In an ongoing translational research program involving microarray-based expression profiles in pediatric septic shock, we have now conducted longitudinal studies focused on the temporal expression profiles of canonical signaling pathways and gene networks. Genome-level expression profiles were generated from whole blood-derived RNA samples of children with septic shock (n = 30 individual patients) corresponding to days 1 and 3 of admission to the pediatric intensive care unit. Based on sequential statistical and expression filters, day 1 and day 3 of septic shock were characterized by differential regulation of 2,142 and 2,504 gene probes, respectively, relative to normal control patients. Venn analysis demonstrated 239 unique genes in the day 1 data set, 598 unique genes in the day 3 data set, and 1,906 genes common to both data sets. Analyses targeted toward derivation of biological function from these data sets demonstrated time-dependent, differential regulation of genes involved in multiple canonical signaling pathways and gene networks primarily related to immunity and inflammation. Notably, multiple and distinct gene networks involving T cell- and MHC antigen-related biological processes were persistently downregulated from day 1 to day 3. Further analyses demonstrated large scale and persistent downregulation of genes corresponding to functional annotations related to zinc homeostasis. These data represent the largest reported cohort of patients with septic shock, which has undergone longitudinal genome-level expression profiling. The data further advance our genome-level understanding of pediatric septic shock and support novel hypotheses that can be readily tested at both the experimental and translational levels.
Genome-level longitudinal expression of signaling pathways and gene networks in pediatric septic shock.
No sample metadata fields
View SamplesNormal children, children with SIRS, children with sepsis, and children with septic shock.
Genomic expression profiling across the pediatric systemic inflammatory response syndrome, sepsis, and septic shock spectrum.
No sample metadata fields
View SamplesRationale: We previously generated genome-wide expression data in children with septic shock, based on whole blood-derive RNA, having the potential to lead the field into novel areas of investigation.
Validating the genomic signature of pediatric septic shock.
Sex
View SamplesGoal of the experiment: To identify correlated genes, pathways and groups of patients with systemic inflammatory response syndrome and septic shock that is indicative of biologically important processes active in these patients.
Genome-level expression profiles in pediatric septic shock indicate a role for altered zinc homeostasis in poor outcome.
No sample metadata fields
View SamplesWe considered the possibility that removal of E2F4, as a key regulator of cellular quiescence, would cause systemic perturbations in the expression of E2F4 bound genes involved in cell cycle and proliferation. To test whether these pertubrations were reflected in the adult tissues' gene expression programs, we compared the gene expression profile of E2F4 double knockout mice to the gene expression found in identical tissues from E2F4 heterozygous littermates, that are phenotypically normal. We selected liver, testes, and kidney to profile by gene expression analysis, because two of these tissues are affected at some point during development when E2F4 is missing.
Cell cycle genes are the evolutionarily conserved targets of the E2F4 transcription factor.
Sex, Age, Specimen part, Disease, Disease stage, Subject
View SamplesAutosomal-recessive loss of the NSUN2 gene has been recently identified as a causative link to intellectual disability disorders in humans. NSun2 is an RNA methyltransferase modifying cytosine-5 in transfer RNAs (tRNA). Whether NSun2 methylates additional RNA species is currently debated. Here, we adapted the individual-nucleotide resolution UV cross-linking and immunoprecipitation method (iCLIP) to identify NSun2-mediated methylation in RNA transcriptome. We confirm site-specific methylation in tRNA and identify messenger and non-coding RNAs as potential methylation targets for NSun2. Using RNA bisulfite sequencing we establish Vault non-coding RNAs as novel substrates for NSun2 and identified six cytosine-5 methylated sites. Furthermore, we show that loss of cytosine-5 methylation in Vault RNAs causes aberrant processing into argonaute-associating small RNA fragments (svRNA). Thus, impaired Vault non-coding RNA processing may be an important contributor to the etiology of NSUN2-deficieny human disorders. Overall design: mRNA-seq in Embryonic kidney (HEK293) cells transfected with siRNA against Nsun2 vs control
NSun2-mediated cytosine-5 methylation of vault noncoding RNA determines its processing into regulatory small RNAs.
