Biomedical subjects

G Desoye

Publications and source records attributed to G Desoye.

At least 37 records · Page 2Linked to original sources

PubMed2000

Self-regulation of the endothelin receptor system in choriocarcinoma cells.

The human trophoblast secretes endothelin-1 (ET-1) and expresses ET receptors. The present study tested whether the transformed BeWo, JAR and JEG-3 choriocarcinoma cells: (1) secrete endothelin-1 (ET-1); (2) express both ET-A and ET-B receptor subtypes; and (3) have the potential to allow for autologous regulation of ET-receptor proteins. The cells were cultured for 24/48 h with or without 10% FCS and, in experiments on receptor regulation, with ET-1 (5-20 nM and 10 microM). ET-1 secretion was measured by RIA and receptor levels by immunoblotting. All cell types secreted ET-1 albeit at different levels and sensitivity to FCS. All cell lines expressed both ET-A (JEG-3>BeWo=JAR) and ET-B (JEG-3=JAR>BeWo) receptor subtypes, which could be up- and downregulated depending on ET-1 concentration, culture time and FCS presence. It is concluded that BeWo, JAR and JEG-3 choriocarcinoma cells secrete ET-1 and express both ET-A and ET-B receptor subtypes. The receptor levels can be regulated by ET-1. This provides the molecular basis for an autocrine system with the potential of autologous regulation of yet unidentified ET-1-induced functions.

Antibody Specificity↗

PubMed2000

Differential regulation of endothelin secretion and endothelin receptor mRNA levels in JAR, JEG-3, and BeWo choriocarcinoma cell lines and in human trophoblasts, their nonmalignant counterpart.

Endothelin (ET) secretion and expression of both ET-A and ET-B receptor subtypes have been found in a number of primary cancers. The present study tested (1) whether choriocarcinoma cells and their nonmalignant counterpart, the trophoblast, secrete ET-1 and express ET-A and ET-B receptors; (2) whether ET-1 secretion and receptor mRNA levels are regulated by the same factors in nonvascular tissues as in vascular tissues; and (3) whether such regulation is similar in malignant and nonmalignant cells. All cells secreted ET-1 in similar amounts (approximately 0.8 fmol/10(6) cells per 24 h) and secretion was unaffected by culture and treatment. Whereas ET-B accounted for almost all (>98%) ET receptor transcripts in the choriocarcinoma cells, the trophoblasts expressed about 20% ET-A receptor mRNA. During control cultures, ET-B mRNA levels rose in choriocarcinoma, with the greatest relative increase (6-fold; P < 0.05 vs 0 h) in BeWo, whereas in trophoblasts, ET-A mRNA transiently changed after 24 and 48 h. Treatment with dexamethasone and glucose did not alter the mRNA levels in all cells. Insulin induced changes (P < 0.05) in ET-B mRNA levels in BeWo (+90 and +60% after 24 and 48 h, respectively) and JEG-3 (-70%), but not in JAR and trophoblast cells. We conclude that malignant transformation affects the responsiveness of the endothelin receptor system to external stimuli and that the regulation of the endothelin system differs in vascular and nonvascular tissues.

Base Sequence↗

PubMed2000

Hyperglycaemia-induced subcellular redistribution of GLUT1 glucose transporters in cultured human term placental trophoblast cells.

AIMS/HYPOTHESIS: We have recently shown that hyperglycaemia down-regulates the GLUT1 glucose transport system of term placental trophoblast. The reduction in GLUT1 protein alone was, however, not sufficient to explain the decrease in net glucose uptake, suggesting additional mechanisms. Therefore, we hypothesised that hyperglycaemia in vitro leads to a GLUT1 translocation from the trophoblast surface to intracellular sites. METHODS: This was tested in our study by determining the subcellular distribution of GLUT1 in human term placental trophoblast (n = 5 placentas) cultured for 48 h with 5 compared with 25 mmol/l D-glucose in vitro using immunogold labelling. RESULTS: Electron microscopic examination of cell profiles showed that 73% of total GLUT1 molecules reside in the trophoblast plasma membrane under basal conditions. The reduced GLUT1 expression (-20%; p < 0.05) after culture of the cells with 25 mmol/l glucose was accompanied by an internalisation of plasma membrane GLUT1, resulting in a loss of 40% (p < 0.05) in cell surface transporter labelling. Western blotting identified a characteristically broad band between 55-65 kDa, confirming the specificity of the GLUT1 antiserum. CONCLUSION/INTERPRETATION: We postulate that in addition to down-regulating human GLUT1 protein concentrations, glucose exerts its autoregulatory effect on hexose transport in term placental trophoblast by altering GLUT1 partitioning between the plasma membrane and intracellular sites in favour of the latter.

