1   687 144 BRAINSTEM BRAIN-DERIVED NEUROTROPHIC FACTOR SIGNALING IS REQUIRED FOR HISTONE DEACETYLASE INHIBITOR-INDUCED PAIN RELIEF. OUR PREVIOUS STUDY DEMONSTRATED THAT PERSISTENT PAIN CAN EPIGENETICALLY SUPPRESS THE TRANSCRIPTION OF GAD2 [ENCODING GLUTAMIC ACID DECARBOXYLASE 65 (GAD65)] AND CONSEQUENTLY IMPAIR THE INHIBITORY FUNCTION OF GABAERGIC SYNAPSES IN CENTRAL PAIN-MODULATING NEURONS. THIS CONTRIBUTES TO THE DEVELOPMENT OF PERSISTENT PAIN SENSITIZATION. HISTONE DEACETYLASE (HDAC) INHIBITORS INCREASED GAD65 ACTIVITY CONSIDERABLY, RESTORED GABA SYNAPTIC FUNCTION, AND RENDERED SENSITIZED PAIN BEHAVIOR LESS PRONOUNCED. HOWEVER, THE MOLECULAR MECHANISMS BY WHICH HDAC REGULATES GABAERGIC TRANSMISSION THROUGH GAD65 UNDER PAIN CONDITIONS ARE UNKNOWN. THIS WORK SHOWED THAT HDAC INHIBITOR-INDUCED INCREASES IN COLOCALIZATION OF GAD65 AND SYNAPTIC PROTEIN SYNAPSIN I ON THE PRESYNAPTIC AXON TERMINALS OF THE NUCLEUS RAPHE MAGNUS (NRM) WERE BLOCKED BY A TRKB RECEPTOR ANTAGONIST K252A [(9S,10R,12R)-2,3,9,10,11,12-HEXAHYDRO-10-HYDROXY-9-METHYL-1-OXO-9,12-EPOXY-1H-DIINDOLO[1,2,3-FG:3',2',1'-KL]PYRROLO[3,4-I][1,6]BENZODIAZOCINE-10-CARBOXYLIC ACID METHYL ESTER], INDICATING THAT BDNF-TRKB SIGNALING MAY BE REQUIRED IN GAD65 MODULATION OF GABA SYNAPTIC FUNCTION. AT THE BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) PROMOTER, HDAC INHIBITORS INDUCED SIGNIFICANT INCREASES IN H3 HYPERACETYLATION, CONSISTENT WITH THE INCREASE IN BDNF MRNA AND TOTAL PROTEINS. ALTHOUGH EXOGENOUS BDNF FACILITATED GABA MINIATURE INHIBITORY POSTSYNAPTIC CURRENTS AND GAD65 ACCUMULATION IN NRM NEURONAL SYNAPSES IN NORMAL RATS, IT FAILED TO DO SO IN ANIMALS SUBJECTED TO PERSISTENT INFLAMMATION. IN ADDITION, BLOCKADE OF THE TRKB RECEPTOR WITH K252A HAS NO EFFECT ON MINIATURE INHIBITORY POSTSYNAPTIC CURRENTS AND SYNAPTIC GAD65 ACCUMULATION UNDER NORMAL CONDITIONS. IN ADDITION, THE ANALGESIC EFFECTS OF HDAC INHIBITORS ON BEHAVIOR WERE BLOCKED BY NRM INFUSION OF K252A. THESE FINDINGS SUGGEST THAT BDNF-TRKB SIGNALING IS REQUIRED FOR DRUGS THAT REVERSE THE EPIGENETIC EFFECTS OF CHRONIC PAIN AT THE GENE LEVEL, SUCH AS HDAC INHIBITORS.	2015	
                                                                                                                                                                                                                                                                                                                                                                                                                                                     
2  3332  60 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	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
3  2448  53 EPIGENETIC SUPPRESSION OF GAD65 EXPRESSION MEDIATES PERSISTENT PAIN. CHRONIC PAIN IS A COMMON NEUROLOGICAL DISEASE INVOLVING LASTING, MULTIFACETED MALADAPTATIONS RANGING FROM GENE MODULATION TO SYNAPTIC DYSFUNCTION AND EMOTIONAL DISORDERS. SUSTAINED PATHOLOGICAL STIMULI IN MANY DISEASES ALTER THE OUTPUT ACTIVITIES OF CERTAIN GENES THROUGH EPIGENETIC MODIFICATIONS, BUT IT IS UNCLEAR HOW EPIGENETIC MECHANISMS OPERATE IN THE DEVELOPMENT OF CHRONIC PAIN. WE SHOW HERE THAT IN THE RAT BRAINSTEM NUCLEUS RAPHE MAGNUS, WHICH IS IMPORTANT FOR CENTRAL MECHANISMS OF CHRONIC PAIN, PERSISTENT INFLAMMATORY AND NEUROPATHIC PAIN EPIGENETICALLY SUPPRESSES GAD2 (ENCODING GLUTAMIC ACID DECARBOXYLASE 65 (GAD65)) TRANSCRIPTION THROUGH HISTONE DEACETYLASE (HDAC)-MEDIATED HISTONE HYPOACETYLATION, RESULTING IN IMPAIRED GAMMA-AMINOBUTYRIC ACID (GABA) SYNAPTIC INHIBITION. GAD2 KNOCKOUT MICE SHOWED SENSITIZED PAIN BEHAVIOR AND IMPAIRED GABA SYNAPTIC FUNCTION IN THEIR BRAINSTEM NEURONS. IN WILD-TYPE BUT NOT GAD2 KNOCKOUT MICE, HDAC INHIBITORS STRONGLY INCREASED GAD65 ACTIVITY, RESTORED GABA SYNAPTIC FUNCTION AND RELIEVED SENSITIZED PAIN BEHAVIOR. THESE FINDINGS SUGGEST GAD65 AND HDACS AS POTENTIAL THERAPEUTIC TARGETS IN AN EPIGENETIC APPROACH TO THE TREATMENT OF CHRONIC PAIN.	2011	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
4  5018  58 PERSISTENT INFLAMMATION-INDUCED UP-REGULATION OF BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) PROMOTES SYNAPTIC DELIVERY OF ALPHA-AMINO-3-HYDROXY-5-METHYL-4-ISOXAZOLEPROPIONIC ACID RECEPTOR GLUA1 SUBUNITS IN DESCENDING PAIN MODULATORY CIRCUITS. THE ENHANCED AMPA RECEPTOR PHOSPHORYLATION AT GLUA1 SERINE 831 SITES IN THE CENTRAL PAIN-MODULATING SYSTEM PLAYS A PIVOTAL ROLE IN DESCENDING PAIN FACILITATION AFTER INFLAMMATION, BUT THE UNDERLYING MECHANISMS REMAIN UNCLEAR. WE SHOW HERE THAT, IN THE RAT BRAIN STEM, IN THE NUCLEUS RAPHE MAGNUS, WHICH IS A CRITICAL RELAY IN THE DESCENDING PAIN-MODULATING SYSTEM OF THE BRAIN, PERSISTENT INFLAMMATORY PAIN INDUCED BY COMPLETE FREUND ADJUVANT (CFA) CAN ENHANCE AMPA RECEPTOR-MEDIATED EXCITATORY POSTSYNAPTIC CURRENTS AND THE GLUA2-LACKING AMPA RECEPTOR-MEDIATED RECTIFICATION INDEX. WESTERN BLOT ANALYSIS SHOWED AN INCREASE IN GLUA1 PHOSPHORYLATION AT SER-831 BUT NOT AT SER-845. THIS WAS ACCOMPANIED BY AN INCREASE IN DISTRIBUTION OF THE SYNAPTIC GLUA1 SUBUNIT. IN PARALLEL, THE LEVEL OF HISTONE H3 ACETYLATION AT BDNF GENE PROMOTER REGIONS WAS REDUCED SIGNIFICANTLY 3 DAYS AFTER CFA INJECTION, AS INDICATED BY CHIP ASSAYS. THIS WAS CORRELATED WITH AN INCREASE IN BDNF MRNA LEVELS AND BDNF PROTEIN LEVELS. SEQUESTERING ENDOGENOUS EXTRACELLULAR BDNF WITH TRKB-IGG IN THE NUCLEUS RAPHE MAGNUS DECREASED AMPA RECEPTOR-MEDIATED SYNAPTIC TRANSMISSION AND GLUA1 PHOSPHORYLATION AT SER-831 3 DAYS AFTER CFA INJECTION. UNDER THE SAME CONDITIONS, BLOCKADE OF TRKB RECEPTOR FUNCTIONS, PHOSPHOLIPASE C, OR PKC IMPAIRED GLUA1 PHOSPHORYLATION AT SER-831 AND DECREASED EXCITATORY POSTSYNAPTIC CURRENTS MEDIATED BY GLUA2-LACKING AMPA RECEPTORS. TAKEN TOGETHER, THESE RESULTS SUGGEST THAT EPIGENETIC UP-REGULATION OF BDNF BY PERIPHERAL INFLAMMATION INDUCES GLUR1 PHOSPHORYLATION AT SER-831 SITES THROUGH ACTIVATION OF THE PHOSPHOLIPASE C-PKC SIGNALING CASCADE, LEADING TO THE TRAFFICKING OF GLUA1 TO PAIN-MODULATING NEURONAL SYNAPSES.	2014	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
5  3542  32 IMMUNOHISTOCHEMICAL ANALYSIS OF HISTONE H3 ACETYLATION IN THE TRIGEMINAL ROOT ENTRY ZONE IN AN ANIMAL MODEL OF TRIGEMINAL NEURALGIA. OBJECTIVE: THE TRIGEMINAL ROOT ENTRY ZONE (TREZ) IS A TRANSITIONAL ZONE BETWEEN THE CENTRAL NERVOUS SYSTEM (CNS) AND PERIPHERAL NERVOUS SYSTEM (PNS), ADJACENT TO THE BRAINSTEM. MICROVASCULAR COMPRESSION OF THE TREZ HAS BEEN CONSIDERED TO BE THE PRIMARY ETIOLOGY IN MOST CASES OF TRIGEMINAL NEURALGIA (TN), BUT WHETHER EPIGENETIC REGULATION IS INVOLVED IN THE PATHOGENESIS OF TN IS STILL UNCLEAR. THEREFORE, THIS STUDY WAS DESIGNED TO INVESTIGATE THE EPIGENETIC REGULATION OF HISTONE H3 ACETYLATION IN THE TREZ IN AN ANIMAL MODEL OF TN. METHODS: AN ANIMAL MODEL OF TN WAS ESTABLISHED, AND ADULT MALE SPRAGUE-DAWLEY RATS WERE RANDOMLY ASSIGNED TO A TN GROUP WITH TRIGEMINAL NERVE ROOT COMPRESSION, SHAM OPERATION GROUP, TN+HDACI GROUP (TN PLUS SELECTIVE HISTONE DEACETYLASE INHIBITOR INJECTION INTO THE TREZ), OR TN+VEH GROUP (TN PLUS VEHICLE INJECTION INTO THE TREZ). TO MEASURE THE LENGTH OF THE CENTRAL PORTION OF THE TREZ FROM THE JUNCTION OF THE TRIGEMINAL NERVE ROOT ENTERING THE PONS TO THE INTERFACE OF THE DOME-SHAPED CNS-PNS TRANSITIONAL ZONE, IMMUNOFLUORESCENT STAINING OF GLIA AND GLIAL NUCLEI WAS PERFORMED USING GLIAL FIBRILLARY ACIDIC PROTEIN (GFAP) ANTIBODY AND DAPI, RESPECTIVELY. TO INVESTIGATE THE ACETYLATION OF HISTONE H3 WITHIN THE TREZ IN A TN ANIMAL MODEL GROUP AND A SHAM OPERATION GROUP, LOCALIZATION OF HISTONE H3K9, H3K18, AND H3K27 ACETYLATION WAS EXAMINED VIA IMMUNOHISTOCHEMICAL STAINING METHODS. RESULTS: MEASUREMENTS OF THE CNS-PNS TRANSITIONAL ZONE IN THE TREZ REVEALED THAT THE AVERAGE LENGTH FROM THE JUNCTION OF THE TRIGEMINAL NERVE ROOT CONNECTING