Nitric oxide production and MDR expression by human brain endothelial cells

Area of Science:

• Neuroscience
• Cell Biology
• Immunology

Background:

• The endothelium plays a crucial role in responding to inflammatory signals like cytokines.
• Nitric oxide (NO) production, particularly via inducible nitric oxide synthase (iNOS), is stimulated by tumor necrosis factor (TNF).
• NO is vital for neural transmission and vasodilation.

Purpose of the Study:

• To investigate the impact of TNF and Staphylococcus aureus on NO production in brain endothelial cells.
• To examine the effect of these agents on multidrug resistance (MDR) expression and function in endothelial cells.

Main Methods:

• In vitro culture of brain endothelial cells.
• Stimulation with TNF and Staphylococcus aureus.
• Measurement of NO production.
• Western blot analysis for iNOS expression.
• Flow cytometry for P-glycoprotein expression and MDR function analysis.

Main Results:

• Both TNF and Staphylococcus aureus significantly enhanced NO production.
• Enhanced iNOS expression was observed, which was reversible with pentoxifylline (a TNF synthesis inhibitor).
• TNF did not alter P-glycoprotein expression but reduced the overall MDR function of brain capillary endothelial cells.

Conclusions:

• Brain endothelial cells are responsive to TNF and Staphylococcus aureus, with increased NO production.
• A potential connection exists between NO production and MDR function in endothelial cells.
• These findings are significant for understanding blood-brain barrier regulation and the effects of inflammatory agents.