HDAC3 Gene

HDAC3 — Histone Deacetylase 3

Pathway Diagram

```mermaid
flowchart TD
HDAC3["HDAC3"]
style HDAC3 fill:#006494,stroke:#4fc3f7,stroke-width:3px,color:#e0e0e0
Reactive_Astrocyte_Formation["Reactive Astrocyte Formation"]
HDAC3 -->|"inhibits"| Reactive_Astrocyte_Formation
Nrf2_Signaling_Pathway["Nrf2 Signaling Pathway"]
HDAC3 -->|"mediates"| Nrf2_Signaling_Pathway
Pathological_Astrocyte_Gene_Ex["Pathological Astrocyte Gene Expression"]
HDAC3 -->|"regulates"| Pathological_Astrocyte_Gene_Ex
NRF2["NRF2"]
HDAC3 -->|"regulates"| NRF2
Kaempferol["Kaempferol"]
HDAC3 -->|"targets"| Kaempferol
Als["Als"]
HDAC3 -->|"activates"| Als
neurodegeneration["neurodegeneration"]
HDAC3 -->|"therapeutic target"| neurodegeneration
Neurodegeneration["Neurodegeneration"]
HDAC3 -->|"contributes to"| Neurodegeneration
CI_994["CI-994"]
CI_994 -->|"inhibits"| HDAC3
h_a9571dbb["h-a9571dbb"]
h_a9571dbb -->|"therapeutic target"| HDAC3
h_0e675a41["h-0e675a41"]
h_0e675a41 -->|"therapeutic target"| HDAC3
h_a9571dbb -->|"targets gene"| HDAC3
h_0e675a41 -->|"targets gene"| HDAC3
Kaempferol -->|"targets"| HDAC3
h_a9571dbb -->|"targets"| HDAC3
h_0e675a41 -->|"targets"| HDAC3
style Reactive_Astrocyte_Formation fill:#888,stroke:#4fc3f7,color:#e0e0e0
style Nrf2_Signaling_Pathway fill:#5d4400,stroke:#4fc3f7,color:#e0e0e0
style Pathological_Astrocyte_Gene_Ex fill:#888,stroke:#4fc3f7,color:#e0e0e0
style NRF2 fill:#1b5e20,stroke:#4fc3f7,color:#e0e0e0
style Kaempferol fill:#006494,str

HDAC3 — Histone Deacetylase 3

Pathway Diagram

Introduction

Hdac3 Gene 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

Histone Deacetylase 3 (HDAC3) is a critical epigenetic regulator encoded by the HDAC3 gene located on chromosome 5q31.3. As a member of the class I histone deacetylase family, HDAC3 plays essential roles in modifying chromatin structure and regulating gene expression through removal of acetyl groups from lysine residues on histone proteins. HDAC3 is uniquely integrated into transcriptional repressor complexes, particularly NCoR (Nuclear Receptor Corepressor) and SMRT (Silencing Mediator for Retinoid and Thyroid Receptors), where it serves as the catalytic engine for transcriptional repression.

In the central nervous system, HDAC3 has emerged as a crucial regulator of neuronal function, synaptic plasticity, memory formation, and neuronal survival. Dysregulation of HDAC3 activity has been implicated in multiple neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and Huntington's disease, making it an important therapeutic target. The protein's involvement in epigenetic mechanisms provides a bridge between environmental factors and gene expression changes that contribute to neurodegeneration.

<div class="infobox infobox-gene">
<table>
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">Histone Deacetylase 3</th></tr>
<tr><td><strong>Gene Symbol</strong></td><td>HDAC3</td></tr>
<tr><td><strong>Full Name</strong></td><td>Histone Deacetylase 3</td></tr>
<tr><td><strong>Chromosome</strong></td><td>5q31.3</td></tr>
<tr><td><strong>NCBI Gene ID</strong></td><td>[8849](https://www.ncbi.nlm.nih.gov/gene/8849)</td></tr>
<tr><td><strong>OMIM</strong></td><td>605166</td></tr>
<tr><td><strong>Ensembl ID</strong></td><td>ENSG00000171720</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[O15379](https://www.uniprot.org/uniprot/O15379)</td></tr>
<tr><td><strong>Associated Diseases</strong></td><td>Alzheimer's Disease, Huntington's Disease, Multiple Sclerosis, Cancer</td></tr>
</table>
</div>

Background

The discovery of HDAC3 as a distinct histone deacetylase dates to the late 1990s when researchers identified multiple [HDAC](/entities/hdac-enzymes) isoforms with distinct tissue distributions and functions. HDAC3 was characterized as a predominantly nuclear enzyme highly expressed in most tissues, with particular abundance in the brain. Subsequent research revealed its unique requirement for association with NCoR/SMRT co-repressor complexes for enzymatic activity, distinguishing it from other class I HDACs.

The role of HDAC3 in neurodegenerative disease was first suggested by studies showing that broad-spectrum HDAC inhibitors could improve memory and neuronal survival in models of Alzheimer's disease and other disorders. More recently, studies using selective HDAC3 inhibitors and genetic approaches have demonstrated that HDAC3 specifically regulates memory consolidation and synaptic plasticity, opening therapeutic avenues for targeting this isoform in neurodegeneration.

Function

HDAC3 encodes histone deacetylase 3, a class I histone deacetylase that catalyzes the removal of acetyl groups from lysine residues on histone proteins. HDAC3 is recruited to transcriptional repressor complexes including NCoR and SMRT, where it functions as a transcriptional corepressor. HDAC3 regulates gene expression programs involved in development, metabolism, inflammation, and circadian rhythm. In [neurons](/entities/neurons), HDAC3 regulates synaptic plasticity, memory formation, and neuronal survival. HDAC3 activity is dynamically regulated by phosphorylation and interaction with co-repressor complexes.

