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Airway remodeling in asthma: what really matters. Cell Tissue Res 2017; 367:551-569. [PMID: 28190087 PMCID: PMC5320023 DOI: 10.1007/s00441-016-2566-8] [Citation(s) in RCA: 253] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 12/21/2016] [Indexed: 12/21/2022]
Abstract
Airway remodeling is generally quite broadly defined as any change in composition, distribution, thickness, mass or volume and/or number of structural components observed in the airway wall of patients relative to healthy individuals. However, two types of airway remodeling should be distinguished more clearly: (1) physiological airway remodeling, which encompasses structural changes that occur regularly during normal lung development and growth leading to a normal mature airway wall or as an acute and transient response to injury and/or inflammation, which ultimately results in restoration of a normal airway structures; and (2) pathological airway remodeling, which comprises those structural alterations that occur as a result of either disturbed lung development or as a response to chronic injury and/or inflammation leading to persistently altered airway wall structures and function. This review will address a few major aspects: (1) what are reliable quantitative approaches to assess airway remodeling? (2) Are there any indications supporting the notion that airway remodeling can occur as a primary event, i.e., before any inflammatory process was initiated? (3) What is known about airway remodeling being a secondary event to inflammation? And (4), what can we learn from the different animal models ranging from invertebrate to primate models in the study of airway remodeling? Future studies are required addressing particularly pheno-/endotype-specific aspects of airway remodeling using both endotype-specific animal models and “endotyped” human asthmatics. Hopefully, novel in vivo imaging techniques will be further advanced to allow monitoring development, growth and inflammation of the airways already at a very early stage in life.
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Lucini V, Ciracì R, Dugnani S, Pannacci M, Pisati F, Caronno A, Tirone G, Scaglione F. Antibiotics counteract the worsening of airway remodelling induced by infections in asthma. Int J Antimicrob Agents 2014; 43:442-50. [PMID: 24698123 DOI: 10.1016/j.ijantimicag.2014.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 02/03/2014] [Indexed: 11/20/2022]
Abstract
Asthma is associated with structural remodelling processes, including basement membrane thickening, increased vascularity and smooth muscle alterations. It is known that respiratory infections are associated with asthma exacerbation; infections can worsen asthma symptoms and influence susceptibility to asthma onset. How infections affect asthma is not fully elucidated. It is possible that the immune response, due to recurrent infections, leads to the pathogen's eradication but also increases bronchial inflammation, which induces airway remodelling in asthmatic subjects. We evaluated how infection affects lung remodelling and inflammatory responses and assessed the impact of antibiotic treatment in a murine model of asthma. Ovalbumin-sensitised BALB/c mice were divided into control, mild and chronic asthmatics. A subset of animals in each group was infected with Streptococcus pneumoniae and was treated with antibiotics. The results show an increase in key lung remodelling factors in mice with chronic asthma, particularly those infected with S. pneumoniae. Notably, antibiotic therapy attenuated these effects. These findings demonstrate for the first time that prompt antibiotic therapy may be useful to reduce lung remodelling progression in infected asthmatic subjects.
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Affiliation(s)
- Valeria Lucini
- Department of Medical Biotechnologies and Translational Medicine, University of Milan, via Vanvitelli 32, Milan, Italy
| | - Rocco Ciracì
- Department of Medical Biotechnologies and Translational Medicine, University of Milan, via Vanvitelli 32, Milan, Italy
| | - Silvana Dugnani
- Department of Medical Biotechnologies and Translational Medicine, University of Milan, via Vanvitelli 32, Milan, Italy
| | - Marilou Pannacci
- Department of Medical Biotechnologies and Translational Medicine, University of Milan, via Vanvitelli 32, Milan, Italy
| | - Federica Pisati
- IFOM Foundation, FIRC Institute of Molecular Oncology, Milan, Italy
| | - Alessia Caronno
- IFOM Foundation, FIRC Institute of Molecular Oncology, Milan, Italy
| | - Giampaolo Tirone
- Department of Medical Biotechnologies and Translational Medicine, University of Milan, via Vanvitelli 32, Milan, Italy
| | - Francesco Scaglione
- Department of Medical Biotechnologies and Translational Medicine, University of Milan, via Vanvitelli 32, Milan, Italy.
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Wu W, Tholozan FM, Goldberg MW, Bowen L, Wu J, Quinlan RA. A gradient of matrix-bound FGF-2 and perlecan is available to lens epithelial cells. Exp Eye Res 2013; 120:10-4. [PMID: 24341990 PMCID: PMC3988982 DOI: 10.1016/j.exer.2013.12.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 12/03/2013] [Accepted: 12/05/2013] [Indexed: 11/28/2022]
Abstract
Fibroblast growth factors play a key role in regulating lens epithelial cell proliferation and differentiation via an anteroposterior gradient that exists between the aqueous and vitreous humours. FGF-2 is the most important for lens epithelial cell proliferation and differentiation. It has been proposed that the presentation of FGF-2 to the lens epithelial cells involves the lens capsule as a source of matrix-bound FGF-2. Here we used immunogold labelling to measure the matrix-bound FGF-2 gradient on the inner surface of the lens capsule in flat-mounted preparations to visualize the FGF-2 available to lens epithelial cells. We also correlated FGF-2 levels with levels of its matrix-binding partner perlecan, a heparan sulphate proteoglycan (HSPG) and found the levels of both to be highest at the lens equator. These also coincided with increased levels of phosphorylated extracellular signal-regulated kinase 1 and 2 (pERK1/2) in lens epithelial cells that localised to condensed chromosomes of epithelial cells that were Ki-67 positive. The gradient of matrix-bound FGF-2 (anterior pole: 3.7 ± 1.3 particles/μm2; equator: 8.2 ± 1.9 particles/μm2; posterior pole: 4 ± 0.9 particles/μm2) and perlecan (anterior pole: 2.1 ± 0.4 particles/μm2; equator: 5 ± 2 particles/μm2; posterior pole: 1.9 ± 0.7 particles/μm2) available at the inner lens capsule surface was measured for the bovine lens. These data support the anteroposterior gradient hypothesis and provide the first measurement of the gradient for an important morphogen and its HSPG partner, perlecan, at the epithelial cell-lens capsule interface.
