scholarly journals Integrin α2β1 Is a Receptor for the Cartilage Matrix Protein Chondroadherin

1997 ◽  
Vol 138 (5) ◽  
pp. 1159-1167 ◽  
Author(s):  
Lisbet Camper ◽  
Dick Heinegård ◽  
Evy Lundgren-Åkerlund
Keyword(s):  
Cell Adhesion ◽  
Matrix Protein ◽  
Collagen Type ◽  
Human Fibroblasts ◽  
Cartilage Matrix ◽  
Affinity Column ◽  
Integrin Subunit ◽  
Β1 Integrin ◽  
Type Ii ◽  
Collagen Type Ii

Chondroadherin (the 36-kD protein) is a leucine-rich, cartilage matrix protein known to mediate adhesion of isolated chondrocytes. In the present study we investigated cell surface proteins involved in the interaction of cells with chondroadherin in cell adhesion and by affinity purification. Adhesion of bovine articular chondrocytes to chondroadherin-coated dishes was dependent on Mg2+ or Mn2+ but not Ca2+. Adhesion was partially inhibited by an antibody recognizing β1 integrin subunit. Chondroadherin-binding proteins from chondrocyte lysates were affinity purified on chondroadherin-Sepharose. The β1 integrin antibody immunoprecipitated two proteins with molecular mass ∼110 and 140 kD (nonreduced) from the EDTA-eluted material. These results indicate that a β1 integrin on chondrocytes interacts with chondroadherin. To identify the α integrin subunit(s) involved in interaction of cells with the protein, we affinity purified chondroadherin-binding membrane proteins from human fibroblasts. Immunoprecipitation of the EDTA-eluted material from the affinity column identified α2β1 as a chondroadherin-binding integrin. These results are in agreement with cell adhesion experiments where antibodies against the integrin subunit α2 partially inhibited adhesion of human fibroblast and human chondrocytes to chondroadherin. Since α2β1 also is a receptor for collagen type II, we tested the ability of different antibodies against the α2 subunit to inhibit adhesion of T47D cells to collagen type II and chondroadherin. The results suggested that adhesion to collagen type II and chondroadherin involves similar or nearby sites on the α2β1 integrin. Although α2β1 is a receptor for both collagen type II and chondroadherin, only adhesion of cells to collagen type II was found to mediate spreading.

Immunohistochemical Localization of Matrix Proteins in the Femoral Joint Cartilage of Growing Commercial Pigs

1992 ◽  
Vol 29 (6) ◽  
pp. 514-520 ◽  
Author(s):  
S. Ekman ◽  
D. Heinegård
Keyword(s):  
Subchondral Bone ◽  
Matrix Protein ◽  
Collagen Type ◽  
Immunohistochemical Localization ◽  
Matrix Composition ◽  
Type Ii ◽  
Collagen Type Ii ◽  
Chondrocyte Maturation ◽  
Proliferative Zone ◽  
The Matrix

The immunocytochemical localization of several matrix macromolecules, including collagen type II and proteoglycans, in the distal femoral articular-epiphyseal cartilage complex of 15 commercial pigs between the age of 6 and 18 weeks was studied. Early osteochondrotic lesions, i.e., chondronecrosis in the resting region of the growth cartilage, as well as extensions of necrotic cartilage into the subchondral bone, were present in all animals, except those 6 weeks old. A battery of antibodies were used for identification of macromolecules in the matrix at different stages of the disease. Chondrocyte involvement in the process could be studied by identifying the sequence of alterations in matrix macromolecules as the lesion developed. The immunostaining for aggrecan (large aggregating proteoglycans), cartilage oligomeric matrix protein, fibronectin, collagen type II, fibromodulin, and biglycan was more prominent in the areas of chondronecrosis, extending into the subchondral bone, than in the normal resting region. This altered pattern of matrix macromolecules resembled that of the matrix of the proliferative chondrocytes and suggests that the chondrocyte maturation had stopped in the proliferative zone. The matrix in the areas of chondronecrosis in the resting region resembled that in the normal resting region. Thus the chondronecrosis appears to have preceded alterations of the matrix composition. The antibody reactivity pattern was, however, altered in the matrix of the clustered chondrocytes in areas of chondronecrosis. Staining in these regions suggested a more prominent appearance of fibronectin and collagen type II than in the normal matrix of the resting region. These changes are suggestive of attempt to repair. The chondronecrotic areas restricted to the resting region have a matrix that is different from the matrix of the abnormal cartilage extending into the subchondral bone, which resembled the matrix of the proliferative region. Hence the osteochondrotic lesion may not start in the resting region, instead the maturation of chondrocytes seems to stop in the proliferative zone, which would result in impaired bone formation.

