Integrin mechanotransduction stimulates caveolin-1 phosphorylation and recruitment of Csk to mediate actin reorganization

2005 ◽  
Vol 288 (2) ◽  
pp. H936-H945 ◽  
Author(s):  
C. Radel ◽  
V. Rizzo
Keyword(s):  
Shear Stress ◽  
Dependent Manner ◽  
Laminar Shear Stress ◽  
Integrin Activation ◽  
Actin Reorganization ◽  
Aortic Endothelial Cells ◽  
Caveolin 1 ◽  
Domain Peptide ◽  
Mlc Phosphorylation

To identify the role of caveolin-1 in integrin mechanotransduction, we exposed bovine aortic endothelial cells to 10 dyn/cm2 of laminar shear stress. Caveolin-1 was acutely and transiently phosphorylated with shear, occurring downstream of β1-integrin activation as the β1-integrin blocking antibody JB1A was inhibitory. In manipulating Src family kinase (SFK) activity with knockdown of Csk or type 1 protein phosphatase (PP1) treatment, we observed coordinate increase and decrease in shear-induced caveolin-1 phosphorylation, respectively. Hence, shear-stimulated caveolin-1 phosphorylation is regulated by SFKs. Shear-induced recruitment and phosphorylation of caveolin-1 occurred at β1-integrin sites in a β1-integrin- and SFK-dependent manner. Csk, described to interact with pY14-caveolin-1 and integrins, bound to an increased pool of phosphorylated caveolin-1 after shear corresponding with elevated Csk at β1-integrin sites. Like caveolin-1, treatment with JB1A and PP1 attenuated shear-induced Csk association with β1-integrins. Csk function was assayed with transfection of a caveolin-1 phosphorylation domain peptide. The peptide attenuated shear-induced association of Csk at β1-integrin sites, as well as colocalization of Csk with paxillin and phosphorylated caveolin-1. Because integrin and Csk activity regulate cytoskeletal reorganization, we evaluated the role of this mechanism in shear-induced myosin light chain (MLC) phosphorylation. Knockdown of Csk expression was sufficient to reduce MLC diphosphorylation due to shear. Disruption of Csk-integrin association by peptide treatment was also inhibitory of the MLC diphosphorylation response. Together these data indicate that integrin activation with shear stress results in SFK-regulated caveolin-1 phosphorylation that, in turn, mediates Csk association at integrin sites, where it plays a role in downstream, shear-stimulated MLC diphosphorylation.

Abstract 927: The Role Of Peroxiredoxins As Mechanosensitive Antioxidants In Endothelial Cells

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Amy Mowbray ◽  
Sang Won Kang ◽  
Sue Goo Rhee ◽  
Hanjoong Jo
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Subcellular Localization ◽  
Molecular Mechanisms ◽  
Immunofluorescent Staining ◽  
Dependent Manner ◽  
Laminar Shear Stress ◽  
Arterial Tree ◽  
Aortic Endothelial Cells ◽  
Stress Dependent

Atherosclerosis is an inflammatory disease occurring primarily in curved or branching regions of the arterial tree where disturbed flow patterns, such as oscillation, exist. We have previously shown that oscillatory shear stress (OS) increases reactive oxygen species (ROS) levels in endothelial cells, while laminar shear stress (LS) reduces ROS compared to static controls. OS stimulation of ROS has been shown to occur in an NADPH oxidase-dependent manner. However, the mechanism by which LS removes ROS remains unclear. Peroxiredoxins (PRX) are a family of antioxidant proteins that have been linked to the prevention of oxidative stress and inflammation, but their role in atherosclerosis is unknown. Here, we hypothesize that shear stress regulates ROS levels in endothelial cells by controlling antioxidant peroxiredoxins. To test this hypothesis, bovine aortic endothelial cells (BAEC) were subjected to static, laminar, and oscillatory fluid flow conditions via cone-and-plate viscometer. Western blot analysis and immunofluorescent staining were used to evaluate the expression and subcellular localization of six known mammalian peroxiredoxins (PRX I-VI). Immunoblots indicated that BAEC express all six isoforms of peroxiredoxin proteins and that LS upregulated PRX I levels significantly compared to static controls and OS. Immunofluorescence also showed a distinct subcellular localization of each PRX: PRX I, II, IV, V and VI in the cytoplasm, PRX I, IV and V in the Golgi, PRX III in the mitochondria, and PRX I in the nucleus. These results indicate that peroxiredoxins are mechanosensitive antioxidants, removing ROS in a subcellular-specific manner. Based on these data, we suggest that peroxiredoxin antioxidants are likely involved in the molecular mechanisms that control shear stress-dependent atherosclerotic plaque development.