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Affiliation(s)
- Weiju Wu
- Biophysical Sciences Institute, School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | | | - Martin W Goldberg
- Biophysical Sciences Institute, School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - Leon Bowen
- Biophysical Sciences Institute, Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
| | - Junjie Wu
- Biophysical Sciences Institute, School of Engineering and Computing Sciences, Durham University, Durham DH1 3LE, United Kingdom
| | - Roy A Quinlan
- Biophysical Sciences Institute, School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, United Kingdom.
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Schuliga M, Javeed A, Harris T, Xia Y, Qin C, Wang Z, Zhang X, Lee PVS, Camoretti-Mercado B, Stewart AG. Transforming growth factor-β-induced differentiation of airway smooth muscle cells is inhibited by fibroblast growth factor-2. Am J Respir Cell Mol Biol 2013; 48:346-53. [PMID: 23239497 PMCID: PMC3604085 DOI: 10.1165/rcmb.2012-0151oc] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 10/15/2012] [Indexed: 11/24/2022] Open
Abstract
In asthma, basic fibroblast growth factor (FGF-2) plays an important (patho)physiological role. This study examines the effects of FGF-2 on the transforming growth factor-β (TGF-β)-stimulated differentiation of airway smooth muscle (ASM) cells in vitro. The differentiation of human ASM cells after incubation with TGF-β (100 pM) and/or FGF-2 (300 pM) for 48 hours was assessed by increases in contractile protein expression, actin-cytoskeleton reorganization, enhancements in cell stiffness, and collagen remodeling. FGF-2 inhibited TGF-β-stimulated increases in transgelin (SM22) and calponin gene expression (n = 15, P < 0.01) in an extracellular signal-regulated kinase 1/2 (ERK1/2) signal transduction-dependent manner. The abundance of ordered α-smooth muscle actin (α-SMA) filaments formed in the presence of TGF-β were also reduced by FGF-2, as was the ratio of F-actin to G-actin (n = 8, P < 0.01). Furthermore, FGF-2 attenuated TGF-β-stimulated increases in ASM cell stiffness and the ASM-mediated contraction of lattices, composed of collagen fibrils (n = 5, P < 0.01). However, the TGF-β-stimulated production of IL-6 was not influenced by FGF-2 (n = 4, P > 0.05), suggesting that FGF-2 antagonism is selective for the regulation of ASM cell contractile protein expression, organization, and function. Another mitogen, thrombin (0.3 U ml(-1)), exerted no effect on TGF-β-regulated contractile protein expression (n = 8, P > 0.05), α-SMA organization, or the ratio of F-actin to G-actin (n = 4, P > 0.05), suggesting that the inhibitory effect of FGF-2 is dissociated from its mitogenic actions. The addition of FGF-2, 24 hours after TGF-β treatment, still reduced contractile protein expression, even when the TGF-β-receptor kinase inhibitor, SB431542 (10 μM), was added 1 hour before FGF-2. We conclude that the ASM cell differentiation promoted by TGF-β is antagonized by FGF-2. A better understanding of the mechanism of action for FGF-2 is necessary to develop a strategy for therapeutic exploitation in the treatment of asthma.
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Affiliation(s)
| | - Aqeel Javeed
- Department of Pharmacology and Toxicology, University of Veterinary and Animal Sciences, Lahore, Pakistan; and
| | | | | | | | - Zhexing Wang
- Department of Chemical and Biomolecular Engineering, and
| | - Xuehua Zhang
- Department of Chemical and Biomolecular Engineering, and
| | - Peter V. S. Lee
- Department of Mechanical Engineering, University of Melbourne, Parkville, Victoria, Australia
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Abstract
Airway epithelial healing is defined as restoration of health or soundness; to cure. Our research indicates that two types of progenitor cells participate in this process: the tissue-specific stem cell (TSC) and the facultative basal progenitor (FBP). The TSC restores the epithelium to its normal structure and function. Thus, the TSC regenerates the epithelium. In contrast, the FBP-derived epithelium is characterized by regions of cellular hyperplasia and hypoplasia. Since the FBP-derived epithelium deviates from normal, we term the FBP-mediated process repair. Our work indicates that the TSC responds to signals from other epithelial cells, including the FBP. These signals instruct the TSC to proliferate or to select one of several differentiation pathways. We interpret these data in the context of Stephen Padget's "seed and soil" paradigm. Therein, Padget explained that metastasis of a tumor, the seed, to a specific site, the soil, was determined by the growth and differentiation requirements of the tumor cell. By extending the seed and soil paradigm to airway epithelial healing, we suggest that proliferation and differentiation of the TSC, the seed, is determined by its interactions with other cell types, the soil. Based on this concept, we provide a set of suggestions for development of cell-based therapies that are directed toward chronic airways disease.
