Mediator 1 Ablation Induces Enamel-to-Hair Lineage Conversion in Mice Through Enhancer Dynamics

The study investigated the role of Mediator 1 (Med1) in controlling cell lineage development in mice. Researchers found that removing Med1 in ectoderm-derived epithelial cells led to hair growth on the incisors and loss of enamel production, due to a reshaping of the enhancer landscape. This suggests that Med1 deficiency can switch the dental transcriptional program towards hair and epidermis in incisors. In vitro, Med1 deletion in dental epithelial stem cells (DE-SCs) led to an increased proliferation rate and spontaneous differentiation into the epidermal lineage. The loss of Med1 also led to significant changes in the enhancer landscape in DE-SCs, linked to functions such as enamel mineralization, tooth morphogenesis, and hair development. The findings suggest potential new strategies for the regeneration of tissues like tooth enamel and skin hair.