Surendran et al. (Surendran et al., 2002) detected an increased number of MCs and enhanced WNT4 protein levels in a rat model of unilateral ureteral obstruction; these increases in expression were proportional to the high content of collagen I and a-smooth muscle actin, thus indicating that WNT4 can induce the formation of fibroblasts in vitro (Liu et al., 2020a). Here, WNT4 is linked to Ureteral obstruction.