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Plopper CG, Joad JP, Miller LA, Schelegle ES, Fanucchi MV, Van Winkle LS, Tyler NK, Avdalovic MV, Evans MJ, Lasley WL, Buckpitt AR, Pinkerton KE, Tarkington BK, Davis S, Nishio SJ, Gershwin LJ, Wu R, Hyde DM. Lung effects of inhaled corticosteroids in a rhesus monkey model of childhood asthma. Clin Exp Allergy 2012; 42:1104-18. [PMID: 22702509 PMCID: PMC3913647 DOI: 10.1111/j.1365-2222.2012.04005.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The risks for infants and young children receiving inhaled corticosteroid (ICS) therapy are largely unknown. Recent clinical studies indicate that ICS therapy in pre-school children with symptoms of asthma result in decreased symptoms without influencing the clinical disease course, but potentially affect postnatal growth and development. The current study employs a primate experimental model to identify the risks posed by ICS therapy. OBJECTIVE To (1) establish whether ICS therapy in developing primate lungs reverses pulmonary pathobiology associated with allergic airway disease (AAD) and (2) define the impact of ICS on postnatal lung growth and development in primates. METHODS Infant rhesus monkeys were exposed, from 1 through 6 months, to filtered air (FA) with house dust mite allergen and ozone using a protocol that produces AAD (AAD monkeys), or to FA alone (Control monkeys). From three through 6 months, the monkeys were treated daily with ICS (budesonide) or saline. RESULTS Several AAD manifestations (airflow restrictions, lavage eosinophilia, basement membrane zone thickening, epithelial mucin composition) were reduced with ICS treatment, without adverse effects on body growth or adrenal function; however, airway branching abnormalities and intraepithelial innervation were not reduced. In addition, several indicators of postnatal lung growth and differentiation: vital capacity, inspiratory capacity, compliance, non-parenchymal lung volume and alveolarization, were increased in both AAD and Control monkeys that received ICS treatment. CONCLUSIONS AND CLINICAL RELEVANCE Incomplete prevention of pathobiological changes in the airways and disruption of postnatal growth and differentiation of airways and lung parenchyma in response to ICS pose risks for developing primate lungs. These responses also represent two mechanisms that could compromise ICS therapy's ability to alter clinical disease course in young children.
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Affiliation(s)
- C G Plopper
- Respiratory Diseases Unit, California National Primate Research Center, University of California, One Shields Ave, Davis, CA 95616, USA.
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7
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Kearley J, Erjefalt JS, Andersson C, Benjamin E, Jones CP, Robichaud A, Pegorier S, Brewah Y, Burwell TJ, Bjermer L, Kiener PA, Kolbeck R, Lloyd CM, Coyle AJ, Humbles AA. IL-9 governs allergen-induced mast cell numbers in the lung and chronic remodeling of the airways. Am J Respir Crit Care Med 2011; 183:865-75. [PMID: 20971830 PMCID: PMC3385369 DOI: 10.1164/rccm.200909-1462oc] [Citation(s) in RCA: 165] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
RATIONALE IL-9 is a pleiotropic cytokine that has multiple effects on structural as well as numerous hematopoietic cells, which are central to the pathogenesis of asthma. OBJECTIVES The contribution of IL-9 to asthma pathogenesis has thus far been unclear, due to conflicting reports in the literature. These earlier studies focused on the role of IL-9 in acute inflammatory models; here we have investigated the effects of IL-9 blockade during chronic allergic inflammation. METHODS Mice were exposed to either prolonged ovalbumin or house dust mite allergen challenge to induce chronic inflammation and airway remodeling. MEASUREMENTS AND MAIN RESULTS We found that IL-9 governs allergen-induced mast cell (MC) numbers in the lung and has pronounced effects on chronic allergic inflammation. Anti-IL-9 antibody-treated mice were protected from airway remodeling with a concomitant reduction in mature MC numbers and activation, in addition to decreased expression of the profibrotic mediators transforming growth factor-β1, vascular endothelial growth factor, and fibroblast growth factor-2 in the lung. Airway remodeling was associated with impaired lung function in the peripheral airways and this was reversed by IL-9 neutralization. In human asthmatic lung tissue, we identified MCs as the main IL-9 receptor expressing population and found them to be sources of vascular endothelial growth factor and fibroblast growth factor-2. CONCLUSIONS Our data suggest an important role for an IL-9-MC axis in the pathology associated with chronic asthma and demonstrate that an impact on this axis could lead to a reduction in chronic inflammation and improved lung function in patients with asthma.
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Affiliation(s)
- Jennifer Kearley
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD 20878, USA
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8
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Evans MJ, Fanucchi MV, Plopper CG, Hyde DM. Postnatal development of the lamina reticularis in primate airways. Anat Rec (Hoboken) 2010; 293:947-54. [PMID: 20503389 DOI: 10.1002/ar.20824] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The basement membrane zone (BMZ) appears as three component layers: the lamina lucida, lamina densa, and lamina reticularis. The laminas lucida and densa are present during all stages of development. The lamina reticularis appears during postnatal development. Collagens I, III, and V form heterogeneous fibers that account for the thickness of the lamina reticularis. Additionally, there are three proteoglycans considered as integral components of the BMZ: perlecan, collagen XVIII, and bamacan. Perlecan is the predominant heparan sulfate proteoglycan in the airway BMZ. It is responsible for many of the functions attributed to the BMZ, in particular, trafficking of growth factors and cytokines between epithelial and mesenchymal cells. Growth factor binding sites on perlecan include FGF-1, FGF-2, FGF-7, FGF-10, PDGF, HGF, HB-EGF, VEGF, and TGF-beta. Growth factors pass through the BMZ when moving between the epithelial and mesenchymal cell layers. They move by rapid reversible binding with sites on both the heparan sulfate chains and core protein of perlecan. In this manner, perlecan regulates movement of growth factors between tissues. Another function of the BMZ is storage and regulation of FGF-2. FGF-2 has been shown to be involved with normal growth and thickening of the BMZ. Thickening of the BMZ is a feature of airway remodeling in asthma. It may have a positive effect by protecting against airway narrowing and air trapping. Conversely, it may have a negative effect by influencing trafficking of growth factors in the epithelial mesenchymal trophic unit. However, currently the significance of BMZ thickening is not known.
