1 1492 145 DNA HYDROXYMETHYLATION BY TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE 1 AND 3 REGULATES NOCICEPTIVE SENSITIZATION IN A CHRONIC INFLAMMATORY PAIN MODEL. BACKGROUND: TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE CONVERTS 5-METHYLCYTOSINE IN DNA TO 5-HYDROXYMETHYLCYTOSINE, WHICH PLAYS AN IMPORTANT ROLE IN GENE TRANSCRIPTION. ALTHOUGH 5-HYDROXYMETHYLCYTOSINE IS ENRICHED IN MAMMALIAN NEURONS, ITS REGULATORY FUNCTION IN NOCICEPTIVE INFORMATION PROCESSING IS UNKNOWN. METHODS: THE GLOBAL LEVELS OF 5-HYDROXYMETHYLCYTOSINE AND TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE WERE MEASURED IN SPINAL CORDS IN MICE TREATED WITH COMPLETE FREUND'S ADJUVANT. IMMUNOBLOTTING, IMMUNOHISTOCHEMISTRY, AND BEHAVIORAL TESTS WERE USED TO EXPLORE THE DOWNSTREAM TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE-DEPENDENT SIGNALING PATHWAY. RESULTS: COMPLETE FREUND'S ADJUVANT-INDUCED NOCICEPTION INCREASED THE MEAN LEVELS (+/- SD) OF SPINAL 5-HYDROXYMETHYLCYTOSINE (178 +/- 34 VS. 100 +/- 21; P = 0.0019), TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE-1 (0.52 +/- 0.11 VS. 0.36 +/- 0.064; P = 0.0088), AND TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE-3 (0.61 +/- 0.13 VS. 0.39 +/- 0.08; P = 0.0083) COMPARED WITH LEVELS IN CONTROL MICE (N = 6/GROUP). THE KNOCKDOWN OF TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE-1 OR TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE-3 ALLEVIATED THERMAL HYPERALGESIA AND MECHANICAL ALLODYNIA, WHEREAS OVEREXPRESSION CYTOSINETHEM IN NAIVE MICE (N = 6/GROUP). DOWN-REGULATION OF SPINAL TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE-1 AND TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE-3 ALSO REVERSED THE INCREASES IN FOS EXPRESSION (123 +/- 26 VS. 294 +/- 6; P = 0.0031; AND 140 +/- 21 VS. 294 +/- 60; P = 0.0043, RESPECTIVELY; N = 6/GROUP), 5-HYDROXYMETHYLCYTOSINE LEVELS IN THE STAT3 PROMOTER (75 +/- 16.1 VS. 156 +/- 28.9; P = 0.0043; AND 91 +/- 19.1 VS. 156 +/- 28.9; P = 0.0066, RESPECTIVELY; N = 5/GROUP), AND CONSEQUENT STAT3 EXPRESSION (93 +/- 19.6 VS. 137 +/- 27.5; P = 0.035; AND 72 +/- 15.2 VS. 137 +/- 27.5; P = 0.0028, RESPECTIVELY; N = 5/GROUP) IN COMPLETE FREUND'S ADJUVANT-TREATED MICE. CONCLUSIONS: THIS STUDY REVEALS A NOVEL EPIGENETIC MECHANISM FOR TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE-1 AND TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE-3 IN THE MODULATION OF SPINAL NOCICEPTIVE INFORMATION VIA TARGETING OF STAT3. 2017 2 5066 33 PHTHALATES SUPPRESS TYPE I INTERFERON IN HUMAN PLASMACYTOID DENDRITIC CELLS VIA EPIGENETIC REGULATION. BACKGROUND: EXPOSURE TO ENVIRONMENTAL ENDOCRINE-DISRUPTING CHEMICALS (EDCS) IS ASSOCIATED WITH ALLERGY, CHRONIC INFLAMMATION, AND IMMUNODEFICIENCY. PHTHALATES, THE COMMON EDCS USED IN PLASTIC INDUSTRY, MAY ACT AS ADJUVANTS TO DISRUPT IMMUNE SYSTEM AND ENHANCE ALLERGY. PLASMACYTOID DCS (PDCS) ARE PREDOMINANT CELLS SECRETING TYPE I INTERFERON (IFN) AGAINST INFECTION AND ARE PROFESSIONAL ANTIGEN-PRESENTING CELLS IN REGULATING ADAPTIVE IMMUNITY. HOWEVER, THE EFFECTS OF PHTHALATES ON THE FUNCTION OF PDCS ARE UNKNOWN. METHODS: CIRCULATING PDCS WERE ISOLATED FROM HEALTHY SUBJECTS, WERE PRETREATED WITH DIETHYLHEXYL PHTHALATE (DEHP) AND BUTYL BENZYL PHTHALATE (BBP), AND WERE STIMULATED WITH TOLL-LIKE RECEPTOR (TLR)-9 AGONIST CPG. IFN-ALPHA/IFN-BETA LEVELS, SURFACE MARKERS, AND T-CELL STIMULATORY FUNCTION WERE INVESTIGATED USING ELISA, FLOW CYTOMETRY, AND PDC/T-CELL COCULTURE ASSAY. MECHANISMS WERE INVESTIGATED USING RECEPTOR ANTAGONISTS, PATHWAY INHIBITORS, WESTERN BLOTTING, AND CHROMATIN IMMUNOPRECIPITATION. RESULTS: DIETHYLHEXYL PHTHALATE AND BUTYL BENZYL PHTHALATE SUPPRESSED CPG-INDUCED IFN-ALPHA/IFN-BETA EXPRESSION IN PDCS, AND THE EFFECT WAS REVERSED BY ARYL HYDROCARBON RECEPTOR (AHR) ANTAGONIST. DIETHYLHEXYL PHTHALATE SUPPRESSED CPG-ACTIVATED MITOGEN-ACTIVATED PROTEIN KINASE (MAPK)-MEK1/2-ERK-ELK1 AND NFKAPPAB SIGNALING PATHWAYS. DIETHYLHEXYL PHTHALATE SUPPRESSED CPG-INDUCED INTERFERON REGULATORY FACTOR (IRF)-7 EXPRESSION BY SUPPRESSING HISTONE H3K4 TRIMETHYLATION AT IRF7 GENE PROMOTER REGION THROUGH INHIBITING TRANSLOCATION OF H3K4-SPECIFIC TRIMETHYLTRANSFERASE WDR5 FROM CYTOPLASM INTO NUCLEUS. BUTYL BENZYL PHTHALATE OR DIETHYLHEXYL PHTHALATE-TREATED PDCS SUPPRESSED IFN-GAMMA BUT ENHANCED IL-13 PRODUCTION BY CD4+ T CELLS. CONCLUSION: PHTHALATES MAY INTERFERE WITH IMMUNITY AGAINST INFECTION AND PROMOTE THE DEVIATION OF TH2 RESPONSE TO INCREASE ALLERGY BY ACTING ON HUMAN PDCS VIA SUPPRESSING IFN-ALPHA/IFN-BETA EXPRESSION AND MODULATING THE ABILITY TO STIMULATE T-CELL RESPONSES. 