Differentiation stage and cell cycle position determine the chemotactic response of fibroblasts

Human diploid fibroblasts can migrate in vitro towards a variety of chemoattractants, including proteins of the extracellular matrix and certain growth factors. Fibroblasts of various differentiation stages differ according to morphology as well as biochemical and cell biological criteria. We have in the present investigation compared defined differentiation stages of human dermal and lung fibroblasts with respect to their chemotactic responsiveness towards platelet-derived growth factor and a fragment of fibronectin. Proliferating mitotic fibroblast cell type MF II migrated whilst mitotic cell type MF III, postmitotic cell types PMF IV, PMF V, PMF VI, and mitotic cell types made quiescent by serum starvation or contact inhibition did not. Transformed cells could still respond to proteins of the extracellular matrix but not to growth factors. It is believed that these observations pertain to the situation in vivo and thus reveal an additional level of regulation during remodelling of connective tissues.