1 5297 164 PROTEIN ARGININE METHYLTRANSFERASE 5 CONTRIBUTES TO PACLITAXEL-INDUCED NEUROPATHIC PAIN BY ACTIVATING TRANSIENT RECEPTOR POTENTIAL VANILLOID 1 EPIGENETIC MODIFICATION IN DORSAL ROOT GANGLION. BACKGROUND: PACLITAXEL (PTX), WHICH IS A FIRST-LINE CHEMOTHERAPY DRUG USED TO TREAT VARIOUS TYPES OF CANCERS, EXHIBITS PERIPHERAL NEUROPATHY AS A COMMON SIDE EFFECT THAT IS DIFFICULT TO TREAT. PROTEIN ARGININE METHYLTRANSFERASE 5 (PRMT 5) IS A KEY REGULATOR OF THE CHEMOTHERAPY RESPONSE, AS CHEMOTHERAPY DRUGS INDUCE PRMT5 EXPRESSION. HOWEVER, LITTLE IS KNOWN ABOUT THE PRMT5-MEDIATED EPIGENETIC MECHANISMS INVOLVED IN PTX-INDUCED NEUROPATHIC ALLODYNIA. METHODS: SPRAGUE-DAWLEY RATS WERE INTRAPERITONEALLY GIVEN PTX TO INDUCE NEUROPATHIC PAIN. BIOCHEMICAL ANALYSES WERE CONDUCTED TO MEASURE THE PROTEIN EXPRESSION LEVELS IN THE DORSAL ROOT GANGLION (DRG) OF THE ANIMALS. THE VON FREY TEST AND HOT PLATE TEST WERE USED TO EVALUATE NOCICEPTIVE BEHAVIORS. RESULTS: PTX INCREASED THE PRMT5 (MEAN DIFFERENCE [MD]: 0.68, 95% CONFIDENCE INTERVAL [CI], 0.88-0.48; P < .001 FOR VEHICLE)-MEDIATED DEPOSITION OF HISTONE H3R2 DIMETHYL SYMMETRIC (H3R2ME2S) AT THE TRANSIENT RECEPTOR POTENTIAL VANILLOID 1 (TRPV1) PROMOTER IN THE DRG. PRMT5-INDUCED H3R2ME2S RECRUITED WD REPEAT DOMAIN 5 (WDR5) TO INCREASE TRIMETHYLATION OF LYSINE 4 ON HISTONE H3 (H3K4ME3) AT TRPV1 PROMOTERS, THUS RESULTING IN TRPV1 TRANSCRIPTIONAL ACTIVATION (MD: 0.65, 95% CI, 0.82-0.49; P < .001 FOR VEHICLE) IN DRG IN PTX-INDUCED NEUROPATHIC PAIN. MOREOVER, PTX INCREASED THE ACTIVITY OF NADPH OXIDASE 4 (NOX4) (MD: 0.66, 95% CI, 0.81-0.51; P < .001 FOR VEHICLE), PRMT5-INDUCED H3R2ME2S, AND WDR5-MEDIATED H3K4ME3 IN THE DRG IN PTX-INDUCED NEUROPATHIC PAIN. PHARMACOLOGICAL ANTAGONISM AND THE SELECTIVE KNOCKDOWN OF PRMT5 IN DRG NEURONS COMPLETELY BLOCKED PRMT5-MEDIATED H3R2ME2S, WDR5-MEDIATED H3K4ME3, OR TRPV1 EXPRESSION AND NEUROPATHIC PAIN DEVELOPMENT AFTER PTX INJECTION. REMARKABLY, NOX4 INHIBITION NOT ONLY ATTENUATED ALLODYNIA BEHAVIOR AND REVERSED THE ABOVE-MENTIONED SIGNALING BUT ALSO REVERSED NOX4 UPREGULATION VIA PTX. CONCLUSIONS: THUS, THE NOX4/PRMT5-ASSOCIATED EPIGENETIC MECHANISM IN DRG HAS A DOMINANT FUNCTION IN THE TRANSCRIPTIONAL ACTIVATION OF TRPV1 IN PTX-INDUCED NEUROPATHIC PAIN. 2023 2 4993 30 PENTOXIFYLLINE-INDUCED PROTEIN EXPRESSION CHANGE IN RAW 264.7 CELLS AS DETERMINED BY IMMUNOPRECIPITATION-BASED HIGH PERFORMANCE LIQUID CHROMATOGRAPHY. ALTHOUGH PENTOXIFYLLINE (PTX) WAS IDENTIFIED AS A COMPETITIVE NON-SELECTIVE PHOSPHODIESTERASE INHIBITOR, ITS PHARMACOLOGICAL EFFECT HAS NOT BEEN CLEARLY ELUCIDATED. THE PRESENT STUDY EXPLORED THE EFFECT OF LOW DOSE 10 MUG/ML PTX (THERAPEUTIC DOSE) COMPARED TO HIGH DOSE 300 MUG/ML PTX (EXPERIMENTAL DOSE) IN RAW 264.7 CELLS THROUGH IMMUNOPRECIPITATION-BASED HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (IP-HPLC), IMMUNOHISTOCHEMISTRY, AND WESTERN BLOT. 10 MUG/ML PTX INCREASED THE EXPRESSION OF PROLIFERATION (KI-67, PCNA, CYCLIN D2, CDC25A), EPIGENETIC MODIFICATION (KDM4D, PCAF, HMGB1), PROTEIN TRANSLATION (DOHH, DHPS, EIF5A1), RAS SIGNALING (KRAS, PAKT1/2/3, PI3K), NFKB SIGNALING (NFKB, GADD45, P38), PROTECTION (HSP70, SOD1, GSTO1/2), SURVIVAL (PAKT1/2/3, SP1, SIRTUIN 6), NEUROMUSCULAR DIFFERENTIATION (NSEGAMMA, MYOSIN-1A, DESMIN), OSTEOBLASTIC DIFFERENTIATION (BMP2, RUNX2, OSTERIX), ACUTE INFLAMMATION (TNFALPHA, IL-1, CXCR4), INNATE IMMUNITY (BETA-DEFENSIN 1, LACTOFERRIN, TLR-3, -4), CELL-MEDIATED IMMUNITY (CD4, CD8, CD80), WHILE DECREASED THE EXPRESSION OF ER STRESS (EIF2ALPHA, EIF2AK3, ATF6ALPHA), FIBROSIS (FGF2, CTGF, COLLAGEN 3A1), AND CHRONIC INFLAMMATION (CD68, MMP-2, -3, COX2) VERSUS THE UNTREATED CONTROLS. THE ACTIVATION OF PROLIFERATION BY 10 MUG/ML PTX WAS