1 5443 161 REPEATED METHAMPHETAMINE AND MODAFINIL INDUCE DIFFERENTIAL COGNITIVE EFFECTS AND SPECIFIC HISTONE ACETYLATION AND DNA METHYLATION PROFILES IN THE MOUSE MEDIAL PREFRONTAL CORTEX. METHAMPHETAMINE (METH) AND MODAFINIL ARE PSYCHOSTIMULANTS WITH DIFFERENT LONG-TERM COGNITIVE PROFILES: METH IS ADDICTIVE AND LEADS TO COGNITIVE DECLINE, WHEREAS MODAFINIL HAS LITTLE ABUSE LIABILITY AND IS A COGNITIVE ENHANCER. INCREASING EVIDENCE IMPLICATES EPIGENETIC MECHANISMS OF GENE REGULATION BEHIND THE LASTING CHANGES THAT DRUGS OF ABUSE AND OTHER PSYCHOTROPIC COMPOUNDS INDUCE IN THE BRAIN, LIKE THE CONTROL OF GENE EXPRESSION BY HISTONES 3 AND 4 TAILS ACETYLATION (H3AC AND H4AC) AND DNA CYTOSINE METHYLATION (5-MC). MICE WERE TREATED WITH A SEVEN-DAY REPEATED METH, MODAFINIL OR VEHICLE PROTOCOL AND EVALUATED IN THE NOVEL OBJECT RECOGNITION (NOR) TEST OR SACRIFICED 4DAYS AFTER LAST INJECTION FOR MOLECULAR ASSAYS. WE EVALUATED TOTAL H3AC, H4AC AND 5-MC LEVELS IN THE MEDIAL PREFRONTAL CORTEX (MPFC), H3AC AND H4AC PROMOTOR ENRICHMENT (CHIP) AND MRNA EXPRESSION (RT-PCR) OF NEUROTRANSMITTER SYSTEMS INVOLVED IN AROUSAL, WAKEFULNESS AND COGNITIVE CONTROL, LIKE DOPAMINERGIC (DRD1 AND DRD2), ALPHA-ADRENERGIC (ADRA1A AND ADRA1B), OREXINERGIC (HCRTR1 AND HCRTR2), HISTAMINERGIC (HRH1 AND HRH3) AND GLUTAMATERGIC (AMPA GRIA1 AND NMDA GRIN1) RECEPTORS. REPEATED METH AND MODAFINIL TREATMENT ELICITED DIFFERENT COGNITIVE OUTCOMES IN THE NOR TEST, WHERE MODAFINIL-TREATED MICE PERFORMED AS CONTROLS AND METH-TREATED MICE SHOWED IMPAIRED RECOGNITION MEMORY. METH-TREATED MICE ALSO SHOWED I) DECREASED LEVELS OF TOTAL H3AC AND H4AC, AND INCREASED LEVELS OF 5-MC, II) DECREASED H3AC ENRICHMENT AT PROMOTERS OF DRD2, HCRTR1/2, HRH1 AND GRIN1, AND INCREASED H4AC ENRICHMENT AT DRD1, HRH1 AND GRIN1, III) INCREASED MRNA OF DRD1A, GRIN1 AND GRIA1. MODAFINIL-TREATED MICE SHARED NONE OF THESE EFFECTS AND SHOWED INCREASED H3AC ENRICHMENT AND MRNA EXPRESSION AT ADRA1B. MODAFINIL AND METH SHOWED SIMILAR EFFECTS LINKED TO DECREASED H3AC IN HRH3, INCREASED H4AC IN HCRTR1, AND DECREASED MRNA EXPRESSION OF HCRTR2. THE SPECIFIC METH-INDUCED EPIGENETIC AND TRANSCRIPTIONAL CHANGES DESCRIBED HERE MAY BE RELATED TO THE LONG-TERM COGNITIVE DECLINE EFFECTS OF THE DRUG AND ITS DETRIMENTAL EFFECTS ON MPFC FUNCTION. THE LACK OF SIMILAR EPIGENETIC EFFECTS OF CHRONIC MODAFINIL ADMINISTRATION SUPPORTS THIS NOTION. 2018 2 6095 85 THE EFFECTS OF SINGLE-DOSE INJECTIONS OF MODAFINIL AND METHAMPHETAMINE ON EPIGENETIC AND FUNCTIONAL MARKERS IN THE MOUSE MEDIAL PREFRONTAL CORTEX: POTENTIAL ROLE OF DOPAMINE RECEPTORS. METH USE CAUSES NEUROADAPTATIONS THAT NEGATIVELY IMPACT THE PREFRONTAL CORTEX (PFC) LEADING TO ADDICTION AND ASSOCIATED COGNITIVE DECLINE IN ANIMALS AND HUMANS. IN CONTRAST, MODAFINIL ENHANCES COGNITION BY INCREASING PFC FUNCTION. ACCUMULATED EVIDENCE INDICATES THAT PSYCHOSTIMULANT DRUGS, INCLUDING MODAFINIL AND METH, REGULATE GENE EXPRESSION VIA EPIGENETIC MODIFICATIONS. IN THIS STUDY, WE MEASURED THE EFFECTS OF SINGLE-DOSE INJECTIONS OF MODAFINIL AND METH ON THE PROTEIN LEVELS OF ACETYLATED HISTONE H3 (H3AC) AND H4AC, DEACETYLASES HDAC1 AND HDAC2, AND OF THE NMDA SUBUNIT GLUN1 IN THE MEDIAL PFC (MPFC) OF MICE EUTHANIZED 1 H AFTER DRUG ADMINISTRATION. TO TEST IF DOPAMINE (DA) RECEPTORS (DRS) PARTICIPATE IN THE BIOCHEMICAL EFFECTS OF THE TWO DRUGS, WE INJECTED THE D1RS ANTAGONIST, SCH23390, OR THE D2RS ANTAGONIST, RACLOPRIDE, 30 MIN BEFORE ADMINISTRATION OF METH AND MODAFINIL. WE EVALUATED EACH DRUG EFFECT ON GLUTAMATE SYNAPTIC TRANSMISSION IN D1R-EXPRESSING LAYER V PYRAMIDAL NEURONS. WE ALSO MEASURED THE ENRICHMENT OF H3AC AND H4AC AT THE PROMOTERS OF SEVERAL GENES INCLUDING DA, NE, OREXIN, HISTAMINE, AND GLUTAMATE RECEPTORS, AND THEIR MRNA EXPRESSION, SINCE THEY ARE RESPONSIVE TO CHRONIC MODAFINIL AND METH TREATMENT. ACUTE MODAFINIL AND METH INJECTIONS CAUSED SIMILAR EFFECTS ON TOTAL HISTONE ACETYLATION, INCREASING H3AC AND DECREASING H4AC, AND THEY ALSO INCREASED HDAC1, HDAC2 AND