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Avcibas R, Vermul A, Gluhovic V, Boback N, Arroyo R, Kingma P, Isasi-Campillo M, Garcia-Ortega L, Griese M, Kuebler WM, Ochs M, Lauster D, Lopez-Rodriguez E. Multivalent, calcium-independent binding of surfactant protein A and D to sulfated glycosaminoglycans of the alveolar epithelial glycocalyx. Am J Physiol Lung Cell Mol Physiol 2024; 326:L524-L538. [PMID: 38375572 DOI: 10.1152/ajplung.00283.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 01/22/2024] [Accepted: 02/13/2024] [Indexed: 02/21/2024] Open
Abstract
Lung surfactant collectins, surfactant protein A (SP-A) and D (SP-D), are oligomeric C-type lectins involved in lung immunity. Through their carbohydrate recognition domain, they recognize carbohydrates at pathogen surfaces and initiate lung innate immune response. Here, we propose that they may also be able to bind to other carbohydrates present in typical cell surfaces, such as the alveolar epithelial glycocalyx. To test this hypothesis, we analyzed and quantified the binding affinity of SP-A and SP-D to different sugars and glycosaminoglycans (GAGs) by microscale thermophoresis (MST). In addition, by changing the calcium concentration, we aimed to characterize any consequences on the binding behavior. Our results show that both oligomeric proteins bind with high affinity (in nanomolar range) to GAGs, such as hyaluronan (HA), heparan sulfate (HS) and chondroitin sulfate (CS). Binding to HS and CS was calcium-independent, as it was not affected by changing calcium concentration in the buffer. Quantification of GAGs in bronchoalveolar lavage (BAL) fluid from animals deficient in either SP-A or SP-D showed changes in GAG composition, and electron micrographs showed differences in alveolar glycocalyx ultrastructure in vivo. Taken together, SP-A and SP-D bind to model sulfated glycosaminoglycans of the alveolar epithelial glycocalyx in a multivalent and calcium-independent way. These findings provide a potential mechanism for SP-A and SP-D as an integral part of the alveolar epithelial glycocalyx binding and interconnecting free GAGs, proteoglycans, and other glycans in glycoproteins, which may influence glycocalyx composition and structure.NEW & NOTEWORTHY SP-A and SP-D function has been related to innate immunity of the lung based on their binding to sugar residues at pathogen surfaces. However, their function in the healthy alveolus was considered as limited to interaction with surfactant lipids. Here, we demonstrated that these proteins bind to glycosaminoglycans present at typical cell surfaces like the alveolar epithelial glycocalyx. We propose a model where these proteins play an important role in interconnecting alveolar epithelial glycocalyx components.
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Affiliation(s)
- Rabia Avcibas
- Institute of Functional Anatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Anna Vermul
- Institute of Functional Anatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Vladimir Gluhovic
- Institute of Functional Anatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Nico Boback
- Core Facility Electron Microscopy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Raquel Arroyo
- Division of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
| | - Paul Kingma
- Division of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
| | - Miriam Isasi-Campillo
- Department of Biochemistry and Molecular Biology, Complutense University Madrid, Madrid, Spain
| | - Lucia Garcia-Ortega
- Department of Biochemistry and Molecular Biology, Complutense University Madrid, Madrid, Spain
| | - Matthias Griese
- Dr. von Hauner Children's Hospital, University Hospital, LMU Munich, German Center for Lung Research, Munich, Germany
| | - Wolfgang M Kuebler
- Institute of Physiology, Charité - Universitätsmedizin, Berlin, Germany
- German Center for Cardiovascular Research (DZHK), Berlin, Germany
- Keenan Research Centre, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
- Department of Surgery, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- German Center for Lung Research (DZL), Berlin, Germany
| | - Matthias Ochs
- Institute of Functional Anatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- German Center for Lung Research (DZL), Berlin, Germany
- Core Facility Electron Microscopy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Daniel Lauster
- Institute of Pharmacy, Biopharmaceuticals, Freie Universität Berlin, Berlin, Germany
| | - Elena Lopez-Rodriguez
- Institute of Functional Anatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany
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Dong S, Pang H, Li F, Hua M, Liang M, Song C. Immunoregulatory function of SP-A. Mol Immunol 2024; 166:58-64. [PMID: 38244369 DOI: 10.1016/j.molimm.2024.01.005] [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: 10/24/2023] [Revised: 12/28/2023] [Accepted: 01/08/2024] [Indexed: 01/22/2024]
Abstract
Surfactant protein A (SP-A), a natural immune molecule, plays an important role in lung health. SP-A recognizes and binds microbial surface glycogroups through the C-type carbohydrate recognition domain, and then binds corresponding cell surface receptors (such as C1qRp, CRT-CD91 complex, CD14, SP-R210, Toll-like receptor, SIRP-α, CR3, etc.) through collagen-like region, and subsequently mediates biological effects. SP-A regulates lung innate immunity by promoting surfactant absorption by alveolar type II epithelial cells and phagocytosis of pathogenic microorganisms by alveolar macrophages. SP-A also regulates lung adaptive immunity by inhibiting DC maturation, and T cell proliferation and differentiation. This article reviews latest relationships between SP-A and adaptive and intrinsic immunity.
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Affiliation(s)
- Shu Dong
- Department of Immunology, School of Laboratory Medicine, Bengbu Medical University, Anhui 233030, China; Anhui Province Key Laboratory of Immunology in Chronic Diseases, Bengbu Medical University, Anhui 233030, China
| | - Hongyuan Pang
- Department of Immunology, School of Laboratory Medicine, Bengbu Medical University, Anhui 233030, China; Anhui Province Key Laboratory of Immunology in Chronic Diseases, Bengbu Medical University, Anhui 233030, China
| | - Fan Li
- Department of Immunology, School of Laboratory Medicine, Bengbu Medical University, Anhui 233030, China; Anhui Province Key Laboratory of Immunology in Chronic Diseases, Bengbu Medical University, Anhui 233030, China
| | - Mengqing Hua
- Department of Immunology, School of Laboratory Medicine, Bengbu Medical University, Anhui 233030, China; Anhui Province Key Laboratory of Immunology in Chronic Diseases, Bengbu Medical University, Anhui 233030, China
| | - Meng Liang
- Department of Biotechnology, School of Life Science, Bengbu Medical University, Anhui 233030, China.
| | - Chuanwang Song
- Department of Immunology, School of Laboratory Medicine, Bengbu Medical University, Anhui 233030, China; Anhui Province Key Laboratory of Immunology in Chronic Diseases, Bengbu Medical University, Anhui 233030, China.
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Cedzyński M, Świerzko AS. Collectins and ficolins in neonatal health and disease. Front Immunol 2023; 14:1328658. [PMID: 38193083 PMCID: PMC10773719 DOI: 10.3389/fimmu.2023.1328658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/04/2023] [Indexed: 01/10/2024] Open
Abstract
The immune system starts to develop early in embryogenesis. However, at birth it is still immature and associated with high susceptibility to infection. Adaptation to extrauterine conditions requires a balance between colonization with normal flora and protection from pathogens. Infections, oxidative stress and invasive therapeutic procedures may lead to transient organ dysfunction or permanent damage and perhaps even death. Newborns are primarily protected by innate immune mechanisms. Collectins (mannose-binding lectin, collectin-10, collectin-11, collectin-12, surfactant protein A, surfactant protein D) and ficolins (ficolin-1, ficolin-2, ficolin-3) are oligomeric, collagen-related defence lectins, involved in innate immune response. In this review, we discuss the structure, specificity, genetics and role of collectins and ficolins in neonatal health and disease. Their clinical associations (protective or pathogenic influence) depend on a variety of variables, including genetic polymorphisms, gestational age, method of delivery, and maternal/environmental microflora.
