When 4-PBA was injected intraperitoneally to inhibit ER stress, the fibrosis was not further improved and the expression of GSK-3β and snail was not further inhibited in the UUO+Ad-Renalase+4-PBA group compared with the UUO+Ad-Renalase group (Figure 3A, B, C), indicating that ER stress is involved in the amelioration of renal fibrosis and regulation of GSK-3β/Snail expression by Renalase. Here, SNAI1 is linked to renal fibrosis.