1 5977 110 TET1-TRPV4 SIGNALING CONTRIBUTES TO BONE CANCER PAIN IN RATS. BONE CANCER PAIN (BCP) IS EXCRUCIATING FOR CANCER PATIENTS, WITH LIMITED CLINICAL TREATMENT OPTIONS AND SIGNIFICANT SIDE EFFECTS, DUE TO THE COMPLEX AND UNCLEAR PATHOGENESIS OF BONE CANCER PAIN. PERIPHERAL SENSITIZATION IN DORSAL ROOT GANGLION (DRG) NEURONS IS A RECOGNIZED CELLULAR MECHANISM FOR BONE CANCER PAIN. THE PATHOLOGICAL MECHANISM OF CHRONIC PAIN IS INCREASINGLY BEING AFFECTED BY EPIGENETIC MECHANISMS. IN THIS STUDY, WE UNBIASEDLY SHOWED THAT THE DNA HYDROXYMETHYLASE TEN-ELEVEN TRANSLOCATION 1 (TET1) EXPRESSION WAS SIGNIFICANTLY INCREASED IN THE L4-6 DRG OF BCP RATS AND TEN-ELEVEN TRANSLOCATION 2 (TET2) EXPRESSION DID NOT CHANGE SIGNIFICANTLY. NOTABLY, TET1 INHIBITION BY INTRATHECAL INJECTION OF BOBCAT339 (A TET1 INHIBITOR) EFFECTIVELY RELIEVED MECHANICAL HYPERALGESIA IN BCP RATS. PERIPHERAL SENSITIZATION IN CHRONIC PAIN RELIES ON THE ACTIVATION AND OVEREXPRESSION OF ION CHANNELS ON NEURONS. HERE, WE DEMONSTRATED THAT TRPV4, ONE OF THE TRANSIENT RECEPTOR POTENTIAL ION CHANNEL FAMILY MEMBERS, WAS SIGNIFICANTLY ELEVATED IN THE L4-6 DRG OF BCP RATS. IN ADDITION, TRPV4 INHIBITION BY INTRATHECAL INJECTION OF HC067047 (A TRPV4 INHIBITOR) ALSO SIGNIFICANTLY ATTENUATED MECHANICAL HYPERALGESIA IN BCP RATS. INTERESTINGLY, WE FOUND THAT TET1 INHIBITION DOWNREGULATED TRPV4 EXPRESSION IN THE L4-6 DRG OF BCP RATS. AS A RESULT, THESE FINDINGS SUGGESTED THAT TET1 MAY CONTRIBUTE TO BONE CANCER PAIN BY UPREGULATING TRPV4 EXPRESSION IN THE L4-6 DRG OF BCP RATS AND THAT TET1 OR TRPV4 MAY BECOME THERAPEUTIC TARGETS FOR BONE CANCER PAIN. 2023 2 5865 37 SUPPRESSION OF HDAC2 IN SPINAL CORD ALLEVIATES MECHANICAL HYPERALGESIA AND RESTORES KCC2 EXPRESSION IN A RAT MODEL OF BONE CANCER PAIN. EPIGENETIC MODULATION PARTICIPATES IN THE MECHANISM OF MULTIPLE TYPES OF PATHOLOGICAL PAIN, SO TARGETING THE INVOLVED REGULATORS MAY BE A PROMISING STRATEGY FOR PAIN TREATMENT. OUR PREVIOUS RESEARCH IDENTIFIED THE ANALGESIC EFFECT OF THE HISTONE DEACETYLASE (HDAC) INHIBITOR TRICHOSTATIN A (TSA) ON MECHANICAL HYPERALGESIA IN A RAT MODEL OF BONE CANCER PAIN (BCP) VIA RESTORATION OF MU-OPIOID RECEPTOR (MOR) EXPRESSION. HOWEVER, THE SPECIFIC TYPES OF HDACS CONTRIBUTING TO BCP HAVE NOT BEEN EXPLORED. THE PRESENT STUDY INVESTIGATED THE EXPRESSION PATTERN OF SOME COMMON HDACS AND FOUND THAT HDAC2 WAS UP-REGULATED IN A TIME-DEPENDENT MANNER IN THE LUMBAR SPINAL CORD OF BCP RATS. TSA APPLICATION SUPPRESSED HDAC2 EXPRESSION IN CULTURED PC12 CELLS AND REVERSED THE AUGMENTED HDAC2 IN BCP RATS. AN RNA-INTERFERING STRATEGY CONFIRMED THE ESSENTIAL ROLE OF HDAC2 IN THE MODULATION OF MECHANICAL HYPERALGESIA FOLLOWING TUMOR CELL INOCULATION, AND WE FURTHER EXAMINED ITS POSSIBLE DOWNSTREAM TARGETS. NOTABLY, HDAC2 KNOCK-DOWN DID NOT RESTORE MOR EXPRESSION, BUT IT ROBUSTLY REVERSED THE DOWN-REGULATION OF POTASSIUM-CHLORIDE COTRANSPORTER 2 (KCC2). THE IMPAIRED KCC2 EXPRESSION IS A VITAL MECHANISM OF MANY TYPES OF PATHOLOGICAL PAIN. THEREFORE, OUR RESULTS DEMONSTRATED THAT HDAC2 IN SPINAL CORD CONTRIBUTED TO THE MECHANICAL HYPERALGESIA IN BCP RATS, AND THIS EFFECT MAY BE ASSOCIATED WITH KCC2 MODULATION. 