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Abstract
Pulmonary surfactant is a critical component of lung function in healthy individuals. It functions in part by lowering surface tension in the alveoli, thereby allowing for breathing with minimal effort. The prevailing thinking is that low surface tension is attained by a compression-driven squeeze-out of unsaturated phospholipids during exhalation, forming a film enriched in saturated phospholipids that achieves surface tensions close to zero. A thorough review of past and recent literature suggests that the compression-driven squeeze-out mechanism may be erroneous. Here, we posit that a surfactant film enriched in saturated lipids is formed shortly after birth by an adsorption-driven sorting process and that its composition does not change during normal breathing. We provide biophysical evidence for the rapid formation of an enriched film at high surfactant concentrations, facilitated by adsorption structures containing hydrophobic surfactant proteins. We examine biophysical evidence for and against the compression-driven squeeze-out mechanism and propose a new model for surfactant function. The proposed model is tested against existing physiological and pathophysiological evidence in neonatal and adult lungs, leading to ideas for biophysical research, that should be addressed to establish the physiological relevance of this new perspective on the function of the mighty thin film that surfactant provides.
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Affiliation(s)
- Fred Possmayer
- Department of Biochemistry, Western University, London, Ontario N6A 3K7, Canada
- Department of Obstetrics/Gynaecology, Western University, London, Ontario N6A 3K7, Canada
| | - Yi Y Zuo
- Department of Mechanical Engineering, University of Hawaii at Manon, Honolulu, Hawaii 96822, United States
- Department of Pediatrics, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96826, United States
| | - Ruud A W Veldhuizen
- Department of Physiology & Pharmacology, Western University, London, Ontario N6A 5C1, Canada
- Department of Medicine, Western University, London, Ontario N6A 3K7, Canada
- Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
| | - Nils O Petersen
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
- Department of Chemistry, Western University, London, Ontario N6A 5B7, Canada
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2
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Sengupta A, Roldan N, Kiener M, Froment L, Raggi G, Imler T, de Maddalena L, Rapet A, May T, Carius P, Schneider-Daum N, Lehr CM, Kruithof-de Julio M, Geiser T, Marti TM, Stucki JD, Hobi N, Guenat OT. A New Immortalized Human Alveolar Epithelial Cell Model to Study Lung Injury and Toxicity on a Breathing Lung-On-Chip System. FRONTIERS IN TOXICOLOGY 2022; 4:840606. [PMID: 35832493 PMCID: PMC9272139 DOI: 10.3389/ftox.2022.840606] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 05/09/2022] [Indexed: 12/13/2022] Open
Abstract
The evaluation of inhalation toxicity, drug safety and efficacy assessment, as well as the investigation of complex disease pathomechanisms, are increasingly relying on in vitro lung models. This is due to the progressive shift towards human-based systems for more predictive and translational research. While several cellular models are currently available for the upper airways, modelling the distal alveolar region poses several constraints that make the standardization of reliable alveolar in vitro models relatively difficult. In this work, we present a new and reproducible alveolar in vitro model, that combines a human derived immortalized alveolar epithelial cell line (AXiAEC) and organ-on-chip technology mimicking the lung alveolar biophysical environment (AXlung-on-chip). The latter mimics key features of the in vivo alveolar milieu: breathing-like 3D cyclic stretch (10% linear strain, 0.2 Hz frequency) and an ultrathin, porous and elastic membrane. AXiAECs cultured on-chip were characterized for their alveolar epithelial cell markers by gene and protein expression. Cell barrier properties were examined by TER (Transbarrier Electrical Resistance) measurement and tight junction formation. To establish a physiological model for the distal lung, AXiAECs were cultured for long-term at air-liquid interface (ALI) on-chip. To this end, different stages of alveolar damage including inflammation (via exposure to bacterial lipopolysaccharide) and the response to a profibrotic mediator (via exposure to Transforming growth factor β1) were analyzed. In addition, the expression of relevant host cell factors involved in SARS-CoV-2 infection was investigated to evaluate its potential application for COVID-19 studies. This study shows that AXiAECs cultured on the AXlung-on-chip exhibit an enhanced in vivo-like alveolar character which is reflected into: 1) Alveolar type 1 (AT1) and 2 (AT2) cell specific phenotypes, 2) tight barrier formation (with TER above 1,000 Ω cm2) and 3) reproducible long-term preservation of alveolar characteristics in nearly physiological conditions (co-culture, breathing, ALI). To the best of our knowledge, this is the first time that a primary derived alveolar epithelial cell line on-chip representing both AT1 and AT2 characteristics is reported. This distal lung model thereby represents a valuable in vitro tool to study inhalation toxicity, test safety and efficacy of drug compounds and characterization of xenobiotics.
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Affiliation(s)
- Arunima Sengupta
- Organs-on-Chip Technologies, ARTORG Center for Biomedical Engineering, University of Bern, Bern, Switzerland
| | - Nuria Roldan
- Alveolix AG, Swiss Organs-on-Chip Innovation, Bern, Switzerland
| | - Mirjam Kiener
- Department of Pulmonary Medicine, Inselspital, Bern University Hospital, Bern, Switzerland.,Department for BioMedical Research DBMR, Urology Research Laboratory, University of Bern, Bern, Switzerland
| | - Laurène Froment
- Alveolix AG, Swiss Organs-on-Chip Innovation, Bern, Switzerland
| | - Giulia Raggi
- Alveolix AG, Swiss Organs-on-Chip Innovation, Bern, Switzerland
| | - Theo Imler
- Alveolix AG, Swiss Organs-on-Chip Innovation, Bern, Switzerland
| | | | - Aude Rapet
- Alveolix AG, Swiss Organs-on-Chip Innovation, Bern, Switzerland
| | | | - Patrick Carius
- Department of Drug Delivery (DDEL), Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany.,Department of Pharmacy, Biopharmaceutics and Pharmaceutical Technology, Saarland University, Saarbrücken, Germany
| | - Nicole Schneider-Daum
- Department of Drug Delivery (DDEL), Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany.,Department of Pharmacy, Biopharmaceutics and Pharmaceutical Technology, Saarland University, Saarbrücken, Germany
| | - Claus-Michael Lehr
- Department of Drug Delivery (DDEL), Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany.,Department of Pharmacy, Biopharmaceutics and Pharmaceutical Technology, Saarland University, Saarbrücken, Germany
| | - Marianna Kruithof-de Julio
- Department for BioMedical Research DBMR, Urology Research Laboratory, University of Bern, Bern, Switzerland
| | - Thomas Geiser
- Department of Pulmonary Medicine, Inselspital, Bern University Hospital, Bern, Switzerland
| | - Thomas Michael Marti
- Department of General Thoracic Surgery, Inselspital, Bern University Hospital, Bern, Switzerland
| | - Janick D Stucki
- Alveolix AG, Swiss Organs-on-Chip Innovation, Bern, Switzerland
| | - Nina Hobi
- Alveolix AG, Swiss Organs-on-Chip Innovation, Bern, Switzerland
| | - Olivier T Guenat
- Organs-on-Chip Technologies, ARTORG Center for Biomedical Engineering, University of Bern, Bern, Switzerland.,Department of Pulmonary Medicine, Inselspital, Bern University Hospital, Bern, Switzerland.,Department of General Thoracic Surgery, Inselspital, Bern University Hospital, Bern, Switzerland
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3
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Delestrain C, Aissat A, Simon S, Tarze A, Duprat E, Nattes E, Costes B, Delattre V, Finet S, Fanen P, Epaud R. Methylprednisolone pulse treatment improves ProSP-C trafficking in twins with SFTPC mutation: An isoform story? Br J Clin Pharmacol 2021; 87:2361-2373. [PMID: 33179299 DOI: 10.1111/bcp.14645] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/29/2020] [Accepted: 10/20/2020] [Indexed: 11/28/2022] Open
Abstract
Mutations in the gene encoding surfactant protein C (SP-C) cause interstitial lung disease (ILD), and glucocorticosteroid (GC) treatment is the most recognized therapy in children. We aimed to decipher the mechanisms behind successful GC treatment in twins carrying a BRICHOS c.566G > A (p.Cys189Tyr) mutation in the SP-C gene (SFTPC). METHODS: The twins underwent bronchoscopy before and after GC treatment and immunoblotting analysis of SP-C proprotein (proSP-C) and SP-C mature in bronchoalveolar fluid (BALF). Total RNA was extracted and analysed using quantitative real-time PCR assays. In A549 cells, the processing of mutated protein C189Y was studied by immunofluorescence and immunoblotting after heterologous expression of eukaryotic vectors containing wild type or C189Y mutant cDNA. RESULTS: Before treatment, BALF analysis identified an alteration of the proSP-C maturation process. Functional study of C189Y mutation in alveolar A549 cells showed that pro-SP-CC189Y was retained within the endoplasmic reticulum together with ABCA3. After 5 months of GC treatment with clinical benefit, the BALF analysis showed an improvement of proSP-C processing. SFTPC mRNA analysis in twins revealed a decrease in the expression of total SFTPC mRNA and a change in its splicing, leading to the expression of a second shorter proSP-C isoform. In A549 cells, the processing and the stability of this shorter wild-type proSP-C isoform was similar to that of the longer isoform, but the half-life of the mutated shorter isoform was decreased. These results suggest a direct effect of GC on proSP-C metabolism through reducing the SFTPC mRNA level and favouring the expression of a less stable protein isoform.
