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Wang Z, Li T, Lin L, Xiong Y, Chen H, Ye J, Ji J, Wang S. Investigating the effects of dexamethasone on pulmonary surfactant lipids based on lipidomics studies. Biomed Chromatogr 2024:e5937. [PMID: 38922717 DOI: 10.1002/bmc.5937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/17/2024] [Accepted: 06/01/2024] [Indexed: 06/28/2024]
Abstract
Dexamethasone, a glucocorticoid commonly used in pediatric patients, has potent anti-inflammatory and immunosuppressive properties. However, it is associated with side effects such as reduced lung function and decreased immunity. Pulmonary surfactant lipids are closely linked to lung disease and play a role in reducing surface tension, immune response and antiviral activity. The dysregulation of lipid metabolism is closely associated with lung disease. Hence, untargeted lipidomics may be instrumental in elucidating the effects of dexamethasone on pulmonary surfactant lipids. We obtained surfactant lipid samples from the bronchoalveolar lavage fluid of young mice injected subcutaneously with dexamethasone and conducted a comprehensive lipidomic analysis, comparing them with a control group. We observed a decrease in lipids, such as phosphatidylcholine, phosphatidylglycerol and phosphatidylethanolamine, and an increase in ceramide, fatty acid, diacylglycerol and monoglyceride, which may impact lung health. This study revealed the influence of dexamethasone on pulmonary surfactant lipids, offering new insights into adverse reactions in clinical settings.
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Affiliation(s)
- Zhao Wang
- Jiangsu Key Laboratory of Pediatric Respiratory Disease, Institute of Pediatrics, Medical Metabolomics Center, Pediatrics Department, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Tao Li
- Jiangsu Key Laboratory of Pediatric Respiratory Disease, Institute of Pediatrics, Medical Metabolomics Center, Pediatrics Department, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Lili Lin
- Jiangsu Key Laboratory of Pediatric Respiratory Disease, Institute of Pediatrics, Medical Metabolomics Center, Pediatrics Department, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Yingcai Xiong
- Jiangsu Key Laboratory of Pediatric Respiratory Disease, Institute of Pediatrics, Medical Metabolomics Center, Pediatrics Department, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Hui Chen
- Jiangsu Key Laboratory of Pediatric Respiratory Disease, Institute of Pediatrics, Medical Metabolomics Center, Pediatrics Department, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Jin Ye
- Jiangsu Key Laboratory of Pediatric Respiratory Disease, Institute of Pediatrics, Medical Metabolomics Center, Pediatrics Department, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Jianjian Ji
- Jiangsu Key Laboratory of Pediatric Respiratory Disease, Institute of Pediatrics, Medical Metabolomics Center, Pediatrics Department, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Shouchuan Wang
- Jiangsu Key Laboratory of Pediatric Respiratory Disease, Institute of Pediatrics, Medical Metabolomics Center, Pediatrics Department, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
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2
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Abstract
Pulmonary surfactant is a critical component of lung function in healthy individuals. It functions in part by lowering surface tension in the alveoli, thereby allowing for breathing with minimal effort. The prevailing thinking is that low surface tension is attained by a compression-driven squeeze-out of unsaturated phospholipids during exhalation, forming a film enriched in saturated phospholipids that achieves surface tensions close to zero. A thorough review of past and recent literature suggests that the compression-driven squeeze-out mechanism may be erroneous. Here, we posit that a surfactant film enriched in saturated lipids is formed shortly after birth by an adsorption-driven sorting process and that its composition does not change during normal breathing. We provide biophysical evidence for the rapid formation of an enriched film at high surfactant concentrations, facilitated by adsorption structures containing hydrophobic surfactant proteins. We examine biophysical evidence for and against the compression-driven squeeze-out mechanism and propose a new model for surfactant function. The proposed model is tested against existing physiological and pathophysiological evidence in neonatal and adult lungs, leading to ideas for biophysical research, that should be addressed to establish the physiological relevance of this new perspective on the function of the mighty thin film that surfactant provides.
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Affiliation(s)
- Fred Possmayer
- Department of Biochemistry, Western University, London, Ontario N6A 3K7, Canada
- Department of Obstetrics/Gynaecology, Western University, London, Ontario N6A 3K7, Canada
| | - Yi Y Zuo
- Department of Mechanical Engineering, University of Hawaii at Manon, Honolulu, Hawaii 96822, United States
- Department of Pediatrics, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96826, United States
| | - Ruud A W Veldhuizen
- Department of Physiology & Pharmacology, Western University, London, Ontario N6A 5C1, Canada
- Department of Medicine, Western University, London, Ontario N6A 3K7, Canada
- Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
| | - Nils O Petersen
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
- Department of Chemistry, Western University, London, Ontario N6A 5B7, Canada
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3
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Brandt R, Timm S, Gorenflos López JL, Kwame Abledu J, Kuebler WM, Hackenberger CPR, Ochs M, Lopez-Rodriguez E. Metabolic Glycoengineering Enables the Ultrastructural Visualization of Sialic Acids in the Glycocalyx of the Alveolar Epithelial Cell Line hAELVi. Front Bioeng Biotechnol 2021; 8:614357. [PMID: 33520965 PMCID: PMC7841390 DOI: 10.3389/fbioe.2020.614357] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 11/23/2020] [Indexed: 12/13/2022] Open
Abstract
The glycocalyx—a plethora of sugars forming a dense layer that covers the cell membrane—is commonly found on the epithelial surface of lumen forming tissue. New glycocalyx specific properties have been defined for various organs in the last decade. However, in the lung alveolar epithelium, its structure and functions remain almost completely unexplored. This is partly due to the lack of physiologically relevant, cost effective in vitro models. As the glycocalyx is an essential but neglected part of the alveolar epithelial barrier, understanding its properties holds the promise to enhance the pulmonary administration of drugs and delivery of nanoparticles. Here, using air-liquid-interface (ALI) cell culture, we focus on combining metabolic glycoengineering with glycan specific electron and confocal microscopy to visualize the glycocalyx of a recently immortalized human alveolar epithelial cell line (hAELVi). For this purpose, we applied different bioorthogonal labeling approaches to visualize sialic acid—an amino sugar that provides negative charge to the lung epithelial glycocalyx—using both fluorescence and gold-nanoparticle labeling. Further, we compared mild chemical fixing/freeze substitution and standard cytochemical electron microscopy embedding protocols for their capacity of contrasting the glycocalyx. In our study, we established hAELVi cells as a convenient model for investigating human alveolar epithelial glycocalyx. Transmission electron microscopy revealed hAELVi cells to develop ultrastructural features reminiscent of alveolar epithelial type II cells (ATII). Further, we visualized extracellular uni- and multilamellar membranous structures in direct proximity to the glycocalyx at ultrastructural level, indicating putative interactions. The lamellar membranes were able to form structures of higher organization, and we report sialic acid to be present within those. In conclusion, combining metabolite specific glycoengineering with ultrastructural localization presents an innovative method with high potential to depict the molecular distribution of individual components of the alveolar epithelial glycocalyx and its interaction partners.
