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PubMed1998

Purification of galectin-3 from ovine placenta: developmentally regulated expression and immunological relevance.

Galectins, beta-galactoside-binding lectins, are extensively distributed in the animal kingdom and share some basic molecular properties. Galectin-3, a member of this family, is generally associated with differentiation, morphogenesis, and metastasis. In this study, galectin-3 was isolated from ovine placental cotyledons round the middle of the gestation period by lactose extraction followed by affinity chromatography on lactosyl-agarose, and separated from galectin-1 by size exclusion chromatography on a Superose 12 column. Under native conditions this lectin behaved as a monomer with an apparent molecular weight of approximately 29,000 and an isoelectric point of 9.0. The partial amino acid sequence of the peptides obtained by tryptic digestion of this protein followed by HPLC separation showed striking homology with other members of the galectin-3 subfamily. Furthermore, ovine placental galectin-3 exhibited specific mitogenic activity toward rat spleen mononuclear cells. Besides, this protein strongly reacted with a rabbit antiserum raised against a chicken galectin. Results obtained by Western blot analysis showed that its expression was greatly decreased in term placenta with respect to the middle of the gestation period, suggesting a regulated expression throughout development.

Amino Acid Sequence↗
PubMed2000

Activator protein-2 regulates human placental lactogen gene expression.

DNase I footprint analysis of the human placental lactogen-A (hPL-A) promoter using nuclear extracts from purified human trophoblast cells and BeWo choriocarcinoma cells revealed five protected regions within the proximal 325 bp. Two of the protected regions, FP4 (-289--267) and FP5 (-167--154), are homologous to regions on the human growth hormone (hGH) promoter that bind transcription factors AP-2 and/or NFI. Competitive gel shift assays and supershift assays indicated that FP4 forms complexes with activator protein-2 (AP-2) and nuclear factor I (NFI), while FP5 forms a complex with AP-2 alone. In transient transfection studies in human trophoblast cells, hPL promoter constructs containing point mutations in the AP-2 binding sites of FP4 and/or FP5 were 60-80% less active than plasmids containing the wild-type promoter. A mutation in the NFI binding site of FP4, however, had little effect on promoter activity in these cells. Overexpression of AP-2 in HepG2 cells co-transfected with the wild-type hPL promoter resulted in a significant increase in promoter activity. Taken together, these findings suggest a critical role for AP-2 in the regulation of hPL gene expression.

Base Sequence↗
PubMed1979

Glycosylation of human chorionic gonadotropin in mRNA-dependent cell-free extracts: post-translational processing of an asparagine-linked mannose-rich oligosaccharide.

Placental RNA has previously been shown to direct the synthesis of an asparagine-linked mannose-rich glycosylated form of the alpha subunit of human chorionic gonadotropin (hCG-alpha) in lysates derived from mouse ascites tumor cells. Glycosylation was dependent on the presence of homologous microsomal membranes, and the glycosylated protein was sequestered into the microsomal vesicles. Here we show that when Triton X-100 is added after 60 min of translation and the incubation is continued, there is a shift of this glycosylated form to new discrete lower molecular weight proteins. The formation of these new proteins was not the apparent result of proteolysis because (i) treatment of the fully glycosylated protein or the proteins formed in the presence of Triton with endoglycosidase H resulted in the formation of a single protein migrating at the same rate on sodium dodecyl sulfate gels; (ii) the migration of nonglycosylated hCG-alpha synthesized in the presence of membranes isolated from tunicamycin-pretreated ascites tumor cells was not changed upon Triton addition; and (iii) the Triton-induced change was inhibited by mannonolactone, yeast mannan, and purified mannose oligosaccharides. It was also shown that little processing of the mannose-rich glycoprotein occurred in the presence of microsomal membranes alone. However, addition of the ribosome-free supernatant fraction to the glycoprotein resulted in processing. These data suggest that processing of the oligosaccharide core is a compartmentalized process in which removal of sugar, presumably mannose, requires a transfer of the glycoprotein from the endoplasmic reticulum to another component of the secretory cascade.

Animals↗
PubMedDate not supplied

RU 486 induced suppression of placental neutrophil elastase inhibitor levels.

