1 2006 120 EPIGENETIC AUGMENTATION OF THE MACROPHAGE INFLAMMATORY PROTEIN 2/C-X-C CHEMOKINE RECEPTOR TYPE 2 AXIS THROUGH HISTONE H3 ACETYLATION IN INJURED PERIPHERAL NERVES ELICITS NEUROPATHIC PAIN. ALTHOUGH THERE IS GROWING EVIDENCE SHOWING THAT THE INVOLVEMENT OF CHEMOKINES IN THE PATHOGENESIS OF NEUROPATHIC PAIN IS ASSOCIATED WITH NEUROINFLAMMATION, THE DETAILS ARE UNCLEAR. WE INVESTIGATED THE C-X-C CHEMOKINE LIGAND TYPE 2 [MACROPHAGE INFLAMMATORY PROTEIN 2 (MIP-2)]/C-X-C CHEMOKINE RECEPTOR TYPE 2 (CXCR2) AXIS AND EPIGENETIC REGULATION OF THESE MOLECULES IN NEUROPATHIC PAIN AFTER PERIPHERAL NERVE INJURY. EXPRESSION OF MIP-2 AND CXCR2 WERE UP-REGULATED AND LOCALIZED ON ACCUMULATED NEUTROPHILS AND MACROPHAGES IN THE INJURED SCIATIC NERVE (SCN) AFTER PARTIAL SCIATIC NERVE LIGATION (PSL). PERINEURAL INJECTION OF MIP-2-NEUTRALIZING ANTIBODY (ANTI-MIP-2) OR THE CXCR2 ANTAGONIST N-(2-BROMOPHENYL)-N'-(2-HYDROXY-4-NITROPHENYL)UREA (SB225002) PREVENTED PSL-INDUCED TACTILE ALLODYNIA AND THERMAL HYPERALGESIA. PERINEURAL INJECTION OF RECOMBINANT MIP-2 ELICITED NEUROPATHIC PAIN-LIKE BEHAVIORS. ANTI-MIP-2 SUPPRESSED NEUTROPHIL ACCUMULATION IN THE SCN AFTER PSL. NEUTROPHIL DEPLETION BY INTRAPERITONEAL INJECTION OF LY6G ANTIBODY ATTENUATED PSL-INDUCED NEUROPATHIC PAIN. BOTH ANTI-MIP-2 AND SB225002 SUPPRESSED UP-REGULATION OF INFLAMMATORY CYTOKINES AND CHEMOKINES IN THE INJURED SCN. IN ADDITION, ACETYLATION OF HISTONE H3 [LYSINE (LYS9)-ACETYLATED HISTONE H3 (ACK9-H3)] ON THE PROMOTER REGION OF MIP-2 AND CXCR2 WAS INCREASED IN THE INJURED SCN AFTER PSL. EXPRESSION OF ACK9-H3 WAS OBSERVED IN THE NUCLEI OF NEUTROPHILS AND MACROPHAGES SURROUNDING THE EPINEURIUM. ADMINISTRATION OF THE HISTONE ACETYLTRANSFERASE INHIBITOR ANACARDIC ACID SUPPRESSED THE UP-REGULATION OF MIP-2 AND CXCR2 IN THE SCN AFTER PSL AND RESULTED IN THE PREVENTION OF PSL-INDUCED NEUROPATHIC PAIN. TAKEN TOGETHER, THESE RESULTS SHOW THAT AUGMENTATION OF THE MIP-2/CXCR2 AXIS BY HYPERACETYLATION OF HISTONE H3 ON THE PROMOTER REGION OF MIP-2 AND CXCR2 LOCATED IN THE INJURED PERIPHERAL NERVE ELICITS CHRONIC NEUROINFLAMMATION THROUGH NEUTROPHIL ACCUMULATION, LEADING TO NEUROPATHIC PAIN. 2012 2 5692 24 SILENCING OF LNCRNA PKIA-AS1 ATTENUATES SPINAL NERVE LIGATION-INDUCED NEUROPATHIC PAIN THROUGH EPIGENETIC DOWNREGULATION OF CDK6 EXPRESSION. NEUROPATHIC PAIN (NP) IS AMONG THE MOST INTRACTABLE COMORBIDITIES OF SPINAL CORD INJURY. DYSREGULATION OF NON-CODING RNAS HAS ALSO BEEN IMPLICATED IN THE DEVELOPMENT OF NEUROPATHIC PAIN. HERE, WE IDENTIFIED A NOVEL LNCRNA, PKIA-AS1, BY USING LNCRNA ARRAY ANALYSIS IN SPINAL CORD TISSUE OF SPINAL NERVE LIGATION (SNL) MODEL RATS, AND INVESTIGATED THE ROLE OF PKIA-AS1 IN SNL-MEDIATED NEUROPATHIC PAIN. WE OBSERVED THAT PKIA-AS1 WAS SIGNIFICANTLY UPREGULATED IN SNL MODEL RATS AND THAT PKIA-AS1 KNOCKDOWN ATTENUATED NEUROPATHIC PAIN PROGRESSION. ALTERNATIVELY, OVEREXPRESSION OF PKIA-AS1 WAS SUFFICIENT TO INDUCE NEUROPATHIC PAIN-LIKE SYMPTOMS IN UNINJURED RATS. WE ALSO FOUND THAT PKIA-AS1 MEDIATED SNL-INDUCED NEUROPATHIC