Mannose receptor regulates myoblast motility and muscle growth.
Myoblast fusion is critical for the formation, growth, and maintenance of skeletal muscle. The initial formation of nascent myotubes requires myoblast-myoblast fusion, but further growth involves myoblast-myotube fusion. We demonstrate that the mannose receptor (MR), a type I transmembrane protein, is required for myoblast-myotube fusion. Mannose receptor (MR)-null myotubes were small in size and contained a decreased myonuclear number both in vitro and in vivo. We hypothesized that this defect may arise from a possible role of MR in cell migration. Time-lapse microscopy revealed that MR-null myoblasts migrated with decreased velocity during myotube growth and were unable to migrate in a directed manner up a chemoattractant gradient. Furthermore, collagen uptake was impaired in MR-null myoblasts, suggesting a role in extracellular matrix remodeling during cell motility. These data identify a novel function for MR during skeletal muscle growth and suggest that myoblast motility may be a key aspect of regulating myotube growth.
Jansen
Katie M
KM
Department of Pharmacology and Program in Biochemistry, Cell, and Developmental Biology, Emory University, Atlanta, GA 30322, USA.
Pavlath
Grace K
GK
D000818:Animals; D002459:Cell Fusion; D002465:Cell Movement; D002467:Cell Nucleus / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D017077:Culture Media, Conditioned; D005260:Female; D005786:Gene Expression Regulation; D037181:Lectins, C-Type / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D024510:Muscle Development / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000166:cytology; D018482:Muscle, Skeletal / Q000166:cytology / Q000473:pathology; D032446:Myoblasts / Q000166:cytology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D012038:Regeneration
D017077:Culture Media, Conditioned; D037181:Lectins, C-Type; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D003094:Collagen