1 897 118 CHRONIC EXERCISE TRAINING ACTIVATES HISTONE TURNOVER IN MOUSE SKELETAL MUSCLE FIBERS. EPIGENETIC REGULATION OF SKELETAL MUSCLE ADAPTATION TO EXERCISE IS A RECENT TOPIC FOR WHICH THERE IS LIMITED INFORMATION. THIS STUDY INVESTIGATED WHETHER EXERCISE TRAINING ACTIVATES HISTONE TURNOVER IN THE SKELETAL MUSCLE FIBERS OF MICE. EXPERIMENTS USING A TETRACYCLINE-INDUCIBLE H2B-GFP EXPRESSION MODEL DEMONSTRATED THAT 4 WEEKS OF RUNNING TRAINING, BUT NOT 2 WEEKS OF TRAINING, SIGNIFICANTLY PROMOTED THE INCORPORATION OF H2B-GFP INTO NUCLEOSOMES AND THE DISSOCIATION OF HISTONE H3.3 AT BOTH TRANSCRIPTIONALLY UPREGULATED AND NONRESPONSIVE LOCI. MUSCLE-SPECIFIC PGC-1ALPHA-B-OVEREXPRESSING MICE CROSSED WITH H2B-GFP MICE SHOWED A SLIGHT INCREASE IN H2B-GFP INCORPORATION AT TRANSCRIPTIONALLY ACTIVE LOCI, BUT NOT IN THE DISSOCIATION OF H3.3 FROM NUCLEOSOMES. GENE EXPRESSION RESPONSES TO A SINGLE BOUT OF RUNNING WERE SIGNIFICANTLY ENHANCED IN 4-WEEK TRAINED MICE WHEN COMPARED WITH THOSE IN 2-WEEK TRAINED MICE. THE MOST DRASTIC INCREASE IN THE GENE RESPONSE WAS FOUND IN THE EXPRESSION OF HSPA1A AND HSPA1B, IN WHICH THE MAGNITUDE OF UPREGULATION IN RESPONSE TO RUNNING WAS SIGNIFICANTLY ENHANCED FROM 8-FOLD IN 2 WEEK TRAINED MICE TO 97- AND 121-FOLD IN 4 WEEK TRAINED MICE, RESPECTIVELY. IT WAS ALSO FOUND THAT THE HSP70 LEVEL INCREASED DURING THE TRAINING PERIOD. IN A MYONUCLEAR IMMUNOHISTOCHEMICAL ANALYSIS OF CHROMATIN REMODELERS, WE FURTHER FOUND THAT THE LEVEL OF SPT16, AN H2A-H2B-SPECIFIC CHAPERONE, WAS UPREGULATED AFTER RUNNING TRAINING. THESE RESULTS REVEALED THAT 4 WEEKS OF RUNNING TRAINING ACTIVATED HISTONE TURNOVER IN SKELETAL MUSCLE FIBERS. THEY ALSO SUGGESTED THAT HISTONE TURNOVER LED TO LOOSENING OF THE NUCLEOSOMES AND ENHANCED GENE RESPONSES TO EXERCISE. 2021 2 4096 14 MATRIX METALLOPROTEINASES, NEURAL EXTRACELLULAR MATRIX, AND CENTRAL NERVOUS SYSTEM PATHOLOGY. THE FUNCTIONALITY AND STABILITY OF THE CENTRAL NERVOUS SYSTEM (CNS) PABULUM, CALLED NEURAL EXTRACELLULAR MATRIX (NECM), IS PARAMOUNT FOR THE MAINTENANCE OF A HEALTHY NETWORK. THE LOOSENING OR THE DAMAGE OF THE SCAFFOLD DISRUPTS SYNAPTIC TRANSMISSION WITH THE CONSEQUENT IMBALANCE OF THE NEUROTRANSMITTERS, REACTIVE CELLS INVASION, ASTROCYTOSIS, NEW MATRIX DEPOSITION, DIGESTION OF THE PREVIOUS STRUCTURE AND ULTIMATELY, MALADAPTIVE PLASTICITY WITH THE LOSS OF NEURONAL VIABILITY. NECM IS CONSTANTLY AFFECTED BY CNS DISORDERS, PARTICULARLY IN CHRONIC MODIFYING SUCH AS NEURODEGENERATIVE DISEASE, OR IN ACUTE/SUBACUTE WITH CHRONIC SEQUELAE, LIKE CEREBROVASCULAR AND INFLAMMATORY PATHOLOGY. MATRIX METALLOPROTEINASES (MMPS) ARE THE MAIN INTERFERING AGENT OF NECM, GUIDING THE BALANCE OF DEGRADATION AND NEW DEPOSITION OF PROTEINS SUCH AS PROTEOGLYCANS AND GLYCOPROTEINS, OR GLYCOSAMINOGLYCANS, SUCH AS HYALURONIC ACID. ACTIVATION OF THESE ENZYMES IS MODULATED BY THEIR PHYSIOLOGIC INHIBITORS, THE TISSUE INHIBITORS OF MMPS OR VIA OTHER PROTEASES INHIBITORS, AS WELL AS GENETIC OR EPIGENETIC UP- OR DOWNREGULATION THROUGH MOLECULAR INTERACTION OR RECEPTOR ACTIVATION. THE APPROPRIATE UNDERSTANDING OF THE PATHWAYS UNDERLYING NECM MODIFICATIONS IN CNS PATHOLOGY IS PROBABLY ONE OF THE PIVOTAL FUTURE DIRECTIONS TO IDENTIFY THE HEALTHY BRAIN NETWORK AND SUBSEQUENTLY DESIGN NEW THERAPIES TO INTERFERE WITH THE PROGRESSION OF THE CNS DISEASE AND EVENTUALLY FIND APPROPRIATE THERAPIES. 