ALSO SUPPORTED BY THE INCREASE OF CMYC-MAX HETERODIMER AND BETA-CATENIN-TCF1 COMPLEX IN DOUBLE IP-HPLC. 10 MUG/ML PTX ENHANCED FAS-MEDIATED APOPTOSIS BUT DIMINISHED P53-MEDIATED APOPTOSIS, AND DOWNREGULATED MANY ANGIOGENESIS PROTEINS (ANGIOGENIN, VEGF-A, AND FLT4), BUT UPREGULATED HIF1ALPHA, VEGFR2, AND CMG2 REACTIVELY. WHEREAS, 300 MUG/ML PTX CONSISTENTLY DECREASED PROLIFERATION, EPIGENETIC MODIFICATION, RAS AND NFKB SIGNALING, NEUROMUSCULAR AND OSTEOBLASTIC DIFFERENTIATION, BUT INCREASED APOPTOSIS, ER STRESS, AND FIBROSIS COMPARED TO 10 MUG/ML PTX. THESE DATA SUGGEST PTX HAS DIFFERENT BIOLOGICAL EFFECT ON RWA 264.7 CELLS DEPENDING ON THE CONCENTRATION OF 10 MUG/ML AND 300 MUG/ML PTX. THE LOW DOSE 10 MUG/ML PTX ENHANCED RAS/NFKB SIGNALING, PROLIFERATION, DIFFERENTIATION, AND INFLAMMATION, PARTICULARLY, IT STIMULATED NEUROMUSCULAR AND OSTEOBLASTIC DIFFERENTIATION, INNATE IMMUNITY, AND CELL-MEDIATED IMMUNITY, BUT ATTENUATED ER STRESS, FIBROSIS, ANGIOGENESIS, AND CHRONIC INFLAMMATION, WHILE THE HIGH DOSE 300 MUG/ML PTX WAS FOUND TO ALLEVIATE THE 10 MUG/ML PTX-INDUCED BIOLOGICAL EFFECTS, RESULTED IN THE SUPPRESSION OF RAS/NFKB SIGNALING, PROLIFERATION, NEUROMUSCULAR AND OSTEOBLASTIC DIFFERENTIATION, AND INFLAMMATION. 2022 3 5062 77 PHOSPHATE NIMA-RELATED KINASE 2-DEPENDENT EPIGENETIC PATHWAYS IN DORSAL ROOT GANGLION NEURONS MEDIATES PACLITAXEL-INDUCED NEUROPATHIC PAIN. BACKGROUND: THE MICROTUBULE-STABILIZING DRUG PACLITAXEL (PTX) IS AN IMPORTANT CHEMOTHERAPEUTIC AGENT FOR CANCER TREATMENT AND CAUSES PERIPHERAL NEUROPATHY AS A COMMON SIDE EFFECT THAT SUBSTANTIALLY IMPACTS THE FUNCTIONAL STATUS AND QUALITY OF LIFE OF PATIENTS. THE MECHANISTIC ROLE FOR NIMA-RELATED KINASE 2 (NEK2) IN THE PROGRESSION OF PTX-INDUCED NEUROPATHIC PAIN HAS NOT BEEN ESTABLISHED. METHODS: ADULT MALE SPRAGUE-DAWLEY RATS INTRAPERITONEALLY RECEIVED PTX TO INDUCE NEUROPATHIC PAIN. THE PROTEIN EXPRESSION LEVELS IN THE DORSAL ROOT GANGLION (DRG) OF ANIMALS WERE MEASURED BY BIOCHEMICAL ANALYSES. NOCICEPTIVE BEHAVIORS WERE EVALUATED BY VON FREY TESTS AND HOT PLATE TESTS. RESULTS: PTX INCREASED PHOSPHORYLATION OF THE IMPORTANT MICROTUBULE DYNAMICS REGULATOR NEK2 IN DRG NEURONS AND INDUCED PROFOUND NEUROPATHIC ALLODYNIA. PTX-ACTIVATED PHOSPHORYLATED NEK2 (PNEK2) INCREASED JUMONJI DOMAIN-CONTAINING 3 (JMJD3) PROTEIN, A HISTONE DEMETHYLASE PROTEIN, TO SPECIFICALLY CATALYZE THE DEMETHYLATION OF THE REPRESSIVE HISTONE MARK H3 LYSINE 27 TRIMETHYLATION (H3K27ME3) AT THE TRPV1 GENE, THEREBY ENHANCING TRANSIENT RECEPTOR POTENTIAL VANILLOID SUBTYPE-1 (TRPV1) EXPRESSION IN DRG NEURONS. MOREOVER, THE PNEK2-DEPENDENT PTX RESPONSE PROGRAM IS REGULATED BY ENHANCING P90 RIBOSOMAL S6 KINASE 2 (RSK2) PHOSPHORYLATION. CONVERSELY, INTRATHECAL INJECTIONS OF KAEMPFEROL (A SELECTIVE RSK2 ACTIVATION ANTAGONIST), NCL 00017509 (A SELECTIVE NEK2 INHIBITOR), NEK2-TARGETED SIRNA, GSK-J4 (A SELECTIVE JMJD3 INHIBITOR), OR CAPSAZEPINE (AN ANTAGONIST OF TRPV1 RECEPTOR) INTO PTX-TREATED RATS REVERSED NEUROPATHIC ALLODYNIA AND RESTORED SILENCING OF THE TRPV1 GENE, SUGGESTING THE HIERARCHY AND INTERACTION AMONG PHOSPHORYLATED RSK2 (PRSK2), PNEK2, JMJD3, H3K27ME3, AND TRPV1 IN THE DRG NEURONS IN PTX-INDUCED NEUROPATHIC PAIN. CONCLUSIONS: PRSK2/JMJD3/H3K27ME3/TRPV1 SIGNALING IN THE DRG NEURONS PLAYS AS A KEY REGULATOR FOR PTX THERAPEUTIC APPROACHES. 