Project description:Expression analysis was performed with in vitro cultured cerebellar granule neurons (CGNs) isolated from rat brain. The CGNs were culture for four weeks. Each sample was collected after interval of seven days. No treatment was given to any cultured neurons at any time point. The purpose of the experiment was to identify the genes differentially expressed during the senescence of CGNs. The experiment is useful in revealing the senescence associated genetic markers in neurons.
Project description:To establish a new model system with which to study cerebellar granule lienage development and disease, human hbNES cells were differentiated to cerebellar granule neurons over a 56 day period.
Project description:To establish a new model system with which to study cerebellar granule lienage development and disease, human hbNES cells were differentiated to cerebellar granule neurons over a 56 day period.
Project description:To establish a new model system with which to study cerebellar granule lienage development and disease, human hbNES cells were differentiated to cerebellar granule neurons over a 56 day period.
Project description:Transcriptome analysis of mRNA samples purified from developing cerebellar granule cells and ES cell-derived granule cells using translating ribosome affinity purification (TRAP) method. Although mechanisms underlying early steps in cerebellar development are known, evidence is lacking on genetic and epigenetic changes during the establishment of the synaptic circuitry. Using metagene analysis, we report pivotal changes in multiple reactomes of epigenetic pathway genes in cerebellar granule cells (GCs) during circuit formation. During this stage, Tet genes are up-regulated and vitamin C activation of Tet enzymes increases the levels of 5-hydroxymethylcytosine (5hmC) at exon start sites of up-regulated genes, notably axon guidance genes and ion channel genes. Knockdown of Tet1 and Tet3 by RNA interference in ex vivo cerebellar slice cultures inhibits dendritic arborization of developing GCs, a critical step in circuit formation. These findings demonstrate a role for Tet genes and chromatin remodeling genes in the formation of cerebellar circuitry. We analyzed gene expression of cerebellar granule cells and ES cell-derived granule cells using the Affymetrix mouse gene 1.0 ST platform. Array data was processed by metagene analysis which was developed by the Broad Institute.
Project description:The cerebellum is a brain structure involved in motor and cognitive functions. The development of the cerebellar cortex (the external part of the cerebellum) is under the control of numerous factors. Among these factors, neuropeptides including PACAP or somatostatin modulate the survival, migration and/or differentiation of cerebellar granule cells. Interestingly, such peptides contributing to cerebellar ontogenesis usually exhibit a specific transient expression profile with a low abundance at birth, a high expression level during the developmental processes, which take place within the first two postnatal weeks in rodents, and a gradual decline toward adulthood. Thus, to identify new peptides transiently expressed in the cerebellum during development, rat cerebella were sampled from birth to adulthood, and analyzed by a semi-quantitative peptidomic approach. A total of 33 peptides were found to be expressed in the cerebellum. Among these 33 peptides, 8 had a clear differential expression pattern during development, 4 of them i.e. cerebellin 2, nociceptin, somatostatin and VGF [353-372], exhibiting a high expression level during the first two postnatal weeks followed by a significative decrease at adulthood. A focus by a genomic approach on nociceptin, confirmed that the precursor mRNA is transiently expressed during the first week of life in granule neurons within the internal granule cell layer of the cerebellum, and showed that the nociceptin receptor is also actively expressed between P8 and P16 by the same neurons. Finally, functional studies revealed a new role for nociceptin, acting as a neurotrophic peptide able to promote the survival and differentiation of developing cerebellar granule neurons.
Project description:It is generally believed that cerebellar granule neurons originate exclusively from granule neuron precursors (GNPs) in the external germinal layer (EGL). Here we identify a rare population of neuronal progenitors in the developing cerebellum that expresses Nestin. Although Nestin is widely considered a marker for multipotent stem cells, these Nestin-expressing progenitors (NEPs) are committed to the granule neuron lineage. Unlike conventional GNPs, which reside in the outer EGL and proliferate extensively, NEPs reside in the deep part of the EGL and are quiescent. Expression profiling reveals that NEPs are distinct from GNPs, and in particular, express markedly reduced levels of genes associated with DNA repair. Consistent with this, upon aberrant activation of Sonic hedgehog (Shh) signaling, NEPs exhibit more severe genomic instability and give rise to tumors more efficiently than GNPs. These studies identify a novel progenitor for cerebellar granule neurons and a novel cell of origin for medulloblastoma. 4 samples of Nestin expressing progenitors (NEPs), 4 samples of Math1 positive cells (GNPs) and 3 samples of Neural stem cells (CD133+ NSCs) were used for microarray analysis to determine the distinct genetic profile of NEPs. 4 samples of NEP-derived tumor and 4 samples of GNP-derived tumor were used to determine the similarity of those tumors by microarray analysis.