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Kaitainen S, Mähönen AJ, Lappalainen R, Kröger H, J Lammi M, Qu C. TiO
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coating promotes human mesenchymal stem cell proliferation without the loss of their capacity for chondrogenic differentiation. Biofabrication 2013; 5:025009. [DOI: 10.1088/1758-5082/5/2/025009] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Heikura T, Nieminen T, Roschier MM, Karvinen H, Kaikkonen MU, Mähönen AJ, Lesch HP, Rissanen TT, Laitinen OH, Airenne KJ, Ylä-Herttuala S. Baculovirus-mediated vascular endothelial growth factor-D(ΔNΔC) gene transfer induces angiogenesis in rabbit skeletal muscle. J Gene Med 2012; 14:35-43. [PMID: 22162149 DOI: 10.1002/jgm.1637] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Occluded arteries and ischemic tissues cannot always be treated by angioplasty, stenting or by-pass-surgery. Under such circumstances, viral gene therapy may be useful in inducing increased blood supply to ischemic area. There is evidence of improved blood flow in ischemic skeletal muscle and myocardium in both animal and human studies using adenoviral vascular endothelial growth factor (VEGF) gene therapy. However, the expression is transient and repeated gene transfers with the same vector are inefficient due to immune responses. METHODS Different baculoviral vectors pseudotyped with or without vesicular stomatitis virus glycoprotein (VSV-G) and/or carrying woodchuck hepatitis virus post-transcriptional regulatory element (Wpre) were tested both in vitro and in vivo. VEGF-D(ΔNΔC) was used as therapeutic transgene and lacZ as a control. In vivo efficacy was evaluated as capillary enlargement and transgene expression in New Zealand White (NZW) rabbit skeletal muscle. RESULTS A statistically significant capillary enlargement was detected 6 days after gene transfer in transduced areas compared to the control gene transfers with baculovirus and adenovirus encoding β-galactosidase (lacZ). Substantially improved gene transfer efficiency was achieved with a modified baculovirus pseudotyped with VSV-G and carrying Wpre. Dose escalation experiments revealed that either too large volume or too many virus particles caused inflammation and necrosis in the target tissue, whereas 10(9) plaque forming units injected in multiple aliquots resulted in transgene expression with only mild immune reactions. CONCLUSIONS We show the first evidence of biologically significant baculoviral gene transfer in skeletal muscle of NZW rabbits using VEGF-D(ΔNΔC) as a therapeutic transgene.
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Affiliation(s)
- Tommi Heikura
- Department of Biotechnology and Molecular Medicine, AI Virtanen Institute, University of Eastern Finland, Kuopio, Finland
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Abstract
Baculovirus expression vector system (BEVS) is well known as a feasible and safe technology to produce recombinant (re-)proteins in a eukaryotic milieu of insect cells. However, its proven power in gene delivery and gene therapy is still poorly recognized. The basis of BEVS lies in large enveloped DNA viruses derived from insects, the prototype virus being Autographa californica multiple nucleopolyhedrovirus (AcMNPV). Infection of insect cell culture with a virus encoding a desired transgene under powerful baculovirus promoter leads to re-protein production in high quantities. Although the replication of AcMNPV is highly insect specific in nature, it can penetrate and transduce a wide range of cells of other origin. Efficient transduction requires only virus arming with an expression cassette active in the cells under investigation. The inherent safety, ease and speed of virus generation in high quantities, low cytotoxicity and extreme transgene capacity and tropism provides many advantages for gene delivery over the other viral vectors typically derived from human pathogens.
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Affiliation(s)
- Kari J Airenne
- Department of Molecular Medicine, A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland.
