Oenema Tjitske A, Maarsingh Harm, Smit Marieke, Groothuis Geny M M, Meurs Herman, Gosens Reinoud
Department of Molecular Pharmacology, Groningen Research Institute for Asthma and COPD, University of Groningen, Groningen, The Netherlands ; Groningen Research Institute for Asthma and COPD (GRIAC), University of Groningen, Groningen, The Netherlands.
PLoS One. 2013 Jun 26;8(6):e65580. doi: 10.1371/journal.pone.0065580. Print 2013.
Airway remodelling, including smooth muscle remodelling, is a primary cause of airflow limitation in asthma. Recent evidence links bronchoconstriction to airway remodelling in asthma. The mechanisms involved are poorly understood. A possible player is the multifunctional cytokine TGF-β, which plays an important role in airway remodelling. Guinea pig lung slices were used as an in vitro model to investigate mechanisms involved in bronchoconstriction-induced airway remodelling. To address this aim, mechanical effects of bronchoconstricting stimuli on contractile protein expression and TGF-β release were investigated. Lung slices were viable for at least 48 h. Both methacholine and TGF-β1 augmented the expression of contractile proteins (sm-α-actin, sm-myosin, calponin) after 48 h. Confocal fluorescence microscopy showed that increased sm-myosin expression was enhanced in the peripheral airways and the central airways. Mechanistic studies demonstrated that methacholine-induced bronchoconstriction mediated the release of biologically active TGF-β, which caused the increased contractile protein expression, as inhibition of actin polymerization (latrunculin A) or TGF-β receptor kinase (SB431542) prevented the methacholine effects, whereas other bronchoconstricting agents (histamine and KCl) mimicked the effects of methacholine. Collectively, bronchoconstriction promotes the release of TGF-β, which induces airway smooth muscle remodelling. This study shows that lung slices are a useful in vitro model to study mechanisms involved in airway remodelling.
气道重塑，包括平滑肌重塑，是哮喘气流受限的主要原因。最近的证据表明支气管收缩与哮喘气道重塑有关。其涉及的机制尚不清楚。多功能细胞因子转化生长因子-β（TGF-β）可能是其中一个因素，它在气道重塑中起重要作用。豚鼠肺切片被用作体外模型来研究支气管收缩诱导气道重塑的机制。为实现这一目标，研究了支气管收缩刺激对收缩蛋白表达和TGF-β释放的机械效应。肺切片至少存活48小时。48小时后，乙酰甲胆碱和TGF-β1均增加了收缩蛋白（平滑肌α-肌动蛋白、平滑肌肌球蛋白、钙调蛋白）的表达。共聚焦荧光显微镜显示，外周气道和中央气道中平滑肌肌球蛋白表达增加。机制研究表明，乙酰甲胆碱诱导的支气管收缩介导了生物活性TGF-β的释放，这导致收缩蛋白表达增加，因为抑制肌动蛋白聚合（拉春库林A）或TGF-β受体激酶（SB431542）可阻止乙酰甲胆碱的作用，而其他支气管收缩剂（组胺和氯化钾）模拟了乙酰甲胆碱的作用。总体而言，支气管收缩促进TGF-β的释放，TGF-β诱导气道平滑肌重塑。本研究表明，肺切片是研究气道重塑机制的有用体外模型。
