1 3830 118 INVOLVEMENT OF HISTONE LYSINE CROTONYLATION IN THE REGULATION OF NERVE-INJURY-INDUCED NEUROPATHIC PAIN. HISTONE LYSINE CROTONYLATION (KCR), A NOVEL EPIGENETIC MODIFICATION, IS IMPORTANT IN REGULATING A BROAD SPECTRUM OF BIOLOGICAL PROCESSES AND VARIOUS DISEASES. HOWEVER, WHETHER KCR IS INVOLVED IN NEUROPATHIC PAIN REMAINS TO BE ELUCIDATED. WE FOUND KCR OCCURS IN MACROPHAGES, SENSORY NEURONS, AND SATELLITE GLIAL CELLS OF TRIGEMINAL GANGLIA (TG), NEURONS, ASTROCYTES, AND MICROGLIA OF THE MEDULLA OBLONGATA. KCR IN TG WAS DETECTED MAINLY IN SMALL AND MEDIUM SENSORY NEURONS, TO A LESSER EXTENT IN LARGE NEURONS. PERIPHERAL NERVE INJURY ELEVATED KCR LEVELS IN MACROPHAGES IN THE TRIGEMINAL AND DORSAL ROOT GANGLIA AND MICROGLIA IN THE MEDULLA OBLONGATA BUT REDUCED KCR LEVELS IN SENSORY NEURONS. INHIBITION OF HISTONE CROTONYLTRANSFERASES (P300) BY INTRA-TG OR INTRATHECAL ADMINISTRATION OF C646 SIGNIFICANTLY ALLEVIATED PARTIAL INFRAORBITAL NERVE TRANSECTION (PIONT)- OR SPINAL NERVE LIGATION (SNL)-INDUCED MECHANICAL ALLODYNIA AND THERMAL HYPERALGESIA. INTRA-TG OR INTRATHECAL ADMINISTRATION OF CROTONYL COENZYME A TRILITHIUM SALT TO UPREGULATE KCR DOSE-DEPENDENTLY INDUCED MECHANICAL ALLODYNIA AND THERMAL HYPERALGESIA IN MICE. MECHANISMLY, INHIBITION OF P300 ALLEVIATED PIONT-INDUCED MACROPHAGE ACTIVATION AND REDUCED THE EXPRESSION OF PAIN-RELATED INFLAMMATORY CYTOKINES TNFALPHA, IL1BETA AND CHEMOKINES CCL2 AND CXCL10. CORRESPONDINGLY, EXOGENOUS CROTONYL-COA INDUCED MACROPHAGE ACTIVATION AND THE EXPRESSION OF TNFALPHA, IL1BETA, IL6, CCL2 AND CCL7 IN TG, WHICH C646 CAN REPRESS. THESE FINDINGS SUGGEST THAT HISTONE CROTONYLATION MIGHT BE FUNCTIONALLY INVOLVED IN NEUROPATHIC PAIN AND NEUROINFLAMMATION REGULATION. 2022 2 1084 24 CO-OCCURRENCE OF PROTEIN CROTONYLATION AND 2-HYDROXYISOBUTYRYLATION IN THE PROTEOME OF END-STAGE RENAL DISEASE. END-STAGE RENAL DISEASE (ESRD) IS GRADUALLY BECOMING A MAJOR PUBLIC HEALTHCARE BURDEN WORLDWIDE. POST-TRANSLATIONAL MODIFICATIONS CARRYING EPIGENETIC INFORMATION PLAY A CRUCIAL ROLE IN THE PATHOGENESIS OF MANY CHRONIC DISEASES. WE PERFORMED LYSINE CROTONYLATION (KCR) AND LYSINE 2-HYDROXYISOBUTYRYLATION (KHIB) ANALYSES WITH LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY TO OBTAIN A COMPREHENSIVE PROFILE AND REVEAL THE SPECIFIC PATHOGENESIS OF PERIPHERAL BLOOD MONONUCLEAR CELLS IN ESRD PATIENTS. 218 OVERLAP PROTEINS AMONG DIFFERENTIALLY MODIFIED PROTEINS (DMPS) OF BOTH 2-HYDROXYISOBUTYRYLATION AND CROTONYLATION WERE IDENTIFIED. KEGG ANALYSIS ENRICHED PATHWAYS OF PROTEIN PROCESSING IN ENDOPLASMIC RETICULUM (ER) AND GLYCOLYSIS/GLUCONEOGENESIS WHICH IS CLOSELY RELATED WITH CELL APOPTOSIS. IN BIP, A MASTER REGULATOR IN THE ER, EIGHT SITES WERE IDENTIFIED AS HAVING BOTH KCR AND KHIB MODIFICATIONS. FIVE DIFFERENTIALLY KCR MODIFICATION SITES AND THREE DIFFERENTIALLY KHIB-MODIFIED SITES WERE DETECTED BETWEEN ESRD PATIENTS AND NORMAL CONTROLS. BESIDES BIP, OTHER PROTEINS (GRP94, CNX, CRT, PDIS, GLCII, ERP57, BAP31, HSP70, AND HSP90) HAPPENED BOTH KCR AND KHIB MODIFICATIONS. NINE DMPS HAVING BOTH KCR AND KHIB MODIFICATIONS WERE RELATED TO THE GLYCOLYSIS/GLUCONEOGENESIS PATHWAY CONTAINING TWO KEY REGULATORY ENZYMES OF HEXOKINASE-1 AND PYRUVATE KINASE. THE TWO MOST ABUNDANT DUAL MODIFICATION PROTEINS WERE ENO1 AND PGK1 WITH 15 SITES AND 8 SITES, RESPECTIVELY. LYSINE RESIDUE K228 WITH BOTH KCR AND KHIB MODIFICATIONS IN ENO1 WAS ON ITS SURFACE AND MADE IT ACCESSIBLE FOR P300 MEDIATING DYNAMIC MODIFICATIONS. OVERALL, WE HYPOTHESIZE THAT KCR AND KHIB COMODIFICATIONS MAY INFLUENCE THE NUMBER OF IMMUNOCYTES AND FURTHER INDUCE IMMUNE SENESCENCE IN ESRD PATIENTS THROUGH THE GLYCOLYSIS/GLUCONEOGENESIS PATHWAY AND PROTEIN PROCESSING IN THE ER PROCESS, WHICH MAY BE A POTENTIAL THERAPEUTIC DIRECTION IN THE FUTURE. 