PTGER4 and renal fibrosis: In a murine model of ureteral obstruction, the development of renal fibrosis, the accumulation of macrophages, and the formation of proinflammatory and profibrotic cytokines were significantly augmented in the kidneys of EP4 knock-out mice and suppressed by an EP4 agonist, ONO-4819 (Nakagawa et al., 2012).