In C. elegans, ablation of germline stem cells (GSCs) extends lifespan, but also increases fat accumulation and alters lipid metabolism, raising the intriguing question of how these effects might be related. Here we show that a lack of GSCs results in a broad transcriptional reprogramming, in which the conserved detoxification regulator SKN-1/Nrf increases stress resistance, proteasome activity, and longevity. SKN-1 also activates diverse lipid metabolism genes and reduces fat storage, thereby alleviating the increased fat accumulation caused by GSC absence. Surprisingly, SKN-1 is activated by signals from this fat, which appears to derive from unconsumed yolk that was produced for reproduction. We conclude that SKN-1 plays a direct role in maintaining lipid homeostasis, in which it is activated by lipids. This SKN-1 function may explain the importance of mammalian Nrf proteins in fatty liver disease, and suggests that particular endogenous or dietary lipids might promote health through SKN-1/Nrf. Overall design: Samples were prepared from ~5,000 synchronized, L1 arrested day-one adult animals cultured at 25°C. Worms were synchronized by sodium hypochlorite (bleach) treatment, as previously described (Porta-de-la-Riva et al., 2012). Bleach solution (9 mL ddH2O; 1 mL 1 N NaOH; 4 mL Clorox bleach) was freshly prepared before each experiment. Worms were bleached for 5 minutes, washed 5x in M9, and arrested at the L1 stage at 25°C in M9 containing 10 µg/mL cholesterol. Feeding RNAi was started at the L1 stage. This approach only partially reduces skn-1 function, but allows analysis of larger samples than would be feasible with skn-1 mutants, which are sterile (Bowerman et al., 1992). Because these animals were not treated with FUdR, the WT adults contained an intact germline and eggs. As is explained in the Results section, we therefore confined our analysis to genes that were overrepresented in glp-1(ts) animals, which lack eggs and most of the germline, and established a high-confidence cutoff for genes that were upregulated by GSC absence as opposed to simply being expressed specifically in somatic tissues. RNA was extracted using the same protocol for qRT-PCR samples. Purified RNA samples were DNase treated and assigned a RIN quality score using a Bioanalyzer 2100 (Agilent Technologies, Santa Clara, CA). Only matched samples with high RIN scores were sent for sequencing. Single read 50 bp RNA sequencing with poly(A) enrichment was performed at the Dana-Farber Cancer Institute Center for Computational Biology using a HiSeq 2000 (Illumina, San Diego, CA). FASTQ output files were aligned to the WBcel235 (Feb 2014) C. elegans reference genome using STAR (Dobin et al., 2013). These files have been deposited at the Gene Expression Omnibus (GEO) with the accession number GSE63075. Samples averaged 75% mapping of sequence reads to the reference genome. Differential expression analysis was performed using a custom R and Bioconductor RNA-seq pipeline (http://bioinf.wehi.edu.au/RNAseqCaseStudy/) (Gentleman et al., 2004; Anders et al., 2013; R Core Team, 2014). Quantification of mapped reads in the aligned SAM output files was performed using featureCounts, part of the Subread package (Liao et al., 2013, 2014). We filtered out transcripts that didn't have at least one count per million reads in at least two samples. Quantile normalization and estimation of the mean-variance relationship of the log-counts was performed by voom (Law et al., 2014). Linear model fitting, empirical Bayes analysis and differential expression analysis was then conducted using limma (Smyth, 2005). To identify genes that are upregulated in a SKN-1-dependent manner by GSC loss, we sought genes for which glp-1(ts) expression was higher than WT, and for which glp-1(ts);skn-1(-) expression was reduced relative to glp-1(ts). To test for this pattern, if a gene's expression change was higher in the comparison of glp-1(ts) vs. WT and lower in the comparison of glp-1(ts);skn-1(-) vs. glp-1(ts), then we calculated the minimum (in absolute value) of the t-statistics from these two comparisons, and assessed the significance of this statistic by comparing to a null distribution derived by applying this procedure to randomly generated t-statistics. We corrected for multiple testing in this and the differential expression analysis using the false discovery rate (FDR) (Benjamini and Hochberg, 1995). Heatmaps were generated using heatmap.2 in the gplots package (Warnes et al., 2014). Functional annotations and phenotypes were obtained from Wormbase build WS246. SKN-1 transcription factor binding site analysis of hits was conducted with biomaRt, GenomicFeatures, JASPAR, MotifDb, motifStack, MotIV, and Rsamtools (Sandelin et al., 2004; Durinck et al., 2005; Durinck et al., 2009; Lawrence et al., 2013; Ou et al., 2013; Mercier and Gottardo, 2014; Shannon, 2014). JASPAR analysis was performed with the SKN-1 matrix MA0547.1 using 2 kb upstream sequences obtained from Ensembl WBcel235 (Staab et al., 2013). modENCODE SKN-1::GFP ChIP-seq analysis of hits was performed using biomaRt, ChIPpeakAnno, IRanges, and multtest (Durinck et al., 2005; Durinck et al., 2009; Gerstein et al., 2010; Zhu et al., 2010; Niu et al., 2011; Lawrence et al., 2013). SKN-1::GFP ChIP-seq peaks were generated by Michael Snyder's lab. We used the peak data generated from the first 3 larval stages: L1 (modENCODE_2622; GSE25810), L2 (modENCODE_3369), and L3 (modENCODE_3838; GSE48710). Human ortholog matching was performed using Wormbase, Ensembl, and OrthoList (Shaye and Greenwald, 2011). Gene lists were evaluated for functional classification and statistical overrepresentation with Database for Annotation, Visualization and Integrated Discovery (DAVID) version 6.7 (Dennis et al., 2003).