THE PONS TO THE GLIAL FRINGE OF THE TREZ IN THE TN GROUP WAS LONGER THAN THAT IN THE SHAM OPERATION GROUP (P < 0.05) AND THAT THE INTERFACE GRADUALLY MIGRATED DISTALLY. CELLS THAT STAINED POSITIVE FOR ACETYLATED HISTONE H3K9, H3K18, AND H3K27 WERE DISTRIBUTED AROUND BOTH SIDES OF THE BORDER OF THE CNS-PNS JUNCTION IN THE TREZ. THE RATIO OF IMMUNOREACTIVE H3K9-, H3K18- AND H3K27-POSITIVE CELLS IN THE TN GROUP WAS OBVIOUSLY HIGHER THAN THAT IN THE SHAM OPERATION GROUP ON POSTOPERATIVE DAYS 7, 14, 21, AND 28 (P < 0.05). CONCLUSIONS: THESE RESULTS SUGGESTED THAT CHRONIC COMPRESSION OF THE TRIGEMINAL NERVE ROOT MAY BE INVOLVED IN THE PATHOGENESIS OF TN IN AN ANIMAL MODEL BY INFLUENCING THE PLASTICITY OF THE CNS-PNS TRANSITIONAL ZONE AND THE LEVEL OF HISTONE ACETYLATION IN THE TREZ.	2018	
                                    
6  2751  36 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   742  42 CANNABINOID CB2 RECEPTORS ARE UPREGULATED VIA BIVALENT HISTONE MODIFICATIONS AND CONTROL PRIMARY AFFERENT INPUT TO THE SPINAL CORD IN NEUROPATHIC PAIN. TYPE-2 CANNABINOID RECEPTORS (CB2, ENCODED BY THE CNR2 GENE) ARE MAINLY EXPRESSED IN IMMUNE CELLS, AND CB2 AGONISTS NORMALLY HAVE NO ANALGESIC EFFECT. HOWEVER, NERVE INJURY UPREGULATES CB2 IN THE DORSAL ROOT GANGLION (DRG), FOLLOWING WHICH CB2 STIMULATION REDUCES NEUROPATHIC PAIN. IT IS UNCLEAR HOW NERVE INJURY INCREASES CB2 EXPRESSION OR HOW CB2 ACTIVITY IS TRANSFORMED IN NEUROPATHIC PAIN. IN THIS STUDY, IMMUNOBLOTTING SHOWED THAT SPINAL NERVE LIGATION (SNL) INDUCED A DELAYED AND SUSTAINED INCREASE IN CB2 EXPRESSION IN THE DRG AND DORSAL SPINAL CORD SYNAPTOSOMES. RNASCOPE IN SITU HYBRIDIZATION ALSO SHOWED THAT SNL SUBSTANTIALLY INCREASED CB2 MRNA LEVELS, MOSTLY IN MEDIUM AND LARGE DRG NEURONS. FURTHERMORE, WE FOUND THAT THE SPECIFIC CB2 AGONIST JWH-133 SIGNIFICANTLY INHIBITS THE AMPLITUDE OF DORSAL ROOT-EVOKED GLUTAMATERGIC EXCITATORY POSTSYNAPTIC CURRENTS IN SPINAL DORSAL HORN NEURONS IN SNL RATS, BUT NOT IN SHAM CONTROL RATS; INTRATHECAL INJECTION OF JWH-133 REVERSED PAIN HYPERSENSITIVITY IN SNL RATS, BUT HAD NO EFFECT IN SHAM CONTROL RATS. IN ADDITION, CHROMATIN IMMUNOPRECIPITATION-QPCR ANALYSIS SHOWED THAT SNL INCREASED ENRICHMENT OF TWO ACTIVATING HISTONE MARKS (H3K4ME3 AND H3K9AC) AND DIMINISHED OCCUPANCY OF TWO REPRESSIVE HISTONE MARKS (H3K9ME2 AND H3K27ME3) AT THE CNR2 PROMOTER IN THE DRG. IN CONTRAST, SNL HAD NO EFFECT ON DNA METHYLATION LEVELS AROUND THE CNR2 PROMOTER. OUR FINDINGS SUGGEST THAT PERIPHERAL NERVE INJURY PROMOTES CB2 EXPRESSION IN PRIMARY SENSORY NEURONS VIA EPIGENETIC BIVALENT HISTONE MODIFICATIONS AND THAT CB2 ACTIVATION REDUCES NEUROPATHIC PAIN BY ATTENUATING NOCICEPTIVE TRANSMISSION FROM PRIMARY AFFERENT NERVES TO THE SPINAL CORD.	2022	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
8  2452  51 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	
                                                                                                                                                                                                                                                                                        
9  4616  39 NERVE INJURY INCREASES BRAIN-DERIVED NEUROTROPHIC FACTOR LEVELS TO SUPPRESS BK CHANNEL ACTIVITY IN PRIMARY SENSORY NEURONS. ABNORMAL HYPEREXCITABILITY OF PRIMARY SENSORY NEURONS CONTRIBUTES TO NEUROPATHIC PAIN DEVELOPMENT AFTER NERVE INJURY. NERVE INJURY PROFOUNDLY REDUCES THE EXPRESSION OF BIG CONDUCTANCE CA(2+) -ACTIVATED K(+) (BK) CHANNELS IN THE DORSAL ROOT GANGLION (DRG). HOWEVER, LITTLE IS KNOWN ABOUT HOW NERVE INJURY AFFECTS BK CHANNEL ACTIVITY IN DRG NEURONS. IN THIS STUDY, WE DETERMINED THE CHANGES IN BK CHANNEL ACTIVITY IN DRG NEURONS IN A RAT MODEL OF NEUROPATHIC PAIN AND THE CONTRIBUTION OF BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) TO REDUCED BK CHANNEL ACTIVITY. THE BK CHANNEL ACTIVITY WAS PRESENT PREDOMINANTLY IN SMALL AND MEDIUM DRG NEURONS, AND LIGATION OF L5 AND L6 SPINAL NERVES PROFOUNDLY DECREASED THE BK CURRENT DENSITY IN THESE NEURONS. BLOCKING BK CHANNELS SIGNIFICANTLY INCREASED NEURONAL EXCITABILITY IN SHAM CONTROL, BUT NOT IN NERVE-INJURED, RATS. THE BDNF CONCENTRATION IN THE DRG WAS SIGNIFICANTLY GREATER IN NERVE-INJURED RATS THAN IN CONTROL RATS. BDNF TREATMENT LARGELY REDUCED BK CURRENTS IN DRG NEURONS IN CONTROL RATS, WHICH WAS BLOCKED BY EITHER ANTI-BDNF ANTIBODY OR K252A, A TRK RECEPTOR INHIBITOR. FURTHERMORE, EITHER ANTI-BDNF ANTIBODY OR K252A REVERSED REDUCTION IN BK CURRENTS IN INJURED DRG NEURONS. BDNF TREATMENT REDUCED THE MRNA LEVELS OF BKALPHA1 SUBUNIT IN DRG NEURONS, AND ANTI-BDNF ANTIBODY ATTENUATED THE REDUCTION IN THE BKALPHA1 MRNA LEVEL IN INJURED DRG NEURONS. THESE FINDINGS SUGGEST THAT NERVE INJURY PRIMARILY DIMINISHES THE BK CHANNEL ACTIVITY IN SMALL AND MEDIUM DRG NEURONS. INCREASED BDNF LEVELS CONTRIBUTE TO REDUCED BK CHANNEL ACTIVITY IN DRG NEURONS THROUGH EPIGENETIC AND TRANSCRIPTIONAL MECHANISMS IN NEUROPATHIC PAIN.	2012	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
10  5084  34 PIGMENTED EPENDYMOMA, A TUMOR WITH PREDILECTION FOR THE MIDDLE-AGED ADULT: CASE REPORT WITH METHYLATION CLASSIFICATION AND REVIEW OF 16 LITERATURE CASES. EPENDYMOMAS HAVE RARELY BEEN DESCRIBED TO CONTAIN PIGMENT OTHER THAN MELANIN, NEUROMELANIN, LIPOFUSCIN OR A COMBINATION. IN THIS CASE REPORT, WE PRESENT A PIGMENTED EPENDYMOMA IN THE FOURTH VENTRICLE OF AN ADULT PATIENT AND REVIEW 16 ADDITIONAL CASES OF PIGMENTED EPENDYMOMA FROM THE LITERATURE. A 46-YEAR-OLD FEMALE SHOWED UP WITH HEARING LOSS, HEADACHES, AND NAUSEA. MAGNETIC RESONANCE IMAGING REVEALED A 2.5 CM CONTRAST-ENHANCING CYSTIC MASS IN THE FOURTH VENTRICLE, WHICH WAS RESECTED. INTRAOPERATIVELY, THE TUMOR APPEARED GREY-BROWN, CYSTIC, AND WAS ADHERENT TO THE BRAINSTEM. ROUTINE HISTOLOGY REVEALED A TUMOR WITH TRUE ROSETTES, PERIVASCULAR PSEUDOROSETTES AND EPENDYMAL CANALS CONSISTENT WITH EPENDYMOMA, BUT ALSO SHOWED CHRONIC INFLAMMATION AND ABUNDANT DISTENDED PIGMENTED TUMOR CELLS THAT MIMICKED MACROPHAGES IN FROZEN AND PERMANENT SECTIONS. THE PIGMENTED CELLS WERE POSITIVE FOR GFAP AND NEGATIVE FOR CD163 CONSONANT WITH GLIAL TUMOR CELLS. THE PIGMENT WAS NEGATIVE FOR FONTANA-MASSON, POSITIVE FOR PERIODIC-ACID SCHIFF AND AUTOFLUORESCENT, WHICH COINCIDE WITH CHARACTERISTICS OF LIPOFUSCIN. PROLIFERATION INDICES WERE LOW AND H3K27ME3 SHOWED PARTIAL LOSS. H3K27ME 3 IS AN EPIGENETIC MODIFICATION TO THE DNA PACKAGING PROTEIN HISTONE H3 THAT INDICATES THE TRI-METHYLATION OF LYSINE 27 ON HISTONE H3 PROTEIN. THIS METHYLATION CLASSIFICATION WAS COMPATIBLE WITH A POSTERIOR FOSSA GROUP B EPENDYMOMA (EPN_PFB). THE PATIENT WAS CLINICALLY WELL WITHOUT RECURRENCE AT THREE-MONTH POST-OPERATIVE FOLLOW-UP APPOINTMENT. OUR ANALYSIS OF ALL 17 CASES, INCLUDING THE ONE PRESENTED, SHOWS THAT PIGMENTED EPENDYMOMAS ARE MOST COMMON IN THE MIDDLE-AGED WITH A MEDIAN AGE OF 42 YEARS AND MOST HAVE A FAVORABLE OUTCOME. HOWEVER, ONE PATIENT THAT ALSO DEVELOPED SECONDARY LEPTOMENINGEAL MELANIN ACCUMULATIONS DIED. MOST (58.8%) ARISE IN THE 4TH VENTRICLE, WHILE SPINAL CORD (17.6%) AND SUPRATENTORIAL LOCATIONS (17.6%) WERE LESS COMMON. THE AGE OF PRESENTATION AND GENERALLY GOOD PROGNOSIS RAISE THE QUESTION OF WHETHER MOST OTHER POSTERIOR FOSSA PIGMENTED EPENDYMOMAS MAY ALSO FALL INTO THE EPN_PFB GROUP, BUT ADDITIONAL STUDY IS REQUIRED TO ADDRESS THAT QUESTION.	2022	
                                                                                                                                                                                                                              
11  3196  26 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	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
