1 4698 100 NFATC2-DEPENDENT EPIGENETIC DOWNREGULATION OF THE TSC2/BECLIN-1 PATHWAY IS INVOLVED IN NEUROPATHIC PAIN INDUCED BY OXALIPLATIN. NEUROPATHIC PAIN IS A COMMON DOSE-LIMITING SIDE EFFECT OF OXALIPLATIN, WHICH HAMPERS THE EFFECTIVE TREATMENT OF TUMORS. HERE, WE FOUND THAT UPREGULATION OF TRANSCRIPTION FACTOR NFATC2 DECREASED THE EXPRESSION OF BECLIN-1, A CRITICAL MOLECULE IN AUTOPHAGY, IN THE SPINAL DORSAL HORN, AND CONTRIBUTED TO NEUROPATHIC PAIN FOLLOWING OXALIPLATIN TREATMENT. MEANWHILE, MANIPULATING AUTOPHAGY LEVELS BY INTRATHECAL INJECTION OF RAPAMYCIN (RAPA) OR 3-METHYLADENINE (3-MA) DIFFERENTIALLY ALTERED MECHANICAL ALLODYNIA IN OXALIPLATIN-TREATED OR NAIVE RATS. UTILIZING CHROMATIN IMMUNOPRECIPITATION-SEQUENCING (CHIP-SEQ) ASSAY COMBINED WITH BIOINFORMATICS ANALYSIS, WE FOUND THAT NFATC2 NEGATIVELY REGULATED THE TRANSCRIPTION OF TUBEROUS SCLEROSIS COMPLEX PROTEIN 2 (TSC2), WHICH CONTRIBUTED TO THE OXALIPLATIN-INDUCED BECLIN-1 DOWNREGULATION. FURTHER ASSAYS REVEALED THAT NFATC2 REGULATED HISTONE H4 ACETYLATION AND METHYLATION IN THE TSC2 PROMOTER SITE 1 IN RATS' DORSAL HORNS WITH OXALIPLATIN TREATMENT. THESE RESULTS SUGGESTED THAT NFATC2 MEDIATED THE EPIGENETIC DOWNREGULATION OF THE TSC2/BECLIN-1 AUTOPHAGY PATHWAY AND CONTRIBUTED TO OXALIPLATIN-INDUCED MECHANICAL ALLODYNIA, WHICH PROVIDED A NEW THERAPEUTIC INSIGHT FOR CHEMOTHERAPY-INDUCED NEUROPATHIC PAIN. 2023 2 2565 32 EPIGENETICS INVOLVEMENT IN OXALIPLATIN-INDUCED POTASSIUM CHANNEL TRANSCRIPTIONAL DOWNREGULATION AND HYPERSENSITIVITY. PERIPHERAL NEUROPATHY IS THE MOST FREQUENT DOSE-LIMITING ADVERSE EFFECT OF OXALIPLATIN. ACUTE PAIN SYMPTOMS THAT ARE INDUCED OR EXACERBATED BY COLD OCCUR IN ALMOST ALL PATIENTS IMMEDIATELY FOLLOWING THE FIRST INFUSIONS. EVIDENCE HAS SHOWN THAT OXALIPLATIN CAUSES ION CHANNEL EXPRESSION MODULATIONS IN DORSAL ROOT GANGLIA NEURONS, WHICH ARE THOUGHT TO CONTRIBUTE TO PERIPHERAL HYPERSENSITIVITY. MOST DYSREGULATED GENES ENCODE ION CHANNELS INVOLVED IN COLD AND MECHANICAL PERCEPTION, NOTEWORTHY MEMBERS OF A SUB-GROUP OF POTASSIUM CHANNELS OF THE K2P FAMILY, TREK AND TRAAK. DOWNREGULATION OF THESE K2P CHANNELS HAS BEEN IDENTIFIED AS AN IMPORTANT TUNER OF ACUTE OXALIPLATIN-INDUCED HYPERSENSITIVITY. WE INVESTIGATED THE MOLECULAR MECHANISMS UNDERLYING THIS PERIPHERAL DYSREGULATION IN A MURINE MODEL OF NEUROPATHIC PAIN TRIGGERED BY A SINGLE OXALIPLATIN ADMINISTRATION. WE FOUND THAT OXALIPLATIN-MEDIATED TREK-TRAAK DOWNREGULATION, AS WELL AS DOWNREGULATION OF OTHER K(+) CHANNELS OF THE K2P AND KV FAMILIES, INVOLVES A TRANSCRIPTION FACTOR KNOWN AS THE NEURON-RESTRICTIVE SILENCER FACTOR (NRSF) AND ITS EPIGENETIC CO-REPRESSORS HISTONE DEACETYLASES (HDACS). NRSF KNOCKDOWN WAS ABLE TO PREVENT MOST OF THESE K(+) CHANNEL MRNA DOWNREGULATION IN MICE DORSAL ROOT GANGLION NEURONS AS WELL AS OXALIPLATIN-INDUCED ACUTE COLD AND MECHANICAL HYPERSENSITIVITY. INTERESTINGLY, PHARMACOLOGICAL INHIBITION OF CLASS I HDAC REPRODUCES THE ANTINOCICEPTIVE EFFECTS OF NRSF KNOCKDOWN AND LEADS TO AN INCREASED K(+) CHANNEL EXPRESSION IN OXALIPLATIN-TREATED MICE. 2021 3 4699 55 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 4 5402 46 REDUCTION OF SIRT1-MEDIATED EPIGENETIC UPREGULATION OF NAV1.7 CONTRIBUTES TO OXALIPLATIN-INDUCED NEUROPATHIC PAIN. BACKGROUND: CLINICALLY, NEUROPATHIC PAIN IS A SEVERE SIDE EFFECT OF OXALIPLATIN CHEMOTHERAPY, WHICH USUALLY LEADS TO DOSE REDUCTION OR CESSATION OF TREATMENT. DUE TO THE UNAWARENESS