CHIH-CHIEH CHANFan, Sabrina Mai-YiSabrina Mai-YiFanWang, Wei-HungWei-HungWangMu, Yi-FenYi-FenMuSUNG-JAN LIN2022-09-162022-09-1620151937-3384https://www.scopus.com/inward/record.uri?eid=2-s2.0-84942901177&doi=10.1089%2ften.tec.2015.0033&partnerID=40&md5=92dea0d980c70f8c12000f74a3d37897https://scholars.lib.ntu.edu.tw/handle/123456789/620679Successful hair follicle (HF) neogenesis in adult life depends on the existence of both capable dermal cells and competent epidermal keratinocytes that recapitulate embryonic organogenesis through epithelial-mesenchymal interaction. In tissue engineering, the maintenance of trichogenic potential of adult epidermal cells, while expanding them remains a challenging issue. We found that although HF outer root sheath keratinocytes could be expanded for more than 100 passages as clonogenic cells without losing the proliferative potential with a 3T3J2 fibroblast feeder layer, these keratinocytes were unable to form new HFs when combined with inductive HF dermal papilla (DP) cells. However, when these high-passage keratinocytes were cocultured with HF DP cells for 4 days in vitro, they regained the trichogenic ability to form new HFs after transplantation. We found that the short-term coculture with DP cells enhanced both Wnt/β-catenin signaling, a signaling cascade key to HF development, and upregulated the expression of HF-specific genes, including K6, K16, K17, and K75, in keratinocytes, indicating that these cells were poised toward a HF fate. Hence, efficient production of trichogenic keratinocytes can be obtained by a two-stepped procedure with initial cell expansion with a 3T3J2 fibroblast feeder followed by short-term coculture with DP cells. © Copyright 2015, Mary Ann Liebert, Inc. 2015.enjournal article10.1089/ten.tec.2015.0033259511882-s2.0-84942901177