Action of Two Phospholipases A₂ Purified from Bothrops alternatus Snake Venom on Macrophages

---

S. S. Setúbal¹, A. S. Pontes¹, J. L. Furtado¹, C. V. Xavier¹, F. L. Silva¹, A. M. Kayano², L. F. M. Izidoro³, A. M. Soares², L. A. Calderon², R. G. Stábeli^1,2, and J. P. Zuliani^1,2*

¹Laboratório de Bioquímica e Biotecnologia e Laboratório de Cultivo Celular e Anticorpos Monoclonais, Instituto de Pesquisas em Patologias Tropicais, IPEPATRO/FIOCRUZ Rondônia, Rua da Beira, 7671 BR364, Km 3.5 - CEP 76812-245 - Porto Velho-RO, Brazil; fax: 55 (69) 3219-6000; E-mail: jzuliani@pq.cnpq.br; jzuliani@ipepatro.org.br

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

DOI: 10.1134/S0006297913020089

---