DNA synthesis and content in human decidual cells at different stages of differentiation based on flow cytometry data]

Flow cytometry analysis of the DNA content of human decidual cells at the physiologically normal pregnancy and in the case of toxicosis was carried out. During the normal pregnancy DNA-histogram parameters were seen to vary: the number of S-phase cells decreased, the coefficient of variation of the G1/0 peak increased. These alterations correlated positively with the increase in the share of decidual cells with properties of terminally differentiated cells. The most pronounced quantitative alterations in variability of DNA content in G1/0 cells were observed in cases of toxicosis of pregnancy. Phenomena of variability of the nuclear DNA in the terminally differentiated decidual cells is considered to be a sign of cell death through apoptosis.     

Protease cytochemistry in the murine rodent, guinea-pig and marmoset placenta

Plasma membrane and lysosomal proteases, gamma-glutamyl transferase and extracellular matrix proteases were investigated by qualitative cytochemical means in the mature placenta of mice, rats, guinea-pigs and marmosets. These studies revealed similarities, which concerned primarily the lysosomal proteases in different structures of the placenta and all proteases and gamma-glutamyl transferases in the zone of placental shedding. However, species differences predominated. They were observed especially for amino-peptidase A and M, dipeptidyl peptidase IV and gamma-glutamyl transferase in the plasma membranes and extracellular matrix of the placental barrier and decidual cells of all species and the cells of the basal zone in rats and mice. Plasma membrane and extracellular matrix proteases in other parts of the placenta, e.g. the placenta stem of guinea-pigs and basal plate, amniotic and chorionic plate of marmosets occurred only in these species. Elastase substrates hydrolysing endopeptidase I and kallikrein-, thrombin-, plasmin-, plasminogen- and cathepsin B substrates hydrolysing endopeptidase II were not observed in any of these species. A general comparison of the species revealed similarities for the mouse, rat and guinea-pig placental barrier, but not for that of marmosets. The proteases of this zone in the marmoset placenta are more similar to the human situation, but do not correspond to it completely.     

Chorioallantoic placenta formation in the rat: I. Luminal epithelial cell death and extracellular matrix modifications in the mesometrial region of implantation chambers.

On days 7 and 8 of pregnancy, mesometrial regions of rat gestation sites were examined by light microscopy and transmission electron microscopy to determine what changes occur before the chorioallantoic placenta forms in that region. By day 7, gestation sites contained a uterine lumen mesometrially and an antimesometrial extension of the uterine lumen, the implantation chamber. The implantation chamber consisted of a mesometrial chamber between the uterine lumen and the conceptus, an antimesometrial chamber that contained the conceptus, and a decidual crypt antimesometrial to the conceptus. Stromal cells that formed the walls of the implantation chamber were closely packed decidual cells, while those that surrounded the uterine lumen were loosely arranged. Late on day 7, a portion of the epithelium lining the mesometrial chamber was degenerating, but this area of initial degeneration was never adjacent to the antimesometrial chamber. By early day 8, most of the epithelial cells lining the mesometrial chamber were degenerating and were being sloughed into the chamber lumen. Although degeneration of these epithelial cells morphologically resembled necrosis, it was precisely controlled, since adjacent epithelial cells lining the uterine lumen remained healthy. The space that separated the denuded luminal surface of the mesometrial chamber from underlying decidual cells became wider and was occupied by an extracellular matrix rich in cross-banded collagen fibrils. Decidual cell processes, that earlier had penetrated the basal lamina beneath healthy epithelial cells, protruded into this matrix and penetrated the basal lamina at the luminal surface. By late day 8, large areas of denuded chamber wall were covered with decidual cell processes, little remained of the basal lamina, and cross-banded collagen fibrils were scarce in the area occupied by decidual cell processes. During the times studied, uterine tissues that formed the walls of the mesometrial chamber were not in direct contact with the conceptus. This study indicates that trophoblast does not play a direct role in epithelial degeneration, basal lamina penetration, or extracellular matrix modifications in the mesometrial region of implantation chambers where part of the chorioallantoic placenta forms, although trophoblast may be required to trigger or modulate some of the changes.     

