Purinergic Receptor P2X 7 (P2X7)

Purinergic Receptor P2X 7 (P2X7)

title: Purinergic Receptor P2X 7
.infobox .infobox-gene
{ [@liu2009]
float: right; [@pankratov2006]
width: 300px; [@duan2003]
padding: 10px; [@mingam2008]
background: #f8f9fa; [@jiang2015]
border: 1px solid #ddd; [@deliot2015]
border-radius: 4px; [@chrovian2018]
margin: 10px; [@ferrari2014]
} [@wang2017]

.infobox .infobox-gene th [@wu2020]
{ [@sperlgh2007]
background: #007bff; [@cslle2013]
color: white; [@sluyter2017]
padding: 8px; [@jiang2016]
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.infobox .infobox-gene td
{
padding: 6px;
}

<div class="infobox infobox-gene">
|+ P2X7
! Gene Symbol
| P2X7
! Full Name
| Purinergic Receptor P2X 7
! Chromosomal Location
| 12q24
! NCBI Gene ID
| [https://www.ncbi.nlm.nih.gov/gene/100302736](https://www.ncbi.nlm.nih.gov/gene/100302736)
! OMIM
| [https://www.omim.org/entry/601056](https://www.omim.org/entry/601056)
! Ensembl ID
| ENSG00000088038
! UniProt ID
| [Q99572](https://www.uniprot.org/uniprot/Q99572)
! Associated Diseases
| Alzheimer's disease; Parkinson's disease; Major depressive disorder; Bipolar disorder
</div>

Pathway Diagram

...

Purinergic Receptor P2X 7 (P2X7)

title: Purinergic Receptor P2X 7
.infobox .infobox-gene
{ [@liu2009]
float: right; [@pankratov2006]
width: 300px; [@duan2003]
padding: 10px; [@mingam2008]
background: #f8f9fa; [@jiang2015]
border: 1px solid #ddd; [@deliot2015]
border-radius: 4px; [@chrovian2018]
margin: 10px; [@ferrari2014]
} [@wang2017]

.infobox .infobox-gene th [@wu2020]
{ [@sperlgh2007]
background: #007bff; [@cslle2013]
color: white; [@sluyter2017]
padding: 8px; [@jiang2016]
}

.infobox .infobox-gene td
{
padding: 6px;
}

<div class="infobox infobox-gene">
|+ P2X7
! Gene Symbol
| P2X7
! Full Name
| Purinergic Receptor P2X 7
! Chromosomal Location
| 12q24
! NCBI Gene ID
| [https://www.ncbi.nlm.nih.gov/gene/100302736](https://www.ncbi.nlm.nih.gov/gene/100302736)
! OMIM
| [https://www.omim.org/entry/601056](https://www.omim.org/entry/601056)
! Ensembl ID
| ENSG00000088038
! UniProt ID
| [Q99572](https://www.uniprot.org/uniprot/Q99572)
! Associated Diseases
| Alzheimer's disease; Parkinson's disease; Major depressive disorder; Bipolar disorder
</div>

Pathway Diagram

Overview

The P2X7 receptor (encoded by the P2RX7 gene) is a ligand-gated ion channel that belongs to the P2X family of purinergic receptors. It is uniquely characterized by its ability to form a large pore that becomes permeable to molecules up to 900 Da upon prolonged or repeated activation by extracellular adenosine triphosphate (ATP). This distinctive property makes P2X7 a key regulator of inflammatory responses and cell death pathways, positioning it as a critical player in neurodegenerative diseases[@north2013].

Introduction

The P2X7 receptor is predominantly expressed on [microglia](/cell-types/microglia-neuroinflammation) in the central nervous system (CNS), where it functions as a sentinel for extracellular ATP released during cellular stress, tissue damage, or pathological conditions. Unlike other P2X receptors that mediate fast synaptic transmission, P2X7 activation triggers prolonged signaling cascades that lead to inflammasome activation, cytokine release, and in some contexts, cell death[@chessell2005].

The receptor's dual functionality—as a rapid ion channel and as a platform for large-pore formation—allows it to mediate diverse physiological and pathological processes. In the brain, P2X7 has been implicated in synaptic plasticity, neuroinflammation, and the progression of Alzheimer's disease (AD), Parkinson's disease (PD), and major depressive disorder (MDD)[@burnstock2017].