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Affiliation(s)
- Maciej Cedzyński
- Laboratory of Immunobiology of Infections, Institute of Medical Biology, Polish Academy of Sciences, Łódź, Poland
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4
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Budani M, Auray-Blais C, Lingwood C. ATP-binding cassette transporters mediate differential biosynthesis of glycosphingolipid species. J Lipid Res 2021; 62:100128. [PMID: 34597626 PMCID: PMC8569594 DOI: 10.1016/j.jlr.2021.100128] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 08/18/2021] [Accepted: 09/03/2021] [Indexed: 01/13/2023] Open
Abstract
The cytosolic-oriented glucosylceramide (GlcCer) synthase is enigmatic, requiring nascent GlcCer translocation to the luminal Golgi membrane to access glycosphingolipid (GSL) anabolic glycosyltransferases. The mechanism by which GlcCer is flipped remains unclear. To investigate the role of GlcCer-binding partners in this process, we previously made cleavable, biotinylated, photoreactive GlcCer analogs in which the reactive nitrene was closely apposed to the GlcCer head group, while maintaining a C16-acyl chain. GlcCer-binding protein specificity was validated for both photoprobes. Using one probe, XLB, here we identified ATP-binding cassette (ABC) transporters ABCA3, ABCB4, and ABCB10 as unfractionated microsomal GlcCer-binding proteins in DU-145 prostate tumor cells. siRNA knockdown (KD) of these transporters differentially blocked GSL synthesis assessed in toto and via metabolic labeling. KD of ABCA3 reduced acid/neutral GSL levels, but increased those of LacCer, while KD of ABCB4 preferentially reduced neutral GSL levels, and KD of ABCB10 reduced levels of both neutral and acidic GSLs. Depletion of ABCA12, implicated in GlcCer transport, preferentially decreased neutral GSL levels, while ABCB1 KD preferentially reduced gangliosides, but increased neutral GSL Gb3. These results imply that multiple ABC transporters may provide distinct but overlapping GlcCer and LacCer pools within the Golgi lumen for anabolism of different GSL series by metabolic channeling. Differential ABC family member usage may fine-tune GSL biosynthesis depending on cell/tissue type. We conclude that ABC transporters provide a new tool for the regulation of GSL biosynthesis and serve as potential targets to reduce selected GSL species/subsets in diseases in which GSLs are dysregulated.
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Affiliation(s)
- Monique Budani
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Christiane Auray-Blais
- Division of Medical Genetics, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Québec, Canada
| | - Clifford Lingwood
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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5
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Li Z, Feizi T. The neoglycolipid (NGL) technology-based microarrays and future prospects. FEBS Lett 2018; 592:3976-3991. [PMID: 30074246 DOI: 10.1002/1873-3468.13217] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 07/31/2018] [Accepted: 07/31/2018] [Indexed: 11/06/2022]
Abstract
The neoglycolipid (NGL) technology is the basis of a state-of-the-art oligosaccharide microarray system, which we offer for screening analyses to the broad scientific community. We review here the sequential development of the technology and its power in pinpointing and isolating naturally occurring ligands for glycan-binding proteins (GBPs) within glycan populations. We highlight our Designer Array approach and Beam Search Array approach for generating natural glycome arrays to identify novel ligands of biological relevance. These two microarray approaches have been applied for assignments of ligands or antigens on glucan polysaccharides for effector proteins of the immune system (Dectin-1, DC-SIGN and DC-SIGNR) and carbohydrate-binding modules (CBMs) on bacterial hydrolases. We also discuss here the more recent applications to elucidate the structure of a prostate cancer- associated antigen F77 and identify ligands for adhesins of two rotaviruses, P[10] and P[19], expressed on an epithelial mucin glycoprotein.
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Affiliation(s)
- Zhen Li
- Glycosciences Laboratory, Imperial College London, UK
| | - Ten Feizi
- Glycosciences Laboratory, Imperial College London, UK
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6
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Rynkiewicz MJ, Wu H, Cafarella TR, Nikolaidis NM, Head JF, Seaton BA, McCormack FX. Differential Ligand Binding Specificities of the Pulmonary Collectins Are Determined by the Conformational Freedom of a Surface Loop. Biochemistry 2017; 56:4095-4105. [PMID: 28719181 DOI: 10.1021/acs.biochem.6b01313] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lung surfactant proteins (SPs) play critical roles in surfactant function and innate immunity. SP-A and SP-D, members of the collectin family of C-type lectins, exhibit distinct ligand specificities, effects on surfactant structure, and host defense functions despite extensive structural homology. SP-A binds to dipalmitoylphosphatidylcholine (DPPC), the major surfactant lipid component, but not phosphatidylinositol (PI), whereas SP-D shows the opposite preference. Additionally, SP-A and SP-D recognize widely divergent pathogen-associated molecular patterns. Previous studies suggested that a ligand-induced surface loop conformational change unique to SP-A contributes to lipid binding affinity. To test this hypothesis and define the structural features of SP-A and SP-D that determine their ligand binding specificities, a structure-guided approach was used to introduce key features of SP-D into SP-A. A quadruple mutant (E171D/P175E/R197N/K203D) that introduced an SP-D-like loop-stabilizing calcium binding site into the carbohydrate recognition domain was found to interconvert SP-A ligand binding preferences to an SP-D phenotype, exchanging DPPC for PI specificity, and resulting in the loss of lipid A binding and the acquisition of more avid mannan binding properties. Mutants with constituent single or triple mutations showed alterations in their lipid and sugar binding properties that were intermediate between those of SP-A and SP-D. Structures of mutant complexes with inositol or methyl-mannose revealed an attenuation of the ligand-induced conformational change relative to wild-type SP-A. These studies suggest that flexibility in a key surface loop supports the distinctive lipid binding functions of SP-A, thus contributing to its multiple functions in surfactant structure and regulation, and host defense.
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Affiliation(s)
- Michael J Rynkiewicz
- Department of Physiology and Biophysics, Boston University School of Medicine , Boston, Massachusetts 02118, United States
| | - Huixing Wu
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Cincinnati College of Medicine , Cincinnati, Ohio 45267, United States
| | - Tanya R Cafarella
- Department of Physiology and Biophysics, Boston University School of Medicine , Boston, Massachusetts 02118, United States
| | - Nikolaos M Nikolaidis
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Cincinnati College of Medicine , Cincinnati, Ohio 45267, United States
| | - James F Head
- Department of Physiology and Biophysics, Boston University School of Medicine , Boston, Massachusetts 02118, United States
| | - Barbara A Seaton
- Department of Physiology and Biophysics, Boston University School of Medicine , Boston, Massachusetts 02118, United States
| | - Francis X McCormack
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Cincinnati College of Medicine , Cincinnati, Ohio 45267, United States
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7
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The Distribution of Lectins across the Phylum Nematoda: A Genome-Wide Search. Int J Mol Sci 2017; 18:ijms18010091. [PMID: 28054982 PMCID: PMC5297725 DOI: 10.3390/ijms18010091] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 12/20/2016] [Accepted: 12/28/2016] [Indexed: 12/13/2022] Open
Abstract
Nematodes are a very diverse phylum that has adapted to nearly every ecosystem. They have developed specialized lifestyles, dividing the phylum into free-living, animal, and plant parasitic species. Their sheer abundance in numbers and presence in nearly every ecosystem make them the most prevalent animals on earth. In this research nematode-specific profiles were designed to retrieve predicted lectin-like domains from the sequence data of nematode genomes and transcriptomes. Lectins are carbohydrate-binding proteins that play numerous roles inside and outside the cell depending on their sugar specificity and associated protein domains. The sugar-binding properties of the retrieved lectin-like proteins were predicted in silico. Although most research has focused on C-type lectin-like, galectin-like, and calreticulin-like proteins in nematodes, we show that the lectin-like repertoire in nematodes is far more diverse. We focused on C-type lectins, which are abundantly present in all investigated nematode species, but seem to be far more abundant in free-living species. Although C-type lectin-like proteins are omnipresent in nematodes, we have shown that only a small part possesses the residues that are thought to be essential for carbohydrate binding. Curiously, hevein, a typical plant lectin domain not reported in animals before, was found in some nematode species.
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8
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Specific Serum Markers of IPF. IDIOPATHIC PULMONARY FIBROSIS 2016. [PMCID: PMC7120645 DOI: 10.1007/978-4-431-55582-7_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Idiopathic pulmonary fibrosis (IPF) is defined as a specific form of chronic, progressive, fibrosing interstitial pneumonia of unknown cause. It is characterized by the progressive worsening of lung function and has a poor prognosis (median survival is approximately 3 years). However, the clinical course of disease shows considerable individual variability. Therefore, it is important to monitor the clinical course and to predict prognosis for optimal therapy. Serum biomarkers are both less invasive and reproducible diagnostic tools. Useful biomarkers for patients with IPF are strongly coveted; however, to date, there are no biomarkers that are globally known. In Japan, surfactant protein (SP)-A, SP-D, and KL-6 are commonly used as serum markers of interstitial pneumonia, including IPF, in the clinical setting, and empirical data has been accumulated over 10 years. SP-A and SP-D are hydrophilic proteins and members of the collectin family. These collectins have been shown to function as host defense lectins in the lung. KL-6 is a high molecular weight glycoprotein and now classified as a human MUC1 mucin protein. These three proteins are mainly synthesized by alveolar type II cells. The mechanisms of increase for these protein levels in sera of patients with IPF are probably a combination of a loss of epithelial integrity due to injury and an increased mass of type II cells due to hyperplasia. It has been revealed that those proteins are useful for monitoring the clinical course and predicting prognosis as well as for the diagnosis of IPF. In this review article, the molecular structures and biological functions of these biomarkers are outlined, and we discuss the clinical application of these biomarkers for patients with IPF.
