Targeting eIF5A hypusination prevents anoxic cell death through mitochondrial silencing and improves kidney transplant outcome

Abstract

Theeukaryotic initiation factor5A(eIF5A),which ishighlyconservedthroughoutevolution,has theuniquecharacteristic of post-Translational activation through hypusination. This modification is catalyzed by two enzymatic steps involving deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH). Notably, eIF5A may be involved in regulating the lifespan of Drosophila during long-Term hypoxia. Therefore,we investigated the possibility of a link between eIF5A hypusination and cellular resistance to hypoxia/anoxia. Pharmacologic targeting of DHPS by N1-guanyl-1,7- diaminoheptane (GC7) or RNA interference-mediated inhibition of DHPS or DOHH induced tolerance to anoxia in immortalized mouse renal proximal cells. Furthermore, GC7 treatment of cells reversibly induced a metabolic shift toward glycolysis aswell as mitochondrial remodeling and led to downregulated expression and activity of respiratory chain complexes, features characteristic of mitochondrial silencing. GC7 treatment also attenuated anoxia-induced generation of reactive oxygen species in these cells and in normoxic conditions, decreased the mitochondrial oxygen consumption rateof culturedcellsandmice. In rats, intraperitoneal injection ofGC7substantiallyreducedrenal levels of hypusinatedeIF5Aandprotected against ischemia-reperfusion-induced renal injury.Finally, inthepreclinical pig kidney transplant model, intravenous injection of GC7 before kidney removal significantly improved graft function recovery and late graft function and reduced interstitial fibrosis after transplant. This unconventional signaling pathway offers an innovative therapeutic target for treating hypoxic-ischemic human diseases and organ transplantation.