GLUN1 PROTEIN LEVELS IN THE MOUSE MPFC. IN ADDITION, THE EFFECTS OF THE DRUGS WERE PREVENTED BY PRE-TREATMENT WITH D1RS AND D2RS ANTAGONISTS. SPECIFICALLY, THE CHANGES IN H4AC, HDAC2, AND GLUN1 WERE RESPONSIVE TO SCH23390, WHEREAS THOSE OF H3AC AND GLUN1 WERE RESPONSIVE TO RACLOPRIDE. WHOLE-CELL PATCH CLAMP IN TRANSGENIC BAC-DRD1A-TDTOMATO MICE SHOWED THAT METH, BUT NOT MODAFINIL, INDUCED PAIRED-PULSE FACILITATION OF EPSCS, SUGGESTING REDUCED PRESYNAPTIC PROBABILITY OF GLUTAMATE RELEASE ONTO LAYER V PYRAMIDAL NEURONS. ANALYSIS OF HISTONE 3/4 ENRICHMENT AT SPECIFIC PROMOTERS REVEALED: I) DISTINCT EFFECTS OF THE DRUGS ON HISTONE 3 ACETYLATION, WITH MODAFINIL INCREASING H3AC AT DRD1 AND ADRA1B PROMOTERS, BUT METH INCREASING H3AC AT ADRA1A; II) DISTINCT EFFECTS ON HISTONE 4 ACETYLATION ENRICHMENT, WITH MODAFINIL INCREASING H4AC AT THE DRD2 PROMOTER AND DECREASING IT AT HRH1, BUT METH INCREASING H4AC AT DRD1; III) COMPARABLE EFFECTS OF BOTH PSYCHOSTIMULANTS, INCREASING H3AC AT DRD2, HCRTR1, AND HRH1 PROMOTERS, DECREASING H3AC AT HRH3, INCREASING H4AC AT HCRTR1, AND DECREASING H4AC AT HCRTR2, HRH3, AND GRIN1 PROMOTERS. INTERESTINGLY, ONLY METH ALTERED MRNA LEVELS OF GENES WITH ALTERED HISTONE ACETYLATION STATUS, INDUCING INCREASED EXPRESSION OF DRD1A, ADRA1A, HCRTR1, AND HRH1, AND DECREASING GRIN1. OUR STUDY SUGGESTS THAT ALTHOUGH ACUTE METH AND MODAFINIL CAN BOTH INCREASE DA NEUROTRANSMISSION IN THE MPFC, THERE ARE SIMILAR AND CONTRASTING EPIGENETIC AND TRANSCRIPTIONAL CONSEQUENCES THAT MAY ACCOUNT FOR THEIR DIVERGENT CLINICAL EFFECTS. 2019 3 3201 38 HDAC2 IN PRIMARY SENSORY NEURONS CONSTITUTIVELY RESTRAINS CHRONIC PAIN BY REPRESSING ALPHA2DELTA-1 EXPRESSION AND ASSOCIATED NMDA RECEPTOR ACTIVITY. ALPHA2DELTA-1 (ENCODED BY THE CACNA2D1 GENE) IS A NEWLY DISCOVERED NMDA RECEPTOR-INTERACTING PROTEIN AND IS THE THERAPEUTIC TARGET OF GABAPENTINOIDS (E.G., GABAPENTIN AND PREGABALIN) FREQUENTLY USED FOR TREATING PATIENTS WITH NEUROPATHIC PAIN. NERVE INJURY CAUSES SUSTAINED ALPHA2DELTA-1 UPREGULATION IN THE DORSAL ROOT GANGLION (DRG), WHICH PROMOTES NMDA RECEPTOR SYNAPTIC TRAFFICKING AND ACTIVATION IN THE SPINAL DORSAL HORN, A HALLMARK OF CHRONIC NEUROPATHIC PAIN. HOWEVER, LITTLE IS KNOWN ABOUT HOW NERVE INJURY INITIATES AND MAINTAINS THE HIGH EXPRESSION LEVEL OF ALPHA2DELTA-1 TO SUSTAIN CHRONIC PAIN. HERE, WE SHOW THAT NERVE INJURY CAUSED HISTONE HYPERACETYLATION AND DIMINISHED ENRICHMENT OF HISTONE DEACETYLASE-2 (HDAC2), BUT NOT HDAC3, AT THE CACNA2D1 PROMOTER IN THE DRG. STRIKINGLY, HDAC2 KNOCKDOWN OR CONDITIONAL KNOCKOUT IN DRG NEURONS IN MALE AND FEMALE MICE CONSISTENTLY INDUCED LONG-LASTING MECHANICAL PAIN HYPERSENSITIVITY, WHICH WAS READILY REVERSED BY BLOCKING NMDA RECEPTORS, INHIBITING ALPHA2DELTA-1 WITH GABAPENTIN OR DISRUPTING THE ALPHA2DELTA-1-NMDA RECEPTOR INTERACTION AT THE SPINAL CORD LEVEL. HDAC2 DELETION IN DRG NEURONS INCREASED HISTONE ACETYLATION LEVELS AT THE CACNA2D1 PROMOTER, UPREGULATED ALPHA2DELTA-1 IN THE DRG, AND POTENTIATED ALPHA2DELTA-1-DEPENDENT NMDA RECEPTOR ACTIVITY AT PRIMARY AFFERENT CENTRAL TERMINALS IN THE SPINAL DORSAL HORN. CORRESPONDINGLY, HDAC2 KNOCKDOWN-INDUCED PAIN HYPERSENSITIVITY WAS BLUNTED IN CACNA2D1 KNOCKOUT MICE. THUS, OUR FINDINGS REVEAL THAT HDAC2 FUNCTIONS AS A PIVOTAL TRANSCRIPTIONAL REPRESSOR OF NEUROPATHIC PAIN VIA CONSTITUTIVELY SUPPRESSING ALPHA2DELTA-1 EXPRESSION AND ENSUING PRESYNAPTIC NMDA RECEPTOR ACTIVITY IN THE SPINAL CORD. HDAC2 ENRICHMENT LEVELS AT THE CACNA2D1 PROMOTER IN DRG NEURONS CONSTITUTE A UNIQUE EPIGENETIC MECHANISM THAT GOVERNS ACUTE-TO-CHRONIC PAIN TRANSITION.SIGNIFICANCE STATEMENT EXCESS ALPHA2DELTA-1 PROTEINS PRODUCED AFTER NERVE INJURY DIRECTLY INTERACT WITH GLUTAMATE NMDA RECEPTORS TO POTENTIATE SYNAPTIC NMDA RECEPTOR ACTIVITY IN THE SPINAL CORD, A PROMINENT MECHANISM OF NERVE PAIN. BECAUSE ALPHA2DELTA-1 UPREGULATION AFTER NERVE INJURY IS LONG LASTING, GABAPENTINOIDS RELIEVE PAIN SYMPTOMS ONLY TEMPORARILY. OUR STUDY DEMONSTRATES FOR THE FIRST TIME THE UNEXPECTED