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Feizi T. Carbohydrate recognition in the immune system: contributions of neoglycolipid-based microarrays to carbohydrate ligand discovery. Ann N Y Acad Sci 2013; 1292:33-44. [PMID: 23834439 PMCID: PMC4260124 DOI: 10.1111/nyas.12210] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oligosaccharide sequences in glycomes of eukaryotes and prokaryotes are enormously diverse. The reasons are not fully understood, but there is an increasing number of examples of the involvement of specific oligosaccharide sequences as ligands in protein-carbohydrate interactions in health and, directly or indirectly, in every major disease, be it infectious or noninfectious. The pinpointing and characterizing of oligosaccharide ligands within glycomes has been one of the most challenging aspects of molecular cell biology, as oligosaccharides cannot be cloned and are generally available in limited amounts. This overview recounts the background to the development of a microarray system that is poised for surveying proteomes for carbohydrate-binding activities and glycomes for assigning the oligosaccharide ligands. Examples are selected by way of illustrating the potential of "designer" microarrays for ligand discovery at the interface of infection, immunity, and glycobiology. Particularly highlighted are sulfo-oligosaccharide and gluco-oligosaccharide recognition systems elucidated using microarrays.
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Affiliation(s)
- Ten Feizi
- The Glycosciences Laboratory, Department of Medicine, Imperial College London, London, United Kingdom.
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10
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11
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12
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Jing X, Espinosa EP, Perrigault M, Allam B. Identification, molecular characterization and expression analysis of a mucosal C-type lectin in the eastern oyster, Crassostrea virginica. FISH & SHELLFISH IMMUNOLOGY 2011; 30:851-858. [PMID: 21256965 DOI: 10.1016/j.fsi.2011.01.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 01/07/2011] [Accepted: 01/09/2011] [Indexed: 05/30/2023]
Abstract
Lectins are well known to actively participate in the defense functions of vertebrates and invertebrates where they play an important role in the recognition of foreign particles. They have also been reported to be involved in other processes requiring carbohydrate-lectin interactions such as symbiosis or fertilization. In this study, we report a novel putative C-type lectin (CvML) from the eastern oyster Crassostrea virginica and we investigated its involvement in oyster physiology. The cDNA of this lectin is 610 bp long encoding for a 161-residue protein. CvML presents a signal peptide and a single carbohydrate recognition domain (CRD) which contains a YPD motif and two putative conserved sites, WID and DCM, for calcium binding. CvML transcripts were expressed in mucocytes lining the epithelium of the digestive gland and the pallial organs (mantle, gills, and labial palps) but were not detected in other tissues including hemocytes. Its expression was significantly up-regulated following starvation or bacterial bath exposure but not after injection of bacteria into oyster's adductor muscle. These results highlight the potential role of CvML in the interactions between oyster and waterborne microorganisms at the pallial interfaces with possible involvement in physiological functions such as particle capture or mucosal immunity.
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Affiliation(s)
- Xing Jing
- School of Marine and Atmospheric Sciences, State University of New York, Stony Brook, NY 11794, USA
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Pales Espinosa E, Perrigault M, Allam B. Identification and molecular characterization of a mucosal lectin (MeML) from the blue mussel Mytilus edulis and its potential role in particle capture. Comp Biochem Physiol A Mol Integr Physiol 2010; 156:495-501. [DOI: 10.1016/j.cbpa.2010.04.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 04/02/2010] [Accepted: 04/06/2010] [Indexed: 10/19/2022]
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Casals C. Role of Surfactant Protein a (SP-A)/Lipid Interactions for SP-A Functions in the Lung. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/15513810109168821] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Schwab U, Rohde KH, Wang Z, Chess PR, Notter RH, Russell DG. Transcriptional responses of Mycobacterium tuberculosis to lung surfactant. Microb Pathog 2009; 46:185-93. [PMID: 19272305 PMCID: PMC2748912 DOI: 10.1016/j.micpath.2008.12.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Revised: 12/19/2008] [Accepted: 12/30/2008] [Indexed: 11/27/2022]
Abstract
This study uses microarray analyses to examine gene expression profiles for Mycobacterium tuberculosis (Mtb) induced by exposure in vitro to bovine lung surfactant preparations that vary in apoprotein content: (i) whole lung surfactant (WLS) containing the complete mixture of endogenous lipids and surfactant proteins (SP)-A, -B, -C, and -D; (ii) extracted lung surfactant (CLSE) containing lipids plus SP-B and -C; (iii) column-purified surfactant lipids (PPL) containing no apoproteins, and (iv) purified human SP-A. Exposure to WLS evoked a multitude of transcriptional responses in Mtb, with 52 genes up-regulated and 23 genes down-regulated at 30min exposure, plus 146 genes up-regulated and 27 genes down-regulated at 2h. Notably, WLS rapidly induced several membrane-associated lipases that presumptively act on surfactant lipids as substrates, and a large number of genes involved in the synthesis of phthiocerol dimycocerosate (PDIM), a cell wall component known to be important in macrophage interactions and Mtb virulence. Exposure of Mtb to CLSE, PPL, or purified SP-A caused a substantially weaker transcriptional response (=20 genes were induced) suggesting that interactions among multiple lipid-protein components of WLS may contribute to its effects on Mtb transcription.
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Affiliation(s)
- Ute Schwab
- Department of Microbiology and Immunology, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, USA.
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Kishore U, Greenhough TJ, Waters P, Shrive AK, Ghai R, Kamran MF, Bernal AL, Reid KBM, Madan T, Chakraborty T. Surfactant proteins SP-A and SP-D: structure, function and receptors. Mol Immunol 2005; 43:1293-315. [PMID: 16213021 DOI: 10.1016/j.molimm.2005.08.004] [Citation(s) in RCA: 376] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Accepted: 08/23/2005] [Indexed: 12/11/2022]
Abstract
Surfactant proteins, SP-A and SP-D, are collagen-containing C-type (calcium dependent) lectins called collectins, which contribute significantly to surfactant homeostasis and pulmonary immunity. These highly versatile innate immune molecules are involved in a range of immune functions including viral neutralization, clearance of bacteria, fungi and apoptotic and necrotic cells, down regulation of allergic reaction and resolution of inflammation. Their basic structures include a triple-helical collagen region and a C-terminal homotrimeric lectin or carbohydrate recognition domain (CRD). The trimeric CRDs can recognize carbohydrate or charge patterns on microbes, allergens and dying cells, while the collagen region can interact with receptor molecules present on a variety of immune cells in order to initiate clearance mechanisms. Studies involving gene knock-out mice, murine models of lung hypersensitivity and infection, and functional characterization of cell surface receptors have revealed the diverse roles of SP-A and SP-D in the control of lung inflammation. A recently proposed model based on studies with the calreticulin-CD91 complex as a receptor for SP-A and SP-D has suggested an anti-inflammatory role for SP-A and SP-D in naïve lungs which would help minimise the potential damage that continual low level exposure to pathogens, allergens and apoptosis can cause. However, when the lungs are overwhelmed with exogenous insults, SP-A and SP-D can assume pro-inflammatory roles in order to complement pulmonary innate and adaptive immunity. This review is an update on the structural and functional aspects of SP-A and SP-D, with emphasis on their roles in controlling pulmonary infection, allergy and inflammation. We also try to put in perspective the controversial subject of the candidate receptor molecules for SP-A and SP-D.
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Affiliation(s)
- Uday Kishore
- Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK.
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Casals C, García-Verdugo I. Molecular and Functional Properties of Surfactant Protein A. LUNG BIOLOGY IN HEALTH AND DISEASE 2005. [DOI: 10.1201/b14169-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Abstract
Surfactant protein-A enhances the phagocytosis and killing of many pathogens, although studying this effect in an assortment of models and different experimental protocols has sometimes yielded conflicting results. In this report, using the human THP-1 cell line as the primary phagocytic cell, we systematically examined several models where microspheres, Staphylococcus aureus and Escherichia coli were used for targets. We found that SP-A derived from human lavage appeared to enhance phagocytosis by two different mechanisms; by SP-A binding of the target to enhance its recognition and subsequent phagocytosis and by a direct SP-A stimulatory effect on the phagocyte itself. Both SP-A mechanisms occurred with different targets in the same experimental system and the SP-A effects were qualitatively (but not quantitatively) comparable in several human cell lines (THP-1, U937, Mono-Mac-6). We also found that the SP-A effects were abrogated when SP-A was combined with surfactant lipids, but the lipids did not affect the basal level of phagocytosis or phagocytosis by mechanisms not involving SP-A. Moreover, the stimulatory effect of SP-A was pH-dependent and appeared to be independent of several other phagocytic mechanisms, including those mediated by Fc receptors and mannose receptor.
