1
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Sellinger EP, Brinks AS, Javeri RR, Theurer SL, Wang R, Juraska JM. Region- and age-specific effects of perinatal phthalate exposure on developmental cell death and adult anatomy of dorsal and ventral hippocampus and associated cognitive behaviors. Neurotoxicol Teratol 2023; 99:107288. [PMID: 37595675 PMCID: PMC10530334 DOI: 10.1016/j.ntt.2023.107288] [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: 02/16/2023] [Revised: 08/01/2023] [Accepted: 08/10/2023] [Indexed: 08/20/2023]
Abstract
Humans are exposed to phthalates, a class of endocrine-disrupting chemicals used in food packaging/processing, PVC plastics, and personal care products. Gestational exposure may lead to adverse neurodevelopmental outcomes. In a rat model, perinatal exposure to an environmentally relevant mixture and dose of phthalates leads to increased developmental apoptosis in the medial prefrontal cortex (mPFC) and a subsequent reduction in neurons and in cognitive flexibility measured in adults of both sexes (Sellinger et al., 2021b; Kougias et al., 2018b). However, whether these effects generalize to other cognitive regions, like the hippocampus, is less well understood as existing studies used single phthalates at large doses, unrepresentative of human exposure. In the current study, patterns of naturally occurring cell death were first established in the dorsal and ventral hippocampal subfields (CA3 and CA1). Both dorsal and ventral CA3 reached high levels of cell death on P2 while levels in dorsal and ventral CA1 peaked on P5 in both sexes. Exposure to a phthalate mixture (0.2 and 1 mg/kg/day) throughout gestation through postnatal day 10 resulted in subtle age- and region-specific decreases in developmental cell death, however there were no significant changes in adult neuron number or associated behaviors: the Morris water maze and social recognition. Therefore, perinatal exposure to a low dose mixture of phthalates does not result in the dramatic structural and behavioral changes seen with high doses of single phthalates. This study also adds to our understanding of the distinct neurodevelopmental effects of phthalates on different brain regions.
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Affiliation(s)
- Elli P Sellinger
- Neuroscience Program, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, United States of America.
| | - Amara S Brinks
- Neuroscience Program, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, United States of America.
| | - Rajvi R Javeri
- Department of Psychology, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, United States of America.
| | - Savannah L Theurer
- Department of Psychology, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, United States of America.
| | - Ruibin Wang
- Department of Psychology, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, United States of America.
| | - Janice M Juraska
- Neuroscience Program, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, United States of America; Department of Psychology, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, United States of America.
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2
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Griffioen G. Calcium Dyshomeostasis Drives Pathophysiology and Neuronal Demise in Age-Related Neurodegenerative Diseases. Int J Mol Sci 2023; 24:13243. [PMID: 37686048 PMCID: PMC10487569 DOI: 10.3390/ijms241713243] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 08/21/2023] [Accepted: 08/23/2023] [Indexed: 09/10/2023] Open
Abstract
This review postulates that age-related neurodegeneration entails inappropriate activation of intrinsic pathways to enable brain plasticity through deregulated calcium (Ca2+) signalling. Ca2+ in the cytosol comprises a versatile signal controlling neuronal cell physiology to accommodate adaptive structural and functional changes of neuronal networks (neuronal plasticity) and, as such, is essential for brain function. Although disease risk factors selectively affect different neuronal cell types across age-related neurodegenerative diseases (NDDs), these appear to have in common the ability to impair the specificity of the Ca2+ signal. As a result, non-specific Ca2+ signalling facilitates the development of intraneuronal pathophysiology shared by age-related NDDs, including mitochondrial dysfunction, elevated reactive oxygen species (ROS) levels, impaired proteostasis, and decreased axonal transport, leading to even more Ca2+ dyshomeostasis. These core pathophysiological processes and elevated cytosolic Ca2+ levels comprise a self-enforcing feedforward cycle inevitably spiralling toward high levels of cytosolic Ca2+. The resultant elevated cytosolic Ca2+ levels ultimately gear otherwise physiological effector pathways underlying plasticity toward neuronal demise. Ageing impacts mitochondrial function indiscriminately of the neuronal cell type and, therefore, contributes to the feedforward cycle of pathophysiology development seen in all age-related NDDs. From this perspective, therapeutic interventions to safely restore Ca2+ homeostasis would mitigate the excessive activation of neuronal destruction pathways and, therefore, are expected to have promising neuroprotective potential.
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3
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Carotenuto R, Pallotta MM, Tussellino M, Fogliano C. Xenopus laevis (Daudin, 1802) as a Model Organism for Bioscience: A Historic Review and Perspective. BIOLOGY 2023; 12:890. [PMID: 37372174 DOI: 10.3390/biology12060890] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 06/15/2023] [Accepted: 06/20/2023] [Indexed: 06/29/2023]
Abstract
In vitro systems have been mainly promoted by authorities to sustain research by following the 3Rs principle, but continuously increasing amounts of evidence point out that in vivo experimentation is also of extreme relevance. Xenopus laevis, an anuran amphibian, is a significant model organism in the study of evolutionary developmental biology, toxicology, ethology, neurobiology, endocrinology, immunology and tumor biology; thanks to the recent development of genome editing, it has also acquired a relevant position in the field of genetics. For these reasons, X. laevis appears to be a powerful and alternative model to the zebrafish for environmental and biomedical studies. Its life cycle, as well as the possibility to obtain gametes from adults during the whole year and embryos by in vitro fertilization, allows experimental studies of several biological endpoints, such as gametogenesis, embryogenesis, larval growth, metamorphosis and, of course, the young and adult stages. Moreover, with respect to alternative invertebrate and even vertebrate animal models, the X. laevis genome displays a higher degree of similarity with that of mammals. Here, we have reviewed the main available literature on the use of X. laevis in the biosciences and, inspired by Feymann's revised view, "Plenty of room for biology at the bottom", suggest that X. laevis is a very useful model for all possible studies.
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Affiliation(s)
- Rosa Carotenuto
- Department of Biology, University of Naples Federico II, 80126 Naples, Italy
| | | | | | - Chiara Fogliano
- Department of Biology, University of Naples Federico II, 80126 Naples, Italy
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4
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Ahmad I, Subramani M. Microglia: Friends or Foes in Glaucoma? A Developmental Perspective. Stem Cells Transl Med 2022; 11:1210-1218. [PMID: 36426733 PMCID: PMC9801300 DOI: 10.1093/stcltm/szac077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 09/29/2022] [Indexed: 11/27/2022] Open
Abstract
Glaucoma is the most prevalent form of optic neuropathy where a progressive degeneration of retinal ganglion cells (RGCs) leads to irreversible loss of vision. The mechanism underlying glaucomatous degeneration remains poorly understood. However, evidence suggests that microglia, which regulate RGC numbers and synaptic integrity during development and provide homeostatic support in adults, may contribute to the disease process. Hence, microglia represent a valid cellular target for therapeutic approaches in glaucoma. Here, we provide an overview of the role of microglia in RGC development and degeneration in the backdrop of neurogenesis and neurodegeneration in the central nervous system and discuss how pathological recapitulation of microglia-mediated developmental mechanisms may help initiate or exacerbate glaucomatous degeneration.
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Affiliation(s)
- Iqbal Ahmad
- Corresponding author: Iqbal Ahmad, Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Murali Subramani
- Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA
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5
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Erxian decoction inhibits apoptosis by activating Akt1 and repairs spinal cord injury in rats. Heliyon 2022; 8:e11279. [DOI: 10.1016/j.heliyon.2022.e11279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/26/2022] [Accepted: 10/20/2022] [Indexed: 11/06/2022] Open
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6
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Nagata T, Shinagawa S, Nakajima S, Noda Y, Mimura M. Pharmacotherapeutic combinations for the treatment of Alzheimer's disease. Expert Opin Pharmacother 2022; 23:727-737. [PMID: 35230200 DOI: 10.1080/14656566.2022.2042514] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Alzheimer's disease (AD) is the most common form of dementia, and four medications are currently available as symptomatic therapies: three cholinesterase inhibitors (ChEI) and memantine. In June 2021, aducanumab was approved in the United States under an accelerated approval pathway as the first novel putative disease-modifying therapy (p-DMT) targeting the β-amyloid (Aβ) cascade in the brain. The combination of several monotherapies to address the multifactorial pathogenesis of neurodegenerative diseases is an anticipated next step. AREAS COVERED The cholinergic hypothesis and the amyloid cascade hypothesis have been proposed as explanations for the pathogenesis of AD. Given the limited effectiveness of monotherapies based on these hypotheses, approaches using combination therapy are attempting to address the complexity of AD pathogenesis, including putative causative proteins-related neurodegeneration, neurotransmitters, and neuroinflammation, in a comprehensive manner. EXPERT OPINION The efficacy of an initial or add-on combination approach to counteracting neurodegenerative processes and functional deterioration has been investigated. The combination of symptomatic therapies with approved anti-dementia medicines (one ChEI and memantine) has been found to be functionally effective for a moderately severe disease stage. Furthermore, combination strategies involving p-DMTs, symptomatic therapies, and neuro-regeneration may be useful in the future.
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Affiliation(s)
- Tomoyuki Nagata
- Department of Psychiatry, The Jikei University School of Medicine, Tokyo, Japan.,Department of Psychiatry, Airanomori Hospital, Kagoshima, Japan
| | | | - Shinichiro Nakajima
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Yoshihiro Noda
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Masaru Mimura
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
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7
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Coccia E, Solé M, Comella JX. FAIM-L - SIVA-1: Two Modulators of XIAP in Non-Apoptotic Caspase Function. Front Cell Dev Biol 2022; 9:826037. [PMID: 35083225 PMCID: PMC8784879 DOI: 10.3389/fcell.2021.826037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 12/20/2021] [Indexed: 11/13/2022] Open
Abstract
Apoptosis is crucial for the correct development of the nervous system. In adulthood, the same protein machinery involved in programmed cell death can control neuronal adaptiveness through modulation of synaptic pruning and synaptic plasticity processes. Caspases are the main executioners in these molecular pathways, and their strict regulation is essential to perform neuronal remodeling preserving cell survival. FAIM-L and SIVA-1 are regulators of caspase activation. In this review we will focus on FAIM-L and SIVA-1 as two functional antagonists that modulate non-apoptotic caspase activity in neurons. Their participation in long-term depression and neurite pruning will be described in base of the latest studies performed. In addition, the association of FAIM-L non-apoptotic functions with the neurodegeneration process will be reviewed.