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Affiliation(s)
- Raphael Brandt
- Institute of Functional Anatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Sara Timm
- Core Facility Electron Microscopy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jacob L Gorenflos López
- Department Chemical Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.,Department of Chemistry, Humboldt Universität zu Berlin, Berlin, Germany
| | | | - Wolfgang M Kuebler
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,German Center for Lung Research (DZL), Berlin, Germany
| | - Christian P R Hackenberger
- Department Chemical Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.,Department of Chemistry, Humboldt Universität zu Berlin, Berlin, Germany
| | - Matthias Ochs
- Institute of Functional Anatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Core Facility Electron Microscopy, Charité - Universitätsmedizin Berlin, Berlin, Germany.,German Center for Lung Research (DZL), Berlin, Germany
| | - Elena Lopez-Rodriguez
- Institute of Functional Anatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany
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4
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Homma S, Ebina M, Kuwano K, Goto H, Sakai F, Sakamoto S, Johkoh T, Sugino K, Tachibana T, Terasaki Y, Nishioka Y, Hagiwara K, Hashimoto N, Hasegawa Y, Hebisawa A. Intractable diffuse pulmonary diseases: Manual for diagnosis and treatment. Respir Investig 2021; 59:8-33. [PMID: 32622842 DOI: 10.1016/j.resinv.2020.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/17/2020] [Accepted: 04/22/2020] [Indexed: 06/11/2023]
Abstract
This manual has been compiled by a joint production committee with the Diffuse Lung Disease Assembly of the Japanese Respiratory Society (JRS) to provide a practical manual for the epidemiology, diagnosis, and treatment of intractable diffuse pulmonary diseases. The contents are based upon the results of research into these diseases by the Diffuse Pulmonary Diseases Study Group (principal researcher: Sakae Homma) supported by the FY2014-FY2016 Health and Labor Sciences Research Grant on Intractable Diseases. This manual focuses on: 1) pulmonary alveolar microlithiasis, 2) bronchiolitis obliterans, and 3) Hermansky-Pudlak Syndrome with interstitial pneumonia. As these are rare/intractable diffuse lung diseases (2 and 3 were first recognized as specified intractable diseases in 2015), there have not been sufficient epidemiological studies made, and there has been little progress in formulating diagnostic criteria and severity scales; however, the results of Japan's first surveys and research into such details are presented herein. In addition, the manual provides treatment guidance and actual cases for each disease, aiming to assist in the establishment of future modalities. The manual was produced with the goal of enabling clinicians specialized in respiratory apparatus to handle these diseases in clinical settings and of further advancing future research and treatment.
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Affiliation(s)
- Sakae Homma
- Department of Advanced and Integrated Interstitial Lung Diseases Research, School of Medicine, Toho University, Tokyo, Japan.
| | - Masahito Ebina
- Department of Respiratory Medicine in the 1st Internal Medicine, Tohoku Medical and Pharmaceutical University School of Medicine, Sendai, Japan.
| | - Kazuyoshi Kuwano
- Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
| | - Hisatsugu Goto
- Department of Respiratory Medicine and Rheumatology, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan.
| | - Fumikazu Sakai
- Department of Diagnostic Radiology, Saitama International Medical Center, Saitama Medical University, Saitama, Japan.
| | - Susumu Sakamoto
- Department of Respiratory Medicine, Toho University Omori Medical Center, Tokyo, Japan.
| | - Takeshi Johkoh
- Department of Radiology, Kinki Central Hospital of Mutual Aid Association of Public School Teachers, Hyogo, Japan.
| | - Keishi Sugino
- Department of Respiratory Medicine, Toho University Omori Medical Center, Tokyo, Japan.
| | - Teruo Tachibana
- Department of Internal Medicine, Aizenbashi Hospital, Osaka, Japan.
| | - Yasahiro Terasaki
- Department of Pathology (Analytic Human Pathology), Nippon Medical School, Tokyo, Japan.
| | - Yasuhiko Nishioka
- Department of Respiratory Medicine and Rheumatology, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan.
| | - Koichi Hagiwara
- Division of Pulmonary Medicine, Jichi Medical University, Saitama, Japan.
| | - Naozumi Hashimoto
- Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Aichi, Japan.
| | - Yoshinori Hasegawa
- Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Aichi, Japan.
| | - Akira Hebisawa
- National Hospital Organization Tokyo Medical Center, Tokyo, Japan.
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5
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Li Y, Kinting S, Höppner S, Forstner ME, Uhl O, Koletzko B, Griese M. Metabolic labelling of choline phospholipids probes ABCA3 transport in lamellar bodies. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:158516. [DOI: 10.1016/j.bbalip.2019.158516] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 08/21/2019] [Accepted: 08/26/2019] [Indexed: 01/09/2023]
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6
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Lung surfactant metabolism: early in life, early in disease and target in cell therapy. Cell Tissue Res 2016; 367:721-735. [PMID: 27783217 DOI: 10.1007/s00441-016-2520-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 09/27/2016] [Indexed: 01/07/2023]
Abstract
Lung surfactant is a complex mixture of lipids and proteins lining the alveolar epithelium. At the air-liquid interface, surfactant lowers surface tension, avoiding alveolar collapse and reducing the work of breathing. The essential role of lung surfactant in breathing and therefore in life, is highlighted by surfactant deficiency in premature neonates, which causes neonatal respiratory distress syndrome and results in early death after birth. In addition, defects in surfactant metabolism alter lung homeostasis and lead to disease. Special attention should be paid to two important key cells responsible for surfactant metabolism: alveolar epithelial type II cells (AE2C) and alveolar macrophages (AM). On the one hand, surfactant deficiency coming from abnormal AE2C function results in high surface tension, promoting alveolar collapse and mechanical stress in the epithelium. This epithelial injury contributes to tissue remodeling and lung fibrosis. On the other hand, impaired surfactant catabolism by AM leads to accumulation of surfactant in air spaces and the associated altered lung function in pulmonary alveolar proteinosis (PAP). We review here two recent cell therapies that aim to recover the activity of AE2C or AM, respectively, therefore targeting the restoring of surfactant metabolism and lung homeostasis. Applied therapies successfully show either transplantation of healthy AE2C in fibrotic lungs, to replace injured AE2C cells and surfactant, or transplantation of bone marrow-derived macrophages to counteract accumulation of surfactant lipid and proteinaceous material in the alveolar spaces leading to PAP. These therapies introduce an alternative treatment with great potential for patients suffering from lung diseases.
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7
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Lin S, Ikegami M, Moon C, Naren AP, Shannon JM. Lysophosphatidylcholine Acyltransferase 1 (LPCAT1) Specifically Interacts with Phospholipid Transfer Protein StarD10 to Facilitate Surfactant Phospholipid Trafficking in Alveolar Type II Cells. J Biol Chem 2015; 290:18559-74. [PMID: 26048993 DOI: 10.1074/jbc.m115.666701] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Indexed: 01/10/2023] Open
Abstract
Pulmonary surfactant, a mixture of proteins and phospholipids, plays an important role in facilitating gas exchange by maintaining alveolar stability. Saturated phosphatidylcholine (SatPC), the major component of surfactant, is synthesized both de novo and by the remodeling of unsaturated phosphatidylcholine (PC) by lyso-PC acyltransferase 1 (LPCAT1). After synthesis in the endoplasmic reticulum, SatPC is routed to lamellar bodies (LBs) for storage prior to secretion. The mechanism by which SatPC is transported to LB is not understood. The specificity of LPCAT1 for lyso-PC as an acyl acceptor suggests that formation of SatPC via LPCAT1 reacylation is a final step in SatPC synthesis prior to transport. We hypothesized that LPCAT1 forms a transient complex with SatPC and specific phospholipid transport protein(s) to initiate trafficking of SatPC from the endoplasmic reticulum to the LB. Herein we have assessed the ability of different StarD proteins to interact with LPCAT1. We found that LPCAT1 interacts with StarD10, that this interaction is direct, and that amino acids 79-271 of LPCAT1 and the steroidogenic acute regulatory protein-related lipid transfer (START) domain of START domain-containing protein 10 (StarD10) are sufficient for this interaction. The role of StarD10 in trafficking of phospholipid to LB was confirmed by the observation that knockdown of StarD10 significantly reduced transport of phospholipid to LB. LPCAT1 also interacted with one isoform of StarD7 but showed no interaction with StarD2/PC transfer protein.