Endothelial albumin permeability is shear dependent, time dependent, and reversible

1991 ◽  
Vol 260 (6) ◽  
pp. H1992-H1996 ◽  
Author(s):  
H. Jo ◽  
R. O. Dull ◽  
T. M. Hollis ◽  
J. M. Tarbell
Keyword(s):  
Shear Stress ◽  
Endothelial Cell ◽  
Fluorescein Isothiocyanate ◽  
Vascular Wall ◽  
Laminar Shear Stress ◽  
Aortic Endothelial Cells ◽  
Transendothelial Permeability ◽  
Steady Laminar Shear Stress ◽  
Laminar Shear

Altered permeability of vascular endothelium to macromolecules may play a role in vascular disease as well as vascular homeostasis. Because the shear stress of flowing blood on the vascular wall is known to influence many endothelial cell properties, an in vitro system to measure transendothelial permeability (Pe) to fluorescein isothiocyanate conjugated bovine serum albumin under defined physiological levels of steady laminar shear stress was developed. Bovine aortic endothelial cells grown on polycarbonate filters pretreated with gelatin and fibronectin constituted the model system. Onset of 1 dyn/cm2 shear stress resulted in a Pe rise from 5.1 +/- 1.3 x 10(-6) cm/s to 21.9 +/- 4.6 X 10(-6) cm/s at 60 min (n = 6); while 10 dyn/cm2 shear stress increased Pe from 4.8 +/- 1.5 X 10(-6) cm/s to 50.2 +/- 6.8 X 10(-6) cm/s at 30 min and 49.6 +/- 8.9 X 10(-6) cm/s at 60 (n = 9). Pe returned to preshear values within 120 and 60 min after removal of 1 and 10 dyn/cm2 shear stress, respectively. The data show that endothelial cell Pe in vitro is acutely sensitive to shear stress.

scholarly journals Shear stress augments mitochondrial ATP generation that triggers ATP release and Ca2+ signaling in vascular endothelial cells

2018 ◽  
Vol 315 (5) ◽  
pp. H1477-H1485 ◽  
Author(s):  
Kimiko Yamamoto ◽  
Hiromi Imamura ◽  
Joji Ando
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Vascular Endothelial Cells ◽  
Critical Role ◽  
Atp Release ◽  
Vascular Endothelial ◽  
The Novel ◽  
Caveolin 1 ◽  
Atp Generation

