Inflammatory gene expression in response to Francisella tularensis exposure in Balb/c mice
ABSTRACT: Francisella tularensis may enter the body thorugh the lungs and cause fatal infection. In this study the inflammatory response to the virulent strain of Francisella (Schu4) was mapped over a 96h time-course using a custom microarray. Overall design: Six groups of 4 mice were exposed to aerosolised Francisella tularensis and a three groups exposed to vehicle only control (media only). Following exposure mice were culled at 4 timepoints (1, 24, 48 and 96h). RNA was extracted and run on the custom array.
Project description:Francisella tularensis may enter the body thorugh the lungs and cause fatal infection. In this study the inflammatory response to the virulent strain of Francisella (Schu4) was mapped over a 96h time-course using a custom microarray. Six groups of 4 mice were exposed to aerosolised Francisella tularensis and a three groups exposed to vehicle only control (media only). Following exposure mice were culled at 4 timepoints (1, 24, 48 and 96h). RNA was extracted and run on the custom array.
Project description:Differential expression in human peripheral blood monocytes between F. novicida-infected and uninfected, and between Francisella tularensis tularensis isolate Schu S4 and uninfected. The goal was to examine genomewide transcriptional reponses to these two strains, and identify differentially-regulated genes that may help explain the virulence of Schu S4. Keywords: Immune Response, Human Monocytes, Bacteria, Francisella Overall design: Human monocytes were infected with the Schu S4 isolate of Francisella tularensis tularensis (n=4), with F. tularensis subspecies novicida isolate U112 (n=4) or were left uninfected (n=6). Gene expression values were calculated using the gcrma package in R and BioConductor, and limma to identify differentially expressed genes. Submitted here are expression values calculated using R 2.7.1 and BioConductor 2.2 (FreeBSD/amd64) but the original were done using R 2.6.1 and BioConductor 2.1 (FreeBSD/amd64). Twelve other chips were pooled with these 14 for preprocessing.
Project description:Raghunathan2010 - Genome-scale metabolic
network of Francisella tularensis (iRS605)
This model is described in the article:
Systems approach to
investigating host-pathogen interactions in infections with the
biothreat agent Francisella. Constraints-based model of
Raghunathan A, Shin S, Daefler
BMC Syst Biol 2010; 4: 118
BACKGROUND: Francisella tularensis is a prototypic example
of a pathogen for which few experimental datasets exist, but
for which copious high-throughout data are becoming available
because of its re-emerging significance as biothreat agent. The
virulence of Francisella tularensis depends on its growth
capabilities within a defined environmental niche of the host
cell. RESULTS: We reconstructed the metabolism of Francisella
as a stoichiometric matrix. This systems biology approach
demonstrated that changes in carbohydrate utilization and amino
acid metabolism play a pivotal role in growth, acid resistance,
and energy homeostasis during infection with Francisella. We
also show how varying the expression of certain metabolic genes
in different environments efficiently controls the metabolic
capacity of F. tularensis. Selective gene-expression analysis
showed modulation of sugar catabolism by switching from
oxidative metabolism (TCA cycle) in the initial stages of
infection to fatty acid oxidation and gluconeogenesis later on.
Computational analysis with constraints derived from
experimental data revealed a limited set of metabolic genes
that are operational during infection. CONCLUSIONS: This
integrated systems approach provides an important tool to
understand the pathogenesis of an ill-characterized biothreat
agent and to identify potential novel drug targets when rapid
target identification is required should such microbes be
intentionally released or become epidemic.
This model is hosted on
and identified by:
To cite BioModels Database, please use:
An enhanced, curated and annotated resource for published
quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
Public Domain Dedication for more information.
Project description:Prior aerosol exposure to F. tularensis subsp. tularensis, but not the live attenuated strain (LVS) of F. tularensis subsp. holarctica or F. novicida, significantly antagonized the transcriptional response in the lungs of infected mice exposed to aerosolized TLR4 ligand E. coli LPS. Overall design: The ability of a Toll-like receptor 4 (TLR4) agonist to induce a pulmonary inflammatory response in Francisella-infected animals was examined to distinguish between these two possible mechanisms, and also to investigate potential differences between three Francisella strains that exhibit varying levels of virulence in humans.
Project description:Phosgene is a lung damaging chemical warfare agent which can cause death by the inhalation route. In this study the inflammatory response to phosgene was mapped over a 96h time-course using a custom microarray in the Balb/c mouse. Overall design: Three groups of six mice were exposed to phosgene and a three groups exposed to an air only control. Following exposure mice were culled at 6 timepoints (1, 4, 7, 24, 48 and 96h). RNA was extracted and run on the custom array.
