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Gong S, Gaccioli F, Aye ILMH, Avellino G, Cook E, Lawson ARJ, Harvey LMR, Smith GCS, Charnock-Jones DS. The human placenta exhibits a unique transcriptomic void. Cell Rep 2023; 42:112800. [PMID: 37453066 DOI: 10.1016/j.celrep.2023.112800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 02/08/2023] [Accepted: 06/26/2023] [Indexed: 07/18/2023] Open
Abstract
The human placenta exhibits a unique genomic architecture with an unexpectedly high mutation burden and many uniquely expressed genes. The aim of this study is to identify transcripts that are uniquely absent or depleted in the placenta. Here, we show that 40 of 46 of the other organs have no selectively depleted transcripts and that, of the remaining six, the liver has the largest number, with 26. In contrast, the term placenta has 762 depleted transcripts. Gene Ontology analysis of this depleted set highlighted multiple pathways reflecting known unique elements of placental physiology. For example, transcripts associated with neuronal function are in the depleted set-as expected given the lack of placental innervation. However, this demonstrated overrepresentation of genes involved in mitochondrial function (p = 5.8 × 10-10), including PGC-1α, the master regulator of mitochondrial biogenesis, and genes involved in polyamine metabolism (p = 2.1 × 10-4).
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Affiliation(s)
- Sungsam Gong
- Department of Obstetrics and Gynaecology, NIHR Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, UK; Centre for Trophoblast Research (CTR), Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Francesca Gaccioli
- Department of Obstetrics and Gynaecology, NIHR Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, UK; Centre for Trophoblast Research (CTR), Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Irving L M H Aye
- Department of Obstetrics and Gynaecology, NIHR Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, UK; Centre for Trophoblast Research (CTR), Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Giulia Avellino
- Department of Obstetrics and Gynaecology, NIHR Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, UK; Centre for Trophoblast Research (CTR), Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Emma Cook
- Department of Obstetrics and Gynaecology, NIHR Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, UK
| | | | | | - Gordon C S Smith
- Department of Obstetrics and Gynaecology, NIHR Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, UK; Centre for Trophoblast Research (CTR), Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - D Stephen Charnock-Jones
- Department of Obstetrics and Gynaecology, NIHR Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, UK; Centre for Trophoblast Research (CTR), Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
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Avellino G, Deshmukh R, Rogers SN, Charnock-Jones DS, Smith GCS, Tardito S, Aye ILMH. Physiologically relevant culture medium Plasmax improves human placental trophoblast stem cell function. Am J Physiol Cell Physiol 2023; 324:C878-C885. [PMID: 36878843 PMCID: PMC10069969 DOI: 10.1152/ajpcell.00581.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Human trophoblast cultures provide powerful tools to model key processes of placental development. In vitro trophoblast studies to date have relied on commercial media which contains non-physiological levels of nutrients, and the impact of these conditions on trophoblast metabolism and function is unknown. Here we show that the physiological medium (Plasmaxä) with nutrient and metabolite concentrations recapitulating human plasma improves human trophoblast stem cell (hTSC) proliferation and differentiation compared to standard medium (DMEM-F12). hTSCs cultured in Plasmax-based medium also show altered glycolytic and mitochondrial metabolism, as well as reduced S-adenosylmethionine/S-adenosyl-homosysteine ratio compared to DMEM-F12-based medium. These findings demonstrate the importance of the nutritional environment for phenotyping cultured human trophoblasts.
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Affiliation(s)
- Giulia Avellino
- Department of Obstetrics and Gynaecology, University of Cambridge, NIHR Cambridge Comprehensive Biomedical Research Centre, Cambridge, United Kingdom.,Centre for Trophoblast Research (CTR), Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Ruhi Deshmukh
- Cancer Research UK Beatson Institute, Garscube Estate, Glasgow, United Kingdom
| | - Stephanie N Rogers
- Department of Obstetrics and Gynaecology, University of Cambridge, NIHR Cambridge Comprehensive Biomedical Research Centre, Cambridge, United Kingdom
| | - D Stephen Charnock-Jones
- Department of Obstetrics and Gynaecology, University of Cambridge, NIHR Cambridge Comprehensive Biomedical Research Centre, Cambridge, United Kingdom.,Centre for Trophoblast Research (CTR), Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Gordon C S Smith
- Department of Obstetrics and Gynaecology, University of Cambridge, NIHR Cambridge Comprehensive Biomedical Research Centre, Cambridge, United Kingdom.,Centre for Trophoblast Research (CTR), Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Saverio Tardito
- Cancer Research UK Beatson Institute, Garscube Estate, Glasgow, United Kingdom.,Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Irving L M H Aye
- Department of Obstetrics and Gynaecology, University of Cambridge, NIHR Cambridge Comprehensive Biomedical Research Centre, Cambridge, United Kingdom.,Centre for Trophoblast Research (CTR), Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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Tarry-Adkins JL, Robinson IG, Reynolds RM, Aye ILMH, Charnock-Jones DS, Jenkins B, Koulmann A, Ozanne SE, Aiken CE. Impact of Metformin Treatment on Human Placental Energy Production and Oxidative Stress. Front Cell Dev Biol 2022; 10:935403. [PMID: 35784487 PMCID: PMC9247405 DOI: 10.3389/fcell.2022.935403] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 05/20/2022] [Indexed: 02/02/2023] Open
Abstract
Metformin is increasingly prescribed in pregnancy, with beneficial maternal effects. However, it is not known how metformin-treatment impacts metabolism and energy production in the developing feto-placental unit. We assessed the human placental response to metformin using both in vivo and in vitro treated samples. trophoblasts were derived from placentas collected from non-laboured Caesarean deliveries at term, then treated in vitro with metformin (0.01 mM, 0.1 mM or vehicle). Metformin-concentrations were measured using liquid-chromatography mass-spectrometry. Oxygen consumption in cultured-trophoblasts was measured using a Seahorse-XF Mito Stress Test. Markers of oxidative-stress were assayed using qRT-PCR. Metformin-transporter mRNA and protein-levels were determined by quantitative RT-PCR and Western-blotting respectively. Metformin concentrations were also measured in sample trios (maternal plasma/fetal plasma/placental tissue) from pregnancies exposed to metformin on clinical-grounds. Maternal and fetal metformin concentrations in vivo were highly correlated over a range of concentrations (R2 = 0.76, p < 0.001; average fetal:maternal ratio 1.5; range 0.8-2.1). Basal respiration in trophoblasts was reduced by metformin treatment (0.01 mM metformin; p < 0.05, 0.1 mM metformin; p < 0.001). Mitochondrial-dependent ATP production and proton leak were reduced after treatment with metformin (p < 0.001). Oxidative stress markers were significantly reduced in primary-trophoblast-cultures following treatment with metformin. There is a close linear relationship between placental, fetal, and maternal metformin concentrations. Primary-trophoblast cultures exposed to clinically-relevant metformin concentrations have reduced mitochondrial-respiration, mitochondrial-dependent ATP-production, and reduced markers of oxidative-stress. Given the crucial role of placental energy-production in supporting fetal growth and well-being during pregnancy, the implications of these findings are concerning for intrauterine fetal growth and longer-term metabolic programming in metformin-exposed pregnancies.
