101
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Kinsler R, Taylor MM, Flores NM, Leffert JJ, Beech RD. Altered response to antidepressant treatment in FoxG1 heterozygous knockout mice. Synapse 2010; 64:169-71. [PMID: 19852072 DOI: 10.1002/syn.20737] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Evidence from a variety of sources suggests that structural alterations in the brain, including neurogenesis, may play a role in both the pathogenesis of mood disorders and the mechanism of action of antidepressants. Previous studies have implicated both the transforming growth factor-beta (TGF-beta), and the phosphatidyl inositol-3 kinase (PI3K)-Akt pathways in the neurogenesis-promoting and behavioral properties of antidepressants. Forkhead box protein G1 (FoxG1) is a major regulator of both of these pathways, and FoxG1 heterozygous null mice (FoxG1+/-) have previously been reported to have deficits in adult hippocampal neurogenesis and behavioral abnormalities including deficits in contextual fear learning. However the role of FoxG1, if any, in the response to antidepressants has not been previously investigated.To investigate the role of the FoxG1 gene in the behavioral and neurogenic properties of antidepressants, we tested FoxG1+/- mice and littermate controls in two different rodent models of antidepressant action: the tail suspension test and the forced swim test. FoxG1+/- mice showed no response to antidepressants in either of these tests. These results suggest that normal levels of FoxG1 may be required for the behavioral response to antidepressants.
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Affiliation(s)
- Rebecca Kinsler
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06511, USA
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102
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Smad3 deficiency reduces neurogenesis in adult mice. J Mol Neurosci 2010; 41:383-96. [PMID: 20155334 DOI: 10.1007/s12031-010-9329-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Accepted: 01/06/2010] [Indexed: 12/11/2022]
Abstract
Transforming growth factor-beta signaling through Smad3 inhibits cell proliferation in many cell types. As cell proliferation in the brain is an integral part of neurogenesis, we sought to determine the role of Smad3 in adult neurogenesis through examining processes and structures important to neurogenesis in adult Smad3 null mice. We find that there are fewer proliferating cells in neurogenic regions of adult Smad3 null mouse brains and reduced migration of neuronal precursor cells from the subventricular zone to the olfactory bulb. Alterations in astrocyte number and distribution within the rostral migratory stream of Smad3 null mice give rise to a smaller and more disorganized structure that may impact on neuronal precursor cell migration. However, the proportion of proliferating cells that become neurons is similar in wild type and Smad3 null mice. Our results suggest that signaling through Smad3 is needed to maintain the rate of cell division of neuronal precursors in the adult brain and hence the amount of neurogenesis, without altering neuronal cell fate.
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103
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Goldberg JS, Hirschi KK. Diverse roles of the vasculature within the neural stem cell niche. Regen Med 2010; 4:879-97. [PMID: 19903006 DOI: 10.2217/rme.09.61] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
An interdependent relationship between the vascular and nervous systems begins during the earliest stages of development and persists through the mammalian lifespan. Accordingly, the process of adult neurogenesis involves the coordinated response of both systems to maintain a specialized microenvironment (niche) that tips the scale towards maintenance or regeneration, as needed. Understanding the nature and regulation of this balance will provide a foundation on which the potential for molecular- and stem cell-based therapies can be developed to treat prevalent CNS diseases and disorders. The vasculature is cited as a prominent feature within the adult subventricular zone and subgranular zone, known adult neural stem cell niches, helping to retain neural stem and progenitor cell potential. The vascular compartment within the neural stem cell niche has the unique opportunity to not only regulate neural stem and progenitor cells through direct contact with, and paracrine signaling from, endothelial and mural cells that make up blood vessels, but also integrates systemic signals into the local microenvironment via distribution of soluble factors from blood circulation to regulate stem cell niche behavior. Understanding the intricate role that the vasculature plays to influence neural stem cells in the context of niche regulation will help to bridge the gap from bench to bedside for the development of regeneration-based therapies for the CNS.
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Affiliation(s)
- Joshua S Goldberg
- Baylor College of Medicine, Department of Pediatrics & Molecular, Houston, TX 77030, USA
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104
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Mathieu P, Battista D, Depino A, Roca V, Graciarena M, Pitossi F. The more you have, the less you get: the functional role of inflammation on neuronal differentiation of endogenous and transplanted neural stem cells in the adult brain. J Neurochem 2009; 112:1368-85. [PMID: 20028453 DOI: 10.1111/j.1471-4159.2009.06548.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The differentiation of neural stem cells toward a neuronal phenotype is determined by the extracellular and intracellular factors that form the neurogenic niche. In this review, we discuss the available data on the functional role of inflammation and in particular, pro- and anti-inflammatory cytokines, on neuronal differentiation from endogenous and transplanted neural stem/progenitor cells. In addition, we discuss the role of microglial cell activation on these processes and the fact that microglial cell activation is not univocally associated with a pro-inflammatory milieu. We conclude that brain cytokines could be regarded as part of the endogenous neurogenic niche. In addition, we propose that accumulating evidence suggests that pro-inflammatory cytokines have a negative effect on neuronal differentiation, while anti-inflammatory cytokines exert an opposite effect. The clarification of the functional role of cytokines on neuronal differentiation will be relevant not only to better understand adult neurogenesis, but also to envisage complementary treatments to modulate cytokine action that could increase the therapeutic benefit of future progenitor/stem cell-based therapies.
