scholarly journals Type VI collagen and glycoprotein MFPI are distinct components of the extracellular matrix

1986 ◽  
Vol 236 (1) ◽  
pp. 299-302 ◽  
Author(s):  
S Ayad ◽  
C A Chambers ◽  
L Berry ◽  
C A Shuttleworth ◽  
M E Grant
Keyword(s):  
Extracellular Matrix ◽  
Physicochemical Characteristics ◽  
Type Vi Collagen ◽  
Cultured Fibroblasts

Two collagenous glycoproteins, Mr 140,000 and Mr 150,000, are synthesized and secreted into the medium of cultured fibroblasts. The glycoprotein of Mr 140,000 is identical with the 140K(VI) component of type VI collagen by both immunological and physicochemical criteria. The glycoprotein of Mr 150,000 is immunologically distinct and exhibits the physicochemical characteristics of the putative elastic microfibrillar glycoprotein MFPI.

scholarly journals Molecular assembly, secretion, and matrix deposition of type VI collagen.

1986 ◽  
Vol 102 (3) ◽  
pp. 703-710 ◽  
Author(s):  
E Engvall ◽  
H Hessle ◽  
G Klier
Keyword(s):  
Extracellular Matrix ◽  
Culture Media ◽  
Molecular Assembly ◽  
Collagen Molecule ◽  
Type Vi Collagen ◽  
Cultured Fibroblasts ◽  
Intracellular Pool ◽  
Matrix Deposition ◽  
The Matrix ◽  
Tissue Form

Monoclonal antibodies reactive with the tissue form of type VI collagen were used to isolate the type VI collagen polypeptides from cultured fibroblasts and muscle cells. Two [35S]methionine-labeled polypeptides of 260 and 140 kD were found intracellularly, in the medium, and in the extracellular matrix of metabolically labeled cells. These polypeptides were disulfide cross-linked into very large complexes. The 260- and 140-kD polypeptides were intimately associated and could not be separated from each other by reduction without denaturation. In the absence of ascorbic acid, both polypeptides accumulated inside the cell, and their amounts in the medium and in the matrix were decreased. These results suggest that both the 260- and the 140-kD polypeptides are integral parts of the type VI collagen molecule. Examination of type VI collagen isolated from the intracellular pool by electron microscopy after rotary shadowing revealed structures corresponding to different stages of assembly of type VI collagen. Based on these images, a sequence for the intracellular assembly of type VI collagen could be discerned. Type VI collagen monomers are approximately 125 nm long and are composed of two globules separated by a thin strand. The monomers assemble into dimers and tetramers by lateral association. Only tetramers were present in culture media, whereas both tetramers and multimers were found in extracellular matrix extracts. The multimers appeared to have assembled from tetramers by end-to-end association into filaments that had prominent knobs and a periodicity of approximately 110 nm. These results show that, unlike other collagens, type VI collagen is assembled into tetramers before it is secreted from the cells, and they also suggest an extracellular aggregation mechanism that appears to be unique to this collagen.

Chondrons from articular cartilage. V. Immunohistochemical evaluation of type VI collagen organisation in isolated chondrons by light, confocal and electron microscopy

1992 ◽  
Vol 103 (4) ◽  
pp. 1101-1110 ◽  
Author(s):  
C.A. Poole ◽  
S. Ayad ◽  
R.T. Gilbert
Keyword(s):  
Electron Microscopy ◽  
Extracellular Matrix ◽  
Articular Cartilage ◽  
Specific Cell ◽  
Potential Contribution ◽  
Collagen Network ◽  
Tail Region ◽  
Type Vi Collagen ◽  
Surface Receptors ◽  
Basal Pole

The pericellular microenvironment around articular cartilage chondrocytes must play a key role in regulating the interaction between the cell and its extracellular matrix. The potential contribution of type VI collagen to this interaction was investigated in this study using isolated canine tibial chondrons embedded in agarose monolayers. The immunohistochemical distribution of an anti-type VI collagen antibody was assessed in these preparations using fluorescence, peroxidase and gold particle probes in combination with light, confocal and transmission electron microscopy. Light and confocal microscopy both showed type VI collagen concentrated in the pericellular capsule and matrix around the chondrocyte with reduced staining in the tail region and the interconnecting segments between adjacent chondrons. Minimal staining was recorded in the territorial and interterritorial matrices. At higher resolution, type VI collagen appeared both as microfibrils and as amorphous deposits that accumulated at the junction of intersecting capsular fibres and microfibrils. Electron microscopy also showed type VI collagen anchored to the chondrocyte membrane at the articular pole of the pericellular capsule and tethered to the radial collagen network through the tail at the basal pole of the capsule. We suggest that type VI collagen plays a dual role in the maintenance of chondron integrity. First, it could bind to the radial collagen network and stabilise the collagens, proteoglycans and glycoproteins of the pericellular microenvironment. Secondly, specific cell surface receptors exist, which could mediate the interaction between the chondrocyte and type VI collagen, providing firm anchorage and signalling potentials between the pericellular matrix and the cell nucleus. In this way type VI collagen could provide a close functional interrelationship between the chondrocyte, its pericellular microenvironment and the load bearing extracellular matrix of adult articular cartilage.

scholarly journals Induction of fibronectin matrix assembly in human fibrosarcoma cells by dexamethasone.

