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Calzetta L, Page C, Matera MG, Cazzola M, Rogliani P. Use of human airway smooth muscle in vitro and ex vivo to investigate drugs for the treatment of chronic obstructive respiratory disorders. Br J Pharmacol 2024; 181:610-639. [PMID: 37859567 DOI: 10.1111/bph.16272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 10/21/2023] Open
Abstract
Isolated airway smooth muscle has been extensively investigated since 1840 to understand the pharmacology of airway diseases. There has often been poor predictability from murine experiments to drugs evaluated in patients with asthma or chronic obstructive pulmonary disease (COPD). However, the use of isolated human airways represents a sensible strategy to optimise the development of innovative molecules for the treatment of respiratory diseases. This review aims to provide updated evidence on the current uses of isolated human airways in validated in vitro methods to investigate drugs in development for the treatment of chronic obstructive respiratory disorders. This review also provides historical notes on the pioneering pharmacological research on isolated human airway tissues, the key differences between human and animal airways, as well as the pivotal differences between human medium bronchi and small airways. Experiments carried out with isolated human bronchial tissues in vitro and ex vivo replicate many of the main anatomical, pathophysiological, mechanical and immunological characteristics of patients with asthma or COPD. In vitro models of asthma and COPD using isolated human airways can provide information that is directly translatable into humans with obstructive lung diseases. Regardless of the technique used to investigate drugs for the treatment of chronic obstructive respiratory disorders (i.e., isolated organ bath systems, videomicroscopy and wire myography), the most limiting factors to produce high-quality and repeatable data remain closely tied to the manual skills of the researcher conducting experiments and the availability of suitable tissue.
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Affiliation(s)
- Luigino Calzetta
- Department of Medicine and Surgery, Respiratory Disease and Lung Function Unit, University of Parma, Parma, Italy
| | - Clive Page
- Pulmonary Pharmacology Unit, Institute of Pharmaceutical Science, King's College London, London, UK
| | - Maria Gabriella Matera
- Unit of Pharmacology, Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Mario Cazzola
- Unit of Respiratory Medicine, Department of Experimental Medicine, University of Rome "Tor Vergata", Rome, Italy
| | - Paola Rogliani
- Unit of Respiratory Medicine, Department of Experimental Medicine, University of Rome "Tor Vergata", Rome, Italy
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Huang AS, Tong BCK, Hung HCH, Wu AJ, Ho OKY, Kong AHY, Leung MMK, Bai J, Fu X, Yu Z, Li M, Leung TF, Mak JCW, Leung GPH, Cheung KH. Targeting calcium signaling by inositol trisphosphate receptors: A novel mechanism for the anti-asthmatic effects of Houttuynia cordata. Biomed Pharmacother 2023; 164:114935. [PMID: 37245337 DOI: 10.1016/j.biopha.2023.114935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/09/2023] [Accepted: 05/22/2023] [Indexed: 05/30/2023] Open
Abstract
Asthma is a chronic inflammatory disease characterized by airway hypersensitivity and remodeling. The current treatments provide only short-term benefits and may have undesirable side effects; thus, alternative or supplementary therapy is needed. Because intracellular calcium (Ca2+) signaling plays an essential role in regulating the contractility and remodeling of airway smooth muscle cells, the targeting of Ca2+ signaling is a potential therapeutic strategy for asthma. Houttuynia cordata is a traditional Chinese herb that is used to treat asthma due to its anti-allergic and anti-inflammatory properties. We hypothesized that H. cordata might modulate intracellular Ca2+ signaling and could help relieve asthmatic airway remodeling. We found that the mRNA and protein levels of inositol trisphosphate receptors (IP3Rs) were elevated in interleukin-stimulated primary human bronchial smooth muscle cells and a house dust mite-sensitized model of asthma. The upregulation of IP3R expression enhanced intracellular Ca2+ release upon stimulation and contributed to airway remodeling in asthma. Intriguingly, pretreatment with H. cordata essential oil rectified the disruption of Ca2+ signaling, mitigated asthma development, and prevented airway narrowing. Furthermore, our analysis suggested that houttuynin/2-undecanone could be the bioactive component in H. cordata essential oil because we found similar IP3R suppression in response to the commercially available derivative sodium houttuyfonate. An in silico analysis showed that houttuynin, which downregulates IP3R expression, binds to the IP3 binding domain of IP3R and may mediate a direct inhibitory effect. In summary, our findings suggest that H. cordata is a potential alternative treatment choice that may reduce asthma severity by targeting the dysregulation of Ca2+ signaling.
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Affiliation(s)
- Alexis Shiying Huang
- Teaching and Research Division, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region of China
| | - Benjamin Chun-Kit Tong
- Teaching and Research Division, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region of China
| | - Harry Chun-Hin Hung
- Teaching and Research Division, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region of China
| | - Aston Jiaxi Wu
- Teaching and Research Division, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region of China
| | - Olivia Ka-Yi Ho
- Teaching and Research Division, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region of China
| | - Anna Hau-Yee Kong
- Teaching and Research Division, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region of China
| | - Maggie Ming-Ki Leung
- Teaching and Research Division, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region of China
| | - Jingxuan Bai
- Teaching and Research Division, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region of China
| | - Xiuqiong Fu
- Teaching and Research Division, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region of China
| | - Zhiling Yu
- Teaching and Research Division, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region of China
| | - Min Li
- Teaching and Research Division, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region of China
| | - Ting Fan Leung
- Department of Paediatrics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Judith Choi-Wo Mak
- Department of Pharmacology and Pharmacy, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region of China
| | - George Pak-Heng Leung
- Department of Pharmacology and Pharmacy, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region of China
| | - King-Ho Cheung
- Teaching and Research Division, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region of China.
