Role of TRPV6-Mediated Calcium Signaling in High-Glucose-Inhibited Keratinocyte Migration

Impaired wound healing, as one of the characteristics of chronic diabetic wounds, is associated with decreased keratinocyte migration. Calcium (Ca²⁺), a vital intracellular second messenger, also plays an important role in wound healing. Here, we found that the expression of the highly selective epithelial Ca²⁺ channel TRPV6 was decreased in diabetic mice skin tissue, and TRPV6 expression and the influx of Ca²⁺ were reduced in keratinocytes cultured in a high-glucose medium. TRPV6 knockdown reduced keratinocyte migration, whereas TRPV6 overexpression increased it. RNA sequencing identified FN1, a protein related to wound healing and cell migration, as a key differentially expressed gene after TRPV6 knockdown in keratinocytes. A high-glucose environment inhibited FN1 expression, and cell migration was inhibited by FN1 knockdown in keratinocytes. While TRPV6 knockdown reduced FN1 expression, TRPV6 overexpression increased it. In addition, knockdown of FN1 in TRPV6 overexpressed keratinocytes reduced cell migration. The calmodulin inhibitor W-7 or TFP suppressed the TRPV6 overexpression-induced increases in FN1 expression and cell migration, whereas the Akt inhibitor LY294002 or MK2206 restored the TRPV6 overexpression-induced increases in FN1 expression and cell migration to control levels in keratinocytes. Taken together, these results indicated that high glucose inhibits the expression of TRPV6 in keratinocytes, decreases Ca²⁺ flow into these cells, and decreases FN1 expression via Ca²⁺-calmodulin and Akt signaling to inhibit keratinocyte migration. Thus, TRPV6 may be a potential target for the development of novel treatments in diabetes-induced impaired wound healing.