Yung H.W.,University of Cambridge |
Hemberger M.,University of Cambridge |
Hemberger M.,Babraham Institute |
Watson E.D.,University of Cambridge |
And 9 more authors.
Journal of Pathology | Year: 2012
We recently reported the first evidence of placental endoplasmic reticulum (ER) stress in the pathophysiology of human intrauterine growth restriction. Here, we used a mouse model to investigate potential underlying mechanisms. Eif2s1tm1RjK mice, in which Ser51 of eukaryotic initiation factor 2 subunit alpha (eIF2α) is mutated, display a 30% increase in basal translation. In Eif2s1tm1RjK placentas, we observed increased ER stress and anomalous accumulation of glycoproteins in the endocrine junctional zone (Jz), but not in the labyrinthine zone where physiological exchange occurs. Placental and fetal weights were reduced by 15% (97 mg to 82 mg, p < 0.001) and 20% (1009 mg to 798 mg, p < 0.001), respectively. To investigate whether ER stress affects bioactivity of secreted proteins, mouse embryonic fibroblasts (MEFs) were derived from Eif2s1tm1RjK mutants. These MEFs exhibited ER stress, grew 50% slower, and showed reduced Akt-mTOR signalling compared to wild-type cells. Conditioned medium (CM) derived from Eif2s1tm1RjK MEFs failed to maintain trophoblast stem cells in a progenitor state, but the effect could be rescued by exogenous application of FGF4 and heparin. In addition, ER stress promoted accumulation of pro-Igf2 with altered glycosylation in the CM without affecting cellular levels, indicating that the protein failed to be processed after release. Igf2 is the major growth factor for placental development; indeed, activity in the Pdk1-Akt-mTOR pathways was decreased in Eif2s1tm1RjK placentas, indicating loss of Igf2 signalling. Furthermore, we observed premature differentiation of trophoblast progenitors at E9.5 in mutant placentas, consistent with the in vitro results and with the disproportionate development of the labyrinth and Jz seen in placentas at E18.5. Similar disproportion has been reported in the Igf2-null mouse. These results demonstrate that ER stress adversely affects placental development, and that modulation of post-translational processing, and hence bioactivity, of secreted growth factors contributes to this effect. Placental dysmorphogenesis potentially affects fetal growth through reduced exchange capacity. Copyright © 2012 Pathological Society of Great Britain and Ireland.
Hiby S.E.,University of Cambridge |
Hiby S.E.,Center for Trophoblast Research |
Apps R.,University of Cambridge |
Apps R.,Center for Trophoblast Research |
And 22 more authors.
Journal of Clinical Investigation | Year: 2010
Many common disorders of pregnancy are attributed to insufficient invasion of the uterine lining by trophoblast, fetal cells that are the major cell type of the placenta. Interactions between fetal trophoblast and maternal uterine NK (uNK) cells - specifically interactions between HLA-C molecules expressed by the fetal trophoblast cells and killer Ig-like receptors (KIRs) on the maternal uNK cells - influence placentation in human pregnancy. Consistent with this, pregnancies are at increased risk of preeclampsia in mothers homozygous for KIR haplotype A (KIR AA). In this study, we have demonstrated that trophoblast expresses both paternally and maternally inherited HLA-C surface proteins and that maternal KIR AA frequencies are increased in affected pregnancies only when the fetus has more group 2 HLA-C genes (C2) than the mother. These data raise the possibility that there is a deleterious allogeneic effect stemming from paternal C2. We found that this effect also occurred in other pregnancy disorders (fetal growth restriction and recurrent miscarriage), indicating a role early in gestation for these receptor/ligand pairs in the pathogenesis of reproductive failure. Notably, pregnancy disorders were less frequent in mothers that possessed the telomeric end of the KIR B haplotype, which contains activating KIR2DS1. In addition, uNK cells expressed KIR2DS1, which bound specifically to C2+ trophoblast cells. These findings highlight the complexity and central importance of specific combinations of activating KIR and HLA-C in maternal-fetal immune interactions that determine reproductive success.
