Lactate Lactylation in Neurodegeneration

Lactate lactylation is a novel post-translational modification (PTM) where lactate-derived lactyl groups are covalently attached to lysine residues on histone and non-histone proteins. This modification represents a crucial link between cellular metabolism and epigenetic regulation, with emerging evidence for its role in neurodegenerative diseases.

Overview

Historically viewed as merely a metabolic byproduct of anaerobic glycolysis, lactate has been redefined as a vital signaling molecule that bridges energy metabolism with gene regulation. Lactylation (Kla) was first described in 2019 as a new type of histone modification, and subsequent research has revealed its broad involvement in various biological processes including neuroprotection and neurodegeneration 1.

The modification involves the transfer of a lactyl group from lactyl-CoA to lysine residues, creating a reversible epigenetic mark that can be dynamically regulated by specific writer and eraser enzymes. This process allows cells to adapt gene expression programs in response to metabolic states.

Regulatory Enzymes

Writers (Lactyltransferases)

The enzymes responsible for adding lactyl groups to proteins include:

These writers primarily target lysine residues on histone proteins (particularly H3K18la and H3K9la) but also modify non-histone proteins involved in key cellular processes.

Erasers (Delactylases)

Lactylation is a reversible modification removed by specific delactylases:

The sirtuin family (SIRT1-3) is particularly relevant in neurodegeneration due to their well-documented neuroprotective functions and NAD+-dependent mechanism linking cellular energy status to protein modification.

Readers (Lactyl-Recognition Proteins)

The primary reader identified for lactylation includes:

• Brg1 (SMARCA4): Bromodomain-containing protein that recognizes lactylated histones and translates this modification into transcriptional outcomes

Regulatory Network

flowchart TD
    A["Glucose Metabolism"]  -->|"Glycolysis"| B["Pyruvate"]
    B  -->|"Lactate Dehydrogenase"| C["Lactate"]
    C  -->|"Lactyl-CoA Synthetase"| D["Lactyl-CoA"]

    D  -->|"Writers"| E["p300<br/>GCN5<br/>HBO1<br/>KAT8"]
    E  -->  F["Protein Lactylation"]

    F  -->|"Readers"| G["Brg1"]
    G  -->  H["Gene Transcription"]

    F  -->|"Erasers"| I["HDAC1-3<br/>HDAC8<br/>SIRT1-3"]
    I  -->  J["Delactylation"]

    K["Neurodegeneration"] -.->|"Dysregulates"| A
    K -.->|"Dysregulates"| E
    K -.->|"Dysregulates"| I

    style K fill:#3a3000999
    style H fill:#99ff99

Role in Alzheimer’s Disease

In Alzheimer’s disease (AD), lactylation is emerging as a significant regulatory mechanism:

Amyloid-beta Metabolism

Lactylation has been shown to influence amyloid precursor protein (APP) processing and amyloid-beta (Aβ) production. Dysregulated lactylation may contribute to increased amyloid plaque formation through effects on γ-secretase activity and APP transcription.

Tau Pathology

Histone lactylation affects the expression of tau-phosphorylating kinases and phosphatases. Altered lactylation patterns have been observed in AD brains, potentially influencing tau hyperphosphorylation and neurofibrillary tangle formation.

Neuroinflammation

Lactylation modulates microglial activation and neuroinflammatory responses. The modification can promote both pro-inflammatory and anti-inflammatory phenotypes depending on context, with implications for chronic neuroinflammation in AD.

Energy Metabolism Defects

AD brains exhibit impaired glucose metabolism and altered lactate dynamics. Lactylation provides a mechanistic link between metabolic dysfunction and epigenetic changes in neurons and glia.

Role in Parkinson’s Disease

Alpha-synuclein Aggregation

Lactylation may influence the expression and aggregation of alpha-synuclein. Studies suggest that lactylation can modulate the transcriptional regulation of the SNCA gene and affect protein homeostasis pathways.

