Melittin induces in vitro death of Leishmania (Leishmania) infantum by triggering the cellular innate immune response

 

Andreia Vieira Pereira¹, Gustavo de Barros¹, Erika Gracielle Pinto^2 3, Andre Gustavo Tempone², Ricardo de Oliveira Orsi^{4 5}, Lucilene Delazari dos Santos^1 5, Sueli Calvi^1 5, Rui Seabra Ferreira Jr^1 5, Daniel Carvalho Pimenta⁶ , Benedito Barraviera^1 5

 

1 Graduate Program in Tropical Diseases, Botucatu Medical School, São Paulo State University (UNESP - Univ Estadual Paulista), Botucatu, SP, Brazil.

2 Department of Parasitology, Adolfo Lutz Institute, São Paulo, SP, Brazil.

3 Laboratory of Protozoology, Institute for Tropical Medicine, University of São Paulo (USP), São Paulo, SP, Brazil.

4 Department of Animal Production, School of Veterinary Medicine and Animal Husbandry, São Paulo State University (UNESP - Univ Estadual Paulista), Botucatu, SP, Brazil.

5 Center for the Study of Venoms and Venomous Animals (CEVAP), São Paulo State University (UNESP - Univ Estadual Paulista), Rua José Barbosa de Barros, 1780, 18610-307, Botucatu, SP, Brazil.

6 Laboratory of Biochemistry and Biophysics, Butantan Institute, São Paulo, SP, Brazil.

 

ABSTRACT

Background

Apis mellifera venom, which has already been recommended as an alternative anti-inflammatory treatment, may be also considered an important source of candidate molecules for biotechnological and biomedical uses, such as the treatment of parasitic diseases.

Methods

Africanized honeybee venom from Apis mellifera was fractionated by RP-C18-HPLC and the obtained melittin was incubated with promastigotes and intracellular amastigotes of Leishmania (L.) infantum. Cytotoxicity to mice peritoneal macrophages was evaluated through mitochondrial oxidative activity. The production of anti- and pro-inflammatory cytokines, NO and H₂O₂ by macrophages was determined.

Results

Promastigotes and intracellular amastigotes were susceptible to melittin (IC₅₀ 28.3 μg.mL⁻¹ and 1.4 μg.mL⁻¹, respectively), but also showed mammalian cell cytotoxicity with an IC₅₀ value of 5.7 μg.mL⁻¹. Uninfected macrophages treated with melittin increased the production of IL-10, TNF-α, NO and H₂O₂. Infected melittin-treated macrophages increased IL-12 production, but decreased the levels of IL-10, TNF-α, NO and H₂O₂.

Conclusions

The results showed that melittin acts in vitro against promastigotes and intracellular amastigotes of Leishmania (L.) infantum. Furthermore, they can act indirectly on intracellular amastigotes through a macrophage immunomodulatory effect.

 

Key words: Melittin; Apis mellifera; Leishmania; Leishmaniasis; Peptides; Toxins; Antiparasitic; Cytokines

 

Ethics committee approval

The present study was approved by the Ethics Committee on Animal Experimentation of the Botucatu Medical School, São Paulo State University (UNESP), Botucatu, SP, Brazil, under protocol number CEEA 8932011 on 07/28/2011. Moreover, animal procedures were performed in agreement with the Guide for the Care and Use of Laboratory Animals from the National Academy of Sciences.

 

Received: August 7, 2015.

Revised: January 4, 2016.

Accepted: January 8, 2016.

 

Correspondence: bbviera@gnosis.com.br

 

Competing interests

The authors declare that they have no competing interests.

 

Authors’ contributions

AVP, AGT, ROO, EGP, DCP, LDS, SAC and GACB conceived, designed and performed the experiments; DCP, EGP, AGT, RSF Jr. and BB analyzed the results and wrote the paper. All authors read and approved the final manuscript.

 

doi: 10.1186/s40409-016-0055-x