1
|
Liu D, Wang J, Tian E, Chen J, Kong W, Lu Y, Zhang S. mGluR1/IP3/ERK signaling pathway regulates vestibular compensation in ON UBCs of the cerebellar flocculus. CNS Neurosci Ther 2024; 30:e14419. [PMID: 37622292 PMCID: PMC10848063 DOI: 10.1111/cns.14419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 07/16/2023] [Accepted: 08/09/2023] [Indexed: 08/26/2023] Open
Abstract
AIMS To investigate the role of mGluR1α in cerebellar unipolar brush cells (UBC) in mediating vestibular compensation (VC), using mGluR1α agonist and antagonist to modulate ON UBC neurons, and explore the mGluR1/IP3/extracellular signal-regulated kinase (ERK) signaling pathway. METHODS First, AAV virus that knockdown ON UBC (mGluR1α) were injected into cerebellar UBC by stereotactic, and verified by immunofluorescence and western blot. The effect on VC was evaluated after unilateral labyrinthectomy (UL). Second, saline, (RS)-3,5-dihydroxyphenylglycine (DHPG), and LY367385 were injected into tubes implanted in rats at different time points after UL separately. The effect on ON UBC neuron activity was evaluated by immunofluorescence. Then, Phosphoinositide (PI) and p-ERK1/2 levels of mGluR1α were analyzed by ELISA after UL. The protein levels of p-ERK and total ERK were verified by western blot. In addition, the effect of mGluR1α activation or inhibition on VC-related behavior was observed. RESULTS mGluR1α knockdown induced VC phenotypes. DHPG increased ON UBC activity, while LY367385 reduced ON UBC activity. DHPG group showed an increase in PI and p-ERK1/2 levels, while LY367385 group showed a decrease in PI and p-ERK1/2 levels in cerebellar UBC of rats. The western blot results of p-ERK and total ERK confirm and support the observations. DHPG alleviated VC-related behavior phenotypes, while LY367385 exacerbated vestibular decompensation-like behavior induced by UL. CONCLUSION mGluR1α activity in cerebellar ON UBC is crucial for mediating VC through the mGluR1/IP3/ERK signaling pathway, which affects ON UBC neuron activity and contributes to the pathogenesis of VC.
Collapse
Affiliation(s)
- Dan Liu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
- Institute of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Jun Wang
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
- Institute of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - E. Tian
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
- Institute of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Jingyu Chen
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
- Institute of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Weijia Kong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
- Institute of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Yisheng Lu
- Department of Physiology, School of Basic MedicineHuazhong University of Science and TechnologyWuhanChina
- Institute of Brain Research, Collaborative Innovation Center for Brain ScienceHuazhong University of Science and TechnologyWuhanChina
| | - Sulin Zhang
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
- Institute of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| |
Collapse
|
2
|
Hamad MIK, Emerald BS, Kumar KK, Ibrahim MF, Ali BR, Bataineh MF. Extracellular molecular signals shaping dendrite architecture during brain development. Front Cell Dev Biol 2023; 11:1254589. [PMID: 38155836 PMCID: PMC10754048 DOI: 10.3389/fcell.2023.1254589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 11/28/2023] [Indexed: 12/30/2023] Open
Abstract
Proper growth and branching of dendrites are crucial for adequate central nervous system (CNS) functioning. The neuronal dendritic geometry determines the mode and quality of information processing. Any defects in dendrite development will disrupt neuronal circuit formation, affecting brain function. Besides cell-intrinsic programmes, extrinsic factors regulate various aspects of dendritic development. Among these extrinsic factors are extracellular molecular signals which can shape the dendrite architecture during early development. This review will focus on extrinsic factors regulating dendritic growth during early neuronal development, including neurotransmitters, neurotrophins, extracellular matrix proteins, contact-mediated ligands, and secreted and diffusible cues. How these extracellular molecular signals contribute to dendritic growth has been investigated in developing nervous systems using different species, different areas within the CNS, and different neuronal types. The response of the dendritic tree to these extracellular molecular signals can result in growth-promoting or growth-limiting effects, and it depends on the receptor subtype, receptor quantity, receptor efficiency, the animal model used, the developmental time windows, and finally, the targeted signal cascade. This article reviews our current understanding of the role of various extracellular signals in the establishment of the architecture of the dendrites.
Collapse
Affiliation(s)
- Mohammad I. K. Hamad
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Kukkala K. Kumar
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Marwa F. Ibrahim
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Bassam R. Ali
- Department of Genetics and Genomics, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Mo’ath F. Bataineh
- Department of Nutrition and Health, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| |
Collapse
|
3
|
Ranjbar H, Soti M, Razavinasab M, Kohlmeier KA, Shabani M. The neglected role of endocannabinoid actions at TRPC channels in ataxia. Neurosci Biobehav Rev 2022; 141:104860. [PMID: 36087758 DOI: 10.1016/j.neubiorev.2022.104860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 08/24/2022] [Accepted: 09/03/2022] [Indexed: 12/01/2022]
Abstract
Transient receptor potential (TRP) channels are highly expressed in cells of the cerebellum including in the dendrites and somas of Purkinje cells (PCs). Their endogenous activation promotes influx of Ca2+ and Na+, resulting in depolarization. TRP channels can be activated by endogenous endocannabinoids (eCBs) and activity of TRP channels has been shown to modulate GABA and glutamate transmission. Ataxia is caused by disruption of multiple intracellular pathways which often involve changes in Ca2+ homeostasis that can result in neural cellular dysfunction and cell death. Based on available literature, alteration of transmission of eCBs would be expected to change activity of cerebellar TRP channels. Antagonists of the endocannabinoid system (ECS) including enzymes which break eCBs down have been shown to result in reductions in postsynaptic excitatory activity mediated by TRPC channels. Further, TRPC channel antagonists could modulate both pre and postsynaptically-mediated glutamatergic and GABAergic transmission, resulting in reductions in cell death due to excitotoxicity and dysfunctions caused by abnormal inhibitory signaling. Accordingly, TRP channels, and in particular the TRPC channel, represent a potential therapeutic target for management of ataxia.
