SP1 and acute respiratory distress syndrome: Next, we analyzed the mRNA levels of these transcriptional factors and found that, compared with those in control group, the mRNA levels of NFKB1, NR3C1 and Egr-1 were obviously lower in ALI group, while the mRNA levels of Sp1 and PU.1 significantly increased (Fig. 5f, P < 0.05).