Thrombospondin-1 and neural crest cell migration

Using a monoclonal antibody raised against human platelet thrombospondin, w e found anti-thrombospondin immunoreactivity in the extracellular matrix of avian embryos, coincident with the ventral pathways followed by trunk neur al crest cells. To confirm that the antibody recognized thrombospondin-l an d to determine the tissue of origin of the thrombospondin matrix, a thrombo spondin-l cRNA probe was used for whole mount in situ hybridization. This p robe revealed thrombospondin-l mRNAs in the developing myotome before and d uring neural crest cell migration. The effect of thrombospondin-l on neural crest cell migration, morphology, and adhesion was assayed in vitro. Quail trunk neural crest cells cultured on 4 mu g/ml of thrombospondin-l migrate at 1.14 -/+ 0.54 mu m/min, which is significantly greater than the rate of cell migration on tissue culture plastic. Using a shaker-based adhesion as say, a significantly greater number of neural crest cells remain attached t o dishes coated with 4 mu g/ml of thrombospondin-l than to tissue culture p lastic alone, The number of neural crest cells that remain attached to 4 mu g/ml of thrombospondin-l is similar to the number that remain attached to dishes coated with 10 mu g/ml of fibronectin. These observations indicate t hat neural crest cells migrate through a thrombospondin-filled extracellula r matrix, and that thrombospondin-l promotes neural crest cell migration an d adhesion. Thus, thrombospondin-l is the first somite-derived extracellula r matrix molecule with properties consistent with a role in the promotion o f migration into the anterior somite, as opposed to the repulsion of neural crest cells from the posterior half of the somite. Dev Dyn 1999;214:312-32 2. (C) 1999 Wiley-Liss,Inc.