(A) Different niches within the pilosebaceous unit house various progenitors that all display plasticity and contribute to wound-induced re-epithelialization, albeit at varying degrees. Ablation of these populations likewise trigger neighbor progenitors to refill the vacated niche.
(B) In contrast, the sweat gland displays stricter compartmentalization in terms of injury response. Wounding of the sweat gland orifice only triggers duct (but not gland) progenitors to reconstruct the sweat duct. Similarly, ablation of specific gland progenitors only activates the same type of progenitor for repair.
SC, stem cell; JZ, junctional zone; SG, sebaceous gland.