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Affiliation(s)
- Patricia Mathieu
- Institute Leloir Foundation-IIBBA-CONICET, Buenos Aires, Argentina
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105
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Mobley AK, Tchaicha JH, Shin J, Hossain MG, McCarty JH. Beta8 integrin regulates neurogenesis and neurovascular homeostasis in the adult brain. J Cell Sci 2009; 122:1842-51. [PMID: 19461074 DOI: 10.1242/jcs.043257] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Central nervous system (CNS) neurovascular units are multicellular complexes consisting of neural cells, blood vessels and a milieu of extracellular matrix (ECM) proteins. ECM-mediated adhesion and signaling events within neurovascular units probably contribute to proper CNS development and physiology; however, the molecular mechanisms that control these events remain largely undetermined. Previous studies from our group and others showed that ablation of the ECM receptor, alphavbeta8 integrin, in neural progenitor cells (NPCs) of the embryonic mouse brain results in severe developmental neurovascular pathologies and premature death. Here, we have investigated the functions for this integrin in the adult brain by studying mice harboring a homozygous-null beta8 gene mutation generated on an outbred background that permits survival for several months. We show that adult beta8-/- mice display widespread defects in neurovascular unit homeostasis, including increased numbers of intracerebral blood vessels with pronounced perivascular astrogliosis. Furthermore, in neurogenic regions of the adult brain, where NPCs cluster around blood vessels in neurovascular niches, beta8 integrin is essential for normal control of NPC proliferation and survival. Analysis of NPCs cultured ex vivo reveals that the growth and survival defects correlate, in part, with diminished integrin-mediated activation of latent transforming growth factor beta1 (TGFbeta1), which is an ECM protein ligand for alphavbeta8 integrin. Collectively, these data identify essential functions for beta8 integrin in regulating neurovascular unit physiology in the post-natal mouse brain.
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Affiliation(s)
- Aaron K Mobley
- Department of Cancer Biology, University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
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106
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Olah M, Ping G, De Haas AH, Brouwer N, Meerlo P, Van Der Zee EA, Biber K, Boddeke HWGM. Enhanced hippocampal neurogenesis in the absence of microglia T cell interaction and microglia activation in the murine running wheel model. Glia 2009; 57:1046-61. [PMID: 19115394 DOI: 10.1002/glia.20828] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Recently, activated microglia have been shown to be involved in the regulation of several aspects of neurogenesis under certain experimental conditions both in vitro and in vivo. A neurogenesis supportive microglia phenotype has been suggested to arise from the interaction of microglia with homing encephalitogenic T cells. However, a unified hypothesis regarding the exact nature of microglia activity that is supportive of neurogenesis is yet missing from the field. Our aim was to investigate the connection between microglia activity and adult hippocampal neurogenesis under physiological conditions. To address this question we compared the level of microglia activation in the hippocampus of mice, which had access to a running wheel for 10 days and that of sedentary controls. Surprisingly, despite elevated levels of proliferation of neural precursors and survival of newborn neurons in the dentate gyrus microglia remained in a "resting" state morphologically, antigenically, and at the transcriptional level. Moreover, neither T cells nor MHCII expressing microglia were present in the hippocampal brain parenchyma. Though microglia in the dentate gyrus of the runners proliferated at a higher level than in the sedentary controls, this difference was also present in non-neurogenic sites. Therefore, our findings suggest that classical signs of microglia activation and microglia activation arising from interaction with T cells in particular are not a prerequisite for the activity-induced increase in adult hippocampal neurogenesis in C57Bl/6 mice. Thus, our results draw attention on the species and model differences that might exist regarding the regulation of adult hippocampal neurogenesis.
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Affiliation(s)
- Marta Olah
- Department of Medical Physiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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107
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Abstract
Depression constitutes a widespread condition observed in elderly patients. Recently, it was found that several drugs employed in therapies against depression stimulate hippocampal neurogenesis in young rodents and nonhuman primates. As the rate of neurogenesis is dramatically reduced during ageing, we examined the influences of ageing on neurogenic actions of antidepressants. We tested the impact of fluoxetine, a broadly used antidepressant, on hippocampal neurogenesis in mice of three different age groups (100, 200 and over 400 days of age). Proliferation and survival rate of newly generated cells, as well as the percentage of cells that acquired a neuronal phenotype were analyzed in the hippocampus of mice that received fluoxetine daily in a chronic manner. Surprisingly, the action of fluoxetine on neurogenesis was decreasing as a function of age and was only significant in young animals. Hence, fluoxetine increased survival and the frequency of neuronal marker expression in newly generated cells of the hippocampus in the young adult group (that is 100 days of age) only. No significant effects on neurogenesis could be detected in fluoxetine-treated adult and elderly mice (200 and over 400 days of age). The data indicate that the action of fluoxetine on neurogenesis is highly dependent on the age of the treated individual. Although the function of neurogenesis in the clinical manifestation of depression is currently a matter of speculation, this study clearly shows that the therapeutic effects of antidepressants in elderly patients are not mediated by neurogenesis modulation.
