# Elucidate the mechanisms of ferroptosis mediated by nonconjugated and conjugated polyunsaturated fatty acids

> **NIH NIH R21** · UNIVERSITY OF WASHINGTON · 2024 · $414,979

## Abstract

Project Summary. Ferroptosis is a regulated form of cell death that is dependent on iron and driven by lipid
peroxidation. Glutathione peroxidase 4 (GPX4) plays a central role in inhibiting ferroptosis as it reduces lipid
peroxides to alcohols, which prevents the initiation of lipid peroxidation via iron-mediated Fenton chemistry.
Oxidizable polyunsaturated fatty acids (PUFAs) have been found to sensitize cells to ferroptosis. Endogenous
PUFAs in the human body only contain nonconjugated double bonds and undergo lipid peroxidation primarily
through the “hydrogen-atom transfer” (HAT) mechanism. On the other hand, we recently discovered that PUFAs
with conjugated double bonds display much higher reactivity toward lipid peroxidation than nonconjugated
PUFAs, and their oxidation proceeds primarily via a “peroxyl radical addition” (PRA) mechanism. Specifically,
conjugated linoleic acid (CLA 18:2) is twice as reactive as nonconjugated linoleic acid (NLA 18:2), while
conjugated linolenic acid (CLA 18:3) is over 8 times more reactive than nonconjugated linolenic acid (NLA 18:3).
CLA 18:2 and CLA 18:3 are found in the diet that includes meat and dairy products from ruminants and some
edible plants. Significantly, it was recently found that CLA 18:3 induces ferroptosis by itself through a mechanism
distinct from canonical ferroptosis inducers, such as GPX4 inhibitors. Furthermore, we found that CLA 18:2 is
much more potent in enhancing ferroptosis in cancer cell lines than any nonconjugated PUFAs. However, the
mechanism of ferroptosis induction or potentiation by CLAs remains to be elucidated. The goal of this project is
to elucidate how the different oxidation mechanisms between NLAs and CLAs lead to their different potency in
inducing ferroptosis. The unique oxidation mechanism of CLAs is expected to lead to the truncation of the fatty
acids and subsequent formation of high levels of aldehydes, which are reactive electrophiles that can form
adducts with nucleophiles, such as proteins, in a biological system. We hypothesize that the PRA peroxidation
mechanism and the resulting high levels of reactive electrophilic products are underlying the mechanism of
ferroptosis induction by conjugated PUFAs. In Aim 1, we will determine the spatial distribution and progression
of lipid peroxidation in cells treated with NLAs or CLAs using stimulated Raman scattering (SRS) microscopy
and lipidomics. In Aim 2, we will reveal the protein targets of the electrophilic products of conjugated PUFAs
using protein pulldown with alkynylated probes and determine the gene targets of these products using RNA
sequencing. This project is significant because it will reveal the detailed steps between lipid peroxidation and the
eventual cell death, including the location and progression of lipid peroxidation and protein and gene targets of
lipid electrophiles, all of which could lead to new ways to modulate ferroptosis for the prevention and treatment
of cancer or degenerative diseases...

## Key facts

- **NIH application ID:** 11036168
- **Project number:** 1R21AT013103-01
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** Dan Fu
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $414,979
- **Award type:** 1
- **Project period:** 2024-09-13 → 2026-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11036168

## Citation

> US National Institutes of Health, RePORTER application 11036168, Elucidate the mechanisms of ferroptosis mediated by nonconjugated and conjugated polyunsaturated fatty acids (1R21AT013103-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/11036168. Licensed CC0.

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