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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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2
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Yu H. HDL and Scavenger Receptor Class B Type I (SRBI). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1377:79-93. [DOI: 10.1007/978-981-19-1592-5_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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3
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Su X, Ramírez-Escudero M, Sun F, van den Dikkenberg JB, van Steenbergen MJ, Pieters RJ, Janssen BJC, van Hasselt PM, Hennink WE, van Nostrum CF. Internalization and Transport of PEGylated Lipid-Based Mixed Micelles across Caco-2 Cells Mediated by Scavenger Receptor B1. Pharmaceutics 2021; 13:2022. [PMID: 34959304 PMCID: PMC8703698 DOI: 10.3390/pharmaceutics13122022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/12/2021] [Accepted: 11/17/2021] [Indexed: 11/16/2022] Open
Abstract
The aim of this study was to get insight into the internalization and transport of PEGylat-ed mixed micelles loaded by vitamin K, as mediated by Scavenger Receptor B1 (SR-B1) that is abundantly expressed by intestinal epithelium cells as well as by differentiated Caco-2 cells. Inhibition of SR-B1 reduced endocytosis and transport of vitamin-K-loaded 0%, 30% and 50% PEGylated mixed micelles and decreased colocalization of the micelles with SR-B1. Confocal fluorescence microscopy, fluorescence-activated cell sorting (FACS) analysis, and surface plasmon resonance (SPR) were used to study the interaction between the mixed micelles of different compositions (varying vitamin K loading and PEG content) and SR-B1. Interaction of PEGylated micelles was independent of the vitamin K content, indicating that the PEG shell prevented vitamin K exposure at the surface of the micelles and binding with the receptor and that the PEG took over the micelles' ability to bind to the receptor. Molecular docking calculations corroborated the dual binding of both vita-min K and PEG with the binding domain of SR-B1. In conclusion, the improved colloidal stability of PEGylated mixed micelles did not compromise their cellular uptake and transport due to the affinity of PEG for SR-B1. SR-B1 is able to interact with PEGylated nanoparticles and mediates their subsequent internalization and transport.
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Affiliation(s)
- Xiangjie Su
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands; (X.S.); (F.S.); (J.B.v.d.D.); (M.J.v.S.); (W.E.H.)
| | - Mercedes Ramírez-Escudero
- Structural Biochemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, 3584 CG Utrecht, The Netherlands; (M.R.-E.); (B.J.C.J.)
| | - Feilong Sun
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands; (X.S.); (F.S.); (J.B.v.d.D.); (M.J.v.S.); (W.E.H.)
| | - Joep B. van den Dikkenberg
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands; (X.S.); (F.S.); (J.B.v.d.D.); (M.J.v.S.); (W.E.H.)
| | - Mies J. van Steenbergen
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands; (X.S.); (F.S.); (J.B.v.d.D.); (M.J.v.S.); (W.E.H.)
| | - Roland J. Pieters
- Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands;
| | - Bert J. C. Janssen
- Structural Biochemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, 3584 CG Utrecht, The Netherlands; (M.R.-E.); (B.J.C.J.)
| | - Peter M. van Hasselt
- Department of Pediatrics, Wilhelmina Children’s Hospital, University Medical Center Utrecht, 3584 EA Utrecht, The Netherlands;
| | - Wim E. Hennink
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands; (X.S.); (F.S.); (J.B.v.d.D.); (M.J.v.S.); (W.E.H.)
| | - Cornelus F. van Nostrum
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands; (X.S.); (F.S.); (J.B.v.d.D.); (M.J.v.S.); (W.E.H.)
