Exploration of Immunology (Apr 2021)

Interleukin-22 and keratinocytes; pathogenic implications in skin inflammation

  • Masutaka Furue,
  • Mihoko Furue

DOI
https://doi.org/10.37349/ei.2021.00005
Journal volume & issue
Vol. 1, no. 1
pp. 37 – 47

Abstract

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Interleukin (IL)-22 is produced from immune cells such as T helper (Th)22 cells, Th17/22 cells, and group 3 innate lymphoid cells. IL-22 signals via the IL-22 receptor 1 (IL-22R1) and the IL-10 receptor 2 (IL-10R2). As the IL-22R1/IL-10R2 heterodimer is preferentially expressed on border tissue between the host and the environment, IL-22 is believed to be involved in border defense. Epidermal keratinocytes are the first-line skin barrier and express IL-22R1/IL-10R2. IL-22 increases keratinocyte proliferation but inhibits differentiation. Aryl hydrocarbon receptor (AHR) is a chemical sensor and an essential transcription factor for IL-22 production. In addition, AHR also upregulates the production of barrier-related proteins such as filaggrin in keratinocytes, suggesting a pivotal role for the AHR-IL-22 axis in regulating the physiological skin barrier. Although IL-22 signatures are elevated in atopic dermatitis and psoriasis, their pathogenic and/or protective implications are not fully understood.

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