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Affiliation(s)
- Céline Delestrain
- Université Paris Est Creteil, INSERM, IMRB, F-94010 Creteil, France.,Centre Hospitalier Intercommunal de Créteil, Service de Pédiatrie Générale, Créteil, 94000, France.,FHU SENEC, Créteil, France
| | - Abdel Aissat
- Université Paris Est Creteil, INSERM, IMRB, F-94010 Creteil, France.,FHU SENEC, Créteil, France.,AP-HP, Hôpital Henri Mondor, Pôle de Biologie-Pathologie, Département de Génétique, Créteil, 94000, France
| | - Stéphanie Simon
- Université Paris Est Creteil, INSERM, IMRB, F-94010 Creteil, France
| | - Agathe Tarze
- Université Paris Est Creteil, INSERM, IMRB, F-94010 Creteil, France
| | - Elodie Duprat
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, CNRS, Sorbonne Université, Muséum National d'Histoire Naturelle, Paris, France
| | - Elodie Nattes
- Université Paris Est Creteil, INSERM, IMRB, F-94010 Creteil, France.,Centre Hospitalier Intercommunal de Créteil, Service de Pédiatrie Générale, Créteil, 94000, France.,FHU SENEC, Créteil, France
| | - Bruno Costes
- Université Paris Est Creteil, INSERM, IMRB, F-94010 Creteil, France.,FHU SENEC, Créteil, France.,AP-HP, Hôpital Henri Mondor, Pôle de Biologie-Pathologie, Département de Génétique, Créteil, 94000, France
| | - Valérie Delattre
- AP-HP, Hôpital Henri Mondor, Pôle de Biologie-Pathologie, Département de Génétique, Créteil, 94000, France
| | - Stéphanie Finet
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, CNRS, Sorbonne Université, Muséum National d'Histoire Naturelle, Paris, France
| | - Pascale Fanen
- Université Paris Est Creteil, INSERM, IMRB, F-94010 Creteil, France.,FHU SENEC, Créteil, France.,AP-HP, Hôpital Henri Mondor, Pôle de Biologie-Pathologie, Département de Génétique, Créteil, 94000, France
| | - Ralph Epaud
- Université Paris Est Creteil, INSERM, IMRB, F-94010 Creteil, France.,Centre Hospitalier Intercommunal de Créteil, Service de Pédiatrie Générale, Créteil, 94000, France.,FHU SENEC, Créteil, France
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4
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Shu L, Guo X, Niu L, Chen X, Cai T, Ding X, Xie Z, Wang J, Zhu N, Kou T, Yang F. Comprehensive characterization and proteoform analysis of the hydrophobic surfactant proteins B and C in calf pulmonary surfactant. J Pharm Biomed Anal 2019; 174:625-632. [PMID: 31276983 DOI: 10.1016/j.jpba.2019.06.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 06/19/2019] [Accepted: 06/20/2019] [Indexed: 01/11/2023]
Abstract
Calf pulmonary surfactant (CPS), which contains about 98% lipids and 2% hydrophobic surfactant proteins B (SP-B) and C (SP-C), has been used as a surfactant preparation for the clinical replacement therapy of respiratory distress syndrome (RDS). Characterization of SP-B and SP-C in CPS is informative for quality control and the evaluation of their biological activities. However, analysis of SP-B and SP-C is impeded by the high content of lipids in CPS. Here, we describe an integrated method by combining size exclusion chromatography (SEC)-based delipidation, SDS-PAGE separation, in-gel digestion and mass spectrometric analysis for comprehensive characterization and proteoform analysis of the extremely hydrophobic SP-B and SP-C in CPS. This study has shown that 30 proteoforms of SP-C with different truncations and modifications were identified and SP-B was found to be existed as a dimer form in the CPS.
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Affiliation(s)
- Lian Shu
- Key Laboratory of Protein and Peptide Pharmaceuticals & Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaojing Guo
- Key Laboratory of Protein and Peptide Pharmaceuticals & Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lili Niu
- Key Laboratory of Protein and Peptide Pharmaceuticals & Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiulan Chen
- Key Laboratory of Protein and Peptide Pharmaceuticals & Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tanxi Cai
- Key Laboratory of Protein and Peptide Pharmaceuticals & Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiang Ding
- Key Laboratory of Protein and Peptide Pharmaceuticals & Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhensheng Xie
- Key Laboratory of Protein and Peptide Pharmaceuticals & Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jifeng Wang
- Key Laboratory of Protein and Peptide Pharmaceuticals & Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Nali Zhu
- Key Laboratory of Protein and Peptide Pharmaceuticals & Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tongxin Kou
- China Resources Double-crane Pharmaceutical Co. Ltd. Beijing, 100102, China
| | - Fuquan Yang
- Key Laboratory of Protein and Peptide Pharmaceuticals & Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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5
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Beers MF, Moodley Y. When Is an Alveolar Type 2 Cell an Alveolar Type 2 Cell? A Conundrum for Lung Stem Cell Biology and Regenerative Medicine. Am J Respir Cell Mol Biol 2017; 57:18-27. [PMID: 28326803 DOI: 10.1165/rcmb.2016-0426ps] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Generating mature, differentiated, adult lung cells from pluripotent cells, such as induced pluripotent stem cells and embryonic stem cells, offers the hope of both generating disease-specific in vitro models and creating definitive and personalized therapies for a host of debilitating lung parenchymal and airway diseases. With the goal of advancing lung-regenerative medicine, several groups have developed and reported on protocols using defined media, coculture with mesenchymal components, or sequential treatments mimicking lung development, to obtain distal lung epithelial cells from stem cell precursors. However, there remains significant controversy about the degree of differentiation of these cells compared with their primary counterparts, coupled with a lack of consistency or uniformity in assessing the resultant phenotypes. Given the inevitable, exponential expansion of these approaches and the probable, but yet-to-emerge second and higher generation techniques to create such assets, we were prompted to pose the question, what makes a lung epithelial cell a lung epithelial cell? More specifically for this Perspective, we also posed the question, what are the minimum features that constitute an alveolar type (AT) 2 epithelial cell? In addressing this, we summarize a body of work spanning nearly five decades, amassed by a series of "lung epithelial cell biology pioneers," which carefully describes well characterized molecular, functional, and morphological features critical for discriminately assessing an AT2 phenotype. Armed with this, we propose a series of core criteria to assist the field in confirming that cells obtained following a differentiation protocol are indeed mature and functional AT2 epithelial cells.
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Affiliation(s)
- Michael F Beers
- 1 Lung Epithelial Biology Laboratories, Penn Center for Pulmonary Biology, Pulmonary and Critical Care Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - Yuben Moodley
- 2 University of Western Australia, Harry Perkins Research Institute, Fiona Stanley Hospital, Murdoch, Western Australia, Australia
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6
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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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7
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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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8
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Zhou Q, Xiong Y, Huang XR, Tang P, Yu X, Lan HY. Identification of Genes Associated with Smad3-dependent Renal Injury by RNA-seq-based Transcriptome Analysis. Sci Rep 2015; 5:17901. [PMID: 26648110 PMCID: PMC4673424 DOI: 10.1038/srep17901] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/04/2015] [Indexed: 01/14/2023] Open
Abstract
Transforming growth factor-β/Smad3 signaling plays a critical role in the process of chronic kidney disease (CKD), but targeting Smad3 systematically may cause autoimmune disease by impairing immunity. In this study, we used whole-transcriptome RNA-sequencing to identify the differential gene expression profile, gene ontology, pathways, and alternative splicing related to TGF-β/Smad3 in CKD. To explore common dysregulation of genes associated with Smad3-dependent renal injury, kidney tissues of Smad3 wild-type and knockout mice with immune (anti-glomerular basement membrane glomerulonephritis) and non-immune (obstructive nephropathy)-mediated CKD were used for RNA-sequencing analysis. Totally 1922 differentially expressed genes (DEGs) were commonly found in these CKD models. The up-regulated genes are inflammatory and immune response associated, while decreased genes are material or electron transportation and metabolism related. Only 9 common DEGs were found to be Smad3-dependent in two models, including 6 immunoglobulin genes (Ighg1, Ighg2c, Igkv12-41, Ighv14-3, Ighv5-6 and Ighg2b) and 3 metabolic genes (Ugt2b37, Slc22a19, and Mfsd2a). Our results identify transcriptomes associated with renal injury may represent a common mechanism for the pathogenesis of CKD and reveal novel Smad3 associated transcriptomes in the development of CKD.