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Vitry J, Paré G, Murru A, Charest-Morin X, Maaroufi H, McLeish KR, Naccache PH, Fernandes MJ. Regulation of the Expression, Oligomerisation and Signaling of the Inhibitory Receptor CLEC12A by Cysteine Residues in the Stalk Region. Int J Mol Sci 2021; 22:ijms221910207. [PMID: 34638548 PMCID: PMC8508511 DOI: 10.3390/ijms221910207] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/11/2021] [Accepted: 09/15/2021] [Indexed: 01/26/2023] Open
Abstract
CLEC12A is a myeloid inhibitory receptor that negatively regulates inflammation in mouse models of autoimmune and autoinflammatory arthritis. Reduced CLEC12A expression enhances myeloid cell activation and inflammation in CLEC12A knock-out mice with collagen antibody-induced or gout-like arthritis. Similarly to other C-type lectin receptors, CLEC12A harbours a stalk domain between its ligand binding and transmembrane domains. While it is presumed that the cysteines in the stalk domain have multimerisation properties, their role in CLEC12A expression and/or signaling remain unknown. We thus used site-directed mutagenesis to determine whether the stalk domain cysteines play a role in CLEC12A expression, internalisation, oligomerisation, and/or signaling. Mutation of C118 blocks CLEC12A transport through the secretory pathway diminishing its cell-surface expression. In contrast, mutating C130 does not affect CLEC12A cell-surface expression but increases its oligomerisation, inducing ligand-independent phosphorylation of the receptor. Moreover, we provide evidence that CLEC12A dimerisation is regulated in a redox-dependent manner. We also show that antibody-induced CLEC12A cross-linking induces flotillin oligomerisation in insoluble membrane domains in which CLEC12A signals. Taken together, these data indicate that the stalk cysteines in CLEC12A differentially modulate this inhibitory receptor’s expression, oligomerisation and signaling, suggestive of the regulation of CLEC12A in a redox-dependent manner during inflammation.
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Affiliation(s)
- Julien Vitry
- CHU de Québec Research Center, Division of Infectious Diseases and Immunology, Laval University, Québec, QC G1V 4G2, Canada; (J.V.); (G.P.); (A.M.); (P.H.N.)
- Department of Microbiology-Infectious Diseases and Immunology, Faculty of Medicine, Laval University, Québec, QC G1V 4G2, Canada;
| | - Guillaume Paré
- CHU de Québec Research Center, Division of Infectious Diseases and Immunology, Laval University, Québec, QC G1V 4G2, Canada; (J.V.); (G.P.); (A.M.); (P.H.N.)
- Department of Microbiology-Infectious Diseases and Immunology, Faculty of Medicine, Laval University, Québec, QC G1V 4G2, Canada;
| | - Andréa Murru
- CHU de Québec Research Center, Division of Infectious Diseases and Immunology, Laval University, Québec, QC G1V 4G2, Canada; (J.V.); (G.P.); (A.M.); (P.H.N.)
- Department of Microbiology-Infectious Diseases and Immunology, Faculty of Medicine, Laval University, Québec, QC G1V 4G2, Canada;
| | - Xavier Charest-Morin
- Department of Microbiology-Infectious Diseases and Immunology, Faculty of Medicine, Laval University, Québec, QC G1V 4G2, Canada;
| | - Halim Maaroufi
- Institute of Integrative Biology and Systems, Laval University, Québec, QC G1V 0A6, Canada;
| | - Kenneth R. McLeish
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY 40206, USA;
| | - Paul H. Naccache
- CHU de Québec Research Center, Division of Infectious Diseases and Immunology, Laval University, Québec, QC G1V 4G2, Canada; (J.V.); (G.P.); (A.M.); (P.H.N.)
- Department of Microbiology-Infectious Diseases and Immunology, Faculty of Medicine, Laval University, Québec, QC G1V 4G2, Canada;
| | - Maria J. Fernandes
- CHU de Québec Research Center, Division of Infectious Diseases and Immunology, Laval University, Québec, QC G1V 4G2, Canada; (J.V.); (G.P.); (A.M.); (P.H.N.)
- Department of Microbiology-Infectious Diseases and Immunology, Faculty of Medicine, Laval University, Québec, QC G1V 4G2, Canada;
- Correspondence: ; Tel.: +1-418-656-4141 (ext. 46106)
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Widjaja-Adhi MAK, Golczak M. The molecular aspects of absorption and metabolism of carotenoids and retinoids in vertebrates. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158571. [PMID: 31770587 PMCID: PMC7244374 DOI: 10.1016/j.bbalip.2019.158571] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 11/04/2019] [Accepted: 11/07/2019] [Indexed: 02/08/2023]
Abstract
Vitamin A is an essential nutrient necessary for numerous basic physiological functions, including reproduction and development, immune cell differentiation and communication, as well as the perception of light. To evade the dire consequences of vitamin A deficiency, vertebrates have evolved specialized metabolic pathways that enable the absorption, transport, and storage of vitamin A acquired from dietary sources as preformed retinoids or provitamin A carotenoids. This evolutionary advantage requires a complex interplay between numerous specialized retinoid-transport proteins, receptors, and enzymes. Recent advances in molecular and structural biology resulted in a rapid expansion of our understanding of these processes at the molecular level. This progress opened new avenues for the therapeutic manipulation of retinoid homeostasis. In this review, we summarize current research related to the biochemistry of carotenoid and retinoid-processing proteins with special emphasis on the structural aspects of their physiological actions. This article is part of a Special Issue entitled Carotenoids recent advances in cell and molecular biology edited by Johannes von Lintig and Loredana Quadro.
