[24] Extracellular matrix assembly

The assembly of an organism requires the interaction between different layers of cells, in many cases via an extracellular matrix. In the developing Drosophila larva, muscles attach in an integrin-dependent manner to the epidermis, via a specialized extracellular matrix called tendon matrix. Tiggrin, a tendon matrix integrin ligand, is primarily synthesized by cells distant to the muscle attachment sites, yet it accumulates specifically at these sites. Previous work has shown that the PS integrins are not required for tiggrin localization, suggesting that there is redundancy among tiggrin receptors. We have examined this by testing whether the PS2 integrin can recruit tiggrin to ectopic locations within the Drosophila embryo. We found that neither the wild type nor modified forms of the PS2 integrin, which have higher affinity for tiggrin, can recruit tiggrin to new cellular contexts. Next, we genetically manipulated the fate of the muscles and the epidermal muscle attachment cells, which demonstrated that muscles have the primary role in recruiting tiggrin to the tendon matrix and that cell-cell contact is necessary for this recruitment. Thus we propose that the inherent polarity of the muscle cells leads to a molecular specialization of their ends, and interactions between the ends produces an integrin-independent tiggrin receptor. Thus, interaction between cells generates an extracellular environment capable of nucleating extracellular matrix assembly.

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Control of extracellular matrix assembly by syndecan-2 proteoglycan

Journal of Cell Science ◽

10.1242/jcs.113.3.493 ◽

2000 ◽

Vol 113 (3) ◽

pp. 493-506 ◽

Cited By ~ 10

Author(s):

C.M. Klass ◽

J.R. Couchman ◽

A. Woods

Keyword(s):

Extracellular Matrix ◽

Chinese Hamster ◽

Surface Expression ◽

Metabolic Labeling ◽

Sulfate Proteoglycan ◽

S2 Cells ◽

Matrix Assembly ◽

The Matrix ◽

Beta1 Integrin ◽

Assembly Defect

Extracellular matrix (ECM) deposition and organization is maintained by transmembrane signaling and integrins play major roles. We now show that a second transmembrane component, syndecan-2 heparan sulfate proteoglycan, is pivotal in matrix assembly. Chinese Hamster Ovary (CHO) cells were stably transfected with full length (S2) or truncated syndecan-2 lacking the C-terminal 14 amino acids of the cytoplasmic domain (S2deltaS). No differences in the amount of matrix assembly were noted with S2 cells, but those expressing S2deltaS could not assemble laminin or fibronectin into a fibrillar matrix. The loss of matrix formation was not caused by a failure to synthesize or externalize ECM components as determined by metabolic labeling or due to differences in surface expression of alpha5 or beta1 integrin. The matrix assembly defect was at the cell surface, since S2deltaS cells also lost the ability to rearrange laminin or fibronectin substrates into fibrils and to bind exogenous fibronectin. Transfection of activated alphaIIbalphaLdeltabeta3 integrin into alpha(5)-deficient CHO B2 cells resulted in reestablishment of the previously lost fibronectin matrix. However, cotransfection of this cell line with S2deltaS could override the presence of activated integrins. These results suggest a regulatory role for syndecan-2 in matrix assembly, along with previously suggested roles for activated integrins.

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Establishment of substratum polarity in the blastocoel roof of the Xenopus embryo

Development ◽

10.1242/dev.126.9.1975 ◽

1999 ◽

Vol 126 (9) ◽

pp. 1975-1984 ◽

Cited By ~ 3

Author(s):

M. Nagel ◽

R. Winklbauer

Keyword(s):

Extracellular Matrix ◽

Cell Migration ◽

Signaling Pathways ◽

Fibril Formation ◽

Fgf Signaling ◽

Matrix Assembly ◽

Mesoderm Cell ◽

Guidance Cues ◽

Mesoderm Formation ◽

Fibronectin Fibrils

The fibronectin fibril matrix on the blastocoel roof of the Xenopus gastrula contains guidance cues that determine the direction of mesoderm cell migration. The underlying guidance-related polarity of the blastocoel roof is established in the late blastula under the influence of an instructive signal from the vegetal half of the embryo, in particular from the mesoderm. Formation of an oriented substratum depends on functional activin and FGF signaling pathways in the blastocoel roof. Besides being involved in tissue polarization, activin and FGF also affect fibronectin matrix assembly. Activin treatment of the blastocoel roof inhibits fibril formation, whereas FGF modulates the structure of the fibril network. The presence of intact fibronectin fibrils is permissive for directional mesoderm migration on the blastocoel roof extracellular matrix.

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Fibulin's Organization into the Extracellular Matrix of Fetal Lung Fibroblasts Is Dependent on Fibronectin Matrix Assembly

American Journal of Respiratory Cell and Molecular Biology ◽

10.1165/ajrcmb/8.5.538 ◽

1993 ◽

Vol 8 (5) ◽

pp. 538-545 ◽

Cited By ~ 26

Author(s):

Jesse Roman ◽

John A. McDonald

Keyword(s):

Extracellular Matrix ◽

Fetal Lung ◽

Lung Fibroblasts ◽

Matrix Assembly ◽

Fibronectin Matrix

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Challenges in Fabrication of Tissue-Engineered Cartilage with Correct Cellular Colonization and Extracellular Matrix Assembly

International Journal of Molecular Sciences ◽

10.3390/ijms19092700 ◽

2018 ◽

Vol 19 (9) ◽

pp. 2700 ◽

Cited By ~ 10

Author(s):

Mikko Lammi ◽

Juha Piltti ◽

Juha Prittinen ◽

Chengjuan Qu

Keyword(s):

