scholarly journals Passage dependent changes in nuclear and cytoskeleton structures of endothelial cells under laminar shear stress or cyclic stretch

2021 ◽  
Vol 7 (7) ◽  
pp. 327
Author(s):  
Yizhi Jiang ◽  
Nathaniel Witt ◽  
Julie Y. Ji
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Laminar Flow ◽  
Image Data ◽  
Cyclic Strain ◽  
Cyclic Stretch ◽  
Mechanical Stimuli ◽  
Laminar Shear Stress ◽  
External Forces ◽  
Induced Changes

<p class="abstract"><strong>Background:</strong> The ability of vascular endothelium to sense and respond to the mechanical stimuli generated by blood flow is pivotal in maintaining arterial homeostasis. A steady laminar flow tends to provide athero-protective effect via regulating endothelial functions, vascular tone, and further remodeling process. As arterial aging appeared to be an independent risk factor of cardiovascular diseases, it is critical to understand the effects of cell senescence on endothelial dysfunction under dynamic mechanical stimuli.</p><p class="abstract"><strong>Methods:</strong> In this study, we investigated the morphological responses of aortic endothelial cells toward laminar flow or cyclic stretch. Automated image recognition methods were applied to analyze image data to avoid bias. Differential patterns of morphological adaptations toward distinct mechanical stimuli were observed, and the shear-induced changes were found to be more associated with cell passages than that of cyclic strain.  </p><p class="abstract"><strong>Results:</strong> Our results demonstrated that the cytoskeleton and nuclear structural adaptations in endothelial cells toward laminar flow were altered over prolonged culture, suggesting that the failure of senescent endothelial cells to adapt to the applied shear stress morphologically could be one of the contributors to endothelial dysfunctions during vascular aging.</p><p class="abstract"><strong>Conclusions:</strong> Results indicated that cells were able to adjust their cytoskeleton and nuclear alignment and nuclear shapes in response to the applied mechanical stimuli, and that the shear-induced changes were more dependent on PD levels, where cells with higher PDL were more responsive to external forces.</p>

scholarly journals Primary cilia of human endothelial cells disassemble under laminar shear stress

2004 ◽  
Vol 164 (6) ◽  
pp. 811-817 ◽  
Author(s):  
Carlo Iomini ◽  
Karla Tejada ◽  
Wenjun Mo ◽  
Heikki Vaananen ◽  
Gianni Piperno
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Primary Cilia ◽  
Umbilical Vein ◽  
Intraflagellar Transport ◽  
Mechanical Stimuli ◽  
Laminar Shear Stress ◽  
Human Endothelial Cells ◽  
Umbilical Vein Endothelial Cells ◽  
Laminar Shear

We identified primary cilia and centrosomes in cultured human umbilical vein endothelial cells (HUVEC) by antibodies to acetyl-α-tubulin and capillary morphogenesis gene-1 product (CMG-1), a human homologue of the intraflagellar transport (IFT) protein IFT-71 in Chlamydomonas. CMG-1 was present in particles along primary cilia of HUVEC at interphase and around the oldest basal body/centriole at interphase and mitosis. To study the response of primary cilia and centrosomes to mechanical stimuli, we exposed cultured HUVEC to laminar shear stress (LSS). Under LSS, all primary cilia disassembled, and centrosomes were deprived of CMG-1. We conclude that the exposure to LSS ends the IFT in cultured endothelial cells.

