Fig. 5: AHR functional studies in HepaRG and U-87 MG cells

A mRNA expression determined by qRT-PCR after AHR KD in HepaRG cells. TDO2, KMO, and KYNU expression was significantly increased and AHRR and CYP1A1 expression was significantly decreased following AHR KD. B Protein expression analysis for AHR, TDO2, KMO, and KYNU by Western blot analysis after AHR KD in HepaRG cells. C mRNA expression in HepaRG cells determined by qRT-PCR after 24-h treatment with 1 µM 3-MC, an AHR agonist. TDO2, KMO, and KYNU expression was significantly decreased. AHRR, CYP1A1 (in HepaRG), was  induced by 3-MC, indicating that AHR was activated by the treatment. D KYN concentrations in HepaRG cell culture media after AHR and AHR plus KMO or KYNU KD. E TDO2, KMO, and KYNU expression was significantly increased while AHRR and CYP1B1 expression was significantly decreased following AHR KD. F AHR, TDO2, KMO, and KYNU protein concentrations were significantly altered in U-87 MG cells after AHR KD. G mRNA expression in U-87 MG cells after 1 µM 3-MC treatment showed significant decreases in TDO2, KMO, and KYNU expression and significant increases in AHRR and CYP1B1 expression. H KYN concentrations in U-87 MG cell culture media were significantly decreased after AHR KD but were less decreased after AHR KD together with KMO or KYNU KD. N ≥ 3 for all experiments. Data = mean ± SEM, with statistical significance determined by two-tailed t-test denoted as *P < 0.05, **P < 0.01 and ***P < 0.001 when compared with control. ns = not significant