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Theses Doctoral

Discovery of Novel Ferroptosis Regulators Using Genetic and Lipidomic Analyses

Bezjian, Carla Tara

Ferroptosis is a form of regulated cell death that results in an accumulation of toxic lipid hydroperoxides. It has been implicated in several human disease models, including cancers, organ failure, and neurodegeneration. Identifying novel regulators and biomarkers for ferroptosis can result in identification of disease states where treatment with ferroptotic inducers or inhibitors can result in a positive outcome for a patient. In this thesis, I will describe several methods that were used to identify novel genetic regulators of ferroptosis. A CRISPR-Cas9-mediated, whole-genome loss of function screen identified several gene knockouts that resulted in a protective phenotype against ferroptosis. These genes were found to play a role in antioxidant response, glutathione bioavailability, and/or labile iron homeostasis consistent with the current model of ferroptotic cell death.

Alternatively, a CRISPR-dCas9-mediated whole genome activation screen found Gch1 overexpression to have a potent anti-ferroptotic effect. Gch1 overexpression resulted in an increase to the basal levels of endogenous antioxidants including BH₄ and CoQ₁₀, as well as protection of a specific class of phospholipids containing polyunsaturated fatty acyl (PUFA) chains. This multipronged defense resulted in strong suppression of ferroptosis. Additionally, we were interested in the protection of this unusual class of phospholipids with two PUFA tails, and if their enrichment would result in a change in sensitivity to ferroptosis. We found that the degrees of unsaturation of the acyl chains, as well as differences in head groups of the phospholipids resulted in significant differences in the ability of the phospholipids to induce a strong ferroptotic response. The study of their uptake, subcellular localization, and remodeling pathways can further elucidate biological pathways of ferroptosis.

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More About This Work

Academic Units
Chemistry
Thesis Advisors
Stockwell, Brent R.
Degree
Ph.D., Columbia University
Published Here
October 27, 2021