1 4841 145 ONE WEEK, BUT NOT 12 HOURS, OF CAST IMMOBILIZATION ALTERS PROMOTOR DNA METHYLATION PATTERNS IN THE NNOS GENE IN MOUSE SKELETAL MUSCLE. KEY POINTS: DNA METHYLATION MAY PLAY AN IMPORTANT ROLE IN REGULATING GENE EXPRESSION IN SKELETAL MUSCLE TO ADAPT TO PHYSICAL ACTIVITY AND INACTIVITY. NEURONAL NITRIC OXIDE SYNTHASE (NNOS) IN SKELETAL MUSCLE IS A KEY REGULATOR OF SKELETAL MUSCLE MASS; HOWEVER, IT IS UNCLEAR WHETHER NNOS EXPRESSION IS REGULATED BY DNA METHYLATION. WE FOUND THAT 1 WEEK OF CAST IMMOBILIZATION INCREASED NNOS DNA METHYLATION LEVELS AND DOWNREGULATED NNOS GENE EXPRESSION IN ATROPHIC SLOW-TWITCH SOLEUS MUSCLE FROM THE MOUSE LEG. THESE CHANGES WERE NOT DETECTED IN NON-ATROPHIC FAST-TWITCH EXTENSOR DIGITORUM LONGUS MUSCLE. TWELVE HOURS OF CAST IMMOBILIZATION DECREASED NNOS GENE EXPRESSION, WHEREAS NNOS DNA METHYLATION LEVELS WERE UNCHANGED, SUGGESTING THAT DOWNREGULATION OF NNOS GENE EXPRESSION BY SHORT-TERM MUSCLE INACTIVITY IS INDEPENDENT OF THE DNA METHYLATION PATTERN. THESE FINDINGS CONTRIBUTE TO A BETTER UNDERSTANDING OF THE MAINTENANCE OF SKELETAL MUSCLE MASS AND PREVENTION OF MUSCLE ATROPHY BY EPIGENETIC MECHANISMS VIA THE NNOS/NO PATHWAY. ABSTRACT: DNA METHYLATION IS A MECHANISM THAT CONTROLS GENE EXPRESSION IN SKELETAL MUSCLE UNDER VARIOUS ENVIRONMENTAL STIMULI, SUCH AS PHYSICAL ACTIVITY AND INACTIVITY. NEURONAL NITRIC OXIDE SYNTHASE (NNOS) REGULATES MUSCLE ATROPHY IN SKELETAL MUSCLE. HOWEVER, THE MECHANISMS REGULATING NNOS EXPRESSION IN ATROPHIC MUSCLE REMAIN UNCLEAR. WE HYPOTHESIZED THAT NNOS EXPRESSION IN ATROPHIC MUSCLE IS REGULATED BY DNA METHYLATION OF THE NNOS PROMOTOR IN SOLEUS (SOL; SLOW-TWITCH FIBRE DOMINANT) AND EXTENSOR DIGITORUM LONGUS (EDL; FAST-TWITCH FIBRE DOMINANT) MUSCLES. ONE WEEK OF CAST IMMOBILIZATION INDUCED SIGNIFICANT MUSCLE ATROPHY IN SOL BUT NOT IN EDL. WE SHOWED THAT 1 WEEK OF CAST IMMOBILIZATION INCREASED NNOS DNA METHYLATION LEVELS IN SOL, ALTHOUGH ONLY A MINOR CHANGE WAS DETECTED IN EDL. CONSISTENT WITH THE INCREASED DNA METHYLATION LEVELS IN ATROPHIC SOL, THE GENE EXPRESSION LEVELS OF TOTAL NNOS AND NNOSMICRO (I.E. THE MAJOR SPLICING VARIANT OF NNOS IN SKELETAL MUSCLE) DECREASED. THE ABUNDANCE OF THE NNOS PROTEIN AND CELL MEMBRANE (ESPECIALLY TYPE IIA FIBRE) IMMUNOREACTIVITY ALSO DECREASED IN ATROPHIC SOL. THESE CHANGES WERE NOT OBSERVED IN EDL AFTER 1 WEEK OF CAST IMMOBILIZATION. FURTHERMORE, DESPITE THE LACK OF SIGNIFICANT ATROPHY, 12 H OF CAST IMMOBILIZATION DECREASED GENE EXPRESSION LEVELS OF TOTAL NNOS AND NNOSMICRO IN SOL. HOWEVER, NO ASSOCIATION WAS DETECTED BETWEEN NNOS DNA METHYLATION AND GENE EXPRESSION. THE EXPRESSION OF THE NNOSBETA GENE, ANOTHER SPLICING VARIANT OF NNOS, IN EDL WAS UNCHANGED BY CAST IMMOBILIZATION, WHEREAS ITS EXPRESSION WAS NOT DETECTED IN SOL. WE CONCLUDED THAT CHRONIC ADAPTATION OF NNOS GENE EXPRESSION IN CAST IMMOBILIZED MUSCLE MAY INVOLVE NNOS DNA METHYLATION. 2019 2 4544 34 MUSCLE HYPERTROPHY IN HYPOXIA WITH INFLAMMATION IS CONTROLLED BY BROMODOMAIN AND EXTRA-TERMINAL DOMAIN PROTEINS. SOME OF THE CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) PATIENTS ENGAGED IN EXERCISE-BASED MUSCLE REHABILITATION PROGRAMS ARE UNRESPONSIVE. TO UNRAVEL THE RESPECTIVE ROLE OF CHRONIC HYPOXIA AND PULMONARY INFLAMMATION ON SOLEUS MUSCLE HYPERTROPHIC CAPACITIES, WE CHALLENGED MALE WISTAR RATS TO REPEATED LIPOPOLYSACCHARIDE INSTILLATIONS, ASSOCIATED OR NOT WITH A CHRONIC HYPOXIA EXPOSURE. MUSCLE HYPERTROPHY WAS INITIATED BY BILATERAL ABLATION OF SOLEUS AGONISTS 1 WEEK BEFORE SACRIFICE. TO UNDERSTAND THE ROLE PLAYED BY THE HISTONE ACETYLATION, WE ALSO TREATED OUR ANIMALS WITH AN INHIBITOR OF BROMODOMAINS AND EXTRA TERMINAL PROTEINS (I-BET) DURING THE WEEK AFTER SURGERY. PULMONARY INFLAMMATION TOTALLY INHIBITED THIS HYPERTROPHY RESPONSE UNDER BOTH NORMOXIC AND HYPOXIC CONDITIONS (26% LOWER THAN CONTROL SURGERY, P < 0.05), CONSISTENT WITH THE S6K1 AND MYOGENIN MEASUREMENTS. CHANGES IN HISTONE ACETYLATION AND CLASS IIA HISTONE DEACETYLASES EXPRESSION, FOLLOWING PULMONARY INFLAMMATION, SUGGESTED A PUTATIVE ROLE FOR HISTONE ACETYLATION SIGNALING IN THE ALTERED HYPERTROPHY RESPONSE. THE I-BET DRUG RESTORED THE HYPERTROPHY RESPONSE SUGGESTING THAT THE NON-RESPONSE OF MUSCLE TO A HYPERTROPHIC STIMULUS COULD BE MODULATED BY EPIGENETIC MECHANISMS, INCLUDING HISTONE-ACETYLATION DEPENDANT PATHWAYS. DRUGS TARGETING SUCH EPIGENETIC MECHANISMS MAY OPEN THERAPEUTIC PERSPECTIVES FOR COPD PATIENTS WITH SYSTEMIC INFLAMMATION WHO ARE UNRESPONSIVE TO REHABILITATION. 2017 3 5334 37 QUADRICEPS MUSCLE WEAKNESS AND ATROPHY ARE ASSOCIATED WITH A DIFFERENTIAL EPIGENETIC PROFILE IN ADVANCED COPD. EPIGENETIC MECHANISMS REGULATE MUSCLE MASS AND FUNCTION IN MODELS OF MUSCLE DYSFUNCTION AND ATROPHY. WE ASSESSED WHETHER QUADRICEPS MUSCLE WEAKNESS AND ATROPHY ARE ASSOCIATED WITH A DIFFERENTIAL EXPRESSION PROFILE OF EPIGENETIC EVENTS IN PATIENTS WITH ADVANCED COPD (CHRONIC OBSTRUCTIVE PULMONARY DISEASE). IN VASTUS LATERALIS (VL) OF SEDENTARY SEVERE COPD PATIENTS (N=41), WHO WERE FURTHER SUBDIVIDED INTO THOSE WITH (N=25) AND WITHOUT (N=16) MUSCLE WEAKNESS AND HEALTHY CONTROLS (N=19), EXPRESSION OF MUSCLE-ENRICHED MIRNAS, HISTONE ACETYLTRANSFERASES (HATS) AND DEACETYLASES (HDACS), GROWTH AND ATROPHY SIGNALLING MARKERS, TOTAL PROTEIN AND HISTONE ACETYLATION, TRANSCRIPTION FACTORS, SMALL UBIQUITIN-RELATED MODIFIER (SUMO) LIGASES AND MUSCLE STRUCTURE WERE EXPLORED. ALL SUBJECTS WERE CLINICALLY EVALUATED. COMPARED WITH CONTROLS, IN VL OF ALL COPD TOGETHER AND IN MUSCLE-WEAKNESS PATIENTS, EXPRESSION OF MIR-1, MIR-206 AND MIR-27A, LEVELS OF LYSINE-ACETYLATED PROTEINS AND HISTONES AND ACETYLATED HISTONE 3 WERE INCREASED, WHEREAS EXPRESSION OF HDAC3, HDAC4, SIRTUIN-1 (SIRT-1), IGF-1 (INSULIN-LIKE GROWTH FACTOR-1) WERE DECREASED, AKT (V-AKT MURINE THYMOMA VIRAL ONCOGENE HOMOLOGUE 1) EXPRESSION DID NOT DIFFER, FOLLISTATIN EXPRESSION WAS GREATER, WHEREAS MYOSTATIN EXPRESSION WAS LOWER, SERUM REPONSE FACTOR (SRF) EXPRESSION WAS INCREASED AND FIBRE SIZE OF FAST-TWITCH FIBRES WAS SIGNIFICANTLY REDUCED. IN VL OF SEVERE COPD PATIENTS WITH MUSCLE WEAKNESS AND ATROPHY, EPIGENETIC EVENTS REGULATE MUSCLE DIFFERENTIATION RATHER THAN PROLIFERATION AND MUSCLE GROWTH AND ATROPHY SIGNALLING, PROBABLY AS FEEDBACK MECHANISMS TO PREVENT THOSE MUSCLES FROM UNDERGOING FURTHER ATROPHY. LYSINE-HYPERACETYLATION OF HISTONES MAY DRIVE ENHANCED PROTEIN CATABOLISM IN THOSE MUSCLES. THESE FINDINGS MAY HELP DESIGN NOVEL THERAPEUTIC STRATEGIES (ENHANCERS OF MIRNAS PROMOTING MYOGENESIS AND ACETYLATION INHIBITORS) TO SELECTIVELY TARGET MUSCLE WEAKNESS AND ATROPHY IN SEVERE COPD. 2015 4 2681 36 EVALUATION OF MUSCLE-SPECIFIC AND METABOLISM REGULATING MICRORNAS IN A CHRONIC SWIMMING RAT MODEL. MAKING BENEFIT FROM THE EPIGENETIC EFFECTS OF ENVIRONMENTAL FACTORS SUCH AS PHYSICAL ACTIVITY MAY RESULT IN A CONSIDERABLE IMPROVEMENT IN THE PREVENTION OF CHRONIC CIVILIZATION DISEASES. IN OUR CHRONIC SWIMMING RAT MODEL, THE EXPRESSION LEVELS OF SUCH MICRORNAS WERE CHARACTERIZED, THAT ARE INVOLVED IN SKELETAL MUSCLE DIFFERENTIATION, HYPERTROPHY AND FINE-TUNING OF METABOLISM, WHICH PROCESSES ARE INFLUENCED BY CHRONIC ENDURANCE TRAINING, CONTRIBUTING TO THE METABOLIC ADAPTATION OF SKELETAL MUSCLE DURING PHYSICAL ACTIVITY. AFTER CHRONIC SWIMMING, THE LEVEL OF MIR-128A INCREASED SIGNIFICANTLY IN EDL MUSCLES, WHICH MAY INFLUENCE METABOLIC ADAPTATION AND STRESS RESPONSE AS WELL. IN SOL, THE EXPRESSION LEVEL OF MIR-15B AND MIR-451 DECREASED SIGNIFICANTLY AFTER CHRONIC SWIMMING, WHICH CHANGES ARE OPPOSITE TO THEIR PREVIOUSLY DESCRIBED INCREMENT IN INSULIN RESISTANT SKELETAL MUSCLE. MIR-451 ALSO TARGETS PGC-1ALPHA MRNA, WHICHES EXPRESSION LEVEL SIGNIFICANTLY INCREASED IN SOL MUSCLES, RESULTING IN ENHANCED BIOGENESIS AND OXIDATIVE CAPACITY OF MITOCHONDRIA. IN SUMMARY, THE MICRORNA EXPRESSION CHANGES THAT WERE OBSERVED DURING OUR EXPERIMENTS SUGGEST THAT CHRONIC SWIM TRAINING CONTRIBUTES TO A BENEFICIAL METABOLIC PROFILE OF SKELETAL MUSCLE. 