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Fibrin binds to collagen and provides a bridge for αVβ3 integrin-dependent contraction of collagen gels.

Reyhani V, Seddigh P, Guss B, Gustafsson R, Rask L, Rubin K - Biochem. J. (2014)

Bottom Line: This allowed murine myoblast C2C12 cells to contract the collagenous composite gel via αVβ3 integrin.A specific competitive inhibitor blocking the Col-I-binding site for fibrinogen abolished the organization of fibrin into discernable fibrils, as well as the C2C12-mediated contraction of Col I gels.Our data show that fibrin can function as a linkage protein between Col I fibres and cells, and suggest that fibrin at inflammatory sites indirectly connects αVβ3 integrins to Col I fibres and thereby promotes cell-mediated contraction of collagenous tissue structures.

View Article: PubMed Central - PubMed

Affiliation: *Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, BMC Box 582, SE-751 23 Uppsala, Sweden.

ABSTRACT
The functional significance of fibrin deposits typically seen in inflammatory lesions, carcinomas and in healing wounds is not fully understood. In the present study, we demonstrate that fibrinogen/fibrin specifically bound to native Col I (collagen type I) and used the Col I fibre network as a base to provide a functional interface matrix that connects cells to the Col I fibres through αVβ3 integrins. This allowed murine myoblast C2C12 cells to contract the collagenous composite gel via αVβ3 integrin. We show that fibrinogen specifically bound to immobilized native Col I at the site known to bind matrix metalloproteinase-1, discoidin domain receptor-2 and fibronectin, and that binding had no effect on Col I fibrillation. A specific competitive inhibitor blocking the Col-I-binding site for fibrinogen abolished the organization of fibrin into discernable fibrils, as well as the C2C12-mediated contraction of Col I gels. Our data show that fibrin can function as a linkage protein between Col I fibres and cells, and suggest that fibrin at inflammatory sites indirectly connects αVβ3 integrins to Col I fibres and thereby promotes cell-mediated contraction of collagenous tissue structures.

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Fibrin binds to the matrix-binding site of Col I fibres and this binding stabilizes the secondary network of fibrin(A and B) Representative SEM images of fibrin (50 μg/ml)/Col I (1 mg/ml) gels. Thin fibres of fibrin were interwoven with the thicker Col I fibres forming a secondary network. (C and D) CNE, a streptococcal protein that inhibits the binding of fibrinogen to Col I, at a concentration of ~350 nM abolished the association of thin fibrin fibrils with the Col I fibre network. (E and F) Representative micrographs of pure Col I gels. (G and H) CNE (350 nM) had no overt effect on the fibre network structure of pure Col I gels. (I and J) Representative micrographs of fibrin/Col I composite gels consisting of a high concentration of fibrin (1 mg/ml) in Col I (1 mg/ml).
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Figure 6: Fibrin binds to the matrix-binding site of Col I fibres and this binding stabilizes the secondary network of fibrin(A and B) Representative SEM images of fibrin (50 μg/ml)/Col I (1 mg/ml) gels. Thin fibres of fibrin were interwoven with the thicker Col I fibres forming a secondary network. (C and D) CNE, a streptococcal protein that inhibits the binding of fibrinogen to Col I, at a concentration of ~350 nM abolished the association of thin fibrin fibrils with the Col I fibre network. (E and F) Representative micrographs of pure Col I gels. (G and H) CNE (350 nM) had no overt effect on the fibre network structure of pure Col I gels. (I and J) Representative micrographs of fibrin/Col I composite gels consisting of a high concentration of fibrin (1 mg/ml) in Col I (1 mg/ml).

Mentions: The fibrin-triggered C2C12-mediated contraction of Col I gels was investigated further by addition of different concentrations of fibrinogen to Col I gels. The addition of fibrinogen at 50 and 100 μg/ml allowed for an effective C2C12-mediated Col I gel contraction, whereas higher concentrations, such as 500 and 1000 μg/ml, repressed gel contraction, presumably due to a prohibitively high stiffness (Figure 1D). Interestingly, fibril structure analysis of the composite gels consisting of a high concentration of fibrin (1000 μg/ml) showed a more dense fibril network with almost no empty spaces within the meshwork of fibrin fibres and Col I fibrils (see Figures 6I and 6J).


