ACSL4 Gene - Acyl-CoA Synthetase Long Chain Family Member 4

Introduction

Pathway Diagram

flowchart TD
    A["ACSL4<br/>Acyl-CoA Synthetase<br/>Long Chain Family 4"]
    B["MIR130B3P<br/>MicroRNA 130b-3p"]
    C["Ferroptosis<br/>Iron-dependent<br/>Cell Death"]
    D["Lipid Peroxidation<br/>Oxidative Damage<br/>to Membrane Lipids"]
    E["Arachidonic Acid<br/>Metabolism"]
    F["Multiple Sclerosis<br/>MS"]
    G["Amyotrophic Lateral<br/>Sclerosis<br/>ALS"]
    H["Alzheimer's Disease<br/>AD"]
    I["Neuroinflammation"]
    J["Oxidative Stress<br/>ROS Generation"]
    K["Membrane<br/>Integrity Loss"]
    L["Neuronal Death"]
    M["Iron Homeostasis<br/>Dysregulation"]
    N["Phospholipid<br/>Biosynthesis"]
    O["Therapeutic<br/>Intervention"]

    B -->|"inhibits"| A
    A -->|"promotes"| C
    A -->|"promotes"| D
    A -->|"regulates"| E
    A -->|"activates"| N
    C -->|"leads_to"| K
    D -->|"causes"| J
    E -->|"contributes_to"| D
    N -->|"maintains"| K
    J -->|"triggers"| C
    M -->|"enhances"| C
    K -->|"results_in"| L
    C -->|"associated_with"| F
    C -->|"associated_with"| G
    A -->|"therapeutic_target"| O
    O -->|"treats"| F
    O -->|"treats"| G
    A -->|"inhibits"| H
    I -->|"promotes"| D

    style A fill:#006494
    style B fill:#4a1a6b
    style C fill:#ef5350
    style D fill:#ef5350
    style J fill:#ef5350
    style L fill:#5d4400
    style F fill:#5d4400
    style G fill:#5d4400
    style H fill:#5d4400
    style O fill:#1b5e20
    style E fill:#4a1a6b
    style N fill:#4a1a6b
    style I fill:#ef5350
    style K fill:#ef5350
    style M fill:#ef5350

Acsl4 Gene Acyl Coa Synthetase Long Chain Family Member 4 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Overview

ACSL4 (Acyl-CoA Synthetase Long Chain Family Member 4) encodes a member of the acyl-CoA synthetase family that catalyzes the conversion of long-chain fatty acids to acyl-CoA esters. ACSL4 is particularly important for ferroptosis sensitivity as it preferentially activates arachidonic acid and adrenic acid, which are substrates for lipid peroxidation during ferroptotic cell death.

Molecular Function

Enzymatic Activity

ACSL4 catalyzes the following reaction:

• Substrate: Long-chain fatty acids (C12-C20)

• ATP-dependent: Uses ATP to form acyl-CoA

• Coenzyme A: Incorporates CoA to form acyl-CoA esters

Substrate Specificity

What distinguishes ACSL4 from other ACSL family members:

1. Arachidonic acid (AA): Preferred substrate (20:4 n-6)

2. Adrenic acid (AdA): Important substrate (22:4 n-6)

3. Less activity: Towards saturated and monounsaturated fatty acids

Expression Pattern

Brain Expression

ACSL4 is expressed in various neural cell types:

• Neurons: High expression in pyramidal neurons

• Astrocytes: Moderate expression

• Microglia: Expression in activated microglia

• Endothelial cells: Blood-brain barrier

Regional Distribution

• Hippocampus: High expression in CA1 region

• Cortex: Moderate to high cortical expression

• Basal Ganglia: Expression in striatal neurons

• Cerebellum: Purkinje cell expression

Disease Associations

Ferroptosis and Neurodegeneration

ACSL4 is a key determinant of ferroptosis sensitivity:

• ACSLA promotes ferroptosis: By producing AA-CoA for lipid peroxidation

• ACSL4 inhibition is protective: Blocks ferroptosis

• Therapeutic targeting: ACSL4 inhibitors being developed

Amyotrophic Lateral Sclerosis (ALS)

