title: Disruption of the endothelial cell protein C receptor gene in mice causes placental thrombosis and early embryonic lethality.
abstract: The endothelial cell protein C receptor (EPCR) is a type 1 transmembrane protein found primarily on endothelium that binds both protein C and activated protein C with similar affinity. EPCR augments the activation of protein C by the thrombin-thrombomodulin complex. To determine the physiological importance of EPCR, we generated EPCR-deficient mice by homologous targeting in embryonic stem cells. Genotyping of progeny obtained from EPCR(+/-) interbreeding indicated that EPCR(-/-) embryos died on or before embryonic day 10.5 (E10.5). Reverse transcriptase-PCR confirmed the absence of EPCR mRNA in EPCR(-/-) embryos. EPCR(-/-) embryos removed from extra-embryonic membranes and tissues at day E7.5 and cultured in vitro developed beyond E10.5, suggesting a role for EPCR in the normal function of the placenta and/or at the materno-embryonic interface. Immunohistochemistry revealed the lack of EPCR in trophoblast giant cells of EPCR(-/-) embryos. These cells, which normally express EPCR, are in direct contact with the maternal circulation and its clotting factors. In EPCR(-/-) embryos, greatly increased fibrin deposition was detected around these cells. To prevent this fibrin deposition, EPCR(+/-)-crossed female mice received a daily subcutaneous injection of enoxaparin through pregnancy. Although some EPCR(-/-) embryos were rescued from midgestational lethality, this regimen yielded no EPCR(-/-) pups. We conclude that EPCR is essential for normal embryonic development. Moreover, EPCR plays a key role in preventing thrombosis at the maternal-embryonic interface.
authors.affiliation: Cardiovascular Biology, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA.
authors.forename: Jian-Ming
authors.initials: JM
authors.lastname: Gu
authors.forename: James T B
authors.initials: JT
authors.lastname: Crawley
authors.forename: Gary
authors.initials: G
authors.lastname: Ferrell
authors.forename: Fangjiu
authors.initials: F
authors.lastname: Zhang
authors.forename: Weihong
authors.initials: W
authors.lastname: Li
authors.forename: Naomi L
authors.initials: NL
authors.lastname: Esmon
authors.forename: Charles T
authors.initials: CT
authors.lastname: Esmon
mesh_terms: D000818:Animals; D001483:Base Sequence; D001779:Blood Coagulation Factors / Q000235:genetics* / Q000378:metabolism; D017931:DNA Primers; D004622:Embryo, Mammalian / Q000502:physiology; D005260:Female; D005313:Fetal Death; D005838:Genotype; D005865:Gestational Age; D051379:Mice; D018345:Mice, Knockout; D009924:Organ Culture Techniques; D010922:Placenta Diseases / Q000235:genetics* / Q000473:pathology; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics; D011956:Receptors, Cell Surface / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D013927:Thrombosis
chemical_list: D001779:Blood Coagulation Factors; D017931:DNA Primers; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C091963:activated protein C receptor