2022 5 3721 40 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 6 169 38 ABNORMALITIES OF AMPK ACTIVATION AND GLUCOSE UPTAKE IN CULTURED SKELETAL MUSCLE CELLS FROM INDIVIDUALS WITH CHRONIC FATIGUE SYNDROME. BACKGROUND: POST EXERTIONAL MUSCLE FATIGUE IS A KEY FEATURE IN CHRONIC FATIGUE SYNDROME (CFS). ABNORMALITIES OF SKELETAL MUSCLE FUNCTION HAVE BEEN IDENTIFIED IN SOME BUT NOT ALL PATIENTS WITH CFS. TO TRY TO LIMIT POTENTIAL CONFOUNDERS THAT MIGHT CONTRIBUTE TO THIS CLINICAL HETEROGENEITY, WE DEVELOPED A NOVEL IN VITRO SYSTEM THAT ALLOWS COMPARISON OF AMP KINASE (AMPK) ACTIVATION AND METABOLIC RESPONSES TO EXERCISE IN CULTURED SKELETAL MUSCLE CELLS FROM CFS PATIENTS AND CONTROL SUBJECTS. METHODS: SKELETAL MUSCLE CELL CULTURES WERE ESTABLISHED FROM 10 SUBJECTS WITH CFS AND 7 AGE-MATCHED CONTROLS, SUBJECTED TO ELECTRICAL PULSE STIMULATION (EPS) FOR UP TO 24H AND EXAMINED FOR CHANGES ASSOCIATED WITH EXERCISE. RESULTS: IN THE BASAL STATE, CFS CULTURES SHOWED INCREASED MYOGENIN EXPRESSION BUT DECREASED IL6 SECRETION DURING DIFFERENTIATION COMPARED WITH CONTROL CULTURES. CONTROL CULTURES SUBJECTED TO 16 H EPS SHOWED A SIGNIFICANT INCREASE IN BOTH AMPK PHOSPHORYLATION AND GLUCOSE UPTAKE COMPARED WITH UNSTIMULATED CELLS. IN CONTRAST, CFS CULTURES SHOWED NO INCREASE IN AMPK PHOSPHORYLATION OR GLUCOSE UPTAKE AFTER 16 H EPS. HOWEVER, GLUCOSE UPTAKE REMAINED RESPONSIVE TO INSULIN IN THE CFS CELLS POINTING TO AN EXERCISE-RELATED DEFECT. IL6 SECRETION IN RESPONSE TO EPS WAS SIGNIFICANTLY REDUCED IN CFS COMPARED WITH CONTROL CULTURES AT ALL TIME POINTS MEASURED. CONCLUSION: EPS IS AN EFFECTIVE MODEL FOR ELICITING MUSCLE CONTRACTION AND THE METABOLIC CHANGES ASSOCIATED WITH EXERCISE IN CULTURED SKELETAL MUSCLE CELLS. WE FOUND FOUR MAIN DIFFERENCES IN CULTURED SKELETAL MUSCLE CELLS FROM SUBJECTS WITH CFS; INCREASED MYOGENIN EXPRESSION IN THE BASAL STATE, IMPAIRED ACTIVATION OF AMPK, IMPAIRED STIMULATION OF GLUCOSE UPTAKE AND DIMINISHED RELEASE OF IL6. THE RETENTION OF THESE DIFFERENCES IN CULTURED MUSCLE CELLS FROM CFS SUBJECTS POINTS TO A GENETIC/EPIGENETIC MECHANISM, AND PROVIDES A SYSTEM TO IDENTIFY NOVEL THERAPEUTIC TARGETS. 2015 7 6388 37 THE ROLE OF SIRT1 IN THE BASOLATERAL AMYGDALA IN DEPRESSION-LIKE BEHAVIORS IN MICE. PREVIOUS INVESTIGATIONS HAVE IMPLICATED THE BASOLATERAL AMYGDALA (BLA) EPIGENETIC MECHANISMS IN THE PATHOPHYSIOLOGY OF DEPRESSION. SIRT1 IS A NAD+-DEPENDENT CLASS III HISTONE DEACETYLASE, WIDELY EXPRESSES IN BLA. HOWEVER, EPIGENETIC MECHANISMS IN THE BLA UNDER THE REGULATION OF SIRT1 IN THE DEPRESSION ARE LARGELY UNCHARACTERIZED. UNDER THE CHRONIC UNPREDICTABLE CHRONIC MILD STRESS (CUMS) MOUSE MODEL, WE USED ADENO-ASSOCIATED VIRAL VECTORS (AAV) THAT ENCODED SIRT1-SHRNA OR SIRT1 TO SPECIFICALLY KNOCKDOWN OR OVEREXPRESS SIRT1 IN BLA NEURONS, RESPECTIVELY. CUMS PROCEDURE INDUCED SIGNIFICANT DEPRESSION SYMPTOMS INCLUDING THE DECREASED SUCROSE PREFERENCE, THE LESS BODYWEIGHT GAINED, THE DECREASED IMMOBILE LATENCY AND THE INCREASED IMMOBILE TIME BOTH IN FORCED SWIM TEST (FST) AND TAIL SUSPENSION TEST (TST). KNOCKDOWN OF SIRT1 IN BLA GLUTAMATERGIC NEURONS REVERSED THESE DEPRESSION-LIKE BEHAVIORS AND RESTORED THE SYNAPTIC ABNORMALITIES. OVEREXPRESSION OF SIRT1 IN BLA GLUTAMATERGIC NEURONS INDUCED DEPRESSION-LIKE BEHAVIORS IN NON-STRESSED CONTROL MICE. THE RESULT OF PROTEIN EXPRESSIONS AND ULTRASTRUCTURAL CHANGES WERE CONSISTENT WITH THE BEHAVIORAL RESULTS. OUR STUDY SUGGESTED THAT DOWNREGULATION OF SIRT1 IN BLA HAS CERTAIN BENEFICIAL EFFECT ON CUMS-INDUCED DEPRESSION-LIKE BEHAVIORS SUCH AS ANOREXIA, ANHEDONIA, HOPELESSNESS AND DESPAIR. IN ADDITION, THE INCREASED EXPRESSION OF SIRT1 MAY BE THE IMMEDIATE CAUSE OF DEPRESSIVE-LIKE SYMPTOMS. THE ABNORMAL EXPRESSION OF SIRT1 MAY AFFECT THE TRANSCRIPTIONAL REGULATION MECHANISM AND SIGNALING PROTEIN ACETYLATION, AFFECTING NEUROPLASTICITY AND ULTIMATELY CONTRIBUTE TO MDD. IN THE STRESS-SUSCEPTIBLE MICE, THESE TWO MECHANISMS MAY CO-EXIST, BUT THE SPECIFIC MECHANISM NEEDS FURTHER RESEARCH. 