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Airenne KJ, Laitinen OH, Mähönen AJ, Ylä-Herttuala S. Transduction of vertebrate cells with recombinant baculovirus. Cold Spring Harb Protoc 2010; 2009:pdb.prot5182. [PMID: 20147117 DOI: 10.1101/pdb.prot5182] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Mähönen AJ, Makkonen KE, Laakkonen JP, Ihalainen TO, Kukkonen SP, Kaikkonen MU, Vihinen-Ranta M, Ylä-Herttuala S, Airenne KJ. Culture medium induced vimentin reorganization associates with enhanced baculovirus-mediated gene delivery. J Biotechnol 2009; 145:111-9. [PMID: 19903502 DOI: 10.1016/j.jbiotec.2009.11.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 09/16/2009] [Accepted: 11/03/2009] [Indexed: 01/04/2023]
Abstract
Baculoviruses can express transgenes under mammalian promoters in a wide range of vertebrate cells. However, the success of transgene expression is dependent on both the appropriate cell type and culture conditions. We studied the mechanism behind the substantial effect of the cell culture medium on efficiency of the baculovirus transduction in different cell lines. We tested six cell culture mediums; the highest transduction efficiency was detected in the presence of RPMI 1640 medium. Vimentin, a major component of type III intermediate filaments, was reorganized in the optimized medium, which associated with enhanced nuclear entry of baculoviruses. Accordingly, the phosphorylation pattern of vimentin was changed in the studied cell lines. These results suggest that vimentin has an important role in baculovirus entry into vertebrate cells. Enhanced gene delivery in the optimized medium was observed also with adenoviruses and lentiviruses. The results highlight the general importance of the culture medium in the assembly of the cytoskeleton network and in viral gene delivery.
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Affiliation(s)
- Anssi J Mähönen
- A.I. Virtanen Institute, Department of Biotechnology and Molecular Medicine, University of Kuopio Kuopio, Finland.
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Kinnunen K, Kalesnykas G, Mähönen AJ, Laidinen S, Holma L, Heikura T, Airenne K, Uusitalo H, Ylä-Herttuala S. Baculovirus is an efficient vector for the transduction of the eye: comparison of baculovirus- and adenovirus-mediated intravitreal vascular endothelial growth factor D gene transfer in the rabbit eye. J Gene Med 2009; 11:382-9. [PMID: 19263462 DOI: 10.1002/jgm.1311] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND The present study aimed to determine the efficiency and safety of baculovirus-mediated intravitreal gene transfer in rabbit eye and to compare its efficiency with adenovirus. We also studied how an intravitreal injection of vectors producing vascular endothelial growth factor D (VEGF-D) impacts the vasculature of rabbit eye. METHODS Baculoviral (BacVEGF-D) or adenoviral VEGF-D (AdVEGF-D) were administered intravitreally into the right eye at different doses (10(8), 10(9) and 10(10) IU/ml) to 24 animals. Left eyes were injected with control viruses. To determine how long transgene expression lasted, we injected BacVEGF-D or BacLacZ to the vitreous humour of 11 animals and followed them for 4 weeks. Vitreous samples were taken after sacrifice for enzyme-linked immunosorbent assays and eyes were removed and fixed for histological analyses. RESULTS Both baculoviruses and adenoviruses caused efficient expression of VEGF-D in the rabbit eyes. BacVEGF-D caused a dose-dependent vascular leakage and a moderate dilation of the capillaries. The highest effect was seen 6 days after gene transfer and was detectable for 2 weeks. Intravitreal injection of baculovirus caused expression of VEGF-D in the inner retina, photoreceptor cells and in retinal pigment epithelium cells, whereas adenovirus-mediated VEGF-D expression was detected in the nerve fiber layer and ganglion cell layer. Baculovirus caused a transient inflammation similar to adenoviruses. CONCLUSIONS The study suggests that baculoviruses are efficient vectors for ocular gene transfer, especially if deeper retinal layers need to be transduced. In addition, intravitreal VEGF-D gene transfer caused blood-retina barrier breakdown but not neovessel formation in the rabbit eye.
