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The expression of receptors for epidermal growth factor and transferrin on human trophoblast
.Ibstracts: European Placenta Group
459
wary, amnion, chorion and decidua from both mid and term pregnancy contained the gonadotropin receptors. While the gonadotropin receptors in decidual cells and chorionic cytotrophoblasts increased, the receptors in amniotic epithelium decreased from mid to term pregnancy. In summary, these results demonstrate for the first time that mid pregnancy placenta and mid and term pregnancy fetal membranes and decidua contain hCG/LH receptors. This suggests that hCG may have previously unsuspected autocrine, paracrine and endocrine (with respect to fetal membranes) functions in the feto-placental unit. (Support NIH
HD14697.)
EXPRESSION OF C-ERB B-z PROTEIN PRODUCT IN HUMAN PLACENTAL VILLI AS COMPARED TO EGF-RECEPTOR J. Miihlhauser”, C. A. Schroetefl, P. Kaufmann” & M. Castellucci” (“Department of Anatomy, Aachen, FRG and b Department of Surgery, Maastricht, The Netherlands) The protein production of c-erb B-z oncogene is a trunca version of the EGF-R’ molecule. Because of this close relationship it was interesting to compare the expression of both in first trimester and full term placentae. A monoclonal antibody to the synthetic peptide of EGF-R and a polyclonal antibody for c-erb B-2 protein product were used by fluorescence and immunoperoxidase techniques. In first trimester placentae, in addition to a diffused stromal reaction, the protein product of c-erb B-z was localized in the cytoplasma of the villous cytotrophoblast and syncytiotrophoblast. In the villous trophoblast of full term placentae no reaction product could be visualized. In first trimester placentae, EGF-R was found to be localized along the cell membranes of the villous cytotrophoblast. The plasma membranes of the syncytiotrophoblast were only weakly stained. In full term placentae fluorescence and avidin/biotin immunoperoxidase reaction were found principally along the apical membrane of the syncytiotrophoblast, and to a lesser extent along the basal side of the syncytiotrophoblast. The majority of the mature villous cytotrophoblast stains negatively. C-erb B-2 oncogene protein product is expressed in different types of adenocarcinomas. EGF-R has been described in numerous growing tissues. In spite of the structural similarities of both proteins, in human placental villi they differ in three aspects: timing of expression, localization in the various villous tissues, and subcellular localization. ’ EGF-Receptor.
THE EXPRESSION OF RECEPTORS FOR EPIDERMAL GROWTH FACTOR AND TRANSFERRIN ON HUMAN TROPHOBLAST C.-J. Yeh”, J. Miihlhause#, B.-I. Hsi”, M. Castellucc? & P. Kaufmanr+ (” INSERM U210, Faculti de Mtdicine, 06034 Nice-Cedex, France and bDepartment of Anatomy, Aachen, FRG) Epidermal growth factor (EGF) is important in regulating the growth and replication of cells. Transferrin (Tr) which is an iron binding plasma protein is essential for the cellular proliferation. Both EGF receptor and Tr receptor were identified on trophoblast of human placenta. There are two types of trophoblast: cytotrophoblast, which is able to replicate, and syncytiotrophoblast which is formed by the fusion of the former and is terminally differentiated. We have carried out a comparative study of the expression of Tr receptors and EGF receptors on
460
Placenta (1989), Vol. IO
human syncytiotrophoblast and cytotrophoblast. Two monoclonal antibodies (Mabs) were used: (i) GB16, a Mab raised against human term syncytiotrophoblastic membrane and recognizes Tr receptors, and (ii) a commercially available Amersham Mab raised to a synthetic peptide of EGF receptor. They were studied on the first trimester and full term placental villi using immunofluorescence and avidin-biotin complex immunoperoxidase technique. In the first trimester placentae, EGF receptor was found along the cell membranes of cytotrophoblast and to a much lesser extent of the syncytiotrophoblast. In the full term placentae, the reaction products were found principally in the apical plasmalemma of the syncytiotrophoblast, to a lesser extent on the basal plasmalemma and only in very few of the cytotrophoblastic cells of the placental villi. In both first trimester and term placentae, the Tr receptor was identified only on the apical plasmalemma of syncytiotrophoblast. All the other types of cytotrophoblast, including villous cytotrophoblast and extravillous trophoblast of basal plate, chorion leave and placental bed, were negative. These results suggested that although both receptors for EGF and Tr are implicated in the cellular growth and proliferation, on human trophoblast, probably only EGF receptors are important for signalling the growth of trophoblast. The function of Tr receptor in the placenta is probably mainly for the transport of iron rather than for the trophoblast proliferation.
