Senescence intensifies bleomycin-induced injury in idiopathic pulmonary fibrosis lung epithelial cells

Introduction Idiopathic pulmonary fibrosis (IPF) is a lethal lung disease involving injury and a dysregulated repair response of an ageing epithelium. Here we investigate the contribution of senescence and telomere shortening to bleomycin-induced injury in alveolar epithelial cells (EpCs) derived from lung parenchymal tissue of patients with pulmonary fibrosis (PF), predominantly IPF, in vitro . Methods Injury responses of EpCs in air–liquid interface (ALI) culture were assessed by ELISA, qPCR and/or immunofluorescence at 48 and 96 h post-bleomycin (30 μg·mL −1 ) treatment. Telomere length was evaluated by qPCR and corroborated by fluorescence in situ hybridisation. Results Bleomycin treatment increased markers of inflammation ( i.e. interleukin (IL)-6 and IL-36γ) and senescence ( i.e. p16 and p21) in EpCs from PF patients (PF EpCs) (p