SEARCH · PubMed Health

Results for “Extracellular Matrix”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,063 records · Page 59Linked to original sources

PubMed1989

The extracellular matrix of the human optic nerve.

The nerve fibers of the optic nerve are enclosed and segmented by extracellular matrix. With immunostains, we localized collagen types I through VI, laminin, and fibronectin in frozen sections of the extracellular matrix of the prelaminar, laminar, and retrolaminar human optic nerve. The internal limiting lamina of the optic nerve has an extracellular composition similar to the thicker adjacent retinal internal limiting lamina. We confirmed that the lamina cribrosa contains type IV collagen and laminin, whereas the sclera does not. The septa of the retrolaminar optic nerve appear as vascular inward extensions of the pia mater. The glial tube that lines the optic nerve extends forward from the retrolaminar optic nerve through the lamina cribrosa to end anteriorly at the retinal pigment epithelium. It does not separate the optic nerve from the adjacent sensory retina.

Aged↗

PubMed1994

Biochemical and structural analyses of the extracellular matrix fibrils of Myxococcus xanthus.

It is characteristic of myxobacteria to produce large amounts of extracellular material. This report demonstrates that this material in Myxococcus xanthus is fibrillar and describes the structure and chemical composition of the fibrils. The extracellular matrix fibrils are the mediators of cell-cell cohesion in M. xanthus. As such, the fibrils play an important role in the cell-cell interactions that form the basis for the social and developmental lifestyle of this organism. The fibrils are composed of protein and carbohydrate in a 1.0:1.2 ratio. Combined, the two fractions accounted for greater than 85% of the mass of isolated fibrils, and the fibrils were found to compose up to 10% of the dry weight of cells grown at high density on a solid surface. The polysaccharide portion of the fibrils was shown to be composed of five different monosaccharides: galactose, glucosamine, glucose, rhamnose, and xylose. Glucosamine, one of the component monosaccharides of the fibrils and a known morphogen for M. xanthus, inhibited cohesion to a level near that of Congo red (the positive control for cohesion inhibition). Glucose and xylose also inhibited cohesion but less than did glucosamine. Analysis of the morphology of the fibrils, the periodicities within the distribution of fibril diameters observed by field emission scanning electron microscopy, and the observation of fibrils on hydrated cells strongly suggested that the extracellular matrix of M. xanthus was indeed arranged as fibrils. Furthermore, results suggested that the fibrils were constructed as carbohydrate structures with associated proteins.

Bacterial Adhesion↗

PubMed2004

Cell surface localization of heparanase on macrophages regulates degradation of extracellular matrix heparan sulfate.

Extravasation of peripheral blood monocytes through vascular basement membranes requires degradation of extracellular matrix components including heparan sulfate proteoglycans (HSPGs). Heparanase, the heparan sulfate-specific endo-beta-glucuronidase, has previously been shown to be a key enzyme in melanoma invasion, yet its involvement in monocyte extravasation has not been elucidated. We examined a potential regulatory mechanism of heparanase in HSPG degradation and transmigration through basement membranes in leukocyte trafficking using human promonocytic leukemia U937 and THP-1 cells. PMA-treated cells were shown to degrade 35S-sulfated HSPG in endothelial extracellular matrix into fragments of an approximate molecular mass of 5 kDa. This was not found with untreated cells. The gene expression levels of heparanase or the enzyme activity of the amount of cell lysates were no different between untreated and treated cells. Immunocytochemical staining with anti-heparanase mAb revealed pericellular distribution of heparanase in PMA-treated cells but not in untreated cells. Cell surface heparanase capped into a restricted area on PMA-treated cells when they were allowed to adhere. Addition of a chemoattractant fMLP induced polarization of the PMA-treated cells and heparanase redistribution at the leading edge of migration. Therefore a major regulatory process of heparanase activity in the cells seems to be surface expression and capping of the enzyme. Addition of the anti-heparanase Ab significantly inhibited enzymatic activity and transmigration of the PMA-treated cells, suggesting that the cell surface redistribution of heparanase is involved in monocyte extravasation through basement membranes.

Animals↗

PubMed1994

Effects of tretinoin tocoferil on gene expression of the extracellular matrix components in human dermal fibroblasts in vitro.

