Neuronal histone H3-lysine 4 methylation landscapes are defined by sharp peaks at gene promoters and other cis-regulatory sequences, but molecular and cellular phenotypes after neuron-specific deletion of H3K4 methyl-regulators remain largely unexplored. We report that neuronal ablation of the H3K4-specific methyltransferase, Kmt2a/Mixed-lineage leukemia 1 (Mll1), in mouse postnatal forebrain and adult prefrontal cortex (PFC) is associated with increased anxiety and robust cognitive deficits without locomotor dysfunction. In contrast, only mild behavioral phenotypes were observed after ablation of the Mll1 ortholog Kmt2b/Mll2 in PFC. Impaired working memory after Kmt2a/Mll1 ablation in PFC neurons was associated with loss of training-induced transient waves of Arc immediate early gene expression critical for synaptic plasticity. Medial prefrontal layer V pyramidal neurons, a major output relay of the cortex, demonstrated severely impaired synaptic facilitation and temporal summation, two forms of short-term plasticity essential for working memory. Chromatin immunoprecipitation followed by deep sequencing in Mll1-deficient cortical neurons revealed downregulated expression and loss of the transcriptional mark, trimethyl-H3K4, at <50 loci, including the homeodomain transcription factor Meis2. Small RNA-mediated Meis2 knockdown in PFC was associated with working memory defects similar to those elicited by Mll1 deletion. Therefore, mature prefrontal neurons critically depend on maintenance of Mll1-regulated H3K4 methylation at a subset of genes with an essential role in cognition and emotion.
Neuronal Kmt2a/Mll1 histone methyltransferase is essential for prefrontal synaptic plasticity and working memory.
Sex, Specimen part
View SamplesReactive gliosis is a complex process that involves profound changes in gene expression. We used microarray to indentify differentially expressed genes and to investigate the molecular mechanisms of reactive gliosis in optic nerve head in response to optic nerve crush injury.
The Time Course of Gene Expression during Reactive Gliosis in the Optic Nerve.
Sex, Specimen part
View SamplesReactive astrocytes are typically studied in models that cause irreversible mechanical damage to axons, neuronal cell bodies, and glia. We evaluated the response of astrocytes in the optic nerve head to a subtle injury induced by a brief, mild elevation of the intraocular pressure. Astrocytes demonstrated reactive remodeling showing hypertrophy, process retraction and simplification of their shape.
Reversible reactivity by optic nerve astrocytes.
Sex
View SamplesCD133 (Prominin1) is pentaspan transmembrane glycoprotein expressed in several stem cell populations and cancers. Reactivity with an antibody (AC133) to a glycoslyated form of CD133 has been widely used for the enrichment of cells with tumor initiating activity in xenograph transplantation assays. We have found by fluorescence-activated cell sorting that increased AC133 reactivity in human embryonic stem cells, colon cancer and melanoma cells is correlated with increased DNA content and reciprocally, that the least reactive cells are in the G1/G0 portion of the cell cycle. Continued cultivation of cells sorted on the basis of high and low AC133 reactivity results in a normalization of the cell reactivity profiles indicating that cells with low AC133 reactivity can generate highly reactive cells as they resume proliferation. The association of AC133 with actively cycling cells may contribute to the basis for enrichment for tumor initiating activity.
Cell cycle-dependent variation of a CD133 epitope in human embryonic stem cell, colon cancer, and melanoma cell lines.
No sample metadata fields
View SamplesMicroRNAs (miRNA) are small, non-coding RNAs mediating post-transcriptional regulation of gene expression. miRNAs have recently been implicated in hippocampus-dependent functions such as learning and memory, although the roles of individual miRNAs in these processes remain largely unknown. Here, we achieved stable inhibition using AAV-delivered miRNA sponges of individual, highly expressed and brain-enriched miRNAs; miR-124, miR-9 and miR-34, in hippocampal neurons. Molecular and cognitive studies revealed a role for miR-124 in learning and memory. Inhibition of miR-124 resulted in an enhanced spatial learning and working memory capacity, potentially through altered levels of genes linked to synaptic plasticity and neuronal transmission. In contrast, inhibition of miR-9 or miR-34 led to a decreased capacity of spatial learning and of reference memory, respectively. On a molecular level, miR-9 inhibition resulted in altered expression of genes related to cell adhesion, endocytosis and cell death, while miR-34 inhibition caused transcriptome changes linked to neuroactive ligand-receptor transduction and cell communication. In summary, this study establishes distinct roles for individual miRNAs in hippocampal function. Overall design: Three RNA samples containing bilateral entire hippocampi from three different mice, per group. Group 1 were injected with vector containing GFP and a miR34sp/miR9sp and the other group were subjected to a vector expressing GFP only.
Distinct cognitive effects and underlying transcriptome changes upon inhibition of individual miRNAs in hippocampal neurons.
