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Gheusi G, Lepousez G, Lledo PM. Adult-born neurons in the olfactory bulb: integration and functional consequences. Curr Top Behav Neurosci 2012; 15:49-72. [PMID: 22976274 DOI: 10.1007/7854_2012_228] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The generation of new neurons is sustained throughout life in the olfactory system. In recent years, tremendous progress has been made toward understanding the proliferation, differentiation, migration, and integration of newborn neurons in the olfactory bulb. Here, we discuss recent findings that shed light on different aspects of the integration of adult-born neurons into olfactory circuitry and its significance for behavior.
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Affiliation(s)
- Gilles Gheusi
- Laboratoire Perception et Mémoire, Institut Pasteur, CNRS URA 2182, 25 rue du Dr Roux, 75724, Paris Cedex 15, France,
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202
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Zamora-Berridi GJ, Pendleton C, Ruiz G, Cohen-Gadol AA, Quiñones-Hinojosa A. Santiago Ramón y Cajal and Harvey Cushing: two forefathers of neuroscience and neurosurgery. World Neurosurg 2011; 76:466-76. [PMID: 22152577 DOI: 10.1016/j.wneu.2011.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 02/05/2011] [Accepted: 04/01/2011] [Indexed: 01/18/2023]
Abstract
OBJECTIVE To summarize the extraordinary accomplishments, and the commonalities, between Santiago Ramon y Cajal and Harvey Williams Cushing. METHODS Existing literature describing the lives and achievements of Ramón y Cajal and Cushing, as well as personal communication, and the surgical records of the Johns Hopkins Hospital, from 1896 to 1912, were reviewed. RESULTS Both Ramón y Cajal and Cushing were men of unusually broad interests and talents, and these shared characteristics undoubtedly influenced the career paths and scientific investigations they pursued. Although Santiago Ramón y Cajal and Harvey Williams Cushing never directly interacted, the links between them can be traced through some of their disciples, including Pío del Río Hortega, Wilder Penfield, and Percival Bailey. CONCLUSIONS Ramón y Cajal and Cushing are widely considered the forefathers of neuroscience and neurosurgery, respectively, and their discoveries have made lasting impressions on both the scientific and medical communities.
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203
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Gil-Ranedo J, Mendiburu-Eliçabe M, García-Villanueva M, Medina D, del Álamo M, Izquierdo M. An off-target nucleostemin RNAi inhibits growth in human glioblastoma-derived cancer stem cells. PLoS One 2011; 6:e28753. [PMID: 22174890 PMCID: PMC3236221 DOI: 10.1371/journal.pone.0028753] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 11/14/2011] [Indexed: 12/03/2022] Open
Abstract
Glioblastomas (GBM) may contain a variable proportion of active cancer stem cells (CSCs) capable of self-renewal, of aggregating into CD133+ neurospheres, and to develop intracranial tumors that phenocopy the original ones. We hypothesized that nucleostemin may contribute to cancer stem cell biology as these cells share characteristics with normal stem cells. Here we report that nucleostemin is expressed in GBM-CSCs isolated from patient samples, and that its expression, conversely to what it has been described for ordinary stem cells, does not disappear when cells are differentiated. The significance of nucleostemin expression in CSCs was addressed by targeting the corresponding mRNA using lentivirally transduced short hairpin RNA (shRNA). In doing so, we found an off-target nucleostemin RNAi (shRNA22) that abolishes proliferation and induces apoptosis in GBM-CSCs. Furthermore, in the presence of shRNA22, GBM-CSCs failed to form neurospheres in vitro or grow on soft agar. When these cells are xenotransplanted into the brains of nude rats, tumor development is significantly delayed. Attempts were made to identify the primary target/s of shRNA22, suggesting a transcription factor involved in one of the MAP-kinases signaling-pathways or multiple targets. The use of this shRNA may contribute to develop new therapeutic approaches for this incurable type of brain tumor.
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Affiliation(s)
- Jon Gil-Ranedo
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Instituto Sanitario Ramón y Cajal, Madrid, Spain
| | - Marina Mendiburu-Eliçabe
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Instituto Sanitario Ramón y Cajal, Madrid, Spain
| | | | - Diego Medina
- Servicio de Neurocirugía, Hospital Universitario Ramón y Cajal, Instituto Sanitario Ramón y Cajal, Madrid, Spain
| | - Marta del Álamo
- Servicio de Neurocirugía, Hospital Universitario Ramón y Cajal, Instituto Sanitario Ramón y Cajal, Madrid, Spain
| | - Marta Izquierdo
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Instituto Sanitario Ramón y Cajal, Madrid, Spain
- * E-mail:
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204
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Masi G, Brovedani P. The hippocampus, neurotrophic factors and depression: possible implications for the pharmacotherapy of depression. CNS Drugs 2011; 25:913-31. [PMID: 22054117 DOI: 10.2165/11595900-000000000-00000] [Citation(s) in RCA: 176] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Depression is a prevalent, highly debilitating mental disorder affecting up to 15% of the population at least once in their lifetime, with huge costs for society. Neurobiological mechanisms of depression are still not well known, although there is consensus about interplay between genetic and environmental factors. Antidepressant medications are frequently used in depression, but at least 50% of patients are poor responders, even to more recently discovered medications. Furthermore, clinical response only occurs following weeks to months of treatment and only chronic treatment is effective, suggesting that actions beyond the rapidly occurring effect of enhancing monoaminergic systems, such as adaptation of these systems, are responsible for the effects of antidepressants. Recent studies indicate that an impairment of synaptic plasticity (neurogenesis, axon branching, dendritogenesis and synaptogenesis) in specific areas of the CNS, particularly the hippocampus, may be a core factor in the pathophysiology of depression. The abnormal neural plasticity may be related to alterations in the levels of neurotrophic factors, namely brain-derived neurotrophic factor (BDNF), which play a central role in plasticity. As BDNF is repressed by stress, epigenetic regulation of the BDNF gene may play an important role in depression. The hippocampus is smaller in depressed patients, although it is unclear whether smaller size is a consequence of depression or a pre-existing, vulnerability marker for depression. Environmental stressors triggering activation of the hypothalamic-pituitary-adrenal axis cause the brain to be exposed to corticosteroids, affecting neurobehavioural functions with a strong downregulation of hippocampal neurogenesis, and are a major risk factor for depression. Antidepressant treatment increases BDNF levels, stimulates neurogenesis and reverses the inhibitory effects of stress, but this effect is evident only after 3-4 weeks of administration, the time course for maturation of new neurons. The ablation of hippocampal neurogenesis blocks the behavioural effects of antidepressants in animal models. The above findings suggest new possible targets for the pharmacotherapy of depression such as neurotrophic factors, their receptors and related intracellular signalling cascades; agents counteracting the effects of stress on hippocampal neurogenesis (including antagonists of corticosteroids, inflammatory cytokines and their receptors); and agents facilitating the activation of gene expression and increasing the transcription of neurotrophins in the brain.
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Affiliation(s)
- Gabriele Masi
- IRCCS Stella Maris, Scientific Institute of Child Neurology and Psychiatry, Calambrone, Pisa, Italy.
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205
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Calabrese F, Molteni R, Riva MA. Antistress properties of antidepressant drugs and their clinical implications. Pharmacol Ther 2011; 132:39-56. [DOI: 10.1016/j.pharmthera.2011.05.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 05/09/2011] [Indexed: 02/07/2023]
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206
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Doeppner TR, Bretschneider E, Doehring M, Segura I, Sentürk A, Acker-Palmer A, Hasan MR, ElAli A, Hermann DM, Bähr M. Enhancement of endogenous neurogenesis in ephrin-B3 deficient mice after transient focal cerebral ischemia. Acta Neuropathol 2011; 122:429-42. [PMID: 21779764 PMCID: PMC3291816 DOI: 10.1007/s00401-011-0856-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 07/01/2011] [Accepted: 07/02/2011] [Indexed: 01/26/2023]
Abstract
Cerebral ischemia stimulates endogenous neurogenesis. However, the functional relevance of this phenomenon remains unclear because of poor survival and low neuronal differentiation rates of newborn cells. Therefore, further studies on mechanisms regulating neurogenesis under ischemic conditions are required, among which ephrin-ligands and ephrin-receptors (Eph) are an interesting target. Although Eph/ephrin proteins like ephrin-B3 are known to negatively regulate neurogenesis under physiological conditions, their role in cerebral ischemia is largely unknown. We therefore studied neurogenesis, brain injury and functional outcome in ephrin-B3−/− (knockout) and ephrin-B3+/+ (wild-type) mice submitted to cerebral ischemia. Induction of stroke resulted in enhanced cell proliferation and neuronal differentiation around the lesion site of ephrin-B3−/− compared to ephrin-B3+/+ mice. However, prominent post-ischemic neurogenesis in ephrin-B3−/− mice was accompanied by significantly increased ischemic injury and motor coordination deficits that persisted up to 4 weeks. Ischemic injury in ephrin-B3−/− mice was associated with a caspase-3-dependent activation of the signal transducer and activator of transcription 1 (STAT1). Whereas inhibition of caspase-3 had no effect on brain injury in ephrin-B3+/+ animals, infarct size in ephrin-B3−/− mice was strongly reduced, suggesting that aggravated brain injury in these animals might involve a caspase-3-dependent activation of STAT1. In conclusion, post-ischemic neurogenesis in ephrin-B3−/− mice is strongly enhanced, but fails to contribute to functional recovery because of caspase-3-mediated aggravation of ischemic injury in these animals. Our results suggest that ephrin-B3 might be an interesting target for overcoming some of the limitations of further cell-based therapies in stroke.
