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Zhou L, Ji S, Xue R, Tian Z, Wei M, Yuan X, Sun J, Ji H. Comparative analysis of Scarb1 and Cd36 in grass carp (Ctenopharyngodon idellus): Implications for DHA uptake. Comp Biochem Physiol B Biochem Mol Biol 2024; 275:111025. [PMID: 39181181 DOI: 10.1016/j.cbpb.2024.111025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2024] [Revised: 08/20/2024] [Accepted: 08/21/2024] [Indexed: 08/27/2024]
Abstract
The polyunsaturated fatty acid docosahexaenoic acid (DHA) significantly influences fish growth and lipid metabolism. Nevertheless, the specific mechanism by which DHA is transported and exerts its effects remains unclear. Scavenger receptor class B type I (SCARB1) is essential for maintaining cellular cholesterol levels and regulating the immune system in mammals, as well as facilitating the uptake of fatty acids (FAs). Another class B scavenger receptor, cluster-determinant 36 (CD36), is involved in promoting the uptake and transport of long-chain fatty acids. However, the molecular characteristics of the grass carp scarb1 gene have not yet been reported, and the potential role of Scarb1 and Cd36 in mediating DHA transport and metabolism remains uncertain. This study aimed to investigate the effects of Scarb1 and Cd36 on DHA transport. Initially, grass carp scarb1-1 and scarb1-2 were cloned. Predictions were made regarding their structural characteristics, including number and presence of transmembrane domains and glycosylation sites. Furthermore, gene structure analysis revealed that scarb1-1 has two additional exons in the 3'-region compared to scarb1-2. The multiple sequence alignment indicated that Scarb1 exhibits conserved motifs and amino acid residues across vertebrates. mRNA expression of scarb1-1 was the highest in the intestine, while scarb1-2 was highest expressed in adipose tissue, with both having lower expression levels in muscle tissue. Scarb1-1 was primarily localized on the cell membrane, whereas Scarb1-2 was found in both the cell membrane and cytoplasm. After overexpression of grass carp Scarb1-1, Scarb1-2, and Cd36 in HEK 293 T cells, DHA incubation showed that only Cd36 significantly increased cellular DHA relative content, suggesting a potential role of Cd36 in DHA transport. These findings will serve as a basis for further research on fatty acid transport in fish.
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Affiliation(s)
- Lu Zhou
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, PR China
| | - Shanghong Ji
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, PR China
| | - Rongrong Xue
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, PR China
| | - Zhiqi Tian
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, PR China
| | - Mingkui Wei
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, PR China
| | - Xiangtong Yuan
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, PR China
| | - Jian Sun
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, PR China
| | - Hong Ji
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, PR China.
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Hu K, Onintsoa Diarimalala R, Yao C, Li H, Wei Y. EV-A71 Mechanism of Entry: Receptors/Co-Receptors, Related Pathways and Inhibitors. Viruses 2023; 15:785. [PMID: 36992493 PMCID: PMC10051052 DOI: 10.3390/v15030785] [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: 12/12/2022] [Revised: 03/08/2023] [Accepted: 03/14/2023] [Indexed: 03/31/2023] Open
Abstract
Enterovirus A71, a non-enveloped single-stranded (+) RNA virus, enters host cells through three stages: attachment, endocytosis and uncoating. In recent years, receptors/co-receptors anchored on the host cell membrane and involved in this process have been continuously identified. Among these, hSCARB-2 was the first receptor revealed to specifically bind to a definite site of the EV-A71 viral capsid and plays an indispensable role during viral entry. It actually acts as the main receptor due to its ability to recognize all EV-A71 strains. In addition, PSGL-1 is the second EV-A71 receptor discovered. Unlike hSCARB-2, PSGL-1 binding is strain-specific; only 20% of EV-A71 strains isolated to date are able to recognize and bind it. Some other receptors, such as sialylated glycan, Anx 2, HS, HSP90, vimentin, nucleolin and fibronectin, were discovered successively and considered as "co-receptors" because, without hSCARB-2 or PSGL-1, they are not able to mediate entry. For cypA, prohibitin and hWARS, whether they belong to the category of receptors or of co-receptors still needs further investigation. In fact, they have shown to exhibit an hSCARB-2-independent entry. All this information has gradually enriched our knowledge of EV-A71's early stages of infection. In addition to the availability of receptors/co-receptors for EV-A71 on host cells, the complex interaction between the virus and host proteins and various intracellular signaling pathways that are intricately connected to each other is critical for a successful EV-A71 invasion and for escaping the attack of the immune system. However, a lot remains unknown about the EV-A71 entry process. Nevertheless, researchers have been continuously interested in developing EV-A71 entry inhibitors, as this study area offers a large number of targets. To date, important progress has been made toward the development of several inhibitors targeting: receptors/co-receptors, including their soluble forms and chemically designed compounds; virus capsids, such as capsid inhibitors designed on the VP1 capsid; compounds potentially interfering with related signaling pathways, such as MAPK-, IFN- and ATR-inhibitors; and other strategies, such as siRNA and monoclonal antibodies targeting entry. The present review summarizes these latest studies, which are undoubtedly of great significance in developing a novel therapeutic approach against EV-A71.
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Affiliation(s)
| | | | | | | | - Yanhong Wei
- Sino-German Biomedical Center, National “111” Center for Cellular Regulation and Molecular Pharmaceutics, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei University of Technology, Wuhan 430068, China; (K.H.); (R.O.D.); (C.Y.); (H.L.)
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Toll-Like Receptors: General Molecular and Structural Biology. J Immunol Res 2021; 2021:9914854. [PMID: 34195298 PMCID: PMC8181103 DOI: 10.1155/2021/9914854] [Citation(s) in RCA: 97] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/19/2021] [Indexed: 12/11/2022] Open
Abstract
Background/Aim Toll-like receptors (TLRs) are pivotal biomolecules in the immune system. Today, we are all aware of the importance of TLRs in bridging innate and adaptive immune system to each other. The TLRs are activated through binding to damage/danger-associated molecular patterns (DAMPs), microbial/microbe-associated molecular patterns (MAMPs), pathogen-associated molecular patterns (PAMPs), and xenobiotic-associated molecular patterns (XAMPs). The immunogenetic molecules of TLRs have their own functions, structures, coreceptors, and ligands which make them unique. These properties of TLRs give us an opportunity to find out how we can employ this knowledge for ligand-drug discovery strategies to control TLRs functions and contribution, signaling pathways, and indirect activities. Hence, the authors of this paper have a deep observation on the molecular and structural biology of human TLRs (hTLRs). Methods and Materials To prepare this paper and fulfill our goals, different search engines (e.g., GOOGLE SCHOLAR), Databases (e.g., MEDLINE), and websites (e.g., SCOPUS) were recruited to search and find effective papers and investigations. To reach this purpose, we tried with papers published in the English language with no limitation in time. The iCite bibliometrics was exploited to check the quality of the collected publications. Results Each TLR molecule has its own molecular and structural biology, coreceptor(s), and abilities which make them unique or a complementary portion of the others. These immunogenetic molecules have remarkable roles and are much more important in different sections of immune and nonimmune systems rather than that we understand to date. Conclusion TLRs are suitable targets for ligand-drug discovery strategies to establish new therapeutics in the fields of infectious and autoimmune diseases, cancers, and other inflammatory diseases and disorders.
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Tee HK, Zainol MI, Sam IC, Chan YF. Recent advances in the understanding of enterovirus A71 infection: a focus on neuropathogenesis. Expert Rev Anti Infect Ther 2021; 19:733-747. [PMID: 33183118 DOI: 10.1080/14787210.2021.1851194] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Introduction: Hand, foot, and mouth disease caused by enterovirus A71 (EV-A71) is more frequently associated with neurological complications and deaths compared to other enteroviruses.Areas covered: The authors discuss current understanding of the neuropathogenesis of EV-A71 based on various clinical, human, and animal model studies. The authors discuss the important advancements in virus entry, virus dissemination, and neuroinvasion. The authors highlight the role of host immune system, host genetic factors, viral quasispecies, and heparan sulfate in EV-A71 neuropathogenesis.Expert opinion: Comparison of EV-A71 with EV-D68 and PV shows similarity in primary target sites and dissemination to the central nervous system. More research is needed to understand cellular tropisms, persistence of EV-A71, and other possible invasion routes. EV-A71 infection has varied clinical manifestations which may be attributed to multiple receptors usage. Future development of antivirals and vaccines should target neurotropic enteroviruses. Repurposing drug and immunomodulators used in combination could reduce the severity of EV-A71 infection. Only a few drugs have been tested in clinical trials, and in the absence of antiviral and vaccines (except China), active virus surveillance, good hand hygiene, and physical distancing should be advocated. A better understanding of EV-A71 neuropathogenesis is critical for antiviral and multivalent vaccines development.
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Affiliation(s)
- Han Kang Tee
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Mohd Izwan Zainol
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - I-Ching Sam
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Yoke Fun Chan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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Gąsecka A, Rogula S, Szarpak Ł, Filipiak KJ. LDL-Cholesterol and Platelets: Insights into Their Interactions in Atherosclerosis. Life (Basel) 2021; 11:39. [PMID: 33440673 PMCID: PMC7826814 DOI: 10.3390/life11010039] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 01/06/2021] [Accepted: 01/07/2021] [Indexed: 12/23/2022] Open
Abstract
Atherosclerosis and its complications, including acute coronary syndromes, are the major cause of death worldwide. The two most important pathophysiological mechanisms underlying atherosclerosis include increased platelet activation and increased low-density lipoproteins (LDL) concentration. In contrast to LDL, oxidized (ox)-LDL have direct pro-thrombotic properties by functional interactions with platelets, leading to platelet activation and favoring thrombus formation. In this review, we summarize the currently available evidence on the interactions between LDL-cholesterol and platelets, which are based on (i) the presence of ox-LDL-binding sites on platelets, (ii) generation of ox-LDL by platelets and (iii) the role of activated platelets and ox-LDL in atherosclerosis. In addition, we elaborate on the clinical implications of these interactions, including development of the new therapeutic possibilities. The ability to understand and modulate mechanisms governing interactions between LDL-cholesterol and platelets may offer new treatment strategies for atherosclerosis prevention.
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Affiliation(s)
- Aleksandra Gąsecka
- Department of Cardiology, Medical University of Warsaw, 02-091 Warsaw, Poland; (S.R.); (K.J.F.)
| | - Sylwester Rogula
- Department of Cardiology, Medical University of Warsaw, 02-091 Warsaw, Poland; (S.R.); (K.J.F.)
| | - Łukasz Szarpak
- Bialystok Oncology Center, 15-027, Bialystok, Poland;
- Maria Sklodowska-Curie Medical Academy in Warsaw, 03-411 Warsaw, Poland
| | - Krzysztof J. Filipiak
- Department of Cardiology, Medical University of Warsaw, 02-091 Warsaw, Poland; (S.R.); (K.J.F.)
