scholarly journals Expression of extracellular matrix components is regulated by substratum.

1990 ◽  
Vol 110 (4) ◽  
pp. 1405-1415 ◽  
Author(s):  
C H Streuli ◽  
M J Bissell
Keyword(s):  
Extracellular Matrix ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Type I Collagen ◽  
Basement Membranes ◽  
Type I ◽  
Collagen Gels ◽  
Extracellular Matrix Components ◽  
Matrix Components ◽  
Cells Cultured

Reconstituted basement membranes and extracellular matrices have been demonstrated to affect, positively and dramatically, the production of milk proteins in cultured mammary epithelial cells. Here we show that both the expression and the deposition of extracellular matrix components themselves are regulated by substratum. The steady-state levels of the laminin, type IV collagen, and fibronectin mRNAs in mammary epithelial cells cultured on plastic dishes and on type I collagen gels have been examined, as has the ability of these cells to synthesize, secrete, and deposit laminin and other, extracellular matrix proteins. We demonstrate de novo synthesis of a basement membrane by cells cultured on type I collagen gels which have been floated into the medium. Expression of the mRNA and proteins of basement membranes, however, are quite low in these cultures. In contrast, the levels of laminin, type IV collagen, and fibronectin mRNAs are highest in cells cultured on plastic surfaces, where no basement membrane is deposited. It is suggested that the interaction between epithelial cells and both basement membrane and stromally derived matrices exerts a negative influence on the expression of mRNA for extracellular matrix components. In addition, we show that the capacity for lactational differentiation correlates with conditions that favor the deposition of a continuous basement membrane, and argue that the interaction between specialized epithelial cells and stroma enables them to create their own microenvironment for accurate signal transduction and phenotypic function.

scholarly journals Extracellular matrix components of the mouse thymus microenvironment: ontogenetic studies and modulation by glucocorticoid hormones.

1991 ◽  
Vol 39 (11) ◽  
pp. 1539-1546 ◽  
Author(s):  
J Lannes-Vieira ◽  
M Dardenne ◽  
W Savino
Keyword(s):  
Extracellular Matrix ◽  
Basement Membrane ◽  
Type I Collagen ◽  
Basement Membranes ◽  
Thymic Epithelial Cell ◽  
Epithelial Cell Line ◽  
Type I ◽  
Extracellular Matrix Components

The present investigation was an ontogenetic study on the distribution of extracellular matrix (ECM) components in the thymic microenvironment of C57BL/6 mice (comprising young and old adults and developing embryos) and NZB mice. In addition, we evaluated the in vivo and in vitro influence of hydrocortisone treatment on basement membrane protein production by a thymic epithelial cell line. In young normal animals, Type I collagen was restricted to the interstitial spaces of the capsule and septa, where Type IV collagen, fibronectin, and laminin could be detected in the basement membranes. In addition, fibronectin-containing fibers were seen within the medulla of the thymic lobules. The ECM distribution pattern in the developing embryos was distinct from that observed in adults, since a fine meshwork of basement membrane-containing proteins was clearly seen throughout the parenchyma. Moreover, aging normal and NZB mice exhibited a denser ECM pattern than young adult normal animals. Treatment with hydrocortisone, both in vivo and in vitro, resulted in enhancement of ECM expression, detected in mice as early as 2 hr post injection and lasting for several days. Considering that the fluctuations of ECM expression parallel important events in thymocyte differentiation, we discuss the possibility that the two phenomena may be associated.

scholarly journals Extracellular matrix of lymphoid tissues in the chick.

1989 ◽  
Vol 37 (5) ◽  
pp. 757-763 ◽  
Author(s):  
A Colombatti ◽  
A Poletti ◽  
A Carbone ◽  
D Volpin ◽  
G M Bressan
Keyword(s):  
Extracellular Matrix ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Basement Membranes ◽  
Intestinal Lumen ◽  
Lymphoid Tissues ◽  
White Pulp ◽  
Extracellular Matrix Components ◽  
Coarse Fibers ◽  
Distribution Of Components