Jones C.J.P.,University of Manchester |
Aplin J.D.,University of Manchester |
Burton G.J.,Center for Trophoblast Research
Placenta | Year: 2010
Objectives: Histiotrophe is now recognized as being an important feature of early human pregnancy, providing nutrients and growth factors to the developing embryo. Our aim was to examine the glycan composition of histiotrophe from first trimester decidua and to compare it with secretions present in endometrial glands from the late secretory phase of the menstrual cycle. Study design: Twenty samples of decidua from pregnancies between 8 and 11 weeks were processed into epoxy resin and sections stained with a panel of 22 lectins, together with six late secretory phase endometrial biopsies. Main outcome measures: Specimens were analysed using a semi-quantitative ranking system and the density of lectin binding to the glandular secretions and the epithelium assessed. Results: With the onset of pregnancy, β-galactose, α-N-acetyl galactosamine and N-Acetyl lactosamine bound by Arachis hypogaea, Glycine max, Helix pomatia and Erythrina crystagalli agglutinins appeared in terminal positions on oligosaccharide chains, suggesting loss of the capping sialic acid residues present in the non-pregnant state. Conclusions: Suppression of terminal sialylation is evident during early pregnancy, suggesting that modifications to endometrial glandular activity occur in response to placental signals. The changes may facilitate absorption of histiotrophe by the trophoblast and enhance availability of substrates for degradation. © 2010 Elsevier Ltd. All rights reserved.
Burton G.J.,Center for Trophoblast Research |
Scioscia M.,Sacro Cuore Don Calabria |
Rademacher T.W.,University College London |
Rademacher T.W.,University of Oxford
Journal of Reproductive Immunology | Year: 2011
Endometrial glands represent an important source of nutrients for the conceptus during the first trimester. Their secretions are enriched with carbohydrates, and glycogen accumulates within the syncytiotrophoblast of the placenta. It has been assumed that fetal and placental metabolism follow adult pathways, although it is now appreciated that early development occurs in a low-oxygen environment. In past decades, a novel family of putative insulin mediators, inositol phosphoglycans (IPGs), was discovered. These molecules act as allosteric activators and/or inhibitors of enzymes and transduction proteins involved in the control of cell signalling and metabolic pathways, and determine the specificity of responses after activation of the insulin receptor. One member, IPG P-type, activates pyruvate dehydrogenase phosphatase (PDH-Pase), glycogen synthase phosphatase, and glycerol-3-phosphate acyltransferase. Activation of key phosphatases play a major role in the regulation of glucose disposal by oxidative metabolism via PDH, and the non-oxidative storage by glycogen synthesis, both pathways classically known to be regulated by insulin. High concentrations of IPG P-type in amniotic fluid suggest a role in the regulation of carbohydrate metabolism in the fetal-placental unit. Glycogen accumulation in the syncytiotrophoblast also occurs in preeclamptic pregnancies, and is consistently associated with higher placental levels of IPG P-type. Here, we explore the relationship between nutrients provided by the endometrial glands during early pregnancy, IPG P-type and fetal metabolic requirements. We also discuss whether a disconnect between the placental/fetal metabolic state and oxygen tension could lead to a preeclamptic-type syndrome via leakage of Warburg/IPG mediators into the maternal circulation. © 2011.
Burke K.A.,Center for Trophoblast Research |
Jauniaux E.,University College London |
Burton G.J.,Center for Trophoblast Research |
Cindrova-Davies T.,Center for Trophoblast Research
Placenta | Year: 2013
Megalin and cubilin are multifunctional endocytic receptors associated with many transporting epithelia. They play an essential role in transport of nutrients through the visceral yolk sac of rodents during embryogenesis. Here, we immunolocalise them to the endodermal layer of the human yolk sac, and to the syncytiotrophoblast and cytotrophoblast cells of placental villi. In villi, the protein level of both receptors increased with gestation. The mRNA for megalin remained constant, while that encoding cubilin increased with gestation. These results suggest megalin and cubilin may be important in human maternal-fetal transfer, and that they increase across gestation to facilitate this function. © 2013 Elsevier Ltd. All rights reserved.
