201
|
Origin of a Non-Clarke's Column Division of the Dorsal Spinocerebellar Tract and the Role of Caudal Proprioceptive Neurons in Motor Function. Cell Rep 2015; 13:1258-1271. [PMID: 26527010 DOI: 10.1016/j.celrep.2015.09.064] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 08/24/2015] [Accepted: 09/22/2015] [Indexed: 01/09/2023] Open
Abstract
Proprioception, the sense of limb and body position, is essential for generating proper movement. Unconscious proprioceptive information travels through cerebellar-projecting neurons in the spinal cord and medulla. The progenitor domain defined by the basic-helix-loop-helix (bHLH) transcription factor, ATOH1, has been implicated in forming these cerebellar-projecting neurons; however, their precise contribution to proprioceptive tracts and motor behavior is unknown. Significantly, we demonstrate that Atoh1-lineage neurons in the spinal cord reside outside Clarke's column (CC), a main contributor of neurons relaying hindlimb proprioception, despite giving rise to the anatomical and functional correlate of CC in the medulla, the external cuneate nucleus (ECu), which mediates forelimb proprioception. Elimination of caudal Atoh1-lineages results in mice with relatively normal locomotion but unable to perform coordinated motor tasks. Altogether, we reveal that proprioceptive nuclei in the spinal cord and medulla develop from more than one progenitor source, suggesting an avenue to uncover distinct proprioceptive functions.
Collapse
|
202
|
Yang R, Wang M, Wang J, Huang X, Yang R, Gao WQ. Cell Division Mode Change Mediates the Regulation of Cerebellar Granule Neurogenesis Controlled by the Sonic Hedgehog Signaling. Stem Cell Reports 2015; 5:816-828. [PMID: 26527387 PMCID: PMC4649382 DOI: 10.1016/j.stemcr.2015.09.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 09/25/2015] [Accepted: 09/25/2015] [Indexed: 01/11/2023] Open
Abstract
Symmetric and asymmetric divisions are important for self-renewal and differentiation of stem cells during neurogenesis. Although cerebellar granule neurogenesis is controlled by sonic hedgehog (SHH) signaling, whether and how this process is mediated by regulation of cell division modes have not been determined. Here, using time-lapse imaging and cell culture from neuronal progenitor-specific and differentiated neuron-specific reporter mouse lines (Math1-GFP and Dcx-DsRed) and Patched ± mice in which SHH signaling is activated, we find evidence for the existence of symmetric and asymmetric divisions that are closely associated with progenitor proliferation and differentiation. While activation of the SHH pathway enhances symmetric progenitor cell divisions, blockade of the SHH pathway reverses the cell division mode change in Math1-GFP; Dcx-DsRed; Patched ± mice by promoting asymmetric divisions or terminal neuronal symmetric divisions. Thus, cell division mode change mediates the regulation of cerebellar granule neurogenesis controlled by SHH signaling.
Collapse
Affiliation(s)
- Rong Yang
- State Key Laboratory of Oncogenes and Related Genes, Renji-MedX Stem Cell Research Center, Ren Ji Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Minglei Wang
- State Key Laboratory of Oncogenes and Related Genes, Renji-MedX Stem Cell Research Center, Ren Ji Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Jia Wang
- State Key Laboratory of Oncogenes and Related Genes, Renji-MedX Stem Cell Research Center, Ren Ji Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Xingxu Huang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Ru Yang
- State Key Laboratory of Oncogenes and Related Genes, Renji-MedX Stem Cell Research Center, Ren Ji Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China.
| | - Wei-Qiang Gao
- State Key Laboratory of Oncogenes and Related Genes, Renji-MedX Stem Cell Research Center, Ren Ji Hospital, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China; Collaborative Innovation Center of Systems Biomedicine, Shanghai 200240, China.
| |
Collapse
|
203
|
Hayashi Y, Kashiwagi M, Yasuda K, Ando R, Kanuka M, Sakai K, Itohara S. Cells of a common developmental origin regulate REM/non-REM sleep and wakefulness in mice. Science 2015; 350:957-61. [PMID: 26494173 DOI: 10.1126/science.aad1023] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 10/07/2015] [Indexed: 12/17/2022]
Abstract
Mammalian sleep comprises rapid eye movement (REM) sleep and non-REM (NREM) sleep. To functionally isolate from the complex mixture of neurons populating the brainstem pons those involved in switching between REM and NREM sleep, we chemogenetically manipulated neurons of a specific embryonic cell lineage in mice. We identified excitatory glutamatergic neurons that inhibit REM sleep and promote NREM sleep. These neurons shared a common developmental origin with neurons promoting wakefulness; both derived from a pool of proneural hindbrain cells expressing Atoh1 at embryonic day 10.5. We also identified inhibitory γ-aminobutyric acid-releasing neurons that act downstream to inhibit REM sleep. Artificial reduction or prolongation of REM sleep in turn affected slow-wave activity during subsequent NREM sleep, implicating REM sleep in the regulation of NREM sleep.
Collapse
Affiliation(s)
- Yu Hayashi
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai Tsukuba, Ibaraki 305-8575, Japan. Japan Science and Technology Agency (JST), PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan.
| | - Mitsuaki Kashiwagi
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai Tsukuba, Ibaraki 305-8575, Japan
| | - Kosuke Yasuda
- Laboratory for Behavioral Genetics, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako-city, Saitama 351-0198, Japan
| | - Reiko Ando
- Laboratory for Behavioral Genetics, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako-city, Saitama 351-0198, Japan
| | - Mika Kanuka
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai Tsukuba, Ibaraki 305-8575, Japan
| | - Kazuya Sakai
- Integrative Physiology of the Brain Arousal System, Lyon Neuroscience Research Center, INSERM U1028-CNRS UMR5292, School of Medicine, Claude Bernard University Lyon 1, F-69373 Lyon, France
| | - Shigeyoshi Itohara
- Laboratory for Behavioral Genetics, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako-city, Saitama 351-0198, Japan.
| |
Collapse
|
204
|
Morello F, Partanen J. Diversity and development of local inhibitory and excitatory neurons associated with dopaminergic nuclei. FEBS Lett 2015; 589:3693-701. [PMID: 26453835 DOI: 10.1016/j.febslet.2015.10.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 09/28/2015] [Accepted: 10/01/2015] [Indexed: 12/18/2022]
Abstract
For regulation of voluntary movement and motivation the midbrain dopaminergic system receives input from a variety of brain regions. Often this input is mediated by local non-dopaminergic neurons within or closely associated with the dopaminergic nuclei. In addition to the dopaminergic neurons, some of these non-dopaminergic neurons also send functionally important output from the ventral midbrain to forebrain targets. The aim of this review is to introduce subtypes of GABAergic and glutamatergic neurons, which are located in the dopaminergic nuclei or the adjacent brainstem and are important for the regulation of the dopaminergic pathways. In addition, we discuss recent studies beginning to reveal mechanisms for their development, which may hold the key to understanding the diversity of these neurons.
Collapse
Affiliation(s)
- Francesca Morello
- Department of Biosciences, Division of Genetics, P.O. Box 56, Viikinkaari 9, 00014 University of Helsinki, Helsinki, Finland
| | - Juha Partanen
- Department of Biosciences, Division of Genetics, P.O. Box 56, Viikinkaari 9, 00014 University of Helsinki, Helsinki, Finland.
| |
Collapse
|
205
|
Vriend J, Ghavami S, Marzban H. The role of the ubiquitin proteasome system in cerebellar development and medulloblastoma. Mol Brain 2015; 8:64. [PMID: 26475605 PMCID: PMC4609148 DOI: 10.1186/s13041-015-0155-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 10/08/2015] [Indexed: 01/12/2023] Open
Abstract
Cerebellar granule cells precursors are derived from the upper rhombic lip and migrate tangentially independent of glia along the subpial stream pathway to form the external germinal zone. Postnatally, granule cells migrate from the external germinal zone radially through the Purkinje cell layer, guided by Bergmann glia fibers, to the internal granular cell layer. Medulloblastomas (MBs) are the most common malignant childhood brain tumor. Many of these tumors develop from precursor cells of the embryonic rhombic lips. Four main groups of MB are recognized. The WNT group of MBs arise primarily from the lower rhombic lip and embryonic brainstem. The SHH group of MBs originate from cerebellar granule cell precursors in the external germinal zone of the embryonic cerebellum. The cellular origins of type 3 and type 4 MBs are not clear. Several ubiquitin ligases are revealed to be significant factors in development of the cerebellum as well as in the initiation and maintenance of MBs. Proteasome dysfunction at a critical stage of development may be a major factor in determining whether progenitor cells which are destined to become granule cells differentiate normally or become MB cells. We propose the hypothesis that proteasomal activity is essential to regulate the critical transition between proliferating granule cells and differentiated granule cells and that proteasome dysfunction may lead to MB. Proteasome dysfunction could also account for various mutations in MBs resulting from deficiencies in DNA checkpoint and repair mechanisms prior to development of MBs. Data showing a role for the ubiquitin ligases β-TrCP, FBW7, Huwe1, and SKP2 in MBs suggest the possibility of a classification of MBs based on the expression (over expression or under expression) of specific ubiquitin ligases which function as oncogenes, tumor suppressors or cell cycle regulators.
Collapse
Affiliation(s)
- Jerry Vriend
- Department of Human Anatomy and Cell Science, Rm129, BMSB, 745 Bannatyne Avenue, Winnipeg, MB, Canada
| | - Saeid Ghavami
- Department of Human Anatomy and Cell Science, Rm129, BMSB, 745 Bannatyne Avenue, Winnipeg, MB, Canada.,Children's Hospital Research Institute of Manitoba (CHRIM), College of Medicine, Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada
| | - Hassan Marzban
- Department of Human Anatomy and Cell Science, Rm129, BMSB, 745 Bannatyne Avenue, Winnipeg, MB, Canada. .,Children's Hospital Research Institute of Manitoba (CHRIM), College of Medicine, Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada.
| |
Collapse
|
206
|
Williams SE, Garcia I, Crowther AJ, Li S, Stewart A, Liu H, Lough KJ, O'Neill S, Veleta K, Oyarzabal EA, Merrill JR, Shih YYI, Gershon TR. Aspm sustains postnatal cerebellar neurogenesis and medulloblastoma growth in mice. Development 2015; 142:3921-32. [PMID: 26450969 DOI: 10.1242/dev.124271] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 09/28/2015] [Indexed: 01/06/2023]
Abstract
Alterations in genes that regulate brain size may contribute to both microcephaly and brain tumor formation. Here, we report that Aspm, a gene that is mutated in familial microcephaly, regulates postnatal neurogenesis in the cerebellum and supports the growth of medulloblastoma, the most common malignant pediatric brain tumor. Cerebellar granule neuron progenitors (CGNPs) express Aspm when maintained in a proliferative state by sonic hedgehog (Shh) signaling, and Aspm is expressed in Shh-driven medulloblastoma in mice. Genetic deletion of Aspm reduces cerebellar growth, while paradoxically increasing the mitotic rate of CGNPs. Aspm-deficient CGNPs show impaired mitotic progression, altered patterns of division orientation and differentiation, and increased DNA damage, which causes progenitor attrition through apoptosis. Deletion of Aspm in mice with Smo-induced medulloblastoma reduces tumor growth and increases DNA damage. Co-deletion of Aspm and either of the apoptosis regulators Bax or Trp53 (also known as p53) rescues the survival of neural progenitors and reduces the growth restriction imposed by Aspm deletion. Our data show that Aspm functions to regulate mitosis and to mitigate DNA damage during CGNP cell division, causes microcephaly through progenitor apoptosis when mutated, and sustains tumor growth in medulloblastoma.
