TGF-ß₁ AND EGF IN THE PALATE OF Tgf-ß₃ NULL MICE

We have previously demonstrated interactions between TGF-ß1 and TGF-ß3 during palate development, and that the presence of both EGF and TGF-ß1 is altered in the Tgf-ß3 null mutant mouse (Tgf-ß3 -/-) palate, which shows cleft palate with reduced palatal shelf adhesion and fusion and medial edge epithelium (MEE) cell death. Objectives: The aim of this work has been to determine whether there are interactions between TGF-ß1 and EGF in Tgf-ß3 -/- mouse palates and whether the changes in the presence of EGF play any role in the reduced palatal shelf adhesion and fusion of these mice. Methods: We have performed cultures from embryonic day 13.5 Tgf-ß3 -/- isolated palatal shelves, adding either PBS (control) or TGF-ß1 and analyzed the presence of EGF by mean of immunohistochemistry. We also added either PBS (control) or Tyrphostin (which neutralices the EGF receptor) to 18 or 36 hour paired palatal shelf cultures and analyzed palatal shelf adhesion and fusion and the cell death occurring in the adhered opposing MEE. Results: Our results show changes in the presence of EGF in the palate of mice treated with TGF-ß1, thus indicating the existence of interactions between them, as well as a great increase in palatal shelf adhesion and fusion and MEE cell death in those cultures in which the EGF action was blocked. Conclusions: We thus conclude that in the Tgf-ß3 -/- mouse palate there are interactions between EGF and TGF-ß1, and that the changes observed in the presence of EGF in them have some responsibility in the reduction of palatal shelf adhesion and fusion and MEE cell death presented by these mice.

This work has been supported by a grant from Fondo de Investigación Sanitaria (PI06/0184) and Universidad Complutense de Madrid /BSCH in 2009.