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Guadix P, Corrales I, Vilariño-García T, Rodríguez-Chacón C, Sánchez-Jiménez F, Jiménez-Cortegana C, Dueñas JL, Sánchez-Margalet V, Pérez-Pérez A. Expression of nutrient transporters in placentas affected by gestational diabetes: role of leptin. Front Endocrinol (Lausanne) 2023; 14:1172831. [PMID: 37497352 PMCID: PMC10366688 DOI: 10.3389/fendo.2023.1172831] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 06/14/2023] [Indexed: 07/28/2023] Open
Abstract
Gestational diabetes mellitus (GDM) is the most frequent pathophysiological state of pregnancy, which in many cases produces fetuses with macrosomia, requiring increased nutrient transport in the placenta. Recent studies by our group have demonstrated that leptin is a key hormone in placental physiology, and its expression is increased in placentas affected by GDM. However, the effect of leptin on placental nutrient transport, such as transport of glucose, amino acids, and lipids, is not fully understood. Thus, we aimed to review literature on the leptin effect involved in placental nutrient transport as well as activated leptin signaling pathways involved in the expression of placental transporters, which may contribute to an increase in placental nutrient transport in human pregnancies complicated by GDM. Leptin appears to be a relevant key hormone that regulates placental transport, and this regulation is altered in pathophysiological conditions such as gestational diabetes. Adaptations in the placental capacity to transport glucose, amino acids, and lipids may underlie both under- or overgrowth of the fetus when maternal nutrient and hormone levels are altered due to changes in maternal nutrition or metabolic disease. Implementing new strategies to modulate placental transport may improve maternal health and prove effective in normalizing fetal growth in cases of intrauterine growth restriction and fetal overgrowth. However, further studies are needed to confirm this hypothesis.
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Affiliation(s)
- Pilar Guadix
- Obstetrics and Gynecology Service, Virgen Macarena University Hospital, School of Medicine, University of Seville, Seville, Spain
| | - Isabel Corrales
- Obstetrics and Gynecology Service, Virgen Macarena University Hospital, School of Medicine, University of Seville, Seville, Spain
| | - Teresa Vilariño-García
- Clinical Biochemistry Service, Virgen del Rocio University Hospital, School of Medicine, University of Seville, Seville, Spain
| | - Carmen Rodríguez-Chacón
- Clinical Biochemistry Service, Virgen Macarena University Hospital and Department of Medical Biochemistry and Molecular Biology and Immunology, School of Medicine, University of Seville, Seville, Spain
| | - Flora Sánchez-Jiménez
- Clinical Biochemistry Service, Virgen Macarena University Hospital and Department of Medical Biochemistry and Molecular Biology and Immunology, School of Medicine, University of Seville, Seville, Spain
| | - Carlos Jiménez-Cortegana
- Clinical Biochemistry Service, Virgen Macarena University Hospital and Department of Medical Biochemistry and Molecular Biology and Immunology, School of Medicine, University of Seville, Seville, Spain
| | - José L. Dueñas
- Obstetrics and Gynecology Service, Virgen Macarena University Hospital, School of Medicine, University of Seville, Seville, Spain
| | - Víctor Sánchez-Margalet
- Clinical Biochemistry Service, Virgen Macarena University Hospital and Department of Medical Biochemistry and Molecular Biology and Immunology, School of Medicine, University of Seville, Seville, Spain
| | - Antonio Pérez-Pérez
- Clinical Biochemistry Service, Virgen Macarena University Hospital and Department of Medical Biochemistry and Molecular Biology and Immunology, School of Medicine, University of Seville, Seville, Spain
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McCoard S, Haack N, Heiser A, Maclean P. Effect of birth rank, and placentome subtype on expression of genes involved in placental nutrient transport in sheep. Theriogenology 2023; 203:109-117. [PMID: 37023492 DOI: 10.1016/j.theriogenology.2023.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 02/23/2023] [Accepted: 03/09/2023] [Indexed: 03/17/2023]
Abstract
Placental function is a key determinant of fetal growth and development that can be influenced by maternal and fetal environmental factors. The molecular mechanisms by which the placenta senses and responds to environmental cues are poorly understood. This exploratory study aimed to characterize the effect of birth rank (single vs. twin) and placentome morphologic subtype on expression of genes involved in nutrient transport, angiogenesis, immunity and stress response. Cotyledonary tissue was collected from type A, B and C placentomes from five single and six twin fetuses at 140 days of gestation. GLUT1 and GLUT3 were the most highly expressed genes consistent with the high demand for glucose to support fetal growth. Expression of BCKDHβ and IGF-2 was 1.3- and 1.5-fold higher, respectively, and PCYT1A was 3-fold lower in singles compared to twins (P < 0.05) while no other differences in gene expression were observed between birth ranks. Expression of EAAT2 and LAT2 was higher while PCYT1A was lower in A compared to B type cotyledons. Expression of GUCY1B1/3 and IGF-1 was higher while CD98 and LAT2 were lower in type B compared to C cotyledons (P < 0.05). Compared to type C cotyledons, expression of EAAT2, IGF-1, IGF-2, LAT1 was higher, while TEK was lower in type A cotyledons. The effects of birth rank on placental gene expression in this study indicated that placental nutrient transport and/or function differs between single and twin pregnancies in sheep. Differences in gene expression between the placentome subtypes suggests that changes in placentome morphology are associated with shifts in amino acid transport and metabolism, oxidative stress and angiogenesis and/or blood flow. This study highlights that placental gene expression differs in response to birth rank and placentome morphologic subtype which suggests that both maternal and fetal factors may influence placental function in sheep. These associations provide insights into gene pathways for more targeted future investigations as well as potential adaptations to improve placental efficiency to support fetal growth in twin pregnancies.
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Zaugg J, Solenthaler F, Albrecht C. Materno-fetal iron transfer and the emerging role of ferroptosis pathways. Biochem Pharmacol 2022; 202:115141. [PMID: 35700759 DOI: 10.1016/j.bcp.2022.115141] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 06/03/2022] [Accepted: 06/07/2022] [Indexed: 11/28/2022]
Abstract
A successful pregnancy and the birth of a healthy baby depend to a great extent on the controlled supply of essential nutrients via the placenta. Iron is essential for mitochondrial energy supply and oxygen distribution via the blood. However, its high reactivity requires tightly regulated transport processes. Disturbances of maternal-fetal iron transfer during pregnancy can aggravate or lead to severe pathological consequences for the mother and the fetus with lifelong effects. Furthermore, high intracellular iron levels due to disturbed gestational iron homeostasis have recently been associated with the non-apoptotic cell death pathway called ferroptosis. Therefore, the investigation of transplacental iron transport mechanisms, their physiological regulation and potential risks are of high clinical importance. The present review summarizes the current knowledge on principles and regulatory mechanisms underlying materno-fetal iron transport and gives insight into common pregnancy conditions in which iron homeostasis is disturbed. Moreover, the significance of the newly emerging ferroptosis pathway and its impact on the regulation of placental iron homeostasis, oxidative stress and gestational diseases will be discussed.
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Affiliation(s)
- Jonas Zaugg
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Switzerland; Swiss National Centre of Competence in Research (NCCR) TransCure, University of Bern, Switzerland
| | - Fabia Solenthaler
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Switzerland; Swiss National Centre of Competence in Research (NCCR) TransCure, University of Bern, Switzerland
| | - Christiane Albrecht
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Switzerland; Swiss National Centre of Competence in Research (NCCR) TransCure, University of Bern, Switzerland.