Collapse
Affiliation(s)
- Scott E Williams
- Department of Pathology & Laboratory Medicine, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Idoia Garcia
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Andrew J Crowther
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Shiyi Li
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Alyssa Stewart
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Hedi Liu
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Kendall J Lough
- Department of Pathology & Laboratory Medicine, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Sean O'Neill
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Katherine Veleta
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Esteban A Oyarzabal
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Joseph R Merrill
- Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Yen-Yu Ian Shih
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, NC 27599, USA Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Timothy R Gershon
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| |
Collapse
|
207
|
Sotelo C. Molecular layer interneurons of the cerebellum: developmental and morphological aspects. CEREBELLUM (LONDON, ENGLAND) 2015; 14:534-56. [PMID: 25599913 DOI: 10.1007/s12311-015-0648-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
During the past 25 years, our knowledge on the development of basket and stellate cells (molecular layer interneurons [MLIs]) has completely changed, not only regarding their origin from the ventricular zone, corresponding to the primitive cerebellar neuroepithelium, instead of the external granular layer, but above all by providing an almost complete account of the genetic regulations (transcription factors and other genes) involved in their differentiation and synaptogenesis. Moreover, it has been shown that MLIs' precursors (dividing neuroblasts) and not young postmitotic neurons, as in other germinal neuroepithelia, leave the germinative zone and migrate all along a complex and lengthy path throughout the presumptive cerebellar white matter, which provides suitable niches exerting epigenetic influences on their ultimate neuronal identities. Recent studies carried out on the anatomical-functional properties of adult MLIs emphasize the importance of these interneurons in regulating PC inhibition, and point out the crucial role played by electrical synaptic transmission between MLIs as well as ephaptic interactions between them and Purkinje cells at the pinceaux level, in the regulation of this inhibition.
Collapse
Affiliation(s)
- Constantino Sotelo
- INSERM, UMRS_U968, Institut de la Vision, 17 Rue Moreau, Paris, 75012, France.
- Institut de la Vision, Sorbonne Université, UPMC Univ Paris 06, Paris, 75012, France.
- CNRS, UMR_7210, Paris, 75012, France.
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Miguel Hernández (UMH), Avenida Ramón y Cajal s/n, 03550, San Juan de Alicante, Spain.
| |
Collapse
|
208
|
Hara S, Kaneyama T, Inamata Y, Onodera R, Shirasaki R. Interstitial branch formation within the red nucleus by deep cerebellar nuclei-derived commissural axons during target recognition. J Comp Neurol 2015; 524:999-1014. [DOI: 10.1002/cne.23888] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 07/29/2015] [Accepted: 08/21/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Satoshi Hara
- Cellular and Molecular Neurobiology Laboratory, Graduate School of Frontier Biosciences; Osaka University; Suita Osaka 565-0871 Japan
| | - Takeshi Kaneyama
- Cellular and Molecular Neurobiology Laboratory, Graduate School of Frontier Biosciences; Osaka University; Suita Osaka 565-0871 Japan
| | - Yasuyuki Inamata
- Cellular and Molecular Neurobiology Laboratory, Graduate School of Frontier Biosciences; Osaka University; Suita Osaka 565-0871 Japan
| | - Ryota Onodera
- Cellular and Molecular Neurobiology Laboratory, Graduate School of Frontier Biosciences; Osaka University; Suita Osaka 565-0871 Japan
| | - Ryuichi Shirasaki
- Cellular and Molecular Neurobiology Laboratory, Graduate School of Frontier Biosciences; Osaka University; Suita Osaka 565-0871 Japan
| |
Collapse
|
209
|
Dever DP, Adham ZO, Thompson B, Genestine M, Cherry J, Olschowka JA, DiCicco-Bloom E, Opanashuk LA. Aryl hydrocarbon receptor deletion in cerebellar granule neuron precursors impairs neurogenesis. Dev Neurobiol 2015; 76:533-50. [PMID: 26243376 DOI: 10.1002/dneu.22330] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 07/28/2015] [Indexed: 11/12/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated member of the basic-helix-loop-helix/PER-ARNT-SIM(PAS) transcription factor superfamily that also mediates the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Increasing evidence suggests that AhR influences the development of many tissues, including the central nervous system. Our previous studies suggest that sustained AhR activation by TCDD and/or AhR deletion disrupts cerebellar granule neuron precursor (GNP) development. In the current study, to determine whether endogenous AhR controls GNP development in a cell-autonomous manner, we created a GNP-specific AhR deletion mouse, AhR(fx/fx) /Math1(CRE/+) (AhR CKO). Selective AhR deletion in GNPs produced abnormalities in proliferation and differentiation. Specifically, fewer GNPs were engaged in S-phase, as demonstrated by ∼25% reductions in thymidine (in vitro) and Bromodeoxyuridine (in vivo) incorporation. Furthermore, total granule neuron numbers in the internal granule layer at PND21 and PND60 were diminished in AhR conditional knockout (CKO) mice compared with controls. Conversely, differentiation was enhanced, including ∼40% increase in neurite outgrowth and 50% increase in GABARα6 receptor expression in deletion mutants. Our results suggest that AhR activity plays a role in regulating granule neuron number and differentiation, possibly by coordinating this GNP developmental transition. These studies provide novel insights for understanding the normal roles of AhR signaling during cerebellar granule cell neurogenesis and may have important implications for the effects of environmental factors in cerebellar dysgenesis.
Collapse
Affiliation(s)
- Daniel P Dever
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642
| | - Zachariah O Adham
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642
| | - Bryan Thompson
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642
| | - Matthieu Genestine
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854
| | - Jonathan Cherry
- Department of Pathology and Laboratory Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642
| | - John A Olschowka
- Department of Neurobiology and Anatomy, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642
| | - Emanuel DiCicco-Bloom
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854
| | - Lisa A Opanashuk
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642
| |
Collapse
|
210
|
Bergeron SA, Carrier N, Li GH, Ahn S, Burgess HA. Gsx1 expression defines neurons required for prepulse inhibition. Mol Psychiatry 2015; 20:974-85. [PMID: 25224259 PMCID: PMC4362800 DOI: 10.1038/mp.2014.106] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 07/09/2014] [Accepted: 08/04/2014] [Indexed: 02/07/2023]
Abstract
In schizophrenia, cognitive overload is thought to reflect an inability to suppress non-salient information, a process which is studied using prepulse inhibition (PPI) of the startle response. PPI is reduced in schizophrenia and routinely tested in animal models and preclinical trials of antipsychotic drugs. However, the underlying neuronal circuitry is not well understood. We used a novel genetic screen in larval zebrafish to reveal the molecular identity of neurons that are required for PPI in fish and mice. Ablation or optogenetic silencing of neurons with developmental expression of the transcription factor genomic screen homeobox 1 (gsx1) produced profound defects in PPI in zebrafish, and PPI was similarly impaired in Gsx1 knockout mice. Gsx1-expressing neurons reside in the dorsal brainstem and form synapses closely apposed to neurons that initiate the startle response. Surprisingly, brainstem Gsx1 neurons are primarily glutamatergic despite their role in a functionally inhibitory pathway. As Gsx1 has an important role in regulating interneuron development in the forebrain, these findings reveal a molecular link between control of interneuron specification and circuits that gate sensory information across brain regions.
Collapse
Affiliation(s)
- Sadie A. Bergeron
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Nicole Carrier
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Grace H. Li
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Sohyun Ahn
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Harold A. Burgess
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA,6 Center Drive, Building 6B, Rm 3B308, Bethesda, MD 20892, , tel: 301-402-6018; fax: 301-496-0243
| |
Collapse
|
211
|
Zhang P, Ha T, Larouche M, Swanson D, Goldowitz D. Kruppel-Like Factor 4 Regulates Granule Cell Pax6 Expression and Cell Proliferation in Early Cerebellar Development. PLoS One 2015; 10:e0134390. [PMID: 26226504 PMCID: PMC4520560 DOI: 10.1371/journal.pone.0134390] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Accepted: 07/09/2015] [Indexed: 11/19/2022] Open
Abstract
Kruppel-like factor 4 (Klf4) is a transcription factor that regulates many important cellular processes in stem cell biology, cancer, and development. We used histological and molecular methods to study the expression of Klf4 in embryonic development of the normal and Klf4 knockout cerebellum. We find that Klf4 is expressed strongly in early granule cell progenitor development but tails-off considerably by the end of embryonic development. Klf4 is also co-expressed with Pax6 in these cells. In the Klf4-null mouse, which is perinatal lethal, Klf4 positively regulates Pax6 expression and regulates the proliferation of neuronal progenitors in the rhombic lip, external granular layer and the neuroepithelium. This paper is the first to describe a role for Klf4 in the cerebellum and provides insight into this gene’s function in neuronal development.
Collapse
Affiliation(s)
- Peter Zhang
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
| | - Thomas Ha
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
| | - Matt Larouche
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
| | - Douglas Swanson
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
| | - Dan Goldowitz
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
- * E-mail:
| |
Collapse
|
212
|
Zindy F, Lee Y, Kawauchi D, Ayrault O, Merzoug LB, Li Y, McKinnon PJ, Roussel MF. Dicer Is Required for Normal Cerebellar Development and to Restrain Medulloblastoma Formation. PLoS One 2015; 10:e0129642. [PMID: 26091048 PMCID: PMC4474721 DOI: 10.1371/journal.pone.0129642] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 05/11/2015] [Indexed: 11/18/2022] Open
Abstract
Dicer, a ribonuclease III enzyme, is required for the maturation of microRNAs. To assess its role in cerebellar and medulloblastoma development, we genetically deleted Dicer in Nestin-positive neural progenitors and in mice lacking one copy for the Sonic Hedgehog receptor, Patched 1. We found that conditional loss of Dicer in mouse neural progenitors induced massive Trp53-independent apoptosis in all proliferative zones of the brain and decreased proliferation of cerebellar granule progenitors at embryonic day 15.5 leading to abnormal cerebellar development and perinatal lethality. Loss of one copy of Dicer significantly accelerated the formation of mouse medulloblastoma of the Sonic Hedgehog subgroup in Patched1-heterozygous mice. We conclude that Dicer is required for proper cerebellar development, and to restrain medulloblastoma formation.
Collapse
Affiliation(s)
- Frederique Zindy
- Department of Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, TN, United States of America
| | - Youngsoo Lee
- Department of Genetics, St. Jude Children’s Research Hospital, Memphis, TN, United States of America
| | - Daisuke Kawauchi
- Department of Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, TN, United States of America
| | - Olivier Ayrault
- Department of Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, TN, United States of America
| | - Leila Ben Merzoug
- Department of Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, TN, United States of America
| | - Yang Li
- Department of Genetics, St. Jude Children’s Research Hospital, Memphis, TN, United States of America
| | - Peter J. McKinnon
- Department of Genetics, St. Jude Children’s Research Hospital, Memphis, TN, United States of America
| | - Martine F. Roussel
- Department of Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, TN, United States of America
- * E-mail:
| |
Collapse
|
213
|
Characterization of the transcriptome of nascent hair cells and identification of direct targets of the Atoh1 transcription factor. J Neurosci 2015; 35:5870-83. [PMID: 25855195 DOI: 10.1523/jneurosci.5083-14.2015] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Hair cells are sensory receptors for the auditory and vestibular system in vertebrates. The transcription factor Atoh1 is both necessary and sufficient for the differentiation of hair cells, and is strongly upregulated during hair-cell regeneration in nonmammalian vertebrates. To identify genes involved in hair cell development and function, we performed RNA-seq profiling of purified Atoh1-expressing hair cells from the neonatal mouse cochlea. We identified >600 enriched transcripts in cochlear hair cells, of which 90% have not been previously shown to be expressed in hair cells. We identified 233 of these hair cell genes as candidates to be directly regulated by Atoh1 based on the presence of Atoh1 binding sites in their regulatory regions and by analyzing Atoh1 ChIP-seq datasets from the cerebellum and small intestine. We confirmed 10 of these genes as being direct Atoh1 targets in the cochlea by ChIP-PCR. The identification of candidate Atoh1 target genes is a first step in identifying gene regulatory networks for hair-cell development and may inform future studies on the potential role of Atoh1 in mammalian hair cell regeneration.
Collapse
|
214
|
Legué E, Riedel E, Joyner AL. Clonal analysis reveals granule cell behaviors and compartmentalization that determine the folded morphology of the cerebellum. Development 2015; 142:1661-71. [PMID: 25834018 DOI: 10.1242/dev.120287] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 03/09/2015] [Indexed: 11/20/2022]
Abstract
The mammalian cerebellum consists of folds of different sizes and shapes that house distinct neural circuits. A crucial factor underlying foliation is the generation of granule cells (gcs), the most numerous neuron type in the brain. We used clonal analysis to uncover global as well as folium size-specific cellular behaviors that underlie cerebellar morphogenesis. Unlike most neural precursors, gc precursors divide symmetrically, accounting for their massive expansion. We found that oriented cell divisions underlie an overall anteroposteriorly polarized growth of the cerebellum and gc clone geometry. Clone geometry is further refined by mediolateral oriented migration and passive dispersion of differentiating gcs. Most strikingly, the base of each fissure acts as a boundary for gc precursor dispersion, which we propose allows each folium to be regulated as a developmental unit. Indeed, the geometry and size of clones in long and short folia are distinct. Moreover, in engrailed 1/2 mutants with shorter folia, clone cell number and geometry are most similar to clones in short folia of wild-type mice. Thus, the cerebellum has a modular mode of development that allows the plane of cell division and number of divisions to be differentially regulated to ensure that the appropriate number of cells are partitioned into each folium.
Collapse
Affiliation(s)
- Emilie Legué
- Department of Developmental Biology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Elyn Riedel
- Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Alexandra L Joyner
- Department of Developmental Biology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| |
Collapse
|
215
|
Tong KK, Ma TC, Kwan KM. BMP/Smad signaling and embryonic cerebellum development: Stem cell specification and heterogeneity of anterior rhombic lip. Dev Growth Differ 2015; 57:121-34. [DOI: 10.1111/dgd.12198] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 12/15/2014] [Accepted: 01/05/2015] [Indexed: 01/16/2023]
Affiliation(s)
- Ka Kui Tong
- School of Life Sciences; The Chinese University of Hong Kong; Hong Kong China
| | - Tsz Ching Ma
- School of Life Sciences; The Chinese University of Hong Kong; Hong Kong China
| | - Kin Ming Kwan
- School of Life Sciences; The Chinese University of Hong Kong; Hong Kong China
- RGC-AoE Centre for Organelle Biogenesis and Function; The Chinese University of Hong Kong; Hong Kong China
- Partner State Key Laboratory of Agrobiotechnology (CUHK); The Chinese University of Hong Kong; Hong Kong China
| |
Collapse
|
216
|
Willaredt MA, Schlüter T, Nothwang HG. The gene regulatory networks underlying formation of the auditory hindbrain. Cell Mol Life Sci 2015; 72:519-535. [PMID: 25332098 PMCID: PMC11113740 DOI: 10.1007/s00018-014-1759-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/24/2014] [Accepted: 10/09/2014] [Indexed: 01/28/2023]
Abstract
Development and evolution of auditory hindbrain nuclei are two major unsolved issues in hearing research. Recent characterization of transgenic mice identified the rhombomeric origins of mammalian auditory nuclei and unraveled genes involved in their formation. Here, we provide an overview on these data by assembling them into rhombomere-specific gene regulatory networks (GRNs), as they underlie developmental and evolutionary processes. To explore evolutionary mechanisms, we compare the GRNs operating in the mammalian auditory hindbrain with data available from the inner ear and other vertebrate groups. Finally, we propose that the availability of genomic sequences from all major vertebrate taxa and novel genetic techniques for non-model organisms provide an unprecedented opportunity to investigate development and evolution of the auditory hindbrain by comparative molecular approaches. The dissection of the molecular mechanisms leading to auditory structures will also provide an important framework for auditory processing disorders, a clinical problem difficult to tackle so far. These data will, therefore, foster basic and clinical hearing research alike.
Collapse
Affiliation(s)
- Marc A Willaredt
- Neurogenetics group, Center of Excellence Hearing4All, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
| | - Tina Schlüter
- Neurogenetics group, Center of Excellence Hearing4All, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany
| | - Hans Gerd Nothwang
- Neurogenetics group, Center of Excellence Hearing4All, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
- Research Center for Neurosensory Science, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
| |
Collapse
|
217
|
The emerging framework of mammalian auditory hindbrain development. Cell Tissue Res 2015; 361:33-48. [DOI: 10.1007/s00441-014-2110-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 12/22/2014] [Indexed: 02/06/2023]
|
218
|
Self-organization of polarized cerebellar tissue in 3D culture of human pluripotent stem cells. Cell Rep 2015; 10:537-50. [PMID: 25640179 DOI: 10.1016/j.celrep.2014.12.051] [Citation(s) in RCA: 477] [Impact Index Per Article: 47.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 11/17/2014] [Accepted: 12/22/2014] [Indexed: 12/14/2022] Open
Abstract
During cerebellar development, the main portion of the cerebellar plate neuroepithelium gives birth to Purkinje cells and interneurons, whereas the rhombic lip, the germinal zone at its dorsal edge, generates granule cells and cerebellar nuclei neurons. However, it remains elusive how these components cooperate to form the intricate cerebellar structure. Here, we found that a polarized cerebellar structure self-organizes in 3D human embryonic stem cell (ESC) culture. The self-organized neuroepithelium differentiates into electrophysiologically functional Purkinje cells. The addition of fibroblast growth factor 19 (FGF19) promotes spontaneous generation of dorsoventrally polarized neural-tube-like structures at the level of the cerebellum. Furthermore, addition of SDF1 and FGF19 promotes the generation of a continuous cerebellar plate neuroepithelium with rhombic-lip-like structure at one end and a three-layer cytoarchitecture similar to the embryonic cerebellum. Thus, human-ESC-derived cerebellar progenitors exhibit substantial self-organizing potential for generating a polarized structure reminiscent of the early human cerebellum at the first trimester.
Collapse
|
219
|
Marzban H, Del Bigio MR, Alizadeh J, Ghavami S, Zachariah RM, Rastegar M. Cellular commitment in the developing cerebellum. Front Cell Neurosci 2015; 8:450. [PMID: 25628535 PMCID: PMC4290586 DOI: 10.3389/fncel.2014.00450] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 12/12/2014] [Indexed: 12/11/2022] Open
Abstract
The mammalian cerebellum is located in the posterior cranial fossa and is critical for motor coordination and non-motor functions including cognitive and emotional processes. The anatomical structure of cerebellum is distinct with a three-layered cortex. During development, neurogenesis and fate decisions of cerebellar primordium cells are orchestrated through tightly controlled molecular events involving multiple genetic pathways. In this review, we will highlight the anatomical structure of human and mouse cerebellum, the cellular composition of developing cerebellum, and the underlying gene expression programs involved in cell fate commitments in the cerebellum. A critical evaluation of the cell death literature suggests that apoptosis occurs in ~5% of cerebellar cells, most shortly after mitosis. Apoptosis and cellular autophagy likely play significant roles in cerebellar development, we provide a comprehensive discussion of their role in cerebellar development and organization. We also address the possible function of unfolded protein response in regulation of cerebellar neurogenesis. We discuss recent advancements in understanding the epigenetic signature of cerebellar compartments and possible connections between DNA methylation, microRNAs and cerebellar neurodegeneration. Finally, we discuss genetic diseases associated with cerebellar dysfunction and their role in the aging cerebellum.
Collapse
Affiliation(s)
- Hassan Marzban
- Department of Human Anatomy and Cell Science, University of Manitoba Winnipeg, MB, Canada
| | - Marc R Del Bigio
- Department of Human Anatomy and Cell Science, University of Manitoba Winnipeg, MB, Canada ; Department of Pathology, University of Manitoba Winnipeg, MB, Canada
| | - Javad Alizadeh
- Department of Human Anatomy and Cell Science, University of Manitoba Winnipeg, MB, Canada
| | - Saeid Ghavami
- Department of Human Anatomy and Cell Science, University of Manitoba Winnipeg, MB, Canada
| | - Robby M Zachariah
- Department of Biochemistry and Medical Genetics, University of Manitoba Winnipeg, MB, Canada ; Regenerative Medicine Program, University of Manitoba Winnipeg, MB, Canada
| | - Mojgan Rastegar
- Department of Biochemistry and Medical Genetics, University of Manitoba Winnipeg, MB, Canada ; Regenerative Medicine Program, University of Manitoba Winnipeg, MB, Canada
| |
Collapse
|
220
|
Abstract
Math1 is the defining molecule of the cerebellar rhombic lip and Pax6 is downstream in the Math1 pathway. In the present study, we discover that Wntless (Wls) is a novel molecular marker of the cells in the interior face of the rhombic lip throughout normal mouse cerebellar development. Wls expression is found complementary to the expression of Math1 and Pax6, which are localized to the exterior face of the rhombic lip. To determine the interaction between these molecules, we examine the loss-of-Math1 or loss-of-Pax6 in the cerebellum, i.e., the Math1-null and Pax6-null (Sey) mutant cerebella. The presence of Wls-positive cells in the Math1-null rhombic lip indicates that Wls expression is independent of Math1. In the Sey mutant cerebellum, there is an expansion of Wls-expressing cells into regions that are normally colonized by Pax6-expressing cells. The ectopic expression of Wls in the Pax6-null cerebellum suggests a negative interaction between Wls-expressing cells and Pax6-positive cells. These findings suggest that the rhombic lip is dynamically patterned by the expression of Wls, Math1, and Pax6. We also examine five rhombic lip cell markers (Wls, Math1, Pax6, Lmx1a, and Tbr2) to identify four molecularly distinct compartments in the rhombic lip during cerebellar development. The existence of spatial compartmentation in the rhombic lip and the interplay between Wls, Math1, and Pax6 in the rhombic lip provides novel views of early cerebellar development.