PAIN BY DIRECTLY REGULATING THE EXPRESSION AND FUNCTION OF CDK6, WHICH IS ESSENTIAL FOR THE INITIATION AND MAINTENANCE OF NEUROINFLAMMATION AND NEUROPATHIC PAIN. THEREFORE, OUR STUDY IDENTIFIES PKIA-AS1 AS A NOVEL THERAPEUTIC TARGET FOR NEUROINFLAMMATION RELATED NEUROPATHIC PAIN. 2019 3 4919 32 PANNEXIN-1 UP-REGULATION IN THE DORSAL ROOT GANGLION CONTRIBUTES TO NEUROPATHIC PAIN DEVELOPMENT. PANNEXIN-1 (PANX1) IS A LARGE-PORE MEMBRANE CHANNEL INVOLVED IN THE RELEASE OF ATP AND OTHER SIGNALING MEDIATORS. LITTLE IS KNOWN ABOUT THE EXPRESSION AND FUNCTIONAL ROLE OF PANX1 IN THE DORSAL ROOT GANGLION (DRG) IN THE DEVELOPMENT OF CHRONIC NEUROPATHIC PAIN. IN THIS STUDY, WE DETERMINED THE EPIGENETIC MECHANISM INVOLVED IN INCREASED PANX1 EXPRESSION IN THE DRG AFTER NERVE INJURY. SPINAL NERVE LIGATION IN RATS SIGNIFICANTLY INCREASED THE MRNA AND PROTEIN LEVELS OF PANX1 IN THE DRG BUT NOT IN THE SPINAL CORD. IMMUNOCYTOCHEMICAL LABELING SHOWED THAT PANX1 WAS PRIMARILY EXPRESSED IN A SUBSET OF MEDIUM AND LARGE DRG NEURONS IN CONTROL RATS AND THAT NERVE INJURY MARKEDLY INCREASED THE NUMBER OF PANX1-IMMUNOREACTIVE DRG NEURONS. NERVE INJURY SIGNIFICANTLY INCREASED THE ENRICHMENT OF TWO ACTIVATING HISTONE MARKS (H3K4ME2 AND H3K9AC) AND DECREASED THE OCCUPANCY OF TWO REPRESSIVE HISTONE MARKS (H3K9ME2 AND H3K27ME3) AROUND THE PROMOTER REGION OF PANX1 IN THE DRG. HOWEVER, NERVE INJURY HAD NO EFFECT ON THE DNA METHYLATION LEVEL AROUND THE PANX1 PROMOTER IN THE DRG. FURTHERMORE, INTRATHECAL INJECTION OF THE PANX1 BLOCKERS OR PANX1-SPECIFIC SIRNA SIGNIFICANTLY REDUCED PAIN HYPERSENSITIVITY INDUCED BY NERVE INJURY. IN ADDITION, SIRNA KNOCKDOWN OF PANX1 EXPRESSION IN A DRG CELL LINE SIGNIFICANTLY REDUCED CASPASE-1 RELEASE INDUCED BY NEURONAL DEPOLARIZATION. OUR FINDINGS SUGGEST THAT NERVE INJURY INCREASES PANX1 EXPRESSION LEVELS IN THE DRG THROUGH ALTERED HISTONE MODIFICATIONS. PANX1 UP-REGULATION CONTRIBUTES TO THE DEVELOPMENT OF NEUROPATHIC PAIN AND STIMULATION OF INFLAMMASOME SIGNALING. 2015 4 1318 32 DEMETHYLATION OF G-PROTEIN-COUPLED RECEPTOR 151 PROMOTER FACILITATES THE BINDING OF KRUPPEL-LIKE FACTOR 5 AND ENHANCES NEUROPATHIC PAIN AFTER NERVE INJURY IN MICE. G-PROTEIN-COUPLED RECEPTORS ARE CONSIDERED TO BE CELL-SURFACE SENSORS OF EXTRACELLULAR SIGNALS, THEREBY HAVING A CRUCIAL ROLE IN SIGNAL TRANSDUCTION AND BEING THE MOST FRUITFUL TARGETS FOR DRUG DISCOVERY. G-PROTEIN-COUPLED RECEPTOR 151 (GPR151) WAS REPORTED TO BE EXPRESSED SPECIFICALLY IN THE HABENULAR AREA. HERE WE REPORT THE EXPRESSION AND THE EPIGENETIC REGULATION OF GRP151 IN THE SPINAL CORD AFTER SPINAL NERVE LIGATION (SNL) AND THE CONTRIBUTION OF GPR151 TO NEUROPATHIC PAIN IN MALE MICE. SNL DRAMATICALLY INCREASED GPR151 EXPRESSION IN SPINAL NEURONS. GPR151 MUTATION OR SPINAL INHIBITION BY SHRNA ALLEVIATED SNL-INDUCED MECHANICAL ALLODYNIA AND HEAT HYPERALGESIA. INTERESTINGLY, THE CPG ISLAND IN THE GPR151 GENE PROMOTER REGION WAS DEMETHYLATED, THE EXPRESSION OF DNA METHYLTRANSFERASE 3B (DNMT3B) WAS DECREASED, AND THE BINDING OF DNMT3B WITH GPR151 