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Zhang CZ, Sang D, Wu BS, Li SL, Zhang CH, Jin L, Li JX, Gu Y, Ga NMR, Hua M, Sun HZ. Effects of dietary supplementation with N-carbamylglutamate on maternal endometrium and fetal development during early pregnancy in Inner Mongolia white cashmere goats. Anim Sci J 2022; 93:e13693. [PMID: 35258155 DOI: 10.1111/asj.13693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 01/10/2022] [Accepted: 01/16/2022] [Indexed: 11/28/2022]
Abstract
This study investigated the effects of dietary supplementation with N-carbamylglutamate (NCG) on maternal endometrium and fetal development during early pregnancy of Inner Mongolia white cashmere goats. Forty-eight pregnant Inner Mongolia white cashmere goats (average age 3 years old, average lactation parity 2, and average body weight 43.81 ± 2.66 kg) were randomly allocated to three groups: a basal diet (control group, n = 16), a basal diet plus 0.30-g NCG/d (NCG1 group, n = 16), and a basal diet plus 0.40-g NCG/d (NCG2 group, n = 16). All of the does were housed in individual pens and the NCG treatment was conducted from Days 0 to 90 of pregnancy. At Days 17 and 90 of pregnancy, six representative pregnant does in each group were slaughtered. The current study results demonstrated that maternal NCG administration during early pregnancy effectively increased the arginine family of amino acids and the glucogenic amino acids concentrations and promoted the mRNA expression of osteopontin (OPN), αv and β3 integrins, and endometrial development of Inner Mongolia white cashmere goats. The supplementation improved the fetal brown adipose tissue (BAT) stores and the mRNA expression of UCP-1 and BMP7, thereby helping to the fetal early development.
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Affiliation(s)
- Chong Zhi Zhang
- Institute for Animal Nutrition and Feed Research, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Dan Sang
- Institute for Animal Nutrition and Feed Research, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Bao Sheng Wu
- Institute for Animal Nutrition and Feed Research, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Sheng Li Li
- Institute for Animal Nutrition and Feed Research, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Chun Hua Zhang
- Institute for Animal Nutrition and Feed Research, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Lu Jin
- Institute for Animal Nutrition and Feed Research, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Jin Xia Li
- Institute for Animal Nutrition and Feed Research, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Ying Gu
- Institute for Animal Nutrition and Feed Research, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Na Mei Ri Ga
- Institute for Animal Nutrition and Feed Research, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Mei Hua
- College of Animal Science and Technology, Inner Mongolia University for Nationalities, Tongliao, China
| | - Hai Zhou Sun
- Institute for Animal Nutrition and Feed Research, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
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Cui C, Wu C, Wang J, Zheng X, Ma Z, Zhu P, Guan W, Zhang S, Chen F. Leucine supplementation during late gestation globally alters placental metabolism and nutrient transport via modulation of the PI3K/AKT/mTOR signaling pathway in sows. Food Funct 2022; 13:2083-2097. [PMID: 35107470 DOI: 10.1039/d1fo04082k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In a previously published study we reported that sow dietary leucine supplementation during late pregnancy significantly improved newborn piglet birth weight by stimulating protein synthesis in the longissimus dorsi muscle. However, there is still limited knowledge as to whether leucine can exert its effects on the placenta, one of the most important temporal organs during pregnancy, to promote maternal-fetal nutrient supply and thus contribute to fetal intrauterine development. Therefore, we tested this hypothesis in the present study. In total, 150 sows at day 90 of gestation were divided into three groups and fed with either a control diet (CON), CON + 0.4% Leu or CON + 0.8% Leu, respectively, until parturition. Placental metabolomics, full spectrum amino acids and nutrient transporters were systematically analyzed after sample collection. The results indicated that Leu supplementation led to an altered placental metabolism with an increased number of metabolites related to glycolysis and the oxidation of fatty acids, as well as elevated levels of amino acid accumulation in the placenta. In addition, nutrient transporters of amino acids, glucose and fatty acids in the placenta were globally up-regulated and several enzymes related to energy metabolism, including hexokinase, succinate dehydrogenase, lactated hydrogenase, glycogen phosphorylase and hydroxyacyl-CoA-dehydrogenase, were also significantly increased with no change observed in the antioxidative status of those groups with Leu supplementation. Furthermore, the phosphorylation of PI3K, Akt, and mTOR was enhanced in the placenta of sows undergoing Leu treatment. Collectively, we concluded that supplementing the diets of sows with Leu during late gestation globally altered placental metabolism and promoted maternal-fetus nutrient transport (amino acids, glucose, and fatty acids) via modulation of the PI3K/Akt/mTOR signaling pathway.
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Affiliation(s)
- Chang Cui
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
| | - Caichi Wu
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
| | - Jun Wang
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
| | - Xiaoyu Zheng
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
| | - Ziwei Ma
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
| | - Pengwei Zhu
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
| | - Wutai Guan
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou 510642, China. .,College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China
| | - Shihai Zhang
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou 510642, China. .,College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China
| | - Fang Chen
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou 510642, China. .,College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China
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Prater M, Hamilton RS, Wa Yung H, Sharkey AM, Robson P, Abd Hamid NE, Jauniaux E, Charnock-Jones DS, Burton GJ, Cindrova-Davies T. RNA-Seq reveals changes in human placental metabolism, transport and endocrinology across the first-second trimester transition. Biol Open 2021; 10:268993. [PMID: 34100896 PMCID: PMC8214423 DOI: 10.1242/bio.058222] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 04/09/2021] [Indexed: 12/13/2022] Open
Abstract
The human placenta is exposed to major environmental changes towards the end of the first trimester associated with full onset of the maternal arterial placental circulation. Changes include a switch from histotrophic to hemotrophic nutrition, and a threefold rise in the intraplacental oxygen concentration. We evaluated their impact on trophoblast development and function using RNA-sequencing (RNA-Seq) and DNA-methylation analyses performed on the same chorionic villous samples at 7-8 (n=8) and 13-14 (n=6) weeks of gestation. Reads were adjusted for fetal sex. Most DEGs were associated with protein processing in the endoplasmic reticulum (ER), hormone secretion, transport, extracellular matrix, vasculogenesis, and reactive oxygen species metabolism. Transcripts higher in the first trimester were associated with synthesis and ER processing of peptide hormones, and glycolytic pathways. Transcripts encoding proteins mediating transport of oxygen, lipids, protein, glucose, and ions were significantly increased in the second trimester. The motifs of CBX3 and BCL6 were significantly overrepresented, indicating the involvement of these transcription factor networks in the regulation of trophoblast migration, proliferation and fusion. These findings are consistent with a high level of cell proliferation and hormone secretion by the early placenta to secure implantation in a physiological low-oxygen environment.
