1 6224 175 THE LEUCINE CATABOLITE AND DIETARY SUPPLEMENT BETA-HYDROXY-BETA-METHYL BUTYRATE (HMB) AS AN EPIGENETIC REGULATOR IN MUSCLE PROGENITOR CELLS. BETA-HYDROXY-BETA-METHYL BUTYRATE (HMB) IS A NATURAL CATABOLITE OF LEUCINE DEEMED TO PLAY A ROLE IN AMINO ACID SIGNALING AND THE MAINTENANCE OF LEAN MUSCLE MASS. ACCORDINGLY, HMB IS USED AS A DIETARY SUPPLEMENT BY SPORTSMEN AND HAS SHOWN SOME CLINICAL EFFECTIVENESS IN PREVENTING MUSCLE WASTING IN CANCER AND CHRONIC LUNG DISEASE, AS WELL AS IN AGE-DEPENDENT SARCOPENIA. HOWEVER, THE MOLECULAR CASCADES UNDERLYING THESE BENEFICIAL EFFECTS ARE LARGELY UNKNOWN. HMB BEARS A SIGNIFICANT STRUCTURAL SIMILARITY WITH BUTYRATE AND BETA-HYDROXYBUTYRATE (BETAHB), TWO COMPOUNDS RECOGNIZED FOR IMPORTANT EPIGENETIC AND HISTONE-MARKING ACTIVITIES IN MULTIPLE CELL TYPES INCLUDING MUSCLE CELLS. WE ASKED WHETHER SIMILAR CHROMATIN-MODIFYING ACTIONS COULD BE ASSIGNED TO HMB AS WELL. EXPOSURE OF MURINE C2C12 MYOBLASTS TO MILLIMOLAR CONCENTRATIONS OF HMB LED TO AN INCREASE IN GLOBAL HISTONE ACETYLATION, AS MONITORED BY ANTI-ACETYLATED LYSINE IMMUNOBLOTTING, WHILE PREVENTING MYOTUBE DIFFERENTIATION. IN THESE EFFECTS, HMB RESEMBLED, ALTHOUGH WITH LESS POTENCY, THE HISTONE DEACETYLASE (HDAC) INHIBITOR SODIUM BUTYRATE. HOWEVER, INITIAL STUDIES DID NOT CONFIRM A DIRECT INHIBITORY EFFECT OF HMB ON HDACS IN VITRO. BETA-HYDROXYBUTYRATE, A KETONE BODY PRODUCED BY THE LIVER DURING STARVATION OR INTENSE EXERCISE, HAS A MODEST EFFECT ON HISTONE ACETYLATION OF C2C12 CELLS OR IN VITRO HDAC INHIBITOR ACTIVITIES, AND, UNLIKE BUTYRATE AND HMB, DID NOT INTERFERE WITH MYOTUBE FORMATION IN A MYOBLAST DIFFERENTIATION ASSAY. INSTEAD, BETAHB DRAMATICALLY INCREASED LYSINE BETA-HYDROXYBUTYRYLATION (KBHB) OF HISTONE TAILS, AN EPIGENETIC MARK ASSOCIATED WITH FASTING RESPONSES AND MUSCLE CATABOLIC STATES. HOWEVER, WHEN C2C12 CELLS WERE EXPOSED TO BETAHB IN THE PRESENCE OF EQUIMOLAR HMB THIS CHROMATIN MODIFICATION WAS DRASTICALLY REDUCED, POINTING TO A ROLE FOR HMB IN ATTENUATING KETOSIS-ASSOCIATED MUSCLE WASTING. IN CONCLUSION, WHILE THEIR MECHANISTIC UNDERPINNINGS REMAIN TO BE CLARIFIED, THESE PRELIMINARY OBSERVATIONS HIGHLIGHT NOVEL AND POTENTIALLY IMPORTANT ACTIVITIES OF HMB AS AN EPIGENETIC REGULATOR AND BETAHB ANTAGONIST IN MUSCLE PRECURSOR CELLS, TO BE FURTHER EXPLORED IN THEIR BIOMEDICAL IMPLICATIONS. 