1 809 139 CHANGES IN CLASS I AND IIB HDACS BY DELTA-OPIOID IN CHRONIC RAT GLAUCOMA MODEL. PURPOSE: THIS STUDY DETERMINES IF DELTA-OPIOID RECEPTOR AGONIST (I.E. SNC-121)-INDUCED EPIGENETIC CHANGES VIA REGULATION OF HISTONE DEACETYLASES (HDACS) FOR RETINAL GANGLION CELL (RGC) NEUROPROTECTION IN GLAUCOMA MODEL. METHODS: INTRAOCULAR PRESSURE WAS RAISED IN RAT EYES BY INJECTING 2M HYPERTONIC SALINE INTO THE LIMBAL VEINS. SNC-121 (1 MG/KG; I.P.) WAS ADMINISTERED TO THE ANIMALS FOR 7 DAYS. RETINAS WERE COLLECTED AT DAYS 7 AND 42, POST-INJURY FOLLOWED BY MEASUREMENT OF HDAC ACTIVITIES, MRNA, AND PROTEIN EXPRESSION BY ENZYME ASSAY, QUANTITATIVE REAL-TIME PCR (QRT-PCR), WESTERN BLOTTING, AND IMMUNOHISTOCHEMISTRY. RESULTS: THE VISUAL ACUITY, CONTRAST SENSITIVITY, AND PATTERN ELECTRORETINOGRAMS (ERGS) WERE DECLINED IN OCULAR HYPERTENSIVE ANIMALS, WHICH WERE SIGNIFICANTLY IMPROVED BY SNC-121 TREATMENT. CLASS I AND IIB HDACS ACTIVITIES WERE SIGNIFICANTLY INCREASED AT DAYS 7 AND 42 IN OCULAR HYPERTENSIVE ANIMALS. THE MRNA AND PROTEIN EXPRESSION OF HDAC 1 WAS INCREASED BY 1.33 +/- 0.07-FOLD AND 20.2 +/- 2.7%, HDAC 2 BY 1.4 +/- 0.05-FOLD AND 17.0 +/- 2.4%, HDAC 3 BY 1.4 +/- 0.06-FOLD AND 17.4 +/- 3.4%, AND HDAC 6 BY 1.5 +/- 0.09-FOLD AND 15.1 +/- 3.3% AT DAY 7, POST-INJURY. BOTH THE MRNA AND PROTEIN EXPRESSION OF HDACS WERE POTENTIATED FURTHER AT DAY 42 IN OCULAR HYPERTENSIVE ANIMALS. HDAC ACTIVITIES, MRNA, AND PROTEIN EXPRESSION WERE BLOCKED BY SNC-121 TREATMENT AT DAYS 7 AND 42 IN OCULAR HYPERTENSIVE ANIMALS. CONCLUSIONS: DATA SUGGESTS THAT CLASS I AND IIB HDACS ARE ACTIVATED AND UPREGULATED DURING EARLY STAGES OF GLAUCOMA. EARLY INTERVENTION WITH DELTA-OPIOID RECEPTOR ACTIVATION RESULTED IN THE PROLONGED SUPPRESSION OF CLASS I AND IIB HDACS ACTIVITIES AND EXPRESSION, WHICH MAY, IN PART, PLAY A CRUCIAL ROLE IN RGC NEUROPROTECTION. 2020 2 193 22 ACETYLATION-MEDIATED EPIGENETIC REGULATION OF GLUCOCORTICOID RECEPTOR ACTIVITY: CIRCADIAN RHYTHM-ASSOCIATED ALTERATIONS OF GLUCOCORTICOID ACTIONS IN TARGET TISSUES. GLUCOCORTICOIDS INFLUENCE ORGAN FUNCTIONS THROUGH THE GLUCOCORTICOID RECEPTOR, A PROTEIN ACETYLATED AND DEACETYLATED BY SEVERAL HISTONE ACETYLTRANSFERASES AND DEACETYLASES. WE REPORTED THAT THE CIRCADIAN RHYTHM-RELATED TRANSCRIPTION FACTOR "CLOCK", A KEY COMPONENT OF THE BIOLOGICAL CLOCK WITH INHERENT HISTONE ACETYLTRANSFERASE ACTIVITY, ACETYLATES GLUCOCORTICOID RECEPTOR LYSINES WITHIN ITS HINGE REGION--A "LYSINE CLUSTER" CONTAINING A KXKK MOTIF--AND REPRESSES ITS TRANSCRIPTIONAL ACTIVITY. THIS CLOCK-INDUCED REPRESSION OF THE GLUCOCORTICOID RECEPTOR ACTIVITY IS INVERSELY PHASED TO THE DIURNALLY CIRCULATING GLUCOCORTICOIDS AND MAY ACT AS A LOCAL COUNTER REGULATORY MECHANISM TO THE