scholarly journals Signal transduction by β1 integrin receptors in human chondrocytes in vitro: collaboration with the insulin-like growth factor-I receptor

1999 ◽  
Vol 342 (3) ◽  
pp. 615-623 ◽  
Author(s):  
Mehdi SHAKIBAEI ◽  
Thilo JOHN ◽  
Philippe DE SOUZA ◽  
Rahim RAHMANZADEH ◽  
Hans-Joachim MERKER
Keyword(s):  
Growth Factor ◽  
Focal Adhesion ◽  
Collagen Type ◽  
Β1 Integrin ◽  
Insulin Like Growth Factor ◽  
Type Ii ◽  
Collagen Type Ii ◽  
Collagen Binding ◽  
Factor I ◽  
Igf I

We have examined the mechanism by which collagen-binding integrins co-operate with insulin-like growth factor-I (IGF-I) receptors (IGF-IR) to regulate chondrocyte phenotype and differentiation. Adhesion of chondrocytes to anti-β1 integrin antibodies or collagen type II leads to phosphorylation of cytoskeletal and signalling proteins localized at focal adhesions, including α-actinin, vinculin, paxillin and focal adhesion kinase (FAK). These stimulate docking proteins such as Shc (Src-homology collagen). Moreover, exposure of collagen type II-cultured chondrocytes to IGF-I leads to co-immunoprecipitation of Shc protein with the IGF-IR and with β1, α1 and α5 integrins, but not with α3 integrin. Shc then associates with growth factor receptor-bound protein 2 (Grb2), an adaptor protein and extracellular signal-regulated kinase. The expression of the docking protein Shc occurs only when chondrocytes are bound to collagen type II or integrin antibodies and increases when IGF-I is added, suggesting a collaboration between integrins and growth factors in a common/shared biochemical signalling pathway. Furthermore, these results indicate that focal adhesion assembly may facilitate signalling via Shc, a potential common target for signal integration between integrin and growth-factor signalling regulatory pathways. Thus, the collagen-binding integrins and IGF-IR co-operate to regulate focal adhesion components and these signalling pathways have common targets (Shc-Grb2 complex) in subcellular compartments, thereby linking to the Ras-mitogen-activated protein kinase signalling pathway. These events may play a role during chondrocyte differentiation.

Cartilage-Specific Matrix and Integrin Expression in Three-Dimensional Articular Chondrocyte Cultures Overexpressing Human Interleukin-10

2008 ◽  
Vol 1 ◽  
pp. CMAMD.S560
Author(s):  
Riccarda D. Müller ◽  
Thilo John ◽  
Benjamin Kohl ◽  
Anja Feldner ◽  
Hala Zreiqat ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Collagen Type ◽  
Articular Chondrocytes ◽  
Three Dimensional ◽  
3D Culture ◽  
Type I ◽  
Β1 Integrin ◽  
Type Ii ◽  
Collagen Type Ii ◽  
Chondrocyte Cultures