Changes in the temporal and spatial expression of H beta 58 during formation and maturation of the chorioallantoic placenta in the Rat

Cloning and sequencing of a cDNA amplified by RNA fingerprinting at the implantation site of pregnant rats revealed 80% similarity with H beta 58, previously shown to be essential for formation of the chorioallantoic placenta in the mouse. H beta 58 mRNA was detected in the endometrium of hormonally sensitized rats stimulated to undergo decidualization and in the contralateral uterine horns lacking a decidual stimulus, indicating that uterine expression of H beta 58 mRNA did not require decidualization or the presence of a blastocyst. Immunodetection in the early postimplantation uterus (Days 6-8 of pregnancy) showed H beta 58 localized in the luminal and glandular epithelia and some stromal cells. Decidual cells at Day 6 of pregnancy expressed H beta 58, and by Day 9 of pregnancy, the protein localized throughout the maternal decidua. The temporal and spatial distribution of H beta 58 in the developing chorioallantoic placenta was assessed at Days 10, 12, and 14 of pregnancy. Immunoreactive H beta 58 localized to erythroid cells within the developing fetal vasculature of the chorioallantoic primordia at Day 10 of pregnancy. By Day 12, the fetal vasculature extended into the placental labyrinth, and the erythroid stem cells continued to strongly express H beta 58. At Day 14 of pregnancy, immunoreactivity became evident in the trophoblast giant cells and syncytiotrophoblast of the fetal placenta. As the chorioallantoic placenta matured (Day 18), H beta 58 mRNA was 3.6-fold higher in the labyrinth compared with the junctional region. Stable cell lines (HRP/LRP) isolated from the rat labyrinthine placenta expressed H beta 58 mRNA and protein. The expression pattern of H beta maternal and fetal placental tissues and its early expression in fetal erythroid stem cells during formation and maturation of the chorioallantoic placenta suggest that H beta 58 plays key roles in the regulatory networks that control hematopoietic development and placentation.     

Studies on the ontogenesis and the regulatory mechanisms of placental lactogen and insulin binding sites (receptor) in rat liver

The ontogenesis of specific binding of 125I-hPL and 125I-insulin was determined in rat liver cell membranes (10(5) X g pellets), and the regulatory mechanisms of these binding sites were also examined. There were striking differences in the mode of ontogenesis between binding sites of hPL and insulin in rats. HPL binding sites were very few in liver cell membranes from fetal and immature rats. They began to increase after puberty, and markedly increased in late pregnancy. On the other hand, insulin binding sites, which decreased in late pregnancy, were dominant in fetal liver and placenta. Consequently, the lipolytic and glycogenolytic activities of hPL in maternal liver were accentuated, whereas the effects of insulin on maternal liver were suppressed. In contrast, in fetal liver and placenta only the anabolic effects of insulin seemed conspicuous. According to the results of experiments on in vivo administration of estradiol-17 beta, progesterone, hydrocortisone or hPL to intact or hypox-rats, and the measurement of serum rat chorionic mammotropin (rCM), rPRL, estradiol-17 beta, and insulin during pregnancy in rats, the increase in hepatic hPL binding sites observed in late pregnancy might be, at least in part, due to rCM secreted from placenta, and the decrease in insulin binding sites due to the increase in serum insulin itself in rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Contact microscopic and histochemical studies of the placenta in normal and pathological pregnancy]

The placenta was studied in 70 women: 19 of them had physiological pregnancy and 51 had pregnancy complicated with late toxicosis. Lesions in the placenta have been shown to increase with the growing severity of toxicosis, and compensatory potencies--to decrease. In late toxicosis the expansion of desorganization and reparation in the placenta occurs from the center towards periphery, the peripheral parts playing the role of reserved zones of the placenta, keeping high functional activity.     

Electron microscopic study of the differentiation of decidual cells. I. The ultrastructure of large decidual cells in the antimesometrial portion of the rat decidua

The large decidual cells (LDC) of the antimesometrial part of decidua in rats of 7-9 days of gestation were studied by electron microscope. The decidual tissue has an epithelium-like pattern of organization. The apical surface of LDC is facing the pericapillar space making numerous villi. Lateral surfaces of these cells maintain close contact with each other by means of zona adhaerens, gap junctions, spot desmosomes and simple junctions. Accumulation of electron dense granules measuring from 0.05 to 0.3 mkm is seen in the apical parts of LDC. The Golgi complex and rough endoplasmic reticulum are much developed. The material of rough endoplasmic reticulum is denser than the cell matrix. Disperse chromatin is seen in the nucleus, whereas the granular component is dominanting in the nucleolus. It is concluded that the LDC may have a high metabolic activity, and that the secretion is a mode of fulfilling specific functions of LDC.     

