Dermal Papilla Cells and Melanocytes Response to Physiological Oxygen Levels Depends on Their Interactions

The study explored the effects of physiological oxygen levels (physoxia) on human dermal papilla (DP) cells and melanocytes (hMel), both individually and in co-culture systems. Physoxia was found to reduce senescence in DP cells, enhance their secretome and phenotype, and increase hMel proliferation, migration, and tyrosinase activity. While indirect co-culture under physoxia did not significantly affect hMel proliferation or tyrosinase activity, direct co-culture in 3D aggregates resulted in increased functional indicators for both hMel and DP cells, such as tyrosinase and alkaline phosphatase (ALP) activities, along with higher reactive oxygen species (ROS) production. The study suggests that the microenvironment created by direct contact between hMel and DP cells under physoxia is beneficial for their functions, which may have implications for hair regeneration. Specific sample sizes were not provided, except for a mention of n = 3 for most tests and n = 6 for DNA quantification in one instance.