Interleukin (IL)-10 overexpression inhibits joint inflammation, however the effect of high local concentrations of IL-10 on chondrocyte homeostasis remains unclear. The aim of this study was to determine the effects of IL-10 overexpression on cartilage matrix production in three-dimensional (3D) chondrocyte cultures. Human articular chondrocytes were transduced with adenoviral vectors alone (adv/empty) or by vectors either overexpressing enhanced green fluorescence protein (adv/EGFP) or human IL-10 (adv/hIL-10) before their transfer to a 3D culture system. Non-transduced chondrocytes were used as controls. The expression of IL-10 or EGFP was confirmed using ELISA or flow cytometry. Chondrocytes synthesis of collagen types II and I, aggrecan, fibronectin and β1-integrin was determined over a period of 14 days post transduction using flow cytometry or immunohistochemistry. adv/EGFP or adv/IL-10 transduced chondrocytes expressed EGFP or secreted IL-10 detectable over the 2 weeks culture period. No suppression of collagen type II, aggrecan or β1-integrin synthesis by IL-10 overexpression was found and the deposition of collagen type I and fibronectin remained unaffected compared to the controls. IL-10 overexpression does not impair key features of chondrocytes differentiated phenotype (e.g. collagen type II and aggrecan expression) suggesting the potential use of IL-10 for gene therapeutic approaches in the joint.

Specificity and T cell receptor β chain usage of a human collagen type II-reactive T cell clone derived from a healthy individual

1992 ◽  
Vol 22 (1) ◽  
pp. 51-56 ◽  
Author(s):  
Tan Yan ◽  
Harald Burkhardt ◽  
Thomas Ritter ◽  
Barbara Bröker ◽  
Karl Heinz Mann ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Collagen Type ◽  
Cell Clone ◽  
Cell Receptor ◽  
Type Ii ◽  
Collagen Type Ii ◽  
T Cell Clone ◽  
Human Collagen ◽  
Β Chain

Localization of pro-collagen type ii mrna and collagen type ii in the healing tooth socket of the rat

1995 ◽  
Vol 40 (3) ◽  
pp. 181-185 ◽  
Author(s):  
H. Devlin ◽  
J. Hoyland ◽  
A.J. Freemont ◽  
P. Sloan
Keyword(s):  
Collagen Type ◽  
Type Ii ◽  
Collagen Type Ii ◽  
Tooth Socket

scholarly journals Stimulation of beta1 integrins on fibroblasts induces PDGF independent tyrosine phosphorylation of PDGF beta-receptors.

1996 ◽  
Vol 132 (4) ◽  
pp. 741-752 ◽  
Author(s):  
C Sundberg ◽  
K Rubin
Keyword(s):  
Cell Adhesion ◽  
Tyrosine Phosphorylation ◽  
Collagen Type ◽  
Collagen Gel ◽  
Collagen Type I ◽  
Receptor Activation ◽  
Type I ◽  
Integrin Subunit ◽  
Beta Receptor ◽  
Beta Receptors

We report that integrin-mediated signaling induces a rapid and transient tyrosine phosphorylation of platelet-derived growth factor (PDGF) beta-receptors in human diploid foreskin AG 1518 fibroblasts. A transient tyrosine phosphorylation of PDGF beta-receptors was evident one and two hours after cells had been plated on collagen type I and fibronectin, as well as on immobilized anti-integrin subunit IgG, but not on poly-L-lysine. In contrast EGF or PDGF alpha-receptors were not phosphorylated on tyrosine residues under these conditions. Tyrosine phosphorylation of PDGF beta-receptors induced by plating on collagen type I was inhibited by cytochalasin D and herbimycin A, unaffected by cycloheximide and enhanced by orthovanadate. Furthermore, a transient phosphorylation of PDGF beta-receptors occurred when AG 518 fibroblasts were cultured in three-dimensional collagen lattices or exposed to external strain exerted through centrifugation. The latter effect was evident already after two minutes. Clustering of cell surface beta1 integrins led to PDGF beta-receptor phosphorylation both in suspended and firmly attached AG 1518 fibroblasts. Plating of cells on collagen type I, fibronectin, and anti-beta1-integrin IgG resulted in the formation of PDGF beta-receptor aggregates as detected by immunofluorescence. Suramin or anti-PDGF-BB IgG had no effect on the plating-induced tyrosine phosphorylation of PDGF beta-receptors. PDGF-B chain mRNA, or protein, were not detected in AG 1518 fibroblasts. Our data suggest that a ligand-independent PDGF beta-receptor activation during cell adhesion and early phases of cell spreading is involved in integrin-mediated signaling in fibroblasts, and constitutes parts of a mechanism for cells to respond during the dynamic phases of externally applied tension as well as fibroblast-mediated tension during cell adhesion and collagen gel contraction.

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