Mxi1-0 regulates autocrine production of IL-8 in HUVECs via EKR1/2-dependent pathway.

(A) Mxi1-0 expression and MAPK activation during HUVECs proliferation. HUVECs were cultured in the absence of serum for 24 h before stimulation with 20% serum for the indicated amount of time. The lysates were fractionated and analyzed by Western blotting with the indicated antibodies. (B) Effects of Mxi1-0 knockdown on the activation of MAPK pathway. The levels of phosphorylated ERK1/2, p38 and JNK in ssiRNA or siMxi1-0-transfected cells were measured by Western blot. **P<0.01 vs. scrambled siRNA. NS: no statistically difference vs. scrambled siRNA. (C& D) The effect of MEK inhibitor U0126 on Mxi1-0 overexpression-induced IL-8 in HUVECs. Mxi1-0-overexpressed cells were pre-treated with 10 μM U0126 for 2 h. The expression of IL-8 mRNA was estimated by qRT-PCR (C), and the level of secreted IL-8 was measured by ELISA (D), respectively. **P<0.01 vs.Vector, ##P<0.01 vs. Control.