Hair-follicle-associated pluripotent (HAP) stem cells reside in the upper part of the bulge area of the the hair follicle. HAP stem cells are nestin-positive and keratin 15-negative and have the capacity to differentiate into various types of cells in vitro. HAP stem cells are also involved in nerve and spinal cord regeneration in mouse models. Recently, it was shown that the DNA-damage response in non-HAP hair follicle stem cells induces proteolysis of type-XVII collagen (COL17A1/BP180), which is involved in hair-follicle stem-cell maintenance. COL17A1 proteolysis stimulated hair-follicle stem-cell aging, characterized by the loss of stemness signatures and hair-follicle miniaturization associated with androgenic alopecia. In the present study, we demonstrate that HAP stem cells co-express nestin and COL17A1 in vitro and in vivo. The expression of HAP stem cell markers (nestin and SSEA1) increased after HAP stem-cell colonies were formed, then decreased after differentiation to epidermal keratinocytes. In contrast COL17A1 increased after differentiation to epidermal keratinocytes. These results suggest that COL17A1 is important in differentiation of HAP stem cells.

中文翻译：

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分化过程中毛囊相关多能 (HAP) 干细胞中抗衰老 XVII 型胶原 (COL17A1/BP180) 的表达。


毛囊相关多能（HAP）干细胞位于毛囊凸起区域的上部。 HAP干细胞呈巢蛋白阳性、角蛋白15阴性，具有在体外分化成各种类型细胞的能力。 HAP 干细胞还参与小鼠模型中的神经和脊髓再生。最近，研究表明，非 HAP 毛囊干细胞中的 DNA 损伤反应会诱导 XVII 型胶原蛋白 (COL17A1/BP180) 的蛋白水解，从而参与毛囊干细胞的维持。 COL17A1 蛋白水解刺激毛囊干细胞衰老，其特征是干性特征丧失和与雄激素性脱发相关的毛囊小型化。在本研究中，我们证明 HAP 干细胞在体外和体内共表达巢蛋白和 COL17A1。 HAP干细胞标志物（nestin和SSEA1）的表达在HAP干细胞集落形成后增加，然后在分化为表皮角质形成细胞后减少。相反，COL17A1 在分化为表皮角质形成细胞后增加。这些结果表明COL17A1在HAP干细胞的分化中很重要。