Young adult N2 Caenorhabditis elegans were infected with Enterococcus faecalis or Enterococcus faecium for 8 h to determine the transcriptional host response to each enterococcal species.
Both live and dead Enterococci activate Caenorhabditis elegans host defense via immune and stress pathways.
Specimen part, Treatment
View SamplesN2 young adult animals were analyzed four hours after exposure to wild-type Candida albicans DAY185, heat-killed C. albicans DAY185 and heat-killed Escherichia coli OP50, all on Brain Heart Infusion (BHI) agar. It was necessary to use heat-killed E. coli OP50 as a control for these experiments because live E. coli OP50 (the normal nematode food source) is pathogenic to nematodes on BHI agar. These data identify the C. elegans genes that are differentially regulated during nematode infection with a human fungal pathogen.
Candida albicans infection of Caenorhabditis elegans induces antifungal immune defenses.
No sample metadata fields
View SamplesVery little is known about how animals discriminate pathogens from innocuous microbes. To address this question, we examined infection-response gene induction in the nematode Caenorhabditis elegans. We focused on genes that are induced in C. elegans by infection with the bacterial pathogen Pseudomonas aeruginosa, but are not induced by an isogenic attenuated gacA mutant. Most of these genes are induced independently of known immunity pathways. We generated a GFP reporter for one of these genes, infection response gene 1 (irg-1), which is induced strongly by wild-type P. aeruginosa strain PA14, but not by other C. elegans pathogens or by other wild-type P. aeruginosa strains that are weakly pathogenic to C. elegans. To identify components of the pathway that induces irg-1 in response to infection, we performed an RNA interference screen of C. elegans transcription factors. This screen identified zip-2, a bZIP transcription factor that is required for inducing irg-1, as well as several other genes, and is important for defense against infection by P. aeruginosa. These data indicate that zip-2 is part of a specialized pathogen response pathway that is induced by virulent strains of P. aeruginosa and provides defense against this pathogen.
bZIP transcription factor zip-2 mediates an early response to Pseudomonas aeruginosa infection in Caenorhabditis elegans.
Time
View SamplesAnalysis of differential gene expression in C. elegans adults exposed to three different bacteria: E. coli strain OP50, wild-type P. aeruginosa PA14 and gacA mutant PA14. Samples were analyzed at 4 hours and 8 hours after exposure to the different bacteria. These studies identified C. elegans genes induced by pathogen infection.
p38 MAPK regulates expression of immune response genes and contributes to longevity in C. elegans.
Specimen part
View SamplesAnalysis of genes differentially expressed between daf-2(e1368) and daf-2(e1368);pmk-1(km25) and between daf-2(e1368) and daf-2(e1368);daf-16(mgDf47). These studies identified genes upregulated by wild-type PMK-1 and wild-type DAF-16.
p38 MAPK regulates expression of immune response genes and contributes to longevity in C. elegans.
Specimen part
View SamplesYoung adult fer-15;fem-1 Caenorhabditis elegans were infected with Staphylococcus aureus for 8 h to determine the transcriptional host response to Staphylococcus aureus. Analysis of differential gene expression in C. elegans young adults exposed to two different bacteria: E. coli strain OP50 (control), wild-type Staphylococcus aureus RN6390. Samples were analyzed at 8 hours after exposure to the different bacteria. These studies identified C. elegans genes induced by pathogen infection.
Distinct pathogenesis and host responses during infection of C. elegans by P. aeruginosa and S. aureus.
Disease, Disease stage
View SamplesThe nematode Caenorhabditis elegans offers currently untapped potential for carrying out high-throughput, live-animal screens of low molecular weight compound libraries to identify molecules that target a variety of cellular processes. We previously used a bacterial infection assay in C. elegans to identify 119 compounds that affect host-microbe interactions among 37,214 tested. We subsequently found that one of these small molecules, RPW-24, protects C. elegans from bacterial infection by stimulating the host immune response of the nematode. Using transcriptome profiling, epistasis pathway analyses with C. elegans mutants, and an RNAi screen, we showed that RPW-24 promotes resistance to Pseudomonas aeruginosa infection by inducing the transcription of a remarkably small number of C. elegans genes (~1.3% of all genes) in a manner that partially depends on the evolutionarily-conserved p38 MAP kinase pathway and the transcription factor ATF-7. These data demonstrated that the immunostimulatory activity of RPW-24 is required for its efficacy and define a novel C. elegans-based strategy to identify compounds with activity against antibiotic-resistant bacterial pathogens. Here we present the microarray data that were used to define the genes that are differentially regulated in wild-type nematodes following exposure to RPW-24.
