1 2364 174 EPIGENETIC REGULATION OF SPINAL CORD GENE EXPRESSION CONTROLS OPIOID-INDUCED HYPERALGESIA. BACKGROUND: THE LONG TERM USE OF OPIOIDS FOR THE TREATMENT OF PAIN LEADS TO A GROUP OF MALADAPTATIONS WHICH INCLUDES OPIOID-INDUCED HYPERALGESIA (OIH). OIH TYPICALLY RESOLVES WITHIN FEW DAYS AFTER CESSATION OF MORPHINE TREATMENT IN MICE BUT IS PROLONGED FOR WEEKS IF HISTONE DEACETYLASE (HDAC) ACTIVITY IS INHIBITED DURING OPIOID TREATMENT. THE PRESENT WORK SEEKS TO IDENTIFY GENE TARGETS SUPPORTING THE EPIGENETIC EFFECTS RESPONSIBLE FOR OIH PROLONGATION. RESULTS: MICE WERE TREATED WITH MORPHINE ACCORDING TO AN ASCENDING DOSE PROTOCOL. SOME MICE ALSO RECEIVED THE SELECTIVE HDAC INHIBITOR SUBEROYLANILIDE HYDROXAMIC ACID (SAHA) ADDITIONALLY. CHRONIC MORPHINE TREATMENT WITH SIMULTANEOUS HDAC INHIBITION ENHANCED OIH, AND SEVERAL SPINAL CORD GENES WERE UP-REGULATED. THE EXPRESSION OF BDNF (BRAIN-DERIVED NEUROTROPHIC FACTOR) AND PDYN (PRODYNORPHIN) WERE MOST CLOSELY RELATED TO THE OBSERVED BEHAVIORAL CHANGES. CHIP (CHROMATIN IMMUOPRECIPATION) ASSAYS DEMONSTRATED THAT PROMOTER REGIONS OF PDYN AND BDNF WERE STRONGLY ASSOCIATED WITH ACEH3K9 (ACETYLATED HISTONE H3 LYSINE9) AFTER MORPHINE AND SAHA TREATMENT. FURTHERMORE, MORPHINE TREATMENT CAUSED AN INCREASE IN SPINAL BDNF AND DYNORPHIN LEVELS, AND THESE LEVELS WERE FURTHER INCREASED IN SAHA TREATED MICE. THE SELECTIVE TRKB (TROPOMYOSIN-RECEPTOR-KINASE) ANTAGONIST ANA-12 REDUCED OIH WHEN GIVEN ONE OR SEVEN DAYS AFTER CESSATION OF MORPHINE. TREATMENT WITH THE SELECTIVE KAPPA OPIOID RECEPTOR ANTAGONIST NOR-BNI ALSO REDUCED ESTABLISHED OIH. THE CO-ADMINISTRATION OF EITHER RECEPTOR ANTAGONIST AGENT DAILY WITH MORPHINE RESULTED IN ATTENUATION OF HYPERALGESIA PRESENT ONE DAY AFTER CESSATION OF TREATMENT. ADDITIONALLY, REPEATED MORPHINE EXPOSURE INDUCED A RISE IN BDNF EXPRESSION THAT WAS ASSOCIATED WITH AN INCREASED NUMBER OF BDNF+ CELLS IN THE SPINAL CORD DORSAL HORN, SHOWING STRONG CO-LOCALIZATION WITH ACEH3K9 IN NEURONAL CELLS. LASTLY, SPINAL APPLICATION OF LOW DOSE BDNF OR DYNORPHIN A AFTER RESOLUTION OF OIH PRODUCED MECHANICAL HYPERSENSITIVITY, WITH NO EFFECT IN CONTROLS. CONCLUSIONS: THE PRESENT STUDY IDENTIFIED TWO GENES WHOSE EXPRESSION IS REGULATED BY EPIGENETIC MECHANISMS DURING MORPHINE EXPOSURE. TREATMENTS AIMED AT PREVENTING THE ACETYLATION OF HISTONES OR BLOCKING BDNF AND DYNORPHIN SIGNALING MAY REDUCE OIH AND IMPROVE LONG-TERM PAIN USING OPIOIDS. 2014 2 2353 63 EPIGENETIC REGULATION OF OPIOID-INDUCED HYPERALGESIA, DEPENDENCE, AND TOLERANCE IN MICE. REPEATED ADMINISTRATION OF OPIOIDS SUCH AS MORPHINE INDUCES PERSISTENT BEHAVIORAL CHANGES INCLUDING OPIOID-INDUCED HYPERALGESIA (OIH), TOLERANCE, AND PHYSICAL DEPENDENCE. IN THE CURRENT WORK WE EXPLORED HOW THE BALANCE OF HISTONE ACETYLTRANSFERASE (HAT) VERSUS HISTONE DEACETYLASE (HDAC) MIGHT REGULATE THESE MORPHINE-INDUCED CHANGES. NOCICEPTIVE THRESHOLDS, ANALGESIA, AND PHYSICAL DEPENDENCE WERE ASSESSED DURING AND FOR A PERIOD OF SEVERAL WEEKS AFTER MORPHINE EXPOSURE. TO PROBE THE ROLES OF HISTONE ACETYLATION, THE HAT INHIBITOR CURCUMIN OR A SELECTIVE HDAC INHIBITOR SUBEROYLANILIDE HYDROXAMIC ACID (SAHA) WAS ADMINISTERED DAILY TO GROUPS OF ANIMALS. HISTONE ACETYLATION IN SPINAL CORD WAS ASSESSED BY WESTERN BLOT AND IMMUNOHISTOCHEMISTRY. CONCURRENT ADMINISTRATION OF CURCUMIN WITH MORPHINE FOR 4 DAYS SIGNIFICANTLY REDUCED DEVELOPMENT OF OPIOID-INDUCED MECHANICAL ALLODYNIA, THERMAL HYPERALGESIA, TOLERANCE, AND PHYSICAL DEPENDENCE. CONVERSELY, THE HDAC INHIBITOR SAHA ENHANCED THESE RESPONSES. INTERESTINGLY, SAHA TREATMENT AFTER THE TERMINATION OF OPIOID ADMINISTRATION SUSTAINED THESE BEHAVIORAL CHANGES FOR AT LEAST 4 WEEKS. HISTONE H3 ACETYLATION IN THE DORSAL HORN OF THE SPINAL CORD WAS INCREASED AFTER