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Shimada H, Powell TL, Jansson T. Regulation of placental amino acid transport in health and disease. Acta Physiol (Oxf) 2024; 240:e14157. [PMID: 38711335 PMCID: PMC11162343 DOI: 10.1111/apha.14157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 04/19/2024] [Accepted: 04/23/2024] [Indexed: 05/08/2024]
Abstract
Abnormal fetal growth, i.e., intrauterine growth restriction (IUGR) or fetal growth restriction (FGR) and fetal overgrowth, is associated with increased perinatal morbidity and mortality and is strongly linked to the development of metabolic and cardiovascular disease in childhood and later in life. Emerging evidence suggests that changes in placental amino acid transport may contribute to abnormal fetal growth. This review is focused on amino acid transport in the human placenta, however, relevant animal models will be discussed to add mechanistic insights. At least 25 distinct amino acid transporters with different characteristics and substrate preferences have been identified in the human placenta. Of these, System A, transporting neutral nonessential amino acids, and System L, mediating the transport of essential amino acids, have been studied in some detail. Importantly, decreased placental Systems A and L transporter activity is strongly associated with IUGR and increased placental activity of these two amino acid transporters has been linked to fetal overgrowth in human pregnancy. An array of factors in the maternal circulation, including insulin, IGF-1, and adiponectin, and placental signaling pathways such as mTOR, have been identified as key regulators of placental Systems A and L. Studies using trophoblast-specific gene targeting in mice have provided compelling evidence that changes in placental Systems A and L are mechanistically linked to altered fetal growth. It is possible that targeting specific placental amino acid transporters or their upstream regulators represents a novel intervention to alleviate the short- and long-term consequences of abnormal fetal growth in the future.
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Affiliation(s)
- Hiroshi Shimada
- Department of Obstetrics and Gynecology University of Colorado, Anschutz Medical Campus, Aurora, CO, US
- Departments of Obstetrics & Gynecology, Sapporo Medical University, Sapporo, Japan
| | - Theresa L Powell
- Department of Obstetrics and Gynecology University of Colorado, Anschutz Medical Campus, Aurora, CO, US
- Department of Pediatrics, University of Colorado, Anschutz Medical Campus, Aurora, CO, US
| | - Thomas Jansson
- Department of Obstetrics and Gynecology University of Colorado, Anschutz Medical Campus, Aurora, CO, US
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Down-regulation of placental Cdc42 and Rac1 links mTORC2 inhibition to decreased trophoblast amino acid transport in human intrauterine growth restriction. Clin Sci (Lond) 2020; 134:53-70. [PMID: 31825077 DOI: 10.1042/cs20190794] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 11/26/2019] [Accepted: 12/11/2019] [Indexed: 12/31/2022]
Abstract
Intrauterine growth restriction (IUGR) increases the risk for perinatal complications and metabolic and cardiovascular disease later in life. The syncytiotrophoblast (ST) is the transporting epithelium of the human placenta, and decreased expression of amino acid transporter isoforms in the ST plasma membranes is believed to contribute to IUGR. Placental mechanistic target of rapamycin Complex 2 (mTORC2) signaling is inhibited in IUGR and regulates the trafficking of key amino acid transporter (AAT) isoforms to the ST plasma membrane; however, the molecular mechanisms are unknown. Cdc42 and Rac1 are Rho-GTPases that regulate actin-binding proteins, thereby modulating the structure and dynamics of the actin cytoskeleton. We hypothesized that inhibition of mTORC2 decreases AAT expression in the plasma membrane and amino acid uptake in primary human trophoblast (PHT) cells mediated by down-regulation of Cdc42 and Rac1. mTORC2, but not mTORC1, inhibition decreased the Cdc42 and Rac1 expression. Silencing of Cdc42 and Rac1 inhibited the activity of the System L and A transporters and markedly decreased the trafficking of LAT1 (System L isoform) and SNAT2 (System A isoform) to the plasma membrane. mTORC2 inhibition by silencing of rictor failed to decrease AAT following activation of Cdc42/Rac1. Placental Cdc42 and Rac1 protein expression was down-regulated in human IUGR and was positively correlated with placental mTORC2 signaling. In conclusion, mTORC2 regulates AAT trafficking in PHT cells by modulating Cdc42 and Rac1. Placental mTORC2 inhibition in human IUGR may contribute to decreased placental amino acid transfer and reduced fetal growth mediated by down-regulation of Cdc42 and Rac1.
