1
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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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2
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Butler DF, Skibo J, Traudt CM, Millen KJ. Neonatal subarachnoid hemorrhage disrupts multiple aspects of cerebellar development. Front Mol Neurosci 2023; 16:1161086. [PMID: 37187957 PMCID: PMC10175619 DOI: 10.3389/fnmol.2023.1161086] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 04/10/2023] [Indexed: 05/17/2023] Open
Abstract
Over the past decade, survival rates for extremely low gestational age neonates (ELGANs; <28 weeks gestation) has markedly improved. Unfortunately, a significant proportion of ELGANs will suffer from neurodevelopmental dysfunction. Cerebellar hemorrhagic injury (CHI) has been increasingly recognized in the ELGANs population and may contribute to neurologic dysfunction; however, the underlying mechanisms are poorly understood. To address this gap in knowledge, we developed a novel model of early isolated posterior fossa subarachnoid hemorrhage (SAH) in neonatal mice and investigated both acute and long-term effects. Following SAH on postnatal day 6 (P6), we found significant decreased levels of proliferation with the external granular layer (EGL), thinning of the EGL, decreased Purkinje cell (PC) density, and increased Bergmann glial (BG) fiber crossings at P8. At P42, CHI resulted in decreased PC density, decreased molecular layer interneuron (MLI) density, and increased BG fiber crossings. Results from both Rotarod and inverted screen assays did not demonstrate significant effects on motor strength or learning at P35-38. Treatment with the anti-inflammatory drug Ketoprofen did not significantly alter our findings after CHI, suggesting that treatment of neuro-inflammation does not provide significant neuroprotection post CHI. Further studies are required to fully elucidate the mechanisms through which CHI disrupts cerebellar developmental programming in order to develop therapeutic strategies for neuroprotection in ELGANs.
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Affiliation(s)
- David F. Butler
- Division of Pediatric Critical Care, Seattle Children's Hospital, University of Washington, Seattle, WA, United States
| | - Jonathan Skibo
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States
| | | | - Kathleen J. Millen
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States
- Department of Pediatrics, University of Washington Medical School, Seattle, WA, United States
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3
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Martín R, Suárez-Pinilla AS, García-Font N, Laguna-Luque ML, López-Ramos JC, Oset-Gasque MJ, Gruart A, Delgado-García JM, Torres M, Sánchez-Prieto J. The activation of mGluR4 rescues parallel fiber synaptic transmission and LTP, motor learning and social behavior in a mouse model of Fragile X Syndrome. Mol Autism 2023; 14:14. [PMID: 37029391 PMCID: PMC10082511 DOI: 10.1186/s13229-023-00547-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 04/03/2023] [Indexed: 04/09/2023] Open
Abstract
BACKGROUND Fragile X syndrome (FXS), the most common inherited intellectual disability, is caused by the loss of expression of the Fragile X Messenger Ribonucleoprotein (FMRP). FMRP is an RNA-binding protein that negatively regulates the expression of many postsynaptic as well as presynaptic proteins involved in action potential properties, calcium homeostasis and neurotransmitter release. FXS patients and mice lacking FMRP suffer from multiple behavioral alterations, including deficits in motor learning for which there is currently no specific treatment. METHODS We performed electron microscopy, whole-cell patch-clamp electrophysiology and behavioral experiments to characterise the synaptic mechanisms underlying the motor learning deficits observed in Fmr1KO mice and the therapeutic potential of positive allosteric modulator of mGluR4. RESULTS We found that enhanced synaptic vesicle docking of cerebellar parallel fiber to Purkinje cell Fmr1KO synapses was associated with enhanced asynchronous release, which not only prevents further potentiation, but it also compromises presynaptic parallel fiber long-term potentiation (PF-LTP) mediated by β adrenergic receptors. A reduction in extracellular Ca2+ concentration restored the readily releasable pool (RRP) size, basal synaptic transmission, β adrenergic receptor-mediated potentiation, and PF-LTP. Interestingly, VU 0155041, a selective positive allosteric modulator of mGluR4, also restored both the RRP size and PF-LTP in mice of either sex. Moreover, when injected into Fmr1KO male mice, VU 0155041 improved motor learning in skilled reaching, classical eyeblink conditioning and vestibuloocular reflex (VOR) tests, as well as the social behavior alterations of these mice. LIMITATIONS We cannot rule out that the activation of mGluR4s via systemic administration of VU0155041 can also affect other brain regions. Further studies are needed to stablish the effect of a specific activation of mGluR4 in cerebellar granule cells. CONCLUSIONS Our study shows that an increase in synaptic vesicles, SV, docking may cause the loss of PF-LTP and motor learning and social deficits of Fmr1KO mice and that the reversal of these changes by pharmacological activation of mGluR4 may offer therapeutic relief for motor learning and social deficits in FXS.
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Affiliation(s)
- Ricardo Martín
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense, Instituto Universitario de Investigación en Neuroquímica, 28040, Madrid, Spain.
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, 28040, Madrid, Spain.
