1
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Umstead TM, Hewage EK, Mathewson M, Beaudoin S, Chroneos ZC, Wang M, Halstead ES. Lower respiratory tract delivery, airway clearance, and preclinical efficacy of inhaled GM-CSF in a postinfluenza pneumococcal pneumonia model. Am J Physiol Lung Cell Mol Physiol 2020; 318:L571-L579. [PMID: 31994895 DOI: 10.1152/ajplung.00296.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Inhaled granulocyte/macrophage colony-stimulating factor (GM-CSF) shows promise as a therapeutic to treat viral and bacterial pneumonia, but no mouse model of inhaled GM-CSF has been described. We sought to 1) develop a mouse model of aerosolized recombinant mouse GM-CSF administration and 2) investigate the protection conferred by inhaled GM-CSF during influenza A virus (IAV) infection against secondary bacterial infection with pneumococcus. To assess lower respiratory tract delivery of aerosolized therapeutics, mice were exposed to aerosolized fluorescein (FITC)-labeled dextran noninvasively via an aerosolization tower or invasively using a rodent ventilator. The efficiency of delivery to the lower respiratory tracts of mice was 0.01% noninvasively compared with 0.3% invasively. The airway pharmacokinetics of inhaled GM-CSF fit a two-compartment model with a terminal phase half-life of 1.3 h. To test if lower respiratory tract levels were sufficient for biological effect, mice were infected intranasally with IAV, treated with aerosolized recombinant mouse GM-CSF, and then secondarily infected with Streptococcus pneumoniae. Inhaled GM-CSF conferred a significant survival benefit to mice against secondary challenge with S. pneumoniae (P < 0.05). Inhaled GM-CSF did not reduce airway or lung parenchymal bacterial growth but significantly reduced the incidence of S. pneumoniae bacteremia (P < 0.01). However, GM-CSF overexpression during influenza virus infection did not affect lung epithelial permeability to FITC-dextran ingress into the bloodstream. Therefore, the mechanism of protection conferred by inhaled GM-CSF appears to be locally mediated improved lung antibacterial resistance to systemic bacteremia during IAV infection.
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Affiliation(s)
- Todd M Umstead
- Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, Pennsylvania.,Pulmonary Immunology and Physiology Laboratory, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Eranda Kurundu Hewage
- Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, Pennsylvania.,Pulmonary Immunology and Physiology Laboratory, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Margaret Mathewson
- Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, Pennsylvania.,Pulmonary Immunology and Physiology Laboratory, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Sarah Beaudoin
- Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, Pennsylvania.,Pulmonary Immunology and Physiology Laboratory, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Zissis C Chroneos
- Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, Pennsylvania.,Pulmonary Immunology and Physiology Laboratory, Pennsylvania State University College of Medicine, Hershey, Pennsylvania.,Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Ming Wang
- Department of Public Health Sciences, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - E Scott Halstead
- Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, Pennsylvania.,Pulmonary Immunology and Physiology Laboratory, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
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2
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Glisinski KM, Schlobohm AJ, Paramore SV, Birukova A, Moseley MA, Foster MW, Barkauskas CE. Interleukin-13 disrupts type 2 pneumocyte stem cell activity. JCI Insight 2020; 5:131232. [PMID: 31941839 DOI: 10.1172/jci.insight.131232] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 12/04/2019] [Indexed: 12/28/2022] Open
Abstract
The T helper 2 (Th2) inflammatory cytokine interleukin-13 (IL-13) has been associated with both obstructive and fibrotic lung diseases; however, its specific effect on the epithelial stem cells in the gas exchange compartment of the lung (alveolar space) has not been explored. Here, we used in vivo lung models of homeostasis and repair, ex vivo organoid platforms, and potentially novel quantitative proteomic techniques to show that IL-13 disrupts the self-renewal and differentiation of both murine and human type 2 alveolar epithelial cells (AEC2s). Significantly, we find that IL-13 promotes ectopic expression of markers typically associated with bronchiolar airway cells and commonly seen in the alveolar region of lung tissue from patients with idiopathic pulmonary fibrosis. Furthermore, we identify a number of proteins that are differentially secreted by AEC2s in response to IL-13 and may provide biomarkers to identify subsets of patients with pulmonary disease driven by "Th2-high" biology.
