Platelet CD36 mediates interactions with endothelial cell–derived microparticles and contributes to thrombosis in mice
Arunima Ghosh, … , Erin Cockrell, Roy L. Silverstein
Arunima Ghosh, … , Erin Cockrell, Roy L. Silverstein
Published April 22, 2008
Citation Information: J Clin Invest. 2008;118(5):1934-1943. https://doi.org/10.1172/JCI34904.
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Research Article Hematology

Platelet CD36 mediates interactions with endothelial cell–derived microparticles and contributes to thrombosis in mice

Abstract

CD36 is a scavenger receptor that binds multiple ligands, including phosphatidyl serine (PS). Although CD36– mice do not have a bleeding diathesis, we show here that they do have significantly prolonged thrombotic occlusion times in response to FeCl3-induced vascular injury. Because cell-derived microparticles (MPs) are generated in response to vascular injury and circulate in patients with prothrombotic diseases, we hypothesized that PS exposed on their surfaces could be an endogenous CD36 ligand that transmits an activating signal to platelets. We found that MPs prepared from human ECs, monocytes, or platelets or isolated from blood of normal subjects bound to platelets. Binding was not observed with platelets from CD36– donors and was inhibited by an anti-CD36 antibody or by blockade of exposed PS by annexin V or anti-PS IgM. Preincubation of platelets with MPs led to CD36-dependent augmentation of platelet activation in response to low doses of ADP, as assessed by measuring α2bβ3 activation, P-selectin expression, and aggregation. Immunofluorescence confocal microscopy of murine carotid thrombi from CD36– mice showed a significant decrement in endothelial antigen accumulation, which suggests that CD36 plays a role in MP recruitment into thrombi. These results provide what we believe to be a novel role for CD36 in thrombosis.

Authors

Arunima Ghosh, Wei Li, Maria Febbraio, Ricardo G. Espinola, Keith R. McCrae, Erin Cockrell, Roy L. Silverstein

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Figure 6

CD36-dependent enhancement of platelet activation by EMPs in response to low-dose ADP.

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CD36-dependent enhancement of platelet activation by EMPs in response to...
Washed platelets from CD36+ donors (A, B, and E) or CD36– donors (C and D) were incubated with HUVEC-derived EMPs at a 1:9 ratio or buffer control for 30 min and then stimulated with 2 μM ADP. They were then incubated with either PE-conjugated anti–P-selectin (A and C) or FITC-conjugated PAC1 (B, D, and E) and analyzed by flow cytometry. Anti–P-selectin and PAC1 bound to CD36+ platelets when they were preincubated with EMPs. Binding was significantly decreased when platelets were preincubated with anti-CD36 IgG, but not an isotype-matched control IgG. No increase in anti–P-selectin (C) or PAC1 (D) binding was seen using CD36– platelets. (E) PAC1 binding to platelets increased when they were preincubated with human blood–derived MPs. Binding was significantly decreased when platelets were preincubated with anti-CD36 IgG. Histograms are representative of at least 5 different experiments and of 3 independent donors. Bar graphs show mean ± SD from at least 3 separate experiments.