1
|
Zaugg J, Albrecht C. Assessment of Placental Sodium-Independent Leucine Uptake and Transfer in Trophoblast Cells. Methods Mol Biol 2024; 2728:105-121. [PMID: 38019395 DOI: 10.1007/978-1-0716-3495-0_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
The placenta maintains the balance between nutrition and growth control of the fetus through selective and regulated supply of macronutrients such as carbohydrates, proteins, lipids, and critical micronutrients. Perturbations in the balanced supply of nutrients as found in gestational diseases and altered fetal development have been associated with changes in amino acid transport proteins, such as the System L amino acid heterodimeric exchangers LAT1/SLC7A5 and LAT2/SLC7A8. Syncytiotrophoblasts (STB) form the crucial cell layer at the placental barrier coordinating the transfer of essential amino acids such as leucine from the maternal to the fetal circulation. The System L-mediated leucine transport across the placental barrier is a Na+-independent process against a counter-directed gradient, maintained by a tightly regulated interplay between accumulative transporters, exchangers, and facilitators.The two methods described here allow to standardize and characterize the uptake kinetics of leucine in conventionally cultured BeWo cells and the transfer of leucine across the placental cell barrier using a BeWo monolayer in the Transwell® system.
Collapse
Affiliation(s)
- Jonas Zaugg
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Bern, Switzerland
- Swiss National Centre of Competence in Research (NCCR) TransCure, University of Bern, Bern, Switzerland
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Christiane Albrecht
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Bern, Switzerland.
- Swiss National Centre of Competence in Research (NCCR) TransCure, University of Bern, Bern, Switzerland.
| |
Collapse
|
2
|
Zhao J, Stewart ID, Baird D, Mason D, Wright J, Zheng J, Gaunt TR, Evans DM, Freathy RM, Langenberg C, Warrington NM, Lawlor DA, Borges MC. Causal effects of maternal circulating amino acids on offspring birthweight: a Mendelian randomisation study. EBioMedicine 2023; 88:104441. [PMID: 36696816 PMCID: PMC9879767 DOI: 10.1016/j.ebiom.2023.104441] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 12/28/2022] [Accepted: 01/06/2023] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Amino acids are key to protein synthesis, energy metabolism, cell signaling and gene expression; however, the contribution of specific maternal amino acids to fetal growth is unclear. METHODS We explored the effect of maternal circulating amino acids on fetal growth, proxied by birthweight, using two-sample Mendelian randomisation (MR) and summary data from a genome-wide association study (GWAS) of serum amino acids levels (sample 1, n = 86,507) and a maternal GWAS of offspring birthweight in UK Biobank and Early Growth Genetics Consortium, adjusting for fetal genotype effects (sample 2, n = 406,063 with maternal and/or fetal genotype effect estimates). A total of 106 independent single nucleotide polymorphisms robustly associated with 19 amino acids (p < 4.9 × 10-10) were used as genetic instrumental variables (IV). Wald ratio and inverse variance weighted methods were used in MR main analysis. A series of sensitivity analyses were performed to explore IV assumption violations. FINDINGS Our results provide evidence that maternal circulating glutamine (59 g offspring birthweight increase per standard deviation increase in maternal amino acid level, 95% CI: 7, 110) and serine (27 g, 95% CI: 9, 46) raise, while leucine (-59 g, 95% CI: -106, -11) and phenylalanine (-25 g, 95% CI: -47, -4) lower offspring birthweight. These findings are supported by sensitivity analyses. INTERPRETATION Our findings strengthen evidence for key roles of maternal circulating amino acids during pregnancy in healthy fetal growth. FUNDING A full list of funding bodies that contributed to this study can be found under Acknowledgments.
Collapse
Affiliation(s)
- Jian Zhao
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK; Bristol NIHR Biomedical Research Centre, Bristol, UK; Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK; The Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Institute of Early Life Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Maternal and Child Health, School of Public Health, Shanghai Jiao Tong University, Shanghai, China.
| | | | - Denis Baird
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK; Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Dan Mason
- Bradford Institute for Health Research, Bradford Teaching Hospitals National Health Service Foundation Trust, Bradford, UK
| | - John Wright
- Bradford Institute for Health Research, Bradford Teaching Hospitals National Health Service Foundation Trust, Bradford, UK
| | - Jie Zheng
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK; Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai Key Laboratory for Endocrine Tumor, State Key Laboratory of Medical Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Tom R Gaunt
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK; Bristol NIHR Biomedical Research Centre, Bristol, UK; Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - David M Evans
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK; University of Queensland Diamantina Institute, University of Queensland, Brisbane, QLD, Australia; Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Rachel M Freathy
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK; Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter, UK
| | - Claudia Langenberg
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK; Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Cambridge, UK; Computational Medicine, Berlin Institute of Health (BIH), Charité University Medicine, Berlin, Germany
| | - Nicole M Warrington
- University of Queensland Diamantina Institute, University of Queensland, Brisbane, QLD, Australia; Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia; K.G. Jebsen Center for Genetic Epidemiology, Department of Public Health and Nursing, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Deborah A Lawlor
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK; Bristol NIHR Biomedical Research Centre, Bristol, UK; Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Maria Carolina Borges
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK; Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| |
Collapse
|
3
|
Peng S, Li C, Xie X, Zhang X, Wang D, Lu X, Sun M, Meng T, Wang S, Jiang Y, Shan Z, Teng W. Divergence of Iodine and Thyroid Hormones in the Fetal and Maternal Parts of Human-Term Placenta. Biol Trace Elem Res 2020; 195:27-38. [PMID: 31502179 DOI: 10.1007/s12011-019-01834-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/11/2019] [Indexed: 01/29/2023]
Abstract
The human placenta is an important organ that forms a barrier where maternal and fetal exchange takes place. The placenta transport iodine to the fetal circulation by transfer of maternal iodine and deiodination of thyroid hormones (THs). The aim of the study was to examine the distribution of iodine and thyroid hormone transporters in the maternal and fetal sides of human-term placenta. A cross-sectional study was performed at the First Affiliated Hospital of China Medical University. Placental samples (maternal and fetal surfaces) were collected from 113 healthy-term pregnant women. The iodine content; the concentration of thyroxine (T4), triiodothyronine (T3), and reverse T3 (rT3); and the enzyme activity of placental type 2 iodothyronine deiodinase (D2) and D3 were examined. The mRNA and protein localization/expression of iodine and thyroid hormone transporters in the placenta were also studied. We also analyzed the association between expression level of Na+/I- symporter (NIS), thyroid hormone transporter protein, D3 activity in maternal and fetal surfaces of placenta with iodine content, and thyroid hormone levels. Iodine levels in placental samples from the maternal side were significantly higher than those in samples from the fetal side. T3 and T4 expression in fetal placenta was significantly lower than in maternal placenta. D3 activity in the fetal side of the placentas was significantly higher than that in the maternal side. The mRNA and protein expression of monocarboxylate transporters 8 (MCT8), L-amino acid transporters 1 (LAT1), organic anion transporting polypeptides 4A1 (OATP4A1), and TH binding protein transthyretin (TTR) were significantly increased in maternal side, while the NIS expression was higher in fetal side of human-term placenta. In conclusion, the enzymatic deiodination of thyroid hormones forms a barrier which reduces transplacental passage of the hormones and that the maternal part of the placenta is the primary factor in the mechanism regulating the hormonal transfer.
