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Cooper CP, Cheng L, Bhatti J, Melendez ER, Huell D, Banuelos C, Perez E, Long JM, Rapp PR. Cerebellum Purkinje cell vulnerability in aged rats with memory impairment. J Comp Neurol 2024; 532:e25610. [PMID: 38605461 PMCID: PMC11027960 DOI: 10.1002/cne.25610] [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: 11/06/2023] [Revised: 01/22/2024] [Accepted: 03/24/2024] [Indexed: 04/13/2024]
Abstract
The cerebellum is involved in higher order cognitive function and is susceptible to age-related atrophy. However, limited evidence has directly examined the cerebellum's role in cognitive aging. To interrogate potential substrates of the relationship between cerebellar structure and memory in aging, here we target the Purkinje cells (PCs). The sole output neurons of the cerebellum, PC loss and/or degeneration underlie a variety of behavioral abnormalities. Using a rat model of normal cognitive aging, we immunostained sections through the cerebellum for the PC-specific protein, calbindin-D28k. Although morphometric quantification revealed no significant difference in total PC number as a function of age or cognitive status, regional cell number was a more robust correlate of memory performance in the young cerebellum than in aged animals. Parallel biochemical analysis of PC-specific protein levels in whole cerebellum additionally revealed that calbindin-D28k and Purkinje cell protein-2 (pcp-2) levels were lower selectively in aged rats with spatial memory impairment compared to both young animals and aged rats with intact memory. These results suggest that cognitive aging is associated with cerebellum vulnerability, potentially reflecting disruption of the cerebellum-medial temporal lobe network.
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Affiliation(s)
- C’iana P. Cooper
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Liam Cheng
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Jafar Bhatti
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Edward R. Melendez
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Derek Huell
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Cristina Banuelos
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Evelyn Perez
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Jeffrey M. Long
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
| | - Peter R. Rapp
- Neurocognitive Aging Section, Laboratory of Behavioral
Neuroscience, National Institute on Aging, Baltimore, Maryland
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Macrì S, Di-Poï N. Heterochronic Developmental Shifts Underlying Squamate Cerebellar Diversity Unveil the Key Features of Amniote Cerebellogenesis. Front Cell Dev Biol 2020; 8:593377. [PMID: 33195265 PMCID: PMC7642464 DOI: 10.3389/fcell.2020.593377] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 09/25/2020] [Indexed: 11/13/2022] Open
Abstract
Despite a remarkable conservation of architecture and function, the cerebellum of vertebrates shows extensive variation in morphology, size, and foliation pattern. These features make this brain subdivision a powerful model to investigate the evolutionary developmental mechanisms underlying neuroanatomical complexity both within and between anamniote and amniote species. Here, we fill a major evolutionary gap by characterizing the developing cerebellum in two non-avian reptile species-bearded dragon lizard and African house snake-representative of extreme cerebellar morphologies and neuronal arrangement patterns found in squamates. Our data suggest that developmental strategies regarded as exclusive hallmark of birds and mammals, including transit amplification in an external granule layer (EGL) and Sonic hedgehog expression by underlying Purkinje cells (PCs), contribute to squamate cerebellogenesis independently from foliation pattern. Furthermore, direct comparison of our models suggests the key importance of spatiotemporal patterning and dynamic interaction between granule cells and PCs in defining cortical organization. Especially, the observed heterochronic shifts in early cerebellogenesis events, including upper rhombic lip progenitor activity and EGL maintenance, are strongly expected to affect the dynamics of molecular interaction between neuronal cell types in snakes. Altogether, these findings help clarifying some of the morphogenetic and molecular underpinnings of amniote cerebellar corticogenesis, but also suggest new potential molecular mechanisms underlying cerebellar complexity in squamates. Furthermore, squamate models analyzed here are revealed as key animal models to further understand mechanisms of brain organization.
