Ferroptosis

Introduction

Ferroptosis is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes^{1ALOX12 is required for p53-mediated tumour suppression through a distinct ferroptosis pathway.2019 · Nat Cell Biol · DOI 10.1038/s41556-019-0305-6 · PMID 30962574Open reference}.

Overview

Ferroptosis is a regulated form of non-apoptotic cell death characterized by iron-dependent lipid peroxidation and distinct from apoptosis, necroptosis, and ^{2Ferroptosis: an iron-dependent form of nonapoptotic cell death. *Cell*. 2012;149(5):1060-1072. DOI2012 · DOI 10.1016/j.cell.2012.03.042Open reference} autophagy-dependent death. First formally described in 2012 by Dixon et al., ferroptosis has rapidly emerged as a critical mechanism of neuronal death in Alzheimer’s disease, ^{3Iron homeostasis and neurodegeneration in the ageing brain: insight into ferroptosis pathways. *Ageing Res Rev*. 2024;104:102575. ScienceDirect2024Open reference} Parkinson’s disease, Huntington’s disease, and ALS, driven by the brain’s unique vulnerability to iron dysregulation and lipid peroxidation^{4Ferroptosis: a regulated cell death nexus linking metabolism, redox biology, and disease. *Cell*. 2017;171(2):273-285. PubMed2017 · PMID 29249655Open reference2Ferroptosis: an iron-dependent form of nonapoptotic cell death. *Cell*. 2012;149(5):1060-1072. DOI2012 · DOI 10.1016/j.cell.2012.03.042Open reference}. ^{57-Dehydrocholesterol is an endogenous suppressor of ferroptosis. *Science*. 2024. DOI2024 · DOI 10.1126/science.adn7030Open reference}

The brain is particularly susceptible to ferroptosis due to its high iron content (the brain contains ~60 mg of iron in the adult), abundance of polyunsaturated fatty acid (PUFA)-rich membranes (comprising >30% of brain lipids), high oxidative metabolism (consuming ~20% of body oxygen), and limited regenerative capacity. Iron accumulation in specific brain regions is now recognized as a hallmark of multiple neurodegenerative diseases, and ferroptosis represents a mechanistic link between metal dyshomeostasis, oxidative stress, and neuronal death^{3Iron homeostasis and neurodegeneration in the ageing brain: insight into ferroptosis pathways. *Ageing Res Rev*. 2024;104:102575. ScienceDirect2024Open reference}. ^{6The role of ferroptosis in neurodegenerative diseases. *Mol Neurobiol*. 2021;58(4):1965-1978. PubMed2021 · PMID 32832141Open reference}

Molecular Mechanism

Core Machinery

Ferroptosis execution requires three converging elements: iron availability, PUFA-containing phospholipids, and failure of antioxidant defense systems. ^{7Iron-associated lipid peroxidation in Alzheimer's Disease is increased in lipid rafts with decreased ferroptosis suppressors, tested by chelation in mice. *Alzheimers Dement*. 2025. DOI2025 · DOI 10.1002/alz.14541Open reference}

Iron-dependent lipid peroxidation cascade: ^{8Trial of deferiprone in Parkinson''s Disease. *N Engl J Med*. 2022;387(22):2045-2055. DOI: 10.1056/NEJMoa22092542022Open reference}

1. Iron uptake: Transferrin receptor 1 (TfR1) imports iron-bound transferrin into cells; iron is released in endosomes by acidification and enters the cytosolic labile iron pool (LIP) via DMT1/NRAMP2

2. Fenton chemistry: Fe²⁺ reacts with H₂O₂ to generate hydroxyl radicals (•OH) via the Fenton reaction: Fe²⁺ + H₂O₂ → Fe³⁺ + •OH + OH⁻

3. Lipid substrate preparation: ACSL4 esterifies PUFAs (arachidonic acid, adrenic acid) into CoA-derivatives; LPCAT3 incorporates these into membrane phospholipids (particularly phosphatidylethanolamine, PE)

4. Lipid radical formation: Lipoxygenases (ALOX15, ALOX12) and/or iron-catalyzed Fenton reactions abstract hydrogen atoms from PUFA-PE, generating lipid radicals (L•)

5. Radical chain propagation: Lipid radicals react with O₂ to form lipid peroxyl radicals (LOO•), which abstract hydrogen from adjacent PUFAs, propagating a self-amplifying chain reaction

6. Membrane disruption: Accumulation of lipid hydroperoxides (LOOH) alters membrane curvature, generates pores, and ultimately destroys membrane integrity — causing cell death

Key Regulatory Nodes

| Protein/System | Role | Effect on Ferroptosis | ^{2Ferroptosis: an iron-dependent form of nonapoptotic cell death. *Cell*. 2012;149(5):1060-1072. DOI2012 · DOI 10.1016/j.cell.2012.03.042Open reference}0 |---------------|------|----------------------| ^{2Ferroptosis: an iron-dependent form of nonapoptotic cell death. *Cell*. 2012;149(5):1060-1072. DOI2012 · DOI 10.1016/j.cell.2012.03.042Open reference}1 | System Xc⁻ (SLC7A11/SLC3A2) | Cystine/glutamate antiporter | Imports cystine for glutathione synthesis; inhibition (by erastin) promotes ferroptosis | ^{2Ferroptosis: an iron-dependent form of nonapoptotic cell death. *Cell*. 2012;149(5):1060-1072. DOI2012 · DOI 10.1016/j.cell.2012.03.042Open reference}2 | GPX4 | Glutathione peroxidase 4 | Reduces lipid hydroperoxides (LOOH) to alcohols (LOH); the central ferroptosis suppressor | ^{2Ferroptosis: an iron-dependent form of nonapoptotic cell death. *Cell*. 2012;149(5):1060-1072. DOI2012 · DOI 10.1016/j.cell.2012.03.042Open reference}3 | FSP1 (AIFM2) | CoQ10-dependent oxidoreductase | GPX4-independent ferroptosis defense; reduces CoQ10 to CoQ10H₂ which traps lipid radicals | ^{2Ferroptosis: an iron-dependent form of nonapoptotic cell death. *Cell*. 2012;149(5):1060-1072. DOI2012 · DOI 10.1016/j.cell.2012.03.042Open reference}4 | DHODH | Dihydroorotate dehydrogenase | Mitochondrial CoQ10 reduction; third anti-ferroptotic pathway | ^{2Ferroptosis: an iron-dependent form of nonapoptotic cell death. *Cell*. 2012;149(5):1060-1072. DOI2012 · DOI 10.1016/j.cell.2012.03.042Open reference}5 | GCH1-BH4 | GTP cyclohydrolase 1 / tetrahydrobiopterin | BH4 acts as radical-trapping antioxidant; fourth independent ferroptosis defense | ^{2Ferroptosis: an iron-dependent form of nonapoptotic cell death. *Cell*. 2012;149(5):1060-1072. DOI2012 · DOI 10.1016/j.cell.2012.03.042Open reference}6 | Ferritin (FTH1/FTL) | Iron storage | Sequesters labile iron in safe ferric form; ferritinophagy (NCOA4-mediated) releases iron | ^{2Ferroptosis: an iron-dependent form of nonapoptotic cell death. *Cell*. 2012;149(5):1060-1072. DOI2012 · DOI 10.1016/j.cell.2012.03.042Open reference}7 | ACSL4 | Acyl-CoA synthetase long-chain 4 | Enriches membranes with PUFA-PE; essential for ferroptosis execution | ^{2Ferroptosis: an iron-dependent form of nonapoptotic cell death. *Cell*. 2012;149(5):1060-1072. DOI2012 · DOI 10.1016/j.cell.2012.03.042Open reference}8 | LPCAT3 | Lysophosphatidylcholine acyltransferase 3 | Inserts PUFAs into phospholipids; promotes ferroptosis sensitivity | | Nrf2 (NFE2L2) | Transcription factor | Master regulator inducing GPX4, SLC7A11, FTH1, HO-1; major ferroptosis suppressor | | TFRC (TfR1) | Transferrin receptor | Iron uptake; high expression sensitizes cells; recently identified as a ferroptosis marker | | 7-DHC | 7-Dehydrocholesterol | Endogenous ferroptosis suppressor identified in 2024; traps lipid radicals |

The System Xc⁻–GSH–GPX4 Axis

This is the canonical ferroptosis defense pathway, and its disruption is the most common trigger for ferroptosis:

1. System Xc⁻ imports extracellular cystine (oxidized cysteine dimer) in exchange for intracellular glutamate export (1:1 antiport)

2. Cystine is reduced to cysteine, the rate-limiting substrate for glutathione (GSH) synthesis (GSH = γ-glutamylcysteinylglycine)

3. GPX4 uses 2 GSH molecules as cofactors to reduce toxic lipid hydroperoxides (LOOH) to non-toxic lipid alcohols (LOH), oxidizing GSH to GSSG

4. Disruption at any step — System Xc⁻ inhibition (erastin, sorafenib), GSH depletion (BSO), or GPX4 inactivation (RSL3, FIN56) — triggers ferroptosis

5. GPX4 is a selenoprotein (contains selenocysteine at its active site), making selenium availability critical for its synthesis and function

Parallel Defense Pathways (GPX4-Independent)

Recent discoveries have revealed that cells possess multiple independent ferroptosis defense systems:

• FSP1-CoQ10 axis: FSP1 (formerly AIFM2) localizes to the plasma membrane, where it uses NAD(P)H to reduce CoQ10 to CoQ10H₂, which acts as a lipid radical-trapping antioxidant. This pathway operates completely independently of GPX4

• DHODH-CoQ10 axis: In mitochondria, DHODH generates CoQ10H₂ during pyrimidine synthesis, protecting mitochondrial membranes from ferroptosis

• GCH1-BH4 pathway: GCH1 is the rate-limiting enzyme for tetrahydrobiopterin (BH4) synthesis; BH4 selectively protects PUFA-containing phospholipids from oxidation

• 7-Dehydrocholesterol (7-DHC): Identified in 2024 as a potent endogenous ferroptosis suppressor; 7-DHC scavenges lipid peroxyl radicals through its conjugated diene system, with the resulting oxysterols being non-toxic^{2Ferroptosis: an iron-dependent form of nonapoptotic cell death. *Cell*. 2012;149(5):1060-1072. DOI2012 · DOI 10.1016/j.cell.2012.03.042Open reference}9

Ferroptosis in Neurodegenerative Diseases

Alzheimer’s Disease

Multiple lines of evidence implicate ferroptosis in AD pathogenesis^{3Iron homeostasis and neurodegeneration in the ageing brain: insight into ferroptosis pathways. *Ageing Res Rev*. 2024;104:102575. ScienceDirect2024Open reference}0^{3Iron homeostasis and neurodegeneration in the ageing brain: insight into ferroptosis pathways. *Ageing Res Rev*. 2024;104:102575. ScienceDirect2024Open reference}1:

Iron accumulation:

• Iron is elevated 2-3× in AD-affected hippocampus, cortex, and basal ganglia relative to age-matched controls

• amyloid-beta plaques concentrate redox-active iron; Aβ peptide binds Fe²⁺/Fe³⁺ at three histidine residues and generates ROS through Fenton chemistry

• Tau(/proteins/tau pathology disrupts iron metabolism; tau]-expressing neurons show increased labile iron and lipid peroxidation. Tau facilitates APP-mediated iron export; loss of functional tau impairs this pathway

• Brain iron levels (measured by QSM MRI) correlate with cognitive decline and accelerate Aβ and tau-mediated neurodegeneration

Lipid peroxidation:

• Elevated 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA) in AD brain tissue, particularly in hippocampus and entorhinal cortex

• Iron-associated lipid peroxidation is specifically increased in lipid rafts in AD, with decreased expression of ferroptosis suppressors GPX4 and FSP1^{3Iron homeostasis and neurodegeneration in the ageing brain: insight into ferroptosis pathways. *Ageing Res Rev*. 2024;104:102575. ScienceDirect2024Open reference}2

• PUFA-rich membranes in AD hippocampus are particularly vulnerable due to high arachidonic acid content

• Isoprostanes (F2-isoprostanes) — non-enzymatic lipid peroxidation products — are elevated in AD CSF and are among the earliest detectable biomarkers

GPX4 dysfunction:

• GPX4 protein expression and activity are reduced in AD hippocampal neurons

• GSH levels decline progressively from MCI to severe AD

• Selenoprotein synthesis (required for GPX4 active site selenocysteine) is impaired in AD brain

