Poly(ethylene glycol) conjugation to glycyl-L-histidyl-L-lysine peptide enhances fibroblast proliferation and wound healing in rats

초록

Glycyl-L-histidyl-L-lysine (GHK) has been shown to promote wound healing by enhancing collagen synthesis in fibroblasts. Although lipidated GHK, such as palmitoyl-GHK, is widely used in cosmetics, there are few studies on the clinical use of GHK conjugated with hydrophilic polymers such as poly(ethylene glycol) (PEG). Therefore, herein, we investigated the effect of PEG conjugation to the N-terminal amine of GHK on cell proliferation and in vitro / in vivo wound healing. N-terminal site-specific PEGylation was performed via a reductive amination reaction using aldehyde-activated PEG under mild acidic conditions. The biological activities of the PEGylated GHKs were assessed using cell proliferation and wound healing assays. Notably, each N-terminally PEGylated GHK (PEG-GHK) promoted cell proliferation and stimulated type I collagen synthesis in Hs68 fibroblast cells. Three PEG-GHK species prepared by using PEG of different molecular weights (2, 5, and 10 kDa); among them, 5 kDa-PEG-conjugated GHK (PEG5K-GHK) showed the highest stimulatory effect on cell proliferation and type I collagen synthesis. The cell migration assay confirmed that PEG5K-GHK treatment significantly accelerated in vitro wound healing relative to treatment with non-PEGylated GHK. In vivo experiments using rats showed that PEG5K-GHK treatment for 10 days significantly increased wound closure percentage compared with GHK treatment. Conclusively, these study findings demonstrate that PEG conjugation may enhance the cell proliferation and wound healing effects of GHK.

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