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Chandra NC. Atherosclerosis and carcinoma: Two facets of dysfunctional cholesterol homeostasis. J Biochem Mol Toxicol 2020; 34:e22595. [PMID: 32761975 DOI: 10.1002/jbt.22595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 07/04/2020] [Accepted: 07/23/2020] [Indexed: 12/11/2022]
Abstract
Although cholesterol is an essential and necessary component for biological systems; inappropriate accumulation of cholesterol in blood vessels and intracellular territory is also detrimental to living things. On one hand, cholesterol is the acting precursor of many metabolic regulators, a component of the structural veracity and scaffold fluidity of biomembranes, an insulator of electrical transmission in nerves and many more; on the other hand, its deposition in blood vessels induces atherosclerotic plaque and cardiovascular complications with the consequences of heart attack and stroke. It is also an emerging fact that cholesterol is a prelate in the cell nucleus for cell proliferation and any oddity in this venture may be the cause of tumorigenesis. Hence, cholesterol homeostasis is a very crucial element in issues of health management. Cholesterol is now a global target for maintaining quality health, particularly to control the two giants of the present world health tragedy: atherosclerosis and carcinoma, which appear to be the two facets of dysfunctional cholesterol homeostasis.
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Affiliation(s)
- Nimai C Chandra
- Department of Biochemistry, All India Institute of Medical Sciences, Patna, India
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Abstract
Enterovirus 71 (EV-A71) is one of the major causative agents of hand, foot, and mouth disease. EV-A71 infection is sometimes associated with severe neurological diseases such as acute encephalitis, acute flaccid paralysis, and cardiopulmonary failure. Therefore, EV-A71 is a serious public health concern. Scavenger receptor class B, member 2 (SCARB2) is a type III transmembrane protein that belongs to the CD36 family and is a major receptor for EV-A71. SCARB2 supports attachment and internalization of the virus and initiates conformational changes that lead to uncoating of viral RNA in the cytoplasm. The three-dimensional structure of the virus-receptor complex was elucidated by cryo-electron microscopy. Two α-helices in the head domain of SCARB2 bind to the G-H loop of VP1 and the E-F loop of VP2 capsid proteins of EV-A71. Uncoating takes place in a SCARB2- and low pH-dependent manner. In addition to SCARB2, other molecules support cell surface binding of EV-A71. Heparan sulfate proteoglycans, P-selectin glycoprotein ligand-1, sialylated glycan, annexin II, vimentin, fibronectin, and prohibitin enhance viral infection by retaining the virus on the cell surface. These molecules are known as “attachment receptors” because they cannot initiate uncoating. In vivo, SCARB2 expression was observed in EV-A71 antigen-positive neurons and epithelial cells in the crypts of the palatine tonsils in patients that died of EV-A71 infection. Adult mice are not susceptible to infection by EV-A71, but transgenic mice that express human SCARB2 become susceptible to EV-A71 infection and develop neurological diseases similar to those observed in humans. Attachment receptors may also be involved in EV-A71 infection in vivo. Although heparan sulfate proteoglycans are expressed by many cultured cell lines and enhance infection by a subset of EV-A71 strains, they are not expressed by cells that express SCARB2 at high levels in vivo. Thus, heparan sulfate-positive cells merely adsorb the virus and do not contribute to replication or dissemination of the virus in vivo. In addition to these attachment receptors, cyclophilin A and human tryptophanyl aminoacyl-tRNA synthetase act as an uncoating regulator and an entry mediator that can confer susceptibility to non-susceptibile cells in the absence of SCARB2, respectively. The roles of attachment receptors and other molecules in EV-A71 pathogenesis remain to be elucidated.
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Affiliation(s)
- Kyousuke Kobayashi
- Neurovirology Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan
| | - Satoshi Koike
- Neurovirology Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan.
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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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Che Z, Shao Y, Zhang W, Zhao X, Guo M, Li C. Cloning and functional analysis of scavenger receptor B gene from the sea cucumber Apostichopus japonicus. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2019; 99:103404. [PMID: 31152761 DOI: 10.1016/j.dci.2019.103404] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/23/2019] [Accepted: 05/25/2019] [Indexed: 06/09/2023]
Abstract
Scavenger receptor (SR) class B (SR-B) is a transmembrane protein that belongs to the SR family with a wide range of functions in innate immunity. Here, an SR-B homologue, designated as AjSR-B, was cloned from the sea cucumber Apostichopus japonicus. AjSR-B comprised 2519 nucleotides with a 5'-untranslated region (UTR) of 153 bp, an open reading frame of 1581 bp encoding a 526 amino acid protein, and a 3'-UTR of 785 bp. SMART analysis indicated that AjSR-B has two transmembrane regions and a cluster determinant 36 domain. Multiple alignments and phylogenetic analysis supported that AjSR-B is a novel member of the SR-B protein family. Moreover, AjSR-B was constitutively expressed in all detected tissues, with the highest levels recorded in the intestine. Both were significantly induced in coelomocytes and the intestine after Vibrio splendidus challenge. Functionally, the recombinant rAjSR-B that corresponds to a large extracellular loop can bind pathogen-associated molecular patterns (PAMPs), including lipopolysaccharide (LPS), peptidoglycan, and mannan, with a high binding affinity to LPS. Bacterial agglutination assay showed that rAjSR-B can agglutinate the four tested bacteria (Gram-negative and Gram-positive bacteria) with calcium dependence. However, the agglutination ability for Gram-negative bacteria completely disappeared in the presence of PAMPs but a weak ability to bind Gram-positive bacteria (Micrococcus luteus) was still exhibited, suggesting there might exist a competition between Gram-positive bacteria and PAMPs under same condition. Our current study indicated that AjSR-B is a PAMP that plays important roles in the innate immune process of sea cucumbers.
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Affiliation(s)
- Zhongjie Che
- School of Marine Sciences, Ningbo University, Ningbo, 315211, PR China
| | - Yina Shao
- School of Marine Sciences, Ningbo University, Ningbo, 315211, PR China
| | - Weiwei Zhang
- School of Marine Sciences, Ningbo University, Ningbo, 315211, PR China
| | - Xuelin Zhao
- School of Marine Sciences, Ningbo University, Ningbo, 315211, PR China
| | - Ming Guo
- School of Marine Sciences, Ningbo University, Ningbo, 315211, PR China
| | - Chenghua Li
- School of Marine Sciences, Ningbo University, Ningbo, 315211, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, PR China.
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Zhou D, Zhao Y, Kotecha A, Fry EE, Kelly JT, Wang X, Rao Z, Rowlands DJ, Ren J, Stuart DI. Unexpected mode of engagement between enterovirus 71 and its receptor SCARB2. Nat Microbiol 2019; 4:414-419. [PMID: 30531980 DOI: 10.1038/s41564-018-0319-z] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 11/09/2018] [Indexed: 11/09/2022]
Abstract
Enterovirus 71 (EV71) is a common cause of hand, foot and mouth disease-a disease endemic especially in the Asia-Pacific region1. Scavenger receptor class B member 2 (SCARB2) is the major receptor of EV71, as well as several other enteroviruses responsible for hand, foot and mouth disease, and plays a key role in cell entry2. The isolated structures of EV71 and SCARB2 are known3-6, but how they interact to initiate infection is not. Here, we report the EV71-SCARB2 complex structure determined at 3.4 Å resolution using cryo-electron microscopy. This reveals that SCARB2 binds EV71 on the southern rim of the canyon, rather than across the canyon, as predicted3,7,8. Helices 152-163 (α5) and 183-193 (α7) of SCARB2 and the viral protein 1 (VP1) GH and VP2 EF loops of EV71 dominate the interaction, suggesting an allosteric mechanism by which receptor binding might facilitate the low-pH uncoating of the virus in the endosome/lysosome. Remarkably, many residues within the binding footprint are not conserved across SCARB2-dependent enteroviruses; however, a conserved proline and glycine seem to be key residues. Thus, although the virus maintains antigenic variability even within the receptor-binding footprint, the identification of binding 'hot spots' may facilitate the design of receptor mimic therapeutics less likely to quickly generate resistance.
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Affiliation(s)
- Daming Zhou
- Division of Structural Biology, The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Yuguang Zhao
- Division of Structural Biology, The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Abhay Kotecha
- Division of Structural Biology, The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- Materials and Structural Analysis, Thermo Fisher Scientific, Eindhoven, the Netherlands
| | - Elizabeth E Fry
- Division of Structural Biology, The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - James T Kelly
- School of Molecular and Cellular Biology, Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
- The Pirbright Institute, Pirbright, UK
| | - Xiangxi Wang
- National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing, China
| | - Zihe Rao
- National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing, China
| | - David J Rowlands
- School of Molecular and Cellular Biology, Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Jingshan Ren
- Division of Structural Biology, The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
| | - David I Stuart
- Division of Structural Biology, The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
- Diamond Light Source, Didcot, UK.
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Yen TY, Shih WL, Huang YC, Lee JT, Huang LM, Chang LY. Polymorphisms in enterovirus 71 receptors associated with susceptibility and clinical severity. PLoS One 2018; 13:e0206769. [PMID: 30395634 PMCID: PMC6218064 DOI: 10.1371/journal.pone.0206769] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/18/2018] [Indexed: 01/05/2023] Open
Abstract
OBJECTIVE To evaluate the association of enterovirus 71 (EV71) susceptibility and clinical severity with polymorphisms in EV71 receptors, including human scavenger receptor class B member 2 (SCARB2), P-selectin glycoprotein ligand-1 (PSGL-1), and annexin II (ANXA2). METHODS We enrolled laboratory-confirmed EV71 cases and healthy age- and gender-matched controls in Taiwan from 2000 to 2012. We detected genetic polymorphisms in SCARB2, PSGL-1, and ANXA2 and correlated the results with EV71 susceptibility and severity. RESULTS We collected 599 EV71 cases and 98 controls. Among EV71 patients, the male to female ratio was 1.61, and the mean age was 2.99±2.47 years. For clinical severity, 117 (19.6%) had severe central nervous system involvement with or without cardiopulmonary failure. For outcomes, 46 (7.7%) had sequelae, and 14 (2.3%) died. SCARB2 polymorphisms (rs6824953 and rs11097262) were associated with susceptibility to EV71 infection (OR 1.60, 95% CI 1.07-2.39; and OR 1.64, 95% CI 1.09-2.47, respectively). PSGL-1 polymorphisms (rs7137098 and rs8179137) were significantly associated with severe EV71 infection (OR 1.46, 95% CI 1.1-1.96; and OR 1.47, 95% CI 1.07-2.03, respectively). CONCLUSIONS SCARB2 polymorphisms (rs6824953 and rs11097262) might be associated with EV71 susceptibility. PSGL-1 polymorphisms (rs7137098 and rs8179137) were associated with severe EV71 infection.
