1 2681 94 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 2 3124 31 GHRELIN TREATMENT IMPROVES PHYSICAL DECLINE IN SARCOPENIA MODEL MICE THROUGH MUSCULAR ENHANCEMENT AND MITOCHONDRIAL ACTIVATION. CHRONIC KIDNEY DISEASE (CKD) IMPAIRS PHYSICAL PERFORMANCE IN HUMANS, WHICH LEADS TO A RISK OF ALL-CAUSE MORTALITY. IN OUR PREVIOUS STUDY, WE DEMONSTRATED THAT A REDUCTION IN MUSCLE MITOCHONDRIA RATHER THAN MUSCLE MASS WAS A MAJOR CAUSE OF PHYSICAL DECLINE IN 5/6 NEPHRECTOMIZED CKD MODEL MICE. BECAUSE GHRELIN ADMINISTRATION HAS BEEN REPORTED TO ENHANCE OXYGEN UTILIZATION IN SKELETAL MUSCLE, WE EXAMINED THE USEFULNESS OF GHRELIN FOR A RECOVERY OF PHYSICAL DECLINE IN 5/6 NEPHRECTOMIZED C57BL/6 MICE, FOCUSING ON THE EPIGENETIC MODIFICATION OF PEROXISOME PROLIFERATOR ACTIVATED RECEPTOR GAMMA COACTIVATOR-1ALPHA (PGC-1ALPHA), A MASTER REGULATOR OF MITOCHONDRIAL BIOGENESIS. THE MICE WERE INTRAPERITONEALLY ADMINISTERED ACYLATED GHRELIN (0.1 NMOL/GBW; THREE TIMES PER WEEK) FOR A MONTH. MUSCLE STRENGTH AND EXERCISE ENDURANCE WERE MEASURED BY USING A DYNAMOMETER AND TREADMILL, RESPECTIVELY. MITOCHONDRIAL DNA COPY NUMBER WAS DETERMINED BY QUANTITATIVE PCR. THE METHYLATION LEVELS OF THE CYTOSINE RESIDUE AT 260 BASE PAIRS UPSTREAM OF THE TRANSLATION INITIATION POINT (C-260) OF PGC-1ALPHA, WHICH HAS BEEN DEMONSTRATED TO DECREASE THE EXPRESSION, WAS EVALUATED BY METHYLATION-SPECIFIC PCR AND BISULFITE GENOMIC SEQUENCING METHODS AFTER THE GHRELIN ADMINISTRATION. GHRELIN ADMINISTRATION IMPROVED BOTH MUSCLE STRENGTH AND EXERCISE ENDURANCE IN THE MICE AND WAS ASSOCIATED WITH AN INCREASE IN MUSCLE MASS AND MUSCLE MITOCHONDRIAL CONTENT. GHRELIN ADMINISTRATION DECREASED THE METHYLATION RATIO OF C-260 OF PGC-1ALPHA IN THE SKELETAL MUSCLE AND INCREASED THE EXPRESSION. THEREFORE, GHRELIN ADMINISTRATION EFFECTIVELY REDUCED THE PHYSICAL DECLINE IN 5/6 NEPHRECTOMIZED MICE AND WAS ACCOMPANIED WITH AN INCREASED MITOCHONDRIAL CONTENT THROUGH DE-METHYLATION OF THE PROMOTER REGION OF PGC-1ALPHA IN THE MUSCLE. 2017 3 1632 21 DNMTS ARE INVOLVED IN TGF-BETA1-INDUCED EPITHELIAL-MESENCHYMAL TRANSITIONS IN AIRWAY EPITHELIAL CELLS. CHRONIC RHINOSINUSITIS (CRS) PATHOGENESIS IS CLOSELY RELATED TO TISSUE REMODELING, INCLUDING EPITHELIAL-MESENCHYMAL TRANSITION (EMT). EPIGENETIC MECHANISMS PLAY KEY ROLES IN EMT. DNA METHYLATION, MEDIATED BY DNA METHYLTRANSFERASES (DNMTS), IS AN EPIGENETIC MARKER THAT IS CRITICAL TO EMT. THE GOAL OF THIS STUDY WAS TO DETERMINE WHETHER DNMTS WERE INVOLVED IN TGF-BETA1-INDUCED EMT AND ELUCIDATE THE UNDERLYING MECHANISMS IN NASAL EPITHELIAL CELLS AND AIR-LIQUID INTERFACE CULTURES. GLOBAL DNA METHYLATION AND DNMT ACTIVITY WERE QUANTIFIED. DNMT EXPRESSION WAS MEASURED USING REAL-TIME PCR (QRT-PCR) IN HUMAN CRS TISSUES. MRNA AND PROTEIN LEVELS OF DNMTS, E-CADHERIN, VIMENTIN, ALPHA-SMA, AND FIBRONECTIN WERE DETERMINED USING RT-PCR AND WESTERN BLOTTING, RESPECTIVELY. DNMT1, DNMT3A, AND DNMT3B GENE EXPRESSION WERE KNOCKED DOWN USING SIRNA TRANSFECTION. MAPK PHOSPHORYLATION AND EMT-RELATED TRANSCRIPTION FACTOR LEVELS WERE DETERMINED USING WESTERN BLOTTING. SIGNALING PATHWAYS WERE ANALYZED USING SPECIFIC INHIBITORS OF MAPK. WE DEMONSTRATED THESE DATA IN PRIMARY NASAL EPITHELIAL CELLS AND AIR-LIQUID INTERFACE CULTURES. GLOBAL