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Results for “Extracellular Matrix”

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At least 505 records · Page 28Linked to original sources

PubMed2003

[Curcumin inhibited the proliferation and extracellular matrix production of human mesangial cells].

OBJECTIVE: Glomerulosclerosis is characterized by extracellular matrix accumulative and is often associated with mesangial cell proliferation. Curcumin showed a protective effect on anti-glomerular basement membrane (anti-GBM) nephritis in vivo, although their cellular localization and mechanism of action is still unclear. In this study, a glomerular mesangial cell line derived from fetus was used to determine whether curcumin could inhibit the cell proliferation and alter the extracellular matrix turnover. METHODS: The cell activity was determined with MTT method. Mesangial cells were cultured in vitro and incubated with 0, 3.125, 6.25, 12.5, 25, 50, 100 and 200 micromol/L curcumin. In addition,human mesangial cells were cultured with or without LPS (10 microg/ml) in presence or absence of various concentrations of curcumin (4, 16 and 200 micromol/L), respectively. The supernatant and cells were collected. Then, the levels of the collagen type IV and III protein in the supernatant were determined by using enzyme-linked immunosorbent assay and the IL-1 beta and MCP-1 mRNA in the cells was measured by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) after subconfluent quiescent mesangial cells were incubated with various concentrations of curcumin for 24 h in vitro. RESULTS: Curcumin at the concentration equal to or over 6.25 micro mol/L was able to inhibit the proliferation of mesangial cells in a dose-dependent manner, the optical density according to the sequential concentrations of curcumin was 0.65 +/- 0.02, 0.62 +/- 0.04, 0.56 +/- 0.01, 0.53 +/- 0.02, 0.51 +/- 0.03, 0.44 +/- 0.05, 0.41 +/- 0.07 and 0.38 +/- 0.06. Without any stimulation, human mesangial cells secreted some collagen type IV and III (10 +/- 9.13 ng/ml and 29.5 +/- 0.58 ng/ml, respectively) and expressed some MCP-1 mRNA, but did not express IL-1 beta mRNA. LPS increased the expression of collagen type IV and III in the culture medium of mesangial cells in vitro [(138.75 +/- 23.23) ng/ml and (38.25 +/- 5.38) ng/ml] and up-regulated the IL-1 beta and MCP-1 mRNA expression [(16.91 +/- 1.68)% and (76.6 +/- 6.59)%]. Yet curcumin could significantly decrease collagen type IV and III in the supernatant of cultured mesangial cells induced by LPS (20.5 +/- 1.00, P < 0.05 and 20.5 +/- 4.12 ng/ml, P < 0.05) and down-regulated the mRNA expression of IL-1 beta and MCP-1 in mesangial cells induced by LPS (P < 0.01). CONCLUSION: Curcumin could inhibit the human mesangial cell proliferation and alter the extracellular matrix turnover, meanwhile it could down-regulate the IL-1 beta and MCP-1 mRNA expression induced by LPS, which may be valuable in decreasing the progression of glomerulosclerosis.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1994

Ultrastructural cytochemical demonstration of proteoglycans and calcium in the extracellular matrix of chondroblastomas.

To clarify the characteristics of the extracellular matrix of chondroblastomas, six cases were studied under the electron microscope, with special reference to proteoglycans and calcium in the cellular areas. In ruthenium hexammine trichloride (RHT)-stained sections the matrix was observed to be composed of rounded or polygonal fine granules and unbanded thin filaments that appeared to link neighboring granules together. Treatment with potassium-pyroantimonate showed intracellular accumulation of precipitates, mainly localized within the cisternae of the rough endoplasmic reticulum as well as in the extracellular matrix. The presence of calcium in the precipitates was confirmed using x-ray energy dispersive analysis. These findings, similar to characteristic features observed in calcifying systems, support the theory that chondroblastomas are of chondrogenic origin.

Calcium↗

PubMed2003

[Matrix metalloproteinases MMP-2 and MMP-9 of wound and burn exudates and their effect on extracellular matrix proteins].

The dynamics of matrix metalloproteinases (MMP), as well as of fibronectin concentration in wound and burn fluids was traced. The wound fluid proteolytic activity was studied by gelatin zymography method. The data on degradation of fibronectin and various laminin isoforms by wound fluid proteases show that laminin-1, laminin-2/4 and fibronectin were degraded by wound fluid into small fragments. Remodelling of extracellular matrix proteins occurs. Dynamics of MMP-2 and MMP-9 content in wound or burn fluids as well as that of adhesive protein fibronectin content could be used as a base for development of method of controlling the extracellular matrix remodelling process.

