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Secretoneurin and chemoattractant receptor interactions
C Kong1, B M Gill, R Rahimpour
1Laboratory of Molecular Inflammation and Immunology, Robarts Research Institute, London, Ontario, Canada.
Journal of Neuroimmunology
|August 4, 1998
Summary
Secretoneurin (SN) is a peptide that attracts monocytes via a novel receptor. This interaction involves signaling pathways sensitive to cholera toxin and pertussis toxin.
Area of Science:
- Immunology
- Cell Biology
- Neuroendocrinology
Background:
- Secretoneurin (SN) is a peptide derived from secretogranin II.
- SN is known to induce chemotaxis in monocytes but not neutrophils.
Purpose of the Study:
- To investigate the mechanism of SN-induced monocyte chemotaxis.
- To identify the receptor and signaling pathways involved in SN's action on monocytes.
Main Methods:
- Monocyte binding assays using radiolabeled SN.
- Competition assays with known chemoattractants (MCP-1, MCP-2, fMLP).
- Intracellular calcium (Ca2+) measurements.
- Inhibition studies using cholera toxin (CT) and pertussis toxin (PT).
- Chemotactic desensitization experiments.
Main Results:
- SN binds to specific cell surface sites on human monocytes.
- SN binding sites are distinct from those of MCP-1, MCP-2, and fMLP, suggesting a novel receptor.
- SN does not induce a rise in cytosolic Ca2+.
- SN-induced chemotaxis is inhibited by CT and PT.
- Cross-desensitization observed between SN and other chemoattractants indicates shared or related signaling pathways.
Conclusions:
- Secretoneurin (SN) binds to a novel cell surface receptor on monocytes.
- SN activates signaling pathways that are sensitive to cholera toxin (CT) and pertussis toxin (PT).
- These findings elucidate the molecular mechanisms underlying SN-mediated monocyte recruitment.