1987 ◽  
Vol 104 (3) ◽  
pp. 601-610 ◽  
Author(s):  
P J McKeown-Longo ◽  
C A Etzler
Keyword(s):  
Extracellular Matrix ◽  
Surface Protein ◽  
Order Rate Constant ◽  
Binding Activity ◽  
Matrix Assembly ◽  
Cultured Fibroblasts ◽  
Fibrosarcoma Cells ◽  
The Matrix ◽  
Fibronectin Binding ◽  
Human Fibrosarcoma Cells

Previous studies have suggested that the assembly of fibronectin into the extracellular matrix of cultured fibroblasts is mediated by specific matrix assembly receptors that recognize a binding site in the amino terminus of the fibronectin molecule (McKeown-Longo, P.J., and D.F. Mosher, 1985, J. Cell Biol., 100:364-374). In the presence of dexamethasone, human fibrosarcoma cells (HT-1080) acquired the ability to specifically bind exogenous plasma fibronectin and incorporate it into a detergent-insoluble extracellular matrix. Dexamethasone-induced fibronectin binding to HT-1080 cells was time dependent, dose dependent, and inhibited by cycloheximide. Saturation binding curves indicated that dexamethasone induced the appearance of 7.7 X 10(4) matrix assembly receptors per cell. The induced receptors exhibited a dissociation constant (KD) for soluble fibronectin of 5.0 X 10(-8) M. In parallel experiments, normal fibroblasts exhibited 4.1 X 10(5) receptors (KD = 5.3 X 10(-8) M) per cell. In the presence of cycloheximide, the induced fibronectin-binding activity on HT-1080 cells returned to uninduced levels within 12 h. In contrast, fibronectin-binding activity on normal fibroblasts was stable in the presence of cycloheximide for up to 54 h. The first-order rate constant (Kt = 2.07 X 10(-4) min-1) for the transfer of receptor-bound fibronectin to extracellular matrix was four- to fivefold less than that for normal fibroblasts (Kt = 1.32 X 10(-3) min-1). Lactoperoxidase-catalyzed iodination of HT-1080 monolayers indicated that a 48,000-mol-wt cell surface protein was enhanced with dexamethasone. The results from these experiments suggest that dexamethasone induces functional matrix assembly receptors on the surface of HT-1080 cells; however, the rate of incorporation of fibronectin into the matrix is much slower than that of normal fibroblasts.

Zonal Poisson Effect on the Chondron Deformation in Articular Cartilage under Compression

2007 ◽  
Vol 342-343 ◽  
pp. 133-136
Author(s):  
Jae Bong Choi
Keyword(s):  
Extracellular Matrix ◽  
Articular Cartilage ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Pericellular Matrix ◽  
Poisson Effect ◽  
Type Vi Collagen ◽  
Confocal Images ◽  
Three Dimensional Models

The objective of this study was to quantify the zonal difference of the in situ chondron’s Poisson effect under different magnitudes of compression. Fluorescence immunolabeling for type VI collagen was used to identify the pericellular matrix (PCM) and chondron, and a series of fluorescent confocal images were recorded and reconstructed to form quantitative three-dimensional models. The zonal variations in the mechanical response of the chondron do not appear to be due to zonal differences in PCM properties, but rather seem to result from significant inhomogeneities in relative stiffnesses of the extracellular matrix (ECM) and PCM with depth.

scholarly journals Binding and degradation of platelet thrombospondin by cultured fibroblasts.

1984 ◽  
Vol 98 (1) ◽  
pp. 22-28 ◽  
Author(s):  
P J McKeown-Longo ◽  
R Hanning ◽  
D F Mosher
Keyword(s):  
Extracellular Matrix ◽  
Cell Layer ◽  
Extracellular Fluid ◽  
Human Platelets ◽  
Lung Fibroblasts ◽  
Human Embryonic Lung ◽  
Cultured Fibroblasts ◽  
The Matrix ◽  
Specific Receptors ◽  
Or Organization

Thrombospondin was purified from human platelets and labeled with 125I, and its metabolism was quantified in cell cultures of human embryonic lung fibroblasts. 125I-Thrombospondin bound to the cell layer. The binding reached an apparent steady state within 45 min. Trichloroacetic acid-soluble radioactivity was detected in the medium after 30 min of incubation; the rate of degradation of 125I-thrombospondin was linear for several hours thereafter. Degradation of 125I-thrombospondin was saturable. The apparent Km and Vmax for degradation at 37 degrees C were 6 X 10(-8) M and 1.4 X 10(5) molecules per cell per minute, respectively. Degradation was inhibited by chloroquine or by lowering the temperature to 4 degrees C. Experiments in which cultures were incubated with thrombospondin for 45 min and then incubated in medium containing no thrombospondin revealed two fractions of bound thrombospondin. One fraction was localized by indirect immunofluorescence to punctate structures; these structures were lost coincident with the rapid degradation of 50-80% of bound 125I-thrombospondin. The second fraction was localized to a trypsin-sensitive, fibrillar, extracellular matrix. 125I-Thrombospondin in the matrix was slowly degraded over a period of hours. Binding of 125I-thrombospondin to the extracellular matrix was not saturable and indeed was enhanced at thrombospondin concentrations greater than 3 X 10(-8) M. The ability of 125I-thrombospondin to bind to extracellular matrix was diminished tenfold by limited proteolytic cleavage with trypsin. Degradation of trypsinized 125I-thrombospondin was also diminished, although to a lesser extent than matrix binding. Heparin inhibited both degradation and matrix binding. These results suggest that thrombospondin may play a transitory role in matrix formation and/or organization and that specific receptors on the cell surface are responsible for the selective removal of thrombospondin from the extracellular fluid and matrix.

