Background

Human follicle dermal papilla cells (HFDPCs) are essential for the induction and maintenance of hair growth 1. Interventions that block the senescence of dermal papilla may effectively expand cell numbers for implantation. However, in vitro culture of HFDPCs has many difficulties in the proliferation and senescence, particularly the lower proliferative capacity 2.

Cellular senescence is caused by a variety of stress and leads to growth arrest. Senescence is associated with declining cellular nicotinamide adenine dinucleotide (NAD+) levels, whereas activation of the NAD+ pathway can extend cellular replicative lifespan 3. AMP‐activated protein kinase (AMPK) is a central regulator of energy homeostasis and was reported to inhibit mTORC1 4 and activate NAD+‐dependent enzymes 3, 5 by increasing cellular NAD+ levels to promote proliferation and prevent senescence.

Recently, we reported that adenine can act as a true AMPK activator following conversion to AMP during purine salvage 6. Proteomic analysis revealed that adenine has a similar effect on NIH‐3T3 cells to another AMPK activator, 5‐aminoimidazole‐4‐carboxamide‐1‐β‐d‐ribofuranoside (AICAR). In this study, we investigated that adenine delays senescence in cultural HFDPC.