Involvement of von Willebrand factor and botrocetin in the thrombocytopenia induced by Bothrops jararaca snake venom

Autor(es)

Thomazini, Camila Martos ^{[1, 2]} ; Sachetto, Ana Teresa Azevedo ^{[1, 2]} ; de Albuquerque, Cynthia Zaccanini ^[3] ; de Moura Mattaraia, Vania Gomes ^[3] ; de Oliveira, Ana Karina ^[4] ; Serrano, Solange Maria de Toledo ^[4] ; Lebrun, Ivo ^[5] ; Barbaro, Katia Cristina ^[6] ; Santoro, Marcelo Larami ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Inst Butantan, Lab Fisiopatol, Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Fac Med, Programa Posgrad Clin Med, Sao Paulo, SP - Brazil

^[3] Inst Butantan, Bioterio Cent, Sao Paulo, SP - Brazil

^[4] Inst Butantan, Ctr Toxins Immune Response & Cell Signaling CeTIC, Lab Toxinol Aplicada, Sao Paulo, SP - Brazil

^[5] Inst Butantan, Lab Bioquim & Biofis, Sao Paulo, SP - Brazil

^[6] Inst Butantan, Lab Imunopatol, Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PLoS Neglected Tropical Diseases; v. 15, n. 9 SEP 2021.
• Citações Web of Science: 0

Resumo

Author summary Envenomation by snakebites is a major burden to tropical and subtropical areas in the world. Many snake species produce venoms that, when injected into victims, cause bleedings and other associated symptoms and signs. This work aimed to understand the mechanisms that lead to a fall in blood platelet counts after bites by a snake that inhabits in southeastern Brazil, the lance-headed snake Bothrops jararaca (popularly known as jararaca). We used experimental approaches to understand the involvement of a protein from jararaca venom, called botrocetin, and a protein present in our blood (von Willebrand factor) in the fall of platelet counts. We observed that botrocetin alters von Willebrand factor, but this mechanism in not important for the decrease in platelet counts. We show that jararaca snake venom disturb blood platelets in a complex and intricate way, and that other venom compounds are involved in the decrease of platelet counts during snakebite envenomation. Patients bitten by snakes consistently manifest a bleeding tendency, in which thrombocytopenia, consumption coagulopathy, mucous bleeding, and, more rarely, thrombotic microangiopathy, are observed. Von Willebrand factor (VWF) is required for primary hemostasis, and some venom proteins, such as botrocetin (a C-type lectin-like protein) and snake venom metalloproteinases (SVMP), disturb the normal interaction between platelets and VWF, possibly contributing to snakebite-induced bleedings. To understand the relationship among plasma VWF, platelets, botrocetin and SVMP from Bothrops jararaca snake venom (BjV) in the development of thrombocytopenia, we used (a) Wistar rats injected s.c. with BjV preincubated with anti-botrocetin antibodies (ABA) and/or Na-2-EDTA (a SVMP inhibitor), and (b) VWF knockout mice (Vwf(-/-)) injected with BjV. Under all conditions, BjV induced a rapid and intense thrombocytopenia. In rats, BjV alone reduced the levels of VWF:Ag, VWF:CB, high molecular weight multimers of VWF, ADAMTS13 activity, and factor VIII. Moreover, VWF:Ag levels in rats that received BjV preincubated with Na-2-EDTA and/or ABA tended to recover faster. In mice, BjV caused thrombocytopenia in both Vwf(-/-) and C57BL/6 (background control) strains, and VWF:Ag levels tended to decrease in C57BL/6, demonstrating that thrombocytopenia was independent of the presence of plasma VWF. These findings showed that botrocetin present in BjV failed to affect the extent or the time course of thrombocytopenia induced by envenomation, but it contributed to decrease the levels and function of plasma VWF. Thus, VWF alterations during B. jararaca envenomation are an ancillary event, and not the main mechanism leading to decreased platelet counts. (AU)

• Processo FAPESP: 13/07467-1 - CeTICS - Centro de Toxinas, Imuno-Resposta e Sinalização Celular
• Beneficiário: Hugo Aguirre Armelin
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 18/26015-8 - Novos mecanismos de patogênese da Sepse e do envenenamento botrópico: potencial da rutina como agente terapêutico
• Beneficiário: Ana Teresa Azevedo Sachetto
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 13/20239-8 - Alterações do fator de Von Willebrand e da síntese hepática de fatores hemostáticos em envenenamento experimental pela serpente Bothrops Jararaca
• Beneficiário: Camila Martos Thomazini
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 19/07618-6 - Interação hemostasia-inflamação no envenenamento pela serpente Bothrops jararaca: patogênese da plaquetopenia e mecanismos terapêuticos antiofídicos da quercetina-3-rutinosídeo (rutina)
• Beneficiário: Marcelo Larami Santoro
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 13/25177-0 - Envolvimento do fator de Von Willebrand nos distúrbios hemostáticos do envenenamento pela serpente Bothrops jararaca: estudo experimental
• Beneficiário: Marcelo Larami Santoro
• Modalidade de apoio: Auxílio à Pesquisa - Regular