LGI3 promotes human keratinocyte migration in high-glucose environments by increasing the expression of β-catenin.

The leucine-rich repeat LGI family member 3 (LGI3) has been reported to regulate various functions in epidermal keratinocytes. In this study, we investigated the effects of LGI3 on keratinocyte migration in environments with different glucose concentrations. Our results showed that cell migration is markedly impaired in high-glucose environments compared to in low-glucose environments (control). Nevertheless, the use of LGI3 in high-glucose environments restores cell migration to the normal level. Therefore, we performed LGI3 knockdown to identify the role of LGI3 in cell migration. It was observed that transfecting LGI3 siRNA into HaCaT cells reduces the expression of LGI3 and inhibits wound closure. These results indicate that LGI3 is deeply involved in wound healing in high-glucose environments. Western blot analysis showed that in high-glucose environments, LGI3 increases the phosphorylation of Akt, forkhead box protein O1, and focal adhesion kinase. However, no change was observed in the levels of glycogen synthase kinase 3β, c-Jun N-terminal kinase, extracellular signal-regulated kinase, or p38 mitogen-activated protein kinase. Further results showed that LY294002, a specific inhibitor of phosphatidylinositol 3-kinase, reduced LGI3-induced cell migration. It is generally known that Akt activation leads to the accumulation of β-catenin, an important mediator of keratinocyte migration. LGI3 greatly increased the expression of β-catenin in high-glucose environments comparison to that in the low-glucose environments. Taken together, these data indicate that LGI3 induces keratinocyte migration in high-glucose environments as a result of β-catenin accumulation via Akt phosphorylation. Therefore, LGI3 can be considered a new treatment option for diabetic wound healing.