CHRONIC MORPHINE TREATMENT, BUT H4 ACETYLATION WAS UNCHANGED. MOREOVER, WE OBSERVED A DECREASE IN HDAC ACTIVITY IN THE SPINAL CORDS OF MORPHINE-TREATED MICE WHILE OVERALL HAT ACTIVITY WAS UNCHANGED, SUGGESTING A SHIFT TOWARD A STATE OF ENHANCED HISTONE ACETYLATION. PERSPECTIVE: THE CURRENT STUDY INDICATES THAT EPIGENETIC MECHANISMS PLAY A CRUCIAL ROLE IN OPIOID-INDUCED LONG-LASTING NEUROPLASTICITY. THESE RESULTS PROVIDE NEW SIGHT INTO UNDERSTANDING THE MECHANISMS OF OPIOID-INDUCED NEUROPLASTICITY AND SUGGEST NEW STRATEGIES TO LIMIT OPIOID ABUSE POTENTIAL AND INCREASE THE VALUE OF THESE DRUGS AS ANALGESICS. 2013 3 3372 38 HISTONE MODIFICATIONS OF THE CRHR1 GENE IN A RAT MODEL OF DEPRESSION FOLLOWING CHRONIC STRESS. MULTIPLE LINES OF EVIDENCE SUGGEST A LINK BETWEEN DEPRESSION AND CHANGES IN HYPOTHALAMIC-PITUITARY-ADRENAL (HPA)-AXIS HORMONE DYNAMICS, INCLUDING ALTERED REGULATION OF THE CORTICOTROPHIN-RELEASING HORMONE (CRH) AND ITS MAIN RECEPTOR, CORTICOTROPHIN-RELEASING HORMONE RECEPTOR 1 (CRHR1). HOWEVER, THE PRECISE MOLECULAR MECHANISMS UNDERLYING DEPRESSION REMAIN POORLY UNDERSTOOD. IN THIS STUDY, WE EMPLOYED A MODEL OF DEPRESSION IN RATS BY SUBJECTING ANIMALS TO 21 DAYS OF CHRONIC UNPREDICTABLE MILD STRESS (CUMS). REAL-TIME PCR AND WESTERN BLOTTING WERE USED TO STUDY THE MRNA AND PROTEIN EXPRESSION LEVELS OF CRHR1 IN THE HYPOTHALAMUS. IN ADDITION, CHROMATIN IMMUNOPRECIPITATION ASSAYS WERE USED TO DETECT HISTONE METHYLATION AT THE CRHR1 GENE PROMOTER; THE LEVELS OF HISTONE H3 TRIMETHYLATION AT LYSINES 4 (H3K4) AND 9 (H3K9) REFLECT ACTIVE TRANSCRIPTION AND TRANSCRIPTIONAL REPRESSION, RESPECTIVELY. RATS EXPOSED TO CUMS EXHIBITED SIGNIFICANT REDUCTION IN LOCOMOTION AND SUCROSE PREFERENCE. THESE BEHAVIORAL ALTERATIONS WERE ASSOCIATED WITH ELEVATED EXPRESSION LEVELS OF CRHR1 MRNA AND PROTEIN IN THE HYPOTHALAMUS OF RATS IN THE CUMS GROUP. WE ALSO FOUND THAT THE LEVELS OF H3K9 TRIMETHYLATION AT THE CRHR1 GENE PROMOTER IN THE CUMS GROUP WERE SIGNIFICANTLY LOWER THAN THOSE IN THE CONTROL GROUP, WHEREAS H3K4 TRIMETHYLATION LEVELS WERE THE SAME FOR BOTH GROUPS. TAKEN TOGETHER, OUR FINDINGS SUGGEST THAT THE INCREASE IN CRHR1 EXPRESSION IN THE HYPOTHALAMUS OF STRESSED RATS CORRELATES WITH A DECREASE IN THE REPRESSIVE CHROMATIN STATE CAUSED BY REDUCED H3K9 TRIMETHYLATION LEVELS. THESE DATA ARE THE FIRST IN VIVO EVIDENCE OF A ROLE FOR CHROMATIN MODIFICATIONS IN THE REGULATION OF CRHR1 GENE EXPRESSION IN THE HYPOTHALAMUS, AND MAY PROVIDE NOVEL INSIGHT INTO THERAPEUTIC APPROACHES TO TREAT DEPRESSION. 2014 4 3191 50 HDAC AND HAT INHIBITORS DIFFERENTLY AFFECT ANALGESIA MEDIATED BY GROUP II METABOTROPIC GLUTAMATE RECEPTORS. BACKGROUND: HISTONE DEACETYLASES (HDACS) AND HISTONE ACETYLTRANSFERASES (HATS) ARE KEY PLAYERS IN EPIGENETIC REGULATION OF GENE EXPRESSION. ANALGESIC ACTIVITY BY HDAC INHIBITORS HAS BEEN REPORTED IN DIFFERENT PAIN MODELS INCLUDING INFLAMMATORY AND NEUROPATHIC PAIN. THESE DRUGS INTERFERE WITH GENE EXPRESSION THROUGH DIFFERENT MECHANISMS INCLUDING CHROMATIN REMODELING AND/OR ACTIVATION OF TRANSCRIPTION FACTORS. AMONG OTHER TARGETS, HDAC INHIBITORS REGULATE METABOTROPIC GLUTAMATE RECEPTORS TYPE 2 (MGLU2) EXPRESSION IN CENTRAL AND PERIPHERAL CENTRAL NERVOUS SYSTEM. HOWEVER WHETHER INHIBITION OF HAT ACTIVITY ALSO REGULATES MGLU2 EXPRESSION HAS NOT BEEN REPORTED. FINDINGS: HERE WE REPORT THAT CURCUMIN (CUR), A NATURALLY OCCURRING COMPOUND ENDOWED WITH P300/CREB-BINDING PROTEIN HAT INHIBITORY ACTIVITY, IS ABLE TO INDUCE A DRASTIC DOWN-REGULATION OF THE MGLU2 RECEPTOR IN THE MOUSE SPINAL CORD AFTER SYSTEMIC ADMINISTRATION TOGETHER WITH A MARKED HYPOACETYLATION OF HISTONES H3 AND H4 IN DORSAL ROOT GANGLIA (DRG). FURTHERMORE, THE ANALGESIC ACTIVITY OF THE MGLU2/3 AGONIST, LY379268 IS LOST AFTER A 