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Affiliation(s)
- Michael J Evans
- California National Primate Research Center, University of California, Davis, California, USA.
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Cole BB, Smith RW, Jenkins KM, Graham BB, Reynolds PR, Reynolds SD. Tracheal Basal cells: a facultative progenitor cell pool. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 177:362-76. [PMID: 20522644 DOI: 10.2353/ajpath.2010.090870] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Analysis of lineage relationships in the naphthalene-injured tracheal epithelium demonstrated that two multipotential keratin 14-expressing cells (K14ECs) function as progenitors for Clara and ciliated cells. These K14EC were distinguished by their self-renewal capacity and were hypothesized to reside at the stem and transit amplifying tiers of a tissue-specific stem cell hierarchy. In this study, we used gene expression and histomorphometric analysis of the steady-state and naphthalene-injured trachea to evaluate the predictions of this model. We found that the steady-state tracheal epithelium is maintained by two progenitor cell pools, secretory and basal cells, and the latter progenitor pool is further divided into two subsets, keratin 14-negative and -positive. After naphthalene-mediated depletion of the secretory and ciliated cell types, the two basal cell pools coordinate to restore the epithelium. Both basal cell types up-regulate keratin 14 and generate a broadly distributed, abundant, and highly mitotic cell pool. Furthermore, basal cell proliferation is associated with generation of differentiated Clara and ciliated cells. The uniform distribution of basal cell progenitors and of their differentiated progeny leads us to propose that the hierarchical organization of tracheal reparative cells be revised to include a facultative basal cell progenitor pool.
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Affiliation(s)
- Brook B Cole
- Department of Pediatrics, Division of Cell Biology, National Jewish Health, Denver, Colorado, USA
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Evans MJ, Fanucchi MV, Miller LA, Carlson MA, Nishio SJ, Hyde DM. Reduction of collagen VII anchoring fibrils in the airway basement membrane zone of infant rhesus monkeys exposed to house dust mite. Am J Physiol Lung Cell Mol Physiol 2010; 298:L543-7. [PMID: 20139177 DOI: 10.1152/ajplung.00337.2009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Collagen VII anchoring fibrils in the basement membrane zone (BMZ) are part of a supracellular anchoring network that attaches the epithelium to the BMZ. Sloughing of airway epithelium in asthmatics (creola bodies) is a pathology associated with the supracellular anchoring network. In a rhesus monkey model of house dust mite (HDM)-induced allergic asthma, we found increased deposition of collagen I in the BMZ. In this study, we determine whether HDM also affected deposition of collagen VII in the BMZ. In the developing airway of rhesus monkeys, the width of collagen VII anchoring fibrils in the BMZ was 0.02 +/- 0.04 microm at 1 mo of age. At 6 mo the width had increased to 1.28 +/- 0.34 microm and at 12 mo 2.15 +/- 0.13 microm. In animals treated with HDM, we found a 42.2% reduction in the width of collagen VII layer in the BMZ at 6 mo (0.74 +/- 0.15 microm; P < 0.05). During recovery, the rate of collagen VII deposition returned to normal. However, the amount of collagen VII lost was not recovered after 6 mo. We concluded that normal development of the collagen VII attachment between the epithelium and BMZ occurs in coordination with development of the BMZ. However, in HDM-treated animals, the collagen VII attachment with the epithelium was significantly reduced. Such a reduction in collagen VII may weaken the supracellular anchoring network and be associated with sloughing of the epithelium and formation of creola bodies in asthmatics.
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Affiliation(s)
- Michael J Evans
- California National Primate Research Center and Center for Comparative Respiratory Biology and Medicine, Universitof California, Davis, California 95616, USA.
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Tourdot S, Mathie S, Hussell T, Edwards L, Wang H, Openshaw PJM, Schwarze J, Lloyd CM. Respiratory syncytial virus infection provokes airway remodelling in allergen-exposed mice in absence of prior allergen sensitization. Clin Exp Allergy 2008; 38:1016-24. [PMID: 18498543 PMCID: PMC3385350 DOI: 10.1111/j.1365-2222.2008.02974.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND The mechanisms underlying exacerbation of asthma induced by respiratory syncytial virus (RSV) infection have been extensively studied in human and animal models. However, most of these studies focused on acute inflammation and little is known of its long-term consequences on remodelling of the airway tissue. OBJECTIVE The aim of the study was to use a murine model of prolonged allergen-induced airway inflammation to investigate the effect of RSV infection on allergic airway inflammation and tissue remodelling. METHODS We subjected mice to RSV infection before or during the chronic phase of airway challenges with OVA and compared parameters of airway inflammation and remodelling at the end-point of the prolonged allergen-induced airway inflammation protocol. RESULTS RSV infection did not affect the severity of airway inflammation in any of the groups studied. However, RSV infection provoked airway remodelling in non-sensitized, allergen-challenged mice that did not otherwise develop any of the features of allergic airways disease. Increased collagen synthesis in the lung and thickening of the bronchial basal membrane was observed in non-sensitized allergen-challenged mice only after prior RSV infection. In addition, fibroblast growth factor (FGF)-2 but not TGF-beta(1) was increased in this group following RSV infection. CONCLUSION Our data show for the first time that RSV infection can prime the lung of mice that are not previously systemically sensitized, to develop airway remodelling in response to allergen upon sole exposure via the airways. Moreover, our results implicate RSV-induced FGF-2 in the remodelling process in vivo.
