Epidermal keratinocytes contain 15-lipoxygenase, which generates 15-hydroxyeicosatetraenoic acid, a major metabolite of arachidonic acid. Although two isozymes, 15-lipoxygenase-1 and -2, exist, it remains unclear which isozyme plays an important role in inflammatory processes and proliferative skin diseases. In the present study, we demonstrated that 15-lipoxygenase-2 expression was increased in normal human epidermal keratinocytes and HaCaT cells treated with interferon-γ (200 U/ml), while no induction of 15-lipoxygenase-1 was observed. Under the same culture conditions, no 15-lipoxygenase-2 was expressed by a carcinoma cell line, A431. Weak expression of 15-lipoxygenase-2 was observed in the basal cell layer of non-lesional psoriatic skin by in situ hybridization and immunostaining, whereas strong expression of 15-lipoxygenase-2 was observed in all living layers of psoriatic lesions. Actinic keratosis and squamous cell carcinomas showed a variable immunostaining pattern for 15-lipoxygenase-2. These results indicate that 15-lipoxygenase-2 is implicated in interferon-γ-induced inflammatory processes in normal human epidermal keratinocytes and psoriatic skin.
|Number of pages||5|
|Journal||European Journal of Dermatology|
|Publication status||Published - Mar 2006|
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