Aberrant splicing is a hallmark of leukemias with mutations in splicing factor (SF)-encoding genes. Here we investigated its prevalence in pediatric B-cell acute lymphoblastic leukemias (B-ALL), where SFs are not mutated. By comparing them to normal pro-B cells, we found thousands of aberrant local splice variations (LSVs) per sample, with 279 LSVs in 241 genes present in every comparison. These genes were enriched in RNA processing pathways and encoded ~100 SFs, e.g. hnRNPA1. hnRNPA1 3'UTR was most pervasively misspliced, yielding the transcript subject to nonsense-mediated decay. Thus, we knocked it down in B-lymphoblastoid cells, identified 213 hnRNPA1-dependent splicing events, and defined the hnRNPA1 splicing signature in pediatric leukemias. One of its elements was DICER1, a known tumor suppressor gene; its LSVs involved the 5' UTR, suggestive of splicing as a mechanism of translational deregulation. Additionally, we searched for LSVs in other leukemia and lymphoma drivers and discovered 81 LSVs in 41 genes. 77 LSVs were confirmed using two large independent B-ALL RNA-seq datasets. In fact, the twenty most common B-ALL drivers showed higher prevalence of aberrant splicing than of somatic mutations. Thus, post-transcriptional deregulation of SF can drive widespread changes in B-ALL splicing and likely contribute to disease pathogenesis. Overall design: We profiled hnRNPA1 Ctrl and hnRNPA1 knockdown with 2 replicates each.
Aberrant splicing in B-cell acute lymphoblastic leukemia.
Specimen part, Cell line, Subject
View SamplesThe preoptic area (POA) of the hypothalamus is known to be crucial for sleep generation, but the spatial intermingling of sleep- and wake-promoting neurons makes it difficult to dissect the sleep control circuit. Here we identified a population of POA sleep-promoting neurons based on their projection target. Using a lentivirus for retrograde labeling with channelrhodopsin-2 (ChR2) followed by optogenetic manipulation and recording, we found that the POA GABAergic neurons projecting to the tuberomammillary nucleus (TMN) are both sleep active and sleep promoting. Cell type- and projection-specific rabies tracing revealed the presynaptic inputs to these neurons, including an amygdala GABAergic input that promotes wakefulness. Using single-cell RNA-seq, we identified several molecular markers for these neurons, and optogenetic activation of the POA neurons labeled by these markers confirmed their sleep-promoting effects. Together, these findings define a group of sleep-promoting neurons functionally, anatomically, and genetically. Overall design: Single-cell RNA-Seq of retrogradely-labeled POA neurons projecting to the tuberomammillary nucleus (TMN).
Identification of preoptic sleep neurons using retrograde labelling and gene profiling.
Subject
View SamplesDifferentially expressed genes along the paraxial mesoderm of 12 somite stage zebrafish embryos are identified
Spatiotemporal compartmentalization of key physiological processes during muscle precursor differentiation.
Specimen part
View SamplesWe previously isolated a subclone, MIN6 clone 4, from the parental MIN6 cells, that shows well-regulated insulin secretion in response to glucose, glybenclamide, and KCl, even after prolonged culture. To investigate the molecular mechanisms responsible for preserving GSIS in this subclone, we compared four groups of MIN6 cells: Pr-LP (parental MIN6, low passage number), Pr-HP (parental MIN6, high passage number), C4-LP (MIN6 clone 4, low passage number), and C4-HP (MIN6 clone 4, high passage number). Based on their capacity for GSIS, we designated the Pr-LP, C4-LP, and C4-HP cells as responder cells. In a DNA microarray analysis, we identified a group of genes with high expression in responder cells (responder genes), but extremely low expression in the Pr-HP cells.
Microarray analysis of novel candidate genes responsible for glucose-stimulated insulin secretion in mouse pancreatic β cell line MIN6.
