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Extracellular Matrix (extracellular + matrix)
Kinds of Extracellular Matrix Terms modified by Extracellular Matrix Selected AbstractsTissue Engineering: Scaffold-Mediated 2D Cellular Orientations for Construction of Three Dimensionally Engineered Tissues Composed of Oriented Cells and Extracellular Matrices (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 7 2009Mater. Novel technology for fabrication of 3D-engineered tissues consisting of oriented cells and extracellular matrices (ECM) is described by Yoshida and co-workers on page 1001. They prepare disulfide-crosslinked hydrogels with oriented pores to induce cellular orientations on and in the scaffolds. Finally, 3D-oriented engineered tissues with 2D-cell and ECM orientation are successfully obtained by decomposing template gel with reductant agent. [source] Scaffold-Mediated 2D Cellular Orientations for Construction of Three Dimensionally Engineered Tissues Composed of Oriented Cells and Extracellular MatricesADVANCED FUNCTIONAL MATERIALS, Issue 7 2009Hiroaki Yoshida Abstract Various hydrogels, such as poly(, -glutamic acid) (, -PGA), gelatin (GT), alginic acid (Alg), and agarose (Aga), with 3D interconnected and oriented fibrous pores (OP gels) are prepared for 3D polymeric cellular scaffolds by using silica fiber cloth (SC) as template. After the preparation of these hydrogels with the SC templates, the latter are subsequently removed by washing with hydrofluoric acid solution. Scanning electron microscopy (SEM) clearly shows OP structures in the hydrogels. These various types of OP gels are successfully prepared in this way, independently of the crosslinking mechanism, such as chemical (, -PGA or GT), coordinate-bonded (Alg), or hydrogen-bonded (Aga) crosslinks. SEM, confocal laser scanning microscopy, and histological evaluations clearly demonstrate that mouse L929 fibroblast cells adhere to and extend along these OP structures on/in , -PGA hydrogels during 3D cell culture. The L929 cells that adhere on/in the oriented hydrogel are viable and proliferative. Furthermore, 3D engineered tissues, composed of the oriented cells and extracellular matrices (ECM) produced by the cells, are constructed in vitro by subsequent decomposition of the hydrogel with cysteine after 14 days of cell culture. This novel technology to fabricate 3D-engineered tissues, consisting of oriented cells and ECM, will be useful for tissue engineering. [source] Dynamic Hydrogels: Switching of 3D Microenvironments Using Two-Component Naturally Derived Extracellular Matrices (Adv. Mater.ADVANCED MATERIALS, Issue 6 20106/2010) The front cover image depicts a two-component extracellular matrix (ECM) in which one component acts as a stable structural element (which supports cell attachment and migration) and another component gels or dissolves reversibly (a modulatory component). Samuel K. Sia and co-workers show on p. 686 that by dynamically adding or removing crosslinks in the modulatory component, properties of the composite ECM, such as the ability of cells to migrate and the rate of diffusive transport, can be altered. [source] Dynamic Hydrogels: Switching of 3D Microenvironments Using Two-Component Naturally Derived Extracellular MatricesADVANCED MATERIALS, Issue 6 2010Brian M. Gillette This article describes fabrication of a two-component extracellular matrix (ECM) in which one component acts as a stable structural element and another component gels or dissolves reversibly (a modulatory component). Using a composite collagen-alginate ECM, reversible crosslinking of the alginate (the modulatory component) via application of calcium or citrate modulates cell mobility in a 3D collagen matrix (the structural component). [source] A Versatile Synthetic Extracellular Matrix Mimic via Thiol-Norbornene PhotopolymerizationADVANCED MATERIALS, Issue 48 2009Benjamin D. Fairbanks Step-growth, radically mediated thiol-norbornene photopolymerization is used to create versatile, stimuli-responsive poly(ethylene glycol)-co-peptide hydrogels (see image) The reaction is cytocompatible and allows for the encapsulation of human mesenchymal stem cells with a viability greater than 95%. Cellular spreading is dictated via three-dimensional biochemical photopatterning. [source] Dispatches from the Last Frontier of Molecular and Cell Biology: Biosynthesis of Polysaccharides and Proteoglycans of the Cell Surface and Extracellular MatrixIUBMB LIFE, Issue 4 2002Bruce Stone No abstract is available for this article. [source] Mechanically Strained Cells of the Osteoblast Lineage Organize Their Extracellular Matrix Through Unique Sites of ,V,3 -Integrin ExpressionJOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2000Magdalena Wozniak Abstract Bone cells transduce mechanical signals into anabolic biochemical responses. However, the mechanisms of mechanotransduction are unknown. To address this issue, we performed studies in primary cells of the human osteoblast lineage grown on collagen/vitronectin-coated supports. We discovered that mechanical strain stimulated a redistribution of the ,v,3 -integrin to irregular plaque-like areas at the cell-extracellular matrix surface. Proteins involved in integrin-matrix interactions in focal adhesions, vinculin and talin, did not localize to