Effect of shear stress upon localization of the Golgi apparatus and microtubule organizing center in isolated cultured endothelial cells

1993 ◽  
Vol 104 (4) ◽  
pp. 1145-1153 ◽  
Author(s):  
D.E. Coan ◽  
A.R. Wechezak ◽  
R.F. Viggers ◽  
L.R. Sauvage
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Cell Migration ◽  
Golgi Apparatus ◽  
Flow Direction ◽  
Microtubule Organizing Center ◽  
Directed Cell Migration ◽  
Time Period ◽  
Significant Difference ◽  
Organizing Center

Despite substantial evidence to suggest that directed cell migration is dependent upon positioning of the Golgi apparatus (GA) and the microtubule organizing center (MTOC), some controversy exists about whether such a relationship is relevant to endothelial cells under flow. The present study was undertaken to provide an indepth investigation of the relationship between shear stress, GA/MTOC localization, cell migration and nuclear position. Bovine carotid endothelial cells were exposed to 22 or 88 dynes/cm2 for 0.5, 2, 8 or 24 h, and localization of their GA/MTOCs was determined relative to the direction of flow. In no-flow control specimens, (0, 0.5, 2, 8 and 24 h) there was no change in the equally distributed GA/MTOCs. In contrast, during the first 8 h at 88 dynes/cm2 and by 2 h at 22 dynes/cm2 there was a significant increase in the number of cells with GA/MTOCs localized upstream to flow direction. The effect was temporary, however, and by 24 h there was no significant difference between the no-flow, 22 and 88 dynes/cm2 specimens. Analysis of GA/MTOC localization with respect to the direction of cell migration determined that 72.5% of no-flow cells possessed GA/MTOCs localized to the sides of nuclei nearest the direction of migration. In contrast, 64% of the specimens shear stressed over the same time period had GA/MTOCs localized to the sides of nuclei opposite the direction of migration. These results suggest that positioning of the GA/MTOC in endothelial cells is not dependent completely upon the direction of migration.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Gαq/11-mediated intracellular calcium responses to retrograde flow in endothelial cells

2012 ◽  
Vol 303 (4) ◽  
pp. C467-C473 ◽  
Author(s):  
Benoît Melchior ◽  
John A. Frangos
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Fluid Shear Stress ◽  
Flow Direction ◽  
Cytosolic Calcium ◽  
Cell Junction ◽  
Retrograde Flow ◽  
Endoplasmic Reticulum Calcium ◽  
Time To Peak ◽  
Inositol 1,4,5 Trisphosphate

Disturbed flow patterns, including reversal in flow direction, are key factors in the development of dysfunctional endothelial cells (ECs) and atherosclerotic lesions. An almost immediate response of ECs to fluid shear stress is the increase in cytosolic calcium concentration ([Ca2+]i). Whether the source of [Ca2+]i is extracellular, released from Ca2+ intracellular stores, or both is still undefined, though it is likely dependent on the nature of forces involved. We have previously shown that a change in flow direction (retrograde flow) on a flow-adapted endothelial monolayer induces the remodeling of the cell-cell junction along with a dramatic [Ca2+]i burst compared with cells exposed to unidirectional or orthograde flow. The heterotrimeric G protein-α q and 11 subunit (Gαq/11) is a likely candidate in effecting shear-induced increases in [Ca2+]i since its expression is enriched at the junction and has been previously shown to be activated within seconds after onset of flow. In flow-adapted human ECs, we have investigated to what extent the Gαq/11 pathway mediates calcium dynamics after reversal in flow direction. We observed that the elapsed time to peak [Ca2+]i response to a 10 dyn/cm2 retrograde shear stress was increased by 11 s in cells silenced with small interfering RNA directed against Gαq/11. A similar lag in [Ca2+]i transient was observed after cells were treated with the phospholipase C (PLC)-βγ inhibitor, U-73122, or the phosphatidylinositol-specific PLC inhibitor, edelfosine, compared with controls. Lower levels of inositol 1,4,5-trisphosphate accumulation seconds after the onset of flow correlated with the increased lag in [Ca2+]i responses observed with the different treatments. In addition, inhibition of the inositol 1,4,5-trisphosphate receptor entirely abrogated flow-induced [Ca2+]i. Taken together, our results identify the Gαq/11-PLC pathway as the initial trigger for retrograde flow-induced endoplasmic reticulum calcium store release, thereby offering a novel approach to regulating EC dysfunctions in regions subjected to the reversal of blood flow.

Effects of Steady Spatial Wall Shear Stress Gradients on Endothelial Cell Morphology in Three-Dimensional Models

2007 ◽  
Author(s):  
Leonie Rouleau ◽  
Monica Farcas ◽  
Jean-Claude Tardif ◽  
Rosaire Mongrain ◽  
Richard Leask
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Cell ◽  
Wall Shear Stress ◽  
Cell Morphology ◽  
Flow Direction ◽  
Stress Gradient ◽  
Spatial Gradient ◽  
Stress Gradients ◽  
Wall Shear

Endothelial cell (EC) dysfunction has been linked to atherosclerosis through their response to hemodynamic forces. Flow in stenotic vessels creates complex spatial gradients in wall shear stress. In vitro studies examining the effect of shear stress on endothelial cells have used unrealistic and simplified models, which cannot reproduce physiological conditions. The objective of this study was to expose endothelial cells to the complex shear shear pattern created by an asymmetric stenosis. Endothelial cells were grown and exposed for different times to physiological steady flow in straight dynamic controls and in idealized asymmetric stenosis models. Cells subjected to 1D flow aligned with flow direction and had a spindle-like shape when compared to static controls. Endothelial cell morphology was noticeable different in the regions with a spatial gradient in wall shear stress, being more randomly oriented and of cobblestone shape. This occurred despite the presence of an increased magnitude in shear stress. No other study to date has described this morphology in the presence of a positive wall shear stress gradient or gradient of significant shear magnitude. This technique provides a more realistic model to study endothelial cell response to spatial and temporal shear stress gradients that are present in vivo and is an important advancement towards a better understanding of the mechanisms involved in coronary artery disease.

The Elongation and Orientation of Cultured Endothelial Cells in Response to Shear Stress

1985 ◽  
Vol 107 (4) ◽  
pp. 341-347 ◽  
Author(s):  
M. J. Levesque ◽  
R. M. Nerem
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Cell Elongation ◽  
Vascular Endothelial Cells ◽  
Flow Direction ◽  
Flow Chamber ◽  
Shear Stresses ◽  
Cell Alignment ◽  
Aortic Endothelial Cells ◽  
Time Required

Vascular endothelial cells appear to be aligned with the flow in the immediate vicinity of the arterial wall and have a shape which is more ellipsoidal in regions of high shear and more polygonal in regions of low shear stress. In order to study quantitatively the nature of this response, bovine aortic endothelial cells grown on Thermanox plastic coverslips were exposed to shear stress levels of 10, 30, and 85 dynes/cm2 for periods up to 24 hr using a parallel plate flow chamber. A computer-based analysis system was used to quantify the degree of cell elongation with respect to the change in cell angle of orientation and with time. The results show that (i) endothelial cells orient with the flow direction under the influence of shear stress, (ii) the time required for cell alignment with flow direction is somewhat longer than that required for cell elongation, (iii) there is a strong correlation between the degree of alignment and endothelial cell shape, and (iv) endothelial cells become more elongated when exposed to higher shear stresses.

scholarly journals Study of FRSN cells migration under the conditions of continuous low flow

