Fig. 4

Uridine Activates the Nrf2 Signaling Pathway. (a) Representative images of ROS fluorescence in A549 cells induced by BLM with uridine treatment. (b) Representative immunofluorescence images of Nrf2 in uridine-treated A549 cells. (c) qRT-PCR analysis of Nrf2 gene expression levels in uridine-treated A549 cells. (d) Western blot analysis of Nrf2 protein expression levels in uridine-treated A549 cells. (e) Western blot analysis of downstream genes of Nrf2 (NQO1, HO-1, GCLM, GCLC) expression levels in uridine-treated A549 cells. (f) qRT-PCR analysis of downstream gene expression levels of Nrf2 in uridine-treated A549 cells. (g) Treatment of A549 cells with CHX (300 µM) followed by Western blot analysis of Nrf2 protein levels at 0, 8, 16, and 24 h. (h) Treatment of A549 cells with CHX (300 µM) and MG132 (10 µM) followed by Western blot analysis of Nrf2 protein levels at 0, 8, 16, and 24 h. (i) Treatment of A549 cells with CHX (300 µM) and uridine (300 µM) followed by Western blot analysis of Nrf2 protein levels at 0, 8, 16, and 24 h. Bars in (a) represent 200 μm, and in (b) represent 50 μm. Data in (c) and (f) are presented as mean ± SD (n = 3, *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001; ns indicates no significance; student’s t-test).