1
|
Hamvas A, Chaudhari BP, Nogee LM. Genetic testing for diffuse lung diseases in children. Pediatr Pulmonol 2023. [PMID: 37191361 DOI: 10.1002/ppul.26447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 04/04/2023] [Accepted: 04/23/2023] [Indexed: 05/17/2023]
Abstract
Newly developing genomic technologies are an increasingly important part of clinical care and thus, it is not only important to understand the technologies and their limitations, but to also interpret the findings in an actionable fashion. Clinical geneticists and genetic counselors are now an integral part of the clinical team and are able to bridge the complexities of this rapidly changing science between the bedside clinicians and patients. This manuscript reviews the terminology, the current technology, some of the known genetic disorders that result in lung disease, and indications for genetic testing with associated caveats. Because this field is evolving quickly, we also provide links to websites that provide continuously updated information important for integrating genomic technology results into clinical decision-making.
Collapse
Affiliation(s)
- Aaron Hamvas
- Department of Pediatrics, Division of Neonatology, Ann and Robert H. Lurie Children's Hospital of Chicago and Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Bimal P Chaudhari
- Divisions of Genetics and Genomic Medicine, Neonatology, Nationwide Children's Hospital, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Lawrence M Nogee
- Department of Pediatrics, Eudowood Neonatal Pulmonary Division, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
2
|
Chen T, Li G, Liu W, Fan Z, Li L. Surfactant Protein A Can Affect Macrophage Phagocytosis: An Important Pathogenic Mechanism of Otitis Media with Effusion. J Assoc Res Otolaryngol 2023; 24:171-180. [PMID: 36820988 PMCID: PMC10121950 DOI: 10.1007/s10162-023-00893-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 02/10/2023] [Indexed: 02/24/2023] Open
Abstract
Otitis media with effusion (OME), also known as secretory otitis media, is a common condition in otorhinolaryngology. The main manifestations include middle ear effusion and conductive hearing loss. Recently, increasing attention has been paid to the etiology of OME, wherein immune dysfunction is one important pathogenic mechanism. However, it is unknown whether changes in surfactant protein A (SPA) secretion affect the phagocytic activity of macrophages in the Eustachian tube, thereby altering pathogen clearance, during the pathogenesis of OME. In our study, an OME animal model was established and evaluated. Differences in SPA levels in Eustachian tube lavage fluid between the experimental and control groups were analyzed. Cell-based experiments revealed that SPA decreased the expression of CD64 and SYK and inhibited phagocytosis by RAW264.7 cells. By using flow cytometry and immunofluorescence, we confirmed that macrophage phagocytosis decreased with increasing SPA levels. Finally, we concluded that SPA affects macrophage function and plays a role in the occurrence and development of OME.
Collapse
Affiliation(s)
- Tao Chen
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Shandong University, No. 4, Duanxing West Road, Huaiyin District, Jinan, 250023, China
- Department of Otolaryngology, Shenzhen Second People's Hospital/The First Affiliated Hospital of Shenzhen University, Shenzhen, China
| | - Guodong Li
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Shandong University, No. 4, Duanxing West Road, Huaiyin District, Jinan, 250023, China
- Department of Otolaryngology, Shanxi Provincial People's Hospital/The Fifth Clinical Medical College of Shanxi Medical University, Taiyuan, China
| | - Wenwen Liu
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Shandong University, No. 4, Duanxing West Road, Huaiyin District, Jinan, 250023, China
| | - Zhaomin Fan
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Shandong University, No. 4, Duanxing West Road, Huaiyin District, Jinan, 250023, China
| | - Li Li
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Shandong University, No. 4, Duanxing West Road, Huaiyin District, Jinan, 250023, China.
| |
Collapse
|
3
|
Pioselli B, Salomone F, Mazzola G, Amidani D, Sgarbi E, Amadei F, Murgia X, Catinella S, Villetti G, De Luca D, Carnielli V, Civelli M. Pulmonary surfactant: a unique biomaterial with life-saving therapeutic applications. Curr Med Chem 2021; 29:526-590. [PMID: 34525915 DOI: 10.2174/0929867328666210825110421] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 06/26/2021] [Accepted: 06/29/2021] [Indexed: 11/22/2022]
Abstract
Pulmonary surfactant is a complex lipoprotein mixture secreted into the alveolar lumen by type 2 pneumocytes, which is composed by tens of different lipids (approximately 90% of its entire mass) and surfactant proteins (approximately 10% of the mass). It is crucially involved in maintaining lung homeostasis by reducing the values of alveolar liquid surface tension close to zero at end-expiration, thereby avoiding the alveolar collapse, and assembling a chemical and physical barrier against inhaled pathogens. A deficient amount of surfactant or its functional inactivation is directly linked to a wide range of lung pathologies, including the neonatal respiratory distress syndrome. This paper reviews the main biophysical concepts of surfactant activity and its inactivation mechanisms, and describes the past, present and future roles of surfactant replacement therapy, focusing on the exogenous surfactant preparations marketed worldwide and new formulations under development. The closing section describes the pulmonary surfactant in the context of drug delivery. Thanks to its peculiar composition, biocompatibility, and alveolar spreading capability, the surfactant may work not only as a shuttle to the branched anatomy of the lung for other drugs but also as a modulator for their release, opening to innovative therapeutic avenues for the treatment of several respiratory diseases.
Collapse
Affiliation(s)
| | | | | | | | - Elisa Sgarbi
- Preclinical R&D, Chiesi Farmaceutici, Parma. Italy
| | | | - Xabi Murgia
- Department of Biotechnology, GAIKER Technology Centre, Zamudio. Spain
| | | | | | - Daniele De Luca
- Division of Pediatrics and Neonatal Critical Care, Antoine Béclère Medical Center, APHP, South Paris University Hospitals, Paris, France; Physiopathology and Therapeutic Innovation Unit-U999, South Paris-Saclay University, Paris. France
| | - Virgilio Carnielli
- Division of Neonatology, G Salesi Women and Children's Hospital, Polytechnical University of Marche, Ancona. Italy
| | | |
Collapse
|
4
|
Bush A, Pabary R. Pulmonary alveolarproteinosis in children. Breathe (Sheff) 2020; 16:200001. [PMID: 32684993 PMCID: PMC7341618 DOI: 10.1183/20734735.0001-2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 03/01/2020] [Indexed: 12/15/2022] Open
Abstract
Pulmonary alveolar proteinosis (PAP) is an umbrella term for a wide spectrum of conditions that have a very characteristic appearance on computed tomography. There is outlining of the secondary pulmonary lobules on the background of ground-glass shadowing and pathologically, filling of the alveolar spaces with normal or abnormal surfactant. PAP is rare and the common causes in children are very different from those seen in adults; autoimmune PAP is rare and macrophage blockade not described in children. There are many genetic causes of PAP, the best known of which are mutations in the genes encoding surfactant protein (SP)-B, SP-C, thyroid transcription factor 1, ATP-binding cassette protein 3, and the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor α- and β- chains. PAP may also be a manifestation of rheumatological and metabolic disease, congenital immunodeficiency, and haematological malignancy. Precise diagnosis of the underlying cause is essential in planning treatment, as well as for genetic counselling. The evidence base for treatment is poor. Some forms of PAP respond well to whole-lung lavage, and autoimmune PAP, which is much commoner in adults, responds to inhaled or subcutaneous GM-CSF. Emerging therapies based on studies in murine models of PAP include stem-cell transplantation for GM-CSF receptor mutations. EDUCATIONAL AIMS To understand when to suspect that a child has pulmonary alveolar proteinosis (PAP) and how to confirm that this is the cause of the presentation.To show that PAP is an umbrella term for conditions characterised by alveolar filling by normal or abnormal surfactant, and that this term is the start, not the end, of the diagnostic journey.To review the developmental differences in the spectrum of conditions that may cause PAP, and specifically to understand the differences between causes in adults and children.To discuss when to treat PAP with whole-lung lavage and/or granulocyte-macrophage colony-stimulating factor, and review potential promising new therapies.
Collapse
Affiliation(s)
- Andrew Bush
- Imperial College, London, UK
- Royal Brompton Harefield NHS Foundation Trust, London, UK
| | - Rishi Pabary
- Imperial College, London, UK
- Royal Brompton Harefield NHS Foundation Trust, London, UK
| |
Collapse
|
5
|
Lipid-Protein and Protein-Protein Interactions in the Pulmonary Surfactant System and Their Role in Lung Homeostasis. Int J Mol Sci 2020; 21:ijms21103708. [PMID: 32466119 PMCID: PMC7279303 DOI: 10.3390/ijms21103708] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 12/12/2022] Open
Abstract
Pulmonary surfactant is a lipid/protein complex synthesized by the alveolar epithelium and secreted into the airspaces, where it coats and protects the large respiratory air–liquid interface. Surfactant, assembled as a complex network of membranous structures, integrates elements in charge of reducing surface tension to a minimum along the breathing cycle, thus maintaining a large surface open to gas exchange and also protecting the lung and the body from the entrance of a myriad of potentially pathogenic entities. Different molecules in the surfactant establish a multivalent crosstalk with the epithelium, the immune system and the lung microbiota, constituting a crucial platform to sustain homeostasis, under health and disease. This review summarizes some of the most important molecules and interactions within lung surfactant and how multiple lipid–protein and protein–protein interactions contribute to the proper maintenance of an operative respiratory surface.