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108
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Ramm P, Couillard-Despres S, Plötz S, Rivera FJ, Krampert M, Lehner B, Kremer W, Bogdahn U, Kalbitzer HR, Aigner L. A nuclear magnetic resonance biomarker for neural progenitor cells: is it all neurogenesis? Stem Cells 2009; 27:420-3. [PMID: 18988707 DOI: 10.1634/stemcells.2008-0816] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In vivo visualization of endogenous neural progenitor cells (NPCs) is crucial to advance stem cell research and will be essential to ensure the safety and efficacy of neurogenesis-based therapies. Magnetic resonance spectroscopic imaging (i.e., spatially resolved spectroscopy in vivo) is a highly promising technique by which to investigate endogenous neurogenesis noninvasively. A distinct feature in nuclear magnetic resonance spectra (i.e., a lipid signal at 1.28 ppm) was recently attributed specifically to NPCs in vitro and to neurogenic regions in vivo. Here, we demonstrate that although this 1.28-ppm biomarker is present in NPC cultures, it is not specific for the latter. The 1.28-ppm marker was also evident in mesenchymal stem cells and in non-stem cell lines. Moreover, it was absent in freshly isolated NPCs but appeared under conditions favoring growth arrest or apoptosis; it is initiated by induction of apoptosis and correlates with the appearance of mobile lipid droplets. Thus, although the 1.28-ppm signal cannot be considered as a specific biomarker for NPCs, it might still serve as a sensor for processes that are tightly associated with neurogenesis and NPCs in vivo, such as apoptosis or stem cell quiescence. However, this requires further experimental evidence. The present work clearly urges the identification of additional biomarkers for NPCs and for neurogenesis.
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Affiliation(s)
- Paul Ramm
- Department of Neurology, University of Regensburg, Regensburg, Germany
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109
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Dopamine receptor activation promotes adult neurogenesis in an acute Parkinson model. Exp Neurol 2009; 219:543-52. [PMID: 19619535 DOI: 10.1016/j.expneurol.2009.07.013] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Revised: 07/04/2009] [Accepted: 07/14/2009] [Indexed: 11/20/2022]
Abstract
Cell proliferation of neural progenitors in the subventricular zone (SVZ) of Parkinson disease (PD) patients and animal models is decreased. It was previously demonstrated that the neurotransmitter dopamine modulates cell proliferation in the embryonic brain. The aim of the present study was to analyze whether oral treatment with the dopamine receptor agonist pramipexole (PPX) modulates adult neurogenesis in the SVZ/olfactory bulb system in a dopaminergic lesion model. 6-Hydroxydopamine (6-OHDA) lesioned adult rats received either PPX (1.0 mg/kg) or PBS orally twice daily and bromodeoxyuridine (BrdU, a cell proliferation marker) for 10 days and were perfused immediately after treatment or 4 weeks after PPX withdrawal. Stereological analysis revealed a significant augmentation in SVZ proliferation by PPX. Consecutively, enhanced neuronal differentiation and more new neurons were present in the olfactory bulb 4 weeks after PPX withdrawal. In addition, dopaminergic neurogenesis was increased in the olfactory bulb after PPX treatment. Motor activity as assessed by using an open field paradigm was permanently increased even after long term PPX withdrawal. In addition, we demonstrate that D2 and D3 receptors are present on adult rat SVZ-derived neural progenitors in vitro, and PPX specifically increased mRNA levels of epidermal growth factor receptor (EGF-R) and paired box gene 6 (Pax6). Oral PPX treatment selectively increases adult neurogenesis in the SVZ-olfactory bulb system by increasing proliferation and cell survival of newly generated neurons. Analyzing the neurogenic fate decisions mediated by D2/D3 signaling pathways may lead to new avenues to induce neural repair in the adult brain.
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110
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Lamba D, Karl M, Reh T. Neural regeneration and cell replacement: a view from the eye. Cell Stem Cell 2009; 2:538-49. [PMID: 18522847 DOI: 10.1016/j.stem.2008.05.002] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Neuronal degenerations in the retina are leading causes of blindness. Like most other areas of the CNS, the neurons of the mammalian retina are not replaced following degeneration. However, in nonmammalian vertebrates, endogenous repair processes restore neurons very efficiently, even after complete loss of the retina. We describe the phenomenon of retinal regeneration in nonmammalian vertebrates and attempts made in recent years to stimulate similar regenerative processes in the mammalian retina. In addition, we review the various strategies employed to replace lost neurons in the retina and the recent use of stem cell technologies to address problems of retinal repair.
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Affiliation(s)
- Deepak Lamba
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
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111
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Ashwood P, Enstrom A, Krakowiak P, Hertz-Picciotto I, Hansen RL, Croen LA, Ozonoff S, Pessah IN, Van de Water J. Decreased transforming growth factor beta1 in autism: a potential link between immune dysregulation and impairment in clinical behavioral outcomes. J Neuroimmunol 2009; 204:149-53. [PMID: 18762342 DOI: 10.1016/j.jneuroim.2008.07.006] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Revised: 07/02/2008] [Accepted: 07/11/2008] [Indexed: 12/13/2022]
Abstract
Autism spectrum disorders (ASD) are characterized by impairment in social interactions, communication deficits, and restricted repetitive interests and behaviors. There is evidence of both immune dysregulation and autoimmune phenomena in autism. We examined the regulatory cytokine transforming growth factor beta-1 (TGF beta 1) because of its role in controlling immune responses. Plasma levels of active TGF beta 1 were evaluated in 75 children with ASD compared with 68 controls. Children with ASD had significantly lower plasma TGF beta 1 levels compared with typically developing controls (p=0.0017) and compared with children with developmental disabilities other than ASD (p=0.0037), after adjusting for age and gender. In addition, there were significant correlations between psychological measures and TGF beta 1 levels, such that lower TGF beta 1 levels were associated with lower adaptive behaviors and worse behavioral symptoms. The data suggest that immune responses in autism may be inappropriately regulated due to reductions in TGF beta 1. Such immune dysregulation may predispose to the development of possible autoimmune responses and/or adverse neuroimmune interactions during critical windows in development.
