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Bassila C, Kluck GEG, Thyagarajan N, Chathely KM, Gonzalez L, Trigatti BL. Ligand-dependent interactions between SR-B1 and S1PR1 in macrophages and atherosclerotic plaques. J Lipid Res 2024; 65:100541. [PMID: 38583587 PMCID: PMC11087725 DOI: 10.1016/j.jlr.2024.100541] [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: 08/07/2023] [Revised: 03/16/2024] [Accepted: 04/01/2024] [Indexed: 04/09/2024] Open
Abstract
HDLs carry sphingosine-1-phosphate (S1P) and stimulate signaling pathways in different cells including macrophages and endothelial cells, involved in atherosclerotic plaque development. HDL signaling via S1P relies on the HDL receptor scavenger receptor class B, type I (SR-B1) and the sphingosine-1-phosphate receptor 1 (S1PR1), which interact when both are heterologously overexpressed in the HEK293 cell line. In this study, we set out to test if SR-B1 and S1PR1 interacted in primary murine macrophages in culture and atherosclerotic plaques. We used knock-in mice that endogenously expressed S1PR1 tagged with eGFP-(S1pr1eGFP/eGFP mice), combined with proximity ligation analysis to demonstrate that HDL stimulates the physical interaction between SR-B1 and S1PR1 in primary macrophages, that this is dependent on HDL-associated S1P and can be blocked by an inhibitor of SR-B1's lipid transfer activity or an antagonist of S1PR1. We also demonstrate that a synthetic S1PR1-selective agonist, SEW2871, stimulates the interaction between SR-B1 and S1PR1 and that this was also blocked by an inhibitor of SR-B1's lipid transport activity. Furthermore, we detected abundant SR-B1/S1PR1 complexes in atherosclerotic plaques of S1pr1eGFP/eGFP mice that also lacked apolipoprotein E. Treatment of mice with the S1PR1 antagonist, Ex26, for 12 h disrupted the SR-B1-S1PR1 interaction in atherosclerotic plaques. These findings demonstrate that SR-B1 and S1PR1 form ligand-dependent complexes both in cultured primary macrophages and within atherosclerotic plaques in mice and provide mechanistic insight into how SR-B1 and S1PR1 participate in mediating HDL signaling to activate atheroprotective responses in macrophages.
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Affiliation(s)
- Christine Bassila
- Department of Biochemistry and Biomedical Sciences, Thrombosis and Atherosclerosis Research Institute, Hamilton Health Sciences, McMaster University, Hamilton, ON, Canada
| | - George E G Kluck
- Department of Biochemistry and Biomedical Sciences, Thrombosis and Atherosclerosis Research Institute, Hamilton Health Sciences, McMaster University, Hamilton, ON, Canada
| | - Narmadaa Thyagarajan
- Department of Biochemistry and Biomedical Sciences, Thrombosis and Atherosclerosis Research Institute, Hamilton Health Sciences, McMaster University, Hamilton, ON, Canada
| | - Kevin M Chathely
- Department of Biochemistry and Biomedical Sciences, Thrombosis and Atherosclerosis Research Institute, Hamilton Health Sciences, McMaster University, Hamilton, ON, Canada
| | - Leticia Gonzalez
- Department of Biochemistry and Biomedical Sciences, Thrombosis and Atherosclerosis Research Institute, Hamilton Health Sciences, McMaster University, Hamilton, ON, Canada
| | - Bernardo L Trigatti
- Department of Biochemistry and Biomedical Sciences, Thrombosis and Atherosclerosis Research Institute, Hamilton Health Sciences, McMaster University, Hamilton, ON, Canada.
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2
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Sabnis N, Raut S, Nagarajan B, Kapic A, Dossou AS, Lothstein L, Fudala R, Bunnell BA, Lacko AG. A Spontaneous Assembling Lipopeptide Nanoconjugate Transporting the Anthracycline Drug N-Benzyladriamycin-14-valerate for Personalized Therapy of Ewing Sarcoma. Bioconjug Chem 2024; 35:187-202. [PMID: 38318778 DOI: 10.1021/acs.bioconjchem.3c00429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
To meet the current need for a tumor-selective, targeted therapy regimen associated with reduced toxicity, our laboratory has developed a spontaneously assembled nanostructure that resembles high-density lipoproteins (HDLs). These myristoyl-5A (MYR-5A) nanotransporters are designed to safely transport lipophilic pharmaceuticals, including a novel anthracycline drug (N-benzyladriamycin-14-valerate (AD198)). This formulation has been found to enhance the therapeutic efficacy and reduced toxicity of drugs in preclinical studies of 2D and 3D models of Ewing sarcoma (EWS) and cardiomyocytes. Our findings indicate that the MYR-5A/AD198 nanocomplex delivers its payload selectively to cancer cells via the scavenger receptor type B1 (SR-B1), thus providing a solid proof of concept for the development of an improved and highly effective, potentially personalized therapy for EWS while protecting against treatment-associated cardiotoxicity.
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Affiliation(s)
- Nirupama Sabnis
- Lipoprotein Drug Delivery Research Laboratory, Department of Microbiology, Immunology & Genetics, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - Sangram Raut
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - Bhavani Nagarajan
- North Texas Research Eye Institute, Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - Ammar Kapic
- Lipoprotein Drug Delivery Research Laboratory, Department of Microbiology, Immunology & Genetics, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - Akpedje Serena Dossou
- Lipoprotein Drug Delivery Research Laboratory, Department of Microbiology, Immunology & Genetics, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - Leonard Lothstein
- Department of Pathology and Laboratory Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee 38103, United States
| | - Rafal Fudala
- Lipoprotein Drug Delivery Research Laboratory, Department of Microbiology, Immunology & Genetics, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - Bruce A Bunnell
- Lipoprotein Drug Delivery Research Laboratory, Department of Microbiology, Immunology & Genetics, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - Andras G Lacko
- Lipoprotein Drug Delivery Research Laboratory, Department of Microbiology, Immunology & Genetics, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
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3
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Sacher S, Mukherjee A, Ray A. Deciphering structural aspects of reverse cholesterol transport: mapping the knowns and unknowns. Biol Rev Camb Philos Soc 2023; 98:1160-1183. [PMID: 36880422 DOI: 10.1111/brv.12948] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 02/03/2023] [Accepted: 02/24/2023] [Indexed: 03/08/2023]
Abstract
Atherosclerosis is a major contributor to the onset and progression of cardiovascular disease (CVD). Cholesterol-loaded foam cells play a pivotal role in forming atherosclerotic plaques. Induction of cholesterol efflux from these cells may be a promising approach in treating CVD. The reverse cholesterol transport (RCT) pathway delivers cholesteryl ester (CE) packaged in high-density lipoproteins (HDL) from non-hepatic cells to the liver, thereby minimising cholesterol load of peripheral cells. RCT takes place via a well-organised interplay amongst apolipoprotein A1 (ApoA1), lecithin cholesterol acyltransferase (LCAT), ATP binding cassette transporter A1 (ABCA1), scavenger receptor-B1 (SR-B1), and the amount of free cholesterol. Unfortunately, modulation of RCT for treating atherosclerosis has failed in clinical trials owing to our lack of understanding of the relationship between HDL function and RCT. The fate of non-hepatic CEs in HDL is dependent on their access to proteins involved in remodelling and can be regulated at the structural level. An inadequate understanding of this inhibits the design of rational strategies for therapeutic interventions. Herein we extensively review the structure-function relationships that are essential for RCT. We also focus on genetic mutations that disturb the structural stability of proteins involved in RCT, rendering them partially or completely non-functional. Further studies are necessary for understanding the structural aspects of RCT pathway completely, and this review highlights alternative theories and unanswered questions.
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Affiliation(s)
- Sukriti Sacher
- Department of Computational Biology, Indraprastha Institute of Information Technology, Okhla Phase III, New Delhi, 110019, India
| | - Abhishek Mukherjee
- Dhiti Life Sciences Pvt Ltd, B-107, Okhla Phase I, New Delhi, 110020, India
| | - Arjun Ray
- Department of Computational Biology, Indraprastha Institute of Information Technology, Okhla Phase III, New Delhi, 110019, India
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4
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Jain V, Harper SL, Versace AM, Fingerman D, Brown GS, Bhardwaj M, Crissey MAS, Goldman AR, Ruthel G, Liu Q, Zivkovic A, Stark H, Herlyn M, Gimotty PA, Speicher DW, Amaravadi RK. Targeting UGCG Overcomes Resistance to Lysosomal Autophagy Inhibition. Cancer Discov 2023; 13:454-473. [PMID: 36331284 PMCID: PMC9905280 DOI: 10.1158/2159-8290.cd-22-0535] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 08/10/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022]
Abstract
Lysosomal autophagy inhibition (LAI) with hydroxychloroquine or DC661 can enhance cancer therapy, but tumor regrowth is common. To elucidate LAI resistance, proteomics and immunoblotting demonstrated that LAI induced lipid metabolism enzymes in multiple cancer cell lines. Lipidomics showed that LAI increased cholesterol, sphingolipids, and glycosphingolipids. These changes were associated with striking levels of GM1+ membrane microdomains (GMM) in plasma membranes and lysosomes. Inhibition of cholesterol/sphingolipid metabolism proteins enhanced LAI cytotoxicity. Targeting UDP-glucose ceramide glucosyltransferase (UGCG) synergistically augmented LAI cytotoxicity. Although UGCG inhibition decreased LAI-induced GMM and augmented cell death, UGCG overexpression led to LAI resistance. Melanoma patients with high UGCG expression had significantly shorter disease-specific survival. The FDA-approved UGCG inhibitor eliglustat combined with LAI significantly inhibited tumor growth and improved survival in syngeneic tumors and a therapy-resistant patient-derived xenograft. These findings nominate UGCG as a new cancer target, and clinical trials testing UGCG inhibition in combination with LAI are warranted. SIGNIFICANCE We discovered UGCG-dependent lipid remodeling drives resistance to LAI. Targeting UGCG with a drug approved for a lysosomal storage disorder enhanced LAI antitumor activity without toxicity. LAI and UGCG inhibition could be tested clinically in multiple cancers. This article is highlighted in the In This Issue feature, p. 247.