ROLE OF INTRINSIC HDAC2 ACTIVITY AT THE ALPHA2DELTA-1 GENE PROMOTER IN LIMITING ALPHA2DELTA-1 GENE TRANSCRIPTION, NMDA RECEPTOR-DEPENDENT SYNAPTIC PLASTICITY, AND CHRONIC PAIN DEVELOPMENT AFTER NERVE INJURY. THESE FINDINGS CHALLENGE THE PREVAILING VIEW ABOUT THE ROLE OF GENERAL HDAC ACTIVITY IN PROMOTING CHRONIC PAIN. RESTORING THE REPRESSIVE HDAC2 FUNCTION AND/OR REDUCING HISTONE ACETYLATION AT THE ALPHA2DELTA-1 GENE PROMOTER IN PRIMARY SENSORY NEURONS COULD LEAD TO LONG-LASTING RELIEF OF NERVE PAIN. 2022 4 4212 40 METHAMPHETAMINE DOWNREGULATES STRIATAL GLUTAMATE RECEPTORS VIA DIVERSE EPIGENETIC MECHANISMS. BACKGROUND: CHRONIC METHAMPHETAMINE (METH) EXPOSURE CAUSES NEUROADAPTATIONS AT GLUTAMATERGIC SYNAPSES. METHODS: TO IDENTIFY THE METH-INDUCED EPIGENETIC UNDERPINNINGS OF THESE NEUROADAPTATIONS, WE INJECTED INCREASING METH DOSES TO RATS FOR 2 WEEKS AND MEASURED STRIATAL GLUTAMATE RECEPTOR EXPRESSION. WE THEN QUANTIFIED THE EFFECTS OF METH EXPOSURE ON HISTONE ACETYLATION. WE ALSO MEASURED METH-INDUCED CHANGES IN DNA METHYLATION AND DNA HYDROXYMETHYLATION. RESULTS: CHRONIC METH DECREASED TRANSCRIPT AND PROTEIN EXPRESSION OF GLUA1 AND GLUA2 ALPHA-AMINO-3-HYDROXY-5-METHYL-4-ISOXAZOLE PROPIONIC ACID RECEPTOR (AMPAR) AND GLUN1 N-METHYL-D-ASPARTATE RECEPTOR SUBUNITS. THESE CHANGES WERE ASSOCIATED WITH ALTERED ELECTROPHYSIOLOGICAL GLUTAMATERGIC RESPONSES IN STRIATAL NEURONS. CHROMATIN IMMUNOPRECIPITATION-POLYMERASE CHAIN REACTION REVEALED THAT METH DECREASED ENRICHMENT OF ACETYLATED HISTONE H4 ON GLUA1, GLUA2, AND GLUN1 PROMOTERS. METHAMPHETAMINE EXPOSURE ALSO INCREASED REPRESSOR ELEMENT-1 SILENCING TRANSCRIPTION FACTOR (REST) COREPRESSOR 1, METHYLATED CPG BINDING PROTEIN 2, AND HISTONE DEACETYLASE 2 ENRICHMENT, BUT NOT OF SIRTUIN 1 OR SIRTUIN 2, ONTO GLUA1 AND GLUA2 GENE SEQUENCES. MOREOVER, METH CAUSED INTERACTIONS OF REST COREPRESSOR 1 AND METHYLATED CPG BINDING PROTEIN 2 WITH HISTONE DEACETYLASE 2 AND OF REST WITH HISTONE DEACETYLASE 1. SURPRISINGLY, METHYLATED DNA IMMUNOPRECIPITATION AND HYDROXYMETHYLATED DNA IMMUNOPRECIPITATION-POLYMERASE CHAIN REACTION REVEALED METH-INDUCED DECREASED ENRICHMENT OF 5-METHYLCYTOSINE AND 5-HYDROXYMETHYLCYTOSINE AT GLUA1 AND GLUA2 PROMOTER SEQUENCES. IMPORTANTLY, THE HISTONE DEACETYLASE INHIBITOR, VALPROIC ACID, BLOCKED METH-INDUCED DECREASED EXPRESSION OF AMPAR AND N-METHYL-D-ASPARTATE RECEPTOR SUBUNITS. FINALLY, VALPROIC ACID ALSO ATTENUATED METH-INDUCED DECREASE H4K16AC RECRUITMENT ON AMPAR GENE SEQUENCES. CONCLUSIONS: THESE OBSERVATIONS SUGGEST THAT HISTONE H4 HYPOACETYLATION MAY BE THE MAIN DETERMINANT OF METH-INDUCED DECREASED STRIATAL GLUTAMATE RECEPTOR EXPRESSION. 2014 5 3331 41 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 6 5657 34 SEX-DEPENDENT PRONOCICEPTIVE ROLE OF SPINAL ALPHA(5) -GABA(A) RECEPTOR AND ITS EPIGENETIC REGULATION IN NEUROPATHIC RODENTS. EXTRASYNAPTIC ALPHA(5) -SUBUNIT CONTAINING GABA(A) (ALPHA(5) -GABA(A) ) RECEPTORS PARTICIPATE IN CHRONIC PAIN. PREVIOUSLY, WE REPORTED A SEX DIFFERENCE IN THE ACTION OF ALPHA(5) -GABA(A) RECEPTORS IN DYSFUNCTIONAL PAIN. HOWEVER, THE UNDERLYING MECHANISMS REMAIN UNKNOWN. THE AIM OF THIS STUDY WAS TO EXAMINE THIS SEXUAL DIMORPHISM IN NEUROPATHIC RODENTS AND THE MECHANISMS INVOLVED. FEMALE AND MALE WISTAR RATS OR ICR MICE WERE SUBJECTED TO NERVE INJURY FOLLOWED BY ALPHA(5) -GABA(A) RECEPTOR INVERSE AGONIST INTRATHECAL ADMINISTRATION, L-655,708. THE DRUG PRODUCED AN ANTIALLODYNIC EFFECT IN NERVE-INJURED FEMALE RATS AND MICE, AND A LOWER EFFECT IN MALES. WE HYPOTHESIZED THAT CHANGES IN ALPHA(5) -GABA(A) RECEPTOR, PROBABLY INFLUENCED BY HORMONAL AND EPIGENETIC STATUS, MIGHT UNDERLIE THIS SEX DIFFERENCE. THUS, WE PERFORMED QPCR AND WESTERN BLOT. NERVE INJURY INCREASED ALPHA(5) -GABA(A) MRNA AND PROTEIN IN FEMALE DORSAL ROOT GANGLIA (DRG) AND DECREASED THEM IN DRG AND SPINAL CORD OF MALES. TO INVESTIGATE THE HORMONAL INFLUENCE OVER ALPHA(5) -GABA(A) RECEPTOR ACTIONS, WE PERFORMED NERVE INJURY TO OVARIECTOMIZED RATS AND RECONSTITUTED