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Comparison of the effect of pulsatile and nonpulsatile shear stress on adherens junctions in human endothelial cells
Author(s) -
Plant S.,
Leach L.
Publication year - 2002
Publication title -
journal of anatomy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 118
eISSN - 1469-7580
pISSN - 0021-8782
DOI - 10.1046/j.1469-7580.2002.00047_26.x
Subject(s) - adherens junction , pulsatile flow , umbilical vein , shear stress , actin , microbiology and biotechnology , actin cytoskeleton , cytoskeleton , biology , cadherin , biophysics , anatomy , chemistry , cell , materials science , in vitro , endocrinology , biochemistry , composite material
In vivo , endothelial cells experience shear stress resulting from pulsatile flow. Many publications have shown that the pulsatile nature of this flow influences endothelial function and structure including intracellular calcium concentrations, cell shape and actin stress fibre formation. A recent in vitro study using bovine aortic cells showed exposure to nonpulsatile flow caused transient disruption of adherens junctions through perturbation of VE‐cadherin and the disassembly of the actin cytoskeleton. The aim of this study was to observe the responses of the adherens junctional molecule VE‐cadherin, and F‐actin, to pulsatile and nonpulsatile flow in human endothelial cells over a 48‐h period. Human umbilical vein endothelial cells (HUVEC) were isolated from fresh umbilical cords taken from elective caesarean sections ( n = 6). At passages 2–4 the cells were seeded onto glass coverslips pretreated with 3‐aminoproryaltriethoxysilane (APES). 48 h after reaching confluence the cells were transferred to a parallel plate flow chamber and exposed to slowly increased pulsatile or nonpulsatile laminar flow, producing a final shear stress of 1.5 dynes/cm 2 . Cells were left under flow for up to 48 h. At t = 0, 8 and 48 h immunocytochemistry was used to visualise VE‐cadherin and phalloidin‐TRITC to visualise F‐actin. At t = 0, VE‐cadherin was localised at cell‐cell contacts and the cells contained randomly oriented stress fibres and cortically located perijunctional actin. Following 8 h exposure to both types of flow no VE‐cadherin or actin could be detected. After 48 h exposure VE‐cadherin and F‐actin had returned to the junctional regions of the cells exposed to nonpulsatile flow. By comparison in cells exposed to pulsatile flow VE‐cadherin was absent from the cell periphery but was found diffusely throughout the cell. Actin, both stress fibre and cortical, was absent from these cells. These results show that reassembly of the adherens junction, with a return of VE‐cadherin to cell‐cell contacts and a reformation of the actin cytoskeleton, is only seen in cells that have been exposed to nonpulsatile flow. Further work will show whether such adaptations are merely delayed under pulsatile flow or are prevented from occurring entirely. This study highlights the importance of using pulsatile flow when studying endothelial behaviour. The financial support of EPSRC and Sulzer Vascutek Ltd is gratefully acknowledged.