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Parsons TK, Pratt RN, Tang L, Wu Y. An active and selective molecular mechanism mediating the uptake of sex steroids by prostate cancer cells. Mol Cell Endocrinol 2018; 477:121-131. [PMID: 29928927 DOI: 10.1016/j.mce.2018.06.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/31/2018] [Accepted: 06/16/2018] [Indexed: 12/21/2022]
Abstract
Steroid hormones play important roles in normal physiological functions and diseases. Sex steroids hormones are important in the biology and treatment of sex hormone-related cancer such as prostate cancer and breast cancer. Cells may take up steroids using multiple mechanisms. The conventionally accepted hypothesis that steroids cross cell membrane through passive diffusion has not been tested rigorously. Experimental data suggested that cells may take up sex steroid using an active uptake mechanism. 3H-testosterone uptake by prostate cancer cells showed typical transporter-mediated uptake kinetic. Cells retained testosterone taken up from the medium. The uptake of testosterone was selective for certain steroid hormones but not others. Data also indicated that the active and selective uptake mechanism resided in cholesterol-rich membrane domains, and may involve ATP and membrane transporters. In summary, the present study provided strong evidence to support the existence of an active and selective molecular mechanism for sex steroid uptake.
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Affiliation(s)
- Todd K Parsons
- Department of Urology, Roswell Park Comprehensive Cancer Center, Elm and Carlton Streets, Buffalo, NY, 14263, USA
| | - Rachel N Pratt
- Department of Cancer Prevention and Control, Roswell Park Comprehensive Cancer Center, Elm and Carlton Streets, Buffalo, NY, 14263, USA
| | - Li Tang
- Department of Cancer Prevention and Control, Roswell Park Comprehensive Cancer Center, Elm and Carlton Streets, Buffalo, NY, 14263, USA
| | - Yue Wu
- Department of Urology, Roswell Park Comprehensive Cancer Center, Elm and Carlton Streets, Buffalo, NY, 14263, USA.
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2
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Toledo A, Huang Z, Coleman JL, London E, Benach JL. Lipid rafts can form in the inner and outer membranes of Borrelia burgdorferi and have different properties and associated proteins. Mol Microbiol 2018; 108:63-76. [PMID: 29377398 DOI: 10.1111/mmi.13914] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 01/03/2018] [Accepted: 01/21/2018] [Indexed: 01/23/2023]
Abstract
Lipid rafts are microdomains present in the membrane of eukaryotic organisms and bacterial pathogens. They are characterized by having tightly packed lipids and a subset of specific proteins. Lipid rafts are associated with a variety of important biological processes including signaling and lateral sorting of proteins. To determine whether lipid rafts exist in the inner membrane of Borrelia burgdorferi, we separated the inner and outer membranes and analyzed the lipid constituents present in each membrane fraction. We found that both the inner and outer membranes have cholesterol and cholesterol glycolipids. Fluorescence anisotropy and FRET showed that lipids from both membranes can form rafts but have different abilities to do so. The analysis of the biochemically defined proteome of lipid rafts from the inner membrane revealed a diverse set of proteins, different from those associated with the outer membrane, with functions in protein trafficking, chemotaxis and signaling.
