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Arterioscler Thromb Vasc Biol. 2014 Apr;34(4):801-9. doi: 10.1161/ATVBAHA.114.303287. Epub 2014 Feb 20.

Human cytomegalovirus-platelet interaction triggers toll-like receptor 2-dependent proinflammatory and proangiogenic responses.

Author information

1
From the Department of Medicine, Centre for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden (A.A., K.C.Y., E.K., Y.W., A.-A.M., P.R., A.R., L.M.B., C.S.-N.); Institute of Physiology, Centre for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria (A.A., J.B.K., W.C.S., G.S.); Postgraduate School of Molecular Medicine, Department of Internal Medicine and Hypertension, Medical University of Warsaw, Warsaw, Poland (E.K.); and Department of Geriatrics, Qilu Hospital, Shandong University, Jinan, China (Y.W.).

Abstract

OBJECTIVE:

Human cytomegalovirus (HCMV) is a widespread pathogen that correlates with various clinical complications, including atherosclerosis. HCMV is released into the circulation during primary infection and periodic viral reactivation, allowing virus-platelet interactions. Platelets are important in the onset and development of atherosclerosis, but the consequences of platelet-HCMV interactions are unclear.

APPROACH AND RESULTS:

We studied the effects of HCMV-platelet interactions in blood from healthy donors using the purified clinical HCMV isolate VR1814. We demonstrated that HCMV bound to a Toll-like receptor (TLR) 2-positive platelet subpopulation, which resulted in signal transduction, degranulation, and release of proinflammatory CD40L and interleukin-1β and proangiogenic vascular endothelial-derived growth factor. In mice, murine CMV activated wild-type but not TLR2-deficient platelets. However, supernatant from murine CMV-stimulated wild-type platelets also activated TLR2-deficient platelets, indicating that activated platelets generated soluble mediators that triggered further platelet activation, independent of TLR2 expression. Inhibitor studies, using ADP receptor antagonists and apyrase, revealed that ADP release is important to trigger secondary platelet activation in response to HCMV. HCMV-activated platelets rapidly bound to and activated neutrophils, supporting their adhesion and transmigration through endothelial monolayers. In an in vivo model, murine CMV induced systemic upregulation of platelet-leukocyte aggregates and plasma vascular endothelial-derived growth factor in mice and showed a tendency to enhance neutrophil extravasation in a TLR2-dependent fashion.

CONCLUSIONS:

HCMV is a well-adapted pathogen that does not induce immediate thrombotic events. However, HCMV-platelet interactions lead to proinflammatory and proangiogenic responses, which exacerbate tissue damage and contribute to atherogenesis. Therefore, platelets might contribute to the effects of HCMV in accelerating atherosclerosis.

KEYWORDS:

atherosclerosis; blood platelets; cytomegalovirus; toll-like receptors

PMID:
24558109
DOI:
10.1161/ATVBAHA.114.303287
[Indexed for MEDLINE]
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