Figure 6. The BET inhibitor OTX015 blocks p300-mediated Nox4 upregulation by TGF-β1.

Lung fibroblasts IMR90 were treated either with vehicle control or OTX015 (0.5 μM) or pretreated with vehicle or OTX015 for 2 hours, before adding TGF-β1 (2 ng/mL) for 48 hours. (A) Representative Western blots showing p300, Nox4, and β-actin levels in the whole cell lysate with the above treatment. (B) Densitometric analysis of p300- or Nox4-associated signals detected (ratio to β-actin) in A. *P < 0.05, TGF-β1–treated cells without OTX015 vs. with OTX015 (mean ± SD from 3 independent experiments), by 2-tailed t test. (C) Representative images of immunofluorescence of IMR90 cells treated as in A. Cells are stained with antibodies of p300 (red) and DAPI (blue) or merged for stains of both. The images were taken with a Keyence microscope (original magnification, ×20).