BioProject

Idiopathic pulmonary fibrosis (IPF) is a progressive and ultimately fatal interstitial lung disease characterized by alveolar epithelial cell type II (AECII) injury and enhanced fibroblast/myofibroblast proliferation. More...

Idiopathic pulmonary fibrosis (IPF) is a progressive and ultimately fatal interstitial lung disease characterized by alveolar epithelial cell type II (AECII) injury and enhanced fibroblast/myofibroblast proliferation. Recent data show that maladaptive endoplasmic reticulum (ER)-stress leading to AECII apoptosis could play a key role in IPF, although it is still unclear how precisely such response is initiated and signalled. C/EBP homologous protein (CHOP) has been suggested to contribute to a maladaptive ER-stress response in general and has been found to be induced and to be translocated into the nucleus of AECII in IPF in particular. We here show for the first time a novel mechanism for the regulation of CHOP expression during ER-stress in AECII via AP-1 and c-Ets-1. We found these two transcription factors to be up-regulated in AECII under ER-stress conditions and to interact with each other to jointly bind to the CHOP promoter, thereby inducing CHOP gene expression. Moreover, we show for the first time that singular CHOP overexpression in vitro and in vivo is indeed capable of inducing apoptosis of AECII and, consequently, lung fibroblast proliferation and up-regulation of pro-fibrotic markers. We therefore believe that CHOP plays a key role in AEC injury and consecutive fibrosis. Overall design: Cell-culture of MLE12 cells, transfected and/or treated with Thapsigargin (TG, 1µM/ml), dual-color hybridizations (always two similar samples were labelled with Cy3 and Cy5 and hybridized on one array). Less...