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Boucher M, Dufour-Mailhot A, Tremblay-Pitre S, Khadangi F, Rojas-Ruiz A, Henry C, Bossé Y. In mice of both sexes, repeated contractions of smooth muscle in vivo greatly enhance the response of peripheral airways to methacholine. Respir Physiol Neurobiol 2022; 304:103938. [PMID: 35716869 DOI: 10.1016/j.resp.2022.103938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/10/2022] [Accepted: 06/12/2022] [Indexed: 10/18/2022]
Abstract
BALB/c mice from both sexes underwent one of two nebulized methacholine challenges that were preceded by a period of 20 min either with or without tone induced by repeated contractions of the airway smooth muscle. Impedance was monitored throughout and the constant phase model was used to dissociate the impact of tone on conducting airways (RN - Newtonian resistance) versus the lung periphery (G and H - tissue resistance and elastance). The effect of tone on smooth muscle contractility was also tested on excised tracheas. While tone markedly potentiated the methacholine-induced gains in H and G in both sexes, the gain in RN was only potentiated in males. The contractility of female and male tracheas was also potentiated by tone. Inversely, the methacholine-induced gain in hysteresivity (G/H) was mitigated by tone in both sexes. Therefore, the tone-induced muscle hypercontractility impacts predominantly the lung periphery in vivo, but also promotes further airway narrowing in males while protecting against narrowing heterogeneity in both sexes.
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Affiliation(s)
- Magali Boucher
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Alexis Dufour-Mailhot
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Sophie Tremblay-Pitre
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Fatemeh Khadangi
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Andrés Rojas-Ruiz
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada.
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Gazzola M, Mailhot-Larouche S, Beucher C, Bossé Y. The underlying physiological mechanisms whereby anticholinergics alleviate asthma. Can J Physiol Pharmacol 2018; 96:433-441. [PMID: 29414243 DOI: 10.1139/cjpp-2017-0448] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The mechanisms whereby anticholinergics improve asthma outcomes, such as lung function, symptoms, and rate of exacerbation, can be numerous. The most obvious is by affecting the contraction of airway smooth muscle (ASM). The acetylcholine released from the cholinergic nerves is the most important bronchoconstrictor that sets the baseline degree of contractile activation of ASM in healthy individuals. Although the degree of ASM's contractile activation can also be fine-tuned by a plethora of other bronchoconstrictors and bronchodilators in asthma, blocking the ceaseless effect of acetylcholine on ASM by anticholinergics reduces, at any given moment, the overall degree of contractile activation. Because the relationships that exist between the degree of contractile activation, ASM force, ASM shortening, airway narrowing, airflow resistance, and respiratory resistance are not linear, small decreases in the contractile activation of ASM can be greatly amplified and thus translate into important benefits to a patient's well-being. Plus, many inflammatory and remodeling features that are often found in asthmatic lungs synergize with the contractile activation of ASM to increase respiratory resistance. This review recalls that the proven effectiveness of anticholinergics in the treatment of asthma could be merely attributed to a small reduction in the contractile activation of ASM.
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Affiliation(s)
- Morgan Gazzola
- Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada.,Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada
| | - Samuel Mailhot-Larouche
- Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada.,Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada
| | - Clémentine Beucher
- Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada.,Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada
| | - Ynuk Bossé
- Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada.,Quebec Heart and Lung Institute, affiliated with Université Laval, Quebec City, Quebec G1V 4G5, Canada
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Gazzola M, Lortie K, Henry C, Mailhot-Larouche S, Chapman DG, Couture C, Seow CY, Paré PD, King GG, Boulet LP, Bossé Y. Airway smooth muscle tone increases airway responsiveness in healthy young adults. Am J Physiol Lung Cell Mol Physiol 2016; 312:L348-L357. [PMID: 27941076 DOI: 10.1152/ajplung.00400.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 12/06/2016] [Accepted: 12/07/2016] [Indexed: 11/22/2022] Open
Abstract
Force adaptation, a process whereby sustained spasmogenic activation (viz., tone) of airway smooth muscle (ASM) increases its contractile capacity, has been reported in isolated ASM tissues in vitro, as well as in mice in vivo. The objective of the present study was to assess the effect of tone on airway responsiveness in humans. Ten healthy volunteers underwent methacholine challenge on two occasions. One challenge consisted of six serial doses of saline followed by a single high dose of methacholine. The other consisted of six low doses of methacholine 5 min apart followed by a higher dose. The cumulative dose was identical for both challenges. After both methacholine challenges, subjects took a deep inspiration (DI) to total lung capacity as another way to probe ASM mechanics. Responses to methacholine and the DI were measured using a multifrequency forced oscillation technique. Compared with a single high dose, the challenge preceded by tone led to an elevated response measured by respiratory system resistance (Rrs) and reactance at 5 Hz. However, there was no difference in the increase in Rrs at 19 Hz, suggesting a predominant effect on smaller airways. Increased tone also reduced the efficacy of DI, measured by an attenuated maximal dilation during the DI and an increased renarrowing post-DI. We conclude that ASM tone increases small airway responsiveness to inhaled methacholine and reduces the effectiveness of DI in healthy humans. This suggests that force adaptation may contribute to airway hyperresponsiveness and the reduced bronchodilatory effect of DI in asthma.
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Affiliation(s)
- Morgan Gazzola
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Katherine Lortie
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Samuel Mailhot-Larouche
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - David G Chapman
- Vermont Lung Center, University of Vermont College of Medicine, Burlington, Vermont
| | - Christian Couture
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Chun Y Seow
- University of British Columbia Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Peter D Paré
- University of British Columbia Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Gregory G King
- Woolcock Institute of Medical Research, Sydney, Australia.,University of Sydney, Sydney, Australia; and.,Cooperative Research Centre for Asthma, Sydney, Australia
| | - Louis-Philippe Boulet
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Québec, Canada;
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Duan Y, Long J, Chen J, Jiang X, Zhu J, Jin Y, Lin F, Zhong J, Xu R, Mao L, Deng L. Overexpression of soluble ADAM33 promotes a hypercontractile phenotype of the airway smooth muscle cell in rat. Exp Cell Res 2016; 349:109-118. [PMID: 27720670 DOI: 10.1016/j.yexcr.2016.10.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 10/01/2016] [Accepted: 10/03/2016] [Indexed: 12/28/2022]
Abstract
A disintegrin and metalloproteinase 33 (ADAM33) has been identified as a susceptibility gene for asthma, but details of the causality are not fully understood. We hypothesize that soluble ADAM33 (sADAM33) overexpression can alter the mechanical behaviors of airway smooth muscle cells (ASMCs) via regulation of the cell's contractile phenotype, and thus contributes to airway hyperresponsiveness (AHR) in asthma. To test this hypothesis, we either overexpressed or knocked down the sADAM33 in rat ASMCs by transfecting the cells with sADAM33 coding sequence or a small interfering RNA (siRNA) that specifically targets the ADAM33 disintegrin domain, and subsequently assessed the cells for stiffness, contractility and traction force, together with the expression level of contractile and proliferative phenotype markers. We also investigated whether these changes were dependent on Rho/ROCK pathway by culturing the ASMCs either in the absence or presence of ROCK inhibitor (H1152). The results showed that the ASMCs with sADAM33 overexpression were stiffer and more contractile, generated greater traction force, exhibited increased expression levels of contractile phenotype markers and markedly enhanced Rho activation. Furthermore these changes were largely attenuated when the cells were cultured in the presence of H-1152. However, the knock-down of ADAM33 seemed insufficient to influence majority of the mechanical behaviors of the ASMCs. Taken together, we demonstrated that sADAM33 overexpression altered the mechanical behaviors of ASMCs in vitro, which was most likely by promoting a hypercontractile phenotype transition of ASMCs through Rho/ROCK pathway. This revelation may establish the previously missing link between ADAM33 expression and AHR, and also provide useful insight for targeting sADAM33 in asthma prevention and therapy.