2021 3 6051 26 THE CONTRIBUTION OF HISTONE CROTONYLATION TO TISSUE HEALTH AND DISEASE: FOCUS ON KIDNEY HEALTH. ACUTE KIDNEY INJURY (AKI) AND CHRONIC KIDNEY DISEASE (CKD) ARE THE MOST SEVERE CONSEQUENCES OF KIDNEY INJURY. THEY ARE INTERCONNECTED SYNDROMES AS CKD PREDISPOSES TO AKI AND AKI MAY ACCELERATE CKD PROGRESSION. DESPITE THEIR GROWING IMPACT ON THE GLOBAL BURDEN OF DISEASE, THERE IS NO SATISFACTORY TREATMENT FOR AKI AND CURRENT THERAPEUTIC APPROACHES TO CKD REMAIN SUBOPTIMAL. RECENT RESEARCH HAS FOCUSED ON THE THERAPEUTIC TARGET POTENTIAL OF EPIGENETIC REGULATION OF GENE EXPRESSION, INCLUDING NON-CODING RNAS AND THE COVALENT MODIFICATIONS OF HISTONES AND DNA. INDEED, SEVERAL DRUGS TARGETING HISTONE MODIFICATIONS ARE IN CLINICAL USE OR UNDERGOING CLINICAL TRIALS. ACYL-LYSINE HISTONE MODIFICATIONS (E.G. METHYLATION, ACETYLATION, AND CROTONYLATION) HAVE MODULATED EXPERIMENTAL KIDNEY INJURY. MOST RECENTLY, INCREASED HISTONE LYSINE CROTONYLATION (KCR) WAS OBSERVED DURING EXPERIMENTAL AKI AND COULD BE REPRODUCED IN CULTURED TUBULAR CELLS EXPOSED TO INFLAMMATORY STRESS TRIGGERED BY THE CYTOKINE TWEAK. THE DEGREE OF KIDNEY HISTONE CROTONYLATION WAS MODULATED BY CROTONATE AVAILABILITY AND CROTONATE SUPPLEMENTATION PROTECTED FROM NEPHROTOXIC AKI. WE NOW REVIEW THE FUNCTIONAL RELEVANCE OF HISTONE CROTONYLATION IN KIDNEY DISEASE AND OTHER PATHOPHYSIOLOGICAL CONTEXTS, AS WELL AS THE IMPLICATIONS FOR THE DEVELOPMENT OF NOVEL THERAPEUTIC APPROACHES. THESE STUDIES PROVIDE INSIGHTS INTO THE OVERALL ROLE OF HISTONE CROTONYLATION IN HEALTH AND DISEASE. 2020 4 5764 26 SORAFENIB ATTENUATES FIBROTIC HEPATIC INJURY THROUGH MEDIATING LYSINE CROTONYLATION. BACKGROUND: LIVER FIBROSIS IS AN INDEPENDENT CONTRIBUTOR OF CHRONIC LIVER DISEASES, AND REGRESSING LIVER FIBROSIS IS CONSIDERED A POTENTIAL THERAPEUTIC TARGET FOR CHRONIC LIVER DISEASES. WE AIMED TO EXPLORE THE EFFECTS AND MECHANISM OF SORAFENIB IN LIVER FIBROSIS. METHODS: MALE SPRAGUE DAWLEY (SD) RATS WERE SUBJECTED TO SUBCUTANEOUS INJECTION OF CARBON TETRACHLORIDE (CCL(4)) FOR 8 WEEKS TO INDUCE LIVER FIBROSIS AND THEN TREATED WITH SORAFENIB. THE DEGREE OF LIVER FIBROSIS WAS ANALYZED BY HEMATOXYLIN-EOSIN (H&E) STAINING, MASSON STAINING, AND PICROSIRIUS RED (PSR) STAINING. SERUM BIOCHEMICAL INDEXES WERE DETECTED BY FULLY AUTOMATIC BIOCHEMICAL ANALYZER OR ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA). QUANTITATIVE REAL-TIME POLYMERASE CHAIN REACTION (QRT-PCR) WAS PERFORMED TO DETECT THE EXPRESSION OF PRO-FIBROTIC GENES. IMMUNOHISTOCHEMICAL STAINING AND WESTERN BLOTTING WERE CARRIED OUT TO EVALUATE THE LEVELS OF LYSINE CROTONYLATION. RESULTS: LIVER INDEX WAS REDUCED WITH ORAL SORAFENIB IN CCL(4)-INDUCED RATS. SERUM LIVER FUNCTION (ALANINE AMINOTRANSFERASE (ALT), ASPARTATE AMINOTRANSFERASE (AST), AND TOTAL BILIRUBIN (TBIL)) AND FIBROSIS INDICATORS (TYPE III PROCOLLAGEN (PC-III), HYALURONIC ACID (HA), AND LAMININ (LN)) WERE ATTENUATED WITH SORAFENIB TREATMENT. SORAFENIB IMPROVED THE HEPATIC STRUCTURE AND FIBROTIC PROGRESSION. THE EXPRESSION OF FIBROSIS-RELATED GENES WAS REMARKELY REDUCED WITH SORAFENIB TREATMENT. MEANWHILE, SORAFENIB INHIBITED ALPHA-SMA AND COLLAGEN I CUMULATION INDUCED BY CCL(4) INJECTION. BESIDES, PROTEIN LYSINE CROTONYLATION ESPECIALLY THE CROTONYLATED H2BK12 (H2BK12CR) AND CROTONYLATED H3K18 (H3K18CR) WERE REVERSED BY SORAFENIB, WHICH WERE DECREASED IN RESPONSE TO CCL(4) TREATMENT. SPEARMAN CORRELATION ANALYSIS SHOWN LYSINE CROTONYLATION EXPRESSION WAS NEGATIVELY CORRELATED WITH SERUM FIBROTIC INDICATORS. CONVERSELY, CROTONYLATION-REGULATED ENZYMES, WHICH NEGATIVELY REGULATE PROTEIN CROTONYLATION, WERE INCREASED IN RESPONSE TO CCL(4) TREATMENT, WHILE