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Affiliation(s)
- Ting-Yu Yen
- Department of Pediatrics, China Medical University Children’s Hospital, China Medical University, Taichung, Taiwan
| | - Wei-Liang Shih
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Yi-Chuan Huang
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Jian-Te Lee
- Department of Pediatrics, National Taiwan University Hospital, Yun-Lin Branch, Yunlin, Taiwan
| | - Li-Min Huang
- Department of Pediatrics, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Luan-Yin Chang
- Department of Pediatrics, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
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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: 83] [Impact Index Per Article: 13.8] [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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13
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Yang N, Zhang DF, Tao Z, Li M, Zhou SM, Wang GL. Identification of a novel class B scavenger receptor homologue in Portunus trituberculatus: Molecular cloning and microbial ligand binding. FISH & SHELLFISH IMMUNOLOGY 2016; 58:73-81. [PMID: 27633673 DOI: 10.1016/j.fsi.2016.09.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 09/02/2016] [Accepted: 09/11/2016] [Indexed: 06/06/2023]
Abstract
Class B scavenger receptors (SRBs), which are present in mammals and insects, have been implicated in a wide range of functions. Herein, a novel SRB homologue, PtSRB, was cloned from the swimming crab, Portunus trituberculatus. PtSRB has 538 amino acid residues, and it consists of two transmembrane regions, a large extracellular loop, and two intracellular tails. A phylogenetic analysis showed that PtSRB distinctly clustered with Marsupenaeus japonicas SRB-1 and most Drosophila SRB homologues, including Croquemort, Peste, NinaD, and Santa Maria, but was separate from the Drosophila sensory neuron membrane protein, MjSRB-2, and all vertebrate SRBs. Real-time quantitative PCR analyses showed that the PtSRB gene was constitutively expressed in all tissues tested. When PtSRB was overexpressed in human embryonic kidney 293T cells, it was distributed in the membrane and cytoplasm. Moreover, in vitro assays showed that rPtSRB bound microbial lipopolysaccharide with low affinity, and lipoteichoic acid and peptidoglycan with high affinity. PtSRB transcripts were down-regulated after challenge with Vibrio alginolyticus or white spot syndrome virus, but not after a Candida lusitaniae challenge. This study provides valuable data for understanding the role of SRBs in the host defense against microbial pathogens, which will facilitate future studies of host-pathogen interactions in crabs.
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Affiliation(s)
- Ning Yang
- Key Laboratory of the Ministry of Education for Applied Marine Biotechnology, School of Marine Science, Ningbo University, Ningbo 315211, China; Marine Science and Engineering College, Qingdao Agricultural University, Qingdao 266109, China
| | - Dan-Feng Zhang
- Key Laboratory of the Ministry of Education for Applied Marine Biotechnology, School of Marine Science, Ningbo University, Ningbo 315211, China
| | - Zhen Tao
- Key Laboratory of the Ministry of Education for Applied Marine Biotechnology, School of Marine Science, Ningbo University, Ningbo 315211, China
| | - Meng Li
- Key Laboratory of the Ministry of Education for Applied Marine Biotechnology, School of Marine Science, Ningbo University, Ningbo 315211, China
| | - Su-Ming Zhou
- Key Laboratory of the Ministry of Education for Applied Marine Biotechnology, School of Marine Science, Ningbo University, Ningbo 315211, China.
| | - Guo-Liang Wang
- Key Laboratory of the Ministry of Education for Applied Marine Biotechnology, School of Marine Science, Ningbo University, Ningbo 315211, China.
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14
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Gutierrez-Pajares JL, Ben Hassen C, Chevalier S, Frank PG. SR-BI: Linking Cholesterol and Lipoprotein Metabolism with Breast and Prostate Cancer. Front Pharmacol 2016; 7:338. [PMID: 27774064 PMCID: PMC5054001 DOI: 10.3389/fphar.2016.00338] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/12/2016] [Indexed: 12/16/2022] Open
Abstract
Studies have demonstrated the significant role of cholesterol and lipoprotein metabolism in the progression of cancer. The SCARB1 gene encodes the scavenger receptor class B type I (SR-BI), which is an 82-kDa glycoprotein with two transmembrane domains separated by a large extracellular loop. SR-BI plays an important role in the regulation of cholesterol exchange between cells and high-density lipoproteins. Accordingly, hepatic SR-BI has been shown to play an essential role in the regulation of the reverse cholesterol transport pathway, which promotes the removal and excretion of excess body cholesterol. In the context of atherosclerosis, SR-BI has been implicated in the regulation of intracellular signaling, lipid accumulation, foam cell formation, and cellular apoptosis. Furthermore, since lipid metabolism is a relevant target for cancer treatment, recent studies have focused on examining the role of SR-BI in this pathology. While signaling pathways have initially been explored in non-tumoral cells, studies with cancer cells have now demonstrated SR-BI's function in tumor progression. In this review, we will discuss the role of SR-BI during tumor development and malignant progression. In addition, we will provide insights into the transcriptional and post-transcriptional regulation of the SCARB1 gene. Overall, studying the role of SR-BI in tumor development and progression should allow us to gain useful information for the development of new therapeutic strategies.
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Affiliation(s)
- Jorge L Gutierrez-Pajares
- Université François Rabelais de Tours, Faculté de Médecine-INSERM UMR1069 "Nutrition, Croissance et Cancer" Tours, France
| | - Céline Ben Hassen
- Université François Rabelais de Tours, Faculté de Médecine-INSERM UMR1069 "Nutrition, Croissance et Cancer" Tours, France
| | - Stéphan Chevalier
- Université François Rabelais de Tours, Faculté de Médecine-INSERM UMR1069 "Nutrition, Croissance et Cancer" Tours, France
| | - Philippe G Frank
- Université François Rabelais de Tours, Faculté de Médecine-INSERM UMR1069 "Nutrition, Croissance et Cancer" Tours, France
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15
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Dibbens L, Schwake M, Saftig P, Rubboli G. SCARB2/LIMP2 deficiency in action myoclonus-renal failure syndrome. Epileptic Disord 2016; 18:63-72. [PMID: 27582254 DOI: 10.1684/epd.2016.0843] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Action myoclonus-renal failure syndrome (AMRF) is an autosomal recessive progressive myoclonus epilepsy (PME) associated with renal dysfunction that appears in the second or third decade of life and that is caused by loss-of-function mutations in the SCARB2 gene encoding lysosomal integral membrane protein type 2 (LIMP2). Recent reports have documented cases with PME associated with SCARB2 mutations without renal compromise. Additional neurological features can be demyelinating peripheral neuropathy, hearing loss and dementia. The course of the disease in relentlessly progressive. In this paper we provide an updated overview of the clinical and genetic features of SCARB2-related PME and on the functions of the LIMP2 protein.
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Affiliation(s)
- Leanne Dibbens
- Epilepsy Research Group, School of Pharmacy and Medical Sciences, University of South Australia, and Sansom Institute for Health Research, South Australia, Australia
| | | | - Paul Saftig
- Biochemical Institute, Christian-Albrechts-University Kiel, Germany
| | - Guido Rubboli
- Danish Epilepsy Center, Filadelfia/University of Copenhagen, Dianalund, Denmark, IRCCS, Institute of Neurologicak Sciences, Bellaria Hospital, Bologna, Italy
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16
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Zhang J, Zu Y, Dhanasekara CS, Li J, Wu D, Fan Z, Wang S. Detection and treatment of atherosclerosis using nanoparticles. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2016; 9. [PMID: 27241794 DOI: 10.1002/wnan.1412] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 03/25/2016] [Accepted: 04/12/2016] [Indexed: 01/10/2023]
Abstract
Atherosclerosis is the key pathogenesis of cardiovascular disease, which is a silent killer and a leading cause of death in the United States. Atherosclerosis starts with the adhesion of inflammatory monocytes on the activated endothelial cells in response to inflammatory stimuli. These monocytes can further migrate into the intimal layer of the blood vessel where they differentiate into macrophages, which take up oxidized low-density lipoproteins and release inflammatory factors to amplify the local inflammatory response. After accumulation of cholesterol, the lipid-laden macrophages are transformed into foam cells, the hallmark of the early stage of atherosclerosis. Foam cells can die from apoptosis or necrosis, and the intracellular lipid is deposed in the artery wall forming lesions. The angiogenesis for nurturing cells is enhanced during lesion development. Proteases released from macrophages, foam cells, and other cells degrade the fibrous cap of the lesion, resulting in rupture of the lesion and subsequent thrombus formation. Thrombi can block blood circulation, which represents a major cause of acute heart events and stroke. There are generally no symptoms in the early stages of atherosclerosis. Current detection techniques cannot easily, safely, and effectively detect the lesions in the early stages, nor can they characterize the lesion features such as the vulnerability. While the available therapeutic modalities cannot target specific molecules, cells, and processes in the lesions, nanoparticles appear to have a promising potential in improving atherosclerosis detection and treatment via targeting the intimal macrophages, foam cells, endothelial cells, angiogenesis, proteolysis, apoptosis, and thrombosis. Indeed, many nanoparticles have been developed in improving blood lipid profile and decreasing inflammatory response for enhancing therapeutic efficacy of drugs and decreasing their side effects. WIREs Nanomed Nanobiotechnol 2017, 9:e1412. doi: 10.1002/wnan.1412 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Jia Zhang
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX, USA
| | - Yujiao Zu
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX, USA
| | | | - Jun Li
- Laboratory Animal Center, Peking University, Beijing, PR China
| | - Dayong Wu
- Nutritional Immunology Laboratory, Jean Mayer Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
| | - Zhaoyang Fan
- Department of Electrical and Computer Engineering and Nano Tech Center, Texas Tech University, Lubbock, TX, USA
| | - Shu Wang
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX, USA
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17
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Jeanne A, Schneider C, Martiny L, Dedieu S. Original insights on thrombospondin-1-related antireceptor strategies in cancer. Front Pharmacol 2015; 6:252. [PMID: 26578962 PMCID: PMC4625054 DOI: 10.3389/fphar.2015.00252] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/15/2015] [Indexed: 01/04/2023] Open
Abstract
Thrombospondin-1 (TSP-1) is a large matricellular glycoprotein known to be overexpressed within tumor stroma in several cancer types. While mainly considered as an endogenous angiogenesis inhibitor, TSP-1 exhibits multifaceted functionalities in a tumor context depending both on TSP-1 concentration as well as differential receptor expression by cancer cells and on tumor-associated stromal cells. Besides, the complex modular structure of TSP-1 along with the wide variety of its soluble ligands and membrane receptors considerably increases the complexity of therapeutically targeting interactions involving TSP-1 ligation of cell-surface receptors. Despite the pleiotropic nature of TSP-1, many different antireceptor strategies have been developed giving promising results in preclinical models. However, transition to clinical trials often led to nuanced outcomes mainly due to frequent severe adverse effects. In this review, we will first expose the intricate and even sometimes opposite effects of TSP-1-related signaling on tumor progression by paying particular attention to modulation of angiogenesis and tumor immunity. Then, we will provide an overview of current developments and prospects by focusing particularly on the cell-surface molecules CD47 and CD36 that function as TSP-1 receptors; including antibody-based approaches, therapeutic gene modulation and the use of peptidomimetics. Finally, we will discuss original approaches specifically targeting TSP-1 domains, as well as innovative combination strategies with a view to producing an overall anticancer response.