- Departamento de Fisiología, Facultad de Medicina, Universidad Complutense, 28040, Madrid, Spain.
| | - Alberto Samuel Suárez-Pinilla
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense, Instituto Universitario de Investigación en Neuroquímica, 28040, Madrid, Spain
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, 28040, Madrid, Spain
| | - Nuria García-Font
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense, Instituto Universitario de Investigación en Neuroquímica, 28040, Madrid, Spain
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, 28040, Madrid, Spain
- Centre for Discovery Brain Sciences and Simon Initiative for Developing Brain, University of Edinburgh, Edinburgh, EH89JZ, UK
| | | | - Juan C López-Ramos
- Division de Neurociencias, Universidad Pablo de Olavide, 41013, Sevilla, Spain
| | - María Jesús Oset-Gasque
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, 28040, Madrid, Spain
- Departamento de Bioquímica, Facultad de Farmacia, Universidad Complutense, Instituto Universitario Investigación en Neuroquímica, 28040, Madrid, Spain
| | - Agnes Gruart
- Division de Neurociencias, Universidad Pablo de Olavide, 41013, Sevilla, Spain
| | | | - Magdalena Torres
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense, Instituto Universitario de Investigación en Neuroquímica, 28040, Madrid, Spain
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, 28040, Madrid, Spain
| | - José Sánchez-Prieto
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense, Instituto Universitario de Investigación en Neuroquímica, 28040, Madrid, Spain.
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, 28040, Madrid, Spain.
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Butler DF, Skibo J, Traudt CM, Millen KJ. Neonatal Subarachnoid Hemorrhage Disrupts Multiple Aspects of Cerebellar Development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.10.528048. [PMID: 36798230 PMCID: PMC9934646 DOI: 10.1101/2023.02.10.528048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Over the past decade, survival rates for extremely low gestational age neonates (ELGANs; <28 weeks gestation) has markedly improved. Unfortunately, a significant proportion of ELGANs will suffer from neurodevelopmental dysfunction. Cerebellar hemorrhagic injury (CHI) has been increasingly recognized in the ELGANs population and may contribute to neurologic dysfunction; however, the underlying mechanisms are poorly understood. To address this gap in knowledge, we developed a novel model of early isolated posterior fossa subarachnoid hemorrhage (SAH) in neonatal mice and investigated both acute and long-term effects. Following SAH on postnatal day 6 (P6), we found significant decreased levels of proliferation with the external granular layer (EGL), thinning of the EGL, decreased Purkinje cell (PC) density, and increased Bergmann glial (BG) fiber crossings at P8. At P42, CHI resulted in decreased PC density, decreased molecular layer interneuron (MLI) density, and increased BG fiber crossings. Results from both Rotarod and inverted screen assays did not demonstrate significant effects on motor strength or learning at P35-38. Treatment with the anti-inflammatory drug Ketoprofen did not significantly alter our findings after CHI, suggesting that treatment of neuro-inflammation does not provide significant neuroprotection post CHI. Further studies are required to fully elucidate the mechanisms through which CHI disrupts cerebellar developmental programming in order to develop therapeutic strategies for neuroprotection in ELGANs.
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5
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Dendritic Inhibition by Shh Signaling-Dependent Stellate Cell Pool Is Critical for Motor Learning. J Neurosci 2022; 42:5130-5143. [PMID: 35589396 PMCID: PMC9236294 DOI: 10.1523/jneurosci.2073-21.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 03/14/2022] [Accepted: 04/11/2022] [Indexed: 12/31/2022] Open
Abstract
Cerebellar inhibitory interneurons are important regulators of neural circuit activity for diverse motor and nonmotor functions. The molecular layer interneurons (MLIs), consisting of basket cells (BCs) and stellate cells (SCs), provide dendritic and somatic inhibitory synapses onto Purkinje cells, respectively. They are sequentially generated in an inside-out pattern from Pax2+ immature interneurons, which migrate from the prospective white matter to the ML of the cortex. However, little is known about how MLI subtype identities and pool sizes are determined, nor are their contributions to motor learning well understood. Here, we show that GABAergic progenitors fated to generate both BCs and SCs respond to the Sonic hedgehog (Shh) signal. Conditional abrogation of Shh signaling of either sex inhibited proliferation of GABAergic progenitors and reduced the number of Pax2+ cells, whereas persistent Shh pathway activation increased their numbers. These changes, however, did not affect early born BC numbers but selectively altered the SC pool size. Moreover, genetic depletion of GABAergic progenitors when BCs are actively generated also resulted in a specific reduction of SCs, suggesting that the specification of MLI subtypes is independent of Shh signaling and their birth order and likely occurs after Pax2+ cells settle into their laminar positions in an inside-out sequence. Mutant mice with reduced SC numbers displayed decreased dendritic inhibitory synapses and neurotransmission onto Purkinje cells, resulting in an impaired acquisition of eyeblink conditioning. These findings also reveal an essential role of Shh signaling-dependent SCs in regulating inhibitory dendritic synapses and motor learning.SIGNIFICANCE STATEMENT The cerebellar circuit that enables fine motor learning involves MLIs of BCs and SCs, which provide dendritic and somatic inhibitory synapses onto Purkinje cells. Little is known about how their identities and numbers are determined, nor are their specific contributions to motor learning well understood. We show that MLI subtypes are specified independent of Shh signaling and their birth orders but appear to occur in their terminal laminar positions according to the inside-out sequence. This finding challenges the current view that MLI subtypes are specified sequentially at the progenitor level. We also demonstrate that dendritic inhibition by Shh signaling-dependent SC pool is necessary for motor learning.
