Development of PDGF-BB-derived biomaterial: An 'artificial' concatemeric protein for regenerative applications

Wound healing complications affect millions of people each year. New methods are constantly being pursued since the existing ones are not entirely effective. Our previous research on platelet-derived growth factor (PDGF-BB)-derived peptides demonstrated that one of them, PDGF2, possesses promising pro-regenerative potential. Nevertheless, proteases are capable of rapidly degrading peptides. Construction of concatemeric proteins is one approach to enhancing their stability and facilitating their gradual release. We have developed and genetically engineered a concatemeric protein, PDGF2_10, that contains 10 repeats of the PDGF2 amino acid sequence. To enable the bioactive motif to be released gradually, the human neutrophil elastase-specific AAPV sequence was sandwiched between PDGF2 repeats. In vitro, the activity of PDGF2_10 was assessed using various human cells. Proliferation and chemotaxis were analyzed using XTT and transwell assays, respectively. The LDH cytotoxicity method and flow cytometric analysis of immune cell activation were employed to verify biosafety. Wound healing potential and adverse effects were assessed using the dorsal skin injury model in mice. PDGF2_10 exhibits good stability in human serum, and the bioactive motif is released upon incubation with human neutrophil elastase. PDGF2_10 stimulates collagen synthesis in fibroblasts, increases chemotaxis, and exhibits pro-proliferative activity toward human skin cells. Furthermore, it is distinguished by its exceptional safety, as evidenced by its lack of immunogenicity, toxicity, or any other adverse effects following topical administration to dorsal skin wounds in mice. Our findings indicate that, PDGF2 is a promising candidate for regenerative applications, including cell pre-conditioning for cell therapies or skin applications.