Hyaluronate and CD44 expression patterns in the human placenta throughout pregnancy

Hyaluronan (HA) and CD44 are involved in several processes such as cell migration and differentiation. In the present study, we examined the expression and distribution of both hyaluronan and its cell surface receptor (CD44) in the human placenta, which is a rapidly growing and differentiating organ that plays a fundamental role in fetal life. Hyaluronan was detected by a specific biotinylated binding probe, termed b-PG. In the first half of gestation, HA was strongly expressed in the stroma of the mesenchymal villi which have been previously identified as responsible for the growth and differentation of the villous trees. The other villous types showed an intense staining only in the fetal vessel walls and in the connective tissue closely underlying the trophoblastic cover. In addition, hyaluronan positive staining was also apparent in a restricted rim of villous stroma directly apposed to extravillous cytotrophoblastic cell islands and cell columns. In full term placentas, all villi expressed HA in their stromal tissue with a more homogenous staining than in the first half of gestation. In contrast to hyaluronan, in the first trimester CD44 was restricted to some of the Hofbauer cells which may be able to internalize hyaluronan, thus playing a significant role in its removal in early pregnancy. CD44 was primarily expressed starting from the 16th week of gestation. At the end of pregnancy it was expressed in the various villous types, especially in stem villi. Moreover, the plasma membrane of some extravillous cytotrophoblastic cells in the basal plate and the large majority of the decidual cells showed a positive immunostaining for this receptor. Taken together, these data suggest that HA is strongly involved in early villous morphogenesis, whereas CD44 seem to be play an important role in tissue remodelling later in gestation.     

Licht- und elektronenmikroskopische Untersuchungen an der Basalplatte der reifen menschlichen Plazenta

Zusammenfassung In der Basalplatte der reifen menschlichen Plazenta lassen sich elektronenmikroskopisch verschiedene Arten von Trophoblastzellen (großer basaler (a), klarer (b), spongiotrophoblastähnlicher (c) Cytotrophoblast; Riesenzellen des Cyto- und Syncytiotrophoblasten) und verschiedene Typen von Deziduazellen (große Deziduazelle mit gut bzw. wenig differenziertem Cytoplasma, kleine Deziduazelle, undifferenzierte Stromazelle) nachweisen; ihr Feinbau wird eingehend beschrieben. Die Zellen sind in verschiedenen Schichten angeordnet und teilweise durch Fibrinoidablagerungen voneinander getrennt. Das Nitabuchsche Fibrinoid bildet jedoch keine dichte Grenze zwischen mütterlichen (Dezidua-) und fetalen (Trophoblast-) Zellen. In der Durchdringungszone liegen daher Zellen verschiedener Herkunft unmittelbar nebeneinander. — Die großen Deziduazellen weisen am Schwangerschaftsende keine strukturellen Äquivalente größerer Stoffwechselleistungen auf. Die kleinen Deziduazellen sind offenbar zu einer verstärkten Pinocytose befähigt. Einige der Deziduazelltypen dürften verschiedenen Stadien einer Entwicklungsreihe entsprechen. — Die große basale Cytotrophoblastzelle kommt aufgrund ihrer Ultrastruktur (viel rauhes ER, Golgiapparat, Sekretgranula) als möglicher Ort für die Synthese von Proteohormonen (z.B. HCG) in Frage. Ob und gegebenenfalls welche Aufgaben den anderen Trophoblastzellen der Basalplatte zukommen, kann morphologisch allein nicht entschieden werden. — Das Deziduagewebe hat eine prinzipielle Bedeutung für die spontane Lösung der Plazenta. Es werden einige morphologische Gesichtspunkte diskutiert, die für das Verständnis des Lösungsvorgangs von Bedeutung sein könnten.

