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Yamashita M, Markert UR. Overview of Drug Transporters in Human Placenta. Int J Mol Sci 2021; 22:ijms222313149. [PMID: 34884954 PMCID: PMC8658420 DOI: 10.3390/ijms222313149] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 11/25/2021] [Accepted: 11/30/2021] [Indexed: 01/10/2023] Open
Abstract
The transport of drugs across the placenta is a point of great importance in pharmacotherapy during pregnancy. However, the knowledge of drug transport in pregnancy is mostly based on experimental clinical data, and the underlying biological mechanisms are not fully understood. In this review, we summarize the current knowledge of drug transporters in the human placenta. We only refer to human data since the placenta demonstrates great diversity among species. In addition, we describe the experimental models that have been used in human placental transport studies and discuss their availability. A better understanding of placental drug transporters will be beneficial for the health of pregnant women who need drug treatment and their fetuses.
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Affiliation(s)
- Michiko Yamashita
- Department of Obstetrics and Gynecology, Graduate School of Medicine, Osaka University, Osaka 5650871, Japan
- Placenta Lab, Department of Obstetrics, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany;
- Correspondence:
| | - Udo R. Markert
- Placenta Lab, Department of Obstetrics, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany;
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Anoshchenko O, Prasad B, Neradugomma NK, Wang J, Mao Q, Unadkat JD. Gestational Age-Dependent Abundance of Human Placental Transporters as Determined by Quantitative Targeted Proteomics. Drug Metab Dispos 2020; 48:735-741. [PMID: 32591415 PMCID: PMC7469251 DOI: 10.1124/dmd.120.000067] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 06/11/2020] [Indexed: 11/24/2022] Open
Abstract
Some women take medication during pregnancy to address a variety of clinical conditions. Because of ethical and logistical concerns, it is impossible to determine fetal drug exposure, and therefore fetal risk, during pregnancy. Hence, alternative approaches need to be developed to predict maternal-fetal drug exposure throughout pregnancy. To do so, we previously developed and verified a maternal-fetal physiologically based pharmacokinetic model, which can predict fetal exposure to drugs that passively cross the placenta. However, many drugs are actively transported by the placenta (e.g., human immunodeficiency virus protease inhibitors). To extend our maternal-fetal physiologically based pharmacokinetic model to these actively transported drugs, we determined the gestational age–dependent changes in the protein abundance of placental transporters. Total cellular membrane fractions from first trimester (T1; n = 15), second trimester (T2; n = 19), and term (n = 15) human placentae obtained from uncomplicated pregnancies were isolated by ultracentrifugation. Transporter protein abundance was determined by targeted quantitative proteomics using liquid chromatography tandem mass specrometry. We observed that breast cancer resistance protein and P-glycoprotein abundance significantly decreased from T1 to term by 55% and 69%, respectively (per gram of tissue). Organic anion–transporting polypeptide (OATP) 2B1 abundance significantly decreased from T1 to T2 by 32%. In contrast, organic cation transporter (OCT) 3 and organic anion transporter 4 abundance significantly increased with gestational age (2-fold from T1 to term, 1.6-fold from T2 to term). Serotonin transporter and norepinephrine transporter did not change with gestational age. The abundance of bile salt export pump, multidrug resistance-associated protein 1-5, Na+-taurocholate cotransporting polypeptide, OATP1B1, OATP1B3, OCTN1-2, concentrative nucleoside transporter 1-3, equilibrative nucleoside transporter 2, and multidrug and toxin extrusion 1 could not be quantified. These data can be incorporated into our maternal-fetal physiologically based pharmacokinetic model to predict fetal exposure to drugs that are actively transported across the placenta.
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Affiliation(s)
- Olena Anoshchenko
- Department of Pharmaceutics, University of Washington, Seattle, Washington
| | - Bhagwat Prasad
- Department of Pharmaceutics, University of Washington, Seattle, Washington
| | | | - Joanne Wang
- Department of Pharmaceutics, University of Washington, Seattle, Washington
| | - Qingcheng Mao
- Department of Pharmaceutics, University of Washington, Seattle, Washington
| | - Jashvant D Unadkat
- Department of Pharmaceutics, University of Washington, Seattle, Washington
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Afrouzian M, Al-Lahham R, Patrikeeva S, Xu M, Fokina V, Fischer WG, Abdel-Rahman SZ, Costantine M, Ahmed MS, Nanovskaya T. Role of the efflux transporters BCRP and MRP1 in human placental bio-disposition of pravastatin. Biochem Pharmacol 2018; 156:467-478. [PMID: 30217571 DOI: 10.1016/j.bcp.2018.09.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 09/10/2018] [Indexed: 12/11/2022]
Abstract
The expression and activity of human placental transporters during pregnancy could be altered by several factors including pathological changes associated with preeclampsia. The aims of this study were to identify the placental efflux transporters involved in the bio-disposition of pravastatin, determine the protein expression of these transporters and their encoding genes as well as the activity of pravastatin uptake in placentas obtained from patients with preeclampsia. ATP-dependent uptake of [3H]-pravastatin by trophoblast tissue apical and basal membrane vesicles exhibited sigmoidal kinetics. The curved shapes of Eadie-Hofstee plots indicate that more than one placental transporter are involved in the uptake of pravastatin. ATP-dependent uptake of [3H]-pravastatin into vesicles expressing MRP1-5, BCRP, and P-gp, as well as the results of inhibition studies suggest that BCRP and MRP1 are the major placental efflux transporters responsible for the in vitro uptake of pravastatin. Compared to placentas from healthy pregnancies, preeclamptic placentas had increased number of syncytial knots with increased expression of BCRP in their apical membrane and increased expression of MRP1 in the cytoplasm of the syncytiotrophoblast and in cytoplasm of syncytial knots. There was a concomitant increase in ABCC1 but not in ABCG2 gene expressions in preeclamptic placentas. ATP-dependent uptake of [3H]-pravastatin by vesicles prepared from apical membranes of preeclamptic placentas was similar to the uptake by vesicles prepared from placentas obtained after uncomplicated pregnancies (13.9 ± 6.5 vs 14.1 ± 5.8 pmol·mg protein-1 min-1). The transporter-specific changes in the expression of BCRP and MRP1 in preeclamptic placentas did not affect the efflux activity of transporters localized on the apical membrane of the syncytiotrophoblast.
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Affiliation(s)
- Marjan Afrouzian
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Rabab Al-Lahham
- Maternal-Fetal Pharmacology and Bio-Development Laboratories, Department of Obstetrics & Gynecology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Svetlana Patrikeeva
- Maternal-Fetal Pharmacology and Bio-Development Laboratories, Department of Obstetrics & Gynecology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Meixiang Xu
- Maternal-Fetal Pharmacology and Bio-Development Laboratories, Department of Obstetrics & Gynecology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Valentina Fokina
- Maternal-Fetal Pharmacology and Bio-Development Laboratories, Department of Obstetrics & Gynecology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Wayne G Fischer
- Department of Qulity Management & Patient Safety, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Sherif Z Abdel-Rahman
- Maternal-Fetal Pharmacology and Bio-Development Laboratories, Department of Obstetrics & Gynecology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Maged Costantine
- Maternal-Fetal Pharmacology and Bio-Development Laboratories, Department of Obstetrics & Gynecology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Mahmoud S Ahmed
- Maternal-Fetal Pharmacology and Bio-Development Laboratories, Department of Obstetrics & Gynecology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Tatiana Nanovskaya
- Maternal-Fetal Pharmacology and Bio-Development Laboratories, Department of Obstetrics & Gynecology, University of Texas Medical Branch, Galveston, TX 77555, USA.
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Settle P, Sibley CP, Doughty IM, Johnston T, Glazier JD, Powell TL, Jansson T, D'Souza SW. Placental Lactate Transporter Activity and Expression in Intrauterine Growth Restriction. ACTA ACUST UNITED AC 2016; 13:357-63. [PMID: 16814165 DOI: 10.1016/j.jsgi.2006.04.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2006] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To compare lactate uptake in the microvillous plasma membrane (maternal facing [MVM]) in term and preterm placentas in intrauterine growth restriction (IUGR) and appropriate weight for gestational age (AGA) controls, and in the basal plasma membrane (fetal facing [BM]) at term. In addition, we examine the expression of monocarboxylate transporters (MCT1 and MCT4). METHODS We measured [14C] L-lactate uptakes into vesicles prepared from MVM and BM, stimulated by an inwardly directed H+ gradient. MCT expression was examined by Western blotting. RESULTS In term placentas, mean (+/- SE) [14C] L-lactate uptake into MVM vesicles of the IUGR (n = 6) and AGA (n = 11) groups at initial rate was similar (15.4 +/- 2.3 versus 15.0 +/- 1.1 pmol/mg protein/20 s). In preterm placentas, in IUGR (n = 3) and AGA (n = 3) groups, [14C] l-lactate uptake into MVM was also not significantly different. In BM vesicles from term placentas, [14C] L-lactate uptake was significantly lower in IUGR (n = 5) than in AGA (n = 6) controls (3.6 +/- 0.4 versus 5.6 +/- 0.6 pmol/mg protein/20 s, P <.05). MCT1 and MCT4 were expressed in BM vesicles, but there was no difference in expression between the IUGR and AGA groups. CONCLUSIONS These findings suggest that in IUGR placental lactate transport capacity in the BM is reduced, which may adversely affect placental lactate clearance.
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Affiliation(s)
- Paul Settle
- Division of Human Development, University of Manchester, St. Mary's Hospital, Manchester, United Kingdom
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Oh SY, Hwang JR, Lee Y, Choi SJ, Kim JS, Kim JH, Sadovsky Y, Roh CR. Isolation of basal membrane proteins from BeWo cells and their expression in placentas from fetal growth-restricted pregnancies. Placenta 2016; 39:24-32. [DOI: 10.1016/j.placenta.2016.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 12/10/2015] [Accepted: 01/03/2016] [Indexed: 10/22/2022]
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Tomi M, Eguchi H, Ozaki M, Tawara T, Nishimura S, Higuchi K, Maruyama T, Nishimura T, Nakashima E. Role of OAT4 in Uptake of Estriol Precursor 16α-Hydroxydehydroepiandrosterone Sulfate Into Human Placental Syncytiotrophoblasts From Fetus. Endocrinology 2015; 156:2704-12. [PMID: 25919187 DOI: 10.1210/en.2015-1130] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Estriol biosynthesis in human placenta requires the uptake of a fetal liver-derived estriol precursor, 16α-hydroxydehydroepiandrosterone sulfate (16α-OH DHEAS), by placental syncytiotrophoblasts at their basal plasma membrane (BM), which faces the fetal circulation. The aim of this work is to identify the transporter(s) mediating 16α-OH DHEAS uptake at the fetal side of syncytiotrophoblasts by using human placental BM-enriched vesicles and to examine the contribution of the putative transporter to estriol synthesis at the cellular level, using choriocarcinoma JEG-3 cells. Organic anion transporter (OAT)-4 and organic anion transporting polypeptide 2B1 proteins were enriched in human placental BM vesicles compared with crude membrane fraction. Uptake of [(3)H]16α-OH DHEAS by BM vesicles was partially inhibited in the absence of sodium but was significantly increased in the absence of chloride and after preloading glutarate. Uptake of [(3)H]16α-OH DHEAS by BM vesicles was significantly inhibited by OAT4 substrates such as dehydroepiandrosterone sulfate, estrone-3-sulfate, and bromosulfophthalein but not by cyclosporin A, tetraethylammonium, p-aminohippuric acid, or cimetidine. These characteristics of vesicular [(3)H]16α-OH DHEAS uptake are in good agreement with those of human OAT4-transfected COS-7 cells as well as forskolin-differentiated JEG-3 cells. Estriol secretion from differentiated JEG-3 cells was detected when the cells were incubated with 16α-OH DHEAS for 8 hours but was inhibited in the presence of 50 μM bromosulfophthalein. Our results indicate that OAT4 at the BM of human placental syncytiotrophoblasts plays a predominant role in the uptake of 16α-OH DHEAS for placental estriol synthesis.
