Protein synthesis belongs to the most energy consuming processes in the cell. Lowering oxygen tension below normal (hypoxia) causes a rapid inhibition of global mRNA translation due to the decreased availability of energy. Interestingly, subsets of mRNAs pursue active translation under such circumstances. In human fibrosarcoma cells (HT1080) exposed to prolonged hypoxia (36 h, 1% oxygen) we observed that transcripts are either increasingly or decreasingly associated with ribosomes localized at the endoplasmic reticulum (ER). In a global setting it turned out that only 31% of transcripts showing elevated total-RNA levels were also increasingly present at the ER in hypoxia. These genes, regulated by its expression as well as its ER-localization, belong to the gene ontologys hypoxia response, glycolysis and HIF-1 transcription factor network supporting the view of active mRNA translation at the ER during hypoxia. Interestingly, a large group of RNAs was found to be unchanged at the expression level, but translocate to the ER in hypoxia. Among these are transcripts encoding translation factors and >180 ncRNAs. In summary, we provide evidence that protein synthesis is favoured at the ER and, thus, partitioning of the transcriptome between cytoplasmic and ER associated ribosomes mediates adaptation of gene expression in hypoxia.
Hypoxia-induced gene expression results from selective mRNA partitioning to the endoplasmic reticulum.
Specimen part, Cell line
View SamplesThe biologic basis for NSCLC metastasis is not well understood. Here we addressed this deficiency by transcriptionally profiling tumors from a genetic mouse model of human lung adenocarcinoma that develops metastatic disease owing to the expression of K-rasG12D and p53R172H. As a tool to investigate the biologic basis for metastasis in this model and to query the roles of specific genes in this signature, we isolated adenocarcinoma cell lines from these mice and used them to develop a syngeneic tumor model in wild-type littermates. Transcriptional profiling of the highly metastatic subcutaneous tumors revealed genes that regulate, among other processes, epithelial-to-mesenchymal transition and intra-tumoral inflammation and angiogenesis, whereas the non-metastatic tumors did not.
Contextual extracellular cues promote tumor cell EMT and metastasis by regulating miR-200 family expression.
No sample metadata fields
View SamplesNeurons exploit mRNA localization and local translation to spatio-temporally regulate gene expression during development. Local translation and retrograde transport of transcription factors regulate nuclear gene expression in response to signaling events at distal neuronal ends. Whether epigenetic factors could also be involved in such regulation is not known. We report that the mRNA encoding the high mobility group N5 (HMGN5) chromatin binding protein localizes to growth cones of both neuronal-like cells and of hippocampal neurons. We show that Hmgn5 3UTR drives growth cone localization and translation of a reporter gene, and that HMGN5 can be retrogradely transported into the nucleus along neurites. Loss of HMGN5 function induces transcriptional changes and impairs neurite outgrowth while HMGN5 overexpression induces neurite outgrowth and global chromatin decompaction. Interestingly, control of both neurite outgrowth and chromatin structure is dependent on proper growth cone localization of Hmgn5 mRNA. Our results provide the first evidence that mRNA localization and local translation might serve as a mechanism to couple the dynamic neuronal outgrowth process with chromatin regulation in the nucleus.
Growth Cone Localization of the mRNA Encoding the Chromatin Regulator HMGN5 Modulates Neurite Outgrowth.
No sample metadata fields
View SamplesMetastatic disease is a primary cause of cancer-related death, and factors governing tumor cell metastasis have not been fully elucidated. Here we addressed this question by using tumor cell lines derived from mice that develop metastatic lung adenocarcinoma owing to expression of mutant K-ras and p53. A feature of metastasis-prone tumor cells that distinguished them from metastasis-incompetent tumor cells was plasticity in response to changes in their microenvironment. They transited reversibly between epithelial and mesenchymal states, forming highly polarized epithelial spheres in 3-dimensional culture that underwent epithelial-mesenchymal transition (EMT) following treatment with transforming growth factor-beta or injection into syngeneic mice. This plasticity was entirely dependent upon the microRNA-200 family, which decreased during EMT. Forced expression of miR-200 abrogated the capacity of these tumor cells to undergo EMT, invade, and metastasize and conferred transcriptional features of metastasis-incompetent tumor cells. We conclude that microenvironmental cues direct tumor metastasis by regulating miR-200 expression.
Contextual extracellular cues promote tumor cell EMT and metastasis by regulating miR-200 family expression.
Cell line
View SamplesThe Zeb1 transcriptional repressor plays a key role in metastasis through the down-regulation of genes that are strong inducers of epithelial differentiation and inhibitors of stem-ness. Here we report that Zeb1 controls the expression of numerous oncogenic and tumor suppressive microRNAs (miRs). Zeb1 stimulated pro-migratory cytoskeletal processes by down-regulating miR-34a and activated Rho GTPases through Arhgap1, a Cdc42 GTPase activating protein and novel miR-34a target gene. Poor-prognosis human lung adenocarcinomas were highly enriched in a cytoskeletal gene signature activated by miR-34a down-regulation. These findings suggest that Zeb1 regulates a miR network and drives pro-migratory cytoskeletal processes through miR-34a.
ZEB1 drives prometastatic actin cytoskeletal remodeling by downregulating miR-34a expression.