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Affiliation(s)
- Jianqiang Ding
- Department of Cellular Physiology, Pennsylvania State College of Medicine, P.O. Box 850, Hershey, PA 17033, USA
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19
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Lingwood CA, Mylvaganam M. Lipid modulation of glycosphingolipid (GSL) receptors: soluble GSL mimics provide new probes of GSL receptor function. Methods Enzymol 2003; 363:264-83. [PMID: 14579581 DOI: 10.1016/s0076-6879(03)01057-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Clifford A Lingwood
- Research Institute, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G IX8, Canada
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20
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Abstract
Due to their diversity and external location on cell membranes, glycans, as glycocalyx components, are key elements in eukaryotic cell, tissue, and organ homeostasis. Although information on the lung glycocalyx is scarce, this article aims to review, discuss, and summarize what is known about bronchoalveolar glycocalyx composition, mainly the sialic acids. It was deemed relevant, however, to make a brief introductory overview of the cell glycocalyx and its particular development in epithelial cells. After that, follows a summary of the evolution of the knowledge regarding the bronchoalveolar glycocalyx composition throughout the years, particularly its morphological features. Since sialic acids are located terminally on the bronchoalveolar lining cells' glycocalyx and play crucial roles, we focused mainly on the existing lung histochemical and biochemical data of these sugar residues, as well as their evolution throughout lung development. The functions of the lung glycocalyx sialic acids are discussed and interpretations of their roles analyzed, including those related to the negative overall superficial shield provided by these molecules. The increasing presence of these sugar residues throughout postnatal lung development should be regarded as pivotal in the development and maintenance of a dynamic bronchoalveolar architecture, supporting the normal histophysiology of the respiratory system. The case for a profound knowledge of lung glycocalyx--given its potential to provide answers to serious clinical problems--is made with particular reference to cystic fibrosis. Finally, concluding remarks and perspectives for future research in this field are put forth.
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Affiliation(s)
- Maria de Fátima Martins
- Institute of Histology and Embryology and Center for Histophysiology, Experimental Pathology and Developmental Biology, Faculty of Medicine, University of Coimbra, Portugal
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21
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Abstract
The lung collectins, SP-A and SP-D, are important components of the innate immune response to microbial challenge and participate in other aspects of immune and inflammatory regulation within the lung. Both proteins bind to surface structures expressed by a wide variety of microorganisms and have the capacity to modulate multiple leukocyte functions, including the enhanced internalization and killing of certain microorganisms in vitro. In addition, transgenic mice with deficiencies in SP-A and SP-D show defective or altered responses to challenge with bacterial, fungal, and viral microorganisms and to bacterial lipopolysaccharides in vivo. Thus collectins could play particularly important roles in settings of inadequate or impaired specific immunity, and acquired alterations in the levels of active collectins within the airspaces and distal airways may increase susceptibility to infection.
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Affiliation(s)
- E Crouch
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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22
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Affiliation(s)
- U Kishore
- Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Headington, Oxford OX3 9DS, UK
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23
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Chiba H, Sano H, Iwaki D, Murakami S, Mitsuzawa H, Takahashi T, Konishi M, Takahashi H, Kuroki Y. Rat mannose-binding protein a binds CD14. Infect Immun 2001; 69:1587-92. [PMID: 11179331 PMCID: PMC98060 DOI: 10.1128/iai.69.3.1587-1592.2001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipopolysaccharide (LPS) has been known to induce inflammation by interacting with CD14, which serves as a receptor for LPS. Mannose-binding protein (MBP) belongs to the collectin subgroup of the C-type lectin superfamily, along with surfactant proteins SP-A and SP-D. We have recently demonstrated that SP-A modulates LPS-induced cellular responses by interaction with CD14 (H. Sano, H. Sohma, T. Muta, S. Nomura, D. R. Voelker, and Y. Kuroki, J. Immunol. 163:387-395, 2000) and that SP-D also interacts with CD14 (H. Sano, H. Chiba, D. Iwaki, H. Sohma, D. R. Voelker, and Y. Kuroki, J. Biol. Chem. 275:22442-22451, 2000). In this study, we examined whether MBP, a collectin highly homologous to SP-A and SP-D, could bind CD14. Recombinant rat MBP-A bound recombinant human soluble CD14 in a concentration-dependent manner. Its binding was not inhibited in the presence of excess mannose or EDTA. MBP-A bound deglycosylated CD14 treated with N-glycosidase F, neuraminidase, and O-glycosidase, indicating that MBP-A interacts with the peptide portion of CD14. Since LPS was also a ligand for the collectins, we compared the characteristics of binding of MBP-A to LPS with those of binding to CD14. MBP-A bound to lipid A from Salmonella enterica serovar Minnesota and rough LPS (S. enterica serovar Minnesota Re595 and Escherichia coli J5, Rc), but not to smooth LPS (E. coli O26:B6 and O111:B4). Unlike CD14 binding, EDTA and excess mannose attenuated the binding of MBP-A to rough LPS. From these results, we conclude that CD14 is a novel ligand for MBP-A and that MBP-A utilizes a different mechanism for CD14 recognition from that for LPS.
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Affiliation(s)
- H Chiba
- Department of Biochemistry, Sapporo Medical University School of Medicine, Chuo-ku, Sapporo 060-8556, Japan
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24
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Kogelberg H, Lawson AM, Muskett FW, Carruthers RA, Feizi T. Expression in Escherichia coli, folding in vitro, and characterization of the carbohydrate recognition domain of the natural killer cell receptor NKR-P1A. Protein Expr Purif 2000; 20:10-20. [PMID: 11035945 DOI: 10.1006/prep.2000.1257] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
NKR-P1A is a homodimeric type II transmembrane protein of the C-type lectin family found on natural killer (NK) cells and NK-like T cells and is an activator of cytotoxicity. Toward structure determination by NMR, the recombinant carbohydrate-recognition domain (CRD) of NKR-P1A has been expressed in high-yield in Escherichia coli and folded in vitro. The purified protein behaves as a monomer in size-exclusion chromatography and is bound by the conformation-sensitive antibody, 3.2.3, indicating a folded structure. A polypeptide tag at the N-terminus is selectively cleaved from the CRD after limited trypsin digestion in further support of a compact folded structure. The disulfide bonds have been identified by peptide mapping and electrospray mass spectrometry. These are characteristic of a long form CRD. The 1D NMR spectrum of the unlabeled CRD and the 2D HSQC spectrum of the (15)N-labeled CRD are those of a folded protein. Chemical shifts of H(alpha) and NH protons indicate a considerable amount of beta-strand structure. Successful folding in the absence of Ca(2+), coupled with the lack of chemical shift changes upon addition of Ca(2+), suggests that the NKR-P1A-CRD may not be a Ca(2+)-binding protein.
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Affiliation(s)
- H Kogelberg
- The Glycosciences Laboratory, Imperial College School of Medicine, Northwick Park Campus, Harrow, Middlesex, United Kingdom.
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25
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Sano H, Chiba H, Iwaki D, Sohma H, Voelker DR, Kuroki Y. Surfactant proteins A and D bind CD14 by different mechanisms. J Biol Chem 2000; 275:22442-51. [PMID: 10801802 DOI: 10.1074/jbc.m001107200] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Surfactant proteins A (SP-A) and D (SP-D) are lung collectins that are constituents of the innate immune system of the lung. Recent evidence (Sano, H., Sohma, H., Muta, T., Nomura, S., Voelker, D. R., and Kuroki, Y. (1999) J. Immunol. 163, 387-395) demonstrates that SP-A modulates lipopolysaccharide (LPS)-induced cellular responses by direct interaction with CD14. In this report we examined the structural elements of the lung collectins involved in CD14 recognition and the consequences for CD14/LPS interaction. Rat SP-A and SP-D bound CD14 in a concentration-dependent manner. Mannose and EDTA inhibited SP-D binding to CD14 but did not decrease SP-A binding. The SP-A binding to CD14 was completely blocked by a monoclonal antibody that binds to the SP-A neck domain but only partially blocked by an antibody that binds to the SP-A lectin domain. SP-A but not SP-D bound to deglycosylated CD14. SP-D decreased CD14 binding to both smooth and rough LPS, whereas SP-A enhanced CD14 binding to rough LPS and inhibited binding to smooth LPS. SP-A also altered the migration profile of LPS on a sucrose density gradient in the presence of CD14. From these results, we conclude that 1) lung collectins bind CD14, 2) the SP-A neck domain and SP-D lectin domain participate in CD14 binding, 3) SP-A recognizes a peptide component and SP-D recognizes a carbohydrate moiety of CD14, and 4) lung collectins alter LPS/CD14 interactions.