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Affiliation(s)
- Elena Coccia
- Cell Signaling and Apoptosis Group, Vall d'Hebron Institute of Research (VHIR), Barcelona, Spain.,Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain.,Departament de Bioquímica I Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain
| | - Montse Solé
- Cell Signaling and Apoptosis Group, Vall d'Hebron Institute of Research (VHIR), Barcelona, Spain.,Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain.,Departament de Bioquímica I Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain
| | - Joan X Comella
- Cell Signaling and Apoptosis Group, Vall d'Hebron Institute of Research (VHIR), Barcelona, Spain.,Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain.,Departament de Bioquímica I Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain
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8
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Li X, Lin G, Liu T, Zhao N, Xu H, Wang H, Zheng W. Postnatal development of BAG3 expression in mouse cerebral cortex and hippocampus. Brain Struct Funct 2021; 226:2629-2650. [PMID: 34357438 DOI: 10.1007/s00429-021-02356-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 07/26/2021] [Indexed: 10/20/2022]
Abstract
The decreased efficiency of autophagic processing in the central nervous system during aging may be a contributing factor in neurodegenerative diseases. BAG3 (Bcl2 associated athanogene 3) is a major member of the BAG family of co-molecular chaperones that mediate selective macroautophagy. Therefore, we analyzed the expression and distribution of BAG3 in the brain at postnatal 0 day (P0), P15, 1-, 2-, 9-, 12-, and 18 month-old C57BL/6 mice, thus covering almost all ages. Except for a significant steep drop in mRNA and protein levels in the cortex and hippocampus soon after birth, there were minimal differences in the expression and distribution of BAG3 among P15, M1, M2, M9, and M12 mice; however, at 18 months, BAG3 expression was significantly higher. Immunohistochemical analyses showed that BAG3 is mainly located in the neuronal cytoplasm and processes in C57BL/6 the cerebral cortex and hippocampus from P0 to M18 postnatal development. These findings indicate that BAG3 might be stable in young and middle-aged mice, but unstable in aged mice.
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Affiliation(s)
- Xinlu Li
- Department of Histology and Embryology, China Medical University, Shenyang, 110122, China
| | - Geng Lin
- Department of Histology and Embryology, China Medical University, Shenyang, 110122, China
| | - Tongtong Liu
- Department of Histology and Embryology, China Medical University, Shenyang, 110122, China.,Department of Neurology, The People's Hospital of Liaoning Province, Shenyang, 110016, China
| | - Ning Zhao
- Department of Infectious Diseases, Shengjing Hospital, Affiliated Hospital of China Medical University, Shenyang, 110022, China
| | - He Xu
- Department of Histology and Embryology, School of Medicine, Shenzhen University, Shenzhen, 518052, China
| | - Huaqin Wang
- Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, 110122, China
| | - Wei Zheng
- Department of Histology and Embryology, China Medical University, Shenyang, 110122, China.
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9
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Kuboki A, Kikuta S, Otori N, Kojima H, Matsumoto I, Reisert J, Yamasoba T. Insulin-Dependent Maturation of Newly Generated Olfactory Sensory Neurons after Injury. eNeuro 2021; 8:ENEURO.0168-21.2021. [PMID: 33906971 PMCID: PMC8143024 DOI: 10.1523/eneuro.0168-21.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 04/20/2021] [Indexed: 12/24/2022] Open
Abstract
Loss of olfactory sensory neurons (OSNs) after injury to the olfactory epithelium (OE) triggers the generation of OSNs that are incorporated into olfactory circuits to restore olfactory sensory perception. This study addresses how insulin receptor-mediated signaling affects the functional recovery of OSNs after OE injury. Insulin levels were reduced in mice by ablating the pancreatic β cells via streptozotocin (STZ) injections. These STZ-induced diabetic and control mice were then intraperitoneally injected with the olfactotoxic drug methimazole to selectively ablate OSNs. The OE of diabetic and control mice regenerated similarly until day 14 after injury. Thereafter, the OE of diabetic mice contained fewer mature and more apoptotic OSNs than control mice. Functionally, diabetic mice showed reduced electro-olfactogram (EOG) responses and their olfactory bulbs (OBs) had fewer c-Fos-active cells following odor stimulation, as well as performed worse in an odor-guided task compared with control mice. Insulin administered intranasally during days 8-13 after injury was sufficient to rescue recovery of OSNs in diabetic mice compared with control levels, while insulin administration between days 1 and 6 did not. During this critical time window on days 8-13 after injury, insulin receptors are highly expressed and intranasal application of an insulin receptor antagonist inhibits regeneration. Furthermore, an insulin-enriched environment could facilitate regeneration even in non-diabetic mice. These results indicate that insulin facilitates the regeneration of OSNs after injury and suggest a critical stage during recovery (8-13 d after injury) during which the maturation of newly generated OSNs is highly dependent on and promoted by insulin.
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Affiliation(s)
- Akihito Kuboki
- Department of Otolaryngology, Jikei University School of Medicine, Tokyo 105-8461, Japan
- Monell Chemical Senses Center, Philadelphia, PA 19104
| | - Shu Kikuta
- Department of Otolaryngology, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655, Japan
| | - Nobuyoshi Otori
- Department of Otolaryngology, Jikei University School of Medicine, Tokyo 105-8461, Japan
| | - Hiromi Kojima
- Department of Otolaryngology, Jikei University School of Medicine, Tokyo 105-8461, Japan
| | | | | | - Tatsuya Yamasoba
- Department of Otolaryngology, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655, Japan
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10
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NGF-Dependent and BDNF-Dependent DRG Sensory Neurons Deploy Distinct Degenerative Signaling Mechanisms. eNeuro 2021; 8:ENEURO.0277-20.2020. [PMID: 33372032 PMCID: PMC7877462 DOI: 10.1523/eneuro.0277-20.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 02/07/2023] Open
Abstract
The nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are trophic factors required by distinct population of sensory neurons during development of the nervous system. Neurons that fail to receive appropriate trophic support are lost during this period of naturally occurring cell death. In the last decade, our understanding of the signaling pathways regulating neuronal death following NGF deprivation has advanced substantially. However, the signaling mechanisms promoting BDNF deprivation-induced sensory neuron degeneration are largely unknown. Using a well-established in vitro culture model of dorsal root ganglion (DRG), we have examined degeneration mechanisms triggered on BDNF withdrawal in sensory neurons. Our results indicate differences and similarities between the molecular signaling pathways behind NGF and BDNF deprivation-induced death. For instance, we observed that the inhibition of Trk receptors (K252a), PKC (Gö6976), protein translation (cycloheximide; CHX), or caspases (zVAD-fmk) provides protection from NGF deprivation-induced death but not from degeneration evoked by BDNF-withdrawal. Interestingly, degeneration of BDNF-dependent sensory neurons requires BAX and appears to rely on reactive oxygen species (ROS) generation rather than caspases to induce degeneration. These results highlight the complexity and divergence of mechanisms regulating developmental sensory neuron death.
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11
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Lago-Baldaia I, Fernandes VM, Ackerman SD. More Than Mortar: Glia as Architects of Nervous System Development and Disease. Front Cell Dev Biol 2020; 8:611269. [PMID: 33381506 PMCID: PMC7767919 DOI: 10.3389/fcell.2020.611269] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 11/17/2020] [Indexed: 12/12/2022] Open
Abstract
Glial cells are an essential component of the nervous system of vertebrates and invertebrates. In the human brain, glia are as numerous as neurons, yet the importance of glia to nearly every aspect of nervous system development has only been expounded over the last several decades. Glia are now known to regulate neural specification, synaptogenesis, synapse function, and even broad circuit function. Given their ubiquity, it is not surprising that the contribution of glia to neuronal disease pathogenesis is a growing area of research. In this review, we will summarize the accumulated evidence of glial participation in several distinct phases of nervous system development and organization-neural specification, circuit wiring, and circuit function. Finally, we will highlight how these early developmental roles of glia contribute to nervous system dysfunction in neurodevelopmental and neurodegenerative disorders.
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Affiliation(s)
- Inês Lago-Baldaia
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Vilaiwan M. Fernandes
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Sarah D. Ackerman
- Institute of Neuroscience, Howard Hughes Medical Institute, University of Oregon, Eugene, OR, United States
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12
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Lehotzky D, Sipahi R, Zupanc GKH. Cellular automata modeling suggests symmetric stem-cell division, cell death, and cell drift as key mechanisms driving adult spinal cord growth in teleost fish. J Theor Biol 2020; 509:110474. [PMID: 32918922 DOI: 10.1016/j.jtbi.2020.110474] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 08/10/2020] [Accepted: 08/31/2020] [Indexed: 12/13/2022]
Abstract
Adult neurogenesis - the generation of neurons during adulthood - is intensively studied, yet little is known about its consequences at the tissue level. In the teleost fish Apteronotus leptorhynchus, morphometric analysis has revealed that the total number of cells in the spinal cord increases continuously throughout adulthood, driven by the activity of neurogenic stem/progenitor cells in both the ependymal layer at the central canal and in the radially located parenchyma. This net increase in cell numbers demonstrates cellular addition, as opposed to cellular turnover which appears to be the common outcome of adult neurogenesis in mammals. Grounded on a comprehensive set of quantitative data generated through high-resolution mapping of stem cells and their progeny, we constructed a cellular automata model of the stem-cell-driven growth of the spinal cord. Simulations based on this model suggest that three cellular mechanisms play a critical role for promoting sustained tissue growth and acquisition of correct form of the spinal cord, including the development of the ependymal layer and the parenchyma: the number of symmetric stem-cell divisions versus asymmetric divisions; the probability of the progeny of progenitor cells to undergo cell death; and the radial drifting of cells.
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Affiliation(s)
- Dávid Lehotzky
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA, United States.
| | - Rifat Sipahi
- Complex Dynamic Systems and Control Laboratory, Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, United States.
| | - Günther K H Zupanc
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA, United States.
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13
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Soch A, Sominsky L, Younesi S, De Luca SN, Gunasekara M, Bozinovski S, Spencer SJ. The role of microglia in the second and third postnatal weeks of life in rat hippocampal development and memory. Brain Behav Immun 2020; 88:675-687. [PMID: 32360602 DOI: 10.1016/j.bbi.2020.04.082] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/28/2020] [Accepted: 04/28/2020] [Indexed: 12/31/2022] Open
Abstract
Microglia are resident immune cells of the central nervous system (CNS). In adulthood they are involved in surveillance and responses to pathogens and injury and prenatally they play a role in brain development. However, the role of microglia during the early postnatal period and how they impact development long-term remains poorly understood. Here, to investigate the specific role of microglia in postnatal development, we used a Cx3cr1-Dtr transgenic Wistar rat model to acutely ablate microglia from either postnatal day (P) 7 or 14. We specifically assessed how transient microglial ablation affected astrocytes and neurons acutely, during the juvenile period, and in adulthood. Hippocampal microglial numbers remained low at P21 in the P7-ablated animals and complexity remained reduced after P14-ablation. This protracted effect on these key immune cells led to a small but significant increase in CA1 mature neuron numbers and a significant increase in astrocyte density in the subgranular dentate gyrus in adults that had their microglia ablated at P14. However, these histological differences were small, and spatial and recognition memory in novel objection and place recognition tests were not affected. Overall, our data reveal for the first time that the transient depletion of microglia during the neonatal period impacts briefly on the brain but that the long-lasting effects are minimal. Neonatal microglia may be dispensable in the establishment of hippocampal brain function. These data also imply that novel therapeutic anti-inflammatories that cross the blood-brain barrier to inhibit microglia are unlikely to have long-term negative consequences if administered in the neonatal period.
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Affiliation(s)
- Alita Soch
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic., Australia
| | - Luba Sominsky
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic., Australia
| | - Simin Younesi
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic., Australia
| | - Simone N De Luca
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic., Australia
| | - Maneesha Gunasekara
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic., Australia
| | - Steven Bozinovski
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic., Australia
| | - Sarah J Spencer
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic., Australia; ARC Centre of Excellence for Nanoscale Biophotonics, RMIT University, Melbourne, Vic., Australia.
