Induction of Cell Death by Dietary Fatty Acids

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Project Summary/Abstract Regulated cell death is essential for proper development and for tissue maintenance throughout adulthood. A recently described form of regulated cell death, ferroptosis, is associated with iron-dependent accumulation of oxidized lipids in the cell. Ferroptosis is biochemically distinct from apoptosis, the most well-studied form of regulated cell death. Ferroptosis is induced by metabolic imbalances within the cell, rather than by induction of pro-death apoptotic proteins. Using the model nematode Caenorhabditis elegans, we discovered an astonishing reduction in fertility upon dietary ingestion of omega-6 polyunsaturated fatty acids. We found that the omega-6 fats caused death of germ cells, but not somatic cells, throughout development, and this dietary- induced cell death was largely independent of the classical apoptosis pathway. We recently found that germ cell death is modulated by small molecule ferroptosis-specific inhibitors and inducers, as well as by manipulating iron levels in cells, establishing that ferroptosis is the mode of cell death induced by dietary fats in C. elegans. In this application, we propose to examine the intracellular sites of lipid peroxide production in the gonad, and characterize new genetic modulators of dietary-induced cell death to elucidate the ways in which ferroptosis is regulated at the tissue, cellular and molecular levels. Modifiers of ferroptosis will be tested in mammalian cancer cell lines. Furthermore, we will dissect the mechanisms of tissue-specificity of dietary- induced ferroptosis and the roles of mitochondrial lipids and metabolism in modulating ferroptosis. Our proposed research will impact both the developmental biology field and the cell death field by further dissecting the mechanisms involved in the novel phenomenon of diet-induced ferroptosis using a genetically tractable animal model. Our project is innovative and unique, because it examines dietary omega-6 fatty acid- induction of ferroptosis in an animal, and it reveals the vulnerability of germ cells to this type of regulated cell death.