Functional compensation for adipose differentiation-related protein (ADFP) by Tip47 in an ADFP null embryonic cell line

Ectopic accumulation of lipid droplets in non-adipose tissues correlates with the degree of insulin resistance in these tissues. Emerging evidence indicates that lipid droplets are specialized organelles that participate in lipid metabolism and intracellular trafficking. These properties are thought to derive from the lipid droplet-associated PAT protein family (perilipin, ADFP, and Tip47). The functions of the ubiquitously distributed adipose differentiation-related protein (ADFP) and Tip47 remain unknown. To evaluate the roles of ADFP and Tip47 in lipid biogenesis and metabolism, ADFP null and wild type (wt) clonal cell lines were established from ADFP null and wt mice, respectively. In ADFP null cells, Tip47 was identified as the sole lipid droplet-associated protein from the PAT family by mass spectroscopy, which was further confirmed by immunoblotting and immunocytochemistry. Following incubation with oleic acid, ADFP null cells were able to form lipid droplets to the same extent as wt cells. No statistical differences between the two cell types were observed in NEFA uptake or lipolysis. Small interference RNAs (siRNAs) against Tip47 were found to down-regulate protein levels for Tip47 by 85%. ADFP null cells treated with Tip47 siRNA retained the ability to form lipid droplets but to a lesser extent and shunted the utilization of exogenously added NEFA from triglycerides to phospholipids. These data support the hypothesis that Tip47 plays an important role in lipid metabolism. Tip47 and ADFP in peripheral tissues may play a critical role in regulating the formation and turnover, and hence metabolic consequences, of ectopic fat.

Syncytin is involved in breast cancer-endothelial cell fusions

Cancer cells can fuse spontaneously with normal host cells, including endothelial cells, and such fusions may strongly modulate the biological behaviour of tumors. However, the underlying mechanisms are unknown. We now show that human breast cancer cell lines and 63 out of 165 (38%) breast cancer specimens express syncytin, an endogenous retroviral envelope protein, previously implicated in fusions between placental trophoblast cells. Additionally, endothelial and cancer cells are shown to express ASCT-2, a receptor for syncytin. Syncytin antisense treatment decreases syncytin expression and inhibits fusions between breast cancer cells and endothelial cells. Moreover, a syncytin inhibitory peptide also inhibits fusions between cancer and endothelial cells. These results are the first to show that syncytin is expressed by human cancer cells and is involved in cancer-endothelial cell fusions.

Differential effect of IFN-tau on proliferation and distribution of lymphocyte subsets in one-way mixed lymphocyte reaction in cows and heifers

IFN-tau is a signaling protein secreted by the bovine conceptus during the peri-implantation period and responsible for pregnancy recognition. Its main role is the prevention of pulsatile release of luteolytic PGF2alpha, but it also exerts immunomodulatory activities characteristic for other type I interferons. The aim of the study was to examine the effect of IFN-tau on the proliferation and distribution of peripheral blood lymphocyte subsets during one-way mixed lymphocyte reaction (MLR) in cows and heifers. IFN-tau inhibited the proliferative response of lymphocytes in MLR both in cows and heifers in a dose-dependent manner, but cow lymphocytes were less susceptible than those ones from heifers. It was also showed that IFN-tau differentially changed lymphocyte subsets distribution in MLR in cows and heifers. In cows, the relative percentage of CD8(+) cells after MRL in the presence of IFN-tau was significantly lower than in heifers. Differential effect of rIFN-tau on proliferation and lymphocyte subsets distribution in a one-way MRL in cows and heifers indicated that the age of the mother is an important factor in immunomodulatory effect towards developing bovine embryo.

