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The LDL receptor: Traffic and function in trophoblast cells under normal and pathological conditions. Placenta 2022; 127:12-19. [DOI: 10.1016/j.placenta.2022.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 07/11/2022] [Accepted: 07/15/2022] [Indexed: 12/18/2022]
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Strahlhofer-Augsten M, Schliefsteiner C, Cvitic S, George M, Lang-Olip I, Hirschmugl B, Marsche G, Lang U, Novakovic B, Saffery R, Desoye G, Wadsack C. The Distinct Role of the HDL Receptor SR-BI in Cholesterol Homeostasis of Human Placental Arterial and Venous Endothelial Cells. Int J Mol Sci 2022; 23:ijms23105364. [PMID: 35628180 PMCID: PMC9141204 DOI: 10.3390/ijms23105364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/28/2022] [Accepted: 04/30/2022] [Indexed: 11/17/2022] Open
Abstract
As opposed to adults, high-density lipoprotein (HDL) is the main cholesterol carrying lipoprotein in fetal circulation. The major HDL receptor, scavenger receptor class B type I (SR-BI), contributes to local cholesterol homeostasis. Arterial endothelial cells (ECA) from human placenta are enriched with cholesterol compared to venous endothelial cells (ECV). Moreover, umbilical venous and arterial plasma cholesterol levels differ markedly. We tested the hypothesis that the uptake of HDL-cholesteryl esters differs between ECA and ECV because of the differential expression of SR-BI. We aimed to identify the key regulators underlying these differences and the functional consequences. Immunohistochemistry was used for visualization of SR-BI in situ. ECA and ECV were isolated from the chorionic plate of human placenta and used for RT-qPCR, Western Blot, and HDL uptake assays with 3H- and 125I-labeled HDL. DNA was extracted for the methylation profiling of the SR-BI promoter. SR-BI regulation was studied by exposing ECA and ECV to differential oxygen concentrations or shear stress. Our results show elevated SR-BI expression and protein abundance in ECA compared to ECV in situ and in vitro. Immunohistochemistry demonstrated that SR-BI is mainly expressed on the apical side of placental endothelial cells in situ, allowing interaction with mature HDL circulating in the fetal blood. This was functionally linked to a higher increase of selective cholesterol ester uptake from fetal HDL in ECA than in ECV, and resulted in increased cholesterol availability in ECA. SR-BI expression on ECV tended to decrease with shear stress, which, together with heterogeneous immunostaining, suggests that SR-BI expression is locally regulated in the placental vasculature. In addition, hypomethylation of several CpG sites within the SR-BI promoter region might contribute to differential expression of SR-BI between chorionic arteries and veins. Therefore, SR-BI contributes to a local cholesterol homeostasis in ECA and ECV of the human feto-placental vasculature.
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Affiliation(s)
- Manuela Strahlhofer-Augsten
- Research Unit, Department of Obstetrics and Gynecology, Medical University of Graz, 8036 Graz, Austria; (M.S.-A.); (C.S.); (S.C.); (B.H.); (G.D.)
- BioBank Graz, Medical University of Graz, 8036 Graz, Austria
| | - Carolin Schliefsteiner
- Research Unit, Department of Obstetrics and Gynecology, Medical University of Graz, 8036 Graz, Austria; (M.S.-A.); (C.S.); (S.C.); (B.H.); (G.D.)
| | - Silvija Cvitic
- Research Unit, Department of Obstetrics and Gynecology, Medical University of Graz, 8036 Graz, Austria; (M.S.-A.); (C.S.); (S.C.); (B.H.); (G.D.)
- Research Unit of Analytical Mass Spectrometry, Cell Biology and Biochemistry of Inborn Errors of Metabolism, Department of Paediatrics and Adolescent Medicine, Medical University of Graz, 8036 Graz, Austria
| | - Meekha George
- Otto Loewi Research Center, Division of Pathophysiology and Immunology, Medical University of Graz, 8010 Graz, Austria;
| | - Ingrid Lang-Olip
- Gottfried Schatz Research Center, Divison of Cell Biology, Histology and Embryology, Medical University of Graz, 8036 Graz, Austria;
| | - Birgit Hirschmugl
- Research Unit, Department of Obstetrics and Gynecology, Medical University of Graz, 8036 Graz, Austria; (M.S.-A.); (C.S.); (S.C.); (B.H.); (G.D.)
| | - Gunther Marsche
- Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, 8010 Graz, Austria;
| | - Uwe Lang
- Research Unit, Department of Obstetrics and Gynecology, Medical University of Graz, 8036 Graz, Austria; (M.S.-A.); (C.S.); (S.C.); (B.H.); (G.D.)
| | - Boris Novakovic
- Molecular Immunity, Infection and Immunity Theme, Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia; (B.N.); (R.S.)
| | - Richard Saffery
- Molecular Immunity, Infection and Immunity Theme, Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia; (B.N.); (R.S.)
| | - Gernot Desoye
- Research Unit, Department of Obstetrics and Gynecology, Medical University of Graz, 8036 Graz, Austria; (M.S.-A.); (C.S.); (S.C.); (B.H.); (G.D.)
| | - Christian Wadsack
- Research Unit, Department of Obstetrics and Gynecology, Medical University of Graz, 8036 Graz, Austria; (M.S.-A.); (C.S.); (S.C.); (B.H.); (G.D.)
- Correspondence:
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Nava-Salazar S, Flores-Pliego A, Pérez-Martínez G, Parra-Hernández S, Vanoye-Carlo A, Ibarguengoitia-Ochoa F, Perichart-Perera O, Reyes-Muñoz E, Solis-Paredes JM, Espino Y Sosa S, Estrada-Gutierrez G. Resistin Modulates Low-Density Lipoprotein Cholesterol Uptake in Human Placental Explants via PCSK9. Reprod Sci 2022; 29:3242-3253. [PMID: 35467263 DOI: 10.1007/s43032-022-00943-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 04/09/2022] [Indexed: 11/25/2022]
Abstract
Maternal metabolic status influences pregnancy and, consequently, the perinatal outcome. Resistin is a pro-inflammatory adipokine predominantly expressed and secreted by mononuclear cells, adipose tissue, and placental trophoblastic cells during pregnancy. Recently, we reported an inverse association between maternal resistin levels and fetal low-density lipoprotein cholesterol (LDL-C). Then, in this work, we used a human placental explant model and the trophoblast cell line JEG-3 to evaluate whether resistin affects placental LDL-C uptake. Resistin exposure induced the transcription factor SREBP-2, LDLR, and PCSK9 mRNA expression, and changes at the protein level were confirmed by immunohistochemistry and Western blot. However, for LDLR, the changes were not consistent between mRNA and protein levels. Using a labeled LDL-cholesterol (BODIPY FL LDL), uptake assay demonstrated that the LDL-C was significantly decreased in placental explants exposed to a high dose of resistin and a lesser extent in JEG-3 cells. In summary, resistin induces PCSK9 expression in placental explants and JEG-3 cells, which could be related to negative regulation of the LDLR by lysosomal degradation. These findings suggest that resistin may significantly regulate the LDL-C uptake and transport from the maternal circulation to the fetus, affecting its growth and lipid profile.
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Affiliation(s)
- Sonia Nava-Salazar
- Department of Immunobiochemistry, Instituto Nacional de Perinatologia, Mexico City, Mexico
| | - Arturo Flores-Pliego
- Department of Immunobiochemistry, Instituto Nacional de Perinatologia, Mexico City, Mexico
| | | | - Sandra Parra-Hernández
- Department of Immunobiochemistry, Instituto Nacional de Perinatologia, Mexico City, Mexico
| | | | | | - Otilia Perichart-Perera
- Department of Nutrition and Bioprogramming, Instituto Nacional de Perinatologia, Mexico City, Mexico
| | - Enrique Reyes-Muñoz
- Coordination of Gynecologic and Perinatal Endocrinology, Instituto Nacional de Perinatologia, Mexico City, Mexico
| | - Juan Mario Solis-Paredes
- Department of Human Genetics and Genomics, Instituto Nacional de Perinatologia, Mexico City, Mexico
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Human Placental Intracellular Cholesterol Transport: A Focus on Lysosomal and Mitochondrial Dysfunction and Oxidative Stress. Antioxidants (Basel) 2022; 11:antiox11030500. [PMID: 35326150 PMCID: PMC8944475 DOI: 10.3390/antiox11030500] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/24/2022] [Accepted: 03/01/2022] [Indexed: 11/18/2022] Open
Abstract
The placenta participates in cholesterol biosynthesis and metabolism and regulates exchange between the maternal and fetal compartments. The fetus has high cholesterol requirements, and it is taken up and synthesized at elevated rates during pregnancy. In placental cells, the major source of cholesterol is the internalization of lipoprotein particles from maternal circulation by mechanisms that are not fully understood. As in hepatocytes, syncytiotrophoblast uptake of lipoprotein cholesterol involves lipoprotein receptors such as low-density lipoprotein receptor (LDLR) and scavenger receptor class B type I (SR-BI). Efflux outside the cells requires proteins such as the ATP-binding cassette (ABC) transporters ABCA1 and ABCG1. However, mechanisms associated with intracellular traffic of cholesterol in syncytiotrophoblasts are mostly unknown. In hepatocytes, uptaken cholesterol is transported to acidic late endosomes (LE) and lysosomes (LY). Proteins such as Niemann–Pick type C 1 (NPC1), NPC2, and StAR related lipid transfer domain containing 3 (STARD3) are required for cholesterol exit from the LE/LY. These proteins transfer cholesterol from the lumen of the LE/LY into the LE/LY-limiting membrane and then export it to the endoplasmic reticulum, mitochondria, or plasma membrane. Although the production, metabolism, and transport of cholesterol in placental cells are well explored, there is little information on the role of proteins related to intracellular cholesterol traffic in placental cells during physiological or pathological pregnancies. Such studies would be relevant for understanding fetal and placental cholesterol management. Oxidative stress, induced by generating excess reactive oxygen species (ROS), plays a critical role in regulating various cellular and biological functions and has emerged as a critical common mechanism after lysosomal and mitochondrial dysfunction. This review discusses the role of cholesterol, lysosomal and mitochondrial dysfunction, and ROS in the development and progression of hypercholesterolemic pregnancies.
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Woollett LA, Catov JM, Jones HN. Roles of maternal HDL during pregnancy. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159106. [PMID: 34995789 DOI: 10.1016/j.bbalip.2021.159106] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/11/2021] [Accepted: 12/05/2021] [Indexed: 01/08/2023]
Abstract
BACKGROUND High density lipoproteins (HDL) were first linked to cardiovascular disease (CVD) over 30 years ago when an inverse relationship was shown between CVD and HDL-cholesterol levels. It is now apparent that HDL composition and function, not cholesterol levels, are the pertinent measurements describing HDL's role in various disease processes, especially those with subclinical or overt inflammation. SCOPE OF REVIEW Pregnancy is also an inflammatory state. When inflammation becomes excessive during pregnancy, there is an increased risk for adverse outcomes that affect the health of the mother and fetus, including preterm birth and preeclampsia. Though studies on HDL during pregnancy are limited, recent evidence demonstrates that HDL composition and function change during pregnancy and in women with adverse outcomes. GENERAL SIGNIFICANCE In this review, we will discuss how HDL may play a role in maintaining a healthy pregnancy and how impairments in function could lead to pregnancies with adverse outcomes.