• Motor neurons depend on ACSL4/GPX4 balance

• Lipid composition affects ferroptosis sensitivity

• ACSL4 expression may be altered in ALS

Parkinson’s Disease

• Dopaminergic neurons have high ACSL4 expression

• Vulnerability to ferroptosis

• Iron + ACSL4 = enhanced lipid peroxidation

X-linked Intellectual Disability

• ACSL4 mutations cause X-linked ID

• First identified in patients with mild ID and corpus callosum hypoplasia

• Females carriers may have mild cognitive deficits

Therapeutic Targeting

ACSL4 Inhibitors

Therapeutic Implications

• Ferroptosis induction: In cancer therapy

• Ferroptosis inhibition: In neurodegeneration

• Combination therapies: With iron chelators or GPX4 activators

Research Directions

• Develop selective ACSL4 inhibitors

• Understand tissue-specific ACSL4 regulation

• Explore ACSL4 as biomarker

• Gene therapy approaches

Ferroptosis Mechanism and ACSL4’s Central Role

The Ferroptosis Pathway

Ferroptosis is an iron-dependent, non-apoptotic form of cell death characterized by lipid peroxidation^{4*ACSL4 and ferroptosis sensitivity*. Nature Chemical BiologyACSL4 and ferroptosis sensitivity · PMID 32877946Open reference}. Unlike apoptosis or necrosis, ferroptosis is distinct in its morphology and biochemical mechanisms:

Morphological Features

• Preserved plasma membrane integrity until late stages

• No nuclear condensation or DNA fragmentation (unlike apoptosis)

• Reduced mitochondrial size with dense membranes

• cytoplasmic liposome accumulation

Biochemical Requirements

1. Iron availability: Ferrous iron (Fe²⁺) catalyzes lipid peroxidation via Fenton reactions

2. Polyunsaturated fatty acids: PUFAs in membrane phospholipids are peroxidation targets

3. Lipoxygenase activity: 12/15-lipoxygenases generate lipid hydroperoxides

4. Loss of antioxidant defenses: GPX4 inactivation triggers ferroptosis

ACSL4 as a Master Regulator

ACSL4 is essential for ferroptosis execution due to its unique substrate specificity^{4*ACSL4 and ferroptosis sensitivity*. Nature Chemical BiologyACSL4 and ferroptosis sensitivity · PMID 32877946Open reference}:

Arachidonic Acid Metabolism

Arachidonic Acid (20:4 n-6) → ACSL4 → Arachidonoyl-CoA → Phospholipid incorporation
                                                                        ↓
                                                            Lipid peroxidation (when Fe²⁺ present)
                                                                        ↓
                                                                    Ferroptosis

Why ACSL4 is Critical

1. Phospholipid remodeling: ACSL4 incorporates AA and AdA into membrane phospholipids (PE, PC)

2. Peroxidation substrate: These PUFA-containing phospholipids are highly susceptible to peroxidation

3. Iron dependency: Fe²⁺ catalyzes the Fenton reaction with lipid hydroperoxides

4. GPX4 vulnerability: When GPX4 cannot reduce lipid hydroperoxides, cells undergo ferroptosis

GPX4-ACSL4 Axis

The relationship between ACSL4 and GPX4 is central to ferroptosis regulation:

ACSL4 in Neurodegenerative Diseases

Alzheimer’s Disease

ACSL4 is increasingly recognized in AD pathogenesis through multiple mechanisms^{1*ACSL4 in neurodegeneration*. Journal of NeurochemistryACSL4 in neurodegeneration · PMID 32472567Open reference}:

Lipid Metabolism Dysregulation

• Altered brain lipid composition in AD brains

• Increased AA in membrane phospholipids

• Enhanced lipid peroxidation markers (4-HNE, MDA)

• Correlation with disease severity

Ferroptosis in AD

• Evidence of ferroptotic cell death in AD brain

• Iron accumulation in vulnerable regions (hippocampus, entorhinal cortex)

• GPX4 downregulation in AD

• ACSL4 upregulation in early AD (compensatory?)

Therapeutic Implications

Amyotrophic Lateral Sclerosis (ALS)

Motor neurons are particularly vulnerable to ferroptosis due to their high ACSL4 expression^{2*Lipid peroxidation in ALS*. Annals of NeurologyLipid peroxidation in ALS · PMID 28799612Open reference}:

Motor Neuron Vulnerability

• High ACSL4 expression in spinal motor neurons

• Large axonal surface area = high membrane PUFA content

• High iron requirements for mitochondrial function

• Limited antioxidant capacity

Evidence in ALS

• Post-mortem ALS spinal cord shows lipid peroxidation markers

• GPX4 is reduced in ALS models

• ACSL4 expression alterations in some familial ALS

• Ferroptosis inhibitors protect motor neurons in vitro

Parkinson’s Disease

Dopaminergic neurons in the substantia nigra show particular vulnerability^{1*ACSL4 in neurodegeneration*. Journal of NeurochemistryACSL4 in neurodegeneration · PMID 32472567Open reference}:

