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Hepatocyte growth factor and its receptor c-met: Localization and expression in the human placenta
Abstracts:
R.T.C.
and T.G.W.M.S.
Canada
A.37
1996
Hepatocyte Growth Factor and its Receptor c-met: Localization and Expressionin the Human Placenta. D.E. Clark, S.K. Smith, A.M. Sharkey,and D.S. Charnock-Jones. Reproductive Molecular ResearchGroup, Department of Obstetricsand Gynaecology, University of Cambridge, Rosie Maternity Hospital, Cambridge, CB2 2SW, U.K. Hepatocyte growth factor (HGF), acting via its c-met receptor, is known to have pronounced effects on epithelial cells. We have localized HGF and c-met in the placenta using both in situ hybridisation and immunohistochemistry. In addition, RT-PCR analysisof preimplantation human embryos was performed for this growth factor and its receptor. The messageand protein for HGF were detected exclusively in the villous core throughout pregnancy. Villous cytotrophoblast and decidual glands were positive for c-met. Trophoblast cells lost their expressionof c-met as they migrated off the trophoblast columns into the decidua. RT-PCR revealed that early embryos do not contain messagefor either HGF or c-met. Our resultsconclusively show that HGF expressionis confined to the villous core and therefore acts in a paracrine manner. This is likely to representan important mechanism for driving cytotrophoblast proliferation and thus placental growth.
Evidencefor Platelet-Endothelial Cell Adhesion Molecule (PECAM) Mediated Migration of Trophoblast Cells in Macaque SpiralArteries.T.N. Blankenshipand A.C. Enders, Dept. of Cell Biology and Human Anatomy, School of Medicine, Univ. of California, Davis, CA, USA. Hemochorialplacentationis characterizedby the invasionof uterine blood vessels by trophoblast cells. These cells proceedto migrate within uterine spiralarteries, opposite to the direction of normal blood flow. Observations indicate adhesionof intra-arterial trophoblast to endothelium as well as to adjacent trophoblast cells. We present evidencethat PECAM may participate in this adhesion. Macaque endometrial tissue was collectedfrom day 15 of pregnancy (implantation begins on day 9) to term. In early specimens arteries were often nearly occluded by cytokeratin labeled trophoblastcells.Adjacent sectionsrevealedthe presenceof PECAM on these trophoblast cells and the endothelium. After day 30 the invaded arteries usually contained a reformed lumen and trophoblastcellswere increasinglyevident in the modifiedwalls of arteries,where PECAM labeling was often reduced on cells distant from the lumen. Endothelium of invaded and uninvaded uterine vesselsretained PECAM reactivity throughout gestation. Because PECAM is a counter-ligand for PECAM, we concludethat this molecule is directlyinvolvedin adhesionof trophoblast cellsto arterial endothelium. Supported by NIH grant HD24491,
Identification and characterization of vascularendothelial growth factor binding proteins in the serum of pregnant women. D. Steohen Chamock-Jones,Dawn E. Clark and Stephen K. Smith. Reproductive Molecular Research Grouo. Deoartment of Ob/Gvn. Universitv of Cambridge. The kosie ‘Maternity Hospital. Cambridge. CB2 2SW. UK
Immunolocalization of tumor necrosisfactor-a (TNF-o) in the placental bed of normotensive and preeclamptic human pregnancies. R. Piinenborn”, P.J. McLaughlinb, L. Vercruysse”,M. Hanssen$, P.M. Johnsonb & F.A. Van Asschea.aDept. Obstet. Gynaec.,Univ. of Leuven, Belgium; bDept. Immunology, Univ. of Liverpool, U.K.
Vascular endothelial growth factor (VEGF) is a potent stimulator of angiogenesisboth in vivo and in vitro. We have shown that the mRNA encoding the VEGF receptor (flt) is highly expressedon the trophoblast cells (Charnock-Joneset al 1994). We have also shown that the human placenta contains mRNAs which encode soluble flt receptors. To investigate whether these soluble forms are involved in the regulation of VEGF action in the placenta we have cloned and expressed these. We have also detected and characterized VEGF binding proteins in the serum of pregnant women by ligand cross-linking, size exclusionchromatography and immunoprecipitation. The presence of these VEGF antagonists suggests that there is a complex mechanism for regulating the actions of VEGF both on endothelial cells and on trophoblast. This may be of fundamental importance in the regulation of vascular development and trophoblast function within the human placenta. D.S. Charnock-Jones, A.M Sharkey, C.A. Boocock, A. Ahmed, R. Plevin, N. Ferrara and S.K. Smith (1994). Biol Reprod 51 524-530.
Aim: To identify TN&a immunopositive cellsin human normotensive (NT) and preeclamptic(PE) placental bed. Methods: Placental bed biopsies of 12 NT and 26 PE term or near-term pregnancies,and 7 additional 1st and early 2nd trimester specimenswere immunostained with a mouse IgGl monoclonal antibody (JlD9) reactive specifically with human TN&a (1:300 ascitic fluid), using a biotin-streptavidin-peroxidasetechnique. Buffer and irrelevant IgG controls were alwaysincluded. Results: Variable staining of stromal cells was found in all specimens. Specimens of early pregnancy showed strong immunostaining of proliferating tips of anchoring villi, invasive interstitial cytotrophoblast, and endovasculartrophoblast. At term, immunostaining was found in trophoblast incorporated within spiral artery walls. In PE biopsies uninvaded spiral arteries showed very little staining, except in atherotic vessels,with often intense immunostaining of lipophages. Conclusion: Staining of extravillous cytotrophoblast is suggestive for a role in early invasion, Staining of lipophagesin PE specimensindicatesa potential role of this cytokine in the development of atherotic lesions.
