CD95-ligand contributes to abdominal aortic aneurysm progression by modulating inflammation

Area of Science:

• Vascular Biology
• Immunology
• Cell Death Pathways

Background:

• Abdominal aortic aneurysm (AAA) involves inflammation, matrix degradation, and smooth muscle cell apoptosis.
• CD95L, an inflammatory mediator and apoptosis inducer, is elevated in AAA tissues.
• The specific role of CD95L/CD95 signaling in AAA pathogenesis and potential therapeutic inhibition remain unclear.

Purpose of the Study:

• To investigate the role of CD95L and its downstream target, caspase 8, in AAA progression.
• To determine if blocking CD95L signaling can mitigate AAA development.

Main Methods:

• Utilized a CaCl2-induced murine model of AAA in wild-type and CD95L null mice.
• Employed chimeric mice with CD95L deficient bone marrow transplantation.
• Administered a caspase 8-specific inhibitor to assess its effect on aneurysm development.

Main Results:

• CD95L deficiency significantly reduced aortic diameter and medial elastic lamellae damage in AAA models.
• CD95L deletion attenuated macrophage and T cell infiltration into aortic tissue.
• CD95L deficiency inhibited caspase 8 expression, and a caspase 8 inhibitor partially blocked aneurysm development.

Conclusions:

• Inflammatory cell infiltration in AAA formation is dependent on CD95L expressed by myeloid cells.
• Inhibition of AAA by CD95L deletion is partly mediated by the down-regulation of caspase 8.
• CD95L/caspase 8 signaling represents a potential therapeutic target for abdominal aortic aneurysms.