Abstract 255: Laminar Shear Stress Enhances the Activity and Localization of RNA Polymerase II on the eNOS Gene

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Martina Weber ◽  
Jeffrey P Moore ◽  
Charles D Searles
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Fold Increase ◽  
Mrna Processing ◽  
Enos Gene ◽  
Laminar Shear Stress ◽  
Enos Mrna ◽  
Rnap Ii ◽  
Induced Changes ◽  
Laminar Shear

We have previously found that laminar shear enhances eNOS mRNA stability and translation by altering endothelial NO synthase (eNOS) mRNA 3′ polyadenylation. Transcription is tightly coupled to pre-mRNA processing, and is coordinated by RNA polymerase (RNAP) II. We assessed whether laminar shear stress alters the activity and localization of RNAP II on the eNOS gene. We found that endothelial cells exposed to laminar shear stress had a 2-fold (n=3, p < 0.05) increase in total RNAP II protein levels compared to control; this effect was dose-dependent (0–15 dynes/cm2). Since three different RNAP II phosphoisoforms are associated with different stages of mRNA synthesis, we examined whether shear stress affected protein expression of these particular phosphoisoforms. We found that cells exposed to laminar shear had a 3-fold increase (p<0.05) in expression of RNAP II phosphorylated at serine 2, which is associated with transcription elongation and 3′ polyadenylation. In contrast, shear stress did not alter expression of the other phosphoisoforms. We performed chromatin immunoprecipitation (ChIP) analysis to examine shear-induced changes in RNAP II localization on the eNOS gene. Using antibody against total RNAP II, eNOS sequences along the entire gene were amplified. Using the phosphoserine 2 specific RNAP II antibody, we found active RNAP II predominantly bound to the 3′UTR (exon 26) and downstream sequence of eNOS in sheared cells. These findings were confirmed by quantitative ChIP (3 fold increase, n = 8, p = 0.0378). This suggests that shear-induced changes in RNAP II phosphorylation enhance its ability to polyadenylate eNOS mRNA. Serine 2 phosphorylation is dependent on cyclin-dependent kinase 9 (CDK 9), and shear-induced recruitment of CDK 9 to the eNOS gene was examined. We found that endothelial cells exposed to laminar shear had enhanced localization of CDK 9 to the eNOS promoter and exons 8 and 22, and diminished localizationto exon 26 and in the downstream sequence. This indicates that shear recruits CDK 9 while RNAP II is bound to the promoter and early exons to activate RNAP by phosphorylating serine 2. In conclusion, laminar shear stress enhances eNOS mRNA processing and increases gene expression through recruitment of CDK 9 and activation of RNAP II.

Effect of Combined Cyclic Stretch and Fluid Shear Stress on Endothelial Cell Morphological Responses

2005 ◽  
Vol 127 (3) ◽  
pp. 374-382 ◽  
Author(s):  
Tomas B. Owatverot ◽  
Sara J. Oswald ◽  
Yong Chen ◽  
Jeremiah J. Wille ◽  
Frank C-P Yin
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Time Course ◽  
Fluid Shear Stress ◽  
Cyclic Stretch ◽  
Mechanical Stimuli ◽  
Cell Orientation ◽  
Fluid Shear ◽  
Aortic Endothelial Cells

Endothelial cells in vivo are normally subjected to multiple mechanical stimuli such as stretch and fluid shear stress (FSS) but because each stimulus induces magnitude-dependent morphologic responses, the relative importance of each stimulus in producing the normal in vivo state is not clear. Using cultured human aortic endothelial cells, this study first determined equipotent levels of cyclic stretch, steady FSS, and oscillatory FSS with respect to the time course of cell orientation. We then tested whether these levels of stimuli were equipotent in combination with each other by imposing simultaneous cyclic stretch and steady FSS or cyclic stretch and oscillatory FSS so as to reinforce or counteract the cells’ orientation responses. Equipotent levels of the three stimuli were 2% cyclic stretch at 2%∕s, 80dynes∕cm2 steady FSS and 20±10dynes∕cm2 oscillatory FSS at 20dyne∕cm2-s. When applied in reinforcing fashion, cyclic stretch and oscillatory, but not steady, FSS were additive. Both pairs of stimuli canceled when applied in counteracting fashion. These results indicate that this level of cyclic stretch and oscillatory FSS sum algebraically so that they are indeed equipotent. In addition, oscillatory FSS is a stronger stimulus than steady FSS for inducing cell orientation. Moreover, arterial endothelial cells in vivo are likely receiving a stronger stretch than FSS stimulus.

