title: Fibulin-5 expression in the human placenta.
abstract: Fibulin-5 is a secreted extracellular matrix glycoprotein and displays a diverse panel of biological functions, which can be segregated into elastogenic as well as extra-elastogenic functions. While elastogenic functions of fibulin-5 include essential roles in early steps of elastic fibre assembly, extra-elastogenic functions are widespread. Depending on the cell type used, fibulin-5 mediates cell adherence via a subset of integrins, antagonizes angiogenesis and inhibits migration as well as proliferation of endothelial and smooth muscle cells. In this study, we focused on the spatiotemporal expression of fibulin-5 in the human placenta. With progressing gestation, placental fibulin-5 expression increased from first trimester towards term. At term, placental fibulin-5 mRNA expression is lower when compared with other well-vascularized organs such as lung, kidney, heart, uterus and testis. In first trimester, placenta immunohistochemistry localized fibulin-5 in villous cytotrophoblasts and extravillous cytotrophoblasts of the proximal cell column. In term placenta, fibulin-5 was detected in the endothelial basement membrane and adventitia-like regions of vessels in the chorionic plate and stem villi. Cell culture experiments with the villous trophoblast-derived cell line BeWo showed that fibulin-5 expression was downregulated during functional differentiation and intercellular fusion. Moreover, cultivation of BeWo cells under low oxygen conditions impaired intercellular fusion and upregulated fibulin-5 expression. The spatiotemporal shift from the trophoblast compartment in first trimester to the villous vasculature at term suggests a dual role of fibulin-5 in human placental development.
authors.affiliation: Institute of Cell Biology, Histology and Embryology, Center for Molecular Medicine, Medical University of Graz, Harrachgasse 21/7, 8010 Graz, Austria. martin.gauster@medunigraz.at
authors.forename: Martin
authors.initials: M
authors.lastname: Gauster
authors.forename: Veronika M
authors.initials: VM
authors.lastname: Berghold
authors.forename: Gerit
authors.initials: G
authors.lastname: Moser
authors.forename: Kristina
authors.initials: K
authors.lastname: Orendi
authors.forename: Monika
authors.initials: M
authors.lastname: Siwetz
authors.forename: Berthold
authors.initials: B
authors.lastname: Huppertz
mesh_terms: D002460:Cell Line; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D010920:Placenta / Q000378:metabolism*; D010929:Placentation; D011247:Pregnancy; D011264:Pregnancy Trimesters; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D016326:Extracellular Matrix Proteins; C492373:FBLN5 protein, human; D012333:RNA, Messenger