PROMOTER WAS REDUCED AFTER SNL. OVEREXPRESSION OF DNMT3B IN THE SPINAL CORD DECREASED GPR151 EXPRESSION AND ATTENUATED SNL-INDUCED NEUROPATHIC PAIN. FURTHERMORE, KRUPPEL-LIKE FACTOR 5 (KLF5), A TRANSCRIPTIONAL FACTOR OF THE KLF FAMILY, WAS UPREGULATED IN SPINAL NEURONS, AND THE BINDING AFFINITY OF KLF5 WITH GPR151 PROMOTER WAS INCREASED AFTER SNL. INHIBITION OF KLF5 REDUCED GPR151 EXPRESSION AND ATTENUATED SNL-INDUCED PAIN HYPERSENSITIVITY. FURTHER MRNA MICROARRAY ANALYSIS REVEALED THAT MUTATION OF GPR151 REDUCED THE EXPRESSION OF A VARIETY OF PAIN-RELATED GENES IN RESPONSE TO SNL, ESPECIALLY MITOGEN-ACTIVATED PROTEIN KINASE (MAPK) SIGNALING PATHWAY-ASSOCIATED GENES. THIS STUDY REVEALS THAT GPR151, INCREASED BY DNA DEMETHYLATION AND THE ENHANCED INTERACTION WITH KLF5, CONTRIBUTES TO THE MAINTENANCE OF NEUROPATHIC PAIN VIA INCREASING MAPK PATHWAY-RELATED GENE EXPRESSION.SIGNIFICANCE STATEMENT G-PROTEIN-COUPLED RECEPTORS (GPCRS) ARE TARGETS OF VARIOUS CLINICALLY APPROVED DRUGS. HERE WE REPORT THAT SNL INCREASED GPR151 EXPRESSION IN THE SPINAL CORD, AND MUTATION OR INHIBITION OF GPR151 ALLEVIATED SNL-INDUCED NEUROPATHIC PAIN. IN ADDITION, SNL DOWNREGULATED THE EXPRESSION OF DNMT3B, WHICH CAUSED DEMETHYLATION OF GPR151 GENE PROMOTER, FACILITATED THE BINDING OF TRANSCRIPTIONAL FACTOR KLF5 WITH THE GPR151 PROMOTER, AND FURTHER INCREASED GPR151 EXPRESSION IN SPINAL NEURONS. THE INCREASED GPR151 MAY CONTRIBUTE TO THE PATHOGENESIS OF NEUROPATHIC PAIN VIA ACTIVATING MAPK SIGNALING AND INCREASING PAIN-RELATED GENE EXPRESSION. OUR STUDY REVEALS AN EPIGENETIC MECHANISM UNDERLYING GPR151 EXPRESSION AND SUGGESTS THAT TARGETING GPR151 MAY OFFER A NEW STRATEGY FOR THE TREATMENT OF NEUROPATHIC PAIN. 2018 5 532 26 ASTROCYTIC C-JUN N-TERMINAL KINASE-HISTONE DEACETYLASE-2 CASCADE CONTRIBUTES TO GLUTAMATE TRANSPORTER-1 DECREASE AND MECHANICAL ALLODYNIA FOLLOWING PERIPHERAL NERVE INJURY IN RATS. DECREASE OF GLUTAMATE TRANSPORTER-1 (GLT-1) IN THE SPINAL DORSAL HORN AFTER NERVE INJURY INDUCES ENHANCED EXCITATORY TRANSMISSION AND CAUSES PERSISTENT PAIN. HISTONE DEACETYLASES (HDACS)-CATALYZED DEACETYLATION MIGHT CONTRIBUTE TO THE DECREASE OF GLT-1, WHILE THE DETAILED MECHANISMS HAVE YET TO BE FULLY ELABORATED. SPINAL NERVE LIGATION (SNL) INDUCED SIGNIFICANT INCREASES OF HDAC2 AND DECREASES OF GLT-1 IN SPINAL ASTROCYTES. INTRATHECAL INFUSION OF THE HDAC2 INHIBITORS ATTENUATED THE DECREASE OF GLT-1 AND ENHANCED PHOSPHORYLATION OF GLUTAMATE RECEPTORS. GLT-1 AND PHOSPHORYLATED C-JUN N-TERMINAL KINASE (JNK) WERE HIGHLY COLOCALIZED IN THE SPINAL CORD, AND A LARGE NUMBER OF PJNK POSITIVE CELLS WERE HDAC2 POSITIVE. INTRATHECALLY INFUSION OF THE JNK INHIBITOR SP600125 SIGNIFICANTLY INHIBITED SNL-INDUCED UPREGULATION OF HDAC2. SNL-INDUCED HDAC2 UP-REGULATION COULD BE INHIBITED BY THE NEUTRALIZING ANTI-TUMOR NECROSIS FACTOR-ALPHA (TNF-ALPHA) BINDING PROTEIN ETANERCEPT OR THE MICROGLIAL INHIBITOR MINOCYCLINE. IN CULTURED ASTROCYTES, TNF-ALPHA INDUCED ENHANCED PHOSPHORYLATION OF JNK AND A SIGNIFICANT INCREASE OF HDAC2, AS WELL AS A REMARKABLE DECREASE OF GLT-1, WHICH COULD BE PREVENTED BY SP600125 OR THE HDAC2 SPECIFIC INHIBITOR CAY10683. OUR DATA SUGGEST THAT ASTROCYTIC JNK-HDAC2 CASCADE CONTRIBUTES TO GLT-1 DECREASE AND MECHANICAL ALLODYNIA FOLLOWING PERIPHERAL NERVE INJURY. NEUROIMMUNE ACTIVATION AFTER PERIPHERAL NERVE INJURY COULD INDUCE EPIGENETIC MODIFICATION CHANGES IN ASTROCYTES AND CONTRIBUTE TO CHRONIC PAIN MAINTENANCE. 