the plaque-like areas of ,v,3 -expression, but signaling molecules such as focal adhesion kinase (FAK) did. Mechanical strain increased the number and size of the plaques defined by surface expression of ,v,3 -integrin. Osteopontin was secreted as a cross-linked macromolecular complex, likely through the action of tissue transglutaminase that also was found in the plaques of ,v,3 -integrin cell-matrix interaction. Mechanical strain increased mineralization of the extracellular matrix that developed in these plaques in ,v,3 -integrin-dependent manner. Because the plaque-like areas of cell-matrix interaction exhibit macromolecular assembly and mineralization, we conclude that they may represent subcellular domains of bone formation and that ,v,3 -integrin activation represents one mechanism by which mechanical strain stimulates bone formation. [source] The Role of the Extracellular Matrix in Tissue Distribution of Macromolecules in Normal and Pathological Tissues: Potential Therapeutic ConsequencesMICROCIRCULATION, Issue 4 2008Helge Wiig ABSTRACT The interstitial space is a dynamic microenvironment that consists of interstitial fluid and structural molecules of the extracellular matrix, such as glycosaminoglycans (hyaluronan and proteoglycans) and collagen. Macromolecules can distribute in the interstitium only in those spaces unoccupied by structural components, a phenomenon called interstitial exclusion. The exclusion phenomenon has direct consequences for plasma volume regulation. Early studies have assigned a major role to collagen as an excluding agent that accounts for the sterical (geometrical) exclusion. More recently, it has been shown that the contribution of negatively charged glycosaminoglycans might also be significant, resulting in an additional electrostatical exclusion effect. This charge effect may be of importance for drug uptake and suggests that either the glycosaminoglycans or the net charge of macromolecular substances to be delivered may be targeted to increase the available volume and uptake of macromolecular therapeutic agents in tumor tissue. Here, we provide an overview of the structural components of the interstitium and discuss the importance the sterical and electrostatical components have on the dynamics of transcapillary fluid exchange. [source] Photosynthetic Eukaryotes of Freshwater Wetland Biofilms: Adaptations and Structural Characteristics of the Extracellular Matrix in the Green Alga, Cosmarium reniforme (Zygnematophyceae, Streptophyta)THE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 4 2009DAVID S. DOMOZYCH ABSTRACT. Cosmarium reniforme (Zygnematophyceae, Streptophyta) is a green alga that is commonly found in biofilms of wetlands of the Adirondack region, NY (USA). Two distinctive characteristics that are critical to this alga's survival in a benthic biofilm are its elaborate cell morphology and extracellular matrix (ECM). In this study, ultrastructural, immunocytochemical, and experimental methodologies were employed in order to elucidate the cellular characteristics that are critical for survival in a biofilm. The ECM consists of a thick, outwardly lobed cell wall (CW), which contains a patterned network of structurally complex pores. Each pore consists of a narrow channel, terminating internally at a bulb that invaginates localized regions of the plasma membrane. The outer region of the pore contains arabinogalactan protein-like and extensin epitopes that are likely involved in adhesion mechanisms of the cell. External to the CW is the extracellular polymeric substance that is employed in ensheathment of the cell to the substrate and in gliding motility. The architectural design/biochemical make-up of the CW and a secretory system that encompasses the coordinated activities of the endomembrane and cytomotile/cytoskeletal systems provide the organism with effective mechanisms to support life within the biofilm complex. [source] Laminin and fibronectin modulate inner ear spiral ganglion neurite outgrowth in an in vitro alternate choice assayDEVELOPMENTAL NEUROBIOLOGY, Issue 13 2007Amaretta R. Evans Abstract Extracellular matrix (ECM) molecules have been shown to function as cues for neurite guidance in various populations of neurons. Here we show that laminin (LN) and fibronectin (FN) presented in stripe micro-patterns can provide guidance cues to neonatal (P5) inner ear spiral ganglion (SG) neurites. The response to both ECM molecules was dose-dependent. In a LN versus poly- L -lysine (PLL) assay, neurites were more often observed on PLL at low coating concentrations (5 and 10 ,g/mL), while they were more often on LN at a high concentration (80 ,g/mL). In a FN versus PLL assay, neurites were more often on PLL than on FN stripes at high coating concentrations (40 and 80 ,g/mL). In a direct competition between LN and FN, neurites were observed on LN significantly more often than on FN at both 10 and 40 ,g/mL. The data suggest a preference by SG neurites for LN at high concentrations, as well as avoidance of both LN at low and FN at high concentrations. The results also support a potential model for neurite guidance in the developing inner ear in vivo. LN, in the SG and osseus spiral lamina may promote SG dendrite growth toward the organ of Corti. Within the organ of Corti, lower concentrations of LN may slow neurite growth, with FN beneath each row of hair cells providing a stop or avoidance signal. This could allow growth cone filopodia increased time to sample their cellular targets, or direct the fibers upward toward the hair cells. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007 [source] Remodeling of extracellular matrix and epileptogenesisEPILEPSIA, Issue 2010Alexander Dityatev Summary Extracellular matrix (ECM) in the brain is composed of molecules synthesized and secreted by neurons and glial cells, which form stable aggregates of diverse composition in the extracellular space. In the mature brain, ECM undergoes a slow turnover and restrains structural plasticity while supporting multiple physiologic processes, including perisomatic ,-aminobutyric acid (GABA)ergic inhibition, synaptic plasticity, and homeostatic regulations. Seizures lead to striking remodeling of ECM, which may be essentially engaged in different aspects of epileptogenesis. This view is supported by human genetic studies linking ECM molecules and epilepsy, by data showing altered epileptogenesis in mice deficient in ECM molecules, and by evidence that ECM may shape seizure-induced sprouting of mossy fibers, granule cell dispersion, and astrogliosis. Therefore, restraining seizure-induced remodeling of ECM or suppressing the signaling triggered by the remodeled ECM might provide effective therapeutic strategies to antagonize the progression of epileptogenesis. [source] A BAC transgenic mouse model to analyze the function of astroglial SPARCL1 (SC1) in the central nervous systemGLIA, Issue 9 2008Jill M. Weimer Abstract Extracellular matrix associated Sparc-like 1 (SC1/SPARCL1) can influence the function of astroglial cells in the developing and mature central nervous system (CNS). To examine SC1's significance in the CNS, we generated a BAC transgenic mouse model in which Sc1 is expressed in radial glia and their astrocyte derivatives using the astroglial-specific Blbp (Brain-lipid binding protein; [Feng et al., (1994) Neuron 12:895,908]) regulatory elements. Characterization of these Blbf-Sc1 transgenic mice show elevated Sc1 transcript and protein in an astroglial selective pattern throughout the CNS. This model provides a novel in vivo system for evaluating the role of SC1 in brain development and function, in general, and for understanding SC1's significance in the fate and function of astroglial cells, in particular. © 2008 Wiley-Liss, Inc. [source] Sp1-dependent regulation of the tissue inhibitor of metalloproteinases-1 promoterJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2004Minhyung Lee Abstract Extracellular matrix (ECM) remodeling is involved in many cellular properties such as division, migration, differentiation, and death. The turnover of ECM is regulated by matrix metalloproteinases (MMPs) and the MMPs are inhibited by the tissue inhibitors of metalloproteinases (TIMPs). In this study, the transcriptional regulation of the TIMP-1 promoter was investigated. The 5,-deletion assay showed that the region between ,1,200 and ,1,101 was responsible for the TIMP-1 promoter activity. The mutations of the two Sp1 sites in this region reduced the transcription activity. In addition, the co-transfection with antisense Sp1 oligonucleotide decreased the promoter activity, suggesting that the transcription of the TIMP-1 promoter is mediated by Sp1. Previously, it was reported that the TIMP-1 expression was enhanced under hypoxia. Therefore, the TIMP-1 promoter activity was investigated with or without cobalt ion, which elicits the same physiological effect as hypoxia. The results showed that the TIMP-1 promoter was induced in the presence of cobalt ion and that the promoter activity was regulated by Sp1 as well as HIF-1. Therefore, this study suggests that Sp1 is involved in the regulation of the TIMP-1 promoter in the presence of cobalt ion as well as in the basal level transcription. © 2004 Wiley-Liss, Inc. [source] Extracellular matrix regulates alpha s1-casein gene expression in rabbit primary mammary cells and CCAAT enhancer binding protein (C/EBP) binding activityJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2001Genevičve Jolivet Abstract Previous studies have shown that both the signal transducer and activator of transcription 5 (STAT5) and the CCAAT enhancer binding proteins (C/EBPs) are involved in the regulation of casein gene expression by mammary epithelial cells. Prolactin (Prl) activation of STAT5 is necessary for casein gene expression. The extracellular matrix (ECM) regulates also casein gene expression. Here, we have investigated whether ECM regulates C/EBPs activity in primary rabbit mammary epithelial cells. Isolated primary mammary cells were cultured on plastic or on floating collagen I gel. Prolactin induced ,s 1-casein gene expression when cells were cultured on collagen but not on plastic. It is noteworthy that activated STAT5 was detected in both culture conditions. Several STAT5 isoforms (STAT5a, STAT5b, and other STAT5 related isoforms, some with lower molecular weight than the full-length STAT5a and STAT5b) were detected under the different culture conditions. However, their presence was not related to the expression of ,s 1-casein gene. The binding of nuclear factors to a C/EBP specific binding site and the protein level of C/EBP, differed in cells cultured on plastic or on collagen but these parameters were not modified by Prl. This suggests that C/EBP binding activity was regulated by ECM and not by Prl. Interestingly, these modifications were correlated to the expression of the ,s 1-casein gene. Hence, the activation of the ,s 1-casein gene expression depends on two independent signals, one delivered by Prl via the activation of STAT5, the other delivered by ECM via C/EBP. J. Cell. Biochem. 