Collapse
Affiliation(s)
- Shiqiao Peng
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, China Medical University, Shenyang, 110001, Liaoning, People's Republic of China
| | - Chenyan Li
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, China Medical University, Shenyang, 110001, Liaoning, People's Republic of China
| | - Xiaochen Xie
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, China Medical University, Shenyang, 110001, Liaoning, People's Republic of China
| | - Xiaomei Zhang
- Department of Endocrinology and Metabolism, Peking University International Hospital, Haidian, Beijing, 100000, People's Republic of China
| | - Danyang Wang
- Department of Endocrinology and Metabolism, The First Hospital of Dandong, Dandong, 118000, Liaoning, People's Republic of China
| | - Xixuan Lu
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, China Medical University, Shenyang, 110001, Liaoning, People's Republic of China
| | - Manni Sun
- Department of Obstetrics, The First Affiliated Hospital of China Medical University, China Medical University, Shenyang, 110001, Liaoning, People's Republic of China
| | - Tao Meng
- Department of Obstetrics, The First Affiliated Hospital of China Medical University, China Medical University, Shenyang, 110001, Liaoning, People's Republic of China
| | - Shiwei Wang
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, China Medical University, Shenyang, 110001, Liaoning, People's Republic of China
| | - Yaqiu Jiang
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, China Medical University, Shenyang, 110001, Liaoning, People's Republic of China
| | - Zhongyan Shan
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, China Medical University, Shenyang, 110001, Liaoning, People's Republic of China
| | - Weiping Teng
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Affiliated Hospital of China Medical University, China Medical University, Shenyang, 110001, Liaoning, People's Republic of China.
| |
Collapse
|
4
|
Huang X, Anderle P, Hostettler L, Baumann MU, Surbek DV, Ontsouka EC, Albrecht C. Identification of placental nutrient transporters associated with intrauterine growth restriction and pre-eclampsia. BMC Genomics 2018; 19:173. [PMID: 29499643 PMCID: PMC5833046 DOI: 10.1186/s12864-018-4518-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 01/31/2018] [Indexed: 12/17/2022] Open
Abstract
Background Gestational disorders such as intrauterine growth restriction (IUGR) and pre-eclampsia (PE) are main causes of poor perinatal outcomes worldwide. Both diseases are related with impaired materno-fetal nutrient transfer, but the crucial transport mechanisms underlying IUGR and PE are not fully elucidated. In this study, we aimed to identify membrane transporters highly associated with transplacental nutrient deficiencies in IUGR/PE. Results In silico analyses on the identification of differentially expressed nutrient transporters were conducted using seven eligible microarray datasets (from Gene Expression Omnibus), encompassing control and IUGR/PE placental samples. Thereby 46 out of 434 genes were identified as potentially interesting targets. They are involved in the fetal provision with amino acids, carbohydrates, lipids, vitamins and microelements. Targets of interest were clustered into a substrate-specific interaction network by using Search Tool for the Retrieval of Interacting Genes. The subsequent wet-lab validation was performed using quantitative RT-PCR on placentas from clinically well-characterized IUGR/PE patients (IUGR, n = 8; PE, n = 5; PE+IUGR, n = 10) and controls (term, n = 13; preterm, n = 7), followed by 2D-hierarchical heatmap generation. Statistical evaluation using Kruskal-Wallis tests was then applied to detect significantly different expression patterns, while scatter plot analysis indicated which transporters were predominantly influenced by IUGR or PE, or equally affected by both diseases. Identified by both methods, three overlapping targets, SLC7A7, SLC38A5 (amino acid transporters), and ABCA1 (cholesterol transporter), were further investigated at the protein level by western blotting. Protein analyses in total placental tissue lysates and membrane fractions isolated from disease and control placentas indicated an altered functional activity of those three nutrient transporters in IUGR/PE. Conclusions Combining bioinformatic analysis, molecular biological experiments and mathematical diagramming, this study has demonstrated systematic alterations of nutrient transporter expressions in IUGR/PE. Among 46 initially targeted transporters, three significantly regulated genes were further investigated based on the severity and the disease specificity for IUGR and PE. Confirmed by mRNA and protein expression, the amino acid transporters SLC7A7 and SLC38A5 showed marked differences between controls and IUGR/PE and were regulated by both diseases. In contrast, ABCA1 may play an exclusive role in the development of PE. Electronic supplementary material The online version of this article (10.1186/s12864-018-4518-z) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Xiao Huang
- Swiss National Centre of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland.,Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Bern, Switzerland
| | - Pascale Anderle
- Swiss Institute of Bioinformatics and HSeT Foundation, Lausanne, Switzerland.,Sitem-insel AG, Bern, Switzerland
| | - Lu Hostettler
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Bern, Switzerland
| | - Marc U Baumann
- Swiss National Centre of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland.,Department of Obstetrics and Gynaecology, University Hospital, University of Bern, Bern, Switzerland
| | - Daniel V Surbek
- Swiss National Centre of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland.,Department of Obstetrics and Gynaecology, University Hospital, University of Bern, Bern, Switzerland
| | - Edgar C Ontsouka
- Swiss National Centre of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland.,Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Bern, Switzerland
| | - Christiane Albrecht
- Swiss National Centre of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland. .,Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Bern, Switzerland.