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Affiliation(s)
- Masatoshi Tomi
- Faculty of Pharmacy (M.T., H.E., M.O., T.T., S.N., K.H., T.N., E.N.), Keio University, Minato-ku 105-8512, Tokyo, Japan; School of Pharmaceutical Sciences (K.H.), Teikyo University, Itabashi-ku 173-8605, Tokyo, Japan; and Department of Obstetrics and Gynecology (T.M.), School of Medicine, Keio University, Shinjuku-ku 160-8512, Tokyo, Japan
| | - Hiromi Eguchi
- Faculty of Pharmacy (M.T., H.E., M.O., T.T., S.N., K.H., T.N., E.N.), Keio University, Minato-ku 105-8512, Tokyo, Japan; School of Pharmaceutical Sciences (K.H.), Teikyo University, Itabashi-ku 173-8605, Tokyo, Japan; and Department of Obstetrics and Gynecology (T.M.), School of Medicine, Keio University, Shinjuku-ku 160-8512, Tokyo, Japan
| | - Mayuko Ozaki
- Faculty of Pharmacy (M.T., H.E., M.O., T.T., S.N., K.H., T.N., E.N.), Keio University, Minato-ku 105-8512, Tokyo, Japan; School of Pharmaceutical Sciences (K.H.), Teikyo University, Itabashi-ku 173-8605, Tokyo, Japan; and Department of Obstetrics and Gynecology (T.M.), School of Medicine, Keio University, Shinjuku-ku 160-8512, Tokyo, Japan
| | - Tomohiro Tawara
- Faculty of Pharmacy (M.T., H.E., M.O., T.T., S.N., K.H., T.N., E.N.), Keio University, Minato-ku 105-8512, Tokyo, Japan; School of Pharmaceutical Sciences (K.H.), Teikyo University, Itabashi-ku 173-8605, Tokyo, Japan; and Department of Obstetrics and Gynecology (T.M.), School of Medicine, Keio University, Shinjuku-ku 160-8512, Tokyo, Japan
| | - Sachika Nishimura
- Faculty of Pharmacy (M.T., H.E., M.O., T.T., S.N., K.H., T.N., E.N.), Keio University, Minato-ku 105-8512, Tokyo, Japan; School of Pharmaceutical Sciences (K.H.), Teikyo University, Itabashi-ku 173-8605, Tokyo, Japan; and Department of Obstetrics and Gynecology (T.M.), School of Medicine, Keio University, Shinjuku-ku 160-8512, Tokyo, Japan
| | - Kei Higuchi
- Faculty of Pharmacy (M.T., H.E., M.O., T.T., S.N., K.H., T.N., E.N.), Keio University, Minato-ku 105-8512, Tokyo, Japan; School of Pharmaceutical Sciences (K.H.), Teikyo University, Itabashi-ku 173-8605, Tokyo, Japan; and Department of Obstetrics and Gynecology (T.M.), School of Medicine, Keio University, Shinjuku-ku 160-8512, Tokyo, Japan
| | - Tetsuo Maruyama
- Faculty of Pharmacy (M.T., H.E., M.O., T.T., S.N., K.H., T.N., E.N.), Keio University, Minato-ku 105-8512, Tokyo, Japan; School of Pharmaceutical Sciences (K.H.), Teikyo University, Itabashi-ku 173-8605, Tokyo, Japan; and Department of Obstetrics and Gynecology (T.M.), School of Medicine, Keio University, Shinjuku-ku 160-8512, Tokyo, Japan
| | - Tomohiro Nishimura
- Faculty of Pharmacy (M.T., H.E., M.O., T.T., S.N., K.H., T.N., E.N.), Keio University, Minato-ku 105-8512, Tokyo, Japan; School of Pharmaceutical Sciences (K.H.), Teikyo University, Itabashi-ku 173-8605, Tokyo, Japan; and Department of Obstetrics and Gynecology (T.M.), School of Medicine, Keio University, Shinjuku-ku 160-8512, Tokyo, Japan
| | - Emi Nakashima
- Faculty of Pharmacy (M.T., H.E., M.O., T.T., S.N., K.H., T.N., E.N.), Keio University, Minato-ku 105-8512, Tokyo, Japan; School of Pharmaceutical Sciences (K.H.), Teikyo University, Itabashi-ku 173-8605, Tokyo, Japan; and Department of Obstetrics and Gynecology (T.M.), School of Medicine, Keio University, Shinjuku-ku 160-8512, Tokyo, Japan
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Noguchi S, Nishimura T, Fujibayashi A, Maruyama T, Tomi M, Nakashima E. Organic Anion Transporter 4-Mediated Transport of Olmesartan at Basal Plasma Membrane of Human Placental Barrier. J Pharm Sci 2015; 104:3128-35. [PMID: 25820021 DOI: 10.1002/jps.24434] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/02/2015] [Accepted: 03/03/2015] [Indexed: 12/11/2022]
Abstract
Mechanisms regulating fetal transfer of olmesartan, an angiotensin-II receptor type 1 antagonist, are important as potential determinants of life-threatening adverse fetal effects. The purpose of this study was to examine the olmesartan transport mechanism through the basal plasma membrane (BM) of human syncytiotrophoblasts forming the placental barrier. Uptake of olmesartan by human placental BM vesicles was potently inhibited by dehydroepiandrosterone sulfate (DHEAS), estrone 3-sulfate, and bromosulfophthalein, which are all typical substrates of organic anion transporter (OAT) 4 localized at the BM of syncytiotrophoblasts, and was increased in the absence of chloride. In tetracycline-inducible OAT4-expressing cells, [(3) H]olmesartan uptake was increased by tetracycline treatment. Olmesartan uptake via OAT4 was concentration dependent with a Km of 20 μM, and was increased in the absence of chloride. [(3) H]Olmesartan efflux via OAT4 was also observed and was trans-stimulated by extracellular chloride and DHEAS. Thus, OAT4 mediates bidirectional transport of olmesartan and appears to regulate fetal transfer of olmesartan at the BM of syncytiotrophoblasts. Efflux transport of olmesartan via OAT4 from syncytiotrophoblasts to the fetal circulation might be facilitated in the presence of an inwardly directed physiological chloride gradient and extracellular DHEAS.
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Affiliation(s)
- Saki Noguchi
- Faculty of Pharmacy, Keio University, Minato-ku, Tokyo, 105-8512, Japan
| | | | - Ayasa Fujibayashi
- Faculty of Pharmacy, Keio University, Minato-ku, Tokyo, 105-8512, Japan
| | - Tetsuo Maruyama
- Department of Obstetrics and Gynecology, School of Medicine, Keio University, Shinjuku-ku, Tokyo, 160-8512, Japan
| | - Masatoshi Tomi
- Faculty of Pharmacy, Keio University, Minato-ku, Tokyo, 105-8512, Japan
| | - Emi Nakashima
- Faculty of Pharmacy, Keio University, Minato-ku, Tokyo, 105-8512, Japan
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Boyd C. Review: Epithelial aspects of human placental trophoblast. Placenta 2013; 34 Suppl:S24-6. [DOI: 10.1016/j.placenta.2012.11.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 11/13/2012] [Accepted: 11/15/2012] [Indexed: 11/25/2022]
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Shennan DB. Placental sulphate transport: a review of functional and molecular studies. Placenta 2012; 33:599-603. [PMID: 22578714 DOI: 10.1016/j.placenta.2012.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 04/11/2012] [Accepted: 04/12/2012] [Indexed: 10/28/2022]
Abstract
Sulphate is required by the feto-placental unit for a number of important conjugation and biosynthetic pathways. Functional studies performed several decades ago established that sulphate transport in human placental microvillus and basal membrane vesicles was mainly via a DIDS-sensitive anion-exchange mechanism. In contrast, no evidence was found for Na⁺-dependent transport. Studies performed using isolated human placental tissue confirmed anion-exchange as the main mechanism. More recently, molecular studies have established the presence of anion-exchange proteins which could play a role in transplacental sulphate movement. However, the presence of transcripts for NaS2 has been reported and has prompted the suggestion that Na⁺-sulphate cotransport may play an important role in maternal-fetal sulphate transport. This article reviews our present knowledge of placental sulphate transport, both functional and molecular, and attempts to form a model based on the available evidence.
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Azzaroli F, Mennone A, Feletti V, Simoni P, Baglivo E, Montagnani M, Rizzo N, Pelusi G, DE Aloysio D, Lodato F, Festi D, Colecchia A, Roda E, Boyer JL, Mazzella G. Clinical trial: modulation of human placental multidrug resistance proteins in cholestasis of pregnancy by ursodeoxycholic acid. Aliment Pharmacol Ther 2007; 26:1139-46. [PMID: 17894656 DOI: 10.1111/j.1365-2036.2007.03462.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND The effects of ursodeoxycholic acid on human placental bile acids and bilirubin transporters in intrahepatic cholestasis of pregnancy are still undefined. AIM To evaluate whether ursodeoxycholic acid affects MRP2, MRP3 and MRP4 expression in the placenta. MATERIALS AND METHODS Forty-three pregnant women were enrolled; fourteen subjects had physiological pregnancies. Intrahepatic cholestasis of pregnancy patients were divided into two groups: (i) 13 received ursodeoxycholic acid (20 mg/kg/day) and (ii) 16 untreated. Total bile acid and bilirubin in serum and cord blood were determined in each subject. Multidrug resistance proteins expression (immunoblot, quantitative real-time PCR) was evaluated in placentas collected at delivery. anova test was used for statistical analysis of data. RESULTS Ursodeoxycholic acid administration significantly improved maternal serum bile acid and cord blood bilirubin and bile acid levels. MRP2 protein and RNA expression was significantly increased in placentas from treated patients compared to controls (P < 0.001 and P < 0.01, respectively). MRP3 protein expression was not significantly different between the groups while RNA expression was significantly decreased in treated patients (P < 0.01). MRP4 did not show significant differences between the groups. CONCLUSIONS Ursodeoxycholic acid administration induces placental MRP2 expression, and reduces bilirubin and bile acid levels in cord blood.
