Int. J. Dev. Biol. 54: 737 - 742 (2010)
Dynamic expression of Endoglin, a TGF-beta co-receptor, during pre-circulation vascular development in chick
Developmental Expression Pattern | Published: 20 November 2009
Abstract
Mutations in the human Endoglin gene, encoding a dimeric TGF-beta co-receptor, lead to type 1 hereditary hemorrhagic telangiectasia. Studies in mice have revealed important roles of Endoglin in endothelial cell proliferation, differentiation and integrity. Endoglin -/- mouse embryos die at mid-gestation due to cardiac defects and vessel rupture. Its role during early vasculogenesis is unclear, as the initial phase of vascular endothelial cell formation appears unaffected in Endoglin -/- embryos. In order to understand possible roles of Endoglin in early vascular development, we used the chick model and analyzed the temporal and spatial expression pattern of Endoglin during vasculogenesis in pre-circulation stage chick embryos. Weak Endoglin expression was detected at HH4 in the node and in the extraembryonic mesoderm. The node-specific expression is transitory and disappears after HH5. Strong up-regulation of Endoglin expression is seen at HH8 in all endothelial progenitors undergoing morphological changes to become endothelial cells. Most extraembryonic splanchnopleural vascular endothelial cells down-regulate Endoglin after their morphological differentiation, whereas lateral plate and cardiac endothelial cells remain positive until HH12, followed by a clear drop after circulation starts at HH13. Progenitors for the pronephric duct are positive from HH10 to HH12, but down-regulate Endoglin after epithelialization of duct cells. Overall, these data reveal a dynamic expression pattern of Endoglin in pre-circulation chick development and indicate that Endoglin may play an important role in the transition from endothelial progenitors to functional endothelial cells during early vascular development.
Keywords
CD105, vasculogenesis, vasculature, endothelial cell, hematopoiesis, progenitor, chicken