993 CARD14 gain-of-function mutation alone is sufficient to drive IL-23/IL-17-mediated psoriasiform skin inflammation in vivo

Abstract

Rare missense mutations in the gene encoding the keratinocyte signaling molecule, Caspase Recruitment Domain-Containing Protein 14 (CARD14), have been associated with an increased susceptibility to chronic inflammatory skin diseases, psoriasis and pityriasis rubra pilaris. However, the physiological impact of CARD14 gain-of-function mutations as drivers of disease pathogenesis remains to be fully determined in vivo. Here, we report that heterozygous mice harboring a CARD14 gain-of-function mutation (Card14ΔE138) spontaneously develop a chronic psoriatic phenotype with characteristic scaling skin lesions, epidermal thickening, keratinocyte hyperproliferation, hyperkeratosis and immune cell infiltration. Affected skin of these mice is characterized by elevated expression of anti-microbial peptides, chemokines and cytokines (including Th17 cell-signature cytokines), and an immune infiltrate rich in neutrophils, myeloid cells and T-cells, reminiscent of human psoriatic skin. Disease pathogenesis was driven by the IL-23/IL-17 axis and neutralization of IL-23p19, the key cytokine in maintaining Th17 cell polarization, significantly reduced skin lesions and the expression of pro-inflammatory molecules. Therefore, hyperactivation of the keratinocyte signaling molecule CARD14 alone is sufficient to orchestrate the complex immunopathogenesis that drives Th17-mediated psoriatic skin disease in vivo.