Leishmania donovani lacking the Golgi GDP-Man transporter LPG2 exhibit attenuated virulence in mammalian hosts

Gaur, Upasna; Showalter, Melissa; Hickerson, Suzanne M.; Dalvi, Rahul P.; Turco, Salvatore J.; Wilson, Mary E.; Beverley, Stephen M.

doi:10.1016/j.exppara.2009.03.014

Cited by 54 publications

(48 citation statements)

References 48 publications

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“…4A). This was not unexpected, since a lack of robust complementation has been frequently observed in transgenic Leishmania (33)(34)(35). Nine weeks after infection, the mice were sacrificed, and footpad tissue was collected for parasite quantification by limiting dilution.…”

Section: Resultsmentioning

confidence: 99%

Heme Uptake Mediated by LHR1 Is Essential for Leishmania amazonensis Virulence

et al. 2013

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The protozoan parasite Leishmania amazonensis is a heme auxotroph and must acquire this essential factor from the environment. Previous studies showed that L. amazonensis incorporates heme through the transmembrane protein LHR1 (Leishmania Heme Response 1). LHR1-null promastigotes were not viable, suggesting that the transporter is essential for survival. Here, we compared the growth, differentiation, and infectivity for macrophages and mice of wild-type, LHR1-single-knockout (LHR1/ ⌬lhr1), and LHR1-complemented (LHR1/⌬lhr1 plus LHR1) L. amazonensis strains. LHR1/⌬lhr1 promastigotes replicated poorly in heme-deficient media and had lower intracellular heme content than wild-type parasites. LHR1/⌬lhr1 promastigotes were also less effective in reducing ferric iron to ferrous iron, a reaction mediated by the heme-containing parasite enzyme LFR1 (Leishmania Ferric Reductase 1). LHR1/⌬lhr1 parasites differentiated normally into aflagellated forms expressing amastigote-specific markers but were not able to replicate intracellularly after infecting macrophages. Importantly, the intracellular growth of LHR1/⌬lhr1 amastigotes was fully restored when macrophages were allowed to phagocytose red blood cells prior to infection. LHR1/⌬lhr1 parasites were also severely defective in the development of cutaneous lesions in mice. All phenotypes observed in LHR1/⌬lhr1 L. amazonensis were rescued by expression of episomal LHR1. Our results reveal the importance of efficient heme uptake for L. amazonensis replication and vertebrate host infectivity, reinforcing the potential usefulness of LHR1 as a target for new antileishmanial drugs.

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Section: Resultsmentioning

confidence: 99%

Heme Uptake Mediated by LHR1 Is Essential for Leishmania amazonensis Virulence

et al. 2013

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“…Although we did not examine directly the expression of LPG by WT exosomes, several lines of evidence suggest that LPG expression on exosomes is likely: 1) we found that leishmania exosomes contain a large number of known leishmania surface proteins, both transmembrane and, like LPG, GPIlinked (13); 2) we also found that leishmania exosomes contain LPG2 (13), which is required for cell surface expression of LPG by L. donovani (31); and 3) leishmania exosomes appeared to be predominantly immunosuppressive, a known property of LPG (29,31).…”

Section: Influence Of Exosomes On Acquired Immune Responsesmentioning

confidence: 99%

“…2/2 L. donovani show reduced infection rates both in vitro in macrophages and in vivo in murine models of infection (31), suggesting that surface phosphoglycans are important for virulence. HSP100 2/2 L. donovani also showed reduced virulence in vitro in macrophages, and HSP100 2/2 L. major was avirulent in vivo while showing no reduced viability as axenic culture forms (16,19).…”

Section: Immunomodulation By Leishmania Exosomes Is Influenced By Vesmentioning

confidence: 99%

Leishmania Exosomes Modulate Innate and Adaptive Immune Responses through Effects on Monocytes and Dendritic Cells

Silverman

Clos

Horáková

et al. 2010

The Journal of Immunology

275

343

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We investigated the properties of leishmania exosomes with respect to influencing innate and adaptive immune responses. Exosomes from Leishmania donovani modulated human monocyte cytokine responses to IFN-γ in a bimodal fashion by promoting IL-10 production and inhibiting that of TNF-α. Moreover, these vesicles were inhibitory with respect to cytokine responses (IL-12p70, TNF-α, and IL-10) by human monocyte-derived dendritic cells. Exosomes from wild-type (WT) L. donovani failed to prime monocyte-derived dendritic cells to drive the differentiation of naive CD4 T cells into IFN-γ–producing Th1 cells. In contrast, vesicles from heat shock protein (HSP)100−/− L. donovani showed a gain-of-function and proinflammatory phenotype and promoted the differentiation of naive CD4 lymphocytes into Th1 cells. Proteomic analysis showed that exosomes from WT and HSP100−/− leishmania had distinct protein cargo, suggesting that packaging of proteins into exosomes is dependent in part on HSP100. Treatment of C57BL/6 mice with WT L. donovani exosomes prior to challenge with WT organisms exacerbated infection and promoted IL-10 production in the spleen. In contrast, HSP100−/− exosomes promoted spleen cell production of IFN-γ and did not adversely affect hepatic parasite burdens. Furthermore, the proparasitic properties of WT exosomes were not species specific because BALB/c mice exposed to Leishmania major exosomes showed increased Th2 polarization and exacerbation of disease in response to infection with L. major. These findings demonstrate that leishmania exosomes are predominantly immunosuppressive. Moreover, to our knowledge, this is the first evidence to suggest that changes in the protein cargo of exosomes may influence the impact of these vesicles on myeloid cell function.