OF DETAILED MECHANISMS OF OXALIPLATIN-INDUCED NEUROPATHIC PAIN, IT IS DIFFICULT TO DEVELOP AN EFFECTIVE THERAPY AND LIMITS ITS CLINICAL USE. OBJECTIVES: THE AIM OF THE PRESENT STUDY WAS TO IDENTIFY THE ROLE OF SIRTUIN 1 (SIRT1) REDUCTION IN EPIGENETIC REGULATION OF THE EXPRESSION OF VOLTAGE-GATED SODIUM CHANNELS 1.7 (NAV1.7) IN THE DORSAL ROOT GANGLION (DRG) DURING OXALIPLATIN-INDUCED NEUROPATHIC PAIN. STUDY DESIGN: CONTROLLED ANIMAL STUDY. SETTING: UNIVERSITY LABORATORY. METHODS: THE VON FREY TEST WAS PERFORMED TO EVALUATE PAIN BEHAVIOR IN RATS. REAL-TIME QUANTITATIVE POLYMERASE CHAIN REACTION, WESTERN BLOTTING, ELECTROPHYSIOLOGICAL RECORDING, CHROMATIN IMMUNOPRECIPITATION, AND SMALL INTERFERING RNA (SIRNA) WERE USED TO ILLUSTRATE THE MECHANISMS. RESULTS: IN THE PRESENT STUDY, WE FOUND THAT BOTH THE ACTIVITY AND EXPRESSION OF SIRT1 WERE SIGNIFICANTLY DECREASED IN RAT DRG FOLLOWING OXALIPLATIN TREATMENT. THE ACTIVATOR OF SIRT1, RESVERATROL, NOT ONLY INCREASED THE ACTIVITY AND EXPRESSION OF SIRT1, BUT ALSO ATTENUATED THE MECHANICAL ALLODYNIA FOLLOWING OXALIPLATIN TREATMENT. IN ADDITION, LOCAL KNOCKDOWN OF SIRT1 BY INTRATHECAL INJECTION OF SIRT1 SIRNA CAUSED MECHANICAL ALLODYNIA IN NAIVE RATS. BESIDES, OXALIPLATIN TREATMENT ENHANCED THE ACTION POTENTIAL FIRING FREQUENCY OF DRG NEURONS AND THE EXPRESSION OF NAV1.7 IN DRG AND ACTIVATION OF SIRT1 BY RESVERATROL REVERSED THIS EFFECT. FURTHERMORE, BLOCKING NAV1.7 BY PROTX II (A SELECTIVE NAV1.7 CHANNEL BLOCKER) REVERSED OXALIPLATIN-INDUCED MECHANICAL ALLODYNIA. IN ADDITION, HISTONE H3 HYPERACETYLATION AT THE NAV1.7 PROMOTER IN DRG OF RATS FOLLOWING OXALIPLATIN TREATMENT WAS SIGNIFICANTLY SUPPRESSED BY ACTIVATION OF SIRT1 WITH RESVERATROL. MOREOVER, BOTH THE EXPRESSION OF NAV1.7 AND HISTONE H3 ACETYLATION AT THE NAV1.7 PROMOTER WERE UPREGULATED IN THE DRG BY LOCAL KNOCKDOWN OF SIRT1 WITH SIRT1 SIRNA IN NAIVE RATS. LIMITATIONS: MORE UNDERLYING MECHANISM(S) OF SIRT1 REDUCTION AFTER OXALIPLATIN TREATMENT NEEDS TO BE EXPLORED IN FUTURE RESEARCH. CONCLUSIONS: THESE FINDINGS SUGGEST THAT REDUCTION OF SIRT1-MEDIATED EPIGENETIC UPREGULATION OF NAV1.7 IN THE DRG CONTRIBUTES TO THE DEVELOPMENT OF OXALIPLATIN-INDUCED NEUROPATHIC PAIN IN RATS. THE INTRATHECAL DRUG DELIVERY TREATMENT OF ACTIVATING SIRT1 MIGHT BE A NOVEL THERAPEUTIC OPTION FOR OXALIPLATIN-INDUCED NEUROPATHIC PAIN. 2023 5 2898 44 GATA3-DEPENDENT EPIGENETIC UPREGULATION OF CCL21 IS INVOLVED IN THE DEVELOPMENT OF NEUROPATHIC PAIN INDUCED BY BORTEZOMIB. THE INCIDENCE OF BORTEZOMIB-INDUCED NEUROPATHIC PAIN HAMPERS THE PROGRESS OF THERAPY FOR NEOPLASIA AND ALSO NEGATIVELY AFFECTS THE QUALITY OF LIFE OF PATIENTS. HOWEVER, THE MOLECULAR MECHANISM UNDERLYING BORTEZOMIB-INDUCED NEUROPATHIC PAIN REMAINS UNKNOWN. IN THIS STUDY, WE FOUND THAT THE APPLICATION OF BORTEZOMIB SIGNIFICANTLY INCREASED THE EXPRESSION OF GATA-BINDING PROTEIN 3 (GATA3) IN THE SPINAL DORSAL HORN, AND INTRATHECAL ADMINISTRATION OF GATA3 SIRNA ATTENUATED MECHANICAL ALLODYNIA. FURTHERMORE, CHROMATIN IMMUNOPRECIPITATION SEQUENCING SHOWED THAT BORTEZOMIB TREATMENT INDUCED THE REDISTRIBUTION OF GATA3 TO TRANSCRIPTIONAL RELEVANT REGIONS. NOTABLY, COMBINED WITH THE RESULTS OF MRNA MICROARRAY, WE FOUND THAT C-C MOTIF CHEMOKINE LIGAND 21 (CCL21) HAD AN INCREASED GATA3 BINDING AND UPREGULATED MRNA EXPRESSION IN THE DORSAL HORN AFTER BORTEZOMIB TREATMENT. NEXT, WE FOUND THAT BORTEZOMIB TREATMENT INDUCED CCL21 UPREGULATION IN THE SPINAL