Collapse
|
6
|
Albert RK, Smith B, Perlman CE, Schwartz DA. Is Progression of Pulmonary Fibrosis due to Ventilation-induced Lung Injury? Am J Respir Crit Care Med 2019; 200:140-151. [PMID: 31022350 PMCID: PMC6635778 DOI: 10.1164/rccm.201903-0497pp] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/22/2019] [Indexed: 02/06/2023] Open
Affiliation(s)
| | - Bradford Smith
- Department of Bioengineering, University of Colorado, Aurora, Colorado; and
| | - Carrie E. Perlman
- Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey
| | | |
Collapse
|
7
|
Abstract
PURPOSE OF REVIEW Mutations in genes encoding proteins critical for the production and function of pulmonary surfactant cause diffuse lung disease. Timely recognition and diagnosis of affected individuals is important for proper counseling concerning prognosis and recurrence risk. RECENT FINDINGS Involved genes include those encoding for surfactant proteins A, B, and C, member A3 of the ATP-binding cassette family, and for thyroid transcription factor 1. Clinical presentations overlap and range from severe and rapidly fatal neonatal lung disease to development of pulmonary fibrosis well into adult life. The inheritance patterns, course, and prognosis differ depending upon the gene involved, and in some cases the specific mutation. Treatment options are currently limited, with lung transplantation an option for patients with end-stage pulmonary fibrosis. Additional genetic disorders with overlapping pulmonary phenotypes are being identified through newer methods, although these disorders often involve other organ systems. SUMMARY Genetic disorders of surfactant production are rare but associated with significant morbidity and mortality. Diagnosis can be made invasively through clinically available genetic testing. Improved treatment options are needed and better understanding of the molecular pathophysiology may provide insights into treatments for other lung disorders causing fibrosis.
Collapse
Affiliation(s)
- Lawrence M Nogee
- Eudowood Neonatal Pulmonary Division, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
8
|
Jacob A, Morley M, Hawkins F, McCauley KB, Jean JC, Heins H, Na CL, Weaver TE, Vedaie M, Hurley K, Hinds A, Russo SJ, Kook S, Zacharias W, Ochs M, Traber K, Quinton LJ, Crane A, Davis BR, White FV, Wambach J, Whitsett JA, Cole FS, Morrisey EE, Guttentag SH, Beers MF, Kotton DN. Differentiation of Human Pluripotent Stem Cells into Functional Lung Alveolar Epithelial Cells. Cell Stem Cell 2017; 21:472-488.e10. [PMID: 28965766 PMCID: PMC5755620 DOI: 10.1016/j.stem.2017.08.014] [Citation(s) in RCA: 330] [Impact Index Per Article: 47.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 06/21/2017] [Accepted: 08/18/2017] [Indexed: 02/01/2023]
Abstract
Lung alveoli, which are unique to air-breathing organisms, have been challenging to generate from pluripotent stem cells (PSCs) in part because there are limited model systems available to provide the necessary developmental roadmaps for in vitro differentiation. Here we report the generation of alveolar epithelial type 2 cells (AEC2s), the facultative progenitors of lung alveoli, from human PSCs. Using multicolored fluorescent reporter lines, we track and purify human SFTPC+ alveolar progenitors as they emerge from endodermal precursors in response to stimulation of Wnt and FGF signaling. Purified PSC-derived SFTPC+ cells form monolayered epithelial "alveolospheres" in 3D cultures without the need for mesenchymal support, exhibit self-renewal capacity, and display additional AEC2 functional capacities. Footprint-free CRISPR-based gene correction of PSCs derived from patients carrying a homozygous surfactant mutation (SFTPB121ins2) restores surfactant processing in AEC2s. Thus, PSC-derived AEC2s provide a platform for disease modeling and future functional regeneration of the distal lung.
Collapse
Affiliation(s)
- Anjali Jacob
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA; The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Michael Morley
- Penn Center for Pulmonary Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Finn Hawkins
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA; The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Katherine B McCauley
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA; The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - J C Jean
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA; The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Hillary Heins
- Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Cheng-Lun Na
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Timothy E Weaver
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Marall Vedaie
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA; The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Killian Hurley
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA; The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Anne Hinds
- The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Scott J Russo
- Penn Center for Pulmonary Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Seunghyi Kook
- Department of Pediatrics, Monroe Carell Jr. Children's Hospital, Vanderbilt University, Nashville, TN 37232, USA
| | - William Zacharias
- Penn Center for Pulmonary Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Matthias Ochs
- Institute of Functional and Applied Anatomy, Hannover Medical School, Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), REBIRTH Cluster of Excellence, 30625 Hannover, Germany
| | - Katrina Traber
- The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Lee J Quinton
- The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Ana Crane
- Center for Stem Cell and Regenerative Medicine, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Brian R Davis
- Center for Stem Cell and Regenerative Medicine, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Frances V White
- Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jennifer Wambach
- Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jeffrey A Whitsett
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - F Sessions Cole
- Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Edward E Morrisey
- Penn Center for Pulmonary Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Susan H Guttentag
- Department of Pediatrics, Monroe Carell Jr. Children's Hospital, Vanderbilt University, Nashville, TN 37232, USA
| | - Michael F Beers
- Penn Center for Pulmonary Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Darrell N Kotton
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA; The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA.
| |
Collapse
|
9
|
Chaby R, Garcia-Verdugo I, Espinassous Q, Augusto LA. Interactions between LPS and lung surfactant proteins. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519050110030701] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
After penetration into the lower airways, bacterial lipopolysaccharide (LPS) interacts with alveolar cells in a fluid environment consisting of pulmonary surfactant, a lipid—protein complex which prevents alveolar collapsing and participates in lung defense. The two hydrophilic surfactant components SP-A and SP-D are proteins with collagen-like and lectin domains (collectins) able to interact with carbohydrate-containing ligands present on microbial membranes, and with defined regions of LPS. This explains their capacity to damage the bacterial envelope and induce an antimicrobial effect. In addition, they modulate LPS-induced production of pro-inflammatory mediators in leukocytes by interaction with LPS or with leukocyte receptors. A third surfactant component, SP-C, is a small, highly hydrophobic lipopeptide which interacts with lipid A and reduces LPS-induced effects in macrophages and splenocyte cultures. The interaction of the different SPs with CD14 might explain their ability to modulate some LPS responses. Although the alveolar fluid contains other antiLPS and antimicrobial agents, SPs are the most abundant proteins which might contribute to protect the lung epithelium and reduce the incidence of LPS-induced lung injury. The presence of the surfactant collectins SP-A and SP-D in non-pulmonary tissues, such as the female genital tract, extends their field of action to other mucosal surfaces.
Collapse
Affiliation(s)
- Richard Chaby
- Endotoxin Group, Centre National de la Recherche Scientifique, University of Paris-Sud, Orsay, France, -psud.fr
| | - Ignacio Garcia-Verdugo
- Endotoxin Group, Centre National de la Recherche Scientifique, University of Paris-Sud, Orsay, France
| | - Quentin Espinassous
- Endotoxin Group, Centre National de la Recherche Scientifique, University of Paris-Sud, Orsay, France
| | - Luis A. Augusto
- Endotoxin Group, Centre National de la Recherche Scientifique, University of Paris-Sud, Orsay, France
| |
Collapse
|
10
|
Gonzales LW, Gonzalez R, Barrette AM, Wang P, Dobbs L, Ballard PL. Expression of Carcinoembryonic Cell Adhesion Molecule 6 and Alveolar Epithelial Cell Markers in Lungs of Human Infants with Chronic Lung Disease. J Histochem Cytochem 2015; 63:908-21. [PMID: 26374831 DOI: 10.1369/0022155415603768] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 08/09/2015] [Indexed: 11/22/2022] Open
Abstract
The membrane protein carcinoembryonic antigen cell adhesion molecule (CEACAM6) is expressed in the epithelium of various tissues, participating in innate immune defense, cell proliferation and differentiation, with overexpression in gastrointestinal tract, pancreatic and lung tumors. It is developmentally and hormonally regulated in fetal human lung, with an apparent increased production in preterm infants with respiratory failure. To further examine the expression and cell localization of CEACAM6, we performed immunohistochemical and biochemical studies in lung specimens from infants with and without chronic lung disease. CEACAM6 protein and mRNA were increased ~4-fold in lungs from infants with chronic lung disease as compared with controls. By immunostaining, CEACAM6 expression was markedly increased in the lung parenchyma of infants and children with a variety of chronic lung disorders, localizing to hyperplastic epithelial cells with a ~7-fold elevated proliferative rate by PCNA staining. Some of these cells also co-expressed membrane markers of both type I and type II cells, which is not observed in normal postnatal lung, suggesting they are transitional epithelial cells. We suggest that CEACAM6 is both a marker of lung epithelial progenitor cells and a contributor to the proliferative response after injury due to its anti-apoptotic and cell adhesive properties.
Collapse
Affiliation(s)
- Linda W Gonzales
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania (LWG, PW)
| | - Robert Gonzalez
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California (RG, LD)
| | - Anne Marie Barrette
- Department of Pediatrics, University of California, San Francisco, San Francisco, California (AMB, PLB)
| | - Ping Wang
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania (LWG, PW)
| | - Leland Dobbs
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California (RG, LD)
| | - Philip L Ballard
- Department of Pediatrics, University of California, San Francisco, San Francisco, California (AMB, PLB)
| |
Collapse
|
11
|
Kurath-Koller S, Resch B, Kraschl R, Windpassinger C, Eber E. Surfactant Protein B Deficiency Caused by Homozygous C248X Mutation-A Case Report and Review of the Literature. AJP Rep 2015. [PMID: 26199800 PMCID: PMC4502623 DOI: 10.1055/s-0035-1545668] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Objective Surfactant protein B (SP-B) deficiency is a rare autosomal recessive disorder that is usually rapidly fatal. The c.397delCinsGAA mutation (121ins2) in exon 4 is found in more than two-thirds of patients. Design We report on a fatal case of SP-B deficiency caused by a homozygous C248X mutation in exon 7 of the SP-B gene. In addition, we provide an update of the current literature. The EMBASE, MEDLINE, and CINAHL databases were systematically searched to identify all papers published in the English and German literature on SP-B deficiency between 1989 and 2013. Results SP-B deficiency is characterized by progressive hypoxemic respiratory failure generally in full-term infants. They present with symptoms of respiratory distress and hypoxemia; chest X-ray resembles hyaline membrane disease. Prenatal diagnosis is possible from amniotic fluid or chorionic villi sampling. Conclusion Thirty-four mutations have been published in the literature. Treatment options are scarce. Gene therapy is hoped to be an option in the future.
Collapse
Affiliation(s)
- Stefan Kurath-Koller
- Division of General Pediatrics, Paediatric Department, Medical University of Graz, Graz, Austria
| | - Bernhard Resch
- Division of Neonatology, Paediatric Department, Research Unit for Neonatal Infectious Diseases and Epidemiology, Medical University of Graz, Graz, Austria
| | - Raimund Kraschl
- Division of Neonatology, Pediatric Department, General Hospital of Klagenfurt, Klagenfurt, Austria
| | | | - Ernst Eber
- Division of Pulmonology, Paediatric Department, Medical University of Graz, Graz, Austria
| |
Collapse
|
12
|
Li W, Lin CY, Shang C, Han P, Xiong Y, Lin CJ, Yang J, Selleri L, Chang CP. Pbx1 activates Fgf10 in the mesenchyme of developing lungs. Genesis 2014; 52:399-407. [PMID: 24591256 DOI: 10.1002/dvg.22764] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 02/20/2014] [Accepted: 02/21/2014] [Indexed: 01/19/2023]
Abstract
Insufficiency of surfactants is a core factor in respiratory distress syndrome, which causes apnea and neonatal death, particularly in preterm infants. Surfactant proteins are secreted by alveolar type II cells in the lung epithelium, the differentiation of which is regulated by Fgf10 elaborated by the adjacent mesenchyme. However, the molecular regulation of mesenchymal Fgf10 during lung development has not been fully understood. Here, we show that Pbx1, a homeodomain transcription factor, is required in the lung mesenchyme for the expression of Fgf10. Mouse embryos lacking Pbx1 in the lung mesenchyme show compact terminal saccules and perinatal lethality with failure of postnatal alveolar expansion. Mutant embryos had severely reduced expression of Fgf10 and surfactant genes (Spa, Spb, Spc, and Spd) that are essential for alveolar expansion for gas exchange at birth. Molecularly, Pbx1 directly binds to the Fgf10 promoter and cooperates with Meis and Hox proteins to transcriptionally activate Fgf10. Our results thus show how Pbx1 controls Fgf10 in the developing lung.
Collapse
Affiliation(s)
- Wei Li
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
RUCKA ZDENEK, VANHARA PETR, KOUTNA IRENA, TESAROVA LENKA, POTESILOVA MICHAELA, STEJSKAL STANISLAV, SIMARA PAVEL, DOLEZEL JAN, ZVONICEK VACLAV, COUFAL OLDRICH, CAPOV IVAN. Differential effects of insulin and dexamethasone on pulmonary surfactant-associated genes and proteins in A549 and H441 cells and lung tissue. Int J Mol Med 2013; 32:211-8. [DOI: 10.3892/ijmm.2013.1363] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Accepted: 04/10/2013] [Indexed: 11/06/2022] Open
|
14
|
Wolfson MR, Wu J, Hubert TL, Gregory TJ, Mazela J, Shaffer TH. Lucinactant attenuates pulmonary inflammatory response, preserves lung structure, and improves physiologic outcomes in a preterm lamb model of RDS. Pediatr Res 2012; 72:375-83. [PMID: 22821059 PMCID: PMC3888789 DOI: 10.1038/pr.2012.96] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Acute inflammatory responses to supplemental oxygen and mechanical ventilation have been implicated in the pathophysiological sequelae of respiratory distress syndrome (RDS). Although surfactant replacement therapy (SRT) has contributed to lung stability, the effect on lung inflammation is inconclusive. Lucinactant contains sinapultide (KL4), a novel synthetic peptide that functionally mimics surfactant protein B, a protein with anti-inflammatory properties. We tested the hypothesis that lucinactant may modulate lung inflammatory response to mechanical ventilation in the management of RDS and may confer greater protection than animal-derived surfactants. METHODS Preterm lambs (126.8 ± 0.2 SD d gestation) were randomized to receive lucinactant, poractant alfa, beractant, or no surfactant and studied for 4 h. Gas exchange and pulmonary function were assessed serially. Lung inflammation biomarkers and lung histology were assessed at termination. RESULTS SRT improved lung compliance relative to no SRT without significant difference between SRT groups. Lucinactant attenuated lung and systemic inflammatory response, supported oxygenation at lower ventilatory requirements, and preserved lung structural integrity to a greater degree than either no SRT or SRT with poractant alfa or beractant. CONCLUSION These data suggest that early intervention with lucinactant may more effectively mitigate pulmonary pathophysiological sequelae of RDS than the animal-derived surfactants poractant alfa or beractant.
Collapse
Affiliation(s)
- Marla R. Wolfson
- Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania,Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania,Departments of Pediatrics, Temple University School of Medicine, Philadelphia, Pennsylvania,Center for Inflammation, Translational, and Clinical Lung Research, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Jichuan Wu
- Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania,Center for Inflammation, Translational, and Clinical Lung Research, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Terrence L. Hubert
- Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania
| | | | - Jan Mazela
- Discovery Laboratories, Inc., Warrington, Pennsylvania,Poznan University of Medical Sciences, Poznan, Poland
| | - Thomas H. Shaffer
- Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania,Departments of Pediatrics, Temple University School of Medicine, Philadelphia, Pennsylvania,Center For Pediatric Research, Alfred I. duPont Hospital for Children, Wilmington, Delaware
| |
Collapse
|
15
|
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.
Collapse
Affiliation(s)
- Marianna Agassandian
- Department of Medicine, Acute Lung Injury Center of Excellence, the University of Pittsburgh, Pittsburgh, PA 15213, USA
| | | |
Collapse
|
16
|
Bein K, Leight H, Leikauf GD. JUN-CCAAT/enhancer-binding protein complexes inhibit surfactant-associated protein B promoter activity. Am J Respir Cell Mol Biol 2010; 45:436-44. [PMID: 21148742 DOI: 10.1165/rcmb.2010-0260oc] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The murine surfactant-associated protein B (Sftpb) gene promoter, spanning nucleotides -653 to +42, is composed of functionally distinct proximal and distal regions. Although both regions contain consensus/putative activator protein 1 (AP-1) sites, the distal, but not the proximal, region mediates the inhibition by jun proto-oncogene (JUN) of Sftpb promoter activity. In transient cotransfection assays, JUN inhibited the luciferase reporter activity of plasmid constructs containing Sftpb promoter fragments that lacked the distal putative AP-1 site, indicating that another regulatory motif mediates JUN-dependent inhibition. Electrophoretic mobility shift assays and in silico analyses identified a DNA target sequence (Sftpb nucleotides -339 to -316) and transcription factors that regulate Sftpb promoter activity. The identified sequence contains a CCAAT/enhancer-binding protein (C/EBP) consensus recognition element. Mutation of the site reduced Sftpb promoter activity and sensitivity to inhibition by JUN. Purified recombinant JUN, which did not recognize the -339 to -316 target sequence when added alone, supershifted the mobility of in vitro translated C/EBP-α and C/EBP-β proteins complexed with the identified cis-regulatory element. These findings support the idea that heterodimerization between JUN and C/EBP-α and/or C/EBP-β targets JUN to the Sftpb promoter, thereby mediating its inhibitory regulatory role.
Collapse
Affiliation(s)
- Kiflai Bein
- Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, PA 15219-3130, USA.
| | | | | |
Collapse
|
17
|
Chroneos ZC, Sever-Chroneos Z, Shepherd VL. Pulmonary surfactant: an immunological perspective. Cell Physiol Biochem 2009; 25:13-26. [PMID: 20054141 DOI: 10.1159/000272047] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2009] [Indexed: 11/19/2022] Open
Abstract
Pulmonary surfactant has two crucial roles in respiratory function; first, as a biophysical entity it reduces surface tension at the air water interface, facilitating gas exchange and alveolar stability during breathing, and, second, as an innate component of the lung's immune system it helps maintain sterility and balance immune reactions in the distal airways. Pulmonary surfactant consists of 90% lipids and 10% protein. There are four surfactant proteins named SP-A, SP-B, SP-C, and SP-D; their distinct interactions with surfactant phospholipids are necessary for the ultra-structural organization, stability, metabolism, and lowering of surface tension. In addition, SP-A and SP-D bind pathogens, inflict damage to microbial membranes, and regulate microbial phagocytosis and activation or deactivation of inflammatory responses by alveolar macrophages. SP-A and SP-D, also known as pulmonary collectins, mediate microbial phagocytosis via SP-A and SP-D receptors and the coordinated induction of other innate receptors. Several receptors (SP-R210, CD91/calreticulin, SIRPalpha, and toll-like receptors) mediate the immunological functions of SP-A and SP-D. However, accumulating evidence indicate that SP-B and SP-C and one or more lipid constituents of surfactant share similar immuno-regulatory properties as SP-A and SP-D. The present review discusses current knowledge on the interaction of surfactant with lung innate host defense.
Collapse
Affiliation(s)
- Zissis C Chroneos
- The Center of Biomedical Research, University of Texas Health Science Center at Tyler, Tyler, TX 75708-3154, USA.
| | | | | |
Collapse
|
18
|
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.
Collapse
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
| |
Collapse
|
19
|
Lyra PPR, Diniz EMDA. The importance of surfactant on the development of neonatal pulmonary diseases. Clinics (Sao Paulo) 2007; 62:181-90. [PMID: 17505704 DOI: 10.1590/s1807-59322007000200014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2006] [Accepted: 11/28/2006] [Indexed: 11/22/2022] Open
Abstract
Pulmonary surfactant is a substance composed of a lipoprotein complex that is essential to pulmonary function. Pulmonary surfactant proteins play an important role in the structure, function, and metabolism of surfactant; 4 specific surfactant proteins have been identified: surfactant proteins-A, surfactant proteins-B, surfactant proteins-C, and surfactant proteins-D. Clinical, epidemiological, and biochemical evidence suggests that the etiology of respiratory distress syndrome is multifactorial with a significant genetic component. There are reports about polymorphisms and mutations on the surfactant protein genes, especially surfactant proteins-B, that may be associated with respiratory distress syndrome, acute respiratory distress syndrome, and congenital alveolar proteinosis. Individual differences regarding respiratory distress syndrome and acute respiratory distress syndrome as well as patient response to therapy might reflect phenotypic diversity due to genetic variation, in part. The study of the differences between the allelic variants of the surfactant protein genes can contribute to the understanding of individual susceptibility to the development of several pulmonary diseases. The identification of the polymorphisms and mutations that are indeed important for the pathogenesis of the diseases related to surfactant protein dysfunction, leading to the possibility of genotyping individuals at increased risk, constitutes a new research field. In the future, findings in these endeavors may enable more effective genetic counseling as well as the development of prophylactic and therapeutic strategies that would provide a real impact on the management of newborns with respiratory distress syndrome and other pulmonary diseases.
Collapse
|
20
|
Wegner DJ, Hertzberg T, Heins HB, Elmberger G, MacCoss MJ, Carlson CS, Nogee LM, Cole FS, Hamvas A. A major deletion in the surfactant protein-B gene causing lethal respiratory distress. Acta Paediatr 2007; 96:516-20. [PMID: 17391469 DOI: 10.1111/j.1651-2227.2006.00188.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Loss of function mutations in the surfactant protein-B gene (SFTPB) cause lethal neonatal respiratory distress due to reduced or absent expression of mature surfactant protein B (SP-B, encoded in exons 6 and 7). No large deletions in SFTPB have been previously identified. AIM Genomic, proteomic and immunohistochemical characterization of a 3 kb deletion in SFTPB. METHODS A full-term newborn presented with refractory respiratory failure. We amplified and sequenced SFTPB from the infant and both parents, determined SP-B protein expression in tracheal aspirate samples using Western-blot analysis, and performed immunohistochemical staining and electron microscopy of lung biopsy tissue. RESULTS The infant was homozygous for a 2958 bp deletion in SFTPB that included exons 7 and 8. Both asymptomatic parents were heterozygous for the deletion. A truncated mature SP-B peptide was detected on Western blotting of tracheal aspirate. Amino acid sequence specific to that encoded in exon 5 was present, but that encoded by exon 7 was absent. ProSP-B expression was robust within alveolar type II cells and lamellar body structure was disrupted. CONCLUSIONS This deletion in SFTPB resulted in SP-B deficiency due to absence of elements in mature SP-B that are critical for appropriate peptide folding, trafficking and processing.
Collapse
Affiliation(s)
- Daniel J Wegner
- Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine and St. Louis Children's Hospital, MO 63110, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Abstract
Inherited disorders of pulmonary surfactant-associated proteins are rare but provide important insights into unique mechanisms of surfactant dysfunction. Recessive loss-of-function mutations in the surfactant protein-B and the ATP-binding cassette family member A3 (ABCA3) genes present as lethal surfactant deficiency in the newborn, whereas other recessive mutations in ABCA3 and dominant mutations in the surfactant protein-C gene result in interstitial lung disease in older infants and children. The molecular basis and the genetic and tissue-based approaches to the evaluation of children suspected of having one of these disorders are discussed.
Collapse
Affiliation(s)
- Aaron Hamvas
- Edward Mallinckrodt Department of Pediatrics, Washington University and St. Louis Children's Hospital, St. Louis, MO 63110, USA.
| | | | | |
Collapse
|
22
|
Almlén A, Stichtenoth G, Robertson B, Johansson J, Curstedt T. Concentration dependence of a poly-leucine surfactant protein C analogue on in vitro and in vivo surfactant activity. Neonatology 2007; 92:194-200. [PMID: 17476119 DOI: 10.1159/000102057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Accepted: 01/10/2007] [Indexed: 11/19/2022]
Abstract
BACKGROUND Modified natural surfactants currently used for treatment of respiratory distress syndrome contain about 0.5-1% (w/w phospholipids) of each of the surfactant proteins SP-B and SP-C. The supply of these preparations is limited and synthetic surfactant preparations containing lipids and peptides are under development. OBJECTIVES To investigate the potential of different concentrations of the SP-C analogue SP-C33 in 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (68:31, w/w). METHODS Surface activity was evaluated in pulsating and captive bubble surfactometers and in immature newborn rabbits. RESULTS Preparations containing >or=1% SP-C33 achieve minimum surface tension <5 mN/m indicating good biophysical activity, and increase tidal volumes in premature rabbit fetuses to the same level as a modified natural surfactant preparation does. Alveolar patency at end expiration, as evaluated by measurement of lung gas volumes, histological assessment of alveolar expansion and determination of alveolar volume density, was lower in the animals treated with synthetic surfactant than in those receiving modified natural surfactant. CONCLUSIONS These data suggest that SP-C33 is similarly efficient as the native peptide in improving surface properties of phospholipids mixtures and in increasing lung compliance in surfactant-deficient states, but that other components are needed to maintain alveolar stability at low airway pressures.
Collapse
Affiliation(s)
- Andreas Almlén
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | | | | | | | | |
Collapse
|
23
|
Hamvas A. Inherited surfactant protein-B deficiency and surfactant protein-C associated disease: clinical features and evaluation. Semin Perinatol 2006; 30:316-26. [PMID: 17142157 DOI: 10.1053/j.semperi.2005.11.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The pulmonary surfactant is a mixture of phospholipids and proteins synthesized, packaged, and secreted by alveolar type II cells that lowers surface tension and prevents atelectasis at end-expiration. A tightly regulated, complex metabolic cycle involves all components of the pulmonary surfactant. Disorders of surfactant metabolism that have a genetic basis are rare, but causes of respiratory dysfunction in infants and children emerge. Recessive loss of function mutations in surfactant protein-B (SP-B) gene lead to respiratory failure that is lethal in the newborn period while single allelic mutations in the surfactant protein-C (SP-C) gene cause interstitial lung disease of varying severity and age of onset. The genetic basis, mechanisms, clinical presentation and outcome, diagnostic approach and limited therapeutic options for disease due to mutations the SP-B and SP-C genes will be described in detail in this article. These disorders provide insights into some of the distinct mechanisms that disrupt the surfactant metabolic cycle and cause respiratory disease in infants and children.
Collapse
Affiliation(s)
- Aaron Hamvas
- Edward Mallinckrodt Department of Pediatrics, Washington University and St. Louis Children's Hospital, St. Louis, MO 63110, USA.
| |
Collapse
|
24
|
Abstract
Advances in genetic engineering have allowed the creation of animals with additional or deleted genes. New genes may be inserted in mice, specific genes inactivated or "knocked out," and more complex animals created in which genes can be turned on or off at different times in development or in different tissues. These animal models allow for more detailed studies of the proteins encoded by the manipulated gene, an improved understanding of the pathophysiology of diseases resulting from the genetic alterations, and model organisms in which to study potential new therapies. Multiple mouse models involving genes important in surfactant production and regulation relevant to lung disease observed in human newborns have been created. This review will discuss the creation of such animals and illustrate their utility in understanding human disease.
Collapse
Affiliation(s)
- Stephan W Glasser
- Division of Pulmonary Biology, Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
| | | |
Collapse
|
25
|
Abstract
Since the original description of deficiency of the pulmonary surfactant in premature newborn infants by Avery and Mead in 1959, respiratory distress syndrome has most commonly been attributed to developmental immaturity of surfactant production. Studies of different ethnic groups, gender, targeted gene ablation in murine lineages, and recent clinical reports of monogenic causes of neonatal respiratory distress syndrome have demonstrated that genetic defects disrupt pulmonary surfactant metabolism and cause respiratory distress syndrome, especially in term or near-term infants and in older infants, children, and adults. In contrast to developmental causes of respiratory distress, which may improve as infants and children mature, genetic causes result in both acute and chronic (and potentially irreversible) respiratory failure.
Collapse
Affiliation(s)
- F Sessions Cole
- Division of Newborn Medicine in the Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine and St. Louis Children's Hospital, One Children's Place, St. Louis, MO 63110, USA.
| | | | | |
Collapse
|
26
|
Abstract
Pulmonary alveolar proteinosis is a rare syndrome characterized by intra-alveolar accumulation of surfactant components and cellular debris, with minimal interstitial inflammation or fibrosis. The condition has a variable clinical course, from spontaneous resolution to respiratory failure and death due to disease progression or superimposed infections. The standard of care for alveolor proteinosis therapy is represented by whole lung lavage. Important discoveries have been made in the last decade with respect to disease pathogenesis and therapy of both congenital and acquired forms of the disease. Granulocyte-macrophage colony-stimulating factor (GM-CSF) pathway has been shown to be involved in the disease pathogenesis of both acquired and congenital disease. Furthermore, anti-GM-CSF blocking autoantibodies have been found in the serum and bronchoalveolar lavage fluid and seem to interfere with the surfactant clearance by alveolar macrophages in many acquired cases. In the congenital form, the most common defects identified to date are several mutations of the genes encoding GM-CSF receptor subunits or surfactant proteins. Using GM-CSF as a therapeutic tool has also been shown to be effective in at least half of the acquired cases treated, while the importance of quantitative determination of anti-GM-CSF antibodies before and during the course of the therapy, as well as the autoantibody titer-GM-CSF dose relationship are to be elucidated. The congenital form of the disease does not respond to therapy with GM-CSF, consistent with the known primary defects and differences in disease pathogenesis.
Collapse
Affiliation(s)
- O C Ioachimescu
- Department of Pulmonary, Allergy and Critical Care Medicine, Cleveland Clinic Foundation, A90, Cleveland, OH 44195, USA.
| | | |
Collapse
|
27
|
Brasch F, Schimanski S, Mühlfeld C, Barlage S, Langmann T, Aslanidis C, Boettcher A, Dada A, Schroten H, Mildenberger E, Prueter E, Ballmann M, Ochs M, Johnen G, Griese M, Schmitz G. Alteration of the Pulmonary Surfactant System in Full-Term Infants with Hereditary ABCA3 Deficiency. Am J Respir Crit Care Med 2006; 174:571-80. [PMID: 16728712 DOI: 10.1164/rccm.200509-1535oc] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE ABCA3 mutations are known to cause fatal surfactant deficiency. OBJECTIVE We studied ABCA3 protein expression in full-term newborns with unexplained respiratory distress syndrome (URDS) as well as the relevance of ABCA3 mutations for surfactant homeostasis. METHODS Lung tissue of infants with URDS was analyzed for the expression of ABCA3 in type II pneumocytes. Coding exons of the ABCA3 gene were sequenced. Surfactant protein expression was studied by immunohistochemistry, immunoelectron microscopy, and Western blotting. RESULTS ABCA3 protein expression was found to be greatly reduced or absent in 10 of 14 infants with URDS. Direct sequencing revealed distinct ABCA3 mutations clustering within vulnerable domains of the ABCA3 protein. A strong expression of precursors of surfactant protein B (pro-SP-B) but only low levels and aggregates of mature surfactant protein B (SP-B) within electron-dense bodies in type II pneumocytes were found. Within the matrix of electron-dense bodies, we detected precursors of SP-C (pro-SP-C) and cathepsin D. SP-A was localized in small intracellular vesicles, but not in electron-dense bodies. SP-A and pro-SP-B were shown to accumulate in the intraalveolar space, whereas mature SP-B and SP-C were reduced or absent, respectively. CONCLUSION Our data provide evidence that ABCA3 mutations are associated not only with a deficiency of ABCA3 but also with an abnormal processing and routing of SP-B and SP-C, leading to severe alterations of surfactant homeostasis and respiratory distress syndrome. To identify infants with hereditary ABCA3 deficiency, we suggest a combined diagnostic approach including immunohistochemical, ultrastructural, and mutation analysis.
Collapse
Affiliation(s)
- Frank Brasch
- Institute of Pathology, University of Bochum, Bochum
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Garmany TH, Moxley MA, White FV, Dean M, Hull WM, Whitsett JA, Nogee LM, Hamvas A. Surfactant composition and function in patients with ABCA3 mutations. Pediatr Res 2006; 59:801-5. [PMID: 16641205 DOI: 10.1203/01.pdr.0000219311.14291.df] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Mutations in the gene encoding the ATP binding cassette transporter member A3 (ABCA3) are associated with fatal surfactant deficiency. ABCA3 lines the limiting membrane of lamellar bodies within alveolar type-II cells, suggesting a role in surfactant metabolism. The objective of this study was to determine the surfactant phospholipid composition and function in patients with mutations in the ABCA3 gene. Bronchoalveolar lavage (BAL) fluid was analyzed from three groups of infants: 1) Infants with ABCA3 mutations, 2) infants with inherited surfactant protein-B deficiency (SP-B), and 3) patients without parenchymal lung disease (CON). Surfactant phospholipid profile was determined using two-dimensional thin-layer chromatography, and surface tension was measured with a pulsating bubble surfactometer. Phosphatidylcholine comprised 41 +/- 19% of the total phospholipid in the BAL fluid of the ABCA3 group compared with 78 +/- 3% and 68 +/- 18%, p = 0.008 and 0.05, of the CON and SP-B groups, respectively. Surface tension was 31.5 +/- 9.3 mN/m and was significantly greater than CON but no different from SP-B. We conclude that mutations in ABCA3 are associated with surfactant that is deficient in phosphatidylcholine and has decreased function, suggesting that ABCA3 plays an important role in pulmonary surfactant phospholipid homeostasis.
Collapse
Affiliation(s)
- Tami H Garmany
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children's Hospital, St. Louis, Missouri, 63110, USA.
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Li J, Liepinsh E, Almlén A, Thyberg J, Curstedt T, Jörnvall H, Johansson J. Structure and influence on stability and activity of the N-terminal propeptide part of lung surfactant protein C. FEBS J 2006; 273:926-35. [PMID: 16478467 DOI: 10.1111/j.1742-4658.2006.05124.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mature lung surfactant protein C (SP-C) corresponds to residues 24-58 of the 21 kDa proSP-C. A late processing intermediate, SP-Ci, corresponding to residues 12-58 of proSP-C, lacks the surface activity of SP-C, and the SP-Ci alpha-helical structure does not unfold in contrast to the metastable nature of the SP-C helix. The NMR structure of an analogue of SP-Ci, SP-Ci(1-31), with two palmitoylCys replaced by Phe and four Val replaced by Leu, in dodecylphosphocholine micelles and in ethanol shows that its alpha-helix vs. that of SP-C is extended N-terminally. The Arg-Phe part in SP-Ci that is cleaved to generate SP-C is localized in a turn structure, which is followed by a short segment in extended conformation. Circular dichroism spectroscopy of SP-Ci(1-31) in microsomal or surfactant lipids shows a mixture of helical and extended conformation at pH 6, and a shift to more unordered structure at pH 5. Replacement of the N-terminal hexapeptide segment SPPDYS (known to constitute a signal in intracellular targeting) of SP-Ci with AAAAAA results in a peptide that is mainly unstructured, independent of pH, in microsomal and surfactant lipids. Addition of a synthetic dodecapeptide, corresponding to the propeptide part of SP-Ci, to mature SP-C results in slower aggregation kinetics and altered amyloid fibril formation, and reduces the surface activity of phospholipid-bound SP-C. These data suggest that the propeptide part of SP-Ci prevents unfolding by locking the N-terminal part of the helix, and that acidic pH results in structural disordering of the region that is proteolytically cleaved to generate SP-C.
Collapse
Affiliation(s)
- Jing Li
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
| | | | | | | | | | | | | |
Collapse
|
30
|
Noorlander CW, De Graan PNE, Middeldorp J, Van Beers JJBC, Visser GHA. Ontogeny of hippocampal corticosteroid receptors: Effects of antenatal glucocorticoids in human and mouse. J Comp Neurol 2006; 499:924-32. [PMID: 17072842 DOI: 10.1002/cne.21162] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Women at risk for preterm delivery are treated with synthetic glucocorticoids (GCs) to enhance fetal lung maturation. GCs can bind to two intracellular receptors, the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR), which function as transcription factors. Both are highly expressed in the hippocampus. Several studies have focused on adverse side effects of antenatal GC treatment. However, relatively little is known about the ontogeny of GR and MR, especially in human. Therefore, we studied the ontogeny of both receptors in the human and mouse hippocampus and investigated the effects of antenatal dexamethasone (dex) treatment, a synthetic glucocorticoid, on MR and GR mRNA levels during hippocampal development. The results demonstrate that MR mRNA was first expressed in mouse hippocampus at embryonic day (E)15.5, at the timepoint when dex was administered. In contrast, GR mRNA expression was first observed after birth at postnatal day (P)5. However, in the human hippocampus both receptors are expressed at 24 weeks of gestation, when antenatal GCs are administered in clinical practice. Quantitative in situ hybridization demonstrated that MR mRNA levels were reduced only shortly after dex treatment at E16, but were unaffected from E18 onwards. These findings indicate that a single antenatal dex administration at E15.5 transiently affects MR mRNA levels in the mouse hippocampus. No effect of antenatal dex treatment was found on the human hippocampus at the third trimester of pregnancy. These data on the prenatal ontogeny of both corticosteroid receptors in the human hippocampus is important for understanding the significance of fetal glucocorticoid or stress exposure and its potential effects on health and disease.
Collapse
Affiliation(s)
- C W Noorlander
- Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands.
| | | | | | | | | |
Collapse
|
31
|
Miller NJ, Postle AD, Orgeig S, Koster G, Daniels CB. The composition of pulmonary surfactant from diving mammals. Respir Physiol Neurobiol 2005; 152:152-68. [PMID: 16140043 DOI: 10.1016/j.resp.2005.08.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Revised: 08/03/2005] [Accepted: 08/03/2005] [Indexed: 10/25/2022]
Abstract
Maintaining a functional pulmonary surfactant system at depth is critical for diving mammals to ensure that inspiration is possible upon re-emergence. The lipid and protein composition of lavage extracts from three pinniped species (California sea lion, Northern elephant seal and Ringed seal) were compared to several terrestrial species. Lavage samples were purified using a NaBr discontinuous gradient. Concentrations of phospholipid classes and molecular species were measured using electrospray ionisation mass spectrometry, cholesterol was measured using high-performance liquid chromatography, surfactant protein A (SP-A) and SP-B were measured using enzyme-linked immunosorbent assays. There were small differences in phospholipid classes, with a lower level of anionic surfactant phospholipids, PG and PI, between diving and terrestrial mammals. There were no differences in PL saturation or SP-A levels between species. PC16:0/14:0, PC16:0/16:1, PC16:0/16:0, long chain PI species and the total concentrations of alkyl-acyl species of PC and PG as a ratio of diacyl species were increased in diving mammals, whereas concentrations of PC16:0/18:1, PG16:0/16:0 and PG16:0/18:1 were decreased. Cholesterol levels were very variable between species and SP-B was very low in diving mammals. These differences may explain the very poor surface activity of pinniped surfactant that we have previously described [Miller, N.J., Daniels, C.B., Schürch, S., Schoel, W.M., Orgeig, S., 2005. The surface activity of pulmonary surfactant from diving mammals. Respir. Physiol. Neurobiol. 150 (2006) 220-232], supporting the hypothesis that pinniped surfactant has primarily an anti-adhesive function to meet the challenges of regularly collapsing lungs.
Collapse
Affiliation(s)
- Natalie J Miller
- Environmental Biology, School of Earth and Environmental Sciences, Darling Building, University of Adelaide, North Tce, Australia
| | | | | | | | | |
Collapse
|
32
|
Ikegami M, Whitsett JA, Martis PC, Weaver TE. Reversibility of lung inflammation caused by SP-B deficiency. Am J Physiol Lung Cell Mol Physiol 2005; 289:L962-70. [PMID: 16024721 DOI: 10.1152/ajplung.00214.2005] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Whereas decreased concentrations of surfactant protein (SP)-B are associated with lung injury and respiratory distress, potential causal relationships between SP-B deficiency and lung inflammation remain unclear. A transgenic mouse in which human SP-B expression was placed under conditional control of doxycycline via the CCSP promoter was utilized to determine the role of SP-B in the initiation of pulmonary inflammation. Adult mice, made SP-B deficient by removal of doxycycline, developed severe respiratory failure within 4 days. Deficiency of SP-B was associated with increased minimal surface tension of the surfactant and perturbed lung mechanics. Four days of SP-B deficiency did not alter SP-C content or surfactant phospholipid content or composition. SP-B deficiency was associated with lung inflammation and increased soluble L-selectin, STAT-3, and phosphorylated STAT-3 in alveolar macrophages and alveolar epithelial cells. Alveolar IL-6, IL-1beta, and macrophage inflammatory protein-2 concentrations were increased after removal of doxycycline, indicating pulmonary inflammation. Restoration of SP-B expression following administration of doxycycline rapidly reversed SP-B-dependent abnormalities in lung mechanics and inflammation. SP-B deficiency is sufficient to cause lung dysfunction and inflammation in adult mice. SP-B reversed inflammation and maintained lung function in vivo, indicating its potential utility for the prevention and treatment of pulmonary injury and surfactant deficiency.
Collapse
Affiliation(s)
- Machiko Ikegami
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, USA.
| | | | | | | |
Collapse
|
33
|
Abstract
With the use of stable isotope-labeled intravenous precursors for surfactant phosphatidylcholine (PC) synthesis, it has been shown that the de novo synthesis rates in preterm infants with respiratory distress syndrome (RDS) are very low as are turnover rates. This is consistent with animal data. Surfactant therapy does not inhibit endogenous surfactant synthesis, and prenatal corticosteroids stimulate it. With the use of stable isotope-labeled PC given endotracheally, surfactant pool size was estimated. It turned out to be low in RDS, as expected. Similar studies were performed in term neonates with severe lung diseases. In general, patients with lung injury show a lower surfactant synthesis. The controversy around surfactant in congenital diaphragmatic hernia (CDH) persists: studies on CDH with and without extracorporeal membrane oxygenation yielded different results. In severe meconium aspiration syndrome surfactant synthesis was found to be decreased but surfactant pool size was maintained. It is possible and safe to study surfactant metabolism in human neonates with the use of stable isotopes. This can help in answering clinical questions and has the potential to bring new in vitro and animal findings about surfactant metabolism to the patient.
Collapse
Affiliation(s)
- L J I Zimmermann
- Division of Neonatology, University Hospital Maastricht, Maastricht, The Netherlands.
| | | | | | | | | |
Collapse
|
34
|
Hartl D, Griese M. Interstitial lung disease in children -- genetic background and associated phenotypes. Respir Res 2005; 6:32. [PMID: 15819986 PMCID: PMC1090616 DOI: 10.1186/1465-9921-6-32] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2005] [Accepted: 04/08/2005] [Indexed: 11/10/2022] Open
Abstract
Interstitial lung disease in children represents a group of rare chronic respiratory disorders. There is growing evidence that mutations in the surfactant protein C gene play a role in the pathogenesis of certain forms of pediatric interstitial lung disease. Recently, mutations in the ABCA3 transporter were found as an underlying cause of fatal respiratory failure in neonates without surfactant protein B deficiency. Especially in familiar cases or in children of consanguineous parents, genetic diagnosis provides an useful tool to identify the underlying etiology of interstitial lung disease. The aim of this review is to summarize and to describe in detail the clinical features of hereditary interstitial lung disease in children. The knowledge of gene variants and associated phenotypes is crucial to identify relevant patients in clinical practice.
Collapse
Affiliation(s)
- Dominik Hartl
- Pediatric Pneumology, Childrens' hospital of the Ludwig-Maximilians-University, Munich, Germany
| | - Matthias Griese
- Pediatric Pneumology, Childrens' hospital of the Ludwig-Maximilians-University, Munich, Germany
| |
Collapse
|
35
|
Guttentag SH, Akhtar A, Tao JQ, Atochina E, Rusiniak ME, Swank RT, Bates SR. Defective surfactant secretion in a mouse model of Hermansky-Pudlak syndrome. Am J Respir Cell Mol Biol 2005; 33:14-21. [PMID: 15790974 PMCID: PMC2715302 DOI: 10.1165/rcmb.2004-0293oc] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Hermansky-Pudlak syndrome (HPS) in humans represents a family of disorders of lysosome-related organelle biogenesis associated with severe, progressive pulmonary disease. Human case reports and a mouse model of HPS, the pale ear/pearl mouse (ep/pe), exhibit giant lamellar bodies (GLB) in type II alveolar epithelial cells. We examined surfactant proteins and phospholipid from ep/pe mice to elucidate the process of GLB formation. The 2.8-fold enrichment of tissue phospholipids in ep/pe mice resulted from accumulation from birth through adulthood. Tissue surfactant protein (SP)-B and -C were increased in adult ep/pe mice compared with wild-type mice (WT), whereas SP-A and -D were not different. Large aggregate surfactant (LA) from adult ep/pe mice had decreased phospholipid, SP-B, and SP-C, with no differences in SP-A and -D compared with WT. Although LA from ep/pe animals exhibited an increased total protein-to-total phospholipid ratio compared with WT, surface tension was not compromised. Phospholipid secretion from isolated type II cells showed that basal and stimulated secretion from ep/pe cells were approximately 50% of WT cells. Together, our data indicate that GLB formation is not associated with abnormal trafficking or recycling of surfactant material. Instead, impaired secretion is an important component of GLB formation in ep/pe mice.
Collapse
Affiliation(s)
- Susan H Guttentag
- Division of Neonatology, Department of Pediatrics, Children's Hospital of Philadelphia, 19104-4318, USA.
| | | | | | | | | | | | | |
Collapse
|
36
|
Abstract
Surfactant protein C (SP-C) is a hydrophobic 35-amino acid peptide that co-isolates with the phospholipid fraction of lung surfactant. SP-C represents a structurally and functionally challenging protein for the alveolar type 2 cell, which must synthesize, traffic, and process a 191-197-amino acid precursor protein through the regulated secretory pathway. The current understanding of SP-C biosynthesis considers the SP-C proprotein (proSP-C) as a hybrid molecule that incorporates structural and functional features of both bitopic integral membrane proteins and more classically recognized luminal propeptide hormones, which are subject to post-translational processing and regulated exocytosis. Adding to the importance of a detailed understanding of SP-C biosynthesis has been the recent association of mutations in the proSP-C sequence with chronic interstitial pneumonias in children and adults. Many of these mutations involve either missense or deletion mutations located in a region of the proSP-C molecule that has structural homology to the BRI family of proteins linked to inherited degenerative dementias. This review examines the current state of SP-C biosynthesis with a focus on recent developments related to molecular and cellular mechanisms implicated in the emerging role of SP-C mutations in the pathophysiology of diffuse parenchymal lung disease.
Collapse
Affiliation(s)
- Michael F Beers
- Pulmonary and Critical Care Division, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6061, USA.
| | | |
Collapse
|
37
|
Merrill JD, Ballard RA, Cnaan A, Hibbs AM, Godinez RI, Godinez MH, Truog WE, Ballard PL. Dysfunction of pulmonary surfactant in chronically ventilated premature infants. Pediatr Res 2004; 56:918-26. [PMID: 15496605 DOI: 10.1203/01.pdr.0000145565.45490.d9] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Infants of <30 wk gestation often require respiratory support for several weeks and may develop bronchopulmonary dysplasia (BPD), which is associated with long-term pulmonary disability or death in severe cases. To examine the status of surfactant in infants at high risk for BPD, this prospective study analyzed 247 tracheal aspirate samples from 68 infants of 23-30 wk gestation who remained intubated for 7-84 d. Seventy-five percent of the infants had one or more surfactant samples with abnormal function (minimum surface tension 5.1-21.7 mN/m by pulsating bubble surfactometer), which were temporally associated with episodes of infection (p = 0.01) and respiratory deterioration (p = 0.005). Comparing normal and abnormal surfactant samples, there were no differences in amount of surfactant phospholipid, normalized to total protein that was recovered from tracheal aspirate, or in relative content of phosphatidylcholine and phosphatidylglycerol. Contents of surfactant proteins (SP) A, B, and C, measured in the surfactant pellet by immunoassay, were reduced by 50%, 80%, and 72%, respectively, in samples with abnormal surface tension (p < or = 0.001). On multivariable analysis of all samples, SP-B content (r = -0.58, p < 0.0001) and SP-C content (r = -0.32, p < 0.001) were correlated with surfactant function. We conclude that most premature infants requiring continued respiratory support after 7 d of age experience transient episodes of dysfunctional surfactant that are associated with a deficiency of SP-B and SP-C.
Collapse
Affiliation(s)
- Jeffrey D Merrill
- Neonatology, Department of Pediatrics, University of Pennsylvania School of Medicine, USA
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Escande B, Kuhn P, Rivera S, Messer J. Les déficits secondaires en surfactant. Arch Pediatr 2004; 11:1351-9. [PMID: 15519836 DOI: 10.1016/j.arcped.2004.05.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2003] [Accepted: 05/19/2004] [Indexed: 11/21/2022]
Abstract
Preterm babies born before the 33rd week of gestation often exhibit primary surfactant deficiency responsible for the respiratory distress syndrome or hyaline membrane disease. In that situation, there is a limited and insufficient production of surfactant by type II alveolar cells of the lung due to immaturity. Secondary surfactant deficiencies occur in patients with prior normal surfactant synthesis and can be related to sepsis, hypoxia, ventilator induced lung injury or surfactant inhibition by a variety of substances reaching the alveolar spaces. They occur in full-term newborns with meconium aspiration syndrome, acute respiratory distress syndrome and congenital diaphragmatic hernia. In children and adults, acute respiratory distress syndrome and respiratory syncytial virus bronchiolitis can be responsible. In prematures they occur after the initial primary deficiency during pulmonary hemorrhage, pneumonia and bronchopulmonary dysplasia. Treatment with exogenous surfactant may be beneficial. There is a need for randomized controlled studies for evaluation of this treatment. Next generation of surfactants containing recombinant surfactant protein or synthetic peptides appear as promising agents in these situations of secondary surfactant deficiencies.
Collapse
Affiliation(s)
- B Escande
- Service de pédiatrie-II, médecine néonatale et réanimation pédiatrique, hôpital de Hautepierre, hôpitaux universitaires de Strasbourg, avenue Molière, 67098 Strasbourg cedex, France
| | | | | | | |
Collapse
|
39
|
Wilson RK, Ley TJ, Cole FS, Milbrandt JD, Clifton S, Fulton L, Fewell G, Minx P, Sun H, McLellan M, Pohl C, Mardis ER. Mutational profiling in the human genome. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2004; 68:23-9. [PMID: 15338599 DOI: 10.1101/sqb.2003.68.23] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- R K Wilson
- Washington University School of Medicine, St. Louis, Missouri 63108, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Li J, Ikegami M, Na CL, Hamvas A, Espinassous Q, Chaby R, Nogee LM, Weaver TE, Johansson J. N-terminally extended surfactant protein (SP) C isolated from SP-B-deficient children has reduced surface activity and inhibited lipopolysaccharide binding. Biochemistry 2004; 43:3891-8. [PMID: 15049696 DOI: 10.1021/bi036218q] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In both humans and mice, a deficiency of surfactant protein B (SP-B) is associated with a decreased concentration of mature SP-C and accumulation of a larger SP-C peptide, denoted SP-C(i), which is not observed under normal conditions. Isolation of hydrophobic polypeptides from the lungs of children who died with two different SP-B mutations yielded pure SP-C(i) and showed only trace amounts of mature SP-C. Determination of the SP-C(i) covalent structure revealed a 12-residue N-terminal peptide segment, followed by a 35-residue segment that is identical to mature SP-C. The SP-C(i) structure determined herein is similar to that of a proposed late intermediate in the processing of proSP-C, suggesting that SP-C(i) is the immediate precursor of SP-C. In bronchoalveolar lavage fluid from transgenic mice with a focal deficiency of SP-B, SP-C(i) was detected in the biophysically active, large aggregate fraction and was associated with membrane structures that are typical for a large aggregate surfactant. However, unlike SP-C, SP-C(i) exhibited a very poor ability to promote phospholipid adsorption, gave high surface tension during cyclic film compression, and did not bind lipopolysaccharide in vitro. SP-C(i) is thus capable of associating with surfactant lipids, but its N-terminal dodecapeptide segment must be proteolytically removed to generate a biologically functional peptide. The results of this study indicate that the early postnatal fatal respiratory distress seen in SP-B-deficient children is combined with the near absence of active variants of SP-C.
Collapse
Affiliation(s)
- Jing Li
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm, Sweden
| | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Hamvas A, Nogee LM, White FV, Schuler P, Hackett BP, Huddleston CB, Mendeloff EN, Hsu FF, Wert SE, Gonzales LW, Beers MF, Ballard PL. Progressive Lung Disease and Surfactant Dysfunction with a Deletion in Surfactant Protein C Gene. Am J Respir Cell Mol Biol 2004; 30:771-6. [PMID: 14656744 DOI: 10.1165/rcmb.2003-0323oc] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Mutations in the surfactant protein (SP)-C gene are responsible for familial and sporadic interstitial lung disease (ILD). The consequences of such mutations on pulmonary surfactant composition and function are poorly understood. To determine the effects of a mutation in the SP-C gene on surfactant, we obtained lung tissue at the time of transplantation from a 14-mo-old infant with progressive ILD. An in-frame 9-bp deletion spanning codons 91-93 in Exon 3 of the SP-C gene was present on one allele; neither parent carried this deletion. SP-C mRNA was present in normal size and amount. By immunofluorescence, proSP-C was aggregated within alveolar Type II cells in a compartment separate from SP-B. In airway surfactant, there was little or no mature SP-B or SP-C; SP-A content was increased. Minimum surface tension was increased (20 mN/m, normal < 5 mN/m). Type II cells contained normal and disorganized appearing lamellar bodies by electron microscopy. This spontaneous deletion on one allele of the SP-C gene was associated with sporadic ILD and abnormalities in surfactant composition and function. We propose that a dominant negative effect on surfactant protein metabolism and function results from aggregation of misfolded proSP-C and subsequent cell injury and inflammation.
Collapse
Affiliation(s)
- Aaron Hamvas
- Division of Newborn Medicine, Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine and St. Louis Children's Hospital, 1 Children's Place, St. Louis, MO 63110, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Abstract
The hydrophobic surfactant proteins, SP-B and SP-C, have important roles in surfactant function. The importance of these proteins in normal lung function is highlighted by the lung diseases associated with abnormalities in their expression. Mutations in the gene encoding SP-B result in severe, fatal neonatal lung disease, and mutations in the gene encoding SP-C are associated with chronic interstitial lung diseases in newborns, older children, and adults. This work reviews the current state of knowledge concerning the lung diseases associated with mutations in the SP-B and SP-C genes, and the potential roles of abnormal SP-B and SP-C expression and genetic variation in these genes in other lung diseases.
Collapse
Affiliation(s)
- Lawrence M Nogee
- Division of Neonatology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-3200, USA.
| |
Collapse
|
43
|
Affiliation(s)
- Maureen R Horton
- Johns Hopkins University School of Medicine, Division of Pulmonary and Critical Care Medicine, Baltimore, Maryland 21205, USA.
| |
Collapse
|
44
|
Abstract
Surfactant Protein B (SP-B) deficiency has been recently identified as an uncommon, autosomal recessive lung disorder in term infants. This inability to produce SP-B leads to progressive, lethal, hypoxemic respiratory failure in the first year of life. A frameshift mutation (121 ins 2) is the predominant but not exclusive cause. The clue to diagnosis is to have a high suspicion of SP-B deficiency in any term infant with severe respiratory distress without any apparent cause. SP-B deficiency can be diagnosed prenatally or postnatally. The only current treatment options available include lung transplantation or compassionate care. Current developments in gene therapy offer hope for future treatment.
Collapse
Affiliation(s)
- Mary Ann Wilder
- Neonatal Intensive Care Unit, Pediatrix Medical Group, Valley Hospital Medical Center, Las Vegas, NV 89106, USA.
| |
Collapse
|
45
|
Abstract
Pulmonary alveolar proteinosis (PAP) is characterized by the accumulation of surfactant phospholipids and proteins within the lung alveoli. Important advances have been made over the past 8 years in our understanding of this disease, offering new directions for research and patient care. First, genetically altered mice that are homozygous for a disrupted granulocyte-macrophage colony-stimulating factor (GM-CSF) gene developed a lung lesion with histologic resemblance to PAP. The surfactant is thought to be catabolized or cleared mostly by alveolar macrophages, this process being dependent on GM-CSF. Second, a neutralizing autoantibody against GM-CSF was found in serum and bronchoalveolar lavage fluid of patients with idiopathic PAP but not in healthy controls, thereby raising the suspicion that human PAP may be an autoimmune disease. The relationship between the antibody and disease pathogenesis remains unclear but data suggest that the GM-CSF antibody may have a potential role as a diagnostic test. No specific therapy exists for PAP. Sequential whole lung lavage is the standard of care. Exogenous therapy with GM-CSF may improve the lung disease in some patients with PAP but this therapy is still experimental. Interventions directed at treating a relative GM-CSF deficiency by administration of GM-CSF or lowering the antibody level (i.e. by plasmapheresis or immunosuppression) may hold promise as future therapy for this rare disease.
Collapse
Affiliation(s)
- Saiprakash B Venkateshiah
- Department of Pulmonary and Critical Care Medicine, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | | | | |
Collapse
|
46
|
Brasch F, Ochs M, Kahne T, Guttentag S, Schauer-Vukasinovic V, Derrick M, Johnen G, Kapp N, Muller KM, Richter J, Giller T, Hawgood S, Buhling F. Involvement of napsin A in the C- and N-terminal processing of surfactant protein B in type-II pneumocytes of the human lung. J Biol Chem 2003; 278:49006-14. [PMID: 13129928 DOI: 10.1074/jbc.m306844200] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Surfactant protein B (SP-B) is a critical component of pulmonary surfactant, and a deficiency of active SP-B results in fatal respiratory failure. SP-B is synthesized by type-II pneumocytes as a 42-kDa propeptide (proSP-B), which is posttranslationally processed to an 8-kDa surface-active protein. Napsin A is an aspartic protease expressed in type-II pneumocytes. To characterize the role of napsin A in the processing of proSP-B, we colocalized napsin A and precursors of SP-B as well as SP-B in the Golgi complex, multivesicular, composite, and lamellar bodies of type-II pneumocytes in human lungs using immunogold labeling. Furthermore, we measured aspartic protease activity in isolated lamellar bodies as well as isolated human type-II pneumocytes and studied the cleavage of proSP-B by napsin A and isolated lamellar bodies in vitro. Both, napsin A and isolated lamellar bodies cleaved proSP-B and generated three identical processing products. Processing of proSP-B by isolated lamellar bodies was completely inhibited by an aspartic protease inhibitor. Sequence analysis of proSP-B processing products revealed several cleavage sites in the N- and C-terminal propeptides as well as one in the mature peptide. Two of the four processing products generated in vitro were also detected in type-II pneumocytes. In conclusion, our results show that napsin A is involved in the N- and C-terminal processing of proSP-B in type-II pneumocytes.
Collapse
Affiliation(s)
- Frank Brasch
- Department of Anatomy, University of Göttingen, Kreuzbergring 36, D-37075 Göttingen, Germany.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Melton KR, Nesslein LL, Ikegami M, Tichelaar JW, Clark JC, Whitsett JA, Weaver TE. SP-B deficiency causes respiratory failure in adult mice. Am J Physiol Lung Cell Mol Physiol 2003; 285:L543-9. [PMID: 12639841 DOI: 10.1152/ajplung.00011.2003] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Targeted deletion of the surfactant protein (SP)-B locus in mice causes lethal neonatal respiratory distress. To assess the importance of SP-B for postnatal lung function, compound transgenic mice were generated in which the mouse SP-B cDNA was conditionally expressed under control of exogenous doxycycline in SP-B-/- mice. Doxycycline-regulated expression of SP-B fully corrected lung function in compound SP-B-/- mice and protected mice from respiratory failure at birth. Withdrawal of doxycycline from adult compound SP-B-/- mice resulted in decreased alveolar content of SP-B, causing respiratory failure when SP-B concentration was reduced to <25% of normal levels. Decreased SP-B was associated with low alveolar content of phosphatidylglycerol, accumulation of misprocessed SP-C proprotein in the air spaces, increased protein content in bronchoalveolar lavage fluid, and altered surfactant activity in vitro. Consistent with surfactant dysfunction, hysteresis, maximal tidal volumes, and end expiratory volumes were decreased. Reduction of alveolar SP-B content causes surfactant dysfunction and respiratory failure, indicating that SP-B is required for postnatal lung function.
Collapse
Affiliation(s)
- Kristin R Melton
- Cincinnati Children's Hospital Medical Center, Division of Pulmonary Biology, 3333 Burnet Ave., Cincinnati, OH 45229-3039, USA
| | | | | | | | | | | | | |
Collapse
|
48
|
Foster CD, Zhang PX, Gonzales LW, Guttentag SH. In vitro surfactant protein B deficiency inhibits lamellar body formation. Am J Respir Cell Mol Biol 2003; 29:259-66. [PMID: 12649122 DOI: 10.1165/rcmb.2002-0149oc] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Surfactant protein (SP) B is essential for normal pulmonary surfactant activity and lamellar body genesis in type 2 cells. However, the role of SP-B in lamellar body genesis is poorly understood. We developed an adenovirus vector expressing antisense SP-B as an alternative in vitro model of SP-B deficiency to begin to explore the role of SP-B in lamellar body genesis. RT-PCR analysis revealed that antisense SP-B expression interfered with translation of endogenous SP-B mRNA. Antisense SP-B expression resulted in reliable in vitro reproduction of many features of SP-B deficiency, including absent mature SP-B and decreased lamellar bodies and SP-C. Light and electron microscopy demonstrated significant reductions in lamellar body number. Western blotting revealed a significant reduction in mature 8-kD SP-B protein and decreased mature SP-C. Our data indicate that antisense SP-B can be effectively used to replicate the SP-B-deficient type 2 cell phenotype in vitro, and provides an attractive alternative to transgenic models for the further study of the role of SP-B in lamellar body genesis.
Collapse
Affiliation(s)
- Cherie D Foster
- Department of Pediatrics, University of Pennsylvania School of Medicine, Children's Hospital of Philadelphia, 3516 Civic Center Blvd., Philadelphia, PA 19104-4318, USA
| | | | | | | |
Collapse
|
49
|
Abstract
Surfactant therapy has revolutionized neonatal care and is used routinely for preterm infants with respiratory distress syndrome. Recent investigation has further elucidated the function of surfactant-associated proteins and their contribution toward surfactant and lung immune defense functions. As the field of neonatology moves away from intubation and mechanical ventilation of preterm infants at birth toward more aggressive use of nasal continuous positive airway pressure, the optimal timing of exogenous surfactant therapy remains unclear. Evidence suggests that preterm neonates with bronchopulmonary dysplasia and prolonged mechanical ventilation also experience surfactant dysfunction; however, exogenous surfactant therapy beyond the first week of life has not been well studied. Surfactant replacement therapy has been studied for use in other respiratory disorders, including meconium aspiration syndrome and pneumonia. Commercial surfactant preparations currently available are not optimal, given the variability of surfactant protein content and their susceptibility to inhibition. Further progress in the treatment of neonatal respiratory disorders may include the development of "designer" surfactant preparations.
Collapse
Affiliation(s)
- Jeffrey D Merrill
- Division of Neonatology, University of Pennsylvania School of Medicine, Hospital of the University of Pennsylvania, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | | |
Collapse
|
50
|
Guttentag S, Robinson L, Zhang P, Brasch F, Bühling F, Beers M. Cysteine protease activity is required for surfactant protein B processing and lamellar body genesis. Am J Respir Cell Mol Biol 2003; 28:69-79. [PMID: 12495934 DOI: 10.1165/rcmb.2002-0111oc] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Surfactant protein (SP)-B is essential for lamellar body genesis and for the final steps in proSP-C post-translational processing. The mature SP-B protein is derived from multistep processing of the primary translation product proSP-B; however, the enzymes required for these events are currently unknown. Recent ultrastructural colocalization studies have suggested that the cysteine protease Cathepsin H may be involved in proSP-B processing. Using models of isolated human type 2 cells in culture, we describe the effects of cysteine protease inhibition by E-64 on SP-B processing and type 2 cell differentiation. Pulse-chase labeling and Western immunoblotting studies showed that the final step of SP-B processing, specifically cleavage of SP-B(9) to SP-B(8), was significantly inhibited by E-64, resulting in delayed accumulation of SP-B(8) without adverse effects on SP-A or glyceraldehyde phosphate dehydrogenase expression. E-64 treatment during type 2 cell differentiation mimicked features of inherited SP-B deficiency in humans and mice, specifically disrupted lamellar body genesis, and aberrant processing of proSP-C. Reverse transcriptase-polymerase chain reaction and Western immunoblotting studies showed that Cathepsin H is induced during in vitro differentiation of type 2 cells and localizes with SP-B in multivesicular bodies, composite bodies, and lamellar bodies by immunoelectron microscopy. Furthermore, Cathepsin H activity was specifically inhibited in a dose-dependent fashion by E-64. Our data show that a cysteine protease is involved in SP-B processing, lamellar body genesis, and SP-C processing, and suggest that Cathepsin H is the most likely candidate protease.
Collapse
Affiliation(s)
- Susan Guttentag
- Division of Neonatology, Department of Pediatrics, University of Pennsylvania School of Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104-4318, USA.
| | | | | | | | | | | |
Collapse
|