scholarly journals The role of intermolecular disulfide bonding in deposition of GP140 in the extracellular matrix.

1984 ◽  
Vol 99 (1) ◽  
pp. 105-114 ◽  
Author(s):  
W G Carter
Keyword(s):  
Extracellular Matrix ◽  
Culture Media ◽  
Molecular Forms ◽  
Cell Protein ◽  
Cell Contact ◽  
Relative Molecular Mass ◽  
Disulfide Bonding ◽  
Sequence Of Events ◽  
The Matrix ◽  
Matrix Precipitation

Human WI-38 fibroblasts in cultures synthesized at least three molecular forms of the major, extracellular matrix glycoprotein (GP), GP140: (a) cytoplasmic GP140 (1.2 ng of GP140/micrograms of cell protein) was detergent-soluble, underglycosylated, and possessed detectable levels of intermolecular disulfide bonding; (b) matrix GP140 (3.6 ng of GP140/micrograms of cell protein) was detergent-insoluble, more highly glycosylated and polymerized by intermolecular disulfide bonding, and co-distributed in the extracellular matrix with fibronectin; and (c) released GP140 (2 ng of GP140/micrograms of cell protein per 24 h) was recovered in the conditioned culture media and lacked intermolecular disulfide bonding. Cytoplasmic GP140 was the immediate biosynthetic precursor of the matrix form of GP140. In addition, various human adult and fetal tissues contained a form of GP140 that resembled the fibroblast matrix GP140 in the degree of intermolecular disulfide bonding, relative molecular mass, and immunological reactivity. Analysis of the sequence of events in assembly of GP140 and fibronectin in the extracellular matrix detected the following: (a) fibronectin was first to appear in the extracellular matrix; (b) GP140 accumulated in the cytoplasm, then deposited in the extracellular matrix and co-aligned with the established fibronectin; and (c) maturation of the extracellular matrix proceeded by continued intermolecular disulfide bonding. To evaluate possible roles for intermolecular disulfide bonding in cell interactions, a unique assay system was utilized based on the ability of labeled cells to incorporate radioactive matrix components into a biotinylated exogenous matrix. Precipitation of the biotinylated matrix from extracts of the cultures using avidin indicated: (a) disulfide bonding of radioactive GP140 and fibronectin into the exogenous biotinylated matrix required cell contact with the matrix. The newly deposited GP140 and fibronectin derived from the cells and not from GP140 and fibronectin present in the conditioned culture media. (b) Pro-alpha 1 and Pro-alpha 2 procollagens, present in the culture media, bound to the exogenous matrix in a noncovalent manner and were independent of cell contact. (c) SV40 transformed cells (WI-38 VA13) synthesized released form GP140 but did not deposit GP140 into the biotinylated matrix.

scholarly journals Regulated secretion of a serine protease that activates an extracellular matrix-degrading metalloprotease during fertilization in Chlamydomonas.

1989 ◽  
Vol 109 (4) ◽  
pp. 1689-1694 ◽  
Author(s):  
W J Snell ◽  
W A Eskue ◽  
M J Buchanan
Keyword(s):  
Extracellular Matrix ◽  
Cell Wall ◽  
Serine Protease ◽  
Cellular Responses ◽  
Cell Contact ◽  
Relative Molecular Mass ◽  
Mating Types ◽  
Dibutyryl Camp ◽  
Sexual Signal ◽  
Regulated Secretion

During fertilization in the biflagellated alga, Chlamydomonas reinhardtii, gametes of opposite mating types adhere to each other via agglutinin molecules located on their flagellar surfaces, generating a sexual signal that induces several cellular responses including cell wall release. This cell contact-generated signal is mediated by cAMP and release of the wall, which is devoid of cellulose and contains several hydroxyproline-rich glycoproteins, is due to the activation of a metalloprotease, lysin. Although we originally assumed that lysin would be stored intracellularly in a compartment structurally separate from its substrate, recently we showed that lysin is stored in the periplasm as an inactive, higher relative molecular mass precursor, prolysin (Buchanan, M.J., S. H. Imam, W. A. Eskue, and W. J. Snell. 1989. J. Cell Biol. 108:199-207). Here we show that conversion of prolysin to lysin is due to a cellular, nonperiplasmic enzyme that has the properties of a serine protease. Release of this serine protease into the periplasm is induced by incubation of gametes in dibutyryl cAMP. This may be one of the few examples of regulated secretion of a protease in a eucaryotic microorganism and a novel example of regulated secretion in a plant system.