2021 6 3368 30 HISTONE METHYLTRANSFERASE G9A DIMINISHES EXPRESSION OF CANNABINOID CB(1) RECEPTORS IN PRIMARY SENSORY NEURONS IN NEUROPATHIC PAIN. TYPE 1 CANNABINOID RECEPTORS (CB(1)RS) ARE EXPRESSED IN THE DORSAL ROOT GANGLION (DRG) AND CONTRIBUTE TO THE ANALGESIC EFFECT OF CANNABINOIDS. HOWEVER, THE EPIGENETIC MECHANISM REGULATING THE EXPRESSION OF CB(1)RS IN NEUROPATHIC PAIN IS UNKNOWN. G9A (ENCODED BY THE EHMT2 GENE), A HISTONE 3 AT LYSINE 9 METHYLTRANSFERASE, IS A KEY CHROMATIN REGULATOR RESPONSIBLE FOR GENE SILENCING. IN THIS STUDY, WE DETERMINED G9A'S ROLE IN REGULATING CB(1)R EXPRESSION IN THE DRG AND IN CB(1)R-MEDIATED ANALGESIC EFFECTS IN AN ANIMAL MODEL OF NEUROPATHIC PAIN. WE SHOW THAT NERVE INJURY PROFOUNDLY REDUCED MRNA LEVELS OF CB(1)RS BUT INCREASED THE EXPRESSION OF CB(2) RECEPTORS IN THE RAT DRG. CHIP RESULTS INDICATED INCREASED ENRICHMENT OF HISTONE 3 AT LYSINE 9 DIMETHYLATION, A G9A-CATALYZED REPRESSIVE HISTONE MARK, AT THE PROMOTER REGIONS OF THE CB(1)R GENES. G9A INHIBITION IN NERVE-INJURED RATS NOT ONLY UP-REGULATED THE CB(1)R EXPRESSION LEVEL IN THE DRG BUT ALSO POTENTIATED THE ANALGESIC EFFECT OF A CB(1)R AGONIST ON NERVE INJURY-INDUCED PAIN HYPERSENSITIVITY. FURTHERMORE, IN MICE LACKING EHMT2 IN DRG NEURONS, NERVE INJURY FAILED TO REDUCE CB(1)R EXPRESSION IN THE DRG AND TO DECREASE THE ANALGESIC EFFECT OF THE CB(1)R AGONIST. MOREOVER, NERVE INJURY DIMINISHED THE INHIBITORY EFFECT OF THE CB(1)R AGONIST ON SYNAPTIC GLUTAMATE RELEASE FROM PRIMARY AFFERENT NERVES TO SPINAL CORD DORSAL HORN NEURONS IN WT MICE BUT NOT IN MICE LACKING EHMT2 IN DRG NEURONS. OUR FINDINGS REVEAL THAT NERVE INJURY DIMINISHES THE ANALGESIC EFFECT OF CB(1)R AGONISTS THROUGH G9A-MEDIATED CB(1)R DOWN-REGULATION IN PRIMARY SENSORY NEURONS. 2020 7 2470 43 EPIGENETIC TRANSCRIPTIONAL ACTIVATION OF MONOCYTE CHEMOTACTIC PROTEIN 3 CONTRIBUTES TO LONG-LASTING NEUROPATHIC PAIN. A MULTIPLEX ANALYSIS FOR PROFILING THE EXPRESSION OF CANDIDATE GENES ALONG WITH EPIGENETIC MODIFICATION MAY LEAD TO A BETTER UNDERSTANDING OF THE COMPLEX MACHINERY OF NEUROPATHIC PAIN. IN THE PRESENT STUDY, WE FOUND THAT PARTIAL SCIATIC NERVE LIGATION MOST REMARKABLY INCREASED THE EXPRESSION OF MONOCYTE CHEMOTACTIC PROTEIN 3 (MCP-3, KNOWN AS CCL7) A TOTAL OF 33 541 GENES IN THE SPINAL CORD, WHICH LASTED FOR 4 WEEKS. THIS INCREASE IN MCP-3 GENE TRANSCRIPTION WAS ACCOMPANIED BY THE DECREASED TRIMETHYLATION OF HISTONE H3 AT LYS27 AT THE MCP-3 PROMOTER. THE INCREASED MCP-3 EXPRESSION ASSOCIATED WITH ITS EPIGENETIC MODIFICATION OBSERVED IN THE SPINAL CORD WAS ALMOST ABOLISHED IN INTERLEUKIN 6 KNOCKOUT MICE WITH PARTIAL SCIATIC NERVE