We describe the immunohistochemical distribution of components of the extracellular matrix of the chick lymphoid system. In the thymus, basement membranes of epithelial cells bordering the lobules were intensely stained by laminin antibodies; fibronectin antibodies labeled the capsule and the septal matrix, and similar reactivity was seen with tropoelastin and gp 115 antibodies. No positivity was detected with any of the antibodies within the cortical parenchymal cells. Laminin was not detected in the medullary parenchyma, whereas fibronectin was present as coarse fibers. Tropoelastin and gp 115 appeared as a finer and more diffuse meshwork. In the bursa, laminin antibodies outlined the epithelial cells separating the cortex from the medulla. Fibronectin, tropoelastin, and gp 115 antibody stained the interfollicular septa and the cortical matrix, although to a different extent. Laminin was also detected in association with the interfollicular epithelium (IFE) basement membrane, whereas no staining was found underneath the follicle-associated epithelium (FAE). FAE cells not only lack a proper basement membrane but are also not separated from medullary lymphocytes by any of the other extracellular matrix components were investigated. Consequently, medullary lymphocytes are not sequestered, and can come easily into contact with antigens present in the intestinal lumen. All four antibodies stained the spleen capsule and spleen blood vessels, tropoelastin and gp 115 antibodies giving the strongest reactivity. A fine trabecular staining pattern was detected with gp 115 antibodies in the white pulp.

scholarly journals Extracellular matrix of the human thymus: immunofluorescence studies on frozen sections and cultured epithelial cells.

1985 ◽  
Vol 33 (7) ◽  
pp. 655-664 ◽  
Author(s):  
S Berrih ◽  
W Savino ◽  
S Cohen
Keyword(s):  
Extracellular Matrix ◽  
Epithelial Cells ◽  
Type Iv Collagen ◽  
Type I Collagen ◽  
Basement Membranes ◽  
Thymic Epithelial Cells ◽  
Perivascular Spaces ◽  
Type I ◽  
Type Iv

The immunohistochemical detection of elements of the human thymic extracellular matrix in situ and in vitro is described. In the normal thymus, the intracapsular and intraseptal fibers were strongly labeled by anti-type I collagen antiserum. Basement membranes bordering the capsule, septae, and perivascular spaces were intensely stained by anti-type IV collagen, anti-fibronectin, and anti-laminin sera. In hyperplastic myasthenia gravis thymuses, the major changes consisted of discontinuities of the basement membrane adjacent to clusters of epithelial (keratin-containing) cells, among which an unusual connective framework (densely labeled by all the antisera) was observed. In vitro, most epithelial cells were strongly labeled by antifibronectin serum and to a lesser extent by the anti-type IV collagen and anti-laminin sera. In addition, fibronectin, laminin, and type IV collagen were detected in the intercellular spaces bordering the epithelial cells in culture. Results show that thymic epithelial cells participate in the synthesis of extracellular matrix elements, which as a result of their localization and influence on epithelial cell growth, should be regarded as constitutive components of the thymic microenvironment.

Repair of critical size rat calvarial defects using extracellular matrix protein gels

1995 ◽  
Vol 83 (4) ◽  
pp. 710-715 ◽  
Author(s):  
Thomas M. Sweeney ◽  
Lynne A. Opperman ◽  
John A. Persing ◽  
Roy C. Ogle
Keyword(s):  
Extracellular Matrix ◽  
Basement Membrane ◽  
Bone Repair ◽  
Type I Collagen ◽  
Critical Size ◽  
Type I ◽  
Collagen Gels ◽  
Content Type ◽  
Calvarial Defects ◽  
Fine Print

