1 4708 138 NO ASSOCIATION OF POLYMORPHISMS IN NAV1.7 OR NERVE GROWTH FACTOR RECEPTOR GENES WITH TRIGEMINAL NEURALGIA. OBJECTIVE: TRIGEMINAL NEURALGIA IS DEFINED AS A SUDDEN SEVERE SHOCK-LIKE PAIN WITHIN THE DISTRIBUTION OF THE TRIGEMINAL NERVE. PAIN IS A SUBJECTIVE EXPERIENCE THAT IS INFLUENCED BY GENDER, CULTURE, ENVIRONMENT, PSYCHOLOGICAL TRAITS, AND GENES. SODIUM CHANNELS AND NERVE GROWTH FACTOR PLAY IMPORTANT ROLES IN THE TRANSMISSION OF NOCICEPTIVE SIGNALS AND PAIN. THE AIM OF THIS STUDY WAS TO INVESTIGATE THE OCCURRENCE OF NAV1.7 SODIUM CHANNEL AND NERVE GROWTH FACTOR RECEPTOR TRKA GENE POLYMORPHISMS (SCN9A/RS6746030 AND NTRK1/RS633, RESPECTIVELY) IN TRIGEMINAL NEURALGIA PATIENTS. METHODS: NINETY-SIX SUBJECTS FROM PAIN SPECIALTY CENTERS IN THE SOUTHEASTERN REGION OF BRAZIL WERE DIVIDED INTO 2 GROUPS: 48 WITH CLASSICAL TRIGEMINAL NEURALGIA DIAGNOSIS AND 48 CONTROLS. PAIN WAS EVALUATED USING THE VISUAL ANALOG SCALE AND MULTIDIMENSIONAL MCGILL PAIN QUESTIONNAIRE. GENOMIC DNA WAS OBTAINED FROM ORAL SWABS IN ALL INDIVIDUALS AND WAS ANALYZED BY REAL-TIME POLYMERASE CHAIN REACTION. RESULTS: NO ASSOCIATION WAS OBSERVED BETWEEN EVALUATED POLYMORPHISMS AND TRIGEMINAL NEURALGIA. FOR ALLELE ANALYSES, PATIENTS AND CONTROLS HAD SIMILAR FREQUENCIES FOR BOTH GENES. GENOTYPE DISTRIBUTION OR ALLELE FREQUENCIES OF POLYMORPHISMS ANALYZED HERE DID NOT CORRELATE TO PAIN SCORES. CONCLUSIONS: ALTHOUGH NO ASSOCIATION OF EVALUATED POLYMORPHISMS AND TRIGEMINAL NEURALGIA DIAGNOSIS OR PAIN SEVERITY WAS OBSERVED, OUR DATA DO NOT EXCLUDE THE POSSIBILITY THAT OTHER GENOTYPES AFFECTING THE EXPRESSION OF NAV1.7 OR TRKA ARE ASSOCIATED WITH THE DISEASE. FURTHER STUDIES SHOULD INVESTIGATE DISTINCT GENETIC POLYMORPHISMS AND EPIGENETIC FACTORS THAT MAY BE IMPORTANT IN EXPRESSION OF THESE MOLECULES. 2019 2 3280 31 HERPES ZOSTER OPHTHALMICUS FOLLOWING ONABOTULINUMTOXINA ADMINISTRATION FOR CHRONIC MIGRAINE: A CASE REPORT AND LITERATURE REVIEW. BACKGROUND: THERE IS A GROWING BODY OF LITERATURE DOCUMENTING LOCAL HERPES ZOSTER OUTBREAK FOLLOWING PROCEDURES. THE MECHANISM UNDERLYING THESE OUTBREAKS REMAINS ELUSIVE. WE PRESENT A CASE OF ZOSTER FOLLOWING ONABOTULINUMTOXINA (BTX) FOR MIGRAINE AND A LITERATURE REVIEW. METHODS: CHART AND LITERATURE REVIEW. CASE: A 72-YEAR-OLD WOMAN WITH CHRONIC MIGRAINE RECEIVED BTX INJECTIONS FOR 3 YEARS WITHOUT INCIDENT. SHE HAD A HISTORY OF THORACIC ZOSTER WITH SUBSEQUENT POST-HERPETIC NEURALGIA. IN AUGUST 2013, 48 HOURS AFTER RECEIVING BTX INJECTIONS, SHE DEVELOPED A PAINFUL RASH IN THE RIGHT V1 DISTRIBUTION CONSISTENT WITH HERPES ZOSTER OPHTHALMICUS. ONE WEEK LATER THE RASH HAD RESOLVED WITHOUT TREATMENT. LITERATURE REVIEW: WE IDENTIFIED 65 (INCLUDING 2 FROM JUEL-JENSON) CASES OF ZOSTER REACTIVATION FOLLOWING MINOR PROCEDURES. THESE CASES TEND TO BE IN YOUNG PATIENTS WITHOUT SPECIFIC RISK FACTORS. OUTBREAKS CHARACTERISTICALLY OCCUR AT THE LEVEL OF EXPOSURE TO LOCAL TRAUMA. DISCUSSION: OUR REVIEW SUGGESTS THAT LOCAL TRAUMA, REGARDLESS OF THE NATURE OF STIMULI, MAY BE SUFFICIENT FOR ZOSTER REACTIVATION. WE HYPOTHESIZE THAT THE STRESSORS IN THESE REPORTED CASES EXERT A LOCAL EPIGENETIC INFLUENCE ON VIRAL TRANSCRIPTION, ALLOWING FOR VIRAL REACTIVATION. CONCLUSION: ZOSTER IS A POTENTIAL COMPLICATION OF BTX ADMINISTRATION FOR CHRONIC MIGRAINE IN ADULTS. PHYSICIAN AWARENESS CAN REDUCE THE SIGNIFICANT MORBIDITY ASSOCIATED WITH THIS DISEASE. 