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Affiliation(s)
- Malwina Prater
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Russell S Hamilton
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK.,Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Hong Wa Yung
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Andrew M Sharkey
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK.,Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Paul Robson
- The Jackson Laboratory, The JAX Center for Genetics of Fertility and Reproduction, 10 Discovery Drive, Farmington, CT 06032, USA.,Genome Institute of Singapore, Singapore 138672, Singapore
| | | | - Eric Jauniaux
- Department of Obstetrics and Gynaecology, EGA Institute for Women's Health, Faculty of Population Health Sciences, University College London, London, WC1E 6BT, UK
| | - D Stephen Charnock-Jones
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK.,Department of Obstetrics and Gynaecology, University of Cambridge, The Rosie Hospital, Cambridge, CB2 0SW, UK.,National Institute for Health Research, Cambridge Biomedical Research Centre, Cambridge CB2 0QQ, UK
| | - Graham J Burton
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Tereza Cindrova-Davies
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
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Counter-directed leucine gradient promotes amino acid transfer across the human placenta. J Nutr Biochem 2021; 96:108760. [PMID: 33964466 DOI: 10.1016/j.jnutbio.2021.108760] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 02/04/2021] [Accepted: 04/16/2021] [Indexed: 02/01/2023]
Abstract
The developing fetus is highly vulnerable to imbalances in the supply of essential amino acids (AA). Transplacental AA transfer depends on complex interactions between accumulative transporters, exchangers and facilitators, which maintain both intra-extracellular and materno-fetal substrate gradients. We determined physiological AA gradients between maternal and fetal blood and assessed their importance by studying maternal-fetal leucine transfer in human trophoblasts. Maternal-venous and corresponding fetal-arterial/fetal-venous sera were collected from 22 healthy patients at partum. The acquisition of the full AA spectra in serum was performed by ion exchange chromatography. Physiological materno-fetal AA levels were evaluated using paired two-way ANOVA with Tukey's correction. AA concentrations and gradients were tested for associations with anthropometric data by Spearman correlation analysis. Functional effects of a physiological leucine gradient versus equimolar concentrations were tested in BeWo cells using L-[3H]-leucine in conventional and Transwell-based uptake and transfer experiments. The LAT1/SLC7A5-specific inhibitor JPH203 was used to evaluate LAT1-transporter-mediated leucine transport. Maternal AA concentrations correlated with preconceptional and maternal weights at partum. Interestingly, low materno-fetal AA gradients were associated with maternal weight, BMI and gestational weight gain. Leucine uptake was promoted by increased extracellular substrate concentrations. Materno-fetal leucine transfer was significantly increased against a 137µM leucine gradient demonstrating that transplacental leucine transport is stimulated by a counter-directed gradient. Moreover, leucine transfer was inhibited by 10µM JPH203 confirming that Leu transport across the trophoblast monolayer is LAT1-dependent. This study demonstrates a currently underestimated effect of transplacental AA gradients on efficient leucine transfer which could severely affect fetal development.
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Owaydhah WH, Ashton N, Verrey F, Glazier JD. Differential expression of system L amino acid transporter subtypes in rat placenta and yolk sac. Placenta 2020; 103:188-198. [PMID: 33160252 DOI: 10.1016/j.placenta.2020.10.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/12/2020] [Accepted: 10/28/2020] [Indexed: 01/01/2023]
Abstract
INTRODUCTION Amino acid transport across the placenta is crucial for fetal growth. In rodent models, the visceral yolk sac (referred to as yolk sac hereafter) is also likely to contribute to fetal amino acid provision. System L amino acid transporters mediate the transport of essential amino acids. System L activity is mediated by light chains LAT1 (Slc7a5) and LAT2 (Slc7a8) which form functional complexes by heterodimeric linkage to CD98 (Slc3a2). LAT4 (Slc43a2) is monomeric, possessing overlapping amino acid substrate specificity with LAT1 and LAT2. METHODS This study investigates the expression of these LAT subtypes in fetus-matched rat placenta and yolk sac. RESULTS Slc7a5, Slc7a8 and Slc43a2 transcripts were expressed in placenta and yolk sac with similar expression patterns between sexes. LAT1 expression was significantly higher in placenta than yolk sac. Conversely, LAT2 and LAT4 expression was significantly higher in yolk sac than placenta; CD98 expression was comparable. LAT1, LAT2, LAT4 and CD98 were distributed to rat placental labyrinth zone (LZ) and junctional zone (JZ). LAT1 and LAT4 demonstrated higher expression in LZ, whilst LAT2 was more intensely distributed to JZ. LAT1, LAT2, LAT4 and CD98 were expressed in yolk sac, with punctate LAT1 staining to endodermal cell cytoplasm, contrasting with the intense LAT2, LAT4 and CD98 endodermal cell basolateral distribution, accounting for greater LAT2 and LAT4 expression in yolk sac compared to placenta. CONCLUSION LAT1, LAT2 and LAT4 are expressed in rat placenta and yolk sac implicating a combined role for these LAT subtypes in supporting fetal growth and development.
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Affiliation(s)
- Wejdan H Owaydhah
- Maternal and Fetal Health Research Centre, Division of Developmental Biology and Medicine, St Mary's Hospital, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9WL, UK
| | - Nick Ashton
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9NT, UK
| | - François Verrey
- Institute of Physiology, University of Zurich, Zurich, CH-8057, Switzerland
| | - Jocelyn D Glazier
- Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, UK.
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Kan NE, Khachatryan ZV, Chagovets VV, Starodubtseva NL, Amiraslanov EY, Tyutyunnik VL, Lomova NA, Frankevich VE. [Analysis of metabolic pathways in intrauterine growth restriction]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2020; 66:174-180. [PMID: 32420900 DOI: 10.18097/pbmc20206602174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Objective was to analyze metabolic pathways based on a study of the metabolomic profile of pregnant women with intrauterine growth restriction. The metabolic profile of pregnant women with fetal growth restriction has been analyzed using liquid chromatography-mass spectrometry. At the second stage pathways were identified using SMPDB and MetaboAnalyst databases to clarify the relationship between metabolites. Biological networks allow to determine the effect of proteins on the metabolic pathways involved in pathogenesis of IUGR and determine the epigenetic mechanisms of its formation.
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Affiliation(s)
- N E Kan
- Academician V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
| | - Z V Khachatryan
- Academician V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
| | - V V Chagovets
- Academician V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
| | - N L Starodubtseva
- Academician V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
| | - E Yu Amiraslanov
- Academician V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
| | - V L Tyutyunnik
- Academician V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
| | - N A Lomova
- Academician V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
| | - V E Frankevich
- Academician V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
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Drożdżyk K, Sawicka M, Bahamonde-Santos MI, Jonas Z, Deneka D, Albrecht C, Dutzler R. Cryo-EM structures and functional properties of CALHM channels of the human placenta. eLife 2020; 9:e55853. [PMID: 32374262 PMCID: PMC7242029 DOI: 10.7554/elife.55853] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 05/05/2020] [Indexed: 01/08/2023] Open
Abstract
The transport of substances across the placenta is essential for the development of the fetus. Here, we were interested in the role of channels of the calcium homeostasis modulator (CALHM) family in the human placenta. By transcript analysis, we found the paralogs CALHM2, 4, and 6 to be highly expressed in this organ and upregulated during trophoblast differentiation. Based on electrophysiology, we observed that activation of these paralogs differs from the voltage- and calcium-gated channel CALHM1. Cryo-EM structures of CALHM4 display decameric and undecameric assemblies with large cylindrical pore, while in CALHM6 a conformational change has converted the pore shape into a conus that narrows at the intracellular side, thus describing distinct functional states of the channel. The pore geometry alters the distribution of lipids, which occupy the cylindrical pore of CALHM4 in a bilayer-like arrangement whereas they have redistributed in the conical pore of CALHM6 with potential functional consequences.
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Affiliation(s)
| | - Marta Sawicka
- Department of Biochemistry, University of ZurichZurichSwitzerland
| | | | - Zaugg Jonas
- Institute of Biochemistry and Molecular Medicine, University of BernBernSwitzerland
| | - Dawid Deneka
- Department of Biochemistry, University of ZurichZurichSwitzerland
| | - Christiane Albrecht
- Institute of Biochemistry and Molecular Medicine, University of BernBernSwitzerland
| | - Raimund Dutzler
- Department of Biochemistry, University of ZurichZurichSwitzerland
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11
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Grimm MJ. Engineering and women's health: a slow start, but gaining momentum. Interface Focus 2019; 9:20190017. [PMID: 31263535 DOI: 10.1098/rsfs.2019.0017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2019] [Indexed: 12/12/2022] Open
Abstract
While biomedical engineers have participated in research studies that focus on understanding aspects particular to women's health since the 1950s, the depth and breadth of the research have increased significantly in the last 15-20 years. It has been increasingly clear that engineers can lend important knowledge and analysis to address questions that are key to understanding physiology and pathophysiology related to women's health. This historical survey identifies some of the earliest contributions of engineers to exploring aspects of women's health, from the behaviour of key tissues, to issues of reproduction and breast cancer. In addition, some of the more recent work in each area is identified and areas deserving additional attention are described. The interdisciplinary nature of this area of engineering, along with the growing interest within the field of biomedical engineering, promise to bring exciting new discoveries and expand knowledge that will positively impact women's health in the near future.
