title: Functional analysis of fibrin {gamma}-chain cross-linking by activated factor XIII: determination of a cross-linking pattern that maximizes clot stiffness.
abstract: Activated coagulation factor XIII (FXIIIa) cross-links the gamma-chains of fibrin early in clot formation. Cross-linking of the alpha-chains occurs more slowly, leading to high molecular weight multimer formations that can also contain gamma-chains. To study the contribution of FXIIIa-induced gamma-chain cross-linking on fibrin structure and function, we created 2 recombinant fibrinogens (gammaQ398N/Q399N/K406R and gammaK406R) that modify the gamma-chain cross-linking process. In gammaK406R, gamma-dimer cross-links were absent, but FXIIIa produced a cross-linking pattern similar to that observed in tissue transglutaminase cross-linked fibrin(ogen) with mainly alpha-gamma cross-links. In Q398N/Q399N/K406R, cross-links with any gamma-chain involvement were completely absent, and only alpha-chain cross-linking occurred. Upon cross-linking, recombinant normal fibrin yielded a 3.5-fold increase in stiffness, compared with a 2.5-fold increase by alpha-chain cross-linking alone (gammaQ398N/Q399N/K406R). gammaK406R fibrin showed a 1.5-fold increase in stiffness after cross-linking. No major differences in clot morphology, polymerization, and lysis rates were observed, although fiber diameter was slightly lower in cross-linked normal fibrin relative to the variants. Our results show that gamma-chain cross-linking contributes significantly to clot stiffness, in particular through gamma-dimer formation; alpha-gamma hybrid cross-links had the smallest impact on clot stiffness.
authors: Academic Unit of Molecular Vascular Medicine, Leeds Institute for Genetics, Health and Therapeutics, Clarendon Way, University of Leeds, UK.
authors: Kristina F
authors: KF
authors: Standeven
authors: Angela M
authors: AM
authors: Carter
authors: Peter J
authors: PJ
authors: Grant
authors: John W
authors: JW
authors: Weisel
authors: Irina
authors: I
authors: Chernysh
authors: Leona
authors: L
authors: Masova
authors: Susan T
authors: ST
authors: Lord
authors: Robert A S
authors: RA
authors: Ariëns
mesh_terms: D019943:Amino Acid Substitution; D026122:Factor XIIIa / Q000737:chemistry*; D005337:Fibrin / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D006801:Humans; D046912:Multiprotein Complexes / Q000032:analysis*; D020125:Mutation, Missense; D011994:Recombinant Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics
chemical_list: D046912:Multiprotein Complexes; D011994:Recombinant Proteins; D005337:Fibrin; D026122:Factor XIIIa