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Affiliation(s)
- Alvaro Toledo
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, USA
| | - Zhen Huang
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA
| | - James L Coleman
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, USA
| | - Erwin London
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA
| | - Jorge L Benach
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, USA
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3
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Morel E, Ghezzal S, Lucchi G, Truntzer C, Pais de Barros JP, Simon-Plas F, Demignot S, Mineo C, Shaul PW, Leturque A, Rousset M, Carrière V. Cholesterol trafficking and raft-like membrane domain composition mediate scavenger receptor class B type 1-dependent lipid sensing in intestinal epithelial cells. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1863:199-211. [PMID: 29196159 DOI: 10.1016/j.bbalip.2017.11.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 11/13/2017] [Accepted: 11/27/2017] [Indexed: 02/02/2023]
Abstract
Scavenger receptor Class B type 1 (SR-B1) is a lipid transporter and sensor. In intestinal epithelial cells, SR-B1-dependent lipid sensing is associated with SR-B1 recruitment in raft-like/ detergent-resistant membrane domains and interaction of its C-terminal transmembrane domain with plasma membrane cholesterol. To clarify the initiating events occurring during lipid sensing by SR-B1, we analyzed cholesterol trafficking and raft-like domain composition in intestinal epithelial cells expressing wild-type SR-B1 or the mutated form SR-B1-Q445A, defective in membrane cholesterol binding and signal initiation. These features of SR-B1 were found to influence both apical cholesterol efflux and intracellular cholesterol trafficking from plasma membrane to lipid droplets, and the lipid composition of raft-like domains. Lipidomic analysis revealed likely participation of d18:0/16:0 sphingomyelin and 16:0/0:0 lysophosphatidylethanolamine in lipid sensing by SR-B1. Proteomic analysis identified proteins, whose abundance changed in raft-like domains during lipid sensing, and these included molecules linked to lipid raft dynamics and signal transduction. These findings provide new insights into the role of SR-B1 in cellular cholesterol homeostasis and suggest molecular links between SR-B1-dependent lipid sensing and cell cholesterol and lipid droplet dynamics.
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Affiliation(s)
- Etienne Morel
- Centre de Recherche des Cordeliers, INSERM, UMPC Université Paris 6, Université Paris Descartes Paris 5, CNRS, F-75006 Paris, France
| | - Sara Ghezzal
- Centre de Recherche des Cordeliers, INSERM, UMPC Université Paris 6, Université Paris Descartes Paris 5, CNRS, F-75006 Paris, France
| | - Géraldine Lucchi
- Clinical Innovation Proteomic Platform CLIPP, Université Bourgogne Franche-Comté, F-21000 Dijon, France
| | - Caroline Truntzer
- Clinical Innovation Proteomic Platform CLIPP, Université Bourgogne Franche-Comté, F-21000 Dijon, France
| | - Jean-Paul Pais de Barros
- Plateforme de Lipidomique, INSERM UMR1231, Université de Bourgogne Franche Comté, F-21000 Dijon, France
| | - Françoise Simon-Plas
- Agroécologie, AgroSup Dijon, CNRS, INRA, Université Bourgogne Franche-Comté, F-21000 Dijon, France
| | - Sylvie Demignot
- Centre de Recherche des Cordeliers, INSERM, UMPC Université Paris 6, Université Paris Descartes Paris 5, CNRS, F-75006 Paris, France; EPHE, PSL Research University, F-75006 Paris, France
| | - Chieko Mineo
- Center for Pulmonary and Vascular Biology, Department of Pediatrics, University of Texas, Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Philip W Shaul
- Center for Pulmonary and Vascular Biology, Department of Pediatrics, University of Texas, Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Armelle Leturque
- Centre de Recherche des Cordeliers, INSERM, UMPC Université Paris 6, Université Paris Descartes Paris 5, CNRS, F-75006 Paris, France
| | - Monique Rousset
- Centre de Recherche des Cordeliers, INSERM, UMPC Université Paris 6, Université Paris Descartes Paris 5, CNRS, F-75006 Paris, France
| | - Véronique Carrière
- Centre de Recherche des Cordeliers, INSERM, UMPC Université Paris 6, Université Paris Descartes Paris 5, CNRS, F-75006 Paris, France.
