Down syndrome (trisomy 21) is the most common genetic cause of intellectual disability, but the precise molecular mechanisms underlying impaired cognition remain unclear. Elucidation of these mechanisms has been hindered by the lack of a model system that contains full trisomy of chromosome 21 (Ts21) in a human genome that enables normal gene regulation. To overcome this limitation,we created Ts21-induced pluripotent stem cells (iPSCs) from two sets of Ts21 human fibroblasts. One of the fibroblast lines had low level mosaicism for Ts21 and yielded Ts21 iPSCs and an isogenic control that is disomic for human chromosome 21 (HSA21). Differentiation of all Ts21 iPSCs yielded similar numbers of neurons expressingmarkers characteristic of dorsal forebrain neurons that were functionally similar to controls. Expression profiling of Ts21 iPSCs and their neuronal derivatives revealed changes in HSA21 genes consistent with the presence of 50% more genetic material as well as changes in non- HSA21 genes that suggested compensatory responses to oxidative stress. Ts21 neurons displayed reduced synaptic activity, affecting excitatory and inhibitory synapses equally. Thus, Ts21 iPSCs and neurons display unique developmental defects that are consistent with cognitive deficits in individuals with Down syndrome and may enable discovery of the underlying causes of and treatments for this disorder.
Deficits in human trisomy 21 iPSCs and neurons.
Specimen part, Time
View SamplesNumerous genetic variants associated with MEF2C are linked to autism, intellectual disability (ID) and schizophrenia (SCZ) – a heterogeneous collection of neurodevelopmental disorders with unclear pathophysiology. MEF2C is highly expressed in developing cortical excitatory neurons, but its role in their development remains unclear. We show here that conditional embryonic deletion of Mef2c in cortical and hippocampal excitatory neurons (Emx1-lineage) produces a dramatic reduction in cortical network activity in vivo, due in part to a dramatic increase in inhibitory and a decrease in excitatory synaptic transmission. In addition, we find that MEF2C regulates E/I synapse density predominantly as a cell-autonomous, transcriptional repressor. Analysis of differential gene expression in Mef2c mutant cortex identified a significant overlap with numerous synapse- and autism-linked genes, and the Mef2c mutant mice displayed numerous behaviors reminiscent of autism, ID and SCZ, suggesting that perturbing MEF2C function in neocortex can produce autistic- and ID-like behaviors in mice. Overall design: We carried out RNA-sequencing (RNA-seq) of somatosensory cortical tissue from control (Mef2cfl/fl) or Mef2c cKO (Mef2cfl/fl; Emx1-Cre) adult male mice. For the RNA-seq, three indipendent replicates were used for the mouse tissues.
MEF2C regulates cortical inhibitory and excitatory synapses and behaviors relevant to neurodevelopmental disorders.
Sex, Age, Specimen part, Cell line, Subject
View SamplesBy sequencing 36 cDNA libraries with Illumina technology, we identified genes differentially expressed in soybean plants in response to water deficit and genes that were either up- or down-regulated in different periods of the day. Of 54,175 predicted soybean genes (Glyma v1.1), 35.52% exhibited expression oscillations in a 24 h period. This number increased to 39.23% when plants were submitted to water deficit. Major differences in gene expression were observed in the control plants from late day (ZT16) until predawn (ZT20) periods, indicating that gene expression oscillates during the course of 24 h in normal development. Under water deficit, dissimilarity increased in all time-periods, indicating that the applied stress influenced gene expression. Results suggest that time of day, as well as light and temperature oscillations that occur considerably affect the regulation of water deficit stress response in soybean plants. Overall design: Gene expression analysis of soybean leaves under water deficit in 6 periods of day by sequencing 36 libraries, in triplicate, in Illumina platform.
Daytime soybean transcriptome fluctuations during water deficit stress.
Specimen part, Subject
View SamplesMurine gliomblastoma tumor progenitor cells TPCs with high and low EGFRvIII activity, pEGFR-Hi and pEGFR-Lo, showed differences in proliferation, differentiation, and invasion. Zs-Green-expressing
GBM heterogeneity as a function of variable epidermal growth factor receptor variant III activity.
Specimen part
View SamplesWe studied the transcriptional profile in yeast cells in response to heterologous expression of mammalian activated AKT1
Heterologous mammalian Akt disrupts plasma membrane homeostasis by taking over TORC2 signaling in Saccharomyces cerevisiae.