THEM WITH 17BETA-ESTRADIOL (E2). OVARIECTOMY ABROGATED L-655,708 ANTIALLODYNIC EFFECT AND E2 RESTORED IT. OVARIECTOMY DECREASED ALPHA(5) -GABA(A) RECEPTOR AND ESTROGEN RECEPTOR ALPHA PROTEIN IN DRG OF NEUROPATHIC FEMALE RATS, WHILE E2 ENHANCED THEM. SINCE DNA METHYLATION MIGHT CONTRIBUTE TO ALPHA(5) -GABA(A) RECEPTOR DOWN-REGULATION IN MALES, WE EXAMINED CPG ISLAND DNA METHYLATION OF ALPHA(5) -GABA(A) RECEPTOR CODING GENE THROUGH PYROSEQUENCING. NERVE INJURY INCREASED METHYLATION IN MALE, BUT NOT FEMALE RATS. PHARMACOLOGICAL INHIBITION OF DNA METHYLTRANSFERASES INCREASED ALPHA(5) -GABA(A) RECEPTOR AND ENABLED L-655,708 ANTINOCICEPTIVE EFFECT IN MALE RATS. THESE RESULTS SUGGEST THAT ALPHA(5) -GABA(A) RECEPTOR IS A SUITABLE TARGET TO TREAT CHRONIC PAIN IN FEMALES. 2021 7 4397 45 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 8 4213 33 METHIONINE MEDIATES RESILIENCE TO CHRONIC SOCIAL DEFEAT STRESS BY EPIGENETIC REGULATION OF NMDA RECEPTOR SUBUNIT EXPRESSION. RATIONALE: PREVIOUS STUDIES SUGGESTED THAT METHIONINE (MET) LEVELS ARE DECREASED IN DEPRESSED PATIENTS. HOWEVER, WHETHER THE DECREASE IN THIS AMINO ACID IS IMPORTANT FOR PHENOTYPIC BEHAVIORS ASSOCIATED WITH DEPRESSION HAS NOT BEEN DECIPHERED. OBJECTIVE: THE RESPONSE OF INDIVIDUALS TO CHRONIC STRESS IS VARIABLE, WITH SOME INDIVIDUALS DEVELOPING DEPRESSION AND OTHERS BECOMING RESILIENT TO STRESS. IN THIS STUDY, OUR OBJECTIVE WAS TO EXAMINE THE EFFECT OF MET ON SUSCEPTIBILITY TO STRESS. METHODS: MALE C57BL/6J MICE WERE SUBJECTED TO DAILY DEFEAT SESSIONS BY A CD1 AGGRESSOR, FOR 10 DAYS. ON DAY 11, THE BEHAVIOR OF MICE WAS ASSESSED USING SOCIAL INTERACTION AND OPEN-FIELD TESTS. MICE RECEIVED MET 4 H BEFORE EACH DEFEAT SESSION. EPIGENETIC TARGETS WERE ASSESSED EITHER THROUGH REAL-RIME RTPCR OR THROUGH WESTERN BLOTS. RESULTS: MET DID NOT MODULATE ANXIETY-LIKE BEHAVIORS, BUT RATHER PROMOTED RESILIENCE TO CHRONIC STRESS, RESCUED SOCIAL AVOIDANCE BEHAVIORS AND REVERSED THE INCREASE IN THE CORTICAL EXPRESSION LEVELS OF N-METHYL-D-ASPARTATE RECEPTOR (NMDAR) SUBUNITS. ACTIVATING NMDAR ACTIVITY ABOLISHED THE ABILITY OF MET TO PROMOTE RESILIENCE TO STRESS AND TO RESCUE SOCIAL AVOIDANCE BEHAVIOR, WHEREAS INHIBITING NMDAR DID NOT SHOW ANY SYNERGISTIC OR ADDITIVE PROTECTIVE EFFECTS. INDEED, MET INCREASED THE CORTICAL LEVELS OF THE HISTONE METHYLTRANSFERASE SETDB1, AND IN TURN, THE LEVELS OF THE REPRESSIVE HISTONE H3 LYSINE (K9) TRIMETHYLATION (ME3). CONCLUSIONS: OUR DATA INDICATE THAT MET RESCUES SUSCEPTIBILITY TO STRESS BY INACTIVATING CORTICAL NMDAR ACTIVITY THROUGH AN EPIGENETIC MECHANISM INVOLVING HISTONE METHYLATION. 2020 9 2745 32 EXPRESS: HISTONE HYPERACETYLATION MODULATES SPINAL TYPE II METABOTROPIC GLUTAMATE RECEPTOR ALLEVIATING STRESS-INDUCED VISCERAL HYPERSENSITIVITY IN FEMALE RATS. STRESS IS OFTEN A TRIGGER TO EXACERBATE CHRONIC PAIN INCLUDING VISCERAL HYPERSENSITIVITY ASSOCIATED WITH IRRITABLE BOWEL SYNDROME, A FEMALE PREDOMINANT FUNCTIONAL BOWEL DISORDER. EPIGENETIC MECHANISMS THAT MEDIATE STRESS RESPONSES ARE A POTENTIAL TARGET TO INTERFERE WITH VISCERAL PAIN. THE PURPOSE OF THIS STUDY WAS TO EXAMINE THE EFFECT OF A HISTONE DEACETYLASE INHIBITOR, SUBEROYLANILIDE HYDROXAMIC ACID, ON VISCERAL HYPERSENSITIVITY INDUCED BY A SUBCHRONIC STRESSOR IN FEMALE RATS AND TO INVESTIGATE THE INVOLVEMENT OF SPINAL GLUTAMATE RECEPTORS. THREE DAILY SESSIONS OF FORCED SWIM INDUCED VISCERAL HYPERSENSITIVITY. INTRATHECAL SUBEROYLANILIDE HYDROXAMIC ACID PREVENTED OR REVERSED THE STRESS-INDUCED VISCERAL HYPERSENSITIVITY, INCREASED SPINAL HISTONE 3 ACETYLATION AND INCREASED MGLUR2 AND MGLUR3 EXPRESSION. CHROMATIN IMMUNOPRECIPITATION (CHIP) ANALYSIS REVEALED ENRICHMENT OF H3K9AC AND H3K18AC AT SEVERAL PROMOTER GRM2 AND GRM3 REGIONS. THE MGLUR2/3 ANTAGONIST LY341495 REVERSED THE INHIBITORY EFFECT OF SUBEROYLANILIDE HYDROXAMIC ACID ON THE STRESS-INDUCED VISCERAL HYPERSENSITIVITY. IN SURPRISING CONTRAST, STRESS AND/OR SUBEROYLANILIDE HYDROXAMIC ACID HAD NO EFFECT ON SPINAL NMDA RECEPTOR EXPRESSION OR FUNCTION. THESE DATA REVEAL HISTONE MODIFICATION MODULATES MGLUR2/3 EXPRESSION IN THE SPINAL CORD TO ATTENUATE STRESSINDUCED VISCERAL HYPERSENSITIVITY. HDAC INHIBITORS MAY PROVIDE A POTENTIAL APPROACH TO RELIEVE VISCERAL HYPERSENSITIVITY ASSOCIATED WITH IRRITABLE BOWEL SYNDROME. 2016 10 5021 35 PERSISTENT PAIN MAINTAINS MORPHINE-SEEKING BEHAVIOR AFTER MORPHINE WITHDRAWAL THROUGH REDUCED MECP2 REPRESSION OF GLUA1 IN RAT CENTRAL AMYGDALA. AS LONG-TERM OPIOIDS ARE INCREASINGLY USED FOR CONTROL OF CHRONIC PAIN, HOW PAIN AFFECTS THE REWARDING EFFECT OF OPIOIDS AND HENCE RISK OF PRESCRIPTION OPIOID MISUSE AND ABUSE REMAINS A HEALTHCARE CONCERN AND A CHALLENGING ISSUE IN CURRENT PAIN MANAGEMENT. IN THIS STUDY, USING A RAT MODEL OF MORPHINE SELF-ADMINISTRATION, WE INVESTIGATED THE MOLECULAR MECHANISMS UNDERLYING THE IMPACT OF PAIN ON OPERANT BEHAVIOR OF MORPHINE INTAKE AND MORPHINE SEEKING BEFORE AND AFTER MORPHINE WITHDRAWAL. WE FOUND THAT RATS WITH PERSISTENT PAIN CONSUMED A SIMILAR AMOUNT OF DAILY MORPHINE TO THAT IN CONTROL RATS WITHOUT PAIN, BUT MAINTAINED THEIR LEVEL-PRESSING BEHAVIOR OF MORPHINE SEEKING AFTER ABSTINENCE OF MORPHINE AT 0.2 MG/KG, WHEREAS THIS BEHAVIOR WAS GRADUALLY DIMINISHED IN CONTROL RATS. IN THE CENTRAL NUCLEUS OF AMYGDALA (CEA), A LIMBIC STRUCTURE CRITICALLY INVOLVED IN THE AFFECTIVE DIMENSION OF PAIN, PROTEINS OF GLUA1 SUBUNITS OF GLUTAMATE AMPA RECEPTORS WERE UPREGULATED DURING MORPHINE WITHDRAWAL, AND VIRAL KNOCKDOWN OF CEA GLUA1 ELIMINATED THE MORPHINE-SEEKING BEHAVIOR IN WITHDRAWN RATS OF THE PAIN GROUP. CHROMATIN IMMUNOPRECIPITATION ANALYSIS REVEALED THAT THE METHYL CPG-BINDING PROTEIN 2 (MECP2) WAS ENRICHED IN THE PROMOTER REGION OF GRIA1 ENCODING GLUA1 AND THIS ENRICHMENT WAS SIGNIFICANTLY ATTENUATED IN WITHDRAWN RATS OF THE PAIN GROUP. FURTHERMORE, VIRAL OVEREXPRESSION OF CEA MECP2 REPRESSED THE GLUA1 LEVEL AND ELIMINATED THE MAINTENANCE OF MORPHINE-SEEKING BEHAVIOR AFTER MORPHINE WITHDRAWAL. THESE RESULTS SUGGEST DIRECT MECP2 REPRESSION OF GLUA1 FUNCTION AS A LIKELY MECHANISM FOR MORPHINE-SEEKING BEHAVIOR MAINTAINED BY LONG-LASTING AFFECTIVE PAIN AFTER MORPHINE WITHDRAWAL. 2015 11 742 34 CANNABINOID CB2 RECEPTORS ARE UPREGULATED VIA BIVALENT HISTONE MODIFICATIONS AND CONTROL PRIMARY AFFERENT INPUT TO THE SPINAL CORD IN NEUROPATHIC PAIN. TYPE-2 CANNABINOID RECEPTORS (CB2, ENCODED BY THE CNR2 GENE) ARE MAINLY EXPRESSED IN IMMUNE CELLS, AND CB2 AGONISTS NORMALLY HAVE NO ANALGESIC EFFECT. HOWEVER, NERVE INJURY UPREGULATES CB2 IN THE DORSAL ROOT GANGLION (DRG), FOLLOWING WHICH CB2 STIMULATION REDUCES NEUROPATHIC PAIN. IT IS UNCLEAR HOW NERVE INJURY INCREASES CB2 EXPRESSION OR HOW CB2 ACTIVITY IS TRANSFORMED IN NEUROPATHIC PAIN. IN THIS STUDY, IMMUNOBLOTTING SHOWED THAT SPINAL NERVE LIGATION (SNL) INDUCED A DELAYED AND SUSTAINED INCREASE IN CB2 EXPRESSION IN THE DRG AND DORSAL SPINAL CORD SYNAPTOSOMES. RNASCOPE IN SITU HYBRIDIZATION ALSO SHOWED THAT SNL SUBSTANTIALLY INCREASED CB2 MRNA LEVELS, MOSTLY IN MEDIUM AND LARGE DRG NEURONS. FURTHERMORE, WE FOUND THAT THE SPECIFIC CB2 AGONIST JWH-133 SIGNIFICANTLY INHIBITS THE AMPLITUDE OF DORSAL ROOT-EVOKED GLUTAMATERGIC EXCITATORY POSTSYNAPTIC CURRENTS IN SPINAL DORSAL HORN NEURONS IN SNL RATS, BUT NOT IN SHAM CONTROL RATS; INTRATHECAL INJECTION OF JWH-133 REVERSED PAIN HYPERSENSITIVITY IN SNL RATS, BUT HAD NO EFFECT IN SHAM CONTROL RATS. IN ADDITION, CHROMATIN IMMUNOPRECIPITATION-QPCR ANALYSIS SHOWED THAT SNL INCREASED ENRICHMENT OF TWO ACTIVATING HISTONE MARKS (H3K4ME3 AND H3K9AC) AND DIMINISHED OCCUPANCY OF TWO REPRESSIVE HISTONE MARKS (H3K9ME2 AND H3K27ME3) AT THE CNR2 PROMOTER IN THE DRG. IN CONTRAST, SNL HAD NO EFFECT ON DNA METHYLATION LEVELS AROUND THE CNR2 PROMOTER. OUR FINDINGS SUGGEST THAT PERIPHERAL NERVE INJURY PROMOTES CB2 EXPRESSION IN PRIMARY SENSORY NEURONS VIA EPIGENETIC BIVALENT HISTONE MODIFICATIONS AND THAT CB2 ACTIVATION REDUCES NEUROPATHIC PAIN BY ATTENUATING NOCICEPTIVE TRANSMISSION FROM PRIMARY AFFERENT NERVES TO THE