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Affiliation(s)
- Laura A Woollett
- Department of Pathology and Laboratory Medicine, University of Cincinnati Medical School, Cincinnati, OH, United States of America.
| | - Janet M Catov
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh School of Medicine and Magee Women's Research Institute, Pittsburgh, PA, United States of America.
| | - Helen N Jones
- Center for Research in Perinatal Outcomes, Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, United States of America; Center for Research in Perinatal Outcomes, Department of Obstetrics and Gynecology, University of Florida, Gainesville, FL, United States of America.
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Pregnancy is accompanied by larger high density lipoprotein particles and compositionally distinct subspecies. J Lipid Res 2021; 62:100107. [PMID: 34416270 PMCID: PMC8441201 DOI: 10.1016/j.jlr.2021.100107] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 08/03/2021] [Accepted: 08/13/2021] [Indexed: 12/24/2022] Open
Abstract
Pregnancy is accompanied by significant physiological changes, which can impact the health and development of the fetus and mother. Pregnancy-induced changes in plasma lipoproteins are well documented, with modest to no impact observed on the generic measure of high density lipoprotein (HDL) cholesterol. However, the impact of pregnancy on the concentration and composition of HDL subspecies has not been examined in depth. In this prospective study, we collected plasma from 24 nonpregnant and 19 pregnant women in their second trimester. Using nuclear magnetic resonance (NMR), we quantified 11 different lipoprotein subspecies from plasma by size, including three in the HDL class. We observed an increase in the number of larger HDL particles in pregnant women, which were confirmed by tracking phospholipids across lipoproteins using high-resolution gel-filtration chromatography. Using liquid chromatography-mass spectrometry (LC-MS), we identified 87 lipid-associated proteins across size-speciated fractions. We report drastic shifts in multiple protein clusters across different HDL size fractions in pregnant females compared with nonpregnant controls that have major implications on HDL function. These findings significantly elevate our understanding of how changes in lipoprotein metabolism during pregnancy could impact the health of both the fetus and the mother.
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Stadler JT, Wadsack C, Marsche G. Fetal High-Density Lipoproteins: Current Knowledge on Particle Metabolism, Composition and Function in Health and Disease. Biomedicines 2021; 9:biomedicines9040349. [PMID: 33808220 PMCID: PMC8067099 DOI: 10.3390/biomedicines9040349] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 12/20/2022] Open
Abstract
Cholesterol and other lipids carried by lipoproteins play an indispensable role in fetal development. Recent evidence suggests that maternally derived high-density lipoprotein (HDL) differs from fetal HDL with respect to its proteome, size, and function. Compared to the HDL of adults, fetal HDL is the major carrier of cholesterol and has a unique composition that implies other physiological functions. Fetal HDL is enriched in apolipoprotein E, which binds with high affinity to the low-density lipoprotein receptor. Thus, it appears that a primary function of fetal HDL is the transport of cholesterol to tissues as is accomplished by low-density lipoproteins in adults. The fetal HDL-associated bioactive sphingolipid sphingosine-1-phosphate shows strong vasoprotective effects at the fetoplacental vasculature. Moreover, lipoprotein-associated phospholipase A2 carried by fetal-HDL exerts anti-oxidative and athero-protective functions on the fetoplacental endothelium. Notably, the mass and activity of HDL-associated paraoxonase 1 are about 5-fold lower in the fetus, accompanied by an attenuation of anti-oxidative activity of fetal HDL. Cholesteryl ester transfer protein activity is reduced in fetal circulation despite similar amounts of the enzyme in maternal and fetal serum. This review summarizes the current knowledge on fetal HDL as a potential vasoprotective lipoprotein during fetal development. We also provide an overview of whether and how the protective functionalities of HDL are impaired in pregnancy-related syndromes such as pre-eclampsia or gestational diabetes mellitus.
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Affiliation(s)
- Julia T. Stadler
- Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Universitätsplatz 4, 8010 Graz, Austria
- Correspondence: (J.T.S.); (G.M.); Tel.: +43-316-385-74115 (J.T.S.); +43-316-385-74128 (G.M.)
| | - Christian Wadsack
- Department of Obstetrics and Gynecology, Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria;
| | - Gunther Marsche
- Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Universitätsplatz 4, 8010 Graz, Austria
- Correspondence: (J.T.S.); (G.M.); Tel.: +43-316-385-74115 (J.T.S.); +43-316-385-74128 (G.M.)
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Materno-fetal cholesterol transport during pregnancy. Biochem Soc Trans 2021; 48:775-786. [PMID: 32369555 DOI: 10.1042/bst20190129] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 03/21/2020] [Accepted: 03/31/2020] [Indexed: 12/23/2022]
Abstract
Cholesterol is a major nutrient required for fetal growth. It is also a precursor for the synthesis of steroid hormones and essential for the development and maturation of fetal organs. During pregnancy, the placenta controls the transport of cholesterol from the mother to the fetus and vice versa. Cholesterol originating from the maternal circulation has to cross two main membrane barriers to reach the fetal circulation: Firstly, cholesterol is acquired by the apical side of the syncytiotrophoblast (STB) from the maternal circulation as high-density lipoprotein (HDL)-, low-density lipoprotein (LDL)- or very-low-density lipoprotein (VLDL)-cholesterol and secreted at the basal side facing the villous stroma. Secondly, from the villous stroma cholesterol is taken up by the endothelium of the fetal vasculature and transported to the fetal vessels. The proteins involved in the uptake of HDL-, LDL-, VLDL- or unesterified-cholesterol are scavenger receptor type B class 1 (SR-B1), cubulin, megalin, LDL receptor (LDLR) or Niemann-Pick-C1 (NPC1) which are localized at the apical and/or basal side of the STB or at the fetal endothelium. Through interaction with apolipoproteins (e.g. apoA1) cholesterol is effluxed either to the maternal or fetal circulation via the ATP-binding-cassette (ABC)-transporter A1 and ABCG1 localized at the apical/basal side of the STB or the endothelium. In this mini-review, we summarize the transport mechanisms of cholesterol across the human placenta, the expression and localization of proteins involved in the uptake and efflux of cholesterol, and the expression pattern of cholesterol transport proteins in pregnancy pathologies such as pre-eclampsia, gestational diabetes mellitus and intrauterine growth retardation.
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Mauri M, Calmarza P, Ibarretxe D. Dyslipemias and pregnancy, an update. CLINICA E INVESTIGACION EN ARTERIOSCLEROSIS 2020; 33:41-52. [PMID: 33309071 DOI: 10.1016/j.arteri.2020.10.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 09/25/2020] [Accepted: 10/05/2020] [Indexed: 12/12/2022]
Abstract
During pregnancy there is a physiological increase in total cholesterol (TC) and triglycerides (TG) plasma concentrations, due to increased insulin resistance, oestrogens, progesterone, and placental lactogen, although their reference values are not exactly known, TG levels can increase up to 300mg/dL, and TC can go as high as 350mg/dL. When the cholesterol concentration exceeds the 95th percentile (familial hypercholesterolaemia (FH) and transient maternal hypercholesterolaemia), there is a predisposition to oxidative stress in foetal vessels, exposing the newborn to a greater fatty streaks formation and a higher risk of atherosclerosis. However, the current treatment of pregnant women with hyperlipidaemia consists of a diet and suspension of lipid-lowering drugs. The most prevalent maternal hypertriglyceridaemia (HTG) is due to secondary causes, like diabetes, obesity, drugs, etc. The case of severe HTG due to genetic causes is less prevalent, and can be a higher risk of maternal-foetal complications, such as, acute pancreatitis (AP), pre-eclampsia, preterm labour, and gestational diabetes. Severe HTG-AP is a rare but potentially lethal pregnancy complication, for the mother and the foetus, usually occurs during the third trimester or in the immediate postpartum period, and there are no specific protocols for its diagnosis and treatment. In conclusion, it is crucial that dyslipidaemia during pregnancy must be carefully evaluated, not just because of the acute complications, but also because of the future cardiovascular morbidity and mortality of the newborn child. That is why the establishment of consensus protocols or guidelines is essential for its management.
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Affiliation(s)
- Marta Mauri
- Unidad de Lípidos, Servicio de Medicina Interna, Hospital de Terrassa, Consorci Sanitari de Terrassa, Terrassa, Barcelona, España
| | - Pilar Calmarza
- Servicio de Bioquímica Clínica, Hospital Universitario Miguel Servet, Universidad de Zaragoza, Zaragoza, España.
| | - Daiana Ibarretxe
- Unidad de Medicina Vascular y Metabolismo (UVASMET), Hospital Universitario de Reus, Universidad Rovira y Virgili, IISPV, CIBERDEM, Reus, Tarragona, España
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Okala SG, Sise EA, Sosseh F, Prentice AM, Woollett LA, Moore SE. Maternal plasma lipid levels across pregnancy and the risks of small-for-gestational age and low birth weight: a cohort study from rural Gambia. BMC Pregnancy Childbirth 2020; 20:153. [PMID: 32164563 PMCID: PMC7068879 DOI: 10.1186/s12884-020-2834-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 02/24/2020] [Indexed: 12/22/2022] Open
Abstract
Background Sub-optimal maternal lipid levels during pregnancy may be implicated in the pathophysiological mechanisms leading to low birth weight (LBW) and small-for-gestational-age (SGA). We aimed to determine whether maternal lipid levels across pregnancy were associated with birth weight and the risks of LBW and SGA in rural Gambia. Methods This secondary analysis of the ENID trial involved 573 pregnant women with term deliveries. Plasma levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), and triglycerides (TG) were analyzed at enrolment (mean (SD) = 13.9 (3.3) weeks gestation), 20 and 30 weeks gestation as continuous variables and percentile groups. Regression models with adjustment for confounders were used to examine associations between gestational lipid levels and birth weight and the risks of LBW (birth weight < 2500 g) and SGA (<10th percentile INTERGROWTH-21ST for birth weight). Results There were 7.9% LBW and 32.5% SGA infants. At enrolment, every unit increase in HDL-c was associated with a 2.7% (P = 0.011) reduction in relative risk of LBW. At 20 weeks gestation, every unit increase in TC levels was associated with a 1.3% reduction in relative risk of LBW (P = 0.002). Low (<10th percentile) HDL-c at enrolment or at 20 weeks gestation was associated with a 2.6 (P = 0.007) and 3.0 (P = 0.003) times greater risk of LBW, respectively, compared with referent (10th─90th) HDL-c. High (>90th percentile) LDL-c at 30 weeks gestation was associated with a 55% lower risk of SGA compared with referent LDL-c (P = 0.017). Increased levels of TC (β = 1.3, P = 0.027) at 20 weeks gestation and of TC (β = 1.2, P = 0.006) and LDL-c (β = 1.5, P = 0.002) at 30 weeks gestation were all associated with higher birth weight. Conclusions In rural Gambia, lipid levels during pregnancy were associated with infant birth weight and the risks of LBW and SGA. Associations varied by lipid class and changed across pregnancy, indicating an adaptive process by which maternal lipids may influence fetal growth and birth outcomes. Trial registration This trial was registered as ISRCTN49285450 on: 12/11/2009.