2017 3 5990 31 TGF-BETA1 PROMOTES EXPRESSION OF FIBROSIS-RELATED GENES THROUGH THE INDUCTION OF HISTONE VARIANT H3.3 AND HISTONE CHAPERONE HIRA. RENAL FIBROSIS IS A HISTOLOGICAL MANIFESTATION THAT OCCURS IN ALMOST EVERY TYPE OF CHRONIC KIDNEY DISEASE. HISTONE VARIANT H3.3 AND ITS CHAPERONE, HISTONE CELL CYCLE REGULATION DEFECTIVE HOMOLOG A (HIRA), SERVE AS EPIGENETIC MARKS THAT REGULATE TRANSCRIPTIONAL ACTIVITY. IN THIS STUDY, WE ASSESSED THE ROLES OF HISTONE H3.3 AND HIRA IN UNILATERAL URETERAL-OBSTRUCTION (UUO) MICE. IN UUO MICE, THE LEVELS OF HISTONE H3.3 AND HIRA WERE SIGNIFICANTLY UPREGULATED IN THE KIDNEYS. THESE UPREGULATED LEVELS WERE DECREASED BY A TGF-BETA1 NEUTRALIZING ANTIBODY. TGF-BETA1 INDUCED HISTONE H3.3 AND HIRA EXPRESSION IN VITRO VIA A SMAD3-DEPENDENT PATHWAY IN NORMAL RAT KIDNEY (NRK)-52E CELLS. ADDITIONALLY, KNOCKDOWN OF HIRA EXPRESSION DECREASED HISTONE H3.3 EXPRESSION AND FIBROGENESIS IN NRK-52E CELLS AFTER TGF-BETA1 STIMULATION. CHROMATIN IMMUNOPRECIPITATION ANALYSIS REVEALED THAT PROMOTERS OF FIBROSIS-RELATED GENES WERE IMMUNOPRECIPITATED WITH BOTH HISTONE H3.3 AND HIRA IN NRK-52E CELLS. LASTLY, IN HUMAN KIDNEY BIOPSIES FROM PATIENTS DIAGNOSED WITH IGA NEPHROPATHY, HISTONE H3.3 AND HIRA IMMUNOSTAINING CORRELATED POSITIVELY WITH AREAS OF FIBROSIS AND ESTIMATED GLOMERULAR FILTRATION RATE. IN CONCLUSION, TGF-BETA1 INDUCES EXPRESSION OF HISTONE H3.3 AND HIRA, WHICH REGULATES EXPRESSION OF FIBROSIS-RELATED GENES. 2018 4 4163 32 MECP2 REPRESSION OF G9A IN REGULATION OF PAIN AND MORPHINE REWARD. OPIOIDS ARE COMMONLY USED FOR PAIN RELIEF, BUT THEIR STRONG REWARDING EFFECTS DRIVE OPIOID MISUSE AND ABUSE. HOW PAIN AFFECTS THE LIABILITY OF OPIOID ABUSE IS UNKNOWN AT PRESENT. IN THIS STUDY, WE IDENTIFIED AN EPIGENETIC REGULATING CASCADE ACTIVATED BY BOTH PAIN AND THE OPIOID MORPHINE. BOTH PERSISTENT PAIN AND REPEATED MORPHINE UPREGULATED THE TRANSCRIPTIONAL REGULATOR MECP2 IN MOUSE CENTRAL NUCLEUS OF THE AMYGDALA (CEA). CHROMATIN IMMUNOPRECIPITATION ANALYSIS REVEALED THAT MECP2 BOUND TO AND REPRESSED THE TRANSCRIPTIONAL REPRESSOR HISTONE DIMETHYLTRANSFERASE G9A, REDUCING G9A-CATALYZED REPRESSIVE MARK H3K9ME2 IN CEA. REPRESSION OF G9A ACTIVITY INCREASED EXPRESSION OF BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF). BEHAVIORALLY, PERSISTENT INFLAMMATORY PAIN INCREASED THE SENSITIVITY TO ACQUIRING MORPHINE-INDUCED, REWARD-RELATED BEHAVIOR OF CONDITIONED PLACE PREFERENCE IN MICE. LOCAL VIRAL VECTOR-MEDIATED MECP2 OVEREXPRESSION, CRE-INDUCED G9A KNOCKDOWN, AND CEA APPLICATION OF BDNF MIMICKED, WHEREAS MECP2 KNOCKDOWN INHIBITED, THE PAIN EFFECT. THESE RESULTS SUGGEST THAT MECP2 DIRECTLY REPRESSES G9A AS A SHARED MECHANISM IN CENTRAL AMYGDALA FOR REGULATION OF EMOTIONAL RESPONSES TO PAIN AND OPIOID REWARD, AND FOR THEIR BEHAVIORAL INTERACTION. 2014 5 5018 31 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 6 3176 45 H3.3 BARCODING OF NUCLEUS ACCUMBENS TRANSCRIPTIONAL ACTIVITY IDENTIFIES NOVEL MOLECULAR CASCADES ASSOCIATED WITH COCAINE SELF-ADMINISTRATION IN MICE. ALTHOUGH NUMEROUS EPIGENETIC MODIFICATIONS HAVE BEEN ASSOCIATED WITH ADDICTION, LITTLE WORK HAS EXPLORED THE TURNOVER OF HISTONE VARIANTS. UNIQUELY, THE H3.3 VARIANT INCORPORATES STABLY AND PREFERENTIALLY INTO CHROMATIN INDEPENDENTLY OF DNA REPLICATION AT ACTIVE SITES OF TRANSCRIPTION AND TRANSCRIPTION FACTOR BINDING. THUS, GENOMIC REGIONS ASSOCIATED WITH H3.3-CONTAINING NUCLEOSOMES ARE PARTICULARLY LIKELY TO BE INVOLVED IN PLASTICITY, SUCH AS FOLLOWING REPEATED COCAINE EXPOSURE. A RECENTLY DEVELOPED MOUSE LINE EXPRESSING A NEURON-SPECIFIC HEMAGGLUTININ (HA)-TAGGED H3.3 PROTEIN WAS USED TO TRACK TRANSCRIPTIONALLY ACTIVE SITES CUMULATIVELY ACROSS 19 D OF COCAINE SELF-ADMINISTRATION. RNA-SEQ AND H3.3-HA CHIP-SEQ ANALYSES WERE PERFORMED ON NACC TISSUE COLLECTED FOLLOWING COCAINE OR FOOD SELF-ADMINISTRATION IN MALE MICE. RNA SEQUENCING REVEALED FIVE GENES UPREGULATED IN COCAINE RELATIVE TO FOOD SELF-ADMINISTERING MICE: FOSB, NPAS4, VGF, NPTX2, AND PMEPA1, WHICH REFLECT KNOWN AND NOVEL COCAINE PLASTICITY-ASSOCIATED GENES. SUBSEQUENT CHIP-SEQ ANALYSIS CONFIRMED INCREASED H3.3 AGGREGATION AT FOUR OF THESE FIVE LOCI, THUS VALIDATING H3.3 INSERTION AS A MARKER OF ENHANCED COCAINE-INDUCED TRANSCRIPTION. FURTHER MOTIF RECOGNITION ANALYSIS OF THE CHIP-SEQ DATA SHOWED THAT COCAINE-ASSOCIATED DIFFERENTIAL H3.3 ACCUMULATION CORRELATED WITH THE PRESENCE OF SEVERAL TRANSCRIPTION FACTOR BINDING MOTIFS, INCLUDING RBPJ1, EGR1, AND SOX4, SUGGESTING THAT THESE ARE POTENTIALLY IMPORTANT REGULATORS OF MOLECULAR CASCADES ASSOCIATED WITH COCAINE-INDUCED NEURONAL PLASTICITY. ADDITIONAL ONTOLOGICAL ANALYSIS REVEALED DIFFERENTIAL H3.3 ACCUMULATION MAINLY NEAR GENES INVOLVED IN NEURONAL DIFFERENTIATION AND DENDRITE FORMATION. THESE RESULTS ESTABLISH THE H3.3-HA TRANSGENIC MOUSE LINE AS A COMPELLING MOLECULAR BARCODING TOOL TO IDENTIFY THE CUMULATIVE EFFECTS OF LONG-TERM ENVIRONMENTAL PERTURBATIONS, SUCH AS EXPOSURE TO DRUGS OF ABUSE.SIGNIFICANCE STATEMENT HISTONE H3.3 IS A CORE HISTONE VARIANT THAT IS STABLY INCORPORATED AT ACTIVE SITES OF TRANSCRIPTION. WE USED A TAGGED VERSION OF H3.3 EXPRESSED EXCLUSIVELY IN NEURONS TO DELINEATE ACTIVE TRANSCRIPTION SITES FOLLOWING EXTENDED COCAINE SELF-ADMINISTRATION IN MICE. THIS APPROACH REVEALED THE CUMULATIVE LIST OF GENES EXPRESSED IN RESPONSE TO COCAINE TAKING OVER THE COURSE OF SEVERAL WEEKS. WE COMBINED THIS TECHNIQUE WITH RNA SEQUENCING OF TISSUE COLLECTED FROM THE SAME ANIMALS 24 H AFTER THE LAST COCAINE EXPOSURE. COMPARING THESE DATASETS PROVIDED A FULL PICTURE OF GENES THAT RESPOND TO CHRONIC COCAINE EXPOSURE IN NACC NEURONS. THESE STUDIES REVEALED NOVEL TRANSCRIPTION FACTORS THAT ARE LIKELY INVOLVED IN COCAINE-INDUCED PLASTICITY AND ADDICTION-LIKE BEHAVIORS. 2019 7 2751 25 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 4511 27 MU OPIOID RECEPTOR-TRIGGERED NOTCH-1 ACTIVATION CONTRIBUTES TO MORPHINE TOLERANCE: ROLE OF NEURON-GLIA COMMUNICATION. THE DEVELOPMENT OF ANALGESIC TOLERANCE TO OPIOIDS IS AN IMPORTANT LIMITATION IN THE MANAGEMENT OF CHRONIC PAIN. SPINAL CORD GLIAL CELL ACTIVATION APPEARS TO PLAY A PIVOTAL ROLE IN THE DEVELOPMENT AND MAINTENANCE OF OPIOID TOLERANCE, INDICATING THE PRESENCE OF AN OPIOID-INDUCED NEURONAL-GLIAL INTERACTION; HOWEVER, HOW OPIOIDS DRIVE THIS CROSS-TALK IS STILL ELUSIVE. IN SEARCH