• ACSL4 (the enzyme that sensitizes membranes to ferroptosis) is upregulated in AD brain

Parkinson’s Disease

PD has among the strongest evidence for ferroptosis involvement in any neurodegenerative disease:

• substantia nigra iron accumulation: Dopaminergic neurons in the SNpc have intrinsically high iron content due to iron’s role in dopamine synthesis (tyrosine hydroxylase is an iron-dependent enzyme); iron further increases by ~35% in PD

• dopamine-iron interaction: Dopamine auto-oxidation generates reactive semiquinones and aminochrome; these react with iron to generate lipid peroxides through Fenton chemistry. Neuromelanin (which normally sequesters iron) releases iron upon neuronal death, creating a feed-forward loop

• GSH depletion: Among the earliest biochemical changes in PD — reduced GSH by ~40% in SNpc precedes detectable neuronal loss and may represent a prodromal biomarker

• Ferroptosis markers: Elevated 4-HNE, MDA, and 8-oxo-dG in PD substantia nigra; decreased GPX4 activity

• alpha-synuclein: Binds iron via C-terminal metal-binding domain and promotes lipid peroxidation; ferroptosis inhibitors (ferrostatin-1, liproxstatin-1) protect against α-synuclein toxicity in cellular and animal models

• FAIRPARK-II trial paradox: The iron chelator deferiprone (15 mg/kg twice daily) reduced brain iron in early PD patients but unexpectedly worsened motor symptoms over 36 weeks in patients not receiving dopaminergic therapy^{3Iron homeostasis and neurodegeneration in the ageing brain: insight into ferroptosis pathways. *Ageing Res Rev*. 2024;104:102575. ScienceDirect2024Open reference}3. This suggests iron may play dual roles — a critical insight for therapeutic development: (a) iron is needed for normal dopamine synthesis, (b) chelation timing relative to disease stage is critical, and (c) concurrent dopaminergic therapy may be necessary

Huntington’s Disease

• Striatal iron accumulation: Medium spiny neurons show progressively increased iron in HD, detectable by QSM MRI before symptom onset

• Mutant huntingtin/proteins/huntingtin disrupts iron homeostasis through altered transcription of iron regulatory genes (IRP2, ferritin, ferroportin)

• Ultra-high-field 7T MRI studies correlate cerebral iron levels with neuroinflammatory metabolites in HD, suggesting interconnected ferroptosis and neuroinflammation pathways

• Energy deficits from mitochondrial dysfunction increase ferroptosis susceptibility by reducing NADPH needed for GPX4/FSP1 recycling

• GPX4 dysfunction may contribute to selective vulnerability of the striatum

ALS

• Iron accumulation observed in motor neuron spinal cord segments in ALS, particularly in the ventral horn

• GPX4 expression and activity reduced in ALS motor neurons and patient spinal cord tissue

• Ferroptosis markers (4-HNE, iron) elevated in degenerating motor neurons

• Mutant SOD1 promotes iron-dependent oxidative damage by losing its normal antioxidant function and gaining pro-oxidant activity

• May act synergistically with apoptosis and necroptosis to drive motor neuron death

• CuATSM (copper-containing compound) shows anti-ferroptotic properties in ALS models and is in clinical trials

Therapeutic Targeting

Ferroptosis Inhibitors for Neuroprotection

Iron chelators:

Lipophilic radical-trapping antioxidants (RTAs):

• Vitamin E (α-tocopherol): Natural ferroptosis inhibitor; epidemiological evidence of reduced AD risk at high dietary intake; clinical trials (TEAM-AD) showed modest functional benefit in moderate AD

• Ferrostatin-1: Potent synthetic ferroptosis inhibitor; excellent preclinical efficacy in neuronal cultures and brain slices but limited in vivo pharmacokinetics (rapid metabolism)

• Liproxstatin-1: Improved in vivo stability over ferrostatin-1; neuroprotective in GPX4-knockout mice and ischemia models

• 7-Dehydrocholesterol (7-DHC): Endogenous ferroptosis suppressor identified in 2024; potentially targetable by modulating DHCR7 (the enzyme that converts 7-DHC to cholesterol)

• Edaravone: FDA-approved for ALS; free radical scavenger with anti-ferroptotic properties; may partly explain its modest clinical benefit in ALS

• Idebenone: CoQ10 analog approved for Friedreich’s Ataxia; protects against ferroptosis via FSP1-like activity; explored in AD

GPX4 activators and GSH restorers:

• Selenium supplementation: Essential for GPX4 synthesis (selenocysteine at active site); selenium-enriched diets show neuroprotection in AD and PD models; clinical trials ongoing

• N-acetylcysteine (NAC): GSH precursor; restores intracellular GSH levels; clinical trials in multiple neurological conditions (AD, PD, ALS) with mixed results

• Ebselen: Organoselenium compound with GPX4-mimetic activity; Phase III trials completed for various neurological conditions

Nrf2 activators (upstream ferroptosis defense):

• Dimethyl fumarate (DMF): FDA-approved for MS; activates Nrf2, inducing GPX4, SLC7A11, FTH1, and HO-1

• Sulforaphane: Natural Nrf2 activator from cruciferous vegetables; protects against ferroptosis in preclinical models

• Bardoxolone methyl: Potent synthetic Nrf2 activator; renal trials completed; CNS applications being explored

Exercise as Anti-Ferroptosis Therapy

2025 research demonstrates that eight weeks of aerobic exercise significantly activates the System Xc⁻/GPX4 signaling axis in the prefrontal cortex of AD mice, upregulates ferritin light chain (FTL), downregulates 4-HNE, inhibits ferroptosis, and ameliorates cognitive deficits — providing mechanistic evidence for exercise-mediated neuroprotection against ferroptosis^{3Iron homeostasis and neurodegeneration in the ageing brain: insight into ferroptosis pathways. *Ageing Res Rev*. 2024;104:102575. ScienceDirect2024Open reference}5.

Stem Cell-Derived Therapies

Emerging evidence suggests that stem cell derivatives (exosomes, conditioned media, secretome) from mesenchymal stem cells (MSCs) and neural stem cells can inhibit ferroptosis by restoring GPX4 expression, reducing iron overload, and delivering anti-ferroptotic microRNAs — representing a cell-free therapeutic approach^{3Iron homeostasis and neurodegeneration in the ageing brain: insight into ferroptosis pathways. *Ageing Res Rev*. 2024;104:102575. ScienceDirect2024Open reference}6.

Key Therapeutic Challenges

• blood-brain barrier: Limited CNS penetration of many ferroptosis-targeting drugs; nanoparticle and antibody shuttle delivery systems are being developed^{3Iron homeostasis and neurodegeneration in the ageing brain: insight into ferroptosis pathways. *Ageing Res Rev*. 2024;104:102575. ScienceDirect2024Open reference}7

• Iron specificity: Iron chelators (DFO, DFP, DFX) lack tissue and cellular specificity, depleting physiologically essential iron and potentially impairing iron-dependent neurophysiological processes (dopamine synthesis, myelination, mitochondrial respiration)

• Timing paradox: Iron chelation in early PD without dopaminergic support worsened symptoms, suggesting timing relative to disease stage is critical

• Biomarker gap: No ferroptosis-specific biomarkers exist for patient stratification; lipid peroxidation markers (4-HNE, MDA) and iron levels are non-specific

• Pathway redundancy: Blocking ferroptosis may shift cells to apoptosis or necroptosis; multi-pathway targeting may be needed

Detection and Biomarkers

Laboratory Methods

Potential Clinical Biomarkers

• Plasma 4-HNE and MDA: Lipid peroxidation markers; elevated in AD, PD, ALS — but not ferroptosis-specific

• CSF iron and ferritin: Direct measures of CNS iron homeostasis; require lumbar puncture

• Neuroimaging — Quantitative susceptibility mapping (QSM): MRI technique that detects regional iron accumulation in vivo with high sensitivity; iron maps correlate with neurodegeneration severity

• 7T MRI iron mapping: Ultra-high-field MRI enables submillimeter iron mapping; identifies correlations between iron and neuroinflammation in HD

• Isoprostanes (F2-IsoPs): Non-enzymatic lipid peroxidation products in CSF and plasma; among the earliest detectable biomarkers in AD