After administration of RU 486 to pregnant cynomolgus monkeys, placental morphology varied from normal to pathological. In all cases (n = 5) circulating and placental PAPP-A levels were markedly suppressed by 76.0 per cent and 55.5 per cent, respectively. When fetal demise occurred within 24 h prior to caesarian section, morphological changes consistent with an active inflammatory (polymorphonuclear leukocytosis) reaction was readily observed at the utero-placental interface, degrading the chorionic villi. Whereas heparin-Sepharose fractionated aqueous extracts of placentae inhibited human neutrophil (or granulocyte) elastase (HGE) activity, extracts of placenta being degraded by host phagocytic-proteolytic defense system were rich in HGE activity. This study establishes: (1) the cynomolgus monkey as a model for PAPP-A studies, (2) that haemochorially implanted placentae produce PAPP-A, a heparin-binding inhibitor of HGE, (3) that administration of progesterone receptor antagonist suppressed placental PAPP-A synthesis, and (4) disrupted protease-protease inhibitor equilibrium at the feto-maternal interface. Thus supporting a role for progesterone in placental PAPP-A production and maintenance of a placental barrier against maternal phagocytic-proteolytic defenses.

Administration, Oral↗
PubMed1984

Partial purification from human mononuclear cells and placental plasma membranes of an insulin mediator which stimulates pyruvate dehydrogenase and suppresses glucose-6-phosphatase.

A substance capable of stimulating pyruvate dehydrogenase (PDH) and suppressing glucose-6-phosphatase (G-6-Pase) in a cell-free system was prepared from insulin-treated human placental plasma membranes and peripheral blood mononuclear cells by formic acid extraction. This material was partially purified by molecular-exclusion chromatography, ion-exchange chromatography, and hydroxylapatite chromatography. This was found to stimulate pyruvate dehydrogenase and inhibit glucose-6-phosphatase in a dose-dependent manner. The amount or ability of this substance to stimulate pyruvate dehydrogenase was increased in the proportion to the concentration of insulin. The stimulation of pyruvate dehydrogenase by the factor was eliminated when sodium fluoride was presented in the assay of the activation. This result implied that the activation of pyruvate dehydrogenase was mediated by the stimulation of the phosphatase of pyruvate dehydrogenase complex. Each material isolated from insulin-treated human placental plasma membranes and mononuclear cells shared a number of important characteristics of putative second messengers of insulin action as follows: (i) heat and acid stability; (ii) a similar molecular weight; (iii) increased activity of pyruvate dehydrogenase in a insulin-dependent manner; and (iv) stimulated pyruvate dehydrogenase by the sodium fluoride-sensitive mechanism. This human putative second messenger of insulin action was eluted from the anion-exchange resin AG1-X8 at an ionic strength of 0.3-0.4 M, as well as from the hydroxylapatite column at a phosphate concentration of 0.2-0.3 M.

Adenosine Triphosphate↗
PubMed1986

Comparison of the properties of a soluble form of glucocerebrosidase from human urine with those of the membrane-associated tissue enzyme.

Human urine contains a soluble form of glucocerebrosidase, an enzyme associated with the lysosomal membrane in cells and tissues. Urinary glucocerebrosidase is identical to the enzyme extracted from tissues with respect to the following parameters: Km for natural and artificial substrates, inhibition by conduritol B-epoxide, and stimulation by taurocholate. The enzyme is greater than 90% precipitable by polyclonal anti-(placental glucocerebrosidase) antiserum. Upon isoelectric focussing of urinary glucocerebrosidase multiple peaks of activity were observed. Partial deglycosylation (removal of sialic acid, N-acetylglucosamine and galactose) of the urinary enzyme increased the isoelectric point to a value identical to that of the main form found after partial deglycosylation of the placental enzyme. Upon polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate followed by immunoblotting, the immunopurified urinary enzyme shows the same molecular mass forms as the enzyme immunopurified from brain and kidney. In placenta the apparent molecular mass is somewhat higher but upon removal of sialic acid, N-acetylglucosamine and galactose the urinary and the placental enzyme show identical molecular masses of 57 kDa. We conclude that the enzymes extracted from urine and tissue are identical and that differences in apparent molecular mass and isoelectric point are probably due to heterogeneity in the oligosaccharide moieties of the molecules.

Cell Membrane↗
PubMed1983

Patterns of 3 beta-hydroxysteroid dehydrogenase/delta 5-4isomerase activity in the rhesus monkey placenta and fetal adrenal.

