To determine whether Wnt signaling may induce epithelial patterning in wound epithelium as occurs during development, LiCl was applied continuously to the wounds of mice. (a) The adjacent normal skin of a 30 day LiCl treated mouse wound shows normal epithelial appendages and dermal architecture. (b) The same animal, but the wound has been treated with LiCl for 14 days and which shows the presence of epithelial inclusion cysts throughout the wound (arrow; day 30). Note the difference in the dermal architecture between the wounded tissue and normal skin; LiCl treatment had no observable effect on the dermal wound healing response. (c) Occasional larger and more mature appearing epithelial appendages can be seen within the wound (different animal; same time point), demonstrating the formation of sebaceous glands (arrow). Retroviral infected wounds were examined after 21 days and shows CD5 expression in 17% of the wound cells by flow cytometry (d) and (e) shows the histologic effect on the control retroviral treated wound at day 30: lacking any epithelial appendages overlying the wound. (f) Immunofluorescent detection of CD5 shows the infection has occurred in the dermal cells (red staining) adjacent to the normal skin, hair follicles in normal skin can be seen on the left and the wound is to the right of the arrow. By day 30 and persisting through day 90, numerous large epithelia-lined cysts can be seen in the wound (g & h) immediately adjacent to the mature normal skin hair follicles (normal skin is left of the line; wound to the right). (i) These cysts were also associated with sebaceous gland formation. (j) Wounds from PMXWnt-5a treated mice were examined for β-catenin stabilization and compared with control retroviral treated wounds. No significant difference in the amount of free β-catenin was seen between the two groups.
Fathke et al. BMC Cell Biology 2006 7:4 doi:10.1186/1471-2121-7-4