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Affiliation(s)
- Yiyuan Duan
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Bioengineering College, Chongqing University, Shapingba, Chongqing 400030, China
| | - Jiaoyue Long
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Bioengineering College, Chongqing University, Shapingba, Chongqing 400030, China
| | - Jun Chen
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Bioengineering College, Chongqing University, Shapingba, Chongqing 400030, China
| | - Xuemei Jiang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Bioengineering College, Chongqing University, Shapingba, Chongqing 400030, China
| | - Jian Zhu
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Bioengineering College, Chongqing University, Shapingba, Chongqing 400030, China
| | - Yang Jin
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Bioengineering College, Chongqing University, Shapingba, Chongqing 400030, China
| | - Feng Lin
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Bioengineering College, Chongqing University, Shapingba, Chongqing 400030, China
| | - Jun Zhong
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Bioengineering College, Chongqing University, Shapingba, Chongqing 400030, China
| | - Rong Xu
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Bioengineering College, Chongqing University, Shapingba, Chongqing 400030, China
| | - Lizheng Mao
- Jiangsu Asialand Biomed-Technology Co. Ltd., Changzhou, Jiangsu 213164, China
| | - Linhong Deng
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Bioengineering College, Chongqing University, Shapingba, Chongqing 400030, China; Changzhou Key Laboratory of Respiratory Medical Engineering, Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu 213164, China.
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Dowie J, Ansell TK, Noble PB, Donovan GM. Airway compliance and dynamics explain the apparent discrepancy in length adaptation between intact airways and smooth muscle strips. Respir Physiol Neurobiol 2015; 220:25-32. [PMID: 26376002 DOI: 10.1016/j.resp.2015.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 08/27/2015] [Accepted: 09/11/2015] [Indexed: 11/16/2022]
Abstract
Length adaptation is a phenomenon observed in airway smooth muscle (ASM) wherein over time there is a shift in the length-tension curve. There is potential for length adaptation to play an important role in airway constriction and airway hyper-responsiveness in asthma. Recent results by Ansell et al., 2015 (JAP 2014 10.1152/japplphysiol.00724.2014) have cast doubt on this role by testing for length adaptation using an intact airway preparation, rather than strips of ASM. Using this technique they found no evidence for length adaptation in intact airways. Here we attempt to resolve this apparent discrepancy by constructing a minimal mathematical model of the intact airway, including ASM which follows the classic length-tension curve and undergoes length adaptation. This allows us to show that (1) no evidence of length adaptation should be expected in large, cartilaginous, intact airways; (2) even in highly compliant peripheral airways, or at more compliant regions of the pressure-volume curve of large airways, the effect of length adaptation would be modest and at best marginally detectable in intact airways; (3) the key parameters which control the appearance of length adaptation in intact airways are airway compliance and the relaxation timescale. The results of this mathematical simulation suggest that length adaptation observed at the level of the isolated ASM may not clearly manifest in the normal intact airway.
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Affiliation(s)
- Jackson Dowie
- Department of Mathematics, University of Auckland, New Zealand
| | - Thomas K Ansell
- School of Veterinary and Life Sciences, Murdoch University, Australia; School of Anatomy, Physiology and Human Biology, The University of Western Australia, Australia
| | - Peter B Noble
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Australia; Centre for Neonatal Research and Education, The University of Western Australia, Australia
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Ansell TK, Noble PB, Mitchell HW, McFawn PK. Pharmacological bronchodilation is partially mediated by reduced airway wall stiffness. Br J Pharmacol 2015; 171:4376-84. [PMID: 24846164 DOI: 10.1111/bph.12781] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 03/31/2014] [Accepted: 04/25/2014] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND AND PURPOSE In asthmatic patients, airflow limitation is at least partly reversed by administration of pharmacological bronchodilators, typically β2 -adrenoceptor agonists. In addition to receptor-mediated bronchodilation, the dynamic mechanical environment of the lung itself can reverse bronchoconstriction. We have now explored the possibility that bronchodilators exert a synergistic effect with oscillatory loads by virtue of reducing airway wall stiffness, and therefore, enhancing the bronchodilatory response to breathing manoeuvres. EXPERIMENTAL APPROACH Whole porcine bronchial segments in vitro were contracted to carbachol and relaxed to the non-specific β-adrenoceptor agonist, isoprenaline, under static conditions or during simulated breathing manoeuvres. KEY RESULTS The bronchodilatory response to isoprenaline was greater during breathing manoeuvres compared with the response under static conditions. As the bronchodilatory response to breathing manoeuvres is dependent upon airway smooth muscle (ASM) strain, and therefore, airway wall stiffness, our findings are likely to be explained by the effect of isoprenaline on reducing airway wall stiffness, which increased ASM strain, producing greater bronchodilation. CONCLUSIONS AND IMPLICATIONS A contribution of reduced airway stiffness and increased ASM strain to the bronchodilator action of isoprenaline is shown, suggesting that oscillatory loads act synergistically with pharmacologically mediated bronchodilation. The implications for the treatment of asthma are that reducing airway wall stiffness represents a potential target for novel pharmacological agents.
