Chemotactic migration of mesencephalic neural crest cells in the mouse

Dev Dyn. 2000 Feb;217(2):170-9. doi: 10.1002/(SICI)1097-0177(200002)217:2<170::AID-DVDY4>3.0.CO;2-9.

Abstract

We examined the roles of fibroblast growth factor (FGF)-2 and FGF-8 in the migration of mesencephalic mouse neural crest cells. Our in vitro migration assay has shown that FGF-2 (basic FGF) and FGF-8 have chemotactic activity for these cells. Chemotaxis was inhibited by anti-FGF-2 and anti-FGF-8 neutralizing antibodies. In addition, anti-FGF-2 blocked neural crest cell migration in cranial organ cultures. This observation suggests that FGF-2 functions as a chemoattractant in migration of mesencephalic neural crest cells in vivo. In organ culture, the antagonist of FGF binding to a low-affinity fibroblast growth factor receptor (FGFR) heparan sulfate, inositolhexakisphosphate (InsP6), inhibited migration as well. Mesencephalic neural crest cells had high-affinity FGFRs, in particular FGFR-1 and FGFR-3. Thus, the chemotactic activities of FGF-2 can be mediated by the low-affinity FGFR alone or by a combination of low- and high-affinity FGFRs (FGFR-1, FGFR-3, or both). Moreover, differential localization of FGF-2 was found at the mesencephalic axial level of intact embryos during neural crest cell migration. FGF-2 protein expression was predominant in the target regions, in particular the mandibular mesenchyme, that are colonized by mesencephalic neural crest cells. This characteristic distribution supports the notion that FGF-2 acts as a chemoattractant in the mouse embryo that directs mesencephalic neural crest cell migration. Whereas FGF-8 showed chemotactic activity in vitro, neural crest cell dispersion was observed in explants that had been treated with anti-FGF-8 neutralizing antibodies. This result suggests that FGF-8 may not be a chemoattractant in vivo. However, the distribution of neural crest cells in explants treated with anti-FGF-8 differed from that in control explants or in intact embryos. Extreme FGF-2 distribution was observed in the mandibular arch and FGF-8 is expressed in the epithelium. FGF-8 may play a role in mesencephalic neural crest cell migration, and its role may be concerned with the differential localization of FGF-2. To establish this notion, we performed immunohistochemical examination of FGF-2 distribution in explants treated with FGF-8 and analysis of FGF-2 gene expression levels by reverse transcriptase-polymerase chain reaction by using RNA from explants. The data indicate that FGF-2 is distributed throughout the mesenchyme in FGF-8-treated explants and that expression of FGF-2 is promoted by FGF-8. Therefore, we conclude that the expression of FGF-8 in the mandibular arch epithelium is a prerequisite for the differential localization of FGF-2 and that the FGF-2 distribution pattern is essential for chemotaxis of mesencephalic neural crest cell migration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chemotaxis / drug effects
  • Chemotaxis / physiology*
  • Fibroblast Growth Factor 2 / metabolism
  • Fibroblast Growth Factor 2 / physiology*
  • Fibroblast Growth Factor 8
  • Fibroblast Growth Factors / metabolism
  • Fibroblast Growth Factors / physiology*
  • Mesencephalon / cytology
  • Mice
  • Neural Crest / cytology*
  • Neutralization Tests
  • Organ Culture Techniques
  • Phytic Acid / metabolism
  • Phytic Acid / pharmacology
  • Protein-Tyrosine Kinases*
  • Receptor Protein-Tyrosine Kinases / metabolism
  • Receptor, Fibroblast Growth Factor, Type 1
  • Receptor, Fibroblast Growth Factor, Type 2
  • Receptor, Fibroblast Growth Factor, Type 3
  • Receptor, Fibroblast Growth Factor, Type 4
  • Receptors, Fibroblast Growth Factor / metabolism

Substances

  • Fgf8 protein, mouse
  • Receptors, Fibroblast Growth Factor
  • Fibroblast Growth Factor 2
  • Fibroblast Growth Factor 8
  • Fibroblast Growth Factors
  • Phytic Acid
  • Fgfr1 protein, mouse
  • Fgfr2 protein, mouse
  • Fgfr3 protein, mouse
  • Fgfr4 protein, mouse
  • Protein-Tyrosine Kinases
  • Receptor Protein-Tyrosine Kinases
  • Receptor, Fibroblast Growth Factor, Type 1
  • Receptor, Fibroblast Growth Factor, Type 2
  • Receptor, Fibroblast Growth Factor, Type 3
  • Receptor, Fibroblast Growth Factor, Type 4