ABSTRACT
Suitable human models for the development and characterization of topical compounds for inflammatory skin diseases such as atopic dermatitis are not readily available to date. We describe here the development of a translational model involving healthy human skin mimicking major aspects of AD and its application for the characterization of topical Janus kinase inhibitors. Full thickness human abdominal skin obtained from plastic surgery stimulated in vitro with IL4 and IL13 shows molecular features of AD. This is evidenced by STAT6 phosphorylation assessed by immunohistochemistry and analysis of skin lysates. Broad transcriptome changes assessed by AmpliSeq followed by gene set variation analysis showed a consistent upregulation of gene signatures characterizing AD in this model. Topical application of experimental formulations of compounds targeting the JAK pathway to full thickness skin normalizes the molecular features of AD induced by IL4 and IL13 stimulation. The inhibitory effects of topical JAK inhibitors on molecular features of AD are supported by pharmacokinetic analysis. The model described here is suited for the characterization of topical compounds for AD and has the potential to be extended to other inflammatory skin diseases and pathophysiological pathways.
Subject(s)
Dermatitis, Atopic , Janus Kinase Inhibitors , Skin , Humans , Dermatitis, Atopic/drug therapy , Skin/metabolism , Skin/drug effects , Janus Kinase Inhibitors/pharmacology , STAT6 Transcription Factor/metabolism , Interleukin-4/metabolism , Interleukin-13/metabolism , Phosphorylation , Transcriptome , Models, Biological , Pyrimidines/pharmacology , Administration, Topical , PiperidinesABSTRACT
When SUCNR1/GPR91-expressing macrophages are activated by inflammatory signals, they change their metabolism and accumulate succinate. In this study, we show that during this activation, macrophages release succinate into the extracellular milieu. They simultaneously up-regulate GPR91, which functions as an autocrine and paracrine sensor for extracellular succinate to enhance IL-1ß production. GPR91-deficient mice lack this metabolic sensor and show reduced macrophage activation and production of IL-1ß during antigen-induced arthritis. Succinate is abundant in synovial fluids from rheumatoid arthritis (RA) patients, and these fluids elicit IL-1ß release from macrophages in a GPR91-dependent manner. Together, we reveal a GPR91/succinate-dependent feed-forward loop of macrophage activation and propose GPR91 antagonists as novel therapeutic principles to treat RA.