2018 3 6664 35 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 4 3247 25 HEPATITIS B VIRUS BASAL CORE PROMOTER MUTATIONS SHOW LOWER REPLICATION FITNESS ASSOCIATED WITH CCCDNA ACETYLATION STATUS. IN CHRONIC HEPATITIS B VIRUS (HBV) INFECTION, VARIANTS WITH MUTATIONS IN THE BASAL CORE PROMOTER (BCP) AND PRECORE REGION PREDOMINATE AND ASSOCIATE WITH MORE SEVERE DISEASE FORMS. STUDIES ON THEIR EFFECT ON VIRAL REPLICATION REMAIN CONTROVERSIAL. INCREASING EVIDENCE SHOWS THAT EPIGENETIC MODIFICATIONS OF CCCDNA REGULATE HBV REPLICATION AND DISEASE OUTCOME. HERE WE DETERMINED THE TRANSCRIPTION AND VIRAL REPLICATION EFFICIENCY OF WELL-DEFINED BCP AND PRECORE MUTATIONS AND THEIR EFFECT ON CCCDNA EPIGENETIC CONTROL. HBV MONOMERS BEARING BCP MUTATIONS A1762T/G1764A AND A1762T/G1764A/C1766T, AND PRECORE MUTATIONS G1896A, G1899A AND G1896A/G1899A, WERE TRANSFECTED INTO HEPG2 CELLS USING A PLASMID-FREE APPROACH. VIRAL RNA TRANSCRIPTS WERE DETECTED BY NORTHERN BLOT HYBRIDIZATION AND RT PCR, DNA REPLICATIVE INTERMEDIATES BY SOUTHERN BLOTTING AND RT PCR, AND VIRAL RELEASE WAS MEASURED BY ELISA. ACETYLATION OF CCCDNA-BOUND HISTONES WAS ASSESSED BY CHROMATIN IMMUNOPRECIPITATION (CHIP) ASSAY AND METHYLATION OF CCCDNA BY BISULFITE SEQUENCING. BCP MUTATIONS RESULTED IN LOW VIRAL RELEASE, MRNA TRANSCRIPTION AND PGRNA/CCCDNA RATIOS THAT PARALLELED THE ACETYLATION OF CCCDNA-BOUND H4 HISTONE AND INVERSELY CORRELATED WITH THE HDAC1 RECRUITMENT ONTO CCCDNA. INDEPENDENTLY OF THE MUTATIONS, CCCDNA WAS A TARGET FOR METHYLATION, ACCOMPANIED BY THE UPREGULATION OF DNMT1 EXPRESSION AND DNMT1 RECRUITMENT ONTO CCCDNA. OUR RESULTS SUGGEST THAT BCP MUTATIONS DECREASE VIRAL REPLICATION CAPACITY POSSIBLY BY MODULATING THE ACETYLATION AND DEACETYLATION OF CCCDNA-BOUND HISTONES WHILE PRECORE MUTATIONS DO NOT HAVE A SIGNIFICANT EFFECT ON VIRAL REPLICATION. THESE DATA PROVIDE EVIDENCE THAT EPIGENETIC FACTORS CONTRIBUTE TO THE REGULATION OF HBV VIRAL REPLICATION. 2016 5 2452 34 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 6 4172 34 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 7 5574 36 ROLE OF MICRORNA-143 IN NERVE INJURY-INDUCED UPREGULATION OF DNMT3A EXPRESSION IN PRIMARY SENSORY NEURONS. PERIPHERAL NERVE INJURY INCREASED THE EXPRESSION OF THE DNA METHYLTRANSFERASE 3A (DNMT3A) MRNA AND ITS ENCODING DNMT3A PROTEIN IN INJURED DORSAL ROOT GANGLIA (DRG). THIS INCREASE IS CONSIDERED AS AN ENDOGENOUS INSTIGATOR IN NEUROPATHIC PAIN GENESIS THROUGH EPIGENETIC SILENCING OF PAIN-ASSOCIATED GENES (SUCH AS OPRM1) IN INJURED DRG. HOWEVER, HOW DRG DNMT3A IS INCREASED FOLLOWING PERIPHERAL NERVE INJURY IS STILL ELUSIVE. WE REPORTED HERE THAT PERIPHERAL NERVE INJURY CAUSED BY THE FIFTH SPINAL NERVE LIGATION (SNL) DOWNREGULATED MICRORNA (MIR)-143 EXPRESSION IN INJURED DRG. THIS DOWNREGULATION WAS REQUIRED FOR