Poly I:C induces collective migration of HaCaT keratinocytes via IL-8.

ABSTRACT

BACKGROUND: Delayed wound healing reduces the quality of life (QOL) of patients. Thus, understanding the mechanism of wound healing is indispensable for better management. However, the role of innate immunity in wound healing is thus far unknown. Recently the involvement of TLR3 in wound healing has been evaluated. The systemic administration of polyriboinosinic-polyribocytidylic acid (poly IC ; a substitute for viral dsRNA and a ligand of toll-like receptor 3), enhances wound healing in vivo. The aim of this study is to improve our understanding of the link between innate immunity and human wound healing, particularly in re-epithelialization. RESULTS: The present study showed that poly IC significantly accelerated collective HaCaT cell migration in a scratch assay. Poly IC also increased IL-8 and bFGF production, and anti-IL-8 antibodies significantly inhibited the migration caused by poly IC. Human recombinant IL-8 also accelerated collective HaCaT cell migration. An immunofluorescence assay and enzyme-linked immunosorbent assay (ELISA) also revealed that poly IC decreased E-cadherin protein levels and increased vimentin protein levels, and anti-IL-8 antibody reversed this effect. In contrast, nucleic/cytosolic protein ratios of Snail 1 were unchanged in all tested conditions. CONCLUSION: Our findings demonstrated that poly IC accelerated collective HaCaT cell migration via autocrine/paracrine secretions of IL-8 and the subsequent incomplete epithelial-mesenchymal transition (EMT). Our findings provide a new strategy for wound healing by regulating innate immune systems in re-epithelialization.