ACTIONS OF THESE HORMONES. IMPORTANTLY, UNCOUPLING OF THE CENTRAL CLOCK-REGULATED HYPOTHALAMIC-PITUITARY-ADRENAL AXIS AND PERIPHERAL CLOCK-MEDIATED ALTERATIONS OF GLUCOCORTICOID ACTION, SUCH AS CHRONIC STRESS AND FREQUENT TRANS-TIME ZONE TRAVEL OR NIGHT-SHIFT WORK, MAY CAUSE FUNCTIONAL HYPERCORTISOLISM AND CONTRIBUTE TO VARIOUS PATHOLOGIES. THUS, ACETYLATION-MEDIATED EPIGENETIC REGULATION OF THE GLUCOCORTICOID RECEPTOR MAY BE ESSENTIAL FOR THE MAINTENANCE OF PROPER TIME-INTEGRATED GLUCOCORTICOID ACTION, SIGNIFICANTLY INFLUENCING HUMAN WELL-BEING AND LONGEVITY. 2011 3 1904 39 ENHANCED RETINAL GANGLION CELL SURVIVAL IN GLAUCOMA BY HYPOXIC POSTCONDITIONING AFTER DISEASE ONSET. THE NEUROPROTECTIVE EFFICACY OF ADAPTIVE EPIGENETICS, WHEREIN BENEFICIAL GENE EXPRESSION CHANGES ARE INDUCED BY NONHARMFUL "CONDITIONING" STIMULI, IS NOW WELL ESTABLISHED IN SEVERAL ACUTE, PRECLINICAL CENTRAL NERVOUS SYSTEM INJURY MODELS. RECENTLY, IN A MOUSE MODEL OF GLAUCOMA, WE DEMONSTRATED RETINAL GANGLION CELL (RGC) PROTECTION BY REPETITIVELY "PRECONDITIONING" WITH HYPOXIA PRIOR TO DISEASE ONSET, INDICATING AN EPIGENETIC APPROACH MAY ALSO YIELD BENEFITS IN CHRONIC NEURODEGENERATIVE DISEASE. HEREIN, WE DETERMINED WHETHER PRESENTING THE REPETITIVE HYPOXIC STIMULUS AFTER DISEASE INITIATION [REPETITIVE HYPOXIC "POSTCONDITIONING" (RH-POST)] COULD AFFORD SIMILAR FUNCTIONAL AND MORPHOLOGIC PROTECTION AGAINST GLAUCOMATOUS RGC INJURY. CHRONIC ELEVATIONS IN INTRAOCULAR PRESSURE (IOP) WERE INDUCED UNILATERALLY IN ADULT MALE C57BL/6 MICE BY EPISCLERAL VEIN LIGATION. MICE WERE RANDOMIZED TO AN RH-POST [1 H OF SYSTEMIC HYPOXIA (11% OXYGEN) EVERY OTHER DAY, STARTING 4 DAYS AFTER IOP ELEVATION] OR AN UNTREATED CONTROL GROUP. AFTER 3 WEEKS OF EXPERIMENTAL GLAUCOMA, THE 21-27% REDUCTION AND 5-25% PROLONGATION IN FLASH VISUAL-EVOKED POTENTIAL AMPLITUDES AND LATENCIES, RESPECTIVELY, AND THE 30% IMPAIRMENT IN VISUAL ACUITY WERE ROBUSTLY IMPROVED IN RH-POST-TREATED MICE, AS WAS THE 17% LOSS IN RGC SOMA NUMBER AND 20% REDUCTION IN AXON INTEGRITY. THESE PROTECTIVE EFFECTS WERE OBSERVED WITHOUT RH-POST AFFECTING IOP. THE PRESENT FINDINGS DEMONSTRATE THAT FUNCTIONAL AND MORPHOLOGIC PROTECTION OF RGCS CAN BE REALIZED BY STIMULATING EPIGENETIC RESPONSES DURING THE EARLY STAGES OF DISEASE, AND THUS CONSTITUTE A NEW CONCEPTUAL APPROACH TO GLAUCOMA THERAPEUTICS. 