Identification of Keratin 5 expression lineage fibroblasts in hair follicles

We investigated epidermis derived fibroblasts in neonatal skin at single cell-transcriptomic levels. We found that keratin 5 lineage mesenchymal cells mainly showed the transcriptomic signatures as dermal papilla and dermal sheath cells. Our data suggested that hair follicle dermal cells were originally derived from epidermis via epithelial to mesenchymal transition. Neonatal skins from head, back and abdomen of Krt5-Cre; R26-stop-tdTomato; Pdgfra-H2B-eGFP mice were hervested. Each specimens were dissociated enzymatically, and then the cell suspensions were sorted by fluorescence-activated cell sorting (FACS) according to eGFP+ and tdTomato+/-. The sorted cells were analyzed using single cell RNA sequencing.

本研究在单细胞转录组层面，对新生皮肤中表皮来源的成纤维细胞展开了探究。研究发现，角蛋白5（Keratin 5）谱系间充质细胞主要呈现出真皮乳头细胞与真皮鞘细胞的转录组特征。本研究数据表明，毛囊真皮细胞最初是通过上皮间质转化（epithelial to mesenchymal transition）由表皮分化而来。
本研究收集了Krt5-Cre；R26-stop-tdTomato；Pdgfra-H2B-eGFP转基因小鼠头部、背部及腹部的新生皮肤组织。随后通过酶解法解离所有标本，制备细胞悬液，并依据eGFP阳性、tdTomato阳性/阴性的标记，采用荧光激活细胞分选术（fluorescence-activated cell sorting, FACS）对细胞进行分群分选。最后对分选出的细胞开展单细胞RNA测序分析。