Effect of EphB4/EphrinB2 reverse signal on angiogenesis induced by Xuefu Zhuyu Capsule () containing serum in human microvascular endothelial cell 1.

OBJECTIVE

To evaluate the effect of Xuefu Zhuyu Capsule ()-containing serum (XFZY-CS) on EphB4/ephrinB2 and its reverse signal in human microvascular endothelial cell-1 (HMEC-1).

METHODS

XFZY-CS and the blank control serum were collected. HMEC-1 cells were randomly assigned to 6 groups including the concentration 1.25%, 2.5%, and 5% XFZY-CS groups and their blank serum control ones. The angiogenesis effect of XFZY-CS was tested with an in vitro tube formation assay and the best condition of pro-angiogenesis was determined. The effect of XFZY-CS on EphB4/ephrinB2 and the reverse signal were determined by Western blot and real-time quantitative polymerase chain reaction, respectively; we also confifirmed the results through activating and inhibiting the reverse signal by EphB4/fc and pyrophosphatase/ phosphodiesterase2 (PP2).

RESULTS

XFZY-CS promoted angiogenesis at the concentration of 2.5% corresponding serum after being cultured for 48 h, while inhibited angiogenesis at the concentration of 5% after culturing for 48 and 72 h. Under the 2.5% serum concentration, XFZY up-regulated the expression of EphB4-mRNA at 12 h (P<0.05), and down-regulates its expression at 24 h (P<0.01). Protein expression of EphB4 was apparently up-regulated at 12 h and down-regulated at 24 h. The phosphorylation of ephrinB2 increased at 9 h (P<0.05). In addition, 2.5% XFZY-CS played a similar role as the reverse signaling activator EphB4/Fc ranging from 0.5 to 5 μg/mL (P>0.05). XFZY-CS also reduced the inhibitive effect of PP2 in limited periods.

CONCLUSIONS

EphB4/ephrinB2 was the upstream signal in the process of angiogenesis and its reverse signaling was responsible for XFZY's effect on promoting angiogenesis.