Hair follicle stem cell cultures reveal self‐organizing plasticity of stem cells and their progeny

The study from 2016 established an in vitro 3D culture system, referred to as 3C, that allowed for the expansion and long-term maintenance of murine hair follicle stem cells (HFSCs). This system enabled the observation of HFSCs self-organizing into a dynamic equilibrium with their progeny, demonstrating bidirectional interconversion between stem cells and non-stem cells. The cultured HFSCs retained their self-renewal capacity and multipotency, as evidenced by their ability to form colonies and reconstitute hair and epidermis in vivo. Transcriptome analysis confirmed that the 3C cultured cells closely resembled in vivo HFSCs. The study also found that specific signaling pathways, such as Shh and BMP, were crucial in mediating the transitions between HFSCs and their progeny, affecting the population dynamics within the culture. The findings have implications for understanding stem cell biology and potential therapeutic applications. The study involved RNA sequencing with 3 to 5 biological replicates and skin reconstitution assays with 4 mice per condition, and mathematical modeling was used to support the conclusions.