Striatal medium spiny neurons (MSN) are critically involved in motor control, and their degeneration is a principal component of Huntingtons disease. We find that the transcription factor Ctip2 (also known as Bcl11b) is central to MSN differentiation and striatal development. Within the striatum, it is expressed by all MSN, while it is excluded from essentially all striatal interneurons. In the absence of Ctip2, MSN do not fully differentiate, as demonstrated by dramatically reduced expression of a large number of MSN markers, including DARPP-32, FOXP1, Chrm4, Reelin, MOR1, GluR1, and Plexin-D1. Furthermore, MSN fail to aggregate into patches, resulting in severely disrupted patch-matrix organization within the striatum. Finally, heterotopic cellular aggregates invade the Ctip2-/- striatum suggesting a failure by MSN to repel these cells in the absence of Ctip2. In order to investigate the molecular mechanisms that underlie Ctip2-dependent differentiation of MSN and that underlie the patch-matrix disorganization in the mutant striatum, we directly compared gene expression between wild type and mutant striatum at P0. Because CTIP2-expressing MSN constitute 90-95% of the neurons within the striatum, we reasoned that we should be able to detect changes in medium spiny neuron gene expression in Ctip2 null mutants. We microdissected out small regions of striatum at matched locations in wild type and Ctip2-/- mutant littermates at P0 and investigated gene expression with Affymetrix microarrays. We selected the 153 most significant genes and further analyzed them to identify a smaller set of genes of potentially high biological relevance. In order to verify the microarray data and define the distribution of the identified genes in the striatum, we performed in situ hybridization or immunohistochemistry for 12 selected genes: Plexin-D1, Ngef, Nectin-3, Kcnip2, Pcp4L1, Neto1, Basonuclin 2, Fidgetin, Semaphorin 3e, Secretagogin, Unc5d, and Neurotensin. We find that all these genes are either specifically downregulated (Plexin-D1, Ngef, Nectin-3 Kcnip2, Pcp4L1, Neto1), or upregulated (Basonuclin 2, Fidgetin, Semaphorin 3e, Secretagogin, Unc5d, Neurotensin), in the Ctip2-/- striatum, confirming and extending the microarray results. Together, these data indicate that Ctip2 is a critical regulator of MSN differentiation, striatal patch development, and the establishment of the cellular architecture of the striatum.
Ctip2 controls the differentiation of medium spiny neurons and the establishment of the cellular architecture of the striatum.
No sample metadata fields
View SamplesCortical GABAergic interneurons constitute a highly diverse population of inhibitory neurons that are key regulators of cortical microcircuit function. An important and heterogeneous group of cortical interneurons specifically expresses the serotonin receptor 3A (5-HT3AR) but how this diversity emerges during development is poorly understood. Here we use single-cell transcriptomics to identify gene expression patterns operating in Htr3a-GFP+ interneurons during early steps of cortical circuit assembly. We identify 3 main molecular types of Htr3a-GFP+ interneurons, each displaying distinct developmental dynamics of gene expression. The transcription factor Meis2 is specifically enriched in a type of Htr3a-GFP+ interneurons spatially confined to the cortical white matter. These MEIS2 expressing interneurons appear to originate from a restricted region located at the embryonic pallial-subpallial boundary. Overall, this study identifies MEIS2 as a subclass-specific marker for 5-HT3AR-containing interstitial interneurons and demonstrates that the transcriptional and anatomical parcellation of cortical interneurons is developmentally coupled. Overall design: Single cell transcriptomics of cortical interneurons FACS sorted according to GFP-Htr3a+. Acquired from mouse brains of 3 different developmental ages: E18, P2, P5
Transcriptomic and anatomic parcellation of 5-HT<sub>3A</sub>R expressing cortical interneuron subtypes revealed by single-cell RNA sequencing.
Subject
View SamplesDuring cortical development, distinct subtypes of glutamatergic neurons are sequentially born and differentiate from dynamic populations of progenitors. How progenitors and their daughter cells are temporally patterned remains unknown. Here, we trace the transcriptional trajectories of successive generations of apical progenitors (APs) and isochronic cohorts of their daughter neurons in the developing mouse neocortex using high temporal resolution parallel single-cell RNA sequencing. We identify and functionally characterize a core set of evolutionarily-conserved temporally patterned genes which drive APs from internally-driven states to more exteroceptive states, revealing a progressively increasing role for extracellular signals as corticogenesis unfolds. These embryonic age-dependent AP molecular states are reflected in their neuronal progeny as successive ground states, onto which essentially conserved early post-mitotic differentiation programs are applied. Thus, temporally unfolding molecular birthmarks present in progenitors act in their post-mitotic progeny as seeds for adult neuronal diversity. Overall design: Investigation of the transcriptional dynamics in time-locked cohorts of cortical cells across embryonic neurogenesis. Flashtag is injected at 4 ages (E12, E13, E14, E15), and cells collected 1H, 24H, 96H after birth (= a total of 12 conditions) and analyzed by single cell transcriptomics.
Temporal patterning of apical progenitors and their daughter neurons in the developing neocortex.
Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
miR-182 Modulates Myocardial Hypertrophic Response Induced by Angiogenesis in Heart.
Age
View SamplesAngiogenesis induced by placental growth factor (PlGF) in heart promotes myocardial hypertrophy through the paracrine action of endothelium-derived nitric oxide which triggers the degradation of RGS4 and subsequent the activation of Akt/mTORC1 pathway in cardiomyocytes. However, whether alterations in miRNAs contribute to the development of hypertrophy is largely undetermined.
miR-182 Modulates Myocardial Hypertrophic Response Induced by Angiogenesis in Heart.