No sample metadata fields
View SamplesCells with slow proliferation kinetics that retain the nuclear label over long time periods – the label-retaining cells (LRCs) – represent multipotent stem cells in a number of adult tissues. Since the identity of liver LRCs (LLRCs) had remained elusive we utilized a genetic approach to reveal LLRCs in normal non-injured livers and characterized their regenerative properties in vivo and in culture. We found that LLRCs were located in biliary vessels and participated in the regeneration of biliary but not hepatocyte injury. In culture experiments the sorted LLRCs displayed an enhanced self-renewal capacity but a unipotent biliary differentiation potential. Transcriptome analysis revealed a unique set of tumorigenesis- and nervous system-related genes upregulated in LLRCs when compared to non-LRC cholangiocytes. We conclude that the LLRCs established during the normal morphogenesis of the liver do not represent a multipotent primitive somatic stem cell population but act as unipotent biliary progenitor cells. Overall design: Transcriptome comparison of label-retaining biliary epithelial cells and non-label-retaining biliary epithelial cells (cells with GFP expression were compared to the cells without GFP). Illumina HiSeq 2000 was used to analyze 8 RNA samples from 4 mice.
A label-retaining but unipotent cell population resides in biliary compartment of mammalian liver.
Subject
View SamplesWe sequenced mRNA from FACS purified hair follicle bulge stem cells from 21 d old control and ILK-deficient mice, 3 biological replicates each Overall design: Examination of mRNA levels in control and ILK-deficient hair follicle bulge stem cells
Integrin-linked kinase regulates the niche of quiescent epidermal stem cells.
No sample metadata fields
View SamplesWe sought to investigate the scope of cellular and molecular changes within a mouse's olfactory system as a function of its exposure to odors emitted from members of the opposite sex. To this end, we housed mice either separated from members of the opposite sex (sex-separated) or together with members of the opposite sex (sex-combined) until six months of age and then profiled transcript levels within the main olfactory epithelium (MOE), vomeronasal organ (VNO), and olfactory bulb (OB) of the mice via RNA-seq. For each tissue type, we then analyzed gene expression differences between sex-separated males and sex-separated females (SM v SF), sex-combined males and sex-combined females (CM v CF), sex-separated females and sex-combined females (SF v CF), and sex-separated males and sex-combined males (SM v CM). Within both the MOE and VNO, we observed significantly more numerous gene expression differences between males and females when mice were sex-separated as compared to sex-combined. Chemoreceptors were highly enriched among the genes differentially expressed between males and females in sex-separated conditions, and these expression differences were found to reflect differences in the abundance of the corresponding sensory neurons. Overall design: For each combination of tissue (MOE, VNO, OB), sex (F, M), and condition (sex-separated [S], sex-combined [C]), we generated three biological replicate samples of RNA, each of which contained equal quantities of RNA from two different mice. This resulted in a total of 36 samples.
Sex separation induces differences in the olfactory sensory receptor repertoires of male and female mice.
Sex, Age, Cell line, Subject
View SamplesMicroarray profiling using the Affymetrix GeneChip Human Genome U133 plus 2.0 arrays was performed to comprehensively determine global changes in transcript levels in bronchial epithelial cells following elastase treatment. Elastase caused a significant change in expression (P < 0.05, fold change 1.5) of 364 transcripts corresponding to 348 genes. Elastase affected the expression of signaling molecules including chemokines, cytokines, and receptors, as well as components of the spliceosome, transcription machinery, cell cycle and ubiquitin-mediated proteolysis.
Potent elastase inhibitors from cyanobacteria: structural basis and mechanisms mediating cytoprotective and anti-inflammatory effects in bronchial epithelial cells.
Specimen part, Treatment
View SamplesWe established a neuron-specific Argonaute2:GFP-RNA immunoprecipitation followed by high throughput sequencing (AGO2-RIP-seq) to analyse the regulatory role of miRNAs in mouse hippocampal neurons. Using this technique, we identified more than two thousand miRNA target genes in hippocampal neurons, regulating essential neuronal features such as axon guidance and transcription. Furthermore, we found that stable inhibition of the highly expressed miR-124 in hippocampal neurons led to significant changes in the AGO2 binding of target mRNAs, resulting in subsequent upregulation of numerous miRNA target genes. Our data suggest that target redundancies are common among microRNA families. Together, these findings greatly enhance our understanding of the mechanisms and dynamics through which miRNAs regulate their target genes in neurons. Overall design: Analysis of the miRNA targetome in hippocampal neurons after inhibition of 2 different miRNAs. AAV5 injections into the hippocampus of adult C57BL/6 mice producing either of the following under a synapsin promoter: GFP only (Samples beginning with ''GFP124…'' or ''GFP125…''), GFP-miR124sp (Samples beginning with ''miR124…''), GFP-miR125sp (Samples beginning with ''miR125…''), GFP-AGO2-miR292sponge (samples ending with ''…292''), GFP-AGO2-miR124sponge (samples ending with ''…124''), GFP-AGO2-miR125sponge (samples ending with ''…125''). All other samples were sham-injected.
Identification of the miRNA targetome in hippocampal neurons using RIP-seq.
No sample metadata fields
View Samples