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Affiliation(s)
- S Tourdot
- Leukocyte Biology Section, National Heart and Lung Institute, Imperial College London, South Kensington Campus, London, UK
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Abstract
This review evaluates the current status of information regarding the nonhuman primate as an experimental model for defining mechanisms of chronic airways disease in humans, using the concept of the epithelial-mesenchymal trophic unit (EMTU) as a basis for comparison with other laboratory species. All of the cellular and acellular compartments within the walls of tracheobronchial airways which interact as the EMTU are present throughout the airway tree in human and nonhuman primates. The epithelial compartment contains mucous goblet and basal cells in the surface epithelium and submucosal glands within the wall. The interstitial compartment of primates has a prominent subepithelial basement membrane zone (BMZ) with an attenuated fibroblast sheath and cartilage throughout the tree. In primates, there is an extensive transition zone between distal conducting airways and lung parenchyma composed of numerous generations of respiratory bronchioles. None of these features are characteristic of intrapulmonary airways in rodents, whose airways do share ciliated cells, smooth muscle cells, nerve networks, vasculature and inflammatory cell populations with primates. While the numbers of intrapulmonary airway branches are similar for most mammals, branching patterns, which dictate distribution of inhaled materials, are more uniform (dichotomous) in primates and less so (monopodial) in rodents. Development of tracheobronchial airways (both differentiation of the EMTU and overall growth) occurs over an extensive postnatal period (months to years) in primates and a comparably shorter time period (2-3 weeks) in rodents. As with allergic airways disease in humans, experimental exposure of nonhuman primates to a known human allergen, house dust mite, produces extensive remodeling of all compartments of the EMTU: mucous goblet cell hyperplasia, epithelial sloughing, basement membrane zone (BMZ) thickening and reorganization, altered attenuated fibroblast function, subepithelial fibrosis and smooth muscle thickening. Experimental allergic airways disease in nonhuman primates also shares other features with asthmatic humans: positive skin test to allergen; allergen-specific circulating IgE; airway hyper responsiveness to allergen, histamine and methacholine; increased eosinophils, IGE positive cells and mucins in airway exudate; and migratory leukocyte accumulations in the airway wall and lumen. Experimental exposure of nonhuman primates to reactive gases, such as ozone, produces the chronic respiratory bronchiolitis and other airway alterations associated with restricted airflow and chronic respiratory bronchiolitis characteristic of COPD in young smokers. We conclude that nonhuman primate models are appropriate for defining mechanisms as they relate to allergic airways disease and COPD in humans.
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Affiliation(s)
- Charles G Plopper
- California National Primate Research Center and School of Veterinary Medicine, University of California, One Shields Avenue, Davis, CA 95616, USA.
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13
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Bossé Y, Thompson C, Audette K, Stankova J, Rola-Pleszczynski M. Interleukin-4 and interleukin-13 enhance human bronchial smooth muscle cell proliferation. Int Arch Allergy Immunol 2008; 146:138-48. [PMID: 18204280 DOI: 10.1159/000113517] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Accepted: 09/18/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND T(H)2 inflammation and bronchial smooth muscle cell (BSMC) hyperplasia are characteristic features of asthma, but whether these phenomena are linked remains unknown. This study aims to define the effect of the T(H)2 cytokines IL-4 and IL-13 on human BSMC proliferation when administered alone or in combination with the fibroblast growth factor 2 (FGF2) growth factor. In addition, the effects of the proinflammatory mediators TNFalpha and IL-1 beta and the involvement of members of the well-known family of platelet-derived growth factor (PDGF) mitogens were tested. METHODS BSMC proliferation was measured by crystal violet staining and PDGF and PDGF receptor (PDGFR) expression were determined by RT-PCR, immunocytochemistry, ELISA, flow cytometry and dot plot analysis. RESULTS Neither IL-4 nor IL-13 alone induced BSMC proliferation, despite both being potent inducers of PDGF-CC. However, following a pretreatment with FGF2, which increased PDGFR alpha chain expression, both IL-4 and IL-13 increased FGF2-induced BSMC proliferation in a time- and concentration-dependent manner. TNFalpha and IL-1 beta did not affect basal or FGF2-induced BSMC proliferation, but both proinflammatory mediators enhanced the proliferative synergism between FGF2 and the T(H)2 cytokines. CONCLUSIONS IL-4 and IL-13 potently induce FGF2-primed BSMC proliferation via an autocrine loop involving PDGFRalpha and PDGF-CC, and this proliferative synergism is amplified by proinflammatory cytokines.