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Affiliation(s)
- Michele J Grimm
- Wielenga Creative Engineering Endowed Professor, Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA
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Methylmercury Uptake into BeWo Cells Depends on LAT2-4F2hc, a System L Amino Acid Transporter. Int J Mol Sci 2017; 18:ijms18081730. [PMID: 28786956 PMCID: PMC5578120 DOI: 10.3390/ijms18081730] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/28/2017] [Accepted: 08/01/2017] [Indexed: 12/24/2022] Open
Abstract
The organic mercury compound methylmercury (MeHg) is able to target the fetal brain. However, the uptake of the toxicant into placental cells is incompletely understood. MeHg strongly binds to thiol-S containing molecules such as cysteine. This MeHg-l-cysteine exhibits some structural similarity to methionine. System L plays a crucial role in placental transport of essential amino acids such as leucine and methionine and thus has been assumed to also transport MeHg-l-cysteine across the placenta. The uptake of methylmercury and tritiated leucine and methionine into the choriocarcinoma cell line BeWo was examined using transwell assay and small interfering (si)RNA mediated gene knockdown. Upon the downregulation of large neutral amino acids transporter (LAT)2 and 4F2 cell-surface antigen heavy chain (4F2hc), respectively, the levels of [3H]leucine in BeWo cells are significantly reduced compared to controls treated with non-targeting siRNA (p < 0.05). The uptake of [3H]methionine was reduced upon LAT2 down-regulation as well as methylmercury uptake after 4F2hc silencing (p < 0.05, respectively). These findings suggest an important role of system L in the placental uptake of the metal. Comparing the cellular accumulation of mercury, leucine, and methionine, it can be assumed that (1) MeHg is transported through system L amino acid transporters and (2) system L is responsible for the uptake of amino acids and MeHg primarily at the apical membrane of the trophoblast. The findings together can explain why mercury in contrast to other heavy metals such as lead or cadmium is efficiently transported to fetal blood.
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Abstract
Epidemiological evidence links an individual's susceptibility to chronic disease in adult life to events during their intrauterine phase of development. Biologically this should not be unexpected, for organ systems are at their most plastic when progenitor cells are proliferating and differentiating. Influences operating at this time can permanently affect their structure and functional capacity, and the activity of enzyme systems and endocrine axes. It is now appreciated that such effects lay the foundations for a diverse array of diseases that become manifest many years later, often in response to secondary environmental stressors. Fetal development is underpinned by the placenta, the organ that forms the interface between the fetus and its mother. All nutrients and oxygen reaching the fetus must pass through this organ. The placenta also has major endocrine functions, orchestrating maternal adaptations to pregnancy and mobilizing resources for fetal use. In addition, it acts as a selective barrier, creating a protective milieu by minimizing exposure of the fetus to maternal hormones, such as glucocorticoids, xenobiotics, pathogens, and parasites. The placenta shows a remarkable capacity to adapt to adverse environmental cues and lessen their impact on the fetus. However, if placental function is impaired, or its capacity to adapt is exceeded, then fetal development may be compromised. Here, we explore the complex relationships between the placental phenotype and developmental programming of chronic disease in the offspring. Ensuring optimal placentation offers a new approach to the prevention of disorders such as cardiovascular disease, diabetes, and obesity, which are reaching epidemic proportions.
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Affiliation(s)
- Graham J Burton
- Centre for Trophoblast Research and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom; and Department of Medicine, Knight Cardiovascular Institute, and Moore Institute for Nutrition and Wellness, Oregon Health and Science University, Portland, Oregon
| | - Abigail L Fowden
- Centre for Trophoblast Research and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom; and Department of Medicine, Knight Cardiovascular Institute, and Moore Institute for Nutrition and Wellness, Oregon Health and Science University, Portland, Oregon
| | - Kent L Thornburg
- Centre for Trophoblast Research and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom; and Department of Medicine, Knight Cardiovascular Institute, and Moore Institute for Nutrition and Wellness, Oregon Health and Science University, Portland, Oregon
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14
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Genetics of the human placenta: implications for toxicokinetics. Arch Toxicol 2016; 90:2563-2581. [DOI: 10.1007/s00204-016-1816-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/04/2016] [Indexed: 10/21/2022]
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15
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Panitchob N, Widdows KL, Crocker IP, Johnstone ED, Please CP, Sibley CP, Glazier JD, Lewis RM, Sengers BG. Computational modelling of placental amino acid transfer as an integrated system. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1451-61. [PMID: 27045077 PMCID: PMC4884669 DOI: 10.1016/j.bbamem.2016.03.028] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/22/2016] [Accepted: 03/31/2016] [Indexed: 01/31/2023]
Abstract
Placental amino acid transfer is essential for fetal development and its impairment is associated with poor fetal growth. Amino acid transfer is mediated by a broad array of specific plasma membrane transporters with overlapping substrate specificity. However, it is not fully understood how these different transporters work together to mediate net flux across the placenta. Therefore the aim of this study was to develop a new computational model to describe how human placental amino acid transfer functions as an integrated system. Amino acid transfer from mother to fetus requires transport across the two plasma membranes of the placental syncytiotrophoblast, each of which contains a distinct complement of transporter proteins. A compartmental modelling approach was combined with a carrier based modelling framework to represent the kinetics of the individual accumulative, exchange and facilitative classes of transporters on each plasma membrane. The model successfully captured the principal features of transplacental transfer. Modelling results clearly demonstrate how modulating transporter activity and conditions such as phenylketonuria, can increase the transfer of certain groups of amino acids, but that this comes at the cost of decreasing the transfer of others, which has implications for developing clinical treatment options in the placenta and other transporting epithelia. First computational model of placental amino acid transfer as an integrated system Increased activity of a transporter does not mean increased transfer to the fetus. Increasing transfer of certain amino acids can reduce the transfer of others. Amino acid composition as well as concentration determines transfer to the fetus. Modelling of phenylketonuria suggests inhibition by excess maternal phenylalanine.
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Affiliation(s)
- N Panitchob
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, UK
| | - K L Widdows
- Maternal & Fetal Health Research Centre, Institute of Human Development, University of Manchester, UK; St. Mary's Hospital & Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, UK
| | - I P Crocker
- Maternal & Fetal Health Research Centre, Institute of Human Development, University of Manchester, UK; St. Mary's Hospital & Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, UK
| | - E D Johnstone
- Maternal & Fetal Health Research Centre, Institute of Human Development, University of Manchester, UK; St. Mary's Hospital & Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, UK
| | - C P Please
- Mathematical Institute, Oxford University, Oxford, UK
| | - C P Sibley
- Maternal & Fetal Health Research Centre, Institute of Human Development, University of Manchester, UK; St. Mary's Hospital & Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, UK
| | - J D Glazier
- Maternal & Fetal Health Research Centre, Institute of Human Development, University of Manchester, UK; St. Mary's Hospital & Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, UK
| | - R M Lewis
- Faculty of Medicine, University of Southampton, UK; Institute for Life Sciences, University of Southampton, UK
| | - B G Sengers
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, UK; Institute for Life Sciences, University of Southampton, UK.
