Further studies confirmed that erastin induced ferroptosis by GSH down-regulation caused by depletion of intracellular cysteine, whereas p53-p21 signaling delayed ferroptosis by preserving GSH levels, and thereby had a pro-survival effect 47, 48. induced by GSH depletion Glutathione (-L-glutamyl-L-cysteinyl glycine) is usually a tripeptide made up of a cysteine unit at its core that plays a key role in protecting against lipid peroxidation in ferroptosis by donating an electron to GPX4 41. Intracellular glutathione exists as reduced (GSH) and oxidized glutathione (GSSG), providing the main antioxidant buffer against oxidative stress 44. Studies have exhibited that glutamate-cysteine ligase, the first rate-limiting enzyme in the two-step synthesis of glutathione, could be inhibited by buthionine-(S, R)-sulfoximine (BSO), leading to cell death. DFO and a-tocopherol could reverse this effect, but not the necroptosis inhibitor Necrostain-1 or the apoptosis inhibitor zVAD-fmk 9, 45, 46. Further studies confirmed that erastin induced ferroptosis by GSH down-regulation caused by depletion of intracellular cysteine, whereas p53-p21 signaling delayed ferroptosis by preserving GSH levels, and thereby had GS-626510 a pro-survival effect 47, 48. As a 12 kDa ubiquitous oxidoreductase, thioredoxin plays an essential role in the thioredoxin antioxidant system, composed of NADPH, thioredoxin, and thioredoxin reductase 49. In mammalian cells, thioredoxin and glutathione systems can cross-donate electrons and serve as backup systems for each other 50. Telorack et al. exhibited that this thioredoxin systems could efficiently compensate deficiency in glutathione biosynthesis in keratinocytes to Rabbit Polyclonal to COMT maintain antioxidant capacity 51. Therefore, inhibition of ferroptosis induced by glutathione depletion is an essential mechanism preventing oxidative stress and ferroptotic cell death. Ferroptosis is prevented by GPX4 GPX4, the only member of the GPX protein subfamily (GPX1-8), can reduce phospholipid hydrogen peroxide. It contains an efficient selenocysteine unit that can GS-626510 increase its peroxidase activity GS-626510 52, 53. GPX4 inhibits the formation of Fe2+-dependent ROS by converting lipid hydroperoxides into lipid alcohols. Hence, inhibition of GPX4 leads to an increase of lipid ROS formation and lipid peroxidation, which induces ferroptosis 54. Evidence has revealed that GPX4 knockdown directly inhibits ferroptosis but does not affect other essential mechanisms GS-626510 55. Consistent with this, lack of cysteine diminishes GSH synthesis and reduces GPX4 activity, eventually leading to ferroptosis 56, 57. RSL3, the first reported effective GPX4 inhibitor identified by chemical screening, has been widely used in the experimental induction of ferroptosis, especially in cancer chemotherapy 27. Notably, GPX4 ablation in adult mice resulted in embryonic lethality as evidenced by elevated 4-hydroxylnonenal (4-HNE), reduction in the activity of electron transport chain complexes I and IV, and decreased ATP production in mitochondria that eventually led to neuronal loss, suggesting that GPX4 has an essential role in mitochondrial integrity and neuronal survival 58. Another study confirmed that ferroptosis, rather than apoptosis, is the leading cause of embryonic lethality 45. Additionally, GPX4 is also involved in T cell immunity, as evidenced by GPX4 levels, which were lower in HIV-infected cell populations than in uninfected cells by using 75Se-labeled human Jurkat T cells 59. Another study revealed that GPX4-deficient T cells could rapidly accumulate membrane lipid peroxides accompanied by ferroptosis-mediated cell death rather than necroptosis 60. Since GPX4 can act as an important unfavorable regulatory factor of ferroptosis by scavenging toxic intracellular lipid hydroperoxides, the development of drugs for the regulation of GPX4 is usually of great practical significance. Ferroptosis is usually induced by PUFAs Excessive PUFA consumption, especially red and processed meat, has been associated with nutritional and environmental health hazards 61. High PUFA intake indicates an increased risk of ARDs, including cancers, type 2 diabetes, and CVDs, but the specific molecular mechanism remains unclear 62. Ferroptosis can be driven by excessive peroxidation of PUFAs, characterized by iron-catalyzed excessive peroxidation of PUFA-containing phospholipids 63. Although PUFAs can increase membrane fluidity and have beneficial effects on human health 64, exposure to excess substrates (iron or glutamate) can trigger enzyme-linked reactions by activating enzymes associated with the biosynthesis and.