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Affiliation(s)
- Simone Macrì
- Program in Developmental Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Nicolas Di-Poï
- Program in Developmental Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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3
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Serrano-Saiz E, Leyva-Díaz E, De La Cruz E, Hobert O. BRN3-type POU Homeobox Genes Maintain the Identity of Mature Postmitotic Neurons in Nematodes and Mice. Curr Biol 2018; 28:2813-2823.e2. [PMID: 30146154 DOI: 10.1016/j.cub.2018.06.045] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 06/08/2018] [Accepted: 06/19/2018] [Indexed: 11/28/2022]
Abstract
Many distinct regulatory factors have been shown to be required for the proper initiation of neuron-type-specific differentiation programs, but much less is known about the regulatory programs that maintain the differentiated state in the adult [1-3]. One possibility is that regulatory factors that initiate a terminal differentiation program during development are continuously required to maintain the differentiated state. Here, we test this hypothesis by investigating the function of two orthologous POU homeobox genes in nematodes and mice. The C. elegans POU homeobox gene unc-86 is a terminal selector that is required during development to initiate the terminal differentiation program of several distinct neuron classes [4-13]. Through post-developmental removal of unc-86 activity, we show here that unc-86 is also continuously required throughout the life of many neuron classes to maintain neuron-class-specific identity features. Similarly, the mouse unc-86 ortholog Brn3a/POU4F1 has been shown to control the initiation of the terminal differentiation program of distinct neuron types across the mouse brain, such as the medial habenular neurons [14-20]. By conditionally removing Brn3a in the adult mouse central nervous system, we show that, like its invertebrate ortholog unc-86, Brn3a is also required for the maintenance of terminal identity features of medial habenular neurons. In addition, Brn3a is required for the survival of these neurons, indicating that identity maintenance and survival are genetically linked. We conclude that the continuous expression of transcription factors is essential for the active maintenance of the differentiated state of a neuron across phylogeny.
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Affiliation(s)
- Esther Serrano-Saiz
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY, USA.
| | - Eduardo Leyva-Díaz
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Estanislao De La Cruz
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY, USA.
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4
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Zanjani HS, Vogel MW, Mariani J. Deletion of the GluRδ2 Receptor in the Hotfoot Mouse Mutant Causes Granule Cell Loss, Delayed Purkinje Cell Death, and Reductions in Purkinje Cell Dendritic Tree Area. THE CEREBELLUM 2017; 15:755-766. [PMID: 26607150 DOI: 10.1007/s12311-015-0748-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Recent studies have found that in the cerebellum, the δ2 glutamate receptor (GluRδ2) plays a key role in regulating the differentiation of parallel fiber-Purkinje synapses and mediating key physiological functions in the granule cell-Purkinje cell circuit. In the hotfoot mutant or GluRδ2 knockout mice, the absence of GluRδ2 expression results in impaired motor-related tasks, ataxia, and disruption of long-term depression at parallel fiber-Purkinje cell synapses. The goal of this study was to determine the long-term consequences of deletion of GluRδ2 expression in the hotfoot mutant (GluRδ2 ho/ho ) on Purkinje and granule cell survival and Purkinje cell dendritic differentiation. Quantitative estimates of Purkinje and granule cell numbers in 3-, 12-, and 20-month-old hotfoot mutants and wild-type controls showed that Purkinje cell numbers are within control values at 3 and 12 months in the hotfoot mutant but reduced by 20 % at 20 months compared with controls. In contrast, the number of granule cells is significantly reduced from 3 months onwards in GluRδ2 ho/ho mutant mice compared to wild-type controls. Although the overall structure of Purkinje cell dendrites does not appear to be altered, there is a significant 27 % reduction in the cross-sectional area of Purkinje cell dendritic trees in the 20-month-old GluRδ2 ho/ho mutants. The interpretation of the results is that the GluRδ2 receptor plays an important role in the long-term organization of the granule-Purkinje cell circuit through its involvement in the regulation of parallel fiber-Purkinje cell synaptogenesis and in the normal functioning of this critical cerebellar circuit.
