Aged-associated changes in active YAP staining during impaired skin wound healing in aged mice and delayed wound closure in ICE mice
Aging is associated with impaired skin wound healing, but the molecular mechanisms underlying this decline remain incompletely understood. In particular, how aging affects the temporal regulation of mechanosensitive signaling during tissue repair is poorly understood. In this study, we investigated age-associated changes in cutaneous wound healing, with a focus on Yes-associated protein (YAP)-associated mechanosensitive responses, and examined whether ICE mice, an inducible model of epigenetic aging, reproduce age-associated impairment in wound repair. Splinted full-thickness excisional wounds were generated in young and naturally aged mice, and wound closure, gene expression, and active YAP were evaluated over time. Aged mice exhibited delayed wound closure, particularly during the mid-to-late phases of repair. Expression of the fibrosis-related genes Tgfb1, Col1a1, and Col3a1, and the YAP-associated genes Ctgf, Cyr61, and Arhgap18 did not differ significantly between young and aged wounds at the examined time points. In contrast, Ankrd1 was selectively elevated in aged wounds at postoperative day 14. Active YAP immunofluorescence showed age-associated differences in staining patterns during wound healing, indicating altered regulation of mechanosensitive signaling with aging. Furthermore, ICE mice exhibited delayed wound closure compared with Cre control mice, reproducing a major functional feature observed in naturally aged mice. These findings suggest that age-associated impairment of wound healing is characterized not by uniform activation or suppression of YAP-related signaling, but by altered temporal regulation of mechanosensitive responses together with selective Ankrd1 elevation. ICE mice could provide a useful experimental model for investigating age-associated defects in cutaneous wound healing.