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Affiliation(s)
- Thorsten R Doeppner
- Department of Neurology, University of Duisburg-Essen Medical School, Hufelandstr. 55, 45122, Essen, Germany.
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207
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Södersten P, Bergh C, Zandian M, Ioakimidis I. Obesity and the brain. Med Hypotheses 2011; 77:371-3. [DOI: 10.1016/j.mehy.2011.05.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 05/15/2011] [Indexed: 12/27/2022]
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208
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Nakada M, Hayashi Y, Hamada JI. Role of Eph/ephrin tyrosine kinase in malignant glioma. Neuro Oncol 2011; 13:1163-70. [PMID: 21856686 DOI: 10.1093/neuonc/nor102] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Accumulating evidence has revealed that the tyrosine kinases play a major role in glioma proliferation and invasion. The largest family of tyrosine kinases, the Eph family, and its ligands, the ephrins, are frequently overexpressed in glioma, suggesting important roles for their bidirectional signals in glioma pathobiology. Ephs bind to cell surface-associated ephrin ligands on neighboring cells and have many biological functions during embryonic development of the central nervous system, including axon mapping, cell migration, and angiogenesis. Recent findings suggest that Eph/ephrin signaling affects glioma cell growth, migration, and invasion in vitro and in vivo. However, their roles in glioma seem complex, because both tumor growth promoter and suppressor potentials have been ascribed to Ephs and ephrins. Here, we review recent advances in research on the role of Eph/ephrin signaling in glioma and suggest that the Eph/ephrin system could be a potential target of glioma therapy.
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Affiliation(s)
- Mitsutoshi Nakada
- Department of Neurosurgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
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209
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Noguès X, Corsini MM, Marighetto A, Abrous DN. Functions for adult neurogenesis in memory: an introduction to the neurocomputational approach and to its contribution. Behav Brain Res 2011; 227:418-25. [PMID: 21856335 DOI: 10.1016/j.bbr.2011.08.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 08/04/2011] [Accepted: 08/06/2011] [Indexed: 01/26/2023]
Abstract
Until recently, it was believed that the introduction of new neurons in neuronal networks was incompatible with memory function. Since the rediscovery of adult hippocampal neurogenesis, behavioral data demonstrate that adult neurogenesis is required for memory processing. We examine neurocomputational studies to identify which basic mechanisms involved in memory might be mediated by adult neurogenesis. Mainly, adult neurogenesis might be involved in the reduction of catastrophic interference and in a time-related pattern separation function. Artificial neuronal networks suggest that the selective recruitment of new-born or old neurons is not stochastic, but depends on environmental requirements. This leads us to propose the novel concept of "soft-supervision". Soft-supervision would be a biologically plausible process, by which the environment is able to influence activation and learning rules of neurons differentially.
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Affiliation(s)
- X Noguès
- INSERM U862, Neurocenter Magendie, Pathophysiology of Declarative Memory group, Bordeaux F33077, France.
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210
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Li Y, Luo J, Lau WM, Zheng G, Fu S, Wang TT, Zeng HP, So KF, Chung SK, Tong Y, Liu K, Shen J. Caveolin-1 plays a crucial role in inhibiting neuronal differentiation of neural stem/progenitor cells via VEGF signaling-dependent pathway. PLoS One 2011; 6:e22901. [PMID: 21826216 PMCID: PMC3149620 DOI: 10.1371/journal.pone.0022901] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 07/08/2011] [Indexed: 01/17/2023] Open
Abstract
In the present study, we aim to elucidate the roles of caveolin-1(Cav-1), a 22 kDa protein in plasma membrane invaginations, in modulating neuronal differentiation of neural progenitor cells (NPCs). In the hippocampal dentate gyrus, we found that Cav-1 knockout mice revealed remarkably higher levels of vascular endothelial growth factor (VEGF) and the more abundant formation of newborn neurons than wild type mice. We then studied the potential mechanisms of Cav-1 in modulating VEGF signaling and neuronal differentiation in isolated cultured NPCs under normoxic and hypoxic conditions. Hypoxic embryonic rat NPCs were exposed to 1% O2 for 24 h and then switched to 21% O2 for 1, 3, 7 and 14 days whereas normoxic NPCs were continuously cultured with 21% O2. Compared with normoxic NPCs, hypoxic NPCs had down-regulated expression of Cav-1 and up-regulated VEGF expression and p44/42MAPK phosphorylation, and enhanced neuronal differentiation. We further studied the roles of Cav-1 in inhibiting neuronal differentiation by using Cav-1 scaffolding domain peptide and Cav-1-specific small interfering RNA. In both normoxic and hypoxic NPCs, Cav-1 peptide markedly down-regulated the expressions of VEGF and flk1, decreased the phosphorylations of p44/42MAPK, Akt and Stat3, and inhibited neuronal differentiation, whereas the knockdown of Cav-1 promoted the expression of VEGF, phosphorylations of p44/42MAPK, Akt and Stat3, and stimulated neuronal differentiation. Moreover, the enhanced phosphorylations of p44/42MAPK, Akt and Stat3, and neuronal differentiation were abolished by co-treatment of VEGF inhibitor V1. These results provide strong evidence to prove that Cav-1 can inhibit neuronal differentiation via down-regulations of VEGF, p44/42MAPK, Akt and Stat3 signaling pathways, and that VEGF signaling is a crucial target of Cav-1. The hypoxia-induced down-regulation of Cav-1 contributes to enhanced neuronal differentiation in NPCs.
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Affiliation(s)
- Yue Li
- School of Chinese Medicine, The University of Hong Kong, Hong Kong SAR, China
- Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Hong Kong SAR, China
| | - Jianmin Luo
- School of Chinese Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Wui-Man Lau
- Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Hong Kong SAR, China
- State Key Laboratory of Brain and Cognitive Sciences, Department of Anatomy, The University of Hong Kong, Hong Kong SAR, China
| | - Guoqing Zheng
- School of Chinese Medicine, The University of Hong Kong, Hong Kong SAR, China
- Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical College, Wenzhou, China
| | - Shuping Fu
- School of Chinese Medicine, The University of Hong Kong, Hong Kong SAR, China
- Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Hong Kong SAR, China
| | - Ting-Ting Wang
- Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Hong Kong SAR, China
- Institute of Functional Molecule, School of Chemistry, South China University of Technology, Guangzhou, China
| | - He-Ping Zeng
- Institute of Functional Molecule, School of Chemistry, South China University of Technology, Guangzhou, China
| | - Kwok-Fai So
- Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Hong Kong SAR, China
- State Key Laboratory of Brain and Cognitive Sciences, Department of Anatomy, The University of Hong Kong, Hong Kong SAR, China
| | - Sookja Kim Chung
- Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Hong Kong SAR, China
- State Key Laboratory of Brain and Cognitive Sciences, Department of Anatomy, The University of Hong Kong, Hong Kong SAR, China
| | - Yao Tong
- School of Chinese Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Kejian Liu
- Center of Biomedical Research Excellence, College of Pharmacy, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Jiangang Shen
- School of Chinese Medicine, The University of Hong Kong, Hong Kong SAR, China
- Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Hong Kong SAR, China
- * E-mail:
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211
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Gonzalez Andino SL, Herrera-Rincon C, Panetsos F, Grave de Peralta R. Combining BMI Stimulation and Mathematical Modeling for Acute Stroke Recovery and Neural Repair. Front Neurosci 2011; 5:87. [PMID: 21811433 PMCID: PMC3144440 DOI: 10.3389/fnins.2011.00087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Accepted: 06/24/2011] [Indexed: 12/13/2022] Open
Abstract
Rehabilitation is a neural plasticity-exploiting approach that forces undamaged neural circuits to undertake the functionality of other circuits damaged by stroke. It aims to partial restoration of the neural functions by circuit remodeling rather than by the regeneration of damaged circuits. The core hypothesis of the present paper is that – in stroke – brain machine interfaces (BMIs) can be designed to target neural repair instead of rehabilitation. To support this hypothesis we first review existing evidence on the role of endogenous or externally applied electric fields on all processes involved in CNS repair. We then describe our own results to illustrate the neuroprotective and neuroregenerative effects of BMI-electrical stimulation on sensory deprivation-related degenerative processes of the CNS. Finally, we discuss three of the crucial issues involved in the design of neural repair-oriented BMIs: when to stimulate, where to stimulate and – the particularly important but unsolved issue of – how to stimulate. We argue that optimal parameters for the electrical stimulation can be determined from studying and modeling the dynamics of the electric fields that naturally emerge at the central and peripheral nervous system during spontaneous healing in both, experimental animals and human patients. We conclude that a closed-loop BMI that defines the optimal stimulation parameters from a priori developed experimental models of the dynamics of spontaneous repair and the on-line monitoring of neural activity might place BMIs as an alternative or complement to stem-cell transplantation or pharmacological approaches, intensively pursued nowadays.