LOCALIZATION OF PROSTAGLANDIN SYNTHASE IN HUMAN AND OVINE PLACENTAL MEMBRANES R. A. Jacobs, J. Oosterhuis, P. Libby, V. Han &J. R. G. Challis (Lawson Research Institute, University of Western Ontario, London, Ontario, Canada) Production of prostaglandins by the utero-placental unit is fundamental to pregnancy and parturition. Prostaglandin synthase (PGHS) is a key enzyme in the conversion of arachidonic acid to prostaglandins. We used immunohistochemical techniques to locate the presence of PGHS in placenta and membranes from human tissues collected from either spontaneous labour at term (n = 4) or caesarean section at term (n = 4). In addition, placenta and membranes were collected from sheep at d45 (n= 3), d65 (n= 5), droo (n=7) and term labour (n=7, term= dr45). Tissues were fixed in Bouin’s solution for 4 h, washed with several changes of 70 per cent ethanol, embedded in paraffin and sectioned at 3 p. The avidin biotin method (vectastain) was used for staining, diaminobenzedine was used as the chromagen and cells were counterstained with haematoxylin. A polyclonal antibody (donated by S. Smith, Michigan State University) was raised in rabbits against PGHS extracted from ram seminal vesicles. Sections from ovine seminal vesicles were used as positive controls and preabsorption of the primary antibody with ovine PGHS resulted in a loss of staining in tissues. Staining appeared in the subepithelial layers of amnion in both species, but was more intense in sheep. Chorion from human and sheep exhibited in staining in trophoblastic cells and in the endothelium of blood vessels. The decidua from human patients stained intensely in both subepithelium and around blood vessels. A similar pattern was observed in the ovine endometrium, but staining was more intense when associated with blood vessels. Staining was apparent in the subepithelial cells of allantois from sheep. No staining was observed in the placenta from either species. There was no significant difference in the pattern of staining between tissues obtained from spontaneous delivery or caesarean section. In the sheep, the intensity of staining appeared to increase with advancing gestational age. In conclusion, we have demonstrated the presence of PGHS in membranes, but not placenta. PGHS is not found in epithelial cells of sheep or human membranes, but is strongly associated with subepithelial cells and blood vessels.
459
wary, amnion, chorion and decidua from both mid and term pregnancy contained the gonadotropin receptors. While the gonadotropin receptors in decidual cells and chorionic cytotrophoblasts increased, the receptors in amniotic epithelium decreased from mid to term pregnancy. In summary, these results demonstrate for the first time that mid pregnancy placenta and mid and term pregnancy fetal membranes and decidua contain hCG/LH receptors. This suggests that hCG may have previously unsuspected autocrine, paracrine and endocrine (with respect to fetal membranes) functions in the feto-placental unit. (Support NIH
HD14697.)
EXPRESSION OF C-ERB B-z PROTEIN PRODUCT IN HUMAN PLACENTAL VILLI AS COMPARED TO EGF-RECEPTOR J. Miihlhauser”, C. A. Schroetefl, P. Kaufmann” & M. Castellucci” (“Department of Anatomy, Aachen, FRG and b Department of Surgery, Maastricht, The Netherlands) The protein production of c-erb B-z oncogene is a trunca version of the EGF-R’ molecule. Because of this close relationship it was interesting to compare the expression of both in first trimester and full term placentae. A monoclonal antibody to the synthetic peptide of EGF-R and a polyclonal antibody for c-erb B-2 protein product were used by fluorescence and immunoperoxidase techniques. In first trimester placentae, in addition to a diffused stromal reaction, the protein product of c-erb B-z was localized in the cytoplasma of the villous cytotrophoblast and syncytiotrophoblast. In the villous trophoblast of full term placentae no reaction product could be visualized. In first trimester placentae, EGF-R was found to be localized along the cell membranes of the villous cytotrophoblast. The plasma membranes of the syncytiotrophoblast were only weakly stained. In full term placentae fluorescence and avidin/biotin immunoperoxidase reaction were found principally along the apical membrane of the syncytiotrophoblast, and to a lesser extent along the basal side of the syncytiotrophoblast. The majority of the mature villous cytotrophoblast stains negatively. C-erb B-2 oncogene protein product is expressed in different types of adenocarcinomas. EGF-R has been described in numerous growing tissues. In spite of the structural similarities of both proteins, in human placental villi they differ in three aspects: timing of expression, localization in the various villous tissues, and subcellular localization. ’ EGF-Receptor.
