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Modulation of cell adhesion by tyrosine kinases and phosphatases inhibitors
M Stefănescu1, C Matache, A Onu
1Cantacuzino Institute, Immunology Department, Bucharest, Romania.
Abstract:
Integrin-mediated activation of monocytes is an important aspect involved in the increase of proinflammatory cytokine messages. Tyrosine phosphorylation of proteins is one of the earliest events involved in these processes: Therefore, we selected two inhibitors, one for tyrosine kinases (quercitin) and another for tyrosine phosphatases (sodium orthovanadate) and we studied their capacity to modulate monocyte adhesion to fibronectin. Our results showed that quercitin strongly inhibits both tyrosine phosphorylation and cell adhesion. Sodium orthovanadate induces a modest increase of tyrosine phosphorylation and a weak enhancement of cell adhesion. When a combination of the two inhibitors was used, the tyrosine phosphorylation level displayed a strong enhancement. In contrast, cell adhesion was inhibited, but to the same degree. These observations indicate that tyrosine kinases may be more important than tyrosine phosphatases in the modulation of cell adhesion by flavonoid compounds.
Insights
Flavonoid compounds like quercetin can inhibit monocyte adhesion by affecting tyrosine phosphorylation. Tyrosine kinases play a key role in modulating this cell adhesion process.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Integrin-mediated monocyte activation increases proinflammatory cytokine production.
- Tyrosine phosphorylation is an early event in monocyte activation.
Purpose of the Study:
- To investigate the role of tyrosine kinases and phosphatases in monocyte adhesion to fibronectin.
- To determine the effect of quercetin and sodium orthovanadate on monocyte adhesion and tyrosine phosphorylation.
Main Methods:
- Monocyte adhesion assays to fibronectin.
- Inhibition of tyrosine kinases with quercetin.
- Inhibition of tyrosine phosphatases with sodium orthovanadate.
Main Results:
- Quercetin strongly inhibited both tyrosine phosphorylation and monocyte adhesion.
- Sodium orthovanadate showed a modest increase in tyrosine phosphorylation and weak enhancement of cell adhesion.
- Combined inhibition led to enhanced tyrosine phosphorylation but inhibited cell adhesion.
Conclusions:
- Tyrosine kinases are more critical than tyrosine phosphatases in modulating monocyte adhesion.
- Flavonoid compounds, specifically quercetin, demonstrate potential in regulating inflammatory responses via tyrosine kinase inhibition.