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Eccentric exercise activates novel transcriptional regulation of hypertrophic signaling pathways

ABSTRACT: Full title: Eccentric exercise activates novel transcriptional regulation of hypertrophic signaling pathways not affected by hormone changes. Unaccustomed eccentric exercise damages muscle tissue stimulating mechanisms of recovery and remodeling that may be affected by cellular protection by the sex hormone 17β-estradiol (E2). Using cDNA microarrays, we screened for differences in mRNA expression caused by E2 and eccentric exercise. After randomly assignment to 8 days of either placebo (CON) or E2 (EXP), eighteen men performed 150 single-leg eccentric contractions. Muscle biopsies were collected at baseline (BL), following supplementation (PS), +3 hours (3H) and +48 hours (48H) after exercise. Serum E2 concentrations increased significantly with supplementation (P < 0.001) but did not affect microarray results. Exercise led to early transcriptional changes in striated muscle activator of Rho signaling (STARS), Rho family GTPase 3 (RND3), mitogen activated protein kinase (MAPK) regulation and the downstream transcription factor FOS. Targeted RT-PCR analysis identified concurrent induction of negative regulators of calcineurin signaling RCAN (P < 0.001) and HMOX1 (P = 0.009). Protein contents were elevated for RND3 at 3H (P = 0.02) and FOS at 48H (P < 0.05). These findings indicate that early RhoA and NFAT signaling and regulation are altered following exercise for muscle remodeling and repair, but are not affected by E2. Eighteen young healthy men volunteered as participants in this study. All subjects were pre-screened to ensure that they were healthy, fit and had not regularly participated in resistance exercise in the preceding 6 months. Body composition was measured using dual energy x-ray absorptiometry (DEXA) scans (Hologic QDR 1000W, Waltham, MA). Thigh muscle cross-sectional area was calculated using anthropomorphic measurements of mid-thigh circumference and skinfold thickness. The subject demographics were (mean ± SD): age, 21 ± 2 y; height, 181 ± 5 cm; weight, 76.9 ± 12.8 kg. Subjects were assigned in a randomized, double-blind manner to either a control (CON, N=9) or experimental (EXP, N=9) group. CON subjects consumed 400 mg glucose polymer (Polycose; Abbott Laboratories, Ross Division, St. Laurent, Quebec, Canada) for 10 days. EXP subjects consumed ~300 mg glucose with 1 mg E2 (Estrace; Shire BioChem, Inc., St. Laurent, Quebec, Canada) for 2 days followed by 2 mg E2 for 8 days. On the morning of the ninth day, subjects reported to the laboratory and performed the exercise protocol. Supplementation continued until the day of the final biopsy and blood collection to maintain serum E2 concentrations throughout the collection protocol. Subjects in both groups were instructed to take one pill at the same time each day and return any unused pills. On the testing day, following a short warm-up (10 min of light cycling), subjects were seated in a Biodex isokinetic dynamometer (System 3, Biodex Medical Systems Inc., Ronkonkoma, NY) with their right leg strapped to a lever arm. The lever arm was programmed to extend their leg to 150º of flexion (where 180º is full extension) at a moderate speed (30º/s), then flex their leg to 90°of flexion at a faster speed (120°/s). During the flexion phase, subjects were instructed to attempt to maximally resist flexion of the knee (i.e. voluntary ‘maximal’ contraction) against the descending lever arm throughout the entire range of motion. The complete test consisted of 15 sets of 10 repetitions, each set separated by 1 minute of rest. Prior to each tissue collection, subjects abstained from any other form of physical exertion (within 72 h), avoided alcohol (within 48 h), ate their habitual diet (within 48 h), and abstained from caffeine (within 12 h). Each subject consumed a 350 Kcal defined formula diet (57% carbohydrates, 15% protein and 28% fat) two hours before each muscle biopsy and did not eat again until after the final biopsy of each session was taken. Muscle biopsies were taken from the vastus lateralis of the control (left) leg during the familiarization session (baseline, BL) and after 8 days of supplementation (post supplementation, PS) and the exercised (right) leg 3 hours (3H) and 48 hours (48H) after exercise, in anatomically distinct sites approximately 6 cm apart. Blood was drawn from the antecubital vein at the same collection times. Muscle and blood samples were processed and stored for future measurements.