Specimen part
View SamplesThe inhibitory receptor Tim-3 has emerged as a critical regulator of the T cell dysfunction that develops in chronic viral infections and cancers. However, little is known regarding the signaling pathways that drive Tim-3 expression. Here, we demonstrate that IL-27 induces NFIL3, which promotes permissive chromatin remodeling of the Tim-3 locus and induces Tim-3 expression together with the immunosuppressive cytokine IL-10. We further show that the IL-27/NFIL3 signaling axis is crucial for the induction of Tim-3 in vivo. IL-27-conditioned Th1 cells exhibit reduced effector function and are poor mediators of intestinal inflammation. This inhibitory effect is NFIL3 dependent. In contrast, tumor-infiltrating lymphocytes (TILs) from IL-27R-/- mice exhibit reduced NFIL3, less Tim-3 expression and failure to develop dysfunctional phenotype, resulting in better tumor growth control. Thus, our data identify an IL-27/NFIL3 signaling axis as a key regulator of effector T cell responses via induction of Tim-3, IL-10, and T cell dysfunction.
An IL-27/NFIL3 signalling axis drives Tim-3 and IL-10 expression and T-cell dysfunction.
Sex, Specimen part
View SamplesWe used microarray analysis to investigate if keratinocytes excert an immuno-inflammatory response towards streptococcal M1 protein.
Vigilant keratinocytes trigger pathogen-associated molecular pattern signaling in response to streptococcal M1 protein.
Specimen part, Cell line
View SamplesWe used the flu mutant of Arabidopsis and a transgenic line that overexpresses the thylakoid-bound ascorbate peroxidase (tAPX) to address the interactions between different reactive oxygen species (ROS) signaling pathways. The conditional flu mutant of Arabidopsis accumulates excess protochlorophyllide in the dark within chloroplast membranes that upon illumination acts as a photosensitizer and generates singlet oxygen (1O2). Immediately after the release of singlet oxygen rapid changes in nuclear gene expression occur. Distinct sets of genes were activated that were different from those induced by other reactive oxygen species, superoxide or hydrogen peroxide (H2O2), suggesting that different types of active oxygen species activate distinct signaling pathways. It was not known whether the pathways operate separately or interact with each other. We have addressed this problem by modulating noninvasively the level of H2O2 in plastids by means of a transgenic line that overexpresses the thylakoid-bound ascorbate peroxidase (tAPX, line 14/2 PMID: 15165186). In the flu mutant overexpressing tAPX, the expression of most of the nuclear genes that were rapidly activated after the release of 1O2 was significantly higher in flu plants overexpressing tAPX, whereas in wild-type plants, overexpression of tAPX had only a very minor impact on nuclear gene expression. The results suggest that H2O2 antagonizes the 1O2-mediated signaling of stress responses as seen in the flu mutant. This cross-talk between H2O2- and 1O2-dependent signaling pathways might contribute to the overall stability and robustness of wild-type plants exposed to adverse environmental stress conditions.
Cross-talk between singlet oxygen- and hydrogen peroxide-dependent signaling of stress responses in Arabidopsis thaliana.
No sample metadata fields
View SamplesWe had evidence that TRIM5 regulates signal transduction, specifically NFkB and MAPK pathways. To test the role of endogenous TRIM5 we used the myelomonocytic leukemia cell line THP1. These cells were transduced with a lentiviral vector that delivers a miRNA engineered to knockdown TRIM5. The vector also encoded a puromycin-resistance cassette and transduced cells were selected in poold with puromycin. As a control, cells were transduced with a vector targeting luciferase instead of TRIM5.
TRIM5 is an innate immune sensor for the retrovirus capsid lattice.
Specimen part, Cell line
View SamplesClimate change and disease have large negative impacts on poultry production, but little is known about the interactions of responses to these stressors in chickens. Fayoumi (heat and disease resistant) and broiler (heat and disease susceptible) chicken lines were stimulated at 22 days of age, using a 2x2x2 factorial design including: breed (Fayoumi or broiler), inflammatory stimulus [lipopolysaccharide (LPS) or saline], and temperature (35°C or 25°C). Transcriptional changes in spleens were analyzed using RNA-sequencing on the Illumina HiSeq 2500. Thirty-two individual cDNA libraries were sequenced (four per treatment) and an average of 22 million reads were generated per library. Stimulation with LPS induced more differentially expressed genes (DEG, log2 fold change = 2 and FDR = 0.05) in the broiler (N=283) than the Fayoumi (N=85), whereas heat treatment resulted in fewer DEG in broiler (N=22) compared to Fayoumi (N=107). The double stimulus of LPS+heat induced the largest numbers of changes in gene expression, for which broiler had 567 DEG and Fayoumi had 1471 DEG of which 399 were shared between breeds. Further analysis of DEG revealed pathways impacted by these stressors such as Remodelling of Epithelial Adherens Junctions due to heat stress, Granulocyte Adhesion and Diapedesis due to LPS, and Hepatic Fibrosis/Hepatic Stellate Cell Activation due to LPS+heat. The genes and pathways identified provide deeper understanding of the response to the applied stressors and may serve as biomarkers for genetic selection for heat and disease tolerant chickens. Overall design: At 22 days of age, divergent chicken breeds (Fayoumi and broiler) were treated with a thermal treatment (heat stress at 35C, or thermoneutral at 25C as a control) for 3.5 hours, then stimulated subcutaneously with an inflammatory stimulus (LPS, or saline as a control) for another 3.5 hours. Chickens were euthanized and spleens were harvested. A total of 32 indivudally coded cDNA libraries were prepared using TruSeq v2 library preparation kit which selects for polyA mRNA. In this 2x2x2 full factorial design with the factors of breed, thermal treatment, and inflammatory stimulus, there were a total of 8 treatment groups. Each treatment group had a total of 4 animal biological replicates. Therefore, a total of 32 individual barcoded samples were sequenced. A total of 8 individually barcoded cDNA libraries were sequenced per lane using the HiSeq Illumina 2500, and we used 4 lanes total. Reads were mapped to Galgal 2.0.
Unique genetic responses revealed in RNA-seq of the spleen of chickens stimulated with lipopolysaccharide and short-term heat.
Subject
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