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“…Analysis for mean fluorescence intensity was done using CellQuest Pro software (BD Biosciences, CA). A total of 20,000 events from each sample were acquired to ensure adequate data, and the histograms and images are representative of three independent experiments (32,33).…”

Section: Synthesis Of Ag Nps and Tiomentioning

confidence: 99%

Green Synthesis of Silver and Titanium Dioxide Nanoparticles Using Euphorbia prostrata Extract Shows Shift from Apoptosis to G ₀ /G ₁ Arrest followed by Necrotic Cell Death in Leishmania donovani

Zahir¹,

Chauhan

Bagavan³

et al. 2015

Antimicrob Agents Chemother

157

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The aim of the present study was to synthesize silver (Ag) and titanium dioxide (TiO 2 ) nanoparticles (NPs) using green synthesis from aqueous leaf extract of Euphorbia prostrata as antileishmanial agents and to explore the underlying molecular mechanism of induced cell death. In vitro antileishmanial activity of synthesized NPs was tested against promastigotes of Leishmania donovani by alamarBlue and propidium iodide uptake assays. Antileishmanial activity of synthesized NPs on intracellular amastigotes was assessed by Giemsa staining. The leishmanicidal effect of synthesized Ag NPs was further confirmed by DNA fragmentation assay and by cell cycle progression and transmission electron microscopy (TEM) of the treated parasites. TEM analysis of the synthesized Ag NPs showed a spherical shape with an average size of 12.82 ؎ 2.50 nm, and in comparison to synthesized TiO 2 NPs, synthesized Ag NPs were found to be most active against Leishmania parasites after 24 h exposure, with 50% inhibitory concentrations (IC 50 ) of 14.94 g/ml and 3.89 g/ml in promastigotes and intracellular amastigotes, respectively. A significant increase in G 0 /G 1 phase of the cell cycle with a subsequent decrease in S (synthesis) and G 2 /M phases compared to controls was observed. The growth-inhibitory effect of synthesized Ag NPs was attributed to increased length of S phase. A decreased reactive oxygen species level was also observed, which could be responsible for the caspase-independent shift from apoptosis (G 0 /G 1 arrest) to massive necrosis. High-molecular-weight DNA fragmentation as a positive consequence of necrotic cell death was also visualized. We also report that the unique trypanothione/trypanothione reductase (TR) system of Leishmania cells was significantly inhibited by synthesized Ag NPs. The green-synthesized Ag NPs may provide promising leads for the development of costeffective and safer alternative treatment against visceral leishmaniasis.

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Leishmania donovani lacking the Golgi GDP-Man transporter LPG2 exhibit attenuated virulence in mammalian hosts

Cited by 54 publications

References 48 publications

Heme Uptake Mediated by LHR1 Is Essential for Leishmania amazonensis Virulence

Heme Uptake Mediated by LHR1 Is Essential for Leishmania amazonensis Virulence

Leishmania Exosomes Modulate Innate and Adaptive Immune Responses through Effects on Monocytes and Dendritic Cells

Green Synthesis of Silver and Titanium Dioxide Nanoparticles Using Euphorbia prostrata Extract Shows Shift from Apoptosis to G ₀ /G ₁ Arrest followed by Necrotic Cell Death in Leishmania donovani

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Leishmania donovani lacking the Golgi GDP-Man transporter LPG2 exhibit attenuated virulence in mammalian hosts

Cited by 54 publications

References 48 publications

Heme Uptake Mediated by LHR1 Is Essential for Leishmania amazonensis Virulence

Heme Uptake Mediated by LHR1 Is Essential for Leishmania amazonensis Virulence

Leishmania Exosomes Modulate Innate and Adaptive Immune Responses through Effects on Monocytes and Dendritic Cells

Green Synthesis of Silver and Titanium Dioxide Nanoparticles Using Euphorbia prostrata Extract Shows Shift from Apoptosis to G 0 /G 1 Arrest followed by Necrotic Cell Death in Leishmania donovani

Contact Info

Product

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Green Synthesis of Silver and Titanium Dioxide Nanoparticles Using Euphorbia prostrata Extract Shows Shift from Apoptosis to G ₀ /G ₁ Arrest followed by Necrotic Cell Death in Leishmania donovani