Effects of neurotrophins on neural crest and Schwann cell migration

Abstract

The neural crest is a migratory population of cells that gives rise to a wide range of cell types in the peripheral nervous system of vertebrate embryos. It has been shown that neural crest cells migrate along very specific pathways throughout the embryo. The reason for such specificity is not fully known. During the last years, some known axon pathfinding repellants (ephrinB2, SemaIIIa, Slit2, etc) have been shown to repel neural crest cells as well during their migration through the somites. However, we know very little about the migratory clues that guide the neural crest for the rest of their path. The goal of this study was to find which other molecules are capable of guiding the neural crest. For this purpose we had set out to screen a group of neurotrophic factors that are expressed at the same time that the crest is migrating through the embryo. Our aim was to look at the effect of neurotrophins on neural crest migration and Schwann cell precursors. Experiments by live imaging in special chambers suggest that: a) neural crest cells are attracted to glia derived neurotrophic factor (GDNF) and Heregulinb1; and b) that Schwann cell precursors increase their speed in the presence of GDNF, NGF, Heregulinb1 and Macrophage inhibitory factor (MIF). These preliminary data suggests that neural crest and Schwann cells use a variety of neurotrophic factors as guiding clues during their extensive migration in the embryo.

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