Oligosaccharides modulate the apoptotic activity of glycodelin

GlycodelinA (GdA), a multifunctional glycoprotein secreted at high concentrations by the uterine endometrium during the early phases of pregnancy, carries glycan chains on asparagines at positions N28 and N63. GdA purified from amniotic fluid is known to be a suppressor of T-cell proliferation, an inducer of T-cell apoptosis, and an inhibitor of sperm-zona binding in contrast to its glycoform, glycodelinS (GdS), which is secreted by the seminal vesicles into the seminal plasma. The oligosaccharide chains of GdA terminate in sialic acid residues, whereas those of GdS are not sialylated but are heavily fucosylated. Our previous work has shown that the apoptogenic activity of GdA resides in the protein backbone, and we have also demonstrated the importance of sialylation for the manifestation of GdA-induced apoptosis. Recombinant glycodelin (Gd) expressed in the Sf21 insect cell line yielded an apoptotically active Gd; however, the same gene expressed in the insect cell line Tni produced apoptotically inactive Gd, as observed with the gene expressed in the Chinese hamster ovary (CHO) cell line and earlier in Pichia pastoris. Glycan analysis of the Tni and Sf21 cell line-expressed Gd proteins reveals differences in their glycan structures, which modulate the manifestation of apoptogenic activity of Gd. Through apoptotic assays carried out with the wild-type (WT) and glycosylation mutants of Gd expressed in Sf21 and Tni cells before and after mannosidase digestion, we conclude that the accessibility to the apoptogenic region of Gd is influenced by the size of the glycans.

Progesterone and interferon-tau regulate cystatin C in the endometrium

Cystatin C (CST3) is a secreted inhibitor of lysosomal cysteine proteases cathepsins B (CTSB) and CTSL, which are abundant in the ovine endometrium and conceptus. In mice, cathepsins and cystatins play important roles in implantation and placentation. This study determined effects of the estrous cycle, pregnancy, progesterone (P4), and interferon-tau (IFNT) on CST3 in the ovine uterus. In cyclic ewes, CST3 mRNA was low on d 10, increased about 12-fold by d 12, and declined thereafter. In early pregnant ewes, CST3 mRNA was low on d 10 and increased about 130-fold from d 10 to d 20. CST3 mRNA and protein were abundant in the endometrial luminal epithelium (LE) and glandular epithelium and also in conceptus trophectoderm. In uterine flushes from pregnant ewes, CST3 protein was not detected on d 10 but was abundant on d 12, 14, and 16. In another study, treatment of ovariectomized, cyclic ewes with P4 induced a 14-fold increase in endometrial CST3 mRNA, and IFNT stimulated an additional 2-fold increase in CST3 mRNA in P4-treated ewes but not in ewes treated with P4 and the antiprogestin ZK 136,317. CST3 mRNA and protein were abundant in the endometrial luminal epithelium and superficial glandular epithelium of P4-treated ewes but were very low or not detectable in endometria of P4- and ZK-treated ewes. These results indicate that CST3 is a novel P4-induced and IFNT-stimulated gene expressed only in the epithelial cells of the ovine endometrium and implicate CST3 in regulation of uterine cathepsin activity during conceptus implantation.

Roles of glycodelin in modulating sperm function

Glycodelin is a glycoprotein with three well-defined isoforms. They are named as glycodelin-S, glycodelin-A and glycodelin-F. The three isoforms have similar protein core but different carbohydrate moieties. Glycodelin-S is abundant in the human seminal plasma. It suppresses sperm capacitation and in doing so, it maintains the spermatozoa in an uncapacitated state before they enter into the uterine cavity. Glycodelin-A is abundant in the amniotic fluid. It is also secreted from endometrial glands into uterine fluid and is produced by the fallopian tube. Glycodelin-A is the first endogenous glycoprotein that was found to inhibit the binding of spermatozoa to the zona pellucida. The immunosuppressive properties of glycodelin-A suggest that the molecule may protect the spermatozoa from immune attack in the maternal reproductive tract. Glycodelin-F was first found in the follicular fluid, hence its name. It also inhibits spermatozoa-zona pellucida binding. In addition, glycodelin-F suppresses progesterone-induced acrosome reaction, and may serve to prevent premature acrosome reaction. Preliminary findings suggest possible presence of yet another glycodelin isoform in the extracellular matrix of cumulus oophorus. Unlike glycodelin-A and -F, it stimulates spermatozoa-zona pellucida binding. In summary, different isoforms of glycodelin have different biological roles on sperm function, and they act in succession to contribute to the success of fertilization.