Collapse
|
221
|
Sathyamurthy A, Yin DM, Barik A, Shen C, Bean JC, Figueiredo D, She JX, Xiong WC, Mei L. ERBB3-mediated regulation of Bergmann glia proliferation in cerebellar lamination. Development 2015; 142:522-32. [PMID: 25564653 DOI: 10.1242/dev.115931] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cortical lamination is crucial for the assembly of cerebellar circuitry. In this process, granule neurons (GNs) migrate along Bergmann glia (BG), which are specialized astroglial cells, from the external granule layer to the internal granule layer. However, the molecular mechanisms underlying BG development are not well understood. Here, we show that GFAP::Cre;Erbb3(F/F) mice, which lack Erbb3 in both radial glia and neurons, exhibit impairments in balance and motor coordination. Cerebellar lamination is aberrant, with misplaced Purkinje neurons and GN clusters. These phenotypes were not observed in Math1::CreER(T2);Erbb3(F/F) mice, where the Erbb3 gene was deleted in GNs, suggesting involvement of non-neuronal Erbb3 in cerebellar lamination. Mechanistic studies indicate that ERBB3 is crucial for the proliferation of BG, which are required for GN migration. These observations identify a crucial role for ERBB3 in cerebellar lamination and reveal a novel mechanism that regulates BG development.
Collapse
Affiliation(s)
- Anupama Sathyamurthy
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA
| | - Dong-Min Yin
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA
| | - Arnab Barik
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA
| | - Chengyong Shen
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA Charlie Norwood VA Medical Center, Augusta, GA 30904, USA
| | - Jonathan C Bean
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA
| | - Dwight Figueiredo
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA Charlie Norwood VA Medical Center, Augusta, GA 30904, USA
| | - Jin-Xiong She
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA
| | - Wen-Cheng Xiong
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA Charlie Norwood VA Medical Center, Augusta, GA 30904, USA Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA
| | - Lin Mei
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA Charlie Norwood VA Medical Center, Augusta, GA 30904, USA Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA
| |
Collapse
|
222
|
Butts T, Green MJ, Wingate RJT. Development of the cerebellum: simple steps to make a 'little brain'. Development 2014; 141:4031-41. [PMID: 25336734 DOI: 10.1242/dev.106559] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The cerebellum is a pre-eminent model for the study of neurogenesis and circuit assembly. Increasing interest in the cerebellum as a participant in higher cognitive processes and as a locus for a range of disorders and diseases make this simple yet elusive structure an important model in a number of fields. In recent years, our understanding of some of the more familiar aspects of cerebellar growth, such as its territorial allocation and the origin of its various cell types, has undergone major recalibration. Furthermore, owing to its stereotyped circuitry across a range of species, insights from a variety of species have contributed to an increasingly rich picture of how this system develops. Here, we review these recent advances and explore three distinct aspects of cerebellar development - allocation of the cerebellar anlage, the significance of transit amplification and the generation of neuronal diversity - each defined by distinct regulatory mechanisms and each with special significance for health and disease.
Collapse
Affiliation(s)
- Thomas Butts
- MRC Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK School of Biological and Chemical Sciences, Queen Mary, University of London, London E1 4NS, UK
| | - Mary J Green
- National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
| | - Richard J T Wingate
- MRC Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK
| |
Collapse
|
223
|
Tsai MY, Lu YF, Liu YH, Lien HW, Huang CJ, Wu JL, Hwang SPL. Modulation of p53 and met expression by Krüppel-like factor 8 regulates zebrafish cerebellar development. Dev Neurobiol 2014; 75:908-26. [PMID: 25528982 DOI: 10.1002/dneu.22258] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/04/2014] [Accepted: 12/15/2014] [Indexed: 12/20/2022]
Abstract
Krüppel-like factor 8 (Klf8) is a zinc-finger transcription factor implicated in cell proliferation, and cancer cell survival and invasion; however, little is known about its role in normal embryonic development. Here, we show that Klf8 is required for normal cerebellar development in zebrafish embryos. Morpholino knockdown of klf8 resulted in abnormal cerebellar primordium morphology and the induction of p53 in the brain region at 24 hours post-fertilization (hpf). Both p53-dependent reduction of cell proliferation and augmentation of apoptosis were observed in the cerebellar anlage of 24 hpf-klf8 morphants. In klf8 morphants, expression of ptf1a in the ventricular zone was decreased from 48 to 72 hpf; on the other hand, expression of atohla in the upper rhombic lip was unaffected. Consistent with this finding, Purkinje cell development was perturbed and granule cell number was reduced in 72 hpf-klf8 morphants; co-injection of p53 MO(sp) or klf8 mRNA substantially rescued development of cerebellar Purkinje cells in klf8 morphants. Hepatocyte growth factor/Met signaling is known to regulate cerebellar development in zebrafish and mouse. We observed decreased met expression in the tectum and rhombomere 1 of 24 hpf-klf8 morphants, which was largely rescued by co-injection with klf8 mRNA. Moreover, co-injection of met mRNA substantially rescued formation of Purkinje cells in klf8 morphants at 72 hpf. Together, these results demonstrate that Klf8 modulates expression of p53 and met to maintain ptf1a-expressing neuronal progenitors, which are required for the appropriate development of cerebellar Purkinje and granule cells in zebrafish embryos.
Collapse
Affiliation(s)
- Ming-Yuan Tsai
- Graduate Institute of Life Sciences, National Defense Medical Center, Neihu, Taipei, Taiwan, 114, Republic of China
| | - Yu-Fen Lu
- Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, Taiwan, 115, Republic of China
| | - Yu-Hsiu Liu
- Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, Taiwan, 115, Republic of China.,Institute of Zoology, National Taiwan University, Taipei, Taiwan, 10617, Republic of China
| | - Huang-Wei Lien
- Institute of Biological Chemistry, Academia Sinica, Nankang, Taipei, Taiwan, 115, Republic of China
| | - Chang-Jen Huang
- Graduate Institute of Life Sciences, National Defense Medical Center, Neihu, Taipei, Taiwan, 114, Republic of China.,Institute of Biological Chemistry, Academia Sinica, Nankang, Taipei, Taiwan, 115, Republic of China
| | - Jen-Leih Wu
- Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, Taiwan, 115, Republic of China
| | - Sheng-Ping L Hwang
- Graduate Institute of Life Sciences, National Defense Medical Center, Neihu, Taipei, Taiwan, 114, Republic of China.,Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, Taiwan, 115, Republic of China
| |
Collapse
|
224
|
Tiberi L, Bonnefont J, van den Ameele J, Le Bon SD, Herpoel A, Bilheu A, Baron BW, Vanderhaeghen P. A BCL6/BCOR/SIRT1 complex triggers neurogenesis and suppresses medulloblastoma by repressing Sonic Hedgehog signaling. Cancer Cell 2014; 26:797-812. [PMID: 25490446 DOI: 10.1016/j.ccell.2014.10.021] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 07/27/2014] [Accepted: 10/30/2014] [Indexed: 12/21/2022]
Abstract
Disrupted differentiation during development can lead to oncogenesis, but the underlying mechanisms remain poorly understood. Here we identify BCL6, a transcriptional repressor and lymphoma oncoprotein, as a pivotal factor required for neurogenesis and tumor suppression of medulloblastoma (MB). BCL6 is necessary for and capable of preventing the development of GNP-derived MB in mice, and can block the growth of human MB cells in vitro. BCL6 neurogenic and oncosuppressor effects rely on direct transcriptional repression of Gli1 and Gli2 effectors of the SHH pathway, through recruitment of BCOR corepressor and SIRT1 deacetylase. Our findings identify the BCL6/BCOR/SIRT1 complex as a potent repressor of the SHH pathway in normal and oncogenic neural development, with direct diagnostic and/or therapeutic relevance for SHH MB.
Collapse
Affiliation(s)
- Luca Tiberi
- Université Libre de Bruxelles (ULB), Institute for Interdisciplinary Research (IRIBHM), and ULB Institute of Neuroscience (UNI), 808 Route de Lennik, 1070 Brussels, Belgium
| | - Jérôme Bonnefont
- Université Libre de Bruxelles (ULB), Institute for Interdisciplinary Research (IRIBHM), and ULB Institute of Neuroscience (UNI), 808 Route de Lennik, 1070 Brussels, Belgium
| | - Jelle van den Ameele
- Université Libre de Bruxelles (ULB), Institute for Interdisciplinary Research (IRIBHM), and ULB Institute of Neuroscience (UNI), 808 Route de Lennik, 1070 Brussels, Belgium
| | - Serge-Daniel Le Bon
- Université Libre de Bruxelles (ULB), Institute for Interdisciplinary Research (IRIBHM), and ULB Institute of Neuroscience (UNI), 808 Route de Lennik, 1070 Brussels, Belgium
| | - Adèle Herpoel
- Université Libre de Bruxelles (ULB), Institute for Interdisciplinary Research (IRIBHM), and ULB Institute of Neuroscience (UNI), 808 Route de Lennik, 1070 Brussels, Belgium
| | - Angéline Bilheu
- Université Libre de Bruxelles (ULB), Institute for Interdisciplinary Research (IRIBHM), and ULB Institute of Neuroscience (UNI), 808 Route de Lennik, 1070 Brussels, Belgium
| | - Beverly W Baron
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Pierre Vanderhaeghen
- Université Libre de Bruxelles (ULB), Institute for Interdisciplinary Research (IRIBHM), and ULB Institute of Neuroscience (UNI), 808 Route de Lennik, 1070 Brussels, Belgium; Walloon Excellence in Life Sciences and Biotechnology (WELBIO), Université Libre de Bruxelles, 808 Route de Lennik, 1070 Brussels, Belgium.
| |
Collapse
|
225
|
Generation of Atoh1-rtTA transgenic mice: a tool for inducible gene expression in hair cells of the inner ear. Sci Rep 2014; 4:6885. [PMID: 25363458 PMCID: PMC4217099 DOI: 10.1038/srep06885] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 10/13/2014] [Indexed: 11/09/2022] Open
Abstract
Atoh1 is a basic helix-loop-helix transcription factor that controls differentiation of hair cells (HCs) in the inner ear and its enhancer region has been used to create several HC-specific mouse lines. We generated a transgenic tetracycline-inducible mouse line (called Atoh1-rtTA) using the Atoh1 enhancer to drive expression of the reverse tetracycline transactivator (rtTA) protein and human placental alkaline phosphatase. Presence of the transgene was confirmed by alkaline phosphatase staining and rtTA activity was measured using two tetracycline operator (TetO) reporter alleles with doxycycline administered between postnatal days 0–3. This characterization of five founder lines demonstrated that Atoh1-rtTA is expressed in the majority of cochlear and utricular HCs. Although the tetracycline-inducible system is thought to produce transient changes in gene expression, reporter positive HCs were still observed at 6 weeks of age. To confirm that Atoh1-rtTA activity was specific to Atoh1-expressing cells, we also analyzed the cerebellum and found rtTA-driven reporter expression in cerebellar granule neuron precursor cells. The Atoh1-rtTA mouse line provides a powerful tool for the field and can be used in combination with other existing Cre recombinase mouse lines to manipulate expression of multiple genes at different times in the same animal.
