Project description:The assembly of neural circuits involves multiple sequential steps such as the specification of cell types, their migration to proper brain locations, morphological and physiological differentiation, and the formation and maturation of synaptic connections. This intricate and often prolonged process is guided by elaborate genetic mechanisms that regulate each developmental event. Evidence from numerous systems suggests that each cell type, once specified, is endowed with a genetic program that directs its subsequent development. This cell intrinsic program unfolds in respond to, and is regulated by, extrinsic signals, including cell-cell and synaptic interactions. To a large extent, the execution of this genetic program is achieved by the expression of specific sets of genes that support distinct developmental processes. Therefore, a comprehensive analysis of the developmental progression of gene expression in synaptic partners of neurons may provide a basis for exploring the genetic mechanisms regulating circuit assembly. Here we examined the developmental gene expression profiles in well defined cell types in a stereotyped microcircuit of the cerebellar cortex. Manually sorted pure populations of Purkinje cells and Stellate/Basket cells, 3 biological replicates, from Gad67-GFP bac-transgenic (G42) mice were profiled during postnatal developmental stages P3, P7, P14, P21, P28, P35 and P56 using Affymetrix MOE430.2 expression array
Project description:We analyzed Purkinje cell transcriptome dynamics in the developing mouse cerebellum during the first three postnatal weeks, a key developmental period equivalent to the third trimester in human cerebellar development. Our study represents the first detailed analysis of developmental Purkinje cell transcriptomes and provides a valuable dataset for gene network analyses and biological questions on genes implicated in cerebellar and Purkinje cell development.
Project description:During the first 10 postnatal days of mouse development, Purkinje cells, neurons of the cerebellum, pass through different developmental processes of differentiation such as profound dendritic remodeling and growth, cell death and loss of their ability to regenerate their axons. To identify the genes involved in these different processes and in particular transcription factors, the gene expression patterns of murine cerebellar cortical area centered on Purkinje soma have been measured using Affymetrix microarrays at 5 different developmental stages (postnatal days P0, P3, P5, P7 and P10; 4 replicates = 4 independent measurements for each stage).
Project description:The signalling protein PKCγ is a major regulator of Purkinje cell development and synaptic function. We have shown previously that increased PKCγ activity impairs dendritic development of cerebellar Purkinje cells. Mutations in the protein kinase Cγ gene (PRKCG) cause spinocerebellar ataxia type 14 (SCA14). In a transgenic mouse model of SCA14 expressing the human S361G mutation, Purkinje cell dendritic development is impaired in cerebellar slice cultures similar to pharmacological activation of PKC. The mechanisms of PKCγ-driven inhibition of dendritic growth are still unclear. Using immunoprecipitation-coupled mass spectrometry analysis we have identified Collapsin Response Mediator Protein 2 (CRMP2) as a protein interacting with constitutive active PKCγ(S361G) and confirmed the interaction with the Duolink™ proximity ligation assay. We show that in cerebellar slice cultures from PKCγ(S361G)- mice, phosphorylation of CRMP2 at the known PKC target site Thr555 is increased in Purkinje cells confirming phosphorylation of CRMP2 by PKCγ. miRNA-mediated CRMP2 knockdown decreased Purkinje cell dendritic outgrowth in dissociated cerebellar cultures as did the transfection of CRMP2 mutants with a modified Thr555 site. In contrast, dendritic development was normal after wildtype CRMP2 overexpression. In a novel knock-in mouse expressing only the phospho-defective T555A-mutant CRMP2, Purkinje cell dendritic development was reduced in dissociated cultures. This reduction could be rescued by transfecting wildtype CRMP2 but only partially by the phospho-mimetic T555D-mutant. Our findings establish CRMP2 as an important target of PKCγ phosphorylation in Purkinje cells mediating its control of dendritic development. Dynamic regulation of CRMP2 phosphorylation via PKCγ is required for its correct function.