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Chassen S, Jansson T. Complex, coordinated and highly regulated changes in placental signaling and nutrient transport capacity in IUGR. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165373. [PMID: 30684642 PMCID: PMC6650384 DOI: 10.1016/j.bbadis.2018.12.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/20/2018] [Accepted: 12/26/2018] [Indexed: 01/01/2023]
Abstract
The most common cause of intrauterine growth restriction (IUGR) in the developed world is placental insufficiency, a concept often used synonymously with reduced utero-placental and umbilical blood flows. However, placental insufficiency and IUGR are associated with complex, coordinated and highly regulated changes in placental signaling and nutrient transport including inhibition of insulin and mTOR signaling and down-regulation of specific amino acid transporters, Na+/K+-ATPase, the Na+/H+-exchanger, folate and lactate transporters. In contrast, placental glucose transport capacity is unaltered and Ca2+-ATPase activity and the expression of proteins involved in placental lipid transport are increased in IUGR. These findings are not entirely consistent with the traditional view that the placenta is dysfunctional in IUGR, but rather suggest that the placenta adapts to reduce fetal growth in response to an inability of the mother to allocate resources to the fetus. This new model has implications for the understanding of the mechanisms underpinning IUGR and for the development of intervention strategies.
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Affiliation(s)
- Stephanie Chassen
- Department of Pediatrics, Division of Neonatology, University of Colorado, Anschutz Medical Campus, Aurora, USA
| | - Thomas Jansson
- Department of Obstetrics and Gynecology, Division of Reproductive Sciences, University of Colorado, Anschutz Medical Campus, Aurora, USA.
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Castillo-Castrejon M, Jansson T, Powell TL. No evidence of attenuation of placental insulin-stimulated Akt phosphorylation and amino acid transport in maternal obesity and gestational diabetes mellitus. Am J Physiol Endocrinol Metab 2019; 317:E1037-E1049. [PMID: 31573844 PMCID: PMC6962503 DOI: 10.1152/ajpendo.00196.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Pregnancies complicated by obesity and/or gestational diabetes (GDM) are associated with peripheral insulin resistance; however, the insulin responsiveness of the placenta in these pregnancy complications remains largely unknown. We tested the hypothesis that primary human trophoblast cells and placental villous explants will be insulin responsive, characterized by amino acid transport, Akt and Erk activity with maternal obesity, and/or GDM. We evaluated term placentas from women with normal body mass index (BMI) (normal; n = 15), obesity (OB; n = 11), normal BMI with GDM (N-GDM; n = 11), and obesity with GDM (OB-GDM; n = 11). In a subgroup, primary human trophoblast cells (PHT) were isolated, and in an independent subgroup placental villous explants were exposed to varying concentrations of insulin. Amino acid transport capacity and insulin signaling activity were determined. Insulin significantly increased amino acid transport activity to a similar degree in PHT cells isolated from normal (+21%), N-GDM (+38%), OB (+37%), and OB-GDM (+35%) pregnancies. Insulin increased Akt and Erk phosphorylation in PHT cells (3-fold) and in villous explants (2-fold) in all groups to a similar degree. In contrast to the peripheral maternal insulin resistance commonly associated with obesity and/or GDM, we found that the placenta is insulin sensitive in these pregnancy complications. We suggest that elevated maternal insulin levels in pregnancies complicated by obesity and/or GDM promote critical placental functions, including amino acid transport. Insulin-stimulated placental nutrient delivery may contribute to the increased risk of fetal overgrowth and adiposity in these pregnancies. Moreover, our findings may inform efforts to optimize insulin regimens for women with GDM.