THE EXPRESSION OF RECEPTORS FOR EPIDERMAL GROWTH FACTOR AND TRANSFERRIN ON HUMAN TROPHOBLAST C.-J. Yeh”, J. Miihlhause#, B.-I. Hsi”, M. Castellucc? & P. Kaufmanr+ (” INSERM U210, Faculti de Mtdicine, 06034 Nice-Cedex, France and bDepartment of Anatomy, Aachen, FRG) Epidermal growth factor (EGF) is important in regulating the growth and replication of cells. Transferrin (Tr) which is an iron binding plasma protein is essential for the cellular proliferation. Both EGF receptor and Tr receptor were identified on trophoblast of human placenta. There are two types of trophoblast: cytotrophoblast, which is able to replicate, and syncytiotrophoblast which is formed by the fusion of the former and is terminally differentiated. We have carried out a comparative study of the expression of Tr receptors and EGF receptors on
460
Placenta (1989), Vol. IO
human syncytiotrophoblast and cytotrophoblast. Two monoclonal antibodies (Mabs) were used: (i) GB16, a Mab raised against human term syncytiotrophoblastic membrane and recognizes Tr receptors, and (ii) a commercially available Amersham Mab raised to a synthetic peptide of EGF receptor. They were studied on the first trimester and full term placental villi using immunofluorescence and avidin-biotin complex immunoperoxidase technique. In the first trimester placentae, EGF receptor was found along the cell membranes of cytotrophoblast and to a much lesser extent of the syncytiotrophoblast. In the full term placentae, the reaction products were found principally in the apical plasmalemma of the syncytiotrophoblast, to a lesser extent on the basal plasmalemma and only in very few of the cytotrophoblastic cells of the placental villi. In both first trimester and term placentae, the Tr receptor was identified only on the apical plasmalemma of syncytiotrophoblast. All the other types of cytotrophoblast, including villous cytotrophoblast and extravillous trophoblast of basal plate, chorion leave and placental bed, were negative. These results suggested that although both receptors for EGF and Tr are implicated in the cellular growth and proliferation, on human trophoblast, probably only EGF receptors are important for signalling the growth of trophoblast. The function of Tr receptor in the placenta is probably mainly for the transport of iron rather than for the trophoblast proliferation.
LOCALIZATION OF PROSTAGLANDIN SYNTHASE IN HUMAN AND OVINE PLACENTAL MEMBRANES R. A. Jacobs, J. Oosterhuis, P. Libby, V. Han &J. R. G. Challis (Lawson Research Institute, University of Western Ontario, London, Ontario, Canada) Production of prostaglandins by the utero-placental unit is fundamental to pregnancy and parturition. Prostaglandin synthase (PGHS) is a key enzyme in the conversion of arachidonic acid to prostaglandins. We used immunohistochemical techniques to locate the presence of PGHS in placenta and membranes from human tissues collected from either spontaneous labour at term (n = 4) or caesarean section at term (n = 4). In addition, placenta and membranes were collected from sheep at d45 (n= 3), d65 (n= 5), droo (n=7) and term labour (n=7, term= dr45). Tissues were fixed in Bouin’s solution for 4 h, washed with several changes of 70 per cent ethanol, embedded in paraffin and sectioned at 3 p. The avidin biotin method (vectastain) was used for staining, diaminobenzedine was used as the chromagen and cells were counterstained with haematoxylin. A polyclonal antibody (donated by S. Smith, Michigan State University) was raised in rabbits against PGHS extracted from ram seminal vesicles. Sections from ovine seminal vesicles were used as positive controls and preabsorption of the primary antibody with ovine PGHS resulted in a loss of staining in tissues. Staining appeared in the subepithelial layers of amnion in both species, but was more intense in sheep. Chorion from human and sheep exhibited in staining in trophoblastic cells and in the endothelium of blood vessels. The decidua from human patients stained intensely in both subepithelium and around blood vessels. A similar pattern was observed in the ovine endometrium, but staining was more intense when associated with blood vessels. Staining was apparent in the subepithelial cells of allantois from sheep. No staining was observed in the placenta from either species. There was no significant difference in the pattern of staining between tissues obtained from spontaneous delivery or caesarean section. In the sheep, the intensity of staining appeared to increase with advancing gestational age. In conclusion, we have demonstrated the presence of PGHS in membranes, but not placenta. PGHS is not found in epithelial cells of sheep or human membranes, but is strongly associated with subepithelial cells and blood vessels.