Rehabilitation and Therapy Commons^™

A Muscle Cell-Macrophage Axis Involving Matrix Metalloproteinase 14 Facilitates Extracellular Matrix Remodeling With Mechanical Loading, Bailey D. Peck, Kevin A. Murach, R. Grace Walton, Alexander J. Simmons, Douglas E. Long, Kate Kosmac, Cory M. Dungan, Philip A. Kern, Marcas M. Bamman, Charlotte A. Peterson

Center for Muscle Biology Faculty Publications

The extracellular matrix (ECM) in skeletal muscle plays an integral role in tissue development, structural support, and force transmission. For successful adaptation to mechanical loading, remodeling processes must occur. In a large cohort of older adults, transcriptomics revealed that genes involved in ECM remodeling, including matrix metalloproteinase 14 (MMP14), were the most upregulated following 14 weeks of progressive resistance exercise training (PRT). Using single-cell RNA-seq, we identified macrophages as a source of Mmp14 in muscle following a hypertrophic exercise stimulus in mice. In vitro contractile activity in myotubes revealed that the gene encoding cytokine leukemia inhibitory factor ( …

Differential Requirement For Satellite Cells During Overload-Induced Muscle Hypertrophy In Growing Versus Mature Mice, Kevin A. Murach, Sarah H. White, Yuan Wen, Angel Ho, Esther E. Dupont-Versteegden, John J. Mccarthy, Charlotte A. Peterson

Physical Therapy Faculty Publications

Background: Pax7+ satellite cells are required for skeletal muscle fiber growth during post-natal development in mice. Satellite cell-mediated myonuclear accretion also appears to persist into early adulthood. Given the important role of satellite cells during muscle development, we hypothesized that the necessity of satellite cells for adaptation to an imposed hypertrophic stimulus depends on maturational age.

Methods: Pax7^CreER-R26R^DTA mice were treated for 5 days with vehicle (satellite cell-replete, SC+) or tamoxifen (satellite cell-depleted, SC-) at 2 months (young) and 4 months (mature) of age. Following a 2-week washout, mice were subjected to sham surgery or 10 day …