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Results for “Extracellular Matrix”

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At least 613 records · Page 34Linked to original sources

PubMed2002

Deficiency of a 180-kDa extracellular matrix protein in Fukuyama type congenital muscular dystrophy skeletal muscle.

Abnormalities of the proteins constituting the extracellular matrix have been shown to play important roles in the molecular pathogenesis of muscular dystrophies. In the present study, we have established a monoclonal antibody against a human skeletal muscle extracellular matrix protein. The antibody M1 recognized a single 180-kDa protein (p180) by immunoblot analysis of normal human skeletal muscle and gave a strong and continuous signal along the sarcolemma by immunohistochemical analysis. Furthermore, p180 could be solubilized either under a strong alkaline condition, or in the presence of EDTA or detergents such as Triton X-100, indicating that p180 was an extracellular matrix protein. Interestingly, p180 was deficient in the skeletal muscle of the patients with Fukuyama-type congenital muscular dystrophy (FCMD), but not other muscular diseases, by both immunohistochemical and immunoblot analyses. We presume that the deficiency of p180 in FCMD is caused specifically by the primary deficiency of fukutin, the causative protein of FCMD, and plays an important role in muscle cell degeneration in this disease.

Animals↗

PubMed1993

[Immunohistopathological properties of cytoskeletal proteins and extracellular matrix components in pleomorphic adenomas of salivary glands].

Twenty-five pleomorphic adenomas and 10 normal salivary glands were immunohistochemically studied with respect to cytoskeletal proteins and extracellular matrix components to observe the relationship between these components and the differentiation of tumor cells in pleomorphic adenomas. For immunohistochemical observation, keratin (AE1), vimentin (V9), alpha-smooth muscle actin (1A4) and type IV collagen (JK-199) were studied by means of monoclonal antibodies, and laminin (LM) and fibronectin (FN) were analysed with polyclonal antibodies. AE1 was localized in inner tubular cells, and 1A4 was identified in spindle and leiomyomatous cells. These observations may provide evidence of differentiation into ductal epithelia and myoepithelial cells, respectively. Positive staining for V9 in cuboidal cells suggests dedifferentiation. The extracellular matrix components, JK-199, LM and FN, were localized in surrounding areas of cells stained by V9 and/or 1A4. This suggests that expression of these cytoskeletal proteins and extracellular matrix components may affect each other, and ther by contribute to cellular differentiation and production of extracellular matrix.

Adenoma, Pleomorphic↗

PubMed1989

Cultured bovine bone cells synthesize basic fibroblast growth factor and store it in their extracellular matrix.

Bone contains various growth factors, including fibroblast growth factor (FGF). The cellular origins of the growth factors found in bone are not known. We examined whether cultured fetal bovine bone cells synthesize FGF. These cells express characteristic markers of the osteoblast phenotype, including expression of bone Gla protein (osteocalcin) and mineralization. Heparin-Sepharose fractionation of cell extracts revealed that bone cells contained a basic FGF (bFGF)-like molecule, that displayed high affinity for heparin. The growth factor was mitogenic for adrenal cortex-derived endothelial cells and osteoblast-like bone cells. The major peak of biological activity corresponded to a peak of immunoreactive bFGF. When analyzed by Western blot, the active fractions contained a bFGF-like immunoreactive species with a mol wt of 15,000, a mass identical to that of (des-1-15)bFGF. Based on RIA, the bone cell extract contained an estimated 95 ng bFGF/mg cell protein. An acidic FGF-like molecule with lower affinity for heparin was also present in the purified bone cell extracts, although at an approximately 10-fold lower concentration than bFGF. These results demonstrate that bone cells synthesize a mitogen indistinguishable from bFGF. In addition, Northern analysis revealed that the bone cells expressed 3.5- and 7.0-kilobase bFGF gene transcripts. We next examined whether the bone cell-derived bFGF is stored in a bioactive form in the extracellular matrix. Bone cells synthesized an extracellular matrix which was mitogenic for adrenal cortex-derived endothelial cells. However, if the bone cell extracellular matrix was preincubated with neutralizing anti-bFGF antibodies, its mitogenic properties were abolished. This suggests that bone cell-derived bFGF may function as an autocrine or paracrine mitogen via its deposition into the extracellular matrix of bone.

Adrenal Cortex↗

PubMedDate not supplied

[Effects of PDGF AB on extracellular matrix synthesis by human mammary fibroblasts].

