Effects of Phorbol Esters on Endothelial Cell Microfilaments: Laser Scanning Confocal Microscopy and Quantitative Morphometry of Dose Dependent Changes.

摘要

Phorbol esters are known to alter microfilaments but it is not clear if the changes correspond to modulation of the phosphoinositide turnover/protein kinase C system. The novel technique of laser scanning confocal epifluorescence was used to study fiber orientation in phorbol ester treated cells. We treated endothelial cells with control agents and agents known to stimulate protein kinase C. After incubation with the test agents, the endothelial cell microfilaments were stained with rhodamine pholloidin and viewed by conventional epifluorescence and by laser scanning confocal epifluorescence microscopy. After exposure of the cells to phorbol esters, the stress fibers became more nearly parallel in arrangement or were shortened, but remained in the plane of focus. Lipopolysaccharide was ineffective in inducing a morphological change under these conditions. A simple activation of protein kinase C is insufficient to explain the dose-dependent effects of phorbol esters. Thus a morphometric analysis can help distinguish the potency of cytoskeleton modulators. Keywords: Morphometric analysis, Laser scanning confocal microscopy, Fluorescence microscopy, phosphoinositide turnover, Lipopolysaccaride, Reprints. (kt)