Targeted degradation of hepatic KEAP1 mitigates drug-induced liver injury via dual boosting NRF2 and PGAM5 signaling
Oxidative stress and impaired mitochondrial homeostasis are critical drivers of drug-induced liver injury (DILI), both of which are negatively regulated by Kelch-like ECH-associated protein 1 (KEAP1). In this study, a dual-action strategy was adapted to develop a novel KEAP1 degrader with high liver exposure for mitigating DILI through concurrent activation of the NRF2 and PGAM5 signaling pathways. Following screening of a natural product library using complementary KEAP1 thermal shift and NRF2 luciferase reporter assays, cardamonin (CAD) was identified as a natural KEAP1 binder. A series of CAD-derived proteolysis-targeting chimeras (PROTACs) was subsequently designed and synthesized, leading to the discovery of compound 8L that effectively degraded KEAP1 in hepatocytes. In vivo, 8L exhibited marked preferential distribution in the liver, a favorable safety profile, and significant hepatoprotective effects in both acetaminophen- and cisplatin-induced liver injury mouse models. Notably, targeted degradation of hepatic KEAP1 by 8L concurrently activated the NRF2-mediated antioxidative program and the PGAM5-regulated mitochondrial integrity program, which cooperatively restored mitochondrial homeostasis and counteracted oxidative stress. Collectively, a liver-preferential KEAP1 degrader was developed to mitigate DILI by dual activation of the NRF2 and PGAM5 pathways, offering a promising therapeutic agent and more in-depth mechanistic insights into KEAP1-targeted degradation for enhanced anti-DILI therapy.