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4
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Gaibelet G, Tercé F, Allart S, Lebrun C, Collet X, Jamin N, Orlowski S. Fluorescent probes for detecting cholesterol-rich ordered membrane microdomains: entangled relationships between structural analogies in the membrane and functional homologies in the cell. AIMS Biophysics 2017. [DOI: 10.3934/biophy.2017.1.121] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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Nakano T, Inoue I, Takenaka Y, Ono H, Katayama S, Awata T, Murakoshi T. Ezetimibe Promotes Brush Border Membrane-to-Lumen Cholesterol Efflux in the Small Intestine. PLoS One 2016; 11:e0152207. [PMID: 27023132 PMCID: PMC4811413 DOI: 10.1371/journal.pone.0152207] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 03/10/2016] [Indexed: 11/19/2022] Open
Abstract
Ezetimibe inhibits Niemann-Pick C1-like 1 (NPC1L1), an apical membrane cholesterol transporter of enterocytes, thereby reduces intestinal cholesterol absorption. This treatment also increases extrahepatic reverse cholesterol transport via an undefined mechanism. To explore this, we employed a trans-intestinal cholesterol efflux (TICE) assay, which directly detects circulation-to-intestinal lumen 3H-cholesterol transit in a cannulated jejunal segment, and found an increase of TICE by 45%. To examine whether such increase in efflux occurs at the intestinal brush border membrane(BBM)-level, we performed luminal perfusion assays, similar to TICE but the jejunal wall was labelled with orally-given 3H-cholesterol, and determined elevated BBM-to-lumen cholesterol efflux by 3.5-fold with ezetimibe. Such increased efflux probably promotes circulation-to-lumen cholesterol transit eventually; thus increases TICE. Next, we wondered how inhibition of NPC1L1, an influx transporter, resulted in increased efflux. When we traced orally-given 3H-cholesterol in mice, we found that lumen-to-BBM 3H-cholesterol transit was rapid and less sensitive to ezetimibe treatment. Comparison of the efflux and fractional cholesterol absorption revealed an inverse correlation, indicating the efflux as an opposite-regulatory factor for cholesterol absorption efficiency and counteracting to the naturally-occurring rapid cholesterol influx to the BBM. These suggest that the ezetimibe-stimulated increased efflux is crucial in reducing cholesterol absorption. Ezetimibe-induced increase in cholesterol efflux was approximately 2.5-fold greater in mice having endogenous ATP-binding cassette G5/G8 heterodimer, the major sterol efflux transporter of enterocytes, than the knockout counterparts, suggesting that the heterodimer confers additional rapid BBM-to-lumen cholesterol efflux in response to NPC1L1 inhibition. The observed framework for intestinal cholesterol fluxes may provide ways to modulate the flux to dispose of endogenous cholesterol efficiently for therapeutic purposes.
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Affiliation(s)
- Takanari Nakano
- Department of Biochemistry, Faculty of Medicine, Saitama Medical University, Iruma-gun, Saitama, Japan
- * E-mail:
| | - Ikuo Inoue
- Department of Diabetes and Endocrinology, Faculty of Medicine, Saitama Medical University, Iruma-gun, Saitama, Japan
| | - Yasuhiro Takenaka
- Department of Diabetes and Endocrinology, Faculty of Medicine, Saitama Medical University, Iruma-gun, Saitama, Japan
| | - Hiraku Ono
- Department of Diabetes and Endocrinology, Faculty of Medicine, Saitama Medical University, Iruma-gun, Saitama, Japan
| | - Shigehiro Katayama
- Department of Diabetes and Endocrinology, Faculty of Medicine, Saitama Medical University, Iruma-gun, Saitama, Japan
| | - Takuya Awata
- Department of Diabetes, Endocrinology and Metabolism, International University of Health and Welfare Hospital, Nasushiobara-shi, Tochigi, Japan
| | - Takayuki Murakoshi
- Department of Biochemistry, Faculty of Medicine, Saitama Medical University, Iruma-gun, Saitama, Japan
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Ontsouka EC, Huang X, Stieger B, Albrecht C. Characteristics and functional relevance of apolipoprotein-A1 and cholesterol binding in mammary gland tissues and epithelial cells. PLoS One 2013; 8:e70407. [PMID: 23936200 PMCID: PMC3729845 DOI: 10.1371/journal.pone.0070407] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 06/18/2013] [Indexed: 11/19/2022] Open
Abstract
Cholesterol in milk is derived from the circulating blood through a complex transport process involving the mammary alveolar epithelium. Details of the mechanisms involved in this transfer are unclear. Apolipoprotein-AI (apoA-I) is an acceptor of cellular cholesterol effluxed by the ATP-binding cassette (ABC) transporter A1 (ABCA1). We aimed to 1) determine the binding characteristics of (125)I-apoA-I and (3)H-cholesterol to enriched plasma membrane vesicles (EPM) isolated from lactating and non-lactating bovine mammary glands (MG), 2) optimize the components of an in vitro model describing cellular (3)H-cholesterol efflux in primary bovine mammary epithelial cells (MeBo), and 3) assess the vectorial cholesterol transport in MeBo using Transwell(®) plates. The amounts of isolated EPM and the maximal binding capacity of (125)I-apoA-I to EPM differed depending on the MG's physiological state, while the kinetics of (3)H-cholesterol and (125)I-apoA-I binding were similar. (3)H-cholesterol incorporated maximally to EPM after 25±9 min. The time to achieve the half-maximum binding of (125)I-apoA-I at equilibrium was 3.3±0.6 min. The dissociation constant (KD) of (125)I-apoA-I ranged between 40-74 nmol/L. Cholesterol loading to EPM increased both cholesterol content and (125)I-apoA-I binding. The ABCA1 inhibitor Probucol displaced (125)I-apoA-I binding to EPM and reduced (3)H-cholesterol efflux in MeBo. Time-dependent (3)H-cholesterol uptake and efflux showed inverse patterns. The defined binding characteristics of cholesterol and apoA-I served to establish an efficient and significantly shorter cholesterol efflux protocol that had been used in MeBo. The application of this protocol in Transwell(®) plates with the upper chamber mimicking the apical (milk-facing) and the bottom chamber corresponding to the basolateral (blood-facing) side of cells showed that the degree of (3)H-cholesterol efflux in MeBo differed significantly between the apical and basolateral aspects. Our findings support the importance of the apoA-I/ABCA1 pathway in MG cholesterol transport and suggest its role in influencing milk composition and directing cholesterol back into the bloodstream.
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Affiliation(s)
- Edgar Corneille Ontsouka
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Bern, Switzerland
- Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland
| | - Xiao Huang
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Bern, Switzerland
- Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland
| | - Bruno Stieger
- Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Zürich, Switzerland
| | - Christiane Albrecht
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Bern, Switzerland
- Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland
- * E-mail:
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8
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Wang LJ, Song BL. Niemann-Pick C1-Like 1 and cholesterol uptake. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:964-72. [PMID: 22480541 DOI: 10.1016/j.bbalip.2012.03.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Revised: 03/09/2012] [Accepted: 03/12/2012] [Indexed: 01/27/2023]
Abstract
Niemann-Pick C1-Like 1 (NPC1L1) is a polytopic transmembrane protein responsible for dietary cholesterol and biliary cholesterol absorption. Consistent with its functions, NPC1L1 distributes on the brush border membrane of enterocytes and the canalicular membrane of hepatocytes in humans. As the molecular target of ezetimibe, a hypocholesterolemic drug, its physiological and pathological significance has been recognized and intensively studied for years. Recently, plenty of new findings reveal the molecular mechanism of NPC1L1's role in cholesterol uptake, which may provide new insights on our understanding of cholesterol absorption. In this review, we summarized recent progress in these studies and proposed a working model, hoping to provide new perspectives on the regulation of cholesterol transport and metabolism.