2021 8 2452 29 EPIGENETIC SUPPRESSION OF POTASSIUM-CHLORIDE CO-TRANSPORTER 2 EXPRESSION IN INFLAMMATORY PAIN INDUCED BY COMPLETE FREUND'S ADJUVANT (CFA). BACKGROUND: MULTIPLE MECHANISMS CONTRIBUTE TO THE STIMULUS-EVOKED PAIN HYPERSENSITIVITY THAT MAY BE EXPERIENCED AFTER PERIPHERAL INFLAMMATION. PERSISTENT PATHOLOGICAL STIMULI IN MANY PAIN CONDITIONS AFFECT THE EXPRESSION OF CERTAIN GENES THROUGH EPIGENETIC ALTERNATIONS. THE MAIN PURPOSE OF OUR STUDY WAS TO INVESTIGATE THE ROLE OF EPIGENETIC MODIFICATION ON POTASSIUM-CHLORIDE CO-TRANSPORTER 2 (KCC2) GENE EXPRESSION IN THE PERSISTENCE OF INFLAMMATORY PAIN. METHODS: PERSISTENT INFLAMMATORY PAIN WAS INDUCED THROUGH THE INJECTION OF COMPLETE FREUND'S ADJUVANT (CFA) IN THE LEFT HIND PAW OF RATS. ACETYL-HISTONE H3 AND H4 LEVEL WAS DETERMINED BY CHROMATIN IMMUNOPRECIPITATION IN THE SPINAL DORSAL HORN. PAIN BEHAVIOUR AND INHIBITORY SYNAPTIC FUNCTION OF SPINAL CORD WERE DETERMINED BEFORE AND AFTER CFA INJECTION. KCC2 EXPRESSION WAS DETERMINED BY REAL TIME RT-PCR AND WESTERN BLOT. INTRATHECAL KCC2 SIRNA (2 MUG PER 10 MUL PER RAT) OR HDAC INHIBITOR (10 MUG PER 10 MUL PER RAT) WAS INJECTED ONCE DAILY FOR 3 DAYS BEFORE CFA INJECTION. RESULTS: PERSISTENT INFLAMMATORY PAIN EPIGENETICALLY SUPPRESSED KCC2 EXPRESSION THROUGH HISTONE DEACETYLASE (HDAC)-MEDIATED HISTONE HYPOACETYLATION, RESULTING IN DECREASED INHIBITORY SIGNALLING EFFICACY. KCC2 KNOCK-DOWN CAUSED BY INTRATHECAL ADMINISTRATION OF KCC2 SIRNA IN NAIVE RATS REDUCED KCC2 EXPRESSION IN THE SPINAL CORD, LEADING TO SENSITIZED PAIN BEHAVIOURS AND IMPAIRED INHIBITORY SYNAPTIC TRANSMISSION IN THEIR SPINAL CORDS. MOREOVER, INTRATHECAL HDAC INHIBITOR INJECTION IN CFA RATS INCREASED KCC2 EXPRESSION, PARTIALLY RESTORING THE SPINAL INHIBITORY SYNAPTIC TRANSMISSION AND RELIEVING THE SENSITIZED PAIN BEHAVIOUR. CONCLUSION: THESE FINDINGS SUGGEST THAT THE TRANSCRIPTION OF SPINAL KCC2 IS REGULATED BY HISTONE ACETYLATION EPIGENETICALLY FOLLOWING CFA. SIGNIFICANCE: PERSISTENT PAIN SUPPRESSES KCC2 EXPRESSION THROUGH HDAC-MEDIATED HISTONE HYPOACETYLATION AND CONSEQUENTLY IMPAIRS THE INHIBITORY FUNCTION OF INHIBITORY INTERNEURONS. DRUGS SUCH AS HDAC INHIBITORS THAT SUPPRESS THE INFLUENCES OF PERSISTENT PAIN ON THE EXPRESSION OF KCC2 MAY SERVE AS A NOVEL ANALGESIC. 2017 9 5679 35 SHORT- AND LONG-TERM HINDLIMB IMMOBILIZATION AND RELOADING: PROFILE OF EPIGENETIC EVENTS IN GASTROCNEMIUS. SKELETAL MUSCLE DYSFUNCTION AND ATROPHY ARE CHARACTERISTIC FEATURES ACCOMPANYING CHRONIC CONDITIONS. EPIGENETIC EVENTS REGULATE MUSCLE MASS AND FUNCTION MAINTENANCE. WE HYPOTHESIZED THAT THE PATTERN OF EPIGENETIC EVENTS (MUSCLE-ENRICHED MICRORNAS AND HISTONE ACETYLATION) AND ACETYLATION OF TRANSCRIPTION FACTORS KNOWN TO SIGNAL MUSCLE WASTING MAY DIFFER BETWEEN EARLY- AND LATE-TIME POINTS IN SKELETAL MUSCLES OF MICE EXPOSED TO HINDLIMB IMMOBILIZATION (I) AND RECOVERY FOLLOWING I. BODY AND MUSCLE WEIGHTS, GRIP STRENGTH, MUSCLE-ENRICHED MICRORNAS, HISTONE DEACETYLASES (HDACS), ACETYLATION OF PROTEINS, HISTONES, AND TRANSCRIPTION FACTORS (TF), MYOGENIC TF FACTORS, AND MUSCLE PHENOTYPE WERE ASSESSED IN GASTROCNEMIUS OF MICE EXPOSED TO PERIODS (1, 2, 3, 7, 15, AND 30 DAYS, I GROUPS) OF HINDLIMB IMMOBILIZATION, AND IN THOSE EXPOSED TO RELOADING FOR DIFFERENT PERIODS OF TIME (1, 3, 7, 15, AND 30 DAYS, R GROUPS) FOLLOWING 7-DAY IMMOBILIZATION. COMPARED TO NON-IMMOBILIZED CONTROLS, MUSCLE WEIGHT, LIMB STRENGTH, MICRORNAS, ESPECIALLY MIR-486, SIRT1 LEVELS, AND SLOW- AND FAST-TWITCH CROSS-SECTIONAL AREAS WERE DECREASED IN MICE OF I GROUPS, WHEREAS PAX7 AND ACETYLATED FOXO1 AND FOXO3 LEVELS WERE INCREASED. MUSCLE RELOADING FOLLOWING SPLINT REMOVAL IMPROVED MUSCLE MASS LOSS, STRENGTH, AND FIBER ATROPHY, BY INCREASING MICRORNAS, PARTICULARLY MIR-486, AND SIRT1 CONTENT, WHILE DECREASING ACETYLATED FOXO1 AND FOXO3 LEVELS. IN THIS MOUSE MODEL OF DISUSE MUSCLE ATROPHY, MUSCLE-ENRICHED MICRORNAS, ESPECIALLY MIR-486, THROUGH PAX7 REGULATION DELAYED MUSCLE CELL DIFFERENTIATION FOLLOWING UNLOADING OF GASTROCNEMIUS MUSCLE. ACETYLATION OF FOXO1 AND 3 SEEMED TO DRIVE MUSCLE MASS LOSS AND ATROPHY, WHILE DEACETYLATION OF THESE FACTORS THROUGH SIRT1 WOULD ENABLE THE MUSCLE FIBERS TO REGENERATE. J. CELL. PHYSIOL. 