Figure 2.

Histone deacetylase (HDAC) 4 protein levels are decreased in IPF fibroblasts. (A) IPF and control lung fibroblasts were seeded on polymerized type I collagen matrices as a function of time. Top panel: Phosphorylated HDAC4 (pHDAC4) and HDAC4 expression were examined by Western blot analysis. GAPDH is shown as a loading control. Bottom panel: pHDAC4 and HDAC4 levels were quantified by densitometry. (B) IPF fibroblasts were pretreated with the proteasome inhibitor MG132 (20 nM; 60 min) or vehicle control (ethanol [ETOH]) and seeded on polymerized collagen for 0, 2, 4, or 8 hours. HDAC4 protein levels were quantified by Western blot analysis. GAPDH is shown as a loading control. All experiments were repeated with three independent cell lines to confirm the findings.