| |
Collapse
|
5
|
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: 1.4] [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.
Collapse
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
| |
Collapse
|
6
|
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: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [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.
Collapse
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.
| |
Collapse
|
7
|
Placental amino acid transport may be regulated by maternal vitamin D and vitamin D-binding protein: results from the Southampton Women's Survey. Br J Nutr 2015; 113:1903-10. [PMID: 25940599 PMCID: PMC4498463 DOI: 10.1017/s0007114515001178] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Both maternal 25-hydroxyvitamin D (25(OH)D) concentrations during pregnancy and
placental amino acid transporter gene expression have been associated with
development of the offspring in terms of body composition and bone structure.
Several amino acid transporter genes have vitamin D response elements in their
promoters suggesting the possible linkage of these two mechanisms. We aimed to
establish whether maternal 25(OH)D and vitamin D-binding protein (VDBP) levels
relate to expression of placental amino acid transporters. RNA was extracted
from 102 placental samples collected in the Southampton Women's Survey,
and gene expression was analysed using quantitative real-time PCR. Gene
expression data were normalised to the geometric mean of three housekeeping
genes, and related to maternal factors and childhood body composition. Maternal
serum 25(OH)D and VDBP levels were measured by radioimmunoassay. Maternal
25(OH)D and VDBP levels were positively associated with placental expression of
specific genes involved in amino acid transport. Maternal 25(OH)D and VDBP
concentrations were correlated with the expression of specific placental amino
acid transporters, and thus may be involved in the regulation of amino acid
transfer to the fetus. The positive correlation of VDBP levels and placental
transporter expression suggests that delivery of vitamin D to the placenta may
be important. This exploratory study identifies placental amino acid
transporters which may be altered in response to modifiable maternal factors and
provides a basis for further studies.
Collapse
|
8
|
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: 29] [Impact Index Per Article: 2.9] [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.
Collapse
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
| |
Collapse
|
9
|
Zhang S, Regnault TRH, Barker PL, Botting KJ, McMillen IC, McMillan CM, Roberts CT, Morrison JL. Placental adaptations in growth restriction. Nutrients 2015; 7:360-89. [PMID: 25580812 PMCID: PMC4303845 DOI: 10.3390/nu7010360] [Citation(s) in RCA: 157] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 12/22/2014] [Indexed: 12/17/2022] Open
Abstract
The placenta is the primary interface between the fetus and mother and plays an important role in maintaining fetal development and growth by facilitating the transfer of substrates and participating in modulating the maternal immune response to prevent immunological rejection of the conceptus. The major substrates required for fetal growth include oxygen, glucose, amino acids and fatty acids, and their transport processes depend on morphological characteristics of the placenta, such as placental size, morphology, blood flow and vascularity. Other factors including insulin-like growth factors, apoptosis, autophagy and glucocorticoid exposure also affect placental growth and substrate transport capacity. Intrauterine growth restriction (IUGR) is often a consequence of insufficiency, and is associated with a high incidence of perinatal morbidity and mortality, as well as increased risk of cardiovascular and metabolic diseases in later life. Several different experimental methods have been used to induce placental insufficiency and IUGR in animal models and a range of factors that regulate placental growth and substrate transport capacity have been demonstrated. While no model system completely recapitulates human IUGR, these animal models allow us to carefully dissect cellular and molecular mechanisms to improve our understanding and facilitate development of therapeutic interventions.
Collapse
Affiliation(s)
- Song Zhang
- Early Origins of Adult Health Research Group, Sansom Institute for Health Research, University of South Australia, Adelaide, SA 5001, Australia.
| | - Timothy R H Regnault
- Departments of Obstetrics and Gynecology, University of Western Ontario, London, ON N6A 5C1, Canada.
| | - Paige L Barker
- Early Origins of Adult Health Research Group, Sansom Institute for Health Research, University of South Australia, Adelaide, SA 5001, Australia.
| | - Kimberley J Botting
- Early Origins of Adult Health Research Group, Sansom Institute for Health Research, University of South Australia, Adelaide, SA 5001, Australia.
| | - Isabella C McMillen
- Early Origins of Adult Health Research Group, Sansom Institute for Health Research, University of South Australia, Adelaide, SA 5001, Australia.
| | - Christine M McMillan
- Early Origins of Adult Health Research Group, Sansom Institute for Health Research, University of South Australia, Adelaide, SA 5001, Australia.
| | - Claire T Roberts
- The Robinson Research Institute, University of Adelaide, Adelaide, SA 5005, Australia.
| | - Janna L Morrison
- Early Origins of Adult Health Research Group, Sansom Institute for Health Research, University of South Australia, Adelaide, SA 5001, Australia.
| |
Collapse
|
10
|
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: 23] [Impact Index Per Article: 2.1] [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.