Specimen part, Cell line, Subject
View SamplesBackground: Septic shock is a heterogeneous syndrome within which probably exist several biological subclasses. Discovery and identification of septic shock subclasses could provide the foundation for the design of more specifically targeted therapies. Herein we tested the hypothesis that pediatric septic shock subclasses can be discovered through genome-wide expression profiling. Methods: Genome-wide expression profiling was conducted using whole blood-derived RNA from 98 children with septic shock, followed by a series of bioinformatic approaches targeted at subclass discovery and characterization. Results: Three putative subclasses (subclasses A, B, and C) were initially identified based on an empiric, discovery-oriented expression filter and unsupervised hierarchical clustering. Statistical comparison of the 3 putative subclasses (ANOVA, Bonferonni correction, p < 0.05) identified 6,934 differentially regulated genes. K means clustering of these 6,934 genes generated 10 coordinately regulated gene clusters corresponding to multiple signaling and metabolic pathways, all of which were differentially regulated across the 3 subclasses. Leave one out cross validation procedures indentified 100 genes having the strongest predictive values for subclass identification. Forty-four of these 100 genes corresponded to signaling pathways relevant to the adaptive immune system and glucocorticoid receptor signaling, the majority of which were repressed in subclass A patients. Subclass A patients were also characterized by repression of genes corresponding to zinc-related biology. Phenotypic analyses revealed that subclass A patients were younger, had a higher illness severity, and a higher mortality rate than patients in subclasses B and C. Conclusions: Genome-wide expression profiling can identify pediatric septic shock subclasses having clinically relevant phenotypes.
Identification of pediatric septic shock subclasses based on genome-wide expression profiling.
Age, Specimen part, Disease, Disease stage
View SamplesThe NOTCH1 signaling pathway directly links extracellular signals with transcriptional responses in the cell nucleus and plays a critical role during T-cell development and in the pathogenesis over 50% of human T-cell lymphoblastic leukemia (T-ALL) cases. However, little is known about the transcriptional programs activated by NOTCH1. Using an integrative systems biology approach we show that NOTCH1 controls a feed-forward loop transcriptional network that promotes cell growth. Inhibition of NOTCH1 signaling in T-ALL cells led to a reduction in cell size and elicited a gene expression signature dominated by downregulated biosynthetic pathway genes. By integrating gene expression array and ChIP-on-chip data, we show that NOTCH1 directly activates multiple biosynthetic routes and induces c-MYC gene expression. Reverse engineering of regulatory networks from expression profiles showed that NOTCH1 and c-MYC govern two directly interconnected transcriptional programs containing common target genes that together regulate the growth of primary T-ALL cells. These results identify c-MYC as an essential mediator of NOTCH1 signaling and integrate NOTCH1 activation with oncogenic signaling pathways upstream of c-MYC.
NOTCH1 directly regulates c-MYC and activates a feed-forward-loop transcriptional network promoting leukemic cell growth.
No sample metadata fields
View SamplesThe CREB family of transcription factors stimulates cellular gene expression following phosphorylation at a conserved serine (Ser133 in CREB1) in response to cAMP and other extracellular signals. In order to characterize CREB target genes in various tissues, we give a cAMP agonist, forskolin (FSK), to cell lines or primary cultures and monitor the gene expression. To eliminate CREB-independent effects of FSK on cellular gene expression, we employed a dominant negative form of CREB called A-CREB, which dimerizes selectively with and blocks the DNA binding activity of CREB but not other bZIP family members. Therefore, genes that are induced by cAMP and the induction was blocked by A-CREB treatment likely represents CREB target genes.
Genome-wide analysis of cAMP-response element binding protein occupancy, phosphorylation, and target gene activation in human tissues.
No sample metadata fields
View SamplesWe examined the transcriptional function of cyclin D1 in mouse development using two approaches. First, we queried association of cyclin D1 with the genome of E14.5 mouse embryos using ChIP-on-chip approach. We observed binding of cyclin D1 to several promoter regions. Second, we compared gene expression profiles between wild-type and cyclin D1-null retinas. We observed several transcripts with altered levels in cyclin D1-null organs.
Transcriptional role of cyclin D1 in development revealed by a genetic-proteomic screen.
No sample metadata fields
View Samples