232: 1415-1427, 2017. (C) 2016 WILEY PERIODICALS, INC. 2017 10 5781 37 SPINAL SIRT1 ACTIVATION ATTENUATES NEUROPATHIC PAIN IN MICE. ABNORMAL HISTONE ACETYLATION OCCURS DURING NEUROPATHIC PAIN THROUGH AN EPIGENETIC MECHANISM. SILENT INFORMATION REGULATOR 1 (SIR2 OR SIRT1), A NAD-DEPENDENT DEACETYLASE, PLAYS COMPLEX SYSTEMIC ROLES IN A VARIETY OF PROCESSES THROUGH DEACETYLATING ACETYLATED HISTONE AND OTHER SPECIFIC SUBSTRATES. BUT THE ROLE OF SIRT1 IN NEUROPATHIC PAIN IS NOT WELL ESTABLISHED YET. THE PRESENT STUDY WAS INTENDED TO DETECT SIRT1 CONTENT AND ACTIVITY, NICOTINAMIDE (NAM) AND NICOTINAMIDE ADENINE DINUCLEOTIDE (NAD) IN THE SPINAL CORD USING IMMUNOBLOTTING OR MASS SPECTROSCOPY OVER TIME IN MICE FOLLOWING CHRONIC CONSTRICTION INJURY (CCI) OR SHAM SURGERY. IN ADDITION, THE EFFECT OF INTRATHECAL INJECTION OF NAD OR RESVERATROL ON THERMAL HYPERALGESIA AND MECHANICAL ALLODYNIA WAS EVALUATED IN CCI MICE. FINALLY, WE INVESTIGATED WHETHER SIRT1 INHIBITOR EX-527 COULD REVERSE THE ANTI-NOCICEPTIVE EFFECT OF NAD OR RESVERATROL. IT WAS FOUND THAT SPINAL SIRT1 EXPRESSION, DEACETYLASE ACTIVITY AND NAD/NAM DECREASED SIGNIFICANTLY 1, 3, 7, 14 AND 21 DAYS AFTER CCI SURGERY AS COMPARED WITH SHAM GROUP. IN ADDITION, DAILY INTRATHECAL INJECTION OF 5 MICROL 800 MM NAD 1 H BEFORE AND 1 DAY AFTER CCI SURGERY OR SINGLE INTRATHECAL INJECTION OF 5 MICROL 90 MM RESVERATROL 1 H BEFORE CCI SURGERY PRODUCED A TRANSIENT INHIBITORY EFFECT ON THERMAL HYPERALGESIA AND MECHANICAL ALLODYNIA IN CCI MICE. FINALLY, AN INTRATHECAL INJECTION OF 5 MICROL 1.2 MM EX-527 1 H BEFORE NAD OR RESVERATROL ADMINISTRATION REVERSED THE ANTI-NOCICEPTIVE EFFECT OF NAD OR RESVERATROL. THESE DATA INDICATE THAT THE REDUCTION IN SIRT1 DEACETYLASE ACTIVITY MAY BE A FACTOR CONTRIBUTING TO THE DEVELOPMENT OF NEUROPATHIC PAIN IN CCI MICE. OUR FINDINGS SUGGEST THAT THE ENHANCEMENT OF SPINAL NAD/NAM AND/OR SIRT1 ACTIVITY MAY BE A POTENTIALLY PROMISING STRATEGY FOR THE PREVENTION OR TREATMENT OF NEUROPATHIC PAIN. 2014 11 1126 38 COMPLEX REGULATION OF THE REGULATOR OF SYNAPTIC PLASTICITY HISTONE DEACETYLASE 2 IN THE RODENT DORSAL HORN AFTER PERIPHERAL INJURY. HISTONE DEACETYLASES (HDACS), HDAC2 IN PARTICULAR, HAVE BEEN SHOWN TO REGULATE VARIOUS FORMS OF LEARNING AND MEMORY. SINCE COGNITIVE PROCESSES SHARE MECHANISMS WITH SPINAL NOCICEPTIVE SIGNALLING, WE DECIDED TO INVESTIGATE THE HDAC2 EXPRESSION IN THE DORSAL HORN AFTER PERIPHERAL INJURY. USING IMMUNOHISTOCHEMISTRY, WE FOUND THAT SPINAL HDAC2 WAS MAINLY SEEN IN NEURONS AND ASTROCYTES, WITH NEURONAL EXPRESSION IN NAIVE TISSUE 2.6 TIMES GREATER THAN THAT IN ASTROCYTES. CYSTEINE (S)-NITROSYLATION OF HDAC2 RELEASES HDAC2 GENE SILENCING AND IS CONTROLLED BY NITRIC OXIDE (NO). A DURATION OF 48 H AFTER INTRAPLANTAR INJECTION OF COMPLETE FREUND'S ADJUVANT, THERE WAS AN IPSILATERAL INCREASE IN THE MOST IMPORTANT NO-PRODUCING ENZYME IN PAIN STATES, NITRIC OXIDE SYNTHASE (NNOS), ACCOMPANIED BY AN INCREASE IN HDAC2 S-NITROSYLATION. MOREOVER, A SUBSET OF NNOS-POSITIVE NEURONS EXPRESSED CFOS, A KNOWN TARGET OF HDAC2, SUGGESTING THAT DEREPRESSION OF CFOS EXPRESSION FOLLOWING HDAC2 S-NITROSYLATION MIGHT OCCUR AFTER NOXIOUS STIMULATION. WE SAW NO CHANGE IN GLOBAL HDAC2 EXPRESSION IN BOTH SHORT- AND LONG-TERM PAIN STATES. HOWEVER, HDAC2 WAS INCREASED IN ASTROCYTES 7 DAYS AFTER NEUROPATHIC INJURY SUGGESTING THAT HDAC2 MIGHT INHIBIT ASTROCYTIC GENE EXPRESSION IN NEUROPATHIC PAIN STATES. ALL TOGETHER, OUR RESULTS INDICATE THAT THE EPIGENETIC REGULATION OF TRANSCRIPTIONAL PROGRAMMES IN THE DORSAL HORN AFTER INJURY IS CELL SPECIFIC. MOREOVER, THE PROMINENT ROLE OF NO IN PERSISTENT PAIN STATES SUGGESTS THAT HDAC2 S-NITROSYLATION COULD PLAY A CRUCIAL ROLE IN THE REGULATION OF GENE EXPRESSION LEADING TO HYPERSENSITIVITY. OUR MANUSCRIPT DESCRIBES FOR THE FIRST TIME THE REGULATION OF THE MEMORY REGULATOR HISTONE DEACETYLASE 2 (HDAC2) IN THE SUPERFICIAL DORSAL HORN OF ADULT RATS FOLLOWING PERIPHERAL INJURY. OUR CELL-SPECIFIC APPROACH HAS REVEALED A COMPLEX PATTERN OF EXPRESSION OF SPINAL HDAC2 THAT DEPENDS ON THE INJURY AND THE CELL TYPE, SUGGESTING A SOPHISTICATED REGULATION OF GENE EXPRESSION BY HDAC2. 