Copper–GHK increases integrin expression and p63 positivity by keratinocytes
Glycyl-l-histidyl-l-lysyl (GHK) possesses a high affinity for copper(II) ions, with which it spontaneously forms a complex (copper–GHK). It is well known that copper–GHK plays a physiological role in the process of wound healing and tissue repair by stimulating collagen synthesis in fibroblasts. This study was conducted to investigate the effects of copper–GHK on keratinocytes. Proliferative effects were analyzed and hematoxylin and eosin staining and immunohistochemistry were conducted to evaluate the effects of copper–GHK in skin equivalent (SE) models. In addition, western blotting was performed. In monolayer cultured keratinocytes, copper–GHK increased the proliferation of keratinocytes. When the SE models were evaluated, basal cells became cuboidal when copper–GHK was added. Immunohistochemical analysis revealed that copper–GHK increased proliferating cell nuclear antigen (PCNA) and p63 positivity. Furthermore, the expression of integrin α6 and β1 increased in SE models, and these results were confirmed by Western blotting. The results of this study indicate that treatment with copper–GHK may increase the proliferative potential of basal keratinocytes by modulating the expression of integrins, p63 and PCNA. In addition, increased levels of p63, a putative stem cell marker of the skin, suggests that copper–GHK promotes the survival of basal stem cells in the skin.