12    69  50 A MEDIAL PREFRONTAL CORTEX-NUCLEUS ACUMENS CORTICOTROPIN-RELEASING FACTOR CIRCUITRY FOR NEUROPATHIC PAIN-INCREASED SUSCEPTIBILITY TO OPIOID REWARD. RECENT STUDIES HAVE SHOWN THAT PERSISTENT PAIN FACILITATES THE RESPONSE TO MORPHINE REWARD. HOWEVER, THE CIRCUIT MECHANISM UNDERLYING THIS PROCESS REMAINS AMBIGUOUS. IN THIS STUDY, USING CHRONIC CONSTRICTION INJURY (CCI) OF THE SCIATIC NERVE IN MICE, WE FOUND THAT PERSISTENT NEUROPATHIC PAIN REDUCED THE MINIMUM NUMBER OF MORPHINE CONDITIONING SESSIONS REQUIRED TO INDUCE CONDITIONED PLACE PREFERENCE (CPP) BEHAVIOR. THIS DOSE OF MORPHINE HAD NO EFFECT ON THE PAIN THRESHOLD. IN THE MEDIAL PREFRONTAL CORTEX (MPFC), WHICH IS INVOLVED IN BOTH PAIN AND EMOTION PROCESSING, CORTICOTROPIN-RELEASING FACTOR (CRF) EXPRESSING NEURONAL ACTIVITY WAS INCREASED IN CCI MICE. CHEMOGENETIC INHIBITION OF MPFC CRF NEURONS REVERSED CCI-INDUCED MORPHINE CPP FACILITATION. FURTHERMORE, THE NUCLEUS ACUMENS (NAC) RECEIVED MPFC CRF FUNCTIONAL PROJECTIONS THAT EXERTED EXCITATORY EFFECTS ON NAC NEURONS. OPTOGENETIC INHIBITION OF MPCF NEURONAL TERMINALS OR LOCAL INFUSION OF THE CRF RECEPTOR 1 (CRFR1) ANTAGONIST IN THE NAC RESTORED THE EFFECTS OF NEUROPATHIC PAIN ON MORPHINE-INDUCED CPP BEHAVIOR, BUT NOT IN NORMAL MICE. ON A MOLECULAR LEVEL, IN CCI MICE, CRFR1 PROTEIN EXPRESSION WAS INCREASED IN THE NAC BY A HISTONE DIMETHYLTRANSFERASE G9A-MEDIATED EPIGENETIC MECHANISM. LOCAL G9A KNOCKDOWN INCREASED THE EXPRESSION OF CRFR1 AND MIMICKED CCI-INDUCED HYPERSENSITIVITY TO ACQUIRING MORPHINE CPP. TAKEN TOGETHER, THESE FINDINGS DEMONSTRATE A PREVIOUSLY UNKNOWN AND SPECIFIC MPFC CRF ENGAGEMENT OF NAC NEURONAL CIRCUITS, THE SENSITIZATION OF WHICH FACILITATES BEHAVIORAL RESPONSES TO MORPHINE REWARD IN NEUROPATHIC PAIN STATES VIA CRFR1S.	2018	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
13  4669  35 NEW INSIGHTS INTO PATHOPHYSIOLOGY OF VESTIBULAR MIGRAINE. VESTIBULAR MIGRAINE (VM) IS A COMMON DISORDER IN WHICH GENETIC, EPIGENETIC, AND ENVIRONMENTAL FACTORS PROBABLY CONTRIBUTE TO ITS DEVELOPMENT. THE PATHOPHYSIOLOGY OF VM IS UNKNOWN; NEVERTHELESS IN THE LAST FEW YEARS, SEVERAL STUDIES ARE CONTRIBUTING TO UNDERSTAND THE NEUROPHYSIOLOGICAL PATHWAYS INVOLVED IN VM. THE CURRENT HYPOTHESES ARE MOSTLY BASED ON THE KNOWLEDGE OF MIGRAINE ITSELF. THE EVIDENCE OF TRIGEMINAL INNERVATION OF THE LABYRINTH VESSELS AND THE LOCALIZATION OF VASOACTIVE NEUROPEPTIDES IN THE PERIVASCULAR AFFERENT TERMINALS OF THESE TRIGEMINAL FIBERS SUPPORT THE INVOLVEMENT OF THE TRIGEMINO-VASCULAR SYSTEM. THE NEUROGENIC INFLAMMATION TRIGGERED BY ACTIVATION OF THE TRIGEMINAL-VESTIBULOCOCHLEAR REFLEX, WITH THE SUBSEQUENT INNER EAR PLASMA PROTEIN EXTRAVASATION AND THE RELEASE OF INFLAMMATORY MEDIATORS, CAN CONTRIBUTE TO A SUSTAINED ACTIVATION AND SENSITIZATION OF THE TRIGEMINAL PRIMARY AFFERENT NEURONS EXPLAINING VM SYMPTOMS. THE RECIPROCAL CONNECTIONS BETWEEN BRAINSTEM VESTIBULAR NUCLEI AND THE STRUCTURES THAT MODULATE TRIGEMINAL NOCICEPTIVE INPUTS (ROSTRAL VENTROMEDIAL MEDULLA, VENTROLATERAL PERIAQUEDUCTAL GRAY, LOCUS COERULEUS, AND NUCLEUS RAPHE MAGNUS) ARE CRITICAL TO UNDERSTAND THE PATHOPHYSIOLOGY OF VM. ALTHOUGH CORTICAL SPREADING DEPRESSION CAN AFFECT CORTICAL AREAS INVOLVED IN PROCESSING VESTIBULAR INFORMATION, FUNCTIONAL NEUROIMAGING TECHNIQUES SUGGEST A DYSMODULATION IN THE MULTIMODAL SENSORY INTEGRATION AND PROCESSING OF VESTIBULAR AND NOCICEPTIVE INFORMATION, RESULTING FROM A VESTIBULO-THALAMO-CORTICAL DYSFUNCTION, AS THE PATHOGENIC MECHANISM UNDERLYING VM. THE ELEVATED PREVALENCE OF VM SUGGESTS THAT MULTIPLE FUNCTIONAL VARIANTS MAY CONFER A GENETIC SUSCEPTIBILITY LEADING TO A DYSREGULATION OF EXCITATORY-INHIBITORY BALANCE IN BRAIN STRUCTURES INVOLVED IN THE PROCESSING OF SENSORY INFORMATION, VESTIBULAR INPUTS, AND PAIN. THE INTERACTIONS AMONG SEVERAL FUNCTIONAL AND STRUCTURAL NEURAL NETWORKS COULD EXPLAIN THE PATHOGENIC MECHANISMS OF VM.	2015	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
