Insight into the mechanism of ferroptosis inhibition by ferrostatin-1

Abstract

Ferroptosis is a form of cell death primed by iron and lipid hydroperoxides and prevented by GPx4. Ferrostatin-1 (fer-1) inhibits ferroptosis much more efficiently than phenolic antioxidants. Previous studies on the antioxidant efficiency of fer-1 adopted kinetic tests where a diazo compound generates the hydroperoxyl radical scavenged by the antioxidant. However, this reaction, accounting for a chain breaking effect, is only minimally useful for the description of the inhibition of ferrous iron and lipid hydroperoxide dependent peroxidation. Scavenging lipid hydroperoxyl radicals, indeed, generates lipid hydroperoxides from which ferrous iron initiates a new peroxidative chain reaction. We show that when fer-1 inhibits peroxidation, initiated by iron and traces of lipid hydroperoxides in liposomes, the pattern of oxidized species produced from traces of pre-existing hydroperoxides is practically identical to that observed following exhaustive peroxidation in the absence of the antioxidant. This supported the notion that the anti-ferroptotic activity of fer-1 is actually due to the scavenging of initiating alkoxyl radicals produced, together with other rearrangement products, by ferrous iron from lipid hydroperoxides. Notably, fer-1 is not consumed while inhibiting iron dependent lipid peroxidation. The emerging concept is that it is ferrous iron itself that reduces fer-1 radical. This was supported by electroanalytical evidence that fer-1 forms a complex with iron and further confirmed in cells by fluorescence of calcein, indicating a decrease of labile iron in the presence of fer-1. The notion of such as pseudo-catalytic cycle of the ferrostatin-iron complex was also investigated by means of quantum mechanics calculations, which confirmed the reduction of an alkoxyl radical model by fer-1 and the reduction of fer-1 radical by ferrous iron. In summary, GPx4 and fer-1 in the presence of ferrous iron, produces, by distinct mechanism, the most relevant anti-ferroptotic effect, i.e the disappearance of initiating lipid hydroperoxides.

xCT Inhibition Increases Sensitivity to Vorinostat in a ROS-Dependent Manner

“…We then considered ferroptosis because SASP is known to be a ferroptosis inducer [20][21][22][23]. As expected, both ferrostatin-1 [35,36] and liproxstatin-1 [35], known ferroptosis inhibitors, attenuated cell death induced by the combination of vorinostat and SASP ( Figure 6C), suggesting that combined vorinostat and SASP induced ferroptosis. Moreover, the cleavage of PARP (poly (ADP-ribose) polymerase) was not induced after the combination treatment ( Figure 6B), suggesting that cotreatment of vorinostat with SASP did not induce caspase-dependent apoptosis.…”

Iron derived from autophagy-mediated ferritin degradation induces cardiomyocyte death and heart failure in mice

“…The labile iron pool level was measured using calcein-acetoxymethyl ester ( Yoshida et al, 2019 ). Erastin and isoproterenol could both increase the level of the labile iron pool in Ncoa4 +/+ cardiomyocytes, which was attenuated by treatment with ferrostatin-1 ( Miotto et al, 2020 ; Figure 5D and Figure 5—figure supplement 1D ). Ncoa4 ablation was effective in reducing the erastin- or isoproterenol-induced upregulation of the labile iron pool.…”

Chondrocyte ferroptosis contribute to the progression of osteoarthritis

“…Ferrostatin-1 is an efficient ferroptosis specific inhibitor functioned by eliminating the initiating alkoxyl radicals and other rearrangement products that produced by ferrous iron from lipid hydroperoxides [ 36 ]. We used Ferrostatin-1 to verify the existence of ferroptosis in IL-1β and FAC treated chondrocytes.…”