SORAFENIB REDUCED THEIR EXPRESSION. CONCLUSION: SORAFENIB EXERTS SIGNIFICANT ANTI-FIBROTIC EFFECTS THROUGH MEDIATING CROTONYLATION-REGULATED ENZYMES AND PROTEIN CROTONYLATION IN FIBROTIC RATS. 2022 5 863 26 CHROMODOMAIN Y-LIKE PROTEIN-MEDIATED HISTONE CROTONYLATION REGULATES STRESS-INDUCED DEPRESSIVE BEHAVIORS. BACKGROUND: MAJOR DEPRESSIVE DISORDER IS A PREVALENT AND LIFE-THREATENING ILLNESS IN MODERN SOCIETY. THE SUSCEPTIBILITY TO MAJOR DEPRESSIVE DISORDER IS PROFOUNDLY INFLUENCED BY ENVIRONMENTAL FACTORS, SUCH AS STRESSFUL LIFESTYLE OR TRAUMATIC EVENTS, WHICH COULD IMPOSE MALADAPTIVE TRANSCRIPTIONAL PROGRAM THROUGH EPIGENETIC REGULATION. HOWEVER, THE UNDERLYING MOLECULAR MECHANISMS REMAIN ELUSIVE. HERE, WE EXAMINED THE ROLE OF HISTONE CROTONYLATION, A NOVEL TYPE OF HISTONE MODIFICATION, AND CHROMODOMAIN Y-LIKE PROTEIN (CDYL), A CROTONYL-COENZYME A HYDRATASE AND HISTONE METHYLLYSINE READER, IN THIS PROCESS. METHODS: WE USED CHRONIC SOCIAL DEFEAT STRESS AND MICRODEFEAT STRESS TO EXAMINE THE DEPRESSIVE BEHAVIORS. IN ADDITION, WE COMBINED PROCEDURES THAT DIAGNOSE BEHAVIORAL STRATEGY IN MALE MICE WITH HISTONE EXTRACTION, VIRAL-MEDIATED CDYL MANIPULATIONS, RNA SEQUENCING, CHROMATIN IMMUNOPRECIPITATION, WESTERN BLOT, AND MESSENGER RNA QUANTIFICATION. RESULTS: THE RESULTS INDICATE THAT STRESS-SUSCEPTIBLE RODENTS EXHIBIT LOWER LEVELS OF HISTONE CROTONYLATION IN THE MEDIAL PREFRONTAL CORTEX CONCURRENT WITH SELECTIVE UPREGULATION OF CDYL. OVEREXPRESSION OF CDYL IN THE PRELIMBIC CORTEX, A SUBREGION OF THE MEDIAL PREFRONTAL CORTEX, INCREASES MICRODEFEAT-INDUCED SOCIAL AVOIDANCE BEHAVIORS AND ANHEDONIA IN MICE. CONVERSELY, KNOCKDOWN OF CDYL IN THE PRELIMBIC CORTEX PREVENTS CHRONIC SOCIAL DEFEAT STRESS-INDUCED DEPRESSION-LIKE BEHAVIORS. MECHANISTICALLY, WE SHOW THAT CDYL INHIBITS STRUCTURAL SYNAPTIC PLASTICITY MAINLY BY TRANSCRIPTIONAL REPRESSION OF NEUROPEPTIDE VGF NERVE GROWTH FACTOR INDUCIBLE, AND THIS ACTIVITY IS DEPENDENT ON ITS DUAL EFFECT ON HISTONE CROTONYLATION AND H3K27 TRIMETHYLATION ON THE VGF PROMOTER. CONCLUSIONS: OUR RESULTS DEMONSTRATE THAT CDYL-MEDIATED HISTONE CROTONYLATION PLAYS A CRITICAL ROLE IN REGULATING STRESS-INDUCED DEPRESSION, PROVIDING A POTENTIAL THERAPEUTIC TARGET FOR MAJOR DEPRESSIVE DISORDER. 2019 6 4906 37 P300 EXERTS AN EPIGENETIC ROLE IN CHRONIC NEUROPATHIC PAIN THROUGH ITS ACETYLTRANSFERASE ACTIVITY IN RATS FOLLOWING CHRONIC CONSTRICTION INJURY (CCI). BACKGROUND: NEUROPATHIC PAIN IS DETRIMENTAL TO HUMAN HEALTH; HOWEVER, ITS PATHOGENESIS STILL REMAINS LARGELY UNKNOWN. OVEREXPRESSION OF PAIN-ASSOCIATED GENES AND INCREASED NOCICEPTIVE SOMATO-SENSITIVITY ARE WELL OBSERVED IN NEUROPATHIC PAIN. THE IMPORTANCE OF EPIGENETIC MECHANISMS IN REGULATING THE EXPRESSION OF PRO- OR ANTI-NOCICEPTIVE GENES HAS BEEN REVEALED BY STUDIES RECENTLY, AND WE HYPOTHESIZE THAT THE TRANSCRIPTIONAL COACTIVATOR AND THE HISTONE ACETYLTRANSFERASE E1A BINDING PROTEIN P300 (P300), AS A PART OF THE EPIGENETIC MECHANISMS OF GENE REGULATION, MAY BE INVOLVED IN THE PATHOGENESIS OF NEUROPATHIC PAIN INDUCED BY CHRONIC CONSTRICTION INJURY (CCI). TO TEST THIS HYPOTHESIS, TWO DIFFERENT APPROACHES WERE USED IN THIS STUDY: (I) DOWN-REGULATING P300 WITH SPECIFIC SMALL HAIRPIN RNA (SHRNA) AND (II) CHEMICAL INHIBITION OF P300 ACETYLTRANSFERASE ACTIVITY BY A SMALL MOLECULE INHIBITOR, C646. RESULTS: USING THE CCI RAT MODEL, WE FOUND THAT THE P300 EXPRESSION WAS INCREASED IN THE LUMBAR SPINAL CORD ON DAY 14 AFTER CCI. THE TREATMENT WITH INTRATHECAL P300 SHRNA REVERSED CCI-INDUCED MECHANICAL ALLODYNIA AND THERMAL HYPERALGESIA, AND SUPPRESSED THE EXPRESSION OF CYCLOOXYGENASE-2 (COX-2), A NEUROPATHIC PAIN-ASSOCIATED FACTOR. FURTHERMORE, C646, AN INHIBITOR OF P300 ACETYLTRANSFERASE, ALSO ATTENUATED MECHANICAL ALLODYNIA AND THERMAL HYPERALGESIA, ACCOMPANIED BY A SUPPRESSED COX-2 EXPRESSION, IN THE SPINAL CORD. CONCLUSIONS: THE RESULTS SUGGEST THAT, THROUGH ITS ACETYLTRANSFERASE ACTIVITY IN THE SPINAL CORD AFTER CCI, P300 EPIGENETICALLY PLAYS AN IMPORTANT ROLE IN NEUROPATHIC PAIN. INHIBITING P300, USING INTERFERING RNA OR C646, MAY BE A PROMISING APPROACH TO THE DEVELOPMENT OF NEW NEUROPATHIC PAIN THERAPIES. 