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Affiliation(s)
- Made Airanthi K Widjaja-Adhi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America
| | - Marcin Golczak
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America; Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America.
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Duan Z, Zhu Y, Yang Y, He Z, Liu J, Li P, Wang H, Tang B. Fluorescent Imaging for Cysteine Detection In Vivo with High Selectivity. ChemistryOpen 2019; 8:316-320. [PMID: 30886789 PMCID: PMC6401529 DOI: 10.1002/open.201900045] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 02/13/2019] [Indexed: 01/30/2023] Open
Abstract
As an essential amino acid, cysteine is involved in various biosynthetic and metabolic processes, such as protein synthesis, hormone synthesis, and redox homeostatic maintenance. Inordinate cysteine levels are often associated with serious diseases. Thus, designing and synthesizing a novel fluorescent probe for determining the concentration of cellular cysteine, which could indirectly monitor the prevalence of these diseases, is essential. We developed a florescence probe P-Cy with good sensitivity for cysteine detection in vivo. P-Cy only exhibited good response toward cysteine but did not show response toward other biothiols, such as homocysteine (Hcy) and glutathione (GSH). In this study, we used P-Cy by successfully imaging cellular endogenous and exogenous cysteine levels. Furthermore, P-Cy was also performed in mice to detect cysteine level, indicating that P-Cy is a powerful tool for cysteine detection in situ.
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Affiliation(s)
- Zhuwen Duan
- College of Chemistry, Chemical Engineering and Materials Science, Institute of Biomedical Sciences, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of EducationShandong normal UniversityJinan250014PR China
| | - Youming Zhu
- College of Chemistry, Chemical Engineering and Materials Science, Institute of Biomedical Sciences, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of EducationShandong normal UniversityJinan250014PR China
| | - Yuyun Yang
- College of Chemistry, Chemical Engineering and Materials Science, Institute of Biomedical Sciences, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of EducationShandong normal UniversityJinan250014PR China
| | - Zixu He
- College of Chemistry, Chemical Engineering and Materials Science, Institute of Biomedical Sciences, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of EducationShandong normal UniversityJinan250014PR China
| | - Ju Liu
- College of Chemistry, Chemical Engineering and Materials Science, Institute of Biomedical Sciences, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of EducationShandong normal UniversityJinan250014PR China
- Medical Research Center, Shandong Provincial Qianfoshan HospitalShandong UniversityJinan250014PR China
| | - Ping Li
- College of Chemistry, Chemical Engineering and Materials Science, Institute of Biomedical Sciences, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of EducationShandong normal UniversityJinan250014PR China
| | - Hui Wang
- College of Chemistry, Chemical Engineering and Materials Science, Institute of Biomedical Sciences, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of EducationShandong normal UniversityJinan250014PR China
| | - Bo Tang
- College of Chemistry, Chemical Engineering and Materials Science, Institute of Biomedical Sciences, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of EducationShandong normal UniversityJinan250014PR China
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Shen WJ, Asthana S, Kraemer FB, Azhar S. Scavenger receptor B type 1: expression, molecular regulation, and cholesterol transport function. J Lipid Res 2018; 59:1114-1131. [PMID: 29720388 DOI: 10.1194/jlr.r083121] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/26/2018] [Indexed: 12/16/2022] Open
Abstract
Cholesterol is required for maintenance of plasma membrane fluidity and integrity and for many cellular functions. Cellular cholesterol can be obtained from lipoproteins in a selective pathway of HDL-cholesteryl ester (CE) uptake without parallel apolipoprotein uptake. Scavenger receptor B type 1 (SR-B1) is a cell surface HDL receptor that mediates HDL-CE uptake. It is most abundantly expressed in liver, where it provides cholesterol for bile acid synthesis, and in steroidogenic tissues, where it delivers cholesterol needed for storage or steroidogenesis in rodents. SR-B1 transcription is regulated by trophic hormones in the adrenal gland, ovary, and testis; in the liver and elsewhere, SR-B1 is subject to posttranscriptional and posttranslational regulation. SR-B1 operates in several metabolic processes and contributes to pathogenesis of atherosclerosis, inflammation, hepatitis C virus infection, and other conditions. Here, we summarize characteristics of the selective uptake pathway and involvement of microvillar channels as facilitators of selective HDL-CE uptake. We also present the potential mechanisms of SR-B1-mediated selective cholesterol transport; the transcriptional, posttranscriptional, and posttranslational regulation of SR-B1; and the impact of gene variants on expression and function of human SR-B1. A better understanding of this unique pathway and SR-B1's role may yield improved therapies for a wide variety of conditions.
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Affiliation(s)
- Wen-Jun Shen
- Geriatric Research, Education, and Clinical Research Center (GRECC), Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 and Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Stanford, CA 94305
| | - Shailendra Asthana
- Drug Discovery Research Center (DDRC), Translational Health Science and Technology Institute (THSTI), NCR Biotech Science Cluster, Faridabad 121001, Haryana, India
| | - Fredric B Kraemer
- Geriatric Research, Education, and Clinical Research Center (GRECC), Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 and Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Stanford, CA 94305
| | - Salman Azhar
- Geriatric Research, Education, and Clinical Research Center (GRECC), Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 and Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Stanford, CA 94305
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Shen WJ, Azhar S, Kraemer FB. SR-B1: A Unique Multifunctional Receptor for Cholesterol Influx and Efflux. Annu Rev Physiol 2017; 80:95-116. [PMID: 29125794 DOI: 10.1146/annurev-physiol-021317-121550] [Citation(s) in RCA: 230] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The scavenger receptor, class B type 1 (SR-B1), is a multiligand membrane receptor protein that functions as a physiologically relevant high-density lipoprotein (HDL) receptor whose primary role is to mediate selective uptake or influx of HDL-derived cholesteryl esters into cells and tissues. SR-B1 also facilitates the efflux of cholesterol from peripheral tissues, including macrophages, back to liver. As a regulator of plasma membrane cholesterol content, SR-B1 promotes the uptake of lipid soluble vitamins as well as viral entry into host cells. These collective functions of SR-B1 ultimately affect programmed cell death, female fertility, platelet function, vasculature inflammation, and diet-induced atherosclerosis and myocardial infarction. SR-B1 has also been identified as a potential marker for cancer diagnosis and prognosis. Finally, the SR-B1-linked selective HDL-cholesteryl ester uptake pathway is now being evaluated as a gateway for the delivery of therapeutic and diagnostic agents. In this review, we focus on the regulation and functional significance of SR-B1 in mediating cholesterol movement into and out of cells.
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Affiliation(s)
- Wen-Jun Shen
- Division of Endocrinology, Gerontology and Metabolism, Stanford University School of Medicine, Stanford, California 94305; .,VA Palo Alto Health Care System, Palo Alto, California 94304
| | - Salman Azhar
- Division of Endocrinology, Gerontology and Metabolism, Stanford University School of Medicine, Stanford, California 94305; .,VA Palo Alto Health Care System, Palo Alto, California 94304
| | - Fredric B Kraemer
- Division of Endocrinology, Gerontology and Metabolism, Stanford University School of Medicine, Stanford, California 94305; .,VA Palo Alto Health Care System, Palo Alto, California 94304
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9
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Mooberry LK, Sabnis NA, Panchoo M, Nagarajan B, Lacko AG. Targeting the SR-B1 Receptor as a Gateway for Cancer Therapy and Imaging. Front Pharmacol 2016; 7:466. [PMID: 28018216 PMCID: PMC5156841 DOI: 10.3389/fphar.2016.00466] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 11/16/2016] [Indexed: 01/25/2023] Open
Abstract
Malignant tumors display remarkable heterogeneity to the extent that even at the same tissue site different types of cells with varying genetic background may be found. In contrast, a relatively consistent marker the scavenger receptor type B1 (SR-B1) has been found to be consistently overexpressed by most tumor cells. Scavenger Receptor Class B Type I (SR-BI) is a high density lipoprotein (HDL) receptor that facilitates the uptake of cholesterol esters from circulating lipoproteins. Additional findings suggest a critical role for SR-BI in cholesterol metabolism, signaling, motility, and proliferation of cancer cells and thus a potential major impact in carcinogenesis and metastasis. Recent findings indicate that the level of SR-BI expression correlate with aggressiveness and poor survival in breast and prostate cancer. Moreover, genomic data show that depending on the type of cancer, high or low SR-BI expression may promote poor survival. This review discusses the importance of SR-BI as a diagnostic as well as prognostic indicator of cancer to help elucidate the contributions of this protein to cancer development, progression, and survival. In addition, the SR-B1 receptor has been shown to serve as a potential gateway for the delivery of therapeutic agents when reconstituted high density lipoprotein nanoparticles are used for their transport to cancer cells and tumors. Opportunities for the development of new technologies, particularly in the areas of cancer therapy and tumor imaging are discussed.