Collapse
|
11
|
Hanson MA, Gluckman PD. Early developmental conditioning of later health and disease: physiology or pathophysiology? Physiol Rev 2014; 94:1027-76. [PMID: 25287859 PMCID: PMC4187033 DOI: 10.1152/physrev.00029.2013] [Citation(s) in RCA: 763] [Impact Index Per Article: 69.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Extensive experimental animal studies and epidemiological observations have shown that environmental influences during early development affect the risk of later pathophysiological processes associated with chronic, especially noncommunicable, disease (NCD). This field is recognized as the developmental origins of health and disease (DOHaD). We discuss the extent to which DOHaD represents the result of the physiological processes of developmental plasticity, which may have potential adverse consequences in terms of NCD risk later, or whether it is the manifestation of pathophysiological processes acting in early life but only becoming apparent as disease later. We argue that the evidence suggests the former, through the operation of conditioning processes induced across the normal range of developmental environments, and we summarize current knowledge of the physiological processes involved. The adaptive pathway to later risk accords with current concepts in evolutionary developmental biology, especially those concerning parental effects. Outside the normal range, effects on development can result in nonadaptive processes, and we review their underlying mechanisms and consequences. New concepts concerning the underlying epigenetic and other mechanisms involved in both disruptive and nondisruptive pathways to disease are reviewed, including the evidence for transgenerational passage of risk from both maternal and paternal lines. These concepts have wider implications for understanding the causes and possible prevention of NCDs such as type 2 diabetes and cardiovascular disease, for broader social policy and for the increasing attention paid in public health to the lifecourse approach to NCD prevention.
Collapse
Affiliation(s)
- M A Hanson
- Academic Unit of Human Development and Health, University of Southampton, and NIHR Nutrition Biomedical Research Centre, University Hospital, Southampton, United Kingdom; and Liggins Institute and Gravida (National Centre for Growth and Development), University of Auckland, Auckland, New Zealand
| | - P D Gluckman
- Academic Unit of Human Development and Health, University of Southampton, and NIHR Nutrition Biomedical Research Centre, University Hospital, Southampton, United Kingdom; and Liggins Institute and Gravida (National Centre for Growth and Development), University of Auckland, Auckland, New Zealand
| |
Collapse
|
12
|
Colicchia M, Campagnolo L, Baldini E, Ulisse S, Valensise H, Moretti C. Molecular basis of thyrotropin and thyroid hormone action during implantation and early development. Hum Reprod Update 2014; 20:884-904. [PMID: 24943836 DOI: 10.1093/humupd/dmu028] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Implantation and early embryo development are finely regulated processes in which several molecules are involved. Evidence that thyroid hormones (TH: T4 and T3) might be part of this machinery is emerging. An increased demand for TH occurs during gestation, and any alteration in maternal thyroid physiology has significant implications for both maternal and fetal health. Not only overt but also subclinical hypothyroidism is associated with infertility as well as with obstetric complications, including disruptions and disorders of pregnancy, labor, delivery, and troubles in early neonatal life. METHODS We searched the PubMed and Google Scholar databases for articles related to TH action on ovary, endometrium, trophoblast maturation and embryo implantation. In addition, articles on the regulation of TH activity at cellular level have been reviewed. The findings are hereby summarized and critically discussed. RESULTS TH have been shown to influence endometrial, ovarian and placental physiology. TH receptors (TR) and thyrotropin (thyroid-stimulating hormone: TSH) receptors (TSHR) are widely expressed in the feto-maternal unit during implantation, and both the endometrium and the trophoblast might be influenced by TH either directly or through TH effects on the synthesis and activity of implantation-mediating molecules. Interestingly, due to the multiplicity of mechanisms involved in TH action (e.g. differential expression of TR isoforms, heterodimeric receptor partners, interacting cellular proteins, and regulating enzymes), the TH concentration in blood is not always predictive of their cellular availability and activity at both genomic and nongenomic level. CONCLUSIONS In addition to the known role of TH on the hormonal milieu of the ovarian follicle cycle, which is essential for a woman's fertility, evidence is emerging on the importance of TH signaling during implantation and early pregnancy. Based on recent observations, a local action of TH on female reproductive organs and the embryo during implantation appears to be crucial for a successful pregnancy. Furthermore, an imbalance in the spatio-temporal expression of factors involved in TH activity might induce early arrest of pregnancy in women considered as euthyroid, based on their hormonal blood concentration. In conclusion, alterations of the highly regulated local activity of TH may play a crucial, previously underestimated, role in early pregnancy and pregnancy loss. Further studies elucidating this topic should be encouraged.
