BMI1 Is Required for Melanocyte Stem Cell Maintenance and Hair Pigmentation

The study reveals that the epigenetic repressor BMI1 is essential for maintaining melanocyte stem cells (McSCs) and hair pigmentation in mice. Deletion of Bmi1 led to premature hair greying, loss of melanocyte lineage cells, and increased stress sensitivity. RNA sequencing showed that Bmi1 deletion upregulated Cdkn2a, increasing p16Ink4a and p19Arf expression, and downregulated oxidative stress-related enzymes Gsta1 and Gsta2. Treatment with the antioxidant N-acetyl cysteine partially rescued melanocyte expansion. The findings underscore BMI1's role in protecting McSCs from stress and maintaining hair pigmentation through both canonical and non-canonical pathways.