Cerebral organoids – three-dimensional cultures of human cerebral tissue derived from pluripotent stem cells – have emerged as models of human cortical development. However, the extent to which in vitro organoid systems recapitulate neural progenitor cell proliferation and neuronal differentiation programs observed in vivo remains unclear. Here we use single-cell RNA sequencing (scRNA-seq) to dissect and compare cell composition and progenitor-to-neuron lineage relationships in human cerebral organoids and fetal neocortex. Covariation network analysis using the fetal neocortex data reveals known and novel interactions among genes central to neural progenitor proliferation and neuronal differentiation. In the organoid, we detect diverse progenitors and differentiated cell types of neuronal and mesenchymal lineages, and identify cells that derived from regions resembling the fetal neocortex. We find that these organoid cortical cells use gene expression programs remarkably similar to those of the fetal tissue in order to organize into cerebral cortex-like regions. Our comparison of in vivo and in vitro cortical single cell transcriptomes illuminates the genetic features underlying human cortical development that can be studied in organoid cultures. Overall design: 734 single-cell transcriptomes from human fetal neocortex or human cerebral organoids from multiple time points were analyzed in this study. All single cell samples were processed on the microfluidic Fluidigm C1 platform and contain 92 external RNA spike-ins. Fetal neocortex data were generated at 12 weeks post conception (chip 1: 81 cells; chip 2: 83 cells) and 13 weeks post conception (62 cells). Cerebral organoid data were generated from dissociated whole organoids derived from induced pluripotent stem cell line 409B2 (iPSC 409B2) at 33 days (40 cells), 35 days (68 cells), 37 days (71 cells), 41 days (74 cells), and 65 days (80 cells) after the start of embryoid body culture. Cerebral organoid data were also generated from microdissected cortical-like regions from H9 embryonic stem cell derived organoids at 53 days (region 1, 48 cells; region 2, 48 cells) or from iPSC 409B2 organoids at 58 days (region 3, 43 cells; region 4, 36 cells).
Human cerebral organoids recapitulate gene expression programs of fetal neocortex development.
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View SamplesThe majority of babies in the US are formula-fed instead of breast fed. There are major differences in the composition of formulas and breast milk and yet little is known about metabolic differences in babies as the result of feeding these very different diets and how that might affect development or disease risk in later life. One concern is that soy-based formulas might have adverse health effects in babies as a result of the presence of low levels of estrogenic phytochemicals genistein and daidzein which are normally present in soy beans. In the current study, we used a piglet model to look at this question. Piglets were either fed breast milk from the sow or were fed two different infant formulas (cows milk-based or soy-based) from age 2 days to 21 days when pigs are normally weaned onto solid food. Blood glucose and lipids were measured. Formula-fed pigs were found to have lower cholesterol than breast fed piglets and in addition had larger stores of iron in their liver.Microarray analysis was carried out to see if changes in liver gene expression could explain these effects of formula feeding. It was found that overall gene expression profiles were influenced by formula feeding compared to breast fed neonates. Gender-independent and unique effects of formula influenced cholesterol and iron metabolism. Further, soy formula feeding in comparison to milk-based formula failed to reveal any estrogenic actions on hepatic gene expression in either male or female pigs.
Formula feeding alters hepatic gene expression signature, iron and cholesterol homeostasis in the neonatal pig.
Sex
View SamplesWe studied the synaptic activity-regulated gene expression response in the human genetic background using cultured human iPSC-derived (hiPSCd) neuronal networks and networks of hiPSCd neurons mixed with mouse primary neurons. Our results confirm that genetic changes affect the synaptic activity-regulated gene program, proposing a functional mechanism how they have driven evolution of human cognitive abilities. Overall design: We compared RNA profiles of untreated hiPSCd neurons and hiPSCd neurons treated with bicuculline and 4-aminopyridine for 1 or 4 hours. Samples were collected from hiPSCd neuron-only cultures and from co-cultures of hiPSCd neurons and mouse primary hippocampal neurons.
Networks of Cultured iPSC-Derived Neurons Reveal the Human Synaptic Activity-Regulated Adaptive Gene Program.