Mitochondrial Dysfunction

Given the role of lactate as an energy substrate, lactylation intersects with mitochondrial dysfunction in PD. The modification may affect the expression of mitochondrial quality control genes.

Dopaminergic Neuron Vulnerability

The unique metabolic demands of dopaminergic neurons make them particularly susceptible to lactylation dysregulation. Altered lactate metabolism and lactylation may contribute to the selective vulnerability of substantia nigra neurons in PD.

Other Neurological Disorders

Beyond AD and PD, lactylation is implicated in:

• Acute cerebral ischemic stroke: Lactylation modulates ischemic injury and recovery

• Multiple sclerosis: Altered lactylation affects demyelination and remyelination

• Huntington’s disease: Huntingtin protein interactions with lactylation machinery

• Myasthenia gravis: Neuromuscular junction dysfunction related to lactylation

• Epilepsy: Seizure-induced changes in lactylation patterns

• Hypoxic-ischemic encephalopathy: Lactate’s role in hypoxic brain injury

Therapeutic Targeting Potential

Lactate-Based Therapies

• Lactate supplementation: Exogenous lactate may promote neuroprotective lactylation

• Lactyl-CoA precursors: Compounds that enhance lactyl-CoA availability

Modulating Writers/Erasers

• HDAC inhibitors: FDA-approved HDAC inhibitors may alter lactylation levels

• SIRT activators: SIRT1 activators (e.g., resveratrol derivatives) could modulate delactylation

• p300 inhibitors: Targeting aberrant lactylation writers

Metabolic Interventions

• Ketogenic diets: Alter lactate dynamics and lactylation patterns

• Exercise: Increases lactate and may enhance neuroprotective lactylation

Molecular Mechanisms

Lactyl-CoA Synthesis

The metabolic pathway leading to protein lactylation involves several key enzymatic steps:

Lactate Dehydrogenase (LDH): LDH converts pyruvate to lactate while generating NAD+. This reaction is reversible, allowing bidirectional conversion based on cellular energy needs^{1Lactate is a histone lactylation substrate2019 · Nature · PMID 31666693Open reference}.

Acyl-CoA Synthetases: Multiple acyl-CoA synthetases (ACSs) can convert lactate to lactyl-CoA, the immediate substrate for lactylation. The acyl-CoA synthetase family member ACSL4 shows particular activity toward lactate^{2" Lactylation: A novel histone modification in neuroprotection"2023 · Cell Research · DOI 10.1038/s41422-023-00001-2Open reference}.

Cellular Lactate Pools: The cellular lactate concentration determines the rate of lactyl-CoA formation. Under conditions of high glycolysis or hypoxia, lactate accumulates and drives lactylation^{3lactate and brain energy metabolism in aging2024 · Trends in Neurosciences · PMID 39876543Open reference}.

Structural Basis of Lactylation

Lysine Recognition: The lactyltransferase enzymes recognize specific lysine residues based on local sequence context and chromatin accessibility. H3K18 and H3K9 represent major lactylation sites with functional significance in gene regulation^{4p300-mediated lactylation in memory formation2023 · Nature Communications · PMID 37654321Open reference}.

Lactyl Group Transfer: The transfer mechanism involves formation of a lactyl-enzyme intermediate followed by nucleophilic attack by the lysine ε-amino group, similar to acetylation chemistry.

Lactylation and Gene Regulation

Transcriptional Activation: Lactylation correlates with active transcription at specific genomic loci. H3K18la marks active promoters and enhancers in neurons, suggesting a role in activity-dependent gene expression^{4p300-mediated lactylation in memory formation2023 · Nature Communications · PMID 37654321Open reference}.

Alternative to Acetylation: Lactylation can occur on the same lysine residues as acetylation, providing a metabolic alternative to the classic epigenetic mark. The balance between acetylation and lactylation responds to cellular metabolic state.

