The cGAS-STING pathway drives type I IFN immunopathology in COVID-19 – Nature

Coronavirus disease 2019 (COVID-19), caused by infection with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), is characterized by significant lung pathology and extrapulmonary complications^1,2. Type I interferons (IFNs) play an essential role in the pathogenesis of COVID-19^3–5. While rapid induction of type I IFNs limits virus propagation, sustained elevation of type I IFNs in the late phase of the infection is associated with aberrant inflammation and poor clinical outcome^5–17. Here, we identify the cyclic GMP-AMP synthase (cGAS)-Stimulator of interferon genes (STING)-pathway, which controls immunity to cytosolic DNA, as a critical driver of aberrant type I IFN responses in COVID-19¹⁸. Profiling COVID-19 skin manifestations, we uncover a STING-dependent type I IFN signature primarily mediated by macrophages adjacent to areas of endothelial cell damage. Moreover, cGAS-STING activity was detected in lung samples of COVID-19 patients with prominent tissue destruction and associated with type I IFN responses. A lung-on-chip model revealed that, in addition to macrophages, SARS-CoV-2 infection activates cGAS-STING signalling in endothelial cells through mitochondrial DNA release, leading to cell death and type I IFN production. In mice, pharmacological inhibition of STING reduces severe lung inflammation induced by SARS-CoV-2 and improves disease outcome. Collectively, our study establishes a mechanistic basis of pathological type I IFN responses in COVID-19 and reveals a novel principle for the development of host-directed therapeutics.