Pravastatin™ suppresses venous shear stress dependent induction of Aquaporin 1 protein expression in human umbilical vein endothelial cells in vitro

Abstract

Aquaporins (AQPs) are transmembrane water channels that facilitate osmotically-driven water flux. AQP1, expressed in vascular endothelium, functions in cell migration, wound healing, and cell volume regulation in response to mechanical stimuli. AQP1 protein abundance is enhanced in cultured human umbilical vein endothelial cells (HUVECs) in response to fluid shear stress. Statin drugs suppress the development of vein intimal hyperplasia by affecting endothelial response to shear stress. Statins may also regulate the expression of specific AQPs. Therefore, it is hypothesized that AQP1 may function within the mechanosensory complex in endothelial cells and is subject to shear stress-induced modulation of expression by statins. HUVECs were cultured in microfluidic chambers under static (0 dynes/cm2) and venous fluid shear stress (6 dynes/cm2) in the presence or absence of 5 µM Pravastatin™. Fluorescent immunocytochemistry was used to detect AQP1 protein expression. AQP1 expression increased 1.4-fold (p < 0.05) after 24 hours, and 1.5-fold (p < 0.05) after 48 hours, under venous fluid shear stress as compared to the control. This shear stress-induced expression was blocked by incubation with Pravastatin and reduced by 27% (p < 0.05; control vs. venous shear stress with Pravastatin). Pravastatin had no effect on AQP1 expression in static cultures (p > 0.05 vs. control). Shear stress-dependent induction of AQP1 protein expression is suppressed by Pravastatin. Statin drugs might have a potential function in regulating the expression of AQPs that is independent of their cholesterol-lowering function and related to the regulation of AQP1 in vascular endothelial cells.