Burns↗

PubMed2006

Microstructural characteristics of extracellular matrix produced by stromal fibroblasts.

The overall objective of this investigation was to characterize the extracellular matrix deposited by the stromal fibroblasts as a function of time in culture and matrix microstructure. Stromal fibroblasts were seeded onto collagen matrices and cultured for up to 5 weeks. The collagen matrices contained collagen fibrils with an average diameter of 215 +/- 20 nm. When cultured on a collagen film, an average fibril diameter of 62 +/- 39 nm was observed for single layer films with only slight variations with time in culture, and after 1 week of culture between two film layers 67 +/- 47 nm fibrils were observed after 1 week. When the film surface was molded into 1 and 2 microm microgrooves, the initial average fibril diameter of the extracellular matrix was 73 +/- 21 and 73 +/- 31 nm respectively. When cultured on a collagen sponge, an average fibril diameter of 107 +/- 20 nm was initially observed and decreased to 47.5 +/- 17 nm after 1 week in culture. For cells cultured on a collagen sponge, Western blotting showed an increase in myofibroblast phenotype expression with time in culture. Shifts in phenotype were less distinct for cells cultured on collagen films. The microstructure, rather than geometry, of the matrix substrate appeared to influence the newly synthesized extracellular matrix and cell phenotype.

Biomedical Engineering↗

PubMed1996

Transplanted corneal stromal cells in vitreous reproduce extracellular matrix of healing corneal stroma.

PURPOSE: To characterize the extracellular matrix (ECM) formed by corneal stromal cells after injection into the vitreous. This will provide a basis for future studies on the function of corneal ECM macromolecules. METHODS: Cell line from rabbit dermal fibroblasts (RAB9) and primary cultures of rabbit corneal stroma fibroblasts (NRCF) were grown to confluence. For each cell type, approximately 1 x 10(6) cells suspended in basal medium were injected into the vitreous of normal rabbits and observed periodically with a slit lamp. After 1,2, and 4 weeks, eyes were processed for transmission electron microscopy (TEM), immunohistochemistry, immunocytochemistry, and in situ hybridization. RESULTS: All cells showed gradual growth within the vitreous along the needle track. Occurrence of retinal detachment and inflammation was variable. Transmission electron microscopy of NRCF confirmed the deposition of ECM reminiscent of the organization of normal fetal corneal stroma. Similar matrices were produced by RAB9. NRCF deposited collagen fibrils similar in diameter to those seen in normal developing and healing corneal stroma. RAB9 produced collagen fibrils with larger diameters. NRCF-transplanted cells synthesized proteoglycans and collagen immunologically identical to decorin proteins and type VI collagen, indicating that the expression of specific ECM is maintained after transplantation. In addition, in situ hybridization showed that type XII collagen mRNA is synthesized by transplanted NRCF similar to healing corneas. CONCLUSIONS: Corneal stromal cells transplanted into vitreous produce a matrix morphologically and biochemically similar to that in healing corneal stroma.

Animals↗

PubMed1992

Impaired attachment of hepatocytes to extracellular matrix components after chronic ethanol administration.

BACKGROUND: Previous studies have shown that the assembly and properties of the hepatocyte plasma membrane are altered by ethanol administration, indicating possible changes in the receptor-mediated binding of the plasma membrane to extracellular matrix substrates. In the present study, the effects of chronic ethanol consumption on the ability of hepatocytes to attach to various components of the extracellular matrix were investigated. EXPERIMENTAL DESIGN: Rats were pair-fed for 5 weeks with a liquid diet containing either ethanol (as 36% of total calories) or isocaloric carbohydrate. The effects of ethanol treatment on hepatocyte-extracellular matrix interactions was ascertained by determining the ability of isolated hepatocytes to attach to various extracellular matrix substrates. RESULTS: The attachment of hepatocytes, isolated from the ethanol-fed rats, to laminin-coated plates was significantly decreased compared with hepatocytes from chow-fed or pair-fed controls. Greater decreases in attachment were seen when higher numbers of hepatocytes were seeded in the plates. Similar inhibitions of attachment were also observed when fibronectin or type I collagen were used as matrices. Time-course cell attachment assays indicated that the maximum extent of attachment rather than the rate of attachment was primarily altered by chronic ethanol feeding. Hepatocytes from the ethanol-fed rats also detached more readily from the matrix-coated plates than those from the controls. A reduced number of functional surface receptors for matrix components is likely the most important factor that accounts for the ethanol-induced impairment of hepatocyte attachment. CONCLUSIONS: These results indicate that chronic ethanol administration impairs the interactions of hepatocytes with their extracellular matrix and that this defect could lead to alterations of hepatocyte structure and function.