Collapse
Affiliation(s)
- Hoda Ranjbar
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Monavareh Soti
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Moazamehosadat Razavinasab
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Kristi A Kohlmeier
- Department of Drug Design and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mohammad Shabani
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran.
| |
Collapse
|
4
|
Wu QW, Kapfhammer JP. The Emerging Key Role of the mGluR1-PKCγ Signaling Pathway in the Pathogenesis of Spinocerebellar Ataxias: A Neurodevelopmental Viewpoint. Int J Mol Sci 2022; 23:ijms23169169. [PMID: 36012439 PMCID: PMC9409119 DOI: 10.3390/ijms23169169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 12/19/2022] Open
Abstract
Spinocerebellar ataxias (SCAs) are a heterogeneous group of autosomal dominantly inherited progressive disorders with degeneration and dysfunction of the cerebellum. Although different subtypes of SCAs are classified according to the disease-associated causative genes, the clinical syndrome of the ataxia is shared, pointing towards a possible convergent pathogenic pathway among SCAs. In this review, we summarize the role of SCA-associated gene function during cerebellar Purkinje cell development and discuss the relationship between SCA pathogenesis and neurodevelopment. We will summarize recent studies on molecules involved in SCA pathogenesis and will focus on the mGluR1-PKCγ signaling pathway evaluating the possibility that this might be a common pathway which contributes to these diseases.
Collapse
|
5
|
Hamad MIK, Petrova P, Daoud S, Rabaya O, Jbara A, Melliti N, Leifeld J, Jakovčevski I, Reiss G, Herz J, Förster E. Reelin restricts dendritic growth of interneurons in the neocortex. Development 2021; 148:272055. [PMID: 34414407 DOI: 10.1242/dev.199718] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/12/2021] [Indexed: 11/20/2022]
Abstract
Reelin is a large secreted glycoprotein that regulates neuronal migration, lamination and establishment of dendritic architecture in the embryonic brain. Reelin expression switches postnatally from Cajal-Retzius cells to interneurons. However, reelin function in interneuron development is still poorly understood. Here, we have investigated the role of reelin in interneuron development in the postnatal neocortex. To preclude early cortical migration defects caused by reelin deficiency, we employed a conditional reelin knockout (RelncKO) mouse to induce postnatal reelin deficiency. Induced reelin deficiency caused dendritic hypertrophy in distal dendritic segments of neuropeptide Y-positive (NPY+) and calretinin-positive (Calr+) interneurons, and in proximal dendritic segments of parvalbumin-positive (Parv+) interneurons. Chronic recombinant Reelin treatment rescued dendritic hypertrophy in Relncko interneurons. Moreover, we provide evidence that RelncKO interneuron hypertrophy is due to presynaptic GABABR dysfunction. Thus, GABABRs in RelncKO interneurons were unable to block N-type (Cav2.2) Ca2+ channels that control neurotransmitter release. Consequently, the excessive Ca2+ influx through AMPA receptors, but not NMDA receptors, caused interneuron dendritic hypertrophy. These findings suggest that reelin acts as a 'stop-growth-signal' for postnatal interneuron maturation.
Collapse
Affiliation(s)
- Mohammad I K Hamad
- Institute for Anatomy and Clinical Morphology, School of Medicine, Faculty of Health, Witten/Herdecke University, Witten 58455, Germany.,Department of Neuroanatomy and Molecular Brain Research, Medical Faculty, Ruhr University Bochum, Bochum 44801, Germany
| | - Petya Petrova
- Department of Neuroanatomy and Molecular Brain Research, Medical Faculty, Ruhr University Bochum, Bochum 44801, Germany
| | - Solieman Daoud
- Department of Neuroanatomy and Molecular Brain Research, Medical Faculty, Ruhr University Bochum, Bochum 44801, Germany
| | - Obada Rabaya
- Department of Neuroanatomy and Molecular Brain Research, Medical Faculty, Ruhr University Bochum, Bochum 44801, Germany
| | - Abdalrahim Jbara
- Department of Neuroanatomy and Molecular Brain Research, Medical Faculty, Ruhr University Bochum, Bochum 44801, Germany
| | - Nesrine Melliti
- Department of Neuroanatomy and Molecular Brain Research, Medical Faculty, Ruhr University Bochum, Bochum 44801, Germany
| | - Jennifer Leifeld
- Department of Neuroanatomy and Molecular Brain Research, Medical Faculty, Ruhr University Bochum, Bochum 44801, Germany
| | - Igor Jakovčevski
- Institute for Anatomy and Clinical Morphology, School of Medicine, Faculty of Health, Witten/Herdecke University, Witten 58455, Germany
| | - Gebhard Reiss
- Institute for Anatomy and Clinical Morphology, School of Medicine, Faculty of Health, Witten/Herdecke University, Witten 58455, Germany
| | - Joachim Herz
- Departments of Molecular Genetics, Neuroscience, Neurology and Neurotherapeutics; Center for Translational Neurodegeneration Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Eckart Förster
- Department of Neuroanatomy and Molecular Brain Research, Medical Faculty, Ruhr University Bochum, Bochum 44801, Germany
| |
Collapse
|
6
|
Tellios V, Maksoud MJE, Xiang YY, Lu WY. Nitric Oxide Critically Regulates Purkinje Neuron Dendritic Development Through a Metabotropic Glutamate Receptor Type 1-Mediated Mechanism. THE CEREBELLUM 2021; 19:510-526. [PMID: 32270464 DOI: 10.1007/s12311-020-01125-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Nitric oxide (NO), specifically derived from neuronal nitric oxide synthase (nNOS), is a well-established regulator of synaptic transmission in Purkinje neurons (PNs), governing fundamental processes such as motor learning and coordination. Previous phenotypic analyses showed similar cerebellar structures between neuronal nitric oxide null (nNOS-/-) and wild-type (WT) adult male mice, despite prominent ataxic behavior within nNOS-/- mice. However, a study has yet to characterize PN molecular structure and their excitatory inputs during development in nNOS-/- mice. This study is the first to explore morphological abnormalities within the cerebellum of nNOS-/- mice, using immunohistochemistry and immunoblotting. This study sought to examine PN dendritic morphology and the expression of metabotropic glutamate receptor type 1 (mGluR1), vesicular glutamate transporter type 1 and 2 (vGluT1 and vGluT2), stromal interaction molecule 1 (STIM1), and calpain-1 within PNs of WT and nNOS-/- mice at postnatal day 7 (PD7), 2 weeks (2W), and 7 weeks (7W) of age. Results showed a decrease in PN dendritic branching at PD7 in nNOS-/- cerebella, while aberrant dendritic spine formation was noted in adult ages. Total protein expression of mGluR1 was decreased in nNOS-/- cerebella across development, while vGluT2, STIM1, and calpain-1 were significantly increased. Ex vivo treatment of WT slices with NOS inhibitor L-NAME increased calpain-1 expression, whereas treating nNOS-/- cerebellar slices with NO donor NOC-18 decreased calpain-1. Moreover, mGluR1 agonist DHPG increased calpain-1 in WT, but not in nNOS-/- slices. Together, these results indicate a novel role for nNOS/NO signaling in PN development, particularly by regulating an mGluR1-initiated calcium signaling mechanism.