3 beta-Hydroxysteroid dehydrogenase/delta 5-4isomerase activity (3 beta-HSDH) was examined in the rhesus monkey (Macaca mulatta) placenta and fetal adrenal at 135 and 155-162 days of gestation. Activity was evaluated in microsomes by the conversion of [3H]pregnenolone to [3H]progesterone. There was a 7-fold increase in enzyme activity in the whole adrenal (minus medulla) between the two stages of development. Combining data from both periods, enzyme activity was greater in the outer than in the inner region of the adrenal. No stage-dependent change in placental activity was evident. The temporal patterns in 3 beta-HSDH activity are consistent with corticoid and progesterone patterns in the circulation. Thus, the level of 3 beta-HSDH activity may be rate limiting in both the fetal adrenal and placenta. Enzyme activity was assessed in incubations which included unextracted, heat-treated, 100,000 g tissue supernatants. In both placental and adrenal incubations, competitive inhibition was noted. Ethyl ether extracts of 100,000 g tissue supernatants also inhibited 3 beta-HSDH in the respective tissues. GLC analysis of these extracts revealed the presence of putative dehydroepiandrosterone. Hormone levels and the nature of the inhibition that were observed are compatible with the conclusion that dehydroepiandrosterone can inhibit the conversion of pregnenolone to progesterone in vivo. The physiological importance of this remains to be determined.

3-Hydroxysteroid Dehydrogenases↗
PubMedDate not supplied

Immunoreactive gonadotropin-releasing hormone in porcine reproductive tissues.

Studies were aimed to identify and characterize IR-GnRH in the porcine endometrium, ovary, oviduct, and compare that with GnRH of hypothalamic and placental origin. RP-HPLC profiles revealed that all tissue extracts contained three peaks of IR-GnRH. Extraction with radioiodinated 125I-GnRH also resulted in three similar peaks, indicating these two extra peaks as an extraction artifact. Radioreceptor assay showed endometrial and ovarian ultrafiltrates displaced binding of 125I-GnRH analog to pituitary membrane. Secretion of uterine IR-GnRH was increased in ovariectomized, progesterone-treated gilts, as compared to the control. Treatment with estradiol + progesterone in ovariectomized gilts further increase uterine secretion of IR-GnRH. These results demonstrate that IR-GnRH identified in the porcine reproductive tissues possesses hydrophobicity similar to those in hypothalamus and placenta; endometrial IR-GnRH binds to pituitary GnRH receptors; and uterine secretion of IR-GnRH is modulated by ovarian steroids.

Animals↗
PubMed1985

Uterine and whole body oxygen extractions in the pregnant rabbit under chronic steady-state conditions.

Seventeen pregnant rabbits were studied under conscious, unstressed conditions after catheterization of the right ventricle (RV), a femoral artery (A), and a uterine vein (UV). Respiratory gas tensions, pH, and oxygen saturations and contents were determined serially throughout the latter half of gestation. The uterine coefficient of oxygen extraction increased with gestational age (R = 0.86) and became 60.6% +/- 0.3% during the last 4 days of pregnancy. To compare uterine perfusion with whole body perfusion in relationship to oxygen demands, the (Ao2 - UVo2/Ao2 - RVo2) ratio was computed. The ratio was greater than or equal to 1 after 20 days of gestation, which demonstrated that in regard to oxygen demands the rabbit uterus is relatively underperfused compared to the rest of the maternal organism in the last part of pregnancy. A comparison with analogous data in other species demonstrates that the pregnant rabbit, like the guinea pig, has a much lower rate of uterine blood flow than does the pregnant sheep. These interspecies differences in the perfusion rate and oxygen extraction of the pregnant uterus are related to differences in placental structure.

Animals↗
PubMed1986

Identification of a pituitary factor responsible for enhancement of plasminogen activator activity in breast tumor cells.

Sheep pituitary glands contain a protein that stimulates plasminogen activator (PA) activity 3- to 20-fold in serum-free cultures of T47D, MTW9/PL, and SC115 breast tumor cells. This protein was found to be similar to basic fibroblast growth factor (bFGF) in size, cationic nature, and affinity for heparin. Purified human placental bFGF, a homologue of human and bovine pituitary bFGF, was effective in stimulating mammary tumor cell PA at a concentration of 1 ng/ml. Antibodies to placental bFGF blocked the PA stimulatory activity of sheep pituitary extracts. Because of these properties, the active protein in sheep pituitary glands was identified as bFGF. This represents another function of bFGF, indicating that its spectrum of target cells is wider than previously thought. Because of previously established correlations between PA production in vitro and tumor growth in vivo, we suggest that bFGF may contribute to the growth of breast carcinomas in vivo. Other types of carcinomas may also be affected by bFGF.

Animals↗
PubMed1980

Guanfacine in the treatment of hypertension due to pre-eclamptic toxaemia in thirty women.