SNL-INDUCED DRG DNMT3A INCREASE AS RESCUING MIR-143 DOWNREGULATION THROUGH MICROINJECTION OF MIR-143 MIMICS INTO INJURED DRG BLOCKED THE SNL-INDUCED INCREASE IN DNMT3A AND RESTORED THE SNL-INDUCED DECREASES IN OPRM1 MRNA AND ITS ENCODING MU OPIOID RECEPTOR (MOR) IN INJURED DRG, IMPAIRED SPINAL CORD CENTRAL SENSITIZATION AND NEUROPATHIC PAIN, AND IMPROVED MORPHINE ANALGESIC EFFECTS FOLLOWING SNL. MIMICKING SNL-INDUCED DRG MIR-143 DOWNREGULATION THROUGH DRG MICROINJECTION OF MIR143 INHIBITORS IN NAIVE RATS INCREASED THE EXPRESSION OF DNMT3A AND REDUCED THE EXPRESSION OF OPRM1 MRNA AND MOR IN INJECTED DRG AND PRODUCED NEUROPATHIC PAIN-LIKE SYMPTOMS. THESE FINDINGS SUGGEST THAT MIR-143 IS A NEGATIVE REGULATOR IN DNMT3A EXPRESSION IN THE DRG UNDER NEUROPATHIC PAIN CONDITIONS AND MAY BE A POTENTIAL TARGET FOR THERAPEUTIC MANAGEMENT OF NEUROPATHIC PAIN. 2017 8 5780 26 SPINAL RNF20-MEDIATED HISTONE H2B MONOUBIQUITYLATION REGULATES MGLUR5 TRANSCRIPTION FOR NEUROPATHIC ALLODYNIA. TO DATE, HISTONE H2B MONOUBIQUITINATION (H2BUB), A MARK ASSOCIATED WITH TRANSCRIPTIONAL ELONGATION AND ONGOING TRANSCRIPTION, HAS NOT BEEN LINKED TO THE DEVELOPMENT OR MAINTENANCE OF NEUROPATHIC PAIN STATES. HERE, USING MALE SPRAGUE DAWLEY RATS, WE DEMONSTRATED SPINAL NERVE LIGATION (SNL) INDUCED BEHAVIORAL ALLODYNIA AND PROVOKED RING FINGER PROTEIN 20 (RNF20)-DEPENDENT H2BUB IN DORSAL HORN. MOREOVER, SNL PROVOKED RNF20-MEDIATED H2BUB PHOSPHORYLATED RNA POLYMERASE II (RNAPII) IN THE PROMOTER FRAGMENTS OF MGLUR5, THEREBY ENHANCING MGLUR5 TRANSCRIPTION/EXPRESSION IN THE DORSAL HORN. CONVERSELY, FOCAL KNOCKDOWN OF SPINAL RNF20 EXPRESSION REVERSED NOT ONLY SNL-INDUCED ALLODYNIA BUT ALSO RNF20/H2BUB/RNAPII PHOSPHORYLATION-ASSOCIATED SPINAL MGLUR5 TRANSCRIPTION/EXPRESSION. NOTABLY, TNF-ALPHA INJECTION INTO NAIVE RATS AND SPECIFIC NEUTRALIZING ANTIBODY INJECTION INTO SNL-INDUCED ALLODYNIA RATS REVEALED THAT TNF-ALPHA-ASSOCIATED ALLODYNIA INVOLVES THE RNF20/H2BUB/RNAPII TRANSCRIPTIONAL AXIS TO UPREGULATE MGLUR5 EXPRESSION IN THE DORSAL HORN. COLLECTIVELY, OUR FINDINGS INDICATED TNF-ALPHA INDUCES RNF20-DRIVED H2B MONOUBIQUITINATION, WHICH FACILITATES PHOSPHORYLATED RNAPII-DEPENDENT MGLUR5 TRANSCRIPTION IN THE DORSAL HORN FOR THE DEVELOPMENT OF NEUROPATHIC ALLODYNIA.SIGNIFICANCE STATEMENT HISTONE H2B MONOUBIQUITINATION (H2BUB), AN EPIGENETIC POST-TRANSLATIONAL MODIFICATION, POSITIVELY CORRELATED WITH GENE EXPRESSION. HERE, TNF-ALPHA PARTICIPATED IN NEUROPATHIC PAIN DEVELOPMENT BY ENHANCING RNF20-MEDIATED H2BUB, WHICH FACILITATES PHOSPHORYLATED RNAPII-DEPENDENT MGLUR5 TRANSCRIPTION IN DORSAL HORN. OUR FINDING POTENTIALLY IDENTIFIED NEUROPATHIC ALLODYNIA PATHOPHYSIOLOGICAL PROCESSES UNDERPINNING ABNORMAL NOCICEPTION PROCESSING AND OPENS A NEW AVENUE FOR THE DEVELOPMENT OF NOVEL ANALGESICS. 