scholarly journals Shear Stress Activates p60src-Ras-MAPK Signaling Pathways in Vascular Endothelial Cells

1998 ◽  
Vol 18 (2) ◽  
pp. 227-234 ◽  
Author(s):  
Shila Jalali ◽  
Yi-Shuan Li ◽  
Mohammad Sotoudeh ◽  
Suli Yuan ◽  
Song Li ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Signaling Pathways ◽  
Vascular Endothelial Cells ◽  
Mapk Signaling ◽  
Vascular Endothelial ◽  
Mapk Signaling Pathways

107 FVIIa Prevents the Progressive Hemorrhaging of a Brain Contusion by Protecting Microvessels Via Formation of the TF-FVIIa-FXa Complex

Neurosurgery ◽  
2017 ◽  
Vol 64 (CN_suppl_1) ◽  
pp. 221-222
Author(s):  
Qiang Yuan
Keyword(s):  
Endothelial Cells ◽  
Signaling Pathways ◽  
Signaling Pathway ◽  
Vascular Endothelial Cells ◽  
Mapk Signaling ◽  
Coagulation Cascade ◽  
Cell Protein ◽  
Vascular Endothelial ◽  
Brain Contusion ◽  
Microvessel Endothelial Cells

Abstract INTRODUCTION Factor VII (FVII) plays a key role in the initiation of the coagulation cascade and, in clinical situations, recombinant human activated FVII (rFVIIa) effectively prevents progressive hemorrhaging after a brain contusion. However, it remains unclear whether decreases in FVII activity directly lead to progressive hemorrhaging and, moreover, the precise mechanisms underlying this process are not yet known. METHODS Controlled cortical impact model of mouse brain contusion was used to examine whether decreased FVII activity would directly lead to the occurrence of progressive hemorrhaging in mice and whether administration of FVIIa would prevent the delayed catastrophic structural failure of microvessels and the progressive hemorrhaging of brain contusions by protecting vascular endothelial cells via formation of the ternary TF FVIIa FXa complex. Activations of p44/42 MAPK, p38 MAPK, and p65 NF-kB signaling pathways by ternary TF FVIIa FXa complex were tested by WB in HUVECs. RESULTS >The present study demonstrated that decreased FVII activity directly led to progressive hemorrhaging of the cerebral contusions. Administration of FVII prevented the progression of hemorrhaging from cerebral contusions by protecting microvessel endothelial cells in the penumbra of the contusion. The present study also showed that the ternary TF FVIIa FXa complex cleaved endogenous protease-activated receptor 2 (PAR2) on endothelial cells, activated the p44/42 mitogen-activated protein kinase (MAPK) signaling cascade, and inhibited p65 nuclear factor-kB (NF-kB) signaling. Furthermore, exposure to ternary TF FVIIa FXa protected endothelial cells from thrombin- or inflammatory cytokine-induced apoptosis. Although activation of the p44/42 MAPK signaling pathway is endothelial cell protein C receptor (EPCR)-dependent, inhibition of the p65 NF-kB signaling pathway is EPCR independent; thus, the regulation mechanism underlying the effects of TF FVIIa FXa in vascular endothelial cells appears to be multiple signaling pathways. CONCLUSION In summary, the present findings demonstrated that FVIIa prevented the progressive hemorrhaging of brain contusions by protecting microvessel endothelial cells via the formation of the ternary TF FVIIa FXa complex. These findings are novel and of great clinical significance because FVIIa is used to prevent the progressive hemorrhaging of brain contusions in humans.

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 Low Shear Stress Upregulates CX3CR1 Expression by Inducing VCAM-1 via the NF-κB Pathway in Vascular Endothelial Cells

2020 ◽  
Vol 78 (3) ◽  
pp. 383-389 ◽  
Author(s):  
Yiwei Zhao ◽  
Peile Ren ◽  
Qiufang Li ◽  
Shafiu Adam Umar ◽  
Tan Yang ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Protein Expression ◽  
Vascular Endothelial Cells ◽  
Critical Role ◽  
Mrna Levels ◽  
Vascular Endothelial ◽  
Low Shear Stress ◽  
Low Shear ◽  
Cx3cr1 Expression

Abstract Atherosclerosis is a significant cause of mortality and morbidity. Studies suggest that the chemokine receptor CX3CR1 plays a critical role in atherogenesis. Shear stress is an important mechanical force that affects blood vessel function. In this study, we investigated the effect of shear stress on CX3CR1 expression in vascular endothelial cells (VECs). First, cells were exposed to different shear stress and then CX3CR1 mRNA and protein were measured by quantitative RT-PCR and western blot analysis, respectively. CX3CR1 gene silencing was used to analyze the molecular mechanisms underlying shear stress-mediated effects on CX3CR1 expression. CX3CR1 mRNA and protein expression were significantly increased with 4.14 dyne/cm2 of shear stress compared with other tested levels of shear stress. We observed a significant increase in CX3CR1 mRNA levels at 2 h and CX3CR1 protein expression at 4 h. CX3CR1-induced VCAM-1 expression in response to low shear stress by activating NF-κB signaling pathway in VECs. Our findings demonstrate that low shear stress increases CX3CR1 expression, which increases VCAM-1 expression due to elevated NF-κB activation. The current study provides evidence of the correlation between shear stress and atherosclerosis mediated by CX3CR1.

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