scholarly journals The Short Arm of the Laminin γ2 Chain Plays a Pivotal Role in the Incorporation of Laminin 5 into the Extracellular Matrix and in Cell Adhesion

2001 ◽  
Vol 153 (4) ◽  
pp. 835-850 ◽  
Author(s):  
Laurent Gagnoux-Palacios ◽  
Maryline Allegra ◽  
Flavia Spirito ◽  
Olivier Pommeret ◽  
Christine Romero ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Cell Attachment ◽  
Biologically Active ◽  
Globular Domain ◽  
Stimulated Scattering ◽  
Laminin 5 ◽  
And Migration ◽  
Immunohistochemical Studies ◽  
Adhesion Ligand

Laminin 5 is a basement membrane component that actively promotes adhesion and migration of epithelial cells. Laminin 5 undergoes extracellular proteolysis of the γ2 chain that removes the NH2-terminal short arm of the polypeptide and reduces the size of laminin 5 from 440 to 400 kD. The functional consequence of this event remains obscure, although lines of evidence indicate that cleavage of the γ2 chain potently stimulated scattering and migration of keratinocytes and cancer cells. To define the biological role of the γ2 chain short arm, we expressed mutated γ2 cDNAs into immortalized γ2-null keratinocytes. By immunofluorescence and immunohistochemical studies, cell detachment, and adhesion assays, we found that the γ2 short arm drives deposition of laminin 5 into the extracellular matrix (ECM) and sustains cell adhesion. Our results demonstrate that the unprocessed 440-kD form of laminin 5 is a biologically active adhesion ligand, and that the γ2 globular domain IV is involved in intermolecular interactions that mediate integration of laminin 5 in the ECM and cell attachment.

Binding of hexabrachion (tenascin) to the extracellular matrix and substratum and its effect on cell adhesion

1990 ◽  
Vol 95 (2) ◽  
pp. 263-277
Author(s):  
V.A. Lightner ◽  
H.P. Erickson
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Cell Attachment ◽  
Solid Phase ◽  
Fluid Phase ◽  
Matrix Proteins ◽  
And Migration ◽  
Cover Up ◽  
Plastic Substratum

Hexabrachion is a large glycoprotein of the extracellular matrix (ECM) that is prominent in embryogenesis, wound healing and tumorigenesis. Because of the role of extracellular matrix proteins in the regulation of cell differentiation and migration, the interaction of hexabrachion with cells as well as with other components of the ECM is of great interest. Early reports suggested that hexabrachion does not bind to fibronectin or gelatin but does bind to chondroitin sulfate proteoglycans. However, more recent reports have suggested that hexabrachion binds to fibronectin and inhibits cell adhesion as well as cell migration on fibronectin. We have found no evidence of strong hexabrachion-fibronectin binding on either a solid-phase ELISA assay or in a fluid-phase sedimentation assay in which the reactants were allowed to dissociate. However, hexabrachion sedimentation was accelerated in a gradient containing fibronectin throughout. This demonstrates an association between hexabrachions and fibronectin, but the complex is apparently weak and readily reversible. The solid-phase ELISA also shows no evidence of hexabrachion binding to gelatin, laminin or types I, III, IV or V collagen. Hexabrachion does not support strong cell attachment of the cell lines tested. Moreover, hexabrachion can inhibit cell attachment to fibronectin. We demonstrate here that this inhibition requires the hexabrachion to be able to bind to the plastic substratum. The results suggest that hexabrachion inhibition is via a steric inhibition. When the hexabrachion molecules bind to the plastic, they cover up a significant fraction of the underlying fibronectin molecules. Antibody studies are presented that show that hexabrachion can nonspecifically block access of immunoglobulin G molecules to the underlying matrix. This steric blocking is not unique to hexabrachion.

alpha 3A beta 1 integrin localizes to focal contacts in response to diverse extracellular matrix proteins

1995 ◽  
Vol 108 (6) ◽  
pp. 2321-2336 ◽  
Author(s):  
C.M. DiPersio ◽  
S. Shah ◽  
R.O. Hynes
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Broad Spectrum ◽  
Time Course ◽  
Cell Attachment ◽  
Cell Types ◽  
Cytoplasmic Domain ◽  
Laminin 5 ◽  
Focal Contacts

