Moreover, glycoprotein nonmetastatic melanoma protein B (GPNMB) was identified as one of the most highly upregulated proteins (Supplementary Table 1) that might be related to the pulmonary fibrosis process in silica-treated mice according to protein interaction network analysis (Fig. 2c, Supplementary Fig. 3h, i). Here, GPNMB is linked to pulmonary fibrosis.