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Affiliation(s)
- Marisol Castillo-Castrejon
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Thomas Jansson
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Theresa L Powell
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
- Department of Pediatrics, Section of Neonatology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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James-Allan LB, Arbet J, Teal SB, Powell TL, Jansson T. Insulin stimulates GLUT4 trafficking to the syncytiotrophoblast basal plasma membrane in the human placenta. J Clin Endocrinol Metab 2019; 104:4225-4238. [PMID: 31112275 PMCID: PMC6688457 DOI: 10.1210/jc.2018-02778] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 05/15/2019] [Indexed: 01/30/2023]
Abstract
CONTEXT Placental transport capacity influences fetal glucose supply. The syncytiotrophoblast is the transporting epithelium in the human placenta, expressing glucose transporters (GLUT) and insulin receptors (IR) in its maternal-facing microvillous (MVM) and fetal-facing basal plasma membrane (BM). OBJECTIVE The objectives of this study were to (1) determine the expression of the insulin-sensitive GLUT4 glucose transporter and IR in the syncytiotrophoblast plasma membranes across gestation in normal pregnancy and in pregnancies complicated by maternal obesity and (2) assess the effect of insulin on GLUT4 plasma membrane trafficking in human placental explants. DESIGN, SETTING, PARTICIPANTS Placental tissue was collected across gestation from women with normal body mass index (BMI) and obese mothers with appropriate for gestational age (AGA) and macrosomic infants. MVM and BM were isolated. MAIN OUTCOME MEASURES Protein expression of GLUT4, GLUT1 and IR were determined by western blot. RESULTS GLUT4 was exclusively expressed in the BM and IR was predominantly expressed in the MVM, with increasing expression across gestation. BM GLUT1 expression was increased and BM GLUT4 expression was decreased in obese women delivering macrosomic babies. In placental villous explants incubation with insulin stimulated Akt (S473) phosphorylation (+76%, p=0.0003, n=13) independent of maternal BMI and increased BM GLUT4 protein expression (+77%, p=0.0013, n=7) in placentas from lean but not obese women. CONCLUSION We propose that maternal insulin stimulates placental glucose transport by promoting GLUT4 trafficking to the BM, which may enhance glucose transfer to the fetus in response to postprandial hyperinsulinemia in women with normal BMI.
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Affiliation(s)
- Laura B James-Allan
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
- Correspondence and Reprint Requests: Laura B. James-Allan, PhD, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, 12700 East 19th Avenue, Aurora, Colorado 80045. E-mail:
| | - Jaron Arbet
- Department of Biostatistics and Informatics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Stephanie B Teal
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Theresa L Powell
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Thomas Jansson
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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Vaughan O, Rosario F, Powell T, Jansson T. Regulation of Placental Amino Acid Transport and Fetal Growth. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 145:217-251. [DOI: 10.1016/bs.pmbts.2016.12.008] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Díaz P, Powell TL, Jansson T. The role of placental nutrient sensing in maternal-fetal resource allocation. Biol Reprod 2014; 91:82. [PMID: 25122064 DOI: 10.1095/biolreprod.114.121798] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The placenta mediates maternal-fetal exchange and has historically been regarded as a passive conduit for nutrients. However, emerging evidence suggests that the placenta actively responds to nutritional and metabolic signals from the mother and the fetus. We propose that the placenta integrates a multitude of maternal and fetal nutritional cues with information from intrinsic nutrient-sensing signaling pathways to match fetal demand with maternal supply by regulating maternal physiology, placental growth, and nutrient transport. This process, which we have called placental nutrient sensing, ensures optimal allocation of resources between the mother and the fetus to maximize the chances for propagation of parental genes without jeopardizing maternal health. We suggest that these mechanisms have evolved because of the evolutionary pressures of maternal undernutrition, which result in decreased placental growth and down-regulation of nutrient transporters, thereby limiting fetal growth to ensure maternal survival. These regulatory loops may also function in response to maternal overnutrition, leading to increased placental growth and nutrient transport in cases of maternal obesity or gestational diabetes. Thus, placental nutrient sensing modulates maternal-fetal resource allocation to increase the likelihood of reproductive success. This model implies that the placenta plays a critical role in mediating fetal programming and determining lifelong health.
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Affiliation(s)
- Paula Díaz
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center San Antonio, San Antonio, Texas
| | - Theresa L Powell
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center San Antonio, San Antonio, Texas
| | - Thomas Jansson
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center San Antonio, San Antonio, Texas
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Kavitha JV, Rosario FJ, Nijland MJ, McDonald TJ, Wu G, Kanai Y, Powell TL, Nathanielsz PW, Jansson T. Down-regulation of placental mTOR, insulin/IGF-I signaling, and nutrient transporters in response to maternal nutrient restriction in the baboon. FASEB J 2013; 28:1294-305. [PMID: 24334703 DOI: 10.1096/fj.13-242271] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The mechanisms by which maternal nutrient restriction (MNR) causes reduced fetal growth are poorly understood. We hypothesized that MNR inhibits placental mechanistic target of rapamycin (mTOR) and insulin/IGF-I signaling, down-regulates placental nutrient transporters, and decreases fetal amino acid levels. Pregnant baboons were fed control (ad libitum, n=11) or an MNR diet (70% of controls, n=11) from gestational day (GD) 30. Placenta and umbilical blood were collected at GD 165. Western blot was used to determine the phosphorylation of proteins in the mTOR, insulin/IGF-I, ERK1/2, and GSK-3 signaling pathways in placental homogenates and expression of glucose transporter 1 (GLUT-1), taurine transporter (TAUT), sodium-dependent neutral amino acid transporter (SNAT), and large neutral amino acid transporter (LAT) isoforms in syncytiotrophoblast microvillous membranes (MVMs). MNR reduced fetal weights by 13%, lowered fetal plasma concentrations of essential amino acids, and decreased the phosphorylation of placental S6K, S6 ribosomal protein, 4E-BP1, IRS-1, Akt, ERK-1/2, and GSK-3. MVM protein expression of GLUT-1, TAUT, SNAT-2 and LAT-1/2 was reduced in MNR. This is the first study in primates exploring placental responses to maternal undernutrition. Inhibition of placental mTOR and insulin/IGF-I signaling resulting in down-regulation of placental nutrient transporters may link maternal undernutrition to restricted fetal growth.