Placental growth factor mediates mesenchymal cell development, cartilage turnover, and bone remodeling during fracture repair

Current therapies for delayed- or nonunion bone fractures are still largely ineffective. Previous studies indicated that the VEGF homolog placental growth factor (PlGF) has a more significant role in disease than in health. Therefore we investigated the role of PlGF in a model of semi-stabilized bone fracture healing. Fracture repair in mice lacking PlGF was impaired and characterized by a massive accumulation of cartilage in the callus, reminiscent of delayed- or nonunion fractures. PlGF was required for the early recruitment of inflammatory cells and the vascularization of the fracture wound. Interestingly, however, PlGF also played a role in the subsequent stages of the repair process. Indeed in vivo and in vitro findings indicated that PlGF induced the proliferation and osteogenic differentiation of mesenchymal progenitors and stimulated cartilage turnover by particular MMPs. Later in the process, PlGF was required for the remodeling of the newly formed bone by stimulating osteoclast differentiation. As PlGF expression was increased throughout the process of bone repair and all the important cell types involved expressed its receptor VEGFR-1, the present data suggest that PlGF is required for mediating and coordinating the key aspects of fracture repair. Therefore PlGF may potentially offer therapeutic advantages for fracture repair.

Methods for studying interferon tau stimulated genes

Interferon (IFN)tau, a Type I IFN produced by the conceptus trophectoderm, is the pregnancy recognition signal in ruminants that prevents development of the endometrial luteolytic mechanism. In addition, IFNtau acts in a paracrine manner on the ovine endometrium to induce or increase expression of type I IFN-stimulated genes (ISGs). Initially, endometrial explants were cultured with native IFNtau, and the secreted radiolabeled proteins that responded to IFNtau were identified by two-dimensional polyacrylamide gel electrophoresis and fluorography. Next, the ontogeny of putative ISGs was determined in endometrium from cyclic and pregnant ewes; ISGs were confirmed in cyclic ewes that were infused with IFNtau into the uterus. These studies found that most ISGs are increased in the endometrial stroma and glandular epithelium using signal transducer and activator of transcription 1 (Statl)-dependent pathways. Most ISGs are not induced or increased by IFNtau in the Stat1-negative endometrial luminal epithelium. Recent experiments have used human 2fTGH and U3A (Stat1 null) cells to determine the IFNtau signaling pathway and discover ISGs regulated by IFNtau using transcriptional profiling. Given that ISGs are increased in the endometrium during pregnancy across diverse species, they may be important in establishment of uterine receptivity to implantation of the conceptus.

Dehydroepiandrosterone sulphate sulphohydrolase [correction of sulphoydrolase] from human placenta microsomes--properties of the purified enzyme

A form of steroid sulphate sulphohydrolase (EC 3.1.6.2) hydrolysing the dehydroepiandrosterone sulphate (DHEAS-ase) was purified from human placenta microsomes. During the purification procedure the DHEAS-ase was separated from the oestrone sulphate sulphohydrolase (OS-ase). The purified DHEAS-ase revealed specific activity of 1520 nmolxmin-1xmgprotein-1 and exhibited optimal activity at pH 8.4. The Km value was established to be 3.3+/-0.07x10(-5) M. The pI value was around 8.7. The molecular weight estimated by gel filtration was 7.4 kDa. The purified DHEAS-ase was not sensitive to the common sulphohydrolase inhibitors, such as phosphate, sulphate and sulphide ions, but was inhibited by several phosphohydrolase inhibitors (ammonium molybdate, vanadium oxide(V), zinc acetate). Steroids effected inhibition or activation of the purified enzyme. The data concerning substances reacting with -SH groups suggest that in the physiological conditions DHEAS-ase is controlled by the redox status of the cell.

