ENPP2 and rheumatoid arthritis: For example, ATX is induced in mouse lung bronchial epithelial cells and alveolar macrophages during the bleomycin-induced pulmonary inflammation and fibrosis [17, 18], and upregulation of ATX expression is observed in synovial fibroblasts from rheumatoid arthritis (RA) patient as well as in the mouse model of arthritis [19, 20].