title: The expression of the placental anticoagulant protein, annexin V, by villous trophoblasts: immunolocalization and in vitro regulation.
abstract: We evaluated the histological and ultrastructural localization of the potent anticoagulant protein, annexin V, at the light and electron microscopic levels, using immunohistochemistry and an immunogold method. Annexin V was found to localize to the microvillar surface of the villous syncytiotrophoblasts. Isolated villous-derived trophoblasts were then utilized to evaluate the expression of annexin 1 protein mRNA in response to syncytialization in vitro, as well as to exposure to adenylate cyclase and protein kinase C agonists. Levels of immunoreactive annexin V released into the conditioned media and associated with cell protein were assessed by ELISA while levels of annexin V mRNA were evaluated by Northern analysis. No significant change in either media or cell-associated annexin V concentrations were detected over time in culture or in response to 1.5 mM 8-bromo-cyclic-adenosine-monophosphate (8-b-cAMP) or 0.15 nM phorbol ester myristic acid (PMA). These results indicate that annexin V is ideally positioned to inhibit intervillous thrombosis and maintain the fluidity of the intervillous circulation. Moreover, the absence of trophoblast annexin V regulation by intracellular second messenger regulators suggests that this crucial placental anticoagulant factor is constitutively produced.
authors: Department of Obstetrics, Gynecology, Mount Sinai School of Medicine, New York, NY 10029.
authors: G
authors: G
authors: Krikun
authors: C J
authors: CJ
authors: Lockwood
authors: X X
authors: XX
authors: Wu
authors: X D
authors: XD
authors: Zhou
authors: S
authors: S
authors: Guller
authors: C
authors: C
authors: Calandri
authors: A
authors: A
authors: Guha
authors: Y
authors: Y
authors: Nemerson
authors: J H
authors: JH
authors: Rand
mesh_terms: D017304:Annexin A5 / Q000032:analysis* / Q000235:genetics / Q000502:physiology*; D015152:Blotting, Northern; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D016253:Microscopy, Immunoelectron; D011247:Pregnancy; D011493:Protein Kinase C / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D015290:Second Messenger Systems / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014327:Trophoblasts / Q000737:chemistry* / Q000166:cytology / Q000648:ultrastructure
chemical_list: D017304:Annexin A5; D012333:RNA, Messenger; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate