Activation of mannan-binding lectin-associated serine proteases leads to generation of a fibrin clot
Activation of mannan-binding lectin-associated serine proteases leads to generation of a fibrin clot
The lectin pathway of complement is activated upon binding of mannan-binding lectin (MBL) or ficolins (FCNs) to their targets. Upon recognition of targets, the MBL-and FCN-associated serine proteases (MASPs) are activated, allowing them to generate the C3 convertase C4b2a. Recent findings indicate that the MASPs also activate components of the coagulation system. We have previously shown that MASP-1 has thrombin-like activity whereby it cleaves and activates fibrinogen and factor XIII. MASP-2 has factor Xa-like activity and activates prothrombin through cleavage to form thrombin. We now report that purified L-FCN-MASPs complexes, bound from serum to N-acetylcysteine-Sepharose, or MBL-MASPs complexes, bound to mannan-agarose, generate clots when incubated with calcified plasma or purified fibrinogen and factor XIII. Plasmin digestion of the clot and analysis using anti-D-dimer antibodies revealed that the clot was made up of fibrin and was similar to that generated by thrombin in normal human plasma. Fibrinopeptides A and B (FPA and FPB, respectively) were released after fibrinogen cleavage by L-FCN-MASPs complexes captured on N-acetylcysteine-Sepharose. Studies of inhibition of fibrinopeptide release indicated that the dominant pathway for clotting catalysed by the MASPs is via MASP-2 and prothrombin activation, as hirudin, a thrombin inhibitor that does not inhibit MASP-1 and MASP-2, substantially inhibits fibrinopeptide release. In the light of their potent chemoattractant effects on neutrophil and fibroblast recruitment, the MASP-mediated release of FPA and FPB may play a role in early immune activation. Additionally, MASP-catalysed deposition and polymerization of fibrin on the surface of micro-organisms may be protective by limiting the dissemination of infection.
coagulation, lectin pathway, mannan-binding lectin, mannan-binding lectin-associated serine proteases
482-495
Gulla, Krishana C.
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Gupta, Kshitij
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Krarup, Anders
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Gal, Peter
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Schwaeble, Wilhelm J.
353e3aac-98af-4f5d-8acb-5d55e189c50f
Sim, Robert B.
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O’Connor, C. David
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Hajela, Krishnan
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2 December 2010
Gulla, Krishana C.
3568dfd0-4fd8-4e3b-bede-2c6af22941f4
Gupta, Kshitij
836c4228-574a-4887-b1d0-eda4213f931b
Krarup, Anders
7711f30f-7d23-4f9c-bb9e-c55f145be451
Gal, Peter
3abcb19a-4d29-455d-a64a-8810c57de422
Schwaeble, Wilhelm J.
353e3aac-98af-4f5d-8acb-5d55e189c50f
Sim, Robert B.
af835975-64a2-4d62-9d43-cf3ea77a622a
O’Connor, C. David
508d32e6-2d31-4c72-91ed-5d7c6404a9be
Hajela, Krishnan
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Gulla, Krishana C., Gupta, Kshitij, Krarup, Anders, Gal, Peter, Schwaeble, Wilhelm J., Sim, Robert B., O’Connor, C. David and Hajela, Krishnan
(2010)
Activation of mannan-binding lectin-associated serine proteases leads to generation of a fibrin clot.
Immunology, 129 (4), .
(doi:10.1111/j.1365-2567.2009.03200.x).
Abstract
The lectin pathway of complement is activated upon binding of mannan-binding lectin (MBL) or ficolins (FCNs) to their targets. Upon recognition of targets, the MBL-and FCN-associated serine proteases (MASPs) are activated, allowing them to generate the C3 convertase C4b2a. Recent findings indicate that the MASPs also activate components of the coagulation system. We have previously shown that MASP-1 has thrombin-like activity whereby it cleaves and activates fibrinogen and factor XIII. MASP-2 has factor Xa-like activity and activates prothrombin through cleavage to form thrombin. We now report that purified L-FCN-MASPs complexes, bound from serum to N-acetylcysteine-Sepharose, or MBL-MASPs complexes, bound to mannan-agarose, generate clots when incubated with calcified plasma or purified fibrinogen and factor XIII. Plasmin digestion of the clot and analysis using anti-D-dimer antibodies revealed that the clot was made up of fibrin and was similar to that generated by thrombin in normal human plasma. Fibrinopeptides A and B (FPA and FPB, respectively) were released after fibrinogen cleavage by L-FCN-MASPs complexes captured on N-acetylcysteine-Sepharose. Studies of inhibition of fibrinopeptide release indicated that the dominant pathway for clotting catalysed by the MASPs is via MASP-2 and prothrombin activation, as hirudin, a thrombin inhibitor that does not inhibit MASP-1 and MASP-2, substantially inhibits fibrinopeptide release. In the light of their potent chemoattractant effects on neutrophil and fibroblast recruitment, the MASP-mediated release of FPA and FPB may play a role in early immune activation. Additionally, MASP-catalysed deposition and polymerization of fibrin on the surface of micro-organisms may be protective by limiting the dissemination of infection.
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Published date: 2 December 2010
Keywords:
coagulation, lectin pathway, mannan-binding lectin, mannan-binding lectin-associated serine proteases
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Local EPrints ID: 159443
URI: http://eprints.soton.ac.uk/id/eprint/159443
ISSN: 0019-2805
PURE UUID: b3fea89b-8a0b-48f2-9d21-70112058f97b
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Date deposited: 30 Jun 2010 13:15
Last modified: 14 Mar 2024 01:54
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Contributors
Author:
Krishana C. Gulla
Author:
Kshitij Gupta
Author:
Anders Krarup
Author:
Peter Gal
Author:
Wilhelm J. Schwaeble
Author:
Robert B. Sim
Author:
C. David O’Connor
Author:
Krishnan Hajela
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