The basal chorionic trophoblast cell layer: An emerging coordinator of placenta development

Abstract

During gestation, fetomaternal exchange occurs in the villous tree (labyrinth) of the placenta. Development of this structure depends on tightly coordinated cellular processes of branching morphogenesis and differentiation of specialized trophoblast cells. The basal chorionic trophoblast (BCT) cell layer that localizes next to the chorioallantoic interface is of critical importance for labyrinth morphogenesis in rodents. Gcm1-positive cell clusters within this layer initiate branching morphogenesis thereby guiding allantoic fetal blood vessels towards maternal blood sinuses. Later these cells differentiate and contribute to the syncytiotrophoblast of the fetomaternal barrier. Additional cells within the BCT layer sustain continued morphogenesis, possibly through a repopulating progenitor population. Several mouse mutants highlight the importance of a structurally intact BCT epithelium, and a growing number of studies addresses its patterning and epithelial architecture. Here, we review and discuss emerging concepts in labyrinth development focussing on the biology of the BCT cell layer.

Increased Expression of E-cadherin, Endothelin-1, and CD68 in Preeclamptic Placentas

“…Trophoblasts, which form the outer layer of the placenta, are divided into two layers: an underlying layer known as cytotrophoblasts and an overlying layer known as syncytiotrophoblasts (7)(8)(9). PE is associated with the impaired migration/invasiveness of trophoblasts, which leads to endothelial dysfunction, incomplete uterine vascular remodeling, and, consequently, poor placental perfusion.…”

“…In a normal pregnancy, the invasion of cytotrophoblasts results in remodeling of the uterine spiral arteries, which is required for placental perfusion. In PE, remodeling of the spiral arteries is impaired as a result of poor trophoblast migration/invasion (10,11). E-cadherin is an adherent junction protein expressed by epithelial tissues, which is important for the development of the embryo and the formation of cell-cell interactions via intracellular binding to catenins such as β-catenin, plakoglobin, and p120 catenin (12).…”

Expression of Endothelin-1 and Ki-67 in Normotensive and Severe Preeclamptic Placentas

“…In a normal pregnancy, the invasion of cytotrophoblasts results in remodeling of the uterine spiral arteries, which is required for placental perfusion. In Preeclampsia, remodeling of the spiral arteries is impaired as a result of poor trophoblast migration/invasion (Chaiworapongsa et al, 2014;Walentin et al, 2016).…”

Deregulation of c‐Src tyrosine kinase and its downstream targets in pre‐eclamptic placenta

“…The placenta consists of trophoblasts differentiated from blastocyst and endothelial cells and is the site for complex molecular interactions between maternal and fetal factors, such as gas and nutrient exchange, as well as waste elimination through the establishment of an adequate blood supply. [3][4][5] Trophoblasts, which form the outer layer of the placenta, are further divided into the underlying cytotrophoblasts and the overlying syncytiotrophoblast layers. 3,4 Migration and invasion of trophoblasts is important for placental development.…”

“…[3][4][5] Trophoblasts, which form the outer layer of the placenta, are further divided into the underlying cytotrophoblasts and the overlying syncytiotrophoblast layers. 3,4 Migration and invasion of trophoblasts is important for placental development. Particularly, the extravillous trophoblasts, an invasive sub-population of trophoblasts, migrate and invade through the decidua and then remodel the maternal spiral arteries.…”