Specimen part, Subject
View SamplesThe gene expression pattern of spherical neural masses (SNM) derived from HPRT knockdown murine D3 stem cells during neuronal differentiation to final neurons was invesitigated by RNA-Seq based gene expression analysis and the results were interpreted by GO, GSEA and signaling pathway analyses with Avadis NGS and PANTHER Classification System. Overall design: For RNA-Seq experiment, total RNAs of HPRT knockdown and control SNMs were extracted time-sequentially during the SNM differentiation such as differentiation-day 0, 1, 2, 3, 4, 6, 8, 10, 12, and 14 to final neurons, and each prepared library applied to the HiSeq 2000 sequencer of Illumina for 50 cycles of single lane run.
The housekeeping gene hypoxanthine guanine phosphoribosyltransferase (HPRT) regulates multiple developmental and metabolic pathways of murine embryonic stem cell neuronal differentiation.
Specimen part, Cell line, Treatment, Subject
View SamplesNumerous neurological disorders, including Alzheimer's disease, display a sex-biased prevalence. To identify molecular correlates of this sex bias, we investigated sex-differences in molecular pathology in the hippocampus using the 5XFAD mouse model of Alzheimer's disease during early stages of disease progression (1, 2, and 4 months of age). Overall design: Hippocampal mRNA from 1, 2, and 4 month old male and female 5XFAD mice were analyzed by RNA sequencing of 5 biological replicates using an Illumina HiSeq 2500
Sex-biased hippocampal pathology in the 5XFAD mouse model of Alzheimer's disease: A multi-omic analysis.
Sex, Age, Specimen part, Cell line, Subject
View SamplesThe cellular response to DNA damage is mediated through multiple pathways that regulate and coordinate DNA repair, cell cycle arrest and cell death. We show that the DNA damage response (DDR) induced by ionizing radiation (IR) is coordinated in breast cancer cells by selective mRNA translation mediated by high levels of translation initiation factor eIF4G1. Increased expression of eIF4G1, common in breast cancers, was found to selectively increase translation of mRNAs involved in cell survival and the DDR, preventing autophagy and apoptosis (Survivin, HIF1, XIAP), promoting cell cycle arrest (GADD45a, p53, ATRIP, Chk1) and DNA repair (53BP1, BRCA1/2, PARP, Rfc2-5, ATM, MRE-11, others). Reduced expression of eIF4G1, but not its homolog eIF4G2, greatly sensitizes cells to DNA damage by IR, induces cell death by both apoptosis and autophagy, and significantly delays resolution of DNA damage foci with little reduction of overall protein synthesis. While some mRNAs selectively translated by higher levels of eIF4G1 were found to use internal ribosome entry site (IRES)-mediated alternate translation, most do not. The latter group shows significantly reduced dependence on eIF4E for translation, facilitated by an enhanced requirement for eIF4G1. Increased expression of eIF4G1 therefore promotes specialized translation of survival, growth arrest and DDR mRNAs that are important in cell survival and DNA repair following genotoxic DNA damage.
DNA damage and eIF4G1 in breast cancer cells reprogram translation for survival and DNA repair mRNAs.
Cell line
View SamplesIn this study we showed that rat XEN cells grown in the presence of a GSK3 inhibitor exhibited enhanced formation of cell contacts and decreased motility. In contrast, treatment with forskolin induced the PE formation and epithelial-mesenchymal transition (EMT) in rat XEN cells. Using microarray and real-time PCR assays, we found that VE versus PE formation of rat XEN cells was correlated with change in expression levels of VE or PE marker genes. Similar to forskolin, EMT was prompted upon treatment of rat XEN cells with recombinant parathyroid hormone related peptide (PTHRP), an activator of the cAMP pathway in vivo. Taken together, our data suggest that rat XEN cells are PrE-like cells. The activation of Wnt pathway in rat XEN cells leads to the acquisition of VE characteristics, whereas the activation of the PTHRP/cAMP pathway leads to EMT and the formation of PE.
Activation of the PTHRP/adenylate cyclase pathway promotes differentiation of rat XEN cells into parietal endoderm, whereas Wnt/β-catenin signaling promotes differentiation into visceral endoderm.