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Affiliation(s)
- Albin Jeanne
- Laboratoire SiRMa, UFR Sciences Exactes et Naturelles, Université de Reims Champagne-Ardenne Reims, France ; CNRS, Matrice Extracellulaire et Dynamique Cellulaire, UMR 7369 Reims, France ; SATT Nord Lille, France
| | - Christophe Schneider
- Laboratoire SiRMa, UFR Sciences Exactes et Naturelles, Université de Reims Champagne-Ardenne Reims, France ; CNRS, Matrice Extracellulaire et Dynamique Cellulaire, UMR 7369 Reims, France
| | - Laurent Martiny
- Laboratoire SiRMa, UFR Sciences Exactes et Naturelles, Université de Reims Champagne-Ardenne Reims, France ; CNRS, Matrice Extracellulaire et Dynamique Cellulaire, UMR 7369 Reims, France
| | - Stéphane Dedieu
- Laboratoire SiRMa, UFR Sciences Exactes et Naturelles, Université de Reims Champagne-Ardenne Reims, France ; CNRS, Matrice Extracellulaire et Dynamique Cellulaire, UMR 7369 Reims, France
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18
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Yazdekhasti N, Brandsch C, Schmidt N, Schloesser A, Huebbe P, Rimbach G, Stangl GI. Fish protein increases circulating levels of trimethylamine-N
-oxide and accelerates aortic lesion formation in apoE null mice. Mol Nutr Food Res 2015; 60:358-68. [DOI: 10.1002/mnfr.201500537] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 09/21/2015] [Accepted: 09/25/2015] [Indexed: 11/05/2022]
Affiliation(s)
- Narges Yazdekhasti
- Institute of Agricultural and Nutritional Sciences; Martin Luther University Halle-Wittenberg; Halle/Saale Germany
| | - Corinna Brandsch
- Institute of Agricultural and Nutritional Sciences; Martin Luther University Halle-Wittenberg; Halle/Saale Germany
| | - Nadine Schmidt
- Institute of Agricultural and Nutritional Sciences; Martin Luther University Halle-Wittenberg; Halle/Saale Germany
| | - Anke Schloesser
- Institute of Human Nutrition and Food Science; University of Kiel; Kiel Germany
| | - Patricia Huebbe
- Institute of Human Nutrition and Food Science; University of Kiel; Kiel Germany
| | - Gerald Rimbach
- Institute of Human Nutrition and Food Science; University of Kiel; Kiel Germany
| | - Gabriele I. Stangl
- Institute of Agricultural and Nutritional Sciences; Martin Luther University Halle-Wittenberg; Halle/Saale Germany
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19
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Chistiakov DA, Bobryshev YV, Orekhov AN. Macrophage-mediated cholesterol handling in atherosclerosis. J Cell Mol Med 2015; 20:17-28. [PMID: 26493158 PMCID: PMC4717859 DOI: 10.1111/jcmm.12689] [Citation(s) in RCA: 330] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 08/19/2015] [Indexed: 02/06/2023] Open
Abstract
Formation of foam cells is a hallmark at the initial stages of atherosclerosis. Monocytes attracted by pro-inflammatory stimuli attach to the inflamed vascular endothelium and penetrate to the arterial intima where they differentiate to macrophages. Intimal macrophages phagocytize oxidized low-density lipoproteins (oxLDL). Several scavenger receptors (SR), including CD36, SR-A1 and lectin-like oxLDL receptor-1 (LOX-1), mediate oxLDL uptake. In late endosomes/lysosomes of macrophages, oxLDL are catabolysed. Lysosomal acid lipase (LAL) hydrolyses cholesterol esters that are enriched in LDL to free cholesterol and free fatty acids. In the endoplasmic reticulum (ER), acyl coenzyme A: cholesterol acyltransferase-1 (ACAT1) in turn catalyses esterification of cholesterol to store cholesterol esters as lipid droplets in the ER of macrophages. Neutral cholesteryl ester hydrolases nCEH and NCEH1 are involved in a secondary hydrolysis of cholesterol esters to liberate free cholesterol that could be then out-flowed from macrophages by cholesterol ATP-binding cassette (ABC) transporters ABCA1 and ABCG1 and SR-BI. In atherosclerosis, disruption of lipid homoeostasis in macrophages leads to cholesterol accumulation and formation of foam cells.
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Affiliation(s)
- Dimitry A Chistiakov
- Division of Laboratory Medicine, Department of Molecular Genetic Diagnostics and Cell Biology, Institute of Pediatrics, Research Center for Children's Health, Moscow, Russia
| | - Yuri V Bobryshev
- Faculty of Medicine and St Vincent's Centre for Applied Medical Research, University of New South Wales, Sydney, NSW, Australia.,School of Medicine, University of Western Sydney, Campbelltown, NSW, Australia.,Institute for Atherosclerosis Research, Skolkovo Innovative Center, Moscow, Russia
| | - Alexander N Orekhov
- Institute for Atherosclerosis Research, Skolkovo Innovative Center, Moscow, Russia.,Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Sciences, Moscow, Russia.,Department of Biophysics, Biological Faculty, Moscow State University, Moscow, Russia
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20
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Fink IR, Benard EL, Hermsen T, Meijer AH, Forlenza M, Wiegertjes GF. Molecular and functional characterization of the scavenger receptor CD36 in zebrafish and common carp. Mol Immunol 2015; 63:381-93. [DOI: 10.1016/j.molimm.2014.09.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 09/11/2014] [Accepted: 09/17/2014] [Indexed: 11/26/2022]
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21
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Anderson CM, Kazantzis M, Wang J, Venkatraman S, Goncalves RLS, Quinlan CL, Ng R, Jastroch M, Benjamin DI, Nie B, Herber C, Van AAN, Park MJ, Yun D, Chan K, Yu A, Vuong P, Febbraio M, Nomura DK, Napoli JL, Brand MD, Stahl A. Dependence of brown adipose tissue function on CD36-mediated coenzyme Q uptake. Cell Rep 2015; 10:505-15. [PMID: 25620701 DOI: 10.1016/j.celrep.2014.12.048] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 11/13/2014] [Accepted: 12/19/2014] [Indexed: 02/05/2023] Open
Abstract
Brown adipose tissue (BAT) possesses the inherent ability to dissipate metabolic energy as heat through uncoupled mitochondrial respiration. An essential component of the mitochondrial electron transport chain is coenzyme Q (CoQ). While cells synthesize CoQ mostly endogenously, exogenous supplementation with CoQ has been successful as a therapy for patients with CoQ deficiency. However, which tissues depend on exogenous CoQ uptake as well as the mechanism by which CoQ is taken up by cells and the role of this process in BAT function are not well understood. Here, we report that the scavenger receptor CD36 drives the uptake of CoQ by BAT and is required for normal BAT function. BAT from mice lacking CD36 displays CoQ deficiency, impaired CoQ uptake, hypertrophy, altered lipid metabolism, mitochondrial dysfunction, and defective nonshivering thermogenesis. Together, these data reveal an important new role for the systemic transport of CoQ to BAT and its function in thermogenesis.
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Affiliation(s)
- Courtney M Anderson
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA
| | - Melissa Kazantzis
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA
| | - Jinshan Wang
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA
| | - Subramaniam Venkatraman
- Department of Electrical Engineering and Computer Sciences, University of California Berkeley, Berkeley, CA 94720, USA
| | | | - Casey L Quinlan
- The Buck Institute for Research on Aging, Novato, CA 94945, USA
| | - Ryan Ng
- The Buck Institute for Research on Aging, Novato, CA 94945, USA
| | - Martin Jastroch
- The Buck Institute for Research on Aging, Novato, CA 94945, USA
| | - Daniel I Benjamin
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA
| | - Biao Nie
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA
| | - Candice Herber
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA
| | - An-Angela Ngoc Van
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA
| | - Michael J Park
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA
| | - Dawee Yun
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA
| | - Karen Chan
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA
| | - Angela Yu
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA
| | - Peter Vuong
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA
| | - Maria Febbraio
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Daniel K Nomura
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA
| | - Joseph L Napoli
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA
| | - Martin D Brand
- The Buck Institute for Research on Aging, Novato, CA 94945, USA
| | - Andreas Stahl
- Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, USA.
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22
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Kartz GA, Holme RL, Nicholson K, Sahoo D. SR-BI/CD36 chimeric receptors define extracellular subdomains of SR-BI critical for cholesterol transport. Biochemistry 2014; 53:6173-82. [PMID: 25211142 PMCID: PMC4188264 DOI: 10.1021/bi500706x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
High-density lipoproteins (HDLs) are athero-protective, primarily because of their ability to promote cholesterol flux from peripheral tissues to the liver by reverse cholesterol transport (RCT). The delivery of HDL-cholesteryl esters (CE) into cells is mediated by the HDL receptor, scavenger receptor class B type I (SR-BI), a promising target for enhancing whole body cholesterol disposal and preventing cardiovascular disease. A detailed understanding of the structural determinants underlying proper SR-BI/HDL alignment that supports the selective uptake of HDL-CE into cells remains lacking. To this end, we exploited CD36, a class B scavenger receptor with a predicted topology similar to that of SR-BI that binds HDL but is unable to mediate efficient selective uptake of HDL-CE. We generated a series of SR-BI/CD36 chimeric receptors that span the extracellular (EC) domain of SR-BI to delineate regions that are essential for SR-BI's cholesterol transport functions. All 16 SR-BI/CD36 chimeras were transiently expressed in COS-7 cells, and their plasma membrane localization was confirmed. The majority of SR-BI/CD36 chimeric receptors displayed significant reductions in their ability to (i) bind HDL, (ii) deliver HDL-CE to cells, (iii) mediate efflux of free cholesterol (FC) to HDL, and (iv) redistribute plasma membrane domains of FC. We also demonstrated that changes in SR-BI function were independent of receptor oligomerization. Altogether, we have identified discrete subdomains, particularly in the N-terminal and C-terminal regions of the EC domain of SR-BI, that are critical for productive receptor-ligand interactions and the various cholesterol transport functions of SR-BI.