2015 3 3542 38 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 4 821 30 CHARACTERIZATION OF ACETYLATION OF HISTONE H3 AT LYSINE 9 IN THE TRIGEMINAL GANGLION OF A RAT TRIGEMINAL NEURALGIA MODEL. TRIGEMINAL NEURALGIA (TN) IS A CHRONIC NEUROPATHIC PAIN DISORDER CHARACTERIZED BY SPONTANEOUS AND ELICITED PAROXYSMS OF ELECTRIC-SHOCK-LIKE OR STABBING PAIN IN A REGION OF THE FACE. THE EPIGENETIC REGULATION OF TN IS STILL OBSCURE. IN CURRENT STUDY, A RAT TN MODEL SUBJECT TO CARBAMAZEPINE (CBZ) TREATMENT WAS ESTABLISHED, AND TRANSCRIPTOME- AND GENOME-SCALE PROFILING OF H3K9AC AND HDAC3 WAS PERFORMED BY RNA-SEQ AND CHIP-SEQ. WE OBSERVED THAT H3K9AC LEVELS IN THE TRIGEMINAL GANGLION WERE LOWER IN THE TN RATS COMPARED WITH THOSE IN THE CONTROL, AND CBZ TREATMENT LED TO RECOVERY OF H3K9AC LEVELS. FURTHER, WE FOUND THAT HDAC3 WAS OVERACTIVATED, WHICH INTERFERED WITH H3K9 ACETYLATION DUE TO HIGHER PHOSPHORYLATION IN TN COMPARED WITH THAT IN THE CONTROL. FINALLY, THE PHOSPHOKINASE LEUCINE-RICH REPEAT KINASE 2 (LRRK2) WAS DEMONSTRATED TO CONTRIBUTE TO HDAC3 ACTIVITY VIA THE MAPK SIGNALING PATHWAY. TAKEN TOGETHER, WE IDENTIFIED A REGULATORY MECHANISM IN WHICH THE PHOSPHATE GROUPS TRANSFERRED FROM ACTIVATED ERK AND LRRK2 TO HDAC3 CAUSED GENOME-SCALE DEACETYLATION AT H3K9 AND RESULTED IN THE SILENCING OF A LARGE NUMBER OF GENES IN TN. THE KINASES OR IMPORTANT ENZYMES WITHIN THIS REGULATORY AXIS MAY REPRESENT IMPORTANT TARGETS FOR TN THERAPY AND PREVENTION. 2022 5 6697 35 VARICELLA-ZOSTER VIRUS HUMAN GANGLIONIC LATENCY: A CURRENT SUMMARY. VARICELLA-ZOSTER VIRUS (VZV) IS A UBIQUITOUS HUMAN HERPES VIRUS TYPICALLY ACQUIRED IN CHILDHOOD WHEN IT CAUSES VARICELLA (CHICKENPOX), FOLLOWING WHICH THE VIRUS ESTABLISHES A LATENT INFECTION IN TRIGEMINAL AND DORSAL ROOT GANGLIA THAT LASTS FOR THE LIFE OF THE INDIVIDUAL. VZV SUBSEQUENTLY REACTIVATES, SPONTANEOUSLY OR AFTER SPECIFIC TRIGGERING FACTORS, TO CAUSE HERPES ZOSTER (SHINGLES), WHICH MAY BE COMPLICATED BY POSTHERPETIC NEURALGIA AND SEVERAL OTHER NEUROLOGICAL COMPLICATIONS INCLUDING VASCULOPATHY. OUR UNDERSTANDING OF VZV LATENCY LAGS BEHIND OUR KNOWLEDGE OF HERPES SIMPLEX VIRUS TYPE 1 (HSV-1) LATENCY PRIMARILY DUE TO THE DIFFICULTY IN PROPAGATING THE VIRUS TO HIGH TITERS IN A CELL-FREE STATE, AND THE LACK OF A SUITABLE SMALL-ANIMAL MODEL FOR STUDYING VIRUS LATENCY AND REACTIVATION. IT IS NOW ESTABLISHED BEYOND DOUBT THAT LATENT VZV IS PREDOMINANTLY LOCATED IN HUMAN GANGLIONIC NEURONS. VIRUS GENE TRANSCRIPTION DURING LATENCY IS EPIGENETICALLY REGULATED, AND APPEARS TO BE RESTRICTED TO EXPRESSION OF AT LEAST SIX GENES, WITH EXPRESSION OF GENE 63 BEING THE HALLMARK OF LATENCY. HOWEVER, VIRAL GENE TRANSCRIPTION MAY BE MORE EXTENSIVE THAN PREVIOUSLY THOUGHT. THERE IS ALSO EVIDENCE FOR SEVERAL VZV GENES BEING EXPRESSED AT THE PROTEIN LEVEL, INCLUDING VZV GENE 63-ENCODED PROTEIN, BUT RECENT EVIDENCE SUGGESTS THAT THIS MAY NOT BE A COMMON EVENT. THE NATURE AND EXTENT OF THE CHRONIC INFLAMMATORY RESPONSE IN LATENTLY INFECTED GANGLIA IS ALSO OF CURRENT INTEREST. THERE REMAIN SEVERAL QUESTIONS CONCERNING THE VZV LATENCY PROCESS THAT STILL NEED TO BE RESOLVED UNAMBIGUOUSLY AND IT IS LIKELY THAT THIS WILL REQUIRE THE USE OF NEWLY DEVELOPED MOLECULAR TECHNOLOGIES, SUCH AS GEXPS MULTIPLEX POLYMERASE CHAIN REACTION (PCR) FOR VIRUS TRANSCRIPTIONAL ANALYSIS AND CHIP-SEQ TO STUDY THE EPIGENETIC OF LATENT VIRUS GENOME ( LIU ET AL, 2010 , BMC BIOL 8: 56). 2010 6 4645 26 NEUROPATHIC PAIN: FROM MECHANISMS TO TREATMENT. NEUROPATHIC PAIN CAUSED BY A LESION OR DISEASE OF THE SOMATOSENSORY NERVOUS SYSTEM IS A COMMON CHRONIC PAIN CONDITION WITH MAJOR IMPACT ON QUALITY OF LIFE. EXAMPLES INCLUDE TRIGEMINAL NEURALGIA, PAINFUL POLYNEUROPATHY, POSTHERPETIC NEURALGIA, AND CENTRAL POSTSTROKE PAIN. MOST PATIENTS COMPLAIN OF AN ONGOING OR INTERMITTENT SPONTANEOUS PAIN OF, FOR EXAMPLE, BURNING, PRICKING, SQUEEZING QUALITY, WHICH MAY BE ACCOMPANIED BY EVOKED PAIN, PARTICULAR TO LIGHT TOUCH AND COLD. ECTOPIC ACTIVITY IN, FOR EXAMPLE, NERVE-END NEUROMA, COMPRESSED NERVES OR NERVE ROOTS, DORSAL ROOT GANGLIA, AND THE THALAMUS MAY IN DIFFERENT CONDITIONS UNDERLIE THE SPONTANEOUS PAIN. EVOKED PAIN MAY SPREAD TO NEIGHBORING AREAS, AND THE UNDERLYING PATHOPHYSIOLOGY INVOLVES PERIPHERAL AND CENTRAL SENSITIZATION. MALADAPTIVE STRUCTURAL CHANGES AND A NUMBER OF CELL-CELL INTERACTIONS AND MOLECULAR SIGNALING UNDERLIE THE SENSITIZATION OF NOCICEPTIVE PATHWAYS. THESE INCLUDE ALTERATION IN ION CHANNELS, ACTIVATION OF IMMUNE CELLS, GLIAL-DERIVED MEDIATORS, AND EPIGENETIC REGULATION. THE MAJOR CLASSES OF THERAPEUTICS INCLUDE DRUGS ACTING ON ALPHA(2)DELTA SUBUNITS OF CALCIUM CHANNELS, SODIUM CHANNELS, AND DESCENDING MODULATORY INHIBITORY PATHWAYS. 