Regulation and function of the two-pore-domain (K2P) potassium channel Trek-1 in alveolar epithelial cells.
Regulation and function of the two-pore-domain (K2P) potassium channel Trek-1 in alveolar epithelial cells.
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DOI：
10.1152/ajplung.00078.2011
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
A. Schwingshackl;B. Teng;M. Ghosh;A. West;P. Makena;Vijay K. Gorantla;S. Sinclair;C. Waters
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文献类型：
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作者：
A. Schwingshackl;B. Teng;M. Ghosh;A. West;P. Makena;Vijay K. Gorantla;S. Sinclair;C. Waters
高氧可导致肺中的无数有害作用，包括上皮损伤和弥漫性炎症。高氧促进这些病理变化的具体机制尚不完全清楚。离子通道的激活被认为是细胞激活和介质分泌所需的机制之一。最近在肺上皮细胞中描述了双孔结构域K（+）通道（K2 P）Trek-1，但其功能仍然不清楚。在这项研究中，我们假设高氧影响肺泡上皮细胞中Trek-1的表达，Trek-1参与细胞增殖和细胞因子分泌的调节。我们在小鼠肺泡上皮细胞（MLE-12）中发现了几种K2 P通道的基因表达，并且Trek-1的表达在培养的细胞和暴露于高氧的小鼠肺中显著下调。同样，增殖细胞核抗原（PCNA）和细胞周期蛋白D1的表达下调暴露于高氧。我们开发了一个MLE-12细胞系缺乏Trek-1表达的shRNA，发现Trek-1缺陷导致细胞增殖增加和PCNA的上调，但不是细胞周期蛋白D1。此外，IL-6和调节激活正常T表达和推测分泌（RANTES）分泌减少Trek-1缺陷细胞，而单核细胞趋化蛋白-1的释放增加。KC/IL-8的释放不受Trek-1缺陷的影响。总的来说，Trek-1的缺乏对介质分泌的影响比暴露于高氧更明显。这是第一份报告表明，K（+）通道Trek-1可能参与调节肺泡上皮细胞增殖和细胞因子分泌，但与高氧诱导的Trek-1水平变化的直接关联仍然难以捉摸。
Hyperoxia can lead to a myriad of deleterious effects in the lung including epithelial damage and diffuse inflammation. The specific mechanisms by which hyperoxia promotes these pathological changes are not completely understood. Activation of ion channels has been proposed as one of the mechanisms required for cell activation and mediator secretion. The two-pore-domain K(+) channel (K2P) Trek-1 has recently been described in lung epithelial cells, but its function remains elusive. In this study we hypothesized that hyperoxia affects expression of Trek-1 in alveolar epithelial cells and that Trek-1 is involved in regulation of cell proliferation and cytokine secretion. We found gene expression of several K2P channels in mouse alveolar epithelial cells (MLE-12), and expression of Trek-1 was significantly downregulated in cultured cells and lungs of mice exposed to hyperoxia. Similarly, proliferation cell nuclear antigen (PCNA) and Cyclin D1 expression were downregulated by exposure to hyperoxia. We developed an MLE-12 cell line deficient in Trek-1 expression using shRNA and found that Trek-1 deficiency resulted in increased cell proliferation and upregulation of PCNA but not Cyclin D1. Furthermore, IL-6 and regulated on activation normal T-expressed and presumably secreted (RANTES) secretion was decreased in Trek-1-deficient cells, whereas release of monocyte chemoattractant protein-1 was increased. Release of KC/IL-8 was not affected by Trek-1 deficiency. Overall, deficiency of Trek-1 had a more pronounced effect on mediator secretion than exposure to hyperoxia. This is the first report suggesting that the K(+) channel Trek-1 could be involved in regulation of alveolar epithelial cell proliferation and cytokine secretion, but a direct association with hyperoxia-induced changes in Trek-1 levels remains elusive.