In vitro binding assays and inhibition of cell adhesion with monoclonal antibodies have implicated the integrin alpha 3 beta 1 as a receptor for a variety of extracellular ligands. However, reports of alpha 3 beta 1-ligand interactions are inconsistent, and transfection studies have suggested that alpha 3 beta 1 is not sufficient for cell attachment to ligands other than kalinin/laminin 5. We used immunofluorescence to study subcellular localization of the alpha 3A cytoplasmic domain variant in different cultured cell types. Using standard fixation and permeabilization methods, antibodies specific for alpha 3A stained most cell types in a diffuse pattern, consistent with previous reports. Surprisingly, however, chemical cross-linking of integrins to the extracellular matrix and extraction of the cytoskeleton prior to immunofluorescence revealed alpha 3A in focal contacts of most cells tested, suggesting that the cytoplasmic domain was concealed in intact focal contacts by cytoskeletal or other cytoplasmic proteins. The alpha 3A subunit localized to focal contacts in several cell types cultured on fibronectin, kalinin/laminin 5, EHS-laminin/laminin 1, type IV collagen, or vitronectin. In contrast, alpha 5 and alpha V integrins were detected in focal contacts only in cells grown on their known ligands (fibronectin, and fibronectin or vitronectin, respectively). Therefore, our results show that alpha 3A beta 1 responds to a broad spectrum of extracellular ligands. Time course comparisons of the recruitment of alpha subunits from different fibronectin receptors suggested that localization of alpha 3A beta 1 to fibronectin-induced focal contacts was independent of the recruitment of alpha 5 and alpha 4 integrins. However, other studies have shown that alpha 3A beta 1 does not mediate initial cell adhesion to many of the ligands that induced its focal contact localization, including fibronectin. Therefore, we suggest that alpha 3A beta 1 may be a secondary receptor with post-cell-adhesion functions for a broad spectrum of extracellular matrices.

scholarly journals Extracellular matrix derived peptides and mesenchymal stem cell motility

2021 ◽  
Author(s):  
◽  
Sandi Grainne Dempsey
Keyword(s):  
Extracellular Matrix ◽  
Wound Healing ◽  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Cell Motility ◽  
Cell Attachment ◽  
Mass Spectrometry Analysis ◽  
And Migration ◽  
Proliferation And Migration

<p>Biomaterials derived from decellularised extracellular matrices have shown promise as tools in tissue regeneration and wound healing. Such materials display biocompatibility as well as inherent bioactivity, promoting constructive remodelling in healing tissues. In this study, the bioactivity of ovine forestomach matrix (a decellularised extracellular matrix biomaterial) is assessed based on its ability to affect the proliferation and migration of wound healing cells.  This material supported cell attachment and proliferation, but did not allow cell infiltration in vitro. Enzymatic digestion of the material rendered soluble components that were able to induce proliferation and migration of some cell types. Cell-mediated processing of the material generated a protein or proteins with chemotactic activity for mesenchymal stem cells in vitro. Mass spectrometry analysis indicated the bioactive component consisted of the proteoglycan decorin, or fragments thereof. Decorin has not previously been shown to induce mesenchymal stem cell motility, and these findings may add to what is known about decorin and its role in constructive remodelling. Furthermore, this cell-mediated approach for ECM breakdown could lead to the discovery of other bioactive peptides involved in ECM remodelling and wound healing.</p>

scholarly journals Xenopus embryonic cell adhesion to fibronectin: position-specific activation of RGD/synergy site-dependent migratory behavior at gastrulation.

1996 ◽  
Vol 134 (1) ◽  
pp. 227-240 ◽  
Author(s):  
J W Ramos ◽  
D W DeSimone
Keyword(s):  
Cell Adhesion ◽  
Matrix Protein ◽  
Marginal Zone ◽  
Cell Attachment ◽  
Extracellular Matrix Protein ◽  
Mesoderm Induction ◽  
Type Iii ◽  
Basic Body ◽  
And Migration

During Xenopus laevis gastrulation, the basic body plan of the embryo is generated by movement of the marginal zone cells of the blastula into the blastocoel cavity. This morphogenetic process involves cell adhesion to the extracellular matrix protein fibronectin (FN). Regions of FN required for the attachment and migration of involuting marginal zone (IMZ) cells were analyzed in vitro using FN fusion protein substrates. IMZ cell attachment to FN is mediated by the Arg-Gly-Asp (RGD) sequence located in the type III-10 repeat and by the Pro-Pro-Arg-Arg-Ala-Arg (PPRRAR) sequence in the type III-13 repeat of the Hep II domain. IMZ cells spread and migrate persistently on fusion proteins containing both the RGD and synergy site sequence Pro-Pro-Ser-Arg-Asn (PPSRN) located in the type III-9 repeat. Cell recognition of the synergy site is positionally regulated in the early embryo. During gastrulation, IMZ cells will spread and migrate on FN whereas presumptive pre-involuting mesoderm, vegetal pole endoderm, and animal cap ectoderm will not. However, animal cap ectoderm cells acquire the ability to spread and migrate on the RGD/synergy region when treated with the mesoderm inducing factor activin-A. These data suggest that mesoderm induction activates the position-specific recognition of the synergy site of FN in vivo. Moreover, we demonstrate the functional importance of this site using a monoclonal antibody that blocks synergy region-dependent cell spreading and migration on FN. Normal IMZ movement is perturbed when this antibody is injected into the blastocoel cavity indicating that IMZ cell interaction with the synergy region is required for normal gastrulation.

biomimetic Hydrogel/apatite Nanocomposite Scaffolds for Bone Regeneration

2005 ◽  
Vol 897 ◽  
Author(s):  
Esmaiel Jabbari
Keyword(s):  
Ethylene Oxide ◽  
Bone Regeneration ◽  
Cell Attachment ◽  
Degradation Kinetics ◽  
Bone Matrix ◽  
Biologically Active ◽  
Structural Support ◽  
Cellular Environment ◽  
Gel Phase ◽  
And Migration