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Affiliation(s)
- Sui Lin
- From the Divisions of Pulmonary Biology and
| | | | - Changsuk Moon
- Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Anjaparavanda P Naren
- Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
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8
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Wong JH, Halliday GM, Kim WS. Exploring myelin dysfunction in multiple system atrophy. Exp Neurobiol 2014; 23:337-44. [PMID: 25548533 PMCID: PMC4276804 DOI: 10.5607/en.2014.23.4.337] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 10/15/2014] [Accepted: 10/15/2014] [Indexed: 11/19/2022] Open
Abstract
Multiple system atrophy (MSA) is a rare, yet fatal neurodegenerative disease that presents clinically with autonomic failure in combination with parkinsonism or cerebellar ataxia. MSA impacts on the autonomic nervous system affecting blood pressure, heart rate and bladder function, and the motor system affecting balance and muscle movement. The cause of MSA is unknown, no definitive risk factors have been identified, and there is no cure or effective treatment. The definitive pathology of MSA is the presence of α-synuclein aggregates in the brain and therefore MSA is classified as an α-synucleinopathy, together with Parkinson's disease and dementia with Lewy bodies. Although the molecular mechanisms of misfolding, fibrillation and aggregation of α-synuclein partly overlap with other α-synucleinopathies, the pathological pathway of MSA is unique in that the principal site for α-synuclein deposition is in the oligodendrocytes rather than the neurons. The sequence of pathological events of MSA is now recognized as abnormal protein redistributions in oligodendrocytes first, followed by myelin dysfunction and then neurodegeneration. Oligodendrocytes are responsible for the production and maintenance of myelin, the specialized lipid membrane that encases the axons of all neurons in the brain. Myelin is composed of lipids and two prominent proteins, myelin basic protein and proteolipid protein. In vitro studies suggest that aberration in protein distribution and lipid transport may lead to myelin dysfunction in MSA. The purpose of this perspective is to bring together available evidence to explore the potential role of α-synuclein, myelin protein dysfunction, lipid dyshomeostasis and ABCA8 in MSA pathogenesis.
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Affiliation(s)
- Joanna H Wong
- Neuroscience Research Australia, Sydney, NSW 2031, Australia. ; School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Glenda M Halliday
- Neuroscience Research Australia, Sydney, NSW 2031, Australia. ; School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Woojin Scott Kim
- Neuroscience Research Australia, Sydney, NSW 2031, Australia. ; School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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9
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Schmiedl A, Grützner D, Hoffmann T, von Hörsten S, Stephan M. DPP4 inhibitors increase differentially the expression of surfactant proteins in Fischer 344 rats. Acta Physiol (Oxf) 2014; 212:248-61. [PMID: 25069535 DOI: 10.1111/apha.12350] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 04/17/2014] [Accepted: 07/19/2014] [Indexed: 01/21/2023]
Abstract
AIM Intact surface active agent (surfactant) composed of surfactant-associated proteins (SPs) and lipids is necessary for respiration and prevents alveoli from collapsing. CD26, a transmembrane glycoprotein exerting dipeptidyl peptidase activity (DPP4), highly expressed in lung parenchyma, is involved in inflammatory processes. A pharmacological inhibition of DPP4 influenced not only the inflammation but also elevated the SPs. Thus, DPP4 inhibitors may be a novel drug for treatment of diseases with surfactant deficiency. Therefore, we tested firstly the hypothesis that DPP4 inhibitors increase the expression of SPs in healthy rats. METHODS SP mRNA and protein expression were determined different times after nebulization of aerosolized DPP4 inhibitors [L-isoleucine-thiazolidide (L-Ile-Thia), L-valine-pyrrolidide (L-Val-Pyrr)], budesonide, saline or stereoisomers. RESULTS Compared with negative controls (1) L-Ile-Thia as well as budesonide led to a significant higher and L-Val-Pyrr had the tendency to a significant higher expression of SP-A mRNA 6 h after nebulization, (2) the expression of SP-D mRNA increased significantly 6 h after nebulization with L-Ile-Thia and 3 and 6 h after nebulization with Val-pyrr, (3) SP-B mRNA levels showed significantly higher values 3 and 6 h after nebulization with L-Val-Pyrr, (4) protein levels of SP-A, SP-B and SP-C were elevated significantly 6 h after nebulization with L-Val-Pyrr as well as with budesonide, and (5) phospholipids were also increased in response to DPP4 inhibition; the minimal surface tension was comparable. CONCLUSION DPP4 inhibition influence differently the expression of surfactant proteins in healthy rats and may be suitable to elevate surfactant synthesis in different diseases accompanied with surfactant deficiencies.
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Affiliation(s)
- A. Schmiedl
- Institute of Functional and Applied Anatomy; Hannover Medical School; Hannover Germany
| | - D. Grützner
- Institute of Functional and Applied Anatomy; Hannover Medical School; Hannover Germany
| | | | - S. von Hörsten
- Department for Experimental Therapy; Franz-Penzoldt-Center; Friedrich-Alexander-University Erlangen-Nürnberg; Erlangen Germany
| | - M. Stephan
- Clinic for Psychosomatics and Psychotherapy; Hannover Medical School; Hannover Germany
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10
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Kovacs T, Csongei V, Feller D, Ernszt D, Smuk G, Sarosi V, Jakab L, Kvell K, Bartis D, Pongracz JE. Alteration in the Wnt microenvironment directly regulates molecular events leading to pulmonary senescence. Aging Cell 2014; 13:838-49. [PMID: 24981738 PMCID: PMC4331750 DOI: 10.1111/acel.12240] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2014] [Indexed: 11/28/2022] Open
Abstract
In the aging lung, the lung capacity decreases even in the absence of diseases. The progenitor cells of the distal lung, the alveolar type II cells (ATII), are essential for the repair of the gas-exchange surface. Surfactant protein production and survival of ATII cells are supported by lipofibroblasts that are peroxisome proliferator-activated receptor gamma (PPARγ)-dependent special cell type of the pulmonary tissue. PPARγ levels are directly regulated by Wnt molecules; therefore, changes in the Wnt microenvironment have close control over maintenance of the distal lung. The pulmonary aging process is associated with airspace enlargement, decrease in the distal epithelial cell compartment and infiltration of inflammatory cells. qRT–PCR analysis of purified epithelial and nonepithelial cells revealed that lipofibroblast differentiation marker parathyroid hormone-related protein receptor (PTHrPR) and PPARγ are reduced and that PPARγ reduction is regulated by Wnt4 via a β-catenin-dependent mechanism. Using a human in vitro 3D lung tissue model, a link was established between increased PPARγ and pro-surfactant protein C (pro-SPC) expression in pulmonary epithelial cells. In the senile lung, both Wnt4 and Wnt5a levels increase and both Wnt-s increase myofibroblast-like differentiation. Alteration of the Wnt microenvironment plays a significant role in pulmonary aging. Diminished lipo- and increased myofibroblast-like differentiation are directly regulated by specific Wnt-s, which process also controls surfactant production and pulmonary repair mechanisms.
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Affiliation(s)
- Tamas Kovacs
- Medical School Department of Pharmaceutical Biotechnology University of Pécs Pécs Hungary
- János Szentágothai Research Centre University of Pécs Pécs Hungary
| | - Veronika Csongei
- Medical School Department of Pharmaceutical Biotechnology University of Pécs Pécs Hungary
- János Szentágothai Research Centre University of Pécs Pécs Hungary
| | - Diana Feller
- Medical School Department of Pharmaceutical Biotechnology University of Pécs Pécs Hungary
- János Szentágothai Research Centre University of Pécs Pécs Hungary
| | - David Ernszt
- Medical School Department of Pharmaceutical Biotechnology University of Pécs Pécs Hungary
- János Szentágothai Research Centre University of Pécs Pécs Hungary
| | - Gabor Smuk
- Medical School Department of Pathology University of Pécs Pécs Hungary
| | - Veronika Sarosi
- Medical School Department of Pulmonology University of Pécs Pécs Hungary
| | - Laszlo Jakab
- Medical School Department of Surgery University of Pécs Pécs Hungary
| | - Krisztian Kvell
- Medical School Department of Pharmaceutical Biotechnology University of Pécs Pécs Hungary
- János Szentágothai Research Centre University of Pécs Pécs Hungary
| | - Domokos Bartis
- Department of Clinical Respiratory Sciences, Centre for Translational Inflammation Research University of Birmingham Research Laboratories Queen Elizabeth Hospital Birmingham UK
| | - Judit E. Pongracz
- Medical School Department of Pharmaceutical Biotechnology University of Pécs Pécs Hungary
- János Szentágothai Research Centre University of Pécs Pécs Hungary
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11
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da Cunha MJ, da Cunha AA, Scherer EBS, Machado FR, Loureiro SO, Jaenisch RB, Guma F, Lago PD, Wyse ATS. Experimental lung injury promotes alterations in energy metabolism and respiratory mechanics in the lungs of rats: prevention by exercise. Mol Cell Biochem 2013; 389:229-38. [PMID: 24378995 DOI: 10.1007/s11010-013-1944-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 12/18/2013] [Indexed: 12/11/2022]
Abstract
In the present study we investigated the effects of lung injury on energy metabolism (succinate dehydrogenase, complex II, cytochrome c oxidase, and ATP levels), respiratory mechanics (dynamic and static compliance, elastance and respiratory system resistance) in the lungs of rats, as well as on phospholipids in bronchoalveolar lavage fluid. The protective effect of physical exercise on the alterations caused by lung injury, including lung edema was also evaluated. Wistar rats were submitted to 2 months of physical exercise. After this period the lung injury was induced by intratracheal instillation of lipopolysaccharide. Adult Wistar rats were submitted to 2 months of physical exercise and after this period the lung injury was induced by intratracheal instillation of lipopolysaccharide in dose 100 μg/100 g body weight. The sham group received isotonic saline instillation. Twelve hours after the injury was performed the respiratory mechanical and after the rats were decapitated and samples were collected. The rats subjected to lung injury presented a decrease in activities of the enzymes of the electron transport chain and ATP levels in lung, as well as the formation of pulmonary edema. A decreased lung dynamic and static compliance, as well as an increase in respiratory system resistance, and a decrease in phospholipids content were observed. Physical exercise was able to totally prevent the decrease in succinate dehydrogenase and complex II activities and the formation of pulmonary edema. It also partially prevented the increase in respiratory system resistance, but did not prevent the decrease in dynamic and static compliance, as well as in phospholipids content. These findings suggest that the mitochondrial dysfunction may be one of the important contributors to lung damage and that physical exercise may be beneficial in this pathology, although it did not prevent all changes present in lung injury.
