IKKβ Leads to an Inflammatory Skin Disease Resembling Interface Dermatitis

IKK beta is a subunit of the I kappa B kinase (IKK) complex required for NF-kappa B activation in response to pro-inflammatory signals. NF-kappa B regulates the expression of many genes involved in inflammation, immunity, and apoptosis, and also controls cell proliferation and differentiation in different tissues; however, its function in skin physiopathology remains controversial. In this study we report the alterations caused by increased IKK beta activity in skin basal cells of transgenic mice. These animals suffered chronic inflammation with abundant macrophages and other CD45(+) infiltrating cells in the skin, which resulted in epidermal basal cell injury and degeneration of hair follicles. They showed histological features characteristic of interface dermatitis (ID). This phenotype is accompanied by an increased production of inflammatory cytokines by transgenic keratinocytes. Accordingly, transcriptome studies show upregulation of genes associated with inflammatory responses. The inflammatory phenotype observed as a consequence of IKK beta overexpression is independent of T and B lymphocytes, as it also arises in mice lacking these cell types. In summary, our data indicate the importance of IKK beta in the development of ID and in the homeostasis of stratified epithelia. Our results also support the idea that IKK beta might be a valid therapeutic target for the treatment of skin inflammatory diseases.