E2F4 and acute respiratory distress syndrome: A significant increase was also observed in the LPS+mBM-MSC-p130 and LPS+mBM-MSC-E2F4 groups compared to the ARDS group (p < 0.05), and the increase was much greater than that in the LPS+mBM-MSC-NC group (p < 0.05) (Fig. 5d, relative intensity of each band on the representative image was shown in Additional file 1).