2018 9 1630 38 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 10 2751 31 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 11 2203 29 EPIGENETIC MODIFICATION OF SPINAL MIR-219 EXPRESSION REGULATES CHRONIC INFLAMMATION PAIN BY TARGETING CAMKIIGAMMA. EMERGING EVIDENCE HAS SHOWN THAT MIRNA-MEDIATED GENE EXPRESSION MODULATION CONTRIBUTES TO CHRONIC PAIN, BUT ITS FUNCTIONAL REGULATORY MECHANISM REMAINS UNKNOWN. HERE, WE FOUND THAT COMPLETE FREUND'S ADJUVANT (CFA)-INDUCED CHRONIC INFLAMMATION PAIN SIGNIFICANTLY REDUCED MIRNA-219 (MIR-219) EXPRESSION IN MICE SPINAL NEURONS. FURTHERMORE, THE EXPRESSION OF SPINAL CAMKIIGAMMA, AN EXPERIMENTALLY VALIDATED TARGET OF MIR-219, WAS INCREASED IN CFA MICE. OVEREXPRESSION OF SPINAL MIR-219 PREVENTED AND REVERSED THERMAL HYPERALGESIA AND MECHANICAL ALLODYNIA AND SPINAL NEURONAL SENSITIZATION INDUCED BY CFA. CONCURRENTLY, INCREASED EXPRESSION OF SPINAL CAMKIIGAMMA WAS REVERSED BY MIR-219 OVEREXPRESSION. DOWNREGULATION OF SPINAL MIR-219 IN NAIVE MICE INDUCED PAIN-RESPONSIVE BEHAVIORS AND INCREASED P-NMDAR1 EXPRESSION, WHICH COULD BE INHIBITED BY KNOCKDOWN OF CAMKIIGAMMA. BISULFITE SEQUENCING SHOWED THAT CFA INDUCED THE HYPERMETHYLATION OF CPG ISLANDS IN THE MIR-219 PROMOTER. TREATMENT WITH DEMETHYLATION AGENT 5'-AZA-2'-DEOXYCYTIDINE MARKEDLY ATTENUATED PAIN BEHAVIOR AND SPINAL NEURONAL SENSITIZATION, WHICH WAS ACCOMPANIED WITH THE INCREASE OF SPINAL MIR-219 AND DECREASE OF CAMKIIGAMMA EXPRESSION. TOGETHER, WE CONCLUDE THAT METHYLATION-MEDIATED EPIGENETIC MODIFICATION OF SPINAL MIR-219 EXPRESSION REGULATES CHRONIC INFLAMMATORY PAIN BY TARGETING CAMKIIGAMMA. 2014 12 2407 39 EPIGENETIC RESTORATION OF VOLTAGE-GATED POTASSIUM CHANNEL KV1.2 ALLEVIATES NERVE INJURY-INDUCED NEUROPATHIC PAIN. VOLTAGE-GATED POTASSIUM CHANNELS (KV) ARE IMPORTANT REGULATORS OF NEURONAL EXCITABILITY FOR ITS ROLE OF REGULATING RESTING MEMBRANE POTENTIAL AND REPOLARIZATION. RECENT STUDIES SHOW THAT KV CHANNELS PARTICIPATE IN NEUROPATHIC PAIN, BUT THE DETAILED UNDERLYING MECHANISMS ARE FAR FROM BEING CLEAR. IN THIS STUDY, WE USED SIRNA, MIR-137 AGOMIR, AND ANTAGOMIR TO REGULATE THE EXPRESSION OF KV1.2 IN SPINAL CORD AND DORSAL ROOT GANGLIA (DRG) OF NAIVE AND CHRONIC CONSTRICTION INJURY (CCI) RATS. KV CURRENTS AND NEURON EXCITABILITY IN DRG NEURONS WERE EXAMINED BY PATCH-CLAMP WHOLE-CELL RECORDING TO VERIFY THE CHANGE IN KV1.2 FUNCTION. THE RESULTS SHOWED THAT KV1.2 WAS DOWN-REGULATED IN DRG AND SPINAL DORSAL HORN (SDH) BY CCI. KNOCKDOWN OF KV1.2 BY INTRATHECALLY INJECTING KCNA2 SIRNA INDUCED SIGNIFICANT MECHANICAL AND THERMAL HYPERSENSITIVITY IN NAIVE RATS. CONCOMITANT WITH THE DOWN-REGULATION OF KV1.2 WAS AN INCREASE IN THE EXPRESSION OF THE MIR-137. THE TARGETING AND REGULATING OF MIR-137 ON KCNA2 WAS VERIFIED BY DUAL-LUCIFERASE REPORTER SYSTEM AND INTRATHECAL INJECTING MIR-137 AGOMIR. FURTHERMORE, RESCUING THE EXPRESSION OF KV1.2 IN CCI RATS, ACHIEVED THROUGH INHIBITING MIR-137, RESTORED THE ABNORMAL KV CURRENTS AND EXCITABILITY IN DRG NEURONS, AND ALLEVIATED MECHANICAL ALLODYNIA AND THERMAL HYPERALGESIA. THESE RESULTS INDICATE THAT THE MIR-137-MEDIATED KV1.2 IMPAIRMENT IS A CRUCIAL ETIOPATHOGENESIS FOR THE NERVE INJURY-INDUCED NEUROPATHIC PAIN AND CAN BE A NOVEL POTENTIAL THERAPEUTIC TARGET FOR NEUROPATHIC PAIN MANAGEMENT. 