82:371,386, 2001. © 2001 Wiley-Liss, Inc. [source] Extracellular matrix,polymer hybrid materials produced in a pulsed-flow bioreactor systemJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 3 2009Cecilia Aulin Abstract Cell adhesion, interaction with material, cell proliferation and the production of an extracellular matrix (ECM) are all important factors determining the successful performance of an engineered scaffold. Scaffold design should aim at creating structures which can guide cells into forming new, functional tissue. In this study, the concept of in situ deposition of ECM by human dermal fibroblasts onto a compliant, knitted poly (ethyleneterephtalate) support is demonstrated, creating in vitro produced ECM polymer hybrid materials for tissue engineering. Comparison of cells cultured under static and dynamic conditions were examined, and the structure and morphology of the materials so formed were evaluated, along with the amount collagen deposited by the seeded cells. In vitro produced ECM polymer hybrid scaffolds could be created in this way, with the dynamic culture conditions increasing ECM deposition. Histological analysis indicated a homogenous distribution of cells in the 1 mm thick scaffold, surrounded by a matrix-like structure. ECM deposition was observed throughout the materials wigh 81.6 µg/cm2 of collagen deposited after 6 weeks. Cell produced bundles of ECM fibres bridged the polymer filaments and anchored cells to the support. These findings open hereto unknown possibilities of producing materials with structure designed by engineering together with biochemical composition given by cells. Copyright © 2009 John Wiley & Sons, Ltd. [source] Extracellular matrix alters the relationship between tritiated thymidine incorporation and proliferation of MC3T3-E1 cells during osteogenesis in vitroCELL PROLIFERATION, Issue 1 2002W. J. Peterson Bone cells in vivo exist in direct contact with extracellular matrix, which regulates their basic biological processes including metabolism, development, growth and differentiation. Thus, the in vitro activity of cells cultured on tissue culture treated plastic could be different from the activity of cells cultured on their natural substrate. We selected MC3T3-E1 pre-osteoblastic cells to study the effect of extracellular matrix on cell proliferation because these cells undergo a progressive developmental sequence of proliferation and differentiation. MC3T3-E1 cells were cultured on plastic or plastic coated with ECM, fibronectin, collagen type I, BSA or poly l -lysine and their ability to proliferate was assessed by incorporation of [3H]dT or by enumeration of cells. Our results show that (1) ECM inhibits incorporation of [3H]dT by MC3T3-E1 cells; (2) collagen type I, but not BSA, poly l -lysine or fibronectin also inhibits incorporation of [3H]dT; (3) the level of ECM inhibition of [3H]dT incorporation is directly related to the number of cells cultured, but unrelated to the cell cycle distribution or endogenous thymidine content; (4) the kinetic profile of [3H]dT uptake suggest that ECM inhibits transport of [3H]dT from the extracellular medium, and (5) cell counts are similar in cultures whether cells are grown on plastic or ECM. These results suggest that decreased incorporation of [3H]dT by cells cultured on ECM is not reflective of bone cell proliferation. [source] Oestrogenic Steroids and Melanoma Cell Interaction with Adjacent Skin Cells Influence Invasion of Melanoma Cells In VitroPIGMENT CELL & MELANOMA RESEARCH, Issue 2000SHEILA MAC NEIL The invasion of melanoma is complex and multi-staged and involves changes in both cell/extracellular matrix (ECM) and cell/cell interactions. Female steroids and ,-MSH have also been reported to influence metastatic melanoma progression, but their mechanisms of action are unknown. Accordingly, our aim was to establish in vitro models to examine (a) the influence of sex steroids and ,-melanocyte-stimulating hormone (,-MSH) on tumour invasion and the influence of (b) ECM proteins and (c) adjacent cells on melanoma invasion. In the first model, melanoma cell invasion through fibronectin over 20 hr under serum-free conditions was used to investigate the effects of 17,-oestradiol and oestrone on the invasion of human melanoma cell lines, A375-SM and HBL. A375-SM, but not HBL cells, proved very susceptible to inhibition by female steroids. However, invasion of the HBL line was inhibited by ,-MSH. Using the second model of reconstructed human skin based on de-epidermised acellular dermis, we found that the HBL cells on their own failed to invade into the dermis (irrespective of the presence or absence of the basement membrane). However, there was a significant synergistic interaction between keratinocytes, fibroblasts and HBL cells, such that a modest