2023 4 6612 39 ULTRA-LOW-DOSE NALOXONE ENHANCES THE ANTINOCICEPTIVE EFFECT OF MORPHINE IN PTX-TREATED RATS: REGULATION ON GLOBAL HISTONE METHYLATION. OBJECTIVE: EPIGENETIC REPROGRAMMING MAY HAVE A POSSIBLE ROLE IN NEUROPATHIC PAIN DEVELOPMENT; THE PRESENT STUDY EXAMINED THE GLOBAL PATTERNS OF LYSINE HISTONE MODIFICATION. IN THIS SERIAL STUDY WE ANALYZED THE LEVELS OF HISTONE 3 LYSINE 4 MONOMETHYLATION, HISTONE 3 LYSINE 4 DIMETHYLATION, AND HISTONE 3 LYSINE 9 TRIMETHYLATION IN PERTUSSIS TOXIN (PTX)-INDUCED THERMAL HYPERALGESIC RAT SPINAL CORDS. METHODS: MALE WISTAR RATS IMPLANTED WITH AN INTRATHECAL CATHETER RECEIVED A SINGLE INTRATHECAL PTX (1 MUG IN 5 MUL SALINE) INJECTION. FOUR DAYS LATER, THEY WERE RANDOMLY ASSIGNED TO RECEIVE EITHER A SINGLE INJECTION OF SALINE, OR ULTRA-LOW-DOSE NALOXONE (15 NG IN 5 MUL SALINE), FOLLOWED BY MORPHINE (10 MUG IN 5 MUL SALINE) INJECTION 30 MINUTES LATER. RESULTS: THE RESULTS SHOWED THAT PTX INJECTION INDUCED THERMAL HYPERALGESIA AND SIGNIFICANT INCREASE OF GLOBAL HISTONE METHYLATION IN THE SPINAL CORDS. INTRATHECAL MORPHINE ALONE DID NOT AFFECT THE THERMAL HYPERALGESIA AND GLOBAL HISTONE METHYLATION. IN CONTRAST, INTRATHECAL ADMINISTRATION OF ULTRA-LOW-DOSE NALOXONE PLUS MORPHINE SIGNIFICANTLY ATTENUATED THE PTX-INDUCED THERMAL HYPERALGESIA AND DOWN-REGULATED THE GLOBAL HISTONE METHYLATION. CONCLUSION: THE RESULTS SUGGEST THAT ULTRA-LOW-DOSE NALOXONE MIGHT BE CLINICAL VALUABLE FOR NEUROPATHIC PAIN MANAGEMENT VIA REGULATING GLOBAL HISTONE MODIFICATION. 2012 5 5784 30 SPONTANEOUS FIRING AS AN EPIGENETIC FACTOR IN BRAIN DEVELOPMENT--PHYSIOLOGICAL CONSEQUENCES OF CHRONIC TETRODOTOXIN AND PICROTOXIN EXPOSURE ON CULTURED RAT NEOCORTEX NEURONS. FUNCTIONAL CONSEQUENCES OF EITHER SUPPRESSING OR INTENSIFYING SPONTANEOUS NEURONAL FIRING HAVE BEEN STUDIED IN DEVELOPING RAT CEREBRAL CORTEX CULTURES USING, RESPECTIVELY, TETRODOTOXIN (TTX) AND PICROTOXIN (PTX) ADDED CHRONICALLY TO THE GROWTH MEDIUM. SIMPLE MEASURES DERIVED FROM THE INTERSPIKE INTERVAL HISTOGRAM WERE ABLE TO POWERFULLY DISCRIMINATE BETWEEN AGE AND TREATMENT GROUPS. AFTER RETURN TO CONTROL MEDIUM, MOST TTX-TREATED NEURONS SPONTANEOUSLY DISPLAYED STEREOTYPED CLUSTERING OF ACTION POTENTIALS ('PHASIC' FIRING) WHICH CLOSELY RESEMBLED THE CHARACTERISTIC FIRING PATTERNS SEEN ACUTELY IN THE PRESENCE OF PTX. THE 'TTX-SYNDROME' THUS SUGGESTS THAT GABAERGIC SYNAPTIC INHIBITION IS INEFFECTIVE IN CORTICAL NETWORKS GROWN UNDER CONDITIONS WHICH PREVENT THE EXPRESSION OF BIOELECTRIC ACTIVITY. IN CONTRAST, AFTER RETURN TO CONTROL MEDIUM, NEURONS WHICH HAD BEEN PARTIALLY DISINHIBITED THROUGHOUT DEVELOPMENT (BY CONTINUOUS EXPOSURE TO PTX) HAD EVEN LESS PHASIC FIRING THAN WAS MEASURED IN AGE-MATCHED CONTROLS. BASED UPON THESE AND PREVIOUS FINDINGS, A TWO (MAIN) FACTOR MODEL IS PUT FORTH WHICH CAN ECONOMICALLY ACCOUNT FOR THE MAJOR EFFECTS. THE WORKING HYPOTHESIS EMBODIED IN THIS MODEL IS THAT PHASIC NEURONAL DISCHARGES NOT ONLY ACCELERATE THE MATURATION OF EXCITATORY CONNECTIONS WITHIN THE NEOCORTEX BUT, EVEN MORE IMPORTANT, ARE CRUCIAL FOR THE DEVELOPMENT OF ADEQUATE INHIBITORY SYNAPTIC TRANSMISSION. 1992 6 5480 38 RESVERATROL REVERSES MORPHINE-INDUCED NEUROINFLAMMATION IN MORPHINE-TOLERANT RATS BY REVERSAL HDAC1 EXPRESSION. BACKGROUND/PURPOSE: WE PREVIOUSLY SHOWED THAT SUBSEQUENT INTRATHECAL (I.T.) INJECTION OF RESVERATROL (30 MUG) SIGNIFICANTLY REVERSES MORPHINE-EVOKED NEUROINFLAMMATION IN MORPHINE-TOLERANT RATS. THE PRESENT STUDY EXAMINED THE UNDERLYING MECHANISM. METHODS: MALE WISTAR RATS WERE IMPLANTED WITH TWO I.T. CATHETERS, ONE OF WHICH WAS CONNECTED TO A MINIOSMOTIC PUMP AND USED FOR MORPHINE (15 MUG/H) OR SALINE INFUSION FOR 120 HOURS. TO EXAMINE THE EFFECTS ON SPINAL CORD EXPRESSION OF HISTONE DEACETYLASE 1 (HDAC1), THE INFLAMMATORY CYTOKINE TUMOR NECROSIS FACTOR-ALPHA (TNF-ALPHA), AND TNF RECEPTOR (TNFR) 1 AND TNFR2 DURING TOLERANCE INDUCTION, A TAIL-FLICK TEST WAS PERFORMED PRIOR TO INFUSION AND AFTER 24 HOURS, 48 HOURS, 72 HOURS, 96 HOURS, AND 120 HOURS OF INFUSION. RESULTS: RESVERATROL TREATMENT PRIOR TO MORPHINE CHALLENGE RESTORED THE ANTINOCICEPTIVE EFFECT