Collapse
|
226
|
Cai T, Groves AK. The Role of Atonal Factors in Mechanosensory Cell Specification and Function. Mol Neurobiol 2014; 52:1315-1329. [PMID: 25339580 DOI: 10.1007/s12035-014-8925-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 10/07/2014] [Indexed: 10/24/2022]
Abstract
Atonal genes are basic helix-loop-helix transcription factors that were first identified as regulating the formation of mechanoreceptors and photoreceptors in Drosophila. Isolation of vertebrate homologs of atonal genes has shown these transcription factors to play diverse roles in the development of neurons and their progenitors, gut epithelial cells, and mechanosensory cells in the inner ear and skin. In this article, we review the molecular function and regulation of atonal genes and their targets, with particular emphasis on the function of Atoh1 in the development, survival, and function of hair cells of the inner ear. We discuss cell-extrinsic signals that induce Atoh1 expression and the transcriptional networks that regulate its expression during development. Finally, we discuss recent work showing how identification of Atoh1 target genes in the cerebellum, spinal cord, and gut can be used to propose candidate Atoh1 targets in tissues such as the inner ear where cell numbers and biochemical material are limiting.
Collapse
Affiliation(s)
- Tiantian Cai
- Program in Developmental Biology, Baylor College of Medicine, Houston, USA
| | - Andrew K Groves
- Program in Developmental Biology, Baylor College of Medicine, Houston, USA. .,Department of Neuroscience, Baylor College of Medicine, Houston, USA. .,Department of Molecular and Human Genetics, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX, 77030, USA.
| |
Collapse
|
227
|
Ha T, Swanson D, Larouche M, Glenn R, Weeden D, Zhang P, Hamre K, Langston M, Phillips C, Song M, Ouyang Z, Chesler E, Duvvurru S, Yordanova R, Cui Y, Campbell K, Ricker G, Phillips C, Homayouni R, Goldowitz D. CbGRiTS: cerebellar gene regulation in time and space. Dev Biol 2014; 397:18-30. [PMID: 25446528 DOI: 10.1016/j.ydbio.2014.09.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 08/23/2014] [Accepted: 09/27/2014] [Indexed: 01/09/2023]
Abstract
The mammalian CNS is one of the most complex biological systems to understand at the molecular level. The temporal information from time series transcriptome analysis can serve as a potent source of associative information between developmental processes and regulatory genes. Here, we introduce a new transcriptome database called, Cerebellar Gene Regulation in Time and Space (CbGRiTS). This dataset is populated with transcriptome data across embryonic and postnatal development from two standard mouse strains, C57BL/6J and DBA/2J, several recombinant inbred lines and cerebellar mutant strains. Users can evaluate expression profiles across cerebellar development in a deep time series with graphical interfaces for data exploration and link-out to anatomical expression databases. We present three analytical approaches that take advantage of specific aspects of the time series for transcriptome analysis. We demonstrate the use of CbGRiTS dataset as a community resource to explore patterns of gene expression and develop hypotheses concerning gene regulatory networks in brain development.
Collapse
Affiliation(s)
- Thomas Ha
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, Canada V5Z 4H4
| | - Douglas Swanson
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, Canada V5Z 4H4
| | - Matt Larouche
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, Canada V5Z 4H4
| | - Randy Glenn
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, Canada V5Z 4H4
| | - Dave Weeden
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, Canada V5Z 4H4
| | - Peter Zhang
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, Canada V5Z 4H4
| | - Kristin Hamre
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Michael Langston
- Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, TN, USA
| | - Charles Phillips
- Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, TN, USA
| | - Mingzhou Song
- Department of Computer Science, New Mexico State University, Las Cruces, NM, USA
| | - Zhengyu Ouyang
- Department of Computer Science, New Mexico State University, Las Cruces, NM, USA
| | | | | | | | - Yan Cui
- Department of Molecular Science, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Kate Campbell
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, Canada V5Z 4H4
| | - Greg Ricker
- Department of Biology, Bowdoin College, Brunswick, ME, USA
| | - Carey Phillips
- Department of Biology, Bowdoin College, Brunswick, ME, USA
| | - Ramin Homayouni
- Bioinformatics Program, Department of Biology, University of Memphis, Memphis, TN, USA
| | - Dan Goldowitz
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, Canada V5Z 4H4.
| |
Collapse
|
228
|
Brun SN, Markant SL, Esparza LA, Garcia G, Terry D, Huang JM, Pavlyukov MS, Li XN, Grant GA, Crawford JR, Levy ML, Conway EM, Smith LH, Nakano I, Berezov A, Greene MI, Wang Q, Wechsler-Reya RJ. Survivin as a therapeutic target in Sonic hedgehog-driven medulloblastoma. Oncogene 2014; 34:3770-9. [PMID: 25241898 PMCID: PMC4369477 DOI: 10.1038/onc.2014.304] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 07/22/2014] [Accepted: 07/31/2014] [Indexed: 12/31/2022]
Abstract
Medulloblastoma (MB) is a highly malignant brain tumor that occurs primarily in children. Although surgery, radiation and high-dose chemotherapy have led to increased survival, many MB patients still die from their disease, and patients who survive suffer severe long-term side effects as a consequence of treatment. Thus, more effective and less toxic therapies for MB are critically important. Development of such therapies depends in part on identification of genes that are necessary for growth and survival of tumor cells. Survivin is an inhibitor of apoptosis protein that regulates cell cycle progression and resistance to apoptosis, is frequently expressed in human MB and when expressed at high levels predicts poor clinical outcome. Therefore, we hypothesized that Survivin may have a critical role in growth and survival of MB cells and that targeting it may enhance MB therapy. Here we show that Survivin is overexpressed in tumors from patched (Ptch) mutant mice, a model of Sonic hedgehog (SHH)-driven MB. Genetic deletion of survivin in Ptch mutant tumor cells significantly inhibits proliferation and causes cell cycle arrest. Treatment with small-molecule antagonists of Survivin impairs proliferation and survival of both murine and human MB cells. Finally, Survivin antagonists impede growth of MB cells in vivo. These studies highlight the importance of Survivin in SHH-driven MB, and suggest that it may represent a novel therapeutic target in patients with this disease.
Collapse
Affiliation(s)
- S N Brun
- 1] Tumor Initiation and Maintenance Program, National Cancer Institute (NCI)-Designated Cancer Center, Sanford-Burnham Medical Research Institute (SBMRI), La Jolla, CA, USA [2] Sanford Consortium for Regenerative Medicine, La Jolla, CA, USA [3] Department of Pharmacology and Cancer Biology, Duke University, Durham, NC, USA
| | - S L Markant
- 1] Tumor Initiation and Maintenance Program, National Cancer Institute (NCI)-Designated Cancer Center, Sanford-Burnham Medical Research Institute (SBMRI), La Jolla, CA, USA [2] Sanford Consortium for Regenerative Medicine, La Jolla, CA, USA [3] Department of Pharmacology and Cancer Biology, Duke University, Durham, NC, USA
| | - L A Esparza
- 1] Tumor Initiation and Maintenance Program, National Cancer Institute (NCI)-Designated Cancer Center, Sanford-Burnham Medical Research Institute (SBMRI), La Jolla, CA, USA [2] Sanford Consortium for Regenerative Medicine, La Jolla, CA, USA
| | - G Garcia
- Histopathology Core SBMRI, La Jolla, CA, USA
| | - D Terry
- Conrad Prebys Center for Chemical Genomics, SBMRI, Lake Nona, FL, USA
| | - J-M Huang
- Cedars-Sinai Women's Cancer Program at the Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA
| | - M S Pavlyukov
- 1] Department of Neurological Surgery, The Ohio State University, Columbus, OH, USA [2] James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - X-N Li
- Brain Tumor Program, Texas Children's Cancer Center, and Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - G A Grant
- Department of Neurosurgery, Stanford University/Lucile Packard Children's Hospital, Stanford, CA, USA
| | - J R Crawford
- 1] Department of Pediatrics, University of California San Diego, San Diego, CA, USA [2] Departments of Neurosciences, University of California San Diego, San Diego, CA, USA [3] Rady Children's Hospital, San Diego, CA, USA
| | - M L Levy
- 1] Rady Children's Hospital, San Diego, CA, USA [2] Department of Neurosurgery, University of California San Diego, La Jolla, CA, USA
| | - E M Conway
- Centre for Blood Research, Division of Hematology, Department of Medicine, University of British Columbia (UBC), Vancouver, BC, Canada
| | - L H Smith
- 1] Conrad Prebys Center for Chemical Genomics, SBMRI, Lake Nona, FL, USA [2] Cardiopathobiology Program, Sanford Burnham Medical Research Institute, Lake Nona, FL, USA
| | - I Nakano
- 1] Department of Neurological Surgery, The Ohio State University, Columbus, OH, USA [2] James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - A Berezov
- Department of Biomedical Sciences at Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - M I Greene
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Q Wang
- Cedars-Sinai Women's Cancer Program at the Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA
| | - R J Wechsler-Reya
- 1] Tumor Initiation and Maintenance Program, National Cancer Institute (NCI)-Designated Cancer Center, Sanford-Burnham Medical Research Institute (SBMRI), La Jolla, CA, USA [2] Sanford Consortium for Regenerative Medicine, La Jolla, CA, USA [3] Department of Pharmacology and Cancer Biology, Duke University, Durham, NC, USA
| |
Collapse
|
229
|
Abstract
Math1 is the defining molecule of the cerebellar rhombic lip and Pax6 is downstream in the Math1 pathway. In the present study, we discover that Wntless (Wls) is a novel molecular marker of the cells in the interior face of the rhombic lip throughout normal mouse cerebellar development. Wls expression is found complementary to the expression of Math1 and Pax6, which are localized to the exterior face of the rhombic lip. To determine the interaction between these molecules, we examine the loss-of-Math1 or loss-of-Pax6 in the cerebellum, i.e., the Math1-null and Pax6-null (Sey) mutant cerebella. The presence of Wls-positive cells in the Math1-null rhombic lip indicates that Wls expression is independent of Math1. In the Sey mutant cerebellum, there is an expansion of Wls-expressing cells into regions that are normally colonized by Pax6-expressing cells. The ectopic expression of Wls in the Pax6-null cerebellum suggests a negative interaction between Wls-expressing cells and Pax6-positive cells. These findings suggest that the rhombic lip is dynamically patterned by the expression of Wls, Math1, and Pax6. We also examine five rhombic lip cell markers (Wls, Math1, Pax6, Lmx1a, and Tbr2) to identify four molecularly distinct compartments in the rhombic lip during cerebellar development. The existence of spatial compartmentation in the rhombic lip and the interplay between Wls, Math1, and Pax6 in the rhombic lip provides novel views of early cerebellar development.