3-DAY TREATMENT WITH CUR. CONVERSELY THE ANALGESIC ACTIVITY OF LY379268 IS POTENTIATED IN MICE PRETREATED FOR 5 CONSECUTIVE DAYS WITH THE HDAC INHIBITOR, SUBEROYLANILIDE HYDROXAMIC ACID (SAHA), KNOWN TO INDUCE MGLU2-UPREGULATION. CONCLUSIONS: OUR RESULTS DEMONSTRATE THAT SYSTEMICALLY INJECTED CUR IS ABLE TO INHIBIT H3 AND H4 ACETYLATION IN THE DRG AND TO DOWN-REGULATE MGLU2 RECEPTORS IN THE SPINAL CORD. WE ALSO DEMONSTRATE THAT LONG TERM MODIFICATION OF THE MGLU2 EXPRESSION AFFECTS THE ANALGESIC PROPERTIES OF THE ORTHOSTERIC MGLU2/3 AGONIST, LY379268. THESE DATA OPEN UP THE POSSIBILITY THAT EPIGENETIC MODULATORS MIGHT BE GIVEN IN COMBINATION WITH "TRADITIONAL" DRUGS IN A CONTEXT OF A MULTI TARGET APPROACH FOR A BETTER ANALGESIC EFFICACY. 2014 5 2363 76 EPIGENETIC REGULATION OF SPINAL CORD GENE EXPRESSION CONTRIBUTES TO ENHANCED POSTOPERATIVE PAIN AND ANALGESIC TOLERANCE SUBSEQUENT TO CONTINUOUS OPIOID EXPOSURE. BACKGROUND: OPIOIDS HAVE BECOME THE MAINSTAY FOR TREATMENT OF MODERATE TO SEVERE PAIN AND ARE COMMONLY USED TO TREAT SURGICAL PAIN. WHILE OPIOID ADMINISTRATION HAS BEEN SHOWN TO CAUSE OPIOID-INDUCED HYPERALGESIA AND TOLERANCE, INTERACTIONS BETWEEN OPIOID ADMINISTRATION AND SURGERY WITH RESPECT TO THESE PROBLEMATIC ADAPTATIONS HAVE SCARCELY BEEN ADDRESSED. ACCUMULATING EVIDENCE SUGGESTS OPIOIDS AND NOCICEPTIVE SIGNALING MAY CONVERGE ON EPIGENETIC MECHANISMS IN SPINAL CORD TO ENHANCE OR PROLONG NEUROPLASTIC CHANGES. EPIGENETIC REGULATION OF BDNF (BRAIN-DERIVED NEUROTROPHIC FACTOR) AND PDYN (PRODYNORPHIN) GENES MAY BE INVOLVED. RESULTS: FOUR DAYS OF ASCENDING DOSES OF MORPHINE TREATMENT CAUSED OPIOID-INDUCED HYPERALGESIA AND REDUCED OPIOID ANALGESIC EFFICACY IN MICE. BOTH OPIOID-INDUCED HYPERALGESIA AND THE REDUCED OPIOID ANALGESIC EFFICACY WERE ENHANCED IN MICE THAT RECEIVED HINDPAW INCISIONS. THE EXPRESSION OF BDNF AND PDYN (QPCR) WAS INCREASED AFTER MORPHINE TREATMENT AND INCISION. CHROMATIN IMMUNOPRECIPITATION ASSAYS DEMONSTRATED THAT THE PDYN AND BDNF PROMOTERS WERE MORE STRONGLY ASSOCIATED WITH ACETYLATED H3K9 AFTER MORPHINE PLUS INCISION THAN IN THE MORPHINE OR INCISION ALONE GROUPS. SELECTIVE TROPOMYOSIN-RELATED KINASE B (ANA-12) AND KAPPA-OPIOID RECEPTOR (NOR-BINALTORPHIMINE) ANTAGONISTS WERE ADMINISTERED INTRATHECALLY, BOTH REDUCED HYPERALGESIA ONE OR THREE DAYS AFTER SURGERY. ADMINISTRATION OF ANA-12 OR NOR-BINALTORPHIMINE ATTENUATED THE DECREASED MORPHINE ANALGESIC EFFICACY ON DAY 1, BUT ONLY NOR-BINALTORPHIMINE WAS EFFECTIVE ON DAY 3 AFTER INCISION IN OPIOID-EXPOSED GROUP. COADMINISTRATION OF HISTONE ACETYLTRANSFERASE INHIBITOR ANACARDIC ACID DAILY WITH MORPHINE BLOCKED THE DEVELOPMENT OF OPIOID-INDUCED HYPERALGESIA AND ATTENUATED INCISION-ENHANCED HYPERALGESIA IN MORPHINE-TREATED MICE. ANACARDIC ACID HAD SIMILAR EFFECTS ON ANALGESIC TOLERANCE, SHOWING THE INVOLVEMENT OF HISTONE ACETYLATION IN THE INTERACTIONS DETECTED. CONCLUSIONS: SPINAL EPIGENETIC CHANGES INVOLVING BDNF AND PDYN MAY CONTRIBUTE TO THE ENHANCED POSTOPERATIVE NOCICEPTIVE SENSITIZATION AND ANALGESIC TOLERANCE OBSERVED AFTER CONTINUOUS OPIOID EXPOSURE. TREATMENTS BLOCKING THE EPIGENETICALLY MEDIATED UP-REGULATION OF THESE GENES OR ADMINISTRATION OF TRKB OR KAPPA-OPIOID RECEPTOR ANTAGONISTS MAY IMPROVE THE CLINICAL UTILITY OF OPIOIDS, PARTICULARLY AFTER SURGERY. 