Transcriptomic and Translatomic Responses of Leishmania major to Heat Shock Stress
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ABSTRACT:
ORGANISM(S): Leishmania major
PROVIDER: GSE276368 | GEO | 2025/12/30
REPOSITORIES: GEO
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Project description:Protozoa of the genus Leishmania are the causative agents of leishmaniasis in humans. These parasites cycle between promastigotes in the sand fly mid-gut and amastigotes in phagolysosome of mammalian macrophages. During infection, host up-regulate nitric oxide synthase and parasite induce host arginase expression, both of which use arginine as a substrate. These elevated activities deplete macrophage arginine pools, a situation that invading Leishmania must overcome since it is an essential amino acid. Leishmania donovani imports exogenous arginine via a mono-specific amino acid transporter (AAP3) and utilizes it primarily through the polyamine pathway to provide precursors for trypanothione biosynthesis. Here we report the discovery of a pathway whereby promastigote and amastigote forms of the Leishmania sense the lack of environmental arginine and respond with rapid up-regulation in AAP3 expression and activity, as well as several other transporters. Significantly, this arginine deprivation response is also activated in parasites during macrophage infection. Phosphoproteomic analyses of L. donovani promastigotes have implicated a Mitogen-Activated Protein Kinase 2 (MPK2)-mediated signaling cascade in this response and L. mexicana mutants lacking MPK2 are unable to respond to arginine deprivation. In this study, we established that Leishmania cells sense the absence of arginine in their environment; both in culture (axenic promastigotes and amastigotes) and in macrophages during infection (amastigotes). This study describes the first amino acid deprivation sensing mechanism and the pathway that transduce this response, and reveals a novel host-pathogen metabolic interplay. Total RNA from Ten Leishmania donovani samples were analyzed using RNA-Seq. Cells from two life stages (promastigotes and amastigotes) were grown in axenic culture in the presence and absense of arginine. For each condition two biological replicates were grown and analyzed. In addition two macrophage grown amastigotes were analyzed.
2016-08-01 | E-GEOD-71572 | biostudies-arrayexpress
Project description:Protozoa of the genus Leishmania are the causative agents of leishmaniasis in humans. These parasites cycle between promastigotes in the sand fly mid-gut and amastigotes in phagolysosome of mammalian macrophages. During infection, host up-regulate nitric oxide synthase and parasite induce host arginase expression, both of which use arginine as a substrate. These elevated activities deplete macrophage arginine pools, a situation that invading Leishmania must overcome since it is an essential amino acid. Leishmania donovani imports exogenous arginine via a mono-specific amino acid transporter (AAP3) and utilizes it primarily through the polyamine pathway to provide precursors for trypanothione biosynthesis. Here we report the discovery of a pathway whereby promastigote and amastigote forms of the Leishmania sense the lack of environmental arginine and respond with rapid up-regulation in AAP3 expression and activity, as well as several other transporters. Significantly, this arginine deprivation response is also activated in parasites during macrophage infection. Phosphoproteomic analyses of L. donovani promastigotes have implicated a Mitogen-Activated Protein Kinase 2 (MPK2)-mediated signaling cascade in this response and L. mexicana mutants lacking MPK2 are unable to respond to arginine deprivation. In this study, we established that Leishmania cells sense the absence of arginine in their environment; both in culture (axenic promastigotes and amastigotes) and in macrophages during infection (amastigotes). This study describes the first amino acid deprivation sensing mechanism and the pathway that transduce this response, and reveals a novel host-pathogen metabolic interplay.
2016-08-01 | GSE71572 | GEO
Project description:Leishmania (L) are intracellular protozoan parasites which are able to survive and replicate within the harsh and potentially hostile phago-lysosomal environment of mammalian mononuclear phagocytes. A complex interplay then takes place between the macrophage (MM-NM-&) striving to eliminate the pathogen and the parasite struggling for its own survival. To investigate, at the transcriptional level, this host-parasite conflict in the context of monocyte-derived human MM-NM-&s (MDM) infection by L. major metacyclic promastigotes, the quantitative technique of serial analysis of gene expression (SAGE) was used. After extracting mRNA from resting human MM-NM-&s, Leishmania-infected human MM-NM-&s and L. major parasites, three SAGE libraries were constructed and sequenced generating up to 28,173; 57,514 and 33,906 tags respectively (corresponding to 12,946; 23,442 and 9,530 unique tags). Using computational data analysis and direct comparison to 394,059 publicly available experimental human tags, the parasite and the host cell transcriptomes were then simultaneously characterized from the mixed cellular extract, allowing to confidently discriminate host from parasite transcripts. This procedure led us to reliably assign 3,814 tags to MM-NM-&sM-bM-^@M-^Y and 3,666 tags to L. major parasitesM-bM-^@M-^Y transcripts. We focused on those, showing significant changes in their expression that are likely to be relevant to the pathogenesis of parasite infection: (i) human MM-NM-&s genes, belonging to key immune response proteins (i.e. IFNM-NM-3 pathway, S100 and chemokine families) and (ii) a group of Leishmania genes showing a preferential expression at the intra-cellular developing stage of the parasite. Dual SAGE transcriptome analysis provided a useful, powerful and accurate approach to discriminate between genes of human or parasitic origin in Leishmania-infected human MM-NM-&s. The findings presented in this work suggest that the Leishmania parasite is modulating key transcripts in the human MM-NM-&s that may be beneficial for its establishment and survival and provided an overview of gene expression at two developmental stages of the parasite, namely metacyclic promastigotes and intracellular amastigotes, indicating a broad difference between their transcriptomic profiles. Finally, our reported set of expressed genes could deserve future rounds of data mining and gene annotation. Keywords: Leishmania major, Human macrophages, in vitro, infection, transcriptome, SAGE Human monocyte derived macrophages (MDM) from four healthy donors were infected in vitro for 24 hours with metacyclic Leishmania major parasites (ratio 1:5) and the pool was used to construct SAGE library. Non infected MDM from the same donors and from metacyclic Leishmania major parasites were used to construct the two controls' SAGE libraries.