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Affiliation(s)
- Linda K. Mooberry
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort WorthTX, USA
| | - Nirupama A. Sabnis
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort WorthTX, USA
| | - Marlyn Panchoo
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort WorthTX, USA
| | - Bhavani Nagarajan
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort WorthTX, USA
| | - Andras G. Lacko
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort WorthTX, USA
- Department of Pediatrics, University of North Texas Health Science Center, Fort WorthTX, USA
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Witting PK. Measuring redox-active species in cells and tissues. Focus on "A case of mistaken identity: are reactive oxygen species actually reactive sulfide species?". Am J Physiol Regul Integr Comp Physiol 2016; 310:R547-8. [PMID: 26887430 DOI: 10.1152/ajpregu.00049.2016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 02/11/2016] [Indexed: 11/22/2022]
Affiliation(s)
- Paul K Witting
- Discipline of Pathology, Sydney Medical School, Charles Perkins Centre, The University of Sydney, New South Wales, Australia
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11
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Gunnoo SB, Madder A. Chemical Protein Modification through Cysteine. Chembiochem 2016; 17:529-53. [DOI: 10.1002/cbic.201500667] [Citation(s) in RCA: 242] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Indexed: 12/15/2022]
Affiliation(s)
- Smita B. Gunnoo
- Organic & Biomimetic Chemistry Research Group; Department of Organic and Macromolecular Chemistry; Ghent University; Krijgslaan 281 9000 Gent Belgium
| | - Annemieke Madder
- Organic & Biomimetic Chemistry Research Group; Department of Organic and Macromolecular Chemistry; Ghent University; Krijgslaan 281 9000 Gent Belgium
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Abstract
The adrenal gland is one of the prominent sites for steroid hormone synthesis. Lipoprotein-derived cholesterol esters (CEs) delivered via SR-B1 constitute the dominant source of cholesterol for steroidogenesis, particularly in rodents. Adrenocorticotropic hormone (ACTH) stimulates steroidogenesis through downstream actions on multiple components involved in steroidogenesis. Both acute and chronic ACTH treatments can modulate SR-B1 function, including its transcription, posttranscriptional stability, phosphorylation and dimerization status, as well as the interaction with other protein partners, all of which result in changes in the ability of SR-B1 to mediate HDL-CE uptake and the supply of cholesterol for conversion to steroids. Here, we provide a review of the recent findings on the regulation of adrenal SR-B1 function by ACTH.
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Affiliation(s)
- Wen-Jun Shen
- The Division of Endocrinology, Stanford University, Stanford, CA, USA
- Geriatric Research, Education and Clinical Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Salman Azhar
- The Division of Endocrinology, Stanford University, Stanford, CA, USA
- Geriatric Research, Education and Clinical Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Fredric B. Kraemer
- The Division of Endocrinology, Stanford University, Stanford, CA, USA
- Geriatric Research, Education and Clinical Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
- *Correspondence: Fredric B. Kraemer,
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Hu Z, Hu J, Shen WJ, Kraemer FB, Azhar S. A Novel Role of Salt-Inducible Kinase 1 (SIK1) in the Post-Translational Regulation of Scavenger Receptor Class B Type 1 Activity. Biochemistry 2015; 54:6917-30. [PMID: 26567857 DOI: 10.1021/acs.biochem.5b00147] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Salt-inducible kinase 1 (SIK1) is a serine/threonine kinase that belongs to the stress- and energy-sensing AMPK family of kinases. SIK1 expression is rapidly induced in Y1 adrenal cells in response to ACTH via the cAMP-PKA signaling cascade, and it has been suggested that an increased level of SIK1 expression inhibits adrenal steroidogenesis by repressing the cAMP-dependent transcription of steroidogenic proteins, CYP11A1 and StAR, by attenuating CREB transcriptional activity. Here we show that SIK1 stimulates adrenal steroidogenesis by modulating the selective HDL-CE transport activity of SR-B1. Overexpression of SIK1 increases cAMP-stimulated and SR-B1-mediated selective HDL-BODIPY-CE uptake in cell lines without impacting SR-B1 protein levels, whereas knockdown of SIK1 attenuated cAMP-stimulated selective HDL-BODIPY-CE uptake. SIK1 forms a complex with SR-B1 by interacting with its cytoplasmic C-terminal domain, and in vitro kinase activity measurements indicate that SIK1 can