2016 12 3331 34 HISTONE DEACETYLASE INHIBITOR SUBERANILOHYDROXAMIC ACID TREATMENT REVERSES HYPOSENSITIVITY TO GAMMA-AMINOBUTYRIC ACID IN THE VENTRAL TEGMENTAL AREA DURING ETHANOL WITHDRAWAL. BACKGROUND: THE VENTRAL TEGMENTAL AREA (VTA) IS IMPORTANT FOR ALCOHOL-RELATED REWARD AND REINFORCEMENT. MOUSE VTA NEURONS ARE HYPOSENSITIVE TO GAMMA-AMINOBUTYRIC ACID (GABA) DURING ETHANOL (ETOH) WITHDRAWAL, AND GABA RESPONSIVENESS IS NORMALIZED BY IN VITRO TREATMENT WITH HISTONE DEACETYLASE INHIBITORS (HDACI). THE PRESENT STUDY EXAMINED THE EFFECT OF A SYSTEMICALLY ADMINISTERED HDACI, SUBERANILOHYDROXAMIC ACID (SAHA) ON GABA SENSITIVITY, AND RELATED MOLECULAR CHANGES IN VTA NEURONS DURING WITHDRAWAL AFTER CHRONIC ETOH INTAKE IN RATS. METHODS: SPRAGUE DAWLEY MALE ADULT RATS WERE FED WITH LIEBER-DECARLI DIET (9% ETOH OR CONTROL DIET) FOR 16 DAYS. EXPERIMENTAL GROUPS INCLUDED CONTROL DIET-FED AND ETOH DIET-FED (0- OR 24-HOUR WITHDRAWAL) RATS TREATED WITH EITHER SAHA OR VEHICLE INJECTION. SINGLE-UNIT RECORDINGS WERE USED TO MEASURE THE RESPONSE OF VTA NEURONS TO GABA. IMMUNOHISTOCHEMISTRY WAS PERFORMED TO EXAMINE LEVELS OF HDAC2, ACETYLATED HISTONE H3 LYSINE 9 (ACH3K9), AND GABA(A) RECEPTOR ALPHA1 AND ALPHA5 SUBUNITS IN THE VTA; QUANTITATIVE POLYMERASE CHAIN REACTION WAS PERFORMED TO EXAMINE THE MRNA LEVELS OF HDAC2 AND GABA(A) RECEPTOR SUBUNITS. RESULTS: VTA NEURONS FROM THE WITHDRAWAL GROUP EXHIBITED GABA HYPOSENSITIVITY. IN VIVO SAHA TREATMENT 2 HOURS BEFORE SACRIFICE NORMALIZED THE SENSITIVITY OF VTA NEURONS TO GABA. ETOH WITHDRAWAL WAS ASSOCIATED WITH INCREASED HDAC2 AND DECREASED ACH3K9 PROTEIN LEVELS; SAHA TREATMENT NORMALIZED ACH3K9 LEVELS. INTERESTINGLY, NO SIGNIFICANT CHANGE WAS OBSERVED IN THE MRNA LEVELS OF HDAC2. THE MRNA LEVELS, BUT NOT PROTEIN LEVELS, OF GABA(A) RECEPTOR ALPHA1 AND ALPHA5 SUBUNITS WERE INCREASED DURING WITHDRAWAL. CONCLUSIONS: WITHDRAWAL FROM CHRONIC ETOH EXPOSURE RESULTS IN A DECREASE IN GABA-MEDIATED INHIBITION, AND THIS GABA HYPOSENSITIVITY IS NORMALIZED BY IN VIVO SAHA TREATMENT. DISRUPTION OF SIGNALING IN THE VTA PRODUCED BY ALTERATION OF GABA NEUROTRANSMISSION COULD BE 1 NEUROADAPTIVE PHYSIOLOGICAL PROCESS LEADING TO CRAVING AND RELAPSE. THESE RESULTS SUGGEST THAT HDACI PHARMACOTHERAPY WITH AGENTS LIKE SAHA MIGHT BE AN EFFECTIVE TREATMENT FOR ALCOHOLISM. 2018 13 4172 26 MELATONIN IMPEDES TET1-DEPENDENT MGLUR5 PROMOTER DEMETHYLATION TO RELIEVE PAIN. MELATONIN (N-ACETYL-5-METHOXYTRYPTAMINE)/MT2 RECEPTOR-DEPENDENT EPIGENETIC MODIFICATION REPRESENTS A NOVEL PATHWAY IN THE TREATMENT OF NEUROPATHIC PAIN. BECAUSE SPINAL TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE 1 (TET1)-DEPENDENT EPIGENETIC DEMETHYLATION HAS RECENTLY BEEN LINKED TO PAIN HYPERSENSITIVITY, WE HYPOTHESIZED THAT MELATONIN/MT2-DEPENDENT ANALGESIA INVOLVES SPINAL TET1-DEPENDENT DEMETHYLATION. HERE, WE SHOWED THAT SPINAL TET1 GENE TRANSFER BY INTRATHECAL DELIVERY OF TET1-ENCODING VECTORS TO NAIVE RATS PRODUCED PROFOUND AND LONG-LASTING NOCICEPTIVE HYPERSENSITIVITY. IN ADDITION, ENHANCED TET1 EXPRESSION, TET1-METABOTROPIC GLUTAMATE RECEPTOR SUBTYPE 5 (MGLUR5) PROMOTER COUPLING, DEMETHYLATION AT THE MGLUR5 PROMOTER, AND MGLUR5 EXPRESSION IN DORSAL HORN NEURONS WERE OBSERVED. RATS SUBJECTED TO SPINAL NERVE LIGATION AND INTRAPLANTAR COMPLETE FREUND'S ADJUVANT INJECTION DISPLAYED TACTILE ALLODYNIA AND BEHAVIORAL HYPERALGESIA ASSOCIATED WITH SIMILAR CHANGES IN THE DORSAL HORN. NOTABLY, INTRATHECAL MELATONIN INJECTION REVERSED THE PROTEIN EXPRESSION, PROTEIN-PROMOTER COUPLING, PROMOTER DEMETHYLATION, AND PAIN HYPERSENSITIVITY INDUCED BY TET1 GENE TRANSFER, SPINAL NERVE LIGATION, AND INTRAPLANTAR COMPLETE FREUND'S ADJUVANT INJECTION. ALL THE EFFECTS CAUSED BY MELATONIN WERE BLOCKED BY PRETREATMENT WITH A MT2 RECEPTOR-SELECTIVE ANTAGONIST. IN CONCLUSION, MELATONIN RELIEVES PAIN BY IMPEDING TET1-DEPENDENT DEMETHYLATION OF MGLUR5 IN DORSAL HORN NEURONS THROUGH THE MT2 RECEPTOR. OUR FINDINGS LINK MELATONIN/MT2 SIGNALING TO TET1-DEPENDENT EPIGENETIC DEMETHYLATION OF NOCICEPTIVE GENES FOR THE FIRST TIME AND SUGGEST MELATONIN AS A PROMISING THERAPY FOR THE TREATMENT OF PAIN. 2017 14 3869 36 JNK1 REGULATES HISTONE ACETYLATION IN TRIGEMINAL NEURONS FOLLOWING CHEMICAL STIMULATION. TRIGEMINAL NERVE FIBERS IN NASAL AND ORAL CAVITIES ARE SENSITIVE