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Dong HM, Le YQ, Wang YH, Zhao HJ, Huang CW, Hu YH, Luo LS, Wan X, Wei YL, Chu ZQ, Li W, Cai SX. Extracellular heat shock protein 90α mediates HDM-induced bronchial epithelial barrier dysfunction by activating RhoA/MLC signaling. Respir Res 2017; 18:111. [PMID: 28558721 PMCID: PMC5450201 DOI: 10.1186/s12931-017-0593-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/19/2017] [Indexed: 12/13/2022] Open
Abstract
Background The disruption and hyperpermeability of bronchial epithelial barrier are closely related to the pathogenesis of asthma. House dust mite (HDM), one of the most important allergens, could increase the airway epithelial permeability. Heat shock protein (Hsp) 90α is also implicated in the lung endothelial barrier dysfunction by disrupting RhoA signaling. However, the effect of extracellular Hsp90α (eHsp90α) on the bronchial epithelial barrier disruption induced by HDM has never been reported. Methods To investigate the involvement of eHsp90α in the bronchial epithelial barrier disruption induced by HDM, normal human bronchial epithelial cell line 16HBE14o- (16HBE) cells were treated by HDM, human recombinant (hr) Hsp90α and hrHsp90β respectively and pretreated by1G6-D7, a specific anti-secreted Hsp90α monoclonal antibody (mAb). Hsp90α-silencing cells were also constructed. To further evaluate the role of RhoA signaling in this process, cells were pretreated by inhibitors of Rho kinase, GSK429286A and Y27632 2HCl. Transepithelial electrical resistance (TEER) and FITC-dextran flux (FITC-DX) were examined as the epithelial barrier function. Expression and localization of adherens junctional proteins E-cadherin and β-catenin were evaluated by western blotting and immunofluorescence respectively. The level of eHsp90α was investigated by concentration and purification of condition media. RhoA activity was determined by using a Rho G-LISA® RhoA activation assay kitTM biochem kit, and the phosphorylation of myosin light chain (MLC), the downstream signal molecule of RhoA, was assessed by western blotting. Results The epithelial barrier disruption and the loss of adherens junctional proteins E-cadherin and β-catenin in cytomembrane were observed in HDM-treated 16HBE cells, paralleled with the increase of eHsp90α secretion. All of which were rescued in Hsp90α-silencing cells or by pretreating 16HBE cells with 1G6-D7. Also, 1G6-D7 suppressed RhoA activity and MLC phosphorylation induced by HDM. Furthermore, inhibitors of Rho kinase prevented and restored the airway barrier disruption. Consistently, it was hrHsp90α instead of hrHsp90β that promoted barrier dysfunction and activated RhoA/MLC signaling in 16HBE cells. Conclusions The eHsp90α mediates HDM-induced human bronchial epithelial barrier dysfunction by activating RhoA/MLC signaling, suggesting that eHsp90α is a potential therapeutic target for treatment of asthma.
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Affiliation(s)
- Hang-Ming Dong
- Chronic Airways Diseases Laboratory, Department of Respiratory and Critical Care Medicine, NanFang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Yan-Qing Le
- Chronic Airways Diseases Laboratory, Department of Respiratory and Critical Care Medicine, NanFang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Yan-Hong Wang
- Chronic Airways Diseases Laboratory, Department of Respiratory and Critical Care Medicine, NanFang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Hai-Jin Zhao
- Chronic Airways Diseases Laboratory, Department of Respiratory and Critical Care Medicine, NanFang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Chao-Wen Huang
- Chronic Airways Diseases Laboratory, Department of Respiratory and Critical Care Medicine, NanFang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Ya-Hui Hu
- Chronic Airways Diseases Laboratory, Department of Respiratory and Critical Care Medicine, NanFang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Li-Shan Luo
- Chronic Airways Diseases Laboratory, Department of Respiratory and Critical Care Medicine, NanFang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Xuan Wan
- Chronic Airways Diseases Laboratory, Department of Respiratory and Critical Care Medicine, NanFang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Yi-Lan Wei
- Chronic Airways Diseases Laboratory, Department of Respiratory and Critical Care Medicine, NanFang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Zi-Qiang Chu
- Chronic Airways Diseases Laboratory, Department of Respiratory and Critical Care Medicine, NanFang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Wei Li
- Department of Dermatology and the Norris Comprehensive Cancer Centre, University of Southern California Keck, Medical Centre, Los Angeles, CA, 90033, USA
| | - Shao-Xi Cai
- Chronic Airways Diseases Laboratory, Department of Respiratory and Critical Care Medicine, NanFang Hospital, Southern Medical University, Guangzhou, 510515, China.
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Taylor M, Carr T, Oke O, Jaunky T, Breheny D, Lowe F, Gaça M. E-cigarette aerosols induce lower oxidative stress in vitro when compared to tobacco smoke. Toxicol Mech Methods 2016; 26:465-476. [PMID: 27690198 DOI: 10.1080/15376516.2016.1222473] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 08/05/2016] [Accepted: 08/05/2016] [Indexed: 01/07/2023]
Abstract
Tobacco smoking is a risk factor for various diseases. The underlying cellular mechanisms are not fully characterized, but include oxidative stress, apoptosis, and necrosis. Electronic-cigarettes (e-cigarettes) have emerged as an alternative to and a possible means to reduce harm from tobacco smoking. E-cigarette vapor contains significantly lower levels of toxicants than cigarette smoke, but standardized methods to assess cellular responses to exposure are not well established. We investigated whether an in vitro model of the airway epithelium (human bronchial epithelial cells) and commercially available assays could differentiate cellular stress responses to aqueous aerosol extracts (AqE) generated from cigarette smoke and e-cigarette aerosols. After exposure to AqE concentrations of 0.063-0.500 puffs/mL, we measured the intracellular glutathione ratio (GSH:GSSG), intracellular generation of oxidant species, and activation of the nuclear factor erythroid-related factor 2 (Nrf2)-controlled antioxidant response elements (ARE) to characterize oxidative stress. Apoptotic and necrotic responses were characterized by increases in caspase 3/7 activity and reductions in viable cell protease activities. Concentration-dependent responses indicative of oxidative stress were obtained for all endpoints following exposure to cigarette smoke AqE: intracellular generation of oxidant species increased by up to 83%, GSH:GSSG reduced by 98.6% and transcriptional activation of ARE increased by up to 335%. Caspase 3/7 activity was increased by up to 37% and the viable cell population declined by up to 76%. No cellular stress responses were detected following exposure to e-cigarette AqE. The methods used were suitably sensitive to be employed for comparative studies of tobacco and nicotine products.
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Affiliation(s)
- Mark Taylor
- a Research and Development Center, British American Tobacco Plc , Southampton , UK
| | - Tony Carr
- a Research and Development Center, British American Tobacco Plc , Southampton , UK
| | - Oluwatobiloba Oke
- a Research and Development Center, British American Tobacco Plc , Southampton , UK
| | - Tomasz Jaunky
- a Research and Development Center, British American Tobacco Plc , Southampton , UK
| | - Damien Breheny
- a Research and Development Center, British American Tobacco Plc , Southampton , UK
| | - Frazer Lowe
- a Research and Development Center, British American Tobacco Plc , Southampton , UK
| | - Marianna Gaça
- a Research and Development Center, British American Tobacco Plc , Southampton , UK
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