1 3721 149 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 2 1120 60 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 3 3191 48 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 4 1105 45 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 5 5865 45 SUPPRESSION OF HDAC2 IN SPINAL CORD ALLEVIATES MECHANICAL HYPERALGESIA AND RESTORES KCC2 EXPRESSION IN A RAT MODEL OF BONE CANCER PAIN. EPIGENETIC MODULATION PARTICIPATES IN THE MECHANISM OF MULTIPLE TYPES OF PATHOLOGICAL PAIN, SO TARGETING THE INVOLVED REGULATORS MAY BE A PROMISING STRATEGY FOR PAIN TREATMENT. OUR PREVIOUS RESEARCH IDENTIFIED THE ANALGESIC EFFECT OF THE HISTONE DEACETYLASE (HDAC) INHIBITOR TRICHOSTATIN A (TSA) ON MECHANICAL HYPERALGESIA IN A RAT MODEL OF BONE CANCER PAIN (BCP) VIA RESTORATION OF MU-OPIOID RECEPTOR (MOR) EXPRESSION. HOWEVER, THE SPECIFIC TYPES OF HDACS CONTRIBUTING TO BCP HAVE NOT BEEN EXPLORED. THE PRESENT STUDY INVESTIGATED THE EXPRESSION PATTERN OF SOME COMMON HDACS AND FOUND THAT HDAC2 WAS UP-REGULATED IN A TIME-DEPENDENT MANNER IN THE LUMBAR SPINAL CORD OF BCP RATS. TSA APPLICATION SUPPRESSED HDAC2 EXPRESSION IN CULTURED PC12 CELLS AND REVERSED THE AUGMENTED HDAC2 IN BCP RATS. AN RNA-INTERFERING STRATEGY CONFIRMED THE ESSENTIAL ROLE OF HDAC2 IN THE MODULATION OF MECHANICAL HYPERALGESIA FOLLOWING TUMOR CELL INOCULATION, AND WE FURTHER EXAMINED ITS POSSIBLE DOWNSTREAM TARGETS. NOTABLY, HDAC2 KNOCK-DOWN DID NOT RESTORE MOR EXPRESSION, BUT IT ROBUSTLY REVERSED THE DOWN-REGULATION OF POTASSIUM-CHLORIDE COTRANSPORTER 2 (KCC2). THE IMPAIRED KCC2 EXPRESSION IS A VITAL MECHANISM OF MANY TYPES OF PATHOLOGICAL PAIN. THEREFORE, OUR RESULTS DEMONSTRATED THAT HDAC2 IN SPINAL CORD CONTRIBUTED TO THE MECHANICAL HYPERALGESIA IN BCP RATS, AND THIS EFFECT MAY BE ASSOCIATED WITH KCC2 MODULATION. 2018 6 2249 55 EPIGENETIC MODULATION OF MGLU2 RECEPTORS BY HISTONE DEACETYLASE INHIBITORS IN THE TREATMENT OF INFLAMMATORY PAIN. KNOWING THAT EXPRESSION OF METABOTROPIC GLUTAMATE 2 (MGLU2) RECEPTORS IN THE DORSAL ROOT GANGLIA IS REGULATED BY ACETYLATION MECHANISMS, WE EXAMINED THE EFFECT OF TWO SELECTIVE AND CHEMICALLY UNRELATED HISTONE DEACETYLASE (HDAC) INHIBITORS, N-(2-AMINOPHENYL)-4-[N-(PYRIDINE-3-YLMETHOXY-CARBONYL)AMINOMETHYL]BENZAMIDE (MS-275) AND SUBEROYLANILIDE HYDROAMIC ACID (SAHA), IN A MOUSE MODEL OF PERSISTENT INFLAMMATORY PAIN. ALTHOUGH A SINGLE SUBCUTANEOUS INJECTION OF MS-275 (3 MG/KG) OR SAHA (5-50 MG/KG) WAS INEFFECTIVE, A 5-DAY TREATMENT WITH EITHER OF THE TWO HDAC INHIBITORS SUBSTANTIALLY REDUCED THE NOCICEPTIVE RESPONSE IN THE SECOND PHASE