Leishmania amazonensis fails to induce the release of reactive oxygen intermediates by CBA macrophages (original) (raw)
Related papers
Macrophage killing of Leishmania amazonensis amastigotes requires both nitric oxide and superoxide
The American journal of tropical medicine and hygiene, 2007
The requirements for effective and efficient intracellular killing of Leishmania amazonensis by activated macrophages are unknown. Despite resistance to the arginase inhibitor LOHA by intracellular L. amazonensis amastigotes, enhanced replication did not account for the relative resistance of this parasite to macrophage activation. Herein we report that the presence of both superoxide and nitric oxide is necessary for efficient killing of L. amazonensis amastigotes within LPS/IFN-gamma-activated bone marrow-derived macrophages generated from C3H mice. Addition of an extracellular signal-regulated kinase (ERK) inhibitor to L. amazonensis-infected macrophages increased the ability of these activated macrophages to kill L. amazonensis amastigotes. This enhanced macrophage killing through addition of ERK inhibitor was abrogated by inhibition of superoxide or iNOS, whereas inhibiting superoxide had no effect on the killing of L. major. These results suggest that ERK activation may modula...
Role of superoxide dismutase in survival of Leishmania within the macrophage
Biochemical Journal, 2003
Intracellular parasitic protozoans of the genus Leishmania depend for their survival on the elaboration of enzymic and other mechanisms for evading toxic free-radical damage inflicted by their phagocytic macrophage host. One such mechanism may involve superoxide dismutase (SOD), which detoxifies reactive superoxide radicals produced by activated macrophages, but the role of this enzyme in parasite survival has not yet been demonstrated. We have cloned a SOD gene from L. tropica and generated SOD-deficient parasites by expressing the corresponding antisense RNA from an episomal vector. Such parasites have enhanced sensitivity to menadione and hydrogen peroxide in axenic culture, and a markedly reduced survival in mouse macrophages. These results indicate that SOD is a major determinant of intracellular survival of Leishmania.
Oxidative Responses of Human and Murine Macrophages During Phagocytosis ofLeishmania chagasi
The Journal of Immunology, 2001
Leishmania chagasi, the cause of South American visceral leishmaniasis, must survive antimicrobial responses of host macrophages to establish infection. Macrophage oxidative responses have been shown to diminish in the presence of intracellular leishmania. However, using electron spin resonance we demonstrated that murine and human macrophages produce O2− during phagocytosis of opsonized promastigotes. Addition of the O2− scavenger 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl to cultures resulted in increased infection, suggesting that O2− enhances macrophage leishmanicidal activity. The importance of NO· produced by inducible NO synthase (iNOS) in controlling murine leishmaniasis is established, but its role in human macrophages has been debated. We detected NO· in supernatants from murine, but not human, macrophages infected with L. chagasi. Nonetheless, the iNOS inhibitor NG-monomethyl-l-arginine inhibited IFN-γ-mediated intracellular killing by both murine and human macrophage...
Parasites & Vectors, 2016
Background: Reactive oxygen species (ROS) protect the host against a large number of pathogenic microorganisms. ROS have different effects on parasites of the genus Leishmania: some parasites are susceptible to their action, while others seem to be resistant. The role of ROS in L. amazonensis infection in vivo has not been addressed to date. Methods: In this study, C57BL/6 wild-type mice (WT) and mice genetically deficient in ROS production by phagocytes (gp91 phox−/−) were infected with metacyclic promastigotes of L. amazonensis to address the effect of ROS in parasite control. Inflammatory cytokines, parasite loads and myeloperoxidase (MPO) activity were evaluated. In parallel, in vitro infection of peritoneal macrophages was assessed to determine parasite killing, cytokine, NO and ROS production. Results: In vitro results show induction of ROS production by infected peritoneal macrophages, but no effect in parasite killing. Also, ROS do not seem to be important to parasite killing in vivo, but they control lesion sizes at early stages of infection. IFN-γ, TNF-α and IL-10 production did not differ among mouse strains. Myeloperoxidase assay showed augmented neutrophils influx 6 h and 72 h post-infection in gp91 phox−/− mice, indicating a larger inflammatory response in gp91 phox−/− even at early time points. At later time points, neutrophil numbers in lesions correlated with lesion size: larger lesions in gp91 phox−/− at earlier times of infection corresponded to larger neutrophil infiltrates, while larger lesions in WT mice at the later points of infection also displayed larger numbers of neutrophils. Conclusion: ROS do not seem to be important in L. amazonensis killing, but they regulate the inflammatory response probably by controlling neutrophils numbers in lesions.
