In a chimeric study with Smad3−/− and Smad3+/+ GFP+ bone marrow transplanted into irradiated mice with unilateral ureteral obstruction (UUO), Smad3-deleted macrophage (Smad3−/− GFP+ F4/80+) failed to undergo MMT to generate myofibroblasts (GFP+ α-SMA+) for collagen-I deposition in the fibrotic kidney, which is in contrast to the profound MMT activity of Smad3 wildtype macrophage (Smad3+/+ GFP+ F4/80+) [48]. Here, SMAD3 is linked to Ureteral obstruction.