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Affiliation(s)
- Ynuk Bossé
- Immunology Division, Department of Pediatrics, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, Canada
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14
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Bossé Y, Rola-Pleszczynski M. FGF2 in asthmatic airway-smooth-muscle-cell hyperplasia. Trends Mol Med 2007; 14:3-11. [PMID: 18055262 DOI: 10.1016/j.molmed.2007.11.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 11/09/2007] [Accepted: 11/09/2007] [Indexed: 01/25/2023]
Abstract
Airway smooth muscle (ASM)-cell hyperplasia is a cardinal feature of the remodeled airways in asthma and contributes to airway hyper-responsiveness. Several upregulated mediators are potentially involved in this architectural change. Recently, many investigators have turned their interest toward fibroblast growth factor (FGF)2. This opinion article describes the current knowledge on the biology of this growth factor, reviews the papers that have measured its baseline or allergen-induced expression in human asthmatics and summarizes observations supporting its role as an ASM cell mitogen. The possibility that FGF2 is involved in ASM-cell hyperplasia is raised, not only because it induces ASM-cell proliferation by itself but because of recent findings showing that FGF2 confers to ASM cells the ability to proliferate in response to different asthma mediators.
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Affiliation(s)
- Ynuk Bossé
- Immunology Division, Department of Pediatrics, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada.
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15
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Fanucchi MV, Plopper CG, Evans MJ, Hyde DM, Van Winkle LS, Gershwin LJ, Schelegle ES. Cyclic exposure to ozone alters distal airway development in infant rhesus monkeys. Am J Physiol Lung Cell Mol Physiol 2006; 291:L644-50. [PMID: 16648242 DOI: 10.1152/ajplung.00027.2006] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Inner city children exposed to high levels of ozone suffer from an increased prevalence of respiratory diseases. Lung development in children is a long-term process, and there is a significant period of time during development when children growing up in urban areas are exposed to oxidant air pollution. This study was designed to test whether repeating cycles of injury and repair caused by episodes of ozone exposure lead to chronic airway disease and decreased lung function by altering normal lung maturation. We evaluated postnatal lung morphogenesis and function of infant monkeys after 5 mo of episodic exposure of 0.5 parts per million ozone beginning at 1 mo of age. Nonhuman primates were chosen because their airway structure and postnatal lung development is similar to those of humans. Airway morphology and structure were evaluated at the end of the 5-mo exposure period. Compared with control infants, ozone-exposed animals had four fewer nonalveolarized airway generations, hyperplastic bronchiolar epithelium, and altered smooth muscle bundle orientation in terminal and respiratory bronchioles. These results suggest that episodic exposure to environmental ozone compromises postnatal morphogenesis of tracheobronchial airways.
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Affiliation(s)
- Michelle V Fanucchi
- Center for Comparative REspiratory Biology and Medicine, California National Primate Research Center, University of California, Davis, CA 95616, USA.
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Kajekar R, Pieczarka EM, Smiley-Jewell SM, Schelegle ES, Fanucchi MV, Plopper CG. Early postnatal exposure to allergen and ozone leads to hyperinnervation of the pulmonary epithelium. Respir Physiol Neurobiol 2006; 155:55-63. [PMID: 16616710 DOI: 10.1016/j.resp.2006.03.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Revised: 03/01/2006] [Accepted: 03/02/2006] [Indexed: 11/21/2022]
Abstract
Airway injury in infant monkeys exposed to ozone and/or house dust mite allergen (HDMA) is associated with a loss of epithelial innervation. In this study, we evaluated for persistence/recovery of the altered epithelial innervation. Thirty-day-old rhesus monkeys were exposed to repeated episodes of HDMA and/or ozone from 1 to 6 months of age and subsequently allowed to recover for 6 months in the absence of further ozone exposure and/or minimal HDMA challenge (sufficient to maintain allergen sensitization). At 1 year of age, nerve density in intrapulmonary airways was immunohistochemically evaluated using antibodies directed against protein gene product 9.5. Hyperinnervation and irregular epithelial nerve distribution was observed in both HDMA- and ozone-exposed groups; most prominent alterations were observed in animals exposed to HDMA plus ozone. Therefore, while adaptive mechanisms exist that re-establish epithelial innervation following cessation or diminution of exposure to HDMA and/or ozone, the recovery is associated with persistent proliferative mechanisms that result in hyperinnervation of the airways.
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Affiliation(s)
- Radhika Kajekar
- Center for Comparative Respiratory Biology and Medicine, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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17
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Bossé Y, Thompson C, Stankova J, Rola-Pleszczynski M. Fibroblast growth factor 2 and transforming growth factor beta1 synergism in human bronchial smooth muscle cell proliferation. Am J Respir Cell Mol Biol 2006; 34:746-53. [PMID: 16439802 DOI: 10.1165/rcmb.2005-0309oc] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Bronchial smooth muscle cell (BSMC) hyperplasia is a typical feature of airway remodeling and contributes to airway obstruction and hyperresponsiveness in asthma. Fibroblast growth factor 2 (FGF-2) and transforming growth factor beta1 (TGF-beta1) are sequentially upregulated in asthmatic airways after allergic challenge. Whereas FGF-2 induces BSMC proliferation, the mitogenic effect of TGF-beta1 remains controversial, and the effect of sequential FGF-2 and TGF-beta1 co-stimulation on BSMC proliferation is unknown. This study aimed to assess the individual and sequential cooperative effects of FGF-2 and TGF-beta1 on human BSMC proliferation and define the underlying mechanisms. Mitogenic response was measured using crystal violet staining and [3H]-thymidine incorporation. Steady-state mRNA and protein levels were measured by semiquantitative RT-PCR, Western blot, and ELISA, respectively. TGF-beta1 (0.1-20 ng/ml) alone had no effect on BSMC proliferation, but increased the proliferative effect of FGF-2 (2 ng/ml) in a concentration-dependent manner (up to 6-fold). Two distinct platelet-derived growth factor receptor (PDGFR) inhibitors, AG1296 and Inhibitor III, as well as a neutralizing Ab against PDGFRalpha, partially blocked the synergism between these two growth factors. In this regard, TGF-beta1 increased PDGF-A and PDGF-C mRNA expression as well as PDGF-AA protein expression. Moreover, FGF-2 pretreatment increased the mRNA and protein expression of PDGFRalpha and the proliferative effect of exogenous PDGF-AA (140%). Our data suggest that FGF-2 and TGF-beta1 synergize in BSMC proliferation and that this synergism is partially mediated by a PDGF loop, where FGF-2 and TGF-beta1 upregulate the receptor (PDGFRalpha) and the ligands (PDGF-AA and PDGF-CC), respectively. This powerful synergistic effect may thus contribute to the hyperplastic phenotype of BSMC in remodeled asthmatic airways.
