In line with our hypothesis, Gpr4−/− mice tolerated AOM/DSS treatment significantly better than WT mice, indicated by significantly increased weight gain, a decreased clinical disease activity score, significantly decreased spleen weight, significantly increased colon length, and a significantly ameliorated histologic score in both colon and small bowel, reflecting protection from inflammatory processes (Fig. S2A–F). Here, GPR4 is linked to infectious otitis media.