Mechanistically, inhibitor CH223191 markedly down-regulated the mRNA and protein levels of AhR and its downstream targets CYP1A1 and IL22 in colonic tissue compared with HQD treatment alone, underscoring the critical role of AhR activation in HQD-mediated alleviation of experimental colitis (Fig. 6F–J). The gene discussed is CYP1A1; the disease is colitis.