Propolypeptide and mature portions of von Willebrand factor of bovine origin recognize different sites on type‐I collagen obtained from bovine tendon

Usui, Tomoko; Fujisawa, Tomoyuki; Takagi, Junichi; Saito, Yuji

doi:10.1111/j.1432-1033.1992.tb16788.x

Cited by 12 publications

(10 citation statements)

References 31 publications

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“…37 Collagen monomers may offer a way to study the role and donor variability of GP Ia/IIa, which are likely to be associated with certain receptor polymorphisms and even thrombotic events. 44,45 The differences between native-type collagen fibrils and monomers cannot be explained by differential vWF-binding capacity, because (1) vWF binding to collagen has been reported to be cation-independent, 46 (2) the vWF-dependent increase in platelet deposition was observed on both substrates in PPACK-anticoagulated blood, (3) it was similarly inhibited by ATA, 39 and (4) incubation of the monomer surface with vWF before perfusion (citrated blood, high shear rate) was unable to correct for the lacking platelet deposition, in contrast to restoration of the physiological Mg 2ϩ concentration.…”

Section: Discussionmentioning

confidence: 99%

Studies of Adhesion-Dependent Platelet Activation

Siljander

Lassila

1999

ATVB

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Abstract-The molecular differences between native-type collagen type I fibrils (NC) and their pepsinated monomers (PC) were used to uncover receptors involved in platelet-collagen interaction along the adhesion-activation axis. The platelet-depositing capacity of NC and PC under blood flow and their adhesive properties and respective morphologies, aggregation, procoagulant capacity, and tyrosine phosphorylation were compared under different cationic milieus, including or excluding the glycoprotein (GP) Ia/IIa. NC was consistently a more preferable and activating substrate than PC during flow (5 minutes) and in platelet aggregation. In PPACK-treated blood, both NC (3.3-fold) and PC (2.7-fold) increased platelet attachment on elevation of the shear rate from 500 to 1640 s Ϫ1, whereas in citrated blood, adhesion and thrombus growth on PC were negligible under the high shear rate, unlike on NC (1.9-fold increase). The complete lack of platelet deposition on PC in citrated blood could be overcome by restoring physiological Mg 2ϩ concentration, and in contrast to NC, platelets interacting with PC were highly dependent on Mg 2ϩ during adhesion, aggregation, and procoagulant response. Monoclonal antibody (mAb 131.7) against GP IV inhibited platelet deposition to NC in citrated blood (2 minutes) by 49%, which was not further increased by coincubation with mAb against GP Ia (6F1). These results stress the importance of GP Ia/IIa in shear-resistant platelet deposition on collagen monomers. In native fibers, however, the preserved quaternary structure with telopeptides activates additional platelet receptors capable of substituting GP Ia/IIa and GP IV. Pathophysiological platelet-collagen interactions include bleeding disorders due to either defective receptors or autoantibodies 2,3,5 or to impaired collagen synthesis, 6 -8 indicating several functional determinants on both the platelets and collagen.Thus far, glycoprotein (GP) Ia/IIa, integrin ␣ 2 ␤ 1 , has been recognized as the major platelet receptor for collagen in primary adhesion, and accordingly, dysfunctional GP Ia/IIa associates with prolonged bleeding tendencies in patients. 9 -11 Although GP IV has been implicated in the very early phases of adhesion, the impact of GP IV, 12-14 as well as the other receptor candidates, 15-17 on hemostasis has remained unsettled. GP VI is involved in collagen-induced platelet activation, evidenced both by a poor aggregation response in patients lacking this receptor 5 and by collagen-related peptides that likely induce strong platelet aggregation in normal platelets via this receptor. 18,19 However, patients lacking GP VI have only mild bleeding tendencies, 5 and under blood flow, the collagen-related peptides are unable to retain firm adhesion. 20 Qualitative differences in collagen preparations complicate the identification of the determinants in plateletcollagen interaction. The term "native collagen fibers" has been used to cover a spectrum of preparations, from suspensions of native fibrils (eg, Horm) to dialysed fibrils...

