Skeletal muscle undergoes rapid growth during the earlier phase of postnatal life and declines in mass and strength upon aging. Satellite cells are the myogenic precursors in the postnatal muscle, participating in myofiber growth and repair. Gaining insight into how the dynamics of myofiber growth is regulated is a critical step toward the future development of therapies aimed at reducing age-related muscle atrophy. The proposed investigation will examine the involvement of the fibroblast growth factor (FGF) system during satellite cell differentiation and muscle growth. The overall hypothesis of the proposal is that FGF receptor 4 (FGFR4) mediates specific aspects of FGF signaling during satellite cell differentiation and myofiber growth in the postnatal environment.
The specific aims of the proposal are: 1. To investigate the role of FGFR4 during differentiation of adult myoblasts. 2. The investigate the role of FGFR4 in myofiber growth. 3. To analyze the dynamics of muscle regeneration in mice lacking FGFR4. A comprehensive approach of cell culture and in vivo studies will be undertaken. For functional studies, a retroviral-based expression vector will be developed in which FGFR4 dimerization/activation is induced by a synthetic drug. The expression of this inducible FGFR4 in myoblasts from mice lacking FGFR4 will provide a tightly regulated system for investigating the role of the FGF system during differentiation of myoblasts and formation of myotubes. The in vivo studies will utilize a synchronized system of muscle injury and regeneration to investigate the role of FGFR4 in a physiological relevant model of myogenesis. Assays to be used in the studies include immunocytochemistry, Western blotting, RT-PCR and proteomics. The proposed investigation will contribute to a better understanding of satellite cell dynamics and muscle growth, and can prove important for muscle rehabilitation strategies during disease and aging.

National Institute of Health (NIH)
National Institute on Aging (NIA)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1-SMB (01))
Program Officer
Williams, John
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Washington
Anatomy/Cell Biology
Schools of Medicine
United States
Zip Code
Keire, Paul; Shearer, Andrew; Shefer, Gabi et al. (2013) Isolation and culture of skeletal muscle myofibers as a means to analyze satellite cells. Methods Mol Biol 946:431-68
Danoviz, Maria Elena; Yablonka-Reuveni, Zipora (2012) Skeletal muscle satellite cells: background and methods for isolation and analysis in a primary culture system. Methods Mol Biol 798:21-52
Day, Kenneth; Shefer, Gabi; Shearer, Andrew et al. (2010) The depletion of skeletal muscle satellite cells with age is concomitant with reduced capacity of single progenitors to produce reserve progeny. Dev Biol 340:330-43
Kirkpatrick, Lisa J; Yablonka-Reuveni, Zipora; Rosser, Benjamin W C (2010) Retention of Pax3 expression in satellite cells of muscle spindles. J Histochem Cytochem 58:317-27
Ieronimakis, Nicholas; Balasundaram, Gayathri; Rainey, Sabrina et al. (2010) Absence of CD34 on murine skeletal muscle satellite cells marks a reversible state of activation during acute injury. PLoS One 5:e10920
Day, Kenneth; Paterson, Bruce; Yablonka-Reuveni, Zipora (2009) A distinct profile of myogenic regulatory factor detection within Pax7+ cells at S phase supports a unique role of Myf5 during posthatch chicken myogenesis. Dev Dyn 238:1001-9
Kirkpatrick, Lisa J; Allouh, Mohammed Z; Nightingale, Chantale N et al. (2008) Pax7 shows higher satellite cell frequencies and concentrations within intrafusal fibers of muscle spindles. J Histochem Cytochem 56:831-40
Yablonka-Reuveni, Z; Day, K; Vine, A et al. (2008) Defining the transcriptional signature of skeletal muscle stem cells. J Anim Sci 86:E207-16
Kwiatkowski, Boguslaw A; Kirillova, Irina; Richard, Robert E et al. (2008) FGFR4 and its novel splice form in myogenic cells: Interplay of glycosylation and tyrosine phosphorylation. J Cell Physiol 215:803-17
Allouh, Mohammed Z; Yablonka-Reuveni, Zipora; Rosser, Benjamin W C (2008) Pax7 reveals a greater frequency and concentration of satellite cells at the ends of growing skeletal muscle fibers. J Histochem Cytochem 56:77-87

Showing the most recent 10 out of 31 publications