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Affiliation(s)
- Jovita V Kavitha
- 2Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center San Antonio, Mail Code 7836, 7703 Floyd Curl Dr., San Antonio, TX 78229-3900, USA.
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Regulation of nutrient transport across the placenta. J Pregnancy 2012; 2012:179827. [PMID: 23304511 PMCID: PMC3523549 DOI: 10.1155/2012/179827] [Citation(s) in RCA: 270] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 09/02/2012] [Indexed: 12/20/2022] Open
Abstract
Abnormal fetal growth, both growth restriction and overgrowth, is associated with perinatal complications and an increased risk of metabolic and cardiovascular disease later in life. Fetal growth is dependent on nutrient availability, which in turn is related to the capacity of the placenta to transport these nutrients. The activity of a range of nutrient transporters has been reported to be decreased in placentas of growth restricted fetuses, whereas at least some studies indicate that placental nutrient transport is upregulated in fetal overgrowth. These findings suggest that changes in placental nutrient transport may directly contribute to the development of abnormal fetal growth. Detailed information on the mechanisms by which placental nutrient transporters are regulated will therefore help us to better understand how important pregnancy complications develop and may provide a foundation for designing novel intervention strategies. In this paper we will focus on recent studies of regulatory mechanisms that modulate placental transport of amino acids, fatty acids, and glucose.
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Rosario FJ, Kanai Y, Powell TL, Jansson T. Mammalian target of rapamycin signalling modulates amino acid uptake by regulating transporter cell surface abundance in primary human trophoblast cells. J Physiol 2012; 591:609-25. [PMID: 23165769 DOI: 10.1113/jphysiol.2012.238014] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Abnormal fetal growth increases the risk for perinatal complications and predisposes for the development of obesity, diabetes and cardiovascular disease later in life. Emerging evidence suggests that changes in placental amino acid transport directly contribute to altered fetal growth. However, the molecular mechanisms regulating placental amino acid transport are largely unknown. Here we combined small interfering (si) RNA-mediated silencing approaches with protein expression/localization and functional studies in cultured primary human trophoblast cells to test the hypothesis that mammalian target of rapamycin complex 1 (mTORC1) and 2 (mTORC2) regulate amino acid transporters by post-translational mechanisms. Silencing raptor (inhibits mTORC1) or rictor (inhibits mTORC2) markedly decreased basal System A and System L amino acid transport activity but had no effect on growth factor-stimulated amino acid uptake. Simultaneous inhibition of mTORC1 and 2 completely inhibited both basal and growth factor-stimulated amino acid transport activity. In contrast, mTOR inhibition had no effect on serotonin transport. mTORC1 or mTORC2 silencing markedly decreased the plasma membrane expression of specific System A (SNAT2, SLC38A2) and System L (LAT1, SLC7A5) transporter isoforms without affecting global protein expression. In conclusion, mTORC1 and mTORC2 regulate human trophoblast amino acid transporters by modulating the cell surface abundance of specific transporter isoforms. This is the first report showing regulation of amino acid transport by mTORC2. Because placental mTOR activity and amino acid transport are decreased in human intrauterine growth restriction our data are consistent with the possibility that dysregulation of placental mTOR plays an important role in the development of abnormal fetal growth.
