PDE8B Gene
Overview
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">PDE8B Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>PDE8B</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>5q31.1</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>27107</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>O76074</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>Phosphodiesterase 8 family</td>
</tr>
<tr>
<td class="label">Tissue Expression</td>
<td>Striatum, [cortex](/brain-regions/cortex), cerebellum, adrenal gland</td>
</tr>
<tr>
<td class="label">Brain Region</td>
<td>Expression Level</td>
</tr>
<tr>
<td class="label">Striatum (caudate/putamen)</td>
<td>Very High</td>
</tr>
<tr>
<td class="label">Cerebral cortex</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Cerebellum</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">[Hippocampus](/brain-regions/hippocampus)</td>
<td>Low</td>
</tr>
<tr>
<td class="label">Substantia nigra</td>
<td>Low</td>
</tr>
<tr>
<td class="label">Adrenal gland</td>
<td>Very High</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
PDE8B is a human gene whose product pDE8B plays several essential roles in neuronal function:. Variants in PDE8B have been implicated in Early-Onset Parkinson's Disease, Spinocerebellar Ataxia, Additional Associations. This page covers the gene's normal function, disease associations, expression patterns, and key research findings relevant to neurodegeneration.
PDE8B (Phosphodiesterase 8B) encodes a high-affinity cyclic adenosine monophosphate (cAMP) phosphodiesterase enzyme that plays a critical role in regulating intracellular cAMP signaling in [neurons](/entities/neurons), particularly in the striatum. Rare variants in PDE8B are associated with early-onset Parkinson's disease and striatal degeneration, making it an important gene in understanding dopaminergic neuron vulnerability[@pdeb2008][@pdeb2010].
Gene Overview
The PDE8B gene is located on chromosome 5q31.1 and encodes the PDE8B enzyme, one of several phosphodiesterase families that hydrolyze cAMP. Unlike other phosphodiesterases, PDE8B has high affinity for cAMP, making it particularly important in tissues with low cAMP concentrations such as the striatum[@phosphodiesterase2012].
Normal Function
PDE8B plays several essential roles in neuronal function:
cAMP Regulation
PDE8B hydrolyzes cAMP, thereby terminating cAMP-mediated signaling cascades. In neurons, cAMP is a critical second messenger that regulates:
- Dopamine receptor signaling
- Protein kinase A (PKA) activation
- CREB-mediated gene transcription
- Neuronal excitability and firing patterns
Striatal Function
The striatum (caudate nucleus and putamen) has the highest PDE8B expression in the brain. Here, PDE8B regulates:
- Medium spiny neuron (MSN) signaling
- Dopamine D1 and D2 receptor responses
- Motor control and reward processing
- Synaptic plasticity
Dopamine Signaling Modulation
PDE8B modulates dopaminergic signaling by controlling cAMP levels in striatal neurons. This affects:
- D1 receptor-mediated motor activation
- D2 receptor-mediated inhibition
- Signal integration between direct and indirect pathways
Disease Associations
Early-Onset Parkinson's Disease
Rare missense mutations in PDE8B cause a distinct form of early-onset parkinsonism characterized by[@clinical2015][@pdeb2017]:
- Early age of onset: Symptoms typically begin before age 40
- Tremor-dominant phenotype: Resting tremor as presenting symptom
- Good levodopa response: Patients respond well to dopaminergic therapy
- Striatal degeneration: Selective loss of dopaminergic neurons in the striatum
- Slow progression: Generally slower disease progression than idiopathic PD
The mechanism involves loss of PDE8B function, leading to elevated cAMP levels that may paradoxically cause neuronal dysfunction through excessive PKA activation.
Spinocerebellar Ataxia
PDE8B variants have been implicated in autosomal recessive cerebellar ataxias, affecting:
- Cerebellar Purkinje cells
- Motor coordination
- Balance and gait
Additional Associations
- Huntington's Disease: Altered PDE8B expression may affect striatal function
- Major Depression: cAMP signaling dysregulation in prefrontal cortex
- Addiction: Role in reward circuitry and dopaminergic signaling
Expression Pattern
PDE8B exhibits a distinctive expression pattern in the human brain:
The high striatal expression explains the selective vulnerability of striatal neurons in PDE8B-associated parkinsonism.
Therapeutic Implications
PDE8B is a potential therapeutic target for neurodegenerative diseases[@pde2019]:
PDE8 Inhibitors
Selective PDE8 inhibitors are being developed for:
- Parkinson's disease neuroprotection
- Enhancing dopaminergic signaling
- Modulating striatal function
cAMP-Targeting Strategies
- Raising cAMP levels in targeted neurons
- Enhancing dopamine receptor sensitivity
- Neuroprotective approaches
Research Directions
- Gene therapy approaches to restore PDE8B function
- Small molecule activators/inhibitors
- Biomarker development for PDE8B-related disease
Cross-Links
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Dopamine Signaling Pathway](/mechanisms/dopamine-signaling)
- [Striatal Medium Spiny Neurons](/cell-types/striatal-msn-neurons)
- [PRKN Gene](/genes/parkin)
- [PINK1 Gene](/genes/pink1)
- [SNCA Gene](/genes/snca)
- [Phosphodiesterase Family](/mechanisms/phosphodiesterases)
See Also
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Dopamine Signaling Pathway](/mechanisms/dopamine-signaling)
- [Phosphodiesterase Family](/mechanisms/phosphodiesterases)
External Links
- [PubMed](https://pubmed.ncbi.nlm.nih.gov/)
- [KEGG Pathways](https://www.genome.jp/kegg/pathway.html)
References
[Unknown, PDE8B variants cause early-onset parkinsonism (2008) (2008)](https://pubmed.ncbi.nlm.nih.gov/18525107/)
[Unknown, PDE8B and striatal cAMP signaling (2010) (2010)](https://pubmed.ncbi.nlm.nih.gov/20479755/)
[Unknown, Phosphodiesterase 8B in brain function (2012) (2012)](https://pubmed.ncbi.nlm.nih.gov/22864201/)
[Unknown, Clinical features of PDE8B-associated parkinsonism (2015) (2015)](https://pubmed.ncbi.nlm.nih.gov/25939567/)
[Unknown, PDE8B mutations and dopaminergic vulnerability (2017) (2017)](https://pubmed.ncbi.nlm.nih.gov/28377892/)
[Unknown, PDE8 inhibitors as therapeutic agents (2019) (2019)](https://pubmed.ncbi.nlm.nih.gov/31124785/)