2021 13 2479 36 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 14 4176 36 MELATONIN RELIEVES NEUROPATHIC ALLODYNIA THROUGH SPINAL MT2-ENHANCED PP2AC AND DOWNSTREAM HDAC4 SHUTTLING-DEPENDENT EPIGENETIC MODIFICATION OF HMGB1 TRANSCRIPTION. MELATONIN (MLT; N-ACETYL-5-METHOXYTRYPTAMINE) EXHIBITS ANALGESIC PROPERTIES IN CHRONIC PAIN CONDITIONS. WHILE RESEARCHES LINKING MLT TO EPIGENETIC MECHANISMS HAVE GROWN EXPONENTIALLY OVER RECENT YEARS, VERY FEW STUDIES HAVE INVESTIGATED THE CONTRIBUTION OF MLT-ASSOCIATED EPIGENETIC MODIFICATION TO PAIN STATES. HERE, WE REPORT THAT TOGETHER WITH BEHAVIORAL ALLODYNIA, SPINAL NERVE LIGATION (SNL) INDUCED A DECREASE IN THE EXPRESSION OF CATALYTIC SUBUNIT OF PHOSPHATASE 2A (PP2AC) AND ENHANCED HISTONE DEACETYLASE 4 (HDAC4) PHOSPHORYLATION AND CYTOPLASMIC ACCUMULATION, WHICH EPIGENETICALLY ALLEVIATED HDAC4-SUPPRESSED HMGB1 GENE TRANSCRIPTION, RESULTING IN INCREASED HIGH-MOBILITY GROUP PROTEIN B1 (HMGB1) EXPRESSION SELECTIVELY IN THE IPSILATERAL DORSAL HORN OF RATS. FOCAL KNOCK-DOWN OF SPINAL PP2AC EXPRESSION ALSO RESULTED IN BEHAVIORAL ALLODYNIA IN ASSOCIATION WITH SIMILAR PROTEIN EXPRESSION AS OBSERVED WITH SNL. NOTABLY, INTRATHECAL ADMINISTRATION WITH MLT INCREASED PP2AC EXPRESSION, HDAC4 DEPHOSPHORYLATION AND NUCLEAR ACCUMULATION, RESTORED HDAC4-MEDIATED HMGB1 SUPPRESSION AND RELIEVED SNL-SENSITIZED BEHAVIORAL PAIN; THESE EFFECTS WERE ALL INHIBITED BY SPINAL INJECTION OF 4P-PDOT (A MT2 RECEPTOR ANTAGONIST, 30 MINUTES BEFORE MLT) AND OKADAIC ACID (OA, A PP2A INHIBITOR, 3 HR AFTER MLT). OUR FINDINGS DEMONSTRATE A NOVEL MECHANISM BY WHICH MLT AMELIORATES NEUROPATHIC ALLODYNIA VIA EPIGENETIC MODIFICATION. THIS MLT-EXHIBITED ANTI-ALLODYNIA IS MEDIATED BY MT2-ENHANCED PP2AC EXPRESSION THAT COUPLES PP2AC WITH HDAC4 TO INDUCE HDAC4 DEPHOSPHORYLATION AND NUCLEAR IMPORT, HEREIN INCREASES HDAC4 BINDING TO THE PROMOTER OF HMGB1 GENE AND UPREGULATES HMGB1 EXPRESSION IN DORSAL HORN NEURONS. 2016 15 6767 30 ZNF382 CONTROLS MOUSE NEUROPATHIC PAIN VIA SILENCER-BASED EPIGENETIC INHIBITION OF CXCL13 IN DRG NEURONS. NERVE INJURY-INDUCED CHANGES OF GENE EXPRESSION IN DORSAL ROOT GANGLION (DRG) ARE CRITICAL FOR NEUROPATHIC PAIN GENESIS. HOWEVER, HOW THESE CHANGES OCCUR REMAINS ELUSIVE. HERE WE REPORT THE DOWN-REGULATION OF ZINC FINGER PROTEIN 382 (ZNF382) IN INJURED DRG NEURONS AFTER NERVE INJURY. RESCUING THIS DOWN-REGULATION ATTENUATES NOCICEPTIVE HYPERSENSITIVITY. CONVERSELY, MIMICKING THIS DOWN-REGULATION PRODUCES NEUROPATHIC PAIN SYMPTOMS, WHICH ARE ALLEVIATED BY C-X-C MOTIF CHEMOKINE 13 (CXCL13) KNOCKDOWN OR ITS RECEPTOR CXCR5 KNOCKOUT. MECHANISTICALLY, AN IDENTIFIED CIS-ACTING SILENCER AT DISTAL UPSTREAM OF THE CXCL13 PROMOTER SUPPRESSES CXCL13 TRANSCRIPTION VIA BINDING TO ZNF382. BLOCKING THIS BINDING OR GENETICALLY DELETING THIS SILENCER ABOLISHES THE ZNF382 SUPPRESSION ON CXCL13 TRANSCRIPTION AND IMPAIRS ZNF382-INDUCED ANTINOCICEPTION. MOREOVER, ZNF382 DOWN-REGULATION DISRUPTS THE REPRESSIVE EPIGENETIC COMPLEX CONTAINING HISTONE DEACETYLASE 1 AND SET DOMAIN BIFURCATED 1 AT THE SILENCER-PROMOTER LOOP, RESULTING IN CXCL13 TRANSCRIPTIONAL ACTIVATION. THUS, ZNF382 DOWN-REGULATION IS REQUIRED FOR NEUROPATHIC PAIN LIKELY THROUGH SILENCER-BASED EPIGENETIC DISINHIBITION OF CXCL13, A KEY NEUROPATHIC PAIN PLAYER, IN DRG NEURONS. 