Figure 2. Inhibiting macrophage movement with latrunculin A or blebbistatin abolishes particle release onto the surrounding substrate.
Scanning electron micrographs (SEMs) of mouse peritoneal macrophages that had been treated with latrunculin A (A) or blebbistatin (B). Macrophages were treated with latrunculin A, blebbistatin, or vehicle alone (DMSO) overnight; the drug treatments were initiated when the cells were in suspension 1 h before plating ('pre-treatment') or 1 h after adherence to the substrate ('post-adherence'). Macrophages treated with vehicle alone (DMSO) released particles onto the substrate. No particles were visible on the substrate in cells that had been pre-treated with latrunculin A or blebbistatin—or in the blebbistatin post-adherence cells. In the latrunculin A post-adherence cells, a circumferential ring of particles was observed around cells. Latrunculin A and blebbistatin were removed from some dishes after the overnight incubation, and the cells were incubated for an additional 18 h without drugs. After removing the drugs, the release of particles onto the substrate resumed. Four independent experiments were performed; representative images are shown. Scale bars for images on the left in each panel are 4 µm; scale bars for the images in the middle and right are 1 µm.