14  4615  46 NERVE INJURY DIMINISHES OPIOID ANALGESIA THROUGH LYSINE METHYLTRANSFERASE-MEDIATED TRANSCRIPTIONAL REPRESSION OF MU-OPIOID RECEPTORS IN PRIMARY SENSORY NEURONS. THE MU-OPIOID RECEPTOR (MOR, ENCODED BY OPRM1) AGONISTS ARE THE MAINSTAY ANALGESICS FOR TREATING MODERATE TO SEVERE PAIN. NERVE INJURY CAUSES DOWN-REGULATION OF MORS IN THE DORSAL ROOT GANGLION (DRG) AND DIMINISHES THE OPIOID EFFECT ON NEUROPATHIC PAIN. HOWEVER, THE EPIGENETIC MECHANISMS UNDERLYING THE DIMINISHED MOR EXPRESSION CAUSED BY NERVE INJURY ARE NOT CLEAR. G9A (ENCODED BY EHMT2), A HISTONE 3 AT LYSINE 9 METHYLTRANSFERASE, IS A KEY CHROMATIN REGULATOR RESPONSIBLE FOR GENE SILENCING. IN THIS STUDY, WE DETERMINED THE ROLE OF G9A IN DIMINISHED MOR EXPRESSION AND OPIOID ANALGESIC EFFECTS IN ANIMAL MODELS OF NEUROPATHIC PAIN. WE FOUND THAT NERVE INJURY IN RATS INDUCED A LONG-LASTING REDUCTION IN THE EXPRESSION LEVEL OF MORS IN THE DRG BUT NOT IN THE SPINAL CORD. NERVE INJURY CONSISTENTLY INCREASED THE ENRICHMENT OF THE G9A PRODUCT HISTONE 3 AT LYSINE 9 DIMETHYLATION IN THE PROMOTER OF OPRM1 IN THE DRG. G9A INHIBITION OR SIRNA KNOCKDOWN FULLY REVERSED MOR EXPRESSION IN THE INJURED DRG AND POTENTIATED THE MORPHINE EFFECT ON PAIN HYPERSENSITIVITY INDUCED BY NERVE INJURY. IN MICE LACKING EHMT2 IN DRG NEURONS, NERVE INJURY FAILED TO REDUCE THE EXPRESSION LEVEL OF MORS AND THE MORPHINE EFFECT. IN ADDITION, G9A INHIBITION OR EHMT2 KNOCKOUT IN DRG NEURONS NORMALIZED NERVE INJURY-INDUCED REDUCTION IN THE INHIBITORY EFFECT OF THE OPIOID ON SYNAPTIC GLUTAMATE RELEASE FROM PRIMARY AFFERENT NERVES. OUR FINDINGS INDICATE THAT G9A CONTRIBUTES CRITICALLY TO TRANSCRIPTIONAL REPRESSION OF MORS IN PRIMARY SENSORY NEURONS IN NEUROPATHIC PAIN. G9A INHIBITORS MAY BE USED TO ENHANCE THE OPIOID ANALGESIC EFFECT IN THE TREATMENT OF CHRONIC NEUROPATHIC PAIN.	2016	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
15  2482  43 EPIGENETIC UPREGULATION OF METABOTROPIC GLUTAMATE RECEPTOR 2 IN THE SPINAL CORD ATTENUATES OESTROGEN-INDUCED VISCERAL HYPERSENSITIVITY. OBJECTIVE: EPIGENETIC MECHANISMS ARE POTENTIAL TARGETS TO RELIEVE SOMATIC PAIN. HOWEVER, LITTLE IS KNOWN WHETHER EPIGENETIC REGULATION INTERFERES WITH VISCERAL PAIN. PREVIOUS STUDIES SHOW THAT OESTROGEN FACILITATES VISCERAL PAIN. THIS STUDY AIMED TO DETERMINE WHETHER HISTONE HYPERACETYLATION IN THE SPINAL CORD COULD ATTENUATE OESTROGEN-FACILITATED VISCERAL PAIN. DESIGN: THE EFFECT OF THE HISTONE DEACETYLASE INHIBITOR SUBEROYLANILIDE HYDROXAMIC ACID (SAHA) ON THE MAGNITUDE OF THE VISCEROMOTOR RESPONSE (VMR) TO COLORECTAL DISTENTION WAS EXAMINED IN OVARIECTOMISED RATS WITH/WITHOUT OESTROGEN REPLACEMENT. AN ADDITIONAL INTERACTION WITH THE METABOTROPIC GLUTAMATE RECEPTOR 2/3 (MGLUR2/3) ANTAGONIST LY341495 WAS TESTED. THE LEVELS OF ACETYLATED HISTONE AND MGLUR2 MRNA AND PROTEIN WERE ANALYSED. THE BINDING OF ACETYLATED H3 AND OESTROGEN RECEPTOR ALPHA (ERALPHA) TO THE GRM2 PROMOTER WAS MEASURED BY CHROMATIN IMMUNOPRECIPITATION COUPLED WITH QPCR. RESULTS: IN OVARIECTOMISED RATS, 17BETA-ESTRADIOL (E2), BUT NOT SAFFLOWER OIL, INCREASED THE MAGNITUDE OF THE VMR TO COLORECTAL DISTENTION. SAHA ATTENUATED THE E2-FACILITATED VMR, BUT HAD NO EFFECT IN SAFFLOWER OIL-TREATED RATS. SUBSEQUENT SPINAL ADMINISTRATION OF LY341495 REVERSED THE ANTINOCICEPTIVE EFFECT OF SAHA IN E2 RATS. IN ADDITION, SAHA INCREASED MGLUR2 MRNA AND PROTEIN IN THE SPINAL DORSAL HORN FOLLOWING E2, BUT NOT VEHICLE, TREATMENT. IN CONTRAST, NEITHER E2 NOR SAHA ALONE ALTERED MGLUR2 MRNA. SAHA INCREASED BINDING OF H3K9AC AND ERALPHA TO THE SAME REGIONS OF THE GRM2 PROMOTER IN E2-SAHA-TREATED ANIMALS. CONCLUSIONS: HISTONE HYPERACETYLATION IN THE SPINAL CORD ATTENUATES THE PRONOCICEPTIVE EFFECTS OF OESTROGEN ON VISCERAL SENSITIVITY, SUGGESTING THAT EPIGENETIC REGULATION MAY BE A POTENTIAL APPROACH TO RELIEVE VISCERAL PAIN.	2015	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