Recently, it has been reported that tretinoin tocoferil (TT), a synthesized ester-bond compound of all-trans-retinoic acid and alpha-tocopherol, accelerates the formation of granuloma and is effective in promoting experimental open skin wound healing. To investigate whether TT affects the gene expression of extracellular matrix components of human dermal fibroblasts, we measured the mRNA levels of various extracellular matrix components of fibroblasts incubated with TT using specific cDNA probes. The mRNA levels of elastin increased up to 30% of the controls and those of collagen III and VI up to 60%. The mRNA levels of collagen I and fibronectin remarkably increased up to 90% of the controls. These results suggest that the stimulatory effect of TT on the gene expression of many extracellular matrix components might be one of the mechanisms of its promotion of wound healing.

Actins↗

PubMed1991

Changes in extracellular matrix materials in the uterine myometrium of rats during pregnancy and postparturition.

Morphological changes in extracellular matrix materials in the uterine myometrium of rats during pregnancy and postparturition were studied by light and electron microscopy together with immunofluorescence microscopy for type III and IV collagens, fibronectin and laminin. The main components present in late pregnancy were 1) various-sized collagen fibrils, 2) thick elastic fibers adjacent to smooth muscle cells, and 3) continuous and thick basement membranes of hypertrophic smooth muscle cells. These findings are considered to indicate degradation of collagen fibrils and development of elastic fibers and basement membranes of smooth muscle cells. This change in extracellular matrix materials in the late stage of pregnancy may be important in the process of uterine enlargement associated with elasticity and preparation for labor. In the postpartum stage, myofibroblastic interstitial cells were seen to phagocytize collagen fibrils, and elastic fibers accumulated mainly around the bundles of smooth muscle cells. These changes in the postpartum stage are thought to be important for the process in which the uterus returns to the nonpregnant condition. It is suggested that smooth muscle cells participate in regulating the development of their basement membranes and elastic fibers, and that myofibroblastic interstitial cells function by clearing degraded collagen fibrils from the uterine myometrium.

Animals↗

PubMed1993

Hyaluronic acid and hyaluronic acid-binding proteins in brain extracellular matrix.

Hyaluronic acid (HA) plays the main structural role in the formation of brain extracellular matrix (ECM). The extracellular space appears empty by electron microscopy because HA is readily dissolved during the preparation of tissues for ultrastructural studies. The HA-binding proteins so far identified in brain ECM are versican, aggrecan and the glial HA-binding protein. Versican is a large fibroblast proteoglycan preferentially expressed in embryonic cartilage at the time of mesenchymal condensation. Glial HA-binding protein (GHAP) is probably a proteolytic product of versican corresponding to its HA-binding amino-terminal domain. It is mainly a white-matter protein, suggesting that the proteinase responsible for its cleavage from versican is normally activated in this location. Versican is found in both white matter and gray matter, where it forms pericellular coats around large neurons. Aggrecan, the aggregating proteoglycan of mature cartilage, co-localizes with versican in this location. In white matter, the localization of GHAP and versican is identical to that of the glial fibrillary acid protein, suggesting that both proteins are produced by astrocytes. An important difference between GHAP and versican is that GHAP but not versican is released from the tissues by hyaluronidase digestion, which suggests that versican is anchored to the cell membranes lining the extracellular space. GHAP was localized at the ultrastructural level in the granule cell layer of rat cerebellum, the only region of gray matter that is positive for GHAP in this species. Rats were perfused with aqueous fixatives containing cetylpyridinium chloride or tannic acid to prevent the solubilization of HA. GHAP is found throughout the extracellular space, the synaptic clefts being a notable exception. GHAP appears late in development, and the same is true for versican, the characteristic perineuronal coats first becoming apparent in the third postnatal week. It is suggested that a marked change occurs in the structure of brain ECM when HA-binding proteins first appear, and that the change is similar to that observed in prechondrogenic mesenchyme, i.e., reduction of the extracellular space and cell aggregation.

Animals↗

PubMed1994

Alterations in renal tubular extracellular matrix components after ischemia-reperfusion injury to the kidney.