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Affiliation(s)
- Paul Ashwood
- Department of Medical Microbiology and Immunology, University of California at Davis, United States.
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112
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Ma M, Ma Y, Yi X, Guo R, Zhu W, Fan X, Xu G, Frey WH, Liu X. Intranasal delivery of transforming growth factor-beta1 in mice after stroke reduces infarct volume and increases neurogenesis in the subventricular zone. BMC Neurosci 2008; 9:117. [PMID: 19077183 PMCID: PMC2637876 DOI: 10.1186/1471-2202-9-117] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2008] [Accepted: 12/10/2008] [Indexed: 02/06/2023] Open
Abstract
Background The effect of neurotrophic factors in enhancing stroke-induced neurogenesis in the adult subventricular zone (SVZ) is limited by their poor blood-brain barrier (BBB) permeability. Intranasal administration is a noninvasive and valid method for delivery of neuropeptides into the brain, to bypass the BBB. We investigated the effect of treatment with intranasal transforming growth factor-β1 (TGF-β1) on neurogenesis in the adult mouse SVZ following focal ischemia. The modified Neurological Severity Scores (NSS) test was used to evaluate neurological function, and infarct volumes were determined from hematoxylin-stained sections. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) labeling was performed at 7 days after middle cerebral artery occlusion (MCAO). Immunohistochemistry was used to detect bromodeoxyuridine (BrdU) and neuron- or glia-specific markers for identifying neurogenesis in the SVZ at 7, 14, 21, 28 days after MCAO. Results Intranasal treatment of TGF-β1 shows significant improvement in neurological function and reduction of infarct volume compared with control animals. TGF-β1 treated mice had significantly less TUNEL-positive cells in the ipsilateral striatum than that in control groups. The number of BrdU-incorporated cells in the SVZ and striatum was significantly increased in the TGF-β1 treated group compared with control animals at each time point. In addition, numbers of BrdU- labeled cells coexpressed with the migrating neuroblast marker doublecortin (DCX) and the mature neuronal marker neuronal nuclei (NeuN) were significantly increased after intranasal delivery of TGF-β1, while only a few BrdU labeled cells co-stained with glial fibrillary acidic protein (GFAP). Conclusion Intranasal administration of TGF-β1 reduces infarct volume, improves functional recovery and enhances neurogenesis in mice after stroke. Intranasal TGF-β1 may have therapeutic potential for cerebrovascular disorders.
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Affiliation(s)
- Minmin Ma
- Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, 305# East Zhongshan Road, Nanjing 21002, Jiangsu Province, PR China.
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113
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Yu J, Zhu H, Ko D, Kindy MS. Motoneuronotrophic factor analog GM6 reduces infarct volume and behavioral deficits following transient ischemia in the mouse. Brain Res 2008; 1238:143-53. [PMID: 18789909 PMCID: PMC3275905 DOI: 10.1016/j.brainres.2008.08.053] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 08/12/2008] [Accepted: 08/12/2008] [Indexed: 11/24/2022]
Abstract
Motoneuronotrophic factor (MNTF) is an endogenous neurotrophin that is highly specific for the human nervous system, and some of the observed effects of MNTF include motoneuron differentiation, maintenance, survival, and reinnervation of target muscles and organs. MNTF is a neuro-signaling molecule that binds to specific receptors. Using In Silico Analysis, one of the active sites of MNTF was identified as an analog of six amino acids (GM6). The effect of chemically synthesized GM6 on ischemic stroke was studied in the middle cerebral artery occlusion (MCAo) mouse model. Mice were subjected to 1 hur of ischemia followed by 24 h of reperfusion. Mice were injected intravenously with a bolus of GM6, at various doses (1 and 5 mg/kg) immediately after the start of reperfusion and examined for changes in physiological parameters, neurological deficits and infarct volume. GM6 was able to penetrate the blood brain barrier, and at both 1 and 5 mg/kg showed a significant protection from infarct damage, which translated to improvement of neurological deficits. Administration of GM6 demonstrated no changes in HR, BP, pO(2), pCO(2), or pH. A significant increase over the control group in CBF after reperfusion was observed with GM6 administration, which helped to mitigate the ischemic effect caused by the blockage of blood flow. The time window of treatment was assessed at various times following cerebral ischemia with GM6 demonstrating a significant protective effect up to 6-12 h post ischemia. In addition, GM6 increased neurogenesis, and decreased apoptosis and inflammation in the mouse brain following cerebral ischemic injury. These data suggest that GM6 is neuroprotective to the brain following IV injection in the mouse model of MCAo.
