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Fung KYY, Ho TWW, Xu Z, Neculai D, Beauchemin CAA, Lee WL, Fairn GD. Apolipoprotein A1 and high-density lipoprotein limit low-density lipoprotein transcytosis by binding SR-B1. J Lipid Res 2024; 65:100530. [PMID: 38479648 PMCID: PMC11004410 DOI: 10.1016/j.jlr.2024.100530] [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: 09/06/2022] [Revised: 02/27/2024] [Accepted: 02/29/2024] [Indexed: 04/09/2024] Open
Abstract
Atherosclerosis results from the deposition and oxidation of LDL and immune cell infiltration in the sub-arterial space leading to arterial occlusion. Studies have shown that transcytosis transports circulating LDL across endothelial cells lining blood vessels. LDL transcytosis is initiated by binding to either scavenger receptor B1 (SR-B1) or activin A receptor-like kinase 1 on the apical side of endothelial cells leading to its transit and release on the basolateral side. HDL is thought to partly protect individuals from atherosclerosis due to its ability to remove excess cholesterol and act as an antioxidant. Apolipoprotein A1 (APOA1), an HDL constituent, can bind to SR-B1, raising the possibility that APOA1/HDL can compete with LDL for SR-B1 binding, thereby limiting LDL deposition in the sub-arterial space. To examine this possibility, we used in vitro approaches to quantify the internalization and transcytosis of fluorescent LDL in coronary endothelial cells. Using microscale thermophoresis and affinity capture, we find that SR-B1 and APOA1 interact and that binding is enhanced when using the cardioprotective variant of APOA1 termed Milano (APOA1-Milano). In male mice, transiently increasing the levels of HDL reduced the acute deposition of fluorescently labeled LDL in the atheroprone inner curvature of the aorta. Reduced LDL deposition was also observed when increasing circulating wild-type APOA1 or the APOA1-Milano variant, with a more robust inhibition from the APOA1-Milano. The results suggest that HDL may limit SR-B1-mediated LDL transcytosis and deposition, adding to the mechanisms by which it can act as an atheroprotective particle.
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Affiliation(s)
- Karen Y Y Fung
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada
| | - Tse Wing Winnie Ho
- Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Zizhen Xu
- Department of Cell Biology, and Department of Pathology Sir Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Dante Neculai
- Department of Cell Biology, and Department of Pathology Sir Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Catherine A A Beauchemin
- Department of Physics, Toronto Metropolitan University, Toronto, Ontario, Canada; Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) program, RIKEN, Wako, Saitama, Japan
| | - Warren L Lee
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada.
| | - Gregory D Fairn
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.
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2
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Caron NS, Aly AEE, Findlay Black H, Martin DDO, Schmidt ME, Ko S, Anderson C, Harvey EM, Casal LL, Anderson LM, Rahavi SMR, Reid GSD, Oda MN, Stanimirovic D, Abulrob A, McBride JL, Leavitt BR, Hayden MR. Systemic delivery of mutant huntingtin lowering antisense oligonucleotides to the brain using apolipoprotein A-I nanodisks for Huntington disease. J Control Release 2024; 367:27-44. [PMID: 38215984 DOI: 10.1016/j.jconrel.2024.01.011] [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: 08/13/2023] [Revised: 12/09/2023] [Accepted: 01/09/2024] [Indexed: 01/14/2024]
Abstract
Efficient delivery of therapeutics to the central nervous system (CNS) remains a major challenge for the treatment of neurological diseases. Huntington disease (HD) is a dominantly inherited neurodegenerative disorder caused by a CAG trinucleotide expansion mutation in the HTT gene which codes for a toxic mutant huntingtin (mHTT) protein. Pharmacological reduction of mHTT in the CNS using antisense oligonucleotides (ASO) ameliorates HD-like phenotypes in rodent models of HD, with such therapies being investigated in clinical trials for HD. In this study, we report the optimization of apolipoprotein A-I nanodisks (apoA-I NDs) as vehicles for delivery of a HTT-targeted ASO (HTT ASO) to the brain and peripheral organs for HD. We demonstrate that apoA-I wild type (WT) and the apoA-I K133C mutant incubated with a synthetic lipid, 1,2-dimyristoyl-sn-glycero-3-phosphocholine, can self-assemble into monodisperse discoidal particles with diameters <20 nm that transmigrate across an in vitro blood-brain barrier model of HD. We demonstrate that apoA-I NDs are well tolerated in vivo, and that apoA-I K133C NDs show enhanced distribution to the CNS and peripheral organs compared to apoA-I WT NDs following systemic administration. ApoA-I K133C conjugated with HTT ASO forms NDs (HTT ASO NDs) that induce significant mHTT lowering in the liver, skeletal muscle and heart as well as in the brain when delivered intravenously in the BACHD mouse model of HD. Furthermore, HTT ASO NDs increase the magnitude of mHTT lowering in the striatum and cortex compared to HTT ASO alone following intracerebroventricular administration. These findings demonstrate the potential utility of apoA-I NDs as biocompatible vehicles for enhancing delivery of mutant HTT lowering ASOs to the CNS and peripheral organs for HD.
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Affiliation(s)
- Nicholas S Caron
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Amirah E-E Aly
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hailey Findlay Black
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Dale D O Martin
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada; Department of Biology, University of Waterloo, Ontario, Canada
| | - Mandi E Schmidt
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada
| | - Seunghyun Ko
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Christine Anderson
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Emily M Harvey
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Lorenzo L Casal
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Lisa M Anderson
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Seyed M R Rahavi
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gregor S D Reid
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Danica Stanimirovic
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Abedelnasser Abulrob
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Jodi L McBride
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, USA; Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA
| | - Blair R Leavitt
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada.
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3
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Arias-Alpizar G, Papadopoulou P, Rios X, Pulagam KR, Moradi MA, Pattipeiluhu R, Bussmann J, Sommerdijk N, Llop J, Kros A, Campbell F. Phase-Separated Liposomes Hijack Endogenous Lipoprotein Transport and Metabolism Pathways to Target Subsets of Endothelial Cells In Vivo. Adv Healthc Mater 2022; 12:e2202709. [PMID: 36565694 DOI: 10.1002/adhm.202202709] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/14/2022] [Indexed: 12/25/2022]
Abstract
Plasma lipid transport and metabolism are essential to ensure correct cellular function throughout the body. Dynamically regulated in time and space, the well-characterized mechanisms underpinning plasma lipid transport and metabolism offers an enticing, but as yet underexplored, rationale to design synthetic lipid nanoparticles with inherent cell/tissue selectivity. Herein, a systemically administered liposome formulation, composed of just two lipids, that is capable of hijacking a triglyceride lipase-mediated lipid transport pathway resulting in liposome recognition and uptake within specific endothelial cell subsets is described. In the absence of targeting ligands, liposome-lipase interactions are mediated by a unique, phase-separated ("parachute") liposome morphology. Within the embryonic zebrafish, selective liposome accumulation is observed at the developing blood-brain barrier. In mice, extensive liposome accumulation within the liver and spleen - which is reduced, but not eliminated, following small molecule lipase inhibition - supports a role for endothelial lipase but highlights these liposomes are also subject to significant "off-target" by reticuloendothelial system organs. Overall, these compositionally simplistic liposomes offer new insights into the discovery and design of lipid-based nanoparticles that can exploit endogenous lipid transport and metabolism pathways to achieve cell selective targeting in vivo.
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Affiliation(s)
- Gabriela Arias-Alpizar
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden, 2300, The Netherlands.,Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, P.O. Box 9502, Leiden, 2300, The Netherlands
| | - Panagiota Papadopoulou
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden, 2300, The Netherlands
| | - Xabier Rios
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), San Sebastián, 20014, Spain
| | - Krishna Reddy Pulagam
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), San Sebastián, 20014, Spain
| | - Mohammad-Amin Moradi
- Materials and Interface Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600, The Netherlands
| | - Roy Pattipeiluhu
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden, 2300, The Netherlands
| | - Jeroen Bussmann
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden, 2300, The Netherlands.,Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, P.O. Box 9502, Leiden, 2300, The Netherlands
| | - Nico Sommerdijk
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, 6525, The Netherlands.,Electron Microscopy Centre, Radboudumc Technology Center Microscopy, Radboud University Medical Center, Geert Grooteplein Zuid 28, Nijmegen, 6525, The Netherlands
| | - Jordi Llop
- Materials and Interface Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600, The Netherlands
| | - Alexander Kros
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden, 2300, The Netherlands
| | - Frederick Campbell
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden, 2300, The Netherlands
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4
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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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5
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Abe RJ, Abe JI, Nguyen MTH, Olmsted-Davis EA, Mamun A, Banerjee P, Cooke JP, Fang L, Pownall H, Le NT. Free Cholesterol Bioavailability and Atherosclerosis. Curr Atheroscler Rep 2022; 24:323-336. [PMID: 35332444 PMCID: PMC9050774 DOI: 10.1007/s11883-022-01011-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2022] [Indexed: 11/30/2022]
Abstract
PURPOSE OF REVIEW As both a cholesterol acceptor and carrier in the reverse cholesterol transport (RCT) pathway, high-density lipoprotein (HDL) is putatively atheroprotective. However, current pharmacological therapies to increase plasma HDL cholesterol (HDL-c) concentration have paradoxically failed to prevent or reduce atherosclerosis and cardiovascular disease (CVD). Given that free cholesterol (FC) transfer between surfaces of lipoproteins and cells is reversible, excess plasma FC can be transferred to the cells of peripheral tissue sites resulting in atherosclerosis. Here, we summarize potential mechanisms contributing to this paradox and highlight the role of excess free cholesterol (FC) bioavailability in atherosclerosis vs. atheroprotection. RECENT FINDINGS Recent findings have established a complex relationship between HDL-c concentration and atherosclerosis. Systemic scavenger receptor class B type 1 (SR-B1) knock out (KO) mice exhibit with increased diet-induced atherosclerosis despite having an elevated plasma HDL-c concentration compared to wild type (WT) mice. The greater bioavailability of HDL-FC in SR-B1 vs. WT mice is associated with a higher FC content in multiple cell types and tissue sites. These results suggest that dysfunctional HDL with high FC bioavailability is atheroprone despite high HDL-c concentration. Past oversimplification of HDL-c involvement in cholesterol transport has led to the failures in HDL targeted therapy. Evidence suggests that FC-mediated functionality of HDL is of higher importance than its quantity; as a result, deciphering the regulatory mechanisms by which HDL-FC bioavailability can induce atherosclerosis can have far-reaching clinical implications.
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Affiliation(s)
- Rei J Abe
- Center for Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, USA
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Jun-Ichi Abe
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Minh T H Nguyen
- Center for Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, USA
- University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | | | - Abrar Mamun
- Center for Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, USA
| | - Priyanka Banerjee
- Center for Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, USA
| | - John P Cooke
- Center for Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, USA
- Weill Cornell Medicine, New York, NY, USA
| | - Longhou Fang
- Center for Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, USA
- Weill Cornell Medicine, New York, NY, USA
| | - Henry Pownall
- Weill Cornell Medicine, New York, NY, USA
- Center for Bioenergetics, Department of Medicine, Houston Methodist Research Institute, Houston, TX, USA
| | - Nhat-Tu Le
- Center for Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, USA.
- Weill Cornell Medicine, New York, NY, USA.
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6
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Axmann M, Plochberger B, Mikula M, Weber F, Strobl WM, Stangl H. Plasma Membrane Lipids: An Important Binding Site for All Lipoprotein Classes. MEMBRANES 2021; 11:membranes11110882. [PMID: 34832111 PMCID: PMC8622984 DOI: 10.3390/membranes11110882] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/12/2021] [Accepted: 11/12/2021] [Indexed: 12/23/2022]
Abstract
Cholesterol is one of the main constituents of plasma membranes; thus, its supply is of utmost importance. This review covers the known mechanisms of cholesterol transfer from circulating lipoprotein particles to the plasma membrane, and vice versa. To achieve homeostasis, the human body utilizes cellular de novo synthesis and extracellular transport particles for supply of cholesterol and other lipids via the blood stream. These lipoprotein particles can be classified according to their density: chylomicrons, very low, low, and high-density lipoprotein (VLDL, LDL, and HDL, respectively). They deliver and receive their lipid loads, most importantly cholesterol, to and from cells by several redundant routes. Defects in one of these pathways (e.g., due to mutations in receptors) usually are not immediately fatal. Several redundant pathways, at least temporarily, compensate for the loss of one or more of them, but the defects trigger systemic diseases, such as atherosclerosis later on. Recently, intracellular membrane–membrane contact sites were shown to be involved in intracellular cholesterol transfer and the plasma membrane itself has been proposed to act as a binding site for lipoprotein-mediated cargo unloading.