PDGF AB effect on extracellular matrix protein synthesis and release by a primary culture of non transformed human mammary fibroblasts was analyzed. Primarily PDGF AB induced a modified protein distribution, with a global enhancement of secreted proteins as compared to intracytoplasmatic proteins. Furthermore, an increase in synthesis and release of the extracellular matrix proteins such as fibronectin and type I and IV collagens upon PDGF AB treatment with specific immunoprecipitation was demonstrated.

Aged↗

PubMed1997

Improved preservation of the subepidermal extracellular matrix in axolotl embryos using electron microscopical techniques based on cryoimmobilization.

The purpose of this metholdological survey was to find optimal methods for the fixation and demonstration of glycosaminoglycans, mainly hyaluronan, and proteoglycans, in subepidermal extracellular matrix (ECM) regions of axolotl embryos. We compared living ECM in the laser-scanning microscope (LSM) with chemically fixed or cryoimmobilized extracellular matrix in the transmission (TEM) and scanning electron microscope (SEM). The gel-like structure of living extracellular matrix in the LSM undoubtedly provides the most natural state, whereas shrinkage of the extracellular matrix occurs during conventional fixation and dehydration for TEM or SEM. Among the methods used for fixation and processing of subepidermal extracellular matrices for SEM, plunge-freezing/freeze-drying is to be preferred. Still more satisfying, however, are results obtained with high-pressure frozen/freeze-substituted ECM material in the TEM, for which 10% polyvinyl pyrrolidon +7% methanol was used as a cryoprotectant before high-pressure freezing. In these specimens, no freeze-damage could be observed and they could be regarded as adequately frozen. Conversely, the yield in adequately frozen specimens without cryoprotection was insufficient. In these specimens, the ECM contained honeycomb-like structures which, in the current literature, are regarded as hyaluronan.

Ambystoma↗

PubMedDate not supplied

Antisense basic fibroblast growth factor oligonucleotide reduced adhesion of retinal pigment epithelial cells to extracellular matrix molecules and their proliferation.

We investigated the effect of extracellular matrix molecules on the adhesion of retinal pigment epithelial cells and their subsequent proliferation. Fibronectin, collagen type I and vitronectin enhanced their adhesion and proliferation. In addition, the effect of basic fibroblast growth factor (bFGF) on their adhesion and proliferation was studied. bFGF enhanced their adhesion and proliferation, whereas antisense bFGF reduced their adhesion to and their proliferation on extracellular matrix molecules.

Animals↗

PubMedDate not supplied

Antiproliferative and antimigratory effects of doxorubicin in human osteosarcoma cells exposed to extracellular matrix.

Osteosarcoma cells are involved in the remodeling of the extracellular matrix (ECM) that affects their growth, invasive and metastatic activities. The tumour ECM provided effective protection against chemotherapy agents in several previously studied malignancies. The current study examined the effects of doxorubicin on cells that were migrated into a 3-dimensional extracellular matrix gel (ECM-gel) in comparison with its effects on cells remaining in the monolayer compartment. A human osteosarcoma cell line (OSCORT) was treated with doxorubicin in monolayer culture for 4 or 24 hours, and then overlaid by ECM-gel for 24 hours. Tumour cells remaining in the monolayer were separated from the cells migrated into ECM-gel, and both of them were characterized. OSCORT cells migrated into ECM-gel showed elevated levels and activity of topoisomerase II, increased protein expression of beta1 integrin and matrix metalloproteinase-9 activity. Doxorubicin treatment for 4 hours resulted in increased cytotoxicity in the monolayer compartment relative to the cells migrated into ECM-gel, whereas 24-hour treatment at a low concentration (0.01 microg/ml) showed an antimigratory effect. Different antiproliferative and antimigratory effects of doxorubicin treatment schedules warrant short-term, high-dose treatment for targeting the tumour growth, and long-term, low-dose treatment for targeting the invasion of osteosarcoma.

Antibiotics, Antineoplastic↗

PubMed1997

Extracellular matrix of peripheral nerves in diabetes.

Peripheral nerves are susceptible to develop multiple changes in their morphology and biochemical composition as consequences of diabetes mellitus. This review focuses on diabetes-induced alterations of the extracellular matrix of the peripheral nerves, and on the potential molecular mechanisms causing these changes. The interest towards the extracellular matrix of peripheral nerves of diabetic patients is highlighted by the fact that the extracellular matrix does not only mechanically support the cells which it surrounds, but it also regulates their behavior through specific interactions mediated via molecules on the cell surface, such as integrin receptors and cell surface proteoglycans. Thus, changes in the structure and composition of the extracellular matrix may alter cellular functions in multiple ways. At the ultrastructural level, these changes include e.g. thickening of vascular, perineurial and Schwann cell associated basement membranes; accumulation of microfibrillar material in the vicinity of perineurial cells; and increased diameter of endoneurial collagen fibrils. At the molecular level, the changes may be associated with altered metabolism of various collagen types, such as type I, III, IV and VI collagens.