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Affiliation(s)
- Sandra G Okala
- Department of Women and Children's Health, King's College London, London, SE1 7EH, UK
| | - Ebrima A Sise
- MRC Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Fatou Sosseh
- MRC Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Andrew M Prentice
- MRC Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Laura A Woollett
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | - Sophie E Moore
- Department of Women and Children's Health, King's College London, London, SE1 7EH, UK. .,MRC Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia.
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Horne H, Holme AM, Roland MCP, Holm MB, Haugen G, Henriksen T, Michelsen TM. Maternal-fetal cholesterol transfer in human term pregnancies. Placenta 2019; 87:23-29. [PMID: 31541855 DOI: 10.1016/j.placenta.2019.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 08/16/2019] [Accepted: 09/02/2019] [Indexed: 12/21/2022]
Abstract
OBJECTIVES The extent to which the human term fetus utilizes cholesterol released from the placenta has remained elusive. Our aims were to estimate the net mass of cholesterol taken up by the uteroplacental unit, released by the placenta and taken up by the fetus. Thereby we aimed to explore the maternal-fetal cholesterol transfer and hypothesized that maternal levels and uteroplacental uptake were correlated to the fetal uptake of cholesterol. METHODS A cross-sectional in vivo study of 179 fasting, healthy women with uncomplicated singleton pregnancies. Blood flow in the uterine artery (n = 70) and umbilical vein (n = 125) was measured by Doppler ultrasound. Blood samples from the maternal radial artery, antecubital vein and uterine vein, and the umbilical artery and vein were obtained during cesarean section. Cholesterol was determined enzymatically. RESULTS We found a significant uteroplacental uptake (median [Q1,Q3]) of total (3.50 [-36.8,61.1]) and HDL cholesterol (6.69 [-3.78,17.9]) μmol/min, and a fetal uptake of HDL (8.07 [4.48,12.59]), LDL (5.97 [2.77,8.92]) and total cholesterol (13.2 [8.06,21.58]) μmol/min. Maternal cholesterol levels were not correlated to fetal uptake of cholesterol. There was a correlation between uteroplacental uptake of total (rho 0.35, p 0.003) and LDL cholesterol (rho 0.25, p 0.03) and the fetal uptake of LDL cholesterol from the umbilical circulation. The fetal uptake of cholesterol from HDL was higher than from LDL (p < 0.001). CONCLUSION Fetal cholesterol uptake is independent of maternal cholesterol levels, but related to the uteroplacental uptake of cholesterol from LDL. This suggests that the placenta influences maternal-fetal cholesterol transfer at term.
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Affiliation(s)
- Hildegunn Horne
- Department of Obstetrics, Division of Obstetrics and Gynecology, Oslo University Hospital, PO BOX 4950, 0424, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, PO BOX 1072, Blindern, 0316, Oslo, Norway.
| | - Ane Moe Holme
- Department of Obstetrics, Division of Obstetrics and Gynecology, Oslo University Hospital, PO BOX 4950, 0424, Oslo, Norway.
| | - Marie Cecilie Paasche Roland
- Department of Obstetrics, Division of Obstetrics and Gynecology, Oslo University Hospital, PO BOX 4950, 0424, Oslo, Norway; Norwegian Advisory Unit on Women's Health, Oslo University Hospital, PO BOX 4950, 0424, Oslo, Norway.
| | - Maia Blomhoff Holm
- Department of Obstetrics, Division of Obstetrics and Gynecology, Oslo University Hospital, PO BOX 4950, 0424, Oslo, Norway.
| | - Guttorm Haugen
- Institute of Clinical Medicine, University of Oslo, PO BOX 1072, Blindern, 0316, Oslo, Norway; Department of Fetal Medicine, Division of Obstetrics and Gynecology, Oslo University Hospital, PO BOX 4950, 0424, Oslo, Norway.
| | - Tore Henriksen
- Department of Obstetrics, Division of Obstetrics and Gynecology, Oslo University Hospital, PO BOX 4950, 0424, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, PO BOX 1072, Blindern, 0316, Oslo, Norway.
| | - Trond Melbye Michelsen
- Department of Obstetrics, Division of Obstetrics and Gynecology, Oslo University Hospital, PO BOX 4950, 0424, Oslo, Norway; Norwegian Advisory Unit on Women's Health, Oslo University Hospital, PO BOX 4950, 0424, Oslo, Norway.
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Placental secretion of apolipoprotein A1 and E: the anti-atherogenic impact of the placenta. Sci Rep 2019; 9:6225. [PMID: 30996342 PMCID: PMC6470155 DOI: 10.1038/s41598-019-42522-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 04/01/2019] [Indexed: 12/12/2022] Open
Abstract
High levels of atherogenic lipids in pregnancy are associated with health complications for the mother, the fetus and the newborn. As endocrine secretory tissue, the human placenta releases apolipoproteins (apos), particularly apoA1 and apoE. However, the magnitude and the directionality of the apo secretions remain unknown. We aimed to 1) determine the amount and orientation (apical-maternal versus basal-fetal) of placentally secreted apoA1 and apoE using human perfused placenta and primary trophoblast cell (PTC) culture, 2) compare apoA1 and apoE secretions of PTC with that of hepatocytes and 3) associate the obtained results with human blood levels by determining apoA1 and apoE concentrations in maternal and fetal serum samples. In perfused placenta and serum samples, apoA1 and apoE concentrations were significantly higher at the maternal compared to the fetal side. For apoE a similar trend was found in PTC. For apoA1, the secretion to the apical side declined over time while release to the basal side was stable resulting in significantly different apoA1 concentrations between both sides. Unexpectedly, PTC secreted significantly higher amounts of apoA1 and apoE compared to hepatocytes. Our data indicate that the placenta may play an important role in maternal and fetal cholesterol homeostasis via secretion of anti-atherogenic apos.
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Zanoni P, Velagapudi S, Yalcinkaya M, Rohrer L, von Eckardstein A. Endocytosis of lipoproteins. Atherosclerosis 2018; 275:273-295. [PMID: 29980055 DOI: 10.1016/j.atherosclerosis.2018.06.881] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/04/2018] [Accepted: 06/22/2018] [Indexed: 02/06/2023]
Abstract
During their metabolism, all lipoproteins undergo endocytosis, either to be degraded intracellularly, for example in hepatocytes or macrophages, or to be re-secreted, for example in the course of transcytosis by endothelial cells. Moreover, there are several examples of internalized lipoproteins sequestered intracellularly, possibly to exert intracellular functions, for example the cytolysis of trypanosoma. Endocytosis and the subsequent intracellular itinerary of lipoproteins hence are key areas for understanding the regulation of plasma lipid levels as well as the biological functions of lipoproteins. Indeed, the identification of the low-density lipoprotein (LDL)-receptor and the unraveling of its transcriptional regulation led to the elucidation of familial hypercholesterolemia as well as to the development of statins, the most successful therapeutics for lowering of cholesterol levels and risk of atherosclerotic cardiovascular diseases. Novel limiting factors of intracellular trafficking of LDL and the LDL receptor continue to be discovered and to provide drug targets such as PCSK9. Surprisingly, the receptors mediating endocytosis of high-density lipoproteins or lipoprotein(a) are still a matter of controversy or even new discovery. Finally, the receptors and mechanisms, which mediate the uptake of lipoproteins into non-degrading intracellular itineraries for re-secretion (transcytosis, retroendocytosis), storage, or execution of intracellular functions, are largely unknown.
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Affiliation(s)
- Paolo Zanoni
- Institute for Clinical Chemistry, University and University Hospital Zurich, Zurich, Switzerland; Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Srividya Velagapudi
- Institute for Clinical Chemistry, University and University Hospital Zurich, Zurich, Switzerland; Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Mustafa Yalcinkaya
- Institute for Clinical Chemistry, University and University Hospital Zurich, Zurich, Switzerland; Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Lucia Rohrer
- Institute for Clinical Chemistry, University and University Hospital Zurich, Zurich, Switzerland; Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Arnold von Eckardstein
- Institute for Clinical Chemistry, University and University Hospital Zurich, Zurich, Switzerland; Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.
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A Prospective Birth Cohort Study on Maternal Cholesterol Levels and Offspring Attention Deficit Hyperactivity Disorder: New Insight on Sex Differences. Brain Sci 2017; 8:brainsci8010003. [PMID: 29295472 PMCID: PMC5789334 DOI: 10.3390/brainsci8010003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 01/15/2023] Open
Abstract
Growing evidence suggests that maternal cholesterol levels are important in the offspring’s brain growth and development. Previous studies on cholesterols and brain functions were mostly in adults. We sought to examine the prospective association between maternal cholesterol levels and the risk of attention deficit hyperactivity disorder (ADHD) in the offspring. We analyzed data from the Boston Birth Cohort, enrolled at birth and followed from birth up to age 15 years. The final analyses included 1479 mother-infant pairs: 303 children with ADHD, and 1176 neurotypical children without clinician-diagnosed neurodevelopmental disorders. The median age of the first diagnosis of ADHD was seven years. The multiple logistic regression results showed that a low maternal high-density lipoprotein level (≤60 mg/dL) was associated with an increased risk of ADHD, compared to a higher maternal high-density lipoprotein level, after adjusting for pertinent covariables. A “J” shaped relationship was observed between triglycerides and ADHD risk. The associations with ADHD for maternal high-density lipoprotein and triglycerides were more pronounced among boys. The findings based on this predominantly urban low-income minority birth cohort raise a new mechanistic perspective for understanding the origins of ADHD and the gender differences and future targets in the prevention of ADHD.
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Long term betaine supplementation regulates genes involved in lipid and cholesterol metabolism of two muscles from an obese pig breed. Meat Sci 2017; 124:25-33. [DOI: 10.1016/j.meatsci.2016.10.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 10/20/2016] [Accepted: 10/24/2016] [Indexed: 12/15/2022]
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Maternal dietary betaine supplementation modifies hepatic expression of cholesterol metabolic genes via epigenetic mechanisms in newborn piglets. Br J Nutr 2014; 112:1459-68. [PMID: 25216241 DOI: 10.1017/s0007114514002402] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
To elucidate the effects of maternal dietary betaine supplementation on hepatic expression of cholesterol metabolic genes in newborn piglets and the involved epigenetic mechanisms, we fed gestational sows with control or betaine-supplemented diets (3 g/kg) throughout pregnancy. Neonatal piglets born to betaine-supplemented sows had higher serum methionine concentration and hepatic content of betaine, which was associated with significantly up-regulated hepatic expression of glycine N-methyltransferase. Prenatal betaine exposure increased hepatic cholesterol content and modified the hepatic expression of cholesterol metabolic genes in neonatal piglets. Sterol regulatory element-binding protein 2 was down-regulated at both mRNA and protein levels, while 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR) was down-regulated at the mRNA level, but up-regulated at the protein level, in betaine-exposed piglets. The transcriptional repression of HMGCR was associated with CpG island hypermethylation and higher repressive histone mark H3K27me3 (histone H3 lysine 27 trimethylation) on the promoter, whereas increased HMGCR protein content was associated with significantly decreased expression of miR-497. Furthermore, LDL receptor was significantly down-regulated at both mRNA and protein levels in the liver of betaine-exposed piglets, which was associated with promoter CpG hypermethylation. In addition, the expression of cholesterol-27α-hydroxylase (CYP27α1) was up-regulated at both mRNA and protein levels, while the expression of cholesterol-7α-hydroxylase (CYP7α1) was increased at the mRNA level, but unchanged at the protein level associated with increased expression of miR-181. These results indicate that maternal betaine supplementation increases hepatic cholesterol content in neonatal piglets through epigenetic regulations of cholesterol metabolic genes, which involve alterations in DNA and histone methylation and in the expression of microRNA targeting these genes.