Why Dopaminergic Neurons are Vulnerable

1. High ACSL4: Constitutive expression in dopaminergic neurons

2. Iron accumulation: Substantia nigra has highest brain iron

3. High PUFA content: Dopamine itself can undergo oxidation

4. Mitochondrial stress: PD-associated mutations affect mitochondria

Iron-ACSL4 Interaction

• Iron promotes lipid peroxidation through Fenton chemistry

• ACSL4 generates more peroxidation-susceptible phospholipids

• Combined effect dramatically increases ferroptosis susceptibility

• Antioxidant systems (GPX4, GSH) decline with age

Ferroptosis vs. Apoptosis in Neurodegeneration

Understanding the interplay between ferroptosis and other cell death pathways is critical:

Key Differences

Cross-talk

• Some apoptosis inducers can trigger ferroptosis

• Caspase inhibition may shift death mode to ferroptosis

• Combined inhibition may provide better neuroprotection

Therapeutic Targeting of ACSL4

Small Molecule Inhibitors

Natural Compounds

• Curcumin: Modulates ACSL4 expression

• Resveratrol: Reduces ACSL4-mediated ferroptosis

• Omega-3 fatty acids: Compete with AA for ACSL4

• Quercetin: Antioxidant that may inhibit ferroptosis

Therapeutic Strategies

Direct ACSL4 Inhibition

• Advantages: Prevents ferroptosis initiation

• Challenges: Potential metabolic side effects

• Delivery: Must cross blood-brain barrier

• Timing: Early intervention likely needed

Upstream Approaches

• Iron chelation: Reduce iron availability

• Lipid modification: Dietary omega-3 supplementation

• GPX4 activation: Enhance antioxidant capacity

• Combination: Multi-target approaches

ACSL4 as a Biomarker

Clinical Potential

ACSL4 and related metabolites show promise as biomarkers:

Challenges

• Tissue specificity (brain vs. peripheral)

• Temporal variation

• Standardization of measurement

• Correlation with clinical outcomes

Genetic Factors

ACSL4 Variants

• Common variants: May influence disease risk

• Rare loss-of-function: Protective against ferroptosis

• Gain-of-function: Increased neurodegeneration risk

• Sex differences: X-linked gene, potential sex-specific effects

Regulation by Non-coding RNAs

• miRNAs: Target ACSL4 mRNA

• lncRNAs: Modulate ACSL4 expression

• circRNAs: Compete for miRNA binding

• Therapeutic potential: RNA-based therapies

Summary

ACSL4 serves as a critical determinant of ferroptosis susceptibility in neurons through its preferential activation of arachidonic acid and adrenic acid. The enzyme’s activity directly influences cellular lipid composition, with PUFA-rich membranes becoming vulnerable to iron-catalyzed lipid peroxidation when antioxidant defenses (particularly GPX4) are compromised.

In neurodegenerative diseases including Alzheimer’s disease, ALS, and Parkinson’s disease, ACSL4-mediated ferroptosis contributes to the selective vulnerability of specific neuronal populations. Dopaminergic neurons, motor neurons, and hippocampal neurons all show high ACSL4 expression combined with iron accumulation and age-related antioxidant decline.

Therapeutic targeting of ACSL4, either directly or through upstream modulators like iron chelation and lipid modification, represents a promising approach to neuroprotection. However, the essential metabolic functions of ACSL4 necessitate careful consideration of potential side effects. Biomarker development for ferroptosis risk stratification and treatment response monitoring will be critical for clinical translation.

Key Publications

Background

The study of Acsl4 Gene Acyl Coa Synthetase Long Chain Family Member 4 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.

Allen Brain Atlas Data

ACSL4 (Acyl-CoA Synthetase Long Chain Family Member 4) expression in the human brain has been characterized through the Allen Brain Atlas:

• Primary Expression: ACSL4 is expressed in neurons and astrocytes, with higher expression in specific neuronal populations

• Regional Distribution: Moderate expression in the cerebral cortex, hippocampus, and basal ganglia

• Cellular Localization: Enriched in neuronal soma and dendrites; also expressed in astrocytes

• Disease Relevance: ACSL4 is critical for ferroptosis susceptibility - the enzyme promotes lipid peroxidation, making neurons with high ACSL4 expression more vulnerable to ferroptotic cell death in AD and ALS

Related Resources

• Allen Brain Atlas Human Brain Atlas

• Allen Brain Atlas Gene Expression

External Links

• NCBI Gene: ACSL4

• UniProt: O60488

• Ensembl: ENSG00000068366

• GeneCards: ACSL4