The fruitfly Drosophila melanogaster as an in vivo model of ferroptosis.

Ferroptosis is an iron-dependent form of cell death involved in cancer, ischemia-reperfusion injury, inflammation, and neurodegeneration. It can be triggered in two ways: class 1 inhibitors such as erastin block system xc-, the cystine/glutamate antiporter composed of xCT and 4F2hc/CD98, causing glutathione depletion, whereas class 2 inhibitors such as RSL3 directly inhibit glutathione peroxidase 4, causing lipid peroxidation. Ferroptotic cell death is suppressed by radical-trapping antioxidants like ferrostatin-1. We investigated the effects of erastin and RSL3 on Drosophila melanogaster lifespan, iron metabolism, and lipid composition. Erastin and RSL3 dose- and diet-dependently shortened lifespan which was rescued by ferrostatin-1. Erastin increased the Fe2+/Fe3+ ratio and reduced ferritin-bound iron, and RSL3 remodeled lipid composition consistent with lipid peroxidation. Both effects occurred only in male w1118 flies although both sexes had similarly reduced lifespans. Total glutathione was unchanged by erastin; notably, the fly GPX4 ortholog Gtpx is a non-selenocysteine, thioredoxin-dependent peroxidase. Complete Gtpx knockout caused early lethality mirroring the embryonic lethality of constitutive GPX4 knockout in mice but was not affected by ferrostatin-1. Flies also lack a clearly defined xCT ortholog. Together, these results establish male w1118 flies as a suitable in vivo ferroptosis model and point to glutathione-independent actions of erastin.