✓ In this study the authors examined the capacity of gels of reconstituted basement membrane, laminin, and type I collagen to mediate repair of critical size defects in rat calvaria. Although autografts are widely used to repair bone defects caused by trauma or surgical treatment of congenital malformations, neoplasms, and infections, an adequate quantity of graft is not always available. Allogenic bone is readily available, but its use is associated with an increased incidence of nonunion, fatigue fracture, and rejection. Biologically active, purified components of basement membranes, which have been shown to promote osteogenic differentiation and angiogenesis in vitro and type I collagen (the major constituent of bone extracellular matrix) can be formed into native isotonic space-filling gels. In this study critical size calvarial defects were created in retired male Sprague-Dawley rats. Thirty-six animals were divided into seven groups. Group 1 (control) received no treatment for the defects. Group 2 animals were implanted with methylcellulose. Groups 3, 4, 5, and 6 were implanted with gels of type I collagen, reconstituted basement membrane, or laminin, respectively. The last group of three animals (Group 7) was implanted with 100 µg of type I collagen gels (identical to Group 3) and sacrificed at 20 weeks following a single CT scan to determine if complete healing could be obtained with this method given sufficient time. Except for rats in the type I collagen group that was evaluated by multiple computerized tomography (CT) scans biweekly from 2 to 12 weeks, bone repair was evaluated using CT at 12 weeks. Healing was quantified using three-dimensional reconstruction of CT. Following the final CT scan in each experimental group, animals were sacrificed, and a sample of tissues was evaluated by conventional histology. Animals treated with type I collagen gels showed 87.5% repair of the area of the defects at 12 weeks and 92.5% repair by 20 weeks. Increasing the gel volume 1.5 × accelerated complete repair to 3 months. Murine-reconstituted basement membrane and laminin gels induced 55.5% and 46.3% repair, respectively, at 3 months. In untreated control animals 7% repair of the area of the defects showed at 3 months. Histological analysis confirmed new bone formation in partial and completely healed defects. Bioengineered native collagen gels may have wide applicability for bone repair as an alternative bone graft material alone, in combination with autograft or marrow aspirate, or as a delivery system for osteogenic growth factors.

scholarly journals Thrombospondin gene expression by endothelial cells in culture is modulated by cell proliferation, cell shape and the substratum

1990 ◽  
Vol 268 (1) ◽  
pp. 225-230 ◽  
Author(s):  
A E Canfield ◽  
R P Boot-Handford ◽  
A M Schor
Keyword(s):  
Gene Expression ◽  
Cell Proliferation ◽  
Endothelial Cells ◽  
Cell Shape ◽  
Type I Collagen ◽  
Three Dimensional ◽  
Type I ◽  
Mrna Levels ◽  
Collagen Gels ◽  
Cells Cultured

Endothelial cells plated on the surface of a two-dimensional substratum (gelatin-coated dishes, dishes coated with native type I collagen or collagen gels) form a cobblestone monolayer at confluence, whereas cells plated within a three-dimensional gel matrix elongate into a sprouting morphology and self-associate into tube-like structures. In this study, we have compared the synthesis of thrombospondin by quiescent endothelial cells displaying (a) the same morphological phenotype (cobblestone) on different substrata (gelatin and collagen) and (b) different morphological phenotypes (cobblestone and sprouting) on the same substratum (collagen). We demonstrate that thrombospondin is a major biosynthetic product of confluent, quiescent cells cultured on dishes coated with either gelatin or collagen, and that the synthesis of this protein is markedly decreased when cells are plated on or in three-dimensional collagen gels. Moreover, we demonstrate that cells plated in gel (sprouting) secrete less thrombospondin than do cells plated on the gel surface (cobblestone). The regulation of thrombospondin synthesis is reversible and occurs at the level of transcription, as steady-state mRNA levels for thrombospondin decrease in a manner comparable with the levels of protein secreted by these cells. We also show that mRNA levels for laminin B2 chains are increased when cells are cultured on and in collagen gels compared with on gelatin-coated dishes, suggesting that the syntheses of thrombospondin and laminin are regulated by different mechanisms. When cells are cultured on gelatin- or collagen-coated dishes, thrombospondin gene expression is directly proportional to the proliferative state of the cultures. By contrast, the synthesis of thrombospondin by cells cultured on collagen gels remains at equally low levels whether they are labelled when they are sparse and rapidly proliferating or when they are confluent and quiescent. Fibronectin synthesis was found to increase with increasing confluency of the cells plated on all three substrata. These results demonstrate that thrombospondin gene expression is modulated by cell shape, cell proliferation and the nature of the substratum used for cell culture.

scholarly journals TEF-1 and C/EBPβ are major p38α MAPK-regulated transcription factors in proliferating cardiomyocytes