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Affiliation(s)
- F Azzaroli
- Dipartimento di Medicina Interna e Gastroenterologia, Università degli Studi di Bologna, Bologna, Italy/
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Fant M, Barerra-Saldana H, Dubinsky W, Poindexter B, Bick R. The PLAC1 protein localizes to membranous compartments in the apical region of the syncytiotrophoblast. Mol Reprod Dev 2007; 74:922-9. [PMID: 17186554 DOI: 10.1002/mrd.20673] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
PLAC1 is a trophoblast-specific gene that maps to a locus on the X-chromosome important to placental development. We have previously shown that PLAC1 gene expression is linked to trophoblast differentiation. The objective of this study was to define the localization of the PLAC1 polypeptide as a prerequisite to understanding its function. Polyclonal antibodies specific for the putative PLAC1 polypeptide were generated. The subcellular localization of PLAC1 in the trophoblast was examined by immunohistochemical analysis of human placenta complemented by immunoblot analysis of subcellular fractions. Brightfield immunohistochemical analysis of placental tissue indicated that the PLAC1 protein localizes to the differentiated syncytiotrophoblast in the apical region of the cell. Deconvlution immunofluorescence microscopy confirmed localization to the apical region of the syncytiotrophoblast. Its distribution included both intracellular compartments as well as loci in close association with the maternal-facing, microvillous brush border membrane (MVM). These findings were supported by immunoblot analysis of subcellular fractions. A 30 kDa band was associated with the microsomal fraction of placental lysates but not the mitochondrial, nuclear, or soluble fractions, suggesting PLAC1 is targeted to a membrane location. Plasma membranes were obtained from the fetal-facing, basal surface (BM) and the maternal-facing, MVM of the syncytiotrophoblast membrane. PLAC1 immunoreactivity was only detected in membrane fractions derived from the apical MVM consistent with immunohistochemical analyses. These data demonstrate that the PLAC1 protein is restricted primarily to the differentiated trophoblast, localizing to intracellular membranous compartment(s) in the apical region of the syncytiotrophoblast and associated with its apical, microvillous membrane surface.
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Affiliation(s)
- Michael Fant
- Department of Pediatrics, University of Texas Health Science Center, Houston, Texas 77030, USA.
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Sata R, Ohtani H, Tsujimoto M, Murakami H, Koyabu N, Nakamura T, Uchiumi T, Kuwano M, Nagata H, Tsukimori K, Nakano H, Sawada Y. Functional analysis of organic cation transporter 3 expressed in human placenta. J Pharmacol Exp Ther 2005; 315:888-95. [PMID: 16081676 DOI: 10.1124/jpet.105.086827] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of this study is to investigate the placental transport mechanism of cationic compounds by comparison of the uptake of an organic cation into human placental basal membrane vesicles (BLMVs) with that into organic cation transporter 3 (OCT3)-expressing cells. Reverse transcription-polymerase chain reaction analysis demonstrated that OCT3 is the only OCT isoform expressed in the human placenta. The function of OCT3 was investigated by measuring the uptake of 1-methyl-4-phenylpyridinium (MPP(+)) into human embryonic kidney (HEK)293 cells stably expressing OCT3 (HEK/OCT3 cells). The OCT3-mediated uptake of MPP(+) was sodium- and chloride-independent and saturable, with a Michaelis constant (K(m)) of 82.5 microM. The OCT3-mediated uptake was inhibited by various cationic drugs in a concentration-dependent manner but not by anionic compounds, such as p-aminohippuric acid and captopril, or a zwitterion, carnitine. Western blotting analysis of membrane vesicles prepared from human term placenta revealed that OCT3 is expressed only in BLMVs but not in microvillous membrane vesicles. The uptake of MPP(+) into BLMVs was membrane potential-dependent and saturable, with a K(m) value of 51.8 muM, which is similar to that in HEK293/OCT3 cells. The inhibitory spectrum of various compounds on MPP(+) uptake by BLMVs was also similar to that in HEK293/OCT3 cells. These results suggest that OCT3 is expressed on the basal membrane of human trophoblast cells and plays an important role in the placental transport of cationic compounds.
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Affiliation(s)
- Ryoko Sata
- Department of Medico-Pharmaceutical Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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Speake PF, Mynett KJ, Glazier JD, Greenwood SL, Sibley CP. Activity and expression of Na+/H+ exchanger isoforms in the syncytiotrophoblast of the human placenta. Pflugers Arch 2005; 450:123-30. [PMID: 15772858 DOI: 10.1007/s00424-005-1382-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Accepted: 01/03/2005] [Indexed: 11/26/2022]
Abstract
The purpose of this study was to compare Na+/H+ exchanger (NHE) activity in the microvillous (MVM) and basal (BM) plasma membrane of the human placental syncytiotrophoblast and to determine the relative contribution of various NHE isoforms to this activity. Uptake of 22Na into isolated MVM vesicles in the presence of a H+ gradient, at initial rate, was four- to fivefold higher than that by BM vesicles (214+/-28 vs. 49+/-9 pmol/mg protein per 30 s, respectively, means+/-SEM, n=8, 6, P<0.001). The 22Na uptake by MVM, but not by BM, was reduced in the absence of a H+ gradient and in the presence of 500 microM amiloride. To determine the contribution of NHE1, NHE2 and NHE3 isoforms to NHE activity in MVM, we investigated the effect of amiloride analogues which show isoform selectivity. HOE 694, an analogue selective for NHE1 at low concentrations, inhibited 22Na uptake with an EC50 of 0.13+/-0.05 microM (n=6), whereas S3226, an analogue selective for NHE3 at low concentrations had an EC50 of 3.01+/-0.85 microM (n=5). To investigate this further, we measured recovery of syncytiotrophoblast intracellular pH (pHi) from an acid load using a H+-selective, fluorescent dye (BCECF) loaded into isolated intact placental fragments. This recovery was blocked in the absence of Na+ and the presence of amiloride (500 microM) and concentrations of HOE 694 and S3226 were comparable to those used in vesicle experiments. Overall these data show that under the conditions used NHE activity in the term placental syncytiotrophoblast is absent from BM. NHE activity in the MVM is attributable predominantly to NHE1.
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Affiliation(s)
- P F Speake
- Human Development and Reproductive Health Academic Group, Academic Unit of Child Health, University of Manchester, St. Mary's Hospital, Hathersage Road, Manchester, M13 OJH, UK.
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15
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Meyer Zu Schwabedissen HEU, Grube M, Heydrich B, Linnemann K, Fusch C, Kroemer HK, Jedlitschky G. Expression, localization, and function of MRP5 (ABCC5), a transporter for cyclic nucleotides, in human placenta and cultured human trophoblasts: effects of gestational age and cellular differentiation. THE AMERICAN JOURNAL OF PATHOLOGY 2005; 166:39-48. [PMID: 15631998 PMCID: PMC1602292 DOI: 10.1016/s0002-9440(10)62230-4] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The placenta functions both as site for nutrition and protection of the fetus. Transport proteins, including members of the multidrug resistance protein (MRP)/ABCC subfamily, have been recognized to contribute to the latter function. MRP5 (ABCC5) was identified as transmembrane transport protein for cyclic nucleotides, especially 3',5'-cyclic GMP (cGMP), indicating an additional role in signal transduction and a potential role in placenta development. We therefore studied expression, localization, and function of MRP5 in placenta of different gestational ages. Quantitative real-time polymerase chain reaction revealed expression of MRP5 in all 60 samples from pre-term and term placenta, with a decreasing mean expression with gestational age (MRP5/18S-ratio x 1000; < 32 weeks: 2.91 +/- 0.73, n = 15; 32 to 37 weeks: 2.10 +/- 0.87, n = 15; > 37 weeks: 0.46 +/- 0.08, n = 30; P < 0.01). Immunofluorescence microscopy with an anti-MRP5 antibody indicated localization of MRP5 preferentially in the basal membrane of syncytiotrophoblasts and in and around fetal vessels. ATP-dependent [(3)H]cGMP transport as evidence for MRP5 function could be demonstrated in isolated basal membrane vesicles. Moreover, the influence of cellular differentiation on MRP5 expression was studied in isolated trophoblasts, revealing an increase of the MRP5 expression in parallel with the hCG production (MRP5/18S-ratio x 1000 was 2.4 +/- 0.5 at day 5 of culture and 1.45 +/- 0.5 at day 0 of culture, n = 3 preparations, significant difference with P < 0.05). In conclusion, MRP5 expression depends on gestational age and varies throughout the differentiation process. In view of the important role of cGMP for cellular differentiation, MRP5 may play a role in placental development in context with a specific need for cellular cGMP export.
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16
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Settle P, Mynett K, Speake P, Champion E, Doughty IM, Sibley CP, D'Souza SW, Glazier J. Polarized lactate transporter activity and expression in the syncytiotrophoblast of the term human placenta. Placenta 2004; 25:496-504. [PMID: 15135232 DOI: 10.1016/j.placenta.2003.11.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2003] [Revised: 11/21/2003] [Accepted: 11/24/2003] [Indexed: 10/26/2022]
Abstract
We investigated the polarization of l-lactate transport in human syncytiotrophoblast by measuring uptake of [(14)C] l-lactate by both microvillous (maternal-facing; MVM) and basal (fetal-facing; BM) plasma membranes. [(14)C] l-lactate uptake by MVM and BM was stimulated in the presence of an inwardly directed H(+)gradient, with a significantly higher uptake in MVM than in BM at initial rate (15.4+/-2.3 vs 5.6+/-0.6 pmol/mg protein/20 sec). Stereospecific inhibition was observed in MVM, with a higher affinity for l-lactate compared with d-lactate. In BM, there was no difference in the inhibition by these two stereoisomers. Inhibition of lactate uptake in both MVM and BM by 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), an inhibitor of monocarboxylate transporter (MCT) activity, indicated MCT-mediated mechanisms across both membranes. Kinetic modelling supported a two-transporter model as the best fit for both MVM and BM, the K(m)of the major component being 6.21 mm and 25.01 mm in MVM and BM respectively. Western blotting and immunolocalization examining the distribution of MCT1 and MCT4, showed that MCT expression was polarized, MCT1 being predominantly localized to BM and MCT4 showing greater abundance on MVM. CD147, a chaperone protein for MCT1 and MCT4, was equally expressed by both membranes. These studies demonstrate that the opposing plasma membranes of human syncytiotrophoblast are polarized with respect to both MCT activity and expression.