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Affiliation(s)
- H Sano
- Department of Biochemistry, Sapporo Medical University School of Medicine, Sapporo, Japan
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26
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Childs RA, Galustian C, Lawson AM, Dougan G, Benwell K, Frankel G, Feizi T. Recombinant soluble human CD69 dimer produced in Escherichia coli: reevaluation of saccharide binding. Biochem Biophys Res Commun 1999; 266:19-23. [PMID: 10581158 DOI: 10.1006/bbrc.1999.1762] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We reevaluate here an earlier report of monosaccharide binding by the C-type lectin-like, leukocyte surface protein CD69 in the form of a recombinant soluble dimer, and we examine polysaccharide binding by the protein. We have expressed in Escherichia coli a new construct of the extracellular part (Q(65)-K(199)) of human CD69. We describe the folding in vitro to produce, in good yield, the protein in a soluble, disulphide-linked, dimeric form, and the results of binding experiments with monosaccharides: glucose, galactose, mannose, fucose, N-acetylglucosamine, and N-acetylgalactosamine, linked to bovine serum albumin. Monosaccharide-binding signals are not detectable. Among the polysaccharides, heparin, chondroitin sulphates A, B, and C, fucoidan, and dextran sulphate, CD69 dimer gives a weak binding signal with fucoidan.
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MESH Headings
- Amino Acid Sequence
- Antigens, CD/biosynthesis
- Antigens, CD/chemistry
- Antigens, CD/isolation & purification
- Antigens, CD/metabolism
- Antigens, Differentiation, T-Lymphocyte/biosynthesis
- Antigens, Differentiation, T-Lymphocyte/chemistry
- Antigens, Differentiation, T-Lymphocyte/isolation & purification
- Antigens, Differentiation, T-Lymphocyte/metabolism
- Binding Sites
- Blotting, Western
- Dimerization
- Disulfides/metabolism
- Epitopes/biosynthesis
- Epitopes/chemistry
- Epitopes/isolation & purification
- Epitopes/metabolism
- Escherichia coli/genetics
- Humans
- Hydrogen-Ion Concentration
- Lectins, C-Type
- Molecular Sequence Data
- Molecular Weight
- Monosaccharides/metabolism
- Peptide Fragments/biosynthesis
- Peptide Fragments/chemistry
- Peptide Fragments/isolation & purification
- Peptide Fragments/metabolism
- Polysaccharides/metabolism
- Protein Binding
- Protein Denaturation
- Protein Folding
- Recombinant Fusion Proteins/biosynthesis
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/isolation & purification
- Recombinant Fusion Proteins/metabolism
- Solubility
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Affiliation(s)
- R A Childs
- Imperial College School of Medicine, Northwick Park Campus, Harrow, Middlesex, HA1 3UJ, United Kingdom
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27
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Kogelberg H, Montero E, Bay S, Lawson AM, Feizi T. Re-evaluation of Monosaccharide Binding Property of Recombinant Soluble Carbohydrate Recognition Domain of the Natural Killer Cell Receptor NKR-P1A. J Biol Chem 1999. [DOI: 10.1016/s0021-9258(19)51904-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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28
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Leteux C, Stoll MS, Childs RA, Chai W, Vorozhaikina M, Feizi T. Influence of oligosaccharide presentation on the interactions of carbohydrate sequence-specific antibodies and the selectins. Observations with biotinylated oligosaccharides. J Immunol Methods 1999; 227:109-19. [PMID: 10485259 DOI: 10.1016/s0022-1759(99)00077-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This study was aimed at investigating the efficacy of presentation of biotinylated oligosaccharides on streptavidin-coated microwells for interactions with (a) three monoclonal antibodies directed at sialyl-Lewisa (Le(a)) or sulfo-Le(a)-related sequences, and (b) the endothelium-leukocyte adhesion molecules, the E-, L- and P-selectins which recognize both the sulfo- and sialyl-Le(a) series. With the antibodies it was observed that if the biotinylated oligosaccharide incorporated the entire antigenic determinant, and additional saccharide length was not included, the biotinyl tag spacer length was a critical factor in the strength of the binding signal. If oligosaccharide chain beyond the determinant was included, the biotinyl tag spacer length was less important. The E-selectin binding data with the biotinylated sialyl- and sulfo-oligosaccharides were in overall accord with previous knowledge. With the L- and P-selectins, however, unexpectedly low binding signals were elicited by biotinyl sulfo-Le(a) sequences relative to those with the sialyl-analogs. This suppression was more pronounced with the rodent than the human L-selectin. Such differential availabilities of oligosaccharides displayed on streptavidin may relate to biological situations, such as the differential reactivities of the three selectins with a given oligosaccharide ligand presented on different carrier proteins, or on different O-glycan cores on mucin-type glycoproteins.
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Affiliation(s)
- C Leteux
- The Glycosciences Laboratory, Imperial College School of Medicine, Northwick Park Hospital, Harrow, Middlesex, UK
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29
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Pasula R, Wright JR, Kachel DL, Martin WJ. Surfactant protein A suppresses reactive nitrogen intermediates by alveolar macrophages in response to Mycobacterium tuberculosis. J Clin Invest 1999; 103:483-90. [PMID: 10021456 PMCID: PMC408094 DOI: 10.1172/jci2991] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Mycobacterium tuberculosis attaches to, enters, and replicates within alveolar macrophages (AMs). Our previous studies suggest that surfactant protein A (SP-A) can act as a ligand in the attachment of M. tuberculosis to AMs. Reactive nitrogen intermediates (RNIs) play a significant role in the killing of mycobacteria. We have demonstrated that RNI levels generated by AMs were significantly increased when interferon-gamma-primed AMs were incubated with M. tuberculosis. However, the RNI levels were significantly suppressed in the presence of SP-A (10 microg/ml). The specificity of SP-A's effect was demonstrated by the use of F(ab')2 fragments of anti-SP-A monoclonal antibodies and by the use of mannosyl-BSA, which blocked the suppression of RNI levels by SP-A. Furthermore, incubation of deglycosylated SP-A with M. tuberculosis failed to suppress RNI by AMs, suggesting that the oligosaccharide component of SP-A, which binds to M. tuberculosis, is necessary for this effect. These results show that SP-A-mediated binding of M. tuberculosis to AMs significantly decreased RNI levels, suggesting that this may be one mechanism by which M. tuberculosis diminishes the cytotoxic response of activated AMs.
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Affiliation(s)
- R Pasula
- Division of Pulmonary, Allergy, Critical Care and Occupational Medicine, Department of Internal Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202-2879, USA
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30
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Abstract
The lung is an organ with a large inner surface that is continuously in contact with the environment. Infection of this organ is prevented by several mechanisms. A recently described defence system is collectin-mediated innate immunity of the lung. Collectins are multimeric proteins characterized by carbohydrate recognition domains bound to collagen stalks. Surfactant protein (SP)-A and SP-D are collectins that are present in the epithelial lining fluid of the lung. SP-A interacts with viruses, bacteria and fungi. Furthermore, SP-A binds to various other inhaled glycoconjugates. SP-A receptors on phagocytic cells have been described that are important to ensure rapid pathogen clearance. This innate defence system of the lung may be particularly important during infections in young children when the acquired immune system has not yet become fully established. Also in later life SP-A could be very important to prevent the lungs from infections by pathogens not previously encountered. In addition, SP-A may limit the inflammatory response in the lungs, thus preventing damage to the delicate lung epithelia. Recently, evidence was presented that SP-A may modulate the allergic response to various glycosylated inhaled antigens. The presence of SP-A (and SP-D) in other organs indicates that these collectins may have a general role in mucosal immunity. In this review the interactions of SP-A with a variety of pathogens and its implications are discussed.
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Affiliation(s)
- H P Haagsman
- Laboratory of Veterinary Biochemistry, and Graduate School Animal Health, Utrecht University, P.O. Box 80.176, 3508 TD Utrecht, The Netherlands.
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31
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McCormack FX. Structure, processing and properties of surfactant protein A. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1408:109-31. [PMID: 9813267 DOI: 10.1016/s0925-4439(98)00062-3] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Surfactant protein A (SP-A) is a highly ordered, oligomeric glycoprotein that is secreted into the airspaces of the lung by the pulmonary epithelium. The in vitro activities of protein suggest diverse roles in pulmonary host defense and surfactant homeostasis, structure and surface activity. Functional mapping of SP-A using directed mutagenesis has identified domains which interact with surfactant phospholipids, alveolar type II cells and microbes. Recently developed genetically manipulated animal models are beginning to clarify the critical physiological roles for SP-A in the normal lung, and in the pathophysiology of pulmonary disease.