OF THE FORMALIN TEST, WHICH REFLECTS THE DEVELOPMENT OF CENTRAL SENSITIZATION IN THE DORSAL HORN OF THE SPINAL CORD. ANALGESIA WAS ABROGATED BY A SINGLE INJECTION OF THE MGLU2/3 RECEPTOR ANTAGONIST (ALPHAS)-ALPHA-AMINO-ALPHA-[(1S,2S)-2-CARBOXYCYCLOPROPYL]-9H-XANTINE-9-PROPANOIC ACID (LY341495; 1 MG/KG, I.P.), WHICH WAS INACTIVE PER SE. BOTH MS-275 AND SAHA UP-REGULATED THE EXPRESSION OF MGLU2 RECEPTORS IN THE DORSAL ROOT GANGLION (DRG) AND SPINAL CORD UNDER CONDITIONS IN WHICH THEY CAUSED ANALGESIA, WITHOUT CHANGING THE EXPRESSION OF MGLU1A, MGLU4, OR MGLU5 RECEPTORS. INDUCTION OF DRG MGLU2 RECEPTORS IN RESPONSE TO SAHA WAS ASSOCIATED WITH INCREASED ACETYLATION OF P65/RELA ON LYSINE 310, A PROCESS THAT ENHANCES THE TRANSCRIPTIONAL ACTIVITY OF P65/RELA AT NUCLEAR FACTOR-KAPPAB-REGULATED GENES. TRANSCRIPTION OF THE MGLU2 RECEPTOR GENE IS KNOWN TO BE ACTIVATED BY P65/RELA IN DRG NEURONS. WE CONCLUDE THAT HDAC INHIBITION PRODUCES ANALGESIA BY UP-REGULATING MGLU2 RECEPTOR EXPRESSION IN THE DRG, AN EFFECT THAT RESULTS FROM THE AMPLIFICATION OF NF-KAPPAB TRANSCRIPTIONAL ACTIVITY. THESE DATA PROVIDE THE FIRST EVIDENCE THAT HDAC INHIBITORS CAUSE ANALGESIA AND SUGGEST THAT HDACS ARE POTENTIAL TARGETS FOR THE EPIGENETIC TREATMENT OF PAIN. 2009 7 3323 41 HISTONE DEACETYLASE 1 (HDAC1): A KEY PLAYER OF T CELL-MEDIATED ARTHRITIS. RHEUMATOID ARTHRITIS (RA) REPRESENTS A CHRONIC T CELL-MEDIATED INFLAMMATORY AUTOIMMUNE DISEASE. STUDIES HAVE SHOWN THAT EPIGENETIC MECHANISMS CONTRIBUTE TO THE PATHOGENESIS OF RA. HISTONE DEACETYLASES (HDACS) REPRESENT ONE IMPORTANT GROUP OF EPIGENETIC REGULATORS. HOWEVER, THE ROLE OF INDIVIDUAL HDAC MEMBERS FOR THE PATHOGENESIS OF ARTHRITIS IS STILL UNKNOWN. IN THIS STUDY WE DEMONSTRATE THAT MICE WITH A T CELL-SPECIFIC DELETION OF HDAC1 (HDAC1-CKO) ARE RESISTANT TO THE DEVELOPMENT OF COLLAGEN-INDUCED ARTHRITIS (CIA), WHEREAS THE ANTIBODY RESPONSE TO COLLAGEN TYPE II WAS UNDISTURBED, INDICATING AN UNALTERED T CELL-MEDIATED B CELL ACTIVATION. THE INFLAMMATORY CYTOKINES IL-17 AND IL-6 WERE SIGNIFICANTLY DECREASED IN SERA OF HDAC1-CKO MICE. IL-6 TREATED HDAC1-DEFICIENT CD4(+) T CELLS SHOWED AN IMPAIRED UPREGULATION OF CCR6. SELECTIVE INHIBITION OF CLASS I HDACS WITH THE HDAC INHIBITOR MS-275 UNDER TH17-SKEWING CONDITIONS INHIBITED THE UPREGULATION OF CHEMOKINE RECEPTOR 6 (CCR6) IN MOUSE AND HUMAN CD4(+) T CELLS. ACCORDINGLY, ANALYSIS OF HUMAN RNA-SEQUENCING (RNA-SEQ) DATA AND HISTOLOGICAL ANALYSIS OF SYNOVIAL TISSUE SAMPLES FROM HUMAN RA PATIENTS REVEALED THE EXISTENCE OF CD4(+)CCR6(+) CELLS WITH ENHANCED HDAC1 