2016 6 2365 54 EPIGENETIC REGULATION OF SPINAL CXCR2 SIGNALING IN INCISIONAL HYPERSENSITIVITY IN MICE. BACKGROUND: THE REGULATION OF GENE EXPRESSION IN NOCICEPTIVE PATHWAYS CONTRIBUTES TO THE INDUCTION AND MAINTENANCE OF PAIN SENSITIZATION. HISTONE ACETYLATION IS A KEY EPIGENETIC MECHANISM CONTROLLING CHROMATIN STRUCTURE AND GENE EXPRESSION. CHEMOKINE CC MOTIF RECEPTOR 2 (CXCR2) IS A PROINFLAMMATORY RECEPTOR IMPLICATED IN NEUROPATHIC AND INFLAMMATORY PAIN AND IS KNOWN TO BE REGULATED BY HISTONE ACETYLATION IN SOME SETTINGS. THE AUTHORS SOUGHT TO INVESTIGATE THE ROLE OF HISTONE ACETYLATION ON SPINAL CXCR2 SIGNALING AFTER INCISION. METHODS: GROUPS OF 5-8 MICE UNDERWENT HIND PAW INCISION. SUBEROYLANILIDE HYDROXAMIC ACID AND ANACARDIC ACID WERE USED TO INHIBIT HISTONE DEACETYLASE AND HISTONE ACETYLTRANSFERASE, RESPECTIVELY. BEHAVIORAL MEASURES OF THERMAL AND MECHANICAL SENSITIZATION AS WELL AS HYPERALGESIC PRIMING WERE USED. BOTH MESSAGE RNA QUANTIFICATION AND CHROMATIN IMMUNOPRECIPITATION ANALYSIS WERE USED TO STUDY THE REGULATION OF CXCR2 AND LIGAND EXPRESSION. FINALLY, THE SELECTIVE CXCR2 ANTAGONIST SB225002 WAS ADMINISTERED INTRATHECALLY TO REVEAL THE FUNCTION OF SPINAL CXCR2 RECEPTORS AFTER HIND PAW INCISION. RESULTS: SUBEROYLANILIDE HYDROXAMIC ACID SIGNIFICANTLY EXACERBATED MECHANICAL SENSITIZATION AFTER INCISION. CONVERSELY, ANACARDIC ACID REDUCED INCISIONAL SENSITIZATION AND ALSO ATTENUATED INCISION-INDUCED HYPERALGESIC PRIMING. OVERALL, ACETYLATED HISTONE H3 AT LYSINE 9 WAS INCREASED IN SPINAL CORD TISSUES AFTER INCISION, AND ENHANCED ASSOCIATION OF ACETYLATED HISTONE H3 AT LYSINE 9 WITH THE PROMOTER REGIONS OF CXCR2 AND KERATINOCYTE-DERIVED CHEMOKINE (CXCL1) WAS OBSERVED AS WELL. BLOCKING CXCR2 REVERSED MECHANICAL HYPERSENSITIVITY AFTER HIND PAW INCISION. CONCLUSIONS: HISTONE MODIFICATION IS AN IMPORTANT EPIGENETIC MECHANISM REGULATING INCISION-INDUCED NOCICEPTIVE SENSITIZATION. THE SPINAL CXCR2 SIGNALING PATHWAY IS ONE EPIGENETICALLY REGULATED PATHWAY CONTROLLING EARLY AND LATENT SENSITIZATION AFTER INCISION. 2013 7 1105 46 COMBINED INHIBITION OF HISTONE DEACETYLASES AND BET FAMILY PROTEINS AS EPIGENETIC THERAPY FOR NERVE INJURY-INDUCED NEUROPATHIC PAIN. CURRENT TREATMENTS FOR NEUROPATHIC PAIN HAVE OFTEN MODERATE EFFICACY AND PRESENT UNWANTED EFFECTS SHOWING THE NEED TO DEVELOP EFFECTIVE THERAPIES. ACCUMULATING EVIDENCE SUGGESTS THAT HISTONE ACETYLATION PLAYS ESSENTIAL ROLES IN CHRONIC PAIN AND THE ANALGESIC ACTIVITY OF HISTONE DEACETYLASES (HDACS) INHIBITORS IS DOCUMENTED. BROMODOMAIN AND EXTRA-TERMINAL DOMAIN (BET) PROTEINS ARE EPIGENETIC READERS THAT INTERACT WITH ACETYLATED LYSINE RESIDUES ON HISTONES, BUT LITTLE IS KNOWN ABOUT THEIR IMPLICATION IN NEUROPATHIC PAIN. THUS, THE CURRENT STUDY WAS AIMED TO INVESTIGATE THE EFFECT OF THE COMBINATION OF HDAC AND BET INHIBITORS IN THE SPARED NERVE INJURY (SNI) MODEL IN MICE. INTRANASAL ADMINISTRATION OF I-BET762 (BET INHIBITOR) OR SAHA (HDAC INHIBITOR) ATTENUATED THERMAL AND MECHANICAL HYPERSENSITIVITY AND THIS ANTIALLODYNIC ACTIVITY WAS IMPROVED BY CO-ADMINISTRATION OF BOTH DRUGS. SPINAL CORD SECTIONS OF SNI MICE SHOWED AN INCREASED EXPRESSION OF HDAC1 AND BRD4 PROTEINS AND COMBINATION PRODUCED A STRONGER REDUCTION COMPARED TO EACH EPIGENETIC AGENT ALONE. SAHA AND I-BET762, ADMINISTERED ALONE OR IN COMBINATION, COUNTERACTED THE SNI-INDUCED MICROGLIA ACTIVATION BY INHIBITING THE EXPRESSION OF IBA1, CD11B, INDUCIBLE NITRIC OXIDE SYNTHASE (INOS), THE ACTIVATION OF NUCLEAR FACTOR-KAPPAB (NF-KAPPAB) AND SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION-1 (STAT1) WITH COMPARABLE EFFICACY. CONVERSELY, THE EPIGENETIC INHIBITORS SHOWED A MODEST EFFECT ON SPINAL PROINFLAMMATORY CYTOKINES CONTENT THAT WAS SIGNIFICANTLY POTENTIATED BY THEIR COMBINATION. PRESENT RESULTS INDICATE A KEY ROLE OF ACETYLATED HISTONES AND THEIR RECRUITMENT BY BET PROTEINS ON MICROGLIA-MEDIATED SPINAL NEUROINFLAMMATION. TARGETING NEUROPATHIC PAIN WITH THE COMBINATION OF HDAC AND BET INHIBITORS MAY REPRESENT A PROMISING NEW THERAPEUTIC OPTION. 