2015 4 3332 31 HISTONE DEACETYLASE INHIBITOR-INDUCED EMERGENCE OF SYNAPTIC DELTA-OPIOID RECEPTORS AND BEHAVIORAL ANTINOCICEPTION IN PERSISTENT NEUROPATHIC PAIN. THE EFFICACY OF OPIOIDS IN PATIENTS WITH CHRONIC NEUROPATHIC PAIN REMAINS CONTROVERSIAL. ALTHOUGH ACTIVATION OF DELTA-OPIOID RECEPTORS (DORS) IN THE BRAINSTEM REDUCES INFLAMMATION-INDUCED PERSISTENT HYPERALGESIA, IT IS NOT EFFECTIVE UNDER PERSISTENT NEUROPATHIC PAIN CONDITIONS AND THESE CLINICAL PROBLEMS REMAIN LARGELY UNKNOWN. IN THIS STUDY, BY USING A CHRONIC CONSTRICTION INJURY (CCI) OF THE SCIATIC NERVE IN RATS, WE FOUND THAT IN THE BRAINSTEM NUCLEUS RAPHE MAGNUS (NRM), DORS EMERGED ON THE SURFACE MEMBRANE OF CENTRAL SYNAPTIC TERMINALS ON DAY 3 AFTER CCI SURGERY AND DISAPPEARED ON DAY 14. HISTONE DEACETYLASE (HDAC) INHIBITORS MICROINJECTED INTO THE NRM IN VIVO INCREASED THE LEVEL OF SYNAPTOSOMAL DOR PROTEIN AND NRM INFUSION OF DOR AGONISTS PRODUCING AN ANTINOCICEPTIVE EFFECT IN A NERVE GROWTH FACTOR (NGF) SIGNALING-DEPENDENT MANNER. IN VITRO, IN CCI RAT SLICES INCUBATED WITH HDAC INHIBITORS, DOR AGONISTS SIGNIFICANTLY INHIBITED EPSCS. THIS EFFECT WAS BLOCKED BY TYROSINE RECEPTOR KINASE A ANTAGONISTS. CHROMATIN IMMUNOPRECIPITATION ANALYSIS REVEALED THAT NRM INFUSION OF HDAC INHIBITORS IN CCI RATS INCREASED THE LEVEL OF HISTONE H4 ACETYLATION AT NGF GENE PROMOTER REGIONS. NGF WAS INFUSED INTO THE NRM OR INCUBATED CCI RAT SLICES DROVE DORS TO THE SURFACE MEMBRANE OF SYNAPTIC TERMINALS. TAKEN TOGETHER, EPIGENETIC UPREGULATION OF NGF ACTIVITY BY HDAC INHIBITORS IN THE NRM PROMOTES THE TRAFFICKING OF DORS TO PAIN-MODULATING NEURONAL SYNAPSES UNDER NEUROPATHIC PAIN CONDITIONS, LEADING TO DELTA-OPIOID ANALGESIA. THESE FINDINGS INDICATE THAT THERAPEUTIC USE OF DOR AGONISTS COMBINED WITH HDAC INHIBITORS MIGHT BE EFFECTIVE IN CHRONIC NEUROPATHIC PAIN MANAGEMENTS. 2016 5 5780 21 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 6 2751 26 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 7 1167 27 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 8 532 22 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 9 2006 26 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 10 2898 28 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 11 6918 33 [WNT3A SIGNALING PATHWAY PLAYS A ROLE IN NEUROPATHIC PAIN THROUGH EPIGENETIC MODIFICATION OF JMJD6]. TO EXPLORE WHETHER WNT3A EXERTS A ROLE IN NEUROPATHIC PAIN THROUGH JUMONJI C DOMAIN 6 (JMJD6)-ASSOCIATED EPIGENETIC MODIFICATION. METHODS: SD RATS WERE DIVIDED INTO 4 GROUPS: A SHAM GROUP, A CHRONIC CONSTRICTION INJURY (CCI) GROUP, A CCI+NEGATIVE LENTIVIRAL EXPRESSION VECTOR (LV-NC) GROUP AND A CCI+LENTIVIRAL OVEREXPRESSION VECTOR (LV-JMJD6) GROUP. THE SCIATIC NERVE CCI MODEL OF SD RAT AND JMJD6 LENTIVIRAL EXPRESSION VECTOR WERE CONSTRUCTED. ON THE THIRD DAY AFTER CCI, THE INTRATHECAL CATHETER WAS PREPARED, AND 20 MUL OF NORMAL SALINE AND LENTIVIRUS-CONTAINING REAGENT (VIRUS TITER 1X108 TU/ML) WERE ADMINISTERED. THE RATS' PAW WITHDRAWAL MECHANICAL THRESHOLD (PWMT) AND PAW WITHDRAWAL THERMAL LATENCY (PWTL) WERE MONITORED, AND WESTERN