Reactive oxygen species are required for maintenance and differentiation of primary lung fibroblasts in idiopathic pulmonary fibrosis

• Published in: PloS one 2010-11, Vol.5 (11), p.e14003
• Main Authors: Bocchino, Marialuisa, Agnese, Savina, Fagone, Evelina, Svegliati, Silvia, Grieco, Domenico, Vancheri, Carlo, Gabrielli, Armando, Sanduzzi, Alessandro, Avvedimento, Enrico V
• Format: Article
• Language: English
• Subjects: Acetylcysteine - pharmacology; Actin; Actins - metabolism; Analysis; Animal models; Apoptosis; Blotting, Western; Cell activation; Cell culture; Cell death; Cell Differentiation; Cell Survival - drug effects; Cells, Cultured; Collagen; Collagen Type I - metabolism; Differentiation; Dose-Response Relationship, Drug; Extracellular Signal-Regulated MAP Kinases - metabolism; Fibroblasts; Fibroblasts - drug effects; Fibroblasts - metabolism; Fibrosis; Free Radical Scavengers - pharmacology; Genotype & phenotype; Growth factors; Growth rate; Histology; Humans; Hydrogen Peroxide - pharmacology; Idiopathic Pulmonary Fibrosis - metabolism; Idiopathic Pulmonary Fibrosis - pathology; Lung diseases; Lungs; Mass spectrometry; Medical research; Middle Aged; Molecular modelling; Muscle proteins; Muscle, Smooth - chemistry; NAD(P)H oxidase; Oxidants - pharmacology; Oxidases; Oxidation resistance; Oxidative stress; Oxygen; Pathogenesis; Patients; Phosphorylation; Protein-tyrosine kinase; Protein-Tyrosine Kinases - metabolism; Proteins; Pulmonary fibrosis; Reactive oxygen species; Reactive Oxygen Species - antagonists & inhibitors; Reactive Oxygen Species - metabolism; Redox properties; Respiratory Medicine; Respiratory Medicine/Interstitial Lung Diseases; Respiratory Medicine/Respiratory Infections; Reverse Transcriptase Polymerase Chain Reaction; Rodents; Scientific imaging; Signal transduction; Signaling; Smooth muscle; Stress concentration; Transforming Growth Factor beta1 - genetics; Transforming Growth Factor beta1 - metabolism; Tyrosine
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0014003

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal illness whose pathogenesis remains poorly understood. Recent evidence suggests oxidative stress as a key player in the establishment/progression of lung fibrosis in animal models and possibly in human IPF. The aim of the present study was to characterize the cellular phenotype of fibroblasts derived from IPF patients and identify underlying molecular mechanisms. We first analyzed the baseline differentiation features and growth ability of primary lung fibroblasts derived from 7 histology proven IPF patients and 4 control subjects at different culture passages. Then, we focused on the redox state and related molecular pathways of IPF fibroblasts and investigated the impact of oxidative stress in the establishment of the IPF phenotype. IPF fibroblasts were differentiated into alpha-smooth muscle actin (SMA)-positive myofibroblasts, displayed a pro-fibrotic phenotype as expressing type-I collagen, and proliferated lower than controls cells. The IPF phenotype was inducible upon oxidative stress in control cells and was sensitive to ROS scavenging. IPF fibroblasts also contained large excess of reactive oxygen species (ROS) due to the activation of an NADPH oxidase-like system, displayed higher levels of tyrosine phosphorylated proteins and were more resistant to oxidative-stress induced cell death. Interestingly, the IPF traits disappeared with time in culture, indicating a transient effect of the initial trigger. Robust expression of α-SMA and type-I collagen, high and uniformly-distributed ROS levels, resistance to oxidative-stress induced cell death and constitutive activation of tyrosine kinase(s) signalling are distinctive features of the IPF phenotype. We suggest that this phenotype can be used as a model to identify the initial trigger of IPF.