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Affiliation(s)
- Vaibhav Jain
- Abramson Cancer Center and Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Amanda M. Versace
- Abramson Cancer Center and Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | - Monika Bhardwaj
- Abramson Cancer Center and Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mary Ann S. Crissey
- Abramson Cancer Center and Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Gordon Ruthel
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Qin Liu
- The Wistar Institute, Philadelphia, PA 19104, USA
| | - Aleksandra Zivkovic
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitaetsstr. 1, 40225, Düsseldorf, Germany
| | - Holgar Stark
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitaetsstr. 1, 40225, Düsseldorf, Germany
| | | | - Phyllis A. Gimotty
- Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David W. Speicher
- The Wistar Institute, Philadelphia, PA 19104, USA
- Corresponding authors: Ravi K. Amaravadi, MD, University of Pennsylvania, 852 BRB 2/3, 421 Curie Blvd, Philadelphia, PA 19104, Tel: 215-796-5159, ; David W. Speicher, The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, Tel: 215-898-3972,
| | - Ravi K. Amaravadi
- Abramson Cancer Center and Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Corresponding authors: Ravi K. Amaravadi, MD, University of Pennsylvania, 852 BRB 2/3, 421 Curie Blvd, Philadelphia, PA 19104, Tel: 215-796-5159, ; David W. Speicher, The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, Tel: 215-898-3972,
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5
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Lin C, Mostafa A, Jans A, Wolters JC, Mohamed MR, Van der Vorst EPC, Trautwein C, Bartneck M. Targeting Ligand Independent Tropism of siRNA-LNP by Small Molecules for Directed Therapy of Liver or Myeloid Immune Cells. Adv Healthc Mater 2023:e2202670. [PMID: 36617516 DOI: 10.1002/adhm.202202670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 12/15/2022] [Indexed: 01/10/2023]
Abstract
Hepatic clearance of lipid nanoparticles (LNP) with encapsulated nucleic acids restricts their therapeutic applicability. Therefore, tools for regulating hepatic clearance are of high interest for nucleic acid delivery. To this end, this work employs wild-type (WT) and low-density lipoprotein receptor (Ldlr)-/- mice pretreated with either a leukotriene B4 receptor inhibitor (BLT1i) or a high-density lipoprotein receptor inhibitor (HDLRi) prior to the injection of siRNA-LNP. This work is able to demonstrate significantly increased hepatic uptake of siRNA-LNP by the BLT1i in Ldlr-/- mice by in vivo imaging and discover an induction of specific uptake-related proteins. Irrespective of the inhibitors and Ldlr deficiency, the siRNA-LNP induced RNA-binding and transport-related proteins in liver, including haptoglobin (HP) that is also identified as most upregulated serum protein. This work observes a downregulation of proteins functioning in hepatic detoxification and of serum opsonins. Most strikingly, the HDLRi reduces hepatic uptake and increases siRNA accumulation in spleen and myeloid immune cells of blood and liver. RNA sequencing demonstrates leukocyte recruitment by the siRNA-LNP and the HDLRi through induction of chemokine ligands in liver tissue. The data provide insights into key mechanisms of siRNA-LNP biodistribution and indicate that the HDLRi has potential for extrahepatic and leukocyte targeting.
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Affiliation(s)
- Cheng Lin
- Department of Internal Medicine III, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
- Department of Rheumatology and Shanghai Institute of Rheumatology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Asmaa Mostafa
- Department of Internal Medicine III, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
- Department of Microbial Biotechnology, Biotechnology Research Institute, National Research Center, 33 El-Bohouth St., El-Dokki, Giza, 12622, Egypt
| | - Alexander Jans
- Department of Internal Medicine III, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Justina Clarinda Wolters
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen, 9713 AV, The Netherlands
| | - Mohamed Ramadan Mohamed
- Department of Internal Medicine III, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Emiel P C Van der Vorst
- Interdisciplinary Center for Clinical Research (IZKF), RWTH Aachen University, 52074, Aachen, Germany
- Institute for Molecular Cardiovascular Research (IMCAR), RWTH Aachen University, 52074, Aachen, Germany
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-University Munich, 80336, Munich, Germany
| | - Christian Trautwein
- Department of Internal Medicine III, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Matthias Bartneck
- Department of Internal Medicine III, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
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6
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Tello Rubio B, Bugault F, Baudon B, Raynal B, Brûlé S, Morel JD, Saint-Auret S, Blanchard N, Demangel C, Guenin-Macé L. Molecular Mechanisms Underpinning the Circulation and Cellular Uptake of Mycobacterium ulcerans Toxin Mycolactone. Front Pharmacol 2021; 12:733496. [PMID: 34603049 PMCID: PMC8481864 DOI: 10.3389/fphar.2021.733496] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/06/2021] [Indexed: 11/13/2022] Open
Abstract
Mycolactone is a diffusible lipid toxin produced by Mycobacterium ulcerans, the causative agent of Buruli ulcer disease. Altough bacterially derived mycolactone has been shown to traffic from cutaneous foci of infection to the bloodstream, the mechanisms underpinning its access to systemic circulation and import by host cells remain largely unknown. Using biophysical and cell-based approaches, we demonstrate that mycolactone specific association to serum albumin and lipoproteins is necessary for its solubilization and is a major mechanism to regulate its bioavailability. We also demonstrate that Scavenger Receptor (SR)-B1 contributes to the cellular uptake of mycolactone. Overall, we suggest a new mechanism of transport and cell entry, challenging the dogma that the toxin enters host cells via passive diffusion.
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Affiliation(s)
- Bruno Tello Rubio
- Immunobiology of Infection Unit, INSERM U1221, Institut Pasteur, Paris, France
| | - Florence Bugault
- Immunobiology of Infection Unit, INSERM U1221, Institut Pasteur, Paris, France
| | - Blandine Baudon
- Immunobiology of Infection Unit, INSERM U1221, Institut Pasteur, Paris, France
| | - Bertrand Raynal
- Plateforme de Biophysique Moléculaire, UMR 3528 CNRS, Institut Pasteur, Paris, France
| | - Sébastien Brûlé
- Plateforme de Biophysique Moléculaire, UMR 3528 CNRS, Institut Pasteur, Paris, France
| | - Jean-David Morel
- Immunobiology of Infection Unit, INSERM U1221, Institut Pasteur, Paris, France
| | - Sarah Saint-Auret
- CNRS, LIMA, UMR 7042, Université de Haute-Alsace, Université de Strasbourg, Mulhouse, France
| | - Nicolas Blanchard
- CNRS, LIMA, UMR 7042, Université de Haute-Alsace, Université de Strasbourg, Mulhouse, France
| | - Caroline Demangel
- Immunobiology of Infection Unit, INSERM U1221, Institut Pasteur, Paris, France
| | - Laure Guenin-Macé
- Immunobiology of Infection Unit, INSERM U1221, Institut Pasteur, Paris, France
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7
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Pandey M, Cuddihy G, Gordon JA, Cox ME, Wasan KM. Inhibition of Scavenger Receptor Class B Type 1 (SR-B1) Expression and Activity as a Potential Novel Target to Disrupt Cholesterol Availability in Castration-Resistant Prostate Cancer. Pharmaceutics 2021; 13:1509. [PMID: 34575583 PMCID: PMC8467449 DOI: 10.3390/pharmaceutics13091509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/04/2021] [Accepted: 09/08/2021] [Indexed: 02/07/2023] Open
Abstract
There have been several studies that have linked elevated scavenger receptor class b type 1 (SR-B1) expression and activity to the development and progression of castration-resistant prostate cancer (CRPC). SR-B1 facilitates the influx of cholesterol to the cell from lipoproteins in systemic circulation. This influx of cholesterol may be important for many cellular functions, including the synthesis of androgens. Castration-resistant prostate cancer tumors can synthesize androgens de novo to supplement the loss of exogenous sources often induced by androgen deprivation therapy. Silencing of SR-B1 may impact the ability of prostate cancer cells, particularly those of the castration-resistant state, to maintain the intracellular supply of androgens by removing a supply of cholesterol. SR-B1 expression is elevated in CRPC models and has been linked to poor survival of patients. The overarching belief has been that cholesterol modulation, through either synthesis or uptake inhibition, will impact essential signaling processes, impeding the proliferation of prostate cancer. The reduction in cellular cholesterol availability can impede prostate cancer proliferation through both decreased steroid synthesis and steroid-independent mechanisms, providing a potential therapeutic target for the treatment of prostate cancer. In this article, we discuss and highlight the work on SR-B1 as a potential novel drug target for CRPC management.
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Affiliation(s)
- Mitali Pandey
- Department of Urological Sciences, Faculty of Medicine, University of British Columbia, Vancouver Prostate Centre, Vancouver, BC V6T 1Z3, Canada; (M.P.); (M.E.C.)
| | - Grace Cuddihy
- College of Pharmacy and Nutrition, University of Saskatchewan, 104 Clinic Place, Saskatoon, SK S7N 2Z4, Canada;
| | - Jacob A. Gordon
- Oncology Bioscience, Oncology R&D, AstraZeneca, Boston, MA 02451, USA;
| | - Michael E. Cox
- Department of Urological Sciences, Faculty of Medicine, University of British Columbia, Vancouver Prostate Centre, Vancouver, BC V6T 1Z3, Canada; (M.P.); (M.E.C.)
| | - Kishor M. Wasan
- Department of Urological Sciences, Faculty of Medicine, University of British Columbia, Vancouver Prostate Centre, Vancouver, BC V6T 1Z3, Canada; (M.P.); (M.E.C.)
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8
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Fujita K, Koide N, Somiya M, Kuroda S, Hinuma S. A regulatory role of scavenger receptor class B type 1 in endocytosis and lipid droplet formation induced by liposomes containing phosphatidylethanolamine in HEK293T cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1868:118859. [PMID: 32956759 DOI: 10.1016/j.bbamcr.2020.118859] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 09/03/2020] [Accepted: 09/16/2020] [Indexed: 12/16/2022]
Abstract
We have recently reported that phosphatidylethanolamine (PE)-containing liposomes are endocytosed and then induce lipid droplets (LDs) in HEK293T cells. In this study, we elucidated a mechanism responsible for endocytosis of PE-containing liposomes and induction of LDs. By using fluorescence-labeled liposomes and flow cytometry, we found that PE-containing liposomes were very efficiently internalized in HEK293T cells. However, Block lipid transporter-1 (BLT-1) only marginally suppressed the uptake of these liposomes, indicating that entire liposomes were mostly taken up in these cells. They were therefore inferred to express abundant PE receptors responsible for endocytosis of PE-containing liposomes. We examined the expression of 52 candidate genes through transcriptomic analyses and eventually narrowed it down to four candidate genes, which were abundantly expressed in HEK293T cells. Among siRNAs targeting these candidates, scavenger receptor class B type 1 (SR-B1) siRNA showed the most profound reduction in PE liposomal uptake. Conversely, the expression of SR-B1 by transfection of an expression plasmid enhanced the uptake of PE-containing liposomes. After the internalization of PE-containing liposomes, they were colocalized with endosomes/lysosomes and SR-B1, which indicates that these liposomes are taken up in HEK293T cells at least partially through the endosomal/lysosomal pathway. A specific anti-SR-B1-antibody blocked the uptake of PE-containing liposomes in HEK293T cells while LD formation in these cells induced by PE-containing liposomes was suppressed by treatment with SR-B1 siRNA. These results demonstrate that SR-B1 functions as a receptor for the endocytosis of PE-containing liposomes and regulates the formation of LDs induced by PE-containing liposomes in HEK293T cells.