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Affiliation(s)
- Fredrick J Rosario
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center San Antonio, Mail Code 7836, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
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Bernardo AS, Faial T, Gardner L, Niakan KK, Ortmann D, Senner CE, Callery EM, Trotter MW, Hemberger M, Smith JC, Bardwell L, Moffett A, Pedersen RA. BRACHYURY and CDX2 mediate BMP-induced differentiation of human and mouse pluripotent stem cells into embryonic and extraembryonic lineages. Cell Stem Cell 2012; 9:144-55. [PMID: 21816365 PMCID: PMC3567433 DOI: 10.1016/j.stem.2011.06.015] [Citation(s) in RCA: 276] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 04/14/2011] [Accepted: 06/30/2011] [Indexed: 11/01/2022]
Abstract
BMP is thought to induce hESC differentiation toward multiple lineages including mesoderm and trophoblast. The BMP-induced trophoblast phenotype is a long-standing paradox in stem cell biology. Here we readdressed BMP function in hESCs and mouse epiblast-derived cells. We found that BMP4 cooperates with FGF2 (via ERK) to induce mesoderm and to inhibit endoderm differentiation. These conditions induced cells with high levels of BRACHYURY (BRA) that coexpressed CDX2. BRA was necessary for and preceded CDX2 expression; both genes were essential for expression not only of mesodermal genes but also of trophoblast-associated genes. Maximal expression of the latter was seen in the absence of FGF but these cells coexpressed mesodermal genes and moreover they differed in cell surface and epigenetic properties from placental trophoblast. We conclude that BMP induces human and mouse pluripotent stem cells primarily to form mesoderm, rather than trophoblast, acting through BRA and CDX2.
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Affiliation(s)
- Andreia S Bernardo
- The Anne McLaren Laboratory for Regenerative Medicine, University of Cambridge, Cambridge CB2 0SZ, UK.
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Moll SJ, Jones CJP, Crocker IP, Baker PN, Heazell AEP. Epidermal growth factor rescues trophoblast apoptosis induced by reactive oxygen species. Apoptosis 2007; 12:1611-22. [PMID: 17573555 DOI: 10.1007/s10495-007-0092-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Pre-eclampsia and intrauterine growth restriction are associated with increased apoptosis of placental villous trophoblast. This may result from placental hypoperfusion, leading to the generation of reactive oxygen species (ROS). Apoptosis can be induced in villous trophoblast following exposure to oxidative stress. Epidermal growth factor (EGF) reduces trophoblast apoptosis resulting from exposure to hypoxia. We hypothesised that exposure to hydrogen peroxide, a potent generator of ROS, would induce apoptosis in term placental villous explants and that this could be reduced by treatment with EGF. Placental explants were taken from normal term pregnancies and exposed to increasing doses of hydrogen peroxide (0-1,000 microM) or to a combination of increasing doses of hydrogen peroxide and EGF (0-100 ng/ml) for either 6 or 48 h. Apoptosis was assessed by TUNEL, proliferation by Ki-67 immunostaining, necrosis by lactate dehydrogenase activity and trophoblast differentiation by human chorionic gonadotrophin (hCG) secretion in conditioned culture media. Immunoperoxidase staining was performed to identify phosphorylated-AKT (p-AKT) and phosphorylated-PI3 kinase (p-PI3k). Exposure to 1,000 microM hydrogen peroxide for 48 h induced apoptosis in placental explants. The increase in TUNEL positive nuclei predominantly localised to syncytiotrophoblast. The amount of apoptosis was reduced to control levels by treatment with 10 and 100 ng/ml EGF. Proliferation of cytotrophoblasts within villous explants was significantly reduced following exposure to 1,000 microM hydrogen peroxide, this was restored to control levels by simultaneous treatment with 10 or 100 ng/ml EGF. Neither exposure to hydrogen peroxide or EGF altered the amount of necrosis. There was increased immunostaining for pPI3K following treatment with EGF. This study shows that apoptosis may be induced in villous trophoblast following exposure to ROS, and demonstrates the anti-apoptotic effect of EGF in trophoblast, the maintenance of which is essential for normal pregnancy.