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Affiliation(s)
- Markus Axmann
- School of Medical Engineering and Applied Social Sciences, University of Applied Sciences Upper Austria, Garnisonstrasse 21, 4020 Linz, Austria; (M.A.); (B.P.); (F.W.)
| | - Birgit Plochberger
- School of Medical Engineering and Applied Social Sciences, University of Applied Sciences Upper Austria, Garnisonstrasse 21, 4020 Linz, Austria; (M.A.); (B.P.); (F.W.)
| | - Mario Mikula
- Center for Pathobiochemistry and Genetics, Institute for Medical Genetics, Medical University of Vienna, Währingerstrasse 10, 1090 Vienna, Austria;
| | - Florian Weber
- School of Medical Engineering and Applied Social Sciences, University of Applied Sciences Upper Austria, Garnisonstrasse 21, 4020 Linz, Austria; (M.A.); (B.P.); (F.W.)
| | - Witta Monika Strobl
- Center for Pathobiochemistry and Genetics, Institute for Medical Chemistry, Medical University of Vienna, Währingerstrasse 10, 1090 Vienna, Austria;
| | - Herbert Stangl
- Center for Pathobiochemistry and Genetics, Institute for Medical Chemistry, Medical University of Vienna, Währingerstrasse 10, 1090 Vienna, Austria;
- Correspondence:
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7
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Wainwright L, Hargreaves IP, Georgian AR, Turner C, Dalton RN, Abbott NJ, Heales SJR, Preston JE. CoQ 10 Deficient Endothelial Cell Culture Model for the Investigation of CoQ 10 Blood-Brain Barrier Transport. J Clin Med 2020; 9:jcm9103236. [PMID: 33050406 PMCID: PMC7601674 DOI: 10.3390/jcm9103236] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/02/2020] [Accepted: 10/06/2020] [Indexed: 12/31/2022] Open
Abstract
Primary coenzyme Q10 (CoQ10) deficiency is unique among mitochondrial respiratory chain disorders in that it is potentially treatable if high-dose CoQ10 supplements are given in the early stages of the disease. While supplements improve peripheral abnormalities, neurological symptoms are only partially or temporarily ameliorated. The reasons for this refractory response to CoQ10 supplementation are unclear, however, a contributory factor may be the poor transfer of CoQ10 across the blood-brain barrier (BBB). The aim of this study was to investigate mechanisms of CoQ10 transport across the BBB, using normal and pathophysiological (CoQ10 deficient) cell culture models. The study identifies lipoprotein-associated CoQ10 transcytosis in both directions across the in vitro BBB. Uptake via SR-B1 (Scavenger Receptor) and RAGE (Receptor for Advanced Glycation Endproducts), is matched by efflux via LDLR (Low Density Lipoprotein Receptor) transporters, resulting in no "net" transport across the BBB. In the CoQ10 deficient model, BBB tight junctions were disrupted and CoQ10 "net" transport to the brain side increased. The addition of anti-oxidants did not improve CoQ10 uptake to the brain side. This study is the first to generate in vitro BBB endothelial cell models of CoQ10 deficiency, and the first to identify lipoprotein-associated uptake and efflux mechanisms regulating CoQ10 distribution across the BBB. The results imply that the uptake of exogenous CoQ10 into the brain might be improved by the administration of LDLR inhibitors, or by interventions to stimulate luminal activity of SR-B1 transporters.
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Affiliation(s)
- Luke Wainwright
- UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK;
| | - Iain P. Hargreaves
- Neurometabolic Unit, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, London WC1N 3BG, UK;
- Department of Pharmacy and Biomolecular Science, Liverpool John Moores University, Liverpool L3 5UA, UK
| | - Ana R. Georgian
- School of Cancer and Pharmaceutical Sciences, King’s College London, London SE1 9NH, UK; (A.R.G.); (N.J.A.)
| | - Charles Turner
- Evelina London Children’s Hospital, Guy’s and St. Thomas’ NHS Foundation Trust, London SE1 7EH, UK; (C.T.); (R.N.D.)
| | - R. Neil Dalton
- Evelina London Children’s Hospital, Guy’s and St. Thomas’ NHS Foundation Trust, London SE1 7EH, UK; (C.T.); (R.N.D.)
| | - N. Joan Abbott
- School of Cancer and Pharmaceutical Sciences, King’s College London, London SE1 9NH, UK; (A.R.G.); (N.J.A.)
| | - Simon J. R. Heales
- Neurometabolic Unit, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, London WC1N 3BG, UK;
- UCL Great Ormond Street Institute of Child Health, University College London, London WC1E 6BT, UK;
| | - Jane E. Preston
- School of Cancer and Pharmaceutical Sciences, King’s College London, London SE1 9NH, UK; (A.R.G.); (N.J.A.)
- Correspondence: ; Tel.: +44-207-848-4881
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8
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Chuang ST, Cruz S, Narayanaswami V. Reconfiguring Nature's Cholesterol Accepting Lipoproteins as Nanoparticle Platforms for Transport and Delivery of Therapeutic and Imaging Agents. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E906. [PMID: 32397159 PMCID: PMC7279153 DOI: 10.3390/nano10050906] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/27/2020] [Accepted: 04/29/2020] [Indexed: 12/13/2022]
Abstract
Apolipoproteins are critical structural and functional components of lipoproteins, which are large supramolecular assemblies composed predominantly of lipids and proteins, and other biomolecules such as nucleic acids. A signature feature of apolipoproteins is the preponderance of amphipathic α-helical motifs that dictate their ability to make extensive non-covalent inter- or intra-molecular helix-helix interactions in lipid-free states or helix-lipid interactions with hydrophobic biomolecules in lipid-associated states. This review focuses on the latter ability of apolipoproteins, which has been capitalized on to reconstitute synthetic nanoscale binary/ternary lipoprotein complexes composed of apolipoproteins/peptides and lipids that mimic native high-density lipoproteins (HDLs) with the goal to transport drugs. It traces the historical development of our understanding of these nanostructures and how the cholesterol accepting property of HDL has been reconfigured to develop them as drug-loading platforms. The review provides the structural perspective of these platforms with different types of apolipoproteins and an overview of their synthesis. It also examines the cargo that have been loaded into the core for therapeutic and imaging purposes. Finally, it lays out the merits and challenges associated with apolipoprotein-based nanostructures with a future perspective calling for a need to develop "zip-code"-based delivery for therapeutic and diagnostic applications.
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Affiliation(s)
| | | | - Vasanthy Narayanaswami
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Blvd, Long Beach, CA 90840, USA; (S.T.C.); (S.C.)
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9
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Dang AT, He W, Ivey DB, Coleman MA, Kuhl TL. Lipid and Protein Transfer between Nanolipoprotein Particles and Supported Lipid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:12071-12078. [PMID: 31442053 PMCID: PMC7024587 DOI: 10.1021/acs.langmuir.9b01288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A nanolipoprotein particle (NLP) is a lipid bilayer disc stabilized by two amphipathic "scaffold" apolipoproteins. It has been most notably utilized as a tool for solubilizing a variety of membrane proteins while preserving structural and functional properties. Transfer of functional proteins from NLPs into model membrane systems such as supported lipid bilayers (SLBs) would enable new opportunities, for example, two-dimensional protein crystallization and studies on protein-protein interactions. This work used fluorescence microscopy and atomic force microscopy to investigate the interaction between NLPs and SLBs. When incubated with SLBs, NLPs were found to spontaneously deliver lipid and protein cargo. The impact of membrane composition on lipid exchange was explored, revealing a positive correlation between the magnitude of lipid transfer and concentration of defects in the target SLB. Incorporation of lipids capable of binding specifically to polyhistidine tags encoded into the apolipoproteins also boosted transfer of NLP cargo. Optimal conditions for lipid and protein delivery from NLPs to SLBs are proposed based on interaction mechanisms.
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Affiliation(s)
- Amanda T. Dang
- Department of Materials Science and Engineering, University of California, Davis CA 95616
| | - Wei He
- Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Daniela B. Ivey
- Department of Chemical Engineering, University of California, Davis CA 95616
| | | | - Tonya L. Kuhl
- Department of Chemical Engineering, University of California, Davis CA 95616
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10
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Sahebi R, Hassanian SM, Ghayour‐Mobarhan M, Farrokhi E, Rezayi M, Samadi S, Bahramian S, Ferns GA, Avan A. Scavenger receptor Class B type I as a potential risk stratification biomarker and therapeutic target in cardiovascular disease. J Cell Physiol 2019; 234:16925-16932. [DOI: 10.1002/jcp.28393] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 12/14/2022]
Affiliation(s)
- Reza Sahebi
- Department of Modern Sciences and Technologies, Faculty of Medicine Mashhad University of Medical Sciences Mashhad Iran
- Department of Molecular Medicine, School of Advanced Technologies Shahrekord University of Medical Sciences Shahrekord Iran
| | - Seyed Mahdi Hassanian
- Metabolic Syndrome Research Center Mashhad University of Medical Sciences Mashhad Iran
| | - Majid Ghayour‐Mobarhan
- Department of Modern Sciences and Technologies, Faculty of Medicine Mashhad University of Medical Sciences Mashhad Iran
- Metabolic Syndrome Research Center Mashhad University of Medical Sciences Mashhad Iran
| | - Effat Farrokhi
- Department of Molecular Medicine, School of Advanced Technologies Shahrekord University of Medical Sciences Shahrekord Iran
| | - Majid Rezayi
- Metabolic Syndrome Research Center Mashhad University of Medical Sciences Mashhad Iran
| | - Sara Samadi
- Department of Modern Sciences and Technologies, Faculty of Medicine Mashhad University of Medical Sciences Mashhad Iran
| | - Shabbou Bahramian
- Stem Cell Research Center Golestan University of Medical Sciences Gorgan Iran
| | - Gordon A. Ferns
- Division of Medical Education Brighton & Sussex Medical School, Falmer Brighton Sussex
| | - Amir Avan
- Metabolic Syndrome Research Center Mashhad University of Medical Sciences Mashhad Iran
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11
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Plochberger B, Axmann M, Röhrl C, Weghuber J, Brameshuber M, Rossboth BK, Mayr S, Ros R, Bittman R, Stangl H, Schütz GJ. Direct observation of cargo transfer from HDL particles to the plasma membrane. Atherosclerosis 2018; 277:53-59. [PMID: 30173079 DOI: 10.1016/j.atherosclerosis.2018.08.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/02/2018] [Accepted: 08/24/2018] [Indexed: 10/28/2022]
Abstract
BACKGROUND AND AIMS Exchange of cholesterol between high-density lipoprotein (HDL) particles and cells is a key process for maintaining cellular cholesterol homeostasis. Recently, we have shown that amphiphilic cargo derived from HDL can be transferred directly to lipid bilayers. Here we pursued this work using a fluorescence-based method to directly follow cargo transfer from HDL particles to the cell membrane. METHODS HDL was either immobilized on surfaces or added directly to cells, while transfer of fluorescent cargo was visualized via fluorescence imaging. RESULTS In Chinese hamster ovary (CHO) cells expressing the scavenger receptor class B type 1 (SR-B1), transfer of amphiphilic cargo from HDL particles to the plasma membrane was observed immediately after contact, whereas hydrophobic cargo remained associated with the particles; about 60% of the amphiphilic cargo of surface-bound HDL was transferred to the plasma membrane. Essentially no cargo transfer was observed in cells with low endogenous SR-B1 expression. Interestingly, transfer of fluorescently-labeled cholesterol was also facilitated by using an artificial linker to bind HDL to the cell surface. CONCLUSIONS Our data hence indicate that the tethering function of SR-B1 is sufficient for efficient transfer of free cholesterol to the plasma membrane.