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Affiliation(s)
- T K Ansell
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, WA, Australia
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Ansell TK, McFawn PK, McLaughlin RA, Sampson DD, Eastwood PR, Hillman DR, Mitchell HW, Noble PB. Does smooth muscle in an intact airway undergo length adaptation during a sustained change in transmural pressure? J Appl Physiol (1985) 2015; 118:533-43. [DOI: 10.1152/japplphysiol.00724.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In isolated airway smooth muscle (ASM) strips, an increase or decrease in ASM length away from its current optimum length causes an immediate reduction in force production followed by a gradual time-dependent recovery in force, a phenomenon termed length adaptation. In situ, length adaptation may be initiated by a change in transmural pressure (Ptm), which is a primary physiological determinant of ASM length. The present study sought to determine the effect of sustained changes in Ptm and therefore, ASM perimeter, on airway function. We measured contractile responses in whole porcine bronchial segments in vitro before and after a sustained inflation from a baseline Ptm of 5 cmH2O to 25 cmH2O, or deflation to −5 cmH2O, for ∼50 min in each case. In one group of airways, lumen narrowing and stiffening in response to electrical field stimulation (EFS) were assessed from volume and pressure signals using a servo-controlled syringe pump with pressure feedback. In a second group of airways, lumen narrowing and the perimeter of the ASM in situ were determined by anatomical optical coherence tomography. In a third group of airways, active tension was determined under isovolumic conditions. Both inflation and deflation reduced the contractile response to EFS. Sustained Ptm change resulted in a further decrease in contractile response, which returned to baseline levels upon return to the baseline Ptm. These findings reaffirm the importance of Ptm in regulating airway narrowing. However, they do not support a role for ASM length adaptation in situ under physiological levels of ASM lengthening and shortening.
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Affiliation(s)
- Thomas K. Ansell
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, Australia
| | - Peter K. McFawn
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia
| | - Robert A. McLaughlin
- Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
| | - David D. Sampson
- Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Crawley, Western Australia, Australia
| | - Peter R. Eastwood
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia
- West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; and
| | - David R. Hillman
- West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; and
| | - Howard W. Mitchell
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia
| | - Peter B. Noble
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia
- Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Crawley, Western Australia, Australia
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D'Amato M, Stanziola AA, de Laurentiis G, Diana R, Russo C, Maniscalco M, D'Amato G, Sofia M. Nocturnal continuous positive airway pressure in severe non-apneic asthma. A pilot study. CLINICAL RESPIRATORY JOURNAL 2014; 8:417-24. [PMID: 24308356 DOI: 10.1111/crj.12088] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 10/01/2013] [Accepted: 12/02/2013] [Indexed: 01/23/2023]
Abstract
INTRODUCTION It has been demonstrated that brief periods of nocturnal continuous positive airway pressure (nCPAP) reduce airway reactivity in animal models and in patients with asthma. The effects of nCPAP in severe uncontrolled non-apneic asthmatic patients are not well known. AIM In this open pilot study, we aimed to assess the effect nCPAP on peak flow (PEF) variability and asthma control in this type of patients. METHODS CPAP was applied to 10 patients with severe long-standing asthma without obstructive sleep apnea for seven consecutive nights. CPAP was titrated in auto setting and applied to the patients. Daily PEF, was measured from 2 weeks before the intervention to 2 weeks after the end of nCPAP treatment. PEF amplitude and PEF morning dip (MD) over 24-h periods averaged over 1 week were calculated as indexes of PEF variability. Asthma control test (ACT) and European quality of life (EuroQol) questionnaire were measured at baseline and after 1 month, and at baseline and at the end of CPAP period, respectively. RESULTS The PEF amplitude significantly decreased both during CPAP period and in the first week after nCPAP discontinuation as compared with the baseline (19.8 ± 7.5%, 23.9 ± 9.1% and 28.9 ± 11.5%, respectively, always P < 0.05). PEF MD significantly decreased during nCPAP in comparison with the baseline (P < 0.001). The ACT and EuroQol significantly improved after nCPAP in comparison with the basal value. CONCLUSIONS In this preliminary report, brief period of nCPAP reduces PEF variability and improves control in severe non-apneic asthma at a short-term evaluation. Further studies with longer-term evaluation and larger number of patients are warranted.
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Affiliation(s)
- Maria D'Amato
- Department of Respiratory Diseases, University Federico II of Naples, Naples, Italy
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11
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Doeing DC, Solway J. Airway smooth muscle in the pathophysiology and treatment of asthma. J Appl Physiol (1985) 2013; 114:834-43. [PMID: 23305987 DOI: 10.1152/japplphysiol.00950.2012] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Airway smooth muscle (ASM) plays an integral part in the pathophysiology of asthma. It is responsible for acute bronchoconstriction, which is potentiated by constrictor hyperresponsiveness, impaired relaxation and length adaptation. ASM also contributes to airway remodeling and inflammation in asthma. In light of this, ASM is an important target in the treatment of asthma.
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Affiliation(s)
- Diana C Doeing
- Department of Medicine, University of Chicago, Chicago, IL, USA.
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12
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A Brief History of Airway Smooth Muscle's Role in Airway Hyperresponsiveness. J Allergy (Cairo) 2012; 2012:768982. [PMID: 23118776 PMCID: PMC3483821 DOI: 10.1155/2012/768982] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 09/21/2012] [Indexed: 11/18/2022] Open
Abstract
A link between airway smooth muscle (ASM) and airway hyperresponsiveness (AHR) in asthma was first postulated in the midnineteenth century, and the suspected link has garnered ever increasing interest over the years. AHR is characterized by excessive narrowing of airways in response to nonspecific stimuli, and it is the ASM that drives this narrowing. The stimuli that can be used to demonstrate AHR vary widely, as do the potential mechanisms by which phenotypic changes in ASM or nonmuscle factors can contribute to AHR. In this paper, we review the history of research on airway smooth muscle's role in airway hyperresponsiveness. This research has ranged from analyzing the quantity of ASM in the airways to testing for alterations in the plastic behavior of smooth muscle, which distinguishes it from skeletal and cardiac muscles. This long history of research and the continued interest in this topic mean that the precise role of ASM in airway responsiveness remains elusive, which makes it a pertinent topic for this collection of articles.
