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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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2
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The lung surfactant activity probed with molecular dynamics simulations. Adv Colloid Interface Sci 2022; 304:102659. [PMID: 35421637 DOI: 10.1016/j.cis.2022.102659] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 03/18/2022] [Accepted: 03/31/2022] [Indexed: 01/17/2023]
Abstract
The surface of pulmonary alveolar subphase is covered with a mixture of lipids and proteins. This lung surfactant plays a crucial role in lung functioning. It shows a complex phase behavior which can be altered by the interaction with third molecules such as drugs or pollutants. For studying multicomponent biological systems, it is of interest to couple experimental approach with computational modelling yielding atomic-scale information. Simple two, three, or four-component model systems showed to be useful for getting more insight in the interaction between lipids, lipids and proteins or lipids and proteins with drugs and impurities. These systems were studied theoretically using molecular dynamic simulations and experimentally by means of the Langmuir technique. A better understanding of the structure and behavior of lung surfactants obtained from this research is relevant for developing new synthetic surfactants for efficient therapies, and may contribute to public health protection.
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3
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Lettau M, Timm S, Dittmayer C, Lopez-Rodriguez E, Ochs M. The ultrastructural heterogeneity of lung surfactant revealed by serial section electron tomography: Insights into the 3D architecture of human tubular myelin. Am J Physiol Lung Cell Mol Physiol 2022; 322:L873-L881. [PMID: 35438000 DOI: 10.1152/ajplung.00020.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Weibel's hypothetical 3D model in 1966 provided first ultrastructural details into tubular myelin (TM), a unique, complex surfactant subtype found in the hypophase of the alveolar lining layer. Although initial descriptions by electron microscopy (EM) were already published in the 1950s, a uniform morphological differentiation from other intraalveolar surfactant subtypes is still missing and potential structure-function relationships remain enigmatic. Technical developments in volume EM methods now allow a more detailed reinvestigation. To address unanswered ultrastructural questions, we analyzed ultrathin sections of humanized SP-A1/SP-A2 co-expressing mouse as well as human lung samples by conventional transmission EM. We combined these 2D information with 3D analysis of single- and dual-axis electron tomography of serial sections for high z-resolution (in a range of a few nm) and extended volumes of up to 1 µm total z-information. This study reveals that TM constitutes a heterogeneous surfactant organization mainly comprised of distorted parallel membrane planes with local intersections, which are distributed all over the TM substructure. These intersecting membrane planes form, among other various polygons, the well-known 2D "lattice", respectively 3D quadratic tubules, which in many analyzed spots of human alveoli appear to be less abundant than also observed non-concentric 3D lamellae. The additional application of serial section electron tomography to conventional transmission EM demonstrates a high heterogeneity of TM membrane networks, which indicates dynamic transformations between its substructures. Our method provides an ideal basis for further in and ex vivo structural analyses of surfactant under various conditions at nanometer scale.
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Affiliation(s)
- Marie Lettau
- Institute of Functional Anatomy, Charité , Berlin, Germany
| | - Sara Timm
- Core Facility Electron Microscopy, Charité , Berlin, Germany
| | | | | | - Matthias Ochs
- Institute of Functional Anatomy, Charité , Berlin, Germany.,German Center for Lung Research, Berlin, Germany
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4
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Floros J, Tsotakos N. Differential Regulation of Human Surfactant Protein A Genes, SFTPA1 and SFTPA2, and Their Corresponding Variants. Front Immunol 2021; 12:766719. [PMID: 34917085 PMCID: PMC8669794 DOI: 10.3389/fimmu.2021.766719] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 11/02/2021] [Indexed: 11/26/2022] Open
Abstract
The human SFTPA1 and SFTPA2 genes encode the surfactant protein A1 (SP-A1) and SP-A2, respectively, and they have been identified with significant genetic and epigenetic variability including sequence, deletion/insertions, and splice variants. The surfactant proteins, SP-A1 and SP-A2, and their corresponding variants play important roles in several processes of innate immunity as well in surfactant-related functions as reviewed elsewhere [1]. The levels of SP-A have been shown to differ among individuals both under baseline conditions and in response to various agents or disease states. Moreover, a number of agents have been shown to differentially regulate SFTPA1 and SFTPA2 transcripts. The focus in this review is on the differential regulation of SFTPA1 and SFTPA2 with primary focus on the role of 5′ and 3′ untranslated regions (UTRs) and flanking sequences on this differential regulation as well molecules that may mediate the differential regulation.
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Affiliation(s)
- Joanna Floros
- Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, PA, United States.,Department of Obstetrics and Gynecology, The Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Nikolaos Tsotakos
- School of Science, Engineering, and Technology, The Pennsylvania State University - Harrisburg, Middletown, PA, United States
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5
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Loney RW, Brandner B, Dagan MP, Smith PN, Roche M, Fritz JR, Hall SB, Tristram-Nagle SA. Changes in membrane elasticity caused by the hydrophobic surfactant proteins correlate poorly with adsorption of lipid vesicles. SOFT MATTER 2021; 17:3358-3366. [PMID: 33630985 PMCID: PMC8016726 DOI: 10.1039/d0sm02223c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
To establish how the hydrophobic surfactant proteins, SP-B and SP-C, promote adsorption of lipids to an air/water interface, we used X-ray diffuse scattering (XDS) to determine an order parameter of the lipid chains (Sxray) and the bending modulus of the lipid bilayers (KC). Samples contained different amounts of the proteins with two sets of lipids. Dioleoylphosphatidylcholine (DOPC) provided a simple, well characterized model system. The nonpolar and phospholipids (N&PL) from extracted calf surfactant provided the biological mix of lipids. For both systems, the proteins produced changes in Sxray that correlated well with KC. The dose-response to the proteins, however, differed. Small amounts of protein generated large decreases in Sxray and KC for DOPC that progressed monotonically. The changes for the surfactant lipids were erratic. Our studies then tested whether the proteins produced correlated effects on adsorption. Experiments measured the initial fall in surface tension during adsorption to a constant surface area, and then expansion of the interface during adsorption at a constant surface tension of 40 mN m-1. The proteins produced a sigmoidal increase in the rate of adsorption at 40 mN m-1 for both lipids. The results correlated poorly with the changes in Sxray and KC in both cases. Disordering of the lipid chains produced by the proteins, and the softening of the bilayers, fail to explain how the proteins promote adsorption of lipid vesicles.
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Affiliation(s)
- Ryan W Loney
- Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon 97239, USA.
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6
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Fritz JR, Loney RW, Hall SB, Tristram-Nagle S. Suppression of L α/L β Phase Coexistence in the Lipids of Pulmonary Surfactant. Biophys J 2020; 120:243-253. [PMID: 33347885 DOI: 10.1016/j.bpj.2020.12.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/17/2020] [Accepted: 12/07/2020] [Indexed: 12/23/2022] Open
Abstract
To determine how different constituents of pulmonary surfactant affect its phase behavior, we measured wide-angle x-ray scattering (WAXS) from oriented bilayers. Samples contained the nonpolar and phospholipids (N&PL) obtained from calf lung surfactant extract (CLSE), which also contains the hydrophobic surfactant proteins SP-B and SP-C. Mixtures with different ratios of N&PL and CLSE provided the same set of lipids with different amounts of the proteins. At 37°C, N&PL by itself forms coexisting Lα and Lβ phases. In the Lβ structure, the acyl chains of the phospholipids occupy an ordered array that has melted by 40°C. This behavior suggests that the Lβ composition is dominated by dipalmitoyl phosphatidylcholine (DPPC), which is the most prevalent component of CLSE. The Lβ chains, however, lack the tilt of the Lβ' phase formed by pure DPPC. At 40°C, WAXS also detects an additional diffracted intensity, the location of which suggests a correlation among the phospholipid headgroups. The mixed samples of N&PL with CLSE show that increasing amounts of the proteins disrupt both the Lβ phase and the headgroup correlation. With physiological levels of the proteins in CLSE, both types of order are absent. These results with bilayers at physiological temperatures indicate that the hydrophobic surfactant proteins disrupt the ordered structures that have long been considered essential for the ability of pulmonary surfactant to sustain low surface tensions. They agree with prior fluorescence micrographic results from monomolecular films of CLSE, suggesting that at physiological temperatures, any ordered phase is likely to be absent or occupy a minimal interfacial area.
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Affiliation(s)
- Jonathan R Fritz
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Ryan W Loney
- Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon
| | - Stephen B Hall
- Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon.
| | - Stephanie Tristram-Nagle
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania.
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7
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Loney RW, Panzuela S, Chen J, Yang Z, Fritz JR, Dell Z, Corradi V, Kumar K, Tieleman DP, Hall SB, Tristram-Nagle SA. Location of the Hydrophobic Surfactant Proteins, SP-B and SP-C, in Fluid-Phase Bilayers. J Phys Chem B 2020; 124:6763-6774. [PMID: 32600036 DOI: 10.1021/acs.jpcb.0c03665] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The hydrophobic surfactant proteins, SP-B and SP-C, promote rapid adsorption by the surfactant lipids to the surface of the liquid that lines the alveolar air sacks of the lungs. To gain insights into the mechanisms of their function, we used X-ray diffuse scattering (XDS) and molecular dynamics (MD) simulations to determine the location of SP-B and SP-C within phospholipid bilayers. Initial samples contained the surfactant lipids from extracted calf surfactant with increasing doses of the proteins. XDS located protein density near the phospholipid headgroup and in the hydrocarbon core, presumed to be SP-B and SP-C, respectively. Measurements on dioleoylphosphatidylcholine (DOPC) with the proteins produced similar results. MD simulations of the proteins with DOPC provided molecular detail and allowed direct comparison of the experimental and simulated results. Simulations used conformations of SP-B based on other members of the saposin-like family, which form either open or closed V-shaped structures. For SP-C, the amino acid sequence suggests a partial α-helix. Simulations fit best with measurements of XDS for closed SP-B, which occurred at the membrane surface, and SP-C oriented along the hydrophobic interior. Our results provide the most definitive evidence yet concerning the location and orientation of the hydrophobic surfactant proteins.