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Yu Y, Luo GH, Zhang J, Jiang H, Wei J, Shi YP, Zhang XY, Xu N. Increased mRNA levels of apolipoprotein M and apolipoprotein AI in the placental tissues with fetal macrosomia. Arch Gynecol Obstet 2014; 291:299-303. [PMID: 25194312 DOI: 10.1007/s00404-014-3441-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 08/26/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE The present study examined mRNA levels of apolipoprotein M (apoM) and apolipoprotein AI (apoAI) in the term placental tissues obtained from 37 women with normal birth weight neonates and from 37 women with macrosomic neonates (birth body weight ≥4,000 g), and further discussed possible clinical significance of these observations. METHODS The mRNA levels of apoM and apoAI in the placental tissues were determined by the real time RT-PCR, which demonstrated that both apoM and apoAI mRNA levels were significantly higher in the placentas from macrosomia than those from normal birth. Moreover, we analyzed the overexpressions of apoM and apoAI with the clinical data. Meanwhile we examined several known risk factors of macrosomia including the mRNA levels of insulin-like growth factor I (IGF-I), IGF-II, insulin-like growth factor I receptor (IGF-IR) and IGF-IIR. RESULTS It demonstrated that apoM expression was significantly positively correlated to the placental weight, fetal birth weight, pregestational body mass index (BMI), weight gain during pregnancy, maternal weight, maternal BMI and the mRNA levels of IGF-IR as well as IGF-IIR. The apoAI mRNA level was statistically significantly correlated to the placental weight, fetal birth weight, IGF-I and IGF-IR mRNA levels. CONCLUSIONS Binary logistic regression analysis suggested that both apoM and apoAI mRNA may considered as independent risk factors for macrosomia. The clinical significance needs further investigation.
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Affiliation(s)
- Yang Yu
- Comprehensive Laboratory, Third Affiliated Hospital, Soochow University, Jiangsu, 213003, Changzhou, People's Republic of China,
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Affiliation(s)
- Wulf Palinski
- From the Department of Medicine, University of California San Diego, La Jolla, CA.
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Burke KA, Jauniaux E, Burton GJ, Cindrova-Davies T. Expression and immunolocalisation of the endocytic receptors megalin and cubilin in the human yolk sac and placenta across gestation. Placenta 2013; 34:1105-9. [PMID: 23978537 PMCID: PMC3820039 DOI: 10.1016/j.placenta.2013.08.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 07/31/2013] [Accepted: 08/05/2013] [Indexed: 11/04/2022]
Abstract
Megalin and cubilin are multifunctional endocytic receptors associated with many transporting epithelia. They play an essential role in transport of nutrients through the visceral yolk sac of rodents during embryogenesis. Here, we immunolocalise them to the endodermal layer of the human yolk sac, and to the syncytiotrophoblast and cytotrophoblast cells of placental villi. In villi, the protein level of both receptors increased with gestation. The mRNA for megalin remained constant, while that encoding cubilin increased with gestation. These results suggest megalin and cubilin may be important in human maternal–fetal transfer, and that they increase across gestation to facilitate this function.
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Affiliation(s)
- K A Burke
- Centre for Trophoblast Research, University of Cambridge, Cambridge, UK
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Chadwick AC, Sahoo D. Functional genomics of the human high-density lipoprotein receptor scavenger receptor BI: an old dog with new tricks. Curr Opin Endocrinol Diabetes Obes 2013; 20:124-31. [PMID: 23403740 PMCID: PMC3967407 DOI: 10.1097/med.0b013e32835ed575] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE OF REVIEW The athero-protective role of scavenger receptor BI (SR-BI) is primarily attributed to its ability to selectively transfer cholesteryl esters from high-density lipoproteins (HDLs) to the liver during reverse cholesterol transport (RCT). In this review, we highlight recent findings that reveal the impact of SR-BI on lipid levels and cardiovascular disease in humans. Moreover, additional responsibilities of SR-BI in modulating adrenal and platelet function, as well as female fertility in humans, are discussed. RECENT FINDINGS Heterozygote carriers of P297S, S112F and T175A-mutant SR-BI receptors were identified in patients with high HDL-cholesterol levels. HDL from P297S-SR-BI carriers was unable to mediate macrophage cholesterol efflux, whereas hepatocytes expressing P297S-SR-BI were unable to mediate the selective uptake of HDL-cholesteryl esters. S112F and T175A-mutant receptors exhibited similar impaired cholesterol transport functions in vitro. Reduced SR-BI function in P297S carriers was also associated with decreased steroidogenesis and altered platelet function. Further, human population studies identified SCARB1 variants associated with female infertility. SUMMARY Identification of SR-BI variants confirms the key role of this receptor in influencing lipid levels and RCT in humans. A deeper understanding of the contributions of SR-BI to steroidogenesis, platelet function and fertility is required in light of exploration of HDL-raising therapies aimed at reducing cardiovascular risk.
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Affiliation(s)
- Alexandra C. Chadwick
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Daisy Sahoo
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
- Department of Medicine, Division of Endocrinology, Metabolism & Clinical Nutrition, Milwaukee, WI, 53226, USA
- To whom correspondence should be addressed: H4930 Health Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, Phone: 1-414-955-7414; Fax: 1-414-456-6570,
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Baardman ME, Kerstjens-Frederikse WS, Berger RM, Bakker MK, Hofstra RM, Plösch T. The Role of Maternal-Fetal Cholesterol Transport in Early Fetal Life: Current Insights1. Biol Reprod 2013; 88:24. [DOI: 10.1095/biolreprod.112.102442] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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Maternal inheritance of familial hypercholesterolemia caused by the V408M low-density lipoprotein receptor mutation increases mortality. Atherosclerosis 2011; 219:690-3. [DOI: 10.1016/j.atherosclerosis.2011.08.039] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 08/01/2011] [Accepted: 08/24/2011] [Indexed: 11/18/2022]
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Rebholz SL, Burke KT, Yang Q, Tso P, Woollett LA. Dietary fat impacts fetal growth and metabolism: uptake of chylomicron remnant core lipids by the placenta. Am J Physiol Endocrinol Metab 2011; 301:E416-25. [PMID: 21586694 PMCID: PMC3154537 DOI: 10.1152/ajpendo.00619.2010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The fetus requires significant energy for growth and development. Although glucose is a major source of energy for the fetus, other maternal nutrients also appear to promote growth. Thus, the goal of these studies was to determine whether triglyceride-rich remnants are taken up by the placenta and whether maternal dietary lipids, independently of adiposity, can impact fetal growth. To accomplish our first goal, chylomicron particles were duallly labeled with cholesteryl ester and triglycerides. The placenta took up remnant particles/core lipids at rates greater than adipose tissue and skeletal muscle but less than the liver. Although the placenta expresses apoE receptors, uptake of chylomicron remnants and/or core lipids can occur independently of apoE. To determine the impact of dietary lipid on fetal growth, independent of maternal adiposity, females were fed high-fat diets (HFD) for 1 mo; there was no change in adiposity or leptin levels prior to or during pregnancy of dams fed HFD. Fetal masses were greater in dams fed HFD, and mRNA levels of proteins involved in fatty acid oxidation (CPT I, PPARα), but not glucose oxidation (pyruvate kinase) or other regulatory processes (HNF-4α, LXR), were increased with maternal dietary fat. There was also no change in mRNA levels of proteins involved in placental glucose and fatty acid transport, and GLUT1 protein levels in microvillous membranes were similar in placentas of dams fed either diet. Thus, the ability of the placenta to take up chylomicron remnant core lipids likely contributes to accelerated fetal growth in females fed high fat diets.
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Affiliation(s)
- Sandra L Rebholz
- Department of Pathology and Laboratory Medicine, University of Cincinnati Medical School, 2180 E. Galbraith Rd., Cincinnati, OH 45237, USA
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Misra VK, Trudeau S, Perni U. Maternal serum lipids during pregnancy and infant birth weight: the influence of prepregnancy BMI. Obesity (Silver Spring) 2011; 19:1476-81. [PMID: 21394096 DOI: 10.1038/oby.2011.43] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Maternal obesity may be associated with metabolic factors that affect the intrauterine environment, fetal growth, and the offspring's long-term risk for chronic disease. Among these factors, maternal serum lipids play a particularly important role. Our objective was to estimate the influence of variation in maternal serum lipid levels on variation in infant birth weight (BW) in overweight/obese and normal weight women. In a prospective cohort of 143 gravidas, we measured maternal serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) at 6-10, 10-14, 16-20, 22-26, and 32-36 weeks gestation. Effects of maternal serum lipid levels on infant BW adjusted for gestational age at delivery (aBW) were analyzed using linear regression models. In analyses stratified by maternal prepregnancy BMI categorized as normal (≤25.0 kg/m(2)) and overweight/obese (>25.0 kg/m(2)), we found a significant (P < 0.05) inverse association between aBW and HDL-C at all time points starting at 10 weeks gestation in overweight/obese women. No significant effect was found in normal weight women. In contrast, increased maternal serum TG was significantly associated with increased aBW only for normal weight women at 10-14 and 22-26 weeks gestation. Variation in aBW is not associated with variation in maternal serum TC or LDL-C for either stratum at any time point. We postulate that such differences may be involved in the "physiological programming" that influences later risk of chronic disease in the infants of overweight/obese mothers.
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Affiliation(s)
- Vinod K Misra
- Department of Pediatrics, Division of Genetic and Metabolic Disorders, Wayne State University School of Medicine, Detroit, Michigan, USA.
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Woollett LA. Review: Transport of maternal cholesterol to the fetal circulation. Placenta 2011; 32 Suppl 2:S218-21. [PMID: 21300403 DOI: 10.1016/j.placenta.2011.01.011] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 01/12/2011] [Accepted: 01/13/2011] [Indexed: 11/19/2022]
Abstract
Data obtained from recent studies in humans, rodents, and cell culture demonstrate that circulating maternal cholesterol can be transported to the fetus. The two major cell types responsible for the transport are trophoblasts and endothelial cells of the fetoplacental vasculature. Maternal lipoprotein-cholesterol is initially taken up by trophoblasts via receptor-mediated and receptor-independent processes, is transported by any number of the sterol transport proteins expressed by cells, and is effluxed or secreted out of the basal side via protein-mediated processes or by aqueous diffusion. This cholesterol is then taken up by the endothelium and effluxed to acceptors within the fetal circulation. The ability to manipulate the mass of maternal cholesterol that is taken up by the placenta and crosses to the fetus could positively impact development of fetuses affected with the Smith-Lemli-Opitz Syndrome (SLOS) that have reduced ability to synthesize cholesterol and possibly impact growth of fetuses unaffected by SLOS but with low birthweights.