2012 7 2751 34 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 8 532 35 ASTROCYTIC C-JUN N-TERMINAL KINASE-HISTONE DEACETYLASE-2 CASCADE CONTRIBUTES TO GLUTAMATE TRANSPORTER-1 DECREASE AND MECHANICAL ALLODYNIA FOLLOWING PERIPHERAL NERVE INJURY IN RATS. DECREASE OF GLUTAMATE TRANSPORTER-1 (GLT-1) IN THE SPINAL DORSAL HORN AFTER NERVE INJURY INDUCES ENHANCED EXCITATORY TRANSMISSION AND CAUSES PERSISTENT PAIN. HISTONE DEACETYLASES (HDACS)-CATALYZED DEACETYLATION MIGHT CONTRIBUTE TO THE DECREASE OF GLT-1, WHILE THE DETAILED MECHANISMS HAVE YET TO BE FULLY ELABORATED. SPINAL NERVE LIGATION (SNL) INDUCED SIGNIFICANT INCREASES OF HDAC2 AND DECREASES OF GLT-1 IN SPINAL ASTROCYTES. INTRATHECAL INFUSION OF THE HDAC2 INHIBITORS ATTENUATED THE DECREASE OF GLT-1 AND ENHANCED PHOSPHORYLATION OF GLUTAMATE RECEPTORS. GLT-1 AND PHOSPHORYLATED C-JUN N-TERMINAL KINASE (JNK) WERE HIGHLY COLOCALIZED IN THE SPINAL CORD, AND A LARGE NUMBER OF PJNK POSITIVE CELLS WERE HDAC2 POSITIVE. INTRATHECALLY INFUSION OF THE JNK INHIBITOR SP600125 SIGNIFICANTLY INHIBITED SNL-INDUCED UPREGULATION OF HDAC2. SNL-INDUCED HDAC2 UP-REGULATION COULD BE INHIBITED BY THE NEUTRALIZING ANTI-TUMOR NECROSIS FACTOR-ALPHA (TNF-ALPHA) BINDING PROTEIN ETANERCEPT OR THE MICROGLIAL INHIBITOR MINOCYCLINE. IN CULTURED ASTROCYTES, TNF-ALPHA INDUCED ENHANCED PHOSPHORYLATION OF JNK AND A SIGNIFICANT INCREASE OF HDAC2, AS WELL AS A REMARKABLE DECREASE OF GLT-1, WHICH COULD BE PREVENTED BY SP600125 OR THE HDAC2 SPECIFIC INHIBITOR CAY10683. OUR DATA SUGGEST THAT ASTROCYTIC JNK-HDAC2 CASCADE CONTRIBUTES TO GLT-1 DECREASE AND MECHANICAL ALLODYNIA FOLLOWING PERIPHERAL NERVE INJURY. NEUROIMMUNE ACTIVATION AFTER PERIPHERAL NERVE INJURY COULD INDUCE EPIGENETIC MODIFICATION CHANGES IN ASTROCYTES AND CONTRIBUTE TO CHRONIC PAIN MAINTENANCE. 2021 9 742 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 10 6172 37 THE HDAC1/C-JUN COMPLEX IS ESSENTIAL IN THE PROMOTION OF NERVE INJURY-INDUCED NEUROPATHIC PAIN THROUGH JNK SIGNALING. HISTONE DEACETYLASE INHIBITORS (HDACIS) INTERFERE WITH THE EPIGENETIC PROCESS OF HISTONE ACETYLATION AND ARE KNOWN TO HAVE ANALGESIC PROPERTIES IN MODELS OF CHRONIC INFLAMMATORY PAIN. ADMINISTRATION OF A SELECTIVE HDAC1 INHIBITOR (LG325) IN SNI-SUBJECTED MICE SIGNIFICANTLY ATTENUATED BEHAVIOR RELATED TO INJURY-INDUCED PAIN. UNDERSTANDING THE HDAC1 PATHWAY IN EPIGENETIC REGULATION OF PATHOLOGICAL PAIN IS OF GREAT MEDICAL RELEVANCE. SPARED NERVE INJURY (SNI) MICE SHOWED A SIGNIFICANT INCREASE IN THE HDAC1 PROTEIN LEVELS WITHIN SPINAL CORD IN COINCIDENCE WITH THE NOCICEPTIVE PHENOTYPE AT 1 AND 3 WEEKS AFTER NERVE INJURY. NO VARIATION IN HDAC3, DNMT3A, ACH3, MBD3 AND MECP2 LEVELS WAS DETECTED. INCREASED EXPRESSION OF HDAC1 IS ACCOMPANIED BY ACTIVATION OF THE JNK-C-JUN SIGNALING PATHWAY. A ROBUST SPINAL JNK-1 OVERPHOSPHORYLATION WAS OBSERVED POST NERVE-INJURY ALONG WITH A SELECTIVE JNK-DEPENDENT INCREASE IN P-C-JUN AND HDAC1 PROTEIN LEVELS. CO-IMMUNOPRECIPITATION EXPERIMENTS SHOWED THE PRESENCE OF A HETERODIMERIC COMPLEX BETWEEN HDAC1 AND C-JUN IN SNI MICE INDICATING THAT THESE TRANSCRIPTION FACTORS CAN ACT TOGETHER TO REGULATE TRANSCRIPTION THROUGH HETERODIMERIZATION. STIMULATION OF C-JUN PHOSPHORYLATION WAS PREVENTED BY THE SELECTIVE HDAC1 INHIBITOR LG325. WE FOUND THAT HDAC1 WAS ASSOCIATED