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Affiliation(s)
- Ryan W Loney
- Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon 97239, United States
| | - Sergio Panzuela
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada.,Department of Theoretical Physics and Condensed Matter, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Jespar Chen
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Zimo Yang
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Jonathan R Fritz
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Zachary Dell
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Valentina Corradi
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Kamlesh Kumar
- Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon 97239, United States
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Stephen B Hall
- Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon 97239, United States
| | - Stephanie A Tristram-Nagle
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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8
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Influence of the type of congenital heart defects on epithelial lining fluid composition in infants undergoing cardiac surgery with cardiopulmonary bypass. Pediatr Res 2018; 83:791-797. [PMID: 29281616 DOI: 10.1038/pr.2017.326] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 11/30/2017] [Indexed: 12/20/2022]
Abstract
BackgroundIn children with congenital heart disease (CHD), altered pulmonary circulation compromises gas exchange. Moreover, pulmonary dysfunction is a complication of cardiac surgery with cardiopulmonary bypass (CPB). No data are available on the effect of different CHDs on lung injury. The aim of this study was to analyze epithelial lining fluid (ELF) surfactant composition in children with CHD.MethodsTracheal aspirates (TAs) from 72 CHD children (age 2.9 (0.4-5.7) months) were obtained before and after CPB. We measured ELF phospholipids, surfactant proteins A and B (SP-A, SP-B), albumin, and myeloperoxidase activity. TAs from 12 infants (age 1.0 (0.9-2.9) months) with normal heart/lung served as controls.ResultsHeart defects were transposition of great arteries (19), tetralogy of Fallot (TOF, 20), atrial/ventricular septal defect (ASD/VSD, 22), and hypoplastic left heart syndrome (11). Increased levels of ELF SP-B were found in all defects, increased myeloperoxidase activity in all except the TOF, and increased levels of ELF albumin and SP-A only in ASD/VSD patients. Postoperatively, ELF findings remained unchanged except for a further increase in myeloperoxidase activity.ConclusionELF composition has distinctive patterns in different CHD. We speculate that a better knowledge of the ELF biochemical changes may help to prevent respiratory complications.
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9
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Abstract
Three pulmonary disease conditions result from the accumulation of phospholipids in the lung. These conditions are the human lung disease known as pulmonary alveolar proteinosis, the lipoproteinosis that arises in the lungs of rats during acute silicosis, and the phospholipidoses induced by numerous cationic amphiphilic therapeutic agents. In this paper, the status of phospholipid metabolism in the lungs during the process of each of these lung conditions has been reviewed and possible mechanisms for their establishment are discussed. Pulmonary alveolar proteinosis is characterized by the accumulation of tubular myelin-like multilamellated structures in the alveoli and distal airways of patients. These structures appear to be formed by a process of spontaneous assembly involving surfactant protein A and surfactant phospholipids. Structures similar to tubular myelin-like multilamellated structures can be seen in the alveoli of rats during acute silicosis and, as with the human condition, both surfactant protein A and surfactant phospholipids accumulate in the alveoli. Excessive accumulation of surfactant protein A and surfactant phospholipids in the alveoli could arise from their overproduction and hypersecretion by a subpopulation of Type II cells that are activated by silica, and possibly other agents. Phospholipidoses caused by cationic amphiphilic therapeutic agents arise as a result of their inhibition of phospholipid catabolism. Inhibition of phospholipases results in the accumulation of phospholipids in the cytoplasm of alveolar macrophages and other cells. While inhibition of phospholipases by these agents undoubtedly occurs, there are many anomalous features, such as the accumulation of extracellular phospholipids and surfactant protein A, that cannot be accounted for by this simplistic hypothesis.
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Affiliation(s)
- Gary E. R. Hook
- Biochemical Pathology Group, Laboratory of Pulmonary Pathobiology, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, North Carolina 27709
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10
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Patrikainen MS, Pan P, Barker HR, Parkkila S. Altered gene expression in the lower respiratory tract of Car6 (-/-) mice. Transgenic Res 2016; 25:649-64. [PMID: 27209317 DOI: 10.1007/s11248-016-9961-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 05/13/2016] [Indexed: 12/13/2022]
Abstract
From birth, the respiratory tract mucosa is exposed to various chemical, physical, and microbiological stress factors. Efficient defense mechanisms and strictly regulated renewal systems in the mucosa are thus required. Carbonic anhydrase VI (CA VI) is the only secreted isoenzyme of the α-CA gene family. It is transported in high concentrations in saliva and milk into the alimentary tract where it contributes to optimal pH homeostasis. Earlier study of transcriptomic responses of Car6 (-/-) mice has shown changes in the response to oxidative stress and brown fat cell differentiation in the submandibular gland. It has been suggested that CA VI delivered to the mucosal surface of the bronchiolar epithelium is an essential factor in defense and renewal of the lining epithelium. In this study, the transcriptional effects of CA VI deficiency were investigated in both trachea and lung of Car6 (-/-) mice using a cDNA microarray analysis. Functional clustering of the results indicated significant changes of gene transcription in the lower airways. The altered biological processes included antigen transport by M-cells, potassium transport, muscle contraction, and thyroid hormone synthesis. Immunohistochemical staining confirmed the absence of CA VI in the submandibular gland of Car6 (-/-) mice. Immunostaining of the trachea and lung samples revealed no differences between the knockout and wild type groups nor were any morphological changes observed. The present findings can help us to recognize novel functions for CA VI-one of the major protein constituents of saliva and milk.
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Affiliation(s)
| | - Peiwen Pan
- School of Medicine, University of Tampere, 33014, Tampere, Finland.,Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Harlan R Barker
- School of Medicine, University of Tampere, 33014, Tampere, Finland
| | - Seppo Parkkila
- School of Medicine, University of Tampere, 33014, Tampere, Finland.,Fimlab Ltd, Tampere University Hospital, 33520, Tampere, Finland
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11
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Aiyelabegan HT, Zaidi SSZ, Fanuel S, Eatemadi A, Ebadi MTK, Sadroddiny E. Albumin-based biomaterial for lung tissue engineering applications. INT J POLYM MATER PO 2016. [DOI: 10.1080/00914037.2016.1180610] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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12
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Chavarha M, Loney RW, Rananavare SB, Hall SB. Hydrophobic surfactant proteins strongly induce negative curvature. Biophys J 2016; 109:95-105. [PMID: 26153706 DOI: 10.1016/j.bpj.2015.05.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 04/23/2015] [Accepted: 05/28/2015] [Indexed: 01/31/2023] Open
Abstract
The hydrophobic surfactant proteins SP-B and SP-C greatly accelerate the adsorption of vesicles containing the surfactant lipids to form a film that lowers the surface tension of the air/water interface in the lungs. Pulmonary surfactant enters the interface by a process analogous to the fusion of two vesicles. As with fusion, several factors affect adsorption according to how they alter the curvature of lipid leaflets, suggesting that adsorption proceeds via a rate-limiting structure with negative curvature, in which the hydrophilic face of the phospholipid leaflets is concave. In the studies reported here, we tested whether the surfactant proteins might promote adsorption by inducing lipids to adopt a more negative curvature, closer to the configuration of the hypothetical intermediate. Our experiments used x-ray diffraction to determine how the proteins in their physiological ratio affect the radius of cylindrical monolayers in the negatively curved, inverse hexagonal phase. With binary mixtures of dioleoylphosphatidylethanolamine (DOPE) and dioleoylphosphatidylcholine (DOPC), the proteins produced a dose-related effect on curvature that depended on the phospholipid composition. With DOPE alone, the proteins produced no change. With an increasing mol fraction of DOPC, the response to the proteins increased, reaching a maximum 50% reduction in cylindrical radius at 5% (w/w) protein. This change represented a doubling of curvature at the outer cylindrical surface. The change in spontaneous curvature, defined at approximately the level of the glycerol group, would be greater. Analysis of the results in terms of a Langmuir model for binding to a surface suggests that the effect of the lipids is consistent with a change in the maximum binding capacity. Our findings show that surfactant proteins can promote negative curvature, and support the possibility that they facilitate adsorption by that mechanism.
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Affiliation(s)
- Mariya Chavarha
- Department of Biochemistry & Molecular Biology, Oregon Health & Science University, Portland, Oregon; Department of Medicine, Oregon Health & Science University, Portland, Oregon; Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, Oregon
| | - Ryan W Loney
- Department of Biochemistry & Molecular Biology, Oregon Health & Science University, Portland, Oregon; Department of Medicine, Oregon Health & Science University, Portland, Oregon; Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, Oregon
| | | | - Stephen B Hall
- Department of Biochemistry & Molecular Biology, Oregon Health & Science University, Portland, Oregon; Department of Medicine, Oregon Health & Science University, Portland, Oregon; Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, Oregon.