TO VARIOUS ENVIRONMENTAL HAZARDOUS STIMULI, WHICH TRIGGER MANY NEUROTOXIC PROBLEMS SUCH AS CHRONIC MIGRAINE HEADACHE AND TRIGEMINAL IRRITATED DISORDERS. HOWEVER, THE ROLE OF JNK KINASE CASCADE AND ITS EPIGENETIC MODULATION OF HISTONE REMODELING IN TRIGEMINAL GANGLION (TG) NEURONS ACTIVATED BY ENVIRONMENTAL NEUROTOXINS REMAINS UNKNOWN. HERE WE INVESTIGATED THE ROLE OF JNK/C-JUN CASCADE IN THE REGULATION OF ACETYLATION OF H3 HISTONE IN TG NEURONS FOLLOWING IN VITRO STIMULATION BY A NEURO-INFLAMMATORY AGENT, MUSTARD OIL (MO). WE FOUND THAT MO STIMULATION ELICITED JNK/C-JUN PATHWAY SIGNIFICANTLY BY ENHANCING PHOSPHO-JNK1, PHOSPHO-C-JUN EXPRESSION, AND C-JUN ACTIVITY, WHICH WERE CORRELATED WITH AN ELEVATED ACETYLATED H3 HISTONE IN TG NEURONS. HOWEVER, INCREASES IN PHOSPHO-C-JUN AND C-JUN ACTIVITY WERE SIGNIFICANTLY BLOCKED BY A JNK INHIBITOR, SP600125. WE ALSO FOUND THAT ALTERED H3 HISTONE REMODELING, ASSESSED BY H3 ACETYLATION IN TRIGGERED TG NEURONS, WAS REDUCED BY SP600125. THE STUDY SUGGESTS THAT THE ACTIVATED JNK SIGNALING IN REGULATION OF HISTONE REMODELING MAY CONTRIBUTE TO NEURO-EPIGENTIC CHANGES IN PERIPHERAL SENSORY NEURONS FOLLOWING ENVIRONMENTAL NEUROTOXIC EXPOSURE. 2008 15 2866 31 FUNCTIONAL ADULT ACETYLCHOLINE RECEPTOR DEVELOPS INDEPENDENTLY OF MOTOR INNERVATION IN SOL 8 MOUSE MUSCLE CELL LINE. WE HAVE DEFINED CULTURE CONDITIONS, USING A FEEDER LAYER OF CELLS FROM THE EMBRYONIC MESENCHYMAL CELL LINE, 10T1/2 AND A SERUM-FREE MEDIUM, WHICH ALLOW CELLS FROM THE MOUSE MYOGENIC CELL LINE SOL 8 TO FORM CONTRACTING MYOTUBES FOR TWO WEEKS. UNDER THESE CULTURE CONDITIONS, SOL 8 MYOTUBES UNDERGO A MATURATION PROCESS CHARACTERIZED BY A SEQUENTIAL EXPRESSION OF TWO PHENOTYPES. AN EARLY PHENOTYPE IS TYPIFIED BY THE EXPRESSION OF THE NICOTINIC ACETYLCHOLINE RECEPTOR (ACHR) GAMMA-SUBUNIT TRANSCRIPTS AND THE PRESENCE OF LOW CONDUCTANCE ACH-ACTIVATED CHANNELS, TYPICAL OF EMBRYONIC ACHR. A LATE PHENOTYPE IS CHARACTERIZED BY THE EXPRESSION OF ACHR EPSILON-SUBUNIT TRANSCRIPTS, THE DECREASED ACCUMULATION OF GAMMA-SUBUNIT TRANSCRIPTS AND THE APPEARANCE OF HIGH CONDUCTANCE ACH-ACTIVATED CHANNELS, TYPICAL OF ADULT ACHR. THESE RESULTS INDICATE THAT THE EXPRESSION OF FUNCTIONAL ADULT TYPE ACHR DOES NOT REQUIRE THE PRESENCE OF THE MOTOR NERVE AND THEREFORE REPRESENTS AN INTRINSIC FEATURE OF THE SOL 8 MUSCLE CELLS. CHRONIC EXPOSURE OF THE CELLS TO THE VOLTAGE-SENSITIVE NA+ CHANNEL BLOCKING AGENT TETRODOTOXIN DOES NOT AFFECT THE APPEARANCE OF THE ACHR EPSILON-SUBUNIT TRANSCRIPTS BUT PREVENTS THE REDUCTION OF THE STEADY-STATE LEVEL OF THE ACHR GAMMA-SUBUNIT TRANSCRIPTS AND YIELDS A REDUCED PROPORTION OF THE ADULT TYPE CHANNELS. THUS, ACTIVITY SEEMS TO FACILITATE THE SWITCH FROM THE EMBRYONIC TO THE ADULT PHENOTYPE OF THE ACHR PROTEIN. THE SOL 8 CELL SYSTEM MIGHT BE USEFUL TO ANALYSE FURTHER THE GENETIC AND EPIGENETIC REGULATION OF MUSCLE FIBRE MATURATION IN MAMMALS. 1991 16 2300 34 EPIGENETIC REGULATION OF BDNF EXPRESSION IN THE PRIMARY SENSORY NEURONS AFTER PERIPHERAL NERVE INJURY: IMPLICATIONS IN THE DEVELOPMENT OF NEUROPATHIC PAIN. BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) IS KNOWN TO BE UP-REGULATED IN THE DORSAL ROOT GANGLION (DRG) AFTER PERIPHERAL NERVE INJURY, AND TO CONTRIBUTE TO NEUROPATHIC PAIN. HERE, WE FOUND THAT THERMAL HYPERALGESIA AND MECHANICAL ALLODYNIA AT DAY 7 POST-INJURY WERE INHIBITED ONLY WHEN ANTI-BDNF ANTIBODY WAS INTRATHECALLY ADMINISTRATED AT DAY 2 POST-INJURY. CONSISTENT WITH BEHAVIORAL RESULTS, WESTERN BLOT ANALYSIS SHOWED THAT THE EXPRESSION LEVELS OF BDNF PROTEIN IN THE SPINAL DORSAL HORN WERE MARKEDLY INDUCED DURING EARLY STAGE POST-INJURY. MOREOVER, THE MAXIMAL INCREASE IN BDNF MRNA EXPRESSION IN THE DRG WAS OBSERVED AT DAY 1 POST-INJURY, AND SIGNIFICANTLY ELEVATED LEVELS WERE SUSTAINED FOR AT LEAST 14 DAYS. FOUR OF FIVE BDNF MRNA TRANSCRIPTS WERE UP-REGULATED AFTER NERVE INJURY, AND THE MOST INDUCIBLE TRANSCRIPT WAS EXON I. USING A CHROMATIN IMMUNOPRECIPITATION (CHIP) ASSAY, WE FOUND THAT NERVE INJURY PROMOTES HISTONE H3 AND H4 ACETYLATION, TRANSCRIPTIONALLY ACTIVE MODIFICATIONS, AT BDNF PROMOTER I