NEURONS, WHICH WAS SIGNIFICANTLY REDUCED UPON GATA3 SILENCING. BLOCKADE OF CCL21 USING THE NEUTRALIZING ANTIBODY OR SPECIAL SIRNA AMELIORATED MECHANICAL ALLODYNIA INDUCED BY BORTEZOMIB. IN ADDITION, BORTEZOMIB TREATMENT INCREASED THE ACETYLATION OF HISTONE H3 AND THE INTERACTION BETWEEN GATA3 AND CREB-BINDING PROTEIN. GATA3 SIRNA SUPPRESSED THE CCL21 UPREGULATION BY DECREASING THE ACETYLATION OF HISTONE H3. TOGETHER, THESE RESULTS SUGGESTED THAT ACTIVATION OF GATA3 MEDIATED THE EPIGENETIC UPREGULATION OF CCL21 IN DORSAL HORN NEURONS, WHICH CONTRIBUTED TO THE BORTEZOMIB-INDUCED NEUROPATHIC PAIN. 2019 6 5851 40 SUBEROYLANILIDE HYDROXAMIC ACID TRIGGERS AUTOPHAGY BY INFLUENCING THE MTOR PATHWAY IN THE SPINAL DORSAL HORN IN A RAT NEUROPATHIC PAIN MODEL. HISTONE ACETYLATION LEVELS CAN BE UPREGULATED BY TREATING CELLS WITH HISTONE DEACETYLASE INHIBITORS (HDACIS), WHICH CAN INDUCE AUTOPHAGY. AUTOPHAGY FLUX IN THE SPINAL CORD OF RATS FOLLOWING THE LEFT FIFTH LUMBER SPINAL NERVE LIGATION (SNL) IS INVOLVED IN THE PROGRESSION OF NEUROPATHIC PAIN. SUBEROYLANILIDE HYDROXAMIC ACID (SAHA), ONE OF THE HDACIS CAN INTERFERE WITH THE EPIGENETIC PROCESS OF HISTONE ACETYLATION, WHICH HAS BEEN SHOWN TO EASE NEUROPATHIC PAIN. RECENT RESEARCH SUGGEST THAT SAHA CAN STIMULATE AUTOPHAGY VIA THE MAMMALIAN TARGET OF RAPAMYCIN (MTOR) PATHWAY IN SOME TYPES OF CANCER CELLS. HOWEVER, LITTLE IS KNOWN ABOUT THE ROLE OF SAHA AND AUTOPHAGY IN NEUROPATHIC PAIN AFTER NERVE INJURY. IN THE PRESENT STUDY, WE AIM TO INVESTIGATE AUTOPHAGY FLUX AND THE ROLE OF THE MTOR PATHWAY ON SPINAL CELLS AUTOPHAGY ACTIVATION IN NEUROPATHIC PAIN INDUCED BY SNL IN RATS THAT RECEIVED SAHA TREATMENT. AUTOPHAGY-RELATED PROTEINS AND MTOR OR ITS ACTIVE FORM WERE ASSESSED BY USING WESTERN BLOT, IMMUNOHISTOCHEMISTRY, DOUBLE IMMUNOFLUORESCENCE STAINING AND TRANSMISSION ELECTRON MICROSCOPY (TEM). WE FOUND THAT SAHA DECREASED THE PAW MECHANICAL WITHDRAWAL THRESHOLD (PMWT) OF THE LOWER COMPARED WITH SNL. AUTOPHAGY FLUX WAS MAINLY DISRUPTED IN THE ASTROCYTES AND NEURONAL CELLS OF THE SPINAL CORD DORSAL HORN ON POSTSURGICAL DAY 28 AND WAS REVERSED BY DAILY INTRATHECAL INJECTION OF SAHA (N = 100 NMOL/DAY OR N = 200 NMOL/DAY). SAHA ALSO DECREASED MTOR AND PHOSPHORYLATED MTOR (P-MTOR) EXPRESSION, ESPECIALLY P-MTOR EXPRESSION IN ASTROCYTES AND NEURONAL CELLS OF THE SPINAL DORSAL HORN. THESE RESULTS SUGGEST THAT SAHA ATTENUATES NEUROPATHIC PAIN AND CONTRIBUTES TO AUTOPHAGY FLUX IN ASTROCYTES AND NEURONAL CELLS OF THE SPINAL DORSAL HORN VIA THE MTOR SIGNALING PATHWAY. 2019 7 5401 47 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 8 2785 36 EZH2 REGULATES SPINAL NEUROINFLAMMATION IN RATS WITH NEUROPATHIC PAIN. ALTERATION IN GENE EXPRESSION ALONG THE PAIN SIGNALING PATHWAY IS A KEY MECHANISM CONTRIBUTING TO THE GENESIS OF NEUROPATHIC PAIN. ACCUMULATING STUDIES HAVE SHOWN THAT EPIGENETIC REGULATION PLAYS A CRUCIAL ROLE IN NOCICEPTIVE PROCESS IN THE SPINAL DORSAL HORN. IN THIS PRESENT STUDY, WE INVESTIGATED THE ROLE OF ENHANCER OF ZESTE HOMOLOG-2 (EZH2), A SUBUNIT OF THE POLYCOMB REPRESSIVE COMPLEX 2, IN THE SPINAL DORSAL HORN IN THE GENESIS OF NEUROPATHIC PAIN IN RATS INDUCED BY PARTIAL SCIATIC NERVE LIGATION. EZH2 IS A HISTONE METHYLTRANSFERASE, WHICH CATALYZES THE METHYLATION OF HISTONE H3 ON K27 (H3K27), RESULTING IN GENE SILENCING. WE FOUND THAT LEVELS OF EZH2 AND TRI-METHYLATED H3K27 (H3K27TM) IN THE SPINAL DORSAL HORN WERE INCREASED IN RATS WITH NEUROPATHIC