Fig. 5

Activation of KYN pathway in human lung ECs upon IFNγ stimulation. A Fold changes of IDO1 mRNA expression levels upon vehicle (10% FBS-PBS) or IFNγ (10 ng/mL) treatment were examined using HULEC-5a cells. B Western blotting analysis of IDO1 expression in HULEC-5a cells upon treatment with vehicle or IFNγ (10 ng/mL) for 48 h. GAPDH expression was analyzed as a loading control. Uncropped images are shown in Additional file 5. C Relative levels of TRP, KYN, and QUNA in supernatant of HULEC-5a cells treated with vehicle or IFNγ (10 ng/mL) for 48 h are shown. D Relative mRNA expression levels of major metabolic enzymes of KYN pathway (KMO, KYNU, and 3-HAO) in differentiated macrophage-like cell lines (dTHP1 and dU937) and HULEC-5a cells. Each bar represents the mean ± standard deviation of three independent experiments. Statistical significance of mean values was tested using Student’s t-test (ns, not significant; **p-value < 0.01; ***p-value < 0.001). Bonferroni correction was conducted for multiple comparisons