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Affiliation(s)
- Qin Zhou
- Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.,Li Ka Shing Institute of Health Sciences and Department of Medicine &Therapeutics, the Chinese University of Hong Kong, Hong Kong, China
| | - Yuanyan Xiong
- State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou, China.,SYSU-CMU Shunde International Joint Research Institute, Guangzhou, China
| | - Xiao R Huang
- Li Ka Shing Institute of Health Sciences and Department of Medicine &Therapeutics, the Chinese University of Hong Kong, Hong Kong, China.,Shenzhen Research Institute, the Chinese University of Hong Kong, Shenzhen, China
| | - Patrick Tang
- Li Ka Shing Institute of Health Sciences and Department of Medicine &Therapeutics, the Chinese University of Hong Kong, Hong Kong, China
| | - Xueqing Yu
- Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Hui Y Lan
- Li Ka Shing Institute of Health Sciences and Department of Medicine &Therapeutics, the Chinese University of Hong Kong, Hong Kong, China.,Shenzhen Research Institute, the Chinese University of Hong Kong, Shenzhen, China
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9
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Altieri F, Di Stadio CS, Severino V, Sandomenico A, Minopoli G, Miselli G, Di Maro A, Ruvo M, Chambery A, Quagliariello V, Masullo M, Rippa E, Arcari P. Anti-amyloidogenic property of human gastrokine 1. Biochimie 2014; 106:91-100. [DOI: 10.1016/j.biochi.2014.08.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 08/10/2014] [Indexed: 10/24/2022]
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10
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Dodagatta-Marri E, Qaseem AS, Karbani N, Tsolaki AG, Waters P, Madan T, Kishore U. Purification of surfactant protein D (SP-D) from pooled amniotic fluid and bronchoalveolar lavage. Methods Mol Biol 2014; 1100:273-90. [PMID: 24218267 DOI: 10.1007/978-1-62703-724-2_22] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Surfactant protein SP-D is a multimeric collagenous lectin, called collectin. SP-D is a multifunctional, pattern recognition innate immune molecule, which binds in a calcium dependent manner to an array of carbohydrates and lipids, thus offering resistance to invading pathogens, allergen challenge, and pulmonary inflammation. SP-D is predominantly found in the endoplasmic reticulum of type 2 pneumocytes and in the secretory granules of Clara or non-ciliated bronchiolar cells. The highest expression of SP-D is observed in the distal airways and alveoli. There is also an extra pulmonary existence of SP-D. The common sources of native full-length human SP-D are bronchoalveolar lavage (BAL) washings from normal or preferably patients suffering from alveolar proteinosis who overproduce SP-D in the lungs. Amniotic fluid collected at the term during parturition is another reasonable source. Here, we describe a simple and rapid method of purifying native SP-D away from SP-A which is also present in the same source. We also describe procedures of expressing and purifying a recombinant fragment of human SP-D (rhSP-D) comprising trimeric neck and carbohydrate recognition domains that has been shown to have therapeutic effects in murine models of allergy and infection.
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Affiliation(s)
- Eswari Dodagatta-Marri
- Centre for Infection, Immunity and Disease Mechanisms, Biosciences, School of Health Sciences and Social Care, Brunel University, London, UK
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11
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Chavarha M, Loney RW, Kumar K, Rananavare SB, Hall SB. Differential effects of the hydrophobic surfactant proteins on the formation of inverse bicontinuous cubic phases. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:16596-604. [PMID: 23140329 PMCID: PMC3514604 DOI: 10.1021/la3025364] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Prior studies have shown that the biological mixture of the two hydrophobic surfactant proteins, SP-B and SP-C, produces faster adsorption of the surfactant lipids to an air/water interface, and that they induce 1-palmitoyl-2-oleoyl phosphatidylethanolamine (POPE) to form inverse bicontinuous cubic phases. Previous studies have shown that SP-B has a much greater effect than SP-C on adsorption. If the two proteins induce faster adsorption and formation of the bicontinuous structures by similar mechanisms, then they should also have different abilities to form the cubic phases. To test this hypothesis, we measured small-angle X-ray scattering on the individual proteins combined with POPE. SP-B replicated the dose-related ability of the combined proteins to induce the cubic phases at temperatures more than 25 °C below the point at which POPE alone forms the curved inverse-hexagonal phase. With SP-C, diffraction from cubic structures was either absent or present at very low intensities only with larger amounts of protein. The correlation between the structural effects of inducing curved structures and the functional effects on the rate of adsorption fits with the model in which SP-B promotes adsorption by facilitating formation of an inversely curved, rate-limiting structure.
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Affiliation(s)
- Mariya Chavarha
- Departments of Biochemistry & Molecular Biology, Medicine, and Physiology & Pharmacology, Oregon Health & Science University, Portland, OR 97239-3098
| | - Ryan W. Loney
- Departments of Biochemistry & Molecular Biology, Medicine, and Physiology & Pharmacology, Oregon Health & Science University, Portland, OR 97239-3098
| | - Kamlesh Kumar
- Departments of Biochemistry & Molecular Biology, Medicine, and Physiology & Pharmacology, Oregon Health & Science University, Portland, OR 97239-3098
| | | | - Stephen B. Hall
- Departments of Biochemistry & Molecular Biology, Medicine, and Physiology & Pharmacology, Oregon Health & Science University, Portland, OR 97239-3098
- To whom correspondence should be addressed: Stephen B. Hall, Pulmonary & Critical Care Medicine, Mail Code UHN-67, Oregon Health & Science University, Portland, Oregon 97239-3098, Telephone: (503) 494-6667,
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12
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Simonato M, Baritussio A, Vedovelli L, Lamonica G, Carnielli VP, Cogo PE. Surfactant protein B amount and kinetics in newborn infants: an optimized procedure. JOURNAL OF MASS SPECTROMETRY : JMS 2012; 47:1415-1419. [PMID: 23147816 DOI: 10.1002/jms.3065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Surfactant protein B (SP-B) plays a key role in surfactant homeostasis affecting its biophysical properties and physiological function. Recently, a method to measure SP-B amount and kinetics from tracheal aspirates (TAs) became available. The main objective of this study was to improve the critical steps of the procedure to obtain a better SP-B sensitivity. We administered a 24 h continuous infusion of 1 mg/kg/h of 1(13)C-leucine to ten newborn infants. SP-B was isolated from serial TAs and its fractional synthesis rate, secretion time, peak time and half life were derived from (13)C enrichment curves obtained by gas chromatography mass spectrometry. SP-B amount in TAs was also assessed. During the extraction step, acidification and organic solvent ratio optimization doubled the recovery of SP-B from TAs, so did the elongation of the propylation time (from 20 min to 1 h) with enhanced leucine derivatization yield. Measurement of (13)C leucine enrichments, and therefore all SP-B kinetics parameters, were successfully calculated in all TAs samples due to the increase of SP-B yield. SP-B amount was 0.29 (0.16-0.41) % of total phospholipids with a minimum value of 0.08% belonging to one of the respiratory distress syndrome (RDS) patients. In conclusion, this new procedure enables accurate determination of SP-B kinetics even in the presence of low protein amount like in preterm RDS patients.
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Affiliation(s)
- Manuela Simonato
- Department of Medicine, Anaesthesia and Critical Care, University of Padova, Padova, Italy.
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13
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Maguire JA, Mulugeta S, Beers MF. Multiple ways to die: delineation of the unfolded protein response and apoptosis induced by Surfactant Protein C BRICHOS mutants. Int J Biochem Cell Biol 2011; 44:101-12. [PMID: 22016030 DOI: 10.1016/j.biocel.2011.10.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 09/22/2011] [Accepted: 10/06/2011] [Indexed: 02/06/2023]
Abstract
Epithelial cell dysfunction is now recognized as an important mechanism in the pathogenesis of interstitial lung diseases. Surfactant Protein C (SP-C), an alveolar type II cell specific protein, has contributed to this concept with the observation that heterozygous expression of SFTPC gene mutations are associated with chronic interstitial lung disease. We have shown that transient expression of aggregation prone mutant SP-C isoforms (SP-C BRICHOS) destabilize ER quality control mechanisms resulting in the intracellular accumulation of aggregating propeptide, inhibition of the ubiquitin/proteasome system, and activation of apoptosis. The goal of the present study was to define signaling pathways linking the unfolded protein response (UPR) and subsequent ER stress with intrinsic apoptosis events observed following mutant SP-C expression. In vitro expression of the SP-C BRICHOS mutant, SP-C(Δexon4), was used as a model system. Here we show stimulation of a broad ER stress response in both transfected A549 and HEK293 cells with activation of all 3 canonical sensing pathways, IRE1/XBP-1, ATF6, and PERK/eIF2α. SP-C(Δexon4) expression also resulted in activation of caspase 3, but failed to stimulate expression of the apoptosis mediating transcription factors ATF4/CHOP. However, inhibition of either caspase 4 or c-jun kinase (JNK) each blocked caspase 3 mediated cell death. Taken together, these results suggest that expression of SP-C BRICHOS mutants induce apoptosis through multiple UPR signaling pathways, and provide new therapeutic targets for the amelioration of ER stress induced cytotoxicity observed in fibrotic lung remodeling.
