Differential surface activation of the A1 domain of von Willebrand factor

Citation

Tronic, E. H.; Yakovenko, O.; Weidner, T.; Baio, J. E.; Penkala, R.; Castner, D. G.; & Thomas, W. E. (2016). Differential surface activation of the A1 domain of von Willebrand factor. Biointerphases, 11(2).

Abstract

The clotting protein von Willebrand factor (VWF) binds to platelet receptor glycoprotein Iba (GPIb alpha) when VWF is activated by chemicals, high shear stress, or immobilization onto surfaces. Activation of VWF by surface immobilization is an important problem in the failure of cardiovascular implants, but is poorly understood. Here, the authors investigate whether some or all surfaces can activate VWF at least in part by affecting the orientation or conformation of the immobilized GPIb alpha-binding A1 domain of VWF. Platelets binding to A1 adsorbed onto polystyrene surfaces translocated rapidly at moderate and high flow, but detached at low flow, while platelets binding to A1 adsorbed onto glass or tissue-culture treated polystyrene surfaces translocated slowly, and detached only at high flow. Both x-ray photoelectron spectroscopy and conformation independent antibodies reported comparable A1 amounts on all surfaces. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and near-edge x-ray absorption fine structure spectra suggested differences in orientation on the three surfaces, but none that could explain the biological data. Instead, ToF-SIMS data and binding of conformation-dependent antibodies were consistent with the stabilization of an alternative more activated conformation of A1 by tissue culture polystyrene and especially glass. These studies demonstrate that different material surfaces differentially affect the conformation of adsorbed A1 domain and its biological activity. This is important when interpreting or designing in vitro experiments with surface-adsorbed A1 domain, and is also of likely relevance for blood-contacting biomaterials. (C) 2016 Author(s).

Keyword(s)

adsorbed protein films
conformational-changes
force-dependent binding
gpib-alpha
ion mass-spectrometry
ix-v complex
monoclonal-antibodies
platelet glycoprotein ib
terminal flanking region
tof-sims

Notes

Dr0ff
Times Cited:3
Cited References Count:69

Reference Type

Journal Article

Secondary Title

Biointerphases

Author(s)

Tronic, E. H.
Yakovenko, O.
Weidner, T.
Baio, J. E.
Penkala, R.
Castner, D. G.
Thomas, W. E.

Year Published

2016

Date Published

1464739200

Volume Number

11

Issue Number

2

ISSN/ISBN

1934-8630

DOI

Artn 029803
10.1116/1.4943618