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Affiliation(s)
- Birgit Plochberger
- TU Wien, Institute of Applied Physics, Vienna, 1040, Austria; Upper Austria University of Applied Sciences, Campus Linz, Garnisonstrasse 21, 4020, Linz, Austria
| | - Markus Axmann
- Medical University of Vienna, Center for Pathobiochemistry and Genetics, Institute of Medical Chemistry, Vienna, 1090, Austria
| | - Clemens Röhrl
- Medical University of Vienna, Center for Pathobiochemistry and Genetics, Institute of Medical Chemistry, Vienna, 1090, Austria
| | - Julian Weghuber
- Upper Austria University of Applied Sciences, Campus Wels, Stelzhamerstraße 23, 4600, Wels, Austria
| | | | | | - Sandra Mayr
- Upper Austria University of Applied Sciences, Campus Linz, Garnisonstrasse 21, 4020, Linz, Austria
| | - Robert Ros
- Arizona State University, Department of Physics, Tempe, AZ, 85287-1504, USA
| | - Robert Bittman
- Queens College of the City University of New York, Department of Chemistry and Biochemistry, Flushing, NY, 11367, USA
| | - Herbert Stangl
- Medical University of Vienna, Center for Pathobiochemistry and Genetics, Institute of Medical Chemistry, Vienna, 1090, Austria.
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12
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Zhang H, Qiao L, Luo G. Characterization of apolipoprotein C1 in hepatitis C virus infection and morphogenesis. Virology 2018; 524:1-9. [PMID: 30130702 DOI: 10.1016/j.virol.2018.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/05/2018] [Accepted: 08/05/2018] [Indexed: 12/12/2022]
Abstract
Previous studies have shown that apolipoprotein C1 (apoC1)-specific antibodies precipitated hepatitis C virus (HCV) and neutralized HCV infectivity, suggesting that apoC1 is a HCV component. However, the importance of apoC1 in the HCV life cycle has not been experimentally examined. In the present study, we sought to determine the role of apoC1 in the HCV infection and morphogenesis by knocking out the apoC1 gene using the CRISPR/Cas9 system. Strikingly, apoC1 gene knockout markedly enhanced apoE expression. As a result, apoC1 gene knockout per se didn't significantly affect HCV infection or morphogenesis, probably ascribing to its redundant functions with apoE. However, knockout of apoC1 gene potentiated the impairment of HCV infection and/or morphogenesis by apoE-specific small interfering RNAs. Additionally, a recombinant apoC1 protein efficiently blocked HCV infection. Collectively, these findings suggest that apoC1 and apoE have redundant functions in the HCV infection and morphogenesis.
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Affiliation(s)
- Han Zhang
- Department of Microbiology, Peking University School of Basic Medical Sciences, Beijing 100191, China
| | - Luhua Qiao
- Department of Microbiology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, United States
| | - Guangxiang Luo
- Department of Microbiology, Peking University School of Basic Medical Sciences, Beijing 100191, China; Department of Microbiology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, United States.
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13
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Shen WJ, Asthana S, Kraemer FB, Azhar S. Scavenger receptor B type 1: expression, molecular regulation, and cholesterol transport function. J Lipid Res 2018; 59:1114-1131. [PMID: 29720388 DOI: 10.1194/jlr.r083121] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/26/2018] [Indexed: 12/16/2022] Open
Abstract
Cholesterol is required for maintenance of plasma membrane fluidity and integrity and for many cellular functions. Cellular cholesterol can be obtained from lipoproteins in a selective pathway of HDL-cholesteryl ester (CE) uptake without parallel apolipoprotein uptake. Scavenger receptor B type 1 (SR-B1) is a cell surface HDL receptor that mediates HDL-CE uptake. It is most abundantly expressed in liver, where it provides cholesterol for bile acid synthesis, and in steroidogenic tissues, where it delivers cholesterol needed for storage or steroidogenesis in rodents. SR-B1 transcription is regulated by trophic hormones in the adrenal gland, ovary, and testis; in the liver and elsewhere, SR-B1 is subject to posttranscriptional and posttranslational regulation. SR-B1 operates in several metabolic processes and contributes to pathogenesis of atherosclerosis, inflammation, hepatitis C virus infection, and other conditions. Here, we summarize characteristics of the selective uptake pathway and involvement of microvillar channels as facilitators of selective HDL-CE uptake. We also present the potential mechanisms of SR-B1-mediated selective cholesterol transport; the transcriptional, posttranscriptional, and posttranslational regulation of SR-B1; and the impact of gene variants on expression and function of human SR-B1. A better understanding of this unique pathway and SR-B1's role may yield improved therapies for a wide variety of conditions.
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Affiliation(s)
- Wen-Jun Shen
- Geriatric Research, Education, and Clinical Research Center (GRECC), Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 and Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Stanford, CA 94305
| | - Shailendra Asthana
- Drug Discovery Research Center (DDRC), Translational Health Science and Technology Institute (THSTI), NCR Biotech Science Cluster, Faridabad 121001, Haryana, India
| | - Fredric B Kraemer
- Geriatric Research, Education, and Clinical Research Center (GRECC), Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 and Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Stanford, CA 94305
| | - Salman Azhar
- Geriatric Research, Education, and Clinical Research Center (GRECC), Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 and Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Stanford, CA 94305
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14
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Plochberger B, Röhrl C, Preiner J, Rankl C, Brameshuber M, Madl J, Bittman R, Ros R, Sezgin E, Eggeling C, Hinterdorfer P, Stangl H, Schütz GJ. HDL particles incorporate into lipid bilayers - a combined AFM and single molecule fluorescence microscopy study. Sci Rep 2017; 7:15886. [PMID: 29162870 PMCID: PMC5698431 DOI: 10.1038/s41598-017-15949-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 11/03/2017] [Indexed: 11/09/2022] Open
Abstract
The process, how lipids are removed from the circulation and transferred from high density lipoprotein (HDL) – a main carrier of cholesterol in the blood stream – to cells, is highly complex. HDL particles are captured from the blood stream by the scavenger receptor, class B, type I (SR-BI), the so-called HDL receptor. The details in subsequent lipid-transfer process, however, have not yet been completely understood. The transfer has been proposed to occur directly at the cell surface across an unstirred water layer, via a hydrophobic channel in the receptor, or after HDL endocytosis. The role of the target lipid membrane for the transfer process, however, has largely been overlooked. Here, we studied at the single molecule level how HDL particles interact with synthetic lipid membranes. Using (high-speed) atomic force microscopy and fluorescence correlation spectroscopy (FCS) we found out that, upon contact with the membrane, HDL becomes integrated into the lipid bilayer. Combined force and single molecule fluorescence microscopy allowed us to directly monitor the transfer process of fluorescently labelled amphiphilic lipid probe from HDL particles to the lipid bilayer upon contact.
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Affiliation(s)
- Birgit Plochberger
- TU Wien, Institute of Applied Physics, Vienna, 1040, Austria.,Johannes Kepler University Linz, Institute of Biophysics, Linz, 4020, Austria.,Upper Austria University of Applied Sciences, Campus Linz, Linz, 4020, Austria
| | - Clemens Röhrl
- Medical University of Vienna, Center for Pathobiochemistry and Genetics, Institute of Medical Chemistry, Vienna, 1090, Austria
| | - Johannes Preiner
- Upper Austria University of Applied Sciences, Campus Linz, Linz, 4020, Austria.,Center for Advanced Bioanalysis GmbH, Linz, 4020, Austria
| | | | | | - Josef Madl
- Johannes Kepler University Linz, Institute of Biophysics, Linz, 4020, Austria
| | - Robert Bittman
- Queens College of the City University of New York, Department of Chemistry and Biochemistry, Flushing, NY, 11367, USA
| | - Robert Ros
- Arizona State University, Department of Physics, Tempe, AZ, 85287-1504, USA
| | - Erdinc Sezgin
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany.,MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Peter Hinterdorfer
- Johannes Kepler University Linz, Institute of Biophysics, Linz, 4020, Austria
| | - Herbert Stangl
- Medical University of Vienna, Center for Pathobiochemistry and Genetics, Institute of Medical Chemistry, Vienna, 1090, Austria.
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15
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Baranova IN, Souza ACP, Bocharov AV, Vishnyakova TG, Hu X, Vaisman BL, Amar MJ, Chen Z, Remaley AT, Patterson AP, Yuen PST, Star RA, Eggerman TL. Human SR-BII mediates SAA uptake and contributes to SAA pro-inflammatory signaling in vitro and in vivo. PLoS One 2017; 12:e0175824. [PMID: 28423002 PMCID: PMC5396919 DOI: 10.1371/journal.pone.0175824] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 04/01/2017] [Indexed: 12/13/2022] Open
Abstract
Serum amyloid A (SAA) is an acute phase protein with cytokine-like and chemotactic properties, that is markedly up-regulated during various inflammatory conditions. Several receptors, including FPRL-1, TLR2, TLR4, RAGE, class B scavenger receptors, SR-BI and CD36, have been identified as SAA receptors. This study provides new evidence that SR-BII, splice variant of SR-BI, could function as an SAA receptor mediating its uptake and pro-inflammatory signaling. The uptake of Alexa Fluor488 SAA was markedly (~3 fold) increased in hSR-BII-expressing HeLa cells when compared with mock-transfected cells. The levels of SAA-induced interleukin-8 secretion by hSR-BII-expressing HEK293 cells were also significantly (~3-3.5 fold) higher than those detected in control cells. Moderately enhanced levels of phosphorylation of all three mitogen-activated protein kinases, ERK1/2, and p38 and JNK, were observed in hSR-BII-expressing cells following SAA stimulation when compared with control wild type cells. Transgenic mice with pLiv-11-directed liver/kidney overexpression of hSR-BI or hSR-BII were used to assess the in vivo role of each receptor in SAA-induced pro-inflammatory response in these organs. Six hours after intraperitoneal SAA injection both groups of transgenic mice demonstrated markedly higher (~2-5-fold) expression levels of inflammatory mediators in the liver and kidney compared to wild type mice. Histological examinations of hepatic and renal tissue from SAA-treated mice revealed moderate level of damage in the liver of both transgenic but not in the wild type mice. Activities of plasma transaminases, biomarkers of liver injury, were also moderately higher in hSR-B transgenic mice when compared to wild type mice. Our findings identify hSR-BII as a functional SAA receptor that mediates SAA uptake and contributes to its pro-inflammatory signaling via the MAPKs-mediated signaling pathways.
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Affiliation(s)
- Irina N. Baranova
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ana C. P. Souza
- Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Alexander V. Bocharov
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Tatyana G. Vishnyakova
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Xuzhen Hu
- Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Boris L. Vaisman
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Marcelo J. Amar
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Zhigang Chen
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Alan T. Remaley
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Amy P. Patterson
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Peter S. T. Yuen
- Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Robert A. Star
- Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Thomas L. Eggerman
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America
- Division of Diabetes, Endocrinology and Metabolic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
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16
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Vasquez M, Fioravanti J, Aranda F, Paredes V, Gomar C, Ardaiz N, Fernandez-Ruiz V, Méndez M, Nistal-Villan E, Larrea E, Gao Q, Gonzalez-Aseguinolaza G, Prieto J, Berraondo P. Interferon alpha bioactivity critically depends on Scavenger receptor class B type I function. Oncoimmunology 2016; 5:e1196309. [PMID: 27622065 PMCID: PMC5007953 DOI: 10.1080/2162402x.2016.1196309] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/10/2016] [Accepted: 05/27/2016] [Indexed: 12/11/2022] Open
Abstract
Scavenger receptor class B type I (SR-B1) binds pathogen-associated molecular patterns participating in the regulation of the inflammatory reaction but there is no information regarding potential interactions between SR-B1 and the interferon system. Herein, we report that SR-B1 ligands strongly regulate the transcriptional response to interferon α (IFNα) and enhance its antiviral and antitumor activity. This effect was mediated by the activation of TLR2 and TLR4 as it was annulled by the addition of anti-TLR2 or anti-TLR4 blocking antibodies. In vivo, we maximized the antitumor activity of IFNα co-expressing in the liver a SR-B1 ligand and IFNα by adeno-associated viruses. This gene therapy strategy eradicated liver metastases from colon cancer with reduced toxicity. On the other hand, genetic and pharmacological inhibition of SR-B1 blocks the clathrin-dependent interferon receptor recycling pathway with a concomitant reduction in IFNα signaling and bioactivity. This effect can be applied to enhance cancer immunotherapy with oncolytic viruses. Indeed, SR-B1 antagonists facilitate replication of oncolytic viruses amplifying their tumoricidal potential. In conclusion, SR-B1 agonists behave as IFNα enhancers while SR-B1 inhibitors dampen IFNα activity. These results demonstrate that SR-B1 is a suitable pharmacology target to enhance cancer immunotherapy based on IFNα and oncolytic viruses.