DNA METHYLATION, DNMT ACTIVITY, AND DNMT EXPRESSION INCREASED IN CRS TISSUES. DNMT EXPRESSION WAS POSITIVELY CORRELATED WITH LUND-MCKAY CT SCORES. TGF-BETA1 DOSE-DEPENDENTLY INDUCED DNMT EXPRESSION. FURTHER, 5-AZA INHIBITED TGF-BETA1-INDUCED DNMT, SNAIL, AND SLUG EXPRESSION RELATED TO EMT, AS WELL AS P38 AND JNK PHOSPHORYLATION IN A549 CELLS AND TGF-BETA1-INDUCED DNMT EXPRESSION AND EMT IN PRIMARY NASAL EPITHELIAL CELLS AND AIR-LIQUID INTERFACE CULTURES. TGF-BETA1-INDUCED DNMT EXPRESSION LEADS TO DNA METHYLATION AND EMT VIA P38, JNK, SNAIL, AND SLUG SIGNALING PATHWAYS. INHIBITION OF DNMT SUPPRESSED THE EMT PROCESS AND THEREFORE IS POTENTIALLY A CRS THERAPEUTIC STRATEGY. 2022 4 5679 26 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 5 4841 36 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 6 920 20 CHRONIC HYPOXIA FACILITATES ALZHEIMER'S DISEASE THROUGH DEMETHYLATION OF GAMMA-SECRETASE BY DOWNREGULATING DNA METHYLTRANSFERASE 3B. INTRODUCTION: ENVIRONMENTAL FACTORS AND EPIGENETIC MECHANISMS ARE BELIEVED TO CONTRIBUTE TO ALZHEIMER'S DISEASE (AD). WE PREVIOUSLY DOCUMENTED THAT PRENATAL HYPOXIA AGGRAVATED THE COGNITIVE IMPAIRMENT AND NEUROPATHOLOGY IN OFFSPRING MICE. HERE, WE INVESTIGATE THE CHRONIC HYPOXIA-INDUCED EPIGENETIC MODIFICATIONS IN AD. METHODS: THE 3-MONTH-OLD APP(SWE)/PS1(DE9) MICE WERE EXPOSED TO HYPOXIC ENVIRONMENT 6 HOUR/DAY FOR 30 DAYS, FOLLOWED BY LEARNING AND MEMORY TESTS AND BIOCHEMICAL AND NEUROPATHOLOGY MEASUREMENT AT THE AGE OF 4, 6, AND 9 MONTHS. RESULTS: WE FOUND HYPOXIA EXAGGERATED THE NEUROPATHOLOGY AND COGNITIVE IMPAIRMENT IN AD MICE. CHRONIC HYPOXIA INDUCED DEMETHYLATION ON GENOMIC DNA AND DECREASED THE EXPRESSION OF DNA METHYLTRANSFERASE 3B (DNMT3B) IN VIVO. WE FURTHER FOUND THAT DNMTS INHIBITION ELEVATED THE PROTEIN LEVELS OF AMYLOID PRECURSOR PROTEIN, BETA- AND GAMMA-SECRETASES, WHEREAS OVEREXPRESSION OF DNMT3B SUPPRESSED THE LEVELS OF THEM IN VITRO. DISCUSSION: OUR STUDY SUGGESTS CHRONIC HYPOXIA CAN AGGRAVATE AD PROGRESSION THROUGH DEMETHYLATION OF GENES ENCODING GAMMA-SECRETASE COMPONENTS BY DOWNREGULATION OF DNMT3B. 2016 7 3589 23 IMPACTS OF ECCENTRIC RESISTANCE EXERCISE ON DNA METHYLATION OF CANDIDATE GENES FOR INFLAMMATORY CYTOKINES IN SKELETAL MUSCLE AND LEUKOCYTES OF HEALTHY MALES. PHYSICAL INACTIVITY AND A POOR DIET INCREASE SYSTEMIC INFLAMMATION, WHILE CHRONIC INFLAMMATION CAN BE REDUCED THROUGH EXERCISE AND NUTRITIONAL INTERVENTIONS. THE MECHANISMS UNDERLYING THE IMPACTS OF LIFESTYLE INTERVENTIONS ON INFLAMMATION REMAIN TO BE FULLY EXPLAINED; HOWEVER, EPIGENETIC MODIFICATIONS MAY BE CRITICAL. THE PURPOSE OF OUR STUDY WAS TO INVESTIGATE THE IMPACTS OF ECCENTRIC RESISTANCE EXERCISE AND FATTY ACID SUPPLEMENTATION ON DNA METHYLATION AND MRNA EXPRESSION OF TNF AND IL6 IN SKELETAL MUSCLE AND LEUKOCYTES. EIGHT NON-RESISTANCE EXERCISE-TRAINED MALES COMPLETED THREE BOUTS OF ISOKINETIC ECCENTRIC CONTRACTIONS OF THE KNEE EXTENSORS. THE FIRST BOUT OCCURRED AT BASELINE, THE SECOND OCCURRED FOLLOWING A THREE-WEEK SUPPLEMENTATION OF EITHER OMEGA-3 POLYUNSATURATED FATTY ACID OR EXTRA VIRGIN OLIVE OIL AND THE FINAL BOUT OCCURRED AFTER EIGHT-WEEKS OF ECCENTRIC RESISTANCE TRAINING AND SUPPLEMENTATION. ACUTE EXERCISE DECREASED SKELETAL MUSCLE TNF DNA