IP3R1 and IP3R2 deletion in the epiblast causes placental defects.
(A) Whole mount lacZ staining and transverse sections counterstained with nuclear fast red in E9.5 Meox2-Cre/Rosa-lacZ embryos and placentas. Low and high magnification views of the umbilical cord were presented to highlight the contribution of Meox2-Cre derived cells in the umbilical cord and placenta. em, embryo; pl, placenta; uc, umbilical cord; ma, maternal decidua; ch, chorion; gc, trophoblast giant cell; sp, spongiotrophoblast; la, labyrinth; en, endothelial cell; tp, trophoblast cell; me, mesenchymal cell. Black bar represents 0.4 mm. (B) Whole-mount assessment of E10.5 control and Meox2-Cre+Itpr1f/fIptr2-/- (cKOMeox2) embryos. The diameter of the umbilical cord is outlined by two parallel dotted yellow lines. Please note chest edema (yellow arrow) in cKOMeox2 embryos. (C) Histological analysis of placental sections from E10.5 cKOMeox2 and control embryos by H&E staining, at low (left) and high (right) magnification views. Trophoblast giant cell (gc), spongiotrophoblast (sp) and labyrinth (la) layers as well as chorion (ch) are shown within the placentas. The depth of the labyrinth is depicted by a vertical yellow bar. Yellow arrows denote the nucleated fetal blood cells. Black bar represents 0.4 mm (left) and 0.1 mm (right). (D) Quantitative analysis showing that the depth of the labyrinth is significantly reduced in E10.5 cKOMeox2 placentas (n = 6) when compared with control placentas (n = 6). All data represent mean ± SEM. Significance was determined by two-tailed, unpaired Student’s t-test. ***p < 0.001 versus control.