• Plasma TfR1: Elevated transferrin receptor levels may reflect CNS iron demand; under investigation

Ferroptosis in neuroinflammation

An important emerging concept is the crosstalk between ferroptosis and neuroinflammation:

• **Iron-loaded microglia accumulate iron and are susceptible to ferroptosis; ferroptotic microglia; can co-occur in the same tissue; Bcl-2 family modulates both (anti-apoptotic Bcl-2 proteins can suppress ferroptosis via effects on mitochondrial iron)

• necroptosis: Both produce necrotic morphology; RIPK1/RIPK3/MLKL drive necroptosis while iron drives ferroptosis; some cross-regulation exists via shared lipid peroxidation pathways

• autophagy: Ferritinophagy (NCOA4-mediated autophagic degradation of ferritin) releases sequestered iron into the LIP and promotes ferroptosis; thus excessive autophagy can trigger ferroptosis — a critical regulatory link

• Pyroptosis: Gasdermin-mediated pore formation; distinct mechanism but recent evidence suggests gasdermin D cleavage can sensitize to ferroptosis

• Oxeiptosis: Oxygen radical-induced cell death via KEAP1-PGAM5-AIFM1 axis; may converge with ferroptosis under conditions of severe oxidative stress

See Also

• apoptosis — Caspase-dependent programmed cell death

• necroptosis — RIPK-mediated regulated necrosis

• reactive oxygen species — Free radical biology

• blood-brain barrier — Key obstacle for drug delivery

• microglia — Brain immune cells and iron handling

• Mitochondrial Dysfunction — Energy failure in neurodegeneration

• neuroinflammation — Inflammatory responses amplifying ferroptosis

External Links

• FerrDb V2: Ferroptosis Database

• KEGG: Ferroptosis Pathway

• UniProt: GPX4

Background

The study of Ferroptosis has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

Brain Atlas Resources

• Allen Human Brain Atlas: Ferroptosis expression search

• Allen Mouse Brain Atlas: Ferroptosis search

• Allen Cell Type Atlas: Transcriptomic cell type reference

• BrainSpan Developmental Transcriptome: Ferroptosis developmental expression

Pathway Diagram

The following diagram illustrates key molecular interactions and regulatory relationships for Ferroptosis, derived from the SciDEX knowledge graph.

flowchart TD
    subgraph Inducers["[!] Ferroptosis Inducers"]
        STING_f["STING"]
        SORAFENIB["Sorafenib"]
        FERRITINO["Ferritinophagy"]
        IRON["Iron Overload"]
    end

    subgraph Core["⚙️ Core Pathway"]
        LIPID["Lipid Peroxidation"]
        FERRO["Ferroptosis"]
        ROS_f["ROS Accumulation"]
    end

    subgraph Suppressors["[ok] Ferroptosis Suppressors"]
        GPX4["GPX4"]
        SLC7A11["SLC7A11/xCT"]
        ATG5_f["ATG5"]
        NUC["Nuciferine"]
        SIRT3_f["SIRT3"]
    end

    subgraph Markers["🔬 Associated Markers"]
        TFR1_f["TFR1"]
        BMAL1_f["BMAL1"]
        MIRO1_f["MIRO1"]
        LAMP2_f["LAMP2"]
    end

    IRON -->|"causes"| ROS_f
    FERRITINO -->|"releases iron"| IRON
    STING_f -->|"activates"| FERRO
    SORAFENIB -->|"induces"| FERRO
    ROS_f -->|"drives"| LIPID
    LIPID -->|"executes"| FERRO

    SLC7A11 -.->|"inhibits"| FERRO
    GPX4 -.->|"reduces"| LIPID
    ATG5_f -.->|"protects against"| FERRO
    NUC -.->|"protects against"| FERRO
    SIRT3_f -.->|"inhibits"| FERRO

    TFR1_f -->|"associated"| FERRO
    BMAL1_f -->|"linked to"| FERRO
    MIRO1_f -->|"activates"| FERRO

    style FERRO fill:#FF4500,color:#e0e0e0
    style GPX4 fill:#90EE90
    style SLC7A11 fill:#90EE90
    style LIPID fill:#FFB347
    style IRON fill:#CD853F