OF TREATMENTS TO ATTENUATE MORPHINE ANALGESIC TOLERANCE, OUR RESEARCH FOCUSED ON THE ROLE OF NOTCH SIGNALING PATHWAY, ONE OF THE MOST IMPORTANT MECHANISMS OF CELL-TO-CELL INTERACTIONS, IN THE SPINAL DORSAL HORN AFTER MORPHINE REPEATED EXPOSURE AND WHETHER NOTCH INHIBITION ATTENUATES MORPHINE ANALGESIC TOLERANCE. DOUBLE IMMUNOFLUORESCENCE EXPERIMENTS ON SPINAL SECTIONS FROM MORPHINE-TOLERANT MICE SHOWED A NEURONAL LOCALIZATION OF NOTCH-1 RECEPTOR WHEREAS THE NOTCH LIGAND JAGGED WAS LOCALIZED ON NEIGHBORING ASTROCYTES. MORPHINE-INDUCED MU OPIOID RECEPTOR (MOR) STIMULATION TRIGGERED NOTCH-1 SIGNALING ACTIVATION AND THIS EVENT WAS MEDIATED BY ASTROCYTE JNK ACTIVATION. NOTCH-1 ACTIVATION SELECTIVELY REDUCED THE EXPRESSION OF HISTONE DEACETYLASE (HDAC)-1, RESULTING IN AN OVERPHOSPHORYLATION OF PKC AND ERK, KINASES INVOLVED IN MOR PHOSPHORYLATION AND INTERNALIZATION AFTER REPEATED MORPHINE EXPOSURE. NOTCH-1 SIGNALING INHIBITION, THROUGH INTRATHECAL ADMINISTRATION OF THE GAMMA-SECRETASE INHIBITOR, DAPT, COUNTERACTED PKC AND ERK OVERPHOSPHORYLATION, MOR INTERNALIZATION, AND ANALGESIC TOLERANCE. CONVERSELY, THE HDAC-1 INHIBITOR, LG325, FURTHER AGGRAVATED MOR INTERNALIZATION, PKC OVERPHOSPHORYLATION, AND ANALGESIC TOLERANCE.OUR FINDINGS IMPLICATE THE MOR-TRIGGERED NOTCH-1 SIGNALING IN PROMOTING MOR INTERNALIZATION AND MORPHINE ANALGESIC TOLERANCE BY EPIGENETIC REGULATION MECHANISMS. THESE DATA SUGGEST THAT NOTCH-1 INHIBITORS COULD REPRESENT AN INNOVATIVE THERAPEUTIC PERSPECTIVE FOR THE MANAGEMENT OF OPIOID TOLERANCE IN CHRONIC PAIN THERAPY. 2020 9 1018 19 CIRCFHIT MODULATES GABAERGIC SYNAPTIC TRANSMISSION VIA REGULATING THE PARENTAL GENE FHIT EXPRESSION IN THE SPINAL DORSAL HORN IN A RAT MODEL OF NEUROPATHIC PAIN. EFFECTIVE TREATMENTS FOR NEUROPATHIC PAIN ARE LACKING DUE TO OUR LIMITED UNDERSTANDING OF THE MECHANISMS. THE CIRCRNAS ARE MAINLY ENRICHED IN THE CENTRAL NERVOUS SYSTEM. HOWEVER, THEIR FUNCTION IN VARIOUS PHYSIOLOGICAL AND PATHOLOGICAL CONDITIONS HAVE YET TO BE DETERMINED. HERE, WE IDENTIFIED CIRCFHIT, AN EXON-INTRON CIRCRNA EXPRESSED IN GABAERGIC NEURONS, WHICH REDUCED THE INHIBITORY SYNAPTIC TRANSMISSION IN THE SPINAL DORSAL HORN TO MEDIATE SPARED NERVE INJURY-INDUCED NEUROPATHIC PAIN. MOREOVER, WE FOUND THAT CIRCFHIT DECREASED THE EXPRESSION OF GAD65 AND INDUCED HYPEREXCITATION IN NK1R(+) NEURONS BY PROMOTING THE EXPRESSION OF ITS PARENTAL GENE FHIT IN CIS. MECHANISTICALLY, CIRCFHIT WAS DIRECTLY BOUND TO THE INTRONIC REGION OF FHIT, AND FORMED A CIRCFHIT/HNRNPK COMPLEX TO PROMOTE POL II PHOSPHORYLATION AND H2B MONOUBIQUITINATION BY RECRUITING CDK9 AND RNF40 TO THE FHIT INTRON. IN SUMMARY, WE REVEALED THAT THE EXON-INTRON CIRCFHIT CONTRIBUTES TO GABAERGIC NEURON-MEDIATED NK1R(+) NEURONAL HYPEREXCITATION AND NEUROPATHIC PAIN VIA REGULATING FHIT IN CIS. 2023 10 3830 23 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 11 6567 26 TRANSLATOMIC RESPONSE OF RETINAL MULLER GLIA TO ACUTE AND CHRONIC STRESS. ANALYSIS OF RETINA CELL TYPE-SPECIFIC EPIGENETIC AND TRANSCRIPTOMIC SIGNATURES IS CRUCIAL TO UNDERSTANDING THE PATHOPHYSIOLOGY OF RETINAL DEGENERATIONS SUCH AS AGE-RELATED MACULAR DEGENERATION (AMD) AND DELINEATING CELL AUTONOMOUS AND CELL-NON-AUTONOMOUS MECHANISMS. WE HAVE