2021 8 3721 51 INHIBITION OF CLASS II HISTONE DEACETYLASES IN THE SPINAL CORD ATTENUATES INFLAMMATORY HYPERALGESIA. BACKGROUND: SEVERAL CLASSES OF HISTONE DEACETYLASES (HDACS) ARE EXPRESSED IN THE SPINAL CORD THAT IS A CRITICAL STRUCTURE OF THE NOCICEPTIVE PATHWAY. HDAC-REGULATED HISTONE ACETYLATION IS AN IMPORTANT COMPONENT OF CHROMATIN REMODELING LEADING TO EPIGENETIC REGULATION OF GENE TRANSCRIPTION. TO UNDERSTAND THE ROLE OF HISTONE ACETYLATION IN EPIGENETIC REGULATION OF PATHOLOGICAL PAIN, WE HAVE STUDIED THE IMPACT OF DIFFERENT CLASSES OF HDACS IN THE SPINAL CORD ON INFLAMMATORY HYPERALGESIA INDUCED BY COMPLETE FREUND'S ADJUVANT (CFA). RESULTS: WE INTRATHECALLY APPLIED INHIBITORS SPECIFIC TO DIFFERENT CLASSES OF HDACS AND EVALUATED THEIR IMPACT ON INFLAMMATORY HYPERALGESIA. PRE-INJECTED INHIBITORS TARGETING CLASS I AS WELL AS II (SAHA, TSA, LAQ824) OR IIA (VPA, 4-PB) HDACS SIGNIFICANTLY DELAYED THE THERMAL HYPERALGESIA INDUCED BY UNILATERAL CFA INJECTION IN THE HINDPAW. EXISTING HYPERALGESIA INDUCED BY CFA WAS ALSO ATTENUATED BY THE HDAC INHIBITORS (HDACIS). IN CONTRAST, THESE INHIBITORS DID NOT INTERFERE WITH THE THERMAL RESPONSE EITHER IN NAIVE ANIMALS, OR ON THE CONTRALATERAL SIDE OF INFLAMED ANIMALS. INTERESTINGLY, MS-275 THAT SPECIFICALLY INHIBITS CLASS I HDACS FAILED TO ALTER THE HYPERALGESIA ALTHOUGH IT INCREASED HISTONE 3 ACETYLATION IN THE SPINAL CORD AS SAHA DID. USING IMMUNOBLOT ANALYSIS, WE FURTHER FOUND THAT THE LEVELS OF CLASS IIA HDAC MEMBERS (HDAC4, 5, 7, 9) IN THE SPINAL DORSAL HORN WERE UPREGULATED FOLLOWING CFA INJECTION WHILE THOSE OF CLASS I HDAC MEMBERS (HDAC1, 2, 3) REMAINED STABLE OR WERE SLIGHTLY REDUCED. CONCLUSIONS: OUR DATA SUGGEST THAT ACTIVITY OF CLASS II HDACS IN THE SPINAL CORD IS CRITICAL TO THE INDUCTION AND MAINTENANCE OF INFLAMMATORY HYPERALGESIA INDUCED BY CFA, WHILE ACTIVITY OF CLASS I HDACS MAY BE UNNECESSARY. COMPARISON OF THE EFFECTS OF HDACIS SPECIFIC TO CLASS II AND IIA AS WELL AS THE EXPRESSION PATTERN OF DIFFERENT HDACS IN THE SPINAL CORD IN RESPONSE TO CFA SUGGESTS THAT THE MEMBERS OF CLASS IIA HDACS MAY BE POTENTIAL TARGETS FOR ATTENUATING PERSISTENT INFLAMMATORY PAIN. 2010 9 2745 48 EXPRESS: HISTONE HYPERACETYLATION MODULATES SPINAL TYPE II METABOTROPIC GLUTAMATE RECEPTOR ALLEVIATING STRESS-INDUCED VISCERAL HYPERSENSITIVITY IN FEMALE RATS. STRESS IS OFTEN A TRIGGER TO EXACERBATE CHRONIC PAIN INCLUDING VISCERAL HYPERSENSITIVITY ASSOCIATED WITH IRRITABLE BOWEL SYNDROME, A FEMALE PREDOMINANT FUNCTIONAL BOWEL DISORDER. EPIGENETIC MECHANISMS THAT MEDIATE STRESS RESPONSES ARE A POTENTIAL TARGET TO INTERFERE WITH VISCERAL PAIN. THE PURPOSE OF THIS STUDY WAS TO EXAMINE THE EFFECT OF A HISTONE DEACETYLASE INHIBITOR, SUBEROYLANILIDE HYDROXAMIC ACID, ON VISCERAL HYPERSENSITIVITY INDUCED BY A SUBCHRONIC STRESSOR IN FEMALE RATS AND TO INVESTIGATE THE INVOLVEMENT OF SPINAL GLUTAMATE RECEPTORS. THREE DAILY SESSIONS OF FORCED SWIM INDUCED VISCERAL HYPERSENSITIVITY. INTRATHECAL SUBEROYLANILIDE HYDROXAMIC ACID PREVENTED OR REVERSED THE STRESS-INDUCED VISCERAL HYPERSENSITIVITY, INCREASED SPINAL HISTONE 3 ACETYLATION AND INCREASED MGLUR2 AND MGLUR3 EXPRESSION. CHROMATIN IMMUNOPRECIPITATION (CHIP) ANALYSIS REVEALED ENRICHMENT OF H3K9AC AND H3K18AC AT SEVERAL PROMOTER GRM2 AND GRM3 REGIONS. THE MGLUR2/3 ANTAGONIST LY341495 REVERSED THE INHIBITORY EFFECT OF SUBEROYLANILIDE HYDROXAMIC ACID ON THE STRESS-INDUCED VISCERAL HYPERSENSITIVITY. IN SURPRISING CONTRAST, STRESS AND/OR SUBEROYLANILIDE HYDROXAMIC ACID HAD NO EFFECT ON SPINAL NMDA RECEPTOR EXPRESSION OR FUNCTION. THESE DATA REVEAL HISTONE MODIFICATION MODULATES MGLUR2/3 EXPRESSION IN THE SPINAL CORD TO ATTENUATE STRESSINDUCED VISCERAL HYPERSENSITIVITY. HDAC INHIBITORS MAY PROVIDE A POTENTIAL APPROACH TO RELIEVE VISCERAL HYPERSENSITIVITY ASSOCIATED WITH IRRITABLE BOWEL SYNDROME. 