Department of Respiratory Disease, Academy of Orthopedics of Guangdong Province, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China; Department of Respiratory Disease, Hengyang NO.1 Peoples Hospital, Hengyang, Hunan, China.
Department of Respiratory Disease, Academy of Orthopedics of Guangdong Province, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China.
Life Sci. 2018 Mar 15;197:130-139. doi: 10.1016/j.lfs.2018.02.012. Epub 2018 Feb 8.
Thrombin is a serine proteinase that is not only involved in coagulation cascade, but also mediates a number of biological responses relevant to tissues repair, and induces bronchoconstriction. TGF-β plays a pivotal role in airway remodeling due to its effects on airway smooth muscle proliferation and extracellular matrix (ECM) deposition. Recently, bronchoconstriction itself is found to constitute a form of strain and is highly relevant to asthmatic airway remodeling. However, the underlying mechanisms remain unknown. Here, we investigated the role of contraction- dependent TGF-β activation in thrombin-induced remodeling in human airway smooth muscle (HASM) cells.
Primary HASM cells were treated with or without thrombin in the absence or presence of anti-TGF-β antibody, cytochalasin D and formoterol. CFSE labeling index or CCK-8 assay were performed to test cell proliferation. RT-PCR and Western blotting were used to examined ECM mRNA level and collagen Iα1, α-actin protein expression, respectively. Immunofluorescence was also used to confirm contraction induced by thrombin in HASM cells.
Thrombin stimulation enhanced HASM cells proliferation and activated TGF-β signaling. Thrombin induced ECM mRNA and collagen Iα1 protein expression, and these effects are mediated by TGF-β. Abrogation of TGF-β activation by contraction inhibitors cytochalasin D and formoterol prevents the thrombin-induced effects.
These findings suggest that contraction-dependent TGF-β activation could be a mechanism by which thrombin leads to the development of asthmatic airway remodeling. Blocking physical forces with bronchodilator would be an intriguing way in reducing airway remodeling in asthma.
凝血酶是一种丝氨酸蛋白酶，不仅参与凝血级联反应，还介导与组织修复相关的许多生物学反应，并引起支气管收缩。TGF-β 通过影响气道平滑肌增殖和细胞外基质（ECM）沉积，在气道重塑中起关键作用。最近，支气管收缩本身被发现构成一种应变形式，与哮喘气道重塑高度相关。然而，其潜在机制尚不清楚。在这里，我们研究了收缩依赖性 TGF-β 激活在凝血酶诱导的人气道平滑肌（HASM）细胞重塑中的作用。
用或不用凝血酶处理原代 HASM 细胞，同时存在或不存在抗 TGF-β 抗体、细胞松弛素 D 和福莫特罗。CFSE 标记指数或 CCK-8 测定法用于测试细胞增殖。RT-PCR 和 Western blot 用于分别检测 ECM mRNA 水平和胶原 Iα1、α-肌动蛋白蛋白表达。免疫荧光也用于证实凝血酶在 HASM 细胞中的收缩作用。
凝血酶刺激增强 HASM 细胞增殖并激活 TGF-β 信号通路。凝血酶诱导 ECM mRNA 和胶原 Iα1 蛋白表达，这些作用是由 TGF-β 介导的。收缩抑制剂细胞松弛素 D 和福莫特罗阻断 TGF-β 激活可防止凝血酶诱导的作用。
这些发现表明，收缩依赖性 TGF-β 激活可能是凝血酶导致哮喘气道重塑发展的一种机制。用支气管扩张剂阻断物理力可能是减少哮喘气道重塑的一种有趣方法。