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Affiliation(s)
- F X McCormack
- Division of Pulmonary and Critical Care Medicine, University of Cincinnati College of Medicine, 231 Bethesda Ave., Cincinnati, OH 45267-0564, USA.
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32
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Tino MJ, Wright JR. Interactions of surfactant protein A with epithelial cells and phagocytes. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1408:241-63. [PMID: 9813349 DOI: 10.1016/s0925-4439(98)00071-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Surfactant protein A (SP-A) has been shown to bind to and regulate the functions of both alveolar type II cells and immune cells including alveolar macrophages. The interaction of SP-A with type II cells has been shown in vitro to inhibit lipid secretion and to promote the uptake of lipid by these cells and these observations led to the hypothesis that SP-A plays an important role in regulating surfactant turnover and metabolism. The finding that mice made deficient in SP-A by homologous recombination (SP-A -/- mice) have relatively normal surfactant pool sizes has raised the possibility that either redundant mechanisms function in vivo to keep pool sizes normal in the absence of SP-A or that the in vitro findings are not significant in the context of the whole, unstressed animal. The interaction of SP-A with immune cells has been shown to affect a variety of responses which, in general, function to promote host defense against infection. Although SP-A receptors have been identified, additional studies will be required to elucidate the mechanism of interaction of SP-A with these cells and the relative importance of the different receptors in SP-A mediated regulation of cell function.
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Affiliation(s)
- M J Tino
- Department of Cell Biology, Duke University Medical Center, Box 3709, 438 Nanaline Duke, Durham, NC 27710, USA
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33
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Abstract
The surfactant-associated proteins SP-A and SP-D are members of a family of collagenous host defense lectins, designated collectins. There is increasing evidence that these pulmonary epithelial-derived proteins are important components of the innate immune response to microbial challenge, and that they participate in other aspects of immune and inflammatory regulation within the lung. The collectins bind to glycoconjugates and/or lipid moieties expressed by a wide variety of microorganisms and certain other organic particles in vitro. Although binding may facilitate microbial clearance through aggregation or other direct effects on the organism, SP-A and SP-D also have the capacity to modulate leukocyte function and, in some circumstances, to enhance their killing of microorganisms. The biologic activity of cell wall components, such as gram-negative bacterial polysaccharides, may be altered by interactions with collectins. Complementary or cooperative interactions between SP-A and SP-D could contribute to the efficiency of this defense system. Collectins may play particularly important roles in settings of inadequate or impaired specific immunity. Acquired or genetic alterations in the levels of active proteins within the airspaces and distal airways may increase susceptibility to infection.
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Affiliation(s)
- E C Crouch
- Department of Pathology, Washington University School of Medicine, St. Louis, Missouri, USA.
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34
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Ruano ML, Nag K, Worthman LA, Casals C, Pérez-Gil J, Keough KM. Differential partitioning of pulmonary surfactant protein SP-A into regions of monolayers of dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylcholine/dipalmitoylphosphatidylglycerol. Biophys J 1998; 74:1101-9. [PMID: 9512012 PMCID: PMC1299462 DOI: 10.1016/s0006-3495(98)77828-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The interaction of the pulmonary surfactant protein SP-A fluorescently labeled with Texas Red (TR-SP-A) with monolayers of dipalmitoylphosphatidylcholine (DPPC) and DPPC/dipalmitoylphosphatidylglycerol 7:3 w/w has been investigated. The monolayers were spread on aqueous subphases containing TR-SP-A. TR-SP-A interacted with the monolayers of DPPC to accumulate at the boundary regions between liquid condensed (LC) and liquid expanded (LE) phases. Some TR-SP-A appeared in the LE phase but not in the LC phase. At intermediate surface pressures (10-20 mN/m), the protein caused the occurrence of more, smaller condensed domains, and it appeared to be excluded from the monolayers at surface pressure in the range of 30-40 mN/m. TR-SP-A interaction with DPPC/dipalmitoylphosphatidylglycerol monolayers was different. The protein did not appear in either LE or LC but only in large aggregates at the LC-LE boundary regions, a distribution visually similar to that of fluorescently labeled concanavalin A adsorbed onto monolayers of DPPC. The observations are consistent with a selectivity of interaction of SP-A with DPPC and for its accumulation in boundaries between LC and LE phase.
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Affiliation(s)
- M L Ruano
- Departmento de Bioquímica, Facultad de Biología, Universidad Complutense, Madrid, Spain
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35
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Sano H, Kuroki Y, Honma T, Ogasawara Y, Sohma H, Voelker DR, Akino T. Analysis of chimeric proteins identifies the regions in the carbohydrate recognition domains of rat lung collectins that are essential for interactions with phospholipids, glycolipids, and alveolar type II cells. J Biol Chem 1998; 273:4783-9. [PMID: 9468543 DOI: 10.1074/jbc.273.8.4783] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Pulmonary surfactant proteins A (SP-A) and D (SP-D) are collectins in the C-type lectin superfamily. SP-A binds to dipalmitoylphosphatidylcholine and galactosylceramide, and it regulates the uptake and secretion of surfactant lipids by alveolar type II cells. In contrast, SP-D binds to phosphatidylinositol (PI) and glucosylceramide (GlcCer). We investigated the functional region in the carbohydrate recognition domain of rat SP-A and SP-D that is involved in binding lipids and interacting with alveolar type II cells by using chimeric proteins. Chimeras ad3, ad4, and ad5 were constructed with SP-A/SP-D splice junctions at Gly194/Glu321, Gln173/Thr300, and Met134/Cys261, respectively. All three chimeras lost SP-A-specific functions. Chimeras ad3, ad4, and ad5 bound to PI with increasing activity. In contrast, chimeras ad3 and ad4 did not bind to GlcCer, whereas ad5 avidly bound this lipid. From these results, we conclude that 1) the SP-A region of Glu195-Phe228 is required for lipid and type II cell interactions, 2) the SP-D region of Cys261-Phe355 is required for optimal lipid interactions, and 3) the structural requirement for the binding of SP-D to PI is different from that for GlcCer.
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Affiliation(s)
- H Sano
- Department of Biochemistry, Sapporo Medical University School of Medicine, Sapporo 060, Japan
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36
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Kuroki Y, Honma T, Chiba H, Sano H, Saitoh M, Ogasawara Y, Sohma H, Akino T. A novel type of binding specificity to phospholipids for rat mannose-binding proteins isolated from serum and liver. FEBS Lett 1997; 414:387-92. [PMID: 9315725 DOI: 10.1016/s0014-5793(97)01022-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mannose-binding protein (MBP) belongs to the collectin subgroup of C-type lectins with specificity for mannose and N-acetylglucosamine sugars. We investigated whether rat MBPs isolated from serum (S-MBP) and liver (L-MBP) interact with phospholipids using antibody against each MBP. Both S- and L-MBPs bound to phosphatidylinositol coated onto microtiter wells in a concentration- and a Ca2+-dependent manner. L-MBP also bound to phosphatidylglycerol and weakly to phosphatidylserine. MBPs interacted with liposomes composed of these lipids. S- and L-MBPs bound to phosphatidylinositol 4-monophosphate. L-MBP also bound to cardiolipin. These results provide evidence for a novel type of ligand binding specificity for MBPs, and raise the possibility that phospholipids are ligands for collectins.
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Affiliation(s)
- Y Kuroki
- Department of Biochemistry, Sapporo Medical University School of Medicine, Japan.
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37
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Yamaji T, Miyake Y, Kozutsumi Y, Kawasaki T. Neutral glycosphingolipids induce cell-cell aggregation of a variety of hematopoietic cell lines. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 247:21-9. [PMID: 9249004 DOI: 10.1111/j.1432-1033.1997.t01-1-00021.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Exogenous neutral glycosphingolipids induced homotypic cell-cell aggregation of a variety of hematopoietic cell lines. A mouse cytotoxic T cell line, CTLL-2, was chosen to study the neutral glycosphingolipid-induced aggregation. Among neutral glycosphingolipids tested, galactosylceramide (GalCer) and glucosylceramide (GlcCer) were potent inducers, followed by lactosylceramide (LacCer); globotriaosylceramide (Gb3Cer) and neolactotetraosylceramide (nLc4Cer) were less effective. GalCer that contained a non-hydroxy fatty acid was more efficient than GalCer containing an alpha-hydroxy fatty acid. The minimum concentration of GalCer containing a non-hydroxy fatty acid that induced aggregation was 1 microM, and maximum aggregation occurred at 10-20 microM within 24 h. Cytochalasin B and a mixture of sodium azide and 2-deoxyglucose inhibited the aggregation, whereas cycloheximide, actinomycin D, and colchicine did not. Aggregated and dispersed cells, which were designated as competent cells, re-aggregated in the absence of neutral glycosphingolipids. Anti-GalCer polyclonal antibody inhibited GalCer-induced reaggregation. Furthermore, competent cells bound and aggregated non-competent cells in the absence of neutral glycosphingolipids. Cell-cell aggregatign was similar for CTLL-2 cells and the other hematopoietic cells that were tested. These findings suggest that the neutral glycosphingolipid-induced cell-cell aggregation of CTLL-2 cells was mediated by heterophilic interaction(s) between glycosphingolipids and other cell surface components. These properties are shared by a variety of hematopoietic cell lines.
