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Fitzner D, Schneider A, Kippert A, Möbius W, Willig KI, Hell SW, Bunt G, Gaus K, Simons M. Myelin basic protein-dependent plasma membrane reorganization in the formation of myelin. EMBO J 2006; 25:5037-48. [PMID: 17036049 PMCID: PMC1630406 DOI: 10.1038/sj.emboj.7601376] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Accepted: 09/11/2006] [Indexed: 11/09/2022] Open
Abstract
During vertebrate development, oligodendrocytes wrap their plasma membrane around axons to produce myelin, a specialized membrane highly enriched in galactosylceramide (GalC) and cholesterol. Here, we studied the formation of myelin membrane sheets in a neuron-glia co-culture system. We applied different microscopy techniques to visualize lipid packing and dynamics in the oligodendroglial plasma membrane. We used the fluorescent dye Laurdan to examine the lipid order with two-photon microscopy and observed that neurons induce a dramatic lipid condensation of the oligodendroglial membrane. On a nanoscale resolution, using stimulated emission depletion and fluorescence resonance energy transfer microscopy, we demonstrated a neuronal-dependent clustering of GalC in oligodendrocytes. Most importantly these changes in lipid organization of the oligodendroglial plasma membrane were not observed in shiverer mice that do not express the myelin basic protein. Our data demonstrate that neurons induce the condensation of the myelin-forming bilayer in oligodendrocytes and that MBP is involved in this process of plasma membrane rearrangement. We propose that this mechanism is essential for myelin to perform its insulating function during nerve conduction.
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Affiliation(s)
- Dirk Fitzner
- Centre for Biochemistry and Molecular Cell Biology, University of Göttingen, Göttingen, Germany
- Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Anja Schneider
- Centre for Biochemistry and Molecular Cell Biology, University of Göttingen, Göttingen, Germany
- Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Angelika Kippert
- Centre for Biochemistry and Molecular Cell Biology, University of Göttingen, Göttingen, Germany
- Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Wiebke Möbius
- Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Katrin I Willig
- Department of NanoBiophotonics, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Stefan W Hell
- Department of NanoBiophotonics, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Gertrude Bunt
- Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Katharina Gaus
- Centre for Vascular Research at the School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Mikael Simons
- Centre for Biochemistry and Molecular Cell Biology, University of Göttingen, Göttingen, Germany
- Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
- Centre for Biochemistry and Molecular Cell Biology, Max-Planck Institute for Experimental Medicine, University of Göttingen, Hermann Rein Str. 3, 37073 Göttingen, Germany. Tel.: +49 551 3899533; Fax: +49 551 3899201; E-mail:
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52
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Haber M, Zhou L, Murai KK. Cooperative astrocyte and dendritic spine dynamics at hippocampal excitatory synapses. J Neurosci 2006; 26:8881-91. [PMID: 16943543 PMCID: PMC6675342 DOI: 10.1523/jneurosci.1302-06.2006] [Citation(s) in RCA: 302] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Accumulating evidence is redefining the importance of neuron-glial interactions at synapses in the CNS. Astrocytes form "tripartite" complexes with presynaptic and postsynaptic structures and regulate synaptic transmission and plasticity. Despite our understanding of the importance of neuron-glial relationships in physiological contexts, little is known about the structural interplay between astrocytes and synapses. In the past, this has been difficult to explore because studies have been hampered by the lack of a system that preserves complex neuron-glial relationships observed in the brain. Here we present a system that can be used to characterize the intricate relationship between astrocytic processes and synaptic structures in situ using organotypic hippocampal slices, a preparation that retains the three-dimensional architecture of astrocyte-synapse interactions. Using time-lapse confocal imaging, we demonstrate that astrocytes can rapidly extend and retract fine processes to engage and disengage from motile postsynaptic dendritic spines. Surprisingly, astrocytic motility is, on average, higher than its dendritic spine counterparts and likely relies on actin-based cytoskeletal reorganization. Changes in astrocytic processes are typically coordinated with changes in spines, and astrocyte-spine interactions are stabilized at larger spines. Our results suggest that dynamic structural changes in astrocytes help control the degree of neuron-glial communication at hippocampal synapses.