METHYLATION BY 5% (P = 0.031), WHEREAS IL6 DNA METHYLATION INCREASED BY 3% (P = 0.01). LEUKOCYTE DNA METHYLATION WAS UNCHANGED FOLLOWING EXERCISE (P > 0.05); HOWEVER, THREE HOURS POST-EXERCISE THE TNF DNA METHYLATION DECREASED BY 2% (P = 0.004). IN SKELETAL MUSCLE, INCREASED TNF AND IL6 MRNA EXPRESSION LEVELS WERE IDENTIFIED IMMEDIATELY POST-EXERCISE (P < 0.027); HOWEVER, THE LEUKOCYTE MRNA EXPRESSION WAS UNCHANGED. ASSOCIATIONS BETWEEN DNA METHYLATION AND MARKERS OF EXERCISE PERFORMANCE, INFLAMMATION AND MUSCLE DAMAGE WERE IDENTIFIED (P < 0.05). ACUTE ECCENTRIC RESISTANCE EXERCISE IS SUFFICIENT TO INDUCE TISSUE-SPECIFIC DNA METHYLATION MODIFICATIONS TO TNF AND IL6; HOWEVER, NEITHER ECCENTRIC TRAINING NOR SUPPLEMENTATION WAS SUFFICIENT TO FURTHER MODIFY THE DNA METHYLATION. 2023 8 169 26 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 9 3604 30 IMPROVEMENT OF PHYSICAL DECLINE THROUGH COMBINED EFFECTS OF MUSCLE ENHANCEMENT AND MITOCHONDRIAL ACTIVATION BY A GASTRIC HORMONE GHRELIN IN MALE 5/6NX CKD MODEL MICE. BECAUSE A PHYSICAL DECLINE CORRELATES WITH AN INCREASED RISK OF A WIDE RANGE OF DISEASE AND MORBIDITY, AN IMPROVEMENT OF PHYSICAL PERFORMANCE IS EXPECTED TO BRING SIGNIFICANT CLINICAL BENEFITS. THE PRIMARY CAUSE OF PHYSICAL DECLINE IN 5/6 NEPHRECTOMIZED (5/6NX) CHRONIC KIDNEY DISEASE MODEL MICE HAS BEEN REGARDED AS A DECREASE IN MUSCLE MASS; HOWEVER, OUR RECENT STUDY SHOWED THAT A DECREASE IN MUSCLE MITOCHONDRIA PLAYS A CRITICAL ROLE. IN THE PRESENT STUDY, WE EXAMINED THE EFFECTS OF A GASTRIC HORMONE GHRELIN, WHICH HAS BEEN REPORTED TO PROMOTE MUSCLE MITOCHONDRIAL OXIDATION, ON THE PHYSICAL DECLINE IN THE CHRONIC KIDNEY DISEASE MODEL MICE, FOCUSING ON THE EPIGENETIC MODULATIONS OF A MITOCHONDRIAL ACTIVATOR GENE, PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR-GAMMA COACTIVATOR-1ALPHA (PGC-1ALPHA). GHRELIN TREATMENT IMPROVED A DECLINE IN EXERCISE ENDURANCE OF 5/6NX MICE, ASSOCIATED WITH AN INCREASE IN BOTH OF THE MUSCLE MASS AND MITOCHONDRIAL AMOUNT. THE EXPRESSION LEVEL OF PGC-1ALPHA WAS DECREASED IN THE SKELETAL MUSCLE OF 5/6NX MICE, WHICH WAS ASSOCIATED WITH AN INCREASE IN THE METHYLATION RATIO OF THE CYTOSINE RESIDUE AT 260 BASE PAIRS UPSTREAM OF THE INITIATION POINT. CONVERSELY, GHRELIN TREATMENT DE-METHYLATED THE CYTOSINE RESIDUE AND INCREASED THE EXPRESSION OF PGC-1ALPHA. A REPRESENTATIVE MUSCLE ANABOLIC FACTOR, IGF-1, DID NOT AFFECT THE EXPRESSION OF PGC-1ALPHA AND MUSCLE MITOCHONDRIAL AMOUNT, ALTHOUGH IT INCREASED MUSCLE MASS. AS A RESULT, IGF-1 TREATMENT IN 5/6NX MICE DID NOT INCREASE THE DECREASED EXERCISE ENDURANCE AS EFFECTIVELY AS GHRELIN TREATMENT DID. THESE FINDINGS INDICATE AN ADVANTAGE OF GHRELIN TREATMENT FOR A RECOVERY OF PHYSICAL DECLINE. 2015 10 5334 25 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 11 1633 28 DO EPIGENETIC EVENTS TAKE PLACE IN THE VASTUS LATERALIS OF PATIENTS WITH MILD CHRONIC OBSTRUCTIVE PULMONARY DISEASE? MUSCLE DYSFUNCTION IS A MAJOR COMORBIDITY IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). SEVERAL BIOLOGICAL MECHANISMS INCLUDING EPIGENETIC EVENTS REGULATE MUSCLE MASS AND FUNCTION IN MODELS OF MUSCLE ATROPHY. INVESTIGATIONS CONDUCTED SO FAR HAVE FOCUSED ON THE ELUCIDATION OF BIOLOGICAL MECHANISMS INVOLVED IN MUSCLE