[CXCL1 induces the contraction of endothelial cytoskeleton and increases permeability in mouse cerebral endothelium bEND.3 cells by promoting protein kinase B phosphorylation].

Abstract

Objective To investigate the effects of C-X-C motif chemokine ligand 1 (CXCL1) and its receptor CXCR2 on the cerebral endothelial cytoskeleton rearrangement and permeability in the inflammation of septic encephalopathy. Methods The murine model of septic encephalopathy was established by intraperitoneal injection of LPS (10 mg/kg). The levels of TNF-α and CXCL1 in the whole brain tissue were detected by ELISA. The expression of CXCR2 was detected by Western blot analysis after bEND.3 cells were stimulated with 500 ng/mL LPS and 200 ng/mL TNF-α. After treated with CXCL1(150 ng/mL), the changes of endothelial filamentous actin (F-actin) rearrangement in bEND.3 cells were observed by immuno-fluorescence staining. In the cerebral endothelial permeability test, bEND.3 cells were randomly divided into PBS control group, CXCL1 group, and CXCL1 combined with CXCR2 antagonist SB225002 group. Then endothelial transwell permeability assay kit was used to detect the endothelial permeability changes. After stimulated with CXCL1 in bEND.3 cells, Western blot analysis was used to detect the expression of protein kinase B (AKT) and phosphorylated-AKT (p-AKT). Results Intraperitoneal injection of LPS significantly increased the levels of TNF-α and CXCL1 in the whole brain. LPS and TNF-α both upregulated the expression of CXCR2 protein in bEND.3 cells. CXCL1 stimulation induced the endothelial cytoskeleton contraction, increased paracellular gap formation and elevated endothelial permeability in bEND.3 cells, which was inhibited by the pretreatment with SB225002(CXCR2 antagonist). Furthermore, CXCL1 stimulation also enhanced the phosphorylation of AKT in bEND.3 cells. Conclusion CXCL1 induces the cytoskeleton contraction and increased permeability through AKT phosphorylation in bEND.3 cells, which can be effectively inhibited by CXCR2 antagonist SB225002.