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Affiliation(s)
- Jane L. Tarry-Adkins
- Department of Obstetrics and Gynaecology, The Rosie Hospital and NIHR Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, United Kingdom
| | - India G. Robinson
- Department of Obstetrics and Gynaecology, The Rosie Hospital and NIHR Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, United Kingdom
| | - Rebecca M. Reynolds
- Queen’s Medical Research Institute, Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Irving L. M. H. Aye
- Department of Obstetrics and Gynaecology, The Rosie Hospital and NIHR Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, United Kingdom,Centre for Trophoblast Research, University of Cambridge, Cambridge, United Kingdom
| | - D. Stephen Charnock-Jones
- Department of Obstetrics and Gynaecology, The Rosie Hospital and NIHR Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, United Kingdom,Centre for Trophoblast Research, University of Cambridge, Cambridge, United Kingdom
| | - Benjamin Jenkins
- Wellcome-MRC Institute of Metabolic Science and Medical Research Council Metabolic Diseases Unit, Addenbrooke’s Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Albert Koulmann
- Wellcome-MRC Institute of Metabolic Science and Medical Research Council Metabolic Diseases Unit, Addenbrooke’s Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Susan E. Ozanne
- Wellcome-MRC Institute of Metabolic Science and Medical Research Council Metabolic Diseases Unit, Addenbrooke’s Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Catherine E. Aiken
- Department of Obstetrics and Gynaecology, The Rosie Hospital and NIHR Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, United Kingdom,Centre for Trophoblast Research, University of Cambridge, Cambridge, United Kingdom,Wellcome-MRC Institute of Metabolic Science and Medical Research Council Metabolic Diseases Unit, Addenbrooke’s Hospital, University of Cambridge, Cambridge, United Kingdom,*Correspondence: Catherine E. Aiken,
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Aye ILMH, Rosario FJ, Kramer A, Kristiansen O, Michelsen TM, Powell TL, Jansson T. Insulin Increases Adipose Adiponectin in Pregnancy by Inhibiting Ubiquitination and Degradation: Impact of Obesity. J Clin Endocrinol Metab 2022; 107:53-66. [PMID: 34519830 PMCID: PMC8684469 DOI: 10.1210/clinem/dgab680] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Indexed: 12/12/2022]
Abstract
CONTEXT Circulating adiponectin levels are decreased in pregnant women with obesity or gestational diabetes, and this is believed to contribute to the insulin resistance and increased risk of fetal overgrowth associated with these conditions. However, the molecular mechanisms regulating adiponectin secretion from maternal adipose tissues in pregnancy are poorly understood. OBJECTIVE We tested the hypothesis that obesity in pregnancy is associated with adipose tissue insulin resistance and increased adiponectin ubiquitination and degradation, caused by inflammation and endoplasmic reticulum (ER) stress. METHODS Visceral adipose tissues were collected from lean and obese pregnant humans and mice. Total and ubiquitinated adiponectin, and markers of inflammation, ER stress, and insulin resistance were examined in adipose tissues. The role of insulin, inflammation, and ER stress in mediating adiponectin ubiquitination and degradation was examined using 3T3L-1 adipocytes. RESULTS Obesity in pregnancy is associated with adipose tissue inflammation, ER stress, insulin resistance, increased adiponectin ubiquitination, and decreased total abundance of adiponectin. Adiponectin ubiquitination was increased in visceral fat of obese pregnant women as compared to lean pregnant women. We further observed that insulin prevents, whereas ER stress and inflammation promote, adiponectin ubiquitination and degradation in differentiated 3T3-L1 adipocytes. CONCLUSION We have identified adiponectin ubiquitination as a key mechanism by which obesity diminishes adiponectin secretion in pregnancy. This information will help us better understand the mechanisms controlling maternal insulin resistance and fetal growth in pregnancy and may provide a foundation for the development of strategies aimed at improving adiponectin production in pregnant women with obesity or gestational diabetes.
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Affiliation(s)
- Irving L M H Aye
- Department of Obstetrics & Gynaecology, and Centre for Trophoblast Research, University of Cambridge, Cambridge, UK
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Correspondence: Irving L. M. H. Aye, PhD, Department of Obstetrics & Gynaecology, University of Cambridge, The Rosie Hospital, Robinson Way, Cambridge CB2 0SW, UK.
