The Epithelial Mitogen Keratinocyte Growth Factor Binds to Collagens via the Consensus Sequence Glycine-Proline-Hydroxyproline

Martin Ruehl,Rajan Somasundaram,Ines Schoenfelder,Richard W Farndale,C Graham Knight,Monika Schmid,Renate Ackermann,Ernst Otto Riecken,Martin Zeitz,Detlef Schuppan

doi:10.1074/jbc.m202335200

Abstract

The binding of certain growth factors and cytokines to components of the extracellular matrix can regulate their local availability and modulate their biological activities. We show that mesenchymal cell-derived keratinocyte growth factor (KGF), a key stimulator of epithelial cell proliferation during wound healing, preferentially binds to collagens I, III, and VI. Binding is inhibited in a dose-dependent manner by denatured single collagen chains and collagen cyanogen bromide peptides. This interaction is saturable with dissociation constants of approximately 10(-8) to 10(-9) m and estimated molar ratios of up to three molecules of KGF bound to one molecule of triple helical collagen. Furthermore, collagen-bound KGF stimulated the proliferation of transformed keratinocyte or HaCaT cells. Ligand blotting of collagen-derived peptides points to a limited set of collagenous consensus sequences that bind KGF. By using synthetic collagen peptides, we defined the consensus sequence (Gly-Pro-Hyp)(n) as the collagen binding motif. We conclude that the preferential binding of KGF to the abundant collagens leads to a spatial pattern of bioavailable KGF that is dictated by the local organization of the collagenous extracellular matrix. The defined collagenous consensus peptide or its analogue may be useful in wound healing by increasing KGF bioactivity and thus modulating local epithelial remodeling and regeneration.

Highlights

The binding of certain growth factors and cytokines to components of the extracellular matrix can regulate their local availability and modulate their biological activities
We show that mesenchymal cell-derived keratinocyte growth factor (KGF), a key stimulator of epithelial cell proliferation during wound healing, preferentially binds to collagens I, III, and VI
We demonstrated that KGF binds to immobilized collagens in the order type VI 3 III 3 I 3 II 3 IV in vitro

Summary

Introduction

The binding of certain growth factors and cytokines to components of the extracellular matrix can regulate their local availability and modulate their biological activities. We show that mesenchymal cell-derived keratinocyte growth factor (KGF), a key stimulator of epithelial cell proliferation during wound healing, preferentially binds to collagens I, III, and VI. Components of the extracellular matrix including collagens were shown to interact with several growth factors and cytokines, modulating their local availability and biological activity [1,2,3,4,5]. In vitro and in vivo studies show a beneficial or protective effect of KGF on cutaneous wound healing [10], lung injury [21], experimental colitis [22], cyclophosphamide-induced cystitis [23], and gastric wound healing [13, 16, 24, 25] In line with these findings are clinical trials with FGF-10 for wound healing and treatment of mucositis caused by cancer therapy (26 –29). Heparan sulfate proteoglycans potentiate the biological activity of FGF-1 but strongly inhibit the activity of KGF/FGF-7 [31]

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Conclusion