PAIN ON DAY 3 AND DAY 10 POST NERVE INJURIES. EZH2 WAS PREDOMINANTLY EXPRESSED IN NEURONS IN THE SPINAL DORSAL HORN UNDER NORMAL CONDITIONS. THE NUMBER OF NEURONS WITH EZH2 EXPRESSION WAS INCREASED AFTER NERVE INJURY. MORE STRIKINGLY, NERVE INJURY DRASTICALLY INCREASED THE NUMBER OF MICROGLIA WITH EZH2 EXPRESSION BY MORE THAN SEVENFOLD. INTRATHECAL INJECTION OF THE EZH2 INHIBITOR ATTENUATED THE DEVELOPMENT AND MAINTENANCE OF MECHANICAL AND THERMAL HYPERALGESIA IN RATS WITH NERVE INJURY. SUCH ANALGESIC EFFECTS WERE CONCURRENTLY ASSOCIATED WITH THE REDUCED LEVELS OF EZH2, H3K27TM, IBA1, GFAP, TNF-ALPHA, IL-1BETA, AND MCP-1 IN THE SPINAL DORSAL HORN IN RATS WITH NERVE INJURY. OUR RESULTS HIGHLY SUGGEST THAT TARGETING THE EZH2 SIGNALING PATHWAY COULD BE AN EFFECTIVE APPROACH FOR THE MANAGEMENT OF NEUROPATHIC PAIN. 2017 9 2470 36 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 10 743 37 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 11 5781 34 SPINAL SIRT1 ACTIVATION ATTENUATES NEUROPATHIC PAIN IN MICE. ABNORMAL HISTONE ACETYLATION OCCURS DURING NEUROPATHIC PAIN THROUGH AN EPIGENETIC MECHANISM. SILENT INFORMATION REGULATOR 1 (SIR2 OR SIRT1), A NAD-DEPENDENT DEACETYLASE, PLAYS COMPLEX SYSTEMIC ROLES IN A VARIETY OF PROCESSES THROUGH DEACETYLATING ACETYLATED HISTONE AND OTHER SPECIFIC SUBSTRATES. BUT THE ROLE OF SIRT1 IN NEUROPATHIC PAIN IS NOT WELL ESTABLISHED YET. THE PRESENT STUDY WAS INTENDED TO DETECT SIRT1 CONTENT AND ACTIVITY, NICOTINAMIDE (NAM) AND NICOTINAMIDE ADENINE DINUCLEOTIDE (NAD) IN THE SPINAL CORD USING IMMUNOBLOTTING OR MASS SPECTROSCOPY OVER TIME IN MICE FOLLOWING CHRONIC CONSTRICTION INJURY (CCI) OR SHAM SURGERY. IN ADDITION, THE EFFECT OF INTRATHECAL INJECTION OF NAD OR RESVERATROL ON THERMAL HYPERALGESIA AND MECHANICAL ALLODYNIA WAS EVALUATED IN CCI MICE. FINALLY, WE INVESTIGATED WHETHER SIRT1 INHIBITOR EX-527 COULD REVERSE THE ANTI-NOCICEPTIVE EFFECT OF NAD OR RESVERATROL. IT WAS FOUND THAT SPINAL SIRT1 EXPRESSION, DEACETYLASE ACTIVITY AND NAD/NAM DECREASED SIGNIFICANTLY 1, 3, 7, 14 AND 21 DAYS AFTER CCI SURGERY AS COMPARED WITH SHAM GROUP. IN ADDITION, DAILY INTRATHECAL INJECTION OF 5 MICROL 800 MM NAD 1 H BEFORE AND 1 DAY AFTER CCI SURGERY OR SINGLE INTRATHECAL INJECTION OF 5 MICROL 90 MM RESVERATROL 1 H BEFORE CCI SURGERY PRODUCED A TRANSIENT INHIBITORY EFFECT ON THERMAL HYPERALGESIA AND MECHANICAL ALLODYNIA IN CCI MICE. FINALLY, AN INTRATHECAL INJECTION OF 5 MICROL 1.2 MM EX-527 1 H BEFORE NAD OR RESVERATROL ADMINISTRATION REVERSED THE ANTI-NOCICEPTIVE EFFECT OF NAD OR RESVERATROL. THESE DATA INDICATE THAT THE REDUCTION IN SIRT1 DEACETYLASE ACTIVITY MAY BE A FACTOR CONTRIBUTING TO THE DEVELOPMENT OF NEUROPATHIC PAIN IN CCI MICE. OUR FINDINGS SUGGEST THAT THE ENHANCEMENT OF SPINAL NAD/NAM AND/OR SIRT1 ACTIVITY MAY BE A POTENTIALLY PROMISING STRATEGY FOR THE PREVENTION OR TREATMENT OF NEUROPATHIC PAIN. 2014 12 3832 30 INVOLVEMENT OF SPINAL SIRT1 IN DEVELOPMENT OF CHRONIC CONSTRICTION INJURY INDUCED NEUROPATHIC PAIN IN RATS. IT IS KNOWN THAT THE EPIGENETIC PROCESS OF HISTONE ACETYLATION IS INVOLVED IN THE NEUROPATHIC PAIN. THE AIM OF THIS STUDY WAS TO DETERMINE WHETHER SIRTUIN TYPE 1 (SIRT1), AN NAD(+) DEPENDENT DEACETYLASE, AFFECTED ALLODYNIA AND HYPERALGESIA IN NEUROPATHIC PAIN. THE NEUROPATHIC PAIN MODEL WAS ESTABLISHED BY LIGATURE OF THE RIGHT SCIATIC NERVE TO INDUCE CHRONIC CONSTRICTION INJURY (CCI) IN RATS. HISTONE ACETYLTRANSFERASE (HAT) ACTIVITY