[Function of PAT family proteins in the lipid metabolism]

Triglycerides are stored in intracellular lipid droplets in mammalian cells. Current evidences suggest that the intracellular lipid droplets are active participants in a variety of metabolic processes, and thus are considered as functional organelles in cells. The lipid droplet is composed of a triglyceride core surrounded by a phospholipid monolayer in which several proteins are embedded. Four of these proteins belong to a family of structurally related PAT protein, which includes perilipin, ADRP, TIP47 and S3-12. In this review, we summarize the functions of these proteins in the modulation of lipolysis and lipid droplets formation.

Pregnancy-associated exosomes and their modulation of T cell signaling

Exosome release by viable cells is a feature of activated cell types, including tumors, fetal cells, and cells of the immune system. Exosomes critically regulate immune activation, by mediating activation-induced cell death. Fetal cells may mimic these events to selectively delete reactive lymphocytes. In this study the presence and composition of placenta-derived exosomes are demonstrated in the maternal circulation along with their consequences on T cell activation markers. For all pregnant patients, exosomes were isolated from sera obtained between 28 and 30 wk gestation. For pregnant women, subsequently delivering at term, circulating levels of placental exosomes were 1.8 times greater than those delivering preterm (p < 0.0001). Exosomes isolated from pregnancies subsequently delivering at term expressed significantly higher levels of biologically active components, including Fas ligand (FasL) and HLA-DR, than those from pregnancies delivering preterm. Standardizing for protein concentrations, exosomes from term-delivering pregnancies exhibited greater suppression of CD3-zeta and JAK3 than those delivering preterm. The suppression of CD3-zeta and JAK3 correlated with exosome expression levels of FasL (r2= 0.92 and r2= 0.938, respectively). Fractionation of exosomes from term-delivering pregnancies by continuously eluting electrophoresis indicated that intact 42 kD FasL and an unidentified 24-kDa protein were associated with CD3-zeta suppression. Our results demonstrated that exosomes from pregnancies ultimately delivering at term are present at significantly greater concentrations than those from pregnancies delivering preterm; however, exosomes from term-delivering pregnancies also exhibit significantly greater suppression of CD3-zeta and JAK3.

Analysis of placental regulation of hematopoiesis

Placental hormones contribute to changes in maternal physiology, especially to changes in the blood system. Methods are described to express a placental hormone from a cloned cDNA by transfection into a mammalian cell line, to purify the hormone, and to assess the activities of the hormone in primary mouse bone marrow cell cultures. The example used in this chapter is prolactin-like protein F (PLP-F), a recently discovered mouse placental hormone that acts on the myeloid lineage. This hormone has been expressed at high levels in stably transfected Chinese hamster ovary cells. The protein is secreted from these cells after cleavage of the signal sequence and the addition of N-linked carbohydrate. A series of chromatographic steps are used to purify the protein to homogeneity, which is verified by gel electrophoresis and silver staining; the identity of the purified protein is confirmed by immunoblot analysis. Purified protein is then assayed by addition to primary bone marrow cells and scoring the growth and the differentiation of the megakaryocyte progenitor, colony forming unit-megakaryocyte.

