Discovering selective antiferroptotic inhibitors of the 15LOX/PEBP1 complex noninterfering with biosynthesis of lipid mediators

Programmed ferroptotic death eliminates cells in all major organs and tissues with imbal-anced redox metabolism due to overwhelming iron-catalyzed lipid peroxidation under insufficient control by thiols (Glutathione (GSH)). Ferroptosis has been associated with the pathogenesis of major chronic degenerative diseases and acute injuries of the brain, cardiovascular system, liver, kidneys, and other organs, and its manipulation offers a prom-ising new strategy for anticancer therapy. This explains the high interest in designing new small-molecule-specific inhibitors against ferroptosis. Given the role of 15-lipoxygenase (15LOX) association with phosphatidylethanolamine (PE)- binding protein 1 (PEBP1) in initiating ferroptosis-specific peroxidation of polyunsaturated PE, we propose a strategy of discovering antiferroptotic agents as inhibitors of the 15LOX/PEBP1 catalytic complex rather than 15LOX alone. Here we designed, synthesized, and tested a customized library of 26 compounds using biochemical, molecular, and cell biology models along with redox lipidomic and computational analyses. We selected two lead compounds, FerroLOXIN- 1 and 2, which effectively suppressed ferroptosis in vitro and in vivo without affecting the biosynthesis of pro- /anti-inflammatory lipid mediators in vivo. The effectiveness of these lead compounds is not due to radical scavenging or iron-chelation but results from their specific mechanisms of interaction with the 15LOX- 2/PEBP1 complex, which either alters the binding pose of the substrate [eicosatetraenoyl- PE (ETE- PE)] in a nonproductive way or blocks the predominant oxygen channel thus preventing the catalysis of ETE- PE peroxidation. Our successful strategy may be adapted to the design of additional chemical libraries to reveal new ferroptosis-targeting therapeutic modalities.

Automated summary

Programmed ferroptotic death eliminates cells in all major organs and tissues through iron-catalyzed lipid peroxidation under inadequate control by thiols. Ferroptosis is associated with the development of chronic degenerative diseases and acute injuries in various organs, making it a potential target for therapeutic intervention. The study focuses on inhibiting the catalytic complex of 15-lipoxygenase (15LOX) and phosphatidylethanolamine (PE)-binding protein 1 (PEBP1), rather than 15LOX alone, as a strategy to discover antiferroptotic agents. The design and testing of a customized library of compounds led to the identification of two lead compounds, FerroLOXIN-1 and 2, which effectively suppress ferroptosis in vitro and in vivo by interacting with the 15LOX-2/PEBP1 complex.