Abstract 359: The Production of Acellular Cardiac Extracellular Matrix from P3 Murine Heart

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Stefan M Kren ◽  
Daniel J Garry ◽  
Mary G Garry
Keyword(s):  
Extracellular Matrix ◽  
Cardiac Tissue ◽  
Fluorescent Protein ◽  
Cultured Cells ◽  
Culture Media ◽  
Heart Tissue ◽  
Cell Nuclei ◽  
Dapi Staining ◽  
Neonatal Heart ◽  
The Matrix

Introduction: Understanding the role of extracellular matrix (ECM) in the creation of the cellular microenvironment during tissue formation and regeneration could be vital in extending this capability to injured adult tissue. To date the only confirmed mammalian heart tissue regeneration/regrowth has been in neonatal murine heart, with the regenerative capacity ceasing after day P3. By focusing on ECM from P3 heart tissue we hope to elucidate its contribution to regenerative plasticity and transfer this capacity to injured adult myocardium. Hypothesis: Detergent decellularization protocols used in adult tissues can be modified to function on a neonatal scale, serving to remove the cellular components of the neonatal heart, leaving structurally intact ECM to serve as a scaffold for the generation of cardiac tissue equivalents. Materials and Methods: Murine P3 hearts were perfused with 1% SDS in water at 20mm Hg for 12 hrs. Following detergent decellularization, perfusion with water, 1% Triton X-100, PBS and culture media restored biocompatibility to the isolated ECM. P1 and P7 primary cardiomyocytes expressing the mCherry red fluorescent protein reporter under control of the alpha myosin promoter were isolated by enzymatic disassociation and cultured in the heart matrix in a perfusion based bioreactor. Results: The decellularized ECM demonstrated removal of 97% of native DNA when compared to control by pico-green dsDNA binding assay. Histologic analysis demonstrated an absence of cell nuclei by H & E and DAPI staining. The preservation of the matrix structure and the maintenance of matrix immunoreactivity (collagen IV) were also demonstrated histologically. Following infusion of P1 or P7 mCherry positive cells, contractile behavior of the recellularized heart constructs was observed, and markers of cardiac linage (alpha-actinin in mCherry positive cells) were present. Conclusions: Neonatal heart matrix can be effectively decellularized. With appropriate modification of perfusion parameters, pediatric ECM structure can be preserved. This isolated matrix can serve as a scaffold for growth and maintenance of immature and mature cardiomyocytes, supporting continued contractility of cultured cells.

scholarly journals Molecular assembly, secretion, and matrix deposition of type VI collagen.

1986 ◽  
Vol 102 (3) ◽  
pp. 703-710 ◽  
Author(s):  
E Engvall ◽  
H Hessle ◽  
G Klier
Keyword(s):  
Extracellular Matrix ◽  
Culture Media ◽  
Molecular Assembly ◽  
Collagen Molecule ◽  
Type Vi Collagen ◽  
Cultured Fibroblasts ◽  
Intracellular Pool ◽  
Matrix Deposition ◽  
The Matrix ◽  
Tissue Form

Monoclonal antibodies reactive with the tissue form of type VI collagen were used to isolate the type VI collagen polypeptides from cultured fibroblasts and muscle cells. Two [35S]methionine-labeled polypeptides of 260 and 140 kD were found intracellularly, in the medium, and in the extracellular matrix of metabolically labeled cells. These polypeptides were disulfide cross-linked into very large complexes. The 260- and 140-kD polypeptides were intimately associated and could not be separated from each other by reduction without denaturation. In the absence of ascorbic acid, both polypeptides accumulated inside the cell, and their amounts in the medium and in the matrix were decreased. These results suggest that both the 260- and the 140-kD polypeptides are integral parts of the type VI collagen molecule. Examination of type VI collagen isolated from the intracellular pool by electron microscopy after rotary shadowing revealed structures corresponding to different stages of assembly of type VI collagen. Based on these images, a sequence for the intracellular assembly of type VI collagen could be discerned. Type VI collagen monomers are approximately 125 nm long and are composed of two globules separated by a thin strand. The monomers assemble into dimers and tetramers by lateral association. Only tetramers were present in culture media, whereas both tetramers and multimers were found in extracellular matrix extracts. The multimers appeared to have assembled from tetramers by end-to-end association into filaments that had prominent knobs and a periodicity of approximately 110 nm. These results show that, unlike other collagens, type VI collagen is assembled into tetramers before it is secreted from the cells, and they also suggest an extracellular aggregation mechanism that appears to be unique to this collagen.