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Affiliation(s)
- Gabriella A Kartz
- Departments of Pharmacology & Toxicology, ‡Biochemistry, and §Medicine, Medical College of Wisconsin , Milwaukee, Wisconsin 53226, United States
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23
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Yamayoshi S, Fujii K, Koike S. Receptors for enterovirus 71. Emerg Microbes Infect 2014; 3:e53. [PMID: 26038749 PMCID: PMC4126179 DOI: 10.1038/emi.2014.49] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 04/05/2014] [Accepted: 05/05/2014] [Indexed: 11/10/2022]
Abstract
Enterovirus 71 (EV71) is one of the major causative agents of hand, foot and mouth disease (HFMD). Occasionally, EV71 infection is associated with severe neurological diseases, such as acute encephalitis, acute flaccid paralysis and cardiopulmonary failure. Several molecules act as cell surface receptors that stimulate EV71 infection, including scavenger receptor B2 (SCARB2), P-selectin glycoprotein ligand-1 (PSGL-1), sialylated glycan, heparan sulfate and annexin II (Anx2). SCARB2 plays critical roles in attachment, viral entry and uncoating, and it can facilitate efficient EV71 infection. The three-dimensional structures of the mature EV71 virion, procapsid and empty capsid, as well as the exofacial domain of SCARB2, have been elucidated. This structural information has greatly increased our understanding of the early steps of EV71 infection. Furthermore, SCARB2 plays essential roles in the development of EV71 neurological disease in vivo. Adult mice are not susceptible to infection by EV71, but transgenic mice that express human SCARB2 become susceptible to EV71 infection and develop similar neurological diseases to those found in humans. This mouse model facilitates the in vivo investigation of many issues related to EV71. PSGL-1, sialylated glycan, heparan sulfate and Anx2 are attachment receptors, which enhance viral infection by retaining the virus on the cell surface. These molecules also contribute to viral infection in vitro either by interacting with SCARB2 or independently of SCARB2. However, the cooperative effects of these receptors, and their contribution to EV71 pathogenicity in vivo, remain to be elucidated.
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Affiliation(s)
- Seiya Yamayoshi
- Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, The University of Tokyo , Tokyo 108-8639, Japan
| | - Ken Fujii
- Neurovirology Project, Tokyo Metropolitan Institute of Medical Science , Tokyo 156-8506, Japan
| | - Satoshi Koike
- Neurovirology Project, Tokyo Metropolitan Institute of Medical Science , Tokyo 156-8506, Japan
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24
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Zhao Y, Ren J, Padilla-Parra S, Fry EE, Stuart DI. Lysosome sorting of β-glucocerebrosidase by LIMP-2 is targeted by the mannose 6-phosphate receptor. Nat Commun 2014; 5:4321. [PMID: 25027712 PMCID: PMC4104448 DOI: 10.1038/ncomms5321] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 06/05/2014] [Indexed: 01/25/2023] Open
Abstract
The integral membrane protein LIMP-2 has been a paradigm for mannose 6-phosphate receptor (MPR) independent lysosomal targeting, binding to β-glucocerebrosidase (β-GCase) and directing it to the lysosome, before dissociating in the late-endosomal/lysosomal compartments. Here we report structural results illuminating how LIMP-2 binds and releases β-GCase according to changes in pH, via a histidine trigger, and suggesting that LIMP-2 localizes the ceramide portion of the substrate adjacent to the β-GCase catalytic site. Remarkably, we find that LIMP-2 bears P-Man9GlcNAc2 covalently attached to residue N325, and that it binds MPR, via mannose 6-phosphate, with a similar affinity to that observed between LIMP-2 and β-GCase. The binding sites for β-GCase and the MPR are functionally separate, so that a stable ternary complex can be formed. By fluorescence lifetime imaging microscopy, we also demonstrate that LIMP-2 interacts with MPR in living cells. These results revise the accepted view of LIMP-2-β-GCase lysosomal targeting.
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Affiliation(s)
- Yuguang Zhao
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK
- These authors contributed equally to this work
| | - Jingshan Ren
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK
- These authors contributed equally to this work
| | - Sergi Padilla-Parra
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK
| | - Elizabeth E. Fry
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK
| | - David I. Stuart
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK
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Park YM. CD36, a scavenger receptor implicated in atherosclerosis. Exp Mol Med 2014; 46:e99. [PMID: 24903227 PMCID: PMC4081553 DOI: 10.1038/emm.2014.38] [Citation(s) in RCA: 351] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 03/17/2014] [Accepted: 04/08/2014] [Indexed: 12/17/2022] Open
Abstract
CD36 is a membrane glycoprotein that is present on various types of cells, including monocytes, macrophages, microvascular endothelial cells, adipocytes and platelets. Macrophage CD36 participates in atherosclerotic arterial lesion formation through its interaction with oxidized low-density lipoprotein (oxLDL), which triggers signaling cascades for inflammatory responses. CD36 functions in oxLDL uptake and foam cell formation, which is the initial critical stage of atherosclerosis. In addition, oxLDL via CD36 inhibits macrophage migration, which may be a macrophage-trapping mechanism in atherosclerotic lesions. The role of CD36 was examined in in vitro studies and in vivo experiments, which investigated various functions of CD36 in atherosclerosis and revealed that CD36 deficiency reduces atherosclerotic lesion formation. Platelet CD36 also promotes atherosclerotic inflammatory processes and is involved in thrombus formation after atherosclerotic plaque rupture. Because CD36 is an essential component of atherosclerosis, defining the function of CD36 and its corresponding signaling pathway may lead to a new treatment strategy for atherosclerosis.
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Affiliation(s)
- Young Mi Park
- Department of Molecular Medicine, Ewha Womans University School of Medicine, Seoul, Republic of Korea
- Ewha Global Top 5 Research Program, Ewha Womans University, Seoul, Republic of Korea
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26
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Coutinho MF, Prata MJ, Alves S. A shortcut to the lysosome: the mannose-6-phosphate-independent pathway. Mol Genet Metab 2012; 107:257-66. [PMID: 22884962 DOI: 10.1016/j.ymgme.2012.07.012] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 07/12/2012] [Indexed: 12/12/2022]
Abstract
Lysosomal hydrolases have long been known to be responsible for the degradation of different substrates in the cell. These acid hydrolases are synthesized in the rough endoplasmic reticulum and transported through the Golgi apparatus to the trans-Golgi network (TGN). From there, they are delivered to endosomal/lysosomal compartments, where they finally become active due to the acidic pH characteristic of the lysosomal compartment. The majority of the enzymes leave the TGN after modification with mannose-6-phosphate (M6P) residues, which are specifically recognized by M6P receptors (MPRs), ensuring their transport to the endosomal/lysosomal system. Although M6P receptors play a major role in the intracellular transport of newly synthesized lysosomal enzymes in mammalian cells, several lines of evidence suggest the existence of alternative processes of lysosomal targeting. Among them, the two that are mediated by the M6P alternative receptors, lysosomal integral membrane protein (LIMP-2) and sortilin, have gained unequivocal support. LIMP-2 was shown to be implicated in the delivery of beta-glucocerebrosidase (GCase) to the lysosomes, whereas sortilin has been suggested to be a multifunctional receptor capable of binding several different ligands, including neurotensin and receptor-associated protein (RAP), and of targeting several proteins to the lysosome, including sphingolipid activator proteins (prosaposin and GM2 activator protein), acid sphingomyelinase and cathepsins D and H. Here, we review the current knowledge on these two proteins: their discovery, study, structural features and cellular function, with special attention to their role as alternative receptors to lysosomal trafficking. Recent studies associating both LIMP2 and sortilin to disease are also extensively reviewed.
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27
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Nishimura Y, Shimizu H. Cellular receptors for human enterovirus species a. Front Microbiol 2012; 3:105. [PMID: 22470371 PMCID: PMC3313065 DOI: 10.3389/fmicb.2012.00105] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 03/02/2012] [Indexed: 12/22/2022] Open
Abstract
Human enterovirus species A (HEV-A) is one of the four species of HEV in the genus Enterovirus in the family Picornaviridae. Among HEV-A, coxsackievirus A16 (CVA16) and enterovirus 71 (EV71) are the major causative agents of hand, foot, and mouth disease (HFMD). Some other types of HEV-A are commonly associated with herpangina. Although HFMD and herpangina due to HEV-A are common febrile diseases among infants and children, EV71 can cause various neurological diseases, such as aseptic meningitis and fatal encephalitis. Recently, two human transmembrane proteins, P-selectin glycoprotein ligand-1 (PSGL-1) and scavenger receptor class B, member 2 (SCARB2), were identified as functional receptors for EV71 and CVA16. In in vitro infection experiments using the prototype HEV-A strains, PSGL-1 and SCARB2 could be responsible for the specific receptors for EV71 and CVA16. However, the involvement of both receptors in the in vitro and in vivo infections of clinical isolates of HEV-A has not been clarified yet. To elucidate a diverse array of the clinical outcome of HEV-A-associated diseases, the identification and characterization of HEV-A receptors may provide useful information in understanding the HEV-A pathogenesis at a molecular level.
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Affiliation(s)
- Yorihiro Nishimura
- Department of Virology II, National Institute of Infectious Diseases Musashimurayama-shi, Tokyo, Japan
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28
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Michelakakis H, Xiromerisiou G, Dardiotis E, Bozi M, Vassilatis D, Kountra PM, Patramani G, Moraitou M, Papadimitriou D, Stamboulis E, Stefanis L, Zintzaras E, Hadjigeorgiou GM. Evidence of an association between the scavenger receptor class B member 2 gene and Parkinson's disease. Mov Disord 2012; 27:400-5. [PMID: 22223122 DOI: 10.1002/mds.24886] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2010] [Revised: 11/21/2011] [Accepted: 11/23/2011] [Indexed: 12/21/2022] Open
Abstract
Lysosomal protein 2 (LIMP2), the product of the scavenger receptor class B member 2 (SCARB2) gene, is a ubiquitously expressed transmembrane protein that is the mannose-6-phosphate-independent receptor for glucocerebrosidase (β-GCase); a deficiency in this protein causes Gaucher disease. Several studies have shown a link between mutations in the β-GCase gene and diseases characterized clinically by Parkinsonism and by the presence of Lewy body-related pathology. We hypothesized that genetic variants in the SCARB2 gene could be risk factors for Parkinson's disease (PD). A candidate-gene study of 347 Greek patients with sporadic PD and 329 healthy controls was conducted to investigate the association between 5 polymorphisms in the SCARB2 gene (rs6824953, rs6825004, rs4241591, rs9991821, and rs17234715) and the development of PD. The single-locus analysis for the 5 polymorphisms revealed an association only for the rs6825004 polymorphism: the generalized odds ratio (OR(G) ) was 0.68 (95% confidence interval [CI], 0.51-0.90), and the OR for the allelic test was OR = 0.71 (95% CI, 0.56-0.90). Haplotype analysis showed an association for the GCGGT haplotype (P < .01). Our study supports a genetic contribution of the SCARB2 locus to PD; future studies in larger cohorts are necessary to verify this finding.