Extracellular Matrix ◽

Articular Cartilage ◽

Pore Size ◽

Cartilage Tissue ◽

Cellular Interactions ◽

Matrix Assembly ◽

Small Pore ◽

Culture Models ◽

Open Question ◽

Engineered Cartilage

A correct articular cartilage ultrastructure regarding its structural components and cellularity is important for appropriate performance of tissue-engineered articular cartilage. Various scaffold-based, as well as scaffold-free, culture models have been under development to manufacture functional cartilage tissue. Even decellularized tissues have been considered as a potential choice for cellular seeding and tissue fabrication. Pore size, interconnectivity, and functionalization of the scaffold architecture can be varied. Increased mechanical function requires a dense scaffold, which also easily restricts cellular access within the scaffold at seeding. High pore size enhances nutrient transport, while small pore size improves cellular interactions and scaffold resorption. In scaffold-free cultures, the cells assemble the tissue completely by themselves; in optimized cultures, they should be able to fabricate native-like tissue. Decellularized cartilage has a native ultrastructure, although it is a challenge to obtain proper cellular colonization during cell seeding. Bioprinting can, in principle, provide the tissue with correct cellularity and extracellular matrix content, although it is still an open question as to how the correct molecular interaction and structure of extracellular matrix could be achieved. These are challenges facing the ongoing efforts to manufacture optimal articular cartilage.

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BMP-1 disrupts cell adhesion and enhances TGF-β activation through cleavage of the matricellular protein thrombospondin-1

Science Signaling ◽

10.1126/scisignal.aba3880 ◽

2020 ◽

Vol 13 (639) ◽

pp. eaba3880 ◽

Cited By ~ 3

Author(s):

Cyril Anastasi ◽

Patricia Rousselle ◽

Maya Talantikite ◽

Agnès Tessier ◽

Caroline Cluzel ◽

...

Keyword(s):

Extracellular Matrix ◽

Cell Adhesion ◽

Growth Factor ◽

Transforming Growth Factor ◽

Transforming Growth Factor Β ◽

Substantial Effect ◽

Matricellular Protein ◽

Matrix Assembly ◽

Morphogenetic Protein ◽

Thrombospondin 1

Bone morphogenetic protein 1 (BMP-1) is an important metalloproteinase that synchronizes growth factor activation with extracellular matrix assembly during morphogenesis and tissue repair. The mechanisms by which BMP-1 exerts these effects are highly context dependent. Because BMP-1 overexpression induces marked phenotypic changes in two human cell lines (HT1080 and 293-EBNA cells), we investigated how BMP-1 simultaneously affects cell-matrix interactions and growth factor activity in these cells. Increasing BMP-1 led to a loss of cell adhesion that depended on the matricellular glycoprotein thrombospondin-1 (TSP-1). BMP-1 cleaved TSP-1 between the VWFC/procollagen-like domain and the type 1 repeats that mediate several key TSP-1 functions. This cleavage induced the release of TSP-1 C-terminal domains from the extracellular matrix and abolished its previously described multisite cooperative interactions with heparan sulfate proteoglycans and CD36 on HT1080 cells. In addition, BMP-1–dependent proteolysis potentiated the TSP-1–mediated activation of latent transforming growth factor–β (TGF-β), leading to increased signaling through the canonical SMAD pathway. In primary human corneal stromal cells (keratocytes), endogenous BMP-1 cleaved TSP-1, and the addition of exogenous BMP-1 enhanced cleavage, but this had no substantial effect on cell adhesion. Instead, processed TSP-1 promoted the differentiation of keratocytes into myofibroblasts and stimulated production of the myofibroblast marker α-SMA, consistent with the presence of processed TSP-1 in human corneal scars. Our results indicate that BMP-1 can both trigger the disruption of cell adhesion and stimulate TGF-β signaling in TSP-1–rich microenvironments, which has important potential consequences for wound healing and tumor progression.

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Glycosaminoglycan–Protein Interactions: The First Draft of the Glycosaminoglycan Interactome

Journal of Histochemistry & Cytochemistry ◽

10.1369/0022155420946403 ◽

2020 ◽

pp. 002215542094640 ◽

Cited By ~ 2

Author(s):

Sylvain D. Vallet ◽

Olivier Clerc ◽

Sylvie Ricard-Blum

Keyword(s):

Extracellular Matrix ◽

Protein Interactions ◽

Dermatan Sulfate ◽

Protein Complexes ◽

Keratan Sulfate ◽

Protein Interaction Networks ◽

Interaction Networks ◽

Matrix Proteins ◽

Matrix Assembly ◽

Gag Protein

The six mammalian glycosaminoglycans (GAGs), chondroitin sulfate, dermatan sulfate, heparin, heparan sulfate, hyaluronan, and keratan sulfate, are linear polysaccharides. Except for hyaluronan, they are sulfated to various extent, and covalently attached to proteins to form proteoglycans. GAGs interact with growth factors, morphogens, chemokines, extracellular matrix proteins and their bioactive fragments, receptors, lipoproteins, and pathogens. These interactions mediate their functions, from embryonic development to extracellular matrix assembly and regulation of cell signaling in various physiological and pathological contexts such as angiogenesis, cancer, neurodegenerative diseases, and infections. We give an overview of GAG–protein interactions (i.e., specificity and chemical features of GAG- and protein-binding sequences), and review the available GAG–protein interaction networks. We also provide the first comprehensive draft of the GAG interactome composed of 832 biomolecules (827 proteins and five GAGs) and 932 protein–GAG interactions. This network is a scaffold, which in the future should integrate structures of GAG–protein complexes, quantitative data of the abundance of GAGs in tissues to build tissue-specific interactomes, and GAG interactions with metal ions such as calcium, which plays a major role in the assembly of the extracellular matrix and its interactions with cells. This contextualized interactome will be useful to identify druggable GAG–protein interactions for therapeutic purpose:

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