BACKGROUND: The kidney is unique in that after ischemic injury to the renal tubules, essentially complete regenerative repair can occur. However, the factors responsible for renal regeneration are poorly delineated. Despite the importance of extracellular matrix components in cell attachment, proliferation, migration, and differentiation (all potentially important factors in regeneration), alterations in renal tubular extracellular matrix components after renal ischemia-reperfusion injury have not been examined. EXPERIMENTAL DESIGN: Rats were subjected to bilateral renal pedicle clamping for 45 minutes and kidneys were taken at various time points for light microscopy and laminin, fibronectin and collagen IV immunofluorescence examination. Blood was taken for plasma urea nitrogen and creatinine determination. RESULTS: Plasma creatinine and urea nitrogen rose rapidly peaking on days 1 to 3 (peak creatinine 3.2 +/- 0.3 mg/dl). The corticomedullary junction showed severe tubular necrosis and desquamation. Renal corticomedullary tubular basement membrane laminin showed a dramatic decrease at 18 hours through 24 to 48 hours postischemia-reperfusion injury, followed by a marked increase through day 5. Fibronectin increased markedly at 4 hours in all areas of the kidney and this continued through day 5. Type IV collagen remained unchanged at all time points examined. CONCLUSIONS: This study documents alterations in renal tubular basement membrane laminin and fibronectin after renal ischemia-reperfusion injury. The ability of the extracellular matrix to modulate cell functions of potential importance in regeneration suggests that the alterations described may play a role in renal tubular regeneration after ischemic acute tubular necrosis.

Animals↗

PubMed1999

Antibodies to CD18 influence neutrophil migration through extracellular matrix.

Mac-1 (CD11b/CD18) is known to be involved in neutrophil (PMN) adhesion to endothelial cells and extracellular matrix. Although antibodies to CD 18 are being tested for therapy in humans, their role in PMN migration through the extracellular matrix is unknown. We used direct visualization to quantify PMN motility through reconstituted, three-dimensional gels of collagen type I. Gels were prepared with different concentrations of collagen (ranging from 0.1 to 1.0 mg/mL) and PMN migration was examined in the presence and absence of antibodies to CD18 (anti-CD18), with and without stimulation by N-formyl peptides. In low-concentration gels (<0.6 mg/mL), anti-CD18 had a significant influence on PMN migration, increasing motility in unstimulated PMN by 90% at 0.3 mg/mL collagen, and decreasing motility in N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated PMN by 70% at 0.4 mg/mL collagen. But antiCD18 had no effect on the rate of cell migration through high-concentration collagen gels (>0.6 mg/mL). PMN migration through collagen gels is CD18-dependent but only under conditions of high hydration, suggesting that CD18-mediated effects (e.g., adhesion to gel fibers) are only important when the fiber density is relatively low. Anti-CD18 inhibited, but did not eliminate, the adhesion of fMLP-stimulated PMN to the surface of collagen gels, suggesting that cells use multiple mechanisms for gaining traction within the gel. Because of the multiple modes of interaction between motile cells and the deformable fiber matrix, blockade of one component, such as CD18, can enhance the rate of cell migration under one set of conditions, and inhibit under another.

Antibodies↗

PubMed1998

Differential expression of flectin in the extracellular matrix and left-right asymmetry in mouse embryonic heart during looping stages.

A novel extracellular matrix protein flectin (250 kD M(r)) shows specific left-right asymmetric expression before and throughout the looping process during heart development in avian embryos [Tsuda et al., 1996]. Flectin is a candidate molecule to provide directionality to the looping process in the avian model. In this study on mouse embryonic heart development, flectin is shown to be developmentally regulated and to be expressed in a specific asymmetric fashion, but in a different pattern from that observed in avian hearts. The molecules involved in development tend to be the same, but timing of expression, modulation, and asymmetry are different. In the mouse embryo, flectin is expressed symmetrically when the cardiogenic plate is formed. As looping progresses, flectin expression becomes asymmetric. There is right side predominance at the outflow tract and left side predominance at the ventricular portion of the tubular heart. The left side predominance of flectin develops in an anteroposterior direction, while right side predominance of the outflow tract remains relatively unchanged. These differential expression patterns of flectin decrease once the looping process is completed. After looping, flectin becomes restricted to the epicardium and subepicardial extracellular regions. In inv/inv mice, a known mouse model for human situs inversus, in which the directionality of heart looping is inverted, flectin expression pattern is mirror image of that of normal mouse embryos during looping stages. Our study indicates that, in the mouse, flectin shows a specific asymmetric expression pattern after initiation of heart looping and that this asymmetric expression pattern is related to the directionality of looping. The remodeling of the extracellular matrix (ECM) including specific flectin expression begins with the looping process. This morphogenetic change of the ECM coincides with the differentiation of each region of the tubular heart.

Animals↗

PubMed2005

Extracellular matrix remodeling by human granzyme B via cleavage of vitronectin, fibronectin, and laminin.

