Tissue inhibitor of metalloproteinase-2 (TIMP-2) regulates myogenesis and beta1 integrin expression in vitro.
Myogenesis in vitro involves myoblast cell cycle arrest, migration, and fusion to form multinucleated myotubes. Extracellular matrix (ECM) integrity during these processes is maintained by the opposing actions of matrix metalloproteinase (MMP) proteases and their inhibitors, the tissue inhibitor of metalloproteinases (TIMPs). Here, we report that TIMP-2, MMP-2, and MT1-MMP are differentially expressed during mouse myoblast differentiation in vitro. A specific role for TIMP-2 in myogenesis is demonstrated by altered TIMP-2(-/-) myotube formation. When differentiated in horse serum-containing medium, TIMP-2(-/-) myotubes are larger than wild-type myotubes. In contrast, when serum-free medium is used, TIMP-2(-/-) myotubes are smaller than wild-type myotubes. Regardless of culture condition, myotube size is directly correlated with MMP activity and inversely correlated with beta1 integrin expression. Treatment with recombinant TIMP-2 rescues reduced TIMP-2(-/-) myotube size and induces increased MMP-9 activation and decreased beta1 integrin expression. Treatment with either MMP-2 or MMP-9 similarly rescues reduced myotube size, but has no effect on beta1 integrin expression. These data suggest a specific regulatory relationship between TIMP-2 and beta1 integrin during myogenesis. Elucidating the role of TIMP-2 in myogenesis in vitro may lead to new therapeutic options for the use of TIMP-2 in myopathies and muscular dystrophies in vivo.
Lluri
Gentian
G
Department of Anatomy and Neurobiology, University of Vermont College of Medicine, 149 Beaumont Ave., HSRF 418, Burlington, VT 05405, USA.
Langlois
Garret D
GD
Soloway
Paul D
PD
Jaworski
Diane M
DM
D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D048429:Cell Size; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D019012:Integrin beta1 / Q000235:genetics / Q000378:metabolism*; D053511:Matrix Metalloproteinase 14 / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D024510:Muscle Development / Q000187:drug effects / Q000502:physiology*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D032446:Myoblasts / Q000187:drug effects / Q000378:metabolism*; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics / Q000502:physiology*
D016895:Culture Media, Serum-Free; D019012:Integrin beta1; C507096:Mmp14 protein, mouse; D019716:Tissue Inhibitor of Metalloproteinase-2; D020778:Matrix Metalloproteinase 2; D053511:Matrix Metalloproteinase 14