SPINAL CORD. 2022 12 4615 35 NERVE INJURY DIMINISHES OPIOID ANALGESIA THROUGH LYSINE METHYLTRANSFERASE-MEDIATED TRANSCRIPTIONAL REPRESSION OF MU-OPIOID RECEPTORS IN PRIMARY SENSORY NEURONS. THE MU-OPIOID RECEPTOR (MOR, ENCODED BY OPRM1) AGONISTS ARE THE MAINSTAY ANALGESICS FOR TREATING MODERATE TO SEVERE PAIN. NERVE INJURY CAUSES DOWN-REGULATION OF MORS IN THE DORSAL ROOT GANGLION (DRG) AND DIMINISHES THE OPIOID EFFECT ON NEUROPATHIC PAIN. HOWEVER, THE EPIGENETIC MECHANISMS UNDERLYING THE DIMINISHED MOR EXPRESSION CAUSED BY NERVE INJURY ARE NOT CLEAR. G9A (ENCODED BY EHMT2), A HISTONE 3 AT LYSINE 9 METHYLTRANSFERASE, IS A KEY CHROMATIN REGULATOR RESPONSIBLE FOR GENE SILENCING. IN THIS STUDY, WE DETERMINED THE ROLE OF G9A IN DIMINISHED MOR EXPRESSION AND OPIOID ANALGESIC EFFECTS IN ANIMAL MODELS OF NEUROPATHIC PAIN. WE FOUND THAT NERVE INJURY IN RATS INDUCED A LONG-LASTING REDUCTION IN THE EXPRESSION LEVEL OF MORS IN THE DRG BUT NOT IN THE SPINAL CORD. NERVE INJURY CONSISTENTLY INCREASED THE ENRICHMENT OF THE G9A PRODUCT HISTONE 3 AT LYSINE 9 DIMETHYLATION IN THE PROMOTER OF OPRM1 IN THE DRG. G9A INHIBITION OR SIRNA KNOCKDOWN FULLY REVERSED MOR EXPRESSION IN THE INJURED DRG AND POTENTIATED THE MORPHINE EFFECT ON PAIN HYPERSENSITIVITY INDUCED BY NERVE INJURY. IN MICE LACKING EHMT2 IN DRG NEURONS, NERVE INJURY FAILED TO REDUCE THE EXPRESSION LEVEL OF MORS AND THE MORPHINE EFFECT. IN ADDITION, G9A INHIBITION OR EHMT2 KNOCKOUT IN DRG NEURONS NORMALIZED NERVE INJURY-INDUCED REDUCTION IN THE INHIBITORY EFFECT OF THE OPIOID ON SYNAPTIC GLUTAMATE RELEASE FROM PRIMARY AFFERENT NERVES. OUR FINDINGS INDICATE THAT G9A CONTRIBUTES CRITICALLY TO TRANSCRIPTIONAL REPRESSION OF MORS IN PRIMARY SENSORY NEURONS IN NEUROPATHIC PAIN. G9A INHIBITORS MAY BE USED TO ENHANCE THE OPIOID ANALGESIC EFFECT IN THE TREATMENT OF CHRONIC NEUROPATHIC PAIN. 2016 13 893 37 CHRONIC ETHANOL EXPOSURE AND WITHDRAWAL IMPAIR SYNAPTIC GABA(A) RECEPTOR-MEDIATED NEUROTRANSMISSION IN DEEP-LAYER PREFRONTAL CORTEX. BACKGROUND: THE PREFRONTAL CORTEX (PFC) ACTS AS AN INTEGRATIVE HUB FOR THE PROCESSING OF CORTICAL AND SUBCORTICAL INPUT INTO MEANINGFUL EFFERENT SIGNALING, PERMITTING COMPLEX ASSOCIATIVE BEHAVIORS. PFC DYSFUNCTION IS CONSISTENTLY OBSERVED WITH ETHANOL (ETOH) DEPENDENCE AND IS A CORE COMPONENT OF THE PATHOLOGY OF ALCOHOL USE DISORDERS IN CURRENT MODELS OF ADDICTION. WHILE INTRACORTICAL GAMMA-AMINOBUTRYRIC ACID (GABA)ERGIC NEUROTRANSMISSION IS UNDERSTOOD TO BE ESSENTIAL FOR MAINTAINING COORDINATED NETWORK ACTIVITY WITHIN THE CORTEX, RELATIVELY LITTLE IS KNOWN REGARDING FUNCTIONAL GABAERGIC ADAPTATIONS IN PFC DURING ETOH DEPENDENCE. METHODS: IN THE PRESENT STUDY, MALE AND FEMALE (> POSTNATAL DAY 60) SPRAGUE-DAWLEY RATS WERE ADMINISTERED ETOH (5.0 G/KG; INTRAGASTRIC GAVAGE) FOR 14 TO 15 CONSECUTIVE DAYS. TWENTY-FOUR HOURS AFTER THE FINAL ADMINISTRATION, ANIMALS WERE SACRIFICED AND BRAINS EXTRACTED FOR ELECTROPHYSIOLOGICAL RECORDINGS OF ISOLATED GABA(A) RECEPTOR-MEDIATED CURRENTS OR ANALYSIS OF GABA(A) RECEPTOR SUBUNIT PROTEIN EXPRESSION IN DEEP-LAYER PFC NEURONS. RESULTS: CHRONIC ETOH EXPOSURE SIGNIFICANTLY ATTENUATED ACTIVITY-DEPENDENT SPONTANEOUS GABA(A) RECEPTOR-MEDIATED INHIBITORY POSTSYNAPTIC CURRENT (IPSC) FREQUENCY WITH NO EFFECT ON AMPLITUDE. FURTHERMORE, ANALYSIS OF IPSC DECAY KINETICS REVEALED A SIGNIFICANT ENHANCEMENT OF IPSC DECAY TIME THAT WAS ASSOCIATED WITH DECREMENTS IN EXPRESSION OF THE ALPHA1 GABA(A) RECEPTOR SUBUNIT, INDICATIVE OF FURTHER IMPAIRED PHASIC INHIBITION. THESE PHENOMENA OCCURRED IRRESPECTIVE OF NEURON PROJECTION DESTINATION AND SEX. BASED ON PREVIOUS OBSERVATIONS BY OUR LABORATORY OF AN EPIGENETIC MECHANISM FOR ETOH-INDUCED CHANGES IN CORTICAL GABA(A) RECEPTOR SUBUNIT EXPRESSION, THE HISTONE DEACETYLASE INHIBITOR TRICHOSTATIN A WAS ADMINISTERED TO WATER- AND ETOH-EXPOSED ANIMALS, AND PREVENTED ETOH-INDUCED CHANGES IN SPONTANEOUS IPSC FREQUENCY, IPSC DECAY KINETICS, AND GABA(A) RECEPTOR SUBUNIT EXPRESSION. CONCLUSIONS: TAKEN TOGETHER, THESE RESULTS DEMONSTRATE THAT CHRONIC ETOH EXPOSURE IMPAIRS SYNAPTIC INHIBITORY NEUROTRANSMISSION IN DEEP-LAYER PYRAMIDAL NEURONS OF THE MEDIAL PFC IN BOTH MALE AND FEMALE RATS. THESE MALADAPTATIONS OCCUR IN NEURONS PROJECTING TO NUMEROUS REGIONS IMPLICATED IN THE SEQUELAE OF ETOH DEPENDENCE, OFFERING A MECHANISTIC LINK BETWEEN THE MANIFESTATION OF PFC DYSFUNCTION AND NEGATIVE AFFECTIVE STATES OBSERVED WITH EXTENDED CONSUMPTION. 2019 14 6108 39 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 69 34 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 16 5006 52 PERIPHERAL NERVE INJURY IS ACCOMPANIED BY CHRONIC TRANSCRIPTOME-WIDE CHANGES IN THE MOUSE PREFRONTAL CORTEX. BACKGROUND: PERIPHERAL NERVE INJURY CAN HAVE LONG-TERM CONSEQUENCES INCLUDING PAIN-RELATED MANIFESTATIONS, SUCH AS HYPERSENSITIVITY TO CUTANEOUS STIMULI, AS WELL AS AFFECTIVE AND COGNITIVE DISTURBANCES, SUGGESTING THE INVOLVEMENT OF SUPRASPINAL MECHANISMS. CHANGES IN BRAIN STRUCTURE AND CORTICAL FUNCTION ASSOCIATED WITH MANY CHRONIC PAIN CONDITIONS HAVE BEEN REPORTED IN THE PREFRONTAL CORTEX (PFC). THE PFC IS IMPLICATED IN PAIN-RELATED CO-MORBIDITIES SUCH AS DEPRESSION, ANXIETY AND IMPAIRED EMOTIONAL DECISION-MAKING ABILITY. WE RECENTLY REPORTED THAT THIS REGION IS SUBJECT TO SIGNIFICANT EPIGENETIC REPROGRAMMING FOLLOWING PERIPHERAL NERVE INJURY, AND NORMALIZATION OF PAIN-RELATED STRUCTURAL, FUNCTIONAL AND EPIGENETIC ABNORMALITIES IN THE PFC ARE ALL ASSOCIATED WITH EFFECTIVE PAIN REDUCTION. IN THIS STUDY, WE USED THE SPARED NERVE INJURY (SNI) MODEL OF NEUROPATHIC PAIN TO TEST THE HYPOTHESIS THAT PERIPHERAL NERVE INJURY TRIGGERS PERSISTENT LONG-LASTING CHANGES IN GENE EXPRESSION IN THE PFC, WHICH ALTER FUNCTIONAL GENE NETWORKS, THUS PROVIDING A POSSIBLE EXPLANATION FOR CHRONIC PAIN ASSOCIATED BEHAVIORS. RESULTS: SNI OR SHAM SURGERY WHERE PERFORMED IN MALE CD1 MICE AT THREE MONTHS OF AGE. SIX MONTHS AFTER INJURY, WE PERFORMED TRANSCRIPTOME-WIDE SEQUENCING (RNASEQ), WHICH REVEALED 1147 DIFFERENTIALLY REGULATED TRANSCRIPTS IN THE PFC IN NERVE-INJURED VS. CONTROL MICE. CHANGES IN GENE EXPRESSION OCCURRED ACROSS A NUMBER OF FUNCTIONAL GENE CLUSTERS ENCODING CARDINAL BIOLOGICAL PROCESSES AS REVEALED BY INGENUITY PATHWAY ANALYSIS. SIGNIFICANTLY ALTERED BIOLOGICAL PROCESSES INCLUDED NEUROLOGICAL DISEASE, SKELETAL MUSCULAR DISORDERS, BEHAVIOR, AND PSYCHOLOGICAL DISORDERS. SEVERAL OF THE CHANGES DETECTED BY RNASEQ WERE VALIDATED BY RT-QPCR AND INCLUDED TRANSCRIPTS WITH KNOWN ROLES IN CHRONIC PAIN AND/OR NEURONAL PLASTICITY INCLUDING THE NMDA RECEPTOR (GLUTAMATE RECEPTOR, IONOTROPIC, NMDA; GRIN1), NEURITE OUTGROWTH (ROUNDABOUT 3; ROBO3), GLIOSIS (GLIAL FIBRILLARY ACIDIC PROTEIN; GFAP), VESICULAR RELEASE (SYNAPTOTAGMIN 2; SYT2), AND NEURONAL EXCITABILITY (VOLTAGE-GATED SODIUM CHANNEL, TYPE I; SCN1A). CONCLUSIONS: THIS STUDY USED AN UNBIASED APPROACH TO DOCUMENT LONG-TERM ALTERATIONS IN GENE EXPRESSION IN THE BRAIN FOLLOWING PERIPHERAL NERVE INJURY. WE PROPOSE THAT THESE CHANGES ARE MAINTAINED AS A MEMORY OF AN INSULT THAT IS TEMPORALLY AND SPATIALLY DISTANT FROM THE INITIAL INJURY. 2013 17 1320 40 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 18 4581 24 N-METHYL-D-ASPARTATE 2B RECEPTOR SUBTYPE (NR2B) PROMOTER METHYLATION IN PATIENTS DURING ALCOHOL WITHDRAWAL. NMDA RECEPTORS AND ESPECIALLY THE NR2B RECEPTOR SUBTYPE PLAY A CRUCIAL ROLE DURING CHRONIC ETHANOL CONSUMPTION AND ALCOHOL WITHDRAWAL. THEREFORE, THE NR2B RECEPTOR SUBTYPE EXPRESSION IN PERIPHERAL BLOOD CELLS OF 32 MALE PATIENTS SUFFERING FROM ALCOHOL DEPENDENCY WERE ASSESSED THROUGH QUANTITATIVE RT-PCR AND TO EXPLORE REGULATING EPIGENETIC MECHANISMS, A METHYLATION ANALYSIS WAS CONDUCTED USING BISULFITE SEQUENCING OF A FRAGMENT OF THE NR2B PROMOTER REGION. THE EXPRESSION OF THE NR2B RECEPTOR INCREASED SIGNIFICANTLY DURING THE FIRST 24 H OF WITHDRAWAL TREATMENT (DAY 1; T = 4.1, P = 0.001), AND ALSO ON AND DAY 3 (T = 2.4; P = 0.029). THE SEVERITY OF ALCOHOL DRINKING PATTERN, MEASURED BY LIFETIME DRINKING AND DAILY ETHANOL INTAKE, WAS NEGATIVELY CORRELATED WITH THE METHYLATION OF A DEFINED CLUSTER OF FIVE CPG-SITES WITHIN THE NR2B PROMOTER (LIFETIME DRINKING: SPEARMAN'S RHO = -0.55; P = 0.013; DAILY ETHANOL INTAKE: RHO = -0.46; P = 0.043). THESE FINDINGS MIGHT EXPLAIN THE OBSERVATION OF AN IMPACT OF ALCOHOL CONSUMPTION PATTERNS ON THE GRAVITY OF WITHDRAWAL SYMPTOMS. 