| | - Fredrick J Rosario
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Anita Kramer
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Oddrun Kristiansen
- Department of Obstetrics, Division of Obstetrics and Gynecology, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Trond M Michelsen
- Department of Obstetrics, Division of Obstetrics and Gynecology, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Theresa L Powell
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Department of Pediatrics, Section of Neonatology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Thomas Jansson
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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Aye ILMH, Moraitis AA, Stanislaus D, Charnock-Jones DS, Smith GCS. Retosiban Prevents Stretch-Induced Human Myometrial Contractility and Delays Labor in Cynomolgus Monkeys. J Clin Endocrinol Metab 2018; 103:1056-1067. [PMID: 29293998 PMCID: PMC5868409 DOI: 10.1210/jc.2017-02195] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 12/20/2017] [Indexed: 12/13/2022]
Abstract
Context Stretch of the myometrium promotes its contractility and is believed to contribute to the control of parturition at term and to the increased risk of preterm birth in multiple pregnancies. Objective To determine the effects of the putative oxytocin receptor (OTR) inverse agonist retosiban on (1) the contractility of human myometrial explants and (2) labor in nonhuman primates. Design Human myometrial biopsies were obtained at planned term cesarean, and explants were exposed to stretch in the presence and absence of a range of drugs, including retosiban. The in vivo effects of retosiban were determined in cynomolgus monkeys. Results Prolonged mechanical stretch promoted myometrial extracellular signal-regulated kinase (ERK)1/2 phosphorylation. Moreover, stretch-induced stimulation of myometrial contractility was prevented by ERK1/2 inhibitors. Retosiban (10 nM) prevented stretch-induced stimulation of myometrial contractility and phosphorylation of ERK1/2. Moreover, the inhibitory effect of retosiban on stretch-induced ERK1/2 phosphorylation was prevented by coincubation with a 100-fold excess of a peptide OTR antagonist, atosiban. Compared with vehicle-treated cynomolgus monkeys, treatment with oral retosiban (100 to 150 days of gestational age) reduced the risk of spontaneous delivery (hazard ratio = 0.07, 95% confidence interval 0.01 to 0.60, P = 0.015). Conclusions The OTR acts as a uterine mechanosensor, whereby stretch increases myometrial contractility through agonist-free activation of the OTR. Retosiban prevents this through inverse agonism of the OTR and, in vivo, reduced the likelihood of spontaneous labor in nonhuman primates. We hypothesize that retosiban may be an effective preventative treatment of preterm birth in high-risk multiple pregnancies, an area of unmet clinical need.
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Affiliation(s)
- Irving L M H Aye
- Department of Obstetrics and Gynaecology, University of Cambridge, National Institute for Health Research, Cambridge Comprehensive Biomedical Research Centre, Cambridge, United Kingdom
| | - Alexandros A Moraitis
- Department of Obstetrics and Gynaecology, University of Cambridge, National Institute for Health Research, Cambridge Comprehensive Biomedical Research Centre, Cambridge, United Kingdom
| | - Dinesh Stanislaus
- Department of Reproductive Toxicology, GlaxoSmithKline, Philadelphia Navy Yard, Philadelphia, Pennsylvania
| | - D Stephen Charnock-Jones
- Department of Obstetrics and Gynaecology, University of Cambridge, National Institute for Health Research, Cambridge Comprehensive Biomedical Research Centre, Cambridge, United Kingdom
| | - Gordon C S Smith
- Department of Obstetrics and Gynaecology, University of Cambridge, National Institute for Health Research, Cambridge Comprehensive Biomedical Research Centre, Cambridge, United Kingdom
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Gaccioli F, Aye ILMH, Sovio U, Charnock-Jones DS, Smith GCS. Screening for fetal growth restriction using fetal biometry combined with maternal biomarkers. Am J Obstet Gynecol 2018; 218:S725-S737. [PMID: 29275822 DOI: 10.1016/j.ajog.2017.12.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/24/2017] [Accepted: 12/01/2017] [Indexed: 12/31/2022]
Abstract
Fetal growth restriction is a major determinant of perinatal morbidity and mortality. Screening for fetal growth restriction is a key element of prenatal care but it is recognized to be problematic. Screening using clinical risk assessment and targeting ultrasound to high-risk women is the standard of care in the United States and United Kingdom, but the approach is known to have low sensitivity. Systematic reviews of randomized controlled trials do not demonstrate any benefit from universal ultrasound screening for fetal growth restriction in the third trimester, but the evidence base is not strong. Implementation of universal ultrasound screening in low-risk women in France failed to reduce the risk of complications among small-for-gestational-age infants but did appear to cause iatrogenic harm to false positives. One strategy to making progress is to improve screening by developing more sensitive and specific tests with the key goal of differentiating between healthy small fetuses and those that are small through fetal growth restriction. As abnormal placentation is thought to be the major cause of fetal growth restriction, one approach is to combine fetal biometry with an indicator of placental dysfunction. In the past, these indicators were generally ultrasonic measurements, such as Doppler flow velocimetry of the uteroplacental circulation. However, another promising approach is to combine ultrasonic suspicion of small-for-gestational-age infant with a blood test indicating placental dysfunction. Thus far, much of the research on maternal serum biomarkers for fetal growth restriction has involved the secondary analysis of tests performed for other indications, such as fetal aneuploidies. An exemplar of this is pregnancy-associated plasma protein A. This blood test is performed primarily to assess the risk of Down syndrome, but women with low first-trimester levels are now serially scanned in later pregnancy due to associations with placental causes of stillbirth, including fetal growth restriction. The development of "omic" technologies presents a huge opportunity to identify novel biomarkers for fetal growth restriction. The hope is that when such markers are measured alongside ultrasonic fetal biometry, the combination would have strong predictive power for fetal growth restriction and its related complications. However, a series of important methodological considerations in assessing the diagnostic effectiveness of new tests will have to be addressed. The challenge thereafter will be to identify novel disease-modifying interventions, which are the essential partner to an effective screening test to achieve clinically effective population-based screening.
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Affiliation(s)
- Francesca Gaccioli
- Department of Obstetrics and Gynaecology, National Institute for Health Research Cambridge Comprehensive Biomedical Research Center, and Center for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Irving L M H Aye
- Department of Obstetrics and Gynaecology, National Institute for Health Research Cambridge Comprehensive Biomedical Research Center, and Center for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Ulla Sovio
- Department of Obstetrics and Gynaecology, National Institute for Health Research Cambridge Comprehensive Biomedical Research Center, and Center for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - D Stephen Charnock-Jones
- Department of Obstetrics and Gynaecology, National Institute for Health Research Cambridge Comprehensive Biomedical Research Center, and Center for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Gordon C S Smith
- Department of Obstetrics and Gynaecology, National Institute for Health Research Cambridge Comprehensive Biomedical Research Center, and Center for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.
