CD47 Deficiency Attenuates Isoproterenol-Induced Cardiac Remodeling in Mice

In this study, we investigated whether CD47 deficiency attenuates isoproterenol- (ISO-) induced cardiac remodeling in mice. Cardiac remodeling was induced by intraperitoneal (i.p.) injection of ISO (60 mg·kg^-1·d^-1 in 100 μl of sterile normal saline) daily for 14 days and was confirmed by increased levels of lactate dehydrogenase (LDH) and creatine kinase MB (CK-MB), increased heart weight to body weight (HW/BW) ratios, and visible cardiac fibrosis. Apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. Levels of malondialdehyde (MDA) and reactive oxygen species (ROS) were found to be significantly higher in the ISO group than in the control group, while superoxide dismutase (SOD) levels were suppressed in the ISO group. However, CD47 knockout significantly limited ISO-induced increases in LDH, CK-MB, and HW/BW ratios, cardiac fibrosis, oxidative stress, and apoptosis in the heart. In addition, CD47 deficiency also increased p-AMPK and LAMP2 expression and decreased HDAC3, cleaved Caspase-3, cleaved Caspase-9, LC3II, and p62 expression in cardiac tissues. In conclusion, CD47 deficiency reduced i.p. ISO-induced cardiac remodeling probably by inhibiting the HDAC3 pathway, improving AMPK signaling and autophagy flux, and rescuing autophagic clearance.