This application for a Mentored Research Scientist Development Award (K01) describes a training program and research project that provides the candidate with the necessary skills and laboratory-based techniques to conduct clinical research studies and to make the transition to an independent researcher. Candidate: The candidate's long term goal is to develop his own research program focusing on the structural and functional alterations in human skeletal muscle that result from aging, disuse and disease. The candidate is a Research Associate at the University of Vermont with a background in engineering. He has, for the first time, applied the novel technique of sinusoidal analysis to single human skeletal muscle fibers;thereby allowing the first examinations of the molecular determinants of contractile function in humans. Environment: The University of Vermont is ideally suited to the candidate's proposed research and training. It includes a cohesive group of clinicians and basic science researchers engaged in clinical research and muscle physiology that examines function at the whole body, whole muscle, single fiber and single molecule levels. Research: The objective of the proposed research study is to characterize the molecular mechanisms underlying age-related changes in single human skeletal muscle fiber function. We hypothesize that aging impairs single fiber function by: 1) altering myosin kinetics (increasing myosin attachment time and decreasing myosin rate of force production) and 2) decreasing myosin heavy chain content. To test these hypotheses, contractile performance and myofibrillar protein expression from single skeletal muscle fibers will be obtained from young (21-35 yrs old) and elderly (65-75 yrs old) volunteers. The proposed studies will represent the first comprehensive examination of the mechanisms underlying human skeletal muscle contractile dysfunction with aging at the molecular level. Relevance: Understanding age-related skeletal muscle contractile dysfunction at the level of the myosin- actin cross-bridge is a necessary step towards developing more effective pharmacological and lifestyle countermeasures to correct sarcopenia that are directed specifically at molecular defects.

National Institute of Health (NIH)
National Institute on Aging (NIA)
Research Scientist Development Award - Research & Training (K01)
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Study Section
National Institute on Aging Initial Review Group (NIA)
Program Officer
Dutta, Chhanda
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University of Vermont & St Agric College
Schools of Medicine
United States
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Tanner, Bertrand C W; McNabb, Mark; Palmer, Bradley M et al. (2014) Random myosin loss along thick-filaments increases myosin attachment time and the proportion of bound myosin heads to mitigate force decline in skeletal muscle. Arch Biochem Biophys 552-553:117-27
Callahan, Damien M; Bedrin, Nicholas G; Subramanian, Meenakumari et al. (2014) Age-related structural alterations in human skeletal muscle fibers and mitochondria are sex specific: relationship to single-fiber function. J Appl Physiol (1985) 116:1582-92
Toth, Michael J; Miller, Mark S; Callahan, Damien M et al. (2013) Molecular mechanisms underlying skeletal muscle weakness in human cancer: reduced myosin-actin cross-bridge formation and kinetics. J Appl Physiol (1985) 114:858-68
Palmer, Bradley M; Tanner, Bertrand C W; Toth, Michael J et al. (2013) An inverse power-law distribution of molecular bond lifetimes predicts fractional derivative viscoelasticity in biological tissue. Biophys J 104:2540-52
Miller, Mark S; Bedrin, Nicholas G; Callahan, Damien M et al. (2013) Age-related slowing of myosin actin cross-bridge kinetics is sex specific and predicts decrements in whole skeletal muscle performance in humans. J Appl Physiol (1985) 115:1004-14
Toth, Michael J; Miller, Mark S; VanBuren, Peter et al. (2012) Resistance training alters skeletal muscle structure and function in human heart failure: effects at the tissue, cellular and molecular levels. J Physiol 590:1243-59
Tanner, Bertrand C W; Miller, Mark S; Miller, Becky M et al. (2011) COOH-terminal truncation of flightin decreases myofilament lattice organization, cross-bridge binding, and power output in Drosophila indirect flight muscle. Am J Physiol Cell Physiol 301:C383-91
Palmer, Bradley M; Wang, Yuan; Miller, Mark S (2011) Distribution of myosin attachment times predicted from viscoelastic mechanics of striated muscle. J Biomed Biotechnol 2011:592343
Miller, Mark S; VanBuren, Peter; LeWinter, Martin M et al. (2010) Chronic heart failure decreases cross-bridge kinetics in single skeletal muscle fibres from humans. J Physiol 588:4039-53
Miller, Mark S; Tanner, Bertrand C W; Nyland, Lori R et al. (2010) Comparative biomechanics of thick filaments and thin filaments with functional consequences for muscle contraction. J Biomed Biotechnol 2010:473423

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