Animals↗

PubMed2001

Three-dimensional supramolecular organization of the extracellular matrix in human and rabbit corneal stroma, as revealed by ultrarapid-freezing and deep-etching methods.

The present work was carried out to clarify the three-dimensional fine structure of extracellular matrix in the cornea, using ultrarapid-freezing and deep-etching methods for electron microscopy. Fresh and glutaraldehyde-fixed samples of human and rabbit posterior corneas were ultrarapidly-frozen onto a copper block cooled by liquid helium or liquid nitrogen, freeze-fractured, deeply etched for 8-10 min and rotary replicated with platinum-carbon. Replicas were examined in a transmission electron microscope equipped with a tilting device. Only structures with repeatedly observed, similar architectural profiles free from ice crystal damage, were taken into account. The very recognizable major collagen fibrils revealed 8-10 nm subfibrils running helically along the fibril long axis. The other extracellular matrix components consisted of: (1) 8-12 nm interfibrillar bridging filaments, frequently ornamented with globular domains, joining neighbouring collagen fibrils like steps of a ladder; (2) 10-20 nm filaments with relatively large globular domains, running on the surface of collagen fibrils along their long axes, and projecting finger-like structures into interfibrillar spaces sometimes attaching to adjacent collagen fibrils; (3) 10-15 nm beaded filaments with a periodicity of 75-110 nm, forming extended networks, especially at the interlamellar interfaces; and (4) 8-14 nm straight or sinuous strands consisting of 4-6 nm repeating subunits or modules, forming extended sheets by lateral association at the Descemet's membrane/stroma interface. In the light of the information available from studies on the localization of extracellular matrix components in the cornea, and by reference to the structural models of extracellular matrix molecules and macromolecular assemblies, we have related the deep-etched extracellular matrix structures described above to: (1) proteoglycans; (2) fibril-associated collagens with interrupted triple helices or FACIT collagens; (3) type VI collagen; and (4) fibronectin, respectively.

Animals↗

PubMed1995

Role of extracellular matrix in attachment, migration, and repair of wounded rabbit cultured gastric cells.

The aim of this study was to determine whether extracellular matrix components affect attachment, proliferation, migration, and repair of wounded rabbit gastric cells in primary culture. Gastric cells were inoculated on culture plates coated without or with collagen type I, type IV, laminin, or fibronectin. The number of attached cells was counted at 3, 5, 24, 48, and 72 h after inoculation. Cell proliferation was assessed with [3H]thymidine incorporation. To assess cell migration and repair after wounding, a confluent monolayer was cut in a standardized manner and the size of the wound area was measured with a computerized analysis system. The number of attached cells increased significantly in plates coated with the extracellular matrix components within 3 h after inoculation. Collagen type I was the most potent stimulator of attachment. Extracellular matrix components did not affect thymidine incorporation. Wound healing was significantly accelerated in the plates coated with collagen type I, type IV, and laminin (70.2 +/- 1.0%, 68.0 +/- 1.0%, and 69.2 +/- 0.9% of initial wound area, respectively, vs. 74.0 +/- 0.6% of initial wound area in controls). Extracellular matrix components play an important role in attachment, migration, and repair of wounded cultured gastric epithelial cells.

Animals↗

PubMed2004

Contact guidance induced organization of extracellular matrix.

The scarring response following injury to the central nervous system disrupts the anatomical organization of nervous tissue posing a barrier to the regeneration of axons. In the present study, using materials with nanometer level surface features we examined whether matrix organization could be controlled by engineering meningeal cell asymmetry. Following 5 days in culture, the organization of meningeal cells along with their cytoskeletal elements and extracellular matrix proteins was evaluated. Meningeal cell morphology was markedly affected by nanometer level substrate topography. Cell alignment increased with increasing surface roughness. In addition, linear arrays of extracellular matrix were expressed that appeared related to cellular orientation. When cultured on substrates with topographical features of less than 10 nm neither cells nor their extracellular matrix showed organizational asymmetry. However, as oriented surface roughness increased, cellular and matrix asymmetrical organization became more pronounced reaching a threshold at 345 nm. These results suggest that biomaterial surface topography or other methods of altering the orientation of cells may be used to engineer orientation into the secreted extracellular matrix and as such may be a potential strategy for developing organized cell-derived matrix as a bridging material for nerve repair or other regenerative applications.