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16
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Abstract
To compare differences in metabolites between newborns with intrauterine growth restriction (IUGR) and those who are appropriate for gestational age (AGA) in order to understand the changes in metabolites of newborns with IUGR and to explore the possible metabolic mechanism of tissue and organ damages in patients with IUGR, with the ultimate goal of providing the basis for clinical intervention.A total of 60 newborns with IUGR and 60 AGA newborns who were hospitalized in the neonatal intensive care unit of our hospital between January 2011 and December 2015 and who underwent metabolic disease screening were enrolled in this study. The differences in 21 amino acids and 55 carnitines in peripheral blood, as well as changes in the ratios of free carnitine and acylcarnitine to total carnitine, were compared.Metabolites, particularly alanine, homocysteine, leucine, methionine, ornithine, serine, tyrosine, isovaleryl carnitine, and eicosenoyl carnitine, differed according to newborns' birth weight (<3rd percentile, 3rd-5th percentiles, 5th-10th percentiles, and 10th-90th percentiles), with those with lower birth weight showing the greater difference (P < 0.05). Metabolites also differed by gestational age, and the differences observed were mainly as follows: preterm and full-term newborns showed differences in metabolites, mainly in alanine, proline, cerotoyl carnitine, and tetradecanedioyl carnitine (P < 0.05); preterm and full-term AGA newborns showed differences in metabolites, mainly in alanine, glutamine, homocysteine, pipecolic acid, proline, heptanoyl carnitine, and sebacoyl carnitine (P < 0.05); and preterm and full-term newborns with IUGR showed differences in metabolites, mainly in arginine, glutamic acid, homocysteine, histidine, leucine, isoleucine, ornithine, serine, threonine, tryptophan, valine, heptanoyl carnitine, decanoyl carnitine, linoleyl carnitine, methylmalonyl carnitine, glutarylcarnitine, sebacoyl carnitine, hydroxyacetyl carnitine, and hydroxyhexadecancenyl carnitine (P < 0.05). Among newborns with IUGR, metabolites differed among males and females, mainly in aspartic acid, glutamic acid, and hexacosenoic acid (P < 0.05). Birth weight had no significant effects on free carnitine concentration or on the ratios of free carnitine and acylcarnitine to total carnitine (P < 0.05).IUGR infants exhibit significant abnormalities in amino acid and acylcarnitine metabolism, especially those with birth weight below the third percentile. With increasing birth weight, amino acids and acylcarnitines showed compensatory increases or reductions, and when birth weight reached the 10th percentile, the newborns with IUGR resembled the AGA newborns.
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Affiliation(s)
- Jing Liu
- From the Department of Neonatology and NICU of Bayi Children's Hospital, The Army General Hospital of the Chinese PLA (JL, X-XC, X-WL, WF, W-QZ); Graduate School, The Chinese PLA Medical College (X-XC), Beijing; and Graduate School, Southern Medical University, Guangzhou (WF), China
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17
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Lofthouse EM, Perazzolo S, Brooks S, Crocker IP, Glazier JD, Johnstone ED, Panitchob N, Sibley CP, Widdows KL, Sengers BG, Lewis RM. Phenylalanine transfer across the isolated perfused human placenta: an experimental and modeling investigation. Am J Physiol Regul Integr Comp Physiol 2015; 310:R828-36. [PMID: 26676251 PMCID: PMC5000773 DOI: 10.1152/ajpregu.00405.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/13/2015] [Indexed: 12/15/2022]
Abstract
Membrane transporters are considered essential for placental amino acid transfer, but the contribution of other factors, such as blood flow and metabolism, is poorly defined. In this study we combine experimental and modeling approaches to understand the determinants of [(14)C]phenylalanine transfer across the isolated perfused human placenta. Transfer of [(14)C]phenylalanine across the isolated perfused human placenta was determined at different maternal and fetal flow rates. Maternal flow rate was set at 10, 14, and 18 ml/min for 1 h each. At each maternal flow rate, fetal flow rates were set at 3, 6, and 9 ml/min for 20 min each. Appearance of [(14)C]phenylalanine was measured in the maternal and fetal venous exudates. Computational modeling of phenylalanine transfer was undertaken to allow comparison of the experimental data with predicted phenylalanine uptake and transfer under different initial assumptions. Placental uptake (mol/min) of [(14)C]phenylalanine increased with maternal, but not fetal, flow. Delivery (mol/min) of [(14)C]phenylalanine to the fetal circulation was not associated with fetal or maternal flow. The absence of a relationship between placental phenylalanine uptake and net flux of phenylalanine to the fetal circulation suggests that factors other than flow or transporter-mediated uptake are important determinants of phenylalanine transfer. These observations could be explained by tight regulation of free amino acid levels within the placenta or properties of the facilitated transporters mediating phenylalanine transport. We suggest that amino acid metabolism, primarily incorporation into protein, is controlling free amino acid levels and, thus, placental transfer.
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Affiliation(s)
- E M Lofthouse
- Faculty of Medicine, University of Southampton, Southampton, United Kingdom; Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - S Perazzolo
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom
| | - S Brooks
- Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - I P Crocker
- Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, and St. Mary's Hospital and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; and
| | - J D Glazier
- Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, and St. Mary's Hospital and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; and
| | - E D Johnstone
- Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, and St. Mary's Hospital and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; and
| | - N Panitchob
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom
| | - C P Sibley
- Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, and St. Mary's Hospital and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; and
| | - K L Widdows
- Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, and St. Mary's Hospital and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; and
| | - B G Sengers
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom; Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - R M Lewis
- Faculty of Medicine, University of Southampton, Southampton, United Kingdom; Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
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18
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Day PE, Ntani G, Crozier SR, Mahon PA, Inskip HM, Cooper C, Harvey NC, Godfrey KM, Hanson MA, Lewis RM, Cleal JK. Maternal Factors Are Associated with the Expression of Placental Genes Involved in Amino Acid Metabolism and Transport. PLoS One 2015; 10:e0143653. [PMID: 26657885 PMCID: PMC4682815 DOI: 10.1371/journal.pone.0143653] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 11/07/2015] [Indexed: 12/22/2022] Open
Abstract
Introduction Maternal environment and lifestyle factors may modify placental function to match the mother’s capacity to support the demands of fetal growth. Much remains to be understood about maternal influences on placental metabolic and amino acid transporter gene expression. We investigated the influences of maternal lifestyle and body composition (e.g. fat and muscle content) on a selection of metabolic and amino acid transporter genes and their associations with fetal growth. Methods RNA was extracted from 102 term Southampton Women’s Survey placental samples. Expression of nine metabolic, seven exchange, eight accumulative and three facilitated transporter genes was analyzed using quantitative real-time PCR. Results Increased placental LAT2 (p = 0.01), y+LAT2 (p = 0.03), aspartate aminotransferase 2 (p = 0.02) and decreased aspartate aminotransferase 1 (p = 0.04) mRNA expression associated with pre-pregnancy maternal smoking. Placental mRNA expression of TAT1 (p = 0.01), ASCT1 (p = 0.03), mitochondrial branched chain aminotransferase (p = 0.02) and glutamine synthetase (p = 0.05) was positively associated with maternal strenuous exercise. Increased glutamine synthetase mRNA expression (r = 0.20, p = 0.05) associated with higher maternal diet quality (prudent dietary pattern) pre-pregnancy. Lower LAT4 (r = -0.25, p = 0.05) and aspartate aminotransferase 2 mRNA expression (r = -0.28, p = 0.01) associated with higher early pregnancy diet quality. Lower placental ASCT1 mRNA expression associated with measures of increased maternal fat mass, including pre-pregnancy BMI (r = -0.26, p = 0.01). Lower placental mRNA expression of alanine aminotransferase 2 associated with greater neonatal adiposity, for example neonatal subscapular skinfold thickness (r = -0.33, p = 0.001). Conclusion A number of maternal influences have been linked with outcomes in childhood, independently of neonatal size; our finding of associations between placental expression of transporter and metabolic genes and maternal smoking, physical activity and diet raises the possibility that their effects are mediated in part through alterations in placental function. The observed changes in placental gene expression in relation to modifiable maternal factors are important as they could form part of interventions aimed at maintaining a healthy lifestyle for the mother and for optimal fetal development.
