Distinct roles for Dectin-1 and Dectin-2 in skin wound healing and neutrophilic inflammatory responses.

Abstract C-type lectin receptors (CLRs) recognize microbial polysaccharides. The CLRs Dectin-1 and Dectin-2, which are triggered by β-glucan and α-mannan, respectively, contribute to up-regulation of the inflammatory response. Recently, we demonstrated that activation of the Dectin-2 signal delayed wound healing; in previous studies, triggering the Dectin-1 signal promoted this response. However, the precise roles of these CLRs in skin wound healing remain unclear. This study was conducted to determine the roles of Dectin-1 and Dectin-2 in skin wound healing, with a particular focus on the kinetics of neutrophilic inflammatory response. Full-thickness wounds were created on the backs of C57BL/6 mice, and the effects of Dectin-1 or Dectin-2 deficiency and those of β-glucan or α-mannan administration were examined. We also analyzed wound closure, histological findings, and neutrophilic inflammatory response including neutrophil extracellular trap (NET) formation at the wound sites. We found that Dectin-1 contributed to the acceleration of wound healing by inducing early-phase neutrophil accumulation, whereas Dectin-2 was involved in prolonged neutrophilic responses and NET formation, leading to delayed wound healing. Dectin-2 deficiency also improved collagen deposition and TGF-β1 expression. These results suggest that Dectin-1 and Dectin-2 have different roles in wound healing through their different effects on the neutrophilic response.