Fractalkine Signaling in Neuroinflammatory and Tumor Microenvironments

Fractalkine (CX3CL1) exists as both a membrane-anchored glycoprotein on neurons and, upon proteolytic cleavage, as a soluble chemokine that engages the CX3CR1 receptor on microglia and mononuclear phagocytes. This ligand–receptor pair constitutes a pivotal neuron–glia communication axis that fine-tunes microglial activation, migration and phagocytosis. In neuroinflammatory settings, fractalkine signalling exerts a homeostatic influence by restraining excessive cytokine release, promoting clearance of cellular debris and supporting synaptic remodelling. Perturbations of this axis have been implicated in neurodegenerative diseases—where altered CX3CR1 expression or abnormal ligand processing contribute to pathological microglial phenotypes—and in acute central nervous system injuries, where timely fractalkine delivery can enhance neuronal survival and regenerative outcomes. Beyond the nervous system, fractalkine signalling shapes the tumour microenvironment by modulating macrophage recruitment, survival and polarisation. Elevated CX3CL1–CX3CR1 interactions may drive lymphangiogenesis and facilitate metastatic spread in aggressive cancers, though in certain contexts they can also bolster anti-tumour immune surveillance. Together, these multifaceted roles underscore fractalkine signalling as a convergent pathway linking neuroinflammation and cancer progression, and as a compelling target for therapeutic intervention.

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Fractalkine Signaling in Neuroinflammatory and Tumor Microenvironments publication trend

The graph below shows the total number of articles in fractalkine signaling in neuroinflammatory and tumor microenvironments across all publications each year (not limited to Nature Index journals).

Technical terms

Fractalkine (CX3CL1): A unique chemokine expressed as a membrane-bound and soluble ligand that signals through CX3CR1.

CX3CR1: A G protein-coupled receptor on microglia and certain monocytes/macrophages, mediating responses to fractalkine.

Microglia: Resident immune cells of the central nervous system that survey the environment, remove debris and regulate inflammation.

Neuroinflammation: An immune response in the nervous system characterised by activation of glial cells and release of inflammatory mediators.

Tumour microenvironment: The cellular and molecular milieu surrounding a tumour, including immune, stromal and endothelial elements that influence cancer progression.

Lymphangiogenesis: The formation of new lymphatic vessels, often exploited by tumours to facilitate metastatic dissemination.

References

1. Neuron–glia crosstalk in health and disease: fractalkine and CX3CR1 take centre stage. Open Biology (2013).
2. Fractalkine isoforms differentially regulate microglia-mediated inflammation and enhance visual function in the diabetic retina. Journal of Neuroinflammation (2024).
3. CX3CL1-CX3CR1 axis protects retinal ganglion cells by inhibiting microglia activation in a distal optic nerve trauma model. Inflammation and Regeneration (2024).
4. Double-faced CX3CL1 enhances lymphangiogenesis-dependent metastasis in an aggressive subclone of oral squamous cell carcinoma. JCI Insight (2024).
5. Chemokine receptor CX3CR1 contributes to macrophage survival in tumor metastasis. Molecular Cancer (2013).
6. Neuroinflammation and fractalkine signaling in Alzheimer’s disease. Journal of Neuroinflammation (2019).
7. Analysis of the Role of CX3CL1 (Fractalkine) and Its Receptor CX3CR1 in Traumatic Brain and Spinal Cord Injury: Insight into Recent Advances in Actions of Neurochemokine Agents. Molecular Neurobiology (2016).