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Light and electron microscopic investigations on the basal plate of the human placenta at term

Summary By means of electron microscopy different types of trophoblast cells—large basal cytotrophoblast cell, clear cell, spongiotrophoblast-like cell, giant cells deriving from the syncytio- and cytotrophoblast—and different forms of decidual cells—large decidual cell with well or poorly organized cytoplasm, small decidual cell, undifferentiated stromal cell—can be distinguished in the basal plate of the full-term human placenta. The morphological characteristics of all these cells mentioned are described. All cells of the basal plate are arranged in different layers and partially separated from each other by fibrinoid. The so-called fibrinoid of Nitabuch does not form a dense border between fetal and maternal tissue. In the junctional zone, therefore, cells of different origin are in intimate contact.—The large and poorly organized decidual cells show no signs of a higher metabolism. The small decidual cells, however, are characterized by pinocytosis. A relationship exists between the poorly and the well organized large decidual cells. This seems to be true, too, for the small decidual cells and the undifferentiated stromal cells.—The large basal cytotrophoblast cells provided with rough ER, Golgi apparatus and secretory granules are considered to be a possible site of synthesis for placental proteohormones (e.g. HCG). The other types of basal trophoblast cells mentioned above may have some special functions during pregnancy.—The decidua basalis plays a basic role in the separation of the placenta during labour. Some fine-structural aspects of the decidua which are important to the formation of the zone of placental separation are discussed.

Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Placentation in the opossum, Didelphis virginiana

For the first 9 days of gestation, opossum embryos float in uterine secretions, separated from maternal tissues by a shell membrane. Each embryo is part of the wall of its hollow embryonic sphere. By the 10th day of development, the embryo becomes enveloped by both the amnion and yolk-sac. The yolk-sac consists of vascular and non-vascular portions and, together with the surrounding trophectoderm (trophoblast), forms the yolk-sac placenta of the opossum: the allantois does not contribute to formation of the placenta. The vascular portion of the yolk-sac placenta establishes an intimate relationship with the uterine epithelium soon after loss of the shell membrane. The yolk-sac placenta is non-invasive. Cells of the trophoblast exhibit numerous microvilli, an apical endocytic complex and the lateral and basal cell membrane are elaborately folded. These features suggest a cell that is active in the transport of materials. Junctional complexes between cells of the trophoblast and uterine epithelium were not observed. The uterine epithelium changes from ciliated pseudostratified columnar with few infoldings of lateral and basal cell membranes, to non-ciliated simple columnar in which these membranes show elaborate infoldings. The cells show numerous inclusions and mitochondria are polarized to the basal half of the cell. These features suggest a cell that also is active in the transport of materials.     

Chorioallantoic placenta formation in the rat: II. Angiogenesis and maternal blood circulation in the mesometrial region of the implantation chamber prior to placenta formation.

Rat gestation sites were examined on days 7 through 9 of pregnancy by light microscopy and transmission and scanning electron microscopy to determine the extent of vascular modifications in the vicinity of the mesometrial part of the implantation chamber (mesometrial chamber). At a later time, the mesometrial chamber is, in conjunction with the uterine lumen, the site of chorioallantoic placenta formation. On day 7, in the vicinity of the mesometrial chamber, vessels derived from a subepithelial capillary plexus and venules draining the plexus were dilating. By early day 8, this network of thin-walled dilated vessels (sinusoids) was further enlarged and consisted primarily of hypertrophied endothelial cells with indistinct basal laminas. Sinusoids were frequently close to the mesometrial chamber's luminal surface which was devoid of epithelial cells but was lined by decidual cell processes and extracellular matrix. By late day 8, cytoplasmic projections of endothelial cells extended between healthy-appearing decidual cells and out onto the mesometrial chamber's luminal surface, and endothelial cells were sometimes found on the luminal surface indicating that endothelial cells were migrating. The presence of maternal blood cells in the mesometrial chamber lumen suggested that there was continuity between the chamber and blood-vessel lumens. On day 9, the mesometrial chamber was completely lined with hypertrophied endothelial cells, and sinusoid lumens were clearly continuous with the lumen of the mesometrial chamber. Mesometrial sinusoids and possibly the mesometrial chamber lumen were continuous with vessels in vicinity of the uterine lumen that were fed by mesometrial arterial vessels. Clearing of the mesometrial chamber lumen during perfusion fixation via the maternal vasculature indicated the patency of this luminal space and its confluence with mesometrial arterial vessels and sinusoids. The conceptus occupied an antimesometrial position in the implantation chamber on days 7 through 9, and it was not in direct contact with uterine tissues in the vicinity of the mesometrial chamber. These observations suggest that angiogenesis, not trophoblast invasion or decidual cell death, plays a major role in the opening of maternal vessels into the mesometrial chamber lumen before the formation of the chorioallantoic placenta.     