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13
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Beck-Broichsitter M, Ruppert C, Schmehl T, Günther A, Seeger W. Biophysical inhibition of pulmonary surfactant function by polymeric nanoparticles: role of surfactant protein B and C. Acta Biomater 2014; 10:4678-4684. [PMID: 25087869 DOI: 10.1016/j.actbio.2014.07.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 06/13/2014] [Accepted: 07/22/2014] [Indexed: 10/25/2022]
Abstract
The current study investigated the mechanisms involved in the process of biophysical inhibition of pulmonary surfactant by polymeric nanoparticles (NP). The minimal surface tension of diverse synthetic surfactants was monitored in the presence of bare and surface-decorated (i.e. poloxamer 407) sub-100 nm poly(lactide) NP. Moreover, the influence of NP on surfactant composition (i.e. surfactant protein (SP) content) was studied. Dose-elevations of SP advanced the biophysical activity of the tested surfactant preparation. Surfactant-associated protein C supplemented phospholipid mixtures (PLM-C) were shown to be more susceptible to biophysical inactivation by bare NP than phospholipid mixture supplemented with surfactant protein B (PLM-B) and PLM-B/C. Surfactant function was hindered owing to a drastic depletion of the SP content upon contact with bare NP. By contrast, surface-modified NP were capable of circumventing unwanted surfactant inhibition. Surfactant constitution influences the extent of biophysical inhibition by polymeric NP. Steric shielding of the NP surface minimizes unwanted NP-surfactant interactions, which represents an option for the development of surfactant-compatible nanomedicines.
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14
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Karbani N, Dodagatta-Marri E, Qaseem AS, Madhukaran P, Waters P, Tsolaki AG, Madan T, Kishore U. Purification of native surfactant protein SP-A from pooled amniotic fluid and bronchoalveolar lavage. Methods Mol Biol 2014; 1100:257-272. [PMID: 24218266 DOI: 10.1007/978-1-62703-724-2_21] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Surfactant protein SP-A is a hydrophilic glycoprotein, similar to SP-D, which plays an important role in pulmonary surfactant homeostasis and innate immunity. SP-A is actively expressed in the alveolar type II cells and Clara cells. Their basic structure consists of triple-helical collagen region and a C-terminal carbohydrate recognition domain (CRD). By binding to the infectious microbes, SP-A (like SP-D) are involved in pathogen opsonization and agglutination and subsequent clearance of the microorganism, via recruitment of phagocytic cells via receptors for the collagen region. SP-A has also been localized at extra-pulmonary sites such as salivary epithelium, amniotic fluid, prostate glands, and semen. The presence of SP-A in fetal and maternal tissue and amniotic fluid suggests it is involved in pregnancy and labor. Native SP-A can be purified from amniotic fluid and bronchiolar lavage fluid (BALF) via affinity chromatography. In addition, we also report here a procedure to express and purify a recombinant form of trimeric CRD in Escherichia coli. The availability of highly pure native SP-A and CRD region can be central to studies that examine the diverse roles that SP-A play in surfactant homeostasis, pulmonary infection and inflammation and pregnancy.
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Affiliation(s)
- Najmunisa Karbani
- Centre for Infection, Immunity and Disease Mechanisms, Biosciences, School of Health Sciences and Social Care, Brunel University, London, UK
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15
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Beck-Broichsitter M, Ruppert C, Schmehl T, Günther A, Seeger W. Biophysical inhibition of synthetic vs. naturally-derived pulmonary surfactant preparations by polymeric nanoparticles. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:474-81. [DOI: 10.1016/j.bbamem.2013.10.016] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 10/16/2013] [Accepted: 10/21/2013] [Indexed: 12/24/2022]
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16
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Sarker M, Jackman D, Booth V. Lung surfactant protein A (SP-A) interactions with model lung surfactant lipids and an SP-B fragment. Biochemistry 2011; 50:4867-76. [PMID: 21553841 PMCID: PMC3104520 DOI: 10.1021/bi200167d] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Surfactant protein A (SP-A) is the most abundant protein component of lung surfactant, a complex mixture of proteins and lipids. SP-A performs host defense activities and modulates the biophysical properties of surfactant in concerted action with surfactant protein B (SP-B). Current models of lung surfactant mechanism generally assume SP-A functions in its octadecameric form. However, one of the findings of this study is that when SP-A is bound to detergent and lipid micelles that mimic lung surfactant phospholipids, it exists predominantly as smaller oligomers, in sharp contrast to the much larger forms observed when alone in water. These investigations were carried out in sodium dodecyl sulfate (SDS), dodecylphosphocholine (DPC), lysomyristoylphosphatidylcholine (LMPC), lysomyristoylphosphatidylglycerol (LMPG), and mixed LMPC + LMPG micelles, using solution and diffusion nuclear magnetic resonance (NMR) spectroscopy. We have also probed SP-A’s interaction with Mini-B, a biologically active synthetic fragment of SP-B, in the presence of micelles. Despite variations in Mini-B’s own interactions with micelles of different compositions, SP-A is found to interact with Mini-B in all micelle systems and perhaps to undergo a further structural rearrangement upon interacting with Mini-B. The degree of SP-A–Mini-B interaction appears to be dependent on the type of lipid headgroup and is likely mediated through the micelles, rather than direct binding.
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Affiliation(s)
- Muzaddid Sarker
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, Canada
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17
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Loney RW, Anyan WR, Biswas SC, Rananavare SB, Hall SB. The accelerated late adsorption of pulmonary surfactant. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:4857-66. [PMID: 21417351 PMCID: PMC3074574 DOI: 10.1021/la1049259] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 02/22/2011] [Indexed: 05/17/2023]
Abstract
Adsorption of pulmonary surfactant to an air-water interface lowers surface tension (γ) at rates that initially decrease progressively, but which then accelerate close to the equilibrium γ. The studies here tested a series of hypotheses concerning mechanisms that might cause the late accelerated drop in γ. Experiments used captive bubbles and a Wilhelmy plate to measure γ during adsorption of vesicles containing constituents from extracted calf surfactant. The faster fall in γ reflects faster adsorption rather than any feature of the equation of state that relates γ to surface concentration (Γ). Adsorption accelerates when γ reaches a critical value rather than after an interval required to reach that γ. The hydrophobic surfactant proteins (SPs) represent key constituents, both for reaching the γ at which the acceleration occurs and for producing the acceleration itself. The γ at which rates of adsorption increase, however, is unaffected by the Γ of protein in the films. In the absence of the proteins, a phosphatidylethanolamine, which, like the SPs, induces fusion of the vesicles with the interfacial film, also causes adsorption to accelerate. Our results suggest that the late acceleration is characteristic of adsorption by fusion of vesicles with the nascent film, which proceeds more favorably when the Γ of the lipids exceeds a critical value.
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Affiliation(s)
- Ryan W. Loney
- Departments of Biochemistry and Molecular Biology, Medicine, and Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon 97239-3098, United States
| | - Walter R. Anyan
- Departments of Biochemistry and Molecular Biology, Medicine, and Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon 97239-3098, United States
| | - Samares C. Biswas
- Departments of Biochemistry and Molecular Biology, Medicine, and Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon 97239-3098, United States
| | - Shankar B. Rananavare
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, United States
| | - Stephen B. Hall
- Departments of Biochemistry and Molecular Biology, Medicine, and Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon 97239-3098, United States
- Address: Pulmonary and Critical Care Medicine, Mail Code UHN-67, Oregon Health & Science University, Portland, OR 97239-3098. Telephone: 503-494-6667. E-mail:
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18
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Breuiller-Fouché M, Dubois O, Sediki M, Garcia-Verdugo I, Palaniyar N, Tanfin Z, Chissey A, Cabrol D, Charpigny G, Mehats C. Secreted surfactant protein A from fetal membranes induces stress fibers in cultured human myometrial cells. Am J Physiol Endocrinol Metab 2010; 298:E1188-97. [PMID: 20233942 DOI: 10.1152/ajpendo.00746.2009] [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: 11/22/2022]
Abstract
In the present study, we investigated the ability of human fetal membranes (amnion and choriodecidua) to regulate human maternal uterine cell functions through the secretion of surfactant protein (SP)-A and SP-D at the end of pregnancy. We detected the expression of both SP-A (SP-A1 and SP-A2) and SP-D by quantitative reverse transcription polymerase chain reaction. Immunohistochemistry revealed that human fetal membranes expressed both SP-A and SP-D. By Western blot analysis, we demonstrated that SP-A protein expression was predominant in choriodecidua, whereas the amnion predominantly expressed SP-D. Only the secretion of SP-A was evidenced in the culture supernatants of amnion and choriodecidua explants by immunodot blot and confirmed by Western blot. Exogenous human purified SP-A induced stress fiber formation in cultured human myometrial cells via a pathway involving Rho-kinase. Conditioned medium from choriodecidua and amnion explants mimicked the SP-A effect. Treatment of myometrial cells with SP-A-depleted conditioned medium from choriodecidua or amnion explants failed to change the actin dynamic. These data indicate that SP-A released by human fetal membranes is able to exert a paracrine regulation of F-actin filament organization in myometrial cells.
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Affiliation(s)
- Michelle Breuiller-Fouché
- Institut National de la Santé et de la Recherche Médicale (INSERM), U767, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, Paris V, Paris, France.
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19
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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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20
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The effect of acids on dipalmitoyl phosphatidylcholine (DPPC) monolayers and liposomes. Colloids Surf A Physicochem Eng Asp 2009. [DOI: 10.1016/j.colsurfa.2009.04.051] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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21
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Lineage specific evolutionary events on SFTPB gene: Alu recombination-mediated deletion (ARMD), exonization, and alternative splicing events. Gene 2009; 435:29-35. [DOI: 10.1016/j.gene.2009.01.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 01/06/2009] [Accepted: 01/09/2009] [Indexed: 01/30/2023]
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22
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Nakahara H, Lee S, Shibata O. Pulmonary surfactant model systems catch the specific interaction of an amphiphilic peptide with anionic phospholipid. Biophys J 2009; 96:1415-29. [PMID: 19217859 DOI: 10.1016/j.bpj.2008.11.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Accepted: 11/20/2008] [Indexed: 10/21/2022] Open
Abstract
Interfacial behavior was studied in pulmonary surfactant model systems containing an amphiphilic alpha-helical peptide (Hel 13-5), which consists of 13 hydrophobic and five hydrophilic amino acid residues. Fully saturated phospholipids of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) were utilized to understand specific interactions between anionic DPPG and cationic Hel 13-5 for pulmonary functions. Surface pressure (pi)-molecular area (A) and surface potential (DeltaV)-A isotherms of DPPG/Hel 13-5 and DPPC/DPPG (4:1, mol/mol)/Hel 13-5 preparations were measured to obtain basic information on the phase behavior under compression and expansion processes. The interaction leads to a variation in squeeze-out surface pressures against a mole fraction of Hel 13-5, where Hel 13-5 is eliminated from the surface on compression. The phase behavior was visualized by means of Brewster angle microscopy, fluorescence microscopy, and atomic force microscopy. At low surface pressures, the formation of differently ordered domains in size and shape is induced by electrostatic interactions. The domains independently grow upon compression to high surface pressures, especially in the DPPG/Hel 13-5 system. Under the further compression process, protrusion masses are formed in AFM images in the vicinity of squeeze-out pressures. The protrusion masses, which are attributed to the squeezed-out Hel 13-5, grow larger in lateral size with increasing DPPG content in phospholipid compositions. During subsequent expansion up to 35 mN m(-1), the protrusions retain their height and lateral diameter for the DPPG/Hel 13-5 system, whereas the protrusions become smaller for the DPPC/Hel 13-5 and DPPC/DPPG/Hel 13-5 systems due to a reentrance of the ejected Hel 13-5 into the surface. In this work we detected for the first time, to our knowledge, a remarkably large hysteresis loop for cyclic DeltaV-A isotherms of the binary DPPG/Hel 13-5 preparation. This exciting phenomenon suggests that the specific interaction triggers two completely independent processes for Hel 13-5 during repeated compression and expansion: 1), squeezing-out into the subsolution; and 2), and close packing as a monolayer with DPPG at the interface. These characteristic processes are also strongly supported by atomic force microscopy observations. The data presented here provide complementary information on the mechanism and importance of the specific interaction between the phosphatidylglycerol headgroup and the polarized moiety of native surfactant protein B for biophysical functions of pulmonary surfactants.
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Affiliation(s)
- Hiromichi Nakahara
- Department of Biophysical Chemistry, Faculty of Pharmaceutical Sciences, Nagasaki International University, Nagasaki, Japan
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23
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Fenn GB, Taraschi TF, Strayer DS. Targeting Immunoliposomes to Pulmonary Type II and Tracheobroncheal Epithelial Cells. J Liposome Res 2008. [DOI: 10.3109/08982109809039932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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24
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Rugonyi S, Biswas SC, Hall SB. The biophysical function of pulmonary surfactant. Respir Physiol Neurobiol 2008; 163:244-55. [PMID: 18632313 DOI: 10.1016/j.resp.2008.05.018] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2008] [Revised: 05/23/2008] [Accepted: 05/24/2008] [Indexed: 01/12/2023]
Abstract
Pulmonary surfactant lowers surface tension in the lungs. Physiological studies indicate two key aspects of this function: that the surfactant film forms rapidly; and that when compressed by the shrinking alveolar area during exhalation, the film reduces surface tension to very low values. These observations suggest that surfactant vesicles adsorb quickly, and that during compression, the adsorbed film resists the tendency to collapse from the interface to form a 3D bulk phase. Available evidence suggests that adsorption occurs by way of a rate-limiting structure that bridges the gap between the vesicle and the interface, and that the adsorbed film avoids collapse by undergoing a process of solidification. Current models, although incomplete, suggest mechanisms that would partially explain both rapid adsorption and resistance to collapse as well as how different constituents of pulmonary surfactant might affect its behavior.
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Affiliation(s)
- Sandra Rugonyi
- Division of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239-3098, USA.
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Garcia-Verdugo I, Tanfin Z, Dallot E, Leroy MJ, Breuiller-Fouché M. Surfactant protein A signaling pathways in human uterine smooth muscle cells. Biol Reprod 2008; 79:348-55. [PMID: 18463356 DOI: 10.1095/biolreprod.108.068338] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The present study investigated the ability of surfactant associated protein A1 (SFTPA1), a major component of lung surfactant, to bind and serve as a signal in human cultured myometrial cells. By using ligand blot analysis with 125I-SFTPA1, we consistently identified two myometrial SFTPA1 interacting proteins (55 and 200 kDa). We found that the SFTPA1 immunoreactive protein was present in myometrial cells. We also showed by indirect immunofluorescence the nuclear translocation of RELA (also known as NFkappaB p65 subunit) after activation of myometrial cells by SFTPA1. Neutralization of TLR4 did not reverse this effect. Moreover, SFTPA1 rapidly activated mitogen-activated protein kinase 1/3 (MAPK1/3) and protein kinase C zeta (PRKCZ). The prolonged treatment of myometrial cells with SFTPA1 upregulated PTGS2 (COX2) protein levels. We next evaluated whether SFTPA1 affected the actin dynamic. Stimulation of myometrial cells with SFTPA1 markedly enhanced the intensity of the filamentous-actin pool stained with fluorescein isothiocyanate-phalloidin. Inhibition of PRKC or Rho-associated, coiled-coil containing protein kinase 1 (ROCK) reduced the SFTPA1-mediated stress fiber formation. Our data support the hypothesis that human myometrial cells express functional SFTPA1 binding sites and respond to SFTPA1 to initiate activation of signaling events related to human parturition.
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Affiliation(s)
- Ignacio Garcia-Verdugo
- Equipe Signalisation et Régulations Cellulaires, Institut de Biochimie et Biophysique Moléculaire et Cellulaire, CNRS, UMR-8619, Université Paris-Sud, 91400 Orsay, France
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26
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Garcia-Verdugo I, Synguelakis M, Degrouard J, Franco CA, Valot B, Zivy M, Chaby R, Tanfin Z. Interaction of surfactant protein A with the intermediate filaments desmin and vimentin. Biochemistry 2008; 47:5127-38. [PMID: 18407667 DOI: 10.1021/bi800070u] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Surfactant protein A (SP-A), a member of the collectin family that modulates innate immunity, has recently been involved in the physiology of reproduction. Consistent with the activation of ERK-1/2 and COX-2 induced by SP-A in myometrial cells, we reported previously the presence of two major proteins recognized by SP-A in these cells. Here we identify by mass spectrometry one of these SP-A targets as the intermediate filament (IF) desmin. In myometrial preparations derived from desmin-deficient mice, the absence of binding of SP-A to any 50 kDa protein confirmed the identity of this SP-A-binding site as desmin. Our data based on partial chymotrypsin digestion of pure desmin suggested that SP-A recognizes especially its rod domain, which is known to play an important role during the assembly of desmin into filaments. In line with that, electron microscopy experiments showed that SP-A inhibits in vitro the polymerization of desmin filaments. SP-A also recognized in vitro polymerized filaments in a calcium-dependent manner at a physiological ionic strength but not the C1q receptor gC1qR. Furthermore, Texas Red-labeled SP-A colocalized with desmin filaments in myometrial cells. Interestingly, vimentin, the IF characteristic of leukocytes, is one of the major proteins recognized by SP-A in protein extracts of U937 cells after PMA-induced differentiation of this monocytic cell line. Interaction of SP-A with vimentin was further confirmed using recombinant vimentin in solid-phase binding assays. The ability of SP-A to interact with desmin and vimentin, and to prevent polymerization of desmin monomers, shed light on unexpected and wider biological roles of this collectin.
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Affiliation(s)
- Ignacio Garcia-Verdugo
- Institut de Biochimie et Biophysique Moléculaire et Cellulaire, UMR-8619 du CNRS, Université de Paris-Sud, 91400 Orsay, France.
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27
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Bräuer L, Johl M, Börgermann J, Pleyer U, Tsokos M, Paulsen FP. Detection and localization of the hydrophobic surfactant proteins B and C in human tear fluid and the human lacrimal system. Curr Eye Res 2008; 32:931-8. [PMID: 18027169 DOI: 10.1080/02713680701694369] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
PURPOSE To evaluate the expression and presence of the surfactant proteins (SP) B and C in the lacrimal apparatus at the ocular surface and in tear fluid. METHODS Expression of SP-B and SP-C was analyzed by RT-PCR in healthy lacrimal gland, conjunctiva, meibomian gland, accessory lacrimal glands, cornea, and nasolacrimal ducts. The deposition of the hydrophobic proteins SP-B and SP-C was determined by Western blot and immunohistochemistry in healthy tissues, tear fluid, and aqueous humor. RESULTS The presence of both SP-B and SP-C on mRNA and protein level was evidenced in healthy human lacrimal gland, conjunctiva, cornea, and nasolacrimal ducts. Moreover, both proteins were present in tear fluid but were absent in aqueous humor. Immunohistochemical investigations revealed production of both peptides by acinar epithelial cells of the lacrimal gland and additionally by accessory lacrimal glands of the eyelid as well as epithelial cells of the conjunctiva and nasolacrimal ducts. Immunohistochemically, healthy cornea and goblet cells revealed no reactivity. CONCLUSIONS Besides the recently detected surfactant-associated proteins SP-A and SP-D, our results show that SP-B and SP-C are also peptides of the tear film, the ocular surface, and the lacrimal apparatus. Based on the current knowledge of lowering surface tension in alveolar lung cells, a similar effect of SP-B and SP-C may be assumed concerning the tear film.