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Affiliation(s)
- Kati Kinnunen
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute, University of Kuopio, Kuopio, Finland
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Kärkkäinen HR, Lesch HP, Määttä AI, Toivanen PI, Mähönen AJ, Roschier MM, Airenne KJ, Laitinen OH, Ylä-Herttuala S. A 96-well format for a high-throughput baculovirus generation, fast titering and recombinant protein production in insect and mammalian cells. BMC Res Notes 2009; 2:63. [PMID: 19389242 PMCID: PMC2680411 DOI: 10.1186/1756-0500-2-63] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Accepted: 04/23/2009] [Indexed: 11/10/2022] Open
Abstract
Background Baculovirus expression vector system (BEVS) has become a standard in recombinant protein production and virus-like particle preparation for numerous applications. Findings We describe here protocols which adapt baculovirus generation into 96-well format. Conclusion The established methodology allows simple baculovirus generation, fast virus titering within 18 h and efficient recombinant protein production in a high-throughput format. Furthermore, the produced baculovirus vectors are compatible with gene expression in vertebrate cells in vitro and in vivo.
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Affiliation(s)
- Hanna-Riikka Kärkkäinen
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, Kuopio, Finland.
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Airenne KJ, Laitinen OH, Mähönen AJ, Ylä-Herttuala S. Preparation of recombinant baculoviruses with the BVboost system. Cold Spring Harb Protoc 2009; 2009:pdb.prot5181. [PMID: 20147116 DOI: 10.1101/pdb.prot5181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
INTRODUCTIONWe have developed an improved transposition-based system (BVboost) for the generation of recombinant baculoviruses. This system bypasses the disadvantages of the original transposition-based generation of baculoviral genomes in Escherichia coli while remaining a simple, rapid, and convenient viral production technique. The method is based on the modified donor vector (pBVboost) and an improved selection scheme of the baculoviral genomes (bacmids) in E. coli with a mutated sacB gene. Recombinant bacmids can be generated at a frequency of ~107/μg of donor vector with a negligible background. The BVboost system also allows efficient setups for high-throughput screening and gene expression purposes. After cloning the desired gene/cDNA/library into a BVboost system-compatible donor plasmid, the recombinant baculoviral genome is prepared simply by transforming electrocompetent DH10BacΔTn7 E. coli cells with the donor. Transfer from the donor vector into the baculoviral genome (bacmid) occurs via a Tn7-mediated site-specific transposition reaction in E. coli cells. The selection scheme guarantees that virtually all colonies are correct. The recombinant baculoviral genome is subsequently extracted from E. coli culture using a modified isolation procedure for large plasmids. To generate the recombinant viruses, insect cells are transfected with the isolated recombinant bacmid. This protocol provides instructions on how to prepare recombinant baculoviruses by the BVboost system in order to express the desired gene(s) in insect and/or vertebrate cells.
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Mähönen AJ, Airenne KJ, Purola S, Peltomaa E, Kaikkonen MU, Riekkinen MS, Heikura T, Kinnunen K, Roschier MM, Wirth T, Ylä-Herttuala S. Post-transcriptional regulatory element boosts baculovirus-mediated gene expression in vertebrate cells. J Biotechnol 2007; 131:1-8. [PMID: 17617485 DOI: 10.1016/j.jbiotec.2007.05.022] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2006] [Revised: 05/09/2007] [Accepted: 05/21/2007] [Indexed: 10/23/2022]
Abstract
Baculoviruses can express transgenes in a wide range of vertebrate cells. However, in some cells transgene expression is weak. To enhance transgene expression, we studied the effect of the Woodchuck hepatitis virus post-transcriptional regulatory element (WPRE) on baculovirus (BV)-mediated gene expression of several transgenes. A significant increase in BV-mediated gene expression was detected in several cell lines. A 10-fold increase in transgene expression was observed with the WPRE as determined by the percentage of positive cells and mean fluorescence intensity (MFI). Furthermore, a combination of optimized cell culture medium and WPRE virus led to more than a 60-fold increase in gene expression. In accordance, elevated mRNA and protein levels were detected in WPRE-virus transduced cells. In HepG2 and RaaSMC, WPRE-mediated enhancement was comparable to the previously shown positive effect of sodium butyrate on BV-mediated gene expression. Thus, inclusion of the WPRE into a baculovirus vector provides a simple means to improve BV-mediated gene expression in vertebrate cells.
