scholarly journals Platelet-reactive sites in collagens type I and type III. Evidence for separate adhesion and aggregatory sites

1989 ◽  
Vol 258 (1) ◽  
pp. 157-163 ◽  
Author(s):  
L F Morton ◽  
A R Peachey ◽  
M J Barnes
Keyword(s):  
Platelet Adhesion ◽  
Collagen Type ◽  
Background Level ◽  
Collagen Type I ◽  
Human Platelets ◽  
Collagen Molecule ◽  
Rabbit Platelet ◽  
Type I ◽  
Variable Degree ◽  
Type V

The adhesion of human and rabbit platelets to collagens and collagen-derived fragments immobilized on plastic was investigated. Adhesion appeared to be independent of collagen conformation, since similar attachment occurred to collagen (type I) in monomeric form, as fibres or in denatured state. The adhesion of human platelets was stimulated to a variable degree by Mg2+, but rabbit platelet adhesion showed little if any dependence on this cation. Collagens type I, III, V and VI were all able to support adhesion, although that to collagen type V (native) was lower than that to the other collagens. Adhesion to a series of peptides derived from collagens I and III was measured. Attachment did not require the presence of peptides in triple-helical configuration. The extent of adhesion ranged from relatively high, as good as to the intact parent collagen molecule, to little if any adhesive activity beyond the non-specific (background) level. The existence of very different degrees of activity suggests that platelet adhesion is associated with specific structural sites in the collagen molecule. Adhesion in many instances was essentially in accord with the known platelet-aggregatory activity of individual peptides. However, two peptides, alpha 1(I)CB3 and alpha 1(III)CB1,8,10,2, exhibited good adhesive activity although possessing little if any aggregatory activity. Of particular interest, despite its near-total lack of aggregatory activity, adhesion to peptide alpha 1(I)CB3 was as good as that to the structurally homologous peptide alpha 1(III)CB4, in which is located a highly reactive aggregatory site. This implies that platelet adhesion to collagen may involve sites in the collagen molecule distinct from those more directly associated with aggregation.

scholarly journals Collagen type I and type V are present in the same fibril in the avian corneal stroma.

1988 ◽  
Vol 106 (3) ◽  
pp. 999-1008 ◽  
Author(s):  
D E Birk ◽  
J M Fitch ◽  
J P Babiarz ◽  
T F Linsenmayer
Keyword(s):  
Monoclonal Antibodies ◽  
Collagen Type ◽  
Corneal Stroma ◽  
Collagen Type I ◽  
Collagen Molecule ◽  
Type I ◽  
Collagen Types ◽  
Type V Collagen ◽  
Fibril Structure ◽  
Type V

The distribution, supramolecular form, and arrangement of collagen types I and V in the chicken embryo corneal stroma were studied using electron microscopy, collagen type-specific monoclonal antibodies, and a preembedding immunogold method. Double-label immunoelectron microscopy with colloidal gold-tagged monoclonal antibodies was used to simultaneously localize collagen type I and type V within the chick corneal stroma. The results definitively demonstrate, for the first time, that both collagens are codistributed within the same fibril. Type I collagen was localized to striated fibrils throughout the corneal stroma homogeneously. Type V collagen could be localized only after pretreatment of the tissue to partially disrupt collagen fibril structure. After such pretreatments the type V collagen was found in regions where fibrils were partially dissociated and not in regions where fibril structure was intact. When pretreated tissues were double labeled with antibodies against types I and V collagen coupled to different size gold particles, the two collagens colocalized in areas where fibril structure was partially disrupted. Antibodies against type IV collagen were used as a control and were nonreactive with fibrils. These results indicate that collagen types I and V are assembled together within single fibrils in the corneal stroma such that the interaction of these collagen types within heterotypic fibrils masks the epitopes on the type V collagen molecule. One consequence of the formation of such heterotypic fibrils may be the regulation of corneal fibril diameter, a condition essential for corneal transparency.

scholarly journals Relative rates of biosynthesis of collagen type I, type V and type VI in calf cornea

1991 ◽  
Vol 274 (2) ◽  
pp. 615-617 ◽  
Author(s):  
P Kern ◽  
M Menasche ◽  
L Robert
Keyword(s):  
Type I Collagen ◽  
Collagen Type ◽  
Corneal Stroma ◽  
Collagen Type I ◽  
Type I ◽  
Type Vi Collagen ◽  
Sds Page ◽  
Proline Incorporation ◽  
Type V

The biosynthesis of type I, type V and type VI collagens was studied by incubation of calf corneas in vitro with [3H]proline as a marker. Pepsin-solubilized collagen types were isolated by salt fractionation and quantified by SDS/PAGE. Expressed as proportions of the total hydroxyproline solubilized, corneal stroma comprised 75% type I, 8% type V and 17% type VI collagen. The rates of [3H]proline incorporation, linear up to 24 h for each collagen type, were highest for type VI collagen and lowest for type I collagen. From pulse-chase experiments, the calculated apparent half-lives for types I, V and VI collagens were 36 h, 10 h and 6 h respectively.

PRIMARY BINDING SITE OF VON WILLEBRAND FACTOR IN THE SUBENDOTHELIUM WHICH MEDIATES PLATELET ADHESION IS NOT COLLAGEN

1987 ◽  
Author(s):  
Philip G de Groot ◽  
Jan A van Mourik ◽  
Jan J Sixma
Keyword(s):  
Monoclonal Antibody ◽  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Collagen Type I ◽  
Extracellular Matrices ◽  
Type I ◽  
Type Iii ◽  
Von Willebrand ◽  
Willebrand Factor

We have studies the binding of von Willebrand factor (vWF) to extracellular matrices of endothelial cells and smooth muscle cells and to the vessel wall of human umbilical arteries in relation to its function in supporting platelet adhesion at high shear rates. CLB-RAg 38, a monoclonal antibody directed against vWF inhibits the binding of 125I-vWF extracellular matrices completely. The binding of 125I-vWF to subendothelium is not inhibited, because there are many different binding sites. CLB-RAg 38 inhibits platelet adhesion to extracellular matrices and subendothelium, in sofar as it is dependent on plasma vWF. CLB-RAg 38 has no effect on adhesion depending on vWF already bound to the matrix or subendothelium. CLB-RAg 38 does not inhibit binding of vWF to collagen type I and type III. Another monoclonal antibody against vWF, CLB-RAg 201, completely inhibits binding of vWF to collagen type I and type III. CLB-RAg 201 does not inhibit binding of 125I-vWF ot the extracellular matrices. CLB-RAg 201 partly inhibits platelet adhesion but this inhibition is also present when the adhesion depends on vWF already present in matrix or subendothelium, indicating that CLB-RAg 201 also inhibits the adhesion of platelets directly, this in contrast to CLB-RAg 38. The epitopes for CLB-RAg 201 and 38 were found on different tryptic fragments of vWF. These data indicate that vWF binds to subendothelium and to matrices of cultured cells by mechanism that is different from binding to collagen.

scholarly journals Immunoelectron microscopic localization of collagens type I, V, VI and of procollagen type III in human periodontal ligament and cementum.

1991 ◽  
Vol 39 (1) ◽  
pp. 103-110 ◽  
Author(s):  
J Becker ◽  
D Schuppan ◽  
J P Rabanus ◽  
R Rauch ◽  
U Niechoy ◽  
...  
Keyword(s):  
Periodontal Ligament ◽  
Collagen Type ◽  
Ultrastructural Localization ◽  
Collagen Type I ◽  
Collagen Fibrils ◽  
Type I ◽  
Type Iii ◽  
Procollagen Type ◽  
Collagen Type Vi ◽  
Type V

We examined the ultrastructural localization of collagens Type I, V, VI and of procollagen Type III in decalcified and prefixed specimens of the periodontal ligament and cementum, by immunoelectron microscopy using ultra-thin cryostat sections. Immunostaining for collagen Type I was pronounced on the major cross-striated fibrils entering cementum and in cementum proper, whereas staining for procollagen Type III was almost exclusively observed on the major fibrils in the periodontal ligament situated more remote from cementum. Reactivity for collagen Type V was limited to aggregated, unbanded filamentous material of about 12 nm diameter that was found mainly in larger spaces between bundles of cross-striated collagen fibrils and occasionally on single microfibrils that apparently originated from the ends of the major collagen fibrils, which may support the concept of this collagen as a component of core fibrils. Collagen Type VI was present as microfilaments appearing to interconnect single cross-striated fibrils. In the densely packed fibril bundles of the periodontal ligament, no collagen type VI was detected. Neither Type V or Type VI collagen was observed in cementum.

scholarly journals Morphological features and the functional state of connective tissue of the uterine rudiments in reproductive age patients with Mayer–Rokitansky–Küster–Hauser syndrome

2020 ◽  
Vol 9 (4) ◽  
pp. 24-30
Author(s):  
A.V. Asaturova ◽  
◽  
N.M. Faizullina ◽  
M.V. Bobkova ◽  
A.S. Arakelyan ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Collagen Type ◽  
Tissue Remodeling ◽  
Collagen Type I ◽  
Morphological Features ◽  
Control Group ◽  
Type I ◽  
Variable Degree ◽  
Collagen Iii ◽  
Connective Tissue Remodeling

