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Sun R, Pan X, Ward E, Intrevado R, Morozan A, Lauzon AM, Martin JG. Serum Response Factor Expression in Excess Permits a Dual Contractile-Proliferative Phenotype of Airway Smooth Muscle. Am J Respir Cell Mol Biol 2024; 71:182-194. [PMID: 38775474 DOI: 10.1165/rcmb.2024-0081oc] [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: 02/20/2024] [Accepted: 04/18/2024] [Indexed: 08/02/2024] Open
Abstract
The transcription factors (TFs) MyoCD (myocardin) and Elk-1 (ETS Like-1 protein) competitively bind to SRF (serum response factor) and control myogenic- and mitogenic-related gene expression in smooth muscle, respectively. Their functions are therefore mutually inhibitory, which results in a contractile-versus-proliferative phenotype dichotomy. Airway smooth muscle cell (ASMC) phenotype alterations occur in various inflammatory airway diseases, promoting pathological remodeling and contributing to airflow obstruction. We characterized MyoCD and Elk-1 interactions and their roles in phenotype determination in human ASMCs. MyoCD overexpression in ASMCs increased smooth muscle gene expression, force generation, and partially restored the loss of smooth muscle protein associated with prolonged culturing while inhibiting Elk-1 transcriptional activities and proliferation induced by EGF (epidermal growth factor). However, MyoCD overexpression failed to suppress these responses induced by FBS, as FBS also upregulated SRF expression to a degree that allowed unopposed function of both TFs. Inhibition of the RhoA pathway reversed said SRF changes, allowing inhibition of Elk-1 by MyoCD overexpression and suppressing FBS-mediated contractile protein gene upregulation. Our study confirmed that MyoCD in increased abundance can competitively inhibit Elk-1 function. However, SRF upregulation permits a dual contractile-proliferative ASMC phenotype that is anticipated to exacerbate pathological alterations, whereas therapies targeting SRF may inhibit pathological ASMC proliferation and contractile protein gene expression.
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Affiliation(s)
- Rui Sun
- Meakins-Christie Laboratories, The Research Institute of McGill University Health Centre, Montréal, Québec, Canada
| | - Xingning Pan
- Meakins-Christie Laboratories, The Research Institute of McGill University Health Centre, Montréal, Québec, Canada
| | - Erin Ward
- Meakins-Christie Laboratories, The Research Institute of McGill University Health Centre, Montréal, Québec, Canada
| | - Rafael Intrevado
- Meakins-Christie Laboratories, The Research Institute of McGill University Health Centre, Montréal, Québec, Canada
| | - Arina Morozan
- Meakins-Christie Laboratories, The Research Institute of McGill University Health Centre, Montréal, Québec, Canada
| | - Anne-Marie Lauzon
- Meakins-Christie Laboratories, The Research Institute of McGill University Health Centre, Montréal, Québec, Canada
| | - James G Martin
- Meakins-Christie Laboratories, The Research Institute of McGill University Health Centre, Montréal, Québec, Canada
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Tan YH, Wang KCW, Chin IL, Sanderson RW, Li J, Kennedy BF, Noble PB, Choi YS. Stiffness Mediated-Mechanosensation of Airway Smooth Muscle Cells on Linear Stiffness Gradient Hydrogels. Adv Healthc Mater 2024; 13:e2304254. [PMID: 38593989 DOI: 10.1002/adhm.202304254] [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: 12/01/2023] [Revised: 03/28/2024] [Indexed: 04/11/2024]
Abstract
In obstructive airway diseases such as asthma and chronic obstructive pulmonary disease (COPD), the extracellular matrix (ECM) protein amount and composition of the airway smooth muscle (ASM) is often remodelled, likely altering tissue stiffness. The underlying mechanism of how human ASM cell (hASMC) mechanosenses the aberrant microenvironment is not well understood. Physiological stiffnesses of the ASM were measured by uniaxial compression tester using porcine ASM layers under 0, 5 and 10% longitudinal stretch above in situ length. Linear stiffness gradient hydrogels (230 kPa range) were fabricated and functionalized with ECM proteins, collagen I (ColI), fibronectin (Fn) and laminin (Ln), to recapitulate the above-measured range of stiffnesses. Overall, hASMC mechanosensation exhibited a clear correlation with the underlying hydrogel stiffness. Cell size, nuclear size and contractile marker alpha-smooth muscle actin (αSMA) expression showed a strong correlation to substrate stiffness. Mechanosensation, assessed by Lamin-A intensity and nuc/cyto YAP, exhibited stiffness-mediated behaviour only on ColI and Fn-coated hydrogels. Inhibition studies using blebbistatin or Y27632 attenuated most mechanotransduction-derived cell morphological responses, αSMA and Lamin-A expression and nuc/cyto YAP (blebbistatin only). This study highlights the interplay and complexities between stiffness and ECM protein type on hASMC mechanosensation, relevant to airway remodelling in obstructive airway diseases.
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Affiliation(s)
- Yong Hwee Tan
- School of Human Sciences, The University of Western Australia, Perth, WA, 6009, Australia
| | - Kimberley C W Wang
- School of Human Sciences, The University of Western Australia, Perth, WA, 6009, Australia
- Telethon Kids Institute, The University of Western Australia, Nedlands, WA, 6009, Australia
| | - Ian L Chin
- School of Human Sciences, The University of Western Australia, Perth, WA, 6009, Australia
| | - Rowan W Sanderson
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Perth, WA, 6009, Australia
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, Perth, WA, 6009, Australia
| | - Jiayue Li
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Perth, WA, 6009, Australia
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, Perth, WA, 6009, Australia
| | - Brendan F Kennedy
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Perth, WA, 6009, Australia
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, Perth, WA, 6009, Australia
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Grudziadzka 5, Torun, 87-100, Poland
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Perth, WA, 6009, Australia
| | - Yu Suk Choi
- School of Human Sciences, The University of Western Australia, Perth, WA, 6009, Australia
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Nizamoglu M, Burgess JK. Current possibilities and future opportunities provided by three-dimensional lung ECM-derived hydrogels. Front Pharmacol 2023; 14:1154193. [PMID: 36969853 PMCID: PMC10034771 DOI: 10.3389/fphar.2023.1154193] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 02/28/2023] [Indexed: 03/11/2023] Open
Abstract
Disruption of the complex interplay between cells and extracellular matrix (ECM), the scaffold that provides support, biochemical and biomechanical cues, is emerging as a key element underlying lung diseases. We readily acknowledge that the lung is a flexible, relatively soft tissue that is three dimensional (3D) in structure, hence a need exists to develop in vitro model systems that reflect these properties. Lung ECM-derived hydrogels have recently emerged as a model system that mimics native lung physiology; they contain most of the plethora of biochemical components in native lung, as well as reflecting the biomechanics of native tissue. Research investigating the contribution of cell:matrix interactions to acute and chronic lung diseases has begun adopting these models but has yet to harness their full potential. This perspective article provides insight about the latest advances in the development, modification, characterization and utilization of lung ECM-derived hydrogels. We highlight some opportunities for expanding research incorporating lung ECM-derived hydrogels and potential improvements for the current approaches. Expanding the capabilities of investigations using lung ECM-derived hydrogels is positioned at a cross roads of disciplines, the path to new and innovative strategies for unravelling disease underlying mechanisms will benefit greatly from interdisciplinary approaches. While challenges need to be addressed before the maximum potential can be unlocked, with the rapid pace at which this field is evolving, we are close to a future where faster, more efficient and safer drug development targeting the disrupted 3D microenvironment is possible using lung ECM-derived hydrogels.
