Project description:During its life cycle Leishmania undergoes extreme environmental changes, alternating between insect vectors and vertebrate hosts. In mammals the parasites replicate within parasitophorous vacuoles of macrophages, compartments that contain low concentrations of iron. Here we show that stimulation of iron transport, which is induced in Leishmania amazonensis by an iron-poor environment, triggers the differentiation of avirulent promastigotes into virulent amastigotes. Iron depletion from the culture medium triggered expression of the LIT1 ferrous iron transporter, growth arrest, and differentiation of wild type promastigotes into infective amastigotes. In contrast, LIT1 null promastigotes showed continued exponential growth in iron-poor media, followed by massive cell death. Iron depletion from the medium and LIT1 upregulation increased iron superoxide dismutase activity (FeSOD) in wild type, but not in LIT1 null parasites. Notably, the superoxide-generating drug menadione or H2O2 were sufficient to trigger differentiation of wild type promastigotes into fully infective amastigotes. On the other hand, LIT1 null promastigotes accumulated superoxide radical and initiated amastigote differentiation after exposure to H2O2, but not to menadione. Our results reveal a novel role for FeSOD activity and reactive oxygen species (ROS) in orchestrating the differentiation of Leishmania infective stages, in a process regulated by iron availability.
Project description:During its life cycle Leishmania undergoes extreme environmental changes, alternating between insect vectors and vertebrate hosts. In mammals the parasites replicate within parasitophorous vacuoles of macrophages, compartments that contain low concentrations of iron. Here we show that stimulation of iron transport, which is induced in Leishmania amazonensis by an iron-poor environment, triggers the differentiation of avirulent promastigotes into virulent amastigotes. Iron depletion from the culture medium triggered expression of the LIT1 ferrous iron transporter, growth arrest, and differentiation of wild type promastigotes into infective amastigotes. In contrast, LIT1 null promastigotes showed continued exponential growth in iron-poor media, followed by massive cell death. Iron depletion from the medium and LIT1 upregulation increased iron superoxide dismutase activity (FeSOD) in wild type, but not in LIT1 null parasites. Notably, the superoxide-generating drug menadione or H2O2 were sufficient to trigger differentiation of wild type promastigotes into fully infective amastigotes. On the other hand, LIT1 null promastigotes accumulated superoxide radical and initiated amastigote differentiation after exposure to H2O2, but not to menadione. Our results reveal a novel role for FeSOD activity and reactive oxygen species (ROS) in orchestrating the differentiation of Leishmania infective stages, in a process regulated by iron availability. Four samples were obtained in total from wild-type L. amazonensis promastigotes grown for 24 hours in culture. Two of these samples derived from medium with iron and two from mediam without iron.These two samples derived from each culture served as biological replicates.
Project description:In this study we report the complete repertoire of 2'-O-methylation sites present in the rRNA of Leishmania amazonensis rRNAs and a subset of small RNAs using RibOxi-seq.
Project description:Autophagy generally participates in innate immunity by elimination of intracellular pathogens. However, many of them developed successful strategies to counteract their autolysosomal digestion and lastly to exploit this catabolic cellular process. Protozoan parasites of the genus Leishmania are the causative agent of leishmaniasis, one of the 13 most important tropical diseases. Leishmania persists as endo-parasite in host macrophages, where it uses multiple strategies to manipulate the microbicidal host cell functions and to escape from the host immune system. Understanding how Leishmania interacts with host macrophages during uptake, differentiation, intracellular replication, and release might be the key to develop new drugs in target-directed approaches to treat patient with leishmaniasis. Here, we generated expression profiles from bone marrow-derived macrophages (BMDM) at 1h and 24h post infection (p.i.) with Leishmania major and respective controls.
Project description:Protozoan parasites of the genus Leishmania are the causative agent of leishmaniasis, one of the 13 most important tropical diseases. Leishmania persists as endo-parasite in host macrophages, where it uses multiple strategies to manipulate the microbicidal host cell functions and to escape from the host immune system. Understanding how Leishmania interacts with host macrophages during uptake, differentiation, intracellular replication, and release might be the key to develop new drugs in target-directed approaches to treat patient with leishmaniasis. Short non-coding RNAs are known to regulate the expression of protein-coding genes at post-transcriptional level. Characterization of these processes during Leishmania infection provides deeper insight in the interaction between host and parasites. Here, we generated miRNA expression profiles from bone marrow-derived macrophages (BMDM) at 4h and 24h post infection (p.i.) with Leishmania major and respective controls.
Project description:Protozoan parasites of the genus Leishmania are causative agents of leishmaniasis, a wide range of diseases affecting 12 million people worldwide. The species L. (L.) infantum and L. (L.) amazonensis are causative agents of visceral and cutaneous leishmaniasis, respectively. Most proteome analyses of Leishmania have been carried out on whole-cell extracts. However, this approach tends to underrepresent membrane-associated proteins because of their high hydrophobicity and low solubility. Due to the great importance of membrane-associated proteins in biological processes, including host–parasite interactions, virulence and invasiveness, this study applied label-free shotgun proteomics to characterize and evaluate abundance levels of plasma membrane sub-proteome of promastigotes life-stage. The total number of proteins identified in L. (L.) infantum and L. (L.) amazonensis was 2033 and 2243, respectively. Both species shared 1908 of these quantified proteins. After cell localization prediction of all identified proteins, 394 proteins were described as plasma membrane-associated proteins and their majority (320 proteins) was presented in both species. Considering only exclusive proteins, 18 proteins were detected only in L. (L.) infantum and 56 proteins in L. (L.) amazonensis. We used two criteria to define “regulated” proteins; i) proteins with p-value < 0.05 after One-Way ANOVA analysis (quantitative analysis) and proteins detected only in L. (L.) infantum or L. (L.) amazonensis (qualitative analysis).