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Affiliation(s)
- Maira J da Cunha
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, ICBS, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, Porto Alegre, RS, CEP 90035-003, Brazil
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12
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Zuo YY, Neumann AW. Pulmonary Surfactant and its in vitro Assessment Using Axisymmetric Drop Shape Analysis (ADSA): A Review. TENSIDE SURFACT DET 2013. [DOI: 10.3139/113.100255] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Recent progress in the study of pulmonary surfactant is reviewed. The first half of this paper provides general background in both physiological and clinical perspectives. The second half focuses on the in vitro assessment of pulmonary surfactant using methods based on a drop shape technique, Axisymmetric Drop Shape Analysis (ADSA). Theories, experiments, and techniques of image analysis used in these ADSA methods are briefly described. Typical applications of these methods are discussed in detail. It is concluded that the accuracy, versatility, and simplicity of these ADSA methods render them suitable to the study of pulmonary surfactant.
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13
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Abstract
The alveolar type II epithelial (ATII) cell is highly specialised for the synthesis and storage, in intracellular lamellar bodies, of phospholipid destined for secretion as pulmonary surfactant into the alveolus. Regulation of the enzymology of surfactant phospholipid synthesis and metabolism has been extensively characterised at both molecular and functional levels, but understanding of surfactant phospholipid metabolism in vivo in either healthy or, especially, diseased lungs is still relatively poorly understood. This review will integrate recent advances in the enzymology of surfactant phospholipid metabolism with metabolic studies in vivo in both experimental animals and human subjects. It will highlight developments in the application of stable isotope-labelled precursor substrates and mass spectrometry to probe lung phospholipid metabolism in terms of individual molecular lipid species and identify areas where a more comprehensive metabolic model would have considerable potential for direct application to disease states.
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Agassandian M, Mallampalli RK. Surfactant phospholipid metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:612-25. [PMID: 23026158 DOI: 10.1016/j.bbalip.2012.09.010] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 09/07/2012] [Accepted: 09/16/2012] [Indexed: 12/16/2022]
Abstract
Pulmonary surfactant is essential for life and is composed of a complex lipoprotein-like mixture that lines the inner surface of the lung to prevent alveolar collapse at the end of expiration. The molecular composition of surfactant depends on highly integrated and regulated processes involving its biosynthesis, remodeling, degradation, and intracellular trafficking. Despite its multicomponent composition, the study of surfactant phospholipid metabolism has focused on two predominant components, disaturated phosphatidylcholine that confers surface-tension lowering activities, and phosphatidylglycerol, recently implicated in innate immune defense. Future studies providing a better understanding of the molecular control and physiological relevance of minor surfactant lipid components are needed. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism.
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Affiliation(s)
- Marianna Agassandian
- Department of Medicine, Acute Lung Injury Center of Excellence, the University of Pittsburgh, Pittsburgh, PA 15213, USA
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15
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Casals C, Cañadas O. Role of lipid ordered/disordered phase coexistence in pulmonary surfactant function. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2550-62. [PMID: 22659676 DOI: 10.1016/j.bbamem.2012.05.024] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 05/03/2012] [Accepted: 05/22/2012] [Indexed: 12/27/2022]
Abstract
The respiratory epithelium has evolved to produce a complicated network of extracellular membranes that are essential for breathing and, ultimately, survival. Surfactant membranes form a stable monolayer at the air-liquid interface with bilayer structures attached to it. By reducing the surface tension at the air-liquid interface, surfactant stabilizes the lung against collapse and facilitates inflation. The special composition of surfactant membranes results in the coexistence of two distinct micrometer-sized ordered/disordered phases maintained up to physiological temperatures. Phase coexistence might facilitate monolayer folding to form three-dimensional structures during exhalation and hence allow the film to attain minimal surface tension. These folded structures may act as a membrane reserve and attenuate the increase in membrane tension during inspiration. The present review summarizes what is known of ordered/disordered lipid phase coexistence in lung surfactant, paying attention to the possible role played by domain boundaries in the monolayer-to-multilayer transition, and the correlations of biophysical inactivation of pulmonary surfactant with alterations in phase coexistence.
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Affiliation(s)
- Cristina Casals
- Departamento de Bioquimica y Biologia Molecular, Universidad Complutense de Madrid, Madrid, Spain.
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16
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Vedovelli L, Baritussio A, Carnielli VP, Simonato M, Giusti P, Cogo PE. Simultaneous measurement of phosphatidylglycerol and disaturated-phosphatidylcholine palmitate kinetics from alveolar surfactant. Study in infants with stable isotope tracer, coupled with isotope ratio mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2011; 46:986-992. [PMID: 22012664 DOI: 10.1002/jms.1979] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Disaturated-phosphatidylcholine (DSPC) and phosphatidylglycerol (PG) are respectively the first and the third most abundant phospholipid in human alveolar surfactant. Their concentration decreases in airway surfactant of adults and infants with respiratory distress syndrome and cystic fibrosis. In this study, we used mass spectrometry (IRMS) to investigate the turnover of DSPC and PG in tracheal aspirates (TA) obtained from infants with normal or diseased lungs. We studied eight infants requiring mechanical ventilation: two with no lung disease, four with diaphragmatic hernia, one with ATP-binding cassette sub-family A member 3 heterozygote mutation and one with sepsis. Patients received deuterated water for 48 h as metabolic precursors of palmitate-DSPC and palmitate-PG. Serial TAs were obtained every 6 h for five days or until extubation. DSPC and PG were isolated from TA by column and high-performance thin layer chromatography. Deuterium enrichments of palmitate-DSPC and PG residues were measured by IRMS coupled with a gas chromatographer. Median secretion time (ST), peak time (PT) and fractional synthesis rate (FSR) were 3.7 [0.9- 13.4] h, 71.0 [52.2 - 85.2] h and 6.6 [6.3 - 11.1] %/day for DSPC and 19.3 [6.4 - 22.8] h, 49.0 [33.0 - 52.5] h and 5.8 [4.8 - 10.9] %/day for PG. This study shows that it is feasible to use deuterium derived from body water to trace simultaneously airway surfactant DSPC and PG in humans. When compared within the same patient, DSPC and PG had similar fractional synthesis rates, but PG had a shorter PT, suggesting differences in the life cycle of these essential surfactant components.