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Affiliation(s)
- Kazuyo Fujita
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan; Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Faculty of Human Life Science, Senri Kinran University, Suita, Osaka 565-0873, Japan.
| | - Narumi Koide
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan; Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan.
| | - Masaharu Somiya
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan.
| | - Shun'ichi Kuroda
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan; Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan.
| | - Shuji Hinuma
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan.
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9
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Cholesterol uptake and efflux are impaired in human trophoblast cells from pregnancies with maternal supraphysiological hypercholesterolemia. Sci Rep 2020; 10:5264. [PMID: 32210256 PMCID: PMC7093446 DOI: 10.1038/s41598-020-61629-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 02/17/2020] [Indexed: 12/14/2022] Open
Abstract
Maternal physiological (MPH) or supraphysiological hypercholesterolaemia (MSPH) occurs during pregnancy. Cholesterol trafficking from maternal to foetal circulation requires the uptake of maternal LDL and HDL by syncytiotrophoblast and cholesterol efflux from this multinucleated tissue to ApoA-I and HDL. We aimed to determine the effects of MSPH on placental cholesterol trafficking. Placental tissue and primary human trophoblast (PHT) were isolated from pregnant women with total cholesterol <280 md/dL (MPH, n = 27) or ≥280 md/dL (MSPH, n = 28). The lipid profile in umbilical cord blood from MPH and MSPH neonates was similar. The abundance of LDL receptor (LDLR) and HDL receptor (SR-BI) was comparable between MSPH and MPH placentas. However, LDLR was localized mainly in the syncytiotrophoblast surface and was associated with reduced placental levels of its ligand ApoB. In PHT from MSPH, the uptake of LDL and HDL was lower compared to MPH, without changes in LDLR and reduced levels of SR-BI. Regarding cholesterol efflux, in MSPH placentas, the abundance of cholesterol transporter ABCA1 was increased, while ABCG1 and SR-BI were reduced. In PHT from MSPH, the cholesterol efflux to ApoA-I was increased and to HDL was reduced, along with reduced levels of ABCG1, compared to MPH. Inhibition of SR-BI did not change cholesterol efflux in PHT. The TC content in PHT was comparable in MPH and MSPH cells. However, free cholesterol was increased in MSPH cells. We conclude that MSPH alters the trafficking and content of cholesterol in placental trophoblasts, which could be associated with changes in the placenta-mediated maternal-to-foetal cholesterol trafficking.
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10
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Wang W, Yan Z, Hu J, Shen WJ, Azhar S, Kraemer FB. Scavenger receptor class B, type 1 facilitates cellular fatty acid uptake. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158554. [PMID: 31678516 DOI: 10.1016/j.bbalip.2019.158554] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 09/21/2019] [Accepted: 09/25/2019] [Indexed: 02/07/2023]
Abstract
SR-B1 belongs to the class B scavenger receptor, or CD36 super family. SR-B1 and CD36 share an affinity for a wide array of ligands. Although they exhibit similar ligand binding specificity, SR-B1 and CD36 have some very specific lipid transport functions. Whereas SR-B1 primarily facilitates the selective delivery of cholesteryl esters (CEs) and cholesterol from HDL particles to the liver and non-placental steroidogenic tissues, as well as participating in cholesterol efflux from cells, CD36 primarily mediates the uptake of long-chain fatty acids in high fatty acid-requiring organs such as the heart, skeletal muscle and adipose tissue. However, CD36 also mediates cholesterol efflux and facilitates selective lipoprotein-CE delivery, although less efficiently than SR-B1. Interestingly, the ability or efficiency of SR-B1 to mediate fatty acid uptake has not been reported. In this paper, using overexpression and siRNA-mediated knockdown of SR-B1, we show that SR-B1 possesses the ability to facilitate fatty acid uptake. Moreover, this function is not blocked by BLT-1, a specific chemical inhibitor of HDL-CE uptake activity of SR-B1, nor by sulfo-N-succinimidyl oleate, which inhibits fatty acid uptake by CD36. Attenuated fatty acid uptake was also observed in primary adipocytes isolated from SR-B1 knockout mice. In conclusion, facilitation of fatty acid uptake is an additional function that is mediated by SR-B1.
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Affiliation(s)
- Wei Wang
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States of America; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States of America; Department of Endocrinology, Peking University First Hospital, Beijing, China
| | - Zhe Yan
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States of America; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States of America; Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu, China
| | - Jie Hu
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States of America; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States of America
| | - Wen-Jun Shen
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States of America; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States of America.
| | - Salman Azhar
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States of America; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States of America
| | - Fredric B Kraemer
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States of America; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States of America.
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11
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Gordon JA, Noble JW, Midha A, Derakhshan F, Wang G, Adomat HH, Tomlinson Guns ES, Lin YY, Ren S, Collins CC, Nelson PS, Morrissey C, Wasan KM, Cox ME. Upregulation of Scavenger Receptor B1 Is Required for Steroidogenic and Nonsteroidogenic Cholesterol Metabolism in Prostate Cancer. Cancer Res 2019; 79:3320-3331. [PMID: 31064850 PMCID: PMC6606386 DOI: 10.1158/0008-5472.can-18-2529] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 02/25/2019] [Accepted: 04/30/2019] [Indexed: 12/19/2022]
Abstract
Aberrant cholesterol metabolism is increasingly appreciated to be essential for prostate cancer initiation and progression. Transcript expression of the high-density lipoprotein-cholesterol receptor scavenger receptor B1 (SR-B1) is elevated in primary prostate cancer. Hypothesizing that SR-B1 expression may help facilitate malignant transformation, we document increased SR-B1 protein and transcript expression in prostate cancer relative to normal prostate epithelium that persists in lethal castration-resistant prostate cancer (CRPC) metastasis. As intratumoral steroid synthesis from the precursor cholesterol can drive androgen receptor (AR) pathway activity in CRPC, we screened androgenic benign and cancer cell lines for sensitivity to SR-B1 antagonism. Benign cells were insensitive to SR-B1 antagonism, and cancer line sensitivity inversely correlated with expression levels of full-length and splice variant AR. In androgen-responsive CRPC cell model C4-2, SR-B1 antagonism suppressed cholesterol uptake, de novo steroidogenesis, and AR activity. SR-B1 antagonism also suppressed growth and viability and induced endoplasmic reticulum stress and autophagy. The inability of exogenous steroids to reverse these effects indicates that AR pathway activation is insufficient to overcome cytotoxic stress caused by a decrease in the availability of cholesterol. Furthermore, SR-B1 antagonism decreased cholesterol uptake, growth, and viability of the AR-null CRPC cell model PC-3, and the small-molecule SR-B1 antagonist block lipid transport-1 decreased xenograft growth rate despite poor pharmacologic properties. Overall, our findings show that SR-B1 is upregulated in primary and castration-resistant disease and is essential for cholesterol uptake needed to drive both steroidogenic and nonsteroidogenic biogenic pathways, thus implicating SR-B1 as a novel and potentially actionable target in CRPC. SIGNIFICANCE: These findings highlight SR-B1 as a potential target in primary and castration-resistant prostate cancer that is essential for cholesterol uptake needed to drive steroidogenic and nonsteroidogenic biogenic pathways.
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MESH Headings
- Androgens/metabolism
- Animals
- Apoptosis
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Bone Neoplasms/metabolism
- Bone Neoplasms/secondary
- Bone Neoplasms/surgery
- Cell Proliferation
- Cholesterol/metabolism
- Gene Expression Regulation, Neoplastic
- Humans
- Liver Neoplasms/metabolism
- Liver Neoplasms/secondary
- Liver Neoplasms/surgery
- Lung Neoplasms/metabolism
- Lung Neoplasms/secondary
- Lung Neoplasms/surgery
- Male
- Mice
- Mice, Nude
- Orchiectomy
- Prognosis
- Prostatic Neoplasms, Castration-Resistant/metabolism
- Prostatic Neoplasms, Castration-Resistant/pathology
- Prostatic Neoplasms, Castration-Resistant/surgery
- Receptors, Androgen/genetics
- Receptors, Androgen/metabolism
- Scavenger Receptors, Class B/genetics
- Scavenger Receptors, Class B/metabolism
- Tumor Cells, Cultured
- Xenograft Model Antitumor Assays
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Affiliation(s)
- Jacob A Gordon
- Vancouver Prostate Centre, Vancouver Coastal Health Research Institute, Vancouver, Canada
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - Jake W Noble
- Vancouver Prostate Centre, Vancouver Coastal Health Research Institute, Vancouver, Canada
| | - Ankur Midha
- Institute of Immunology, Freie Universität Berlin, Berlin, Germany
| | - Fatemeh Derakhshan
- Department of Pathology, British Columbia Cancer Agency, Vancouver, Canada
| | - Gang Wang
- Department of Pathology, British Columbia Cancer Agency, Vancouver, Canada
| | - Hans H Adomat
- Vancouver Prostate Centre, Vancouver Coastal Health Research Institute, Vancouver, Canada
| | - Emma S Tomlinson Guns
- Vancouver Prostate Centre, Vancouver Coastal Health Research Institute, Vancouver, Canada
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - Yen-Yi Lin
- Vancouver Prostate Centre, Vancouver Coastal Health Research Institute, Vancouver, Canada
| | - Shancheng Ren
- Department of Urology, Second Military Medical University, Shanghai, China
| | - Collin C Collins
- Vancouver Prostate Centre, Vancouver Coastal Health Research Institute, Vancouver, Canada
| | - Peter S Nelson
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Colm Morrissey
- Department of Urology, University of Washington, Seattle, Washington
| | - Kishor M Wasan
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Canada
| | - Michael E Cox
- Vancouver Prostate Centre, Vancouver Coastal Health Research Institute, Vancouver, Canada.