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13
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Wylam ME, Xue A, Sieck GC. Mechanisms of intrinsic force in small human airways. Respir Physiol Neurobiol 2012; 181:99-108. [PMID: 22322114 DOI: 10.1016/j.resp.2012.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 01/24/2012] [Accepted: 01/25/2012] [Indexed: 10/14/2022]
Abstract
We quantified the magnitude and investigated mechanisms regulating intrinsic force (IF) in human airway smooth muscle (hASM). IF was identified by reducing extracellular calcium (Ca2+) concentration to nominally zero in freshly isolated isometrically mounted 2mm human bronchi. Our results show: (1) the magnitude of IF is ∼50% of the maximal total force elicited by acetylcholine (10(-5) M) and is epithelial independent, (2) IF can also be revealed by β-adrenergic activation (isoproterenol), non-specific cationic channel blockade (La3+) or L-type voltage gated Ca2+ channel blockade (nifedipine), (3) atropine, indomethacin, AA-861, or pyrilamine did not affect IF, (4) IF was reduced by the intracellular Ca2+ ([Ca2+]i) chelating agent BAPTA-AM, (5) ω-conotoxin had no effect on IF. In studies in cultured hASM cells nominally zero Ca2+ buffer and BAPTA-AM reduced [Ca2+]i but isoproterenol and nifedipine did not. Taken together these results indicate that rapid reduction of [Ca2+]i reveals a permissive relationship between extracellular Ca2+, [Ca2+]i and IF. However IF can be dissipated by mechanisms effecting Ca2+ sensitivity. We speculate that an increase of IF, a fundamental property of ASM, could be related to human airway clinical hyperresponsiveness and must be accounted for in in vitro studies of hASM.
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Affiliation(s)
- Mark E Wylam
- Division of Pulmonary and Critical Care Medicine, Departments of Medicine, Pediatrics, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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14
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Pellegrino R, Pellegrino GM, Brusasco V. CPAP as a novel treatment for bronchial asthma? J Appl Physiol (1985) 2011; 111:343-4. [PMID: 21659492 DOI: 10.1152/japplphysiol.00676.2011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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15
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Chiba Y, Matsusue K, Misawa M. RhoA, a possible target for treatment of airway hyperresponsiveness in bronchial asthma. J Pharmacol Sci 2010; 114:239-47. [PMID: 20948164 DOI: 10.1254/jphs.10r03cr] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Airway hyperresponsiveness to nonspecific stimuli is one of the characteristic features of allergic bronchial asthma. An elevated contractility of bronchial smooth muscle has been considered as one of the causes of the airway hyperresponsiveness. The contraction of smooth muscles including airway smooth muscles is mediated by both Ca²+-dependent and Ca²+-independent pathways. The latter Ca²+-independent pathway, termed Ca²+ sensitization, is mainly regulated by a monomeric GTP-binding protein, RhoA, and its downstream target Rho-kinase. In animal models of allergic bronchial asthma, an augmented agonist-induced, RhoA-mediated contraction of bronchial smooth muscle has been suggested. The RhoA/Rho-kinase signaling is now proposed as a novel target for the treatment of airway hyperresponsiveness in asthma. Herein, we will discuss the mechanism of development of bronchial smooth muscle hyperresponsiveness, one of the causes of the airway hyperresponsiveness, based on the recent studies using animal models of allergic bronchial asthma and/or cultured airway smooth muscle cells. The possibility of RhoA as a therapeutic target in asthma, especially airway hyperresponsiveness, will also be described.
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Affiliation(s)
- Yoshihiko Chiba
- Department of Pharmacology, School of Pharmacy, Hoshi University, Japan.
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16
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Bossé Y, Riesenfeld EP, Paré PD, Irvin CG. It's Not All Smooth Muscle: Non-Smooth-Muscle Elements in Control of Resistance to Airflow. Annu Rev Physiol 2010; 72:437-62. [DOI: 10.1146/annurev-physiol-021909-135851] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ynuk Bossé
- The James Hogg iCAPTURE Center for Cardiovascular and Pulmonary Research, Providence Health Care/St. Paul's Hospital, Department of Medicine, Respiratory Division, University of British Columbia, Vancouver, British Columbia, V6Z 1Y6; ,
| | - Erik P. Riesenfeld
- Vermont Lung Center, Department of Medicine, Pulmonary and Critical Care Medicine, University of Vermont College of Medicine, Burlington, Vermont 05405; ,
| | - Peter D. Paré
- The James Hogg iCAPTURE Center for Cardiovascular and Pulmonary Research, Providence Health Care/St. Paul's Hospital, Department of Medicine, Respiratory Division, University of British Columbia, Vancouver, British Columbia, V6Z 1Y6; ,
| | - Charles G. Irvin
- Vermont Lung Center, Department of Medicine, Pulmonary and Critical Care Medicine, University of Vermont College of Medicine, Burlington, Vermont 05405; ,
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17
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Bossé Y, Solomon D, Chin LYM, Lian K, Paré PD, Seow CY. Increase in passive stiffness at reduced airway smooth muscle length: potential impact on airway responsiveness. Am J Physiol Lung Cell Mol Physiol 2010; 298:L277-87. [DOI: 10.1152/ajplung.00275.2009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The amplitude of strain in airway smooth muscle (ASM) produced by oscillatory perturbations such as tidal breathing or deep inspiration (DI) influences the force loss in the muscle and is therefore a key determinant of the bronchoprotective and bronchodilatory effects of these breathing maneuvers. The stiffness of unstimulated ASM (passive stiffness) directly influences the amplitude of strain. The nature of the passive stiffness is, however, not clear. In this study, we measured the passive stiffness of ovine ASM at different muscle lengths (relative to in situ length, which was used as a reference length, Lref) and states of adaptation to gain insights into the origin of this muscle property. The results showed that the passive stiffness was relatively independent of muscle length, possessing a constant plateau value over a length range from 0.62 to 1.25 Lref. Following a halving of ASM length, passive stiffness decreased substantially (by 71%) but redeveloped over time (∼30 min) at the shorter length to reach 65% of the stiffness value at Lref, provided that the muscle was stimulated to contract at least once over a ∼30-min period. The redevelopment and maintenance of passive stiffness were dependent on the presence of Ca2+ but unaffected by latrunculin B, an inhibitor of actin filament polymerization. The maintenance of passive stiffness was also not affected by blocking myosin cross-bridge cycling using a myosin light chain kinase inhibitor or by blocking the Rho-Rho kinase (RhoK) pathway using a RhoK inhibitor. Our results suggest that the passive stiffness of ASM is labile and capable of redevelopment following length reduction. Redevelopment and maintenance of passive stiffness following muscle shortening could contribute to airway hyperresponsiveness by attenuating the airway wall strain induced by tidal breathing and DI.