Collapse
Affiliation(s)
- Vasiliki Tellios
- Graduate Program of Neuroscience, The University of Western Ontario, London, N6A 5B7, Canada.,Robarts Research Institute, London, N6A 5B7, Canada
| | - Matthew J E Maksoud
- Graduate Program of Neuroscience, The University of Western Ontario, London, N6A 5B7, Canada.,Robarts Research Institute, London, N6A 5B7, Canada
| | | | - Wei-Yang Lu
- Graduate Program of Neuroscience, The University of Western Ontario, London, N6A 5B7, Canada. .,Robarts Research Institute, London, N6A 5B7, Canada. .,Department of Physiology and Pharmacology, The University of Western Ontario, London, N6A 5B7, Canada.
| |
Collapse
|
7
|
Wu QW, Kapfhammer JP. Modulation of Increased mGluR1 Signaling by RGS8 Protects Purkinje Cells From Dendritic Reduction and Could Be a Common Mechanism in Diverse Forms of Spinocerebellar Ataxia. Front Cell Dev Biol 2021; 8:569889. [PMID: 33553137 PMCID: PMC7858651 DOI: 10.3389/fcell.2020.569889] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 12/30/2020] [Indexed: 12/13/2022] Open
Abstract
Spinocerebellar ataxias (SCAs) are a group of hereditary neurodegenerative diseases which are caused by diverse genetic mutations in a variety of different genes. We have identified RGS8, a regulator of G-protein signaling, as one of the genes which are dysregulated in different mouse models of SCA (e.g., SCA1, SCA2, SCA7, and SCA14). In the moment, little is known about the role of RGS8 for pathogenesis of spinocerebellar ataxia. We have studied the expression of RGS8 in the cerebellum in more detail and show that it is specifically expressed in mouse cerebellar Purkinje cells. In a mouse model of SCA14 with increased PKCγ activity, RGS8 expression was also increased. RGS8 overexpression could partially counteract the negative effects of DHPG-induced mGluR1 signaling for the expansion of Purkinje cell dendrites. Our results suggest that the increased expression of RGS8 is an important mediator of mGluR1 pathway dysregulation in Purkinje cells. These findings provide new insights in the role of RGS8 and mGluR1 signaling in Purkinje cells and for the pathology of SCAs.
Collapse
Affiliation(s)
- Qin-Wei Wu
- Institute of Anatomy, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Josef P Kapfhammer
- Institute of Anatomy, Department of Biomedicine, University of Basel, Basel, Switzerland
| |
Collapse
|
8
|
Dendritic Self-Avoidance and Morphological Development of Cerebellar Purkinje Cells. THE CEREBELLUM 2018; 17:701-708. [DOI: 10.1007/s12311-018-0984-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
9
|
Shimobayashi E, Kapfhammer JP. Calcium Signaling, PKC Gamma, IP3R1 and CAR8 Link Spinocerebellar Ataxias and Purkinje Cell Dendritic Development. Curr Neuropharmacol 2018; 16:151-159. [PMID: 28554312 PMCID: PMC5883377 DOI: 10.2174/1570159x15666170529104000] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 05/16/2017] [Accepted: 05/25/2017] [Indexed: 01/05/2023] Open
Abstract
Background Spinocerebellar ataxias (SCAs) are a group of cerebellar diseases characterized by progressive ataxia and cerebellar atrophy. Several forms of SCAs are caused by missense mutations or deletions in genes related to calcium signaling in Purkinje cells. Among them, spinocerebellar ataxia type 14 (SCA14) is caused by missense mutations in PRKCG gene which encodes protein kinase C gamma (PKCγ). It is remarkable that in several cases in which SCA is caused by point mutations in an individual gene, the affected genes are involved in the PKCγ signaling pathway and calcium signaling which is not only crucial for proper Purkinje cell function but is also involved in the control of Purkinje cell dendritic development. In this review, we will focus on the PKCγ signaling related genes and calcium signaling related genes then discuss their role for both Purkinje cell dendritic development and cerebellar ataxia. Methods Research related to SCAs and Purkinje cell dendritic development is reviewed. Results PKCγ dysregulation causes abnormal Purkinje cell dendritic development and SCA14. Carbonic anhydrase related protein 8 (Car8) encoding CAR8 and Itpr1 encoding IP3R1were identified as upregulated genes in one of SCA14 mouse model. IP3R1, CAR8 and PKCγ proteins are strongly and specifically expressed in Purkinje cells. The common function among them is that they are involved in the regulation of calcium homeostasis in Purkinje cells and their dysfunction causes ataxia in mouse and human. Furthermore, disruption of intracellular calcium homeostasis caused by mutations in some calcium channels in Purkinje cells links to abnormal Purkinje cell dendritic development and the pathogenesis of several SCAs. Conclusion Once PKCγ signaling related genes and calcium signaling related genes are disturbed, the normal dendritic development of Purkinje cells is impaired as well as the integration of signals from other neurons, resulting in abnormal development, cerebellar dysfunction and eventually Purkinje cell loss.
