Stem cell factor combined with matrix proteins regulates the attachment and migration of melanocyte precursors of human hair follicles in vitro.

In conjunction with matrix proteins, stem cell factor (SCF) plays an important role in the migration of melanocyte precursors (MPs) derived from the mouse embryo. However, no studies have demonstrated an effect of SCF on human follicular MPs migration in vitro. In this report, first we demonstrate the immature state of the follicular MPs. Then cell attachment rate was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Standard 48-well chemotaxis chambers were used for a transfilter migration assay. F-actin was labeled by rhodamine-conjugated phalloidin, and then organization of the actin cytoskeleton was observed by confocal microscope. In the results, we directly show that MPs adhere more strongly to fibronectin (FN), laminin (LN) and type IV collagen (CIV) than to the negative control. SCF decreased the adhesion of MPs to FN and CIV. A chemotaxis analysis showed that FN and CIV have chemotactic effects on MPs. FN showed an obvious increase in chemotactic effects on MPs with SCF treatment comparing with the control group, but there were no significant changes in the levels of chemotaxis with CIV and LN when the cells were treated with SCF. SCF was chemotactic to MPs, and the presence of FN caused a statistically significant increase in MPs migration at various concentrations of SCF. Furthermore, we showed that SCF, in combination with FN, could induce an apparent increase in actin stress fiber formation in MPs. Our results indicate that SCF, in combination with matrix proteins and in particular with FN, regulates the movement of MPs by both altering cell attachment and increasing cell chemotaxis.