DISCOVERED THAT ALDH1L1 IS SPECIFICALLY EXPRESSED IN THE MAJOR MACROGLIA OF THE RETINA, MULLER GLIA, AND, UNLIKE THE BRAIN, IS NOT EXPRESSED IN RETINAL ASTROCYTES. THIS ALLOWS USE OF ALDH1L1 CRE DRIVERS AND NUCLEAR TAGGING AND TRANSLATING RIBOSOME AFFINITY PURIFICATION (NUTRAP) CONSTRUCTS FOR TEMPORALLY CONTROLLED LABELING AND PAIRED ANALYSIS OF MULLER GLIA EPIGENOMES AND TRANSLATOMES. AS VALIDATED THROUGH A VARIETY OF APPROACHES, THE ALDH1L1CRE/ERT2-NUTRAP MODEL PROVIDES MULLER GLIA SPECIFIC TRANSLATOMIC AND EPIGENOMIC PROFILES WITHOUT THE NEED TO ISOLATE WHOLE CELLS. APPLICATION OF THIS APPROACH TO MODELS OF ACUTE INJURY (OPTIC NERVE CRUSH) AND CHRONIC STRESS (AGING) UNCOVERED FEW COMMON MULLER GLIA-SPECIFIC TRANSCRIPTOME CHANGES IN INFLAMMATORY PATHWAYS, AND MOSTLY DIFFERENTIAL SIGNATURES FOR EACH STIMULUS. THE EXPRESSION OF MEMBERS OF THE IL-6 AND INTEGRIN-LINKED KINASE SIGNALING PATHWAYS WAS ENHANCED IN MULLER GLIA IN RESPONSE TO OPTIC NERVE CRUSH BUT NOT AGING. UNIQUE CHANGES IN NEUROINFLAMMATION AND FIBROSIS SIGNALING PATHWAYS WERE OBSERVED IN RESPONSE TO AGING BUT NOT WITH OPTIC NERVE CRUSH. THE ALDH1L1CRE/ERT2-NUTRAP MODEL ALLOWS FOCUSED MOLECULAR ANALYSES OF A SINGLE, MINORITY CELL TYPE WITHIN THE RETINA, PROVIDING MORE SUBSTANTIAL EFFECT SIZES THAN WHOLE TISSUE ANALYSES. THE NUTRAP MODEL, NUCLEIC ACID ISOLATION, AND VALIDATION APPROACHES PRESENTED HERE CAN BE APPLIED TO ANY RETINA CELL TYPE FOR WHICH A CELL TYPE-SPECIFIC CRE IS AVAILABLE. 2022 12 5021 34 PERSISTENT PAIN MAINTAINS MORPHINE-SEEKING BEHAVIOR AFTER MORPHINE WITHDRAWAL THROUGH REDUCED MECP2 REPRESSION OF GLUA1 IN RAT CENTRAL AMYGDALA. AS LONG-TERM OPIOIDS ARE INCREASINGLY USED FOR CONTROL OF CHRONIC PAIN, HOW PAIN AFFECTS THE REWARDING EFFECT OF OPIOIDS AND HENCE RISK OF PRESCRIPTION OPIOID MISUSE AND ABUSE REMAINS A HEALTHCARE CONCERN AND A CHALLENGING ISSUE IN CURRENT PAIN MANAGEMENT. IN THIS STUDY, USING A RAT MODEL OF MORPHINE SELF-ADMINISTRATION, WE INVESTIGATED THE MOLECULAR MECHANISMS UNDERLYING THE IMPACT OF PAIN ON OPERANT BEHAVIOR OF MORPHINE INTAKE AND MORPHINE SEEKING BEFORE AND AFTER MORPHINE WITHDRAWAL. WE FOUND THAT RATS WITH PERSISTENT PAIN CONSUMED A SIMILAR AMOUNT OF DAILY MORPHINE TO THAT IN CONTROL RATS WITHOUT PAIN, BUT MAINTAINED THEIR LEVEL-PRESSING BEHAVIOR OF MORPHINE SEEKING AFTER ABSTINENCE OF MORPHINE AT 0.2 MG/KG, WHEREAS THIS BEHAVIOR WAS GRADUALLY DIMINISHED IN CONTROL RATS. IN THE CENTRAL NUCLEUS OF AMYGDALA (CEA), A LIMBIC STRUCTURE CRITICALLY INVOLVED IN THE AFFECTIVE DIMENSION OF PAIN, PROTEINS OF GLUA1 SUBUNITS OF GLUTAMATE AMPA RECEPTORS WERE UPREGULATED DURING MORPHINE WITHDRAWAL, AND VIRAL KNOCKDOWN OF CEA GLUA1 ELIMINATED THE MORPHINE-SEEKING BEHAVIOR IN WITHDRAWN RATS OF THE PAIN GROUP. CHROMATIN IMMUNOPRECIPITATION ANALYSIS REVEALED THAT THE METHYL CPG-BINDING PROTEIN 2 (MECP2) WAS ENRICHED IN THE PROMOTER REGION OF GRIA1 ENCODING GLUA1 AND THIS ENRICHMENT WAS SIGNIFICANTLY ATTENUATED IN WITHDRAWN RATS OF THE PAIN GROUP. FURTHERMORE, VIRAL OVEREXPRESSION OF CEA MECP2 REPRESSED THE GLUA1 LEVEL AND ELIMINATED THE MAINTENANCE OF MORPHINE-SEEKING BEHAVIOR AFTER MORPHINE WITHDRAWAL. THESE RESULTS SUGGEST DIRECT MECP2 REPRESSION OF GLUA1 FUNCTION AS A LIKELY MECHANISM FOR MORPHINE-SEEKING BEHAVIOR MAINTAINED BY LONG-LASTING AFFECTIVE PAIN AFTER MORPHINE WITHDRAWAL. 