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14
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Hollville E, Romero SE, Deshmukh M. Apoptotic cell death regulation in neurons. FEBS J 2019; 286:3276-3298. [PMID: 31230407 DOI: 10.1111/febs.14970] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/15/2019] [Accepted: 06/20/2019] [Indexed: 12/16/2022]
Abstract
Apoptosis plays a major role in shaping the developing nervous system during embryogenesis as neuronal precursors differentiate to become post-mitotic neurons. However, once neurons are incorporated into functional circuits and become mature, they greatly restrict their capacity to die via apoptosis, thus allowing the mature nervous system to persist in a healthy and functional state throughout life. This robust restriction of the apoptotic pathway during neuronal differentiation and maturation is defined by multiple unique mechanisms that function to more precisely control and restrict the intrinsic apoptotic pathway. However, while these mechanisms are necessary for neuronal survival, mature neurons are still capable of activating the apoptotic pathway in certain pathological contexts. In this review, we highlight key mechanisms governing the survival of post-mitotic neurons, while also detailing the physiological and pathological contexts in which neurons are capable of overcoming this high apoptotic threshold.
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Affiliation(s)
| | - Selena E Romero
- Neuroscience Center, UNC Chapel Hill, NC, USA.,Department of Cell Biology and Physiology, UNC Chapel Hill, NC, 27599-7250, USA
| | - Mohanish Deshmukh
- Neuroscience Center, UNC Chapel Hill, NC, USA.,Department of Cell Biology and Physiology, UNC Chapel Hill, NC, 27599-7250, USA
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15
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Palacios ER, Isomura T, Parr T, Friston K. The emergence of synchrony in networks of mutually inferring neurons. Sci Rep 2019; 9:6412. [PMID: 31040386 PMCID: PMC6491596 DOI: 10.1038/s41598-019-42821-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 04/08/2019] [Indexed: 01/05/2023] Open
Abstract
This paper considers the emergence of a generalised synchrony in ensembles of coupled self-organising systems, such as neurons. We start from the premise that any self-organising system complies with the free energy principle, in virtue of placing an upper bound on its entropy. Crucially, the free energy principle allows one to interpret biological systems as inferring the state of their environment or external milieu. An emergent property of this inference is synchronisation among an ensemble of systems that infer each other. Here, we investigate the implications of neuronal dynamics by simulating neuronal networks, where each neuron minimises its free energy. We cast the ensuing ensemble dynamics in terms of inference and show that cardinal behaviours of neuronal networks - both in vivo and in vitro - can be explained by this framework. In particular, we test the hypotheses that (i) generalised synchrony is an emergent property of free energy minimisation; thereby explaining synchronisation in the resting brain: (ii) desynchronisation is induced by exogenous input; thereby explaining event-related desynchronisation and (iii) structure learning emerges in response to causal structure in exogenous input; thereby explaining functional segregation in real neuronal systems.
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Affiliation(s)
- Ensor Rafael Palacios
- The Wellcome Centre for Human Neuroimaging, University College London, Queen Square, London, WC1N 3BG, UK.
| | - Takuya Isomura
- Laboratory for Neural Computation and Adaptation, RIKEN Center for Brain Science, Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Thomas Parr
- The Wellcome Centre for Human Neuroimaging, University College London, Queen Square, London, WC1N 3BG, UK
| | - Karl Friston
- The Wellcome Centre for Human Neuroimaging, University College London, Queen Square, London, WC1N 3BG, UK
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16
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Geden MJ, Romero SE, Deshmukh M. Apoptosis versus axon pruning: Molecular intersection of two distinct pathways for axon degeneration. Neurosci Res 2018; 139:3-8. [PMID: 30452947 DOI: 10.1016/j.neures.2018.11.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 11/02/2018] [Accepted: 11/07/2018] [Indexed: 12/16/2022]
Abstract
Neurons are capable of degenerating their axons for the physiological clearance and refinement of unnecessary connections via the programmed degenerative pathways of apoptosis and axon pruning. While both pathways mediate axon degeneration they are however distinct. Whereas in apoptosis the entire neuron, both axons and cell body, degenerates, in the context of axon pruning only the targeted axon segments are selectively degenerated. Interestingly, the molecular pathways mediating axon degeneration in these two contexts have significant mechanistic overlap but also retain distinct differences. In this review, we describe the peripheral neuronal cell culture models used to study the molecular pathways of apoptosis and pruning. We outline what is known about the molecular mechanisms of apoptosis and axon pruning and focus on highlighting the similarities and differences of these two pathways.
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Affiliation(s)
- Matthew J Geden
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, 27599, USA; Neuroscience Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Selena E Romero
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, 27599, USA; Neuroscience Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Mohanish Deshmukh
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, 27599, USA; Neuroscience Center, University of North Carolina, Chapel Hill, NC, 27599, USA.
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17
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Pandey SS, Singh S, Pathak C, Tiwari BS. "Programmed Cell Death: A Process of Death for Survival" - How Far Terminology Pertinent for Cell Death in Unicellular Organisms. J Cell Death 2018; 11:1179066018790259. [PMID: 30116103 PMCID: PMC6088462 DOI: 10.1177/1179066018790259] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 06/22/2018] [Indexed: 02/01/2023] Open
Abstract
Programmed cell death (PCD) is genetically regulated phenomenon of selective elimination of target cells that are either under pathological conditions or unwanted for organism’s normal growth and development due to other reasons. The process although being genetically controlled is physiological in nature that renders some hallmarks like blebs in the cell membrane, lobe formation in nuclear membrane, DNA nicks resulting to DNA ladder of 200 bp, and downstream activation of caspases. Moreover, as the process refers to the death of “targeted cell”, the term is exclusively suitable for multicellular organisms. Number of reports advocate similar type of cell death process in unicellular organisms. As cell death in unicellular organisms is also reflected by the signature of PCD obtained in metazoans, such cell death has been grouped under the broad category of PCD. It is pertinent to mention that by definition a unicellular organism is made of a single cell wherein it carries out all of its life processes. Using the term “Programmed Cell Death” with a preset “survival strategy of the organism” for unicellular organisms looks misnomer. Therefore, this correspondence argues and requests recommendation committee on cell death to revisit for the nomenclature of the cell death process in the unicellular organisms.
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Affiliation(s)
- Shiv Shanker Pandey
- Crop Protection Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Samer Singh
- Department of Microbial Biotechnology, Panjab University, Chandigarh, India
| | - Chandramani Pathak
- Plant Cell Biology & Biotechnology, Institute of Advanced Research (IAR), Gandhinagar, India
| | - Budhi Sagar Tiwari
- Plant Cell Biology & Biotechnology, Institute of Advanced Research (IAR), Gandhinagar, India
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18
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Martín-Ibáñez R, Pardo M, Giralt A, Miguez A, Guardia I, Marion-Poll L, Herranz C, Esgleas M, Garcia-Díaz Barriga G, Edel MJ, Vicario-Abejón C, Alberch J, Girault JA, Chan S, Kastner P, Canals JM. Helios expression coordinates the development of a subset of striatopallidal medium spiny neurons. Development 2017; 144:1566-1577. [PMID: 28289129 PMCID: PMC5399659 DOI: 10.1242/dev.138248] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 03/03/2017] [Indexed: 12/25/2022]
Abstract
Here, we unravel the mechanism of action of the Ikaros family zinc finger protein Helios (He) during the development of striatal medium spiny neurons (MSNs). He regulates the second wave of striatal neurogenesis involved in the generation of striatopallidal neurons, which express dopamine 2 receptor and enkephalin. To exert this effect, He is expressed in neural progenitor cells (NPCs) keeping them in the G1/G0 phase of the cell cycle. Thus, a lack of He results in an increase of S-phase entry and S-phase length of NPCs, which in turn impairs striatal neurogenesis and produces an accumulation of the number of cycling NPCs in the germinal zone (GZ), which end up dying at postnatal stages. Therefore, He−/− mice show a reduction in the number of dorso-medial striatal MSNs in the adult that produces deficits in motor skills acquisition. In addition, overexpression of He in NPCs induces misexpression of DARPP-32 when transplanted in mouse striatum. These findings demonstrate that He is involved in the correct development of a subset of striatopallidal MSNs and reveal new cellular mechanisms for neuronal development. Summary: The transcription factor Helios regulates G1-S transition to promote neuronal differentiation of a striatopallidal neuronal subpopulation involved in motor skill acquisition.
