Cooperative Division of Veterinary Sciences, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 183-8509, Japan.
Division of Animal Life Science, Institute of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 183-8509, Japan.
Sci Rep. 2022 Oct 24;12(1):17820. doi: 10.1038/s41598-022-22427-2.
Nestin is an intermediate filament protein transiently expressed in neural stem/progenitor cells. We previously demonstrated that outer root sheath (ORS) keratinocytes of adult hair follicles (HFs) in mice descend from nestin-expressing cells, despite being an epithelial cell lineage. This study determined the exact stage when nestin-expressing ORS stem/precursor cells or their descendants appear during HF morphogenesis, and whether they are present in adult HFs. Using Nes-Cre/CAG-CAT-EGFP mice, in which enhanced green fluorescent protein (EGFP) is expressed following Cre-based recombination driven by the nestin promoter, we found that EGFP cells appeared in the epithelial layer of embryonic HFs as early as the peg stage. EGFP cells in hair pegs were positive for keratin 14 (K14) and K5, but not vimentin, SOX2, SOX10, or S100 alpha 6. Tracing of tamoxifen-induced EGFP cells in postnatal Nes-CreERT2/CAG-CAT-EGFP mice revealed labeling of some isthmus HF epithelial cells in the first anagen stage. EGFP cells in adult HFs were not immunolabeled for K15, an HF multipotent stem cell marker. However, when hairs were depilated in Nes-CreERT2/CAG-CAT-EGFP mice to induce the anagen stage after tamoxifen injection, the majority of ORS keratinocytes in depilation-induced anagen HFs were labeled for EGFP. Our findings indicate that nestin-expressing unipotent progenitor cells capable of differentiating into ORS keratinocytes are present in HF primordia and adult HFs.
巢蛋白是一种中间丝蛋白，在神经干细胞/祖细胞中短暂表达。我们之前的研究表明，尽管毛囊（HF）的外根鞘（ORS）角蛋白细胞属于上皮细胞谱系，但它们来源于巢蛋白表达细胞。本研究旨在确定在 HF 形态发生过程中，表达巢蛋白的 ORS 干细胞/前体细胞或其后代出现的确切阶段，以及它们是否存在于成年 HF 中。使用 Nes-Cre/CAG-CAT-EGFP 小鼠，其中增强型绿色荧光蛋白（EGFP）在巢蛋白启动子驱动的基于 Cre 的重组后表达，我们发现 EGFP 细胞早在钉突阶段就出现在胚胎 HF 的上皮层中。发现在毛钉中的 EGFP 细胞为角蛋白 14（K14）和 K5 阳性，但不为波形蛋白、SOX2、SOX10 或 S100 alpha 6 阳性。对出生后 Nes-CreERT2/CAG-CAT-EGFP 小鼠中诱导的 EGFP 细胞进行示踪，发现一些处于第一生长期的峡部 HF 上皮细胞被标记。在成年 HF 中，EGFP 细胞不被 HF 多能干细胞标志物 K15 免疫标记。然而，当在 Nes-CreERT2/CAG-CAT-EGFP 小鼠中脱毛以在注射他莫昔芬后诱导生长期时，大多数脱毛诱导的生长期 HF 中的 ORS 角蛋白细胞被 EGFP 标记。我们的研究结果表明，在 HF 原基和成年 HF 中存在能够分化为 ORS 角蛋白细胞的表达巢蛋白的单能祖细胞。
