title: Neutrophils Contribute to the Protection Conferred by ArtinM against Intracellular Pathogens: A Study on Leishmania major.
abstract: ArtinM, a D-mannose binding lectin from Artocarpus heterophyllus, has immunomodulatory activities through its interaction with N-glycans of immune cells, culminating with the establishment of T helper type 1 (Th1) immunity. This interaction protects mice against intracellular pathogens, including Leishmania major and Leishmania amazonensis. ArtinM induces neutrophils activation, which is known to account for both resistance to pathogens and host tissue injury. Although exacerbated inflammation was not observed in ArtinM-treated animals, assessment of neutrophil responses to ArtinM is required to envisage its possible application to design a novel immunomodulatory agent based on carbohydrate recognition. Herein, we focus on the mechanisms through which neutrophils contribute to ArtinM-induced protection against Leishmania, without exacerbating inflammation. For this purpose, human neutrophils treated with ArtinM and infected with Leishmania major were analyzed together with untreated and uninfected controls, based on their ability to eliminate the parasite, release cytokines, degranulate, produce reactive oxygen species (ROS), form neutrophil extracellular traps (NETs) and change life span. We demonstrate that ArtinM-stimulated neutrophils enhanced L. major clearance and at least duplicated tumor necrosis factor (TNF) and interleukin-1beta (IL-1β) release; otherwise, transforming growth factor-beta (TGF-β) production was reduced by half. Furthermore, ROS production and cell degranulation were augmented. The life span of ArtinM-stimulated neutrophils decreased and they did not form NETs when infected with L. major. We postulate that the enhanced leishmanicidal ability of ArtinM-stimulated neutrophils is due to augmented release of inflammatory cytokines, ROS production, and cell degranulation, whereas host tissue integrity is favored by their shortened life span and the absence of NET formation. Our results reinforce the idea that ArtinM may be considered an appropriate molecular template for the construction of an efficient anti-infective agent.
authors.affiliation: Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil.
authors.forename: Rafael
authors.initials: R
authors.lastname: Ricci-Azevedo
authors.affiliation: Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil.
authors.forename: Aline Ferreira
authors.initials: AF
authors.lastname: Oliveira
authors.affiliation: Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil.
authors.forename: Marina C A V
authors.initials: MC
authors.lastname: Conrado
authors.affiliation: Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil.
authors.forename: Fernanda Caroline
authors.initials: FC
authors.lastname: Carvalho
authors.affiliation: Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Roque-Barreira
mesh_terms: D031622:Artocarpus / Q000737:chemistry; D015550:Cell Degranulation; D002470:Cell Survival; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D006801:Humans; D007155:Immunologic Factors / Q000302:isolation & purification / Q000494:pharmacology*; D037102:Lectins / Q000302:isolation & purification / Q000494:pharmacology*; D018320:Leishmania major / Q000276:immunology* / Q000502:physiology; D009504:Neutrophils / Q000187:drug effects / Q000276:immunology* / Q000469:parasitology* / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D016207:Cytokines; D007155:Immunologic Factors; D037102:Lectins; D017382:Reactive Oxygen Species