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J Leukoc Biol. 2016 Oct;100(4):801-810. Epub 2016 May 6.

Neutrophil extracellular traps release induced by Leishmania: role of PI3Kγ, ERK, PI3Kσ, PKC, and [Ca2+].

Author information

1
Laboratório de Imunobiologia das Leishmanioses, Departamento de Imunologia, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Brazil.
2
Laboratório de Imunobiofísica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil.
3
Laboratório de Neurogênese, Departamento de Neurobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil; and Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fiocruz, Brazil.
4
Laboratório de Imunobiologia das Leishmanioses, Departamento de Imunologia, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Brazil; esaraiva@micro.ufrj.br.

Abstract

Upon in vitro stimulation, neutrophils undergo a cell death named netosis. This process is characterized by extracellular release of chromatin scaffold associated with granular and cytoplasmic proteins, which together, ensnare and kill microbes. We have previously described that interaction of Leishmania amazonensis with human neutrophils leads to the release of neutrophil extracellular traps, which trap and kill the parasite. However, the signaling leading to Leishmania induced netosis is still unknown. Thus, we sought to evaluate signaling events that drive L. amazonensis induced neutrophil extracellular trap release from human neutrophils. Here, we found that PI3K, independently of protein kinase B, has a role in parasite-induced netosis. We also described that the main isoforms involved are PI3Kγ and PI3Kδ, which work in reactive oxygen species-dependent and -independent ways, respectively. We demonstrated that activation of ERK downstream of PI3Kγ is important to trigger reactive oxygen species-dependent, parasite-induced netosis. Pharmacological inhibition of protein kinase C also significantly decreased parasite-induced neutrophil extracellular trap release. Intracellular calcium, regulated by PI3Kδ, represents an alternative reactive oxygen species-independent pathway of netosis stimulated by L. amazonensis Finally, intracellular calcium mobilization and reactive oxygen species generation are the major regulators of parasite-induced netosis. Our results contribute to a better understanding of the signaling behind netosis induced by interactions between Leishmania and neutrophils.

KEYWORDS:

netosis; parasitic protozoa; signaling

PMID:
27154356
PMCID:
PMC5014744
DOI:
10.1189/jlb.4A0615-261RR
[Indexed for MEDLINE]
Free PMC Article

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