Life-threatening thrombosis in mice with targeted Arg48-to-Cys mutation of the heparin-binding domain of antithrombin.
Antithrombin (AT) inhibits thrombin and some other coagulation factors in a reaction that is dramatically accelerated by binding of a pentasaccharide sequence present in heparin/heparan-sulfate to a heparin-binding site on AT. Based on the involvement of R47 in the heparin/AT interaction and the frequent occurrence of R47 mutations in AT deficiency patients, targeted knock-in of the corresponding R48C substitution in AT in mice was performed to generate a murine model of spontaneous thrombosis. The mutation efficiently abolished the effect of heparin-like molecules on coagulation inhibition in vitro and in vivo. Mice homozygous for the mutation (AT(m/m) mice) developed spontaneous, life-threatening thrombosis, occurring as early as the day of birth. Only 60% of the AT(m/m) offspring reached weaning age, with further loss at different ages. Thrombotic events in adult homozygotes were most prominent in the heart, liver, and in ocular, placental, and penile vessels. In the neonate, spontaneous death invariably was associated with major thrombosis in the heart. This severe thrombotic phenotype underlines a critical function of the heparin-binding site of antithrombin and its interaction with heparin/heparan-sulfate moieties in health, reproduction, and survival, and represents an in vivo model for comparative analysis of heparin-derived and other antithrombotic molecules.
Center for Transgene Technology and Gene Therapy, VIB, KULeuven Campus Gasthuisberg O&N, Herestraat 49, B-3000 Leuven, Belgium. mieke.dewerchin@med.kuleuven.ac.be
Mieke
M
Dewerchin
Jean-Pascal
JP
Hérault
Goedele
G
Wallays
Maurice
M
Petitou
Paul
P
Schaeffer
Laurence
L
Millet
Jeffrey I
JI
Weitz
Lieve
L
Moons
Désiré
D
Collen
Peter
P
Carmeliet
Jean-Marc
JM
Herbert
D019943:Amino Acid Substitution; D000818:Animals; D000991:Antithrombins / Q000235:genetics*; D001665:Binding Sites / Q000235:genetics; D025861:Blood Coagulation Disorders, Inherited / Q000235:genetics* / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D005328:Fetal Viability / Q000235:genetics; D018390:Gene Targeting; D006487:Hemostasis / Q000235:genetics; D006493:Heparin / Q000378:metabolism*; D006720:Homozygote; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D009154:Mutation; D015996:Survival Rate; D013927:Thrombosis / Q000235:genetics* / Q000473:pathology
D000991:Antithrombins; D006493:Heparin