Differential responses of the Nrf2-Keap1 system to laminar and oscillatory shear stresses in endothelial cells. VOLUME 280 (2005) PAGES 27244-27250

AbstractAtherosclerosis is a long-term disease process of the vascular system that is characterized by the formation of atherosclerotic plaques, which are inflammatory regions on medium and large-sized arteries. There are many factors contributing to plaque formation, such as changes in shear stress levels, rupture of endothelial cells, accumulation of lipids, and recruitment of leukocytes. Shear stress is one of the main factors that regulates the homeostasis of the circulatory system; therefore, sudden and chronic changes in shear stress may cause severe pathological conditions. In this study, microfluidic channels with cavitations were designed to mimic the shape of the atherosclerotic blood vessel, where the shear stress and pressure difference depend on design of the microchannels. Changes in the inflammatory-related molecules ICAM-1 and IL-8 were investigated in THP-1 cells in response to applied shear stresses in an continuous cycling system through microfluidic channels with periodic cavitations. ICAM-1 mRNA expression and IL-8 release were analyzed by qRT-PCR and ELISA, respectively. Additionally, the adhesion behavior of sheared THP-1 cells to endothelial cells was examined by fluorescence microscopy. The results showed that 15 Pa shear stress significantly increases expression of ICAM-1 gene and IL-8 release in THP-1 cells, whereas it decreases the adhesion between THP-1 cells and endothelial cells.

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L-Selectin–Dependent Leukocyte Adhesion to Microvascular But Not to Macrovascular Endothelial Cells of the Human Coronary System

Blood ◽

10.1182/blood.v89.9.3228 ◽

1997 ◽

Vol 89 (9) ◽

pp. 3228-3235 ◽

Cited By ~ 45

Author(s):

A. Zakrzewicz ◽

M. Gräfe ◽

D. Terbeek ◽

M. Bongrazio ◽

W. Auch-Schwelk ◽

...

Keyword(s):

Endothelial Cells ◽

Time Course ◽

Leukocyte Adhesion ◽

Flow Chamber ◽

Shear Stresses ◽

Selectin Ligands ◽

Tnf Α ◽

Factor Α

Abstract To characterize L-selectin–dependent cell adhesion to human vascular endothelium, human cardiac microvascular endothelial cells (HCMEC) and human coronary endothelial cells (HCEC) were isolated from explanted human hearts. The adhesion behavior of human (NALM-6) and mouse (300.19) pre-B cells transfected with cDNA encoding for human L-selectin was compared with that of the respective nontransfected cells in a flow chamber in vitro. More than 80% of the adhesion to tumor necrosis factor-α (TNF-α)–stimulated HCMEC at shear stresses <2 dyne/cm2 was L-selectin dependent and could be equally well blocked by an anti–L-selectin antibody or a L-selectin-IgG-chimera. No L-selectin dependent adhesion to HCEC could be shown. The L-selectin dependent adhesion to HCMEC was insensitive to neuraminidase, but greatly inhibited by addition of NaClO3 , which inhibits posttranslational sulfation and remained elevated for at least 24 hours of stimulation. E-selectin dependent adhesion of HL60 cells to HCMEC was blocked by neuraminidase, but not by NaClO3 and returned to control levels within 18 hours of HCMEC stimulation. It is concluded that microvascular, but not macrovascular endothelial cells express TNF-α–inducible sulfated ligand(s) for L-selectin, which differ from known L-selectin ligands, because sialylation is not required. The prolonged time course of L-selectin dependent adhesion suggests a role in sustained leukocyte recruitment into inflammatory sites in vivo.

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Biomechanical Characterization of Endothelial Cells Exposed to Shear Stress Using Acoustic Force Spectroscopy

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2021.612151 ◽

2021 ◽

Vol 9 ◽

Author(s):

Giulia Silvani ◽

Valentin Romanov ◽

Charles D. Cox ◽

Boris Martinac

Keyword(s):