2006 ◽  
Vol 396 (1) ◽  
pp. 163-172 ◽  
Author(s):  
Concetta Ambrosino ◽  
Tomoko Iwata ◽  
Claudio Scafoglio ◽  
Massimo Mallardo ◽  
Rüdiger Klein ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Transcription Factors ◽  
Environmental Stress ◽  
Type I Collagen ◽  
Specific Gene ◽  
Type I ◽  
Transcriptional Enhancer ◽  
Extracellular Matrix Components ◽  
Mitogen Activated Protein ◽  
P38 Mapks

p38 MAPKs (mitogen-activated protein kinases) play important roles in the regulation of cellular responses to environmental stress. Recently, this signalling pathway has also been implicated in the regulation of processes unrelated to stress, for example, in T lymphocytes and cardiomyocytes. In order to identify molecular targets responsible for the housekeeping functions of p38 MAPKs, we have analysed the differences in the transcriptomes of normally proliferating wild-type and p38α knockout immortalized embryonic cardiomyocytes. Interestingly, many potential components of the myocardium extracellular matrix were found to be upregulated in the absence of p38α. Further analysis of the microarray data identified TEF-1 (transcriptional enhancer factor-1), a known regulator of heart-specific gene expression, and C/EBPβ (CCAAT/enhancer-binding protein β), as the two transcription factors the binding sites of which were most enriched in the promoters of p38α-regulated genes. We have focused on the study of the extracellular matrix component COL1A1 (α1 chain of type I collagen) and found evidence for the involvement of both TEF-1 and C/EBPβ in the p38α-dependent inhibition of COL1A1 transcription. Our data therefore show that p38 MAPKs regulate TEF-1 and C/EBPβ transcriptional activity in the absence of environmental stress and suggests a role for p38α in the expression of extracellular matrix components that maintain organ architecture.

scholarly journals Arg-Gly-Asp-containing peptides expose novel collagen receptors on fibroblasts: implications for wound healing.

1991 ◽  
Vol 2 (12) ◽  
pp. 1035-1044 ◽  
Author(s):  
M V Agrez ◽  
R C Bates ◽  
A W Boyd ◽  
G F Burns
Keyword(s):  
Extracellular Matrix ◽  
Wound Healing ◽  
Type I Collagen ◽  
Regulatory Control ◽  
Type I ◽  
Collagen Gels ◽  
Collagen Matrices ◽  
Surface Receptors ◽  
Rgd Sequence ◽  
Collagen Receptors

Integrins are a family of cell-surface receptors intimately involved in the interactions of cells with their extracellular matrix. These receptors comprise an alpha and beta subunit in noncovalent association and many have been shown to recognize and bind an arginine-glycine-aspartate (RGD) sequence contained within their specific extracellular matrix ligand. Fibroblasts express integrin receptors belonging to two major subfamilies. Some of the members within the subfamily defined by beta 1 (VLA) are receptors for collagen but, perhaps surprisingly, the other major subfamily of integrins on fibroblasts--that defined by the alpha chain of the vitronectin receptor, alpha v--all appear to bind primarily vitronectin and/or fibronectin. In the present study we show that RGD-containing peptides expose cryptic binding sites on the alpha v-associated integrins enabling them to function as collagen receptors. The addition of RGD-containing peptides to fibroblasts cultured on type I collagen induced dramatic cell elongation and, when the cells were contained within collagen matrices, the peptides induced marked contraction of the gels. These processes were inhibited by Fab fragments of a monoclonal antibody against an alpha v integrin. Also, alpha v-associated integrins from cell lysates bound to collagen I affinity columns in the presence, but not in the absence, of RGD-containing peptides. These data suggest a novel regulatory control for integrin function. In addition, because the cryptic collagen receptors were shown to be implicated in the contraction of collagen gels, the generation of such binding forces suggests that this may be the major biological role for these integrins in processes such as wound healing.

Extracellular matrix components synthesized by human amniotic epithelial cells in culture

Cell ◽  
1980 ◽  
Vol 19 (4) ◽  
pp. 1053-1062 ◽  
Author(s):  
Kari Alitalo ◽  
Markku Kurkinen ◽  
Antti Vaheri ◽  
Thomas Krieg ◽  
Rupert Timpl
Keyword(s):  
Extracellular Matrix ◽  
Epithelial Cells ◽  
Cells In Culture ◽  
Amniotic Epithelial Cells ◽  
Extracellular Matrix Components ◽  
Human Amniotic Epithelial Cells ◽  
Matrix Components
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