Effect of adiponectin on cardiac β-catenin signaling pathway under angiotensin II infusion

Obesity is associated with heart failure and cardiac hypertrophy. Adiponectin has been shown to play a protective role for cardiovascular diseases. The β-catenin signaling pathway is deeply involved in cardiac hypertrophy. However, the effect of adiponectin on β-catenin signaling has not been investigated in cardiac hypertrophy. Present study aimed to clarify the involvement of adiponectin and β-catenin signaling pathway in the mouse model of angiotensin II (AngII)-induced cardiac hypertrophy. In hearts of Wild type (WT) mice, AngII dose-dependently augmented cytosolic β-catenin protein level. WT and adiponectin knockout (Adipo-KO) mice were administered with AngII at 2.4 mg/kg/day for 14 days and were also injected with adenovirus expressing the adiponectin (Ad-Adipo) or the β-galactosidase (Ad-βgal). Cardiac mRNA levels relating to hypertrophy and β-catenin signaling were increased in Adipo-KO mice and these changes were reversed by Ad-Adipo. Phosphorylation of Akt was increased in Adipo-KO mice and such increases were reversed by Ad-Adipo. Furthermore, the phosphorylation of glycogen synthase kinase 3β (GSK3β) at Ser(9) and cytosolic β-catenin level were increased in Adipo-KO mice and they were significantly reduced by Ad-Adipo treatment. Phosphorylation of mammalian target of rapamycin (mTOR) was reduced by Ad-Adipo-mediated adiponectin supplementation in WT and Adipo-KO mice. The current study suggests that adiponectin attenuates AngII-induced cardiac hypertrophic signals partly through Akt/GSK3β/β-catenin and Akt/mTOR pathways.