Collapse
Affiliation(s)
- Martina Colicchia
- Department of Systems' Medicine, University of Rome Tor Vergata, UOC of Endocrinology and Diabetes, Section of Reproductive Endocrinology Fatebenefratelli Hospital, 'Isola Tiberina' 00187, Rome, Italy
| | - Luisa Campagnolo
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Via Montpellier1, 00133 Rome, Italy
| | - Enke Baldini
- Department of Experimental Medicine, 'Sapienza' University of Rome, Rome, Italy
| | - Salvatore Ulisse
- Department of Experimental Medicine, 'Sapienza' University of Rome, Rome, Italy
| | - Herbert Valensise
- Department of Obstetrics and Gynaecology, University of Rome Tor Vergata, Fatebenefratelli Hospital 'Isola Tiberina', 00187 Rome, Italy
| | - Costanzo Moretti
- Department of Systems' Medicine, University of Rome Tor Vergata, UOC of Endocrinology and Diabetes, Section of Reproductive Endocrinology Fatebenefratelli Hospital, 'Isola Tiberina' 00187, Rome, Italy
| |
Collapse
|
13
|
Partitioning of glutamine synthesised by the isolated perfused human placenta between the maternal and fetal circulations. Placenta 2013; 34:1223-31. [PMID: 24183194 PMCID: PMC3851744 DOI: 10.1016/j.placenta.2013.10.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 09/03/2013] [Accepted: 10/07/2013] [Indexed: 01/01/2023]
Abstract
INTRODUCTION Placental glutamine synthesis has been demonstrated in animals and is thought to increase the availability of this metabolically important amino acid to the fetus. Glutamine is of fundamental importance for cellular replication, cellular function and inter-organ nitrogen transfer. The objective of this study was to investigate the role of glutamate/glutamine metabolism by the isolated perfused human placenta in the provision of glutamine to the fetus. METHODS Glutamate metabolism was investigated in the isolated dually perfused human placental cotyledon. U-¹³C-glutamate was used to investigate the movement of carbon and ¹⁵N-leucine to study movement of amino-nitrogen. Labelled amino acids were perfused via maternal or fetal arteries at defined flow rates. The enrichment and concentration of amino acids in the maternal and fetal veins were measured following 5 h of perfusion. RESULTS Glutamate taken up from the maternal and fetal circulations was primarily converted into glutamine the majority of which was released into the maternal circulation. The glutamine transporter SNAT5 was localised to the maternal-facing membrane of the syncytiotrophoblast. Enrichment of ¹³C or ¹⁵N glutamine in placental tissue was lower than in either the maternal or fetal circulation, suggesting metabolic compartmentalisation within the syncytiotrophoblast. DISCUSSION Placental glutamine synthesis may help ensure the placenta's ability to supply this amino acid to the fetus does not become limiting to fetal growth. Glutamine synthesis may also influence placental transport of other amino acids, metabolism, nitrogen flux and cellular regulation. CONCLUSIONS Placental glutamine synthesis may therefore be a central mechanism in ensuring that the human fetus receives adequate nutrition and is able to maintain growth.
Collapse
|
14
|
|
15
|
Regulation of nutrient transport across the placenta. J Pregnancy 2012; 2012:179827. [PMID: 23304511 PMCID: PMC3523549 DOI: 10.1155/2012/179827] [Citation(s) in RCA: 290] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 09/02/2012] [Indexed: 12/20/2022] Open
Abstract
Abnormal fetal growth, both growth restriction and overgrowth, is associated with perinatal complications and an increased risk of metabolic and cardiovascular disease later in life. Fetal growth is dependent on nutrient availability, which in turn is related to the capacity of the placenta to transport these nutrients. The activity of a range of nutrient transporters has been reported to be decreased in placentas of growth restricted fetuses, whereas at least some studies indicate that placental nutrient transport is upregulated in fetal overgrowth. These findings suggest that changes in placental nutrient transport may directly contribute to the development of abnormal fetal growth. Detailed information on the mechanisms by which placental nutrient transporters are regulated will therefore help us to better understand how important pregnancy complications develop and may provide a foundation for designing novel intervention strategies. In this paper we will focus on recent studies of regulatory mechanisms that modulate placental transport of amino acids, fatty acids, and glucose.
Collapse
|
16
|
Loubière LS, Vasilopoulou E, Glazier JD, Taylor PM, Franklyn JA, Kilby MD, Chan SY. Expression and function of thyroid hormone transporters in the microvillous plasma membrane of human term placental syncytiotrophoblast. Endocrinology 2012; 153:6126-35. [PMID: 23087173 PMCID: PMC4192285 DOI: 10.1210/en.2012-1753] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 09/12/2012] [Indexed: 11/19/2022]
Abstract
The transplacental passage of thyroid hormones (THs) from mother to fetus in humans has been deduced from observational clinical studies and is important for normal fetoplacental development. To investigate the transporters that regulate TH uptake by syncytiotrophoblast (the primary barrier to maternal-fetal exchange, which lies in direct contact with maternal blood), we isolated the microvillous plasma membrane (MVM) of human term syncytiotrophoblasts. We have demonstrated that MVM vesicles express plasma membrane TH transporter proteins, including system-L (L-type amino acid transporter 1 and CD98), monocarboxylate transporters (MCTs) 8 and 10, organic anion-transporting polypeptides 1A2 and 4A1. We provide the first definitive evidence that the human syncytiotrophoblast MVM is capable of rapid, saturable T(4) and T(3) uptake at similar rates and in a Na(+)-independent manner. These two major forms of THs could not significantly inhibit each others' uptake, suggesting that each is mediated by largely different transporters. No single transporter was noted to play a dominant role in either T(4) or T(3) uptake. Using combinations of transporter inhibitors that had an additive effect on TH uptake, we provide evidence that 67% of saturable T(4) uptake is facilitated by system-L and MCT10 with a minor role played by organic anion-transporting polypeptides, whereas 87% of saturable T(3) uptake is mediated by MCT8 and MCT10. Our data demonstrate that syncytiotrophoblast may control the quantity and forms of THs taken up by the human placenta. Thus, syncytiotrophoblast could be critical in regulating transplacental TH supply from the mother to the fetus.