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Affiliation(s)
- Lars Bräuer
- Department of Anatomy and Cell Biology, Martin Luther University of Halle-Wittenberg, Halle/Saale, Germany.
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García-Verdugo I, Cañadas O, Taneva SG, Keough KMW, Casals C. Surfactant protein A forms extensive lattice-like structures on 1,2-dipalmitoylphosphatidylcholine/rough-lipopolysaccharide-mixed monolayers. Biophys J 2007; 93:3529-40. [PMID: 17693477 PMCID: PMC2072082 DOI: 10.1529/biophysj.107.109793] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Accepted: 07/23/2007] [Indexed: 12/02/2022] Open
Abstract
Due to the inhalation of airborne particles containing bacterial lipopolysaccharide (LPS), these molecules might incorporate into the 1,2-dipalmitoylphosphatidylcholine (DPPC)-rich monolayer and interact with surfactant protein A (SP-A), the major surfactant protein component involved in host defense. In this study, epifluorescence microscopy combined with a surface balance was used to examine the interaction of SP-A with mixed monolayers of DPPC/rough LPS (Re-LPS). Binary monolayers of Re-LPS plus DPPC showed negative deviations from ideal behavior of the mean areas in the films consistent with partial miscibility and attractive interaction between the lipids. This interaction resulted in rearrangement and reduction of the size of DPPC-rich solid domains in DPPC/Re-LPS monolayers. The adsorption of SP-A to these monolayers caused expansion in the lipid molecular areas. SP-A interacted strongly with Re-LPS and promoted the formation of DPPC-rich solid domains. Fluorescently labeled Texas red-SP-A accumulated at the fluid-solid boundary regions and formed networks of interconnected filaments in the fluid phase of DPPC/Re-LPS monolayers in a Ca(2+)-independent manner. These lattice-like structures were also observed when TR-SP-A interacted with lipid A monolayers. These novel results deepen our understanding of the specific interaction of SP-A with the lipid A moiety of bacterial LPS.
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Affiliation(s)
- Ignacio García-Verdugo
- Departamento de Bioquímica y Biología Molecular I and CIBER Enfermedades Respiratorias, Complutense University of Madrid, 28040-Madrid, Spain
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29
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Lhert F, Yan W, Biswas SC, Hall SB. Effects of hydrophobic surfactant proteins on collapse of pulmonary surfactant monolayers. Biophys J 2007; 93:4237-43. [PMID: 17720730 PMCID: PMC2098737 DOI: 10.1529/biophysj.107.111823] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To determine if hydrophobic surfactant proteins affect the stability of pulmonary surfactant monolayers at an air/water interface, the studies reported here compared the kinetics of collapse for the complete set of lipids in calf surfactant with and without the proteins. Monomolecular films spread at the surface of captive bubbles were compressed at 37 degrees C to surface pressures above 46 mN/m, at which collapse first occurred. The rate of area-compression required to maintain a constant surface pressure was measured to directly determine the rate of collapse. For films with and without the proteins, higher surface pressures initially produced faster collapse, but the rates then reached a maximum and decreased to values <0.04 min(-1) above 53 mN/m. The maximum rate for the lipids with the proteins (1.22 +/- 0.28 min(-1)) was almost twice the value for the lipids alone (0.71 +/- 0.15 min(-1)). Because small increments in surface pressure produced large shifts in the rate close to the fastest collapse, compressions at a series of constant speeds also established the threshold rate required to achieve high surface pressure as an indirect indication of the fastest collapse. Both samples produced a sharply defined threshold that occurred at slightly faster compression with the proteins present, supporting the conclusion of the direct measurements that the proteins produce a faster maximum rate of collapse. Our results indicate that at 47-53 mN/m, the hydrophobic surfactant proteins destabilize the compressed monolayers and tend to limit access to the higher surface pressures at which the lipid films become metastable.
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Affiliation(s)
- Florence Lhert
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon 97239, USA
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30
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Lyra PPR, Vaz FAC, Moreira PE, Hoffmann JW, Demello DE, Diniz EMA. Comparison of surfactant protein B polymorphisms of healthy term newborns with preterm newborns having respiratory distress syndrome. Braz J Med Biol Res 2007; 40:779-86. [PMID: 17581675 DOI: 10.1590/s0100-879x2006005000105] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Accepted: 02/27/2007] [Indexed: 11/22/2022] Open
Abstract
Polymorphisms and mutations in the surfactant protein B (SP-B) gene have been associated with the pathogenesis of respiratory distress syndrome (RDS). The objective of the present study was to compare the frequencies of SP-B gene polymorphisms between preterm babies with RDS and healthy term newborns. We studied 50 preterm babies with RDS (inclusion criteria - newborns with RDS and gestational age between 28 and 33 weeks and 6 days), and 100 healthy term newborns. Four SP-B gene polymorphisms were analyzed: A/C at nucleotide -18, C/T at nucleotide 1580, A/G at nucleotide 9306, and G/C at nucleotide 8714, by PCR amplification of genomic DNA and genotyping by cRFLP. The healthy newborns comprised 42 female and 58 male neonates; 39 were white and 61 non-white. The RDS group comprised 21 female and 29 male preterm neonates; 28 were white and 22 non-white. Weight ranged from 640 to 2080 g (mean: 1273 g); mean gestational age was 31 weeks and 2 days (range: 28-33 weeks and 6 days). When white children were analyzed separately, a statistically significant difference in the G/C polymorphism at 8714 was observed between groups (P = 0.028). All other genotype frequencies were similar for both groups when sex and race were analyzed together. Analysis of the SP-B polymorphism G/C at nucleotide 8714 showed that among white neonates the GG genotype was found only in the RDS group at a frequency of 17% and the GC genotype was more frequently found in healthy term newborns. These data demonstrate an association of GG genotype with RDS.
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Affiliation(s)
- P P R Lyra
- Departamento de Pediatria, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
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31
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Lyra PPR, Diniz EMDA. The importance of surfactant on the development of neonatal pulmonary diseases. Clinics (Sao Paulo) 2007; 62:181-90. [PMID: 17505704 DOI: 10.1590/s1807-59322007000200014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2006] [Accepted: 11/28/2006] [Indexed: 11/22/2022] Open
Abstract
Pulmonary surfactant is a substance composed of a lipoprotein complex that is essential to pulmonary function. Pulmonary surfactant proteins play an important role in the structure, function, and metabolism of surfactant; 4 specific surfactant proteins have been identified: surfactant proteins-A, surfactant proteins-B, surfactant proteins-C, and surfactant proteins-D. Clinical, epidemiological, and biochemical evidence suggests that the etiology of respiratory distress syndrome is multifactorial with a significant genetic component. There are reports about polymorphisms and mutations on the surfactant protein genes, especially surfactant proteins-B, that may be associated with respiratory distress syndrome, acute respiratory distress syndrome, and congenital alveolar proteinosis. Individual differences regarding respiratory distress syndrome and acute respiratory distress syndrome as well as patient response to therapy might reflect phenotypic diversity due to genetic variation, in part. The study of the differences between the allelic variants of the surfactant protein genes can contribute to the understanding of individual susceptibility to the development of several pulmonary diseases. The identification of the polymorphisms and mutations that are indeed important for the pathogenesis of the diseases related to surfactant protein dysfunction, leading to the possibility of genotyping individuals at increased risk, constitutes a new research field. In the future, findings in these endeavors may enable more effective genetic counseling as well as the development of prophylactic and therapeutic strategies that would provide a real impact on the management of newborns with respiratory distress syndrome and other pulmonary diseases.
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32
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Garcia-Verdugo I, Leiber D, Robin P, Billon-Denis E, Chaby R, Tanfin Z. Direct interaction of surfactant protein A with myometrial binding sites: signaling and modulation by bacterial lipopolysaccharide. Biol Reprod 2007; 76:681-91. [PMID: 17202387 DOI: 10.1095/biolreprod.106.058131] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Surfactant protein A (SFTPA1), a member of the collagenous lectin (collectin) family, was first described as a major constituent of lung surfactant, but has recently also been found in the female genital tract. Various microorganisms colonize this area and may cause intrauterine infection or trigger preterm labor. We found that SFTPA1 was not produced in the uterus. Instead, it was immunodetected transiently in rat myometrium at the end (Days 19 and 21) of gestation, but not postpartum, and in cultured myometrial cells. Fluorescence microscopy showed that Texas Red-labeled SFTPA1 bound to myometrial cells. This result was confirmed by biochemical approaches. [(125)I]-SFTPA1 bound to two myometrial cell proteins (55 and 210 kDa). This interaction was dependent on the integrity of the collagenlike domain of SFTPA1. SFTPA1 rapidly activated mitogen-activated protein kinase 1/3 (MAPK1/3) in myometrial cells. Bacterial lipopolysaccharide (LPS), an agent known to trigger uterine contractions and preterm birth, also activated MAPK1/3. The prolonged treatment of myometrial cells with LPS or SFTPA1 upregulated PTGS2 (COX2) protein levels. The addition of rough-type LPS to SFTPA1 blocked the interaction of SFTPA1 with its binding sites and the activation of MAPK1/3 and PTGS2 by SFTPA1. Our data provide the first demonstration of a direct effect of SFTPA1 on rat myometrial cells and inhibitory cross talk between SFTPA1 and LPS signals, providing new insight into the mechanisms of normal and preterm parturition.