2021 7 5355 34 REAC ANTALGIC NEURO MODULATION IN CHRONIC POST HERPETIC NEURALGIA. BACKGROUND: CHRONIC POST-HERPETIC NEURALGIA (CPHN) IS A SYMPTOMATIC CONDITION THAT AFFLICTS ADULTS AND ELDERLY INDIVIDUALS. THE CHRONICITY OF THIS SYMPTOMATOLOGY CAN BE CONDITIONED BY THE EPIGENETIC MODIFICATIONS INDUCED BY THE VIRUS ON THE PROCESSES OF NEUROTRANSMISSION AND SENSITIVITY TO PAIN. THE AIM OF THIS STUDY IS TO INVESTIGATE WHETHER MANIPULATING ENDOGENOUS BIOELECTRICAL ACTIVITY (EBA), RESPONSIBLE FOR NEUROTRANSMISSION PROCESSES AND CONTRIBUTING TO THE INDUCTION OF EPIGENETIC MODIFICATIONS, CAN ALLEVIATE PAIN SYMPTOMS. METHODS: THIS MANIPULATION WAS CARRIED OUT WITH THE ANTALGIC NEUROMODULATION (ANM) TREATMENT OF RADIOELECTRIC ASYMMETRIC CONVEYER (REAC) TECHNOLOGY. PAIN ASSESSMENT BEFORE AND AFTER TREATMENT WAS PERFORMED USING A NUMERICAL ANALOG SCALE (NAS) AND A SIMPLE DESCRIPTIVE SCALE (SDS). RESULTS: THE RESULTS OF THE ANALYSIS SHOWED AN OVER FOUR-POINT DECREASE IN NAS SCALE SCORE AND OVER ONE POINT DECREASE IN SDS SCALE SCORE, WITH A STATISTICAL SIGNIFICANCE FOR BOTH TESTS OF P < 0.005. CONCLUSIONS: THE RESULTS OBTAINED IN THIS STUDY DEMONSTRATE HOW REAC ANM MANIPULATION OF EBA CAN LEAD TO IMPROVEMENT IN EPIGENETICALLY CONDITIONED SYMPTOMS SUCH AS CPHN. THESE RESULTS SHOULD PROMPT FURTHER RESEARCH TO EXPAND KNOWLEDGE AND ENSURE OPTIMIZED THERAPEUTIC OUTCOMES. 2023 8 40 30 A COMPARISON OF HERPES SIMPLEX VIRUS TYPE 1 AND VARICELLA-ZOSTER VIRUS LATENCY AND REACTIVATION. HERPES SIMPLEX VIRUS TYPE 1 (HSV-1; HUMAN HERPESVIRUS 1) AND VARICELLA-ZOSTER VIRUS (VZV; HUMAN HERPESVIRUS 3) ARE HUMAN NEUROTROPIC ALPHAHERPESVIRUSES THAT CAUSE LIFELONG INFECTIONS IN GANGLIA. FOLLOWING PRIMARY INFECTION AND ESTABLISHMENT OF LATENCY, HSV-1 REACTIVATION TYPICALLY RESULTS IN HERPES LABIALIS (COLD SORES), BUT CAN OCCUR FREQUENTLY ELSEWHERE ON THE BODY AT THE SITE OF PRIMARY INFECTION (E.G. WHITLOW), PARTICULARLY AT THE GENITALS. RARELY, HSV-1 REACTIVATION CAN CAUSE ENCEPHALITIS; HOWEVER, A THIRD OF THE CASES OF HSV-1 ENCEPHALITIS ARE ASSOCIATED WITH HSV-1 PRIMARY INFECTION. PRIMARY VZV INFECTION CAUSES VARICELLA (CHICKENPOX) FOLLOWING WHICH LATENT VIRUS MAY REACTIVATE DECADES LATER TO PRODUCE HERPES ZOSTER (SHINGLES), AS WELL AS AN INCREASINGLY RECOGNIZED NUMBER OF SUBACUTE, ACUTE AND CHRONIC NEUROLOGICAL CONDITIONS. FOLLOWING PRIMARY INFECTION, BOTH VIRUSES ESTABLISH A LATENT INFECTION IN NEURONAL CELLS IN HUMAN PERIPHERAL GANGLIA. HOWEVER, THE DETAILED MECHANISMS OF VIRAL LATENCY AND REACTIVATION HAVE YET TO BE UNRAVELLED. IN BOTH CASES LATENT VIRAL DNA EXISTS IN AN 'END-LESS' STATE WHERE THE ENDS OF THE VIRUS GENOME ARE JOINED TO FORM STRUCTURES CONSISTENT WITH UNIT LENGTH EPISOMES AND CONCATEMERS, FROM WHICH VIRAL GENE TRANSCRIPTION IS RESTRICTED. IN LATENTLY INFECTED GANGLIA, THE MOST ABUNDANTLY DETECTED HSV-1 RNAS ARE THE SPLICED PRODUCTS ORIGINATING FROM THE PRIMARY LATENCY ASSOCIATED TRANSCRIPT (LAT). THIS PRIMARY LAT IS AN 8.3 KB UNSTABLE TRANSCRIPT FROM WHICH TWO STABLE (1.5 AND 2.0 KB) INTRONS ARE SPLICED. TRANSCRIPTS MAPPING TO 12 VZV GENES HAVE BEEN DETECTED IN HUMAN GANGLIA REMOVED AT AUTOPSY; HOWEVER, IT IS DIFFICULT TO ASCRIBE THESE AS TRANSCRIPTS PRESENT DURING LATENT INFECTION AS EARLY-STAGE VIRUS REACTIVATION MAY HAVE TRANSPIRED IN THE POST-MORTEM TIME PERIOD IN THE GANGLIA. NONETHELESS, LOW-LEVEL TRANSCRIPTION OF VZV ORF63 HAS BEEN REPEATEDLY DETECTED IN MULTIPLE GANGLIA REMOVED AS CLOSE TO DEATH AS POSSIBLE. THERE IS INCREASING EVIDENCE THAT HSV-1 AND VZV LATENCY IS EPIGENETICALLY REGULATED. IN VITRO MODELS THAT PERMIT PATHWAY ANALYSIS AND IDENTIFICATION OF BOTH EPIGENETIC MODULATIONS AND GLOBAL TRANSCRIPTIONAL MECHANISMS OF HSV-1 AND VZV LATENCY HOLD MUCH PROMISE FOR OUR FUTURE UNDERSTANDING IN THIS COMPLEX AREA. THIS REVIEW SUMMARIZES THE MOLECULAR BIOLOGY OF HSV-1 AND VZV LATENCY AND REACTIVATION, AND ALSO PRESENTS FUTURE DIRECTIONS FOR STUDY. 