# Lipid droplets and the regulation of ferroptosis

> **NIH NIH F31** · UNIVERSITY OF CALIFORNIA BERKELEY · 2020 · $40,482

## Abstract

PROJECT SUMMARY
Ferroptosis is a form of regulated cell death that generates reactive oxygen species (ROS) in an iron-
dependent fashion. The most important of the ROS are lipid peroxides, which self-propogate along the plasma
membrane and result in the accumulation of oxidatively damaged lipids. These lipid peroxides lead to a loss of
membrane integrity, leakage of cellular and subcellular content and, ultimately, cell death. The main protective
mechanism against ferroptosis relies on a gluathione-dependent peroxidase (GPX4); this enzyme converts
lipid peroxides to lipid alcohols, thus blocking cell death. Defects in this protective pathway have been
implicated in the etiology of a number of neurodegenerative disorders. Conversely, abrogation of GPX4 has
sensitized drug-resistant cancer cells to chemotherapeutics. Unfortunately, our understanding of the
mechanisms underlying ferroptosis remain limited, but one possibility of ferroptotic regulation may be found in
the enzyme acyl-CoA synthetase long-chain 4 (ACSL4). This enzyme converts free long-chain fatty acids into
fatty acyl-CoA esters, the building blocks of the phospholipids that are fated to propagate ferroptosis.
Knockout of ACSL4 has been shown to stave off ferroptosis in multiple in vivo and in vitro models.
Interestingly, the ACSL4 gene can produce two isoenzymes via alternative splicing; these isoforms differ in
length and in localization, where the long form co-localizes to lipid droplets (LDs) and the short form co-
localizes to the plasma membrane (PM). We hypothesize that this differential localization modulates ferroptotic
sensitivity as the sequestration of lipid peroxides to the LDs may prevent death by ferroptosis. In order to
address this question, cell lines will be created in which endogenous ACSL4 has been eliminated and replaced
with a different expression construct for the two major splice forms of ACSL4. Moreover, these splice forms will
be targeted to various subcellular localizations to investigate the role of these compartments in the execution of
ferroptotic cell death. Additionally, since ACSL4 is integral to lipid metabolism, we will investigate the
composition of fatty acids via Raman spectroscopy and characterize fatty acid flux through lipidomics. This
project addresses an important step in the regulation of ferroptosis, namely how sequestration of damaged
lipids away from critical membrane regions may negatively affect ferroptotic cell death. The enzyme that
governs this sequestration, ACSL4, thus has great pharmacologic potential, not only as a drug target for novel
anti-cancer drugs, but also in age-related neurological diseases.

## Key facts

- **NIH application ID:** 9984152
- **Project number:** 5F31GM134645-02
- **Recipient organization:** UNIVERSITY OF CALIFORNIA BERKELEY
- **Principal Investigator:** Siti Nur Sarah Morris
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $40,482
- **Award type:** 5
- **Project period:** 2019-07-09 → 2021-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9984152

## Citation

> US National Institutes of Health, RePORTER application 9984152, Lipid droplets and the regulation of ferroptosis (5F31GM134645-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9984152. Licensed CC0.

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