Specimen part
View SamplesSynaptic activity drives changes in gene expression to promote long-lasting adaptations of neuronal structure and function. One example of such an adaptive response is the buildup of acquired neuroprotection, a synaptic activity- and gene transcription-mediated increase in the resistance of neurons against harmful conditions. A hallmark of acquired neuroprotection is the stabilization of mitochondrial structure and function. We therefore re-examined previously identified sets of synaptic activity-regulated genes to identify genes that are directly linked to mitochondrial function. In mouse and rat primary hippocampal cultures synaptic activity caused an upregulation of glycolytic genes and a concomitant downregulation of genes required for oxidative phosphorylation, mitochondrial biogenesis and maintenance. Changes in metabolic gene expression were induced by action potential bursting, but not by glutamate bath application activating extrasynaptic NMDA receptors. The specific pattern of gene expression changes suggested that synaptic activity promotes a shift of neuronal energy metabolism from oxidative phosphorylation toward aerobic glycolysis, also known as Warburg effect. The ability of neurons to upregulate glycolysis has, however, been debated. We therefore used FACS sorting to show that, in mixed neuron glia co-cultures, activity-dependent regulation of metabolic gene expression occurred in neurons. Changes in gene expression were accompanied by changes in the phosphorylation-dependent regulation of the key metabolic enzyme, pyruvate dehydrogenase. Finally, increased synaptic activity caused an increase in the ratio of L-lactate production to oxygen consumption in primary hippocampal cultures. Based on these data we suggest the existence of a synaptic activity-mediated neuronal Warburg effect that may promote mitochondrial homeostasis and neuroprotection. Overall design: We compared the mRNA expression profile of primary hippocampal neurons after 4h of basal synaptic activity vs. 4h of action potential bursting. Two independent experiments with independent cell preparations were performed.
Synaptic Activity Drives a Genomic Program That Promotes a Neuronal Warburg Effect.
Specimen part, Cell line, Subject
View SamplesExpression analysis of 36 pancreatic ductal adenocarcinoma tumors and matching normal pancreatic tissue samples from pancreatic cancer patients of the Clinical Institute Fundeni (ICF) using Affymetrix U133 Plus 2.0 whole-genome chips.
Combined gene expression analysis of whole-tissue and microdissected pancreatic ductal adenocarcinoma identifies genes specifically overexpressed in tumor epithelia.
Subject
View SamplesThe formation of long-term memory requires signaling from the synapse to the nucleus to mediate neuronal activity-dependent gene transcription. Synapse-to-nucleus communication is initiated by influx of calcium ions through synaptic NMDA receptors and/or L-type voltage-gated calcium channels and involves the activation of transcription factors by calcium/calmodulin signaling in the nucleus. Recent studies have drawn attention to a new family of transcriptional regulators, the so-called calmodulin-binding transcription activator (CAMTA) proteins. CAMTAs are expressed at particularly high levels in the mouse and human brain, and we reasoned that, as calmodulin-binding transcription factors, CAMTAs may regulate the formation of long-term memory by coupling synaptic activity and calcium/calmodulin signaling to memory-related transcriptional responses. This hypothesis is supported by genetic studies that reported a correlation between CAMTA gene polymorphisms or mutations and cognitive capability in humans. Here, we show that acute knock-down of CAMTA1, but not CAMTA2, in the hippocampus of adult mice results in impaired performance in two memory tests, contextual fear conditioning and object-place recognition test. Short-term memory and neuronal morphology were not affected by CAMTA knock-down. Gene expression profiling in the hippocampus of control and CAMTA knock-down mice revealed a number of putative CAMTA1 target genes related to synaptic transmission and neuronal excitability. Patch clamp recordings in organotypic hippocampal slice cultures provided further evidence for CAMTA1-dependent changes in electrophysiological properties. In summary, our study provides experimental evidence that confirms previous human genetic studies and establishes CAMTA1 as a regulator of long-term memory formation. Overall design: We compared the mRNA expression profile of three groups, i.e. mice infected with a recombinant adeno-associated virus (rAAV) expressing a non-targeting control shRNA, mice infected with a rAAV expressing Camta1 targeting shRNA sequence A, and mice infected with a rAAV expressing Camta1 targeting shRNA sequence B. Three animals were used per group.
The calmodulin-binding transcription activator CAMTA1 is required for long-term memory formation in mice.
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