DYSFUNCTION IN ADVANCED COPD. WE ASSESSED WHETHER THE EPIGENETIC PROFILE MAY BE ALTERED IN THE VASTUS LATERALIS OF PATIENTS WITH MILD COPD, NORMAL BODY COMPOSITION, AND MILDLY IMPAIRED MUSCLE FUNCTION AND EXERCISE CAPACITY. IN VASTUS LATERALIS (VL) OF MILD COPD PATIENTS WITH WELL-PRESERVED BODY COMPOSITION AND IN HEALTHY AGE-MATCHED CONTROLS, EXPRESSION OF DNA METHYLATION, MUSCLE-ENRICHED MICRORNAS, HISTONE ACETYLTRANSFERASES (HTAS) AND DEACETYLASES (HDACS), PROTEIN ACETYLATION, SMALL UBIQUITIN-RELATED MODIFIER (SUMO) LIGASES, AND MUSCLE STRUCTURE WERE EXPLORED. ALL SUBJECTS WERE CLINICALLY EVALUATED. COMPARED TO HEALTHY CONTROLS, IN THE VL OF MILD COPD PATIENTS, MUSCLE FUNCTION AND EXERCISE CAPACITY WERE MODERATELY REDUCED, DNA METHYLATION LEVELS DID NOT DIFFER, MIR-1 EXPRESSION LEVELS WERE INCREASED AND POSITIVELY CORRELATED WITH BOTH FORCED EXPIRATORY VOLUME IN ONE SECOND (FEV1) AND QUADRICEPS FORCE, HDAC4 PROTEIN LEVELS WERE INCREASED, AND MUSCLE FIBER TYPES AND SIZES WERE NOT DIFFERENT. MODERATE SKELETAL MUSCLE DYSFUNCTION IS A RELEVANT FEATURE IN PATIENTS WITH MILD COPD AND PRESERVED BODY COMPOSITION. SEVERAL EPIGENETIC EVENTS ARE DIFFERENTIALLY EXPRESSED IN THE LIMB MUSCLES OF THESE PATIENTS, PROBABLY AS AN ATTEMPT TO COUNTERBALANCE THE UNDERLYING MECHANISMS THAT ALTER MUSCLE FUNCTION AND MASS. THE STUDY OF PATIENTS AT EARLY STAGES OF THEIR DISEASE IS OF INTEREST AS THEY ARE A TARGET FOR TIMELY THERAPEUTIC INTERVENTIONS THAT MAY SLOW DOWN THE COURSE OF THE DISEASE AND PREVENT THE DELETERIOUS EFFECTS OF MAJOR COMORBIDITIES. 2014 12 2408 28 EPIGENETIC REWIRING OF SKELETAL MUSCLE ENHANCERS AFTER EXERCISE TRAINING SUPPORTS A ROLE IN WHOLE-BODY FUNCTION AND HUMAN HEALTH. OBJECTIVES: REGULAR PHYSICAL EXERCISE IMPROVES HEALTH BY REDUCING THE RISK OF A PLETHORA OF CHRONIC DISORDERS. WE HYPOTHESIZED THAT ENDURANCE EXERCISE TRAINING REMODELS THE ACTIVITY OF GENE ENHANCERS IN SKELETAL MUSCLE AND THAT THIS REMODELING CONTRIBUTES TO THE BENEFICIAL EFFECTS OF EXERCISE ON HUMAN HEALTH. METHODS AND RESULTS: BY STUDYING CHANGES IN HISTONE MODIFICATIONS, WE MAPPED THE GENOME-WIDE POSITIONS AND ACTIVITIES OF ENHANCERS IN SKELETAL MUSCLE BIOPSIES COLLECTED FROM YOUNG SEDENTARY MEN BEFORE AND AFTER 6 WEEKS OF ENDURANCE EXERCISE. WE IDENTIFIED EXTENSIVE REMODELING OF ENHANCER ACTIVITIES AFTER EXERCISE TRAINING, WITH A LARGE SUBSET OF THE REMODELED ENHANCERS LOCATED IN THE PROXIMITY OF GENES TRANSCRIPTIONALLY REGULATED AFTER EXERCISE. BY OVERLAPPING THE POSITION OF ENHANCERS WITH GENETIC VARIANTS, WE IDENTIFIED AN ENRICHMENT OF DISEASE-ASSOCIATED GENETIC VARIANTS WITHIN THE EXERCISE-REMODELED ENHANCERS. CONCLUSION: OUR DATA PROVIDE EVIDENCE OF A FUNCTIONAL LINK BETWEEN EPIGENETIC REWIRING OF ENHANCERS TO CONTROL THEIR ACTIVITY AFTER EXERCISE TRAINING AND THE MODULATION OF DISEASE RISK IN HUMANS. 