Title | Exposure of cryptic domains in the alpha 1-chain of laminin-1 by elastase stimulates macrophages urokinase and matrix metalloproteinase-9 expression. |
Publication Type | Journal Article |
Year of Publication | 2002 |
Authors | Khan KMFaisal, Laurie GW, McCaffrey TA, Falcone DJ |
Journal | J Biol Chem |
Volume | 277 |
Issue | 16 |
Pagination | 13778-86 |
Date Published | 2002 Apr 19 |
ISSN | 0021-9258 |
Keywords | Animals, Aortic Aneurysm, Arginine, Blotting, Western, Cattle, Cell Line, Chromatography, Fibrinolysin, Humans, Laminin, Macrophages, Matrix Metalloproteinase 2, Matrix Metalloproteinase 7, Matrix Metalloproteinase 9, Mice, Pancreatic Elastase, Peptides, Phosphorylation, Protein Kinase C, Protein Structure, Tertiary, Serine, Time Factors, Urokinase-Type Plasminogen Activator |
Abstract | Degradation of the extracellular matrix leads to the release of fragments, which elicit biological responses distinct from intact molecules. We have reported that alpha1:Ser(2091)-Arg(2108), a peptide derived from the alpha1-chain of laminin-1, triggers protein kinase C-dependent activation of MAPK(erk1/2), leading to the up-regulation of macrophage urokinase type plasminogen activator and matrix metalloproteinase (MMP)-9 expression. Since intact laminin-1 failed to trigger these events, we hypothesized that alpha1:Ser(2091)-Arg(2108) is cryptic or assumes a conformation not recognized by macrophages. Here we demonstrate that elastase cleavage of laminin-1 generates fragments, which stimulate proteinase expression by RAW264.7 macrophages and peritoneal macrophages. In contrast, fragments generated by MMP-2, MMP-7, or plasmin had no effect on macrophage proteinase expression. Elastase-generated laminin-1 fragments were fractionated by heparin-Sepharose chromatography. Heparin-binding fragments stimulated macrophages' proteinase expression severalfold greater than nonbinding fragments. The heparin binding fragments reacted with antibodies directed against regions of the alpha1-chain including alpha1:Ser(2091)-Arg(2108) and the globular domain. A peptide from the first loop of the globular domain (alpha1:Ser(2179)-Ser(2198)) triggered the phosphorylation of MAPK(erk1/2) and stimulated the expression of macrophage urokinase type plasminogen activator and MMP-9. Moreover, a heparin-binding fraction isolated from an aortic aneurysm contained fragments of alpha1-chain and stimulated macrophages' proteinase expression. Based on these data, we conclude that cryptic domains in the COOH-terminal portion of the alpha1-chain of laminin are exposed by proteolysis and stimulate macrophages' proteinase expression. |
DOI | 10.1074/jbc.M111290200 |
Alternate Journal | J Biol Chem |
PubMed ID | 11827968 |
Grant List | R01 EY009747-08 / EY / NEI NIH HHS / United States R01-AG12712 / AG / NIA NIH HHS / United States R01-HL40819 / HL / NHLBI NIH HHS / United States R01-EY09747 / EY / NEI NIH HHS / United States |
Related Faculty:
Domenick J. Falcone, Ph.D.