Incense smoke-induced oxidative stress disrupts tight junctions and bronchial epithelial barrier integrity and induces airway hyperresponsiveness in mouse lungs

Norio Yamamoto,Tomohiro Ogawa,Seiji Shinozaki,Miyoko Tatsuta,Keiko Kan-O,Koichiro Matsumoto,Satoru Fukuyama,Yoichi Nakanishi,Yumiko Ishii

doi:10.1038/s41598-021-86745-7

Norio Yamamoto, Tomohiro Ogawa + Show 7 more

Open Access

https://doi.org/10.1038/s41598-021-86745-7

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Abstract

Recent clinical studies have suggested that inhalation of incense smoke (IS) may result in impaired lung function and asthma. However, there is little experimental evidence to link IS with airway hyperresponsiveness (AHR) and bronchial epithelial barrier function. Using mouse and cell culture models, we evaluated the effects of IS exposure on AHR, expression of multiple epithelial tight junction (TJ)- and adherens junction-associated mRNAs and proteins in the lungs, and the barrier function of bronchial epithelial cells assessed by transepithelial electronic resistance (TEER). Exposure of BALB/c mice to IS increased AHR and inflammatory macrophage recruitment to BALF; reduced claudin-1, -2, -3, -7, -10b, -12, -15, and -18, occludin, zonula occludens-1 [ZO-1], and E-cadherin mRNA expression; and caused discontinuity of claudin-2 and ZO-1 protein immunostaining in lung tissue. IS extract dose-dependently decreased TEER and increased reactive oxygen species production in bronchial epithelial cell cultures. Treatment with N-acetyl-l-cysteine, but not glucocorticosteroids or long-acting β2-agonists, prevented the detrimental effects of IS. IS exposure can be problematic for respiratory health, as evidenced by AHR, increased recruitment of inflammatory macrophages and disruption of TJ proteins in the lung, and damage to epithelial barrier function. However, antioxidants may be useful for the treatment of IS-induced airway dysfunction.

Highlights

Recent clinical studies have suggested that inhalation of incense smoke (IS) may result in impaired lung function and asthma
We evaluated the effect of a single exposure of mice to IS on airway hyperresponsiveness (AHR), inflammation and multiple tight junction (TJ) and adherens junctions (AJs)-associated protein expression in the lung, and we analysed the effect of exposure to IS extract (ISE) on epithelial barrier function in human bronchial epithelial cells in air–liquid interface (ALI) cultures
To determine the effects of a single exposure period to IS on airway function, groups of mice were exposed to fresh air or high or low doses of IS for 1 h, and AHR, recruitment of inflammatory cells to bronchoalveolar lavage fluid (BALF), and apoptosis of lung cells were assessed over the following 24 h

Summary

Introduction

Recent clinical studies have suggested that inhalation of incense smoke (IS) may result in impaired lung function and asthma. Using mouse and cell culture models, we evaluated the effects of IS exposure on AHR, expression of multiple epithelial tight junction (TJ)- and adherens junction-associated mRNAs and proteins in the lungs, and the barrier function of bronchial epithelial cells assessed by transepithelial electronic resistance (TEER). We recently reported that exposure of human bronchial epithelial cells to cigarette smoke in vitro disrupted epithelial barrier function and simultaneously downregulated the expression of multiple TJ and AJassociated proteins[13]. We evaluated the effect of a single exposure of mice to IS on airway hyperresponsiveness (AHR), inflammation and multiple TJ and AJ-associated protein expression in the lung, and we analysed the effect of exposure to IS extract (ISE) on epithelial barrier function in human bronchial epithelial cells in air–liquid interface (ALI) cultures. We investigated whether treatment with GCSs, LABAs, or the antioxidant N-acetyl-l-cysteine (NAC) could protect against IS-induced airway dysfunction in vitro and in vivo

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