2021 13 2709 22 EXERCISE INDUCES AGE-DEPENDENT CHANGES ON EPIGENETIC PARAMETERS IN RAT HIPPOCAMPUS: A PRELIMINARY STUDY. REGULAR EXERCISE IMPROVES LEARNING AND MEMORY, INCLUDING DURING AGING PROCESS. INTERESTINGLY, THE IMBALANCE OF EPIGENETIC MECHANISMS HAS BEEN LINKED TO AGE-RELATED COGNITIVE DEFICITS. HOWEVER, STUDIES ABOUT EPIGENETIC ALTERATIONS AFTER EXERCISE DURING THE AGING PROCESS ARE RARE. IN THIS PRELIMINARY STUDY WE INVESTIGATED THE EFFECT OF AGING AND EXERCISE ON DNA METHYLTRANSFERASES (DNMT1 AND DNMT3B) AND H3-K9 METHYLATION LEVELS IN HIPPOCAMPUS FROM 3 AND 20-MONTHS AGED WISTAR RATS. THE ANIMALS WERE SUBMITTED TO TWO EXERCISE PROTOCOLS: SINGLE SESSION OR CHRONIC TREADMILL PROTOCOL. DNMT1 AND H3-K9 METHYLATION LEVELS WERE DECREASED IN HIPPOCAMPUS FROM AGED RATS. THE SINGLE EXERCISE SESSION DECREASED BOTH DNMT3B AND DNMT1 LEVELS IN YOUNG ADULT RATS, WITHOUT ANY EFFECT IN THE AGED GROUP. BOTH EXERCISE PROTOCOLS REDUCED H3-K9 METHYLATION LEVELS IN YOUNG ADULT RATS, WHILE THE SINGLE SESSION REVERSED THE CHANGES ON H3-K9 METHYLATION LEVELS INDUCED BY AGING. TOGETHER, THESE RESULTS SUGGEST THAT AN IMBALANCE ON DNMTS AND H3-K9 METHYLATION LEVELS MIGHT BE LINKED TO THE BRAIN AGING PROCESS AND THAT THE OUTCOME TO EXERCISE SEEMS TO VARY THROUGH LIFESPAN. 2013 14 2170 27 EPIGENETIC MECHANISMS IN RESPIRATORY MUSCLE DYSFUNCTION OF PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE. EPIGENETIC EVENTS ARE DIFFERENTIALLY EXPRESSED IN THE LUNGS AND AIRWAYS OF PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). MOREOVER, EPIGENETIC MECHANISMS ARE INVOLVED IN THE SKELETAL (PERIPHERAL) MUSCLE DYSFUNCTION OF COPD PATIENTS. WHETHER EPIGENETIC EVENTS MAY ALSO REGULATE RESPIRATORY MUSCLE DYSFUNCTION IN COPD REMAINS UNKNOWN. WE HYPOTHESIZED THAT EPIGENETIC MECHANISMS WOULD BE DIFFERENTIALLY EXPRESSED IN THE MAIN INSPIRATORY MUSCLE (DIAPHRAGM) OF PATIENTS WITH COPD OF A WIDE RANGE OF DISEASE SEVERITY COMPARED TO HEALTHY CONTROLS. IN DIAPHRAGM MUSCLE SPECIMENS (THORACOTOMY DUE TO LUNG LOCALIZED NEOPLASMS) OF SEDENTARY PATIENTS WITH MILD-TO-MODERATE AND SEVERE COPD, WITH PRESERVED BODY COMPOSITION, AND SEDENTARY HEALTHY CONTROLS, EXPRESSION OF MUSCLE-ENRICHED MICRORNAS, HISTONE ACETYLTRANSFERASES (HATS) AND DEACETYLASES (HDACS), TOTAL DNA METHYLATION AND PROTEIN ACETYLATION, SMALL UBIQUITIN-RELATED MODIFIER (SUMO) LIGASES, MUSCLE-SPECIFIC TRANSCRIPTION FACTORS, AND MUSCLE STRUCTURE WERE EXPLORED. ALL SUBJECTS WERE ALSO CLINICALLY EVALUATED: LUNG AND MUSCLE FUNCTIONS AND EXERCISE CAPACITY. COMPARED TO HEALTHY CONTROLS, PATIENTS EXHIBITED MODERATE AIRFLOW LIMITATION AND DIFFUSION CAPACITY, AND REDUCED EXERCISE TOLERANCE AND TRANSDIAPHRAGMATIC STRENGTH. MOREOVER, IN THE DIAPHRAGM OF THE COPD PATIENTS, MUSCLE-SPECIFIC MICRORNA EXPRESSION WAS DOWNREGULATED, WHILE HDAC4 AND MYOCYTE ENHANCER FACTOR (MEF)2C PROTEIN LEVELS WERE HIGHER, AND DNA METHYLATION LEVELS, MUSCLE FIBER TYPES AND SIZES DID NOT DIFFER BETWEEN PATIENTS AND CONTROLS. IN THE MAIN RESPIRATORY MUSCLE OF COPD PATIENTS WITH A WIDE RANGE OF DISEASE SEVERITY AND NORMAL BODY COMPOSITION, MUSCLE-SPECIFIC MICRORNAS WERE DOWNREGULATED, WHILE HDAC4 AND MEF2C LEVELS WERE UPREGULATED. IT IS LIKELY THAT THESE EPIGENETIC EVENTS ACT AS BIOLOGICAL ADAPTIVE MECHANISMS TO BETTER OVERCOME THE CONTINUOUS INSPIRATORY LOADS OF THE RESPIRATORY SYSTEM IN COPD. THESE FINDINGS MAY OFFER NOVEL THERAPEUTIC STRATEGIES TO SPECIFICALLY TARGET RESPIRATORY MUSCLE DYSFUNCTION IN PATIENTS WITH COPD. 2014 15 3836 27 IONIZING RADIATION POTENTIATES HIGH-FAT DIET-INDUCED INSULIN RESISTANCE AND REPROGRAMS SKELETAL MUSCLE AND ADIPOSE PROGENITOR CELLS. EXPOSURE TO IONIZING RADIATION INCREASES