Fig. 5.

Determination of molecules that mediate fibroblast attachment to vitronectin, fibronectin, and collagen. A: specific integrins that mediate fibroblast attachment. Fibroblasts were incubated with function-blocking antibodies against indicated integrins or serotype-matched IgGs at room temperature for 20 min with gentle rocking. Cell attachment to either vitronectin (5 μg/ml)-, fibronectin (10 μg/ml)-, or collagen (10 μg/ml)-coated tissue culture plastic microplate wells (15–30 min, 37°C, 5% CO₂). Results are expressed as percent attachment of IgG-pretreated cells. Values are means ± SD for n = 4/condition. *P < 0.05, compared with IgG control. B: role of u-PAR and u-PAR-integrin interactions in fibroblast attachment. Cells were incubated with indicated reagents (IgG control or u-PAR antibodies) or integrin-homologous peptides (α₃₂₅) or scrambled peptides [serum-containing medium (SCM)], and cell attachment was measured as described above. Results are expressed as percent attachment of either IgG- or vehicle (DMSO)-treated cells. Values are mean ± SD for n = 4/condition. *P < 0.05, compared with IgG or vehicle control. C: lack of effect of integrin-homologous peptides (α₃₂₅) on lung fibroblasts that are devoid of u-PAR. Murine lung fibroblast from u-PAR knockout mice were incubated with integrin-homologous peptides (α₃₂₅) or scrambled peptides (SCM) and assayed for their effects on attachment to vitronectin, fibronectin, and collagen, as in B. Values are means ± SD for n ≥ 4/condition.