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Miller ML, Porollo A, Wert S. Ultrastructure of Highly Ordered Granules in Alveolar Type II Cells in Several Species. Anat Rec (Hoboken) 2018; 301:1290-1302. [PMID: 29544026 DOI: 10.1002/ar.23805] [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: 04/21/2017] [Revised: 11/30/2017] [Accepted: 02/02/2018] [Indexed: 01/26/2023]
Abstract
Alveolar Type II cells from seven mammalian species were examined for a protein in the rough endoplasmic reticulum (RER), which showed a multilayered, repeating motif. Each motif, 100 nm in width, comprised two parallel outer dense layers, a less dense central layer, and often 1-3 faint layers on either side of the latter. Outer layers showed periodicities at 3-4 densities/100 nm of width, while layers on either side of the central layer showed 5-7 densities/100 nm of width. RER membranes were ribosome-free when parallel to these layers, but showed four ribosomes per motif at the growing ends: one ribosome at each outer dense layer, and one on either side of the less dense central layer. Granules appeared as single or as multiple motifs, stacked, curved, folded, or branching together within the same RER profile. Hexagons of around 30 nm in diameter with central densities were seen in tangential cuts of outer dense layers. Granule incidence varied: guinea pig > ferret > dog. Possible homologous structures occurred in rabbit and cat, but not in rat or mouse. Surfactant protein A (SP-A), a C-type lectin produced in Type II cells, forms trimers and bouquet-like 18-mer and can oligomerize further. Two pairs of SP-A 18-mers with carbohydrate recognition domains pointing inwardly and outwardly, stacked vertically as a column of four molecules, then repeated side by side in rows, approximated the size and layering patterns observed in these granules. Sequence analyses of SP-A from these species showed phylogenetic distances consistent with the observed occurrence and frequency of patterned granules. Anat Rec, 301:1290-1302, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Marian L Miller
- Department of Environmental Health, University of Cincinnati, College of Medicine, Cincinnati, Ohio
| | - Aleksey Porollo
- Department of Pediatrics, University of Cincinnati, College of Medicine, Cincinnati, Ohio.,Center for Autoimmune Genomics and Etiology, University of Cincinnati, College of Medicine, Cincinnati, Ohio
| | - Susan Wert
- Department of Pediatrics, University of Cincinnati, College of Medicine, Cincinnati, Ohio.,Division of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
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2
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Yang MY, Hilton MB, Seaman S, Haines DC, Nagashima K, Burks CM, Tessarollo L, Ivanova PT, Brown HA, Umstead TM, Floros J, Chroneos ZC, St. Croix B. Essential regulation of lung surfactant homeostasis by the orphan G protein-coupled receptor GPR116. Cell Rep 2013; 3:1457-64. [PMID: 23684610 PMCID: PMC3695742 DOI: 10.1016/j.celrep.2013.04.019] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 04/08/2013] [Accepted: 04/19/2013] [Indexed: 11/22/2022] Open
Abstract
GPR116 is an orphan seven-pass transmembrane receptor whose function has been unclear. Global disruption of the Gpr116 gene in mice revealed an unexpected, critical role for this receptor in lung surfactant homeostasis, resulting in progressive accumulation of surfactant lipids and proteins in the alveolar space, labored breathing, and a reduced lifespan. GPR116 expression analysis, bone marrow transplantation studies, and characterization of conditional knockout mice revealed that GPR116 expression in ATII cells is required for maintaining normal surfactant levels. Aberrant packaging of surfactant proteins with lipids in the Gpr116 mutant mice resulted in compromised surfactant structure, function, uptake, and processing. Thus, GPR116 plays an indispensable role in lung surfactant homeostasis with important ramifications for the understanding and treatment of lung surfactant disorders.
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Affiliation(s)
- Mi Young Yang
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program (MCGP), National Cancer Institute (NCI), NIH, Frederick, MD, 21702, USA
| | - Mary Beth Hilton
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program (MCGP), National Cancer Institute (NCI), NIH, Frederick, MD, 21702, USA
- Basic Research Program, SAIC, Frederick National Laboratory for Cancer Research (FNLCR), NCI, NIH, Frederick, MD 21702, USA
| | - Steven Seaman
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program (MCGP), National Cancer Institute (NCI), NIH, Frederick, MD, 21702, USA
| | - Diana C. Haines
- Veterinary Pathology Section, Pathology/Histotechnology Laboratory, SAIC, FNLCR, NCI, Frederick, MD, 21702, USA
| | - Kunio Nagashima
- Electron Microscopy Laboratory, Advanced Technology Program, SAIC, FNLCR, NCI, Frederick, MD, 21702, USA
| | - Christina M. Burks
- Electron Microscopy Laboratory, Advanced Technology Program, SAIC, FNLCR, NCI, Frederick, MD, 21702, USA
| | - Lino Tessarollo
- Neural Development Section, MCGP, NCI, NIH, Frederick, MD 21702, USA
| | - Pavlina T. Ivanova
- Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - H. Alex Brown
- Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Todd M. Umstead
- Department of Pediatrics (CHILD), The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA, 17033, USA
| | - Joanna Floros
- Department of Pediatrics (CHILD), The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA, 17033, USA
- Department of Obstetrics and Gynecology, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA, 17033, USA
| | - Zissis C. Chroneos
- Department of Pediatrics (CHILD), The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA, 17033, USA
| | - Brad St. Croix
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program (MCGP), National Cancer Institute (NCI), NIH, Frederick, MD, 21702, USA
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Prata LO, Oliveira FMS, Ribeiro TMS, Almeida PWM, Cardoso JA, Rodrigues-Machado MDG, Caliari MV. Exercise attenuates pulmonary injury in mice with bleomycin-induced pulmonary fibrosis. Exp Biol Med (Maywood) 2012; 237:873-83. [PMID: 22903133 DOI: 10.1258/ebm.2012.011334] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human idiopathic pulmonary fibrosis (IPF) is a disease with unknown etiology and poor prognosis in which patients present a decrease in functional exercise tolerance and quality of life. At present, no treatment which can improve the prognosis of this disease is available. Many biomarkers of pulmonary fibrosis have been studied, and surfactant protein A (SP-A) expression is considered a specific marker of lung disease. This study aimed to investigate the influence of exercise training on exercise endurance capacity and murine-lung lesions induced by bleomycin (BLM). Thirty-four male Balb/c mice were subdivided into four groups: control sedentary (C-SED), bleomycin-treated sedentary (BLM-SED), control exercised (C-EXE) and bleomycin-treated exercised (BLM-EXE). Mice received 6.25 U/kg of BLM or saline via intratracheal instillation. After adaptation in a swimming pool, the animals started training one hour per day, with 60% of maximum load obtained in exercise endurance capacity assessment, five days/week for four weeks. The lungs were collected 48 h after the second endurance capacity assessment, fixed in buffered formalin and embedded in paraffin. Sections were analyzed using histochemical and immunohistochemical reactions for digital morphometry of pulmonary fibrosis, type I collagen, SP-A and type II pneumocytes (PII). The exercise endurance capacity of groups C-EXE (9.20 ± 0.81 min) and BLM-EXE (8.40 ± 0.82 min) increased significantly when compared with groups C-SED (5.84 ± 0.4 min) and BLM-SED (5.67 ± 0.60 min). The amounts of connective tissue, type I collagen, PII and SP-A increased significantly in the BLM-SED group. Exercise training significantly attenuated this response as observed in the BLM-EXE group. The present study shows that exercise training can prevent the decline of exercise endurance capacity and attenuate the progression of IPF.
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Affiliation(s)
- Luana O Prata
- Programa de Pós-Graduação em Patologia, Instituto de Ciê ncias Biológicas da Universidade Federal de Minas Gerais, Minas Gerais, Brazil
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Surfactant protein A modulates the lipopolysaccharide-induced inflammatory response related to preterm birth. Cytokine 2011; 56:442-9. [PMID: 21865055 DOI: 10.1016/j.cyto.2011.07.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 07/07/2011] [Accepted: 07/25/2011] [Indexed: 11/20/2022]
Abstract
Surfactant protein A (SP-A) functions in homeostasis of lung surfactant and in innate immunity. SP-A is secreted by the fetal lung into amniotic fluid. Additionally it has been detected in gestational tissues. We propose that SP-A influences intrauterine inflammation that is commonly associated with preterm birth, the main underlying cause of neonatal mortality and morbidity. We used our previously established mouse model of LPS-induced preterm birth of live-born pups to investigate the role of SP-A in preterm birth. Mice overexpressing rat SP-A (rSP-A) under the control of human SP-C promoter were used. Cytokine concentrations in maternal and fetal serum and in amniotic fluid and mRNA levels of several inflammatory mediators in lungs and in intrauterine tissues were quantified using Cytometric Bead Array and RNase Protection Assay, respectively. Higher levels of SP-A mRNA were observed in fetal lungs and intrauterine tissues of rSP-A mice compared with wild-type. Using Western blot we detected excess of SP-A protein in fetal lung and in amniotic fluid of rSP-A animals. Despite some differences in the basal levels of TNF-α and IL-10 between rSP-A and wild-type animals, there were no differences in the duration of pregnancy. However, the levels of TNF-α, IL-10 and some other inflammatory mediators in intrauterine tissues and in amniotic fluid differed significantly between the mouse lines after maternal LPS given at 17dpc. We conclude that SP-A modulates the levels of intrauterine inflammatory mediators involved in preterm birth and may contribute to inflammatory processes related to spontaneous preterm labor.
