Macrophage Stimulating Protein (MSP) evokes superoxide anion production by human macrophages of different origin
Article first published online: 29 JAN 2009
2001 British Pharmacological Society
British Journal of Pharmacology
Volume 134, Issue 6, pages 1285–1295, November 2001
How to Cite
Brunelleschi, S., Penengo, L., Lavagno, L., Santoro, C., Colangelo, D., Viano, I. and Gaudino, G. (2001), Macrophage Stimulating Protein (MSP) evokes superoxide anion production by human macrophages of different origin. British Journal of Pharmacology, 134: 1285–1295. doi: 10.1038/sj.bjp.0704356
- Issue published online: 29 JAN 2009
- Article first published online: 29 JAN 2009
- (Received June 20, 2001, Accepted August 29, 2001)
- Macrophage Stimulating Protein (MSP);
- superoxide anion production;
- cellular activation;
- signal transduction;
- protein kinases/phosphatases
Macrophage Stimulating Protein (MSP), a serum factor related to Hepatocyte Growth Factor, was originally discovered to stimulate chemotaxis of murine resident peritoneal macrophages. MSP is the ligand for Ron, a member of the Met subfamily of tyrosine kinase receptors. The effects of MSP on human macrophages and the role played in human pathophysiology have long been elusive.
We show here that human recombinant MSP (hrMSP) evokes a dose-dependent superoxide anion production in human alveolar and peritoneal macrophages as well as in monocyte-derived macrophages, but not in circulating human monocytes. Consistently, the mature Ron protein is expressed by the MSP responsive cells but not by the unresponsive monocytes. The respiratory burst evoked by hrMSP is quantitatively higher than the one induced by N-formylmethionyl-leucyl-phenylalanine and similar to phorbol myristate acetate-evoked one.
To investigate the mechanisms involved in NADPH oxidase activation, leading to superoxide anion production, different signal transduction inhibitors were used. By using the non selective tyrosine kinase inhibitor genistein, the selective c-Src inhibitor PP1, the tyrosine phosphatase inhibitor sodium orthovanadate, the phosphatidylinositol 3-kinase inhibitor wortmannin, the p38 inhibitor SB203580, the MEK inhibitor PD098059, we demonstrate that hrMSP-evoked superoxide production is mediated by tyrosine kinase activity, requires the activation of Src but not of PI 3-kinase. We also show that MAP kinase and p38 signalling pathways are involved.
These results clearly indicate that hrMSP induces the respiratory burst in human macrophages but not in monocytes, suggesting for the MSP/Ron complex a role of activator as well as of possible marker for human mature macrophages.
British Journal of Pharmacology (2001) 134, 1285–1295; doi:10.1038/sj.bjp.0704356