Collapse
Affiliation(s)
- L S Loubière
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
17
|
Cleal JK, Glazier JD, Ntani G, Crozier SR, Day PE, Harvey NC, Robinson SM, Cooper C, Godfrey KM, Hanson MA, Lewis RM. Facilitated transporters mediate net efflux of amino acids to the fetus across the basal membrane of the placental syncytiotrophoblast. J Physiol 2011; 589:987-97. [PMID: 21224231 PMCID: PMC3060375 DOI: 10.1113/jphysiol.2010.198549] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 12/23/2010] [Indexed: 12/17/2022] Open
Abstract
Fetal growth depends on placental transfer of amino acids from maternal to fetal blood. The mechanisms of net amino acid efflux across the basal membrane (BM) of the placental syncytiotrophoblast to the fetus, although vital for amino acid transport, are poorly understood. We examined the hypothesis that facilitated diffusion by the amino acid transporters TAT1, LAT3 and LAT4 plays an important role in this process, with possible effects on fetal growth. Amino acid transfer was measured in isolated perfused human placental cotyledons (n = 5 per experiment) using techniques which distinguish between different transport processes. Placental TAT1, LAT3 and LAT4 proteins were measured, and mRNA expression levels (measured using real-time quantitative-PCR) were related to fetal and neonatal anthropometry and dual-energy X-ray absorptiometry measurements of neonatal lean mass in 102 Southampton Women's Survey (SWS) infants. Under conditions preventing transport by amino acid exchangers, all amino acids appearing in the fetal circulation were substrates of TAT1, LAT3 or LAT4. Western blots demonstrated the presence of TAT1, LAT3 and LAT4 in placental BM preparations. Placental TAT1 and LAT3 mRNA expression were positively associated with measures of fetal growth in SWS infants (P < 0.05). We provide evidence that the efflux transporters TAT1, LAT3 and LAT4 are present in the human placental BM, and may play an important role in the net efflux of amino acids to the fetus. Unlike other transporters they can increase fetal amino acid concentrations. Consistent with a role in placental amino acid transfer capacity and fetal growth TAT1 and LAT3 mRNA expression showed positive associations with infant size at birth.
Collapse
Affiliation(s)
- J K Cleal
- Institute of Developmental Sciences, University of Southampton, Mail point 887, Southampton General Hospital, Tremona Road, Southampton SO16 6YD, UK.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Tsitsiou E, Sibley CP, D’Souza SW, Catanescu O, Jacobsen DW, Glazier JD. Homocysteine is transported by the microvillous plasma membrane of human placenta. J Inherit Metab Dis 2011; 34:57-65. [PMID: 20567909 PMCID: PMC2966547 DOI: 10.1007/s10545-010-9141-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Revised: 04/01/2010] [Accepted: 05/31/2010] [Indexed: 12/18/2022]
Abstract
Elevated maternal plasma concentrations of homocysteine (Hcy) are associated with pregnancy complications and adverse neonatal outcomes. The postulate that we wish to advance here is that placental transport of Hcy, by competing with endogenous amino acids for transporter activity, may account for some of the damaging impacts of Hcy on placental metabolism and function as well as fetal development. In this article, we provide an overview of some recent studies characterising the transport mechanisms for Hcy across the microvillous plasma membrane (MVM) of the syncytiotrophoblast, the transporting epithelium of human placenta. Three Hcy transport systems have been identified, systems L, A and y(+)L. This was accomplished using a strategy of competitive inhibition to investigate the effects of Hcy on the uptake of well-characterised radiolabelled substrates for each transport system into isolated MVM vesicles. The reverse experiments were also performed, examining the effects of model substrates on [³⁵S]L-Hcy uptake. This article describes the evidence for systems L, A and y(+)L involvement in placental Hcy transport and discusses the physiological implications of these findings with respect to placental function and fetal development.
Collapse
Affiliation(s)
- Eleni Tsitsiou
- Maternal and Fetal Health Research Group, School of Biomedicine, University of Manchester, Manchester Academic Health Science Centre, St Mary’s Hospital, Oxford Road, Manchester M13 9WL, UK
| | - Colin P. Sibley
- Maternal and Fetal Health Research Group, School of Biomedicine, University of Manchester, Manchester Academic Health Science Centre, St Mary’s Hospital, Oxford Road, Manchester M13 9WL, UK
| | - Stephen W. D’Souza
- Maternal and Fetal Health Research Group, School of Biomedicine, University of Manchester, Manchester Academic Health Science Centre, St Mary’s Hospital, Oxford Road, Manchester M13 9WL, UK
| | - Otilia Catanescu
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Donald W. Jacobsen
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Jocelyn D. Glazier
- Maternal and Fetal Health Research Group, School of Biomedicine, University of Manchester, Manchester Academic Health Science Centre, St Mary’s Hospital, Oxford Road, Manchester M13 9WL, UK.
| |
Collapse
|
19
|
Rebuelto M, Loza ME. Antibiotic Treatment of Dogs and Cats during Pregnancy. Vet Med Int 2010; 2010:385640. [PMID: 21253497 PMCID: PMC3021871 DOI: 10.4061/2010/385640] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 08/24/2010] [Accepted: 11/02/2010] [Indexed: 01/16/2023] Open
Abstract
The use of pharmacological agents in pregnant females poses a major clinical challenge due to the marked physiological changes that may modify the pharmacokinetics of drugs and to the potential effects on the fetus. The purpose of this paper is to review briefly our knowledge on the use of antibacterial drugs during pregnancy and to provide information for the judicious selection of an antimicrobial treatment for use in pregnant bitches and queens. The risk to the fetus is a result of the ability of a drug to reach the fetal circulation and to produce toxic effects. The placenta functions as a barrier that protects the fetus due to the presence of transporters and metabolising enzymes; however, during pregnancy, the presence and activity of both enzymes and transporters may change. Antimicrobial agents that have been shown to be safe for use during pregnancy include betalactams, macrolides, and lincosamides. Pharmacotherapy during pregnancy in all species may affect adversely the developing fetus; therefore, it should be avoided when possible.