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Affiliation(s)
- Helen Michelakakis
- Department of Enzymology and Cellular Function, Institute of Child Health, Aghia Sophidara Children's Hospital, Athens, Greece
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29
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Yamayoshi S, Fujii K, Koike S. Scavenger receptor b2 as a receptor for hand, foot, and mouth disease and severe neurological diseases. Front Microbiol 2012; 3:32. [PMID: 22363322 PMCID: PMC3277273 DOI: 10.3389/fmicb.2012.00032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 01/18/2012] [Indexed: 01/12/2023] Open
Abstract
Enterovirus 71 (EV71) is one of the major causative agents of hand, foot, and mouth disease (HFMD). Infection with EV71 is occasionally associated with severe neurological diseases such as acute encephalitis, acute flaccid paralysis, and cardiopulmonary failure. Because cellular receptors for viruses play an important role in cell, tissue, and species tropism, it is important to identify and characterize the receptor molecule. Recently, cellular receptors and host factors that stimulate EV71 infection have been identified. Several lines of evidence suggest that scavenger receptor class B, member 2 (SCARB2) plays critical roles in efficient EV71 infection and the development of disease in humans. In this review, we will summarize the findings of recent studies on EV71 infection and on the roles of SCARB2.
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Affiliation(s)
- Seiya Yamayoshi
- Neurovirology Project, Tokyo Metropolitan Institute of Medical Science Tokyo, Japan
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30
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Abstract
Toll-like receptors (TLRs) are essential components of the innate immune system. Accessory proteins are required for the biosynthesis and activation of TLRs. Here, we summarize recent findings on TLR accessory proteins that are required for cell-surface and endosomal TLR function, and we classify these proteins based on their function as ligand-recognition and delivery cofactors, chaperones and trafficking proteins. Because of their essential roles in TLR function, targeting of such accessory proteins may benefit strategies aimed at manipulating TLR activation for therapeutic applications.
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31
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Gigante M, Piemontese M, Gesualdo L, Iolascon A, Aucella F. Molecular and genetic basis of inherited nephrotic syndrome. Int J Nephrol 2011; 2011:792195. [PMID: 21904677 PMCID: PMC3167185 DOI: 10.4061/2011/792195] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 06/16/2011] [Accepted: 06/16/2011] [Indexed: 12/26/2022] Open
Abstract
Nephrotic syndrome is an heterogeneous disease characterized by increased permeability of the glomerular filtration barrier for macromolecules. Podocytes, the visceral epithelial cells of glomerulus, play critical role in ultrafiltration of plasma and are involved in a wide number of inherited and acquired glomerular diseases. The identification of mutations in nephrin and other podocyte genes as causes of genetic forms of nephrotic syndrome has revealed new important aspects of the pathogenesis of proteinuric kidney diseases and expanded our knowledge of the glomerular biology. Moreover, a novel concept of a highly dynamic slit diaphragm proteins is emerging. The most significant discoveries in our understanding of the structure and function of the glomerular filtration barrier are reviewed in this paper.
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Affiliation(s)
- Maddalena Gigante
- Division of Nephrology, Department of Biomedical Science, University of Foggia, 71121 Foggia, Italy
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32
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Yang Y, Wang L, Si S, Hong B. How can high-throughput screening deliver drugs to treat atherosclerosis? Expert Opin Drug Discov 2010; 5:1175-88. [DOI: 10.1517/17460441.2010.529896] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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33
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Stephen SL, Freestone K, Dunn S, Twigg MW, Homer-Vanniasinkam S, Walker JH, Wheatcroft SB, Ponnambalam S. Scavenger receptors and their potential as therapeutic targets in the treatment of cardiovascular disease. Int J Hypertens 2010; 2010:646929. [PMID: 20981357 PMCID: PMC2958427 DOI: 10.4061/2010/646929] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 07/07/2010] [Indexed: 12/12/2022] Open
Abstract
Scavenger receptors act as membrane-bound and soluble proteins that bind to macromolecular complexes and pathogens. This diverse supergroup of proteins mediates binding to modified lipoprotein particles which regulate the initiation and progression of atherosclerotic plaques. In vascular tissues, scavenger receptors are implicated in regulating intracellular signaling, lipid accumulation, foam cell development, and cellular apoptosis or necrosis linked to the pathophysiology of atherosclerosis. One approach is using gene therapy to modulate scavenger receptor function in atherosclerosis. Ectopic expression of membrane-bound scavenger receptors using viral vectors can modify lipid profiles and reduce the incidence of atherosclerosis. Alternatively, expression of soluble scavenger receptors can also block plaque initiation and progression. Inhibition of scavenger receptor expression using a combined gene therapy and RNA interference strategy also holds promise for long-term therapy. Here we review our current understanding of the gene delivery by viral vectors to cells and tissues in gene therapy strategies and its application to the modulation of scavenger receptor function in atherosclerosis.
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Affiliation(s)
- Sam L Stephen
- Endothelial Cell Biology Unit, Institute of Molecular & Cellular Biology, LIGHT Laboratories, University of Leeds, Clarendon Way, Leeds LS2 9JT, UK
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Mavridou S, Venihaki M, Rassouli O, Tsatsanis C, Kardassis D. Feedback inhibition of human scavenger receptor class B type I gene expression by glucocorticoid in adrenal and ovarian cells. Endocrinology 2010; 151:3214-24. [PMID: 20463057 DOI: 10.1210/en.2009-1302] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Scavenger receptor class B type I (SR-BI) facilitates the reverse transport of excess cholesterol from peripheral tissues to the liver via high-density lipoproteins. In steroidogenic tissues, SR-BI supplies cholesterol for steroid hormone production. We show here that the transcription of the human SR-BI gene is subject to feedback inhibition by glucocorticoid in adrenal and ovarian cells. SR-BI mRNA levels were increased in adrenals from corticosterone-insufficient Crh(-/-) mice, whereas corticosterone replacement by oral administration inhibited SR-BI gene expression in these mice. SR-BI mRNA levels were increased in adrenals from wild-type mice treated with metyrapone, a drug that blocks corticosterone synthesis. Experiments in adrenocortical H295R and ovarian SKOV-3 cells using cycloheximide and siRNA-mediated gene silencing revealed that glucocorticoid-mediated inhibition of SR-BI gene transcription requires de novo protein synthesis and the glucocorticoid receptor (GR). No direct binding of GR to the SR-BI promoter could be demonstrated in vitro and in vivo, suggesting an indirect mechanism of repression of SR-BI gene transcription by GR in adrenal cells. Deletion analysis established that the region of the human SR-BI promoter between nucleotides -201 and -62 is sufficient to mediate repression by glucocorticoid. This region contains putative binding sites for transcriptional repressors that could play a role in SR-BI gene regulation in response to glucocorticoid. In summary, this is the first report showing that glucocorticoid suppress SR-BI expression suggesting that steroidogenic tissues maintain steroid hormone homeostasis by prohibiting SR-BI-mediated high-density lipoprotein cholesterol uptake when the endogenous levels of glucocorticoid are elevated.
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Affiliation(s)
- Sofia Mavridou
- Department of Basic Sciences, Foundation of Research and Technology-Hellas, Heraklion 71003, Greece
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35
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Fujimoto VY, Kane JP, Ishida BY, Bloom MS, Browne RW. High-density lipoprotein metabolism and the human embryo. Hum Reprod Update 2010; 16:20-38. [PMID: 19700490 DOI: 10.1093/humupd/dmp029] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND High-density lipoprotein (HDL) appears to be the dominant lipoprotein particle in human follicular fluid (FF). The reported anti-atherogenic properties of HDL have been attributed in part to reverse cholesterol transport. The discoveries of the scavenger receptor class B type I (SR-BI) and the ATP-binding cassette A1 lipid (ABCA1) transporter have generated studies aimed at unraveling the pathways of HDL biogenesis, remodeling and catabolism. The production of SR-BI and ABCA1 knockout mice as well as other lipoprotein metabolism-associated mutants has resulted in reduced or absent fertility, leading us to postulate the existence of a human hepatic-ovarian HDL-associated axis of fertility. Here, we review an evolving literature on the role of HDL metabolism on mammalian fertility and oocyte development. METHODS An extensive online search was conducted of published articles relevant to the section topics discussed. All relevant English language articles contained in Pubmed/Medline, with no specific time frame for publication, were considered for this narrative review. Cardiovascular literature was highly cited due to the wealth of relevant knowledge on HDL metabolism, and the dearth thereof in the reproductive field. RESULTS Various vertebrate models demonstrate a role for HDL in embryo development and fertility. In our clinical studies, FF levels of HDL cholesterol and apolipoprotein AI levels were negatively associated with embryo fragmentation, but not with embryo cell cleavage rate. However, the HDL component, paraoxonase 1 arylesterase activity, was positively associated with embryo cell cleavage rate. CONCLUSIONS HDL contributes to intra-follicular cholesterol homeostasis which appears to be important for successful oocyte and embryo development.
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Affiliation(s)
- Victor Y Fujimoto
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of California at San Francisco, San Francisco, CA 94115-0916, USA.