2013 3 5328 40 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 4 31 18 A CASE OF INFECTION-ASSOCIATED ANTIPROTEINASE-3-NEGATIVE CYTOPLASMIC ANTINEUTROPHIL CYTOPLASMIC ANTIBODY PAUCI-IMMUNE FOCAL NECROTIZING GLOMERULONEPHRITIS. WE PRESENT THE CASE OF A MAN WITH GRAM-NEGATIVE SEPSIS AND EXPOSURE TO ORAL SILICA WHO DEVELOPED PAUCI-IMMUNE FOCAL NECROTIZING GLOMERULONEPHRITIS (PI-FNGN) IN THE SETTING OF A SUBACUTE POLYMICROBIAL CENTRAL VENOUS LINE (CVL) INFECTION. HE DEVELOPED A CYTOPLASMIC ANTINEUTROPHIL CYTOPLASMIC AUTOANTIBODY (C-ANCA) THAT WAS ANTIPROTEINASE-3 (PR-3) AND ANTIMYELOPEROXIDASE (MPO) ANTIBODY NEGATIVE. WE BELIEVE THIS IS THE FIRST REPORTED CASE OF GRAM-NEGATIVE SEPSIS-ASSOCIATED PI-FNGN. CHRONIC SILICA EXPOSURE IS A LEADING ENVIRONMENTAL RISK FACTOR IN THE DEVELOPMENT OF ANCA VASCULITIS. ORAL SILICA IS A COMMON PHARMACEUTICAL ADDITIVE AND ITS BIOAVAILABILITY IS BEING RECOGNIZED. ORAL SILICA, THEREFORE, MAY ALSO BE A RISK FOR DEVELOPMENT OF AUTOREACTIVITY. THE PI-FNGN RESOLVED WITH ANTIBIOTIC THERAPY ALONE. THE C-ANCA TITER DECLINED AS THE PI-FNGN RESOLVED. THE CASE SUPPORTS EXPERIMENTAL AND OBSERVATIONAL RESEARCH THAT ENVIRONMENTAL EXPOSURES ACT AS ADJUVANTS FOR AN IMMUNE RESPONSE AND ALSO PROVIDE EPIGENETIC TRIGGERS FOR AUTOREACTIVITY. THE C-ANCA WAS NEGATIVE FOR PR-3, ITS MAJOR ANTIGEN. C-ANCA ANTIGEN SPECIFICITY MAY DEPEND ON THE PATHOGENESIS OF THE UNDERLYING DISEASE, POTENTIALLY ELICITED BY A CROSS-REACTION OF AN ANTIBODY TO FOREIGN AND SELF TARGET ANTIGEN SEQUENCE HOMOLOGY OR ALTERNATIVELY ELICITED BY ANTIGENIC EPITOPE SPREAD. 2010 5 2452 38 EPIGENETIC SUPPRESSION OF POTASSIUM-CHLORIDE CO-TRANSPORTER 2 EXPRESSION IN INFLAMMATORY PAIN INDUCED BY COMPLETE FREUND'S ADJUVANT (CFA). BACKGROUND: MULTIPLE MECHANISMS CONTRIBUTE TO THE STIMULUS-EVOKED PAIN HYPERSENSITIVITY THAT MAY BE EXPERIENCED AFTER PERIPHERAL INFLAMMATION. PERSISTENT PATHOLOGICAL STIMULI IN MANY PAIN CONDITIONS AFFECT THE EXPRESSION OF CERTAIN GENES THROUGH EPIGENETIC ALTERNATIONS. THE MAIN PURPOSE OF OUR STUDY WAS TO INVESTIGATE THE ROLE OF EPIGENETIC MODIFICATION ON POTASSIUM-CHLORIDE CO-TRANSPORTER 2 (KCC2) GENE EXPRESSION IN THE PERSISTENCE OF INFLAMMATORY PAIN. METHODS: PERSISTENT INFLAMMATORY PAIN WAS INDUCED THROUGH THE INJECTION OF COMPLETE FREUND'S ADJUVANT (CFA) IN THE LEFT HIND PAW OF RATS. ACETYL-HISTONE H3 AND H4 LEVEL WAS DETERMINED BY CHROMATIN IMMUNOPRECIPITATION IN THE SPINAL DORSAL HORN. PAIN BEHAVIOUR AND INHIBITORY SYNAPTIC FUNCTION OF SPINAL CORD WERE DETERMINED BEFORE AND AFTER CFA INJECTION. KCC2 EXPRESSION WAS DETERMINED BY REAL TIME RT-PCR AND WESTERN BLOT. INTRATHECAL KCC2 SIRNA (2 MUG PER 10 MUL PER RAT) OR HDAC INHIBITOR (10 MUG PER 10 MUL PER RAT) WAS INJECTED ONCE DAILY FOR 3 DAYS BEFORE CFA INJECTION. RESULTS: PERSISTENT INFLAMMATORY PAIN EPIGENETICALLY SUPPRESSED KCC2 EXPRESSION THROUGH HISTONE DEACETYLASE (HDAC)-MEDIATED HISTONE HYPOACETYLATION, RESULTING IN DECREASED INHIBITORY SIGNALLING EFFICACY. KCC2 KNOCK-DOWN CAUSED BY INTRATHECAL ADMINISTRATION OF KCC2 SIRNA IN NAIVE RATS REDUCED KCC2 EXPRESSION IN THE SPINAL CORD, LEADING TO SENSITIZED PAIN BEHAVIOURS AND IMPAIRED INHIBITORY SYNAPTIC TRANSMISSION IN THEIR SPINAL CORDS. MOREOVER, INTRATHECAL HDAC INHIBITOR INJECTION IN CFA RATS INCREASED KCC2 EXPRESSION, PARTIALLY RESTORING THE SPINAL INHIBITORY SYNAPTIC TRANSMISSION AND RELIEVING THE SENSITIZED PAIN BEHAVIOUR. CONCLUSION: THESE FINDINGS SUGGEST THAT THE TRANSCRIPTION OF SPINAL KCC2 IS REGULATED BY HISTONE ACETYLATION EPIGENETICALLY FOLLOWING CFA. SIGNIFICANCE: PERSISTENT PAIN SUPPRESSES KCC2 EXPRESSION THROUGH HDAC-MEDIATED HISTONE HYPOACETYLATION AND CONSEQUENTLY IMPAIRS THE INHIBITORY FUNCTION OF INHIBITORY INTERNEURONS. DRUGS SUCH AS HDAC INHIBITORS THAT SUPPRESS THE INFLUENCES OF PERSISTENT PAIN ON THE EXPRESSION OF KCC2 MAY SERVE AS A NOVEL ANALGESIC. 