WITH C-JUN IN NUCLEI OF SPINAL DORSAL HORN ASTROCYTES EXPRESSING JNK. ON THE OTHER HAND, THE PRESENCE OF HDAC1 AND C-JUN INTERACTION WAS NOT DETECTED IN CONTROL MICE. THESE FINDINGS PROVIDE NEW INSIGHTS INTO THE MECHANISMS UNDERLYING THE ANTI-NOCICEPTIVE ACTIVITY OF HDAC INHIBITORS. TAKEN TOGETHER, THESE DATA SUPPORT A ROLE FOR HISTONE DEACETYLASE IN THE EMERGENCE OF NEUROPATHIC PAIN. 2018 11 5574 33 ROLE OF MICRORNA-143 IN NERVE INJURY-INDUCED UPREGULATION OF DNMT3A EXPRESSION IN PRIMARY SENSORY NEURONS. PERIPHERAL NERVE INJURY INCREASED THE EXPRESSION OF THE DNA METHYLTRANSFERASE 3A (DNMT3A) MRNA AND ITS ENCODING DNMT3A PROTEIN IN INJURED DORSAL ROOT GANGLIA (DRG). THIS INCREASE IS CONSIDERED AS AN ENDOGENOUS INSTIGATOR IN NEUROPATHIC PAIN GENESIS THROUGH EPIGENETIC SILENCING OF PAIN-ASSOCIATED GENES (SUCH AS OPRM1) IN INJURED DRG. HOWEVER, HOW DRG DNMT3A IS INCREASED FOLLOWING PERIPHERAL NERVE INJURY IS STILL ELUSIVE. WE REPORTED HERE THAT PERIPHERAL NERVE INJURY CAUSED BY THE FIFTH SPINAL NERVE LIGATION (SNL) DOWNREGULATED MICRORNA (MIR)-143 EXPRESSION IN INJURED DRG. THIS DOWNREGULATION WAS REQUIRED FOR SNL-INDUCED DRG DNMT3A INCREASE AS RESCUING MIR-143 DOWNREGULATION THROUGH MICROINJECTION OF MIR-143 MIMICS INTO INJURED DRG BLOCKED THE SNL-INDUCED INCREASE IN DNMT3A AND RESTORED THE SNL-INDUCED DECREASES IN OPRM1 MRNA AND ITS ENCODING MU OPIOID RECEPTOR (MOR) IN INJURED DRG, IMPAIRED SPINAL CORD CENTRAL SENSITIZATION AND NEUROPATHIC PAIN, AND IMPROVED MORPHINE ANALGESIC EFFECTS FOLLOWING SNL. MIMICKING SNL-INDUCED DRG MIR-143 DOWNREGULATION THROUGH DRG MICROINJECTION OF MIR143 INHIBITORS IN NAIVE RATS INCREASED THE EXPRESSION OF DNMT3A AND REDUCED THE EXPRESSION OF OPRM1 MRNA AND MOR IN INJECTED DRG AND PRODUCED NEUROPATHIC PAIN-LIKE SYMPTOMS. THESE FINDINGS SUGGEST THAT MIR-143 IS A NEGATIVE REGULATOR IN DNMT3A EXPRESSION IN THE DRG UNDER NEUROPATHIC PAIN CONDITIONS AND MAY BE A POTENTIAL TARGET FOR THERAPEUTIC MANAGEMENT OF NEUROPATHIC PAIN. 2017 12 1654 38 DORSAL ROOT GANGLIA COACTIVATOR-ASSOCIATED ARGININE METHYLTRANSFERASE 1 CONTRIBUTES TO PERIPHERAL NERVE INJURY-INDUCED PAIN HYPERSENSITIVITIES. NEUROPATHIC PAIN IS ASSOCIATED WITH GENE EXPRESSION CHANGES WITHIN THE DORSAL ROOT GANGLION (DRG) AFTER PERIPHERAL NERVE INJURY, WHICH INVOLVES EPIGENETIC MECHANISMS. COACTIVATOR-ASSOCIATED ARGININE METHYLTRANSFERASE 1 (CARM1), AN EPIGENETIC ACTIVATOR, REGULATES GENE TRANSCRIPTIONAL ACTIVITY BY PROTEIN POSTTRANSLATIONAL MODIFICATIONS. HOWEVER, WHETHER CARM1 PLAYS AN ESSENTIAL ROLE IN THE DEVELOPMENT AND MAINTENANCE OF NEUROPATHIC PAIN IS UNKNOWN. WE REPORT HERE THAT PERIPHERAL NERVE INJURY INDUCED THE UPREGULATION OF THE MRNA AND PROTEIN EXPRESSION OF CARM1 IN THE INJURED DRG, AND BLOCKING ITS EXPRESSION THROUGH SMALL INTERFERING RNA (SIRNA) IN THE INJURED DRG ATTENUATED THE DEVELOPMENT AND MAINTENANCE OF NEUROPATHIC PAIN. FURTHERMORE, PHARMACOLOGICAL INHIBITION OF CARM1 MITIGATED PERIPHERAL NERVE INJURY-INDUCED MECHANICAL ALLODYNIA AND THERMAL HYPERALGESIA. GIVEN THAT CARM1 INHIBITION OR KNOCKDOWN ATTENUATED THE INDUCTION AND MAINTENANCE OF NEUROPATHIC PAIN AFTER PERIPHERAL NERVE INJURY, OUR FINDINGS SUGGEST THAT CARM1 MAY SERVE AS A PROMISING THERAPEUTIC TARGET FOR NEUROPATHIC PAIN TREATMENT IN CLINICAL APPLICATIONS. 