16  1120  39 COMPARISON OF DIFFERENT HISTONE DEACETYLASE INHIBITORS IN ATTENUATING INFLAMMATORY PAIN IN RATS. HISTONE DEACETYLASE INHIBITORS (HDACIS), WHICH INTERFERE WITH THE EPIGENETIC PROCESS OF HISTONE ACETYLATION, HAVE SHOWN ANALGESIC EFFECTS IN ANIMAL MODELS OF PERSISTENT PAIN. THE HDAC FAMILY COMPRISES 18 GENES; HOWEVER, THE DIFFERENT EFFECTS OF DISTINCT CLASSES OF HDACIS ON PAIN RELIEF REMAIN UNCLEAR. THE AIM OF THIS STUDY WAS TO DETERMINE THE EFFICACY OF THESE HDACIS ON ATTENUATING THERMAL HYPERALGESIA IN PERSISTENT INFLAMMATORY PAIN. PERSISTENT INFLAMMATORY PAIN WAS INDUCED BY INJECTING COMPLETE FREUND'S ADJUVANT (CFA) INTO THE LEFT HIND PAW OF RATS. THEN, HDACIS TARGETING CLASS I (ENTINOSTAT (MS-275)) AND CLASS IIA (SODIUM BUTYRATE, VALPROIC ACID (VPA), AND 4-PHENYLBUTYRIC ACID (4-PBA)), OR CLASS II (SUBEROYLANILIDE HYDOXAMIC ACID (SAHA), TRICHOSTATIN A (TSA), AND DACINOSTAT (LAQ824)) WERE ADMINISTERED INTRAPERITONEALLY ONCE DAILY FOR 3 OR 4 DAYS. WE FOUND THAT THE INJECTION OF SAHA ONCE A DAY FOR 3 DAYS SIGNIFICANTLY ATTENUATED CFA-INDUCED THERMAL HYPERALGESIA FROM DAY 4 AND LASTED 7 DAYS. IN COMPARISON WITH SAHA, SUPPRESSION OF HYPERALGESIA BY 4-PBA PEAKED ON DAY 2, WHEREAS THAT BY MS-275 OCCURRED ON DAYS 5 AND 6. FATIGUE WAS A SERIOUS SIDE EFFECT SEEN WITH MS-275. THESE FINDINGS WILL BE BENEFICIAL FOR OPTIMIZING THE SELECTION OF SPECIFIC HDACIS IN MEDICAL FIELDS SUCH AS PAIN MEDICINE AND NEUROPSYCHIATRY.	2019	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
17  2745  37 EXPRESS: HISTONE HYPERACETYLATION MODULATES SPINAL TYPE II METABOTROPIC GLUTAMATE RECEPTOR ALLEVIATING STRESS-INDUCED VISCERAL HYPERSENSITIVITY IN FEMALE RATS. STRESS IS OFTEN A TRIGGER TO EXACERBATE CHRONIC PAIN INCLUDING VISCERAL HYPERSENSITIVITY ASSOCIATED WITH IRRITABLE BOWEL SYNDROME, A FEMALE PREDOMINANT FUNCTIONAL BOWEL DISORDER. EPIGENETIC MECHANISMS THAT MEDIATE STRESS RESPONSES ARE A POTENTIAL TARGET TO INTERFERE WITH VISCERAL PAIN. THE PURPOSE OF THIS STUDY WAS TO EXAMINE THE EFFECT OF A HISTONE DEACETYLASE INHIBITOR, SUBEROYLANILIDE HYDROXAMIC ACID, ON VISCERAL HYPERSENSITIVITY INDUCED BY A SUBCHRONIC STRESSOR IN FEMALE RATS AND TO INVESTIGATE THE INVOLVEMENT OF SPINAL GLUTAMATE RECEPTORS. THREE DAILY SESSIONS OF FORCED SWIM INDUCED VISCERAL HYPERSENSITIVITY. INTRATHECAL SUBEROYLANILIDE HYDROXAMIC ACID PREVENTED OR REVERSED THE STRESS-INDUCED VISCERAL HYPERSENSITIVITY, INCREASED SPINAL HISTONE 3 ACETYLATION AND INCREASED MGLUR2 AND MGLUR3 EXPRESSION. CHROMATIN IMMUNOPRECIPITATION (CHIP) ANALYSIS REVEALED ENRICHMENT OF H3K9AC AND H3K18AC AT SEVERAL PROMOTER GRM2 AND GRM3 REGIONS. THE MGLUR2/3 ANTAGONIST LY341495 REVERSED THE INHIBITORY EFFECT OF SUBEROYLANILIDE HYDROXAMIC ACID ON THE STRESS-INDUCED VISCERAL HYPERSENSITIVITY. IN SURPRISING CONTRAST, STRESS AND/OR SUBEROYLANILIDE HYDROXAMIC ACID HAD NO EFFECT ON SPINAL NMDA RECEPTOR EXPRESSION OR FUNCTION. THESE DATA REVEAL HISTONE MODIFICATION MODULATES MGLUR2/3 EXPRESSION IN THE SPINAL CORD TO ATTENUATE STRESSINDUCED VISCERAL HYPERSENSITIVITY. HDAC INHIBITORS MAY PROVIDE A POTENTIAL APPROACH TO RELIEVE VISCERAL HYPERSENSITIVITY ASSOCIATED WITH IRRITABLE BOWEL SYNDROME.	2016	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
18  2363  40 EPIGENETIC REGULATION OF SPINAL CORD GENE EXPRESSION CONTRIBUTES TO ENHANCED POSTOPERATIVE PAIN AND ANALGESIC TOLERANCE SUBSEQUENT TO CONTINUOUS OPIOID EXPOSURE. BACKGROUND: OPIOIDS HAVE BECOME THE MAINSTAY FOR TREATMENT OF MODERATE TO SEVERE PAIN AND ARE COMMONLY USED TO TREAT SURGICAL PAIN. WHILE OPIOID ADMINISTRATION HAS BEEN SHOWN TO CAUSE OPIOID-INDUCED HYPERALGESIA AND TOLERANCE, INTERACTIONS BETWEEN OPIOID ADMINISTRATION AND SURGERY WITH RESPECT TO THESE PROBLEMATIC ADAPTATIONS HAVE SCARCELY BEEN ADDRESSED. ACCUMULATING EVIDENCE SUGGESTS OPIOIDS AND NOCICEPTIVE SIGNALING MAY CONVERGE ON EPIGENETIC MECHANISMS IN SPINAL CORD TO ENHANCE OR PROLONG NEUROPLASTIC CHANGES. EPIGENETIC REGULATION