Hypoxia inhibits differentiation of lineage-specific Rcho-1 trophoblast giant cells

Defects in placental development lead to pregnancies at risk for miscarriage and intrauterine growth retardation and are associated with preeclampsia, a leading cause of maternal death and premature birth. In preeclampsia, impaired placental formation has been associated with alterations in a specific trophoblast lineage, the invasive trophoblast cells. In this study, an RT-PCR Trophoblast Gene Expression Profile previously developed by our laboratory was utilized to examine the lineage-specific gene expression of the rat Rcho-1 trophoblast cell line. Our results demonstrated that Rcho-1 cells represent an isolated, trophoblast population committed to the giant cell lineage. RT-PCR analysis revealed that undifferentiated Rcho-1 cells expressed trophoblast stem cell marker, Id2, and trophoblast giant cell markers. On differentiation, Rcho-1 cells downregulated Id2 and upregulated Csh1, a marker of the trophoblast giant cell lineage. Neither undifferentiated nor differentiated Rcho-1 cells expressed spongiotrophoblast marker Tpbpa or labyrinthine markers Esx1 and Tec. Differentiating Rcho-1 cells in hypoxia did not alter the expression of lineage-specific markers; however, hypoxia did inhibit the downregulation of the trophoblast stem cell marker Id2. Differentiation in hypoxia also blocked the induction of CSH1 protein. In addition, hypoxia inhibited stress fiber formation and abolished the induction of palladin, a protein associated with stress fiber formation and focal adhesions. Thus, Rcho-1 cells can be maintained as a proliferative, lineage-specific cell line that is committed to the trophoblast giant cell lineage on differentiation in both normoxic and hypoxic conditions; however, hypoxia does inhibit aspects of trophoblast giant cell differentiation at the molecular, morphological, and functional levels.

Estrogen regulates transcription of the ovine oxytocin receptor gene through GC-rich SP1 promoter elements

Establishment of pregnancy in ruminants results from paracrine signaling by interferon tau (IFNT) from the conceptus to uterine endometrial luminal epithelia (LE) that prevents release of luteolytic prostaglandin F(2alpha) pulses. In cyclic and pregnant ewes, progesterone down-regulates progesterone receptor (PGR) gene expression in LE. In cyclic ewes, loss of PGR allows for increases in estrogen receptor alpha (ESR1) and then oxytocin receptor (OXTR) gene expression followed by oxytocin-induced prostaglandin F(2alpha) pulses. In pregnant ewes, IFNT inhibits transcription of the ESR1 gene, which presumably inhibits OXTR gene transcription. Alternatively, IFNT may directly inhibit OXTR gene transcription. The 5' promoter/enhancer region of the ovine OXTR gene was cloned and found to contain predicted binding sites for activator protein 1, SP1, and PGR, but not for ESR1. Deletion analysis showed that the basal promoter activity was dependent on the region from -144 to -4 bp that contained only SP1 sites. IFNT did not affect activity of the OXTR promoter. In cells transfected with ESR1, E2, and ICI 182,780 increased promoter activity due to GC-rich SP1 binding sites at positions -104 and -64. Mutation analyses showed that the proximal SP1 sites mediated ESR1 action as well as basal activity of the promoter. In response to progesterone, progesterone receptor B also increased OXTR promoter activity. SP1 protein was constitutively expressed and abundant in the LE of the ovine uterus. These results support the hypothesis that the antiluteolytic effects of IFNT are mediated by direct inhibition or silencing of ESR1 gene transcription, thereby precluding ESR1/SP1 from stimulating OXTR gene transcription.

The Progesterone-Induced Blocking Factor Modulates the Balance of PKC and Intracellular Ca++

PROBLEM

Progesterone-induced blocking factor (PIBF) induces Th2 biased cytokine production; therefore, this study investigates the effects of PIBF on the protein kinase C (PKC)/Ca(++) system - which plays a key role in Th1/Th2 differentiation.

METHOD OF STUDY

Proteins from PIBF-treated cells were reacted on Western blots with phospho-specific antibodies recognizing different PKC izoforms. Intracellular free calcium was measured by flow cytometry.

RESULTS

Both interleukin (IL)-4 and PIBF induced PKC phosphorylation, which was abrogated by anti-IL-4Ralpha or anti-PIBF immunoglobulin G pre-treatment. PIBF treatment did not alter intracellular Ca(++) levels. Inhibition of PKCzeta or PKCtheta phosphorylation, but not that of PKCalpha/beta resulted in the loss of STAT6 and Jak1 phosphorylation by PIBF.