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Affiliation(s)
- Marcos Vasquez
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Navarra Institute for Health Research (IdiSNA) , Pamplona, Navarra, Spain
| | - Jessica Fioravanti
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Navarra Institute for Health Research (IdiSNA) , Pamplona, Navarra, Spain
| | - Fernando Aranda
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Navarra Institute for Health Research (IdiSNA) , Pamplona, Navarra, Spain
| | - Vladimir Paredes
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Navarra Institute for Health Research (IdiSNA), Pamplona, Navarra, Spain; Centro Médico Nacional La Raza, IMSS, México DF, Mexico
| | - Celia Gomar
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Navarra Institute for Health Research (IdiSNA) , Pamplona, Navarra, Spain
| | - Nuria Ardaiz
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Navarra Institute for Health Research (IdiSNA) , Pamplona, Navarra, Spain
| | - Veronica Fernandez-Ruiz
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Navarra Institute for Health Research (IdiSNA) , Pamplona, Navarra, Spain
| | - Miriam Méndez
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Navarra Institute for Health Research (IdiSNA) , Pamplona, Navarra, Spain
| | - Estanislao Nistal-Villan
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Navarra Institute for Health Research (IdiSNA) , Pamplona, Navarra, Spain
| | - Esther Larrea
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Navarra Institute for Health Research (IdiSNA), Pamplona, Navarra, Spain; Instituto de Salud Tropical, University of Navarra, Pamplona, Navarra, Spain
| | - Qinshan Gao
- Department of Microbiology, Icahn School of Medicine at Mount Sinai , New York, NY, USA
| | - Gloria Gonzalez-Aseguinolaza
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Navarra Institute for Health Research (IdiSNA) , Pamplona, Navarra, Spain
| | - Jesus Prieto
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Navarra Institute for Health Research (IdiSNA) , Pamplona, Navarra, Spain
| | - Pedro Berraondo
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Navarra Institute for Health Research (IdiSNA) , Pamplona, Navarra, Spain
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17
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Bocharov AV, Wu T, Baranova IN, Birukova AA, Sviridov D, Vishnyakova TG, Remaley AT, Eggerman TL, Patterson AP, Birukov KG. Synthetic Amphipathic Helical Peptides Targeting CD36 Attenuate Lipopolysaccharide-Induced Inflammation and Acute Lung Injury. THE JOURNAL OF IMMUNOLOGY 2016; 197:611-9. [PMID: 27316682 DOI: 10.4049/jimmunol.1401028] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 04/28/2016] [Indexed: 01/07/2023]
Abstract
Synthetic amphipathic helical peptides (SAHPs) designed as apolipoprotein A-I mimetics are known to bind to class B scavenger receptors (SR-Bs), SR-BI, SR-BII, and CD36, receptors that mediate lipid transport and facilitate pathogen recognition. In this study, we evaluated SAHPs, selected for targeting human CD36, by their ability to attenuate LPS-induced inflammation, endothelial barrier dysfunction, and acute lung injury (ALI). L37pA, which targets CD36 and SR-BI equally, inhibited LPS-induced IL-8 secretion and barrier dysfunction in cultured endothelial cells while reducing lung neutrophil infiltration by 40% in a mouse model of LPS-induced ALI. A panel of 20 SAHPs was tested in HEK293 cell lines stably transfected with various SR-Bs to identify SAHPs with preferential selectivity toward CD36. Among several SAHPs targeting both SR-BI/BII and CD36 receptors, ELK-B acted predominantly through CD36. Compared with L37pA, 5A, and ELK SAHPs, ELK-B was most effective in reducing the pulmonary barrier dysfunction, neutrophil migration into the lung, and lung inflammation induced by LPS. We conclude that SAHPs with relative selectivity toward CD36 are more potent at inhibiting acute pulmonary inflammation and dysfunction. These data indicate that therapeutic strategies using SAHPs targeting CD36, but not necessarily mimicking all apolipoprotein A-I functions, may be considered a possible new treatment approach for inflammation-induced ALI and pulmonary edema.
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Affiliation(s)
- Alexander V Bocharov
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892; National Heart, Lung, and Blood Institute, Bethesda, MD 20892;
| | - Tinghuai Wu
- Lung Injury Center, The University of Chicago, Chicago, IL 60637
| | - Irina N Baranova
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892
| | - Anna A Birukova
- Lung Injury Center, The University of Chicago, Chicago, IL 60637
| | - Denis Sviridov
- National Institute of Diabetes, Digestive, and Kidney Diseases, Bethesda, MD 20892; and
| | - Tatyana G Vishnyakova
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892
| | - Alan T Remaley
- National Heart, Lung, and Blood Institute, Bethesda, MD 20892
| | - Thomas L Eggerman
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892; National Institute of Diabetes, Digestive, and Kidney Diseases, Bethesda, MD 20892; and
| | - Amy P Patterson
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892; Office of Science Policy, Office of the Director, National Institutes of Health, Bethesda, MD 20892
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Hueging K, Weller R, Doepke M, Vieyres G, Todt D, Wölk B, Vondran FWR, Geffers R, Lauber C, Kaderali L, Penin F, Pietschmann T. Several Human Liver Cell Expressed Apolipoproteins Complement HCV Virus Production with Varying Efficacy Conferring Differential Specific Infectivity to Released Viruses. PLoS One 2015; 10:e0134529. [PMID: 26226615 PMCID: PMC4520612 DOI: 10.1371/journal.pone.0134529] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 07/09/2015] [Indexed: 02/08/2023] Open
Abstract
Apolipoprotein E (ApoE), an exchangeable apolipoprotein, is necessary for production of infectious Hepatitis C virus (HCV) particles. However, ApoE is not the only liver-expressed apolipoprotein and the role of other apolipoproteins for production of infectious HCV progeny is incompletely defined. Therefore, we quantified mRNA expression of human apolipoproteins in primary human hepatocytes. Subsequently, cDNAs encoding apolipoproteins were expressed in 293T/miR-122 cells to explore if they complement HCV virus production in cells that are non-permissive due to limiting endogenous levels of human apolipoproteins. Primary human hepatocytes expressed high mRNA levels of ApoA1, A2, C1, C3, E, and H. ApoA4, A5, B, D, F, J, L1, L2, L3, L4, L6, M, and O were expressed at intermediate levels, and C2, C4, and L5 were not detected. All members of the ApoA and ApoC family of lipoproteins complemented HCV virus production in HCV transfected 293T/miR-122 cells, albeit with significantly lower efficacy compared with ApoE. In contrast, ApoD expression did not support production of infectious HCV. Specific infectivity of released particles complemented with ApoA family members was significantly lower compared with ApoE. Moreover, the ratio of extracellular to intracellular infectious virus was significantly higher for ApoE compared to ApoA2 and ApoC3. Since apolipoproteins complementing HCV virus production share amphipathic alpha helices as common structural features we altered the two alpha helices of ApoC1. Helix breaking mutations in both ApoC1 helices impaired virus assembly highlighting a critical role of alpha helices in apolipoproteins supporting HCV assembly. In summary, various liver expressed apolipoproteins with amphipathic alpha helices complement HCV virus production in human non liver cells. Differences in the efficiency of virus assembly, the specific infectivity of released particles, and the ratio between extracellular and intracellular infectivity point to distinct characteristics of these apolipoproteins that influence HCV assembly and cell entry. This will guide future research to precisely pinpoint how apolipoproteins function during virus assembly and cell entry.
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Affiliation(s)
- Kathrin Hueging
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany
| | - Romy Weller
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany
| | - Mandy Doepke
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany
| | - Gabrielle Vieyres
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany
| | - Daniel Todt
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany
| | - Benno Wölk
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Florian W. R. Vondran
- Department of General, Visceral and Transplant Surgery, Hannover Medical School, Hannover, Germany
- Integrated Research and Treatment Center Transplantation (IFB-Tx), Hannover Medical School, Hannover, Germany
- German Centre for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Hannover, Germany
| | - Robert Geffers
- Research Group Genome Analytics, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Chris Lauber
- Institute for Medical Informatics and Biometry, Medical Faculty, Technische Universität Dresden, Dresden, Germany
| | - Lars Kaderali
- Institute for Medical Informatics and Biometry, Medical Faculty, Technische Universität Dresden, Dresden, Germany
| | - François Penin
- Institut de Biologie et Chimie des Protéines, Bases Moléculaires et Structurales des Systèmes Infectieux, UMR 5086, CNRS, Labex Ecofect, University of Lyon, Lyon, France
| | - Thomas Pietschmann
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany
- German Centre for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Hannover, Germany
- * E-mail:
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19
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Mei X, Atkinson D. Lipid-free Apolipoprotein A-I Structure: Insights into HDL Formation and Atherosclerosis Development. Arch Med Res 2015; 46:351-60. [PMID: 26048453 DOI: 10.1016/j.arcmed.2015.05.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 05/27/2015] [Indexed: 12/22/2022]
Abstract
Apolipoprotein A-I is the major protein in high-density lipoprotein (HDL) and plays an important role during the process of reverse cholesterol transport (RCT). Knowledge of the high-resolution structure of full-length apoA-I is vital for a molecular understanding of the function of HDL at the various steps of the RCT pathway. Due to the flexible nature of apoA-I and aggregation properties, the structure of full-length lipid-free apoA-I has evaded description for over three decades. Sequence analysis of apoA-I suggested that the amphipathic α-helix is the structural motif of exchangeable apolipoprotein, and NMR, X-ray and MD simulation studies have confirmed this. Different laboratories have used different methods to probe the secondary structure distribution and organization of both the lipid-free and lipid-bound apoA-I structure. Mutation analysis, synthetic peptide models, surface chemistry and crystal structures have converged on the lipid-free apoA-I domain structure and function: the N-terminal domain [1-184] forms a helix bundle while the C-terminal domain [185-243] mostly lacks defined structure and is responsible for initiating lipid-binding, aggregation and is also involved in cholesterol efflux. The first 43 residues of apoA-I are essential to stabilize the lipid-free structure. In addition, the crystal structure of C-terminally truncated apoA-I suggests a monomer-dimer conversation mechanism mediated through helix 5 reorganization and dimerization during the formation of HDL. Based on previous research, we have proposed a structural model for full-length monomeric apoA-I in solution and updated the HDL formation mechanism through three states. Mapping the known natural mutations on the full-length monomeric apoA-I model provides insight into atherosclerosis development through disruption of the N-terminal helix bundle or deletion of the C-terminal lipid-binding domain.
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Affiliation(s)
- Xiaohu Mei
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, USA
| | - David Atkinson
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, USA.
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20
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Goncalves A, Gontero B, Nowicki M, Margier M, Masset G, Amiot MJ, Reboul E. Micellar lipid composition affects micelle interaction with class B scavenger receptor extracellular loops. J Lipid Res 2015; 56:1123-33. [PMID: 25833688 DOI: 10.1194/jlr.m057612] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Indexed: 11/20/2022] Open
Abstract
Scavenger receptors (SRs) like cluster determinant 36 (CD36) and SR class B type I (SR-BI) play a debated role in lipid transport across the intestinal brush border membrane. We used surface plasmon resonance to analyze real-time interactions between the extracellular protein loops and various ligands ranging from single lipid molecules to mixed micelles. Micelles mimicking physiological structures were necessary for optimal binding to both the extracellular loop of CD36 (lCD36) and the extracellular loop of SR-BI (lSR-BI). Cholesterol, phospholipid, and fatty acid micellar content significantly modulated micelle binding to and dissociation from the transporters. In particular, high phospholipid micellar concentrations inhibited micelle binding to both receptors (-53.8 and -74.4% binding at 0.32 mM compared with 0.04 mM for lCD36 and lSR-BI, respectively, P < 0.05). The presence of fatty acids was crucial for micelle interactions with both proteins (94.4 and 81.3% binding with oleic acid for lCD36 and lSR-BI, respectively, P < 0.05) and fatty acid type substitution within the micelles was the component that most impacted micelle binding to the transporters. These effects were partly due to subsequent modifications in micellar size and surface electric charge, and could be correlated to micellar vitamin D uptake by Caco-2 cells. Our findings show for the first time that micellar lipid composition and micellar properties are key factors governing micelle interactions with SRs.