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Affiliation(s)
- Kristen M Glisinski
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, and
| | - Adam J Schlobohm
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, and
| | - Sarah V Paramore
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, and
| | - Anastasiya Birukova
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, and
| | - M Arthur Moseley
- Duke Proteomics and Metabolomics Shared Resource, Duke University Medical Center, Durham, North Carolina, USA
| | - Matthew W Foster
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, and.,Duke Proteomics and Metabolomics Shared Resource, Duke University Medical Center, Durham, North Carolina, USA
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3
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Epaud R, Delestrain C, Weaver TE, Akinbi HT. Bacterial killing is enhanced by exogenous administration of lysozyme in the lungs. Respir Med Res 2019; 76:22-27. [PMID: 31505323 DOI: 10.1016/j.resmer.2019.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 07/14/2019] [Accepted: 07/15/2019] [Indexed: 12/01/2022]
Abstract
OBJECTIVE Lysozyme, a 14-kDa protein, is one of the most abundant antimicrobials in the lungs. Its concentration in airway surface sufficient to kill several bacterial pathogens in vitro. The purpose of this study was to determine if administration of exogenous lysozyme would further enhance bacterial killing in vivo. METHODS To assess the effect of acute lung infection on endogenous lysozyme protein levels, mice were infected by intratracheal instillation of Pseudomonas aeruginosa and bronchoalveolar (BAL) fluid assessed for lysozyme concentration and for muramidase activity. In order to inform in vivo testing, species-specific bacterial killing efficacy was determined by incubating mucoid P. aeruginosa with 2×105 units of chicken lysozyme, human lysozyme or with vehicle at 37°C for 2hours. Subsequently, mice challenged with intratracheally-administered mucoid P. aeruginosa, were reintubated and injected with 2×105 Units of native human lysozyme, recombinant human lysozyme or with vehicle. Lung bacterial burden was enumerated subsequently. RESULTS The concentration of lysozyme protein in BAL fluid from mice challenged with mucoid clinical isolate of P. aeruginosa was increased 4-fold at 6hours post-infection. Quantitative culture showed that the number of recoverable bacteria was significantly decreased by both chicken and human lysozyme compared to vehicle but human lysozyme was significantly more effective than chicken egg lysozyme. In vivo, 24hours post-infection quantitative culture of lung homogenates showed that the number of viable bacteria recovered from mice treated with either native or recombinant lysozyme was decreased with 0.76±0.25×104 and 0.84±0.16×104, respectively, vs. 7.0±2.52×104 CFU/g protein in mice treated with HBSS, both P<0.05. CONCLUSIONS These results indicate that endogenous lysozyme is increased during acute lung infection and that early administration of exogenous lysozyme further enhances bacterial killing in vivo.