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Affiliation(s)
- Hadi S Zanjani
- Sorbonne Universités UPMC Univ. Paris 06, IBPS, UMR 8256, Biological Adaptation and Ageing, B2A, 75005, Paris, France.,CNRS, UMR 8256, B2A, F-75005, Paris, France
| | - Michael W Vogel
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD, 21228, USA.
| | - Jean Mariani
- Sorbonne Universités UPMC Univ. Paris 06, IBPS, UMR 8256, Biological Adaptation and Ageing, B2A, 75005, Paris, France.,CNRS, UMR 8256, B2A, F-75005, Paris, France.,Institut de la Longévité, APHP, DHU Fast, 94205, Ivry-Sur-Seine, France
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5
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Cell Death as a Regulator of Cerebellar Histogenesis and Compartmentation. THE CEREBELLUM 2010; 10:373-92. [DOI: 10.1007/s12311-010-0222-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Heitz S, Gautheron V, Lutz Y, Rodeau JL, Zanjani HS, Sugihara I, Bombarde G, Richard F, Fuchs JP, Vogel MW, Mariani J, Bailly Y. BCL-2 counteracts Doppel-induced apoptosis of prion-protein-deficient Purkinje cells in the Ngsk Prnp(0/0) mouse. Dev Neurobiol 2008; 68:332-48. [PMID: 18085563 DOI: 10.1002/dneu.20555] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The pro-apoptotic factor BAX has recently been shown to contribute to Purkinje cell (PC) apoptosis induced by the neurotoxic prion-like protein Doppel (Dpl) in the prion-protein-deficient Ngsk Prnp(0/0) (NP(0/0)) mouse. In view of cellular prion protein (PrP(c)) ability to counteract Dpl neurotoxicity and favor neuronal survival like BCL-2, we investigated the effects of the anti-apoptotic factor BCL-2 on Dpl neurotoxicity by studying the progression of PC death in aging NP(0/0)-Hu-bcl-2 double mutant mice overexpressing human BCL-2 (Hu-bcl-2). Quantitative analysis showed that significantly more PCs survived in NP(0/0)-Hu-bcl-2 double mutants compared with the NP(0/0) mutants. However, number of PCs remained inferior to wild-type levels and to the increased number of PCs observed in Hu-bcl-2 mutants. In the NP(0/0) mutants, Dpl-induced PC death occurred preferentially in the aldolase C-negative parasagittal compartments of the cerebellar cortex. Activation of glial cells exclusively in these compartments, which was abolished by the expression of Hu-bcl-2 in the double mutants, suggested that chronic inflammation is an indirect consequence of Dpl-induced PC death. This partial rescue of NP(0/0) PCs by Hu-bcl-2 expression was similar to that observed in NP(0/0):Bax(-/-) double mutants with bax deletion. Taken together, these data strongly support the involvement of BCL-2 family-dependent apoptotic pathways in Dpl neurotoxicity. The capacity of BCL-2 to compensate PrP(c) deficiency by rescuing PCs from Dpl-induced death suggests that the BCL-2-like property of PrP(c) may impair Dpl-like neurotoxic pathways in wild-type neurons.
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Affiliation(s)
- S Heitz
- Département Neurotransmission et Sécrétion Neuroendocrine, UMR7168-LC2 CNRS, France.
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Magrassi L, Grimaldi P, Ibatici A, Corselli M, Ciardelli L, Castello S, Podestà M, Frassoni F, Rossi F. Induction and survival of binucleated Purkinje neurons by selective damage and aging. J Neurosci 2007; 27:9885-92. [PMID: 17855603 PMCID: PMC6672639 DOI: 10.1523/jneurosci.2539-07.2007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Fusion of bone marrow-derived cells with adult Purkinje cells in the cerebellum gives rise to binucleated Purkinje cells. Whether fusion can be modulated by epigenetic factors and whether fused neurons are stable has remained unclear. Here, we show that in mice and rats, partial ablation of Purkinje cells and local microglial activation in the absence of structural damage to the cerebellum increase the rate of fusion. Moreover, mouse Purkinje cells once fused with bone marrow-derived cells are viable for at least 7 months. We also show that cerebellar irradiation is unnecessary for the generation of binucleated Purkinje cells after bone marrow grafting. Moreover, binucleated Purkinje cells can be found in aged mice that did not receive any treatment, suggesting that fusion events occasionally occur throughout the whole lifespan of healthy, unmanipulated individuals. However, in aged chimeric mice that, after bone marrow transplant, have the majority of their nucleated blood cells fluorescent, the number of binucleated fluorescent Purkinje cells is two orders of magnitude less than the total number of binucleated Purkinje cells. This suggests that, in the majority of heterokaryons, either the incoming nucleus is quickly inactivated or fusion is not the only way to generate a binucleated Purkinje cell.
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Affiliation(s)
- Lorenzo Magrassi
- Neurochirurgia Dipartimento Scienze Chirurgiche, Università di Pavia, Fondazione Instituto di Ricovero e Curaio a Carattere Scientifico Policlinico S. Matteo, 27100 Pavia, Italy.
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8
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Heitz S, Lutz Y, Rodeau JL, Zanjani H, Gautheron V, Bombarde G, Richard F, Fuchs JP, Vogel MW, Mariani J, Bailly Y. BAX contributes to Doppel-induced apoptosis of prion-protein-deficient Purkinje cells. Dev Neurobiol 2007; 67:670-86. [PMID: 17443816 DOI: 10.1002/dneu.20366] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Research efforts to deduce the function of the prion protein (PrPc) in knock-out mouse mutants have revealed that large deletions in the PrPc genome result in the ectopic neuronal expression of the prion-like protein Doppel (Dpl). In our analysis of one such line of mutant mice, Ngsk Prnp0/0 (NP0/0), we demonstrate that the ectopic expression of Dpl in brain neurons induces significant levels of cerebellar Purkinje cell (PC) death as early as six months after birth. To investigate the involvement of the mitochondrial proapoptotic factor BAX in the Dpl-induced apoptosis of PCs, we have analyzed the progression of PC death in aging NP0/0:Bax-/- double knockout mutants. Quantitative analysis of cell numbers showed that significantly more PCs survived in NP0/0:Bax-/- double mutants than in the NP0/0:Bax+/+ mutants. However, PC numbers were not restored to wildtype levels or to the increased number of PCs observed in Bax-/- mutants. The partial rescue of NP0/0 PCs suggests that the ectopic expression of Dpl induces both BAX-dependent and BAX-independent pathways of cell death. The activation of glial cells that is shown to be associated topographically with Dpl-induced PC death in the NP0/0:Bax+/+ mutants is abolished by the loss of Bax expression in the double mutant mice, suggesting that chronic inflammation is an indirect consequence of Dpl-induced PC death.
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Affiliation(s)
- S Heitz
- Département Neurotransmission et Sécrétion Neuroendocrine, Institut des Neurosciences Cellulaires et Intégratives (UMR7168-LC2), CNRS/Université Louis Pasteur, IFR 37 des Neurosciences de Strasbourg, and APHP, Hôpital Charles Foix, Ivry/Seine, France
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9
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Rutten BPF, Schmitz C, Gerlach OHH, Oyen HM, de Mesquita EB, Steinbusch HWM, Korr H. The aging brain: Accumulation of DNA damage or neuron loss? Neurobiol Aging 2007; 28:91-8. [PMID: 16338029 DOI: 10.1016/j.neurobiolaging.2005.10.019] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2005] [Revised: 10/25/2005] [Accepted: 10/27/2005] [Indexed: 12/22/2022]
Abstract
Age-related molecular and cellular alterations in the central nervous system are known to show selectivity for certain cell types and brain regions. Among them age-related accumulation of nuclear (n) DNA damage can lead to irreversible loss of genetic information content. In the present study on the aging mouse brain, we observed a substantial increase in the amount of nDNA single-strand breaks in hippocampal pyramidal and granule cells as well as in cerebellar granule cells but not in cerebellar Purkinje cells. The reverse pattern was found for age-related reductions in total numbers of neurons. Only the total number of cerebellar Purkinje cells was significantly reduced during aging whereas the total numbers of hippocampal pyramidal and granule cells as well as of cerebellar granule cells were not. This formerly unknown inverse relation between age-related accumulation of nDNA damage and age-related loss of neurons may reflect a fundamental process of aging in the central nervous system.
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Affiliation(s)
- Bart P F Rutten
- Department of Psychiatry and Neuropsychology, Division of Cellular Neuroscience, Maastricht University, Universiteitssingel 50, 6200 MD Maastricht, The Netherlands
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10
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Dusart I, Guenet JL, Sotelo C. Purkinje cell death: differences between developmental cell death and neurodegenerative death in mutant mice. THE CEREBELLUM 2006; 5:163-73. [PMID: 16818391 DOI: 10.1080/14734220600699373] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This review is devoted to Purkinje cell death occurring during development and in spontaneous cerebellar mutations of the mouse. We first present evidence in favor of an apoptotic developmental Purkinje cell death. Then, the different types of Purkinje cell degeneration occurring in mutant mice primarily affecting this neuronal population (nervous, purkinje cell degeneration, Lurcher, toppler, and woozy) are described and discussed. In addition, we show, by reporting new data, that cell death in tambaleante mutant mice can be related to autophagy. Last, we discuss the fact that the cell death pathways in mutant mice are more complex than the three types of developmental death generally described (apoptosis, autophagy, necrosis), since they share often characteristics of more than one type of these developmental cell deaths, particularly autophagy and apoptosis.
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11
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Yamanaka K, Miller TM, McAlonis-Downes M, Chun SJ, Cleveland DW. Progressive spinal axonal degeneration and slowness in ALS2-deficient mice. Ann Neurol 2006; 60:95-104. [PMID: 16802286 DOI: 10.1002/ana.20888] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Homozygous mutation in the ALS2 gene and the resulting loss of the guanine exchange factor activity of the ALS2 protein is causative for autosomal recessive early-onset motor neuron disease that is thought to predominantly affect upper motor neurons. The goal of this study was to elucidate how the motor system is affected by the deletion of ALS2. METHODS ALS2-deficient mice were generated by gene targeting. Motor function and upper and lower motor neuron pathology were examined in ALS2-deficient mice and in mutant superoxide dismutase 1 (SOD1) mice that develop ALS-like disease from expression of an ALS-linked mutation in SOD1. RESULTS ALS2-deficient mice demonstrated progressive axonal degeneration in the lateral spinal cord that is also prominent in mutant SOD1 mice. Despite the vulnerability of these spinal axons, lower motor neurons in ALS2-deficient mice were preserved. Behavioral studies demonstrated slowed movement without muscle weakness in ALS2(-/-) mice, consistent with upper motor neuron defects that lead to spasticity in humans. INTERPRETATION The combined evidence from mice and humans shows that deficiency in ALS2 causes an upper motor neuron disease that in humans closely resembles a severe form of hereditary spastic paralysis, and that is quite distinct from amyotrophic lateral sclerosis.
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Affiliation(s)
- Koji Yamanaka
- Ludwig Institute for Cancer Research and Department of Medicine and Neurosciences, University of California, San Diego, La Jolla, 92093-0670, USA.
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12
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Han M, Schottler F, Lei D, Dong EY, Bryan A, Bao J. Bcl-2 over-expression fails to prevent age-related loss of calretinin positive neurons in the mouse dentate gyrus. Mol Neurodegener 2006; 1:9. [PMID: 16930456 PMCID: PMC1569830 DOI: 10.1186/1750-1326-1-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2006] [Accepted: 08/22/2006] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Cognitive performance declines with increasing age. Possible cellular mechanisms underlying this age-related functional decline remain incompletely understood. Early studies attributed this functional decline to age-related neuronal loss. Subsequent studies using unbiased stereological techniques found little or no neuronal loss during aging. However, studies using specific cellular markers found age-related loss of specific neuronal types. To test whether there is age-related loss of specific neuronal populations in the hippocampus, and subsequently, whether over-expression of the B-cell lymphoma protein-2 (Bcl-2) in these neurons could delay possible age-related neuronal loss, we examined calretinin (CR) positive neurons in the mouse dentate gyrus during aging. RESULT In normal mice, there was an age-related loss of CR positive cells in the dentate gyrus. At the same region, there was no significant decrease of total numbers of neurons, which suggested that age-related loss of CR positive cells was due to the decrease of CR expression in these cells instead of cell death. In the transgenic mouse line over-expressing Bcl-2 in neurons, there was an age-related loss of CR positive cells. Interestingly, there was also an age-related neuronal loss in this transgenic mouse line. CONCLUSION These data suggest an age-related loss of CR positive neurons but not total neuronal loss in normal mice and this age-related neuronal change is not prevented by Bcl-2 over-expression.
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Affiliation(s)
- Mingbo Han
- Department of Otolaryngology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Frank Schottler
- Department of Otolaryngology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Debin Lei
- Department of Otolaryngology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Elizabeth Y Dong
- Department of Otolaryngology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Alexander Bryan
- Department of Otolaryngology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Jianxin Bao
- Department of Otolaryngology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
- Center for Aging, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
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Abstract
The programmed cell death (PCD) of developing cells is considered an essential adaptive process that evolved to serve diverse roles. We review the putative adaptive functions of PCD in the animal kingdom with a major focus on PCD in the developing nervous system. Considerable evidence is consistent with the role of PCD in events ranging from neurulation and synaptogenesis to the elimination of adult-generated CNS cells. The remarkable recent progress in our understanding of the genetic regulation of PCD has made it possible to perturb (inhibit) PCD and determine the possible repercussions for nervous system development and function. Although still in their infancy, these studies have so far revealed few striking behavioral or functional phenotypes.
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Affiliation(s)
- Robert R Buss
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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14
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Zanjani SH, Selimi F, Vogel MW, Haeberlé AM, Boeuf J, Mariani J, Bailly YJ. Survival of interneurons and parallel fiber synapses in a cerebellar cortex deprived of Purkinje cells: Studies in the double mutant mouseGrid2Lc/+;Bax−/−. J Comp Neurol 2006; 497:622-35. [PMID: 16739195 DOI: 10.1002/cne.21017] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The Lurcher mutation in the Grid2 gene causes the cell autonomous death of virtually all cerebellar Purkinje cells and the target-related death of 90% of the granule cells and 60-75% of the olivary neurons. Inactivation of Bax, a pro-apoptotic gene of the Bcl-2 family, in heterozygous Lurcher mutants (Grid2Lc/+) rescues approximately 60% of the granule cells, but does not rescue Purkinje or olivary neurons. Given the larger size of the cerebellar molecular layer in Grid2Lc/+;Bax(-/-) double mutants compared to Grid2Lc/+ mutants, we analyzed the survival of the stellate and basket interneurons as well as the synaptic connectivity of parallel fibers originating from the surviving granule cells in the absence of their Purkinje cell targets in the Grid2Lc/+;Bax(-/-) cerebellum. Quantification showed a significantly higher density of interneurons ( approximately 60%) in the molecular layer of the Grid2Lc/+;Bax(-/-) mice compared to Grid2Lc/+, suggesting that interneurons are subject to a BAX-dependent target-related death in the Lurcher mutants. Furthermore, electron microscopy showed the normal ultrastructural aspect of a number of parallel fibers in the molecular layer of the Grid2Lc/+; Bax(-/-) double mutant mice and preserved their numerous synaptic contacts on interneurons, suggesting that interneurons could play a trophic role for axon terminals of surviving granule cells. Finally, parallel fibers varicosities in the double mutant established "pseudo-synapses" on glia as well as displayed autophagic profiles, suggesting that the connections established by the parallel fibers in the absence of their Purkinje cell targets were subject to a high turnover involving autophagy.
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Affiliation(s)
- S Hadi Zanjani
- Equipe Développement et Vieillissement du Système Nerveux, UMR NPA 7102 CNRS et Univ. P. & M. Curie, 75005 Paris, France
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15
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Hadano S, Benn SC, Kakuta S, Otomo A, Sudo K, Kunita R, Suzuki-Utsunomiya K, Mizumura H, Shefner JM, Cox GA, Iwakura Y, Brown RH, Ikeda JE. Mice deficient in the Rab5 guanine nucleotide exchange factor ALS2/alsin exhibit age-dependent neurological deficits and altered endosome trafficking. Hum Mol Genet 2005; 15:233-50. [PMID: 16321985 DOI: 10.1093/hmg/ddi440] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
ALS2/alsin is a member of guanine nucleotide exchange factors for the small GTPase Rab5 (Rab5GEFs), which act as modulators in endocytic pathway. Loss-of-function mutations in human ALS2 account for a number of juvenile recessive motor neuron diseases (MNDs). However, the normal physiological role of ALS2 in vivo and the molecular mechanisms underlying motor dysfunction are still unknown. To address these issues, we have generated mice homozygous for disruption of the Als2 gene. The Als2-null mice observed through 21 months of age demonstrated no obvious developmental, reproductive or motor abnormalities. However, immunohistochemical and electrophysiological analyses identified an age-dependent, slowly progressive loss of cerebellar Purkinje cells and disturbance of spinal motor neurons associated with astrocytosis and microglial cell activation, indicating a subclinical dysfunction of motor system in Als2-null mice. Further, quantitative epidermal growth factor (EGF)-uptake analysis identified significantly smaller-sized EGF-positive endosomes in Als2-null fibroblasts, suggesting an alteration of endosome/vesicle trafficking in the cells. Collectively, while loss of ALS2 does not produce a severe disease phenotype in mice, these Als2-null animals should provide a useful model with which to understand the interplay between endosomal dynamics and the long-term viability of large neurons such as Purkinje cells and spinal motor neurons.
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Affiliation(s)
- Shinji Hadano
- Department of Molecular Neuroscience, The Institute of Medical Sciences, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan
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Abstract
The consequences of eliminating the process of programmed cell death during the development of the nervous system is examined by reviewing studies in the genetic model organisms Caenorhabditis elegans, Drosophila melanogaster, Danio rerio and Mus musculus, where mutations of cell death genes have eliminated or reduced programmed cell death in the nervous system. In many cases, genetic elimination of cell death leads to embryonic mortality or gross anatomical malformations; however, there are cases where animals develop normally but with excess neurons and glia in the nervous system. Undead cells either differentiate and function as working neurons, in some instances being of smaller size, or fail to differentiate and lack normal connections with their targets. Changes in motor control and sensory processing are generally not observed, except for during the most complex of behaviors. Examination of organisms where death genes have been genetically eliminated reveals that programmed cell death may play an important role in sculpting gross brain structure during early development of the neural tube. In contrast, the consequences of preventing neuronal cell death at later developmental stages (e.g. during vertebrate synapse formation) are just beginning to be understood.
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Affiliation(s)
- Robert R Buss
- Department of Neurobiology and Anatomy and the Neuroscience Program, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1010, USA
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