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Section: Discussionmentioning

confidence: 99%

Studies of Adhesion-Dependent Platelet Activation

Siljander

Lassila

1999

ATVB

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“…During the biosynthesis, pp-vWF governs the multimer assembly of the mature vWF which is essential for its biological functions such as stabilization of factor VIII [24]. pp-vWF was found to bind to collagen, like the mature vWF, but the binding properties of these proteins are critically different in that the binding of pp-vWF to fibrillar type I collagen is very sensitive to the pepsin treatment of collagen while the binding of the mature vWF is not significantly affected [17]. pp-vWF inhibits platelet-collagen interaction while the mature vWF potentiates it [lo, 141.…”

Section: Discussionmentioning

confidence: 99%

“…pp-vWF was purified from washed bovine platelets by an immunoaffinity chromatography as described previously [17]. vWF was purified from fresh bovine plasma according to the method of Kirby [18].…”

Section: Adhesive Proteins and Antibodiesmentioning

confidence: 99%

β1‐integrin‐mediated adhesion of melanoma cells to the propolypeptide of von Willebrand factor

Takagi

Sudo

Saito

et al. 1994

European Journal of Biochemistry

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Cell-adhesion activity of the bovine propolypeptide of von Willebrand factor (pp-vWF) was assessed by means of an in vitro assay with several cell lines of both normal and tumor-cell origin. pp-vWF promoted adhesion and spreading of B16 mouse melanoma cells and G-361 human melanoma cells. However, it could not induce adhesion of any other cell lines tested including endothelial cells, normal fibroblasts, and tumor cells of sarcoma, carcinoma, neuroblastoma and leukemia origin. A monospecific polyclonal antibody against pp-vWF, but not against fibronectin, laminin, and von Willebrand factor (vWF), completely blocked the pp-vWF-mediated adhesion, indicating that the cell adhesion was due to the pp-vWF molecule and not due to possible contamination of these three well-known adhesive proteins. The cell-adhesion activity was also observed with human ppvWF and, furthermore, the adhesion to both bovine and human pp-vWF was not affected by a peptide containing the Arg-Gly-Asp sequence while the peptide abolished the cell adhesion to vWF. The adhesion was completely dependent on Mg2+ and inhibited by Ca"'. Inhibition by an anti-(pl integrin) mAb (4B4) indicates that the receptor for this protein belongs to the pl-integrin family. A monoclonal antibody (TC4) among several antibodies directed against bovine pp-vWF inhibited the B16 adhesion to immobilized pp-vWF. The epitope for this monoclonal antibody lies in a central 8-kDa portion of pp-vWF, suggesting that this region is important for the cell-adhesion activity. This idea was supported by the finding that purified 8-kDa fragment promoted adhesion of B16 cells in a concentration-dependent manner. As pp-vWF shows unique cell-type specificity in its adhesion activity, which is completely different from that of fibronectin, laminin, vWF and collagen, it may be a novel type of adhesive glycoprotein that utilizes a Dl-integrin receptor.The adhesion of cells to extracellular matrix (ECM) proteins is a key step involved in modulating the morphology, proliferation, differentiation, and migration of cells. This process is mediated by interactions between specific cell surface receptors and specific matrix proteins. Different cells adhere to different adhesive proteins due to the differential expression of surface receptors. It is well known that many cells adhere to fibronectin, laminin and collagen through more than one class of receptors including various integrins [ l , 21. Although these three proteins are abundant in ECM and thought to be primarily important in tissue organization under physiological conditions, there are a number of other proteins that have cell-adhesion activity in vitro and are thought to play a crucial role in more specialized stages of cellular events. [7]. A large amount of evidence is accumulating that these adhesive glycoproteins play dynamic roles in embryo-

