Alpha1-Antitrypsin reduces endoplasmic reticulum stress, inflammatory cytokines and improves wound repair in alveolar epithelial cells of fibrotic lung in vitro

Dysregulation of endoplasmic reticulum (ER stress) has been reported in IPF patients. ER stress leads to improper wound healing and unfolded protein response. Chronic inflammation, exacerbation and progressive lung destruction are characteristics of IPF leading to a protease/anti-protease imbalance. Therefore, use of specific inhibitor of neutrophil elastase Alpha1-Antitrypsin (AAT) may be a promising approach in IPF. We investigate the effect of AAT on ER stress in IPF. AEC from IPF lung were treated with various concentration of AAT, supernatant was evaluated for IL-6, IL-8, TGF-β and mRNA for ER stress markers: GRP78, spliced XBP-1 andCHOP. For wound healing experiments A549 and B2B cell lines were treated with different concentrations of AAT in a standard scratch assay test in vitro. AEC from IPF patients are under ER stress. AAT significantly inhibits ER stress induction at mRNA level of Grp78 (1.95±0.15) vs control (5.85±0.05), and CHOP (0.93±0.04) vs control (3.75±0.32) but not in spliced XBP-1 form in the IPF primary cells. Cytokine release of pro-inflammatory and pro-fibrotic marker: IL-6 (142.1±5.28) vs (386.2±107.0) in control, IL-8 (273.3±43.12) vs (614.6±103.3) in control and TGF-β (26.31±0.30) vs (68.53±1.83) in control, were abolished by treatment with AAT. We observed improved wound repair in human alveolar epithelial A549 and human bronchial epithelial B2B cell line in response to AAT treatment in our scratch assay. AEC from IPF patients are under ER stress. ER stress pathways may serve as important therapeutic targets in IPF. AAT reduces ER stress pro-inflammatory and pro-fibrotic mediators in primary AEC.