title: Impaired von Willebrand factor adhesion and platelet response in thrombospondin-2 knockout mice.
abstract: Interactions between collagenous extracellular matrices and von Willebrand factor (VWF) are critical for hemostasis and thrombosis. In the present study, we investigated the contribution of an extracellular matrix (ECM) abnormality to the bleeding diathesis in thrombospondin-2 (TSP2) knockout (KO) mice. First, we performed adoptive bone marrow transplantation and observed that introduction of wild-type (WT) marrow into lethally irradiated TSP2 KO mice did not rescue the bleeding diathesis. However, platelets in transplanted mice displayed an inherent aggregation defect, which complicated interpretation. Second, we performed interposition of arterial segments denuded of endothelium. Denuded TSP2 KO arteries grafted into WT mice remained patent in vivo. In contrast, WT grafts underwent thrombosis and were completely occluded within 24 to 48 hours. The nonthrombogenic property of the TSP2 KO ECM was confirmed in vitro by exposing platelets to TSP2 KO dermal fibroblast (DF)-derived ECM. To further probe the effect of TSP2 deficiency, ECM production and deposition by WT and TSP2 KO DFs was analyzed via polymerase chain reaction, immunofluorescence, and scanning electron microscopy and showed similar patterns. In addition, atomic force microscopy (AFM) analysis of WT and TSP2 KO ECM did not reveal differences in stiffness. In contrast, reduced VWF accumulation on TSP2 KO ECM was observed when matrices were subjected to plasma under physiological flow. AFM utilizing VWF-coated 2-μm beads confirmed the weak binding to TSP2 KO ECM, providing a mechanistic explanation for the lack of thrombus formation. Therefore, our studies show that ECM assembly is critical for interaction of collagen with VWF and subsequent thrombogenic responses.
authors.affiliation: Department of Biomedical Engineering, School of Engineering and Applied Science.
authors.forename: Nina
authors.initials: N
authors.lastname: Kristofik
authors.affiliation: Department of Pathology, and.
authors.forename: Nicole E
authors.initials: NE
authors.lastname: Calabro
authors.affiliation: Department of Pathology, and.
authors.forename: Weiming
authors.initials: W
authors.lastname: Tian
authors.affiliation: Department of Biomedical Engineering, School of Engineering and Applied Science.
authors.forename: Aaron
authors.initials: A
authors.lastname: Meng
authors.affiliation: Department of Pathology, and.
authors.forename: Susan
authors.initials: S
authors.lastname: MacLauchlan
authors.affiliation: Department of Pathology, and Department of Surgery, School of Medicine, Yale University, New Haven, CT;
authors.forename: Yinong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Surgery, Nationwide Children's Hospital, Columbus, OH; and.
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Breuer
authors.affiliation: Department of Surgery, School of Medicine, Yale University, New Haven, CT;
authors.forename: George
authors.initials: G
authors.lastname: Tellides
authors.affiliation: Department of Biomedical Engineering, School of Engineering and Applied Science, Department of Anesthesiology, School of Medicine, Yale University, New Haven, CT.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Niklason
authors.affiliation: Department of Biomedical Engineering, School of Engineering and Applied Science, Department of Pathology, and.
authors.forename: Themis R
authors.initials: TR
authors.lastname: Kyriakides
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000378:metabolism / Q000473:pathology*; D002448:Cell Adhesion / Q000502:physiology*; D003094:Collagen / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism / Q000473:pathology; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology*; D006487:Hemostasis; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010973:Platelet Adhesiveness; D013927:Thrombosis / Q000378:metabolism / Q000473:pathology*; D019699:Thrombospondins / Q000502:physiology*; D014841:von Willebrand Factor / Q000378:metabolism*; D000099262:Thrombospondin 2
chemical_list: D003094:Collagen; D019699:Thrombospondins; D014841:von Willebrand Factor; D000099262:Thrombospondin 2