CXCR1 (C-X-C Motif Chemokine Receptor 1)
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">CXCR1 Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>CXCR1</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>C-X-C Motif Chemokine Receptor 1</td>
</tr>
<tr>
<td class="label">Aliases</td>
<td>IL8RA, IL-8R1, CD128, CD181</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>2q35</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>[2915](https://www.ncbi.nlm.nih.gov/gene/2915)</td>
</tr>
<tr>
<td class="label">OMIM</td>
<td>[146929](https://www.omim.org/entry/146929)</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>[ENSG00000163464](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00163464)</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>[P41597](https://www.uniprot.org/uniprot/P41597)</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>350 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~40 kDa</td>
</tr>
<tr>
<td class="label">Ligand</td>
<td>Chemokine Family</td>
</tr>
<tr>
<td class="label">CXCL8 (IL-8)</td>
<td>CXC family</td>
</tr>
<tr>
<td class="label">CXCL6 (GCP-2)</td>
<td>CXC family</td>
</tr>
<tr>
<td class="label">CXCL1 (GRO-alpha)</td>
<td>CXC family</td>
</tr>
<tr>
<td class="label">CXCL7 (NAP-2)</td>
<td>CXC family</td>
</tr>
<tr>
<td class="label">Cell Type</td>
<td>Expression Level</td>
</tr>
<tr>
<td class="label">Neutrophils</td>
<td>Highest</td>
</tr>
<tr>
<td class="label">Monocytes/Macrophages</td>
<td>High</td>
</tr>
<tr>
<td class="label">Microglia</td>
<td>Moderate-high</td>
</tr>
<tr>
<td class="label">T Cells</td>
<td>Low-moderate</td>
</tr>
<tr>
<td class="label">NK Cells</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Disease State</td>
<td>CXCR1 Expression</td>
</tr>
<tr>
<td class="label">Alzheimer's Disease</td>
<td>Increased</td>
</tr>
<tr>
<td class="label">Parkinson's Disease</td>
<td>Elevated</td>
</tr>
<tr>
<td class="label">Multiple Sclerosis</td>
<td>Upregulated</td>
</tr>
<tr>
<td class="label">Stroke/Ischemia</td>
<td>Rapidly increased</td>
</tr>
<tr>
<td class="label">ALS</td>
<td>Elevated</td>
</tr>
<tr>
<td class="label">Compound</td>
<td>Target</td>
</tr>
<tr>
<td class="label">Reparixin</td>
<td>CXCR1/2</td>
</tr>
<tr>
<td class="label">Danirixin</td>
<td>CXCR2</td>
</tr>
<tr>
<td class="label">SX-517</td>
<td>CXCR1</td>
</tr>
<tr>
<td class="label">Lidocaine derivatives</td>
<td>CXCR1/2</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/alzheimer" style="color:#ef9a9a">ALZHEIMER</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/amyotrophic-lateral-sclerosis" style="color:#ef9a9a">Amyotrophic Lateral Sclerosis</a>, <a href="/wiki/epilepsy" style="color:#ef9a9a">Epilepsy</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">59 edges</a></td>
</tr>
</table>
Overview
CXCR1 (C-X-C Motif Chemokine Receptor 1), also known as IL-8RA (Interleukin-8 Receptor Alpha), is a G protein-coupled receptor (GPCR) that specifically binds interleukin-8 (IL-8/CXCL8) and granulocyte colony-stimulating factor (G-CSF)[@liu2019]. Originally characterized for its role in neutrophil recruitment and activation during acute inflammation, CXCR1 is now recognized as a significant contributor to chronic neuroinflammatory processes in neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and multiple sclerosis[@bhatia2005].
In the central nervous system (CNS), CXCR1 is expressed on microglia, astrocytes, and neurons, where its activation by IL-8 (produced in response to pathological stimuli) triggers pro-inflammatory signaling cascades that contribute to neuronal dysfunction and death[@rivest2009].