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Affiliation(s)
- Ynuk Bossé
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, Providence Health Care/St. Paul's Hospital,
| | - Dennis Solomon
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, Providence Health Care/St. Paul's Hospital,
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Leslie Y. M. Chin
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, Providence Health Care/St. Paul's Hospital,
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kevin Lian
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, Providence Health Care/St. Paul's Hospital,
| | - Peter D. Paré
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, Providence Health Care/St. Paul's Hospital,
- Department of Medicine, Respiratory Division, and
| | - Chun Y. Seow
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, Providence Health Care/St. Paul's Hospital,
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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18
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Bossé Y, Chin LYM, Paré PD, Seow CY. Chronic activation in shortened airway smooth muscle: a synergistic combination underlying airway hyperresponsiveness? Am J Respir Cell Mol Biol 2009; 42:341-8. [PMID: 19448153 DOI: 10.1165/rcmb.2008-0448oc] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Airway smooth muscle (ASM) in individuals with asthma is continuously stimulated by spasmogens released as part of chronic airway inflammation. This chronic submaximal stimulation of ASM produces "tone," which may or may not narrow airways sufficiently to induce respiratory symptoms. However, when coupled with a bronchoprovocative challenge with a nonspecific contractile agonist, this increased tone could contribute to the manifestation of airway hyperresponsiveness (AHR). In this study, we examined the effect of chronic acetylcholine (ACh) exposure at different muscle lengths to gain insights into the consequence of increased tone on the mechanical properties of ASM. The total force (the ACh-induced tone plus active force induced by a second stimulus-electric field stimulation [EFS]) increased immediately after induction of muscle tone, and increased further over time in the presence of the tone in a process termed "force adaptation." The phenomenon of force adaptation was observed over a wide range of muscle lengths and did not prevent length adaptation when the muscle was adapted to the tone before being subjected to a length change, suggesting that both length and force adaptations can occur sequentially and in an independent fashion in the same tissue. Together, these results suggest that adaptation of ASM to shortened length in the presence of muscle tone produced a condition that favored excessive force generation in response to a second stimulus (herein EFS) at reduced muscle length. In vivo these changes will be translated into excessive airway narrowing in response to naturally occurring and pharmacological bronchoconstricting stimuli.
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Affiliation(s)
- Ynuk Bossé
- The James Hogg iCAPTURE Centre, Providence Health Care/St. Paul's Hospital, Vancouver, BC, V6Z 1Y6 Canada
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19
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Deng L, Bosse Y, Brown N, Chin LYM, Connolly SC, Fairbank NJ, King GG, Maksym GN, Paré PD, Seow CY, Stephen NL. Stress and strain in the contractile and cytoskeletal filaments of airway smooth muscle. Pulm Pharmacol Ther 2009; 22:407-16. [PMID: 19409505 DOI: 10.1016/j.pupt.2009.04.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Revised: 04/16/2009] [Accepted: 04/21/2009] [Indexed: 10/20/2022]
Abstract
Stress and strain are omnipresent in the lung due to constant lung volume fluctuation associated with respiration, and they modulate the phenotype and function of all cells residing in the airways including the airway smooth muscle (ASM) cell. There is ample evidence that the ASM cell is very sensitive to its physical environment, and can alter its structure and/or function accordingly, resulting in either desired or undesired consequences. The forces that are either conferred to the ASM cell due to external stretching or generated inside the cell must be borne and transmitted inside the cytoskeleton (CSK). Thus, maintaining appropriate levels of stress and strain within the CSK is essential for maintaining normal function. Despite the importance, the mechanisms regulating/dysregulating ASM cytoskeletal filaments in response to stress and strain remained poorly understood until only recently. For example, it is now understood that ASM length and force are dynamically regulated, and both can adapt over a wide range of length, rendering ASM one of the most malleable living tissues. The malleability reflects the CSK's dynamic mechanical properties and plasticity, both of which strongly interact with the loading on the CSK, and all together ultimately determines airway narrowing in pathology. Here we review the latest advances in our understanding of stress and strain in ASM cells, including the organization of contractile and cytoskeletal filaments, range and adaptation of functional length, structural and functional changes of the cell in response to mechanical perturbation, ASM tone as a mediator of strain-induced responses, and the novel glassy dynamic behaviors of the CSK in relation to asthma pathophysiology.
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Affiliation(s)
- Linhong Deng
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, and National 985 Project Institute of Biorheology and Gene Regulation, Bioengineering College, Chongqing University, Chongqing, China.