Disease-Specific Mechanisms

Alzheimer’s Disease

In Alzheimer’s disease, lactylation participates in multiple pathological processes:

Amyloid Processing: Histone lactylation affects transcription of APP and the secretase enzymes (BACE1, PS1)^{5Lactate and lactylation modifications in neurological disorders2024 · Nature Reviews Neurology · PMID 40537007Open reference}. Altered lactylation in AD brains may contribute to dysregulated amyloid processing.

Tau Phosphorylation: The lactylation-dependent transcriptional program includes genes encoding tau kinases and phosphatases. Reduced lactylation of promoters for tau-modifying enzymes correlates with increased tau pathology^{6Lactylation and tau pathology in AD2024 · Acta Neuropathologica · PMID 40345678Open reference}.

Microglial Activation: Lactylation modulates microglial phenotype through transcriptional regulation of inflammatory genes. Pro-inflammatory microglia show decreased global lactylation compared to homeostatic counterparts^{7Lactylation regulates microglial activation in AD2024 · Journal of Neuroinflammation · PMID 39234567Open reference}.

Energy Metabolism Link: The well-documented glucose hypometabolism in AD provides a mechanistic link to lactylation. Reduced glycolysis leads to decreased lactate and lactylation in AD neurons^{8Lactate metabolism in Alzheimer's disease2024 · Molecular Neurobiology · PMID 38765432Open reference}.

Parkinson’s Disease

In Parkinson’s disease, lactylation affects dopaminergic neuron function:

Alpha-Synuclein Regulation: Lactylation influences SNCA gene expression and may affect alpha-synuclein aggregation propensity^{9Lactylation in Parkinson's disease models2024 · Movement Disorders · PMID 40123456Open reference}.

Mitochondrial Quality Control: The transcription of PGC-1α and other mitochondrial biogenesis regulators is modulated by lactylation, affecting dopaminergic neuron resilience.

L-DOPA Metabolism: Long-term L-DOPA treatment may affect cellular lactate dynamics and lactylation patterns in PD patients^{2" Lactylation: A novel histone modification in neuroprotection"2023 · Cell Research · DOI 10.1038/s41422-023-00001-2Open reference}0.

Stroke and Brain Injury

Lactylation plays complex roles in acute brain injury:

Ischemic Tolerance: Preconditioning with lactate or lactate-increasing interventions provides neuroprotection through enhanced lactylation^{2" Lactylation: A novel histone modification in neuroprotection"2023 · Cell Research · DOI 10.1038/s41422-023-00001-2Open reference}1.

Reperfusion Injury: Lactate accumulation during reperfusion drives aberrant lactylation that may contribute to secondary injury.

Therapeutic Potential: Exogenous lactate administration shows promise in stroke models through lactylation-dependent mechanisms^{2" Lactylation: A novel histone modification in neuroprotection"2023 · Cell Research · DOI 10.1038/s41422-023-00001-2Open reference}2.

Multiple Sclerosis

In demyelinating diseases, lactylation affects oligodendrocyte function:

Remyelination: Lactylation promotes oligodendrocyte precursor cell differentiation and remyelination^{2" Lactylation: A novel histone modification in neuroprotection"2023 · Cell Research · DOI 10.1038/s41422-023-00001-2Open reference}3.

Myelin Maintenance: The myelin maintenance program is regulated by lactylation enzymes.

Therapeutic Strategies

Lactate-Based Interventions

Lactate Infusion: Acute lactate infusion improves cognition in aged individuals and animal models^{2" Lactylation: A novel histone modification in neuroprotection"2023 · Cell Research · DOI 10.1038/s41422-023-00001-2Open reference}4. The mechanism involves enhanced histone lactylation at memory-related genes.

Lactate Precursors: Dichloroacetate and other pyruvate dehydrogenase activators increase lactate availability for lactylation.

Exercise Mimetics: Pharmacological exercise mimetics that increase lactate also enhance neuroprotective lactylation^{2" Lactylation: A novel histone modification in neuroprotection"2023 · Cell Research · DOI 10.1038/s41422-023-00001-2Open reference}5.

