P-selectin anchors newly released ultralarge von Willebrand factor multimers to the endothelial cell surface.
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.
Padilla
Arnoldo
A
Department of Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
Moake
Joel L
JL
Bernardo
Aubrey
A
Ball
Chalmette
C
Wang
Yongtao
Y
Arya
Maneesh
M
Nolasco
Leticia
L
Turner
Nancy
N
Berndt
Michael C
MC
Anvari
Bahman
B
López
José A
JA
Dong
Jing-Fei
JF
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*
D000906:Antibodies; D019007:P-Selectin; D014841:von Willebrand Factor; D051722:ADAM Proteins; D008666:Metalloendopeptidases; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human