Abstract Background/Aims: Epoxyeicosatrienoic acids (EETs) are metabolic products of free arachidonic acid (AA). EETs have anti-inflammatory activities. However, the effect of EETs on cigarette smoke-induced lung inflammation is not clear. Autophagy is believed to be involved in the pathogenesis of COPD. In addition, nuclear erythroid-related factor 2 (Nrf2), is thought to regulate antioxidant defenses in several lung diseases. Besides, interaction between EETs, autophagy and Nrf2 has been reported. The aim of this study was to explore the effect of 14, 15-EET on cigarette smoke condensate (CSC)-induced inflammation in human bronchial epithelial cell line (Beas-2B), and to determine the underlying mechanisms. Methods: Autophagy and its signaling pathway proteins, LC3B, p62, PI3K, AKT, p-AKT, p-mTOR, anti-inflammatory proteins Nrf2, HO-1 were assessed on Western blot analysis. Autophagosomes and autolysosomes were detected by Ad- mRFP-GFP-LC3 transfection. Inflammatory factors (IL-6, IL-8 and MCP-1) were detected by ELISA. Lentiviral vectors carrying p62 shRNA were used to interfere with the expression of p62 to evaluate the effect of p62 on Nrf2 expression. Nrf2 expression was determined on immunocytochemistry. Results: 14, 15-EET significantly reduced the secretion IL-6, IL-8 and MCP-1, and increased Nrf2 and HO-1. In addition, 14, 15-EET inhibited CSC-induced autophagy in Beas-2B cells. The mechanism of anti-inflammatory effect of 14, 15-EET involved inhibition of autophagy and increase in p62 levels, followed by translocation of Nrf2 into the nucleus and upregulated the expression of HO-1. Conclusion: 14, 15-EET protects against CSC-induced lung inflammation by promoting the accumulation of Nrf2 via through inhibition of autophagy.
- epoxyeicosatrienoic acids
- cigarette smoke
- Copyright © 2016, American Journal of Physiology-Lung Cellular and Molecular Physiology