Browsing by Author "Ruple, Bradley A"

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    Acute and chronic effects of resistance training on skeletal muscle markers of mitochondrial remodeling in older adults
    (Physiological Reports, 2020-08) Mesquita, Paulo HC; Lamb, Donald A; Parry, Hailey A; Moore, Johnathon H; Smith, Morgan A; Vann, Christopher G; Osburn, Shelby C; Fox, Carlton D; Ruple, Bradley A; Huggins, Kevin W; Fruge, Andrew D; Young, Kaelin C; Kavazis, Andreas N; Roberts, Michael D
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    Different Resistance Exercise Loading Paradigms Similarly Affect Skeletal Muscle Gene Expression Patterns of Myostatin-Related Targets and mTORC1 Signaling Markers.
    (Cells, 2023-03) McIntosh, Mason C; Sexton, Casey L; Godwin, Joshua S; Ruple, Bradley A; Michel, J Max; Plotkin, Daniel L; Ziegenfuss, Tim N; Lopez, Hector L; Smith, Ryan; Dwaraka, Varun B; Sharples, Adam P; Dalbo, Vincent J; Mobley, C Brooks; Vann, Christopher G; Roberts, Michael D
    Although transcriptome profiling has been used in several resistance training studies, the associated analytical approaches seldom provide in-depth information on individual genes linked to skeletal muscle hypertrophy. Therefore, a secondary analysis was performed herein on a muscle transcriptomic dataset we previously published involving trained college-aged men (n = 11) performing two resistance exercise bouts in a randomized and crossover fashion. The lower-load bout (30 Fail) consisted of 8 sets of lower body exercises to volitional fatigue using 30% one-repetition maximum (1 RM) loads, whereas the higher-load bout (80 Fail) consisted of the same exercises using 80% 1 RM loads. Vastus lateralis muscle biopsies were collected prior to (PRE), 3 h, and 6 h after each exercise bout, and 58 genes associated with skeletal muscle hypertrophy were manually interrogated from our prior microarray data. Select targets were further interrogated for associated protein expression and phosphorylation induced-signaling events. Although none of the 58 gene targets demonstrated significant bout x time interactions, ~57% (32 genes) showed a significant main effect of time from PRE to 3 h (15↑ and 17↓, p < 0.01), and ~26% (17 genes) showed a significant main effect of time from PRE to 6 h (8↑ and 9↓, p < 0.01). Notably, genes associated with the myostatin (9 genes) and mammalian target of rapamycin complex 1 (mTORC1) (9 genes) signaling pathways were most represented. Compared to mTORC1 signaling mRNAs, more MSTN signaling-related mRNAs (7 of 9) were altered post-exercise, regardless of the bout, and RHEB was the only mTORC1-associated mRNA that was upregulated following exercise. Phosphorylated (phospho-) p70S6K (Thr389) (p = 0.001; PRE to 3 h) and follistatin protein levels (p = 0.021; PRE to 6 h) increased post-exercise, regardless of the bout, whereas phospho-AKT (Thr389), phospho-mTOR (Ser2448), and myostatin protein levels remained unaltered. These data continue to suggest that performing resistance exercise to volitional fatigue, regardless of load selection, elicits similar transient mRNA and signaling responses in skeletal muscle. Moreover, these data provide further evidence that the transcriptional regulation of myostatin signaling is an involved mechanism in response to resistance exercise.
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    Effects of High-Volume Versus High-Load Resistance Training on Skeletal Muscle Growth and Molecular Adaptations.
    (Frontiers in physiology, 2022-01) Vann, Christopher G; Sexton, Casey L; Osburn, Shelby C; Smith, Morgan A; Haun, Cody T; Rumbley, Melissa N; Mumford, Petey W; Montgomery, Nathan T; Ruple, Bradley A; McKendry, James; Mcleod, Jonathan; Bashir, Adil; Beyers, Ronald J; Brook, Matthew S; Smith, Kenneth; Atherton, Philip J; Beck, Darren T; McDonald, James R; Young, Kaelin C; Phillips, Stuart M; Roberts, Michael D
    We evaluated the effects of higher-load (HL) versus (lower-load) higher-volume (HV) resistance training on skeletal muscle hypertrophy, strength, and muscle-level molecular adaptations. Trained men (n = 15, age: 23 ± 3 years; training experience: 7 ± 3 years) performed unilateral lower-body training for 6 weeks (3× weekly), where single legs were randomly assigned to HV and HL paradigms. Vastus lateralis (VL) biopsies were obtained prior to study initiation (PRE) as well as 3 days (POST) and 10 days following the last training bout (POSTPR). Body composition and strength tests were performed at each testing session, and biochemical assays were performed on muscle tissue after study completion. Two-way within-subject repeated measures ANOVAs were performed on most dependent variables, and tracer data were compared using dependent samples t-tests. A significant interaction existed for VL muscle cross-sectional area (assessed via magnetic resonance imaging; interaction p = 0.046), where HV increased this metric from PRE to POST (+3.2%, p = 0.018) whereas HL training did not (-0.1%, p = 0.475). Additionally, HL increased leg extensor strength more so than HV training (interaction p = 0.032; HV < HL at POST and POSTPR, p < 0.025 for each). Six-week integrated non-myofibrillar protein synthesis (iNon-MyoPS) rates were also higher in the HV versus HL condition, while no difference between conditions existed for iMyoPS rates. No interactions existed for other strength, VL morphology variables, or the relative abundances of major muscle proteins. Compared to HL training, 6 weeks of HV training in previously trained men optimizes VL hypertrophy in lieu of enhanced iNon-MyoPS rates, and this warrants future research.