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Affiliation(s)
- T Yamaji
- Department of Biological Chemistry, Faculty of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Japan
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Johansson J, Curstedt T. Molecular structures and interactions of pulmonary surfactant components. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 244:675-93. [PMID: 9108235 DOI: 10.1111/j.1432-1033.1997.00675.x] [Citation(s) in RCA: 209] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The dominating functional property of pulmonary surfactant is to reduce the surface tension at the alveolar air/liquid interface, and thereby prevent the lungs from collapsing at the end of expiration. In addition, the system exhibits host-defense properties. Insufficient amounts of pulmonary surfactant in premature infants causes respiratory distress syndrome, a serious threat which nowadays can be effectively treated by airway instillation of surfactant preparations. Surfactant is a mixture of many molecular species, mainly phospholipids and specific proteins, surfactant protein A (SP-A), SP-B, SP-C and SP-D. SP-A and SP-D are water-soluble and belong to the collectins, a family of large multimeric proteins which structurally exhibit collagenous/lectin hybrid properties and functionally are Ca2+-dependent carbohydrate binding proteins involved in innate host-defence functions. SP-A and SP-D also bind lipids and SP-A is involved in organization of alveolar surfactant phospholipids. SP-B belongs to another family of proteins, which includes also lipid-interacting polypeptides with antibacterial and lytic properties. SP-B is a 17.4-kDa homodimer and each subunit contains three intrachain disulphides and has been proposed to contain four amphipathic helices oriented pairwise in an antiparallel fashion. SP-A, SP-B and SP-D all have been detected also in the gastrointestinal tract. SP-C, in contrast, appears to be a unique protein with extreme structural and stability properties and to exist exclusively in the lungs. SP-C is a lipopeptide containing covalently linked palmitoyl chains and is folded into a 3.7-nm alpha-helix with a central 2.3-nm all-aliphatic part, making it perfectly suited to interact in a transmembranous way with a fluid bilayer composed of dipalmitoylglycerophosphocholine, the main component of surfactant. Homozygous genetic deficiency of proSP-B causes lethal respiratory distress soon after birth and is associated with aberrant processing of the precursor of SP-C. This review focuses on the chemical composition, structures and interactions of the pulmonary surfactant, in particular the associated proteins.
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Affiliation(s)
- J Johansson
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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Chroneos ZC, Abdolrasulnia R, Whitsett JA, Rice WR, Shepherd VL. Purification of a cell-surface receptor for surfactant protein A. J Biol Chem 1996; 271:16375-83. [PMID: 8663107 DOI: 10.1074/jbc.271.27.16375] [Citation(s) in RCA: 149] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In the present report we have characterized the binding of surfactant protein A (SP-A) to bone marrow-derived macrophages, U937 cells, alveolar macrophages, and type II epithelial cells. The binding of SP-A to all cell types is Ca2+-dependent and trypsin-sensitive, but type II cells express distinct Ca2+-independent binding sites. The binding of SP-A to macrophages is independent of known cell surface carbohydrate-specific receptors and of glycoconjugate binding sites on the surface of the cells and is distinct from binding to C1q receptors. Based on ligand blot analysis, both type II cells and macrophages express a 210-kDa SP-A-binding protein. The 210-kDa protein was purified to apparent homogeneity from U937 macrophage membranes using affinity chromatography with noncovalently immobilized surfactant protein A, and was purified from rat lung by differential detergent and salt extraction of isolated rat lung membranes. Polyclonal antibodies against the rat lung SP-A-binding protein inhibit binding of SP-A to both type II cells and macrophages, indicating that the 210-kDa protein is expressed on the cell surface. The polyclonal antibodies also block the SP-A-mediated inhibition of phospholipid secretion by type II cells, indicating that the 210-kDa protein is a functional cell-surface receptor on type II cells. In a separate report we have determined that antibodies to the SP-A receptor block the SP-A-mediated uptake of Mycobacterium bovis, indicating that the macrophage SP-A receptor is involved in SP-A-mediated clearance of pathogens.
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Affiliation(s)
- Z C Chroneos
- Division of Pulmonary Biology, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA
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Ogasawara Y, Voelker DR. Altered carbohydrate recognition specificity engineered into surfactant protein D reveals different binding mechanisms for phosphatidylinositol and glucosylceramide. J Biol Chem 1995; 270:14725-32. [PMID: 7782337 DOI: 10.1074/jbc.270.24.14725] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Pulmonary surfactant protein D (SP-D) is a member of the collection subgroup of the C-type lectin superfamily that binds glycosylated lipids such as phosphatidylinositol (PI) and glucosylceramide (GlcCer). We have previously reported that the carbohydrate recognition domain of SP-D plays an essential role in lipid binding. However, it is unclear how the carbohydrate binding property of SP-D contributes to the lipid binding. To clarify the relationship between the lectin property and the lipid binding activity of rat SP-D, we expressed wild-type recombinant rat SP-D (rSP-D) and a mutant form of the protein with substitutions Glu-321-->Gln and Asn-323-->Asp (SP-DE321Q,N323D) in CHO-K1 cells. The indicated mutations have previously been shown to change the carbohydrate binding specificity of surfactant protein A and mannose-binding protein from mannose > galactose to the converse. rSP-D expressed in mammalian cells was essentially identical to native rat SP-D in its lipid and carbohydrate binding properties. In contrast, SP-DE321Q,N323D was unable to bind GlcCer, but retained binding activity toward PI liposomes and solid-phase PI. The efficiency of SP-DE321Q,N323D binding to PI liposome was approximately 50% of that of rSP-D in the presence of 5 mM Ca2+, but equivalent at 20 mM Ca2+. Carbohydrates competed for SP-D binding to PI such that maltose > galactose for rSP-D, and the order was reversed for SP-DE321Q,N323D. Furthermore, SP-DE321Q,N323D could bind to digalactosyldiacylglycerol more effectively than rSP-D. These results suggest the following. 1) The carbohydrate binding specificity of SP-DE321Q,N323D was changed from a mannose-glucose type to a galactose type; 2) the GlcCer binding property of SP-D is closely related to its sugar binding activity; and 3) the PI binding activity is not completely dependent on its carbohydrate binding specificity.
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Affiliation(s)
- Y Ogasawara
- Lord and Taylor Laboratory for Lung Biochemistry, Anna Perahia Adatto Clinical Laboratories, USA
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Reid KB, Turner MW. Mammalian lectins in activation and clearance mechanisms involving the complement system. SPRINGER SEMINARS IN IMMUNOPATHOLOGY 1994; 15:307-26. [PMID: 8153870 DOI: 10.1007/bf01837363] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
CRP and the mammalian lectins containing collagen-like structure (collectins) can clearly participate in a variety of antibody-independent recognition and clearance mechanisms which result in the neutralisation and elimination of pathogenic organisms (Fig. 2). Only CRP and MBP appear to have the capacity to activate complement, and while all the collectins (MBP, SP-A, SP-D and conglutinin) can utilise the C1q receptor, only conglutinin shows specificity for iC3b. The C-type lectin domains in the globular heads of the collectins have the capacity to recognise a range of specific carbohydrate structures which are found on the surfaces of pathogens commonly associated with infections in blood, lung and amniotic fluids. The proposed presentation of the carbohydrate-collectin complex to C1q receptors, via the collagen-like regions in the collectins is an attractive hypothesis for the triggering of protective mechanisms and there are already a number of publications which support this view. However, the precise manner by which these collagen 'stalks' interact with the C1q receptor and the complete characterisation of the receptor on a variety of different cell types remains to be elucidated. Similarly, whether or not there is a role for any of these lectins in autoimmunity/immunopathology has not, as yet, been addressed.