BLOTTING WAS USED TO DETECT THE EXPRESSION OF WNT3A AND NR2B PROTEIN IN THE SPINAL CORD. CO-IMMUNOPRECIPITATION WAS APPLIED TO DETECT THE INTERACTION BETWEEN JMJD6 AND WNT3A. RESULTS: COMPARED WITH THE SHAM GROUP, THE PWMT OF THE RATS IN EACH GROUP AFTER CCI WAS SIGNIFICANTLY DECREASED AND THE PWTL WAS SIGNIFICANTLY SHORTENED (P<0.05). COMPARED WITH THE CCI GROUP AND THE CCI+LV-NC GROUP, PWMT IN THE CCI+LV-JMJD6 GROUP WAS INCREASED SIGNIFICANTLY ON THE 10TH DAY AND THE 14TH DAY AFTER CCI, AND THE PWTL WAS SIGNIFICANTLY PROLONGED ON THE 14TH DAY AFTER CCI (P<0.05). ON THE 14TH DAY AFTER CCI, THE EXPRESSION LEVELS OF WNT3A AND NR2B IN THE CCI GROUP AND THE CCI+LV-NC GROUP WERE SIGNIFICANTLY HIGHER THAN THOSE IN THE SHAM GROUP. AFTER INTRATHECAL INJECTION OF LENTIVIRAL VECTOR, WNT3A AND NR2B PROTEIN EXPRESSION LEVELS IN THE CCI+LV-JMJD6 GROUP WERE LOWER COMPARED WITH THE CCI+LV-NC GROUP (P<0.05). THE RESULTS OF CO-IMMUNOPRECIPITATION SHOWED NO DIRECT INTERACTION BETWEEN WNT3A AND JMJD6. CONCLUSION: WNT3A IS INVOLVED IN MEDIATING NEUROPATHIC PAIN, AND ITS EFFECT MAY BE RELATED TO THE EPIGENETIC MODIFICATION OF JMJD6, WHICH IS LIKELY REGULATED THROUGH INDIRECT INTERACTION. 2019 12 5401 31 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 13 2311 40 EPIGENETIC REGULATION OF CYTOSOLIC PHOSPHOLIPASE A2 IN SH-SY5Y HUMAN NEUROBLASTOMA CELLS. GROUP IVA CYTOSOLIC PHOSPHOLIPASE A2 (CPLA2 OR PLA2G4A) IS A KEY ENZYME THAT CONTRIBUTES TO INFLAMMATION VIA THE GENERATION OF ARACHIDONIC ACID AND EICOSANOIDS. WHILE MUCH IS KNOWN ABOUT REGULATION OF CPLA2 BY POSTTRANSLATIONAL MODIFICATION SUCH AS PHOSPHORYLATION, LITTLE IS KNOWN ABOUT ITS EPIGENETIC REGULATION. IN THIS STUDY, TREATMENT WITH HISTONE DEACETYLASE (HDAC) INHIBITORS, TRICHOSTATIN A (TSA), VALPROIC ACID, TUBACIN AND THE CLASS I HDAC INHIBITOR, MS-275, WERE FOUND TO INCREASE CPLA2ALPHA MESSENGER RNA (MRNA) EXPRESSION IN SH-SY5Y HUMAN NEUROBLASTOMA CELLS. CO-TREATMENT OF THE HISTONE ACETYLTRANSFERASE (HAT) INHIBITOR, ANACARDIC ACID, MODULATED UPREGULATION OF CPLA2ALPHA INDUCED BY TSA. SPECIFIC INVOLVEMENT OF CLASS I HDACS AND HAT IN CPLA2ALPHA REGULATION WAS FURTHER SHOWN, AND A TIP60-SPECIFIC HAT INHIBITOR, NU9056, MODULATED THE UPREGULATION OF CPLA2ALPHA INDUCED BY MS-275. IN ADDITION, CO-TREATMENT OF WITH HISTONE METHYLTRANSFERASE (HMT) INHIBITOR, 5'-DEOXY-5'-METHYLTHIOADENOSINE (MTA) SUPPRESSED TSA-INDUCED CPLA2ALPHA UPREGULATION. THE ABOVE CHANGES IN CPLA2 MRNA EXPRESSION WERE REFLECTED AT THE PROTEIN LEVEL BY WESTERN BLOTS AND IMMUNOCYTOCHEMISTRY. CHROMATIN IMMUNOPRECIPITATION (CHIP) SHOWED TSA INCREASED BINDING OF TRIMETHYLATED H3K4 TO THE PROXIMAL PROMOTER REGION OF THE CPLA2ALPHA GENE. CELL INJURY AFTER TSA TREATMENT AS INDICATED BY LACTATE DEHYDROGENASE (LDH) RELEASE WAS MODULATED BY ANACARDIC ACID, AND A ROLE OF CPLA2 IN MEDIATING TSA-INDUCED INJURY SHOWN, AFTER CO-INCUBATION WITH THE CPLA2 SELECTIVE INHIBITOR, ARACHIDONOYL TRIFLUOROMETHYL KETONE (AACOCF3). TOGETHER, RESULTS INDICATE EPIGENETIC REGULATION OF CPLA2 AND THE POTENTIAL OF SUCH REGULATION FOR TREATMENT OF CHRONIC INFLAMMATION. 