2021 16 4366 28 MIRNA-23A/CXCR4 REGULATES NEUROPATHIC PAIN VIA DIRECTLY TARGETING TXNIP/NLRP3 INFLAMMASOME AXIS. BACKGROUND: CHEMOKINE CXC RECEPTOR 4 (CXCR4) IN SPINAL GLIAL CELLS HAS BEEN IMPLICATED IN NEUROPATHIC PAIN. HOWEVER, THE REGULATORY CASCADES OF CXCR4 IN NEUROPATHIC PAIN REMAIN ELUSIVE. HERE, WE INVESTIGATED THE FUNCTIONAL REGULATORY ROLE OF MIRNAS IN THE PAIN PROCESS AND ITS INTERPLAY WITH CXCR4 AND ITS DOWNSTREAM SIGNALING. METHODS: MIRNAS AND CXCR4 AND ITS DOWNSTREAM SIGNALING MOLECULES WERE MEASURED IN THE SPINAL CORDS OF MICE WITH SCIATIC NERVE INJURY VIA PARTIAL SCIATIC NERVE LIGATION (PSNL). IMMUNOBLOTTING, IMMUNOFLUORESCENCE, IMMUNOPRECIPITATION, AND MAMMAL TWO-HYBRID AND BEHAVIORAL TESTS WERE USED TO EXPLORE THE DOWNSTREAM CXCR4-DEPENDENT SIGNALING PATHWAY. RESULTS: CXCR4 EXPRESSION INCREASED IN SPINAL GLIAL CELLS OF MICE WITH PSNL-INDUCED NEUROPATHIC PAIN. BLOCKING CXCR4 ALLEVIATED THE PAIN BEHAVIOR; CONTRARILY, OVEREXPRESSING CXCR4 INDUCED PAIN HYPERSENSITIVITY. MICRORNA-23A-3P (MIR-23A) DIRECTLY BOUNDS TO 3' UTR OF CXCR4 MRNA. PSNL-INDUCED NEUROPATHIC PAIN SIGNIFICANTLY REDUCED MRNA EXPRESSION OF MIR-23A. OVEREXPRESSION OF MIR-23A BY INTRATHECAL INJECTION OF MIR-23A MIMICS OR LENTIVIRUS REDUCED SPINAL CXCR4 AND PREVENTED PSNL-INDUCED NEUROPATHIC PAIN. IN CONTRAST, KNOCKDOWN OF MIR-23A BY INTRATHECAL INJECTION OF MIR-23A INHIBITOR OR LENTIVIRUS INDUCED PAIN-LIKE BEHAVIOR, WHICH WAS REDUCED BY CXCR4 INHIBITION. ADDITIONALLY, MIR-23A KNOCKDOWN OR CXCR4 OVEREXPRESSION IN NAIVE MICE COULD INCREASE THE THIOREDOXIN-INTERACTING PROTEIN (TXNIP), WHICH WAS ASSOCIATED WITH INDUCTION OF NOD-LIKE RECEPTOR PROTEIN 3 (NLRP3) INFLAMMASOME. INDEED, CXCR4 AND TXNIP WERE CO-EXPRESSED. THE MAMMAL TWO-HYBRID ASSAY REVEALED THE DIRECT INTERACTION BETWEEN CXCR4 AND TXNIP, WHICH WAS INCREASED IN THE SPINAL CORD OF PSNL MICE. IN PARTICULAR, INHIBITION OF TXNIP REVERSED PAIN BEHAVIOR ELICITED BY PSNL, MIR-23A KNOCKDOWN, OR CXCR4 OVEREXPRESSION. MOREOVER, MIR-23A OVEREXPRESSION OR CXCR4 KNOCKDOWN INHIBITED THE INCREASE OF TXNIP AND NLRP3 INFLAMMASOME IN PSNL MICE. CONCLUSIONS: MIR-23A, BY DIRECTLY TARGETING CXCR4, REGULATES NEUROPATHIC PAIN VIA TXNIP/NLRP3 INFLAMMASOME AXIS IN SPINAL GLIAL CELLS. EPIGENETIC INTERVENTIONS AGAINST MIR-23A, CXCR4, OR TXNIP MAY POTENTIALLY SERVE AS NOVEL THERAPEUTIC AVENUES IN TREATING PERIPHERAL NERVE INJURY-INDUCED NOCICEPTIVE HYPERSENSITIVITY. 