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
- Department of Urologic Sciences, University of British Columbia, Canada
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12
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Fuentes M, Santander N, Cortés V. Insulin increases cholesterol uptake, lipid droplet content, and apolipoprotein B secretion in CaCo-2 cells by upregulating SR-BI via a PI3K, AKT, and mTOR-dependent pathway. J Cell Biochem 2019; 120:1550-1559. [PMID: 30278109 DOI: 10.1002/jcb.27410] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 07/10/2018] [Indexed: 01/24/2023]
Abstract
The actions of insulin on intestinal cholesterol absorption and lipoprotein secretion are not well understood. Herein, we determined the effects of insulin on the levels of cholesterol transporter scavenger receptor, class B, type I (SR-BI), cellular cholesterol uptake, intracellular lipid accumulation, and lipoprotein secretion in a cellular model of human intestinal epithelium. METHODS CaCo-2 cells were cultured to postconfluency in Transwell filters and stimulated with glucose (25 mM) in the presence or absence of insulin (100 nM) at their basolateral surface. SR-BI mRNA and protein levels were quantified by quantitative reverse transcription-PCR and immunoblot, respectively. Polarized localization of SR-BI was determined by cell surface proteins biotinylation and streptavidin precipitation. Activities of PI3K, AKT, mTOR, and SR-BI were pharmacologically antagonized. Cholesterol uptake was assessed by NBD-cholesterol incorporation. Apolipoprotein (apo) B concentration was quantified by ELISA. Subcellular localization of neutral lipids (BODIPY) and SR-BI (immunofluorescence) was determined by confocal microscopy. RESULTS In polarized CaCo-2 cells, insulin increased SR-BI at the mRNA and protein levels. SR-BI was exclusively present at apical cell surface, as indicated by biotinylation and confocal microscopy analysis. Glucose did not modify SR-BI abundance or subcellular localization. Effects of insulin on SR-BI levels were abrogated by PI3K, AKT, or mTOR pharmacological antagonism. Cholesterol uptake, neutral lipid abundance, and apo B secretion were increased by insulin in CaCo-2 cells, and these effects were prevented by SR-BI pharmacological antagonism with block lipid transport-1. CONCLUSIONS insulin promotes cholesterol uptake, intracellular lipid store, and apo B-containing lipoproteins secretion by SR-BI-dependent mechanisms in a model of human intestinal epithelium.
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Affiliation(s)
- Marcela Fuentes
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nicolás Santander
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Víctor Cortés
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
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13
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Conrad KS, Cheng TW, Ysselstein D, Heybrock S, Hoth LR, Chrunyk BA, Am Ende CW, Krainc D, Schwake M, Saftig P, Liu S, Qiu X, Ehlers MD. Lysosomal integral membrane protein-2 as a phospholipid receptor revealed by biophysical and cellular studies. Nat Commun 2017; 8:1908. [PMID: 29199275 PMCID: PMC5712522 DOI: 10.1038/s41467-017-02044-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 11/03/2017] [Indexed: 12/17/2022] Open
Abstract
Lysosomal integral membrane protein-2 (LIMP-2/SCARB2) contributes to endosomal and lysosomal function. LIMP-2 deficiency is associated with neurological abnormalities and kidney failure and, as an acid glucocerebrosidase receptor, impacts Gaucher and Parkinson's diseases. Here we report a crystal structure of a LIMP-2 luminal domain dimer with bound cholesterol and phosphatidylcholine. Binding of these lipids alters LIMP-2 from functioning as a glucocerebrosidase-binding monomer toward a dimeric state that preferentially binds anionic phosphatidylserine over neutral phosphatidylcholine. In cellular uptake experiments, LIMP-2 facilitates transport of phospholipids into murine fibroblasts, with a strong substrate preference for phosphatidylserine. Taken together, these biophysical and cellular studies define the structural basis and functional importance of a form of LIMP-2 for lipid trafficking. We propose a model whereby switching between monomeric and dimeric forms allows LIMP-2 to engage distinct binding partners, a mechanism that may be shared by SR-BI and CD36, scavenger receptor proteins highly homologous to LIMP-2.
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Affiliation(s)
- Karen S Conrad
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA
| | - Ting-Wen Cheng
- Neuroscience Research Unit, Pfizer Worldwide R&D, 610 Main Street, Cambridge, MA, 02139, USA
| | - Daniel Ysselstein
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Saskia Heybrock
- Biochemical Institute, Christian-Albrechts University Kiel, Olshausenstrasse 40, D-24098, Kiel, Germany
| | - Lise R Hoth
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA
| | - Boris A Chrunyk
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA
| | - Christopher W Am Ende
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA
| | - Dimitri Krainc
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Michael Schwake
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Paul Saftig
- Biochemical Institute, Christian-Albrechts University Kiel, Olshausenstrasse 40, D-24098, Kiel, Germany
| | - Shenping Liu
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA.
| | - Xiayang Qiu
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA.
| | - Michael D Ehlers
- Neuroscience Research Unit, Pfizer Worldwide R&D, 610 Main Street, Cambridge, MA, 02139, USA
- Biogen, 225 Binney St., Cambridge, MA, 02142, USA
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14
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Zimetti F, De Vuono S, Gomaraschi M, Adorni MP, Favari E, Ronda N, Ricci MA, Veglia F, Calabresi L, Lupattelli G. Plasma cholesterol homeostasis, HDL remodeling and function during the acute phase reaction. J Lipid Res 2017; 58:2051-2060. [PMID: 28830907 DOI: 10.1194/jlr.p076463] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 08/19/2017] [Indexed: 12/18/2022] Open
Abstract
Acute phase reaction (APR) is a systemic inflammation triggered by several conditions associated with lipid profile alterations. We evaluated whether APR also associates with changes in cholesterol synthesis and absorption, HDL structure, composition, and cholesterol efflux capacity (CEC). We analyzed 59 subjects with APR related to infections, oncologic causes, or autoimmune diseases and 39 controls. We detected no difference in markers of cholesterol synthesis and absorption. Conversely, a significant reduction of LpA-I- and LpAI:AII-containing HDL (-28% and -44.8%, respectively) and of medium-sized HDL (-10.5%) occurred in APR. Total HDL CEC was impaired in APR subjects (-18%). Evaluating specific CEC pathways, we found significant reductions in CEC by aqueous diffusion and by the transporters scavenger receptor B-I and ABCG1 (-25.5, -41.1 and -30.4%, respectively). ABCA1-mediated CEC was not affected. Analyses adjusted for age and gender provided similar results. In addition, correcting for HDL-cholesterol (HDL-C) levels, the differences in aqueous diffusion total and ABCG1-CEC remained significant. APR subjects displayed higher levels of HDL serum amyloid A (+20-folds; P = 0.003). In conclusion, APR does not associate with cholesterol synthesis and absorption changes but with alterations of HDL composition and a marked impairment of HDL CEC, partly independent of HDL-C serum level reduction.
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Affiliation(s)
| | - Stefano De Vuono
- Department of Medicine, Internal Medicine, "Santa Maria della Misericordia" Hospital, University of Perugia, Perugia, Italy
| | - Monica Gomaraschi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Centro E. Grossi Paoletti, Università degli Studi di Milano, Milano, Italy
| | | | - Elda Favari
- Department of Food and Drug, University of Parma, Parma, Italy
| | - Nicoletta Ronda
- Department of Food and Drug, University of Parma, Parma, Italy
| | - Maria Anastasia Ricci
- Department of Medicine, Internal Medicine, "Santa Maria della Misericordia" Hospital, University of Perugia, Perugia, Italy
| | | | - Laura Calabresi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Centro E. Grossi Paoletti, Università degli Studi di Milano, Milano, Italy
| | - Graziana Lupattelli
- Department of Medicine, Internal Medicine, "Santa Maria della Misericordia" Hospital, University of Perugia, Perugia, Italy
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15
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Abstract
PURPOSE OF REVIEW Scavenger receptor BI (SR-BI) is classically known for its role in antiatherogenic reverse cholesterol transport as it selectively takes up cholesterol esters from HDL. Here, we have highlighted recent literature that describes novel functions for SR-BI in physiology and disease. RECENT FINDINGS A large population-based study has revealed that patients heterozygous for the P376L mutant form of SR-BI showed significantly increased levels of plasma HDL-cholesterol and had increased risk of cardiovascular disease, demonstrating that SR-BI in humans is a significant determinant of cardiovascular disease. Furthermore, SR-BI has been shown to modulate the susceptibility to LPS-induced tissue injury and the ability of sphingosine 1 phosphate to interact with its receptor, linking SR-BI to the regulation of inflammation. In addition, important domains within the molecule (Trp-415) as well as novel regulators (procollagen C-endopeptidase enhancer protein 2) of SR-BI's selective uptake function have recently been identified. Moreover, relatively high expression levels of the SR-BI protein have been observed in a variety of cancer tissues, which is associated with a reduced overall survival rate. SUMMARY The HDL receptor SR-BI is a potential therapeutic target not only in the cardiovascular disease setting, but also in inflammatory conditions as well as in cancer.
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Affiliation(s)
- Menno Hoekstra
- Division of Biopharmaceutics, Cluster BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden, The Netherlands, , Tel: +31-71-5276582
| | - Mary Sorci-Thomas
- Division of Endocrinology, Associate in Pharmacology and Toxicology, Medical College of Wisconsin, Senior Adjunct Investigator at the Blood Research Institute, Blood Center of Wisconsin, , Tel: 414-955-5728
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16
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Yahya R, Favari E, Calabresi L, Verhoeven A, Zimetti F, Adorni M, Gomaraschi M, Averna M, Cefalù A, Bernini F, Sijbrands E, Mulder M, Roeters van Lennep J. Lomitapide affects HDL composition and function. Atherosclerosis 2016; 251:15-18. [DOI: 10.1016/j.atherosclerosis.2016.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/03/2016] [Accepted: 05/04/2016] [Indexed: 12/23/2022]
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17
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Leahy T, Gadella BM. New insights into the regulation of cholesterol efflux from the sperm membrane. Asian J Androl 2016; 17:561-7. [PMID: 25926609 PMCID: PMC4492045 DOI: 10.4103/1008-682x.153309] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Cholesterol is an essential component of the mammalian plasma membrane because it promotes membrane stability without comprising membrane fluidity. Given this important cellular role, cholesterol levels are tightly controlled at multiple levels. It has been clearly shown that cholesterol redistribution and depletion from the sperm membrane is a key part of the spermatozoon's preparation for fertilization. Some factors that regulate these events are described (e.g., bicarbonate, calcium) but the mechanisms underlying cholesterol export are poorly understood. How does a hydrophobic cholesterol molecule inserted in the sperm plasma membrane enter the energetically unfavorable aqueous surroundings? This review will provide an overview of knowledge in this area and highlight our gaps in understanding. The overall aim is to better understand cholesterol redistribution in the sperm plasma membrane, its relation to the possible activation of a cholesterol transporter and the role of cholesterol acceptors. Armed with such knowledge, sperm handling techniques can be adapted to better prepare spermatozoa for in vitro and in vivo fertilization.