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Forbes LR, Haczku A. SP-D and regulation of the pulmonary innate immune system in allergic airway changes. Clin Exp Allergy 2010; 40:547-62. [PMID: 20447075 DOI: 10.1111/j.1365-2222.2010.03483.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The airway mucosal surfaces are constantly exposed to inhaled particles that can be potentially toxic, infectious or allergenic and should elicit inflammatory changes. The proximal and distal air spaces, however, are normally infection and inflammation free due to a specialized interplay between cellular and molecular components of the pulmonary innate immune system. Surfactant protein D (SP-D) is an epithelial-cell-derived immune modulator that belongs to the small family of structurally related Ca(2+)-dependent C-type collagen-like lectins. While collectins can be detected in mucosal surfaces of various organs, SP-A and SP-D (the 'lung collectins') are constitutively expressed in the lung at high concentrations. Both proteins are considered important players of the pulmonary immune responses. Under normal conditions however, SP-A-/- mice display no pathological features in the lung. SP-D-/- mice, on the other hand, show chronic inflammatory alterations indicating a special importance of this molecule in regulating immune homeostasis and the function of the innate immune cells. Recent studies in our laboratory and others implied significant associations between changes in SP-D levels and the presence of airway inflammation both in animal models and patients raising a potential usefulness of this molecule as a disease biomarker. Research on wild-type and mutant recombinant molecules in vivo and in vitro showed that SP-D binds carbohydrates, lipids and nucleic acids with a broad spectrum specificity and initiates phagocytosis of inhaled pathogens as well as apoptotic cells. Investigations on gene-deficient and conditional over expressor mice in addition, provided evidence that SP-D directly modulates macrophage and dendritic cell function as well as T cell-dependent inflammatory events. Thus, SP-D has a unique, dual functional capacity to induce pathogen elimination on the one hand and control of pro-inflammatory mechanisms on the other, suggesting a potential suitability for therapeutic prevention and treatment of chronic airway inflammation without compromising the host defence function of the airways. This paper will review recent findings on the mechanisms of immune-protective function of SP-D in the lung.
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Affiliation(s)
- L R Forbes
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Casals C. Role of Surfactant Protein a (SP-A)/Lipid Interactions for SP-A Functions in the Lung. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/15513810109168821] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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7
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Wang G, Guo X, Diangelo S, Thomas NJ, Floros J. Humanized SFTPA1 and SFTPA2 transgenic mice reveal functional divergence of SP-A1 and SP-A2: formation of tubular myelin in vivo requires both gene products. J Biol Chem 2010; 285:11998-2010. [PMID: 20048345 DOI: 10.1074/jbc.m109.046243] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Surfactant protein A (SP-A) plays a role in lung innate immunity and surfactant-related functions. Two functional genes, SP-A1 (SFTPA1) and SP-A2 (SFTPA2), are present in humans and primates (rodents have one gene). Single gene SP-A1 or SP-A2 proteins expressed in vitro are functional. To study their role in vivo, we generated humanized transgenic (hTG) C57BL/6 mice, SP-A1(6A(4)) and SP-A2(1A(3)). The SP-A cDNA in experimental constructs was driven by the 3.7-kb SP-C promoter. Positive hTG mice were bred with SP-A knock-out mice to generate F8 offspring for study. Epithelial alveolar type II cells were SP-A-positive, and Clara cells were negative by immunohistochemistry in hTG mice. The levels of SP-A in lungs of two hTG lines used were comparable with those in human lungs. Southern blot analysis indicated that two cDNA copies of either SP-A1(6A(4)) or SP-A2(1A(3)) were integrated as a concatemer into the genome of each of the two hTG lines. Electron microscopy analysis revealed that hTG mice with a single SP-A1(6A(4)) or SP-A2(1A(3)) gene product lacked tubular myelin (TM), but hTG mice carrying both had TM. Furthermore, TM was observed in human bronchoalveolar lavage fluid only if both SP-A1 and SP-A2 gene products were present and not in those containing primarily (>99.7%) either SP-A1 or SP-A2 gene products. In vivo rescue study confirmed that TM can only be restored after administering exogenous SP-A containing both SP-A1 and SP-A2 into the lungs of SP-A knock-out mice. These observations indicate that SP-A1 and SP-A2 diverged functionally at least in terms of TM formation.
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Affiliation(s)
- Guirong Wang
- Penn State Center for Host Defense, Inflammation, and Lung Disease Research, Department of Pediatrics, Penn State HersheyCollege ofMedicine, Pennsylvania State University, Hershey, Pennsylvania 17033, USA
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8
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Haczku A. Protective role of the lung collectins surfactant protein A and surfactant protein D in airway inflammation. J Allergy Clin Immunol 2008; 122:861-79; quiz 880-1. [PMID: 19000577 DOI: 10.1016/j.jaci.2008.10.014] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2008] [Revised: 10/13/2008] [Accepted: 10/13/2008] [Indexed: 12/30/2022]
Abstract
The acute inflammatory airway response is characterized by a time-dependent onset followed by active resolution. Emerging evidence suggests that epithelial cells of the proximal and distal air spaces release host defense mediators that can facilitate both the initiation and the resolution part of inflammatory airway changes. These molecules, also known as the hydrophilic surfactant proteins (surfactant protein [SP]-A and SP-D) belong to the class of collagenous lectins (collectins). The collectins are a small family of soluble pattern recognition receptors containing collagenous regions and C-type lectin domains. SP-A and SP-D are most abundant in the lung. Because of their structural uniqueness, specific localization, and functional versatility, lung collectins are important players of the pulmonary immune responses. Recent studies in our laboratory and others indicated significant associations of lung collectin levels with acute and chronic airway inflammation in both animal models and patients, suggesting the usefulness of these molecules as disease biomarkers. Research on wild-type and mutant recombinant molecules in vivo and in vitro showed that SP-A and SP-D bind carbohydrates, lipids, and nucleic acids with a broad-spectrum specificity and initiate phagocytosis of inhaled pathogens as well as apoptotic cells. Investigations on gene-deficient and conditional overexpresser mice indicated that lung collectins also directly modulate innate immune cell function and T-cell-dependent inflammatory events. Thus, these molecules have a unique, dual-function capacity to induce pathogen elimination and control proinflammatory mechanisms, suggesting a potential suitability for therapeutic prevention and treatment of chronic airway inflammation. This article reviews evidence supporting that the lung collectins play an immune-protective role and are essential for maintenance of the immunologic homeostasis in the lung.
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Affiliation(s)
- Angela Haczku
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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Chaiworapongsa T, Hong JS, Hull WM, Kim CJ, Gomez R, Mazor M, Romero R, Whitsett JA. The concentration of surfactant protein-A in amniotic fluid decreases in spontaneous human parturition at term. J Matern Fetal Neonatal Med 2008; 21:652-9. [PMID: 18828058 PMCID: PMC3418916 DOI: 10.1080/14767050802215193] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVE The fetus is thought to play a central role in the onset of labor. Pulmonary surfactant protein (SP)-A, secreted by the maturing fetal lung, has been implicated in the mechanisms initiating parturition in mice. The present study was conducted to determine whether amniotic fluid concentrations of SP-A and SP-B change during human parturition. STUDY DESIGN Amniotic fluid SP-A and SP-B concentrations were measured with a sensitive and specific ELISA in the following groups of pregnant women: (1) mid-trimester of pregnancy, between 15 and 18 weeks of gestation (n = 29), (2) term pregnancy not in labor (n = 28), and (3) term pregnancy in spontaneous labor (n = 26). Non-parametric statistics were used for analysis. RESULTS SP-A was detected in all amniotic fluid samples. SP-B was detected in 24.1% (7/29) of mid-trimester samples and in all samples at term. The median amniotic fluid concentrations of SP-A and SP-B were significantly higher in women at term than in women in the mid-trimester (SP-A term no labor: median 5.6 microg/mL, range 2.2-15.2 microg/mL vs. mid-trimester: median 1.64 microg/mL, range 0.1-4.7 microg/mL, and SP-B term no labor: median 0.54 microg/mL, range 0.17-1.99 microg/mL vs. mid-trimester: median 0 microg/mL, range 0-0.35 microg/mL; both p < 0.001). The median amniotic fluid SP-A concentration in women at term in labor was significantly lower than that in women at term not in labor (term in labor: median 2.7 microg/mL, range 1.2-10.1 microg/mL vs. term no labor: median 5.6 microg/mL, range 2.2-15.2 microg/mL; p < 0.001). There was no significant difference in the median amniotic fluid SP-B concentrations between women in labor and those not in labor (term in labor: median 0.47 microg/mL, range 0.04-1.32 microg/mL vs. term no labor: median 0.54 microg/mL, range 0.17-1.99 microg/mL; p = 0.2). CONCLUSION The amniotic fluid concentration of SP-A decreases in spontaneous human parturition at term.