2016 10 193 28 ACETYLATION-MEDIATED EPIGENETIC REGULATION OF GLUCOCORTICOID RECEPTOR ACTIVITY: CIRCADIAN RHYTHM-ASSOCIATED ALTERATIONS OF GLUCOCORTICOID ACTIONS IN TARGET TISSUES. GLUCOCORTICOIDS INFLUENCE ORGAN FUNCTIONS THROUGH THE GLUCOCORTICOID RECEPTOR, A PROTEIN ACETYLATED AND DEACETYLATED BY SEVERAL HISTONE ACETYLTRANSFERASES AND DEACETYLASES. WE REPORTED THAT THE CIRCADIAN RHYTHM-RELATED TRANSCRIPTION FACTOR "CLOCK", A KEY COMPONENT OF THE BIOLOGICAL CLOCK WITH INHERENT HISTONE ACETYLTRANSFERASE ACTIVITY, ACETYLATES GLUCOCORTICOID RECEPTOR LYSINES WITHIN ITS HINGE REGION--A "LYSINE CLUSTER" CONTAINING A KXKK MOTIF--AND REPRESSES ITS TRANSCRIPTIONAL ACTIVITY. THIS CLOCK-INDUCED REPRESSION OF THE GLUCOCORTICOID RECEPTOR ACTIVITY IS INVERSELY PHASED TO THE DIURNALLY CIRCULATING GLUCOCORTICOIDS AND MAY ACT AS A LOCAL COUNTER REGULATORY MECHANISM TO THE ACTIONS OF THESE HORMONES. IMPORTANTLY, UNCOUPLING OF THE CENTRAL CLOCK-REGULATED HYPOTHALAMIC-PITUITARY-ADRENAL AXIS AND PERIPHERAL CLOCK-MEDIATED ALTERATIONS OF GLUCOCORTICOID ACTION, SUCH AS CHRONIC STRESS AND FREQUENT TRANS-TIME ZONE TRAVEL OR NIGHT-SHIFT WORK, MAY CAUSE FUNCTIONAL HYPERCORTISOLISM AND CONTRIBUTE TO VARIOUS PATHOLOGIES. THUS, ACETYLATION-MEDIATED EPIGENETIC REGULATION OF THE GLUCOCORTICOID RECEPTOR MAY BE ESSENTIAL FOR THE MAINTENANCE OF PROPER TIME-INTEGRATED GLUCOCORTICOID ACTION, SIGNIFICANTLY INFLUENCING HUMAN WELL-BEING AND LONGEVITY. 2011 11 2791 26 FAT-FREE P300 IS GOOD FOR SCAR-FREE TISSUE REPAIR. FIBROSIS, THE DEADLY PATHOLOGICAL MANIFESTATION OF AN ABNORMAL TISSUE REMODELING IN ANY ORGAN DUE TO EXCESSIVE COLLAGEN DEPOSITION, IS ASSOCIATED WITH A WIDE VARIETY OF ORGAN FAILURE-RELATED HUMAN DISEASES. CHRONIC STRESS OR REPEATED INJURY IN A PARTICULAR ORGAN INDUCES ABNORMAL MOLECULAR SIGNALS THAT LEAD TO SUPER-ACTIVATION OF MATRIX PROTEIN PRODUCING FIBROBLASTS, EXCESSIVE MATRIX PROTEINS ACCUMULATION, LOSS OF PHYSIOLOGICAL TISSUE ARCHITECTURE OR ELASTICITY, AND ULTIMATELY LEADING TO ORGAN FAILURE. THERE IS NO EFFECTIVE THERAPY FOR FIBROSIS. FACTOR ACETYLTRANSFERASE P300 (FATP300), A MAJOR EPIGENETIC REGULATOR THAT ACETYLATES SPECIFIC LYSINES IN HISTONES AND TRANSCRIPTION FACTORS, IS ESSENTIAL FOR ELEVATED COLLAGEN SYNTHESIS AND THE LEVELS OF FATP300 ARE SIGNIFICANTLY ELEVATED IN DIFFERENT FIBROTIC TISSUES. PHARMACOLOGICAL INHIBITION OF FAT ACTIVITY OF P300 IS ASSOCIATED WITH DECREASED COLLAGEN SYNTHESIS BY FIBROBLASTS IN TISSUES AND AMELIORATION OF ORGAN FIBROSIS. THEREFORE, FAT-FREE P300 IS SUPERIOR FOR PHYSIOLOGICAL TISSUE REPAIR AND MUST BE EXPLOITED AS A VIABLE THERAPEUTIC TARGET AGAINST MULTI-ORGAN FIBROSIS. 2014 12 1120 36 COMPARISON OF DIFFERENT HISTONE DEACETYLASE INHIBITORS IN ATTENUATING INFLAMMATORY PAIN IN RATS. HISTONE DEACETYLASE INHIBITORS (HDACIS), WHICH INTERFERE WITH THE EPIGENETIC PROCESS OF HISTONE ACETYLATION, HAVE SHOWN ANALGESIC EFFECTS IN ANIMAL MODELS OF PERSISTENT PAIN. THE HDAC FAMILY COMPRISES 18 GENES; HOWEVER, THE DIFFERENT EFFECTS OF DISTINCT CLASSES OF HDACIS ON PAIN RELIEF REMAIN UNCLEAR. THE AIM OF THIS STUDY WAS TO DETERMINE THE EFFICACY OF THESE HDACIS ON ATTENUATING THERMAL HYPERALGESIA IN PERSISTENT INFLAMMATORY PAIN. PERSISTENT INFLAMMATORY PAIN WAS INDUCED BY INJECTING COMPLETE FREUND'S ADJUVANT (CFA) INTO THE LEFT HIND PAW OF RATS. THEN, HDACIS TARGETING CLASS I (ENTINOSTAT (MS-275)) AND CLASS IIA (SODIUM BUTYRATE, VALPROIC ACID (VPA), AND 4-PHENYLBUTYRIC ACID (4-PBA)), OR CLASS II (SUBEROYLANILIDE HYDOXAMIC ACID (SAHA), TRICHOSTATIN A (TSA), AND DACINOSTAT (LAQ824)) WERE ADMINISTERED INTRAPERITONEALLY ONCE DAILY FOR 3 OR 4 DAYS. WE FOUND THAT THE INJECTION OF SAHA ONCE A DAY FOR 3 DAYS SIGNIFICANTLY ATTENUATED CFA-INDUCED THERMAL HYPERALGESIA FROM DAY 4 AND LASTED 7 DAYS. IN COMPARISON WITH SAHA, SUPPRESSION OF HYPERALGESIA BY 4-PBA PEAKED ON DAY 2, WHEREAS THAT BY MS-275 OCCURRED ON DAYS 5 AND 6. FATIGUE WAS A SERIOUS SIDE EFFECT SEEN WITH MS-275. THESE FINDINGS WILL BE BENEFICIAL FOR OPTIMIZING THE SELECTION OF SPECIFIC HDACIS IN MEDICAL FIELDS SUCH AS PAIN MEDICINE AND NEUROPSYCHIATRY. 