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36
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Blanz J, Groth J, Zachos C, Wehling C, Saftig P, Schwake M. Disease-causing mutations within the lysosomal integral membrane protein type 2 (LIMP-2) reveal the nature of binding to its ligand beta-glucocerebrosidase. Hum Mol Genet 2010; 19:563-72. [PMID: 19933215 DOI: 10.1093/hmg/ddp523] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
Action myoclonus-renal failure syndrome (AMRF) is caused by mutations in the lysosomal integral membrane protein type 2 (LIMP-2/SCARB2). LIMP-2 was identified as a sorting receptor for beta-glucocerebrosidase (beta-GC), which is defective in Gaucher disease. To date, six AMRF-causing mutations have been described, including splice site, missense and nonsense mutations. All mutations investigated in this study lead to a retention of LIMP-2 in the endoplasmic reticulum (ER) but affect the binding to beta-GC differentially. From the three nonsense mutations, only the Q288X mutation was still able to bind to beta-GC as efficiently as compared with wild-type LIMP-2, whereas the W146SfsX16 and W178X mutations lost their beta-GC-binding capacity almost completely. The LIMP-2 segment 145-288, comprising the nonsense mutations, contains a highly conserved coiled-coil domain, which we suggest determines beta-GC binding. In fact, disruption of the helical arrangement and amphiphatic nature of the coiled-coil domain abolishes beta-GC binding, and a synthetic peptide comprising the coiled-coil domain of LIMP-2 displays pH-selective multimerization properties. In contrast to the reduced binding properties of the nonsense mutations, the only missense mutation (H363N) found in AMRF leads to increased binding of beta-GC to LIMP-2, indicating that this highly conserved histidine modifies the affinity of LIMP-2 to its ligand. With the present study, we demonstrate that disruption of the coiled-coil structure or AMRF disease-causing mutations abolish beta-GC binding, indicating the importance of an intact coiled-coil structure for the interaction of LIMP-2 and beta-GC.
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Affiliation(s)
- Judith Blanz
- Institut für Biochemie, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany
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Silverstein RL. Type 2 scavenger receptor CD36 in platelet activation: the role of hyperlipemia and oxidative stress. CLINICAL LIPIDOLOGY 2009; 4:767. [PMID: 20161667 PMCID: PMC2819200 DOI: 10.2217/clp.09.57] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Platelet hyper-reactivity and a systemic prothrombotic state are associated with atherosclerosis and other inflammatory conditions. CD36, a member of the Type 2 scavenger receptor family, is a multiligand pattern recognition receptor that recognizes specific oxidized phospholipids, molecules expressed on microbial pathogens, apoptotic cells, and cell-derived microparticles. Recent studies have demonstrated that CD36 binding to oxidized LDL or microparticles activates a specific signaling pathway that induces platelet activation. This pathway is activated in vivo in the setting of hyperlipidemia and oxidant stress. Genetic deletion of CD36 protects mice from pathological thrombosis associated with hyperlipidemia without any apparent effect on normal hemostasis. Targeting CD36 or its signaling pathway could potentially lead to the development of novel antithrombotic therapies for patients with atheroinflammatory disorders.
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Affiliation(s)
- Roy L Silverstein
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic Foundation, Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, 9500 Euclid Ave 44195, NC10, Cleveland, OH, USA Tel.: +1 216 444 5220 Fax: +1 216 444 9404
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Yamayoshi S, Yamashita Y, Li J, Hanagata N, Minowa T, Takemura T, Koike S. Scavenger receptor B2 is a cellular receptor for enterovirus 71. Nat Med 2009; 15:798-801. [PMID: 19543282 DOI: 10.1038/nm.1992] [Citation(s) in RCA: 399] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Accepted: 05/26/2009] [Indexed: 12/17/2022]
Abstract
Enterovirus 71 (EV71) belongs to human enterovirus species A of the genus Enterovirus within the family Picornaviridae. EV71, together with coxsackievirus A16 (CVA16), are most frequently associated with hand, foot and mouth disease (HFMD). Although HFMD is considered a mild exanthematous infection, infections involving EV71, but not CVA16, can progress to severe neurological disease, including fatal encephalitis, aseptic meningitis and acute flaccid paralysis. In recent years, epidemic and sporadic outbreaks of neurovirulent EV71 infections have been reported in Taiwan, Malaysia, Singapore, Japan and China. Here, we show that human scavenger receptor class B, member 2 (SCARB2, also known as lysosomal integral membrane protein II or CD36b like-2) is a receptor for EV71. EV71 binds soluble SCARB2 or cells expressing SCARB2, and the binding is inhibited by an antibody to SCARB2. Expression of human SCARB2 enables normally unsusceptible cell lines to support EV71 propagation and develop cytopathic effects. EV71 infection is hampered by the antibody to SCARB2 and soluble SCARB2. SCARB2 also supports the infection of the milder pathogen CVA16. The identification of SCARB2 as an EV71 and CVA16 receptor contributes to a better understanding of the pathogenicity of these viruses.
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Affiliation(s)
- Seiya Yamayoshi
- Department of Microbiology and Immunology, Tokyo Metropolitan Institute for Neuroscience, Tokyo Metropolitan Organization for Medical Research, Tokyo, Japan
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40
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Silverstein RL, Febbraio M. CD36, a scavenger receptor involved in immunity, metabolism, angiogenesis, and behavior. Sci Signal 2009; 2:re3. [PMID: 19471024 DOI: 10.1126/scisignal.272re3] [Citation(s) in RCA: 797] [Impact Index Per Article: 53.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
CD36 is a membrane glycoprotein present on platelets, mononuclear phagocytes, adipocytes, hepatocytes, myocytes, and some epithelia. On microvascular endothelial cells, CD36 is a receptor for thrombospondin-1 and related proteins and functions as a negative regulator of angiogenesis. On phagocytes, through its functions as a scavenger receptor recognizing specific oxidized phospholipids and lipoproteins, CD36 participates in internalization of apoptotic cells, certain bacterial and fungal pathogens, and modified low-density lipoproteins, thus contributing to inflammatory responses and atherothrombotic diseases. CD36 also binds long-chain fatty acids and facilitates their transport into cells, thus participating in muscle lipid utilization, adipose energy storage, and gut fat absorption and possibly contributing to the pathogenesis of metabolic disorders, such as diabetes and obesity. On sensory cells, CD36 is involved in insect pheromone signaling and rodent fatty food preference. The signaling pathways downstream of CD36 involve ligand-dependent recruitment and activation of nonreceptor tyrosine kinases, specific mitogen-activated protein kinases, and the Vav family of guanine nucleotide exchange factors; modulation of focal adhesion constituents; and generation of intracellular reactive oxygen species. CD36 in many cells is localized in specialized cholesterol-rich membrane microdomains and may also interact with other membrane receptors, such as tetraspanins and integrins. Identification of the precise CD36 signaling pathways in specific cells elicited in response to specific ligands may yield novel targets for drug development.
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Affiliation(s)
- Roy L Silverstein
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA.
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41
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Yang Y, Jiang W, Wang L, Zhang ZB, Si SY, Hong B. Characterization of the Isoflavone Pratensein as a Novel Transcriptional Up-Regulator of Scavenger Receptor Class B Type I in HepG2 Cells. Biol Pharm Bull 2009; 32:1289-94. [DOI: 10.1248/bpb.32.1289] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Yuan Yang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College
| | - Wei Jiang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College
| | - Li Wang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College
| | - Zhong-Bing Zhang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College
| | - Shu-Yi Si
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College
| | - Bin Hong
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College
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Mosig S, Rennert K, Büttner P, Krause S, Lütjohann D, Soufi M, Heller R, Funke H. Monocytes of patients with familial hypercholesterolemia show alterations in cholesterol metabolism. BMC Med Genomics 2008; 1:60. [PMID: 19040724 PMCID: PMC2633353 DOI: 10.1186/1755-8794-1-60] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Accepted: 11/28/2008] [Indexed: 11/12/2022] Open
Abstract
Background Elevated plasma cholesterol promotes the formation of atherosclerotic lesions in which monocyte-derived lipid-laden macrophages are frequently found. To analyze, if circulating monocytes already show increased lipid content and differences in lipoprotein metabolism, we compared monocytes from patients with Familial Hypercholesterolemia (FH) with those from healthy individuals. Methods Cholesterol and oxidized cholesterol metabolite serum levels of FH and of healthy, gender/age matched control subjects were measured by combined gas chromatography – mass spectroscopy. Monocytes from patients with FH and from healthy subjects were isolated by antibody-assisted density centrifugation. Gene expression profiles of isolated monocytes were measured using Affymetrix HG-U 133 Plus 2.0 microarrays. We compared monocyte gene expression profiles from FH patients with healthy controls using a Welch T-test with correction for multiple testing (p < 0.05; Benjamini Hochberg correction, False Discovery Rate = 0.05). The differential expression of FH associated genes was validated at the mRNA level by qRT-PCR and/or at the protein level by Western Blot or flow cytometry. Functional validation of monocyte scavenger receptor activities were done by binding assays and dose/time dependent uptake analysis using native and oxidized LDL. Results Using microarray analysis we found in FH patients a significant up-regulation of 1,617 genes and a down-regulation of 701 genes compared to monocytes from healthy individuals. These include genes of proteins that are involved in the uptake, biosynthesis, disposition, and cellular efflux of cholesterol. In addition, plasma from FH patients contains elevated amounts of sterols and oxysterols. An increased uptake of oxidized as well as of native LDL by FH monocytes combined with a down-regulation of NPC1 and ABCA1 explains the lipid accumulation observed in these cells. Conclusion Our data demonstrate that circulating FH monocytes show differences in cell physiology that may contribute to the early onset of atherosclerosis in this disease.
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Affiliation(s)
- Sandy Mosig
- Molecular Hemostaseology, Friedrich-Schiller-University of Jena, Bachstrasse 18, 07743 Jena, Germany.
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43
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Akashi-Takamura S, Miyake K. TLR accessory molecules. Curr Opin Immunol 2008; 20:420-5. [PMID: 18625310 DOI: 10.1016/j.coi.2008.07.001] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 07/02/2008] [Accepted: 07/02/2008] [Indexed: 10/21/2022]
Abstract
Accessory molecules are required for microbial recognition by Toll-like receptor (TLR), subsequent signaling, and regulation of ensuing immune responses. Accessory molecules regulate TLRs on the cell surface (MD-2 and RP105), or in the endoplasmic reticulum (ER) (Unc93B, PRAT4A, and gp96). Other types of accessory molecules modulate TLR responses by acting directly on TLR ligands (CD14, CD36, HMGB1, and the antimicrobial peptide LL37). These molecules cooperate with TLR, inducing appropriate defense mechanisms. It is important to understand how TLR signaling is controlled by these accessory molecules. These accessory molecules could be promising targets for therapeutic intervention in infectious disease and immune disorders.