WAS INCREASED AND, AND HISTONE DEACETYLASE (HDAC) ACTIVITY WAS DECLINED IN TISSUE OF THE SPINAL DORSA HORN IN CCI RATES BY MEANS OF ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA). THE PERSISTENT HYPERALGESIA AND ALLODYNIA CAUSED BY CCI WERE ASSOCIATED WITH DOWNREGULATION OF SIRT1 AND UPREGULATION OF ACETYLATED-H3 (AC-H3) IN TISSUE OF THE SPINAL CORD BY WESTERN BLOT ASSAY, WHICH WAS REVERSED AFTER INTRATHECAL INJECTION OF SIRT1 AGONIST SRT1720. SRT1720 TREATMENT ACHIEVED ANALGESIC THROUGH INHIBITING THE ACETYLATION OF NUCLEAR FACTOR KAPPA B (NF-KAPPAB) AND BLOCKING THE RELEASES OF THE INFLAMMATORY FACTORS INCLUDING TUMOR NECROSIS FACTOR-ALPHA (TNF-ALPHA) AND INTERLEUKIN (IL)-6 BY MEANS OF WESTERN BLOT AND REAL-TIME QUANTITATIVE PCR (RT-PCR), RESPECTIVELY. TAKEN TOGETHER, THESE DATA SUGGEST THAT SIRT1 IN THE SPINAL CORD PLAYS AN IMPORTANT ROLE IN THE NEUROPATHIC PAIN IN THE RAT MODEL. 2018 13 2477 33 EPIGENETIC UPREGULATION OF CDK5 IN THE DORSAL HORN CONTRIBUTES TO NEUROPATHIC PAIN IN RATS. NUMEROUS REPORTS HAVE SHOWN THAT CYCLIN-DEPENDENT KINASE 5 (CDK5), A PROLINE-DIRECTED SERINE/THREONINE KINASE, CRITICALLY CONTRIBUTES TO THE INDUCTION AND MAINTENANCE OF CHRONIC PAIN INDUCED BY PERIPHERAL INFLAMMATION AND NERVE INJURY. RECENT EVIDENCE HAS ALSO SUGGESTED THE CRITICAL ROLE OF AN EPIGENETIC MECHANISM IN THE SETTING OF CHRONIC PAIN. THE PRESENT STUDY AIMS TO ELUCIDATE THE CYCLIC AMP RESPONSE ELEMENT-BINDING PROTEIN (CREB)-MEDIATED UPREGULATION OF CDK5 AND ITS FUNCTIONAL SIGNIFICANCE IN RATS WITH NEUROPATHIC PAIN INDUCED BY CHRONIC CONSTRICTION INJURY (CCI) IN THE SCIATIC NERVE. SIGNIFICANTLY INCREASED EXPRESSION OF CDK5 WAS OBSERVED IN THE DORSAL HORN OF RATS WITH CCI, AND INTRATHECAL DELIVERY OF CDK5 INHIBITOR ROSCOVITINE SIGNIFICANTLY ATTENUATED THE MECHANICAL ALLODYNIA IN THESE RATS. PHOSPHORYLATION OF CREB AND ITS OCCUPANCY IN THE CDK5 PROMOTER REGION WAS ALSO INCREASED IN THE DORSAL HORN, WHICH LED TO INCREASED HISTONE H4 ACETYLATION IN THE CDK5 PROMOTER REGION AND THE UPREGULATED TRANSCRIPTION OF CDK5. INHIBITION OF CREB ACTIVITY ATTENUATED THE UPREGULATION OF CDK5 AND ALLEVIATED THE MECHANICAL ALLODYNIA IN RATS WITH CCI. THESE RESULTS DEMONSTRATED A CREB-MEDIATED EPIGENETIC UPREGULATION OF CDK5 IN THE DORSAL HORN, WHICH CRITICALLY CONTRIBUTED TO THE MAINTENANCE OF PAINFUL BEHAVIOR IN THE RATS WITH NEUROPATHIC PAIN. 2014 14 2479 45 EPIGENETIC UPREGULATION OF CXCL12 EXPRESSION MEDIATES ANTITUBULIN CHEMOTHERAPEUTICS-INDUCED NEUROPATHIC PAIN. CLINICALLY, MICROTUBULE-TARGETED AGENTS-INDUCED NEUROPATHIC PAIN HAMPERS CHEMOTHERAPEUTICS FOR PATIENTS WITH CANCER. HERE, WE FOUND THAT APPLICATION OF PACLITAXEL OR VINCRISTINE INCREASED THE PROTEIN AND MRNA EXPRESSION OF CXCL12 AND FREQUENCY AND AMPLITUDE OF MINIATURE EXCITATORY POST SYNAPTIC CURRENTS (MEPSCS) IN SPINAL DORSAL HORN NEURONS. SPINAL LOCAL APPLICATION OF CXCL12 INDUCED THE LONG-TERM POTENTIATION OF NOCICEPTIVE SYNAPTIC TRANSMISSION AND INCREASED THE AMPLITUDE OF MEPSCS. INHIBITION OF CXCL12 USING THE TRANSGENIC MICE (CXCL12) OR NEUTRALIZING ANTIBODY OR SIRNA AMELIORATED THE MEPSC'S ENHANCEMENT AND MECHANICAL ALLODYNIA. IN ADDITION, PACLITAXEL AND VINCRISTINE BOTH COULD INCREASE THE PHOSPHORYLATION OF SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION 3 (STAT3) AND THE ACETYLATION OF HISTONE H4 IN THE CXCL12-EXPRESSING NEURONS. IMMUNOPRECIPITATION AND CHROMATIN IMMUNOPRECIPITATION ASSAYS DEMONSTRATED THAT ANTITUBULIN