IL‐36 receptor antagonistic antibodies inhibit inflammatory responses in preclinical models of psoriasiform dermatitis

Psoriasis vulgaris (PV) results from activation of IL‐23/Th17 immune pathway and is further amplified by cytokines/chemokines from skin cells. Among skin‐derived pro‐inflammatory cytokines, IL‐36 family members are highly upregulated in PV patients and play a critical role in general pustular psoriasis. However, there is limited data showing crosstalk between the IL‐23 and IL‐36 pathways in PV. Herein, potential attenuation of skin inflammation in the IL‐23‐induced mouse model of psoriasiform dermatitis by functional inhibition of IL‐36 receptor (IL‐36R) was interrogated. Anti‐mouse IL‐36R monoclonal antibodies (mAbs) were generated and validated in vitro by inhibiting IL‐36α‐induced secretion of CXCL1 from NIH 3T3 cells. Antibody target engagement was demonstrated by inhibition of CXCL1 production in a novel acute model of IL‐36α systemic injection in mice. In addition, anti‐IL‐36R mAbs inhibited tissue inflammation and inflammatory gene expression in an IL‐36α ear injection model of psoriasiform dermatitis demonstrating engagement of the target in the ear skin. To elucidate the possible role of IL‐36 signalling in IL‐23/Th17 pathway, the ability of anti‐IL‐36R mAbs to inhibit skin inflammation in an IL‐23 ear injection model was assessed. Inhibiting the IL‐36 pathway resulted in significant attenuation of skin thickening and psoriasis‐relevant gene expression. Taken together, these data suggest a role for IL‐36 signalling in the IL‐23/Th17 signalling axis in PV.