FIGURE 4.

Reducing β-actin availability prevents hyperoxia-induced increases in eNOS-β-actin association, eNOS activity, and formation of NO and peroxynitrite. PAEC were transfected with a scramble siRNA or a siRNA against β-actin. After 48 h, the cells were exposed to normoxia or hyperoxia (95% oxygen) for 24 h. Then, the protein contents of eNOS and β-actin (A) and eNOS-β-actin association (B and C), eNOS activity (D), NO (E), and peroxynitrite (F) were determined as described under “Experimental Procedures.” A and B are representative immunoblots from three experiments. C is a bar graph showing the changes in the ratio of eNOS to β-actin in the immunoprecipitates. Results are expressed as mean ± S.D.; n = three experiments. *, p < 0.05 versus normoxia in scramble siRNA group. **, p < 0.05 versus normoxia group; #, p < 0.05 versus control (without uric acid).