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Affiliation(s)
- Anssi J Mähönen
- A.I. Virtanen Institute, Department of Biotechnology and Molecular Medicine, Kuopio, Finland
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Leppänen P, Kholová I, Mähönen AJ, Airenne K, Koota S, Mansukoski H, Närväinen J, Wirzenius M, Alhonen L, Jänne J, Alitalo K, Ylä-Herttuala S. Short and long-term effects of hVEGF-A(165) in Cre-activated transgenic mice. PLoS One 2006; 1:e13. [PMID: 17183639 PMCID: PMC1762316 DOI: 10.1371/journal.pone.0000013] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Accepted: 09/02/2006] [Indexed: 11/18/2022] Open
Abstract
We have generated a transgenic mouse where hVEGF-A(165) expression has been silenced with loxP-STOP fragment, and we used this model to study the effects of hVEGF-A(165) over-expression in mice after systemic adenovirus mediated Cre-gene transfer. Unlike previous conventional transgenic models, this model leads to the expression of hVEGF-A(165) in only a low number of cells in the target tissues in adult mice. Levels of hVEGF-A(165) expression were moderate and morphological changes were found mainly in the liver, showing typical signs of active angiogenesis. Most mice were healthy without any major consequences up to 18 months after the activation of hVEGF-A(165) expression. However, one mouse with a high plasma hVEGF-A(165) level died spontaneously because of bleeding into abdominal cavity and having liver hemangioma, haemorrhagic paratubarian cystic lesions and spleen peliosis. Also, two mice developed malignant tumors (hepatocellular carcinoma and lung adenocarcinoma), which were not seen in control mice. We conclude that long-term uncontrolled hVEGF-A(165) expression in only a limited number of target cells in adult mice can be associated with pathological changes, including possible formation of malignant tumors and uncontrolled bleeding in target tissues. These findings have implications for the design of long-term clinical trials using hVEGF-A(165) gene and protein.
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Affiliation(s)
- Pia Leppänen
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute, University of KuopioKuopio, Finland
| | - Ivana Kholová
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute, University of KuopioKuopio, Finland
| | - Anssi J. Mähönen
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute, University of KuopioKuopio, Finland
| | - Kari Airenne
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute, University of KuopioKuopio, Finland
| | - Suvi Koota
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute, University of KuopioKuopio, Finland
| | | | - Johanna Närväinen
- Faculty of Life Sciences, University of ManchesterManchester, United Kingdom
| | - Maria Wirzenius
- Molecular/Cancer Biology Laboratory, Biomedicum, University of HelsinkiHelsinki, Finland
| | - Leena Alhonen
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute, University of KuopioKuopio, Finland
| | - Juhani Jänne
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute, University of KuopioKuopio, Finland
| | - Kari Alitalo
- Molecular/Cancer Biology Laboratory, Biomedicum, University of HelsinkiHelsinki, Finland
| | - Seppo Ylä-Herttuala
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute, University of KuopioKuopio, Finland
- Department of Medicine and the Gene Therapy Unit, Kuopio University HospitalKuopio, Finland
- * To whom correspondence should be addressed. E-mail:
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Laitinen OH, Airenne KJ, Hytönen VP, Peltomaa E, Mähönen AJ, Wirth T, Lind MM, Mäkelä KA, Toivanen PI, Schenkwein D, Heikura T, Nordlund HR, Kulomaa MS, Ylä-Herttuala S. A multipurpose vector system for the screening of libraries in bacteria, insect and mammalian cells and expression in vivo. Nucleic Acids Res 2005; 33:e42. [PMID: 15731335 PMCID: PMC549581 DOI: 10.1093/nar/gni042] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
We have constructed a novel tetra-promoter vector (pBVboostFG) system that enables screening of gene/cDNA libraries for functional genomic studies. The vector enables an all-in-one strategy for gene expression in mammalian, bacterial and insect cells and is also suitable for direct use in vivo. Virus preparation is based on an improved mini Tn7 transpositional system allowing easy and fast production of recombinant baculoviruses with high diversity and negligible background. Cloning of the desired DNA fragments or libraries is based on the recombination system of bacteriophage lambda. As an example of the utility of the vector, genes or cDNAs of 18 different proteins were cloned into pBVboostFG and expressed in different hosts. As a proof-of-principle of using the vector for library screening, a chromophoric Thr65-Tyr-Gly67-stretch of enhanced green fluorescent protein was destroyed and subsequently restored by novel PCR strategy and library screening. The pBVboostFG enables screening of genome-wide libraries, thus making it an efficient new platform technology for functional genomics.
