title: Nodal signals through activin receptor-like kinase 7 to inhibit trophoblast migration and invasion: implication in the pathogenesis of preeclampsia.
abstract: Trophoblast cell invasion into the uterus is an essential process for successful pregnancy, and shallow invasion of trophoblasts into the maternal decidua is linked to preeclampsia. We have reported that Nodal, a member of the transforming growth factor-β superfamily, acts through activin receptor-like kinase 7 (ALK7) to inhibit trophoblast proliferation and to induce apoptosis. In this study, we examined the spatial and temporal expression patterns of Nodal and ALK7 in human placenta from normal and preeclamptic pregnancies and investigated whether Nodal regulated trophoblast migration and invasion. Nodal and ALK7 were detected in villous and extravillous trophoblast cell populations in early gestation, and their levels were strongly up-regulated in preeclamptic placenta. Overexpression of Nodal or constitutively active ALK7 decreased cell migration and invasion, whereas knockdown of Nodal and ALK7 had the opposite effects. In placental explant culture, treatment with Nodal inhibited trophoblast outgrowth, whereas Nodal small-interfering RNA strongly induced the expansion of explants and the migration of extravillous trophoblast cells. Nodal stimulated the secretion of tissue inhibitor of metalloproteinase-1 and inhibited matrix metalloproteinase (MMP)-2 and MMP-9 activity. These findings suggest that the Nodal/ALK7 pathway plays important roles in human placentation and that its abnormal signaling may contribute to the development of preeclampsia.
authors.affiliation: Department of Biology, York University, Toronto, Ontario, Canada.
authors.forename: Lubna
authors.initials: L
authors.lastname: Nadeem
authors.forename: Sadia
authors.initials: S
authors.lastname: Munir
authors.forename: Guodong
authors.initials: G
authors.lastname: Fu
authors.forename: Caroline
authors.initials: C
authors.lastname: Dunk
authors.forename: Dora
authors.initials: D
authors.lastname: Baczyk
authors.forename: Isabella
authors.initials: I
authors.lastname: Caniggia
authors.forename: Stephen
authors.initials: S
authors.lastname: Lye
authors.forename: Chun
authors.initials: C
authors.lastname: Peng
mesh_terms: D030201:Activin Receptors, Type I / Q000378:metabolism*; D002465:Cell Movement; D005260:Female; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D055457:Nodal Protein / Q000378:metabolism*; D010920:Placenta / Q000201:enzymology / Q000473:pathology; D010929:Placentation; D011225:Pre-Eclampsia / Q000201:enzymology / Q000209:etiology* / Q000378:metabolism; D011247:Pregnancy; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D014327:Trophoblasts / Q000201:enzymology* / Q000473:pathology*
chemical_list: D055457:Nodal Protein; D034741:RNA, Small Interfering; D019715:Tissue Inhibitor of Metalloproteinase-1; C498932:ACVR1B protein, human; C424205:ACVR1C protein, human; D030201:Activin Receptors, Type I; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9