2017 6 4297 41 MICRORNA-1224 SPLICING CIRCULARRNA-FILIP1L IN AN AGO2-DEPENDENT MANNER REGULATES CHRONIC INFLAMMATORY PAIN VIA TARGETING UBR5. DYSFUNCTIONS OF GENE TRANSCRIPTION AND TRANSLATION IN THE NOCICEPTIVE PATHWAYS PLAY THE CRITICAL ROLE IN DEVELOPMENT AND MAINTENANCE OF CHRONIC PAIN. CIRCULAR RNAS (CIRCRNAS) ARE EMERGING AS NEW PLAYERS IN REGULATION OF GENE EXPRESSION, BUT WHETHER AND HOW CIRCRNAS ARE INVOLVED IN CHRONIC PAIN REMAIN ELUSIVE. WE SHOWED HERE THAT COMPLETE FREUND'S ADJUVANT-INDUCED CHRONIC INFLAMMATION PAIN SIGNIFICANTLY INCREASED CIRCRNA-FILIP1L (FILAMIN A INTERACTING PROTEIN 1-LIKE) EXPRESSION IN SPINAL NEURONS OF MICE. BLOCKAGE OF THIS INCREASE ATTENUATED COMPLETE FREUND'S ADJUVANT-INDUCED NOCICEPTIVE BEHAVIORS, AND OVEREXPRESSION OF SPINAL CIRCRNA-FILIP1L IN NAIVE MICE MIMICKED THE NOCICEPTIVE BEHAVIORS AS EVIDENCED BY DECREASED THERMAL AND MECHANICAL NOCICEPTIVE THRESHOLD. FURTHERMORE, WE FOUND THAT MATURE CIRCRNA-FILIP1L EXPRESSION WAS NEGATIVELY REGULATED BY MIRNA-1224 VIA BINDING AND SPLICING OF PRECURSOR OF CIRCRNA-FILIP1L (PRE-CIRCRNA-FILIP1L) IN THE ARGONAUTE-2 (AGO2)-DEPENDENT MANNER. INCREASE OF SPINAL CIRCRNA-FILIP1L EXPRESSION RESULTED FROM THE DECREASE OF MIRNA-1224 EXPRESSION UNDER CHRONIC INFLAMMATION PAIN STATE. MIRNA-1224 KNOCKDOWN OR AGO2 OVEREXPRESSION INDUCED NOCICEPTIVE BEHAVIORS IN NAIVE MICE, WHICH WAS PREVENTED BY THE KNOCKDOWN OF SPINAL CIRCRNA-FILIP1L. FINALLY, WE DEMONSTRATED THAT A UBIQUITIN PROTEIN LIGASE E3 COMPONENT N-RECOGNIN 5 (UBR5), VALIDATED AS A TARGET OF CIRCRNA-FILIP1L, PLAYS A PIVOTAL ROLE IN REGULATION OF NOCICEPTION BY SPINAL CIRCRNA-FILIP1L. THESE DATA SUGGEST THAT MIRNA-1224-MEDIATED AND AGO2-DEPENDENT MODULATION OF SPINAL CIRCRNA-FILIP1L EXPRESSION REGULATES NOCICEPTION VIA TARGETING UBR5, REVEALING A NOVEL EPIGENETIC MECHANISM OF INTERACTION BETWEEN MIRNA AND CIRCRNA IN CHRONIC INFLAMMATION PAIN.SIGNIFICANCE STATEMENT CIRCRNAS ARE EMERGING AS NEW PLAYERS IN REGULATION OF GENE EXPRESSION. HERE, WE FOUND THAT THE INCREASE OF CIRCRNA-FILIP1L MEDIATED BY MIRNA-1224 IN AN AGO2-DEPENDENT WAY IN THE SPINAL CORD IS INVOLVED IN REGULATION OF NOCICEPTION VIA TARGETING UBR5 OUR STUDY REVEALS A NOVEL EPIGENETIC MECHANISM OF INTERACTION BETWEEN MIRNA AND CIRCRNA IN CHRONIC INFLAMMATION PAIN. 2019 7 2203 39 EPIGENETIC MODIFICATION OF SPINAL MIR-219 EXPRESSION REGULATES CHRONIC INFLAMMATION PAIN BY TARGETING CAMKIIGAMMA. EMERGING EVIDENCE HAS SHOWN THAT MIRNA-MEDIATED GENE EXPRESSION MODULATION CONTRIBUTES TO CHRONIC PAIN, BUT ITS FUNCTIONAL REGULATORY MECHANISM REMAINS UNKNOWN. HERE, WE FOUND THAT COMPLETE FREUND'S ADJUVANT (CFA)-INDUCED CHRONIC INFLAMMATION PAIN SIGNIFICANTLY REDUCED MIRNA-219 (MIR-219) EXPRESSION IN MICE SPINAL NEURONS. FURTHERMORE, THE EXPRESSION OF SPINAL CAMKIIGAMMA, AN EXPERIMENTALLY VALIDATED TARGET OF MIR-219, WAS INCREASED IN CFA MICE. OVEREXPRESSION OF SPINAL MIR-219 PREVENTED AND REVERSED THERMAL HYPERALGESIA AND MECHANICAL ALLODYNIA AND SPINAL NEURONAL SENSITIZATION INDUCED BY CFA. CONCURRENTLY, INCREASED EXPRESSION OF SPINAL CAMKIIGAMMA WAS REVERSED BY MIR-219 OVEREXPRESSION. DOWNREGULATION OF SPINAL MIR-219 IN NAIVE MICE INDUCED PAIN-RESPONSIVE BEHAVIORS AND INCREASED P-NMDAR1 EXPRESSION, WHICH COULD BE INHIBITED BY KNOCKDOWN OF CAMKIIGAMMA. BISULFITE SEQUENCING SHOWED THAT CFA INDUCED THE HYPERMETHYLATION OF CPG ISLANDS IN THE MIR-219 PROMOTER. TREATMENT WITH DEMETHYLATION AGENT 5'-AZA-2'-DEOXYCYTIDINE MARKEDLY ATTENUATED PAIN BEHAVIOR AND SPINAL NEURONAL SENSITIZATION, WHICH WAS ACCOMPANIED WITH THE INCREASE OF SPINAL MIR-219 AND DECREASE OF CAMKIIGAMMA EXPRESSION. TOGETHER, WE CONCLUDE THAT METHYLATION-MEDIATED EPIGENETIC MODIFICATION OF SPINAL MIR-219 EXPRESSION REGULATES CHRONIC INFLAMMATORY PAIN BY TARGETING CAMKIIGAMMA. 2014 8 1220 27 CRISPR/CAS9-BASED MUTAGENESIS OF HISTONE H3.1 IN SPINAL DYNORPHINERGIC NEURONS ATTENUATES THERMAL SENSITIVITY IN MICE. BURN INJURY IS A TRAUMA RESULTING IN TISSUE DEGRADATION AND SEVERE PAIN, WHICH IS PROCESSED FIRST BY NEURONAL CIRCUITS IN THE SPINAL DORSAL HORN. WE HAVE RECENTLY SHOWN THAT IN MICE, EXCITATORY DYNORPHINERGIC (PDYN) NEURONS PLAY A PIVOTAL ROLE IN THE RESPONSE TO BURN-INJURY-ASSOCIATED TISSUE DAMAGE VIA HISTONE H3.1 PHOSPHORYLATION-DEPENDENT SIGNALING. AS PDYN NEURONS WERE MOSTLY ASSOCIATED WITH MECHANICAL ALLODYNIA, THEIR INVOLVEMENT IN THERMONOCICEPTION HAD TO BE FURTHER ELUCIDATED. USING A CUSTOM-MADE AAV9_MUTH3.1 VIRUS COMBINED WITH THE CRISPR/CAS9 SYSTEM, HERE WE PROVIDE EVIDENCE THAT BLOCKING HISTONE H3.1 PHOSPHORYLATION AT POSITION SERINE 10 (S10) IN SPINAL PDYN NEURONS SIGNIFICANTLY INCREASES THE THERMAL NOCICEPTIVE THRESHOLD IN MICE. IN CONTRAST, NEITHER MECHANOSENSATION NOR ACUTE CHEMONOCICEPTION WAS AFFECTED BY THE TRANSGENIC MANIPULATION OF HISTONE H3.1. THESE RESULTS SUGGEST THAT BLOCKING RAPID EPIGENETIC TAGGING OF S10H3 IN SPINAL PDYN NEURONS ALTERS ACUTE THERMOSENSATION AND THUS EXPLAINS THE INVOLVEMENT OF PDYN CELLS IN THE IMMEDIATE RESPONSE TO BURN-INJURY-ASSOCIATED TISSUE DAMAGE. 