Multiple stromal populations contribute to pulmonary fibrosis without evidence for epithelial to mesenchymal transition

摘要

Idiopathic pulmonary fibrosis (IPF) is a debilitating disease in which the delicate gas exchange region of the lung is gradually replaced by accumulations of ECM and myofibroblasts. These cells are commonly thought to produce components of the ECM, including collagen. Conflicting ideas about the cellular origin of the fibrotic lesions may slow progress to the development of effective therapies for IPF. To address this problem, we combined the power of cell lineage tracing in mice with a model of pulmonary fibrosis induced by bleomycin, an anticancer agent that often results in pulmonary fibrosis as a side effect. We provide evidence that the behaviors of pericytes, a cell type associated with blood vessels, and epithelial cells are modulated in response to bleomycin-induced lung injury. However, neither cell type Ⅰs a major source of myofibroblasts. These findings should help to focus future efforts at developing therapies for the treatment of IPF.