2021 2 3882 30 KETONE BODIES AS METABOLITES AND SIGNALLING MOLECULES AT THE CROSSROAD BETWEEN INFLAMMATION AND EPIGENETIC CONTROL OF CARDIOMETABOLIC DISORDERS. FOR MANY YEARS, IT HAS BEEN CLEAR THAT A WESTERN DIET RICH IN SATURATED FATS AND SUGARS PROMOTES AN INFLAMMATORY ENVIRONMENT PREDISPOSING A PERSON TO CHRONIC CARDIOMETABOLIC DISEASES. IN PARALLEL, THE EMERGENCE OF KETOGENIC DIETS, DEPRIVED OF CARBOHYDRATES AND PROMOTING THE SYNTHESIS OF KETONE BODIES IMITATING THE METABOLIC EFFECTS OF FASTING, HAS BEEN SHOWN TO PROVIDE A POSSIBLE NUTRITIONAL SOLUTION TO ALLEVIATING DISEASES TRIGGERED BY AN INFLAMMATORY ENVIRONMENT. THE MAIN KETONE BODY, BETA-HYDROXYBUTYRATE (BHB), ACTS AS AN ALTERNATIVE FUEL, AND ALSO AS A SUBSTRATE FOR A NOVEL HISTONE POST-TRANSLATIONAL MODIFICATION, BETA-HYDROXYBUTYRYLATION. BETA-HYDROXYBUTYRYLATION INFLUENCES THE STATE OF CHROMATIN ARCHITECTURE AND PROMOTES THE TRANSCRIPTION OF MULTIPLE GENES. BHB HAS ALSO BEEN SHOWN TO MODULATE INFLAMMATION IN CHRONIC DISEASES. IN THIS REVIEW, WE DISCUSS, IN THE PATHOLOGICAL CONTEXT OF CARDIOVASCULAR RISKS, THE CURRENT UNDERSTANDING OF HOW KETONE BODIES, OR A KETOGENIC DIET, ARE ABLE TO MODULATE, TRIGGER, OR INHIBIT INFLAMMATION AND HOW THE EPIGENOME AND CHROMATIN REMODELING MAY BE A KEY CONTRIBUTOR. 2022 3 2311 36 EPIGENETIC REGULATION OF CYTOSOLIC PHOSPHOLIPASE A2 IN SH-SY5Y HUMAN NEUROBLASTOMA CELLS. GROUP IVA CYTOSOLIC PHOSPHOLIPASE A2 (CPLA2 OR PLA2G4A) IS A KEY ENZYME THAT CONTRIBUTES TO INFLAMMATION VIA THE GENERATION OF ARACHIDONIC ACID AND EICOSANOIDS. WHILE MUCH IS KNOWN ABOUT REGULATION OF CPLA2 BY POSTTRANSLATIONAL MODIFICATION SUCH AS PHOSPHORYLATION, LITTLE IS KNOWN ABOUT ITS EPIGENETIC REGULATION. IN THIS STUDY, TREATMENT WITH HISTONE DEACETYLASE (HDAC) INHIBITORS, TRICHOSTATIN A (TSA), VALPROIC ACID, TUBACIN AND THE CLASS I HDAC INHIBITOR, MS-275, WERE FOUND TO INCREASE CPLA2ALPHA MESSENGER RNA (MRNA) EXPRESSION IN SH-SY5Y HUMAN NEUROBLASTOMA CELLS. CO-TREATMENT OF THE HISTONE ACETYLTRANSFERASE (HAT) INHIBITOR, ANACARDIC ACID, MODULATED UPREGULATION OF CPLA2ALPHA INDUCED BY TSA. SPECIFIC INVOLVEMENT OF CLASS I HDACS AND HAT IN CPLA2ALPHA REGULATION WAS FURTHER SHOWN, AND A TIP60-SPECIFIC HAT INHIBITOR, NU9056, MODULATED THE UPREGULATION OF CPLA2ALPHA INDUCED BY MS-275. IN ADDITION, CO-TREATMENT OF WITH HISTONE METHYLTRANSFERASE (HMT) INHIBITOR, 5'-DEOXY-5'-METHYLTHIOADENOSINE (MTA) SUPPRESSED TSA-INDUCED CPLA2ALPHA UPREGULATION. THE ABOVE CHANGES IN CPLA2 MRNA EXPRESSION WERE REFLECTED AT THE PROTEIN LEVEL BY WESTERN BLOTS AND IMMUNOCYTOCHEMISTRY. CHROMATIN