2015 13 2358 30 EPIGENETIC REGULATION OF RAC1 INDUCES SYNAPTIC REMODELING IN STRESS DISORDERS AND DEPRESSION. DEPRESSION INDUCES STRUCTURAL AND FUNCTIONAL SYNAPTIC PLASTICITY IN BRAIN REWARD CIRCUITS, ALTHOUGH THE MECHANISMS PROMOTING THESE CHANGES AND THEIR RELEVANCE TO BEHAVIORAL OUTCOMES ARE UNKNOWN. TRANSCRIPTIONAL PROFILING OF THE NUCLEUS ACCUMBENS (NAC) FOR RHO GTPASE-RELATED GENES, WHICH ARE KNOWN REGULATORS OF SYNAPTIC STRUCTURE, REVEALED A SUSTAINED REDUCTION IN RAS-RELATED C3 BOTULINUM TOXIN SUBSTRATE 1 (RAC1) EXPRESSION AFTER CHRONIC SOCIAL DEFEAT STRESS. THIS WAS ASSOCIATED WITH A REPRESSIVE CHROMATIN STATE SURROUNDING THE PROXIMAL PROMOTER OF RAC1. INHIBITION OF CLASS 1 HISTONE DEACETYLASES (HDACS) WITH MS-275 RESCUED BOTH THE DECREASE IN RAC1 TRANSCRIPTION AFTER SOCIAL DEFEAT STRESS AND DEPRESSION-RELATED BEHAVIOR, SUCH AS SOCIAL AVOIDANCE. WE FOUND A SIMILAR REPRESSIVE CHROMATIN STATE SURROUNDING THE RAC1 PROMOTER IN THE NAC OF SUBJECTS WITH DEPRESSION, WHICH CORRESPONDED WITH REDUCED RAC1 TRANSCRIPTION. VIRAL-MEDIATED REDUCTION OF RAC1 EXPRESSION OR INHIBITION OF RAC1 ACTIVITY IN THE NAC INCREASES SOCIAL DEFEAT-INDUCED SOCIAL AVOIDANCE AND ANHEDONIA IN MICE. CHRONIC SOCIAL DEFEAT STRESS INDUCES THE FORMATION OF STUBBY EXCITATORY SPINES THROUGH A RAC1-DEPENDENT MECHANISM INVOLVING THE REDISTRIBUTION OF SYNAPTIC COFILIN, AN ACTIN-SEVERING PROTEIN DOWNSTREAM OF RAC1. OVEREXPRESSION OF CONSTITUTIVELY ACTIVE RAC1 IN THE NAC OF MICE AFTER CHRONIC SOCIAL DEFEAT STRESS REVERSES DEPRESSION-RELATED BEHAVIORS AND PRUNES STUBBY SPINES. TAKEN TOGETHER, OUR DATA IDENTIFY EPIGENETIC REGULATION OF RAC1 IN THE NAC AS A DISEASE MECHANISM IN DEPRESSION AND REVEAL A FUNCTIONAL ROLE FOR RAC1 IN RODENTS IN REGULATING STRESS-RELATED BEHAVIORS. 2013 14 4498 38 MORPHINE REGULATES ARGONAUTE 2 AND TH EXPRESSION AND ACTIVITY BUT NOT MIR-133B IN MIDBRAIN DOPAMINERGIC NEURONS. EPIGENETIC CHANGES SUCH AS MICRORNAS (MIRS)/AGO2-INDUCED GENE SILENCING REPRESENT COMPLEX MOLECULAR SIGNATURE THAT REGULATE CELLULAR PLASTICITY. RECENT STUDIES SHOWED INVOLVEMENT OF MIRS AND AGO2 IN DRUG ADDICTION. IN THIS STUDY, WE SHOW THAT CHANGES IN GENE EXPRESSION INDUCED BY MORPHINE AND MORPHINE WITHDRAWAL OCCUR WITH CONCOMITANT EPIGENETIC MODIFICATIONS IN THE MESOLIMBIC DOPAMINERGIC (DA) PATHWAY [VENTRAL TEGMENTAL AREA (VTA)/NUCLEUS ACCUMBENS (NAC) SHELL], WHICH IS CRITICALLY INVOLVED IN DRUG-INDUCED DEPENDENCE. WE FOUND THAT ACUTE OR CHRONIC MORPHINE ADMINISTRATION AS WELL AS MORPHINE WITHDRAWAL DID NOT MODIFY MIR-133B MESSENGER RNA (MRNA) EXPRESSION IN THE VTA, WHEREAS AGO2 PROTEIN LEVELS WERE DECREASED AND INCREASED IN MORPHINE-DEPENDENT RATS AND AFTER MORPHINE WITHDRAWAL, RESPECTIVELY. THESE CHANGES WERE PARALLELED WITH ENHANCED AND DECREASED NAC TYROSINE HYDROXYLASE (TH) PROTEIN (AN EARLY DA MARKER) IN MORPHINE-DEPENDENT RATS AND AFTER WITHDRAWAL, RESPECTIVELY. WE ALSO OBSERVED CHANGES IN TH MRNA EXPRESSION IN THE VTA THAT COULD BE RELATED TO AGO2-INDUCED TRANSLATIONAL REPRESSION OF TH MRNA DURING MORPHINE WITHDRAWAL. HOWEVER, THE VTA NUMBER OF TH-POSITIVE NEURONS SUFFERED NO ALTERATIONS AFTER THE DIFFERENT TREATMENT. ACUTE MORPHINE ADMINISTRATION PRODUCED A MARKED INCREASE IN TH ACTIVITY AND DA TURNOVER IN THE NAC (SHELL). IN CONTRAST, PRECIPITATED MORPHINE WITHDRAWAL DECREASED TH ACTIVATION AND DID NOT CHANGE DA TURNOVER. THESE FINDINGS PROVIDE NEW INFORMATION INTO THE POSSIBLE CORRELATION BETWEEN AGO2/MIRS COMPLEX REGULATION AND DA NEURONS PLASTICITY DURING OPIATE ADDICTION. 