2015 9 5402 38 REDUCTION OF SIRT1-MEDIATED EPIGENETIC UPREGULATION OF NAV1.7 CONTRIBUTES TO OXALIPLATIN-INDUCED NEUROPATHIC PAIN. BACKGROUND: CLINICALLY, NEUROPATHIC PAIN IS A SEVERE SIDE EFFECT OF OXALIPLATIN CHEMOTHERAPY, WHICH USUALLY LEADS TO DOSE REDUCTION OR CESSATION OF TREATMENT. DUE TO THE UNAWARENESS OF DETAILED MECHANISMS OF OXALIPLATIN-INDUCED NEUROPATHIC PAIN, IT IS DIFFICULT TO DEVELOP AN EFFECTIVE THERAPY AND LIMITS ITS CLINICAL USE. OBJECTIVES: THE AIM OF THE PRESENT STUDY WAS TO IDENTIFY THE ROLE OF SIRTUIN 1 (SIRT1) REDUCTION IN EPIGENETIC REGULATION OF THE EXPRESSION OF VOLTAGE-GATED SODIUM CHANNELS 1.7 (NAV1.7) IN THE DORSAL ROOT GANGLION (DRG) DURING OXALIPLATIN-INDUCED NEUROPATHIC PAIN. STUDY DESIGN: CONTROLLED ANIMAL STUDY. SETTING: UNIVERSITY LABORATORY. METHODS: THE VON FREY TEST WAS PERFORMED TO EVALUATE PAIN BEHAVIOR IN RATS. REAL-TIME QUANTITATIVE POLYMERASE CHAIN REACTION, WESTERN BLOTTING, ELECTROPHYSIOLOGICAL RECORDING, CHROMATIN IMMUNOPRECIPITATION, AND SMALL INTERFERING RNA (SIRNA) WERE USED TO ILLUSTRATE THE MECHANISMS. RESULTS: IN THE PRESENT STUDY, WE FOUND THAT BOTH THE ACTIVITY AND EXPRESSION OF SIRT1 WERE SIGNIFICANTLY DECREASED IN RAT DRG FOLLOWING OXALIPLATIN TREATMENT. THE ACTIVATOR OF SIRT1, RESVERATROL, NOT ONLY INCREASED THE ACTIVITY AND EXPRESSION OF SIRT1, BUT ALSO ATTENUATED THE MECHANICAL ALLODYNIA FOLLOWING OXALIPLATIN TREATMENT. IN ADDITION, LOCAL KNOCKDOWN OF SIRT1 BY INTRATHECAL INJECTION OF SIRT1 SIRNA CAUSED MECHANICAL ALLODYNIA IN NAIVE RATS. BESIDES, OXALIPLATIN TREATMENT ENHANCED THE ACTION POTENTIAL FIRING FREQUENCY OF DRG NEURONS AND THE EXPRESSION OF NAV1.7 IN DRG AND ACTIVATION OF SIRT1 BY RESVERATROL REVERSED THIS EFFECT. FURTHERMORE, BLOCKING NAV1.7 BY PROTX II (A SELECTIVE NAV1.7 CHANNEL BLOCKER) REVERSED OXALIPLATIN-INDUCED MECHANICAL ALLODYNIA. IN ADDITION, HISTONE H3 HYPERACETYLATION AT THE NAV1.7 PROMOTER IN DRG OF RATS FOLLOWING OXALIPLATIN TREATMENT WAS SIGNIFICANTLY SUPPRESSED BY ACTIVATION OF SIRT1 WITH RESVERATROL. MOREOVER, BOTH THE EXPRESSION OF NAV1.7 AND HISTONE H3 ACETYLATION AT THE NAV1.7 PROMOTER WERE UPREGULATED IN THE DRG BY LOCAL KNOCKDOWN OF SIRT1 WITH SIRT1 SIRNA IN NAIVE RATS. LIMITATIONS: MORE UNDERLYING MECHANISM(S) OF SIRT1 REDUCTION AFTER OXALIPLATIN TREATMENT NEEDS TO BE EXPLORED IN FUTURE RESEARCH. CONCLUSIONS: THESE FINDINGS SUGGEST THAT REDUCTION OF SIRT1-MEDIATED EPIGENETIC UPREGULATION OF NAV1.7 IN THE DRG CONTRIBUTES TO THE DEVELOPMENT OF OXALIPLATIN-INDUCED NEUROPATHIC PAIN IN RATS. THE INTRATHECAL DRUG DELIVERY TREATMENT OF ACTIVATING SIRT1 MIGHT BE A NOVEL THERAPEUTIC OPTION FOR OXALIPLATIN-INDUCED NEUROPATHIC PAIN. 2023 10 1612 26 DNA METHYLATION: A TARGET IN NEUROPATHIC PAIN. NEUROPATHIC PAIN (NP), CAUSED BY AN INJURY OR A DISEASE AFFECTING THE SOMATOSENSORY NERVOUS SYSTEM OF THE CENTRAL AND PERIPHERAL NERVOUS SYSTEMS, HAS BECOME A GLOBAL HEALTH CONCERN. RECENT STUDIES HAVE DEMONSTRATED THAT EPIGENETIC MECHANISMS ARE AMONG THOSE THAT UNDERLIE NP; THUS, ELUCIDATING THE MOLECULAR MECHANISM OF DNA METHYLATION IS CRUCIAL TO DISCOVERING NEW THERAPEUTIC METHODS FOR NP. IN THIS REVIEW, WE FIRST BRIEFLY DISCUSS DNA METHYLATION, DEMETHYLATION, AND THE ASSOCIATED KEY ENZYMES, SUCH AS METHYLASES AND DEMETHYLASES. WE THEN DISCUSS THE RELATIONSHIP BETWEEN NP AND DNA METHYLATION, FOCUSING ON DNA METHYLTRANSFERASES INCLUDING METHYL-CPG-BINDING DOMAIN (MBD) FAMILY PROTEINS AND TEN-ELEVEN TRANSLOCATION (TET) ENZYMES. BASED ON EXPERIMENTAL RESULTS OF NEURALGIA IN ANIMAL MODELS, THE MECHANISM OF DNA METHYLATION-RELATED NEURALGIA IS SUMMARIZED, AND USEFUL TARGETS FOR EARLY DRUG INTERVENTION IN NP ARE DISCUSSED. 