title: Cellular fibronectin containing extra domain A promotes arterial thrombosis in mice through platelet Toll-like receptor 4.
abstract: Cellular fibronectin containing extra domain A (Fn-EDA+), which is produced in response to tissue injury in several disease states, has prothrombotic activity and is known to interact with Toll-like-receptor 4 (TLR4). The underlying mechanism and cell types involved in mediating the prothrombotic effect of Fn-EDA+ still remain unknown. Using intravital microscopy, we evaluated susceptibility to carotid artery thrombosis after FeCl3-induced injury in mice expressing Fn lacking EDA (Fn-EDA(-/-) mice) or Fn containing EDA (Fn-EDA(+/+) mice). Fn-EDA(-/-) mice exhibited prolonged times to first thrombus formation and complete occlusion and a significant decrease in the rate of thrombus growth (P < .05 vs Fn-EDA(+/+) mice). Genetic deletion of TLR4 reversed the accelerated thrombosis in Fn-EDA(+/+) mice (P < .05) but had no effect in Fn-EDA(-/-) mice. Bone marrow transplantation experiments revealed that TLR4 expressed on hematopoietic cells contributes to accelerated thrombosis in Fn-EDA(+/+) mice. In vitro studies showed that cellular Fn-EDA+ interacts with platelet TLR4 and promotes agonist-induced platelet aggregation. Finally, Fn-EDA(+/+) mice specifically lacking platelet TLR4 exhibited prolonged times to first thrombus formation and complete occlusion (P < .05 vs Fn-EDA(+/+) mice containing platelet TLR4). We conclude that platelet TLR4 contributes to the prothrombotic effect of cellular Fn-EDA+, suggesting another link between thrombosis and innate immunity.
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa City, IA.
authors.forename: Prem
authors.identifier: http://orcid.org/0000-0001-9501-0065
authors.initials: P
authors.lastname: Prakash
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa City, IA.
authors.forename: Paresh P
authors.initials: PP
authors.lastname: Kulkarni
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa City, IA.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Lentz
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa City, IA.
authors.forename: Anil K
authors.identifier: http://orcid.org/0000-0001-8554-0898
authors.initials: AK
authors.lastname: Chauhan
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D017536:Carotid Artery, Common / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D005353:Fibronectins / Q000235:genetics / Q000378:metabolism*; D007113:Immunity, Innate; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D010974:Platelet Aggregation; D013927:Thrombosis / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
chemical_list: D005353:Fibronectins; D051197:Toll-Like Receptor 4; C574442:extra domain A fibronectin, human