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Affiliation(s)
- Tinnakorn Chaiworapongsa
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland and Detroit, Michigan, USA
- Wayne State University School of Medicine, Department of Obstetrics and Gynecology, Detroit, Michigan, USA
| | - Joon-Seok Hong
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland and Detroit, Michigan, USA
| | - William M. Hull
- Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Chong Jai Kim
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland and Detroit, Michigan, USA
- Wayne State University School of Medicine, Department of Pathology, Detroit, Michigan, USA
| | - Ricardo Gomez
- Center for Perinatal Diagnosis and Research (CEDIP), Sótero del Río Hospital, P. Universidad Católica de Chile, Puente Alto, Chile
| | - Moshe Mazor
- Department of Obstetrics and Gynecology, Soroka Medical Center, Ben Gurion University, Beer Sheva, Israel
| | - Roberto Romero
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland and Detroit, Michigan, USA
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, USA
| | - Jeffrey A. Whitsett
- Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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Fehrenbach H, Fehrenbach A, Dietzel E, Tschernig T, Krug N, Grau V, Hohlfeld JM. Effects of keratinocyte growth factor on intra-alveolar surfactant fixed in situ: Quantitative ultrastructural and immunoelectron microscopic analysis. Anat Rec (Hoboken) 2007; 290:974-80. [PMID: 17516448 DOI: 10.1002/ar.20549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Quantitative (immuno) transmission electron microscopy using design-based stereology was performed on specimens collected by means of systematic uniform random sampling of rat lungs, which were fixed by vascular perfusion to stabilize intra-alveolar surfactant in situ. This procedure ensures that the data recorded are representative of the whole organ. Ultrathin sections of specimens embedded at low temperature in Lowicryl HM20 were labeled by indirect immuno-gold staining for surfactant protein A. We observed that, 3 days after treatment of lungs in vivo with truncated keratinocyte growth factor (DeltaN23-KGF), a potent mitogen of alveolar epithelial type II cells, surfactant protein A associated with the tubular myelin fraction of intra-alveolar surfactant was increased by 47% in comparison with buffer-treated control lungs. Despite the marked type II cell hyperplasia, the relative amount of ultrastructural surfactant subtypes was not significantly affected. Because surfactant protein A reduces the sensitivity to inhibition of the biophysical activity of surfactant by exudating plasma proteins, we propose that pretreatment of lungs with DeltaN23-KGF ameliorates adverse effects observed in acute lung injury following, for example, ischemia and reperfusion.
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Affiliation(s)
- Heinz Fehrenbach
- Clinical Research Group "Chronic Airway Diseases", Clinic of Internal Medicine (Respiratory Medicine), Philipps-University Marburg, Baldingerstrasse, Marburg Germany.
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Zhang L, Ikegami M, Korfhagen TR, McCormack FX, Yoshida M, Senior RM, Shipley JM, Shapiro SD, Whitsett JA. Neither SP-A nor NH2-terminal domains of SP-A can substitute for SP-D in regulation of alveolar homeostasis. Am J Physiol Lung Cell Mol Physiol 2006; 291:L181-90. [PMID: 16500946 DOI: 10.1152/ajplung.00015.2006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Surfactant proteins (SP)-A and -D are members of the collectin family of host defense proteins that share four distinct structural domains: NH2-terminal oligomerization, collagenous, neck, and carbohydrate recognition (CRD). To determine the specificity of the functions of these domains, the SFTPC promoter was used to express 1) full-length rat (r) Sftpa; 2) NH2- rSftpa/d, consisting of NH2-terminal and collagenous domains of SP-A with neck domain and CRD of SP-D; and 3) rSftpd/a, consisting of NH2-terminal and collagenous domains of SP-D with neck domain and CRD of SP-A, in Sftpd−/−mice. Increased expression of SP-A in Sftpd−/−mice did not correct the increased pulmonary saturated phosphatidylcholine levels, emphysema, or foamy alveolar macrophage and lymphocyte infiltrations characteristic of Sftpd−/−mice, indicating that the decreased SP-A level noted in Sftpd−/−mice does not account for the observed pulmonary abnormalities. The chimeric protein NH2-rSftpa/d was expressed and detected in the airways of transgenic mice, migrating as an SP-A-like oligomer that associated with large aggregate surfactant in a manner similar to that of SP-A rather than SP-D. NH2-rSftpa/d did not correct emphysema, foamy macrophage and lymphocyte infiltration, or the increased lipid accumulations characteristic of Sftpd−/−mice. Thus oligomerization and surfactant lipid association of SP-D requires its NH2-terminal and collagenous domains, which are needed for SP-D-dependent regulation of surfactant homeostasis in vivo. Attempts to express rSftpd/a fusion protein in vivo were unsuccessful. Mmp9−/−/Sftpd−/−and Mmp12−/−/Sftpd−/−mice developed air space enlargement similar to Sftpd−/−mice, supporting the concept that the increased expression of each metalloproteinase seen in Sftpd−/−lungs is not the major cause of emphysema.
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Affiliation(s)
- Liqian Zhang
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, OH 45229, USA
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12
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Linke M, Ashbaugh A, Koch J, Tanaka R, Walzer P. Efficient resolution of Pneumocystis murina infection in surfactant protein A-deficient mice following withdrawal of corticosteroid-induced immunosuppression. J Med Microbiol 2006; 55:143-147. [PMID: 16434705 DOI: 10.1099/jmm.0.46190-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Following withdrawal of immunosuppression, surfactant protein A (SP-A)-deficient and wild-type mice cleared Pneumocystis murina infection in a similar manner, but exhibited significant differences in lymphocyte populations, interleukin (IL)-6 levels and chemokine expression levels. A higher percentage of lymphocytes were detected in lung lavage fluid from SP-A-deficient mice, but more CD4+ T cells were isolated from lung tissue of wild-type mice. Higher concentrations of IL-6 were detected in lavage fluid and enhanced expression of lymphotactin and RANTES were detected in the lungs of wild-type mice. Equal levels of surfactant protein D were detected in SP-A-deficient and wild-type mice and no differences were detected in markers of lung injury between the two strains of mice. Thus, SP-A does not enhance organism clearance, but does modulate the host immune response during resolution of P. murina infection.
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Affiliation(s)
- Michael Linke
- University of Cincinnati College of Medicine, Department of Internal Medicine, Division of Infectious Diseases, 231 Bethesda, Cincinnati, OH 45221, USA
- Department of Veterans Affairs Medical Center, Research Service, 3200 Vine St, Cincinnati, OH 45220, USA
| | - Alan Ashbaugh
- University of Cincinnati College of Medicine, Department of Internal Medicine, Division of Infectious Diseases, 231 Bethesda, Cincinnati, OH 45221, USA
| | - Judith Koch
- University of Cincinnati College of Medicine, Department of Internal Medicine, Division of Infectious Diseases, 231 Bethesda, Cincinnati, OH 45221, USA
| | - Reiko Tanaka
- University of Cincinnati College of Medicine, Department of Internal Medicine, Division of Infectious Diseases, 231 Bethesda, Cincinnati, OH 45221, USA
| | - Peter Walzer
- University of Cincinnati College of Medicine, Department of Internal Medicine, Division of Infectious Diseases, 231 Bethesda, Cincinnati, OH 45221, USA
- Department of Veterans Affairs Medical Center, Research Service, 3200 Vine St, Cincinnati, OH 45220, USA
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Starosta V, Rietschel E, Paul K, Baumann U, Griese M. Oxidative Changes of Bronchoalveolar Proteins in Cystic Fibrosis. Chest 2006; 129:431-437. [PMID: 16478863 DOI: 10.1378/chest.129.2.431] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Chronic bacterial infection and severe, polymorphonuclear neutrophil-dominated endobronchial inflammation are characteristic hallmarks of cystic fibrosis (CF) lung disease. The free radicals generated can be deleterious for structure and function of many proteins. The goal of this study was to investigate the degree of oxidation of pulmonary epithelial lining fluid proteins. BAL fluid (BALF) from 55 children with CF and from 11 patients in a control group were investigated by dot-blot assay for content and by two-dimensional electrophoresis and Western blotting for the pattern of distribution of oxidized proteins. The highest level of oxidative stress, as assessed by the level of protein carbonyls, was found in patients with FEV1 < 80% of predicted or with highly elevated neutrophil counts. Compared to control subjects without lung disease, CF patients with normal lung function and CF patients with a normal neutrophil count in their BALF had significantly higher protein carbonyl levels. The extent of protein oxidation was directly related to the neutrophil granulocyte count and inversely to lung function. Our data support the hypothesis that oxidative damage of pulmonary proteins during chronic and excessive neutrophilic endobronchial inflammation may contribute to the decline of lung function in CF patients.
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Affiliation(s)
- Vitaliy Starosta
- Lung Research Group, Children's Hospital of Ludwig Maximilians University, Munich
| | - Ernst Rietschel
- Department of Pediatric Pneumology and Allergology, Childrens' Hospital University of Cologne, Cologne
| | - Karl Paul
- Department of Pediatric Pneumology and Immunology, Charité, Humboldt-University, Berlin
| | - Ulrich Baumann
- Department of Pediatric Pulmonology and Neonatology, Hannover Medical School, Hannover, Germany
| | - Matthias Griese
- Lung Research Group, Children's Hospital of Ludwig Maximilians University, Munich.
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14
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Haczku A. Role and regulation of lung collectins in allergic airway sensitization. Pharmacol Ther 2005; 110:14-34. [PMID: 16226313 DOI: 10.1016/j.pharmthera.2005.08.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Accepted: 08/23/2005] [Indexed: 12/21/2022]
Abstract
Inhalation of allergens in atopic patients results in a characteristic inflammatory response while in normal, healthy individuals it elicits no symptoms. The mechanisms by which the pulmonary immune system accomplishes elimination of inhaled particles and suppression of the ensuing inflammatory response are poorly understood. Based on their structural uniqueness, specific localization and functional versatility the hydrophilic surfactant proteins [surfactant protein (SP)-A and SP-D] are important candidate regulators of these processes. Recent studies in our laboratory and others indicated significant changes in levels of these molecules during the asthmatic response in animal models as well as in asthmatic patients. Because of their capability to directly inhibit T-cell activation and T-cell-dependent allergic inflammatory events, SP-A and SP-D may be significant contributors to the local control of T-helper (Th)2-type inflammation in the airways. This review will discuss their relevant structural-functional features and recent evidence supporting the hypothesis that SP-A and SP-D have a role in regulation of allergic airway sensitization.