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Affiliation(s)
- Jean Ann Maguire
- Pulmonary and Critical Care Division, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-4539, United States
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14
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de la Fuente AA, Voorhout WF, deMello DE. Congenital Alveolar Proteinosis in the Netherlands: A Report of Five Cases with Immunohistochemical and Genetic Studies on Surfactant Apoproteins. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/15513819709168567] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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15
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Kotorashvili A, Russo SJ, Mulugeta S, Guttentag S, Beers MF. Anterograde transport of surfactant protein C proprotein to distal processing compartments requires PPDY-mediated association with Nedd4 ubiquitin ligases. J Biol Chem 2009; 284:16667-16678. [PMID: 19366705 PMCID: PMC2713532 DOI: 10.1074/jbc.m109.002816] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 04/02/2009] [Indexed: 11/06/2022] Open
Abstract
Biosynthesis of surfactant protein C (SP-C) by alveolar type 2 cells requires proteolytic processing of a 21-kDa propeptide (proSP-C21) in post-Golgi compartments to yield a 3.7-kDa mature form. Scanning alanine mutagenesis, binding assays, and co-immunoprecipitation were used to characterize the proSP-C targeting domain. Delivery of proSP-C21 to distal processing organelles is dependent upon the NH2-terminal cytoplasmic SP-C propeptide, which contains a conserved PPDY motif. In A549 cells, transfection of EGFP/proSP-C21 constructs containing polyalanine substitution for Glu11-Thr18, 13PPDY16, or 14P,16Y produced endoplasmic reticulum retention of the fusion proteins. Protein-protein interactions of proSP-C with known WW domains were screened using a solid-phase array that revealed binding of the proSP-C NH2 terminus to several WW domains found in the Nedd4 family of E3 ligases. Specificity of the interaction was confirmed by co-immunoprecipitation of proSP-C and Nedd4 or Nedd4-2 in epithelial cell lines. By Western blotting and reverse transcription-PCR, both forms were detected in primary human type 2 cells. Knockdown of Nedd4-2 by small interference RNA transfection of cultured human type 2 cells blocked processing of 35S-labeled proSP-C21. Mutagenesis of potential acceptor sites for ubiquitination in the cytosolic domain of proSP-C (Lys6, Lys34, or both) failed to inhibit trafficking of EGFP/proSP-C21. These results indicate that PPDY-mediated interaction with Nedd4 E3-ligases is required for trafficking of proSP-C. We speculate that the Nedd4/proSP-C tandem is part of a larger protein complex containing a ubiquitinated component that further directs its transport.
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Affiliation(s)
- Adam Kotorashvili
- From the Surfactant Biology Laboratories, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Scott J Russo
- From the Surfactant Biology Laboratories, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Surafel Mulugeta
- From the Surfactant Biology Laboratories, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Susan Guttentag
- Division of Neonatology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Michael F Beers
- From the Surfactant Biology Laboratories, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104.
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16
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Darine S, Christophe V, Gholamreza D. Production and functional properties of beef lung protein concentrates. Meat Sci 2009; 84:315-22. [PMID: 20374791 DOI: 10.1016/j.meatsci.2009.03.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 02/16/2009] [Accepted: 03/22/2009] [Indexed: 11/16/2022]
Abstract
This work investigated the production and the properties of meat protein concentrates from beef lungs (BLPC) at pilot scale. Protein recovery and functional properties were compared to those of BLPC obtained using membrane technology in a previous work (Selmane, D., Vial, C., & Djelveh, G. (2008). Extraction of proteins from slaughterhouse by-products: Influence of operating conditions on functional properties. Meat Science, 79, 640-647). An alkaline solubilisation method was applied for protein extraction, followed by pI precipitation for concentration. The physicochemical properties of BLPC such as molecular mass, solubility, surface hydrophobicity, surface tension and interfacial tension, as well as technofunctional emulsifying and foaming properties were determined. These were compared to those of commercial protein ingredients, such as sodium caseinates, whey protein isolates, egg white proteins and soy protein isolates. Results showed that proteins from BLPC included a low-molecular-weight fraction and exhibited good solubility and high hydrophobicity with small surface and interfacial tensions. This explained their excellent emulsifying activity, better than sodium caseinates, and their good foaming properties.
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Affiliation(s)
- Selmane Darine
- LGCB, Clermont Université/ENSCCF, 24 av. des Landais, BP 206, 63174 Aubière Cedex, France.
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17
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Galetskiy D, Woischnik M, Ripper J, Griese M, Przybylski M. Aberrant processing forms of lung surfactant proteins SP-B and SP-C revealed by high-resolution mass spectrometry. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2008; 14:379-390. [PMID: 19136726 DOI: 10.1255/ejms.957] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The mutation (g.1286T>C) of the pulmonary surfactant-associated protein C gene (SFTPC) leads to the I73T substitution in the precursor protein (pro-SP-C) and results in interstitial lung disease with the histological pattern of non-specific interstitial pneumonia and pulmonary alveolar proteinosis. Central for the disease is the abnormal processing of the SP-C pro-protein to mature SP-C; however little is known about the nature of intermediates and processing products. We report here the application of high resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry to the characterization of processing intermediates of hydrophobic pulmonary surfactant proteins SP-B and SP-C in intra- alveolar surfactant material of a patient with I73T mutation. SP-C and SP-B processing forms were separated from broncho-alveolar lavage fluid using chloroform/methanol extraction and sodium dodecyl sulfate poly acrylamide gel electrophoreis, detected by Western blot and identified by electrospray- and matrix-assisted laser desorption/ionization-FT-ICR mass spectrometry. The mass spectrometric and immuno-analytical results show the intra-alveolar accumulation of an aberrant C-terminal SP-C processing products in which the mature SP-C protein part is missing and aberrant processing intermediates of SP-B.
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Affiliation(s)
- Dmitry Galetskiy
- Laboratory of Analytical Chemistry and Biopolymer Structure Analysis, Department of Chemistry, University of Konstanz, Box M 73178457 Konstanz, Germany
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18
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Bullard JE, Nogee LM. Heterozygosity for ABCA3 mutations modifies the severity of lung disease associated with a surfactant protein C gene (SFTPC) mutation. Pediatr Res 2007; 62:176-9. [PMID: 17597647 DOI: 10.1203/pdr.0b013e3180a72588] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Heterozygous SFTPC mutations have been associated with adult and pediatric interstitial lung disease (pILD). Inheritance is autosomal dominant, but de novo mutations may cause sporadic disease. SFTPC mutations have been associated with variable onset of symptoms, ranging from early infancy to late adulthood. The underlying mechanisms for this variability are unknown. Recently, mutations in ABCA3 (encoding member A3 of the adenosine triphosphate-binding cassette family of transporters) were identified as a cause of pILD. To test the hypothesis that ABCA3 mutations modify the severity of lung disease in individuals with SFTPC mutations, we sequenced ABCA3 from four symptomatic infants with the same SFTPC mutation, a substitution of isoleucine by threonine in codon 73 (I73T). Each infant developed respiratory symptoms by 2 mo of age and inherited the mutation from an asymptomatic parent. Three of the four infants were also heterozygous for an ABCA3 mutation, which was inherited from the parent without SFTPC I73T. The finding of heterozygosity for ABCA3 mutations in severely affected infants with SFTPC I73T, and independent inheritance from disease-free parents supports that ABCA3 acts as a modifier gene for the phenotype associated with an SFTPC mutation.
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Affiliation(s)
- Janine E Bullard
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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19
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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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20
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Ruppert C, Bagheri A, Markart P, Schmidt R, Seeger W, Günther A. Liver carboxylesterase cleaves surfactant protein (SP-) B and promotes surfactant subtype conversion. Biochem Biophys Res Commun 2006; 348:1449-54. [PMID: 16919595 DOI: 10.1016/j.bbrc.2006.08.013] [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] [Received: 07/31/2006] [Accepted: 08/04/2006] [Indexed: 11/21/2022]
Abstract
Conversion of the biophysically active large surfactant aggregate subtype of alveolar surfactant into the less surface active small surfactant aggregates occurs in vitro and in vivo, possibly in dependency of a carboxylesterase, entitled surfactant convertase. The substrate has yet not been safely identified. Utilizing the in vitro cycling assay we investigated conversion of an organic rabbit lavage extract reconstituted with SP-A. Porcine liver carboxylesterase, which is closely related to surfactant convertase, induced subtype conversion to a similar degree as compared with native lavage fluid containing endogenous convertase. In addition, we asked for cleavage products of SP-B and identified a approximately 12 kDa band upon cycling with liver carboxylesterase, having the same N-terminus as mature SP-B. A band of same molecular weight was found in native lavage fluid after in vitro conversion mediated by the endogenous convertase. We conclude that SP-B plays a pivotal role during subtype conversion and represents the substrate for surfactant convertase.
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Affiliation(s)
- Clemens Ruppert
- University of Giessen Lung Center (UGLC), Department of Internal Medicine, Medical Clinic II, Justus-Liebig University, Giessen, Germany
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21
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Abstract
PURPOSE OF REVIEW The interstitial lung diseases are a heterogeneous group of rare disorders of largely unknown etiology. The occurrence of familial cases of pediatric interstitial lung diseases with the onset of symptoms developing early in infancy has suggested a genetic basis for some forms of interstitial lung diseases in children. RECENT FINDINGS Mutations in the genes encoding surfactant protein C, SFTPC, and a member of the adenosine triphosphate-binding cassette family of proteins, ABCA3, have been shown to result in pediatric interstitial lung diseases inherited in autosomal-dominant and autosomal-recessive patterns, respectively. There is overlap in both the clinical and histopathologic features of these disorders. SUMMARY Identification of genes responsible for pediatric interstitial lung diseases provides the opportunity for noninvasive testing to establish an etiologic diagnosis, to counsel family members for their recurrence risk, and to classify these rare disorders more accurately. A better understanding of the cause and pathophysiology of these disorders may provide additional insights into the causes of other forms of pediatric interstitial lung diseases, and may suggest novel treatment approaches.