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Affiliation(s)
- Sara L Gonzalez Andino
- Electrical Neuroimaging Group, Department of Neurology, Geneva University Hospital Geneva, Switzerland
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212
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Weinandy F, Ninkovic J, Götz M. Restrictions in time and space--new insights into generation of specific neuronal subtypes in the adult mammalian brain. Eur J Neurosci 2011; 33:1045-54. [PMID: 21395847 DOI: 10.1111/j.1460-9568.2011.07602.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Key questions in regard to neuronal repair strategies are which cells are best suited to regenerate specific neuronal subtypes and how much of a neuronal circuit needs to persist in order to allow its functional repair. Here we discuss recent findings in the field of adult neurogenesis, which shed new light on these questions. Neural stem cells in the adult brain generate very distinct types of neurons depending on their regional and temporal specification. Moreover, distinct brain regions differ in the mode of neuron addition in adult neurogenesis, suggesting that different brain circuits may be able to cope differently with the incorporation of new neurons. These new insights are then considered in regard to the choice of cells with the appropriate region-specific identity for repair strategies.
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Affiliation(s)
- Franziska Weinandy
- Institute of Stem Cell Research, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstr. 1, 85764 München/Neuherberg, Germany
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213
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Abstract
Understanding the cellular mechanisms underlying learning and memory is a major challenge in neurobiology. Structural and functional changes occurring in the hippocampus such as synaptic remodeling and long-term potentiation are key signatures of long-term memory processes. The discovery of a de novo hippocampal production of neurons in the adult brain has been a breakthrough in the field of plasticity and memory, introducing a new actor that could sustain memory processes. Here we will review our current knowledge on the role of these adult new neurons in memory. In particular we will provide evidence showing that they are required for learning and memory and that an alteration in their production rate or maturation leads to memory impairments. Through a thorough survey of the literature, we will also acknowledge that there are many controversies regarding the specific role played by newborn neurons. The emerging picture is that they are involved in the establishment of spatiotemporal relationships among multiple environmental cues for the flexible use of the acquired information. Indeed, newborn neurons have been found to be required for separating events based on their spatial and temporal characteristics, a process that preserves the uniqueness of a memory representation. Thus, adult-born neurons are required for allocentric space representation, for long-term memory retention and for flexible inferential memory expression. Finally, we will conclude by highlighting directions for future research, emphasizing that the exact participation of newborn neurons in memory processes will not be approached without considering the hippocampal network in general.
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Affiliation(s)
- Muriel Koehl
- Neurogenesis and Pathophysiology Laboratory, INSERM 862, Bordeaux, France
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214
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Prvulovic D, Bokde ALW, Faltraco F, Hampel H. Functional magnetic resonance imaging as a dynamic candidate biomarker for Alzheimer's disease. Prog Neurobiol 2011; 95:557-69. [PMID: 21722703 DOI: 10.1016/j.pneurobio.2011.05.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 05/24/2011] [Accepted: 05/27/2011] [Indexed: 11/18/2022]
Abstract
During the last two decades, imaging of neural activation has become an invaluable tool for assessing the functional organization of the human brain in vivo. Due to its widespread application in neuroscience, functional neuroimaging has raised the interest of clinical researchers in its possible use as a diagnostic biomarker. A hallmark feature of many neurodegenerative diseases is their chronic non-linear dynamic and highly complex preclinical course. Neurodegenerative diseases unfold over years to decades through clinically silent and asymptomatic stages of early adaptive, compensatory to pathophysiological (i.e. actively neurodegenerative) and decompensatory mechanisms in the brain - phases that are increasingly being considered as critical for primary and secondary preventive and therapeutic measures. Emerging evidence supports the concept of a potentially fully reversible functional phase that may precede the onset of micro- and macrostructural and cognitive decline, a potentially late-stage "neurodegenerative" phase of a primary neurodegenerative disorder. Alzheimer's disease serves as an ideal model to test this hypothesis supported by the neural network model of the healthy and diseased brain. Being highly dynamic in nature, brain activation and neuronal network functional connectivity represent not only candidate diagnostic but also candidate surrogate markers for interventional trials. Potential caveats of functional imaging are critically reviewed with focus on confound variables such as altered neurovascular coupling as well as parameters related to task- and study design.
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Affiliation(s)
- David Prvulovic
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe-University of Frankfurt, Frankfurt, Germany.
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215
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Blumenfeld-Katzir T, Pasternak O, Dagan M, Assaf Y. Diffusion MRI of structural brain plasticity induced by a learning and memory task. PLoS One 2011; 6:e20678. [PMID: 21701690 PMCID: PMC3119075 DOI: 10.1371/journal.pone.0020678] [Citation(s) in RCA: 200] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 05/10/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Activity-induced structural remodeling of dendritic spines and glial cells was recently proposed as an important factor in neuroplasticity and suggested to accompany the induction of long-term potentiation (LTP). Although T1 and diffusion MRI have been used to study structural changes resulting from long-term training, the cellular basis of the findings obtained and their relationship to neuroplasticity are poorly understood. METHODOLOGY/PRINCIPAL FINDING Here we used diffusion tensor imaging (DTI) to examine the microstructural manifestations of neuroplasticity in rats that performed a spatial navigation task. We found that DTI can be used to define the selective localization of neuroplasticity induced by different tasks and that this process is age-dependent in cingulate cortex and corpus callosum and age-independent in the dentate gyrus. CONCLUSION/SIGNIFICANCE We relate the observed DTI changes to the structural plasticity that occurs in astrocytes and discuss the potential of MRI for probing structural neuroplasticity and hence indirectly localizing LTP.
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Affiliation(s)
- Tamar Blumenfeld-Katzir
- Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Ofer Pasternak
- Laboratory of Mathematics in Imaging, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Michael Dagan
- Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Yaniv Assaf
- Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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216
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Dranovsky A, Leonardo ED. Is there a role for young hippocampal neurons in adaptation to stress? Behav Brain Res 2011; 227:371-5. [PMID: 21621559 DOI: 10.1016/j.bbr.2011.05.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 04/11/2011] [Accepted: 05/10/2011] [Indexed: 10/18/2022]
Abstract
The hippocampus has been implicated in many cognitive and emotional behaviors and in the physiology of the stress response. Within the hippocampus, the dentate gyrus has been implicated in the detection of novelty. The dentate is also a major target for stress hormones and modulates the hypothalamic-pituitary-adrenal (HPA) axis response to stress. Whether these functions of the dentate integrate or segregate remains unknown, as most investigations of its role in stress and learning are separate. Since the exciting discovery of adult neurogenesis in the dentate gyrus, adult-born neurons have been implicated in both novelty detection and the stress response. In this perspective we will discuss the literature that implicates the hippocampus, and potentially, adult-born neurons in these two functions. We will attempt to reconcile the seemingly contradictory behavioral results for the function of adult-born neurons. Finally, we will speculate that a key function of adult-born neurons within hippocampal function may be to modulate the stress response and perhaps assign stress salience to the sensory context.
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Affiliation(s)
- Alex Dranovsky
- Department of Psychiatry, Division of Integrative Neuroscience, Columbia University and the New York State Psychiatric Institute, 1051 Riverside Dr. Box 87, New York, NY 10032, USA.
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Ohira K. Injury-induced neurogenesis in the mammalian forebrain. Cell Mol Life Sci 2011; 68:1645-56. [PMID: 21042833 PMCID: PMC11115059 DOI: 10.1007/s00018-010-0552-y] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 09/30/2010] [Accepted: 09/30/2010] [Indexed: 10/18/2022]
Abstract
It has been accepted that new neurons are added to the olfactory bulb and the hippocampal dentate gyrus throughout life in the healthy adult mammalian brain. Recent studies have clarified that brain insult raises the proliferation of neural stem cells/neural progenitor cells existing in the subventricular zone and the subgranular zone, which become sources of new neurons for the olfactory bulb and the dentate gyrus, respectively. Interestingly, convincing data has shown that brain insult invokes neurogenesis in various brain regions, such as the hippocampal cornu ammonis region, striatum, and cortex. These reports suggest that neural stem cells/neural progenitor cells, which can be activated by brain injury, might be broadly located in the adult brain or that new neurons may migrate widely from the neurogenic regions. This review focuses on brain insult-induced neurogenesis in the mammalian forebrain, especially in the neocortex.
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Affiliation(s)
- Koji Ohira
- Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, 470-1192, Japan.
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218
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Massa F, Koehl M, Wiesner T, Grosjean N, Revest JM, Piazza PV, Abrous DN, Oliet SHR. Conditional reduction of adult neurogenesis impairs bidirectional hippocampal synaptic plasticity. Proc Natl Acad Sci U S A 2011; 108:6644-9. [PMID: 21464314 PMCID: PMC3081011 DOI: 10.1073/pnas.1016928108] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Adult neurogenesis is a process by which the brain produces new neurons once development has ceased. Adult hippocampal neurogenesis has been linked to the relational processing of spatial information, a role attributed to the contribution of newborn neurons to long-term potentiation (LTP). However, whether newborn neurons also influence long-term depression (LTD), and how synaptic transmission and plasticity are affected as they incorporate their network, remain to be determined. To address these issues, we took advantage of a genetic model in which a majority of adult-born neurons can be selectively ablated in the dentate gyrus (DG) and, most importantly, in which neurogenesis can be restored on demand. Using electrophysiological recordings, we show that selective reduction of adult-born neurons impairs synaptic transmission at medial perforant pathway synapses onto DG granule cells. Furthermore, LTP and LTD are largely compromised at these synapses, probably as a result of an increased induction threshold. Whereas the deficits in synaptic transmission and plasticity are completely rescued by restoring neurogenesis, these synapses regain their ability to express LTP much faster than their ability to express LTD. These results demonstrate that both LTP and LTD are influenced by adult neurogenesis. They also indicate that as newborn neurons integrate their network, the ability to express bidirectional synaptic plasticity is largely improved at these synapses. These findings establish that adult neurogenesis is an important process for synaptic transmission and bidirectional plasticity in the DG, accounting for its role in efficiently integrating novel incoming information and in forming new memories.
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Affiliation(s)
- Federico Massa
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Glia-Neuron Interactions Group, F33077 Bordeaux, France
- Université de Bordeaux, F33077 Bordeaux, France
| | - Muriel Koehl
- Université de Bordeaux, F33077 Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Neurogenesis and Pathophysiology Group, F33077 Bordeaux, France
| | - Theresa Wiesner
- Université de Bordeaux, F33077 Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Endocannabinoids and Neuroadaptation Group, F33077 Bordeaux, France; and
| | - Noelle Grosjean
- Université de Bordeaux, F33077 Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Neurogenesis and Pathophysiology Group, F33077 Bordeaux, France
| | - Jean-Michel Revest
- Université de Bordeaux, F33077 Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Pathophysiology of Addiction Group, F33077 Bordeaux, France
| | - Pier-Vincenzo Piazza
- Université de Bordeaux, F33077 Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Pathophysiology of Addiction Group, F33077 Bordeaux, France
| | - Djoher Nora Abrous
- Université de Bordeaux, F33077 Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Neurogenesis and Pathophysiology Group, F33077 Bordeaux, France
| | - Stéphane H. R. Oliet
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Glia-Neuron Interactions Group, F33077 Bordeaux, France
- Université de Bordeaux, F33077 Bordeaux, France
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219
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Weiss B. Endocrine disruptors as a threat to neurological function. J Neurol Sci 2011; 305:11-21. [PMID: 21474148 DOI: 10.1016/j.jns.2011.03.014] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 03/01/2011] [Accepted: 03/03/2011] [Indexed: 12/31/2022]
Abstract
Endocrine disruption is a concept and principle whose origins can be traced to the beginnings of the environmental movement in the 1960s. It began with puzzlement about and the flaring of research on the decline of wildlife, particularly avian species. The proposed causes accented pesticides, especially persistent organochlorines such as DDT. Its scope gradually widened beyond pesticides, and, as endocrine disruption offered an explanation for the wildlife phenomena, it seemed to explain, as well, changes in fertility and disorders of male reproduction such as testicular cancer. Once disturbed gonadal hormone function became the most likely explanation, it provoked other questions. The most challenging arose because of how critical gonadal hormones are to brain function, especially as determinants of brain sexual differentiation. Pursuit of such connections has generated a robust literature embracing a broad swath of chemical classes. How endocrine disrupting chemicals influence the adult and aging brain is a question, so far mostly ignored because of the emphasis on early development, that warrants vigorous investigation. Gonadal hormones are crucial to optimal brain function during maturity and even senescence. They are pivotal to the processes of neurogenesis. They exert protective actions against neurodegenerative disorders such as dementia and support smoothly functioning cognitive activities. The limited research conducted so far on endocrine disruptors, aging, and neurogenesis argues that they should be overlooked no longer.
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Affiliation(s)
- Bernard Weiss
- Department of Environmental Medicine, University of Rochester, School of Medicine and Dentistry, Rochester, NY 14642, USA.
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220
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The role of olfactory stimulus in adult mammalian neurogenesis. Behav Brain Res 2011; 227:356-62. [PMID: 21453729 DOI: 10.1016/j.bbr.2011.03.050] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 03/08/2011] [Accepted: 03/21/2011] [Indexed: 02/06/2023]
Abstract
Neurogenesis occurs in the adult mammalian brain in discrete regions related to olfactory sensory signaling and integration. The olfactory receptor cell population is in constant turn-over through local progenitor cells. Also, newborn neurons are added to the olfactory bulbs through a major migratory route from the subventricular zone, the rostral migratory stream. The olfactory bulbs project to different brain structures, including: piriform cortex, amygdala, entorhinal cortex, striatum and hippocampus. These structures play important roles in odor identification, feeding behavior, social interactions, reproductive behavior, behavioral reinforcement, emotional responses, learning and memory. In all of these regions neurogenesis has been described in normal and in manipulated mammalian brain. These data are reviewed in the context of a sensory-behavioral hypothesis on adult neurogenesis that olfactory input modulates neurogenesis in many different regions of the brain.
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221
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Gang B, Yue C, Han N, Xue H, Li B, Sun L, Li X, Zhao Q. Limited hippocampal neurogenesis in SAMP8 mouse model of Alzheimer's disease. Brain Res 2011; 1389:183-93. [PMID: 21439270 DOI: 10.1016/j.brainres.2011.03.039] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 03/12/2011] [Accepted: 03/16/2011] [Indexed: 12/19/2022]
Abstract
Increasing adult neurogenesis in the hippocampal formation (HF) has been proposed as a potential foundation for neuronal repair in Alzheimer's disease (AD), but the evidence remains controversial. We used P8 strain of senescence-accelerated mice (SAMP8) as a model of AD to investigate changes in adult neurogenesis. We examined new proliferating cells and their survival in the dentate gyrus (DG) of the HF using 5-bromodeoxyuridine (BrdU) labeling and investigated newborn cell development and differentiation with a combination of phenotype markers. In 5-month-old SAMP8, the number of BrdU(+) cells in the DG was significantly increased relative to controls, in accordance with the rising numbers of doublecortin-positive (DCX(+)) immature neurons. Some of these BrdU(+) cells migrated to cornu ammonis 1 (CA1), possibly related to the compensation of neuronal loss. However, the capacity of neurogenesis to compensate neuronal loss during neurodegeneration was limited. First, only half of the BrdU(+) cells survived 4weeks after mitosis, and even fewer developed into neuron-specific nuclear protein positive (NeuN(+)) mature neurons. Second, the number of BrdU(+) cells and DCX(+) cells was decreased in 10-month-old SAMP8, which exhibited progressive neurodegeneration. In addition, the results provided insight into astrocytes as a crucial component of the neurogenic niche. The number of newborn astrocytes and expression of glial fibrillary acidic protein (GFAP) were diminished in the DG of SAMP8 animals, possibly explaining the insufficient neurogenesis. Thus, stimulating limited neurogenesis in AD by improving the neurogenic niche may have therapeutic potential.
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Affiliation(s)
- Baozhi Gang
- Department of Neurology, The First Clinical College, Harbin Medical University, 23rd Youzheng Street, Nangang District, Harbin, Heilongjiang Province 15001, China
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222
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Pugliese M, Rodríguez MJ, Gimeno-Bayon J, Pujadas L, Billett EE, Wells C, Mahy N. Alzheimer's disease modifies progenitor cell expression of monoamine oxidase B in the subventricular zone. J Neurosci Res 2011; 88:2588-97. [PMID: 20648649 DOI: 10.1002/jnr.22423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In the adult brain, progenitor cells remaining in the subventricular zone (SVZ) are frequently identified as glial fibrillary acidic protein (GFAP)-positive cells that retain attributes reminiscent of radial glia. Because the very high expression of monoamine oxidase B (MAO-B) in the subventricular area has been related to epithelial and astroglial expression, we sought to ascertain whether it was also expressed by progenitor cells of human control and Alzheimer's disease (AD) patients. In the SVZ, epithelial cells and astrocyte-like cells presented rich MAO-B activity and immunolabeling. Nestin-positive cells were found in the same area, showing a radial glia-like morphology. When coimmunostaining and confocal microscopy were performed, most nestin-positive cells showed MAO-B activity and labeling. The increased progenitor activity in SVZ proposed for AD patients was confirmed by the positive correlation between the SVZ nestin/MAO-B ratio and the progression of the disease. Nestin/GFAP-positive cells, devoid of MAO-B, can represent a distinct subpopulation of an earlier phase of maturation. This would indicate that MAO-B expression takes place in a further step of nestin/GFAP-positive cell differentiation. In the early AD stages, the discrete MAO-B reduction, different from the severe GFAP decrease, would reflect the capacity of this population of MAO-B-positive progenitor cells to adapt to the neurodegenerative process.
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Affiliation(s)
- Marco Pugliese
- Unitat de Bioquímica i Biologia Molecular, Facultat de Medicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
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223
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Working memory task decreases the survival of newly born neurons in hippocampus. Neurobiol Learn Mem 2011; 95:239-47. [DOI: 10.1016/j.nlm.2010.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Revised: 10/27/2010] [Accepted: 11/19/2010] [Indexed: 11/18/2022]
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224
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Mazurek B, Olze H, Haupt H, Klapp BF, Adli M, Gross J, Szczepek AJ. [Molecular biological aspects of neuroplasticity: approaches for treating tinnitus and hearing disorders]. HNO 2011; 58:973-82. [PMID: 20811868 DOI: 10.1007/s00106-010-2177-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Peripheral and central structures are involved in the onset of tinnitus. Neuronal plasticity is of special importance for the occurrence of central tinnitus and its persistent form. Neuronal plasticity is the ability of the brain to adapt its own structure (synapses, nerve cells, or even whole areas of the brain) and its organization to modified biological requirements. Neuroplasticity is an ongoing dynamic process. Generally speaking, there are two types of plasticity: synaptic and cortical. Cortical plasticity involves activity-dependent changes in size, connectivity, or in the activation pattern of cortical networks. Synaptic plasticity refers to the activity-dependent change in the strength of synaptic transmission and can affect both the morphology and physiology of the synapse. The stimulation of afferent fibers leads to long-lasting changes in synaptic transmission. This phenomenon is called long-term potentiation (LTP) or long-term depression (LTD). From the perspective of molecular biology, synaptic plasticity is of particular importance for the development of tinnitus and its persistence. Ultimately, the damage to the hair cells, auditory nerve, and excitotoxicity results in an imbalance between LTP and LTD and thus in changes of synaptic plasticity. After excessive acoustic stimulation, LTP can be induced by the increase of afferent inputs, whereas decreased afferent inputs generate LTD. The imbalance between LTP and LTD leads to changes in gene expression and involves changes in neurotransmission, in the expression of the receptors, ion channels, regulatory enzymes, and in direct changes on the synapses. This causes an increase of activity on the cellular level. As a result, the imbalance can lead to hyperactivity in the dorsal cochlear nucleus, inferior colliculus, and in the auditory cortex and, later on, to changes in cortical plasticity leading to tinnitus.
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Affiliation(s)
- B Mazurek
- HNO-Klinik und Poliklinik, Tinnituszentrum und molekularbiologisches Forschungslabor, Charité - Universitätsmedizin Berlin, Campus Charité Mitte, Charitéplatz 1, 10117 Berlin.
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225
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Abstract
It is widely acknowledged that neural stem cells generate new neurons through the process of neurogenesis in the adult brain. In mammals, adult neurogenesis occurs in two areas of the CNS: the subventricular zone and the subgranular zone of the dentate gyrus of the hippocampus. The newly generated cells display neuronal morphology, generate action potentials and receive functional synaptic inputs, their properties being equivalent to those of mature neurons. Alzheimer's disease (AD) is the widespread cause of dementia, and is an age-related, progressive and irreversible neurodegenerative disease that results in massive neuronal death and deterioration of cognitive functions. Here, we overview the relations between adult neurogenesis and AD, and try to analyse the controversies in the field. We also summarise recent data obtained in the triple transgenic model of AD that show time- and region-specific impairment of neurogenesis, which may account for the early changes in synaptic plasticity and cognitive impairments that develop prior to gross neurodegenerative alterations and that could underlie new rescue therapies.
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226
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MacMillan KS, Naidoo J, Liang J, Melito L, Williams NS, Morlock L, Huntington PJ, Estill SJ, Longgood J, Becker GL, McKnight SL, Pieper AA, De Brabander JK, Ready JM. Development of proneurogenic, neuroprotective small molecules. J Am Chem Soc 2011; 133:1428-37. [PMID: 21210688 PMCID: PMC3033481 DOI: 10.1021/ja108211m] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Degeneration of the hippocampus is associated with Alzheimer's disease and occurs very early in the progression of the disease. Current options for treating the cognitive symptoms associated with Alzheimer's are inadequate, giving urgency to the search for novel therapeutic strategies. Pharmacologic agents that safely enhance hippocampal neurogenesis may provide new therapeutic approaches. We discovered the first synthetic molecule, named P7C3, which protects newborn neurons from apoptotic cell death, and thus promotes neurogenesis in mice and rats in the subgranular zone of the hippocampal dentate gyrus, the site of normal neurogenesis in adult mammals. We describe the results of a medicinal chemistry campaign to optimize the potency, toxicity profile, and stability of P7C3. Systematic variation of nearly every position of the lead compound revealed elements conducive toward increases in activity and regions subject to modification. We have discovered compounds that are orally available, nontoxic, stable in mice, rats, and cell culture, and capable of penetrating the blood-brain barrier. The most potent compounds are active at nanomolar concentrations. Finally, we have identified derivatives that may facilitate mode-of-action studies through affinity chromatography or photo-cross-linking.
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Affiliation(s)
- Karen S MacMillan
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9038, United States
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227
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van Gaal S, Scholte HS, Lamme VAF, Fahrenfort JJ, Ridderinkhof KR. Pre-SMA Gray-matter Density Predicts Individual Differences in Action Selection in the Face of Conscious and Unconscious Response Conflict. J Cogn Neurosci 2011; 23:382-90. [DOI: 10.1162/jocn.2010.21444] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Abstract
The presupplementary motor area (pre-SMA) is considered key in contributing to voluntary action selection during response conflict. Here we test whether individual differences in the ability to select appropriate actions in the face of strong (conscious) and weak (virtually unconscious) distracting alternatives are related to individual variability in pre-SMA anatomy. To this end, we scanned 58 participants, who performed a masked priming task in which conflicting response tendencies were elicited either consciously (through primes that were weakly masked) or virtually unconsciously (strongly masked primes), with structural magnetic resonance imaging. Voxel-based morphometry revealed that individual differences in pre-SMA gray-matter density are related to subjects' ability to voluntary select the correct action in the face of conflict, irrespective of the awareness level of conflict-inducing stimuli. These results link structural anatomy to individual differences in cognitive control ability, and provide support for the role of the pre-SMA in the selection of appropriate actions in situations of response conflict. Furthermore, these results suggest that flexible and voluntary behavior requires efficiently dealing with competing response tendencies, even those that are activated automatically and unconsciously.
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228
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Dalvi PS, Nazarians-Armavil A, Tung S, Belsham DD. Immortalized neurons for the study of hypothalamic function. Am J Physiol Regul Integr Comp Physiol 2011; 300:R1030-52. [PMID: 21248304 DOI: 10.1152/ajpregu.00649.2010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The hypothalamus is a vital part of the central nervous system: it harbors control systems implicated in regulation of a wide range of homeostatic processes, including energy balance and reproduction. Structurally, the hypothalamus is a complex neuroendocrine tissue composed of a multitude of unique neuronal cell types that express a number of neuromodulators, including hormones, classical neurotransmitters, and specific neuropeptides that play a critical role in mediating hypothalamic function. However, neuropeptide and receptor gene expression, second messenger activation, and electrophysiological and secretory properties of these hypothalamic neurons are not yet fully defined, primarily because the heterogeneity and complex neuronal architecture of the neuroendocrine hypothalamus make such studies challenging to perform in vivo. To circumvent this problem, our research group recently generated embryonic- and adult-derived hypothalamic neuronal cell models by utilizing the novel molecular techniques of ciliary neurotrophic factor-induced neurogenesis and SV40 T antigen transfer to primary hypothalamic neuronal cell cultures. Significant research with these cell lines has demonstrated their value as a potential tool for use in molecular genetic analysis of hypothalamic neuronal function. Insights gained from hypothalamic immortalized cells used in conjunction with in vivo models will enhance our understanding of hypothalamic functions such as neurogenesis, neuronal plasticity, glucose sensing, energy homeostasis, circadian rhythms, and reproduction. This review discusses the generation and use of hypothalamic cell models to study mechanisms underlying the function of individual hypothalamic neurons and to gain a more complete understanding of the overall physiology of the hypothalamus.
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Affiliation(s)
- Prasad S Dalvi
- Dept. of Physiology, University of Toronto, 1 Kings College Circle, Toronto, Ontario, Canada
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229
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Majerská J, Sýkorová E, Fajkus J. Non-telomeric activities of telomerase. MOLECULAR BIOSYSTEMS 2011; 7:1013-23. [DOI: 10.1039/c0mb00268b] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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230
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Neural Stem Cells. Regen Med 2011. [DOI: 10.1007/978-90-481-9075-1_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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231
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Fleisch VC, Fraser B, Allison WT. Investigating regeneration and functional integration of CNS neurons: lessons from zebrafish genetics and other fish species. Biochim Biophys Acta Mol Basis Dis 2010; 1812:364-80. [PMID: 21044883 DOI: 10.1016/j.bbadis.2010.10.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Revised: 10/05/2010] [Accepted: 10/21/2010] [Indexed: 12/21/2022]
Abstract
Zebrafish possess a robust, innate CNS regenerative ability. Combined with their genetic tractability and vertebrate CNS architecture, this ability makes zebrafish an attractive model to gain requisite knowledge for clinical CNS regeneration. In treatment of neurological disorders, one can envisage replacing lost neurons through stem cell therapy or through activation of latent stem cells in the CNS. Here we review the evidence that radial glia are a major source of CNS stem cells in zebrafish and thus activation of radial glia is an attractive therapeutic target. We discuss the regenerative potential and the molecular mechanisms thereof, in the zebrafish spinal cord, retina, optic nerve and higher brain centres. We evaluate various cell ablation paradigms developed to induce regeneration, with particular emphasis on the need for (high throughput) indicators that neuronal regeneration has restored sensory or motor function. We also examine the potential confound that regeneration imposes as the community develops zebrafish models of neurodegeneration. We conclude that zebrafish combine several characters that make them a potent resource for testing hypotheses and discovering therapeutic targets in functional CNS regeneration. This article is part of a Special Issue entitled Zebrafish Models of Neurological Diseases.
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Affiliation(s)
- Valerie C Fleisch
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, Alberta, Canada.
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232
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Transplanted bone marrow stem cells relocate to infarct penumbra and co-express endogenous proliferative and immature neuronal markers in a mouse model of ischemic cerebral stroke. BMC Neurosci 2010; 11:138. [PMID: 20973978 PMCID: PMC2974740 DOI: 10.1186/1471-2202-11-138] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 10/25/2010] [Indexed: 12/18/2022] Open
Abstract
Background Several studies demonstrate that neurogenesis may be induced or activated following vascular insults, which may be important for neuronal regeneration and functional recovery. Understanding the cellular mechanism underlying stroke-associated neurogenesis is of neurobiological as well as neurological/clinical relevance. The present study attempted to explore potential homing and early development of transplanted bone marrow stem cells in mouse forebrain after focal occlusion of the middle cerebral artery, an experimental model of ischemic stroke. Results Bone marrow stem cells isolated from donor mice were confirmed by analysis of surface antigen profile, and were pre-labeled with a lipophilic fluorescent dye PKH26, and subsequently transfused into recipient mice with middle cerebral artery coagulation. A large number of PKH26-labeled cells were detected surrounding the infarct site, most of which colocalized with immunolabelings for the proliferating cell nuclear antigen (PCNA) and some also colocalized with the immature neuronal marker doublecortin (DCX) during 1-2 weeks after the bone marrow cells transfusion. Conclusions The present study shows that transplanted bone morrow cells largely relocate to the infarct penumbra in ischemic mouse cerebrum. These transplanted bone marrow cells appear to undergo a process of in situ proliferation and develop into putative cortical interneurons during the early phase of experimental vascular injury.
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233
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Dupret D, Abrous DN. [A new chapter in the field of memory: hippocampal neo-neurogenesis]. Biol Aujourdhui 2010; 204:113-29. [PMID: 20950556 DOI: 10.1051/jbio/2010004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2010] [Indexed: 11/14/2022]
Abstract
The dogma according to which "once the development of the central nervous system ended, generation of neurons was impossible" has been challenged by the discovery that new neurons are created in specific regions of the adult mammalian brain. This discovery has been one of the most controversial of modern neuroscience. One of these regions is the dentate gyrus of the hippocampal formation, a key structure in memory. Here we will review our current knowledge on the role of adult hippocampal neurogenesis in memory and in the pathophysiology of memory. In particular we will review evidence showing that adult-born neurons are required for learning and memory and that an alteration of their production rate leads to memory impairments. We also discuss how neurogenesis is finely shaped by learning for the purpose of mnemonic information processing.
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Affiliation(s)
- David Dupret
- MRC Anatomical Neuropharmacology Unit, Oxford OX1 3TH, UK
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234
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Tanaka Y, Tanaka R, Liu M, Hattori N, Urabe T. Cilostazol attenuates ischemic brain injury and enhances neurogenesis in the subventricular zone of adult mice after transient focal cerebral ischemia. Neuroscience 2010; 171:1367-76. [PMID: 20933581 DOI: 10.1016/j.neuroscience.2010.10.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 09/29/2010] [Accepted: 10/02/2010] [Indexed: 11/30/2022]
Abstract
Evidence suggests that neurogenesis occurs in the adult mammalian brain, and that various stimuli, for example, ischemia/hypoxia, enhance the generation of neural progenitor cells in the subventricular zone (SVZ) and their migration into the olfactory bulb. In a mouse stroke model, focal ischemia results in activation of neural progenitor cells followed by their migration into the ischemic lesion. The present study assessed the in vivo effects of cilostazol, a type 3 phosphodiesterase inhibitor known to activate the cAMP-responsive element binding protein (CREB) signaling, on neurogenesis in the ipsilateral SVZ and peri-infarct area in a mouse model of transient middle cerebral artery occlusion. Mice were divided into sham operated (n=12), vehicle- (n=18) and cilostazol-treated (n=18) groups. Sections stained for 5-bromodeoxyuridine (BrdU) and several neuronal and a glial markers were analyzed at post-ischemia days 1, 3 and 7. Cilostazol reduced brain ischemic volume (P<0.05) and induced earlier recovery of neurologic deficit (P<0.05). Cilostazol significantly increased the density of BrdU-positive newly-formed cells in the SVZ compared with the vehicle group without ischemia. Increased density of doublecortin (DCX)-positive and BrdU/DCX-double positive neural progenitor cells was noted in the ipsilateral SVZ and peri-infarct area at 3 and 7 days after focal ischemia compared with the vehicle group (P<0.05). Cilostazol increased DCX-positive phosphorylated CREB (pCREB)-expressing neural progenitor cells, and increased brain derived neurotrophic factor (BDNF)-expressing astrocytes in the ipsilateral SVZ and peri-infarct area. The results indicated that cilostazol enhanced neural progenitor cell generation in both ipsilateral SVZ and peri-infarct area through CREB-mediated signaling pathway after focal ischemia.
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Affiliation(s)
- Y Tanaka
- Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan
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235
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Lau BWM, Yau SY, So KF. Reproduction: a new venue for studying function of adult neurogenesis? Cell Transplant 2010; 20:21-35. [PMID: 20887675 DOI: 10.3727/096368910x532765] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Adult neurogenesis has been a focus within the past few years because it is a newly recognized form of neuroplasticity that may play significant roles in behaviors and recovery process after disease. Mammalian adult neurogenesis could be found in two brain regions: hippocampus and subventricular zone (SVZ). While it is well established that hippocampal neurogenesis participates in memory formation and anxiety, the physiological function of SVZ neurogenesis is still under intense investigation. Recent studies disclose that SVZ neurogenesis is under regulation of reproductive cues like pheromones. Reciprocally, the newborn neurons may exert their effect on reproductive and maternal behaviors. This review discusses recent understanding of the interrelationship between neurogenesis and reproduction. The studies highlighted in this review illustrate the potential importance of neurogenesis in reproductive function and will provide new insights for the significance of adult neurogenesis.
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Affiliation(s)
- Benson Wui-Man Lau
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, PR China
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236
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Mahapatra A. A small molecule which protects newborn neurons. ACS Chem Neurosci 2010; 1:589. [PMID: 22778848 DOI: 10.1021/cn1000809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 08/27/2010] [Indexed: 11/28/2022] Open
Abstract
New research identifies a small molecule providing a chemical scaffold which might be useful in the design of a new class of neuroprotective drugs.
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237
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Zhao S, Zhou Y, Gross J, Miao P, Qiu L, Wang D, Chen Q, Feng G. Fluorescent labeling of newborn dentate granule cells in GAD67-GFP transgenic mice: a genetic tool for the study of adult neurogenesis. PLoS One 2010; 5. [PMID: 20824075 PMCID: PMC2932690 DOI: 10.1371/journal.pone.0012506] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2009] [Accepted: 06/05/2010] [Indexed: 12/12/2022] Open
Abstract
Neurogenesis in the adult hippocampus is an important form of structural plasticity in the brain. Here we report a line of BAC transgenic mice (GAD67-GFP mice) that selectively and transitorily express GFP in newborn dentate granule cells of the adult hippocampus. These GFP(+) cells show a high degree of colocalization with BrdU-labeled nuclei one week after BrdU injection and express the newborn neuron marker doublecortin and PSA-NCAM. Compared to mature dentate granule cells, these newborn neurons show immature morphological features: dendritic beading, fewer dendritic branches and spines. These GFP(+) newborn neurons also show immature electrophysiological properties: higher input resistance, more depolarized resting membrane potentials, small and non-typical action potentials. The bright labeling of newborn neurons with GFP makes it possible to visualize the details of dendrites, which reach the outer edge of the molecular layer, and their axon (mossy fiber) terminals, which project to the CA3 region where they form synaptic boutons. GFP expression covers the whole developmental stage of newborn neurons, beginning within the first week of cell division and disappearing as newborn neurons mature, about 4 weeks postmitotic. Thus, the GAD67-GFP transgenic mice provide a useful genetic tool for studying the development and regulation of newborn dentate granule cells.
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Affiliation(s)
- Shengli Zhao
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Yang Zhou
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jimmy Gross
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Pei Miao
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Li Qiu
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Dongqing Wang
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Qian Chen
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Guoping Feng
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Pathology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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238
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Yoo DY, Nam Y, Kim W, Yoo KY, Park J, Lee CH, Choi JH, Yoon YS, Kim DW, Won MH, Hwang IK. Effects of Ginkgo biloba extract on promotion of neurogenesis in the hippocampal dentate gyrus in C57BL/6 mice. J Vet Med Sci 2010; 73:71-6. [PMID: 20814173 DOI: 10.1292/jvms.10-0294] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ginkgo biloba leaf extract (Gb) has been known to improve blood flow and preclude the tissue from free radical damage. Effects of Gb were examined by using Ki67, a specific proliferative marker for cellular proliferation, and doublecortin (DCX), a marker for immature neurons, indicating degree of neuroblast differentiation in the hippocampal dentate gyrus (DG) of adult C57BL/6 mice. The mice were fed with Gb at 40 and 100 mg/kg once daily for 28 days. The increase of Ki67- and DCX-immunoreactive cells in the DG was increased in a dose-dependent manner. Especially, the group having 100 mg/kg Gb showed a significant increase of DCX-immunoreactive neuroblasts with well-developed tertiary dendrites. Expression of DCX protein in the Gb groups was also significantly increased upon compared with the vehicle group. The results suggested that repeated intake of Gb would enhance cell proliferation and neuroblast differentiation in the mouse DG.
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Affiliation(s)
- Dae Young Yoo
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul 151–742, South Korea
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239
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Pieper AA, Xie S, Capota E, Estill SJ, Zhong J, Long JM, Becker GL, Huntington P, Goldman SE, Shen CH, Capota M, Britt JK, Kotti T, Ure K, Brat DJ, Williams NS, MacMillan KS, Naidoo J, Melito L, Hsieh J, De Brabander J, Ready JM, McKnight SL. Discovery of a proneurogenic, neuroprotective chemical. Cell 2010; 142:39-51. [PMID: 20603013 DOI: 10.1016/j.cell.2010.06.018] [Citation(s) in RCA: 284] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Revised: 06/04/2010] [Accepted: 06/10/2010] [Indexed: 11/29/2022]
Abstract
An in vivo screen was performed in search of chemicals capable of enhancing neuron formation in the hippocampus of adult mice. Eight of 1000 small molecules tested enhanced neuron formation in the subgranular zone of the dentate gyrus. Among these was an aminopropyl carbazole, designated P7C3, endowed with favorable pharmacological properties. In vivo studies gave evidence that P7C3 exerts its proneurogenic activity by protecting newborn neurons from apoptosis. Mice missing the gene encoding neuronal PAS domain protein 3 (NPAS3) are devoid of hippocampal neurogenesis and display malformation and electrophysiological dysfunction of the dentate gyrus. Prolonged administration of P7C3 to npas3(-/-) mice corrected these deficits by normalizing levels of apoptosis of newborn hippocampal neurons. Prolonged administration of P7C3 to aged rats also enhanced neurogenesis in the dentate gyrus, impeded neuron death, and preserved cognitive capacity as a function of terminal aging. PAPERCLIP:
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Affiliation(s)
- Andrew A Pieper
- Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9152, USA.
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240
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Nasrallah HA, Hopkins T, Pixley SK. Differential effects of antipsychotic and antidepressant drugs on neurogenic regions in rats. Brain Res 2010; 1354:23-9. [PMID: 20682307 DOI: 10.1016/j.brainres.2010.07.075] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 07/13/2010] [Accepted: 07/21/2010] [Indexed: 11/30/2022]
Abstract
Increased neurogenesis in the hippocampus and subventricular zone (SVZ) of the brain of animals has been demonstrated following administration of several psychotropic medications. Such changes are thought to regenerate tissues and contribute to the beneficial effects of the medications. This study sought to determine if another neurogenic tissue, the peripheral olfactory epithelium (OE), might also exhibit changes after treatment with psychotropic medications. Young adult male rats were treated with risperidone and paliperidone, atypical antipsychotic medications; fluoxetine, a selective serotonin reuptake inhibitor (SSRI) antidepressant; and diluent control for 28days via drinking water. Bromodeoxyuridine (BrdU) was injected to label dividing cells and positive cells were quantified in the OE, cortical SVZ, and dentate gyrus (DG) of the hippocampus. In the first of two studies, paliperidone and risperidone treatment (at 1mg/kg/day) resulted in increased numbers over controls of BrdU positive cells in the OE. In the second study, examining OE, SVZ and DG in the same animal, paliperidone, but not risperidone or fluoxetine (0.6 mg/kg/day) resulted in increased cells in the OE and posterior SVZ. However, fluoxetine, but not paliperidone or risperidone treatment increased BrdU positive cells in the DG. These results show that psychotropic drug-induced cell proliferation occurs in the OE and parallels changes in the SVZ but not DG. Thus, the peripheral OE can serve as a proxy for certain psychotropic drug-induced actions on SVZ brain cell proliferation. This olfactory model can be employed in human research as a method to explore the neurogenesis effects of various pharmacologic treatments of neuropsychiatric disorders.
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Affiliation(s)
- Henry A Nasrallah
- Dept of Psychiatry, Univ of Cincinnati College of Medicine, Cincinnati, OH 45267-0521, USA
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241
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Haliti N, Islami H, Elezi N, Shabani R, Abdullahu B, Dragusha G. In vitro research of the alteration of neurons in vagal core in medulla oblongata at asphyxic deaths. Bosn J Basic Med Sci 2010; 10:251-9. [PMID: 20846134 PMCID: PMC5504504 DOI: 10.17305/bjbms.2010.2695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The aim of this study was to research the morphological changes of neurons in the vagus nerve nuclei in medulla oblongata in asphyxia related death cases. Morphological changes that were investigated were mainly in the dorsal motor respiratory center (DMRC), nucleus tractus solitarius (nTS) and nucleus ambigus (nA) in the medulla oblongata. In our research, the autopsy material from asphyxia related death cases was used from various etiologies: monoxide carbon (CO), liquid drowning, strangulation, electricity, clinical-pathological death, firing weapon, explosive weapon, sharp and blunt objects and death cases due to accident. The material selected for research was taken from medulla oblongata and lungs from all lobes. The material from the medulla oblongata and lungs was fixed in a 10% solution of buffered formalin. Special histochemical methods for central nervous system (CNS) were employed like: Cresyl echt violet, toluidin blue, Sevier-Munger modification and Grimelius. For stereometrical analysis of the quantitative density of the neurons the universal testing system Weibel M42 was used. The acquired results show that in sudden asphyxia related death cases, there are alterations in the nuclei of vagal nerve in form of: central chromatolysis, axonal retraction, axonal fragmentation, intranuclear vacuolization, cytoplasmic vacuolization, edema, condensation and dispersion of substance of Nissl, proliferation of oligodendrocytes, astrocytes and microglia. The altered population of vagus nerve neurons does not show an important statistical significance compared to the overall quantity of the neurons in the nuclei of the vagus nerve (p<0.05).
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Affiliation(s)
- Naim Haliti
- Department of Forensic Medicine, Faculty of Medicine, University of Prishtina, Clinical Centre N.N. 10000, Prishtina, Kosovo
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242
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Fukushima T. [Pharmacological properties of T-817MA, a novel neurotrophic agent, for treatment of Alzheimer's disease.]. Nihon Yakurigaku Zasshi 2010; 136:11-4. [PMID: 20628207 DOI: 10.1254/fpj.136.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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243
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Xiong K, Cai Y, Zhang XM, Huang JF, Liu ZY, Fu GM, Feng JC, Clough RW, Patrylo PR, Luo XG, Hu CH, Yan XX. Layer I as a putative neurogenic niche in young adult guinea pig cerebrum. Mol Cell Neurosci 2010; 45:180-91. [PMID: 20599617 DOI: 10.1016/j.mcn.2010.06.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 06/11/2010] [Accepted: 06/14/2010] [Indexed: 01/11/2023] Open
Abstract
A considerable number of cells expressing typical immature neuronal markers including doublecortin (DCX+) are present around layer II in the cerebral cortex of young and adult guinea pigs and other larger mammals, and their origin and biological implication await further characterization. We show here in young adult guinea pigs that these DCX+ cells are accompanied by in situ cell division around the superficial cortical layers mostly in layer I, but they co-express proliferating cell nuclear antigen (PCNA) and an early neuronal fate determining factor, PAX6. A small number of these DCX+ cells also colocalize with BrdU following administration of this mitotic indicator. Cranial X-ray irradiation causes a decline of DCX+ cells around layer II, and novel environmental exploration induces c-Fos expression among these cells in several neocortical areas. Together, these data are compatible with a notion that DCX+ cortical neurons around layer II might derive from proliferable neuronal precursors around layer I in young adult guinea pig cerebrum, and that these cells might be modulated by experience under physiological conditions.
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Affiliation(s)
- Kun Xiong
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan, China
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244
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Doeppner TR, El Aanbouri M, Dietz GPH, Weise J, Schwarting S, Bähr M. Transplantation of TAT-Bcl-xL-transduced neural precursor cells: long-term neuroprotection after stroke. Neurobiol Dis 2010; 40:265-76. [PMID: 20554038 DOI: 10.1016/j.nbd.2010.05.033] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 05/14/2010] [Accepted: 05/30/2010] [Indexed: 01/19/2023] Open
Abstract
Neural precursor cells (NPC) are an interesting tool in experimental stroke research, but their therapeutic potential is limited due to poor long-term survival. We therefore in vitro transduced subventricular zone-(SVZ)-derived NPC with the anti-apoptotic fusion protein TAT-Bcl-x(L) and analyzed NPC survival, differentiation, and post-stroke functional deficits after experimental ischemia in mice. Survival of TAT-Bcl-x(L)-transduced NPC, which were injected at day 7 post-stroke into the ischemic striatum, was significantly increased at 4 weeks after stroke. Increased survival of NPC was associated with reduced infarct injury and decreased post-stroke functional deficits. Animals grafted with TAT-Bcl-x(L)-transduced NPC showed an increased number of immature cells expressing the neuronal marker doublecortin. Since mature neuronal differentiation of NPC was not observed, reduced post-stroke injury cannot be attributed to enhanced neuronal regeneration, but rather to indirect by-stander effects of grafted NPC. In line with this, NPC-mediated neuroprotection of cortical neurons in vitro was associated with increased secretion of growth factors. Thus, in vitro transduction of cultivated NPC with TAT-Bcl-x(L) results in enhanced resistance of transplanted NPC followed by long-term neuroprotection and ameliorated functional deficits after transient focal cerebral ischemia in mice.
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Affiliation(s)
- Thorsten R Doeppner
- Department of Neurology, University of Goettingen Medical School, 37075 Goettingen, Germany.
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245
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Feng KL, Wang SP, Wu YS, Lin PY, Tai MY, Tsai YF. Brief spatial experiences increase granule cell survival in the dentate gyrus of adult rats. Behav Brain Res 2010; 210:143-6. [DOI: 10.1016/j.bbr.2010.02.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Revised: 02/12/2010] [Accepted: 02/19/2010] [Indexed: 10/19/2022]
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246
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Khurshid N, Hameed LS, Mohanasundaram S, Iyengar S. Opioid modulation of cell proliferation in the ventricular zone of adult zebra finches (Taenopygia guttata). FASEB J 2010; 24:3681-95. [PMID: 20495180 DOI: 10.1096/fj.09-146746] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Besides modulating pain, stress, physiological functions, motivation, and reward, the opioid system has been implicated in developmental and adult mammalian neurogenesis and gliogenesis. In adult male songbirds including zebra finches, neurons generated from the ventricular zone (VZ) of the lateral ventricles are incorporated throughout the telencephalon, including the song control nuclei, HVC, and area X. Although the endogenous opioid met-enkephalin is present in neurons adjacent to the VZ and is upregulated in song control regions during singing, it is not known whether the opioid system can modulate adult neurogenesis/gliogenesis in zebra finches. We used quantitative RT-PCR and in situ hybridization to demonstrate that μ- and δ-opioid receptors are expressed by the VZ of adult male zebra finches. Treating cultured VZ cells from male birds with the opioid antagonist naloxone led to an increase in cell proliferation measured by 5-bromo-2-deoxyuridine incorporation, whereas administering met-enkephalin had the opposite effect, compared with saline-treated cultures. Systemically administering naloxone (2.5 mg/kg body wt) to adult male zebra finches for 4 d also led to a significant increase in cell proliferation in the ventral VZ of these birds, compared with saline-treated controls. Our results show that cell proliferation is augmented by naloxone in the VZ adjacent to the anterior commissure, suggesting that the endogenous opioids modulate adult neurogenesis/gliogenesis by inhibiting cell proliferation in songbirds.
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Affiliation(s)
- Nazia Khurshid
- Division of Systems Neuroscience, National Brain Research Centre, Manesar, India
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247
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Mather M. Aging and cognition. WILEY INTERDISCIPLINARY REVIEWS. COGNITIVE SCIENCE 2010; 1:346-362. [PMID: 26271375 DOI: 10.1002/wcs.64] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
As we grow older, we gain knowledge and experience greater emotional balance, but we also experience memory loss and difficulties in learning new associations. Which cognitive abilities decline, remain stable or improve with age depends on the health of the brain and body as well as on what skills are practiced or challenged in everyday life. Recent research provides a growing understanding of the relationship between physical and cognitive changes across the life span and reveals ways to increase mental sharpness and avoid cognitive decline. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Mara Mather
- Davis School of Gerontology and Department of Psychology, University of Southern California, Los Angeles, CA 90089,USA
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248
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Abstract
The benefits of dietary restriction (DR) on health and aging prevention have been well recognized. Recent studies suggest that DR may enhance brain functions including learning and memory, synaptic plasticity, and neurogenesis, all of which are associated with brain health. Under the stress stimulated by DR, a favorable environment is established for facilitating neuronal plasticity, enhancing cognitive function, stimulating neurogenesis and regulating inflammatory response. DR-induced expressions of factors such as heat shock proteins (HSPs), neurotrophic factors, and Sirtuin1 (SIRT1) are responsible for the effect of DR on the brain. Due to the difficulty in practising long-term DR in human, the potential mimics of DR are also discussed.
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Affiliation(s)
- Guang Qiu
- Department of Neurology, Nanfang Hospital, Nanfang Medical University, Guangzhou 510515, China
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249
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Arai K, Lo EH. Astrocytes protect oligodendrocyte precursor cells via MEK/ERK and PI3K/Akt signaling. J Neurosci Res 2010; 88:758-63. [PMID: 19830833 DOI: 10.1002/jnr.22256] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Accumulating evidence suggest that trophic coupling among different cell types in the brain is required to maintain normal CNS function. Here we show that astrocytes secrete soluble factors that can be oligodendrocyte-supportive. Oligodendrocyte precursor cells (OPCs) and astrocytes were prepared from neonatal rat brain and cultured separately. We conducted cell culture medium-transfer experiments to examine whether astrocytes secrete OPC-protective factors. Conditioned media from astrocytes protected OPCs against H(2)O(2)-induced oxidative stress, starvation, and oxygen-glucose deprivation. This protective effect may be mediated in part via ERK and Akt signaling pathways. Astrocyte-conditioned media upregulated the phosphorylation levels of ERK and Akt in OPC cultures. Blockade of ERK or Akt signaling with U0126 or LY294002 cancelled the OPC-protective effects of astrocyte-conditioned media. Taken together, these data suggest that astrocytes are an important source for oligodendrocyte-supportive factors. Coupling between these two major glial components in brain may be vital for sustaining white matter homeostasis.
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Affiliation(s)
- Ken Arai
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.
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250
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Giussani C, Roux FE, Ojemann J, Sganzerla EP, Pirillo D, Papagno C. Is preoperative functional magnetic resonance imaging reliable for language areas mapping in brain tumor surgery? Review of language functional magnetic resonance imaging and direct cortical stimulation correlation studies. Neurosurgery 2010; 66:113-20. [PMID: 19935438 DOI: 10.1227/01.neu.0000360392.15450.c9] [Citation(s) in RCA: 295] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE Language functional magnetic resonance imaging (fMRI) has been used extensively in the past decade for both clinical and research purposes. Its integration in the preoperative imaging assessment of brain lesions involving eloquent areas is progressively more diffused in neurosurgical practice. Nevertheless, the reliability of language fMRI is unclear. To understand the reliability of preoperative language fMRI in patients operated on for brain tumors, the surgical studies that compared language fMRI with direct cortical stimulation (DCS) were reviewed. METHODS Articles comparing language fMRI with DCS of language areas were reviewed with attention to the lesion pathology, the magnetic field, the language tasks used pre- and intraoperatively, and the validation modalities adopted to establish the reliability of language fMRI. We tried to explore the effectiveness of language fMRI in gliomas. RESULTS Nine language brain mapping studies compared the findings of fMRI with those of DCS. The studies are not homogeneous for tumor types, magnetic fields, pre- and intraoperative language tasks, intraoperative matching criteria, and results. Sensitivity and specificity were calculated in 5 studies (respectively ranging from 59% to 100% and from 0% to 97%). CONCLUSION The contradictory results of these studies do not allow consideration of language fMRI as an alternative tool to DCS in brain lesions located in language areas, especially in gliomas because of the pattern of growth of these tumors. However, language fMRI conducted with high magnet fields is a promising brain mapping tool that must be validated by DCS in methodological robust studies.
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Affiliation(s)
- Carlo Giussani
- Clinica Neurochirurgica, Dip. di Neuroscienze e Tecnologie Biomediche, Università degli Studi di Milano-Bicocca, Ospedale San Gerardo dei Tintori, via Pergolesi 33, Monza, Italy.
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