2015 15 1430 31 DIFFERENTIAL EXPRESSION OF SOX11 AND BDNF MRNA ISOFORMS IN THE INJURED AND REGENERATING NERVOUS SYSTEMS. IN BOTH THE CENTRAL NERVOUS SYSTEM (CNS) AND THE PERIPHERAL NERVOUS SYSTEM (PNS), AXONAL INJURY INDUCES CHANGES IN NEURONAL GENE EXPRESSION. IN THE PNS, A RELATIVELY WELL-CHARACTERIZED ALTERATION IN TRANSCRIPTIONAL ACTIVATION IS KNOWN TO PROMOTE AXONAL REGENERATION. THIS TRANSCRIPTIONAL CASCADE INCLUDES THE NEUROTROPHIN BDNF AND THE TRANSCRIPTION FACTOR SOX11. ALTHOUGH BOTH MOLECULES ACT TO FACILITATE SUCCESSFUL AXON REGENERATION IN THE PNS, THIS PROCESS DOES NOT OCCUR IN THE CNS. THE PRESENT STUDY EXAMINES THE DIFFERENTIAL EXPRESSION OF SOX11 AND BDNF MRNA ISOFORMS IN THE PNS AND CNS USING THREE EXPERIMENTAL PARADIGMS AT DIFFERENT TIME POINTS: (I) THE ACUTELY INJURED CNS (RETINA AFTER OPTIC NERVE CRUSH) AND PNS (DORSAL ROOT GANGLION AFTER SCIATIC NERVE CRUSH), (II) A CNS REGENERATION MODEL (RETINA AFTER OPTIC NERVE CRUSH AND INDUCED REGENERATION); AND (III) THE RETINA DURING A CHRONIC FORM OF CENTRAL NEURODEGENERATION (THE DBA/2J GLAUCOMA MODEL). WE FIND AN INITIAL INCREASE OF SOX11 IN BOTH PNS AND CNS AFTER INJURY; HOWEVER, THE EXPRESSION OF BDNF ISOFORMS IS HIGHER IN THE PNS RELATIVE TO THE CNS. SUSTAINED UPREGULATION OF SOX11 IS SEEN IN THE INJURED RETINA FOLLOWING REGENERATION TREATMENT, WHILE THE EXPRESSION OF TWO BDNF MRNA ISOFORMS IS SUPPRESSED. FURTHERMORE, TWO ISOFORMS OF SOX11 WITH DIFFERENT 3'UTR LENGTHS ARE PRESENT IN THE RETINA, AND THE LONG ISOFORM IS SPECIFICALLY UPREGULATED IN LATER STAGES OF GLAUCOMA. THESE RESULTS PROVIDE INSIGHT INTO THE MOLECULAR CASCADES ACTIVE DURING AXONAL INJURY AND REGENERATION IN MAMMALIAN NEURONS. 2017 16 532 19 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 17 5851 31 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 18 2883 22 G9A INHIBITS CREB-TRIGGERED EXPRESSION OF MU OPIOID RECEPTOR IN PRIMARY SENSORY NEURONS FOLLOWING PERIPHERAL NERVE INJURY. NEUROPATHIC PAIN, A DISTRESSING AND DEBILITATING DISORDER, IS STILL POORLY MANAGED IN CLINIC. OPIOIDS, LIKE MORPHINE, REMAIN THE MAINSTAY OF PRESCRIBED MEDICATIONS IN THE TREATMENT OF THIS DISORDER, BUT THEIR ANALGESIC EFFECTS ARE HIGHLY UNSATISFACTORY IN PART DUE TO NERVE INJURY-INDUCED REDUCTION OF OPIOID RECEPTORS IN THE FIRST-ORDER SENSORY NEURONS OF DORSAL ROOT GANGLIA. G9A IS A REPRESSOR OF GENE EXPRESSION. WE FOUND THAT NERVE INJURY-INDUCED INCREASES IN G9A AND ITS CATALYZED REPRESSIVE MARKER H3K9M2 ARE RESPONSIBLE FOR EPIGENETIC SILENCING OF OPRM1, OPRK1, AND OPRD1 GENES IN THE INJURED DORSAL ROOT GANGLIA. BLOCKING THESE INCREASES RESCUED DORSAL ROOT GANGLIA OPRM1, OPRK1, AND OPRD1 GENE EXPRESSION AND MORPHINE OR LOPERAMIDE ANALGESIA AND PREVENTED THE DEVELOPMENT OF MORPHINE OR LOPERAMIDE-INDUCED ANALGESIC TOLERANCE UNDER NEUROPATHIC PAIN CONDITIONS. CONVERSELY, MIMICKING THESE