Molecular Function
Ligand Binding
CXCR1 is a high-affinity receptor for:
Signal Transduction Pathways
Upon IL-8 binding, CXCR1 activates multiple intracellular signaling cascades:
Mermaid diagram (expand to render)
Key Signaling Pathways
PI3K/Akt: Cell survival, migration, metabolic regulation
MAPK/ERK: Proliferation, cytokine production, cell differentiation
PLC/IP3: Calcium mobilization, granule release
JAK/STAT: Gene transcription, inflammatory responseReceptor Regulation
- Desensitization: GRK-mediated phosphorylation leads to β-arrestin recruitment
- Internalization: Receptor internalization via clathrin-coated pits
- Recycling: Receptor returns to cell surface or is degraded
Expression Pattern
Immune Cell Expression
CNS Expression
Microglia:
- Resting microglia: Low CXCR1 expression
- Activated microglia: Upregulated CXCR1
- Proximity to amyloid plaques: Elevated expression
Astrocytes:
- Reactive astrocytes: Increased CXCR1
- Inflammatory conditions: Enhanced signaling
Neurons:
- Low baseline expression
- Upregulation in pathological states
- May contribute to excitotoxicity
Expression in Disease
Role in Neurodegeneration
Alzheimer's Disease
CXCR1 plays a significant role in AD pathogenesis:
Microglial Activation[@swardfager2010]:
- IL-8 levels are elevated in AD brains and cerebrospinal fluid
- CXCR1+ microglia surround amyloid plaques
- Activation leads to pro-inflammatory cytokine release
- Sustained inflammation contributes to neuronal dysfunction
Neuroinflammation Cascade:
Amyloid-beta accumulation → IL-8 production by astrocytes/microglia
IL-8 binding to CXCR1 on microglia → activation
Pro-inflammatory cytokine release (TNF-α, IL-1β, IL-6)
Chronic neuroinflammation → synaptic loss, neuronal deathResearch Findings[@bhatia2005]:
- CXCR1 expression colocalizes with amyloid plaques
- IL-8/CXCR1 axis amplifies neuroinflammation
- Correlation between CXCR1 and disease severity
Parkinson's Disease
In PD, CXCR1 contributes to:
Substantia Nigra Inflammation[@zhao2018]:
- Elevated IL-8 in PD substantia nigra
- CXCR1 activation on microglia promotes M1 phenotype
- Inflammatory mediators contribute to dopaminergic neuron death
- Neuroinflammation exacerbates alpha-synuclein pathology
Mechanistic Pathways:
- CXCR1 signaling → oxidative stress
- Cytokine release → mitochondrial dysfunction
- Chronic activation → progressive neurodegeneration
Multiple Sclerosis
- Demyelination: CXCR1+ immune cells contribute to myelin damage
- Lesion Formation: Active MS lesions show elevated CXCR1
- Blood-Brain Barrier Disruption: CXCR1 mediates immune cell trafficking
Amyotrophic Lateral Sclerosis
- Motor Neuron Inflammation: CXCR1 on activated microglia
- Disease Progression: Inflammatory signaling contributes to motor neuron loss
- Therapeutic Target: CXCR1 antagonists under investigation
Stroke and Ischemia
- Post-Ischemic Inflammation: Rapid IL-8 elevation
- Neutrophil Recruitment: CXCR1 mediates post-injury inflammation
- Secondary Damage: Inflammatory cascade exacerbates injury
Therapeutic Implications
CXCR1/2 Antagonists
Several small molecule antagonists have been developed:
Clinical Applications
- Neuroinflammation Modulation: Reduce chronic inflammation
- Microglial Activation: Shift from M1 to M2 phenotype
- Neuroprotection: Prevent inflammatory neuron loss
Challenges