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Affiliation(s)
- Ynuk Bossé
- Immunology Division, Department of Pediatrics, Faculty of Medicine, Université de Sherbrooke, Canada
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18
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Snibson KJ, Bischof RJ, Slocombe RF, Meeusen EN. Airway remodelling and inflammation in sheep lungs after chronic airway challenge with house dust mite. Clin Exp Allergy 2005; 35:146-52. [PMID: 15725184 DOI: 10.1111/j.1365-2222.2005.02137.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Remodelling of airway walls is a significant morbidity factor in patients suffering from chronic asthma. The relationship between airway remodelling and the inflammatory response is not well defined. Sheep have been used extensively to model airway disease in humans and represent a suitable model to examine airway remodelling. OBJECTIVE The aim of the present study was to develop a model for airway remodelling in sheep after repeated challenge with a relevant human allergen to assess the relationship of airway remodelling with inflammation. METHODS Repeated challenges of house dust mite (HDM) extract or saline (control) were administered to local lung segments of sheep for a period of 6 months. After the last challenge, lung tissues from both challenged and unchallenged lung compartments of the same sheep were compared using morphometric image analysis and (immuno) histological studies. RESULTS All HDM-challenged sheep developed significant bronchoalveolar lavage eosinophilia during challenge. At the end of the challenge period, significant increases in airway collagen and airway smooth muscle content were found in a proportion (3/7) of the HDM-challenged sheep. Hyperplasia of goblet cells and epithelial cells were observed in small bronchi and bronchioles exposed to allergen. Irrespective of airway remodelling changes, all HDM-challenged, but no saline-challenged sheep, displayed significant increases in mast cells in alveolar septa and airway walls of challenged lungs compared with untreated lung compartments of the same sheep. Significant increases were also observed in CD5 and gamma delta T cell subpopulations in all allergen-exposed lung parenchyma. CONCLUSION A proportion of atopic sheep develop typical airway remodelling changes after chronic allergen challenge, which is not directly related to the level of allergic inflammation.
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Affiliation(s)
- K J Snibson
- Centre for Animal Biotechnology, School of Veterinary Science, The University of Melbourne, Parkville, Vic., Australia.
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Fanucchi MV, Schelegle ES, Baker GL, Evans MJ, McDonald RJ, Gershwin LJ, Raz E, Hyde DM, Plopper CG, Miller LA. Immunostimulatory oligonucleotides attenuate airways remodeling in allergic monkeys. Am J Respir Crit Care Med 2004; 170:1153-7. [PMID: 15306532 PMCID: PMC3927836 DOI: 10.1164/rccm.200404-533oc] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
To determine whether inhaled immunostimulatory DNA sequence oligonucleotides containing CpG motifs mitigate the pathophysiologic manifestation of the asthmatic phenotype (airways hyperresponsiveness and airways remodeling), rhesus monkeys with experimentally induced allergic airways disease were treated seven times with inhaled immunostimulatory oligonucleotides (or sham) periodically for 33 weeks. Airways hyperresponsiveness was reduced twofold in immunostimulatory DNA sequence-treated compared with sham-treated monkeys. Airways from immunostimulatory oligonucleotide-treated monkeys had thinner reticular basement membranes, fewer mucous cells, fewer eosinophils, and fewer mast cells than sham-treated allergic monkeys. We conclude that inhaled immunostimulatory oligonucleotides can attenuate the magnitude of airway hyperreactivity and airways remodeling produced in nonhuman primates with experimentally induced allergic airways disease.
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Affiliation(s)
- Michelle V Fanucchi
- Department of Anatomy, Physiology and Cell Biology, University of California, School of Veterinary Medicine, One Shields Avenue, Davis, CA 95616, USA.
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20
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Evans MJ, Fanucchi MV, Baker GL, Van Winkle LS, Pantle LM, Nishio SJ, Schelegle ES, Gershwin LJ, Miller LA, Hyde DM, Plopper CG. The remodelled tracheal basement membrane zone of infant rhesus monkeys after 6 months of recovery. Clin Exp Allergy 2004; 34:1131-6. [PMID: 15248862 DOI: 10.1111/j.1365-2222.2004.02004.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND In previous studies, we showed that repeated exposure to (1) house dust mite allergen (HDMA) (Dermatophagoides farinae) caused thickening of the basement membrane zone (BMZ) and (2) HDMA+ozone (O3) caused depletion of BMZ perlecan and atypical development of BMZ collagen (irregular thin areas<2.0 microm in width). OBJECTIVE The purpose of this study was to determine if these remodelling changes were reversible after 6 months of recovery. METHODS Rhesus monkeys were exposed to a regimen of HDMA and or O3 or filtered air (FA) for 6 months. After the exposure protocol was completed FA and O3 groups were allowed to recover in FA for 6 months. The HDMA and HDMA+O3 exposure groups recovered in a modified environment. They were re-exposed to HDMA aerosol for 2 h at monthly intervals during recovery in order to maintain sensitization for pulmonary function testing. To detect structural changes in the BMZ, collagen I and perlecan immunoreactivity were measured and compared to data from the previous papers. RESULTS The remodelled HDMA group had a significantly thicker BMZ and after 6 months of recovery the width had not regressed. In the remodelled BMZ of the HDMA+O3 group, perlecan had returned to the BMZ after 6 months of the recovery protocol, and the thin, irregular, collagen BMZ had been resolved. CONCLUSION In summary, this study has shown that: (1) The width of the remodelled HDMA BMZ did not regress during a recovery protocol that included a sensitizing dose of HDMA. (2) The atypical collagen BMZ in the HDMA+O3 BMZ was resolved in the absence of O3. (3) Depletion of perlecan from the BMZ by O3 was reversed by recovery in the absence of O3.