1. Thirty pregnant women aged 22-34 yr presenting with pre-eclampsia were treated with guanfacine for periods of 16-68 days. 2. Elevated blood pressure was lowered to a statistically and clinically significantly extent in the first week of treatment, falling almost to normal levels before parturition in 24 cases. Four days after delivery all the patients had normal blood pressures. 3. Oedema (localized or generalized) was not reduced to any extent by guanfacine and additional treatment was necessary in 17 cases. There was little effect on proteinuria. 4. Twenty-five patients reported side-effects attributable to the treatment (sedation in 25 cases, dryness of the mouth in 15, and feelings of dizziness in 6 cases). 5. No notable changes were observed in either foetal or maternal heart rate during the period of treatment. Of the 30 deliveries, 19 were spontaneous, 5 by vacuum extraction, and 6 were by Caesarean section because of suspected placental insufficiency. Six of the infants were 'small-for-date babies', but all developed normally later.

Adult↗
PubMed1999

Histologic distribution and biochemical properties of alpha 1-microglobulin in human placenta.

PROBLEM: The embryo is protected from immunologic rejection by the mother, possibly accomplished by immunosuppressive molecules located in the placenta. We investigated the distribution and biochemical properties in placenta of the immunosuppressive plasma protein alpha 1-microglobulin. METHOD OF STUDY: Placental alpha 1-microglobulin was investigated by immunohistochemistry and, after extraction, by electrophoresis, immunoblotting and radioimmunoassay. RESULTS: alpha 1-Microglobulin staining was observed in the intervillous fibrin and in syncytiotrophoblasts, especially at sites with syncytial injury. Strongly stained single cells in the intervillous spaces and variably stained intravillous histiocytes were noted. Solubilization of the placenta-matrix fraction and placenta membrane fraction released predominantly the free form of alpha 1-microglobulin, but, additionally, an apparently truncated form from the placenta-membrane fraction. The soluble fraction of placenta contained two novel alpha 1-microglobulin complexes. CONCLUSIONS: The biochemical analysis indicates the presence in placenta of alpha 1-microglobulin forms not found in blood. The histochemical analysis supports the possibility that alpha 1-microglobulin may function as a local immunoregulator in the placenta.

Electrophoresis, Polyacrylamide Gel↗
PubMed1999

Expression of the placental cytokines tumor necrosis factor alpha, interleukin 1beta, and interleukin 10 is increased in preeclampsia.

OBJECTIVE: We sought to determine whether placental cytokine expression is altered in patients with preeclampsia. STUDY DESIGN: Whole placental tissue was collected at cesarean delivery, and total ribonucleic acid was extracted. Reverse transcriptase-polymerase chain reaction was performed to determine cytokine expression. Product bands were quantitated by scanning densitometry, and results were expressed as a ratio of cytokine/housekeeping gene (cytokine expression index). Statistical analysis was performed by the Student t test and the Mann-Whitney U test. RESULTS: Placentas from 6 patients with preeclampsia and 4 normotensive patients were analyzed. Placental expression of interleukin 1beta and interleukin 10 was greater in preeclamptic women than in normotensive subjects (median interleukin 1beta cytokine expression index, 0.675; range, 0.394-0. 953; vs 0.106; range, 0.084-0.166; P =.011; median interleukin 10 cytokine expression index, 1.042; range, 0.672-1.192; vs 0.126; range, 0.062-0.398; P <.011). Tumor necrosis factor alpha messenger ribonucleic acid was detected in placentas of preeclamptic subjects but not in normotensive control subjects. CONCLUSION: Placentas from preeclamptic patients demonstrated increased expression of interleukin 1beta, interleukin 10, and tumor necrosis factor alpha. This may be in association with placental hypoxia and may contribute to the global endothelial dysfunction observed in preeclampsia.

Adult↗
PubMed2001

Quantitative digital analysis of regional placental perfusion using power Doppler in placental abruption.

PURPOSE: To apply digital imaging techniques to the quantification of placental vascularity using power Doppler. MATERIALS AND METHODS: Regional placental blood flow was measured in a case of large placental abruption, shortly after presentation and 1 week later. Images were stored digitally and analysed using purpose-designed software (CQ Analysis) to extract and measure vascular energy information. The integrated color energy (ICE) was determined in the main body of placental tissue and in a cotyledon isolated by the retroplacental clot. RESULTS: Initial assessment at 25 weeks showed only a small difference in integrated energy between normal placenta and the isolated cotyledon (ICE ratio 1.44, P < 0.04). One week later, perfusion in the isolated cotyledon had fallen both on qualitative and quantitative assessment (ICE ratio 3.98, P < 0.0001). This area subsequently became devascularized. CONCLUSION: Placental perfusion may be quantified using digital power Doppler analysis. Further studies are indicated to evaluate its role in assessing regional and/or global placental perfusion as well as fetal organ perfusion.

