FIG. 7.
Mito-catalase, but not MnSOD, blocks hyperoxia-induced PDE5 activity and restores cGMP responsiveness to exogenous NO. FPASMC were exposed to 21% O2/5% CO2 or 95% O2/5% CO2 for 30 min±MnSOD, mito-catalase, or empty adenoviral vector, followed by recovery for 30 min in 21% O2/5% CO2. (A) PDE5-specific cGMP hydrolytic activity in the absence or presence of MnSOD overexpression is measured using a commercially available colorimetric assay (n=6, read in duplicate). (B) FPASMC±MnSOD overexpression±DETANONOate (100 μM, NO) were assayed for cGMP by EIA, and cGMP was normalized to total protein (n=13, read in duplicate). (C) PDE5-specific cGMP hydrolytic activity in the absence or presence of mito-catalase overexpression is measured as in A (n=9, read in duplicate). (D) FPASMC±mito-catalase overexpression±DETANONOate were assayed for cGMP and normalized to total protein as in B (n=18, read in duplicate). Data are shown as mean±SEM. *p<0.05 vs. untreated FPASMC in 21% O2/5% CO2; #p<0.05 vs. untreated FPASMC in 95% O2/5% CO2; +p<0.05 vs. NO-treated PASMC in 21% O2/5% CO2, &p<0.05 vs. NO-treated PASMC in 95% O2/5% CO2.