2018 13 3869 30 JNK1 REGULATES HISTONE ACETYLATION IN TRIGEMINAL NEURONS FOLLOWING CHEMICAL STIMULATION. TRIGEMINAL NERVE FIBERS IN NASAL AND ORAL CAVITIES ARE SENSITIVE TO VARIOUS ENVIRONMENTAL HAZARDOUS STIMULI, WHICH TRIGGER MANY NEUROTOXIC PROBLEMS SUCH AS CHRONIC MIGRAINE HEADACHE AND TRIGEMINAL IRRITATED DISORDERS. HOWEVER, THE ROLE OF JNK KINASE CASCADE AND ITS EPIGENETIC MODULATION OF HISTONE REMODELING IN TRIGEMINAL GANGLION (TG) NEURONS ACTIVATED BY ENVIRONMENTAL NEUROTOXINS REMAINS UNKNOWN. HERE WE INVESTIGATED THE ROLE OF JNK/C-JUN CASCADE IN THE REGULATION OF ACETYLATION OF H3 HISTONE IN TG NEURONS FOLLOWING IN VITRO STIMULATION BY A NEURO-INFLAMMATORY AGENT, MUSTARD OIL (MO). WE FOUND THAT MO STIMULATION ELICITED JNK/C-JUN PATHWAY SIGNIFICANTLY BY ENHANCING PHOSPHO-JNK1, PHOSPHO-C-JUN EXPRESSION, AND C-JUN ACTIVITY, WHICH WERE CORRELATED WITH AN ELEVATED ACETYLATED H3 HISTONE IN TG NEURONS. HOWEVER, INCREASES IN PHOSPHO-C-JUN AND C-JUN ACTIVITY WERE SIGNIFICANTLY BLOCKED BY A JNK INHIBITOR, SP600125. WE ALSO FOUND THAT ALTERED H3 HISTONE REMODELING, ASSESSED BY H3 ACETYLATION IN TRIGGERED TG NEURONS, WAS REDUCED BY SP600125. THE STUDY SUGGESTS THAT THE ACTIVATED JNK SIGNALING IN REGULATION OF HISTONE REMODELING MAY CONTRIBUTE TO NEURO-EPIGENTIC CHANGES IN PERIPHERAL SENSORY NEURONS FOLLOWING ENVIRONMENTAL NEUROTOXIC EXPOSURE. 2008 14 2785 38 EZH2 REGULATES SPINAL NEUROINFLAMMATION IN RATS WITH NEUROPATHIC PAIN. ALTERATION IN GENE EXPRESSION ALONG THE PAIN SIGNALING PATHWAY IS A KEY MECHANISM CONTRIBUTING TO THE GENESIS OF NEUROPATHIC PAIN. ACCUMULATING STUDIES HAVE SHOWN THAT EPIGENETIC REGULATION PLAYS A CRUCIAL ROLE IN NOCICEPTIVE PROCESS IN THE SPINAL DORSAL HORN. IN THIS PRESENT STUDY, WE INVESTIGATED THE ROLE OF ENHANCER OF ZESTE HOMOLOG-2 (EZH2), A SUBUNIT OF THE POLYCOMB REPRESSIVE COMPLEX 2, IN THE SPINAL DORSAL HORN IN THE GENESIS OF NEUROPATHIC PAIN IN RATS INDUCED BY PARTIAL SCIATIC NERVE LIGATION. EZH2 IS A HISTONE METHYLTRANSFERASE, WHICH CATALYZES THE METHYLATION OF HISTONE H3 ON K27 (H3K27), RESULTING IN GENE SILENCING. WE FOUND THAT LEVELS OF EZH2 AND TRI-METHYLATED H3K27 (H3K27TM) IN THE SPINAL DORSAL HORN WERE INCREASED IN RATS WITH NEUROPATHIC PAIN ON DAY 3 AND DAY 10 POST NERVE INJURIES. EZH2 WAS PREDOMINANTLY EXPRESSED IN NEURONS IN THE SPINAL DORSAL HORN UNDER NORMAL CONDITIONS. THE NUMBER OF NEURONS WITH EZH2 EXPRESSION WAS INCREASED AFTER NERVE INJURY. MORE STRIKINGLY, NERVE INJURY DRASTICALLY INCREASED THE NUMBER OF MICROGLIA WITH EZH2 EXPRESSION BY MORE THAN SEVENFOLD. INTRATHECAL INJECTION OF THE EZH2 INHIBITOR ATTENUATED THE DEVELOPMENT AND MAINTENANCE OF MECHANICAL AND THERMAL HYPERALGESIA IN RATS WITH NERVE INJURY. SUCH ANALGESIC EFFECTS WERE CONCURRENTLY ASSOCIATED WITH THE REDUCED LEVELS OF EZH2, H3K27TM, IBA1, GFAP, TNF-ALPHA, IL-1BETA, AND MCP-1 IN THE SPINAL DORSAL HORN IN RATS WITH NERVE INJURY. OUR RESULTS HIGHLY SUGGEST THAT TARGETING THE EZH2 SIGNALING PATHWAY COULD BE AN EFFECTIVE APPROACH FOR THE MANAGEMENT OF NEUROPATHIC PAIN. 2017 15 5925 27 TARGETING EPIGENETIC DNA AND HISTONE MODIFICATIONS TO TREAT KIDNEY DISEASE. EPIGENETICS REFERS TO HERITABLE CHANGES IN GENE EXPRESSION PATTERNS NOT CAUSED BY AN ALTERED NUCLEOTIDE SEQUENCE, AND INCLUDES NON-CODING RNAS AND COVALENT MODIFICATIONS OF DNA AND HISTONES. THIS REVIEW FOCUSES ON FUNCTIONAL EVIDENCE FOR THE INVOLVEMENT OF DNA AND HISTONE EPIGENETIC MODIFICATIONS IN THE PATHOGENESIS OF KIDNEY DISEASE AND THE POTENTIAL THERAPEUTIC IMPLICATIONS. THERE IS EVIDENCE OF ACTIVATION OF EPIGENETIC REGULATORY MECHANISMS IN ACUTE KIDNEY INJURY (AKI), CHRONIC KIDNEY DISEASE (CKD) AND THE AKI-TO-CKD TRANSITION OF DIVERSE AETIOLOGIES, INCLUDING ISCHAEMIA-REPERFUSION INJURY, NEPHROTOXICITY, URETERAL OBSTRUCTION, DIABETES, GLOMERULONEPHRITIS AND POLYCYSTIC KIDNEY DISEASE. A BENEFICIAL IN VIVO EFFECT OVER PRECLINICAL KIDNEY INJURY HAS BEEN REPORTED FOR DRUGS THAT DECREASE DNA METHYLATION BY EITHER INHIBITING DNA METHYLATION (E.G. 5-AZACYTIDINE AND DECITABINE) OR ACTIVATING DNA DEMETHYLATION (E.G. HYDRALAZINE), DECREASE HISTONE METHYLATION BY INHIBITING HISTONE METHYLTRANSFERASES, INCREASE HISTONE ACETYLATION BY INHIBITING