| 1. |
- Mazzucato, M, et al.
(författare)
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Vascular PG-M/versican variants promote platelet adhesion at low shear rates and cooperate with collagens to induce aggregation
- 2002
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Ingår i: FASEB Journal. - 1530-6860. ; 16:14, s. 1903-1916
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Tidskriftsartikel (refereegranskat)abstract
- We have identified a novel von Willebrand factor/fibrinogen/selectin-independent, platelet adhesion-promoting function of vascular PG-M/versicans that may be relevant in normal venous thrombosis and critical in atherosclerotic conditions. A purification scheme was devised to obtain vascular versicans, which by biochemical, immunochemical, and ultrastructural means were asserted to be 1) composed primarily of isoforms V1 and V2; 2) free of contaminants; 3) prevalently substituted with chondroitin-4-sulfate and dermatan sulfate (DS) chains; and 4) capable of binding hyaluronan to form link protein-stabilized ternary complexes. Real-time analysis of human platelet perfused under diverse shear forces showed that they largely failed to bind to several vascular and nonvascular proteoglycans (PGs). In contrast, they bound in a dose- and shear rate-dependent manner to vascular versicans, exhibiting a unique attachment-detachment kinetics and establishing a firm substrate tethering characterized with no significant aggregation. Digestion of these PGs with lyases and competition experiments with purified glycosaminoglycans revealed that platelet adhesion to vascular versicans was primarily mediated by their DS chains. Incorporation of the versicans into fibrillar collagen substrates augmented their adhesive activity and strongly promoted platelet aggregation at low and high shear rates. Affinity chromatography of platelet surfaces on DS columns identified a 120-140 kDa polypeptide complex that behaved as a specific vascular versican binding membrane ligand in solid-phase binding assays. These findings indicate that selective versican variants of the subendothelium may serve as ancillary GPIbalpha/integrin/selectin-independent platelet ligands in healthy and diseased vascular beds and may be directly responsible for the platelet accruing after rupture of atherosclerotic plaques., versican variants promote platelet adhesion at low shear rates and cooperate with collagens to induce aggregation.
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| 2. |
- Cattaruzza, S, et al.
(författare)
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Distribution of PG-M/versican variants in human tissues and de novo expression of isoform V3 upon endothelial cell activation, migration, and neoangiogenesis in vitro
- 2002
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 277:49, s. 47626-47635
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Tidskriftsartikel (refereegranskat)abstract
- We have carried out a comprehensive molecular mapping of PG-M/versican isoforms V0-V3 in adult human tissues and have specifically investigated how the expression of these isoforms is regulated in endothelial cells in vitro. A survey of 21 representative tissues highlighted a prevalence of V1 mRNA, demonstrated that the relative frequency of expression was V1>V2>V3greater than or equal toV2; and showed that <15% of the tissues transcribed significant levels of all four isoforms. By employing novel and previously described anti-versican antibodies we verified a ubiquitous versican deposition in normal and tumor-associated vascular structures and disclosed differences in the glycanation profiles of versicans produced in different vascular beds. Resting endothelial cells isolated from different tissue sources transcribed several of the versican isoforms but consistently failed to translate these mRNAs into detectable proteoglycans. However, if stimulated with tumor necrosis factor-α or vascular endothelial growth factor, they altered their versican expression by de novo transcribing the V3 isoform and by exhibiting a moderate V1/V2 production. Induced versican synthesis and de novo V3 expression was also observed in endothelial cells elicited to migrate in a wound-healing model in vitro and in angiogenic endothelial cells forming tubule-like structures in Matrigel or fibrin clots. The results suggest that, independent of the degree of vascularization, human adult tissues show a limited expression of versican isoforms V0, V2, and V3 and that endothelial cells may contribute to the deposition of versican in vascular structures, but only following proper stimulation.
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| 3. |
- Kassner, A, et al.