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Morphological pseudotime ordering and fate mapping reveal diversification of cerebellar inhibitory interneurons. Nat Commun 2022; 13:3433. [PMID: 35701402 PMCID: PMC9197879 DOI: 10.1038/s41467-022-30977-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 05/20/2022] [Indexed: 12/15/2022] Open
Abstract
Understanding how diverse neurons are assembled into circuits requires a framework for describing cell types and their developmental trajectories. Here we combine genetic fate-mapping, pseudotemporal profiling of morphogenesis, and dual morphology and RNA labeling to resolve the diversification of mouse cerebellar inhibitory interneurons. Molecular layer interneurons (MLIs) derive from a common progenitor population but comprise diverse dendritic-, somatic-, and axon initial segment-targeting interneurons. Using quantitative morphology from 79 mature MLIs, we identify two discrete morphological types and presence of extensive within-class heterogeneity. Pseudotime trajectory inference using 732 developmental morphologies indicate the emergence of distinct MLI types during migration, before reaching their final positions. By comparing MLI identities from morphological and transcriptomic signatures, we demonstrate the dissociation between these modalities and that subtype divergence can be resolved from axonal morphogenesis prior to marker gene expression. Our study illustrates the utility of applying single-cell methods to quantify morphology for defining neuronal diversification.
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7
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Fernández-Suárez D, Krapacher FA, Pietrajtis K, Andersson A, Kisiswa L, Carrier-Ruiz A, Diana MA, Ibáñez CF. Adult medial habenula neurons require GDNF receptor GFRα1 for synaptic stability and function. PLoS Biol 2021; 19:e3001350. [PMID: 34748545 PMCID: PMC8601618 DOI: 10.1371/journal.pbio.3001350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 11/18/2021] [Accepted: 10/05/2021] [Indexed: 11/18/2022] Open
Abstract
The medial habenula (mHb) is an understudied small brain nucleus linking forebrain and midbrain structures controlling anxiety and fear behaviors. The mechanisms that maintain the structural and functional integrity of mHb neurons and their synapses remain unknown. Using spatiotemporally controlled Cre-mediated recombination in adult mice, we found that the glial cell-derived neurotrophic factor receptor alpha 1 (GFRα1) is required in adult mHb neurons for synaptic stability and function. mHb neurons express some of the highest levels of GFRα1 in the mouse brain, and acute ablation of GFRα1 results in loss of septohabenular and habenulointerpeduncular glutamatergic synapses, with the remaining synapses displaying reduced numbers of presynaptic vesicles. Chemo- and optogenetic studies in mice lacking GFRα1 revealed impaired circuit connectivity, reduced AMPA receptor postsynaptic currents, and abnormally low rectification index (R.I.) of AMPARs, suggesting reduced Ca2+ permeability. Further biochemical and proximity ligation assay (PLA) studies defined the presence of GluA1/GluA2 (Ca2+ impermeable) as well as GluA1/GluA4 (Ca2+ permeable) AMPAR complexes in mHb neurons, as well as clear differences in the levels and association of AMPAR subunits with mHb neurons lacking GFRα1. Finally, acute loss of GFRα1 in adult mHb neurons reduced anxiety-like behavior and potentiated context-based fear responses, phenocopying the effects of lesions to septal projections to the mHb. These results uncover an unexpected function for GFRα1 in the maintenance and function of adult glutamatergic synapses and reveal a potential new mechanism for regulating synaptic plasticity in the septohabenulointerpeduncular pathway and attuning of anxiety and fear behaviors.
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Affiliation(s)
- Diana Fernández-Suárez
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
- Department of Physiology and Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | | | - Katarzyna Pietrajtis
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine–Institut de Biologie Paris Seine (NPS-IBPS), Paris, France
| | - Annika Andersson
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Lilian Kisiswa
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | | | - Marco A. Diana
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine–Institut de Biologie Paris Seine (NPS-IBPS), Paris, France
| | - Carlos F. Ibáñez
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
- Department of Physiology and Life Sciences Institute, National University of Singapore, Singapore, Singapore
- Peking-Tsinghua Center for Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University School of Life Sciences and Chinese Institute for Brain Research, Beijing, China
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8
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Transcriptome programs involved in the development and structure of the cerebellum. Cell Mol Life Sci 2021; 78:6431-6451. [PMID: 34406416 PMCID: PMC8558292 DOI: 10.1007/s00018-021-03911-w] [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: 02/24/2021] [Accepted: 08/02/2021] [Indexed: 12/23/2022]
Abstract
In the past two decades, mounting evidence has modified the classical view of the cerebellum as a brain region specifically involved in the modulation of motor functions. Indeed, clinical studies and engineered mouse models have highlighted cerebellar circuits implicated in cognitive functions and behavior. Furthermore, it is now clear that insults occurring in specific time windows of cerebellar development can affect cognitive performance later in life and are associated with neurological syndromes, such as Autism Spectrum Disorder. Despite its almost homogenous cytoarchitecture, how cerebellar circuits form and function is not completely elucidated yet. Notably, the apparently simple neuronal organization of the cerebellum, in which Purkinje cells represent the only output, hides an elevated functional diversity even within the same neuronal population. Such complexity is the result of the integration of intrinsic morphogenetic programs and extracellular cues from the surrounding environment, which impact on the regulation of the transcriptome of cerebellar neurons. In this review, we briefly summarize key features of the development and structure of the cerebellum before focusing on the pathways involved in the acquisition of the cerebellar neuron identity. We focus on gene expression and mRNA processing programs, including mRNA methylation, trafficking and splicing, that are set in motion during cerebellar development and participate to its physiology. These programs are likely to add new layers of complexity and versatility that are fundamental for the adaptability of cerebellar neurons.
