FIGURE 6.

LTB₄ promotes synovial fibroblast migratory and invasive behavior. A, Lamellipodium formation in WT FLSs stimulated by LTB₄. WT FLSs were plated on coverslips and stimulated and stained as labeled. Nuclei are visualized with a Hoechst dye (blue). Arrows indicate lamellopodia in FLSs stimulated by LTB₄. Data are representative of three independent experiments. B, Percentage of FLSs demonstrating lamellipodium formation. The results represent the mean ± SEM of data pooled from three experiments. The p value was determined by the Student unpaired two-tailed t test. C, LTB₄-induced invasion of FLSs. Primary FLSs placed in Matrigel-coated transwell dishes were stimulated as labeled and cells migrating to the lower membrane surface were enumerated. Results shown are the mean ± SEM of data pooled from four independent experiments. D, LTB₄-induced invasion in FLSs requires BLT1 expression. WT or BLT1^–/– FLSs were placed in Matrigel-coated transwells and stimulated and enumerated as in C. E, BLT1 antagonist CP-105,696 inhibits LTB₄-driven FLS invasion. WT FLSs were pretreated with CP-105,696 for 30 min prior to measuring LTB₄- or PDGF-driven invasion as in C. Data shown in D and E are the mean ± SEM of data pooled from three experiments. The p value was determined by the Student unpaired two-tailed t test.