(författare)
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Molecular structure and interaction of recombinant human type XVI collagen
- 2004
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Ingår i: Journal of Molecular Biology. - : Elsevier BV. - 1089-8638 .- 0022-2836. ; 339:4, s. 835-853
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Tidskriftsartikel (refereegranskat)abstract
- Collagen XVI is a minor component of at least two different extracellular fibrillar networks of specialized regions of skin and cartilage. In skin, collagen XVI is integrated into particular fibrillin-rich microfibrils lacking an amorphous elastin core. In cartilage, collagen XVI is a component of small heterotypic D-banded fibrils, mainly occurring in the territorial matrix of chondrocytes. Here, we present the first direct evidence for the molecular structure and functional properties of these fibril-associated collagens with interrupted triple helices (FACIT). We have expressed recombinantly the full-length alpha1 chain of human collagen XVI in HEK 293 EBNA cells in large quantities using an episomal expression system. Secreted full-length recombinant collagen XVI forms stable disulfide-bonded homotrimers and is rapidly proteolytically processed to distinct fragments at specific protease sequence motifs, one resembling an aggrecanase recognition site. Limited trypsin digestion assays and thermal transition curves imply sequential thermal denaturation of individual triple helical domains of this recombinant collagen, similar to authentic collagen XVI. Molecular images of collagen XVI reveal rod-like molecules which harbor multiple sharp kinks attributing a highly flexible structure presumably introduced by non-collagenous (NC) regions. Terminally located cloverleaf-shaped nodules correspond to the large NC NC11 domain of trimeric collagen XVI. The total length of individual trimeric recombinant collagen XVI molecules constitutes about 240 nm as calculated by atomic force and negative staining electron microscopy. Recombinant collagen XVI interacts with fibrillin-1 and with fibronectin indicating multiple molecular interactions in which this ubiquitously expressed and versatile FACIT-collagen can participate. In vitro generated collagen XVI provides an indispensable tool for future determination of its function during supramolecular assembly of matrix aggregates and its role in maintenance, organization and interaction of fibrillar structures. (C) 2004 Elsevier Ltd. All rights reserved.
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| 4. |
- Klatt, A R, et al.
(författare)
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Molecular structure and tissue distribution of matrilin-3, a filament-forming extracellular matrix protein expressed during skeletal development
- 2000
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 275:6, s. 3999-4006
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Tidskriftsartikel (refereegranskat)abstract
- Matrilin-3 is a recently identified member of the superfamily of proteins containing von Willebrand factor A-like domains and is able to form hetero-oligomers with matrilin-1 (cartilage matrix protein) via a C-terminal coiled-coil domain. Full-length matrilin-3 and a fragment lacking the assembly domain were expressed in 293-EBNA cells, purified, and subjected to biochemical characterization. Recombinantly expressed full-length matrilin-3 occurs as monomers, dimers, trimers, and tetramers, as detected by electron microscopy and SDS-polyacrylamide gel electrophoresis, whereas matrilin-3, purified from fetal calf cartilage, forms homotetramers as well as hetero-oligomers of variable stoichiometry with matrilin-1. In the matrix formed by cultured chondrosarcoma cells, matrilin-3 is found in a filamentous, collagen-dependent network connecting cells and in a collagen-independent pericellular network. Affinity-purified antibodies detect matrilin-3 expression in a variety of mouse cartilaginous tissues, such as sternum, articular, and epiphyseal cartilage, and in the cartilage anlage of developing bones. It is found both inside the lacunae and in the interterritorial matrix of the resting, proliferating, hypertrophic, and calcified cartilage zones, whereas the expression is lower in the superficial articular cartilage. In trachea and in costal cartilage of adult mice, an expression was seen in the perichondrium. Furthermore, matrilin-3 is found in bone, and its expression is, therefore, not restricted to chondroblasts and chondrocytes.
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| 5. |
- Perissinotto, D, et al.
(författare)
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Avian neural crest cell migration is diversely regulated by the two major hyaluronan-binding proteoglycans PG-M/versican and aggrecan
- 2000
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Ingår i: Development: For advances in developmental biology and stem cells. - 1477-9129. ; 127:13, s. 2823-2842
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Tidskriftsartikel (refereegranskat)abstract
- It has been proposed that hyaluronan-binding proteoglycans play an important role as guiding cues during neural crest (NC) cell migration, but their precise function has not been elucidated. In this study, we examine the distribution, structure and putative role of the two major hyaluronan-binding proteoglycans, PG-M/versicans and aggrecan, during the course of avian NC development. PG-M/versicans V0 and V1 are shown to be the prevalent isoforms at initial and advanced phases of NC cell movement, whereas the V2 and V3 transcripts are first detected following gangliogenesis. During NC cell dispersion, mRNAs for PG-M/versicans V0/V1 are transcribed by tissues lining the NC migratory pathways, as well as by tissues delimiting nonpermissive areas. Immunohistochemistry confirm the deposition of the macromolecules in these regions and highlight regional differences in the density of these proteoglycans. PG-M/versicans assembled within the sclerotome rearrange from an initially uniform distribution to a preferentially caudal localization, both at the mRNA and protein level. This reorganization is a direct consequence of the metameric NC cell migration through the rostral portion of the somites. As suggested by previous in situ hybridizations, aggrecan shows a virtually opposite distribution to PG-M/versicans being confined to the perinotochordal ECM and extending dorsolaterally in a segmentally organized manner eventually to the entire spinal cord at axial levels interspacing the ganglia. PG-M/versicans purified from the NC migratory routes are highly polydispersed, have an apparent M(r) of 1,200-2,000 kDa, are primarily substituted with chondroitin-6-sulfates and, upon chondroitinase ABC digestion, are found to be composed of core proteins with apparent M(r )of 360-530, 000. TEM/rotary shadowing analysis of the isolated PG-M/versicans confirmed that they exhibit the characteristic bi-globular shape, have core proteins with sizes predicted for the V0/V1 isoforms and carry relatively few extended glycosaminoglycan chains. Orthotopical implantation of PG-M/versicans immobilized onto transplantable micromembranes tend to 'attract' moving cells toward them, whereas similar implantations of a notochordal type-aggrecan retain both single and cohorts of moving NC cells in close proximity of the implant and thereby perturb their spatiotemporal migratory pattern. NC cells fail to migrate through three-dimensional collagen type I-aggrecan substrata in vitro, but locomote in a haptotactic manner through collagen type I-PG-M/versican V0 substrata via engagement of HNK-1 antigen-bearing cell surface components. The present data suggest that PG-M/versicans and notochordal aggrecan exert divergent guiding functions during NC cell dispersion, which are mediated by both their core proteins and glycosaminoglycan side chains and may involve 'haptotactic-like' motility phenomena. Whereas aggrecan defines strictly impenetrable embryonic areas, PG-M/versicans are central components of the NC migratory pathways favoring the directed movement of the cells.
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| 6. |
- Piecha, D, et al.
(författare)
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Matrilin-2 interacts with itself and with other extracellular matrix proteins
- 2002
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Ingår i: Biochemical Journal. - 0264-6021. ; 367:3, s. 715-721
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Tidskriftsartikel (refereegranskat)abstract
- Matrilin-2 is a component of extracellular filamentous networks. To study the interactions by which it can be integrated into such assemblies, full-length and truncated forms of matrilin-2 were recombinantly expressed in HEK-293 cells and purified from conditioned medium. The recombinant proteins, when used in interaction assays, showed affinity to matrilin-2 itself, but also to other collagenous and non-collagenous extracellular matrix proteins. The interaction between matrilin-2 and collagen I was studied in greater detail and could be shown to occur at distinct sites on the collagen I molecule and to have a K-D of about 3 x 10(-8) M. Interactions with some non-collagenous protein ligands were even stronger, with matrilin-2 binding to fibrillin-2, fibronectin and laminin-1-nidogen-1 complexes, with K-D values in the range of 10(-8)-10(-11) M. Co-localization of matrilin-2 with these ligands in the dermal-epidermal basement membrane, in the microfibrils extending from the basement membrane into the dermis, and in the dermal extracellular matrix, indicates a physiological relevance of the interactions in the assembly of supramolecular extracellular matrix structures.
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| 7. |
- Sengle, G, et al.
(författare)
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Identification and characterization of AMACO, a new member of the von Willebrand factor A-like domain protein superfamily with a regulated expression in the kidney
- 2003
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 278:50, s. 50240-50249
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Tidskriftsartikel (refereegranskat)abstract
- The genes coding for human and mouse AMACO, an extracellular matrix protein containing VWA-like domains related to those in MAtrilins and COllagens, were detected in databases, the cDNAs were cloned, and the primary structures were deduced from the nucleotide sequences. The genes consist of 14 exons and have a similar exon/intron organization. The protein consists of a signal peptide sequence, an N-terminal VWA domain connected to two additional, tandem VWA domains by a cysteine-rich sequence and an epidermal growth factor (EGF)-like domain. The C terminus is made up of another EGF-like domain followed by a unique sequence present in mouse, but absent in human. The predicted molecular weight of the proteins is 79,485 in human and 83,024 in mouse. Full-length AMACO was expressed in 293-EBNA cells, purified by use of an affinity tag and subjected to biochemical characterization. Both monomers and aggregates of AMACO were recovered, as shown by electron microscopy and SDS-PAGE. AMACO was found in the media of a variety of established cell lines of both fibroblast and epithelial origin. In the matrix formed by 293-EBNA cells overexpressing the protein, AMACO was deposited in patchy structures that were often cell-associated. Affinity-purified antibodies detect expression in cartilage and expression associated with certain basement membranes. In the kidney of adult mice, a second promoter located in intron 4 is active. If the resulting transcript is translated it could not yield a secreted protein because of the lack of a signal peptide sequence. The developmental switch from an AMACO mRNA, expressed by the newborn kidney, to the truncated transcript found in the adult kidney indicates an unusual regulation of AMACO expression.
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| 8. |
- Vynios, D H, et al.