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Affiliation(s)
- Mehmet Nizamoglu
- University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Groningen, Netherlands
- University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD (GRIAC), Groningen, Netherlands
| | - Janette K. Burgess
- University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Groningen, Netherlands
- University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD (GRIAC), Groningen, Netherlands
- University of Groningen, University Medical Center Groningen, W.J. Kolff Institute for Biomedical Engineering and Materials Science-FB41, Groningen, Netherlands
- *Correspondence: Janette K. Burgess,
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Amrani Y, Panettieri RA, Ramos-Ramirez P, Schaafsma D, Kaczmarek K, Tliba O. Important lessons learned from studies on the pharmacology of glucocorticoids in human airway smooth muscle cells: Too much of a good thing may be a problem. Pharmacol Ther 2020; 213:107589. [PMID: 32473159 DOI: 10.1016/j.pharmthera.2020.107589] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 05/18/2020] [Indexed: 12/12/2022]
Abstract
Glucocorticoids (GCs) are the treatment of choice for chronic inflammatory diseases such as asthma. Despite proven effective anti-inflammatory and immunosuppressive effects, long-term and/or systemic use of GCs can potentially induce adverse effects. Strikingly, some recent experimental evidence suggests that GCs may even exacerbate some disease outcomes. In asthma, airway smooth muscle (ASM) cells are among the targets of GC therapy and have emerged as key contributors not only to bronchoconstriction, but also to airway inflammation and remodeling, as implied by experimental and clinical evidence. We here will review the beneficial effects of GCs on ASM cells, emphasizing the differential nature of GC effects on pro-inflammatory genes and on other features associated with asthma pathogenesis. We will also summarize evidence describing how GCs can potentially promote pro-inflammatory and remodeling features in asthma with a specific focus on ASM cells. Finally, some of the possible solutions to overcome these unanticipated effects of GCs will be discussed.
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Affiliation(s)
- Yassine Amrani
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, Leicester Biomedical Research Center Respiratory, Leicester, UK
| | - Reynold A Panettieri
- Department of Medicine, Rutgers Institute for Translational Medicine and Science, Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Patricia Ramos-Ramirez
- Department of Biomedical Sciences, College of Veterinary Medicine, Long Island University, Brookville, NY, USA
| | | | - Klaudia Kaczmarek
- Department of Biomedical Sciences, College of Veterinary Medicine, Long Island University, Brookville, NY, USA
| | - Omar Tliba
- Department of Medicine, Rutgers Institute for Translational Medicine and Science, Robert Wood Johnson Medical School, New Brunswick, NJ, USA; Department of Biomedical Sciences, College of Veterinary Medicine, Long Island University, Brookville, NY, USA.
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Functional phenotype of airway myocytes from asthmatic airways. Pulm Pharmacol Ther 2012; 26:95-104. [PMID: 22921313 DOI: 10.1016/j.pupt.2012.08.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Revised: 08/08/2012] [Accepted: 08/08/2012] [Indexed: 11/23/2022]
Abstract
In asthma, the airway smooth muscle (ASM) cell plays a central role in disease pathogenesis through cellular changes which may impact on its microenvironment and alter ASM response and function. The answer to the long debated question of what makes a 'healthy' ASM cell become 'asthmatic' still remains speculative. What is known of an 'asthmatic' ASM cell, is its ability to contribute to the hallmarks of asthma such as bronchoconstriction (contractile phenotype), inflammation (synthetic phenotype) and ASM hyperplasia (proliferative phenotype). The phenotype of healthy or diseased ASM cells or tissue for the most part is determined by expression of key phenotypic markers. ASM is commonly accepted to have different phenotypes: the contractile (differentiated) state versus the synthetic (dedifferentiated) state (with the capacity to synthesize mediators, proliferate and migrate). There is now accumulating evidence that the synthetic functions of ASM in culture derived from asthmatic and non-asthmatic donors differ. Some of these differences include an altered profile and increased production of extracellular matrix proteins, pro-inflammatory mediators and adhesion receptors, collectively suggesting that ASM cells from asthmatic subjects have the capacity to alter their environment, actively participate in repair processes and functionally respond to changes in their microenvironment.
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Dekkers BGJ, Bos IST, Zaagsma J, Meurs H. Functional consequences of human airway smooth muscle phenotype plasticity. Br J Pharmacol 2012; 166:359-67. [PMID: 22053853 DOI: 10.1111/j.1476-5381.2011.01773.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Airway smooth muscle (ASM) phenotype plasticity, characterized by reversible switching between contractile and proliferative phenotypes, is considered to contribute to increased ASM mass and airway hyper-responsiveness in asthma. Further, increased expression of collagen I has been observed within the ASM bundle of asthmatics. Previously, we showed that exposure of intact bovine tracheal smooth muscle (BTSM) to collagen I induces a switch from a contractile to a hypocontractile, proliferative phenotype. However, the functional relevance of this finding for intact human ASM has not been established. EXPERIMENTAL APPROACH We investigated the effects of exposure of human tracheal smooth muscle (HTSM) strips to monomeric collagen I and PDGF on contractile responses to methacholine and KCl. Expression of contractile proteins sm-α-actin and sm-MHC was assessed by Western blot analysis. The proliferation of HTSM cells was assessed by cell counting, measuring mitochondrial activity (Alamarblue conversion) and [(3) H]-thymidine incorporation. Proliferation of intact tissue slices was assessed by [(3) H]-thymidine incorporation. KEY RESULTS Culturing HTSM strips in the presence of collagen I or PDGF for 4 days reduced maximal contractile responses to methacholine or KCl and the expression of contractile proteins. Conversely, collagen I and PDGF increased proliferation of HTSM cells and proliferative responses in tissue slices. PDGF additively increased the proliferation of HTSM cells cultured on collagen I; this additive effect was not observed on contractility, contractile protein expression or proliferation of intact tissue. CONCLUSION AND IMPLICATIONS These findings indicate that collagen I and PDGF induce a functionally hypocontractile, proliferative phenotype of human ASM, which may contribute to airway remodelling in asthma.
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Affiliation(s)
- Bart G J Dekkers
- Department of Molecular Pharmacology, University of Groningen, Groningen, the Netherlands.
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Dekkers BGJ, Pehlic A, Mariani R, Bos IST, Meurs H, Zaagsma J. Glucocorticosteroids and β₂-adrenoceptor agonists synergize to inhibit airway smooth muscle remodeling. J Pharmacol Exp Ther 2012; 342:780-7. [PMID: 22685341 DOI: 10.1124/jpet.112.195867] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Airway remodeling, including increased airway smooth muscle (ASM) mass and contractility, contributes to increased airway narrowing in asthma. Increased ASM mass may be caused by exposure to mitogens, including platelet-derived growth factor (PDGF) and collagen type I, which induce a proliferative, hypocontractile ASM phenotype. In contrast, prolonged exposure to insulin induces a hypercontractile phenotype. Glucocorticosteroids and β₂-adrenoceptor agonists synergize to increase glucocorticosteroid receptor translocation in ASM cells; however, the impact of this synergism on phenotype modulation is unknown. Using bovine tracheal smooth muscle, we investigated the effects of the glucocorticosteroids fluticasone (10 nM), budesonide (30 nM), and dexamethasone (0.1-1 μM) and the combination of low concentrations of fluticasone (3-100 pM) and fenoterol (10 nM) on ASM phenotype switching in response to PDGF (10 ng/ml), collagen type I (50 μg/ml), and insulin (1 μM). All glucocorticosteroids inhibited PDGF- and collagen I-induced proliferation and hypocontractility, with the effects of collagen I being less susceptible to glucocorticosteroid action. At 100-fold lower concentrations, fluticasone (100 pM) synergized with fenoterol to prevent PDGF- and collagen I-induced phenotype switching. This inhibition of ASM phenotype switching was associated with a normalization of the PDGF-induced decrease in the cell cycle inhibitors p21(WAF1/CIP1) and p57(KIP2). At this concentration, fluticasone also prevented the insulin-induced hypercontractile phenotype. At even lower concentrations, fluticasone (3 pM) synergized with fenoterol to inhibit this phenotype switch. Collectively, these findings indicate that glucocorticosteroids and β₂-agonists synergistically inhibit ASM phenotype switching, which may contribute to the increased effectiveness of combined treatment with glucocorticosteroids and β₂-agonists in asthma.