Collapse
|
230
|
Butts T, Hanzel M, Wingate RJT. Transit amplification in the amniote cerebellum evolved via a heterochronic shift in NeuroD1 expression. Development 2014; 141:2791-5. [PMID: 25005474 DOI: 10.1242/dev.101758] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The cerebellum has evolved elaborate foliation in the amniote lineage as a consequence of extensive Atoh1-mediated transit amplification in an external germinal layer (EGL) comprising granule cell precursors. To explore the evolutionary origin of this layer, we have examined the molecular geography of cerebellar development throughout the life cycle of Xenopus laevis. At metamorphic stages Xenopus displays a superficial granule cell layer that is not proliferative and expresses both Atoh1 and NeuroD1, a marker of postmitotic cerebellar granule cells. Premature misexpression of NeuroD1 in chick partially recapitulates the amphibian condition by suppressing transit amplification. However, unlike in the amphibian, granule cells fail to enter the EGL. Furthermore, misexpression of NeuroD1 once the EGL is established both triggers radial migration and downregulates Atoh1. These results show that the evolution of transit amplification in the EGL required adaptation of NeuroD1, both in the timing of its expression and in its regulatory function, with respect to Atoh1.
Collapse
Affiliation(s)
- Thomas Butts
- MRC Centre for Developmental Neurobiology, King's College London, 4th Floor New Hunt's House, London SE1 1UKL, UK
| | - Michalina Hanzel
- MRC Centre for Developmental Neurobiology, King's College London, 4th Floor New Hunt's House, London SE1 1UKL, UK
| | - Richard J T Wingate
- MRC Centre for Developmental Neurobiology, King's College London, 4th Floor New Hunt's House, London SE1 1UKL, UK
| |
Collapse
|
231
|
Shh signaling protects Atoh1 from degradation mediated by the E3 ubiquitin ligase Huwe1 in neural precursors. Dev Cell 2014; 29:649-61. [PMID: 24960692 DOI: 10.1016/j.devcel.2014.05.014] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 05/16/2014] [Accepted: 05/19/2014] [Indexed: 01/31/2023]
Abstract
Signaling networks controlled by Sonic hedgehog (SHH) and the transcription factor Atoh1 regulate the proliferation and differentiation of cerebellar granule neuron progenitors (GNPs). Deregulations in those developmental processes lead to medulloblastoma formation, the most common malignant brain tumor in childhood. Although the protein Atoh1 is a key factor during both cerebellar development and medulloblastoma formation, up-to-date detailed mechanisms underlying its function and regulation have remained poorly understood. Here, we report that SHH regulates Atoh1 stability by preventing its phosphodependent degradation by the E3 ubiquitin ligase Huwe1. Our results reveal that SHH and Atoh1 contribute to a positive autoregulatory loop promoting neuronal precursor expansion. Consequently, Huwe1 loss in mouse SHH medulloblastoma illustrates the disruption of this developmental mechanism in cancer. Hence, the crosstalk between SHH signaling and Atoh1 during cerebellar development highlights a collaborative network that could be further targeted in medulloblastoma.
Collapse
|
232
|
Mulherkar S, Uddin MD, Couvillon AD, Sillitoe RV, Tolias KF. The small GTPases RhoA and Rac1 regulate cerebellar development by controlling cell morphogenesis, migration and foliation. Dev Biol 2014; 394:39-53. [PMID: 25128586 DOI: 10.1016/j.ydbio.2014.08.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 08/06/2014] [Indexed: 12/22/2022]
Abstract
The small GTPases RhoA and Rac1 are key cytoskeletal regulators that function in a mutually antagonistic manner to control the migration and morphogenesis of a broad range of cell types. However, their role in shaping the cerebellum, a unique brain structure composed of an elaborate set of folia separated by fissures of different lengths, remains largely unexplored. Here we show that dysregulation of both RhoA and Rac1 signaling results in abnormal cerebellar ontogenesis. Ablation of RhoA from neuroprogenitor cells drastically alters the timing and placement of fissure formation, the migration and positioning of granule and Purkinje cells, the alignment of Bergmann glia, and the integrity of the basement membrane, primarily in the anterior lobules. Furthermore, in the absence of RhoA, granule cell precursors located at the base of fissures fail to undergo cell shape changes required for fissure initiation. Many of these abnormalities can be recapitulated by deleting RhoA specifically from granule cell precursors but not postnatal glia, indicating that RhoA functions in granule cell precursors to control cerebellar morphogenesis. Notably, mice with elevated Rac1 activity due to loss of the Rac1 inhibitors Bcr and Abr show similar anterior cerebellar deficits, including ectopic neurons and defects in fissure formation, Bergmann glia organization and basement membrane integrity. Together, our results suggest that RhoA and Rac1 play indispensable roles in patterning cerebellar morphology.
Collapse
Affiliation(s)
- Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Anthony D Couvillon
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - Roy V Sillitoe
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children׳s Hospital, Houston, TX 77030, USA; Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kimberley F Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, M.S. BCM 295, Houston, TX 77030, USA.
| |
Collapse
|
233
|
Rose SJ, Kriener LH, Heinzer AK, Fan X, Raike RS, van den Maagdenberg AMJM, Hess EJ. The first knockin mouse model of episodic ataxia type 2. Exp Neurol 2014; 261:553-62. [PMID: 25109669 DOI: 10.1016/j.expneurol.2014.08.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/07/2014] [Accepted: 08/01/2014] [Indexed: 12/28/2022]
Abstract
Episodic ataxia type 2 (EA2) is an autosomal dominant disorder associated with attacks of ataxia that are typically precipitated by stress, ethanol, caffeine or exercise. EA2 is caused by loss-of-function mutations in the CACNA1A gene, which encodes the α1A subunit of the CaV2.1 voltage-gated Ca(2+) channel. To better understand the pathomechanisms of this disorder in vivo, we created the first genetic animal model of EA2 by engineering a mouse line carrying the EA2-causing c.4486T>G (p.F1406C) missense mutation in the orthologous mouse Cacna1a gene. Mice homozygous for the mutated allele exhibit a ~70% reduction in CaV2.1 current density in Purkinje cells, though surprisingly do not exhibit an overt motor phenotype. Mice hemizygous for the knockin allele (EA2/- mice) did exhibit motor dysfunction measurable by rotarod and pole test. Studies using Cre-flox conditional genetics explored the role of cerebellar Purkinje cells or cerebellar granule cells in the poor motor performance of EA2/- mice and demonstrate that manipulation of either cell type alone did not cause poor motor performance. Thus, it is possible that subtle dysfunction arising from multiple cell types is necessary for the expression of certain ataxia syndromes.
Collapse
Affiliation(s)
- Samuel J Rose
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Lisa H Kriener
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Ann K Heinzer
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Xueliang Fan
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Robert S Raike
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Arn M J M van den Maagdenberg
- Department of Human Genetics, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands; Department of Neurology, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands
| | - Ellen J Hess
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| |
Collapse
|
234
|
Benitez SG, Castro AE, Patterson SI, Muñoz EM, Seltzer AM. Hypoxic preconditioning differentially affects GABAergic and glutamatergic neuronal cells in the injured cerebellum of the neonatal rat. PLoS One 2014; 9:e102056. [PMID: 25032984 PMCID: PMC4102512 DOI: 10.1371/journal.pone.0102056] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/13/2014] [Indexed: 12/13/2022] Open
Abstract
In this study we examined cerebellar alterations in a neonatal rat model of hypoxic-ischemic brain injury with or without hypoxic preconditioning (Pc). Between postnatal days 7 and 15, the cerebellum is still undergoing intense cellular proliferation, differentiation and migration, dendritogenesis and synaptogenesis. The expression of glutamate decarboxylase 1 (GAD67) and the differentiation factor NeuroD1 were examined as markers of Purkinje and granule cells, respectively. We applied quantitative immunohistochemistry to sagittal cerebellar slices, and Western blot analysis of whole cerebella obtained from control (C) rats and rats submitted to Pc, hypoxia-ischemia (L) and a combination of both treatments (PcL). We found that either hypoxia-ischemia or Pc perturbed the granule cells in the posterior lobes, affecting their migration and final placement in the internal granular layer. These effects were partially attenuated when the Pc was delivered prior to the hypoxia-ischemia. Interestingly, whole nuclear NeuroD1 levels in Pc animals were comparable to those in the C rats. However, a subset of Purkinje cells that were severely affected by the hypoxic-ischemic insult—showing signs of neuronal distress at the levels of the nucleus, cytoplasm and dendritic arborization—were not protected by Pc. A monoclonal antibody specific for GAD67 revealed a three-band pattern in cytoplasmic extracts from whole P15 cerebella. A ∼110 kDa band, interpreted as a potential homodimer of a truncated form of GAD67, was reduced in Pc and L groups while its levels were close to the control animals in PcL rats. Additionally we demonstrated differential glial responses depending on the treatment, including astrogliosis in hypoxiated cerebella and a selective effect of hypoxia-ischemia on the vimentin-immunolabeled intermediate filaments of the Bergmann glia. Thus, while both glutamatergic and GABAergic cerebellar neurons are compromised by the hypoxic-ischemic insult, the former are protected by a preconditioning hypoxia while the latter are not.
Collapse
Affiliation(s)
- Sergio G Benitez
- Laboratory of Neurobiology: Chronobiology Section, Institute of Histology and Embryology of Mendoza (IHEM), School of Medicine, National University of Cuyo, Mendoza, National Scientific and Technical Research Council (CONICET), National Agency for Scientific and Technological Promotion (ANPCyT), Mendoza, Argentina
| | - Analía E Castro
- Laboratory of Neurobiology: Chronobiology Section, Institute of Histology and Embryology of Mendoza (IHEM), School of Medicine, National University of Cuyo, Mendoza, National Scientific and Technical Research Council (CONICET), National Agency for Scientific and Technological Promotion (ANPCyT), Mendoza, Argentina
| | - Sean I Patterson
- Traumatic and Toxic Lesions in the Nervous System Section, Institute of Histology and Embryology of Mendoza (IHEM), School of Medicine, National University of Cuyo, Mendoza, National Scientific and Technical Research Council (CONICET), National Agency for Scientific and Technological Promotion (ANPCyT), Mendoza, Argentina
| | - Estela M Muñoz
- Laboratory of Neurobiology: Chronobiology Section, Institute of Histology and Embryology of Mendoza (IHEM), School of Medicine, National University of Cuyo, Mendoza, National Scientific and Technical Research Council (CONICET), National Agency for Scientific and Technological Promotion (ANPCyT), Mendoza, Argentina
| | - Alicia M Seltzer
- Neonatal Brain Development Section, Institute of Histology and Embryology of Mendoza (IHEM), School of Medicine, National University of Cuyo, Mendoza, National Scientific and Technical Research Council (CONICET), National Agency for Scientific and Technological Promotion (ANPCyT), Mendoza, Argentina
| |
Collapse
|
235
|
Pohlkamp T, Steller L, May P, Günther T, Schüle R, Frotscher M, Herz J, Bock HH. Generation and characterization of an Nse-CreERT2 transgenic line suitable for inducible gene manipulation in cerebellar granule cells. PLoS One 2014; 9:e100384. [PMID: 24950299 PMCID: PMC4065071 DOI: 10.1371/journal.pone.0100384] [Citation(s) in RCA: 8] [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: 12/20/2013] [Accepted: 05/27/2014] [Indexed: 12/15/2022] Open
Abstract
We created an Nse-CreERT2 mouse line expressing the tamoxifen-inducible CreERT2 recombinase under the control of the neuron-specific enolase (Nse) promoter. By using Cre reporter lines we could show that this Nse-CreERT2 line has recombination activity in the granule cells of all cerebellar lobules as well as in postmitotic granule cell precursors in the external granular layer of the developing cerebellum. A few hippocampal dentate gyrus granule cells showed Cre-mediated recombination as well. Cre activity could be induced in both the developing and adult mouse brain. The established mouse line constitutes a valuable tool to study the function of genes expressed by cerebellar granule cells in the developing and adult brain. In combination with reporter lines it is a useful model to analyze the development and maintenance of the cerebellar architecture including granule cell distribution, migration, and the extension of granule cell fibers in vivo.