THE RISK OF CHRONIC METABOLIC DISORDERS SUCH AS INSULIN RESISTANCE AND TYPE 2 DIABETES LATER IN LIFE. WE HYPOTHESIZED THAT IRRADIATION REPROGRAMS THE EPIGENOME OF METABOLIC PROGENITOR CELLS, WHICH COULD ACCOUNT FOR IMPAIRED METABOLISM AFTER CANCER TREATMENT. C57BL/6 MICE WERE TREATED WITH A SINGLE DOSE OF IRRADIATION AND SUBJECTED TO HIGH-FAT DIET (HFD). RNA SEQUENCING AND REDUCED REPRESENTATION BISULFITE SEQUENCING WERE USED TO CREATE TRANSCRIPTOMIC AND EPIGENOMIC PROFILES OF PREADIPOCYTES AND SKELETAL MUSCLE SATELLITE CELLS COLLECTED FROM IRRADIATED MICE. MICE SUBJECTED TO TOTAL BODY IRRADIATION SHOWED ALTERATIONS IN GLUCOSE METABOLISM AND, WHEN CHALLENGED WITH HFD, MARKED HYPERINSULINEMIA. INSULIN SIGNALING WAS CHRONICALLY DISRUPTED IN SKELETAL MUSCLE AND ADIPOSE PROGENITOR CELLS COLLECTED FROM IRRADIATED MICE AND DIFFERENTIATED IN CULTURE. EPIGENOMIC PROFILING OF SKELETAL MUSCLE AND ADIPOSE PROGENITOR CELLS FROM IRRADIATED ANIMALS REVEALED SUBSTANTIAL DNA METHYLATION CHANGES, NOTABLY FOR GENES REGULATING THE CELL CYCLE, GLUCOSE/LIPID METABOLISM, AND EXPRESSION OF EPIGENETIC MODIFIERS. OUR RESULTS SHOW THAT TOTAL BODY IRRADIATION ALTERS INTRACELLULAR SIGNALING AND EPIGENETIC PATHWAYS REGULATING CELL PROLIFERATION AND DIFFERENTIATION OF SKELETAL MUSCLE AND ADIPOSE PROGENITOR CELLS AND PROVIDE A POSSIBLE MECHANISM BY WHICH IRRADIATION USED IN CANCER TREATMENT INCREASES THE RISK FOR METABOLIC DISEASE LATER IN LIFE. 2016 16 5417 35 REGULATION OF DNA METHYLATION IN RHEUMATOID ARTHRITIS SYNOVIOCYTES. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC INFLAMMATORY DISEASE IN WHICH FIBROBLAST-LIKE SYNOVIOCYTES (FLS) EXHIBIT AN AGGRESSIVE PHENOTYPE. ALTHOUGH THE MECHANISMS RESPONSIBLE ARE NOT WELL DEFINED, EPIGENETIC DETERMINANTS SUCH AS DNA METHYLATION MIGHT CONTRIBUTE. DNA METHYLTRANSFERASES (DNMTS) ARE CRITICAL ENZYMES THAT ESTABLISH AND MAINTAIN DNA METHYLATION. WE EVALUATED WHETHER PROINFLAMMATORY CYTOKINES MIGHT CONTRIBUTE TO DIFFERENTIAL DNA METHYLATION PREVIOUSLY DESCRIBED IN RA FLS THROUGH ALTERED DNMT EXPRESSION. FLS WERE OBTAINED FROM RA AND OSTEOARTHRITIS (OA) SYNOVIUM AT THE TIME OF TOTAL JOINT REPLACEMENT. GENE EXPRESSION WAS DETERMINED BY QUANTITATIVE REAL-TIME PCR AND PROTEIN EXPRESSION BY WESTERN BLOT ANALYSIS. DNMT ACTIVITY WAS MEASURED WITH A FUNCTIONAL ASSAY, AND GLOBAL METHYLATION WAS DETERMINED BY AN IMMUNOASSAY THAT DETECTS METHYLCYTOSINE. RESTING EXPRESSION OF DNMT1, -3A, AND -3B MRNA WERE SIMILAR IN RA AND OA FLS. WESTERN BLOT SHOWED ABUNDANT DNMT1 AND DNMT3A PROTEIN. EXPOSURE TO IL-1 DECREASED DNMT1 AND DNMT3A MRNA EXPRESSION IN FLS. DOSE RESPONSES DEMONSTRATED DECREASED DNMT EXPRESSION AT CONCENTRATIONS AS LOW AS 1 PG/ML OF IL-1. DNMT MRNA LEVELS DECREASED RAPIDLY, WITH SIGNIFICANT SUPPRESSION AFTER 2-8 H OF IL-1 STIMULATION. IL-1 STIMULATION OF OA FLS DID NOT AFFECT METHYLATION OF LINE1 SITES BUT LED TO DEMETHYLATION OF A CHI3L1 LOCUS THAT IS HYPOMETHYLATED IN RA FLS. CHRONIC IL-1 STIMULATION ALSO MIMICKED THE EFFECT OF A DNMT INHIBITOR ON FLS GENE EXPRESSION. EXPOSURE TO PROINFLAMMATORY MEDIATORS REVERSIBLY ALTERS DNA METHYLATION IN FLS BY DECREASING DNMT EXPRESSION AND FUNCTION. THESE DATA SUGGEST THAT IL-1 CAN POTENTIALLY IMPRINT CELLS IN CHRONIC INFLAMMATORY DISEASES. 