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Affiliation(s)
- Lawrence M Nogee
- Division of Neonatology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
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22
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Kankavi O, Ata A, Gungor O. Surfactant proteins A and D in the genital tract of mares. Anim Reprod Sci 2006; 98:259-70. [PMID: 16621351 DOI: 10.1016/j.anireprosci.2006.03.009] [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] [Received: 11/08/2005] [Revised: 01/26/2006] [Accepted: 03/13/2006] [Indexed: 11/18/2022]
Abstract
The presence of surface-active material in the lung alveolus has been known for several decades as being essential for normal lung function. Surfactant is essential for reducing the surface tension at the alveolar air-liquid interface. Pulmonary surfactant is composed of 90% lipids and 10% proteins. There are four non-serum proteins surfactant protein-A (SP-A), surfactant protein-B (SP-B), surfactant protein-C (SP-C) and surfactant protein-D (SP-D) named in chronologic order of discovery. Lung SP-A and SP-D belong to a family of collagen-containing C-type lectin family called collectins. The host defence and controlling inflammatory processes of the lung are the major functions of SP-A and SP-D. SP-A and SP-D were originally demonstrated in alveolar type II cells, but recent studies have shown extrapulmonary expression of SP-A and SP-D indicating systemic roles of these proteins. Present study describes the presence of SP-A and SP-D in the mare genital tract, vulva, vagina, ovarium, uterus and tuba uterina using immunohistochemistry and Western blotting. The aim of this study was to characterize surfactant proteins in terms of: (i) whether surfactant proteins were present in the various structures of the mare genital system, (ii) if so, identifying and locating the surfactant proteins and finally (iii) determining the differences from those previously characterized for the lung. Although beyond the scope of this report, it is recognized that there are also some potential implications for better defining the reproductive defence mechanisms in mare. Therefore, genital system organs and tissues from mares were examined. We were able to show that proteins reactive with surfactant-specific antibodies were present in the mare genital tract. Thus, surfactant proteins are present not in just lamellar bodies associated with lung, but also genital system of mare.
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Affiliation(s)
- Orhan Kankavi
- Department of Biochemistry, Burdur Faculty of Veterinary Medicine, The University of Akdeniz, 15100 Burdur, Turkey.
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23
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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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24
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Merkulova MI, Radchenko VV, Il'nitsaia EV, Shuvaeva TM, Lipkin VM. [A proteomic approach to study of the function of the Sec14p-like p45 protein]. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2005; 31:280-7. [PMID: 16004386 DOI: 10.1007/s11171-005-0034-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We undertook a search for proteins interacting with protein p45 by the method of two-hybrid screening in order to determine the function of the Sec14p-like protein p45. A screening of the yeast library of rat lung cDNA, six proteins specifically activating the reporter genes of a two-hybrid system and 21 unlikely protein partners of protein p45 were identified. The most likely candidate for the role of a p45 partner is the surfactant protein C (Sftpc). These results and previous studies led us to the hypothesis that protein p45 fulfills its protective function by participating in the biogenesis of cell membranes. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2005, vol. 31, no. 3; see also http://www.maik.ru.
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25
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Hartl D, Griese M. Interstitial lung disease in children -- genetic background and associated phenotypes. Respir Res 2005; 6:32. [PMID: 15819986 PMCID: PMC1090616 DOI: 10.1186/1465-9921-6-32] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2005] [Accepted: 04/08/2005] [Indexed: 11/10/2022] Open
Abstract
Interstitial lung disease in children represents a group of rare chronic respiratory disorders. There is growing evidence that mutations in the surfactant protein C gene play a role in the pathogenesis of certain forms of pediatric interstitial lung disease. Recently, mutations in the ABCA3 transporter were found as an underlying cause of fatal respiratory failure in neonates without surfactant protein B deficiency. Especially in familiar cases or in children of consanguineous parents, genetic diagnosis provides an useful tool to identify the underlying etiology of interstitial lung disease. The aim of this review is to summarize and to describe in detail the clinical features of hereditary interstitial lung disease in children. The knowledge of gene variants and associated phenotypes is crucial to identify relevant patients in clinical practice.
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Affiliation(s)
- Dominik Hartl
- Pediatric Pneumology, Childrens' hospital of the Ludwig-Maximilians-University, Munich, Germany
| | - Matthias Griese
- Pediatric Pneumology, Childrens' hospital of the Ludwig-Maximilians-University, Munich, Germany
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26
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Mulugeta S, Nguyen V, Russo SJ, Muniswamy M, Beers MF. A surfactant protein C precursor protein BRICHOS domain mutation causes endoplasmic reticulum stress, proteasome dysfunction, and caspase 3 activation. Am J Respir Cell Mol Biol 2005; 32:521-30. [PMID: 15778495 PMCID: PMC2715321 DOI: 10.1165/rcmb.2005-0009oc] [Citation(s) in RCA: 200] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
BRICHOS is a domain found in several proteins consisting of approximately 100 amino acids with sequence and structural similarities. Mutations in BRICHOS domain have been associated with both degenerative and proliferative diseases in several nonpulmonary organs, although the pathogenic mechanisms are largely undefined. Recently, several mutations in surfactant protein C (SP-C) mapping to the BRICHOS domain located within the proprotein (proSP-C) have been linked to interstitial lung diseases. In vitro expression of one of these BRICHOS mutants, the exon 4 deletion (hSP-CDeltaexon4), promotes a dominant-negative perinuclear aggregation of the protein. The present study characterizes the trafficking behavior and pathogenic consequences resulting from hSP-CDeltaexon4 expression. Time-lapse and co-localization microscopy studies demonstrated enhanced green fluorescent protein (EGFP)/hSP-CDeltaexon4 expression in calnexin-positive (endoplasmic reticulum [ER]) compartment with subsequent time- and concentration-dependent development of ubiquitinated perinuclear inclusion bodies followed by apoptosis. Compared with controls, EGFP/hSP-CDeltaexon4 promoted upregulation of multiple ER stress species, activated caspase 3, and induced annexin V binding. Furthermore, in GFP-u cells, hSP-CDeltaexon4 directly inhibited proteasome activity. These results support a model whereby proSP-C BRICHOS mutations induce a dynamic toxic gain-of-function, causing apoptotic cell death both by early ER accumulation leading to an exaggerated unfolded protein response and by enhanced deposition of cellular aggregates associated with proteasome dysfunction.
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Affiliation(s)
- Surafel Mulugeta
- Pulmonary and Critical Care Division, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6160, USA.
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27
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Abstract
Surfactant protein C (SP-C) is a hydrophobic 35-amino acid peptide that co-isolates with the phospholipid fraction of lung surfactant. SP-C represents a structurally and functionally challenging protein for the alveolar type 2 cell, which must synthesize, traffic, and process a 191-197-amino acid precursor protein through the regulated secretory pathway. The current understanding of SP-C biosynthesis considers the SP-C proprotein (proSP-C) as a hybrid molecule that incorporates structural and functional features of both bitopic integral membrane proteins and more classically recognized luminal propeptide hormones, which are subject to post-translational processing and regulated exocytosis. Adding to the importance of a detailed understanding of SP-C biosynthesis has been the recent association of mutations in the proSP-C sequence with chronic interstitial pneumonias in children and adults. Many of these mutations involve either missense or deletion mutations located in a region of the proSP-C molecule that has structural homology to the BRI family of proteins linked to inherited degenerative dementias. This review examines the current state of SP-C biosynthesis with a focus on recent developments related to molecular and cellular mechanisms implicated in the emerging role of SP-C mutations in the pathophysiology of diffuse parenchymal lung disease.
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Affiliation(s)
- Michael F Beers
- Pulmonary and Critical Care Division, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6061, USA.
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28
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Stevens PA, Pettenazzo A, Brasch F, Mulugeta S, Baritussio A, Ochs M, Morrison L, Russo SJ, Beers MF. Nonspecific interstitial pneumonia, alveolar proteinosis, and abnormal proprotein trafficking resulting from a spontaneous mutation in the surfactant protein C gene. Pediatr Res 2005; 57:89-98. [PMID: 15557112 DOI: 10.1203/01.pdr.0000147567.02473.5a] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Human surfactant protein C (hSP-C(1-197)) is synthesized as a 197 amino acid proprotein and cleaved to a mature 3.7 kD form. Although interstitial lung disease in patients with mutations of the hSP-C gene is becoming increasingly recognized, the mechanisms linking molecular events with clinical pathogenesis are not fully defined. We describe a full-term infant with respiratory insufficiency associated with a spontaneous heterozygous mutation resulting in a substitution of lysine for glutamic acid at position 66 (= E66K) of the proximal hSP-C COOH flanking propeptide. Lung histology and biochemical studies of the index patient (hSP-C(E66K)) revealed nonspecific interstitial pneumonia, increased alveolar total phospholipid lacking phosphatidylglycerol, and increased surfactant protein A. Localization of proSP-C from lung sections prepared from this patient using immunofluorescence and immunogold electron microscopy revealed abnormal proSP-C staining in endosomal-like vesicles of type II cells distinct from SP-B. To evaluate the effect of the E66K substitution on intracellular trafficking of proSP-C, fusion proteins consisting of enhanced green fluorescent protein (EGFP) and hSP-C(1-197) (wild type) or mutant hSP-C(E66K) were generated and transfected into A549 cells. EGFP/hSP-C(1-197) was expressed within CD-63-positive, EEA-1-negative vesicles, whereas EGFP/hSP-C(E66K) localized to EEA-1 positive vesicles. The E66K substitution is representative of a new class of SP-C mutation associated with interstitial lung disease that is diverted from the normal biosynthetic pathway. We propose that, similar to other storage disorders, lung injury results from induction of a toxic gain of function induced by the mutant product that is subject to genetic modifiers and environmental influences.