Development of a three-dimensional extracellular matrix synthesized by human diploid fibroblasts in vitro

1986 ◽  
Vol 84 (1) ◽  
pp. 183-200
Author(s):  
E.E. Qwarnstrom ◽  
R.C. Page
Keyword(s):  
Extracellular Matrix ◽  
Light And Electron Microscopy ◽  
Root Surface ◽  
Human Tooth ◽  
Immunocytochemical Staining ◽  
Cell Contact ◽  
Collagen Fibres ◽  
Intense Staining ◽  
Fibrillar Material ◽  
The Matrix

Development and maturation of an extracellular matrix, synthesized by human gingival fibroblasts, have been studied microscopically. Pairs of demineralized, fibronectin-coated slices of human tooth root, 300 micron thick, were placed on confluent cell layers, defining a 0.5 mm wide space. The cultures were grown under standard conditions with ascorbic acid (50 micrograms ml-1) added daily. At various times up to 13 weeks, the cultures were fixed and the samples prepared for light and electron microscopy. Cells from the monolayer became attached to, and migrated up, the vertical root surface and, during the time studied, completely filled the space between the root slices with an extracellular matrix. A close association was seen between the cell membrane and collagen fibres in the demineralized surface initially. A thin layer of fibrillar material was deposited between the cell and the vertical surface, and eventually an extracellular matrix surrounding the cells and attaching to the root surface was present. Samples fixed in the presence of Ruthenium Red showed intense staining of the fibrillar material, indicating the presence of anionic molecules. Additional cells migrated onto the newly synthesized matrix and up the root surface. Growth of the fibrillar networks on either side, horizontally and vertically, continued and, eventually, an extracellular matrix attaching to the vertical surfaces completely filled the previously empty space. Immunocytochemical staining showed that the matrix contained hyaluronic acid, chondroitin sulphate, dermatan sulphate and fibronectin at this time. Collagen fibres were observed at 6 weeks, and at later times collagen types I, III and V were the primary matrix components. The fibroblasts attaching to the root slice and those present at the edge of the matrix had an elongated, polar form. The cells within the matrix frequently showed a stellate appearance with numerous extended processes, in contact with fibrillar material or collagen fibres. Fibroblast processes were at later times seen to enclose bundles of collagen fibres and to mediate cell-to-cell contact, occasionally via desmosome-like structures. The structure and composition of the matrix and the appearance and apparent behaviour of the cells were similar to that observed in the healing wound. This system thus could provide a model for studying various aspects of regeneration of extracellular matrix.

High-resolution observations of metastable γ’ precipitation in Al-15at.%Ag

1996 ◽  
Vol 54 ◽  
pp. 1004-1005
Author(s):  
N. V. Larcher ◽  
I. G. Solorzano
Keyword(s):  
Discontinuous Precipitation ◽  
Equilibrium Phase ◽  
Quantitative Description ◽  
Present Contribution ◽  
Α Phase ◽  
The Matrix ◽  
Aging Sequence ◽  
Matrix Precipitation ◽  
Considerable Detail ◽  
Kinetics Of

It is currently well established that, for an Al-Ag alloy quenched from the α phase and aged within the metastable solvus, the aging sequence is: supersaturated α → GP zones → γ’ → γ (Ag2Al). While GP zones and plate-shaped γ’ are metastable phases, continuously distributed in the matrix, formation of the equilibrium phase γ takes place at grain boundaries by discontinuous precipitation (DP). The crystal structure of both γ’ and γ is hep with the following orientation relationship with respect to the fee α matrix: {0001}γ′,γ // {111}α, <1120>γ′,γ, // <110>α.The mechanisms and kinetics of continuous matrix precipitation (CMP) in dilute Al-Ag alloys have been studied in considerable detail. The quantitative description of DP kinetics, however, has received less attention. The present contribution reports the microstructural evolution resulting from aging an Al-Ag alloy with Ag content higher than those previously reported in the literature, focusing the observations of γ' plate-shaped metastable precipitates.

Extracellular matrix: the gatekeeper of tumor angiogenesis

2019 ◽  
Vol 47 (5) ◽  
pp. 1543-1555 ◽  
Author(s):  
Maurizio Mongiat ◽  
Simone Buraschi ◽  
Eva Andreuzzi ◽  
Thomas Neill ◽  
Renato V. Iozzo
Keyword(s):  
Extracellular Matrix ◽  
Tumor Angiogenesis ◽  
Signaling Cascades ◽  
Cancer Growth ◽  
Cell Behavior ◽  
Metastatic Progression ◽  
Surface Receptors ◽  
The Matrix ◽  
Multiple Signaling

Abstract The extracellular matrix is a network of secreted macromolecules that provides a harmonious meshwork for the growth and homeostatic development of organisms. It conveys multiple signaling cascades affecting specific surface receptors that impact cell behavior. During cancer growth, this bioactive meshwork is remodeled and enriched in newly formed blood vessels, which provide nutrients and oxygen to the growing tumor cells. Remodeling of the tumor microenvironment leads to the formation of bioactive fragments that may have a distinct function from their parent molecules, and the balance among these factors directly influence cell viability and metastatic progression. Indeed, the matrix acts as a gatekeeper by regulating the access of cancer cells to nutrients. Here, we will critically evaluate the role of selected matrix constituents in regulating tumor angiogenesis and provide up-to-date information concerning their primary mechanisms of action.

