Fusobacterium nucleatum GroEL induces risk factors of atherosclerosis in human microvascular endothelial cells and ApoE-/- mice

Infection and inflammation are risk factors in the initiation and progression of atherosclerosis. Periodontitis is one of the most prevalent chronic inflammations of the oral cavity, and has been reported to be associated with systemic disease. In this study, we evaluated whether the heat-shock protein GroEL of Fusobacterium nucleatum, one of the most prevalent bacteria in periodontitis, induces factors that predispose to atherosclerosis in human microvascular endothelial cells (HMEC-1) and apolipoprotein E-deficient (ApoE-/-) mice. GroEL induced the expression of chemokines such as monocyte chemoattractant protein-1 and interleukin-8 as well as cell adhesion molecules, such as intercellular adhesion molecule 1, vascular cell adhesion molecule 1, and E-selectin. GroEL induced the activity of tissue factor and reduced the activity of the tissue factor pathway inhibitor. Foam cell formation was induced by GroEL. GroEL-injected ApoE-/- mice showed significant atherosclerotic lesion progression compared with control mice. Serum levels of risk factors for atherosclerosis such as interleukin-6, C-reactive protein, and low-density lipoprotein were increased in GroEL-injected ApoE-/- mice compared with control mice, whereas serum levels of high-density lipoprotein were decreased. We could detect significantly higher levels of anti-F.similar to nucleatum GroEL antibody in serum and F.similar to nucleatum DNA in gingival crevicular fluid from patients with periodontitis than in that from healthy subjects. Our results indicate that the host response to the GroEL of periodontal pathogens like F.similar to nucleatum may be a mechanism involved in atherosclerosis, supporting the association of periodontitis and systemic infection.