Reactive 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 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.
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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.
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View SamplesMicroRNAs (miRNAs) have been implicated in regulating multiple processes during brain development in various species. However, the function of miRNAs in human brain development remains largely unexplored. Here, we provide a comprehensive analysis of miRNA expression of regionalized neural progenitor cells derived from human embryonic stem cells and human fetal brain. We found mir-92b-3p and mir-130b-5p to be specifically associated with neural progenitors and several miRNAs that display both age-specific and region-specific expression patterns. Among these miRNAs, we identified miR-10 to be specifically expressed in the human hindbrain and spinal cord, while absent from rostral regions. We found that miR-10 regulates a large number of genes enriched for functions including transcription, actin cytoskeleton and ephrin receptor signaling. When overexpressed, miR-10 influences caudalization of human neural progenitors cells. Together, these data confirms a role for miRNAs in establishing different human neural progenitor populations. This data set also provides a comprehensive resource for future studies investigating the functional role of different miRNAs in human brain development. Overall design: Human embryonic stem cells (hESCs) were transduced with lentiviral vectors expressing either miR10a-GFP or miR10b-GFP. The expression of the vectors is Tet-regulated and they will only be expressed in the presence of Doxycycline. In order to detect direct targets of the miR10a and miR10b, we differentiated the trasduced hESCs for 14 days, and added doxycycline to only half of the groups - resulting in groups that are overexpressing miR10a or miR10b and some groups that are not overexpressing these miRNAs.
Comprehensive analysis of microRNA expression in regionalized human neural progenitor cells reveals microRNA-10 as a caudalizing factor.
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View SamplesThe aim of the study was to investigate the role of TGIF1 in MLL-AF9 transformed cells
TGIF1 is a negative regulator of MLL-rearranged acute myeloid leukemia.
Cell line
View SamplesSuccinate semialdehyde dehydrogenase (SSADH) deficiency is a rare autosomal recessive disorder effecting approximately 350 people around the world. Patients suffering from SSADH deficiency experience language acquisition failure, memory deficiencies, autism, increased aggressive behaviors, and seizures. There is a chemical buildup of both gamma-aminobutyric acid (GABA) and gamma-hydroxybutyric acid (GHB) in the neurological system of these patients. The Aldh5a1-/- knock out mouse model of SSADH deficiency shows the same chemical imbalances as the human disease, with additional fatal tonic-clonic seizures at three weeks of age. The elucidation of seizure causing pathways will facilitate treatment of seizure phenotypes in diseases with related epilepsy.
Expression profiling reveals multiple myelin alterations in murine succinate semialdehyde dehydrogenase deficiency.
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View SamplesIn this study, we use a conditional mouse model for Cebpa to investigate the significance of C/EBP in HSCs. The frequency of HSCs is unaltered following deletion of C/EBP, however, upon serial transplantations of either full BM or purified HSCs, the stem cells and stem cell activity is lost. This is not due to increased proliferation, but rather caused by a shift from quiescence to apoptosis with a resultant exhaustion of the stem cell pool. We identify direct C/EBP target genes by combining genome-wide C/EBP ChIP-seq analysis in stem and progenitor cells with gene expression data from HSC with and without C/EBP. Furthermore, we explore the impact of C/EBP on active and repressive histone modifications by doing functional genome-wide ChIP-seq analysis of H3K4Me3 and H3K27Me3 in stem and progenitor cells with and without C/EBP.
C/EBPα is required for long-term self-renewal and lineage priming of hematopoietic stem cells and for the maintenance of epigenetic configurations in multipotent progenitors.
Sex, Specimen part
View SamplesHere we show that in neural progenitor cells (NPCs) TRIM28 silences transcription of two groups of endogenous retroviruses (ERVs): IAP1 and MMERVK10C. Derepression of ERVs in Trim28-deficient NPCs was associated with a loss of H3K9me3 and resulted in transcriptional upregulation and reverse transcription. These findings demonstrate a unique dynamic transcriptional regulation of ERVs in NPCs. Overall design: Analysis of upregulation of ERVs in Trim28-deficient NPCs
TRIM28 represses transcription of endogenous retroviruses in neural progenitor cells.
Specimen part, Cell line, Subject
View SamplesRNA-seq and expression profile of WT and ZFP57 KO ES cells Overall design: RNA was extracted from both cell lines, PolyA RNA were extracted and RNA-seq was performed
In embryonic stem cells, ZFP57/KAP1 recognize a methylated hexanucleotide to affect chromatin and DNA methylation of imprinting control regions.
Specimen part, Subject
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