Ras Induction of Superoxide Activates ERK-dependent Angiogenic Transcription Factor HIF-1α and VEGF-A Expression in Shock Wave-stimulated Osteoblasts

Feng Sheng Wang, Ching Jen Wang, Yeung Jen Chen, Per Rong Chang, Yu Ting Huang, Yi Chih Sun, Hueng Chen Huang, Ya Ju Yang, Kuender D. Yang*

*此作品的通信作者

研究成果: 期刊稿件文章同行評審

204 引文 斯高帕斯(Scopus)

摘要

Vascular endothelial growth factor (VEGF) released by osteoblasts plays an important role in angiogenesis and endochondral ossification during bone formation. In animal studies, we have reported that shock waves (SW) can promote osteogenic differentiation of mesenchymal stem cells through superoxide-mediated signal transduction (Wang, F. S., Wang, C. J., Sheen-Chen, S. M., Kuo, Y. R., Chen, R. F., and Yang, K. D. (2002) J. BioL Chem. 277, 10931-10937) and vascularization of the bone-tendon junction. Here, we found that SW elevation of VEGF-A expression in human osteoblasts to be mediated by Ras-induced superoxide and ERK-dependent HIF-1α activation. SW treatment (0.16 mJ/mm2, 1 Hz, 500 impulses) rapidly activated Ras protein (15 min) and Rac1 protein (30 min) and increased superoxide production in 30 min and VEGF mRNA expression in 6 h. Early scavenging of superoxide, but not nitric oxide, peroxide hydrogen, or prostaglandin E2, reduced SW-augmented VEGF-A levels. Inhibition of superoxide production by diphenyliodonium, an NADPH oxidase inhibitor, was found to suppress VEGF-A expression. Transfection of osteoblasts with a dominant negative (S17N) Ras mutant abrogated the SW enhancement of Rac1 activation, superoxide synthesis, and VEGF expression. Further studies demonstrated that SW significantly promoted ERK activation in 1 h and HIF-1α phosphorylation and HIF-1α binding to VEGF promoter in 3 h. In support of the observation that superoxide mediated the SW-induced ERK activation and HIF-1α transactivation, we further demonstrated that scavenging of superoxide by superoxide dismutase and inhibition of ERK activity by PD98059 decreased HIF-1α activation and VEGF-A levels. Moreover, culture medium harvested from SW-treated osteoblasts increased vessel number of chick chorioallantoic membrane. Superoxide dismutase pretreatment and anti-VEGF-A antibody neutralization reduced the promoting effect of conditioned medium on angiogenesis. Thus, modulation of redox reaction by SW may have some positive effect on angiogenesis during bone regeneration.

原文英語
頁(從 - 到)10331-10337
頁數7
期刊Journal of Biological Chemistry
279
發行號11
DOIs
出版狀態已出版 - 12 03 2004
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