Discovery of a novel quinoline RIP1 inhibitor and its treatment of acute liver injury in mice

Necroptosis is closely associated with the development of inflammatory diseases, including acute liver injury. However, the precise role of necroptosis-related signature proteins in acute liver injury remains incompletely understood. Previously, our group investigated Compound o1, a RIP1 inhibitor, but its antinecroptosis activity and RIP1 binding affinity were suboptimal. In this study, we sought to address these two critical scientific challenges. Through a scaffold-hopping strategy, we identified a series of novel quinoline-like RIP1 inhibitors, among which N-1 exhibited the most potent antinecroptosis activity and the strongest RIP1 binding affinity. N-1 effectively inhibited necrosome formation by blocking phosphorylation in the RIP1/RIP3/MLKL signaling pathway. In a TNF-induced hypothermia mouse model of systemic inflammatory response syndrome (SIRS), N-1 significantly improved the survival rate of mice in a dose-dependent manner. Our study further revealed that RIP1, RIP3, and MLKL are expressed in normal liver tissues, whereas their phosphorylated forms (pRIP1, pRIP3, and pMLKL) are absent. In contrast, liver tissues from mice with CCl₄-induced acute liver injury exhibited high expression levels of pRIP1, pRIP3, and pMLKL, indicating that Necroptosis is associated with liver injury. N-1 significantly inhibited the phosphorylation of RIP1, RIP3, and MLKL, while restoring key liver damage markers such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST). These findings suggest that targeting Necroptosis may represent a promising therapeutic strategy for the treatment of acute liver injury.

Necroptosis，RIP1 inhibitor，acute liver injury.