2022 9 5018 30 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 10 3154 33 GLUN2B/CAMKII MEDIATES CFA-INDUCED HYPERALGESIA VIA HDAC4-MODIFIED SPINAL COX2 TRANSCRIPTION. HISTONE DEACETYLASE 4 (HDAC4), WHICH ACTIVELY SHUTTLES BETWEEN THE NUCLEUS AND CYTOPLASM, IS AN ATTRACTIVE CANDIDATE FOR A REPRESSOR MECHANISM IN EPIGENETIC MODIFICATION. HOWEVER, THE POTENTIAL ROLE OF HDAC4-DEPENDENT EPIGENETICS IN THE NEURAL PLASTICITY UNDERLYING THE DEVELOPMENT OF INFLAMMATORY PAIN HAS NOT BEEN WELL ESTABLISHED. BY INJECTING COMPLETE FREUND'S ADJUVANT (CFA) INTO THE HIND-PAW OF SPRAGUE-DAWLEY RATS (200-250 G), WE FOUND ANIMALS DISPLAYED BEHAVIORAL HYPERALGESIA WAS ACCOMPANIED WITH HDAC4 PHOSPHORYLATION AND CYTOPLASMIC REDISTRIBUTION IN THE DORSAL HORN NEURONS. CYTOPLASMIC HDAC4 RETENTION LED TO ITS UNCOUPLING WITH THE COX2 PROMOTER, HENCE PROMPTING SPINAL COX2 TRANSCRIPTION AND EXPRESSION IN THE DORSAL HORN. MOREOVER, THE GLUN2B-BEARING N-METHYL-D-ASPARTATE RECEPTOR (GLUN2B-NMDAR)/CALMODULIN-DEPENDENT PROTEIN KINASE II (CAMKII) ACTED AS AN UPSTREAM CASCADE TO FACILITATE HDAC4 PHOSPHORYLATION/REDISTRIBUTION-ASSOCIATED SPINAL COX2 EXPRESSION AFTER INFLAMMATORY INSULTS. THE RESULTS OF THIS PILOT STUDY DEMONSTRATED THAT THE DEVELOPMENT AND/OR MAINTENANCE OF INFLAMMATORY PAIN INVOLVED THE SPINAL HDAC4-DEPENDENT EPIGENETIC MECHANISMS. OUR FINDINGS OPEN UP A NEW AVENUE FOR THE DEVELOPMENT OF A NOVEL MEDICAL STRATEGY FOR THE RELIEF OF INFLAMMATORY PAIN. 2018 11 1033 23 CITRULLINATION OF AUTOANTIGENS IMPLICATES NETOSIS IN THE INDUCTION OF AUTOIMMUNITY. TOLERANCE BLOCKS THE EXPRESSION OF AUTOANTIBODIES, WHEREAS AUTOIMMUNITY PROMOTES IT. HOW TOLERANCE BREAKS AND AUTOANTIBODY PRODUCTION BEGINS THUS ARE CRUCIAL QUESTIONS FOR UNDERSTANDING AND TREATMENT OF AUTOIMMUNE DISEASES. EVIDENCE IMPLICATES CELL DEATH AND AUTOANTIGEN MODIFICATIONS IN THE INITIATION OF AUTOIMMUNE REACTIONS. ONE FORM OF NEUTROPHIL CELL DEATH CALLED NETOSIS DESERVES ATTENTION BECAUSE IT REQUIRES THE POST-TRANSLATIONAL MODIFICATION OF HISTONES AND RESULTS IN THE EXTRACELLULAR RELEASE OF CHROMATIN. NETOSIS RECEIVED ITS NAME FROM NET, THE ACRONYM GIVEN TO NEUTROPHIL EXTRACELLULAR TRAP. THE EXTRACELLULAR CHROMATIN INCORPORATES HISTONES IN WHICH ARGININES HAVE BEEN CONVERTED TO CITRULLINES BY PEPTIDYLARGININE DEIMINASE IV (PAD4). THE DEIMINATED CHROMATIN MAY FUNCTION TO CAPTURE OR 'TRAP' BACTERIAL PATHOGENS, THUS GENERATING AN EXTRACELLULAR COMPLEX OF DEIMINATED HISTONES AND BACTERIAL CELL ADJUVANTS. THE COMPLEX OF BACTERIAL ANTIGENS AND DEIMINATED CHROMATIN MAY BE INTERNALISED BY HOST PHAGOCYTES DURING ACUTE INFLAMMATORY CONDITIONS, AS ARISE DURING BACTERIAL INFECTIONS OR CHRONIC AUTOINFLAMMATORY DISORDERS. THE UPTAKE AND PROCESSING OF DEIMINATED CHROMATIN TOGETHER WITH BACTERIAL ADJUVANTS BY PHAGOCYTES MAY INDUCE THE PRESENTATION OF MODIFIED HISTONE EPITOPES AND CO-STIMULATION, THUS YIELDING A POWERFUL STIMULUS TO BREAK TOLERANCE. AUTOANTIBODIES TO DEIMINATED HISTONES ARE PREVALENT IN FELTY'S SYNDROME PATIENTS AND ARE PRESENT IN SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) AND PATIENTS WITH RHEUMATOID ARTHRITIS (RA). THESE OBSERVATIONS CLEARLY IMPLICATE HISTONE DEIMINATION AS AN EPIGENETIC MARK THAT CAN ACT AS AN AUTOANTIBODY STIMULANT. 