scholarly journals Trends in the Development of Tailored Elastin-Like Recombinamer–Based Porous Biomaterials for Soft and Hard Tissue Applications

2021 ◽  
Vol 7 ◽  
Author(s):  
Lubinda Mbundi ◽  
Miguel González-Pérez ◽  
Fernando González-Pérez ◽  
Diana Juanes-Gusano ◽  
José Carlos Rodríguez-Cabello
Keyword(s):  
Extracellular Matrix ◽  
Biomedical Applications ◽  
Physicochemical Characteristics ◽  
Matrix Composition ◽  
Natural Polymers ◽  
Hard Tissue ◽  
Modular Assembly ◽  
Cell Compartmentalization ◽  
Porous Biomaterials ◽  
Synthetic And Natural Polymers

Porous biomaterials are of significant interest in a variety of biomedical applications as they enable the diffusion of nutrients and gases as well as the removal of metabolic waste from implants. Pores also provide 3D spaces for cell compartmentalization and the development of complex structures such as vasculature and the extracellular matrix. Given the variation in the extracellular matrix composition across and within different tissues, it is necessary to tailor the physicochemical characteristics of biomaterials and or surfaces thereof for optimal bespoke applications. In this regard, different synthetic and natural polymers have seen increased usage in the development of biomaterials and surface coatings; among them, elastin-like polypeptides and their recombinant derivatives have received increased advocacy. The modular assembly of these molecules, which can be controlled at a molecular level, presents a flexible platform for the endowment of bespoke biomaterial properties. In this review, various elastin-like recombinamer–based porous biomaterials for both soft and hard tissue applications are discussed and their current and future applications evaluated.

scholarly journals The influence of peptide bioregulators on skin aging in 3D culture model

2016 ◽  
Vol 19 (1) ◽  
pp. 58-63 ◽  
Author(s):  
K. V Kozhina ◽  
E. N Volkova ◽  
I. N Saburina ◽  
Sergey G. Morozov ◽  
I. M Zurina ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Matrix Protein ◽  
3D Culture ◽  
Dermal Fibroblasts ◽  
Extracellular Matrix Protein ◽  
Cytokeratin 19 ◽  
Collagen Type Iv ◽  
Cultured Fibroblasts ◽  
Study Results ◽  
Extracellular Matrix Components

He effect of mesotherapy injection (Meso-Wharton R199TM) on the dermal fibroblasts culture, simulating condition of (mature) aging skin cells are studied. Material and methods. The culture of 4th passage fibroblasts (P4), that corresponds to young skin fibroblasts (control) and the culture of 18th passage fibroblasts (P18), that has all the signs of aging dermal fibroblasts (predominance of large cells, slow cell division) were used. Bioactivity was assessed by cell morphology, epithelium-mesenchyme plasticity and expression of fibroblasts markers: cytokeratin 19, elastin, a-smooth muscle actin (aSMA), PCNA (proliferation marker), collagen types I, III, IV and fibronectin. The formation of spheroids occur when fibroblasts P18 are cultivating with the injection medication, on terms comparable to the formation of spheroids from P4 young fibroblasts. From culture of fibroblasts P18, that was cultured without medication, does not form the full spheroid, but aggregation of cells and their gradual destruction with necrotic masses within the unit are observed. The presence of the medication stimulates the “rejuvenation” of cells and subsequent recovery of the mesenchyme-epithelial plasticity of cultured fibroblasts due to the reduced ability to synthesize sufficient to establish the amount of intercellular contacts the extracellular matrix components (fibronectin and collagen), which affects the ability to form spheroids. Culturing spheroids formed with the medication stimulates expression of elastin, collagen type IV, fibronectin extracellular matrix protein that supports the skin elasticity and superficial cells actively express cytokeratin 19. The study results clearly demonstrate the effectiveness of mesotherapeutic treatment for skin rejuvenation.

Occurrence of type VI collagen in extracellular matrix of renal glomeruli and its increase in diabetes

Diabetes ◽  
1990 ◽  
Vol 39 (1) ◽  
pp. 31-37 ◽  
Author(s):  
P. S. Mohan ◽  
W. G. Carter ◽  
R. G. Spiro
Keyword(s):  
Extracellular Matrix ◽  
Type Vi Collagen ◽  
Renal Glomeruli
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