CHEMOTHERAPEUTICS INCREASED THE BINDING OF STAT3 TO THE CXCL12 GENE PROMOTER AND THE INTERACTION BETWEEN STAT3 AND P300, AND CONTRIBUTED TO THE ENHANCED TRANSCRIPTION OF CXCL12 BY INCREASING THE ACETYLATION OF HISTONE H4 IN CXCL12 GENE PROMOTER. INHIBITION OF STAT3 BY INTRATHECAL INJECTION OF ADENO-ASSOCIATED VIRUS ENCODING CRE AND GREEN FLUORESCENT PROTEIN INTO STAT3 MICE OR INHIBITOR S3I-201 INTO RATS SUPPRESSED THE CXCL12 UPSURGE BY DECREASING THE ACETYLATION OF HISTONE H4. FINALLY, BLOCKADE OF CXCR4 BUT NOT CXCR7 AMELIORATED THE PACLITAXEL- OR VINCRISTINE-INDUCED MECHANICAL ALLODYNIA. TOGETHER, THESE RESULTS SUGGESTED THAT ENHANCED INTERACTION BETWEEN STAT3 AND P300 MEDIATED THE EPIGENETIC UPREGULATION OF CXCL12 IN DORSAL HORN NEURONS, WHICH CONTRIBUTED TO THE ANTITUBULIN CHEMOTHERAPEUTICS-INDUCED PERSISTENT PAIN. 2017 15 4637 31 NEURON-RESTRICTIVE SILENCER FACTOR CAUSES EPIGENETIC SILENCING OF KV4.3 GENE AFTER PERIPHERAL NERVE INJURY. PERIPHERAL NERVE INJURY CAUSES A VARIETY OF ALTERATIONS IN PAIN-RELATED GENE EXPRESSION IN PRIMARY AFFERENT, WHICH UNDERLIE THE NEURONAL PLASTICITY IN NEUROPATHIC PAIN. ONE OF THE CHARACTERISTIC ALTERATIONS IS A LONG-LASTING DOWNREGULATION OF VOLTAGE-GATED POTASSIUM (K(V)) CHANNEL, INCLUDING K(V)4.3, IN THE DORSAL ROOT GANGLION (DRG). THE PRESENT STUDY SHOWED THAT NERVE INJURY REDUCES THE MESSENGER RNA (MRNA) EXPRESSION LEVEL OF K(V)4.3 GENE, WHICH CONTAINS A CONSERVED NEURON-RESTRICTIVE SILENCER ELEMENT (NRSE), A BINDING SITE FOR NEURON-RESTRICTIVE SILENCER FACTOR (NRSF). MOREOVER, WE FOUND THAT INJURY CAUSES AN INCREASE IN DIRECT NRSF BINDING TO K(V)4.3-NRSE IN THE DRG, USING CHROMATIN IMMUNOPRECIPITATION (CHIP) ASSAY. CHIP ASSAY FURTHER REVEALED THAT ACETYLATION OF HISTONE H4, BUT NOT H3, AT K(V)4.3-NRSE IS MARKEDLY REDUCED AT DAY 7 POST-INJURY. FINALLY, THE INJURY-INDUCED K(V)4.3 DOWNREGULATION WAS SIGNIFICANTLY BLOCKED BY ANTISENSE-KNOCKDOWN OF NRSF. TAKEN TOGETHER, THESE DATA SUGGEST THAT NERVE INJURY CAUSES AN EPIGENETIC SILENCING OF K(V)4.3 GENE MEDIATED THROUGH TRANSCRIPTIONAL SUPPRESSOR NRSF IN THE DRG. 2010 16 1630 30 DNMT3A CONTRIBUTES TO THE DEVELOPMENT AND MAINTENANCE OF BONE CANCER PAIN BY SILENCING KV1.2 EXPRESSION IN SPINAL CORD DORSAL HORN. METASTATIC BONE TUMOR-INDUCED CHANGES IN GENE TRANSCRIPTION AND TRANSLATION IN PAIN-RELATED REGIONS OF THE NERVOUS SYSTEM MAY PARTICIPATE IN THE DEVELOPMENT AND MAINTENANCE OF BONE CANCER PAIN. EPIGENETIC MODIFICATIONS INCLUDING DNA METHYLATION REGULATE GENE TRANSCRIPTION. HERE, WE REPORT THAT INTRATHECAL INJECTION OF DECITABINE, A DNA METHYLTRANSFERASE (DNMT) INHIBITOR, DOSE DEPENDENTLY ATTENUATED THE DEVELOPMENT AND MAINTENANCE OF BONE CANCER PAIN INDUCED BY INJECTING PROSTATE CANCER CELLS INTO THE TIBIA. THE LEVEL OF THE DE NOVO DNMT3A, BUT NOT DNMT3B, TIME DEPENDENTLY INCREASED IN THE IPSILATERAL L4/5 DORSAL HORN (NOT L4/5 DORSAL ROOT GANGLION) AFTER PROSTATE CANCER CELLS INJECTION. BLOCKING THIS INCREASE THROUGH MICROINJECTION OF RECOMBINANT ADENO-ASSOCIATED VIRUS 5 (AAV5) EXPRESSING DNMT3A SHRNA INTO DORSAL HORN RESCUED PROSTATE CANCER CELLS-INDUCED DOWNREGULATION OF DORSAL HORN KV1.2 EXPRESSION AND IMPAIRED PROSTATE CANCER CELLS-INDUCED PAIN HYPERSENSITIVITY. IN TURN, MIMICKING THIS INCREASE THROUGH MICROINJECTION OF AAV5 EXPRESSING FULL-LENGTH DNMT3A INTO DORSAL HORN REDUCED DORSAL HORN KV1.2 EXPRESSION AND PRODUCED PAIN HYPERSENSITIVITY IN THE ABSENCE OF PROSTATE CANCER CELLS INJECTION. ADMINISTRATION OF NEITHER DECITABINE NOR VIRUS AFFECTED LOCOMOTOR FUNCTION AND ACUTE RESPONSES TO MECHANICAL, THERMAL, OR COLD STIMULI. GIVEN THAT DNMT3A MRNA IS CO-EXPRESSED WITH KCNA2 MRNA (ENCODING KV1.2) IN INDIVIDUAL DORSAL HORN NEURONS, OUR FINDINGS SUGGEST THAT INCREASED DORSAL HORN DNMT3A CONTRIBUTES TO BONE CANCER PAIN THROUGH SILENCING DORSAL HORN KV1.2 EXPRESSION. DNMT3A MAY REPRESENT A POTENTIAL NEW TARGET FOR CANCER PAIN MANAGEMENT. 