Human granzyme B (GrB) released from cytotoxic lymphocytes plays a key role in the induction of target cell apoptosis when internalized in the presence of perforin. Here we demonstrate that GrB also possesses a potent extracellular matrix remodeling activity. Both native and recombinant GrB caused detachment of immortalized and transformed cell lines, primary endothelial cells, and chondrocytes. Cell detachment by GrB induced endothelial cell death (anoikis). GrB also inhibited tumor cell spreading, migration, and invasion in vitro. Investigation into the underlying mechanism revealed that GrB efficiently cleaves three proteins involved in extracellular matrix structure and function: vitronectin, fibronectin, and laminin. In vitronectin, GrB cleaves after an Arg-Lys-Asp (RGD) motif, which is part of the integrin-binding site found in matrix proteins. We propose that targeting of the integrin-extracellular matrix interface by GrB may allow perforin-independent killing of target cells via anoikis, restrict motility of tumor cells, facilitate lymphocyte migration, or directly reduce virus infectivity. It may also contribute to tissue destruction in diseases in which extracellular GrB is evident, such as rheumatoid arthritis and atherosclerosis.

Arteriosclerosis↗

PubMed1999

Ultrastructure and immunohistochemical identification of the extracellular matrix of the chinchilla cochlea.

The molecular composition and three-dimensional organization of the extracellular matrix (ECM) was studied by immunofluorescent microscopy, transmission and scanning electron microscopy in three connective tissue structures of the cochlea: the spiral limbus, basilar membrane and spiral ligament. Type II collagen, fibronectin, tenascin, chondroitin sulfate proteoglycans, alphav and beta1 integrins were immunolocalized in the ECM of these connective tissue structures. Electron micrographs showed a continuum of cross-striated collagen fibrils having a similar diameter and axial periodicity that spread from the spiral limbus via the basilar membrane and into the spiral ligament. Some of collagen fibrils were aggregated laterally into bundles. Bundle images, and their digital Fourier transformations, showed a major 67-nm axial D-repeat characteristic for collagen fibrils. Transmission electron microscopy showed numerous proteoglycans associated with the collagen fibrils. The spiral limbus, basilar membrane and spiral ligament demonstrated regional differences in molecular composition and structural organization of their ECM. The glycoproteins fibronectin, tenascin and alphav integrin were immunolocalized mainly in the basilar membrane. Collagen fibrils of the spiral limbus and spiral ligament did not appear to be strongly oriented. However, most of the collagen fibrils in the basilar membrane were arranged into radially directed bundles. Collagen fibrils in the basilar membrane were also surrounded by a homogeneous matrix, which was immunoreactive to fibronectin and tenascin antibodies. A more complete understanding of the composition and structural organization of the ECM in these connective tissue structures in the cochlea provides a foundation upon which micromechanical models of cochlear function can be constructed.

Animals↗

PubMed2005

Cell adhesion ability of artificial extracellular matrix proteins containing a long repetitive Arg-Gly-Asp sequence.

We generated recombinant artificial extracellular matrix (ECM) proteins containing repetitive Arg-Gly-Asp (RGD) sequences: double (RGD2), 21 (RGD21) and 43 (RGD43) repeats of RGD. RGD43-coated glass slides promoted fibroblast NIH3T3 cell adhesion and spreading on the surface. Since actin stress fibers and focal contacts were also observed in cells adhering on RGD43-coated glass slides, it was suggested that the RGD peptides in RGD43 transmitted an adhesion signal via integrins and promoted cell adhesion. We coated recombinant ECM proteins, each containing repetitive RGD domains, on polystyrene plates and investigated the effects of RGD length on the cell adhesion ability using three different cell lines, namely, fibroblast NIH3T3, HeLa cancer and neuronal PC12 cell lines. The results indicated that RGD43 had a cell adhesion ability superior to those of natural extracellular matrix proteins, fibronectin and laminin, although the effects of RGD repeat length on the cell adhesion ability depended on the cell line. As an artificial three-dimensional scaffold for cell cultivation, we also prepared an RGD43 hydrogel by a cross-linking reaction using glutaraldehyde. On the RGD43 hydrogel scaffold, fibroblast cells also successfully adhered under serum-free conditions.

Animals↗

PubMed2000

27 kDa extracellular matrix protein revealed by a monoclonal antibody raised against rat testis.

