Correction: Uridine alleviates the aging of alveolar epithelial cells in idiopathic pulmonary fibrosis through the Keap1-Nrf2 signaling pathway

The original version of this Article contained errors in Figure 2 where there is an overlap between the images representing the PBS group and the Uridine (20 mg/kg) group in panel (i), and in Figure 4 where the originally published image of the 100 μM Uridine group belonged to a different experimental group in panel (a). The original Figures 2 and 4 and accompanying legend appear below. Fig. 2 Uridine Improves BLM-Induced Pulmonary Fibrosis in Mice. ( a ) Macroscopic view of lung tissues from mice treated with uridine and nintedanib following intratracheal instillation of 2 mg/kg BLM for 10 days, followed by 10 days of oral gavage treatment with uridine (20, 40 mg/kg) and nintedanib (100 mg/kg). ( b ) Lung weight/body weight ratio in mice treated with uridine and nintedanib. ( c ) Representative images of lung tissues stained with H&E from mice treated with uridine and nintedanib. ( d ) Ashcroft score of lung fibrosis in histopathological sections from mice. ( e ) Representative images of lung tissues stained with Masson’s trichrome and Sirius Red from mice treated with uridine and nintedanib. ( f ) Hydroxyproline levels in lung tissues from mice treated with uridine and nintedanib. ( g ) Representative images of immunofluorescence staining for epithelial markers Ki67 and E-cadherin in lung tissues from mice treated with uridine and nintedanib. ( h ) Western blot analysis of epithelial markers Ki67 and E-cadherin expression levels in lung tissues from mice treated with uridine and nintedanib. ( i ) Representative images of immunofluorescence staining for fibrotic markers α-SMA and Collagen1a1 in lung tissues from mice treated with uridine and nintedanib. ( j ) Western blot analysis of fibrotic markers α-SMA and Collagen1a1 expression levels in lung tissues from mice treated with uridine and nintedanib. Bars in ( c , e , g , i ) represent 100 μm. Data in ( b , d , 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). Full size image 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). Full size image