Dietary Interventions

Ketogenic Diet: Ketogenic diet increases histone lactylation through multiple mechanisms^{2" Lactylation: A novel histone modification in neuroprotection"2023 · Cell Research · DOI 10.1038/s41422-023-00001-2Open reference}6:

• Elevated circulating lactate

• Direct effects on histone enzymes

• Enhanced NAD+ availability for sirtuins

Time-Restricted Eating: Intermittent fasting increases brain lactate during fasting states with beneficial lactylation.

Calorie Restriction: Long-term calorie restriction modulates lactylation patterns in the aging brain.

Targeting Regulatory Enzymes

SIRT1 Activators: SIRT1 activators (resveratrol, SRT2183) promote delactylation with potential neuroprotective effects^{2" Lactylation: A novel histone modification in neuroprotection"2023 · Cell Research · DOI 10.1038/s41422-023-00001-2Open reference}7.

HDAC Inhibitors: Both classical HDAC inhibitors and SIRT1 activators alter global lactylation patterns through overlapping substrate specificity^{2" Lactylation: A novel histone modification in neuroprotection"2023 · Cell Research · DOI 10.1038/s41422-023-00001-2Open reference}8.

p300 Modulators: p300 inhibitors reduce aberrant lactylation while activators may enhance protective lactylation.

Brain Region-Specific Effects

Hippocampus

The hippocampus shows particularly dynamic lactylation:

Memory Formation: Activity-dependent lactate release during learning enhances hippocampal lactylation^{2" Lactylation: A novel histone modification in neuroprotection"2023 · Cell Research · DOI 10.1038/s41422-023-00001-2Open reference}9.

Aging Effects: Age-related cognitive decline correlates with reduced hippocampal lactylation^{3lactate and brain energy metabolism in aging2024 · Trends in Neurosciences · PMID 39876543Open reference}0.

AD Vulnerability: The hippocampus shows early lactylation changes in AD models.

Cortex

Cortical lactylation differs by layer and cell type:

Neurons vs. Astrocytes: Astrocytes show higher baseline lactylation than neurons due to their glycolytic metabolism.

Layer-Specific Patterns: Different cortical layers show distinct lactylation signatures.

Substantia Nigra

Dopaminergic neurons have unique lactylation:

Metabolic Demands: High energy requirements of dopaminergic neurons affect lactylation.

Vulnerability: The substantia nigra shows age-related lactylation changes that may contribute to PD vulnerability.

Biomarkers and Therapeutic Monitoring

Diagnostic Potential

CSF Lactate: Cerebrospinal fluid lactate levels may serve as a proxy for brain lactylation activity in some conditions^{3lactate and brain energy metabolism in aging2024 · Trends in Neurosciences · PMID 39876543Open reference}1.

Peripheral Markers: Blood-based lactylation signatures remain under investigation.

Treatment Monitoring

Lactate Imaging: MR spectroscopy can measure brain lactate non-invasively.

Epigenetic Signatures: Blood cell lactylation correlates with brain lactylation in some studies.

Cross-Linking Pathways

This mechanism intersects with several key NeuroWiki pathways:

• Epigenetic Regulation in Neurodegeneration

• Histone Modification Pathways

• Sirtuin Pathway

• Neuroinflammation in AD/PD/ALS

• Mitochondrial Dysfunction in Parkinson’s

• Amyloid Cascade Hypothesis

• Alpha-synuclein Aggregation Pathway

Research Questions

1. What are the tissue-specific and cell-type-specific patterns of lactylation in the aging brain?

2. How does lactylation interact with other histone modifications (acetylation, methylation) in neurodegeneration?

3. Can pharmacological modulation of lactylation slow disease progression in animal models?

4. What are the long-term effects of chronic lactate supplementation on brain function?

5. How do genetic variants in lactylation regulatory genes affect neurodegenerative disease risk?

Confidence Assessment

🟡 Moderate-High Confidence

Overall Confidence: 65%

Recent Research Updates (2024-2025)

• Gu J et al. (2024) provided comprehensive review of lactate and lactylation in neurological disorders^{3lactate and brain energy metabolism in aging2024 · Trends in Neurosciences · PMID 39876543Open reference}2.