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D'arrigo J. Aspects of Future R&D Regarding Targeted Lipid Nanoemulsions. Stable Nanoemulsions: Self-Assembly in Nature and Nanomedicine. Elsevier; 2011. pp. 333-42. [DOI: 10.1016/b978-0-444-53798-0.00029-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Klappe K, Hummel I, Hoekstra D, Kok JW. Lipid dependence of ABC transporter localization and function. Chem Phys Lipids 2009; 161:57-64. [PMID: 19651114 DOI: 10.1016/j.chemphyslip.2009.07.004] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 06/24/2009] [Accepted: 07/24/2009] [Indexed: 02/06/2023]
Abstract
Lipid rafts have been implicated in many cellular functions, including protein and lipid transport and signal transduction. ATP-binding cassette (ABC) transporters have also been localized in these membrane domains. In this review the evidence for this specific localization will be evaluated and discussed in terms of relevance to ABC transporter function. We will focus on three ABC transporters of the A, B and C subfamily, respectively. Two of these transporters are relevant to multidrug resistance in tumor cells (Pgp/ABCB1 and MRP1/ABCC1), while the third (ABCA1) is extensively studied in relation to the reverse cholesterol pathway and cellular cholesterol homeostasis. We will attempt to derive a generalized model of lipid rafts to which they associate based on the use of various different lipid raft isolation procedures. In the context of lipid rafts, modulation of ABC transporter localization and function by two relevant lipid classes, i.e. sphingolipids and cholesterol, will be discussed.
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Affiliation(s)
- Karin Klappe
- Department of Cell Biology, Section Membrane Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
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Hegedűs C, Szakács G, Homolya L, Orbán TI, Telbisz Á, Jani M, Sarkadi B. Ins and outs of the ABCG2 multidrug transporter: an update on in vitro functional assays. Adv Drug Deliv Rev 2009; 61:47-56. [PMID: 19135105 DOI: 10.1016/j.addr.2008.09.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Accepted: 09/03/2008] [Indexed: 02/07/2023]
Abstract
The major aim of this chapter is to provide a critical overview of the in vitro methods available for studying the function of the ABCG2 multidrug transporter protein. When describing the most applicable assay systems, in each case we present a short overview relevant to ABC multidrug transporters in general, and then we concentrate on the tools applicable to analysis of substrate-drug interactions, the effects of potential activators and inhibitors, and the role of polymorphisms of the ABCG2 transporter. Throughout this chapter we focus on recently developed assay systems, which may provide new possibilities for analyzing the pharmacological aspects of this medically important protein.
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Béaslas O, Cueille C, Delers F, Chateau D, Chambaz J, Rousset M, Carrière V. Sensing of dietary lipids by enterocytes: a new role for SR-BI/CLA-1. PLoS One 2009; 4:e4278. [PMID: 19169357 PMCID: PMC2627924 DOI: 10.1371/journal.pone.0004278] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Accepted: 12/17/2008] [Indexed: 11/23/2022] Open
Abstract
Background The intestine is responsible for absorbing dietary lipids and delivering them to the organism as triglyceride-rich lipoproteins (TRL). It is important to determine how this process is regulated in enterocytes, the absorptive cells of the intestine, as prolonged postprandial hypertriglyceridemia is a known risk factor for atherosclerosis. During the postprandial period, dietary lipids, mostly triglycerides (TG) hydrolyzed by pancreatic enzymes, are combined with bile products and reach the apical membrane of enterocytes as postprandial micelles (PPM). Our aim was to determine whether these micelles induce, in enterocytes, specific early cell signaling events that could control the processes leading to TRL secretion. Methodology/Principal Findings The effects of supplying PPM to the apex of Caco-2/TC7 enterocytes were analyzed. Micelles devoid of TG hydrolysis products, like those present in the intestinal lumen in the interprandial period, were used as controls. The apical delivery of PPM specifically induced a number of cellular events that are not induced by interprandial micelles. These early events included the trafficking of apolipoprotein B, a structural component of TRL, from apical towards secretory domains, and the rapid, dose-dependent activation of ERK and p38MAPK. PPM supply induced the scavenger receptor SR-BI/CLA-1 to cluster at the apical brush border membrane and to move from non-raft to raft domains. Competition, inhibition or knockdown of SR-BI/CLA-1 impaired the PPM-dependent apoB trafficking and ERK activation. Conclusions/Significance These results are the first evidence that enterocytes specifically sense postprandial dietary lipid-containing micelles. SR-BI/CLA-1 is involved in this process and could be a target for further study with a view to modifying intestinal TRL secretion early in the control pathway.