Vascular endothelial cells (ECs) sense and transduce hemodynamic shear stress into intracellular biochemical signals, and Ca2+ signaling plays a critical role in this mechanotransduction, i.e., ECs release ATP in the caveolae in response to shear stress and, in turn, the released ATP activates P2 purinoceptors, which results in an influx into the cells of extracellular Ca2+. However, the mechanism by which the shear stress evokes ATP release remains unclear. Here, we demonstrated that cellular mitochondria play a critical role in this process. Cultured human pulmonary artery ECs were exposed to controlled levels of shear stress in a flow-loading device, and changes in the mitochondrial ATP levels were examined by real-time imaging using a fluorescence resonance energy transfer-based ATP biosensor. Immediately upon exposure of the cells to flow, mitochondrial ATP levels increased, which was both reversible and dependent on the intensity of shear stress. Inhibitors of the mitochondrial electron transport chain and ATP synthase as well as knockdown of caveolin-1, a major structural protein of the caveolae, abolished the shear stress-induced mitochondrial ATP generation, resulting in the loss of ATP release and influx of Ca2+ into the cells. These results suggest the novel role of mitochondria in transducing shear stress into ATP generation: ATP generation leads to ATP release in the caveolae, triggering purinergic Ca2+ signaling. Thus, exposure of ECs to shear stress seems to activate mitochondrial ATP generation through caveola- or caveolin-1-mediated mechanisms. NEW & NOTEWORTHY The mechanism of how vascular endothelial cells sense shear stress generated by blood flow and transduce it into functional responses remains unclear. Real-time imaging of mitochondrial ATP demonstrated the novel role of endothelial mitochondria as mechanosignaling organelles that are able to transduce shear stress into ATP generation, triggering ATP release and purinoceptor-mediated Ca2+ signaling within the cells.

scholarly journals Microtubule disassembly increases endothelial cell barrier dysfunction: role of MLC phosphorylation

2001 ◽  
Vol 281 (3) ◽  
pp. L565-L574 ◽  
Author(s):  
Alexander D. Verin ◽  
Anna Birukova ◽  
Peiyi Wang ◽  
Feng Liu ◽  
Patrice Becker ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Electrical Resistance ◽  
Rho Gtpase ◽  
Dependent Manner ◽  
Transendothelial Electrical Resistance ◽  
Barrier Dysfunction ◽  
Microtubule Disruption ◽  
Barrier Regulation ◽  
Mlc Phosphorylation

Endothelial cell (EC) barrier regulation is critically dependent on cytoskeletal components (microfilaments and microtubules). Because several edemagenic agents induce actomyosin-driven EC contraction tightly linked to myosin light chain (MLC) phosphorylation and microfilament reorganization, we examined the role of microtubule components in bovine EC barrier regulation. Nocodazole or vinblastine, inhibitors of microtubule polymerization, significantly decreased transendothelial electrical resistance in a dose-dependent manner, whereas pretreatment with the microtubule stabilizer paclitaxel significantly attenuated this effect. Decreases in transendothelial electrical resistance induced by microtubule disruption correlated with increases in lung permeability in isolated ferret lung preparations as well as with increases in EC stress fiber content and MLC phosphorylation. The increases in MLC phosphorylation were attributed to decreases in myosin-specific phosphatase activity without significant increases in MLC kinase activity and were attenuated by paclitaxel or by several strategies (C3 exotoxin, toxin B, Rho kinase inhibition) to inhibit Rho GTPase. Together, these results suggest that microtubule disruption initiates specific signaling pathways that cross talk with microfilament networks, resulting in Rho-mediated EC contractility and barrier dysfunction.

Pattern formation of vascular smooth muscle cells subject to nonuniform fluid shear stress: role of PDGF-β receptor and Src

2003 ◽  
Vol 285 (3) ◽  
pp. H1081-H1090 ◽  
Author(s):  
Shu Q. Liu ◽  
Christopher Tieche ◽  
Dalin Tang ◽  
Paul Alkema
Keyword(s):  
Shear Stress ◽  
Smooth Muscle ◽  
Cell Density ◽  
Fluid Shear Stress ◽  
Density Gradients ◽  
Dependent Manner ◽  
Fluid Shear ◽  
Polymer Implants ◽  
Β Receptor