2014 12 3955 28 LONG MARCH TOWARD SAFE AND EFFECTIVE ANALGESIA BY ENHANCING GENE EXPRESSION OF KCC2: FIRST STEPS TAKEN. LOW INTRANEURONAL CHLORIDE IN SPINAL CORD DORSAL HORN PAIN RELAY NEURONS IS CRITICAL FOR PHYSIOLOGIC TRANSMISSION OF PRIMARY PAIN AFFERENTS BECAUSE LOW INTRANEURONAL CHLORIDE DICTATES WHETHER GABA-ERGIC AND GLYCIN-ERGIC NEUROTRANSMISSION IS INHIBITORY. IF THE NEURONAL CHLORIDE ELEVATES TO PATHOLOGIC LEVELS, THEN SPINAL CORD PRIMARY PAIN RELAY BECOMES LEAKY AND EXHIBITS THE BEHAVIORAL HALLMARKS OF PATHOLOGIC PAIN, NAMELY HYPERSENSITIVITY AND ALLODYNIA. LOW CHLORIDE IN SPINAL CORD DORSAL HORN NEURONS IS MAINTAINED BY PROPER GENE EXPRESSION OF KCC2 AND SUSTAINED PHYSIOLOGIC FUNCTION OF THE KCC2 CHLORIDE EXTRUDING ELECTRONEUTRAL TRANSPORTER. PERIPHERAL NERVE INJURY AND OTHER FORMS OF NEURAL INJURY EVOKE GREATLY DIMINISHED KCC2 GENE EXPRESSION AND SUBSEQUENT CORRUPTION OF INHIBITORY NEUROTRANSMISSION IN THE SPINAL CORD DORSAL HORN, THUS CAUSING DERAILMENT OF THE GATE FUNCTION FOR PAIN. HERE I REVIEW KEY DISCOVERIES THAT HAVE HELPED US UNDERSTAND THESE FUNDAMENTALS, AND FOCUS ON RECENT INSIGHTS RELATING TO THE DISCOVERY OF KCC2 GENE EXPRESSION ENHANCING COMPOUNDS VIA COMPOUND SCREENS IN NEURONS. ONE SUCH STUDY CHARACTERIZED THE KINASE INHIBITOR, KENPAULLONE, MORE IN-DEPTH, REVEALING ITS FUNCTION AS A ROBUST AND LONG-LASTING ANALGESIC IN PRECLINICAL MODELS OF NERVE INJURY AND CANCER BONE PAIN, ALSO ELUCIDATING ITS MECHANISM OF ACTION VIA GSK3BETA INHIBITION, DIMINISHING DELTA-CATENIN PHOSPHORYLATION, AND FACILITATING ITS NUCLEAR TRANSFER AND SUBSEQUENT ENHANCEMENT OF KCC2 GENE EXPRESSION BY DE-REPRESSING KAISO EPIGENETIC TRANSCRIPTIONAL REGULATOR. FUTURE DIRECTIONS RE KCC2 GENE EXPRESSION ENHANCEMENT ARE DISCUSSED, NAMELY COMBINATION WITH OTHER ANALGESICS AND ANALGESIC METHODS, SUCH AS SPINAL CORD STIMULATION AND ELECTROACUPUNCTURE, GENE THERAPY, AND LEVERAGING KCC2 GENE EXPRESSION-ENHANCING NANOMATERIALS. 2022 13 2450 36 EPIGENETIC SUPPRESSION OF LIVER X RECEPTOR BETA IN ANTERIOR CINGULATE CORTEX BY HDAC5 DRIVES CFA-INDUCED CHRONIC INFLAMMATORY PAIN. BACKGROUND: LIVER X RECEPTORS (LXRS), INCLUDING LXRALPHA AND LXRBETA, ARE KEY REGULATORS OF TRANSCRIPTIONAL PROGRAMS FOR BOTH CHOLESTEROL HOMEOSTASIS AND INFLAMMATION IN THE BRAIN. HERE, THE MODES OF ACTION OF LXRS AND THE EPIGENETIC MECHANISMS REGULATING LXRBETA EXPRESSION IN ANTERIOR CINGULATE CORTEX (ACC) OF CHRONIC INFLAMMATORY PAIN (CIP) ARE INVESTIGATED. METHODS: THE DEFICIT OF LXR ISOFORM AND ANALGESIC EFFECT OF LXR ACTIVATION BY GW3965 WERE EVALUATED USING THE MOUSE MODEL OF CIP INDUCED BY HINDPAW INJECTION OF COMPLETE FREUND'S ADJUVANT (CFA). THE MECHANISMS INVOLVED IN GW-MEDIATED ANALGESIC EFFECTS WERE ANALYZED WITH IMMUNOHISTOCHEMICAL METHODS, ELISA, CO-IMMUNOPRECIPITATION (CO-IP), WESTERN BLOT, AND ELECTROPHYSIOLOGICAL RECORDING. THE EPIGENETIC REGULATION OF LXRBETA EXPRESSION WAS INVESTIGATED BY CHROMATIN IMMUNOPRECIPITATION, QUANTITATIVE REAL-TIME PCR, AND SEQUENCING. RESULTS: WE REVEALED THAT CFA INSULT LED TO LXRBETA REDUCTION IN ACC, WHICH WAS ASSOCIATED WITH UPREGULATED EXPRESSION OF HISTONE DEACETYLASE 5 (HDAC5), AND KNOCKDOWN OF LXRBETA BY SHRNA LED TO THERMAL HYPERALGESIA. CO-IP SHOWED THAT LXRBETA INTERACTED WITH NF-KAPPAB P65 PHYSICALLY. LXRBETA ACTIVATION BY GW3965 EXERTED ANALGESIC EFFECTS BY INHIBITING THE NUCLEAR TRANSLOCATION OF NF-KAPPAB, REDUCING THE PHOSPHORYLATION OF MITOGEN-ACTIVATED PROTEIN KINASES (MAPKS) IN ACC, AND DECREASING THE PROMOTED INPUT-OUTPUT AND ENHANCED MEPSC FREQUENCY IN ACC NEURONS AFTER CFA EXPOSURE. IN VITRO EXPERIMENTS CONFIRMED THAT HDAC5 TRIGGERED HISTONE DEACETYLATION ON THE PROMOTER REGION OF LXRBETA, RESULTING IN DOWNREGULATION OF LXRBETA TRANSCRIPTION. CONCLUSION: THESE FINDINGS HIGHLIGHT AN EPIGENETIC MECHANISM UNDERLYING LXRBETA DEFICITS LINKED TO CIP, AND LXRBETA ACTIVATION MAY REPRESENT A POTENTIAL NOVEL TARGET FOR THE TREATMENT OF CIP WITH AN ALTERATION IN INFLAMMATION RESPONSES AND SYNAPTIC TRANSMISSION IN ACC. 2019 14 5063 30 PHOSPHORYLATED HISTONE 3 AT SERINE 10 IDENTIFIES ACTIVATED SPINAL NEURONS AND CONTRIBUTES TO THE DEVELOPMENT OF TISSUE INJURY-ASSOCIATED PAIN. TRANSCRIPTIONAL CHANGES IN SUPERFICIAL SPINAL DORSAL HORN NEURONS (SSDHN) ARE ESSENTIAL IN THE DEVELOPMENT AND MAINTENANCE OF PROLONGED PAIN. EPIGENETIC MECHANISMS INCLUDING POST-TRANSLATIONAL MODIFICATIONS IN HISTONES ARE PIVOTAL IN REGULATING TRANSCRIPTION. HERE, WE REPORT THAT PHOSPHORYLATION OF SERINE 10 (S10) IN HISTONE 3 (H3) SPECIFICALLY OCCURS IN A GROUP OF RAT SSDHN FOLLOWING THE ACTIVATION OF NOCICEPTIVE PRIMARY SENSORY NEURONS BY BURN INJURY, CAPSAICIN APPLICATION OR SUSTAINED ELECTRICAL ACTIVATION OF NOCICEPTIVE PRIMARY SENSORY NERVE FIBRES. IN CONTRAST, BRIEF THERMAL OR MECHANICAL NOCICEPTIVE STIMULI, WHICH FAIL TO INDUCE TISSUE