INCREASES REDUCED THE EXPRESSION OF THREE OPIOID RECEPTORS AND PROMOTED THE MU OPIOID RECEPTOR-GATED RELEASE OF PRIMARY AFFERENT NEUROTRANSMITTERS. MECHANISTICALLY, NERVE INJURY-INDUCED INCREASES IN THE BINDING ACTIVITY OF G9A AND H3K9ME2 TO THE OPRM1 GENE WERE ASSOCIATED WITH THE REDUCED BINDING OF CYCLIC AMP RESPONSE ELEMENT BINDING PROTEIN TO THE OPRM1 GENE. THESE FINDINGS SUGGEST THAT G9A PARTICIPATES IN THE NERVE INJURY-INDUCED REDUCTION OF THE OPRM1 GENE LIKELY THROUGH G9A-TRIGGERED BLOCKAGE IN THE ACCESS OF CYCLIC AMP RESPONSE ELEMENT BINDING PROTEIN TO THIS GENE. 2016 19 5627 18 SELECTIVE TARGETING OF THE STRESS CHAPEROME AS A THERAPEUTIC STRATEGY. NORMAL CELLULAR FUNCTION IS MAINTAINED BY COORDINATED PROTEOME MACHINERY THAT PERFORMS A VAST ARRAY OF ACTIVITIES. HELPING THE PROTEOME IN SUCH ROLES IS THE CHAPEROME, A NETWORK OF MOLECULAR CHAPERONES AND FOLDING ENZYMES. THE STRESSED CELL CONTAINS, AT ANY TIME, A COMPLEX MIXTURE OF CHAPEROME COMPLEXES; A MAJORITY PERFORMS 'HOUSEKEEPING FUNCTIONS' SIMILARLY TO NON-STRESSED, NORMAL CELLS, BUT A FINELY-TUNED FRACTION BUFFERS THE PROTEOME ALTERED BY CHRONIC STRESS. THE STRESS CHAPEROME IS EPIGENETICALLY DISTINCT FROM ITS NORMAL, HOUSEKEEPING COUNTERPART, PROVIDING A BASIS FOR ITS SELECTIVE TARGETING BY SMALL MOLECULES. WE DISCUSS HERE THE DEVELOPMENT OF CHAPEROME INHIBITORS, AND HOW AGENTS TARGETING CHAPEROME MEMBERS IN STRESSED CELLS ARE IN FACT BEING DIRECTED TOWARDS CHAPEROME COMPLEXES, AND THEIR EFFECT IS THEREFORE DETERMINED BY THEIR ABILITY TO SAMPLE AND ENGAGE SUCH COMPLEXES. A NEW APPROACH IS NEEDED TO TARGET AND IMPLEMENT CHAPEROME MODULATORS IN THE INVESTIGATION OF DISEASES, AND WE PROPOSE THAT THE CLASSICAL THINKING IN DRUG DISCOVERY NEEDS ADJUSTMENT WHEN DEVELOPING CHAPEROME-TARGETING DRUGS. 2014 20 764 30 CBP/P300 ACTIVATION PROMOTES AXON GROWTH, SPROUTING, AND SYNAPTIC PLASTICITY IN CHRONIC EXPERIMENTAL SPINAL CORD INJURY WITH SEVERE DISABILITY. THE INTERRUPTION OF SPINAL CIRCUITRY FOLLOWING SPINAL CORD INJURY (SCI) DISRUPTS NEURAL ACTIVITY AND IS FOLLOWED BY A FAILURE TO MOUNT AN EFFECTIVE REGENERATIVE RESPONSE RESULTING IN PERMANENT NEUROLOGICAL DISABILITY. FUNCTIONAL RECOVERY REQUIRES THE ENHANCEMENT OF AXONAL AND SYNAPTIC PLASTICITY OF SPARED AS WELL AS INJURED FIBRES, WHICH NEED TO SPROUT AND/OR REGENERATE TO FORM NEW CONNECTIONS. HERE, WE HAVE INVESTIGATED WHETHER THE EPIGENETIC STIMULATION OF THE REGENERATIVE GENE EXPRESSION PROGRAM CAN OVERCOME THE CURRENT INABILITY TO PROMOTE NEUROLOGICAL RECOVERY IN CHRONIC SCI WITH SEVERE DISABILITY. WE DELIVERED THE CBP/P300 ACTIVATOR CSP-TTK21 OR VEHICLE CSP WEEKLY BETWEEN WEEK 12 AND 22 FOLLOWING A TRANSECTION MODEL OF SCI IN MICE HOUSED IN AN ENRICHED ENVIRONMENT. DATA ANALYSIS SHOWED THAT CSP-TTK21 ENHANCED CLASSICAL REGENERATIVE SIGNALLING IN DORSAL ROOT GANGLIA SENSORY BUT NOT CORTICAL MOTOR NEURONS, STIMULATED MOTOR AND SENSORY AXON GROWTH, SPROUTING, AND SYNAPTIC PLASTICITY, BUT FAILED TO PROMOTE NEUROLOGICAL SENSORIMOTOR RECOVERY. THIS WORK PROVIDES DIRECT EVIDENCE THAT CLINICALLY SUITABLE PHARMACOLOGICAL CBP/P300 ACTIVATION CAN PROMOTE THE EXPRESSION OF REGENERATION-ASSOCIATED GENES AND AXONAL GROWTH IN A CHRONIC SCI WITH SEVERE NEUROLOGICAL DISABILITY. 2022