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Affiliation(s)
- Angela Haczku
- Pulmonary, Allergy and Critical Care Division, Department of Medicine, University of Pennsylvania School of Medicine, 421 Curie Boulevard, BRB II/III #840, Philadelphia, 19104-6061, USA.
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15
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Cogo PE, Toffolo GM, Gucciardi A, Benetazzo A, Cobelli C, Carnielli VP. Surfactant disaturated phosphatidylcholine kinetics in infants with bronchopulmonary dysplasia measured with stable isotopes and a two-compartment model. J Appl Physiol (1985) 2005; 99:323-9. [PMID: 15774699 DOI: 10.1152/japplphysiol.01423.2004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We previously found a shorter surfactant disaturated phosphatidylcholine palmitate (DSPC-PA) half-life in infants with bronchopulmonary dysplasia (BPD) by using a single stable isotope tracer and simple formulas based on a one-exponential fit of the final portion of the enrichment decay curve. The aim of this study was to apply noncompartmental and compartmental analysis on the entire enrichment decay curve of DSPC-PA and to compare the kinetic data with our previous results. We analyzed 10 preterm newborns with BPD (gestational age 26 ± 0.6 wk, weight 777 ± 199 g) and 6 controls (gestational age 26 ± 1.4 wk, weight 787 ± 259 g). All took part in our previous study. Endotracheal13C-labeled dipalmitoyl phosphatidylcholine was administered, and the13C-enrichment of surfactant DSPC-PA was measured from serial tracheal aspirates by gas chromatography-mass spectrometry. Noncompartmental and compartmental models were numerically identified from the tracer-to-tracee ratio and kinetic parameters related to the accessible (pool accessible to sampling, likely to be the lung alveolar pool) and to the nonaccessible pools (pools not accessible to samplings, likely to be the intracellular storage pool) were estimated in the two study groups. Comparison was performed by Mann-Whitney test. A two-compartment model provided the most reliable assessment of DSPC-PA kinetics. In BPD vs. controls, mean ± SE residence time of DSPC-PA in the accessible was 17.5 ± 2.6 vs. 32.2 ± 6.4 h ( P < 0.05), whereas it was 49.7 ± 3.5 vs. 54.4 ± 3.9 h (NS, not significant) in the nonaccessible pool; DSPC-PA recycling was 0.26 ± 0.05 vs. 0.43 ± 0.04% (NS), respectively. A two-compartment model of surfactant DSPC-PA kinetics allowed a thorough assessment of DSPC-PA kinetics, including masses, synthesis, and fluxes between pools. The most important findings of this study are that in BPD infants DSPC-PA loss from the alveolar pool was higher and recycling through the intracellular pool lower than in controls.
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Affiliation(s)
- Paola E Cogo
- Dept. of Pediatrics, University of Padova, Via Giustiniani 3, 35128 Padova, Italy.
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16
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Fehrenbach H, Tews S, Fehrenbach A, Ochs M, Wittwer T, Wahlers T, Richter J. Improved lung preservation relates to an increase in tubular myelin-associated surfactant protein A. Respir Res 2005; 6:60. [PMID: 15969762 PMCID: PMC1187923 DOI: 10.1186/1465-9921-6-60] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Accepted: 06/21/2005] [Indexed: 12/15/2022] Open
Abstract
Background Declining levels of surfactant protein A (SP-A) after lung transplantation are suggested to indicate progression of ischemia/reperfusion (IR) injury. We hypothesized that the previously described preservation-dependent improvement of alveolar surfactant integrity after IR was associated with alterations in intraalveolar SP-A levels. Methods Using immuno electron microscopy and design-based stereology, amount and distribution of SP-A, and of intracellular surfactant phospholipids (lamellar bodies) as well as infiltration by polymorphonuclear leukocytes (PMNs) and alveolar macrophages were evaluated in rat lungs after IR and preservation with EuroCollins or Celsior. Results After IR, labelling of tubular myelin for intraalveolar SP-A was significantly increased. In lungs preserved with EuroCollins, the total amount of intracellular surfactant phospholipid was reduced, and infiltration by PMNs and alveolar macrophages was significantly increased. With Celsior no changes in infiltration or intracellular surfactant phospholipid amount occurred. Here, an increase in the number of lamellar bodies per cell was associated with a shift towards smaller lamellar bodies. This accounts for preservation-dependent changes in the balance between surfactant phospholipid secretion and synthesis as well as in inflammatory cell infiltration. Conclusion We suggest that enhanced release of surfactant phospholipids and SP-A represents an early protective response that compensates in part for the inactivation of intraalveolar surfactant in the early phase of IR injury. This beneficial effect can be supported by adequate lung preservation, as e.g. with Celsior, maintaining surfactant integrity and reducing inflammation, either directly (via antioxidants) or indirectly (via improved surfactant integrity).
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Affiliation(s)
- Heinz Fehrenbach
- Clinical Research Group "Chronic Airway Diseases", Department of Internal Medicine (Respiratory Medicine), Philipps-University, Baldingerstrasse, D-35043 Marburg, Germany
| | - Sebastian Tews
- Division of Electron Microscopy, Centre of Anatomy, University of Göttingen, Kreuzbergring 36, D-37075 Göttingen, Germany
| | - Antonia Fehrenbach
- Division of Electron Microscopy, Centre of Anatomy, University of Göttingen, Kreuzbergring 36, D-37075 Göttingen, Germany
- Clinical Research Group "Chronic Airway Diseases", Department of Internal Medicine (Respiratory Medicine), Philipps-University, Baldingerstrasse, D-35043 Marburg, Germany
| | - Matthias Ochs
- Division of Electron Microscopy, Centre of Anatomy, University of Göttingen, Kreuzbergring 36, D-37075 Göttingen, Germany
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH-3000 Bern 9, Switzerland
| | - Thorsten Wittwer
- Department of Cardiothoracic and Vascular Surgery, Friedrich Schiller University Jena, Bachstrasse 18, D-07740 Jena, Germany
| | - Thorsten Wahlers
- Department of Cardiothoracic and Vascular Surgery, Friedrich Schiller University Jena, Bachstrasse 18, D-07740 Jena, Germany
| | - Joachim Richter
- Division of Electron Microscopy, Centre of Anatomy, University of Göttingen, Kreuzbergring 36, D-37075 Göttingen, Germany
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17
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Casals C, García-Verdugo I. Molecular and Functional Properties of Surfactant Protein A. LUNG BIOLOGY IN HEALTH AND DISEASE 2005. [DOI: 10.1201/b14169-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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18
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Linke M, Ashbaugh A, Koch J, Tanaka R, Walzer P. Surfactant protein A limits Pneumocystis murina infection in immunosuppressed C3H/HeN mice and modulates host response during infection. Microbes Infect 2005; 7:748-59. [PMID: 15857803 DOI: 10.1016/j.micinf.2005.01.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2004] [Revised: 01/19/2005] [Accepted: 01/26/2005] [Indexed: 12/31/2022]
Abstract
The development of Pneumocystis murina pneumonia and host response were characterized over time and at different levels of infection in corticosteroid immunosuppressed surfactant protein A (SP-A) knockout and wild-type (WT) mice. Infection increased over time in both strains of mice; however, significantly more cyst forms were detected in the knockout mice at intermediate and late stages of infection. In mice with heavy infections, TNF-alpha and IFN-gamma protein concentrations were significantly higher in pulmonary lavage fluid from knockout mice. There was a significant positive correlation between TNF-alpha and IFN-gamma concentrations and the level of infection in knockout mice, but not in WT mice. No significant differences were detected in IL-1 levels between the two strains of mice at any of the time points or at any level of infection. At heavier infection levels, significantly more MIP-2 protein was detected in the lungs of knockout mice, but a significant positive correlation between MIP-2 concentrations and the infection level was detected in both groups of mice. At the intermediate stage of infection, a significantly higher percentage of neutrophils was detected in the lungs of knockout mice than in WT mice. There was no difference in SP-D levels between WT and KO mice with identical levels of infection. These data support a protective role for SP-A in host defense against Pneumocystis and suggest that the effects of SP-A on the host response vary based on the intensity of the infection.
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Affiliation(s)
- Michael Linke
- Department of Veterans Affairs Medical Center, Research Service, 3200 Vine Street, Cincinnati, OH 45220, USA.
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19
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Condon JC, Jeyasuria P, Faust JM, Mendelson CR. Surfactant protein secreted by the maturing mouse fetal lung acts as a hormone that signals the initiation of parturition. Proc Natl Acad Sci U S A 2004; 101:4978-83. [PMID: 15044702 PMCID: PMC387359 DOI: 10.1073/pnas.0401124101] [Citation(s) in RCA: 242] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Parturition is timed to begin only after the developing embryo is sufficiently mature to survive outside the womb. It has been postulated that the signal for the initiation of parturition arises from the fetus although the nature and source of this signal remain obscure. Herein, we provide evidence that this signal originates from the maturing fetal lung. In the mouse, secretion of the major lung surfactant protein, surfactant protein A (SP-A), was first detected in amniotic fluid (AF) at 17 days postcoitum, rising progressively to term (19 days postcoitum). Expression of IL-1beta in AF macrophages and activation of NF-kappaB in the maternal uterus increased with the gestational increase in SP-A. SP-A stimulated IL-1beta and NF-kappaB expression in cultured AF macrophages. Studies using Rosa 26 Lac-Z (B6;129S-Gt(rosa)26Sor) (Lac-Z) mice revealed that fetal AF macrophages migrate to the uterus with the gestational increase in AF SP-A. Intraamniotic (i.a.) injection of SP-A caused preterm delivery of fetuses within 6-24 h. By contrast, injection of an SP-A antibody or NF-kappaB inhibitor into AF delayed labor by >24 h. We propose that augmented production of SP-A by the fetal lung near term causes activation and migration of fetal AF macrophages to the maternal uterus, where increased production of IL-1beta activates NF-kappaB, leading to labor. We have revealed a response pathway that ties augmented surfactant production by the maturing fetal lung to the initiation of labor. We suggest that SP-A secreted by the fetal lung serves as a hormone of parturition.
