title: Exploiting the antithrombotic effect of the (pro)thrombin inhibitor bothrojaracin.
abstract: Bothrojaracin is a 27 kDa C-type lectin-like protein from Bothrops jararaca snake venom. It behaves as a potent thrombin inhibitor upon high-affinity binding to thrombin exosites. Bothrojaracin also forms a stable complex with prothrombin that can be detected in human plasma. Formation of the zymogen-inhibitor complex severely decreases prothrombin activation and contributes to the anticoagulant activity of bothrojaracin. In the present study, we employed two rodent models to evaluate the antithrombotic effect of bothrojaracin in vivo: stasis-induced thrombosis and thrombin-induced pulmonary thromboembolism. It was observed that bothrojaracin interacts with rat prothrombin in plasma. Ex-vivo assays showed stable complex formation even after 24 h of a single bothrojaracin dose. As a result, bothrojaracin showed significant antithrombotic activity in a rat venous thrombosis model elicited by thromboplastin combined with stasis. The antithrombotic activity of bothrojaracin (1 mg/kg) persisted for up to 24 h and it was associated with moderate bleeding as assessed by a tail transection method. Formation of bothrojaracin-prothrombin complex has been also observed following intravenous administration of the inhibitor into mice. As a result, bothrojaracin effectively protected mice from thrombin-induced fatal thromboembolism. We conclude that bothrojaracin is a potent antithrombotic agent in vivo and may serve as a prototype for the development of new zymogen-directed drugs that could result in prolonged half-life and possible decreased hemorrhagic risk.
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Mariane
authors.initials: M
authors.lastname: Assafim
authors.affiliation: Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Flávia S
authors.initials: FS
authors.lastname: Frattani
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Marcos S
authors.initials: MS
authors.lastname: Ferreira
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Dione M
authors.initials: DM
authors.lastname: Silva
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Robson Q
authors.initials: RQ
authors.lastname: Monteiro
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil. Electronic address: lzingali@bioqmed.ufrj.br.
authors.forename: Russolina B
authors.initials: RB
authors.lastname: Zingali
mesh_terms: D000818:Animals; D000991:Antithrombins / Q000633:toxicity*; D003435:Crotalid Venoms / Q000633:toxicity*; D005260:Female; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011516:Prothrombin / Q000037:antagonists & inhibitors*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000991:Antithrombins; D003435:Crotalid Venoms; C083739:bothrojaracin; D011516:Prothrombin
keywords: Bothrojaracin; Bothrops jararaca venom; Thrombin inhibitor; Thrombosis