Marker genes of decidualization: activation of the decidual prolactin gene.
(1/1114)
Decidualization of human endometrial stromal (ES) cells in vitro is induced by cAMP analogues and ligands that elevate cellular cAMP levels in a manner resembling the gonadotrophins, prostaglandin E2 and relaxin (RLX). This differentiation process is marked by the onset of decidual prolactin (PRL) production in the late luteal phase of the cycle. Using transfection assays and a primary ES cell culture system, we have demonstrated that decidual PRL gene transcription is driven by an alternative upstream promoter (dPRL), approximately 6 kb upstream of the pituitary transcription start site. In primary cell cultures, RLX not only acutely but also permanently elevated cellular cAMP levels and induced PRL secretion after 6 days. Northern and Western blot analyses revealed all regulatory subunit isoforms (RIalpha, RIbeta, RIIalpha, RIIbeta) and catalytic subunits Calpha and Cbeta of protein kinase A (PKA) in ES cells. Transcript levels of PKA subunit isoforms are not altered during decidualization, but in decidualized ES cells exposed to elevated cellular cAMP levels by stimulation with RLX for >6 days, RIalpha protein levels were significantly reduced, whereas levels of all other forms remained unchanged. Reducing the availability of R subunits changed the R:C subunit ratio in favour of C and increased kinase activity. In transient transfections of undifferentiated ES cells, the dPRL promoter was activated by 8-Br-cAMP and by C subunit (Cbeta) of PKA. This induction, and the differentiation-dependent activity of the dPRL promoter in transfected decidualized cells, was effectively abolished by the co-expression of protein kinase inhibitor (PKI). A fragment of 332 bp of 5'-flanking region of the dPRL transcription start site was sufficient to mediate full inducibility by cAMP. cAMP activation of the dPRL promoter in ES cells was biphasic as an initial weak induction within 12 hours was followed by a subsequent, much more intense induction after 12 hours. The secondary induction was not seen with a control construct driven by a consensus cAMP response element (CRE) linked to a minimal promoter. The early response of the dPRL promoter depended upon a non-palindromic CRE at position -12 and mutation of this sequence led to omission of the early, but not of the delayed, induction. The major activation of the dPRL promoter depended upon a different region between position -332 and -270 since its deletion significantly reduced inducibility by cAMP. Its action was probably indirect as its kinetics differed from classic CRE-mediated responses, and it was specific to ES cells. (+info)
Ryk is expressed in a differentiation-specific manner in epithelial tissues and is strongly induced in decidualizing uterine stroma.
(2/1114)
Ryk is a ubiquitously expressed tyrosine kinase-like receptor of unknown activity and associations. We examined ryk expression in adult mouse epithelial tissues and during embryonic development at the histological level. Ryk RNA is present at greatly increased levels in cells at particular stages of epithelial differentiation: the basal layer of skin and tongue epithelia, the intervillous layer and some crypt bases of the intestine and the lower matrix region of the hair follicle. Although ryk RNA is expressed at similar levels in a variety of tissues from embryonic day 10.5 to 18.5, specific induction of ryk RNA can be seen by in situ hybridization in the basal layer of skin and hair follicle at day 15.5-16.5, and protein staining localizes to the hair follicle by immunohistochemistry. At day 4.5 and 6.5, little if any ryk is present in the blastocyst, but it is transiently induced at a high level in mature decidual cells of the uterine stroma. We review a number of independent isolations of ryk, including fruit fly and nematode members of the ryk family. Because ryk is induced in epithelial cells seeking a final place in a differentiated tissue, or during remodeling of the endometrium, and a homologous gene, derailed, is known to regulate muscle and nerve target seeking in Drosophila, ryk may also be involved in cellular recognition of appropriate context. (+info)
Cytosolic phospholipase A2 in rat decidual cells: evidence for its role in decidualization.
(3/1114)
We investigated the existence and possible role of cytosolic phospholipase A2 (cPLA2) in rat decidualized uteri. PLA2 activity in the cytosol of a decidualized uterine horn, induced by intraluminal oil infusion, was significantly higher than that in contralateral intact horn. The activity was almost completely depressed by cPLA2 inhibitors including arachidonyl trifluoromethyl ketone (ATK). The immunoreactive signals for cPLA2 were intense in decidua and glandular epithelial cells. In vivo administration of ATK (0.1-100 microg) caused a dose-dependent inhibition of decidualization. These results show the presence of cPLA2 and its probable implication in decidualization in rat uterus. (+info)
Prostaglandin endoperoxide H synthase mRNA expression in the human amnion and decidua during pregnancy and in the amnion at preterm labour.
(4/1114)
We have examined the expression of prostaglandin endoperoxide H synthase (PGHS) isoenzymes in the amnion and the decidua during gestation, and the abundance of PGHS mRNA in the amnion at idiopathic preterm labour. PGHS-1 and -2 mRNA abundance in the amnion, determined with ribonuclease protection assays, was significantly (P< 0.05) higher at term than earlier during pregnancy. In contrast, neither PGHS-1 and -2 mRNA values, nor PGHS-specific activity, measured with a cell-free assay, was different in the decidua at term as compared to earlier gestational ages. In individual term patients, PGHS-2 mRNA values in the amnion were positively correlated with PGHS-2 mRNA values in the chorion laeve. PGHS-1 and -2 mRNA abundance was higher (P < 0.05) in the amnion after idiopathic preterm labour than in the absence of labour at the same gestational age (28-35 weeks). Thus, PGHS-1 and -2 are induced in the amnion at term. Furthermore, amniotic PGHS-2 changes in co-ordination with PGHS-2 concentrations in the chorion laeve. PGHS is not induced in the decidua at term. Increased amniotic PGHS expression may contribute to the enhanced intrauterine prostaglandin synthesis before term labour. Both PGHS isoenzymes may participate in the increase of PGHS activity in the amnion at preterm birth. (+info)
Gestational regulation of granulocyte-colony stimulating factor receptor expression in the human placenta.