Cell Survival↗

PubMed2000

Antibody reaction patterns in first trimester placenta: implications for trophoblast isolation and purity screening.

The aim of this immunohistochemical and cytochemical study was to select specific antibodies to establish an efficient purification protocol for first trimester trophoblast and for subsequent purity screening of isolated trophoblast cells. The reactivity of antibodies to various cytokeratin filaments, glycoprotein CD9, fibroblast specific antigen (FSA), common leukocyte antigen CD45RB and macrophage antigens CD163, CD68 and CD14 were studied on cryosections of placental tissue. Among the cytokeratins tested, cytokeratin 7 was the only keratin filament type, which was not expressed in placental mesenchymal cells, but in all trophoblast subpopulations. Since anti-CD9, in addition to mesenchymal cells, also strongly labels extravillous cytotrophoblast cells, whereas the antibody to FSA only reacts with mesenchymal cells, anti-FSA is suitable as a depletion antibody for mesenchymal cells. Among the macrophage markers anti-CD163 was the most specific for Hofbauer cells. CD45RB was expressed on maternal and fetal leukocytes as well as on Hofbauer cells. Isolated first trimester placental cell preparations that have been collected from a density gradient contained up to 45 per cent non-trophoblast cells. Immunocytochemistry using antibodies to CK7, FSA, vimentin, CD45RB and CD163 demonstrated that subsequent immunodepletion with antibodies to CD45RB and FSA increased the purity of the trophoblast preparation to greater than 98 per cent. According to this study trophoblasts from first trimester placentae should be identified by cytokeratin antibodies specific for the isoform 7. Purification of isolated trophoblasts by density gradient alone does not result in a sufficient degree of purity.

Antibodies↗

PubMed2000

Fetal leptin and insulin levels only correlate inlarge-for-gestational age infants.

OBJECTIVE: To determine whether fetal leptin levels correlate with fetal weight and whether such correlation is direct or indirect via insulin or human placental lactogen (hPL), respectively. DESIGN: Cross-sectional study of offspring at term (n=175) with over-representation of large-for-gestational age (LGA; n=70) and small-for-gestational age (SGA; n=23) cases in a population of Caucasian women with no pregnancy pathology. METHODS: Fetal cord blood was collected after delivery. In several cases (n=62) paired mother-fetus blood samples were obtained. Leptin, insulin and hPL levels were measured by RIA. Anthropometric data (birth weight, body mass index, placental weight) were recorded. RESULTS AND CONCLUSIONS: Maternal insulin, hPL and leptin levels were higher than fetal concentrations. Cord blood leptin levels positively correlated with the anthropometric data with stronger correlations in female (0.54<r<0.66) than in male (0.32<r<0.39) neonates. Cord blood leptin levels did not differ between appropriate-for-gestational age (AGA; n=82) and SGA (n=23) neonates, but were higher (P<0.001) by 83% in LGA (n=70) than in AGA neonates. Among the different weight classes the correlations between fetal leptin and anthropometric data were only observed in LGAs, but not in AGAs or SGAs. Fetal, but not maternal, leptin levels strongly correlated with fetal insulin (r=0.56; P<0.001). After accounting for this close relationship insulin could no longer be used to predict birth weight (r=0.15, P=0.051). We suggest that the correlation of cord blood insulin with neonatal weight in LGAs is, in addition to insulin's direct anabolic action, indirectly mediated via leptin. It is hypothesized that fetal insulin stimulates fetal adipocyte leptin production.