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Affiliation(s)
- Sarah J Moll
- Division of Human Development, St Mary's Hospital, University of Manchester, Hathersage Road, Manchester M13 0JH, UK
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Ericsson A, Hamark B, Powell TL, Jansson T. Glucose transporter isoform 4 is expressed in the syncytiotrophoblast of first trimester human placenta. Hum Reprod 2005; 20:521-30. [PMID: 15528266 DOI: 10.1093/humrep/deh596] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Placental glucose transport mechanisms in early pregnancy are poorly understood. The aims of this study were to investigate the expression of glucose transporter (GLUT) isoforms 1, 3 and 4 in first trimester villous tissue, to assess the effects of insulin on glucose uptake and compare them with term. METHODS The expression of GLUT isoforms was investigated using immunohistochemistry, Western blot and reverse transcription (RT)-PCR in trophoblast tissue from terminations at 6-13 weeks gestation and term. The effects of insulin (300 ng/ml, 1 h) on glucose uptake were studied in villous fragments. RESULTS In the first trimester, GLUT1 and GLUT3 were present in the microvillous membrane and the cytotrophoblast, and GLUT4 in perinuclear membranes in the cytosol of the syncytiotrophoblast (ST). GLUT4 protein (48 kDa) and mRNA were identified in trophoblast homogenates. Whereas GLUT1 was expressed abundantly in term placenta, the expression of GLUT3 and 4 was markedly lower at term compared with first trimester. Insulin increased glucose uptake by 182% (n=6, P<0.05) in first trimester fragments, but not in term fragments. CONCLUSIONS The insulin-regulatable GLUT4 is expressed in the cytosol of first trimester ST compatible with a role for GLUT4 in placental glucose transport in early pregnancy. The placental expression pattern of GLUT isoforms in early pregnancy is distinct from that later in pregnancy.
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Affiliation(s)
- A Ericsson
- Department of Physiology and Pharmacology, Perinatal Center, Göteborg University, 405 30 Göteborg, Sweden.
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Desoye G, Hartmann M, Jones CJ, Wolf HJ, Kohnen G, Kosanke G, Kaufmann P. Location of insulin receptors in the placenta and its progenitor tissues. Microsc Res Tech 1997; 38:63-75. [PMID: 9260838 DOI: 10.1002/(sici)1097-0029(19970701/15)38:1/2<63::aid-jemt8>3.0.co;2-v] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The insulin receptor gene is constitutively expressed, so the presence of insulin receptor proteins might be expected on all mammalian tissues, with the plasma membrane as the predominant site of receptor location. Results reviewed here indicate that insulin receptors are also present in all placental tissues and the placenta's progenitor tissues and cells, i.e., oocytes, spermatozoa, and preimplantation embryos, in most of the species studied. Receptor densities, however, vary among individual cells and cell types and at various developmental stages. Three aspects deserve emphasis. 1) In human placenta, the insulin receptor distribution pattern is characterized by a spatiotemporal change between first trimester and term. At the beginning of pregnancy, insulin receptors are found predominantly on the maternal side (apical membrane of syncytiotrophoblast, low density on cytotrophoblast); at term, however, they are on the fetal side (lining the fetal vessels). This suggests that, in the first trimester, maternal insulin regulates insulin-dependent processes, whereas, at term, it must be fetal insulin mainly controlling these processes. 2) The majority of insulin receptors is expressed on structures that are currently assumed to drive placental growth, i.e., syncytial sprouts and mesenchymal villi in first-trimester placentas and fetal endothelium at term. Therefore, we hypothesize a growth-promoting function, among others, of insulin on the placenta. 3) At present, no histologic evidence is available to demonstrate insulin receptors in structures commonly associated with receptor-mediated endocytosis. Whether placental insulin receptors are internalized, therefore, awaits clarification.
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Affiliation(s)
- G Desoye
- Department of Obstetrics and Gynecology, University of Graz, Austria
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Watanabe T, Fukaya T, Yajima A, Sasano H. Expression of epidermal growth factor (EGF) family and expression of epidermal growth factor receptor (EGFR) in human chorionic villi. Placenta 1997. [DOI: 10.1016/s0143-4004(05)80159-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Filla MS, Kaul KL. Relative expression of epidermal growth factor receptor in placental cytotrophoblasts and choriocarcinoma cell lines. Placenta 1997; 18:17-27. [PMID: 9032806 DOI: 10.1016/s0143-4004(97)90067-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The role of transforming growth factor-alpha (TGF-alpha)-epidermal growth factor receptor (EGFR) interactions in regulating benign and malignant trophoblast proliferation were examined. Benign cytotrophoblast (CT) demonstrated mitogenic stimulation in response to TGF-alpha; BeWo and JAr choriocarcinoma cell lines failed to respond. EGFR levels in BeWo and JAr were determined by enzyme linked immunoassay (ELISA) to be at least 10-fold higher than those in benign CT. EGFR isolated from BeWo and JAr also demonstrated functional tyrosine kinase activity. Using a combination of immunoperoxidase (IP) and ELISA techniques, choriocarcinoma cells were found to produce significant quantities of TGF-alpha that were comparable with those reported previously by this laboratory for benign CT, and were felt to be stimulating their own proliferation in an autocrine fashion. EGFR blocking and TGF-alpha neutralizing antibodies inhibited JAr proliferation whereas an EGF neutralizing antibody did not. The data presented here and in our previous report indicate that a TGF-alpha-EGFR autocrine loop may regulate normal and malignant CT proliferation. Choriocarcinoma cells may be proliferating at a maximal rate due, in part, to EGFR overexpression and are therefore unable to respond further to exogenous growth factor. Thus, EGFR overexpression may contribute to the uncontrolled proliferation of choriocarcinoma cells in general.