EXPRESSION. OUR DATA INDICATE A KEY ROLE FOR HDAC1 FOR THE PATHOGENESIS OF CIA AND SUGGEST THAT HDAC1 AND OTHER CLASS I HDACS MIGHT BE PROMISING TARGETS OF SELECTIVE HDAC INHIBITORS (HDACI) FOR THE TREATMENT OF RA. 2020 8 1036 33 CLASS I HISTONE DEACETYLASES REGULATE P53/NF-KAPPAB CROSSTALK IN CANCER CELLS. THE TRANSCRIPTION FACTORS NF-KAPPAB AND P53 AS WELL AS THEIR CROSSTALK DETERMINE THE FATE OF TUMOR CELLS UPON THERAPEUTIC INTERVENTIONS. REPLICATIVE STRESS AND CYTOKINES PROMOTE SIGNALING CASCADES THAT LEAD TO THE CO-REGULATION OF P53 AND NF-KAPPAB. CONSEQUENTLY, NUCLEAR P53/NF-KAPPAB SIGNALING COMPLEXES ACTIVATE NF-KAPPAB-DEPENDENT SURVIVAL GENES. THE 18 HISTONE DEACETYLASES (HDACS) ARE EPIGENETIC MODULATORS THAT FALL INTO FOUR CLASSES (I-IV). INHIBITORS OF HISTONE DEACETYLASES (HDACI) BECOME INCREASINGLY APPRECIATED AS ANTI-CANCER AGENTS. BASED ON THEIR EFFECTS ON P53 AND NF-KAPPAB, WE ADDRESSED WHETHER CLINICALLY RELEVANT HDACI AFFECT THE NF-KAPPAB/P53 CROSSTALK. THE CHEMOTHERAPEUTICS HYDROXYUREA, ETOPOSIDE, AND FLUDARABINE HALT CELL CYCLE PROGRESSION, INDUCE DNA DAMAGE, AND LEAD TO DNA FRAGMENTATION. THESE AGENTS CO-INDUCE P53 AND NF-KAPPAB-DEPENDENT GENE EXPRESSION IN CELL LINES FROM BREAST AND COLON CANCER AND IN PRIMARY CHRONIC LYMPHATIC LEUKEMIA (CLL) CELLS. USING SPECIFIC HDACI, WE FIND THAT THE CLASS I SUBGROUP OF HDACS, BUT NOT THE CLASS IIB DEACETYLASE HDAC6, ARE REQUIRED FOR THE HYDROXYUREA-INDUCED CROSSTALK BETWEEN P53 AND NF-KAPPAB. HDACI DECREASE THE BASAL AND STRESS-INDUCED EXPRESSION OF P53 AND BLOCK NF-KAPPAB-REGULATED GENE EXPRESSION. WE FURTHER SHOW THAT CLASS I HDACI INDUCE SENESCENCE IN PANCREATIC CANCER CELLS WITH MUTANT P53. 2017 9 6172 49 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 10 3204 52 HDAC3 REGULATES GINGIVAL FIBROBLAST INFLAMMATORY RESPONSES IN PERIODONTITIS. HISTONE DEACETYLASES (HDACS) ARE IMPORTANT REGULATORS OF GENE EXPRESSION THAT ARE ABERRANTLY REGULATED IN SEVERAL INFLAMMATORY AND INFECTIOUS DISEASES. HDAC INHIBITORS (HDACI) SUPPRESS INFLAMMATORY ACTIVATION OF VARIOUS CELL TYPES THROUGH EPIGENETIC AND NON-EPIGENETIC MECHANISMS, AND AMELIORATE PATHOLOGY IN A MOUSE MODEL OF PERIODONTITIS. ACTIVATION OF GINGIVAL FIBROBLASTS (GFS) SIGNIFICANTLY CONTRIBUTES TO THE DEVELOPMENT OF PERIODONTITIS AND THE ANAEROBIC BACTERIUM PORPHYROMONAS GINGIVALIS PLAYS A KEY ROLE IN DRIVING CHRONIC INFLAMMATION. HERE, WE ANALYZED THE ROLE OF HDACS IN INFLAMMATORY RESPONSES OF GFS. PAN-HDACI SUBEROYLANILIDE HYDROXAMIC ACID (SAHA) AND/OR ITF2357 (GIVINOSTAT) SIGNIFICANTLY REDUCED TNFALPHA- AND P. GINGIVALIS-INDUCIBLE