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Mechanisms involved in the antioxidant properties of azithromycin in lung epithelial cells stimulated with cigarette smoke extract
Author(s) -
Cuevas Santiago,
Yang Yu,
Armando Ines,
Jose Pedro A
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.982.2
Subject(s) - oxidative stress , a549 cell , antioxidant , chemistry , reactive oxygen species , azithromycin , pharmacology , respiratory epithelium , inflammation , immunology , lung , biochemistry , medicine , antibiotics , cell
Chronic Obstructive Pulmonary Disease (COPD) is a leading cause of mortality world‐wide. Macrolide antibiotics, e.g. azithromycin has antioxidant and anti‐inflammatory properties and decreases the frequency of acute exacerbations of chronic obstructive pulmonary disease (COPD). The aim of this study was to identify the molecular mechanisms whereby azithromycin decreases oxidative stress and inflammation. We have reported that azithromycin decreased intracellular Nrf2 protein level (−55±6%) and downstream phase II detoxifying enzyme NQO1 (−45±4%), reactive oxygen species (ROS) production (−1.6‐fold), and pro‐inflammatory cytokine interleukin 8 (IL‐8) secretion (−2.1‐fold) in A549 cells (human airway epithelial cells) exposed to cigarette smoke extract (CSE) (200 mg/ml, 24 h); new data indicate that histone deacetylase 2 (HDAC2) expression is also decreased (−41±4%). Pretreatment of A549 cells with azithromycin (0.5μg/ml) suppressed ROS production (−29±4%) and IL‐8 (−45±6%) induced by CSE and decreased G protein‐coupled receptor kinase 4 (GRK4) expression (−33%). Furthermore, azithromycin promoted Nrf2 nuclear translocation (270±24%) catalyzing the reduction of hyper‐oxidized peroxiredoxins (Prx) (−70±3%) leading to reduction of oxidative stress. H 2 O 2 (200 mM/24 h) increased GRK4 (191±4%) and decreased, HDAC2 (−29±4%) expressions suggesting that oxidative stress can regulate these proteins. GRK4 co‐localize with surfactant protein A (SP‐A) (marker for alveolar epithelium type II) in human lung tissue and GRK4 and HDAC2 colocalize in human bronchus. Sestrin2, an antioxidant enzyme, was increased after treatment with azithromycin in a time and concentration dependent manner. Knockdown of Nrf2 resulted in suppression of azithromycin‐induced sestrin2 expression (−35±3%). Silencing sestrin2 abolished azithromycin‐induced decrease in peroxiredoxins hyper‐oxidation and partially attenuated the inhibitory effect of azithromycin on ROS production and IL‐8 expression (by 26% and 41%, respectively). Our results suggest that the antioxidant and anti‐inflammatory effects of azithromycin in COPD may be, in part, mediated by induction of sestrin2 via Nrf2, involving the GRK4, and HDAC2 pathways.