Stimulation of host immune defenses by a small molecule protects C. elegans from bacterial infection.
Specimen part, Treatment
View SamplesMany pathogens secrete toxins that target key host processes resulting in the activation of immune pathways. The secreted Pseudomonas aeruginosa toxin Exotoxin A (ToxA) disrupts intestinal protein synthesis which triggers the induction of a subset of P. aeruginosa-response genes in the nematode Caenorhabditis elegans. We found that losing one ToxA-induced C. elegans gene, the Tribbles pseudokinase ortholog nipi-3, results in hypersusceptibility to both P. aeruginosa and ToxA. We determined that NIPI-3 mediates the post-developmental expression of intestinal immune genes and proteins and primarily functions in parallel to known immune pathways, including p38 PMK-1 MAPK signaling. Here we present the microarray data that was used to determine that (1) nipi-3 regulates immune gene expression and that (2) nipi-3 and pmk-1 regulate non-overlapping gene sets consistent with them functioning in parallel.
Tribbles ortholog NIPI-3 and bZIP transcription factor CEBP-1 regulate a Caenorhabditis elegans intestinal immune surveillance pathway.
Specimen part
View SamplesSalicylic acid (SA) is a critical molecule mediating plant innate immunity with an important role limiting the growth and reproduction of the virulent powdery mildew (PM) Golovinomyces orontii on Arabidopsis thaliana. To investigate this later phase of the PM interaction, and the role played by SA, we performed replicated global expression profiling for wild type and SA biosynthetic mutant ics1 Arabidopsis from 0 to 7 days post infection. We found that ICS1-impacted genes comprise 3.8% of profiled genes with known molecular markers of Arabidopsis defense ranked very highly by the multivariate empirical Bayes statistic (T2 statistic ((Tai and Speed, 2006)). Functional analyses of T2-selected genes identified statistically significant PM-impacted processes including photosynthesis, cell wall modification, and alkaloid metabolism that are ICS1-independent. ICS1-impacted processes include redox, vacuolar transport/secretion, and signaling. Our data also supports a role for ICS1 (SA) in iron and calcium homeostasis and identifies components of SA crosstalk with other phytohormones. Through our analysis, 39 novel PMimpacted transcriptional regulators were identified. Insertion mutants in one of these regulators, PUX2, results in significantly reduced reproduction of the powdery mildew in a cell death independent manner. Though little is known about PUX2, PUX1 acts as a negative regulator of Arabidopsis CDC48 (Rancour et al., 2004; Park et al., 2007), an essential AAA-ATPase chaperone that mediates diverse cellular activities including homotypic fusion of ER and Golgi membranes, ER-associated protein degradation, cell cycle progression, and apoptosis. Future work will elucidate the functional role of the novel regulator PUX2 in PM resistance.
Temporal global expression data reveal known and novel salicylate-impacted processes and regulators mediating powdery mildew growth and reproduction on Arabidopsis.
Age, Specimen part
View SamplesPluripotent-specific inhibitors (PluriSIns) make a powerful tool for studying the mechanisms that control the survival of human pluripotent stem cells (hPSCs). Here we characterize PluriSIn#2 as a novel selective indirect inhibitor of topoisomerase II alpha (TOP2A). We find that TOP2A is uniquely expressed in undifferentiated hPSCs, and that its inhibition results in their rapid cell death. These findings reveal a dependency of hPSCs on the activity of TOP2A, which can be harnessed for their selective elimination from culture.
Brief reports: Controlling the survival of human pluripotent stem cells by small molecule-based targeting of topoisomerase II alpha.
Specimen part, Cell line, Treatment
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