RNA from circulating blood reticulocytes was utilized to provide a robust description of genes transcribed at the final stages of erythroblast maturation. After depletion of leukocytes and platelets, Affymetrix HG-U133 arrays were hybridized with probe from total RNA isolated from blood sampled from 14 umbilical cords and 14 healthy adult humans.
The human reticulocyte transcriptome.
No sample metadata fields
View SamplesBackground/Aims: Ribavirin improves treatment response to pegylated-interferon (PEG-IFN) in chronic hepatitis C but the mechanism remains controversial. We studied correlates of response and mechanism of action of ribavirin in treatment of hepatitis C. Methods: 70 treatment-nave patients were randomized to 4 weeks of ribavirin (1000-1200 mg/d) or none, followed by PEG-IFN alfa-2a and ribavirin at standard doses and durations. Patients were randomized to undergo a liver biopsy either 24 hours before, or 6 hours after starting PEG-IFN. Hepatic gene expression was assessed by microarray and interferon-stimulated gene (ISG) expression quantified by the nCounter platform. Temporal changes in ISG expression were assessed by qPCR in peripheral-blood mononuclear cells (PBMC) and by serum levels of IP-10. Results: After four weeks of ribavirin monotherapy, HCV levels decreased by 0.50.5 log10 (p=0.009 vs. controls) and ALT by 33% (p<0.001). Ribavirin pretreatment, while modestly augmenting the induction of ISGs by PEG-IFN, did not modify the virological response to subsequent PEG-IFN and ribavirin treatment. However, biochemical, but not virological response to ribavirin monotherapy predicted response to subsequent combination treatment (rapid virological response, 71% in biochemical responders vs. 22% non-responders, p=0.01; early virological response, 100% vs. 68%, p=0.03, sustained virological response 83% vs. 41%, p=0.053). Ribavirin monotherapy lowered serum IP-10 levels but had no effect on ISG expression in PBMC. Conclusion: Ribavirin is a weak antiviral but its clinical effect in combination with PEG-IFN seems to be mediated by a separate, indirect mechanism, which may act to reset the interferon responsiveness in HCV-infected liver. Ribavirin pretreatment does not alter the clinical outcome of subsequent combination therapy.
Effect of ribavirin on viral kinetics and liver gene expression in chronic hepatitis C.
Specimen part, Disease, Disease stage, Treatment
View SamplesDiscriminating pathogenic bacteria from energy-harvesting commensals is key to host immunity. Using mutants defective in the enzymes of O-linked N-acetylglucosamine (O-GlcNAc) cycling, we examined the role of this nutrient-sensing pathway in the Caenorhabidits elegans innate immune response. Using whole genome transcriptional profiling, O-GlcNAc cycling mutants exhibited deregulation of unique stress- and immune-responsive genes as well as genes shared with the p38 MAPK/PMK-1 pathway. Moreover, genetic analysis showed that deletion of O-GlcNAc transferase (ogt-1) yielded animals hypersensitive to the human pathogen S. aureus but not to P. aeruginosa. Genetic interaction studies further revealed that nutrient-responsive OGT-1 acts through the conserved -catenin (BAR-1) pathway and in concert with p38 MAPK/PMK-1 to modulate the immune response to S. aureus. The participation of the nutrient sensor O-GlcNAc transferase in an immunity module conserved from C. elegans to humans reveals an unexplored nexus between nutrient availability and a pathogen-specific immune response.
Conserved nutrient sensor O-GlcNAc transferase is integral to C. elegans pathogen-specific immunity.
Treatment
View SamplesBody size varies enormously among mammalian species. In small mammals, body growth is typically suppressed rapidly, within weeks, whereas in large mammals, growth is suppressed slowly, over years, allowing for a greater adult size. We recently reported evidence that body growth suppression in rodents is caused in part by a juvenile genetic program that occurs in multiple tissues simultaneously and involves the downregulation of a large set of growth-promoting genes. We hypothesized that this genetic program is conserved in large mammals but that its time course is evolutionarily modulated such that it plays out more slowly, allowing for more prolonged growth. Consistent with this hypothesis, using expression microarray analysis, we identified a set of genes that are downregulated with age in both juvenile sheep kidney and lung. This overlapping gene set was enriched for genes involved in cell proliferation and growth and showed striking similarity to a set of genes downregulated with age in multiple organs of the juvenile mouse and rat, indicating that the multiorgan juvenile genetic program previously described in rodents has been conserved in the 80 million years since sheep and rodents diverged in evolution. Using microarray and real-time PCR, we found that the pace of this program was most rapid in mice, more gradual in rats, and most gradual in sheep. The findings support the hypothesis that a growth-regulating genetic program is conserved among mammalian species but that its pace is modulated to allow more prolonged growth and therefore greater adult body size in larger mammals.
Evolutionary conservation and modulation of a juvenile growth-regulating genetic program.
Specimen part
View SamplesSpleen conventional dendritic cells from NOD mice show a lower overall response to CpG-A compared to B6 cDCs.
Despite Increased Type 1 IFN, Autoimmune Nonobese Diabetic Mice Display Impaired Dendritic Cell Response to CpG and Decreased Nuclear Localization of IFN-Activated STAT1.
Sex, Specimen part
View SamplesTo study the physiological roles of polyamines, we have carried out a global microarray analysis on the effect of adding polyamines to an Escherichia coli mutant that lacks polyamines because of deletions in the genes in the polyamine biosynthetic pathway. Previously, we have reported that the earliest response to the polyamine addition is the increased expression of the genes for the glutamate dependent acid resistance system (GDAR). We also presented preliminary evidence for the involvement of rpoS and gadE regulators. In the current study further confirmation of the regulatory roles of rpoS and gadE is shown by a comparison of genome-wide expression profiling data from a series of microarrays comparing the genes induced by polyamine addition to polyamine-free rpoS+/gadE+ cells with genes induced by polyamine addition to polyamine-free rpoS and gadE cells. The results indicate that most of the genes in the E. coli GDAR system that are induced by polyamines require rpoS and gadE. Our data also show that, gadE is the main regulator of GDAR and other acid-fitness-island genes. Both polyamines and rpoS are necessary for the expression of gadE genes from the three promoters of gadE (P1, P2 and P3). The most important effect of polyamine addition is the very rapid post-transcriptional increase in the level of RpoS sigma factor. Our current hypothesis is that polyamines increase the level of RpoS protein, and that this increased RpoS level is responsible for the stimulation of gadE expression, which in turn induces the GDAR system in E. coli.
Polyamines Stimulate the Level of the σ38 Subunit (RpoS) of Escherichia coli RNA Polymerase, Resulting in the Induction of the Glutamate Decarboxylase-dependent Acid Response System via the gadE Regulon.
Treatment
View SamplesThe mammary gland at early stages of pregnancy undergoes fast cell proliferation, yet the mechanism to ensure its genome integrity is largely unknown. Here we show that pregnancy enhances expression of genes involved in numerous pathways, including most genes encoding replisomes. In mouse mammary glands, replisome genes are positively regulated by estrogen/ERa signaling but negatively regulated by BRCA1. Upon DNA damage, BRCA1 deficiency markedly enhances DNA replication initiation. BRCA1 deficiency also preferably impairs DNA replication checkpoints mediated by ATR and CHK1 but not by WEE1, which inhibits DNA replication initiation through CDC7-MCM2 pathway and enables BRCA1-deficient cells to avoid further genomic instability. Thus, BRCA1 and WEE1 inhibit DNA replication initiation in a parallel manner to ensure genome stability for mammary gland development during pregnancy.
BRCA1 represses DNA replication initiation through antagonizing estrogen signaling and maintains genome stability in parallel with WEE1-MCM2 signaling during pregnancy.
