Single-cell RNA sequencing (scRNA-seq) offers new possibilities to address biological and medical questions. However, systematic comparisons of the performance of diverse scRNA-seq protocols are lacking. We generated data from 583 mouse embryonic stem cells to evaluate six prominent scRNA-seq methods: CEL-seq2, Drop-seq, MARS-seq, SCRB-seq, Smart-seq and Smart-seq2. While Smart-seq2 detected the most genes per cell and across cells, CEL-seq2, Drop-seq, MARS-seq and SCRB-seq quantified mRNA levels with less amplification noise due to the use of unique molecular identifiers (UMIs). Power simulations at different sequencing depths showed that Drop-seq is more cost-efficient for transcriptome quantification of large numbers of cells, while MARS-seq, SCRB-seq and Smart-seq2 are more efficient when analyzing fewer cells. Our quantitative comparison offers the basis for an informed choice among six prominent scRNA-seq methods and provides a framework for benchmarking further improvements of scRNA-seq protocols. Overall design: J1 mESC in two replicates per library preparation method.
A systematic evaluation of single cell RNA-seq analysis pipelines.
Cell line, Subject
View SamplesBackground Single-cell RNA-sequencing (scRNA-seq) experiments typically analyze hundreds or thousands of cells after amplification of the cDNA. The high throughput is made possible by the early introduction of sample-specific bar codes (BCs), and the amplification bias is alleviated by unique molecular identifiers (UMIs). Thus, the ideal analysis pipeline for scRNA-seq data needs to efficiently tabulate reads according to both BC and UMI. Findings zUMIs is a pipeline that can handle both known and random BCs and also efficiently collapse UMIs, either just for exon mapping reads or for both exon and intron mapping reads. If BC annotation is missing, zUMIs can accurately detect intact cells from the distribution of sequencing reads. Another unique feature of zUMIs is the adaptive downsampling function that facilitates dealing with hugely varying library sizes but also allows the user to evaluate whether the library has been sequenced to saturation. To illustrate the utility of zUMIs, we analyzed a single-nucleus RNA-seq dataset and show that more than 35% of all reads map to introns. Also, we show that these intronic reads are informative about expression levels, significantly increasing the number of detected genes and improving the cluster resolution. Conclusions zUMIs flexibility makes if possible to accommodate data generated with any of the major scRNA-seq protocols that use BCs and UMIs and is the most feature-rich, fast, and user-friendly pipeline to process such scRNA-seq data. Overall design: HEK293T cells were sequenced using the mcSCRB-seq protocol (Bagnoli et al., 2017)
zUMIs - A fast and flexible pipeline to process RNA sequencing data with UMIs.
Cell line, Subject
View SamplesMany library preparation methods are available for gene expression quantification. Here, we sequenced and analysed Universal Human Reference RNA (UHRR) prepared using Smart-Seq2, TruSeq (public data) and a protocol using unique molecular identifiers (UMIs) that all include the ERCC spike-in mRNAs to investigate the effects of amplification bias on expression quantification. Overall design: UHRR 10 and 12 replicates for Smart-seq2 and UMI-seq library preparation methods, respectively.
The impact of amplification on differential expression analyses by RNA-seq.
No sample metadata fields
View SamplesWe explored the connection between C/EBPa (CCAAT/enhancer binding protein a) and Wnt signaling in gut homeostasis and carcinogenesis. C/EBPa was expressed in human and murine intestinal epithelia in the transit amplifying region of the crypts and was absent in intestinal stem cells and Paneth cells with activated Wnt signaling. In human colorectal cancer and murine APCMin/+ polyps, C/EBPa was absent from nuclear ß-catenin–positive tumor cells. In chemically induced intestinal carcinogenesis, C/EBPa KO in murine gut epithelia increased tumor volume. C/EBPa deletion extended the S-phase cell zone in intestinal organoids and activated typical proliferation gene expression signatures, including that of Wnt target genes. Genetic activation of ß-catenin in organoids attenuated C/EBPa expression. Comparing gene expression of wild type and C/EBPa KO organoids by RNA sequencing aimed to identify C/EBPa dependent alterations in gene expression. Overall design: These data suggest homeostatic and oncogenic suppressor functions of C/EBPa in the gut by restricting Wnt signaling.
A C/EBPα-Wnt connection in gut homeostasis and carcinogenesis.
Specimen part, Subject
View SamplesWe analyzed the transcriptome of the C57BL/6J mouse hypothalamus, hippocampus, neocortex, and cerebellum to determine estrous cycle-specific changes in these four brain regions. We found almost 16,000 genes are present in one or more of the brain areas but only 210 genes, ~1.3%, are significantly changed as a result of the estrous cycle. The hippocampus has the largest number of differentially expressed genes (DEGs) (82), followed by the neocortex (76), hypothalamus (63), and cerebellum (26). Most of these DEGs (186/210) are differentially expressed in only one of the four brain regions. A key finding is the unique expression pattern of growth hormone (Gh) and prolactin (Prl). Gh and Prl are the only DEGs to be expressed during only one stage of the estrous cycle (metestrus). To gain insight into the function of the DEGs, we examined gene ontology and phenotype enrichment and found significant enrichment for genes associated with myelination, hormone stimulus, and abnormal hormone levels. Additionally, 61 of the 210 DEGs are known to change in response to estrogen in the brain. 50 genes differentially expressed as a result of the estrous cycle are related to myelin and oligodendrocytes and 12 of the 63 DEGs in the hypothalamus are oligodendrocyte- and myelin-specific genes. This transcriptomic analysis reveals that gene expression in the female mouse brain is remarkably stable during the estrous cycle and demonstrates that the genes that do fluctuate are functionally related. Overall design: Hypothalamus, hippocampus, neocortex, and cerebellum mRNA from adult female C57BL/6J (B6) mice were analyzed by RNA sequencing of 3 biological replicates for each of the 4 stages of the estrous cycle using an Illumina HiSeq 2500
The stability of the transcriptome during the estrous cycle in four regions of the mouse brain.