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Affiliation(s)
| | - Bart M Gadella
- Department of Farm Animal Health and of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 2, 3584 CM Utrecht, The Netherlands
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18
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Sparks SM, Zhou H, Generaux C, Harston L, Moncol D, Jayawickreme C, Parham J, Condreay P, Rimele T. Identification of nonabsorbable inhibitors of the scavenger receptor-BI (SR-BI) for tissue-specific administration. Bioorg Med Chem Lett 2016; 26:1901-4. [PMID: 26988301 DOI: 10.1016/j.bmcl.2016.03.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/07/2016] [Accepted: 03/08/2016] [Indexed: 01/01/2023]
Abstract
The identification of a low-permeability scavenger receptor BI (SR-BI) inhibitor starting from the ITX-5061 template is described. Structure-activity and structure-permeability relationships were assessed for analogs leading to the identification of compound 8 as a potent and nonabsorbable SR-BI inhibitor.
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Affiliation(s)
- Steven M Sparks
- GlaxoSmithKline, Enteroendocrine Discovery Performance Unit and Platform Technology and Science, 5 Moore Drive, Research Triangle Park, NC 27709, United States.
| | - Huiqiang Zhou
- GlaxoSmithKline, Enteroendocrine Discovery Performance Unit and Platform Technology and Science, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - Claudia Generaux
- GlaxoSmithKline, Enteroendocrine Discovery Performance Unit and Platform Technology and Science, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - Lindsey Harston
- GlaxoSmithKline, Enteroendocrine Discovery Performance Unit and Platform Technology and Science, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - David Moncol
- GlaxoSmithKline, Enteroendocrine Discovery Performance Unit and Platform Technology and Science, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - Channa Jayawickreme
- GlaxoSmithKline, Enteroendocrine Discovery Performance Unit and Platform Technology and Science, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - Janet Parham
- GlaxoSmithKline, Enteroendocrine Discovery Performance Unit and Platform Technology and Science, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - Patrick Condreay
- GlaxoSmithKline, Enteroendocrine Discovery Performance Unit and Platform Technology and Science, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - Thomas Rimele
- GlaxoSmithKline, Enteroendocrine Discovery Performance Unit and Platform Technology and Science, 5 Moore Drive, Research Triangle Park, NC 27709, United States
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19
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Srimanee A, Regberg J, Hällbrink M, Vajragupta O, Langel Ü. Role of scavenger receptors in peptide-based delivery of plasmid DNA across a blood-brain barrier model. Int J Pharm 2016; 500:128-35. [PMID: 26773601 DOI: 10.1016/j.ijpharm.2016.01.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 12/31/2015] [Accepted: 01/05/2016] [Indexed: 01/01/2023]
Abstract
Receptor-mediated transcytosis remains a major route for drug delivery across the blood-brain barrier (BBB). PepFect 32 (PF32), a peptide-based vector modified with targeting ligand (Angiopep-2) binding to low-density lipoprotein receptor-related protein-1 (LRP-1), was previously found to be a promising vector for plasmid delivery across an in vitro model of the BBB. Cellular uptake of PF32/plasmid DNA (pDNA) complexes was speculated the internalization via LRP-1 receptor. In this study, we prove that PF32/pDNA nanocomplexes are not only transported into brain endothelial cells via LRP-1 receptor-mediated endocytosis, but also via scavenger receptor class A and B (SCARA3, SCARA5, and SR-BI)-mediated endocytosis. SCARA3, SCARA5, and SR-BI are found to be expressed in the brain endothelial cells. Inhibition of these receptors leads to a reduction of the transfection. In conclusion, this study shows that scavenger receptors also play an essential role in the cellular uptake of the PF32/pDNA nanocomplexes.
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Affiliation(s)
- Artita Srimanee
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayudhya Rd., 10400 Bangkok, Thailand; Department of Neurochemistry, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.
| | - Jakob Regberg
- Department of Neurochemistry, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Mattias Hällbrink
- Department of Neurochemistry, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Opa Vajragupta
- Excellent Center for Innovation in Drug Design and Discovery, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayudhya Rd., 10400 Bangkok, Thailand
| | - Ülo Langel
- Department of Neurochemistry, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden; Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
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20
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Lino M, Farr S, Baker C, Fuller M, Trigatti B, Adeli K. Intestinal scavenger receptor class B type I as a novel regulator of chylomicron production in healthy and diet-induced obese states. Am J Physiol Gastrointest Liver Physiol 2015; 309:G350-9. [PMID: 26138463 DOI: 10.1152/ajpgi.00086.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 06/25/2015] [Indexed: 01/31/2023]
Abstract
The small intestine contributes to diabetic dyslipidemia through the overproduction of apolipoprotein B48 (apoB48)-containing chylomicron particles. An important regulator of chylomicron generation is dietary lipid absorption, underlining the potential involvement of intestinal lipid transporters for developing dyslipidemia. Intestinal expression of scavenger receptor class B type I (SR-BI) has been found to be upregulated in animal models of insulin resistance. Here we characterized the potential importance of SR-BI in contributing to chylomicron production and postprandial hypertriglyceridemia in vivo. Postprandial triglyceride (TG)-rich lipoprotein (TRL) production was characterized in hamsters treated with the SR-BI inhibitor to block lipid transport-1 (BLT-1) under healthy conditions or conditions of diet-induced obesity and dyslipidemia. BLT-1 (1 mg/kg) or vehicle was administered acutely in chow-fed hamsters or gavaged twice daily over 10 days during high-fructose, high-fat, high-cholesterol (FFC) feeding. Effects of acute SR-BI inhibition by BLT-1 were confirmed in healthy fat-loaded rats. Finally, plasma lipid levels were compared between SR-BI(-/-) mice and their wild-type counterparts fed either chow or a 12-wk high-fat diet. Acute BLT-1 treatment reduced postprandial plasma and TRL TG levels in healthy hamsters and rats. Chronic BLT-1 treatment of FFC-fed hamsters blunted diet-induced weight gain and fasting hypertriglyceridemia, and lowered postprandial TRL-TG, -cholesterol, and -apoB48 levels. Finally, SR-BI(-/-) mice displayed lower plasma and TRL TG levels relative to wild type, and diet-induced weight gain and postprandial hypertriglyceridemia were hindered in SR-BI(-/-) mice. We conclude that intestinal SR-BI is a critical regulator of postprandial lipoprotein production, emphasizing its potential as a target for preventing diabetic dyslipidemia.
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Affiliation(s)
- Marsel Lino
- Department of Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; and
| | - Sarah Farr
- Department of Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; and
| | - Chris Baker
- Department of Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mark Fuller
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Bernardo Trigatti
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Khosrow Adeli
- Department of Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; and
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21
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Neculai D, Schwake M, Ravichandran M, Zunke F, Collins RF, Peters J, Neculai M, Plumb J, Loppnau P, Pizarro JC, Seitova A, Trimble WS, Saftig P, Grinstein S, Dhe-Paganon S. Structure of LIMP-2 provides functional insights with implications for SR-BI and CD36. Nature 2013; 504:172-6. [PMID: 24162852 DOI: 10.1038/nature12684] [Citation(s) in RCA: 207] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Accepted: 09/20/2013] [Indexed: 11/09/2022]
Abstract
Members of the CD36 superfamily of scavenger receptor proteins are important regulators of lipid metabolism and innate immunity. They recognize normal and modified lipoproteins, as well as pathogen-associated molecular patterns. The family consists of three members: SR-BI (which delivers cholesterol to the liver and steroidogenic organs and is a co-receptor for hepatitis C virus), LIMP-2/LGP85 (which mediates lysosomal delivery of β-glucocerebrosidase and serves as a receptor for enterovirus 71 and coxsackieviruses) and CD36 (a fatty-acid transporter and receptor for phagocytosis of effete cells and Plasmodium-infected erythrocytes). Notably, CD36 is also a receptor for modified lipoproteins and β-amyloid, and has been implicated in the pathogenesis of atherosclerosis and of Alzheimer's disease. Despite their prominent roles in health and disease, understanding the function and abnormalities of the CD36 family members has been hampered by the paucity of information about their structure. Here we determine the crystal structure of LIMP-2 and infer, by homology modelling, the structure of SR-BI and CD36. LIMP-2 shows a helical bundle where β-glucocerebrosidase binds, and where ligands are most likely to bind to SR-BI and CD36. Remarkably, the crystal structure also shows the existence of a large cavity that traverses the entire length of the molecule. Mutagenesis of SR-BI indicates that the cavity serves as a tunnel through which cholesterol(esters) are delivered from the bound lipoprotein to the outer leaflet of the plasma membrane. We provide evidence supporting a model whereby lipidic constituents of the ligands attached to the receptor surface are handed off to the membrane through the tunnel, accounting for the selective lipid transfer characteristic of SR-BI and CD36.
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Affiliation(s)
- Dante Neculai
- Cell Biology Program, The Hospital for Sick Children, Toronto M5G 1X8, Canada
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22
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Aharoni S, Aviram M, Fuhrman B. Paraoxonase 1 (PON1) reduces macrophage inflammatory responses. Atherosclerosis 2013; 228:353-61. [PMID: 23582715 DOI: 10.1016/j.atherosclerosis.2013.03.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 02/17/2013] [Accepted: 03/06/2013] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Paraoxonase 1 (PON1) was suggested to play an anti-inflammatory role. In the present study we questioned whether PON1 has a direct impact on macrophage inflammatory responses, and the possible functional implications of such effects. METHODS AND RESULTS Ex-vivo studies were performed with bone marrow-derived macrophages (BMDM) harvested from C57BL/6 and human-PON1 transgenic (PON1-Tg) mice, and for the in vitro studies the J774.A1 macrophage-like cell line was used. Pro-inflammatory (M1) activation was induced by LPS and INFγ. The spontaneous and M1-induced TNFα and IL-6 secretion were significantly reduced in BMDM derived from PON1-Tg vs. C57BL/6 mice. In vitro, PON1 dose-dependently attenuated both the spontaneous and M1-induced TNFα and IL-6 secretion, and contributed to the anti-inflammatory activity of HDL. Functionally, PON1 attenuated M1-induced production of reactive oxygen species (ROS), phagocytosis, and necrotic macrophage death. PON1 anti-inflammatory activity was mediated, at least in part, via binding to SR-BI, but was independent of the enzyme catalytic activity or of cholesterol efflux stimulation, and did not involve binding to ABCA1. CONCLUSIONS The present study demonstrates, for the first time, that PON1 directly suppresses macrophage pro-inflammatory responses. These findings suggest that PON1 decreases sustained pro-inflammatory reactions, which subsequently can attenuate plaque progression.
