title: Reactive oxygen species are required for maintenance and differentiation of primary lung fibroblasts in idiopathic pulmonary fibrosis.
abstract: BACKGROUND
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Dipartimento di Medicina Clinica e Sperimentale, Sezione di Malattie dell'Apparato Respiratorio, Università Federico II, Napoli, Italy. marialuisa.bocchino@unina.it
authors.forename: Marialuisa
authors.initials: M
authors.lastname: Bocchino
authors.forename: Savina
authors.initials: S
authors.lastname: Agnese
authors.forename: Evelina
authors.initials: E
authors.lastname: Fagone
authors.forename: Silvia
authors.initials: S
authors.lastname: Svegliati
authors.forename: Domenico
authors.initials: D
authors.lastname: Grieco
authors.forename: Carlo
authors.initials: C
authors.lastname: Vancheri
authors.forename: Armando
authors.initials: A
authors.lastname: Gabrielli
authors.forename: Alessandro
authors.initials: A
authors.lastname: Sanduzzi
authors.forename: Enrico V
authors.initials: EV
authors.lastname: Avvedimento
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000199:Actins / Q000378:metabolism; D015153:Blotting, Western; D002454:Cell Differentiation; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D054990:Idiopathic Pulmonary Fibrosis / Q000378:metabolism* / Q000473:pathology; D008875:Middle Aged; D009130:Muscle, Smooth / Q000737:chemistry; D016877:Oxidants / Q000494:pharmacology; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism
chemical_list: D000199:Actins; D024042:Collagen Type I; D016166:Free Radical Scavengers; D016877:Oxidants; D017382:Reactive Oxygen Species; D053773:Transforming Growth Factor beta1; D006861:Hydrogen Peroxide; D011505:Protein-Tyrosine Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D000111:Acetylcysteine