Ferroptosis is a form of regulated necrotic cell death controlled by glutathione peroxidase 4 (GPX4). At present, mechanisms that could predict sensitivity and/or resistance and that may be exploited to modulate this form of cell death are needed. We applied two independent approaches, a genome-wide CRISPR-based genetic screen and microarray analysis of ferroptosis-resistant cell lines to uncover acyl-CoA synthetase long-chain family member 4 (Acsl4) as an essential component for ferroptosis execution. Specifically, Gpx4/Acsl4 double knockout cells presented an unprecedented resistance to ferroptosis. Mechanistically, Acsl4 enriches cellular membranes with long polyunsaturated ω6 fatty acids. Moreover, Acsl4 is preferentially expressed in a panel of basal-like breast cancer cell lines and predicts their sensitivity to ferroptosis. We further demonstrate that pharmacological targeting of Acsl4 with the antidiabetic compound class, thiazolidinediones, ameliorates tissue demise in a murine model of ferroptosis, suggesting that Acsl4 inhibition is a viable therapeutic approach to prevent ferroptosis-related diseases.

28Aging is associated with an increased risk of cardiovascular disease and death. Here we 29show that oral supplementation of the natural polyamine spermidine extends the lifespan of 30 mice and exerts cardioprotective effects, reducing cardiac hypertrophy and preserving 31 diastolic function in old mice. Spermidine feeding enhanced cardiac autophagy, mitophagy 32 and mitochondrial respiration, and it also improved the mechano-elastical properties of 33 cardiomyocytes in vivo, coinciding with increased titin phosphorylation and suppressed 34 subclinical inflammation. Spermidine feeding failed to provide cardioprotection in mice that 35 lack the autophagy-related protein Atg5 in cardiomyocytes. In Dahl salt-sensitive rats that 36 were fed a high-salt diet, a model for hypertension-induced congestive heart failure, 37 spermidine feeding reduced systemic blood pressure, increased titin phosphorylation and 38 prevented cardiac hypertrophy and a decline in diastolic function, thus delaying the 39 progression to heart failure. In humans, high levels of dietary spermidine, as assessed from 40 food questionnaires, correlated with reduced blood pressure and a lower incidence of 41 cardiovascular disease. Our results suggest a new and feasible strategy for the protection 42 from cardiovascular disease. 43Author's manuscript to Eisenberg et al.