Lipid-mediated regulation of SKN-1/Nrf in response to germ cell absence.
Cell line, Subject
View SamplesApoptosis is deregulated in most, if not all, cancers, including hematological malignancies. In this study, we wanted to test whether primary acute myeloid leukemia (AML) samples are sensitive for inhibitor of apoptosis (IAP) protein antagonist treatment in vitro, and which AML subgroup might profit most from such a novel therapeutic strategy. We treated diagnostic samples of 67 adult AML patients with either cytarabine (ara-C) or IAP antagonist BV6 and correlated sensitivity with clinical, cytogenetic and molecular markers, and expression levels of selected genes involved in apoptosis. Primary AML samples showed differential sensitivity to treatment with either ara-C (40% sensitive, 17% intermediate, 43% resistant) or BV6 (51% sensitive, 21% intermediate, 28% resistant). Notably, 69% of ara-C resistant samples showed a good to fair response to IAP inhibition. Furthermore, combination treatment of ara-C with BV6 showed additive effects in most samples. Differences in sensitivity to IAP antagonist treatment correlated with significantly elevated expression levels of TNF and lower levels of XIAP in BV6 sensitive samples, as well as with NPM1 mutations. Gene expression profiling pointed to apoptosis-related pathways, which were specifically induced by IAP inhibition in sensitive samples. Thus, our results suggest IAP inhibition as a potential novel therapeutic option in AML.
Targeting inhibitor of apoptosis proteins by Smac mimetic elicits cell death in poor prognostic subgroups of chronic lymphocytic leukemia.
Sex, Age, Treatment
View SamplesInhibitor of apoptosis (IAP) proteins are expressed at high levels in CLL cells and may contribute to evasion of cell death leading to poor therapeutic outcome. Of note, prognostic unfavourable cases with e.g. non-mutated VH-status and TP53 mutation responded significantly better to BV6 than samples with unknown or favourable prognosis e.g. 13q deletion. The majority of cases with 17p deletion (10/12) and Fludarabine refractory cases were sensitive to BV6, indicating that BV6 acts independently of the p53 pathway. Importantly, BV6 dose-dependently induced cell death in 28 of 51 (54%) investigated patient samples while B cells from healthy donors were largely unaffected. BV6 also triggered cell death under survival conditions mimicking the microenvironment e.g. by adding CD40 ligand or in conditioned medium. Gene expression profiling identified cell death- and NF-kB-signaling among the top pathways regulated by BV6. This was confirmed by data showing that BV6 causes degradation of cIAP1 and cIAP2 and NF-kB pathway activation. BV6 induced cell death depended on production of reactive oxygen species, since addition of ROS scavengers significantly rescued BV6-triggerd cell death. In contrast, BV6 induced cell death independently of caspase activity, RIP1 activity or TNF-alpha, since zVAD.fmk, necrostatin-1 or TNF-alpha-blocking antibody Enbrel failed to protect against cell death. Of note, transcripts of ROS regulatory proteins were modulated by BV6. Thus, these data have important implications for developing new therapeutic strategies to overcome cell death resistance in CLL especially in poor prognostic subgroups.
Targeting inhibitor of apoptosis proteins by Smac mimetic elicits cell death in poor prognostic subgroups of chronic lymphocytic leukemia.