Birth Weight↗

PubMed1999

Paracrine regulation of distinct trophoblast functions in vitro by placental macrophages.

In view of the accumulating evidence for paracrine mechanisms regulating trophoblast function, we tested the hypothesis that placental macrophages affect trophoblast activity in a paracrine fashion. Trophoblast was isolated from 17 term placentas (-IP). One aliquot of cells was further immunopurified (+IP) using an HLA class I antibody. This increased the proportion of trophoblast (+IP >97%; -IP approximately 70%) as identified by rigorous immunocytochemistry. Most (approximately 70%) non-trophoblast cells in -IP were macrophages. The cells were cultured for 5 days with a daily medium change. In addition, +IP cells from seven placentas were cultured with lipopolysaccharide (LPS)-stimulated or -unstimulated macrophage-conditioned media. The concentrations of lactate, trophoblast-specific hormones, human chorionic gonadotropin-beta (hCG-beta) and human placental lactogen (hPL), of several prostanoids and of endothelin-1 and angiotensin II were determined in the culture media. The accumulated amounts of substances released into the culture media, corrected for the greater proportion of trophoblast in +IP cultures, were on average two- to threefold higher (hCG-beta: 18-fold) in +IP than in -IP, with the exception of endothelin-1,2 (no change), angiotensin II (-70%) and 6-keto-prostaglandin-F1alpha (-40%). [3H]leucine incorporation into the trichloroacetic acid (TCA)-precipitable pool measured on day 5 was twofold higher in +IP than in -IP. Addition of conditioned media reverted these changes. The data demonstrate that placental macrophages in culture affect trophoblast biosynthetic activity in a paracrine fashion. We conclude that macrophages are important regulators of trophoblast activity.

Cell Communication↗

PubMed1999

Placental glucose transporter expression is regulated by glucocorticoids.

Although glucocorticoids play important roles in development and fetal programming, they are widely used for treatment of a variety of diseases during pregnancy. In various tissues, glucocorticoids down-regulate glucose transport systems; however, their effects on glucose transporters in the placenta are unknown. In the present study, the glucose carrier proteins GLUT1 and GLUT3 were localized in the trophoblast and endothelium of the human, rat, and mouse placenta. Subsequently, it was investigated whether glucocorticoids affect messenger ribonucleic acid and protein expression of these molecules by Northern and Western blotting using 1) human term placental trophoblast cells cultured in the presence or absence of 0.5, 5, and 50 micromol/L triamcinolone; 2) placentas of rats that received a single i.p. dose of 0.38 mg/kg triamcinolone; and 3) placentas of transgenic mice bearing an antisense glucocorticoid receptor gene construct. In all of these systems, both glucose transporters were significantly down-regulated (P < 0.05), with the exception of increased GLUT3 messenger ribonucleic acid and protein levels in transgenic mice. The results demonstrate that triamcinolone is a potent regulator of placental GLUT1 and GLUT3 expression involving the glucocorticoid receptor. We speculate that impaired expression of placental glucose transporters after glucocorticoid administration might contribute to the adverse side-effects, the foremost of which is a growth-retarded fetus, of this treatment during pregnancy.

Animals↗

PubMed1998

Hyperglycemia regulates the glucose-transport system of clonal choriocarcinoma cells in vitro. A potential molecular mechanism contributing to the adjunct effect of glucose in tumor therapy.