Collapse
Affiliation(s)
- Marcela Rebuelto
- Farmacología, Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Chorroarín 280, 1427 Buenos Aires, Argentina
| | | |
Collapse
|
20
|
Sengers BG, Please CP, Lewis RM. Computational modelling of amino acid transfer interactions in the placenta. Exp Physiol 2010; 95:829-40. [DOI: 10.1113/expphysiol.2010.052902] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
|
21
|
Brand A, Greenwood S, Glazier J, Bennett E, Godfrey K, Sibley C, Hanson M, Lewis R. Comparison of l-serine uptake by human placental microvillous membrane vesicles and placental villous fragments. Placenta 2010; 31:456-9. [DOI: 10.1016/j.placenta.2010.01.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 01/27/2010] [Accepted: 01/28/2010] [Indexed: 12/18/2022]
|
22
|
Lewis RM, Greenwood SL, Cleal JK, Crozier SR, Verrall L, Inskip HM, Cameron IT, Cooper C, Sibley CP, Hanson MA, Godfrey KM. Maternal muscle mass may influence system A activity in human placenta. Placenta 2010; 31:418-22. [PMID: 20206993 DOI: 10.1016/j.placenta.2010.02.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Revised: 01/28/2010] [Accepted: 02/01/2010] [Indexed: 11/28/2022]
Abstract
During pregnancy, nutrient partitioning between the mother and fetus must balance promoting fetal survival and maintaining nutritional status of the mother for her health and future fertility. The nutritional status of the pregnant woman, reflected in her body composition, may affect placental function with consequences for fetal development. We investigated the relationship between maternal body composition and placental system A amino acid transporter activity in 103 term placentas from Southampton Women's Survey pregnancies. Placental system A activity was measured as Na(+)-dependent uptake of 10 mumol/L (14)C-methylaminoisobutyric acid (a system A specific amino acid analogue) in placental villous fragments. Maternal body composition was measured at enrollment pre-pregnancy; in 45 infants neonatal body composition was measured using dual-energy x-ray absorptiometry. Term placental system A activity was lower in women with smaller pre-pregnancy upper arm muscle area (r = 0.27, P = 0.007), but was not related to maternal fat mass. System A activity was lower in mothers who reported undertaking strenuous exercise (24.6 vs 29.7 pmol/mg/15 min in sedentary women, P = 0.03), but was not associated with other maternal lifestyle factors. Lower placental system A activity in women who reported strenuous exercise and had a lower arm muscle area may reflect an adaptation in placental function which protects maternal resources in those with lower nutrient reserves. This alteration may affect fetal development, altering fetal body composition, with long-term consequences.
Collapse
Affiliation(s)
- R M Lewis
- Institute of Developmental Sciences, School of Medicine, University of Southampton, UK.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Expression of thyroid hormone transporters in the human placenta and changes associated with intrauterine growth restriction. Placenta 2010; 31:295-304. [DOI: 10.1016/j.placenta.2010.01.013] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 01/21/2010] [Accepted: 01/22/2010] [Indexed: 11/24/2022]
|
24
|
Enhanced serine production by bone metastatic breast cancer cells stimulates osteoclastogenesis. Breast Cancer Res Treat 2010; 125:421-30. [DOI: 10.1007/s10549-010-0848-5] [Citation(s) in RCA: 206] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Accepted: 03/13/2010] [Indexed: 12/23/2022]
|
25
|
Tsitsiou E, Sibley CP, D'Souza SW, Catanescu O, Jacobsen DW, Glazier JD. Homocysteine transport by systems L, A and y+L across the microvillous plasma membrane of human placenta. J Physiol 2009; 587:4001-13. [PMID: 19564394 PMCID: PMC2756434 DOI: 10.1113/jphysiol.2009.173393] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Accepted: 06/29/2009] [Indexed: 12/26/2022] Open
Abstract
Elevated maternal plasma levels of homocysteine (Hcy) are associated with pregnancy complications and adverse neonatal outcomes, suggesting placental transport of Hcy may impact on fetal development. However, such transport mechanisms have not been defined. In this study we characterise Hcy transport mechanisms across the microvillous plasma membrane (MVM) of the syncytiotrophoblast, the transporting epithelium of human placenta. Three candidate transport systems, systems L, A and y(+)L, were examined utilising competitive inhibition to investigate the effects of Hcy on the uptake of well-characterised radiolabelled substrates for each system into isolated MVM vesicles, and that of model substrates on 10 microm [(35)S]l-Hcy uptake. System L activity was inhibited by both l-Hcy and dl-Hcy, comparable to model substrates including 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid (BCH). System L constituted the major transport mechanism, with significant BCH inhibition (69%) of [(35)S]l-Hcy uptake. System A activity was also inhibited by l-Hcy and dl-Hcy with a smaller contribution (21%) to [(35)S]l-Hcy uptake. Inhibition by l-Hcy and dl-Hcy of system y(+)L activity was Na(+) sensitive with a significant inhibition constant (K(i)) shift observed following K(+) replacement; l-arginine reduced [(35)S]l-Hcy uptake by 19%. Kinetic modelling of [(35)S]l-Hcy uptake resolved two, Na(+)-independent, transport components (K(m) 72 microm and 9.7 mm). This study provides evidence for the involvement of systems L, A and y(+)L in placental Hcy transport. Such transport, by competing with endogenous amino acids for transporter activity, could have major implications for syncytiotrophoblast metabolism and function as well as fetal development.