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Affiliation(s)
- Aurélie Goncalves
- INRA, UMR 1260 "Nutrition, Obesity and Risk of Thrombosis," F-13385 Marseille, France INSERM, UMR 1062, F-13385 Marseille, France Aix-Marseille Université, F-13385 Marseille, France
| | - Brigitte Gontero
- Aix-Marseille Université CNRS, BIP, UMR 7281, F-13402 Marseille, France
| | - Marion Nowicki
- INRA, UMR 1260 "Nutrition, Obesity and Risk of Thrombosis," F-13385 Marseille, France INSERM, UMR 1062, F-13385 Marseille, France Aix-Marseille Université, F-13385 Marseille, France
| | - Marielle Margier
- INRA, UMR 1260 "Nutrition, Obesity and Risk of Thrombosis," F-13385 Marseille, France INSERM, UMR 1062, F-13385 Marseille, France Aix-Marseille Université, F-13385 Marseille, France
| | - Gabriel Masset
- INRA, UMR 1260 "Nutrition, Obesity and Risk of Thrombosis," F-13385 Marseille, France INSERM, UMR 1062, F-13385 Marseille, France Aix-Marseille Université, F-13385 Marseille, France
| | - Marie-Josèphe Amiot
- INRA, UMR 1260 "Nutrition, Obesity and Risk of Thrombosis," F-13385 Marseille, France INSERM, UMR 1062, F-13385 Marseille, France Aix-Marseille Université, F-13385 Marseille, France
| | - Emmanuelle Reboul
- INRA, UMR 1260 "Nutrition, Obesity and Risk of Thrombosis," F-13385 Marseille, France INSERM, UMR 1062, F-13385 Marseille, France Aix-Marseille Université, F-13385 Marseille, France
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21
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Abstract
Most types of cells in the body do not express the capability of catabolizing cholesterol, so cholesterol efflux is essential for homeostasis. For instance, macrophages possess four pathways for exporting free (unesterified) cholesterol to extracellular high density lipoprotein (HDL). The passive processes include simple diffusion via the aqueous phase and facilitated diffusion mediated by scavenger receptor class B, type 1 (SR-BI). Active pathways are mediated by the ATP-binding cassette (ABC) transporters ABCA1 and ABCG1, which are membrane lipid translocases. The efflux of cellular phospholipid and free cholesterol to apolipoprotein A-I promoted by ABCA1 is essential for HDL biogenesis. Current understanding of the molecular mechanisms involved in these four efflux pathways is presented in this minireview.
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Affiliation(s)
- Michael C Phillips
- From the Division of Translational Medicine and Human Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-5158
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22
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Abstract
Cardiovascular disease (CVD) is the leading cause of death globally. For close to four decades, we have known that high density lipoprotein (HDL) levels are inversely correlated with the risk of CVD. HDL is a complex particle that consists of proteins, phospholipids, and cholesterol and has the ability to carry micro-RNAs. HDL is constantly undergoing remodelling throughout its life-span and carries out many functions. This review summarizes many of the different aspects of HDL from its assembly, the receptors it interacts with, along with the functions it performs and how it can be altered in disease. While HDL is a key cholesterol efflux particle, this review highlights the many other important functions of HDL in the innate immune system and details the potential therapeutic uses of HDL outside of CVD.
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23
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Leman LJ, Maryanoff BE, Ghadiri MR. Molecules that mimic apolipoprotein A-I: potential agents for treating atherosclerosis. J Med Chem 2013; 57:2169-96. [PMID: 24168751 DOI: 10.1021/jm4005847] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Certain amphipathic α-helical peptides can functionally mimic many of the properties of full-length apolipoproteins, thereby offering an approach to modulate high-density lipoprotein (HDL) for combating atherosclerosis. In this Perspective, we summarize the key findings and advances over the past 25 years in the development of peptides that mimic apolipoproteins, especially apolipoprotein A-I (apoA-I). This assemblage of information provides a reasonably clear picture of the state of the art in the apolipoprotein mimetic field, an appreciation of the potential for such agents in pharmacotherapy, and a sense of the opportunities for optimizing the functional properties of HDL.
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Affiliation(s)
- Luke J Leman
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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24
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Yuan Y, Wang W, Wang B, Zhu H, Zhang B, Feng M. Delivery of hydrophilic drug doxorubicin hydrochloride-targeted liver using apoAI as carrier. J Drug Target 2013; 21:367-74. [PMID: 23600747 DOI: 10.3109/1061186x.2012.757769] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
High-density lipoprotein (HDL) particles can deliver cholesterol from peripheral tissues to the liver through apolipoprotein A1 (Apo A1), which specifically binds to the scavenger receptor class B type 1 (SR-B1) receptor on the surface of hepatocytes. Therefore, ApoA1 can be potentially used to target drugs to the liver. In this study, we successfully loaded doxorubicin hydrochloride (Dox or Dox-HCl), which is a hydrophilic drug used in a wide variety of clinical applications, into the core of reconstituted HDL (rHDL prepared by apoAI and egg phospholipids) to form a doxorubicin-HDL complex (rHDL-Dox). The MTT assays showed that rHDL-Dox particles also had higher cytotoxicity against several cells lines compared to free drug or Dox encapsulated into liposomes. A cellular uptake assay demonstrated that rHDL-Dox had higher absorption in SR-BI receptor positive liver cells. Importantly, in vivo experiments showed that rHDL-Dox can reduce tumor growth more effectively than liposomes. In addition, an in vitro hemolysis assay showed that rHDL-Dox caused only limited hemolysis in the case of high doses. Taken together, our findings indicate that rHDL is a safe and effective drug delivery system for targeting liver.
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Affiliation(s)
- Yuan Yuan
- School of Pharmacy, Fudan University, Shanghai, China
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25
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Pécheur EI. Lipoprotein receptors and lipid enzymes in hepatitis C virus entry and early steps of infection. SCIENTIFICA 2012; 2012:709853. [PMID: 24278733 PMCID: PMC3820461 DOI: 10.6064/2012/709853] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 10/31/2012] [Indexed: 06/02/2023]
Abstract
Viruses are obligate intracellular agents that depend on host cells for successful propagation, hijacking cellular machineries to their own profit. The molecular interplay between host factors and invading viruses is a continuous coevolutionary process that determines viral host range and pathogenesis. The hepatitis C virus (HCV) is a strictly human pathogen, causing chronic liver injuries accompanied by lipid disorders. Upon infection, in addition to protein-protein and protein-RNA interactions usual for such a positive-strand RNA virus, HCV relies on protein-lipid interactions at multiple steps of its life cycle to establish persistent infection, making use of hepatic lipid pathways. This paper focuses on lipoproteins in HCV entry and on receptors and enzymes involved in lipid metabolism that HCV exploits to enter hepatocytes.
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Affiliation(s)
- Eve-Isabelle Pécheur
- Department of Mechanisms of Chronic Hepatitis B and C, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France
- Inserm U1052/CNRS UMR 5286, CRCL, Université de Lyon, 151 Cours Albert Thomas, 69424 Lyon Cedex 03, France
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26
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Leelahavanichkul A, Bocharov AV, Kurlander R, Baranova IN, Vishnyakova TG, Souza AC, Hu X, Doi K, Vaisman B, Amar M, Sviridov D, Chen Z, Remaley AT, Csako G, Patterson AP, Yuen PST, Star RA, Eggerman TL. Class B scavenger receptor types I and II and CD36 targeting improves sepsis survival and acute outcomes in mice. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012; 188:2749-58. [PMID: 22327076 PMCID: PMC3859147 DOI: 10.4049/jimmunol.1003445] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Class B scavenger receptors (SR-Bs), such as SR-BI/II or CD36, bind lipoproteins but also mediate bacterial recognition and phagocytosis. In evaluating whether blocking receptors can prevent intracellular bacterial proliferation, phagocyte cytotoxicity, and proinflammatory signaling in bacterial infection/sepsis, we found that SR-BI/II- or CD36-deficient phagocytes are characterized by a reduced intracellular bacterial survival and a lower cytokine response and were protected from bacterial cytotoxicity in the presence of antibiotics. Mice deficient in either SR-BI/II or CD36 are protected from antibiotic-treated cecal ligation and puncture (CLP)-induced sepsis, with greatly increased peritoneal granulocytic phagocyte survival (8-fold), a drastic diminution in peritoneal bacteria counts, and a 50-70% reduction in systemic inflammation (serum levels of IL-6, TNF-α, and IL-10) and organ damage relative to CLP in wild-type mice. The survival rate of CD36-deficient mice after CLP was 58% compared with 17% in control mice. When compensated for mineralocorticoid and glucocorticoid deficiency, SR-BI/II-deficient mice had nearly a 50% survival rate versus 5% in mineralo-/glucocorticoid-treated controls. Targeting SR-B receptors with L-37pA, a peptide that functions as an antagonist of SR-BI/II and CD36 receptors, also increased peritoneal granulocyte counts, as well as reduced peritoneal bacteria and bacterium-induced cytokine secretion. In the CLP mouse sepsis model, L-37pA improved survival from 6 to 27%, reduced multiple organ damage, and improved kidney function. These results demonstrate that the reduction of both SR-BI/II- and CD36-dependent bacterial invasion and inflammatory response in the presence of antibiotic treatment results in granulocyte survival and local bacterial containment, as well as reduces systemic inflammation and organ damage and improves animal survival during severe infections.
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Affiliation(s)
- Asada Leelahavanichkul
- Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, MD 20892
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Alexander V. Bocharov
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health (NIH), Bethesda, MD 20892
| | - Roger Kurlander
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health (NIH), Bethesda, MD 20892
| | - Irina N. Baranova
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health (NIH), Bethesda, MD 20892
| | - Tatyana G. Vishnyakova
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health (NIH), Bethesda, MD 20892
| | - Ana C.P. Souza
- Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, MD 20892
| | - Xuzhen Hu
- Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, MD 20892
| | - Kent Doi
- Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, MD 20892
| | - Boris Vaisman
- National Heart, Lung, and Blood Institute, National Institutes of Health (NIH), Bethesda, MD 20892
| | - Marcelo Amar
- National Heart, Lung, and Blood Institute, National Institutes of Health (NIH), Bethesda, MD 20892
| | - Denis Sviridov
- National Heart, Lung, and Blood Institute, National Institutes of Health (NIH), Bethesda, MD 20892
| | - Zhigang Chen
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health (NIH), Bethesda, MD 20892
| | - Alan T. Remaley
- National Heart, Lung, and Blood Institute, National Institutes of Health (NIH), Bethesda, MD 20892
| | - Gyorgy Csako
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health (NIH), Bethesda, MD 20892
| | - Amy P. Patterson
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health (NIH), Bethesda, MD 20892
- Office of Biotechnology Activities, Office of the Director, National Institutes of Health (NIH), Bethesda, MD 20892
| | - Peter S. T. Yuen
- Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, MD 20892
| | - Robert A Star
- Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, MD 20892
| | - Thomas L. Eggerman
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health (NIH), Bethesda, MD 20892
- Division of Diabetes, Endocrinology, and Metabolic Diseases, NIDDK, National Institutes of Health (NIH), Bethesda, MD 20892
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27
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Baranova IN, Vishnyakova TG, Bocharov AV, Leelahavanichkul A, Kurlander R, Chen Z, Souza ACP, Yuen PST, Star RA, Csako G, Patterson AP, Eggerman TL. Class B scavenger receptor types I and II and CD36 mediate bacterial recognition and proinflammatory signaling induced by Escherichia coli, lipopolysaccharide, and cytosolic chaperonin 60. THE JOURNAL OF IMMUNOLOGY 2011; 188:1371-80. [PMID: 22205027 DOI: 10.4049/jimmunol.1100350] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Class B scavenger receptors (SR-B) are lipoprotein receptors that also mediate pathogen recognition, phagocytosis, and clearance as well as pathogen-induced signaling. In this study we report that three members of the SR-B family, namely, CLA-1, CLA-2, and CD36, mediate recognition of bacteria not only through interaction with cell wall LPS but also with cytosolic chaperonin 60. HeLa cells stably transfected with any of these SR-Bs demonstrated markedly (3- to 5-fold) increased binding and endocytosis of Escherichia coli, LPS, and chaperonin 60 (GroEL) as revealed by both FACS analysis and confocal microscopy imaging. Increased pathogen (E. coli, LPS, and GroEL) binding to SR-Bs was also associated with the dose-dependent stimulation of cytokine secretion in the order of CD36 > CLA-2 > CLA-1 in HEK293 cells. Pathogen-induced IL-6-secretion was reduced in macrophages from CD36- and SR-BI/II-null mice by 40-50 and 30-40%, respectively. Intravenous GroEL administration increased plasma IL-6 and CXCL1 levels in mice. The cytokine responses were 40-60% lower in CD36(-/-) relative to wild-type mice, whereas increased cytokine responses were found in SR-BI/II(-/-) mice. While investigating the discrepancy of in vitro versus in vivo data in SR-BI/II deficiency, SR-BI/II(-/-) mice were found to respond to GroEL administration without increases in either plasma corticosterone or aldosterone as normally seen in wild-type mice. SR-BI/II(-/-) mice with mineralocorticoid replacement demonstrated an ∼40-50% reduction in CXCL1 and IL-6 responses. These results demonstrate that, by recognizing and mediating inflammatory signaling of both bacterial cell wall LPS and cytosolic GroEL, all three SR-B family members play important roles in innate immunity and host defense.