Animals↗

PubMed1990

Syndecan, a developmentally regulated cell surface proteoglycan that binds extracellular matrix and growth factors.

Cellular behaviour during development is dictated, in part, by the insoluble extracellular matrix and the soluble growth factor peptides, the major molecules responsible for integrating cells into morphologically and functionally defined groups. These extracellular molecules influence cellular behaviour by binding at the cell surface to specific receptors that transduce intracellular signals in various ways not yet fully clear. Syndecan, a cell surface proteoglycan found predominantly on epithelia in mature tissues binds both extracellular matrix components (fibronectin, collagens I, III, V, and thrombospondin) and basic fibroblast growth factor (bFGF). Syndecan consists of chondroitin sulfate and heparan sulphate chains linked to a 31 kilodalton (kDa) integral membrane protein. Syndecan represents a family of integral membrane proteoglycans that differ in extracellular domains, but share cytoplasmic domains. Syndecan behaves as a matrix receptor: it binds selectively to components of the extracellular matrix, associates intracellularly with the actin cytoskeleton when cross-linked at the cell surface, its extracellular domain is shed upon cell rounding and it localizes solely to basolateral surfaces of simple epithelia. Mammary epithelial cells made syndecan-deficient become fibroblastic in morphology and cell behaviour, showing that syndecan maintains epithelial cell morphology. Syndecan changes in quantity, location and structure during development: it appears initially on four-cell embryos (prior to its known matrix ligands), becomes restricted in the pre-implementation embryo to the cells that will form the embryo proper, changes its expression due to epithelial-mesenchymal interactions (for example, induced in kidney mesenchyme by the ureteric bud), and with association of cells with extracellular matrix (for example, during B-cell differentiation), and ultimately, in mature tissues becomes restricted to epithelial tissues. The number and size of its glycosaminoglycan chains vary with changes in cell shape and organization yielding tissue type-specific polymorphic forms of syndecan. Its interactions with the major extracellular effector molecules that influence cell behaviour, its role in maintaining cell shape and its spatial and temporal changes in expression during development indicate that syndecan is involved in morphogenesis.

Amino Acid Sequence↗

PubMed2002

Upregulation of extracellular matrix metalloproteinase inducer (EMMPRIN) and gelatinases in human atherosclerosis infected with Chlamydia pneumoniae: the potential role of Chlamydia pneumoniae infection in the progression of atherosclerosis.

Chlamydia pneumoniae infection implicated as an important etiologic factor of atherosclerosis, especially in coronary artery disease (CAD), was found in vitro to be associated with the induction of matrix metalloproteinases (MMPs). An extracellular matrix metalloproteinase inducer (EMMPRIN)/ membrane-type 1 matrix metalloproteinase (MT1-MMP) system which induces and activates MMPs, is suggested to be functional and were upregulated in the failing myocardium. However, the upstream regulation of MMPs by C. pneumoniae within atheroma itself remains unclear. We evaluated the seroepidemiologic study of C. pneumoniae infection in CAD patients (n= 391) and controls (n=97) and performed histopathological and in vitro analysis in atherosclerotic vascular tissues obtained from patients with seropositive to C. pneumoniae (n=20), by using immunochemistry for C. pneumoniae, EMMPRIN/MT1-MMP, MMP-2, and MMP-9. The seropositive rates of both anti-C. pneumoniae IgG and IgA were 56.7% in CAD group and 43.3% in control group (P=0.033). Seropositive rate was increased in subgroups of CAD patients without conventional coronary risk factors compared to those with conventional risk factors. Immunoreactivities of EMMPRIN, MT1-MMP, MMP-2, and MMP-9 were increased in the atheromatous plaque itself, predominantly in immunoreactive macrophages/mononuclear cells to C. pneumoniae. Furthermore, Western blot analysis showed that EMMPRIN and MMP-2 were detected more prominently in atherosclerotic tissues infected with C. pneumoniae compared to control tissues. Zymographic analysis revealed that activities of MMP-2 and MMP-9 were more increased in atherosclerotic tissues infected with C. pneumoniae compared to control tissues. The present study demonstrated upstream regulation of MMPs can be induced by C. pneumoniae within atheromatous plaque itself. These findings help to understand the potential role of C. pneumoniae in the progression of atherosclerosis.

