Presynaptic Proteins as Markers of the Neurotoxic Activity of BmjeTX-I and BmjeTX-II Toxins from Bothrops marajoensis (Marajo Lancehead) Snake Venom

Autor(es)

Lisboa, Antonio ; Melare, Rodolfo ; Franco, Junia R. B. ; Bis, Carolina V. ; Gracia, Marta ; Ponce-Soto, Luis A. ; Marangoni, Sergio ; Rodrigues-Simioni, Lea ; da Cruz-Hofling, Maria Alice ; Rocha, Thalita

• Tipo de documento: Artigo Científico
• Fonte: BIOCHEMISTRY RESEARCH INTERNATIONAL; v. 2016, p. 10-pg., 2016-01-01.

Resumo

Neuromuscular preparations exposed to B. marajoensis venom show increases in the frequency of miniature end-plate potentials and twitch tension facilitation followed by presynaptic neuromuscular paralysis, without evidences of muscle damage. Considering that presynaptic toxins interfere into the machinery involved in neurotransmitter release (synaptophysin, synaptobrevin, and SNAP25 proteins), the main objective of this communication is to analyze, by immunofluorescence and western blotting, the expression of the synaptic proteins, synaptophysin, synaptobrevin, and SNAP25 and by myography, light, and transmission electron microscopy the pathology of motor nerve terminals and skeletal muscle fibres of chick biventer cervicis preparations (CBC) exposed in vitro to BmjeTX-I and BmjeTX-II toxins from B. marajoensis venom. CBC incubated with toxins showed irreversible twitch tension blockade and unaffected KCl- and ACh-evoked contractures, and the positive colabelling of acetylcholine receptors confirmed that their action was primarily at the motor nerve terminal. Hypercontraction and loose myofilaments and synaptic vesicle depletion and motor nerve damage indicated that the toxins displayed both myotoxic and neurotoxic effect. The blockade resulted from interference on synaptophysin, synaptobrevin, and SNAP25 proteins leading to the conclusion that BmjeTX-I and BmjeTX-II affected neurotransmitter release machinery by preventing the docking of synaptic vesicles to the axolemma of the nerve terminal. (AU)

• Processo FAPESP: 11/00001-1 - Aspectos moleculares da junção neuromuscular sob o efeito de venenos e toxinas botrópicas com ação pré-sináptica
• Beneficiário: Thalita Rocha
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 05/53625-1 - Ação dos mastoparanos e da fosfolipase A2 isolados do veneno de Polybia paulista (Hymenoptera, Epiponini) nos mecanismos de apoptose e necrose de células musculares e mitocôndrias isoladas de camundongos Balb/c
• Beneficiário: Maria Alice da Cruz Hofling
• Modalidade de apoio: Auxílio à Pesquisa - Regular