Shed membrane particles from T lymphocytes impair endothelial function and regulate endothelial protein expression

Area of Science:

• Vascular Biology
• Cellular Signaling
• Immunology

Background:

• Microparticles (MPs) are procoagulant and proinflammatory vesicles released during cell activation.
• T lymphocyte-derived MPs are implicated in various pathological conditions.

Purpose of the Study:

• To investigate the impact of T lymphocyte-derived MPs on vascular endothelial function.
• To elucidate the molecular mechanisms underlying MP-induced endothelial dysfunction.

Main Methods:

• MPs were generated from a human T cell line.
• Mouse aortic rings and small mesenteric arteries were used to assess vascular responses.
• Endothelial function was evaluated by measuring relaxation to acetylcholine and shear stress.
• Protein expression levels of endothelial NO synthase (eNOS) and caveolin-1 were analyzed.

Main Results:

• T cell-derived MPs impaired acetylcholine-induced relaxation in aortic rings and shear stress-induced dilatation in mesenteric arteries.
• The impairment involved alterations in nitric oxide (NO) and prostacyclin pathways.
• MP effects were attributed to decreased eNOS expression and increased caveolin-1 expression.
• MPs from diabetic patients and circulating MPs from diabetic or HIV-infected patients also reduced eNOS expression.

Conclusions:

• T lymphocyte-derived MPs induce endothelial dysfunction in both large and small arteries.
• MPs alter NO and prostacyclin pathways by modulating eNOS and caveolin-1 expression.
• These findings enhance understanding of the role of circulating MPs in cardiovascular and immune diseases.