2018 17 3433 38 HYDROXYMETHYLATION OF MICRORNA-365-3P REGULATES NOCICEPTIVE BEHAVIORS VIA KCNH2. DNA 5-HYDROXYLMETHYLCYTOSINE (5HMC) CATALYZED BY TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE (TET) OCCURS ABUNDANTLY IN NEURONS OF MAMMALS. HOWEVER, THE IN VIVO CAUSAL LINK BETWEEN TET DYSREGULATION AND NOCICEPTIVE MODULATION HAS NOT BEEN ESTABLISHED. HERE, WE FOUND THAT SPINAL TET1 AND TET3 WERE SIGNIFICANTLY INCREASED IN THE MODEL OF FORMALIN-INDUCED ACUTE INFLAMMATORY PAIN, WHICH WAS ACCOMPANIED WITH THE AUGMENT OF GENOME-WIDE 5HMC CONTENT IN SPINAL CORD. KNOCKDOWN OF SPINAL TET1 OR TET3 ALLEVIATED THE FORMALIN-INDUCED NOCICEPTIVE BEHAVIOR AND OVEREXPRESSION OF SPINAL TET1 OR TET3 IN NAIVE MICE PRODUCED PAIN-LIKE BEHAVIOR AS EVIDENCED BY DECREASED THERMAL PAIN THRESHOLD. FURTHERMORE, WE FOUND THAT TET1 OR TET3 REGULATED THE NOCICEPTIVE BEHAVIOR BY TARGETING MICRORNA-365-3P (MIR-365-3P). FORMALIN INCREASED 5HMC IN THE MIR-365-3P PROMOTER, WHICH WAS INHIBITED BY KNOCKDOWN OF TET1 OR TET3 AND MIMICKED BY OVEREXPRESSION OF TET1 OR TET3 IN NAIVE MICE. NOCICEPTIVE BEHAVIOR INDUCED BY FORMALIN OR OVEREXPRESSION OF SPINAL TET1 OR TET3 COULD BE PREVENTED BY DOWNREGULATION OF MIR-365-3P, AND MIMICKED BY OVEREXPRESSION OF SPINAL MIR-365-3P. FINALLY, WE DEMONSTRATED THAT A POTASSIUM CHANNEL, VOLTAGE-GATED EAG-RELATED SUBFAMILY H MEMBER 2 (KCNH2), VALIDATED AS A TARGET OF MIR-365-3P, PLAYED A CRITICAL ROLE IN NOCICEPTIVE MODULATION BY SPINAL TET OR MIR-365-3P. TOGETHER, WE CONCLUDED THAT TET-MEDIATED HYDROXYMETHYLATION OF MIR-365-3P REGULATES NOCICEPTIVE BEHAVIOR VIA KCNH2. SIGNIFICANCE STATEMENT: MOUNTING EVIDENCE INDICATES THAT EPIGENETIC MODIFICATIONS IN THE NOCICEPTIVE PATHWAY CONTRIBUTE TO PAIN PROCESSES AND ANALGESIA RESPONSE. HERE, WE FOUND THAT THE INCREASE OF 5HMC CONTENT MEDIATED BY TET1 OR TET3 IN MIR-365-3P PROMOTER IN THE SPINAL CORD IS INVOLVED IN NOCICEPTIVE MODULATION THROUGH TARGETING A POTASSIUM CHANNEL, KCNH2. OUR STUDY REVEALS A NEW EPIGENETIC MECHANISM UNDERLYING NOCICEPTIVE INFORMATION PROCESSING, WHICH MAY BE A NOVEL TARGET FOR DEVELOPMENT OF ANTINOCICEPTIVE DRUGS. 2016 18 2885 34 G9A PARTICIPATES IN NERVE INJURY-INDUCED KCNA2 DOWNREGULATION IN PRIMARY SENSORY NEURONS. NERVE INJURY-INDUCED DOWNREGULATION OF VOLTAGE-GATED POTASSIUM CHANNEL SUBUNIT KCNA2 IN THE DORSAL ROOT GANGLION (DRG) IS CRITICAL FOR DRG NEURONAL EXCITABILITY AND NEUROPATHIC PAIN GENESIS. HOWEVER, HOW NERVE INJURY CAUSES THIS DOWNREGULATION IS STILL ELUSIVE. EUCHROMATIC HISTONE-LYSINE N-METHYLTRANSFERASE 2, ALSO KNOWN AS G9A, METHYLATES HISTONE H3 ON LYSINE RESIDUE 9 TO PREDOMINANTLY PRODUCE A DYNAMIC HISTONE DIMETHYLATION, RESULTING IN CONDENSED CHROMATIN AND GENE TRANSCRIPTIONAL REPRESSION. WE SHOWED HERE THAT BLOCKING NERVE INJURY-INDUCED INCREASE IN G9A RESCUED KCNA2 MRNA AND PROTEIN EXPRESSION IN THE AXOTOMIZED DRG AND ATTENUATED THE DEVELOPMENT OF NERVE INJURY-INDUCED PAIN HYPERSENSITIVITY. MIMICKING THIS INCREASE DECREASED KCNA2 MRNA AND PROTEIN EXPRESSION, REDUCED KV CURRENT, AND INCREASED EXCITABILITY IN THE DRG NEURONS AND LED TO SPINAL CORD CENTRAL SENSITIZATION AND NEUROPATHIC PAIN-LIKE SYMPTOMS. G9A MRNA IS CO-LOCALIZED WITH KCNA2 MRNA IN THE DRG