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MESH Headings
- Blotting, Western
- Bronchoalveolar Lavage
- Cell Line, Tumor
- DNA/metabolism
- DNA Primers/chemistry
- DNA, Complementary/metabolism
- Electrophoresis, Polyacrylamide Gel
- Glutamic Acid/chemistry
- Green Fluorescent Proteins/metabolism
- Humans
- Immunoblotting
- Immunohistochemistry
- Infant
- Lung/pathology
- Lung Diseases, Interstitial/genetics
- Lung Diseases, Interstitial/pathology
- Lysine/chemistry
- Male
- Microscopy, Fluorescence
- Microscopy, Immunoelectron
- Microscopy, Phase-Contrast
- Models, Biological
- Mutation
- Phospholipids/metabolism
- Protein Transport
- Pulmonary Alveolar Proteinosis/genetics
- Pulmonary Alveolar Proteinosis/pathology
- Pulmonary Surfactant-Associated Protein C/genetics
- Recombinant Fusion Proteins/metabolism
- Surface-Active Agents/metabolism
- Time Factors
- Tomography, X-Ray Computed
- Transfection
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Affiliation(s)
- Paul A Stevens
- Pulmonary and Critical Care Division, University of Pennsylvania School of Medicine, 421 Curie Blvd., Philadelphia, PA 19104-6160, USA
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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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Lahti M, Marttila R, Hallman M. Surfactant protein C gene variation in the Finnish population - association with perinatal respiratory disease. Eur J Hum Genet 2004; 12:312-20. [PMID: 14735158 DOI: 10.1038/sj.ejhg.5201137] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Surfactant protein C (SP-C) is a small hydrophobic protein component of alveolar surfactant, a lipid-protein complex lining the alveolar surface of the lung. Surfactant deficiency is the main cause of respiratory distress syndrome (RDS) in premature infants. RDS is a major risk factor of a chronic lung disease called bronchopulmonary dysplasia (BPD). The dominant mutations of the SP-C gene have recently been associated with interstitial lung diseases. However, the common genetic variation in the surfactant protein C gene has not been studied in detail. In the present study, the exonic variation of the SP-C gene in the Finnish population (n=472) was defined, and the association of the allelic variants with the susceptibility to RDS and BPD was examined. Conformation-sensitive gel electrophoresis (CSGE) was used to determine the extent of exonic variation in the SP-C gene. Methods of genotyping were generated for three biallelic polymorphisms of the SP-C gene's exons 1, 4 and 5, which encode proSP-C. The frequencies of these polymorphisms were evaluated in a study population consisting of 158 DNA samples from full-term infants. In addition, the linkage disequilibrium between the SP-C alleles was evaluated by haplotype analysis of parent-infant triplets. The role of SP-C gene variation in RDS and in BPD was evaluated in a high-risk population of 245 premature infants. According to the present results, the SP-C polymorphisms were associated with RDS and with very premature birth. The strength of allelic associations differed according to the gender of the premature infants.
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Affiliation(s)
- Meri Lahti
- Department of Pediatrics and Biocenter Oulu, University of Oulu, Oulu, Finland
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31
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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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32
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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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33
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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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Abstract
The hydrophobic surfactant proteins, SP-B and SP-C, have important roles in surfactant function. The importance of these proteins in normal lung function is highlighted by the lung diseases associated with abnormalities in their expression. Mutations in the gene encoding SP-B result in severe, fatal neonatal lung disease, and mutations in the gene encoding SP-C are associated with chronic interstitial lung diseases in newborns, older children, and adults. This work reviews the current state of knowledge concerning the lung diseases associated with mutations in the SP-B and SP-C genes, and the potential roles of abnormal SP-B and SP-C expression and genetic variation in these genes in other lung diseases.
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Affiliation(s)
- Lawrence M Nogee
- Division of Neonatology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-3200, USA.
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Tredano M, Griese M, Brasch F, Schumacher S, de Blic J, Marque S, Houdayer C, Elion J, Couderc R, Bahuau M. Mutation of SFTPC in infantile pulmonary alveolar proteinosis with or without fibrosing lung disease. Am J Med Genet A 2004; 126A:18-26. [PMID: 15039969 DOI: 10.1002/ajmg.a.20670] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Pulmonary surfactant protein C (SP-C) is a highly hydrophobic peptide produced by type-II alveolar cells through the processing of a high-molecular weight precursor (pro-SP-C), that enhances surface tension and facilitates the recycling of pulmonary surfactant in vitro. Recently, two seemingly dominant-negative mutations of the pro-SP-C-encoding gene (SFTPC, MIM 178620), were reported in families with vertically-inherited interstitial lung disease (Nogee et al. [2001: N Engl J Med 344:573-579]; Thomas et al. [2002: Am J Respir Crit Care Med 165:1322-1328]). We have examined the SP-C protein and its precursor as well as the encoding gene, in a cohort of 34 sporadic or familial cases with unexplained respiratory distress (URD) in which surfactant protein B (SP-B) deficiency related to SFTPB mutation had been ruled out. One patient with complete SP-C deficiency had no detectable mutation of SFTPC. Of the 10 patients with abnormal pro-SP-C processing, as suggested from analysis of broncho-alveolar lavage (BAL) fluid, two distinct heterozygous SFTPC missense mutations were identified. The first, g.1286T > C (p.I73T), was de novo and resulted in progressive respiratory failure with intra-alveolar storage of a granular, protein- and lipid-rich, periodic acid Schiff (PAS)-positive material (pulmonary alveolar proteinosis (PAP)), and interstitial lung disease. The second, g.2125G > A (p.R167Q), was found in two PAP patients from the endogamous white settler population of Réunion Island in which URD has an unexpectedly high prevalence. Since this mutation was diagnosed in subjects from this subpopulation who did not have evidence for lung disease, we propose environmental exposures or modifier genes to play a role in the phenotype, as suggested from murine models lacking the SP-C protein, although we cannot rule out a rare polymorphism, hitherto restricted to that subpopulation. Most remarkably, these observations extend the phenotypic spectrum related to SFTPC mutation from interstitial lung disease to PAP. Notably, the reported mutations do not appear to be dominant negatives. This article contains supplementary material, which may be viewed at the American Journal of Medical Genetics website at http://www.interscience.wiley.com/jpages/0148-7299/suppmat/index.html.
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Affiliation(s)
- Mohammed Tredano
- Service de Biochimie et Biologie Moléculaire, Hôpital d'Enfants Armand-Trousseau (AP-HP), Paris, France.
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36
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Günther A, Balser M, Schmidt R, Markart P, Olk A, Börgermann J, Splittgerber FH, Seeger W, Friedrich I. Surfactant abnormalities after single lung transplantation in dogs: impact of bronchoscopic surfactant administration. J Thorac Cardiovasc Surg 2004; 127:344-54. [PMID: 14762341 DOI: 10.1016/j.jtcvs.2002.09.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Disturbances of the alveolar surfactant system have been implicated in the pathogenesis of reperfusion injury. The aim of this study was to evaluate the influence of exogenous surfactant administration on surfactant properties in a model of single lung transplantation. METHODS We performed heterologous, left lung transplantation (+4 degrees C ischemia; 24 hours, Euro-Collins solution) in 6 foxhounds (untreated) and in 6 animals that received calf lung surfactant extract (Alveofact) prior to explantation (only donor lung; 50 mg/kg body weight) and immediately after onset of reperfusion (both lungs, 200 mg/kg body weight). Separate but synchronized ventilation of each lung was performed, in a volume-controlled, pressure-limited mode, with animals in prone position. Bronchoalveolar lavage fluids were collected in pretransplantation lungs (control), after 24 hours of ischemia prior to transplantation (0 hours) and 6 and 12 hours after reperfusion in both the grafts and the recipient native lungs. RESULTS Ischemic storage per se did not provoke any changes of the surfactant system; however, severe alterations occurred within 6 hours of reperfusion, resulting in a severe loss of surface activity, including a decrease in the percentage of the large surfactant aggregate fraction, reduction of the surfactant apoproteins SP-B and SP-C, the dipalmitoyl molecular species of phosphatidylcholine and phosphatidylglycerol within the large surfactant aggregate fraction. These abnormalities were restricted to the graft, with virtually normal surfactant function and composition being found in the recipient native lung. Surfactant administration fully normalized the biochemical and largely improved the biophysical surfactant properties, alongside maintenance of lung gas exchange properties. CONCLUSIONS Severe surfactant abnormalities occur exclusively in the graft when performing separate, synchronized ventilation of each lung to attenuate ventilator-induced lung injury. Bronchoscopic surfactant administration provides protection against these abnormalities and may be a therapeutic strategy in lung transplantation.
