B-cell activating factor regulates IL-1?- and IL-17A-mediated pulmonary fibrosis in mice - 04/04/15
Résumé |
Introduction |
Idiopathic pulmonary fibrosis (IPF) is a progressive devastating, yet untreatable fibrotic disease of unknown origin. We investigated the contribution of the B-cell activating factor (BAFF), a TNF family member recently implicated in the regulation of pathogenic IL-17-producing cells in autoimmune diseases.
Methods |
The contribution of BAFF was assessed in a murine model of lung fibrosis induced by airway administered bleomycin, an intercalating agent which causes DNA strand breaks. Lung fibrosis was evaluated in Baff deficient mice and in wild-type mice after neutralization of BAFF with BAFF-R-Ig. Lung cells from bleomycin-treated mice were collected at day 7, labeled with anti-CD115, anti-CD3, anti-CD19 and anti-Gr1 antibodies and sorted by FACS for evaluation of BAFF mRNA expression by qPCR. BAFF was quantified in bronchoalveolar lavage fluid (BALF) of controls and patients with IPF.
Results |
We show that murine BAFF levels were strongly increased in the bronchoalveolar space and lungs after bleomycin exposure. We identified Gr1+ neutrophils as an important source of BAFF upon BLM induced lung inflammation and fibrosis. Genetic ablation of BAFF or BAFF neutralization by a soluble receptor significantly attenuated pulmonary fibrosis and IL-1β levels. We further demonstrate that bleomycin-induced BAFF expression and lung fibrosis were IL-1β- and IL-17A-dependent. BAFF was required for rIL-17A-induced lung fibrosis and augmented IL-17A production by CD3+ T cells from murine fibrotic lungs ex vivo. Finally, we report elevated levels of BAFF in bronchoalveolar lavages from IPF patients.
Conclusion |
The present data, demonstrating a critical role of BAFF by amplifying the IL-17A effect in experimental lung fibrosis, together with increased BAFF levels in the airways of patients with IPF, suggest that BAFF might be a therapeutic target of IPF.
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