OF MORPHINE IN MORPHINE-TOLERANT RATS AND REVERSED THE MORPHINE INFUSION-INDUCED INCREASE IN HDAC1, TNF-ALPHA, AND TNFR1 EXPRESSION. MOREOVER, CHRONIC MORPHINE INFUSION INCREASED TNFR1-SPECIFIC EXPRESSION IN NEURON IN MORPHINE-TOLERANT RAT SPINAL CORDS, AND THIS EFFECT WAS ALMOST COMPLETELY INHIBITED BY RESVERATROL TREATMENT PRIOR TO MORPHINE CHALLENGE. CONCLUSION: RESVERATROL RESTORES THE ANTINOCICEPTIVE EFFECT OF MORPHINE BY REVERSING MORPHINE INFUSION-INDUCED SPINAL CORD NEUROINFLAMMATION AND INCREASE IN TNFR1 EXPRESSION. THE REVERSAL OF THE MORPHINE-INDUCED INCREASE IN TNFR1 EXPRESSION BY RESVERATROL IS PARTIALLY DUE TO REVERSAL OF THE MORPHINE INFUSION-INDUCED INCREASE IN HDAC1 EXPRESSION. RESVERATROL PRETREATMENT CAN BE USED AS AN ADJUVANT IN CLINICAL PAIN MANAGEMENT FOR PATIENTS WHO NEED LONG-TERM MORPHINE TREATMENT OR WITH NEUROPATHIC PAIN. 2016 7 5020 37 PERSISTENT OVEREXPRESSION OF DNA METHYLTRANSFERASE 1 ATTENUATING GABAERGIC INHIBITION IN BASOLATERAL AMYGDALA ACCOUNTS FOR ANXIETY IN RAT OFFSPRING EXPOSED PERINATALLY TO LOW-DOSE BISPHENOL A. SUBSTANTIAL EVIDENCE INDICATES THAT PREDISPOSITION TO DISEASES CAN BE ACQUIRED DURING EARLY STAGES OF DEVELOPMENT AND INTERACTIONS BETWEEN ENVIRONMENTAL AND GENETIC FACTORS MAY BE IMPLICATED IN THE ONSET OF MANY PATHOLOGICAL CONDITIONS. WE HAVE SHOWN THAT PERINATAL EXPOSURE TO BISPHENOL A (BPA) AT ENVIRONMENTAL DOSE LEVEL CAUSES LONG-TERM ANXIETY-LIKE BEHAVIORS IN RATS. THE AIM OF THIS STUDY WAS TO EXAMINE EPIGENETIC REPROGRAMMING EFFECT OF BPA ON ANXIETY-RELATED NEUROBEHAVIOR IN THE RAT OFFSPRING. THE RESULTS OF REAL-TIME RT-PCR DISPLAYED THAT THE OVEREXPRESSION OF DNA METHYLTRANSFERASE 1 (DNMT1) MRNA WAS ACCOMPANIED BY THE REDUCTION OF GLUTAMIC ACID DECARBOXYLASE 67 (GAD67) MRNA LEVEL IN THE BASOLATERAL AMYGDALA (BLA) OF POSTNATAL DAY 45 BPA-EXPOSED FEMALE RATS. CHRONIC INTRO-BLA INJECTION WITH 5-ADA-CDR COULD RECTIFY THE GAD67 MRNA EXPRESSION. BEHAVIORAL DATA SHOWED THAT THE ANXIETY-LIKE BEHAVIORS IN BPA-EXPOSED RATS WERE REVERSED BY INTRO-BLA TREATMENT WITH 5-ADA-CDR WHICH COULD BE FURTHER BLOCKED BY PTX. ELECTROPHYSIOLOGICAL STUDY REVEALED BEHAVIORAL ALTERATIONS WERE ASSOCIATED WITH THE INCREASE OF POSTSYNAPTIC NEURONAL EXCITABILITY IN THE CORTICAL-BLA PATHWAY WHICH APPEARED AS MULTISPIKE RESPONSES, PAIRED-PULSE FACILITATION INSTEAD OF PAIRED-PULSE INHIBITION AND LONG-TERM POTENTIATION AND 5-AZA-CDR TREATMENT RESTORED THE INCREASED SYNAPTIC TRANSMISSION IN THE BLA VIA IMPROVING GABAERGIC SYSTEM. THE ABOVE RESULTS SUGGEST THAT THE OVEREXPRESSION OF DNMT1 IN THE BLA IS RESPONSIBLE FOR THE ETIOLOGY OF ANXIETY ASSOCIATED WITH BPA EXPOSURE VIA GABAERGIC DISINHIBITION. IN ADDITION, WE ALSO FIND THESE LONG-TERM NEUROBEHAVIORAL EFFECTS OF DEVELOPMENTAL BPA EXPOSURE ARE REVERSIBLE IN ADOLESCENT PERIOD. 2013 8 4699 45 NFATC2-DEPENDENT EPIGENETIC UPREGULATION OF CXCL14 IS INVOLVED IN THE DEVELOPMENT OF NEUROPATHIC PAIN INDUCED BY PACLITAXEL. BACKGROUND: THE MAJOR DOSE-LIMITING TOXICITY OF PACLITAXEL, ONE OF THE MOST COMMONLY USED DRUGS TO TREAT SOLID TUMOR, IS PAINFUL NEUROPATHY. HOWEVER, THE MOLECULAR MECHANISMS UNDERLYING PACLITAXEL-INDUCED PAINFUL NEUROPATHY ARE LARGELY UNCLARIFIED. METHODS: PAW WITHDRAWAL THRESHOLD WAS MEASURED IN THE RATS FOLLOWING INTRAPERITONEAL INJECTION OF PACLITAXEL. THE QPCR, WESTERN BLOTTING, PROTEIN OR CHROMATIN IMMUNOPRECIPITATION, CHIP-SEQ IDENTIFICATION OF NFATC2 BINDING SITES, AND MICROARRAY ANALYSIS WERE PERFORMED TO EXPLORE THE MOLECULAR MECHANISM. RESULTS: WE FOUND THAT PACLITAXEL TREATMENT INCREASED THE NUCLEAR EXPRESSION OF NFATC2 IN THE SPINAL DORSAL HORN, AND KNOCKDOWN OF NFATC2 WITH NFATC2 SIRNA SIGNIFICANTLY ATTENUATED THE MECHANICAL ALLODYNIA INDUCED BY PACLITAXEL. FURTHER