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Affiliation(s)
- Raquel Martín-Ibáñez
- Stem Cells and Regenerative Medicine Laboratory, Production and Validation Center of Advanced Therapies (Creatio), Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain.,Neuroscience Institute, University of Barcelona, 08036 Barcelona, Spain.,August Pi i Sunyer Biomedical Research Institute (IDIBAPS), 08036 Barcelona, Spain.,Networked Biomedical Research Centre for Neurodegenerative Disorders (CIBERNED), Spain.,Research and Development Unit, Production and Validation Center of Advanced Therapies (Creatio), Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain
| | - Mónica Pardo
- Stem Cells and Regenerative Medicine Laboratory, Production and Validation Center of Advanced Therapies (Creatio), Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain.,Neuroscience Institute, University of Barcelona, 08036 Barcelona, Spain.,August Pi i Sunyer Biomedical Research Institute (IDIBAPS), 08036 Barcelona, Spain.,Networked Biomedical Research Centre for Neurodegenerative Disorders (CIBERNED), Spain
| | - Albert Giralt
- August Pi i Sunyer Biomedical Research Institute (IDIBAPS), 08036 Barcelona, Spain.,Networked Biomedical Research Centre for Neurodegenerative Disorders (CIBERNED), Spain.,Pathophysiology of Neurodegenerative Diseases Laboratory, Production and Validation Center of Advanced Therapies (Creatio), Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain
| | - Andrés Miguez
- Stem Cells and Regenerative Medicine Laboratory, Production and Validation Center of Advanced Therapies (Creatio), Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain.,Neuroscience Institute, University of Barcelona, 08036 Barcelona, Spain.,August Pi i Sunyer Biomedical Research Institute (IDIBAPS), 08036 Barcelona, Spain.,Networked Biomedical Research Centre for Neurodegenerative Disorders (CIBERNED), Spain
| | - Inés Guardia
- Stem Cells and Regenerative Medicine Laboratory, Production and Validation Center of Advanced Therapies (Creatio), Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain.,Neuroscience Institute, University of Barcelona, 08036 Barcelona, Spain.,August Pi i Sunyer Biomedical Research Institute (IDIBAPS), 08036 Barcelona, Spain.,Networked Biomedical Research Centre for Neurodegenerative Disorders (CIBERNED), Spain
| | - Lucile Marion-Poll
- Inserm UMR-S839; Université Pierre et Marie Curie (UPMC, Paris 6), Sorbonne Universités; Institut du Fer à Moulin, 75005 Paris, France
| | - Cristina Herranz
- Stem Cells and Regenerative Medicine Laboratory, Production and Validation Center of Advanced Therapies (Creatio), Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain.,Neuroscience Institute, University of Barcelona, 08036 Barcelona, Spain.,August Pi i Sunyer Biomedical Research Institute (IDIBAPS), 08036 Barcelona, Spain.,Networked Biomedical Research Centre for Neurodegenerative Disorders (CIBERNED), Spain.,Research and Development Unit, Production and Validation Center of Advanced Therapies (Creatio), Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain
| | - Miriam Esgleas
- Stem Cells and Regenerative Medicine Laboratory, Production and Validation Center of Advanced Therapies (Creatio), Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain.,August Pi i Sunyer Biomedical Research Institute (IDIBAPS), 08036 Barcelona, Spain.,Networked Biomedical Research Centre for Neurodegenerative Disorders (CIBERNED), Spain
| | - Gerardo Garcia-Díaz Barriga
- Neuroscience Institute, University of Barcelona, 08036 Barcelona, Spain.,August Pi i Sunyer Biomedical Research Institute (IDIBAPS), 08036 Barcelona, Spain.,Networked Biomedical Research Centre for Neurodegenerative Disorders (CIBERNED), Spain.,Pathophysiology of Neurodegenerative Diseases Laboratory, Production and Validation Center of Advanced Therapies (Creatio), Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain
| | - Michael J Edel
- Control of Pluripotency Laboratory, Department of Biomedical Sciences, Faculty of Medicine and Health Science, University of Barcelona, 08036 Barcelona, Spain.,Victor Chang Cardiac Research Institute, Sydney, New South Wales, 2010 Australia.,School of Medicine and Pharmacology, Anatomy, Physiology and Human Biology, CCTRM, University of Western Australia, Western Australia, 6009 Australia
| | - Carlos Vicario-Abejón
- Networked Biomedical Research Centre for Neurodegenerative Disorders (CIBERNED), Spain.,Departamento de Neurobiología Molecular, Celular y del Desarrollo, Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), 28002 Madrid, Spain
| | - Jordi Alberch
- Neuroscience Institute, University of Barcelona, 08036 Barcelona, Spain.,August Pi i Sunyer Biomedical Research Institute (IDIBAPS), 08036 Barcelona, Spain.,Networked Biomedical Research Centre for Neurodegenerative Disorders (CIBERNED), Spain
| | - Jean-Antoine Girault
- Inserm UMR-S839; Université Pierre et Marie Curie (UPMC, Paris 6), Sorbonne Universités; Institut du Fer à Moulin, 75005 Paris, France
| | - Susan Chan
- Stem Cells and Regenerative Medicine Laboratory, Production and Validation Center of Advanced Therapies (Creatio), Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain.,Neuroscience Institute, University of Barcelona, 08036 Barcelona, Spain
| | - Philippe Kastner
- Department of Functional Genomics and Cancer, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Inserm U964, Centre National de la Recherche Scientifique (CNRS) UMR 7104, 67400 Illkirch-Graffenstaden, France.,Faculté de Médecine, Université de Strasbourg, 67081 Strasbourg, France
| | - Josep M Canals
- Stem Cells and Regenerative Medicine Laboratory, Production and Validation Center of Advanced Therapies (Creatio), Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain .,Neuroscience Institute, University of Barcelona, 08036 Barcelona, Spain.,August Pi i Sunyer Biomedical Research Institute (IDIBAPS), 08036 Barcelona, Spain.,Networked Biomedical Research Centre for Neurodegenerative Disorders (CIBERNED), Spain.,Research and Development Unit, Production and Validation Center of Advanced Therapies (Creatio), Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain
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19
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Pfisterer U, Khodosevich K. Neuronal survival in the brain: neuron type-specific mechanisms. Cell Death Dis 2017; 8:e2643. [PMID: 28252642 PMCID: PMC5386560 DOI: 10.1038/cddis.2017.64] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 01/24/2017] [Accepted: 01/31/2017] [Indexed: 12/19/2022]
Abstract
Neurogenic regions of mammalian brain produce many more neurons that will eventually survive and reach a mature stage. Developmental cell death affects both embryonically produced immature neurons and those immature neurons that are generated in regions of adult neurogenesis. Removal of substantial numbers of neurons that are not yet completely integrated into the local circuits helps to ensure that maturation and homeostatic function of neuronal networks in the brain proceed correctly. External signals from brain microenvironment together with intrinsic signaling pathways determine whether a particular neuron will die. To accommodate this signaling, immature neurons in the brain express a number of transmembrane factors as well as intracellular signaling molecules that will regulate the cell survival/death decision, and many of these factors cease being expressed upon neuronal maturation. Furthermore, pro-survival factors and intracellular responses depend on the type of neuron and region of the brain. Thus, in addition to some common neuronal pro-survival signaling, different types of neurons possess a variety of 'neuron type-specific' pro-survival constituents that might help them to adapt for survival in a certain brain region. This review focuses on how immature neurons survive during normal and impaired brain development, both in the embryonic/neonatal brain and in brain regions associated with adult neurogenesis, and emphasizes neuron type-specific mechanisms that help to survive for various types of immature neurons. Importantly, we mainly focus on in vivo data to describe neuronal survival specifically in the brain, without extrapolating data obtained in the PNS or spinal cord, and thus emphasize the influence of the complex brain environment on neuronal survival during development.
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Affiliation(s)
- Ulrich Pfisterer
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - Konstantin Khodosevich
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
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20
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Mosley M, Shah C, Morse KA, Miloro SA, Holmes MM, Ahern TH, Forger NG. Patterns of cell death in the perinatal mouse forebrain. J Comp Neurol 2017; 525:47-64. [PMID: 27199256 PMCID: PMC5116296 DOI: 10.1002/cne.24041] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 12/15/2022]
Abstract
The importance of cell death in brain development has long been appreciated, but many basic questions remain, such as what initiates or terminates the cell death period. One obstacle has been the lack of quantitative data defining exactly when cell death occurs. We recently created a "cell death atlas," using the detection of activated caspase-3 (AC3) to quantify apoptosis in the postnatal mouse ventral forebrain and hypothalamus, and found that the highest rates of cell death were seen at the earliest postnatal ages in most regions. Here we have extended these analyses to prenatal ages and additional brain regions. We quantified cell death in 16 forebrain regions across nine perinatal ages from embryonic day (E) 17 to postnatal day (P) 11 and found that cell death peaks just after birth in most regions. We found greater cell death in several regions in offspring delivered vaginally on the day of parturition compared with those of the same postconception age but still in utero at the time of collection. We also found massive cell death in the oriens layer of the hippocampus on P1 and in regions surrounding the anterior crossing of the corpus callosum on E18 as well as the persistence of large numbers of cells in those regions in adult mice lacking the pro-death Bax gene. Together these findings suggest that birth may be an important trigger of neuronal cell death and identify transient cell groups that may undergo wholesale elimination perinatally. J. Comp. Neurol. 525:47-64, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Morgan Mosley
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, 30302
| | - Charisma Shah
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, 30302
| | - Kiriana A Morse
- Department of Psychology, Center for Behavioral Neuroscience, Quinnipiac University, Hamden, Connecticut, 06518
| | - Stephen A Miloro
- Department of Psychology, Center for Behavioral Neuroscience, Quinnipiac University, Hamden, Connecticut, 06518
| | - Melissa M Holmes
- Department of Psychology, University of Toronto Mississauga, Mississauga, Ontario, L5L 1C6, Canada
| | - Todd H Ahern
- Department of Psychology, Center for Behavioral Neuroscience, Quinnipiac University, Hamden, Connecticut, 06518
| | - Nancy G Forger
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, 30302
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21
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Sharma V, Thakur V, Singh SN, Guleria R. Tumor Necrosis Factor and Alzheimer's Disease: A Cause and Consequence Relationship. ACTA ACUST UNITED AC 2016. [DOI: 10.5455/bcp.20120112064639] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Vivek Sharma
- Government College of Pharmacy, Rohru, Distt. Shimla-171207, Himachal Pradesh, India
| | - Vinay Thakur
- Government College of Pharmacy, Rohru, Distt. Shimla-171207, Himachal Pradesh, India
| | - Shesh Nath Singh
- Government College of Pharmacy, Rohru, Distt. Shimla-171207, Himachal Pradesh, India
| | - Rajender Guleria
- Government College of Pharmacy, Rohru, Distt. Shimla-171207, Himachal Pradesh, India
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22
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Eyo UB, Miner SA, Weiner JA, Dailey ME. Developmental changes in microglial mobilization are independent of apoptosis in the neonatal mouse hippocampus. Brain Behav Immun 2016; 55:49-59. [PMID: 26576723 PMCID: PMC4864211 DOI: 10.1016/j.bbi.2015.11.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 10/09/2015] [Accepted: 11/09/2015] [Indexed: 12/31/2022] Open
Abstract
During CNS development, microglia transform from highly mobile amoeboid-like cells to primitive ramified forms and, finally, to highly branched but relatively stationary cells in maturity. The factors that control developmental changes in microglia are largely unknown. Because microglia detect and clear apoptotic cells, developmental changes in microglia may be controlled by neuronal apoptosis. Here, we assessed the extent to which microglial cell density, morphology, motility, and migration are regulated by developmental apoptosis, focusing on the first postnatal week in the mouse hippocampus when the density of apoptotic bodies peaks at postnatal day 4 and declines sharply thereafter. Analysis of microglial form and distribution in situ over the first postnatal week showed that, although there was little change in the number of primary microglial branches, microglial cell density increased significantly, and microglia were often seen near or engulfing apoptotic bodies. Time-lapse imaging in hippocampal slices harvested at different times over the first postnatal week showed differences in microglial motility and migration that correlated with the density of apoptotic bodies. The extent to which these changes in microglia are driven by developmental neuronal apoptosis was assessed in tissues from BAX null mice lacking apoptosis. We found that apoptosis can lead to local microglial accumulation near apoptotic neurons in the pyramidal cell body layer but, unexpectedly, loss of apoptosis did not alter overall microglial cell density in vivo or microglial motility and migration in ex vivo tissue slices. These results demonstrate that developmental changes in microglial form, distribution, motility, and migration occur essentially normally in the absence of developmental apoptosis, indicating that factors other than neuronal apoptosis regulate these features of microglial development.
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23
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Tung YT, Lu YL, Peng KC, Yen YP, Chang M, Li J, Jung H, Thams S, Huang YP, Hung JH, Chen JA. Mir-17∼92 Governs Motor Neuron Subtype Survival by Mediating Nuclear PTEN. Cell Rep 2016; 11:1305-18. [PMID: 26004179 DOI: 10.1016/j.celrep.2015.04.050] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 03/17/2015] [Accepted: 04/22/2015] [Indexed: 01/07/2023] Open
Abstract
Motor neurons (MNs) are unique because they project their axons outside of the CNS to innervate the peripheral muscles. Limb-innervating lateral motor column MNs (LMC-MNs) travel substantially to innervate distal limb mesenchyme. How LMC-MNs fine-tune the balance between survival and apoptosis while wiring the sensorimotor circuit en route remains unclear. Here, we show that the mir-17∼92 cluster is enriched in embryonic stem cell (ESC)-derived LMC-MNs and that conditional mir-17∼92 deletion in MNs results in the death of LMC-MNs in vitro and in vivo. mir-17∼92 overexpression rescues MNs from apoptosis, which occurs spontaneously during embryonic development. PTEN is a primary target of mir-17∼92 responsible for LMC-MN degeneration. Additionally, mir-17∼92 directly targets components of E3 ubiquitin ligases, affecting PTEN subcellular localization through monoubiquitination. This miRNA-mediated regulation modulates both target expression and target subcellular localization, providing LMC-MNs with an intricate defensive mechanism that controls their survival.
