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: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.
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 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.
Project description:Autophagy has been implicated as a host defense mechanism against intracellular pathogens. However, certain intracellular pathogens such as Leishmania can manipulate the host’s autophagy to promote their survival. Recently, our findings regarding the regulation of autophagy by Leishmania donovani indicate that this pathogen induces non-classical autophagy in infected macrophages, independent of mammalian target of rapamycin complex 1 regulation. This occurs in the background of enhanced mTOR activity, which suggests the fine-tuning of autophagy to optimally promote parasite survival and may involve the sequestration or modulation of specific autophagosome-associated proteins. To investigate how Leishmania potentially manipulates the composition of host-cell autophagosomes, we undertook a quantitative proteomic study of the human monocytic cell line THP-1 following infection with L. donovani. We used stable isotope labeling by amino acid in cell culture and liquid chromatography-tandem mass spectrometry to compare expression profiles between autophagosomes isolated from THP-1 cells infected with L. donovani or treated with known autophagy inducers. Select proteomics results were validated by immunoblotting. In this study, we showed that L. donovani modulates the composition of macrophage autophagosomes during infection when compared to autophagosomes induced by either rapamycin (selective autophagy) or starvation (non-selective autophagy). Among 1787 proteins detected in Leishmania-induced autophagosomes, 146 were significantly modulated compared to the proteome of rapamycin-induced autophagosomes while 57 were significantly modulated compared to starvation-induced autophagosomes. Strikingly, 23 Leishmania proteins were also detected in the proteome of Leishmania-induced autophagosomes. Together, our data provide the first comprehensive insight into the proteome dynamics of host autophagosomes in response to Leishmania infection and demonstrate the complex relations between the host and pathogen at the molecular level.
Project description:Several intracellular pathogens target the host miRNA to modulate the expression of host proteins for their successful infection and survival. For example, S. typhimurium (Schulte et al., 2011) and Mycobacterium tuberculosis (Kumar et al., 2015) downregulate miRNAs of let-7 family to modulate immune response in host; H. pylori infection induces the expression of miR-155 to inhibit the release of IL-8 (Xiao et al., 2009); L. monocytogens triggers the expression of anti- inflammatory cytokine IFN-β by downregulation of miR-145 (Izar et al., 2012). Similarly, Leishmania infection also modulates the expression of various miRNA in macrophages (Lemaire et al., 2013). Consequently, it has been shown that L. donovani infection downregulates miR-122 expression which lowers serum cholesterol to facilitate infection (Ghosh et al., 2013). Whereas, Leishmania significantly enhances the miR30A- 3p expression and modulates autophagic pathway in macrophages (Singh et al., 2016). To understand how Leishmania modulate the expression of various genes in infected macrophages, we have compared the miRNA profile of uninfected and infected macrophages.
Project description:Infection with antimony resistant (SbR) but not with sentitive (SbS) Leishmania donovani (LD) gives rise to aggressive pathology in mammalian hosts, the cause of which is far from clear. Some intracellular pathogens exploit autophagy for their own benefit. Here we show that induction of autophagy in normal macrophages (MF) by pharmacological mediators prior to infection with SbRLD (SbRLD-MF) enhanced their growth as compared to untreated MF, unlike SbSLD-MF. Autophagy was evident in SbRLD-MF from electron microscopical studies showing double membrane-bound compartment around amastigote. In SbRLD-MF there is induction of beclin 1, which forms the platform to recruit other interacting molecules to initiate autophagy. Knocking down the beclin 1 transcription factor Nrf2 and subsequent infection with SbRLD showed significantly lower organ parasites as compared to wild type BALB/c mice. Cessation of autophagy in SbRLD-MF at the later stage of infection is coupled with induction of miR-30a, whose binding to 3'UTR of beclin 1 leads to its post-transcriptional attenuation followed by rise in intracellular Ca++ and apoptosis. SbRLD mediated translocation of AP-1 transcription factor to the nucleus induce pri-miR-30a over-expression. Rise in Ca++ causes caspase 8 activtion leading to the cleavage of beclin 1 and initiation of apoptosis in SbRLD-MF. Apoptosis may favor parasite egress for cell to cell transmission. We also found that beclin 1 expression is present in splenocytes of kala-azar patients harbouring SbRLD but not SbSLD. Our results suggest that SbRLD has evolved a unique mechanism for its own benefit which explains, in part, the cause of aggressive pathology. Peritoneal exudate macrophages were isolated from mouse, grown in 60mm plates and infected with Leishmania donovani and total RNA was isolated from cells at 12, 18 and 24 hrs post infection. Leishmania infected macrophage miRNA expression signature was generated. Cells grown on 60mm plates and infected with Leishmania. The main objective of the microarray analysis of mmu-miRNA in antimony resistant and antimony sensitive Leishmania donovani infected macrophages are as follows: 1. To study how the expression of miRNA varies in either antimony resistant or antimony sensitive Leishmania infected macrophages as compared to the normal macrophages as a function of time. LPS was used as control. 2. To study the expression of those miRNAs which are differentially expressed in antimony resistant and antimony sensitive Leishmania infected macrophages at each time point post infection. 3. To identify those miRNAs which are responsible for degradation of autophagy initiating protein beclin 1 mRNA
Project description:Leishmania (L.) are obligated intracellular protozoan parasites that develop electively in macrophages. These cells that are acting as a safe shelter for the pathogens but also as their ultimate killer, making them the alpha and the omega during leishmaniasis diseases. Macrophages are able to secrete a remarkably diverse set of regulators known to influence the physiological functions and differentiation of neighboring cells to trigger an adaptive immune response of protective Th1-type cells, whereas parasites have developed a wide range of mechanisms to circumvent the hostâs immune responses. Most of our understanding of this host-parasite conflict, in the context of macrophage invasion by L. major metacyclic promastigotes, has been gleaned from studies investigating the macrophage responses at late and unique time points after infection. To investigate the dynamics of this duel, we have analyzed the transciptomic profile of monocyte-derived human macrophages at different time points during the first 24h upon in vitro infection using high throughput microarray platform. The gene expression profile of 17,838 genes showed high expression variability between the three human donors at different time points post infection. Cross comparison between the three donors allowed the identification of a common set of expressed genes coding for inflammatory and chemotactic molecules, transcription factors, apoptosis inhibition, glucose synthesis and heme metabolism. The findings presented in this work suggest that transcriptome dynamics of macrophages early during the first 24h post infection enable to identify novel key pathways deregulated upon L. major invasion. Our reported set of expressed genes will be useful in future rounds of data mining and functional analyses. In total 27 samples from three different donors were analyzed. For each donor, samples at 0h, 3h, 6h, 12h and 24h of culture were used as controls. For each donor, samples of cells infected with metacyclic Leishmania major parasites at 3h, 6h, 12h and 24h post-infection were analyzed.
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.
Project description:The susceptibility of macrophages to HIV-1 infection is modulated during monocyte differentiation. IL-27 is an anti-HIV cytokine that also modulates monocyte activation. Here, we present new evidence that IL-27 promotes monocyte differentiation into macrophages that are non-permissive for HIV-1 infection. While IL-27 treatment does not affect expression of macrophage differentiation markers or macrophage biological functions, it confers HIV resistance by down-regulating spectrin beta non-erythrocyte 1 (SPTBN1), a required host factor for HIV-1 infection. IL-27 down-regulates SPTBN1 through a TAK-1-mediated MAPK signaling pathway. Knockdown of SPTBN1 strongly inhibits HIV-1 infection of macrophages; conversely, overexpression of SPTBN1 markedly increases HIV susceptibility of IL-27 treated macrophages. Moreover, we demonstrate that SPTBN1 associates with HIV-1 gag proteins. Collectively, our results underscore the ability of IL-27 to protect macrophages from HIV-1 infection by down-regulating SPTBN1, thus indicating that SPTBN1 is an important host target to reduce HIV-1 replication in one major element of the viral reservoir. 2 samples with different treatments were analyzed. Genes with absolute fold change >= 5 were selected.