Structural and pharmacological characterization of toxins isolated from Bothrops bilineatus smaragdinus (forest viper) venom with potential modulatory activity of the motor synaptic release and cardiovascular functions

• Grant number: 20/04287-6
• Support Opportunities: BIOTA-FAPESP Program - Regular Research Grants
• Start date: August 01, 2021
• End date: January 31, 2024
• Field of knowledge: Biological Sciences - Pharmacology - Toxicology
• Principal Investigator: Rafael Stuani Floriano
• Grantee: Rafael Stuani Floriano
• Host Institution: Pró-Reitoria de Pesquisa e Pós-Graduação. Universidade do Oeste Paulista (UNOESTE). Presidente Prudente , SP, Brazil
• Associated researchers: Bruno Lomonte ; Edward Gerard Rowan ; Francis Lopes Pacagnelli ; Stephen Hyslop

Abstract

Envenomation by lancehead snakes (genus Bothrops) is characterized by cardiovascular effects (coagulopathy, systemic hemorrhage, hypotension/shock and acute kidney injury) mediated by enzymes such as L-amino acid oxidases, C-type lectins, serine proteinases, metalloproteinases and phospholipases A2 (PLA2), with the some of the latter acting as b-neurotoxins to cause presynaptic neuromuscular blockade. The cardiovascular effects of envenomation by Bothrops spp. are considered the principal cause of death, with little peripheral neurotoxicity. The toxinology of Bothrops bilineatus smaragdinus venom has not been systematically studied. In this project, we intend to purify and structurally and pharmacologically characterize presynaptic neurotoxins from this venom and examine their ability to modulate cardiovascular functions in vitro. Initially, the venom will be fractionated by gel filtration to obtain fraction P-3 that will then be purified using RP-HPLC; the resulting toxins will be screened for neurotoxicity in mouse isolated phrenic nerve-diaphragm (PND) preparations in vitro. The toxins will also be assessed for enzymatic and cytotoxic activities followed by molecular identification through sequencing with mass spectrometry. The mechanisms involved in the neuromuscular effects of the principal neurotoxins will be examined using a variety of electrophysiological approaches, including intracellular (evoked and spontaneous end-plate potentials) and extracellular (compound action potentials) recordings in mouse nerve-muscle preparations, as well as ion current (whole cell patch-clamp) recordings in primary cultures of ganglion neurons. The cardiac (rat isolated atria) and vascular (rat isolated thoracic aorta) actions of the toxins will also be assessed in vitro. The results of this work will contribute to our understanding of the mechanisms involved in envenomation by this specie and allow the characterization of toxins with a potential modulatory action of neuronal and cardiovascular functions. (AU)

Scientific publications

(5)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

SILVA-CARVALHO, ROSIMEIRE; GASPAR, MATHEUS Z.; QUADROS, LUIZ H. B.; LOBO, LUIS G. G.; SANTAR, CECILIA L.; SILVA, ELISANGELA O.; GEREZ, JULIANA R.; SILVA JR, NELSON J.; HYSLOP, STEPHEN; LOMONTE, BRUNO; et al.

Partial efficacy of a Brazilian coralsnake antivenom and varespladib in neutralizing distinct toxic effects induced by sublethal Micrurus dumerilii carinicauda envenoming in rats

. Toxicon, v. 213, p. 6-pg., 2022-07-15. (20/14191-6, 20/04287-6)

COUCEIRO, FERNANDA Y. G. M.; DEMICO, POLIANA J.; DIAS, SAMUEL R.; OLIVEIRA, ISABELE N.; PACAGNELLI, FRANCIS L.; SILVA, ELISANGELA O.; SANT'ANNA, SAVIO S.; GREGO, KATHLEEN F.; MORAIS-ZANI, KAREN; TORRES-BONILLA, KRISTIAN A.; et al. Involvement of phospholipase A2 in the neuromuscular blockade caused by coralsnake (Micrurus spp.) venoms in mouse phrenic nerve-diaphragm preparations in vitro. Toxicon, v. 234, p. 8-pg., 2023-10-01. (20/04287-6, 20/07268-2, 23/01961-6, 22/05878-3)

GASPAR, MATHEUS Z.; YABUNAKA, ANA C.; SILVA-CARVALHO, ROSIMEIRE; NASCIMENTO, CHARLES U.; BRINHOLI, REJANE B.; SILVA, ELISANGELA O.; GEREZ, JULIANA R.; SILVA JR, NELSON J.; TORRES-BONILLA, KRISTIAN A.; HYSLOP, STEPHEN; et al. Cardiac Effects of Micrurus corallinus and Micrurus dumerilii carinicauda (Elapidae) Venoms and Neutralization by Brazilian Coralsnake Antivenom and Varespladib. Cardiovascular Toxicology, v. 23, n. 3-4, p. 15-pg., 2023-02-22. (16/11344-0, 20/14191-6, 20/04287-6)

GUTIERRES, PAMELLA G.; PEREIRA, DIEGO R.; VIEIRA, NATALY L.; ARANTES, LILIAN F.; SILVA, JR., NELSON J.; TORRES-BONILLA, KRISTIAN A.; HYSLOP, STEPHEN; MORAIS-ZANI, KAREN; NOGUEIRA, ROSA M. B.; ROWAN, EDWARD G.; et al. ction of Varespladib (LY-315920), a Phospholipase A(2) Inhibitor, on the Enzymatic, Coagulant and Haemorrhagic Activities of Lachesis muta rhombeata (South-American Bushmaster) Veno. FRONTIERS IN PHARMACOLOGY, v. 12, JAN 12 2022. (20/11268-8, 20/04287-6)

SILVA-CARVALHO, ROSIMEIRE; GASPAR, MATHEUS Z.; QUADROS, LUIZ H. B.; LOBO, LUIS G. G.; ROGERIO, LETICIA M.; SANTOS, NAJLA T. S.; ZERBINATTI, MARIA C.; SANTAREM, CECILIA L.; SILVA, ELISANGELA O.; GEREZ, JULIANA R.; et al. In vivo treatment with varespladib, a phospholipase A(2) inhibitor, prevents the peripheral neurotoxicity and systemic disorders induced by Micrurus corallinus (coral snake) venom in rats. Toxicology Letters, v. 356, p. 10-pg., 2022-03-01. (20/04287-6, 20/14191-6)