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Affiliation(s)
- M S Filla
- Department of Pathology, Northwestern University, Evanston Hospital, IL 60201, USA
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17
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Kristoffersen EK. Human placental Fc gamma-binding proteins in the maternofetal transfer of IgG. APMIS. SUPPLEMENTUM 1996; 64:5-36. [PMID: 8944053 DOI: 10.1111/j.1600-0463.1996.tb05583.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Annexin II, a member of the annexin family of Ca2+ and phospholipid binding proteins, is present in human placenta. Placental annexin II has low affinity FcR activity, and is present as a heterotetramere on syncytiotrophoblast apical cell membrane extracellular surface. In addition to annexin II, transmembraneous leukocyte FcRIII is present on syncytiotrophoblast apical membrane. Either one, or both molecules may mediate the binding of IgG and thereby facilitate its transport through the syncytiotrophoblast layer. However, the presence of other maternal plasma proteins in syncytiotrophoblasts that are not transported to the human fetus is suggestive of nonspecific fluid phase endocytosis. The MHC class I like FcR, similar to the receptor found in neonatal rodent intestine, FcRn, is present intracellularly in human syncytiotrophoblasts, as is its light chain beta 2-microglobulin. The hFcRn is not detected on the apical plasma membrane. The placental hFcRn co-localizes with IgG in syncytiotrophoblast granules. It is likely that hFcRn binds and transcytoses IgG through the syncytiotrophoblast. Protected transfer of IgG may occur within syncytiotrophoblast endocytotic vesicles prior to release in the villous stroma and subsequent translocation into the lumen of fetal stem vessels by uptake and transport in endothelial caveolae.
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Affiliation(s)
- E K Kristoffersen
- Department of Microbiology and Immunology, Gade Institute, University of Bergen, Norway
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18
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Garcia-Lloret MI, Yui J, Winkler-Lowen B, Guilbert LJ. Epidermal growth factor inhibits cytokine-induced apoptosis of primary human trophoblasts. J Cell Physiol 1996; 167:324-32. [PMID: 8613474 DOI: 10.1002/(sici)1097-4652(199605)167:2<324::aid-jcp17>3.0.co;2-7] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In the placenta, as in other organs, the development and maintenance of the differentiated phenotype depend on a balance between cell proliferation, maturation, and death. We are interested in the mechanisms that regulate the survival and differentiation of placental trophoblasts and have recently demonstrated that the inflammatory cytokines tumor necrosis factor alpha (TNF alpha) and gamma interferon (IFN gamma) act in concert to induce apoptotic cell death in normal cytotrophoblasts in culture. In this report we show that exposure to epidermal growth factor (EGF), a 6,700 dalton polypeptide that is abundantly expressed in maternal and fetal tissues, blocks the in vitro TNF/IFN-induced cytotoxicity of human cytotrophoblasts and syncytiotrophoblasts from normal term placentas. This antagonistic effect is dose-related (10-10 M EGF, half-maximal) and proceeds via the interruption of an early step in the cytokine-induced apoptotic response. These observations suggest a novel role for EGF in normal placental development and indicate that the interplay between EGF, TNF alpha, and IFN gamma may determine the rate of trophoblast growth and renewal during gestation.