Collapse
Affiliation(s)
- Etsuko Shimobayashi
- Anatomical Institute, Department of Biomedicine Basel, University of Basel, Pestalozzistrasse 20, CH-4056 Basel, Switzerland
| | - Josef P Kapfhammer
- Anatomical Institute, Department of Biomedicine Basel, University of Basel, Pestalozzistrasse 20, CH-4056 Basel, Switzerland
| |
Collapse
|
10
|
Cerebellar Pathways in Mouse Model of Purkinje Cell Degeneration Detected by High-Angular Resolution Diffusion Imaging Tractography. THE CEREBELLUM 2018; 16:648-655. [PMID: 28102462 DOI: 10.1007/s12311-016-0842-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Cerebellar MR imaging has several challenging aspects, due to the fine, repetitive layered structure of cortical folia with underlying axonal pathways. In this MR study, we imaged with high-angular resolution diffusion imaging (HARDI) abnormal cerebellar cortical structure (gray matter) and myelinated axonal pathways (white matter) of a mouse spontaneous mutation, Purkinje cell degeneration (pcd), in which almost all Purkinje neurons degenerate, mainly between postnatal days 20 and 35. Mouse brains at postnatal day 20 (P20) and at 8 months were scanned, and known or expected abnormalities, such as reduction of the white matter volume, disorganized pathways likely linked to parallel fibers, mossy fibers, and other fibers running from/to the cerebellar cortex were observed in mutant mice. Such abnormalities were detected at both an early and a fully advanced degeneration stage. These results suggest that our diffusion MR tractography is useful for early detection and tracking of neuropathology in the cerebellum.
Collapse
|
11
|
Sherkhane P, Kapfhammer JP. Chronic pharmacological blockade of the Na + /Ca 2+ exchanger modulates the growth and development of the Purkinje cell dendritic arbor in mouse cerebellar slice cultures. Eur J Neurosci 2017; 46:2108-2120. [PMID: 28715135 DOI: 10.1111/ejn.13649] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 07/11/2017] [Accepted: 07/11/2017] [Indexed: 01/22/2023]
Abstract
The Na+ /Ca2+ exchanger (NCX) is a bidirectional plasma membrane antiporter involved in Ca2+ homeostasis in eukaryotes. NCX has three isoforms, NCX1-3, and all of them are expressed in the cerebellum. Immunostaining on cerebellar slice cultures indicates that NCX is widely expressed in the cerebellum, including expression in Purkinje cells. The pharmacological blockade of the forward mode of NCX (Ca2+ efflux mode) by bepridil moderately inhibited growth and development of Purkinje cell dendritic arbor in cerebellar slice cultures. However, the blockade of the reverse mode (Ca2+ influx mode) by KB-R7943 severely reduced the dendritic arbor and induced a morphological change with thickened distal dendrites. The effect of KB-R7943 on dendritic growth was unrelated to the activity of voltage-gated calcium channels and was also apparent in the absence of bioelectrical activity indicating that it was mediated by NCX expressed in Purkinje cells. We have used additional NCX inhibitors including CB-DMB, ORM-10103, SEA0400, YM-244769, and SN-6 which have higher specificity for NCX isoforms and target either the forward, reverse, or both modes. These inhibitors caused a strong dendritic reduction similar to that seen with KB-R7943, but did not elicit thickening of distal dendrites. Our findings indicate that disturbance of the NCX-dependent calcium transport in Purkinje cells induces a reduction of dendritic arbor, which is presumably caused by changes in the calcium handling, and underline the importance of the calcium equilibrium for the dendritic development in cerebellar Purkinje cells.
Collapse
Affiliation(s)
- Pradeep Sherkhane
- Department of Biomedicine, Anatomical Institute, University of Basel, Pestalozzistrasse 20, CH-4056, Basel, Switzerland
| | - Josef P Kapfhammer
- Department of Biomedicine, Anatomical Institute, University of Basel, Pestalozzistrasse 20, CH-4056, Basel, Switzerland
| |
Collapse
|
12
|
Becker EBE. The Moonwalker mouse: new insights into TRPC3 function, cerebellar development, and ataxia. THE CEREBELLUM 2015; 13:628-36. [PMID: 24797279 PMCID: PMC4155175 DOI: 10.1007/s12311-014-0564-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The Moonwalker (Mwk) mouse is a recent model of dominantly inherited cerebellar ataxia. The motor phenotype of the Mwk mouse is due to a gain-of-function mutation in the gene encoding the cation-permeable transient receptor potential channel (TRPC3). This mutation converts a threonine into an alanine in the highly conserved cytoplasmic S4–S5 linker of the channel, affecting channel gating. TRPC3 is highly expressed in cerebellar Purkinje cells and type II unipolar brush cells that both degenerate in the Mwk mouse. Studies of the Mwk mouse have provided new insights into the role of TRPC3 in cerebellar development and disease, which could not have been predicted from the Trpc3 knockout phenotype. Here, the genetic, behavioral, histological, and functional characterization of the Mwk mouse is reviewed. Moreover, the relationship of the Mwk mutant to other cerebellar mouse models and its relevance as a model for cerebellar ataxia are discussed.
Collapse
Affiliation(s)
- Esther B E Becker
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, OX1 3PT, UK,
| |
Collapse
|
13
|
Dulneva A, Lee S, Oliver PL, Di Gleria K, Kessler BM, Davies KE, Becker EBE. The mutant Moonwalker TRPC3 channel links calcium signaling to lipid metabolism in the developing cerebellum. Hum Mol Genet 2015; 24:4114-25. [PMID: 25908616 PMCID: PMC4476454 DOI: 10.1093/hmg/ddv150] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 04/20/2015] [Indexed: 12/22/2022] Open
Abstract
The Moonwalker (Mwk) mouse is a model of dominantly inherited cerebellar ataxia caused by a gain-of-function mutation in the transient receptor potential (TRP) channel TRPC3. Here, we report impairments in dendritic growth and synapse formation early on during Purkinje cell development in the Mwk cerebellum that are accompanied by alterations in calcium signaling. To elucidate the molecular effector pathways that regulate Purkinje cell dendritic arborization downstream of mutant TRPC3, we employed transcriptomic analysis of developing Purkinje cells isolated by laser-capture microdissection. We identified significant gene and protein expression changes in molecules involved in lipid metabolism. Consistently, lipid homeostasis in the Mwk cerebellum was found to be disturbed, and treatment of organotypic cerebellar slices with ceramide significantly improved dendritic outgrowth of Mwk Purkinje cells. These findings provide the first mechanistic insights into the TRPC3-dependent mechanisms, by which activated calcium signaling is coupled to lipid metabolism and the regulation of Purkinje cell development in the Mwk cerebellum.
