Keratinocyte TMEM79 protects early life epidermal homeostasis and restrains STING-dependent skin inflammation

Abstract

Abstract Chronic inflammatory skin diseases are characterized by epithelial barrier dysfunction and immune dysregulation, yet the epithelial-intrinsic mechanisms that initiate inflammation remain poorly understood. TMEM79 is a dermatitis-associated transmembrane protein expressed in keratinocytes, but how its loss promotes skin disease remains unclear. Here, using keratinocyte-specific Tmem79 conditional knockout (cKO) mice and TMEM79-deficient human keratinocytes, we find that TMEM79 is required for proper epithelial differentiation and barrier formation, and that its loss induces keratinocyte stress and ferroptosis-associated lipid peroxidation. Longitudinal analysis of neonatal and early postnatal Tmem79-deficient skin revealed disrupted epidermal homeostasis and early type I IFN signaling preceding the later emergence of type 17 inflammation. Mechanistically, genetic ablation of Sting1, but not Mavs, ameliorated dermatitis and downstream type 17 inflammation, while IL-17A was required for subsequent epidermal hyperplasia. These findings establish STING-dependent signaling as an upstream driver of skin immune activation and pathology. Together, our findings link early-life epithelial stress to innate immune activation and suggest that targeting lipid peroxidation or STING signaling may help prevent inflammatory skin disease progression.

The authors' abstract, as published at the source. PNAS Nexus, 2026 · DOI ↗