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 dermal papilla plays an important role in the regulation of hair follicle matrix cell proliferation and hair fiber production, at least in part through mesenchymal-epithelial interactions. In the present study, we have investigated the regulation of interleukin-1 (IL-1) production by protein kinase C in cultured human dermal papilla cells. Treatment of dermal papilla cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) elicited the rapid and transient production of mature (17 kDa) cytosolic IL-1β protein, but not IL-1α, with maximal levels achieved after 12 h. Rapid secretion of IL-1β into the medium occurred subsequent to increased intracellular cytokine levels, after which medium IL-1β protein levels were stable for 4 days. Northern blot analysis showed that TPA treatment elicited a transient induction of IL-1β mRNA expression, maximal after 12 h, indicating that TPA regulates dermal papilla cell IL-1β production at the transcriptional level. Pretreatment of dermal papilla cells with Ro 31-7549, a ...