2019 13 4906 45 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 14 1320 44 DEMETHYLATION REGULATION OF BDNF GENE EXPRESSION IN DORSAL ROOT GANGLION NEURONS IS IMPLICATED IN OPIOID-INDUCED PAIN HYPERSENSITIVITY IN RATS. REPEATED ADMINISTRATION OF MORPHINE MAY RESULT IN OPIOID-INDUCED HYPERSENSITIVITY (OIH), WHICH INVOLVES ALTERED EXPRESSION OF NUMEROUS GENES, INCLUDING BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) IN DORSAL ROOT GANGLION (DRG) NEURONS. YET, IT REMAINS UNCLEAR HOW BDNF EXPRESSION IS INCREASED IN DRG NEURONS AFTER REPEATED MORPHINE TREATMENT. DNA METHYLATION IS AN IMPORTANT MECHANISM OF EPIGENETIC CONTROL OF GENE EXPRESSION. IN THE CURRENT STUDY, WE HYPOTHESIZED THAT THE DEMETHYLATION REGULATION OF CERTAIN BDNF GENE PROMOTERS IN DRG NEURONS MAY CONTRIBUTE TO THE DEVELOPMENT OF OIH. REAL-TIME RT-PCR WAS USED TO ASSESS CHANGES IN THE MRNA TRANSCRIPTION LEVELS OF MAJOR BDNF EXONS INCLUDING EXON I, II, IV, VI, AS WELL AS TOTAL BDNF MRNA IN DRGS FROM RATS AFTER REPEATED MORPHINE ADMINISTRATION. THE LEVELS OF EXON IV AND TOTAL BDNF MRNA WERE SIGNIFICANTLY UPREGULATED BY REPEATED MORPHINE ADMINISTRATION, AS COMPARED TO THAT IN SALINE CONTROL GROUP. FURTHER, ELISA ARRAY AND IMMUNOCYTOCHEMISTRY STUDY REVEALED A ROBUST UPREGULATION OF BDNF PROTEIN EXPRESSION IN DRG NEURONS AFTER REPEATED MORPHINE EXPOSURE. CORRESPONDINGLY, THE METHYLATION LEVELS OF BDNF EXON IV PROMOTER SHOWED A SIGNIFICANT DOWNREGULATION BY MORPHINE TREATMENT. IMPORTANTLY, INTRATHECAL ADMINISTRATION OF A BDNF ANTIBODY, BUT NOT CONTROL IGG, SIGNIFICANTLY INHIBITED MECHANICAL HYPERSENSITIVITY THAT DEVELOPED IN RATS AFTER REPEATED MORPHINE TREATMENT. CONVERSELY, INTRATHECAL ADMINISTRATION OF AN INHIBITOR OF DNA METHYLATION, 5-AZA-2'-DEOXYCYTIDINE (5-AZA-DC) MARKEDLY UPREGULATED THE BDNF PROTEIN EXPRESSION IN DRG NEURONS AND ENHANCED THE MECHANICAL ALLODYNIA AFTER REPEATED MORPHINE EXPOSURE. TOGETHER, OUR FINDINGS SUGGEST THAT DEMETHYLATION REGULATION OF BDNF GENE PROMOTER MAY BE IMPLICATED IN THE DEVELOPMENT OF OIH THROUGH EPIGENETIC CONTROL OF BDNF EXPRESSION IN DRG NEURONS. 2016 15 5851 49 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 16 2476 39 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 17 2117 34 EPIGENETIC HISTONE METHYLATION MODULATES FIBROTIC GENE EXPRESSION. TGF-BETA1-INDUCED EXPRESSION OF EXTRACELLULAR MATRIX (ECM) GENES PLAYS A MAJOR ROLE IN THE DEVELOPMENT OF CHRONIC RENAL DISEASES SUCH AS DIABETIC NEPHROPATHY. ALTHOUGH MANY KEY TRANSCRIPTION FACTORS ARE KNOWN, MECHANISMS INVOLVING THE NUCLEAR CHROMATIN THAT MODULATE ECM GENE EXPRESSION REMAIN UNCLEAR. HERE, WE EXAMINED THE ROLE OF EPIGENETIC CHROMATIN MARKS SUCH AS HISTONE H3 LYSINE METHYLATION (H3KME) IN TGF-BETA1-INDUCED GENE EXPRESSION IN RAT MESANGIAL CELLS UNDER NORMAL AND HIGH-GLUCOSE (HG) CONDITIONS. TGF-BETA1 INCREASED THE EXPRESSION OF THE ECM-ASSOCIATED GENES CONNECTIVE TISSUE GROWTH FACTOR, COLLAGEN-ALPHA1[IOTA], AND PLASMINOGEN ACTIVATOR INHIBITOR-1. INCREASED LEVELS OF CHROMATIN MARKS ASSOCIATED WITH ACTIVE GENES (H3K4ME1, H3K4ME2, AND H3K4ME3), AND DECREASED LEVELS OF REPRESSIVE MARKS (H3K9ME2 AND H3K9ME3) AT THESE GENE PROMOTERS ACCOMPANIED THESE CHANGES IN EXPRESSION. TGF-BETA1 ALSO INCREASED EXPRESSION OF THE H3K4 METHYLTRANSFERASE SET7/9 AND RECRUITMENT TO THESE PROMOTERS. SET7/9 GENE SILENCING WITH SIRNAS SIGNIFICANTLY ATTENUATED TGF-BETA1-INDUCED ECM GENE EXPRESSION. FURTHERMORE, A TGF-BETA1 ANTIBODY NOT ONLY BLOCKED HG-INDUCED ECM GENE EXPRESSION BUT ALSO REVERSED HG-INDUCED CHANGES IN PROMOTER H3KME LEVELS AND SET7/9 OCCUPANCY. TAKEN TOGETHER, THESE RESULTS SHOW THE FUNCTIONAL ROLE OF EPIGENETIC CHROMATIN HISTONE H3KME IN TGF-BETA1-MEDIATED ECM GENE EXPRESSION IN MESANGIAL CELLS UNDER NORMAL AND HG CONDITIONS. PHARMACOLOGIC AND OTHER THERAPIES THAT REVERSE THESE MODIFICATIONS COULD HAVE POTENTIAL RENOPROTECTIVE EFFECTS FOR DIABETIC NEPHROPATHY. 