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Affiliation(s)
- Andreas Günther
- Department of Internal Medicine, Justus Liebig University, Giessen, Germany
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Mulugeta S, Beers MF. Processing of surfactant protein C requires a type II transmembrane topology directed by juxtamembrane positively charged residues. J Biol Chem 2003; 278:47979-86. [PMID: 12933801 DOI: 10.1074/jbc.m308210200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Surfactant protein C (SP-C) is a lung-specific protein that is synthesized as a 21-kDa integral membrane propeptide (pro-SP-C) and proteolytically processed to a 3.7-kDa secretory product. Previous studies have shown that palmitoylation of pro-SP-C is dependent on two N-terminal juxtamembrane positively charged residues. We hypothesized that these residues influence modification of pro-SP-C by directing transmembrane orientation. Double substitution mutation of these juxtaposed residues from positive to neutral charged species resulted in complete reversal of transmembrane orientation of pro-SP-C and total abrogation of post-translational processing. Mutation of a single residue resulted in mixed orientation. Protein trafficking studies in A549 cells showed that while the double mutant was retained in the endoplasmic reticulum, single mutants produced a mixed pattern of both endoplasmic reticulum (double mutant-like) and vesicular (wild type-like) expression. Our study demonstrates the crucial role juxtamembrane positively charged residues play in establishing membrane topology and their influence on the trafficking and processing of pro-SP-C. Moreover this study provides a likely precedent for a mechanism in disorders associated with mutations in the membrane-flanking region of integral membrane proteins.
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Affiliation(s)
- Surafel Mulugeta
- Lung Epithelial Cell Biology Laboratories, Pulmonary and Critical Care Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-4318, USA.
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38
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Wang WJ, Mulugeta S, Russo SJ, Beers MF. Deletion of exon 4 from human surfactant protein C results in aggresome formation and generation of a dominant negative. J Cell Sci 2003; 116:683-92. [PMID: 12538769 DOI: 10.1242/jcs.00267] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human surfactant protein C (hSP-C) is synthesized by the alveolar type 2 cell as a 197 amino acid integral membrane proprotein and proteolytically processed to a secreted 3.7 kDa mature form. Although the SP-C null mouse possesses a non-lethal phenotype, a heterozygous substitution of A for G in the first base of intron 4 of the human SP-C gene (c.460+1A>G) has been reported in association with familial interstitial lung disease and absence of mature protein. This mutation produces a splice deletion of exon 4 (deltaExon4) resulting in removal of a positionally conserved cysteine in the C-terminal flanking propeptide. Based on a prior study showing that an identical deletion in the rat isoform diverted mutant protein to stable aggregates, we hypothesized that expression of the deltaExon4 mutation would result in disruption of intracellular trafficking of both mutant and wild-type proSP-C. We tested this in vitro using fusion proteins of EGFP conjugated either to wild-type SP-C (EGFP/hSP-C(1-197)) or to SP-C deleted of Exon4 (EGFP/hSP-C(deltaExon4)). Fluorescence microscopy showed that EGFP/hSP-C(1-197) transfected into A549 cells was expressed in a punctuate pattern in CD63 (+) cytoplasmic vesicles, whereas EGFP/hSP-C(deltaExon4) accumulated in ubiquitinated perinuclear inclusions linked to the microtubule organizing center. A similar juxtanuclear pattern was observed following transfection of SP-C cDNA lacking only cysteine residues in the C-terminal propeptide encoded by Exon 4 (EGFP/hSP-C(C120/121G)). To evaluate whether mutant proSP-C could function as a dominant negative, EGFP/hSP-C(deltaExon4) was cotransfected with HA-tagged hSP-C(1-197) and resulted in the restriction of both forms to perinuclear compartments. Addition of Na(+) 4-phenylbutyrate, a facilitator of trafficking of other misfolded proteins, attenuated the aggregation of EGFP/hSP-C(deltaExon4). We conclude that c.460+1A>G mutation of human SP-C results in disruption of disulfide-mediated folding encoded by Exon 4 leading to diversion of unprocessed proSP-C to aggresomes. The heterotypic oligomerization of hSP-C(1-197) and hSP-C(deltaExon4) provides a molecular mechanism for the dominant-negative effect observed in vivo.
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Affiliation(s)
- Wen-Jing Wang
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Abstract
Neonatal lung diseases may have a genetic background. The available studies mainly concentrate on surfactant proteins (SP-A, SP-B) and respiratory distress syndrome. Specific alleles of the SP-A and SP-B genes associate interactively with susceptibility to respiratory distress syndrome. This genetic impact on the condition is influenced by environmental, acquired and inherited factors. Other alleles and genotypes of SP-A and SP-D associate with severe respiratory infections in early infancy. Rare mutations causing an absence of the SP-B protein result in progressive respiratory failure. Dominant mutations of SP-C associate with chronic lung disease, with variable manifestations. The first steps towards unraveling the genetic network influencing the susceptibility to neonatal lung diseases are now being taken. Genes encoding multifunctional proteins in the distal lung are prime candidates for causing susceptibility to neonatal lung disease, including bronchopulmonary dysplasia.
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Affiliation(s)
- Mikko Hallman
- Department of Pediatrics, University of Oulu, Kajaanintie 52A PL 5000, 90014, Oulu, Finland.
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Markart P, Ruppert C, Grimminger F, Seeger W, Günther A. Fibrinolysis-inhibitory capacity of clot-embedded surfactant is enhanced by SP-B and SP-C. Am J Physiol Lung Cell Mol Physiol 2003; 284:L69-76. [PMID: 12388357 DOI: 10.1152/ajplung.00037.2002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Incorporation of pulmonary surfactant into fibrin inhibits its plasmic degradation. In the present study we investigated the influence of surfactant proteins (SP)-A, SP-B, and SP-C on the fibrinolysis-inhibitory capacity of surfactant phospholipids. Plasmin-induced fibrinolysis was quantified by means of a (125)I-fibrin plate assay, and surfactant incorporation into polymerizing fibrin was analyzed by measuring the incorporation of (3)H-labeled L-alpha-dipalmitoylphosphatidylcholine into the insoluble clot material. Incorporation of a calf lung surfactant extract (Alveofact) and an organic extract of natural rabbit large surfactant aggregates (LSA) into a fibrin clot revealed a stronger inhibitory effect on plasmic cleavage of this clot than a synthetic phospholipid mixture (PLX) and unprocessed LSA. Reconstitution of PLX with SP-B and SP-C increased, whereas reconstitution with SP-A decreased, the fibrinolysis-inhibitory capacity of the phospholipids. The SP-B effect was paralleled by an increased incorporation of phospholipids into fibrin. We conclude that the inhibitory effect of surfactant incorporation into polymerizing fibrin on its susceptibility to plasmic cleavage is enhanced by SP-B and SP-C but reduced by SP-A. In the case of SP-B, increased phospholipid incorporation may underlie this finding.
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Affiliation(s)
- Philipp Markart
- Department of Internal Medicine, Justus-Liebig-University-Giessen, Klinikstrasse 36, D-35385 Giessen, Germany
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Affiliation(s)
- Jeffrey A Whitsett
- Division of Neonatology, Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH 45229-3039, USA.
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Bruni R. Focus on proteins, surfaces, et al. Am J Physiol Lung Cell Mol Physiol 2002; 283:L894-6. [PMID: 12376340 DOI: 10.1152/ajplung.00137.2002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Haczku A, Atochina EN, Tomer Y, Cao Y, Campbell C, Scanlon ST, Russo SJ, Enhorning G, Beers MF. The late asthmatic response is linked with increased surface tension and reduced surfactant protein B in mice. Am J Physiol Lung Cell Mol Physiol 2002; 283:L755-65. [PMID: 12225952 DOI: 10.1152/ajplung.00062.2002] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pulmonary surfactant dysfunction may significantly contribute to small airway obstruction during the asthmatic response, but neither its exact role nor its regulation is clear. Surfactant function and composition was studied in an Aspergillus fumigatus (Af)-induced late-phase allergic airway response in sensitized BALB/c mice. The peak of Af-induced airway hyperresponsiveness in sensitized and challenged mice 24 h after allergen provocation coincided with a significant fall in surface activity of the pulmonary surfactant. The underlying changes included time-dependent elaboration of eotaxin and IL-5 followed by eosinophil influx into the airways. The height of airway inflammation and hyperresponsiveness was preceded by release of IL-4 and marked reductions in surfactant protein (SP)-B, a hydrophobic surfactant protein responsible for maintaining low surface tension of the lining fluid of distal air spaces. Furthermore, intratracheal administration of IL-4 significantly inhibited SP-B, indicating a regulatory role of this cytokine in the surfactant biophysical changes. Thus surfactant dysfunction induced by an IL-4-driven SP-B deficiency after allergen provocation may be an important part of the late asthmatic airway response.
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Affiliation(s)
- Angela Haczku
- Pulmonary, Allergy and Critical Care Division, Department of Medicine, University of Pennsylvania Medical School, Philadelphia 19104, USA.
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Affiliation(s)
- Lawrence M Nogee
- Division of Neonatology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-3200, USA.
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Schmidt R, Steinhilber W, Ruppert C, Daum C, Grimminger F, Seeger W, Günther A. An ELISA technique for quantification of surfactant apoprotein (SP)-C in bronchoalveolar lavage fluid. Am J Respir Crit Care Med 2002; 165:470-4. [PMID: 11850338 DOI: 10.1164/ajrccm.165.4.2102080] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Pulmonary surfactant apoprotein C (SP-C) is a small, unique peptide that contributes to the reduction of alveolar surface tension. Due to the extreme hydrophobic nature of this peptide it was hitherto not possible to quantify SP-C in biological samples by immunological techniques. Using a newly developed polyclonal antibody raised against recombinant human SP-C in rabbits, we now describe an enzyme-linked immunosorbent assay (ELISA) to quantitate SP-C in bronchoalveolar lavage fluid (BALF). Solid phase binding of the hydrophobic SP-C was achieved by transfer of the standard or BALF samples (diluted in 80% isopropanol, pH 3.5) to polystyrene microtiter plates. Sequential treatment with trifluoroethanol and methanol (2x) was employed to improve antigen presentation and to minimize the influence of phospholipids. With this assay, SP-C from human, rabbit, porcine, and bovine surfactant was detectable. No cross-reactivity of the antibody to human SP-A and monomeric and dimeric SP-B was encountered. Total serum proteins did not affect ELISA signals, as evident from spiking experiments. The detection limit of the ELISA ranged below 3 ng/ml, and intra- and interassay coefficients of variation were 3.5% (n = 16) and 5.3% (n = 6), respectively. Serial dilutions of BALF showed good linearity, and excellent recovery rates were obtained upon spiking of human BALF. A mean value of 579.5 +/- 45.9 ng/ml (mean +/- SEM) SP-C was found in BALF samples of human healthy volunteers (n = 22), corresponding to 26.61 +/- 1.91 microg SP-C/mg total phospholipids (PL). SP-C levels were significantly lower in BALF of patients with acute respiratory distress syndrome (ARDS) (286.9 +/- 19.8 ng/ml [p < 0.001]; 13.92 +/- 1.93 microg SP-C/mg PL [p < 0.001], n = 48). We conclude that SP-C may be quantified with high specificity, reproducibility, and sensitivity in bronchoalveolar lavage samples by the presently described ELISA technique and that SP-C levels are significantly decreased in ARDS.
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Affiliation(s)
- Reinhold Schmidt
- Department of Internal Medicine, Justus-Liebig-University, Giessen, Germany
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Abstract
Surfactant proteins, SP-A, SP-B, SP-C and SP-D, play important roles in pulmonary surfactant function and metabolism. SP-A and SP-D, being members of the collectin family of proteins, also interact with pathogens and are involved in pulmonary host defense. Respiratory diseases are among the most common causes of death worldwide. Several life-threatening lung diseases, such as neonatal respiratory distress syndrome (RDS) and acute ROS (ARDS), are associated with impaired surfactant function. Allelic variations of the SP-A and SP-B genes have been shown to be important genetic determinants in individual susceptibility to RDS, which is a good general model for a multifactorial pulmonary disease resulting from complex interactions between several environmental and genetic factors. Because SP-A and SP-D act directly in the clearance of common lung pathogens, the genes encoding these proteins have been implicated as candidates in a few infectious diseases, including respiratory syncytial virus (RSV) infections and tuberculosis.
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Affiliation(s)
- Ritva Haataja
- Department of Paediatrics and Biocenter Oulu, University of Oulu, Finland.
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Schram V, Hall SB. Thermodynamic effects of the hydrophobic surfactant proteins on the early adsorption of pulmonary surfactant. Biophys J 2001; 81:1536-46. [PMID: 11509366 PMCID: PMC1301631 DOI: 10.1016/s0006-3495(01)75807-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
We determined the influence of the two hydrophobic proteins, SP-B and SP-C, on the thermodynamic barriers that limit adsorption of pulmonary surfactant to the air-water interface. We compared the temperature and concentration dependence of adsorption, measured by monitoring surface tension, between calf lung surfactant extract (CLSE) and the complete set of neutral and phospholipids (N&PL) without the proteins. Three stages generally characterized the various adsorption isotherms: an initial delay during which surface tension remained constant, a fall in surface tension at decreasing rates, and, for experiments that reached approximately 40 mN/m, a late acceleration of the fall in surface tension to approximately 25 mN/m. For the initial change in surface tension, the surfactant proteins accelerated adsorption for CLSE relative to N&PL by more than ten-fold, reducing the Gibbs free energy of transition (DeltaG(O)) from 119 to 112 kJ/mole. For the lipids alone in N&PL, the enthalpy of transition (DeltaH(O), 54 kJ/mole) and entropy (-T. DeltaS, 65 kJ/mole at 37 degrees C) made roughly equal contributions to DeltaG(O). The proteins in CLSE had little effect on -T. DeltaS(O) (68 kJ/mole), but lowered DeltaG(O) for CLSE by reducing DeltaH(O) (44 kJ/mole). Models of the detailed mechanisms by which the proteins facilitate adsorption must meet these thermodynamic constraints.
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Affiliation(s)
- V Schram
- Departments of Biochemistry and Molecular Biology, Medicine, and Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon 97201-3098, USA
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Haagsman HP, Diemel RV. Surfactant-associated proteins: functions and structural variation. Comp Biochem Physiol A Mol Integr Physiol 2001; 129:91-108. [PMID: 11369536 DOI: 10.1016/s1095-6433(01)00308-7] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Pulmonary surfactant is a barrier material of the lungs and has a dual role: firstly, as a true surfactant, lowering the surface tension; and secondly, participating in innate immune defence of the lung and possibly other mucosal surfaces. Surfactant is composed of approximately 90% lipids and 10% proteins. There are four surfactant-specific proteins, designated surfactant protein A (SP-A), SP-B, SP-C and SP-D. Although the sequences and post-translational modifications of SP-B and SP-C are quite conserved between mammalian species, variations exist. The hydrophilic surfactant proteins SP-A and SP-D are members of a family of collagenous carbohydrate binding proteins, known as collectins, consisting of oligomers of trimeric subunits. In view of the different roles of surfactant proteins, studies determining the structure-function relationships of surfactant proteins across the animal kingdom will be very interesting. Such studies may reveal structural elements of the proteins required for surface film dynamics as well as those required for innate immune defence. Since SP-A and SP-D are also present in extrapulmonary tissues, the hydrophobic surfactant proteins SP-B and SP-C may be the most appropriate indicators for the evolutionary origin of surfactant. SP-B is essential for air-breathing in mammals and is therefore largely conserved. Yet, because of its unique structure and its localization in the lung but not in extrapulmonary tissues, SP-C may be the most important indicator for the evolutionary origin of surfactant.
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Affiliation(s)
- H P Haagsman
- Department of Biochemistry, Cell Biology and Histology and Graduate School of Animal Health, Utrecht University, P.O. Box 80175, 3508 TD, Utrecht, The Netherlands.
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Abstract
SP-B is the only surfactant-associated protein absolutely required for postnatal lung function and survival. Complete deficiency of SP-B in mice and humans results in lethal, neonatal respiratory distress syndrome and is characterized by a virtual absence of lung compliance, highly disorganized lamellar bodies, and greatly diminished levels of SP-C mature peptide; in contrast, lung structure and function in SP-C null mice is normal. This review attempts to integrate recent findings in humans and transgenic mice with the results of in vitro studies to provide a better understanding of the functions of SP-B and SP-C and the structural basis for their actions.
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Affiliation(s)
- T E Weaver
- Division of Pulmonary Biology, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA.
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50
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Abstract
Lung surfactant covers and stabilizes a large, delicate surface at the interface between the host and the environment. The surfactant system is placed at risk by a number of environmental challenges such as inflammation, infection, or oxidant stress, and perhaps not surprisingly, it demonstrates adaptive changes in metabolism in response to alterations in the alveolar microenvironment. Recent experiments have shown that certain components of the surfactant system are active participants in the regulation of the alveolar response to a wide variety of environmental challenges. These components are capable not only of maintaining a low interfacial surface tension but also of amplifying or dampening inflammatory responses. These observations suggest that regulatory molecules are capable of both sensing the environment of the alveolus and providing feedback to the cells regulating surfactant synthesis, secretion, alveolar conversion, and clearance. In this review we examine the evidence from in vitro systems and gene-targeted mice that two surfactant-associated collectins (SP-A and SP-D) may serve in these roles and help modify surfactant homeostasis as part of a coordinated host response to environmental challenges.
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Affiliation(s)
- S Hawgood
- Cardiovascular Research Institute and Department of Pediatrics, University of California San Francisco, San Francisco, California 94143-0734, USA.
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