Abstract
Macrophages act as the primary effector cells during Leishmania infection through production of reactive oxygen species (ROS) and interleukin-1β (IL-1β). However, how macrophage-killing mechanisms are activated during Leishmania-macrophage interactions is poorly understood. Here, we report that the macrophage response against Leishmania infantum in vivo is characterized by an M2b-like phenotype and C-type lectin receptors (CLRs) signature composed of Dectin-1, mannose receptor (MR), and the DC-SIGN homolog SIGNR3 expression. Dectin-1 and MR were crucial for the microbicidal response as indicated by the fact that they activated Syk-p47phox and arachidonic acid (AA)-NADPH oxidase signaling pathways, respectively, needed for ROS production and also triggered Syk-coupled signaling for caspase-1-induced IL-1β secretion. In contrast, SIGNR3 has divergent functions during Leishmania infantum pathogenesis; this CLR favored parasite resilience through inhibition of the LTB4-IL-1β axis. These pathways also operated during infection of primary human macrophages. Therefore, our study promotes CLRs as potential targets for treatment, diagnosis, and prevention of visceral leishmaniasis.
Copyright © 2013 Elsevier Inc. All rights reserved.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antigens, CD / metabolism*
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Arachidonic Acid / metabolism
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Caspase 1 / metabolism
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Cells, Cultured
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Humans
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Interleukin-1beta / antagonists & inhibitors
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Interleukin-1beta / metabolism
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Intracellular Signaling Peptides and Proteins / metabolism
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Lectins, C-Type / immunology
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Lectins, C-Type / metabolism*
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Leishmania infantum / immunology*
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Leishmaniasis, Visceral / immunology
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Leishmaniasis, Visceral / parasitology
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Leukotriene B4 / antagonists & inhibitors
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Macrophages / immunology*
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Mannose Receptor
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Mannose-Binding Lectins / metabolism*
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Mice
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Mice, Inbred C57BL
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Mice, Knockout
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NADPH Oxidases / metabolism
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Protein-Tyrosine Kinases / metabolism
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RNA Interference
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RNA, Small Interfering
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Reactive Oxygen Species / metabolism
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Receptors, Cell Surface / metabolism*
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Signal Transduction
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Syk Kinase
Substances
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Antigens, CD
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Interleukin-1beta
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Intracellular Signaling Peptides and Proteins
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Lectins, C-Type
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Mannose Receptor
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Mannose-Binding Lectins
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RNA, Small Interfering
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Reactive Oxygen Species
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Receptors, Cell Surface
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SIGNR3 protein, mouse
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dectin 1
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Leukotriene B4
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Arachidonic Acid
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NADPH Oxidases
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neutrophil cytosolic factor 1
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Protein-Tyrosine Kinases
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SYK protein, human
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Syk Kinase
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Syk protein, mouse
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Caspase 1