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De Vincenti AP, Alsina FC, Ferrero Restelli F, Hedman H, Ledda F, Paratcha G. Lrig1 and Lrig3 cooperate to control Ret receptor signaling, sensory axonal growth and epidermal innervation. Development 2021; 148:271159. [PMID: 34338291 DOI: 10.1242/dev.197020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 07/05/2021] [Indexed: 11/20/2022]
Abstract
Negative feedback loops represent a regulatory mechanism that guarantees that signaling thresholds are compatible with a physiological response. Previously, we established that Lrig1 acts through this mechanism to inhibit Ret activity. However, it is unclear whether other Lrig family members play similar roles. Here, we show that Lrig1 and Lrig3 are co-expressed in Ret-positive mouse dorsal root ganglion (DRG) neurons. Lrig3, like Lrig1, interacts with Ret and inhibits GDNF/Ret signaling. Treatment of DRG neurons with GDNF ligands induces a significant increase in the expression of Lrig1 and Lrig3. Our findings show that, whereas a single deletion of either Lrig1 or Lrig3 fails to promote Ret-mediated axonal growth, haploinsufficiency of Lrig1 in Lrig3 mutants significantly potentiates Ret signaling and axonal growth of DRG neurons in response to GDNF ligands. We observe that Lrig1 and Lrig3 act redundantly to ensure proper cutaneous innervation of nonpeptidergic axons and behavioral sensitivity to cold, which correlates with a significant increase in the expression of the cold-responsive channel TrpA1. Together, our findings provide insights into the in vivo functions through which Lrig genes control morphology, connectivity and function in sensory neurons.
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Affiliation(s)
- Ana Paula De Vincenti
- Laboratorio de Neurociencia Molecular y Celular, Instituto de Biología Celular y Neurociencias (IBCN)-CONICET-UBA, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, CP1121, Argentina
| | - Fernando C Alsina
- Laboratorio de Neurociencia Molecular y Celular, Instituto de Biología Celular y Neurociencias (IBCN)-CONICET-UBA, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, CP1121, Argentina
| | - Facundo Ferrero Restelli
- Laboratorio de Neurociencia Molecular y Celular, Instituto de Biología Celular y Neurociencias (IBCN)-CONICET-UBA, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, CP1121, Argentina
| | - Håkan Hedman
- Oncology Research Laboratory, Department of Radiation Sciences, Umeå University, Umeå, 901 87, Sweden
| | - Fernanda Ledda
- Laboratorio de Neurociencia Molecular y Celular, Instituto de Biología Celular y Neurociencias (IBCN)-CONICET-UBA, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, CP1121, Argentina.,Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires, Buenos Aires, C1405, Argentina
| | - Gustavo Paratcha
- Laboratorio de Neurociencia Molecular y Celular, Instituto de Biología Celular y Neurociencias (IBCN)-CONICET-UBA, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, CP1121, Argentina
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10
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Ohgami N, Iizuka A, Hirai H, Yajima I, Iida M, Shimada A, Tsuzuki T, Jijiwa M, Asai N, Takahashi M, Kato M. Loss-of-function mutation of c-Ret causes cerebellar hypoplasia in mice with Hirschsprung disease and Down's syndrome. J Biol Chem 2021; 296:100389. [PMID: 33561442 PMCID: PMC7950328 DOI: 10.1016/j.jbc.2021.100389] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 01/27/2021] [Accepted: 02/04/2021] [Indexed: 12/11/2022] Open
Abstract
The c-RET proto-oncogene encodes a receptor-tyrosine kinase. Loss-of-function mutations of RET have been shown to be associated with Hirschsprung disease and Down's syndrome (HSCR-DS) in humans. DS is known to involve cerebellar hypoplasia, which is characterized by reduced cerebellar size. Despite the fact that c-Ret has been shown to be associated with HSCR-DS in humans and to be expressed in Purkinje cells (PCs) in experimental animals, there is limited information about the role of activity of c-Ret/c-RET kinase in cerebellar hypoplasia. We found that a loss-of-function mutation of c-Ret Y1062 in PCs causes cerebellar hypoplasia in c-Ret mutant mice. Wild-type mice had increased phosphorylation of c-Ret in PCs during postnatal development, while c-Ret mutant mice had postnatal hypoplasia of the cerebellum with immature neurite outgrowth in PCs and granule cells (GCs). c-Ret mutant mice also showed decreased numbers of glial fibers and mitogenic sonic hedgehog (Shh)-positive vesicles in the external germinal layer of PCs. c-Ret-mediated cerebellar hypoplasia was rescued by subcutaneous injection of a smoothened agonist (SAG) as well as by reduced expression of Patched1, a negative regulator for Shh. Our results suggest that the loss-of-function mutation of c-Ret Y1062 results in the development of cerebellar hypoplasia via impairment of the Shh-mediated development of GCs and glial fibers in mice with HSCR-DS.