LIGATION. CONSISTENT WITH THESE FINDINGS, A SINGLE INTRATHECAL INJECTION OF RECOMBINANT PROTEINS OF INTERLEUKIN 6 SIGNIFICANTLY INCREASED MCP-3 MESSENGER RNA WITH A DECREASE IN THE LEVEL OF LYS27 TRIMETHYLATION OF HISTONE H3 AT THE MCP-3 PROMOTER IN THE SPINAL CORD OF MICE. FURTHERMORE, DELETION OF THE C-C CHEMOKINE RECEPTOR TYPE 2 (CCR2) GENE, WHICH ENCODES A RECEPTOR FOR MCP-3, FAILED TO AFFECT THE ACCELERATION OF MCP-3 EXPRESSION IN THE SPINAL CORD AFTER PARTIAL SCIATIC NERVE LIGATION. A ROBUST INCREASE IN MCP-3 PROTEIN, WHICH LASTED FOR UP TO 2 WEEKS AFTER SURGERY, IN THE DORSAL HORN OF THE SPINAL CORD OF MICE WITH PARTIAL SCIATIC NERVE LIGATION WAS SEEN MOSTLY IN ASTROCYTES, BUT NOT MICROGLIA OR NEURONS. ON THE OTHER HAND, THE INCREASES IN BOTH MICROGLIA AND ASTROCYTES IN THE SPINAL CORD BY PARTIAL SCIATIC NERVE LIGATION WERE MOSTLY ABOLISHED IN INTERLEUKIN 6 KNOCKOUT MICE. MOREOVER, THIS INCREASE IN MICROGLIA WAS ALMOST ABOLISHED BY CCR2 GENE DELETION, WHEREAS THE INCREASE IN ASTROCYTES WAS NOT AFFECTED IN NERVE-LIGATED MICE THAT LACKED THE CCR2 GENE. WE ALSO FOUND THAT EITHER IN VIVO OR IN VITRO TREATMENT WITH MCP-3 CAUSED ROBUST MICROGLIA ACTIVATION. UNDER THESE CONDITIONS, INTRATHECAL ADMINISTRATION OF MCP-3 ANTIBODY SUPPRESSED THE INCREASE IN MICROGLIA WITHIN THE MOUSE SPINAL CORD AND NEUROPATHIC PAIN-LIKE BEHAVIOURS AFTER NERVE INJURY. WITH THE USE OF A FUNCTIONAL MAGNETIC RESONANCE IMAGING ANALYSIS, WE DEMONSTRATED THAT A SINGLE INTRATHECAL INJECTION OF MCP-3 INDUCED DRAMATIC INCREASES IN SIGNAL INTENSITY IN PAIN-RELATED BRAIN REGIONS. THESE FINDINGS SUGGEST THAT INCREASED MCP-3 EXPRESSION ASSOCIATED WITH INTERLEUKIN 6 DEPENDENT EPIGENETIC MODIFICATION AT THE MCP-3 PROMOTER AFTER NERVE INJURY, MOSTLY IN SPINAL ASTROCYTES, MAY SERVE TO FACILITATE ASTROCYTE-MICROGLIA INTERACTION IN THE SPINAL CORD AND COULD PLAY A CRITICAL ROLE IN THE NEUROPATHIC PAIN-LIKE STATE. 2013 8 6664 22 UPREGULATION OF LNCRNA71132 IN THE SPINAL CORD REGULATES HYPERSENSITIVITY IN A RAT MODEL OF BONE CANCER PAIN. BONE CANCER PAIN (BCP) IS A PERVASIVE CLINICAL SYMPTOM WHICH IMPAIRS THE QUALITY LIFE. LONG NONCODING RNAS (LNCRNAS) ARE ENRICHED IN THE CENTRAL NERVOUS SYSTEM AND PLAY INDISPENSABLE ROLES IN NUMEROUS BIOLOGICAL PROCESSES, WHILE ITS REGULATORY FUNCTION IN NOCICEPTIVE INFORMATION PROCESSING REMAINS ELUSIVE. HERE, WE REPORTED THAT FUNCTIONAL MODULATORY ROLE OF ENSRNOT00000071132 (LNCRNA71132) IN THE BCP PROCESS AND SPONGING WITH MIR-143 AND ITS DOWNSTREAM GPR85-DEPENDENT SIGNALING CASCADE. SPINAL LNCRNA71132 WAS REMARKABLY INCREASED IN THE RAT MODEL OF BONE CANCER PAIN. THE KNOCKDOWN OF SPINAL LNCRNA71132 REVERTED BCP BEHAVIORS AND SPINAL C-FOS NEURONAL SENSITIZATION. OVEREXPRESSION OF SPINAL LNCRNA71132 IN NAIVE RAT GENERATED PAIN BEHAVIORS, WHICH WERE ACCOMPANIED BY INCREASED SPINAL C-FOS NEURONAL SENSITIZATION. FURTHERMORE, IT WAS FOUND THAT LNCRNA71132 PARTICIPATES IN THE MODULATION OF BCP BY INVERSELY REGULATING THE PROCESSING OF MIR-143-5P. IN ADDITION, AN INCREASE IN EXPRESSION OF SPINAL LNCRNA71132 