Modulation of phorbol ester-induced respiratory burst by vanadate, genistein, and phenylarsine oxide in mouse macrophages
Related Experiment Videos
M Conde1, M D Chiara, E Pintado
1Departmento de Bioquímica Médica y Biología Molecular, Facultad de Medicina, Universidad de Sevilla, Spain.
Abstract:
The effect of the inhibitors of tyrosine phosphatase (vanadate and phenylarsine oxide) and of an inhibitor of tyrosine kinase (genistein) on O2.- production in mouse peritoneal macrophages was examined. Vanadate and phenylarsine oxide produced a dose-dependent inhibition of phorbol myristate acetate (PMA)-induced O2.- production, whereas genistein potentiated O2.- production triggered by phorbol ester. Vanadate had no effect on the respiratory burst in human neutrophils challenged with fMLP, in agreement with previously published data on human intact neutrophils. It did not alter reduced nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase activity in membrane preparations of mouse peritoneal macrophages. These data suggest that the phosphorylation of protein(s) in tyrosine residues blocked the PMA-dependent respiratory burst in mouse macrophages.
Insights
Tyrosine phosphatase inhibitors blocked oxygen (O2.-) production in mouse macrophages stimulated by phorbol myristate acetate (PMA). Conversely, a tyrosine kinase inhibitor enhanced this response, suggesting a role for tyrosine phosphorylation.
Area of Science:
- Immunology
- Cellular Biology
- Biochemistry
Background:
- The respiratory burst, involving oxygen (O2.-) production, is a key function of phagocytic cells like macrophages.
- Protein tyrosine phosphorylation plays critical roles in cellular signaling pathways, including immune responses.
Purpose of the Study:
- To investigate the role of tyrosine phosphorylation in regulating oxygen (O2.-) production in mouse peritoneal macrophages.
- To examine the effects of tyrosine phosphatase and tyrosine kinase inhibitors on macrophage respiratory burst activity.
Main Methods:
- Mouse peritoneal macrophages were treated with vanadate and phenylarsine oxide (tyrosine phosphatase inhibitors) or genistein (tyrosine kinase inhibitor).
- Oxygen (O2.-) production was measured following stimulation with phorbol myristate acetate (PMA).
- Reduced nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase activity was assessed in macrophage membrane preparations.
Main Results:
- Vanadate and phenylarsine oxide inhibited PMA-induced O2.- production in a dose-dependent manner.
- Genistein potentiated PMA-induced O2.- production.
- Vanadate did not affect O2.- production in human neutrophils or NADPH-oxidase activity in macrophage membranes.
Conclusions:
- Tyrosine phosphorylation appears to negatively regulate the phorbol ester-dependent respiratory burst in mouse macrophages.
- Inhibition of tyrosine phosphatases blocks O2.- production, while inhibition of tyrosine kinases enhances it.
- These findings highlight the involvement of tyrosine phosphorylation in controlling macrophage oxidative responses.