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Affiliation(s)
- Bart G J Dekkers
- Department of Molecular Pharmacology, University Centre for Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
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8
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Pasternyk SM, D'Antoni ML, Venkatesan N, Siddiqui S, Martin JG, Ludwig MS. Differential effects of extracellular matrix and mechanical strain on airway smooth muscle cells from ovalbumin- vs. saline-challenged Brown Norway rats. Respir Physiol Neurobiol 2012; 181:36-43. [PMID: 22310394 DOI: 10.1016/j.resp.2012.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 01/10/2012] [Accepted: 01/11/2012] [Indexed: 01/15/2023]
Abstract
The asthmatic airway is characterized by alterations in decorin and biglycan and increased airway smooth muscle (ASM). Further, the asthmatic airway may be subjected to abnormal mechanical strain. We hypothesized that ASM cells obtained from ovalbumin (OVA)--and saline (SAL)--challenged rats would respond differently to matrix and mechanical strain. ASMC were seeded on plastic, decorin or biglycan. Additional cells were grown on decorin, biglycan or collagen type 1, and then subjected to mechanical strain (Flexercell). The number of OVA ASMC was significantly greater than SAL ASM when seeded on plastic. A significant decrease was observed for both OVA and SAL ASMC seeded on decorin compared to plastic; the reduction in ASMC number was more modest for OVA. Biglycan decreased SAL ASMC number only. Strain reduced cell number for SAL and OVA ASMC grown on all matrices. Strain affected expression of β1-integrin differently in OVA vs. SAL ASMC. These data suggest that matrix and mechanical strain modulate ASMC number; these effects are differentially observed in OVA ASMC.
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Affiliation(s)
- Stephanie M Pasternyk
- Meakins-Christie Laboratories, McGill University Health Center, 3626 St. Urbain Street, Montreal, Quebec, Canada H2X 2P2
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9
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Abstract
Airway smooth muscle has classically been of interest for its contractile response linked to bronchoconstriction. However, terminally differentiated smooth muscle cells are phenotypically plastic and have multifunctional capacity for proliferation, cellular hypertrophy, migration, and the synthesis of extracellular matrix and inflammatory mediators. These latter properties of airway smooth muscle are important in airway remodeling which is a structural alteration that compounds the impact of contractile responses on limiting airway conductance. In this overview, we describe the important signaling components and the functional evidence supporting a view of smooth muscle cells at the core of fibroproliferative remodeling of hollow organs. Signal transduction components and events are summarized that control the basic cellular processes of proliferation, cell survival, apoptosis, and cellular migration. We delineate known intracellular control mechanisms and suggest future areas of interest to pursue to more fully understand factors that regulate normal myocyte function and airway remodeling in obstructive lung diseases.
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Affiliation(s)
- William T Gerthoffer
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA.
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10
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Slowed diffusion of single nanoparticles in the extracellular microenvironment of living cells revealed by darkfield microscopy. Anal Bioanal Chem 2010; 399:353-9. [DOI: 10.1007/s00216-010-4340-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2010] [Revised: 10/08/2010] [Accepted: 10/12/2010] [Indexed: 12/14/2022]
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11
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Dekkers BGJ, Bos IST, Gosens R, Halayko AJ, Zaagsma J, Meurs H. The integrin-blocking peptide RGDS inhibits airway smooth muscle remodeling in a guinea pig model of allergic asthma. Am J Respir Crit Care Med 2009; 181:556-65. [PMID: 20019343 DOI: 10.1164/rccm.200907-1065oc] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Airway remodeling, including increased airway smooth muscle (ASM) mass and contractility, contributes to airway hyperresponsiveness in asthma. The mechanisms driving these changes are, however, incompletely understood. Recently, an important role for extracellular matrix proteins in regulating ASM proliferation and contractility has been found, suggesting that matrix proteins and their integrins actively modulate airway remodeling. OBJECTIVES To investigate the role of RGD (Arg-Gly-Asp)-binding integrins in airway remodeling in an animal model of allergic asthma. METHODS Using a guinea pig model of allergic asthma, the effects of topical application of the integrin-blocking peptide RGDS (Arg-Gly-Asp-Ser) and its negative control GRADSP (Gly-Arg-Ala-Asp-Ser-Pro) were assessed on markers of ASM remodeling, fibrosis, and inflammation induced by repeated allergen challenge. In addition, effects of these peptides on human ASM proliferation and maturation were investigated in vitro. MEASUREMENTS AND MAIN RESULTS RGDS attenuated allergen-induced ASM hyperplasia and hypercontractility as well as increased pulmonary expression of smooth muscle myosin heavy chain and the proliferative marker proliferating cell nuclear antigen (PCNA). No effects were observed for GRADSP. The RGDS effects were ASM selective, as allergen-induced eosinophil and neutrophil infiltration as well as fibrosis were unaffected. In cultured human ASM cells, we demonstrated that proliferation induced by collagen I, fibronectin, serum, and platelet-derived growth factor requires signaling via RGD-binding integrins, particularly of the alpha(5)beta(1) subtype. In addition, RGDS inhibited smooth muscle alpha-actin accumulation in serum-deprived ASM cells. CONCLUSIONS This is the first study indicating that integrins modulate ASM remodeling in an animal model of allergic asthma, which can be inhibited by a small peptide containing the RGD motif.
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Affiliation(s)
- Bart G J Dekkers
- Department of Molecular Pharmacology, University of Groningen, The Netherlands.
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12
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Royce SG, Tan L, Koek AA, Tang MLK. Effect of extracellular matrix composition on airway epithelial cell and fibroblast structure: implications for airway remodeling in asthma. Ann Allergy Asthma Immunol 2009; 102:238-46. [PMID: 19354071 DOI: 10.1016/s1081-1206(10)60087-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Airway remodeling in asthma is characterized by structural changes to the airways including extracellular matrix (ECM) deposition and epithelial metaplasia. Extracellular matrix deposition in the subepithelial region may play an important role in modulation of epithelial cell and fibroblast structure and function because it lies in immediate contact with these cell types and exists within the functional epithelial mesenchymal trophic unit. OBJECTIVE To investigate the effect of aberrant ECM components on airway epithelial cells and fibroblasts and the relationship among subepithelial ECM deposition, other remodeling changes, and airway hyperresponsiveness. METHODS BEAS-2B human airway epithelial cells and WI-38 human airway fibroblast cells were cultured on various ECM protein substrates (Matrigel, representing normal basement membrane matrix, or aberrant matrix proteins collagen I, collagen III, and fibronectin). Airway remodeling changes were determined using morphometry in sections from a murine model of chronic allergic airway disease. Airway reactivity to methacholine was determined, and these parameters correlated. RESULTS Abnormal ECM substrates induced epithelial and fibroblast proliferation and altered the cell morphology of both human airway epithelial cells and fibroblasts when compared with normal basement membrane ECM. Subepithelial matrix deposition in the mouse correlated with epithelial thickness, but only weak correlations were noted among the other parameters. CONCLUSIONS We have demonstrated that ECM may affect the growth of airway epithelial cells and fibroblasts in vitro and may influence epithelial thickness in the mouse. These findings may have implications for understanding the pathogenesis of asthma and future therapeutic targeting of airway remodeling.