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Affiliation(s)
- Luca Vedovelli
- Department of Anesthesiology and Pharmacology, University of Padua, Padua, Italy.
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17
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Simonato M, Baritussio A, Ori C, Vedovelli L, Rossi S, Dalla Massara L, Rizzi S, Carnielli VP, Cogo PE. Disaturated-phosphatidylcholine and surfactant protein-B turnover in human acute lung injury and in control patients. Respir Res 2011; 12:36. [PMID: 21429235 PMCID: PMC3072954 DOI: 10.1186/1465-9921-12-36] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Accepted: 03/24/2011] [Indexed: 01/26/2023] Open
Abstract
Background Patients with Adult Respiratory Distress Syndrome (ARDS) and Acute Lung Injury (ALI) have low concentrations of disaturated-phosphatidylcholine and surfactant protein-B in bronchoalveolar lavage fluid. No information is available on their turnover. Objectives To analyze disaturated-phosphatidylcholine and surfactant protein-B turnover in patients with ARDS/ALI and in human adults with normal lungs (controls). Methods 2H2O as precursor of disaturated-phosphatidylcholine-palmitate and 113C-Leucine as precursor of surfactant protein-B were administered intravenously to 12 patients with ARDS/ALI and to 8 controls. Disaturated-phosphatidylcholine and surfactant protein-B were isolated from serial tracheal aspirates, and their fractional synthetic rate was derived from the 2H and 13C enrichment curves, obtained by gas chromatography mass spectrometry. Disaturated-phosphatidylcholine, surfactant protein-B, and protein concentrations in tracheal aspirates were also measured. Results 1) Surfactant protein-B turned over at faster rate than disaturated-phosphatidylcholine both in ARDS/ALI patients and in controls. 2) In patients with ARDS/ALI the fractional synthesis rate of disaturated-phosphatidylcholine was 3.1 times higher than in controls (p < 0.01), while the fractional synthesis rate of surfactant protein-B was not different. 3) In ARDS/ALI patients the concentrations of disaturated-phosphatidylcholine and surfactant protein-B in tracheal aspirates were markedly and significantly reduced (17% and 40% of the control values respectively). Conclusions 1) Disaturated-phosphatidylcholine and surfactant protein-B have a different turnover both in healthy and diseased lungs. 2) In ARDS/ALI the synthesis of these two surfactant components may be differently regulated.
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18
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Niven RW. Toward managing chronic rejection after lung transplant: the fate and effects of inhaled cyclosporine in a complex environment. Adv Drug Deliv Rev 2011; 63:88-109. [PMID: 20950661 DOI: 10.1016/j.addr.2010.10.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 09/09/2010] [Accepted: 10/05/2010] [Indexed: 10/19/2022]
Abstract
The fate and effects of inhaled cyclosporine A (CsA) are considered after deposition on the lung surface. Special emphasis is given to a post-lung transplant environment and to the potential effects of the drug on the various cell types it is expected to encounter. The known stability, metabolism, pharmacokinetics and pharmacodynamics of the drug have been reviewed and discussed in the context of the lung microenvironment. Arguments support the contention that the immuno-inhibitory and anti-inflammatory effects of CsA are not restricted to T-cells. It is likely that pharmacologically effective concentrations of CsA can be sustained in the lungs but due to the complexity of uptake and action, the elucidation of effective posology must ultimately rely on clinical evidence.
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19
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Clearance in vivo of instilled [h]cholesterol from the rat lung. Biochem Res Int 2010; 2010:965716. [PMID: 21188079 PMCID: PMC3006006 DOI: 10.1155/2010/965716] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Accepted: 12/13/2009] [Indexed: 11/17/2022] Open
Abstract
Phospholipids and lung surfactant proteins are known to be recycled within the lung alveolus mainly by uptake into type II epithelial cells that secrete lipid-enriched lung surfactant. Dipalmitoyl phosphatidylcholine (DPPC) is the major component of lung surfactant lipids and cholesterol is the second most abundant. However, cholesterol turnover in vivo has not been measured and it is not known how long steroidal compounds persist in the lung in intact animals. Here we report on experiments in which radiolabeled cholesterol was instilled into the lungs of rats, then at various postinstillation periods, radioactive sterols in lavage fluid, and in postlavage whole lungs were measured in individual animals. Radioactive sterols in the lungs remained high for a week and were still detectable 46 days later. The clearance rate during the initial postinstillation week was approximately 10% per day. Both radioactive free and esterified sterols were recovered from bronchoalveolar lavage fluid and postlavage lungs.
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20
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Postle AD, Hunt AN. Dynamic lipidomics with stable isotope labelling. J Chromatogr B Analyt Technol Biomed Life Sci 2009; 877:2716-21. [DOI: 10.1016/j.jchromb.2009.03.046] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 03/29/2009] [Accepted: 03/30/2009] [Indexed: 01/22/2023]
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21
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Pace PW, Yao LJ, Wilson JX, Possmayer F, Veldhuizen RA, Lewis JF. THE EFFECTS OF HYPEROXIA EXPOSURE ON LUNG FUNCTION AND PULMONARY SURFACTANT IN A RAT MODEL OF ACUTE LUNG INJURY. Exp Lung Res 2009; 35:380-98. [DOI: 10.1080/01902140902745166] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Edwards V, Cutz E, Viero S, Moore AM, Nogee L. Ultrastructure of Lamellar Bodies in Congenital Surfactant Deficiency. Ultrastruct Pathol 2009; 29:503-9. [PMID: 16316951 DOI: 10.1080/01913120500323480] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Congenital surfactant deficiency (CSD) is a newly identified neonatal lung disorder associated with a variety of molecular defects affecting surfactant synthesis and secretion in alveolar type II cells. The authors present ultrastructural findings of abnormal lamellar bodies in lung biopsies from 4 infants with CSD. All were term infants presenting shortly after birth with severe respiratory failure that was unresponsive to conventional therapy and all died within the first month of life. Lung biopsies were performed between 8 and 25 days of age. Biochemical and molecular studies in 2 unrelated male infants identified SP-B deficiency, one case with 121 ins 2 mutation and the second with a 209 + 4 A > G mutation. Light microscopy in both cases showed features of alveolar proteinosis. Ultrastructurally, alveolar type II cells lacked mature lamellar bodies, and their cytoplasm contained numerous pleomorphic inclusions with membranous and vesicular structures not seen in normal type II cells. The other 2 infants were a pair of siblings in whom molecular studies identified mutations in ABCA3 transporter gene. Light microscopy showed features of acinar dysplasia and desquamative interstitial pneumonitis. TEM studies revealed absence of mature lamellar bodies in type II cells and instead showed a mixture of cytoplasmic electron-dense inclusions with concentric membranes and distinctive electron dense aggregates. The ultrastructural changes in alveolar type II cells correlated well with specific gene defect. In SP-B deficiency, the absence of mature lamellar bodies is consistent with the postulated role for this protein in the formation of lamellar bodies. The lack of mature lamellar bodies in the ABCA3 gene mutations is due to the dysfunction of this endogenous lipid transporter that targets surfactant lipid moieties to the lamellar bodies. The findings demonstrate the importance of TEM studies of lung biopsies from infants with CSD as it is a critical adjunct in the diagnosis of neonatal lung disease and in defining the underlying cellular defects.