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Affiliation(s)
- Saar Aharoni
- The Lipid Research Laboratory, Technion Faculty of Medicine, The Rappaport Family Institute for Research in the Medical Sciences, and Rambam Medical Center, Haifa 31096, Israel
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23
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Yu M, Lau TY, Carr SA, Krieger M. Contributions of a disulfide bond and a reduced cysteine side chain to the intrinsic activity of the high-density lipoprotein receptor SR-BI. Biochemistry 2012. [PMID: 23205738 DOI: 10.1021/bi301203x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The high-density lipoprotein (HDL) receptor scavenger receptor class B, type I (SR-BI), binds HDL and mediates selective cholesteryl ester uptake. SR-BI's structure and mechanism are poorly understood. We used mass spectrometry to assign the two disulfide bonds in SR-BI that connect cysteines within the conserved Cys(321)-Pro(322)-Cys(323) (CPC) motif and connect Cys(280) to Cys(334). We used site-specific mutagenesis to evaluate the contributions of the CPC motif and the side chain of extracellular Cys(384) to HDL binding and lipid uptake. The effects of CPC mutations on activity were context-dependent. Full wild-type (WT) activity required Pro(322) and Cys(323) only when Cys(321) was present. Reduced intrinsic activities were observed for CXC and CPX, but not XXC, XPX, or XXX mutants (X ≠ WT residue). Apparently, a free thiol side chain at position 321 that cannot form an intra-CPC disulfide bond with Cys(323) is deleterious, perhaps because of aberrant disulfide bond formation. Pro(322) may stabilize an otherwise strained CPC disulfide bond, thus supporting WT activity, but this disulfide bond is not absolutely required for normal activity. C(384)X (X = S, T, L, Y, G, or A) mutants exhibited altered activities that varied with the side chain's size: larger side chains phenocopied WT SR-BI treated with its thiosemicarbazone inhibitor BLT-1 (enhanced binding, weakened uptake); smaller side chains produced almost inverse effects (increased uptake:binding ratio). C(384)X mutants were BLT-1-resistant, supporting the proposal that Cys(384)'s thiol interacts with BLT-1. We discuss the implications of our findings on the functions of the extracellular loop cysteines in SR-BI and compare our results to those presented by other laboratories.
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Affiliation(s)
- Miao Yu
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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24
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Lai WA, Yeh YT, Lee MT, Wu LS, Ke FC, Hwang JJ. Ovarian granulosa cells utilize scavenger receptor SR-BI to evade cellular cholesterol homeostatic control for steroid synthesis. J Lipid Res 2012. [PMID: 23197320 DOI: 10.1194/jlr.m030239] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cellular cholesterol is known to be under homeostatic control in nonsteroidogenic cells, and this intrigued us to understand how such control works in steroidogenic cells that additionally use cholesterol for steroid hormone synthesis. We employed primary culture of rat ovarian granulosa cells to study how steroidogenic cells adapt to acquire sufficient cholesterol to meet the demand of active steroidogenesis under the stimulation of gonadotropin follicle-stimulating hormone (FSH) and cytokine transforming growth factor (TGF)β1. We found that TGFβ1 potentiated FSH to upregulate scavenger receptor class B member I (SR-BI) and LDL receptor (LDLR), both functional in uptaking cholesterol as hHDL(3) and hLDL supplementation enhanced progesterone production, and the effect of each lipoprotein was completely or partially blocked by SR-BI selective inhibitor BLT-1. Uptaken cholesterol could also be stored in lipid droplets. Importantly, LDLR and SR-BI responded to sterol with different sensitivity. Giving cells lipoproteins or 25-hydroxycholesterol downregulated Ldlr but not Scarb1; Scarb1 was ultimately downregulated by excessive sterol accumulation under 25-hydroxycholesterol and aminoglutethimide (inhibitor of steroidogenesis) cotreatment. Furthermore, transcription factors sterol regulatory element-binding protein (SREBP)-2 and liver receptor homolog (LRH)-1 crucially mediated Ldlr and Scarb1 differential response to sterol challenge. This study reveals that ovarian granulosa cells retain the cholesterol homeostatic control machinery like nonsteroidogenic cells, although during active steroidogenesis, they utilize SR-BI to evade such feedback control.
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Affiliation(s)
- Wei-An Lai
- Institute of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
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25
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Saddar S, Carriere V, Lee WR, Tanigaki K, Yuhanna IS, Parathath S, Morel E, Warrier M, Sawyer JK, Gerard RD, Temel RE, Brown JM, Connelly M, Mineo C, Shaul PW. Scavenger receptor class B type I is a plasma membrane cholesterol sensor. Circ Res 2012; 112:140-51. [PMID: 23023567 DOI: 10.1161/circresaha.112.280081] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Signal initiation by the high-density lipoprotein (HDL) receptor scavenger receptor class B, type I (SR-BI), which is important to actions of HDL on endothelium and other processes, requires cholesterol efflux and the C-terminal transmembrane domain. The C-terminal transmembrane domain uniquely interacts with plasma membrane (PM) cholesterol. OBJECTIVE The molecular basis and functional significance of SR-BI interaction with PM cholesterol are unknown. We tested the hypotheses that the interaction is required for SR-BI signaling, and that it enables SR-BI to serve as a PM cholesterol sensor. METHODS AND RESULTS In studies performed in COS-M6 cells, mutation of a highly conserved C-terminal transmembrane domain glutamine to alanine (SR-BI-Q445A) decreased PM cholesterol interaction with the receptor by 71% without altering HDL binding or cholesterol uptake or efflux, and it yielded a receptor incapable of HDL-induced signaling. Signaling prompted by cholesterol efflux to methyl-β-cyclodextrin also was prevented, indicating that PM cholesterol interaction with the receptor enables it to serve as a PM cholesterol sensor. Using SR-BI-Q445A, we further demonstrated that PM cholesterol sensing by SR-BI does not influence SR-BI-mediated reverse cholesterol transport to the liver in mice. However, the PM cholesterol sensing does underlie apolipoprotein B intracellular trafficking in response to postprandial micelles or methyl-β-cyclodextrin in cultured enterocytes, and it is required for HDL activation of endothelial NO synthase and migration in cultured endothelial cells and HDL-induced angiogenesis in vivo. CONCLUSIONS Through interaction with PM cholesterol, SR-BI serves as a PM cholesterol sensor, and the resulting intracellular signaling governs processes in both enterocytes and endothelial cells.
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Affiliation(s)
- Sonika Saddar
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
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26
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Respective contributions of intestinal Niemann-Pick C1-like 1 and scavenger receptor class B type I to cholesterol and tocopherol uptake: in vivo v. in vitro studies. Br J Nutr 2011; 107:1296-304. [PMID: 21929836 DOI: 10.1017/s0007114511004405] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The intestinal absorption of cholesterol and lipid micronutrients such as vitamin E has been shown to share some common pathways. The present study aims to further compare the uptake of cholesterol ([3H]cholesterol v. 22-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-23,24-bisnor-5-cholen-3-ol (NBD-cholesterol)) and tocopherol in Caco-2 TC-7 cells and in mouse intestine, with special focus on the respective roles of scavenger receptor class B type I (SR-BI) and Niemann-Pick C1-like 1 (NPC1L1). Conversely to NBD-cholesterol, the uptakes of [3H]cholesterol and tocopherol by Caco-2 cells were impaired by both block lipid transport-1 and ezetimibe, which inhibit SR-BI and NPC1L1, respectively. These inhibitions occurred only when cholesterol or tocopherol was delivered to cells included in micelles that contained biliary acid and at least oleic acid as a lipid. In vivo, after 2 h of digestion in mice, the uptake of the two cholesterol analogues and of tocopherol all showed distinct patterns along the duodenum-jejunum axis. [3H]Cholesterol uptake, which correlated closely to NPC1L1 mRNA expression in wild-type (wt) mice, was strongly inhibited by ezetimibe. Intestinal SR-BI overexpression did not change NPC1L1 expression and led to a significant increase in [3H]cholesterol uptake in the distal jejunum. Conversely, neither ezetimibe treatment nor SR-BI overexpression had an effect on NBD-cholesterol uptake. However, in contrast with SR-BI mRNA expression, tocopherol absorption increased strongly up to the distal jejunum in wt mice where it was specifically inhibited by ezetimibe, and was increased in the proximal intestine of intestinal SR-BI-overexpressing mice. Thus, cholesterol and tocopherol uptakes share common pathways in cell culture models, but display different in vivo absorption patterns associated with distinct contributions of SR-BI and NPC1L1.
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27
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Efficient in vivo delivery of siRNA into brain capillary endothelial cells along with endogenous lipoprotein. Mol Ther 2011; 19:2213-21. [PMID: 21915100 DOI: 10.1038/mt.2011.186] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The brain capillary endothelial cell (BCEC) is a major functional component of the blood-brain barrier and is an underlying factor in the pathophysiology of various diseases, including brain ischemia, multiple sclerosis, and neurodegenerative disorders. We examined gene silencing in BCECs by using endogenous lipoprotein to introduce short-interfering RNA (siRNA) in vivo. A cholesterol-conjugated 21/23-mer siRNA targeting organic anion transporter 3 (OAT3) mRNA (Chol-siOAT3) was intravenously injected into mice after its incorporation into extracted endogenous lipoproteins. Chol-siOAT3 was not delivered to neurons or glia, but was successfully delivered into BCECs and resulted in a significant reduction of OAT3 mRNA levels when injected after its incorporation into high-density lipoprotein (HDL). Efficient delivery was not achieved, however, when Chol-siOAT3 was injected without any lipoproteins, or after its incorporation into low-density lipoprotein (LDL). Investigations in apolipoprotein E (ApoE)-deficient and LDL receptor (LDLR)-deficient mice revealed that the uptake of HDL-containing Chol-siOAT3 was mainly mediated by ApoE and LDLR in mice. These findings indicate that siRNA can be delivered into BCECs in vivo by using endogenous lipoprotein, which could make this strategy useful as a new gene silencing therapy for diseases involving BCECs.
