In vitro polarization of macrophages reveals high expression of OPN in M2c macrophages. The J774A macrophage cell line was induced to different macrophage subtypes by exposure to polarizing cytokines in vitro to model macrophage polarization. Exposure to IFNγ polarizes to M1, exposure to IL4 polarizes to M2a, and exposure to IL10 polarizes to M2c. NT, not treated. Polarizing treatments are indicated under each bar of the graph. (A) Expression of iNOS (M1), Arg-1 (M2a), and IL-10 (M2c) was assessed by quantitative RT-PCR to confirm macrophage phenotype (top). (B) Quantitative RT-PCR assessment of OPN mRNA expression in polarized macrophages. Each bar in the plots from A and B represents the mean value calculated from six samples collected in three different experiments. (C) Western blot of polarized macrophage extracts reveals high OPN in M2c macrophages. Polarizing cytokines are indicated above the lanes. Vertical bars represent standard error. P-values relative to nontreated cells are indicated based on Student’s t test.