Blood vessels are subject to fluid shear stress, a hemodynamic factor that inhibits the mitogenic activities of vascular cells. The presence of nonuniform shear stress has been shown to exert graded suppression of cell proliferation and induces the formation of cell density gradients, which in turn regulate the direction of smooth muscle cell (SMC) migration and alignment. Here, we investigated the role of platelet-derived growth factor (PDGF)-β receptor and Src in the regulation of such processes. In experimental models with vascular polymer implants, SMCs migrated from the vessel media into the neointima of the implant under defined fluid shear stress. In a nonuniform shear model, blood shear stress suppressed the expression of PDGF-β receptor and the phosphorylation of Src in a shear level-dependent manner, resulting in the formation of mitogen gradients, which were consistent with the gradient of cell density as well as the alignment of SMCs. In contrast, uniform shear stress in a control model elicited an even influence on the activity of mitogenic molecules without modulating the uniformity of cell density and did not significantly influence the direction of SMC alignment. The suppression of the PDGF-β receptor tyrosine kinase and Src with pharmacological substances diminished the gradients of mitogens and cell density and reduced the influence of nonuniform shear stress on SMC alignment. These observations suggest that PDGF-β receptor and Src possibly serve as mediating factors in nonuniform shear-induced formation of cell density gradients and alignment of SMCs in the neointima of vascular polymer implants.

scholarly journals Competing Fluid Forces Control Endothelial Sprouting in a 3-D Microfluidic Vessel Bifurcation Model

Micromachines ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 451 ◽  
Author(s):  
Ehsan Akbari ◽  
Griffin B. Spychalski ◽  
Kaushik K. Rangharajan ◽  
Shaurya Prakash ◽  
Jonathan W. Song
Keyword(s):  
Shear Stress ◽  
Fluid Flow ◽  
Bifurcation Point ◽  
Flow Dynamics ◽  
Laminar Shear Stress ◽  
Local Flow ◽  
Fluid Forces ◽  
Sprouting Angiogenesis ◽  
Laminar Shear

Sprouting angiogenesis—the infiltration and extension of endothelial cells from pre-existing blood vessels—helps orchestrate vascular growth and remodeling. It is now agreed that fluid forces, such as laminar shear stress due to unidirectional flow in straight vessel segments, are important regulators of angiogenesis. However, regulation of angiogenesis by the different flow dynamics that arise due to vessel branching, such as impinging flow stagnation at the base of a bifurcating vessel, are not well understood. Here we used a recently developed 3-D microfluidic model to investigate the role of the flow conditions that occur due to vessel bifurcations on endothelial sprouting. We observed that bifurcating fluid flow located at the vessel bifurcation point suppresses the formation of angiogenic sprouts. Similarly, laminar shear stress at a magnitude of ~3 dyn/cm2 applied in the branched vessels downstream of the bifurcation point, inhibited the formation of angiogenic sprouts. In contrast, co-application of ~1 µm/s average transvascular flow across the endothelial monolayer with laminar shear stress induced the formation of angiogenic sprouts. These results suggest that transvascular flow imparts a competing effect against bifurcating fluid flow and laminar shear stress in regulating endothelial sprouting. To our knowledge, these findings are the first report on the stabilizing role of bifurcating fluid flow on endothelial sprouting. These results also demonstrate the importance of local flow dynamics due to branched vessel geometry in determining the location of sprouting angiogenesis.

scholarly journals Role of Myoendothelial Gap Junctions in the Regulation of Human Coronary Artery Smooth Muscle Cell Differentiation by Laminar Shear Stress

2016 ◽  
Vol 39 (2) ◽  
pp. 423-437 ◽  
Author(s):  
Zongqi Zhang ◽  
Yizhu Chen ◽  
Tiantian Zhang ◽  
Lingyu Guo ◽  
Wenlong Yang ◽  
...  
Keyword(s):  
Shear Stress ◽  
Smooth Muscle ◽  
Coronary Artery ◽  
Gap Junctions ◽  
Phenotypic Switching ◽  
Laminar Shear Stress ◽  
Human Coronary Artery ◽  
Laminar Shear ◽  
Synthetic Phenotype