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Affiliation(s)
- V Edwards
- Division of Pathology, Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
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23
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Spyridakis S, Leondaritis G, Nakos G, Lekka ME, Galanopoulou D. A specific phospholipase C activity regulates phosphatidylinositol levels in lung surfactant of patients with acute respiratory distress syndrome. Am J Respir Cell Mol Biol 2009; 42:357-62. [PMID: 19491339 DOI: 10.1165/rcmb.2009-0078oc] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Lung surfactant (LS) is a lipid-rich material lining the inside of the lungs. It reduces surface tension at the liquid/air interface and thus, it confers protection of the alveoli from collapsing. The surface-active component of LS is dipalmitoyl-phosphatidylcholine, while anionic phospholipids such as phosphatidylinositol (PtdIns) and primarily phosphatidylglycerol are involved in the stabilization of the LS monolayer. The exact role of PtdIns in this system is not well-understood; however, PtdIns levels change dramatically during the acute respiratory distress syndrome (ARDS) evolution. In this report we present evidence of a phosphoinositide-specific phospholipase C (PI-PLC) activity in bronchoalveolar lavage (BAL) fluid, which may regulate PtdIns levels. Characterization of this extracellular activity showed specificity for PtdIns and phosphatidylinositol 4,5-bisphosphate, sharing the typical substrate concentration-, pH-, and calcium-dependencies with mammalian PI-PLCs. Fractionation of BAL fluid showed that PI-PLC did not co-fractionate with large surfactant aggregates, but it was found mainly in the soluble fraction. Importantly, analysis of BAL samples from control subjects and from patients with ARDS showed that the PI-PLC specific activity was decreased by 4-fold in ARDS samples concurrently with the increase in BAL PtdIns levels. Thus, we have identified for the first time an extracellular PI-PLC enzyme activity that may be acutely involved in the regulation of PtdIns levels in LS.
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Affiliation(s)
- Spyros Spyridakis
- Department of Chemistry, University of Athens, Zografou, 15771 Athens, Greece
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24
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Christmann U, Hite R, Witonsky S, Elvinger F, Werre S, Thatcher C, Tan R, Buechner-Maxwell V. Influence of Age on Surfactant Isolated from Healthy Horses Maintained on Pasture. J Vet Intern Med 2009; 23:612-8. [DOI: 10.1111/j.1939-1676.2009.0298.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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Gahlot L, Green FHY, Rigaux A, Schneider JM, Hasan SU. Role of vagal innervation on pulmonary surfactant system during fetal development. J Appl Physiol (1985) 2009; 106:1641-9. [DOI: 10.1152/japplphysiol.90868.2008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Vagally mediated afferent feedback and compliant lungs (surfactant system) play vital roles in the establishment of adequate alveolar ventilation and pulmonary gas exchange at birth. Although the significance of vagal innervation in the establishment of normal breathing patterns is well recognized, the precise role of lung innervation in the maturation of the surfactant system remains unclear. The specific aim of the present study was to investigate whether vagal denervation compromises the surfactant system during fetal development. Experiments were performed on 12 time-dated fetal sheep: 8 underwent cervical vagal denervation, and 4 were sham operated. Vagal denervation was performed at 110–113 days gestation. Fetal lambs were instrumented in utero to record arterial pH and blood-gas tensions. The animals were delivered by cesarean section under general anesthesia between 130 and 133 days gestation (term ∼147 days). Lung samples were collected for wet-to-dry ratios, light and electron microscopy, and overall lung morphology. In addition, total proteins, total phospholipids, and surfactant proteins A and B were analyzed in both lung tissue and bronchoalveolar lavage fluid. Vagal denervation had no effect on alveolar architecture, including type II cells or the morphology of lamellar bodies within them. Furthermore, surfactant proteins A and B and total phospholipids were similar in lung tissue and bronchoalveolar lavage fluid between the two groups. A significant correlation was observed between circulating cortisol concentrations and surfactant proteins in the bronchoalveolar lavage fluid and lung tissue. We provide definitive evidence that vagal innervation at midgestation is not required for maturation of the pulmonary surfactant system during fetal development.
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26
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Liu W, Volpe MAV, Zscheppang K, Nielsen HC, Dammann CEL. ErbB4 regulates surfactant synthesis and proliferation in adult rat pulmonary epithelial cells. Exp Lung Res 2009; 35:29-47. [PMID: 19191103 DOI: 10.1080/01902140802395757] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
ErbB4 is a predominant heterodimer for other ErbB receptors in late fetal lung development where it participates in regulating type II cell surfactant synthesis. To further elucidate the role of ErbB4 in pulmonary alveolar epithelial cell function, the authors hypothesized that ErbB4 participates in maintaining adult lung type II cell homeostasis. The authors used small interfering RNA (siRNA) to down-regulate endogenous, ErbB4 receptors in the adult rat lung epithelial L2 cell line and measured neuregulin 1beta (NRG1beta)-, and fibroblast conditioned medium (FCM)-induced effects on L2 cell surfactant phospholipid synthesis and proliferation. Under control conditions, total and phosphorylated ErbB4 were significantly increased after both NRG1beta and FCM treatment, as were surfactant phospholipids synthesis and cell proliferation. Down-regulation of ErbB4 with siRNA reduced stimulation of NRG1beta- and FCM-induced ErbB4 phosphorylation, decreased endogenous surfactant phospholipid synthesis, and blocked NRG1beta- and FCM-stimulated surfactant phospholipid synthesis. NRG1beta- and FCM-induced cell proliferation was not affected. The authors conclude that ErbB4 participates in maintaining adult lung alveolar epithelial cell surfactant synthesis and proliferation with development-specific functions.
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Affiliation(s)
- Washa Liu
- Newborn Medicine, Department of Pediatrics, Floating Hospital for Children at Tufts Medical Center, Boston, Massachusetts 02111, USA.
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27
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Christmann U, Buechner-Maxwell VA, Witonsky SG, Hite RD. Role of lung surfactant in respiratory disease: current knowledge in large animal medicine. J Vet Intern Med 2009; 23:227-42. [PMID: 19192153 DOI: 10.1111/j.1939-1676.2008.0269.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Lung surfactant is produced by type II alveolar cells as a mixture of phospholipids, surfactant proteins, and neutral lipids. Surfactant lowers alveolar surface tension and is crucial for the prevention of alveolar collapse. In addition, surfactant contributes to smaller airway patency and improves mucociliary clearance. Surfactant-specific proteins are part of the innate immune defense mechanisms of the lung. Lung surfactant alterations have been described in a number of respiratory diseases. Surfactant deficiency (quantitative deficit of surfactant) in premature animals causes neonatal respiratory distress syndrome. Surfactant dysfunction (qualitative changes in surfactant) has been implicated in the pathophysiology of acute respiratory distress syndrome and asthma. Analysis of surfactant from amniotic fluid allows assessment of fetal lung maturity (FLM) in the human fetus and exogenous surfactant replacement therapy is part of the standard care in premature human infants. In contrast to human medicine, use and success of FLM testing or surfactant replacement therapy remain limited in veterinary medicine. Lung surfactant has been studied in large animal models of human disease. However, only a few reports exist on lung surfactant alterations in naturally occurring respiratory disease in large animals. This article gives a general review on the role of lung surfactant in respiratory disease followed by an overview of our current knowledge on surfactant in large animal veterinary medicine.
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Affiliation(s)
- U Christmann
- Department of Large Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Duck Pond Drive, Phase II, Blacksburg, VA 24061, USA.
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28
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Abstract
Mutations in the genes encoding the surfactant proteins B and C (SP-B and SP-C) and the phospholipid transporter, ABCA3, are associated with respiratory distress and interstitial lung disease in the pediatric population. Expression of these proteins is regulated developmentally, increasing with gestational age, and is critical for pulmonary surfactant function at birth. Pulmonary surfactant is a unique mixture of lipids and proteins that reduces surface tension at the air-liquid interface, preventing collapse of the lung at the end of expiration. SP-B and ABCA3 are required for the normal organization and packaging of surfactant phospholipids into specialized secretory organelles, known as lamellar bodies, while both SP-B and SP-C are important for adsorption of secreted surfactant phospholipids to the alveolar surface. In general, mutations in the SP-B gene SFTPB are associated with fatal respiratory distress in the neonatal period, and mutations in the SP-C gene SFTPC are more commonly associated with interstitial lung disease in older infants, children, and adults. Mutations in the ABCA3 gene are associated with both phenotypes. Despite this general classification, there is considerable overlap in the clinical and histologic characteristics of these genetic disorders. In this review, similarities and differences in the presentation of these disorders with an emphasis on their histochemical and ultrastructural features will be described, along with a brief discussion of surfactant metabolism. Mechanisms involved in the pathogenesis of lung disease caused by mutations in these genes will also be discussed.