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Affiliation(s)
- Jin Yu
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425
| | - Hong Zhu
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425
| | - Dorothy Ko
- Genervon Biopharmaceuticals, Montebello, CA
| | - Mark S. Kindy
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425
- Ralph H. Johnson VA Medical Center, Charleston, SC, 29401
- Neurological Testing Service, Inc, Charleston, SC 29425
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114
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Walzlein JH, Synowitz M, Engels B, Markovic DS, Gabrusiewicz K, Nikolaev E, Yoshikawa K, Kaminska B, Kempermann G, Uckert W, Kaczmarek L, Kettenmann H, Glass R. The antitumorigenic response of neural precursors depends on subventricular proliferation and age. Stem Cells 2008; 26:2945-54. [PMID: 18757298 DOI: 10.1634/stemcells.2008-0307] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Glioblastomas, the most aggressive primary brain tumors, occur almost exclusively in adult patients. Neural precursor cells (NPCs) are antitumorigenic in mice, as they can migrate to glioblastomas and induce tumor cell death. Here, we show that the antitumor effect of NPCs is age-dependently controlled by cell proliferation in the subventricular zone (SVZ) and that NPCs accumulating at a glioblastoma are diverted from their normal migratory path to the olfactory bulb. Experimentally induced cortical glioblastomas resulted in decreased subventricular proliferation in adult (postnatal day 90) but not in young (postnatal day 30) mice. Adult mice supplied fewer NPCs to glioblastomas and had larger tumors than young mice. Apart from the difference in proliferation, there was neither a change in cell number and death rate in the SVZ nor a change in angiogenesis and immune cell density in the tumors. The ability to kill glioblastomas was similar in NPCs isolated from young and adult mice. The proliferative response of NPCs to glioblastomas depended on the expression of D-type cyclins. In young mice, NPCs express the cyclins D1 and D2, but the expression of cyclin D1 is lost during aging, and in adult NPCs only cyclin D2 remains. In young and adult cyclin D2-deficient mice we observed a reduced supply of NPCs to glioblastomas and the generation of larger tumors compared with wild-type mice. We conclude that cyclin D1 and D2 are nonredundant for the antitumor response of subventricular NPCs. Loss of a single D-type cyclin results in a smaller pool of proliferating NPCs, lower number of NPCs migrating to the tumor, and reduced antitumor activity. Disclosure of potential conflicts of interest is found at the end of this article.
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Affiliation(s)
- Joo-Hee Walzlein
- Max Delbrück Center for Molecular Medicine, Berlin-Buch, Berlin, Germany
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115
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Chen Z, Palmer TD. Cellular repair of CNS disorders: an immunological perspective. Hum Mol Genet 2008; 17:R84-92. [PMID: 18632702 DOI: 10.1093/hmg/ddn104] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Cellular repair is a promising strategy for treating central nervous system (CNS) disorders. Several strategies have been contemplated including replacement of neurons or glia that have been lost due to injury or disease, use of cellular grafts to modify or augment the functions of remaining neurons and/or use of cellular grafts to protect neural tissue by local delivery of growth or trophic factors. Depending on the specific disease target, there may be one or many cell types that could be considered for therapy. In each case, an additional variable must be considered--the role of the immune system in both the injury process itself and in the response to incoming cells. Cellular transplants can be roughly categorized into autografts, allografts and xenografts. Despite the immunological privilege of the CNS, allografts and xenografts can elicit activation of the innate and adaptive immune system. In this article, we evaluate the various effects that immune cells and signals may have on the survival, proliferation, differentiation and migration/integration of transplanted cells in therapeutic approaches to CNS injury and disease.
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Affiliation(s)
- Zhiguo Chen
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
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116
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Abstract
Whereas, in most brain compartments, neuronal cell renewal during early life is replaced by synaptic plasticity and the potentiation of existing pathways and connections, neurogenesis in the hippocampus occurs throughout adulthood. Neuronal progenitor cells in the dentate gyrus of the hippocampus are thought to be the gatekeepers of memory. Neural progenitor cell proliferation and differentiation depends on their intrinsic properties and local environment and is down-regulated in conditions associated with brain inflammation. Conversely, newly-formed neurones can survive despite chronic inflammation and, moreover, specifically arise within an inflammatory environment. Since the endocannabinoid system controls immune responses via multiple cellular and molecular targets and influences cell proliferation, fate decision and cell survival in the central nervous system, we summarise how neurogenesis might be regulated by brain cannabinoids, either directly or indirectly via the immune system. This review presents clear evidence that the cannabinoid system influences adult neurogenesis. However, there is considerable variability with regard to the strain, model and methods utilised and therefore it is difficult to compare studies investigating the cannabinoid system. As a result, it remains far from clear exactly how endocannabinoids regulate neurogenesis.
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Affiliation(s)
- S A Wolf
- Department of Cell and Neurobiology, Faculty of Medicine, Institute of Anatomy, University of Zurich, Zurich, Switzerland
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117
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Abstract
Postischemic neurogenesis has been identified as a compensatory mechanism to repair the damaged brain after stroke. Several factors are released by the ischemic tissue that are responsible for proliferation, differentiation, and migration of neural stem cells. An understanding of their roles may allow future therapies based on treatment with such factors. Although damaged cells release a variety of factors, some of them are stimulatory whereas some are inhibitory for neurogenesis. It is interesting to note that factors like insulin-like growth factor-I can induce proliferation in the presence of fibroblast growth factor-2 (FGF-2), and promote differentiation in the absence of FGF-2. Meanwhile, factors like transforming growth factor-beta can induce the differentiation of neurons while inhibiting the proliferation of neural stem cells. Therefore, understanding the role of each factor in the process of neurogenesis will help physicians to enhance the endogenous response and improve the clinical outcome after stroke. In this article the authors discuss the role of growth factors and stem cells following stroke.
