Project description:Ferroptosis, an iron-dependent, non-apoptotic cell death program, is involved in a variety of degenerative diseases and represents a targetable vulnerability in certain cancers. The ferroptosis-susceptible cell-state can either preexist in cells arising from certain lineages or be acquired during cell-state transitions. Precisely how ferroptosis susceptibility is dynamically regulated remains poorly understood. Using genome-wide CRISPR/Cas9 suppressor screens, we identify a key role for peroxisome–ether phospholipid genes in driving ferroptosis susceptibility and evasion in ovarian cancer.
Project description:This study was conducted to identify the genes involved in the synthesis of membrane-spanning ether lipids in Thermotoga maritima MSB8.
Project description:This study was conducted to identify the proteins involved in the synthesis of membrane-spanning ether lipids in Thermotoga maritima.
Project description:Vascular disease contributes to neurodegeneration, which is associated with decreased blood pressure in older humans. Plasmalogens, ether phospholipids produced by peroxisomes, are decreased in Alzheimer’s disease, Parkinson’s disease and other neurodegenerative disorders. Here we show that endothelium-derived ether phospholipids affect blood pressure, behavior, and neurodegeneration in mice. In young adult mice, inducible endothelial-specific disruption of PexRAP, a peroxisomal enzyme required for ether lipid synthesis, unexpectedly decreased circulating plasmalogens. PexRAP Endothelial KnockOut (PEKO) mice responded normally to hindlimb ischemia but had lower blood pressure and increased plasma renin activity. In PEKO as compared to control mice, tyrosine hydroxylase was decreased in the locus coeruleus, which maintains blood pressure and arousal. PEKO mice moved less, slept more, and had impaired attention to and recall of environmental events as well as mild spatial memory deficits. In PEKO hippocampus, gliosis was increased and a plasmalogen associated with memory was decreased. Despite lower blood pressure, PEKO mice had generally normal homotopic functional connectivity by optical neuroimaging of the cerebral cortex. Decreased GSK3 phosphorylation, a marker of neurodegeneration, was detected in PEKO cerebral cortex. In a co-culture system, PexRAP knockdown in brain endothelial cells decreased GSK3 phosphorylation in co-cultured astrocytes that was rescued by incubation with the ether lipid alkylglycerol. Our findings suggest that the endothelium is a source of complex lipids that confer neuroprotection in mice.
Project description:We have used in vivo selection to isolate GPX4 knockout 786-O cells that have evaded ferroptosis in vivo in mouse xenograft experiments. RNA-seq and Exome-seq profiling were performed to characterize the mechanisms underlying ferroptosis evasion in these in vivo-derived ferroptosis resistant cells.
Project description:Ferroptosis is a form of regulated cell death driven by lipid peroxidation of polyunsaturated fatty acids (PUFAs). Endogenous PUFAs are nonconjugated PUFAs and their peroxidation proceeds via the hydrogen-atom transfer (HAT) mechanism. We previously reported that lipids with conjugated double bonds undergo lipid peroxidation mostly via a different mechanism, peroxyl radical addition (PRA), and were much more readily oxidizable than nonconjugated ones. In this study, we aim to elucidate the effects of various unsaturated lipids in sensitizing ferroptosis. We found that while some peroxidation-reactive lipids, such as 7-dehydrocholesterol, vitamins D3 and A, and coenzyme Q10, suppress ferroptosis, both nonconjugated and conjugated PUFAs enhanced cell death induced by RSL3, a ferroptosis inducer. Importantly, we showed that conjugated linolenic acid (CLA 18:3) could act as a ferroptosis inducer by itself and conjugated linoleic acid (CLA 18:2) was more potent in sensitizing cells to RSL3-induced cell death than any nonconjugated PUFAs. We next sought to elucidate the mechanism underlying the different ferroptosis-inducing potency of conjugated and nonconjugated PUFAs. Lipidomics revealed that conjugated and nonconjugated PUFAs are incorporated into distinct cellular lipid species. Furthermore, the different peroxidation mechanisms predict the formation of higher levels of reactive electrophilic aldehydes from conjugated PUFAs than nonconjugated PUFAs, which was confirmed by aldehyde-trapping and mass spectrometry. RNA sequencing revealed that protein processing in the endoplasmic reticulum and proteasome are among the most significantly upregulated pathways in cells treated with CLA 18:3, suggesting increased ER stress and activation of unfolded protein response. Significantly, using click chemistry, we observed increased protein adduction by oxidized lipids in cells treated with an alkynylated CLA 18:2 probe. These results suggest that protein damage by lipid electrophiles is a key step in ferroptosis.
Project description:Iron overload, characterized by accumulation of iron in tissues, induces a multiorgan toxicity whose mechanisms are not fully understood. Using cultured cell lines, Caenorhabditis elegans, and mice, we found that ferroptosis occurs in the context of iron-overload-mediated damage. Exogenous oleic acid protected against iron-overload-toxicity in cell culture and Caenorhabditis elegans by suppressing ferroptosis. In mice, oleic acid protected against FAC-induced liver lipid peroxidation and damage. Oleic acid changed the cellular lipid composition, characterized by decreased levels of polyunsaturated fatty acyl phospholipids and decreased levels of ether-linked phospholipids. The protective effect of oleic acid in cells was attenuated by GW6471 (a PPAR- antagonist), as well as in Caenorhabditis elegans lacking the nuclear hormone receptor NHR-49 (a PPAR- functional homologue). These results highlight ferroptosis as a driver of iron-overload-mediated damage, which is inhibited by oleic acid. This monounsaturated fatty acid represents a potential therapeutic approach to mitigating organ damage in iron overload individuals.
Project description:Hemolysis drives susceptibility to lung injury and predicts poor outcomes in diseases, such as malaria and sickle cell disease (SCD). However, the underlying pathological mechanism remains unknown. Here, we report that major facilitator superfamily domain containing 7C (MFSD7C) protects the lung from hemolytic-induced damage by preventing ferroptosis. Mechanistically, MFSD7C deficiency leads to mitochondrial dysfunction and lipid remodeling caused by increased fatty acid uptake and decreased consumption, the excess accumulation of lipids sensitizes cells to peroxidation and ferroptosis. Moreover, systematic delivery of MFSD7C mRNA-loaded nanoparticles to the lungs effectively prevented lung injury in mice with hemolysis. These findings present the detailed link between hemolytic complications and ferroptosis, providing potential therapeutic targets for patients with hemolytic disorders.