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Affiliation(s)
- M J Evans
- Department of Anatomy, Physiology & Cell Biology; Center for Comparative Respiratory Biology and Medicine, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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Larson SD, Schelegle ES, Walby WF, Gershwin LJ, Fanuccihi MV, Evans MJ, Joad JP, Tarkington BK, Hyde DM, Plopper CG. Postnatal remodeling of the neural components of the epithelial-mesenchymal trophic unit in the proximal airways of infant rhesus monkeys exposed to ozone and allergen. Toxicol Appl Pharmacol 2004; 194:211-20. [PMID: 14761677 DOI: 10.1016/j.taap.2003.09.025] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2003] [Accepted: 09/23/2003] [Indexed: 02/07/2023]
Abstract
Nerves and neuroendocrine cells located within the airway epithelium are ideally situated to sample a changing airway environment, to transmit that information to the central nervous system, and to promote trophic interactions between epithelial and mesenchymal cellular and acellular components. We tested the hypothesis that the environmental stresses of ozone (O(3)) and house dust mite allergen (HDMA) in atopic infant rhesus monkeys alter the distribution of airway nerves. Midlevel bronchi and bronchioles from 6-month-old infant monkeys that inhaled filtered air (FA), house dust mite allergen HDMA, O(3), or HDMA + O(3) for 11 episodes (5 days each, 0.5 ppm O(3), 8 h/day followed by 9 days recovery) were examined using immunohistochemistry for the presence of Protein gene product 9.5 (PGP 9.5), a nonspecific neural indicator, and calcitonin gene-related peptide (CGRP). Along the axial path between the sixth and the seventh intrapulmonary airway generations, there were small significant (P < 0.05) decrements in the density of epithelial nerves in monkeys exposed to HDMA or O(3), while in monkeys exposed to HDMA + O(3) there was a greater significant (P < 0.05) reduction in epithelial innervation. In animals exposed to O(3) or HDMA + O(3) there was a significant increase in the number of PGP 9.5 positive/CGRP negative cells that were anchored to the basal lamina and emitted projections in primarily the lateral plain and often intertwined with projections and cell bodies of other similar cells. We conclude that repeated cycles of acute injury and repair associated with the episodic pattern of ozone and allergen exposure alter the normal development of neural innervation of the epithelial compartment and the appearance of a new population of undefined PGP 9.5 positive cells within the epithelium.
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Affiliation(s)
- Shawnessy D Larson
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California-Davis, 1 Shields Avenue, Davis, CA 95616, USA
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Evans MJ, Fanucchi MV, Baker GL, Van Winkle LS, Pantle LM, Nishio SJ, Schelegle ES, Gershwin LJ, Miller LA, Hyde DM, Sannes PL, Plopper CG. Atypical development of the tracheal basement membrane zone of infant rhesus monkeys exposed to ozone and allergen. Am J Physiol Lung Cell Mol Physiol 2003; 285:L931-9. [PMID: 12832283 DOI: 10.1152/ajplung.00175.2003] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Development of the basement membrane zone (BMZ) occurs postnatally in the rhesus monkey. The purpose of this study was to determine whether house dust mite allergen (HDMA) plus ozone altered this process. Rhesus monkeys were exposed to a regimen of HDMA and/or ozone or filtered air for 6 mo. To detect structural changes in the BMZ, we measured immunoreactivity of collagen I. To detect functional changes in the BMZ, we measured perlecan and fibroblast growth factor-2 (FGF-2). We also measured components of the FGF-2 ternary signaling complex [fibroblast growth factor receptor-1 (FGFR-1) and syndecan-4]. The width of the BMZ was irregular in the ozone groups, suggesting atypical development of the BMZ. Perlecan was also absent from the BMZ. In the absence of perlecan, FGF-2 was not bound to the BMZ. However, FGF-2 immunoreactivity was present in basal cells, the lateral intercellular space (LIS), and attenuated fibroblasts. FGFR-1 immunoreactivity was downregulated, and syndecan-4 immunoreactivity was upregulated in the basal cells. This suggests that FGF-2 in basal cells and LIS may be bound to the syndecan-4. We conclude that ozone and HDMA plus ozone effected incorporation of perlecan into the BMZ, resulting in atypical development of the BMZ. These changes are associated with specific alterations in the regulation of FGF-2, FGFR-1, and syndecan-4 in the airway epithelial-mesenchymal trophic unit, which may be associated with the developmental problems of lungs associated with exposure to ozone.
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Affiliation(s)
- Michael J Evans
- Dept. of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, Univ. of California, Davis, CA 95616, USA.
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