Immunohistochemical localization of a β-d -galactoside-binding lectin at the human maternofetal interface

Summary The 14 kD S-type lectin from human placenta may have a role in regulating the maternal immune response to fetal antigens. In this study, an immunoperoxidase technique was used to determine the distribution of the lectin at the human maternofetal interface. Tissue obtained during the first trimester of pregnancy and at term was used. The lectin was not detectable in either the villous syncytiotrophoblast or the underlying cytotrophoblast in first-trimester tissue, although some cells of the cytotrophoblast columns were reactive. It was also not detectable in villous or extravillous trophoblast populations at term. In contrast, strong reactivity was found in decidual stromal cells throughout gestation, and endometrial stromal cells were also positive. The lectin is, therefore, not a component of the immunosuppressive factors associated with syncytiotrophoblast membranes, but may have a role in either the decidual control of trophoblast migration or some functions unrelated to pregnancy, or both.     

Increase in 15-hydroxyprostaglandin dehydrogenase activity in the ovine placentome at parturition and effect of oestrogen

Type 1 NAD(+)-dependent 15-hydroxyprostaglandin dehydrogenase (PGDH) is the key enzyme for metabolism of active primary prostaglandins to inactive forms in gestational tissues. The present study examined the activity and immunolocalization of PGDH in the ovine placenta, fetal membranes and uterus over the latter half of pregnancy, and its potential regulation by oestradiol. Placenta, fetal membranes and myometrium were collected from sheep with known single insemination dates on days 70, 100 and 135 of gestation and in active labour demonstrated by electromyographic activity. In addition, chronically catheterized fetuses were infused with oestradiol (100 microgram kg(-1) per 24 h) (n = 5) or saline vehicle into the fetus from day 120 to day 125. PGDH activity measured in placental extracts remained constant from day 70 to day 135 of gestation, and then significantly (P < 0.05) increased by 300% in active labour. Immunoreactive PGDH was localized in the placentome at all stages and was present predominantly in the fetal component of the placentome in uninucleate, but not in binucleate, trophoblast cells. Similarly, in the fetal membranes PGDH immuno-reactivity was present in the uninucleate trophoblast but not in the binucleate cells of the chorion. PGDH immunostaining was also present in the endometrial luminal epithelium, in the smooth muscle of the myometrium, and the glandular epithelium of the cervix. Infusion of oestradiol into the fetal circulation from day 120 to day 125 of gestation had no effect on placental PGDH activity. Immunohistochemistry was used to localize oestrogen receptor alpha in intrauterine tissues to investigate further the failure of oestradiol to increase PGDH activity. Immunoreactive oestrogen receptor alpha was not present in the fetal component of the placenta, although it was expressed in adjacent maternal-derived cells. It is concluded that (1) PGDH activity increases in late gestation; (2) PGDH is expressed in uninucleate trophoblast cells in the ovine placenta and fetal membranes, and also in the maternal endometrial epithelium and stroma, myometrium and cervix; (3) oestrogen receptor alpha is not expressed in fetal cells in the placenta or fetal membranes; and (4) the increase in PGDH activity is not regulated by oestradiol administered to the fetus.     

Cytosolic phospholipase A(2)and 15-hydroxyprostaglandin dehydrogenase mRNA expression in murine uterine and gestational tissues during late pregnancy.

We evaluated the changes in mRNA expression of cytosolic phospholipase A(2)(cPLA(2)) and 15-hydroxyprostaglandin dehydrogenase (PGDH) in intrauterine and gestational tissues during mid-late murine pregnancy. Tissues (decidual caps, fetal membranes, and placentae, uterus, and cervix) were collected from pregnant mice at days 12, 14, 16, 18, and 19 (am and pm) of gestation. Total RNA was isolated and evaluated for cPLA(2)and PGDH expression by northern blot analysis normalized to GAPDH expression. Expression of mRNA for cPLA(2)increased in the placentae and decidual caps on day 18 and 19 pm, respectively. There was also increased expression for PGDH mRNA in the placenta and fetal membranes at the later stages of pregnancy. The tissue specific differences in expression of cPLA(2)and PGDH suggest that changes in enzymatic regulation of PG production and degradation may be crucial for the initiation of labour.     