Jedrusik A.,Wellcome Trust CR UK Gurdon Institute |
Jedrusik A.,Center for Trophoblast Research
Reproductive BioMedicine Online | Year: 2013
Early mammalian development consists of two distinct phases separated by the event of implantation. Whereas much has been discovered about developmental mechanisms prior to implantation, the inability to culture and follow in real time cell behaviour over the period of implantation means that the second phase has not been explored in as much detail. Recently, a novel in-vitro culture system was described that permits continuous culture and time-lapse observations through the peri- and early post-implantation stages. This system has already delivered detailed information on the cellular processes accompanying early morphogenesis and allowed direct connections to be established between events occurring at the two developmental phases. This review discusses the potential of this novel technology and its possible applications that could have not only impact on basic science but also practical implications for human medicine. © 2013, Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.
Burton G.J.,Center for Trophoblast Research |
Fowden A.L.,Center for Trophoblast Research
Placenta | Year: 2012
The placenta evolved to support development of the fetus, and so potentially plays a key role in the aetiology of developmental programming through its impact on nutrient transfer. Placental transport efficiency depends on a variety of parameters, including surface area for exchange, thickness of the interhaemal membrane and density of transporter proteins inserted into the trophoblast membranes. Here, we review recent studies that tested whether adaptations of placental efficiency are induced in the mouse placenta when maternal nutrient supply and fetal demand are manipulated experimentally. Naturally small placentas, and those exposed to maternal undernutrition, displayed structural changes indicative of accelerated maturation at E16, with enlargement of the labyrinth exchange zone at the expense of the endocrine junctional zone. These changes were associated with increased transport of a non-metabolisable amino acid analogue per gram of placenta, and expression of genes encoding specific System A transporters. Up-regulation of transporters was also observed when a mismatch between placental size and fetal demand was generated through genetic manipulation of the Igf2/H19 axis. Conversely, overgrowth of the placenta induced by deletion of H19 resulted in reduced transport capacity and expression of transporter genes. We conclude that under conditions when the maternal nutrient supply or placental size may be limiting for normal fetal growth, the placenta adapts so as to increase its transport capacity. Hence, it ameliorates the effects of environmental cues that would otherwise lead to more extensive developmental programming. The P0 transcript of Igf2 appears to be a strong candidate as a mediator of these adaptations in the mouse. © 2012 Published by IFPA and Elsevier Ltd.
Johnson M.H.,Center for Trophoblast Research
Reproductive BioMedicine Online | Year: 2011
The early influences on Robert Edwards' approach to the scientific research that led to human IVF are described. His interest as a graduate student in the genetics of early mammalian development stimulated him later to investigate whether the origins of human genetic diseases such as Down, Klinefelter and Turner syndromes might be explained by events during egg maturation. This clinical problem provided the most powerful stimulus to achieve both oocyte maturation and fertilization in vitro in humans. Indeed, preimplantation genetic diagnosis was his main goal until he met Patrick Steptoe in 1968. A re-evaluation of his meeting with Steptoe suggests that initially Steptoe's laparoscopic skill was of interest for its potential to solve the sperm capacitation problem. Steptoe's impact on Edwards was twofold. First, Steptoe's long-held interest in infertility raised this application of IVF higher in Edwards' priorities. Second, Steptoe offered a long-term partnership, in which oocyte collection without in-vitro maturation was a possibility. The professional criticism generated by their work together encouraged Edwards to pursue a deliberate programme of public education about the issues raised and to challenge and develop professional bioethical thought and discourse about reproduction. The early life and career of Robert Edwards are described and re-evaluated in the light of documentary evidence. His early interest in the genetics of development provided the major motivation behind his goal of achieving IVF in humans. Through this work, he aimed to understand and hopefully to reduce the transmission of genetic disease in humans. His meeting with Patrick Steptoe, the details of which are re-examined, increased the significance for Edwards of infertility as an outcome of IVF. It also led to a creative long-term research partnership, initiated a long-term programme of public education in the UK about reproductive science and stimulated the development of bioethical thinking. © 2011, Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.