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Abstract
Maternal obesity and gestational diabetes mellitus (GDM) increase the risk of delivering infants that are large for gestational age with greater adiposity, who are prone to the development of metabolic disease in childhood and beyond. These maternal conditions are also associated with increased levels of the proinflammatory cytokine TNF-α in maternal tissues and the placenta. Recent evidence suggests that changes in placental amino acid transport contribute to altered fetal growth. TNF-α was previously shown to stimulate System A amino acid transport in primary human trophoblasts (PHTs), however the molecular mechanisms remain unknown. In this study, we tested the hypothesis that TNF-α regulates amino acid uptake in cultured PHTs by a mitogen-activated protein kinase (MAPK)-dependent mechanism. Treatment of PHTs with TNF-α significantly increased System A amino acid transport, as well as Erk and p38 MAPK signaling. Pharmacological antagonism of p38, but not Erk MAPK activity, inhibited TNF-α stimulated System A activity. Silencing of p38 MAPK using siRNA transfections prevented TNF-α stimulated System A transport in PHTs. TNF-α significantly increased the protein expression of System A transporters SNAT1 and SNAT2, but did not affect their mRNA expression. The effects of TNF-α on SNAT1 and SNAT2 protein expression were reversed by p38 MAPK siRNA silencing. In conclusion, TNF-α regulates System A activity through increased SNAT1 and SNAT2 transporter protein expression in PHTs. These findings suggest that p38 MAPK may represent a critical mechanistic link between elevated proinflammatory cytokines and increased placental amino acid transport in obese and GDM pregnancies associated with fetal overgrowth.
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Affiliation(s)
- Irving L M H Aye
- 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 Section of Neonatology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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Gaccioli F, Aye ILMH, Roos S, Lager S, Ramirez VI, Kanai Y, Powell TL, Jansson T. Expression and functional characterisation of System L amino acid transporters in the human term placenta. Reprod Biol Endocrinol 2015; 13:57. [PMID: 26050671 PMCID: PMC4462079 DOI: 10.1186/s12958-015-0054-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Accepted: 05/28/2015] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND System L transporters LAT1 (SLC7A5) and LAT2 (SLC7A8) mediate the uptake of large, neutral amino acids in the human placenta. Many System L substrates are essential amino acids, thus representing crucial nutrients for the growing fetus. Both LAT isoforms are expressed in the human placenta, but the relative contribution of LAT1 and LAT2 to placental System L transport and their subcellular localisation are not well established. Moreover, the influence of maternal body mass index (BMI) on placental System L amino acid transport is poorly understood. Therefore the aims of this study were to determine: i) the relative contribution of the LAT isoforms to System L transport activity in primary human trophoblast (PHT) cells isolated from term placenta; ii) the subcellular localisation of LAT transporters in human placenta; and iii) placental expression and activity of System L transporters in response to maternal overweight/obesity. METHODS System L mediated leucine uptake was measured in PHT cells after treatment with si-RNA targeting LAT1 and/or LAT2. The localisation of LAT isoforms was studied in isolated microvillous plasma membranes (MVM) and basal membranes (BM) by Western blot analysis. Results were confirmed by immunohistochemistry in sections of human term placenta. Expression and activity System L transporters was measured in isolated MVM from women with varying pre-pregnancy BMI. RESULTS Both LAT1 and LAT2 isoforms contribute to System L transport activity in primary trophoblast cells from human term placenta. LAT1 and LAT2 transporters are highly expressed in the MVM of the syncytiotrophoblast layer at term. LAT2 is also localised in the basal membrane and in endothelial cells lining the fetal capillaries. Measurements in isolated MVM vesicles indicate that System L transporter expression and activity is not influenced by maternal BMI. CONCLUSIONS LAT1 and LAT2 are present and functional in the syncytiotrophoblast MVM, whereas LAT2 is also expressed in the BM and in the fetal capillary endothelium. In contrast to placental System A and beta amino acid transporters, MVM System L activity is unaffected by maternal overweight/obesity.
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Affiliation(s)
- Francesca Gaccioli
- Department of Obstetrics and Gynaecology, University of Cambridge, Cambridge, UK.
| | - Irving L M H Aye
- Division of Basic Reproductive Sciences, Department of Obstetrics and Gynaecology, University of Colorado Denver Anschutz Medical Campus, Aurora, Denver, CO, USA.
| | - Sara Roos
- Institute of Biomedicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
| | - Susanne Lager
- Department of Obstetrics and Gynaecology, University of Cambridge, Cambridge, UK.
| | - Vanessa I Ramirez
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, TX, USA.
| | - Yoshikatsu Kanai
- Division of Bio-System Pharmacology, Department of Pharmacology, Osaka University Graduate School of Medicine, Osaka, Japan.
| | - Theresa L Powell
- Section of Neonatology, Department of Pediatrics, University of Colorado Denver Anschutz Medical Campus, Aurora, Denver, CO, USA.
| | - Thomas Jansson
- Division of Basic Reproductive Sciences, Department of Obstetrics and Gynaecology, University of Colorado Denver Anschutz Medical Campus, Aurora, Denver, CO, USA.
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Abstract
BACKGROUND The prevalence of maternal obesity is rising rapidly worldwide and constitutes a major obstetric problem, increasing mortality and morbidity in both mother and offspring. Obese women are predisposed to pregnancy complications such as gestational diabetes mellitus (GDM), and children of obese mothers are more likely to develop cardiovascular and metabolic disease in later life. Maternal obesity and GDM may be associated with a state of chronic, low-grade inflammation termed "metainflammation", as opposed to an acute inflammatory response. This inflammatory environment may be one mechanism by which offspring of obese women are programmed to develop adult disorders. METHODS Herein we review the evidence that maternal obesity and GDM are associated with changes in the maternal, fetal and placental inflammatory profile. RESULTS Maternal inflammation in obesity and GDM may not always be associated with fetal inflammation. CONCLUSION We propose that the placenta 'senses' and adapts to the maternal inflammatory environment, and plays a central role as both a target and producer of inflammatory mediators. In this manner, maternal obesity and GDM may indirectly program the fetus for later disease by influencing placental function.