Aged↗

PubMed1994

Latent transforming growth factor-beta 1 associates to fibroblast extracellular matrix via latent TGF-beta binding protein.

The role of latent transforming growth factor-beta (TGF-beta) binding protein (LTBP) in the association of TGF-beta 1 to the extracellular matrix of cultured fibroblasts and HT-1080 fibrosarcoma cells was studied by immunochemical methods. The matrices were isolated from the cells, and the levels of LTBP and TGF-beta 1 were estimated by immunoblotting and immunoprecipitation. LTBP, TGF-beta 1, and its propeptide (latency-associated peptide, LAP) were found to associate to the extracellular matrix. Immunoblotting analysis indicated that treatment of the cells with plasmin resulted in a concomitant time and dose dependent release of both LTBP and TGF-beta 1 from the extracellular matrix to the supernatant. Comparison of molecular weights suggested that plasmin treatment resulted in the cleavage of LTBP from the high molecular weight fibroblast form to a form resembling the low molecular weight LTBP found in platelets. Pulse-chase and immunoprecipitation analysis indicated that both the free form of LTBP and LTBP complexed to latent TGF-beta were efficiently incorporated in the extracellular matrix, from where both complexes were slowly released to the culture medium. Addition of plasmin to the chase solution resulted, however, in a rapid release of LTBP from the matrix. Fibroblast derived LTBP was found to associate to the matrix of HT-1080 cells in a plasmin sensitive manner as shown by immunoprecipitation analysis. These results suggest that the latent form of TGF-beta 1 associates with the extracellular matrix via LTBP, and that the release of latent TGF-beta 1 from the matrix is a consequence of proteolytic cleavage(s) of LTBP.

Carrier Proteins↗

PubMed1983

Extracellular matrix during laminar pattern formation of neocortex in normal and reeler mutant mice.

The spatial and temporal distribution of extracellular matrix, which occupied the large extracellular spaces in the developing cerebral cortex, was studied during pre- and perinatal ontogenesis of normal and reeler mutant mice. Colloidal iron-staining material was localized principally in the marginal zone and subplate of normal mice, whereas in reeler mutants, most of the material was found in the outer layers of the cortex. Patterns of extracellular matrix localization in both genotypes followed the laminar pattern formation of cerebral cortex architecture. Histochemical ultrastructural visualization of this extracellular matrix and its susceptibility to enzymatic treatment suggested that the major components are glycosaminoglycans. Their possible role in relation to afferent axon targeting is discussed.

Animals↗

PubMed2003

Fragmentation of extracellular matrix by hypochlorous acid.

The interaction of extracellular matrix with cells regulates their adhesion, migration and proliferation, and it is believed that damage to vascular matrix components is a factor in the development of atherosclerosis. Evidence has been provided for a role for the haem enzyme MPO (myeloperoxidase), released by activated monocytes (and possibly macrophages), in oxidative events within the artery wall. As MPO is released extracellularly, and is highly basic, it might be expected to associate with poly-anionic matrix components thereby localizing damage to these materials. In this study the reaction of the MPO-derived oxidant hypochlorous acid (HOCl) with extracellular matrix from vascular smooth muscle cells and healthy pig arteries has been examined. HOCl is rapidly consumed by such matrix samples, with the formation of matrix-derived chloramines or chloramides. The yield of these intermediates increases with HOCl dose. These materials undergo a time- and temperature-dependent decay, which parallels the release of sugar and protein components from the treated matrix, consistent with these species being important intermediates. Matrix damage is enhanced by species that increase chloramine/chloramide decomposition, with copper and iron ions being effective catalysts, and decreased by compounds which scavenge chloramines/chloramides, or species derived from them. The effect of such matrix modifications on cellular behaviour is poorly understood, though it is known that changes in matrix materials can have profound effects on cell adhesion, proliferation, growth and phenotype. The observed matrix modifications reported here may therefore modulate cellular behaviour in diseases such as atherosclerosis where MPO-derived oxidants are generated.

Amides↗

PubMed1993

Mediation of endothelial injury following neutrophil adherence to extracellular matrix.