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Affiliation(s)
- Michael Haber
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, H3G 1A4, Canada
| | - Lei Zhou
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, H3G 1A4, Canada
| | - Keith K. Murai
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, H3G 1A4, Canada
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53
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Vähä-Koskela MJV, Kallio JP, Jansson LC, Heikkilä JE, Zakhartchenko VA, Kallajoki MA, Kähäri VM, Hinkkanen AE. Oncolytic capacity of attenuated replicative semliki forest virus in human melanoma xenografts in severe combined immunodeficient mice. Cancer Res 2006; 66:7185-94. [PMID: 16849565 DOI: 10.1158/0008-5472.can-05-2214] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Oncolytic viruses have gained attention as a novel form of cancer treatment. Many viral vectors in use today have been rendered safe by deletion of genes encoding viral structural proteins, thus making them unable to spread beyond the first infected cells. Hence, such replication-deficient constructs may lack efficacy. Here, we analyzed the oncolytic potential of the replication-competent vector VA7-EGFP, based on the avirulent Semliki Forest virus (SFV) strain A7(74), to kill cancer cells in culture as well as to target s.c. human melanoma xenografts in severe combined immunodeficient (SCID) mice. VA7-EGFP was able to infect most cancer cell lines studied, leading to complete lysis of the cells within 72 hours after infection. In SCID mice grafted with A2058 human melanoma, marked regression of the xenografts was observed following a single injection of 10(6) plaque-forming units of virus given either i.p., i.v., or intratumorally. Histologic analysis revealed the presence of virus not only in all treated tumors but also in the brains of the treated mice, causing progressing neuropathology beginning at day 16 after infection. Following initial oncolysis, clusters of viable tumor cells were observed embedded in connective tissue, and at later stages, encapsulated tumor nodules had formed. Infection of melanoma cells from explant cultures of these nodules revealed that a portion of the cells were resistant to virus. To be eligible for use in virotherapy, the ability of avirulent SFV to spread within tumor tissue may have to be improved and the biological safety of the virus may have to be addressed thoroughly in higher animals.
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Affiliation(s)
- Markus J V Vähä-Koskela
- Abo Akademi University, Department of Biochemistry and Pharmacy and Turku Immunology Centre, Turku, Finland.
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54
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Shevtsova Z, Malik JMI, Michel U, Schöll U, Bähr M, Kügler S. Evaluation of epitope tags for protein detection after in vivo CNS gene transfer. Eur J Neurosci 2006; 23:1961-9. [PMID: 16630044 DOI: 10.1111/j.1460-9568.2006.04725.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Functional characterization of disease-related proteins, their splice variants and dominant negative mutants in the context of complex CNS tissues such as brain and retina is frequently assessed by in vivo gene transfer. For correct interpretation of results it is imperative that the protein under investigation is unambiguously detected in the transduced cell types and can be distinguished from any endogenously expressed physiological variants. Therefore the first systematic evaluation of epitope tags used to trace ectopically expressed proteins in the central nervous system is presented here. Substantial differences in the performances of various epitope tag-antibody combinations with respect to sensitivity, specificity and influence of the epitope tag on the fusion protein are elucidated. Epitope tags already established for protein detection in vitro and to some extent in vivo (c-Myc, HA and FLAG tags) were immunohistochemically detected with high sensitivity. However, detection of these tags revealed problems with background staining and we also document structural and functional influence of the tags on the fusion protein. In order to prevent such unwanted side-effects, epitope tags which have not yet been used for in vivo applications (IRS, EE and AU1 tags) were characterized in brain, retina and cultured neurons. While use of the IRS and EE tags was hindered by low sensitivity or specificity, optimal results were obtained with the AU1 epitope, which may develop into a standard tool for detection of ectopic protein expression in the central nervous system.
