低温降低支气管上皮细胞中闭合蛋白的表达：在冷诱导哮喘中的意义。

Low temperature reduces occludin expression in bronchial epithelial cells: Implications in cold-induced asthma.

机构信息

State Key Laboratory of Respiratory Disease, Department of Otolaryngology, Head & Neck Surgery, Laboratory of ENT-HNS Disease, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Department of Allergy and Clinical Immunology, The First Affiliated Hospital, Guangzhou Medical University, Guangzhou, China; Research Center of Allergy & Immunology, Shenzhen University School of Medicine, Shenzhen, China.

出版信息

Mol Immunol. 2023 May;157:176-185. doi: 10.1016/j.molimm.2023.03.018. Epub 2023 Apr 10.

DOI:10.1016/j.molimm.2023.03.018

PMID:37044043

Abstract

BACKGROUND

Cold exposure is a common factor to trigger asthma attacks. However, the underlying mechanism has not been thoroughly elucidated. We aimed to investigate the hypothesis that low temperature reduces occludin expression and compromises epithelial barrier function in airways, which in turn, results in asthma exacerbation.

METHODS

We examined occludin expression in human bronchial epithelial cell line (Beas-2B) cells exposed to either 29 °C or 37 °C. The following drugs were administered prior to cold treatment: MG132 (a proteasome inhibitor), cycloheximide (a protein synthesis inhibitor), HC-067047 plus GSK2193874 (transient receptor potential vanilloid 4 [TRPV4] antagonists), or C4-ceramide (a glucocorticoid-inducible kinase [SGK1] activator). siNedd4-2 was transfected into Beas-2B cells to investigate the role that Nedd4-2 plays in mediating occludin instability induced by cold. In animal experiments, we treated ovalbumin (OVA)-induced asthmatic mice with a thermoneutral temperature of 30 °C or cold exposure (10 °C, 6 h/day) for 2 weeks. GSK2193874 or C4-ceramide was administered during the cold treatment. Occludin expression of the lung, pulmonary permeability, serum IgE levels, and lung inflammation were assessed.

RESULTS

Low temperature treatment (29 °C) significantly reduced the expression of occludin in Beas-2B cells from 1 to 9 h, which was rescued upon treatment with MG132, HC-067047 plus GSK2193874, C4-ceramide, or Nedd4-2 knockdown. Low temperatures affected occludin stability through SGK1/Nedd4-2-dependent proteolysis. In vivo mice data revealed that cold exposure compromised the airway epithelial barrier function, decreased occludin expression, and exacerbated lung inflammation, which was attenuated by the GSK2193874 or C4-ceramide injection.

CONCLUSION

We identified a potential mechanism underlying cold-induced asthma exacerbation involving Nedd4-2-mediated occludin proteolysis and airway epithelial barrier disruption.

摘要

背景

冷暴露是诱发哮喘发作的常见因素。然而，其潜在机制尚未得到充分阐明。我们旨在研究以下假说，即低温降低气道中的紧密连接蛋白表达并损害上皮屏障功能，进而导致哮喘恶化。

方法

我们检测了在 29°C 或 37°C 下暴露的人支气管上皮细胞系（Beas-2B）细胞中的紧密连接蛋白表达。在冷处理之前给予以下药物：MG132（蛋白酶体抑制剂）、环己酰亚胺（蛋白质合成抑制剂）、HC-067047 加 GSK2193874（瞬时受体电位香草酸 4 [TRPV4] 拮抗剂）或 C4-神经酰胺（糖皮质激素诱导的激酶 [SGK1] 激活剂）。转染 siNedd4-2 进入 Beas-2B 细胞，以研究 Nedd4-2 在介导冷诱导的紧密连接蛋白不稳定中所起的作用。在动物实验中，我们用 30°C 的热中性温度或冷暴露（10°C，6h/d）处理卵清蛋白（OVA）诱导的哮喘小鼠 2 周。在冷处理期间给予 GSK2193874 或 C4-神经酰胺。评估肺中的紧密连接蛋白表达、肺通透性、血清 IgE 水平和肺炎症。

结果

低温处理（29°C）在 1 至 9 小时内显著降低 Beas-2B 细胞中紧密连接蛋白的表达，用 MG132、HC-067047 加 GSK2193874、C4-神经酰胺或 Nedd4-2 敲低处理后可恢复。低温通过 SGK1/Nedd4-2 依赖性蛋白水解作用影响紧密连接蛋白的稳定性。体内小鼠数据显示，冷暴露损害气道上皮屏障功能，降低紧密连接蛋白表达，加重肺部炎症，用 GSK2193874 或 C4-神经酰胺注射可减轻这些炎症。