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Affiliation(s)
- Ignacio Garcia-Verdugo
- Equipe Endotoxines, Institut de Biochimie et Biophysique Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, UMR-8619, Université Paris-Sud, 91400 Orsay, France
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Hickman-Davis JM, Wang Z, Fierro-Perez GA, Chess PR, Page GP, Matalon S, Notter RH. Surfactant dysfunction in SP-A-/- and iNOS-/- mice with mycoplasma infection. Am J Respir Cell Mol Biol 2007; 36:103-13. [PMID: 16917077 PMCID: PMC1899299 DOI: 10.1165/rcmb.2006-0049oc] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Accepted: 07/27/2006] [Indexed: 01/27/2023] Open
Abstract
Surfactant dysfunction was studied in C57BL/6 (B6), B6.SP-A(-/-), and B6.iNOS(-/-) mice with pulmonary mycoplasma infection (10(7) colony-forming units). Cell-free bronchoalveolar lavage (BAL) from uninfected B6.SP-A(-/-) versus B6 mice had a reduced content of very large aggregates (VLA) and an increase in intermediate large aggregates (ILA), with no difference in total large aggregates (LA = VLA + ILA). However, LA from uninfected B6.SP-A(-/-) versus B6 mice contained less protein and were more sensitive to inhibition by serum albumin and lysophosphatidylcholine in pulsating bubble studies in vitro. Infection with Mycoplasma pulmonis caused significant lung injury and surfactant abnormalities in B6.SP-A(-/-), B6.iNOS(-/-), and B6 mice at 24, 48, 72 h after infection compared with uninfected mice of the same strain. Analyses of time-pooled data indicated that mycoplasma-infected B6.SP-A(-/-) and B6.iNOS(-/-) mice had significantly lower levels of LA and higher protein/phospholipid ratios in BAL compared with infected B6 mice. Infected B6.iNOS(-/-) versus B6 mice also had increased minimum surface tensions on the pulsating bubble and decreased levels of surfactant protein (SP)-B in BAL. These results indicate that pulmonary mycoplasma infection in vivo causes lung injury and surfactant abnormalities that are dependent in part on iNOS and SP-A. In addition, SP-A deficiency modifies surfactant aggregate content and lowers the inhibition resistance of LA surfactant in vitro compared with congenic normal mice.
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Affiliation(s)
- Judy M Hickman-Davis
- Department of Pediatrics, University of Rochester School of Medicine, Rochester, NY 14642, USA
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Sáenz A, Cañadas O, Bagatolli LA, Sánchez-Barbero F, Johnson ME, Casals C. Effect of surfactant protein A on the physical properties and surface activity of KL4-surfactant. Biophys J 2006; 92:482-92. [PMID: 17056727 PMCID: PMC1751418 DOI: 10.1529/biophysj.106.090217] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SP-A, the major protein component of pulmonary surfactant, is absent in exogenous surfactants currently used in clinical practice. However, it is thought that therapeutic properties of natural surfactants improve after enrichment with SP-A. The objective of this study was to determine SP-A effects on physical properties and surface activity of a new synthetic lung surfactant based on a cationic and hydrophobic 21-residue peptide KLLLLKLLLLKLLLLKLLLLK, KL(4). We have analyzed the interaction of SP-A with liposomes consisting of DPPC/POPG/PA (28:9:5.6, w/w/w) with and without 0.57 mol % KL(4) peptide. We found that SP-A had a concentration-dependent effect on the surface activity of KL(4)-DPPC/POPG/PA membranes but not on that of an animal-derived LES. The surface activity of KL(4)-surfactant significantly improved after enrichment with 2.5-5 wt % SP-A. However, it worsened at SP-A concentrations > or =10 wt %. This was due to the fluidizing effect of supraphysiological SP-A concentrations on KL(4)-DPPC/POPG/PA membranes as determined by fluorescence anisotropy measurements, calorimetric studies, and confocal fluorescence microscopy of GUVs. High SP-A concentrations caused disappearance of the solid/fluid phase coexistence of KL(4)-surfactant, suggesting that phase coexistence might be important for the surface adsorption process.
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Affiliation(s)
- Alejandra Sáenz
- Department of Biochemistry and Molecular Biology I, Complutense University of Madrid, Madrid, Spain
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Mazela J, Merritt TA, Gadzinowski J, Sinha S. Evolution of pulmonary surfactants for the treatment of neonatal respiratory distress syndrome and paediatric lung diseases. Acta Paediatr 2006; 95:1036-48. [PMID: 16938747 DOI: 10.1080/08035250600615168] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
UNLABELLED This review documents the evolution of surfactant therapy, beginning with observations of surfactant deficiency in respiratory distress syndrome, the basis of exogenous surfactant treatment and the development of surfactant-containing novel peptides patterned after SP-B. We critically analyse the molecular interactions of surfactant proteins and phospholipids contributing to surfactant function. CONCLUSION Peptide-containing surfactant provides clinical efficacy in the treatment of respiratory distress syndrome and offers promise for treating other lung diseases in infancy.
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Affiliation(s)
- Jan Mazela
- Department of Neonatology, Poznan University of Medical Sciences, Poznan, and Polish Mother's Memorial Hospital Research Institute, Lodz, Poland
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36
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Parmigiani S, Solari E, Bevilacqua G. Current concepts on the pulmonary surfactant in infants. J Matern Fetal Neonatal Med 2006; 18:369-80. [PMID: 16390802 DOI: 10.1080/14767050500244552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Surfactant has been a main topic of neonatology in the last 20 years. Many studies have been conducted since the discovery of its role in the pathogenesis of respiratory distress syndrome and the knowledge on its composition and metabolism has become complex. In this article we review the current concepts of its metabolism, ways of acting, properties of its proteins and activities other than the ability of reducing surface tension within the lung as a basis to understand the development of disease in case of its deficiency.
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Affiliation(s)
- S Parmigiani
- Department of Gynecologic, Obstetric and Neonatologic Sciences, Section of Child Health and Neonatology, University of Parma, Parma, Italy.
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Wüstneck R, Perez-Gil J, Wüstneck N, Cruz A, Fainerman VB, Pison U. Interfacial properties of pulmonary surfactant layers. Adv Colloid Interface Sci 2005; 117:33-58. [PMID: 16120435 DOI: 10.1016/j.cis.2005.05.001] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Revised: 02/16/2005] [Accepted: 05/20/2005] [Indexed: 11/25/2022]
Abstract
The composition of the pulmonary surfactant and the border conditions of normal human breathing are relevant to characterize the interfacial behavior of pulmonary layers. Based on experimental data methods are reviewed to investigate interfacial properties of artificial pulmonary layers and to explain the behavior and interfacial structures of the main components during compression and expansion of the layers observed by epifluorescence and scanning force microscopy. Terms like over-compression, collapse, and formation of the surfactant reservoir are discussed. Consequences for the viscoelastic surface rheological behavior of such layers are elucidated by surface pressure relaxation and harmonic oscillation experiments. Based on a generalized Volmer isotherm the interfacial phase transition is discussed for the hydrophobic surfactant proteins, SP-B and SP-C, as well as for the mixtures of dipalmitoylphosphatidylcholine (DPPC) with these proteins. The behavior of the layers depends on both the oligomerisation state and the secondary structure of the hydrophobic surfactant proteins, which are controlled by the preparation of the proteins. An example for the surface properties of bronchoalveolar porcine lung washings of uninjured, injured, and Curosurf treated lavage is discussed in the light of surface behavior. An outlook summarizes the present knowledge and the main future development in this field of surface science.
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Affiliation(s)
- R Wüstneck
- Charité, Campus Virchow-Klinikum, Universitätsmedizin Berlin, Klinik für Anästhesiologie und operative Intensivmedizin, Spandauer Damm 130, 14050 Berlin, Germany.
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Gorrini M, Lupi A, Iadarola P, Santos CD, Rognoni P, Dalzoppo D, Carrabino N, Pozzi E, Baritussio A, Luisetti M. SP-A binds alpha1-antitrypsin in vitro and reduces the association rate constant for neutrophil elastase. Respir Res 2005; 6:146. [PMID: 16351724 PMCID: PMC1343571 DOI: 10.1186/1465-9921-6-146] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2005] [Accepted: 12/13/2005] [Indexed: 11/10/2022] Open
Abstract
Background α1-antitrypsin and surfactant protein-A (SP-A) are major lung defense proteins. With the hypothesis that SP-A could bind α1-antitrypsin, we designed a series of in vitro experiments aimed at investigating the nature and consequences of such an interaction. Methods and results At an α1-antitrypsin:SP-A molar ratio of 1:1, the interaction resulted in a calcium-dependent decrease of 84.6% in the association rate constant of α1-antitrypsin for neutrophil elastase. The findings were similar when SP-A was coupled with the Z variant of α1-antitrypsin. The carbohydrate recognition domain of SP-A appeared to be a major determinant of the interaction, by recognizing α1-antitrypsin carbohydrate chains. However, binding of SP-A carbohydrate chains to the α1-antitrypsin amino acid backbone and interaction between carbohydrates of both proteins are also possible. Gel filtration chromatography and turnover per inactivation experiments indicated that one part of SP-A binds several molar parts of α1-antitrypsin. Conclusion We conclude that the binding of SP-A to α1-antitrypsin results in a decrease of the inhibition of neutrophil elastase. This interaction could have potential implications in the physiologic regulation of α1-antitrypsin activity, in the pathogenesis of pulmonary emphysema, and in the defense against infectious agents.