2009 19 2300 33 EPIGENETIC REGULATION OF BDNF EXPRESSION IN THE PRIMARY SENSORY NEURONS AFTER PERIPHERAL NERVE INJURY: IMPLICATIONS IN THE DEVELOPMENT OF NEUROPATHIC PAIN. BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) IS KNOWN TO BE UP-REGULATED IN THE DORSAL ROOT GANGLION (DRG) AFTER PERIPHERAL NERVE INJURY, AND TO CONTRIBUTE TO NEUROPATHIC PAIN. HERE, WE FOUND THAT THERMAL HYPERALGESIA AND MECHANICAL ALLODYNIA AT DAY 7 POST-INJURY WERE INHIBITED ONLY WHEN ANTI-BDNF ANTIBODY WAS INTRATHECALLY ADMINISTRATED AT DAY 2 POST-INJURY. CONSISTENT WITH BEHAVIORAL RESULTS, WESTERN BLOT ANALYSIS SHOWED THAT THE EXPRESSION LEVELS OF BDNF PROTEIN IN THE SPINAL DORSAL HORN WERE MARKEDLY INDUCED DURING EARLY STAGE POST-INJURY. MOREOVER, THE MAXIMAL INCREASE IN BDNF MRNA EXPRESSION IN THE DRG WAS OBSERVED AT DAY 1 POST-INJURY, AND SIGNIFICANTLY ELEVATED LEVELS WERE SUSTAINED FOR AT LEAST 14 DAYS. FOUR OF FIVE BDNF MRNA TRANSCRIPTS WERE UP-REGULATED AFTER NERVE INJURY, AND THE MOST INDUCIBLE TRANSCRIPT WAS EXON I. USING A CHROMATIN IMMUNOPRECIPITATION (CHIP) ASSAY, WE FOUND THAT NERVE INJURY PROMOTES HISTONE H3 AND H4 ACETYLATION, TRANSCRIPTIONALLY ACTIVE MODIFICATIONS, AT BDNF PROMOTER I AT DAY 1 POST-INJURY, AND THE LEVELS OF HISTONE ACETYLATION REMAIN ELEVATED FOR AT LEAST 7 DAYS. TAKEN TOGETHER, OUR FINDINGS SUGGEST THAT AN INITIAL INCREASE IN BDNF EXON I EXPRESSION CONTROLLED BY EPIGENETIC MECHANISMS MIGHT HAVE A CRUCIAL ROLE IN THE DEVELOPMENT OF NEUROPATHIC PAIN. 2013 20 687 39 BRAINSTEM BRAIN-DERIVED NEUROTROPHIC FACTOR SIGNALING IS REQUIRED FOR HISTONE DEACETYLASE INHIBITOR-INDUCED PAIN RELIEF. OUR PREVIOUS STUDY DEMONSTRATED THAT PERSISTENT PAIN CAN EPIGENETICALLY SUPPRESS THE TRANSCRIPTION OF GAD2 [ENCODING GLUTAMIC ACID DECARBOXYLASE 65 (GAD65)] AND CONSEQUENTLY IMPAIR THE INHIBITORY FUNCTION OF GABAERGIC SYNAPSES IN CENTRAL PAIN-MODULATING NEURONS. THIS CONTRIBUTES TO THE DEVELOPMENT OF PERSISTENT PAIN SENSITIZATION. HISTONE DEACETYLASE (HDAC) INHIBITORS INCREASED GAD65 ACTIVITY CONSIDERABLY, RESTORED GABA SYNAPTIC FUNCTION, AND RENDERED SENSITIZED PAIN BEHAVIOR LESS PRONOUNCED. HOWEVER, THE MOLECULAR MECHANISMS BY WHICH HDAC REGULATES GABAERGIC TRANSMISSION THROUGH GAD65 UNDER PAIN CONDITIONS ARE UNKNOWN. THIS WORK SHOWED THAT HDAC INHIBITOR-INDUCED INCREASES IN COLOCALIZATION OF GAD65 AND SYNAPTIC PROTEIN SYNAPSIN I ON THE PRESYNAPTIC AXON TERMINALS OF THE NUCLEUS RAPHE MAGNUS (NRM) WERE BLOCKED BY A TRKB RECEPTOR ANTAGONIST K252A [(9S,10R,12R)-2,3,9,10,11,12-HEXAHYDRO-10-HYDROXY-9-METHYL-1-OXO-9,12-EPOXY-1H-DIINDOLO[1,2,3-FG:3',2',1'-KL]PYRROLO[3,4-I][1,6]BENZODIAZOCINE-10-CARBOXYLIC ACID METHYL ESTER], INDICATING THAT BDNF-TRKB SIGNALING MAY BE REQUIRED IN GAD65 MODULATION OF GABA SYNAPTIC FUNCTION. AT THE BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) PROMOTER, HDAC INHIBITORS INDUCED SIGNIFICANT INCREASES IN H3 HYPERACETYLATION, CONSISTENT WITH THE INCREASE IN BDNF MRNA AND TOTAL PROTEINS. ALTHOUGH EXOGENOUS BDNF FACILITATED GABA MINIATURE INHIBITORY POSTSYNAPTIC CURRENTS AND GAD65 ACCUMULATION IN NRM NEURONAL SYNAPSES IN NORMAL RATS, IT FAILED TO DO SO IN ANIMALS SUBJECTED TO PERSISTENT INFLAMMATION. IN ADDITION, BLOCKADE OF THE TRKB RECEPTOR WITH K252A HAS NO EFFECT ON MINIATURE INHIBITORY POSTSYNAPTIC CURRENTS AND SYNAPTIC GAD65 ACCUMULATION UNDER NORMAL CONDITIONS. IN ADDITION, THE ANALGESIC EFFECTS OF HDAC INHIBITORS ON BEHAVIOR WERE BLOCKED BY NRM INFUSION OF K252A. THESE FINDINGS SUGGEST THAT BDNF-TRKB SIGNALING IS REQUIRED FOR DRUGS THAT REVERSE THE EPIGENETIC EFFECTS OF CHRONIC PAIN AT THE GENE LEVEL, SUCH AS HDAC INHIBITORS. 2015