Collapse
Affiliation(s)
- Eleni Tsitsiou
- Maternal and Fetal Health Research Group, University of Manchester, St Mary's Hospital, Hathersage Road, Manchester M13 0JH, UK
| | | | | | | | | | | |
Collapse
|
26
|
Abstract
The mechanisms by which amino acids are transferred across the human placenta are fundamental to our understanding of foetal nutrition. Amino acid transfer across the human placenta is dependent on transport across both the microvillous and basal plasma membranes of the placental syncytiotrophoblast, and on metabolism within the syncytiotrophoblast. Although the principles underlying uptake of amino acids across the microvillous plasma membrane are well understood, the extent to which amino acids are metabolised within human placenta and the mechanisms by which amino acids are transported out of the placenta across the basal plasma membrane are not well understood. Understanding the mechanisms and regulation of amino acid transport is necessary to understand the causes of intrauterine growth restriction in human pregnancy.
Collapse
Affiliation(s)
- J K Cleal
- The Institute of Developmental Sciences, University of Southampton, Southampton, UK.
| | | |
Collapse
|
27
|
Grillo MA, Lanza A, Colombatto S. Transport of amino acids through the placenta and their role. Amino Acids 2008; 34:517-23. [PMID: 18172742 DOI: 10.1007/s00726-007-0006-5] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Accepted: 11/13/2007] [Indexed: 01/01/2023]
Abstract
Amino acids are transported across the human placenta mediated by transporter proteins that differ in structure, mechanism and substrate specificity. Some of them are Na+-dependent systems, whereas others are Na+-independent. Among these there are transporters composed of a heavy chain, a glycoprotein, and a light chain. Moreover, they can be differently distributed in the two membranes forming the syncytiotrophoblast. The transport mechanisms involved and their regulation are only partially known. In the placenta itself, part of the amino acids is metabolized to form other compounds important for the fetus. This occurs for instance for arginine, which gives rise to polyamines and to NO. Interconversion occurs among few other amino acids Transport is altered in pregnancy complications, such as restricted fetal growth.
Collapse
Affiliation(s)
- M A Grillo
- Dipartimento di Medicina e Oncologia Sperimentale, Sezione di Biochimica, Università di Torino, Via Michelangelo 27, 10126 Torino, Italy.
| | | | | |
Collapse
|
28
|
Jones HN, Powell TL, Jansson T. Regulation of Placental Nutrient Transport – A Review. Placenta 2007; 28:763-74. [PMID: 17582493 DOI: 10.1016/j.placenta.2007.05.002] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Revised: 04/27/2007] [Accepted: 05/01/2007] [Indexed: 01/05/2023]
Abstract
Fetal growth is primarily determined by nutrient availability, which is intimately related to placental nutrient transport. Detailed information on the regulation of placental nutrient transporters is therefore critical in order to understand the mechanisms underlying altered fetal growth and fetal programming. After briefly summarizing the cellular mechanisms for placental transport of glucose, amino acids and free fatty acids, we will discuss factors shown to regulate placental nutrient transporters and review the data describing how these factors are altered in pregnancy complications associated with abnormal fetal growth. We propose an integrated model of regulation of placental nutrient transport by maternal and placental factors in IUGR.
Collapse
Affiliation(s)
- H N Jones
- Department of Obstetrics and Gynecology, University of Cincinnati, College of Medicine, 231 Albert B Sabin Way, Cincinnati, OH 45267, USA.
| | | | | |
Collapse
|
29
|
Cleal JK, Brownbill P, Godfrey KM, Jackson JM, Jackson AA, Sibley CP, Hanson MA, Lewis RM. Modification of fetal plasma amino acid composition by placental amino acid exchangers in vitro. J Physiol 2007; 582:871-82. [PMID: 17478537 PMCID: PMC2075319 DOI: 10.1113/jphysiol.2007.130690] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Accepted: 04/30/2007] [Indexed: 01/04/2023] Open
Abstract
Fetal growth is dependent on both the quantity and relative composition of amino acids delivered to the fetal circulation, and impaired placental amino acid supply is associated with restricted fetal growth. Amino acid exchangers can alter the composition, but not the quantity, of amino acids in the intra- and extracellular amino acid pools. In the placenta, exchangers may be important determinants of the amino acid composition in the fetal circulation. This study investigates the substrate specificity of exchange between the placenta and the feto-placental circulation. Maternal-fetal transfer of radiolabelled amino acids and creatinine were measured in the isolated perfused human placental cotyledon. Transfer of L-[14C]serine or L-[14C]leucine, and [3H]glycine, were measured in the absence of amino acids in the fetal circulation (transfer by non-exchange mechanisms) and following 10-20 micromol boluses of unlabelled amino acids into the fetal circulation to provide substrates for exchange (transfer by exchange and non-exchange mechanisms). The ability of fetal arterial boluses of L-alanine and L-leucine to stimulate release of amino acids from the placenta was also determined using HPLC in order to demonstrate the overall pattern of amino acid release. Experiments with radiolabelled amino acids demonstrated increased maternal-fetal transfer of L-serine and L-leucine, but not glycine, following boluses of specific amino acids into the fetal circulation. L-[14C]Leucine, but not L-[14C]serine or [3H]glycine, was transferred from the maternal to the fetal circulation by non-exchange mechanisms also (P<0.01). HPLC analysis demonstrated that fetal amino acid boluses stimulated increased transport of a range of different amino acids by 4-7 micromol l(-1) (P<0.05). Amino acid exchange provides a mechanism to supply the fetus with amino acids that it requires for fetal growth. This study demonstrates that these transporters have the capacity to exchange micromolar amounts of specific amino acids, and suggests that they play an important role in regulating fetal plasma amino acid composition.
Collapse
Affiliation(s)
- Jane K Cleal
- DOHaD Division, University of Southampton, Southampton, UK
| | | | | | | | | | | | | | | |
Collapse
|