Beyond the Epidermal-Melanin-Unit: The Human Scalp Anagen Hair Bulb Is Home to Multiple Melanocyte Subpopulations of Variable Melanogenic Capacity

The study "Beyond the Epidermal-Melanin-Unit: The Human Scalp Anagen Hair Bulb Is Home to Multiple Melanocyte Subpopulations of Variable Melanogenic Capacity" discovered multiple melanocyte subpopulations in the human scalp hair bulb, each with varying capacities for melanin production. Using c-KIT/CD117 microbeads, researchers isolated two melanocyte subpopulations: one expressing both MITF and SOX10, and another expressing only MITF. A third 'immature' melanocyte population was also identified, which was c-KIT/MITF double-positive but SOX10 negative. The study also found that Dopachrome Tautomerase (DCT/TRP-2) is expressed by melanocytes in the human scalp hair bulb, which can be further upregulated by inflammatory and UVR stressors. These findings suggest a functional diversity in the human scalp hair follicle, beyond the traditional view of melanocyte functionality as the capacity to produce melanin.