2013 17 350 32 ALTERED DYNAMICS OF LIPID METABOLISM IN MUSCLE CELLS FROM PATIENTS WITH IDIOPATHIC INFLAMMATORY MYOPATHY IS AMELIORATED BY 6 MONTHS OF TRAINING. KEY POINTS: REGULAR EXERCISE IMPROVES MUSCLE FUNCTIONAL CAPACITY AND CLINICAL STATE OF PATIENTS WITH IDIOPATHIC INFLAMMATORY MYOPATHY (IIM). IN OUR STUDY, WE USED AN IN VITRO MODEL OF HUMAN PRIMARY MUSCLE CELL CULTURES, DERIVED FROM IIM PATIENTS BEFORE AND AFTER A 6-MONTH INTENSIVE SUPERVISED TRAINING INTERVENTION TO ASSESS THE IMPACT OF DISEASE AND EXERCISE ON LIPID METABOLISM DYNAMICS. WE PROVIDE EVIDENCE THAT MUSCLE CELLS FROM IIM PATIENTS DISPLAY ALTERED DYNAMICS OF LIPID METABOLISM AND IMPAIRED ADAPTIVE RESPONSE TO SATURATED FATTY ACID LOAD COMPARED TO HEALTHY CONTROLS. A 6-MONTH INTENSIVE SUPERVISED EXERCISE TRAINING INTERVENTION IN PATIENTS WITH IIM MITIGATED DISEASE EFFECTS IN THEIR CULTURED MUSCLE CELLS, IMPROVING OR NORMALIZING THEIR CAPACITY TO HANDLE LIPIDS. THESE FINDINGS HIGHLIGHT THE PUTATIVE ROLE OF INTRINSIC METABOLIC DEFECTS OF SKELETAL MUSCLE IN THE PATHOGENESIS OF IIM AND THE POSITIVE IMPACT OF EXERCISE, MAINTAINED IN VITRO BY YET UNKNOWN EPIGENETIC MECHANISMS. ABSTRACT: EXERCISE IMPROVES SKELETAL MUSCLE FUNCTION, CLINICAL STATE AND QUALITY OF LIFE IN PATIENTS WITH IDIOPATHIC INFLAMMATORY MYOPATHY (IIM). OUR AIM WAS TO IDENTIFY DISEASE-RELATED METABOLIC PERTURBATIONS AND THE IMPACT OF EXERCISE IN SKELETAL MUSCLE CELLS OF IIM PATIENTS. PATIENTS UNDERWENT A 6-MONTH INTENSIVE SUPERVISED TRAINING INTERVENTION. MUSCLE FUNCTION, ANTHROPOMETRIC AND METABOLIC PARAMETERS WERE EXAMINED AND MUSCLE CELL CULTURES WERE ESTABLISHED (M. VASTUS LATERALIS; BERGSTROM NEEDLE BIOPSY) BEFORE AND AFTER TRAINING FROM PATIENTS AND SEDENTARY AGE/SEX/BODY MASS INDEX-MATCHED CONTROLS. [(14) C]PALMITATE WAS USED TO DETERMINE FAT OXIDATION AND LIPID SYNTHESIS (THIN LAYER CHROMATOGRAPHY). CELLS WERE EXPOSED TO A CHRONIC (3 DAYS) AND ACUTE (3 H) METABOLIC CHALLENGE (THE SATURATED FATTY ACID PALMITATE, 100 MUM). REDUCED OXIDATIVE (INTERMEDIATE METABOLITES, -49%, P = 0.034) AND NON-OXIDATIVE (DIGLYCERIDES, -38%, P = 0.013) LIPID METABOLISM WAS IDENTIFIED IN PALMITATE-TREATED MUSCLE CELLS FROM IIM PATIENTS COMPARED TO CONTROLS. THREE DAYS OF PALMITATE EXPOSURE ELICITED DISTINCT REGULATION OF OXIDATIVE PHOSPHORYLATION (OXPHOS) COMPLEX IV AND COMPLEX V/ATP SYNTHASE (P = 0.012/0.005) AND ADIPOSE TRIGLYCERIDE LIPASE IN PATIENTS COMPARED TO CONTROLS (P = 0.045) (IMMUNOBLOTTING). IMPORTANTLY, 6 MONTHS OF TRAINING IN IIM PATIENTS IMPROVED LIPID METABOLISM (CO(2) , P = 0.010; INTERMEDIATE METABOLITES, P = 0.041) AND ACTIVATION OF AMP KINASE (P = 0.007), AND NEARLY NORMALIZED PALMITATE-INDUCED CHANGES IN OXPHOS PROTEINS IN MYOTUBES FROM IIM PATIENTS, IN PARALLEL WITH IMPROVEMENTS OF PATIENTS' CLINICAL STATE. MYOTUBES FROM IIM PATIENTS DISPLAYED ALTERED DYNAMICS OF LIPID METABOLISM AND IMPAIRED RESPONSE TO METABOLIC CHALLENGE WITH SATURATED FATTY ACID. OUR OBSERVATIONS SUGGEST THAT METABOLIC DEFECTS INTRINSIC TO SKELETAL MUSCLE COULD REPRESENT NON-IMMUNE PATHOMECHANISMS, WHICH CAN CONTRIBUTE TO MUSCLE WEAKNESS IN IIM. A 6-MONTH TRAINING INTERVENTION MITIGATED DISEASE EFFECTS IN MUSCLE CELLS IN VITRO, INDICATING THE EXISTENCE OF EPIGENETIC REGULATORY MECHANISMS. 