Fibrin binds to collagen and provides a bridge for αVβ3 integrin-dependent contraction of collagen gels.

Reyhani V, Seddigh P, Guss B, Gustafsson R, Rask L, Rubin K - Biochem. J. (2014)

Fibrin binds to the matrix-binding site of Col I fibres and this binding stabilizes the secondary network of fibrin(A and B) Representative SEM images of fibrin (50 μg/ml)/Col I (1 mg/ml) gels. Thin fibres of fibrin were interwoven with the thicker Col I fibres forming a secondary network. (C and D) CNE, a streptococcal protein that inhibits the binding of fibrinogen to Col I, at a concentration of ~350 nM abolished the association of thin fibrin fibrils with the Col I fibre network. (E and F) Representative micrographs of pure Col I gels. (G and H) CNE (350 nM) had no overt effect on the fibre network structure of pure Col I gels. (I and J) Representative micrographs of fibrin/Col I composite gels consisting of a high concentration of fibrin (1 mg/ml) in Col I (1 mg/ml).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109839&req=5

Figure 6: Fibrin binds to the matrix-binding site of Col I fibres and this binding stabilizes the secondary network of fibrin(A and B) Representative SEM images of fibrin (50 μg/ml)/Col I (1 mg/ml) gels. Thin fibres of fibrin were interwoven with the thicker Col I fibres forming a secondary network. (C and D) CNE, a streptococcal protein that inhibits the binding of fibrinogen to Col I, at a concentration of ~350 nM abolished the association of thin fibrin fibrils with the Col I fibre network. (E and F) Representative micrographs of pure Col I gels. (G and H) CNE (350 nM) had no overt effect on the fibre network structure of pure Col I gels. (I and J) Representative micrographs of fibrin/Col I composite gels consisting of a high concentration of fibrin (1 mg/ml) in Col I (1 mg/ml).
Mentions: The fibrin-triggered C2C12-mediated contraction of Col I gels was investigated further by addition of different concentrations of fibrinogen to Col I gels. The addition of fibrinogen at 50 and 100 μg/ml allowed for an effective C2C12-mediated Col I gel contraction, whereas higher concentrations, such as 500 and 1000 μg/ml, repressed gel contraction, presumably due to a prohibitively high stiffness (Figure 1D). Interestingly, fibril structure analysis of the composite gels consisting of a high concentration of fibrin (1000 μg/ml) showed a more dense fibril network with almost no empty spaces within the meshwork of fibrin fibres and Col I fibrils (see Figures 6I and 6J).

Bottom Line: This allowed murine myoblast C2C12 cells to contract the collagenous composite gel via αVβ3 integrin.A specific competitive inhibitor blocking the Col-I-binding site for fibrinogen abolished the organization of fibrin into discernable fibrils, as well as the C2C12-mediated contraction of Col I gels.Our data show that fibrin can function as a linkage protein between Col I fibres and cells, and suggest that fibrin at inflammatory sites indirectly connects αVβ3 integrins to Col I fibres and thereby promotes cell-mediated contraction of collagenous tissue structures.

View Article: PubMed Central - PubMed

Affiliation: *Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, BMC Box 582, SE-751 23 Uppsala, Sweden.

ABSTRACT
The functional significance of fibrin deposits typically seen in inflammatory lesions, carcinomas and in healing wounds is not fully understood. In the present study, we demonstrate that fibrinogen/fibrin specifically bound to native Col I (collagen type I) and used the Col I fibre network as a base to provide a functional interface matrix that connects cells to the Col I fibres through αVβ3 integrins. This allowed murine myoblast C2C12 cells to contract the collagenous composite gel via αVβ3 integrin. We show that fibrinogen specifically bound to immobilized native Col I at the site known to bind matrix metalloproteinase-1, discoidin domain receptor-2 and fibronectin, and that binding had no effect on Col I fibrillation. A specific competitive inhibitor blocking the Col-I-binding site for fibrinogen abolished the organization of fibrin into discernable fibrils, as well as the C2C12-mediated contraction of Col I gels. Our data show that fibrin can function as a linkage protein between Col I fibres and cells, and suggest that fibrin at inflammatory sites indirectly connects αVβ3 integrins to Col I fibres and thereby promotes cell-mediated contraction of collagenous tissue structures.

Show MeSH
Related in: MedlinePlus