Analysis of Fractalkine Receptor CX(3)CR1 Function by Targeted Deletion and Green Fluorescent Protein Reporter Gene Insertion
Overview
Affiliations
The seven-transmembrane receptor CX(3)CR1 is a specific receptor for the novel CX(3)C chemokine fractalkine (FKN) (neurotactin). In vitro data suggest that membrane anchoring of FKN, and the existence of a shed, soluble FKN isoform allow for both adhesive and chemoattractive properties. Expression on activated endothelium and neurons defines FKN as a potential target for therapeutic intervention in inflammatory conditions, particularly central nervous system diseases. To investigate the physiological function of CX(3)CR1-FKN interactions, we generated a mouse strain in which the CX(3)CR1 gene was replaced by a green fluorescent protein (GFP) reporter gene. In addition to the creation of a mutant CX(3)CR1 locus, this approach enabled us to assign murine CX(3)CR1 expression to monocytes, subsets of NK and dendritic cells, and the brain microglia. Analysis of CX(3)CR1-deficient mice indicates that CX(3)CR1 is the only murine FKN receptor. Yet, defying anticipated FKN functions, absence of CX(3)CR1 interferes neither with monocyte extravasation in a peritonitis model nor with DC migration and differentiation in response to microbial antigens or contact sensitizers. Furthermore, a prominent response of CX(3)CR1-deficient microglia to peripheral nerve injury indicates unimpaired neuronal-glial cross talk in the absence of CX(3)CR1.
Centripetal migration and prolonged retention of microglia promotes spinal cord injury repair.
Ye J, Shan F, Xu X, Liang C, Zhang N, Hu H J Neuroinflammation. 2025; 22(1):77.
PMID: 40075472 PMC: 11905688. DOI: 10.1186/s12974-025-03411-9.
Comprehensive analysis of myeloid reporter mice.
Wang Y, Dowling S, Rodriguez V, Maciuch J, Mayer M, Therron T bioRxiv. 2025; .
PMID: 40060446 PMC: 11888320. DOI: 10.1101/2025.02.24.639159.
Tissue macrophages: origin, heterogenity, biological functions, diseases and therapeutic targets.
Guan F, Wang R, Yi Z, Luo P, Liu W, Xie Y Signal Transduct Target Ther. 2025; 10(1):93.
PMID: 40055311 PMC: 11889221. DOI: 10.1038/s41392-025-02124-y.
Sirerol-Piquer M, Perez-Villalba A, Duart-Abadia P, Belenguer G, Gomez-Pinedo U, Blasco-Chamarro L Mol Neurodegener. 2025; 20(1):26.
PMID: 40038767 PMC: 11881471. DOI: 10.1186/s13024-025-00816-1.
Chen J, Kitagawa Y, Xie F, Li H, Kem W, You Z J Cachexia Sarcopenia Muscle. 2025; 16(2):e13755.
PMID: 40035088 PMC: 11876847. DOI: 10.1002/jcsm.13755.