Lung Epithelial TRPA1 Transduces the Extracellular ROS into Transcriptional Regulation of Lung Inflammation Induced by Cigarette Smoke: The Role of Influxed Ca²⁺

Figure 9

The proposed mechanism of TRPA1 activation for the induction of IL-8 by cigarette smoke (CS). As shown, exposure to CS initially causes an increase in the extracellular level of reactive oxygen species (ROS), which in turn activates lung epithelial TRPA1; this leads to the promotion of a Ca²⁺ influx. The increase in the intracellular level of Ca²⁺ in lung epithelial cells then contributes to the activation of NADPH oxidase, which in turn results in an elevation of the intracellular level of ROS and this then activates the mitogen-activated protein kinases (MAPKs)/nuclear factor-κB (NF-κB) signaling pathway allowing induction of IL-8.