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Affiliation(s)
- P Settle
- Academic Unit of Child Health, St Mary's Hospital, University of Manchester, Hathersage Road, Manchester M13 0JH, UK
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17
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Grube M, Meyer Zu Schwabedissen H, Draber K, Präger D, Möritz KU, Linnemann K, Fusch C, Jedlitschky G, Kroemer HK. EXPRESSION, LOCALIZATION, AND FUNCTION OF THE CARNITINE TRANSPORTER OCTN2 (SLC22A5) IN HUMAN PLACENTA. Drug Metab Dispos 2004; 33:31-7. [PMID: 15486076 DOI: 10.1124/dmd.104.001560] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
L-carnitine is assumed to play an important role in fetal development, and there is evidence that carnitine is transported across the placenta. The protein involved in this transfer, however, has not been identified on a molecular level. We therefore characterized localization and function of the carnitine transporter OCTN2 in human placenta. Significant expression of OCTN2 mRNA was detected in human placenta applying real-time polymerase chain reaction technology. Confocal immunofluorescence microscopy using an antibody directed against the carboxy terminus of OCTN2 protein revealed that it is predominantly expressed in the apical membrane of syncytiotrophoblasts. This was confirmed by the costaining of organic anion-transporting polypeptide B and MRP2, which are known to be expressed mainly in the basal and apical syncytiotrophoblasts membrane, respectively. To further support this finding, we performed transport studies using basal and apical placenta membrane vesicles. We could demonstrate that the carnitine uptake into the apical vesicles was about eight times higher compared with the basal ones. Moreover, this uptake was sodium- and pH-dependent with an apparent K(m) value of 21 muM and inhibited by verapamil, which is in line with published data for recombinant OCTN2. Finally, experiments using trophoblasts in cell culture revealed that expression of OCTN2 paralleled human choriogonadotropin production and thus is modulated by cellular differentiation. In summary, we show expression and function of OCTN2 in human placenta. Moreover, several lines of evidence indicate that OCTN2 is localized in the apical membrane of syncytiotrophoblasts, thereby suggesting a major role in the uptake of carnitine during fetal development.
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Affiliation(s)
- Markus Grube
- Department of Pharmacology, Friedrich Loefflerstr. 23d, 17487 Greifswald, Germany
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18
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Jimenez V, Henriquez M, Llanos P, Riquelme G. Isolation and Purification of Human Placental Plasma Membranes from Normal and Pre-eclamptic Pregnancies. A Comparative Study. Placenta 2004; 25:422-37. [PMID: 15081637 DOI: 10.1016/j.placenta.2003.10.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2003] [Revised: 10/15/2003] [Accepted: 10/28/2003] [Indexed: 11/20/2022]
Abstract
Human placental syncytiotrophoblast is the main barrier for materno-fetal exchange. Analysis of transplacental transport involves the study of ion channels in both the maternal-facing microvillous membrane (MVM) and the fetal-facing basal membrane (BM). Difficulties in having access to intact placenta with conventional electrophysiological methods favour alternative methodologies, such as isolation and reconstitution of membranes in artificial lipid systems. Pre-eclampsia is a major health problem of human pregnancy. The search for altered physiological processes in pre-eclamptic placentae requires the investigation of events at both the microvillous and basal surfaces. The aim of this study was to obtain reliable syncytiotrophoblast plasma membranes from human normal (N) and pre-eclamptic (PE) pregnancies. We describe a protocol which allows for the simultaneous isolation of MVM and BM. The purity of the membranes isolated was evaluated using enzymatic assays, binding studies, Western blotting and immunohistochemistry. Enrichment of alkaline phosphatase activity for MVM was 17 to 21-fold, with 13-16 per cent protein recovery, for both N and PE. Enrichment of adenylate cyclase activity for BM was 9-fold for N, and enrichment of dihydroalprenolol binding to beta-adrenergic receptors was 12-fold for N and 6-fold for PE, with 14 per cent protein recovery for both N and PE. Cross contamination was low and mitochondrial membrane contamination was negligible. We conclude that MVM and BM isolated from placentae of pre-eclamptic women are similar in enrichment and purity to those of healthy women, thus allowing their use in comparative electrophysiological studies.
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Affiliation(s)
- V Jimenez
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Casilla 70005, Santiago 7, Chile
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19
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Nagashige M, Ushigome F, Koyabu N, Hirata K, Kawabuchi M, Hirakawa T, Satoh S, Tsukimori K, Nakano H, Uchiumi T, Kuwano M, Ohtani H, Sawada Y. Basal Membrane Localization of MRP1 in Human Placental Trophoblast. Placenta 2003; 24:951-8. [PMID: 14580377 DOI: 10.1016/s0143-4004(03)00170-x] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The placental trophoblast is considered to act as a barrier between mother and fetus, mediating the exchange of various materials across the placenta. ATP-binding cassette (ABC) transporters such as P-glycoprotein (P-gp) and multidrug-resistance protein (MRP) are expressed in the placenta and function as efflux transport systems for xenobiotics. In the present study, we aimed to determine the localization of MRP1 in the human placenta in comparison with that of P-gp. Western blotting analysis with human placental membrane vesicles indicated that P-gp and MRP1 are localized on the brush-border membranes and basal membranes, respectively. Immunohistochemical analysis with human normal full-term placenta showed that anti-P-gp monoclonal antibody F4 stained the brush-border side of the trophoblast cells, whereas anti-MRP1 monoclonal antibody MRPr1 stained the basal side. These results confirm that P-gp and MRP1 are located on the brush-border membranes and basal membranes, respectively, of human full-term placental trophoblast. MRP1 was also detected on the abluminal side of blood vessels in the villi. Accordingly, MRP1 may play a role distinct from that of P-gp, which is considered to restrict the influx of xenobiotics into the fetus.
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Affiliation(s)
- M Nagashige
- Department of Medico-Pharmaceutical Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, 812-8582 Fukuoka, Japan
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20
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Pascolo L, Fernetti C, Pirulli D, Crovella S, Amoroso A, Tiribelli C. Effects of maturation on RNA transcription and protein expression of four MRP genes in human placenta and in BeWo cells. Biochem Biophys Res Commun 2003; 303:259-65. [PMID: 12646196 DOI: 10.1016/s0006-291x(03)00327-9] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The placenta is a multifunctional organ that protects the fetus from toxic compounds and the MRPs contribute to this function. The expression of MRP1, MRP2, MRP3, and MRP5 was compared in human placental tissue and in BeWo cells by real-time RT-PCR analysis; protein expression was assessed by Western blot. MRP1 and MRP3 were the most abundantly expressed genes in placenta but only MRP1 was highly expressed in the BeWo cells. Expression of MRP1 increased 4-fold in the third as compared with first trimester placental samples, and increased 20-fold with polarization of BeWo cells. MRP2, MRP3, and MRP5 were weakly expressed both in placenta and BeWo cells. Protein expression followed mRNA quantification for MRP1 and MRP5 but not for MRP2 and MRP3. These data indicated that MRP1 and MRP5 increase with trophoblast maturation, suggesting a particular role for these proteins in the organ functional development.
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Affiliation(s)
- Lorella Pascolo
- Centro Studi Fegato at AREA Science Park and Dipartimento BBCM, Universitá di Trieste, Trieste, Italy.
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21
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Ushigome F, Koyabu N, Satoh S, Tsukimori K, Nakano H, Nakamura T, Uchiumi T, Kuwano M, Ohtani H, Sawada Y. Kinetic analysis of P-glycoprotein-mediated transport by using normal human placental brush-border membrane vesicles. Pharm Res 2003; 20:38-44. [PMID: 12608534 DOI: 10.1023/a:1022290523347] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE P-Glycoprotein (Pgp) plays an important role in drug disposition and excretion in various tissues such as the brain, intestine, and kidney. Moreover, we have demonstrated that Pgp is expressed on the brush-border membranes of trophoblast cells in the placenta and restricts drug transfer from the maternal circulation to the fetus. However, the transport kinetics of physiologically expressed Pgp has scarcely been investigated. METHODS In this study, we assessed the functional kinetics of transport mediated by Pgp that is physiologically expressed in normal tissue by using human placental brush-border membrane vesicles (BBMVs). Digoxin and vinblastine were used as typical substrates of Pgp. RESULTS The uptakes of [3H]digoxin and [3H]vinblastine into BBMVs were significantly increased in the presence of an ATP-regenerating system. The ATP-dependent uptakes of [3H]digoxin and [3H]vinblastine into BBMVs exhibited saturable kinetics. The Michaelis constants (Kt values) were 2.65 +/- 1.80 microM and 21.9 +/- 3.37 microM, respectively. In the presence of a Pgp inhibitor such as verapamil, cyclosporine A, or progesterone, the ATP-dependent uptakes of [3H]digoxin and [3H]vinblastine into BBMVs were significantly reduced. Anti-Pgp monoclonal antibody C219 completely inhibited the uptake of [3H]digoxin. CONCLUSIONS The transport kinetics of [3H]digoxin and [3H]vinblastine by physiologically expressed Pgp were successfully evaluated by using BBMVs prepared from normal human placenta. The present method enabled us to evaluate the function of physiologically expressed Pgp and is superior to the use of cultured transfectants in terms of the yield of vesicles. The present method may also be applicable to investigating the influence of various factors such as the genotype of the MDR1 gene or various pathophysiologic states of neonates on the function of Pgp.
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Affiliation(s)
- Fumihiko Ushigome
- Department of Medico-Pharmaceutical Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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22
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Inuyama M, Ushigome F, Emoto A, Koyabu N, Satoh S, Tsukimori K, Nakano H, Ohtani H, Sawada Y. Characteristics of L-lactic acid transport in basal membrane vesicles of human placental syncytiotrophoblast. Am J Physiol Cell Physiol 2002; 283:C822-30. [PMID: 12176739 DOI: 10.1152/ajpcell.00545.2001] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The characteristics of L-lactic acid transport across the trophoblast basal membrane were investigated and compared with those across the brush-border membrane by using membrane vesicles isolated from human placenta. The uptake of L-[(14)C]lactic acid into basal membrane vesicles was Na(+) independent, and an uphill transport was observed in the presence of a pH gradient ([H(+)](out) > [H(+)](in)). L-[(14)C]lactic acid uptake exhibited saturation kinetics with a K(m) value of 5.89 +/- 0.68 mM in the presence of a pH gradient. p-Chloromercuribenzenesulfonate and alpha-cyano-4-hydroxycinnamate inhibited the initial uptake, whereas phloretin or 4,4'-diisothiocyanostilbene-2,2'-disulfonate did not. Mono- and dicarboxylic acids suppressed the initial uptake. In conclusion, L-lactic acid transport in the basal membrane is H(+) dependent and Na(+) independent, as is also the case for the brush-border membrane transport, and its characteristics resemble those of monocarboxylic acid transporters. However, there were several differences in the effects of inhibitors between basal and brush-border membrane vesicles, suggesting that the transporter(s) involved in L-lactic acid transport in the basal membrane of placental trophoblast may differ from those in the brush-border membrane.