phosphorylate the C-terminal domain of SR-B1. Among potential phosphorylation sites, SIK1-catalyzed phosphorylation of Ser496 is critical for SIK1 stimulation of the selective CE transport activity of SR-B1. Mutational studies further demonstrated that both the intact catalytic activity of SIK1 and its PKA-catalyzed phosphorylation are essential for SIK1 stimulation of SR-B1 activity. Finally, overexpression of SIK1 caused time-dependent increases in SR-B1-mediated and HDL-supported steroid production in Y1 cells; however, these effects were lost with knockdown of SR-B1. Taken together, these studies establish a role for SIK1 in the positive regulation of selective HDL-CE transport function of SR-B1 and steroidogenesis and suggest a potential mechanism for SIK1 signaling in modulating SR-B1-mediated selective CE uptake and associated steroidogenesis.
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Affiliation(s)
- Zhigang Hu
- Geriatric Research, Education and Clinical Center, Veterans Affairs Palo Alto Health Care System , Palo Alto, California 94304, United States
| | - Jie Hu
- Geriatric Research, Education and Clinical Center, Veterans Affairs Palo Alto Health Care System , Palo Alto, California 94304, United States
| | - Wen-Jun Shen
- Geriatric Research, Education and Clinical Center, Veterans Affairs Palo Alto Health Care System , Palo Alto, California 94304, United States
| | - Fredric B Kraemer
- Geriatric Research, Education and Clinical Center, Veterans Affairs Palo Alto Health Care System , Palo Alto, California 94304, United States
| | - Salman Azhar
- Geriatric Research, Education and Clinical Center, Veterans Affairs Palo Alto Health Care System , Palo Alto, California 94304, United States
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14
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Hu H, Liu Y, Jiang T. Mutation-introduced dimerization of receptor tyrosine kinases: from protein structure aberrations to carcinogenesis. Tumour Biol 2015; 36:1423-8. [PMID: 25750036 DOI: 10.1007/s13277-015-3287-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 02/24/2015] [Indexed: 01/11/2023] Open
Abstract
Cancer is the greatest challenge to human health in our era. Perturbations of receptor tyrosine kinase (RTK) function contribute to a large chunk of cancer etiology. Current evidence supports that mutations in RTKs mediate receptor dimerization and result in ligand-independent kinase activity and tumorigenesis, indicating that mutation-introduced receptor dimerization is a critical component of oncogenesis RTK mutations. However, there are no specialized reviews of this important principle. In the current review, we discuss the physiological and harmless RTK function and subsequently examine mutation-introduced dimerization of RTKs and the role of these mutations in tumorigenesis. We also summarize the protein structure characteristics that are important for dimerization and introduce research methods and tools to predict and validate the existence of oncogenic mutations introduced by dimerization in RTKs.
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Affiliation(s)
- Huimin Hu
- Department of Molecular Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, No. 6 Tiantan Xili, Dongcheng, Beijing, 100050, People's Republic of China
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15
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Shen WJ, Hu J, Hu Z, Kraemer FB, Azhar S. Scavenger receptor class B type I (SR-BI): a versatile receptor with multiple functions and actions. Metabolism 2014; 63:875-86. [PMID: 24854385 PMCID: PMC8078058 DOI: 10.1016/j.metabol.2014.03.011] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 03/12/2014] [Accepted: 03/18/2014] [Indexed: 11/16/2022]
Abstract
Scavenger receptor class B type I (SR-BI), is a physiologically relevant HDL receptor that mediates selective uptake of lipoprotein (HDL)-derived cholesteryl ester (CE) in vitro and in vivo. Mammalian SR-BI is a 509-amino acid, ~82 kDa glycoprotein that contains N- and C-terminal cytoplasmic domains, two-transmembrane domains, as well as a large extracellular domain containing 5-6 cysteine residues and multiple sites for N-linked glycosylation. The size and structural characteristics of SR-BI, however, vary considerably among lower vertebrates and insects. Recently, significant progress has been made in understanding the molecular mechanisms involved in the posttranscriptional/posttranslational regulation of SR-BI in a tissue specific manner. The purpose of this review is to summarize the current body of knowledge about the events and molecules connected with the posttranscriptional/posttranslational regulation of SR-BI and to update the molecular and functional characteristics of the insect SR-BI orthologs.
