Faculty of Veterinary Medicine, Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, Alberta, Canada.
Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.
Exp Dermatol. 2019 Apr;28(4):419-424. doi: 10.1111/exd.13924.
The dermal papilla (DP) is one of two principal mesenchymal compartments of the hair follicle (HF). We previously reported that a population of HF dermal stem cells (hfDSCs) function to regenerate the dermal sheath (DS), but intriguingly also contribute new cells to the adult DP at the onset of anagen hair growth to maintain normal cycling of HFs and support the production of large hair fibres. Here, we asked whether injury altered the behaviour of hfDSCs and their progeny in order to support wound-induced hair growth (WIHG) and if the response was modulated by hair cycle stage. αSMACreER :ROSA mice received tamoxifen to label the DS, including hfDSCs. Full-thickness excisions were made on the dorsal skin during various stages of the hair cycle. The skin was harvested at the subsequent anagen. Interestingly, there was an increase in the magnitude of recruitment of hfDSC progeny into the DP after injury compared to follicles entering natural second anagen. This bias towards a DP fate only occurred when a wound was induced during certain stages of the HC. In summary, injury modifies the fate of hfDSCs progeny, biasing them towards recruitment into the DP, with the hair cycle stage also influencing this response.
真皮乳头（DP）是毛囊（HF）的两个主要间质隔室之一。我们之前曾报道过，毛囊真皮干细胞（hfDSC）群体的功能是再生真皮鞘（DS），但令人好奇的是，在生长期开始时，它们还会向成年 DP 贡献新细胞，以维持 HF 的正常循环，并支持大毛发纤维的产生。在这里，我们询问了损伤是否改变了 hfDSC 及其后代的行为，以支持创伤诱导的毛发生长（WIHG），以及这种反应是否受毛发生长周期阶段的调节。αSMACreER：ROSA 小鼠接受他莫昔芬标记 DS，包括 hfDSC。在毛发生长周期的各个阶段对背部皮肤进行全层切除。在随后的生长期收获皮肤。有趣的是，与自然进入第二次生长期的毛囊相比，损伤后 hfDSC 后代进入 DP 的募集幅度增加。只有当 HC 的某些阶段发生创伤时，才会出现这种偏向 DP 命运的趋势。总之，损伤改变了 hfDSC 后代的命运，使它们偏向于募集到 DP 中，而毛发生长周期阶段也会影响这种反应。