Since polymorphonuclear leukocytes (PMN) rapidly migrate across the endothelial barrier and attach to extracellular matrix components, we tested the hypothesis that adhesion of PMN to matrix proteins can mediate endothelial injury following PMN activation. Studies were made using gelatin- and fibronectin-coated polycarbonate microporous filters (10 microns thick) on which confluent monolayers of bovine pulmonary microvessel endothelial cells were grown. PMN were layered either directly onto endothelial cells (at a ratio of 10:1) ("upright system") or onto gelatin- and fibronectin-coated filters with the endothelial monolayer grown on the underside of the filter without contact between PMN and endothelial cells ("inverted system"). PMN were activated with phorbol 12-myristate 13-acetate (PMA; 5 x 10(-9) M) in both systems. PMN activation increased endothelial permeability to 125I-labeled albumin in upright as well as inverted systems. Pretreatment of PMN with anti-CD18 monoclonal antibodies IB4 or R15.7, which inhibited PMN adherence to matrix constituents as well as to endothelial cells, prevented the permeability increase in both configurations. This effect of anti-CD18 monoclonal antibodies (mAbs) was not ascribed to a reduction in PMN activation, since PMA-induced superoxide generation was unaffected. We conclude that activation of PMN adherent to extracellular matrix proteins increases endothelial permeability to albumin and that this response is dependent on PMN adhesion to the matrix. The results support the concept that PMN-mediated increase in endothelial permeability is the result of "targeted" release of PMN products independent of whether the PMN are adherent to the extracellular matrix or the endothelium.

Animals↗

PubMed1993

Alterations of T-cell: extracellular matrix proteins interactions in psoriasis.

Recent data indicate that extracellular matrix proteins (collagens, fibronectin) co-stimulate T-cell lymphoproliferative responses in vitro. We have studied the co-stimulatory activities of those proteins in patients with psoriasis, a disease in which T cells infiltrating the skin are continuously exposed to collagen and fibronectin. CD3-triggered T-cell proliferative responses were lower in psoriasis but could be enhanced by collagens I and IV and fibronectin. Interestingly, collagen-I-dependent co-stimulation was markedly decreased in patients with psoriasis, while there was a trend towards the enhancement of collagen-IV-induced responses. Those disturbances were most frequently seen in patients with active and widespread lesions. It appears that abnormalities of extracellular matrix protein-derived signals could play a role in the immunopathology of psoriasis.

Adult↗

PubMed2006

Extracellular matrix deposition by fibroblasts is necessary to promote capillary-like tube formation in vitro.

The contribution of the cellular and fibrillar microenvironment to angiogenesis still remains unclear. Our purpose was to evaluate the effect of the extracellular matrix deposited by fibroblasts on the capacity of human endothelial cells to form capillaries in vitro. We have drastically decreased the amount of extracellular matrix surrounding fibroblasts in our model of endothelialized-reconstructed connective tissue (ERCT) by culturing it without ascorbate. Under these conditions, the number of capillary-like tubes (CLT) formed by endothelial cells was reduced by up to 10-fold after 31 days of culture compared to controls. This decrease was due neither to a variation of MMP-2 and MMP-9 secretion, nor to a reduction in the number of fibroblasts and/or endothelial cells, or a diminution of fibroblast growth factor 2 (FGF2) synthesis. The secretion of vascular endothelial growth factor (VEGF) by fibroblasts accounted for 25-70% of the capillary-like tube formation when tissues were cultured in the presence or absence of ascorbate, as demonstrated by VEGF-blocking studies. The culture of endothelial cells on a similar extracellular matrix but in the absence of living fibroblasts did not promote the formation of CLT, even when tissues were fed with fibroblast-conditioned medium. Thus, the deposition of a rich extracellular matrix by living fibroblasts appeared necessary, but not sufficient to promote capillary-like formation. Fibroblasts seem to induce endothelial cells to spontaneously form CLT by secreting and organizing an abundant extracellular matrix, which creates a microenvironment around cells that could in turn trap growth factors produced by fibroblasts and promote three-dimensional cell organization.

Ascorbic Acid↗

PubMed2002

Versican: a versatile extracellular matrix proteoglycan in cell biology.

Versican is a large extracellular matrix proteoglycan that is present in a variety of tissues. Successful cloning of the gene in man, mouse, cow and chicken has revealed the existence of at least four splice variants of versican, which differ in the size of the core protein and the number of glycosaminoglycan chains. The highly interactive nature of versican provides a basis for its importance as a structural molecule, creating loose and hydrated matrices during key events in development and disease; and by interacting either directly with cells or indirectly with molecules that associate with cells to, in part, regulate cell adhesion and survival, cell proliferation, cell migration and extracellular matrix assembly. Several studies within the past two years have confirmed a significant role for versican in regulating cell phenotype.

Animals↗