We used Au nanoparticles (Au-NPs) as a model for studying particle specific effects of manufactured nanomaterials (MNMs) by examining the toxicogenomic responses in a model soil organism, free living nematode Caenorhabditis elegans. Global genome expression for nematodes exposed to 4-nm citrate-coated Au-NPs at the LC10 (5.9 mg L-1) revealed significant differential expression of 797 genes. The levels of expression for five genes (apl-1, dyn-1, act-5, abu-11, and hsp-4) were confirmed independently with qRT-PCR. Seven common biological pathways associated with 38 of these genes were identified. Activation of 26 pqn/abu genes from noncanonical Unfolded Protein Response (UPR) pathway and up-regulation of molecular chaperones (hsp-16.1, hsp-70, hsp-3 and hsp-4) were observed and are likely indicative of endoplasmic reticulum stress. Inhibition of abu-11 with RNAi showed increase in mortality in Au-NP exposed nematodes suggesting possible involvement of abu-11 (a gene associated with specific to C. elegans UPR) in a protective mechanism against Au-NPs. Exposure to Au-NPs also caused activation of genes involved in apoptosis and necrosis and resulted ultimately in 10% mortality. These results demonstrate that Au-NPs are bioavailable and cause adverse effects to a model ecoreceptor which activate both general and specific biological pathways.
Toxicogenomic responses of the model organism Caenorhabditis elegans to gold nanoparticles.
Treatment
View SamplesThe differentiated state of somatic cells provides barriers for the efficient derivation of induced pluripotent stem cells (iPSCs). To address why some cell types reprogram more readily than others, we studied the effect of combined modulation of cellular signaling pathways. This revealed that inhibition of TGF together with activation of Wnt signaling in presence of ascorbic acid allows >80% of murine fibroblasts to acquire pluripotency after one week of reprogramming factor expression. In contrast, hepatic progenitors and blood progenitors predominantly required only TGF inhibition or canonical Wnt activation, respectively, to reprogram at efficiencies approaching 100%. Strikingly, blood progenitors reactivated endogenous pluripotency loci in a highly synchronous manner. We further demonstrate that expression of specific chromatin-modifying enzymes and reduced TGF/MAP kinase activity are intrinsic properties associated with the unique reprogramming response of these cells. Together, our observations define novel cell type-specific requirements for the rapid and synchronous reprogramming of somatic cells.
Combinatorial modulation of signaling pathways reveals cell-type-specific requirements for highly efficient and synchronous iPSC reprogramming.
Specimen part, Time
View SamplesCharacterization of the transcriptome of normal and abnormal embryos. Overall design: Gene expression profiling of every mono and trisomy.
Human blastocysts of normal and abnormal karyotypes display distinct transcriptome profiles.
Specimen part, Subject
View SamplesThe regional specificity and timing of gene activation following chemotherapy, and how this relates to subsequent mucositis development is currently unknown. The aim of the study was therefore to determine the early time course of gene expression changes along the gastrointestinal tract (GIT) of the DA rat following irinotecan treatment, so as to provide an insight into the genetic component of mucositis.
Gene expression analysis of multiple gastrointestinal regions reveals activation of common cell regulatory pathways following cytotoxic chemotherapy.
Sex, Age
View SamplesThe human steroid receptor RNA activator (SRA) gene encodes both non-coding RNAs (ncRNAs) and protein-generating isoforms. However, the breadth of endogenous target genes that might be regulated by SRA RNAs remains largely unknown. To address this, we depleted SRA RNA in two human cancer cell lines (HeLa and MCF-7) with small interfering RNAs, then assayed for changes in gene expression by microarray analyses using Affymetrix HGU133+2 arrays. We also tested if SRA depletion affects estradiol-regulated genes in MCF-7 breast cancer cells.
Research resource: expression profiling reveals unexpected targets and functions of the human steroid receptor RNA activator (SRA) gene.
