Department of Public Health and Primary Care, Centre for Environment and Health, 26657KU Leuven, Leuven, Belgium.
Man-Technology-Environment Research Centre, 6233Örebro University, Örebro, Sweden.
Toxicol Ind Health. 2020 Oct;36(10):823-834. doi: 10.1177/0748233720948771. Epub 2020 Aug 25.
The airway epithelium is continuously exposed to environmental irritants, which can cause adverse effects such as irritant-induced asthma (IIA). Mast cells are located near airway epithelia and are able to respond to a variety of stimuli. We aimed to investigate whether mast cells influence the response of the epithelium upon irritant exposure. Two cell lines and three different seeding conditions, that is, bronchial epithelial cells (16HBE) only, 16HBE with mast cells (HMC-1's) basolaterally, and 16HBE with HMC-1's apically, were established. Upon exposure to the environmental irritants, graphene (G), graphene oxide (GO), diesel exhaust particles (DEPs) or hypochlorite (ClO), transepithelial electrical resistance (TEER) and paracellular flux of fluorescent-labeled dextrans were determined, along with the release of mediators. Identical experiments were conducted with the Ca ionophore ionomycin. Exposure to G and GO induced a significant and permanent decrease of approximately 70% in TEER after 3 h of exposure, whereas DEP and ClO exposure resulted in a transient decrease of approximately 20% in TEER. This response pattern was similar in all the different seeding conditions. After 24 h of exposure, fluorescein isothiocyanate-dextran transport was 10-fold greater for G and 5-fold greater for GO in each of the tested seeding conditions, while DEP and ClO induced no change compared to the control. Upon exposure to the irritants, 16HBE did not release thymic stromal lymphopoietin, interleukin 33 (IL-33), or IL-1α, and HMC-1 cells did not release histamine, IL-6, or IL-8. Epithelial barrier integrity upon treatment with ionomycin was not affected by the presence of HMC-1 cells. A limited amount of IL-6 and IL-8 was released by ionomycin-exposed HMC-1 cells. To conclude, we found that the studied environmental irritants do not directly or indirectly activate HMC-1 cells. These mast cells did not influence the epithelial barrier function upon environmental exposure, and thus currently do not provide additional information for the underlying mechanism of IIA.
气道上皮细胞不断暴露于环境刺激物中，这可能会导致不良影响，如刺激诱导性哮喘（IIA）。肥大细胞位于气道上皮附近，能够对各种刺激做出反应。我们旨在研究肥大细胞是否会影响上皮细胞在受到刺激物暴露时的反应。我们建立了两种细胞系和三种不同的接种条件，即仅支气管上皮细胞（16HBE）、基底外侧有肥大细胞（HMC-1）的 16HBE 和顶部有 HMC-1 的 16HBE。在暴露于环境刺激物石墨烯（G）、氧化石墨烯（GO）、柴油 exhaust particles (DEPs) 或次氯酸盐 (ClO) 后，测定了跨上皮电阻（TEER）和荧光标记葡聚糖的旁细胞通量，以及介质的释放。用钙离子载体离子霉素进行了相同的实验。暴露于 G 和 GO 会导致 TEER 在暴露 3 小时后显著且永久性地降低约 70%，而 DEP 和 ClO 暴露会导致 TEER 短暂降低约 20%。这种反应模式在所有不同的接种条件下都相似。暴露 24 小时后，在每种测试的接种条件下，G 和 GO 使荧光素异硫氰酸酯-葡聚糖的转运增加了 10 倍和 5 倍，而 DEP 和 ClO 与对照相比没有变化。暴露于刺激物后，16HBE 没有释放胸腺基质淋巴细胞生成素、白细胞介素 33 (IL-33) 或白细胞介素 1α，而肥大细胞没有释放组氨酸、白细胞介素 6 (IL-6) 或白细胞介素 8 (IL-8)。离子霉素处理时上皮屏障完整性不受肥大细胞存在的影响。离子霉素暴露的肥大细胞释放有限量的白细胞介素 6 和白细胞介素 8。总之，我们发现研究中的环境刺激物不会直接或间接激活肥大细胞。这些肥大细胞在暴露于环境刺激物时不会影响上皮屏障功能，因此目前不会为 IIA 的潜在机制提供额外信息。