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Affiliation(s)
- L A Woollett
- University of Cincinnati, Metabolic Diseases Institute, Department of Pathology, Cincinnati, OH 45236-507, USA.
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Argov- Argaman N, Smilowitz JT, Bricarello DA, Barboza M, Lerno L, Froehlich JW, Lee H, Zivkovic AM, Lemay DG, Freeman S, Lebrilla CB, Parikh AN, German JB. Lactosomes: structural and compositional classification of unique nanometer-sized protein lipid particles of human milk. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:11234-42. [PMID: 20925428 PMCID: PMC3039697 DOI: 10.1021/jf102495s] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Milk fat globules (MFGs) are accepted primarily as triacylglycerol delivery systems. The identification of nanometer-sized lipid-protein particles termed "lactosomes" that do not contain triacylglycerol raises the question of their possible functions. MFGs were isolated by slow centrifugation, and lactosomes were isolated by ultracentrifugation at a density equivalent to plasma high-density lipoproteins (HDL) (d > 1.063 g/mL) from human milk obtained from six volunteers at different lactation stages. Isolated lactosomes were analyzed and compared with MFGs for their size distribution, lipidome, proteome, and functional activity. Lactosomes from early milk, day 8, were found to be similar in size as those from mature milk >28 days, averaging ∼ 25 nm in diameter. In total, 97 nonredundant proteins were identified in the MFG and lactosome fractions, 46 of which were unique to the MFG fraction and 29 of which were unique to the lactosome fraction. The proteins identified in the lactosome and MFG fractions were enriched with proteins identified with immunomodulatory pathways. Unlike MFGs and GM1-laden reconstituted HDL that served as a positive control, lactosomal binding capacity to cholera toxin was weak. Lipidomic analyses found that lactosomes were devoid of triacylglycerol and gangliosides, unlike MFGs, but rich in a variety of phospholipid species. The data found differences in structure, composition, and function between lactosomes and MFG, suggesting that these two particles are derived from different biosynthetic and/or secretory pathways. The results reveal a bioactive lipid-protein, nanometer-length scale particle that is secreted into milk not to supply energy to the infant but to play unique, protective, and regulatory roles.
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Affiliation(s)
- Nurit Argov- Argaman
- Department of Animal Science, the Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, PO Box 12, Rehovot 76100
| | | | | | - Mariana Barboza
- Department of Chemistry, University of California, Davis, CA 95616
| | - Larry Lerno
- Department of Chemistry, University of California, Davis, CA 95616
| | | | - Hyeyoung Lee
- Dept of Food Science and Technology, University of California, Davis, CA 95616
| | - Angela M. Zivkovic
- Dept of Food Science and Technology, University of California, Davis, CA 95616
| | - Danielle G. Lemay
- Dept of Food Science and Technology, University of California, Davis, CA 95616
| | - Samara Freeman
- Dept of Food Science and Technology, University of California, Davis, CA 95616
| | | | - Atul N. Parikh
- Department of Applied Science, University of California, Davis, CA 95616
| | - J. Bruce German
- Dept of Food Science and Technology, University of California, Davis, CA 95616
- Nestle Research Center, Lausanne, Switzerland
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Plösch T, Gellhaus A, van Straten EME, Wolf N, Huijkman NCA, Schmidt M, Dunk CE, Kuipers F, Winterhager E. The liver X receptor (LXR) and its target gene ABCA1 are regulated upon low oxygen in human trophoblast cells: a reason for alterations in preeclampsia? Placenta 2010; 31:910-8. [PMID: 20709391 DOI: 10.1016/j.placenta.2010.07.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 07/08/2010] [Accepted: 07/20/2010] [Indexed: 11/19/2022]
Abstract
OBJECTIVES The Liver X receptors (LXR) alpha and beta and their target genes such as the ATP-binding cassette (ABC) transporters have been shown to be crucially involved in the regulation of cellular cholesterol homeostasis. The aim of this study was to characterize the role of LXR alpha/beta in the human placenta under normal physiological circumstances and in preeclampsia. STUDY DESIGN We investigated the expression pattern of the LXRs and their target genes in the human placenta during normal pregnancy and in preeclampsia. Placental explants and cell lines were studied under different oxygen levels and pharmacological LXR agonists. MAIN OUTCOME MEASURES Gene expressions (Taqman PCR) and protein levels (Western Blot) were combined with immunohistochemistry to analyze the expression of LXR and its target genes. RESULTS In the human placenta, LXRA and LXRB expression increased during normal pregnancy. This was paralleled by the expression of their prototypical target genes, e.g., the cholesterol transporter ABCA1. Interestingly, early-onset preeclamptic placentae revealed a significant upregulation of ABCA1. Culture of JAr trophoblast cells and human first trimester placental explants under low oxygen lead to increased expression of LXRA and ABCA1 which was further enhanced by the LXR agonist T0901317. CONCLUSIONS LXRA together with ABCA1 are specifically expressed in the human placenta and can be regulated by hypoxia. Deregulation of this system in early preeclampsia might be the result of placental hypoxia and hence might have consequences for maternal-fetal cholesterol transport.
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Affiliation(s)
- T Plösch
- Dept Pediatrics, University Medical Center Groningen, University of Groningen, Center for Liver, Digestive and Metabolic Diseases, Groningen, The Netherlands.
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Bhattacharjee J, Ietta F, Giacomello E, Bechi N, Romagnoli R, Fava A, Paulesu L. Expression and localization of ATP binding cassette transporter A1 (ABCA1) in first trimester and term human placenta. Placenta 2010; 31:423-30. [PMID: 20338636 DOI: 10.1016/j.placenta.2010.02.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 02/22/2010] [Accepted: 02/23/2010] [Indexed: 01/23/2023]
Abstract
ATP binding cassette transporter A1 (ABCA1) is a membrane transporter which performs cellular efflux of cholesterol and phospholipid. ABCA1's cholesterol transporting role in human placenta appears to be crucial for normal fetal development. Despite the critical importance of cholesterol in fetal development, expression of ABCA1 in the human placenta throughout gestation and its specific cellular localization have not been known yet. We therefore investigated ABCA1 expression in human placenta at first trimester and term by western blot and quantitative real-time PCR (qRT-PCR) analysis. Furthermore, its localization was investigated by immunohistochemistry and confocal microscopy. Expression of ABCA1 did not differ significantly between first trimester and term placenta at both protein and mRNA levels. Immunohistochemical data demonstrated that ABCA1 was widely localized in the villous and extravillous cytotrophoblast as well as in some stromal and endothelial cells. Confocal microscopy imaging data showed that ABCA1 was localized largely at the basolateral and to some extent at the apical side of first trimester villous cytotrophoblast cell membranes. Placental expression of ABCA1 throughout the gestation and its specific cellular localization indicate that this transporter may play an important role in materno-fetal cholesterol transfer.
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Affiliation(s)
- J Bhattacharjee
- Department of Physiology, University of Siena, Via A. Moro, 53100 Siena, Italy
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Avis HJ, Hutten BA, Twickler MTB, Kastelein JJP, van der Post JAM, Stalenhoef AF, Vissers MN. Pregnancy in women suffering from familial hypercholesterolemia: a harmful period for both mother and newborn? Curr Opin Lipidol 2009; 20:484-90. [PMID: 19741526 DOI: 10.1097/mol.0b013e3283319127] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW The present review aims to highlight the consequences for mother and child of profound hypercholesterolemia during pregnancy of women with familial hypercholesterolemia. RECENT FINDINGS Familial hypercholesterolemia is increasingly diagnosed in younger patients due to the existence of screening programs and more widespread cholesterol testing. Increasing numbers of young female patients with familial hypercholesterolemia raise the issue of pregnancy and its consequences for the familial hypercholesterolemia patient herself but also for her offspring. When pregnancy is considered, lipid-lowering drugs are often discontinued because of the fear for teratogenic effects. The evidence for teratogenesis associated with statin use is scant and conflicting. On the other hand, several studies do suggest that pronounced hypercholesterolemia during pregnancy has adverse effects on both fetus and mother. In fact, human and animal studies reveal an enhanced tendency toward atherosclerosis in the offspring of women who suffer from hypercholesterolemia during pregnancy. In animal studies, some evidence exists that this can be reversed by treatment with lipid-lowering and antioxidative agents. Until today, however, no human studies exist that have evaluated efficacy or safety of lipid-lowering interventions in pregnant women with familial hypercholesterolemia. SUMMARY Altogether, the suggested relationship between severe hypercholesterolemia and enhanced atherosclerosis in offspring and possibly the mother warrants further confirmation and, consequently, studies that focus on therapeutic strategies that can safely lower cholesterol levels during pregnancy in these women.
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Affiliation(s)
- Hans J Avis
- Department of Vascular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands
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30
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Burke KT, Colvin PL, Myatt L, Graf GA, Schroeder F, Woollett LA. Transport of maternal cholesterol to the fetus is affected by maternal plasma cholesterol concentrations in the golden Syrian hamster. J Lipid Res 2009; 50:1146-55. [PMID: 19122238 DOI: 10.1194/jlr.m800538-jlr200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The fetus has a high requirement for cholesterol and synthesizes cholesterol at elevated rates. Recent studies suggest that fetal cholesterol also can be obtained from exogenous sources. The purpose of the current study was to examine the transport of maternal cholesterol to the fetus and determine the mechanism responsible for any cholesterol-driven changes in transport. Studies were completed in pregnant hamsters with normal and elevated plasma cholesterol concentrations. Cholesterol feeding resulted in a 3.1-fold increase in the amount of LDL-cholesterol taken up by the fetus and a 2.4-fold increase in the amount of HDL-cholesterol taken up. LDL-cholesterol was transported to the fetus primarily by the placenta, and HDL-cholesterol was transported by the yolk sac and placenta. Several proteins associated with sterol transport and efflux, including those induced by activated liver X receptor, were expressed in hamster and human placentas: NPC1, NPC1L1, ABCA2, SCP-x, and ABCG1, but not ABCG8. NPC1L1 was the only protein increased in hypercholesterolemic placentas. Thus, increasing maternal lipoprotein-cholesterol concentrations can enhance transport of maternal cholesterol to the fetus, leading to 1) increased movement of cholesterol down a concentration gradient in the placenta, 2) increased lipoprotein secretion from the yolk sac (shown previously), and possibly 3) increased placental NPC1L1 expression.