HISTONE DEACETYLASES (HDACS, E.G. VALPROIC ACID, VORINOSTAT, ENTINOSTAT), INCREASE HISTONE CROTONYLATION (CROTONATE) OR INTERFERE WITH HISTONE MODIFICATION READERS [E.G. INHIBITS OF BROMODOMAIN AND EXTRA-TERMINAL PROTEINS (BET)]. MOST PRECLINICAL STUDIES ADDRESSED CKD OR THE AKI-TO-CKD TRANSITION. CROTONATE ADMINISTRATION PROTECTED FROM NEPHROTOXIC AKI, BUT EVIDENCE IS CONFLICTING ON DNA METHYLATION INHIBITORS FOR PRECLINICAL AKI. SEVERAL DRUGS TARGETING EPIGENETIC REGULATORS ARE IN CLINICAL DEVELOPMENT OR USE, MOST OF THEM FOR MALIGNANCY. THE BET INHIBITOR APABETALONE IS IN PHASE 3 TRIALS FOR ATHEROSCLEROSIS, KIDNEY FUNCTION BEING A SECONDARY ENDPOINT, BUT NEPHROTOXICITY WAS REPORTED FOR DNA AND HDAC INHIBITORS. WHILE RESEARCH INTO EPIGENETIC MODULATORS MAY PROVIDE NOVEL THERAPIES FOR KIDNEY DISEASE, CAUTION SHOULD BE EXERCISED BASED ON THE CLINICAL NEPHROTOXICITY OF SOME DRUGS. 2018 16 4698 29 NFATC2-DEPENDENT EPIGENETIC DOWNREGULATION OF THE TSC2/BECLIN-1 PATHWAY IS INVOLVED IN NEUROPATHIC PAIN INDUCED BY OXALIPLATIN. NEUROPATHIC PAIN IS A COMMON DOSE-LIMITING SIDE EFFECT OF OXALIPLATIN, WHICH HAMPERS THE EFFECTIVE TREATMENT OF TUMORS. HERE, WE FOUND THAT UPREGULATION OF TRANSCRIPTION FACTOR NFATC2 DECREASED THE EXPRESSION OF BECLIN-1, A CRITICAL MOLECULE IN AUTOPHAGY, IN THE SPINAL DORSAL HORN, AND CONTRIBUTED TO NEUROPATHIC PAIN FOLLOWING OXALIPLATIN TREATMENT. MEANWHILE, MANIPULATING AUTOPHAGY LEVELS BY INTRATHECAL INJECTION OF RAPAMYCIN (RAPA) OR 3-METHYLADENINE (3-MA) DIFFERENTIALLY ALTERED MECHANICAL ALLODYNIA IN OXALIPLATIN-TREATED OR NAIVE RATS. UTILIZING CHROMATIN IMMUNOPRECIPITATION-SEQUENCING (CHIP-SEQ) ASSAY COMBINED WITH BIOINFORMATICS ANALYSIS, WE FOUND THAT NFATC2 NEGATIVELY REGULATED THE TRANSCRIPTION OF TUBEROUS SCLEROSIS COMPLEX PROTEIN 2 (TSC2), WHICH CONTRIBUTED TO THE OXALIPLATIN-INDUCED BECLIN-1 DOWNREGULATION. FURTHER ASSAYS REVEALED THAT NFATC2 REGULATED HISTONE H4 ACETYLATION AND METHYLATION IN THE TSC2 PROMOTER SITE 1 IN RATS' DORSAL HORNS WITH OXALIPLATIN TREATMENT. THESE RESULTS SUGGESTED THAT NFATC2 MEDIATED THE EPIGENETIC DOWNREGULATION OF THE TSC2/BECLIN-1 AUTOPHAGY PATHWAY AND CONTRIBUTED TO OXALIPLATIN-INDUCED MECHANICAL ALLODYNIA, WHICH PROVIDED A NEW THERAPEUTIC INSIGHT FOR CHEMOTHERAPY-INDUCED NEUROPATHIC PAIN. 2023 17 3832 29 INVOLVEMENT OF SPINAL SIRT1 IN DEVELOPMENT OF CHRONIC CONSTRICTION INJURY INDUCED NEUROPATHIC PAIN IN RATS. IT IS KNOWN THAT THE EPIGENETIC PROCESS OF HISTONE ACETYLATION IS INVOLVED IN THE NEUROPATHIC PAIN. THE AIM OF THIS STUDY WAS TO DETERMINE WHETHER SIRTUIN TYPE 1 (SIRT1), AN NAD(+) DEPENDENT DEACETYLASE, AFFECTED ALLODYNIA AND HYPERALGESIA IN NEUROPATHIC PAIN. THE NEUROPATHIC PAIN MODEL WAS ESTABLISHED BY LIGATURE OF THE RIGHT SCIATIC NERVE TO INDUCE CHRONIC CONSTRICTION INJURY (CCI) IN RATS. HISTONE ACETYLTRANSFERASE (HAT) ACTIVITY WAS INCREASED AND, AND HISTONE DEACETYLASE (HDAC) ACTIVITY WAS DECLINED IN TISSUE OF THE SPINAL DORSA HORN IN CCI RATES BY MEANS OF ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA). THE PERSISTENT HYPERALGESIA AND ALLODYNIA CAUSED BY CCI WERE ASSOCIATED WITH DOWNREGULATION OF SIRT1 AND UPREGULATION OF ACETYLATED-H3 (AC-H3) IN TISSUE OF THE SPINAL CORD BY WESTERN BLOT ASSAY, WHICH WAS REVERSED AFTER INTRATHECAL INJECTION OF SIRT1 AGONIST SRT1720. SRT1720 TREATMENT ACHIEVED ANALGESIC THROUGH INHIBITING THE ACETYLATION OF NUCLEAR FACTOR KAPPA B (NF-KAPPAB) AND BLOCKING THE RELEASES OF THE INFLAMMATORY FACTORS INCLUDING TUMOR NECROSIS FACTOR-ALPHA (TNF-ALPHA) AND INTERLEUKIN (IL)-6 BY MEANS OF WESTERN BLOT AND REAL-TIME QUANTITATIVE PCR (RT-PCR), RESPECTIVELY. TAKEN TOGETHER, THESE DATA SUGGEST THAT SIRT1 IN THE SPINAL CORD PLAYS AN IMPORTANT ROLE IN THE NEUROPATHIC PAIN IN THE RAT MODEL. 