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Affiliation(s)
- Z Shevtsova
- Department of Neurology; University of Göttingen, Medical School, Waldweg 33, 37073 Göttingen, Germany
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55
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Deng Q, Rashid AJ, Fernandez FR, Turner RW, Maler L, Dunn RJ. A C-terminal domain directs Kv3.3 channels to dendrites. J Neurosci 2006; 25:11531-41. [PMID: 16354911 PMCID: PMC6726014 DOI: 10.1523/jneurosci.3672-05.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Pyramidal neurons of the electrosensory lateral line lobe (ELL) of Apteronotus leptorhynchus express Kv3-type voltage-gated potassium channels that give rise to high-threshold currents at the somatic and dendritic levels. Two members of the Kv3 channel family, AptKv3.1 and AptKv3.3, are coexpressed in these neurons. AptKv3.3 channels are expressed at uniformly high levels in each of four ELL segments, whereas AptKv3.1 channels appear to be expressed in a graded manner with higher levels of expression in segments that process high-frequency electrosensory signals. Immunohistochemical and recombinant channel expression studies show a differential distribution of these two channels in the dendrites of ELL pyramidal neurons. AptKv3.1 is concentrated in somas and proximal dendrites, whereas AptKv3.3 is distributed throughout the full extent of the large dendritic tree. Recombinant channel expression of AptKv3 channels through in vivo viral injections allowed directed retargeting of AptKv3 subtypes over the somadendritic axis, revealing that the sequence responsible for targeting channels to distal dendrites lies within the C-terminal domain of the AptKv3.3 protein. The targeting domain includes a consensus sequence predicted to bind to a PDZ (postsynaptic density-95/Discs large/zona occludens-1)-type protein-protein interaction motif. These findings reveal that different functional roles for Kv3 potassium channels at the somatic and dendritic level of a sensory neuron are attained through specific targeting that selectively distributes Kv3.3 channels to the dendritic compartment.
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Affiliation(s)
- Qingwei Deng
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, McGill University Health Research Institute, Montreal, Quebec, H3G 1A4, Canada
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56
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Abstract
The broad host cell range and high expression levels of transgenes are features that have made alphaviruses attractive for gene expression studies and gene therapy applications. Particularly, Semliki Forest virus vectors have been applied for large-scale production of recombinant membrane proteins for drug screening purposes and structural biology studies. The high preference of expression in neuronal cells has led to many applications of alphavirus vectors in neuroscience. Studies on localization and transport of recombinant proteins as well as electrophysiological recording have become feasible in primary cultures of neurons and hippocampal slice cultures. Alphaviruses have frequently been used as vaccine vectors for expression of antigens against viruses and tumors. Administration of recombinant viral particles, DNA plasmids or in vitro transcribed RNA has resulted in protection against challenges against lethal viruses and tumors in rodent and primate models. Intratumoral injections of alphavirus vectors expressing reporter and immunostimulatory genes have led to significant tumor regression in mouse models. Modifications of the viral envelope structure have generated targeted Sindbis virus vectors. Astonishingly, conventional Sindbis vectors have demonstrated tumor-specific targeting in animal models due to the high density of laminin receptors on cancer cells. Moreover, encaspulation of Semliki Forest virus vectors in liposomes has provided a means of achieving tumor targeting and protection against the host immune response. Much attention has also been given to the engineering of novel mutant alphavirus vectors with properties such as reduced cytotoxicity, prolonged duration of transgene expression and improved survival of host cells.
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Affiliation(s)
- K Lundstrom
- Regulon Inc./BioXtal, Epalinges, Switzerland
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57
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Hassaine G, Wagner R, Kempf J, Cherouati N, Hassaine N, Prual C, André N, Reinhart C, Pattus F, Lundstrom K. Semliki Forest virus vectors for overexpression of 101 G protein-coupled receptors in mammalian host cells. Protein Expr Purif 2006; 45:343-51. [PMID: 16055346 DOI: 10.1016/j.pep.2005.06.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2005] [Revised: 06/06/2005] [Accepted: 06/07/2005] [Indexed: 10/25/2022]
Abstract
Semliki Forest virus vectors were applied for the evaluation of 101 G protein-coupled receptors in three mammalian cell lines. Western blotting demonstrated that 95 of the 101 tested GPCRs showed positive signals. A large number of the GPCRs were expressed at high levels suggesting receptor yields in the range of 1 mg/L or higher, suitable for structural biology applications. Specific binding assays on a selected number of GPCRs were carried out to compare the correlation between total and functional protein expression. Ligands and additives supplemented to the cell culture medium were evaluated for expression enhancement. Selected GPCRs were also expressed from mutant SFV vectors providing enhanced protein expression and reduced host cell toxicity in attempts to further improve receptor yields.
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Affiliation(s)
- Gherici Hassaine
- BioXtal, Chemin des Croisettes 22, CH-1066 Epalinges, Switzerland
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58
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Riezebos-Brilman A, de Mare A, Bungener L, Huckriede A, Wilschut J, Daemen T. Recombinant alphaviruses as vectors for anti-tumour and anti-microbial immunotherapy. J Clin Virol 2006; 35:233-43. [PMID: 16448844 DOI: 10.1016/j.jcv.2005.12.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Accepted: 12/07/2005] [Indexed: 11/15/2022]
Abstract
BACKGROUND Vectors derived from alphaviruses are gaining interest for their high transfection potency and strong immunogenicity. OBJECTIVES After a brief introduction on alphaviruses and their vectors, an overview is given on current preclinical immunotherapy studies using vector systems based on alphaviruses. The efficacy of alphavirus vectors in inducing immune responses will be illustrated by a more detailed description of immunization studies using recombinant Semliki Forest virus for the treatment of human papilloma virus-induced cervical cancer. RESULTS Immunization with recombinant alphavirus results in the induction of humoral and cellular immune responses against microbes, infected cells and cancer cells. Preclinical studies demonstrate that infectious diseases and cancer can be treated prophylactically as well as therapeutically. CONCLUSIONS Alphavirus-based genetic immunization strategies are highly effective in animal model systems, comparing quite favourably with any other approach. Therefore, we hope and expect to see an efficient induction of tumour-or microbial immunity and a positive outcome in future clinical efficacy studies.
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Affiliation(s)
- Annelies Riezebos-Brilman
- Department of Medical Microbiology, Molecular Virology Section, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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59
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Diatta A, Piver E, Collin C, Vaudin P, Pagès JC. Semliki Forest virus-derived virus-like particles: characterization of their production and transduction pathways. J Gen Virol 2006; 86:3129-3136. [PMID: 16227236 DOI: 10.1099/vir.0.81103-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A procedure for the mobilization of Semliki Forest virus (SFV)-derived replicons using virus-like particles (VLPs) has been recently proposed. VLPs were obtained from 293T cells co-expressing the vesicular stomatitis virus glycoprotein (VSV-G) and a modified SFV replicon. Advantages of SFV VLPs include improved safety with a lack of sequence homology between components and reducing the risk of recombination events that could lead to the formation of autonomous particles. Characterization of SFV VLPs reveals a discrepancy in their ability to infect cells reported to be permissive. Furthermore, it was noted that not all viral envelopes were able to promote VLP release equally from transfected cells. These observations encouraged the examination of the molecular mechanisms supporting the different steps of VLP assembly and transduction. The use of a VSV-G related pathway for VLP entry into target cells was demonstrated; it was also observed that an internal ribosome entry site may not be adapted to control transgene expression in all cells. Finally, the need for a membrane-binding domain to obtain a fully active SFV replication complex and VLP formation was documented.
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Affiliation(s)
- A Diatta
- The Vector Group, EA 3856, Faculté de Médecine, 2 Bd Tonnellé, 37000 Tours, France
| | - E Piver
- The Vector Group, EA 3856, Faculté de Médecine, 2 Bd Tonnellé, 37000 Tours, France
| | - C Collin
- Biochemistry, Tours University Hospital, 37000 Tours, France
| | - P Vaudin
- The Vector Group, EA 3856, Faculté de Médecine, 2 Bd Tonnellé, 37000 Tours, France
| | - J-C Pagès
- The Vector Group, EA 3856, Faculté de Médecine, 2 Bd Tonnellé, 37000 Tours, France
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60
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Piver E, Collin C, Diatta A, Vaudin P, Pagès JC. Cellular factors influencing Semliki Forest Virus vector biology. Gene Ther 2005; 12 Suppl 1:S111-7. [PMID: 16231043 DOI: 10.1038/sj.gt.3302625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Viral vectors are currently the best tools for gene delivery in a therapeutic setting, especially for in vivo use. Alphaviruses, a family of positive singlestranded RNA viruses, have been engineered to allow the formation of a highly efficient replicon. Using these replicons, it is possible to generate recombinant particles. Parental viruses and recombinant vectors share certain pathways while interacting with their target cells. In this review, we describe the consecutive events leading to transduction, and transgene expression, in view of the cellular factors that affect each individual step. Classical virology will benefit from the knowledge accumulated studying vectors, and such work will shed light on crosstalk between intruding viruses and their hosts. Ultimately, these data should help the design of vectors adapted to specific target cells.
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Affiliation(s)
- E Piver
- Université François Rabelais, The Vector Group, Faculté de Médecine Tours, France
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61
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Petrakova O, Volkova E, Gorchakov R, Paessler S, Kinney RM, Frolov I. Noncytopathic replication of Venezuelan equine encephalitis virus and eastern equine encephalitis virus replicons in Mammalian cells. J Virol 2005; 79:7597-608. [PMID: 15919912 PMCID: PMC1143662 DOI: 10.1128/jvi.79.12.7597-7608.2005] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Venezuelan equine encephalitis (VEE) and eastern equine encephalitis (EEE) viruses are important, naturally emerging zoonotic viruses. They are significant human and equine pathogens which still pose a serious public health threat. Both VEE and EEE cause chronic infection in mosquitoes and persistent or chronic infection in mosquito-derived cell lines. In contrast, vertebrate hosts infected with either virus develop an acute infection with high-titer viremia and encephalitis, followed by host death or virus clearance by the immune system. Accordingly, EEE and VEE infection in vertebrate cell lines is highly cytopathic. To further understand the pathogenesis of alphaviruses on molecular and cellular levels, we designed EEE- and VEE-based replicons and investigated their replication and their ability to generate cytopathic effect (CPE) and to interfere with other viral infections. VEE and EEE replicons appeared to be less cytopathic than Sindbis virus-based constructs that we designed in our previous research and readily established persistent replication in BHK-21 cells. VEE replicons required additional mutations in the 5' untranslated region and nsP2 or nsP3 genes to further reduce cytopathicity and to become capable of persisting in cells with no defects in alpha/beta interferon production or signaling. The results indicated that alphaviruses strongly differ in virus-host cell interactions, and the ability to cause CPE in tissue culture does not necessarily correlate with pathogenesis and strongly depends on the sequence of viral nonstructural proteins.
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Affiliation(s)
- Olga Petrakova
- Department of Microbiology and Immunology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1019, USA.
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62
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Dreyer J, Schleicher M, Tappe A, Schilling K, Kuner T, Kusumawidijaja G, Müller-Esterl W, Oess S, Kuner R. Nitric oxide synthase (NOS)-interacting protein interacts with neuronal NOS and regulates its distribution and activity. J Neurosci 2005; 24:10454-65. [PMID: 15548660 PMCID: PMC6730309 DOI: 10.1523/jneurosci.2265-04.2004] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Mechanisms governing the activity of neuronal nitric oxide synthase (nNOS), the major source of nitric oxide (NO) in the nervous system, are not completely understood. We report here a protein-protein interaction between nNOS and NOSIP (nitric oxide synthase-interacting protein) in rat brain in vivo. NOSIP and nNOS are concentrated in neuronal synapses and demonstrate significant colocalization in various regions of the central and peripheral nervous systems. NOSIP produces a significant reduction in nNOS activity in a neuroepithelioma cell line stably expressing nNOS. Furthermore, overexpression of NOSIP in cultured primary neurons reduces the availability of nNOS in terminal dendrites. These results thus suggest that the interaction between NOSIP and nNOS is functionally involved in endogenous mechanisms regulating NO synthesis. Furthermore, we found that the subcellular distribution and expression levels of NOSIP are dynamically regulated by neuronal activity in vitro as well as in vivo, suggesting that NOSIP may contribute to a mechanism via which neuronal activity regulates the synaptic availability and activity of nNOS.
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Affiliation(s)
- Jacqueline Dreyer
- Department of Molecular Pharmacology, Pharmacology Institute, University of Heidelberg, 69120 Heidelberg, Germany
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63
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Abstract
The calyx of Held serves as a model for synaptic transmission in the mammalian central nervous system. While offering unique access to the biophysics of presynaptic function, studies addressing the molecular mechanisms of neurotransmitter exocytosis in this model have been mainly limited to pharmacological interventions. To overcome this experimental limitation we used stereotaxic delivery of viral gene shuttles to rapidly and selectively manipulate protein composition in the calyx terminal in vivo. Sindbis or Semliki Forest viruses encoding enhanced green fluorescent protein (EGFP) were injected into the ventral cochlear nucleus (VCN) of rats (postnatal days 7-21) and yielded bright fluorescence in cells of the VCN, including globular bushy cells with their axon and calyx terminal. Fluorescence imaging and three dimensional reconstructions visualized developmental changes in calyx morphology. Small cytoplasmic and synaptic vesicle proteins were successfully overexpressed in the calyx. We extended two-photon microscopy to obtain simultaneous fluorescence and infrared scanning gradient contrast images, allowing for efficient patch-clamp recordings from EGFP-labelled calyces in acute brain slices (postnatal days 9-14). Recordings of spontaneous miniature excitatory postsynaptic currents and short-term depression in synapses overexpressing EGFP or synaptophysin-EGFP revealed normal synaptic function. Thus, Sindbis and Semliki Forest virus-directed overexpression of proteins in the calyx of Held provides a new avenue for molecular structure-function studies of mammalian central synapses.
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Affiliation(s)
- Verena C Wimmer
- Abteilung Zellphysiologie, Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120 Heidelberg, Germany
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64
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Rhême C, Ehrengruber MU, Grandgirard D. Alphaviral cytotoxicity and its implication in vector development. Exp Physiol 2004; 90:45-52. [PMID: 15542620 DOI: 10.1113/expphysiol.2004.028142] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A great variety of viruses have been engineered to serve as expression vectors. Among them, the alphaviruses Semliki Forest virus and Sindbis virus represent promising tools for heterologous gene expression in a wide variety of host cells. Several applications have already been described in neurobiological studies, in gene therapy, for vaccine development and in cancer therapy. Both viruses trigger stress pathways in the cells they infect, sometimes culminating in the death of the host. This inherent property is either an advantage or a drawback, depending on the type of application. This review covers the development and applications of alphavirus vectors and, as our work has been mainly with Semliki Forest virus, we have focused on this virus with special emphasis on how the understanding of Semliki Forest virus cytotoxicity enables it to be manipulated and used.
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Affiliation(s)
- Céline Rhême
- Institute of Molecular Medicine and Cell Research, Albert Ludwigs University, Stephan-Meier Strasse 17, D-79106 Freiburg im Breisgau, Germany.
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65
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Chen H, Honse Y, Ikeda SR. Alternative modalities of adenovirus-mediated gene expression in hippocampal neurons cultured on microisland substrate. Neurosci Lett 2004; 368:221-5. [PMID: 15351453 DOI: 10.1016/j.neulet.2004.07.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Revised: 07/07/2004] [Accepted: 07/11/2004] [Indexed: 11/30/2022]
Abstract
Previously, we have used CsCl gradient-purified recombinant adenovirus (AdV) to successfully transfer genes into hippocampal neurons cultured on microisland substrate. Here, we report that purification of AdV particles is not required and efficient gene expression can be achieved using either crude AdV lysates or HEK 293 cells infected with AdV. The advantages of the simplified procedure are greatly reduced preparation time and reduced requirements for equipment and expertise.
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Affiliation(s)
- Huanmian Chen
- Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Park Bldg. Room 150, 12420 Parklawn Drive, MSC 8115, Bethesda, MD 20892-8815, USA.
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66
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Sato Y, Shiraishi Y, Furuichi T. Cell specificity and efficiency of the Semliki forest virus vector- and adenovirus vector-mediated gene expression in mouse cerebellum. J Neurosci Methods 2004; 137:111-21. [PMID: 15196833 DOI: 10.1016/j.jneumeth.2004.02.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2003] [Revised: 02/06/2004] [Accepted: 02/16/2004] [Indexed: 10/26/2022]
Abstract
Establishing efficient gene transfer and expression in post-mitotic neurons is important in understanding the genetic basis of neural circuits with cellular complexity. This study evaluates the properties of exogenous green fluorescent protein (GFP) expression mediated by the Semliki forest virus (SFV) and adenovirus (Ad) vectors in dissociated and slice cultures of the mouse cerebellum. Infection with SFV-GFP resulted in early-onset and high-level GFP expression in about 90% of Purkinje cells and in about 40% of granule cells in dissociated cultures at 1 day after infection. Two days after infection, GFP-positive cells showed signs of SFV-derived cytotoxicity. Ad-GFP infected almost all astrocytes and granule cells in dissociated cultures, and showed a steady increase in GFP fluorescence with a plateau at around 2 days post-infection. Ad vector-mediated GFP expression lasted for several weeks with no significant cell damage. In the slice cultures, both viral vectors mainly infected astroglial cells, but also showed a similar cell preference as that in dissociated cultures. These data indicate that the use of different viral vectors and infection conditions offers a powerful means of expressing exogenous genes in cerebellar cultures with different cell-type specificity and timing and duration of expression.
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Affiliation(s)
- Yumi Sato
- Laboratory for Molecular Neurogenesis, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
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Kim J, Dittgen T, Nimmerjahn A, Waters J, Pawlak V, Helmchen F, Schlesinger S, Seeburg PH, Osten P. Sindbis vector SINrep(nsP2S726): a tool for rapid heterologous expression with attenuated cytotoxicity in neurons. J Neurosci Methods 2004; 133:81-90. [PMID: 14757348 DOI: 10.1016/j.jneumeth.2003.09.029] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Sindbis virus-based vectors have been successfully used for transient heterologous protein expression in neurons. Their main limitation arises from infection-associated cytotoxicity, attributed largely to a progressive shut down of host cell protein synthesis. Here we evaluated a modified Sindbis vector, based on a viral strain containing a point mutation in the second nonstructural protein, nsP2 P726S, described to delay inhibition of protein synthesis in BHK cells [Virology 228 (1997) 74], for heterologous expression in neurons in vitro and in vivo. First, we constructed an optimized helper vector, termed DH-BB(tRNA/TE12), for production of SINrep(nsP2S(726)) viral particles with low levels of helper RNA co-packaging and high neurospecificity of infection. Second, we determined that hippocampal primary neurons infected with SINrep(nsP2S(726)) virus expressing EGFP showed a delayed onset of viral induced cytotoxicity and higher levels of EGFP expression in comparison to cells infected with wild type SINrep5 EGFP-expressing virus. However, a strong decrease in protein synthesis still occurred by day 3 postinfection. The SINrep(nsP2S(726)) vector is thus well suited for rapid high level expression within this time window. As an experimental example, we demonstrate the applicability of this system for high-resolution two-photon imaging of dendritic spines in vivo.
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Affiliation(s)
- Jinhyun Kim
- Max-Planck Institute for Medical Research, Department of Molecular Neurobiology, Jahnstrasse 29, 69120 Heidelberg, Germany
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Abstract
Alphavirus vectors demonstrate high expression of heterologous proteins in a broad range of host cells. Replication-deficient as well as replication-competent variants exist. Systemic delivery of many viral antigens has elicited strong antibody responses in immunized mice and primates, and protection against challenges with lethal viruses was obtained. Similarly, prophylactic vaccination was established against tumor challenges. Attention has been paid to the engineering of improved targeting to immunologically active cells, such as dendritic cells. In the area of gene therapy, intratumoral injections of alphavirus vectors have resulted in potentially promising tumor rejection. Moreover, encapsulation of alphavirus particles into liposomes demonstrated efficient tumor targeting in mice with severe combined immunodeficiency, which permitted the initiation of clinical trials for patients with advanced kidney carcinoma and melanoma.
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Vähä-Koskela MJV, Tuittila MT, Nygårdas PT, Nyman JKE, Ehrengruber MU, Renggli M, Hinkkanen AE. A novel neurotropic expression vector based on the avirulent A7(74) strain of Semliki Forest virus. J Neurovirol 2003; 9:1-15. [PMID: 12587064 DOI: 10.1080/13550280390173382] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2002] [Revised: 07/17/2002] [Accepted: 09/17/2002] [Indexed: 10/20/2022]
Abstract
Semliki Forest virus (SFV), an enveloped alphavirus of the family Togaviridae, infects a wide range of mammalian host cells. Most strains are neurotropic but differ in virulence. The authors took advantage of the nonpathogenic properties of SFV strain A7(74), cloned recently in their laboratory, and constructed a replication-proficient expression vector to target the central nervous system (CNS) for heterologous gene expression. The vector, termed VA7, was engineered to drive expression of foreign inserts through a second subgenomic promoter inserted in the viral 3' nontranslated region (NTR). Infectious virus was obtained by in vitro transcription and transfection into BHK cells, and was shown to direct synthesis of heterologous proteins in several mammalian cell lines. Although novel expression vehicle is not applicable for targeting specific cell populations within the CNS in its present form, in cultured rat hippocampal slices, VA7 encoding enhanced green fluorescent protein (EGFP) efficiently transduced pyramidal cells, interneurons, and glial cells. With prolonged time post infection, the number of EGFP-expressing neurons in hippocampal slices increased. Mice infected intraperitoneally with the recombinant virus remained completely asymptomatic but showed CNS expression of EGFP as evidenced by immunohistochemistry. SFV A7(74) is a nonintegrating virus, which gives rise to a randomly distributed, patchy infection of the adult CNS that is cleared within 10 days. With the advantage of noninvasive administration, the expression vector described in this work is thus applicable for short-term gene expression in the CNS.
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Ehrengruber MU, Renggli M, Raineteau O, Hennou S, Vähä-Koskela MJV, Hinkkanen AE, Lundstrom K. Semliki Forest virus A7(74) transduces hippocampal neurons and glial cells in a temperature-dependent dual manner. J Neurovirol 2003; 9:16-28. [PMID: 12587065 DOI: 10.1080/13550280390173346] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2002] [Revised: 09/20/2002] [Accepted: 10/04/2002] [Indexed: 01/18/2023]
Abstract
In central nervous system (CNS) tissue preparations, wild-type Semliki Forest virus (SFV) mainly infects neurons, and in vivo it causes lethal encephalitis in neonatal and adult rodents. The SFV strain A7(74), by contrast, is avirulent in adult rodents, triggering only limited CNS infection. To examine A7(74) infection in hippocampal tissue, the authors constructed a replicon, termed SFV(A774nsP)-GFP, expressing green fluorescent protein. The results were compared to replication-proficient recombinant A7(74) encoding GFP, named VA7-EGFP. As nonstructural gene mutations can confer temperature sensitivity, the authors also tested whether infection was temperature-dependent. Indeed, at 31 degrees C both viral recombinants transduced significantly more baby hamster kidney cells than at 37 degrees C. When rat hippocampal slices and dissociated cells were incubated at 37 degrees C, SFV(A774nsP)-GFP transduced glial cells but virtually no neurons-the opposite of conventional SFV. For VA7-EGFP at 37 degrees C, the preferred GFP-positive cells in hippocampal slices were also non-neuronal cells. At 31 degrees C, however, a more wild-type phenotype was found, with 33% and 94% of the GFP-positive cells being neurons for SFV(A774nsP)-GFP in slices and dissociated cells, respectively, and 94% neurons for VA7-EGFP in slices. Immunochemical and electrophysiological analyses confirmed that at 37 degrees C virtually all cells transduced by SFV(A774nsP)-GFP in slices were astrocytes, while at 31 degrees C they also contained neurons. These results show that in addition to the developmental age, the temperature determines which cell type becomes infected by A7(74). Our data suggest that A7(74) is avirulent in adult animals because it does not readily replicate in mature neurons at body temperature, whereas it still does so at lower temperatures.
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71
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Virus-based vectors for gene expression in mammalian cells: Semliki Forest virus. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0167-7306(03)38013-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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