The Role of Neural Crest Cells During Trigeminal Morphogenesis

Objective: A number of trigeminal nerve-related congenital defects, diseases, and injuries can severely hinder the quality of life in many patients. Understanding molecular and cellular mechanisms that pattern the trigeminal could lead to novel therapies for inducing repair and regeneration of this important nerve. This study investigates the role of cranial neural crest cells during trigeminal morphogenesis.

Methods: To assess the role of cranial neural crest cells on the timing of differentiation and patterning of the trigeminal ganglion, an avian transplantation system that exploits the divergent maturation rates and distinct species-specific anatomies of quail and duck was used. First, to define normal trigeminal morphogenesis, embryos of Japanese quail and White Pekin duck were collected at different developmental stages. Trigeminal nerve morphology was evaluated by whole mount immunostaining and immunostaining on sections using a neurofilament-specific antibody (3A10). Second, cranial neural crest was unilaterally and homotopically grafted from quail embryos to stage matched duck embryos. Trigeminal development in chimeras was compared to development in control quail and duck by 3D reconstruction and 3A10 whole mount immunostaining.

Results: Species-specific differences in trigeminal nerve morphogenesis were observed, most notably a relatively more massive trigeminal ganglion in duck. Results show a less robust trigeminal ganglion on the donor side in duck embryos after transplantation of quail cranial neural crest, which could be indicative of a donor (quail)-specific development.

Conclusion: These findings support previous comparable experiments, which have shown the important role of neural crest cells in spatiotemporal patterning of cranial feather buds and beak morphology in quail and duck, and suggest that neural crest cells play a major role in the spatiotemporal development of the trigeminal nerve.

Support: PACCTR, Training Grant TL1-RR024129 to A.S.G.; NIDCR R03 DE014795 and R01 DE016402, and March of Dimes 5-FY04-26 to R.A.S.