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Affiliation(s)
- P Pantham
- Department of Pediatrics, Section of Neonatology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
| | - I L M H Aye
- Department of Obstetrics & Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - T L Powell
- Department of Pediatrics, Section of Neonatology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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Lager S, Aye ILMH, Gaccioli F, Ramirez VI, Jansson T, Powell TL. Labor inhibits placental mechanistic target of rapamycin complex 1 signaling. Placenta 2014; 35:1007-12. [PMID: 25454472 DOI: 10.1016/j.placenta.2014.10.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 10/08/2014] [Accepted: 10/10/2014] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Labor induces a myriad of changes in placental gene expression. These changes may represent a physiological adaptation inhibiting placental cellular processes associated with a high demand for oxygen and energy (e.g., protein synthesis and active transport) thereby promoting oxygen and glucose transfer to the fetus. We hypothesized that mechanistic target of rapamycin complex 1 (mTORC1) signaling, a positive regulator of trophoblast protein synthesis and amino acid transport, is inhibited by labor. METHODS Placental tissue was collected from healthy, term pregnancies (n = 15 no-labor; n = 12 labor). Activation of Caspase-1, IRS1/Akt, STAT, mTOR, and inflammatory signaling pathways was determined by Western blot. NFĸB p65 and PPARγ DNA binding activity was measured in isolated nuclei. RESULTS Labor increased Caspase-1 activation and mTOR complex 2 signaling, as measured by phosphorylation of Akt (S473). However, mTORC1 signaling was inhibited in response to labor as evidenced by decreased phosphorylation of mTOR (S2448) and 4EBP1 (T37/46 and T70). Labor also decreased NFĸB and PPARγ DNA binding activity, while having no effect on IRS1 or STAT signaling pathway. DISCUSSION AND CONCLUSION Several placental signaling pathways are affected by labor, which has implications for experimental design in studies of placental signaling. Inhibition of placental mTORC1 signaling in response to labor may serve to down-regulate protein synthesis and amino acid transport, processes that account for a large share of placental oxygen and glucose consumption. We speculate that this response preserves glucose and oxygen for transfer to the fetus during the stressful events of labor.
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Affiliation(s)
- S Lager
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, TX 78229, USA.
| | - I L M H Aye
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - F Gaccioli
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - V I Ramirez
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - T Jansson
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - T L Powell
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, TX 78229, USA
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Aye ILMH, Lager S, Ramirez VI, Gaccioli F, Dudley DJ, Jansson T, Powell TL. Increasing maternal body mass index is associated with systemic inflammation in the mother and the activation of distinct placental inflammatory pathways. Biol Reprod 2014; 90:129. [PMID: 24759787 DOI: 10.1095/biolreprod.113.116186] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Obese pregnant women have increased levels of proinflammatory cytokines in maternal circulation and placental tissues. However, the pathways contributing to placental inflammation in obesity are largely unknown. We tested the hypothesis that maternal body mass index (BMI) was associated with elevated proinflammatory cytokines in maternal and fetal circulations and increased activation of placental inflammatory pathways. A total of 60 women of varying pre-/early pregnancy BMI, undergoing delivery by Cesarean section at term, were studied. Maternal and fetal (cord) plasma were collected for analysis of insulin, leptin, IL-1beta, IL-6, IL-8, monocyte chemoattractant protein (MCP) 1, and TNFalpha by multiplex ELISA. Activation of the inflammatory pathways in the placenta was investigated by measuring the phosphorylated and total protein expression of p38-mitogen-activated protein kinase (MAPK), c-Jun-N-terminal kinase (JNK)-MAPK, signal transducer-activated transcription factor (STAT) 3, caspase-1, IL-1beta, IkappaB-alpha protein, and p65 DNA-binding activity. To determine the link between activated placental inflammatory pathways and elevated maternal cytokines, cultured primary human trophoblast (PHT) cells were treated with physiological concentrations of insulin, MCP-1, and TNFalpha, and inflammatory signaling analyzed by Western blot. Maternal BMI was positively correlated with maternal insulin, leptin, MCP-1, and TNFalpha, whereas only fetal leptin was increased with BMI. Placental phosphorylation of p38-MAPK and STAT3, and the expression of IL-1beta protein, were increased with maternal BMI; phosphorylation of p38-MAPK was also correlated with birth weight. In contrast, placental NFkappaB, JNK and caspase-1 signaling, and fetal cytokine levels were unaffected by maternal BMI. In PHT cells, p38-MAPK was activated by MCP-1 and TNFalpha, whereas STAT3 phosphorylation was increased following TNFalpha treatment. Maternal BMI is associated with elevated maternal cytokines and activation of placental p38-MAPK and STAT3 inflammatory pathways, without changes in fetal systemic inflammatory profile. Activation of p38-MAPK by MCP-1 and TNFalpha, and STAT3 by TNFalpha, suggests a link between elevated proinflammatory cytokines in maternal plasma and activation of placental inflammatory pathways. We suggest that inflammatory processes associated with elevated maternal BMI may influence fetal growth by altering placental function.