AbstractBone is a composite material consisting of aqueous gel and mineral phases. The aqueous gel phase gives bone its form and contributes to its ability to resist tension, while the mineral component resists compression. The combination of a hard inorganic phase and an elastic gel network provides bone with unique mechanical properties as well as a medium for diffusion and release of biologically active agents and it also facilitates communication with the cellular environment. A tissue engineered synthetic biomaterial as a scaffold for bone regeneration should provide temporary structural support to the reconstructed region and a medium for solubilization, diffusion, release of nutrients and growth factors, and their interactions with cells. In this work, the material and biologic properties of a novel synthetic matrix metalloproteinase (MMP) degradable hydrogel/apatite nanocomposite is investigated for its usefulness as a model matrix to mimic the gel and mineral components of the bone matrix and to fabricate aqueous-based scaffolds for bone regeneration. The gel phase is made from poly(lactide-ethylene oxide-fumarate), hereafter designated as PLEOF, terpolymer in which the water content can be adjusted by changing the ratio of the hydrophobic (lactide) to hydrophilic (ethylene oxide) oligomers. The hydrogel and apatite phases are crosslinked using an MMP degradable peptide crosslinker to modulate the matrix degradation kinetics with the migration of bone marrow stromal (BMS) cells. The results demonstrate that MMP degradable scaffolds fabricated from the PLEOF hydrogel and apatite nanoparticles are biocompatible and support cell attachment and migration.

scholarly journals The LG3 Module of Laminin-5 Harbors a Binding Site for Integrin α3β1That Promotes Cell Adhesion, Spreading, and Migration

2001 ◽  
Vol 276 (35) ◽  
pp. 33045-33053 ◽  
Author(s):  
Meiling Shang ◽  
Naohiko Koshikawa ◽  
Susann Schenk ◽  
Vito Quaranta
Keyword(s):  
Cell Adhesion ◽  
Binding Site ◽  
Laminin 5 ◽  
And Migration

scholarly journals Extracellular matrix derived peptides and mesenchymal stem cell motility

2021 ◽  
Author(s):  
◽  
Sandi Grainne Dempsey
Keyword(s):  
Extracellular Matrix ◽  
Wound Healing ◽  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Cell Motility ◽  
Cell Attachment ◽  
Mass Spectrometry Analysis ◽  
And Migration ◽  
Proliferation And Migration

<p>Biomaterials derived from decellularised extracellular matrices have shown promise as tools in tissue regeneration and wound healing. Such materials display biocompatibility as well as inherent bioactivity, promoting constructive remodelling in healing tissues. In this study, the bioactivity of ovine forestomach matrix (a decellularised extracellular matrix biomaterial) is assessed based on its ability to affect the proliferation and migration of wound healing cells.  This material supported cell attachment and proliferation, but did not allow cell infiltration in vitro. Enzymatic digestion of the material rendered soluble components that were able to induce proliferation and migration of some cell types. Cell-mediated processing of the material generated a protein or proteins with chemotactic activity for mesenchymal stem cells in vitro. Mass spectrometry analysis indicated the bioactive component consisted of the proteoglycan decorin, or fragments thereof. Decorin has not previously been shown to induce mesenchymal stem cell motility, and these findings may add to what is known about decorin and its role in constructive remodelling. Furthermore, this cell-mediated approach for ECM breakdown could lead to the discovery of other bioactive peptides involved in ECM remodelling and wound healing.</p>

scholarly journals Recreation of the terminal events in physiological integrin activation

2010 ◽  
Vol 188 (1) ◽  
pp. 157-173 ◽  
Author(s):  
Feng Ye ◽  
Guiqing Hu ◽  
Dianne Taylor ◽  
Boris Ratnikov ◽  
Andrey A. Bobkov ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Integrin Signaling ◽  
Integrin Activation ◽  
Matrix Assembly ◽  
Integrin Αiibβ3 ◽  
Terminal Events ◽  
Cell Adhesion And Migration ◽  
And Migration

Increased affinity of integrins for the extracellular matrix (activation) regulates cell adhesion and migration, extracellular matrix assembly, and mechanotransduction. Major uncertainties concern the sufficiency of talin for activation, whether conformational change without clustering leads to activation, and whether mechanical force is required for molecular extension. Here, we reconstructed physiological integrin activation in vitro and used cellular, biochemical, biophysical, and ultrastructural analyses to show that talin binding is sufficient to activate integrin αIIbβ3. Furthermore, we synthesized nanodiscs, each bearing a single lipid-embedded integrin, and used them to show that talin activates unclustered integrins leading to molecular extension in the absence of force or other membrane proteins. Thus, we provide the first proof that talin binding is sufficient to activate and extend membrane-embedded integrin αIIbβ3, thereby resolving numerous controversies and enabling molecular analysis of reconstructed integrin signaling.

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