EXPRESSION AND/OR PRODUCTION OF A CLUSTER OF INFLAMMATORY MEDIATORS IN HEALTHY DONOR GFS (IL1B, CCL2, CCL5, CXCL10, COX2, AND MMP3) WITHOUT AFFECTING CELL VIABILITY. SELECTIVE INHIBITION OF HDAC3/6, BUT NOT SPECIFIC HDAC1, HDAC6, OR HDAC8 INHIBITION, REPRODUCED THE SUPPRESSIVE EFFECTS OF PAN-HDACI ON THE INFLAMMATORY GENE EXPRESSION PROFILE INDUCED BY TNFALPHA AND P. GINGIVALIS, SUGGESTING A CRITICAL ROLE FOR HDAC3 IN GF INFLAMMATORY ACTIVATION. CONSISTENTLY, SILENCING OF HDAC3 EXPRESSION WITH SIRNA LARGELY RECAPITULATED THE EFFECTS OF HDAC3/6I ON MRNA LEVELS OF INFLAMMATORY MEDIATORS IN P. GINGIVALIS-INFECTED GFS. IN CONTRAST, P. GINGIVALIS INTERNALIZATION AND INTRACELLULAR SURVIVAL IN GFS REMAINED UNAFFECTED BY HDACI. ACTIVATION OF MITOGEN-ACTIVATED PROTEIN KINASES AND NFKAPPAB SIGNALING WAS UNAFFECTED BY GLOBAL OR HDAC3/6-SELECTIVE HDACI, AND NEW PROTEIN SYNTHESIS WAS NOT REQUIRED FOR GENE SUPPRESSION BY HDACI. FINALLY, PAN-HDACI AND HDAC3/6I SUPPRESSED P. GINGIVALIS-INDUCED EXPRESSION OF IL1B, CCL2, CCL5, CXCL10, MMP1, AND MMP3 IN GFS FROM PATIENTS WITH PERIODONTITIS. OUR RESULTS IDENTIFY HDAC3 AS AN IMPORTANT REGULATOR OF INFLAMMATORY GENE EXPRESSION IN GFS AND SUGGEST THAT THERAPEUTIC TARGETING OF HDAC ACTIVITY, IN PARTICULAR HDAC3, MAY BE CLINICALLY BENEFICIAL IN SUPPRESSING INFLAMMATION IN PERIODONTAL DISEASE. 2020 11 2751 46 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 12 3197 35 HDAC INHIBITORS: TARGETS FOR TUMOR THERAPY, IMMUNE MODULATION AND LUNG DISEASES. HISTONE DEACETYLASES (HDACS) ARE ENZYMES THAT PLAY A KEY ROLE IN THE EPIGENETIC REGULATION OF GENE EXPRESSION BY REMODELING CHROMATIN. INHIBITION OF HDACS IS A PROSPECTIVE THERAPEUTIC APPROACH FOR REVERSING EPIGENETIC ALTERATION IN SEVERAL DISEASES. IN PRECLINICAL RESEARCH, NUMEROUS TYPES OF HDAC INHIBITORS WERE DISCOVERED TO EXHIBIT POWERFUL AND SELECTIVE ANTICANCER PROPERTIES. HOWEVER, SUCH RESEARCH HAS REVEALED THAT THE EFFECTS OF HDAC INHIBITORS MAY BE FAR BROADER AND MORE INTRICATE THAN PREVIOUSLY THOUGHT. THIS REVIEW WILL PROVIDE INSIGHT INTO THE HDAC INHIBITORS AND THEIR MECHANISM OF ACTION WITH SPECIAL EMPHASIS ON THE SIGNIFICANCE OF HDAC INHIBITORS IN THE TREATMENT OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE AND LUNG CANCER. NANOCARRIER-MEDIATED HDAC INHIBITOR DELIVERY AND NEW APPROACHES FOR TARGETING HDACS ARE ALSO DISCUSSED. 