Cytotoxic and inflammatory potential of a phospholipase A2 from Bothrops jararaca snake venom

[摘要] Background Snake venom phospholipases A₂ (PLA₂s) have been reported to induce myotoxic, neurotoxic, hemolytic, edematogenic, cytotoxic and proinflammatory effects. This work aimed at the isolation and functional characterization of a PLA₂ isolated from Bothrops jararaca venom, named BJ-PLA₂-I. Methods and Results For its purification, three consecutive chromatographic steps were used (Sephacryl S-200, Source 15Q and Mono Q 5/50 GL). BJ-PLA₂-I showed acidic characteristics, with pI~ 4.4 and molecular mass of 14.2 kDa. Sequencing resulted in 60 amino acid residues that showed high similarity to other Bothrops PLA₂s, including 100% identity with BJ-PLA₂, an Asp49 PLA₂ previously isolated from B. jararaca venom. Being an Asp49 PLA₂, BJ-PLA₂-I showed high catalytic activity, and also inhibitory effects on the ADP-induced platelet aggregation. Its inflammatory characterization showed that BJ-PLA₂-I was able to promote leukocyte migration in mice at different concentrations (5, 10 and 20 μg/mL) and also at different response periods (2, 4 and 24 h), mainly by stimulating neutrophil infiltration. Furthermore, increased levels of total proteins, IL-6, IL-1β and PGE₂ were observed in the inflammatory exudate induced by BJ-PLA₂-I, while nitric oxide, TNF-α, IL-10 and LTB₄ levels were not significantly altered. This toxin was also evaluated for its cytotoxic potential on normal (PBMC) and tumor cell lines (HL-60 and HepG2). Overall, BJ-PLA₂-I (2.5–160 μg/mL) promoted low cytotoxicity, with cell viabilities mostly varying between 70 and 80% and significant values obtained for HL-60 and PBMC only at the highest concentrations of the toxin evaluated. Conclusions BJ-PLA₂-I was characterized as an acidic Asp49 PLA₂ that induces acute local inflammation and low cytotoxicity. These results should contribute to elucidate the action mechanisms of snake venom PLA₂s.

[学科分类] 药理学

[关键词] Snake venom;Bothrops jararaca;Phospholipase A 2;Inflammation;Cytotoxicity