OF BDNF (BRAIN-DERIVED NEUROTROPHIC FACTOR) AND PDYN (PRODYNORPHIN) GENES MAY BE INVOLVED. RESULTS: FOUR DAYS OF ASCENDING DOSES OF MORPHINE TREATMENT CAUSED OPIOID-INDUCED HYPERALGESIA AND REDUCED OPIOID ANALGESIC EFFICACY IN MICE. BOTH OPIOID-INDUCED HYPERALGESIA AND THE REDUCED OPIOID ANALGESIC EFFICACY WERE ENHANCED IN MICE THAT RECEIVED HINDPAW INCISIONS. THE EXPRESSION OF BDNF AND PDYN (QPCR) WAS INCREASED AFTER MORPHINE TREATMENT AND INCISION. CHROMATIN IMMUNOPRECIPITATION ASSAYS DEMONSTRATED THAT THE PDYN AND BDNF PROMOTERS WERE MORE STRONGLY ASSOCIATED WITH ACETYLATED H3K9 AFTER MORPHINE PLUS INCISION THAN IN THE MORPHINE OR INCISION ALONE GROUPS. SELECTIVE TROPOMYOSIN-RELATED KINASE B (ANA-12) AND KAPPA-OPIOID RECEPTOR (NOR-BINALTORPHIMINE) ANTAGONISTS WERE ADMINISTERED INTRATHECALLY, BOTH REDUCED HYPERALGESIA ONE OR THREE DAYS AFTER SURGERY. ADMINISTRATION OF ANA-12 OR NOR-BINALTORPHIMINE ATTENUATED THE DECREASED MORPHINE ANALGESIC EFFICACY ON DAY 1, BUT ONLY NOR-BINALTORPHIMINE WAS EFFECTIVE ON DAY 3 AFTER INCISION IN OPIOID-EXPOSED GROUP. COADMINISTRATION OF HISTONE ACETYLTRANSFERASE INHIBITOR ANACARDIC ACID DAILY WITH MORPHINE BLOCKED THE DEVELOPMENT OF OPIOID-INDUCED HYPERALGESIA AND ATTENUATED INCISION-ENHANCED HYPERALGESIA IN MORPHINE-TREATED MICE. ANACARDIC ACID HAD SIMILAR EFFECTS ON ANALGESIC TOLERANCE, SHOWING THE INVOLVEMENT OF HISTONE ACETYLATION IN THE INTERACTIONS DETECTED. CONCLUSIONS: SPINAL EPIGENETIC CHANGES INVOLVING BDNF AND PDYN MAY CONTRIBUTE TO THE ENHANCED POSTOPERATIVE NOCICEPTIVE SENSITIZATION AND ANALGESIC TOLERANCE OBSERVED AFTER CONTINUOUS OPIOID EXPOSURE. TREATMENTS BLOCKING THE EPIGENETICALLY MEDIATED UP-REGULATION OF THESE GENES OR ADMINISTRATION OF TRKB OR KAPPA-OPIOID RECEPTOR ANTAGONISTS MAY IMPROVE THE CLINICAL UTILITY OF OPIOIDS, PARTICULARLY AFTER SURGERY.	2016	

19  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	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
20  5328  45 PULSED RADIOFREQUENCY ATTENUATES COMPLETE FREUND'S ADJUVANT-INDUCED EPIGENETIC SUPPRESSION OF POTASSIUM CHLORIDE COTRANSPORTER 2 EXPRESSION. BACKGROUND: PULSED RADIOFREQUENCY (PRF) TREATMENT OFFERS PAIN RELIEF FOR PATIENTS SUFFERING FROM CHRONIC PAIN WHO DO NOT RESPOND WELL TO CONVENTIONAL TREATMENTS. WE TESTED WHETHER PRF TREATMENT ATTENUATED COMPLETE FREUND'S ADJUVANT (CFA)-INDUCED INFLAMMATORY PAIN. EPIGENETIC MODIFICATION OF POTASSIUM-CHLORIDE COTRANSPORTER 2 (KCC2) GENE EXPRESSION WAS EXAMINED TO ELUCIDATE THE POTENTIAL CONTRIBUTING MECHANISM. METHODS: MALE SPRAGUE-DAWLEY RATS WERE INJECTED WITH CFA INTO THE PLANTAR SURFACE OF THE LEFT HIND PAW TO INDUCE INFLAMMATION. PRF (20 MINUTES OF 500-KHZ RF PULSES, DELIVERED AT A RATE OF 2 HZ, MAXIMUM TEMPERATURE 42 MASCULINEC) WAS DELIVERED TO THE L5 AND L6 ANTERIOR PRIMARY RAMUS JUST DISTAL TO THE INTERVERTEBRAL FORAMEN OF ADULT CFA OR SALINE RATS. THE HIND PAW WITHDRAWAL THRESHOLD TO VON FREY FILAMENT STIMULI AND WITHDRAWAL LATENCY TO RADIANT HEAT WERE DETERMINED BEFORE AND AFTER CFA. ACETYL-HISTONE H3 AND H4 WAS DETERMINED BY CHROMATIN IMMUNOPRECIPITATION IN SPINAL DORSAL HORN. KCC2 EXPRESSION WAS DETERMINED BY WESTERN BLOT. INHIBITORY SYNAPTIC FUNCTION WAS EVALUATED BY PATCH CLAMP IN LAMINA II NEURONS. RESULTS: KCC2 GENE EXPRESSION WAS SUPPRESSED THROUGH HISTONE HYPOACETYLATION, RESULTING IN DECREASED EFFICACY OF GABAERGIC SIGNALING IN CFA RATS. PRF INCREASED HISTONE ACETYLATION AND KCC2 EXPRESSION, PARTIALLY RESTORED THE GABA SYNAPTIC FUNCTION, AND RELIEVED SENSITIZED PAIN BEHAVIOR. CONCLUSION: THESE FINDINGS SUGGEST THAT PRF MIGHT BE AN ALTERNATIVE THERAPY FOR INFLAMMATORY PAIN. ONE OF THE UNDERLYING MECHANISMS IS THROUGH MODIFICATION OF KCC2, WHICH IS AN IMPORTANT DETERMINANT FOR THE EFFICACY OF INHIBITORY NEUROTRANSMISSION IN THE SPINAL CORD, AND ITS EXPRESSION LEVELS ARE REGULATED BY HISTONE ACETYLATION EPIGENETICALLY FOLLOWING INFLAMMATION.	2017