Collapse
Affiliation(s)
- Anna Dulneva
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK and
| | - Sheena Lee
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK and
| | - Peter L Oliver
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK and
| | - Katalin Di Gleria
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Benedikt M Kessler
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Kay E Davies
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK and
| | - Esther B E Becker
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK and
| |
Collapse
|
14
|
Zeng C, Tian F, Xiao B. TRPC Channels: Prominent Candidates of Underlying Mechanism in Neuropsychiatric Diseases. Mol Neurobiol 2014; 53:631-647. [DOI: 10.1007/s12035-014-9004-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 11/13/2014] [Indexed: 10/24/2022]
|
15
|
The plasma membrane Ca2+-ATPase2 (PMCA2) is involved in the regulation of Purkinje cell dendritic growth in cerebellar organotypic slice cultures. Neural Plast 2013; 2013:321685. [PMID: 24288624 PMCID: PMC3830849 DOI: 10.1155/2013/321685] [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: 07/04/2013] [Revised: 08/30/2013] [Accepted: 09/03/2013] [Indexed: 11/17/2022] Open
Abstract
Purkinje cells are the principal neurons of the cerebellar cortex and have an extensive and elaborate dendritic tree. Chronic activation of type I metabotropic glutamate receptors inhibits Purkinje cell dendritic growth in organotypic cerebellar slice cultures. This effect is mediated by calcium influx through P/Q-type and T-type Ca2+ channels. We have now studied the role of the plasma membrane Ca2+-ATPase2 (PMCA2), a major calcium extrusion pump, for Purkinje cell dendritic development. We found that PMCA2 is strongly expressed in the plasma membrane and dendritic spines of Purkinje cells in organotypic slice cultures compatible with a role for controlling the local dendritic calcium equilibrium. Inhibition of PMCA2 activity by carboxyeosin resulted in a moderate reduction of Purkinje cell dendritic tree size indicating that the extrusion of calcium by PMCA2 is important for maintaining the dendritic calcium concentration and controlling dendritic growth. When inhibition of PMCA2 was combined with stimulation of type I metabotropic glutamate receptors, it partially rescued dendritic morphology. This protection can be explained by a compensatory inactivation of voltage-gated calcium channels in Purkinje cells after PMCA2 inhibition. Our results demonstrate that PMCA2 activity is an important regulator of the dendritic calcium equilibrium controlling Purkinje cell dendritic growth.
Collapse
|
16
|
Human synaptic plasticity gene expression profile and dendritic spine density changes in HIV-infected human CNS cells: role in HIV-associated neurocognitive disorders (HAND). PLoS One 2013; 8:e61399. [PMID: 23620748 PMCID: PMC3631205 DOI: 10.1371/journal.pone.0061399] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 03/08/2013] [Indexed: 11/19/2022] Open
Abstract
HIV-associated neurocognitive disorders (HAND) is characterized by development of cognitive, behavioral and motor abnormalities, and occur in approximately 50% of HIV infected individuals. Our current understanding of HAND emanates mainly from HIV-1 subtype B (clade B), which is prevalent in USA and Western countries. However very little information is available on neuropathogenesis of HIV-1 subtype C (clade C) that exists in Sub-Saharan Africa and Asia. Therefore, studies to identify specific neuropathogenic mechanisms associated with HAND are worth pursuing to dissect the mechanisms underlying this modulation and to prevent HAND particularly in clade B infection. In this study, we have investigated 84 key human synaptic plasticity genes differential expression profile in clade B and clade C infected primary human astrocytes by using RT(2) Profile PCR Array human Synaptic Plasticity kit. Among these, 31 and 21 synaptic genes were significantly (≥3 fold) down-regulated and 5 genes were significantly (≥3 fold) up-regulated in clade B and clade C infected cells, respectively compared to the uninfected control astrocytes. In flow-cytometry analysis, down-regulation of postsynaptic density and dendrite spine morphology regulatory proteins (ARC, NMDAR1 and GRM1) was confirmed in both clade B and C infected primary human astrocytes and SK-N-MC neuroblastoma cells. Further, spine density and dendrite morphology changes by confocal microscopic analysis indicates significantly decreased spine density, loss of spines and decreased dendrite diameter, total dendrite and spine area in clade B infected SK-N-MC neuroblastoma cells compared to uninfected and clade C infected cells. We have also observed that, in clade B infected astrocytes, induction of apoptosis was significantly higher than in the clade C infected astrocytes. In conclusion, this study suggests that down-regulation of synaptic plasticity genes, decreased dendritic spine density and induction of apoptosis in astrocytes may contribute to the severe neuropathogenesis in clade B infection.
Collapse
|
17
|
Conserved cellular distribution of the glutamate receptors GluA2/3, mGlu1a and mGlu2/3 in isolated cultures of rat cerebellum. J Chem Neuroanat 2012; 45:26-35. [DOI: 10.1016/j.jchemneu.2012.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 06/15/2012] [Accepted: 07/01/2012] [Indexed: 01/23/2023]
|
18
|
Kapfhammer JP, Gugger OS. The analysis of purkinje cell dendritic morphology in organotypic slice cultures. J Vis Exp 2012:3637. [PMID: 22473312 DOI: 10.3791/3637] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Purkinje cells are an attractive model system for studying dendritic development, because they have an impressive dendritic tree which is strictly oriented in the sagittal plane and develops mostly in the postnatal period in small rodents (3). Furthermore, several antibodies are available which selectively and intensively label Purkinje cells including all processes, with anti-Calbindin D28K being the most widely used. For viewing of dendrites in living cells, mice expressing EGFP selectively in Purkinje cells (11) are available through Jackson labs. Organotypic cerebellar slice cultures cells allow easy experimental manipulation of Purkinje cell dendritic development because most of the dendritic expansion of the Purkinje cell dendritic tree is actually taking place during the culture period (4). We present here a short, reliable and easy protocol for viewing and analyzing the dendritic morphology of Purkinje cells grown in organotypic cerebellar slice cultures. For many purposes, a quantitative evaluation of the Purkinje cell dendritic tree is desirable. We focus here on two parameters, dendritic tree size and branch point numbers, which can be rapidly and easily determined from anti-calbindin stained cerebellar slice cultures. These two parameters yield a reliable and sensitive measure of changes of the Purkinje cell dendritic tree. Using the example of treatments with the protein kinase C (PKC) activator PMA and the metabotropic glutamate receptor 1 (mGluR1) we demonstrate how differences in the dendritic development are visualized and quantitatively assessed. The combination of the presence of an extensive dendritic tree, selective and intense immunostaining methods, organotypic slice cultures which cover the period of dendritic growth and a mouse model with Purkinje cell specific EGFP expression make Purkinje cells a powerful model system for revealing the mechanisms of dendritic development.
