Fig. 6. Pre-treatment with HGF and M-CSF in resting osteoclasts promotes _vß₃ redistribution in membrane ruffles and lamellipodia. Primary human osteoclasts plated onto coverslips were preincubated with vehicle alone (A-C), HGF (5 ng/ml) (D-F) or M-CSF (0.5 nM) (G-J) and immunostained for total _vß₃ with AP3 and co-stained with FITC-phalloidin. Pseudocolor merged images from _vß₃ staining in red and actin in green have been examined. The typical distribution of _vß₃ in rosette-like structures around a core of actin filaments in the podosomes, detected by AP3 in vehicle-treated osteoclasts (A-C, arrowhead), has been replaced by a peripheral distribution in membrane ruffles and lamellipodia in (D-F, arrow) HGF- or (G-J, arrow) M-CSF-treated osteoclasts. Pre-incubation with wortmannin before growth factor treatment inhibited integrin mobilization to the membrane edges, and _vß₃ is still organized in rosette-like structures (K-M, arrowhead). Phalloidin staining (B,E,H,L) shows that the podosomes in all treated cells are still well organized. Wortmannin-treated cells also show filaments of cortical actin (L). Bar, 10 µm.

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