Animals↗

PubMed1998

Stimulation of extracellular matrix components in the normal brain by invading glioma cells.

Malignant gliomas are characterized by an extensive invasion of tumor cells into the normal brain parenchyma. A substantial amount of data indicates that cell movement in general is regulated by specific interactions between extracellular matrix components and specific cell-surface receptors. In the present work, multicellular spheroids from 4 human glioma cell lines (U-373Mg, A-172Mg, U-251Mg and HF-66) were confronted with normal rat brain cell aggregates in vitro, which resulted in a progressive invasion of tumor cells into the brain aggregates. The co-cultures were then sectioned and immuno-stained for specific extracellular matrix components (laminin, fibronectin and collagen type IV) and for specific cell-surface receptors which bind to these components (integrins beta1, beta4, alpha3, alpha6). In addition, flow-cytometric measurements and Northern blot analyses showed expression of several different integrins within the cell lines. The alpha3 subunit was expressed strongly in all cell lines. Whereas the beta1 subunit was expressed weakly in exponentially growing monolayer cultures, it showed a pronounced expression in multicellular spheroids, indicating that the integrin expression may vary depending on the micro-environment within a tumor. Furthermore, normal brain tissue was able to produce laminin when confronted with the glioma cells, which also was observed for fibronectin and collagen type IV. The relevance of our observations to the in vivo situation was investigated further by immuno-staining 5 human glioma biopsy samples for laminin. In some areas of the tumors, specific deposits of laminin were observed. In conclusion, we have shown that normal brain tissue has the ability to produce extracellular matrix components, such as laminin, collagen type IV and fibronectin, when confronted with invading glioma cells. Our results show that the glioma cells express specific integrins which can interact with these extracellular matrix components. Such interactions may facilitate tumor cell migration and invasion.

Animals↗

PubMed1991

Survival and B-cell function of neonatal pig pancreatic islet-like cell clusters in an extracellular matrix.

Islet-like cell clusters (ICCs), formed from single cells of pig pancreas in suspension culture, were embedded in an extracellular matrix. It was recently reported that nicotinamide prevented dissolution of the extracellular matrix by the ICCs. In this experiment, various conditions for embedded culture of ICCs in an extracellular matrix were studied, in an attempt to maintain the function as well as the extracted insulin content of culture specimens. The ICCs in the matrix were refed with RPMI 1640, containing 10 mM nicotinamide, 10% fetal bovine serum (FBS), 11 mM D-glucose and with or without 0.1 mM 3-isobutyl-1-methylxanthine (IBMX) or 1.0 micrograms/ml caerulein. A comparison between the different culture media showed that embedded ICCs, maintained in RPMI 1640 with caerulein, in the presence of nicotinamide, had higher insulin content accumulation than when maintained in medium containing nicotinamide alone, but had impaired glucose-stimulated insulin secretion. In the medium containing IBMX and nicotinamide, embedded ICCs showed higher insulin accumulation but lower insulin content, compared to ICCs maintained in the presence of caerulein, and also showed impaired glucose-stimulated insulin release. Thus, the effect of nicotinamide on the survival and function of B-cells is amplified by the presence of caerulein or IBMX.

1-Methyl-3-isobutylxanthine↗

PubMed2006

Localization of the extracellular matrix protein SC1 to synapses in the adult rat brain.

Extracellular matrix molecules play important roles in neural developmental processes such as axon guidance and synaptogenesis. When development is complete, many of these molecules are down-regulated, however the molecules that remain highly expressed are often involved in modulation of synaptic function. SC1 is an example of an extracellular matrix protein whose expression remains high in the adult rat brain. Confocal microscopy revealed that SC1 demonstrates a punctate pattern in synaptic enriched regions of the cerebral cortex and cerebellum. Higher resolution analysis using electron microscopy indicated that SC1 localizes to synapses, particularly the postsynaptic terminal. SC1 was also detected in perisynaptic glial processes that envelop synapses.

Animals↗

PubMed1990

Spatial organization of extracellular matrix and fibroblast activity: effects of serum, transforming growth factor beta, and fibronectin.