Background/Aims: Smooth muscle cells may dedifferentiate into the synthetic phenotype and promote atherosclerosis. Here, we explored the role of myoendothelial gap junctions in phenotypic switching of human coronary artery smooth muscle cells (HCASMCs) co-cultured with human coronary artery endothelial cells (HCAECs) exposed to shear stress. Methods: HCASMCs and HCAECs were seeded on opposite sides of Transwell inserts, and HCAECs were exposed to laminar shear stress of 12 dyn/cm2 or 5 dyn/cm2. The myoendothelial gap junctions were evaluated by using a multi-photon microscope. Results: In co-culture with HCAECs, HCASMCs exhibited a contractile phenotype, and maintained the expression of differentiation markers MHC and H1-calponin. HCASMCs and HCAECs formed functional intercellular junctions, as evidenced by colocalization of connexin(Cx)40 and Cx43 on cellular projections inside the Transwell membrane and biocytin transfer from HCAECs to HCASMCs. Cx40 siRNA and 18-α-GA attenuated protein expression of MHC and H1-calponin in HCASMCs. Shear stress of 5 dyn/cm2 increased Cx43 and decreased Cx40 expression in HCAECs, and partly inhibited biocytin transfer from HCAECs to HCASMCs, which could be completely blocked by Cx43 siRNA or restored by Cx40 DNA transfected into HCAECs. The exposure of HCAECs to shear stress of 5 dyn/cm2 promoted HCASMC phenotypic switching, manifested by morphological changes, decrease in MHC and H1-calponin expression, and increase in platelet-derived growth factor (PDGF)-BB release, which was partly rescued by Cx43 siRNA or Cx40 DNA or PDGF receptor signaling inhibitor. Conclusions: The exposure of HCAECs to shear stress of 5 dyn/cm2 caused the dysfunction of Cx40/Cx43 heterotypic myoendothelial gap junctions, which may be replaced by homotypic Cx43/Cx43 channels, and induced HCASMC transition to the synthetic phenotype associated with the activation of PDGF receptor signaling, which may contribute to shear stress-associated arteriosclerosis.

Role of G proteins in shear stress-mediated nitric oxide production by endothelial cells

1994 ◽  
Vol 267 (3) ◽  
pp. C753-C758 ◽  
Author(s):  
M. J. Kuchan ◽  
H. Jo ◽  
J. A. Frangos
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Shear Stress ◽  
G Protein ◽  
G Proteins ◽  
No Production ◽  
Dependent Manner ◽  
Protein Activation ◽  
Synthase Inhibitor

Exposure of cultured endothelial cells to shear stress resulting from well-defined fluid flow stimulates the production of nitric oxide (NO). We have established that an initial burst in production is followed by sustained steady-state NO production. The signal transduction events leading to this stimulation are not well understood. In the present study, we examined the role of regulatory guanine nucleotide binding proteins (G proteins) in shear stress-mediated NO production. In endothelial cells not exposed to shear stress, AIF4-, a general activator of G proteins, markedly elevated the production of guanosine 3',5'-cyclic monophosphate (cGMP). Pretreatment with NO synthase inhibitor N omega-nitro-L-arginine completely blocked this stimulation. Incubation with guanosine 5'-O-(2-thiodiphosphate) (GDP beta S), a general G protein inhibitor, blocked the flow-mediated burst in cGMP production in a dose-dependent manner. Likewise, GDP beta S inhibited NOx (NO2 + NO3) production for the 1st h. However, inhibition was not detectable between 1 and 3 h. Pertussis toxin (PTx) had no effect on the shear response at any time point. The burst in NO production caused by a change in shear stress appears to be dependent on a PTx-refractory G protein. Sustained shear-mediated production is independent of G protein activation.