Supernatant of endothelial cells exposed to laminar flow inhibits mesangial cell proliferation

1993 ◽  
Vol 264 (4) ◽  
pp. C1080-C1083 ◽  
Author(s):  
M. Morigi ◽  
C. Zoja ◽  
M. Figliuzzi ◽  
G. Remuzzi ◽  
A. Remuzzi
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Cell ◽  
Laminar Flow ◽  
Culture Medium ◽  
Fetal Calf Serum ◽  
Mesangial Cell ◽  
Calf Serum ◽  
Thymidine Uptake ◽  
Laminar Shear Stress

We investigated the effects of culture medium conditioned with endothelial cells exposed to hemodynamic shear forces on modulation of mesangial cell (MC) growth. Confluent monolayers of bovine aortic endothelial cells, grown in medium containing 10% fetal calf serum, were exposed to static or to laminar flow conditions for 24 h using a cone-and-plate device. Endothelial cell-conditioned medium was used to study the growth of bovine MC by [3H]thymidine uptake. The proliferative response of MC to fresh medium (containing 10% fetal calf serum) and to culture medium from endothelial cells under static flow [66.7 +/- 34.1 vs. 73.9 +/- 30.0 counts/min (cpm) x 10(-3)] was comparable. In contrast, medium conditioned with endothelial cells exposed to laminar shear stress of 8 dyn/cm2 almost completely abolished MC proliferation (5.8 +/- 6.9 cpm x 10(-3), P < 0.01). To establish whether this effect is due to endothelial cell production of a substance that inhibits MC proliferation or simply to metabolization of serum growth factors in the culture medium, we performed shear stress experiments using serum free medium and we added 10% fetal calf serum after shear exposure just before the proliferation assay. In this condition a significant antiproliferative effect of endothelial cell supernatant under laminar flow was obtained (27.7 +/- 23.4 vs. 68.8 +/- 45.8 cpm x 10(-3), laminar vs. static, P < 0.05), suggesting that endothelial cells under shear stress effectively produce a factor that inhibits MC proliferation. These results would suggest that local glomerular capillary blood flow could play a role in the regulation of MC mitogenesis.

The molecular mechanism of mechanotransduction in vascular homeostasis and disease

2020 ◽  
Vol 134 (17) ◽  
pp. 2399-2418
Author(s):  
Yoshito Yamashiro ◽  
Hiromi Yanagisawa
Keyword(s):  
Shear Stress ◽  
Blood Vessels ◽  
Vessel Wall ◽  
Vascular Diseases ◽  
Cell Interactions ◽  
Aortic Aneurysms ◽  
Cyclic Stretch ◽  
Mechanical Stimuli ◽  
Vascular Homeostasis ◽  
Matrix Cell

Abstract Blood vessels are constantly exposed to mechanical stimuli such as shear stress due to flow and pulsatile stretch. The extracellular matrix maintains the structural integrity of the vessel wall and coordinates with a dynamic mechanical environment to provide cues to initiate intracellular signaling pathway(s), thereby changing cellular behaviors and functions. However, the precise role of matrix–cell interactions involved in mechanotransduction during vascular homeostasis and disease development remains to be fully determined. In this review, we introduce hemodynamics forces in blood vessels and the initial sensors of mechanical stimuli, including cell–cell junctional molecules, G-protein-coupled receptors (GPCRs), multiple ion channels, and a variety of small GTPases. We then highlight the molecular mechanotransduction events in the vessel wall triggered by laminar shear stress (LSS) and disturbed shear stress (DSS) on vascular endothelial cells (ECs), and cyclic stretch in ECs and vascular smooth muscle cells (SMCs)—both of which activate several key transcription factors. Finally, we provide a recent overview of matrix–cell interactions and mechanotransduction centered on fibronectin in ECs and thrombospondin-1 in SMCs. The results of this review suggest that abnormal mechanical cues or altered responses to mechanical stimuli in EC and SMCs serve as the molecular basis of vascular diseases such as atherosclerosis, hypertension and aortic aneurysms. Collecting evidence and advancing knowledge on the mechanotransduction in the vessel wall can lead to a new direction of therapeutic interventions for vascular diseases.