AT DAY 1 POST-INJURY, AND THE LEVELS OF HISTONE ACETYLATION REMAIN ELEVATED FOR AT LEAST 7 DAYS. TAKEN TOGETHER, OUR FINDINGS SUGGEST THAT AN INITIAL INCREASE IN BDNF EXON I EXPRESSION CONTROLLED BY EPIGENETIC MECHANISMS MIGHT HAVE A CRUCIAL ROLE IN THE DEVELOPMENT OF NEUROPATHIC PAIN. 2013 17 1320 42 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 18 742 35 CANNABINOID CB2 RECEPTORS ARE UPREGULATED VIA BIVALENT HISTONE MODIFICATIONS AND CONTROL PRIMARY AFFERENT INPUT TO THE SPINAL CORD IN NEUROPATHIC PAIN. TYPE-2 CANNABINOID RECEPTORS (CB2, ENCODED BY THE CNR2 GENE) ARE MAINLY EXPRESSED IN IMMUNE CELLS, AND CB2 AGONISTS NORMALLY HAVE NO ANALGESIC EFFECT. HOWEVER, NERVE INJURY UPREGULATES CB2 IN THE DORSAL ROOT GANGLION (DRG), FOLLOWING WHICH CB2 STIMULATION REDUCES NEUROPATHIC PAIN. IT IS UNCLEAR HOW NERVE INJURY INCREASES CB2 EXPRESSION OR HOW CB2 ACTIVITY IS TRANSFORMED IN NEUROPATHIC PAIN. IN THIS STUDY, IMMUNOBLOTTING SHOWED THAT SPINAL NERVE LIGATION (SNL) INDUCED A DELAYED AND SUSTAINED INCREASE IN CB2 EXPRESSION IN THE DRG AND DORSAL SPINAL CORD SYNAPTOSOMES. RNASCOPE IN SITU HYBRIDIZATION ALSO SHOWED THAT SNL SUBSTANTIALLY INCREASED CB2 MRNA LEVELS, MOSTLY IN MEDIUM AND LARGE DRG NEURONS. FURTHERMORE, WE FOUND THAT THE SPECIFIC CB2 AGONIST JWH-133 SIGNIFICANTLY INHIBITS THE AMPLITUDE OF DORSAL ROOT-EVOKED GLUTAMATERGIC EXCITATORY POSTSYNAPTIC CURRENTS IN SPINAL DORSAL HORN NEURONS IN SNL RATS, BUT NOT IN SHAM CONTROL RATS; INTRATHECAL INJECTION OF JWH-133 REVERSED PAIN HYPERSENSITIVITY IN SNL RATS, BUT HAD NO EFFECT IN SHAM CONTROL RATS. IN ADDITION, CHROMATIN IMMUNOPRECIPITATION-QPCR ANALYSIS SHOWED THAT SNL INCREASED ENRICHMENT OF TWO ACTIVATING HISTONE MARKS (H3K4ME3 AND H3K9AC) AND DIMINISHED OCCUPANCY OF TWO REPRESSIVE HISTONE MARKS (H3K9ME2 AND H3K27ME3) AT THE CNR2 PROMOTER IN THE DRG. IN CONTRAST, SNL HAD NO EFFECT ON DNA METHYLATION LEVELS AROUND THE CNR2 PROMOTER. OUR FINDINGS SUGGEST THAT PERIPHERAL NERVE INJURY PROMOTES CB2 EXPRESSION IN PRIMARY SENSORY NEURONS VIA EPIGENETIC BIVALENT HISTONE MODIFICATIONS AND THAT CB2 ACTIVATION REDUCES NEUROPATHIC PAIN BY ATTENUATING NOCICEPTIVE TRANSMISSION FROM PRIMARY AFFERENT NERVES TO THE SPINAL CORD. 2022 19 3832 27 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 5708 40 SIRT1 ATTENUATES NEUROPATHIC PAIN BY EPIGENETIC REGULATION OF MGLUR1/5 EXPRESSIONS IN TYPE 2 DIABETIC RATS. ACCUMULATING EVIDENCE HAS DEMONSTRATED THAT EPIGENETIC MODIFICATION-MEDIATED CHANGES IN PAIN-RELATED GENE EXPRESSIONS PLAY AN IMPORTANT ROLE IN THE DEVELOPMENT AND MAINTENANCE OF NEUROPATHIC PAIN. SIRTUIN 1 (SIRT1), A NICOTINAMIDE ADENINE DINUCLEOTIDE (NAD)-DEPENDENT DEACETYLASE, IS INVOLVED IN THE DEVELOPMENT OF CHRONIC PAIN. MOREOVER, SIRT1 MAY BE A NOVEL THERAPEUTIC TARGET FOR THE PREVENTION OF TYPE 2 DIABETES MELLITUS (T2DM). BUT THE ROLE OF SIRT1 IN T2DM-INDUCED NEUROPATHIC PAIN REMAINS UNKNOWN. IN THIS STUDY, WE FOUND THAT SPINAL SIRT1 EXPRESSION AND ACTIVITY WERE DOWNREGULATED SIGNIFICANTLY IN HIGH-FAT-FED/LOW-DOSE STREPTOZOTOCIN-INDUCED NEUROPATHIC PAIN RATS. SIRT1 LOCALIZED IN SPINAL NEURONS BUT NOT IN ASTROCYTES OR MICROGLIA. FURTHERMORE, THE EXPRESSIONS OF METABOTROPIC GLUTAMATE RECEPTOR (MGLUR1) AND MGLUR5, WHICH PLAY A KEY ROLE IN CENTRAL SENSITIZATION AND NEUROPATHIC PAIN, AND H3 ACETYLATION LEVELS AT GRM1/5 (ENCODING MGLUR1/5) PROMOTER REGIONS WERE INCREASED IN DIABETIC NEUROPATHIC PAIN RATS. SIRT1 ACTIVATOR SRT1720 REVERSED THERMAL HYPERALGESIA AND MECHANICAL ALLODYNIA AND SPINAL NEURONAL ACTIVATION IN DIABETIC NEUROPATHIC PAIN RATS. CONCURRENTLY, INCREASED EXPRESSIONS OF MGLUR1/5 AND H3 ACETYLATION LEVELS AT GRM1/5 PROMOTER REGIONS WERE REVERSED BY SIRT1 ACTIVATION. IN ADDITION, KNOCKDOWN OF SIRT1 BY AD-SIRT1-SHRNA INDUCED PAIN BEHAVIORS AND SPINAL NEURONAL ACTIVATION IN NORMAL RATS, WHICH WAS ACCOMPANIED BY THE INCREASED EXPRESSIONS OF MGLUR1/5 AND H3 ACETYLATION LEVELS AT GRM1/5 PROMOTER REGIONS. THEREFORE, WE CONCLUDED THAT SIRT1-MEDIATED EPIGENETIC REGULATION OF MGLUR1/5 EXPRESSIONS WAS INVOLVED IN THE DEVELOPMENT OF NEUROPATHIC PAIN IN TYPE 2 DIABETIC RATS. 2017