2010 18 2482 52 EPIGENETIC UPREGULATION OF METABOTROPIC GLUTAMATE RECEPTOR 2 IN THE SPINAL CORD ATTENUATES OESTROGEN-INDUCED VISCERAL HYPERSENSITIVITY. OBJECTIVE: EPIGENETIC MECHANISMS ARE POTENTIAL TARGETS TO RELIEVE SOMATIC PAIN. HOWEVER, LITTLE IS KNOWN WHETHER EPIGENETIC REGULATION INTERFERES WITH VISCERAL PAIN. PREVIOUS STUDIES SHOW THAT OESTROGEN FACILITATES VISCERAL PAIN. THIS STUDY AIMED TO DETERMINE WHETHER HISTONE HYPERACETYLATION IN THE SPINAL CORD COULD ATTENUATE OESTROGEN-FACILITATED VISCERAL PAIN. DESIGN: THE EFFECT OF THE HISTONE DEACETYLASE INHIBITOR SUBEROYLANILIDE HYDROXAMIC ACID (SAHA) ON THE MAGNITUDE OF THE VISCEROMOTOR RESPONSE (VMR) TO COLORECTAL DISTENTION WAS EXAMINED IN OVARIECTOMISED RATS WITH/WITHOUT OESTROGEN REPLACEMENT. AN ADDITIONAL INTERACTION WITH THE METABOTROPIC GLUTAMATE RECEPTOR 2/3 (MGLUR2/3) ANTAGONIST LY341495 WAS TESTED. THE LEVELS OF ACETYLATED HISTONE AND MGLUR2 MRNA AND PROTEIN WERE ANALYSED. THE BINDING OF ACETYLATED H3 AND OESTROGEN RECEPTOR ALPHA (ERALPHA) TO THE GRM2 PROMOTER WAS MEASURED BY CHROMATIN IMMUNOPRECIPITATION COUPLED WITH QPCR. RESULTS: IN OVARIECTOMISED RATS, 17BETA-ESTRADIOL (E2), BUT NOT SAFFLOWER OIL, INCREASED THE MAGNITUDE OF THE VMR TO COLORECTAL DISTENTION. SAHA ATTENUATED THE E2-FACILITATED VMR, BUT HAD NO EFFECT IN SAFFLOWER OIL-TREATED RATS. SUBSEQUENT SPINAL ADMINISTRATION OF LY341495 REVERSED THE ANTINOCICEPTIVE EFFECT OF SAHA IN E2 RATS. IN ADDITION, SAHA INCREASED MGLUR2 MRNA AND PROTEIN IN THE SPINAL DORSAL HORN FOLLOWING E2, BUT NOT VEHICLE, TREATMENT. IN CONTRAST, NEITHER E2 NOR SAHA ALONE ALTERED MGLUR2 MRNA. SAHA INCREASED BINDING OF H3K9AC AND ERALPHA TO THE SAME REGIONS OF THE GRM2 PROMOTER IN E2-SAHA-TREATED ANIMALS. CONCLUSIONS: HISTONE HYPERACETYLATION IN THE SPINAL CORD ATTENUATES THE PRONOCICEPTIVE EFFECTS OF OESTROGEN ON VISCERAL SENSITIVITY, SUGGESTING THAT EPIGENETIC REGULATION MAY BE A POTENTIAL APPROACH TO RELIEVE VISCERAL PAIN. 2015 19 3832 38 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 20 596 35 BET PROTEINS: AN APPROACH TO FUTURE THERAPIES IN TRANSPLANTATION. IN ORDER TO DEVELOP NEW EFFICIENT THERAPIES FOR ORGAN TRANSPLANTATION, IT IS ESSENTIAL TO ACQUIRE A COMPREHENSIVE KNOWLEDGE OF THE MOLECULAR MECHANISMS AND PROCESSES, SUCH AS IMMUNE ACTIVATION, CHRONIC INFLAMMATION, AND FIBROSIS, WHICH LEAD TO REJECTION AND LONG-TERM GRAFT LOSS. RECENT EFFORTS HAVE SHED SOME LIGHT ON THE EPIGENETIC REGULATION ASSOCIATED WITH THESE PROCESSES. IN THIS CONTEXT, THE BROMO AND EXTRATERMINAL (BET) FAMILY OF BROMODOMAIN PROTEINS (BRD2, BRD3, BRD4, AND BRDT) HAVE EMERGED AS MAJOR EPIGENETIC PLAYERS, CONNECTING CHROMATIN STRUCTURE WITH GENE EXPRESSION CHANGES. THESE PROTEINS RECOGNIZE ACETYLATED LYSINES IN HISTONES AND MASTER TRANSCRIPTION FACTORS TO RECRUIT REGULATORY COMPLEX AND, FINALLY, MODIFY THE TRANSCRIPTIONAL PROGRAM. RECENT STUDIES INDICATE THAT BET PROTEINS ARE ESSENTIAL IN THE NF-KB-MEDIATED INFLAMMATORY RESPONSE, DURING THE ACTIVATION AND DIFFERENTIATION OF TH17-IMMUNE CELLS, AND IN PROFIBROTIC PROCESSES. HERE, WE REVIEW THIS NEW BODY OF DATA AND HIGHLIGHT THE EFFICIENCY OF BET INHIBITORS IN SEVERAL MODELS OF DISEASES. THE PROMISING RESULTS OBTAINED FROM THESE PRECLINICAL MODELS INDICATE THAT IT MAY BE TIME TO TRANSLATE THESE OUTCOMES TO THE TRANSPLANTATION FIELD, WHERE EPIGENETICS WILL BE OF INCREASING VALUE IN THE COMING YEARS. 2017