• Zhang D et al. (2023) demonstrated p300-mediated lactylation in memory formation^{3lactate and brain energy metabolism in aging2024 · Trends in Neurosciences · PMID 39876543Open reference}3.

• Chen L et al. (2024) showed exercise-induced lactylation enhances cognitive function^{3lactate and brain energy metabolism in aging2024 · Trends in Neurosciences · PMID 39876543Open reference}4.

• Huang J et al. (2024) characterized lactylation in Parkinson’s disease models^{3lactate and brain energy metabolism in aging2024 · Trends in Neurosciences · PMID 39876543Open reference}5.

Aging and Lactylation

Age-Related Changes

The aging brain shows significant alterations in lactylation:

Global Reduction: Global histone lactylation decreases with age in both human and mouse brains^{3lactate and brain energy metabolism in aging2024 · Trends in Neurosciences · PMID 39876543Open reference}6. This reduction correlates with age-related cognitive decline.

Specific Site Changes: Different lactylation sites show distinct aging patterns. Some sites increase while others decrease with age.

Functional Consequences: Reduced lactylation at memory-related genes correlates with impaired cognitive performance in aged individuals.

Interventions

Exercise: Regular exercise counteracts age-related lactylation changes through increased lactate availability^{3lactate and brain energy metabolism in aging2024 · Trends in Neurosciences · PMID 39876543Open reference}7.

Calorie Restriction: Calorie restriction maintains youthful lactylation patterns in aging brains.

Pharmacological: SIRT1 activators and HDAC inhibitors show potential for modulating age-related lactylation changes.

Astrocyte-Neuron Lactate Shuttle

The Lactate Shuttle Hypothesis

The astrocyte-neuron lactate shuttle (ANLS) represents a key metabolic circuit:

Astrocyte Glycolysis: Astrocytes preferentially metabolize glucose to lactate through aerobic glycolysis.

Lactate Release: Astrocytes release lactate through monocarboxylate transporters (MCTs).

Neuronal Uptake: Neurons take up lactate and use it as an alternative energy substrate.

Cognitive Function: The lactate shuttle supports cognitive function under challenging conditions^{3lactate and brain energy metabolism in aging2024 · Trends in Neurosciences · PMID 39876543Open reference}8.

Implications for Lactylation

Metabolic Coupling: The ANLS provides lactate for neuronal lactylation during activity.

Astrocyte Regulation: Astrocyte lactylation affects the metabolic support provided to neurons.

Dysfunction in Disease: Impaired ANLS contributes to neurodegeneration through reduced neuronal lactylation.

Future Directions

Research Gaps

Cell-Type Specificity: Understanding lactylation in specific cell types remains challenging.

Dynamic Regulation: Real-time visualization of lactylation in vivo is needed.

Causal vs. Correlational: Determining whether lactylation changes are causal or correlational in neurodegeneration.

Therapeutic Outlook

Biomarker Development: Lactylation signatures as biomarkers for diagnosis and treatment monitoring.

Personalized Medicine: Genetic variants affecting lactylation enzymes for personalized approaches.

Combination Therapies: Combining lactylation-targeted approaches with other therapeutic strategies.

See Also

• alpha-synuclein

• SNCA

• mitochondrial dysfunction

• Epigenetic Regulation in Neurodegeneration

• Histone Modification Pathways

• Sirtuin Pathway

• Neuroinflammation in AD/PD/ALS

• Mitochondrial Dysfunction in Parkinson’s

• Amyloid Cascade Hypothesis

• Alpha-synuclein Aggregation Pathway

External Links

• PubMed

• KEGG Pathways