invasion of HBLs into the dermis was seen within 2 weeks when other skin cells were present. In contrast, A375-SM cells showed a significant ability to invade the dermis in the absence of other cells, with less invasion when other skin cells were present. In summary, these models have provided new information on the extent to which melanoma cell invasion is sensitive to oestrogenic steroids and to ,-MSH and to interaction, not only with adjacent skin cells but also to the presence of basement membrane antigens. [source] Complete reconstruction of the retinal laminar structure from a cultured retinal pigment epithelium is triggered by altered tissue interaction and promoted by overlaid extracellular matricesDEVELOPMENTAL NEUROBIOLOGY, Issue 14 2009Fusako Kuriyama Abstract The retina regenerates from retinal pigment epithelial (RPE) cells by transdifferentiation in the adult newt and Xenopus laevis when it is surgically removed. This was studied under a novel culture condition, and we succeeded, for the first time, in developing a complete retinal laminar structure from a single epithelial sheet of RPE. We cultured a Xenopus RPE monolayer sheet isolated from the choroid on a filter cup with gels overlaid and found that the retinal tissue structure differentiated with all retinal layers present. In the culture, RPE cells isolated themselves from the culture substratum (filter membrane), migrated, and reattached to the overlaid gel, on which they initiated transdifferentiation. This was exactly the same as observed during in vivo retina regeneration of X. laevis. In contrast, when RPE monolayers were cultured similarly without isolation from the choroid, RPE cells proliferated, but remained pigmented instead of transdifferentiating, indicating that alteration in tissue interaction triggers transdifferentiation. We then examined under the conventional tissue culture condition whether altered RPE-choroid interaction induces Pax6 expression. Pax6 was upregulated in RPE cells soon after they were removed from the choroid, and this expression was not dependent of FGF2. FGF2 administration was needed for RPE cells to maintain Pax6 expression. From the present results, in addition to our previous ones, we propose a two-step mechanism of transdifferentiation: the first step is a reversible process and is initiated by the alteration of the cell-extracellular matrix and/or cell,cell interaction followed by Pax6 upregulation. FGF2 plays a key role in driving RPE cells into the second step, during which they differentiate into retinal stem cells. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009 [source] Expression of Pit2 sodium-phosphate cotransporter during murine odontogenesis is developmentally regulatedEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 6 2006Dawei Zhao Different sodium-dependent inorganic phosphate (Pi) uptake mechanisms play a major role in cellular Pi homeostasis. The function and detailed distribution patterns of the type III Na+ -phosphate cotransporter, PiT-2, in different organs during development are still largely unknown. We therefore examined the temporospatial expression patterns of Pit2 during murine odontogenesis. Odontoblasts were always devoid of Pit2 expression, whereas a transient, but strong, expression was detected in young secretory ameloblasts. However, the stratum intermedium and, later on, the papillary layer and cells of the subodontoblastic layer, exhibited high levels of Pit2 mRNA, which increased gradually as the tooth matured. Hormonal treatment or Pi starvation of tooth germs in vitro did not alter Pit2 levels or patterns of expression, indicating mechanisms of regulation different from those of PiT-1 or other cell types. PiT-2 also functions as a retroviral receptor, and functional membrane-localized protein was confirmed throughout the dental papilla/pulp by demonstrating cellular permissiveness to infection by a gammaretrovirus that uses PiT-2 as a receptor. The distinct pattern of Pit2 expression during odontogenesis suggests that its Pi -transporter function may be important for homeostasis of dental cells and not specifically for mineralization of the dental extracellular matrices. The expression of viral receptors in enamel-forming cells and the dental pulp may be of pathological significance. [source] Cellulose-binding modules from extracellular matrix proteins of Dictyostelium discoideum stalk and sheathFEBS JOURNAL, Issue 15 2001Yingzi Wang Cellulose-binding modules (CBMs) of two extracellular matrix proteins, St15 and ShD, from the slime mold Dictyostelium discoideum were expressed in Escherichia coli. The expressed proteins were purified to >,98% purity by extracting inclusion bodies at pH 11.5 and refolding proteins at pH 7.5. The two refolded CBMs bound tightly to amorphous phosphoric acid swollen cellulose (PASC), but had a low affinity toward xylan. Neither protein exhibited cellulase activity. St15, the stalk-specific protein, had fourfold higher binding affinity toward microcrystalline cellulose (Avicel) than the sheath-specific ShD CBM. St15 is unusual in that it consists of a solitary CBM homologous to family IIa CBMs. Sequence analysis of ShD reveals three putative domains containing: (a) a C-terminal CBM homologous to family IIb CBMs; (b) a Pro/Thr-rich linker domain; and (c) a N-terminal Cys-rich domain. The biological functions and potential role of St15 and ShD in building extracellular matrices during D. discoideum development are discussed. [source] Capturing Complex Protein Gradients on Biomimetic Hydrogels for Cell-Based AssaysADVANCED FUNCTIONAL MATERIALS, Issue 21 2009Steffen Cosson Abstract A versatile strategy to rapidly immobilize complex gradients of virtually any desired protein on soft poly(ethylene glycol) (PEG) hydrogel surfaces that are reminiscent of natural extracellular matrices (ECM) is reported. A microfluidic chip is used to generate steady-state gradients of biotinylated or Fc-tagged fusion proteins that are captured and bound to the surface in less than 5,min by NeutrAvidin or ProteinA, displayed on the surface. The selectivity and orthogonality of the binding schemes enables the formation of parallel and orthogonal overlapping gradients of multiple proteins, which is not possible on conventional cell culture substrates. After patterning, the hydrogels are released from the microfluidic chip and used for cell culture. This novel platform is validated by conducting single-cell migration experiments using time-lapse microscopy. The orientation of cell migration, as well as the migration rate of primary human fibroblasts, depends on the concentration of an immobilized fibronectin fragment. This technique can be readily applied to other proteins to address a wealth of biological questions with different cell types. [source] Tissue Engineering: Scaffold-Mediated 2D Cellular Orientations for Construction of Three Dimensionally Engineered Tissues Composed of Oriented Cells and Extracellular Matrices (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 7 2009Mater. Novel technology for fabrication of 3D-engineered tissues consisting of oriented cells and extracellular matrices (ECM) is described by Yoshida and co-workers on page 1001. They prepare disulfide-crosslinked hydrogels with oriented pores to induce cellular orientations on and in the scaffolds. Finally, 3D-oriented engineered tissues with 2D-cell and ECM orientation are successfully obtained by decomposing template gel with reductant agent. [source] Scaffold-Mediated 2D Cellular Orientations for Construction of Three Dimensionally Engineered Tissues Composed of Oriented Cells and Extracellular MatricesADVANCED FUNCTIONAL MATERIALS, Issue 7 2009Hiroaki Yoshida Abstract Various hydrogels, such as poly(, -glutamic acid) (, -PGA), gelatin (GT), alginic acid (Alg), and agarose (Aga), with 3D interconnected and oriented fibrous pores (OP gels) are prepared for 3D polymeric cellular scaffolds by using silica fiber cloth (SC) as template. After the preparation of these hydrogels with the SC templates, the latter are subsequently removed by washing with hydrofluoric acid solution. Scanning electron microscopy (SEM) clearly shows OP structures in the hydrogels. These various types of OP gels are successfully prepared in this way, independently of the crosslinking mechanism, such as chemical (, -PGA or GT), coordinate-bonded (Alg), or hydrogen-bonded (Aga) crosslinks. SEM, confocal laser scanning microscopy, and histological evaluations clearly demonstrate that mouse L929 fibroblast cells adhere to and extend along these OP structures on/in , -PGA hydrogels during 3D cell culture. The L929 cells that adhere on/in the oriented hydrogel are viable and proliferative. Furthermore, 3D engineered tissues, composed of the oriented cells and extracellular matrices (ECM) produced by the cells, are constructed in vitro by subsequent decomposition of the hydrogel with cysteine after 14 days of cell culture. This novel technology to fabricate 3D-engineered tissues, consisting of oriented cells and ECM, will be useful for tissue engineering. [source] An Integrin and Rho GTPase-Dependent Pinocytic Vacuole Mechanism Controls Capillary Lumen Formation in Collagen and Fibrin MatricesMICROCIRCULATION, Issue 1 2003GEORGE E. DAVIS ABSTRACT A major question that remains unanswered concerning endothelial cell (EC) morphogenesis is how lumens are formed in three-dimensional extracellular matrices (ECMs). Studies from many laboratories have revealed a critical role for an ECM-integrin-cytoskeletal signaling axis during EC morphogenesis. We have discovered a mechanism involving intracellular vacuole formation and coalescence that is required for lumen formation in several in vitro models of morphogenesis. In addition, a series of studies have observed vacuoles in vivo during angiogenic events. These vacuoles form through an integrin-dependent pinocytic mechanism in either collagen or fibrin matrices. In addition, we have shown that the Cdc42 and Rac1 guanosine triphosphatases (GTPases), which control actin and microtubule cytoskeletal networks, are required for vacuole and lumen formation. These GTPases are also known to regulate integrin signaling and are activated after integrin-matrix interactions. Furthermore, the expression of green fluorescent protein-Rac1 or -Cdc42 chimeric proteins in ECs results in the targeting of these fusion proteins to intracellular vacuole membranes during lumen formation. Thus, a matrix-integrin-cytoskeletal signaling axis involving both the Cdc42 and Rac1 GTPases regulates the process of EC lumen formation in three-dimensional