Scientists found that short pieces taken from several growth‑factor proteins can kill bacteria and fungi, working like the natural antimicrobial peptide LL‑37 by breaking cell membranes, and they don’t damage red blood cells.

Growth factors, comprising diverse protein and peptide families, are involved in a multitude of developmental processes, including embryogenesis, angiogenesis, and wound healing. Here we show that peptides derived from HB-EGF, amphiregulin, hepatocyte growth factor, PDGF-A and PDGF-B, as well as various FGFs are antimicrobial, demonstrating a previously unknown activity of growth factor-derived peptides. The peptides killed the Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa, and the Gram-positive Bacillus subtilis, as well as the fungus Candida albicans. Several peptides were also active against the Gram-positive S. aureus. Electron microscopy analysis of peptide-treated bacteria, paired with analysis of peptide effects on liposomes, showed that the peptides exerted membrane-breaking effects similar to those seen after treatment with the "classical" human antimicrobial peptide LL-37. Furthermore, HB-EGF was antibacterial per se, and its epitope GKRKKKGKGLGKKRDPCLRKYK retained its activity in presence of physiological salt and plasma. No discernible hemolysis was noted for the growth factor-derived peptides. Besides providing novel templates for design of peptide-based antimicrobials, our findings demonstrate a previously undisclosed link between the family of growth factors and antimicrobial peptides, both of which are induced during tissue remodelling and repair.