title: Alterations in membrane type-1 matrix metalloproteinase abundance after the induction of thoracic aortic aneurysm in a murine model.
abstract: Thoracic aortic aneurysms (TAAs) develop as a result of dysregulated extracellular matrix remodeling mediated by several matrix metalloproteinases (MMPs). Membrane type-1 MMP (MT1-MMP) is the prototypical member of a unique family of membrane-bound MMPs, possessing multiple substrates and functions. The present study tested the hypothesis that MT1-MMP expression, abundance, and activity would be elevated during TAA development and that this protease is produced primarily by mesenchymal cells within the thoracic aorta. Descending thoracic aortas were harvested from C57BL/6J mice at multiple time points (2, 4, 8, and 16 wk, n = 15 each) post-TAA induction (0.5M CaCl(2), 15 min) and compared with reference controls (n = 15). The expression and abundance of MT1-MMP, MMP-2, and tissue inhibitor of metalloproteinase (TIMP)-2 were assessed by quantitative PCR and immunoblot analysis. MT1-MMP activity was determined by fluorescent peptide assay. MT1-MMP was localized within the aortic wall by immunohistochemistry. MT1-MMP abundance and localization in live animals (8 wk post-TAA induction vs. control) was determined by micro-ultrasound imaging with an MT1-MMP-targeted microbubble contrast agent. Aortic diameter was increased 172 +/- 7% at 16 wk post-TAA induction (P < 0.05). MT1-MMP and MMP-2 mRNA levels were elevated at 2 wk post-TAA induction (P < 0.05). MT1-MMP protein abundance increased progressively to a maximum of 178 +/- 26% at 16 wk post-TAA induction, whereas MMP-2 and TIMP-2 peaked at 2 wk post-TAA induction (526 +/- 93% and 376 +/- 48%, respectively, P < 0.05). MT1-MMP colocalized with fibroblasts, and MT1-MMP-targeted contrast binding was elevated in 8-wk TAA-induced mice versus control mice (217 +/- 53% vs. 81 +/- 8%, P < 0.05). In conclusion, these novel results suggest that MT1-MMP plays a dynamic multifunctional role in TAA development and, therefore, may provide a significant target for therapeutic strategies.
authors.affiliation: Division of Cardiothoracic Surgery Research, Department of Surgery, Medical University of South Carolina, 114 Doughty Street, Charleston, SC 29425, USA.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Jones
authors.forename: Jean Marie
authors.initials: JM
authors.lastname: Ruddy
authors.forename: Shenikqua
authors.initials: S
authors.lastname: Bouges
authors.forename: Juozas A
authors.initials: JA
authors.lastname: Zavadzkas
authors.forename: Theresa A
authors.initials: TA
authors.lastname: Brinsa
authors.forename: Robert E
authors.initials: RE
authors.lastname: Stroud
authors.forename: Rupak
authors.initials: R
authors.lastname: Mukherjee
authors.forename: Francis G
authors.initials: FG
authors.lastname: Spinale
authors.forename: John S
authors.initials: JS
authors.lastname: Ikonomidis
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging / Q000201:enzymology*; D017545:Aortic Aneurysm, Thoracic / Q000139:chemically induced / Q000000981:diagnostic imaging / Q000201:enzymology* / Q000235:genetics; D015153:Blotting, Western; D002122:Calcium Chloride; D003287:Contrast Media; D004108:Dilatation, Pathologic; D004195:Disease Models, Animal; D005260:Female; D005347:Fibroblasts / Q000201:enzymology; D015971:Gene Expression Regulation, Enzymologic; D007150:Immunohistochemistry; D008297:Male; D053511:Matrix Metalloproteinase 14 / Q000235:genetics / Q000378:metabolism*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D045423:Microbubbles; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism; D014463:Ultrasonography; D015854:Up-Regulation
chemical_list: D003287:Contrast Media; C507096:Mmp14 protein, mouse; D012333:RNA, Messenger; D019716:Tissue Inhibitor of Metalloproteinase-2; D020778:Matrix Metalloproteinase 2; C522362:Mmp2 protein, mouse; D053511:Matrix Metalloproteinase 14; D002122:Calcium Chloride