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MESH Headings
- Animals
- Biological Transport
- Gene Expression Regulation
- Glycosylation
- Humans
- Insect Proteins/chemistry
- Insect Proteins/genetics
- Insect Proteins/metabolism
- Lipoproteins, HDL/chemistry
- Lipoproteins, HDL/genetics
- Lipoproteins, HDL/metabolism
- Liver/metabolism
- Organ Specificity
- Protein Conformation
- Protein Processing, Post-Translational
- Receptors, Lipoprotein/chemistry
- Receptors, Lipoprotein/genetics
- Receptors, Lipoprotein/metabolism
- Scavenger Receptors, Class B/chemistry
- Scavenger Receptors, Class B/genetics
- Scavenger Receptors, Class B/metabolism
- Species Specificity
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Affiliation(s)
- Wen-Jun Shen
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California 94304; Division of Endocrinology, Stanford University, Stanford, California 94305
| | - Jie Hu
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California 94304
| | - Zhigang Hu
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California 94304; Division of Endocrinology, Stanford University, Stanford, California 94305
| | - Fredric B Kraemer
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California 94304; Division of Endocrinology, Stanford University, Stanford, California 94305
| | - Salman Azhar
- Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, California 94304; Division of Gastroenterology and Hepatology, Stanford University, Stanford, California 94305.
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16
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Abstract
PURPOSE OF REVIEW Selective lipid uptake (SLU) is known to be a major pathway of lipoprotein cholesterol metabolism in experimental animals and humans, but remains poorly understood. This review provides a brief overview of SLU mediated by the HDL receptor scavenger receptor B-type I (SR-BI), and highlights several surprising new findings related to the impact of SLU pathways in cholesterol homeostasis. RECENT FINDINGS Under certain conditions, SR-BI-mediated SLU contributes to reverse cholesterol transport (RCT) independently of ABCG5/G8-mediated biliary cholesterol secretion, implying a novel trafficking mechanism. Hepatic SR-BI expression and RCT are decreased in diabetic mice. Farnesoid X receptor (FXR) and the microRNAs miR-185, miR-96 and miR-223 are emerging therapeutic targets for increasing SR-BI expression. SR-BI-independent selective cholesteryl ester uptake is a newly characterized pathway in macrophage foam cells. SUMMARY New findings underscore the importance of SR-BI-mediated SLU in hepatic SLU and RCT, while indicating that further investigation is needed to define SLU pathways, including SR-BI-independent macrophage selective cholesteryl ester uptake. The intracellular trafficking of cholesterol in these pathways appears to be critical to their normal function and is a major subject of ongoing studies.
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Affiliation(s)
- Jason M. Meyer
- Departments of Internal Medicine and Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, Kentucky, USA
| | - Gregory A. Graf
- Department Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky, USA
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, Kentucky, USA
- Barnstable Brown Kentucky Diabetes and Obesity Center, University of Kentucky, Lexington, Kentucky, USA
| | - Deneys R. van der Westhuyzen
- Department of Veterans Affairs Medical Center, University of Kentucky, Lexington, Kentucky, USA
- Departments of Internal Medicine and Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, Kentucky, USA
- Barnstable Brown Kentucky Diabetes and Obesity Center, University of Kentucky, Lexington, Kentucky, USA
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17
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Hu Z, Hu J, Zhang Z, Shen WJ, Yun CC, Berlot CH, Kraemer FB, Azhar S. Regulation of expression and function of scavenger receptor class B, type I (SR-BI) by Na+/H+ exchanger regulatory factors (NHERFs). J Biol Chem 2013; 288:11416-35. [PMID: 23482569 DOI: 10.1074/jbc.m112.437368] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Scavenger receptor class B, type I (SR-BI) binds HDL and mediates selective delivery of cholesteryl esters (CEs) to the liver, adrenals, and gonads for product formation (bile acids and steroids). Because relatively little is known about SR-BI posttranslational regulation in steroidogenic cells, we examined the roles of Na(+)/H(+) exchanger regulatory factors (NHERFs) in regulating SR-BI expression, SR-BI-mediated selective CE uptake, and steroidogenesis. NHERF1 and NHERF2 mRNA and protein are expressed at varying levels in model steroidogenic cell