title: 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.
authors.affiliation: Max Delbrück Center for Molecular Medicine, Berlin, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Walentin
authors.affiliation: Max Delbrück Center for Molecular Medicine, Berlin, Germany.|Department of Nephrology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Hinze
authors.affiliation: Max Delbrück Center for Molecular Medicine, Berlin, Germany.|Department of Nephrology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Kai M
authors.initials: KM
authors.lastname: Schmidt-Ott
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D016764:Cell Polarity; D049033:Chorioallantoic Membrane / Q000166:cytology / Q000201:enzymology; D002823:Chorion / Q000166:cytology*; D005260:Female; D006801:Humans; D009024:Morphogenesis; D010447:Peptide Hydrolases / Q000378:metabolism; D010920:Placenta / Q000166:cytology* / Q000502:physiology; D010929:Placentation; D011247:Pregnancy; D014327:Trophoblasts / Q000502:physiology*
chemical_list: D010447:Peptide Hydrolases
keywords: Rhox4b; Spint1; Spint2; basal chorionic trophoblast; basement membrane; branching morphogenesis; epithelial polarity; grainyhead-like 2 (Grhl2); labyrinth; placenta development