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Affiliation(s)
- Pricilla E. Day
- Institute of Developmental Sciences, University of Southampton, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Georgia Ntani
- MRC Lifecourse Epidemiology Unit, University of Southampton, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Sarah R. Crozier
- MRC Lifecourse Epidemiology Unit, University of Southampton, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Pam A. Mahon
- MRC Lifecourse Epidemiology Unit, University of Southampton, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Hazel M. Inskip
- MRC Lifecourse Epidemiology Unit, University of Southampton, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Cyrus Cooper
- MRC Lifecourse Epidemiology Unit, University of Southampton, Tremona Road, Southampton, SO16 6YD, United Kingdom
- NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Tremona Road, Southampton, SO16 6YD, United Kingdom
- NIHR Musculoskeletal Biomedical Research Unit, University of Oxford, Nuffield Orthopedic Centre, Headington, Oxford, OX3 7HE, United Kingdom
| | - Nicholas C. Harvey
- MRC Lifecourse Epidemiology Unit, University of Southampton, Tremona Road, Southampton, SO16 6YD, United Kingdom
- NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Keith M. Godfrey
- Institute of Developmental Sciences, University of Southampton, Tremona Road, Southampton, SO16 6YD, United Kingdom
- MRC Lifecourse Epidemiology Unit, University of Southampton, Tremona Road, Southampton, SO16 6YD, United Kingdom
- NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Mark A. Hanson
- Institute of Developmental Sciences, University of Southampton, Tremona Road, Southampton, SO16 6YD, United Kingdom
- NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Rohan M. Lewis
- Institute of Developmental Sciences, University of Southampton, Tremona Road, Southampton, SO16 6YD, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Jane K. Cleal
- Institute of Developmental Sciences, University of Southampton, Tremona Road, Southampton, SO16 6YD, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom
- * E-mail:
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Serov AS, Salafia C, Grebenkov DS, Filoche M. The role of morphology in mathematical models of placental gas exchange. J Appl Physiol (1985) 2015; 120:17-28. [PMID: 26494446 DOI: 10.1152/japplphysiol.00543.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 10/08/2015] [Indexed: 02/07/2023] Open
Abstract
The performance of the placenta as a gas exchanger has a direct impact on the future health of the newborn. To provide accurate estimates of respiratory gas exchange rates, placenta models need to account for both the physiology of exchange and the organ morphology. While the former has been extensively studied, accounting for the latter is still a challenge. The geometrical complexity of placental structure requires use of carefully crafted approximations. We present here the state of the art of respiratory gas exchange placenta modeling and demonstrate the influence of the morphology description on model predictions. Advantages and shortcomings of various classes of models are discussed, and experimental techniques that may be used for model validation are summarized. Several directions for future development are suggested.
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Affiliation(s)
- A S Serov
- Physique de la Matière Condensée, Centre National de la Recherche Scientifique, Ecole Polytechnique, Palaiseau, France; and
| | - C Salafia
- Placental Analytics, LLC, Larchmont, New York
| | - D S Grebenkov
- Physique de la Matière Condensée, Centre National de la Recherche Scientifique, Ecole Polytechnique, Palaiseau, France; and
| | - M Filoche
- Physique de la Matière Condensée, Centre National de la Recherche Scientifique, Ecole Polytechnique, Palaiseau, France; and
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20
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Lofthouse EM, Brooks S, Cleal JK, Hanson MA, Poore KR, O'Kelly IM, Lewis RM. Glutamate cycling may drive organic anion transport on the basal membrane of human placental syncytiotrophoblast. J Physiol 2015; 593:4549-59. [PMID: 26277985 PMCID: PMC4606536 DOI: 10.1113/jp270743] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 08/04/2015] [Indexed: 12/28/2022] Open
Abstract
Key points The placenta removes waste products, drugs and environmental toxins from the fetal circulation and two of the transport proteins responsible for this are OAT4 and OATP2B1 localised to the basal membrane of placental syncytiotrophoblast. We provide evidence that OAT4 and OATP2B1 mediate glutamate efflux when expressed in Xenopus oocytes and that in the perfused placenta, bromosulphothalein (an OAT4 and OATP2B1 substrate) stimulates glutamate efflux. Furthermore the efflux of glutamate can only be seen in the presence of aspartate, which will block glutamate reuptake by the placenta, consistent with cycling of glutamate across the basal membrane. We propose that glutamate efflux down its transmembrane gradient drives placental uptake via OAT4 and OATP2B1 from the fetal circulation and that reuptake of glutamate maintains this driving gradient.
Abstract The organic anion transporter OAT4 (SLC22A11) and organic anion transporting polypeptide OATP2B1 (SLCO2B1) are expressed in the basal membrane of the placental syncytiotrophoblast. These transporters mediate exchange whereby uptake of one organic anion is coupled to efflux of a counter‐ion. In placenta, these exchangers mediate placental uptake of substrates for oestrogen synthesis as well as clearing waste products and xenobiotics from the fetal circulation. However, the identity of the counter‐ion driving this transport in the placenta, and in other tissues, is unclear. While glutamate is not a known OAT4 or OATP2B1 substrate, we propose that its high intracellular concentration has the potential to drive accumulation of substrates from the fetal circulation. In the isolated perfused placenta, glutamate exchange was observed between the placenta and the fetal circulation. This exchange could not be explained by known glutamate exchangers. However, glutamate efflux was trans‐stimulated by an OAT4 and OATP2B1 substrate (bromosulphothalein). Exchange of glutamate for bromosulphothalein was only observed when glutamate reuptake was inhibited (by addition of aspartate). To determine if OAT4 and/or OATP2B1 mediate glutamate exchange, uptake and efflux of glutamate were investigated in Xenopus laevis oocytes. Our data demonstrate that in Xenopus oocytes expressing either OAT4 or OATP2B1 efflux of intracellular [14C]glutamate could be stimulated by conditions including extracellular glutamate (OAT4), estrone‐sulphate and bromosulphothalein (both OAT4 and OATP2B1) or pravastatin (OATP2B1). Cycling of glutamate across the placenta involving efflux via OAT4 and OATP2B1 and subsequent reuptake will drive placental uptake of organic anions from the fetal circulation.