No sample metadata fields
View SamplesWe studied the transcriptional profile in response to acute PtdIns-4,5P2 depletion induced by heterologous expression of a plasma membrane-directed version of mammalian PI3K catalytic subunit (p110-CAAX).
The yeast cell wall integrity pathway signals from recycling endosomes upon elimination of phosphatidylinositol (4,5)-bisphosphate by mammalian phosphatidylinositol 3-kinase.
No sample metadata fields
View SamplesThe restoration of catalytic activity to mutant enzymes by small molecules is well-established for in vitro systems. Here we show that the protein tyrosine kinase Src R388A mutant can be rescued in live cells using the small molecule imidazole. Cellular rescue of a v-Src homolog was rapid and reversible and conferred predicted oncogenic properties. Using chemical rescue in combination with mass spectrometry, six known Src kinase substrates were confirmed, and several new protein targets identified. Chemical rescue data suggests that c-Src is active under basal conditions. Rescue of R388A c-Src also allowed contributions of Src to the MAP kinase pathway to be clarified. This chemical rescue approach is likely to be of broad utility in cell signaling.
Chemical rescue of a mutant enzyme in living cells.
No sample metadata fields
View SamplesThe Anopheles gambiae midgut harbors bacteria that proliferate upon a blood feed. We used microarrays to examine the midgut gene expression response at early stages (3hours) after an artifitial meal containing heat killed bacteria.
A peroxidase/dual oxidase system modulates midgut epithelial immunity in Anopheles gambiae.
Age, Specimen part
View SamplesIn mammals body temperature fluctuates diurnally around a mean value of 36-37°C. Despite the small differences between minimal and maximal values, body temperature rhythms can drive robust cycles in gene expression in cultured cells and, likely, in, animals. Here we studied the mechanisms responsible for the temperature-dependent expression of Cold- Inducible RNA-Binding Protein (CIRBP). In NIH3T3 fibroblasts exposed to simulated mouse body temperature cycles Cirbp mRNA oscillates about 3-fold in abundance, as it does in mouse liver. This daily mRNA accumulation cycle is directly controlled by temperature oscillations and does not depend on the cells’ circadian clocks. Here, we show that the temperature-dependent accumulation of Cirbp mRNA is controlled primarily by the regulation of splicing efficiency, defined as the fraction of Cirbp pre-mRNA processed into mature mRNA. As revealed by genome-wide “approach-to-steady-kinetics”, this posttranscriptional mechanism is wide-spread in the temperature-dependent control of gene expression. Overall design: Cultured NIH3T3 cells seeded and kept at 37C degree for 4 hours before being switched to 33C and 38C. After 16 hours of incubation the temperature was shifted to 38C and 33C, respectively. Sample were then taken at 0, 1, 3, 6 and 9 hour after the temperature shift. Paired-end, strand-specific, total RNA-seq was performed over the samples at the respective time points using the Illumina HiSeq2500 platform.
Temperature regulates splicing efficiency of the cold-inducible RNA-binding protein gene Cirbp.
Specimen part, Subject, Time
View SamplesThe leading cause of death in human patients with metastatic renal cell carcinoma (RCC) and malignant cancer in general is the dissemination of the primary tumor to secondary sites. The mechanisms by which RCC colonize the lung microenvironment during metastasis remain largely unknown. To investigate the mechanisms of lung colonization by tumor cells, we grafted human RCC cells with different lung metastatic activities in mice. Gene expression profiling of the mouse lung stromal compartment revealed a gene signature enriched for neutrophil-specific functions, induced preferentially by poorly metastatic cells. Analysis of the gene expression patterns in tumor cells and clinical specimens showed an inverse correlation between metastatic activity and the levels of a number of chemokines, including CXL5 ad IL8. Enforced depletion of CXCL5 and IL8 in tumor cells allowed us to establish a functional link between lung neutrophil infiltration, the secretion of chemokines by cancer cells and metastatic activity. Finally, we showed that human neutrophils displayed a higher cytotoxic activity toward poorly metastatic cells relative to highly metastatic cells. Together, these results support a model in which neutrophils recruited to the lung by tumor-secreted chemokines build an antimetastatic barrier and loss of those neutrophil chemokines in tumor cells is a critical rate-limiting step during lung metastatic seeding.
Neutrophil chemokines secreted by tumor cells mount a lung antimetastatic response during renal cell carcinoma progression.
Specimen part
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