(5/1114)
A number of cytokines and their receptors are abundantly expressed at the materno-fetal interface and are thought to have a function in the regulation of placentation. Granulocyte-colony stimulating factor (G-CSF) is expressed by stromal cells in both placental tissue and maternal decidua throughout placentation. In this study, we examined the expression of placental G-CSF receptor (G-CSFR) mRNA and protein throughout gestation by ribonuclease protection assays, Western blotting, and immunohistochemistry. The major placental form of G-CSFR mRNA, corresponding to a membrane-bound form of the protein, was present in first-trimester placental tissues; levels decreased in second- and were highest in third-trimester placental tissues. Two placental G-CSFR molecules, 120 kDa and 150 kDa, were detected in first- and third-, but not second-, trimester tissues. The level of the 150-kDa G-CSFR was greater in the third- than in first-trimester samples. These differences were irrespective of whether or not the patients had received prostaglandin E1 analogues, prostaglandin E1 analogues and oxytocin, oxytocin alone, or mifepristone before labor. We demonstrated by immunohistochemistry that interstitial cytotrophoblast in first- and second-trimester decidual tissue and cytotrophoblast in term fetal membranes express G-CSFR. These data demonstrate that the expression of specific forms of placental G-CSFR is strictly cell type- and developmental stage-specific, and they suggest that G-CSFR may be important in decidual invasion of cytotrophoblast and in trophoblast function during placentation. (+info)
Spatiotemporal expression of cyclooxygenase 1 and cyclooxygenase 2 during delayed implantation and the periimplantation period in the Western spotted skunk.
(6/1114)
Embryonic development in the western spotted skunk is arrested after blastocyst formation for about 200 days. This developmental arrest is believed to be due to insufficiency of uterine conditions to support continuous development. Implantation and decidualization are defective in cyclooxygenase 2 (Cox2)-, but not Cox1-, deficient mice. We therefore used Northern and in situ hybridization to investigate changes in uterine expression of Cox1 and Cox2 genes during various stages of pregnancy in the spotted skunk. Cox1 was constitutively expressed at all stages of pregnancy examined, but it did exhibit localized up-regulation in the trophoblast and necks of uterine glands at early implantation sites. Cox2 expression was highly regulated with little or no expression during delayed implantation. Cox2 expression was first detected in the uterus and trophoblast prior to blastocyst attachment and remained detectable for 5-6 days after blastocyst attachment. Cox2 expression was also localized in the luminal and glandular epithelia of uterine segments located between implantation chambers. Changes in Cox expression were not correlated with the abrupt increase in uterine weight that occurs simultaneously with renewed embryonic development but was correlated with an influx of serum proteins into the uterus observed in a previous study. (+info)
Localization of ubiquitin and ubiquitin cross-reactive protein in human and baboon endometrium and decidua during the menstrual cycle and early pregnancy.
(7/1114)
We have examined the distribution of ubiquitin and the related ubiquitin cross-reactive protein (UCRP) in paraffin-embedded sections of human and baboon endometrium and decidua by immunoperoxidase or immunofluorescence cytochemistry with antibodies raised against ubiquitin, UCRP, CD45, and insulin-like growth factor-binding protein-1. Anti-ubiquitin immunoreactivity was present in the nonpregnant endometrium, particularly in the glandular epithelial cells, and up-regulated in endometrial stromal cells as they decidualized at the beginning of pregnancy. Anti-UCRP immunoreactivity was absent from nonpregnant tissue but accumulated to high levels in decidual cells during pregnancy. Western blotting indicated that immunoreactivity was primarily due to the presence of ubiquitin and UCRP conjugated to other proteins, and that although levels of ubiquitin-protein conjugates do not change substantially during pregnancy, decidualization is accompanied by the appearance of conjugates of UCRP. Baboon uterine tissues demonstrated a similar distribution of the two proteins, which indicates that the baboon may be a useful model for study of the role of the ubiquitin system and UCRP in the establishment of pregnancy in humans. (+info)
Tissue plasminogen activator and its receptor in the human amnion, chorion, and decidua at preterm and term.
(8/1114)
The plasminogen activator system consists of two proteins: tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA), which act upon their specific receptors to generate plasmin from plasminogen located on the cell surface. Plasmin then acts directly and indirectly to degrade the components of the extracellular matrix (ECM). This process is likely to be important in the normal turnover of the ECM of fetal membranes and in its premature weakening in preterm premature rupture of the fetal membranes. Quantitative Northern analysis and in situ hybridization have shown that the decidua expresses mRNA for tPA. However, the immunolocalized tPA protein was most strongly associated with the amnion and chorion, as was its receptor annexin II, suggesting that the amnion and chorion are the targets for decidual tPA. At term, decidual tPA expression was unaffected by labor, and the tPA receptor was elevated both before and after labor. At preterm, the converse was found: decidual tPA expression was significantly (p < 0. 05) up-regulated by labor, but the tPA receptor was not. The results suggest that the generation of plasmin at term would be controlled by an increased concentration of the tPA receptor in the amnion and chorion, whereas at preterm a pathological increase in plasmin would be generated by an overexpression of tPA, initiated by labor. (+info)