2022 11 3337 27 HISTONE DEACETYLASE INHIBITORS PREVENT PERSISTENT HYPERSENSITIVITY IN AN OROFACIAL NEUROPATHIC PAIN MODEL. CHRONIC OROFACIAL PAIN IS A SIGNIFICANT HEALTH PROBLEM REQUIRING IDENTIFICATION OF REGULATING PROCESSES. INVOLVEMENT OF EPIGENETIC MODIFICATIONS THAT IS REPORTED FOR HINDLIMB NEUROPATHIC PAIN EXPERIMENTAL MODELS, HOWEVER, IS LESS WELL STUDIED IN CRANIAL NERVE PAIN MODELS. THREE INDEPENDENT OBSERVATIONS REPORTED HERE ARE THE (1) EPIGENETIC PROFILE IN MOUSE TRIGEMINAL GANGLIA (TG) AFTER TRIGEMINAL INFLAMMATORY COMPRESSION (TIC) NERVE INJURY MOUSE MODEL DETERMINED BY GENE EXPRESSION MICROARRAY, (2) H3K9 ACETYLATION PATTERN IN TG BY IMMUNOHISTOCHEMISTRY, AND (3) EFFICACY OF HISTONE DEACETYLASE (HDAC) INHIBITORS TO ATTENUATE DEVELOPMENT OF HYPERSENSITIVITY. AFTER TIC INJURY, IPSILATERAL WHISKER PAD MECHANICAL SENSITIZATION DEVELOPS BY DAY 3 AND PERSISTS WELL BEYOND DAY 21 IN CONTRAST TO SHAM SURGERY. GLOBAL ACETYLATION OF H3K9 DECREASES AT DAY 21 IN IPSILATERAL TG . THIRTY-FOUR GENES ARE SIGNIFICANTLY ( P < 0.05) OVEREXPRESSED IN THE IPSILATERAL TG BY AT LEAST TWO-FOLD AT EITHER 3 OR 21 DAYS POST-TRIGEMINAL INFLAMMATORY COMPRESSION INJURY. THE THREE GENES MOST OVEREXPRESSED THREE DAYS POST-TRIGEMINAL INFLAMMATORY COMPRESSION NERVE INJURY ARE NERVE REGENERATION-ASSOCIATED GENE ATF3, UP 6.8-FOLD, AND TWO OF ITS REGENERATION-ASSOCIATED GENE EFFECTOR GENES, SPRR1A AND GAL, UP 174- AND 25-FOLD, RESPECTIVELY. ALTHOUGH TRANSCRIPTION LEVELS OF 25 OF 32 GENES SIGNIFICANTLY OVEREXPRESSED THREE DAYS POST-TRIGEMINAL INFLAMMATORY COMPRESSION RETURN TO CONSTITUTIVE LEVELS BY DAY 21, THESE THREE REGENERATION-ASSOCIATED GENES REMAIN SIGNIFICANTLY OVEREXPRESSED AT THE LATER TIME POINT. ON DAY 21, WHEN TISSUES ARE HEALED, OTHER DIFFERENTIALLY EXPRESSED GENES INCLUDE 39 OF THE TOP 50 UPREGULATED AND DOWNREGULATED GENES. REMARKABLY, PREEMPTIVE MANIPULATION OF GENE EXPRESSION WITH TWO HDAC INHIBITORS (HDACI'S), SUBERANILOHYDROXAMIC ACID (SAHA) AND MS-275, REDUCES THE MAGNITUDE AND DURATION OF WHISKER PAD MECHANICAL HYPERSENSITIVITY AND PREVENTS THE DEVELOPMENT OF A PERSISTENT PAIN STATE. THESE FINDINGS SUGGEST THAT TRIGEMINAL NERVE INJURY LEADS TO EPIGENETIC MODIFICATIONS FAVORING OVEREXPRESSION OF GENES INVOLVED IN NERVE REGENERATION AND THAT MAINTAINING TRANSCRIPTIONAL HOMEOSTASIS WITH EPIGENETIC MODIFYING DRUGS COULD HELP PREVENT THE DEVELOPMENT OF PERSISTENT PAIN. 2018 12 4579 22 N(6)-METHYLADENOSINE METHYLASE METTL3 CONTRIBUTES TO NEUROPATHIC PAIN BY EPIGENETIC SILENCING OF MU OPIOID RECEPTOR. WE AIMED AT EXPLORING THE ROLE AND MECHANISM OF METTL3-MEDIATED M(6)A MODIFICATION IN NEUROPATHIC PAIN. MALE SPRAGUE-DAWLEY RATS WERE RANDOMLY DIVIDED INTO FOUR GROUPS: SHAM OPERATION GROUP (SHAM GROUP), CHRONIC CONSTRICTION INJURY (CCI) OF THE SCIATIC NERVE MODEL GROUP (NPP GROUP), INTRATHECAL INJECTION OF VIRUS DOWN-REGULATED METTL3 + CCI MODEL GROUP (M3 + NPP GROUP) AND INTRATHECAL INJECTION OF NEGATIVE CONTROL VIRUS + CCI MODEL GROUP (SCR + NPP GROUP). THE M3 + NPP GROUP AND THE SCR + NPP GROUP WERE INTRATHECALLY INJECTED WITH VIRUS NINETEEN DAYS BEFORE OPERATION. THE PAW WITHDRAWAL MECHANICAL THRESHOLDS AND PAW WITHDRAWAL LATENCY WERE RESPECTIVELY RECORDED ONE DAY BEFORE OPERATION, THREE DAYS, FIVE DAYS AND SEVEN DAYS AFTER OPERATION. THE RATS WERE SACRIFICED ON THE SEVENTH DAY AFTER OPERATION, AND THEIR SPINAL CORD TISSUES WERE TAKEN. THE FROZEN SECTIONS OF RATS WERE PERFORMED TO OBSERVE THE EXPRESSION OF GREEN FLUORESCENT PROTEIN OF THE VIRUS. THE METHYLATION LEVEL OF RNA, THE PROTEIN EXPRESSION OF M(6)A-RELATED ENZYME (METTL3) AND MU OPIOID RECEPTOR (MOR) IN SPINAL CORD TISSUES OF THE FOUR GROUPS WERE MEASURED. DOWNREGULATION OF METTL3 HAD NO EFFECT ON THE OVERALL METHYLATION LEVEL OF THE SPINAL CORD, BUT IT COULD REGULATE THE METHYLATION LEVEL OF THE OPRM1 GENE RNA ENCODING MOR, PARTIALLY RESTORE THE EXPRESSION OF MOR, AND RELIEVE PAIN IN RATS. IN THE PROCESS OF NPP, METTL3 MAY INHIBIT THE EXPRESSION OF MOR BY REGULATING THE METHYLATION LEVEL OF OPRM1 GENE RNA ENCODING MOR, AND ULTIMATELY PROMOTE THE OCCURRENCE AND DEVELOPMENT OF NPP. 2023 13 2751 24 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 14 2565 28 EPIGENETICS INVOLVEMENT IN OXALIPLATIN-INDUCED POTASSIUM CHANNEL TRANSCRIPTIONAL DOWNREGULATION AND HYPERSENSITIVITY. PERIPHERAL NEUROPATHY IS THE MOST FREQUENT DOSE-LIMITING ADVERSE EFFECT OF OXALIPLATIN. ACUTE PAIN SYMPTOMS THAT ARE INDUCED OR EXACERBATED BY COLD OCCUR IN ALMOST ALL PATIENTS IMMEDIATELY FOLLOWING THE FIRST INFUSIONS. EVIDENCE HAS SHOWN THAT OXALIPLATIN CAUSES ION CHANNEL EXPRESSION MODULATIONS IN DORSAL ROOT GANGLIA NEURONS, WHICH ARE THOUGHT TO CONTRIBUTE TO PERIPHERAL HYPERSENSITIVITY. MOST DYSREGULATED GENES ENCODE ION CHANNELS INVOLVED IN COLD AND MECHANICAL PERCEPTION, NOTEWORTHY MEMBERS OF A SUB-GROUP OF POTASSIUM CHANNELS OF THE K2P FAMILY, TREK AND TRAAK. DOWNREGULATION OF THESE K2P CHANNELS HAS BEEN IDENTIFIED AS AN IMPORTANT TUNER OF ACUTE OXALIPLATIN-INDUCED HYPERSENSITIVITY. WE INVESTIGATED THE MOLECULAR MECHANISMS UNDERLYING THIS PERIPHERAL DYSREGULATION IN A MURINE MODEL OF NEUROPATHIC PAIN TRIGGERED BY A SINGLE OXALIPLATIN ADMINISTRATION. WE FOUND THAT OXALIPLATIN-MEDIATED TREK-TRAAK DOWNREGULATION, AS WELL AS DOWNREGULATION OF OTHER K(+) CHANNELS OF THE K2P AND KV FAMILIES, INVOLVES A TRANSCRIPTION FACTOR KNOWN AS THE NEURON-RESTRICTIVE SILENCER FACTOR (NRSF) AND ITS EPIGENETIC CO-REPRESSORS HISTONE DEACETYLASES (HDACS). NRSF KNOCKDOWN WAS ABLE TO PREVENT MOST OF THESE K(+) CHANNEL MRNA DOWNREGULATION IN MICE DORSAL ROOT GANGLION NEURONS AS WELL AS OXALIPLATIN-INDUCED ACUTE COLD AND MECHANICAL HYPERSENSITIVITY. INTERESTINGLY, PHARMACOLOGICAL INHIBITION OF CLASS I HDAC REPRODUCES THE ANTINOCICEPTIVE EFFECTS OF NRSF KNOCKDOWN AND LEADS TO AN INCREASED K(+) CHANNEL EXPRESSION IN OXALIPLATIN-TREATED MICE. 2021 15 6612 25 ULTRA-LOW-DOSE NALOXONE ENHANCES THE ANTINOCICEPTIVE EFFECT OF MORPHINE IN PTX-TREATED RATS: REGULATION ON GLOBAL HISTONE METHYLATION. OBJECTIVE: EPIGENETIC REPROGRAMMING MAY HAVE A POSSIBLE ROLE IN NEUROPATHIC PAIN DEVELOPMENT; THE PRESENT STUDY EXAMINED THE GLOBAL PATTERNS OF LYSINE HISTONE MODIFICATION. IN THIS SERIAL STUDY WE ANALYZED THE LEVELS OF HISTONE 3 LYSINE 4 MONOMETHYLATION, HISTONE 3 LYSINE 4 DIMETHYLATION, AND HISTONE 3 LYSINE 9 TRIMETHYLATION IN PERTUSSIS TOXIN (PTX)-INDUCED THERMAL HYPERALGESIC RAT SPINAL CORDS. METHODS: MALE WISTAR RATS IMPLANTED WITH AN INTRATHECAL CATHETER RECEIVED A SINGLE INTRATHECAL PTX (1 MUG IN 5 MUL SALINE) INJECTION. FOUR DAYS LATER, THEY WERE RANDOMLY ASSIGNED TO RECEIVE EITHER A SINGLE INJECTION OF SALINE, OR ULTRA-LOW-DOSE NALOXONE (15 NG IN 5 MUL SALINE), FOLLOWED BY MORPHINE (10 MUG IN 5 MUL SALINE) INJECTION 30 MINUTES LATER. RESULTS: THE RESULTS SHOWED THAT PTX INJECTION INDUCED THERMAL HYPERALGESIA AND SIGNIFICANT INCREASE OF GLOBAL HISTONE METHYLATION IN THE SPINAL CORDS. INTRATHECAL MORPHINE ALONE DID NOT AFFECT THE THERMAL HYPERALGESIA AND GLOBAL HISTONE METHYLATION. IN CONTRAST, INTRATHECAL ADMINISTRATION OF ULTRA-LOW-DOSE NALOXONE PLUS MORPHINE SIGNIFICANTLY ATTENUATED THE PTX-INDUCED THERMAL HYPERALGESIA AND DOWN-REGULATED THE GLOBAL HISTONE METHYLATION. CONCLUSION: THE RESULTS SUGGEST THAT ULTRA-LOW-DOSE NALOXONE MIGHT BE CLINICAL VALUABLE FOR NEUROPATHIC PAIN MANAGEMENT VIA REGULATING GLOBAL HISTONE MODIFICATION. 