2022 13 3202 38 HDAC2 REGULATES ATYPICAL ANTIPSYCHOTIC RESPONSES THROUGH THE MODULATION OF MGLU2 PROMOTER ACTIVITY. HISTONE DEACETYLASES (HDACS) COMPACT CHROMATIN STRUCTURE AND REPRESS GENE TRANSCRIPTION. IN SCHIZOPHRENIA, CLINICAL STUDIES DEMONSTRATE THAT HDAC INHIBITORS ARE EFFICACIOUS WHEN GIVEN IN COMBINATION WITH ATYPICAL ANTIPSYCHOTICS. HOWEVER, THE MOLECULAR MECHANISM THAT INTEGRATES A BETTER RESPONSE TO ANTIPSYCHOTICS WITH CHANGES IN CHROMATIN STRUCTURE REMAINS UNKNOWN. HERE WE FOUND THAT CHRONIC ATYPICAL ANTIPSYCHOTICS DOWNREGULATED THE TRANSCRIPTION OF METABOTROPIC GLUTAMATE 2 RECEPTOR (MGLU2, ALSO KNOWN AS GRM2), AN EFFECT THAT WAS ASSOCIATED WITH DECREASED HISTONE ACETYLATION AT ITS PROMOTER IN MOUSE AND HUMAN FRONTAL CORTEX. THIS EPIGENETIC CHANGE OCCURRED IN CONCERT WITH A SEROTONIN 5-HT(2A) RECEPTOR-DEPENDENT UPREGULATION AND INCREASED BINDING OF HDAC2 TO THE MGLU2 PROMOTER. VIRALLY MEDIATED OVEREXPRESSION OF HDAC2 IN FRONTAL CORTEX DECREASED MGLU2 TRANSCRIPTION AND ITS ELECTROPHYSIOLOGICAL PROPERTIES, THEREBY INCREASING PSYCHOSIS-LIKE BEHAVIOR. CONVERSELY, HDAC INHIBITORS PREVENTED THE REPRESSIVE HISTONE MODIFICATIONS INDUCED AT THE MGLU2 PROMOTER BY ATYPICAL ANTIPSYCHOTICS, AND AUGMENTED THEIR THERAPEUTIC-LIKE EFFECTS. THESE OBSERVATIONS SUPPORT THE VIEW OF HDAC2 AS A PROMISING NEW TARGET FOR SCHIZOPHRENIA TREATMENT. 2012 14 2353 47 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 15 6138 35 THE ETIOLOGICAL CHANGES OF ACETYLATION IN PERIPHERAL NERVE INJURY-INDUCED NEUROPATHIC HYPERSENSITIVITY. NEUROPATHIC PAIN IS A COMMON CHRONIC PAIN CONDITION WITH MECHANISMS FAR CLEARLY BEEN ELUCIDATED. MOUNTING PRECLINICAL AND CLINICAL STUDIES HAVE SHOWN NEUROPATHIC PAIN IS HIGHLY ASSOCIATED WITH HISTONE ACETYLATION MODIFICATION, WHICH FOLLOWS EXPRESSION REGULATION OF VARIOUS PAIN-RELATED MOLECULES SUCH AS MGLUR1/5, GLUTAMATE ASPARTATE TRANSPORTER, GLUTAMATE TRANSPORTER-1, GAD65, NA(V)1.8, KV4.3, MU-OPIOID RECEPTOR, BRAIN-DERIVED NEUROTROPHIC FACTOR, AND CERTAIN CHEMOKINES. AS TWO TYPES OF PIVOTAL ENZYMES INVOLVED IN HISTONE ACETYLATION, HISTONE DEACETYLASES INDUCE HISTONE DEACETYLATION TO SILENCE GENE EXPRESSION; IN CONTRAST, HISTONE ACETYL TRANSFERASES FACILITATE HISTONE ACETYLATION TO POTENTIATE GENE TRANSCRIPTION. ACCORDINGLY, UPREGULATION OR BLOCKADE OF ACETYLATION MAY BE A PROMISING INTERVENTION DIRECTION FOR NEUROPATHIC PAIN TREATMENT. IN FACT, NUMEROUS ANIMAL STUDIES HAVE SUGGESTED VARIOUS HISTONE DEACETYLASE INHIBITORS, SIRT (CLASS III HISTONE DEACETYLASES) ACTIVATORS, AND HISTONE ACETYL TRANSFERASES INHIBITORS ARE EFFECTIVE IN NEUROPATHIC PAIN TREATMENT VIA TARGETING SPECIFIC EPIGENETIC SITES. IN THIS REVIEW, WE SUMMARIZE THE CHARACTERISTICS OF THE MOLECULES AND MECHANISMS OF NEUROPATHY-RELATED ACETYLATION, AS WELL AS THE ACETYLATION UPREGULATION AND BLOCKADE FOR NEUROPATHIC PAIN THERAPY. FINALLY, WE WILL DISCUSS THE CURRENT DRUG ADVANCES FOCUSING ON NEUROPATHY-RELATED ACETYLATION ALONG WITH THE UNDERLYING TREATMENT MECHANISMS. 