INJURY OR INFLAMMATION, DO NOT PRODUCE THE SAME EFFECT. BLOCKING N-METHYL-D-ASPARTATE RECEPTORS OR ACTIVATION OF EXTRACELLULAR SIGNAL-REGULATED KINASES 1 AND 2, OR BLOCKING OR DELETING THE MITOGEN- AND STRESS-ACTIVATED KINASES 1 AND 2 (MSK1/2), WHICH PHOSPHORYLATE S10 IN H3, INHIBIT UP-REGULATION IN PHOSPHORYLATED S10 IN H3 (P-S10H3) AS WELL AS FOS TRANSCRIPTION, A DOWN-STREAM EFFECT OF P-S10H3. DELETING MSK1/2 ALSO INHIBITS THE DEVELOPMENT OF CARRAGEENAN-INDUCED INFLAMMATORY HEAT HYPERALGESIA IN MICE. WE PROPOSE THAT P-S10H3 IS A NOVEL MARKER FOR NOCICEPTIVE PROCESSING IN SSDHN WITH HIGH RELEVANCE TO TRANSCRIPTIONAL CHANGES AND THE DEVELOPMENT OF PROLONGED PAIN. 2017 15 6301 21 THE PUTATIVE ROLE OF ENVIRONMENTAL MERCURY IN THE PATHOGENESIS AND PATHOPHYSIOLOGY OF AUTISM SPECTRUM DISORDERS AND SUBTYPES. EXPOSURE TO ORGANIC FORMS OF MERCURY HAS THE THEORETICAL CAPACITY TO GENERATE A RANGE OF IMMUNE ABNORMALITIES COUPLED WITH CHRONIC NITRO-OXIDATIVE STRESS SEEN IN CHILDREN WITH AUTISM SPECTRUM DISORDER (ASD). THE PAPER DISCUSSES POSSIBLE MECHANISMS EXPLAINING THE NEUROTOXIC EFFECTS OF MERCURY AND POSSIBLE ASSOCIATIONS BETWEEN MERCURY EXPOSURE AND ASD SUBTYPES. ENVIRONMENTAL MERCURY IS NEUROTOXIC AT DOSES WELL BELOW THE CURRENT REFERENCE LEVELS CONSIDERED TO BE SAFE, WITH EVIDENCE OF NEUROTOXICITY IN CHILDREN EXPOSED TO ENVIRONMENTAL SOURCES INCLUDING FISH CONSUMPTION AND ETHYLMERCURY-CONTAINING VACCINES. POSSIBLE NEUROTOXIC MECHANISMS OF MERCURY INCLUDE DIRECT EFFECTS ON SULFHYDRYL GROUPS, PERICYTES AND CEREBRAL ENDOTHELIAL CELLS, ACCUMULATION WITHIN ASTROCYTES, MICROGLIAL ACTIVATION, INDUCTION OF CHRONIC OXIDATIVE STRESS, ACTIVATION OF IMMUNE-INFLAMMATORY PATHWAYS AND IMPAIRMENT OF MITOCHONDRIAL FUNCTIONING. (EPI-)GENETIC FACTORS WHICH MAY INCREASE SUSCEPTIBILITY TO THE TOXIC EFFECTS OF MERCURY IN ASD INCLUDE THE FOLLOWING: A GREATER PROPENSITY OF MALES TO THE LONG-TERM NEUROTOXIC EFFECTS OF POSTNATAL EXPOSURE AND GENETIC POLYMORPHISMS IN GLUTATHIONE TRANSFERASES AND OTHER GLUTATHIONE-RELATED GENES AND IN SELENOPROTEINS. FURTHERMORE, IMMUNE AND INFLAMMATORY RESPONSES TO IMMUNISATIONS WITH MERCURY-CONTAINING ADJUVANTS ARE STRONGLY INFLUENCED BY POLYMORPHISMS IN THE HUMAN LEUKOCYTE ANTIGEN (HLA) REGION AND BY GENES ENCODING EFFECTOR PROTEINS SUCH AS CYTOKINES AND PATTERN RECOGNITION RECEPTORS. SOME EPIDEMIOLOGICAL STUDIES INVESTIGATING A POSSIBLE RELATIONSHIP BETWEEN HIGH ENVIRONMENTAL EXPOSURE TO METHYLMERCURY AND IMPAIRED NEURODEVELOPMENT HAVE REPORTED A POSITIVE DOSE-DEPENDENT EFFECT. RETROSPECTIVE STUDIES, ON THE OTHER HAND, REPORTED NO RELATIONSHIP BETWEEN A RANGE OF ETHYLMERCURY-CONTAINING VACCINES AND CHRONIC NEUROPATHOLOGY OR ASD. ON THE BASIS OF THESE RESULTS, WE WOULD ARGUE THAT MORE CLINICALLY RELEVANT RESEARCH IS REQUIRED TO EXAMINE WHETHER ENVIRONMENTAL MERCURY IS ASSOCIATED WITH ASD OR SUBTYPES. SPECIFIC RECOMMENDATIONS FOR FUTURE RESEARCH ARE DISCUSSED. 2018 16 4172 35 MELATONIN IMPEDES TET1-DEPENDENT MGLUR5 PROMOTER DEMETHYLATION TO RELIEVE PAIN. MELATONIN (N-ACETYL-5-METHOXYTRYPTAMINE)/MT2 RECEPTOR-DEPENDENT EPIGENETIC MODIFICATION REPRESENTS A NOVEL PATHWAY IN THE TREATMENT OF NEUROPATHIC PAIN. BECAUSE SPINAL TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE 1 (TET1)-DEPENDENT EPIGENETIC DEMETHYLATION HAS RECENTLY BEEN LINKED TO PAIN HYPERSENSITIVITY, WE HYPOTHESIZED THAT MELATONIN/MT2-DEPENDENT ANALGESIA INVOLVES SPINAL TET1-DEPENDENT DEMETHYLATION. HERE, WE SHOWED THAT SPINAL TET1 GENE TRANSFER BY INTRATHECAL DELIVERY OF TET1-ENCODING VECTORS TO NAIVE RATS PRODUCED PROFOUND AND LONG-LASTING NOCICEPTIVE HYPERSENSITIVITY. IN ADDITION, ENHANCED TET1 EXPRESSION, TET1-METABOTROPIC GLUTAMATE RECEPTOR SUBTYPE 5 (MGLUR5) PROMOTER COUPLING, DEMETHYLATION AT THE MGLUR5 PROMOTER, AND MGLUR5 EXPRESSION IN DORSAL HORN NEURONS WERE OBSERVED. RATS SUBJECTED TO SPINAL NERVE LIGATION AND INTRAPLANTAR COMPLETE FREUND'S ADJUVANT INJECTION DISPLAYED TACTILE ALLODYNIA AND BEHAVIORAL HYPERALGESIA ASSOCIATED WITH SIMILAR CHANGES IN THE DORSAL HORN. NOTABLY, INTRATHECAL MELATONIN INJECTION REVERSED THE PROTEIN EXPRESSION, PROTEIN-PROMOTER COUPLING, PROMOTER DEMETHYLATION, AND PAIN HYPERSENSITIVITY INDUCED BY TET1 GENE TRANSFER, SPINAL NERVE LIGATION, AND INTRAPLANTAR COMPLETE FREUND'S ADJUVANT INJECTION. ALL THE EFFECTS CAUSED BY MELATONIN