BINDING SITE ANALYSIS UTILIZING CHIP-SEQ ASSAY COMBINING WITH GENE EXPRESSION PROFILE REVEALED A SHIFT OF NFATC2 BINDING SITE CLOSER TO TTS OF TARGET GENES IN DORSAL HORN AFTER PACLITAXEL TREATMENT. WE FURTHER FOUND THAT NFATC2 OCCUPANCY MAY DIRECTLY UPREGULATE THE CHEMOKINE CXCL14 EXPRESSION IN DORSAL HORN, WHICH WAS MEDIATED BY ENHANCED INTERACTION BETWEEN NFATC2 AND P300 AND CONSEQUENTLY INCREASED ACETYLATION OF HISTONE H4 IN CXCL14 PROMOTER REGION. ALSO, KNOCKDOWN OF CXCL14 IN DORSAL HORN SIGNIFICANTLY ATTENUATED MECHANICAL ALLODYNIA INDUCED BY PACLITAXEL. CONCLUSION: THESE RESULTS SUGGESTED THAT ENHANCED INTERACTION BETWEEN P300 AND NFATC2 MEDIATED THE EPIGENETIC UPREGULATION OF CXCL14 IN THE SPINAL DORSAL HORN, WHICH CONTRIBUTED TO THE CHEMOTHERAPEUTIC PACLITAXEL-INDUCED CHRONIC PAIN. 2020 9 743 40 CANNABINOID TYPE 2 RECEPTOR SYSTEM MODULATES PACLITAXEL-INDUCED MICROGLIAL DYSREGULATION AND CENTRAL SENSITIZATION IN RATS. PACLITAXEL INDUCES MICROGLIAL ACTIVATION AND PRODUCTION OF PROINFLAMMATORY MEDIATORS IN THE DORSAL HORN, WHICH CONTRIBUTE TO THE DEVELOPMENT AND MAINTENANCE OF CENTRAL SENSITIZATION AND PAIN BEHAVIOR. MDA7, 1-([3-BENZYL-3-METHYL-2,3-DIHYDRO-1-BENZOFURAN-6-YL]CARBONYL) PIPERIDINE, IS A NOVEL HIGHLY SELECTIVE CANNABINOID TYPE 2 (CB2) AGONIST. WE TESTED THE HYPOTHESIS THAT ACTIVATION OF CB2 RECEPTOR BY MDA7 MODULATES MICROGLIAL DYSREGULATION, SUPPRESSES THE OVEREXPRESSION OF BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) IN MICROGLIA IN THE DORSAL HORN, AND ATTENUATES THE CENTRAL SENSITIZATION AND PAIN BEHAVIOR INDUCED BY PACLITAXEL. FOR 4 CONSECUTICE DAYS, GROUPS OF RATS RANDOMLY RECEIVED SALINE OR 1.0 MG/KG OF PACLITAXEL DAILY INTRAPERITONEALLY FOR A TOTAL CUMULATIVE DOSE OF 4 MG/KG. MDA7 15 MG/KG INTRAPERITONEALLY OR VEHICLE WERE ADMINISTERED 15 MIN BEFORE ADMINISTERING PACLITAXEL FOR 4 DAYS AND THEN CONTINUED FOR ANOTHER 10 DAYS. BEHAVIORAL AND MOLECULAR STUDIES WERE PERFORMED. PACLITAXEL INDUCED THE EXPRESSION OF CB2 RECEPTORS AND PRODUCTION OF INTERLEUKIN (IL)-6 IN MICROGLIA IN THE DORSAL HORN. MDA7 ATTENUATED THE EXPRESSION OF IL-6 AND PROMOTED THE EXPRESSION OF IL-10. PACLITAXEL INDUCED EPIGENETIC UPREGULATION OF IRF8 AND P2X PURINOCEPTOR 4 (P2X4) IN MICROGLIA AND SUBSEQUENTLY INCREASED THE EXPRESSION OF ALPHA ISOFORM OF CALCIUM/CALMODULIN-DEPENDENT PROTEIN KINASE II (CAMKIIALPHA), TRANSCRIPTIONAL FACTORS P-CREB AND DELTAFOSB, LEADING TO THE OVERPRODUCTION OF BDNF IN MICROGLIA. PACLITAXEL ALSO UPREGULATED THE EXPRESSION OF GLUTAMATE RECEPTOR SUBUNITS GLUR1 AND NR2B, DECREASED THE EXPRESSION OF K(+)-CL(-) COTRANSPORTER, AND INDUCED MECHANICAL ALLODYNIA IN RATS. ALL OF THE AFOREMENTIONED MOLECULAR CHANGES WERE ATTENUATED BY MDA7. OUR DATA SHOW THAT MDA7 ATTENUATED PACLITAXEL-INDUCED MOLECULAR AND BEHAVIORAL CHANGES IN RATS. PERSPECTIVE: THIS STUDY PROVIDES EVIDENCE THAT PACLITAXEL INDUCED MICROGLIA DYSREGULATION AND EPIGENETICALLY UPREGULATED THE MICROGLIAL EXPRESSION OF BDNF, WHICH LED TO SENSITIZATION OF DORSAL HORN NEURONS AND MECHANICAL ALLODYNIA IN RATS. THE CB2 AGONIST MDA7 ALLEVIATED THESE PATHOLOGICAL PROCESSES. MDA7 REPRESENTS AN INNOVATIVE THERAPEUTIC APPROACH FOR TREATMENT OF CHEMOTHERAPY-INDUCED NEUROPATHY. 