title: P-selectin anchors newly released ultralarge von Willebrand factor multimers to the endothelial cell surface.
abstract: von Willebrand factor (VWF) released from endothelium is ultralarge (UL) and hyperreactive. If released directly into plasma, it can spontaneously aggregate platelets, resulting in systemic thrombosis. This disastrous consequence is prevented by the ADAMTS13 (ADisintegrin and Metalloprotease with ThromboSpondin motif) cleavage of ULVWF into smaller, less active forms. We previously showed that ULVWF, on release, forms extremely long stringlike structures. ADAMTS13 cleaves these strings under flow significantly faster than it does under static conditions. As ULVWF tethering to endothelium is important for its rapid proteolysis, we investigated 2 molecules for their potential to anchor the ULVWF strings: P-selectin and integrin alpha v beta 3. We demonstrated that P-selectin anchors ULVWF to endothelium by several means. First, Chinese hamster ovary (CHO) cells expressing P-selectin specifically adhered to immobilized ULVWF and ULVWF-coated beads to immobilized P-selectin. Second, an anti-VWF antibody coimmunoprecipitates P-selectin from the histamine-activated endothelial cells. Third, P-selectin antibody or soluble P-selectin, but not a alpha v beta 3 antibody, RGDS peptide, or heparin, blocked the formation of ULVWF strings. Fourth, P-selectin expression was in clusters predominantly along the ULVWF strings. Finally, the strength of the minimal ULVWF-P-selectin bond was measured to be 7.2 pN. We, therefore, conclude that P-selectin may anchor ULVWF strings to endothelial cells and facilitate their cleavage by ADAMTS13.
authors: Department of Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
authors: Arnoldo
authors: A
authors: Padilla
authors: Joel L
authors: JL
authors: Moake
authors: Aubrey
authors: A
authors: Bernardo
authors: Chalmette
authors: C
authors: Ball
authors: Yongtao
authors: Y
authors: Wang
authors: Maneesh
authors: M
authors: Arya
authors: Leticia
authors: L
authors: Nolasco
authors: Nancy
authors: N
authors: Turner
authors: Michael C
authors: MC
authors: Berndt
authors: Bahman
authors: B
authors: Anvari
authors: José A
authors: JA
authors: López
authors: Jing-Fei
authors: JF
authors: Dong
mesh_terms: D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001792:Blood Platelets / Q000166:cytology / Q000378:metabolism; D016466:CHO Cells; D002448:Cell Adhesion / Q000502:physiology; D006224:Cricetinae; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D008666:Metalloendopeptidases / Q000378:metabolism; D008863:Microspheres; D019007:P-Selectin / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011233:Precipitin Tests; D013314:Stress, Mechanical; D014471:Umbilical Veins / Q000166:cytology; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D000906:Antibodies; D019007:P-Selectin; D014841:von Willebrand Factor; D051722:ADAM Proteins; D008666:Metalloendopeptidases; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human