Glucose is taken up by tumor cells via sodium-independent facilitated diffusion along a concentration gradient. To examine the regulation of this process by substrate concentration, we investigated the effect of hyperglycemia on the glucose-transport system of choriocarcinoma-derived JAR and JEG-3 cells by culturing them for 24, 48 and 96 hr in medium containing either 5.5 (normoglycemia) or 25 (hyperglycemia) mM D-glucose, respectively. Immunocytochemically, choriocarcinoma cells expressed the high-affinity glucose transporter isoforms GLUT1 and GLUT3. Based on initial uptake measurements using 3-O-[14C]methyl-D-glucose, kinetic parameters were calculated as Km = 15 mM and Vmax = 95 fmol/sec per cell for JAR and Km = 9 mM and Vmax = 64 fmol/sec per cell for JEG-3 cells. In JAR cells cultured under hyperglycemic conditions, uptake rates were significantly increased at 15, 20 and 25 mM exogenous D-glucose concentrations as compared with normoglycemic conditions. This effect was due to an increase in Vmax, whereas Km remained unchanged. Using Northern blotting, GLUT1 mRNA levels were higher but GLUT3 transcripts were reduced upon hyperglycemia. Western blotting revealed elevated GLUT1 and GLUT3 expression under hyperglycemic conditions. Hyperglycemia did not significantly influence the glucose-transport system of JEG-3 cells. We conclude that sustained hyperglycemia stimulates the glucose-transport system of JAR, but not of JEG-3, choriocarcinoma cells in vitro due to changes in GLUT1 and GLUT3 expression levels. We speculate that this mechanism may contribute to the beneficial effects of induced hyperglycemia as an adjuvant in tumor therapy.

3-O-Methylglucose↗

PubMed1998

Sustained hyperglycemia in vitro down-regulates the GLUT1 glucose transport system of cultured human term placental trophoblast: a mechanism to protect fetal development?

The trophoblast of human placenta is directly exposed to the maternal circulation. It forms the main barrier to maternal-fetal glucose transport. The present study investigated the effect of sustained hyperglycemia in vitro on the glucose transport system of these cells. Trophoblasts isolated from term placentas and immunopurified were cultured for 24, 48, and 96 h in DMEM containing either 5.5 (normoglycemia) or 25 mmol/l D-glucose (hyperglycemia), respectively. Initial uptake of glucose was measured using 3-O-[14C]methyl-D-glucose. Kinetic parameters were calculated as K(M) = 73 mmol/l and Vmax = 29 fmol s(-1) per trophoblast cell. Uptake rates of cells cultured under hyperglycemic conditions did not differ at exogenous D-glucose concentrations in the physiological range (1, 5.5, 10, and 15 mmol/l), but were significantly decreased by 25% (P<0.05) at diabetes-like concentrations (20 and 25 mmol/l) as compared to normoglycemic conditions. This effect was due to a decrease in Vmax (-50%), whereas K(M) remained virtually unaffected. GLUT1 mRNA levels were lower by 50% (P<0.05; Northern blotting) and GLUT1 protein was reduced by 16% (P<0.05; Western blotting) in trophoblast cells cultured under hyperglycemic vs. normoglycemic conditions. We conclude that prolonged hyperglycemia in vitro reduces trophoblast glucose uptake at substrate concentrations corresponding to blood levels of poorly controlled diabetic gravidas. This effect is due to diminished GLUT1 mRNA and protein expression in the trophoblast.

3-O-Methylglucose↗

PubMed1998

Human trophoblast cells are permissive to the complete replicative cycle of human cytomegalovirus.

Human trophoblast cells were permissively infected by human cytomegalovirus. The kinetics of viral immediate-early, early, and late gene expression was clearly delayed compared to that in fibroblasts. Productive infection was unequivocally proven by the detection of virion particles, infectious virus in trophoblast culture supernatant, and cell-to-cell spread of cytomegalovirus from infected trophoblasts to uninfected fibroblasts. These observations indicate that infected trophoblasts may be involved in maternofetal transmission of human cytomegalovirus.

Antigens, Viral↗

PubMed1997

Mercurochrom can be used for the histochemical demonstration and microphotometric quantitation of both protein thiols and protein (mixed) disulfides.

