Efficacy of Chemokine Receptor Inhibition in Treating IL-36α–Induced Psoriasiform Inflammation

JJ Campbell, K Ebsworth, LS Ertl… - The Journal of …, 2019 - journals.aai.org
JJ Campbell, K Ebsworth, LS Ertl, JP McMahon, Y Wang, S Yau, VR Mali, V Chhina…
The Journal of Immunology, 2019journals.aai.org
Several types of psoriasiform dermatitis are associated with increased IL-36 cytokine activity
in the skin. A rare, but severe, psoriasis-like disorder, generalized pustular psoriasis (GPP),
is linked to loss-of-function mutations in the gene encoding IL-36RA, an important negative
regulator of IL-36 signaling. To understand the effects of IL-36 dysregulation in a mouse
model, we studied skin inflammation induced by intradermal injections of preactivated IL-
36α. We found the immune cells infiltrating IL-36α–injected mouse skin to be of dramatically …
Abstract
Several types of psoriasiform dermatitis are associated with increased IL-36 cytokine activity in the skin. A rare, but severe, psoriasis-like disorder, generalized pustular psoriasis (GPP), is linked to loss-of-function mutations in the gene encoding IL-36RA, an important negative regulator of IL-36 signaling. To understand the effects of IL-36 dysregulation in a mouse model, we studied skin inflammation induced by intradermal injections of preactivated IL-36α. We found the immune cells infiltrating IL-36α–injected mouse skin to be of dramatically different composition than those infiltrating imiquimod-treated skin. The IL-36α–induced leukocyte population comprised nearly equal numbers of CD4+ αβ T cells, neutrophils, and inflammatory dendritic cells, whereas the imiquimod-induced population comprised γδ T cells and neutrophils. Ligands for chemokine receptors CCR6 and CXCR2 are increased in both GPP and IL-36α–treated skin, which led us to test an optimized small-molecule antagonist (CCX624) targeting CCR6 and CXCR2 in the IL-36α model. CCX624 significantly reduced the T cell, neutrophil, and inflammatory dendritic cell infiltrates and was more effective than saturating levels of an anti–IL-17RA mAb at reducing inflammatory symptoms. These findings put CCR6 and CXCR2 forward as novel targets for a mechanistically distinct therapeutic approach for inflammatory skin diseases involving dysregulated IL-36 signaling, such as GPP.
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