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Affiliation(s)
- Emma M Lofthouse
- University of Southampton, Faculty of Medicine, Southampton General Hospital, Tremona Road, Southampton, UK
| | - Suzanne Brooks
- University of Southampton, Faculty of Medicine, Southampton General Hospital, Tremona Road, Southampton, UK
| | - Jane K Cleal
- University of Southampton, Faculty of Medicine, Southampton General Hospital, Tremona Road, Southampton, UK
| | - Mark A Hanson
- University of Southampton, Faculty of Medicine, Southampton General Hospital, Tremona Road, Southampton, UK
| | - Kirsten R Poore
- University of Southampton, Faculty of Medicine, Southampton General Hospital, Tremona Road, Southampton, UK
| | - Ita M O'Kelly
- University of Southampton, Faculty of Medicine, Southampton General Hospital, Tremona Road, Southampton, UK
| | - Rohan M Lewis
- University of Southampton, Faculty of Medicine, Southampton General Hospital, Tremona Road, Southampton, UK
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21
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Chen Z, He P, Ding X, Huang Y, Gu H, Ni X. PPARγ stimulates expression of L-type amino acid and taurine transporters in human placentas: the evidence of PPARγ regulating fetal growth. Sci Rep 2015; 5:12650. [PMID: 26227476 PMCID: PMC4521151 DOI: 10.1038/srep12650] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 07/06/2015] [Indexed: 12/17/2022] Open
Abstract
Placental amino acid transporters and peroxisome proliferator-activated receptors (PPARs) have been implicated to placental development and therefore regulation of fetal growth. We analyzed the correlation between the expression of amino acid transporters and PPARs and investigated whether PPARs control the expression of amino acid transporters in placentas. It was found that protein expression of PPARγ and L-type amino acid transporter 1(LAT1) and 2 (LAT2) was decreased in small-for-gestational-age (SGA) placentas. LAT1, LAT2 and taurine transporter (TAUT) expression correlated to PPARγ level and birth weight. In cultured placental cells, PPARγ agonist stimulated LAT1 and LAT2 and TAUT, which was reversed by PPARγ siRNA. PPARγ up-regulation of LAT1 and TAUT was through specificity protein 1 (Sp-1) while stimulation of LAT2 expression was via induction of gene transcription. Our data suggest that PPARγ, SP-1, LAT1 and LAT2 in placentas are involved in control of fetal growth. PPARγ signaling pathway may be the therapeutic target for intrauterine growth restriction.
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Affiliation(s)
- Zhaoguang Chen
- Department of Physiology, Second Military Medical University, Shanghai, China
| | - Ping He
- Department of Physiology, Second Military Medical University, Shanghai, China
| | - Xiaoying Ding
- Maternity and Child Health Hospital of Pudong New District, Shanghai, China
| | - Ying Huang
- Maternity and Child Health Hospital of Pudong New District, Shanghai, China
| | - Hang Gu
- Department of Obstetrics and Gynecology, Changhai Hospital, Shanghai, China
| | - Xin Ni
- Department of Physiology, Second Military Medical University, Shanghai, China
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22
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Lin G, Wang X, Wu G, Feng C, Zhou H, Li D, Wang J. Improving amino acid nutrition to prevent intrauterine growth restriction in mammals. Amino Acids 2015; 46:1605-23. [PMID: 24658999 DOI: 10.1007/s00726-014-1725-z] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Accepted: 03/06/2014] [Indexed: 12/18/2022]
Abstract
Intrauterine growth restriction (IUGR) is one of the most common concerns in human obstetrics and domestic animal production. It is usually caused by placental insufficiency, which decreases fetal uptake of nutrients (especially amino acids) from the placenta. Amino acids are not only building blocks for protein but also key regulators of metabolic pathways in fetoplacental development. The enhanced demands of amino acids by the developing conceptus must be met via active transport systems across the placenta as normal pregnancy advances. Growing evidence indicates that IUGR is associated with a reduction in placental amino acid transport capacity and metabolic pathways within the embryonic/fetal development. The positive relationships between amino acid concentrations in circulating maternal blood and placental amino acid transport into fetus encourage designing new therapies to prevent or treat IUGR by enhancing amino acid availability in maternal diets or maternal circulation. Despite the positive effects of available dietary interventions, nutritional therapy for IUGR is still in its infancy. Based on understanding of the underlying mechanisms whereby amino acids promote fetal growth and of their dietary requirements by IUGR, supplementation with functional amino acids (e.g., arginine and glutamine) hold great promise for preventing fetal growth restriction and improving health and growth of IUGR offspring.
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Widdows KL, Panitchob N, Crocker IP, Please CP, Hanson MA, Sibley CP, Johnstone ED, Sengers BG, Lewis RM, Glazier JD. Integration of computational modeling with membrane transport studies reveals new insights into amino acid exchange transport mechanisms. FASEB J 2015; 29:2583-94. [PMID: 25761365 PMCID: PMC4469330 DOI: 10.1096/fj.14-267773] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 02/18/2015] [Indexed: 01/25/2023]
Abstract
Uptake of system L amino acid substrates into isolated placental plasma membrane vesicles in the absence of opposing side amino acid (zero-trans uptake) is incompatible with the concept of obligatory exchange, where influx of amino acid is coupled to efflux. We therefore hypothesized that system L amino acid exchange transporters are not fully obligatory and/or that amino acids are initially present inside the vesicles. To address this, we combined computational modeling with vesicle transport assays and transporter localization studies to investigate the mechanisms mediating [14C]l-serine (a system L substrate) transport into human placental microvillous plasma membrane (MVM) vesicles. The carrier model provided a quantitative framework to test the 2 hypotheses that l-serine transport occurs by either obligate exchange or nonobligate exchange coupled with facilitated transport (mixed transport model). The computational model could only account for experimental [14C]l-serine uptake data when the transporter was not exclusively in exchange mode, best described by the mixed transport model. MVM vesicle isolates contained endogenous amino acids allowing for potential contribution to zero-trans uptake. Both L-type amino acid transporter (LAT)1 and LAT2 subtypes of system L were distributed to MVM, with l-serine transport attributed to LAT2. These findings suggest that exchange transporters do not function exclusively as obligate exchangers.—Widdows, K. L., Panitchob, N., Crocker, I. P., Please, C. P., Hanson, M. A., Sibley, C. P., Johnstone, E. D., Sengers, B. G., Lewis, R. M., Glazier, J. D. Integration of computational modeling with membrane transport studies reveals new insights into amino acid exchange transport mechanisms.
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Affiliation(s)
- Kate L Widdows
- *Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, Manchester, United Kingdom; St. Mary's Hospital and Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom; Mathematical Institute, Oxford University, Oxford, United Kingdom; and Faculty of Medicine, and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Nuttanont Panitchob
- *Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, Manchester, United Kingdom; St. Mary's Hospital and Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom; Mathematical Institute, Oxford University, Oxford, United Kingdom; and Faculty of Medicine, and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Ian P Crocker
- *Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, Manchester, United Kingdom; St. Mary's Hospital and Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom; Mathematical Institute, Oxford University, Oxford, United Kingdom; and Faculty of Medicine, and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Colin P Please
- *Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, Manchester, United Kingdom; St. Mary's Hospital and Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom; Mathematical Institute, Oxford University, Oxford, United Kingdom; and Faculty of Medicine, and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Mark A Hanson
- *Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, Manchester, United Kingdom; St. Mary's Hospital and Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom; Mathematical Institute, Oxford University, Oxford, United Kingdom; and Faculty of Medicine, and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Colin P Sibley
- *Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, Manchester, United Kingdom; St. Mary's Hospital and Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom; Mathematical Institute, Oxford University, Oxford, United Kingdom; and Faculty of Medicine, and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Edward D Johnstone
- *Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, Manchester, United Kingdom; St. Mary's Hospital and Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom; Mathematical Institute, Oxford University, Oxford, United Kingdom; and Faculty of Medicine, and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Bram G Sengers
- *Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, Manchester, United Kingdom; St. Mary's Hospital and Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom; Mathematical Institute, Oxford University, Oxford, United Kingdom; and Faculty of Medicine, and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Rohan M Lewis
- *Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, Manchester, United Kingdom; St. Mary's Hospital and Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom; Mathematical Institute, Oxford University, Oxford, United Kingdom; and Faculty of Medicine, and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Jocelyn D Glazier
- *Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, Manchester, United Kingdom; St. Mary's Hospital and Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom; Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom; Mathematical Institute, Oxford University, Oxford, United Kingdom; and Faculty of Medicine, and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
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Wu X, Xie C, Zhang Y, Fan Z, Yin Y, Blachier F. Glutamate-glutamine cycle and exchange in the placenta-fetus unit during late pregnancy. Amino Acids 2014; 47:45-53. [PMID: 25399054 DOI: 10.1007/s00726-014-1861-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 10/21/2014] [Indexed: 12/14/2022]
Abstract
The present review focuses on the physiological functions of glutamate-glutamine exchange involving placental amino acid transport and umbilical amino acid uptake in mammals (particularly in sows), with special emphasis on the associated regulating mechanisms. Glutamate plus glutamine are among the most abundant and the most utilized amino acids in fetus during late gestation. During pregnancy, amino acids, notably as precursors of macromolecules including proteins and nucleotides are involved in fetal development and growth. Amino acid concentrations in fetus are generally higher than in the mother. Among amino acids, the transport and metabolism of glutamate and glutamine during fetal development exhibit characteristics that clearly emphasize the importance of the interaction between the placenta and the fetal liver. Glutamate is quite remarkable among amino acids, which originate from the placenta, and is cleared from fetal plasma. In addition, the flux of glutamate through the placenta from the fetal plasma is highly correlated with the umbilical glutamate delivery rate. Glutamine plays a central role in fetal carbon and nitrogen metabolism and exhibits one of the highest fetal/maternal plasma ratio among all amino acids in human and other mammals. Glutamate is taken up by placenta from the fetal circulation and then converted to glutamine before being released back into the fetal circulation. Works are required on the glutamate-glutamine metabolism during late pregnancy in physiological and pathophysiological situations since such works may help to improve fetal growth and development both in humans and other mammals. Indeed, glutamine supplementation appears to ameliorate fetal growth retardation in sows and reduces preweaning mortality of piglets.