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Affiliation(s)
- Nobutaka Ohgami
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan; Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi, Japan
| | - Akira Iizuka
- Department of Neurophysiology and Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Hirokazu Hirai
- Department of Neurophysiology and Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Ichiro Yajima
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Machiko Iida
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Atsuyoshi Shimada
- Pathology Research Team, Faculty of Health Sciences, Kyorin University, Mitaka, Tokyo, Japan
| | - Toyonori Tsuzuki
- Department of Surgical Pathology, Aichi Medical University Hospital, Nagakute, Aichi, Japan
| | - Mayumi Jijiwa
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Naoya Asai
- Department of Pathology, Fujita Health University, Toyoake, Aichi, Japan
| | - Masahide Takahashi
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan; International Center for Cell and Gene Therapy, Fujita Health University, Toyoake, Aichi, Japan
| | - Masashi Kato
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan; Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi, Japan.
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11
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Kim J, Augustine GJ. Molecular Layer Interneurons: Key Elements of Cerebellar Network Computation and Behavior. Neuroscience 2020; 462:22-35. [PMID: 33075461 DOI: 10.1016/j.neuroscience.2020.10.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/02/2020] [Accepted: 10/05/2020] [Indexed: 02/05/2023]
Abstract
Molecular layer interneurons (MLIs) play an important role in cerebellar information processing by controlling Purkinje cell (PC) activity via inhibitory synaptic transmission. A local MLI network, constructed from both chemical and electrical synapses, is organized into spatially structured clusters that amplify feedforward and lateral inhibition to shape the temporal and spatial patterns of PC activity. Several recent in vivo studies indicate that such MLI circuits contribute not only to sensorimotor information processing, but also to precise motor coordination and cognitive processes. Here, we review current understanding of the organization of MLI circuits and their roles in the function of the mammalian cerebellum.
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Affiliation(s)
- Jinsook Kim
- Lee Kong Chian School of Medicine Nanyang Technological University Singapore 308238, Singapore
| | - George J Augustine
- Lee Kong Chian School of Medicine Nanyang Technological University Singapore 308238, Singapore.
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12
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The γ-Protocadherins Regulate the Survival of GABAergic Interneurons during Developmental Cell Death. J Neurosci 2020; 40:8652-8668. [PMID: 33060174 DOI: 10.1523/jneurosci.1636-20.2020] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 09/23/2020] [Accepted: 09/29/2020] [Indexed: 12/15/2022] Open
Abstract
Inhibitory interneurons integrate into developing circuits in specific ratios and distributions. In the neocortex, inhibitory network formation occurs concurrently with the apoptotic elimination of a third of GABAergic interneurons. The cell surface molecules that select interneurons to survive or die are unknown. Here, we report that members of the clustered Protocadherins (cPCDHs) control GABAergic interneuron survival during developmentally-regulated cell death. Conditional deletion of the gene cluster encoding the γ-Protocadherins (Pcdhgs) from developing GABAergic neurons in mice of either sex causes a severe loss of inhibitory populations in multiple brain regions and results in neurologic deficits such as seizures. By focusing on the neocortex and the cerebellar cortex, we demonstrate that reductions of inhibitory interneurons result from elevated apoptosis during the critical postnatal period of programmed cell death (PCD). By contrast, cortical interneuron (cIN) populations are not affected by removal of Pcdhgs from pyramidal neurons or glial cells. Interneuron loss correlates with reduced AKT signaling in Pcdhg mutant interneurons, and is rescued by genetic blockade of the pro-apoptotic factor BAX. Together, these findings identify the PCDHGs as pro-survival transmembrane proteins that select inhibitory interneurons for survival and modulate the extent of PCD. We propose that the PCDHGs contribute to the formation of balanced inhibitory networks by controlling the size of GABAergic interneuron populations in the developing brain.SIGNIFICANCE STATEMENT A pivotal step for establishing appropriate excitatory-inhibitory ratios is adjustment of neuronal populations by cell death. In the mouse neocortex, a third of GABAergic interneurons are eliminated by BAX-dependent apoptosis during the first postnatal week. Interneuron cell death is modulated by neural activity and pro-survival pathways but the cell-surface molecules that select interneurons for survival or death are unknown. We demonstrate that members of the cadherin superfamily, the clustered γ-Protocadherins (PCDHGs), regulate the survival of inhibitory interneurons and the balance of cell death. Deletion of the Pcdhgs in mice causes inhibitory interneuron loss in the cortex and cerebellum, and leads to motor deficits and seizures. Our findings provide a molecular basis for controlling inhibitory interneuron population size during circuit formation.