- Receptor Redundancy: Multiple chemokines can signal through CXCR1/2
- Acute vs Chronic: Different effects in acute vs chronic inflammation
- BBB Penetration: Drug delivery to CNS is challenging
Therapeutic Strategies
Small Molecule Inhibitors: Systemic administration
Monoclonal Antibodies: Target circulating IL-8 or CXCR1
ASO Therapy: Reduce IL-8 expression
Gene Therapy: Modulate receptor expressionSignal Transduction in Neurodegeneration
Mermaid diagram (expand to render)
Clinical Significance
Biomarkers
- Serum IL-8: Elevated in AD and PD
- CSF IL-8: Correlates with disease progression
- CXCR1 Expression: On circulating immune cells
Diagnostic Applications
- Imaging: PET ligands for CXCR1 under development
- Expression Analysis: CXCR1 on peripheral monocytes
- Disease Monitoring: IL-8 levels as progression marker
Research Applications
- In Vitro Models: Primary microglia culture
- Animal Models: Transgenic mice, toxin models
- Clinical Trials: CXCR1/2 antagonists in neurodegenerative disease
Key Publications
[Liu et al., CXCR1/2 in neuroinflammation and neurodegeneration (2019)](https://pubmed.ncbi.nlm.nih.gov/31127022/)
[Bhatia et al., IL-8 and CXCR1 in AD (2005)](https://pubmed.ncbi.nlm.nih.gov/15893604/)
[Glass et al., Inflammation in neurodegeneration (2006)](https://pubmed.ncbi.nlm.nih.gov/16439142/)
[Rivest et al., IL-8 signaling in neuroinflammation (2009)](https://pubmed.ncbi.nlm.nih.gov/19818653/)
[Horuk et al., IL-8 receptor molecular characterization (1994)](https://pubmed.ncbi.nlm.nih.gov/7964247/)
[Wood et al., Chemokine receptors on microglia (2006)](https://pubmed.ncbi.nlm.nih.gov/16574082/)
[Galimberti et al., IL-1beta and IL-1RA in AD (2005)](https://pubmed.ncbi.nlm.nih.gov/16006667/)
[Zhao et al., CXCR1/2 in PD and neuroinflammation (2018)](https://pubmed.ncbi.nlm.nih.gov/29753917/)
[Reaux-Le Goazigo et al., Chemokines in brain (2012)](https://pubmed.ncbi.nlm.nih.gov/23316146/)
[Swardfager et al., Meta-analysis of cytokines in AD (2010)](https://pubmed.ncbi.nlm.nih.gov/20692634/)
[Lucin & Wyss-Coray, CX3CL1-CX3CR1 in AD (2010)](https://pubmed.ncbi.nlm.nih.gov/20094918/)
[Cunningham et al., Systemic inflammation in AD progression (2013)](https://pubmed.ncbi.nlm.nih.gov/23831254/)
[White et al., Chemokine signaling in neuropathic pain (2011)](https://pubmed.ncbi.nlm.nih.gov/21306667/)
[Tripathy et al., CXCR1/2 antagonists in neuroinflammation (2018)](https://pubmed.ncbi.nlm.nih.gov/29653269/)External Resources
- [NCBI Gene - CXCR1](https://www.ncbi.nlm.nih.gov/gene/2915)
- [UniProt - P41597](https://www.uniprot.org/uniprot/P41597)
- [Ensembl - CXCR1](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00163464)
- [OMIM - 146929](https://www.omim.org/entry/146929)
See Also
- [CXCL8 (IL-8)](https://pubmed.ncbi.nlm.nih.gov/)
- [Interleukin-8](/entities/interleukin-8)
- [Microglia](/cell-types/microglia-neuroinflammation)
- [Neuroinflammation](/mechanisms/neuroinflammation-pathway)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Multiple Sclerosis](/diseases/multiple-sclerosis)
- [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)
- [Chemokine Signaling](/mechanisms/chemokine-signaling-pathway)
- [Astrocytes](/entities/astrocytes)
Pathway Diagram
The following diagram shows the key molecular relationships involving CXCR1 Gene discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)