The goal of our research is to understand reciprocal relationships between cell function and tissue organization. We studied the regulation of fibroblast activity in an in vitro culture model that recapitulates in continuous fashion the cycle of events occurring during connective tissue repair. We present evidence that concomitant with spatial reorganization of the extracellular matrix, there was a dramatic decline in extracellular matrix synthesis and cell proliferation. Therefore, spatial reorganization was a crucial turning point for fibroblast activity. Factors that regulated the timing of spatial reorganization included serum, transforming growth factor beta, and fibronectin. By accelerating spatial reorganization of the cultures, transforming growth factor beta led to a relative decrease in cell proliferation and extracellular matrix synthesis. By retarding spatial reorganization of the cultures, fibronectin led to a relative increase in cell proliferation and extracellular matrix synthesis. The results indicate that spatial information in the three-dimensional cell-matrix interaction permits higher order, tissue-level regulation of fibroblast function.

Blood Proteins↗

PubMed1999

The biological behavior of autologous collagen-based extracellular matrix injected into the rabbit bladder wall.

Endoscopic techniques are providing a minimally invasive approach to the treatment of vesicoureteral reflux and urinary incontinence. Bovine collagen has been used, but potential degradation over time and sensitivity reactions have limited its usefulness. We evaluate the use of an autologous collagen-based extracellular matrix preparation injected within the rabbit bladder submucosa and compare it to the stability of bovine collagen-injected similarly. Of 28 New Zealand white rabbits, 12 underwent injection of autologous collagen-based extracellular matrix, 12 bovine collagen, and four normal saline sham injections into the anterior bladder submucosa. Twelve collagen specimens were iodinated with iodine 125 ((125)I) paraaminobenzoate reagent. The (125)I-labeled rabbits were monitored with a gamma camera to assess the level of decay of radioactivity over 12 weeks. All animals were killed 12 weeks post-injection. Assessment of radioactivity showed minimal difference in radioisotope labeling between the autologous and bovine collagen (total counts and decay kinetics). Compared to bovine collagen, the autologous collagen- based extracellular matrix implants histologically showed increased fibroblastic and vascular infiltration focally. The most significant histologic difference was the marked inflammatory response associated with the bovine collagen implants. These data suggest that in the short term, autologous and bovine collagen appear to have similar stability. The response to autologous collagen-based extracellular matrix may increase longevity of the implant, primarily by reducing immunologic rejection and improving biocompatibility within the host tissue. Further long-term studies are necessary to assess the long-term stability of autologous collagen-based extracellular matrix. Neurourol. Urodynam. 18:487-495, 1999.

Animals↗

PubMed1997

Regional variability in the time course of TGF-beta 1 expression, cellular proliferation and extracellular matrix expansion following arterial injury.

Transforming growth factor-beta 1 (TGF-beta 1) has been variably associated with the regulation of cellular proliferation and extracellular matrix expansion after arterial injury. We tested these associations in vivo in the rat carotid injury model. At 0, 3, 7, 14 and 28 days following arterial balloon injury, regional expression of TGF-beta 1 mRNA was assessed using in situ hybridization and the results compared to measures of cellular proliferation and extracellular matrix expansion. Both the TGF-beta 1 concentration measured in culture media of explanted carotid arteries and the quantitative in situ hybridization signal for TGF-beta 1 arterial media and neointima were maximal at 14 days after balloon injury. However, medial cellular proliferation was maximal at 3 days whereas neointimal proliferation was maximal at 14 days and significantly greater than medial proliferation. Neointimal cell density declined significantly between 7 and 14 days, indicating the expansion of extracellular matrix; however, medial cell density was unchanged between 3 and 28 days after balloon injury. Thus, differences in the regional arterial wall relationships between the time course of cellular proliferation, extracellular matrix expansion and the level of TGF-beta 1 expression demonstrate in vivo variability in the response to TGF-beta 1.

Angioplasty, Balloon, Coronary↗

PubMed1999

The perikaryal surface of spinal ganglion neurons: differences between domains in contact with satellite cells and in contact with the extracellular matrix.

The perikaryal surface of spinal ganglion neurons undergoes dynamic changes throughout life. In particular, numerous slender projections develop and retract continuously from this surface. We showed previously that the outgrowth of these projections, while an intrinsic property of spinal ganglion neurons, is also influenced by the surrounding microenvironment. Since the latter consists of satellite cells and the extracellular matrix, we sought to determine the relative contributions of each of these components to the outgrowth of perikaryal projections. To this end, we took advantage of a little known characteristic of the satellite cell sheaths: in the rabbit, these sheaths can exhibit gaps that leave the nerve cell body surface directly exposed to the extracellular matrix. We compared the surface domains covered by satellite cells with those in direct contact with the extracellular matrix. We found that the perikaryal projections are abundant in the former domains but are absent in the latter. We also found that the perineuronal extracellular matrix of rabbit spinal ganglia contains laminin and fibronectin, two glycoproteins that have been reported to promote the growth of axonal processes from sensory ganglion neurons. Laminin and fibronectin were also present at the level of the gaps in the satellite cell sheath. These results: (1) provide additional evidence that environmental factors influence the outgrowth of perikaryal projections from spinal ganglion neurons; (2) suggest that satellite cells permit the outgrowth of these projections; (3) suggest that in the spinal ganglia of adult rabbits the perineuronal extracellular matrix is not in itself able to promote the outgrowth of these projections. This study provides a further example of the influence that supporting neuroglial cells have on sensory ganglion neurons.