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Zhou J, Brown AM, Lackey EP, Arancillo M, Lin T, Sillitoe RV. Purkinje cell neurotransmission patterns cerebellar basket cells into zonal modules defined by distinct pinceau sizes. eLife 2020; 9:55569. [PMID: 32990595 PMCID: PMC7561353 DOI: 10.7554/elife.55569] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 09/29/2020] [Indexed: 01/05/2023] Open
Abstract
Ramón y Cajal proclaimed the neuron doctrine based on circuit features he exemplified using cerebellar basket cell projections. Basket cells form dense inhibitory plexuses that wrap Purkinje cell somata and terminate as pinceaux at the initial segment of axons. Here, we demonstrate that HCN1, Kv1.1, PSD95 and GAD67 unexpectedly mark patterns of basket cell pinceaux that map onto Purkinje cell functional zones. Using cell-specific genetic tracing with an Ascl1CreERT2 mouse conditional allele, we reveal that basket cell zones comprise different sizes of pinceaux. We tested whether Purkinje cells instruct the assembly of inhibitory projections into zones, as they do for excitatory afferents. Genetically silencing Purkinje cell neurotransmission blocks the formation of sharp Purkinje cell zones and disrupts excitatory axon patterning. The distribution of pinceaux into size-specific zones is eliminated without Purkinje cell GABAergic output. Our data uncover the cellular and molecular diversity of a foundational synapse that revolutionized neuroscience.
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Affiliation(s)
- Joy Zhou
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, United States.,Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, United States
| | - Amanda M Brown
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, United States.,Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, United States
| | - Elizabeth P Lackey
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, United States.,Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, United States
| | - Marife Arancillo
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, United States.,Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, United States
| | - Tao Lin
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, United States.,Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, United States
| | - Roy V Sillitoe
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, United States.,Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, United States.,Program in Developmental Biology, Baylor College of Medicine, Houston, United States
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14
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Refinement of Cerebellar Network Organization by Extracellular Signaling During Development. Neuroscience 2020; 462:44-55. [PMID: 32502568 DOI: 10.1016/j.neuroscience.2020.05.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 12/21/2022]
Abstract
The cerebellum forms regular neural network structures consisting of a few major types of neurons, such as Purkinje cells, granule cells, and molecular layer interneurons, and receives two major inputs from climbing fibers and mossy fibers. Its regular structures consist of three well-defined layers, with each type of neuron designated to a specific location and forming specific synaptic connections. During the first few weeks of postnatal development in rodents, the cerebellum goes through dynamic changes via proliferation, migration, differentiation, synaptogenesis, and maturation, to create such a network structure. The development of this organized network structure presumably relies on the communication between developing elements in the network, including not only individual neurons, but also their dendrites, axons, and synapses. Therefore, it is reasonable that extracellular signaling via synaptic transmission, secreted molecules, and cell adhesion molecules, plays important roles in cerebellar network development. Although it is not yet clear as to how overall cerebellar development is orchestrated, there is indeed accumulating lines of evidence that extracellular signaling acts toward the development of individual elements in the cerebellar networks. In this article, we introduce what we have learned from many studies regarding the extracellular signaling required for cerebellar network development, including our recent study suggesting the importance of unbiased synaptic inputs from parallel fibers.
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15
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Wu GY, Liu SL, Yao J, Li X, Wu B, Ye JN, Sui JF. Optogenetic Inhibition of Medial Prefrontal Cortex-Pontine Nuclei Projections During the Stimulus-free Trace Interval Impairs Temporal Associative Motor Learning. Cereb Cortex 2019; 28:3753-3763. [PMID: 28968654 DOI: 10.1093/cercor/bhx238] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Indexed: 11/13/2022] Open
Abstract
The medial prefrontal cortex (mPFC) is closely involved in many higher-order cognitive functions, including learning to associate temporally discontiguous events (called temporal associative learning). However, direct evidence for the role of mPFC and the neural pathway underlying modulation of temporal associative motor learning is sparse. Here, we show that optogenetic inhibition of the mPFC or its axon terminals at the pontine nuclei (PN) during trace intervals or whole trial period significantly impaired the trace eyeblink conditioning (TEC), but had no significant effects on TEC during the conditioned stimulus or intertrial interval period. Our results suggest that activities associated with the mPFC-PN projection during trace intervals is crucial for trace associative motor learning. This finding is of great importance in understanding the mechanisms and the relevant neural pathways underlying mPFC modulation of temporal associative motor learning.