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Affiliation(s)
- Irina N Baranova
- Department of Laboratory Medicine, Clinical Center, National Institute of Diabetes and Digestive Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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28
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Exoplasmic cysteine Cys384 of the HDL receptor SR-BI is critical for its sensitivity to a small-molecule inhibitor and normal lipid transport activity. Proc Natl Acad Sci U S A 2011; 108:12243-8. [PMID: 21746906 DOI: 10.1073/pnas.1109078108] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The HDL receptor, scavenger receptor, class B, type I (SR-BI), is a homooligomeric cell surface glycoprotein that controls HDL structure and metabolism by mediating the cellular selective uptake of lipids, mainly cholesteryl esters, from HDL. The mechanism underlying SR-BI-mediated lipid transfer, which differs from classic receptor-mediated endocytosis, involves a two-step process (binding followed by lipid transport) that is poorly understood. Our previous structure/activity analysis of the small-molecule inhibitor blocker of lipid transport 1 (BLT-1), which potently (IC(50) ∼ 50 nM) blocks SR-BI-mediated lipid transport, established that the sulfur in BLT-1's thiosemicarbazone moiety was essential for activity. Here we show that BLT-1 is an irreversible inhibitor of SR-BI, raising the possibility that cysteine(s) in SR-BI interact with BLT-1. Mass spectrometric analysis of purified SR-BI showed two of its six exoplasmic cysteines have free thiol groups (Cys251 and Cys384). Converting Cys384 (but not Cys251) to serine resulted in complete BLT-1 insensitivity, establishing that the unique molecular target of BLT-1 inhibition of cellular SR-BI dependent lipid transport is SR-BI itself. The C384S substitution reduced the receptor's intrinsic lipid uptake activity by approximately 60% without dramatically altering its surface expression, homooligomerization, or HDL binding. Thus, a small-molecule screening approach identified a key residue in SR-BI involved in lipid transport, providing a powerful springboard into the analyses of the structure and mechanism of SR-BI, and highlighting the power of this approach for such analyses.
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29
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Papale GA, Hanson PJ, Sahoo D. Extracellular disulfide bonds support scavenger receptor class B type I-mediated cholesterol transport. Biochemistry 2011; 50:6245-54. [PMID: 21675794 DOI: 10.1021/bi2005625] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Scavenger receptor class B type I (SR-BI) binds high-density lipoprotein (HDL) and mediates the selective uptake of cholesteryl esters (CE). Although the extracellular domain of SR-BI is critical for function, the structural characteristics of this region remain elusive. Using sulfhydryl labeling strategies, we report the novel finding that all six cysteine (Cys) residues in the extracellular domain of SR-BI are involved in disulfide bond formation that is intramolecular by nature. We hypothesized that an SR-BI conformation stabilized by extracellular disulfide bonds is a prerequisite for SR-BI-mediated cholesterol transport. Thus, single-Cys mutant SR-BI receptors (C251S-, C280S-, C321S-, C323S-, C334S-, and C384S-SR-BI), as well as Cys-less SR-BI, a mutant SR-BI receptor void of all Cys residues, were created, and plasma membrane localization was confirmed. Functional assays revealed that C280S-, C321S-, C323S-, and C334S-SR-BI and Cys-less SR-BI mutant receptors displayed weakened HDL binding and subsequent selective uptake of HDL-CE. However, only C323S-SR-BI and Cys-less SR-BI were unable to mediate wild-type levels of efflux of free cholesterol (FC) to HDL. None of the Cys mutations disrupted SR-BI's ability to redistribute plasma membrane FC. Taken together, the intramolecular disulfide bonds in the extracellular domain of SR-BI appear to maintain the receptor in a conformation integral to its cholesterol transport functions.
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Affiliation(s)
- Gabriella A Papale
- Department of Medicine, Division of Endocrinology, Metabolism and Clinical Nutrition, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
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30
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Gaidukov L, Nager AR, Xu S, Penman M, Krieger M. Glycine dimerization motif in the N-terminal transmembrane domain of the high density lipoprotein receptor SR-BI required for normal receptor oligomerization and lipid transport. J Biol Chem 2011; 286:18452-64. [PMID: 21454587 PMCID: PMC3099662 DOI: 10.1074/jbc.m111.229872] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Revised: 03/23/2011] [Indexed: 12/15/2022] Open
Abstract
Scavenger receptor class B, type I (SR-BI), a CD36 superfamily member, is an oligomeric high density lipoprotein (HDL) receptor that mediates negatively cooperative HDL binding and selective lipid uptake. We identified in the N-terminal transmembrane (N-TM) domain of SR-BI a conserved glycine dimerization motif, G(15)X(2)G(18)X(3)AX(2)G(25), of which the submotif G(18)X(3)AX(2)G(25) significantly contributes to homodimerization and lipid uptake activity. SR-BI variants were generated by mutations (single or multiple Gly → Leu substitutions) or by replacing the N-TM domain with those from other CD36 superfamily members containing (croquemort) or lacking (lysosomal integral membrane protein (LIMP) II) this glycine motif (chimeras). None of the SR-BI variants exhibited altered surface expression (based on antibody binding) or HDL binding. However, the G15L/G18L/G25L triple mutant exhibited reductions in cell surface homo-oligomerization (>10-fold) and the rate of selective lipid uptake (∼ 2-fold). Gly(18) and Gly(25) were necessary for normal lipid uptake activity of SR-BI and the SR-BI/croquemort chimera. The lipid uptake activity of the glycine motif-deficient SR-BI/LIMP II chimera was low but could be increased by introducing glycines at positions 18 and 25. The rate of lipid uptake mediated by SR-BI/LIMP II chimeras was proportional to the extent of receptor oligomerization. Thus, the glycine dimerization motif G(18)X(3)AX(2)G(25) in the N-TM domain of SR-BI contributes substantially to the homo-oligomerization and lipid transport activity of SR-BI but does not influence the negative cooperativity of HDL binding. Oligomerization-independent binding cooperativity suggests that classic allostery is not involved and that the negative cooperativity is probably the consequence of a "lattice effect" (interligand steric interference accompanying binding to adjacent receptors).
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Affiliation(s)
- Leonid Gaidukov
- From the Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Andrew R. Nager
- From the Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Shangzhe Xu
- From the Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Marsha Penman
- From the Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Monty Krieger
- From the Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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Nieland TJ, Xu S, Penman M, Krieger M. Negatively cooperative binding of high-density lipoprotein to the HDL receptor SR-BI. Biochemistry 2011; 50:1818-30. [PMID: 21254782 PMCID: PMC3065119 DOI: 10.1021/bi101657j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Scavenger receptor class B, type I (SR-BI), is a high-density lipoprotein (HDL) receptor, which also binds low-density lipoprotein (LDL), and mediates the cellular selective uptake of cholesteryl esters from lipoproteins. SR-BI also is a coreceptor for hepatitis C virus and a signaling receptor that regulates cell metabolism. Many investigators have reported that lipoproteins bind to SR-BI via a single class of independent (not interacting), high-affinity binding sites (one site model). We have reinvestigated the ligand concentration dependence of (125)I-HDL binding to SR-BI and SR-BI-mediated specific uptake of [(3)H]CE from [(3)H]CE-HDL using an expanded range of ligand concentrations (<1 μg of protein/mL, lower than previously reported). Scatchard and nonlinear least-squares model fitting analyses of the binding and uptake data were both inconsistent with a single class of independent binding sites binding univalent lipoprotein ligands. The data are best fit by models in which SR-BI has either two independent classes of binding sites or one class of sites exhibiting negative cooperativity due to either classic allostery or ensemble effects ("lattice model"). Similar results were observed for LDL. Application of the "infinite dilution" dissociation rate method established that the binding of (125)I-HDL to SR-BI at 4 °C exhibits negative cooperativity. The unexpected complexity of the interactions of lipoproteins with SR-BI should be taken into account when interpreting the results of experiments that explore the mechanism(s) by which SR-BI mediates ligand binding, lipid transport, and cell signaling.
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Affiliation(s)
- Thomas J.F. Nieland
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, MA 02139
- Broad Institute of Harvard and MIT, 7 Cambridge Center, Cambridge, MA 02142
| | - Shangzhe Xu
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, MA 02139
| | - Marsha Penman
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, MA 02139
| | - Monty Krieger
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, MA 02139
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Fioravanti J, Medina-Echeverz J, Berraondo P. Scavenger receptor class B, type I: a promising immunotherapy target. Immunotherapy 2011; 3:395-406. [DOI: 10.2217/imt.10.104] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Scavenger receptor class B, type I (SR-BI) is a crucial molecule in lipid metabolism, since the interaction of high-density lipoproteins (HDLs) with SR-BI is involved in reverse cholesterol transport and cholesterol efflux. Recent findings also underscore a critical role of SR-BI in antimicrobial and immune responses. SR-BI is not only highly expressed in liver and steroidogenic glands, but also in endothelial cells, macrophages and dendritic cells. SR-BI mainly mediates anti-inflammatory responses, which may be altered by dysfunctional HDLs produced in several diseases. Moreover, SR-BI has been involved in the capture and cross-presentation of antigens from viruses, bacteria and parasites. It thus works as a pattern-recognition receptor that interacts with both damage-associated molecular patterns and pathogen-associated molecular patterns. These new findings in the microbiology and immunology fields present SR-BI as an unexplored therapeutic target that warrants further basic and applied research.
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Affiliation(s)
- Jessica Fioravanti
- Division of Hepatology & Gene Therapy, Center for Applied Medical Research, University of Navarra, Pamplona, Navarra, Spain
| | - José Medina-Echeverz
- Division of Hepatology & Gene Therapy, Center for Applied Medical Research, University of Navarra, Pamplona, Navarra, Spain
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Nieland TJF, Xu S, Penman M, Krieger M. Negatively cooperative binding of high-density lipoprotein to the HDL receptor SR-BI. Biochemistry 2011. [PMID: 21254782 DOI: 10.1021/bi1011657j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Scavenger receptor class B, type I (SR-BI), is a high-density lipoprotein (HDL) receptor, which also binds low-density lipoprotein (LDL), and mediates the cellular selective uptake of cholesteryl esters from lipoproteins. SR-BI also is a coreceptor for hepatitis C virus and a signaling receptor that regulates cell metabolism. Many investigators have reported that lipoproteins bind to SR-BI via a single class of independent (not interacting), high-affinity binding sites (one site model). We have reinvestigated the ligand concentration dependence of (125)I-HDL binding to SR-BI and SR-BI-mediated specific uptake of [(3)H]CE from [(3)H]CE-HDL using an expanded range of ligand concentrations (<1 μg of protein/mL, lower than previously reported). Scatchard and nonlinear least-squares model fitting analyses of the binding and uptake data were both inconsistent with a single class of independent binding sites binding univalent lipoprotein ligands. The data are best fit by models in which SR-BI has either two independent classes of binding sites or one class of sites exhibiting negative cooperativity due to either classic allostery or ensemble effects ("lattice model"). Similar results were observed for LDL. Application of the "infinite dilution" dissociation rate method established that the binding of (125)I-HDL to SR-BI at 4 °C exhibits negative cooperativity. The unexpected complexity of the interactions of lipoproteins with SR-BI should be taken into account when interpreting the results of experiments that explore the mechanism(s) by which SR-BI mediates ligand binding, lipid transport, and cell signaling.
