED IN NOX1(-/Y) GENERATION OF ROS WAS SIGNIFICANTLY ELEVATED IN THE PREFRONTAL CORTEX (PFC) OF MICE ADMINISTRATED WITH CORT, WHILE NOX1 MRNA WAS UPREGULATED ONLY IN THE VENTRAL TEGMENTAL AREA (VTA) AMONG BRAIN AREAS RESPONSIBLE FOR EMOTIONAL BEHAVIORS. DELIVERY OF MIRNA AGAINST NOX1 TO VTA RESTORED CORT-INDUCED DEPRESSIVE-LIKE BEHAVIORS IN WILD-TYPE (WT) LITTERMATES. ADMINISTRATION OF CORT TO WT, BUT NOT TO NOX1(-/Y), SIGNIFICANTLY REDUCED TRANSCRIPT LEVELS OF BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF), WITH A CONCOMITANT INCREASE IN DNA METHYLATION OF THE PROMOTER REGIONS IN BDNF DELIVERY OF MIRNA AGAINST NOX1 TO VTA RESTORED THE LEVEL OF BDNF MRNA IN WT PFC. REDOX PROTEOME ANALYSES DEMONSTRATED THAT NMDA RECEPTOR 1 (NR1) WAS AMONG THE MOLECULES REDOX REGULATED BY NOX1. IN CULTURED CORTICAL NEURONS, HYDROGEN PEROXIDE SIGNIFICANTLY SUPPRESSED NMDA-INDUCED UPREGULATION OF BDNF TRANSCRIPTS IN NR1-EXPRESSING CELLS BUT NOT IN CELLS HARBORING MUTANT NR1 (C744A). TOGETHER, THESE FINDINGS SUGGEST A KEY ROLE OF NOX1 IN DEPRESSIVE-LIKE BEHAVIORS THROUGH NR1-MEDIATED EPIGENETIC MODIFICATION OF BDNF IN THE MESOPREFRONTAL PROJECTION.SIGNIFICANCE STATEMENT NADPH OXIDASE IS A SOURCE OF REACTIVE OXYGEN SPECIES (ROS) THAT HAVE BEEN IMPLICATED IN THE PATHOGENESIS OF VARIOUS NEUROLOGICAL DISORDERS. WE PRESENTLY SHOWED THE INVOLVEMENT OF A NONPHAGOCYTIC TYPE OF NADPH OXIDASE, NOX1, IN MAJOR DEPRESSIVE DISORDERS, INCLUDING BEHAVIORAL, BIOCHEMICAL, AND ANATOMICAL CHANGES IN MICE. THE OXIDATION OF NR1 BY NOX1-DERIVED ROS WAS DEMONSTRATED IN PREFRONTAL CORTEX (PFC), WHICH MAY BE CAUSALLY LINKED TO THE DOWNREGULATION OF BDNF, PROMOTING DEPRESSIVE-LIKE BEHAVIORS. GIVEN THAT NOX1 IS UPREGULATED ONLY IN VTA BUT NOT IN PFC, MESOCORTICAL PROJECTIONS APPEAR TO PLAY A CRUCIAL ROLE IN NOX1-DEPENDENT DEPRESSIVE-LIKE BEHAVIORS. OUR STUDY IS THE FIRST TO PRESENT THE POTENTIAL MOLECULAR MECHANISM UNDERLYING THE DEVELOPMENT OF MAJOR DEPRESSION THROUGH THE NOX1-INDUCED OXIDATION OF NR1 AND EPIGENETIC MODIFICATION OF BDNF. 2017