CONCLUSIONS

Our data show that PIBF phosphorylates PKC via binding to the IL-4R, without affecting intracellular Ca(++). Phosphorylation of PKCzeta and PKCtheta is required for Jak1 and STAT6 activation, whereas PKCalpha/beta is not involved. These findings explain the mechanism by which PIBF supports a Th2 dominant cytokine pattern.

Increased immunohistochemical expression of thrombomodulin at placental perivascular myofibroblast in severe preeclampsia (PE)

The presence of pro-coagulant and anti-coagulant components of the placental vascular endothelium and syncytiotrophoblast are essential for homeostasis. Vascular endothelium prevents blood clot formation in vivo by involving a cell surface thrombin-binding glycoprotein, thrombomodulin (TM), that activates plasma anti-coagulant protein C. The TM levels increase during pregnancy, but the fibrinolytic capacity diminishes. Since vascular lesions with placental coagulation disorders can be associated with preeclampsia (PE), we hypothesized that TM expression in the stem villous vasculature and syncytiotrophoblast of the placenta are impaired in PE. Plasma and placental tissue samples were collected from PE (n=12) and normotensive pregnant patients (n=11). Patient's gestational age was 35.7+/-1.2 (normotensive) and 30.6+/-1.5 weeks (PE). Blood samples were drawn 30 min before delivery. Serum PAI-1 and PAI-2 antigens were determined by enzyme-linked immunoabsorbent assay (ELISA). A monoclonal antibody specific for TM was used for immunohistochemical tissue staining (ABC) and the staining was quantified by semi quantitative scores. Results show no intensity differences at the apical syncytiotrophoblast between the two groups. However, in preeclamptic placenta, TM expression diminished in the endothelium of the stem villi arteries and increased in the perivascular and stromal myofibroblats in cases of severe PE. TM changes were associated with an increased PAI-1/PAI-2 ratio. It is suggested that in severe PE, the decreased placental blood flow may be due to structural and functional impairment of the endothelium of the stem villi vessels and the surrounding perivascular and stromal myofibroblast, by increasing TM expression which may modulate fetal blow flow in the villous tree.

Demilune cell and parotid protein from murine oviductal epithelium stimulates preimplantation embryo development

In mammals, fertilization and early preimplantation embryo development occur in the oviduct. We hypothesized that interaction exists between the developing embryos and the maternal genital tract, such that the embryos modulate the physiology and gene expression of the oviduct so that it is conducive to their development. By comparing the gene expression patterns in mouse oviducts containing transferred preimplantation embryos with those of oviducts containing oocytes, we report here the characterization of demilune cell and parotid protein (Dcpp), which was up-regulated in the embryo-containing oviduct. Dcpp mRNA was highly expressed in the oviductal epithelium at the estrus stage. The Dcpp gene codes for a protein of 150 amino acids and contains a signal peptide suggestive of secretory function. The Dcpp mRNA level was maintained in the oviductal epithelium of pregnant females but decreased continuously in those of pseudopregnant mice. Exogenous estrogen stimulated the expression of Dcpp mRNA and protein in ovariectomized mice. The effect was abolished by an estrogen antagonist, ICI 182,780. Dcpp protein was present in mouse oviductal fluid but not in uterine fluid. More importantly, Dcpp immunoreactivity was found in embryos recovered from the oviduct but not in mature oocytes from the ovary. Supplementation of Dcpp to culture medium stimulated the development of mouse embryos to the blastocyst stage. Anti-Dcpp antibody decreased the beneficial effect of Dcpp on implantation of two-cell mouse embryos transferred to the oviducts of the foster mothers. In summary, our data demonstrated that Dcpp is highly expressed in the oviductal lumen in the presence of preimplantation embryos. It stimulates the growth of preimplantation embryos and may play an important role in embryo-maternal dialogue.