2017 17 2253 35 EPIGENETIC MODULATION OF WNT SIGNALING CONTRIBUTES TO NEUROPATHIC PAIN IN RATS. PREVIOUS STUDIES HAVE DEMONSTRATED THAT THE WNT/BETA?CATENIN SIGNALING PATHWAY IS CRITICAL TO THE INDUCTION AND MAINTENANCE OF CHRONIC NEUROPATHIC PAIN CAUSED BY PERIPHERAL INFLAMMATION AND NERVE DAMAGE. EMERGING EVIDENCE FROM RECENT STUDIES SUGGESTS THAT EPIGENETIC MECHANISMS MAY ALSO BE CRITICAL TO THE PATHOGENESIS OF CHRONIC PAIN. THE PRESENT STUDY AIMED TO ELUCIDATE THE EPIGENETIC MECHANISMS UNDERLYING ALTERED WNT SIGNALING AND THEIR INVOLVEMENT IN CCI?INDUCED NEUROPATHIC PAIN IN RAT SCIATIC NERVES. THE RESULTS OF THE PRESENT STUDY DEMONSTRATED A SIGNIFICANT INCREASE IN THE EXPRESSION LEVELS OF WNT3A IN THE DORSAL HORN OF THE RATS WITH CCI. IN ADDITION, A SIGNIFICANT INCREASE IN HISTONE H3 ACETYLATION, AND A SIGNIFICANT DECREASE IN CYTOSINE METHYLATION IN THE PROMOTER REGION OF WNT3A WAS OBSERVED IN THE DORSAL HORN OF THE RATS WITH CCI. INTRATHECAL APPLICATION OF XAV939, WHICH ACTS AS AN INHIBITOR OF WNT SIGNALING, SIGNIFICANTLY DECREASED THE EXPRESSION LEVELS OF ACTIVE BETA?CATENIN, AND ATTENUATED THE RAT BEHAVIORAL RESPONSES TO THERMAL AND MECHANICAL PAIN STIMULI. THESE RESULTS SUGGEST THAT THE EPIGENETIC UPREGULATION OF WNT3A IN THE DORSAL HORN CONTRIBUTES TO THE MAINTENANCE OF PAIN?INDUCED BEHAVIOR IN RATS WITH CCI. 2015 18 6172 32 THE HDAC1/C-JUN COMPLEX IS ESSENTIAL IN THE PROMOTION OF NERVE INJURY-INDUCED NEUROPATHIC PAIN THROUGH JNK SIGNALING. HISTONE DEACETYLASE INHIBITORS (HDACIS) INTERFERE WITH THE EPIGENETIC PROCESS OF HISTONE ACETYLATION AND ARE KNOWN TO HAVE ANALGESIC PROPERTIES IN MODELS OF CHRONIC INFLAMMATORY PAIN. ADMINISTRATION OF A SELECTIVE HDAC1 INHIBITOR (LG325) IN SNI-SUBJECTED MICE SIGNIFICANTLY ATTENUATED BEHAVIOR RELATED TO INJURY-INDUCED PAIN. UNDERSTANDING THE HDAC1 PATHWAY IN EPIGENETIC REGULATION OF PATHOLOGICAL PAIN IS OF GREAT MEDICAL RELEVANCE. SPARED NERVE INJURY (SNI) MICE SHOWED A SIGNIFICANT INCREASE IN THE HDAC1 PROTEIN LEVELS WITHIN SPINAL CORD IN COINCIDENCE WITH THE NOCICEPTIVE PHENOTYPE AT 1 AND 3 WEEKS AFTER NERVE INJURY. NO VARIATION IN HDAC3, DNMT3A, ACH3, MBD3 AND MECP2 LEVELS WAS DETECTED. INCREASED EXPRESSION OF HDAC1 IS ACCOMPANIED BY ACTIVATION OF THE JNK-C-JUN SIGNALING PATHWAY. A ROBUST SPINAL JNK-1 OVERPHOSPHORYLATION WAS OBSERVED POST NERVE-INJURY ALONG WITH A SELECTIVE JNK-DEPENDENT INCREASE IN P-C-JUN AND HDAC1 PROTEIN LEVELS. CO-IMMUNOPRECIPITATION EXPERIMENTS SHOWED THE PRESENCE OF A HETERODIMERIC COMPLEX BETWEEN HDAC1 AND C-JUN IN SNI MICE INDICATING THAT THESE TRANSCRIPTION FACTORS CAN ACT TOGETHER TO REGULATE TRANSCRIPTION THROUGH HETERODIMERIZATION. STIMULATION OF C-JUN PHOSPHORYLATION WAS PREVENTED BY THE SELECTIVE HDAC1 INHIBITOR LG325. WE FOUND THAT HDAC1 WAS ASSOCIATED WITH C-JUN IN NUCLEI OF SPINAL DORSAL HORN ASTROCYTES EXPRESSING JNK. ON THE OTHER HAND, THE PRESENCE OF HDAC1 AND C-JUN INTERACTION WAS NOT DETECTED IN CONTROL MICE. THESE FINDINGS PROVIDE NEW INSIGHTS INTO