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Affiliation(s)
- Guang-Yan Wu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Shu-Lei Liu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Juan Yao
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Xuan Li
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Bing Wu
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Jian-Ning Ye
- Department of Neurology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Jian-Feng Sui
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
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16
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Park H, Kim T, Kim J, Yamamoto Y, Tanaka-Yamamoto K. Inputs from Sequentially Developed Parallel Fibers Are Required for Cerebellar Organization. Cell Rep 2019; 28:2939-2954.e5. [DOI: 10.1016/j.celrep.2019.08.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 06/10/2019] [Accepted: 07/30/2019] [Indexed: 11/15/2022] Open
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17
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Maurin T, Lebrigand K, Castagnola S, Paquet A, Jarjat M, Popa A, Grossi M, Rage F, Bardoni B. HITS-CLIP in various brain areas reveals new targets and new modalities of RNA binding by fragile X mental retardation protein. Nucleic Acids Res 2019; 46:6344-6355. [PMID: 29668986 PMCID: PMC6158598 DOI: 10.1093/nar/gky267] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 03/29/2018] [Indexed: 01/19/2023] Open
Abstract
Fragile X syndrome (FXS), the most common form of inherited intellectual disability, is due to the functional deficiency of the fragile X mental retardation protein (FMRP), an RNA-binding protein involved in translational regulation of many messenger RNAs, playing key roles in synaptic morphology and plasticity. To date, no effective treatment for FXS is available. We searched for FMRP targets by HITS-CLIP during early development of multiple mouse brain regions (hippocampus, cortex and cerebellum) at a time of brain development when FMRP is most highly expressed and synaptogenesis reaches a peak. We identified the largest dataset of mRNA targets of FMRP available in brain and we defined their cellular origin. We confirmed the G-quadruplex containing structure as an enriched motif in FMRP RNA targets. In addition to four less represented motifs, our study points out that, in the brain, CTGKA is the prominent motif bound by FMRP, which recognizes it when not engaged in Watson–Crick pairing. All of these motifs negatively modulated the expression level of a reporter protein. While the repertoire of FMRP RNA targets in cerebellum is quite divergent, the ones of cortex and hippocampus are vastly overlapping. In these two brain regions, the Phosphodiesterase 2a (Pde2a) mRNA is a prominent target of FMRP, which modulates its translation and intracellular transport. This enzyme regulates the homeostasis of cAMP and cGMP and represents a novel and attractive therapeutic target to treat FXS.
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Affiliation(s)
- Thomas Maurin
- Université Côte d'Azur, CNRS, IPMC, 06560 Valbonne, France.,CNRS LIA « Neogenex », 06560 Valbonne, France
| | | | - Sara Castagnola
- Université Côte d'Azur, CNRS, IPMC, 06560 Valbonne, France.,CNRS LIA « Neogenex », 06560 Valbonne, France
| | - Agnès Paquet
- Université Côte d'Azur, CNRS, IPMC, 06560 Valbonne, France
| | - Marielle Jarjat
- Université Côte d'Azur, CNRS, IPMC, 06560 Valbonne, France.,CNRS LIA « Neogenex », 06560 Valbonne, France
| | - Alexandra Popa
- Research Center for Molecular Medicine of the Austrian Academy of Sciences, A-1090 Vienna, Austria
| | - Mauro Grossi
- Université Côte d'Azur, CNRS, IPMC, 06560 Valbonne, France.,CNRS LIA « Neogenex », 06560 Valbonne, France
| | - Florence Rage
- CNRS, Institut de Génétique Moléculaire, 34293 Montpellier, France
| | - Barbara Bardoni
- CNRS LIA « Neogenex », 06560 Valbonne, France.,Université Côte d'Azur, INSERM, CNRS, IPMC, 06560 Valbonne, France
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18
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Brown AM, Arancillo M, Lin T, Catt DR, Zhou J, Lackey EP, Stay TL, Zuo Z, White JJ, Sillitoe RV. Molecular layer interneurons shape the spike activity of cerebellar Purkinje cells. Sci Rep 2019; 9:1742. [PMID: 30742002 PMCID: PMC6370775 DOI: 10.1038/s41598-018-38264-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 12/14/2018] [Indexed: 12/03/2022] Open
Abstract
Purkinje cells receive synaptic input from several classes of interneurons. Here, we address the roles of inhibitory molecular layer interneurons in establishing Purkinje cell function in vivo. Using conditional genetics approaches in mice, we compare how the lack of stellate cell versus basket cell GABAergic neurotransmission sculpts the firing properties of Purkinje cells. We take advantage of an inducible Ascl1CreER allele to spatially and temporally target the deletion of the vesicular GABA transporter, Vgat, in developing neurons. Selective depletion of basket cell GABAergic neurotransmission increases the frequency of Purkinje cell simple spike firing and decreases the frequency of complex spike firing in adult behaving mice. In contrast, lack of stellate cell communication increases the regularity of Purkinje cell simple spike firing while increasing the frequency of complex spike firing. Our data uncover complementary roles for molecular layer interneurons in shaping the rate and pattern of Purkinje cell activity in vivo.
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Affiliation(s)
- Amanda M Brown
- Department of Pathology and Immunology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, Texas, 77030, USA
| | - Marife Arancillo
- Department of Pathology and Immunology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, Texas, 77030, USA
| | - Tao Lin
- Department of Pathology and Immunology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, Texas, 77030, USA
| | - Daniel R Catt
- Department of Pathology and Immunology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, Texas, 77030, USA
| | - Joy Zhou
- Department of Pathology and Immunology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, Texas, 77030, USA
| | - Elizabeth P Lackey
- Department of Pathology and Immunology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, Texas, 77030, USA
| | - Trace L Stay
- Department of Pathology and Immunology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, Texas, 77030, USA
| | - Zhongyuan Zuo
- Department of Pathology and Immunology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, Texas, 77030, USA
| | - Joshua J White
- Department of Pathology and Immunology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, Texas, 77030, USA
| | - Roy V Sillitoe
- Department of Pathology and Immunology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA.