Sex, Age, Treatment
View SamplesTranscriptional profiles are increasingly used to investigate the severity, subtype and pathogenesis of disease. We now describe whole blood RNA signatures and local and systemic immune mediator levels in a large cohort of adults hospitalised with influenza from which extensive clinical and investigational data was obtained. Signatures reflecting interferon-related antiviral pathways were common up to day 4 of symptoms in cases not requiring mechanical ventilatory support; in those needing mechanical ventilation, an inflammatory, activated neutrophil and cell stress/death (bacterial) pattern was seen, even early after disease onset. Identifiable bacterial co-infection was not necessary for this bacterial signature but could enhance its development while attenuating the early viral signature. Our findings emphasise the importance of timing and severity in the interpretation of transcriptomic profiles and soluble mediator levels, and identify specific patterns of immune activation that may enable the development of novel diagnostics and therapeutics
Progression of whole-blood transcriptional signatures from interferon-induced to neutrophil-associated patterns in severe influenza.
Sex, Age, Race, Subject, Time
View SamplesTargeting components of the mitogen-activated protein kinase (MAPK) pathway prolongs survival of patients with advanced BRAFV600E melanomas but such an approach is not curative because of the rapid acquisition of numerous resistance mechanisms. Here we analyze melanoma cells that evade MAPK inhibitors by undergoing a senescence-like, slow-growth, phenotype, which leads to acquired resistance. The initial therapeutic response is characterized by an integrated stress response program, including stimulation of autophagic flux, activation of the endoplasmic reticulum machinery, and an enhanced ability of detoxifying reactive oxygen species. Reversibly senescent cells also exhibit an increase in mitochondrial genome copy number and a strong metabolic shift towards oxidative phosphorylation (OxPhos). Inducing mitochondrial dysfunction by co-targeting the MAPK pathway and mitochondrial Hsp90-directed protein folding with specific inhibitors prevented entry of cells into a reversibly senescent state, suppressed mitochondrial energy metabolism and augmented therapy response.
Targeting mitochondrial biogenesis to overcome drug resistance to MAPK inhibitors.
Disease, Disease stage, Cell line, Time
View SamplesWe have performed modular analyses to decipher the global transcriptional response and capture a breadth of distinct immune responses in the lungs and blood of mice infected or challenged with a broad spectrum of infectious pathogens, including parasites (Toxoplasma gondii), bacteria (Burkholderia pseudomallei), viruses (Influenza A virus and Respiratory Syncytial virus (RSV)) and fungi (Candida albicans), or allergens (House dust mite (HDM), systemic and intra-nasal challenge). In a distinct set of infectious diseases, we tested the blood modular transcriptional signatures in mice infected with Plasmodium chabaudi chabaudi (malaria), murine cytomegalovirus (MCMV), Listeria monocytogenes and chronic Burkholderia pseudomallei. We also investigated the transcriptional profiles of sorted CD4 T cells (total CD4+, CD4+ CD44 high and CD4+ CD44 low) from lung and blood samples from mice challenged with HDM allergen. Moreover, we used mice deficient in either Ifnar or Ifngr, or both, to reveal the individual roles of each pathway in controlling disease in mice infected with Toxoplasma gondii. Overall design: RNA-seq analysis of blood samples obtained from mice infected with Plasmodium chabaudi chabaudi, murine cytomegalovirus (MCMV), Listeria monocytogenes and chronic Burkholderia pseudomallei.
Transcriptional profiling unveils type I and II interferon networks in blood and tissues across diseases.
Specimen part, Subject
View SamplesWe have performed modular analyses to decipher the global transcriptional response and capture a breadth of distinct immune responses in the lungs and blood of mice infected or challenged with a broad spectrum of infectious pathogens, including parasites (Toxoplasma gondii), bacteria (Burkholderia pseudomallei), viruses (Influenza A virus and Respiratory Syncytial virus (RSV)) and fungi (Candida albicans), or allergens (House dust mite (HDM), systemic and intra-nasal challenge). In a distinct set of infectious diseases, we tested the blood modular transcriptional signatures in mice infected with Plasmodium chabaudi chabaudi (malaria), murine cytomegalovirus (MCMV), Listeria monocytogenes and chronic Burkholderia pseudomallei. We also investigated the transcriptional profiles of sorted CD4 T cells (total CD4+, CD4+ CD44 high and CD4+ CD44 low) from lung and blood samples from mice challenged with HDM allergen. Moreover, we used mice deficient in either Ifnar or Ifngr, or both, to reveal the individual roles of each pathway in controlling disease in mice infected with Toxoplasma gondii. Overall design: RNA-seq analysis of sorted CD4 T cells (total CD4+, CD4+CD44high and CD4+CD44low) from lung and blood samples obtained from mice challenged systemically with House dust mite (HDM) allergy.
Transcriptional profiling unveils type I and II interferon networks in blood and tissues across diseases.
Specimen part, Subject
View Samples