In search of unique components of the seminiferous tubule extracellular matrix, monoclonal antibodies were raised against an isolated seminiferous tubule extracellular matrix, and the monoclonal antibody 12G11 was cloned. By immunofluorescence microscopy in eight kinds of rat tissues (testis, lung, liver, small intestine, cardiac muscle, skeletal muscle, kidney, and brain), 12G11 antigen existed only in the testis. Immunoelectron microscopy revealed that the antigen is localized in the basement membrane of the seminiferous tubule and in the basement membranes of myoid cells. For a biochemical analysis, eight kinds of rat extracellular matrices were isolated and solubilized with 8 M urea and 2% beta-mercaptoethanol. Immunoblot analysis of these samples in 0.8% agarose gel also showed that the antigen was specific for the testis, and in a two high-molecular weight aggregates. These aggregates seemed to contain type IV collagen and laminin chains. The antigen of 12G11 antibody was shown to be 27 kDa by 10% SDS-PAGE followed by immunoblotting. From these data, the existence of a testis specific 27 kDa basement membrane protein, which associate with type IV collagen and laminin, was suggested.

Animals↗

PubMed2003

Klebsiella pneumoniae MrkD-mediated biofilm formation on extracellular matrix- and collagen-coated surfaces.

The type 3 fimbriae of Klebsiella pneumoniae are comprised of the major fimbrial subunit (MrkA) and the adhesin (MrkD) that has previously been shown to mediate binding to collagen. The ability of adhesive and non-adhesive derivatives of K. pneumoniae to form biofilms on collagen-coated surfaces in continuous-flow chambers was investigated. Unlike biofilm formation on abiotic plastic surfaces, the presence of the MrkD adhesin was necessary for growth on collagen-coated surfaces. Fimbriate strains lacking the MrkD adhesin did not efficiently adhere to and grow on these surfaces. Similarly, purified human extracellular matrix and the extracellular matrix formed by human bronchial epithelial cells grown in vitro provided a suitable substrate for MrkD-mediated biofilm formation, whereas direct binding to the respiratory cells was not observed. Type 3 fimbriae may therefore have two roles in the early stages of adherence and growth on in-dwelling devices such as endotracheal tubes. The MrkA polypeptide could facilitate adsorption to abiotic polymers of recently implanted devices and the MrkD adhesin could enable bacteria to adhere to and grow on polymers coated with host-derived proteins.

Adhesins, Bacterial↗

PubMed2006

Extracellular matrix of the cumulus-oocyte complex.

The mammalian oocyte is surrounded by several layers of cumulus granulosa cells that nurture the oocyte during its development and actively participate in the process of ovulation. After the ovulatory luteinizing hormone surge, a distinctive program of extracellular matrix production is initiated in the cumulus-oocyte complex. This process known as cumulus expansion or mucification involves synthesis of a backbone of long hyaluronan oligosaccharide chains that are cross-linked by a complex of hyaluronan binding cell surface and extracellular matrix proteins and proteoglycans. Active components of the cumulus matrix are synthesized directly by cumulus cells under the control of endocrine- and oocyte-derived factors, secreted by mural granulosa cells, or enter the follicle in blood plasma. Appropriate composition and assembly of the cumulus matrix is essential for ovulation, efficient passage of the oocyte through the oviduct, and for fertilization. This review describes the critical components and their functional roles in the cumulus matrix, as well as the molecular regulation of cumulus matrix gene expression.

Animals↗

PubMed1995

Thrombospondin modulates adhesion, proliferation and production of extracellular matrix in mesangial cells.

Thrombospondin (TSP) is produced by glomerular mesangial cells and one of the extracellular matrix in the mesangium, whereas the physiological role of TSP in mesangial cells is poorly understood. In order to know whether TSP modulates mesangial cell functions, we investigated the effects of TSP on cell adhesion, proliferation, synthesis of extracellular matrix and serine proteinases in cultured human mesangial cells. The substratum of TSP inhibited cell attachment and spreading in a TSP-dose-dependent manner in mesangial cells. Soluble TSP (50 micrograms/ml) also caused the detachment of fully adherent mesangial cells, whereas TSP less than 10 micrograms/ml did not. [3H]-thymidine incorporation into mesangial cells was dose-dependently reduced by TSP. On the other hand, the production of both fibronectin and type IV collagen from mesangial cells was enhanced by TSP. The incubation of mesangial cells with TSP increased the secretion of tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA), while plasminogen activator inhibitor-type 1 (PAI-1) decreased. These observations indicate that TSP inhibits cell adhesion and proliferation in cultured human mesangial cells. It is also suggested that TSP influences the metabolism of mesangial matrix by modulating both synthesis and degradation of matrix components. Thus, TSP, may be an important mediator of mesangial cell functions in an autocrine fashion.