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Affiliation(s)
- Jennifer C Condon
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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20
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Herrmann T, van der Hoeven F, Grone HJ, Stewart AF, Langbein L, Kaiser I, Liebisch G, Gosch I, Buchkremer F, Drobnik W, Schmitz G, Stremmel W. Mice with targeted disruption of the fatty acid transport protein 4 (Fatp 4, Slc27a4) gene show features of lethal restrictive dermopathy. J Cell Biol 2003; 161:1105-15. [PMID: 12821645 PMCID: PMC2173002 DOI: 10.1083/jcb.200207080] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The fatty acid transport protein family is a group of evolutionarily conserved proteins that are involved in the cellular uptake and metabolism of long and very long chain fatty acids. However, little is known about their respective physiological roles. To analyze the functional significance of fatty acid transport protein 4 (Fatp4, Slc27a4), we generated mice with a targeted disruption of the Fatp4 gene. Fatp4-null mice displayed features of a neonatally lethal restrictive dermopathy. Their skin was characterized by hyperproliferative hyperkeratosis with a disturbed epidermal barrier, a flat dermal-epidermal junction, a reduced number of pilo-sebaceous structures, and a compact dermis. The rigid skin consistency resulted in an altered body shape with facial dysmorphia, generalized joint flexion contractures, and impaired movement including suckling and breathing deficiencies. Lipid analysis demonstrated a disturbed fatty acid composition of epidermal ceramides, in particular a decrease in the C26:0 and C26:0-OH fatty acid substitutes. These findings reveal a previously unknown, essential function of Fatp4 in the formation of the epidermal barrier.
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Affiliation(s)
- Thomas Herrmann
- Dept. of Internal Medicine IV, University of Heidelberg, Bergheimer Str. 58, 69115 Heidelberg, Germany.
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21
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Epaud R, Ikegami M, Whitsett JA, Jobe AH, Weaver TE, Akinbi HT. Surfactant protein B inhibits endotoxin-induced lung inflammation. Am J Respir Cell Mol Biol 2003; 28:373-8. [PMID: 12594064 DOI: 10.1165/rcmb.2002-0071oc] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Transgenic mice, in which the level of surfactant protein (SP)-B mature peptide varied 5.6-fold between SP-B(+/-) and SP-B-overexpressing lines (SP-B+/+/+), were used to test the hypothesis that SP-B protects against endotoxin-induced lung inflammation. Intratracheal administration of endotoxin resulted in significantly lower concentration of SP-B mature peptide and elevated levels of total protein in bronchoalveolar lavage fluid of SP-B(+/-) mice compared with SP-B-overexpressing mice, indicating that endotoxin treatment leads to impairment of SP-B expression coincident with increased lung injury in SP-B(+/-) mice. Recruitment of inflammatory cells and elaboration of proinflammatory cytokines in bronchoalveolar lavage fluid were reduced in SP-B-overexpressing mice compared with SP-B(+/-) mice, suggesting that SP-B inhibited endotoxin-induced lung inflammation. Lung compliance and tissue damping were significantly decreased in SP-B(+/+) and SP-B(+/-) mice, but were not changed in SP-B(+/+/+) mice, consistent with a protective effect of SP-B. The minimum surface tension of large aggregate surfactant was significantly lower for surfactant isolated from SP-B-overexpressing mice, both in the absence and the presence of added plasma proteins. These data suggest that SP-B protected against endotoxin-induced lung inflammation by enhancing surfactant function, resulting in reduced lung injury, decreased influx of inflammatory cells, and lower cytokine levels; in contrast, levels of SP-B in SP-B(+/-) mice were further decreased by endotoxin treatment, likely exacerbating lung injury in this group.
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Affiliation(s)
- Ralph Epaud
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
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22
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Rice WR, Conkright JJ, Na CL, Ikegami M, Shannon JM, Weaver TE. Maintenance of the mouse type II cell phenotype in vitro. Am J Physiol Lung Cell Mol Physiol 2002; 283:L256-64. [PMID: 12114186 DOI: 10.1152/ajplung.00302.2001] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The purpose of this study was to identify culture conditions for maintenance of isolated mouse type II cells with intact surfactant protein (SP) and phospholipid production. Type II cells were isolated from 6-wk-old mice and cultured on Matrigel matrix-rat tail collagen (70:30 vol/vol) in bronchial epithelial cell growth medium minus hydrocortisone plus 5% charcoal-stripped FBS and 10 ng/ml keratinocyte growth factor. Under these conditions, type II cells actively produced surfactant phospholipids and proteins for at least 7 days. Synthesis and secretion of surfactant phospholipids and SP-A, -B, -C, and -D declined on day 1 of culture but recovered by day 3, reaching levels comparable to or exceeding freshly isolated cells by day 5. Abundant lamellar bodies were readily apparent in cells examined on days 5 and 7, and a surfactant pellet was recovered by centrifugation of media harvested on each day of culture. Secretion of SP-B, SP-C, and phosphatidylcholine was stimulated by phorbol 12-myristate 13-acetate and was inhibited by compound 48/80. When tested with a bubble surfactometer, surfactant secreted by type II cells on day 5 of culture lowered surface tension to 5.2 +/- 2.3 mN/m. This is the first description of the synthesis and secretion of a functional surfactant complex by mouse type II cells after 7 days in primary culture.
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Affiliation(s)
- Ward R Rice
- Division of Pulmonary Biology, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA.
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23
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Palaniyar N, Zhang L, Kuzmenko A, Ikegami M, Wan S, Wu H, Korfhagen TR, Whitsett JA, McCormack FX. The role of pulmonary collectin N-terminal domains in surfactant structure, function, and homeostasis in vivo. J Biol Chem 2002; 277:26971-9. [PMID: 12015304 DOI: 10.1074/jbc.m110080200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The N-terminal domains of the lung collectins, surfactant proteins A (SP-A) and D (SP-D), are critical for surfactant phospholipid interactions and surfactant homeostasis, respectively. To further assess the importance of lung collectin N-terminal domains in surfactant structure and function, a chimeric SP-D/SP-A (D/A) gene was constructed by substituting nucleotides encoding amino acids Asn(1)-Ala(7) of rat SP-A with the corresponding N-terminal sequences from rat SP-D, Ala(1)-Asn(25). Recombinant D/A migrated as a 35-kDa band on reducing SDS-PAGE and as a ladder of disulfide-linked multimers under nonreducing conditions. The recombinant D/A bound and aggregated phosphatidylcholine containing vesicles as effectively as rat SP-A. Mice in which endogenous pulmonary collectins were replaced with D/A were developed by human SP-C promoter-driven overexpression of the D/A gene in SP-A(-/-) and SP-D(-/-) animals. Analysis of lavage fluid from SP-A(-/-,D/A) mice revealed that glycosylated, oligomeric D/A was secreted into the air spaces at levels that were comparable with the authentic collectins and that the N-terminal interchange converted SP-A from a "bouquet" to a cruciform configuration. Transmission electron microscopy of surfactant from the SP-A(-/-,D/A) mice revealed atypical tubular myelin containing central "target-like" electron density. Surfactant isolated from SP-A(-/-,D/A) mice exhibited elevated surface tension both in the presence and absence of plasma inhibitors, but whole lung compliance of the SP-A(-/-,D/A) animals was not different from the SP-A(-/-) littermates. Lung-specific overexpression of D/A in the SPD(-/-) mouse resulted in hetero-oligomer formation with mouse SP-A and did not correct the air space dilation or phospholipidosis that occurs in the absence of SP-D. These studies indicate that the N terminus of SP-D 1) can functionally replace the N terminus of SP-A for lipid aggregation and tubular myelin formation, but not for surface tension lowering properties of SP-A, and 2) is not sufficient to reverse the structural and metabolic pulmonary defects in the SP-D(-/-) mouse.
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Affiliation(s)
- Nades Palaniyar
- Division of Pulmonary/Critical Care Medicine, Department of Medicine, Children's Hospital Research Foundation, University of Cincinnati School of Medicine, Cincinnati, OH 45267-0564, USA
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24
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Quintero OA, Korfhagen TR, Wright JR. Surfactant protein A regulates surfactant phospholipid clearance after LPS-induced injury in vivo. Am J Physiol Lung Cell Mol Physiol 2002; 283:L76-85. [PMID: 12060563 DOI: 10.1152/ajplung.00418.2001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Previous in vitro studies have suggested that surfactant protein A (SP-A) may play a role in pulmonary surfactant homeostasis by mediating surfactant secretion and clearance. However, mice made deficient in SP-A [SP-A (-/-) animals] have relatively normal levels of surfactant compared with wild-type SP-A (+/+) animals. We hypothesize that SP-A may play a role in surfactant homeostasis after acute lung injury. Bacterial lipopolysaccharide was instilled into the lungs of SP-A (-/-) mice and SP-A (+/+) mice to induce injury. Surfactant phospholipid levels were increased 1.6-fold in injured SP-A (-/-) animals, although injury did not alter [3H]choline or [14C]palmitate incorporation into dipalmitoylphosphatidylcholine (DPPC), suggesting no change in surfactant synthesis/secretion 12 h after injury. Clearance of [3H]DPPC from the lungs of injured SP-A (-/-) animals was decreased by approximately 40%. Instillation of 50 microg of exogenous SP-A rescued both the clearance defect and the increased phospholipid defect in injured SP-A (-/-) animals, suggesting that SP-A may play a role in regulating clearance of surfactant phospholipids after acute lung injury.