Project description:Phosgene is a lung damaging chemical warfare agent which can cause death by the inhalation route. In this study the inflammatory response to phosgene was mapped over a 96h time-course using a custom microarray in the Balb/c mouse. Three groups of six mice were exposed to phosgene and a three groups exposed to an air only control. Following exposure mice were culled at 6 timepoints (1, 4, 7, 24, 48 and 96h). RNA was extracted and run on the custom array.
Project description:Francisella tularensis, is an extremely virulent bacterium that can be transmitted naturally by blood sucking arthropods. During mammalian infection, F. tularensis infects numerous types of host cells, including erythrocytes. As erythrocytes do not undergo phagocytosis or endocytosis, it remains unknown how F. tularensis invades these cells. Furthermore, the consequence of inhabiting the intracellular space of red blood cells has not been determined. Here, we provide evidence indicating that residing within an erythrocyte enhances the ability of F. tularensis to colonize ticks following a blood meal. Overall design: mRNA profiles of F. tularensis with and without human erythrocyte exposure (5 replicates of each) were generated using high-throughput sequencing on an Illumina HiSeq 1500 in a 2X50 bp paired-end strategy
Project description:Francisella tularensis is classified as a Category A priority pathogen and causes fatal disseminated disease in humans upon inhalation of less than 50 bacteria. Although drugs are available for treatment, they are not ideal because of toxicity and delivery, and in some cases relapse upon withdrawal. We have an ongoing program in the development of novel FabI enoyl-ACP-reductase enzyme inhibitors for Francisella and other select agents. To establish ftFabI in F. tularensis as a clinically relevant drug target, we demonstrated that the enzyme is essential for growth in vitro and that ftfabI is not transcriptionally altered in the presence of exogenous fatty acids. Inhibition of ftFabI results in loss of viability that is not rescued by exogenous fatty acids supplementation. Importantly, whole-genome transcriptional profiling of F. tularensis with DNA microarrays from infected tissues revealed that ftfabI and de novo fatty acid biosynthetic genes are transcriptionally active during infection. This is the first demonstration that the FabI enoyl-ACP-reductase enzyme encoded by F. tularensis is essential and that de novo fatty acid biosynthetic components are transcriptionally active during infection in the mouse model tularemia. 2 C57BL/6 mice were infected with Francisella tularensis strain Schu4 via the intranasal route. Spleen tissue was harvested at 120 hours post-infection and total RNA was isolated immediately after harvest. RNA was pooled and host polyA-tailed RNA and ribosomal RNA were depleted using hybridization probes coupled to magnetic beads. The resulting sample was enriched for bacterial mRNA, and dye labeled using random hexamer primed RT and Cy3-labeled dUTPs. Labeled cDNA was hybridized in triplicate to custom whole genome cDNA microarrays and scanned using a GenePix 4000B.
Project description:These samples are part of an experiment comparing the expression profiles of Francisella tularensis novicida grown in chemically defined medium and bacteria isolated 24 hours post infection of J774 macrophages to identify virulence factors Custom microarray submitted previously was used as the platform (GPL20119). The samples submitted here were compared with samples submitted previously (GSM1673555-57 in GSE68478) and differentially expressed genes during the intra-macrophage growth were identified.
Project description:The highly infectious bacterium Francisella tularensis is a facultative intracellular pathogen, whose virulence requires proliferation inside host cells, including macrophages. Although some Francisella determinants of intracellular growth have been identified, much remains to be understood about the pathogenesis of this organism. In particular, how Francisella responds to its intracellular environment could provide clues about its intracellular biology and reveal pathogenic determinants based on their intracellular expression profiles. Here we have performed a global transcriptional profiling of the highly virulent F. tularensis subsp. tularensis Schu S4 strain during its intracellular cycle within primary murine macrophages. Phagocytosed bacteria rapidly responded to their intracellular environment and progressively altered their transcriptional profile over time. Differential gene expression profiles were revealed that correlated with specific intracellular locations of the bacteria. Upregulation of general and oxidative stress response genes was a hallmark of the early phagosomal and late endosomal stages, while induction of a subset of transport and metabolic genes characterized the cytosolic replication stages. Expression of the Francisella Pathogenicity Island (FPI) genes, the functions of which are associated with intracellular proliferation, increased during the intracellular cycle. Similarly, 27 chromosomal loci putatively encoding hypothetical, secreted, outer membrane proteins or transcriptional regulators were identified as upregulated during the intracellular cycle. In-frame deletion of FTT0383, the Schu S4 ortholog of fevR, of FTT0369c or FTT1676 abolished the ability of Schu S4 to either survive or proliferate intracellularly, demonstrating that bacterial factors of intracellular pathogenesis can be identified based on their intracellular expression profile. In conclusion, establishing the intracellular transcriptome of Francisella has revealed important aspects of its intracellular biology and identified novel virulence determinants of this pathogen. Keywords: Time series Overall design: Intracellular cycle within primary murine macrophages using the time series of zero, one, two, four, eight, twelve, sixteen and twenty-four hours