2016 14 2479 26 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 3832 36 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 16 5354 22 RE1-SILENCING TRANSCRIPTION FACTOR CONTROLS THE ACUTE-TO-CHRONIC NEUROPATHIC PAIN TRANSITION AND CHRM2 RECEPTOR GENE EXPRESSION IN PRIMARY SENSORY NEURONS. NEUROPATHIC PAIN IS ASSOCIATED WITH PERSISTENT CHANGES IN GENE EXPRESSION IN PRIMARY SENSORY NEURONS, BUT THE UNDERLYING EPIGENETIC MECHANISMS THAT CAUSE THESE CHANGES REMAIN UNCLEAR. THE MUSCARINIC CHOLINERGIC RECEPTORS (MACHRS), PARTICULARLY THE M2 SUBTYPE (ENCODED BY THE CHOLINERGIC RECEPTOR MUSCARINIC 2 (CHRM2) GENE), ARE CRITICALLY INVOLVED IN THE REGULATION OF SPINAL NOCICEPTIVE TRANSMISSION. HOWEVER, LITTLE IS KNOWN ABOUT HOW CHRM2 EXPRESSION IS TRANSCRIPTIONALLY REGULATED. HERE WE SHOW THAT NERVE INJURY PERSISTENTLY INCREASED THE EXPRESSION OF RE1-SILENCING TRANSCRIPTION FACTOR (REST, ALSO KNOWN AS NEURON-RESTRICTIVE SILENCING FACTOR [NRSF]), A GENE-SILENCING TRANSCRIPTION FACTOR, IN THE DORSAL ROOT GANGLION (DRG). REMARKABLY, NERVE INJURY-INDUCED CHRONIC BUT NOT ACUTE PAIN HYPERSENSITIVITY WAS ATTENUATED IN MICE WITH REST KNOCKOUT IN DRG NEURONS. ALSO, SIRNA-MEDIATED REST KNOCKDOWN REVERSED NERVE INJURY-INDUCED CHRONIC PAIN HYPERSENSITIVITY IN RATS. NERVE INJURY PERSISTENTLY REDUCED CHRM2 EXPRESSION IN THE DRG AND DIMINISHED THE ANALGESIC EFFECT OF MUSCARINE. THE RE1 BINDING SITE ON THE CHRM2 PROMOTER IS REQUIRED FOR REST-MEDIATED CHRM2 REPRESSION, AND NERVE INJURY INCREASED THE ENRICHMENT OF REST IN THE CHRM2 PROMOTER IN THE DRG. FURTHERMORE, REST KNOCKDOWN OR GENETIC ABLATION IN DRG NEURONS NORMALIZED CHRM2 EXPRESSION AND AUGMENTED MUSCARINE'S ANALGESIC EFFECT ON NEUROPATHIC PAIN AND FULLY REVERSED THE NERVE INJURY-INDUCED REDUCTION IN THE INHIBITORY EFFECT OF MUSCARINE ON GLUTAMATERGIC INPUT TO SPINAL DORSAL HORN NEURONS. OUR FINDINGS INDICATE THAT NERVE INJURY-INDUCED REST UP-REGULATION IN DRG NEURONS PLAYS AN IMPORTANT ROLE IN THE ACUTE-TO-CHRONIC PAIN TRANSITION AND IS ESSENTIAL FOR THE TRANSCRIPTIONAL REPRESSION OF CHRM2 IN NEUROPATHIC PAIN. 2018 17 4919 25 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 18 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 19 6767 24 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 20 2407 25 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