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Affiliation(s)
- Susan E. Wert
- Perinatal Institute, Section of Neonatology, Perinatal and Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, and the Department of Pediatrics, University of Cincinnati College of Medicine, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, USA
| | - Jeffrey A. Whitsett
- Perinatal Institute, Section of Neonatology, Perinatal and Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, and the Department of Pediatrics, University of Cincinnati College of Medicine, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, USA
| | - Lawrence M. Nogee
- Division of Neonatology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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Abe A, Kelly R, Kollmeyer J, Hiraoka M, Lu Y, Shayman JA. The secretion and uptake of lysosomal phospholipase A2 by alveolar macrophages. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2008; 181:7873-81. [PMID: 19017977 DOI: 10.4049/jimmunol.181.11.7873] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Macrophages have long been known to secrete a Phospholipase A(2) with an acidic pH optimum in response to phagocytic stimuli. However, the enzyme or enzymes responsible for this activity have not been identified. We report that mouse alveolar macrophages release lysosomal phospholipase A(2) (LPLA(2)) into the medium of cultured cells following stimulation with zymosan. The release of the enzyme was detected by enzymatic activity assays as well as by Western blotting using an Ab against mouse LPLA(2). LPLA(2) is a high mannose type glycoprotein found in lysosomes, suggesting that the released enzyme might be reincorporated into alveolar macrophages via a mannose or mannose phosphate receptor. Recombinant glycosylated mouse LPLA(2) produced by HEK293 cells was applied to LPLA(2)-deficient (LPLA(2)(-/-)) mouse alveolar macrophages. The uptake of exogenous LPLA(2) into LPLA(2)(-/-) alveolar macrophages occurred in a concentration-dependent manner. The LPLA(2) taken into the alveolar macrophages colocalized with the lysosomal marker, Lamp-1. This uptake was significantly suppressed in the presence of alpha-methyl-mannoside but not in the presence of mannose 6-phosphate. Thus, the predominant pathway for uptake of exogenous LPLA(2) is via the mannose receptor, with subsequent translocation into acidic, Lamp-1-associated compartments. LPLA(2)(-/-) alveolar macrophages are characterized by marked accumulation of phosphatidylcholine and phosphatidylethanolamine. Treatment with the recombinant LPLA(2) rescued the LPLA(2)(-/-) alveolar macrophages by markedly decreasing the phospholipid accumulation. The application of a catalytically inactive LPLA(2) revealed that the enzymatic activity of LPLA(2) was required for the phospholipid reduction. These studies identify LPLA(2) as a high m.w.-secreted Phospholipase A(2).
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Affiliation(s)
- Akira Abe
- Department of Internal Medicine, Nephrology Division, University of Michigan, Ann Arbor, MI 48109, USA
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30
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Argov N, Lemay DG, German JB. Milk Fat Globule structure & function; nanosciece comes to milk production. Trends Food Sci Technol 2008; 19:10.1016/j.tifs.2008.07.006. [PMID: 24363495 PMCID: PMC3868455 DOI: 10.1016/j.tifs.2008.07.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The biological process of fat globule assembly and secretion produces highly complex globule compositions and structures with many properties now recognized to be the direct result of these structures. During homogenization, fat globules are broken down and subsequently structures and surfaces different than the native state are formed. This process alters the milk fat globule unique macrostructure and the effects associated to their structure would be expected to be lost. In the present overview, the need for continued research of the fundamental aspects of the mechanism involved in milk fat globules synthesis secretion and size distribution, as well as establishing ways to regulate those processes are highlighted. Ultimately these insights will guide food technology to developing a new generation of structure based functional foods and as highlighted in this overview, dairy functional products should be the pioneering commodity.
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Affiliation(s)
- Nurit Argov
- Department of food Science and Technology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, United States
| | - Danielle G Lemay
- Department of food Science and Technology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, United States
| | - J Bruce German
- Department of food Science and Technology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, United States
- Nestle Research Center, Lausanne, Switzerland
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31
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Zuo YY, Veldhuizen RAW, Neumann AW, Petersen NO, Possmayer F. Current perspectives in pulmonary surfactant--inhibition, enhancement and evaluation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:1947-77. [PMID: 18433715 DOI: 10.1016/j.bbamem.2008.03.021] [Citation(s) in RCA: 361] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 03/26/2008] [Accepted: 03/26/2008] [Indexed: 02/06/2023]
Abstract
Pulmonary surfactant (PS) is a complicated mixture of approximately 90% lipids and 10% proteins. It plays an important role in maintaining normal respiratory mechanics by reducing alveolar surface tension to near-zero values. Supplementing exogenous surfactant to newborns suffering from respiratory distress syndrome (RDS), a leading cause of perinatal mortality, has completely altered neonatal care in industrialized countries. Surfactant therapy has also been applied to the acute respiratory distress syndrome (ARDS) but with only limited success. Biophysical studies suggest that surfactant inhibition is partially responsible for this unsatisfactory performance. This paper reviews the biophysical properties of functional and dysfunctional PS. The biophysical properties of PS are further limited to surface activity, i.e., properties related to highly dynamic and very low surface tensions. Three main perspectives are reviewed. (1) How does PS permit both rapid adsorption and the ability to reach very low surface tensions? (2) How is PS inactivated by different inhibitory substances and how can this inhibition be counteracted? A recent research focus of using water-soluble polymers as additives to enhance the surface activity of clinical PS and to overcome inhibition is extensively discussed. (3) Which in vivo, in situ, and in vitro methods are available for evaluating the surface activity of PS and what are their relative merits? A better understanding of the biophysical properties of functional and dysfunctional PS is important for the further development of surfactant therapy, especially for its potential application in ARDS.
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Affiliation(s)
- Yi Y Zuo
- Department of Biochemistry, University of Western Ontario, London, Ontario, Canada
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32
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A comparative study of mechanisms of surfactant inhibition. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:433-44. [DOI: 10.1016/j.bbamem.2007.10.027] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Revised: 10/12/2007] [Accepted: 10/30/2007] [Indexed: 11/20/2022]
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Kang N, Policova Z, Bankian G, Hair ML, Zuo YY, Neumann AW, Acosta EJ. Interaction between chitosan and bovine lung extract surfactants. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:291-302. [DOI: 10.1016/j.bbamem.2007.10.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2007] [Revised: 09/27/2007] [Accepted: 10/02/2007] [Indexed: 11/28/2022]
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Schmiedl A, Vieten G, Mühlfeld C, Bernhard W. Distribution of intracellular and secreted surfactant during postnatal rat lung development. Pediatr Pulmonol 2007; 42:548-62. [PMID: 17469149 DOI: 10.1002/ppul.20623] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Pulmonary surfactant prevents alveolar collapse via reduction of surface tension. In contrast to human neonates, rats are born with saccular lungs. Therefore, rat lungs serve as a model for investigation of the surfactant system during postnatal alveolar formation. We hypothesized that this process is associated with characteristic structural and biochemical surfactant alterations. We aimed to discriminate changes related to alveolarization from those being either invariable or follow continuous patterns of postnatal changes. Secreted active (mainly tubular myelin (tm)) and inactive (unilamellar vesicles (ulv)) surfactant subtypes as well as intracellular surfactant (lamellar bodies (lb)) in type II pneumocytes (PNII) were quantified before (day (d) 1), during (d 7), at the end of alveolarization (d 14), and after completion of lung maturation (d 42) using electron microscopic methods supplemented by biochemical analyses (phospholipid quantification, immunoblotting for SP-A). Immunoelectron microscopy determined the localization of surfactant protein A (SP-A). (1) At d 1 secreted surfactant was increased relative to d 7-42 and then decreased significantly. (2) Air spaces of neonatal lungs comprised lower fractions of tm and increased ulv, which correlated with low SP-A concentrations in lung lavage fluid (LLF) and increased respiratory rates, respectively. (3) Alveolarization (d 7-14) was associated with decreasing PNII size although volume and sizes of Lb continuously increased. (4) The volume fractions of Lb correlated well with the pool sizes of phospholipids in lavaged lungs. Our study emphasizes differential patterns of developmental changes of the surfactant system relative to postnatal alveolarization.
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Affiliation(s)
- Andreas Schmiedl
- Department of Anatomy, Hannover Medical School, Hannover, Germany.
