Kim Joo-Hee, Jang Young-Sook, Jang Seung-Hun, Jung Ki-Suck, Kim Seung-Hyun, Ye Young-Min, Park Hae-Sim
Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, South Korea.
Department of Allergy and Clinical Immunology, Ajou Research Institute for Innovation Medicine, Ajou University Medical Center, Suwon, South Korea.
Exp Mol Med. 2017 Mar 3;49(3):e299. doi: 10.1038/emm.2016.161.
Toluene diisocyanate (TDI) is the most important cause of occupational asthma (OA), and various pathogenic mechanisms have been suggested. Of these mechanisms, neurogenic inflammation is an important inducer of airway inflammation. Transient receptor potential melastatin 8 (TRPM8) is a well-established cold-sensing cation channel that is expressed in both neuronal cells and bronchial epithelial cells. A recent genome-wide association study of TDI-exposed workers found a significant association between the phenotype of TDI-induced OA and the single-nucleotide polymorphism rs10803666, which has been mapped to the TRPM8 gene. We hypothesized that TRPM8 located in airway epithelial cells may be involved in the pathogenic mechanisms of TDI-induced OA and investigated its role. Bronchial epithelial cells were treated with TDI in a dose- and time-dependent manner. The expression levels of TRPM8 mRNA and protein were determined by quantitative real-time polymerase chain reaction and western blotting. TDI-induced morphological changes in the cells were evaluated by immunocytochemistry. Alterations in the transcripts of inflammatory cytokines were examined in accordance with TRPM8 activation by TDI. TRPM8 expression at both the mRNA and protein levels was enhanced by TDI in airway epithelial cells. TRPM8 activation by TDI led to significant increases in the mRNA of interleukin (IL)-4, IL-13, IL-25 and IL-33. The increased expression of the cytokine genes by TDI was partly attenuated after treatment with a TRPM8 antagonist. TDI exposure induces increased expression of TRPM8 mRNA in airway epithelial cells coupled with enhanced expression of inflammatory cytokines, suggesting a novel role of TRPM8 in the pathogenesis of TDI-induced OA.
甲苯二异氰酸酯（TDI）是职业性哮喘（OA）的最重要病因，人们提出了多种致病机制。在这些机制中，神经源性炎症是气道炎症的重要诱导因素。瞬时受体电位香草酸亚型8（TRPM8）是一种公认的冷敏阳离子通道，在神经元细胞和支气管上皮细胞中均有表达。最近一项针对接触TDI工人的全基因组关联研究发现，TDI诱导的OA表型与单核苷酸多态性rs10803666之间存在显著关联，该多态性已被定位到TRPM8基因。我们推测位于气道上皮细胞中的TRPM8可能参与TDI诱导的OA的致病机制，并对其作用进行了研究。用TDI以剂量和时间依赖性方式处理支气管上皮细胞。通过定量实时聚合酶链反应和蛋白质印迹法测定TRPM8 mRNA和蛋白的表达水平。通过免疫细胞化学评估TDI诱导的细胞形态变化。根据TDI对TRPM8的激活情况，检测炎性细胞因子转录本的变化。TDI可增强气道上皮细胞中TRPM8在mRNA和蛋白水平的表达。TDI对TRPM8的激活导致白细胞介素（IL）-4、IL-13、IL-25和IL-33的mRNA显著增加。在用TRPM8拮抗剂处理后，TDI诱导的细胞因子基因表达增加有所减弱。TDI暴露诱导气道上皮细胞中TRPM8 mRNA表达增加，同时炎性细胞因子表达增强，提示TRPM8在TDI诱导的OA发病机制中具有新作用。