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Affiliation(s)
- Omar A Quintero
- Department of Cell Biology, Duke University, Durham, North Carolina 27710, USA
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25
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Zhang L, Hartshorn KL, Crouch EC, Ikegami M, Whitsett JA. Complementation of pulmonary abnormalities in SP-D(-/-) mice with an SP-D/conglutinin fusion protein. J Biol Chem 2002; 277:22453-9. [PMID: 11956209 DOI: 10.1074/jbc.m201632200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Surfactant protein D (SP-D) and serum conglutinin are closely related members of the collectin family of host defense lectins. Although normally synthesized at different anatomic sites, both proteins participate in the innate immune response to microbial challenge. To discern the roles of specific domains in the function of SP-D in vivo, a fusion protein (SP-D/Cong(neck+CRD)) consisting of the NH(2)-terminal and collagenous domains of rat SP-D (rSP-D) and the neck and carbohydrate recognition domains (CRDs) of bovine conglutinin (Cong) was expressed in the respiratory epithelium of SP-D gene-targeted (SP-D(-/-)) mice. While SP-D/Cong(neck+CRD) fusion protein did not affect lung morphology and surfactant phospholipid levels in the lungs of wild type mice, the chimeric protein substantially corrected the increased lung phospholipids in SP-D(-/-) mice. The SP-D/Cong(neck+CRD) fusion protein also completely corrected defects in influenza A clearance and inhibited the exaggerated inflammatory response that occurs following viral infection. However, the chimeric protein did not ameliorate the ongoing lung inflammation, enhanced metalloproteinase expression, and alveolar destruction that characterize this model of SP-D deficiency. By contrast, a single arm mutant (RrSP-D(Ser15,20)) partially restored antiviral activity but otherwise failed to rescue the deficient phenotype. Our findings directly implicate the CRDs of both SP-D and conglutinin in host defense in vivo. Our findings also strongly suggest that the molecular mechanisms underlying impaired pulmonary host defense and abnormal lipid metabolism are distinct from those that promote ongoing inflammation and the development of emphysema.
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Affiliation(s)
- Liqian Zhang
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA
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26
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McCormack FX, Whitsett JA. The pulmonary collectins, SP-A and SP-D, orchestrate innate immunity in the lung. J Clin Invest 2002. [DOI: 10.1172/jci0215293] [Citation(s) in RCA: 259] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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27
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McCormack FX, Whitsett JA. The pulmonary collectins, SP-A and SP-D, orchestrate innate immunity in the lung. J Clin Invest 2002; 109:707-12. [PMID: 11901176 PMCID: PMC150919 DOI: 10.1172/jci15293] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Francis X McCormack
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45267-0564, USA.
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28
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Klein JM, McCarthy TA, Dagle JM, Snyder JM. Antisense inhibition of surfactant protein A decreases tubular myelin formation in human fetal lung in vitro. Am J Physiol Lung Cell Mol Physiol 2002; 282:L386-93. [PMID: 11839531 DOI: 10.1152/ajplung.00410.2000] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Surfactant protein A (SP-A) is the most abundant of the surfactant-associated proteins. SP-A is involved in the formation of tubular myelin, the modulation of the surface tension-reducing properties of surfactant phospholipids, the metabolism of surfactant phospholipids, and local pulmonary host defense. We hypothesized that elimination of SP-A would alter the regulation of SP-B gene expression and the formation of tubular myelin. Midtrimester human fetal lung explants were cultured for 3-5 days in the presence or absence of an antisense 18-mer phosphorothioate oligonucleotide (ON) complementary to SP-A mRNA. After 3 days in culture, SP-A mRNA was undetectable in antisense ON-treated explants. After 5 days in culture, levels of SP-A protein were also decreased by antisense treatment. SP-B mRNA levels were not affected by the antisense SP-A ON treatment. However, there was decreased tubular myelin formation in the antisense SP-A ON-treated tissue. We conclude that selective elimination of SP-A mRNA and protein results in a decrease in tubular myelin formation in human fetal lung without affecting SP-B mRNA. We speculate that SP-A is critical to the formation of tubular myelin during human lung development and that the regulation of SP-B gene expression is independent of SP-A gene expression.
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Affiliation(s)
- Jonathan M Klein
- Departments of Pediatrics, University of Iowa, Iowa City, Iowa 52242-1083, USA.
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29
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Malloy JL, Veldhuizen RAW, McCormack FX, Korfhagen TR, Whitsett JA, Lewis JF. Pulmonary surfactant and inflammation in septic adult mice: role of surfactant protein A. J Appl Physiol (1985) 2002; 92:809-16. [PMID: 11796696 DOI: 10.1152/japplphysiol.00628.2001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Surfactant alterations, alveolar cytokine changes, and the role of surfactant protein (SP)-A in septic mice were investigated. Sepsis was induced via cecal ligation and perforation (CLP). Septic and sham mice were euthanized at 0, 3, 6, 9, 12, 15, and 18 h after surgery. Mice deficient in SP-A and mice that overexpressed SP-A were euthanized 18 h after surgery. In wild-type, sham-operated mice, surfactant pool sizes were similar at all time points, whereas in the CLP groups there was a significant decrease in small-aggregate surfactant pool sizes beginning 6 h after CLP. Interleukin-6 concentrations in bronchoalveolar lavage fluid from septic animals increased from 6 to 18 h after surgery. Identical surfactant alterations and concentrations of cytokines were observed in septic mice that were SP-A deficient or that overexpressed SP-A. In conclusion, alterations of pulmonary surfactant and alveolar cytokines occur simultaneously, 6 h after a systemic insult. In addition, we did not detect a role for SP-A in regulating surfactant phospholipid pool sizes or pulmonary inflammation in septic mice.
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Affiliation(s)
- Jaret L Malloy
- Department of Physiology, Lawson Health Research Institute, University of Western Ontario, London, Ontario, Canada N6A 4V2
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30
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Ochs M, Johnen G, Müller KM, Wahlers T, Hawgood S, Richter J, Brasch F. Intracellular and intraalveolar localization of surfactant protein A (SP-A) in the parenchymal region of the human lung. Am J Respir Cell Mol Biol 2002; 26:91-8. [PMID: 11751208 DOI: 10.1165/ajrcmb.26.1.4570] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Although it is clearly established that surfactant protein A (SP-A) is secreted by type II pneumocytes as a component of pulmonary surfactant, its secretion pathway as well as its subcellular localization in the human lung are uncertain. We therefore studied the intracellular and intra-alveolar localization of SP-A in eight adult human lungs by immunohistochemistry and immunoelectron microscopy. Only type II pneumocytes could be identified as SP-A positive cells within the parenchymal region. SP-A was localized mainly in small vesicles and multivesicular bodies close to the apical plasma membrane. Only few lamellar bodies were weakly labeled at their outer membranes. Stereologic analysis showed this weak signal to be due to specific labeling. In the alveolar space, lamellar body-like surfactant forms in close proximity to tubular myelin were labeled for SP-A at their periphery. The strongest SP-A labeling was found over tubular myelin figures. Labeling for SP-A was also found in close association with the surface film and unilamellar vesicles. Our results support the hypothesis that, in the human lung, SP-A is mainly secreted into the alveolar space via an alternative pathway that largely bypasses the lamellar bodies. After secretion, the outer membranes of unwinding lamellar bodies become enriched with SP-A when tubular myelin formation is initiated. SP-A may also be involved in the transition of tubular myelin into the surface film.
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Affiliation(s)
- Matthias Ochs
- Department of Anatomy, Division of Electron Microscopy, University of Göttingen, Göttingen, Germany
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31
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Conkright JJ, Na CL, Weaver TE. Overexpression of surfactant protein-C mature peptide causes neonatal lethality in transgenic mice. Am J Respir Cell Mol Biol 2002; 26:85-90. [PMID: 11751207 DOI: 10.1165/ajrcmb.26.1.4686] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Surfactant replacement preparations containing either surfactant protein (SP)-B or SP-C significantly improve lung function in surfactant-deficient infants, suggesting that these peptides may be functionally redundant. SP-B is absent and SP-C is greatly diminished in the airspaces of SP-B (-/-) mice, which die of respiratory distress syndrome (RDS) shortly after birth. The goal of this study was to determine if elevated expression of SP-C mature peptide could reverse the neonatal lethality in SP-B (-/-) mice. SP-C peptide (residues 24-57 of mouse SP-C proprotein) with a hemagglutinin epitope (SP-C(24-57)HA) was expressed in type II cells of transgenic mice, with the goal of crossing these animals into the SP-B (-/-) background. Unexpectedly, expression of the SP-C(24-57)HA transgene resulted in delayed/arrested lung development and lethal, neonatal RDS of all transgenic progeny in two independent transgenic lines. In transgenic mice, SP-C(24-57)HA was localized predominantly to the endoplasmic reticulum and Golgi; in contrast, SP-B and SP-C were very difficult to detect in the endoplasmic reticulum of wild-type mice. These results suggest that elevated expression of SP-C(24-57)HA in type II cells resulted in aggregation of SP-C in the early secretory pathway, leading to cytotoxicity and, ultimately, altered lung development.