Collapse
Affiliation(s)
- Theresa Pohlkamp
- Center for Neuroscience, Department of Neuroanatomy, Albert-Ludwigs-University, Freiburg, Germany
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- * E-mail: (TP); (JH); (HHB)
| | - Laura Steller
- Center for Neuroscience, Department of Neuroanatomy, Albert-Ludwigs-University, Freiburg, Germany
| | - Petra May
- Center for Neuroscience, Department of Neuroanatomy, Albert-Ludwigs-University, Freiburg, Germany
- Clinic for Gastroenterology, Hepatology and Infectiology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Thomas Günther
- Department of Urology, University Hospital Freiburg, Freiburg, Germany
| | - Roland Schüle
- Department of Urology, University Hospital Freiburg, Freiburg, Germany
| | - Michael Frotscher
- Institute for Structural Neurobiology, Center for Molecular Neurobiology, Hamburg, Germany
| | - Joachim Herz
- Center for Neuroscience, Department of Neuroanatomy, Albert-Ludwigs-University, Freiburg, Germany
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- * E-mail: (TP); (JH); (HHB)
| | - Hans H. Bock
- Center for Neuroscience, Department of Neuroanatomy, Albert-Ludwigs-University, Freiburg, Germany
- Clinic for Gastroenterology, Hepatology and Infectiology, Heinrich-Heine-University, Düsseldorf, Germany
- * E-mail: (TP); (JH); (HHB)
| |
Collapse
|
236
|
Specification of spatial identities of cerebellar neuron progenitors by ptf1a and atoh1 for proper production of GABAergic and glutamatergic neurons. J Neurosci 2014; 34:4786-800. [PMID: 24695699 DOI: 10.1523/jneurosci.2722-13.2014] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the cerebellum, the bHLH transcription factors Ptf1a and Atoh1 are expressed in distinct neuroepithelial regions, the ventricular zone (VZ) and the rhombic lip (RL), and are required for producing GABAergic and glutamatergic neurons, respectively. However, it is unclear whether Ptf1a or Atoh1 is sufficient for specifying GABAergic or glutamatergic neuronal fates. To test this, we generated two novel knock-in mouse lines, Ptf1a(Atoh1) and Atoh1(Ptf1a), that are designed to express Atoh1 and Ptf1a ectopically in the VZ and RL, respectively. In Ptf1a(Atoh1) embryos, ectopically Atoh1-expressing VZ cells produced glutamatergic neurons, including granule cells and deep cerebellar nuclei neurons. Correspondingly, in Atoh1(Ptf1a) animals, ectopically Ptf1a-expressing RL cells produced GABAergic populations, such as Purkinje cells and GABAergic interneurons. Consistent results were also obtained from in utero electroporation of Ptf1a or Atoh1 into embryonic cerebella, suggesting that Ptf1a and Atoh1 are essential and sufficient for GABAergic versus glutamatergic specification in the neuroepithelium. Furthermore, birthdating analyses with BrdU in the knock-in mice or with electroporation studies showed that ectopically produced fate-changed neuronal types were generated at temporal schedules closely simulating those of the wild-type RL and VZ, suggesting that the VZ and RL share common temporal information. Observations of knock-in brains as well as electroporated brains revealed that Ptf1a and Atoh1 mutually negatively regulate their expression, probably contributing to formation of non-overlapping neuroepithelial domains. These findings suggest that Ptf1a and Atoh1 specify spatial identities of cerebellar neuron progenitors in the neuroepithelium, leading to appropriate production of GABAergic and glutamatergic neurons, respectively.
Collapse
|
237
|
Characterization of Olig2 expression during cerebellar development. Gene Expr Patterns 2014; 15:1-7. [DOI: 10.1016/j.gep.2014.02.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 02/18/2014] [Accepted: 02/20/2014] [Indexed: 11/24/2022]
|
238
|
Transformation of the cerebellum into more ventral brainstem fates causes cerebellar agenesis in the absence of Ptf1a function. Proc Natl Acad Sci U S A 2014; 111:E1777-86. [PMID: 24733890 DOI: 10.1073/pnas.1315024111] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Model organism studies have demonstrated that cell fate specification decisions play an important role in normal brain development. Their role in human neurodevelopmental disorders, however, is poorly understood, with very few examples described. The cerebellum is an excellent system to study mechanisms of cell fate specification. Although signals from the isthmic organizer are known to specify cerebellar territory along the anterior-posterior axis of the neural tube, the mechanisms establishing the cerebellar anlage along the dorsal-ventral axis are unknown. Here we show that the gene encoding pancreatic transcription factor PTF1A, which is inactivated in human patients with cerebellar agenesis, is required to segregate the cerebellum from more ventral extracerebellar fates. Using genetic fate mapping in mice, we show that in the absence of Ptf1a, cells originating in the cerebellar ventricular zone initiate a more ventral brainstem expression program, including LIM homeobox transcription factor 1 beta and T-cell leukemia homeobox 3. Misspecified cells exit the cerebellar anlage and contribute to the adjacent brainstem or die, leading to cerebellar agenesis in Ptf1a mutants. Our data identify Ptf1a as the first gene involved in the segregation of the cerebellum from the more ventral brainstem. Further, we propose that cerebellar agenesis represents a new, dorsal-to-ventral, cell fate misspecification phenotype in humans.
Collapse
|
239
|
Nakatani T, Minaki Y, Kumai M, Nitta C, Ono Y. The c-Ski family member and transcriptional regulator Corl2/Skor2 promotes early differentiation of cerebellar Purkinje cells. Dev Biol 2014; 388:68-80. [DOI: 10.1016/j.ydbio.2014.01.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 01/16/2014] [Accepted: 01/22/2014] [Indexed: 10/25/2022]
|
240
|
Jaarsma D, van den Berg R, Wulf PS, van Erp S, Keijzer N, Schlager MA, de Graaff E, De Zeeuw CI, Pasterkamp RJ, Akhmanova A, Hoogenraad CC. A role for Bicaudal-D2 in radial cerebellar granule cell migration. Nat Commun 2014; 5:3411. [PMID: 24614806 DOI: 10.1038/ncomms4411] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Accepted: 02/07/2014] [Indexed: 01/20/2023] Open
Abstract
Bicaudal-D (BICD) belongs to an evolutionary conserved family of dynein adaptor proteins. It was first described in Drosophila as an essential factor in fly oogenesis and embryogenesis. Missense mutations in a human BICD homologue, BICD2, have been linked to a dominant mild early onset form of spinal muscular atrophy. Here we further examine the in vivo function of BICD2 in Bicd2 knockout mice. BICD2-deficient mice develop disrupted laminar organization of cerebral cortex and the cerebellum, pointing to impaired radial neuronal migration. Using astrocyte and granule cell specific inactivation of BICD2, we show that the cerebellar migration defect is entirely dependent upon BICD2 expression in Bergmann glia cells. Proteomics analysis reveals that Bicd2 mutant mice have an altered composition of extracellular matrix proteins produced by glia cells. These findings demonstrate an essential non-cell-autonomous role of BICD2 in neuronal cell migration, which might be connected to cargo trafficking pathways in glia cells.
Collapse
Affiliation(s)
- Dick Jaarsma
- 1] Erasmus Medical Center, Department of Neuroscience, 3015 GE Rotterdam, The Netherlands [2]
| | - Robert van den Berg
- 1] Erasmus Medical Center, Department of Neuroscience, 3015 GE Rotterdam, The Netherlands [2] Cell Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands [3]
| | - Phebe S Wulf
- 1] Erasmus Medical Center, Department of Neuroscience, 3015 GE Rotterdam, The Netherlands [2] Cell Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands [3]
| | - Susan van Erp
- Netherlands Institute for Neuroscience, Royal Dutch Academy of Arts & Sciences, 1105 BA Amsterdam, The Netherlands
| | - Nanda Keijzer
- Erasmus Medical Center, Department of Neuroscience, 3015 GE Rotterdam, The Netherlands
| | - Max A Schlager
- Erasmus Medical Center, Department of Neuroscience, 3015 GE Rotterdam, The Netherlands
| | - Esther de Graaff
- 1] Erasmus Medical Center, Department of Neuroscience, 3015 GE Rotterdam, The Netherlands [2] Cell Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Chris I De Zeeuw
- 1] Erasmus Medical Center, Department of Neuroscience, 3015 GE Rotterdam, The Netherlands [2] Netherlands Institute for Neuroscience, Royal Dutch Academy of Arts & Sciences, 1105 BA Amsterdam, The Netherlands
| | - R Jeroen Pasterkamp
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
| | - Anna Akhmanova
- 1] Cell Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands [2] Department of Cell Biology, Erasmus Medical Center, 3015 GE Rotterdam, The Netherlands
| | - Casper C Hoogenraad
- 1] Erasmus Medical Center, Department of Neuroscience, 3015 GE Rotterdam, The Netherlands [2] Cell Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands
| |
Collapse
|
241
|
Green MJ, Myat AM, Emmenegger BA, Wechsler-Reya RJ, Wilson LJ, Wingate RJT. Independently specified Atoh1 domains define novel developmental compartments in rhombomere 1. Development 2014; 141:389-98. [PMID: 24381197 PMCID: PMC3879817 DOI: 10.1242/dev.099119] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The rhombic lip gives rise to neuronal populations that contribute to cerebellar, proprioceptive and interoceptive networks. Cell production depends on the expression of the basic helix-loop-helix (bHLH) transcription factor Atoh1. In rhombomere 1, Atoh1-positive cells give rise to both cerebellar neurons and extra-cerebellar nuclei in ventral hindbrain. The origin of this cellular diversity has previously been attributed to temporal signals rather than spatial patterning. Here, we show that in both chick and mouse the cerebellar Atoh1 precursor pool is partitioned into initially cryptic spatial domains that reflect the activity of two different organisers: an isthmic Atoh1 domain, which gives rise to isthmic nuclei, and the rhombic lip, which generates deep cerebellar nuclei and granule cells. We use a combination of in vitro explant culture, genetic fate mapping and gene overexpression and knockdown to explore the role of isthmic signalling in patterning these domains. We show that an FGF-dependent isthmic Atoh1 domain is the origin of distinct populations of Lhx9-positive neurons in the extra-cerebellar isthmic nuclei. In the cerebellum, ectopic FGF induces proliferation while blockade reduces the length of the cerebellar rhombic lip. FGF signalling is not required for the specification of cerebellar cell types from the rhombic lip and its upregulation inhibits their production. This suggests that although the isthmus regulates the size of the cerebellar anlage, the downregulation of isthmic FGF signals is required for induction of rhombic lip-derived cerebellar neurons.