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Affiliation(s)
- Simon G Royce
- Department of Allergy and Immunology, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
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13
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Schuliga MJ, See I, Ong SC, Soon L, Camoretti-Mercado B, Harris T, Stewart AG. Fibrillar collagen clamps lung mesenchymal cells in a nonproliferative and noncontractile phenotype. Am J Respir Cell Mol Biol 2009; 41:731-41. [PMID: 19329552 DOI: 10.1165/rcmb.2008-0361oc] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Pulmonary fibrosis is characterized by phenotypic changes to mesenchymal cells and an increase in the deposition of fibrillar collagen (fCollagen). This study investigated the effect of type I fCollagen on the phenotypic plasticity of human parenchymal fibroblasts (PFbs) in vitro. Cell numbers were 45% lower when cultured on fCollagen as compared with culture on its degradation product, monomeric collagen (mCollagen). DNA profiles indicated that fCollagen is antiproliferative, rather than proapoptotic. fCollagen suppressed basic fibroblast growth factor-stimulated increases in the levels of cyclin E and CDK2 mRNA. fCollagen also suppressed transforming growth factor-beta (100 pM)-stimulated increases in the mRNA and protein levels of alpha-smooth muscle actin (alpha-SMA), a marker of the myofibroblast phenotype. However, in cells exposed to fCollagen, the levels of matrix metalloproteinase (MMP)-1 and -14 mRNA, as well as active MMP-2 protein, were increased by between two- and fivefold. The MMP inhibitors, ilomastat (10 microM) and doxycycline (30 microM), attenuated the dissolution of collagen fibrils by fibroblasts maintained on fCollagen, with a corresponding decrease in cell number. Ilomastat also reduced alpha-SMA expression and the capacity of PFb to contract three-dimensional fCollagen gels. Thus, exposure of fibroblasts to the fibrillar form of type I collagen in vitro reduces cell proliferation, increases MMP production and activation, and attenuates differentiation of PFb into myofibroblasts. fCollagen appears to apply a phenotypic clamp on lung fibroblasts that may be partially released by autocrine MMP activity.
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Affiliation(s)
- Michael J Schuliga
- Department of Pharmacology, University of Melbourne, Grattan Street, Parkville, Victoria 3010, Australia
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14
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Burgess JK, Ceresa C, Johnson SR, Kanabar V, Moir LM, Nguyen TTB, Oliver BGG, Schuliga M, Ward J. Tissue and matrix influences on airway smooth muscle function. Pulm Pharmacol Ther 2008; 22:379-87. [PMID: 19135163 DOI: 10.1016/j.pupt.2008.12.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Revised: 11/14/2008] [Accepted: 12/10/2008] [Indexed: 01/01/2023]
Abstract
Asthma is characterized by structural changes in the airways - airway remodelling. These changes include an increase in the bulk of the airway smooth muscle (ASM) and alterations in the profile of extracellular matrix (ECM) proteins in the airway wall. The mechanisms leading to airway remodelling are not well understood. ASM cells have the potential to play a key role in these processes through the production and release of ECM proteins. The ASM cells and ECM proteins are each able to influence the behaviour and characteristics of the other. The modified ECM profile in the asthmatic airway may contribute to the altered behaviour of the ASM cells, such responses to ECM proteins are modulated through the cell surface expression of integrin receptors. ASM cells from asthmatic individuals express different levels of some integrin subunits compared to nonasthmatic ASM cells, which have the potential to further influence their responses to the ECM proteins in the airways. ECM homeostasis requires the presence and activation of matrix metalloproteinases and their tissue inhibitors, which in turn modulate the interaction of the ASM cells and the ECM proteins. Furthermore, the complex interactions of the ASM cells and the ECM in the asthmatic airways and the role played by external stimuli, such as viral infections, to modulate airway remodelling are currently unknown. This review summarises our current understanding of the influence of the ECM on ASM function.
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Affiliation(s)
- Janette K Burgess
- Discipline of Pharmacology, Bosch Institute, University of Sydney, Sydney, Australia.
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15
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Siddiqui S, Martin JG. Structural aspects of airway remodeling in asthma. Curr Allergy Asthma Rep 2008; 8:540-7. [PMID: 18940147 DOI: 10.1007/s11882-008-0098-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Airway remodeling in asthma is a complex process that involves structural changes in virtually all tissues of the airway wall. The histologic changes to the airways consist of epithelial proliferation and goblet cell differentiation, subepithelial fibrosis, airway smooth muscle (ASM) growth, angiogenesis, matrix protein deposition, gland hyperplasia and hypertrophy, and nerve proliferation. Cytokines, chemokines, and growth factors from inflammatory cells and structural cells contribute to remodeling. There are complex interactions among the various signaling pathways involving matrix metalloproteinases that are required for growth factor release. The physiologic consequences of remodeling are airway hyperresponsiveness from ASM growth and mucus hypersecretion from gland and goblet cell hyperplasia. Airway stiffening is a probable contributor to airway hyperresponsiveness through attenuation of the transmission of potently bronchodilating cyclical stress to the ASM during breathing. The epidermal growth factor receptor's role in remodeling and its interaction with other potential causes of remodeling are discussed.
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Affiliation(s)
- Sana Siddiqui
- Meakins Christie Laboratories, McGill University, 3626 St. Urbain Street, Montreal, Quebec H2X 2P2, Canada
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16
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Fairbank NJ, Connolly SC, Mackinnon JD, Wehry K, Deng L, Maksym GN. Airway smooth muscle cell tone amplifies contractile function in the presence of chronic cyclic strain. Am J Physiol Lung Cell Mol Physiol 2008; 295:L479-88. [PMID: 18586955 DOI: 10.1152/ajplung.00421.2007] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic contractile activation, or tone, in asthma coupled with continuous stretching due to breathing may be involved in altering the contractile function of airway smooth muscle (ASM). Previously, we (11) showed that cytoskeletal remodeling and stiffening responses to acute (2 h) localized stresses were modulated by the level of contractile activation of ASM. Here, we investigated if altered contractility in response to chronic mechanical strain was dependent on repeated modulation of contractile tone. Cultured human ASM cells received 5% cyclic (0.3 Hz), predominantly uniaxial strain for 5 days, with once-daily dosing of either sham, forskolin, carbachol, or histamine to alter tone. Stiffness, contractility (KCl), and "relaxability" (forskolin) were then measured as was cell alignment, myosin light-chain phosphorylation (pMLC), and myosin light-chain kinase (MLCK) content. Cells became aligned and baseline stiffness increased with strain, but repeated lowering of tone inhibited both effects (P < 0.05). Strain also reversed a negative tone-modulation dependence of MLCK, observed in static conditions in agreement with previous reports, with strain and tone together increasing both MLCK and pMLC. Furthermore, contractility increased 176% (SE 59) with repeated tone elevation. These findings indicate that with strain, and not without, repeated tone elevation promoted contractile function through changes in cytoskeletal organization and increased contractile protein. The ability of repeated contractile activation to increase contractility, but only with mechanical stretching, suggests a novel mechanism for increased ASM contractility in asthma and for the role of continuous bronchodilator and corticosteroid therapy in reversing airway hyperresponsiveness.
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Affiliation(s)
- Nigel J Fairbank
- School of Biomedical Engineering, Dalhousie Univ., 5981 Univ. Ave., Halifax, Nova Scotia B3H 1W2, Canada
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17
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Pharmacology of airway smooth muscle proliferation. Eur J Pharmacol 2008; 585:385-97. [PMID: 18417114 DOI: 10.1016/j.ejphar.2008.01.055] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 01/11/2008] [Accepted: 01/24/2008] [Indexed: 02/03/2023]
Abstract
Airway smooth muscle thickening is a pathological feature that contributes significantly to airflow limitation and airway hyperresponsiveness in asthma. Ongoing research efforts aimed at identifying the mechanisms responsible for the increased airway smooth muscle mass have indicated that hyperplasia of airway smooth muscle, due in part to airway myocyte proliferation, is likely a major factor. Airway smooth muscle proliferation has been studied extensively in culture and in animal models of asthma, and these studies have revealed that a variety of receptors and mediators contributes to this response. This review aims to provide an overview of the receptors and mediators that control airway smooth muscle cell proliferation, with emphasis on the intracellular signalling mechanisms involved.