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA.
- Program in Developmental Biology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA.
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, Texas, 77030, USA.
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19
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Neonatal brain injury causes cerebellar learning deficits and Purkinje cell dysfunction. Nat Commun 2018; 9:3235. [PMID: 30104642 PMCID: PMC6089917 DOI: 10.1038/s41467-018-05656-w] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 07/16/2018] [Indexed: 11/08/2022] Open
Abstract
Premature infants are more likely to develop locomotor disorders than term infants. In a chronic sub-lethal hypoxia (Hx) mouse model of neonatal brain injury, we recently demonstrated the presence of cellular and physiological changes in the cerebellar white matter. We also observed Hx-induced delay in Purkinje cell (PC) arborization. However, the behavioral consequences of these cellular alterations remain unexplored. Using the Erasmus Ladder to study cerebellar behavior, we report the presence of locomotor malperformance and long-term cerebellar learning deficits in Hx mice. Optogenetics experiments in Hx mice reveal a profound reduction in spontaneous and photoevoked PC firing frequency. Finally, treatment with a gamma-aminobutyric acid (GABA) reuptake inhibitor partially rescues locomotor performance and improves PC firing. Our results demonstrate a long-term miscoordination phenotype characterized by locomotor malperformance and cerebellar learning deficits in a mouse model of neonatal brain injury. Our findings also implicate the developing GABA network as a potential therapeutic target for prematurity-related locomotor deficits.
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20
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Kisiswa L, Fernández-Suárez D, Sergaki MC, Ibáñez CF. RIP2 Gates TRAF6 Interaction with Death Receptor p75 NTR to Regulate Cerebellar Granule Neuron Survival. Cell Rep 2018; 24:1013-1024. [PMID: 30044969 DOI: 10.1016/j.celrep.2018.06.098] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 06/01/2018] [Accepted: 06/22/2018] [Indexed: 02/07/2023] Open
Abstract
Cerebellar granule neurons (CGNs) undergo programmed cell death during the first postnatal week of mouse development, coincident with sustained expression of the death receptor p75NTR. Although ablation of p75NTR does not affect CGN cell death, deletion of the downstream effector RIP2 significantly increases CGN apoptosis, resulting in reduced adult CGN number and impaired behaviors associated with cerebellar function. Remarkably, CGN death is restored to basal levels when p75NTR is deleted in RIP2-deficient mice. We find that RIP2 gates the signaling output of p75NTR by competing with TRAF6 for binding to the receptor intracellular domain. In CGNs lacking RIP2, more TRAF6 is associated with p75NTR, leading to increased JNK-dependent apoptosis. In agreement with this, pharmacological inhibition or genetic ablation of TRAF6 restores cell death levels in CGNs lacking RIP2. These results reveal an unexpected mechanism controlling CGN number and highlight how competitive interactions govern the logic of death receptor function.
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Affiliation(s)
- Lilian Kisiswa
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm 17177, Sweden
| | | | | | - Carlos F Ibáñez
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm 17177, Sweden; Department of Physiology, National University of Singapore, Singapore 117597, Singapore; Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore.
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21
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Zechel S, Fernandez-Suarez D, Ibáñez CF. Cell-autonomous role of GFRα1 in the development of olfactory bulb GABAergic interneurons. Biol Open 2018; 7:bio.033753. [PMID: 29716946 PMCID: PMC5992528 DOI: 10.1242/bio.033753] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
GFRα1, a receptor for glial cell line-derived neurotrophic factor (GDNF), is critical for the development of the main olfactory system. The olfactory bulb (OB) of Gfra1 knockout mice shows significant reductions in the number of olfactory sensory neurons, mitral and tufted cells, as well as all major classes of OB GABAergic interneurons. However, the latter do not express significant levels of GFRα1, leaving the mechanism of action of GFRα1 in OB interneuron development unexplained. Here we report that GFRα1 is highly expressed in the precursor cells that give rise to all major classes of OB interneurons, but is downregulated as these neurons mature. Conditional ablation of GFRα1 in embryonic GABAergic cells recapitulated the cell losses observed in global Gfra1 knockouts at birth. GFRα1 was also required for the sustained generation and allocation of OB interneurons in adulthood. Conditional loss of GFRα1 altered the migratory behaviour of neuroblasts along the rostral migratory stream (RMS) as well as RMS glial tunnel formation. Together, these data indicate that GFRα1 functions cell-autonomously in subpopulations of OB interneuron precursors to regulate their generation and allocation in the mammalian OB. Summary: Our data indicate that GFRα1 functions cell-autonomously in subpopulations of OB interneuron precursors to regulate their generation and allocation in the mammalian OB.
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Affiliation(s)
- Sabrina Zechel
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm 17177, Sweden
| | | | - Carlos F Ibáñez
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm 17177, Sweden .,Department of Physiology, National University of Singapore, Singapore 117597, Singapore.,Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore.,Stellenbosch Institute for Advanced Study, Wallenberg Research Centre at Stellenbosch University, Stellenbosch 7600, South Africa
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