2018 ◽  
pp. 144-147
Author(s):  
А.А. Московцев ◽  
Д.В. Колесов ◽  
А.Н. Мыльникова ◽  
А.А. Кубатиев
Keyword(s):  
Stem Cells ◽  
Shear Stress ◽  
Cell Migration ◽  
Fluid Flow ◽  
Flow Direction ◽  
The Body ◽  
Low Flow ◽  
Slip Mode ◽  
Stick Slip ◽  
Low Intensity

Поток жидкости оказывает значительное влияние на морфофункциональное состояние большинства клеток в организме. Это может проявляться в миграции клеток под действием сдвиговой деформации или градиента питательных веществ. Мезенхимные стволовые фибробластоподобные клетки FRSN были культивированы в условиях воздействия постоянного потока жидкости в микрофлюидном чипе. Проведены исследования миграции клеток на разных стадиях адгезии под действием потока в различных областях чипа. Обнаружены значительные перемещения клеток в режиме «stick-slip» вдоль направления потока. The fluid flow exerts a significant effect on most cells in the body. This effect can involve cell migration under the action of shear stress or nutrient gradient. FRSN mesenchymal stem cells were cultured under the action of a constant fluid flow of low intensity in a microfluidic chip. The study of cell migration at different stages of adhesion was performed under the action of flow in different areas of the chip. Significant cell movements in a stick-slip mode along the flow direction were observed.

3-D Stress Analysis in Cultured Endothelial Cells Exposed to Fluid Shear Stress

1999 ◽  
Author(s):  
T. Ohashi ◽  
H. Sugawara ◽  
Y. Ishii ◽  
M. Sato
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Cell ◽  
Cell Surface ◽  
Fluid Shear Stress ◽  
Flow Direction ◽  
Stress Distributions ◽  
Fluid Shear ◽  
Surface Geometry ◽  
Cultured Endothelial Cells

Abstract Under fluid shear stress, applied both in vivo and in vitro, vascular endothelial cells show morphological changes. After applying shear stress, cultured endothelial cells showed elongation and orientation to the flow direction (Kataoka et al., 1998). Moreover, statistical image analysis showed that intercellular F-actin distributions were confirmed to change depending on the shear stress and the flow direction. Thus, the endothelial cell morphology relates closely with the cytoskeletal structures. Intercellular stress distributions in the cells may be also accompanied by the reorganization of cytoskeletal structures. The use of both atomic force microscopy measurements (AFM) of endothelial cell surface topography and computational fluid dynamics of shear stress distributions acting on the cell surface, it has revealed that the surface geometry defined the detailed distribution of shear stress (Davies et al., 1995).

scholarly journals Distribution of microtubule organizing centers in migrating sheets of endothelial cells.

1981 ◽  
Vol 91 (2) ◽  
pp. 589-594 ◽  
Author(s):  
A I Gotlieb ◽  
L M May ◽  
L Subrahmanyan ◽  
V I Kalnins
Keyword(s):  
Endothelial Cells ◽  
Monolayer Culture ◽  
Cell Movement ◽  
Time Lapse ◽  
Microtubule Organizing Center ◽  
Organizing Center ◽  
Direction Of Movement ◽  
The Relationship ◽  
Wounded Area

This study was designed to investigate the relationship between the position of the microtubule organizing center (MTOC) and the direction of migration of a sheet of endothelial cells (EC). Using immunofluorescence and phase microscopy the MTOC's of migrating EC were visualized as the cells moved into an in vitro experimental wound produced by mechanical denudation of part of a confluent monolayer culture. Although the MTOC's in nonmigrating EC were randomly positioned in relation to the nucleus, in migrating cells the position of the MTOC's changed so that 80% of the cells had the MTOC positioned in front of the nucleus toward the direction of movement of the endothelial sheet. This repositioning of the MTOC occurred within the first 4 h after wounding and was associated with the beginning of migration of EC's into the wounded area as seen by time-lapse cinemicrophotography. These studies focus attention on the MTOC as a cytoskeletal structure that may play a role in determining the direction of cell movement.

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