Department of Pediatric Respiratory Medicine, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China.
Institute for Pediatric Research, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China.
Inflammation. 2018 Aug;41(4):1266-1275. doi: 10.1007/s10753-018-0774-y.
Bronchial asthma is a chronic inflammatory airway disease that can be aggravated by cold air. However, its mechanism remains largely unknown. As a thermo-sensing cation channel, transient receptor potential melastatin 8 (TRPM8) can be activated by cold stimuli (8-22 °C) and cooling agents. Whereas TRPM8 activation leads to enhanced expression of inflammatory cytokines and mucus hypersecretion in human bronchial epithelial cell lines, no previous study has examined its role in regulating the cold-induced inflammatory responses and its mechanism in asthmatic airway epithelium. Airway epithelial cells were isolated from asthma model mice and exposed to low temperature (18 °C). The TRPM8 overexpression plasmid and siRNA lentivirus were transfected to up- or downregulate the TRPM8 level. The expression of mRNAs of inflammatory cytokines was tested using real-time reverse transcription-polymerase chain reaction (RT-PCR). The activities of phosphorylated protein kinase C (PKC) and phosphorylated inhibitor of nuclear factor kappa B (IκB) were measured using the immunofluorescence assay. The expression of mRNAs of inflammatory cytokines [interleukin (IL)-1β, IL-4, IL-6, IL-8, IL-10, IL-13, granulocyte macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor (TNF)-α] increased significantly under cold conditions, which was boosted after TRPM8 overexpression and augmented further in the presence of PKC inhibitor, calphostin C. However, the downregulation of TRPM8 and nuclear factor kappa B (NF-κB) impaired the transcription of these cytokine genes. In addition, the phosphorylated PKC and phosphorylated IκB were activated by cold stimuli. Moreover, the expression of phosphorylated IκB protein improved in the presence of TRPM8, while disruption with the TRPM8 gene or TRPM8 antagonist prohibited the activation of IκB. Cold air could induce inflammatory responses through the TRPM8-mediated PKC/NF-κB signal pathway in primary airway epithelial cells of asthmatic mice.
支气管哮喘是一种慢性炎症性气道疾病，可因冷空气而加重。然而，其机制在很大程度上仍不清楚。作为一种热敏阳离子通道，瞬时受体电位 melastatin 8（TRPM8）可被冷刺激（8-22°C）和冷却剂激活。然而，TRPM8 的激活导致人支气管上皮细胞系中炎症细胞因子表达增强和黏液过度分泌，以前没有研究检查过它在调节冷诱导的炎症反应及其在哮喘气道上皮中的机制中的作用。从哮喘模型小鼠中分离气道上皮细胞并暴露于低温（18°C）下。用 TRPM8 过表达质粒和 siRNA 慢病毒转染以上调或下调 TRPM8 水平。使用实时逆转录聚合酶链反应（RT-PCR）测试炎症细胞因子的 mRNA 表达。使用免疫荧光测定法测量磷酸化蛋白激酶 C（PKC）和磷酸化核因子 kappa B（IκB）的活性。在冷条件下，炎症细胞因子[白细胞介素（IL）-1β、IL-4、IL-6、IL-8、IL-10、IL-13、粒细胞-巨噬细胞集落刺激因子（GM-CSF）和肿瘤坏死因子（TNF）-α]的 mRNA 表达显著增加，TRPM8 过表达后增强，PKC 抑制剂 calphostin C 存在时进一步增强。然而，TRPM8 和核因子 kappa B（NF-κB）的下调削弱了这些细胞因子基因的转录。此外，冷刺激激活了磷酸化 PKC 和磷酸化 IκB。此外，TRPM8 的存在可改善磷酸化 IκB 蛋白的表达，而 TRPM8 基因或 TRPM8 拮抗剂的破坏可阻止 IκB 的激活。冷空气可通过哮喘小鼠原代气道上皮细胞中的 TRPM8 介导的 PKC/NF-κB 信号通路诱导炎症反应。