No sample metadata fields
View SamplesChemotherapy resistance presents a major hurdle for cancer treatment. We proposed to identify the molecular changes through which breast cancer cells evolve resistance to conventional treatment, here cisplatin, so targeted therapy can be developed. Candidate approach RNAi screening was combined with cisplatin treatment in order to identify molecular pathways conferring survival advantages. The screening identified ATP7A, a copper transport ATPase responsible for the intercellular movement and sequestering of cisplatin, as a therapeutic target. Copper chelation with tetrathiomolybdate (TM) targets ATP7A. TM in combination with cisplatin sensitized drug-resistant breast cancer cells. Allograft and xenograft models in aythymic mice treated with TM/cisplatin combination therapy inhibited tumor growth and increased survival compared with monotreated mice. Examination of the molecular effects of TM on cisplatin efficacy in drug-resistant tumors revealed reduced levels of APT7A, reduced cisplatin sequestering by ATP7A and increased nuclear availability of cisplatin. Further, we showed that TM treatment combined with cisplatin reduced the half-life of ATP7A in human breast cancer cell lines. This finding offered the potential to combat drug platinum-resistant tumors and sensitize patients to conventional breast cancer treatments by identifying and targeting resistant tumors unique molecular adaptations.
Ammonium tetrathiomolybdate treatment targets the copper transporter ATP7A and enhances sensitivity of breast cancer to cisplatin.
Cell line, Time
View SamplesRecent identification of IL28B gene polymorphisms associated with hepatitis C virus (HCV) clearance suggests a role for type III interferons (IFNs) in hepatitis C infection. The function of type III IFNs in intrinsic antiviral immunity is poorly understood. Here we show that HCV infection of primary human hepatocytes results in a robust induction of type III but not type I IFNs, leading to IFN- stimulated gene (ISG) expression. In addition, HCV infection elicits a much broader range of gene expression alterations in addition to ISG induction. The induction of type III IFNs is mediated by IRF3 and NFkB- dependent pathways. Type III IFN, aside from upregulating ISGs with a different kinetic profile, induces a distinct set of genes from type I IFN, potentially explaining the functional difference between the two types of IFNs. Chimpanzees undergoing experimental HCV infection demonstrated a prompt hepatic induction of IL28, associating with ISG upregulation, but minimal type I IFN induction. Analysis of liver biopsies from HCV-infected patients supported a close correlation among hepatic expression of IL28 and ISGs, but not with type I IFNs. Our study demonstrates that HCV infection results predominantly in type III IFN induction in the liver and the level of induction correlates with hepatic ISG levels, thus providing a mechanistic explanation for the association between IL28, ISG levels and recovery from HCV infection as well as a potential therapeutic strategy for the treatment of non-responders.
HCV infection induces a unique hepatic innate immune response associated with robust production of type III interferons.
Specimen part, Treatment, Time
View SamplesA chromosomal translocation fusion gene product EWS-WT1 is the defining genetic event in Desmoplastic Small Round Cell Tumor (DSRCT), a rare but aggressive tumor with a high rate of mortality. EWS-WT1 oncogene acts as an aberrant transcription factor that drives tumorigenesis, but the mechanism by which EWS-WT1 causes tumorigenesis is not well understood. To delineate the oncogenic mechanisms, we generated the EWS-WT1 fusion in the mouse using a gene targeting (knock-in) approach, enabling physiologic expression of EWS-WT1 under the native Ews promoter. We derived mouse embryonic fibroblasts (MEFs) and performed genome-wide expression profiling to identify transcripts directly regulated by EWS-WT1. Remarkably, expression of EWS-WT1 led to a dramatic induction of many neuronal genes. Notably, a neural reprogramming factor, ASCL1 (achaete-scute complex-like 1), was highly induced by EWS-WT1 in MEFs and in primary DSRCT. Further analysis demonstrated that EWS-WT1 directly binds to the proximal promoter region of ASCL1 and activates its transcription through multiple WT1-responsive elements. Depletion of EWS-WT1 in a DSRCT cell line resulted in severe reduction in ASCL1 expression and cell viability. Remarkably, when stimulated with neuronal induction media, cells expressing EWS-WT1 expressed neural markers and generated neurite-like projections. These results demonstrate for the first time that EWS-WT1 activates neural gene expression and is capable of directing partial neuronal differentiation, likely via ASCL1. These findings suggest that stimulating DSRCT tumor cells with biological or chemical agents that promote neural differentiation might be a useful approach to develop novel therapeutics against this incurable disease.
EWS-WT1 oncoprotein activates neuronal reprogramming factor ASCL1 and promotes neural differentiation.
Specimen part, Time
View Samples