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1.
Parasitology ; 146(6): 716-727, 2019 May.
Article in English | MEDLINE | ID: mdl-30588899

ABSTRACT

Leishmania (Viannia) guyanensis is one species that causes cutaneous leishmaniasis in the New World. The incidence of infections with this parasite is probably underestimated and few studies exist on this species, despite its epidemiological importance. In particular, there are no studies concerning L. guyanensis metacyclogenesis and no technique for obtaining metacyclic promastigotes for this species is presently available. Here, we have studied L. guyanensis metacyclogenesis in axenic culture, describing the main changes that occur during this process, namely, in morphology and size, sensitivity to complement-mediated lysis, surface carbohydrates and infectivity to macrophages. We have shown that metacyclogenesis in L. guyanensis promastigotes is basically complete on the 4th day of culture, as determined by decreased body size, increased flagellum length, resistance to complement-mediated lysis and infectivity. We have also found that only a fraction of the parasites is agglutinated by Bauhinia purpurea lectin. The non-agglutinated parasites, which also peaked on the 4th day of culture, had all morphological traits typical of the metacyclic stage. This is the first report describing metacyclogenesis in L. guyanensis axenic promastigotes and a simple and efficient method for the purification of metacyclic forms. Furthermore, a model of human macrophage infection with L. guyanensis was established.

2.
J Nutr Biochem ; 34: 99-105, 2016 08.
Article in English | MEDLINE | ID: mdl-27261536

ABSTRACT

Butyrate is a 4-carbon fatty acid that has antiinflammatory and antioxidative properties. It has been demonstrated that butyrate is able to reduce atherosclerotic development in animal models by reducing inflammatory factors. However, the contribution of its antioxidative effects of butyrate on atherogenesis has not yet been studied. We investigated the influence of butyrate on oxidative status, reactive oxygen species (ROS) release and oxidative enzymes (NADPH oxidase and iNOS) in atherosclerotic lesions of ApoE(-/-) mice and in oxLDL-stimulated peritoneal macrophages and endothelial cells (EA.hy926). The lesion area in aorta was reduced while in the aortic valve, although lesion area was unaltered, superoxide production and protein nitrosylation were reduced in butyrate-supplemented mice. Peritoneal macrophages from the butyrate group presented a lower free radical release after zymosan stimulus. When endothelial cells were pretreated with butyrate before oxLDL stimulus, the CCL-2 and superoxide ion productions and NADPH oxidase subunit p22phox were reduced. In macrophage cultures, in addition to a reduction in ROS release, nitric oxide and iNOS expression were down-regulated. The data suggest that one mechanism related to the effect of butyrate on atherosclerotic development is the reduction of oxidative stress in the lesion site. The reduction of oxidative stress related to NADPH oxidase and iNOS expression levels associated to butyrate supplementation attenuates endothelium dysfunction and macrophage migration and activation in the lesion site.


Subject(s)
Antioxidants/therapeutic use , Atherosclerosis/prevention & control , Butyric Acid/therapeutic use , Dietary Supplements , Endothelium, Vascular/metabolism , NADPH Oxidases/antagonists & inhibitors , Oxidative Stress , Animals , Atherosclerosis/immunology , Atherosclerosis/metabolism , Atherosclerosis/pathology , Biomarkers/blood , Biomarkers/metabolism , Cells, Cultured , Endothelium, Vascular/immunology , Endothelium, Vascular/pathology , Enzyme Repression , Human Umbilical Vein Endothelial Cells/cytology , Human Umbilical Vein Endothelial Cells/immunology , Human Umbilical Vein Endothelial Cells/metabolism , Humans , Lipoproteins, LDL/adverse effects , Macrophage Activation , Macrophages, Peritoneal/immunology , Macrophages, Peritoneal/metabolism , Macrophages, Peritoneal/pathology , Male , Mice, Knockout , NADPH Oxidases/metabolism , Nitric Oxide Synthase Type II/antagonists & inhibitors , Nitric Oxide Synthase Type II/metabolism , Reactive Oxygen Species/antagonists & inhibitors , Reactive Oxygen Species/metabolism
3.
PLoS One ; 10(10): e0141196, 2015.
Article in English | MEDLINE | ID: mdl-26513474

ABSTRACT

Leishmania is an intracellular parasite in vertebrate hosts, including man. During infection, amastigotes replicate inside macrophages and are transmitted to healthy cells, leading to amplification of the infection. Although transfer of amastigotes from infected to healthy cells is a crucial step that may shape the outcome of the infection, it is not fully understood. Here we compare L. amazonensis and L. guyanensis infection in C57BL/6 and BALB/c mice and investigate the fate of macrophages when infected with these species of Leishmania in vitro. As previously shown, infection of mice results in distinct outcomes: L. amazonensis causes a chronic infection in both strains of mice (although milder in C57BL/6), whereas L. guyanensis does not cause them disease. In vitro, infection is persistent in L. amazonensis-infected macrophages whereas L. guyanensis growth is controlled by host cells from both strains of mice. We demonstrate that, in vitro, L. amazonensis induces apoptosis of both C57BL/6 and BALB/c macrophages, characterized by PS exposure, DNA cleavage into nucleosomal size fragments, and consequent hypodiploidy. None of these signs were seen in macrophages infected with L. guyanensis, which seem to die through necrosis, as indicated by increased PI-, but not Annexin V-, positive cells. L. amazonensis-induced macrophage apoptosis was associated to activation of caspases-3, -8 and -9 in both strains of mice. Considering these two species of Leishmania and strains of mice, macrophage apoptosis, induced at the initial moments of infection, correlates with chronic infection, regardless of its severity. We present evidence suggestive that macrophages phagocytize L. amazonensis-infected cells, which has not been verified so far. The ingestion of apoptotic infected macrophages by healthy macrophages could be a way of amastigote spreading, leading to the establishment of infection.


Subject(s)
Leishmania/immunology , Macrophages/physiology , Macrophages/parasitology , Animals , Apoptosis , Caspase 8/metabolism , Caspase 9/metabolism , Cell Membrane Permeability , Cells, Cultured , DNA Fragmentation , Diploidy , Disease Models, Animal , Disease Progression , Leishmania guyanensis , Leishmaniasis/immunology , Leishmaniasis/parasitology , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL
4.
J Parasitol Res ; 2012: 203818, 2012.
Article in English | MEDLINE | ID: mdl-22570765

ABSTRACT

Cutaneous leishmaniasis affects millions of people around the world. Several species of Leishmania infect mouse strains, and murine models closely reproduce the cutaneous lesions caused by the parasite in humans. Mouse models have enabled studies on the pathogenesis and effector mechanisms of host resistance to infection. Here, we review the role of nitric oxide (NO), reactive oxygen species (ROS), and peroxynitrite (ONOO(-)) in the control of parasites by macrophages, which are both the host cells and the effector cells. We also discuss the role of neutrophil-derived oxygen and nitrogen reactive species during infection with Leishmania. We emphasize the role of these cells in the outcome of leishmaniasis early after infection, before the adaptive T(h)-cell immune response.

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