IMMUNOPRECIPITATION (CHIP) SHOWED TSA INCREASED BINDING OF TRIMETHYLATED H3K4 TO THE PROXIMAL PROMOTER REGION OF THE CPLA2ALPHA GENE. CELL INJURY AFTER TSA TREATMENT AS INDICATED BY LACTATE DEHYDROGENASE (LDH) RELEASE WAS MODULATED BY ANACARDIC ACID, AND A ROLE OF CPLA2 IN MEDIATING TSA-INDUCED INJURY SHOWN, AFTER CO-INCUBATION WITH THE CPLA2 SELECTIVE INHIBITOR, ARACHIDONOYL TRIFLUOROMETHYL KETONE (AACOCF3). TOGETHER, RESULTS INDICATE EPIGENETIC REGULATION OF CPLA2 AND THE POTENTIAL OF SUCH REGULATION FOR TREATMENT OF CHRONIC INFLAMMATION. 2016 4 6283 29 THE POTENTIAL OF A KETOGENIC DIET TO MINIMIZE EFFECTS OF THE METABOLIC FAULT IN GLYCOGEN STORAGE DISEASE V AND VII. PURPOSE OF REVIEW: TO EXPLORE THE POTENTIAL OF A LOW CARBOHYDRATE KETOGENIC DIET (LCKD) TO COUNTER PHYSICAL ACTIVITY INTOLERANCE, PAIN AND MUSCLE DAMAGE FOR GLYCOGEN STORAGE DISEASE (GSD) V AND VII, AND HIGHLIGHT THE REALISTIC POSSIBILITY THAT NUTRITION COULD BE KEY. RECENT FINDINGS: CARBOHYDRATE (CHO) INGESTION DURING PHYSICAL ACTIVITY IN GSDV AND A LCKD FOR GSDVII IS COMMON. FOR THE LATTER, A LONG-TERM STUDY DEMONSTRATED IMPROVEMENT IN PHYSIOLOGICAL MARKERS WHILE ON A LCKD. THIS INCLUDED IMPROVEMENT IN AEROBIC POWER AND ACTIVITY TOLERANCE. IN GSDV, PRELIMINARY RESEARCH ON A LCKD SUGGEST A DIET OF 75% FAT, 15% PROTEIN, 10% CHO, IS BEST FOR IMPROVED FUNCTION AND COMPLIANCE. KETONES PROVIDE IMMEDIATE FUEL FOR ACUTE PHYSICAL ACTIVITY, AND HAVE AN EPIGENETIC ROLE, IMPROVING KETONE AND LIPID USE. EVIDENCE FROM ELITE ATHLETES FOUND A LCKD CAN INCREASE FAT OXIDATION AND IS OPTIMAL AT 70% VO2MAX. THIS SUGGESTS THE NEED TO ALSO IMPROVE CONDITIONING VIA EXERCISE TO MAXIMIZE THE BENEFIT OF A LCKD. SUMMARY: A HIGH CHO DIET IN GSDV AND VII COMES WITH A RESTRICTED PHYSICAL ACTIVITY CAPACITY ALONGSIDE SIGNIFICANT PAIN, MUSCLE DAMAGE AND RISK OF RENAL FAILURE. MOUNTING EVIDENCE SUGGESTS A LCKD IS EFFICACIOUS FOR BOTH DISORDERS PROVIDING AN IMMEDIATE FUEL SOURCE WHICH MAY NEGATE THE NEED FOR A 'WARM-UP' PRIOR TO EVERY ACTIVITY AND RESTORE 'NORMAL' FUNCTION. 2020 5 1038 37 CLINACANTHUS NUTANS EXTRACTS MODULATE EPIGENETIC LINK TO CYTOSOLIC PHOSPHOLIPASE A2 EXPRESSION IN SH-SY5Y CELLS AND PRIMARY CORTICAL NEURONS. CLINACANTHUS NUTANS LINDAU (C. NUTANS), COMMONLY KNOWN AS SABAH SNAKE GRASS IN SOUTHEAST ASIA, IS WIDELY USED IN FOLK MEDICINE DUE TO ITS ANALGESIC, ANTIVIRAL, AND ANTI-INFLAMMATORY PROPERTIES. OUR RECENT STUDY PROVIDED EVIDENCE FOR THE REGULATION OF CYTOSOLIC PHOSPHOLIPASE A2 (CPLA2) MRNA EXPRESSION BY EPIGENETIC FACTORS (TAN ET AL. IN MOL NEUROBIOL. DOI: 10.1007/S12035-015-9314-Z , 2015). THIS ENZYME CATALYZES THE RELEASE OF ARACHIDONIC ACID FROM GLYCEROPHOSPHOLIPIDS, AND FORMATION OF PRO-INFLAMMATORY EICOSANOIDS OR TOXIC LIPID PEROXIDATION PRODUCTS SUCH AS 4-HYDROXYNONENAL. IN THIS STUDY, WE EXAMINED THE EFFECTS OF C. NUTANS ETHANOL LEAF EXTRACTS ON EPIGENETIC REGULATION OF CPLA2 MRNA EXPRESSION IN SH-SY5Y HUMAN NEUROBLASTOMA CELLS AND MOUSE PRIMARY CORTICAL NEURONS. C. NUTANS MODULATED INDUCTION OF CPLA2 EXPRESSION IN SH-SY5Y CELLS BY HISTONE DEACETYLASE (HDAC) INHIBITORS, MS-275, MC-1568, AND TSA. C. NUTANS EXTRACTS ALSO INHIBITED HISTONE ACETYLASE (HAT) ACTIVITY. LEVELS OF CPLA2 MRNA EXPRESSION WERE INCREASED IN PRIMARY CORTICAL NEURONS SUBJECTED TO 0.5-H OXYGEN-GLUCOSE DEPRIVATION INJURY (OGD). THIS INCREASE WAS SIGNIFICANTLY INHIBITED BY C. NUTANS TREATMENT. TREATMENT OF PRIMARY NEURONS WITH THE HDAC INHIBITOR MS-275 AUGMENTED OGD-INDUCED CPLA2 MRNA EXPRESSION, AND THIS INCREASE WAS MODULATED BY C. NUTANS EXTRACTS. OGD-STIMULATED INCREASE IN CPLA2 MRNA EXPRESSION WAS ALSO REDUCED BY A TIP60 HAT INHIBITOR, NU9056. IN VIEW OF A KEY ROLE OF CPLA2 IN THE PRODUCTION OF PRO-INFLAMMATORY EICOSANOIDS AND FREE RADICAL DAMAGE, AND THE FACT THAT EPIGENETIC EFFECTS ON GENES ARE OFTEN LONG-LASTING, RESULTS SUGGEST A ROLE FOR C. NUTANS AND PHYTOCHEMICALS TO INHIBIT THE PRODUCTION OF ARACHIDONIC ACID-DERIVED PRO-INFLAMMATORY EICOSANOIDS AND CHRONIC INFLAMMATION, THROUGH EPIGENETIC REGULATION OF CPLA2 EXPRESSION. 2016 6 4672 28 NEW INSIGHTS INTO THE MECHANISMS OF THE KETOGENIC DIET. PURPOSE OF REVIEW: HIGH-FAT, LOW-CARBOHYDRATE KETOGENIC DIETS HAVE BEEN USED FOR ALMOST A CENTURY FOR THE TREATMENT OF EPILEPSY. USED TRADITIONALLY FOR THE TREATMENT OF REFRACTORY PEDIATRIC EPILEPSIES, IN RECENT YEARS THE USE OF KETOGENIC DIETS HAS EXPERIENCED A REVIVAL TO INCLUDE THE TREATMENT OF ADULTHOOD EPILEPSIES AS WELL AS CONDITIONS RANGING FROM AUTISM TO CHRONIC PAIN AND CANCER. DESPITE THE ABILITY OF KETOGENIC DIET THERAPY TO SUPPRESS SEIZURES REFRACTORY TO ANTIEPILEPTIC DRUGS AND REPORTS OF LASTING SEIZURE FREEDOM, THE UNDERLYING MECHANISMS ARE POORLY UNDERSTOOD. THIS REVIEW EXPLORES NEW INSIGHTS INTO MECHANISMS MOBILIZED BY KETOGENIC DIET THERAPIES. RECENT FINDINGS: KETOGENIC DIETS ACT THROUGH A COMBINATION OF MECHANISMS, WHICH ARE LINKED TO THE EFFECTS OF KETONES AND GLUCOSE RESTRICTION, AND TO INTERACTIONS WITH RECEPTORS, CHANNELS, AND METABOLIC ENZYMES. DECANOIC ACID, A COMPONENT OF MEDIUM-CHAIN TRICLYCERIDES, CONTRIBUTES TO SEIZURE CONTROL THROUGH DIRECT ALPHA-AMINO-3-HYDROXY-5-METHYL-4-ISOXAZOLEPROPIONIC ACID (AMPA) RECEPTOR INHIBITION, WHEREAS DRUGS TARGETING LACTATE DEHYDROGENASE REDUCE SEIZURES THROUGH INHIBITION OF A METABOLIC PATHWAY. KETOGENIC DIET THERAPY ALSO AFFECTS DNA METHYLATION, A NOVEL EPIGENETIC MECHANISM OF THE DIET. SUMMARY: KETOGENIC DIET THERAPY COMBINES SEVERAL BENEFICIAL MECHANISMS THAT PROVIDE BROAD BENEFITS FOR THE TREATMENT OF EPILEPSY WITH THE POTENTIAL TO NOT ONLY SUPPRESS SEIZURES BUT ALSO TO MODIFY THE COURSE OF THE EPILEPSY. 2017 7 1120 37 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 8 3633 44 INCREASE IN HDAC9 SUPPRESSES MYOBLAST DIFFERENTIATION VIA EPIGENETIC REGULATION OF AUTOPHAGY IN HYPOXIA. EXTREMELY REDUCED OXYGEN (O(2)) LEVELS ARE DETRIMENTAL TO MYOGENIC DIFFERENTIATION AND MULTINUCLEATED MYOTUBE FORMATION, AND CHRONIC EXPOSURE TO HIGH-ALTITUDE HYPOXIA HAS BEEN REPORTED TO BE AN IMPORTANT FACTOR IN SKELETAL MUSCLE ATROPHY. HOWEVER, HOW CHRONIC HYPOXIA CAUSES MUSCLE DYSFUNCTION REMAINS UNKNOWN. IN THE PRESENT STUDY, WE FOUND THAT SEVERE HYPOXIA (1% O(2)) SIGNIFICANTLY INHIBITED THE FUNCTION OF C2C12 CELLS (FROM A MYOBLAST CELL LINE). IMPORTANTLY, THE IMPAIRMENT WAS CONTINUOUSLY MANIFESTED EVEN DURING CULTURE UNDER NORMOXIC CONDITIONS FOR SEVERAL PASSAGES. MECHANISTICALLY, WE REVEALED THAT HISTONE DEACETYLASES 9 (HDAC9), A MEMBER OF THE HISTONE DEACETYLASE FAMILY, WAS SIGNIFICANTLY INCREASED IN C2C12 CELLS UNDER HYPOXIC CONDITIONS, THEREBY INHIBITING INTRACELLULAR AUTOPHAGY LEVELS BY DIRECTLY BINDING TO THE PROMOTER REGIONS OF ATG7, BECLIN1, AND LC3. THIS PHENOMENON RESULTED IN THE SEQUENTIAL DEPHOSPHORYLATION OF GSK3BETA AND INACTIVATION OF THE CANONICAL WNT PATHWAY, IMPAIRING THE FUNCTION OF THE C2C12 CELLS. TAKEN TOGETHER, OUR RESULTS SUGGEST THAT HYPOXIA-INDUCED MYOBLAST DYSFUNCTION IS DUE TO ABERRANT EPIGENETIC REGULATION OF AUTOPHAGY, AND OUR EXPERIMENTAL EVIDENCE REVEALS THE POSSIBLE MOLECULAR PATHOGENESIS RESPONSIBLE FOR SOME MUSCLE DISEASES CAUSED BY CHRONIC HYPOXIA AND SUGGESTS A POTENTIAL THERAPEUTIC OPTION. 2019 9 2745 36 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 3721 52 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 11 5947 39 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 12 2482 39 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 13 2353 40 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 14 5865 37 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 15 1105 41 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 16 3191 37 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 17 6232 34 THE LONG NONCODING RNA MEG3 REGULATES MYOBLAST PLASTICITY AND MUSCLE REGENERATION THROUGH EPITHELIAL-MESENCHYMAL TRANSITION. FORMATION OF SKELETAL MUSCLE IS AMONG THE MOST STRIKING EXAMPLES OF CELLULAR PLASTICITY IN ANIMAL TISSUE DEVELOPMENT, AND WHILE MUSCLE PROGENITOR CELLS ARE REPROGRAMMED BY EPITHELIAL-MESENCHYMAL TRANSITION (EMT) TO MIGRATE DURING EMBRYONIC DEVELOPMENT, THE REGULATION OF EMT IN POST-NATAL MYOGENESIS REMAINS POORLY UNDERSTOOD. HERE, WE DEMONSTRATE THAT THE LONG NONCODING RNA (LNCRNA) MEG3 REGULATES EMT IN MYOBLAST DIFFERENTIATION AND SKELETAL MUSCLE REGENERATION. CHRONIC INHIBITION OF MEG3 IN C2C12 MYOBLASTS INDUCED EMT, AND SUPPRESSED CELL STATE TRANSITIONS REQUIRED FOR DIFFERENTIATION. FURTHERMORE, ADENOVIRAL MEG3 KNOCKDOWN COMPROMISED MUSCLE REGENERATION, WHICH WAS ACCOMPANIED BY ABNORMAL MESENCHYMAL GENE EXPRESSION AND INTERSTITIAL CELL PROLIFERATION. TRANSCRIPTOMIC AND PATHWAY ANALYSES OF MEG3-DEPLETED C2C12 MYOBLASTS AND INJURED SKELETAL MUSCLE REVEALED A SIGNIFICANT DYSREGULATION OF EMT-RELATED GENES, AND IDENTIFIED TGFBETA AS A KEY UPSTREAM REGULATOR. IMPORTANTLY, INHIBITION OF TGFBETAR1 AND ITS DOWNSTREAM EFFECTORS, AND THE EMT TRANSCRIPTION FACTOR SNAI2, RESTORED MANY ASPECTS OF MYOGENIC DIFFERENTIATION IN MEG3-DEPLETED MYOBLASTS IN VITRO WE FURTHER DEMONSTRATE THAT REDUCTION OF MEG3-DEPENDENT EZH2 ACTIVITY RESULTS IN EPIGENETIC ALTERATIONS ASSOCIATED WITH TGFBETA ACTIVATION. THUS, MEG3 REGULATES MYOBLAST IDENTITY TO FACILITATE PROGRESSION INTO DIFFERENTIATION. 2021 18 128 34 A UNIFYING MECHANISM OF KETOGENIC DIET ACTION: THE MULTIPLE ROLES OF NICOTINAMIDE ADENINE DINUCLEOTIDE. THE ABILITY OF A KETOGENIC DIET TO TREAT SEIZURES AND RENDER A NEURONAL NETWORK MORE RESISTANT TO STRONG ELECTRICAL ACTIVITY HAS BEEN OBSERVED FOR A CENTURY IN CLINICS AND FOR DECADES IN RESEARCH LABORATORIES. ALONGSIDE ONGOING EFFORTS TO UNDERSTAND HOW THIS THERAPY WORKS TO STOP SEIZURES, METABOLIC HEALTH IS INCREASINGLY APPRECIATED AS CRITICAL BUFFER TO RESISTING AND RECOVERING FROM ACUTE AND CHRONIC DISEASE. ACCORDINGLY, LINKS BETWEEN METABOLISM AND HEALTH, AND THE BROADER EMERGING IMPACT OF