Cell line
View SamplesSimilar to the bone marrow, the mammary gland contains a distinct population of Hoechst-effluxing side population cells, MG-SPs. To better characterize MG-SPs, their microarray gene profiles were compared to the remaining cells, which retain Hoechst dye (MG-NSPs). For analysis, gene ontology (GO) that describes genes in terms of biological processes and ontology traverser (OT) that performs enrichment analysis were utilized. OT showed that MG-SP specific genes were enriched in the GO categories of cell cycle regulation and checkpoints, multi-drug resistant transporters, organogenesis, and vasculogenesis. The MG-NSP upregulated genes were enriched in the GO category of cellular organization and biogenesis which includes basal epithelial markers, p63, smooth muscle actin (SMA), myosin, alpha-6 integrin, cytokeratin (CK) 14, as well as luminal markers, CK8 and CD24. Additional studies showed that a higher percentage of MG-SPs exist in the G1 phase of the cell cycle compared to the MG-NSPs. G1 cell cycle block of MG-SPs may be explained by higher expression of cell cycle negative regulatory genes such as TGF-beta2 (transforming growth factor-beta2), IGFBP-5 (insulin like growth factor binding protein-5), P18 INK4C and Wnt-5a (wingless-5a). Accordingly, a smaller percentage of MG-SPs expressed nuclear b-catenin, possibly as a consequence of the higher expression of Wnt-5a. In conclusion, microarray gene profiling suggests that MG-SPs are a lineage deficient mammary gland sub-population expressing key genes involved in cell cycle regulation, development and angiogenesis.
Transcriptional profiling of mammary gland side population cells.
No sample metadata fields
View SamplesMicrocystin-LR (MC-LR), the most toxic member of microcystin family, inhibits protein phosphatase PP2A, triggers oxidative stress and induces hepatotoxicity. Gene expression profiling of MC-LR treated larvae using DNA microarray analysis revealed effects in the retinal visual cycle and pigmentation synthesis pathways that have not been previously associated with MC-LR. Liver-related genes were also differentially expressed. The microarray data were confirmed by quantitative real-time PCR. Our findings provide new evidence that microcystin-LR exposure of zebrafish larvae modulates the retinal visual cycle and pigmentation synthesis pathways and ultimately alter larval zebrafish behavior
Transcriptional and Behavioral Responses of Zebrafish Larvae to Microcystin-LR Exposure.
Specimen part
View SamplesRecently a genome of Russian individual (somatic DNA from blood) was sequenced (Skryabin et al. 2009). That study was continued to find a linkage between genetic differences in parental alleles and bias in biallelic expression of genes.
Individual genome sequencing identified a novel enhancer element in exon 7 of the CSFR1 gene by shift of expressed allele ratios.
No sample metadata fields
View SamplesGenome-wide mapping and characterization of novel Notch-regulated long non-coding RNAs in acute leukemia Overall design: Total RNA was extracted from samples using the RNeasy Plus mini kit (Life Technologies, Carlsbad, CA). Samples were then subject to PolyA selection (Figures 1E, 5F and 5G only) using oligo-dT beads (Life Technologies, Carlsbad, CA) or rRNA removal (all other samples) using the Ribo-Zero kit (Epicentre, Madison, WI) according to the manufacturers instructions. The resulting RNA samples were then used as input for library construction using the dUTP method as described by Parkhomchuck et al, 2009. RNA libraries were then sequenced on the Illumina HiSeq 2000 or 2500 using 50bp paired-end reads.
Genome-wide mapping and characterization of Notch-regulated long noncoding RNAs in acute leukemia.
No sample metadata fields
View SamplesSubstantial evidence implicates IGF-I signaling in the development and progression of breast cancer. To identify transcriptional targets of IGF action in breast cancer cells, we performed gene expression profiling (>22,000 RNA transcripts) of IGF-I-stimulated MCF-7 cells, a well characterized breast cancer cell line that is highly responsive to IGFs. We defined an IGF-I gene signature pattern of hundreds of genes either up-regulated or down-regulated at both 3 and 24 hrs in vitro. After removing genes considered generic to cell proliferation, the signature was examined in four different public profile datasets of clinical breast tumors (representing close to 1000 patients), as well as in profile datasets of experimental models for various oncogenic signaling pathways. Genes with early and sustained regulation by IGF-I were highly enriched for transcriptional targets of the estrogen, Ras, and PI3K/Akt/mTOR pathways. The IGF-I signature appeared activated in most estrogen receptor-negative (ER-) clinical breast tumors and in a substantial subset (~25%) of ER+ breast tumors. Patients with tumors showing activation of the IGF-I signature tended to have a shorter time to disease recurrence (including patients not receiving adjuvant therapy), both when considering all patients and the subset of ER+ patients. We found evidence for cross-talk and common transcriptional endpoints between the IGF-I and estrogen systems. Our results support the idea that the IGF-I pathway is one mechanism by which breast tumors may acquire hormone independence and a more aggressive phenotype.
Insulin-like growth factor-I activates gene transcription programs strongly associated with poor breast cancer prognosis.
No sample metadata fields
View Samples