R.T.C.
and T.G.W.M.S.
Canada
A.37
1996
Hepatocyte Growth Factor and its Receptor c-met: Localization and Expressionin the Human Placenta. D.E. Clark, S.K. Smith, A.M. Sharkey,and D.S. Charnock-Jones. Reproductive Molecular ResearchGroup, Department of Obstetricsand Gynaecology, University of Cambridge, Rosie Maternity Hospital, Cambridge, CB2 2SW, U.K. Hepatocyte growth factor (HGF), acting via its c-met receptor, is known to have pronounced effects on epithelial cells. We have localized HGF and c-met in the placenta using both in situ hybridisation and immunohistochemistry. In addition, RT-PCR analysisof preimplantation human embryos was performed for this growth factor and its receptor. The messageand protein for HGF were detected exclusively in the villous core throughout pregnancy. Villous cytotrophoblast and decidual glands were positive for c-met. Trophoblast cells lost their expressionof c-met as they migrated off the trophoblast columns into the decidua. RT-PCR revealed that early embryos do not contain messagefor either HGF or c-met. Our resultsconclusively show that HGF expressionis confined to the villous core and therefore acts in a paracrine manner. This is likely to representan important mechanism for driving cytotrophoblast proliferation and thus placental growth.
Evidencefor Platelet-Endothelial Cell Adhesion Molecule (PECAM) Mediated Migration of Trophoblast Cells in Macaque SpiralArteries.T.N. Blankenshipand A.C. Enders, Dept. of Cell Biology and Human Anatomy, School of Medicine, Univ. of California, Davis, CA, USA. Hemochorialplacentationis characterizedby the invasionof uterine blood vessels by trophoblast cells. These cells proceedto migrate within uterine spiralarteries, opposite to the direction of normal blood flow. Observations indicate adhesionof intra-arterial trophoblast to endothelium as well as to adjacent trophoblast cells. We present evidencethat PECAM may participate in this adhesion. Macaque endometrial tissue was collectedfrom day 15 of pregnancy (implantation begins on day 9) to term. In early specimens arteries were often nearly occluded by cytokeratin labeled trophoblastcells.Adjacent sectionsrevealedthe presenceof PECAM on these trophoblast cells and the endothelium. After day 30 the invaded arteries usually contained a reformed lumen and trophoblastcellswere increasinglyevident in the modifiedwalls of arteries,where PECAM labeling was often reduced on cells distant from the lumen. Endothelium of invaded and uninvaded uterine vesselsretained PECAM reactivity throughout gestation. Because PECAM is a counter-ligand for PECAM, we concludethat this molecule is directlyinvolvedin adhesionof trophoblast cellsto arterial endothelium. Supported by NIH grant HD24491,
Identification and characterization of vascularendothelial growth factor binding proteins in the serum of pregnant women. D. Steohen Chamock-Jones,Dawn E. Clark and Stephen K. Smith. Reproductive Molecular Research Grouo. Deoartment of Ob/Gvn. Universitv of Cambridge. The kosie ‘Maternity Hospital. Cambridge. CB2 2SW. UK
Immunolocalization of tumor necrosisfactor-a (TNF-o) in the placental bed of normotensive and preeclamptic human pregnancies. R. Piinenborn”, P.J. McLaughlinb, L. Vercruysse”,M. Hanssen$, P.M. Johnsonb & F.A. Van Asschea.aDept. Obstet. Gynaec.,Univ. of Leuven, Belgium; bDept. Immunology, Univ. of Liverpool, U.K.
Vascular endothelial growth factor (VEGF) is a potent stimulator of angiogenesisboth in vivo and in vitro. We have shown that the mRNA encoding the VEGF receptor (flt) is highly expressedon the trophoblast cells (Charnock-Joneset al 1994). We have also shown that the human placenta contains mRNAs which encode soluble flt receptors. To investigate whether these soluble forms are involved in the regulation of VEGF action in the placenta we have cloned and expressed these. We have also detected and characterized VEGF binding proteins in the serum of pregnant women by ligand cross-linking, size exclusionchromatography and immunoprecipitation. The presence of these VEGF antagonists suggests that there is a complex mechanism for regulating the actions of VEGF both on endothelial cells and on trophoblast. This may be of fundamental importance in the regulation of vascular development and trophoblast function within the human placenta. D.S. Charnock-Jones, A.M Sharkey, C.A. Boocock, A. Ahmed, R. Plevin, N. Ferrara and S.K. Smith (1994). Biol Reprod 51 524-530.
Aim: To identify TN&a immunopositive cellsin human normotensive (NT) and preeclamptic(PE) placental bed. Methods: Placental bed biopsies of 12 NT and 26 PE term or near-term pregnancies,and 7 additional 1st and early 2nd trimester specimenswere immunostained with a mouse IgGl monoclonal antibody (JlD9) reactive specifically with human TN&a (1:300 ascitic fluid), using a biotin-streptavidin-peroxidasetechnique. Buffer and irrelevant IgG controls were alwaysincluded. Results: Variable staining of stromal cells was found in all specimens. Specimens of early pregnancy showed strong immunostaining of proliferating tips of anchoring villi, invasive interstitial cytotrophoblast, and endovasculartrophoblast. At term, immunostaining was found in trophoblast incorporated within spiral artery walls. In PE biopsies uninvaded spiral arteries showed very little staining, except in atherotic vessels,with often intense immunostaining of lipophages. Conclusion: Staining of extravillous cytotrophoblast is suggestive for a role in early invasion, Staining of lipophagesin PE specimensindicatesa potential role of this cytokine in the development of atherotic lesions.