| First Author | Gao MH | Year | 2017 |
| Journal | PLoS One | Volume | 12 |
| Issue | 8 | Pages | e0181282 |
| PubMed ID | 28767701 | Mgi Jnum | J:248053 |
| Mgi Id | MGI:5917430 | Doi | 10.1371/journal.pone.0181282 |
| Citation | Gao MH, et al. (2017) Cardiac-directed expression of a catalytically inactive adenylyl cyclase 6 protects the heart from sustained beta-adrenergic stimulation. PLoS One 12(8):e0181282 |
| abstractText | OBJECTIVES: Increased expression of adenylyl cyclase type 6 (AC6) has beneficial effects on the heart through cyclic adenosine monophosphate (cAMP)-dependent and cAMP-independent pathways. We previously generated a catalytically inactive mutant of AC6 (AC6mut) that has an attenuated response to beta-adrenergic receptor stimulation, and, consequently, exhibits reduced myocardial cAMP generation. In the current study we test the hypothesis that cardiac-directed expression of AC6mut would protect the heart from sustained beta-adrenergic receptor stimulation, a condition frequently encountered in patients with heart failure. METHODS AND RESULTS: AC6mut mice and transgene negative siblings received osmotic mini-pumps to provide continuous isoproterenol infusion for seven days. Isoproterenol infusion caused deleterious effects that were attenuated by cardiac-directed AC6mut expression. Both groups showed reduced left ventricular (LV) ejection fraction, but the reduction was less in AC6mut mice (p = 0.047). In addition, AC6mut mice showed superior left ventricular function, manifested by higher values for LV peak +dP/dt (p = 0.03), LV peak -dP/dt (p = 0.008), end-systolic pressure-volume relationship (p = 0.003) and cardiac output (p<0.03). LV samples of AC6mut mice had more sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2a) protein (p<0.01), which likely contributed to better LV function. AC6mut mice had lower rates of cardiac myocyte apoptosis (p = 0.016), reduced caspase 3/7 activity (p = 0.012) and increased B-cell lymphoma 2 (Bcl2) expression (p = 0.0001). CONCLUSION: Mice with cardiac-directed AC6mut expression weathered the deleterious effects of continuous isoproterenol infusion better than control mice, indicating cardiac protection. |