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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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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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30
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Paatela H, Vihma V, Jauhiainen M, Mervaala E, Tikkanen MJ. Dehydroepiandrosterone fatty acyl esters in high density lipoprotein: interaction with human vascular endothelial cells and vascular responses ex vivo. Steroids 2011; 76:376-80. [PMID: 21168430 DOI: 10.1016/j.steroids.2010.12.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 12/09/2010] [Accepted: 12/11/2010] [Indexed: 01/14/2023]
Abstract
Dehydroepiandrosterone (DHEA) fatty acyl esters once incorporated in high density lipoprotein (HDL) induce a stronger vasodilatory response in rat mesenteric arteries ex vivo compared to native HDL. We studied the role of HDL receptor, scavenger receptor class B, type 1 (SR-B1), as well as estrogen and androgen receptors in the vasodilatory response of HDL-associated DHEA fatty acyl esters. Using cultured human vascular endothelial cells (HUVEC), we investigated the possible internalization and cellular response of HDL-associated DHEA esters. We prepared DHEA ester-enriched HDL by incubating human plasma in the presence of DHEA. After isolation and purification, HDL was added in cumulative doses to arterial rings precontracted with noradrenaline. Inhibition of the function of SR-B1 almost completely abolished maximal vasorelaxation by DHEA-enriched HDL while estrogen or androgen receptor blockage had no significant effect. When HUVECs were incubated in the presence of [³H]DHEA ester-enriched HDL, the amount of intracellular [³H]-radioactivity increased steadily during 24 h. Blocking of SR-B1 reduced this uptake by a mean of 30%. The proportion of unesterified [³H]DHEA, as analyzed by thin-layer chromatography, increased intracellularly and in the cell culture media after several hours of incubation of the cells in the presence of [³H]DHEA ester-enriched HDL. This indicated slow hydrolysis of DHEA fatty acyl esters and subsequent excretion of unesterified DHEA by the cells. In conclusion, DHEA-enriched HDL induced vasorelaxation via the SR-B1-facilitated pathway. However, this vasodilation is not likely to be attributed to rapid hydrolysis of HDL-associated DHEA esters by the vascular endothelium.
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Affiliation(s)
- Hanna Paatela
- Department of Medicine, Helsinki University Central Hospital and Folkhälsan Research Center, 00290 Helsinki, Finland
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31
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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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32
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James RW, Brulhart-Meynet MC, Singh AK, Riederer B, Seidler U, Out R, Van Berkel TJ, Deakin S. The Scavenger Receptor Class B, Type I Is a Primary Determinant of Paraoxonase-1 Association With High-Density Lipoproteins. Arterioscler Thromb Vasc Biol 2010; 30:2121-7. [DOI: 10.1161/atvbaha.110.209122] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Objective—
To examine the contribution of the scavenger receptor (SR) BI to the mechanism by which high-density lipoprotein (HDL) acquires paraoxonase-1 (PON1).
Methods and Results—
Serum PON1 activity contributes to the antioxidant capacity of HDLs and is suggested to be an independent risk factor for atherosclerosis. The association of PON1 with HDL is a major determinant of its serum activity levels. PON1 secretion was studied in stably transfected Chinese hamster ovary and HepG2 models. Complementary analyses were performed in transgenic models. Modulation of SR-BI expression, by SR-BI small and interfering RNA knockdown and pharmacologically, correlated with significant changes (
P
<0.01) in PON1 secretion to HDLs and very-low-density lipoproteins. Block lipid transport-1 (BLT1), which increases the affinity of HDL for SR-BI without modulating its expression, was associated with significant increases in secretion. Downregulating postsynaptic density 95/disc-large/zona occludens kinase in HepG2 reduced cell SR-BI protein and lowered enzyme secretion. Serum PON1 activity was significantly reduced in postsynaptic density 95/disc-large/zona occludens kinase knockout mice.
Conclusion—
The present study identifies SR-BI as a major determinant of the capacity of HDL to acquire PON1. It reinforces the concept of the receptor as a docking molecule, allowing communication between HDL and the cell, and extends the importance of SR-BI to HDL metabolism and function.
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Affiliation(s)
- Richard W. James
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
| | - Marie-Claude Brulhart-Meynet
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
| | - Anurag Kumar Singh
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
| | - Brigitte Riederer
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
| | - Ursula Seidler
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
| | - Ruud Out
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
| | - Theo J.C. Van Berkel
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
| | - Sara Deakin
- From the Clinical Diabetes Unit, the Department of Internal Medicine (R.W.J., M.-C.B.-M., and S.D.), Medical Faculty, Geneva, Switzerland; the Department of Gastroenterology (A.K.S., B.R., and U.S.), Hannover Medical School, Hannover, Germany; and Gorlaeus Laboratories (R.O. and T.J.C.V.B.), University of Leiden, Leiden, the Netherlands
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Rich RL, Myszka DG. Grading the commercial optical biosensor literature-Class of 2008: 'The Mighty Binders'. J Mol Recognit 2010; 23:1-64. [PMID: 20017116 DOI: 10.1002/jmr.1004] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Optical biosensor technology continues to be the method of choice for label-free, real-time interaction analysis. But when it comes to improving the quality of the biosensor literature, education should be fundamental. Of the 1413 articles published in 2008, less than 30% would pass the requirements for high-school chemistry. To teach by example, we spotlight 10 papers that illustrate how to implement the technology properly. Then we grade every paper published in 2008 on a scale from A to F and outline what features make a biosensor article fabulous, middling or abysmal. To help improve the quality of published data, we focus on a few experimental, analysis and presentation mistakes that are alarmingly common. With the literature as a guide, we want to ensure that no user is left behind.
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Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
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Masson D, Koseki M, Ishibashi M, Larson CJ, Miller SG, King BD, Tall AR. Increased HDL cholesterol and apoA-I in humans and mice treated with a novel SR-BI inhibitor. Arterioscler Thromb Vasc Biol 2009; 29:2054-60. [PMID: 19815817 DOI: 10.1161/atvbaha.109.191320] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Increasing HDL levels is a potential strategy for the treatment of atherosclerosis. METHODS AND RESULTS ITX5061, a molecule initially characterized as a p38 MAPK inhibitor, increased HDL-C levels by 20% in a human population of hypertriglyceridemic subjects with low HDL levels. ITX5061 also moderately increased apoA-I but did not affect VLDL/LDL cholesterol or plasma triglyceride concentrations. ITX5061 increased HDL-C in WT and human apoA-I transgenic mice, and kinetic experiments showed that ITX5061 decreased the fractional catabolic rate of HDL-CE and reduced its hepatic uptake. In transfected cells, ITX5061 inhibited SR-BI-dependent uptake of HDL-CE. Moreover, ITX5061 failed to increase HDL-C levels in SR-BI(-/-) mice. To assess effects on atherosclerosis, ITX5061 was given to atherogenic diet-fed Ldlr(+/-) mice with or without CETP expression for 18 weeks. In both the control and CETP-expressing groups, ITX5061-treated mice displayed reductions of early atherosclerotic lesions in the aortic arch -40%, P<0.05), and a nonsignificant trend to reduced lesion area in the proximal aorta. CONCLUSIONS Our data indicate that ITX5061 increases HDL-C levels by inhibition of SR-BI activity. This suggests that pharmacological inhibition of SR-BI has the potential to raise HDL-C and apoA-I levels without adverse effects on VLDL/LDL cholesterol levels in humans.
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Affiliation(s)
- David Masson
- Division of Molecular Medicine, Department of Medicine, Columbia University, New York, USA.
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Stefulj J, Panzenboeck U, Becker T, Hirschmugl B, Schweinzer C, Lang I, Marsche G, Sadjak A, Lang U, Desoye G, Wadsack C. Human Endothelial Cells of the Placental Barrier Efficiently Deliver Cholesterol to the Fetal Circulation via ABCA1 and ABCG1. Circ Res 2009; 104:600-8. [DOI: 10.1161/circresaha.108.185066] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Although maternal–fetal cholesterol transfer may serve to compensate for insufficient fetal cholesterol biosynthesis under pathological conditions, it may have detrimental consequences under conditions of maternal hypercholesterolemia leading to preatherosclerotic lesion development in fetal aortas. Maternal cholesterol may enter fetal circulation by traversing syncytiotrophoblast and endothelial layers of the placenta. We hypothesized that endothelial cells (ECs) of the fetoplacental vasculature display a high and tightly regulated capacity for cholesterol release. Using ECs isolated from human term placenta (HPECs), we investigated cholesterol release capacity and examined transporters involved in cholesterol efflux pathways controlled by liver-X-receptors (LXRs). HPECs demonstrated 2.5-fold higher cholesterol release to lipid-free apolipoprotein (apo)A-I than human umbilical vein ECs (HUVECs), whereas both cell types showed similar cholesterol efflux to high-density lipoproteins (HDLs). Interestingly, treatment of HPECs with LXR activators increased cholesterol efflux to both types of acceptors, whereas no such response could be observed for HUVECs. In line with enhanced cholesterol efflux, LXR activation in HPECs increased expression of ATP-binding cassette transporters ABCA1 and ABCG1, while not altering expression of ABCG4 and scavenger receptor class B type I (SR-BI). Inhibition of ABCA1 or silencing of ABCG1 decreased cholesterol efflux to apoA-I (−70%) and HDL
3
(−57%), respectively. Immunohistochemistry localized both transporters predominantly to the apical membranes of placental ECs in situ. Thus, ECs of human term placenta exhibit unique, efficient and LXR-regulated cholesterol efflux mechanisms. We propose a sequential pathway mediated by ABCA1 and ABCG1, respectively, by which HPECs participate in forming mature HDL in the fetal blood.
