A STING inhibitor suppresses ferroptosis through radical-trapping antioxidant activity.

Renal ischemia-reperfusion injury (IRI), a leading cause of acute kidney injury, is driven by coordinated inflammatory signaling and ferroptotic cell death, yet effective therapies remain limited. Here, we show that H-151, a covalent stimulator of interferon genes (STING) inhibitor, also suppresses ferroptosis through a STING-independent mechanism. H-151 functions as a broad-spectrum radical-trapping antioxidant that directly scavenges radicals generated during the Fenton reaction, thereby blocking lipid peroxidation. In a murine renal IRI model, H-151 attenuated tissue damage and restored renal function through concurrent inhibition of STING signaling and ferroptosis. These findings establish radical-trapping antioxidant activity as an additional mechanism of H-151 and identify dual inhibition of inflammatory signaling and ferroptosis as a promising therapeutic strategy for IRI and related disorders.