Treponema pallidum induces the activation of endothelial cells via macrophage-derived exosomes

Area of Science:

• Immunology
• Cell Biology
• Pathogenesis

Background:

• Exosomes are implicated in inflammatory diseases and tumors.
• Treponema pallidum causes syphilis, a complex infectious disease.
• The role of exosomes in syphilis pathogenesis remains unclear.

Purpose of the Study:

• To investigate the impact of exosomes derived from Treponema pallidum-infected macrophages on vascular endothelial cells.
• To determine if these exosomes influence endothelial cell adhesion, permeability, and cytokine secretion.
• To elucidate the potential role of these exosomes in syphilis pathogenesis.

Main Methods:

• Established a rabbit model of syphilis infection to obtain Treponema pallidum.
• Isolated and characterized exosomes from T. pallidum-infected macrophages using electron microscopy, western blot, and nanoparticle tracking analysis.
• Evaluated human umbilical vein endothelial cell adhesion, permeability, and cytokine secretion (ICAM-1, VCAM-1, VEGF, IL-8) in a co-culture system.

Main Results:

• Exosomes from T. pallidum-infected macrophages significantly enhanced endothelial cell adhesion and permeability.
• Elevated levels of cytokines, including ICAM-1, VCAM-1, VEGF, and IL-8, were observed in the experimental group.
• This is the first study to demonstrate these specific effects of T. pallidum-induced macrophage-derived exosomes.

Conclusions:

• Exosomes derived from T. pallidum-infected macrophages alter vascular endothelial cell behavior.
• These exosome-mediated changes in adhesion, permeability, and cytokine profiles may contribute to the pathogenesis of syphilis.
• Further research into exosome-targeted therapies for syphilis is warranted.