Collapse
Affiliation(s)
- Mary J Green
- MRC Centre for Developmental Neurobiology, King's College London, 4th floor New Hunt's House, London SE1 1UL, UK
| | | | | | | | | | | |
Collapse
|
242
|
Green MJ, Wingate RJT. Developmental origins of diversity in cerebellar output nuclei. Neural Dev 2014; 9:1. [PMID: 24405572 PMCID: PMC3929244 DOI: 10.1186/1749-8104-9-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 12/23/2013] [Indexed: 12/26/2022] Open
Abstract
Background The functional integration of the cerebellum into a number of different neural systems is governed by the connection of its output axons. In amniotes, the majority of this output is mediated by an evolutionarily diverse array of cerebellar nuclei that, in mice, are derived from the embryonic rhombic lip. To understand the origins of cerebellar nucleus diversity, we have explored how nucleus development is patterned in birds, which notably lack a dentate-like nucleus output to the dorsal thalamus. Results Using targeted in ovo electoroporation of green fluorescent protein (GFP) and red fluorescent protein (RFP) in a variety of combinations and with different conditional enhancers, we show that cerebellar nuclei in chicks are produced, as in the mouse, at the rhombic lip. Furthermore, the comparison of fate-mapped neurons with molecular markers reveals a strict temporal sequence of cell fate allocation in establishing the avian lateral and medial cerebellar nuclei. In contrast to the mouse cerebellum, Lhx9 expression is confined to extracerebellar thalamic afferent nuclei corresponding to the absence, in chicks, of a dentate nucleus. Spatiotemporally targeted over-expression of Lhx9 in chick cerebellar nuclei (recapitulating in part the mammalian expression pattern) results in a loss of distinct nuclear boundaries and a change in axon initial trajectories consistent with a role for Lhx9 specifying targeting. Conclusions Our results confirm the relationship between cell fate and a fine grain temporal patterning at the rhombic lip. This suggests that the lack of a cerebellar output to the dorsal thalamus of birds corresponds with a restricted expression of the LIM-homeodomain gene Lhx9 to earlier born rhombic lip cohorts when compared to mice. The evolution of cerebellar nucleus diversity in amniotes may hence reflect a heterochronic adaptation of gene expression with respect to the sequential production of rhombic lip derivatives resulting in altered axonal targeting.
Collapse
Affiliation(s)
| | - Richard J T Wingate
- MRC Centre for Developmental Neurobiology, King's College London, 4th floor New Hunt's House, London SE1 1UL UK.
| |
Collapse
|
243
|
Tonic activation of Bax primes neural progenitors for rapid apoptosis through a mechanism preserved in medulloblastoma. J Neurosci 2014; 33:18098-108. [PMID: 24227720 DOI: 10.1523/jneurosci.2602-13.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Commitment to survival or apoptosis within expanding progenitor populations poses distinct risks and benefits to the organism. We investigated whether specialized mechanisms regulate apoptosis in mouse neural progenitors and in the progenitor-derived brain tumor medulloblastoma. Here, we identified constitutive activation of proapoptotic Bax, maintained in check by Bcl-xL, as a mechanism for rapid cell death, common to postnatal neural progenitors and medulloblastoma. We found that tonic activation of Bax in cerebellar progenitors, along with sensitivity to DNA damage, was linked to differentiation state. In cerebellar progenitors, active Bax localized to mitochondria, where it was bound to Bcl-xL. Disruption of Bax:Bcl-xL binding by BH3-mimetic ABT 737 caused rapid apoptosis of cerebellar progenitors and primary murine medulloblastoma cells. Conditional deletion of Mcl-1, in contrast, did not cause death of cerebellar progenitors. Our findings identify a mechanism for the sensitivity of brain progenitors to typical anticancer therapies and reveal that this mechanism persists in medulloblastoma, a malignant brain tumor markedly sensitive to radiation and chemotherapy.
Collapse
|
244
|
Abstract
Proneural genes encode evolutionarily conserved basic-helix-loop-helix transcription factors. In Drosophila, proneural genes are required and sufficient to confer a neural identity onto naïve ectodermal cells, inducing delamination and subsequent neuronal differentiation. In vertebrates, proneural genes are expressed in cells that already have a neural identity, but they are still required and sufficient to initiate neurogenesis. In all organisms, proneural genes control neurogenesis by regulating Notch-mediated lateral inhibition and initiating the expression of downstream differentiation genes. The general mode of proneural gene function has thus been elucidated. However, the regulatory mechanisms that spatially and temporally control proneural gene function are only beginning to be deciphered. Understanding how proneural gene function is regulated is essential, as aberrant proneural gene expression has recently been linked to a variety of human diseases-ranging from cancer to neuropsychiatric illnesses and diabetes. Recent insights into proneural gene function in development and disease are highlighted herein.
Collapse
Affiliation(s)
- Carol Huang
- Department of Pediatrics, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Jennifer A Chan
- Department of Pathology & Laboratory Medicine, Southern Alberta Cancer Research Institute, University of Calgary, Calgary, Alberta, Canada.
| | - Carol Schuurmans
- Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.
| |
Collapse
|
245
|
Pak E, Segal RA, Stiles CD. New progenitors NESTIN(g) in the EGL. Nat Neurosci 2013; 16:1710-2. [PMID: 24270268 DOI: 10.1038/nn.3580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ekaterina Pak
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA, and the Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | | | | |
Collapse
|
246
|
Di Bonito M, Glover JC, Studer M. Hox genes and region-specific sensorimotor circuit formation in the hindbrain and spinal cord. Dev Dyn 2013; 242:1348-68. [PMID: 23996673 DOI: 10.1002/dvdy.24055] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 08/29/2013] [Accepted: 08/29/2013] [Indexed: 01/17/2023] Open
Abstract
Homeobox (Hox) genes were originally discovered in the fruit fly Drosophila, where they function through a conserved homeodomain as transcriptional regulators to control embryonic morphogenesis. In vertebrates, 39 Hox genes have been identified and like their Drosophila counterparts they are organized within chromosomal clusters. Hox genes interact with various cofactors, such as the TALE homeodomain proteins, in recognition of consensus sequences within regulatory elements of their target genes. In vertebrates, Hox genes display spatially restricted patterns of expression within the developing hindbrain and spinal cord, and are considered crucial determinants of segmental identity and cell specification along the anterioposterior and dorsoventral axes of the embryo. Here, we review their later roles in the assembly of neuronal circuitry, in stereotypic neuronal migration, axon pathfinding, and topographic connectivity. Importantly, we will put some emphasis on how their early-segmented expression patterns can influence the formation of complex vital hindbrain and spinal cord circuitries.
Collapse
Affiliation(s)
- Maria Di Bonito
- University of Nice-Sophia Antipolis, F-06108, Nice, France; INSERM, iBV, UMR 1091, F-06108, Nice, France
| | | | | |
Collapse
|
247
|
Affiliation(s)
| | - Richard Hawkes
- Department of Cell Biology and Anatomy, Genes and Development Research Group and Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary
| |
Collapse
|
248
|
A population of Nestin-expressing progenitors in the cerebellum exhibits increased tumorigenicity. Nat Neurosci 2013; 16:1737-44. [PMID: 24141309 PMCID: PMC3845444 DOI: 10.1038/nn.3553] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 09/13/2013] [Indexed: 12/12/2022]
Abstract
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 mouse 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.
Collapse
|
249
|
Stem cells expanded from the human embryonic hindbrain stably retain regional specification and high neurogenic potency. J Neurosci 2013; 33:12407-22. [PMID: 23884946 DOI: 10.1523/jneurosci.0130-13.2013] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Stem cell lines that faithfully maintain the regional identity and developmental potency of progenitors in the human brain would create new opportunities in developmental neurobiology and provide a resource for generating specialized human neurons. However, to date, neural progenitor cultures derived from the human brain have either been short-lived or exhibit restricted, predominantly glial, differentiation capacity. Pluripotent stem cells are an alternative source, but to ascertain definitively the identity and fidelity of cell types generated solely in vitro is problematic. Here, we show that hindbrain neuroepithelial stem (hbNES) cells can be derived and massively expanded from early human embryos (week 5-7, Carnegie stage 15-17). These cell lines are propagated in adherent culture in the presence of EGF and FGF2 and retain progenitor characteristics, including SOX1 expression, formation of rosette-like structures, and high neurogenic capacity. They generate GABAergic, glutamatergic and, at lower frequency, serotonergic neurons. Importantly, hbNES cells stably maintain hindbrain specification and generate upper rhombic lip derivatives on exposure to bone morphogenetic protein (BMP). When grafted into neonatal rat brain, they show potential for integration into cerebellar development and produce cerebellar granule-like cells, albeit at low frequency. hbNES cells offer a new system to study human cerebellar specification and development and to model diseases of the hindbrain. They also provide a benchmark for the production of similar long-term neuroepithelial-like stem cells (lt-NES) from pluripotent cell lines. To our knowledge, hbNES cells are the first demonstration of highly expandable neuroepithelial stem cells derived from the human embryo without genetic immortalization.
Collapse
|
250
|
Srivastava R, Kumar M, Peineau S, Csaba Z, Mani S, Gressens P, El Ghouzzi V. Conditional induction of Math1 specifies embryonic stem cells to cerebellar granule neuron lineage and promotes differentiation into mature granule neurons. Stem Cells 2013; 31:652-65. [PMID: 23225629 DOI: 10.1002/stem.1295] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 10/23/2012] [Indexed: 12/16/2022]
Abstract
Directing differentiation of embryonic stem cells (ESCs) to specific neuronal subtype is critical for modeling disease pathology in vitro. An attractive means of action would be to combine regulatory differentiation factors and extrinsic inductive signals added to the culture medium. In this study, we have generated mature cerebellar granule neurons by combining a temporally controlled transient expression of Math1, a master gene in granule neuron differentiation, with inductive extrinsic factors involved in cerebellar development. Using a Tetracyclin-On transactivation system, we overexpressed Math1 at various stages of ESCs differentiation and found that the yield of progenitors was considerably increased when Math1 was induced during embryonic body stage. Math1 triggered expression of Mbh1 and Mbh2, two target genes directly involved in granule neuron precursor formation and strong expression of early cerebellar territory markers En1 and NeuroD1. Three weeks after induction, we observed a decrease in the number of glial cells and an increase in that of neurons albeit still immature. Combining Math1 induction with extrinsic factors specifically increased the number of neurons that expressed Pde1c, Zic1, and GABAα6R characteristic of mature granule neurons, formed "T-shaped" axons typical of granule neurons, and generated synaptic contacts and action potentials in vitro. Finally, in vivo implantation of Math1-induced progenitors into young adult mice resulted in cell migration and settling of newly generated neurons in the cerebellum. These results show that conditional induction of Math1 drives ESCs toward the cerebellar fate and indicate that acting on both intrinsic and extrinsic factors is a powerful means to modulate ESCs differentiation and maturation into a specific neuronal lineage.
Collapse
|