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Affiliation(s)
- Marina Gorrini
- Laboratorio di Biochimica e Genetica, Clinica di Malattie dell'Apparato Respiratorio, IRCCS Policlinico San Matteo, Università di Pavia, Pavia, Italy
- Clinica di Malattie dell'Apparato Respiratorio, IRCCS Policlinico San Matteo, Università di Pavia, Pavia, Italy
| | - Anna Lupi
- Dipartimento di Biochimica "A. Castellani", Università di Pavia, Pavia, Italy
| | - Paolo Iadarola
- Dipartimento di Biochimica "A. Castellani", Università di Pavia, Pavia, Italy
| | - Conceição Dos Santos
- Laboratorio Sperimentale di Ricerca Trapiantologia, Clinica Pediatrica, IRCCS Policlinico San Matteo, Università di Pavia, Pavia, Italy
| | - Paola Rognoni
- Dipartimento di Biochimica "A. Castellani", Università di Pavia, Pavia, Italy
| | - Daniele Dalzoppo
- Istituto di Chimica Farmaceutica, Università di Padova, Padova, Italy
| | - Natalia Carrabino
- Clinica di Malattie dell'Apparato Respiratorio, IRCCS Policlinico San Matteo, Università di Pavia, Pavia, Italy
| | - Ernesto Pozzi
- Clinica di Malattie dell'Apparato Respiratorio, IRCCS Policlinico San Matteo, Università di Pavia, Pavia, Italy
| | - Aldo Baritussio
- Dipartimento di Scienze Mediche e Chirurgiche, Clinica Medica I, Università di Padova, Padova, Italy
| | - Maurizio Luisetti
- Laboratorio di Biochimica e Genetica, Clinica di Malattie dell'Apparato Respiratorio, IRCCS Policlinico San Matteo, Università di Pavia, Pavia, Italy
- Clinica di Malattie dell'Apparato Respiratorio, IRCCS Policlinico San Matteo, Università di Pavia, Pavia, Italy
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Réty S, Salamitou S, Garcia-Verdugo I, Hulmes DJS, Le Hégarat F, Chaby R, Lewit-Bentley A. The crystal structure of the Bacillus anthracis spore surface protein BclA shows remarkable similarity to mammalian proteins. J Biol Chem 2005; 280:43073-8. [PMID: 16249180 DOI: 10.1074/jbc.m510087200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The lethal disease anthrax is propagated by spores of Bacillus anthracis, which can penetrate into the mammalian host by inhalation, causing a rapid progression of the disease and a mostly fatal outcome. We have solved the three-dimensional structure of the major surface protein BclA on B. anthracis spores. Surprisingly, the structure resembles C1q, the first component of complement, despite there being no sequence homology. Although most assays for C1q-like activity, including binding to C1q receptors, suggest that BclA does not mimic C1q, we show that BclA, as well as C1q, interacts with components of the lung alveolar surfactant layer. Thus, to better recognize and invade its hosts, this pathogenic soil bacterium may have evolved a surface protein whose structure is strikingly close to a mammalian protein.
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Affiliation(s)
- Stéphane Réty
- Laboratoire de Biotechnologies et Pharmacologie Génétique Appliquées, CNRS, Unité Mixte de Recherche 8113, Ecole Normale Supérieure de Cachan, 61 Avenue du Président Wilson, 94235 Cachan, France
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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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Surfactant metabolism: factors affecting lipid uptake in vivo and in vitro. ANAESTHESIA, PAIN, INTENSIVE CARE AND EMERGENCY MEDICINE — A.P.I.C.E. 2005. [PMCID: PMC7122009 DOI: 10.1007/88-470-0351-2_25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Sánchez-Barbero F, Strassner J, García-Cañero R, Steinhilber W, Casals C. Role of the degree of oligomerization in the structure and function of human surfactant protein A. J Biol Chem 2004; 280:7659-70. [PMID: 15615713 DOI: 10.1074/jbc.m410266200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The role of the degree of oligomerization in the structure and function of human surfactant protein A (SP-A) was investigated using a human SP-A1 mutant (SP-A1(DeltaAVC,C6S)), expressed in mammalian cells, resulting from site-directed substitution of serine for Cys(6) and substitution of a functional signal peptide for the cysteine-containing SP-A signal sequence. This Cys(6) mutant lacked the NH(2)-terminal Ala(-3)-Val(-2)-Cys(-1) (DeltaAVC) extension present in some SP-A1 isoforms. SP-A1(DeltaAVC,C6S) was assembled exclusively as trimers as detected by electron microscopy and size exclusion chromatography. Trimeric SP-A1(DeltaAVC,C6S) was compared with supratrimeric SP-A1, which is structurally and functionally comparable to the octadecameric protein isolated from human lung lavages. SP-A1(DeltaAVC,C6S) showed reduced thermal stability of the collagen domain, studied by circular dichroism, and increased susceptibility to trypsin degradation. The T(m) was 32.7 degrees C for SP-A1(DeltaAVC,C6S) and 44.5 degrees C for SP-A1. Although SP-A1(DeltaAVC,C6S) was capable of binding to calcium, rough lipopolysaccharide, and phospholipid vesicles, this mutant was unable to induce rough lipopolysaccharide and phospholipid vesicle aggregation, to enhance the interfacial adsorption of SP-B/SP-C-surfactant membranes, and to undergo self-association in the presence of Ca(2+). On the other hand, the lack of supratrimeric assembly hardly affected the ability of SP-A1(DeltaAVC,C6S) to inhibit the production of tumor necrosis factor-alpha by macrophage-like U937 cells stimulated with either smooth or rough lipopolysaccharide. We conclude that supratrimeric assembly of human SP-A is essential for collagen triple helix stability at physiological temperatures, protection against proteases, protein self-association, and SP-A-induced ligand aggregation. The supratrimeric assembly is not essential for the binding of SP-A to ligands and anti-inflammatory effects of SP-A.
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Affiliation(s)
- Fernando Sánchez-Barbero
- Department of Biochemistry and Molecular Biology I, Complutense University of Madrid, 28040 Madrid, Spain
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43
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Poelma DLH, Zimmermann LJ, van Cappellen WA, Haitsma JJ, Lachmann B, van Iwaarden JF. Distinct effects of SP-B and SP-C on the uptake of surfactant-like liposomes by alveolar cells in vivo and in vitro. Am J Physiol Lung Cell Mol Physiol 2004; 287:L1056-65. [PMID: 15257983 DOI: 10.1152/ajplung.00054.2004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effects of surfactant protein B (SP-B) and SP-C on the uptake of surfactant-like liposomes by alveolar type II cells and alveolar macrophages were studied both in vivo and in vitro. In vivo, mechanically ventilated rats were intratracheally instilled with fluorescently labeled liposomes that had SP-B and/or SP-C incorporated in different concentrations. Consequently, the alveolar cells were isolated, and cell-associated fluorescence was determined using flow cytometry. The results show that the incorporation of SP-B does not influence the uptake, and it also does not in the presence of essential cofactors. The inclusion of SP-C in the liposomes enhanced the alveolar type II cells at a SP-C to lipid ratio of 2:100. If divalent cations (calcium and magnesium) were present at physiological concentrations in the liposome suspension, uptake of liposomes by alveolar macrophages was also enhanced. In vitro, the incorporation of SP-B affected uptake only at a protein-to-lipid ratio of 8:100, whereas the inclusion of SP-C in the liposomes leads to an increased uptake at a protein-to-lipid ratio of 1:100. From these results, it can be concluded that SP-B is unlikely to affect uptake of surfactant, whereas SP-C in combination with divalent cations and other solutes are capable of increasing the uptake.
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Affiliation(s)
- D L H Poelma
- Department of Anesthesiology, Erasmus Medical Center, Rotterdam, The Netherlands
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Abstract
The hydrophobic proteins SP-B and SP-C promote rapid adsorption of pulmonary surfactant to an air/water interface by an unknown mechanism. We tested the hypothesis that these proteins accelerate adsorption by disrupting the structure of the lipid bilayer, either by a generalized increase in fluidity or by a focal induction of interfacial boundaries within the bilayer. We used fluorescence recovery after photobleaching to measure diffusion of nitrobenzoxadiazolyl-dimyristoyl-phosphatidylethanolamine between 11 and 54 degrees C in multilayers containing the complete set of lipids and proteins in calf lung surfactant extract (CLSE), or the complete set of neutral and phospholipids without the proteins. Above 35 degrees C, Arrhenius plots of diffusion were parallel for CLSE and neutral and phospholipids, but shifted to lower values for CLSE, suggesting that the proteins rigidify the lipid bilayer rather than producing the proposed increase in membrane fluidity. The slopes of the Arrhenius plots for CLSE were steeper below 35 degrees C, suggesting that the proteins induce phase separation at that temperature. The mobile fraction fell below 27 degrees C, consistent with a percolation threshold of coexisting gel and liquid-crystal phases. The induction of lateral phase separation in CLSE, however, does not correlate with apparent changes in adsorption kinetics at this temperature. Our results suggest that SP-B and SP-C accelerate adsorption through a mechanism other than the disruption of surfactant bilayers, possibly by stabilizing a high-energy, highly curved adsorption intermediate.