STRETCHABLE Lab-on-Chip Device With Impedance Spectroscopy Capability for Mammalian Cell Studies

2016 ◽  
Author(s):  
Xudong Zhang ◽  
Anis Nurashikin Nordin ◽  
Fang Li ◽  
Ioana Voiculescu
Keyword(s):  
Impedance Spectroscopy ◽  
Mammalian Cells ◽  
Dynamic Environment ◽  
Cyclic Strain ◽  
Cyclic Stretch ◽  
Mechanical Stimuli ◽  
Aortic Endothelial Cells ◽  
Lab On Chip

This paper presents the fabrication and testing of electric cell-substrate impedance spectroscopy (ECIS) electrodes on a stretchable membrane. This is the first time when ECIS electrodes were fabricated on a stretchable substrate and ECIS measurements on mammalian cells exposed to cyclic strain of 10% were successfully demonstrated. A chemical was used to form strong chemical bond between gold electrodes of ECIS sensor and polymer membrane, which enable the electrodes keep good conductive ability during cyclic stretch. The stretchable membrane integrated with the ECIS sensor can simulate and replicate the dynamic environment of organism and enable the analysis of the cells activity involved in cells attachment and proliferation in vitro. Bovine aortic endothelial cells (BAEC) were used to evaluate the endothelial function influenced by mechanical stimuli in this research because they undergo in vivo cyclic physiologic elongation produced by the blood circulation in the arteries.

Laminar Flow on Endothelial Cells Suppresses eNOS O-GlcNAcylation to Promote eNOS Activity

2021 ◽  
Author(s):  
Sarah Basehore ◽  
Samantha Bohlman ◽  
Callie Weber ◽  
Swathi Swaminathan ◽  
Yuji Zhang ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Laminar Flow ◽  
No Production ◽  
Disturbed Flow ◽  
Enos Activity ◽  
Enos Phosphorylation ◽  
Steady Laminar ◽  
In Cells

Rationale: In diabetic animals as well as high glucose cell culture conditions, endothelial nitric oxide synthase (eNOS) is heavily O-GlcNAcylated, which inhibits its phosphorylation and nitric oxide (NO) production. It is unknown, however, whether varied blood flow conditions, which affect eNOS phosphorylation, modulate eNOS activity via O-GlcNAcylation-dependent mechanisms. Objective: The goal of this study was to test if steady laminar flow, but not oscillating disturbed flow, decreases eNOS O-GlcNAcylation, thereby elevating eNOS phosphorylation and NO production. Methods and Results: Human umbilical vein endothelial cells (HUVEC) were exposed to either laminar flow (20 dynes/cm2 shear stress) or oscillating disturbed flow (4{plus minus}6 dynes/cm2 shear stress) for 24 hours in a cone-and-plate device. eNOS O-GlcNAcylation was almost completely abolished in cells exposed to steady laminar but not oscillating disturbed flow. Interestingly, there was no change in protein level or activity of key O-GlcNAcylation enzymes (OGT, OGA, or GFAT). Instead, metabolomics data suggest that steady laminar flow decreases glycolysis and hexosamine biosynthetic pathway (HBP) activity, thereby reducing UDP-GlcNAc pool size and consequent O-GlcNAcylation. Inhibition of glycolysis via 2-deoxy-2-glucose (2-DG) in cells exposed to disturbed flow efficiently decreased eNOS O-GlcNAcylation, thereby increasing eNOS phosphorylation and NO production. Finally, we detected significantly higher O-GlcNAcylated proteins in endothelium of the inner aortic arch in mice, suggesting that disturbed flow increases protein O-GlcNAcylation in vivo. Conclusions: Our data demonstrate that steady laminar but not oscillating disturbed flow decreases eNOS O-GlcNAcylation by limiting glycolysis and UDP-GlcNAc substrate availability, thus enhancing eNOS phosphorylation and NO production. This research shows for the first time that O-GlcNAcylation is regulated by mechanical stimuli, relates flow-induced glycolytic reductions to macrovascular disease, and highlights targeting HBP metabolic enzymes in endothelial cells as a novel therapeutic strategy to restore eNOS activity and prevent EC dysfunction in cardiovascular disease.