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Affiliation(s)
- Sachiko Akashi-Takamura
- Division of Infectious Genetics, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, Japan
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Balreira A, Gaspar P, Caiola D, Chaves J, Beirão I, Lima JL, Azevedo JE, Miranda MCS. A nonsense mutation in the LIMP-2 gene associated with progressive myoclonic epilepsy and nephrotic syndrome. Hum Mol Genet 2008; 17:2238-43. [PMID: 18424452 DOI: 10.1093/hmg/ddn124] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The main clinical features of two siblings from a consanguineous marriage were progressive myoclonic epilepsy without intellectual impairment and a nephrotic syndrome with a strong accumulation of C1q in capillary loops and mesangium of kidney. The biochemical analysis of one of the patients revealed a normal beta-glucocerebrosidase activity in leukocytes, but a severe enzymatic deficiency in cultured skin fibroblasts. This deficiency suggested a defect in the intracellular sorting pathway of this enzyme. The sequence analysis of the gene encoding LIMP-2 (SCARB2), the sorting receptor for beta-glucocerebrosidase, confirmed this hypothesis. A homozygous nonsense mutation in codon 178 of SCARB2 was found in the patient, whereas her healthy parents were heterozygous for the mutation. Besides lacking immunodetectable LIMP-2, patient fibroblasts also had decreased amounts of beta-glucocerebrosidase, which was mainly located in the endoplasmic reticulum, as assessed by its sensitivity to Endo H. This is the first report of a mutation in the SCARB2 gene associated with a human disease, which, contrary to earlier proposals, shares no features with Charcot-Marie-Tooth disease both at the clinical and neurophysiological levels.
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Affiliation(s)
- Andrea Balreira
- Unidade de Biologia do Lisossoma e do Peroxissoma, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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Zhang J, Chu W, Crandall I. Lipoprotein binding preference of CD36 is altered by filipin treatment. Lipids Health Dis 2008; 7:23. [PMID: 18582374 PMCID: PMC2483703 DOI: 10.1186/1476-511x-7-23] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Accepted: 06/26/2008] [Indexed: 11/30/2022] Open
Abstract
The class B scavenger receptor CD36 binds multiple ligands, including oxidized and native lipoprotein species. CD36 and the related receptor SR-B1 have been localized to caveolae, domains that participate in cell signaling, transcytosis, and regulation of cellular cholesterol homeostasis. Previous work has indicated that the ligand preference of CD36 may depend on the cell type in which it is expressed. To determine if the presence or absence of caveolae is the determining factor for lipoprotein preference, we treated CHO-CD36 and C32 cells with filipin. Filipin treatment rapidly increased the binding capacity of CD36 for the native lipoproteins HDL and LDL, but did not affect the binding capacity of CD36 for oxidized LDL. Filipin treatment affected the distribution of caveolin and CD36 suggesting that the presence caveolae may modulate the ligand preference of CD36. However, its molecular mechanism how CD36 and caveolin interaction in regulating lipoprotein transport remains to be further studied.
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Affiliation(s)
- Jianshe Zhang
- Department of Bioengineering and Environmental Science, Changsha University, Changsha, Hunan, PR China.
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46
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Vidal SM, Malo D, Marquis JF, Gros P. Forward genetic dissection of immunity to infection in the mouse. Annu Rev Immunol 2008; 26:81-132. [PMID: 17953509 DOI: 10.1146/annurev.immunol.26.021607.090304] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Forward genetics is an experimental approach in which gene mapping and positional cloning are used to elucidate the molecular mechanisms underlying phenotypic differences between two individuals for a given trait. This strategy has been highly successful for the study of inbred mouse strains that show differences in innate susceptibility to bacterial, parasitic, fungal, and viral infections. Over the past 20 years, these studies have led to the identification of a number of cell populations and critical biochemical pathways and proteins that are essential for the early detection of and response to invading pathogens. Strikingly, the macrophage is the point of convergence for many of these genetic studies. This has led to the identification of diverse pathways involved in extracellular and intracellular pathogen recognition, modification of the properties and content of phagosomes, transcriptional response, and signal transduction for activation of adaptive immune mechanisms. In models of viral infections, elegant genetic studies highlighted the pivotal role of natural killer cells in the detection and destruction of infected cells.
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Affiliation(s)
- S M Vidal
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada H3G 1Y6
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Komori H, Arai H, Kashima T, Huby T, Kita T, Ueda Y. Coexpression of CLA-1 and human PDZK1 in murine liver modulates HDL cholesterol metabolism. Arterioscler Thromb Vasc Biol 2008; 28:1298-303. [PMID: 18403724 DOI: 10.1161/atvbaha.108.165845] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE In rodents scavenger receptor class B type I (SR-BI) is a key molecule for selective uptake of cholesteryl ester from high-density lipoprotein (HDL). This study was aimed to clarify the role of the human SR-BI/CD36 and LIMP-II Analogues-1 (CLA-1) as a molecular target of selective uptake of cholesteryl ester from HDL in vivo. METHODS AND RESULTS To clarify the function and regulation of CLA-1 in vivo we produced CLA-1 BAC transgenic mice. In spite of abundant hepatic RNA expression of CLA-1, CLA-1 BAC transgenic mice had no significant effect on mouse HDL cholesterol. Although coexpression of a human scaffolding protein PDZK1 along with CLA-1 enhanced hepatic CLA-1 expression, it did not affect mouse HDL cholesterol levels, either. However, in the presence of human apoA-1, HDL cholesterol level and size were significantly reduced in CLA-1 transgenic mice, and its reduction was more pronounced in CLA-1/human PDZK1 double transgenic mouse. CONCLUSIONS We established a mouse model to study human reverse cholesterol transport by expressing CLA-1, human PDZK1, and human apoA-I gene. Our results imply that enhancing CLA-1 expression by human PDZK1 in the liver can modulate HDL cholesterol metabolism and possibly enhance reverse cholesterol transport to prevent the progression of atherosclerosis in human.
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Affiliation(s)
- Hidenori Komori
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
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Berkovic SF, Dibbens LM, Oshlack A, Silver JD, Katerelos M, Vears DF, Lüllmann-Rauch R, Blanz J, Zhang KW, Stankovich J, Kalnins RM, Dowling JP, Andermann E, Andermann F, Faldini E, D'Hooge R, Vadlamudi L, Macdonell RA, Hodgson BL, Bayly MA, Savige J, Mulley JC, Smyth GK, Power DA, Saftig P, Bahlo M. Array-based gene discovery with three unrelated subjects shows SCARB2/LIMP-2 deficiency causes myoclonus epilepsy and glomerulosclerosis. Am J Hum Genet 2008; 82:673-84. [PMID: 18308289 PMCID: PMC2427287 DOI: 10.1016/j.ajhg.2007.12.019] [Citation(s) in RCA: 175] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 12/10/2007] [Accepted: 12/28/2007] [Indexed: 01/09/2023] Open
Abstract
Action myoclonus-renal failure syndrome (AMRF) is an autosomal-recessive disorder with the remarkable combination of focal glomerulosclerosis, frequently with glomerular collapse, and progressive myoclonus epilepsy associated with storage material in the brain. Here, we employed a novel combination of molecular strategies to find the responsible gene and show its effects in an animal model. Utilizing only three unrelated affected individuals and their relatives, we used homozygosity mapping with single-nucleotide polymorphism chips to localize AMRF. We then used microarray-expression analysis to prioritize candidates prior to sequencing. The disorder was mapped to 4q13-21, and microarray-expression analysis identified SCARB2/Limp2, which encodes a lysosomal-membrane protein, as the likely candidate. Mutations in SCARB2/Limp2 were found in all three families used for mapping and subsequently confirmed in two other unrelated AMRF families. The mutations were associated with lack of SCARB2 protein. Reanalysis of an existing Limp2 knockout mouse showed intracellular inclusions in cerebral and cerebellar cortex, and the kidneys showed subtle glomerular changes. This study highlights that recessive genes can be identified with a very small number of subjects. The ancestral lysosomal-membrane protein SCARB2/LIMP-2 is responsible for AMRF. The heterogeneous pathology in the kidney and brain suggests that SCARB2/Limp2 has pleiotropic effects that may be relevant to understanding the pathogenesis of other forms of glomerulosclerosis or collapse and myoclonic epilepsies.
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Affiliation(s)
- Samuel F Berkovic
- Department of Medicine, Austin Health and Northern Health, Heidelberg, Victoria 3081, Australia.
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Zhang J, Crandall I. Expression of both N- and C-terminal GFP tagged huCD36 and their discrepancy in OxLDL and pRBC binding on CHO cells. Lipids Health Dis 2007; 6:24. [PMID: 17888147 PMCID: PMC2064913 DOI: 10.1186/1476-511x-6-24] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Accepted: 09/21/2007] [Indexed: 01/26/2023] Open
Abstract
CD36, an 88 kDa membrane glycoprotein, is found in several cell types and it has been characterized to have two hydrophobic domains at their N- and C-termini which are essential for protein folding and targeting. In this study, we first tagged the green fluorescent protein (GFP) to both the N- and C-termini of huCD36 and investigated their cellular expression and influences on lipoprotein and plasmodium falciparium parasitized erythrocytes (pRBC) binding. Our work revealed that huCD36 proteins are expressed normally irrespective of the GFP tag presence at either the N- or C-termini. However, the two recombinant proteins showed discrepancy in uptake and surface-binding of OxLDL but they did not affect pRBC binding. These results suggested that the interaction between oxLDL and CD36 could be blocked using recombinant proteins and this may be useful in potential control of the trafficking of modified lipoproteins into monocytes leading to atherogenesis.
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Affiliation(s)
- Jianshe Zhang
- Department of Bioengineering and Environmental Science, Changsha University, Changsha, Hunan, China 41003
| | - Ian Crandall
- Department of Medicine, University of Toronto, Toronto, ON, Canada M5S 1X8
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50
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Beutler B, Jiang Z, Georgel P, Crozat K, Croker B, Rutschmann S, Du X, Hoebe K. Genetic analysis of host resistance: Toll-like receptor signaling and immunity at large. Annu Rev Immunol 2006; 24:353-89. [PMID: 16551253 DOI: 10.1146/annurev.immunol.24.021605.090552] [Citation(s) in RCA: 603] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Classical genetic methods, driven by phenotype rather than hypotheses, generally permit the identification of all proteins that serve nonredundant functions in a defined biological process. Long before this goal is achieved, and sometimes at the very outset, genetics may cut to the heart of a biological puzzle. So it was in the field of mammalian innate immunity. The positional cloning of a spontaneous mutation that caused lipopolysaccharide resistance and susceptibility to Gram-negative infection led directly to the understanding that Toll-like receptors (TLRs) are essential sensors of microbial infection. Other mutations, induced by the random germ line mutagen ENU (N-ethyl-N-nitrosourea), have disclosed key molecules in the TLR signaling pathways and helped us to construct a reasonably sophisticated portrait of the afferent innate immune response. A still broader genetic screen--one that detects all mutations that compromise survival during infection--is permitting fresh insight into the number and types of proteins that mammals use to defend themselves against microbes.
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Affiliation(s)
- Bruce Beutler
- Department of Immunology, Scripps Research Institute, La Jolla, California 92037, USA.
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