Local apoptosis promotes collagen production by monocyte-derived cells in transforming growth factor β1-induced lung fibrosis

摘要

BackgroundCollagen-containing leukocytes (CD45⁺Col-I⁺) accumulate in diseased and fibrotic tissues. However, the precise identity of these cells and whether injury is required for their recruitment remain unknown. Using a murine model of pulmonary fibrosis in which an inducible, bioactive form of the human transforming growth factor (TGF)-β1 gene is targeted to the lung, we characterized the cell surface phenotype of collagen-containing CD45⁺ cells in the lung and tested the hypothesis that apoptotic cell death responses are essential to the accumulation of CD45⁺Col-I⁺ cells.