Mechanical Properties ◽

Endothelial Cells ◽

Shear Stress ◽

Actin Filament ◽

Force Spectroscopy ◽

Shear Stresses ◽

Cell Periphery ◽

Static Conditions ◽

Cells Cultured ◽

Cell Cell

Characterizing mechanical properties of cells is important for understanding many cellular processes, such as cell movement, shape, and growth, as well as adaptation to changing environments. In this study, we explore the mechanical properties of endothelial cells that form the biological barrier lining blood vessels, whose dysfunction leads to development of many cardiovascular disorders. Stiffness of living endothelial cells was determined by Acoustic Force Spectroscopy (AFS), by pull parallel multiple functionalized microspheres located at the cell-cell periphery. The unique configuration of the acoustic microfluidic channel allowed us to develop a long-term dynamic culture protocol exposing cells to laminar flow for up to 48 h, with shear stresses in the physiological range (i.e., 6 dyn/cm2). Two different Endothelial cells lines, Human Aortic Endothelial Cells (HAECs) and Human Umbilical Vein Endothelial Cells (HUVECs), were investigated to show the potential of this tool to capture the change in cellular mechanical properties during maturation of a confluent endothelial monolayer. Immunofluorescence microscopy was exploited to follow actin filament rearrangement and junction formation over time. For both cell types we found that the application of shear-stress promotes the typical phenotype of a mature endothelium expressing a linear pattern of VE-cadherin at the cell-cell border and actin filament rearrangement along the perimeter of Endothelial cells. A staircase-like sequence of increasing force steps, ranging from 186 pN to 3.5 nN, was then applied in a single measurement revealing the force-dependent apparent stiffness of the membrane cortex in the kPa range. We also found that beads attached to cells cultured under dynamic conditions were harder to displace than cells cultured under static conditions, showing a stiffer membrane cortex at cell periphery. All together these results demonstrate that the AFS can identify changes in cell mechanics based on force measurements of adherent cells under conditions mimicking their native microenvironment, thus revealing the shear stress dependence of the mechanical properties of neighboring endothelial cells.

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Abstract 363: Lim Domain Only 4 Is a Shear-Sensitive Protein, Playing a Critical Role in Endothelial Inflammation and Atherosclerosis

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.32.suppl_1.a363 ◽

2012 ◽

Vol 32 (suppl_1) ◽

Author(s):

Wakako Takabe ◽

Chih-Wen Ni ◽

Dong Ju Son ◽

Noah Alberts-Grill ◽

Hanjoong Jo

Keyword(s):

Endothelial Cells ◽

Shear Stress ◽

Critical Role ◽

Oscillatory Shear ◽

Lim Domain ◽

Disturbed Flow ◽

Endothelial Inflammation ◽

And Migration ◽

Oscillatory Shear Stress ◽

Stable Flow

Recently, we have shown that disturbed flow, characterized by low and oscillatory shear stress, caused by a partial ligation of mouse left carotid artery (LCA) rapidly induces atherosclerosis. Using the partial ligation model and genome-wide microarray study with aortic endothelial RNAs obtained directly from the flow-disturbed carotid arteries, we previously identified mechanosensitive genes in mouse endothelial RNA including LIM domain only 4 ( lmo4 ). Here we report that LMO4 is a shear-sensitive protein that regulates endothelial inflammation. Lmo4 was up-regulated by disturbed flow in mouse LCA compared to the contralateral right CA (RCA) exposed to stable flow. At protein levels, LMO4 expression was significantly higher not only in LCA in our surgical model but also in the lesser curvature (flow-disturbed and athero-prone region of mouse aortic arch) compared to the greater curvature (stable-flow and ather-protected region). In addition, immunohistochemical staining of LMO4 in human coronary arteries revealed that its expression is detectable only in intimal endothelial cells, but not in medial cells. While LMO4 is known as a potential oncogene and associated with growth, migration and invasion of breast cancer cells, its role in cardiovascular system is not known to our knowledge. We tested a hypothesis that LMO4 is a mechanosensitive gene and plays a critical role in regulation of endothelial cell biology. LMO4 protein expression was robustly induced by oscillatory shear stress (OS) compared to laminar shear (LS) in human umbilical vein endothelial cells (HUVEC). Treatment of HUVEC with siRNA against LMO4 significantly inhibited OS-induced inflammation and migration, but not apoptosis and cell cycle progression. Further, LMO4 siRNA treatment significantly blunted expression of VCAM-1 and interleukin-8 induced by OS in endothelial cells. These results suggest that LMO4 is a shear-induced gene that plays a critical role in OS-induced endothelial inflammation and migration, and potentially in atherosclerosis.