scholarly journals Fluid shear stress modulates surface expression of adhesion molecules by endothelial cells

Blood ◽  
1995 ◽  
Vol 85 (7) ◽  
pp. 1696-1703 ◽  
Author(s):  
M Morigi ◽  
C Zoja ◽  
M Figliuzzi ◽  
M Foppolo ◽  
G Micheletti ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Laminar Flow ◽  
Fluid Shear Stress ◽  
Leukocyte Adhesion ◽  
Interleukin 1 ◽  
Static Condition ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Interleukin 1 Beta

We investigated the effect of hemodynamic shear forces on the expression of adhesive molecules, E-selectin, and intercellular adhesion molecule-1 (ICAM-1) on human umbilical vein endothelial cells (HUVEC) exposed to laminar (8 dynes/cm2) or turbulent shear stress (8.6 dynes/cm2 average), or to a static condition. Laminar flow induced a significant time-dependent increase in the surface expression of ICAM-1, as documented by flow cytometry studies. Endothelial cell surface expression of ICAM-1 in supernatants of HUVEC exposed to laminar flow was not modified, excluding the possibility that HUVEC exposed to laminar flow synthetize factors that upregulate ICAM-1. The effect of laminar flow was specific for ICAM-1, while E-selectin expression was not modulated by the flow condition. Turbulent flow did not affect surface expression of either E-selectin or ICAM-1. To evaluate the functional significance of the laminar-flow-induced increase in ICAM-1 expression, we studied the dynamic interaction of total leukocyte suspension with HUVEC exposed to laminar flow (8 dynes/cm2 for 6 hours) in a parallel-plate flow chamber or to static condition. Leukocyte adhesion to HUVEC pre-exposed to flow was significantly enhanced, compared with HUVEC maintained in static condition (233 +/- 67 v 43 +/- 16 leukocytes/mm2, respectively), and comparable with that of interleukin-1 beta treated HUVEC. Mouse monoclonal antibody anti-ICAM-1 completely blocked flow-induced upregulation of leukocyte adhesion. Interleukin-1 beta, which upregulated E-selectin expression, caused leukocyte rolling on HUVEC that was significantly lower on flow- conditioned HUVEC and almost absent on untreated static endothelial cells. Thus, laminar flow directly and selectively upregulates ICAM-1 expression on the surface of endothelial cells and promotes leukocyte adhesion. These data are relevant to the current understanding of basic mechanisms that govern local inflammatory reactions and tissue injury.

Laminar shear stress promotes mitochondrial homeostasis in endothelial cells

2018 ◽  
Vol 233 (6) ◽  
pp. 5058-5069 ◽  
Author(s):  
Li-Hong Wu ◽  
Hao-Chun Chang ◽  
Pei-Ching Ting ◽  
Danny L. Wang
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Laminar Shear Stress ◽  
Mitochondrial Homeostasis ◽  
Laminar Shear

A Promoter Polymorphism Regulates NFKB1 Gene Transactivity in Human Endothelial Cells under Laminar Shear Stress

2006 ◽  
Vol 38 (Supplement) ◽  
pp. S4
Author(s):  
Joon Y. Park ◽  
Iain K. Farrance ◽  
Hanjoong Jo ◽  
Steven R. Brant ◽  
Stephen M. Roth ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Promoter Polymorphism ◽  
Laminar Shear Stress ◽  
Human Endothelial Cells ◽  
Laminar Shear
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