Animals↗

PubMedDate not supplied

Adhesion and migration of human glioma cells are differently dependent on extracellular matrix molecules.

To analyse the interactions between glioma cells and extracellular matrix (ECM) proteins, the adhesive and migratory capacity of five human glioma cell lines (D37MG, D54MG, GaMG, U118MG and U251MG) were studied. The expression of integrins was analysed and correlated to the adhesive and migratory abilities of the cells. All cell lines were able to adhere to and migrate on the extracellular matrix proteins collagen IV, fibronectin, laminin and vitronectin. Laminin was superior in propagating adhesion and migration in all five cell lines. As analysed by flow cytometry, the expression of the integrin subunits alpha 2, alpha 3, alpha 4, alpha 5, alpha 6, beta 3, beta 4, alpha v, and integrin alpha v beta 5 proved to be uniform between the cell lines. All integrins except alpha 4, alpha 6, beta 3 and beta 4 were expressed on more than 85% of the cells. Inhibition of adhesion with synthetic peptides and antibodies directed against integrins demonstrated that adhesion on laminin was independent of integrins and the 67 kD laminin receptor. On the other hand, migration was shown to be integrin-dependent on all substrates. The results indicate that the mechanism responsible for cell adhesion in human gliomas differ from those present during migration, and that integrins play an important role in regulating these two mechanisms.

Cell Adhesion↗

PubMed1997

Vasculogenesis and angiogenesis: extracellular matrix remodeling in coronary collateral arteries and the ischemic heart.

Heart failure secondary to ischemic cardiomyopathy is the primary cause of cardiovascular mortality. The promise of the collateral circulation lies in its potential to alter the course of the natural history of coronary heart disease. The collateral circulation of the heart is responsible for supplying blood and oxygen to the myocardium at ischemic risk following severe stenosis and reduced vasoelasticity function of a major coronary artery. In response to flow, stress, and pressure, collateral vessels are restructured and remodeled. Vascular remodeling by its very nature implies synthesis and degradation of extracellular matrix components in the vessel wall. Under normal physiological conditions proteinases that break down the specialized matrix are tightly regulated by antiproteinases. The balance between proteinase and antiproteinase influences is discoordinated during collateral development which leads to adaptive changes in the structure, function, and regulation of extracellular matrix components in the vessel wall. The role of extracellular matrix components in coronary collateral vessel formation in a canine model of chronic coronary artery occlusion has been demonstrated. The role of matrix proteinases and antiproteinases in the collateral vessel play a significant role in the underlying mechanisms of collateral development. This review presents new and significant information regarding the role of extracellular matrix proteinases and antiproteinases in vascular remodeling, function, and collateral development. Such information will have a significant impact on the understanding of the basic biology of the vascular extracellular matrix turnover, remodeling, and function as well as on elucidating potential avenues for pharmacological approaches designed to increase collateral formation and optimize myocardial blood flow in the treatment of ischemic heart disease.

Animals↗

PubMedDate not supplied

[Rearrangement of the morphological structure and degradation of the extracellular matrix in amphibian embryos after short-term disruption of cell contacts].

The changes in cell structure of explants of presumptive early gastrula mesoderm of Xenopus laevis and dynamics of extracellular matrix formation has been studied for 6 h after their isolation. After 6 h, control explants of any dorsoventral level turned into dense spheric homogeneous cell clusters. Explants of dorsal and lateral sectors, treated with medium without Ca2+ and Mg2+ for 30 s, bent and separated into several layers, and in ventral sector explants, cavities, surrounded by polarized cells, arose. In control explants, the amount of extracellular matrix on the surface and in intercellular spaces increased, and in the experimental explants, extracellular matrix disappeared and was not observed for several hours. Previously described differential transformations of the treated explants (Georgiev, Belousov, 1986) are supposed to be determined by extracellular matrix degradation and the degradation-associated complications of cell structure of the explant.

Animals↗