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Integrated microfluidic chip for endothelial cells culture and analysis exposed to a pulsatile and oscillatory shear stress

Lab on a Chip ◽

10.1039/b909312e ◽

2009 ◽

Vol 9 (21) ◽

pp. 3118 ◽

Cited By ~ 94

Author(s):

Jianbo Shao ◽

Lei Wu ◽

Jianzhang Wu ◽

Yunhuan Zheng ◽

Hui Zhao ◽

...

Keyword(s):

Endothelial Cells ◽

Shear Stress ◽

Microfluidic Chip ◽

Oscillatory Shear ◽

Oscillatory Shear Stress

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Effects of Fluid Shear Stress on Endothelial Cell Invasion Into Three-Dimensional Matrices

ASME 2007 Summer Bioengineering Conference ◽

10.1115/sbc2007-176207 ◽

2007 ◽

Author(s):

Hojin Kang ◽

Kayla J. Bayless ◽

Roland Kaunas

Keyword(s):

Endothelial Cells ◽

Shear Stress ◽

Endothelial Cell ◽

Cell Invasion ◽

Fluid Shear Stress ◽

Vascular Endothelial Cells ◽

Umbilical Vein ◽

Shear Stresses ◽

Collagen Gels ◽

Fluid Shear

We have previously developed a cell culture model to study the effects of angiogenic factors, such as sphingosine-1-phosphate (S1P), on the invasion of endothelial cells into the underlying extracellular matrix. In addition to biochemical stimuli, vascular endothelial cells are subjected to fluid shear stress due to blood flow. The present study is aimed at determining the effects of fluid shear stress on endothelial cell invasion into collagen gels. A device was constructed to apply well-defined fluid shear stresses to confluent human umbilical vein endothelial cells (HUVECs) seeded on collagen gels. Fluid shear stress induced significant increases in cell invasion with a maximal induction at ∼5 dyn/cm2. These results provide evidence that fluid shear stress is a significant stimulus for endothelial cell invasion and may play a role in regulating angiogenesis.

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Non-Invasive Molecular Imaging of Shear Stress-Induced Endothelial Activation and Atherosclerotic Plaque Vulnerability

ASME 2012 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2012-80515 ◽

2012 ◽

Author(s):

K. Van der Heiden ◽

H. C. Groen ◽

P. C. Evans ◽

L. Speelman ◽

F. Gijsen ◽

...

Keyword(s):

Endothelial Cells ◽

Shear Stress ◽

Atherosclerotic Lesion ◽

Oscillatory Shear ◽

Lesion Development ◽

Non Invasive ◽

Oscillatory Shear Stress ◽

The Relationship ◽

Atherosclerotic Lesion Development

Atherosclerosis is a lipid- and inflammation driven disease of the larger arteries and is found at specific locations in the arterial tree, i.e. at branches and bends where endothelial cells are exposed to low and low, oscillatory shear stress. Shear stress, the frictional force acting on the endothelial cells as a result of the blood flow, affects endothelial physiology. It determines the location of atherosclerotic lesion development as low and low, oscillatory shear stress induce pro-inflammatory transcription factors but reduce expression and/or activity of anti-inflammatory transcription factors in endothelial cells, rendering the vascular wall vulnerable for inflammation. Consequently, in the presence of atherosclerotic risk factors, such as hypercholesterolemia and diabetes, atherosclerotic lesion development can occur. Although the relationship between low and low, oscillatory shear stress and the prevalence of atherosclerosis has been recognized for several decades, insight into the mechanisms underlying this relationship is still incomplete. The correlation between shear stress and endothelial inflammation was demonstrated by in vitro experiments, in which cultured endothelial cells were exposed to specific flow profiles, and confirmed in vivo by gene expression pattern studies at atherosclerosis-susceptible sites. However, the relationship was not substantiated by direct causal in vivo evidence. Therefore, we developed a method to change the local shear stress field in mice in vivo and studied its effect on the endothelial molecular pathways and resulting atherosclerotic plaque formation. Moreover it allowed us to develop non-invasive molecular imaging strategies to detect vulnerable plaques.

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