Construction of chimeric human epidermal growth factor containing short collagen-binding domain moieties for use as a wound tissue healing agent.

Among the various human growth factors, epidermal growth factor (hEGF, consisting of 53 amino acids) has various effects on cell regeneration, stimulation of proliferation, migration of keratinocytes, formation of granulation tissues, and stimulation of fibroblast motility, which are important for wound healing. Owing to their multiple activities, EGFs are used as pharmaceutical and cosmetic agents. However, their low productivity, limited target specificity, and short half-life inhibit their application as therapeutic agents. To overcome these obstacles, we fused the collagen-binding domain (CBD) of Vibrio mimicus metalloprotease to EGF protein. About 18 or 12 amino acids (aa) (of the 33 total amino acids), which were essential for collagen-binding activity, were combined with the N- and C-termini of EGF. We constructed, expressed, and purified EGF (53 aa)-CBD (18 aa), EGF (53 aa)-CBD (12 aa), CBD (18 aa)-EGF (53 aa), and CBD (12 aa)-EGF (53 aa). These purified recombinant proteins increased the numbers of cells in treated specimens compared with non-treated specimens and control hEGF samples. The collagen-binding activities were also evaluated. Furthermore, CBD-hybridized hEGF induced phosphorylation of the EGF receptor. These results suggested that these fusion proteins could be applicable as small therapeutic agents in wound tissue healing.