2008-05-21 | E-GEOD-10442 | biostudies-arrayexpress
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.
2012-12-15 | GSE41641 | GEO
Project description:Leishmania (L) are intracellular protozoan parasites which are able to survive and replicate within the harsh and potentially hostile phago-lysosomal environment of mammalian mononuclear phagocytes. A complex interplay then takes place between the macrophage (MΦ) striving to eliminate the pathogen and the parasite struggling for its own survival. To investigate, at the transcriptional level, this host-parasite conflict in the context of monocyte-derived human MΦs (MDM) infection by L. major metacyclic promastigotes, the quantitative technique of serial analysis of gene expression (SAGE) was used. After extracting mRNA from resting human MΦs, Leishmania-infected human MΦs and L. major parasites, three SAGE libraries were constructed and sequenced generating up to 28,173; 57,514 and 33,906 tags respectively (corresponding to 12,946; 23,442 and 9,530 unique tags). Using computational data analysis and direct comparison to 394,059 publicly available experimental human tags, the parasite and the host cell transcriptomes were then simultaneously characterized from the mixed cellular extract, allowing to confidently discriminate host from parasite transcripts. This procedure led us to reliably assign 3,814 tags to MΦs’ and 3,666 tags to L. major parasites’ transcripts. We focused on those, showing significant changes in their expression that are likely to be relevant to the pathogenesis of parasite infection: (i) human MΦs genes, belonging to key immune response proteins (i.e. IFNγ pathway, S100 and chemokine families) and (ii) a group of Leishmania genes showing a preferential expression at the intra-cellular developing stage of the parasite. Dual SAGE transcriptome analysis provided a useful, powerful and accurate approach to discriminate between genes of human or parasitic origin in Leishmania-infected human MΦs. The findings presented in this work suggest that the Leishmania parasite is modulating key transcripts in the human MΦs that may be beneficial for its establishment and survival and provided an overview of gene expression at two developmental stages of the parasite, namely metacyclic promastigotes and intracellular amastigotes, indicating a broad difference between their transcriptomic profiles. Finally, our reported set of expressed genes could deserve future rounds of data mining and gene annotation. Keywords: Leishmania major, Human macrophages, in vitro, infection, transcriptome, SAGE
2008-05-22 | GSE10442 | GEO
Project description:The ability of Leishmania to survive in their insect or mammalian host is dependent upon an ability to sense and adapt to changes in the microenvironment. However, little is known about the molecular mechanisms underlying the parasite response to environmental changes, such as nutrient availability. To elucidate nutrient stress response pathways in Leishmania donovani, we have used purine starvation as the paradigm. The salvage of purines from the host milieu is obligatory for parasite replication; nevertheless, purine-starved parasites can persist in culture without supplementary purine for over 3 months, indicating that the response to purine starvation is robust and engenders parasite survival under conditions of extreme scarcity. To understand metabolic reprogramming during purine starvation we have employed global approaches. Whole proteome comparisons between purine-starved and purine-replete parasites over a 6-48 h span have revealed a temporal and coordinated response to purine starvation. Purine transporters and enzymes involved in acquisition at the cell surface are upregulated within a few hours of purine removal from the media, while other key purine salvage components are upregulated later in the time-course and more modestly. After 48 h, the proteome of purine-starved parasites is extensively remodeled and adaptations to purine stress appear tailored to deal with both purine deprivation and general stress. To probe the molecular mechanisms affecting proteome remodeling in response to purine starvation, comparative RNA-seq analyses, qRT-PCR, and luciferase reporter assays were performed on purine-starved versus purine-replete parasites. While the regulation of a minority of proteins tracked with changes at the mRNA level, for many regulated proteins it appears that proteome remodeling during purine stress occurs primarily via translational and post-translational mechanisms. One mRNA sample from each of Purine-Starved and Purine-Replete cells were analyzed using SL RNA-Seq methodology
2014-02-01 | E-GEOD-48394 | biostudies-arrayexpress
Project description:Drug resistance is a major public health challenge in Leishmaniasis chemotherapy, particularly in the case of emerging Leishmania/HIV-1 co-infections. Recently, we have delineated the mechanism of cell death induced by the HIV-1 protease inhibitor, Nelfinavir, in the Leishmania parasite. In order to investigate the underlying molecular mechanism involved in Nelfinavir resistance, in vitro Nelfinavir resistant amastigotes were developed by direct drug pressure in culture. RNA expression profiling analyses of closely related Leishmania species were used as a screening tool to compare Nelfinavir-resistant and -sensitive parasites in order to identify candidate genes involved in drug resistance, and several genes were found to be differentially expressed. Comparative gene hybridization (CGH) analyses of Nelfinavir-resistant and -sensitive Leishmania using whole-genome 60-mer oligonucleotide microarrays were also carried out. RNA expression profiles and the CGH of Nelfinavir resistant vs sensitive Leishmania amastigotes suggest that parasites regulate mRNA levels either by modulating gene copy numbers through chromosome aneuploidy, or gene deletion/duplication by homologous recombination. Interestingly, supernumerary chromosomes 6 and 11 in the resistant parasites lead to upregulation of the ABC class of transporters, which are involved in vesicular trafficking. Transporter assays using radiolabeled Nelfinavir suggest that the drug accumulates in greater amounts in the resistant parasites and in a time dependent manner. Furthermore, high-resolution electron microscopy showed an increased number of vacuoles in Nelfinavir-resistant parasites. Together these results suggest that Nelfinavir is rapidly and dramatically sequestered in these intracellular vesicles.