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Affiliation(s)
- Irving L M H Aye
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas
| | - Susanne Lager
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas
| | - Vanessa I Ramirez
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas
| | - Francesca Gaccioli
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas
| | - Donald J Dudley
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas
| | - Thomas Jansson
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, 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, Texas
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Aye ILMH, Gao X, Weintraub ST, Jansson T, Powell TL. Adiponectin inhibits insulin function in primary trophoblasts by PPARα-mediated ceramide synthesis. Mol Endocrinol 2014; 28:512-24. [PMID: 24606127 DOI: 10.1210/me.2013-1401] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Maternal adiponectin (ADN) levels are inversely correlated with birth weight, and ADN infusion in pregnant mice down-regulates placental nutrient transporters and decreases fetal growth. In contrast to the insulin-sensitizing effects in adipose tissue and muscle, ADN inhibits insulin signaling in the placenta. However, the molecular mechanisms involved are unknown. We hypothesized that ADN inhibits insulin signaling and insulin-stimulated amino acid transport in primary human trophoblasts by peroxisome proliferator-activated receptor-α (PPARα)-mediated ceramide synthesis. Primary human term trophoblast cells were treated with ADN and/or insulin. ADN increased the phosphorylation of p38 MAPK and PPARα. ADN inhibited insulin signaling and insulin-stimulated amino acid transport. This effect was dependent on PPARα, because activation of PPARα with an agonist (GW7647) inhibited insulin signaling and function, whereas PPARα-small interfering RNA reversed the effects of ADN on the insulin response. ADN increased ceramide synthase expression and stimulated ceramide production. C2-ceramide inhibited insulin signaling and function, whereas inhibition of ceramide synthase (with Fumonisin B1) reversed the effects of ADN on insulin signaling and amino acid transport. These findings are consistent with the model that maternal ADN limits fetal growth mediated by activation of placental PPARα and ceramide synthesis, which inhibits placental insulin signaling and amino acid transport, resulting in reduced fetal nutrient availability.
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Affiliation(s)
- Irving L M H Aye
- Center for Pregnancy and Newborn Research (I.L.M.H.A., T.J., T.L.P.), Department of Obstetrics and Gynecology, and Department of Biochemistry (X.G., S.T.W.), University of Texas Health Science Center San Antonio, Texas 78229
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13
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Aye ILMH, Jansson T, Powell TL. Interleukin-1β inhibits insulin signaling and prevents insulin-stimulated system A amino acid transport in primary human trophoblasts. Mol Cell Endocrinol 2013; 381:46-55. [PMID: 23891856 PMCID: PMC3795822 DOI: 10.1016/j.mce.2013.07.013] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 06/13/2013] [Accepted: 07/15/2013] [Indexed: 02/08/2023]
Abstract
Interleukin-1β (IL-1β) promotes insulin resistance in tissues such as liver and skeletal muscle; however the influence of IL-1β on placental insulin signaling is unknown. We recently reported increased IL-1β protein expression in placentas of obese mothers, which could contribute to insulin resistance. In this study, we tested the hypothesis that IL-1β inhibits insulin signaling and prevents insulin-stimulated amino acid transport in cultured primary human trophoblast (PHT) cells. Cultured trophoblasts isolated from term placentas were treated with physiological concentrations of IL-1β (10pg/ml) for 24h. IL-1β increased the phosphorylation of insulin receptor substrate-1 (IRS-1) at Ser307 (inhibitory) and decreased total IRS-1 protein abundance but did not affect insulin receptor β expression. Furthermore, IL-1β inhibited insulin-stimulated phosphorylation of IRS-1 (Tyr612, activation site) and Akt (Thr308) and prevented insulin-stimulated increase in PI3K/p85 and Grb2 protein expression. IL-1β alone stimulated cRaf (Ser338), MEK (Ser221) and Erk1/2 (Thr202/Tyr204) phosphorylation. The inflammatory pathways nuclear factor kappa B and c-Jun N-terminal kinase, which are involved in insulin resistance, were also activated by IL-1β treatment. Moreover, IL-1β inhibited insulin-stimulated System A, but not System L amino acid uptake, indicating functional impairment of insulin signaling. In conclusion, IL-1β inhibited the insulin signaling pathway by inhibiting IRS-1 signaling and prevented insulin-stimulated System A transport, thereby promoting insulin resistance in cultured PHT cells. These findings indicate that conditions which lead to increased systemic maternal or placental IL-1β levels may attenuate the effects of maternal insulin on placental function and consequently fetal growth.
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Affiliation(s)
- Irving L M H Aye
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
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Aye ILMH, Powell TL, Jansson T. Review: Adiponectin--the missing link between maternal adiposity, placental transport and fetal growth? Placenta 2012; 34 Suppl:S40-5. [PMID: 23245987 DOI: 10.1016/j.placenta.2012.11.024] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 11/10/2012] [Accepted: 11/15/2012] [Indexed: 11/29/2022]
Abstract
Adiponectin has well-established insulin-sensitizing effects in non-pregnant individuals. Pregnant women who are obese or have gestational diabetes typically have low circulating levels of adiponectin, which is associated with increased fetal growth. Lean women, on the other hand, have high circulating levels of adiponectin. As a result, maternal serum adiponectin is inversely correlated to fetal growth across the full range of birth weights, suggesting that maternal adiponectin may limit fetal growth. In the mother, adiponectin is predicted to promote insulin sensitivity and stimulate glucose uptake in maternal skeletal muscle thereby reducing nutrient availability for placental transfer. Adiponectin prevents insulin-stimulated amino acid uptake in cultured primary human trophoblast cells by modulating insulin receptor substrate phosphorylation. Furthermore, chronic administration of adiponectin to pregnant mice inhibits placental insulin and mammalian target of rapamycin complex 1 (mTORC1) signaling, down-regulates the activity and expression of key placental nutrient transporters and decreases fetal growth. Preliminary findings indicate that adiponectin binds to the adiponectin receptor-2 on the trophoblast cell and activates p38 MAPK and PPAR-α, which inhibits the insulin/IGF-1 signaling pathway. In contrast to maternal adiponectin, recent reports suggest that fetal adiponectin may promote expansion of adipose tissue and stimulate fetal growth. Regulation of placental function by adiponectin constitutes a novel physiological mechanism by which the endocrine functions of maternal adipose tissue influence fetal growth. These findings may help us better understand the factors determining birth weight in normal pregnancies and in pregnancy complications associated with altered maternal adiponectin levels such as obesity and gestational diabetes.