2018 16 5947 33 TARGETING THE EPIGENOME: SCREENING BIOACTIVE COMPOUNDS THAT REGULATE HISTONE DEACETYLASE ACTIVITY. SCOPE: NUTRIGENOMICS IS A RAPIDLY EXPANDING FIELD THAT ELUCIDATES THE LINK BETWEEN DIET-GENOME INTERACTIONS. RECENT EVIDENCE DEMONSTRATES THAT REGULATION OF THE EPIGENOME, AND IN PARTICULAR INHIBITION OF HISTONE DEACETYLASES (HDACS), IMPACT PATHOGENETIC MECHANISMS INVOLVED IN CHRONIC DISEASE. FEW STUDIES, TO DATE, HAVE SCREENED LIBRARIES OF BIOACTIVE COMPOUNDS THAT ACT AS EPIGENETIC MODIFIERS. THIS STUDY SCREENED A LIBRARY OF 131 NATURAL COMPOUNDS TO DETERMINE BIOACTIVE COMPOUNDS THAT INHIBIT ZN-DEPENDENT HDAC ACTIVITY. METHODS AND RESULTS: USING CLASS-SPECIFIC HDAC SUBSTRATES, WE SCREENED 131 NATURAL COMPOUNDS FOR HDAC ACTIVITY IN BOVINE CARDIAC TISSUE. FROM THIS SCREEN, WE IDENTIFIED 18 BIOACTIVE COMPOUND HDAC INHIBITORS. USING OUR CLASS-SPECIFIC HDAC SUBSTRATES, WE NEXT SCREENED THESE 18 BIOACTIVE COMPOUNDS AGAINST RECOMBINANT HDAC PROTEINS. CONSISTENT WITH INHIBITION OF HDAC ACTIVITY, THESE COMPOUNDS WERE CAPABLE OF INHIBITING ACTIVITY OF INDIVIDUAL HDAC ISOFORMS. LASTLY, WE REPORT THAT TREATMENT OF H9C2 CARDIAC MYOBLASTS WITH BIOACTIVE HDAC INHIBITORS WAS SUFFICIENT TO INCREASE LYSINE ACETYLATION AS ASSESSED VIA IMMUNOBLOT. CONCLUSION: THIS STUDY PROVIDED THE FIRST STEP IN IDENTIFYING MULTIPLE BIOACTIVE COMPOUND HDAC INHIBITORS. TAKEN TOGETHER, THIS REPORT SETS THE STAGE FOR FUTURE EXPLORATION OF THESE BIOACTIVE COMPOUNDS AS EPIGENETIC REGULATORS TO POTENTIALLY AMELIORATE CHRONIC DISEASE. 2017 17 2068 40 EPIGENETIC CONTROL OF MICROSOMAL PROSTAGLANDIN E SYNTHASE-1 BY HDAC-MEDIATED RECRUITMENT OF P300. NONSTEROIDAL ANTI-INFLAMMATORY DRUGS ARE THE MOST WIDELY USED MEDICINE TO TREAT PAIN AND INFLAMMATION, AND TO INHIBIT PLATELET FUNCTION. UNDERSTANDING THE EXPRESSION REGULATION OF ENZYMES OF THE PROSTANOID PATHWAY IS OF GREAT MEDICAL RELEVANCE. HISTONE ACETYLATION CRUCIALLY CONTROLS GENE EXPRESSION. WE SET OUT TO IDENTIFY THE IMPACT OF HISTONE DEACETYLASES (HDACS) ON THE GENERATION OF PROSTANOIDS AND EXAMINE THE CONSEQUENCES ON VASCULAR FUNCTION. HDAC INHIBITION (HDACI) WITH THE PAN-HDAC INHIBITOR, VORINOSTAT, ATTENUATED PROSTAGLANDIN (PG)E(2) GENERATION IN THE MURINE VASCULATURE AND IN HUMAN VASCULAR SMOOTH MUSCLE CELLS. IN LINE WITH THIS, THE EXPRESSION OF THE KEY ENZYME FOR PGE(2) SYNTHESIS, MICROSOMAL