Collapse
|
19
|
Gugger OS, Hartmann J, Birnbaumer L, Kapfhammer JP. P/Q-type and T-type calcium channels, but not type 3 transient receptor potential cation channels, are involved in inhibition of dendritic growth after chronic metabotropic glutamate receptor type 1 and protein kinase C activation in cerebellar Purkinje cells. Eur J Neurosci 2011; 35:20-33. [PMID: 22188405 DOI: 10.1111/j.1460-9568.2011.07942.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The development of a neuronal dendritic tree is modulated both by signals from afferent fibers and by an intrinsic program. We have previously shown that chronic activation of either type 1 metabotropic glutamate receptors (mGluR1s) or protein kinase C (PKC) in organotypic cerebellar slice cultures of mice and rats severely inhibits the growth and development of the Purkinje cell dendritic tree. The signaling events linking receptor activation to the regulation of dendritic growth remain largely unknown. We have studied whether channels allowing the entry of Ca(2+) into Purkinje cells, in particular the type 3 transient receptor potential cation channels (TRPC3s), P/Q-type Ca(2+) channels, and T-type Ca(2+) channels, might be involved in signaling after mGluR1 or PKC stimulation. We show that the inhibition of dendritic growth seen after mGluR1 or PKC stimulation is partially rescued by pharmacological blockade of P/Q-type and T-type Ca(2+) channels, indicating that activation of these channels mediating Ca(2+) influx contributes to the inhibition of dendritic growth. In contrast, the absence of Ca(2+) -permeable TRPC3s in TRPC3-deficient mice or pharmacological blockade had no effect on mGluR1-mediated and PKC-mediated inhibition of Purkinje cell dendritic growth. Similarly, blockade of Ca(2+) influx through glutamate receptor δ2 or R-type Ca(2+) channels or inhibition of release from intracellular stores did not influence mGluR1-mediated and PKC-mediated inhibition of Purkinje cell dendritic growth. These findings suggest that both T-type and P/Q-type Ca(2+) channels, but not TRPC3 or other Ca(2+) -permeable channels, are involved in mGluR1 and PKC signaling leading to the inhibition of dendritic growth in cerebellar Purkinje cells.
Collapse
Affiliation(s)
- Olivia S Gugger
- Department of Biomedicine Basel, Anatomical Institute, University of Basel, Pestalozzistr. 20, CH 4056 Basel, Switzerland
| | | | | | | |
Collapse
|
20
|
Albuminuria and glomerular damage in mice lacking the metabotropic glutamate receptor 1. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:1257-69. [PMID: 21356376 DOI: 10.1016/j.ajpath.2010.11.050] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 09/27/2010] [Accepted: 11/01/2010] [Indexed: 02/02/2023]
Abstract
The metabotropic glutamate (mGlu) receptor 1 (GRM1) has been shown to play an important role in neuronal cells by triggering, through calcium release from intracellular stores, various signaling pathways that finally modulate neuron excitability, synaptic plasticity, and mechanisms of feedback regulation of neurotransmitter release. Herein, we show that Grm1 is expressed in glomerular podocytes and that a glomerular phenotype is exhibited by Grm1(crv4) mice carrying a spontaneous recessive inactivating mutation of the gene. Homozygous Grm1(crv4/crv4) and, to a lesser extent, heterozygous mice show albuminuria, podocyte foot process effacement, and reduced levels of nephrin and other proteins known to contribute to the maintenance of podocyte cell structure. Overall, the present data extend the role of mGlu1 receptor to the glomerular filtration barrier. The regulatory action of mGlu1 receptor in dendritic spine morphology and in the control of glutamate release is well acknowledged in neuronal cells. Analogously, we speculate that mGlu1 receptor may regulate foot process morphology and intercellular signaling in the podocyte.
Collapse
|
21
|
Li J, Gu X, Ma Y, Calicchio ML, Kong D, Teng YD, Yu L, Crain AM, Vartanian TK, Pasqualini R, Arap W, Libermann TA, Snyder EY, Sidman RL. Nna1 mediates Purkinje cell dendritic development via lysyl oxidase propeptide and NF-κB signaling. Neuron 2010; 68:45-60. [PMID: 20920790 DOI: 10.1016/j.neuron.2010.08.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2010] [Indexed: 01/19/2023]
Abstract
The molecular pathways controlling cerebellar Purkinje cell dendrite formation and maturation are poorly understood. The Purkinje cell degeneration (pcd) mutant mouse is characterized by mutations in Nna1, a gene discovered in an axonal regenerative context, but whose actual function in development and disease is unknown. We found abnormal development of Purkinje cell dendrites in postnatal pcd(Sid) mice and linked this deficit to a deletion mutation in exon 7 of Nna1. With single cell gene profiling and virus-based gene transfer, we analyzed a molecular pathway downstream to Nna1 underlying abnormal Purkinje cell dendritogenesis in pcd(Sid) mice. We discovered that mutant Nna1 dramatically increases intranuclear localization of lysyl oxidase propeptide, which interferes with NF-κB RelA signaling and microtubule-associated protein regulation of microtubule stability, leading to underdevelopment of Purkinje cell dendrites. These findings provide insight into Nna1's role in neuronal development and why its absence renders Purkinje cells more vulnerable.