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Affiliation(s)
- I L M H Aye
- 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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15
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Abstract
Nutrient-sensing signaling pathways regulate cell metabolism and growth in response to altered nutrient levels and growth factor signaling. Because trophoblast cell metabolism and associated signaling influence fetal nutrient availability, trophoblast nutrient sensors may have a unique role in regulating fetal growth. We review data in support of a role for mammalian target of rapamycin complex 1 (mTORC1) in placental nutrient-sensing. Placental insulin/IGF-I signaling and fetal levels of oxygen, glucose and amino acids (AAs) are altered in pregnancy complications such as intrauterine growth restriction, and all these factors are well-established upstream regulators of mTORC1. Furthermore, mTORC1 is a positive regulator of placental AA transporters, suggesting that trophoblast mTORC1 modulates AA transfer across the placenta. In addition, placental mTORC1 signaling is also known to be modulated in pregnancy complications associated with altered fetal growth and in animal models in which maternal nutrient availability has been altered experimentally. Recently, significant progress has been made in identifying the molecular mechanisms by which mTORC1 senses AAs, a process requiring shuttling of mTOR to late endosomal and lysosomal compartments (LELs). We recently identified members of the proton-assisted amino acid transporter (PAT/SLC36) family as critical components of the AA-sensing system or 'nutrisome' that regulates mTORC1 on LEL membranes, placing AA transporters and their subcellular regulation both upstream and downstream of mTORC1-driven processes. We propose a model in which placental mTORC1 signaling constitutes a critical link between maternal nutrient availability and fetal growth, thereby influencing the long-term health of the fetus.
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Affiliation(s)
- T Jansson
- Center for Pregnancy and Newborn Research, Department of OB/GYN, University of Texas Health Science Center, Mail Code 7836, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
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Singh AT, Dharmarajan A, Aye ILMH, Keelan JA. Ceramide biosynthesis and metabolism in trophoblast syncytialization. Mol Cell Endocrinol 2012; 362:48-59. [PMID: 22652149 DOI: 10.1016/j.mce.2012.05.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Revised: 05/02/2012] [Accepted: 05/18/2012] [Indexed: 02/02/2023]
Abstract
Sphingolipid mediators such as ceramide are pleiotropic regulators of cellular growth, differentiation and apoptosis. We investigated the role of ceramide biosynthesis, metabolism and actions in term human cytotrophoblasts syncytialized over 7 days in culture. Intracellular C16 ceramide levels increased modestly after 3 days in culture, then declined. Ceramidase was present at particularly high levels in syncytialized trophoblasts; inhibition of ceramidase reduced the degree of cell fusion. Exposure to short chain C8 ceramide or aSMase enhanced secretion of the differentiation marker hCG without affecting fusion or cell viability. In contrast, pharmacological inhibition of ceramidase reduced the extent of fusion. Inhibition of the ceramide-responsive JNK and PP2A pathways did not abolish the effects of ceramide, and JNK phosphorylation was unresponsive to ceramide; however, ceramide significantly inhibited phosphorylation of Akt. This study suggests that changes in ceramide biosynthesis and metabolism play a differential role in the biochemical and morphological features of trophoblast differentiation.
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Affiliation(s)
- Ambika T Singh
- School of Women's and Infant's Health, Dentistry and Health Sciences, The University of Western Australia, Perth, Australia
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17
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Aye ILMH, Waddell BJ, Mark PJ, Keelan JA. Oxysterols exert proinflammatory effects in placental trophoblasts via TLR4-dependent, cholesterol-sensitive activation of NF-κB. Mol Hum Reprod 2012; 18:341-53. [PMID: 22238372 DOI: 10.1093/molehr/gas001] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Oxidized cholesterol metabolites (oxysterols) promote inflammation in a variety of cell types and are thought to be involved in a number of disease pathologies. Oxysterol concentrations are increased in pregnancy, together with systemic oxidative stress and inflammation. We tested the hypothesis that oxysterols 25-hydroxycholesterol (25-OHC) and 7-ketocholesterol (7-ketoC) promote placental trophoblast inflammation, and determined the mechanisms involved. Treatment of primary trophoblasts in culture with 25-OHC and 7-ketoC increased the production of proinflammatory cytokines (interleukin-6, macrophage inflammatory protein-1β and tumour necrosis factor-α) in a concentration-dependent fashion. Inhibition of TLR4 activation using selective inhibitors of TLR4 complex formation (OxPAPC) or signalling transmission (CLI095) prevented lipopolysaccharide (LPS)- and oxysterol-induced inflammatory cytokine production. Pretreatment of trophoblasts with selective inhibitors of I-kB kinase activity (parthenolide and TPCA-1) reduced oxysterol- and LPS-stimulated inflammatory responses, consistent with the involvement of the nuclear factor kappa B (NF-κB) pathway downstream of TLR4 signalling. Both oxysterols also increased the phosphorylation and nuclear localization of NF-κB subunit p65/RelA. Oxysterols are also known to activate liver X receptors (LXRs) which can inhibit inflammatory signalling, either directly or indirectly via membrane cholesterol reduction. Treatment with the LXR agonist, T0901317, exerted significant anti-inflammatory effects, reducing LPS- and oxysterol-driven cytokine production. Treatment with methyl-β-cyclodextrin to deplete membrane microdomain cholesterol and thereby disrupt TLR4 signalling, similarly abrogated their effects. Together, these findings indicate that although oxysterols likely activate both pro- and anti-inflammatory pathways in the placenta, the predominant effect is the promotion of placental inflammation via TLR4-dependent activation of NF-κB.
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Affiliation(s)
- Irving L M H Aye
- School of Women's and Infants' Health, Faculty of Medicine, Dentistry and Health Sciences, King Edward Memorial Hospital, 374 Bagot Rd, Subiaco, The University of Western Australia, Perth, WA 6008, Australia.