RESULTED IN THE DECREASE IN EXPRESSION OF MIR-143 UNDER THE BCP STATE. FINALLY, IT WAS FOUND THAT MIR-143-5P REGULATES PAIN BEHAVIORS BY TARGETING GPR85. OVEREXPRESSION OF MIR-143-5P IN THE SPINAL CORD REVERTED THE NOCICEPTIVE BEHAVIORS TRIGGERED BY BCP, ACCOMPANIED BY A DECREASE IN EXPRESSION OF SPINAL GPR85 PROTEIN, BUT NO INFLUENCE ON EXPRESSION OF GPR85 MRNA. THE FINDINGS OF THIS STUDY INDICATE THAT LNCRNA71132 WORKS AS A MIRNA SPONGE IN MIR-143-5P-MEDIATED POSTTRANSCRIPTIONAL MODULATION OF GPR85 EXPRESSION IN BCP. THEREFORE, EPIGENETIC INTERVENTIONS AGAINST LNCRNA71132 MAY POTENTIALLY WORK AS NOVEL TREATMENT AVENUES IN TREATING NOCICEPTIVE HYPERSENSITIVITY TRIGGERED BY BONE CANCER. 2023 9 1689 40 DUAL HDAC/BRD4 INHIBITORS RELIEVES NEUROPATHIC PAIN BY ATTENUATING INFLAMMATORY RESPONSE IN MICROGLIA AFTER SPARED NERVE INJURY. DESPITE THE EFFORT ON DEVELOPING NEW TREATMENTS, THERAPY FOR NEUROPATHIC PAIN IS STILL A CLINICAL CHALLENGE AND COMBINATION THERAPY REGIMES OF TWO OR MORE DRUGS ARE OFTEN NEEDED TO IMPROVE EFFICACY. ACCUMULATING EVIDENCE SHOWS AN ALTERED EXPRESSION AND ACTIVITY OF HISTONE ACETYLATION ENZYMES IN CHRONIC PAIN CONDITIONS AND RESTORATION OF THESE ABERRANT EPIGENETIC MODIFICATIONS PROMOTES PAIN-RELIEVING ACTIVITY. RECENT STUDIES SHOWED A SYNERGISTIC ACTIVITY IN NEUROPATHIC PAIN MODELS BY COMBINATION OF HISTONE DEACETYLASES (HDACS) AND BROMODOMAIN AND EXTRA-TERMINAL DOMAIN (BET) INHIBITORS. ON THESE PREMISES, THE PRESENT STUDY INVESTIGATED THE PHARMACOLOGICAL PROFILE OF NEW DUAL HDAC/BRD4 INHIBITORS, NAMED SUM52 AND SUM35, IN THE SPARED NERVE INJURY (SNI) MODEL IN MICE AS INNOVATIVE STRATEGY TO SIMULTANEOUSLY INHIBIT HDACS AND BETS. INTRANASAL ADMINISTRATION OF SUM52 AND SUM35 ATTENUATED THERMAL AND MECHANICAL HYPERSENSITIVITY IN THE ABSENCE OF LOCOMOTOR SIDE EFFECTS. BOTH DUAL INHIBITORS SHOWED A PREFERENTIAL INTERACTION WITH BRD4-BD2 DOMAIN, AND SUM52 RESULTED THE MOST ACTIVE COMPOUND. SUM52 REDUCED MICROGLIA-MEDIATED SPINAL NEUROINFLAMMATION IN SPINAL CORD SECTIONS OF SNI MICE AS SHOWED BY REDUCTION OF IBA1 IMMUNOSTAINING, INDUCIBLE NITRIC OXIDE SYNTHASE (INOS) EXPRESSION, P65 NUCLEAR FACTOR-KAPPAB (NF-KAPPAB) AND P38 MAPK OVER-PHOSPHORYLATION. A ROBUST DECREASE OF THE SPINAL PROINFLAMMATORY CYTOKINES CONTENT (IL-6, IL-1SS) WAS ALSO OBSERVED AFTER SUM52 TREATMENT. PRESENT RESULTS, SHOWING THE PAIN-RELIEVING ACTIVITY OF HDAC/BRD4 DUAL INHIBITORS, INDICATE THAT THE SIMULTANEOUS MODULATION OF BET AND HDAC ACTIVITY BY A SINGLE MOLECULE ACTING AS MULTI-TARGET AGENT MIGHT REPRESENT A PROMISE FOR NEUROPATHIC PAIN RELIEF. 2022 10 2450 36 EPIGENETIC SUPPRESSION OF LIVER X RECEPTOR BETA IN ANTERIOR CINGULATE CORTEX BY HDAC5 DRIVES CFA-INDUCED CHRONIC INFLAMMATORY PAIN. BACKGROUND: LIVER X RECEPTORS (LXRS), INCLUDING LXRALPHA AND LXRBETA, ARE KEY REGULATORS OF TRANSCRIPTIONAL PROGRAMS FOR BOTH CHOLESTEROL HOMEOSTASIS AND INFLAMMATION IN THE BRAIN. HERE, THE MODES OF ACTION OF LXRS AND THE EPIGENETIC MECHANISMS REGULATING LXRBETA EXPRESSION IN ANTERIOR CINGULATE CORTEX (ACC) OF