Transcriptomes of B cells in the context of adenoviral TGF-ß1- or bleomycin-induced lung fibrosis in mice

Idiopathic pulmonary fibrosis (IPF) is an irreversible diffuse parenchymal lung disease of poorly defined etiology. Patients with IPF frequently demonstrate distinctive lymphoplasmacellular infiltrations within remodeled lung tissue, the relevance of which in lung fibrogenesis is still understudied. Histopathological examination of explant lung tissue of patients with IPF revealed accentuated lymphoplasmacellular accumulates in close vicinity to or even infiltrating remodeled lung tissue. Similarly, we found significant accumulations of B cells interfused with T cells within remodeled lung tissue in two murine models of adenoviral TGF-ß1 or bleomycin (BLM)-induced lung fibrosis. Such B cell accumulates coincided with significantly increased lung collagen deposition, lung histopathology and worsened lung function in WT mice. Importantly however, B cell deficient µMT KO mice responded similarly with lung tissue remodeling and worsened lung function upon either AdTGF-ß1 or BLM treatment as did WT mice. Comparative transcriptomic profiling of sorted B cells collected from lungs of AdTGF-ß1 and BLM exposed WT mice identified a large set of commonly regulated genes, however with significant enrichment observed for gene ontology terms (GO terms) apparently not related to lung fibrogenesis. Collectively, although we observed B cell accumulates in lungs of IPF patients as well as two experimental models of lung fibrosis, comparative profiling of characteristic features of lung fibrosis between WT and B cell-deficient mice did not support a major involvement of B cells in lung fibrogenesis in mice. Overall design: RNA samples of mice exposed to AdTGF-ß1/AdCL or Bleomycin/saline for 14 or 21 days.