title: Salivary Thromboxane A2-Binding Proteins from Triatomine Vectors of Chagas Disease Inhibit Platelet-Mediated Neutrophil Extracellular Traps (NETs) Formation and Arterial Thrombosis.
abstract: BACKGROUND
  The saliva of blood-feeding arthropods contains a notable diversity of molecules that target the hemostatic and immune systems of the host. Dipetalodipin and triplatin are triatomine salivary proteins that exhibit high affinity binding to prostanoids, such as TXA2, thus resulting in potent inhibitory effect on platelet aggregation in vitro. It was recently demonstrated that platelet-derived TXA2 mediates the formation of neutrophil extracellular traps (NETs), a newly recognized link between inflammation and thrombosis that promote thrombus growth and stability.
  
  
  RESULTS
  This study evaluated the ability of dipetalodipin and triplatin to block NETs formation in vitro. We also investigated the in vivo antithrombotic activity of TXA2 binding proteins by employing two murine models of experimental thrombosis. Remarkably, we observed that both inhibitors abolished the platelet-mediated formation of NETs in vitro. Dipetalodipin and triplatin significantly increased carotid artery occlusion time in a FeCl3-induced injury model. Treatment with TXA2-binding proteins also protected mice from lethal pulmonary thromboembolism evoked by the intravenous injection of collagen and epinephrine. Effective antithrombotic doses of dipetalodipin and triplatin did not increase blood loss, which was estimated using the tail transection method.
  
  
  CONCLUSIONS
  Salivary TXA2-binding proteins, dipetalodipin and triplatin, are capable to prevent platelet-mediated NETs formation in vitro. This ability may contribute to the antithrombotic effects in vivo. Notably, both molecules inhibit arterial thrombosis without promoting excessive bleeding. Our results provide new insight into the antihemostatic effects of TXA2-binding proteins and may have important significance in elucidating the mechanisms of saliva to avoid host's hemostatic responses and innate immune system.
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Daniella M
authors.initials: DM
authors.lastname: Mizurini
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Jorgeane S
authors.initials: JS
authors.lastname: Aslan
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Tainá
authors.initials: T
authors.lastname: Gomes
authors.affiliation: Vector Molecular Biology Section, Laboratory of Malaria and Vector Research (LMVR), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, United States of America.
authors.forename: Dongying
authors.initials: D
authors.lastname: Ma
authors.affiliation: Vector Molecular Biology Section, Laboratory of Malaria and Vector Research (LMVR), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, United States of America.
authors.forename: Ivo M B
authors.initials: IM
authors.lastname: Francischetti
authors.affiliation: Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Robson Q
authors.initials: RQ
authors.lastname: Monteiro
mesh_terms: D000818:Animals; D060829:Arthropod Proteins / Q000378:metabolism / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects; D014355:Chagas Disease / Q000635:transmission; D065206:Extracellular Traps / Q000187:drug effects / Q000502:physiology; D005260:Female; D006801:Humans; D007303:Insect Vectors / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009504:Neutrophils / Q000187:drug effects; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000378:metabolism / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D011994:Recombinant Proteins; D012471:Salivary Proteins and Peptides / Q000378:metabolism / Q000494:pharmacology*; D013927:Thrombosis / Q000517:prevention & control*; D013928:Thromboxane A2 / Q000378:metabolism*; D014225:Triatominae / Q000378:metabolism*
chemical_list: D060829:Arthropod Proteins; D010975:Platelet Aggregation Inhibitors; D011994:Recombinant Proteins; D012471:Salivary Proteins and Peptides; D013928:Thromboxane A2