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Affiliation(s)
- Jasminka Stefulj
- From the Institute of Pathophysiology and Immunology (J.S., U.P., T.B., C.S., A.S.); Clinic of Obstetrics and Gynecology (B.H., U.L., G.D., C.W.); Institute of Cell Biology, Histology and Embryology (I.L.); and Institute of Experimental and Clinical Pharmacology (G.M.), Medical University Graz, Austria; and Department of Molecular Biology (J.S.), Rudjer Boskovic Institute, Zagreb, Croatia
| | - Ute Panzenboeck
- From the Institute of Pathophysiology and Immunology (J.S., U.P., T.B., C.S., A.S.); Clinic of Obstetrics and Gynecology (B.H., U.L., G.D., C.W.); Institute of Cell Biology, Histology and Embryology (I.L.); and Institute of Experimental and Clinical Pharmacology (G.M.), Medical University Graz, Austria; and Department of Molecular Biology (J.S.), Rudjer Boskovic Institute, Zagreb, Croatia
| | - Tatjana Becker
- From the Institute of Pathophysiology and Immunology (J.S., U.P., T.B., C.S., A.S.); Clinic of Obstetrics and Gynecology (B.H., U.L., G.D., C.W.); Institute of Cell Biology, Histology and Embryology (I.L.); and Institute of Experimental and Clinical Pharmacology (G.M.), Medical University Graz, Austria; and Department of Molecular Biology (J.S.), Rudjer Boskovic Institute, Zagreb, Croatia
| | - Birgit Hirschmugl
- From the Institute of Pathophysiology and Immunology (J.S., U.P., T.B., C.S., A.S.); Clinic of Obstetrics and Gynecology (B.H., U.L., G.D., C.W.); Institute of Cell Biology, Histology and Embryology (I.L.); and Institute of Experimental and Clinical Pharmacology (G.M.), Medical University Graz, Austria; and Department of Molecular Biology (J.S.), Rudjer Boskovic Institute, Zagreb, Croatia
| | - Cornelia Schweinzer
- From the Institute of Pathophysiology and Immunology (J.S., U.P., T.B., C.S., A.S.); Clinic of Obstetrics and Gynecology (B.H., U.L., G.D., C.W.); Institute of Cell Biology, Histology and Embryology (I.L.); and Institute of Experimental and Clinical Pharmacology (G.M.), Medical University Graz, Austria; and Department of Molecular Biology (J.S.), Rudjer Boskovic Institute, Zagreb, Croatia
| | - Ingrid Lang
- From the Institute of Pathophysiology and Immunology (J.S., U.P., T.B., C.S., A.S.); Clinic of Obstetrics and Gynecology (B.H., U.L., G.D., C.W.); Institute of Cell Biology, Histology and Embryology (I.L.); and Institute of Experimental and Clinical Pharmacology (G.M.), Medical University Graz, Austria; and Department of Molecular Biology (J.S.), Rudjer Boskovic Institute, Zagreb, Croatia
| | - Gunther Marsche
- From the Institute of Pathophysiology and Immunology (J.S., U.P., T.B., C.S., A.S.); Clinic of Obstetrics and Gynecology (B.H., U.L., G.D., C.W.); Institute of Cell Biology, Histology and Embryology (I.L.); and Institute of Experimental and Clinical Pharmacology (G.M.), Medical University Graz, Austria; and Department of Molecular Biology (J.S.), Rudjer Boskovic Institute, Zagreb, Croatia
| | - Anton Sadjak
- From the Institute of Pathophysiology and Immunology (J.S., U.P., T.B., C.S., A.S.); Clinic of Obstetrics and Gynecology (B.H., U.L., G.D., C.W.); Institute of Cell Biology, Histology and Embryology (I.L.); and Institute of Experimental and Clinical Pharmacology (G.M.), Medical University Graz, Austria; and Department of Molecular Biology (J.S.), Rudjer Boskovic Institute, Zagreb, Croatia
| | - Uwe Lang
- From the Institute of Pathophysiology and Immunology (J.S., U.P., T.B., C.S., A.S.); Clinic of Obstetrics and Gynecology (B.H., U.L., G.D., C.W.); Institute of Cell Biology, Histology and Embryology (I.L.); and Institute of Experimental and Clinical Pharmacology (G.M.), Medical University Graz, Austria; and Department of Molecular Biology (J.S.), Rudjer Boskovic Institute, Zagreb, Croatia
| | - Gernot Desoye
- From the Institute of Pathophysiology and Immunology (J.S., U.P., T.B., C.S., A.S.); Clinic of Obstetrics and Gynecology (B.H., U.L., G.D., C.W.); Institute of Cell Biology, Histology and Embryology (I.L.); and Institute of Experimental and Clinical Pharmacology (G.M.), Medical University Graz, Austria; and Department of Molecular Biology (J.S.), Rudjer Boskovic Institute, Zagreb, Croatia
| | - Christian Wadsack
- From the Institute of Pathophysiology and Immunology (J.S., U.P., T.B., C.S., A.S.); Clinic of Obstetrics and Gynecology (B.H., U.L., G.D., C.W.); Institute of Cell Biology, Histology and Embryology (I.L.); and Institute of Experimental and Clinical Pharmacology (G.M.), Medical University Graz, Austria; and Department of Molecular Biology (J.S.), Rudjer Boskovic Institute, Zagreb, Croatia
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Béaslas O, Cueille C, Delers F, Chateau D, Chambaz J, Rousset M, Carrière V. Sensing of dietary lipids by enterocytes: a new role for SR-BI/CLA-1. PLoS One 2009; 4:e4278. [PMID: 19169357 PMCID: PMC2627924 DOI: 10.1371/journal.pone.0004278] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Accepted: 12/17/2008] [Indexed: 11/23/2022] Open
Abstract
Background The intestine is responsible for absorbing dietary lipids and delivering them to the organism as triglyceride-rich lipoproteins (TRL). It is important to determine how this process is regulated in enterocytes, the absorptive cells of the intestine, as prolonged postprandial hypertriglyceridemia is a known risk factor for atherosclerosis. During the postprandial period, dietary lipids, mostly triglycerides (TG) hydrolyzed by pancreatic enzymes, are combined with bile products and reach the apical membrane of enterocytes as postprandial micelles (PPM). Our aim was to determine whether these micelles induce, in enterocytes, specific early cell signaling events that could control the processes leading to TRL secretion. Methodology/Principal Findings The effects of supplying PPM to the apex of Caco-2/TC7 enterocytes were analyzed. Micelles devoid of TG hydrolysis products, like those present in the intestinal lumen in the interprandial period, were used as controls. The apical delivery of PPM specifically induced a number of cellular events that are not induced by interprandial micelles. These early events included the trafficking of apolipoprotein B, a structural component of TRL, from apical towards secretory domains, and the rapid, dose-dependent activation of ERK and p38MAPK. PPM supply induced the scavenger receptor SR-BI/CLA-1 to cluster at the apical brush border membrane and to move from non-raft to raft domains. Competition, inhibition or knockdown of SR-BI/CLA-1 impaired the PPM-dependent apoB trafficking and ERK activation. Conclusions/Significance These results are the first evidence that enterocytes specifically sense postprandial dietary lipid-containing micelles. SR-BI/CLA-1 is involved in this process and could be a target for further study with a view to modifying intestinal TRL secretion early in the control pathway.
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Affiliation(s)
- Olivier Béaslas
- Université Pierre et Marie Curie - Paris 6, UMR S 872, Les Cordeliers, Paris, France
- INSERM, U 872, Paris, France
- Université Paris Descartes, UMR S 872, Paris, France
| | - Carine Cueille
- Université Pierre et Marie Curie - Paris 6, UMR S 872, Les Cordeliers, Paris, France
- INSERM, U 872, Paris, France
- Université Paris Descartes, UMR S 872, Paris, France
| | - François Delers
- Université Pierre et Marie Curie - Paris 6, UMR S 872, Les Cordeliers, Paris, France
- INSERM, U 872, Paris, France
- Université Paris Descartes, UMR S 872, Paris, France
| | - Danielle Chateau
- Université Pierre et Marie Curie - Paris 6, UMR S 872, Les Cordeliers, Paris, France
- INSERM, U 872, Paris, France
- Université Paris Descartes, UMR S 872, Paris, France
| | - Jean Chambaz
- Université Pierre et Marie Curie - Paris 6, UMR S 872, Les Cordeliers, Paris, France
- INSERM, U 872, Paris, France
- Université Paris Descartes, UMR S 872, Paris, France
| | - Monique Rousset
- Université Pierre et Marie Curie - Paris 6, UMR S 872, Les Cordeliers, Paris, France
- INSERM, U 872, Paris, France
- Université Paris Descartes, UMR S 872, Paris, France
| | - Véronique Carrière
- Université Pierre et Marie Curie - Paris 6, UMR S 872, Les Cordeliers, Paris, France
- INSERM, U 872, Paris, France
- Université Paris Descartes, UMR S 872, Paris, France
- * E-mail:
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Rodrigues CD, Hannus M, Prudêncio M, Martin C, Gonçalves LA, Portugal S, Epiphanio S, Akinc A, Hadwiger P, Jahn-Hofmann K, Röhl I, van Gemert GJ, Franetich JF, Luty AJF, Sauerwein R, Mazier D, Koteliansky V, Vornlocher HP, Echeverri CJ, Mota MM. Host scavenger receptor SR-BI plays a dual role in the establishment of malaria parasite liver infection. Cell Host Microbe 2008; 4:271-82. [PMID: 18779053 DOI: 10.1016/j.chom.2008.07.012] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 06/27/2008] [Accepted: 07/18/2008] [Indexed: 12/29/2022]
Abstract
An obligatory step of malaria parasite infection is Plasmodium sporozoite invasion of host hepatocytes, and host lipoprotein clearance pathways have been linked to Plasmodium liver infection. By using RNA interference to screen lipoprotein-related host factors, we show here that the class B, type I scavenger receptor (SR-BI) is the strongest regulator of Plasmodium infection among these factors. Inhibition of SR-BI function reduced P. berghei infection in Huh7 cells, and overexpression of SR-BI led to increased infection. In vivo silencing of liver SR-BI expression in mice and inhibition of SR-BI activity in human primary hepatocytes reduced infection by P. berghei and by P. falciparum, respectively. Heterozygous SR-BI(+/-) mice displayed reduced P. berghei infection rates correlating with liver SR-BI expression levels. Additional analyses revealed that SR-BI plays a dual role in Plasmodium infection, affecting both sporozoite invasion and intracellular parasite development, and may therefore constitute a good target for malaria prophylaxis.
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Affiliation(s)
- Cristina D Rodrigues
- Unidade de Malária, Instituto de Medicina Molecular, Universidade de Lisboa, 1649-028 Lisboa, Portugal
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