Leishmania amazonensis and macrophage interactions: immune factors necessary to kill the parasite
List of Tables vi List of Figures vii CHAPTER 1 General Introduction V 2.4.7 Glutathione 3. Host immune response to Leishmania 3.1 CD4 + T cells and L. major infection 3.2 CD4 + T cells and L. amazonensis 3.3 B cells 4. General conclusion References CHAPTER 2 Macrophage killing of Leishmania amazonensis amastigotes requires both nitric oxide and superoxide Abstract Introduction Material and methods Results Discussion References CHAPTER 3 Leishmania major specific CD4 + T cells and B cells limit L. amazonensis amastigote survival within in vitro infected macrophages through IgG mediated superoxide production Abstract Introduction Material and methods Results Discussion References CHAPTER 4 Leishmania infection modulates the expression of Fey receptors Abstract CHAPTER 2 Macrophage killing of Leishmania amazonensis amastigotes requires both nitric oxide and superoxide
Journal of Investigative Dermatology, 2014
Cure of infections with Leishmania major is critically dependent on the ability of macrophages to induce the type 2 nitic oxide (NO) synthase (NOS2) that produces high levels of NO in the presence of ample oxygen. Therefore, we analyzed the oxygen levels found in leishmanial skin lesions and their effect on the NOS2-dependent leishmanicidal activity of macrophages (MF). When L. major skin lesions of self-healing C57BL/6 mice reached their maximum size, the infected tissue displayed low oxygen levels (pO 2 B21 Torr). MF activated under these oxygen tensions failed to produce sufficient amounts of NO to clear L. major. Nos2-deficient and hypoxic wildtype macrophages displayed a similar phenotype. Killing was restored when MF were reoxygenated or exposed to a NO donor. The resolution of the lesion in C57BL/6 mice was paralleled by an increase of lesional pO 2. When mice were kept under normobaric hypoxia, this caused a persistent suppression of the lesional pO 2 and a concurrent increase of the parasite load. In Nos2-deficient mice, there was no effect of atmospheric hypoxia. Low oxygen levels found at leishmanial skin lesions impaired the NOS2-dependent leishmanicidal activity of MF. Hence, tissue oxygenation represents an underestimated local milieu factor that participates in the persistence of Leishmania.
The Dangerous Liaisons in the Oxidative Stress Response to Leishmania Infection
Pathogens
Leishmania parasites preferentially invade macrophages, the professional phagocytic cells, at the site of infection. Macrophages play conflicting roles in Leishmania infection either by the destruction of internalized parasites or by providing a safe shelter for parasite replication. In response to invading pathogens, however, macrophages induce an oxidative burst as a mechanism of defense to promote pathogen removal and contribute to signaling pathways involving inflammation and the immune response. Thus, oxidative stress plays a dual role in infection whereby free radicals protect against invading pathogens but can also cause inflammation resulting in tissue damage. The induced oxidative stress in parasitic infections triggers the activation in the host of the antioxidant response to counteract the damaging oxidative burst. Consequently, macrophages are crucial for disease progression or control. The ultimate outcome depends on dangerous liaisons between the infecting Leishmania s...
Frontiers in Cellular and Infection Microbiology, 2021
Macrophage–Leishmania interactions are central to parasite growth and disease outcome. Macrophages have developed various strategies to fight invaders, including oxidative burst. While some microorganisms seem to survive and even thrive in an oxidative environment, others are susceptible and get killed. To counter oxidative stress, macrophages switch the expressions of cytoprotective and detoxifying enzymes, which are downstream targets of the nuclear factor erythroid 2-related factor 2 (Nrf2), to enhance cell survival. We have explored the transcription of NRF2 and of its target genes and compared the effect of the parasite on their transcription in bone marrow-derived macrophages (BMdMs) from Leishmania-resistant and Leishmania-susceptible mice. While heme oxygenase 1 (HO-1) transcription is independent of the genetic background, the transcription of glutathione reductase (Gsr) and of cysteine/glutamate exchange transporter (Slc7a11), involved in glutathione accumulation, was diff...
Periodate-oxidized ATP modulates macrophage functions during infection with Leishmania amazonensis
Cytometry Part A, 2014
Previously, we showed that treating macrophages with ATP impairs the intracellular growth of Leishmania amazonensis, and that the P2X7 purinergic receptor is overexpressed during leishmaniasis. In the present study, we directly evaluated the effect of periodate-oxidized ATP (oATP) on parasite control in Leishmania-infected macrophages. We found that oATP impaired the attachment/entrance of L. amazonensis promastigotes to C57BL/6 mouse macrophages in a P2X7 receptor-independent manner, as macrophages from P2X7 2/2 mice were similarly affected. Although oATP directly inhibited the growth of axenic promastigotes in culture, promoted rapid ultrastructural alterations, and impaired Leishmania internalization by macrophages, it did not affect intracellular parasite multiplication. Upon infection, phagosomal acidification was diminished in oATP-treated macrophages, accompanied by reduced endosomal proteolysis. Likewise, MHC class II molecules expression and ectoATPase activity was decreased by oATP added to macrophages at the time of parasite infection. These inhibitory effects were not due to a cytotoxic effect, as no additional release of lactate dehydrogenase was detected in culture supernatants. Moreover, the capacity of macrophages to produce nitric oxide and reactive oxygen species was not affected by the presence of oATP during infection. We conclude that oATP directly affects extracellular parasite integrity and macrophage functioning. V C 2014 International Society for Advancement of Cytometry Key terms oxidized adenosine triphosphate; Leishmania amazonensis; acidification; phagosomal maturation CUTANEOUS leishmaniasis affects $20 million people annually worldwide (1). The disease is caused by protozoan parasites of the genus Leishmania, such as L. braziliensis and L. amazonensis in the New World and Leishmania major in Old World. The disease shows different clinical manifestations depending on the parasite species and host immunity (2). The typical cutaneous lesion is localized, crater-like and selfhealing but may evolve into morbid diffuse or mucosal forms. During a blood meal, a sand fly vector inoculates the infective form, called the promastigote, into the skin of the mammalian host, where it is taken up by phagocytic cells and transforms into an amastigote (3). After being phagocytosed, the parasites are contained in intracellular vesicles called parasitophorous vacuoles (PV) where they subvert the microbicidal mechanisms of the host cell and obtain all the necessary nutrients for their survival. These parasites modulate different pathways in macrophages, neutrophils and dendritic cells and inhibit MAPK p38 and iNOS (4,5). Some species are also capable of impairing apoptosis, reactive oxygen species (ROS) production and nitric oxide (NO) synthesis, all of which are crucial to the control of the intracellular infec