Figure 4. Effect of PI3K-Akt pathway activation and PTEN expression on lung fibroblast proliferation.

Activation of PI3K-Akt pathway (A, Western blot) in lung fibroblasts at 72 hours after 1 µg/mL LPS challenge, as detected by expression of Ser473 phospho-Akt. siRNA-mediated TLR4 knockdown (1×10⁸ TU/mL for 48 hours) was used to assess the effect of TLR4 on PI3K-Akt pathway activation. PI3K inhibitor Ly294002 (50 µmol/L for one hour) was used to assess the effect of PI3K-Akt pathway on lung fibroblast proliferation. * p<0.05 vs. negative control group (Column 2); ^† p<0.05 vs. positive control group (Column 3). Activation of PI3K-Akt pathway in lung fibroblasts (B, Western blot), as detected by expression of Ser473 phospho-Akt after treatment with different concentrations of PTEN inhibitor bpV(phen) for 0.5 hour. * p<0.05 vs. negative control group (Column 1). DNA synthesis (C, BrdU assay) in LPS-challenged lung fibroblasts after bpV(phen) (1 µM for 0.5 hour) and/or Ly294002 (50 µmol/L for one hour) treatment. * p<0.05 vs. negative control group (Column 1); ^† p<0.05 vs. positive control group (Column 2). Columns represent mean values and error bars represent SD. Blots are representative of three independent experiments.