THE KETOGENIC DIET IN IMPROVING DIVERSE METABOLIC, IMMUNOLOGICAL AND NEUROLOGICAL CONDITIONS, HAVE SERVED TO INTENSIFY THE SEARCH FOR ITS KEY AND/OR COMMON MECHANISMS. HERE WE REVIEW DIVERSE EVIDENCE FOR INCREASED LEVELS OF NAD(+), AND THUS AN ALTERED RATIO OF NAD(+)/NADH, DURING METABOLIC THERAPY WITH A KETOGENIC DIET. WE PROPOSE THIS AS A POTENTIAL UNIFYING MECHANISM, AND HIGHLIGHT SOME OF THE EVIDENCE LINKING ALTERED NAD(+)/NADH WITH REDUCED SEIZURES AND WITH A RANGE OF SHORT AND LONG-TERM CHANGES ASSOCIATED WITH THE BENEFICIAL EFFECTS OF A KETOGENIC DIET. AN INCREASE IN NAD(+)/NADH IS CONSISTENT WITH MULTIPLE LINES OF EVIDENCE AND HYPOTHESES, AND THEREFORE WE SUGGEST THAT INCREASED NAD(+) MAY BE A COMMON MECHANISM UNDERLYING BENEFICIAL EFFECTS OF KETOGENIC DIET THERAPY. 2020 19 706 45 BUTYRATE AND DIETARY SOLUBLE FIBER IMPROVE NEUROINFLAMMATION ASSOCIATED WITH AGING IN MICE. AGING RESULTS IN CHRONIC SYSTEMIC INFLAMMATION THAT CAN ALTER NEUROINFLAMMATION OF THE BRAIN. SPECIFICALLY, MICROGLIA SHIFT TO A PRO-INFLAMMATORY PHENOTYPE PREDISPOSING THEM TO HYPERACTIVATION UPON STIMULATION BY PERIPHERAL IMMUNE SIGNALS. IT IS PROPOSED THAT CERTAIN NUTRIENTS CAN DELAY BRAIN AGING BY PREVENTING OR REVERSING MICROGLIAL HYPERACTIVATION. BUTYRATE, A SHORT-CHAIN FATTY ACID (SCFA) PRODUCED PRIMARILY BY BACTERIAL FERMENTATION OF FIBER IN THE COLON, HAS BEEN EXTENSIVELY STUDIED PHARMACOLOGICALLY AS A HISTONE DEACETYLASE INHIBITOR AND SERVES AS AN ATTRACTIVE THERAPEUTIC CANDIDATE, AS BUTYRATE HAS ALSO BEEN SHOWN TO BE ANTI-INFLAMMATORY AND IMPROVE MEMORY IN ANIMAL MODELS. IN THIS STUDY, WE DEMONSTRATE THAT BUTYRATE CAN ATTENUATE PRO-INFLAMMATORY CYTOKINE EXPRESSION IN MICROGLIA IN AGED MICE. IT IS STILL NOT FULLY UNDERSTOOD, HOWEVER, IF AN INCREASE IN BUTYRATE-PRODUCING BACTERIA IN THE GUT AS A CONSEQUENCE OF A DIET HIGH IN SOLUBLE FIBER COULD AFFECT MICROGLIAL ACTIVATION DURING AGING. ADULT AND AGED MICE WERE FED EITHER A 1% CELLULOSE (LOW FIBER) OR 5% INULIN (HIGH FIBER) DIET FOR 4 WEEKS. FINDINGS INDICATE THAT MICE FED INULIN HAD AN ALTERED GUT MICROBIOME AND INCREASED BUTYRATE, ACETATE, AND TOTAL SCFA PRODUCTION. IN ADDITION, HISTOLOGICAL SCORING OF THE DISTAL COLON DEMONSTRATED THAT AGED ANIMALS ON THE LOW FIBER DIET HAD INCREASED INFLAMMATORY INFILTRATE THAT WAS SIGNIFICANTLY REDUCED IN ANIMALS CONSUMING THE HIGH FIBER DIET. FURTHERMORE, GENE EXPRESSION OF INFLAMMATORY MARKERS, EPIGENETIC REGULATORS, AND THE MICROGLIAL