Sex, Age, Specimen part, Cell line, Subject
View SamplesA variety of neurological disorders, including Alzheimer's disease, Parkinson's disease, major depressive disorder, dyslexia and autism, are differentially prevalent between females and males. To better understand the possible molecular basis for the sex-biased nature of neurological disorders, we measured both mRNA and protein in the hippocampus of female and male mice at 1, 2, and 4 months of age with RNA-sequencing and mass-spectrometry respectively. Differential expression analyses identify 2699 genes that are differentially expressed between animals of different ages. 198 transcripts are differentially expressed between females and males at one or more ages. The number of transcripts that are differentially expressed between females and males is greater in adult animals than in younger animals. Additionally, we identify 69 transcripts that show complex and sex-specific patterns of temporal regulation across all ages, 8 of which are heat-shock proteins. We also find a modest correlation between levels of mRNA and protein in the mouse hippocampus (Rho = 0.53). This study adds to the substantial body of evidence for transcriptomic regulation in the hippocampus during postnatal development. Additionally, this analysis reveals sex differences in the transcriptome of the developing mouse hippocampus, and further clarifies the need to include both female and male mice in longitudinal studies involving molecular changes in the hippocampus. Overall design: Hippocampal mRNA from 1, 2, and 4 month old male and female B6 mice were analyzed by RNA sequencing of 5 biological replicates using an Illumina HiSeq 2500
Sex differences in the molecular signature of the developing mouse hippocampus.
Sex, Age, Specimen part, Cell line, Subject
View SamplesGastric cancer is still one of the most common causes of cancer-related death worldwide, which is mainly attributable to late diagnosis and poor treatment options. Infection with H. pylori, different environmental factors and genetic alterations are known to influence the risk of developing gastric tumors. However, the molecular mechanisms involved in gastric carcinogenesis are still not fully understood, making it difficult to design targeted therapeutic approaches.
The stem cell factor SOX2 regulates the tumorigenic potential in human gastric cancer cells.
Specimen part, Cell line, Treatment, Time
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 SamplesTo uncover molecular mechanisms specifically involved in the pathogenesis of colitis-associated colon cancer (CAC), we studied tumorigenesis in experimental models of CAC and sporadic CRC that mimic characteristics of human CRC. Using comparative whole genome expression profiling, we observed differential expression of epiregulin (Ereg) in mouse models of colitis-associated, but not sporadic colorectal cancer. Similarly, highly significant upregulation of Ereg expression was found in cohorts of patients with colitis-associated cancer in inflammatory bowel disease but not in sporadic colorectal cancer. Furthermore, tumor-associated fibroblasts were identified as major source of Ereg in colitis-associated neoplasias. Functional studies showed that Ereg-deficient mice, although more prone to colitis, are strongly protected from colitis-associated tumors, and data from serial endoscopic studies revealed that Ereg promotes growth rather than initiation of tumors.
Tumor fibroblast-derived epiregulin promotes growth of colitis-associated neoplasms through ERK.
Sex, Specimen part
View SamplesIdentifying sex differences in gene expression within the brain is critical for determining why multiple neurological and behavioral disorders differentially affect males and females. Several are more common or severe in males (e.g., autism and schizophrenia) or females (e.g., Alzheimer’s disease and depression). We analyzed transcriptomic data from the mouse hippocampus of six inbred strains (129S1/SvImJ, A/J, C57BL/6J, DBA/1J, DBA/2J and PWD/Ph), to provide a perspective on differences between male and female gene expression. Our data show that: 1) significant gene expression differences in males versus females varies substantially across the strains, 2) 12 genes exist that are differentially expressed across the inbred strains (termed core genes), and 3) there are >2,600 significantly differentially expressed genes (DEGs) among the strains (termed non-core genes). We found that DBA/2J uniquely has a substantial majority (89%) of DEGs that are more highly expressed in females than males; 129/SvImJ is the most strongly male-biased with a majority (69%) of DEGs that are more highly expressed in males. To gain insight into the sex-biased DEGs, we examined gene ontology, pathway and phenotype enrichment and found significant enrichment in phenotypes related to abnormal nervous system morphology and physiology, among others. In addition, several pathways are enriched significantly, including Alzheimer’s disease (AD), with 32 genes implicated in AD, 8 of which are male-biased. Three of the male-biased genes have been implicated in a neuroprotective role in AD. Our transcriptomic data provide new insight into understanding the possible genetic bases for sex-specific susceptibility and severity of brain disorders. Overall design: Hippocampal mRNA from adult males and females of six inbred strains of mice were analyzed by RNA sequencing of 3 biological replicates using an Illumina HiSeq 2500
Transcriptomic analysis of the hippocampus from six inbred strains of mice suggests a basis for sex-specific susceptibility and severity of neurological disorders.
Sex, Age, Specimen part, Cell line, Subject
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