WERE BLOCKED BY PRETREATMENT WITH A MT2 RECEPTOR-SELECTIVE ANTAGONIST. IN CONCLUSION, MELATONIN RELIEVES PAIN BY IMPEDING TET1-DEPENDENT DEMETHYLATION OF MGLUR5 IN DORSAL HORN NEURONS THROUGH THE MT2 RECEPTOR. OUR FINDINGS LINK MELATONIN/MT2 SIGNALING TO TET1-DEPENDENT EPIGENETIC DEMETHYLATION OF NOCICEPTIVE GENES FOR THE FIRST TIME AND SUGGEST MELATONIN AS A PROMISING THERAPY FOR THE TREATMENT OF PAIN. 2017 17 3433 48 HYDROXYMETHYLATION OF MICRORNA-365-3P REGULATES NOCICEPTIVE BEHAVIORS VIA KCNH2. DNA 5-HYDROXYLMETHYLCYTOSINE (5HMC) CATALYZED BY TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE (TET) OCCURS ABUNDANTLY IN NEURONS OF MAMMALS. HOWEVER, THE IN VIVO CAUSAL LINK BETWEEN TET DYSREGULATION AND NOCICEPTIVE MODULATION HAS NOT BEEN ESTABLISHED. HERE, WE FOUND THAT SPINAL TET1 AND TET3 WERE SIGNIFICANTLY INCREASED IN THE MODEL OF FORMALIN-INDUCED ACUTE INFLAMMATORY PAIN, WHICH WAS ACCOMPANIED WITH THE AUGMENT OF GENOME-WIDE 5HMC CONTENT IN SPINAL CORD. KNOCKDOWN OF SPINAL TET1 OR TET3 ALLEVIATED THE FORMALIN-INDUCED NOCICEPTIVE BEHAVIOR AND OVEREXPRESSION OF SPINAL TET1 OR TET3 IN NAIVE MICE PRODUCED PAIN-LIKE BEHAVIOR AS EVIDENCED BY DECREASED THERMAL PAIN THRESHOLD. FURTHERMORE, WE FOUND THAT TET1 OR TET3 REGULATED THE NOCICEPTIVE BEHAVIOR BY TARGETING MICRORNA-365-3P (MIR-365-3P). FORMALIN INCREASED 5HMC IN THE MIR-365-3P PROMOTER, WHICH WAS INHIBITED BY KNOCKDOWN OF TET1 OR TET3 AND MIMICKED BY OVEREXPRESSION OF TET1 OR TET3 IN NAIVE MICE. NOCICEPTIVE BEHAVIOR INDUCED BY FORMALIN OR OVEREXPRESSION OF SPINAL TET1 OR TET3 COULD BE PREVENTED BY DOWNREGULATION OF MIR-365-3P, AND MIMICKED BY OVEREXPRESSION OF SPINAL MIR-365-3P. FINALLY, WE DEMONSTRATED THAT A POTASSIUM CHANNEL, VOLTAGE-GATED EAG-RELATED SUBFAMILY H MEMBER 2 (KCNH2), VALIDATED AS A TARGET OF MIR-365-3P, PLAYED A CRITICAL ROLE IN NOCICEPTIVE MODULATION BY SPINAL TET OR MIR-365-3P. TOGETHER, WE CONCLUDED THAT TET-MEDIATED HYDROXYMETHYLATION OF MIR-365-3P REGULATES NOCICEPTIVE BEHAVIOR VIA KCNH2. SIGNIFICANCE STATEMENT: MOUNTING EVIDENCE INDICATES THAT EPIGENETIC MODIFICATIONS IN THE NOCICEPTIVE PATHWAY CONTRIBUTE TO PAIN PROCESSES AND ANALGESIA RESPONSE. HERE, WE FOUND THAT THE INCREASE OF 5HMC CONTENT MEDIATED BY TET1 OR TET3 IN MIR-365-3P PROMOTER IN THE SPINAL CORD IS INVOLVED IN NOCICEPTIVE MODULATION THROUGH TARGETING A POTASSIUM CHANNEL, KCNH2. OUR STUDY REVEALS A NEW EPIGENETIC MECHANISM UNDERLYING NOCICEPTIVE INFORMATION PROCESSING, WHICH MAY BE A NOVEL TARGET FOR DEVELOPMENT OF ANTINOCICEPTIVE DRUGS. 2016 18 804 33 CENTRAL ENDOTHELIN-1 CONFERS ANALGESIA BY TRIGGERING SPINAL NEURONAL HISTONE DEACETYLASE 5 (HDAC5) NUCLEAR EXCLUSION IN PERIPHERAL NEUROPATHIC PAIN IN MICE. THE RATIONALE OF SPINAL ADMINISTRATION OF ENDOTHELIN-1(ET-1) MEDIATED ANTI-NOCICEPTIVE EFFECT HAS NOT BEEN ELUCIDATED. ET-1 IS REPORTED TO PROMOTE NUCLEAR EFFLUXION OF HISTONE DEACETYLASE 5 (HDAC5) IN MYOCYTES, AND SPINAL HDAC5 IS IMPLICATED IN MODULATION OF PAIN PROCESSING. IN THIS STUDY, WE AIMED TO INVESTIGATE WHETHER CENTRAL ET-1 PLAYS AN ANTI-NOCICEPTIVE ROLE BY FACILITATING SPINAL HDAC5 NUCLEAR SHUTTLING UNDER NEUROPATHIC PAIN. HERE, WE DEMONSTRATE THAT UPREGULATING SPINAL ET-1 ATTENUATED THE NOCICEPTION INDUCED BY PARTIAL SCIATIC NERVE LIGATION SURGERY AND THIS ANALGESIC EFFECT MEDIATED BY ET-1 WAS ATTENUATED BY INTRATHECAL INJECTION OF ENDOTHELIN A RECEPTOR SELECTIVE INHIBITOR (BQ123) OR BY BLOCKING THE EXPORTATION OF NUCLEAR HDAC5 BY ADENO-ASSOCIATED VIRUSES TARGETING NEURONAL HDAC5 (AVV-HDAC5 S259/498A MUTANT). NOTABLY, ET-1 ADMINISTRATION INCREASED SPINAL GLUTAMATE ACID DECARBOXYLASES (GAD65/67) EXPRESSION VIA INITIATING HDAC5 NUCLEAR EXPORTATION AND INCREASED THE ACETYLATION OF HISTONE 3 AT LYSINE 9 (ACETYL-H3K9) IN THE PROMOTOR REGIONS OF SPINAL GAD1 AND GAD2 GENES. THIS WAS REVERSED BY BLOCKING ENDOTHELIN A RECEPTOR FUNCTION OR BY INHIBITING THE SPINAL NEURONAL NUCLEAR EXPORTATION OF HDAC5. THEREFORE, INDUCING SPINAL GABAERGIC NEURONAL HDAC5 NUCLEAR EXPORTATION MAY BE A NOVEL THERAPEUTIC APPROACH FOR MANAGING NEUROPATHIC PAIN. PERSPECTIVE: NEUROPATHIC PAIN IS INTRACTABLE IN A CLINICAL SETTING, AND EPIGENETIC REGULATION IS CONSIDERED TO CONTRIBUTE TO THIS PROCESSING. CHARACTERIZING THE ANTI-NOCICEPTIVE EFFECT OF ET-1 AND INVESTIGATING THE ASSOCIATED EPIGENETIC MECHANISMS