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Schilling K. Revisiting the development of cerebellar inhibitory interneurons in the light of single-cell genetic analyses. Histochem Cell Biol 2024; 161:5-27. [PMID: 37940705 PMCID: PMC10794478 DOI: 10.1007/s00418-023-02251-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2023] [Indexed: 11/10/2023]
Abstract
The present review aims to provide a short update of our understanding of the inhibitory interneurons of the cerebellum. While these cells constitute but a minority of all cerebellar neurons, their functional significance is increasingly being recognized. For one, inhibitory interneurons of the cerebellar cortex are now known to constitute a clearly more diverse group than their traditional grouping as stellate, basket, and Golgi cells suggests, and this diversity is now substantiated by single-cell genetic data. The past decade or so has also provided important information about interneurons in cerebellar nuclei. Significantly, developmental studies have revealed that the specification and formation of cerebellar inhibitory interneurons fundamentally differ from, say, the cortical interneurons, and define a mode of diversification critically dependent on spatiotemporally patterned external signals. Last, but not least, in the past years, dysfunction of cerebellar inhibitory interneurons could also be linked with clinically defined deficits. I hope that this review, however fragmentary, may stimulate interest and help focus research towards understanding the cerebellum.
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Affiliation(s)
- Karl Schilling
- Anatomisches Institut - Anatomie und Zellbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Nussallee 10, 53115, Bonn, Germany.
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van’t Sant LJ, White JJ, Hoeijmakers JHJ, Vermeij WP, Jaarsma D. In vivo 5-ethynyluridine (EU) labelling detects reduced transcription in Purkinje cell degeneration mouse mutants, but can itself induce neurodegeneration. Acta Neuropathol Commun 2021; 9:94. [PMID: 34020718 PMCID: PMC8139001 DOI: 10.1186/s40478-021-01200-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/12/2021] [Indexed: 12/20/2022] Open
Abstract
Fluorescent staining of newly transcribed RNA via metabolic labelling with 5-ethynyluridine (EU) and click chemistry enables visualisation of changes in transcription, such as in conditions of cellular stress. Here, we tested whether EU labelling can be used to examine transcription in vivo in mouse models of nervous system disorders. We show that injection of EU directly into the cerebellum results in reproducible labelling of newly transcribed RNA in cerebellar neurons and glia, with cell type-specific differences in relative labelling intensities, such as Purkinje cells exhibiting the highest levels. We also observed EU-labelling accumulating into cytoplasmic inclusions, indicating that EU, like other modified uridines, may introduce non-physiological properties in labelled RNAs. Additionally, we found that EU induces Purkinje cell degeneration nine days after EU injection, suggesting that EU incorporation not only results in abnormal RNA transcripts, but also eventually becomes neurotoxic in highly transcriptionally-active neurons. However, short post-injection intervals of EU labelling in both a Purkinje cell-specific DNA repair-deficient mouse model and a mouse model of spinocerebellar ataxia 1 revealed reduced transcription in Purkinje cells compared to controls. We combined EU labelling with immunohistology to correlate altered EU staining with pathological markers, such as genotoxic signalling factors. These data indicate that the EU-labelling method provided here can be used to identify changes in transcription in vivo in nervous system disease models.
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Developmental upregulation of an alternative form of pcp2 with reduced GDI activity. THE CEREBELLUM 2014; 13:207-14. [PMID: 24092530 PMCID: PMC3939015 DOI: 10.1007/s12311-013-0529-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The pcp2/L7 gene is characterized by its very cell type-specific expression restricted to cerebellar Purkinje cells and retinal bipolar neurons. Although remarkable progress as to the biochemical properties of the encoded protein has been made, knowledge on its physiological functions remains sparse. While characterizing a pcp2-driven transgenic strain, we observed the presence of a longer, so far unknown, pcp2 transcript. Different from another recently discovered splice variant, ret-pcp2, expression of this novel transcript is observed in bipolar as well as cerebellar Purkinje cells of mid-postnatal mice. The protein encoded by our novel variant appears to be less efficient in binding to Gα subunits compared to the original L7/pcp2 protein and it is also less inhibitory with respect to GTPγ binding. Its expression in the eye appears to be independent from eye opening in postnatal mice.
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Kratz A, Beguin P, Kaneko M, Chimura T, Suzuki AM, Matsunaga A, Kato S, Bertin N, Lassmann T, Vigot R, Carninci P, Plessy C, Launey T. Digital expression profiling of the compartmentalized translatome of Purkinje neurons. Genome Res 2014; 24:1396-410. [PMID: 24904046 PMCID: PMC4120092 DOI: 10.1101/gr.164095.113] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Underlying the complexity of the mammalian brain is its network of neuronal connections, but also the molecular networks of signaling pathways, protein interactions, and regulated gene expression within each individual neuron. The diversity and complexity of the spatially intermingled neurons pose a serious challenge to the identification and quantification of single neuron components. To address this challenge, we present a novel approach for the study of the ribosome-associated transcriptome-the translatome-from selected subcellular domains of specific neurons, and apply it to the Purkinje cells (PCs) in the rat cerebellum. We combined microdissection, translating ribosome affinity purification (TRAP) in nontransgenic animals, and quantitative nanoCAGE sequencing to obtain a snapshot of RNAs bound to cytoplasmic or rough endoplasmic reticulum (rER)-associated ribosomes in the PC and its dendrites. This allowed us to discover novel markers of PCs, to determine structural aspects of genes, to find hitherto uncharacterized transcripts, and to quantify biophysically relevant genes of membrane proteins controlling ion homeostasis and neuronal electrical activities.