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Affiliation(s)
- R Epaud
- Pediatric Department, Centre Intercommunal de Créteil, Créteil, France; Inserm, Unité 955, Equipe 5, Créteil, France; Centre des Maladies Respiratoires Rare, Respirare®, Paris, France; Université Paris-Est, Faculté de Médecine, Créteil, France; Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, and the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - C Delestrain
- Pediatric Department, Centre Intercommunal de Créteil, Créteil, France; Inserm, Unité 955, Equipe 5, Créteil, France; Centre des Maladies Respiratoires Rare, Respirare®, Paris, France; Université Paris-Est, Faculté de Médecine, Créteil, France
| | - T E Weaver
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, and the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - H T Akinbi
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, and the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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4
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Maguire PB, Donlon T, Parsons M, Wynne K, Dillon E, Ní Áinle F, Szklanna PB. Proteomic Analysis Reveals a Strong Association of β-Catenin With Cadherin Adherens Junctions in Resting Human Platelets. Proteomics 2019; 18:e1700419. [PMID: 29510447 DOI: 10.1002/pmic.201700419] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 02/19/2018] [Indexed: 12/16/2022]
Abstract
It was previously demonstrated that the WNT/β-catenin pathway is present and active in platelets and established that the canonical WNT ligand, WNT-3a, suppresses platelet adhesion and activation. In nucleated cells, β-catenin, the key downstream effector of this pathway, is a dual function protein, regulating the coordination of gene transcription and cell-cell adhesion. The specific role of β-catenin in the anucleate platelet however remains elusive. Here, a label-free quantitative proteomic analysis of β-catenin immunoprecipitates from human platelets is performed and nine co-immunoprecipitating proteins are identified. Three of the co-immunoprecipitating proteins (α-catenin-1, cadherin-6, and β-catenin-interacting protein 1) are common to both resting and activated conditions. Bioinformatics analysis of proteomics data reveal a strong association of the dataset with both cadherin adherens junctions and regulators of WNT signaling. It is then verified that platelet β-catenin and cadherin-6 interact and that this interaction is regulated by the activation state of the platelet. Taken together, this proteomics study suggests a novel role for β-catenin in human platelets where it interacts with platelet cadherins and associated junctional proteins.
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Affiliation(s)
- Patricia B Maguire
- UCD Conway Institute, Conway SPHERE Research Group, School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland.,UCD Institute for Discovery, O'Brien Centre for Science, University College Dublin, Dublin, Ireland
| | - Tim Donlon
- UCD Conway Institute, Conway SPHERE Research Group, School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Martin Parsons
- UCD Conway Institute, Conway SPHERE Research Group, School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Kieran Wynne
- UCD Conway Institute Proteomics Core, University College Dublin, Dublin, Ireland
| | - Eugene Dillon
- UCD Conway Institute Proteomics Core, University College Dublin, Dublin, Ireland
| | - Fionnuala Ní Áinle
- UCD Conway Institute, School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland
| | - Paulina B Szklanna
- UCD Conway Institute, Conway SPHERE Research Group, School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
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5
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Novel peptide motifs from lysozyme suppress pro-inflammatory cytokines in macrophages by antagonizing toll-like receptor and LPS-scavenging action. Eur J Pharm Sci 2017; 107:240-248. [PMID: 28711715 DOI: 10.1016/j.ejps.2017.07.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 06/29/2017] [Accepted: 07/06/2017] [Indexed: 02/07/2023]
Abstract
Lysozyme is commonly found in spots where bacterial infections are most likely to enter the body. Earlier we found that lysozyme possesses five antimicrobial peptide motifs in its N-terminal region which can be generated by newborn pepsin. In this study, we explore the role of these peptides in the anti-inflammatory activity of lysozyme. The five peptides, helix1 (H1), helix2 (H2), H1 and H2 connected with a loop (HLH), H2 extended with either 2 β-strands (H2-S12) or 3 β-strands (H2-S13), were synthesized and examined for anti-inflammatory action. The five peptides dose-dependently decreased, to different degrees, expression of pro-inflammatory cytokines, TNF-α, IL-6 and IL-1β, in lipopolysaccharide (LPS)- or interferon-gamma (INF-γ)-stimulated mouse macrophage cells (RAW264.7). The HLH peptide and its individual helices (H1 and H2) were markedly the most potent anti-inflammatory. When macrophage cells were stimulated with live bacteria (E. coli), H1 peptide was the most powerful suppressor of TNF-α and IL-6 expression, providing evidence that the peptide is able to antagonize the pathogen-induced inflammatory response. Receptor binding assay and docking simulation provided evidence that H1 peptide bind specifically to the pocket for endotoxin binding of the toll-like receptor 4 (TLR-4) of macrophage. The results demonstrate, for the first time, the molecular basis of anti-inflammatory action of lysozyme that N-terminal helical peptides are the main contributors. This exciting finding offers new classes of therapeutic peptides with potential in the treatment of infection-induced inflammatory diseases.
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6
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Ibrahim HR, Imazato K, Ono H. Human lysozyme possesses novel antimicrobial peptides within its N-terminal domain that target bacterial respiration. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:10336-10345. [PMID: 21851100 DOI: 10.1021/jf2020396] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Human milk lysozyme is thought to be a key defense factor in protecting the gastrointestinal tract of newborns against bacterial infection. Recently, evidence was found that pepsin, under conditions relevant to the newborn stomach, cleaves chicken lysozyme (cLZ) at specific loops to generate five antimicrobial peptide motifs. This study explores the antimicrobial role of the corresponding peptides of human lysozyme (hLZ), the actual protein in breast milk. Five peptide motifs of hLZ, one helix-loop-helix (HLH), its two helices (H1 and H2), and two helix-sheet motifs, H2-β-strands 1-2 (H2-S12) or H2-β-strands 1-3 (H2-S13), were synthesized and examined for antimicrobial action. The five peptides of hLZ exhibit microbicidal activity to various degrees against several bacterial strains. The HLH peptide and its N-terminal helix (H1) were significantly the most potent bactericidal to Gram-positive and Gram-negative bacteria and the fungus Candida albicans . Outer and inner membrane permeabilization studies, as well as measurements of transmembrane electrochemical potentials, provided evidence that HLH peptide and its N-terminal helix (H1) kill bacteria by crossing the outer membrane of Gram-negative bacteria via self-promoted uptake and are able to dissipate the membrane potential-dependent respiration of Gram-positive bacteria. This finding is the first to describe that hLZ possesses multiple antimicrobial peptide motifs within its N-terminal domain, providing insight into new classes of antibiotic peptides with potential use in the treatment of infectious diseases.
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Affiliation(s)
- Hisham R Ibrahim
- Department of Biochemistry and Biotechnology, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan.
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7
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Abstract
IMPORTANCE OF THE FIELD Antibiotic resistance is a serious problem that continues to challenge the healthcare sectors and has become increasingly alarming in the past few years. To face this emerging global crisis, there is a need to find a new class of antibiotics that act on new microbial targets and/or harness existing antibiotics by developing new drug-targeting strategies. AREAS COVERED IN THIS REVIEW This review: explores an innovative drug-delivery strategy of using hen egg lysozyme as a carrier to enable water solubilization and to allow specific targeting to the microbial cells of a water-insoluble antimicrobial agent with a powerful killing action; addresses potentials for lysozyme in antibiotics drug targeting; and provides insight for the future direction of this highly prospective technology. WHAT THE READER WILL GAIN The unique features and advantages of lysozyme-based drug delivery system are highlighted. The efficiency of lysozyme in solubilization and delivery of lipophilic antibiotics, to reformulate drugs that may fail clinical trials owing to low solubility, is emphasized. TAKE HOME MESSAGE Fewer pharmaceutical companies are inventing new antibiotics because of long development times and high failure rates. Combining lysozyme with a powerful old antibiotic may open doors to revolutionizing medicine, particularly in the treatment of deadly infections.
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Affiliation(s)
- Hisham R Ibrahim
- Department of Biochemistry and Biotechnology, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan.
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8
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Feng NH, Lin HI, Wang JS, Chou ST, Ma HK, Rooney SA, Lu JF. Differential expression of a V-type ATPase C subunit gene, Atp6v1c2, during culture of rat lung type II pneumocytes. J Biomed Sci 2005; 12:899-911. [PMID: 16283434 DOI: 10.1007/s11373-005-9020-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Accepted: 08/03/2005] [Indexed: 01/05/2023] Open
Abstract
The lung alveolar epithelium consists of type I and type II pneumocytes. In vivo, the type II cell is the progenitor cell from which the type I cell originates. When freshly-isolated type II cells are cultured under conventional conditions they rapidly lose their phenotypic properties and attain characteristics of type I cells. Taking advantage of this transdifferentiation, we sought to identify genes that are differentially expressed during culture of rat type II cells. Using suppression subtractive hybridization (SSH), a vacuolar-type H+-ATPase (V-ATPase) C2 subunit gene (Atp6v1c2) was found to be enriched in freshly isolated rat type II cells compared to those cultured for 4 days. Northern blotting and reverse-transcription polymerase chain reaction (RT-PCR) confirmed the differential expression of Atp6v1c2 during in vitro culture of isolated type II cells. Expression ofAtp6v1c2 was significantly reduced early during in vitro culture: almost 90% reduction was observed after 24 h of incubation as determined by real-time PCR. In situ hybridization showed that Atp6v1c2 is expressed in both bronchiolar and alveolar lung epithelial cells, an expression pattern similar to that of surfactant protein B (SP-B). Multi-tissue Northern blotting revealed a unique tissue distribution with Atp6v1c2 expression limited to lung, kidney and testis. The presence and expression of Atp6v1c2 gene transcript isoforms, resulting from alternative splicing, were also investigated. Elucidation of differential expression of Atp6v1c2 in type II cells and further studies of its regulation may provide information useful in understanding the molecular mechanism underlying phenotypic and functional changes during transdifferentiation of alveolar epithelial cells.
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MESH Headings
- Alternative Splicing
- Amino Acid Sequence
- Animals
- Blotting, Northern
- Blotting, Western
- Cell Culture Techniques
- Cell Differentiation
- Cells, Cultured
- Cloning, Molecular
- DNA, Complementary/metabolism
- Expressed Sequence Tags
- Gene Expression Regulation, Enzymologic
- In Situ Hybridization
- Lung/cytology
- Lung/metabolism
- Macrophages/metabolism
- Molecular Sequence Data
- Nucleic Acid Hybridization
- Oligonucleotides/chemistry
- Phenotype
- Protein Isoforms
- Pulmonary Alveoli/metabolism
- Pulmonary Surfactant-Associated Protein B/metabolism
- RNA/metabolism
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Time Factors
- Tissue Distribution
- Vacuolar Proton-Translocating ATPases/biosynthesis
- Vacuolar Proton-Translocating ATPases/genetics
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Affiliation(s)
- Nan-Hsiung Feng
- Department of Internal Medicine, Kaohsiung Military General Hospital, Kaohsiung, Taiwan, ROC
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9
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Okubo C, Morishita Y, Minami Y, Ishiyama T, Kano J, Iijima T, Noguchi M. Phenotypic characteristics of mouse lung adenoma induced by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone. Mol Carcinog 2005; 42:121-6. [PMID: 15584020 DOI: 10.1002/mc.20070] [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: 11/09/2022]
Abstract
The expression profile of adenoma induced by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in A/J mice was compared with that of normal lung tissue by suppression subtractive hybridization (SSH). The mRNAs of surfactant-associated protein A (SP-A) and lysozyme showed characteristically higher transcription in the adenoma tissue than in normal lung. High expression of both SP-A and lysozyme in tumor cells was confirmed by in situ hybridization (ISH). In normal lung, alveolar type II pneumocytes were positive for both SP-A and lysozyme, indicating that tumor cells retained the phenotypic characteristics of the murine alveolar type II pneumocytes. Previous studies of human adenocarcinomas have shown that the two proteins are expressed reciprocally; SP-A and lysozyme are differential markers of atypical adenomatous hyperplasia (AAH) and non-goblet cell type adenocarcinoma, and of goblet cell type adenocarcinoma, respectively. Thus, the present results indicate that the phenotype of NNK-induced A/J mouse adenoma differs from that of AAH, which is thought to be a preinvasive lesion of human adenocarcinoma.
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Affiliation(s)
- Chigusa Okubo
- Department of Pathology, Institute of Basic Medical Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba-shi, Ibaraki 3058575, Japan
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10
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Cantor JO, Shteyngart B, Cerreta JM, Turino GM. The effect of lysozyme on elastase-mediated injury. Exp Biol Med (Maywood) 2002; 227:108-13. [PMID: 11815674 DOI: 10.1177/153537020222700205] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Previous studies by this laboratory demonstrated that lysozyme is increased in human pulmonary emphysema, and that it preferentially binds to elastic fibers, which undergo degradation in this disease. In the current investigation, the relationship between lysozyme and elastic fiber injury was further examined, both in vitro and in vivo. The effect of exogenously administered egg-white lysozyme on pancreatic elastase-induced injury was determined using a biosynthetically radiolabeled extracellular matrix preparation mainly composed of elastic fibers. Although matrix treated with lysozyme showed attachment of the protein to elastic fibers, there was no significant increase in elastolysis compared with untreated controls following exposure to either 1 microg/ml or 100 ng/ml of pancreatic elastase. However, lysozyme did impair the ability of hyaluronan (HA) to prevent elastase injury to elastic fibers. Matrix samples sequentially treated with lysozyme and HA, then incubated with 1 microg/ml or 100 ng/ml of pancreatic elastase, showed significantly increased elastolysis compared with those treated with HA alone. Since HA is closely associated with elastic fibers in vivo, the ability of lysozyme to enhance elastolysis was further tested in an animal model of emphysema induced by intratracheal administration of porcine pancreatic elastase. Animals exposed to aerosolized lysozyme prior to elastase administration showed significantly increased airspace enlargement. The mean linear intercept of the lysozyme-treated animals was 123 microm compared with 75 microm for controls receiving aerosolized water (P < 0.0001). These findings suggest that lysozyme may not be an innocuous component of the inflammatory response associated with pulmonary emphysema, but may actually play a role in the pathogenesis of the disease.
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Affiliation(s)
- Jerome O Cantor
- St. Luke's-Roosevelt Hospital Center, New York, New York, USA.
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11
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Fehrenbach H. Alveolar epithelial type II cell: defender of the alveolus revisited. Respir Res 2001; 2:33-46. [PMID: 11686863 PMCID: PMC59567 DOI: 10.1186/rr36] [Citation(s) in RCA: 527] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2000] [Revised: 12/05/2000] [Accepted: 12/06/2000] [Indexed: 01/13/2023] Open
Abstract
In 1977, Mason and Williams developed the concept of the alveolar epithelial type II (AE2) cell as a defender of the alveolus. It is well known that AE2 cells synthesise, secrete, and recycle all components of the surfactant that regulates alveolar surface tension in mammalian lungs. AE2 cells influence extracellular surfactant transformation by regulating, for example, pH and [Ca2+] of the hypophase. AE2 cells play various roles in alveolar fluid balance, coagulation/fibrinolysis, and host defence. AE2 cells proliferate, differentiate into AE1 cells, and remove apoptotic AE2 cells by phagocytosis, thus contributing to epithelial repair. AE2 cells may act as immunoregulatory cells. AE2 cells interact with resident and mobile cells, either directly by membrane contact or indirectly via cytokines/growth factors and their receptors, thus representing an integrative unit within the alveolus. Although most data support the concept, the controversy about the character of hyperplastic AE2 cells, reported to synthesise profibrotic factors, proscribes drawing a definite conclusion today.
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Affiliation(s)
- H Fehrenbach
- Institute of Pathology, University Clinics Carl Gustav Carus, Technical University of Dresden, Germany.
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12
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Jia HP, Mills JN, Barahmand-Pour F, Nishimura D, Mallampali RK, Wang G, Wiles K, Tack BF, Bevins CL, McCray PB. Molecular cloning and characterization of rat genes encoding homologues of human beta-defensins. Infect Immun 1999; 67:4827-33. [PMID: 10456937 PMCID: PMC96815 DOI: 10.1128/iai.67.9.4827-4833.1999] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
beta-Defensins are cationic peptides with broad-spectrum antimicrobial activity that may play a role in mucosal defenses of several organs. They have been isolated in several species, and in humans, two beta-defensins have been identified. Here, we report the identification of two genes encoding beta-defensin homologues in the rat. Partial cDNAs were found by searching the expressed-sequence-tag database, and primers were designed to generate full-length mRNA coding sequences. One gene was highly similar to the human beta-defensin-1 (HBD-1) gene and mouse beta-defensin-1 gene at both the nucleic acid and amino acid levels and was termed rat beta-defensin-1 (RBD-1). The other gene, named RBD-2, was homologous to the HBD-2 and bovine tracheal antimicrobial peptide (TAP) genes. The predicted prepropeptides were strongly cationic, were 69 and 63 residues in length for RBD-1 and RBD-2, respectively, and contained the six-cysteine motif characteristic of beta-defensins. The beta-defensin genes mapped closely on rat chromosome 16 and were closely linked to the alpha-defensins genes, suggesting that they are part of a gene cluster, similar to the organization reported for humans. Northern blot analysis showed that both RBD-1 and RBD-2 mRNA transcripts were approximately 0.5 kb in length; RBD-1 mRNA was abundantly transcribed in the rat kidney, while RBD-2 was prevalent in the lung. Reverse transcription-PCR indicated that RBD-1 and RBD-2 mRNAs were distributed in a variety of other tissues. In the lung, RBD-1 mRNA expression localized to the tracheal epithelium while RBD-2 was expressed in alveolar type II cells. In conclusion, we characterized two novel beta-defensin homologues in the rat. The rat may be a useful model to investigate the function and contribution of beta-defensins to host defense in the lung, kidney, and other tissues.
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Affiliation(s)
- H P Jia
- Department of Pediatrics, University of Iowa College of Medicine, Iowa City, Iowa, USA
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13
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McCray PB, Zabner J, Jia HP, Welsh MJ, Thorne PS. Efficient killing of inhaled bacteria in DeltaF508 mice: role of airway surface liquid composition. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:L183-90. [PMID: 10409246 DOI: 10.1152/ajplung.1999.277.1.l183] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cystic fibrosis mice have been generated by gene targeting but show little lung disease without repeated exposure to bacteria. We asked if murine mucosal defenses and airway surface liquid (ASL) Cl(-) were altered by the DeltaF508 cystic fibrosis transmembrane conductance regulator mutation. Naive DeltaF508 -/- and +/- mice showed no pulmonary inflammation and after inhaled Pseudomonas aeruginosa had similar inflammatory responses and bacterial clearance rates. We therefore investigated components of the innate immune system. Bronchoalveolar lavage fluid from mice killed Escherichia coli, and the microbicidal activity was inhibited by NaCl. Because beta-defensins are salt-sensitive epithelial products, we looked for pulmonary beta-defensin expression. A mouse homolog of human beta-defensin-1 (termed "MBD-1") was identified; the mRNA was expressed in the lung. Using a radiotracer technique, ASL volume and Cl(-) concentration ([Cl(-)]) were measured in cultured tracheal epithelia from normal and DeltaF508 -/- mice. The estimated ASL volume was similar for both groups. There were no differences in ASL [Cl(-)] in DeltaF508 -/- and normal mice (13.8 +/- 2.6 vs. 17.8 +/- 5.6 meq/l). Because ASL [Cl(-)] is low in normal and mutant mice, salt-sensitive antimicrobial factors, including MBD-1, may be normally active.
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Affiliation(s)
- P B McCray
- Departments of Pediatrics, Internal Medicine, and Occupational and Environmental Health, Howard Hughes Medical Institute, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.
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