Leveraging evolutionary adaptations to uncover mechanisms of oxidative stress resistance

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PROJECT SUMMARY / ABSTRACT Imbalances in reactive oxygen species generation and removal can lead to irreversible damage to macromolecules, such as lipids. The accumulation of oxidatively damage lipids (i.e., lipid peroxides) is a hallmark feature of ferroptosis, an iron-dependent regulated form of cell death. Lipid peroxidation and ferroptosis have been implicated in the etiology of aging, age-related diseases (e.g., neurodegeneration), and other forms of tissue degeneration such as ischemia-reperfusion injury. However, the mechanisms by which cells combat lipid peroxidation and ferroptosis, as well as how these processes can be therapeutically targeted, remain poorly understood. To address this gap in knowledge, our proposed research aims to develop cultured elephant seal cells as a non-traditional comparative model system to identify new mechanisms that suppress oxidative stress and ferroptosis. Elephant seals provide an exceptional model system for questions related to oxidative stress because they have evolved a remarkable resistance to oxidative tissue damage. During dives up to 2-hours, elephant seals undergo progressive and repeated tissue ischemia, but in contrast to the ischemia-reperfusion injury that occurs in humans, elephant seal tissues are protected from damage. Furthermore, our preliminary data demonstrate that cultured elephant seal cells are resistant to a variety of oxidative stressors (e.g., ferroptosis inducers), indicating that elephant seals have evolved cell autonomous mechanisms to suppress oxidative damage and ferroptosis. Elucidating the mechanisms that provide elephant seal cells with this unique ability to prevent oxidative damage provides an extraordinary opportunity to uncover unexpected pathways that will provide insights into aging and diseases associated with oxidative stress and will reveal new potential therapeutic opportunities. Here, we propose to develop genetic editing methods and genome-wide CRISPR-Cas9 libraries to study known lipid peroxidation and ferroptosis in cultured elephant seal and human cells (Aim 1). Furthermore, we will perform genome-wide synthetic lethal screens to systematically uncover the mechanisms of ferroptosis resistance in cultured elephant seal cells (Aim 2). Completion of these studies will provide the first genome-wide CRISPR-Cas9 library for elephant seal cells and will identify novel genetic modifiers of ferroptosis, launching a new model system into the molecular era, potentially yielding insights into the etiology of degenerative diseases, and providing a foundation for the development of novel therapeutic strategies.