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Affiliation(s)
- Masako Inuyama
- Department of Medico-Pharmaceutical Sciences, Graduate School of Pharmaceutical Sciences, Higashi-ku, Fukuoka 812-8582, Japan
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23
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Serrano MA, Bayón JE, Pascolo L, Tiribelli C, Ostrow JD, Gonzalez-Gallego J, Marin JJG. Evidence for carrier-mediated transport of unconjugated bilirubin across plasma membrane vesicles from human placental trophoblast. Placenta 2002; 23:527-35. [PMID: 12175967 DOI: 10.1053/plac.2002.0838] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Unconjugated bilirubin (UCB) is currently believed to cross the placenta only by passive diffusion. To assess whether carrier-mediated transport might be involved, the uptake of [(3)H]-UCB by basal (bTPM) and apical (aTPM) plasma membrane vesicles from human placental trophoblast at term was investigated. In both types of vesicles, the uptake of [(3)H]-UCB into an osmotically sensitive space was temperature-dependent, independent of the presence of Na(+), and not affected by changes in membrane potential. The uptake of [(3)H]-UCB by aTPM, but not bTPM, was activated by ATP hydrolysis and inhibited by vanadate. Thus, the exact contribution of both inside out and right-side out bTPM to UCB uptake could not be distinguished, while only inverted aTPM were expected to carry out ATP-dependent UCB uptake. In bTPM and aTPM, uptake of free (unbound) [(3)H]-UCB (B(f)) consisted of a dominant, saturable, presumably carrier-mediated process and a diffusional component that became predominant only at B(f) near or above aqueous solubility limit for UCB (70 nM ). For bTPM, K(m)=7.2 nM; V(max)=9.8 pmol/20s/mg protein; and diffusion coefficient (K(D))=0.14 ml/20s/mg protein. For aTPM in the presence of 9.5m M ATP, K(m)=18 n M; V(max)=131 pmol/20s/mg protein; and K(D)=0.47 ml/20s/mg protein. The uptake of [(3)H]-UCB by bTPM was cis-inhibited by estrone-3-sulfate and estradiol-17 beta-glucuronide and trans-stimulated by unlabelled UCB and bromosulphopthalein. ATP-dependent UCB uptake by aTPM was cis-inhibited by doxorubicin, cholic acid, methotrexate and pronenecid. These findings suggest the presence of distinct transporters in the two domains of human placental trophoblast that could cooperate to transfer UCB from the foetus to the maternal circulation.
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Affiliation(s)
- M A Serrano
- Department of Biochemistry and Molecular Biology, University of Salamanca, Campus Miguel de Unamuno, ED-128, 37007-Salamanca, Spain
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24
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Cramer S, Beveridge M, Kilberg M, Novak D. Physiological importance of system A-mediated amino acid transport to rat fetal development. Am J Physiol Cell Physiol 2002; 282:C153-60. [PMID: 11742808 DOI: 10.1152/ajpcell.2002.282.1.c153] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fetal growth and development are dependent on the delivery of amino acids from maternal amino acid pools to the fetal blood. This is accomplished via transfer across the apical and basal plasma membrane of the placental syncytiotrophoblast. The aim of this study was to determine whether inhibition of system A (amino acid transporter) was associated with a decrease in fetal weight in the rat. System A is a ubiquitous Na(+)-dependent amino acid transporter that actively transports small zwitterionic amino acids. In brief, system A was inhibited by infusing a nonmetabolizable synthetic amino acid analog, 2-(methylamino)isobutyric acid from days 7-20 of gestation. On day 20, the rats were killed and tissues (maternal liver, fetuses, and placentas) were collected for analysis. The degree of system A inhibition was determined, as was the impact of said inhibition on fetal and maternal weights, system A-mediated placental transport, and placental system A-mediated transporter expression. Our results suggest that when system A is inhibited, fetal weight is diminished [control group: -3.55 +/- 0.04 g (n = 113), experimental group: -3.29 +/- 0.04 g (n = 128)], implying an integral role for system A transport in fetal growth and development in the rat.
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Affiliation(s)
- Stuart Cramer
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, Florida 32610, USA
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25
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Pepe GJ, Burch MG, Albrecht ED. Estrogen regulates 11 beta-hydroxysteroid dehydrogenase-1 and -2 localization in placental syncytiotrophoblast in the second half of primate pregnancy. Endocrinology 2001; 142:4496-503. [PMID: 11564715 DOI: 10.1210/endo.142.10.8434] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We recently demonstrated that the 11 beta-hydroxysteroid dehydrogenase enzymes catalyzing cortisol-cortisone reduction (11 beta-hydroxysteroid dehydrogenase-1) and oxidation (11 beta-hydroxysteroid dehydrogenase-2) are located in different regions of the baboon and human placental syncytiotrophoblast. Moreover, there was a 2-fold increase in the ratio of 11 beta-hydroxysteroid dehydrogenase-2 to 11 beta-hydroxysteroid dehydrogenase-1 in syncytiotrophoblast membranes contiguous with the basal membrane (BMm) between mid and late baboon gestation. Our laboratories have also shown that estrogen regulates syncytiotrophoblast functional differentiation. Therefore, the current study determined whether the change in the ratio of 11 beta-hydroxysteroid dehydrogenase-2 to 11 beta-hydroxysteroid dehydrogenase-1 in the BMm was regulated by estrogen. Placentas were obtained on d 165 of gestation (term = d 184) from baboons that were untreated or were treated daily beginning on d 100 with the aromatase inhibitor CGS 20267, which reduced uterine and maternal serum E2 by more than 95% or with CGS 20267 plus E2 benzoate. Western blot analyses and immunofluorescence confirmed that in untreated controls the expression of 11 beta-hydroxysteroid dehydrogenase-1 was abundant in the microvillus membranes and considerably less in the BMm. In contrast, expression of 11 beta-hydroxysteroid dehydrogenase-2 was abundant in more internal regions of the syncytiotrophoblast, including the BMm, but was not detected in the microvillus membranes. The 11 beta-hydroxysteroid dehydrogenase-2 protein level was significantly decreased in the BMm of placentas from estrogen-suppressed baboons, resulting in a 2-fold decrease in the ratio of these enzymes in membranes juxta the fetal blood, and these changes were partially restored by CGS 20267 and E2. In contrast, estrogen had no effect on the ratio of 11 beta-hydroxysteroid dehydrogenase-2 to 11 beta-hydroxysteroid dehydrogenase-1 in whole villous homogenate or the micro-villus membranes. Collectively, these results indicate that estrogen regulates the developmental increase in the ratio of 11 beta-hydroxysteroid dehydrogenase-2 to 11 beta-hydroxysteroid dehydrogenase-1 in syncytiotrophoblast membranes juxta fetal blood, providing the subcellular architectural mechanism responsible for the previously demonstrated estrogen-dependent switch in transplacental glucocorticoid metabolism that regulates maturation of the primate fetal pituitary-adrenocortical axis.
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Affiliation(s)
- G J Pepe
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia 23507, USA.
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26
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Kudo Y, Boyd CA. Characterisation of L-tryptophan transporters in human placenta: a comparison of brush border and basal membrane vesicles. J Physiol 2001; 531:405-16. [PMID: 11230513 PMCID: PMC2278476 DOI: 10.1111/j.1469-7793.2001.0405i.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The mechanisms responsible for L-tryptophan transport at both the maternal- and fetal-facing surfaces of the term placenta have been determined in isolated membrane vesicles as part of a study on placental indoleamine 2,3-dioxygenase, the L-tryptophan-catabolising enzyme recently shown to regulate feto-maternal immunology. Brush border vesicle uptake of L-tryptophan is substantially into an osmotically active space. It is sodium independent and N-ethylmaleimide sensitive. Uptake of L-tryptophan, which is markedly stereospecific, has a Km of 26.3 microM and Vmax of 1.72 pmol (mg protein)(-1) s(-1) and is completely abolished by the L-system-specific substrate 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH). These findings are in keeping with L-tryptophan transport being exclusively via system L (induced by the heterodimeric heavy chain of CD98 and system L-amino acid transporter-1 (LAT-1)). 1-Methyl-tryptophan (which is a known competitive inhibitor of indoleamine 2,3-dioxygenase) is a competitive inhibitor of L-tryptophan flux through this transport system (Ki = 113 microM). Basal membrane transport of L-tryptophan is more complex. Uptake is slower than at the brush border and although, as in the brush border, uptake is sodium independent, it is less sensitive to N-ethylmaleimide. There is clear evidence that two systems contribute to basal membrane transport since BCH is (in sodium-free media) only a partial inhibitor whereas L-histidine and L-cysteine are fully effective. The simplest explanation of these and other findings is that the basal membrane possesses two systems, one of which is similar to that induced by the heavy chain of CD98 and system L-amino acid transporter-2 (LAT-2). The other appears to be system y+L since in the presence of BCH inhibition by L-leucine but not by L-lysine is sodium dependent. These findings suggest the existence of non-identical carrier-mediated transport systems for L-tryptophan in brush border and basal membranes. This asymmetry may explain net transplacental transfer of this amino acid.
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Affiliation(s)
- Y Kudo
- Department of Human Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK.
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27
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Abstract
The human placenta secretes large amounts of corticotropin-releasing hormone (CRH) which was thought to exert a paracrine action in the placenta. We have recently characterized high-affinity binding sites for CRH in the human placenta. However, our studies utilized whole placental membranes, which did not identify the site of binding of CRH in the plasma membrane. In this study we investigated the characteristics of CRH binding to purified mother-facing, brush border membranes (BBM) and fetus-facing, basal plasma membranes (BPM) of the syncytiotrophoblast. The two membranes were separated by a series of differential and density-gradient centrifugations. The purity of the membranes was determined by measuring alkaline phosphatase, as a marker of BBM and Na+/K+ATPase as a marker of BPM. Each membrane showed specific and high-affinity binding. Scatchard analysis revealed a high-affinity binding site for CRH with Kd of 1.0 +/- 0.15 and 1.3 +/- 0.176 for BBM and BPM, respectively. The maximal number of binding sites was significantly different (P < 0.01) in the two plasma membranes: Bmax of 79 +/- 6.4 fmol/mg protein for BBM and 23 +/- 3.9 fmol/mg protein for BPM. Both the mother-facing and fetus-facing membranes of the syncytiotrophoblast contain binding proteins for CRH, with significantly more binding sites on the mother-facing membranes. The functional consequences of CRH binding could be different for the two polar membranes due to differential localization of second messenger systems between the two membrane types. It is proposed that partial purification of BBM and BPM provides a better system to study CRH action in the placenta, than whole placental membrane preparations.
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Affiliation(s)
- B Saeed
- The Medical School, University of Newcastle-upon-Tyne, UK.