Collapse
Affiliation(s)
- Jianxue Li
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Foxp4 is essential in maintenance of Purkinje cell dendritic arborization in the mouse cerebellum. Neuroscience 2010; 172:562-71. [PMID: 20951773 DOI: 10.1016/j.neuroscience.2010.10.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 10/09/2010] [Accepted: 10/11/2010] [Indexed: 12/31/2022]
Abstract
Purkinje cells (PCs) are one of the principal neurons in the cerebellar cortex that play a central role in the coordination of fine-tuning body movement and balance. To acquire normal cerebellum function, PCs develop extensive dendritic arbors that establish synaptic connections with the parallel fibers of granule cells to form the proper neuronal circuitry. Therefore, dendritic arborization of PCs is an important developmental step to construct the mature neural network in the cerebellum. However, the genetic control of this process is not fully understood. In this study, Foxp4, a forkhead transcription factor that is expressed specifically in migrating and mature PCs of cerebellum from embryonic stages to adulthood, was knocked down by small interfering RNA (siRNA) in organotypic cerebellar slice culture. When Foxp4 expression was knocked down at postnatal day 5 (P5), no abnormalities for early dendritic remodeling of PCs were observed. However, when Foxp4 was knocked down in P10 cerebellar slices, the organization of PC dendritic arbors was highly impaired, leaving hypoplastic but non-apoptotic cell bodies. The radial alignment of Bergmann glial fibers that associated with PC dendrites was also lost. These results suggest that Foxp4 is dispensable for the early PC dendrite outgrowth, but is essential for the maintenance of PC dendritic arborization and subsequent association with Bergmann glial fibers.
Collapse
|
23
|
Kawaguchi K, Habara T, Terashima T, Kikkawa S. GABA modulates development of cerebellar Purkinje cell dendrites under control of endocannabinoid signaling. J Neurochem 2010; 114:627-38. [PMID: 20477908 DOI: 10.1111/j.1471-4159.2010.06793.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Purkinje cells (PCs) are the sole projection neurons in the cerebellar cortex with highly arborized dendrites, on which they receive glutamatergic and GABAergic inputs. Whereas influences of glutamatergic inputs on dendritic development of PCs have been well studied, those of GABA remain elusive. Here we examined effects of GABAergic signaling on dendritogenesis of PCs in dissociated cerebellar cultures. Treatment with GABA(A) agonists such as muscimol altered Purkinje dendrites to longer and less branched morphology, while GABA(A) antagonists resulted in shorter dendrites. In contrast, neither a GABA(B) agonist nor antagonist had major effects on dendritic morphology. Simultaneous addition of a glutamatergic antagonist cocktail or the Trk receptor antagonist K252a did not block muscimol. Furthermore, blockade of endocannabinoid signaling by either AM251 or tetrahydrolipstatin resulted in longer and less branched dendrites similar to those treated with GABA(A) agonists suggesting upstream regulation by endocannabinoids. Notably, whereas Purkinje dendrites extended in random directions in the presence of muscimol, they oriented to coexisting GABAergic interneurons when treated with AM251. Taken together, our results postulate the hypothesis that GABA released from the cerebellar interneurons modulates dendritogenesis of PCs in an endocannabinoid-dependent manner in the developing cerebellar cortex.
Collapse
Affiliation(s)
- Koji Kawaguchi
- Division of Developmental Neurobiology, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Chuo-ku, Kobe, Japan
| | | | | | | |
Collapse
|
24
|
Gugger OS, Kapfhammer JP. Reduced size of the dendritic tree does not protect Purkinje cells from excitotoxic death. J Neurosci Res 2010; 88:774-83. [PMID: 19798747 DOI: 10.1002/jnr.22247] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Purkinje cell loss by excitotoxic damage is a typical finding in many cerebellar diseases. One important aspect of this high sensitivity of Purkinje cells to excitotoxic death might be the enormous size of their dendritic tree, with a high load of excitatory glutamate receptors. We have studied whether reduction in the size of the dendritic tree might confer resistance against excitotoxic death to Purkinje cells. We have grown Purkinje cells in organotypic cerebellar slice cultures under chronic activation of metabotropic glutamate receptors or of protein kinase C. Both treatments strongly reduced dendritic tree size. After this treatment, cells were exposed to the glutamate receptor agonist AMPA, which has a strong excitotoxic effect on Purkinje cells. We found that Purkinje cells with small dendritic trees were as sensitive to AMPA exposure as untreated control cells with large dendritic trees. Immunostaining against vesicular glutamate transporter 1 revealed that the small dendritic trees were densely covered by glutamatergic terminals. Our results indicate that the expansion of the dendritic tree and the total number of AMPA receptors per neuron do not play a major role in determining the susceptibility of Purkinje cells to excitotoxic death.
Collapse
Affiliation(s)
- Olivia S Gugger
- Anatomical Institute, Department of Biomedicine, University of Basel, Basel, Switzerland
| | | |
Collapse
|
25
|
A point mutation in TRPC3 causes abnormal Purkinje cell development and cerebellar ataxia in moonwalker mice. Proc Natl Acad Sci U S A 2009; 106:6706-11. [PMID: 19351902 DOI: 10.1073/pnas.0810599106] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The hereditary ataxias are a complex group of neurological disorders characterized by the degeneration of the cerebellum and its associated connections. The molecular mechanisms that trigger the loss of Purkinje cells in this group of diseases remain incompletely understood. Here, we report a previously undescribed dominant mouse model of cerebellar ataxia, moonwalker (Mwk), that displays motor and coordination defects and loss of cerebellar Purkinje cells. Mwk mice harbor a gain-of-function mutation (T635A) in the Trpc3 gene encoding the nonselective transient receptor potential cation channel, type C3 (TRPC3), resulting in altered TRPC3 channel gating. TRPC3 is highly expressed in Purkinje cells during the phase of dendritogenesis. Interestingly, growth and differentiation of Purkinje cell dendritic arbors are profoundly impaired in Mwk mice. Our findings define a previously unknown role for TRPC3 in both dendritic development and survival of Purkinje cells, and provide a unique mechanism underlying cerebellar ataxia.
