Fig. 4.

Overexpression of type I cAMP-dependent protein kinase (PKA) regulatory α-subunit (RIα) in adult mouse ventricular myocytes (AMVMs) increases apoptosis upon oxidative stress. COXIV, cytochrome-c oxidase. A: immunoblot analysis of AMVM cell cultures first infected with adenovirus to overexpress regulatory α-subunit (RΙα) or green fluorescent protein (GFP) controls (Ad-RΙα and Ad-GFP, respectively) and then exposed to oxidant stress (10 µM H₂O₂) for 30 min. B: quantification of RIα expression from data in A (n = 4 biological replicates). Data are presented as means ± SD. *P < 0.05 compared with “Ad-GFP control (Ctrl)” condition. C: quantification of cleaved poly-ADP ribose polymerase (Cl PARP) expression from data in A (n = 4 biological replicates). Data are presented as means ± SD. *P < 0.05 compared with “Ad-GFP Ctrl” condition. D: immunoblot analysis of cardiac troponin I phosphorylation (p-TnI) from AMVM cells treated similarly as in A. E: quantification of p-cTnI data from D (n = 3 biological replicates). Data are presented as means ± SD. *P < 0.05; **P < 0.01.