(författare)
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Polydispersity and heterogeneity of squid cranial cartilage proteoglycans as assessed by immunochemical methods and electron microscopy
- 2000
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Ingår i: Biochimie. - 1638-6183. ; 82:8, s. 773-782
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Tidskriftsartikel (refereegranskat)abstract
- The three populations of squid cranial cartilage proteoglycans, D1D1A, D1D1B and D1D2 appeared to have a high degree of polydispersity. Gel electrophoresis and immunoblotting analysis showed that polydispersity was mainly due to the variable size of chondroitin sulphate E chains. This was further ascertained after rotary shadowing electron microscopy of proteoglycan core proteins and glycosaminoglycan side chains and statistical analysis of the sizes measured for both components. Enzymic treatment of the proteoglycan core proteins produced different peptides from each population, suggesting that the observed heterogeneity of the proteoglycans is due to their core proteins. Antibodies were raised in rabbits against all proteoglycans and enzyme-linked immunosorbent analysis of proteoglycan core proteins revealed that the proteoglycans, even heterogeneous, shared many common epitopes. Part of the common proteoglycan epitopes were found to be located in chondroitin sulphate E chains. Heterogeneity of squid proteoglycans was also investigated by studying their interactions with collagen and it was found that only the two populations of high molecular mass, D1D1A and D1D2, were able to interact with only collagen type I, the latter stronger than the former.
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| 9. |
- Werthen, M, et al.
(författare)
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Pseudomonas aeruginosa-induced infection and degradation of human wound fluid and skin proteins ex vivo are eradicated by a synthetic cationic polymer
- 2004
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Ingår i: Journal of Antimicrobial Chemotherapy. - : Oxford University Press (OUP). - 1460-2091 .- 0305-7453. ; 54:4, s. 772-779
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Antimicrobial peptides are important effectors of innate immunity. Bacteria display multiple defence mechanisms against these peptides. For example, Pseudomonas aeruginosa releases potent proteinases that inactivate the human cathelicidin LL-37. Hence, in conditions characterized by persistent bacterial colonization, such as in P. aeruginosa-infected skin wounds, there is a need for efficient means of reducing bacterial load. Here, the effect of the cationic molecule polyhexamethylenebiguanide (PHMB) was evaluated. Methods: Infection models in human wound fluid and human skin were established. Radial diffusion methods, bacterial growth and bactericidal assays were used for determination of effects of PHMB on bacteria in the presence of plasma, wound fluid or human skin. At the protein and tissue levels, SDS-PAGE, light microscopy and scanning electron microscopy were used to study the effects of P. aeruginosa infection before and after addition of PHMB. Results: PHMB killed common ulcer-derived bacteria in the presence of human wound fluid. Furthermore, elastase-expressing P. aeruginosa completely degraded wound fluid proteins as well as human skin during infection ex vivo. The infection, and consequent protein degradation, was reversed by PHMB. Conclusions: The ex vivo infection models presented here should be helpful in the screening of novel antimicrobials and constitute a prerequisite for future clinical studies.
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| 10. |
- Yingsung, W, et al.
(författare)
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Molecular heterogeneity of the SHAP-hyaluronan complex - Isolation and characterization of the complex in synovial fluid from patients with rheumatoid arthritis
- 2003
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 278:35, s. 32710-32718
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Tidskriftsartikel (refereegranskat)abstract
- We previously found that a covalent complex of SHAPs (serum-derived hyaluronan-associated proteins), the heavy chains of inter-alpha-trypsin inhibitor family molecules, with hyaluronan ( HA) is accumulated in synovial fluid of patients with rheumatoid arthritis, and the complex is circulated in patient plasma at high concentrations. How the SHAP-HA complex participates in this disease is unknown. To address this question, it is essential to clarify the structural features of this macromolecule. The SHAP-HA complex purified from synovial fluid of the patients by three sequential CsCl isopycnic centrifugations was heterogeneous in density, and the fractions with different densities had distinct SHAP-to-HA ratios. Agarose gel electrophoresis and column chromatography revealed that there was no apparent difference in the size distribution of HA to which SHAPs were bound between the fractions with different densities. The SHAP-HA complex in the higher density fraction had fewer SHAP molecules per HA chain. Therefore, the difference between the fractions with different densities was due to a heterogeneous population of the SHAP-HA complex, namely the different number of SHAP molecules bound to an HA chain. Based on the SHAP and HA contents of the purified preparations, we estimated that an HA chain with a molecular weight of 2 x 10(6) has as many as five covalently bound SHAPs, which could give a proteinaceous multivalency to HA. Furthermore, we also found that the SHAP-HA complex tends to form aggregates, judging from the migration and elution profiles in agarose gel electrophoresis and gel filtration, respectively. The multivalent feature of the SHAP-HA complex was also confirmed by the negative staining electron micrographic images of the purified fractions. Taken together, those structural characteristics may underlie the aggregate-forming and extracellular matrix-stabilizing ability of the SHAP-HA complex.
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