title: Distinctive functions of membrane type 1 matrix-metalloprotease (MT1-MMP or MMP-14) in lung and submandibular gland development are independent of its role in pro-MMP-2 activation.
abstract: Membrane type 1-matrix metalloprotease (MT1-MMP or MMP-14) is a major activator of pro-MMP-2 and is essential for skeletal development. We show here that it is required for branching morphogenesis of the submandibular gland but not the lung. Instead, in the lung, it is essential for postnatal development of alveolar septae. Lung development in Mmp14-/- mice is arrested at the prealveolar stage with compensatory hyperinflation of immature saccules. Mmp2-/- mice lacked comparable defects in the lung and submandibular gland, suggesting that MT1-MMP acts via mechanisms independent of pro-MMP-2 activation. Since the developmental defects in the lung are first manifest around the time of initial vascularization (E16.5), we investigated the behavior of pulmonary endothelial cells from Mmp14+/+ and Mmp14-/- mice. Endothelial cells from lungs of 1-week-old Mmp14-/- mice show reduced migration and formation of three-dimensional structures on Matrigel. Since pulmonary septal development requires capillary growth, the underlying mechanism of pulmonary hypoplasia in Mmp14-/- mice may be defective angiogenesis, supporting a model in which angiogenesis is a critical rate-limiting step for acquisition of pulmonary parenchymal mass.
authors.affiliation: Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
authors.forename: Samantha A
authors.initials: SA
authors.lastname: Oblander
authors.forename: Zhongjun
authors.initials: Z
authors.lastname: Zhou
authors.forename: Beatriz G
authors.initials: BG
authors.lastname: Gálvez
authors.forename: Barry
authors.initials: B
authors.lastname: Starcher
authors.forename: John M
authors.initials: JM
authors.lastname: Shannon
authors.forename: Madeleine
authors.initials: M
authors.lastname: Durbeej
authors.forename: Alicia G
authors.initials: AG
authors.lastname: Arroyo
authors.forename: Karl
authors.initials: K
authors.lastname: Tryggvason
authors.forename: Suneel S
authors.initials: SS
authors.lastname: Apte
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism*; D008168:Lung / Q000196:embryology* / Q000648:ultrastructure; D053511:Matrix Metalloproteinase 14; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008855:Microscopy, Electron, Scanning; D009024:Morphogenesis; D013363:Submandibular Gland / Q000196:embryology* / Q000648:ultrastructure
chemical_list: D004792:Enzyme Precursors; C507096:Mmp14 protein, mouse; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2; D053511:Matrix Metalloproteinase 14