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Affiliation(s)
- Haviryaji S G Kalluri
- Department of Neurological Surgery, University of Wisconsin, Madison, Wisconsin 53792, USA
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118
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Wu CW, Chen YC, Yu L, Chen HI, Jen CJ, Huang AM, Tsai HJ, Chang YT, Kuo YM. Treadmill exercise counteracts the suppressive effects of peripheral lipopolysaccharide on hippocampal neurogenesis and learning and memory. J Neurochem 2007; 103:2471-81. [DOI: 10.1111/j.1471-4159.2007.04987.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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119
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Aronica E, Boer K, Becker A, Redeker S, Spliet WGM, van Rijen PC, Wittink F, Breit T, Wadman WJ, Lopes da Silva FH, Troost D, Gorter JA. Gene expression profile analysis of epilepsy-associated gangliogliomas. Neuroscience 2007; 151:272-92. [PMID: 18093740 DOI: 10.1016/j.neuroscience.2007.10.036] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 09/20/2007] [Accepted: 10/11/2007] [Indexed: 01/08/2023]
Abstract
Gangliogliomas (GG) constitute the most frequent tumor entity in young patients undergoing surgery for intractable epilepsy. The histological composition of GG, with the presence of dysplastic neurons, corroborates their maldevelopmental origin. However, their histogenesis, the pathogenetic relationship with other developmental lesions, and the molecular alterations underlying the epileptogenicity of these tumors remain largely unknown. We performed gene expression analysis using the Affymetrix Gene Chip System (U133 plus 2.0 array). We used GENMAPP and the Gene Ontology database to identify global trends in gene expression data. Our analysis has identified various interesting genes and processes that are differentially expressed in GG when compared with normal tissue. The immune and inflammatory responses were the most prominent processes expressed in GG. Several genes involved in the complement pathway displayed a high level of expression compared with control expression levels. Higher expression was also observed for genes involved in cell adhesion, extracellular matrix and proliferation processes. We observed differential expression of genes as cyclin D1 and cyclin-dependent kinases, essential for neuronal cell cycle regulation and differentiation. Synaptic transmission, including GABA receptor signaling was an under-expressed process compared with control tissue. These data provide some suggestions for the molecular pathogenesis of GG. Furthermore, they indicate possible targets that may be investigated in order to dissect the mechanisms of epileptogenesis and possibly counteract the epileptogenic process in these developmental lesions.
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Affiliation(s)
- E Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
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Schmidt HD, Duman RS. The role of neurotrophic factors in adult hippocampal neurogenesis, antidepressant treatments and animal models of depressive-like behavior. Behav Pharmacol 2007; 18:391-418. [PMID: 17762509 DOI: 10.1097/fbp.0b013e3282ee2aa8] [Citation(s) in RCA: 493] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Major depressive disorder (MDD) is characterized by structural and neurochemical changes in limbic structures, including the hippocampus, that regulate mood and cognitive functions. Hippocampal atrophy is observed in patients with depression and this effect is blocked or reversed by antidepressant treatments. Brain-derived neurotrophic factor and other neurotrophic/growth factors are decreased in postmortem hippocampal tissue from suicide victims, which suggests that altered trophic support could contribute to the pathophysiology of MDD. Preclinical studies demonstrate that exposure to stress leads to atrophy and cell loss in the hippocampus as well as decreased expression of neurotrophic/growth factors, and that antidepressant administration reverses or blocks the effects of stress. Accumulating evidence suggests that altered neurogenesis in the adult hippocampus mediates the action of antidepressants. Chronic antidepressant administration upregulates neurogenesis in the adult hippocampus and this cellular response is required for the effects of antidepressants in certain animal models of depression. Here, we review cellular (e.g. adult neurogenesis) and behavioral studies that support the neurotrophic/neurogenic hypothesis of depression and antidepressant action. Aberrant regulation of neuronal plasticity, including neurogenesis, in the hippocampus and other limbic nuclei may result in maladaptive changes in neural networks that underlie the pathophysiology of MDD.
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Affiliation(s)
- Heath D Schmidt
- Division of Molecular Psychiatry, Abraham Ribicoff Research Facilities, Department of Psychiatry and Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA
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121
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Aigner L, Bogdahn U. TGF-beta in neural stem cells and in tumors of the central nervous system. Cell Tissue Res 2007; 331:225-41. [PMID: 17710437 DOI: 10.1007/s00441-007-0466-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Accepted: 07/04/2007] [Indexed: 10/22/2022]
Abstract
Mechanisms that regulate neural stem cell activity in the adult brain are tightly coordinated. They provide new neurons and glia in regions associated with high cellular and functional plasticity, after injury, or during neurodegeneration. Because of the proliferative and plastic potential of neural stem cells, they are currently thought to escape their physiological control mechanisms and transform to cancer stem cells. Signals provided by proteins of the transforming growth factor (TGF)-beta family might represent a system by which neural stem cells are controlled under physiological conditions but released from this control after transformation to cancer stem cells. TGF-beta is a multifunctional cytokine involved in various physiological and patho-physiological processes of the brain. It is induced in the adult brain after injury or hypoxia and during neurodegeneration when it modulates and dampens inflammatory responses. After injury, although TGF-beta is neuroprotective, it may limit the self-repair of the brain by inhibiting neural stem cell proliferation. Similar to its effect on neural stem cells, TGF-beta reveals anti-proliferative control on most cell types; however, paradoxically, many brain tumors escape from TGF-beta control. Moreover, brain tumors develop mechanisms that change the anti-proliferative influence of TGF-beta into oncogenic cues, mainly by orchestrating a multitude of TGF-beta-mediated effects upon matrix, migration and invasion, angiogenesis, and, most importantly, immune escape mechanisms. Thus, TGF-beta is involved in tumor progression. This review focuses on TGF-beta and its role in the regulation and control of neural and of brain-cancer stem cells.