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Galván EM, Chen H, Schifferli DM. The Psa fimbriae of Yersinia pestis interact with phosphatidylcholine on alveolar epithelial cells and pulmonary surfactant. Infect Immun 2006; 75:1272-9. [PMID: 17178780 PMCID: PMC1828548 DOI: 10.1128/iai.01153-06] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pH 6 antigen (Psa) of Yersinia pestis consists of fimbriae with adhesive properties of potential importance for the pathogenesis of plague, including pneumonic plague. The Psa fimbriae mediate bacterial binding to human alveolar epithelial cells. The Psa fimbriae bound mostly to one component present in the total lipid extract from type II alveolar epithelial cells of the cell line A549 separated by thin-layer chromatography (TLC). The Psa receptor was identified as phosphatidylcholine (PC) by TLC using alkali treatment, molybdenum blue staining, and Psa overlays. The Psa fimbriae bound to PC in a dose-dependent manner, and binding was inhibited by phosphorylcholine (ChoP) and choline. Binding inhibition was dose dependent, although only high concentrations of ChoP completely blocked Psa binding to PC. In contrast, less than 1 muM of a ChoP-polylysine polymer inhibited specifically the adhesion of Psa-fimbriated Escherichia coli to PC, and type I (WI-26 VA4) and type II alveolar epithelial cells. These results indicated that the homopolymeric Psa fimbriae are multimeric adhesins. Psa also bound to pulmonary surfactant, which covers the alveolar surface as a product of type II alveolar epithelial cells and includes PC as the major component. The observed dose-dependent interaction of Psa with pulmonary surfactant was blocked by ChoP. Interestingly, surfactant did not inhibit Psa-mediated bacterial binding to alveolar cells, suggesting that both surfactant and cell membrane PC retain Psa-fimbriated bacteria on the alveolar surface. Altogether, the results indicate that Psa uses the ChoP moiety of PC as a receptor to mediate bacterial binding to pulmonary surfactant and alveolar epithelial cells.
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Affiliation(s)
- Estela M Galván
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, 3800 Spruce St., Philadelphia, PA 19104, USA
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Burkhardt O, Lode H, Welte T, Merker HJ. Ultrastructural types of alveolar macrophages in bronchoalveolar lavages from patients with pulmonary sarcoidosis. Micron 2006; 38:572-9. [PMID: 17127071 DOI: 10.1016/j.micron.2006.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2006] [Revised: 10/30/2006] [Accepted: 10/30/2006] [Indexed: 10/23/2022]
Abstract
By routine applied quantitative BAL methods are particularly helpful for the diagnosis of pulmonary sarcoidosis. Here the morphology of the alveolar cells does not play a role. However, morphological and especially electron microscopic investigations might contribute to the clarification of the aetiology of this disease. In a prospective study we investigated the bronchoalveolar lavages (BALs) from 10 patients with recently histologically diagnosed, untreated pulmonary sarcoidosis. Commonly applied cytological and immunological BAL diagnostic techniques were accompanied by morphological investigations of alveolar cells, especially alveolar macrophages, using light and electron microscopy. All patients showed lymphocytic alveolitis with an increased number of CD4 positive lymphocytes as well as an increased CD4/CD8 ratio. A striking light microscopic finding was the great morphological variety of the alveolar macrophages. Electron microscopy revealed typical lymphocytes, neutrophils, and eosinophils as well as three different types of alveolar macrophages in all 10 patients: type I (approx. 30%) with a normal macrophage morphology, a vacuole-rich type II (approx. 30%) with myelin-like structures and type III (approx. 40%) with electron-dense inclusions. The occurrence of intracellular myelin figures in type II macrophages is a hint for increased phagocytotic processes of surfactant with or without its overproduction in the sense of a secondary alveolar proteinosis. Numerous electron-dense inclusions in type III also indicate an increased macrophage activity that leads to an increased release of cytokines, which in turn can trigger an inflammatory reaction.
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Affiliation(s)
- Olaf Burkhardt
- Department of Chest and Infectious Diseases, Chest Hospital Heckeshorn, Berlin, Germany.
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Chen X, Hyatt BA, Mucenski ML, Mason RJ, Shannon JM. Identification and characterization of a lysophosphatidylcholine acyltransferase in alveolar type II cells. Proc Natl Acad Sci U S A 2006; 103:11724-9. [PMID: 16864775 PMCID: PMC1544237 DOI: 10.1073/pnas.0604946103] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pulmonary surfactant is a complex of lipids and proteins produced and secreted by alveolar type II cells that provides the low surface tension at the air-liquid interface. The phospholipid most responsible for providing the low surface tension in the lung is dipalmitoylphosphatidylcholine. Dipalmitoylphosphatidylcholine is synthesized in large part by phosphatidylcholine (PC) remodeling, and a lysophosphatidylcholine (lysoPC) acyltransferase is thought to play a critical role in its synthesis. However, this acyltransferase has not yet been identified. We have cloned full-length rat and mouse cDNAs coding for a lysoPC acyltransferase (LPCAT). LPCAT encodes a 535-aa protein of approximately 59 kDa that contains a transmembrane domain and a putative acyltransferase domain. When transfected into COS-7 cells and HEK293 cells, LPCAT significantly increased lysoPC acyltransferase activity. LPCAT preferred lysoPC as a substrate over lysoPA, lysoPI, lysoPS, lysoPE, or lysoPG and prefers palmitoyl-CoA to oleoyl-CoA as the acyl donor. This LPCAT was preferentially expressed in the lung, specifically within alveolar type II cells. Expression in the fetal lung and in rat type II cells correlated with the expression of the surfactant proteins. LPCAT expression in fetal lung explants was sensitive to dexamethasone and FGFs. KGF was a potent stimulator of LPCAT expression in cultured adult type II cells. We hypothesize that LPCAT plays a critical role in regulating surfactant phospholipid biosynthesis and suggest that understanding the regulation of LPCAT will offer important insight into surfactant phospholipid biosynthesis.
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Affiliation(s)
- Xueni Chen
- *Department of Medicine, National Jewish Medical and Research Center, 1400 Jackson Street, Denver, CO 80206
| | - Brian A. Hyatt
- Department of Biology, Bethel University, 3900 Bethel Drive, St. Paul, MN 55112; and
| | - Michael L. Mucenski
- Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229-3039
| | - Robert J. Mason
- *Department of Medicine, National Jewish Medical and Research Center, 1400 Jackson Street, Denver, CO 80206
- To whom correspondence should be addressed. E-mail:
| | - John M. Shannon
- Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229-3039
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Kaminski WE, Piehler A, Wenzel JJ. ABC A-subfamily transporters: Structure, function and disease. Biochim Biophys Acta Mol Basis Dis 2006; 1762:510-24. [PMID: 16540294 DOI: 10.1016/j.bbadis.2006.01.011] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2005] [Revised: 01/30/2006] [Accepted: 01/31/2006] [Indexed: 12/01/2022]
Abstract
ABC transporters constitute a family of evolutionarily highly conserved multispan proteins that mediate the translocation of defined substrates across membrane barriers. Evidence has accumulated during the past years to suggest that a subgroup of 12 structurally related "full-size" transporters, referred to as ABC A-subfamily transporters, mediates the transport of a variety of physiologic lipid compounds. The emerging importance of ABC A-transporters in human disease is reflected by the fact that as yet four members of this protein family (ABCA1, ABCA3, ABCR/ABCA4, ABCA12) have been causatively linked to completely unrelated groups of monogenetic disorders including familial high-density lipoprotein (HDL) deficiency, neonatal surfactant deficiency, degenerative retinopathies and congenital keratinization disorders. Although the biological function of the remaining 8 ABC A-transporters currently awaits clarification, they represent promising candidate genes for a presumably equally heterogenous group of Mendelian diseases associated with perturbed cellular lipid transport. This review summarizes our current knowledge on the role of ABC A-subfamily transporters in physiology and disease and explores clinical entities which may be potentially associated with dysfunctional members of this gene subfamily.
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Affiliation(s)
- Wolfgang E Kaminski
- Institute for Clinical Chemistry, Faculty for Clinical Medicine Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
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