ORGANISM(S): Homo sapiens

SUBMITTER: Simon Melov

PROVIDER: E-GEOD-19062 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Eccentric exercise activates novel transcriptional regulation of hypertrophic signaling pathways not affected by hormone changes.

MacNeil Lauren G LG Melov Simon S Hubbard Alan E AE Baker Steven K SK Tarnopolsky Mark A MA

PloS one 20100518 5

Unaccustomed eccentric exercise damages skeletal muscle tissue, activating mechanisms of recovery and remodeling that may be influenced by the female sex hormone 17beta-estradiol (E2). Using high density oligonucleotide based microarrays, we screened for differences in mRNA expression caused by E2 and eccentric exercise. After random assignment to 8 days of either placebo (CON) or E2 (EXP), eighteen men performed 150 single-leg eccentric contractions. Muscle biopsies were collected at baseline ( ...[more]

PMID: 20502695

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Project description:We used gene microarray analysis to compare the global expression profile of genes involved in adaptation to exercise training in skeletal muscle from chronically strength/resistance trained (ST), endurance trained (ET) and untrained control subjects (Con). Resting skeletal muscle samples (~100mg) were obtained from the vastus lateralis of 20 subjects (Con n=7, ET n=7, ST n=6; trained groups >8 years specific training). Total RNA was extracted from tissue and microarrays completed, with test samples compared with standard human reference RNA. Subjects were characterised by performance measures of maximal oxygen uptake (VO2max) on a cycle ergometer and maximal concentric and eccentric leg strength on an isokinetic dynamometer. 263 genes were differentially expressed in trained (TR collectively ET + ST) subjects compared with Con (P<0.05) while 21 genes were different between ST and ET (P<0.05). Manual cluster analyses revealed significant regulation of genes involved in muscle structure and development in TR subjects compared with Con (P<0.05), and expression of these correlated significantly with measures of performance (P<0.05). ET had increased and ST decreased expression of gene clusters related to mitochondrial/oxidative capacity (P<0.05), and these mitochondrial gene clusters correlated significantly with VO2max (P<0.05). VO2max also correlated with expression of gene clusters that regulate fat and carbohydrate oxidation (P<0.05). We have demonstrated that chronic training has marked effects on basal gene expression by regulating levels of multiple mRNAs that transcribe genes for important functional groups in human skeletal muscle. Some specific gene clusters are expressed regardless of the training stimulus, whereas others exhibit divergent expression patterns as a result of specific training stimuli. Keywords: Comparative, cluster analysis, endurance training, strength training, muscle phenotype This was a crossectional study examining basal gene expression profiles of the human vastus lateralis. Twenty healthy males volunteered for this investigation. Seven were endurance trained cyclists (ET), who had been participating in endurance training for 8 yr. These subjects had no history of resistance training. Six subjects were strength trained power-lifters (ST) who had been participating exclusively in strength/resistance training for 9 yr. The final seven subjects were healthy controls (CON) that did not participate in any formal exercise. The study was approved by the Human Research Ethics Committee of RMIT University and Monash University Standing Committee on Ethics Research on Humans. After RNA extraction, amplification and indirect labelling, a dual colour micro-array analysis was conducted by hybridizing a test (muscle RNA; Cy5) sample and a reference (Universal human RNA; Cy3) sample on the AGRF glass slide human 8K micro-array. After data capture with the Genepix scanner and associated software data was normalised and the three populations compared using GeneSpring and simplified cluster analysis.

Project description:The study has been described in the following paper: Gianni Parise, Stuart M. Phillips, Jan J. Kaczor and Mark A. Tarnopolsky (2005). Antioxidant enzyme activity is up-regulated after unilateral resistance exercise training in older adults. Free Radical Biology and Medicine, Volume 39, Issue 2, 15 July 2005, Pages 289-295 We cite the following three paragraphs from this paper: "MATERIALS AND METHODS Subjects Twelve men (71.2 ± 6.5 y) volunteered to participate in a 12 week uni-lateral leg resistance training program (Table 1). All subjects underwent a thorough screening process before being admitted into the study. Subjects were first screened by telephone, and were then subject to a medical evaluation. Consent from their family physician was required, and then all potential subjects underwent a resting electrocardiogram, and a sub-maximal graded exercise test on a bicycle ergometer witih a 12-lead ECG. Exclusion criteria included: evidence of coronary hear disease; congestive heart failure; uncontrolled hypertension; chronic obstructive pulmonary disease; diabetes mellitus; renal failure; major orthopaedic disability; and smoking. None of the subjects had ever participated in a structured exercise program. After subjects were advised of the benefits and risks of participation, subjects gave their written informed consent. The study was approved by the McMaster University and Hamilton Health Sciences Research Ethics Board and conferred to the principles of the declaration of Helsinki. Exercise Training Resistance training was performed three times weekly on non-consecutive days (Monday, Wednesday, and Friday) for 12 weeks, under strict supervision. Prior to and after each training session subjects were required to perform passive stretching. Resistance exercise for each session consisted of 3 sets of 10 repetitions for each of leg press and leg extension. Training progressed from one set of each exercise at 50% of the initial 1 repetition maximum (1RM) to 3 sets at 80% of 1RM over the training period. Training logs were kept to record the volume and intensity of each session. The 1RM was re-evaluated every 2 weeks, and the training load was adjusted accordingly. All exercises were performed on universal strength training equipment (Universal Gym Equipment, Inc., Cedar Rapids, Iowa). Muscle Biopsy A muscle biopsy was taken from the vastus lateralis muscle of both legs before as well as after the training period, 20 cm proximal to the knee joint using a modified Bergström needle (5 mm diameter) with suction modification. The biopsy specimen was dissected of fat and connective tissue and immediately frozen in liquid nitrogen. All samples were stored at -80 °C for subsequent analysis. All subjects were required to abstain from strenuous physical activity for 48 hours prior to the testing session. The non-trained leg performed an acute bout of exercise at the same relative intensity of the training leg to allow for the determination of the effect of training and the effect of acute resistance exercise." Additional Notes: 1) The samples of 8 out 12 were used in the gene expression study. 2) The 2 factors in this study are: 2.1) Leg - Left or Right 2.2) Training - Baseline: samples taken on each leg before exercise - Resistance Training: one of the legs was subject to resistance training followed by acute exercise - Acute Exercise: the other leg had only the acute exercise 3) The baseline samples will be used for right versus left leg comparison to see variance between legs for human experimentation technical issues. The samples from Resistance or Acute Exercise will be compared to corresponding baseline samples to evaluate the effect of both exercise programs on gene expression.

Project description:Massage therapy is commonly used for the physical rehabilitation of skeletal muscle to ameliorate pain and promote recovery from injury. While there is some evidence that massage may relieve pain in injured muscle, the cellular effects remain unknown. To assess the effects of massage, we administered either massage therapy or no treatment to separate quadriceps of eleven young, male participants after exercised-induced muscle damage. Muscle biopsies were acquired from the quadriceps (vastus lateralis) at baseline (rest), immediately after 10 minutes of massage treatment (0h), and after a 2.5 hour period of recovery. We found that massage activated the mechanotransduction signaling pathways FAK and Erk1/2, potentiated mitochondrial biogenesis signaling (nuclear PGC-1α), and mitigated the rise in NFkB (p65) nuclear accumulation caused by muscle trauma. Moreover, in spite of having no effect on muscle metabolites (glycogen, lactate), massage attenuated the production of the inflammatory cytokines TNF-α and IL-6 and reduced HSP27 phosphorylation, effectively mitigating cellular stress resulting from myofiber injury. In summary, massage therapy appears to be clinically beneficial when administered to acutely damaged skeletal muscle by reducing inflammation and promoting mitochondrial biogenesis. 55 muscle biopsies were used in this study as material to evaluate the effects of massage on gene expression. These biopsies were taken from the vastus lateralis of eleven healthy recreationally active males with full ethical approval at McMaster's university. Each individual had an initial biopsy at rest (baseline), followed by exercist testing for peak aerobic capacity. On a second visit, the individual performed a bout of exhaustive aerobic exercise, prior to recieving a randomized massage treatment to one leg. Immediatley following the exercise, subjects were allowed to recover for 10 minutes, while massage oil was lightly applied to both quadriceps. Then a single leg was randomized to recieve massage treatment for 10 minutes. Subjects then rested for 10 minutes, and one additional biopsies were carried out (on each leg). Two and half hours later (3 hours after the cessation of the exercise bout), 2 more biopsies were taken (one from each leg). This amounted to 5 biopsies from each individual.

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Eccentric exercise activates novel transcriptional regulation of hypertrophic signaling pathways

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Eccentric exercise activates novel transcriptional regulation of hypertrophic signaling pathways not affected by hormone changes.

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