Mercurochrom [2,7-dibromo-4-(hydroxymercuri)-fluorescein disodium salt] used for staining of protein thiols in addition binds to other groups of proteins. Experimental evidence is provided that mercurochrom bound to non-thiol groups forms a 1:1 adduct with protein (mixed) disulfides. The disulfide contents of three different types of cells determined biochemically correlated with the corresponding mean integrated optical densities determined microphotometrically after mercurochrom staining of groups other than thiols. Intracellular disulfide exchange has been studied, leading to a transformation of protein mixed disulfides to protein disulfides and an equimolar loss of protein thiols. Protein mixed disulfides were generated from protein thiols using both methyl methanethiosulfonate (MMTS) and 2,2'-dihydroxy-6,6'-dinaphthyldisulfide (DDD). Loss of thiols as well as the equimolar increase of protein mixed disulfides were followed using both mercurochrom staining for thiols and for disulfides. Generation of protein mixed disulfides due to the DDD reaction was also followed by azocoupling with Fast blue B. On the basis of the observed stoichiometry between the loss of protein thiols and the quantity, increase or conversion of protein disulfides determined microphotometrically using both mercurochrom staining and DDD Fast blue B staining, we conclude that: (1) 1 mol of mercurochrom is bound per mol of protein (mixed) disulfide; and (2) the molar absorptivity of mercurochrom bound to disulfides is epsilon 520 = 34940. This study demonstrates that mercurochrom can be used for the quantitative determination of the oxidative status of protein thiols in cells.

Animals↗

PubMed1997

Drug actions in preeclampsia: aspirin, but not magnesium chloride or dihydralazine, differentially inhibits cultured human trophoblast release of thromboxane and prostacyclin without affecting angiotensin II, endothelin-1, or leukotriene B4 secretion.

OBJECTIVE: We hypothesized that aspirin Mg++, and dihydralazine affect the release of vasoactive agents from cultured human placental trophoblast. STUDY DESIGN: Cytotrophoblasts isolated from placentas of preterm or term deliveries of 14 healthy control women and 15 preeclamptic women were cultured in Dulbecco's modified Eagle's medium for 5 days in the presence or absence of either 0.1 mmol/L aspirin, 3 mmol/L magnesium chloride, or 136 ng/ ml dihydralazine. Vasoactive substances were quantitated by radioimmunoassay with mean +/- SEM percentage of untreated cells (= 100%) compared by the Mann-Whitney U test and analysis of variance. RESULTS: Aspirin inhibited (p < 0.01) both thromboxane and prostacyclin on days 1 and 2 in culture but not on days 3 to 5 unless the Dulbecco's modified Eagle's medium was supplemented with arachidonic acid. Aspirin inhibition was greater (p < 0.01) for thromboxane in cells cultured 24 hours after preeclamptic pregnancy (preterm 29.9% +/- 6.8%, term 20.1% +/- 5.9%) compared with normal controls (preterm 66.3% +/- 10.6%, term 68.9% +/- 11.6%). Aspirin reduced (p < 0.01) the ratio of thromboxane to prostacyclin in media of cells from preeclampsia (untreated 27.8 +/- 7.2, aspirin 13.3 +/- 4.4), but aspirin had no effect on this ratio in cultures from control normal pregnancies (untreated 6.8 +/- 2.9, aspirin 4.8 +/- 1.1). Neither magnesium chloride nor dihydralazine affected trophoblast prostanoid production, and no drug altered the media levels of angiotensin II, endothelin-1, or leukotriene B4. CONCLUSION: Aspirin selectively inhibits trophoblast prostanoid production. This inhibition depends on the availability of arachidonic acid and the presence or absence of preeclampsia. Magnesium and dihydralazine effects in pregnancy are not related to altered release of trophoblast vasoactive compounds.

Angiotensin II↗

PubMed1996

Altered release of endothelin-1,2 and thromboxane B2 from trophoblastic cells in pre-eclampsia.