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18
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D'Antoni ML, Torregiani C, Ferraro P, Michoud MC, Mazer B, Martin JG, Ludwig MS. Effects of decorin and biglycan on human airway smooth muscle cell proliferation and apoptosis. Am J Physiol Lung Cell Mol Physiol 2008; 294:L764-71. [PMID: 18245265 DOI: 10.1152/ajplung.00436.2007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Proteoglycans (PG) are altered in the asthmatic airway wall. Because PGs are known to affect cell proliferation and apoptosis, we hypothesized that alterations in PG might influence the airway smooth muscle (ASM) hyperplasia observed in the asthmatic airway. Human ASM cells were seeded on plastic or plates coated with decorin (Dcn), biglycan (Bgn), or collagen type I (Col I) (1, 3, and 10 microg/ml). Cells were stimulated with platelet-derived growth factor (PDGF), and cell number was assessed at 0, 48, and 96 h. Cell proliferation was measured by bromodeoxyuridine (BrdU) incorporation and apoptosis by annexin V and propidium iodide staining at 48 h post-PDGF stimulation. A significant decrease in cell number was observed with cells seeded on Dcn (10 microg/ml) at 0, 48, and 96 h (P < 0.01). Dcn induced both decreases in BrdU incorporation and increases in annexin V staining (P < 0.05). Bgn decreased cell number at time 0 only (P < 0.05) and affected neither proliferation nor apoptosis. Col I (10 mug/ml) caused a significant increase in cell number at 48 and 96 h (P < 0.01). Adding exogenous Dcn (1-30 microg/ml) to the medium had no effect on cell number. Exposing Dcn-coated matrices to chondroitinase ABC, an enzyme that degrades glycosaminoglycan side chains, reversed the Dcn-induced decrease in cell number. These studies demonstrate that different PGs have variable effects on ASM cell proliferation and apoptosis. Recently described decreases in Dcn in the asthmatic airway wall could potentially permit more exuberant ASM growth.
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An S, Bai T, Bates J, Black J, Brown R, Brusasco V, Chitano P, Deng L, Dowell M, Eidelman D, Fabry B, Fairbank N, Ford L, Fredberg J, Gerthoffer W, Gilbert S, Gosens R, Gunst S, Halayko A, Ingram R, Irvin C, James A, Janssen L, King G, Knight D, Lauzon A, Lakser O, Ludwig M, Lutchen K, Maksym G, Martin J, Mauad T, McParland B, Mijailovich S, Mitchell H, Mitchell R, Mitzner W, Murphy T, Paré P, Pellegrino R, Sanderson M, Schellenberg R, Seow C, Silveira P, Smith P, Solway J, Stephens N, Sterk P, Stewart A, Tang D, Tepper R, Tran T, Wang L. Airway smooth muscle dynamics: a common pathway of airway obstruction in asthma. Eur Respir J 2007; 29:834-60. [PMID: 17470619 PMCID: PMC2527453 DOI: 10.1183/09031936.00112606] [Citation(s) in RCA: 279] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Excessive airway obstruction is the cause of symptoms and abnormal lung function in asthma. As airway smooth muscle (ASM) is the effecter controlling airway calibre, it is suspected that dysfunction of ASM contributes to the pathophysiology of asthma. However, the precise role of ASM in the series of events leading to asthmatic symptoms is not clear. It is not certain whether, in asthma, there is a change in the intrinsic properties of ASM, a change in the structure and mechanical properties of the noncontractile components of the airway wall, or a change in the interdependence of the airway wall with the surrounding lung parenchyma. All these potential changes could result from acute or chronic airway inflammation and associated tissue repair and remodelling. Anti-inflammatory therapy, however, does not "cure" asthma, and airway hyperresponsiveness can persist in asthmatics, even in the absence of airway inflammation. This is perhaps because the therapy does not directly address a fundamental abnormality of asthma, that of exaggerated airway narrowing due to excessive shortening of ASM. In the present study, a central role for airway smooth muscle in the pathogenesis of airway hyperresponsiveness in asthma is explored.
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Affiliation(s)
- S.S. An
- Division of Physiology, Dept of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health
| | - T.R. Bai
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - J.H.T. Bates
- Vermont Lung Center, University of Vermont College of Medicine, Burlington, VT
| | - J.L. Black
- Dept of Pharmacology, University of Sydney, Sydney
| | - R.H. Brown
- Dept of Anesthesiology and Critical Care medicine, Johns Hopkins Medical Institutions, Baltimore, MD
| | - V. Brusasco
- Dept of Internal Medicine, University of Genoa, Genoa
| | - P. Chitano
- Dept of Paediatrics, Duke University Medical Center, Durham, NC
| | - L. Deng
- Program in Molecular and Integrative Physiological Sciences, Dept of Environmental Health, Harvard School of Public Health
- Bioengineering College, Chongqing University, Chongqing, China
| | - M. Dowell
- Section of Pulmonary and Critical Care Medicine
| | - D.H. Eidelman
- Meakins-Christie Laboratories, Dept of Medicine, McGill University, Montreal
| | - B. Fabry
- Center for Medical Physics and Technology, Erlangen, Germany
| | - N.J. Fairbank
- School of Biomedical Engineering, Dalhousie University, Halifax
| | | | - J.J. Fredberg
- Program in Molecular and Integrative Physiological Sciences, Dept of Environmental Health, Harvard School of Public Health
| | - W.T. Gerthoffer
- Dept of Pharmacology, University of Nevada School of Medicine, Reno, NV
| | | | - R. Gosens
- Dept of Physiology, University of Manitoba, Winnipeg
| | - S.J. Gunst
- Dept of Physiology, Indiana University School of Medicine, Indianapolis, IN
| | - A.J. Halayko
- Dept of Physiology, University of Manitoba, Winnipeg
| | - R.H. Ingram
- Dept of Medicine, Emory University School of Medicine, Atlanta, GA
| | - C.G. Irvin
- Vermont Lung Center, University of Vermont College of Medicine, Burlington, VT
| | - A.L. James
- West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands
| | - L.J. Janssen
- Dept of Medicine, McMaster University, Hamilton, Canada
| | - G.G. King
- Woolcock Institute of Medical Research, Camperdown
| | - D.A. Knight
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - A.M. Lauzon
- Meakins-Christie Laboratories, Dept of Medicine, McGill University, Montreal
| | - O.J. Lakser
- Section of Paediatric Pulmonary Medicine, University of Chicago, Chicago, IL
| | - M.S. Ludwig
- Meakins-Christie Laboratories, Dept of Medicine, McGill University, Montreal
| | - K.R. Lutchen
- Dept of Biomedical Engineering, Boston University, Boston
| | - G.N. Maksym
- School of Biomedical Engineering, Dalhousie University, Halifax
| | - J.G. Martin
- Meakins-Christie Laboratories, Dept of Medicine, McGill University, Montreal
| | - T. Mauad
- Dept of Pathology, Sao Paulo University Medical School, Sao Paulo, Brazil
| | | | - S.M. Mijailovich
- Program in Molecular and Integrative Physiological Sciences, Dept of Environmental Health, Harvard School of Public Health
| | - H.W. Mitchell
- Discipline of Physiology, School of Biomedical, Biomolecular and Chemical Sciences, University of Western Australia, Perth
| | | | - W. Mitzner
- Division of Physiology, Dept of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health
| | - T.M. Murphy
- Dept of Paediatrics, Duke University Medical Center, Durham, NC
| | - P.D. Paré
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - R. Pellegrino
- Dept of Respiratory Physiopathology, S. Croce e Carle Hospital, Cuneo, Italy
| | - M.J. Sanderson
- Dept of Physiology, University of Massachusetts Medical School, Worcester, MA
| | - R.R. Schellenberg
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - C.Y. Seow
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - P.S.P. Silveira
- Dept of Pathology, Sao Paulo University Medical School, Sao Paulo, Brazil
| | - P.G. Smith
- Dept of Paediatrics, School of Medicine, Case Western Reserve University, Cleveland, OH
| | - J. Solway
- Section of Pulmonary and Critical Care Medicine
| | - N.L. Stephens
- Dept of Physiology, University of Manitoba, Winnipeg
| | - P.J. Sterk
- Dept of Pulmonology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - A.G. Stewart
- Dept of Pharmacology, University of Melbourne, Parkville, Australia
| | - D.D. Tang
- Center for Cardiovascular Sciences, Albany Medical College, Albany, NY, USA
| | - R.S. Tepper
- Dept of Paediatrics, Indiana University School of Medicine, Indianapolis, IN
| | - T. Tran
- Dept of Physiology, University of Manitoba, Winnipeg
| | - L. Wang
- Dept of Paediatrics, Duke University Medical Center, Durham, NC
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20
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Dekkers BGJ, Schaafsma D, Nelemans SA, Zaagsma J, Meurs H. Extracellular matrix proteins differentially regulate airway smooth muscle phenotype and function. Am J Physiol Lung Cell Mol Physiol 2007; 292:L1405-13. [PMID: 17293376 DOI: 10.1152/ajplung.00331.2006] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Changes in the ECM and increased airway smooth muscle (ASM) mass are major contributors to airway remodeling in asthma and chronic obstructive pulmonary disease. It has recently been demonstrated that ECM proteins may differentially affect proliferation and expression of phenotypic markers of cultured ASM cells. In the present study, we investigated the functional relevance of ECM proteins in the modulation of ASM contractility using bovine tracheal smooth muscle (BTSM) preparations. The results demonstrate that culturing of BSTM strips for 4 days in the presence of fibronectin or collagen I depressed maximal contraction (E(max)) both for methacholine and KCl, which was associated with decreased contractile protein expression. By contrast, both fibronectin and collagen I increased proliferation of cultured BTSM cells. Similar effects were observed for PDGF. Moreover, PDGF augmented fibronectin- and collagen I-induced proliferation in an additive fashion, without an additional effect on contractility or contractile protein expression. The fibronectin-induced depression of contractility was blocked by the integrin antagonist Arg-Gly-Asp-Ser (RGDS) but not by its negative control Gly-Arg-Ala-Asp-Ser-Pro (GRADSP). Laminin, by itself, did not affect contractility or proliferation but reduced the effects of PDGF on these parameters. Strong relationships were found between the ECM-induced changes in E(max) in BTSM strips and their proliferative responses in BSTM cells and for E(max) and contractile protein expression. Our results indicate that ECM proteins differentially regulate both phenotype and function of intact ASM.