Vaughan O.R.,Center for Trophoblast Research |
Sferruzzi-Perri A.N.,Center for Trophoblast Research |
Coan P.M.,Center for Trophoblast Research |
Fowden A.L.,Center for Trophoblast Research
Biology of Reproduction | Year: 2013
Synthetic glucocorticoids, like dexamethasone (dex), restrict growth of the fetus and program its adult physiology, in part by altering placental phenotype. The route and timing of dex administration determine the fetal and adult outcomes, but whether these factors affect placental phenotype remains unknown. This study compared placental morphology, amino acid transport, and gene expression in mice given dex orally or by subcutaneous injection over the periods of most rapid placental (Days [D] 11-16) or fetal (D14-19) growth (term is D21). Compared with untreated and saline-injected controls, both dex treatments reduced placental weight at D16 and 19 and fetal weight and total labyrinthine volume at D19 to a similar extent. Only oral dex treatment from D11 to D16 reduced labyrinthine fetal capillary volume on D16 and increased placental 14C-methylaminoisobutyric acid (MeAIB) clearance at D19, 3 days after treatment ended. Neither route of dex treatment altered placental expression of Slc38a, Hsd11b, or the glucocorticoid receptor, Nr3c1, at D16. In contrast, both routes of dex treatment from D14 to D19 increased placental Hsd11b2 expression and labyrinthine maternal vessel volume. Furthermore, injection per se altered placental expression of Nr3c1, Hsd11b1, and specific Slc38a isoforms in an age-related manner. Overall, MeAIB clearance was not related to Slc38a transporter expression but was correlated inversely with maternal corticosterone concentrations when dex was undetectable in maternal plasma at D19. The effects of dex on placental phenotype, therefore, depend on both the route and timing of administration and may relate to local glucocorticoid availability during and after the treatment period © 2013 by the Society for the Study of Reproduction, Inc.
PubMed | Center for Trophoblast Research
Type: Journal Article | Journal: The Journal of physiology | Year: 2012
Stresses during pregnancy that increase maternal glucocorticoids reduce birth weight in several species. However, the role of natural glucocorticoids in the mother in fetal acquisition of nutrients for growth remains unknown. This study aimed to determine whether fetal growth was reduced as a consequence of altered amino acid supply when mice were given corticosterone in their drinking water for 5 day periods in mid to late pregnancy (day, D, 11-16 or D14-19). Compared to controls drinking tap water, fetal weight was always reduced by corticosterone. At D16, corticosterone had no effect on materno-fetal transfer of [(14)C]methylaminoisobutyric acid (MeAIB), although placental MeAIB accumulation and expression of the Slc38a1 and Slc38a2 transporters were increased. However, at D19, 3 days after treatment ended, materno-fetal transfer of MeAIB was increased by 37% (P < 0.04). During treatment at D19, placental accumulation and materno-fetal transfer of MeAIB were reduced by 40% (P < 0.01), although expression of Slc38a1 was again elevated. Permanent reductions in placental vascularity occurred during the earlier but not the later period of treatment. Placental Hsd11b2 expression, which regulates feto-placental glucocorticoid bioavailability, was also affected by treatment at D19 only. Maternal corticosterone concentrations inversely correlated with materno-fetal MeAIB clearance and fetal weight at D19 but not D16. On D19, weight gain of the maternal carcass was normal during corticosterone treatment but reduced in those mice treated from D11 to D16, in which corticosterone levels were lowest. Maternal corticosterone is, therefore, a physiological regulator of the amino acid supply for fetal growth via actions on placental phenotype.