Recruitment of endothelial caveolae into mechanotransduction pathways by flow conditioning in vitro

2003 ◽  
Vol 285 (4) ◽  
pp. H1720-H1729 ◽  
Author(s):  
Victor Rizzo ◽  
Christine Morton ◽  
Natacha DePaola ◽  
Jan E. Schnitzer ◽  
Peter F. Davies
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Cell Surface ◽  
Tyrosine Phosphorylation ◽  
Surface Proteins ◽  
Luminal Surface ◽  
Laminar Shear Stress ◽  
Caveolin 1 ◽  
Cultured Endothelial Cells ◽  
Laminar Shear

The luminal surface of rat lung microvascular endothelial cells in situ is sensitive to changing hemodynamic parameters. Acute mechanosignaling events initiated in response to flow changes in perfused lung microvessels are localized within specialized invaginated microdomains called caveolae. Here we report that chronic exposure to shear stress alters caveolin expression and distribution, increases caveolae density, and leads to enhanced mechanosensitivity to subsequent changes in hemodynamic forces within cultured endothelial cells. Flow-preconditioned cells expressed a fivefold increase in caveolin (and other caveolar-residing proteins) at the luminal surface compared with no-flow controls. The density of morphologically identifiable caveolae was enhanced sixfold at the luminal cell surface of flow-conditioned cells. Laminar shear stress applied to static endothelial cultures (flow step of 5 dyn/cm2), enhanced the tyrosine phosphorylation of luminal surface proteins by 1.7-fold, including caveolin-1 by 1.3-fold, increased Ser1179 phosphorylation of endothelial nitric oxide synthase (eNOS) by 2.6-fold, and induced a 1.4-fold activation of mitogen-activated protein kinases (ERK1/2) over no-flow controls. The same shear step applied to endothelial cells preconditioned under 10 dyn/cm2 of laminar shear stress for 6 h and induced a sevenfold increase of total phosphotyrosine signal at the luminal endothelial cell surface enhanced caveolin-1 tyrosine phosphorylation 5.8-fold and eNOS phosphorylation by 3.3-fold over static control values. In addition, phosphorylated caveolin-1 and eNOS proteins were preferentially localized to caveolar microdomains. In contrast, ERK1/2 activation was not detected in conditioned cells after acute shear challenge. These data suggest that cultured endothelial cells respond to a sustained flow environment by directing caveolae to the cell surface where they serve to mediate, at least in part, mechanotransduction responses.

scholarly journals Palmitoylation-dependent Estrogen Receptor α Membrane Localization: Regulation by 17β-Estradiol

2005 ◽  
Vol 16 (1) ◽  
pp. 231-237 ◽  
Author(s):  
Filippo Acconcia ◽  
Paolo Ascenzi ◽  
Alessio Bocedi ◽  
Enzo Spisni ◽  
Vittorio Tomasi ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Estrogen Receptor ◽  
Plasma Membrane ◽  
Estrogen Receptor Α ◽  
Membrane Localization ◽  
Target Cells ◽  
Dependent Manner ◽  
Caveolin 1 ◽  
17Β Estradiol

A fraction of the nuclear estrogen receptor α (ERα) is localized to the plasma membrane region of 17β-estradiol (E2) target cells. We previously reported that ERα is a palmitoylated protein. To gain insight into the molecular mechanism of ERα residence at the plasma membrane, we tested both the role of palmitoylation and the impact of E2 stimulation on ERα membrane localization. The cancer cell lines expressing transfected or endogenous human ERα (HeLa and HepG2, respectively) or the ERα nonpalmitoylable Cys447Ala mutant transfected in HeLa cells were used as experimental models. We found that palmitoylation of ERα enacts ERα association with the plasma membrane, interaction with the membrane protein caveolin-1, and nongenomic activities, including activation of signaling pathways and cell proliferation (i.e., ERK and AKT activation, cyclin D1 promoter activity, DNA synthesis). Moreover, E2 reduces both ERα palmitoylation and its interaction with caveolin-1, in a time- and dose-dependent manner. These data point to the physiological role of ERα palmitoylation in the receptor localization to the cell membrane and in the regulation of the E2-induced cell proliferation.

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