Ligation of protease-activated receptor 1 enhances α_v β₆ integrin–dependent TGF-β activation and promotes acute lung injury
J. Clin. Invest. R. Gisli Jenkins, et al. 116:1606 doi:10.1172/JCI27183 [Go to this article.]

Figure 4
PAR1 peptide–induced α_v β₆ -dependent TGF-β activity is PAR1 receptor specific. (A) α_vβ₆-dependent TGF-β activity following stimulation of mouse embryonic fibroblast cells, stably transfected with human WT β₆, with increasing doses of the PAR1-activating peptides TFLLRN and SFLLRN or the scrambled peptide control (FSLLRN), which has no known PAR1-activating effect. α_vβ₆-dependent TGF-β activity was calculated from coculture bioassays with TML cells, by comparison of the difference in luciferase activity in the absence and presence of α_vβ₆ blocking antibody with values obtained from a standard curve performed in coculture experiments with increasing concentrations of recombinant TGF-β. (B) After infection with a retroviral vector expressing WT human β₆, α_vβ₆ expression in lung fibroblasts from Par1^–/– mice that were either null (Par1^–/–) or reconstituted with WT PAR1 (Par1+) was assessed by flow cytometry. (C) α_vβ₆-expressing Par1^–/– and Par1+ fibroblasts were stimulated with increasing doses of SFLLRN, and α_vβ₆-dependent TGF-β activity was measured by coculture bioassay.