Discovery of bardoxolone derivatives as novel orally active necroptosis inhibitors

Necroptosis is a form of programmed cell death that contributes to the pathophysiology of cerebral ischemia/reperfusion (I/R) injury. In this study, bardoxolone (CDDO, 7) was an inhibitor of necroptosis identified from an in-house natural product library. Further optimization led to identify a more potent analogue 20. Compound 20 could effectively protect against necroptosis in human and mouse cells. The antinecroptotic effect could also be synergized with other necroptosis inhibitors. It blocked necrosome formation by targeting Hsp90 to inhibit the phosphorylation of RIPK1 and RIPK3 in necroptotic cells. In vivo, this compound was orally active to alleviate TNF-induced systemic inflammatory response syndrome (SIRS) and cerebral I/R injury. Our results suggested that 20 could be a lead compound for discovering necroptosis inhibitors in I/R treatment.