Low shear stress induces inflammatory response via CX3CR1/NF-κB signal pathway in human umbilical vein endothelial cells.

Low shear stress (LSS) has been reported to induce atherosclerosis. However, the molecular mechanisms underlying inflammation induced by LSS are still poorly understood. The objective of our study is the comprehensive identification of molecular circuitry involved in low shear stress-induced inflammation in human umbilical vein endothelial cells (HUVECs) through protein profiling and cell function experiment. In this study, Western blotting analyses revealed a significant increase in the expression of CX3CR1, nucleusP65, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and Interleukin-6 (IL-6), while the expression of cytosolic P65 and IκB has significantly decreased in HUVECs treated with low shear stress. CX3CR1 Sh-RNA was use to reveal its effect on LSS-induced inflammation. Further, specific NF-κB P65 inhibitors pyrrolidinedithiocarbamate (PDTC) were used to reveal the downstream NF-κB P65 exclusively involved in LSS-induced inflammation in HUVECs, this effect can be abrogated by CX3CR1 sh-RNA and NF-κB inhibitors. Monocyte adhesion assay and scratch test revealed low shear stress to promotes adhesion of monocytes and migration of cells, this effect can be abrogated by CX3CR1 sh-RNA and NF-κB inhibitors. LSS was involved in the expression of adhesion molecules and chemokines, which are important for the initiation of endothelial inflammation-related atherosclerosis. Therefore, the cell signaling pathways activated by LSS in endothelial cells may represent therapeutic targets of atherosclerosis.

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

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.