Endocytic and transcytotic processes in villous syncytiotrophoblast: role in nutrient transport to the human fetus

The supply of nutrients to the developing fetus is a major function of the human hemochorial placenta, a placenta type in which the fetal chorion is in direct contact with the maternal blood. At term, nutrients have to be transported across two cell layers in chorionic villi, the syncytiotrophoblast (STB) and fetal endothelial cells. The STB is a continuous syncytium covering the entire surface of chorionic villi. This polarized epithelium is specialized in exchange processes and membrane trafficking between the apical membrane facing the maternal blood and the basal membrane facing the fetal endothelium. To meet placental and fetal requirements, the STB selectively takes up and transports a variety of nutrients, hormones, growth factors and cytokines and also transfers passive immunity to the fetus by receptor-mediated transcytosis. In this review in vivo and in vitro systems currently used to study STB functions are discussed and the potential mechanisms of transplacental IgG, iron, lipoprotein and glucose transport are presented. As revealed in this article, the placenta is a tissue where intensive cell biological research is required to unravel endocytic trafficking pathways in a highly specialized cell such as the STB.     

Syndecan expressions in the human amnion and chorionic plate

The syndecan family consists of four distinct membrane glycoproteins in mammals. Syndecans control cell proliferation, differentiation, adhesion and migration through participation in cell-cell interactions, anchorage of cells to the extracellular environment, and modulation of multiple growth factors. Therefore, syndecans may play a pivotal role in the regulation of cell behaviour depending on the cellular microenvironment. Here, we demonstrate that syndecan-1, syndecan-2 and syndecan-4 are expressed in fetal membrane tissue with different immunolocalizations. Syndecan-1 is expressed in the amniotic epithelium, localizing at basolateral cell surfaces. Syndecan-2 and syndecan-4, in contrast, are mostly localized in intracellular compartments, in the extravillous cytotrophoblastic cells and in some fibroblasts of the chorionic plate as well as in the amniotic epithelial cells. In the latter, syndecan-4 is mainly localized in the apical part of the cells. Our results strongly suggest a key role of syndecan-1, syndecan-2 and syndecan-4 in the determination of structural and functional characteristics of human amnion and chorionic plate. Since the solute exchanges between fetus and mother take place in fetal membranes, our data suggest that syndecans are important players in the placenta for the establishment of the fetal-maternal inter-communication.     

Blastocyst implantation in the Chinese hamster (Cricetulus griseus)

Embryonic development of the Chinese hamster (Cricetulus griseus) was studied from the onset of implantation to the formation of the parietal yolk sac placenta. Implantation began on day 6 of pregnancy, when the embryo became fixed to the uterine luminal epithelium. At this time there was no zona pellucida, and microvilli of the trophoblast and uterine epithelium were closely apposed. Stromal cells immediately adjacent to the implantation chamber began to enlarge and accumulate glycogen. By day 7 the mural trophoblast penetrated the luminal epithelium in discrete area. The trophoblast appeared to phagocytize uterine epithelial cells, although epithelium adjoining the points of penetration was normal. In other areas nascent apical protrusions from the uterine epithelium indented the surface of the trophoblast. The epiblast had enlarged and both visceral and parietal endoderm cells were present. The well-developed decidual cells were epithelioid and completely surrounded the implantation chamber. On day 8 the uterine epithelium had disappeared along the mural surface of the embryo. The embryonic cell mass was elongated and filled the yolk sac cavity. Reichert's membrane was well developed. The uterine epithelial basal lamina was largely disrupted, and the trophoblast was in direct contact with decidual cells. Primary and secondary giant trophoblast cells were present and in contact with extravasated maternal blood. The mural trophoblast formed channels in which blood cells were found in close proximity to Reichert's membrane. Decidual cells were in contact with capillary epithelium and in some cases formed part of the vessel wall. Structural changes occurring in the embryo and endometrium during implantation in the Chinese hamster are described for the first time in this report and are compared to those described for some other myomorph rodents.     