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Affiliation(s)
- Katie T Burke
- Department of Pathology and Laboratory Medicine, University of Cincinnati Medical School, Cincinnati, OH 45237, USA
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31
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Abstract
The development of a single-celled fertilized egg, through the blastocyst stage of a ball of cells and the embryonic stage when almost all organ systems begin to develop, and finally to the fetal stage where growth and physiological maturation occurs, is a complex and multifaceted process. A change in metabolism during gestation, especially when organogenesis occurs, can lead to abnormal development and congenital defects. Although many studies have described the roles of specific proteins in development, the roles of specific lipids, such as sterols, have not been studied as intensely. Sterol's functions in development range from being a structural component of membranes to regulating the patterning of the forebrain through sonic hedgehog to regulating expression of key proteins involved in metabolic processes. This review focuses on the roles of sterols in embryonic and fetal development and metabolism. Potential sources of cholesterol for the fetus and embryo are also discussed.
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Affiliation(s)
- Laura A Woollett
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45237, USA.
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Dugué-Pujol S, Rousset X, Château D, Pastier D, Klein C, Demeurie J, Cywiner-Golenzer C, Chabert M, Verroust P, Chambaz J, Châtelet FP, Kalopissis AD. Apolipoprotein A-II is catabolized in the kidney as a function of its plasma concentration. J Lipid Res 2007; 48:2151-61. [PMID: 17652309 DOI: 10.1194/jlr.m700089-jlr200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We investigated in vivo catabolism of apolipoprotein A-II (apo A-II), a major determinant of plasma HDL levels. Like apoA-I, murine apoA-II (mapoA-II) and human apoA-II (hapoA-II) were reabsorbed in the first segment of kidney proximal tubules of control and hapoA-II-transgenic mice, respectively. ApoA-II colocalized in brush border membranes with cubilin and megalin (the apoA-I receptor and coreceptor, respectively), with mapoA-I in intracellular vesicles of tubular epithelial cells, and was targeted to lysosomes, suggestive of degradation. By use of three transgenic lines with plasma hapoA-II concentrations ranging from normal to three times higher, we established an association between plasma concentration and renal catabolism of hapoA-II. HapoA-II was rapidly internalized in yolk sac epithelial cells expressing high levels of cubilin and megalin, colocalized with cubilin and megalin on the cell surface, and effectively competed with apoA-I for uptake, which was inhibitable by anti-cubilin antibodies. Kidney cortical cells that only express megalin internalized LDL but not apoA-II, apoA-I, or HDL, suggesting that megalin is not an apoA-II receptor. We show that apoA-II is efficiently reabsorbed in kidney proximal tubules in relation to its plasma concentration.
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Affiliation(s)
- Sonia Dugué-Pujol
- Institut National de la Santé et de la Recherche Médicale, U872, Equipe 6, Paris, France
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Plösch T, van Straten EME, Kuipers F. Cholesterol Transport by the Placenta: Placental Liver X Receptor Activity as a Modulator of Fetal Cholesterol Metabolism? Placenta 2007; 28:604-10. [PMID: 17141866 DOI: 10.1016/j.placenta.2006.10.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Revised: 10/17/2006] [Accepted: 10/18/2006] [Indexed: 11/30/2022]
Abstract
Cholesterol is an important sterol in mammals. Defects in cholesterol synthesis or intracellular routing have devastating consequences already in utero: the Smith-Lemli-Opitz syndrome, desmosterolosis and Niemann-Pick C1 disease provide examples of severe human inherited diseases caused by mutations in cholesterol metabolism genes. On the other hand, elevated plasma cholesterol concentrations are associated with the development of atherosclerosis which represents a major health risk in Western societies. Moreover, several studies indicate that development of atherosclerosis may already start during fetal life. Hence, a carefully balanced regulation of cholesterol metabolism appears of critical importance for both the development of the fetus and health of the adult. In the adult, the liver X receptor is a key regulator of cholesterol metabolism. Its target genes regulate cellular cholesterol efflux and thereby modulate whole-body cholesterol fluxes. LXR and several of its target genes have recently been demonstrated to be expressed in the placenta, which would provide a means to control delivery of maternal cholesterol to the fetus. Here we discuss the potential role of the placenta in the regulation of fetal cholesterol homeostasis and strategies to influence maternal-fetal cholesterol transfer.
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Affiliation(s)
- T Plösch
- Center for Liver, Digestive and Metabolic Diseases, Laboratory of Pediatrics, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands.
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Ethier-Chiasson M, Duchesne A, Forest JC, Giguère Y, Masse A, Mounier C, Lafond J. Influence of maternal lipid profile on placental protein expression of LDLr and SR-BI. Biochem Biophys Res Commun 2007; 359:8-14. [PMID: 17531953 DOI: 10.1016/j.bbrc.2007.05.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Accepted: 05/01/2007] [Indexed: 12/27/2022]
Abstract
Maternal hyperlipidemia is a characteristic feature during pregnancy, it has been reported that modification of the maternal lipid profile can induce disturbance during pregnancy. In this study, we evaluated the impact of maternal lipid profile on the placental protein expression of two major receptors in cholesterol metabolism, the low density lipoprotein receptor (LDLr) and the scavenger receptor type B1 (SR-B1). We demonstrate an increase in the level of maternal total circulating cholesterol leads to a significant decrease in the level of the LDLr protein expression, while the level of the SR-BI expression remains unchanged. A similar change, for LDLr, is observed in association with the maternal pre-pregnancy body mass index and weight gain. Our data suggest that the LDLr plays a role in regulating cholesterol delivered to the baby from the placenta.
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Affiliation(s)
- M Ethier-Chiasson
- Laboratoire de Physiologie Materno-Foetale, Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-ville, Montréal, Que., Canada H3C 3P8
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Abstract
Vitamins A and E are essential, naturally occurring, fat-soluble nutrients that are involved in several important biological processes such as immunity, protection against tissue damage, reproduction, growth and development. They are extremely important during the early stages of life and must be transferred adequately to the young during gestation and lactation. The present article presents an overview of their biological functions, metabolism and dynamics of transfer to offspring in mammals. Among other topics, the review focuses on the biochemical aspects of their intestinal absorption, blood transport, tissue uptake, storage and catabolism. It also describes their different roles as well as their use as preventive and therapeutic agents. Finally, the mechanisms involved in their transfer during gestation and lactation are discussed.
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Affiliation(s)
- C Debier
- Institut des Sciences de la Vie, Unité de Biochimie de la Nutrition, Université catholique de Louvain, Croix du Sud 2/8, B-1348 Louvain-la-Neuve, Belgium.
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36
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Wadsack C, Tabano S, Maier A, Hiden U, Alvino G, Cozzi V, Hüttinger M, Schneider WJ, Lang U, Cetin I, Desoye G. Intrauterine growth restriction is associated with alterations in placental lipoprotein receptors and maternal lipoprotein composition. Am J Physiol Endocrinol Metab 2007; 292:E476-84. [PMID: 17003234 DOI: 10.1152/ajpendo.00547.2005] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Among other factors, fetal growth requires maternal supply of cholesterol. Cellular cholesterol uptake is mainly mediated by the LDL receptor (LDL-R) and the scavenger receptor family. We hypothesized that expression levels of key receptors of these families were regulated differently in placentas from IUGR pregnancies with varying degrees of severity. Third-trimester placentas from IUGR pregnancies with (IUGR-S) and without (IUGR-M) fetal hemodynamic changes and from control (AGA) pregnancies were studied. LDL-R, LDL-R-related protein (LRP-1), and scavenger receptor class B type I (SR-BI) mRNA and protein levels were measured. Cholesterol concentration and composition of lipoproteins were analyzed enzymatically and by lipid electrophoresis, respectively, in maternal and umbilical cord blood. LDL-R mRNA levels in IUGR-M were similar to AGA but lower (P < 0.05) in IUGR-S. In contrast, LDL-R protein was twofold (IUGR-M) and 1.8-fold (IUGR-S) higher (P < 0.05) than in the AGA group. LRP-1 mRNA and protein levels were not altered in the IUGR cases. SR-BI mRNA was unchanged in IUGR, but protein levels were lower (P < 0.05) in IUGR-S than in the other groups. Maternal plasma concentrations of LDL cholesterol were higher (P < 0.05) in the AGA group (188.5 +/- 23.6 mg/dl) than in the IUGR-S group (154.2 +/- 26.1). Electrophoretic mobility of the LDL fraction in maternal plasma demonstrated significant changes in migration toward higher values (AGA 0.95 +/- 0.06, IUGR-M 1.12 +/- 0.11, P < 0.001; IUGR-S 1.28 +/- 0.20, P = 0.002). We conclude that LDL-R and SR-BI levels are altered in IUGR pregnancies. These differences were associated with changes in LDL, but not HDL, mobility and cholesterol concentration in maternal circulation.
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Affiliation(s)
- Christian Wadsack
- Clinic of Obstetrics and Gynecology, Medical University of Graz, Auenbruggerplatz 14, A-8036 Graz, Austria.
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37
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Abstract
Vitamin E is a fat-soluble nutrient that is extremely important during the early stages of life, from the time of conception to the postnatal development of the infant. The mechanisms involved in its placental and mammary uptake appear to be allowed by the presence of lipoprotein receptors (LDL-receptor, VLDL-receptor, scavenger receptor class B type I) together with lipoprotein lipase at the placental and mammary barriers. In addition, alpha-tocopherol transfer protein has been described as playing an essential role in the selective transfer of RRR-alpha-tocopherol across the placenta. Lower alpha-tocopherol concentrations are found in cord blood as compared to maternal circulation. The ingestion of colostrum which contains very high levels of vitamin E is therefore of utmost importance to supply the newborn with an essential defense against oxygen toxicity. Pregnancy is sometimes associated with complications that may lead to a premature delivery of the baby. Preterm infants are usually facing an oxidative stress that is among others related to a deficiency in alpha-tocopherol, as it accumulates mainly during the third trimester of pregnancy. Despite vitamin E supplementation, preterm infants usually require significantly longer to replenish their serum alpha-tocopherol levels than full-term infants. The use of vitamin E as a therapeutic agent in preeclampsia, which induces high maternal and fetal morbidity and mortality, has been discussed in numerous papers. This disorder is indeed associated with an important oxidative stress in the placenta and maternal circulation. However, the most recent studies did not show a beneficial effect of vitamin E administration in this pathology.
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Affiliation(s)
- Cathy Debier
- Institut des Sciences de la Vie, Unité de Biochimie de la Nutrition, Université Catholique de Louvain, Croix du Sud 2/8, B-1348 Louvain-la-Neuve, Belgium
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Lopez D, McLean MP. Estrogen regulation of the scavenger receptor class B gene: Anti-atherogenic or steroidogenic, is there a priority? Mol Cell Endocrinol 2006; 247:22-33. [PMID: 16297529 DOI: 10.1016/j.mce.2005.10.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Revised: 10/13/2005] [Accepted: 10/13/2005] [Indexed: 02/06/2023]
Abstract
High density lipoprotein (HDL) participates in reverse cholesterol transport and in the delivery of cholesterol to the liver and steroidogenic tissues by a mechanism called "selective lipid uptake" which is mediated by the HDL receptor, scavenger receptor B type I (SR-BI). Overexpression of SR-BI suppresses atherosclerosis by increasing reverse cholesterol transport. In contrast, genetic ablation of SR-BI has a negative effect on cardiovascular physiology in both males and females and a gender specific negative impact on female fertility. Cholesterol is essential for mammalian embryonic development as a necessary component of cell membranes and as a substrate for steroidogenesis. The SR-BI receptor is highly expressed in the human placenta allowing the growing fetus to obtain a considerable portion of cholesterol from maternal lipoproteins. Estrogen, which plays an important role in maintaining pregnancy, has been shown to enhance plasma HDL levels and promote reverse cholesterol transport. Since SR-BI is the major determinant of serum HDL levels, direct regulation of the SR-BI gene by estrogen is theorized. The objective of this manuscript is to summarize the current information related to estrogen regulation of the gene that codes for the SR-BI receptor.