THE MECHANISMS UNDERLYING THE ANTI-NOCICEPTIVE ACTIVITY OF HDAC INHIBITORS. TAKEN TOGETHER, THESE DATA SUPPORT A ROLE FOR HISTONE DEACETYLASE IN THE EMERGENCE OF NEUROPATHIC PAIN. 2018 19 3194 27 HDAC INHIBITORS ATTENUATE THE DEVELOPMENT OF HYPERSENSITIVITY IN MODELS OF NEUROPATHIC PAIN. HISTONE DEACETYLASE INHIBITORS (HDACIS) INTERFERE WITH THE EPIGENETIC PROCESS OF HISTONE ACETYLATION AND ARE KNOWN TO HAVE ANALGESIC PROPERTIES IN MODELS OF CHRONIC INFLAMMATORY PAIN. THE AIM OF THIS STUDY WAS TO DETERMINE WHETHER THESE COMPOUNDS COULD ALSO AFFECT NEUROPATHIC PAIN. DIFFERENT CLASS I HDACIS WERE DELIVERED INTRATHECALLY INTO RAT SPINAL CORD IN MODELS OF TRAUMATIC NERVE INJURY AND ANTIRETROVIRAL DRUG-INDUCED PERIPHERAL NEUROPATHY (STAVUDINE, D4T). MECHANICAL AND THERMAL HYPERSENSITIVITY WAS ATTENUATED BY 40% TO 50% AS A RESULT OF HDACI TREATMENT, BUT ONLY IF STARTED BEFORE ANY INSULT. THE DRUGS GLOBALLY INCREASED HISTONE ACETYLATION IN THE SPINAL CORD, BUT APPEARED TO HAVE NO MEASURABLE EFFECTS IN RELEVANT DORSAL ROOT GANGLIA IN THIS TREATMENT PARADIGM, SUGGESTING THAT ANY POTENTIAL MECHANISM SHOULD BE SOUGHT IN THE CENTRAL NERVOUS SYSTEM. MICROARRAY ANALYSIS OF DORSAL CORD RNA REVEALED THE SIGNATURE OF THE SPECIFIC COMPOUND USED (MS-275) AND SUGGESTED THAT ITS MAIN EFFECT WAS MEDIATED THROUGH HDAC1. TAKEN TOGETHER, THESE DATA SUPPORT A ROLE FOR HISTONE ACETYLATION IN THE EMERGENCE OF NEUROPATHIC PAIN. 2013 20 3324 36 HISTONE DEACETYLASE 2 IS INVOLVED IN MICRO?OPIOID RECEPTOR SUPPRESSION IN THE SPINAL DORSAL HORN IN A RAT MODEL OF CHRONIC PANCREATITIS PAIN. CHRONIC PAIN OCCURS IN ~85-90% OF CHRONIC PANCREATITIS (CP) PATIENTS. HOWEVER, AS THE PATHOGENESIS OF CP PAIN REMAINS TO BE FULLY UNDERSTOOD, THE CURRENT THERAPIES FOR CP PAIN REMAIN INADEQUATE. EMERGING EVIDENCE HAS SUGGESTED THAT THE EPIGENETIC MODULATIONS OF GENES ARE INVOLVED IN CHRONIC PAIN. IN THE PRESENT STUDY, INTRAPANCREATIC TRINITROBENZENE SULFONIC ACID INFUSIONS WERE USED TO ESTABLISH A CP MODEL IN RATS. MECHANICAL ALLODYNIA WAS MEASURED WITH VON FREY FILAMENTS. IMMUNOFLUORESCENT STAINING ANALYSIS WAS USED TO OBSERVE THE EXPRESSION CHANGES OF HISTONE DEACETYLASE 2 (HDAC2) AND MICRO?OPIOID RECEPTOR (MOR), AND INTRATHECAL ADMINISTRATION OF THE SELECTIVE HDAC2 INHIBITOR AR?42 WAS USED TO ASSESS THE UNDERLYING MECHANISMS. THE EXPRESSION LEVELS OF C?JUN N?TERMINAL KINASE (JNK) IN THE THORACIC SPINAL CORD WERE DETECTED BY WESTERN BLOTTING, AND THE MRNA EXPRESSION LEVELS OF INTERLEUKIN (IL)1?BETA, IL?6 AND TUMOR NECROSIS FACTOR (TNF)?ALPHA WERE DETECTED BY REVERSE TRANSCRIPTION?QUANTITATIVE POLYMERASE CHAIN REACTION. THE RESULTS DEMONSTRATED THAT HDAC2 EXPRESSION WAS UPREGULATED DURING THE COURSE OF CP INDUCTION, WHILE MOR ACTIVITY IN THE THORACIC SPINAL DORSAL HORN WAS SIGNIFICANTLY SUPPRESSED. INTRATHECAL INFUSION OF AR?42 SIGNIFICANTLY ATTENUATED CP?INDUCED MECHANICAL ALLODYNIA, WITH RESCUED MOR ACTIVITY. ADDITIONALLY, HDAC2 FACILITATED THE RELEASE OF INFLAMMATORY CYTOKINES, INCLUDING IL?1BETA, IL?6 AND TNF?ALPHA. THESE RESULTS SUGGESTED THAT THE UNDERLYING MECHANISMS OF HDAC2 REGULATING MOR ACTIVITY UNDER CP INDUCTION MAY OCCUR VIA PROMOTING THE RELEASE OF INFLAMMATORY CYTOKINES, THUS ACTIVATING THE JNK SIGNALING PATHWAY. THE PRESENT STUDY SUGGESTED THAT THE EPIGENETIC?REGULATED DISTURBANCE OF MOR IS DEPENDENT ON THE ENDOGENOUS ANALGESIA SYSTEM IN CP, WHICH MAY A PROVIDE NOVEL THERAPEUTIC STRATEGY FOR TREATING PAIN IN CP. 2018