OBG-like ATPase 1 inhibition attenuates angiotensin II-induced hypertrophic response in human ventricular myocytes via GSK-3beta/beta-catenin signaling.

Obg-like ATPase 1 (OLA1) that possesses both GTP and ATP hydrolyzing activities has been shown to be involved in translational regulation of cancer cell growth and survival. Also, GSK3 beta signalling has been implicated in cardiac development and disease. However, the role of OLA1 in pathological cardiac hypertrophy is unknown. We sought to understand the mechanism by which OLA1 regulates GSK3 beta-beta-Catenin signalling and its functional significance in angiotensin-II (ANG II)-induced cardiac hypertrophic response. OLA1 function and its endogenous interaction with GSK3 beta/beta-catenin signalling in cultured human ventricular cardiomyocytes (AC16 cells) and mouse hearts (in vivo) was evaluated with/without ANG II-stimulated hypertrophic response. ANG II administration in mice increases myocardial OLA1 protein expression with a corresponding increase in GSK3 beta phosphorylation and decrease in beta-Catenin phosphorylation. Cultured cardiomyocytes treated with ANG II show endogenous interaction between OLA1 and GSK3 beta, nuclear accumulation of beta-Catenin and significant increase in cell size and expression of hypertrophic marker genes such as atrial natriuretic factor (ANF; NPPA) and beta-myosin heavy chain (MYH7). Intriguingly, OLA1 inhibition attenuates the above hypertrophic response in cardiomyocytes. Taken together, our data suggest that OLA1 plays a detrimental role in hypertrophic response via GSK3 beta/beta-catenin signalling. Translation strategies to target OLA1 might potentially limit the underlying molecular derangements leading to left ventricular dysfunction in patients with maladaptive cardiac hypertrophy.