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“…Synthetic peptides GRGDSP and DELPQLVTLPHPNLHGPEILDVPST (CS1) were purchased from Sigma. pp-vWF was purified from bovinewashed platelets by immunoaffinity chromatography as described previously (23).…”

Section: Methodsmentioning

confidence: 99%

Propolypeptide of von Willebrand Factor Is a Novel Ligand for Very Late Antigen-4 Integrin

Isobe

Hisaoka

Shimizu

et al. 1997

Journal of Biological Chemistry

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We have previously reported that propolypeptide of von Willebrand factor (pp-vWF) promotes melanoma cell adhesion in a ␤1 integrin-dependent manner. In this report, we identified the ␣ subunit of the cell adhesion receptor for pp-vWF as ␣4. Human leukemia cell lines that express ␣4␤1 integrin (very late antigen-4, VLA-4), but not cell lines which lack VLA-4, attached well to pp-vWF substrate and these adhesions were completely inhibited by anti-␣4 integrin monoclonal antibody HP2/1. Adhesion of mouse melanoma expressing ␣4 integrin was also inhibited by anti-mouse ␣4 mAb PS/2. Furthermore, transfection of human ␣4 cDNA into ␣4 ؊ Chinese hamster ovary cells resulted in an acquisition of adhesive activity to pp-vWF, indicating that pp-vWF is a ligand for VLA-4 integrin. Using a recombinant fragment of pp-vWF, the cell attachment site was shown to be located within amino acid residues 376 -455 of ppvWF. A series of synthetic peptides covering this region were tested for the ability to promote cell attachment and a 15-residue peptide designated T2-15 (DCQDHSF-SIVIETVQ, residues numbered 395-409) promoted VLA-4 dependent cell adhesion. The peptide was also capable of inhibiting cell adhesion to pp-vWF, suggesting that this sequence represents the cell attachment site. By affinity chromatography using peptide T2-15-Sepharose, it was found that ␣4␤1 integrin complex from extracts of surface iodinated B16 cells specifically bound to the peptide. These results strongly suggest that pp-vWF is a novel physiological ligand for VLA-4.Propolypeptide of von Willebrand factor (pp-vWF), 1 which is also called von Willebrand antigen II (1), is an unusually large propolypeptide (ϳ100 kDa) produced only in endothelial cells and megakaryocytes together with blood coagulation protein von Willebrand factor (2). It is processed from a large precursor of vWF (prepro-vWF) during biosynthesis and stored in the granule of both endothelial cells and platelets independent from mature vWF (3, 4). We have been investigating the biological functions of pp-vWF and found that pp-vWF bound to collagen and inhibited collagen-induced platelet aggregation in contrast to the mature vWF (5, 6). Furthermore, we have found that pp-vWF serves as a substrate for transglutaminase and is specifically cross-linked to laminin (7), suggesting a possibility that it acts as transient matrix protein upon secretion from platelets and endothelial cells at the site of vascular injury. In a previous paper (8), we reported that pp-vWF promoted the attachment and spreading of melanoma cells. The receptor responsible for this adhesion was the ␤1 class of integrin but the corresponding ␣ subunit could not be identified.Integrins are heterodimeric transmembrane proteins consisting of ␣ and ␤ subunits and mediate cell adhesion to extracellular matrix proteins as well as cell-cell interactions (9 -12). To date more than 15 ␣ subunits and 8 ␤ subunits have been identified and combination of ␣ and ␤ subunits determines the ligand specificity of individual integrins. Integrin-m...

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Propolypeptide and mature portions of von Willebrand factor of bovine origin recognize different sites on type‐I collagen obtained from bovine tendon

Cited by 12 publications

References 31 publications

Studies of Adhesion-Dependent Platelet Activation

Studies of Adhesion-Dependent Platelet Activation

β1‐integrin‐mediated adhesion of melanoma cells to the propolypeptide of von Willebrand factor

Propolypeptide of von Willebrand Factor Is a Novel Ligand for Very Late Antigen-4 Integrin

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