It is becoming better understood that radiation resistance in glioblastomas (GBMs) may be secondary to a self-renewing subpopulation of cells in the bulk tumor that form neurospheres in culture. This population has been referred to as Glioma stem cells (GSCs). One of the limitations regarding the use of GSCs is that these studies require fresh tumor biopsy samples obtained from patients, and can be extremely difficult to culture, propagate, and perform treatment-response assays. This report describes the generation of a self-renewing population of GSCs derived from commercially available U87 cells using NOD-SCID mice as carrier. The tumors were dissociated to obtain GSCs that demonstrate stem-like properties and high degree of chemo and radiation resistance. Pathological analysis of tumors obtained using GSCs exhibit all the histological hallmarks of human GBMs which is quite uncommon in GBM rodent models and hence could serve as a better model for pre-clinical study. We have shown that MGH87GSCs have an enhanced tumorogenicity than parental U87 and about 500 cells are sufficient to form tumors. To understand the transcriptome and accompanied proteome better, we explored the gene expression profiles of MGH87GSC and U87. We have shown that these GSCs are plastic like stem cells and can be directed towards a particular progeny within neural lineage by providing suitable growth factor. Our objective was to understand the genetic and biochemical mechanisms that control the self-renewal phenotype, asymmetric subdivision, chemo and radiation resistance and the role of the GSC niche in regulating the biological properties of GSC. Through this model we anticipate to devise therapeutic strategies to target this sub population of GSCs within GBMs to eradicate treatment resistance and tumor recurrence.
Cells isolated from residual intracranial tumors after treatment express iPSC genes and possess neural lineage differentiation plasticity.
Specimen part, Cell line
View SamplesFlowering plants have immotile sperm that develop within pollen and must be carried to female gametes by a pollen tube. The pollen tube engages in molecular interactions with several cell types within the pistil and these interactions are essential for successful fertilization. We identified a group of three closely related pollen tube-expressed MYB transcription factors (MYB97, MYB101, MYB120), which are required for proper interaction of the pollen tube with the female gametophyte. These transcription factors are transcriptionally induced during growth in the pistil. They regulate a transcriptional network leading to proper differentiation and maturation of the pollen tube, promoting proper pollen tube-ovule interactions resulting in sperm release and double fertilization.
Three MYB transcription factors control pollen tube differentiation required for sperm release.
Specimen part
View SamplesNeutrophils are short-lived innate immune cells. Upon encountering appropriate stimuli, neutrophils generate and release neutrophil extracellular traps (NETs), primarily via NADPH oxidase (Nox)-dependent (~2 hours) or Nox-independent NETosis (~15-60 minutes). Ironically, DNA transcription in dying neutrophils remains an enigma. We hypothesized that transcriptional activation, regulated by NETosis-specific kinases, is important to drive the chromatin decondensation necessary for NETosis. For the first time, we show here that (i) the degree of NETosis corresponds to the degree of genome-wide transcription; (ii) kinase-specific transcriptional activation reflects transcriptional firing during different types of NETosis; and (iii) Transcriptomics suggests that NETosis could differentially regulate inflammation. Therefore, we propose that the initial steps of transcriptional firing, but neither transcription per se help to drive NETosis.
Transcriptional firing helps to drive NETosis.
Sex, Specimen part, Disease
View SamplesPollen tubes extend through pistil tissues and are guided to ovules where they release sperm for fertilization. Although pollen tubes can germinate and elongate in a synthetic medium, their trajectory is random and their growth rates are slower compared to growth in pistil tissues. Furthermore, interaction with the pistil renders pollen tubes competent to respond to guidance cues secreted by specialized cells within the ovule. The molecular basis for this potentiation of the pollen tube by the pistil remains uncharacterized.
Penetration of the stigma and style elicits a novel transcriptome in pollen tubes, pointing to genes critical for growth in a pistil.
Specimen part
View SamplesStabilin-1/CLEVER-1 is a multidomain protein present in lymphatic and vascular endothelial cells and in M2 immunosuppressive macrophages. Stabilin-1 functions in scavenging, endocytosis and leukocyte adhesion to and transmigration through the endothelial cells. We have analyzed the putative functions of Stabilin-1 in blood monocytes and found that in healthy individuals 60-80% of both CD14+CD16- and CD14+C16+ monocytes, but not CD14dimCD16+ monocytes, expressed Stabilin-1 on the surface. Microarray and RNAseq analysis was performed to get more insight into the effect of Stabilin-1 expression on human monocytes transcriptome. Overall design: The transcriptome of human monocytes transfected with Stabilin-1 siRNA was compared to that of control siRNA transfected monocytes
Monocyte Stabilin-1 Suppresses the Activation of Th1 Lymphocytes.
No sample metadata fields
View SamplesHistone H3K4 methylation is connected to gene transcription from yeast to humans, but its mechanistic role in transcription and chromatin dynamics remains poorly understood. Here, we investigated the functions for Set1 and Jhd2, the sole H3K4 methyltransferase and H3K4 demethylase, respectively, in S. cerevisiae. Our data show that Set1 and Jhd2 predominantly co-regulate transcription. To further understand the role for H3K4 methylation, we overexpressed Flag epitope-tagged SET1-G990E (a dominant hyperactive allele of SET1) in yeast using the constitutive ADH1 promoter (ADH1p). As a control, we also overexpressed Flag epitope-tagged wild type SET1 in yeast. Analysis of gene expression in set1-null, jhd2-null and wild type SET1 or hypeactive SET1-G990E overexpressing mutants together revealed that the transcriptional regulation at a sub-set of genes, inclduing those governing glycogen metabolism and ribosome biogenesis, is highly sensitive to any change (i.e., loss or gain) in H3K4 methylation levels. Overall, we find combined activities of Set1 and Jhd2 via dynamic modulation of H3K4 methylation contribute to positive or negative transcriptional regulation at shared target genes. Overall design: Gene expression changes were generated from five different yeast strains representing wild type control, set1 null and jhd2 null mutants, and wild type SET1 or dominant hyperacive SET1-G990E overexpressing mutants. Three independent biological samples were grown for each strain, total RNA was isolated, libraries were prepared, sequenced, and analyzed separately.
Counteracting H3K4 methylation modulators Set1 and Jhd2 co-regulate chromatin dynamics and gene transcription.
Cell line, Subject
View SamplesWe compared gene expression in the Drosophila fat body on control and high-sugar diets in order to gain insight into the role of this organ during caloric overload. Differential expression analysis revealed changes in gene expression suggestive of a role for CoA metabolism in the ability to tolerate high-sugar feeding. This led us to perform biochemical and mutant studies supporting a model where CoA is limiting in the face of caloric overload. Overall design: Wild-type Drosophila were reared on control (0.15M sucrose) and high-sugar (0.7M sucrose) diets until the wandering stage. Fat bodies were isolated and RNA extracted to determine the effects of diet on gene expression using Illumina RNA-seq.
CoA protects against the deleterious effects of caloric overload in Drosophila.
Sex, Specimen part, Subject
View SamplesParkinson's disease pathogenesis proceeds through several phases, culminating in the loss of dopaminergic neurons of the substantia nigra (SN). Although the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of oxidative SN injury is frequently used to study degeneration of dopaminergic neurons in mice and non-human primates, an understanding of the temporal sequence of molecular events from inhibition of mitochondrial complex 1 to neuronal cell death is limited. Here, microarray analysis and integrative data mining were used to uncover pathways implicated in the progression of changes in dopaminergic neurons after MPTP administration. This approach enabled the identification of small, yet consistently significant, changes in gene expression within the SN of MPTP-treated animals. Such an analysis disclosed dysregulation of genes in three main areas related to neuronal function: cytoskeletal stability and maintenance, synaptic integrity, and cell cycle and apoptosis. The discovery and validation of these alterations provide molecular evidence for an evolving cascade of injury, dysfunction, and cell death.
Dysregulation of gene expression in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned mouse substantia nigra.
Sex, Age, Specimen part
View SamplesExpression profiling of Xenografts of Hepatocellular Carcinoma
Bevacizumab and rapamycin induce growth suppression in mouse models of hepatocellular carcinoma.
Specimen part
View SamplesNoncoding RNAs (ncRNAs) are emerging as key molecules in human cancer, with the potential to serve as novel markers of disease and to reveal uncharacterized aspects of tumor biology. Here we discover 121 unannotated prostate cancer–associated ncRNA transcripts (PCATs) by ab initio assembly of high-throughput sequencing of polyA+ RNA (RNA-Seq) from a cohort of 102 prostate tissues and cells lines. We characterized one ncRNA, PCAT-1, as a prostate-specific regulator of cell proliferation and show that it is a target of the polycomb repressive complex 2 (PRC2). We further found that patterns of PCAT-1 and PRC2 expression stratified patient tissues into molecular subtypes distinguished by expression signatures of PCAT-1–repressed target genes. Taken together, our findings suggest that PCAT-1 is a transcriptional repressor implicated in a subset of prostate cancer patients. These findings establish the utility of RNA-Seq to identify disease-associated ncRNAs that may improve the stratification of cancer subtypes. Overall design: 21 prostate cell lines sequenced on the Illumina Genome Analyzer and GAII. Variable number of replicates per sample. RNA-Seq data from prostate cancer tissues used in this study will be made available on dbGAP.
Transcriptome sequencing across a prostate cancer cohort identifies PCAT-1, an unannotated lincRNA implicated in disease progression.
No sample metadata fields
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