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Affiliation(s)
- Olli H. Laitinen
- Department of Molecular Medicine and Biotechnology, A.I. Virtanen Institute, University of KuopioPO Box 1627 FIN-70211, Kuopio, Finland
| | - Kari J. Airenne
- Department of Molecular Medicine and Biotechnology, A.I. Virtanen Institute, University of KuopioPO Box 1627 FIN-70211, Kuopio, Finland
| | - Vesa P. Hytönen
- Department of Biological and Environmental Science, NanoScience Center University of JyväskyläJyväskylä, Finland
| | - Erik Peltomaa
- Department of Molecular Medicine and Biotechnology, A.I. Virtanen Institute, University of KuopioPO Box 1627 FIN-70211, Kuopio, Finland
| | - Anssi J. Mähönen
- Department of Molecular Medicine and Biotechnology, A.I. Virtanen Institute, University of KuopioPO Box 1627 FIN-70211, Kuopio, Finland
| | - Thomas Wirth
- Department of Molecular Medicine and Biotechnology, A.I. Virtanen Institute, University of KuopioPO Box 1627 FIN-70211, Kuopio, Finland
| | - Miia M. Lind
- Department of Molecular Medicine and Biotechnology, A.I. Virtanen Institute, University of KuopioPO Box 1627 FIN-70211, Kuopio, Finland
| | - Kari A. Mäkelä
- Department of Molecular Medicine and Biotechnology, A.I. Virtanen Institute, University of KuopioPO Box 1627 FIN-70211, Kuopio, Finland
| | - Pyry I. Toivanen
- Department of Molecular Medicine and Biotechnology, A.I. Virtanen Institute, University of KuopioPO Box 1627 FIN-70211, Kuopio, Finland
| | - Diana Schenkwein
- Department of Molecular Medicine and Biotechnology, A.I. Virtanen Institute, University of KuopioPO Box 1627 FIN-70211, Kuopio, Finland
| | - Tommi Heikura
- Department of Molecular Medicine and Biotechnology, A.I. Virtanen Institute, University of KuopioPO Box 1627 FIN-70211, Kuopio, Finland
| | - Henri R. Nordlund
- Department of Biological and Environmental Science, NanoScience Center University of JyväskyläJyväskylä, Finland
| | - Markku S. Kulomaa
- Department of Biological and Environmental Science, NanoScience Center University of JyväskyläJyväskylä, Finland
| | - Seppo Ylä-Herttuala
- Department of Molecular Medicine and Biotechnology, A.I. Virtanen Institute, University of KuopioPO Box 1627 FIN-70211, Kuopio, Finland
- Department of Medicine and Gene Therapy Unit, University of KuopioPO Box 1627 FIN-70211, Kuopio, Finland
- To whom correspondence should be addressed. Tel: +358 17 162075; Fax: +358 17 163751;
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Räty JK, Airenne KJ, Marttila AT, Marjomäki V, Hytönen VP, Lehtolainen P, Laitinen OH, Mähönen AJ, Kulomaa MS, Ylä-Herttuala S. Enhanced gene delivery by avidin-displaying baculovirus. Mol Ther 2004; 9:282-91. [PMID: 14759812 DOI: 10.1016/j.ymthe.2003.11.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2003] [Accepted: 11/09/2003] [Indexed: 12/11/2022] Open
Abstract
Flexible alteration of virus surface properties would be beneficial for enhanced and targeted gene delivery. A useful approach could be based on a high-affinity receptor-ligand pair, such as avidin and biotin. In this study, we have constructed an avidin-displaying baculovirus, Baavi. Avidin display was expected to enhance cell transduction due to the high positive charge of avidin in physiological pH and to provide a binding site for covering the virus with desired biotinylated ligands. Successful incorporation of avidin on the virus envelope was detected by immunoblotting and electron microscopy. Multiple biotin-binding sites per virus were detected with fluorescence-correlation spectroscopy and tight biotin binding was observed using an optical biosensor, IAsys. Baavi showed a 5-fold increase in transduction efficiency in rat malignant glioma cells (BT4C) and a 26-fold increase in rabbit aortic smooth muscle (RAASMC) cells compared to wild-type baculovirus. Enhanced transduction was also observed with biotinylated target cells. Biotinylated epidermal growth factor (EGF) enabled specific targeting of the virus with high efficiency to EGF receptor-expressing (SKOV-3) cells. An additional advantage of the avidin display was demonstrated with biotinylated paramagnetic particles, which enabled magnetic targeting. Altogether, we show that avidin display is a rapid and versatile method to improve viral properties for gene delivery.