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Ushigome F, Takanaga H, Matsuo H, Yanai S, Tsukimori K, Nakano H, Uchiumi T, Nakamura T, Kuwano M, Ohtani H, Sawada Y. Human placental transport of vinblastine, vincristine, digoxin and progesterone: contribution of P-glycoprotein. Eur J Pharmacol 2000; 408:1-10. [PMID: 11070177 DOI: 10.1016/s0014-2999(00)00743-3] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
To elucidate the role of P-glycoprotein in human placenta, we examined its expression in placenta, and the transcellular transport and uptake of P-glycoprotein substrates in cultured human placental choriocarcinoma epithelial cells (BeWo cells). The uptake of [(3)H]vinblastine and [(3)H]vincristine into BeWo cells was increased in the presence of a metabolic inhibitor, sodium azide. The basolateral-to-apical transcellular transport of [(3)H]vinblastine, [(3)H]vincristine and [(3)H]digoxin was greater than the apical-to-basolateral transcellular transport. In the presence of cyclosporin A, the basolateral-to-apical transcellular transport of [(3)H]vinblastine, [(3)H]vincristine and [(3)H]digoxin was significantly increased, and the apical-to-basolateral transcellular transport was decreased. The uptake of [(3)H]vinblastine, [(3)H]vincristine and [(3)H]digoxin into BeWo cells was significantly enhanced in the presence of several inhibitors, such as verapamil or mouse monoclonal antibody anti-P-glycoprotein MX-MDR (MRK16) as well as cyclosporin A. Although progesterone significantly enhanced the uptake of [(3)H]vinblastine, [(3)H]vincristine and [(3)H]digoxin into BeWo cells, the uptake of [(3)H]progesterone was not affected by these inhibitors. Immunoblot analysis revealed that P-glycoprotein with a molecular weight of 172 kDa was expressed in BeWo cells and isolated trophoblast cells. Furthermore, P-glycoprotein was detected in human placental brush-border membrane vesicles, but not in human placental basolateral membrane vesicles. In conclusion, these data suggest that P-glycoprotein is expressed on the brush-border membrane (maternal side) of human placental trophoblast cells. P-Glycoprotein is considered to regulate the transfer of several substances including vinblastine, vincristine and digoxin from mother to fetus, and to protect the fetus from toxic substances.
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Affiliation(s)
- F Ushigome
- Department of Medico-Pharmaceutical Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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29
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St-Pierre MV, Serrano MA, Macias RI, Dubs U, Hoechli M, Lauper U, Meier PJ, Marin JJ. Expression of members of the multidrug resistance protein family in human term placenta. Am J Physiol Regul Integr Comp Physiol 2000; 279:R1495-503. [PMID: 11004020 DOI: 10.1152/ajpregu.2000.279.4.r1495] [Citation(s) in RCA: 228] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The placenta serves, in part, as a barrier to exclude noxious substances from the fetus. In humans, a single-layered syncytium of polarized trophoblast cells and the fetal capillary endothelium separate the maternal and fetal circulations. P-glycoprotein is present in the syncytiotrophoblast throughout gestation, consistent with a protective role that limits exposure of the fetus to hydrophobic and cationic xenobiotics. We have examined whether members of the multidrug resistance protein (MRP) family are expressed in term placenta. After screening a placenta cDNA library, partial clones of MRP1, MRP2, and MRP3 were identified. Immunofluorescence and immunoblotting studies demonstrated that MRP2 was localized to the apical syncytiotrophoblast membrane. MRP1 and MRP3 were predominantly expressed in blood vessel endothelia with some evidence for expression in the apical syncytiotrophoblast. ATP-dependent transport of the anionic substrates dinitrophenyl-glutathione and estradiol-17-beta-glucuronide was also demonstrated in apical syncytiotrophoblast membranes. Given the cellular distribution of these transporters, we hypothesize that MRP isoforms serve to protect fetal blood from entry of organic anions and to promote the excretion of glutathione/glucuronide metabolites in the maternal circulation.
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Affiliation(s)
- M V St-Pierre
- Department of Internal Medicine, University Hospital, CH-8091 Zürich, Switzerland.
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30
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Johansson M, Jansson T, Powell TL. Na(+)-K(+)-ATPase is distributed to microvillous and basal membrane of the syncytiotrophoblast in human placenta. Am J Physiol Regul Integr Comp Physiol 2000; 279:R287-94. [PMID: 10896893 DOI: 10.1152/ajpregu.2000.279.1.r287] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Despite its importance for placental function, syncytiotrophoblast Na(+)-K(+)-ATPase has not been studied in detail. We purified syncytiotrophoblast microvillous (MVM) and basal (BM) membranes from full-term human placenta. Western blotting with isoform-specific antibodies demonstrated the presence of the alpha(1)-subunit, but not the alpha(2)- or alpha(3)-subunits, in MVM and BM. Relative density per unit membrane protein in BM was 48 +/- 1% (mean +/- SE, n = 4, P < 0.02) of that in the MVM. The activity of Na(+)-K(+)-ATPase was lower in BM (1.4 +/- 0.14 micromol. mg(-1). min(-1), n = 8, P < 0.02) than in MVM (3.9 +/- 0.25 micromol. mg(-1). min(-1)). Immunocytochemistry confirmed the distribution of Na(+)-K(+)-ATPase to MVM and BM. These findings suggest that the syncytiotrophoblast represents a type of transporting epithelium different from the classical epithelia found in the small intestine and kidney, where Na(+)-K(+)-ATPase is confined to the basolateral membrane only. This unique polarization of the Na(+) pump does not, however, preclude a net transcellular transport of Na(+) to the fetus.
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Affiliation(s)
- M Johansson
- Perinatal Center, Department of Physiology and Pharmacology, Göteborg University, S-405 30 Göteborg, Sweden.
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31
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Ayuk PT, Sibley CP, Donnai P, D'Souza S, Glazier JD. Development and polarization of cationic amino acid transporters and regulators in the human placenta. Am J Physiol Cell Physiol 2000; 278:C1162-71. [PMID: 10837344 DOI: 10.1152/ajpcell.2000.278.6.c1162] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have investigated L-arginine transport systems in the human placental syncytiotrophoblast across gestation using purified microvillous (MVM) and basal (BM) plasma membrane vesicles. In MVM from first-trimester and term placentas, L-arginine transport was by systems y(+) and y(+)L. In BM (term placentas), however, there was evidence for system y(+)L only. The Michaelis constant of system y(+)L was significantly lower (P < 0.05) in first-trimester compared with term MVM and lower in term MVM compared with BM (P < 0.05). There was no functional evidence for system b(0+) in term MVM or BM. Cationic amino acid transporter (CAT) 1, CAT 4, and 4F2hc were detected using RT-PCR in placentas throughout gestation. rBAT was not detected in term placentas. An approximately 85-kDa and an approximately 135-kDa protein was detected by Western blotting in MVM under reducing and nonreducing conditions, respectively, consistent with the 4F2hc monomer and the 4F2hc-light chain dimer, and their expression was significantly higher (P < 0.05) in term compared with first-trimester MVM. These proteins were not detected in BM despite functional evidence for system y(+)L. These data suggest different roles for 4F2hc in the development and polarization of cationic amino acid transporters in the syncytiotrophoblast.
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Affiliation(s)
- P T Ayuk
- Academic Unit of Child Health, University of Manchester and Department of Obstetrics and Gynecology, St. Mary's Hospital, Manchester M13 0JH, United Kingdom
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Kudo Y, Boyd CA. Human placental indoleamine 2,3-dioxygenase: cellular localization and characterization of an enzyme preventing fetal rejection. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1500:119-24. [PMID: 10564724 DOI: 10.1016/s0925-4439(99)00096-4] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In order to test the hypothesis (Munn, Zhou, Attwood, Bondarev, Conway, Marshall, Brown, Mellor, Science 281 (1998) 1191-1193) that localized placental tryptophan catabolism prevents immune rejection of the mammalian fetus, the cellular localization and characteristics of human placental indoleamine 2,3-dioxygenase (EC 1.13.11.42) were studied. The localization of indoleamine 2, 3-dioxygenase activity was determined quantitatively using cell fractionation by differential and discontinuous sucrose gradient centrifugation. Enzyme activity was looked for in isolated brush border microvillous plasma membranes of placental syncytiotrophoblast. We found that this membrane preparation (which showed a 32.4-fold purification from the starting homogenate with reference to the activity of a membrane marker enzyme, alkaline phosphatase (EC 3.1.3.1)) was strongly negatively enriched with indoleamine 2,3-dioxygenase (which showed a one twenty-fifth decrease in its specific activity). Placental indoleamine 2, 3-dioxygenase is thus not expressed in the maternal facing brush border membrane of syncytiotrophoblast. 1-Methyl-DL-tryptophan which was used by Munn et al. as a key experimental tool for inhibiting indoleamine 2,3-dioxygenase in the murine model showed a competitive inhibition of human placental indoleamine 2,3-dioxygenase with L-tryptophan. The hypothesis, based on experiments performed in mouse, may therefore be applicable to avoidance of immune rejection of the fetus in human pregnancy.
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Affiliation(s)
- Y Kudo
- Department of Human Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, UK.
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Fang J, Furesz TC, Smith CH, Fant ME. IGF binding protein-1 (IGFBP-1) is preferentially associated with the fetal-facing basal surface of the syncytiotrophoblast in the human placenta. Growth Horm IGF Res 1999; 9:438-444. [PMID: 10629164 DOI: 10.1054/ghir.1999.0127] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
IGF receptors are expressed in a spatially polarized manner on the syncytiotrophoblast cell membrane. We therefore examined the hypothesis that IGFBPs expressed at the maternal-fetal interface interact with distinct surfaces of the syncytiotrophoblast membrane to modulate IGF function. Membrane vesicles were prepared specifically from the maternal-facing, microvillous membrane (MVM) and the fetal-facing, basal membrane (BM) surfaces of the syncytiotrophoblast. The association of IGFBPs with each membrane preparation was determined by ligand blot analysis. A doublet migrating at 38/42 kD was detected in both MVM and BM preparations. Selective immunoprecipitation followed by ligand blot analysis identified this IGF binding species as IGFBP-3. Additionally, a protein migrating at approximately 29 kD was associated primarily with the BM. This protein was identified as IGFBP-1 by both immunoprecipitation and ligandblotting techniques. Non-denaturing PAGE revealed five distinct bands corresponding to different degrees of phosphorylation. The phosphorylation pattern of BM-associated IGFBP-1 was identical to that of native IGFBP-1 in amniotic fluid. Immunohistological analysis of term placenta revealed IGFBP-1-specific staining of the syncytiotrophoblast and the fetal capillary/pericapillary bed. The localization of IGFBP-1 to a distinct compartment within the fetal placenta, not in proximity to the syncytiotrophoblast type I IGF receptor, suggests it may play a role in regulating/targeting IGF activity within the stromal compartment or by exerting IGF-independent effects on the basal surface of the syncytiotrophoblast. The nature of its binding to the BM has not been determined.
