Platelet-activating factor enhances the expression of vascular endothelial growth factor in normal human astrocytes under hypoxia

摘要

Platelet-activating factor (PAF) has neuroregulatory activities and is implicated in ischemic injury of the brain. We found that PAF stimulates the expression of vascular endothelial growth factor (VEGF), a potent and specific mitogen for vascular endothelial cells, in normal human astrocytes. Reverse transcription-PCR (RT-PCR) demonstrated the enhancement, by PAF, of the VEGF mRNA expression in time- and concentration-dependent manners. The levels of VEGF protein in astrocyte-conditioned medium were determined by enzyme-linked immunosorbent assay, and 24-h stimulation with 10 nM PAF resulted in 1,3-fold increase in VEGF protein production, When the cells were subjected to hypoxia, the PAF-induced production of VEGF was enhanced by 6,7-fold as compared to the cells stimulated in a similar manner under normoxia. PAF stimulates VEGF expression in human astrocytes, and hypoxia exerts a synergistic effect on the PAF-induced VEGF expression. PAF is known as a mediator of ischemic injury of the nervous tissues, andVEGF may be involved in part of the effect of PAF in brain hypoxia. ?2,003 Elsevier Science B.V All rights reserved.