Introduction. Female patients with Mayer–Rokitansky–Küster–Hauser syndrome (MRKH) have high stigma scores; the condition severely affects the reproductive system. The study aimed at specification of morphological features and assessment of the maturity of connective tissues of the uterine rudiments in MRKH. Patients and methods. The study included 42 patients with vaginal and uterine aplasia having functioning uterine rudiments and 47 patients of the control group without genital malformations. Age of the patients was 20-24 years in 67.2% of the cases, and 31.2% of the patients were aged ≤ 19, inclusive. Immunohistochemi-cal assay was applied to determine expression levels of collagen I, collagen III, ММР2, ММР9, TIMP1, fibronectin and laminin proteins within the functioning uterine rudiments in comparison with levels of the same proteins in normally developed uterine tissues. Results. Decreased expression of collagen type I and elevated levels of MMP2 and MMP9 proteins in uterine tissues were observed for the group of patients with MRKH. Conclusions. 1) Uterine rudiments in patients with MRKH show variable degree of morphological similarity with the normally developed uterus; 2) The functioning uterine rudiments are subject to the same pathological processes as the normally developed uterus (myoma, endometriosis). 3) The functioning uterine rudiments in patients with MRKH show altered patterns of connective tissue remodeling, with decreased expression of collagen type I and increased expression of matrix metalloproteinases MMP2 and MMP9. Keywords: Müllerian aplasia, uterine rudiments, metalloproteinases, connective tissue remodeling, ММР2, ММР9

Platelet Collagen Activation by Basement Membrane Collagens

1979 ◽  
Author(s):  
L. Balleisen ◽  
J. Rauterberg
Keyword(s):  
Basement Membrane ◽  
Collagen Type ◽  
Normal Subjects ◽  
Collagen Type I ◽  
Short Chain ◽  
Collagen Type Iv ◽  
Type I ◽  
Type Iv ◽  
Aggregation Activity ◽  
Type V

The collagen component of the vessel intima consists of collagen type I, III and basement membrane collagens. For type III a particularly potent platelet aggregation activity was found earlier.Three different basement membrane collagens were isolated from call placenta. Occurence of type IV and V(A/B collagen) in the intimal and medial layer of vessel walls has been shown by chemical and immunhistological means(1). The third basement membrane collagen is probably isentical with the 55000 molecular weight component described by CHUNG et al. (2).Platelets from normal subjects were tested for aggregation and spreading on Zaponlack with type IV, V, the separated A and B chains of type V and the short chain collagen. Complete aggregation was obtained only with native type V collagen. Spreading of platelets was induced only by collagen type IV, the A chain of type V and the short chain collagen.The data indicate that all basement membrane collagens activate platelets but in different respects.1. Rauterberg J. et al.: Coll. Int. Cent. Nat. Rech. Sc. 287:220(1978)2. Chung E. et al.: Bioehem. Biophys. Res. Comm. 71: 1167(1976)

Improved separation of alpha chains of collagen type I, type III, and type V by noninterrupted electrophoresis using thioglycolic acid as a negatively charged reducer

1989 ◽  
Vol 10 (1) ◽  
pp. 29-33 ◽  
Author(s):  
Kazuyuki Nakamura ◽  
Shin-Ichi Inoue ◽  
Seishou Abiko ◽  
Hideo Aoki ◽  
Kazusuke Takeo
Keyword(s):  
Collagen Type ◽  
Thioglycolic Acid ◽  
Collagen Type I ◽  
Type I ◽  
Type Iii ◽  
Type V

scholarly journals An echistatin C-terminal peptide activates GPIIbIIIa binding to fibrinogen, fibronectin, vitronectin and collagen type I and type IV

1993 ◽  
Vol 293 (1) ◽  
pp. 263-267 ◽  
Author(s):  
P S Wright ◽  
V Saudek ◽  
T J Owen ◽  
S L Harbeson ◽  
A J Bitonti
Keyword(s):  
Protein Interactions ◽  
Collagen Type ◽  
Collagen Type I ◽  
Human Platelets ◽  
Type I ◽  
Venom Protein ◽  
Type Iv ◽  
Fibrinogen Binding ◽  
Additional Protein ◽  
Integrin Ligand