2019 10 2321 45 EPIGENETIC REGULATION OF GENES THAT MODULATE CHRONIC STRESS-INDUCED VISCERAL PAIN IN THE PERIPHERAL NERVOUS SYSTEM. BACKGROUND & AIMS: CHRONIC STRESS ALTERS THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS, INCREASES GUT MOTILITY, AND INCREASES THE PERCEPTION OF VISCERAL PAIN. WE INVESTIGATED WHETHER EPIGENETIC MECHANISMS REGULATE CHRONIC STRESS-INDUCED VISCERAL PAIN IN THE PERIPHERAL NERVOUS SYSTEMS OF RATS. METHODS: MALE RATS WERE SUBJECTED TO 1 HOUR OF WATER AVOIDANCE STRESS EACH DAY, OR GIVEN DAILY SUBCUTANEOUS INJECTIONS OF CORTICOSTERONE, FOR 10 CONSECUTIVE DAYS. L4-L5 AND L6-S2 DORSAL ROOT GANGLIA (DRG) WERE COLLECTED AND COMPARED BETWEEN STRESSED AND CONTROL RATS (PLACED FOR 1 HOUR EACH DAY IN A TANK WITHOUT WATER). LEVELS OF CANNABINOID RECEPTOR 1 (CNR1), DNA (CYTOSINE-5-)-METHYLTRANSFERASE 1 (DNMT1), TRANSIENT RECEPTOR POTENTIAL VANILLOID TYPE 1 (TRPV1), AND EP300 WERE KNOCKED DOWN IN DRG NEURONS IN SITU WITH SMALL INTERFERING RNAS. WE MEASURED DNA METHYLATION AND HISTONE ACETYLATION AT GENES ENCODING THE GLUCOCORTICOID RECEPTOR (NR3C1), CNR1, AND TRPV1. VISCERAL PAIN WAS MEASURED IN RESPONSE TO COLORECTAL DISTENTION. RESULTS: CHRONIC STRESS WAS ASSOCIATED WITH INCREASED METHYLATION OF THE NR3C1 PROMOTER AND REDUCED EXPRESSION OF THIS GENE IN L6-S2, BUT NOT L4-L5, DRGS. STRESS ALSO WAS ASSOCIATED WITH UP-REGULATION IN DNMT1-ASSOCIATED METHYLATION OF THE CNR1 PROMOTER AND DOWN-REGULATION OF GLUCOCORTICOID-RECEPTOR-MEDIATED EXPRESSION OF CNR1 IN L6-S2, BUT NOT L4-L5, DRGS. CONCURRENTLY, CHRONIC STRESS INCREASED EXPRESSION OF THE HISTONE ACETYLTRANSFERASE EP300 AND INCREASED HISTONE ACETYLATION AT THE TRPV1 PROMOTER AND EXPRESSION OF THE TRPV1 RECEPTOR IN L6-S2 DRG NEURONS. KNOCKDOWN OF DNMT1 AND EP300 IN L6-S2 DRG NEURONS OF RATS REDUCED DNA METHYLATION AND HISTONE ACETYLATION, RESPECTIVELY, AND PREVENTED CHRONIC STRESS-INDUCED INCREASES IN VISCERAL PAIN. CONCLUSIONS: CHRONIC STRESS INCREASES DNA METHYLATION AND HISTONE ACETYLATION OF GENES THAT REGULATE VISCERAL PAIN SENSATION IN THE PERIPHERAL NERVOUS SYSTEM OF RATS. BLOCKING EPIGENETIC REGULATORY PATHWAYS IN SPECIFIC REGIONS OF THE SPINAL CORD MIGHT BE DEVELOPED TO TREAT PATIENTS WITH CHRONIC ABDOMINAL PAIN. 2015 11 742 47 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 2452 41 EPIGENETIC SUPPRESSION OF POTASSIUM-CHLORIDE CO-TRANSPORTER 2 EXPRESSION IN INFLAMMATORY PAIN INDUCED BY COMPLETE FREUND'S ADJUVANT (CFA). BACKGROUND: MULTIPLE MECHANISMS CONTRIBUTE TO THE STIMULUS-EVOKED PAIN HYPERSENSITIVITY THAT MAY BE EXPERIENCED AFTER PERIPHERAL INFLAMMATION. PERSISTENT PATHOLOGICAL STIMULI IN MANY PAIN CONDITIONS AFFECT THE EXPRESSION OF CERTAIN GENES THROUGH EPIGENETIC ALTERNATIONS. THE MAIN PURPOSE OF OUR STUDY WAS TO INVESTIGATE THE ROLE OF EPIGENETIC MODIFICATION ON POTASSIUM-CHLORIDE CO-TRANSPORTER 2 (KCC2) GENE EXPRESSION IN THE PERSISTENCE OF INFLAMMATORY PAIN. METHODS: PERSISTENT INFLAMMATORY PAIN WAS INDUCED THROUGH THE INJECTION OF COMPLETE FREUND'S ADJUVANT (CFA) IN THE LEFT HIND PAW OF RATS. ACETYL-HISTONE H3 AND H4 LEVEL WAS DETERMINED BY CHROMATIN IMMUNOPRECIPITATION IN THE SPINAL DORSAL HORN. PAIN BEHAVIOUR AND INHIBITORY SYNAPTIC FUNCTION OF SPINAL CORD WERE DETERMINED BEFORE AND AFTER CFA INJECTION. KCC2 EXPRESSION WAS DETERMINED BY REAL TIME RT-PCR AND WESTERN BLOT. INTRATHECAL KCC2 SIRNA (2 MUG PER 10 MUL PER RAT) OR HDAC INHIBITOR (10 MUG PER 10 MUL PER RAT) WAS INJECTED ONCE DAILY FOR 3 DAYS BEFORE CFA INJECTION. RESULTS: PERSISTENT INFLAMMATORY PAIN EPIGENETICALLY SUPPRESSED KCC2 EXPRESSION THROUGH HISTONE DEACETYLASE (HDAC)-MEDIATED HISTONE HYPOACETYLATION, RESULTING IN DECREASED INHIBITORY SIGNALLING EFFICACY. KCC2 KNOCK-DOWN CAUSED BY INTRATHECAL ADMINISTRATION OF KCC2 SIRNA IN NAIVE RATS REDUCED KCC2 EXPRESSION IN THE SPINAL CORD, LEADING TO SENSITIZED PAIN BEHAVIOURS AND IMPAIRED INHIBITORY SYNAPTIC TRANSMISSION IN THEIR SPINAL CORDS. MOREOVER, INTRATHECAL HDAC INHIBITOR INJECTION IN CFA RATS INCREASED KCC2 EXPRESSION, PARTIALLY RESTORING THE SPINAL INHIBITORY SYNAPTIC TRANSMISSION AND RELIEVING THE SENSITIZED PAIN BEHAVIOUR. CONCLUSION: THESE FINDINGS SUGGEST THAT THE TRANSCRIPTION OF SPINAL KCC2 IS REGULATED BY HISTONE ACETYLATION EPIGENETICALLY FOLLOWING CFA. SIGNIFICANCE: PERSISTENT PAIN SUPPRESSES KCC2 EXPRESSION THROUGH HDAC-MEDIATED HISTONE HYPOACETYLATION AND CONSEQUENTLY IMPAIRS THE INHIBITORY FUNCTION OF INHIBITORY INTERNEURONS. DRUGS SUCH AS HDAC INHIBITORS THAT SUPPRESS THE INFLUENCES OF PERSISTENT PAIN ON THE EXPRESSION OF KCC2 MAY SERVE AS A NOVEL ANALGESIC. 