Normal levels of anticoagulant heparan sulfate are not essential for normal hemostasis.
Endothelial cell production of anticoagulant heparan sulfate (HS(act)) is controlled by the Hs3st1 gene, which encodes the rate-limiting enzyme heparan sulfate 3-O-sulfotransferase-1 (3-OST-1). In vitro, HS(act) dramatically enhances the neutralization of coagulation proteases by antithrombin. The in vivo role of HS(act) was evaluated by generating Hs3st1(-/-) knockout mice. Hs3st1(-/-) animals were devoid of 3-OST-1 enzyme activity in plasma and tissue extracts. Nulls showed dramatic reductions in tissue levels of HS(act) but maintained wild-type levels of tissue fibrin accumulation under both normoxic and hypoxic conditions. Given that vascular HS(act) predominantly occurs in the subendothelial matrix, mice were subjected to a carotid artery injury assay in which ferric chloride administration induces de-endothelialization and occlusive thrombosis. Hs3st1(-/-) and Hs3st1(+/+) mice yielded indistinguishable occlusion times and comparable levels of thrombin.antithrombin complexes. Thus, Hs3st1(-/-) mice did not show an obvious procoagulant phenotype. Instead, Hs3st1(-/-) mice exhibited genetic background-specific lethality and intrauterine growth retardation, without evidence of a gross coagulopathy. Our results demonstrate that the 3-OST-1 enzyme produces the majority of tissue HS(act). Surprisingly, this bulk of HS(act) is not essential for normal hemostasis in mice. Instead, 3-OST-1-deficient mice exhibited unanticipated phenotypes suggesting that HS(act) or additional 3-OST-1-derived structures may serve alternate biologic roles.
HajMohammadi
Sassan
S
Section of Cardiology, Department of Medicine, Dartmouth Medical School, Hanover, New Hampshire, USA.
Enjyoji
Keiichi
K
Princivalle
Marc
M
Christi
Patricia
P
Lech
Miroslav
M
Beeler
David
D
Rayburn
Helen
H
Schwartz
John J
JJ
Barzegar
Samad
S
de Agostini
Ariane I
AI
Post
Mark J
MJ
Rosenberg
Robert D
RD
Shworak
Nicholas W
NW
D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology*; D000991:Antithrombins / Q000378:metabolism; D002339:Carotid Arteries / Q000473:pathology; D003433:Crosses, Genetic; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology; D005091:Exons; D005260:Female; D005838:Genotype; D006487:Hemostasis; D006497:Heparan Sulfate / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008957:Models, Genetic; D012190:Retroviridae / Q000235:genetics; D015238:Sulfotransferases / Q000378:metabolism; D013917:Thrombin / Q000378:metabolism; D014018:Tissue Distribution
D000925:Anticoagulants; D000991:Antithrombins; D006497:Heparan Sulfate; D015238:Sulfotransferases; D013917:Thrombin; C102180:heparan sulfate D-glucosaminyl 3-O-sulfotransferase