IL-1 alpha inhibits human hair follicle growth and hair fiber production in whole-organ cultures.
In this study we have used a recently developed human hair follicle whole-organ culture system to investigate the effect of IL-1 alpha on hair follicle growth and hair fiber production. In the presence of 10 ng/ml IL-1 alpha, the growth of cultured human hair follicles ceased within 2-4 days, whereas control hair follicles grew for a period of 7-10 days. IL-1 alpha also inhibited hair fiber growth, but with an onset which occurred 3 days later than that of follicle growth inhibition. An IC50 value of approximately 30 pg/ml was obtained for IL-1 alpha inhibition of follicle growth. Incubation of hair follicles with IL-1 alpha resulted in a rapid, transient reduction in the rate of whole-follicle DNA synthesis. 1000-fold molar excess of IL-1 receptor antagonist prevented IL-1-induced follicle growth inhibition, while antagonist alone was without effect. The selective PKC inhibitor, Ro 31-7549, augmented IL-1-induced inhibition of hair follicle growth, but did not itself affect hair follicle growth. These findings indicate that IL-1 alpha exerts a rapid antiproliferative effect on hair follicles, and that inhibition of hair fiber growth is a secondary response. Thus, IL-1 may play a role in the pathophysiology of inflammatory hair loss conditions, such as alopecia areata, through a direct growth-inhibitory effect on hair follicles.
Harmon
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Hoffmann-La Roche Inc., Nutley, NJ 07110.
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D002455:Cell Division / Q000187:drug effects; D004247:DNA / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D006197:Hair / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D007700:Kinetics; D009924:Organ Culture Techniques; D011994:Recombinant Proteins / Q000494:pharmacology; D013936:Thymidine / Q000378:metabolism; D013997:Time Factors
D007375:Interleukin-1; D011994:Recombinant Proteins; D004247:DNA; D013936:Thymidine