2017 13 2751 41 EXPRESSION OF ACETYL-HISTONE H3 AND ACETYL-HISTONE H4 IN DORSAL ROOT GANGLION AND SPINAL DORSAL HORN IN RAT CHRONIC PAIN MODELS. AIMS: HISTONE ACETYLATION AND DEACETYLATION ARE TWO HISTONE POSTTRANSLATIONAL MODIFICATIONS THAT ARE USUALLY CONTROLLED BY HISTONE ACETYLTRANSFERASES (HATS) AND HISTONE DEACETYLASES (HDACS). ALTHOUGH HATS OR HDACS INHIBITORS COULD RELIEVE PAIN HYPERSENSITIVITIES IN CHRONIC PAIN ANIMAL MODELS, IT IS NOT CLEAR ON THE EXPRESSION OF GLOBAL HISTONE ACETYLATION IN THE DORSAL ROOT GANGLION (DRG) OR SPINAL DORSAL HORN IN CHRONIC PAIN CONDITIONS. MAIN METHODS: A SPINAL NERVE LIGATION (SNL)-INDUCED NEUROPATHIC PAIN MODEL AND A COMPLETE FREUND'S ADJUVANT (CFA)-INDUCED INFLAMMATORY PAIN MODEL IN RATS WERE USED TO EXAMINE THE EXPRESSION OF TOTAL ACETYL-HISTONE H3 (ACH3) AND TOTAL ACETYL-HISTONE H4 (ACH4) BY IMMUNOFLUORESCENCE OR WESTERN BLOT. KEY FINDINGS: ACH3 AND ACH4 NOT ONLY LOCALIZED IN NEURONAL NUCLEI, BUT ALSO IN NUCLEI OF GLIAL CELLS IN THE DRG. UNILATERAL SNL INDUCED THE INCREASE OF ACH3 AND ACH4 EXPRESSION IN THE INJURED LUMBAR 5 (L5) DRG, BUT NOT IN THE UNINJURED L5 DRG OR THE SPINAL DORSAL HORN, WHILE UNILATERAL INTRAPLANTAR INJECTION OF CFA INCREASED ACH3 AND ACH4 EXPRESSION IN THE IPSILATERAL L4/5 SPINAL DORSAL HORN, BUT NOT IN THE L4/5 DRG. SIGNIFICANCE: THESE RESULTS PROVIDE MORPHOLOGICAL EVIDENCE FOR GLOBAL HISTONE ACETYLATION EXPRESSION IN THE DRG AND SPINAL CORD AND INDICATE THE DIFFERENTIAL EXPRESSION IN THE DRG AND SPINAL DORSAL HORN IN DIFFERENT CHRONIC PAIN MODELS. MORE PRECISE EPIGENETIC MECHANISMS OF HISTONE ACETYLATION ON THE TARGET GENES NEED TO BE REVEALED. 2018 14 5657 37 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 15 4616 42 NERVE INJURY INCREASES BRAIN-DERIVED NEUROTROPHIC FACTOR LEVELS TO SUPPRESS BK CHANNEL ACTIVITY IN PRIMARY SENSORY NEURONS. ABNORMAL HYPEREXCITABILITY OF PRIMARY SENSORY NEURONS CONTRIBUTES TO NEUROPATHIC PAIN DEVELOPMENT AFTER NERVE INJURY. NERVE INJURY PROFOUNDLY REDUCES THE EXPRESSION OF BIG CONDUCTANCE CA(2+) -ACTIVATED K(+) (BK) CHANNELS IN THE DORSAL ROOT GANGLION (DRG). HOWEVER, LITTLE IS KNOWN ABOUT HOW NERVE INJURY AFFECTS BK CHANNEL ACTIVITY IN DRG NEURONS. IN THIS STUDY, WE DETERMINED THE CHANGES IN BK CHANNEL ACTIVITY IN DRG NEURONS IN A RAT MODEL OF NEUROPATHIC PAIN AND THE CONTRIBUTION OF BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) TO REDUCED BK CHANNEL ACTIVITY. THE BK CHANNEL ACTIVITY WAS PRESENT PREDOMINANTLY IN SMALL AND MEDIUM DRG NEURONS, AND LIGATION OF L5 AND L6 SPINAL NERVES PROFOUNDLY DECREASED THE BK CURRENT DENSITY IN THESE NEURONS. BLOCKING BK CHANNELS SIGNIFICANTLY INCREASED NEURONAL EXCITABILITY IN SHAM CONTROL, BUT NOT IN NERVE-INJURED, RATS. THE BDNF CONCENTRATION IN THE DRG WAS SIGNIFICANTLY GREATER IN NERVE-INJURED RATS THAN IN CONTROL RATS. BDNF TREATMENT LARGELY REDUCED BK CURRENTS IN DRG NEURONS IN CONTROL RATS, WHICH WAS BLOCKED BY EITHER ANTI-BDNF ANTIBODY OR K252A, A TRK RECEPTOR INHIBITOR. FURTHERMORE, EITHER ANTI-BDNF ANTIBODY OR K252A REVERSED REDUCTION IN BK CURRENTS IN INJURED DRG NEURONS. BDNF TREATMENT REDUCED THE MRNA LEVELS OF BKALPHA1 SUBUNIT IN DRG NEURONS, AND ANTI-BDNF ANTIBODY ATTENUATED THE REDUCTION IN THE BKALPHA1 MRNA LEVEL IN INJURED DRG NEURONS. THESE FINDINGS SUGGEST THAT NERVE INJURY PRIMARILY DIMINISHES THE BK CHANNEL ACTIVITY IN SMALL AND MEDIUM DRG NEURONS. INCREASED