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24
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Lovelace MD, Gu BJ, Eamegdool SS, Weible MW, Wiley JS, Allen DG, Chan-Ling T. P2X7 receptors mediate innate phagocytosis by human neural precursor cells and neuroblasts. Stem Cells 2015; 33:526-41. [PMID: 25336287 DOI: 10.1002/stem.1864] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 09/10/2014] [Accepted: 09/29/2014] [Indexed: 12/22/2022]
Abstract
During early human neurogenesis there is overproduction of neuroblasts and neurons accompanied by widespread programmed cell death (PCD). While it is understood that CD68(+) microglia and astrocytes mediate phagocytosis during target-dependent PCD, little is known of the cell identity or the scavenger molecules used to remove apoptotic corpses during the earliest stages of human neurogenesis. Using a combination of multiple-marker immunohistochemical staining, functional blocking antibodies and antagonists, we showed that human neural precursor cells (hNPCs) and neuroblasts express functional P2X7 receptors. Furthermore, using live-cell imaging, flow cytometry, phagocytic assays, and siRNA knockdown, we showed that in a serum-free environment, doublecortin(+) (DCX) neuroblasts and hNPCs can clear apoptotic cells by innate phagocytosis mediated via P2X7. We found that both P2X7(high) DCX(low) hNPCs and P2X7(high) DCX(high) neuroblasts, derived from primary cultures of human fetal telencephalon, phagocytosed targets including latex beads, apoptotic ReNcells, and apoptotic hNPC/neuroblasts. Pretreatment of neuroblasts and hNPCs with 1 mM adenosine triphosphate (ATP), 100 µM OxATP (P2X7 antagonist), or siRNA knockdown of P2X7 inhibited phagocytosis of these targets. Our results show that P2X7 functions as a scavenger receptor under serum-free conditions resembling those in early neurogenesis. This is the first demonstration that hNPCs and neuroblasts may participate in clearance of apoptotic corpses during pre target-dependent neurogenesis and mediate phagocytosis using P2X7 as a scavenger receptor.
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Affiliation(s)
- Michael D Lovelace
- Discipline of Anatomy and Histology, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia; Bosch Institute, The University of Sydney, Sydney, New South Wales, Australia
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25
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Tower J. Programmed cell death in aging. Ageing Res Rev 2015; 23:90-100. [PMID: 25862945 DOI: 10.1016/j.arr.2015.04.002] [Citation(s) in RCA: 247] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 03/15/2015] [Accepted: 04/01/2015] [Indexed: 02/08/2023]
Abstract
Programmed cell death (PCD) pathways, including apoptosis and regulated necrosis, are required for normal cell turnover and tissue homeostasis. Mis-regulation of PCD is increasingly implicated in aging and aging-related disease. During aging the cell turnover rate declines for several highly-mitotic tissues. Aging-associated disruptions in systemic and inter-cell signaling combined with cell-autonomous damage and mitochondrial malfunction result in increased PCD in some cell types, and decreased PCD in other cell types. Increased PCD during aging is implicated in immune system decline, skeletal muscle wasting (sarcopenia), loss of cells in the heart, and neurodegenerative disease. In contrast, cancer cells and senescent cells are resistant to PCD, enabling them to increase in abundance during aging. PCD pathways limit life span in fungi, but whether PCD pathways normally limit adult metazoan life span is not yet clear. PCD is regulated by a balance of negative and positive factors, including the mitochondria, which are particularly subject to aging-associated malfunction.
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26
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Takikita S, Takano T, Narita T, Maruo Y. Increased apoptosis and hypomyelination in cerebral white matter of macular mutant mouse brain. Mol Genet Metab Rep 2015; 4:25-9. [PMID: 26937406 PMCID: PMC4750634 DOI: 10.1016/j.ymgmr.2015.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 05/25/2015] [Indexed: 12/18/2022] Open
Abstract
Hypomyelination in developing brain is often accompanied by congenital metabolic disorders. Menkes kinky hair disease is an X-linked neurodegenerative disease of impaired copper transport, resulting from a mutation of the Menkes disease gene, a transmembrane copper-transporting p-type ATPase gene (ATP7A). In a macular mutant mouse model, the murine ortholog of Menkes gene (mottled gene) is mutated, and widespread neurodegeneration and subsequent death are observed. Although some biochemical analysis of myelin protein in macular mouse has been reported, detailed histological study of myelination in this mouse model is currently lacking. Since myelin abnormality is one of the neuropathologic findings of human Menkes disease, in this study early myelination in macular mouse brain was evaluated by immunohistochemistry. Two-week-old macular mice and normal littermates were perfused with 4% paraformaldehyde. Immunohistochemical staining of paraffin embedded and vibratome sections was performed using antibodies against either CNPase, cleaved caspase-3 or O4 (marker of immature oligodendrocytes). This staining showed that cerebral myelination in macular mouse was generally hypoplastic and that hypomyelination was remarkable in internal capsule, corpus callosum, and cingulate cortex. In addition, an increased number of cleaved caspase-3 positive cells were observed in corpus callosum and internal capsule. Copper deficiency induced by low copper diet has been reported to induce oligodendrocyte dysfunction and leads to hypomyelination in this mouse model. Taken together, hypomyelination observed in this study in a mouse model of Menkes disease is assumed to be induced by increased apoptosis of immature oligodendrocytes in developing cerebrum, through deficient intracellular copper metabolism.
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Affiliation(s)
- Shoichi Takikita
- Department of Pediatrics, Takatsuki Red Cross Hospital, Takatsuki 569-1096, Japan
| | - Tomoyuki Takano
- Department of Pediatrics, Shiga University of Medical Science, Otsu 520-2192, Japan
| | - Tsutomu Narita
- Department of Pediatrics, Takatsuki Red Cross Hospital, Takatsuki 569-1096, Japan
| | - Yoshihiro Maruo
- Department of Pediatrics, Shiga University of Medical Science, Otsu 520-2192, Japan
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Cell biology of the NCL proteins: What they do and don't do. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2242-55. [PMID: 25962910 DOI: 10.1016/j.bbadis.2015.04.027] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 04/23/2015] [Accepted: 04/24/2015] [Indexed: 02/06/2023]
Abstract
The fatal, primarily childhood neurodegenerative disorders, neuronal ceroid lipofuscinoses (NCLs), are currently associated with mutations in 13 genes. The protein products of these genes (CLN1 to CLN14) differ in their function and their intracellular localization. NCL-associated proteins have been localized mostly in lysosomes (CLN1, CLN2, CLN3, CLN5, CLN7, CLN10, CLN12 and CLN13) but also in the Endoplasmic Reticulum (CLN6 and CLN8), or in the cytosol associated to vesicular membranes (CLN4 and CLN14). Some of them such as CLN1 (palmitoyl protein thioesterase 1), CLN2 (tripeptidyl-peptidase 1), CLN5, CLN10 (cathepsin D), and CLN13 (cathepsin F), are lysosomal soluble proteins; others like CLN3, CLN7, and CLN12, have been proposed to be lysosomal transmembrane proteins. In this review, we give our views and attempt to summarize the proposed and confirmed functions of each NCL protein and describe and discuss research results published since the last review on NCL proteins. This article is part of a Special Issue entitled: "Current Research on the Neuronal Ceroid Lipofuscinoses (Batten Disease)".
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Dietrich AK, Humphreys GI, Nardulli AM. Expression of estrogen receptor α in the mouse cerebral cortex. Mol Cell Endocrinol 2015; 406:19-26. [PMID: 25700604 PMCID: PMC4773199 DOI: 10.1016/j.mce.2015.02.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 02/11/2015] [Accepted: 02/12/2015] [Indexed: 12/15/2022]
Abstract
Although estrogen receptor alpha (ERα) and 17β-estradiol play critical roles in protecting the cerebral cortex from ischemia-induced damage, there has been some controversy about the expression of ERα in this region of the brain. We have examined ERα mRNA and protein levels in the cerebral cortices of female mice at postnatal days 5 and 17 and at 4, 13, and 18 months of age. We found that although ERα transcript levels declined from postnatal day 5 through 18 months of age, ERα protein levels remained stable. Importantly, expression of the E2-regulated progesterone receptor gene was sustained in younger and in older females suggesting that age-related changes in estrogen responsiveness in the cerebral cortex are not due to the absence of ERα protein.
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Affiliation(s)
- Alicia K Dietrich
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Gwendolyn I Humphreys
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Ann M Nardulli
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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Sensory deprivation disrupts homeostatic regeneration of newly generated olfactory sensory neurons after injury in adult mice. J Neurosci 2015; 35:2657-73. [PMID: 25673857 DOI: 10.1523/jneurosci.2484-14.2015] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Although it is well known that injury induces the generation of a substantial number of new olfactory sensory neurons (OSNs) in the adult olfactory epithelium (OE), it is not well understood whether olfactory sensory input influences the survival and maturation of these injury-induced OSNs in adults. Here, we investigated whether olfactory sensory deprivation affected the dynamic incorporation of newly generated OSNs 3, 7, 14, and 28 d after injury in adult mice. Mice were unilaterally deprived of olfactory sensory input by inserting a silicone tube into their nostrils. Methimazole, an olfactotoxic drug, was also injected intraperitoneally to bilaterally ablate OSNs. The OE was restored to its preinjury condition with new OSNs by day 28. No significant differences in the numbers of olfactory marker protein-positive mature OSNs or apoptotic OSNs were observed between the deprived and nondeprived sides 0-7 d after injury. However, between days 7 and 28, the sensory-deprived side showed markedly fewer OSNs and mature OSNs, but more apoptotic OSNs, than the nondeprived side. Intrinsic functional imaging of the dorsal surface of the olfactory bulb at day 28 revealed that responses to odor stimulation were weaker in the deprived side compared with those in the nondeprived side. Furthermore, prevention of cell death in new neurons 7-14 d after injury promoted the recovery of the OE. These results indicate that, in the adult OE, sensory deprivation disrupts compensatory OSN regeneration after injury and that newly generated OSNs have a critical time window for sensory-input-dependent survival 7-14 d after injury.
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Orr ME, Garbarino VR, Salinas A, Buffenstein R. Sustained high levels of neuroprotective, high molecular weight, phosphorylated tau in the longest-lived rodent. Neurobiol Aging 2015; 36:1496-504. [PMID: 25576082 PMCID: PMC4869521 DOI: 10.1016/j.neurobiolaging.2014.12.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 11/24/2014] [Accepted: 12/04/2014] [Indexed: 12/27/2022]
Abstract
Tau protein is primarily expressed in neuronal axons and modulates microtubule stability. Tau phosphorylation, aggregation, and subcellular mislocalization coincide with neurodegeneration in numerous diseases, including Alzheimer's disease (AD). During AD pathogenesis, tau misprocessing accompanies Aß accumulation; however, AD animal models, despite elevated Aß, fail to develop tauopathy. To assess whether lack of tau pathology is linked to short life span common to most AD models, we examined tau processing in extraordinarily long-lived, mouse-sized naked mole-rats (NMRs; approximately 32 years), which express appreciable levels of Aß throughout life. We found that NMRs, like other mammals, display highest tau phosphorylation during brain development. Although tau phosphorylation decreases with aging, unexpectedly adult NMRs have higher levels than transgenic mice overexpressing mutant human tau. However, in sharp contrast with the somatodendritic accumulation of misprocessed tau in the transgenic mice, NMRs maintain axonal tau localization. Intriguingly, the adult NMR tau protein is 88 kDa, much larger than 45-68 kDa tau expressed in other mammals. We propose that this 88 kDa tau protein may offer exceptional microtubule stability and neuroprotection against lifelong, elevated Aß.
