Abstract
Epithelial cells have been shown to express the antibiotic peptides human β-defensins-1 and 2. While β-defensin-2 is known to be up-regulated by bacterial factors and proinflammatory mediators, the expression of β-defensin-1 does not appear to be affected by these mediators. To determine the regulation and function of β-defensin-1 we analyzed its expression upon stimulation of inflammatory mediators in vitro and ex vivo. In immortalized human cell lines (HaCaT) and nasal polyps β-defensin-1 was not induced upon incubation with bacteria or proinflammatory mediators, suggesting that the inertness of β-defensin-1 expression levels is not the result of the shortcoming of HaCaT cells. As proliferation and regeneration play an important role at sites of inflammation, we examined the expression level of β-defensin-1 in relation to the differentiation and proliferation of HaCaT cells. β-defensin-1 mRNA levels remained low during proliferation but were highly induced upon differentiation. In contrast, β-defensin-2 expression was unaffected under these conditions. To examine the function of β-defensin-1 in cellular proliferation and differentiation processes β-defensin-1 was overexpressed in keratinocytes. Protein expression analysis of the differentiation marker keratin 10 revealed that its expression is highly induced in the presence of increased concentrations of β-defensin-1. Hence our data indicate that high expression of β-defensin-1 promotes cell differentiation processes of keratinocytes.
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Frye, M., Bargon, J. & Gropp, R. Expression of human β-defensin-1 promotes differentiation of keratinocytes. J Mol Med 79, 275–282 (2001). https://doi.org/10.1007/s001090100200
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DOI: https://doi.org/10.1007/s001090100200