Cell line
View SamplesThe Drosophila midgut is an ideal model system to study molecular mechanisms that interfere with the intestinal stem cells’ (ISCs) ability to function in tissue homeostasis. Due to the lack of a combination of molecular markers suitable to isolate ISCs from aged intestines, it has been a major challenge to study endogenous molecular changes of ISCs during aging. Our FACS-based approach using the esg-GAL4, UAS-GFP fly line allowed the isolation of a cell population enriched for ISCs from young and old midguts by their small size, little granularity and low GFP intensity. The isolated ISCs were subsequently used for RNA sequencing to identify endogenous changes in the transcriptome of young versus old ISCs. Overall design: Cell populations enriched for ISCs isolated from young (6-8 days old) and old (59-65 days old) midguts were sorted. Cells from three different batches of young and old midguts were subjected to Next Generation Sequencing using Illumina Genome Analyzer IIx.
Nipped-A regulates intestinal stem cell proliferation in <i>Drosophila</i>.
Age, Specimen part, Subject
View SamplesAcute liver injury is a critical life-threatening event. Common causes are infections, intoxication, and ischemic conditions. The cytokine Interleukin 22 (IL-22) has been implicated in this process. However, the role of IL-22 during acute liver damage is controversial, since both protective and pathogenic properties have been reported. IL-22 binding protein (IL-22BP, IL-22Ra2), a soluble endogenous inhibitor of IL-22, is able to regulate IL-22 activity, and thus might explain some of the controversial findings. Since the role of IL-22BP in liver injury is unknown, we used Il22bp deficient mice and mouse models for acute liver damage to address this point. We found that Il22bp deficient mice were more susceptible to ischemia- and acetaminophen- induced liver damage. Deficiency of Il22bp caused increased hepatic damage and delayed liver regeneration. Using an unbiased approach, we found that IL-22, if uncontrolled in Il22bp deficient mice, induced Cxcl10 expression by hepatocytes, thereby recruiting inflammatory CD11b+Ly6C+ monocytes into the liver upon liver damage. Accordingly, neutralization of Cxcl10 reversed the increased disease susceptibility of Il22bp deficient mice. In conclusion, our data suggest dual functions of IL-22 in acute liver damage, and highlight the need to control IL-22 activity via IL-22BP. Overall design: RNA sequencing of RNA isolated from liver tissue from mice that underwent liver reperfusion treatment (IR) or sham surgery, in triplicate for three genotypes (Wt, Il22-/- and Il22bp-/-).
A Protective Function of IL-22BP in Ischemia Reperfusion and Acetaminophen-Induced Liver Injury.
Specimen part, Treatment, Subject
View SamplesThe supraoptic nucleus (SON) of the hypothalamus is an important integrative brain structure that co-ordinates responses to perturbations in water balance and regulates maternal physiology through the release of the neuropeptide hormones vasopressin and oxytocin into the circulation. Both dehydration and lactation evoke a dramatic morphological remodelling of the SON, a process known as function-related plasticity. We hypothesise that some of the changes seen in SON remodelling are mediated by differential gene expression, and have thus used microarrays to document global changes in transcript abundance that accompany chronic dehydration in female rats, and in lactation. In situ hydridisation analysis has confirmed the differential expression of 3 of these genes, namely Tumour necrosis factor induced protein 6, Gonadotrophin inducible transcription factor 1 and Ornithine decarboxylase antizyme inhibitor 1. Comparison of differential gene expression patterns in male and female rats subjected to dehydration and in lactating rats has enabled the identification of common elements that are significantly enriched in gene classes with particular functions. Two of these are related to the requirement for increased protein synthesis and hormone delivery in the physiologically stimulated SON (translation initiation factor activity and endoplasmic reticulum-Golgi intermediate compartment respectively), whilst others are consistent with concept of SON morphological plasticity (collagen fibril organisation, extracellular matrix organization and biogenesis, extracellular structure organization and biogenesis and homophilic cell adhesion). We suggest that the genes co-ordinately regulated in the SON as a consequence of dehydration and lactation form a network that mediates the plastic processes operational in the physiologically activated SON.
Transcriptomic analysis of the osmotic and reproductive remodeling of the female rat supraoptic nucleus.