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Affiliation(s)
- Olivier Béaslas
- Université Pierre et Marie Curie - Paris 6, UMR S 872, Les Cordeliers, Paris, France
- INSERM, U 872, Paris, France
- Université Paris Descartes, UMR S 872, Paris, France
| | - Carine Cueille
- Université Pierre et Marie Curie - Paris 6, UMR S 872, Les Cordeliers, Paris, France
- INSERM, U 872, Paris, France
- Université Paris Descartes, UMR S 872, Paris, France
| | - François Delers
- Université Pierre et Marie Curie - Paris 6, UMR S 872, Les Cordeliers, Paris, France
- INSERM, U 872, Paris, France
- Université Paris Descartes, UMR S 872, Paris, France
| | - Danielle Chateau
- Université Pierre et Marie Curie - Paris 6, UMR S 872, Les Cordeliers, Paris, France
- INSERM, U 872, Paris, France
- Université Paris Descartes, UMR S 872, Paris, France
| | - Jean Chambaz
- Université Pierre et Marie Curie - Paris 6, UMR S 872, Les Cordeliers, Paris, France
- INSERM, U 872, Paris, France
- Université Paris Descartes, UMR S 872, Paris, France
| | - Monique Rousset
- Université Pierre et Marie Curie - Paris 6, UMR S 872, Les Cordeliers, Paris, France
- INSERM, U 872, Paris, France
- Université Paris Descartes, UMR S 872, Paris, France
| | - Véronique Carrière
- Université Pierre et Marie Curie - Paris 6, UMR S 872, Les Cordeliers, Paris, France
- INSERM, U 872, Paris, France
- Université Paris Descartes, UMR S 872, Paris, France
- * E-mail:
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Moussa M, Landrier JF, Reboul E, Ghiringhelli O, Coméra C, Collet X, Fröhlich K, Böhm V, Borel P. Lycopene absorption in human intestinal cells and in mice involves scavenger receptor class B type I but not Niemann-Pick C1-like 1. J Nutr 2008; 138:1432-6. [PMID: 18641187 DOI: 10.1093/jn/138.8.1432] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Cholesterol membrane transporters scavenger receptor class B type I (SR-BI) and (cluster determinant 36) are involved in intestinal uptake of lutein and beta-carotene, 2 of the 3 main carotenoids of the human diet. The aim of this work was therefore to determine whether SR-BI and NPC1L1 (Niemann-Pick C1-like 1), another cholesterol transporter, are implicated in absorption of lycopene, the 3rd main carotenoid of the human diet. Anti-human SR-BI antibody and block lipid transport 1 (BLT1) (a chemical inhibitor of lipid transport by SR-BI) impaired up to 60% (all-E) and (5Z)-lycopene uptake (P < 0.05) by Caco-2 cell monolayers, which were used as a model of human intestinal epithelium. The involvement of SR-BI in lycopene absorption in vivo was then verified by comparing plasma lycopene concentrations in wild-type and SR-BI transgenic mice that were fed a diet enriched with 0.25 g/kg (all-E)-lycopene for 1 mo. Plasma lycopene concentrations were approximately 10-fold higher (P < 0.001) in mice overexpressing SR-BI in the intestine than in wild-type mice, confirming the involvement of SR-BI in lycopene absorption. Further experiments showed that (all-E)-lycopene did not affect SR-BI mRNA levels in Caco-2 cells or mouse intestine. In contrast to SR-BI, neither anti-human NPC1L1 antibody nor ezetimibe, used as inhibitors of lycopene uptake via NPC1L1, significantly impaired (all-E) or (5Z)-lycopene uptake by Caco-2 monolayers. Thus, the present data show that lycopene absorption is, at least in part, mediated by SR-BI but not by NPC1L1.