PGE SYNTHASE-1 (PTGES1), WAS REDUCED BY HDACI. ACCORDINGLY, THE RELAXATION TO ARACHIDONIC ACID WAS DECREASED AFTER EX VIVO INCUBATION OF MURINE VESSELS WITH HDACI. TO IDENTIFY THE UNDERLYING MECHANISM, CHROMATIN IMMUNOPRECIPITATION (CHIP) AND CHIP-SEQUENCING ANALYSIS WERE PERFORMED. THESE RESULTS SUGGEST THAT HDACS ARE INVOLVED IN THE RECRUITMENT OF THE TRANSCRIPTIONAL ACTIVATOR P300 TO THE PTGES1 GENE AND THAT HDACI PREVENTED THIS EFFECT. IN LINE WITH THE ACETYLTRANSFERASE ACTIVITY OF P300, H3K27 ACETYLATION WAS REDUCED AFTER HDACI AND RESULTED IN THE FORMATION OF HETEROCHROMATIN IN THE PTGES1 GENE. IN CONCLUSION, HDAC ACTIVITY MAINTAINS PTGES1 EXPRESSION BY RECRUITING P300 TO ITS GENE. 2017 18 5995 33 TGFBETA-INDUCED FIBROBLAST ACTIVATION REQUIRES PERSISTENT AND TARGETED HDAC-MEDIATED GENE REPRESSION. TISSUE FIBROSIS IS A CHRONIC DISEASE DRIVEN BY PERSISTENT FIBROBLAST ACTIVATION THAT HAS RECENTLY BEEN LINKED TO EPIGENETIC MODIFICATIONS. HERE, WE SCREENED A SMALL LIBRARY OF EPIGENETIC SMALL-MOLECULE MODULATORS TO IDENTIFY COMPOUNDS CAPABLE OF INHIBITING OR REVERSING TGFBETA-MEDIATED FIBROBLAST ACTIVATION. WE IDENTIFIED PRACINOSTAT, AN HDAC INHIBITOR, AS A POTENT ATTENUATOR OF LUNG FIBROBLAST ACTIVATION AND CONFIRMED ITS EFFICACY IN PATIENT-DERIVED FIBROBLASTS ISOLATED FROM FIBROTIC LUNG TISSUE. MECHANISTICALLY, WE FOUND THAT HDAC-DEPENDENT TRANSCRIPTIONAL REPRESSION WAS AN EARLY AND ESSENTIAL EVENT IN TGFBETA-MEDIATED FIBROBLAST ACTIVATION. TREATMENT OF LUNG FIBROBLASTS WITH PRACINOSTAT BROADLY ATTENUATED TGFBETA-MEDIATED EPIGENETIC REPRESSION AND PROMOTED FIBROBLAST QUIESCENCE. WE CONFIRMED A SPECIFIC ROLE FOR HDAC-DEPENDENT HISTONE DEACETYLATION IN THE PROMOTER REGION OF THE ANTI-FIBROTIC GENE PPARGC1A (PGC1ALPHA) IN RESPONSE TO TGFBETA STIMULATION. FINALLY, WE IDENTIFIED HDAC7 AS A KEY FACTOR WHOSE SIRNA-MEDIATED KNOCKDOWN ATTENUATES FIBROBLAST ACTIVATION WITHOUT ALTERING GLOBAL HISTONE ACETYLATION. TOGETHER, THESE RESULTS PROVIDE NOVEL MECHANISTIC INSIGHT INTO THE ESSENTIAL ROLE HDACS PLAY IN TGFBETA-MEDIATED FIBROBLAST ACTIVATION VIA TARGETED GENE REPRESSION. 2019 19 3339 51 HISTONE DEACETYLASE ISOFORMS DIFFERENTIALLY MODULATE INFLAMMATORY AND AUTOANTIBODY RESPONSES IN A MOUSE MODEL OF MYASTHENIA GRAVIS. MYASTHENIA GRAVIS (MG) IS AN AUTOIMMUNE DISEASE CHARACTERIZED BY CHRONIC MUSCLE FATIGUE AND WEAKNESS CAUSED BY AUTOANTIBODIES AND COMPLEMENT-MEDIATED DAMAGE AT NEUROMUSCULAR JUNCTIONS. HISTONE DEACETYLASES (HDACS) ARE CRUCIAL EPIGENETIC REGULATORS OF PROINFLAMMATORY GENE EXPRESSION; HOWEVER, IT IS UNCLEAR WHETHER HDACS