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Affiliation(s)
- K B Reid
- Department of Biochemistry, University of Oxford, UK
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Kuroki Y, McCormack FX, Ogasawara Y, Mason RJ, Voelker DR. Epitope mapping for monoclonal antibodies identifies functional domains of pulmonary surfactant protein A that interact with lipids. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)43951-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Pison U, Max M, Neuendank A, Weissbach S, Pietschmann S. Host defence capacities of pulmonary surfactant: evidence for 'non-surfactant' functions of the surfactant system. Eur J Clin Invest 1994; 24:586-99. [PMID: 7828630 DOI: 10.1111/j.1365-2362.1994.tb01110.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The most well characterized function of pulmonary surfactant is its ability to reduce surface tension at the alveolar air-liquid interface, thereby preventing lung collapse. However, several lines of evidence suggest that surfactant may also have 'non-surfactant' functions: specific components of surfactant (proteins and phospholipids) may interact with different alveolar cells, inhaled particles and micro-organisms modulating pulmonary host defence systems. SP-A, the most abundant surfactant protein, binds to alveolar macrophages via a specific surface receptor with high affinity [128]. Such binding effects the release of reactive oxygen species from resident alveolar macrophages if SP-A is properly presented to the target cell. SP-A also stimulates chemotaxis of alveolar macrophages [142], and serves as an opsonin in the phagocytosis of herpes simplex virus [161] Candida tropicalis [138] and various bacteria [137]. In addition, SP-A enhances the uptake of particles by monocytes and culture-derived macrophages [140] and improves bacterial killing. SP-D, another hydrophobic surfactant-associated protein, might interact with alveolar macrophages as well, stimulating the release of oxygen radicals [148], while for the hydrophilic surfactant proteins SP-B and SP-C no macrophage interactions have been described so far. SP-A and SP-D are members of the so-called 'collectins', pattern recognition molecules involved in first line defence. While some surfactant proteins appear to stimulate certain macrophage defence functions, surfactant phospholipids seem to inhibit those of lymphocytes. Suppressed lymphocyte functions include lymphoproliferation in response to mitogens and alloantigens, B cell immunoglobulin production and natural killer cell cytotoxicity. Concerning surfactant's phospholipid composition phosphatidylglycerol is more suppressive than phosphatidylcholine on a molar basis [38]. Bovine surfactant has an immunosuppressive effect on the development of hypersensitivity pneumonitis in a guinea pig model [150]. Despite these interesting observations, several important questions concerning the interactions of surfactant components with pulmonary host defence systems remain unanswered. Sufficient host defence in the lungs works through various humoral-cellular systems in conjunction with the specific anatomy of the airways and the gas exchange surface--how does the surfactant system fit into this network? Surfactant and alveolar cells are both altered during lung injury--is there a relationship between alveolar cells from RDS patients and the endogenous surfactant isolated from such patients? How does exogenous surfactant as used for substitution therapy modulate the defence system of the host? Some of those artificial surfactants have been shown to inhibit the endotoxin-alveolar macrophages, PMNs and monocytes including IL-1, IL-6 and TNF [139,152].(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- U Pison
- Department of Anesthesiology and Intensive Care Medicine, Universitätsklinikum Rudolf Virchow, Freie Universität Berlin, Germany
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Green PJ, Feizi T, Stoll MS, Thiel S, Prescott A, McConville MJ. Recognition of the major cell surface glycoconjugates of Leishmania parasites by the human serum mannan-binding protein. Mol Biochem Parasitol 1994; 66:319-28. [PMID: 7808481 DOI: 10.1016/0166-6851(94)90158-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Activation of complement on the surface of parasitic protozoa of the genus Leishmania appears to be important for parasite infectivity in the mammalian host, as it allows these parasites to attach to and invade macrophages via their surface complement receptors. Serum mannan-binding protein (MBP) is a known activator of complement. Therefore, in the present study, we have investigated whether serum MBP binds to live Leishmania parasites, and to mannose-containing saccharides derived from the parasite cell surface. We have observed by fluorescence microscopy that biotinylated MBP binds to the surface of L. major and L. mexicana promastigotes. At this developmental stage the parasites are coated by a mannose-containing lipophosphoglycan (LPG). We have observed that radioiodinated MBP binds in a mannose-inhibitable manner to purified LPG which has been immobilized in plastic microwells, as well as to purified mannose-terminating di-, tri- and tetrasaccharide fragments ('cap' structures) which have been released by mild acid hydrolysis from the outer chains of the LPG, converted into neoglycolipids and resolved by thin-layer chromatography. 125I-MBP also binds in the chromatogram-binding assay to the mannose-containing glycoinositol-phospholipids that are expressed in high copy number on both the promastigote and the intracellular amastigote stages of most Leishmania species. These data suggest that MBP has the potential to opsonize the major developmental stages of Leishmania parasites, and provide a possible mechanism for the antibody-independent activation of complement on their surface.
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Affiliation(s)
- P J Green
- Glycoconjugates Section, MRC Clinical Research Centre, Harrow, Middlesex, UK
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46
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Sane AC, Young SL. The stimulation of cellular phospholipid uptake by surfactant apoproteins. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1213:107-12. [PMID: 8011672 DOI: 10.1016/0005-2760(94)90228-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Surfactant recycling by alveolar cells is influenced by the surfactant apoproteins SP-A, -B and -C (Wright, J.R. and Dobbs, L.G. (1991) Annu. Rev. Physiol. 53, 395-414). Alveolar macrophages and type II cells, but not lung fibroblasts, were reported to accumulate surfactant phospholipid in the presence of SP-A in low calcium medium, although high affinity binding of SP-A to alveolar macrophages and type II cells showed an absolute requirement for mM calcium. SP-B, one of two very hydrophobic surfactant proteins, stimulated phospholipid uptake by type II cells and Chinese hamster lung fibroblasts suspended in Dulbecco's minimum essential medium containing mM Ca2+. We postulated that calcium influences cellular phospholipid uptake stimulated by SP-A or SP-B. We used isolated rat alveolar and peritoneal macrophages and Vero cells, an African Green Monkey kidney fibroblast cell line, and studied the effect of calcium concentrations ranging from 2 microM to 2 mM on cellular uptake of liposomes containing 3H-labeled phosphatidylcholine. For alveolar and peritoneal macrophages, increasing calcium concentration enhanced SP-A stimulation of phospholipid uptake. SP-A did not stimulate phosphatidylcholine uptake by Vero cells. SP-B stimulated phosphatidylcholine uptake by alveolar and peritoneal macrophages and Vero cells independent of the calcium concentration. These studies demonstrate that the enhancement of phospholipid uptake in alveolar and peritoneal macrophages by SP-A, but not SP-B is augmented by calcium.
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Affiliation(s)
- A C Sane
- Department of Internal Medicine, Veterans Affairs, Medical Center, Durham, NC
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Bezouska K, Vlahas G, Horváth O, Jinochová G, Fiserová A, Giorda R, Chambers W, Feizi T, Pospísil M. Rat natural killer cell antigen, NKR-P1, related to C-type animal lectins is a carbohydrate-binding protein. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(19)89481-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Christa L, Felin M, Morali O, Simon MT, Lasserre C, Brechot C, Sève AP. The human HIP gene, overexpressed in primary liver cancer encodes for a C-type carbohydrate binding protein with lactose binding activity. FEBS Lett 1994; 337:114-8. [PMID: 8276102 DOI: 10.1016/0014-5793(94)80640-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
HIP was originally identified as a gene expression in primary liver cancers, and in normal tissues such as pancreas and small intestine. Based on gene data base homologies, the HIP protein should consist of a signal peptide linked to a single carbohydrate recognition domain. To test this hypothesis HIP and the putative carbohydrate recognition domain encoded by the last 138 C-terminal amino acids, were expressed as glutathione-S-transferase proteins (GST-HIP and GST-HIP-142, respectively). Both recombinant proteins were purified by a single affinity purification step from bacterial lysates and their ability to bind saccharides coupled to trisacryl GF 2000M were tested. Our results show that HIP and HIP-142 proteins bind to lactose, moreover the binding requires divalent cations. Thus the HIP protein is a lactose-binding lectin with the characteristics of a C-type carbohydrate recognition domain of 138 amino acids in the C-terminal region.
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Affiliation(s)
- L Christa
- INSERM U370, CHU Necker, Paris, France
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Feizi T, Stoll MS, Yuen CT, Chai W, Lawson AM. Neoglycolipids: probes of oligosaccharide structure, antigenicity, and function. Methods Enzymol 1994; 230:484-519. [PMID: 8139514 DOI: 10.1016/0076-6879(94)30030-5] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- T Feizi
- Glycoconjugates Section, MRC Clinical Research Centre, Harrow, Middlesex, United Kingdom
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