IN ANIMAL MODELS MAY LEAD TO THE DEVELOPMENT OF NEW THERAPEUTIC STRATEGIES AND TARGETS FOR TREATING NEUROPATHIC PAIN. 2021 19 2667 31 ESTROGEN AND SEROTONIN ENHANCE STRESS-INDUCED VISCERAL HYPERSENSITIVITY IN FEMALE RATS BY UP-REGULATING BRAIN-DERIVED NEUROTROPHIC FACTOR IN SPINAL CORD. BACKGROUND: WE PREVIOUSLY REPORTED THAT FEMALE OFFSPRING OF DAMS SUBJECTED TO CHRONIC PRENATAL STRESS (CPS) DEVELOP ENHANCED VISCERAL HYPERSENSITIVITY (VHS) FOLLOWING EXPOSURE TO CHRONIC STRESS IN ADULT LIFE THAT IS MEDIATED BY UP-REGULATION OF SPINAL CORD BDNF. THE AIMS OF THIS STUDY WERE TO EXAMINE THE ROLES OF ESTROGEN RECEPTOR ALPHA (ERALPHA) AND AN INCREASE IN SPINAL SEROTONIN SIGNALING IN PROMOTING THIS ENHANCED VHS IN FEMALE RATS AND UP-REGULATION OF SPINAL CORD BDNF TRANSCRIPTION. METHODS: PREGNANT DAMS WERE EXPOSED TO CHRONIC STRESS FROM E11 UNTIL DELIVERY. AT 8 WEEKS, A CHRONIC ADULT STRESS (CAS) PROTOCOL WAS APPLIED FOR NINE DAYS. KEY RESULTS: OVARIECTOMY BEFORE CAS OR TREATMENT WITH LETROZOLE BEFORE AND DURING CAS SIGNIFICANTLY PREVENTED THE DEVELOPMENT OF ENHANCED VHS IN FEMALE CPS+CAS RATS. INTRATHECAL APPLICATION OF ERALPHA SIRNA SIGNIFICANTLY REDUCED VHS, DECREASED LUMBAR-SACRAL SPINAL CORD EXPRESSION OF BOTH ERALPHA AND BDNF, AND REVERSED PRO-TRANSCRIPTIONAL EPIGENETIC MODIFICATIONS AT BDNF PROMOTER LX. CEREBROSPINAL FLUID SEROTONIN LEVELS AND 5HT3A RECEPTOR EXPRESSION IN THE LS SPINAL CORD WERE BOTH SIGNIFICANTLY INCREASED IN FEMALE CPS+CAS RATS. DURING CAS, INTRATHECAL INFUSION OF ALOSETRON SIGNIFICANTLY DECREASED VHS, REDUCED BDNF AND ERALPHA EXPRESSION IN THE LS SPINAL CORD, AND ATTENUATED RNA POL II AND ERALPHA BINDING TO THE BNDF CORE PROMOTER IX. CONCLUSIONS & INFERENCES: SEROTONIN-MEDIATED ACTIVATION OF 5HT3A RECEPTORS IN THE SPINAL CORD DRIVES THE DEVELOPMENT OF ENHANCED FEMALE-SPECIFIC VHS IN OUR TWO HIT CPS+CAS THROUGH UP-REGULATION OF SPINAL CORD ERALPHA. 2021 20 743 32 CANNABINOID TYPE 2 RECEPTOR SYSTEM MODULATES PACLITAXEL-INDUCED MICROGLIAL DYSREGULATION AND CENTRAL SENSITIZATION IN RATS. PACLITAXEL INDUCES MICROGLIAL ACTIVATION AND PRODUCTION OF PROINFLAMMATORY MEDIATORS IN THE DORSAL HORN, WHICH CONTRIBUTE TO THE DEVELOPMENT AND MAINTENANCE OF CENTRAL SENSITIZATION AND PAIN BEHAVIOR. MDA7, 1-([3-BENZYL-3-METHYL-2,3-DIHYDRO-1-BENZOFURAN-6-YL]CARBONYL) PIPERIDINE, IS A NOVEL HIGHLY SELECTIVE CANNABINOID TYPE 2 (CB2) AGONIST. WE TESTED THE HYPOTHESIS THAT ACTIVATION OF CB2 RECEPTOR BY MDA7 MODULATES MICROGLIAL DYSREGULATION, SUPPRESSES THE OVEREXPRESSION OF BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) IN MICROGLIA IN THE DORSAL HORN, AND ATTENUATES THE CENTRAL SENSITIZATION AND PAIN BEHAVIOR INDUCED BY PACLITAXEL. FOR 4 CONSECUTICE DAYS, GROUPS OF RATS RANDOMLY RECEIVED SALINE OR 1.0 MG/KG OF PACLITAXEL DAILY INTRAPERITONEALLY FOR A TOTAL CUMULATIVE DOSE OF 4 MG/KG. MDA7 15 MG/KG INTRAPERITONEALLY OR VEHICLE WERE ADMINISTERED 15 MIN BEFORE ADMINISTERING PACLITAXEL FOR 4 DAYS AND THEN CONTINUED FOR ANOTHER 10 DAYS. BEHAVIORAL AND MOLECULAR STUDIES WERE PERFORMED. PACLITAXEL INDUCED THE EXPRESSION OF CB2 RECEPTORS AND PRODUCTION OF INTERLEUKIN (IL)-6 IN MICROGLIA IN THE DORSAL HORN. MDA7 ATTENUATED THE EXPRESSION OF IL-6 AND PROMOTED THE EXPRESSION OF IL-10. PACLITAXEL INDUCED EPIGENETIC UPREGULATION OF IRF8 AND P2X PURINOCEPTOR 4 (P2X4) IN MICROGLIA AND SUBSEQUENTLY INCREASED THE EXPRESSION OF ALPHA ISOFORM OF CALCIUM/CALMODULIN-DEPENDENT PROTEIN KINASE II (CAMKIIALPHA), TRANSCRIPTIONAL FACTORS P-CREB AND DELTAFOSB, LEADING TO THE OVERPRODUCTION OF BDNF IN MICROGLIA. PACLITAXEL ALSO UPREGULATED THE EXPRESSION OF GLUTAMATE RECEPTOR SUBUNITS GLUR1 AND NR2B, DECREASED THE EXPRESSION OF K(+)-CL(-) COTRANSPORTER, AND INDUCED MECHANICAL ALLODYNIA IN RATS. ALL OF THE AFOREMENTIONED MOLECULAR CHANGES WERE ATTENUATED BY MDA7. OUR DATA SHOW THAT MDA7 ATTENUATED PACLITAXEL-INDUCED MOLECULAR AND BEHAVIORAL CHANGES IN RATS. PERSPECTIVE: THIS STUDY PROVIDES EVIDENCE THAT PACLITAXEL INDUCED MICROGLIA DYSREGULATION AND EPIGENETICALLY UPREGULATED THE MICROGLIAL EXPRESSION OF BDNF, WHICH LED TO SENSITIZATION OF DORSAL HORN NEURONS AND MECHANICAL ALLODYNIA IN RATS. THE CB2 AGONIST MDA7 ALLEVIATED THESE PATHOLOGICAL PROCESSES. MDA7 REPRESENTS AN INNOVATIVE THERAPEUTIC APPROACH FOR TREATMENT OF CHEMOTHERAPY-INDUCED NEUROPATHY. 2019