2Centro de Biomoléculas Aplicadas à Saúde, Fundação Oswaldo Cruz, FIOCRUZ Rondônia e Departamento de Medicina, Universidade Federal de Rondônia, UNIR, Porto Velho-RO, Brazil
3Faculdade de Ciências Integradas do Pontal, Universidade Federal de Uberlândia, UFU, Ituiutaba-MG, Brazil
* To whom correspondence should be addressed.
Received August 11, 2012; Revision received October 1, 2012
The in vitro effects of BaltTX-I, a catalytically inactive Lys49 variant of phospholipase A2 (PLA2), and BaltTX-II, an Asp49 catalytically active PLA2 isolated from Bothrops alternatus snake venom, on thioglycollate-elicited macrophages (TG-macrophages) were investigated. At non-cytotoxic concentrations, the secretory PLA2 BaltTX-I but not BaltTX-II stimulated complement receptor-mediated phagocytosis. Pharmacological treatment of TG-macrophages with staurosporine, a protein kinase C (PKC) inhibitor, showed that this kinase is involved in the increase of serum-opsonized zymosan phagocytosis induced by BaltTX-I but not BaltTX-II secretory PLA2, suggesting that PKC may be involved in the stimulatory effect of this toxin in serum-opsonized zymosan phagocytosis. Moreover, BaltTX-I and -II induced superoxide production by TG-macrophages. This superoxide production stimulated by both PLA2s was abolished after treatment of cells with staurosporine, indicating that PKC is an important signaling pathway for the production of this radical. Our experiments showed that, at non-cytotoxic concentrations, BaltTX-I may upregulate phagocytosis via complement receptors, and that both toxins upregulated the respiratory burst in TG-macrophages.
KEY WORDS: snake venom PLA2, macrophages, phagocytosis, PKC, superoxide, inflammation