2018 18 2476 36 EPIGENETIC UPREGULATION OF CCL2 AND CCL3 VIA HISTONE MODIFICATIONS IN INFILTRATING MACROPHAGES AFTER PERIPHERAL NERVE INJURY. TO GAIN INSIGHT INTO THE EPIGENETIC REGULATION OF CC-CHEMOKINE LIGAND (CCL) 2 AND CCL3, KEY PLAYERS IN THE PERIPHERAL SENSITIZATION LEADING TO NEUROPATHIC PAIN, WE EXAMINED THE RELATIONSHIP BETWEEN HISTONE H3 MODIFICATION AND THE UPREGULATION OF THESE MOLECULES USING A MOUSE MODEL OF NEUROPATHIC PAIN AFTER PARTIAL SCIATIC NERVE LIGATION (PSL). WE FOUND THAT CIRCUITING BONE MARROW (BM)-DERIVED MACROPHAGES INFILTRATED INTO THE INJURED SCIATIC NERVE (SCN) USING ENHANCED GREEN FLUORESCENT PROTEIN CHIMERIC MICE. THE MRNA LEVELS OF CCL2, CCL3 AND THEIR RECEPTORS (CCR2 AND CCR1/CCR5, RESPECTIVELY) WERE INCREASED IN THE INJURED SCN. CHROMATIN IMMUNOPRECIPITATION ASSAY REVEALED THAT LEVELS OF LYSINE 9-ACETYLATED HISTONE H3 (H3K9AC) AND LYSINE 4-TRIMETHYLATED H3 (H3K4ME(3)) IN THE PROMOTER REGIONS OF THE CCL2 AND CCL3 GENES WERE INCREASED IN THE INJURED SCN AFTER PSL, INDICATING THE ENHANCEMENT OF GENE EXPRESSION. IMMUNOREACTIVITY FOR H3K9AC AND H3K4ME(3) WAS LOCALIZED IN THE NUCLEI OF INFILTRATING BM-DERIVED CELLS AND CCL-EXPRESSING CELLS IN THE INJURED SCN. WE OBSERVED H3K9AC AND H3K4ME(3) MAINLY IN THE NUCLEI OF RECRUITED MACROPHAGES ON DAY 7 AFTER PSL. FURTHERMORE, UPREGULATION OF CCLS AND CCRS WERE SUPPRESSED BY HISTONE ACETYLTRANSFERASE INHIBITOR, ANACARDIC ACID. TAKEN TOGETHER, OUR FINDINGS DEMONSTRATE THAT CCL2 AND CCL3 ARE UPREGULATED IN THE INJURED PERIPHERAL NERVE THROUGH EPIGENETIC HISTONE MODIFICATION IN INFILTRATING IMMUNE CELLS SUCH AS MACROPHAGES. THESE CHEMOKINE CASCADES MAY SUBSEQUENTLY ELICIT CHRONIC NEUROINFLAMMATION FOLLOWING NERVE INJURY. 2013 19 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 20 5851 41 SUBEROYLANILIDE HYDROXAMIC ACID TRIGGERS AUTOPHAGY BY INFLUENCING THE MTOR PATHWAY IN THE SPINAL DORSAL HORN IN A RAT NEUROPATHIC PAIN MODEL. HISTONE ACETYLATION LEVELS CAN BE UPREGULATED BY TREATING CELLS WITH HISTONE DEACETYLASE INHIBITORS (HDACIS), WHICH CAN INDUCE AUTOPHAGY. AUTOPHAGY FLUX IN THE SPINAL CORD OF RATS FOLLOWING THE LEFT FIFTH LUMBER SPINAL NERVE LIGATION (SNL) IS INVOLVED IN THE PROGRESSION OF NEUROPATHIC PAIN. SUBEROYLANILIDE HYDROXAMIC ACID (SAHA), ONE OF THE HDACIS CAN INTERFERE WITH THE EPIGENETIC PROCESS OF HISTONE ACETYLATION, WHICH HAS BEEN SHOWN TO EASE NEUROPATHIC PAIN. RECENT RESEARCH SUGGEST THAT SAHA CAN STIMULATE AUTOPHAGY VIA THE MAMMALIAN TARGET OF RAPAMYCIN (MTOR) PATHWAY IN SOME TYPES OF CANCER CELLS. HOWEVER, LITTLE IS KNOWN ABOUT THE ROLE OF SAHA AND AUTOPHAGY IN NEUROPATHIC PAIN AFTER NERVE INJURY. IN THE PRESENT STUDY, WE AIM TO INVESTIGATE AUTOPHAGY FLUX AND THE ROLE OF THE MTOR PATHWAY ON SPINAL CELLS AUTOPHAGY ACTIVATION IN NEUROPATHIC PAIN INDUCED BY SNL IN RATS THAT RECEIVED SAHA TREATMENT. AUTOPHAGY-RELATED PROTEINS AND MTOR OR ITS ACTIVE FORM WERE ASSESSED BY USING WESTERN BLOT, IMMUNOHISTOCHEMISTRY, DOUBLE IMMUNOFLUORESCENCE STAINING AND TRANSMISSION ELECTRON MICROSCOPY (TEM). WE FOUND THAT SAHA DECREASED THE PAW MECHANICAL WITHDRAWAL THRESHOLD (PMWT) OF THE LOWER COMPARED WITH SNL. AUTOPHAGY FLUX WAS MAINLY DISRUPTED IN THE ASTROCYTES AND NEURONAL CELLS OF THE SPINAL CORD DORSAL HORN ON POSTSURGICAL DAY 28 AND WAS REVERSED BY DAILY INTRATHECAL INJECTION OF SAHA (N = 100 NMOL/DAY OR N = 200 NMOL/DAY). SAHA ALSO DECREASED MTOR AND PHOSPHORYLATED MTOR (P-MTOR) EXPRESSION, ESPECIALLY P-MTOR EXPRESSION IN ASTROCYTES AND NEURONAL CELLS OF THE SPINAL DORSAL HORN. THESE RESULTS SUGGEST THAT SAHA ATTENUATES NEUROPATHIC PAIN AND CONTRIBUTES TO AUTOPHAGY FLUX IN ASTROCYTES AND NEURONAL CELLS OF THE SPINAL DORSAL HORN VIA THE MTOR SIGNALING PATHWAY. 2019