2012 16 5954 29 TBI-INDUCED NOCICEPTIVE SENSITIZATION IS REGULATED BY HISTONE ACETYLATION. CHRONIC PAIN AFTER TRAUMATIC BRAIN INJURY (TBI) IS VERY COMMON, BUT THE MECHANISMS LINKING TBI TO PAIN AND THE PAIN-RELATED INTERACTIONS OF TBI WITH PERIPHERAL INJURIES ARE POORLY UNDERSTOOD. IN THESE STUDIES WE PURSUED THE HYPOTHESIS THAT TBI PAIN SENSITIZATION IS ASSOCIATED WITH HISTONE ACETYLATION IN THE RAT LATERAL FLUID PERCUSSION MODEL. SOME ANIMALS RECEIVED HINDPAW INCISIONS IN ADDITION TO TBI TO MIMIC POLYTRAUMA. NEUROPATHOLOGICAL ANALYSIS OF BRAIN TISSUE FROM SHAM AND TBI ANIMALS REVEALED EVIDENCE OF BLEEDING, BREAKDOWN OF THE BLOOD BRAIN BARRIER, IN THE CORTEX, HIPPOCAMPUS, THALAMUS AND OTHER STRUCTURES RELATED TO PAIN SIGNAL PROCESSING. MECHANICAL ALLODYNIA WAS MEASURED IN THESE ANIMALS FOR UP TO EIGHT WEEKS POST-INJURY. INHIBITORS OF HISTONE ACETYLTRANSFERASE (HAT) AND HISTONE DEACETYLASE (HDAC) WERE USED TO PROBE THE ROLE OF HISTONE ACETYLATION IN SUCH PAIN PROCESSING. WE FOLLOWED SERUM MARKERS INCLUDING GLIAL FIBRILLARY ACIDIC PROTEIN (GFAP), NEURON-SPECIFIC ENOLASE 2 (NSE) MYELIN BASIC PROTEIN (MBP) AND S100BETA TO GAUGE TBI INJURY SEVERITY. OUR RESULTS SHOWED THAT TBI CAUSED MECHANICAL ALLODYNIA IN THE HINDPAWS OF THE RATS LASTING SEVERAL WEEKS. HINDPAWS CONTRALATERAL TO TBI SHOWED MORE RAPID AND PROFOUND SENSITIZATION THAN IPSILATERAL HINDPAWS. THE INHIBITION OF HAT USING CURCUMIN 50 MG/KG S.C REDUCED MECHANICAL SENSITIZATION WHILE THE HDAC INHIBITOR SUBEROYLANILIDE HYDROXAMIC ACID 50 MG/KG I.P. PROLONGED SENSITIZATION IN THE TBI RATS. IMMUNOHISTOCHEMICAL ANALYSES OF SPINAL CORD TISSUE LOCALIZED CHANGES IN THE LEVEL OF ACETYLATION OF THE H3K9 HISTONE MARK TO DORSAL HORN NEURONS. TAKEN TOGETHER, THESE FINDINGS DEMONSTRATE THAT TBI INDUCES SUSTAINED NOCICEPTIVE SENSITIZATION, AND CHANGES IN SPINAL NEURONAL HISTONE PROTEINS MAY PLAY AN IMPORTANT ROLE. 2017 17 6461 32 TIME-COURSE PROGRESSION OF WHOLE TRANSCRIPTOME EXPRESSION CHANGES OF TRIGEMINAL GANGLIA COMPARED TO DORSAL ROOT GANGLIA IN RATS EXPOSED TO NERVE INJURY. MECHANISMS UNDERLYING NEUROPATHIC PAIN (NP) ARE COMPLEX WITH MULTIPLE GENES, THEIR INTERACTIONS, ENVIRONMENTAL AND EPIGENETIC FACTORS BEING IMPLICATED. TRANSCRIPTIONAL CHANGES IN THE TRIGEMINAL (TG) AND DORSAL ROOT (DRG) GANGLIA HAVE BEEN IMPLICATED IN THE DEVELOPMENT AND MAINTENANCE OF NP. DESPITE EFFORTS TO UNRAVEL MOLECULAR MECHANISMS OF NP, MANY REMAIN UNKNOWN. ALSO, MOST OF THE STUDIES FOCUSED ON THE SPINAL SYSTEM. ALTHOUGH THE SPINAL AND TRIGEMINAL SYSTEMS SHARE SOME OF THE MOLECULAR MECHANISMS, DIFFERENCES EXIST. WE USED RNA-SEQUENCING TECHNOLOGY TO IDENTIFY DIFFERENTIALLY EXPRESSED GENES (DEGS) IN THE TG AND DRG AT BASELINE AND 3 TIME-POINTS FOLLOWING THE INFRAORBITAL OR SCIATIC NERVE INJURIES, RESPECTIVELY. PATHWAY ANALYSIS AND COMPARISON ANALYSIS WERE PERFORMED TO IDENTIFY DIFFERENTIALLY EXPRESSED PATHWAYS. ADDITIONALLY, UPSTREAM REGULATOR EFFECTS WERE INVESTIGATED IN THE TWO SYSTEMS. DEG (DIFFERENTIALLY EXPRESSED GENES) ANALYSES IDENTIFIED 3,225 GENES TO BE DIFFERENTIALLY EXPRESSED BETWEEN TG AND DRG IN NAIVE ANIMALS, 1,828 GENES FOUR DAYS POST INJURY, 5,644 AT DAY 8 AND 9,777 DEGS AT 21 DAYS POST INJURY. COMPARISON OF TOP ENRICHED CANONICAL PATHWAYS REVEALED THAT A NUMBER OF SIGNALING PATHWAY WAS SIGNIFICANTLY INHIBITED IN THE TG AND ACTIVATED IN THE DRG AT 21 DAYS POST INJURY. FINALLY, CORT UPSTREAM REGULATOR WAS PREDICTED TO BE INHIBITED IN THE TG WHILE EXPRESSION LEVELS OF CSF1 UPSTREAM REGULATOR WERE SIGNIFICANTLY ELEVATED IN THE DRG AT 21 DAYS POST INJURY. THIS STUDY PROVIDES A BASIS FOR FURTHER IN-DEPTH STUDIES INVESTIGATING TRANSCRIPTIONAL CHANGES, PATHWAYS, AND UPSTREAM REGULATION IN TG AND DRG IN RATS EXPOSED TO PERIPHERAL NERVE INJURIES. 