collagen or fibrin matrices. [source] Histochemical evidence of osteoclastic degradation of extracellular matrix in osteolytic metastasis originating from human lung small carcinoma (SBC-5) cellsMICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2006Minqi Li Abstract The aim of this study was to assess the dynamics of osteoclast migration and the degradation of unmineralized extracellular matrix in an osteolytic metastasis by examining a well-standardized lung cancer metastasis model of nude mice. SBC-5 human lung small carcinoma cells were injected into the left cardiac ventricle of 6-week-old BALB/c nu/nu mice under anesthesia. At 25,30 days after injection, the animals were sacrificed and their femora and/or tibiae were removed for histochemical analyses. Metastatic lesions were shown to occupy a considerable area extending from the metaphyses to the bone marrow region. Tartrate resistant acid phosphatase (TRAPase)-positive osteoclasts were found in association with an alkaline phosphatase (ALPase)-positive osteoblastic layer lining the bone surface, but could also be localized in the ALPase-negative stromal tissues that border the tumor nodules. These stromal tissues were markedly positive for osteopontin, and contained a significant number of TRAPase-positive osteoclasts expressing immunoreactivity for CD44. We thus speculated that, mediating its affinity for CD44, osteopontin may serve to facilitate osteoclastic migration after their formation associated with ALPase-positive osteoblasts. We next examined the localization of cathepsin K and matrix metallo-proteinase-9 (MMP-9) in osteoclasts. Osteoclasts adjacent to the bone surfaces were positive for both proteins, whereas those in the stromal tissues in the tumor nests showed only MMP-9 immunoreactivity. Immunoelectron microscopy disclosed the presence of MMP-9 in the Golgi apparatus and in vesicular structures at the baso-lateral cytoplasmic region of the osteoclasts found in the stromal tissue. MMP-9-positive vesicular structures also contained fragmented extracellular materials. Thus, osteoclasts appear to either select an optimized function, namely secreting proteolytic enzymes from ruffled borders during bone resorption, or recognize the surrounding extracellular matrix by mediating osteopontin/CD44 interaction, and internalize the extracellular matrices. Microsc. Res. Tech. 69:73,83, 2006. © 2006 Wiley-Liss, Inc. [source] Regulation of global gene expression in the bone marrow microenvironment by androgen: Androgen ablation increases insulin-like growth factor binding protein-5 expressionTHE PROSTATE, Issue 15 2007Chang Xu Abstract BACKGROUND Prostate cancer frequently metastasizes to bone. Androgen suppression treatment is initially highly effective, but eventually results in resistant cancer cells. This study evaluates the effects of androgen suppression on the bone and bone marrow (BM). In particular we questioned whether the androgen therapy could adversely facilitate prostate cancer progression through an increase growth factor secretion by the bone microenvironment. METHODS Global gene expression is analyzed on mPEDB DNA microarrays. Insulin-like growth factor binding protein-5 (IGFBP5) is detected by immunohistochemistry in mouse tissues and its regulation measured by qPCR and Western blotting in human BM stromal cells. Effects of extracellular matrix-associated IGFBP5 on human prostate epithelial cells are tested in an MTS cell-growth assay. RESULTS Castration increases expression of 159 genes (including 4 secreted cytokines) and suppresses expression of 84 genes. IGFBP5 is most consistently increased and the increase in expression is reversed by testosterone administration. IGFBP5 protein is detected in vivo in osteoblasts, BM stromal cells, and endothelial cells. Primary human stromal cell cultures secrete IGFBP5. In vitro, treatment of immortalized human marrow stromal cells with charcoal-stripped serum increases IGFBP5 mRNA expression, which is reversed by androgen supplementation. IGFBP5 is incorporated into the extracellular matrix. Further, IGFBP5 immobilized on extracellular matrices of stromal cells enhances the growth of immortalized prostate epithelial cells. CONCLUSIONS Androgen suppressive therapy increases IGFBP5 in the BM microenvironment and thereby may facilitate the progression of prostate cancer. Prostate 67: 1621,1629, 2007. © 2007 Wiley-Liss, Inc. [source] A cell leakproof PLGA-collagen hybrid scaffold for cartilage tissue engineeringBIOTECHNOLOGY PROGRESS, Issue 3 2010Naoki Kawazoe Abstract A cell leakproof porous poly(DL -lactic-co-glycolic acid) (PLGA)-collagen hybrid scaffold was prepared by wrapping the surfaces of a collagen sponge except the top surface for cell seeding with a bi-layered PLGA mesh. The PLGA-collagen hybrid scaffold had a structure consisting of a central collagen sponge formed inside a bi-layered PLGA mesh cup. The hybrid scaffold showed high mechanical strength. The cell seeding efficiency was 90.0% when human mesenchymal stem cells (MSCs) were seeded in the hybrid scaffold. The central collagen sponge provided enough space for cell loading and supported cell adhesion, while the bi-layered PLGA mesh cup protected against cell leakage and provided high mechanical strength for the collagen sponge to maintain its shape during cell culture. The MSCs in the hybrid scaffolds showed round cell morphology after 4 weeks culture in chondrogenic induction medium. Immunostaining demonstrated that type II collagen and cartilaginous proteoglycan were detected in the extracellular matrices. Gene expression analyses by real-time PCR showed that the genes encoding type II collagen, aggrecan, and SOX9 were upregulated. These results indicated that the MSCs differentiated and formed cartilage-like tissue when being cultured in the cell leakproof PLGA-collagen hybrid scaffold. The cell leakproof PLGA-collagen hybrid scaffolds should be useful for applications in cartilage tissue engineering. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] Roles of pericellular proteolysis by membrane type-1 matrix metalloproteinase in cancer invasion and angiogenesisCANCER SCIENCE, Issue 7 2003Motoharu Seiki Behavior of cancer cells is profoundly affected by their microenvironment, which is often controlled by pericellular proteolysis or the processing of protein components, including extracellular matrices, growth factors, cytokines, receptors, cell adhesion molecules, and so on. Matrix metalloproteinases (MMPs) are a family of zinc-dependent proteases responsible for the proteolytic events in the extracellular milieu. Among the multiple MMPs expressed in a wide range of tumors, membrane type-1 MMP (MT1-MMP), which is expressed especially in tumor cells with significant invasive properties, is thought to be particularly important for pericellular proteolysis. Recent studies have elucidated in part how MT1-MMP is regulated biologically for the promotion of invasion by tumors or for angiogenesis by endothelial cells. Understanding of the proteolysis by, and the regulation of MT1-MMP, which probably promotes cell invasion, could provide a therapeutic hint as to how to block or delay the progression of cancer. [source] Regulation of TGF-, signaling and its roles in progression of tumorsCANCER SCIENCE, Issue 3 2003Kohei Miyazono Transforming growth factor-, (TGF-,) is a potent growth inhibitor of most types of cells; therefore, perturbations of TGF-, signaling are believed to result in progression of various tumors. On the other hand, TGF-, has been shown to act as an oncogenic cyto-kine through induction of extracellular matrices, angiogenesis, and immune suppression. A wide variety of effects of TGF-p are mediated by physical interaction of signal transducer Smad proteins with various transcription factors. Among these, Runx3 plays a pivotal role in prevention of gastric cancer. TGF-, signaling is regulated by various mechanisms in the cytoplasm and nucleus. Inhibitory Smads (l-Smads) repress TGF-, signaling mainly by interacting with activated TGF-, receptors. Smad ubiquitin regulatory factors (Smurfs) play important roles in facilitating the inhibitory signals induced by l-Smads. In addition, the transcrip-tional co-repressors c-Ski and SnoN interact with Smads, and repress transcription induced by TGF-,. Abnormalities of these regulators of TGF-, signaling may thus participate in the progression of various tumors. (Cancer Sci 2003; 94: 230,234) [source] Overload-induced skeletal muscle extracellular matrix remodelling and myofibre growth in mice lacking IL-6ACTA PHYSIOLOGICA, Issue 4 2009J. P. White Abstract Aim:, Overloading healthy skeletal muscle produces myofibre hypertrophy and extracellular matrix remodelling, and these processes are thought to be interdependent for producing muscle growth. Inflammatory cytokine interleukin-6 (IL-6) gene expression is induced in overloaded skeletal muscle, and the loss of this IL-6 induction can attenuate the hypertrophic response to overload (OV). Although the OV induction of IL-6 in skeletal muscle may be an important regulator of inflammatory processes and satellite cell proliferation, less is known about its role in the regulation of extracellular matrix remodelling. The purpose of the current study was to examine if OV-induced extracellular matrix remodelling, muscle growth, and associated gene expression were altered in mice that lack IL-6, when compared with wild-type mice. Methods:, Male C57/BL6 (WT) and C57/BL6 × IL-6,/, (IL-6,/,) mice (10 weeks of age) were assigned to either a sham control or synergist ablation OV treatments for 3, 21 or 56 days. Result:, Plantaris muscle mass increased 59% in WT and 116% in IL-6,/, mice after 21 day OV. Myofibre CSA was also increased by 21 day OV in both WT and IL-6,/, mice. OV induced a twofold greater increase in the volume of non-contractile tissue in IL-6,/, muscle compared to WT. OV also induced a significantly greater accumulation of hydroxyproline and procollagen-1 mRNA in IL-6,/, muscle, when compared with WT muscle after 21 day OV. Transforming growth factor-, and insulin-like growth factor-1 mRNA expression were also induced to a greater extent in IL-6,/, muscle when compared with WT muscle after 21 day OV. There was no effect of IL-6 loss on the induction of myogenin, and cyclin D1 mRNA expression after 3 day OV. However, MyoD mRNA expression in 3 day OV IL-6,/, muscle was attenuated when compared with WT OV mice. Conclusion:, IL-6 appears to be necessary for the normal regulation of extracellular matrix remodelling during OV-induced growth. [source] | |||||||||||||||||||||||||||||||||||||