Project description:To model human cerebellar disease, we developed a novel, reproducible method to generate cerebellar Purkinje cells (PCs) from human pluripotent stem cells (hPSCs) that formed synapses when cultured with mouse granule cells and fired large calcium currents, measured with the genetically encoded calcium indicator jRGECO1a. Using translating ribosomal affinity purification (TRAP) to compare gene expression of differentiating hPSC-PCs to developing mouse PCs, we found hPSC-PCs to be most similar to late juvenile (P21) mouse PCs. Analysis of mouse PCs defined novel developmental expression patterns for mitochondria and autophagy associated genes, recapitulated in hPSC-PCs. We further identified species differences in gene expression and confirmed protein expression of CD40LG in native human, but not mouse PCs. This study provides a robust method for generating relatively mature hPSC-PCs with human specific gene expression and defines novel genetic features in comparison to the first comprehensive analysis of global gene expression patterns of postnatal mouse PC development.
Project description:To model human cerebellar disease, we developed a novel, reproducible method to generate cerebellar Purkinje cells (PCs) from human pluripotent stem cells (hPSCs) that formed synapses when cultured with mouse granule cells and fired large calcium currents, measured with the genetically encoded calcium indicator jRGECO1a. Using translating ribosomal affinity purification (TRAP) to compare gene expression of differentiating hPSC-PCs to developing mouse PCs, we found hPSC-PCs to be most similar to late juvenile (P21) mouse PCs. Analysis of mouse PCs defined novel developmental expression patterns for mitochondria and autophagy associated genes, recapitulated in hPSC-PCs. We further identified species differences in gene expression and confirmed protein expression of CD40LG in native human, but not mouse PCs. This study provides a robust method for generating relatively mature hPSC-PCs with human specific gene expression and defines novel genetic features in comparison to the first comprehensive analysis of global gene expression patterns of postnatal mouse PC development.
Project description:To model human cerebellar disease, we developed a novel, reproducible method to generate cerebellar Purkinje cells (PCs) from human pluripotent stem cells (hPSCs) that formed synapses when cultured with mouse granule cells and fired large calcium currents, measured with the genetically encoded calcium indicator jRGECO1a. Using translating ribosomal affinity purification (TRAP) to compare gene expression of differentiating hPSC-PCs to developing mouse PCs, we found hPSC-PCs to be most similar to late juvenile (P21) mouse PCs. Analysis of mouse PCs defined novel developmental expression patterns for mitochondria and autophagy associated genes, recapitulated in hPSC-PCs. We further identified species differences in gene expression and confirmed protein expression of CD40LG in native human, but not mouse PCs. This study provides a robust method for generating relatively mature hPSC-PCs with human specific gene expression and defines novel genetic features in comparison to the first comprehensive analysis of global gene expression patterns of postnatal mouse PC development.
Project description:We performed gene-expression analysis of mouse cerebellar granule cell layer as compared to that of Purkinje cells. DNA microarray analysis detected genes in cerebellar granule cell layer, most of which are classified into functional molecule categories. Our comparative analysis between Purkinje cells and the granule cell layer showed that the characteristic expression pattern in Purkinje cells was particularly represented by M-bM-^@M-^\the neural communication systemM-bM-^@M-^] components. Pukinje cells and granule cell layer of the mouse cerebellum were collected by laser microdissection for RNA extraction and hybridization on Affymetrix microarrays.
Project description:In this study, we identified active enhancers in the mouse cerebellum at embryonic and postnatal stages establishing the first catalog of enhancers active during embryonic cerebellum development. The majority of cerebellar enhancers have dynamic activity between embryonic and postnatal development. Cerebellar enhancers were enriched for neural transcription factor binding sites with temporally specific expression. Putative gene targets displayed spatially restricted expression patterns, indicating cell-type specific expression regulation. Functional analysis of target genes indicated that enhancers regulate processes spanning several developmental epochs such as specification, differentiation and maturation. We use these analyses to discover one novel regulator and one novel marker of cerebellar development: Bhlhe22 and Pax3, respectively. We identified an enrichment of de novo mutations and variants associated with autism spectrum disorder in cerebellar enhancers. Our study provides insight into the dynamics of gene expression regulation by enhancers in the developing brain and delivers a rich resource of novel gene-enhancer associations providing a basis for future in-depth studies in the cerebellum.
Project description:We performed gene-expression analysis of mouse cerebellar granule cell layer as compared to that of Purkinje cells. DNA microarray analysis detected genes in cerebellar granule cell layer, most of which are classified into functional molecule categories. Our comparative analysis between Purkinje cells and the granule cell layer showed that the characteristic expression pattern in Purkinje cells was particularly represented by “the neural communication system” components.