The aim of the study was to investigate whether pre-eclampsia is associated with an altered release of vasoactive substances from trophoblastic cells in vitro. Trophoblastic cells from 15 uncomplicated control pregnancies and 18 pre-eclamptic pregnancies at preterm (weeks 31-36; n = 12) and term (weeks 37-40; n = 21) were cultured for 5 days. The concentrations of angiotensin II (AII), endothelin-1,2 (ET-1,2), thromboxane B2 (TXB2), 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and leukotriene B4 (LTB4) were measured daily in culture media for 5 days by radioimmunoassay. In pre-eclampsia, concentrations of ET-1,2 were decreased (P < 0.01) at both preterm and term, TXB2 concentrations were increased (P < 0.05) only at preterm and the TXB2-6-keto-PGF1 alpha ratio was increased at both preterm and term (P < 0.01) as compared with the controls. Concentrations of AII, 6-keto-PGF1 alpha and LTB4 were similar to the controls. The data suggest that pre-eclampsia is associated with a decreased release of ET-1 and an increased release of TXB2 from trophoblastic cells in vitro.

6-Ketoprostaglandin F1 alpha↗

PubMed1996

Endothelin-1 stimulates the proliferation and invasion of first trimester trophoblastic cells in vitro--a possible role in the etiology of pre-eclampsia?

BACKGROUND: Endothelin-1 is a potent mitogen and stimulates cell chemokinesis, but these properties have not been investigated in the placenta. Trophoblastic cells from pre-eclamptic pregnancies have a reduced invasive potency and secrete less endothelin-1 than those from normal pregnancies. The present study tested the hypothesis that endothelin-1 affects trophoblast proliferation and invasion. METHODS: Trophoblastic cells were isolated from 37 placentae of normal human pregnancies at week 12 by dispastrypsin digestion and subsequently immunopurified to remove nontrophoblastic components. The effects of 5, 10, and 20 nmol/mL endothelin-1 on proliferation and invasion were determined after 24 and 72 hours, respectively, by fluorescence-activated pulse cytometry (FACS) analysis, by measuring DNA synthesis using two different methods and by a Matrigel invasion assay. RESULTS: All cell preparations uniformly responded to 10 nmol/mL by increased proliferation, owing to a greater proportion of cells in the S-phase of their cell cycle, and invasion. The effects were more pronounced after 24 hours than after 72 hours, by which time cell viability, as measured by the secretion of human chorionic gonadotropin (hCG-beta), had deteriorated. The nonselective receptor antagonist PD 142893 inhibited both endothelin-1 effects. CONCLUSION: Endothelin-1 is a mitogenic stimulus for first trimester trophoblastic cells in vitro. The stimulation of cellular invasion represents a novel effect of endothelin-1. We suggest the implication of endothelin-1 in proliferation and invasion of trophoblast and tumour cells and hypothesize a possible role in the etiology of pre-eclampsia.

Cell Division↗

PubMed1996

Ontogeny of glucose transport systems in the placenta and its progenitor tissues.

Glucose is the primary substrate for placental and fetal metabolism, however, it can be synthesized in the fetus from placentally transferred substrates at best in minimal amounts. Therefore, the growing glucose requirements of the fetus throughout pregnancy must be met by increases in placental transport capacity. Results reviewed here indicate that the GLUT1 isoform represents the major glucose transporter species in human, and very likely in all mammalian, placentae as well as in fetal membranes and its progenitor tissues. This isoform is abundant in all placental cell populations including those fronting to the maternal and fetal circulation independent of anatomical differences of the placentae. The developmental changes of GLUT1 mRNA are controversial but the amount of GLUT1 protein tends to increase during pregnancy until term. GLUT1 seems also to play the predominant role in glucose uptake in the oocytes and preimplantation cleavage stages of rodents. Its mRNA and protein levels increased during preimplantation development. Furthermore, GLUT1 was demonstrated in the trophectoderm of mouse blastocysts, the direct progenitor tissue of the placenta. GLUT2 is generally not detected in the chorioallantoic placenta. If present at all, GLUT3 seems to be the only candidate for complementing GLUT1 in placental glucose uptake and transport function. The absence of the insulin-sensitive GLUT4 in the placenta is in line with the current consensus of insulin-independent glucose transport. The fructose transporter GLUT5 was only detected in human spermatozoa. All data available at present underline the paramount importance of GLUT1 for glucose transfer in the developing fetoplacental unit.