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Affiliation(s)
- Myriam Moussa
- Institut National de la Recherche Agronomique, UMR1260 Nutriments Lipidiques et Prévention des Maladies Métaboliques, F-13385 Marseille, France
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Duggan J, Jamal G, Tilley M, Davis B, McKenzie G, Vere K, Somekh MG, O'Shea P, Harris H. Functional imaging of microdomains in cell membranes. Eur Biophys J 2008; 37:1279-89. [PMID: 18654769 DOI: 10.1007/s00249-008-0349-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 05/28/2008] [Accepted: 06/04/2008] [Indexed: 10/21/2022]
Abstract
The presence of microdomains or rafts within cell membranes is a topic of intense study and debate. The role of these structures in cell physiology, however, is also not yet fully understood with many outstanding problems. This problem is partly based on the small size of raft structures that presents significant problems to their in vivo study, i.e., within live cell membranes. But the structure and dynamics as well as the factors that control the assembly and disassembly of rafts are also of major interest. In this review we outline some of the problems that the study of rafts in cell membranes present as well as describing some views of what are considered the generalised functions of membrane rafts. We point to the possibility that there may be several different 'types' of membrane raft in cell membranes and consider the factors that affect raft assembly and disassembly, particularly, as some researchers suggest that the lifetimes of rafts in cell membranes may be sub-second. We attempt to review some of the methods that offer the ability to interrogate rafts directly as well as describing factors that appear to affect their functionality. The former include both near-field and far-field optical approaches as well as scanning probe techniques. Some of the advantages and disadvantages of these techniques are outlined. Finally, we describe our own views of raft functionality and properties, particularly, concerning the membrane dipole potential, and describe briefly some of the imaging strategies we have developed for their study.
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Affiliation(s)
- James Duggan
- Cell Biophysics Group, School of Biology, University of Nottingham, Nottingham, NG7 2UH, UK
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Weinglass AB, Köhler MG, Nketiah EO, Liu J, Schmalhofer W, Thomas A, Williams B, Beers L, Smith L, Hafey M, Bleasby K, Leone J, Tang YS, Braun M, Ujjainwalla F, McCann ME, Kaczorowski GJ, Garcia ML. Madin-Darby canine kidney II cells: a pharmacologically validated system for NPC1L1-mediated cholesterol uptake. Mol Pharmacol 2008; 73:1072-84. [PMID: 18187582 DOI: 10.1124/mol.107.043844] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Absorption of dietary cholesterol in the proximal region of the intestine is mediated by Niemann-Pick C1-like protein (NPC1L1) and is sensitive to the cholesterol absorption inhibitor ezetimibe (EZE). Although a correlation exists between EZE binding to NPC1L1 in vitro and efficacy in vivo, the precise nature of interaction(s) between NPC1L1, EZE, and cholesterol remain unclear. Here, we analyze the direct relationship between EZE analog binding to NPC1L1 and its influence on cholesterol influx in a novel in vitro system. Using the EZE analog [(3)H]AS, an assay that quantitatively measures the expression of NPC1L1 on the cell surface has been developed. It is noteworthy that whereas two cell lines (CaCo-2 and HepG2) commonly used for studying NPC1L1-dependent processes express almost undetectable levels of NPC1L1 at the cell surface, polarized Madin-Darby canine kidney (MDCKII) cells endogenously express 4 x 10(5) [(3)H]AS sites/cell under basal conditions. Depleting endogenous cholesterol with the HMG CoA reductase inhibitor lovastatin leads to a 2-fold increase in the surface expression of NPC1L1, supporting the contention that MDCKII cells respond to changes in cholesterol homeostasis by up-regulating a pathway for cholesterol influx. However, a significant increase in surface expression levels of NPC1L1 is necessary to characterize a pharmacologically sensitive, EZE-dependent pathway of cholesterol uptake in these cells. Remarkably, the affinity of EZE analogs for binding to NPC1L1 is almost identical to the IC(50) blocking cholesterol flux through NPC1L1 in MDCKII cells. From a mechanistic standpoint, these observations support the contention that EZE analogs and cholesterol share the same/overlapping binding site(s) or are tightly coupled through allosteric interactions.
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Affiliation(s)
- Adam B Weinglass
- Department of Ion Channels, Merck Research Laboratories, P.O. Box 2000, Rahway, NJ 07065, USA.
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