2021 18 897 30 CHRONIC EXERCISE TRAINING ACTIVATES HISTONE TURNOVER IN MOUSE SKELETAL MUSCLE FIBERS. EPIGENETIC REGULATION OF SKELETAL MUSCLE ADAPTATION TO EXERCISE IS A RECENT TOPIC FOR WHICH THERE IS LIMITED INFORMATION. THIS STUDY INVESTIGATED WHETHER EXERCISE TRAINING ACTIVATES HISTONE TURNOVER IN THE SKELETAL MUSCLE FIBERS OF MICE. EXPERIMENTS USING A TETRACYCLINE-INDUCIBLE H2B-GFP EXPRESSION MODEL DEMONSTRATED THAT 4 WEEKS OF RUNNING TRAINING, BUT NOT 2 WEEKS OF TRAINING, SIGNIFICANTLY PROMOTED THE INCORPORATION OF H2B-GFP INTO NUCLEOSOMES AND THE DISSOCIATION OF HISTONE H3.3 AT BOTH TRANSCRIPTIONALLY UPREGULATED AND NONRESPONSIVE LOCI. MUSCLE-SPECIFIC PGC-1ALPHA-B-OVEREXPRESSING MICE CROSSED WITH H2B-GFP MICE SHOWED A SLIGHT INCREASE IN H2B-GFP INCORPORATION AT TRANSCRIPTIONALLY ACTIVE LOCI, BUT NOT IN THE DISSOCIATION OF H3.3 FROM NUCLEOSOMES. GENE EXPRESSION RESPONSES TO A SINGLE BOUT OF RUNNING WERE SIGNIFICANTLY ENHANCED IN 4-WEEK TRAINED MICE WHEN COMPARED WITH THOSE IN 2-WEEK TRAINED MICE. THE MOST DRASTIC INCREASE IN THE GENE RESPONSE WAS FOUND IN THE EXPRESSION OF HSPA1A AND HSPA1B, IN WHICH THE MAGNITUDE OF UPREGULATION IN RESPONSE TO RUNNING WAS SIGNIFICANTLY ENHANCED FROM 8-FOLD IN 2 WEEK TRAINED MICE TO 97- AND 121-FOLD IN 4 WEEK TRAINED MICE, RESPECTIVELY. IT WAS ALSO FOUND THAT THE HSP70 LEVEL INCREASED DURING THE TRAINING PERIOD. IN A MYONUCLEAR IMMUNOHISTOCHEMICAL ANALYSIS OF CHROMATIN REMODELERS, WE FURTHER FOUND THAT THE LEVEL OF SPT16, AN H2A-H2B-SPECIFIC CHAPERONE, WAS UPREGULATED AFTER RUNNING TRAINING. THESE RESULTS REVEALED THAT 4 WEEKS OF RUNNING TRAINING ACTIVATED HISTONE TURNOVER IN SKELETAL MUSCLE FIBERS. THEY ALSO SUGGESTED THAT HISTONE TURNOVER LED TO LOOSENING OF THE NUCLEOSOMES AND ENHANCED GENE RESPONSES TO EXERCISE. 2021 19 5856 21 SUBSTRATE UTILISATION OF CULTURED SKELETAL MUSCLE CELLS IN PATIENTS WITH CFS. CHRONIC FATIGUE SYNDROME (CFS) PATIENTS OFTEN SUFFER FROM SEVERE MUSCLE PAIN AND AN INABILITY TO EXERCISE DUE TO MUSCLE FATIGUE. IT HAS PREVIOUSLY BEEN SHOWN THAT CFS SKELETAL MUSCLE CELLS HAVE LOWER LEVELS OF ATP AND HAVE AMP-ACTIVATED PROTEIN KINASE DYSFUNCTION. THIS STUDY OUTLINES EXPERIMENTS LOOKING AT THE UTILISATION OF DIFFERENT SUBSTRATES BY SKELETAL MUSCLE CELLS FROM CFS PATIENTS (N = 9) AND HEALTHY CONTROLS (N = 11) USING EXTRACELLULAR FLUX ANALYSIS. RESULTS SHOW THAT CFS SKELETAL MUSCLE CELLS ARE UNABLE TO UTILISE GLUCOSE TO THE SAME EXTENT AS HEALTHY CONTROL CELLS. CFS SKELETAL MUSCLE CELLS WERE SHOWN TO OXIDISE GALACTOSE AND FATTY ACIDS NORMALLY, INDICATING THAT THE BIOENERGETIC DYSFUNCTION LIES UPSTREAM OF THE TCA CYCLE. THE DYSFUNCTION IN GLUCOSE OXIDATION IS SIMILAR TO WHAT HAS PREVIOUSLY BEEN SHOWN IN BLOOD CELLS FROM CFS PATIENTS. THE CONSISTENCY OF CELLULAR BIOENERGETIC DYSFUNCTION IN DIFFERENT CELL TYPES SUPPORTS THE HYPOTHESIS THAT CFS IS A SYSTEMIC DISEASE. THE RETENTION OF BIOENERGETIC DEFECTS IN CULTURED CELLS INDICATES THAT THERE IS A GENETIC OR EPIGENETIC COMPONENT TO THE DISEASE. THIS IS THE FIRST STUDY TO USE CELLS DERIVED FROM SKELETAL MUSCLE BIOPSIES IN CFS PATIENTS AND HEALTHY CONTROLS TO LOOK AT CELLULAR BIOENERGETIC FUNCTION IN WHOLE CELLS. 2020 20 6232 21 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