Effect of dexamethasone on the expression of MMPs, adenosine A1 receptors and NFKB by human trabecular meshwork cells

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Normie Aida Mohd Nasir ◽  
Renu Agarwal ◽  
Anna Krasilnikova ◽  
Siti Hamimah Sheikh Abdul Kadir ◽  
Igor Iezhitsa
Keyword(s):  
Extracellular Matrix ◽  
Western Blot ◽  
Trabecular Meshwork ◽  
Culture Media ◽  
Smooth Muscle Actin ◽  
Adenosine A1 Receptors ◽  
Trabecular Meshwork Cells ◽  
Aqueous Humor Dynamics ◽  
Nfkb Activation ◽  
Adenosine A1

AbstractObjectivesSteroid-induced ocular hypertension and glaucoma are associated with extracellular matrix remodeling at the trabecular meshwork (TM) of the eye due to reduced secretion of matrix metalloproteinases (MMPs), a family of enzymes regulating extracellular matrix proteolysis. Several biological functions of steroids are known to involve regulation of adenosine A1 receptors (A1AR) and nuclear factor kappa B (NFKB). Since MMPs expression in TM has been shown to be regulated by A1AR as well as transcription factors, it is likely that dexamethasone-induced changes in aqueous humor dynamics involve reduced MMP and A1AR expression and reduced NFKB activation. Hence, the current study investigated the association of dexamethasone-induced reduction in MMP secretion with reduced NFKB activation and A1AR expression.MethodsHuman trabecular meshwork cells (HTMCs) were characterized by estimating myocilin and alpha smooth muscle actin expression and then were treated with dexamethasone 100 nM for 2, 5 and 7 days. The MMP secretion was estimated in culture media using Western blot. Immunocytochemistry (ICC) and ELISA were done to investigate the effect of dexamethasone on NFKB phosphorylation. A1AR expression in HTMCs was determined using Western blot and ELISA.ResultsDexamethasone caused a significant reduction in both MMP-2 and -9 expression compared to untreated group after five and seven days but not after two days of culture. Significantly reduced phosphorylated NFKB and A1AR protein levels were detected in dexamethasone treated compared to vehicle treated HTMCs after five days of culture.ConclusionsDexamethasone reduces MMP-2 and -9 secretion by HTMCs and this effect of dexamethasone is associated with reduced NFKB phosphorylation and A1AR expression.

Cell-to-cell contact and extracellular matrix

1994 ◽  
Vol 6 (5) ◽  
pp. 645-647 ◽  
Author(s):  
Alan F. Horwitz ◽  
Jean Paul Thiery
Keyword(s):  
Extracellular Matrix ◽  
Cell Contact

scholarly journals von Willebrand factor released from Weibel-Palade bodies binds more avidly to extracellular matrix than that secreted constitutively

Blood ◽  
1987 ◽  
Vol 69 (5) ◽  
pp. 1531-1534 ◽  
Author(s):  
LA Sporn ◽  
VJ Marder ◽  
DD Wagner
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Von Willebrand Factor ◽  
Immunofluorescent Staining ◽  
Cultured Endothelial Cells ◽  
Human Foreskin Fibroblasts ◽  
Platelet Binding ◽  
The Matrix ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Large multimers of von Willebrand factor (vWf) are released from the Weibel-Palade bodies of cultured endothelial cells following treatment with a secretagogue (Sporn et al, Cell 46:185, 1986). These multimers were shown by immunofluorescent staining to bind more extensively to the extracellular matrix of human foreskin fibroblasts than constitutively secreted vWf, which is composed predominantly of dimeric molecules. Increased binding of A23187-released vWf was not due to another component present in the releasate, since releasate from which vWf was adsorbed, when added together with constitutively secreted vWf, did not promote binding. When iodinated plasma vWf was overlaid onto the fibroblasts, the large forms bound preferentially to the matrix. These results indicated that the enhanced binding of the vWf released from the Weibel-Palade bodies was likely due to its large multimeric size. It appears that multivalency is an important component of vWf interaction with the extracellular matrix, just as has been shown for vWf interaction with platelets. The pool of vWf contained within the Weibel-Palade bodies, therefore, is not only especially suited for platelet binding, but also for interaction with the extracellular matrix.

Cell-to-cell contact and extracellular matrix

1999 ◽  
Vol 11 (5) ◽  
pp. 535-536
Author(s):  
Jonathon Pines ◽  
Luca Toldo ◽  
Frank Lafont
Keyword(s):  
Extracellular Matrix ◽  
Cell Contact
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