A new function of aquaporin provide a insight into the molecular mechanism to inhibit inflammatory response

水通道蛋白5 （Aquaporin-5, AQP5）表达于支气管浆液细胞和外分泌腺，在气道水分平衡中起重要作用。在本研究中，我们研究了AQP5在炎症反应中的作用。AQP5在各种细胞中的过表达增加了细胞因子的表达，磷酸化的ERK水平稳定，NF-kappaB活性增加。因此，我们认为ERK和NF-kappaB对AQP5的这一新功能很重要。此外，AQP1和AQP5 c端转化为AQP1的AQP5- 1ct嵌合体均未能增加细胞因子的表达，提示AQP5 c端对炎症反应的增加有重要作用。最后，我们发现肉桂提取物可以抑制ERK磷酸化和AQP5细胞因子的表达。综上所述，我们提出了AQP5作为细胞因子信号增强因子的新功能，肉桂可能有助于控制AQP5表达细胞的炎症反应。

Aquaporin-5 (AQP5) is expressed in bronchial serous cells and exocrine gland, plays an important role for water homeostasis in airway. In the present study, we have examined the role of AQP5 for inflammatory response. Overexpression of AQP5 to various cells increased cytokine expression, steady level of phosphorylated ERK, and activity of NF-kappaB. Therefore, we assume that ERK and NF-kappaB are important for this new function of AQP5. Further, both AQP1 and AQP5-1CT chimera, which is converted C-terminal of AQP5 to AQP1, failed to increase cytokine expression, suggesting C-terminal of AQP5 is important for increased inflammatory response. Finally, we found extract of cinnamon as an inhibitor of ERK phosphorylation and cytokine expression by AQP5. Take together, we propose a new function of AQP5, as a cytokine signal enhancer, and cinnamon may be useful to control inflammatory response in AQP5 expressing cells.