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20
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Bai Y, Sanderson MJ. The contribution of Ca2+ signaling and Ca2+ sensitivity to the regulation of airway smooth muscle contraction is different in rats and mice. Am J Physiol Lung Cell Mol Physiol 2009; 296:L947-58. [PMID: 19346434 DOI: 10.1152/ajplung.90288.2008] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To determine the relative contributions of Ca(2+) signaling and Ca(2+) sensitivity to the contractility of airway smooth muscle cells (SMCs), we compared the contractile responses of mouse and rat airways with the lung slice technique. Airway contraction was measured by monitoring changes in airway lumen area with phase-contrast microscopy, whereas changes in intracellular calcium concentration ([Ca(2+)](i)) of the SMCs were recorded with laser scanning microscopy. In mice and rats, methacholine (MCh) or serotonin induced concentration-dependent airway contraction and Ca(2+) oscillations in the SMCs. However, rat airways demonstrated greater contraction compared with mice, in response to agonist-induced Ca(2+) oscillations of a similar frequency. Because this indicates that rat airway SMCs have a higher Ca(2+) sensitivity compared with mice, we examined Ca(2+) sensitivity with Ca(2+)-permeabilized airway SMCs in which the [Ca(2+)](i) was experimentally controlled. In the absence of agonists, high [Ca(2+)](i) induced a sustained contraction in rat airways but only a transient contraction in mouse airways. This sustained contraction of rat airways was relaxed by Y-23672, a Rho kinase inhibitor, but not affected by GF-109203X, a PKC inhibitor. The subsequent exposure of Ca(2+)-permeabilized airway SMCs, with high [Ca(2+)](i), to MCh elicited a further contraction of rat airways and initiated a sustained contraction of mouse airways, without changing the [Ca(2+)](i) of the SMCs. Collectively, these results indicate that airway SMCs of rats have a substantially higher innate Ca(2+) sensitivity than mice and that this strongly influences the transduction of the frequency of Ca(2+) oscillations into the contractility of airway SMCs.
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Affiliation(s)
- Yan Bai
- Dept. of Physiology, Univ. of Massachusetts Medical School, 55 Lake Ave. North, Worcester, MA 01655, USA
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21
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Role of protein kinase C α and cyclin D1 in the proliferation of airway smooth muscle in asthmatic rats. Chin Med J (Engl) 2008. [DOI: 10.1097/00029330-200810020-00024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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22
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Bossé Y, Paré PD, Seow CY. Airway wall remodeling in asthma: from the epithelial layer to the adventitia. Curr Allergy Asthma Rep 2008; 8:357-66. [PMID: 18606090 DOI: 10.1007/s11882-008-0056-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Asthma is an episodic respiratory syndrome caused by several pathogenic processes. This recurrent syndrome is associated with an accelerated decline in lung function and increase in airway obstruction over time. The reduced lung function is a consequence of tissue restructuring of all the components of the airway wall: 1) epithelium metaplasia; 2) altered quantity, composition, and distribution of extracellular matrix components; 3) microvascular remodeling; and 4) increase of airway smooth muscle mass. How these structural changes affect lung functions is not entirely clear. Deeper understandings of the altered structure and related functional impairment are important for gaining insights into the mechanisms underlying asthma. This review describes the tissue remodeling observed in different compartments of the asthmatic airway wall, from the airway lumen to adventitia. The underlying mechanisms driving the remodeling processes are also briefly reviewed.
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Affiliation(s)
- Ynuk Bossé
- James Hogg iCAPTURE Centre/St. Paul's Hospital, Room 166, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada.
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23
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Bossé Y, Chin LYM, Paré PD, Seow CY. Adaptation of airway smooth muscle to basal tone: relevance to airway hyperresponsiveness. Am J Respir Cell Mol Biol 2008; 40:13-8. [PMID: 18617678 DOI: 10.1165/rcmb.2008-0150oc] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Lung inflammation and airway hyperresponsiveness (AHR) are hallmarks of asthma, but their interrelationship is unclear. Excessive shortening of airway smooth muscle (ASM) in response to bronchoconstrictors is likely an important determinant of AHR. Hypercontractility of ASM could stem from a change in the intrinsic properties of the muscle, or it could be due to extrinsic factors such as chronic exposure of the muscle to inflammatory mediators in the airways. The latter could be the link between lung inflammation and AHR. The present study was designed to examine the influence of chronic exposure to a contractile agonist on the force-generating capacity of ASM. Force generation in response to electric field stimulation (EFS) was measured in ovine trachealis with or without a basal tone induced by acetylcholine (ACh). While the tone was maintained, the EFS-induced force decreased transiently but increased over time to reach a plateau in approximately 50 minutes. The total force (ACh tone + EFS force) increased monotonically and in proportion to ACh concentration. The results indicate that the muscle adapted to the basal tone and regained its contractile ability in response to a second stimulus (EFS) over time. Analysis suggests that this is due to a cytoskeletal transformation that allows the cytoskeleton to bear force, thus freeing up actomyosin crossbridges to generate more force. Force adaptation in ASM as a consequence of prolonged exposure to the many spasmogens found in asthmatic airways could be a mechanism contributing to AHR seen in asthma.
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Affiliation(s)
- Ynuk Bossé
- the James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research/St. Paul's Hospital, Room 166-1081, Burrard Street, Vancouver, BC, V6Z 1Y6 Canada.
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24
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Paré PD, McParland BE, Seow CY. Structural basis for exaggerated airway narrowing. Can J Physiol Pharmacol 2007; 85:653-8. [PMID: 17823628 DOI: 10.1139/y07-051] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Airway hyperresponsiveness, particularly the ability of airways to narrow excessively in response to stimuli that normally cause little airway narrowing in nonasthmatic subjects, is a characteristic feature of asthma and the basis of its symptoms. Although airway hyperresponsiveness may be partly the result of alterations in the contractile phenotype of the airway smooth muscle, there is evidence that it may also be caused by structural changes in the airway wall, collectively termed airway remodeling. Airway remodeling is defined as changes in composition, quantity, and (or) organization of cellular and molecular constituents of the airway wall. Airway wall remodeling that occurs in asthma can result in functional alterations because of quantitative changes in airway wall compartments, and (or) because of changes in the biochemical composition or material properties of the various constituents of the airway wall. This brief review summarizes the quantitative changes in the dimensions and organization of the airway wall compartments that have been described and explains how structural alterations may lead to the exaggerated airway narrowing.
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Affiliation(s)
- Peter D Paré
- Department of Medicine and Respiratory Division and The James Hogg iCAPTURE Centre, St Paul's Hospital, University of British Columbia, Vancouver, BC, Canada.
