title: Targeting β1-integrin signaling enhances regeneration in aged and dystrophic muscle in mice.
abstract: Interactions between stem cells and their microenvironment, or niche, are essential for stem cell maintenance and function. Our knowledge of the niche for the skeletal muscle stem cell, i.e., the satellite cell (SC), is incomplete. Here we show that β1-integrin is an essential niche molecule that maintains SC homeostasis, and sustains the expansion and self-renewal of this stem cell pool during regeneration. We further show that β1-integrin cooperates with fibroblast growth factor 2 (Fgf2), a potent growth factor for SCs, to synergistically activate their common downstream effectors, the mitogen-activated protein (MAP) kinase Erk and protein kinase B (Akt). Notably, SCs in aged mice show altered β1-integrin activity and insensitivity to Fgf2. Augmenting β1-integrin activity with a monoclonal antibody restores Fgf2 sensitivity and improves regeneration after experimentally induced muscle injury. The same treatment also enhances regeneration and function of dystrophic muscles in mdx mice, a model for Duchenne muscular dystrophy. Therefore, β1-integrin senses the SC niche to maintain responsiveness to Fgf2, and this integrin represents a potential therapeutic target for pathological conditions of the muscle in which the stem cell niche is compromised.
authors.affiliation: Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA.|Department of Embryology, Carnegie Institution of Washington, Baltimore, Maryland, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Rozo
authors.affiliation: Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA.|Department of Embryology, Carnegie Institution of Washington, Baltimore, Maryland, USA.
authors.forename: Liangji
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA.|Department of Embryology, Carnegie Institution of Washington, Baltimore, Maryland, USA.
authors.forename: Chen-Ming
authors.initials: CM
authors.lastname: Fan
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D004195:Disease Models, Animal; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D005434:Flow Cytometry; D047468:Immunoprecipitation; D019012:Integrin beta1 / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D018101:Mice, Inbred mdx; D018345:Mice, Knockout; D008856:Microscopy, Fluorescence; D018763:Muscle Fatigue; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000166:cytology / Q000293:injuries / Q000378:metabolism*; D020388:Muscular Dystrophy, Duchenne / Q000378:metabolism; D032446:Myoblasts / Q000166:cytology / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D012038:Regeneration / Q000235:genetics*; D055948:Sarcopenia / Q000378:metabolism; D032496:Satellite Cells, Skeletal Muscle / Q000166:cytology / Q000378:metabolism*
chemical_list: D019012:Integrin beta1; D016222:Fibroblast Growth Factor 2; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases