beta-arrestin-mediated signal transduction participates in laminar shear stress-induced production of nitric oxide in endothelial cells

Abstract

Endothelial cells are capable of converting mechanical stimuli into intracellular signals generating vasoactive factors such as nitric oxide (NO). A great body of evidence suggests that β-arrestins play a role not only on GPCR desensibilization but also in mechanotransduction. The aim of this study was to test the hypothesis that laminar shear stress (SS)-induced NO production by endothelial cells requires the activation of the β-arrestin signaling pathway. Towards this end, human saphenous vein endothelial cells (SVEC) were transfected with siRNA against the isoforms 1 and 2 of β-arrestins and subsequently subjected to SS (15 dynes/cm2) for 10 minutes. We found that the SS-induced production of nitrite in the cell culture medium was significantly decreased in SVEC silenced for β-arrestin 1 and 2 compared to control cells (326±44 vs. 166±17%; P < 0.001, n=5). Furthermore, silencing of β-arrestin 1 and 2 significantly attenuated the phosphorylation levels of AKT at the serine residue 473 (99±22 vs. 293±42% in control; P <0.001, n=5) and led to a non-significant trend towards an increase of ERK phosphorylation (157±71 vs.107±5% in control; P= 0.3670, n=5). Altogether, we provide evidence that β-arrestins play a role on laminar SS-induced generation of NO associated with AKT activation in endothelial cells.