In vivo expression of interferon tau mRNA by the embryonic trophoblast and uterine concentrations of interferon tau protein during early pregnancy in the cow

In this study, we have measured uterine concentrations of interferon tau and intensity of embryonic interferon tau mRNA expression between day 14 and 18 in cows. While interferon tau concentrations rose dramatically (P < 0.001) from day 14 to 18, there was no significant increase in the intensity of expression of interferon tau mRNA by the trophoblast. When results were analyzed on the basis of embryo size, well elongated embryos (>10 cm) produced significantly (P < 0.001) more interferon tau than smaller embryos but showed similar levels of interferon tau mRNA expression. These results demonstrate that the increase in interferon tau concentrations responsible for the maternal recognition of pregnancy results from the increase in embryo size during elongation and not from any upregulation of mRNA expression.

Functions of alpha 2 macroglobulins in pregnancy

The alpha 2 macroglobulins (A2M) are a family of abundant plasma proteins produced predominantly by the mammalian liver. Pregnancy zone proteins (PZP) of humans and rats are A2M family members that bind a wide variety of macromolecules including the important pregnancy-associated molecules such as vascular endothelial growth factor, placenta growth factor and glycodelin (also called PP14). Recently, a mouse gene analogous to PZP (A2M of pregnancy or A2Mp) was cloned. A2Mp has a unique pattern of expression in reproductive and cardiovascular tissues and, unexpectedly, is not expressed by liver. Since changes in heart function and remodeling of renal and uterine vasculature are amongst the earliest maternal responses to pregnancy, the product of the A2Mp gene has been postulated to systemically regulate these changes. A2Ms with and without non-covalently bound ligands also down regulate immune cell activation but promote immune cell migration, additional features associated with gestational success. Here, we review the A2M gene families of mice and humans, the predicted structural relationships between A2M and its pregnancy induced forms and the postulated roles for this gene family in normal pregnancy.

Embryonic expression of murine 5T4 oncofoetal antigen is associated with morphogenetic events at implantation and in developing epithelia

Overexpression of 5T4 oncofoetal antigen, an early marker of ES cell differentiation, in vitro increases cellular motility and decreases adhesion, properties relevant to development and cancer. Embryonic expression of m5T4 antigen is first detected on trophectoderm at implantation and is restricted to extra-embryonic tissues to embryonic day (E) 11.5. In the embryo, significant m5T4 expression is detected at E12.5 in hindbrain roofplate and in various epithelia derived from all germ layers. In keratin 14-expressing epithelia, there is a congruent 5T4 expression pattern with many of these cells being Ki-67 positive. In brain, expression is observed in roofplate, ependymal layers, choroid plexus, and subventricular zones of lateral ventricles at E14.5. By E17.5, expression is decreased in the subventricular zone with further restriction to choroid plexus in adult brain. Our data demonstrate a limited 5T4 expression profile during embryogenesis associated with actively cycling, undifferentiated epithelial progenitor cells that may contribute to their migration.

Glycodelin reduces carcinoma-associated gene expression in endometrial adenocarcinoma cells

OBJECTIVE

Glycodelin is a major secretory glycoprotein of differentiated endometrial epithelium, rarely expressed in proliferative endometrium or endometrial cancer. We aimed to elucidate its role in growth and gene expression of endometrial adenocarcinoma cells, and hypothesized that glycodelin affects cell growth and tumor-associated gene expression.

STUDY DESIGN

Endometrial adenocarcinoma HEC-1B cells were transfected with glycodelin cDNA in both antisense and sense orientations. Cellular morphology, cell proliferation, and gene expression were compared between native and transfected cells.

RESULTS

Compared with native and antisense-transfected carcinoma cells, sense-transfected, glycodelin-producing carcinoma cells showed reduced proliferation, morphologic changes, and altered expression of cancer-related genes. Notably, anti-apoptotic Bcl-XL and MUC1 genes were down-regulated.