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Affiliation(s)
- Dayami Lopez
- Department of Obstetrics & Gynecology, University of South Florida, College of Medicine, 12901 Bruce B Downs Boulevard, MDC 37, Tampa, FL 33612, USA
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39
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Woollett LA. Maternal cholesterol in fetal development: transport of cholesterol from the maternal to the fetal circulation. Am J Clin Nutr 2005; 82:1155-61. [PMID: 16332646 DOI: 10.1093/ajcn/82.6.1155] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cholesterol is required for fetal development. Data obtained from recent studies in humans, rodents, and cell cultures showed that circulating maternal cholesterol can affect fetal metabolism and sterol accretion. Recent studies in our laboratory showed that the efflux of cholesterol from the basolateral side of the placental cells and the secretion of cholesterol from endodermal yolk sac cells to the fetal circulation can be regulated. The ability to manipulate the mass of maternal cholesterol that crosses to the fetus could result in a dramatic improvement in the development of fetuses that lack the ability to synthesize cholesterol, such as those with Smith-Lemli-Opitz syndrome. On the other hand, it could also accelerate the development of various age-related diseases, such as atherosclerosis.
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Affiliation(s)
- Laura A Woollett
- Department of Pathology, 2120 East Galbraith Road, Genome Research Institute, University of Cincinnati, Cincinnati, OH 45236-0507, USA.
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40
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Hayden Lichtenberg M, Wilke CS, McConihay JA, Granholm NA, Woollett LA. Yolk sac cholesteryl ester secretion rates can be manipulated in the Golden Syrian hamster: effect of yolk sac cholesterol concentrations. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1735:214-21. [PMID: 16043393 DOI: 10.1016/j.bbalip.2005.05.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2005] [Revised: 05/16/2005] [Accepted: 05/31/2005] [Indexed: 11/15/2022]
Abstract
The yolk sac is one of two extra-embryonic fetal tissues that separates the fetal and maternal circulations. The yolk sac can secrete lipoprotein particles to the vitelline vessels, which supply yolk sac-derived nutrients to the embryo. The amount and composition of lipoproteins secreted from the rat yolk sac can be manipulated by fatty acid content and gestational age. The goals of the current studies were to determine, first, if tissue cholesterol concentration could mediate cholesterol secretion rate from the yolk sac and, second, if some of the secreted cholesterol could be derived from the maternal circulation. Golden Syrian hamsters were fed 2% added cholesterol to increase the yolk sac cholesterol concentration. Yolk sac explants secreted similar amounts of triglyceride and apolipoproteins B and E into the media regardless of yolk sac cholesterol concentration. In contrast, yolk sacs with greater cholesterol concentrations secreted 2.3-fold more cholesterol into the media as compared to control yolk sacs; the increase was found mostly as cholesteryl ester. At least part of the secreted cholesterol was maternally derived. These data demonstrate that yolk sac cholesterol concentration influences cholesterol secretion rates, and that at least some of the cholesterol secreted originates from the maternal circulation.
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Affiliation(s)
- M Hayden Lichtenberg
- Department of Pathology and Laboratory Medicine, University of Cincinnati, OH 45237, USA
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41
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Abstract
Cholesterol is essential for antenatal development. However, the transport of maternal cholesterol to the embryo has not been sufficiently studied, and that to the fetus is still controversial. To this end, a 1 mg dose of [3,4-(13)C(2)]cholesterol was injected daily into pregnant mice and the labeled cholesterol was measured by gas chromatography-mass spectrometry. After venous injections from days 10 to 17 of gestation, [(13)C]cholesterol levels in total ((12)C and (13)C) cholesterol were increased to 5.1% and 2.8% in maternal and fetal plasma, respectively. Labeled cholesterol was identified in the liver, kidneys, and intestines, but not in the brain, of the fetus. After injections from days 1 to 8, [(13)C]cholesterol levels were increased to 12.4% and 8.0% of total cholesterol in maternal plasma and the embryo, respectively. The level of 11.5% in the yolk sac was higher than that in the embryo. Intrauterine transfer of maternal cholesterol to the embryo as well as the fetus was evident in mice, and both the placenta and the yolk sac appear to be sites of intermediate passage in murine pregnancy.
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Affiliation(s)
- Shumi Yoshida
- Graduate School of Medicine, Osaka University, Suita 565-0871, Japan.
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42
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Assémat E, Vinot S, Gofflot F, Linsel-Nitschke P, Illien F, Châtelet F, Verroust P, Louvet-Vallée S, Rinninger F, Kozyraki R. Expression and role of cubilin in the internalization of nutrients during the peri-implantation development of the rodent embryo. Biol Reprod 2004; 72:1079-86. [PMID: 15616221 DOI: 10.1095/biolreprod.104.036913] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Histiotrophic nutrition is essential during the peri-implantation development in rodents, but little is known about receptors involved in protein and lipid endocytosis derived from the endometrium and the uterine glands. Previous studies suggested that cubilin, a multiligand receptor for vitamin, iron, and protein uptake in the adult, might be important in this process, but the onset of its expression and function is not known. In this study, we analyzed the expression of cubilin in the pre- and early post-implantation rodent embryo and tested its potential function in protein and cholesterol uptake. Using morphological and Western blot analysis, we showed that cubilin first appeared at the eight-cell stage. It was expressed by the maternal-fetal interfaces, trophectoderm and visceral endoderm, but also by the future neuroepithelial cells and the developing neural tube. At all these sites, cubilin was localized at the apical pole of the cells exposed to the maternal environment or to the amniotic and neural tube cavities, and had a very similar distribution to megalin, a member of the LDLR gene family and a coreceptor for cubilin in adult tissues. To analyze cubilin function, we followed endocytosis of apolipoprotein A-I and HDL cholesterol, nutrients normally present in the uterine glands and essential for embryonic growth. We showed that internalization of both ligands was cubilin dependent during the early rodent gestation. In conclusion, the early cubilin expression and its function in protein and cholesterol uptake suggest an important role for cubilin in the development of the peri-implantation embryo.
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Affiliation(s)
- Emeline Assémat
- Inserm, UMR 538, Faculté de Médecine Saint-Antoine, Paris, France
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Ishida T, Hatae T, Nishi N, Araki N, Hamasaki M. Immunocytochemical analysis of cubilin-mediated endocytosis of high density lipoproteins (HDL) in epithelial cells of the rat visceral yolk sac. Cell Tissue Res 2004; 318:533-43. [PMID: 15578272 DOI: 10.1007/s00441-004-0962-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2004] [Accepted: 07/31/2004] [Indexed: 11/24/2022]
Abstract
Cubilin was recently shown to function as an endocytic receptor for high density lipoprotein (HDL) holoparticles and apolipoprotein A-I (apo A-I), the main protein constituent of HDL. In the present study, we analyzed the distribution and intracellular trafficking of cubilin and HDL in rat visceral yolk sac epithelial cells. After epithelial cells were loaded with apolipoprotein E-free HDL for 30 min in vitro, double immunofluorescence showed that the apical cytoplasm of the cells was strongly stained with anti-cubilin antibodies and anti-apo A-I/HDL. Furthermore, double immunogold electron-microscopic observations revealed the distinct localization of cubilin and HDL in endocytic vacuoles. In early endosomes, both were colocalized on the membrane. Although, in late endosomes, cubilin was also localized on the membrane, HDL was mainly located in the matrix. Both were found in the matrix in lysosomes. In addition, cubilin was markedly localized in apical tubules (ATs), which are generally accepted as being receptor recycling compartments. Thus, HDL is internalized through cubilin-mediated endocytosis and is finally transported to lysosomes. By contrast, cubilin is mainly translocated to ATs for recycling, although some of the cubilin is degraded in lysosomes. Quantitative analysis further revealed that cubilin was not concentrated on the membranes of ATs, although it accumulated in the AT area. Some HDL were also observed in the AT area. These findings suggest that the translocation of cubilin and HDL to ATs from early endosomes occurs through a simple sorting mechanism based on the geometry of these compartments and the bulk membrane and volume flow.
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Affiliation(s)
- Tetsuya Ishida
- Department of Histology and Cell Biology, School of Medicine, Kagawa University, Miki, 761-0793, Kagawa, Japan.
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44
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Kim JG, Vallet JL, Nonneman D, Christenson RK. Molecular cloning and endometrial expression of porcine high density lipoprotein receptor SR-BI during the estrous cycle and early pregnancy. Mol Cell Endocrinol 2004; 222:105-12. [PMID: 15249130 DOI: 10.1016/j.mce.2004.04.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2004] [Revised: 04/20/2004] [Accepted: 04/21/2004] [Indexed: 10/26/2022]
Abstract
During rapid development of the fetus, levels of high density lipoprotein (HDL) are elevated in pregnant women. The receptor for HDL, scavenger receptor class B type I (SR-BI), mediates selective cholesteryl ester uptake and is highly expressed in the human placenta. Because of the rapid growth of uterus during early pregnancy and differences in placentation between swine and humans, we hypothesized that SR-BI may be expressed in porcine endometrium to take up HDL cholesterol. The objectives of this study were to obtain the full coding region for porcine SR-BI, determine endometrial expression of SR-BI mRNA during the estrous cycle and early pregnancy, and map the gene. By iterative screening of a porcine expressed sequence tag library, we obtained the full coding region of SR-BI. Endometrial expression of SR-BI in White composite gilts (n = 3-4 each) was determined by Northern blotting on Days 10, 13, and 15 cyclic gilts and Days 10, 13, 15, 20, 30, and 40 pregnant gilts. In cyclic gilts, endometrial expression of SR-BI did not change between Days 10 and 13, but increased (P < 0.01) between Days 13 and 15. In pregnant gilts, endometrial expression of SR-BI increased (P < 0.01) between Days 10 and 13, remained elevated until Day 30, and decreased (P = 0.015) on Day 40. The SR-BI gene was mapped to 46.3 cM on chromosome 14. These results show that endometrial expression of SR-BI changes during the estrous cycle and early pregnancy, and suggest that SR-BI takes up HDL for endometrial development during early pregnancy.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- CD36 Antigens
- Cloning, Molecular
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Endometrium/metabolism
- Estrous Cycle/metabolism
- Female
- Gene Expression Regulation, Developmental
- Lipoproteins, HDL/metabolism
- Molecular Sequence Data
- Pregnancy
- Pregnancy, Animal/genetics
- Pregnancy, Animal/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Receptors, Scavenger
- Scavenger Receptors, Class B
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Swine
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Affiliation(s)
- J G Kim
- US Department of Agriculture, Agricultural Research Service, US Meat Animal Research Center, Clay Center, NE 68933, USA
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45
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Rhainds D, Brissette L. The role of scavenger receptor class B type I (SR-BI) in lipid trafficking. defining the rules for lipid traders. Int J Biochem Cell Biol 2004; 36:39-77. [PMID: 14592533 DOI: 10.1016/s1357-2725(03)00173-0] [Citation(s) in RCA: 158] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The scavenger receptor class B type I (SR-BI) is a 509-amino acid, 82 kDa glycoprotein, with two cytoplasmic C- and N-terminal domains separated by a large extracellular domain. The aim of this review is to define the role of SR-BI as a lipoprotein receptor responsible for selective uptake of cholesteryl esters (CE) from high density lipoprotein (HDL) and low density lipoprotein (LDL) and free cholesterol (FC) efflux to lipoprotein acceptors. These activities depend on lipoprotein binding to its extracellular domain and subsequent lipid exchange at the plasma membrane. CE selective uptake supplies cholesterol to liver and steroidogenic tissues, for biliary cholesterol secretion and steroid hormone synthesis. Genetically modified mice have confirmed SR-BI's major role in tissue cholesterol uptake and in reverse cholesterol transport, i.e. cholesterol turnover. Accordingly, cellular cholesterol level, estrogens and trophic hormones regulate SR-BI expression by both transcriptional and post-transcriptional mechanisms. Importantly, mouse SR-BI overexpression has both corrective and preventive effects on atherosclerosis. Human SR-BI has very similar tissue distribution, binding properties and lipid transfer activities compared to rodent SR-BI. However, human plasma has most of its cholesterol in LDL. Thus, there is considerable interest to develop anti-atherogenic strategies involving human SR-BI-mediated increases in reverse cholesterol transport through HDL and/or LDL.