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    Effects of Resistance Training on the Redox Status of Skeletal Muscle in Older Adults
    (Antioxidants) Mesquita, Paulo HC; Lamb, Donald A; Godwin, Joshua S; Osburn, Shelby C; Ruple, Bradley A; Moore, Johnathon H; Vann, Christopher G; Huggins, Kevin W; Fruge, Andrew D; Young, Kaelin C; Kavazis, Andreas N; Roberts, Michael D
    The aim of this study was to investigate the effects of resistance training (RT) on the redox status of skeletal muscle in older adults. Thirteen males aged 64 ± 9 years performed full-body RT 2x/week for 6 weeks. Muscle biopsies were obtained from the vastus lateralis prior to and following RT. The mRNA, protein, and enzymatic activity levels of various endogenous antioxidants were determined. In addition, skeletal muscle 4-hydroxynonenal and protein carbonyls were determined as markers of oxidative damage. Protein levels of heat shock proteins (HSPs) were also quantified. RT increased mRNA levels of all assayed antioxidant genes, albeit protein levels either did not change or decreased. RT increased total antioxidant capacity, catalase, and glutathione reductase activities, and decreased glutathione peroxidase activity. Lipid peroxidation also decreased and HSP60 protein increased following RT. In summary, 6 weeks of RT decreased oxidative damage and increased antioxidant enzyme activities. Our results suggest the older adult responses to RT involve multi-level (transcriptional, post-transcriptional, and post-translational) control of the redox status of skeletal muscle.
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    Resistance training rejuvenates the mitochondrial methylome in aged human skeletal muscle
    (The FASEB Journal, 2021-09) Ruple, Bradley A; Godwin, Joshua S; Mesquita, Paulo HC; Osburn, Shelby C; Vann, Christopher G; Lamb, Donald A; Sexton, Casey L; Candow, Darren G; Forbes, Scott C; Frugé, Andrew D; Kavazis, Andreas N; Young, Kaelin C; Seaborne, Robert A; Sharples, Adam P; Roberts, Michael D
    AbstractResistance training (RT) dynamically alters the skeletal muscle nuclear DNA methylome. However, no study has examined if RT affects the mitochondrial DNA (mtDNA) methylome. Herein, ten older, Caucasian untrained males (65 ± 7 y.o.) performed six weeks of full‐body RT (twice weekly). Body composition and knee extensor torque were assessed prior to and 72 h following the last RT session. Vastus lateralis (VL) biopsies were also obtained. VL DNA was subjected to reduced representation bisulfite sequencing providing excellent coverage across the ~16‐kilobase mtDNA methylome (254 CpG sites). Biochemical assays were also performed, and older male data were compared to younger trained males (22 ± 2 y.o., n = 7, n = 6 Caucasian & n = 1 African American). RT increased whole‐body lean tissue mass (p = .017), VL thickness (p = .012), and knee extensor torque (p = .029) in older males. RT also affected the mtDNA methylome, as 63% (159/254) of the CpG sites demonstrated reduced methylation (p < .05). Several mtDNA sites presented a more “youthful” signature in older males after RT in comparison to younger males. The 1.12 kilobase mtDNA D‐loop/control region, which regulates replication and transcription, possessed enriched hypomethylation in older males following RT. Enhanced expression of mitochondrial H‐ and L‐strand genes and complex III/IV protein levels were also observed (p < .05). While limited to a shorter‐term intervention, this is the first evidence showing that RT alters the mtDNA methylome in skeletal muscle. Observed methylome alterations may enhance mitochondrial transcription, and RT evokes mitochondrial methylome profiles to mimic younger men. The significance of these findings relative to broader RT‐induced epigenetic changes needs to be elucidated.
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    The effects of resistance training with or without peanut protein supplementation on skeletal muscle and strength adaptations in older individuals
    (Journal of the International Society of Sports Nutrition, 2020-01-03) Lamb, Donald A; Moore, Johnathon H; Smith, Morgan A; Vann, Christopher G; Osburn, Shelby C; Ruple, Bradley A; Fox, Carlton D; Smith, Kristen S; Altonji, Olivia M; Power, Zade M; Cerovsky, Annsley E; Ross, C Owen; Cao, Andy T; Goodlett, Michael D; Huggins, Kevin W; Fruge, Andrew D; Young, Kaelin C; Roberts, Michael D