Abstract
Objectives: Cigarette smoke is known to cause inflammatory response in human bronchial epithelial cells. In this study, we investigated the effects of quercetin, a flavonoid abundant in fruits and vegetables, on cigarette smoke extract (CSE)-induced inflammation in human bronchial epithelial cells (HBEC) and roles of autophagy in this process.
Methods: HBEC were exposed to CSE (4%) for 24h, with or without pretreatment of quercetin (10μM or 20μM). The autophagy activation marker, LC3 II protein, was detected with western blotting. Autophagy was inhibited by 3-methyladenine (3-MA) (2.5mM). TNF-α and IL-1β levels in the supernatant were determined by ELISA.
Results: Exposure of HBEC to CSE significantly increased TNF-α and IL-1β expression and this upregulaion was significantly attenuated by quercetin (p<0.05). Meanwhile, the pre-treatment of quercetin decreased the ratio of LC3 II to LC3 I, which was increased by CSE (p<0.05). Inhibiting autophagy by 3-MA also decreased TNF-α and IL-1β levels to a similar level as that of quercetin.
Conclusion: These results suggest that quercetin attenuated inflammation induced by cigarette smoke. The anti- inflammatory effect might act through modulating autophagy.
- © 2013 ERS