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Affiliation(s)
- Ludwig Aigner
- Department of Neurology, University of Regensburg, Universitätsstrasse 84, 93053, Regensburg, Germany.
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122
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Johnson EC, Jia L, Cepurna WO, Doser TA, Morrison JC. Global changes in optic nerve head gene expression after exposure to elevated intraocular pressure in a rat glaucoma model. Invest Ophthalmol Vis Sci 2007; 48:3161-77. [PMID: 17591886 PMCID: PMC1950563 DOI: 10.1167/iovs.06-1282] [Citation(s) in RCA: 196] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE In glaucoma, the optic nerve head (ONH) is the likely site of initial injury and elevated intraocular pressure (IOP) is the best-known risk factor. This study determines global gene expression changes in the pressure-injured ONH. METHODS Unilateral sustained IOP elevation (glaucoma, n = 46) or optic nerve transection (n = 10) was produced in rats. ONHs were removed, and the retrobulbar optic nerves were graded for degeneration. Gene expression in the glaucomatous ONH with extensive injury was compared with that in the fellow ONH (n = 6/group), by using cDNA microarrays. Data from 12 arrays were normalized, significant differences in gene expression determined, and significantly affected gene classes identified. For the remaining ONH, grouped by experimental condition and degree of injury, quantitative reverse transcriptase-PCR (qPCR) and ANOVA were used to compare selected message levels. RESULTS Microarray analysis identified more than 2000 significantly regulated genes. For 225 of these genes, the changes were greater than twofold. The most significantly affected gene classes were cell proliferation, immune response, lysosome, cytoskeleton, extracellular matrix, and ribosome. A 2.7-fold increase in ONH cellularity confirmed glaucoma model cell proliferation. By qPCR, increases in levels of periostin, collagen VI, and transforming growth factor beta1 were linearly correlated to the degree of IOP-induced injury. For cyclinD1, fibulin 2, tenascin C, TIMP1, and aquaporin-4, correlations were significantly nonlinear, displaying maximum change with focal injury. CONCLUSIONS In the ONH, pressure-induced injury results in cell proliferation and dramatically altered gene expression. For specific genes, expression levels were most altered by focal injury, suggesting that further array studies may identify initial, and potentially injurious, altered processes.
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Affiliation(s)
- Elaine C Johnson
- Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Department of Ophthalmology, Oregon Health Sciences University, Portland, Oregon 97201, USA.
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Kohl Z, Kandasamy M, Winner B, Aigner R, Gross C, Couillard-Despres S, Bogdahn U, Aigner L, Winkler J. Physical activity fails to rescue hippocampal neurogenesis deficits in the R6/2 mouse model of Huntington's disease. Brain Res 2007; 1155:24-33. [PMID: 17512917 DOI: 10.1016/j.brainres.2007.04.039] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Revised: 04/04/2007] [Accepted: 04/09/2007] [Indexed: 02/01/2023]
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder linked to a mutation in the huntingtin gene leading to protein aggregation in neurons. The generation of new neurons in neurogenic regions, such as the subventricular zone of the lateral ventricle and the dentate gyrus of the hippocampus, is affected by these aggregation processes. In particular, hippocampal neurogenesis is reduced in the R6/2 transgenic mouse model of HD. Since physical activity stimulates adult hippocampal neurogenesis, we examined whether running is capable to rescue the impaired hippocampal neurogenesis in R6/2 mice. Proliferation of hippocampal cells measured by proliferating cell nuclear antigen (PCNA) marker was reduced in R6/2 animals by 64% compared to wild type mice. Accordingly, newly generated neurons labeled with doublecortin (DCX) were diminished by 60% in the hippocampus of R6/2 mice. Furthermore, the number of newly generated mature neurons was decreased by 76%. Within the hippocampus of wild type animals, a four-week running period resulted in a doubling of PCNA-, DCX-, and bromo-deoxyuridine (BrdU)-labeled cells. However, physical exercise failed to stimulate proliferation and survival of newly generated neurons in R6/2 transgenic mouse model of HD. These findings suggest that mutant huntingtin alters the hippocampal microenvironment thus resulting in an impaired neurogenesis. Importantly, this adverse microenvironment impeded neurogenesis upregulation such as induced by physical exercise. Future studies need to decipher the molecular pathways involved in repressing the generation of new neurons after physical activity in huntingtin transgenic rodents.
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Affiliation(s)
- Zacharias Kohl
- Department of Neurology, University of Regensburg, Universitätsstr 84, Regensburg, Germany
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Winner B, Rockenstein E, Lie DC, Aigner R, Mante M, Bogdahn U, Couillard-Despres S, Masliah E, Winkler J. Mutant alpha-synuclein exacerbates age-related decrease of neurogenesis. Neurobiol Aging 2007; 29:913-25. [PMID: 17275140 PMCID: PMC2896275 DOI: 10.1016/j.neurobiolaging.2006.12.016] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Revised: 12/21/2006] [Accepted: 12/28/2006] [Indexed: 01/05/2023]
Abstract
In Parkinson disease, wild-type alpha-synuclein accumulates during aging, whereas alpha-synuclein mutations lead to an early onset and accelerated course of the disease. The generation of new neurons is decreased in regions of neurogenesis in adult mice overexpressing wild-type human alpha-synuclein. We examined the subventricular zone/olfactory bulb neurogenesis in aged mice expressing either wild-type human or A53T mutant alpha-synuclein. Aging wild-type and mutant alpha-synuclein-expressing animals generated significantly fewer new neurons than their non-transgenic littermates. This decreased neurogenesis was caused by a reduction in cell proliferation within the subventricular zone of mutant alpha-synuclein mice. In contrast, no difference was detected in mice overexpressing the wild-type allele. Also, more TUNEL-positive profiles were detected in the subventricular zone, following mutant alpha-synuclein expression and in the olfactory bulb, following wild-type and mutant alpha-synuclein expression. The impaired neurogenesis in the olfactory bulb of different transgenic alpha-synuclein mice during aging highlights the need to further explore the interplay between olfactory dysfunction and neurogenesis in Parkinson disease.
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Affiliation(s)
- Beate Winner
- Department of Neurology, University of Regensburg, Universitaetsstr. 84, 93053 Regensburg, Germany
| | - Edward Rockenstein
- Department of Neurosciences, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0662, USA
| | - D. Chichung Lie
- GSF-National Research Center for Environment and Health, Institute for Developmental Genetics, Ingolsstaedter Landstrasse 1, 85764 Munich, Neuherberg, Germany
| | - Robert Aigner
- Department of Neurology, University of Regensburg, Universitaetsstr. 84, 93053 Regensburg, Germany
| | - Michael Mante
- Department of Neurosciences, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0662, USA
| | - Ulrich Bogdahn
- Department of Neurology, University of Regensburg, Universitaetsstr. 84, 93053 Regensburg, Germany
| | | | - Eliezer Masliah
- Department of Neurosciences, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0662, USA
| | - Jürgen Winkler
- Department of Neurology, University of Regensburg, Universitaetsstr. 84, 93053 Regensburg, Germany
- Department of Neurosciences, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0662, USA
- Corresponding author at: Department of Neurology, University of Regensburg, Universitaetsstr. 84, D-93053 Regensburg, Germany. Tel.: +49 941 941 3341; fax: +49 941 941 3005. (J. Winkler)
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Okada K, Hashimoto K, Iwata Y, Nakamura K, Tsujii M, Tsuchiya KJ, Sekine Y, Suda S, Suzuki K, Sugihara GI, Matsuzaki H, Sugiyama T, Kawai M, Minabe Y, Takei N, Mori N. Decreased serum levels of transforming growth factor-beta1 in patients with autism. Prog Neuropsychopharmacol Biol Psychiatry 2007; 31:187-90. [PMID: 17030376 DOI: 10.1016/j.pnpbp.2006.08.020] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Revised: 08/18/2006] [Accepted: 08/25/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND The neurobiological basis for autism remains poorly understood. Given the key role of transforming growth factor-beta1 (TGF-beta1) in brain development, we hypothesized that TGF-beta1 plays a role in the pathophysiology of autism. In this study, we studied whether serum levels of TGF-beta1 are altered in patients with autism. METHODS We measured serum levels of TGF-beta1 in 19 male adult patients with autism and 21 age-matched male healthy subjects using enzyme-linked immunosorbent assay (ELISA). RESULTS The serum levels (7.34+/-5.21 ng/mL (mean+/-S.D.)) of TGF-beta1 in the patients with autism were significantly (z=-5.106, p<0.001) lower than those (14.48+/-1.64 ng/mL (mean+/-S.D.)) of normal controls. However, there were no marked or significant correlations between serum TGF-beta1 levels and other clinical variables, including Autism Diagnostic Interview-Revised (ADI-R) scores, Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), aggression, Theory of Mind, and Intellectual Quotient (IQ) in patients. CONCLUSIONS These findings suggest that decreased levels of TGF-beta1 may be implicated in the pathophysiology of autism.
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Affiliation(s)
- Kyoko Okada
- Department of Psychiatry and Neurology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
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Stipursky J, Gomes FCA. TGF-β1/SMAD signaling induces astrocyte fate commitmentin vitro: Implications for radial glia development. Glia 2007; 55:1023-33. [PMID: 17549683 DOI: 10.1002/glia.20522] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Radial glial (RG) cells are specialized type of cell, which functions as neuronal precursors and scaffolding guides to migrating neurons during cerebral cortex development. After neurogenesis and migration are completed, most of RG cells transform into astrocytes. Mechanism and molecules involved in this process are not completely elucidated. We previously demonstrated that neurons activate the promoter of the astrocyte maturation marker GFAP in astrocytes by secretion of transforming growth factor beta 1 (TGF-beta1) in vitro. Here, we studied the role of neurons and TGF-beta1 pathway in RG differentiation. To address this question, we employed cortical progenitor cultures enriched in GLAST/nestin double-labeled cells, markers of RG cells. TGF-beta1 and conditioned medium derived from neuron-astrocyte cocultures (CM) decreased the number of cells expressing the precursor marker nestin and increased that expressing GFAP in cortical progenitor cultures. These events were impaired by addition of neutralizing antibodies against TGF-beta1. Increase in the number of GFAP positive cells was associated with Smads 2/3 nuclear translocation, a hallmark of TGF-beta1 pathway activation. PCR-assays revealed a decrease in the levels of mRNA for the RG marker, BLBP (brain lipid binding protein), due to TGF-beta1 and CM treatment. We further identified TGF-beta1 receptor in cortical progenitor cultures suggesting that these cells might be target for TGF-beta1 during development. Our work provides strong evidence that TGF-beta1 might be a novel factor involved in RG-astrocyte transformation and highlights the role of neuron-glia interaction in this process.
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Affiliation(s)
- Joice Stipursky
- Departamento de Anatomia, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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