Fas-mediated upregulation of vascular endothelial growth factor and monocyte chemoattractant protein-1 expression in cultured dermal fibroblasts: role in the inflammatory response.

The Fas-Fas ligand interaction is the most important pathway in starting apoptosis. In addition, several recent reports have emerged documenting non-apoptotic roles for Fas. However, a non-apoptotic role of Fas in dermal fibroblasts remains unknown. The present study investigated whether Fas stimulation not only promotes apoptosis but also stimulates elements of the inflammatory response such as angiogenesis and macrophage infiltration. Fas stimulation was performed by treating cultured human dermal fibroblasts with an agonistic anti-Fas monoclonal antibody (mAb). Anti-Fas mAb-treated fibroblasts showed a significantly greater increase of caspase-3 and caspase-8 activity compared with control fibroblasts. Addition of the anti-Fas mAb induced DNA fragmentation, as confirmed by the DNA ladder assay. Terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling (TUNEL) staining showed that treatment with the anti-Fas mAb induced an increase of apoptotic fibroblasts in a time-dependent manner. At both mRNA and protein levels, anti-Fas mAb-treated fibroblasts showed significantly higher expression of vascular endothelial growth factor (VEGF) and monocyte chemoattractant protein (MCP)-1 compared with control fibroblasts. A pan-caspase inhibitor (Z-VAD-FMK) significantly inhibited VEGF and MCP-1 expression. After transplantation of fibroblasts into mice with severe combined immunodeficiency, the nodules derived from anti-Fas mAb-treated fibroblasts showed more abundant neovascularization, increased macrophage infiltration, and more apoptotic cells in comparison with nodules derived from control fibroblasts. The results of both in vitro and in vivo studies confirmed significantly higher angiogenic activity and macrophage chemotactic activity of anti-Fas mAb-treated fibroblasts compared with control fibroblasts.