2013-06-27 | GSE42195 | GEO
Project description:Drug resistance is a major public health challenge in Leishmaniasis chemotherapy, particularly in the case of emerging Leishmania/HIV-1 co-infections. Recently, we have delineated the mechanism of cell death induced by the HIV-1 protease inhibitor, Nelfinavir, in the Leishmania parasite. In order to investigate the underlying molecular mechanism involved in Nelfinavir resistance, in vitro Nelfinavir resistant amastigotes were developed by direct drug pressure in culture. RNA expression profiling analyses of closely related Leishmania species were used as a screening tool to compare Nelfinavir-resistant and -sensitive parasites in order to identify candidate genes involved in drug resistance, and several genes were found to be differentially expressed. Comparative gene hybridization (CGH) analyses of Nelfinavir-resistant and -sensitive Leishmania using whole-genome 60-mer oligonucleotide microarrays were also carried out. RNA expression profiles and the CGH of Nelfinavir resistant vs sensitive Leishmania amastigotes suggest that parasites regulate mRNA levels either by modulating gene copy numbers through chromosome aneuploidy, or gene deletion/duplication by homologous recombination. Interestingly, supernumerary chromosomes 6 and 11 in the resistant parasites lead to upregulation of the ABC class of transporters, which are involved in vesicular trafficking. Transporter assays using radiolabeled Nelfinavir suggest that the drug accumulates in greater amounts in the resistant parasites and in a time dependent manner. Furthermore, high-resolution electron microscopy showed an increased number of vacuoles in Nelfinavir-resistant parasites. Together these results suggest that Nelfinavir is rapidly and dramatically sequestered in these intracellular vesicles.
2013-06-27 | GSE42196 | GEO
Project description:In mammals, resident dermal macrophages (MΦs) are subverted by Leishmania (L.) amazonensis amastigotes as host cells permissive for parasite multiplication. These Leishmania are living within a communal parasitophorous vacuole (PV) and are expected to trigger unique MΦ transcriptional signatures. We performed a transcription profiling of mouse MΦs harboring amastigotes to get insights into their reprogramming as host cells for parasite multiplication. BALB/c mouse bone marrow-derived MΦs were either loaded or not with four amastigotes on average. Twenty four hours later, when amastigotes multiply, total RNA from MΦ cultures was prepared, amplified and hybridized onto Affymetrix Mouse430_2 GeneChips®. The outcome recorded a total of 1,248 probe-sets showing significant differential expression. Comparable fold-change values for a handful of genes were obtained between Affymetrix technology and the more sensitive RTqPCR method. Ingenuity Pathway Analysis software® pinpointed the up-regulation of the sterol biosynthesis pathway (P-value = 1.31e-02) involving several genes (1.95 to 4.30 fold-change values), and the modulation of various genes involved in polyamine synthesis and in pro/counter-inflammatory signaling. Our findings suggest that amastigotes exploit the MΦ lipid and polyamine pathways to multiply efficiently, and induce a counter-inflammatory environment to expand their dermis niche.
2009-01-01 | GSE11497 | GEO
Project description:Monocyte derived dendritic cells (MDDC) were infected with Leishmania major or Leishmania donovani parasites and collected at 4, 8, and 24 hours post-infection to analyze the differential effects those parasite species have on human host cell gene expression over time. Monocyte derived dendritic cells (MDDC) were generated from blood buffy coats collected from five anonymous healthy human donors and infected 10:1 (parasite to host cell) with Leishmania major Friedlin V1 strain or Leishmania donovani 1S strain parasites, where after 4, 8, or 24 hours total RNA was harvested from cells, cDNA generated, and hybridized to human gene transcipt expression arrays to assess differential host cell gene transcriptional expression differences relative to uninfected cells.
2015-01-02 | E-GEOD-64610 | biostudies-arrayexpress