Induction of NEDD4 under simulated microgravity

Abstract

Vascular endothelial cells are exposed to mechanical forces e.g. wall shear stress, wall tension, and pulsatile stretch, which are modulated by the gravitational field. The effects of microgravity may influence endothelial cell function including protein synthesis and degradation.Therefore, this study was designed to investigate microgravity dependent effects on the ubiquitin‐ligase NEDD4 in endothelial cells. In order to produce microgravity endothelial cells (EA hy926, HUVEC) were seeded on microcarriers and cultured in the Rotating Wall Vessel for 24 h and 48 h. Controls were kept under normal gravity or exposed to shear stress using a cone and plate apparatus (6 dyn\cm2, 24 h). Gene expression and protein concentration were analysed by real‐time RT‐PCR and Western blotting, respectively. Our results indicate that NEDD4 is upregulated to 200% under microgravity and downregulated to 70% by shear stress relative to controls (1G, no shear). The present data suggest that NEDD4 is sensitive to mechanical forces; the induction under microgravity may be a mechanism to enhance protein degradation in endothelial cells.