Construction of Human Primary Epidermal Organoids and Modeling of Dermatophyte Infection

Despite the strong need for the large-scale generation of human epidermal cells for cell therapy of extensive and severe skin injury, tissue-engineered skin construction and dermatological investigation, the effectiveness of current culture methods is limited and have yet to meet the huge demands sufficiently. Here, we report the establishment of a simple and robust 3D culture system using chemical defined, serum-free medium supplemented with small molecules and growth factors, tailored for human epidermal organoids generation and expansion. The conditions allowed 10,000-fold expansion of the primary epidermal cells within 6 weeks, with the cell architecture and gene expression preserved. We further noticed that only Integrin a6-positive basal stem cells freshly isolated from human epidermis could form expandable epidermal organoids. The epidermal cells inside of the organoids also have the potential to reconstruct multi-layered human epidermis equivalents under classical air-liquid interface condition. Remarkably, the epidermal organoids enable to model the anthropophilic and epidermis-restricted Trichophyton Rubrum infection. This model faithfully mimics and reflects the clinical pathological reactions of reinforced physical barrier by promoting keratinocytes differentiation and accelerated formation of the stratum corneum for adaptation and resistance to infection. Furthermore, the infection model also suggested that constraining host IL-1 signaling may underline the high degree of adaptation of Trichophyton Rubrum to human skin, and the tendency to be chronic and recurrent infection. Thus, human epidermal organoids present a powerful platform for modeling human dermatology, skin tissue engineering and cell therapy. Overall design: Evaluation of whole transcriptome of cells in 2 groups, each of them include 2 replication