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Affiliation(s)
- Vincent Schram
- Department of Biochemistry, Oregon Health & Science University, Portland, Oregon 97239-3098, USA
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45
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Abstract
The hydrophobic proteins SP-B and SP-C promote rapid adsorption of pulmonary surfactant to an air/water interface by an unknown mechanism. We tested the hypothesis that these proteins accelerate adsorption by disrupting the structure of the lipid bilayer, either by a generalized increase in fluidity or by a focal induction of interfacial boundaries within the bilayer. We used fluorescence recovery after photobleaching to measure diffusion of nitrobenzoxadiazolyl-dimyristoyl-phosphatidylethanolamine between 11 and 54 degrees C in multilayers containing the complete set of lipids and proteins in calf lung surfactant extract (CLSE), or the complete set of neutral and phospholipids without the proteins. Above 35 degrees C, Arrhenius plots of diffusion were parallel for CLSE and neutral and phospholipids, but shifted to lower values for CLSE, suggesting that the proteins rigidify the lipid bilayer rather than producing the proposed increase in membrane fluidity. The slopes of the Arrhenius plots for CLSE were steeper below 35 degrees C, suggesting that the proteins induce phase separation at that temperature. The mobile fraction fell below 27 degrees C, consistent with a percolation threshold of coexisting gel and liquid-crystal phases. The induction of lateral phase separation in CLSE, however, does not correlate with apparent changes in adsorption kinetics at this temperature. Our results suggest that SP-B and SP-C accelerate adsorption through a mechanism other than the disruption of surfactant bilayers, possibly by stabilizing a high-energy, highly curved adsorption intermediate.
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46
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Brasch F, Johnen G, Winn-Brasch A, Guttentag SH, Schmiedl A, Kapp N, Suzuki Y, Müller KM, Richter J, Hawgood S, Ochs M. Surfactant protein B in type II pneumocytes and intra-alveolar surfactant forms of human lungs. Am J Respir Cell Mol Biol 2004; 30:449-58. [PMID: 12972403 DOI: 10.1165/rcmb.2003-0262oc] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Surfactant protein B (SP-B) is synthesized by type II pneumocytes as a proprotein (proSP-B) that is proteolytically processed to an 8-kD protein. In human type II pneumocytes, we identified not only proSP-B, processing intermediates of proSP-B, and mature SP-B, but also fragments of the N-terminal propeptide. By means of immunoelectron microscopy, proSP-B and processing intermediates were localized in the endoplasmic reticulum, Golgi vesicles, and few multivesicular bodies in type II pneumocytes in human lungs. A colocalization of fragments of the N-terminal propeptide and mature SP-B was found in multivesicular, composite, and some lamellar bodies. Mature SP-B was localized over the projection core of lamellar bodies and core-like structures in tubular myelin figures. In line with immunoelectron microscopy and Western blot analysis of human type II pneumocytes, a fragment of the N-terminal propeptide was also detected in isolated rat lamellar bodies. In conclusion, our data indicate that the processing of proSP-B occurs between the Golgi complex and multivesicular bodies and provide evidence that a fragment of the N-terminal propeptide and mature SP-B are transported together to the lamellar bodies. In human lungs, mature SP-B is involved in the structural organization of lamellar bodies and tubular myelin by the formation of core particles.
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Affiliation(s)
- Frank Brasch
- Department of Anatomy, University of Göttingen, Göttingen, Germany.
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Scott JE. The pulmonary surfactant: impact of tobacco smoke and related compounds on surfactant and lung development. Tob Induc Dis 2004; 2:3-25. [PMID: 19570267 PMCID: PMC2671518 DOI: 10.1186/1617-9625-2-1-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Cigarette smoking, one of the most pervasive habits in society, presents many well established health risks. While lung cancer is probably the most common and well documented disease associated with tobacco exposure, it is becoming clear from recent research that many other diseases are causally related to smoking. Whether from direct smoking or inhaling environmental tobacco smoke (ETS), termed secondhand smoke, the cells of the respiratory tissues and the lining pulmonary surfactant are the first body tissues to be directly exposed to the many thousands of toxic chemicals in tobacco. Considering the vast surface area of the lung and the extreme attenuation of the blood-air barrier, it is not surprising that this organ is the primary route for exposure, not just to smoke but to most environmental contaminants. Recent research has shown that the pulmonary surfactant, a complex mixture of phospholipids and proteins, is the first site of defense against particulates or gas components of smoke. However, it is not clear what effect smoke has on the surfactant. Most studies have demonstrated that smoking reduces bronchoalveolar lavage phospholipid levels. Some components of smoke also appear to have a direct detergent-like effect on the surfactant while others appear to alter cycling or secretion. Ultimately these effects are reflected in changes in the dynamics of the surfactant system and, clinically in changes in lung mechanics. Similarly, exposure of the developing fetal lung through maternal smoking results in postnatal alterations in lung mechanics and higher incidents of wheezing and coughing. Direct exposure of developing lung to nicotine induces changes suggestive of fetal stress. Furthermore, identification of nicotinic receptors in fetal lung airways and corresponding increases in airway connective tissue support a possible involvement of nicotine in postnatal asthma development. Finally, at the level of the alveoli of the lung, colocalization of nicotinic receptors and surfactant-specific protein in alveolar cells is suggestive of a role in surfactant metabolism. Further research is needed to determine the mechanistic effects of smoke and its components on surfactant function and, importantly, the effects of smoke components on the developing pulmonary system.
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Affiliation(s)
- J Elliott Scott
- Lung Development Section, Biology of Breathing Group, Manitoba Institute of Child Health & Departments of Oral Biology and Anatomy, Faculties of Dentistry and Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
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Abstract
Among the families of peptidomimetic foldamers under development as novel biomaterials and therapeutics, poly-N-substituted glycines (peptoids) with alpha-chiral side chains are of particular interest for their ability to adopt stable, helical secondary structure in organic and aqueous solution. Here, we show that a peptoid 22-mer with a biomimetic sequence of side chains and an amphipathic, helical secondary structure acts as an excellent mimic of surfactant protein C (SP-C), a small protein that plays an important role in surfactant replacement therapy for the treatment of neonatal respiratory distress syndrome. When integrated into a lipid film, the helical peptoid SP mimic captures the essential surface-active behaviors of the natural protein. This work provides an example of how an abiological oligomer that closely mimics both the hydrophobic/polar sequence patterning and the fold of a natural protein can also mimic its biophysical function.
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Affiliation(s)
- Cindy W Wu
- Department of Chemical Engineering, Northwestern University, 2145 Sheridan Road, Room E136, Evanston, IL 60208, USA
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García-Verdugo I, Sánchez-Barbero F, Bosch FU, Steinhilber W, Casals C. Effect of hydroxylation and N187-linked glycosylation on molecular and functional properties of recombinant human surfactant protein A. Biochemistry 2003; 42:9532-42. [PMID: 12911295 DOI: 10.1021/bi0347196] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The objective of this study was to determine the effects of proline hydroxylation in the collagen-like domain and Asn(187)-linked glycosylation in the globular domain on the molecular and functional properties of human surfactant protein A1 (SP-A1). To address this issue, SP-A1 was in vitro expressed in insect and mammalian cells. Insect cells lack prolyl 4-hydroxylase activity. A glycosylation-deficient mutant SP-A1 was expressed in insect cells. In this report we present evidence that hydroxylation increased the T(m) of the collagen-like domain by 9 degrees C. Proline hydroxylation affected both the arrangement of disulfide bonding and the extent of oligomerization but did not affect conformational changes in the globular domain identified by intrinsic fluorescence. Both self-association and lipid-related functions of SP-A were clearly correlated with the thermal stability of the collagen domain and the degree of oligomerization. Structural properties and lipid-related characteristics of SP-A1 expressed in mammalian cells but not in insect cells were close to that of natural human SP-A. On the other hand, the lack of glycosylation did not affect either collagen domain stability or conformational changes induced by calcium in the globular domain. However, the lack of glycosylation favored nonspecific thermally induced aggregation of the protein.
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Affiliation(s)
- I García-Verdugo
- Department of Biochemistry and Molecular Biology I, Complutense University of Madrid, 28040-Madrid, Spain
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Abstract
BACKGROUND All organisms have developed an internal timing system capable of reacting to and anticipating environmental stimuli with a program of appropriately timed metabolic, physiologic and behavioral events. The alveolar epithelial type II cell of the mammalian lung synthesizes, stores, and secretes a lipoprotein pulmonary surfactant, which functions to stabilize alveoli at low lung volumes. METHODS The authors investigated the diurnal variation of surfactant protein A, B and C mRNA accumulation. The diunal variation on gene expression of surfactant protein A, B and C was analysed using filter hybridization at 9 a.m., 4 p.m. and 11 p.m. Lung SP-A protein content was determined by double sandwich ELISA assay using a polyclonal antiserum raised in rabbits against purified rat SP-A. RESULTS 1. The accumulation of SP-A mRNA at 4 p.m. was significantly decreased by 23.5% compared to the value at 9 a.m. (p < 0.05). 2. The accumulation of SP-B mRNA at 4 p.m. and 11 p.m. was decreased by 15.1% and 5.7%, respectively, compared to the value at 9 a.m. (p = 0.07, p = 0.69). 3. The accumulation of SP-C mRNA at 4 p.m. and 11 p.m. was decreased by 6.8% and 7.7%, respectively, compared to the value at 9 a.m. (p = 0.38, p = 0.57). 4. Total lung SP-A content at 4 p.m. and 11 p.m. was increased by 5.3% and 15.9%, respectively, compared to the value at 9 a.m. (p = 0.64, p = 0.47). CONCLUSION These findings represent the diurnal variation of surfactant proteins mRNA expression in vivo. These results indicated that the diurnal variation of significant gene expression is observed in hydrophilic surfactant protein rather than in hydrophobic surfactant proteins.
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Affiliation(s)
| | | | | | | | - Sung Soo Park
- Correspondence to : Sung Soo Park, M.D., Department of Medicine, Hanyang University College of Medicine, 17 Haengdang-dong, Sungdong-gu, Seoul 133-792, Korea E-mail :
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