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32
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Harrison BC, Bell ML, Allen DL, Byrnes WC, Leinwand LA. Skeletal muscle adaptations in response to voluntary wheel running in myosin heavy chain null mice. J Appl Physiol (1985) 2002; 92:313-22. [PMID: 11744674 DOI: 10.1152/japplphysiol.00832.2001] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
10.1152/ japplphysiol.00832.2001.-To examine the effects of gene inactivation on the plasticity of skeletal muscle, mice null for a specific myosin heavy chain (MHC) isoform were subjected to a voluntary wheel-running paradigm. Despite reduced running performance compared with nontransgenic C57BL/6 mice (NTG), both MHC IIb and MHC IId/x null animals exhibited increased muscle fiber size and muscle oxidative capacity with wheel running. In the MHC IIb null animals, there was no significant change in the percentage of muscle fibers expressing a particular MHC isoform with voluntary wheel running at any time point. In MHC IId/x null mice, wheel running produced a significant increase in the percentage of fibers expressing MHC IIa and MHC I and a significant decrease in the percentage of fibers expressing MHC IIb. Muscle pathology was not affected by wheel running for either MHC null strain. In summary, despite their phenotypes, MHC null mice do engage in voluntary wheel running. Although this wheel-running activity is lessened compared with NTG, there is evidence of distinct patterns of muscle adaptation in both null strains.
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Affiliation(s)
- B C Harrison
- Department of Kinesiology and Applied Physiology, Cellular and Developmental Biology, University of Colorado at Boulder, 80309, USA
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33
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Ikegami M, Elhalwagi BM, Palaniyar N, Dienger K, Korfhagen T, Whitsett JA, McCormack FX. The collagen-like region of surfactant protein A (SP-A) is required for correction of surfactant structural and functional defects in the SP-A null mouse. J Biol Chem 2001; 276:38542-8. [PMID: 11504713 DOI: 10.1074/jbc.m102054200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pulmonary surfactant isolated from gene-targeted surfactant protein A null mice (SP-A(-/-)) is deficient in the surfactant aggregate tubular myelin and has surface tension-lowering activity that is easily inhibited by serum proteins in vitro. To further elucidate the role of SP-A and its collagen-like region in surfactant function, we used the human SP-C promoter to drive expression of rat SP-A (rSPA) or SP-A containing a deletion of the collagen-like domain (DeltaG8-P80) in the Clara cells and alveolar type II cells of SP-A(-/-) mice. The level of the SP-A in the alveolar wash of the SP-A(-/-,rSP-A) and SP-A(-/-,DeltaG8-P80) mice was 6.1-and 1.3-fold higher, respectively, than in the wild type controls. Tissue levels of saturated phosphatidylcholine were slightly reduced in the SP-A(-/-,rSP-A) mice compared with SP-A(-/-) littermates. Tubular myelin was present in the large surfactant aggregates isolated from the SP-A(-/-,rSP-A) lines but not in the SP-A(-/-,DeltaG8-P80) mice or SP-A(-/-) controls. The equilibrium and minimum surface tensions of surfactant from the SP-A(-/-,rSP-A) mice were similar to SP-A(-/-) controls, but both were markedly elevated in the SP-A(-/-,DeltaG8-P80) mice. There was no defect in the surface tension-lowering activity of surfactant from SP-A(+/+,DeltaG8-P80) mice, indicating that the inhibitory effect of DeltaG8-P80 on surface activity can be overcome by wild type levels of mouse SP-A. The surface activity of surfactant isolated from the SP-A(-/-,rSP-A) but not the SP-A(-/-,DeltaG8-P80) mice was more resistant than SP-A(-/-) littermate control animals to inhibition by serum proteins in vitro. Pressure volume relationships of lungs from the SP-A(-/-), SP-A(-/-,rSP-A), and SP-A(-/-,DeltaG8-P80) lines were very similar. These data indicate that expression of SP-A in the pulmonary epithelium of SP-A(-/-) animals restores tubular myelin formation and resistance of isolated surfactant to protein inhibition by a mechanism that is dependent on the collagen-like region.
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Affiliation(s)
- M Ikegami
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Cincinnati School of Medicine, Cincinnati, Ohio 45229-3039, USA
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34
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McCormack FX. Functional mapping of surfactant protein A. PEDIATRIC PATHOLOGY & MOLECULAR MEDICINE 2001; 20:293-318. [PMID: 11486735 DOI: 10.1080/15513810109168823] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Surfactant protein A (SP-A) is a highly ordered, oligomeric glycoprotein that is secreted into the airspaces of the lung by alveolar type II cells and Clara cells of the pulmonary epithelium. Although research has shown that SP-A is both a calcium-dependent phospholipid-binding protein that affects surfactant structure and function and a lectin that opsonizes diverse microbial species, our understanding of the physiologically relevant roles of SP-A in the lung remains incomplete. My review focuses on the putative biological functions of SP-A that are supported by experiments in mammals and on the structural basis of SP-A function.
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Affiliation(s)
- F X McCormack
- Division of Pulmonary and Critical Case Medicine, Univ. of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267-0564, USA.
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35
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Palaniyar N, Ikegami M, Korfhagen T, Whitsett J, McCormack FX. Domains of surfactant protein A that affect protein oligomerization, lipid structure and surface tension. Comp Biochem Physiol A Mol Integr Physiol 2001; 129:109-27. [PMID: 11369537 DOI: 10.1016/s1095-6433(01)00309-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Surfactant protein A (SP-A) is an abundant protein found in pulmonary surfactant which has been reported to have multiple functions. In this review, we focus on the structural importance of each domain of SP-A in the functions of protein oligomerization, the structural organization of lipids and the surface-active properties of surfactant, with an emphasis on ultrastructural analyses. The N-terminal domain of SP-A is required for disulfide-dependent protein oligomerization, and for binding and aggregation of phospholipids, but there is no evidence that this domain directly interacts with lipid membranes. The collagen-like domain is important for the stability and oligomerization of SP-A. It also contributes shape and dimension to the molecule, and appears to determine membrane spacing in lipid aggregates such as common myelin and tubular myelin. The neck domain of SP-A is primarily involved in protein trimerization, which is critical for many protein functions, but it does not appear to be directly involved in lipid interactions. The globular C-terminal domain of SP-A clearly plays a central role in lipid binding, and in more complex functions such as the formation and/or stabilization of curved membranes. In recent work, we have determined that the maintenance of low surface tension of surfactant in the presence of serum protein inhibitors requires cooperative interactions between the C-terminal and N-terminal domains of the molecule. This effect of SP-A requires a high degree of oligomeric assembly of the protein, and may be mediated by the activity of the protein to alter the form or physical state of surfactant lipid aggregates.
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Affiliation(s)
- N Palaniyar
- MRC Immunochemistry Unit, Department of Biochemistry, University of Oxford, South Parks Road, OX1 3QU, Oxford, UK.
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36
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Mishra A, Weaver TE, Beck DC, Rothenberg ME. Interleukin-5-mediated allergic airway inflammation inhibits the human surfactant protein C promoter in transgenic mice. J Biol Chem 2001; 276:8453-9. [PMID: 11113143 DOI: 10.1074/jbc.m009481200] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Allergen challenge in the lung of humans and animals is associated with surfactant dysfunction, but the mechanism of this effect has not been established. By using a murine model of asthma we now report the effect of allergen-induced airway inflammation on the expression of transgenes regulated by the human surfactant protein (hSP)-C promoter. The hSP-C 3.7-kilobase pair promoter was used to direct the expression of eotaxin, an eosinophil-selective chemokine, into the lungs of several transgenic lines. As expected, the transgenic mice expressed increased amounts of eotaxin mRNA and protein compared with wild-type mice. Surprisingly, following allergen challenge, there was a marked down-regulation of transgene mRNA in three independent transgenic lines. The down-regulation was in contrast to other related proteins such as endogenous eotaxin and surfactant protein D levels, which were both increased following allergen challenge. Consistent with specific down-regulation of the eotaxin transgene, there was no increase in pulmonary eosinophil levels in the transgenic mice above that found in wild-type mice. Analysis of hSP-C transgenic mice with distinct reporter genes and 3'-untranslated regions revealed that allergen challenge was directly affecting the hSP-C promoter. We hypothesized that allergen-induced down-regulation of the hSP-C promoter was related to the eosinophilic inflammation. To test this, we blocked eosinophilic inflammation in the lungs by treating mice with neutralizing antiserum against interleukin-5. Interestingly, this treatment also blocked allergen-induced inhibition of the hSP-C promoter. These results establish that allergic airway inflammation is associated with up-regulation of the surfactant proteins primarily involved in immunity, whereas down-regulation of the surfactant protein primarily involved in maintaining airway patency. Furthermore, the marked down-regulation of the hSP-C promoter is interleukin-5-dependent, implying a critical role for eosinophilic inflammation. These results suggest that alterations in surfactant protein levels may contribute to immune and airway dysfunction in asthma.
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Affiliation(s)
- A Mishra
- Division of Pulmonary Medicine, Allergy and Clinical Immunology, Department of Pediatrics, Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
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37
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Spragg RG, Lewis JF. Pathology of the surfactant system of the mature lung: second San Diego conference. Am J Respir Crit Care Med 2001; 163:280-2. [PMID: 11208658 DOI: 10.1164/ajrccm.163.1.2004028] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Knowledge of the surfactant system has grown immensely in the past decade. A variety of investigative strategies, including manipulation of surfactant protein gene expression in mice, has contributed dramatically to our understanding of the role of surfactant components in lung function. These approaches have fostered investigations that will further our knowledge of the role of lung surfactant in host defense and will provide information that should lead to improved strategies for the treatment of lung disease.
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Affiliation(s)
- R G Spragg
- Department of Medicine, University of California, San Diego, USA.
