Functional expression of the transient receptor potential channel TRPA1, a sensor for toxic lung inhalants, in pulmonary epithelial cells
Functional expression of the transient receptor potential channel TRPA1, a sensor for toxic lung inhalants, in pulmonary epithelial cells
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DOI：
10.1016/j.cbi.2013.08.012
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发表时间：
2013-12-05
影响因子：
5.1
通讯作者：
Schmidt, Annette
中科院分区：
文献类型：
--
作者：
Buech, Thomas Robert Heinrich;Schaefer, Eva Anna Maria;Schmidt, Annette
阳离子通道TRPA 1作为一种化学感受蛋白发挥作用，并被许多有毒吸入物直接激活。TRPA 1的肺部表达已被描述在感觉神经末梢中，并且其刺激导致肺部炎症反应的加速。尽管TRPA 1在神经元细胞中的功能已被明确定义，但只有少数报告表明其在上皮细胞中的作用。因此，本研究的目的是（1）评估肺上皮细胞系中TRPA 1的表达，（2）表征这些细胞中TRPA 1促进的信号传导，以及（3）研究肺组织切片中该通道的神经元外表达。我们的研究结果表明，广泛使用的肺泡II型细胞系A549表达TRPA 1在mRNA和蛋白水平。此外，用已知的TRPA 1激活剂（即，异硫氰酸烯丙酯）导致细胞内钙水平增加，这对TRPA 1阻断剂钌红敏感。研究TRPA 1偶联的下游信号级联，发现TRPA 1激活引起ERK 1/2的刺激，而其他MAP激酶不受影响。最后，在免疫组织化学方法中使用上皮和神经元标记物，在猪肺上皮的远端部分检测到非神经元TRPA 1蛋白表达，这也在检查人肺切片时发现。TRPA 1阳性染色与上皮和神经元标记物共定位，强调观察到的上皮表达模式。我们的研究结果TRPA 1在肺上皮细胞中的功能性表达提供了因果关系的证据，非神经元TRPA 1介导的控制炎症反应引起的TRPA 1介导的登记有毒吸入剂在体内。(C)2013爱思唯尔爱尔兰有限公司版权所有。
The cation channel TRPA1 functions as a chemosensory protein and is directly activated by a number of noxious inhalants. A pulmonary expression of TRPA1 has been described in sensory nerve endings and its stimulation leads to the acceleration of inflammatory responses in the lung. Whereas the function of TRPA1 in neuronal cells is well defined, only few reports exist suggesting a role in epithelial cells. The aim of the present study was therefore (1) to evaluate the expression of TRPA1 in pulmonary epithelial cell lines, (2) to characterize TRPA1-promoted signaling in these cells, and (3) to study the extra-neuronal expression of this channel in lung tissue sections. Our results revealed that the widely used alveolar type II cell line A549 expresses TRPA1 at the mRNA and protein level. Furthermore, stimulating A549 cells with known TRPA1 activators (i.e., allyl isothiocyanate) led to an increase in intracellular calcium levels, which was sensitive to the TRPA1 blocker ruthenium red. Investigating TRPA1 coupled downstream signaling cascades it was found that TRPA1 activation elicited a stimulation of ERK1/2 whereas other MAP kinases were not affected. Finally, using epithelial as well as neuronal markers in immunohistochemical approaches, a non-neuronal TRPA1 protein expression was detected in distal parts of the porcine lung epithelium, which was also found examining human lung sections. TRPA1-positive staining co-localized with both epithelial and neuronal markers underlining the observed epithelial expression pattern. Our findings of a functional expression of TRPA1 in pulmonary epithelial cells provide causal evidence for a non-neuronal TRPA1-mediated control of inflammatory responses elicited upon TRPA1-mediated registration of toxic inhalants in vivo. (C) 2013 Elsevier Ireland Ltd. All rights reserved.