Abruptio Placentae↗
PubMed1995

Characterization of proteins in detergent-resistant membrane complexes from Madin-Darby canine kidney epithelial cells.

We previously isolated detergent-resistant membrane complexes (DRMs) that were not solubilized after extraction of Madin-Darby canine kidney cells with Triton X-100 on ice. The complexes were rich in glycosphingolipids, cholesterol, and glycosylphosphatidylinositol (GPI)-anchored proteins. In this study, we examined the protein composition of DRMs and further characterized the detergent solubility of these structures. Eight to ten cell-surface proteins, including proteins from both apical and basolateral membranes, were recovered in DRMs. Most DRM proteins, however, were not exposed to the surface of whole cells, and we did not detect the complex of cell-surface proteins described by Sargiacomo et al. in a similar study [Sargiacomo, M., et al. (1993) J. Cell Biol. 122, 789-807]. Almost all proteins in DRMs were solubilized by Triton X-100 at temperatures above 30 degrees C or by octyl glucoside on ice. In contrast, a GPI-anchored protein, placental alkaline phosphatase, was mostly solubilized by Triton X-100 after extraction at 10 degrees C. This protein was insoluble in ice-cold Triton X-100 when first delivered to the plasma membrane and remained so for at least 6 h after synthesis. A fraction of the lipids in DRMs remained insoluble after extraction with Triton X-100 at 37 degrees C. DRM lipids were not solubilized by octyl glucoside, suggesting that this detergent selectively extracts proteins from DRMs.

Animals↗
PubMed1989

Placental keratinocyte growth factor: partial purification and comparison with epidermal growth factor.

A water-soluble extract of term human placenta, which was previously shown to promote proliferative growth of human keratinocytes in defined medium, enhanced both cellular attachment and proliferative growth. We have partially purified the activity which enhanced cell growth and examined its action in keratinocytes. Activity was precipitated from the crude extract by (NH4)2SO4 between 33 and 60% saturation and chromatographed by gel filtration. The activity did not bind to heparin-Sepharose at low ionic strength but was adsorbed to DEAE-cellulose from which it was eluted with NaCl and then passed over phenyl-HPLC to remove bovine serum albumin previously added to protect the activity. The active fraction was applied to gel exclusion HPLC in the presence of 0.02% octyl-beta-D-glucopyranoside, which yielded an apparent Mr 35,000 for the factor. Purification was approximately 200-fold with approximately 4% recovery. The factor appears to be a protein, since activity is destroyed by trypsin. Autoradiography of cultures treated with the placental factor or epidermal growth factor (EGF) revealed that approximately 50% of cells were labeled after treatment with either growth factor compared to 9% in control cultures after a [3H]thymidine pulse. Protein synthesis was increased by about 50% 42 h after treatment with either agent, consistent with a 50% increase in nuclear labeling. Cell number was increased fivefold after 6 days in the presence of the partially purified factor, whereas EGF increased cell number eightfold. Stimulation of [3H]thymidine incorporation by the partially purified factor, in contrast, was about twice that produced by EGF, indicating that thymidine incorporation is preferentially stimulated by the placental factor and does not correlate well with other parameters of proliferative growth. The placental keratinocyte growth factor is a unique factor with a novel effect on incorporation of thymidine into DNA.

Cell Division↗
PubMed2002

Global analysis of differentially expressed genes in early gestational decidua and chorionic villi using a 9600 human cDNA microarray.

The global gene expression profiles of the decidua and chorionic villi of early human pregnancies were analysed by using cDNA microarray technology. Decidual and villous placental tissues were obtained from first trimester abortus and mRNA was extracted for cDNA microarray analysis. The human cDNA microarray [9600 clones, including known regulatory genes and expressed sequence tags (EST)] with colorimetric detection was used to identify differentially expressed genes between early gestational decidua and villi. According to cDNA microarray analysis, we have identified 641 genes with highly expressed mRNA in both decidua and villi, 49 genes with higher expressions in decidua, and 75 genes with higher expression in chorionic villi. These differentially expressed genes were further grouped into categories by their putative functions, including: cell growth-related factors, hormones/cytokines, cell adhesion molecules, signal transduction molecules, apoptosis-related factors, cytoskeleton/extracellular matrix proteins, and EST. Immunohistochemical stainings of cathepsin L, leukaemia inhibitory factor-receptor, and proliferative cell nuclear antigen showed results consistent with the microarray data. Identification of the differentially expressed genes between decidua and villi by microarray provide a global profiling of the gene expression pattern. This work adds to our understanding of placentation by reporting the gene expression profiles during first trimester human pregnancies using cDNA microarray.

Adult↗