Keratinocyte-derived IκBζ drives psoriasis and associated systemic inflammation
Sebastian Lorscheid, Anne Müller, Jessica Löffler, Claudia Resch, Philip Bucher, Florian C. Kurschus, Ari Waisman, Knut Schäkel, Stephan Hailfinger, Klaus Schulze-Osthoff, Daniela Kramer
Sebastian Lorscheid, Anne Müller, Jessica Löffler, Claudia Resch, Philip Bucher, Florian C. Kurschus, Ari Waisman, Knut Schäkel, Stephan Hailfinger, Klaus Schulze-Osthoff, Daniela Kramer
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Research Article Dermatology

Keratinocyte-derived IκBζ drives psoriasis and associated systemic inflammation

Abstract

The transcriptional activator IκBζ is a key regulator of psoriasis, but which cells mediate its pathogenic effect remains unknown. Here we found that IκBζ expression in keratinocytes triggers not only skin lesions but also systemic inflammation in mouse psoriasis models. Specific depletion of IκBζ in keratinocytes was sufficient to suppress the induction of imiquimod- or IL-36–mediated psoriasis. Moreover, IκBζ ablation in keratinocytes prevented the onset of psoriatic lesions and systemic inflammation in keratinocyte-specific IL-17A–transgenic mice. Mechanistically, this psoriasis protection was mediated by IκBζ deficiency in keratinocytes abrogating the induction of specific proinflammatory target genes, including Cxcl5, Cxcl2, Csf2, and Csf3, in response to IL-17A or IL-36. These IκBζ-dependent genes trigger the generation and recruitment of neutrophils and monocytes that are needed for skin inflammation. Consequently, our data uncover a surprisingly pivotal role of keratinocytes and keratinocyte-derived IκBζ as key mediators of psoriasis and psoriasis-related systemic inflammation.

Authors

Sebastian Lorscheid, Anne Müller, Jessica Löffler, Claudia Resch, Philip Bucher, Florian C. Kurschus, Ari Waisman, Knut Schäkel, Stephan Hailfinger, Klaus Schulze-Osthoff, Daniela Kramer

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Figure 3

Analysis of skin-infiltrating T cells in IMQ-treated K14-IκBζ–KO mice.

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Analysis of skin-infiltrating T cells in IMQ-treated K14-IκBζ–KO mice. A...
All analyses were performed after 7 days of IMQ treatment. (A) Flow cytometry analysis of T cell subsets in the ears of IMQ-treated Ctrl and K14-KO mice. T cell subsets were detected as CD45+ and CD3+, αβTCR+, or γδTCR+ cells. Single data points derive from 2 ears. Shown is the mean of 4–12 mice per group ± SEM. (B) Gene expression analysis of Il22 and Il17a in skin tissue of untreated and IMQ-treated control and K14-KO mice, normalized to the reference gene Actin. n = 4–14 ± SEM. (C) Determination of the percentage of IL-17A– and IL-22–producing αβ and γδ T cells in IMQ-treated control and K14-KO mice. After fixation and permeabilization, cells were gated as in A, except for an additional gating on either IL-17A+ or IL-22+ cells. n = 3 ± SEM. (D) Gene expression analysis of Il1b and Il23a in untreated and IMQ-treated mice, similar as in B. (E) mRNA levels of Ccl2, Ccl17, and Ccl20 in untreated mice, similar as in B. (F) mRNA levels of Ccr2, Ccr4, and Ccr6 in the skin of untreated control and K14-KO mice, similar as in B. n = 5–14 ± SEM. P values were calculated using 2-tailed Student’s t test (*P < 0.05, **P < 0.01, and ***P < 0.001).