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Affiliation(s)
- Thomas J F Nieland
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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Zhang X, Chen B. Recombinant high density lipoprotein reconstituted with apolipoprotein AI cysteine mutants as delivery vehicles for 10-hydroxycamptothecin. Cancer Lett 2010; 298:26-33. [DOI: 10.1016/j.canlet.2010.05.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 05/27/2010] [Accepted: 05/31/2010] [Indexed: 10/19/2022]
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Murakami T, Wijagkanalan W, Hashida M, Tsuchida K. Intracellular drug delivery by genetically engineered high-density lipoprotein nanoparticles. Nanomedicine (Lond) 2010; 5:867-79. [DOI: 10.2217/nnm.10.66] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Aim: Nascent high-density lipoprotein (HDL) capable of intracellularly delivering anticancer drugs was developed to potentiate antitumor activities. Materials & methods: Apolipoprotein A-I, a major component protein of HDL, was genetically fused to TAT peptide, a protein transduction domain. Nascent HDL was prepared with this mutant and phospholipids. Results & discussion: Intracellular delivery of doxorubicin (DXR) by TAT-fused HDL was confirmed by confocal microscopy. Treatment of cancer cells with TAT-fused HDL–DXR complex resulted in enhanced growth inhibition. Furthermore, TAT-fused HDL–DXR complex suppressed tumor growth in mice more efficiently than HDL–DXR complex. No bodyweight loss was observed for the TAT complex. These results clearly demonstrate the usefulness of TAT fusion to nascent HDL to potentiate the antitumor activity of DXR. Conclusion: The genetic fusion of apoA-I with biologically active peptides potentially enables a simple assembly of biocompatible and versatile drug carriers.
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Affiliation(s)
- Tatsuya Murakami
- Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi 470–1192, Japan
- PRESTO, JST, 4–1-8 Honcho Kawaguchi, Saitama 332–0012, Japan
- Institute for Integrated Cell-Material Sciences, Kyoto University, Sakyo-ku, Kyoto 606–8304, Japan
| | - Wassana Wijagkanalan
- Department of Drug Delivery Research, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606–8501, Japan
| | - Mitsuru Hashida
- Institute for Integrated Cell-Material Sciences, Kyoto University, Sakyo-ku, Kyoto 606–8304, Japan
- Department of Drug Delivery Research, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606–8501, Japan
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Extracellular hydrophobic regions in scavenger receptor BI play a key role in mediating HDL-cholesterol transport. Arch Biochem Biophys 2010; 496:132-9. [PMID: 20219439 DOI: 10.1016/j.abb.2010.02.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 02/18/2010] [Accepted: 02/23/2010] [Indexed: 01/26/2023]
Abstract
The binding of high density lipoprotein (HDL) to scavenger receptor BI (SR-BI) is responsible for whole-body cholesterol disposal via reverse cholesterol transport. The extracellular domain of SR-BI is required for HDL binding and selective uptake of HDL-cholesterol. We identified six highly hydrophobic regions in this domain that may be important for receptor activity and performed site-directed mutagenesis to investigate the importance of these regions in SR-BI-mediated cholesterol transport. Non-conservative mutation of the regions encompassing V67, L140/L142, V164 or V221 reduced hydrophobicity and impaired the ability of SR-BI to bind HDL, mediate selective uptake of HDL-cholesterol, promote cholesterol efflux, and enlarge the cholesterol oxidase-sensitive pool of membrane free cholesterol. In contrast, conservative mutations at V67, V164 or V221 did not affect the hydrophobicity or these cholesterol transport activities. We conclude that the hydrophobicity of N-terminal extracellular regions of SR-BI is critical for cholesterol transport, possibly by mediating receptor-ligand and/or receptor-membrane interactions.
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Abstract
Dysregulation of cholesterol balance contributes significantly to atherosclerotic cardiovascular disease (ASCVD), the leading cause of death in the United States. The intestine has the unique capability to act as a gatekeeper for entry of cholesterol into the body, and inhibition of intestinal cholesterol absorption is now widely regarded as an attractive non-statin therapeutic strategy for ASCVD prevention. In this chapter we discuss the current state of knowledge regarding sterol transport across the intestinal brush border membrane. The purpose of this work is to summarize substantial progress made in the last decade in regards to protein-mediated sterol trafficking, and to discuss this in the context of human disease.
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Affiliation(s)
| | - Liqing Yu
- Address correspondence to: Liqing Yu, M.D., Ph.D., Department of Pathology Section on Lipid Sciences, Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157-1040, Tel: 336-716-0920, Fax: 336-716-6279,
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Abstract
High density lipoprotein (HDL) possesses important anti-atherogenic properties and this review addresses the molecular mechanisms underlying these functions. The structures and cholesterol transport abilities of HDL particles are determined by the properties of their exchangeable apolipoprotein (apo) components. ApoA-I and apoE, which are the best characterized in structural terms, contain a series of amphipathic alpha-helical repeats. The helices located in the amino-terminal two-thirds of the molecule adopt a helix bundle structure while the carboxy-terminal segment forms a separately folded, relatively disorganized, domain. The latter domain initiates lipid binding and this interaction induces changes in conformation; the alpha-helix content increases and the amino-terminal helix bundle can open subsequently. These conformational changes alter the abilities of apoA-I and apoE to function as ligands for their receptors. The apoA-I and apoE molecules possess detergent-like properties and they can solubilize vesicular phospholipid to create discoidal HDL particles with hydrodynamic diameters of ~10 nm. In the case of apoA-I, such a particle is stabilized by two protein molecules arranged in an anti-parallel, double-belt, conformation around the edge of the disc. The abilities of apoA-I and apoE to solubilize phospholipid and stabilize HDL particles enable these proteins to be partners with ABCA1 in mediating efflux of cellular phospholipid and cholesterol, and the biogenesis of HDL particles. ApoA-I-containing nascent HDL particles play a critical role in cholesterol transport in the circulation whereas apoE-containing HDL particles mediate cholesterol transport in the brain. The mechanisms by which HDL particles are remodeled by lipases and lipid transfer proteins, and interact with SR-BI to deliver cholesterol to cells, are reviewed.
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de Beer MC, Webb NR, Whitaker NL, Wroblewski JM, Jahangiri A, van der Westhuyzen DR, de Beer FC. SR-BI selective lipid uptake: subsequent metabolism of acute phase HDL. Arterioscler Thromb Vasc Biol 2009; 29:1298-303. [PMID: 19304574 DOI: 10.1161/atvbaha.109.186502] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The purpose of this study was to investigate the interaction of SAA and SR-BI in remodeling of acute phase HDL (AP HDL). METHODS AND RESULTS We used SAA and SR-BI adenoviral vector expression models to study the interaction between these entities. SR-BI processing of mouse AP HDL generated progressively smaller discreet HDL particles with distinct apolipoprotein compositions. SR-BI actions segregated apolipoproteins with the smallest particles containing only apoA-I. Larger remnants contained apoA-I, apoA-II, and SAA. Small apoA-I only particles failed to associate with preformed HDL, whereas larger remnants readily did. The presence of SAA on SR-BI-processed HDL particles propelled apoA-I to a small lipid-poor form and accelerated apoA-I catabolism. CONCLUSIONS Data indicate that after core and surface HDL lipid perturbation by SR-BI, SAA propels apoA-I to a small lipid-poor form while accelerating HDL metabolism.
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Affiliation(s)
- Maria C de Beer
- Graduate Center for Nutritional Science, University of Kentucky Medical Center, Lexington, USA.
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40
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Shimizu H, Oh-I S, Hashimoto K, Nakata M, Yamamoto S, Yoshida N, Eguchi H, Kato I, Inoue K, Satoh T, Okada S, Yamada M, Yada T, Mori M. Peripheral administration of nesfatin-1 reduces food intake in mice: the leptin-independent mechanism. Endocrinology 2009; 150:662-71. [PMID: 19176321 DOI: 10.1210/en.2008-0598] [Citation(s) in RCA: 232] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Nesfatin-1 is a novel satiety molecule in the hypothalamus and is also present in peripheral tissues. Here we sought to identify the active segment of nesfatin-1 and to determine the mechanisms of its action after peripheral administration in mice. Intraperitoneal injection of nesfatin-1 suppressed food intake in a dose-dependent manner. Nesfatin-1 has three distinct segments; we tested the effect of each segment on food intake. Injection of the midsegment decreased food intake under leptin-resistant conditions such as db/db mice and mice fed a high-fat diet. After injection of the midsegment, expression of c-Fos was significantly activated in the brainstem nucleus tractus solitarius (NTS) but not in the hypothalamic arcuate nucleus; the nicotinic cholinergic pathway to the NTS contributed to midsegment-induced anorexia. Midsegment injection significantly increased expression of proopiomelanocortin and cocaine- and amphetamine-regulated transcript genes in the NTS but not in the arcuate nucleus. Investigation of mutant midsegments demonstrated that a region with amino acid sequence similarity to the active site of agouti-related peptide was indispensable for anorexigenic induction. Our findings indicate that the midsegment of nesfatin-1 causes anorexia, possibly by activating POMC and CART neurons in the NTS via a leptin-independent mechanism after peripheral stimulation.
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Affiliation(s)
- H Shimizu
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Japan.
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Gangabadage CS, Zdunek J, Tessari M, Nilsson S, Olivecrona G, Wijmenga SS. Structure and Dynamics of Human Apolipoprotein CIII. J Biol Chem 2008; 283:17416-27. [DOI: 10.1074/jbc.m800756200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Komori H, Arai H, Kashima T, Huby T, Kita T, Ueda Y. Coexpression of CLA-1 and human PDZK1 in murine liver modulates HDL cholesterol metabolism. Arterioscler Thromb Vasc Biol 2008; 28:1298-303. [PMID: 18403724 DOI: 10.1161/atvbaha.108.165845] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE In rodents scavenger receptor class B type I (SR-BI) is a key molecule for selective uptake of cholesteryl ester from high-density lipoprotein (HDL). This study was aimed to clarify the role of the human SR-BI/CD36 and LIMP-II Analogues-1 (CLA-1) as a molecular target of selective uptake of cholesteryl ester from HDL in vivo. METHODS AND RESULTS To clarify the function and regulation of CLA-1 in vivo we produced CLA-1 BAC transgenic mice. In spite of abundant hepatic RNA expression of CLA-1, CLA-1 BAC transgenic mice had no significant effect on mouse HDL cholesterol. Although coexpression of a human scaffolding protein PDZK1 along with CLA-1 enhanced hepatic CLA-1 expression, it did not affect mouse HDL cholesterol levels, either. However, in the presence of human apoA-1, HDL cholesterol level and size were significantly reduced in CLA-1 transgenic mice, and its reduction was more pronounced in CLA-1/human PDZK1 double transgenic mouse. CONCLUSIONS We established a mouse model to study human reverse cholesterol transport by expressing CLA-1, human PDZK1, and human apoA-I gene. Our results imply that enhancing CLA-1 expression by human PDZK1 in the liver can modulate HDL cholesterol metabolism and possibly enhance reverse cholesterol transport to prevent the progression of atherosclerosis in human.
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Affiliation(s)
- Hidenori Komori
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
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43
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Macrophage scavenger receptors and host-derived ligands. Methods 2008; 43:207-17. [PMID: 17920517 DOI: 10.1016/j.ymeth.2007.06.004] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Accepted: 06/25/2007] [Indexed: 02/07/2023] Open
Abstract
The scavenger receptors are a large family of molecules that are structurally diverse and have been implicated in a range of functions. They are expressed by myeloid cells, selected endothelial cells and some epithelial cells and recognise many different ligands, including microbial pathogens as well as endogenous and modified host-derived molecules. This review will focus on the eight classes of scavenger receptors (class A-H) in terms of their structure, expression and recognition of host-derived ligands. Scavenger receptors have been implicated in a range of physiological and pathological processes, such as atherosclerosis and Alzheimer's disease, and function in adhesion and tissue maintenance. More recently, some of the scavenger receptors have been shown to mediate binding and endocytosis of chaperone proteins, such as the heat shock proteins, thereby playing an important role in antigen cross-presentation.
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Van Eck M, Hoekstra M, Out R, Bos IST, Kruijt JK, Hildebrand RB, Van Berkel TJC. Scavenger receptor BI facilitates the metabolism of VLDL lipoproteins in vivo. J Lipid Res 2007; 49:136-46. [PMID: 17954936 DOI: 10.1194/jlr.m700355-jlr200] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Scavenger receptor class B type I (SR-BI) functions as an HDL receptor that promotes the selective uptake of cholesteryl esters (CEs). The physiological role of SR-BI in VLDL metabolism, however, is largely unknown. SR-BI deficiency resulted in elevated VLDL cholesterol levels, both on chow diet and upon challenge with high-cholesterol diets. To specifically elucidate the role of SR-BI in VLDL metabolism, the plasma clearance and hepatic uptake of (125)I-beta-VLDL were studied in SR-BI(+/+) and SR-BI(-/-) mice. At 20 min after injection, 66 +/- 2% of the injected dose was taken up by the liver in SR-BI(+/+) mice, as compared with only 22 +/- 4% (P = 0.0007) in SR-BI(-/-) mice. In vitro studies established that the B(max) of (125)I-beta-VLDL binding was reduced from 469 +/- 30 ng/mg in SR-BI(+/+) hepatocytes to 305 +/- 20 ng/mg (P = 0.01) in SR-BI(-/-) hepatocytes. Both in vivo and in vitro, limited to no selective uptake of CEs from beta-VLDL was found. Interestingly, HDL effectively competed for the association of beta-VLDL in the presence as well as in the absence of SR-BI, indicating a second common recognition site. In conclusion, SR-BI plays an important physiological role in the metabolism of VLDL (remnants).
