The effect of platelet-derived growth factor on morphology and motility of human glial cells.

Platelet-derived growth factor (PDGF) is a mitogen for several cell types in culture. It is documented in this work that one of the earliest effects of PDGF on serum-starved glial cells is an induction of intensive motile activity. Within the first minute after the addition of PDGF thin membrane lamellae grow out around almost all of the cell circumference. Later, circular arrangements of small ruffles appear on the dorsal surface of the cells. These rings of ruffles vary in size and some encircle almost the whole cell. The organization of the peripheral weave of microfilaments in the PDGF-induced advancing lamellae was closely similar to that of normally growing cells. In the regions of the circular arrangements of ruffles there was an extensive reorganization of the surface actin with unusual arrangements of microfilament bundles and polygonal networks. There was also a general intensification of the translocation of membrane ruffles and spikes from the cell periphery towards the centre of the cell, increased micropinocytotic activity and shuttling of intracellular particles.