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Affiliation(s)
- Xin Wu
- Hunan Engineering and Research Center of Animal and Poultry Science, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, 410125, Changsha, China,
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25
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Computational modelling of amino acid exchange and facilitated transport in placental membrane vesicles. J Theor Biol 2014; 365:352-64. [PMID: 25451528 PMCID: PMC4271776 DOI: 10.1016/j.jtbi.2014.10.042] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 10/21/2014] [Accepted: 10/30/2014] [Indexed: 11/27/2022]
Abstract
Placental amino acid transport is required for fetal development and impaired transport has been associated with poor fetal growth. It is well known that placental amino acid transport is mediated by a broad array of specific membrane transporters with overlapping substrate specificity. However, it is not fully understood how these transporters function, both individually and as an integrated system. We propose that mathematical modelling could help in further elucidating the underlying mechanisms of how these transporters mediate placental amino acid transport. The aim of this work is to model the sodium independent transport of serine, which has been assumed to follow an obligatory exchange mechanism. However, previous amino acid uptake experiments in human placental microvillous plasma membrane vesicles have persistently produced results that are seemingly incompatible with such a mechanism; i.e. transport has been observed under zero-trans conditions, in the absence of internal substrates inside the vesicles to drive exchange. This observation raises two alternative hypotheses; (i) either exchange is not fully obligatory, or (ii) exchange is indeed obligatory, but an unforeseen initial concentration of amino acid substrate is present within the vesicle which could drive exchange. To investigate these possibilities, a mathematical model for tracer uptake was developed based on carrier mediated transport, which can represent either facilitated diffusion or obligatory exchange (also referred to as uniport and antiport mechanisms, respectively). In vitro measurements of serine uptake by placental microvillous membrane vesicles were carried out and the model applied to interpret the results based on the measured apparent Michaelis–Menten parameters Km and Vmax. In addition, based on model predictions, a new time series experiment was implemented to distinguish the hypothesised transporter mechanisms. Analysis of the results indicated the presence of a facilitated transport component, while based on the model no evidence for substantial levels of endogenous amino acids within the vesicle was found. Initial rate and time course data for serine uptake in placental membrane vesicles. Integrated model analysisof facilitative diffusion vs obligatory exchange. Dependency apparent Michaelis–Menten constants on internal concentrations. Uptake in placental vesicles was consistent with a facilitative transport component. No effects of any internal endogenous substrate in vesicles were apparent.
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Lewis RM, Demmelmair H, Gaillard R, Godfrey KM, Hauguel-de Mouzon S, Huppertz B, Larque E, Saffery R, Symonds ME, Desoye G. The placental exposome: placental determinants of fetal adiposity and postnatal body composition. ANNALS OF NUTRITION AND METABOLISM 2013; 63:208-15. [PMID: 24107818 DOI: 10.1159/000355222] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 08/19/2013] [Indexed: 11/19/2022]
Abstract
Offspring of obese and diabetic mothers are at increased risk of being born with excess adiposity as a consequence of their intrauterine environment. Excessive fetal fat accretion reflects additional placental nutrient transfer, suggesting an effect of the maternal environment on placental function. High plasma levels of particular nutrients in obese and diabetic mothers are likely to be the important drivers of nutrient transfer to the fetus, resulting in excess fat accretion. However, not all offspring of obese and diabetic mothers are born large for gestational age and the explanation may involve the regulation of placental nutrient transfer required for fetal growth. The placenta integrates maternal and fetal signals across gestation in order to determine nutrient transfer rate. Understanding the nature of these signals and placental responses to them is key to understanding the pathology of both fetal growth restriction and macrosomia. The overall effects of the maternal environment on the placenta are the product of its exposures throughout gestation, the 'placental exposome'. Understanding these environmental influences is important as exposures early in gestation, for instance causing changes in the function of genes involved in nutrient transfer, may determine how the placenta will respond to exposures later in gestation, such as to raised maternal plasma glucose or lipid concentrations. Longitudinal studies are required which allow investigation of the influences on the placenta across gestation. These studies need to make full use of developing technologies characterising placental function, fetal growth and body composition. Understanding these processes will assist in the development of preventive strategies and treatments to optimise prenatal growth in those pregnancies at risk of either excess or insufficient nutrient supply and could also reduce the risk of chronic disease in later life.
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Affiliation(s)
- R M Lewis
- University of Southampton, Southampton, UK
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27
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Day PE, Cleal JK, Lofthouse EM, Hanson MA, Lewis RM. What factors determine placental glucose transfer kinetics? Placenta 2013; 34:953-8. [PMID: 23886770 PMCID: PMC3776928 DOI: 10.1016/j.placenta.2013.07.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 07/03/2013] [Accepted: 07/05/2013] [Indexed: 10/26/2022]
Abstract
INTRODUCTION Transfer of glucose across the human placenta is directly proportional to maternal glucose concentrations even when these are well above the physiological range. This study investigates the relationship between maternal and fetal glucose concentrations and transfer across the placenta. METHODS Transfer of d-glucose, (3)H-3-o-methyl-d-glucose ((3)H-3MG) and (14)C-l-glucose across the isolated perfused human placental cotyledon was determined for maternal and fetal arterial d-glucose concentrations between 0 and 20 mmol/l. RESULTS Clearance of (3)H-3MG or (14)C-l-glucose was not affected by maternal or fetal d-glucose concentrations in either circulation. DISCUSSION Based on the arterial glucose concentrations and the reported KM for GLUT1, the transfer of d-glucose and (3)H-3MG would be expected to show signs of saturation as d-glucose concentrations increased but this did not occur. One explanation for this is that incomplete mixing of maternal blood and the rate of diffusion across unstirred layers may lower the effective concentration of glucose at the microvillous membrane and subsequently at the basal membrane. Uncertainties about the affinity of GLUT1 for glucose, both outside and inside the cell, may also contribute to the difference between the predicted and observed kinetics. CONCLUSION These factors may therefore help explain why the observed and predicted kinetics differ and they emphasise the importance of understanding the function of transport proteins in their physiological context. The development of a computational model of glucose transfer may improve our understanding of how the determinants of placental glucose transfer interact and function as a system.
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Affiliation(s)
- P E Day
- Institute of Developmental Sciences, University of Southampton, Faculty of Medicine, Southampton SO16 6YD, United Kingdom
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