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Affiliation(s)
- Jani K Räty
- A. I. Virtanen Institute, Department of Biotechnology and Molecular Medicine, University of Kuopio, P.O. Box 1627, FIN-70120 Kuopio, Finland
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Mähönen AJ, Airenne KJ, Lind MM, Lesch HP, Ylä-Herttuala S. Optimized self-excising Cre-expression cassette for mammalian cells. Biochem Biophys Res Commun 2004; 320:366-71. [PMID: 15219836 DOI: 10.1016/j.bbrc.2004.05.175] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Indexed: 11/21/2022]
Abstract
We observed that overexpression of Cre recombinase in 293 T cells has toxic effects and that the chicken beta-actin promoter is active in Escherichia coli, causing expression of Cre in bacteria. This led to significant problems in the cloning of Cre/loxP constructs. Leaky Cre-expression in E. coli, and toxicity of the Cre overexpression in mammalian cells, were solved by constructing a novel silent self-inactivating Cre (SSi-Cre) expression cassette. The SSi-Cre is based on modified loxP sites flanking the Cre/Int/DsRed fusion gene containing a Cre coding sequence interrupted by an intron, which prevents leaky expression of Cre in E. coli. Additionally, this system contains a reporter gene to visualize Cre activity by fluorescent microscopy. The SSi-Cre cassette provides a universal strategy for the generation of Cre/loxP constructs, as well as a solution to the toxicity caused by the overexpression of Cre in target cells. SSi-Cre should thus provide a useful tool for various applications based on the Cre/loxP system.
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Affiliation(s)
- Anssi J Mähönen
- Department of Molecular Medicine and Biotechnology, AI Virtanen Institute, University of Kuopio, Kuopio, Finland
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Kukkonen SP, Airenne KJ, Marjomäki V, Laitinen OH, Lehtolainen P, Kankaanpää P, Mähönen AJ, Räty JK, Nordlund HR, Oker-Blom C, Kulomaa MS, Ylä-Herttuala S. Baculovirus capsid display: a novel tool for transduction imaging. Mol Ther 2004; 8:853-62. [PMID: 14599820 DOI: 10.1016/j.ymthe.2003.07.009] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Baculoviruses are enveloped insect viruses that can carry large quantities of foreign DNA in their genome. Baculoviruses have proved to be very promising gene therapy vectors but little is known about their transduction mechanisms in mammalian cells. We show in this study that Autographa californica multiple nuclear polyhedrosis virus capsid is compatible with the incorporation of desired proteins in large quantities. Fusions can be made to the N-terminus or C-terminus of the major capsid protein vp39 without compromising the viral titer or functionality. As an example of the baculovirus capsid display we show a tracking of the baculovirus transduction in mammalian cells by an enhanced green fluorescent protein (EGFP)-displaying virus. Our confocal and electron microscopy results suggest that the transduction block in mammalian cells is not in the endosomal escape, as previously proposed, but rather in the cytoplasmic transport or nuclear entry of the virus capsid. Our results also suggest that the EGFP-tagged virus can be used for visualization of the virus biodistribution in vivo. Furthermore, capsid-modified baculoviruses hold great promise for the nuclear and subcellular targeting of transgenes and as a novel peptide display system for a variety of eukaryotic applications.
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Affiliation(s)
- Sari P Kukkonen
- A. I. Virtanen Institute, Department of Molecular Medicine and Biotechnology, FIN-70211, Kuopio, Finland
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