CONCLUSION

Reduction by glycodelin transfection of carcinoma cell proliferation and expression of MUC1 and Bcl-XL is significant because these genes are often overexpressed in human cancers--MUC1 is linked to invasive growth and metastases, and both confer resistance to chemotherapy. These results suggest a novel mechanism whereby malignant growth of endometrial adenocarcinoma cells is regulated.

The placenta growth factor in skin angiogenesis

The placenta growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family that has been shown to play an important role in promoting adult pathological angiogenesis. Besides inducing its own signaling in endothelial cells, PlGF exerts its angiogenic action by synergising with VEGF. In the skin, PlGF expression is upregulated during wound healing and PlGF-deficient mice show delayed wound closure, indicating that this factor promotes angiogenesis during skin repair. Moreover, PlGF expression by melanoma cells has been linked to tumor growth. The analysis of a transgenic mouse model constitutively expressing high levels of PlGF in basal keratinocytes has shown that this factor has strong angiogenic properties in the skin during both embryonic and post-natal life. Furthermore, PlGF delivery to the skin via an adenoviral vector induces the formation of large and stable blood vessels, but contrary to VEGF application, does not affect lymphatic vessel functionality. Such evidence opens the possibility of employing PlGF for therapeutic modulation of skin angiogenesis.

Placenta growth factor stimulates the growth of Philadelphia chromosome positive acute lymphoblastic leukemia cells by both autocrine and paracrine pathways

Vascular endothelial growth factor (VEGF) and its associated molecule, placenta growth factor (PlGF) are now known to support normal hematopoiesis, and leukemia cell growth. In this study, expression of VEGF and PlGF in acute lymphoblastic leukemia (ALL) cells was examined by real time reverse transcription-polymerase chain reaction in 20 patient samples. Expression of PlGF was more intense in Philadelphia chromosome positive (Ph(+)) ALL than in Ph(-) ALL cases. On the other hand, expression level of VEGF was not different between Ph(+) and Ph(-) cases. Then, PlGF was added to the two ALL cell lines, CRL1929 (Ph(+)), and Nalm6 (Ph(-)). The PlGF stimulated the growth of CRL1929 in time- and dose-dependent manners, although the growth of Nalm6 was not affected by PlGF. The growth stimulation of CRL1929 by PlGF was confirmed by the increase of S phase cells. And the growth promoting effect of PlGF on CRL1929 was cancelled by simultaneous addition of VEGFR1/Fc (which binds to PlGF and abrogates its function), but was not cancelled by VEGFR2/Fc (which does not bind to PlGF). Then, addition of VEGFR1/Fc to the simple culture of CRL1929 demonstrated growth inhibitory effect. These observations demonstrated that PlGF stimulates the growth of Ph(+) ALL cells by both autocrine and paracrine pathways. Finally, PlGF-VEGFR1 loop might be a therapeutic target to improve the prognosis of Ph(+) ALL.

Crystal Structure of a Pivotal Domain of Human Syncytin-2, A 40 Million Years Old Endogenous Retrovirus Fusogenic Envelope Gene Captured by Primates

HERV-FRD is a human endogenous retrovirus that entered the human genome 40 million years ago. Its envelope gene, syncytin-2, was diverted by an ancestral host most probably because of its fusogenic property, for a role in placenta morphogenesis. It was maintained in a functional state in all primate branches as a bona fide cellular gene, submitted to a very low mutation rate as compared to infectious retrovirus genomes. The structure of the syncytin-2 protein thus provides a good insight into that of the oldest mammalian retroviral envelope. Here, we report the crystal structure of a central fragment of its "fossil" ectodomain, allowing a remarkable superposition with the structures of the corresponding domains of present-day infectious retroviruses, in spite of a more than 60% divergent sequence. These results suggest the existence of a unique structural solution selected by these proteins for their fusogenic function.