CHRONIC INFLAMMATORY PAIN (CIP) ARE INVESTIGATED. METHODS: THE DEFICIT OF LXR ISOFORM AND ANALGESIC EFFECT OF LXR ACTIVATION BY GW3965 WERE EVALUATED USING THE MOUSE MODEL OF CIP INDUCED BY HINDPAW INJECTION OF COMPLETE FREUND'S ADJUVANT (CFA). THE MECHANISMS INVOLVED IN GW-MEDIATED ANALGESIC EFFECTS WERE ANALYZED WITH IMMUNOHISTOCHEMICAL METHODS, ELISA, CO-IMMUNOPRECIPITATION (CO-IP), WESTERN BLOT, AND ELECTROPHYSIOLOGICAL RECORDING. THE EPIGENETIC REGULATION OF LXRBETA EXPRESSION WAS INVESTIGATED BY CHROMATIN IMMUNOPRECIPITATION, QUANTITATIVE REAL-TIME PCR, AND SEQUENCING. RESULTS: WE REVEALED THAT CFA INSULT LED TO LXRBETA REDUCTION IN ACC, WHICH WAS ASSOCIATED WITH UPREGULATED EXPRESSION OF HISTONE DEACETYLASE 5 (HDAC5), AND KNOCKDOWN OF LXRBETA BY SHRNA LED TO THERMAL HYPERALGESIA. CO-IP SHOWED THAT LXRBETA INTERACTED WITH NF-KAPPAB P65 PHYSICALLY. LXRBETA ACTIVATION BY GW3965 EXERTED ANALGESIC EFFECTS BY INHIBITING THE NUCLEAR TRANSLOCATION OF NF-KAPPAB, REDUCING THE PHOSPHORYLATION OF MITOGEN-ACTIVATED PROTEIN KINASES (MAPKS) IN ACC, AND DECREASING THE PROMOTED INPUT-OUTPUT AND ENHANCED MEPSC FREQUENCY IN ACC NEURONS AFTER CFA EXPOSURE. IN VITRO EXPERIMENTS CONFIRMED THAT HDAC5 TRIGGERED HISTONE DEACETYLATION ON THE PROMOTER REGION OF LXRBETA, RESULTING IN DOWNREGULATION OF LXRBETA TRANSCRIPTION. CONCLUSION: THESE FINDINGS HIGHLIGHT AN EPIGENETIC MECHANISM UNDERLYING LXRBETA DEFICITS LINKED TO CIP, AND LXRBETA ACTIVATION MAY REPRESENT A POTENTIAL NOVEL TARGET FOR THE TREATMENT OF CIP WITH AN ALTERATION IN INFLAMMATION RESPONSES AND SYNAPTIC TRANSMISSION IN ACC. 2019 11 5401 34 REDUCTION OF SIRT1 EPIGENETICALLY UPREGULATES NALP1 EXPRESSION AND CONTRIBUTES TO NEUROPATHIC PAIN INDUCED BY CHEMOTHERAPEUTIC DRUG BORTEZOMIB. BACKGROUND: BORTEZOMIB IS A FREQUENTLY USED CHEMOTHERAPEUTIC DRUG FOR THE TREATMENT OF MULTIPLE MYELOMA AND OTHER NONSOLID MALIGNANCIES. ACCUMULATING EVIDENCE HAS DEMONSTRATED THAT BORTEZOMIB-INDUCED PERSISTENT PAIN SERVES AS THE MOST FREQUENT REASON FOR TREATMENT DISCONTINUATION. METHODS: THE VON FREY TEST WAS PERFORMED TO EVALUATE NEUROPATHIC PAIN BEHAVIOR, AND REAL-TIME QUANTITATIVE REVERSE TRANSCRIPTION POLYMERASE CHAIN REACTION, CHROMATIN IMMUNOPRECIPITATION, WESTERN BLOT, IMMUNOHISTOCHEMISTRY, AND SMALL INTERFERING RNA WERE PERFORMED TO EXPLORE THE MOLECULAR MECHANISMS IN ADULT MALE SPRAGUE-DAWLEY RATS. RESULTS: WE FOUND THAT APPLICATION OF BORTEZOMIB SIGNIFICANTLY INCREASED THE EXPRESSION OF NALP1 PROTEIN AND MRNA LEVELS IN SPINAL DORSAL HORN NEURONS, AND INTRATHECAL APPLICATION OF NALP1 SIRNA ATTENUATED THE BORTEZOMIB-INDUCED MECHANICAL ALLODYNIA. IN ADDITION, BORTEZOMIB ALSO DECREASED THE SIRT1 EXPRESSION, AND TREATMENT WITH SIRT1 ACTIVATOR RESVERATROL AMELIORATED THE NALP1 UPREGULATION AND MECHANICAL ALLODYNIA INDUCED BY BORTEZOMIB. MEANWHILE, KNOCKDOWN OF SIRT1 USING THE SIRT1 SIRNA INDUCED THE NALP1 UPREGULATION IN DORSAL HORN AND MECHANICAL ALLODYNIA IN NORMAL ANIMAL. THESE RESULTS SUGGESTED THAT REDUCTION OF SIRT1 INDUCED THE NALP1 UPREGULATION IN DORSAL