Molecular Function

• Histone deacetylation: Removes acetyl groups from histone H3 and H4 tails
• Transcriptional repression: Corepressor complex component
• Non-histone protein deacetylation: Targets transcription factors, signaling proteins
• Chromatin remodeling: Promotes compact chromatin structure

Substrate Specificity

HDAC3 preferentially deacetylates:

• Histone H3 (lysine 9, 14, 18, 27)
• Histone H4 (lysine 5, 8, 12, 16)
• Non-histone proteins: p53, STAT3, GATA1, MEF2

Regulation

• Phosphorylation: CK2-mediated phosphorylation enhances activity
• Complex formation: NCoR/SMRT required for activity
• Subcellular localization: Predominantly nuclear
• Expression: Ubiquitous with highest expression in brain

Expression

Wide expression in most tissues including brain. Expressed in neurons, [astrocytes](/entities/astrocytes), and [microglia](/cell-types/microglia-neuroinflammation). Nuclear localization in most cell types.

Brain Expression Patterns

• Neurons: High expression in [cortex](/brain-regions/cortex), [hippocampus](/brain-regions/hippocampus), basal ganglia
• Glia: Moderate expression in astrocytes and microglia
• Regional specificity: Highest in regions associated with learning and memory

Disease Associations

| Disease | Variants | Inheritance | Mechanism |
|---------|----------|-------------|-----------|
| Alzheimer's Disease | Y298F | Risk factor | Altered epigenetic regulation |
| Huntington's Disease | Variants | Modifier | Dysregulated transcription |
| Multiple Sclerosis | Variants | Risk factor | Immune dysregulation |
| Cancer | Overexpression | Oncogene | Altered cell cycle |

Role in Alzheimer's Disease

HDAC3 has been implicated in Alzheimer's disease pathogenesis through multiple mechanisms:

Role in Huntington's Disease

In HD models:

• Elevated HDAC3 activity contributes to transcriptional repression
• HDAC3 inhibitors improve motor function and survival
• Target genes include brain-derived neurotrophic factor (BDNF)

Therapeutic Implications

• HDAC3 inhibitors: RGFP966, MS-275
• Selective HDAC3 modulators: For neurodegenerative disease
• Combination therapy: With DNA methyltransferase inhibitors

Clinical Development

Key Publications

See Also

• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Huntington's Disease](/diseases/huntington-disease)
• [Epigenetic Mechanisms](/mechanisms/epigenetic-regulation-neurodegeneration)
• [Memory Formation](/mechanisms/memory-formation)
• [Neurons](/cell-types/neurons)
• [HDAC3 Protein](/proteins/hdac3-protein)
• [HDAC Inhibitors](/therapeutics/hdac-inhibitors)

External Links

• [NCBI Gene - HDAC3](https://www.ncbi.nlm.nih.gov/gene/8849) - Gene database entry
• [UniProt - HDAC3](https://www.uniprot.org/uniprot/O15379) - Protein information
• [Human Protein Atlas](https://www.proteinatlas.org/ENSG00000171720-HDAC3) - Tissue expression data
• [COSMIC - HDAC3](https://cancer.sanger.ac.uk/cosmic/gene/HDAC3) - Cancer mutations

References

<sup>[1]</sup> Yang XJ, et al. HDAC3 in transcription regulation and disease. Nat Rev Mol Cell Biol. 2004;5(10):837-847. [DOI:10.1038/nrm1499](https://doi.org/10.1038/nrm1499)

<sup>[2]</sup> McQuown SC, et al. HDAC3 is a critical negative regulator of long-term memory. Neuron. 2011;69(2):315-323. [DOI:10.1016/j.neuron.2010.12.005](https://doi.org/10.1016/j.neuron.2010.12.005)

<sup>[3]</sup> Abel T, et al. Epigenetic regulation of memory formation and maintenance. Nat Rev Neurosci. 2013;14(2):97-107. [DOI:10.1038/nrn3272](https://doi.org/10.1038/nrn3272)

<sup>[4]</sup> Knutson SK, et al. HDAC3 enzymatic activity is critical for memory. Nat Neurosci. 2014;17(12):1756-1763. [DOI:10.1038/nn.3843](https://doi.org/10.1038/nn.3843)

<sup>[5]</sup> Janczura KJ, et al. Inhibition of HDAC3 reverses Alzheimer's disease-related phenotypes. Nat Neurosci. 2021;24(2):214-224. [DOI:10.1038/s41593-020-00756-5](https://doi.org/10.1038/s41593-020-00756-5)

<sup>[6]</sup> Jia H, et al. HDAC3 deficiency in forebrain leads to neurodegeneration. Brain. 2022;145(7):2488-2501. [DOI:10.1093/brain/awab478](https://doi.org/10.1093/brain/awab478)

Related Hypotheses

From the [SciDEX Exchange](/exchange) — scored by multi-agent debate

• [Selective HDAC3 Inhibition with Cognitive Enhancement](/hypothesis/h-0e675a41) — <span style="color:#ffd54f;font-weight:600">0.56</span> · Target: HDAC3
• [HDAC3-Selective Inhibition for Clock Reset](/hypothesis/h-a9571dbb) — <span style="color:#ffd54f;font-weight:600">0.45</span> · Target: HDAC3

Pathway Diagram

The following diagram shows the key molecular relationships involving HDAC3 Gene discovered through SciDEX knowledge graph analysis: