MicroRNA expression profile in Leishmania donovani infected mouse macrophage
ABSTRACT: 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: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. Overall design: miRNA profiling of uninfected and Leishmania donovani infected THP1 differentiated macrophages after 15 h of infection was done to understand the mechanism of regulation of various genes.
Project description:Murine bone marrow derived macrophages were infected with Leishmania major or Leishmania donovania promastigotes, allowed to phagocytose latex beads or not treated. Gene expression profiles were compared to identify i) the effect of Leishmania infection; ii) the differences in effects between L. major and L. donovani; and iii) the effect of pahgocytosis of latex beads.
Project description:The mRNA expression of antimony resistant strains of Leishmania donovani was compared to the expression of the sensitive Leishmania donovani. The antimony resistant and sensitive Leishmania donovani were grown in complete M199 medium with 10% FCS and Penicillin streptomycin mixture. At stationary phase (5 day culture) cells were harvested in sterile Phosphate buffered saline and used for RNA isolation.
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.
Project description:Balb/c mice were infected with Leishmania donovani and liver mRNA expression were studied at two months post infection Total RNA was isolated from liver tissue from uninfected and two months infected mouse and whole genome microarray was performed
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.
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.