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Affiliation(s)
- J Fang
- Department of Pediatrics, University of Texas-Houston Health Science Center, Houston, Texas 77030, USA
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Kenney SP, Kekuda R, Prasad PD, Leibach FH, Devoe LD, Ganapathy V. Cannabinoid receptors and their role in the regulation of the serotonin transporter in human placenta. Am J Obstet Gynecol 1999; 181:491-7. [PMID: 10454705 DOI: 10.1016/s0002-9378(99)70583-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE We sought to investigate the expression of cannabinoid receptors in human placenta and BeWo choriocarcinoma cells and study their role in the regulation of the serotonin transporter. STUDY DESIGN Expression of the 2 types of cannabinoid receptors (CB1 and CB2) in human placenta and BeWo cells was investigated by reverse transcriptase-polymerase chain reaction and Northern blot analysis. The involvement of the receptors in the regulation of the serotonin transporter expression was studied by using a cannabinoid receptor agonist (WIN 55212-2). BeWo cells were treated with the agonist in the presence or absence of forskolin, and the serotonin transporter activity was measured by assessing paroxetine-sensitive serotonin transport. Serotonin transporter density in cell membranes was monitored by measuring paroxetine-sensitive binding of RTI-55, a specific high-affinity ligand for the transporter. Agonist-induced changes in intracellular levels of cyclic adenosine monophosphate were also monitored. RESULTS Reverse transcriptase-polymerase chain reaction and Northern blot analysis demonstrated unequivocally that human placenta and BeWo cells express both types of cannabinoid receptors. Treatment of BeWo cells with the receptor agonist blocked the activity of the constitutive, as well as the forskolin-induced, serotonin transporter without affecting the serotonin transporter density. This effect is not mediated by alterations in intracellular cyclic adenosine monophosphate levels. CONCLUSION The results show that cannabinoid receptors are expressed in human placenta and BeWo cells and play a role in the regulation of the serotonin transporter activity. Human placenta is therefore a direct target for cannabinoids, and marijuana use during pregnancy is likely to affect the placental clearance of serotonin through the serotonin transporter.
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Affiliation(s)
- S P Kenney
- Department of Obstetrics and Gynecology, Medical College of Georgia, Augusta, USA
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35
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Ward S, Sibley C, Boyd R. Maternofetal and transplacental electrical potential differences. Placenta 1999. [DOI: 10.1016/s0143-4004(99)80026-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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36
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Ganapathy V, Prasad PD, Leibach FH. Use of human placenta in studies of monoamine transporters. Methods Enzymol 1998; 296:278-90. [PMID: 9779455 DOI: 10.1016/s0076-6879(98)96021-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Affiliation(s)
- V Ganapathy
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta 30912, USA
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37
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Sen A, Ghosh PK, Mukherjea M. Changes in lipid composition and fluidity of human placental basal membrane and modulation of bilayer protein functions with progress of gestation. Mol Cell Biochem 1998; 187:183-90. [PMID: 9788756 DOI: 10.1023/a:1006839711587] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Human placental syncytiotrophoblast basal membrane plays an important role in transfer of nutrients from the mother to the growing fetus all throughout gestation. The membrane lipid composition together with the bilayer fluidity is found to be the major index in modulation of these transport processes. In the present study, the effects of changing lipid composition on the placental basal membrane fluidity and the modulating influence of the latter on membrane enzyme and transport functions with progress of gestation,were investigated. Steady-state fluorescence analysis using 1,6-diphenyl- 1,3,5 hexatriene as the probe, indicated a decrease in fluorescence anisotropy of both labeled native membrane vesicles and liposomes prepared from lipids extracted from the basal membrane vesicles, signifying increased bilayer fluidity with progress of gestation. This in turn, was successfully correlated to the lowering of cholesterol content and enhanced phospholipid concentration with a steady decrease in cholesterol/phospholipid ratio during placental development. Enhanced Na+-K+-ATPase activity and steady-state glucose uptake across basal membrane with gestational progress suggested modulation of membrane protein functions by the fluidity, which was further corroborated by the increased bilayer fluidity and enzyme activity in benzyl alcohol treated basal membrane in each gestational age group.
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Affiliation(s)
- A Sen
- Department of Biochemistry, University College of Science, Calcutta, India
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38
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Verrijt CE, Kroos MJ, Huijskes-Heins MI, van Eijk HG, van Dijk JP. Non-transferrin iron uptake by trophoblast cells in culture. Significance of a NADH-dependent ferrireductase. Placenta 1998; 19:525-30. [PMID: 9778126 DOI: 10.1016/s0143-4004(98)91046-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study shows that trophoblast cells in culture are able to take up 59Fe from both Fe(III)nitrilotriacetate (NTA) and Fe-ascorbate. Fe in the presence of ascorbate is assumed to be Fe(III) in equilibrium with Fe(II). Kinetic parameters for non-transferrin iron uptake are determined from initial rate experiments, yielding Vmax=366 pmol/mg protein/5 min and Km=0.96 microM for Fe(III)NTA and Vmax=4043 pmol/mg protein/5 min and Km= 1.3 microM for Fe-ascorbate. Since trophoblast cells in culture reduce extracellular Fe(III)CN, and uptake of 59Fe from Fe-ascorbate is higher than that from Fe(III)NTA, it is suggested that reduction of Fe(III) precedes uptake. Uptake of 59Fe from both Fe-ascorbate and Fe(III)NTA is inhibited by Fe(II)chelator ferrozine and membrane-impermeable Fe(III)CN, further supporting this hypothesis. Studies with microvillous membrane vesicles (MMV) and basal membrane vesicles (BMV) reveal the presence of a NADH-dependent ferrireductase. Reduction of Fe(III)CN follows Michaelis-Menten kinetics, both with respect to [NADH] and [Fe]. NADPH is ineffective as electron donor. The rate of Fe(III)CN reduction by BMV is 2.5 times higher compared to MMV, while Km values for Fe(III)CN and NADH are not significantly different. These results reveal that a transmembrane NADH-dependent ferrireductase plays a role in uptake of non-transferrin iron. The possibility that this enzyme system is involved in iron transfer across the basal membrane is discussed.
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Affiliation(s)
- C E Verrijt
- Department of Chemical Pathology, Erasmus University Rotterdam, The Netherlands
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40
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Serrano MA, Brites D, Larena MG, Monte MJ, Bravo MP, Oliveira N, Marin JJ. Beneficial effect of ursodeoxycholic acid on alterations induced by cholestasis of pregnancy in bile acid transport across the human placenta. J Hepatol 1998; 28:829-39. [PMID: 9625319 DOI: 10.1016/s0168-8278(98)80234-1] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND/AIMS The existence of impairment in bile acid transport across the placenta during intrahepatic cholestasis of pregnancy and the effect of ursodeoxycholic acid treatment (1 g/day) were investigated. METHODS Kinetic parameters were calculated from experiments carried out on membrane vesicles obtained from basal (TPMb, fetal-facing) and apical (TPMa, maternal-facing) trophoblast plasma membranes. Bile acid uptake was measured using varying concentrations of [14C]-glycocholate and a rapid filtration technique. RESULTS The maximal velocity of transport (Vmax), the apparent affinity constant (Kt) and the efficiency (Ef) of transport (Vmax/Kt) of the anion:bile acid exchanger located at the TPMb were reduced in intrahepatic cholestasis of pregnancy. Ursodeoxycholic acid induced a reversal of Vmax, Kt and Ef to normal values. Owing to the 3-fold increase in Vmax, with no change in Kt, intrahepatic cholestasis of pregnancy induced an enhancement in Ef of ATP-independent bile acid transport across TPMa. Both Vmax and Ef were restored to normal values by ursodeoxycholic acid. Finally, in ATP-dependent bile acid transport across TPMa, a reduction in the Ef due to an increase in Vmax together with a more pronounced increase in Kt was found. This impairment was also reversed by ursodeoxycholic acid. CONCLUSIONS These results suggest that placenta bile acid transport systems are impaired in intrahepatic cholestasis of pregnancy. Moreover, together with the confirmed beneficial effect for intrahepatic cholestasis of pregnancy patients, such as the relief of pruritus and the improvement in biochemical markers of cholestasis, ursodeoxycholic acid treatment restores the ability of the placenta to carry out vectorial bile acid transfer.
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Affiliation(s)
- M A Serrano
- Department of Biochemistry and Molecular Biology, University of Salamanca, Spain
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Novak DA, Matthews JC, Beveridge MJ, Yao SY, Young J, Kilberg MS. Demonstration of system y+L activity on the basal plasma membrane surface of rat placenta and developmentally regulated expression of 4F2HC mRNA. Placenta 1997; 18:643-8. [PMID: 9364599 DOI: 10.1016/s0143-4004(97)90005-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Na(+)-independent cationic amino acid transport in the rat placenta occurs by leucine-sensitive and leucine-insensitive pathways. The ontogeny of these transport mechanisms within the rat placenta has been described recently. To assign the leucine-inhibitable portion of uptake definitively the uptake of [3H]arginine was studied in the presence of both BCH (to inhibit system Bo,+) and varied concentrations of leucine. Uptake of arginine into basal-enriched membrane vesicles derived from rat placenta was, in the presence of sodium, inhibited by micromolar concentrations of leucine, consistent with assignment of this activity to system y+L. In contrast, the majority of arginine uptake into apical-enriched membrane vesicles was leucine insensitive. Messenger RNA derived from rat placenta at days 14, 16, 18 and 20 of gestation was hybridized with full-length rat cDNA probes against NBAT and 4F2HC (thought to encode proteins associated with system bo,+ and y+L activities, respectively). No NBAT mRNA was detected, whereas 4F2HC mRNA was present at all gestational stages, increasing 12-fold over the last third of gestation. It is concluded that system y+L is present in the basal plasma membrane of the rat placenta syncytium and is subject to developmental regulation by a mechanism that alters the steady content of 4F2HC mRNA.
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Affiliation(s)
- D A Novak
- Department of Pediatrics, University of Florida College of Medicine, USA
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Abstract
The recent demonstration of multiple high-affinity leucine-sensitive cationic transport systems prompted this investigation of their role in lysine uptake in basal cell membrane. Transport of lysine by basal membrane was saturable at both 22 and 37 degrees C and linear in time to 1 min and 30 sec, respectively. At 22 degrees C, at least two systems were active. The portion of uptake inhibited by the sulphydryl binding reagent N-ethylmaleimide (NEM) but not by leucine in the absence of sodium had a high K(m) and high Vmax and was attributed to system y+. NEM-insensitive uptake was fitted by a one-system model with K(m) (+/- s.e.) of 4 +/- 1 microM and a Vmax of 0.9 +/- 0.1 pmol/mg protein/min. This component was completely inhibited by leucine in the absence of sodium but not by glutamine in the presence of sodium. Therefore, it was attributed to system bo,+. At 37 degrees C, at least three systems were active. For essentially the same reasons as above the NEM inhibitable uptake was attributed to system y+. NEM-insensitive uptake was fitted by a one-system model with K(m) of 26 +/- 7 microM and Vmax of 11.1 +/- 2.8 pmol/mg protein/30 sec. Inhibition studies, however, indicated its heterogeneity. NEM-insensitive saturable uptake was only partially inhibited by either leucine in the absence of sodium (system bo,+) or by glutamine in the presence of sodium (system y+L). It is concluded that the NEM-insensitive portion of lysine uptake at 37 degrees C represents activity of both system bo,+ and the temperature-sensitive system y+L. As a previous investigation indicates, only one of these (system y+L) is present in the more specialized microvillous membrane. The demonstration of functional differences in the high affinity leucine transporters of basal and microvillous membrane in this and our previous investigations suggest that the two membranes possess different transport or modifier proteins.
