title: Pirfenidone inhibits p38-mediated generation of procoagulant microparticles by human alveolar epithelial cells.
abstract: Pirfenidone is a drug recently approved for idiopathic pulmonary fibrosis but its mechanisms of action are partially unknown. We have previously demonstrated that the airways of patients with idiopathic pulmonary fibrosis contain procoagulant microparticles that activate coagulation factor X to its active form, Xa, a proteinase that signals fibroblast growth and differentiation, thus potentially contributing to the pathogenesis of the disease. We also reported that in vitro exposure of human alveolar cells to H2O2 causes microparticle generation. Since p38 activation is involved in microparticle generation in some cell models and p38 inhibition is one of the mechanisms of action of pirfenidone, we investigated the hypothesis that H2O2-induced generation of microparticles by alveolar cells is dependent on p38 phosphorylation and is inhibited by pirfenidone. H2O2 stimulation of alveolar cells caused p38 phosphorylation that was inhibited by pirfenidone. The drug also inhibited H2O2 induced microparticle generation as assessed by two independent methods (solid phase thrombin generation and flow cytometry). The shedding of microparticle-bound tissue factor activity was also inhibited by pirfenidone. Inhibition of p38-mediated generation of procoagulant microparticle is a previously unrecognized mechanism of action of the antifibrotic drug, pirfenidone.
authors.affiliation: Laboratorio di Biologia Cellulare Respiratoria, Dipartimento di Patologia Chirurgica, Medica, Molecolare e di Area Critica, Università di Pisa, Pisa, Italy.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Neri
authors.affiliation: SSD Analisi ChimicoCliniche ed ImmunoAllergologia, USL1, Massa e Carrara, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Lombardi
authors.affiliation: Laboratorio di Biologia Cellulare Respiratoria, Dipartimento di Patologia Chirurgica, Medica, Molecolare e di Area Critica, Università di Pisa, Pisa, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Faìta
authors.affiliation: Laboratorio di Biologia Cellulare Respiratoria, Dipartimento di Patologia Chirurgica, Medica, Molecolare e di Area Critica, Università di Pisa, Pisa, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Petrini
authors.affiliation: Laboratorio di Biologia Cellulare Respiratoria, Dipartimento di Patologia Chirurgica, Medica, Molecolare e di Area Critica, Università di Pisa, Pisa, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Balìa
authors.affiliation: Laboratorio di Biologia Cellulare Respiratoria, Dipartimento di Patologia Chirurgica, Medica, Molecolare e di Area Critica, Università di Pisa, Pisa, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Scalise
authors.affiliation: Laboratorio di Biologia Cellulare Respiratoria, Dipartimento di Patologia Chirurgica, Medica, Molecolare e di Area Critica, Università di Pisa, Pisa, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Pedrinelli
authors.affiliation: Laboratorio di Biologia Cellulare Respiratoria, Dipartimento di Patologia Chirurgica, Medica, Molecolare e di Area Critica, Università di Pisa, Pisa, Italy.
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Paggiaro
authors.affiliation: Laboratorio di Biologia Cellulare Respiratoria, Dipartimento di Patologia Chirurgica, Medica, Molecolare e di Area Critica, Università di Pisa, Pisa, Italy. Electronic address: alessandro.celi@med.unipi.it.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Celi
mesh_terms: D000072283:A549 Cells; D056809:Alveolar Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D055252:Cell-Derived Microparticles; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D054990:Idiopathic Pulmonary Fibrosis / Q000188:drug therapy / Q000503:physiopathology; D018384:Oxidative Stress / Q000187:drug effects*; D010766:Phosphorylation / Q000187:drug effects; D011728:Pyridones / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D011728:Pyridones; D006861:Hydrogen Peroxide; C093844:pirfenidone; D048051:p38 Mitogen-Activated Protein Kinases
keywords: Human alveolar epithelial cells; Idiopathic pulmonary fibrosis; Microparticles; Pirfenidone; Tissue factor; p38