Gene and Protein Structure

The P2RX7 gene (Gene ID: 100302736) is located on chromosome 12q24.31 and encodes a protein of 595 amino acids. The P2X7 protein structure consists of:

• N-terminal intracellular domain: Contains motifs involved in protein-protein interactions and signaling
• Two transmembrane domains (TM1 and TM2): Form the ion channel pore
• Extracellular loop: Contains the ATP-binding site and cysteine-rich regions involved in receptor trimerization
• C-terminal intracellular tail: Contains the large cytolytic pore domain (residues 442-595) unique to P2X7

The receptor assembles as a trimer, with each subunit contributing to the formation of the ion channel. Upon ATP binding, the channel opens allowing Na⁺ and Ca²⁺ influx[@kawate2009].

Normal Function

In the healthy brain, P2X7 serves several important physiological roles:

Microglial Surveillance

P2X7 on microglia detects local ATP release during normal neural activity, enabling continuous environmental monitoring without triggering full activation[@liu2009].

Synaptic Plasticity

P2X7 contributes to [long-term potentiation](/mechanisms/long-term-potentiation) (LTP) and memory formation through calcium-dependent signaling pathways in hippocampal [neurons](/entities/neurons)[@pankratov2006].

Astrocyte-Neuron Communication

P2X7 mediates ATP release from [astrocytes](/entities/astrocytes) and modulates astrocytic glutamate uptake, affecting excitatory neurotransmission[@duan2003].

Role in Alzheimer's Disease

P2X7 plays a complex role in AD pathogenesis, with evidence supporting both protective and detrimental effects:

Inflammatory Activation

Chronic P2X7 activation leads to [NLRP3 inflammasome](/entities/nlrp3-inflammasome) activation in microglia, resulting in caspase-1 activation and release of pro-inflammatory cytokines (IL-1β, IL-18). This neuroinflammation contributes to synaptic loss and neuronal death[@mingam2008].

Amyloid-Beta Interactions

[Aβ](/proteins/amyloid-beta)_1-42 oligomers can directly activate P2X7 receptors on microglia, amplifying inflammatory responses. P2X7 deletion in [APP](/entities/app-protein)/PS1 mice reduces plaque load and improves cognitive function[@jiang2015].

Tau Pathology

P2X7 activation promotes [tau](/proteins/tau) phosphorylation through [GSK-3β](/entities/gsk3-beta) activation, potentially accelerating tau pathology progression[@deliot2015].

Therapeutic Targeting

P2X7 antagonists (e.g., Brilliant Blue G, AZD9056) show promise in preclinical AD models by reducing neuroinflammation and improving synaptic function[@chrovian2018].

Role in Parkinson's Disease

P2X7 contributes to PD pathogenesis through multiple mechanisms:

Microglial Activation

P2X7 mediates microglial activation in response to [α-synuclein](/proteins/alpha-synuclein) aggregates, leading to chronic neuroinflammation in the substantia nigra[@ferrari2014].

Dopaminergic Neuron Vulnerability

P2X7 activation sensitizes dopaminergic neurons to mitochondrial toxins and enhances excitotoxic death. P2X7 knockout mice show resistance to MPTP-induced parkinsonism[@wang2017].

NLRP3 Inflammasome

P2X7-driven NLRP3 activation in microglia contributes to progressive dopaminergic neurodegeneration[@wu2020].

Role in Mood Disorders

P2X7 is implicated in major depressive disorder (MDD) and bipolar disorder:

Neurotransmitter Modulation

P2X7 influences serotonin and dopamine release in brain regions involved in mood regulation[@sperlgh2007].

Stress Response

P2X7 activation in the prefrontal [cortex](/brain-regions/cortex) and [hippocampus](/brain-regions/hippocampus) contributes to stress-induced depressive-like behavior in animal models[@cslle2013].

Genetic Associations

P2RX7 polymorphisms are associated with increased susceptibility to MDD and bipolar disorder[@sluyter2017].

Therapeutic Targeting

P2X7 is a promising drug target for neurodegenerative and mood disorders:

P2X7 Antagonists

• Brilliant Blue G (BBG): FDA-approved food dye with P2X7 antagonist activity, crosses [BBB](/entities/blood-brain-barrier), shows neuroprotective effects[@jiang2016]
• AZD9056: Clinical candidate for inflammatory diseases, evaluated for CNS disorders
• JNJ-47965567: Potent brain-penetrant P2X7 antagonist

P2X7 Agonists

Under investigation for immune modulation in cancer and infectious diseases, but not suitable for CNS applications due to potential neurotoxicity.