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Affiliation(s)
- Miranda E Orr
- Department of Physiology and The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Valentina R Garbarino
- Department of Physiology and The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Angelica Salinas
- Department of Physiology and The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Rochelle Buffenstein
- Department of Physiology and The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
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Padmanabhan J, Brown KR, Padilla A, Shelanski ML. Functional role of RNA polymerase II and P70 S6 kinase in KCl withdrawal-induced cerebellar granule neuron apoptosis. J Biol Chem 2015; 290:5267-79. [PMID: 25568312 DOI: 10.1074/jbc.m114.575225] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
KCl withdrawal-induced apoptosis in cerebellar granule neurons is associated with aberrant cell cycle activation, and treatment with cyclin-dependent kinase (Cdk) inhibitors protects cells from undergoing apoptosis. Because the Cdk inhibitor flavopiridol is known to inhibit RNA polymerase II (Pol II)-dependent transcription elongation by inhibiting the positive transcription elongation factor b (P-TEFb, a complex of CDK9 and cyclin T), we examined whether inhibition of RNA Pol II protects neurons from apoptosis. Treatment of neurons with 5, 6-dichloro-1-β-D-ribobenzimidazole (DRB), an RNA Pol II-dependent transcription elongation inhibitor, and flavopiridol inhibited phosphorylation and activation of Pol II and protected neurons from undergoing apoptosis. In addition to Pol II, neurons subjected to KCl withdrawal showed increased phosphorylation and activation of p70 S6 kinase, which was inhibited by both DRB and flavopiridol. Immunostaining analysis of the neurons deprived of KCl showed increased nuclear levels of phospho-p70 S6 kinase, and neurons protected with DRB and flavopiridol showed accumulation of the kinase into large spliceosome assembly factor-positive speckle domains within the nuclei. The formation of these foci corresponded with cell survival, and removal of the inhibitors resulted in dispersal of the speckles into smaller foci with subsequent apoptosis induction. Because p70 S6 kinase is known to induce translation of mRNAs containing a 5'-terminal oligopyrimidine tract, our data suggest that transcription and translation of this subset of mRNAs may contribute to KCl withdrawal-induced apoptosis in neurons.
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Affiliation(s)
- Jaya Padmanabhan
- From the Department of Molecular Medicine, University of South Florida Health Byrd Alzheimer's Institute, University of South Florida, Tampa, Florida 33613 and
| | - Kristy R Brown
- the Department of Pathology and Cell Biology, Taub Center for Alzheimer's Disease, College of Physicians and Surgeons, Columbia University, New York, New York 10032
| | - Amelia Padilla
- From the Department of Molecular Medicine, University of South Florida Health Byrd Alzheimer's Institute, University of South Florida, Tampa, Florida 33613 and
| | - Michael L Shelanski
- the Department of Pathology and Cell Biology, Taub Center for Alzheimer's Disease, College of Physicians and Surgeons, Columbia University, New York, New York 10032
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Modeling local and cross-species neuron number variations in the cerebral cortex as arising from a common mechanism. Proc Natl Acad Sci U S A 2014; 111:17642-7. [PMID: 25422426 DOI: 10.1073/pnas.1409271111] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A massive increase in the number of neurons in the cerebral cortex, driving its size to increase by five orders of magnitude, is a key feature of mammalian evolution. Not only are there systematic variations in cerebral cortical architecture across species, but also across spatial axes within a given cortex. In this article we present a computational model that accounts for both types of variation as arising from the same developmental mechanism. The model employs empirically measured parameters from over a dozen species to demonstrate that changes to the kinetics of neurogenesis (the cell-cycle rate, the progenitor death rate, and the "quit rate," i.e., the ratio of terminal cell divisions) are sufficient to explain the great diversity in the number of cortical neurons across mammals. Moreover, spatiotemporal gradients in those same parameters in the embryonic cortex can account for cortex-wide, graded variations in the mature neural architecture. Consistent with emerging anatomical data in several species, the model predicts (i) a greater complement of neurons per cortical column in the later-developing, posterior regions of intermediate and large cortices, (ii) that the extent of variation across a cortex increases with cortex size, reaching fivefold or greater in primates, and (iii) that when the number of neurons per cortical column increases, whether across species or within a given cortex, it is the later-developing superficial layers of the cortex which accommodate those additional neurons. We posit that these graded features of the cortex have computational and functional significance, and so must be subject to evolutionary selection.
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Lewitus E, Kelava I, Kalinka AT, Tomancak P, Huttner WB. An adaptive threshold in mammalian neocortical evolution. PLoS Biol 2014; 12:e1002000. [PMID: 25405475 PMCID: PMC4236020 DOI: 10.1371/journal.pbio.1002000] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 10/09/2014] [Indexed: 01/19/2023] Open
Abstract
A study of the evolutionary history of cortical folding in mammals, its relationship to physiological and life-history traits and the underlying cortical progenitor behavior during embryogenesis, explains the diversity of folding we see across modern mammals. The diversity of neocortical folding among mammals can be explained by two distinct neurogenic programs, which give rise to mammals with a highly folded neocortex and mammals with slightly folded or unfolded neocortex, each occupying a distinct ecological niche. Expansion of the neocortex is a hallmark of human evolution. However, determining which adaptive mechanisms facilitated its expansion remains an open question. Here we show, using the gyrencephaly index (GI) and other physiological and life-history data for 102 mammalian species, that gyrencephaly is an ancestral mammalian trait. We find that variation in GI does not evolve linearly across species, but that mammals constitute two principal groups above and below a GI threshold value of 1.5, approximately equal to 109 neurons, which may be characterized by distinct constellations of physiological and life-history traits. By integrating data on neurogenic period, neuroepithelial founder pool size, cell-cycle length, progenitor-type abundances, and cortical neuron number into discrete mathematical models, we identify symmetric proliferative divisions of basal progenitors in the subventricular zone of the developing neocortex as evolutionarily necessary for generating a 14-fold increase in daily prenatal neuron production, traversal of the GI threshold, and thus establishment of two principal groups. We conclude that, despite considerable neuroanatomical differences, changes in the length of the neurogenic period alone, rather than any novel neurogenic progenitor lineage, are sufficient to explain differences in neuron number and neocortical size between species within the same principal group. What are the key differences in the development and evolution of the cerebral cortex that underlie the differences in its size and degree of folding across mammals? Here, we present phylogenetic evidence that the Jurassic era mammalian ancestor may have been a relatively large-brained species with a folded neocortex. We then show that variation in the degree of cortical folding (gyrencephaly index [GI]) does not evolve linearly across species, as previously assumed, but that mammals fall into two principal groups associated with distinct ecological niches: low-GI mammals (such as mice and tarsiers) and high-GI mammals (such as dolphins and humans), which are found to generate on average 14-fold more brain weight per day of gestation. This greater daily brain weight production in mammals with a highly folded neocortex requires a specific class of progenitor cell-type to adopt a special mode of cell division, which is absent in mammals with slightly folded or unfolded neocortices. Differences among mammals within the same GI group (high or low) are not due to different programming, but rather the result of differences in the length of the neurogenic period. So, the impressively large and folded human neocortex, which is three times the size of the chimpanzee neocortex, can be explained by a modest evolutionary extension of the neurogenic period with respect to its closest primate ancestors.
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Affiliation(s)
- Eric Lewitus
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- * E-mail: (EL); (WBH)
| | - Iva Kelava
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Alex T. Kalinka
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Pavel Tomancak
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Wieland B. Huttner
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- * E-mail: (EL); (WBH)
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Abstract
Neuronal cell death happens as a result of the normal physiological process that occurs during development, or as part of the pathological process that occurs during disease. Death-associated protein kinase (DAPK) is an intracellular protein that mediates cell death by its serine/threonine kinase activity, and transmits apoptotic cell death signals in various cells, including neurons. DAPK is elevated in injured neurons in acute models of injury such as ischemia and seizure. The absence of DAPK has been shown to protect neurons from a wide variety of acute toxic insults. Moreover, DAPK also regulates neuronal cell death during central nervous system development. Neurons are initially overproduced in the developing nervous system, following which approximately one-half of the original cell population dies. This "naturally-occurring" or "programmed" cell death is essential for the construction of the developing nervous system. In this review, we focus on the role of DAPK in neuronal cell death after neuronal injury. The participation of DAPK in developmental neuronal death is also explained.
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Affiliation(s)
- Yuki Fujita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan
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35
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Sullivan CS, Scheib JL, Ma Z, Dang RP, Schafer JM, Hickman FE, Brodsky FM, Ravichandran KS, Carter BD. The adaptor protein GULP promotes Jedi-1-mediated phagocytosis through a clathrin-dependent mechanism. Mol Biol Cell 2014; 25:1925-36. [PMID: 24743597 PMCID: PMC4055271 DOI: 10.1091/mbc.e13-11-0658] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
During the development of the peripheral nervous system, the large number of apoptotic neurons generated are phagocytosed by glial precursor cells. This clearance is mediated, in part, through the mammalian engulfment receptor Jedi-1. However, the mechanisms by which Jedi-1 mediates phagocytosis are poorly understood. Here we demonstrate that Jedi-1 associates with GULP, the mammalian homologue of CED-6, an adaptor protein required for phagocytosis mediated by the nematode engulfment receptor CED-1. Silencing GULP or mutating the NPXY motif in Jedi-1, which is required for GULP binding, prevents Jedi-1-mediated phagocytosis. How GULP promotes engulfment is not known. Of interest, we find that Jedi-1-induced phagocytosis requires GULP binding to clathrin heavy chain (CHC). During engulfment, CHC is tyrosine phosphorylated, which is required for Jedi-mediated engulfment. Both phosphoclathrin and actin accumulate around engulfed microspheres. Furthermore, knockdown of CHC in HeLa cells prevents Jedi-1-mediated engulfment of microspheres, and knockdown in glial precursors prevents the engulfment of apoptotic neurons. Taken together, these results reveal that Jedi-1 signals through recruitment of GULP, which promotes phagocytosis through a noncanonical phosphoclathrin-dependent mechanism.
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Affiliation(s)
- Chelsea S Sullivan
- Department of Biochemistry, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Jami L Scheib
- Department of Biochemistry, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Zhong Ma
- Center for Cell Clearance and Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Rajan P Dang
- Department of Biochemistry, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Johanna M Schafer
- Department of Biochemistry, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Francis E Hickman
- Department of Biochemistry, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Frances M Brodsky
- Department of Bioengineering and Therapeutic Sciences, Department of Microbiology and Immunology, and Department of Pharmaceutical Chemistry, G. W. Hooper Foundation, University of California, San Francisco, San Francisco, CA 94143
| | - Kodi S Ravichandran
- Center for Cell Clearance and Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Bruce D Carter
- Department of Biochemistry, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232
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36
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Drosos Y, Kouloukoussa M, Ostvold AC, Havaki S, Katsantoni E, Marinos E, Aleporou-Marinou V. Dynamic expression of the vertebrate-specific protein Nucks during rodent embryonic development. Gene Expr Patterns 2013; 14:19-29. [PMID: 24140890 DOI: 10.1016/j.gep.2013.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 09/23/2013] [Accepted: 10/07/2013] [Indexed: 11/15/2022]
Abstract
The nuclear casein kinase and cyclin-dependent kinase substrate 1 (NUCKS) is a highly phosphorylated nuclear protein that is overexpressed in many types of cancer. The flexibility of NUCKS and its extensive posttranslational modifications indicate that it is multifunctional, and its expression in most cell types suggests a housekeeping function. However, spatiotemporal expression of the Nucks protein during rodent development has not been reported. Thus, we investigated the expression of both the Nucks mRNA and protein during rat and mouse development by immunohistochemistry, in situ hybridization, Western immunoblotting, and reverse-transcription PCR analysis. We also used BLAST analysis against expressed sequence tag databases to determine whether a NUCKS homologue is expressed in invertebrate organisms. We found that Nucks expression increased during the initial stages of embryonic development, and then gradually decreased until birth in all tissues except the nervous tissue and muscle fibers. Interestingly, the expression of Nucks was very strong in migrating neural crest cells at E13.5 and ectoderm-derived tissues. In most tissues analyzed, the levels of Nucks correlated with the levels of Bax and activated caspase-3, which are indicative of apoptosis. Moreover, Nucks was upregulated very early during neuronal apoptosis in vitro. Expression analysis revealed that no transcript with close homology to the Nucks gene was present in invertebrates. The expression of Nucks in both proliferating and quiescent cells and its correlation with Bax levels and apoptosis strongly suggest that Nucks plays complex roles in cell homeostasis. Furthermore, the lack of homology in invertebrate organisms indicates a specific role for Nucks in vertebrate embryogenesis.
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Affiliation(s)
- Yiannis Drosos
- Department of Genetics and Biotechnology, Faculty of Biology, University of Athens, Panepistimioupoli, 15701 Ilissia, Greece.
| | - Mirsini Kouloukoussa
- Laboratory of Histology and Embryology, Medical School, University of Athens, 75 Mikras Asias Str., 11527 Goudi, Greece
| | - Anne Carine Ostvold
- Department of Biochemistry, Institute of Basic Medical Sciences, University of Oslo, PO Box 1112, Blindern, 0317 Oslo, Norway
| | - Sophia Havaki
- Laboratory of Histology and Embryology, Medical School, University of Athens, 75 Mikras Asias Str., 11527 Goudi, Greece
| | - Eleni Katsantoni
- Hematology/Oncology Division, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece
| | - Evangelos Marinos
- Laboratory of Histology and Embryology, Medical School, University of Athens, 75 Mikras Asias Str., 11527 Goudi, Greece
| | - Vassiliki Aleporou-Marinou
- Department of Genetics and Biotechnology, Faculty of Biology, University of Athens, Panepistimioupoli, 15701 Ilissia, Greece
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Lake JI, Heuckeroth RO. Enteric nervous system development: migration, differentiation, and disease. Am J Physiol Gastrointest Liver Physiol 2013; 305:G1-24. [PMID: 23639815 PMCID: PMC3725693 DOI: 10.1152/ajpgi.00452.2012] [Citation(s) in RCA: 229] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The enteric nervous system (ENS) provides the intrinsic innervation of the bowel and is the most neurochemically diverse branch of the peripheral nervous system, consisting of two layers of ganglia and fibers encircling the gastrointestinal tract. The ENS is vital for life and is capable of autonomous regulation of motility and secretion. Developmental studies in model organisms and genetic studies of the most common congenital disease of the ENS, Hirschsprung disease, have provided a detailed understanding of ENS development. The ENS originates in the neural crest, mostly from the vagal levels of the neuraxis, which invades, proliferates, and migrates within the intestinal wall until the entire bowel is colonized with enteric neural crest-derived cells (ENCDCs). After initial migration, the ENS develops further by responding to guidance factors and morphogens that pattern the bowel concentrically, differentiating into glia and neuronal subtypes and wiring together to form a functional nervous system. Molecules controlling this process, including glial cell line-derived neurotrophic factor and its receptor RET, endothelin (ET)-3 and its receptor endothelin receptor type B, and transcription factors such as SOX10 and PHOX2B, are required for ENS development in humans. Important areas of active investigation include mechanisms that guide ENCDC migration, the role and signals downstream of endothelin receptor type B, and control of differentiation, neurochemical coding, and axonal targeting. Recent work also focuses on disease treatment by exploring the natural role of ENS stem cells and investigating potential therapeutic uses. Disease prevention may also be possible by modifying the fetal microenvironment to reduce the penetrance of Hirschsprung disease-causing mutations.
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Affiliation(s)
- Jonathan I. Lake
- 1Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri; and
| | - Robert O. Heuckeroth
- 1Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri; and ,2Department of Developmental, Regenerative, and Stem Cell Biology, Washington University School of Medicine, St. Louis, Missouri
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Buckley DM, Burroughs-Garcia J, Lewandoski M, Waters ST. Characterization of the Gbx1-/- mouse mutant: a requirement for Gbx1 in normal locomotion and sensorimotor circuit development. PLoS One 2013; 8:e56214. [PMID: 23418536 PMCID: PMC3572027 DOI: 10.1371/journal.pone.0056214] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 01/08/2013] [Indexed: 01/13/2023] Open
Abstract
The Gbx class of homeobox genes encodes DNA binding transcription factors involved in regulation of embryonic central nervous system (CNS) development. Gbx1 is dynamically expressed within spinal neuron progenitor pools and becomes restricted to the dorsal mantle zone by embryonic day (E) 12.5. Here, we provide the first functional analysis of Gbx1. We generated mice containing a conditional Gbx1 allele in which exon 2 that contains the functional homeodomain is flanked with loxP sites (Gbx1(flox)); Cre-mediated recombination of this allele results in a Gbx1 null allele. In contrast to mice homozygous for a loss-of-function allele of Gbx2, mice homozygous for the Gbx1 null allele, Gbx1(-/-), are viable and reproductively competent. However, Gbx1(-/-) mice display a gross locomotive defect that specifically affects hindlimb gait. Analysis of embryos homozygous for the Gbx1 null allele reveals disrupted assembly of the proprioceptive sensorimotor circuit within the spinal cord, and a reduction in ISL1(+) ventral motor neurons. These data suggest a functional requirement for Gbx1 in normal development of the neural networks that contribute to locomotion. The generation of this null allele has enabled us to functionally characterize a novel role for Gbx1 in development of the spinal cord.
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Affiliation(s)
- Desirè M. Buckley
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States of America
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
| | - Jessica Burroughs-Garcia
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States of America
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
| | - Mark Lewandoski
- Cancer and Developmental Biology Laboratory, National Cancer Institute, National Institutes of Health, Frederick, Maryland, United States of America
| | - Samuel T. Waters
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States of America
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
- * E-mail:
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39
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Eyo UB, Dailey ME. Microglia: key elements in neural development, plasticity, and pathology. J Neuroimmune Pharmacol 2013; 8:494-509. [PMID: 23354784 DOI: 10.1007/s11481-013-9434-z] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Accepted: 01/14/2013] [Indexed: 12/31/2022]
Abstract
A century after Cajal identified a "third element" of the nervous system, many issues have been clarified about the identity and function of one of its major components, the microglia. Here, we review recent findings by microgliologists, highlighting results from imaging studies that are helping provide new views of microglial behavior and function. In vivo imaging in the intact adult rodent CNS has revolutionized our understanding of microglial behaviors in situ and has raised speculation about their function in the uninjured adult brain. Imaging studies in ex vivo mammalian tissue preparations and in intact model organisms including zebrafish are providing insights into microglial behaviors during brain development. These data suggest that microglia play important developmental roles in synapse remodeling, developmental apoptosis, phagocytic clearance, and angiogenesis. Because microglia also contribute to pathology, including neurodevelopmental and neurobehavioral disorders, ischemic injury, and neuropathic pain, promising new results raise the possibility of leveraging microglia for therapeutic roles. Finally, exciting recent work is addressing unanswered questions regarding the nature of microglial-neuronal communication. While it is now apparent that microglia play diverse roles in neural development, behavior, and pathology, future research using neuroimaging techniques will be essential to more fully exploit these intriguing cellular targets for effective therapeutic intervention applied to a variety of conditions.
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Affiliation(s)
- Ukpong B Eyo
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
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40
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Zhao Y, Xiao J, Gong S, Clara JA, Ledoux MS. Neural expression of the transcription factor THAP1 during development in rat. Neuroscience 2012; 231:282-95. [PMID: 23219941 DOI: 10.1016/j.neuroscience.2012.11.049] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 11/24/2012] [Accepted: 11/27/2012] [Indexed: 10/27/2022]
Abstract
Loss of function mutations in THAP1 has been associated with primary generalized and focal dystonia in children and adults. THAP1 encodes a transcription factor (THAP1) that harbors an atypical zinc finger domain and plays a critical role in G(1)-S cell cycle control. Current thinking suggests that dystonia may be a neurodevelopmental circuit disorder. Hence, THAP1 may participate in the development of the nervous system. Herein, we report the neurodevelopmental expression patterns of Thap1 transcript and THAP1 protein from the early postnatal period through adulthood in the rat brain, spinal cord and dorsal root ganglia (DRG). We detected Thap1 transcript and THAP1-immunoreactivity (IR) in the cerebral cortex, cerebellum, striatum, substantia nigra, thalamus, spinal cord and DRG. Thap1 transcript expression was higher in the brain than in spinal cord and DRG at P1 and P7 and declined to similar levels at P14 and later time points in all regions except the cerebellum, where it remained high through adulthood. In the brain, THAP1 expression was highest in early development, particularly in the cerebellum at P7. In addition to Purkinje cells in the cerebellum, THAP1-IR was also localized to pyramidal neurons in the cerebral cortex, relay neurons in the thalamus, medium spiny and cholinergic neurons in the striatum, dopaminergic neurons in the substantia nigra, and pyramidal and interneurons in the hippocampus. In the cerebellar cortex, THAP1-IR was prominently distributed in the perikarya and proximal dendrites of Purkinje cells at early time-points. In contrast, it was more diffusely distributed throughout the dendritic arbor of adult Purkinje cells producing a moderate diffuse staining pattern in the molecular layer. At all time points, nuclear IR was weaker than cytoplasmic IR. The prominent cytoplasmic and developmentally regulated expression of THAP1 suggests that THAP1 may function as part of a cell surface-nucleus signaling cascade involved in terminal neural differentiation.
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Affiliation(s)
- Y Zhao
- Department of Neurology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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Diffusion-weighted magnetic resonance imaging detection of basal forebrain cholinergic degeneration in a mouse model. Neuroimage 2012; 66:133-41. [PMID: 23128077 DOI: 10.1016/j.neuroimage.2012.10.075] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 10/19/2012] [Accepted: 10/26/2012] [Indexed: 11/21/2022] Open
Abstract
Loss of basal forebrain cholinergic neurons is an early and key feature of Alzheimer's disease, and magnetic resonance imaging (MRI) volumetric measurement of the basal forebrain has recently gained attention as a potential diagnostic tool for this condition. The aim of this study was to determine whether loss of basal forebrain cholinergic neurons underpins changes which can be detected through diffusion MRI using diffusion tensor imaging (DTI) and probabilistic tractography in a mouse model. To cause selective basal forebrain cholinergic degeneration, the toxin saporin conjugated to a p75 neurotrophin receptor antibody (mu-p75-SAP) was used. This resulted in ~25% loss of the basal forebrain cholinergic neurons and significant loss of terminal cholinergic projections in the hippocampus, as determined by histology. To test whether lesion of cholinergic neurons caused basal forebrain, hippocampal, or whole brain atrophy, we performed manual segmentation analysis, which revealed no significant atrophy in lesioned animals compared to controls (Rb-IgG-SAP). However, analysis by DTI of the basal forebrain area revealed a significant increase in fractional anisotropy (FA; +7.7%), mean diffusivity (MD; +6.1%), axial diffusivity (AD; +8.5%) and radial diffusivity (RD; +4.0%) in lesioned mice compared to control animals. These parameters strongly inversely correlated with the number of choline acetyl transferase-positive neurons, with FA showing the greatest association (r(2)=0.72), followed by MD (r(2)=0.64), AD (r(2)=0.64) and RD (r(2)=0.61). Moreover, probabilistic tractography analysis of the septo-hippocampal tracts originating from the basal forebrain revealed an increase in streamline MD (+5.1%) and RD (+4.3%) in lesioned mice. This study illustrates that moderate loss of basal forebrain cholinergic neurons (representing only a minor proportion of all septo-hippocampal axons) can be detected by measuring either DTI parameters of the basal forebrain nuclei or tractography parameters of the basal forebrain tracts. These findings provide increased support for using DTI and probabilistic tractography as non-invasive tools for diagnosing and/or monitoring the progression of conditions affecting the integrity of the basal forebrain cholinergic system in humans, including Alzheimer's disease.
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Parthasarathy G, Philipp MT. Review: apoptotic mechanisms in bacterial infections of the central nervous system. Front Immunol 2012; 3:306. [PMID: 23060884 PMCID: PMC3463897 DOI: 10.3389/fimmu.2012.00306] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 09/15/2012] [Indexed: 01/18/2023] Open
Abstract
In this article we review the apoptotic mechanisms most frequently encountered in bacterial infections of the central nervous system (CNS). We focus specifically on apoptosis of neural cells (neurons and glia), and provide first an overview of the phenomenon of apoptosis itself and its extrinsic and intrinsic pathways. We then describe apoptosis in the context of infectious diseases and inflammation caused by bacteria, and review its role in the pathogenesis of the most relevant bacterial infections of the CNS.
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Affiliation(s)
- Geetha Parthasarathy
- Division of Bacteriology and Parasitology, Tulane National Primate Research Center, Tulane University Covington, LA, USA
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Ostrakhovitch EA, Semenikhin OA. The role of redox environment in neurogenic development. Arch Biochem Biophys 2012; 534:44-54. [PMID: 22910298 DOI: 10.1016/j.abb.2012.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 07/19/2012] [Accepted: 08/03/2012] [Indexed: 10/28/2022]
Abstract
The dynamic changes of cellular redox elements during neurogenesis allow the control of specific programs for selective lineage progression. There are many redox couples that influence the cellular redox state. The shift from a reduced to an oxidized state and vice versa may act as a cellular switch mechanism of stem cell mode of action from proliferation to differentiation. The redox homeostasis ensures proper functioning of redox-sensitive signaling pathways through oxidation/reduction of critical cysteine residues on proteins involved in signal transduction. This review presents the current knowledge on the relation between changes in the cellular redox environment and stem cell programming in the course of commitment to a restricted neural lineage, focusing on in vivo neurogenesis and in vitro neuronal differentiation. The first two sections outline the main systems that control the intracellular redox environment and make it more oxidative or reductive. The last section provides the background on redox-sensitive signaling pathways that regulate neurogenesis.
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Affiliation(s)
- E A Ostrakhovitch
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7.
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Wang Y, Zhong J, Xu H, Wei W, Dong J, Yu F, Wang Y, Gong J, Shan Z, Teng W, Chen J. Perinatal iodine deficiency and hypothyroidism increase cell apoptosis and alter doublecortin and reelin protein expressions in rat cerebellum. Arch Med Res 2012; 43:255-64. [PMID: 22595232 DOI: 10.1016/j.arcmed.2012.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 04/20/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND AIMS Adequate thyroid hormone is critical for cerebellar development. Developmental hypothyroidism induced by iodine deficiency during the perinatal period results in permanent impairments of cerebellar development with an unclear mechanism. In the present study we investigated effects of perinatal iodine deficiency and hypothyroidism on cerebellar cell apoptosis, doublecortin (Dcx) and reelin. Apoptosis is an essential part of neural development. Dcx and reelin are two important molecules involved in neuronal migration, structure, and development in cerebellum. METHODS Two developmental rat models were created by administering dam rats with either iodine-deficient diet or propylthiouracil (PTU, 5 ppm or 15 ppm)-added drinking water from gestational day (GD) 6 until postnatal day (PND) 28. TUNEL assay and protein levels of Dcx and reelin in cerebella were assessed on PND14, 21 and 28. RESULTS Apoptotic cells were increased in the iodine-deficient and PTU-treated rats. Dcx protein levels in the cerebella of iodine-deficient and PTU-treated rats were significantly downregulated on PND14. Interestingly, iodine deficiency and PTU treatment upregulated the levels of Dcx protein on PND21 and 28. Reelin expressions in iodine-deficient and PTU-treated rats were significantly decreased on PND14 and 21. On PND28, reelin expressions of three treated groups were still lower than control group, although without significant difference. CONCLUSIONS These findings may implicate alterations in cell apoptosis and levels of Dcx and reelin in the impairments of cerebellar development induced by developmental iodine deficiency and hypothyroidism.
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Affiliation(s)
- Yi Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, PR China
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Kim JY, Choi SY, Kim H, Sun W. Effect of Strychinine, a Glycine Inhibitor, on the Programmed Cell Death of Motoneurons during the Chick Development. Exp Neurobiol 2012; 20:176-80. [PMID: 22355262 PMCID: PMC3268151 DOI: 10.5607/en.2011.20.4.176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Accepted: 05/17/2011] [Indexed: 11/19/2022] Open
Abstract
In this study, we report that the treatment of strychinine (STR), an inhibitor of glycine receptor, induced premature onset of programmed cell death (PCD) of developing chick motoneurons (MNs). Treatment of STR on E4 chick embryo increased the apoptosis of MN on E5 when MN PCD does not occur normally. On the other hand, treatment of STR from E3 or E5 for 24 hours did not significantly influence the extent of MN PCD, indicating that the STR effect is developmental stage-specific. However, the expression of glycine receptor isoform was low on E3-4, and other glycine receptor antagonists did not exhibit PCD-promoting activity, suggesting that the STR action on PCD is not related to the glycine receptor activation. Identification of the target molecule for STR action may provide novel mechanism how the onset of developmental PCD is regulated.
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Affiliation(s)
- Joo Yeon Kim
- Department of Anatomy, BK21 Program, Korea University College of Medicine, Seoul 136-705, Korea
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Liu C, Bakeri H, Li T, Swaroop A. Regulation of retinal progenitor expansion by Frizzled receptors: implications for microphthalmia and retinal coloboma. Hum Mol Genet 2012; 21:1848-60. [PMID: 22228100 DOI: 10.1093/hmg/ddr616] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Nineteen Wnt ligands and 10 Frizzled (Fz) receptors mediate multiple distinct cellular events during neuronal development. However, their precise roles in cell-type specification and organogenesis are poorly delineated because of overlapping functions and expression profiles. Here, we have explored the role of two closely related Frizzled receptors, Fz5 and Fz8, in mouse retinal development. We previously showed that Fz5(-/-) mice exhibit mild coloboma and microphthalmia at ~50% penetrance. Fz8 expression overlaps with Fz5 in the neural retina and optic fissure/disc. Mice lacking Fz8 show minimal eye and retinal defects. The embryos lacking both Fz5 and Fz8 die early in development, but a majority of triallelic Fz5(-/-);Fz8(+/-) mutants survive until birth. The triallelic mutant develops severe retinal coloboma and microphthalmia with full penetrance. At the cellular level, impaired neurogenesis is indicated by increased early-born retinal neurons that result from accelerated cell cycle exit of progenitors. Deficiency of apical retinal neuroepithelium is indicated by altered localization of apical junction markers, such as atypical protein kinase C, RhoA and β-catenin. Hes1 expression, which is critical for retinal progenitor expansion, is down-regulated in the triallelic mutant mouse. Furthermore, blocking Frizzled receptors in cultured retinal explants led to basally shifted divisions of retinal progenitors. Together, our studies suggest a dose-dependent regulation of signaling by Fz5 and Fz8 in optic fissure/disc formation and progenitor expansion.
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Affiliation(s)
- Chunqiao Liu
- Neurobiology Neurodegeneration and Repair Laboratory, National Eye Institute, Bethesda, MD 20892, USA.
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Abstract
Mild traumatic brain injury, especially sport-related concussion, is common among young persons. Consequences of transient pathophysiologic dysfunction must be considered in the context of a developing or immature brain, as must the potential for an accumulation of damage with repeated exposure. This review summarizes the underlying neurometabolic cascade of concussion, with emphasis on the young brain in terms of acute pathophysiology, vulnerability, alterations in plasticity and activation, axonal injury, and cumulative risk from chronic, repetitive damage, and discusses their implications in the context of clinical care for the concussed youth, highlighting areas for future investigation.
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Affiliation(s)
- Daniel W Shrey
- Division of Pediatric Neurology, Department of Pediatrics, David Geffen School of Medicine at UCLA, Mattel Children's Hospital, Los Angeles, CA 90095, USA.
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A perspective on neuronal cell death signaling and neurodegeneration. Mol Neurobiol 2010; 42:25-31. [PMID: 20480262 DOI: 10.1007/s12035-010-8128-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Accepted: 04/05/2010] [Indexed: 12/12/2022]
Abstract
Although neuronal cell death through apoptotic pathways represents a common feature of dysferopathies, the canonical apoptotic changes familiar from nonneuronal cells are late events. Loss of neuronal function occurs at a much early time, when synaptic-based neuronal connectivity fails. In this context, apoptotic pathways may normally serve a cleanup role, rather than a pathogenic one. Reframing the consideration of cell death in the nervous system to include the early stages of axonal degeneration provides a better understanding of the roles played by various apoptotic signaling pathways in neurodegenerative diseases. Focusing on disease-specific mechanisms that initiate the sequence that eventually leads to neuronal loss should facilitate development of therapies that preserve neuronal function and neuronal numbers.
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Haupt C, Kloos K, Faus-Kessler T, Huber AB. Semaphorin 3A-Neuropilin-1 signaling regulates peripheral axon fasciculation and pathfinding but not developmental cell death patterns. Eur J Neurosci 2010; 31:1164-72. [PMID: 20345923 DOI: 10.1111/j.1460-9568.2010.07154.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In early development, an excess of neurons is generated, of which later about half will be lost by cell death due to a limited supply of trophic support by their respective target areas. However, some of the neurons die when their axons have not yet reached their target, thus suggesting that additional causes of developmental cell death exist. Semaphorin 3A (Sema3A), in addition to its function as a guidance cue and mediator of timing and fasciculation of motor and sensory axon outgrowth, can also induce death of sensory neurons in vitro. However, it is unknown whether Neuropilin-1 (Npn-1), its binding receptor in axon guidance, also mediates the death-inducing activity. We show here that abolished Sema3A-Npn-1 signaling does not influence the cell death patterns of motor or sensory neurons in mouse during the developmental wave of programmed cell death. The number of motor and sensory neurons was unchanged at embryonic day 15.5 when this wave is concluded. Interestingly, the defasciculation of early motor and sensory projections that is observed in the absence of Sema3A or Npn-1 persists to postnatal stages. Thus, Sema3A-Npn-1 signaling plays an important role in the guidance and fasciculation of motor and sensory axons but does not contribute to the developmental elimination of these neurons.
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Affiliation(s)
- Corinna Haupt
- Institute of Developmental Genetics, Helmholtz Zentrum München-German Research Center for Environmental Health, Ingolstädter Landstrasse 1, D-85764 Munich/Neuherberg, Germany
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