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Affiliation(s)
- M I Garcia-Lloret
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Canada
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19
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Bass KE, Morrish D, Roth I, Bhardwaj D, Taylor R, Zhou Y, Fisher SJ. Human cytotrophoblast invasion is up-regulated by epidermal growth factor: evidence that paracrine factors modify this process. Dev Biol 1994; 164:550-61. [PMID: 8045351 DOI: 10.1006/dbio.1994.1223] [Citation(s) in RCA: 156] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Formation of the human placenta requires a subset of cytotrophoblast stem cells to acquire an invasive phenotype. We examined the effect on cytotrophoblast invasiveness of growth factors that control the differentiation of other cells. Exogenous TGF-beta 1, PDGF-AA, PDGF-BB, and TNF-alpha affected neither cell morphology nor the rate of cytotrophoblast invasion in vitro. In contrast, addition of EGF to first trimester cytotrophoblast cultures produced dramatic changes in morphology and a severalfold increase in invasive capacity. The effects of EGF on later gestation cytotrophoblasts, whose invasive capacity is diminished, were much less pronounced. Next we investigated whether cytotrophoblasts themselves produce ligands that interact with the EGF receptor. A radioimmunoassay and a radioreceptor assay failed to detect EGF receptor ligands in cytotrophoblast-conditioned medium. Likewise, by RT-PCR cytotrophoblasts expressed neither EGF nor TGF-alpha mRNA. In contrast, EGF receptor mRNA was expressed and its protein levels remained constant during the experiment. Immunolocalization using F(ab') fragments of an anti-human EGF antibody failed to detect this growth factor in the chorionic villus. We conclude that maternal ligands that interact with the EGF receptor could play an important role by up-regulating trophoblast invasion, particularly during the early stages of pregnancy.
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Affiliation(s)
- K E Bass
- Department of Stomatology, University of California San Francisco 94143
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20
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Desoye G, Hartmann M, Blaschitz A, Dohr G, Hahn T, Kohnen G, Kaufmann P. Insulin receptors in syncytiotrophoblast and fetal endothelium of human placenta. Immunohistochemical evidence for developmental changes in distribution pattern. HISTOCHEMISTRY 1994; 101:277-85. [PMID: 7928411 DOI: 10.1007/bf00315915] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The localisation of insulin receptors (IR) was investigated on cryosections of human non-pathologic first trimester and full term placentae by indirect immunohistochemistry with three different monoclonal antibodies (MABS). In placentae from 6 to 10 weeks postmenstruation (p-m.), only syncytiotrophoblast was stained, predominantly that of mesenchymal villi and syncytial sprouts, which are areas of high proliferative activity. In placentae from 11 to 14 weeks p-m., endothelial cells commenced to react with the IR MABS and the syncytiotrophoblast was less intensely labelled than at weeks 6 to 10 p-m. In term placentae, the microvillous membrane of the syncytiotrophoblast showed only patches of weak immunoreactivity. In contrast, the endothelial cells in the placenta but not in the umbilical cord were strongly stained. The amniotic epithelium in the chorionic plate and fibroblasts in the stroma were conspicuously labelled. The data indicate: (1) the receptor density on villous syncytiotrophoblast decreases and that of fetal endothelium increases' throughout gestation; (2) syncytiotrophoblast of human term placentae expresses a low level per unit area of surface IR; and (3) the majority of IR in human term placentae is located in fetal endothelium. Apart from yet unknown functional effects of maternal and fetal insulin at the placental barrier, the results suggest a growth promoting effect on the trophoblast of maternal insulin in first trimester as well as developmental effects of fetal insulin on the feto-placental vessels at term.
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Affiliation(s)
- G Desoye
- Department of Obstetrics and Gynaecology, Karl-Franzens-University of Graz, Austria
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21
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Affiliation(s)
- G Desoye
- Department of Obstetrics and Gynecology, University of Graz, Austria
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Owens OJ, Leake RE. Epidermal growth factor receptor in normal ovaries and benign ovarian tumours. Eur J Obstet Gynecol Reprod Biol 1992; 47:229-33. [PMID: 1294410 DOI: 10.1016/0028-2243(92)90156-s] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Epidermal growth factor receptor (EGFR) was assayed in 52 women who had normal ovaries removed at hysterectomy and in 30 women with benign ovarian tumours. The histology of each ovary was recorded. A single point screen was performed on all samples and in positive cases a full Scatchard analysis. EGFR was present in 8 of 52 normal ovaries (15.4%) and 3 contained the high-affinity component while 5 had the low affinity component. In the benign ovarian tumour group 4 of 30 tumours (13.3%) had receptor present, one was high affinity and 3 were low affinity in type. We can conclude that EGFR is detectable only at low frequency in normal and benign ovarian tumours.
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Affiliation(s)
- O J Owens
- Department of Biochemistry, Glasgow University, UK
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Stirrat GM, Scott JR. Overview and future perspectives. BAILLIERE'S CLINICAL OBSTETRICS AND GYNAECOLOGY 1992; 6:657-67. [PMID: 1446425 DOI: 10.1016/s0950-3552(05)80016-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- G M Stirrat
- Faculty of Medicine and Professor, University of Bristol, Department of Obstetrics and Gynaecology, St Michael's Hospital, Bristol, UK
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