Integrin binding to proteins often involves recognition of domains containing the arginine-glycine-aspartate (RGD) motif. Different binding affinities and specificities of the integrin-ligand protein interactions involve additional protein domains. The n.m.r. structure of the snake-venom protein echistatin suggested that the C-terminal portion of the molecule might be important, in addition to the RGD domain, in binding to the integrin glycoprotein IIbIIIa (GPIIbIIIa) [Saudek, Atkinson and Pelton (1991) Biochem. 30, 7369-7372]. The synthetic C-terminal peptide, echistatin-(40-49), PRNPHKGPAT, (1) inhibited binding of GPIIbIIIa to immobilized echistatin (IC50 3-6 mM), but did not inhibit binding of GPIIbIIIa to immobilized fibrinogen (up to 5 mM peptide), (2) activated GPIIbIIIa binding to fibronectin and vitronectin, usual ligands for the activated integrin, (3) activated binding of GPIIbIIIa to collagen type I and type IV, proteins not usually regarded as ligands for the integrin, and (4) stimulated 125I-fibrinogen binding by human platelets. These findings argue for an interaction of this non-RGD domain in echistatin with GPIIbIIIa, leading to activation of the integrin and extension of the ligand specificity to include immobilized collagen.

Reduced Platelet Adhesion for Blended Electrospun Meshes with Low Amounts of Collagen Type I

2021 ◽  
pp. 2100267
Author(s):  
Mahyar Sameti ◽  
Kai Clarke ◽  
Prerona Dewan ◽  
Kenyatta S. Washington ◽  
Somayeh Talebzadeh ◽  
...  
Keyword(s):  
Platelet Adhesion ◽  
Collagen Type ◽  
Collagen Type I ◽  
Type I

The Development of Small Molecule Inhibitors of Collagen Binding to the Integrin α2β1 as Antithrombotic Drugs.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3677-3677
Author(s):  
Sungwook Choi ◽  
Seth E. Snyder ◽  
David T. Moore ◽  
Gaston Vilaire ◽  
Joel S. Bennett ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Small Molecule ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Small Molecule Inhibitors ◽  
Collagen Type I ◽  
Mouse Tumor ◽  
Type I ◽  
Immunoglobulin Gene ◽  
Collagen Binding

Abstract Platelets tether to collagen in the subendothelial matrix that is exposed by vascular damage. Collagen is a particularly important matrix component in this context, not only because it is a substrate for platelet adhesion, but because it is an agonist for platelet aggregation and secretion as well. There are two platelet collagen receptors, the immunoglobulin gene superfamily member GPVI and the integrin α2Β1. Both are involved in adhesion to exposed collagen and generate downstream activating signals. α2Β1 is widely expressed and has been implicated in hemostasis and thrombosis, as well as cancer metastasis, wound healing, and angiogenesis. In mice, α2Β1 deficiency results in decreased ex vivo platelet aggregation, but normal bleeding times. In mouse tumor models, α2Β1 blockade reduces both metastasis and angiogenesis. Humans lacking α2Β1 have a mild bleeding diathesis. Given this background, α2Β1 appears to be an appropriate target for the development of small-molecule inhibitors to serve as relatively safe anti-platelet and anti-tumor agents, either acting alone or in synergy with other anti-platelet or anti-tumor agents. We have developed two classes of small-molecule α2Β1 inhibitors. The first class is targeted against the collagen binding site located on the α2 I-domain and was designed using molecular modeling to superimpose a dipeptide scaffold onto the published crystal structure of the I-domain bound to a collagen-mimetic peptide (GFOGER). These molecules block recombinant human I-domain binding to immobilized collagen type I with IC50s as low as 10 μM. Although the molecules inhibit platelet adhesion to collagen only at higher concentrations, they readily inhibit melanoma cell adhesion to collagen mimetics. It is also noteworthy that the molecules induce platelet protein phosphorylation and potentiate platelet aggregation induced by other platelet agonists, both of which can be prevented by pre-incubating platelets with monoclonal antibodies directed against the α2 I-domain, but not against GPVI. The second class of molecules was derived from proline-substituted 2,3-diaminopropionic acids and is directed against the Β1 I-like domain, an allosteric site that regulates ligand binding. These molecules are potent inhibitors of platelet adhesion to immobilized soluble collagen type I with IC50s of 10–50 nM and inhibit the adhesion of melanoma cells to collagen mimetics with IC50s of 250–350 nM. These molecules do not inhibit platelet aggregation, nor do they inhibit I-domain binding to immobilized collagen type I, behavior consistent with binding to the Β1 I-like domain. In a murine model of ferric-chloride induced carotid thrombosis, the molecules synergize with aspirin to prevent arterial thrombosis. In summary, we have developed two classes of small molecule inhibitors that impair the interaction of collagen with the integrin α2Β1. Although both classes of inhibitors bind to α2Β1, their effects on its function are substantially different, indicating that there are multiple potential strategies for inhibiting integrin function pharmacologically. Further development of these inhibitors may lead to agents that will be clinically useful in the treatment of thrombosis and cancer.

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