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

Figure 4

The CSE-induced extracellular ROS stimulate TRPA1 to Ca²⁺-dependently increase intracellular ROS via NADPH oxidase in HBECs. (a–c) Cells were exposed to medium alone or to 3% CSE for 2, 30, and 15 min, respectively, after pretreatment with apocynin (APO; an inhibitor of NADPH oxidase; 150 μM), after pretreatment with N-acetyl-cysteine (NAC, a ROS scavenger; 1 mM), after pretreatment with HC-030031 (HC, a TRPA1 antagonist; 9 μM), or after pretreatment with EGTA (an extracellular Ca²⁺ chelator; 500 μM). Levels of ROS were measured by HE fluorescent probe assay. NADPH oxidase activity was measured by NADP⁺/NADPH assay. Data in each group are mean ± SEM from five independent experiments. versus the control; ^# versus CSE alone.

(a)

(b)

(c)