The IL-13/periostin/IL-24 pathway causes epidermal barrier dysfunction in allergic skin inflammation

Area of Science:

• Dermatology
• Immunology
• Molecular Biology

Background:

• Atopic dermatitis (AD) is characterized by skin barrier dysfunction.
• Type 2 cytokines, such as IL-4 and IL-13, are implicated in AD pathogenesis.
• Periostin, induced by IL-4/IL-13, is crucial for allergic skin inflammation but its downstream effects on barrier function are unclear.

Purpose of the Study:

• To elucidate the mechanism by which periostin mediates IL-13-induced barrier dysfunction in AD.
• To identify downstream molecules in the IL-13/periostin signaling pathway.
• To investigate the role of IL-24 in filaggrin downregulation and skin barrier defects.

Main Methods:

• DNA microarrays to identify periostin-dependent gene expression profiles.
• In vitro studies using keratinocytes to assess IL-24's effect on filaggrin expression.
• JAK/STAT pathway analysis for IL-13-induced IL-24 and IL-24-induced filaggrin changes.
• In vivo studies in mite-treated mice and analysis of human AD skin samples.

Main Results:

• IL-24 was identified as a key IL-13-induced molecule, dependent on periostin and STAT6 signaling in keratinocytes.
• IL-24 significantly downregulated filaggrin expression through STAT3 activation, leading to barrier dysfunction.
• Elevated IL-24 expression and STAT3 activation were observed in mite-treated mice and human AD skin, downstream of IL-13/periostin.

Conclusions:

• The IL-13/periostin pathway stimulates keratinocyte IL-24 production.
• IL-24 plays a critical role in mediating skin barrier dysfunction in atopic dermatitis.
• Targeting the IL-13/periostin/IL-24 axis may offer therapeutic strategies for AD.