HORN NEURONS, AND PARTICIPATED IN BORTEZOMIB-INDUCED MECHANICAL ALLODYNIA. IMPORTANTLY, WE FOUND THAT THE BINDING OF SIRT1 AND NALP1 PROMOTER REGION DID NOT CHANGE BEFORE AND AFTER BORTEZOMIB TREATMENT, BUT SIRT1 DOWNREGULATION INCREASED P-STAT3 EXPRESSION. FURTHERMORE, THE ACTIVATION OF STAT3 ENHANCED THE RECRUITMENT OF P-STAT3 TO THE NALP1 GENE PROMOTER, WHICH INCREASED THE ACETYLATION OF HISTONE H3 AND H4 IN NALP1 PROMOTER REGIONS AND EPIGENETICALLY UPREGULATED NALP1 EXPRESSION IN THE RODENTS WITH BORTEZOMIB TREATMENT. CONCLUSION: THESE FINDINGS SUGGESTED A NEW EPIGENETIC MECHANISM FOR NALP1 UPREGULATION INVOLVING SIRT1 REDUCTION AND SUBSEQUENT STAT3-MEDIATED HISTONE HYPERACETYLATION IN NALP1 PROMOTER REGION IN DORSAL HORN NEURONS, WHICH CONTRIBUTED TO THE BORTEZOMIB-INDUCED MECHANICAL ALLODYNIA. 2018 12 6148 26 THE EXPRESSION OF TRANSCRIPTION FACTORS MECP2 AND CREB IS MODULATED IN INFLAMMATORY PELVIC PAIN. EARLY ACTIVATION OF TRANSCRIPTION FACTORS IS ONE OF THE EPIGENETIC MECHANISMS CONTRIBUTING TO THE INDUCTION AND MAINTENANCE OF CHRONIC PAIN STATES. PREVIOUS STUDIES IDENTIFIED THE CHANGES IN A NUMBER OF NOCICEPTION-RELATED GENES, SUCH AS CALCITONIN GENE-RELATED PEPTIDE (CGRP), SUBSTANCE P (SP), AND BRAIN-DERIVED NEUROTROPIC FACTOR (BDNF) IN THE PELVIC ORGANS AFTER TRANSIENT COLONIC INFLAMMATION. THE GENE AND PROTEIN EXPRESSION OF THESE NEUROPEPTIDES COULD BE MODULATED BY TRANSCRIPTION FACTORS METHYL-CPG-BINDING PROTEIN 2 (MECP2) AND CAMP RESPONSE ELEMENT-BINDING PROTEIN (CREB). IN THIS STUDY, WE AIMED TO EVALUATE TIME-DEPENDENT CHANGES IN THE EXPRESSION LEVELS OF MECP2 AND CREB IN THE LUMBOSACRAL (LS) SPINAL CORD AND SENSORY GANGLIA AFTER INFLAMMATION-INDUCED PELVIC PAIN IN RAT. ADULT SPRAGUE-DAWLEY RATS WERE TREATED WITH 2,4,6-TRINITROBENZENESULFONIC ACID (TNBS) TO INDUCE TRANSIENT COLONIC INFLAMMATION. LS (L6-S2) SPINAL CORD SEGMENTS AND RESPECTIVE DORSAL ROOT GANGLIAS (DRGS) WERE ISOLATED FROM CONTROL AND EXPERIMENTAL ANIMALS AT 1, 2, 6, 24 H AND 3 DAYS POST-TNBS TREATMENT. IMMUNOHISTOCHEMICAL (IHC) LABELING AND WESTERN BLOTTING EXPERIMENTS WERE PERFORMED TO ASSESS THE EXPRESSION OF MECP2, CREB AND THEIR PHOSPHORYLATED FORMS. TOTAL MECP2 EXPRESSION, BUT NOT PHOSPHORYLATED P-MECP2 (PS421MECP2) EXPRESSION WAS DETECTED IN THE CELLS OF THE SPINAL DORSAL HORN UNDER CONTROL CONDITIONS. COLONIC INFLAMMATION TRIGGERED A SIGNIFICANT DECREASE IN THE NUMBER OF MECP2-EXPRESSING NEURONS IN PARALLEL WITH ELEVATED NUMBERS OF PS421MECP2-EXPRESSING CELLS AT 2 H AND 6 H POST-TNBS. THE MAJORITY OF MECP2-POSITIVE CELLS (80 +/- 6%) CO-EXPRESSED CREB. TNBS TREATMENT CAUSED A TRANSIENT UP-REGULATION OF CREB-EXPRESSING CELLS AT 1 H POST-TNBS ONLY. THE NUMBER OF CELLS EXPRESSING PHOSPHORYLATED CREB (PS133CREB) DID NOT CHANGE AT 1 H AND 2 H POST-TNBS, BUT WAS DOWN-REGULATED BY THREE FOLDS AT 6 H POST-TNBS. ANALYSIS OF DRG SECTIONS REVEALED THAT THE NUMBER OF MECP2-POSITIVE NEURONS WAS UP-REGULATED BY TNBS TREATMENT, REACHING THREE-FOLD INCREASE AT 2 H POST-TNBS, AND EIGHT-FOLD INCREASE AT 6 H POST-TNBS (P