Regulation of the endothelin system by shear stress in human endothelial cells

Abstract

In this study, the effect of shear stress on the expression of genes of the human endothelin‐1 system was examined. Primary cultures of human umbilical vein endothelial cells (HUVEC) were exposed to laminar shear stress of 1, 15 or 30 dyn cm−2 (i.e. 0.1, 1.5 or 3 N m−2) (venous and two different arterial levels of shear stress) in a cone‐and‐plate viscometer. Laminar shear stress transiently upregulates preproendothelin‐1 (ppET‐1) mRNA, reaching its maximum after 30 min (approx 1.7‐fold increase). In contrast, long‐term application of shear stress (24 h) causes downregulation of ppET‐1 mRNA in a dose‐dependent manner. Arterial levels of shear stress result in downregulation of endothelin‐converting enzyme‐1 isoform ECE‐1a (predominating in HUVEC) to 36.2 ± 8.5%, and isoform ECE‐1b mRNA to 72.3 ± 1.9% of static control level. The endothelin‐1 (ET‐1) release is downregulated by laminar shear stress in a dose‐dependent manner. This downregulation of ppET‐1 mRNA and ET‐1 release is not affected by inhibition of protein kinase C (PKC), or tyrosine kinase. Inhibition of endothelial NO synthase (L‐NAME, 500 μm) prevents downregulation of ppET‐1 mRNA by shear stress. In contrast, increasing degrees of long‐term shear stress upregulate endothelin receptor type B (ETB) mRNA by a NO‐ and PKC‐, but not tyrosine kinase‐dependent mechanism. In conclusion, our data suggest the downregulation of human endothelin synthesis, and an upregulation of the ETB receptor by long‐term arterial laminar shear stress. These effects might contribute to the vasoprotective and anti‐arteriosclerotic potential of arterial laminar shear stress.

Emergence of Smooth Muscle Cell Endothelin B–Mediated Vasoconstriction in Lambs With Experimental Congenital Heart Disease and Increased Pulmonary Blood Flow

“…Although increasing in vitro data suggest that changes in mechanical forces alter ET-1 signaling, few data are available on the regulation of ET receptor signaling. 23,24 Therefore, the potential mechanisms for the current receptor changes are unknown and warrant further investigation.…”

Sequential Activation of Protein Kinase C (PKC)-α and PKC-ε Contributes to Sustained Raf/ERK1/2 Activation in Endothelial Cells under Mechanical Strain

“…PKC-␣ belongs to a Ca 2ϩ -dependent group, and the isoforms PKC-⑀ and PKC-belong to a Ca 2ϩ -independent group. Studies have indicated that PKC is involved in shear stress-and cyclic strain-induced gene expression of platelet-derived growth factor and Et-1 in ECs (19,20). Indeed, PKC-⑀ is required for fluid shear stress-mediated activation of ERK1/2 in ECs (21).…”

“…It is well recognized that when ECs are subjected to hemodynamic forces, Ca 2ϩ mobilization plays an essential role in endothelial responses (20,35). When ECs are under hemodynamic treatment, a rapid increase of [Ca 2ϩ ] i (35,36), inositol triphosphate and DAG (17) occurs.…”

The Neurogenic Vasodilator Response to Endothelin‐1: A Study in Human Skin In Vivo

“…The source of the dialysed NO within the flare is unclear, as a number of cell types within the skin, including fibroblasts, keratinocytes and mast cells, constitutively express NOS (Weller, 1997). The finding that ET-receptor antagonism also reduces NO suggests a role for flow-mediated endothelial NO release via ETB receptors (Morawietz et al 2000) in addition to NO derived from tissue cells and nerves where similar receptor subtypes have been localised (Dashwood & Thomas, 1997). The relatively small amount of histamine released at the focus of the intradermal injection of ET_1 strongly suggests that histamine does not play a major role in modulating the neurogenic response to ET_1.…”