Cell Adhesion↗

PubMed2003

Lung epithelial cells and extracellular matrix components induce expression of Pneumocystis carinii STE20, a gene complementing the mating and pseudohyphal growth defects of STE20 mutant yeast.

Pneumocystis carinii causes severe pneumonia in immunocompromised hosts. The binding of P. carinii to alveolar epithelial cells and extracellular matrix constituents such as fibronectin and vitronectin is a central feature of infection, which initiates proliferation of the organism. Herein, we demonstrate that P. carinii binding to lung cells specifically alters the gene expression of the organism, regulating fungal growth. Subtractive hybridization was performed to isolate P. carinii genes expressed following binding to mammalian extracellular matrix constituents. P. carinii STE20 (PCSTE20), a gene participating in mating and pseudohyphal growth of other fungi, was identified following adherence to the extracellular matrix constituents fibronectin, vitronectin, collagen, and lung epithelial cells. The expression of PCSTE20 and a related P. carinii mitogen-activated protein kinase (MAPK) kinase gene, also implicated in signaling of mating, were both specifically upregulated by binding to matrix protein. The expression of general cyclin-dependent kinases and other MAPKs not involved in mating pathways were not altered by organism binding. PCSTE20 expression was also strongly enhanced following organism attachment to A549 lung epithelial cells. When expressed in a Saccharomyces cerevisiae ste20Delta mutant, PCSTE20 suppressed defects in both mating and pseudohyphal growth. These findings are consistent with the observed proliferation and filopodial extension of Pneumocystis organisms adherent to the epithelium in the lungs of immunocompromised hosts. PCSTE20 expression appears to represent a significant component in the regulation of the life cycle of this intractable opportunistic pathogen.

Amino Acid Sequence↗

PubMed2005

Influence of cyclical mechanical strain on extracellular matrix gene expression in human lamina cribrosa cells in vitro.

PURPOSE: The mechanical effect of raised intraocular pressure is a recognised stimulus for optic neuropathy in primary open angle glaucoma (POAG). Characteristic extracellular matrix (ECM) remodelling accompanies axonal damage in the lamina cribrosa (LC) of the optic nerve head in POAG. Glial cells in the lamina cribrosa may play a role in this process but the precise cellular responses to mechanical forces in this region are unknown. The authors examined global gene expression profiles in lamina cribrosa cells exposed to cyclical mechanical stretch, with an emphasis on ECM genes. METHODS: Glial fibrillary acid protein negative primary LC cells were generated from the optic nerve head tissue of three normal human donors. Confluent cell passages (n=4) were exposed to 15% stretch at 1 Hz or static conditions for 24 h using the Flexercell system. Gene expression was assessed using Affymetrix U133A microarrays with pooled RNA. Expression levels were normalized using robust multi-chip average (RMA). Expression data was annotated using NIH DAVID software. ECM-related gene expression was validated in an independent experiment using quantitative real-time PCR and protein synthesis was measured using ELISA and immunohistochemistry. RESULTS: Compared with static controls, 805 genes were upregulated and 644 were downregulated by +/-1.5 fold in stretched LC cells. Gene ontologies included ECM, cell proliferation, growth factor activity, and signal transduction. Differentially expressed ECM genes included elastin, collagens (IV, VI, VIII, IX), thrombospondin 1, perlecan, and lysl oxidase. Quantitative PCR demonstrated that the expression of TGF-beta2, BMP-7, elastin, collagen VI, biglycan, versican, EMMPRIN, VEGF, and thrombomodulin were reproducible and consistent with the microarray data. VEGF and TGF-beta2 protein levels were also significantly (p<0.05) increased in stretched cell media supernatants. Immunohistochemistry demonstrated increased EMMPRIN (an extracellular matrix metalloproteinase inducer) protein in human POAG optic nerve head tissue compared to nonglaucomatous controls. CONCLUSIONS: These findings demonstrate that LC cells respond to mechanical stimuli in vitro by transcription of several components and modulators of the ECM. Some of the upregulated ECM genes identified are novel in the context of glaucomatous optic neuropathy (biglycan, versican, EMMPRIN, and BMP-7). The LC cell may represent both an important pro-fibrotic cell type in the optic nerve head and an attractive target for novel therapeutic intervention in POAG.

Cells, Cultured↗