Age
View SamplesIntestinal epithelial stem cells (ISCs) are the focus of recent intense study. Current in vitro models rely on supplementation with the Wnt agonist R-spondin1 to support robust growth, ISC self-renewal, and differentiation. Intestinal subepithelial myofibroblasts (ISEMFs) are important supportive cells within the ISC niche. We hypothesized that co-culture with ISEMF enhances the growth of ISCs in vitro and allows for their successful in vivo implantation and engraftment. ISC-containing small intestinal crypts, FACS-sorted single ISCs, and ISEMFs were procured from C57BL/6 mice. Crypts and single ISCs were grown in vitro into enteroids, in the presence or absence of ISEMFs. ISEMFs enhanced the growth of intestinal epithelium in vitro in a proximity-dependent fashion, with co-cultures giving rise to larger enteroids than monocultures. Co-culture of ISCs with supportive ISEMFs relinquished the requirement of exogenous R-spondin1 to sustain long-term growth and differentiation of ISCs. Mono- and co-cultures were implanted subcutaneously in syngeneic mice. Co-culture with ISEMFs proved necessary for successful in vivo engraftment and proliferation of enteroids; implants without ISEMFs did not survive. ISEMF whole transcriptome sequencing and qPCR demonstrated high expression of specific R-spondins, well-described Wnt agonists that supports ISC growth. Specific non-supportive ISEMF populations had reduced expression of R-spondins. The addition of ISEMFs in intestinal epithelial culture therefore recapitulates a critical element of the intestinal stem cell niche and allows for its experimental interrogation and biodesign-driven manipulation. Overall design: Two samples of intestinal subepithelial myofibroblasts were used in this study.
Intestinal subepithelial myofibroblasts support the growth of intestinal epithelial stem cells.
No sample metadata fields
View SamplesPilocytic astrocytomas (PA) are the most common brain tumor in pediatric patients and can cause significant morbidity, including chronic neurological deficiencies. They are characterized by activating alterations in the mitogen-activated protein kinase (MAPK) pathway, but little else is known about their development. To further define their molecular development, we analysed the global DNA methylation profiles of 61 PAs and 6 normal cerebellum samples and integrated this data with transcriptome profiling. These data revealed two subgroups of PA that separate according to tumor location (infratentorial versus supratentorial), and identified key neural developmental genes that are differentially methylated between the two groups. Significant expression differences were identified for the majority of differentially methylated genes, and these were unexpectedly associated with a strong positive correlation between methylation and expression. We also identified a large number of differentially methylated/expressed genes between cerebellar PAs and normal cerebellum, which included additional developmental genes.
Differential expression and methylation of brain developmental genes define location-specific subsets of pilocytic astrocytoma.
Sex, Specimen part
View SamplesWe profiled the transcriptome of cardiomyocytes from hiPSCs throughout differentiation and at a single cell level to identify subpopulations. We further studied on the transcription factors NR2F2, TBX5, and HEY2 in these subpopulations. Overall design: Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) have become a powerful tool for human disease modeling and therapeutic testing. However, their use remains limited by their immaturity and heterogeneity. To characterize the source of this heterogeneity, we performed bulk RNA-seq on hiPSCs undergoing differentiation into cardiomyocytes over an extended time course followed by single-cell RNA-seq at a later time point (day 30). These analyses identified novel single-cell populations, characterized by the distinct or overlapping expression of TBX5, NR2F2, HEY2, ISL1, JARID2, and HOPX transcription factors. Analysis of RNA-seq data from hiPSC-CMs both during differentiation in vitro and from human heart tissues suggests these transcription factors underlie physiologically distinct lineages. Using CRISPR genome editing and ChIP-seq, in conjunction with patch clamp, calcium imaging, CYTOF, and single-cell Western analysis, we now demonstrate that these transcription factors play an essential role in specification of early atrial (NR2F2) and late ventricular (HEY2) cardiomyocytes. We RNA-sequenced NR2F2, TBX5, HEY2 gene edited lines as well as day 30 hiPSC-CMs overexpressing NR2F2, TBX5, and HEY2. These new targets, sequencing data, and methods provide a platform for improved investigation of in vitro cardiac heterogeneity.
Defining human cardiac transcription factor hierarchies using integrated single-cell heterogeneity analysis.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Functional and evolutionary significance of human microRNA seed region mutations.
Cell line
View SamplesMicroRNAs (miRNAs) are small non-coding RNAs that play a central role in the regulation of gene expression at the post transcriptional and/or translational level thus impacting various biological processes. Dysregulation of miRNAs could affect processes associated with progression of a variety of diseases including cancer. Majority of miRNA targeting in animals involves a 7-nt seed region mapping to positions 2-8 at the molecules 5' end. The importance of this 7 nt sequence to miRNA function is evidenced by the fact that the seed region sequence of many miRNAs is highly conserved within and between species. In this study, we computationally and experimentally explore the functional significance of sequence variation within the seed region of human miRNAs. Our results indicate that change of a single nt within the 7-nt seed region changes the spectrum of targeted mRNAs significantly meanwhile further nt changes have little to no additional effect. This high functional cost of even a single nucleotide change within the seed region of miRNAs explains why the seed sequence is highly conserved among many miRNA families both within and between species and could help clarify the likely mechanisms underlying the evolution of miRNA regulatory control.
Functional and evolutionary significance of human microRNA seed region mutations.
Cell line
View Samples