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Affiliation(s)
- Anton Kratz
- RIKEN Center for Life Science Technologies, Division of Genomic Technologies, Yokohama, Kanagawa, 230-0045 Japan
| | - Pascal Beguin
- RIKEN Brain Science Institute, Launey Research Unit, Wako, Saitama, 351-0198 Japan
| | - Megumi Kaneko
- RIKEN Brain Science Institute, Launey Research Unit, Wako, Saitama, 351-0198 Japan
| | - Takahiko Chimura
- RIKEN Brain Science Institute, Launey Research Unit, Wako, Saitama, 351-0198 Japan
| | - Ana Maria Suzuki
- RIKEN Center for Life Science Technologies, Division of Genomic Technologies, Yokohama, Kanagawa, 230-0045 Japan
| | - Atsuko Matsunaga
- RIKEN Brain Science Institute, Launey Research Unit, Wako, Saitama, 351-0198 Japan
| | - Sachi Kato
- RIKEN Center for Life Science Technologies, Division of Genomic Technologies, Yokohama, Kanagawa, 230-0045 Japan
| | - Nicolas Bertin
- RIKEN Center for Life Science Technologies, Division of Genomic Technologies, Yokohama, Kanagawa, 230-0045 Japan
| | - Timo Lassmann
- RIKEN Center for Life Science Technologies, Division of Genomic Technologies, Yokohama, Kanagawa, 230-0045 Japan
| | - Réjan Vigot
- RIKEN Brain Science Institute, Launey Research Unit, Wako, Saitama, 351-0198 Japan
| | - Piero Carninci
- RIKEN Center for Life Science Technologies, Division of Genomic Technologies, Yokohama, Kanagawa, 230-0045 Japan
| | - Charles Plessy
- RIKEN Center for Life Science Technologies, Division of Genomic Technologies, Yokohama, Kanagawa, 230-0045 Japan;
| | - Thomas Launey
- RIKEN Brain Science Institute, Launey Research Unit, Wako, Saitama, 351-0198 Japan
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Swanger SA, Bassell GJ. Dendritic protein synthesis in the normal and diseased brain. Neuroscience 2012; 232:106-27. [PMID: 23262237 DOI: 10.1016/j.neuroscience.2012.12.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 11/21/2012] [Accepted: 12/01/2012] [Indexed: 01/25/2023]
Abstract
Synaptic activity is a spatially limited process that requires a precise, yet dynamic, complement of proteins within the synaptic micro-domain. The maintenance and regulation of these synaptic proteins is regulated, in part, by local mRNA translation in dendrites. Protein synthesis within the postsynaptic compartment allows neurons tight spatial and temporal control of synaptic protein expression, which is critical for proper functioning of synapses and neural circuits. In this review, we discuss the identity of proteins synthesized within dendrites, the receptor-mediated mechanisms regulating their synthesis, and the possible roles for these locally synthesized proteins. We also explore how our current understanding of dendritic protein synthesis in the hippocampus can be applied to new brain regions and to understanding the pathological mechanisms underlying varied neurological diseases.
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Affiliation(s)
- S A Swanger
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - G J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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Iscru E, Serinagaoglu Y, Schilling K, Tian J, Bowers-Kidder SL, Zhang R, Morgan JI, DeVries AC, Nelson RJ, Zhu MX, Oberdick J. Sensorimotor enhancement in mouse mutants lacking the Purkinje cell-specific Gi/o modulator, Pcp2(L7). Mol Cell Neurosci 2008; 40:62-75. [PMID: 18930827 DOI: 10.1016/j.mcn.2008.09.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Accepted: 09/10/2008] [Indexed: 11/15/2022] Open
Abstract
Pcp2(L7) is a GoLoco domain protein specifically and abundantly expressed in cerebellar Purkinje cells. It has been hypothesized to "tune" G(i/o)-coupled receptor modulation of physiological effectors, including the P-type Ca(2+) channel. We have analyzed a mouse mutant in which the Pcp2(L7) gene was inactivated and find significant anatomical, behavioral and electrophysiological changes. Anatomically, we observed mild cerebellar hypoplasia. Behaviorally, the mutants were altered in modalities atypical for a traditional cerebellar mutant, and oddly, all of these changes could be considered functional enhancements. This includes increased asymptotic performance in gross motor learning, increased rate of acquisition in tone-conditioned fear, and enhanced pre-pulse inhibition of the acoustic startle response. Electrophysiological analysis of Purkinje cells in the mutants reveals depression of the complex spike waveform that may underlie the behavioral changes. Based on these observations we suggest that the Pcp2(L7) protein acts as a sensorimotor damper that modulates time- and sense-dependent changes in motor responses.
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Affiliation(s)
- Emilia Iscru
- Center for Molecular Neurobiology, The Ohio State University, Columbus, OH, USA
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