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Affiliation(s)
- T C Furesz
- Edward Mallinckrodt Department of Pediatrics, St Louis Children's Hospital, Washington University School of Medicine, Missouri 63110, USA
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Birdsey TJ, Boyd RD, Sibley CP, Greenwood SL. Microvillous membrane potential (Em) in villi from first trimester human placenta: comparison to Em at term. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 273:R1519-28. [PMID: 9362319 DOI: 10.1152/ajpregu.1997.273.4.r1519] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The microvillous membrane (MVM) potential (Em) of first trimester human placental villi was measured and compared with that in villi from term human placentas. The median Em in first trimester villi (-28 mV) was significantly more negative than that at term (-21 mV; P < 0.001). The median Em measured in villi from early (weeks 6-11) first trimester (-32 mV) was significantly more negative than that in late (weeks 12 and 13) first trimester villi (-24 mV; P < 0.001). Elevating extracellular KCl concentration induced a significant depolarization of Em in both first trimester and term villi (P < 0.05 and P < 0.001, respectively). The magnitude of this depolarization was greater in first trimester than at term, indicating that the ion conductance of the MVM changes with gestation. Exposure to ouabain induced a significant depolarization of Em (3 mV: P < 0.05) in first trimester villi but had little effect at term. These results suggest that microvillous membrane electrophysiology changes with placental development. An alteration in the relative K+:Cl- conductance of the MVM is likely to be a major contributor to the change in the magnitude of Em.
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Affiliation(s)
- T J Birdsey
- Department of Child Health and School of Biological Sciences, University of Manchester, St. Mary's Hospital, United Kingdom
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Abstract
Glutamine plays an important role in fetal nutrition. This study explored the transport of [3H]glutamine into apical and basal predominant membrane vesicles derived from rat and human placenta. Na+-dependent glutamine transport was present in both apical and basal predominant vesicles derived from 20- and, to a lesser degree, 14-day gestation rat placenta. Amino-acid transport systems A, ASC-like, B(o,+) (in apical membrane vesicles) and, perhaps, y+L were involved in Na+-dependent glutamine transport. Na+-dependent glutamine uptake into human placental microvillus and basolateral membrane vesicles also occurred via several distinct transport activities. Glutamine transport via system N was not detected in either rat or human placental preparations. Na+-dependent glutamine transport in the rat was more pronounced in basal as compared to apical membrane vesicles. Conversely, in the human preparations, activity was significantly higher in microvillus as compared to basolateral membrane vesicles. It is concluded that Na+-dependent glutamine transport occurs through a variety of transport agencies in both the rat and human placenta. Transport varies with ontogeny and between species.
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Affiliation(s)
- D A Novak
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, USA
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45
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Pavía J, Muñoz M, Jiménez E, Martos F, Gonzalez-Correa JA, De la Cruz JP, Garcia V, Sanchez de la Cuesta F. Pharmacological characterization and distribution of muscarinic receptors in human placental syncytiotrophoblast brush-border and basal plasma membranes. Eur J Pharmacol 1997; 320:209-14. [PMID: 9059856 DOI: 10.1016/s0014-2999(96)00889-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Based on the existence of choline acetyltransferase and acetylcholine in human placenta, we have investigated the presence of muscarinic acetylcholine receptors in brush-border and basal plasma membranes from human term placenta. Radioligand binding assay, using [3H]N-methyl-scopolamine as tracer, showed the existence of acetylcholine muscarinic receptors in brush-border (Kd 0.28 +/- 0.04 nM; Bmax 9.4 +/- 1.6 fmol/mg protein) and basal plasma membranes (Kd 0.24 +/- 0.05 nM; Bmax 34.3 +/- 6.3 fmol/mg protein). In order to perform a pharmacological characterization of these receptors, competition binding experiments were carried out using the muscarinic receptor antagonists pirenzepine, (11(2-diethyl-amino)methyl)-1-piperidinylacetyl-5-11-dihydro-6H-py rido(14) benzodiazepine (AF-DX 116), himbacine, 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP), dicyclomine and hexahydro-sila-difenidol (HHSD). The results obtained showed that the muscarinic receptors in brush-border and basal plasma membranes belong to different subtypes. In brush-border membranes, the receptor found match in terms of affinity for the antagonists with the muscarinic M1 receptor subtype (Ki pirenzepine, 13.6 +/- 8.2 nM; Ki AF-DX 116, 1680 +/- 271 nM; Ki himbacine, 212 +/- 6.5 nM; Ki 4-DAMP. 1.5 +/- 0.4 nM; Ki dicyclomine, 5.1 +/- 0.8 nM; Ki HHSD, 34.3 +/- 7.3 nM), whereas the receptor in basal plasma membrane seems to be of the muscarinic M2 receptor subtype (Ki pirenzepine, 202 +/- 48 nM; Ki AF-DX 116, 124 +/- 60 nM; Ki himbacine, 20.6 +/- 4.8 nM; Ki 4-DAMP, 4.5 +/- 1.2 nM; Ki dicyclomine, 54.6 +/- 22 nM; Ki HHSD, 89.2 +/- 15.8 nM). The results obtained show the existence of muscarinic acetylcholine receptors in brush-border and basal plasma membranes from human term placenta with a different distribution pattern in terms of number of receptors and distribution of different subtypes. The functional significance of these findings is as yet unknown, but these receptors probably mediate different functions as they belong to different subtypes and are coupled to different second messengers.
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Affiliation(s)
- J Pavía
- Department of Pharmacology, Malaga School of Medicine, Malaga University, Spain.
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46
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Fang J, Furesz TC, Lurent RS, Smith CH, Fant ME. Spatial polarization of insulin-like growth factor receptors on the human syncytiotrophoblast. Pediatr Res 1997; 41:258-65. [PMID: 9029648 DOI: 10.1203/00006450-199702000-00017] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The expression of IGF receptors on the maternal-facing, microvillous membrane (MVM) surface and the fetal-facing, basal membrane (BM) surface of the syncytiotrophoblast was studied using standard ligand binding assays, covalent cross-linking techniques, and immunoblot analysis. Scatchard analysis of [125I]IGF-I and -II binding revealed the presence of both high and low affinity binding sites associated with each membrane preparation that did not clearly distinguish between the two membrane preparations. Cross-linking analysis, however, demonstrated type I and type II IGF receptors associated primarily with MVM, suggesting that nonreceptor binding sites may contribute to total membrane binding. Ligand blot analysis revealed that BM are uniquely associated with 29- and 24-kD IGF binding proteins (IGFBPs). [125I]QAYL-IGF-I, having reduced affinity for IGFBPs, was therefore used to study receptor-specific binding. Approximately 5-fold more type I IGF receptors were shown to be associated with MVM than BM by Scatchard and cross-linking analyses. This was confirmed by immunoblot analysis. By contrast, immunoblot analysis revealed approximately 50-100% more type II IGF receptor protein associated with BM, whereas cross-linking to [125I]IGF-II revealed a MVM predominance. In the presence of 5 mM mannose 6-phosphate, however, a substantial increase in [125I]IGF-II cross-linked to the type II IGF receptor was observed in BM but not MVM consistent with immunoblot analysis. These data demonstrate that type 1 and unoccupied type II IGF receptors are expressed primarily on the maternal-facing. MVM surface of the syncytiotrophoblast.
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Affiliation(s)
- J Fang
- Edward G. Mallinkrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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47
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Kudo Y, Boyd C. Mechanisms of transepithelial transport of amino acids in human placental syncytiotrophoblast. Placenta 1997. [DOI: 10.1016/s0143-4004(05)80163-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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48
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Verrijt CE, Kroos MJ, van Noort WL, van Eijk HG, van Dijk JP. Binding of human isotransferrin variants to microvillous and basal membrane vesicles from human term placenta. Placenta 1997; 18:71-7. [PMID: 9032812 DOI: 10.1016/s0143-4004(97)90073-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Transferrin (Tf)-dependent iron transfer from mother to fetus is mediated by Tf receptors (TfRs) which are present on both microvillous and basal membranes of human placental syncytiotrophoblast. We used microvillous and basal membrane vesicles, both isolated from the same human term placenta, to investigate the binding of [125I]-labelled diferric bi-bi antennary tetra-sialo Tf (bb Tf), bi-tri-antennary penta-sialo Tf (bt Tf) and tri-tri-antennary hexa-sialo Tf (tt Tf). To diminish the effect of endogenous Tf, membrane vesicles were washed before binding of [125I]-Tf. The number of TfRs on microvillous membranes was 6.1 +/- 2.4 (mean +/- s.d., n = 15) times higher than that on basal membranes, whereas the affinity of TfRs on basal membranes was 3.9 +/- 0.4 (mean +/- s.d., n = 15) times higher than that of TfRs on microvillous membranes, irrespective the isoTf used. The affinity constants of TfRs on both microvillous and basal membranes were higher for bb Tf than for bt Tf and higher for bt Tf than for tt Tf. However, these latter differences were rather small and probably not of physiological importance.
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Affiliation(s)
- C E Verrijt
- Department of Chemical Pathology, Erasmus University Rotterdam, The Netherlands
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Jiménez E, Muñoz M, Pavia J, Montiel M. Angiotensin II receptor in human placental syncytiotrophoblast plasma membranes. Life Sci 1996; 58:877-82. [PMID: 8786693 DOI: 10.1016/0024-3205(96)00030-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Previous studies have reported the presence of high-affinity angiotensin II (Ang II) binding sites in human placental tissue, but it has not been determined whether these are located in brush border (BBM) or basolateral plasma (BPM) membranes of the syncytiotrophoblast. Our findings provide no evidence for Ang II receptors in BBM, yet they reveal a single class of binding sites in BPM preparations (Kd of 4.08+/-0.61 nM and B(max) of 2368.7+/-658.2 fmol/mg protein). Pharmacological characterization also revealed that this receptor was an AT1 receptor subtype. Moreover, isoelectric focusing analysis demonstrated a predominant Ang II-receptor complex migrating to pl 7.0, and two minor receptors at pl 7.2 and 6.5. These data suggest a physiological role of the renin-angiotensin system on syncytiotrophoblast BPM in regulating placental function.
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Affiliation(s)
- E Jiménez
- Department of Biochemistry and Molecular Biology, University of Malaga, Spain
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50
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Itakura A, Kurauchi O, Mizutani S, Tomoda Y. Trophoblast cell monolayers on polycarbonate membranes as a preparative approach for studies of transcellular transport. J Perinat Med 1996; 24:651-6. [PMID: 9120748 DOI: 10.1515/jpme.1996.24.6.651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To investigate mechanisms of transplacental transfer, the trophoblast-derived cells were cultured on a polycarbonate membrane with 0.4 micron pores and medium on each side. The cells could form microscopically continuous cellular sheets over Transwell polycarbonate membranes. Permeability studies suggested however that the cell layer possesses a significant leak that must be controlled for. The results indicate that the transfer of substances through lateral intercellular spaces must be considered when studies of trans-trophoblast transfer are performed using cell monolayers.
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Affiliation(s)
- A Itakura
- Department of Obstetrics and Gynecology, Nagoya University School of Medicine, Japan
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