Activated human neutrophils release hepatocyte growth factor/scatter factor

Background: Hepatocyte growth factor or scatter factor (HGF/SF) is a pleiot ropic cytokine that has potent angiogenic properties. We have previously de monstrated that neutrophils (PMN) are directly angiogenic by releasing vasc ular endothelial growth factor (VEGF). We hypothesized that the acute infla mmatory response can stimulate PMN to release HGF. Aims: To examine the effects of inflammatory mediators on PMN HGF release a nd the effect of recombinant human HGF (rhHGF) on PMN adhesion receptor exp ression and PMN VEGF release. Methods: in the first experiment, PMN were isolated from healthy volunteers and stimulated with tumour necrosis factor-alpha (TNF-alpha), lipopolysacc haride (LPS), interleukin-8 (IL-8), and formyl methionyt-leucyl-phenylalani ne (fMLP). Culture supernatants were assayed for HGF using ELISA. In the se cond experiment, PMN were lysed to measure total HGF release and HGF expres sion in the PMN was detected by Western immunoblotting. Finally, PMN were s timulated with rhHGF. PMN CD 11a, CD 11b, and CD 18 receptor expression and VEGF release was measured using flow cytometry and ELISA respectively. Results: TNF-alpha LPS and fMLP stimulation resulted in significantly incre ased release of PMN HGF (755 +/- 216, 484 +/- 221 and 565 +/- 278 pg/ml, re spectively) compared to controls (118 +/- 42 pg/ml). IL-8 had no effect. To tal HGF release following cell lysis and Western blot suggests that HGF is released from intracellular stores. Recombinant human HGF did not alter PMN adhesion receptor expression and had no effect on PMN VEGF release. Conclusions: This study demonstrates that pro-inflammatory mediators can st imulate HGF release from a PMN intracellular store and that activated PMN i n addition to secreting VEGF have further angiogenic potential by releasing HGF. (C) 2001 Harcourt Publishers Ltd.