SENSORY APPARATUS (I.E., THE SENSOME) WERE ALTERED BY BOTH DIET AND AGE, WITH AGED ANIMALS EXHIBITING A MORE ANTI-INFLAMMATORY MICROGLIAL PROFILE ON THE HIGH FIBER DIET. TAKEN TOGETHER, HIGH FIBER SUPPLEMENTATION IN AGING IS A NON-INVASIVE STRATEGY TO INCREASE BUTYRATE LEVELS, AND THESE DATA SUGGEST THAT AN INCREASE IN BUTYRATE THROUGH ADDED SOLUBLE FIBER SUCH AS INULIN COULD COUNTERBALANCE THE AGE-RELATED MICROBIOTA DYSBIOSIS, POTENTIALLY LEADING TO NEUROLOGICAL BENEFITS. 2018 20 5010 41 PEROXIDATION OF LINOLEIC, ARACHIDONIC AND OLEIC ACID IN RELATION TO THE INDUCTION OF OXIDATIVE DNA DAMAGE AND CYTOGENETIC EFFECTS. IN THE PRESENT STUDY, THE POSSIBLE ROLE OF THE POLYUNSATURATED FATTY ACIDS LINOLEIC AND ARACHIDONIC ACID IN THE CHEMICAL INDUCTION OF CARCINOGENESIS HAS BEEN INVESTIGATED. ANALYSIS OF 7,8-DIHYDRO-8-OXO-2'-DEOXYGUANOSINE (8-OXODG) LEVELS IN 2'-DEOXYGUANOSINE (DG) AND ISOLATED DNA HAS DEMONSTRATED THAT LINOLEIC AND ARACHIDONIC ACID ARE CAPABLE OF INDUCING THIS SPECIFIC GENOTOXIC DAMAGE. THIS EFFECT APPEARS TO BE RELATED TO THE DEGREE OF FATTY ACID UNSATURATION, SINCE IT WAS NOT INDUCED BY MONOUNSATURATED OLEIC ACID. ENZYMATIC PEROXIDATION OF LINOLEIC AND ARACHIDONIC ACID RESULTED IN A SIGNIFICANT INCREASE IN OXIDATIVE DNA DAMAGE. STUDIES ON THE INTERFERENCE OF RADICAL SCAVENGERS WITH THE INDUCTION OF 8-OXODG IN COMBINATION WITH ELECTRON SPIN RESONANCE SPECTROSCOPY DEMONSTRATED THAT THE SUPEROXIDE ANION WAS GENERATED DURING PEROXIDATION OF THESE FATTY ACIDS AND THAT SINGLET OXYGEN IS MOST LIKELY INVOLVED IN THE FORMATION OF OXIDATIVE DNA DAMAGE. THE LEVEL OF OXIDATIVE DAMAGE IN DG AND SINGLE-STRANDED DNA WAS HIGHER AS COMPARED TO THAT IN NATIVE DNA AFTER EQUIMOLAR TREATMENT. EXPOSURE OF HUMAN LYMPHOCYTES TO LINOLEIC OR ARACHIDONIC ACID DID NOT RESULT IN A SIGNIFICANT INCREASE IN LEVELS OF 8-OXODG. THIS MAY INDICATE THAT THE RATE OF INTRACELLULAR PEROXIDATION IS RELATIVELY LOW AND/OR THAT NUCLEAR DNA IN INTACT CELLS IS EFFECTIVELY PROTECTED AGAINST GENETIC DAMAGE INDUCED BY REACTIVE OXYGEN SPECIES. IT IS THEREFORE CONCLUDED THAT RELATIVELY SHORT PERIODS OF LINOLEIC OR ARACHIDONIC ACID ADMINISTRATION ARE NOT LIKELY TO IMPOSE A DIRECT GENOTOXIC RISK. IT CAN, HOWEVER, NOT BE EXCLUDED THAT CHRONIC EXPOSURE TO POLYUNSATURATED FATTY ACIDS INDUCES OXIDATIVE DNA DAMAGE OR IS RELATED TO CANCER RISK BY EPIGENETIC MECHANISMS, AS IS ALSO INDICATED BY THE OBSERVED CYTOTOXIC EFFECTS OF LINOLEIC AND ARACHIDONIC ACID. 1994