Collapse
|
26
|
Neuregulin signaling is dispensable for NMDA- and GABA(A)-receptor expression in the cerebellum in vivo. J Neurosci 2009; 29:2404-13. [PMID: 19244516 DOI: 10.1523/jneurosci.4303-08.2009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Neuregulin-1s (NRG-1s) are a family of growth and differentiation factors with multiple roles in the development and function in different organs including the nervous system. Among the proposed functions of NRG-1s in the nervous system is the regulation of genes encoding certain neurotransmitter receptors during synapse formation as well as of other aspects of synaptic function. Here, we have examined, in granule cells of the cerebellum in vivo, the role of NRGs in the induction of NMDA receptor (NMDA-R) and GABA(A) receptor (GABA(A)-R), which are thought to be induced by NRG-1 secreted by the synaptic inputs. To this end, we used the Cre/loxP system to genetically ablate the NRG receptors ErbB2 and ErbB4 selectively in these cells, thus eliminating all NRG-mediated signaling to them. Unlike previous reports using cultured granule cells to address the same question, we found that the developmental expression patterns of the mRNAs encoding the NR2C subunit of the NMDA-R and the beta2-subunit of the GABA(A)-R is normal in mice lacking the NRG receptors ErbB2 and ErbB4. Likewise, no alterations in cerebellar morphology nor in certain aspects of cerebellar wiring were resolved in these mutants. We conclude that NRG/ErbB signaling to the granule cells is dispensable for the normal development of their synaptic inputs.
Collapse
|
27
|
Hartmann J, Konnerth A. Mechanisms of metabotropic glutamate receptor-mediated synaptic signalling in cerebellar Purkinje cells. Acta Physiol (Oxf) 2009. [DOI: 10.1111/j.1748-1716.2008.01923.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
28
|
Abdurakhmonov IY, Devor EJ, Buriev ZT, Huang L, Makamov A, Shermatov SE, Bozorov T, Kushanov FN, Mavlonov GT, Abdukarimov A. Small RNA regulation of ovule development in the cotton plant, G. hirsutum L. BMC PLANT BIOLOGY 2008; 8:93. [PMID: 18793449 PMCID: PMC2564936 DOI: 10.1186/1471-2229-8-93] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Accepted: 09/16/2008] [Indexed: 02/08/2023]
Abstract
BACKGROUND The involvement of small RNAs in cotton fiber development is under explored. The objective of this work was to directly clone, annotate, and analyze small RNAs of developing ovules to reveal the candidate small interfering RNA/microRNAs involved in cotton ovule and fiber development. RESULTS We cloned small RNA sequences from 0-10 days post anthesis (DPA) developing cotton ovules. A total of 6691 individual colonies were sequenced from 11 ovule small RNA libraries that yielded 2482 candidate small RNAs with a total of 583 unique sequence signatures. The majority (362, 62.1%) of these 583 sequences were 24 nt long with an additional 145 sequences (24.9%) in the 21 nt to 23 nt size range. Among all small RNA sequence signatures only three mirBase-confirmed plant microRNAs (miR172, miR390 and ath-miR853-like) were identified and only two miRNA-containing clones were recovered beyond 4 DPA. Further, among all of the small RNA sequences obtained from the small RNA pools in developing ovules, only 15 groups of sequences were observed in more than one DPA period. Of these, only five were present in more than two DPA periods. Two of these were miR-172 and miR-390 and a third was identified as 5.8S rRNA sequence. Thus, the vast majority of sequence signatures were expressed in only one DPA period and this included nearly all of the 24 nt sequences. Finally, we observed a distinct DPA-specific expression pattern among our clones based upon sequence abundance. Sequences occurring only once were far more likely to be seen in the 0 to 2 DPA periods while those occurring five or more times were the majority in later periods. CONCLUSION This initial survey of small RNA sequences present in developing ovules in cotton indicates that fiber development is under complex small RNA regulation. Taken together, the results of this initial small RNA screen of developing cotton ovules is most consistent with a model, proposed by Baulcombe, that there are networks of small RNAs that are induced in a cascade fashion by the action of miRNAs and that the nature of these cascades can change from tissue to tissue and developmental stage to developmental stage.
Collapse
Affiliation(s)
- Ibrokhim Y Abdurakhmonov
- Center of Genomic Technologies, Institute of Genetics and Plant Experimental Biology, Academy of Sciences of Uzbekistan. Yuqori Yuz, Qibray region Tashkent district, 111226 Uzbekistan
| | - Eric J Devor
- Molecular Genetics, Integrated DNA Technologies, 1710 Commercial Park, Coralville, IA, 52241, USA
| | - Zabardast T Buriev
- Center of Genomic Technologies, Institute of Genetics and Plant Experimental Biology, Academy of Sciences of Uzbekistan. Yuqori Yuz, Qibray region Tashkent district, 111226 Uzbekistan
| | - Lingyan Huang
- Molecular Genetics, Integrated DNA Technologies, 1710 Commercial Park, Coralville, IA, 52241, USA
| | - Abdusalom Makamov
- Center of Genomic Technologies, Institute of Genetics and Plant Experimental Biology, Academy of Sciences of Uzbekistan. Yuqori Yuz, Qibray region Tashkent district, 111226 Uzbekistan
| | - Shukhrat E Shermatov
- Center of Genomic Technologies, Institute of Genetics and Plant Experimental Biology, Academy of Sciences of Uzbekistan. Yuqori Yuz, Qibray region Tashkent district, 111226 Uzbekistan
| | - Tohir Bozorov
- Center of Genomic Technologies, Institute of Genetics and Plant Experimental Biology, Academy of Sciences of Uzbekistan. Yuqori Yuz, Qibray region Tashkent district, 111226 Uzbekistan
| | - Fakhriddin N Kushanov
- Center of Genomic Technologies, Institute of Genetics and Plant Experimental Biology, Academy of Sciences of Uzbekistan. Yuqori Yuz, Qibray region Tashkent district, 111226 Uzbekistan
| | - Gafurjon T Mavlonov
- Center of Genomic Technologies, Institute of Genetics and Plant Experimental Biology, Academy of Sciences of Uzbekistan. Yuqori Yuz, Qibray region Tashkent district, 111226 Uzbekistan
| | - Abdusattor Abdukarimov
- Center of Genomic Technologies, Institute of Genetics and Plant Experimental Biology, Academy of Sciences of Uzbekistan. Yuqori Yuz, Qibray region Tashkent district, 111226 Uzbekistan
| |
Collapse
|