ATG9A-mediated autophagy prevents inflammatory skin disease by limiting TNFR1-driven STING activation and ZBP1-dependent cell death.

Tumor necrosis factor (TNF) is a central pro-inflammatory cytokine with pathologic roles in chronic inflammatory and autoimmune disorders. The mechanisms by which TNF sensing drives the pathogenesis of these diseases are not fully understood. We previously showed that the lack of the autophagic lipid scramblase ATG9A in mouse keratinocytes leads to severe dermatitis and systemic inflammation, with features resembling human skin disorders. We now demonstrate that the disease is initiated by TNF but caused by cGAS/STING-dependent type I interferon (IFN) production and subsequent ZBP1-dependent apoptosis and necroptosis. ATG9A prevented the pathogenesis of the disease by engaging both light-chain 3 (LC3)-dependent and -independent autophagy. These results uncover an additional pathological arm of TNF signaling, opening avenues for alternative therapeutic interventions for TNF-driven diseases. Moreover, this study reveals another pathophysiological function of LC3-independent autophagy in restraining type I IFN production, which triggers the development or exacerbation of an interferonopathy in mice and humans.