Loxosceles deserta spider venom induces the expression of vascular endothelial growth factor (VEGF) in keratinocytes

Evenomation by arachnids of the genus Loxosceles frequently results in disf iguring necrotic skin lesions. The cellular and molecular mechanisms which contribute to lesion development are incompletely defined but appear to inv olve participation of several pro-inflammatory mediators. We have recently observed that Loxosceles deserta venom induces the production of chemokines in human umbilical vein endothelial cells (HUVECs) and human pulmonary epi thelial cells. In the present study we observed that Loxosceles deserta ven om induces the expression of vascular endothelial growth factor (VEGF) in h uman keratinocytes but little in smooth muscle cells and none in pulmonary epithelial cells. A potent endothelial cell-specific mitogen, VEGF induces angiogenesis and vascular permeability in vivo. RNase protection assay data indicate that VEGF mRNA concentrations in keratinocytes are significantly increased at 2 h following venom exposure. These data suggest that keratino cyte-derived VEGF may contribute to the vasodilation, edema and erythema wh ich occur following Loxosceles evenomation.