2023 18 885 32 CHRONIC CONSTRICTION INJURY-INDUCED CHANGES IN CIRCULAR RNA EXPRESSION PROFILING OF THE DORSAL ROOT GANGLION IN A RAT MODEL OF NEUROPATHIC PAIN. BACKGROUND: THE PATHOGENESIS OF NEUROPATHIC PAIN (NP) HAS NOT BEEN FULLY ELUCIDATED. GENE CHANGES IN DORSAL ROOT GANGLIA (DRG) MAY CONTRIBUTE TO THE DEVELOPMENT OF NP. CIRCULAR RNAS (CIRCRNAS) ARE A CLASS OF ENDOGENOUS NONCODING RNAS THAT FORM COVALENTLY CLOSED LOOP STRUCTURES AND ARE CRUCIAL FOR GENETIC AND EPIGENETIC REGULATION. HOWEVER, LITTLE IS KNOWN ABOUT CIRCRNA CHANGES IN DRG NEURONS AFTER PERIPHERAL NERVE INJURY. METHODS: A SCIATIC NERVE CHRONIC CONSTRICTION INJURY (CCI) MODEL WAS ESTABLISHED TO INDUCE NEUROPATHIC PAIN. WE PERFORMED GENOME-WIDE CIRCRNA ANALYSIS OF FOUR PAIRED DORSAL ROOT GANGLION (DRG) SAMPLES (L4-L5) FROM CCI AND NEGATIVE CONTROL (NC) RATS USING NEXT-GENERATION SEQUENCING TECHNOLOGY. THE DIFFERENTIALLY EXPRESSED CIRCRNAS (DECIRCRNAS) WERE IDENTIFIED BY DIFFERENTIAL EXPRESSION ANALYSIS, AND THE EXPRESSION PROFILE OF CIRCRNAS WAS VALIDATED BY QUANTITATIVE PCR. GENE ONTOLOGY AND KYOTO ENCYCLOPEDIA OF GENES AND GENOMES ANALYSES WERE PERFORMED TO PREDICT THE FUNCTION OF DECIRCRNAS. RESULTS: A TOTAL OF 374 DECIRCRNAS WERE IDENTIFIED BETWEEN CCI AND NC RATS USING CIRCRNA HIGH-THROUGHPUT SEQUENCING. AMONG THEM, 290 WERE UPREGULATED AND 84 WERE DOWNREGULATED IN THE CCI GROUP. THE EXPRESSION LEVELS OF NINE DECIRCRNAS WERE VALIDATED BY QPCR. FUNCTIONAL ANNOTATION ANALYSIS SHOWED THAT THE DECIRCRNAS WERE MAINLY ENRICHED IN PATHWAYS AND FUNCTIONS, INCLUDING 'DOPAMINERGIC SYNAPSE,' 'RENIN SECRETION,' 'MITOGEN-ACTIVATED PROTEIN KINASE SIGNALING PATHWAY,' AND 'NEUROGENESIS.' COMPETING ENDOGENOUS RNA ANALYSIS SHOWED THAT THE TOP 50 CIRCRNAS EXHIBITED INTERACTIONS WITH FOUR PAIN-RELATED MICRORNAS (MIRNAS). CIRC:CHR2:33950934-33955969 WAS THE LARGEST NODE IN THE CIRCRNA-MIRNA INTERACTION NETWORK. CONCLUSIONS: PERIPHERAL NERVE INJURY-INDUCED NEUROPATHIC PAIN LED TO CHANGES IN THE COMPREHENSIVE EXPRESSION PROFILE OF CIRCRNAS IN THE DRG OF RATS. DECIRCRNAS MAY ADVANCE OUR UNDERSTANDING OF THE MOLECULAR MECHANISMS UNDERLYING NEUROPATHIC PAIN. 2022 19 6472 31 TNFALPHA IN THE TRIGEMINAL NOCICEPTIVE SYSTEM IS CRITICAL FOR TEMPOROMANDIBULAR JOINT PAIN. PREVIOUS STUDIES HAVE SHOWN THAT TUMOR NECROSIS FACTOR ALPHA (TNFALPHA) IS SIGNIFICANTLY INCREASED IN COMPLETE FREUND'S ADJUVANT (CFA)-TREATED TEMPOROMANDIBULAR JOINT (TMJ) TISSUES. HOWEVER, IT IS UNCLEAR WHETHER TNFALPHA IN THE TRIGEMINAL NOCICEPTIVE SYSTEM CONTRIBUTES TO THE DEVELOPMENT OF TMJ PAIN. IN THE PRESENT STUDY, WE INVESTIGATED THE ROLE OF TNFALPHA IN TRIGEMINAL GANGLIA (TG) AND SPINAL TRIGEMINAL NUCLEUS CAUDALIS (SP5C) IN CFA-INDUCED INFLAMMATORY TMJ PAIN. INTRA-TMJ INJECTION OF CFA (10 MUL, 5 MG/ML) INDUCED INFLAMMATORY PAIN IN THE TRIGEMINAL NERVE V2- AND V3-INNERVATED SKIN AREAS OF WT MICE, WHICH WAS PRESENT ON DAY 1 AFTER CFA AND PERSISTED FOR AT LEAST 10 DAYS. TNFALPHA IN BOTH TG AND SP5C OF WT MICE WAS UPREGULATED AFTER CFA INJECTION. THE CFA-INDUCED TMJ PAIN WAS SIGNIFICANTLY INHIBITED IN TNFALPHA KO MICE. THE IMMUNOFLUORESCENCE STAINING SHOWED THAT INTRA-TMJ CFA INJECTION NOT ONLY ENHANCED CO-LOCALIZATION OF TNFALPHA WITH IBA1 (A MARKER FOR MICROGLIA) IN BOTH TG AND SP5C BUT ALSO MARKEDLY INCREASED THE EXPRESSION OF TNFALPHA IN THE SP5C NEURONS. BY THE METHYLATED DNA IMMUNOPRECIPITATION ASSAY, WE ALSO FOUND THAT DNA METHYLATION AT THE TNF GENE PROMOTER REGION IN THE TG WAS DRAMATICALLY DIMINISHED AFTER CFA INJECTION, INDICATING THAT EPIGENETIC REGULATION MAY BE INVOLVED IN THE CFA-ENHANCED TNFALPHA EXPRESSION IN OUR MODEL. OUR RESULTS SUGGEST THAT TNFALPHA IN THE TRIGEMINAL NOCICEPTIVE SYSTEM PLAYS A CRITICAL ROLE IN CFA-INDUCED INFLAMMATORY TMJ PAIN. 2019 20 4616 23 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