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Affiliation(s)
- Miranda Van Eck
- Divison of Biopharmaceutics, Leiden/Amsterdam Center for Drug Research, Gorlaeus Laboratories, Leiden University, Leiden, The Netherlands.
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45
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Kim SI, Shin D, Choi TH, Lee JC, Cheon GJ, Kim KY, Park M, Kim M. Systemic and specific delivery of small interfering RNAs to the liver mediated by apolipoprotein A-I. Mol Ther 2007; 15:1145-52. [PMID: 17440441 DOI: 10.1038/sj.mt.6300168] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Tissue-targeted delivery of small interfering RNA (siRNA) must be achieved before RNA interference (RNAi) technology can be used in practical therapeutic approaches. In this study, the potential of apolipoprotein A-I (apo A-I) for the systemic delivery of nucleic acids to the liver is demonstrated using real-time in vivo imaging. As a proof of concept, synthetic siRNAs against hepatitis B virus (HBV) were formulated into complexes of apo A-I and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)/cholesterol (DTC-Apo) and injected intravenously (i.v.) into a mouse model carrying replicating HBV. We show that administration of these nanoparticles can significantly reduce viral protein expression by receptor-mediated endocytosis. The advantages of the apo A-I-mediated siRNA delivery method are its liver specificity, its effectiveness at low doses (< or = 2 mg/kg) in only a single treatment, and its persistent antiviral effect up to 8 days. The liver-targeted gene silencing was also shown by in vivo images, in which bioluminescent signals emitted from the liver were efficiently reduced after i.v. administration of luciferase-specific siRNA and DTC-Apo lipoplex. Thus, our unique approach to siRNA delivery creates a foundation for the development of a new class of promising therapeutics against hepatitis viruses or hepatocyte genes related to tumor growth.
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Affiliation(s)
- Soo In Kim
- Immunology and Virology Group, Mogam Biotechnology Research Institute, Yongin-si, South Korea
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46
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Warnick GR, McNamara JR, Boggess CN, Clendenen F, Williams PT, Landolt CC. Polyacrylamide gradient gel electrophoresis of lipoprotein subclasses. Clin Lab Med 2007; 26:803-46. [PMID: 17110241 DOI: 10.1016/j.cll.2006.07.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
High-density (HDL), low-density (LDL), and very-low-density (VLDL) lipoproteins are heterogeneous cholesterol-containing particles that differ in their metabolism, environmental interactions, and association with disease. Several protocols use polyacrylamide gradient gel electrophoresis (GGE) to separate these major lipoproteins into known subclasses. This article provides a brief history of the discovery of lipoprotein heterogeneity and an overview of relevant lipoprotein metabolism, highlighting the importance of the subclasses in the context of their metabolic origins, fates, and clinical implications. Various techniques using polyacrylamide GGE to assess HDL and LDL heterogeneity are described, and how the genetic and environmental determinations of HDL and LDL affect lipoprotein size heterogeneity and the implications for cardiovascular disease are outlined.
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Affiliation(s)
- G Russell Warnick
- Berkeley HeartLab Inc., 960 Atlantic Avenue, Suite 100 Alameda, CA 94501, USA.
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47
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Chiu PCN, Chung MK, Koistinen R, Koistinen H, Seppala M, Ho PC, Ng EHY, Lee KF, Yeung WSB. Glycodelin-A interacts with fucosyltransferase on human sperm plasma membrane to inhibit spermatozoa-zona pellucida binding. J Cell Sci 2007; 120:33-44. [PMID: 17148576 DOI: 10.1242/jcs.03258] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fertilization depends on successful binding of the spermatozoa to the zona pellucida of the oocyte. Glycodelin-A inhibits spermatozoa-zona pellucida binding. Previous data showed that glycodelin-A receptor(s) and zona pellucida protein receptor(s) on human spermatozoa are closely related. Using a chemical cross-linking approach, the glycodelin-A-sperm receptor complex was isolated. The receptor was identified to be fucosyltransferase-5 (FUT5) by mass spectrometry and confirmed with the use of anti-FUT5 antibodies. Sperm FUT5 was an externally oriented integral membrane protein in the acrosomal region of human spermatozoa. Biologically active FUT5 was purified from spermatozoa. Co-immunoprecipitation confirmed the interaction between glycodelin-A and sperm FUT5. Solubilized zona pellucida reduced the binding of glycodelin-A to sperm FUT5. An anti-FUT5 antibody and FUT5 acceptor blocked the binding of glycodelin-A to spermatozoa and the zona binding inhibitory activity of glycodelin-A. Sperm FUT5 bound strongly to intact and solubilized human zona pellucida. The equilibrium dissociation constant of sperm FUT5 binding to solubilized zona pellucida was 42.82 pmol/ml. These observations suggest that human sperm FUT5 is a receptor of glycodelin-A and zona pellucida proteins, and that glycodelin-A inhibits spermatozoa-zona binding by blocking the binding of sperm FUT5 to the zona pellucida.
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Affiliation(s)
- Philip C N Chiu
- Department of Obstetrics and Gynaecology, University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Hong Kong, China
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48
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Vishnyakova TG, Kurlander R, Bocharov AV, Baranova IN, Chen Z, Abu-Asab MS, Tsokos M, Malide D, Basso F, Remaley A, Csako G, Eggerman TL, Patterson AP. CLA-1 and its splicing variant CLA-2 mediate bacterial adhesion and cytosolic bacterial invasion in mammalian cells. Proc Natl Acad Sci U S A 2006; 103:16888-93. [PMID: 17071747 PMCID: PMC1636549 DOI: 10.1073/pnas.0602126103] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Indexed: 11/18/2022] Open
Abstract
CD36 and LIMPII analog 1, CLA-1, and its splicing variant, CLA-2 (SR-BI and SR-BII in rodents), are human high density lipoprotein receptors with an identical extracellular domain which binds a spectrum of ligands including bacterial cell wall components. In this study, CLA-1- and CLA-2-stably transfected HeLa and HEK293 cells demonstrated several-fold increases in the uptake of various bacteria over mock-transfected cells. All bacteria tested, including both Gram-negatives (Escherichia coli K12, K1 and Salmonella typhimurium) and Gram-positives (Staphylococcus aureus and Listeria monocytogenes), demonstrated various degrees of lower uptake in control cells. This result is consistent with the presence of high-density lipoprotein-receptor-independent bacterial uptake that is enhanced by CLA-1/CLA-2 overexpression. Bacterial lipopolysaccharides, lipoteichoic acid, and synthetic amphipathic helical peptides (L-37pA and D-37pA) competed with E. coli K12 for CLA-1 and CLA-2 binding. Transmission electron microscopy and confocal microscopy revealed cytosolic accumulation of bacteria in CLA-1/CLA-2-overexpressing HeLa cells. The antibiotic protection assay confirmed that E. coli K12 was able to survive and replicate intracellularly in CLA-1- and CLA-2-overexpressing HeLa, but both L-37pA and D-37pA prevented E. coli K12 invasion. Peritoneal macrophages isolated from SR-BI/BII-knockout mice demonstrated a 30% decrease in bacterial uptake when compared with macrophages from normal mice. Knockout macrophages were also characterized by decreased bacterial cytosolic invasion, ubiquitination, and proteasome mobilization while retaining bacterial lysosomal accumulation. These results indicate that, by facilitating bacterial adhesion and cytosolic invasion, CLA-1 and CLA-2 may play an important role in infection and sepsis.
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Affiliation(s)
| | | | | | | | | | | | | | - Daniela Malide
- Light Microscopy Core Facility, National Heart, Lung, and Blood Institute
| | | | | | - Gyorgy Csako
- Department of Laboratory Medicine, Clinical Center
| | - Thomas L. Eggerman
- Division of Diabetes, Endocrinology, and Metabolic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
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49
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Kleveland EJ, Syvertsen BL, Ruyter B, Vegusdal A, Jørgensen SM, Gjøen T. Characterization of scavenger receptor class B, type I in Atlantic salmon (Salmo salar L.). Lipids 2006; 41:1017-27. [PMID: 17263301 DOI: 10.1007/s11745-006-5052-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The scavenger receptor class B, type I (SR-BI) is an important player in regulation of mammalian lipid homeostasis. We therefore wanted to study this receptor in Atlantic salmon (Salmo salar L.), which requires a diet with particular high lipid content. We have for the first time cloned and characterized SR-BI from a salmonid fish. The predicted 494 amino acid protein contained two transmembrane domains, several putative N-glycosylation sites, and showed 72% sequence identity with the predicted homolog from zebrafish. SR-BI expression was analyzed by reverse transcription Real-Time PCR in several tissues, and a high relative expression in salmon midgut was detected, which may suggest that SR-BI has a role in uptake of lipids from the diet. We also expressed a construct of salmon myc-tagged SR-BI in salmon TO cells and HeLa cells, which gave a protein of approximately 80 kDa on reducing SDS-PAGE using an antibody against the myc-epitope. Immunofluorescence microscopy analyses of the salmon SR-BI protein in transiently transfected HeLa cells revealed staining in the cell periphery and in some intracellular membranes, but not in the nucleus, which indicated that the salmon protein may be a functional membrane protein. We also observed a high degree of co-localization using an anti-peptide SR-BI antiserum. We found that 20 microg mL(-1) insulin up-regulated the SR-BI mRNA levels in primary cultures of salmon hepatocytes relative to untreated cells. Oleic acid, EPA, DHA, or dexamethasone did not affect the relative expression of SR-BI in this liver model system. In conclusion, the salmon SR-BI cDNA encoded a protein with several features common to those of mammalian species. SR-BI gene expression was high in the intestine, which leads us to propose that SR-BI may contribute to the uptake of lipids from the diet.
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Affiliation(s)
- E J Kleveland
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
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50
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Gupta N, Manevich Y, Kazi AS, Tao JQ, Fisher AB, Bates SR. Identification and characterization of p63 (CKAP4/ERGIC-63/CLIMP-63), a surfactant protein A binding protein, on type II pneumocytes. Am J Physiol Lung Cell Mol Physiol 2006; 291:L436-46. [PMID: 16556726 DOI: 10.1152/ajplung.00415.2005] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Surfactant protein A (SP-A) binds to alveolar type II cells through a specific high-affinity cell membrane receptor, although the molecular nature of this receptor is unclear. In the present study, we have identified and characterized an SP-A cell surface binding protein by utilizing two chemical cross-linkers: profound sulfo-SBED protein-protein interaction reagent and dithiobis(succinimidylpropionate) (DSP). Sulfo-SBED-biotinylated SP-A was cross-linked to the plasma membranes isolated from rat type II cells, and the biotin label was transferred from SP-A to its receptor by reduction. The biotinylated SP-A-binding protein was identified on blots by using streptavidin-labeled horseradish peroxidase. By using DSP, we cross-linked SP-A to intact mouse type II cells and immunoprecipitated the SP-A-receptor complex using anti-SP-A antibody. Both of the cross-linking approaches showed a major band of 63 kDa under reduced conditions that was identified as the rat homolog of the human type II transmembrane protein p63 (CKAP4/ERGIC-63/CLIMP-63) by matrix-assisted laser desorption ionization and nanoelectrospray tandem mass spectrometry of tryptic fragments. Thereafter, we confirmed the presence of p63 protein in the cross-linked SP-A-receptor complex by immunoprobing with p63 antibody. Coimmunoprecipitation experiments and functional assays confirmed specific interaction between SP-A and p63. Antibody to p63 could block SP-A-mediated inhibition of ATP-stimulated phospholipid secretion. Both intracellular and membrane localized pools of p63 were detected on type II cells by immunofluorescence and immunobloting. p63 colocalized with SP-A in early endosomes. Thus p63 closely interacts with SP-A and may play a role in the trafficking or the biological function of the surfactant protein.
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Affiliation(s)
- Nisha Gupta
- Institute for Environmental Medicine, University of Pennsylvania School of Medicine, Philadelphia, 19104, USA
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