BDNF LEVELS CONTRIBUTE TO REDUCED BK CHANNEL ACTIVITY IN DRG NEURONS THROUGH EPIGENETIC AND TRANSCRIPTIONAL MECHANISMS IN NEUROPATHIC PAIN. 2012 16 1320 39 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 17 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 18 5976 37 TET1-DEPENDENT EPIGENETIC MODIFICATION OF BDNF EXPRESSION IN DORSAL HORN NEURONS MEDIATES NEUROPATHIC PAIN IN RATS. TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE 1 (TET1) MEDIATES THE CONVERSION OF 5-METHYLCYTOSINE (5 MC) TO 5-HYDROXYMETHYLCYTOSINE (5 HMC), HENCE PROMOTING DNA DEMETHYLATION. ALTHOUGH RECENT STUDIES HAVE LINKED THE DNA DEMETHYLATION OF SPECIFIC GENES TO PAIN HYPERSENSITIVITY, THE ROLE OF SPINAL TET1-DEPENDENT DNA DEMETHYLATION IN NOCICEPTION HYPERSENSITIVITY DEVELOPMENT REMAINS ELUSIVE. HERE, WE REPORT CORRELATED WITH BEHAVIORAL ALLODYNIA, SPINAL NERVE LIGATION (SNL) UPREGULATED TET1 EXPRESSION IN DORSAL HORN NEURONS THAT HYDROXYLATE 5 MC TO 5 HMC AT CPG DINUCLEOTIDES IN THE BDNF PROMOTER TO PROMOTE SPINAL BDNF EXPRESSION AT DAY 7 AFTER OPERATION. FOCAL KNOCKDOWN OF SPINAL TET1 EXPRESSION DECREASED TET1 BINDING AND 5 HMC ENRICHMENT, FURTHER INCREASED 5 MC ENRICHMENT AT CPG SITES IN THE BDNF PROMOTER AND DECREASED SPINAL BDNF EXPRESSION ACCOMPANIED BY THE ALLEVIATION OF THE DEVELOPED ALLODYNIA. MOREOVER, AT DAY 7 AFTER OPERATION, SNL-ENHANCED TET1 EXPRESSION ALSO INHIBITED THE BINDING OF DNA METHYLTRANSFERASES (DNMTS, I.E., DNMT1, DNMT3A, AND DNMT3B) TO THE BDNF PROMOTER, A REQUIREMENT FOR TRANSCRIPTIONAL SILENCING BY CATALYSING 5-CYTOSINE (5C) TO 5 MC. TOGETHER, THESE DATA SUGGEST AT CPG SITES OF THE BDNF PROMOTER, SNL-ENHANCED TET1 EXPRESSION PROMOTES DNA DEMETHYLATION BOTH BY CONVERTING 5 MC TO 5 HMC AND INHIBITING DNMT BINDING TO REGULATE SPINAL BDNF EXPRESSION, HENCE CONTRIBUTING TO BEHAVIORAL ALLODYNIA DEVELOPMENT. 2016 19 4172 37 MELATONIN IMPEDES TET1-DEPENDENT MGLUR5 PROMOTER DEMETHYLATION TO RELIEVE PAIN. MELATONIN (N-ACETYL-5-METHOXYTRYPTAMINE)/MT2 RECEPTOR-DEPENDENT EPIGENETIC MODIFICATION REPRESENTS A NOVEL PATHWAY IN THE TREATMENT OF NEUROPATHIC PAIN. BECAUSE SPINAL TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE 1 (TET1)-DEPENDENT EPIGENETIC DEMETHYLATION HAS RECENTLY BEEN LINKED TO PAIN HYPERSENSITIVITY, WE HYPOTHESIZED THAT MELATONIN/MT2-DEPENDENT ANALGESIA INVOLVES SPINAL TET1-DEPENDENT DEMETHYLATION. HERE, WE SHOWED THAT SPINAL TET1 GENE TRANSFER BY INTRATHECAL DELIVERY OF TET1-ENCODING VECTORS TO NAIVE RATS PRODUCED PROFOUND AND LONG-LASTING NOCICEPTIVE HYPERSENSITIVITY. IN ADDITION, ENHANCED TET1 EXPRESSION, TET1-METABOTROPIC GLUTAMATE RECEPTOR SUBTYPE 5 (MGLUR5) PROMOTER COUPLING, DEMETHYLATION AT THE MGLUR5 PROMOTER, AND MGLUR5 EXPRESSION IN DORSAL HORN NEURONS WERE OBSERVED. RATS SUBJECTED TO SPINAL NERVE LIGATION AND INTRAPLANTAR COMPLETE FREUND'S ADJUVANT INJECTION DISPLAYED TACTILE ALLODYNIA AND BEHAVIORAL HYPERALGESIA ASSOCIATED WITH SIMILAR CHANGES IN THE DORSAL HORN. NOTABLY, INTRATHECAL MELATONIN INJECTION REVERSED THE PROTEIN EXPRESSION, PROTEIN-PROMOTER COUPLING, PROMOTER DEMETHYLATION, AND PAIN HYPERSENSITIVITY INDUCED BY TET1 GENE TRANSFER, SPINAL NERVE LIGATION, AND INTRAPLANTAR COMPLETE FREUND'S ADJUVANT INJECTION. ALL THE EFFECTS CAUSED BY MELATONIN WERE BLOCKED BY PRETREATMENT WITH A MT2 RECEPTOR-SELECTIVE ANTAGONIST. IN CONCLUSION, MELATONIN RELIEVES PAIN BY IMPEDING TET1-DEPENDENT DEMETHYLATION OF MGLUR5 IN DORSAL HORN NEURONS THROUGH THE MT2 RECEPTOR. OUR FINDINGS LINK MELATONIN/MT2 SIGNALING TO TET1-DEPENDENT EPIGENETIC DEMETHYLATION OF NOCICEPTIVE GENES FOR THE FIRST TIME AND SUGGEST MELATONIN AS A PROMISING THERAPY FOR THE TREATMENT OF PAIN. 2017 20 2300 45 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