Wnt1a maintains characteristics of dermal papilla cells that induce mouse hair regeneration in a 3D preculture system.

Hair follicle morphogenesis and regeneration depend on intensive but well-orchestrated interactions between epithelial and mesenchymal components. Therefore, an alternative strategy to reproduce the process of epithelial–mesenchymal interaction in vitro could use a 3D system containing appropriate cell populations. The 3D air–liquid culture system for reproducibly generating hair follicles from dissociated epithelial and dermal papilla (DP) cells combined with a collagen–chitosan scaffold is described in this study. Wnt-CM was prepared from the supernatant of Wnt1a-expressing bone marrow mesenchymal stem cells (BM-MSCs) that maintain the hair-inducing gene expression of DP cells. The collagen–chitosan scaffold cells (CCS cells) were constructed using a two-step method by inoculating the Wnt-CM-treated DP cells and epidermal (EP) cells into the CCS. The cells in the air–liquid culture formed dermal condensates and a proliferative cell layer in vitro. The CCS cells were able to induce hair regeneration in nude mice. The results demonstrate that Wnt-CM can maintain the hair induction ability of DP cells in expansion cultures, and this approach can be used for large-scale preparation of CCS cells in vitro to treat hair loss. Copyright © 2015 John Wiley & Sons, Ltd.