Figure 2.

Signaling pathways leading to scarring or regeneration. The outcome of skin wound healing is a balance of signaling pathways leading to scarring or regeneration. Upregulation of Cadherins, ICAM-1, or Connexins or overactivation of Hippo/YAP, integrin/FAK/Rho GTPase, c-JUN/PI3K/AKT, or Wnt/β-catenin signaling in fibroblasts leads to pathological scarring, such as scleroderma, hypertrophic scar, and keloids. Activation of Sonic Hedgehog (Shh) signaling in keratinocytes and wound fibroblasts, or activation of Wnt/β-catenin, SOX2/PITX1, or TLR3/IL-6/STAT3 in keratinocytes (but not in fibroblasts) promotes regeneration, as seen in wound-induced hair follicle regeneration, oral mucosa repair, and fetal scarless healing. (FB), only in fibroblasts; (KC), only in keratinocytes.