lines and the adrenal, with only low expression of PDZK1 (NHERF3) and NHERF4. Dibutyryl cyclic AMP decreased NHERF1 and NHERF2 and increased SR-BI mRNA expression in primary rat granulosa cells and MLTC-1 cells, whereas ACTH had no effect on NHERF1 and NHERF2 mRNA levels but decreased their protein levels in rat adrenals. Co-immunoprecipitation, colocalization, bimolecular fluorescence complementation, and mutational analysis indicated that SR-BI associates with NHERF1 and NHERF2. NHERF1 and NHERF2 down-regulated SR-BI protein expression through inhibition of its de novo synthesis. NHERF1 and NHERF2 also inhibited SR-BI-mediated selective CE transport and steroidogenesis, which were markedly attenuated by partial deletions of the PDZ1 or PDZ2 domain of NHERF1, the PDZ2 domain of NHERF2, or the MERM domains of NHERF1/2 or by gene silencing of NHERF1/2. Moreover, an intact COOH-terminal PDZ recognition motif (EAKL) in SR-BI is needed. Transient transfection of hepatic cell lines with NHERF1 or NHERF2 caused a significant reduction in endogenous protein levels of SR-BI. Collectively, these data establish NHERF1 and NHERF2 as SR-BI protein binding partners that play a negative role in the regulation of SR-BI expression, selective CE transport, and steroidogenesis.
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Affiliation(s)
- Zhigang Hu
- Geriatric Research, Education and Clinical Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304, USA
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18
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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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Sakudoh T, Kuwazaki S, Iizuka T, Narukawa J, Yamamoto K, Uchino K, Sezutsu H, Banno Y, Tsuchida K. CD36 homolog divergence is responsible for the selectivity of carotenoid species migration to the silk gland of the silkworm Bombyx mori. J Lipid Res 2012; 54:482-95. [PMID: 23160179 DOI: 10.1194/jlr.m032771] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Dietary carotenoids are absorbed in the intestine and delivered to various tissues by circulating lipoproteins; however, the mechanism underlying selective delivery of different carotenoid species to individual tissues remains elusive. The products of the Yellow cocoon (C) gene and the Flesh (F) gene of the silkworm Bombyx mori determine the selectivity for transport of lutein and β-carotene, respectively, to the silk gland. We previously showed that the C gene encodes Cameo2, a CD36 family member, which is thought to function as a transmembrane lipoprotein receptor. Here, we elucidated the molecular identity of the F gene product by positional cloning, as SCRB15, a paralog of Cameo2 with 26% amino acid identity. In the F mutant, SCRB15 mRNA structure was severely disrupted, due to a 1.4 kb genomic insertion in a coding exon. Transgenic expression of SCRB15 in the middle silk gland using the binary GAL4-UAS expression system enhanced selective β-carotene uptake by the middle silk gland, while transgenic expression of Cameo2 enhanced selective lutein uptake under the same GAL4 driver. Our findings indicate that divergence of genes in the CD36 family determines the selectivity of carotenoid species uptake by silk gland tissue and that CD36-homologous proteins can discriminate among carotenoid species.
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Affiliation(s)
- Takashi Sakudoh
- Division of Radiological Protection and Biology, National Institute of Infectious Diseases, Shinjuku Tokyo 162-8640, Japan.
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20
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Redox regulation of cysteine-dependent enzymes in neurodegeneration. Int J Cell Biol 2012; 2012:703164. [PMID: 22829832 PMCID: PMC3398591 DOI: 10.1155/2012/703164] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 05/10/2012] [Indexed: 11/17/2022] Open
Abstract
Evidence of increased oxidative stress has been found in various neurodegenerative diseases and conditions. While it is unclear whether oxidative stress is a cause or effect, protein, lipid, and DNA have all been found to be susceptible to oxidant-induced modifications that alter their function. Results of clinical trials based on the oxidative-stress theory have been mixed, though data continues to indicate that prevention of high levels of oxidative stress is beneficial for health and increases longevity. Due to the highly reactive nature of the sulfhydryl group, the focus of this paper is on the impact of oxidative stress on cysteine-dependent enzymes and how oxidative stress may contribute to neurological dysfunction through this selected group of proteins.
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