Sex, Specimen part, Treatment
View SamplesThere is an evident, unmet need to develop a commercially available in vitro system that can model inflammatory states of the liver and predict immune-mediated hepatotoxicity of drugs and xenobiotics taken under inflamed conditions. Hepatocyte-Kupffer cell co-cultures can model inflammation-mediated hepatotoxicity; however, Kupffer cell (KC) source remains an important bottleneck for the development of such models. Primary human Kupffer cells (PHKCs) are costly, limited in availability and exhibit donor variability. An alternative cell source for KCs has not been reported. Important paradigm shift from the classical dogma of adult blood-circulating monocyte-derived macrophages to intrahepatic precursor/fetal monocyte-derived macrophages has shed new light into the origin of KCs in vivo. Based on these recent findings, we report here, a novel method to generate human KCs in vitro from stem cells (hPSC-KCs) via fetal monocytes. hPSC-KCs expressed macrophage markers, CD11, CD14, CD68, CD163 and CD32 at gene and protein level and exhibited functional properties such as phagocytosis and Interleukin-6 and Tumor Necrosis Factor-4alpha production upon activation. Importantly, molecular signature, liver-macrophage specific CLEC-4F expression and cytokines production levels of hPSC-KCs were similar to PHKCs but different from non-liver macrophages. We used an inflammatory liver co-culture model to demonstrate that activated hPSC-KCs, but not non-liver macrophages, were able to recapitulate effects of PHKCs when stimulated with paradigm hepatotoxicants. hPSC-KCs developed in this study offer a renewable human cell source for liver-specific macrophages which can be used to develop in vitro systems for modelling the inflammatory state of the liver.
Generation of mature kupffer cells from human induced pluripotent stem cells.
Specimen part
View SamplesStem and progenitor cells are the critical units for tissue maintenance, regeneration, and repair. The activation of regenerative events in response to tissue injury has been correlated with mobilization of tissue-resident progenitor cells, which is functional to the wound healing process. However, until now there has been no evidence for the presence of cells with a healing capacity circulating in healthy conditions. We identified a rare cell population present in the peripheral blood of healthy mice that actively participates in tissue repair. These Circulating cells, with a Homing ability and involved in the Healing process (CH cells), were identified by an innovative flowcytometry strategy as small cells not expressing CD45 and lineage markers. Their transcriptome profile revealed that CH cells are unique and present a high expression of key pluripotency- and epiblast-associated genes. More importantly, CH-labeled cells derived from healthy Red Fluorescent Protein (RFP)-transgenic mice and systemically injected into syngeneic fractured wild-type mice migrated and engrafted in wounded tissues, ultimately differentiating into tissue-specific cells. Accordingly, the number of CH cells in the peripheral blood rapidly decreased following femoral fracture. These findings uncover the existence of constitutively circulating cells that may represent novel, accessible, and versatile effectors of therapeutic tissue regeneration.
Identification of a New Cell Population Constitutively Circulating in Healthy Conditions and Endowed with a Homing Ability Toward Injured Sites.
Sex, Specimen part
View SamplesTranscriptomic profiling of complex tissues by single-nucleus RNA-sequencing (snRNA-seq) affords some advantages over single-cell RNA-sequencing (scRNA-seq). snRNA-seq provides less biased cellular coverage, does not appear to suffer cell isolation-based transcriptional artifacts, and can be applied to archived frozen specimens. We used well-matched snRNA-seq and scRNA-seq datasets from mouse visual cortex to compare cell type detection. Although more transcripts are detected in individual whole cells (~11,000 genes) than nuclei (~7,000 genes), we demonstrate that closely related neuronal cell types can be similarly discriminated with both methods if intronic sequences are included in snRNA-seq analysis. We estimate that the nuclear proportion of total cellular mRNA varies from 20% to over 50% for large and small pyramidal neurons, respectively. Together, these results illustrate the high information content of nuclear RNA for characterization of cellular diversity in brain tissues. Overall design: scRNA-seq of 463 single nuclei and 463 matched single cells from mouse primary visual cortex (VISp) and 30 control samples. Note that single cell data respresents a small subset of VISp cells from GEO series GSE115746.
Single-nucleus and single-cell transcriptomes compared in matched cortical cell types.
Subject
View Samples