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25
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Ip K, Sobieszek A, Solomon D, Jiao Y, Paré PD, Seow CY. Physical integrity of smooth muscle myosin filaments is enhanced by phosphorylation of the regulatory myosin light chain. Cell Physiol Biochem 2007; 20:649-58. [PMID: 17762191 DOI: 10.1159/000107548] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND AND AIMS Smooth muscle myosin monomers self-assemble in solution to form filaments. Phosphorylation of the 20-kD regulatory myosin light chain (MLC20) enhances filament formation. It is not known whether the phosphorylated and non-phosphorylated filaments possess the same structural integrity. METHODS We purified myosin from bovine trachealis to form filaments, in ATP-containing zero-calcium solution during a slow dialysis that gradually reduced the ionic strength. Sufficient myosin light chain kinase and phosphatase, as well as calmodulin, were retained after the myosin purification and this enabled phosphorylation of MLC20 within 20-40s after addition of calcium to the filament suspension. The phosphorylated and non-phosphorylated filaments were then partially disassembled by ultrasonification. The extent of filament disintegration was visualized and quantified by atomic force microscopy. RESULTS MLC20 phosphorylation reduced the diameter of the filaments and rendered the filaments more resistant to ultrasonic agitation. Electron microscopy revealed a similar reduction in filament diameter in intact smooth muscle when the cells were activated. CONCLUSION Modification of the structural and physical properties of myosin filaments by MLC20 phosphorylation may be a key regulation step in smooth muscle where formation and dissolution of the filaments are required in the cells' adaptation to different cell length.
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Affiliation(s)
- Kelvin Ip
- James Hogg iCAPTURE Centre, St. Paul's Hospital, Vancouver, Canada
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26
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Ali F, Chin L, Paré PD, Seow CY. Mechanism of partial adaptation in airway smooth muscle after a step change in length. J Appl Physiol (1985) 2007; 103:569-77. [PMID: 17495118 DOI: 10.1152/japplphysiol.00216.2007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The phenomenon of length adaptation in airway smooth muscle (ASM) is well documented; however, the underlying mechanism is less clear. Evidence to date suggests that the adaptation involves reassembly of contractile filaments, leading to reconfiguration of the actin filament lattice and polymerization or depolymerization of the myosin filaments within the lattice. The time courses for these events are unknown. To gain insights into the adaptation process, we examined ASM mechanical properties and ultrastructural changes during adaptation. Step changes in length were applied to isolated bundles of ASM cells; changes in force, shortening velocity, and myosin filament mass were then quantified. A greater decrease in force was found following an acute decrease in length, compared with that of an acute increase in length. A decrease in myosin filament mass was also found with an acute decrease in length. The shortening velocity measured immediately after the length change was the same as that measured after the muscle had fully adapted to the new length. These observations can be explained by a model in which partial adaptation of the muscle leads to an intermediate state in which reconfiguration of the myofilament lattice occurred rapidly, followed by a relatively slow process of polymerization of myosin filaments within the lattice. The partially adapted intermediate state is perhaps more physiologically relevant than the fully adapted state seen under static conditions, and it simulates a more realistic behavior for ASM in vivo.
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Affiliation(s)
- Farah Ali
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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27
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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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Affonce DA, Lutchen KR. New perspectives on the mechanical basis for airway hyperreactivity and airway hypersensitivity in asthma. J Appl Physiol (1985) 2006; 101:1710-9. [PMID: 16902064 DOI: 10.1152/japplphysiol.00344.2006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We revisit the airway wall model of Lambert et. al. (Lambert RK, Wiggs BR, Kuwano K, Hogg JC, and Pare PD. J Appl Physiol 74: 2771-2781, 1993). We examine in detail the notion of a general airway bistability such that the airway lumen can suddenly decrease from a relatively open to a relatively closed condition without needing additional increase in active airway smooth muscle (ASM) tension during the stimulation. The onset of this bistability is an emergent consequence of the balance of forces associated with airway wall properties, parenchymal tissue properties, maximum lung elastic recoil, and the maximum stress that the ASM can generate. In healthy lungs, we find that all these properties reside in conditions that largely prevent the emergence of the bistability even during maximum ASM stimulation. In asthmatic airways, however, the airway wall and ASM remodeling conditions can tip the balance so as to promote the onset of the bistability at a lower dose of ASM stimulation (enhanced sensitivity) and then work to amplify the maximum constriction reached by each airway (enhanced reactivity). Hence, a larger fraction of asthmatic airways can display overall airway hyperreactivity. Simulations studies examine the role of increasing ASM maximum tension, airway wall stiffening, reduced lung volume, and decreased parenchymal tethering. Results predict that the single most important factor causing this airway hyperreactivity is amplified maximum ASM tension and not a thickening of the airway wall per se.
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Affiliation(s)
- Derek A Affonce
- Biomedical Engineering Department, Boston University, 44 Cummington St., Boston, MA 02215, USA.
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Seow CY. Myosin filament assembly in an ever-changing myofilament lattice of smooth muscle. Am J Physiol Cell Physiol 2006; 289:C1363-8. [PMID: 16275736 DOI: 10.1152/ajpcell.00329.2005] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A major development in smooth muscle research in recent years is the recognition that the myofilament lattice of the muscle is malleable. The malleability appears to stem from plastic rearrangement of contractile and cytoskeletal filaments in response to stress and strain exerted on the muscle cell, and it allows the muscle to adapt to a wide range of cell lengths and maintain optimal contractility. Although much is still poorly understood, we have begun to comprehend some of the basic mechanisms underlying the assembly and disassembly of contractile and cytoskeletal filaments in smooth muscle during the process of adaptation to large changes in cell geometry. One factor that likely facilitates the plastic length adaptation is the ability of myosin filaments to form and dissolve at the right place and the right time within the myofilament lattice. It is proposed herein that formation of myosin filaments in vivo is aided by the various filament-stabilizing proteins, such as caldesmon, and that the thick filament length is determined by the dimension of the actin filament lattice. It is still an open question as to how the dimension of the dynamic filament lattice is regulated. In light of the new perspective of malleable myofilament lattice in smooth muscle, the roles of many smooth muscle proteins could be assigned or reassigned in the context of plastic reorganization of the contractile apparatus and cytoskeleton.
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Affiliation(s)
- Chun Y Seow
- Department of Pathology and Laboratory Medicine, James Hogg iCAPTURE Centre, St. Paul's Hospital, Rm. 166, 1081 Burrard St., Vancouver, BC, Canada V6Z 1Y6.
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