S100a4 Is Secreted by Alternatively Activated Alveolar Macrophages and Promotes Activation of Lung Fibroblasts in Pulmonary Fibrosis
Idiopathic pulmonary fibrosis (IPF) is a devastating interstitial lung disease, characterized by damage of lung epithelial cells, excessive deposition of extracellular matrix in the lung interstitium, and enhanced activation and proliferation of fibroblasts. S100a4, also termed FSP-1 (fibroblast-specific protein-1), was previously considered as a marker of fibroblasts but recent findings in renal