Effect Of MAPK On Low Shear Stress-induced Expression Of Fkn In Endothelial Cells

Objective: the interaction between blood flow shear stress and the vascular endothelium is an important indicator of cardiovascular function, This study attempts to explore the regulation effect of p38 and JNK MAPK(mitogen-activated protein kinase)signaling pathway in the low shear stress-induced FKN m RNA expression in EA. HY926 cell line.Methods:1)M199 growth medium(containing 1% penicillin streptomycin combination and 10% fetal bovine serum) was used to culture the EA. HY926 cell line. Cell morphology was observed by optical microscope and transmission electron microscopy.Confirmed the EA. HY926 cells have the characteristic of endothelium by immunohistochemistry staining of factor â…§ related antigen and cell growth curve was drawn. 2)Cell morphology alternation in EA. HY926 cells after 60 min exposure of low shear stress was observed by optical microscope. 3)Western blot was employed to detect the phosphorylation of JNK and p38 subfamilies of MAPK. p38 and JNK inhibitors were used to block the MAPK signaling pathway. 4) Real-time PCR was employed to test the expression of FKN m RNA of EA. HY926 cell line.Results: 1)Morphological obsevation by optical microscope showed that the culture dishes were paved with simple EA. HY926 cells after 2 ~ 3d incubation, the cells presented with a spindle/spiral-shaped morphology, tube-like structure can be observed after subculture. Obsevation by transmission electron microscope found the transverse and longitudinal cutting Webel- Palade body;Immunohistochemical results show that the cell cytoplasm was stained with tan; EA. HY926 cell growth curve was stable, suitable for the cell experiment.2)After 60 min low shear stress treatment, the cell morphology is irregular.Increased intercellular cell space, shrunken and detached cells can be observed in local area.3)p38 phosphorylation was upregulated from the 5min exposure of low shear stress(4.58dyne/cm2) and got to the maximum level at 30 min, the expression was decreased after 30 min and achieved lower level than basal level. The phosphorylated p38 can translocated into nuclear and regulated gene expression by corresponding signal transduction pathway. p38 activation and the FKN m RNA expression by low shear stress was inhibited by SB203580. 4) Low shear stress(4.58dyne/cm2) treatment can trigger the upregulation of JNK phosphorylation and the phosphorylation level was increased according to the disposing time. The maximum JNK phosphorylation was occurred at60 min. Phosphorylated JNK translocated into nuclear and control the expression of relevant gene. SP600125 inhibited the activation of JNK and the FKN m RNA expression induced by low shear stress.Conclusion: p38 and JNK MAPK signaling pathways can be activated by low shear stress.The activated p38 and JNK pathways participate in low shear stress-induced FKN expression. Inhibitors of p38 and JNK pathways downregulate the expression of FKN under low shear stress.