Autocrine production of biologically active hepatocyte growth factor (HGF) by injured human skin

SummaryBackgroundHepatocyte growth factor (HGF) is a potent regenerative factor involved in wound healing. Previous studies have shown that mesenchymal cells produce HGF, stimulating epithelial cells in a paracrine fashion.ObjectiveTo examine whether autocrine HGF production by keratinocytes can occur upon skin injury.MethodsA 31-year-old male patient sustained a burn affecting 80% of his total body surface area. Biopsies were taken from intact skin near the injured area, and skin keratinocytes were separated and cultured. Conditioned medium from keratinocytes was analyzed for HGF by ELISA, surface plasmon resonance (SPR), and dot blotting. Binding of HGF from conditioned medium to its receptor, c-Met, was compared with recombinant HGF by SPR. Finally, we examined the motogenic effect on mouse transformed skin epithelial cells (CCL-53.1) of HGF from conditioned medium.ResultsHGF was detected in the cultured keratinocyte medium. Similar to recombinant HGF, HGF from conditioned medium had a high affinity for dextran sulfate and albumin, and the same epitopes were engaged by the interaction of HGF with the c-Met receptor. The conditioned medium from keratinocytes obtained from the burn patient, but not medium from keratinocytes obtained from healthy volunteers, accelerated the motogenesis of CCL-53.1 cells. Unexpectedly, anti-HGF antibodies did not prevent this effect. However, anti-c-Met antibodies completely inhibited the motogenic effect.ConclusionUpon injury, human skin keratinocytes might produce biologically active HGF in an autocrine fashion. This HGF might have different structural and/or biological properties from HGF produced by mesenchymal cells.