Animals↗

PubMed1995

Pre-eclampsia and gestational age differently alter binding of endothelin-1 to placental and trophoblast membrane preparations.

The aim of the study was to compare the binding of endothelin-1 (ET-1) to membranes from placental tissue and trophoblast cells in normal and pre-eclamptic pregnancies. Plasma membranes from placental tissue and trophoblastic cells were prepared from 15 control and 18 pre-eclamptic pregnancies at either preterm (weeks 31-36) or term (weeks 37-40). ET-1 binding to tissue membranes was measured by a radioreceptor assay. In addition, binding of 56 nmol/l [125I]ET-1 to plasma membranes of trophoblastic cells was determined. In pre-eclampsia, placental membranes bound less (P < 0.01) ET-1 owing to fewer (P < 0.01) receptors at preterm than in the corresponding preterm controls. In contrast, binding of [125I]ET-1 to plasma membranes of trophoblast cells was higher (P < 0.01) in pre-eclampsia at both gestational stages than in the controls. Incubation of trophoblast cells with hydralazine reduced binding by 70%. We conclude that pre-eclampsia is associated with changes in the binding of ET-1 to its placental receptors. Moreover, the data suggest that pre-eclampsia affects non-trophoblast cells in the opposite manner to the trophoblast.

Adult↗

PubMed1995

Localisation of the high affinity facilitative glucose transporter protein GLUT 1 in the placenta of human, marmoset monkey (Callithrix jacchus) and rat at different developmental stages.

In the present study, the facilitative D-glucose transporter protein GLUT 1 was localised by immunohistochemistry in the placenta of human, marmoset (Callithrix jacchus) and rat at different developmental stages. A polyclonal antiserum against a 13-amino-acid peptide of the GLUT 1 carboxy terminus was used. It identified a protein of around 50 kDa molecular weight in immunoblotting of the placental tissues. GLUT 1 was located in the syncytiotrophoblast, in cytotrophoblast cells and in fetal endothelium. Similar staining patterns, except in human extravillous cytotrophoblast cells, were observed at all differentiation stages, despite differences in the internal placental architecture of the species. In the marmoset placenta, GLUT 1 was undetectable in endothelial cells of maternal vessels. In rat placentae, trophoblastic giant cells, epithelial cells of both visceral and parietal yolk sac, yolk sac vessels and the stratum spongiosum were stained. Reichert's membrane did not immunoreact. Preadsorption of the antiserum with a 13-amino-acid peptide resulted in the loss of immunoreactivity. The results suggest that GLUT 1 is a prominent isoform of glucose transporters in mammalian placentae. It is generally abundant in placental cell populations bordering on the maternal and fetal circulations and may therefore facilitate an effective glucose supply to the fetus and placenta.

Animals↗

PubMed1995

Immunohistochemical evidence of p53 protein in human placenta and choriocarcinoma cell lines.

We investigated the expression of the tumour-suppressor and cell cycle control protein p53 in human first trimester and term placenta, three choriocarcinoma cell lines (Jeg-3, JAR, BeWo) and human choriocarcinoma. Using monoclonal antibodies against p53 (DO-7, Ab-6, DO-1, PAb 1801), paraffin-embedded sections of first trimester and full-term placentae, human choriocarcinoma and Jeg-3, JAR and BeWo, as well as cytospins, were evaluated immunohistochemically. In addition, Western blots were carried out with the same antibodies on choriocarcinoma cell lines. In placentae, a small number of villous and extravillous cytotrophoblast cells, as well as very few syncytiotrophoblast cells, stained intensively. Also, p53 was visualized in some nuclei of the placental basal plate, whereas stroma and endothelium were negative for p53. Jeg-3, JAR and BeWo also showed a positive nuclear reaction with all applied antibodies. In paraffin-embedded sections of human choriocarcinoma, staining was confined to the nuclei of malignant cells. The results suggest that p53 is overexpressed not only in malignant tumour cells but in certain trophoblast cell populations of the human placenta as well.

Cell Line, Transformed↗