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38
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Ikegami M, Jobe AH, Whitsett J, Korfhagen T. Tolerance of SP-A-deficient mice to hyperoxia or exercise. J Appl Physiol (1985) 2000; 89:644-8. [PMID: 10926649 DOI: 10.1152/jappl.2000.89.2.644] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mice carrying a null mutation of the surfactant-associated protein A (SP-A) gene have normal respiratory function, but their surfactant lacks tubular myelin, is sensitive to protein inactivation in vitro, and contains decreased pool sizes of the biophysically active large-aggregate surfactant. We hypothesized that SP-A-deficient mice would be more susceptible to exercise-induced stress and O(2)-induced lung injury. SP-A-(-/-) and SP-A-(+/+) mice tolerated 1 h of swimming or 45 min of running on a treadmill at 15 m/min equivalently, without alterations of the amount of alveolar saturated phosphatidylcholine. After 3 days of hyperoxia, SP-A-(-/-) mice had increased alveolar protein, but pressure-volume curves were not different between groups. Alveolar protein concentration was similarly increased in SP-A-(-/-) and SP-A-(+/+) mice after 4 days of exposure to hyperoxia. Survival rates were similar after 4 days of hyperoxia. SP-A-(-/-) mice were equally tolerant to exercise and 4 days of hyperoxia, indicating that the SP-A-dependent alterations in surfactant did not result in functional deficits.
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Affiliation(s)
- M Ikegami
- Division of Pulmonary Biology, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA.
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39
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Reed JA, Ikegami M, Robb L, Begley CG, Ross G, Whitsett JA. Distinct changes in pulmonary surfactant homeostasis in common beta-chain- and GM-CSF-deficient mice. Am J Physiol Lung Cell Mol Physiol 2000; 278:L1164-71. [PMID: 10835321 DOI: 10.1152/ajplung.2000.278.6.l1164] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pulmonary alveolar proteinosis (PAP) is caused by inactivation of either granulocyte-macrophage colony-stimulating factor (GM-CSF) or GM receptor common beta-chain (beta(c)) genes in mice [GM(-/-), beta(c)(-/-)], demonstrating a critical role of GM-CSF signaling in surfactant homeostasis. To distinguish possible phenotypic differences in GM(-/-) and beta(c)(-/-) mice, surfactant metabolism was compared in beta(c)(-/-), GM(-/-), and wild-type mice. Although lung histology in beta(c)(-/-) and GM(-/-) mice was indistinguishable, distinct differences were observed in surfactant phospholipid and surfactant protein concentrations and clearance from lungs of beta(c)(-/-) and GM(-/-) mice. At 1-2 days of age, lung saturated phosphatidylcholine (Sat PC) pool sizes were higher in wild-type, beta(c)(-/-), and GM(-/-) mice compared with wild-type adult mice. In wild-type mice, Sat PC pool sizes decreased to adult levels by 7 days of age; however, Sat PC increased with advancing age in beta(c)(-/-) and GM(-/-) mice. Postnatal changes in Sat PC pool sizes were different in GM(-/-) compared with beta(c)(-/-) mice. After 7 days of age, the increased lung Sat PC pool sizes remained constant in beta(c)(-/-) mice but continued to increase in GM(-/-) mice, so that by 56 days of age, lung Sat PC pools were increased three- and sixfold, respectively, compared with wild-type controls. After intratracheal injection, the percent recovery of [(3)H]dipalmitoylphosphatidylcholine and (125)I-recombinant surfactant protein (SP) C was higher in beta(c)(-/-) compared with wild-type mice, reflecting decreased clearance in the receptor-deficient mice. The defect in clearance was significantly more severe in GM(-/-) than in beta(c)(-/-) mice. The ratio of SP Sat PC to SP-A, -B, and -C was similar in bronchoalveolar lavage fluid (BALF) from adult mice of all genotypes, but the ratio of SP-D to Sat PC was markedly increased in beta(c)(-/-) and GM(-/-) mice (10- and 5-fold, respectively) compared with wild-type mice. GM-CSF concentrations were increased in BALF but not in serum of beta(c)(-/-) mice, consistent with a pulmonary response to the lack of GM-CSF signaling. The observed differences in surfactant metabolism suggest the presence of alternative clearance mechanisms regulating surfactant homeostasis in beta(c)(-/-) and GM(-/-) mice and may provide a molecular basis for the range in severity of PAP symptoms. surfactant metabolism; alveolar macrophage; granulocyte-macrophage colony-stimulating factor
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Affiliation(s)
- J A Reed
- Children's Hospital Medical Center, Cincinnati, Ohio 43229-3039, USA
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40
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Palaniyar N, McCormack FX, Possmayer F, Harauz G. Three-dimensional structure of rat surfactant protein A trimers in association with phospholipid monolayers. Biochemistry 2000; 39:6310-6. [PMID: 10828943 DOI: 10.1021/bi992793b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Surfactant protein A (SP-A) is a C-type lectin found primarily in the lung and plays a role in innate immunity and the maintenance of surfactant integrity. To determine the three-dimensional (3D) structure of SP-A in association with a lipid ligand, we have used single particle electron crystallography and computational 3D reconstruction in combination with molecular modeling. Recombinant rat SP-A, containing a deletion of the collagen-like domain, was incubated with dipalmitoylphosphatidylcholine:egg phosphatidylcholine (1:1, wt/wt) lipid monolayers in the presence of calcium, negatively stained, and examined by transmission electron microscopy. Images of SP-A-lipid complexes with different angular orientations were used to reconstruct the 3D structure of the protein. These results showed that SP-A subunits readily formed trimers and interacted with lipid monolayers exclusively via the globular domains. A homology-based molecular model of SP-A was generated and fitted into the electron density map of the protein. The plane of the putative lipid-protein interface was relatively flat and perpendicular to the hydrophobic neck region, and the cleft region in the middle of the trimer had no apparent charge clusters. Amino acid residues that are known to affect lipid interactions, Glu(195) and Arg(197), were located at the protein-lipid interface. The molecular model indicated that the hydrophobic neck region of the SP-A did not interact with lipid monolayers but was instead involved in intratrimeric subunit interactions. The glycosylation site of SP-A was located at the side of each subunit, suggesting that the covalently linked carbohydrate moiety probably occupies the spaces between the adjacent globular domains, a location that would not sterically interfere with ligand binding.
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Affiliation(s)
- N Palaniyar
- Department of Internal Medicine, University of Cincinnati, Ohio 45267-0564, USA.
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41
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Paine R, Preston AM, Wilcoxen S, Jin H, Siu BB, Morris SB, Reed JA, Ross G, Whitsett JA, Beck JM. Granulocyte-macrophage colony-stimulating factor in the innate immune response to Pneumocystis carinii pneumonia in mice. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:2602-9. [PMID: 10679099 DOI: 10.4049/jimmunol.164.5.2602] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Innate immunity plays an important role in pulmonary host defense against Pneumocystis carinii, an important pathogen in individuals with impaired cell-mediated immunity. We investigated the role of GM-CSF in host defense in a model of P. carinii pneumonia induced by intratracheal inoculation of CD4-depleted mice. Lung GM-CSF levels increased progressively during the infection and were significantly greater than those in uninfected controls 3, 4, and 5 wk after inoculation. When GM-CSF gene-targeted mice (GM-/-) depleted of CD4+ cells were inoculated with P. carinii, the intensities of infection and inflammation were increased significantly compared with those in CD4-depleted wild-type mice. In contrast, transgenic expression of GM-CSF directed solely in the lungs of GM-/- mice (using the surfactant protein C promoter) dramatically decreased the intensity of infection and inflammation 4 wk after inoculation. The concentrations of surfactant proteins A and D were greater in both uninfected and infected GM-/- mice compared with those in wild-type controls, suggesting that this component of the innate response was preserved in the GM-/- mice. However, alveolar macrophages (AM) from GM-/- mice demonstrated impaired phagocytosis of purified murine P. carinii organisms in vitro compared with AM from wild-type mice. Similarly, AM production of TNF-alpha in response to P. carinii in vitro was totally absent in AM from GM-/- mice, while GM-CSF-replete mice produced abundant TNF in this setting. Thus, GM-CSF plays a critical role in the inflammatory response to P. carinii in the setting of impaired cell-mediated immunity through effects on AM activation.
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MESH Headings
- Animals
- Cells, Cultured
- Genetic Predisposition to Disease
- Granulocyte-Macrophage Colony-Stimulating Factor/biosynthesis
- Granulocyte-Macrophage Colony-Stimulating Factor/deficiency
- Granulocyte-Macrophage Colony-Stimulating Factor/genetics
- Granulocyte-Macrophage Colony-Stimulating Factor/physiology
- Immunity, Innate/genetics
- Lung/immunology
- Lung/metabolism
- Lung/microbiology
- Lung/pathology
- Macrophages, Alveolar/immunology
- Macrophages, Alveolar/metabolism
- Macrophages, Alveolar/microbiology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Nude
- Mice, Transgenic
- Phagocytosis/genetics
- Phagocytosis/immunology
- Pneumocystis/immunology
- Pneumonia, Pneumocystis/genetics
- Pneumonia, Pneumocystis/immunology
- Pneumonia, Pneumocystis/metabolism
- Pneumonia, Pneumocystis/pathology
- Proteolipids/genetics
- Pulmonary Surfactants/genetics
- Pulmonary Surfactants/metabolism
- Tumor Necrosis Factor-alpha/metabolism
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Affiliation(s)
- R Paine
- Division of Pulmonary and Critical Care Medicine, University of Michigan, and Department of Veterans Affairs Medical Center, Ann Arbor, MI 48105, USA.
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