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Affiliation(s)
- Bart G J Dekkers
- Department of Molecular Pharmacology, University Centre for Pharmacy, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands.
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21
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Ammit AJ, Moir LM, Oliver BG, Hughes JM, Alkhouri H, Ge Q, Burgess JK, Black JL, Roth M. Effect of IL-6 trans-signaling on the pro-remodeling phenotype of airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2006; 292:L199-206. [PMID: 16936245 DOI: 10.1152/ajplung.00230.2006] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Increased levels of IL-6 are documented in asthma, but its contribution to the pathology is unknown. Asthma is characterized by airway wall thickening due to increased extracellular matrix deposition, inflammation, angiogenesis, and airway smooth muscle (ASM) mass. IL-6 binds to a specific membrane-bound receptor, IL-6 receptor-alpha (mIL-6Ralpha), and subsequently to the signaling protein gp130. Alternatively, IL-6 can bind to soluble IL-6 recpetor-alpha (sIL-6Ralpha) to stimulate membrane receptor-deficient cells, a process called trans-signaling. We discovered that primary human ASM cells do not express mIL-6Ralpha and, therefore, investigated the effect of IL-6 trans-signaling on the pro-remodeling phenotype of ASM. ASM required sIL-6Ralpha to activate signal transducer and activator 3, with no differences observed between cells from asthmatic subjects compared with controls. Further analysis revealed that IL-6 alone or with sIL-6Ralpha did not induce release of matrix-stimulating factors (including connective tissue growth factor, fibronectin, or integrins) and had no effect on mast cell adhesion to ASM or ASM proliferation. However, in the presence of sIL-6Ralpha, IL-6 increased eotaxin and VEGF release and may thereby contribute to local inflammation and vessel expansion in airway walls of asthmatic subjects. As levels of sIL-6Ralpha are increased in asthma, this demonstration of IL-6 trans-signaling in ASM has relevance to the development of airway remodeling.
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Affiliation(s)
- Alaina J Ammit
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia.
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Holgate ST, Holloway J, Wilson S, Howarth PH, Haitchi HM, Babu S, Davies DE. Understanding the pathophysiology of severe asthma to generate new therapeutic opportunities. J Allergy Clin Immunol 2006; 117:496-506; quiz 507. [PMID: 16522446 DOI: 10.1016/j.jaci.2006.01.039] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Revised: 01/30/2006] [Accepted: 01/30/2006] [Indexed: 11/27/2022]
Abstract
Although asthma is defined in terms of reversibility of airflow obstruction, as the disease becomes more severe and chronic, it adopts different characteristics, including a degree of fixed airflow obstruction and corticosteroid refractoriness. Underlying these phenotypes is evidence of airway wall remodeling, which should be distinguished from the increase in smooth muscle linked to airways hyperresponsiveness. Aberrant epithelial-mesenchymal communication leads to a chronic wound scenario, which is characterized by activation of the epithelial-mesenchymal trophic unit, epithelial damage, the laying down of new matrix, and greater involvement of neutrophils in the inflammatory response. In allergic asthmatic patients who remain symptomatic despite high-dose corticosteroid therapy, blockade of IgE with omalizumab confers appreciable clinical benefit. Chronic severe asthma is also accompanied by a marked increase in TNF-alpha production that might contribute to corticosteroid refractoriness. Based on this, TNF blockade with the soluble fusion protein entanercept produces improvement in asthma symptoms, lung function, and quality of life paralleled by a marked reduction in airways hyperresponsiveness. Identification of novel susceptibility genes, such as a disintegrin and metalloprotease 33 (ADAM33), will provide further targets against which to direct novel therapies for asthma, especially at the more severe end of the disease spectrum.
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Affiliation(s)
- Stephen T Holgate
- Division of Infection, Inflammation and Repair, School of Medicine, University of Southampton, Southampton General Hospital, UK.
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Tang MLK, Wilson JW, Stewart AG, Royce SG. Airway remodelling in asthma: current understanding and implications for future therapies. Pharmacol Ther 2006; 112:474-88. [PMID: 16759709 DOI: 10.1016/j.pharmthera.2006.05.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 05/01/2006] [Indexed: 02/08/2023]
Abstract
Airway remodelling refers to the structural changes that occur in the airway wall in asthma. These include epithelial hyperplasia and metaplasia, subepithelial fibrosis, muscle cell hyperplasia and angiogenesis. These structural changes result in thickening of the airway wall, airway hyperresponsiveness (AHR), and a progressive irreversible loss of lung function. The precise sequence of events that take place during the remodelling process and the mechanisms regulating these changes remain poorly understood. It is thought that airway remodelling is initiated and promoted by repeated episodes of allergic inflammation that damage the surface epithelium of the airway. However, other mechanisms are also likely to contribute to this process. Moreover, the interrelationship between airway remodelling, inflammation and AHR has not been clearly defined. Currently, there are no effective treatments that halt or reverse the changes of airway remodelling and its effects on lung function. Glucocorticoids have been unable to eliminate the progression of remodelling changes and there is limited evidence of a beneficial effect from other available therapies. The search for novel therapies that can directly target individual components of the remodelling process should be made a priority. In this review, we describe the current understanding of the airway remodelling process and the mechanisms regulating its development. The impact of currently available asthma therapies on airway remodelling is also discussed.
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Affiliation(s)
- Mimi L K Tang
- Department of Immunology, Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne 3052, Australia.
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Chan V, Burgess JK, Ratoff JC, O'connor BJ, Greenough A, Lee TH, Hirst SJ. Extracellular matrix regulates enhanced eotaxin expression in asthmatic airway smooth muscle cells. Am J Respir Crit Care Med 2006; 174:379-85. [PMID: 16709936 DOI: 10.1164/rccm.200509-1420oc] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Altered airway smooth muscle (ASM) function and enrichment of the extracellular matrix (ECM) with fibronectin and collagen are key features of asthma. Previously, we have reported these ECM proteins enhance ASM synthetic function. OBJECTIVE We compared ASM cultured from endobronchial biopsies from subjects with and without asthma to assess if asthmatic cells were hypersecretory and determined whether the underlying mechanism involved autocrine ECM production. METHODS AND MEASUREMENTS Cells from subjects with and without asthma were cultured on plastic or in plates precoated with ECM proteins. Cytokine production was evaluated by enzyme-linked immunosorbent assay and by reverse transcriptase-polymerase chain reaction. Function-blocking integrin antibodies were used to identify integrin involvement. RESULTS Baseline eotaxin and its production after stimulation with interleukin (IL)-13, IL-1beta, or tumor necrosis factor-alpha was increased (2.5- to 6.0-fold) in ASM cells cultured from subjects with asthma compared with healthy subjects. When seeded on ECM from asthmatic ASM, IL-13-dependent eotaxin release from healthy or asthmatic ASM was enhanced compared with culture on healthy ECM. The ECM substrates fibronectin and type I collagen each enhanced IL-13-dependent eotaxin release, and Western immunoblot indicated that fibronectin expression was higher in asthmatic ASM cells. Integrin-blocking antibodies revealed that alpha5beta1 was required for more than 50% of the enhanced IL-13-dependent eotaxin release by ASM cells from subjects with asthma, whereas alpha2beta1 or alphavbeta3 neutralization lacked effect. CONCLUSION The data indicate that ASM cells cultured from subjects with asthma are hypersecretory compared with cells from healthy donors and that autocrine fibronectin secretion acting via alpha5beta1 in part underlies this effect.
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Affiliation(s)
- Vivien Chan
- King's College London School of Medicine, MRC and Asthma UK Centre in Allergic Mechanisms of Asthma, Thomas Guy House, Guy's Hospital Campus, London SE1 9RT, UK
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25
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Affiliation(s)
- Kwan Hyoung Kim
- Department of Internal Medicine The Catholic University of Korea College of Medicine, Korea
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Shepherd MC. Phosphodiesterase 4 regulation of cyclic AMP in pulmonary remodelling: potential roles for isoform selective inhibitors. Pulm Pharmacol Ther 2005; 19:24-31. [PMID: 16046159 DOI: 10.1016/j.pupt.2005.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Accepted: 05/21/2005] [Indexed: 11/21/2022]
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Bonacci JV, Stewart AG. Regulation of human airway mesenchymal cell proliferation by glucocorticoids and beta2-adrenoceptor agonists. Pulm Pharmacol Ther 2005; 19:32-8. [PMID: 16286235 DOI: 10.1016/j.pupt.2005.02.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2005] [Revised: 02/14/2005] [Accepted: 02/22/2005] [Indexed: 01/06/2023]
Abstract
Altered rates of cell proliferation play important roles in the pathogenesis of a variety of conditions, including cancer, inflammation and several airway and cardiovascular diseases. One of the most consistently observed changes in asthmatic airways is an increased volume of airway smooth muscle (ASM), that has been explained by proliferation, hypertrophy, extracellular matrix deposition within the smooth muscle bundles, and more recently, the migration of mesenchymal precursor cells to the airways. The best characterised of these is proliferation of ASM cells. In vitro studies suggest that the proliferation is driven by various mitogens, and ECM proteins found in asthma, such as collagen type I. Therefore, we compared the anti-mitogenic actions of two classes of anti-asthma agents, the glucocorticoids and the beta2-adrenoceptor agonists, in ASM cells grown on collagen type I. Culture on collagen type I prevented the anti-mitogenic actions of glucocorticoids, but not beta2-adrenoceptor agonists. In contrast, glucocorticoids are efficacious in regulating ASM production of GM-CSF, whereas beta2-adrenoceptor agonists are without effect. Therefore, combination therapy may have increased efficacy over glucocorticoids alone in controlling remodelling events due to complementary actions of the two classes of compounds.
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Affiliation(s)
- John V Bonacci
- Department of Pharmacology, The University of Melbourne, Vic. 3010, Australia
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Abstract
PURPOSE OF REVIEW This overview summarizes some the more recent studies of remodeling in patients with asthma, studies using animal models to study the interaction of cell types and mediators, and studies using in vitro models to assess the effects of mitogenic stimuli, including mechanical strain, on mesenchymal cells and extracellular matrix proteins. The aim is to demonstrate how the term remodeling is becoming increasingly less specific as reductionism is applied to this field of study. RECENT FINDINGS Specific areas of recent interest include plasticity of airway smooth muscle and fibroblast phenotype; the role of the extracellular matrix and its relation to the function of the airway smooth muscle and the mechanical properties of the airway wall; mitogenic stimuli arising from damaged epithelium, fibroblasts, smooth muscle cells, mast cells, eosinophils, and mechanical stress; extracellular and intracellular signaling in fibroblasts and smooth muscle cells; and therapeutic targets among the many pathways of remodeling-pathways that may be distinct from those involved in inflammation. The potential functional consequences of some of these findings call into question the role of remodeling. In some respects, it may represent a continuum from inflammation to scarring, but it may also be a protective response to altered airway mechanics caused by ongoing tissue damage or by abnormal airway structure present from early in life. SUMMARY The diverse areas of research in this field are increasingly making the term remodeling as useful (or not) as the word asthma, because both can be used to describe simultaneously a large number of processes that may or may not be related to each other.
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Affiliation(s)
- Alan James
- West Australian Sleep Disorders Research Institute, Queen Elizabeth II Medical Centre, School of Medicine and Pharmacology, University of Western Australia, Perth, Australia.
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Peng Q, Lai D, Nguyen TTB, Chan V, Matsuda T, Hirst SJ. Multiple beta 1 integrins mediate enhancement of human airway smooth muscle cytokine secretion by fibronectin and type I collagen. THE JOURNAL OF IMMUNOLOGY 2005; 174:2258-64. [PMID: 15699160 DOI: 10.4049/jimmunol.174.4.2258] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Altered airway smooth muscle (ASM) function and enrichment of the extracellular matrix (ECM) with interstitial collagen and fibronectin are major pathological features of airway remodeling in asthma. We have previously shown that these ECM components confer enhanced ASM proliferation in vitro, but their action on its newly characterized secretory function is unknown. Here, we examined the effects of fibronectin and collagen types I, III, and V on IL-1beta-dependent secretory responses of human ASM cells, and characterized the involvement of specific integrins. Cytokine production (eotaxin, RANTES, and GM-CSF) was evaluated by ELISA, RT-PCR, and flow cytometry. Function-blocking integrin mAbs and RGD (Arg-Gly-Asp)-blocking peptides were used to identify integrin involvement. IL-1beta-dependent release of eotaxin, RANTES, and GM-CSF was enhanced by fibronectin and by fibrillar and monomeric type I collagen, with similar changes in mRNA abundance. Collagen types III and V had no effect on eotaxin or RANTES release but did modulate GM-CSF. Analogous changes in intracellular cytokine accumulation were found, but in <25% of the total ASM cell population. Function-blocking Ab and RGD peptide studies revealed that alpha2beta1, alpha5beta1, alphavbeta1, and alphavbeta3 integrins were required for up-regulation of IL-1beta-dependent ASM secretory responses by fibronectin, while alpha2beta1 was an important transducer for type I collagen. Thus, fibronectin and type I collagen enhance IL-1beta-dependent ASM secretory responses through a beta1 integrin-dependent mechanism. Enhancement of cytokine release from ASM by these ECM components may contribute to airway wall inflammation and remodeling in asthma.
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Affiliation(s)
- Qi Peng
- Department of Asthma, Allergy and Respiratory Science, The Guy's, King's and St. Thomas' School of Medicine, King's College London, Guy's Hospital Campus, London, United Kingdom
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de Jong-Hesse Y, Kampmeier J, Lang GK, Lang GE. Effect of extracellular matrix on proliferation and differentiation of porcine lens epithelial cells. Graefes Arch Clin Exp Ophthalmol 2005; 243:695-700. [PMID: 15702326 DOI: 10.1007/s00417-004-1116-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2004] [Revised: 12/01/2004] [Accepted: 12/08/2004] [Indexed: 10/25/2022] Open
Abstract
BACKGROUND Proliferation and differentiation of lens epithelial cells (LECs) are important mechanisms of secondary cataract formation. After extracapsular cataract extraction the extracellular matrix (ECM) around the remaining LECs is altered compared with the intact lens. This study investigated the effects of different ECMs on cell proliferation and alpha-smooth muscle actin (alpha-SMA) expression, a marker for myofibroblasts, in cultured porcine LECs. METHODS Porcine LECs were cultured for 3 days (cell proliferation assay) or 4 days (alpha-SMA expression) on wells and glass cover slips, respectively, coated with laminin, fibronectin, type I collagen or type IV collagen. LECs cultured on uncoated wells or cover slips served as control. Proliferative response was measured by [(3)H]-thymidine incorporation into DNA. alpha-SMA was detected immunocytochemically with a mouse monoclonal antibody, and the relative numbers of alpha-SMA-positive cells were calculated. Statistical analysis was performed using Student's unpaired t-test. RESULTS Cell proliferation was significantly increased by coating with fibronectin (10,320.5+/-6,073 counts per minute; p<0.0001) (mean +/- SD), type I collagen (12,507.3+/-3,914.2 CPM; p<0.0001) and type IV collagen (9,591.4+/-4,088 CPM; p<0.0001) compared with control (1,876.5+/-998 CPM), whereas coating with laminin had no effect (1,760.8+/-812.6 CPM; p=0.7271). The ratio of alpha-SMA-positive LECs cultured on uncoated cover slips for a period of 4 days was 12.2+/-3.51%. This ratio was significantly increased by coating with fibronectin (24.3+/-4.56%; p=0.0001) and type I collagen (21.2+/-8.48%; p=0.0142). Coating with laminin (9.8+/-3.67%; p=0.1682) and type IV collagen (9.0+/-7.09 %; p=0.2491) slightly decreased alpha-SMA expression, but this effect was not statistically significant. CONCLUSIONS Fibronectin and type I collagen stimulated both cell proliferation and alpha-SMA expression in cultured porcine LECs. Because fibronectin and type I collagen are not normally present in the adult lens, their possible introduction into the lens capsule after cataract surgery may play a critical role in the development of posterior capsule opacification.
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Affiliation(s)
- Yvonne de Jong-Hesse
- Department of Ophthalmology, University of Ulm, Prittwitzstrasse 43, 89075 Ulm, Germany
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Nguyen TTB, Ward JPT, Hirst SJ. beta1-Integrins mediate enhancement of airway smooth muscle proliferation by collagen and fibronectin. Am J Respir Crit Care Med 2004; 171:217-23. [PMID: 15502110 DOI: 10.1164/rccm.200408-1046oc] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Airway smooth muscle (ASM) accumulation and enrichment of the extracellular matrix (ECM) with type I collagen and fibronectin are major pathologic features of airway remodeling in asthma. These ECM components confer enhanced ASM proliferation in vitro, but a requirement for specific integrin ECM receptors has not been examined. Here, we examined the mitogen platelet-derived growth factor (PDGF)-BB on beta1-integrin expression on human ASM cells cultured on these ECM substrates and defined the involvement of specific integrins in cell attachment and proliferation using integrin-neutralizing antibodies. PDGF-BB-dependent proliferation was enhanced two- to threefold by monomeric type I collagen or fibronectin and to a lesser extent by vitronectin; other interstitial ECM components (fibrillar type I and III collagen and tenascin-C) had no effect. Except for increased alpha3 expression induced by PDGF-BB and monomeric type I collagen or fibronectin, alpha1, alpha2, alpha4, alpha5, alphav, and alphavbeta3 integrins were unchanged compared with unstimulated cells on plastic. Blocking antibodies revealed alpha2beta1- and alphavbeta3-mediated attachment to monomeric type I collagen, whereas attachment to fibronectin required alpha5beta1. In contrast, enhancement of PDGF-BB-dependent proliferation by either monomeric type I collagen or fibronectin required alpha2beta1, alpha4beta1, and alpha5beta1 integrins. These data suggest multiple beta1-integrins regulate enhanced ASM proliferative responses.
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Affiliation(s)
- Trang T-B Nguyen
- Department of Asthma, Allergy & Respiratory Science, The Guy's, King's, and St. Thomas' School of Medicine, Thomas Guy House, Guy's Hospital Campus, London SE1 9RT, UK
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Howarth PH, Knox AJ, Amrani Y, Tliba O, Panettieri RA, Johnson M. Synthetic responses in airway smooth muscle. J Allergy Clin Immunol 2004; 114:S32-50. [PMID: 15309017 DOI: 10.1016/j.jaci.2004.04.041] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Human airway smooth muscle (ASM) has several properties and functions that contribute to asthma pathogenesis, and increasing attention is being paid to its synthetic capabilities. ASM can promote the formation of the interstitial extracellular matrix, and in this respect, ASM from asthmatic subjects compared with normal subjects responds differently, both qualitatively and quantitatively. Thus, ASM cells are important regulating cells that potentially contribute to the known alterations within the extracellular matrix in asthma. In addition, through integrin-directed signaling, extracellular matrix components can alter the proliferative, survival, and cytoskeletal synthetic function of ASM cells. ASM also functions as a rich source of biologically active chemokines and cytokines that are capable of perpetuating airway inflammation in asthma and chronic obstructive pulmonary disease by promoting recruitment, activation, and trafficking of inflammatory cells in the airway milieu. Emerging evidence shows that airway remodeling may also be a result of the autocrine action of secreted inflammatory mediators, including T(H)2 cytokines, growth factors, and COX-2-dependent prostanoids. Finally, ASM cells contain both beta(2)-adrenergic receptors and glucocorticoid receptors and may represent a key target for beta(2)-adrenergic receptor agonist/corticosteroid interactions. Combinations of long-acting beta(2)-agonists and corticosteroids appear to have additive and/or synergistic effects in inhibiting inflammatory mediator release and the migration and proliferation of ASM cells.
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Affiliation(s)
- Peter H Howarth
- Respiratory Cell and Molecular Biology, Southampton General Hospital, Southampton, United Kingdom.
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Hirst SJ, Martin JG, Bonacci JV, Chan V, Fixman ED, Hamid QA, Herszberg B, Lavoie JP, McVicker CG, Moir LM, Nguyen TTB, Peng Q, Ramos-Barbón D, Stewart AG. Proliferative aspects of airway smooth muscle. J Allergy Clin Immunol 2004; 114:S2-17. [PMID: 15309015 DOI: 10.1016/j.jaci.2004.04.039] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Increased airway smooth muscle (ASM) mass is perhaps the most important component of the airway wall remodeling process in asthma. Known mediators of ASM proliferation in cell culture models fall into 2 categories: those that activate receptors with intrinsic receptor tyrosine kinase activity and those that have their effects through receptors linked to heterotrimeric guanosine triphosphate-binding proteins. The major candidate signaling pathways activated by ASM mitogens are those dependent on extracellular signal-regulated kinase and phosphoinositide 3'-kinase. Increases in ASM mass may also involve ASM migration, and in culture, the key signaling mechanisms have been identified as the p38 mitogen-activated protein kinase and the p21-activated kinase 1 pathways. New evidence from an in vivo rat model indicates that primed CD4(+) T cells are sufficient to trigger ASM and epithelial remodeling after allergen challenge. Hyperplasia has been observed in an equine model of asthma and may account for the increase in ASM mass. Reduction in the rate of apoptosis may also play a role. beta(2)-Adrenergic receptor agonists and glucocorticoids have antiproliferative activity against a broad spectrum of mitogens, although it has become apparent that mitogens are differentially sensitive. Culture of ASM on collagen type I has been shown to enhance proliferative activity and prevent the inhibitory effect of glucocorticoids, whereas beta(2)-agonists are minimally affected. There is no evidence that long-acting beta(2)-agonists are more effective than short-acting agonists, but persistent stimulation of the beta(2)-adrenergic receptor probably helps suppress growth responses. The maximum response of fluticasone propionate against thrombin-induced proliferation is increased when it is combined with salmeterol.
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Affiliation(s)
- Stuart J Hirst
- Department of Asthma, Allergy and Respiratory Science, Guy's, King's and St. Thomas' School of Medicine, Guy's Hospital Campus, King's College London, United Kingdom.
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