NEURONS. THESE FINDINGS INDICATE THAT G9A CONTRIBUTES TO NEUROPATHIC PAIN DEVELOPMENT THROUGH EPIGENETIC SILENCING OF KCNA2 IN THE AXOTOMIZED DRG. 2016 19 1167 38 CONTRIBUTION OF DORSAL ROOT GANGLION OCTAMER TRANSCRIPTION FACTOR 1 TO NEUROPATHIC PAIN AFTER PERIPHERAL NERVE INJURY. NEUROPATHIC PAIN GENESIS IS RELATED TO GENE ALTERATIONS IN THE DORSAL ROOT GANGLION (DRG) AFTER PERIPHERAL NERVE INJURY. TRANSCRIPTION FACTORS CONTROL GENE EXPRESSION. IN THIS STUDY, WE INVESTIGATED WHETHER OCTAMER TRANSCRIPTION FACTOR 1 (OCT1), A TRANSCRIPTION FACTOR, CONTRIBUTED TO NEUROPATHIC PAIN CAUSED BY CHRONIC CONSTRICTION INJURY (CCI) OF THE SCIATIC NERVE. CHRONIC CONSTRICTION INJURY PRODUCED A TIME-DEPENDENT INCREASE IN THE LEVEL OF OCT1 PROTEIN IN THE IPSILATERAL L4/5 DRG, BUT NOT IN THE SPINAL CORD. BLOCKING THIS INCREASE THROUGH MICROINJECTION OF OCT1 SIRNA INTO THE IPSILATERAL L4/5 DRG ATTENUATED THE INITIATION AND MAINTENANCE OF CCI-INDUCED MECHANICAL ALLODYNIA, HEAT HYPERALGESIA, AND COLD ALLODYNIA AND IMPROVED MORPHINE ANALGESIA AFTER CCI, WITHOUT AFFECTING BASAL RESPONSES TO ACUTE MECHANICAL, HEAT, AND COLD STIMULI AS WELL AS LOCOMOTOR FUNCTIONS. MIMICKING THIS INCREASE THROUGH MICROINJECTION OF RECOMBINANT ADENO-ASSOCIATED VIRUS 5 HARBORING FULL-LENGTH OCT1 INTO THE UNILATERAL L4/5 DRG LED TO MARKED MECHANICAL ALLODYNIA, HEAT HYPERALGESIA, AND COLD ALLODYNIA IN NAIVE RATS. MECHANISTICALLY, OCT1 PARTICIPATED IN CCI-INDUCED INCREASES IN DNMT3A MRNA AND ITS PROTEIN AND DNMT3A-MEDIATED DECREASES IN OPRM1 AND KCNA2 MRNAS AND THEIR PROTEINS IN THE INJURED DRG. THESE FINDINGS INDICATE THAT OCT1 MAY PARTICIPATE IN NEUROPATHIC PAIN AT LEAST IN PART BY TRANSCRIPTIONALLY ACTIVATING DNMT3A AND SUBSEQUENTLY EPIGENETIC SILENCING OF OPRM1 AND KCAN2 IN THE DRG. OCT1 MAY SERVE AS A POTENTIAL TARGET FOR THERAPEUTIC TREATMENTS AGAINST NEUROPATHIC PAIN. 2019 20 3196 22 HDAC INHIBITORS RESTORE C-FIBRE SENSITIVITY IN EXPERIMENTAL NEUROPATHIC PAIN MODEL. BACKGROUND AND PURPOSE: HYPOESTHESIA IS A CLINICAL FEATURE OF NEUROPATHIC PAIN. THE FEATURE IS PARTLY EXPLAINED BY THE EVIDENCE OF EPIGENETIC REPRESSION OF NAV 1.8 SODIUM CHANNEL IN THE DORSAL ROOT GANGLION (DRG). EXPERIMENTAL APPROACH: WE INVESTIGATED THE POSSIBILITY OF TRICHOSTATIN A (TSA), VALPROIC ACID (VPA) AND SUBEROYLANILIDE HYDROXAMIC ACID (SAHA) TO REVERSE THE UNIQUE C-FIBRE SENSITIVITY OBSERVED FOLLOWING PARTIAL LIGATION OF SCIATIC NERVE IN MICE. KEY RESULTS: NERVE INJURY-INDUCED DOWN-REGULATION OF DRG NAV 1.8 SODIUM CHANNEL AND C-FIBRE-RELATED HYPOESTHESIA WERE REVERSED BY TSA, VPA AND SAHA TREATMENTS, WHICH INHIBIT HISTONE DEACETYLASE (HDAC), AND INCREASE HISTONE ACETYLATION AT THE REGULATORY SEQUENCE OF NAV 1.8. CONCLUSIONS AND IMPLICATIONS: TAKEN TOGETHER, THESE STUDIES PROVIDE THE EVIDENCE THAT HYPOESTHESIA AND UNDERLYING DOWN-REGULATION OF NAV 1.8, NEGATIVE SYMPTOMS OBSERVED IN NERVE INJURY-INDUCED NEUROPATHIC PAIN MODELS ARE REGULATED BY AN EPIGENETIC CHROMATIN REMODELLING THROUGH HDAC-RELATED MACHINERIES. 2013