Protease cytochemistry in the murine rodent,guinea-pig and marmoset placenta

Summary Plasma membrane and lysosomal proteases, -glutamyl transferase and extracellular matrix proteases were investigated by qualitative cytochemical means in the mature placenta of mice, rats, guinea-pigs and marmosets. These studies revealed similarities, which concerned, primarily the lysosomal proteases in different structures of the placenta and all proteases and -glutamyl transferases in the zone of placental shedding. However, species differences predominated. They were observed especially for aminopeptidase A and M, dipeptidyl peptidase IV and -glutamyl transferase in the plasma membranes and extracellular matrix of the placental barrier and decidual cells of all species and the cells of the basal zone in rats and mice. Plasma membrane and extracellular matrix proteases in other parts of the placenta, e.g. the placenta stem of guinea-pigs and basel plate, amniotic and chorionic plate of marmosets occurred only in these species. Elastase substrates hydrolysing endopeptidase I and kallikrein-, thrombin-, plasmin-, plasminogen- and cathepsin B substrates hydrolysing endopeptidase II were not observed in any of these species. A general comparison of the species revealed similarities for the mouse, rat and guinea-pig placental barrier, but not for that of marmosets. The proteases of this zone in the marmoset placenta are more similar to the human situation, but do not correspond to it completely.In honour of Prof. P. van DuijnSupported by the BMFT (Project CMT 35) and Sfb 174In part presented at a Symposion on Progress in General, Applied and Diagnostic Histochemistry (Modra, Czechoslovakia on 12–15 April, 1984; abstracts published in Histochem J 17, No 5, 1985)     

Proliferin secreted by cultured cells binds to mannose 6-phosphate receptors

Proliferin is a prolactin-related glycoprotein secreted by proliferating mouse cell lines and by mouse placenta. In an attempt to identify target sites for proliferin action, we looked for proliferin receptors in murine fetal and maternal tissues during pregnancy using proliferin purified from the conditioned medium of a constructed Chinese hamster ovary cell line carrying amplified copies of proliferin cDNA. Purified proliferin bound to membrane preparations from fetal or maternal liver and from placenta with a Kd of 1 to 2 nM. The amount of proliferin bound per microgram of membrane protein varied markedly during pregnancy; maximal binding to day 16 fetal liver membranes was approximately 25 times that to liver membranes from adult animals. Binding to fetal and maternal receptors was specifically and completely inhibited by mannose 6-phosphate, with half-maximal inhibition at 10 microM. Furthermore, non-glycosylated proliferin did not inhibit the binding of the glycosylated protein. A approximately 300 Kd proliferin receptor was purified from the liver of pregnant mice using a proliferin affinity column and elution with mannose 6-phosphate. This receptor reacted with antibodies directed against the rat cation-independent mannose 6-phosphate receptor. We conclude that 1) proliferin secreted by cultured cell binds to cation-independent mannose 6-phosphate receptors and therefore may be a lysosomal protein or targeted to lysosomes, and 2) the concentration or activity of mannose 6-phosphate receptors in murine fetal and maternal liver and in placenta is regulated during pregnancy.     

Ultracytochemical localization of guanylate cyclase in early human placenta

Previous biochemical and cytochemical studies have indicated that in human term placenta the enzyme guanylate cyclase (GC) is associated mostly with the cytosolic fraction of homogenates and localized on the syncytiotrophoblast microvillous border. In the present study we have shown cytochemically the GC particulate form in early human placenta using guanylyl-imidodiphosphate [Gpp(NH)p] as substrate and NaN3 as activator. In samples of placental villi taken from the 6th to 12th week of pregnancy, the GC reaction product was always found on the apposing Langhans cytotrophoblast and syncytiotrophoblast plasma membranes. Furthermore, GC was present on cells in mitosis of the Langhans cytotrophoblast. From the 11th week GC was also visible on basal plasma membranes of Langhans cytotrophoblast and on endothelial cells of fetal capillaries. In samples of human term placenta GC was detectable on the syncytiotrophoblast microvillous border. This suggests a shift of enzyme localization during pregnancy.