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MESH Headings
- Amino Acid Sequence
- Animals
- Biological Transport, Active
- CD36 Antigens
- Cell Membrane/chemistry
- Cell Membrane/genetics
- Cell Membrane/metabolism
- Cell Membrane/physiology
- Humans
- Lipid Metabolism
- Lipoproteins/metabolism
- Models, Biological
- Promoter Regions, Genetic
- Protein Structure, Tertiary
- Receptors, Immunologic/chemistry
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Receptors, Immunologic/physiology
- Receptors, Scavenger
- Scavenger Receptors, Class B
- Tissue Distribution
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Affiliation(s)
- David Rhainds
- Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succ. Centre-Ville, Montreal, Que., Canada H3C 3P8.
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Mardones P, Rigotti A. Cellular mechanisms of vitamin E uptake: relevance in α-tocopherol metabolism and potential implications for disease. J Nutr Biochem 2004; 15:252-60. [PMID: 15135148 DOI: 10.1016/j.jnutbio.2004.02.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2003] [Indexed: 01/24/2023]
Abstract
alpha-Tocopherol is an essential micronutrient involved in various oxidative stress-related processes. Because of its hydrophobic nature, alpha-tocopherol is transported in plasma lipoproteins, and the pathways involved in its cellular uptake are closely related to the lipoprotein metabolism. alpha-Tocopherol transfer from plasma to cells can occur by different mechanisms such as uptake facilitated by lipid transfer proteins and lipases, receptor-mediated lipoprotein endocytosis, and selective lipid uptake. Here we discuss recent progress in understanding the physiological and pathophysiological relevance of these different pathways for cellular uptake of vitamin E in vivo. This review is mainly focused on the role of the scavenger receptor class B type I (SR-BI) on alpha-tocopherol metabolism and its potential implications for disease conditions.
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Affiliation(s)
- Pablo Mardones
- Departamento de Gastroenterología, Facultad de Medicina, Pontificia Universidad Católica, Marcoleta 367, Santiago, Chile
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Selva DM, Hirsch-Reinshagen V, Burgess B, Zhou S, Chan J, McIsaac S, Hayden MR, Hammond GL, Vogl AW, Wellington CL. The ATP-binding cassette transporter 1 mediates lipid efflux from Sertoli cells and influences male fertility. J Lipid Res 2004; 45:1040-50. [PMID: 15026428 DOI: 10.1194/jlr.m400007-jlr200] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The liver X receptor/retinoid X receptor (LXR/RXR)-regulated gene ABCA1 effluxes cellular cholesterol and phospholipid to apolipoprotein A1 (apoA1), which is the rate-limiting step in high-density lipoprotein synthesis. The RXR pathway plays a critical role in testicular lipid trafficking, and RXRbeta-deficient male mice are sterile and accumulate lipids in Sertoli cells. Here, we demonstrate that ABCA1 mRNA and protein are abundant in Sertoli cells, whereas germ cells express little ABCA1. LXR/RXR agonists stimulate ABCA1 expression in cultured Sertoli MSC1 and Leydig TM3 cell lines. However, Sertoli TM4 cells lack ABCA1, and TM4 cells or primary Sertoli cells cultured from ABCA1(-/-) mice both fail to efflux cholesterol to apoA1. Expression of exogenous ABCA1 restores apoA1-dependent cholesterol efflux in Sertoli TM4 cells. In vivo, ABCA1-deficient mice exhibit lipid accumulation in Sertoli cells and depletion of normal lipid droplets from Leydig cells by 2 months of age. By 6 months of age, intratesticular testosterone levels and sperm counts are significantly reduced in ABCA1(-/-) mice compared with wild-type (WT) controls. Finally, a 21% decrease (P = 0.01) in fertility was observed between ABCA1(-/-) males compared with WT controls across their reproductive lifespans. These results show that ABCA1 plays an important role in lipid transport in Sertoli cells and influences male fertility.
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Affiliation(s)
- David M Selva
- Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, BC, Canada
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Schmid KE, Davidson WS, Myatt L, Woollett LA. Transport of cholesterol across a BeWo cell monolayer: implications for net transport of sterol from maternal to fetal circulation. J Lipid Res 2003; 44:1909-18. [PMID: 12897187 DOI: 10.1194/jlr.m300126-jlr200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The placental transport of various compounds, such as glucose and fatty acids, has been well studied. However, the transport of cholesterol, a sterol essential for proper fetal development, remains undefined in the placenta. Therefore, the purpose of these studies was to examine the transport of cholesterol across a placental monolayer and its uptake by various cholesterol acceptors. BeWo cells, which originated from a human choriocarcinoma, were grown on transwells for 3 days to form a confluent monolayer. The apical side of the cells was radiolabeled with either free cholesterol or LDL cholesteryl ester. After 24 h, the radiolabel was removed and cholesterol acceptors were added to the basolateral chamber. Cholesterol was found to be taken up by the apical surface of the placental monolayer, transported to the basolateral surface of the cell, and effluxed to fetal human serum, fetal HDL, or phospholipid vesicles, but not to apolipoprotein A-I. In addition, increasing the cellular cholesterol concentration further increased the amount of cholesterol transported to the basolateral acceptors. These are the first studies to demonstrate the movement of cholesterol across a placental cell from the maternal circulation (apical side) to the fetal circulation (basolateral side).
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Affiliation(s)
- Kara E Schmid
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
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Tietge UJF, Maugeais C, Cain W, Rader DJ. Acute inflammation increases selective uptake of HDL cholesteryl esters into adrenals of mice overexpressing human sPLA2. Am J Physiol Endocrinol Metab 2003; 285:E403-11. [PMID: 12637261 DOI: 10.1152/ajpendo.00576.2002] [Citation(s) in RCA: 28] [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: 01/12/2023]
Abstract
The acute-phase protein secretory phospholipase A2 (sPLA2) influences the metabolism of high-density lipoproteins (HDL). The adrenals are known to utilize HDL cholesterol as a source of sterols. The aim of the present study was to test the hypothesis that sPLA2 enhances the selective uptake of HDL into the adrenals in response to acute inflammation as a possible physiological role for the sPLA2-HDL interaction. Human sPLA2-transgenic mice, in which sPLA2 expression is upregulated by inflammatory stimuli, were used. Ten hours after induction of the acute-phase response (APR) by injection of bacterial lipopolysaccharide (LPS), plasma levels of HDL cholesterol decreased significantly in sPLA2-transgenic mice (-18%, P < 0.05) but remained unchanged in wild-type mice. The fractional catabolic rates of both 125I-labeled tyraminecellobiose (TC)-HDL and [3H]cholesteryl ether increased significantly in the sPLA2-transgenic mice after induction of the APR (0.18 +/- 0.01 vs. 0.21 +/- 0.01 pool/h, P < 0.05, and 0.31 +/- 0.02 vs. 0.42 +/- 0.05 pool/h, P < 0.05, respectively) but remained unchanged in the wild-type mice (0.10 +/- 0.01 vs. 0.22 +/- 0.02 pool/h, respectively). After induction of the APR, in both groups HDL holoparticle uptake by the liver was increased (P < 0.001). sPLA2-transgenic mice had 2.4-fold higher selective uptake into the adrenals after induction of the APR than wild-type mice (156 +/- 6 vs. 65 +/- 5%/ micro g tissue protein, P < 0.001). In summary, upregulation of sPLA2 expression during the APR specifically increases the selective uptake of HDL cholesteryl ester into the adrenals. These data suggest a novel metabolic role for sPLA2: modification of HDL during the APR to promote increased adrenal uptake of HDL cholesteryl ester to serve as source for steroid hormone synthesis.
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Affiliation(s)
- Uwe J F Tietge
- Univ. of Pennsylvania Medical Center, 654 BRB II/III, 421 Curie Blvd., Philadelphia, PA 19104-6160, USA.
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Rigotti A, Miettinen HE, Krieger M. The role of the high-density lipoprotein receptor SR-BI in the lipid metabolism of endocrine and other tissues. Endocr Rev 2003; 24:357-87. [PMID: 12788804 DOI: 10.1210/er.2001-0037] [Citation(s) in RCA: 313] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Because cholesterol is a precursor for the synthesis of steroid hormones, steroidogenic tissues have evolved multiple pathways to ensure adequate supplies of cholesterol. These include synthesis, storage as cholesteryl esters, and import from lipoproteins. In addition to endocytosis via members of the low-density lipoprotein receptor superfamily, steroidogenic cells acquire cholesterol from lipoproteins by selective lipid uptake. This pathway, which does not involve lysosomal degradation of the lipoprotein, is mediated by the scavenger receptor class B type I (SR-BI). SR-BI is highly expressed in steroidogenic cells, where its expression is regulated by various trophic hormones, as well as in the liver. Studies of genetically manipulated strains of mice have established that SR-BI plays a key role in regulating lipoprotein metabolism and cholesterol transport to steroidogenic tissues and to the liver for biliary secretion. In addition, analysis of SR-BI-deficient mice has shown that SR-BI expression is important for alpha-tocopherol and nitric oxide metabolism, as well as normal red blood cell maturation and female fertility. These mouse models have also revealed that SR-BI can protect against atherosclerosis. If SR-BI plays similar physiological and pathophysiological roles in humans, it may be an attractive target for therapeutic intervention in cardiovascular and reproductive diseases.
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Affiliation(s)
- Attilio Rigotti
- Departamento de Gastroenterología, Facultad de Medicina, Pontificia Universidad Católica, Santiago, Chile
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