MODULATE CHRONIC INFLAMMATION OR AUTOANTIBODY PRODUCTION ASSOCIATED WITH MG PATHOGENESIS. WE EXAMINED EXPRESSION PROFILES AND SERUM LEVELS OF KEY INFLAMMATORY CYTOKINES (IL-6 AND IL-21) AND ACETYLCHOLINE RECEPTOR (ACHR)-SPECIFIC AUTOANTIBODIES FOLLOWING PHARMACOLOGICAL INHIBITION OF KEY HDAC ISOFORMS IN A MOUSE MODEL OF MG. WE FOUND THAT HDAC INHIBITION SIGNIFICANTLY REDUCED THE PRODUCTION OF IL-6, BUT NOT IL-21, IN ACHR-STIMULATED PBMCS AND SPLENOCYTES (N = 5 PER GROUP). TRICHOSTATIN (PAN-HDAC INHIBITOR) TREATMENT OF MG-PBMCS (N = 2) ALSO EXHIBITED REDUCED PRODUCTION OF INDUCED IL-6. ALTHOUGH HDAC1 INHIBITION LOWERED IL-6 LEVELS THE MOST, HDAC2 INHIBITION DEPLETED INTRACELLULAR IL-6 AND MARKEDLY REDUCED SERUM ANTI-ACHR IGG2B IN EAMG MICE. THE TRANSCRIPTOMIC PROFILING AND PATHWAY MAPPING ALSO REVEALED THAT AUTOIMMUNITY-LINKED, MAJOR CELL SIGNALING PATHWAYS WERE DIFFERENTIALLY ALTERED BY HDAC1/2 INHIBITION. HDAC INHIBITION-MEDIATED REDUCTION IN IL-6 AND AUTOANTIBODY LEVELS ALSO CORRELATED WITH MILDER DISEASE AND PRESERVATION OF MUSCLE ACHR IN THE TREATED MICE. OVERALL, OUR FINDINGS REVEALED ISOFORM-SPECIFIC FUNCTIONAL VARIANCE OF HDACS IN REDUCING INFLAMMATION AND IDENTIFIED HDAC-REGULATED MANY GENES UNDERLYING SPECIFIC INFLAMMATORY AND AUTOANTIBODY PATHWAYS IN EAMG. THUS, THE STUDY PROVIDES A RATIONALE FOR FURTHER RESEARCH TO EVALUATE THE HDACS OR THEIR GENE TARGETS AS A POTENTIAL ADJUNCT TREATMENT FOR MG. 2021 20 3196 32 HDAC INHIBITORS RESTORE C-FIBRE SENSITIVITY IN EXPERIMENTAL NEUROPATHIC PAIN MODEL. BACKGROUND AND PURPOSE: HYPOESTHESIA IS A CLINICAL FEATURE OF NEUROPATHIC PAIN. THE FEATURE IS PARTLY EXPLAINED BY THE EVIDENCE OF EPIGENETIC REPRESSION OF NAV 1.8 SODIUM CHANNEL IN THE DORSAL ROOT GANGLION (DRG). EXPERIMENTAL APPROACH: WE INVESTIGATED THE POSSIBILITY OF TRICHOSTATIN A (TSA), VALPROIC ACID (VPA) AND SUBEROYLANILIDE HYDROXAMIC ACID (SAHA) TO REVERSE THE UNIQUE C-FIBRE SENSITIVITY OBSERVED FOLLOWING PARTIAL LIGATION OF SCIATIC NERVE IN MICE. KEY RESULTS: NERVE INJURY-INDUCED DOWN-REGULATION OF DRG NAV 1.8 SODIUM CHANNEL AND C-FIBRE-RELATED HYPOESTHESIA WERE REVERSED BY TSA, VPA AND SAHA TREATMENTS, WHICH INHIBIT HISTONE DEACETYLASE (HDAC), AND INCREASE HISTONE ACETYLATION AT THE REGULATORY SEQUENCE OF NAV 1.8. CONCLUSIONS AND IMPLICATIONS: TAKEN TOGETHER, THESE STUDIES PROVIDE THE EVIDENCE THAT HYPOESTHESIA AND UNDERLYING DOWN-REGULATION OF NAV 1.8, NEGATIVE SYMPTOMS OBSERVED IN NERVE INJURY-INDUCED NEUROPATHIC PAIN MODELS ARE REGULATED BY AN EPIGENETIC CHROMATIN REMODELLING THROUGH HDAC-RELATED MACHINERIES. 2013