Interleukin-1β Is Differentially Expressed by Human Dermal Papilla Cells in Response to PKC Activation and Is a Potent Inhibitor of Human Hair Follicle Growth in Organ Culture

The study investigated the regulation of interleukin-1β (IL-1β) production by protein kinase C in cultured human dermal papilla cells and its effect on hair follicle growth. Treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) induced rapid and transient production of IL-1β, with peak levels at 12 hours, and secretion into the medium, where levels remained stable for 4 days. This production was regulated at the transcriptional level and could be inhibited by a protein kinase C inhibitor. IL-1β was found to be a potent inhibitor of human hair follicle growth in organ culture, with an IC50 value of approximately 5 pg/ml. The findings suggested that IL-1β from dermal papilla cells might act as a negative paracrine factor in regulating hair matrix cell proliferation.