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Singh AT, Dharmarajan A, Aye ILMH, Keelan JA. Sphingosine-sphingosine-1-phosphate pathway regulates trophoblast differentiation and syncytialization. Reprod Biomed Online 2011; 24:224-34. [PMID: 22197131 DOI: 10.1016/j.rbmo.2011.10.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 10/25/2011] [Accepted: 10/26/2011] [Indexed: 12/30/2022]
Abstract
Sphingosine and sphingosine-1-phosphate (S1P) are involved in regulating cell differentiation. This study postulated that changes in sphingolipid biosynthesis and metabolism are important in trophoblast syncytialization and therefore examined the production, metabolism and actions of sphingosine and S1P during spontaneous trophoblast differentiation and fusion in vitro. Significant declines in intracellular sphingosine concentration (P≤0.05) and sphingosine kinase 1 (SPHK1) expression (P≤0.01) were observed during trophoblast syncytialization. Secreted S1P concentrations dropped steeply after 72h, before rising to basal concentrations with syncytialization. Intracellular S1P concentrations were undetectable throughout. Treating cells with exogenous sphingosine (P≤0.01), S1P (P≤0.001) or a specific SPHK1 inhibitor (P≤0.05) for up to 72h in culture significantly inhibited trophoblast differentiation (measured as reduced human chorionic gonadotrophin production); effects on other biochemical and morphological markers of differentiation were absent or inconsistent. Phosphorylation of Akt, an established down-stream target of S1P that spontaneously declines with trophoblast differentiation, was markedly reduced by S1P (P≤0.05). In conclusion, changes in the sphingosine-S1P pathway are involved in the regulation of trophoblast differentiation in term human placenta. Dysregulation of sphingolipid homeostasis could, therefore, disrupt placental formation and function with deleterious consequences for pregnancy outcome.
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Affiliation(s)
- Ambika T Singh
- School of Women's and Infants' Health, The University of Western Australia, Subiaco, Perth, Western Australia, Australia
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Affiliation(s)
- J A Keelan
- School of Women's and Infants' Health, University of Western Australia, King Edward Memorial Hospital, 374 Bagot Rd, Subiaco, Perth WA 6008, Australia.
| | - I L M H Aye
- School of Women's and Infants' Health, University of Western Australia, Australia
| | - P J Mark
- School of Anatomy and Human Biology, University of Western Australia, Australia
| | - B J Waddell
- School of Anatomy and Human Biology, University of Western Australia, Australia
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Aye ILMH, Waddell BJ, Mark PJ, Keelan JA. Placental ABCA1 and ABCG1 transporters efflux cholesterol and protect trophoblasts from oxysterol induced toxicity. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1801:1013-24. [PMID: 20570635 DOI: 10.1016/j.bbalip.2010.05.015] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 05/16/2010] [Accepted: 05/27/2010] [Indexed: 10/19/2022]
Abstract
ATP-binding cassette (ABC) transporters ABCA1 and ABCG1 mediate the efflux of cholesterol and other sterols. Both transporters are expressed on the fetal capillaries of the placenta and are involved in maternal-to-fetal cholesterol delivery. In this study, we report that ABCA1 and ABCG1 are also present on the syncytiotrophoblast, the maternal facing placental membrane. Syncytial ABCA1 expression is apical, suggesting a role in cholesterol efflux to the mother, while ABCG1 is expressed basolaterally indicating transport to the fetus. Silencing of ABCA1 expression in primary trophoblasts in culture, or pharmacological antagonism by glyburide, decreased cholesterol efflux to apolipoprotein A-I (apoA-I) compared to controls, while ABCG1-silencing decreased cholesterol efflux to high density lipoproteins (HDL). In contrast, treatment with endogenous or synthetic LXR alpha/beta ligands such as T0901317 increased ABCA1 and ABCG1 expression and enhanced cholesterol efflux to apoA-I and HDL, respectively, while treatment with pharmacological PPAR-alpha or -gamma ligands was without effect. Trophoblasts transfected with ABCA1 or ABCG1 siRNA were more sensitive to toxic oxysterols substrates (25-hydroxycholesterol and 7-ketocholesterol) compared to mock-transfected cells, while prior treatment with T0901317 reduced oxysterol-mediated toxicity. These results identify syncytial ABCA1 and ABCG1 as important, inducible cholesterol transporters which also prevent placental accumulation of cytotoxic oxysterols.
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Affiliation(s)
- Irving L M H Aye
- School of Women's & Infants' Health, Faculty of Medicine, Dentistry and Health Sciences, University of Western Australia, Perth, Western Australia, Australia
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Aye ILMH, Paxton JW, Evseenko DA, Keelan JA. Expression, localisation and activity of ATP binding cassette (ABC) family of drug transporters in human amnion membranes. Placenta 2007; 28:868-77. [PMID: 17482262 DOI: 10.1016/j.placenta.2007.03.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2006] [Revised: 02/27/2007] [Accepted: 03/03/2007] [Indexed: 01/16/2023]
Abstract
Placental ATP-binding cassette (ABC) transporters limit fetal exposure to xenobiotics by regulating transplacental passage into the fetal circulation; their expression and function in fetal membranes, however, has not been studied. In the present study the expression, localisation and function of ABC transporters in human amnion was examined to explore their potential role in modulating amniotic fluid drug disposition in pregnancy. Single-assay oligo-microarrays were used to profile amnion gene expression, and drug transporters expressed at significant levels were identified and selected for further studies. The expression of ABCG2/breast cancer resistance protein (BCRP) and multidrug resistance-associated proteins (MRP) 1 (ABCC1), 2 (ABCC2) and 5 (ABCC5) was detected on the arrays, and verified by RT-PCR and immunoblotting. On confocal microscopy of fetal membrane cryosections, MRP1 and MRP5 were immunolocalised to both apical and basolateral surfaces of the amniotic epithelium, while MRP2 was expressed at low levels only in the apical membrane. BCRP in contrast showed cytoplasmic staining throughout the amniotic epithelium. In addition to the amnion, MRP1 and BCRP immunostaining was observed in the chorion and the decidua. Cell accumulation studies using selective MRP and BCRP inhibitors showed the transporters to be functionally active in amnion epithelial monolayer cultures. In contrast, transwell transport studies using intact amnion membranes did not show significant vectorial transport. These findings identify the amnion as a novel site of ABC drug transporter expression. Functional studies indicate that they may act primarily to prevent cellular xenobiotic accumulation, rather than to confer fetal protection through reduced accumulation in amniotic fluid.
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Affiliation(s)
- I L M H Aye
- Liggins Institute, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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