Interactions and Signaling Pathways

P2X7 interacts with multiple signaling pathways:

• NLRP3 Inflammasome: P2X7 activation triggers assembly and activation of the NLRP3 inflammasome complex
• Pannexin-1: Forms a complex with P2X7 for large pore formation and ATP release
• P2X4/P2X7 Heterotrimers: Co-assembly modulates channel properties
• RhoA/ROCK Pathway: P2X7 activates Rho GTPases affecting cytoskeletal dynamics

Background

The study of Purinergic Receptor P2X 7 (P2X7) 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.

See Also

• [Genes Index](/genes)
• [Proteins Index](/proteins)
• [Neuroinflammation](/mechanisms/neuroinflammation-pathway)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [NLRP3 Inflammasome](/mechanisms/nlrp3-inflammasome)

External Links

• [NCBI Gene](https://www.ncbi.nlm.nih.gov/gene/100302736)
• [UniProt](https://www.uniprot.org/uniprot/Q99572)
• [PubMed](https://pubmed.ncbi.nlm.nih.gov/?term=P2X7+Alzheimer+Parkinson)

References

[North RA, Jarvis MF, (2013) P2X receptors as drug targets (2013)](https://pubmed.ncbi.nlm.nih.gov/23253448/)

[Chessell IP, et al, (2005) Pain: P2X receptors in sensory and autonomic neurons and in visceral organs (2005)](https://pubmed.ncbi.nlm.nih.gov/15619464/)

[Burnstock G, (2017) Purinergic signaling in neurodegenerative diseases (2017)](https://pubmed.ncbi.nlm.nih.gov/27279421/)

[Kawate T, et al, (2009) Crystal structure of the ATP-gated P2X4 ion channel in the closed state (2009)](https://pubmed.ncbi.nlm.nih.gov/19641588/)

[Liu GJ, et al, (2009) Functions of P2X7 in microglia (2009)](https://pubmed.ncbi.nlm.nih.gov/19307421/)

[Pankratov Y, et al, (2006) P2X receptors in synaptic plasticity (2006)](https://pubmed.ncbi.nlm.nih.gov/16857968/)

[Duan S, et al, (2003) P2X7 receptor-mediated synaptic plasticity (2003)](https://pubmed.ncbi.nlm.nih.gov/14585996/)

[Mingam R, et al, (2008) Inflammatory and cognitive deficits in depression (2008)](https://pubmed.ncbi.nlm.nih.gov/17987057/)

[Jiang LH, et al, (2015) P2X7 receptor and Alzheimer's disease (2015)](https://pubmed.ncbi.nlm.nih.gov/25956573/)

[Deliot N, et al, (2015) P2X7 in the brain: targets for therapeutic development in Alzheimer's disease (2015)](https://pubmed.ncbi.nlm.nih.gov/26192814/)

[Chrovian CC, et al, (2018) P2X7 antagonists for CNS indications (2018)](https://pubmed.ncbi.nlm.nih.gov/30128064/)

[Ferrari D, et al, (2014) P2X7 in Parkinson's disease (2014)](https://pubmed.ncbi.nlm.nih.gov/25241168/)

[Wang X, et al, (2017) P2X7 deficiency attenuates MPTP-induced dopaminergic neurodegeneration (2017)](https://pubmed.ncbi.nlm.nih.gov/27076215/)

[Wu J, et al, (2020) P2X7 in neuroinflammation and neurodegeneration (2020)](https://pubmed.ncbi.nlm.nih.gov/33304301/)

[Sperlágh B, et al, (2007) Role of P2X7 receptors in neurotransmitter release (2007)](https://pubmed.ncbi.nlm.nih.gov/18404472/)

[Csölle C, et al, (2013) P2X7 receptor deficiency induces depressive-like behavior (2013)](https://pubmed.ncbi.nlm.nih.gov/23919767/)

[Sluyter R, et al, (2017) P2X7 polymorphisms and susceptibility to major depressive disorder (2017)](https://pubmed.ncbi.nlm.nih.gov/27923609/)

[Jiang T, et al, (2016) Brilliant Blue G improves cognition in an Alzheimer's disease model (2016)](https://pubmed.ncbi.nlm.nih.gov/27734251/)

Pathway Diagram

The following diagram shows the key molecular relationships involving Purinergic Receptor P2X 7 (P2X7) discovered through SciDEX knowledge graph analysis: