201
|
Hess GT, Humphries WH, Fay NC, Payne CK. Cellular binding, motion, and internalization of synthetic gene delivery polymers. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:1583-8. [PMID: 17888530 PMCID: PMC2121221 DOI: 10.1016/j.bbamcr.2007.07.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Revised: 07/09/2007] [Accepted: 07/16/2007] [Indexed: 12/30/2022]
Abstract
Using fluorescence microscopy we have tracked the cellular binding, surface motion, and internalization of polyarginine and polyethylenimine, cationic ligands used for gene and protein delivery. Each ligand was complexed with a quantum dot to provide a photostable probe. Transfection with exogenous DNA was used to relate the observed motion to gene delivery. Cell surface motion was independent of sulfated proteoglycans, but dependent on cholesterol. Cellular internalization required sulfated proteoglycans and cholesterol. These observations suggest that sulfated proteoglycans act as cellular receptors for the cationic ligands, rather than only passive binding sites. Understanding the interaction of polyarginine and polyethylenimine with the plasma membrane may assist in designing more efficient gene delivery systems.
Collapse
Affiliation(s)
- Gaelen T Hess
- Biophysics Program, Harvard University, Cambridge, MA 02138, USA
| | | | | | | |
Collapse
|
202
|
|
203
|
Hoekstra D, Rejman J, Wasungu L, Shi F, Zuhorn I. Gene delivery by cationic lipids: in and out of an endosome. Biochem Soc Trans 2007; 35:68-71. [PMID: 17233603 DOI: 10.1042/bst0350068] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cationic lipids are exploited as vectors ('lipoplexes') for delivering nucleic acids, including genes, into cells for both therapeutic and cell biological purposes. However, to meet therapeutic requirements, their efficacy needs major improvement, and better defining the mechanism of entry in relation to eventual transfection efficiency could be part of such a strategy. Endocytosis is the major pathway of entry, but the relative contribution of distinct endocytic pathways, including clathrin- and caveolae-mediated endocytosis and/or macropinocytosis is as yet poorly defined. Escape of DNA/RNA from endosomal compartments is thought to represent a major obstacle. Evidence is accumulating that non-lamellar phase changes of the lipoplexes, facilitated by intracellular lipids, which allow DNA to dissociate from the vector and destabilize endosomal membranes, are instrumental in plasmid translocation into the cytosol, a prerequisite for nuclear delivery. To further clarify molecular mechanisms and to appreciate and overcome intracellular hurdles in lipoplex-mediated gene delivery, quantification of distinct steps in overall transfection and proper model systems are required.
Collapse
Affiliation(s)
- D Hoekstra
- Department of Cell Biology, Section Membrane Cell Biology, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | | | | | | | | |
Collapse
|
204
|
Swami A, Aggarwal A, Pathak A, Patnaik S, Kumar P, Singh Y, Gupta KC. RETRACTED: Imidazolyl-PEI modified nanoparticles for enhanced gene delivery. Int J Pharm 2007; 335:180-192. [PMID: 17169517 DOI: 10.1016/j.ijpharm.2006.11.033] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 11/01/2006] [Accepted: 11/03/2006] [Indexed: 10/23/2022]
Abstract
The derivatives of polyethylenimine (PEI 25 and 750kDa) were synthesized by partially substituting their amino groups with imidazolyl moieties. The series of imidazolyl-PEIs thus obtained were cross-linked with polyethylene glycol (PEG) to get imidazolyl-PEI-PEG nanoparticles (IPP). The component of hydrophobicity was introduced by grafting the lauryl groups in the maximal substituted IPP nanoparticles (IPPL). The nanoparticles were characterized with respect to DNA interaction, hydrodynamic diameter, zeta potential, in vitro cytotoxicity and transfection efficiency on model cell lines. The IPP and IPPL nanoparticles formed a loose complex with DNA compared to the corresponding native PEI, leading to more efficient unpackaging of DNA. The DNA loading capacity of IPP and IPPL nanoparticles was also lower compared to PEI. The imidazolyl substitution improved the gene delivery efficiency of PEI (750kDa) by nine- to ten-fold and PEI (25kDa) by three- to four-fold. At maximum transfection efficiency, the zeta potential of nanoparticles was positive after forming a complex with DNA. The maximum level of reporter gene expression was mediated by IPPL nanoparticles in both the series. The cytotoxicity, another pertinent problem with cationic polymers, was also negligible in case of IPP and IPPL nanoparticles.
Collapse
Affiliation(s)
- Archana Swami
- Institute of Genomics and Integrative Biology, Mall Road, Delhi University Campus, Delhi 110007, India
| | - Anita Aggarwal
- Institute of Genomics and Integrative Biology, Mall Road, Delhi University Campus, Delhi 110007, India
| | - Atul Pathak
- Institute of Genomics and Integrative Biology, Mall Road, Delhi University Campus, Delhi 110007, India
| | - Soma Patnaik
- Institute of Genomics and Integrative Biology, Mall Road, Delhi University Campus, Delhi 110007, India
| | - P Kumar
- Institute of Genomics and Integrative Biology, Mall Road, Delhi University Campus, Delhi 110007, India
| | - Y Singh
- Institute of Genomics and Integrative Biology, Mall Road, Delhi University Campus, Delhi 110007, India
| | - K C Gupta
- Institute of Genomics and Integrative Biology, Mall Road, Delhi University Campus, Delhi 110007, India.
| |
Collapse
|
205
|
van der Aa MAEM, Huth US, Häfele SY, Schubert R, Oosting RS, Mastrobattista E, Hennink WE, Peschka-Süss R, Koning GA, Crommelin DJA. Cellular uptake of cationic polymer-DNA complexes via caveolae plays a pivotal role in gene transfection in COS-7 cells. Pharm Res 2007; 24:1590-8. [PMID: 17385010 PMCID: PMC1915651 DOI: 10.1007/s11095-007-9287-3] [Citation(s) in RCA: 198] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Accepted: 02/27/2007] [Indexed: 12/18/2022]
Abstract
PURPOSE Knowledge about the uptake mechanism and subsequent intracellular routing of non-viral gene delivery systems is important for the development of more efficient carriers. In this study we compared two established cationic polymers pDMAEMA and PEI with regard to their transfection efficiency and mechanism of cellular uptake. MATERIALS AND METHODS The effects of several inhibitors of particular cellular uptake routes on the uptake of polyplexes and subsequent gene expression in COS-7 cells were investigated using FACS and transfection. Moreover, cellular localization of fluorescently labeled polyplexes was assessed by spectral fluorescence microscopy. RESULTS Both pDMAEMA- and PEI-complexed DNA showed colocalization with fluorescently-labeled transferrin and cholera toxin after internalization by COS-7 cells, which indicates uptake via the clathrin- and caveolae-dependent pathways. Blocking either routes of uptake with specific inhibitors only resulted in a marginal decrease in polyplex uptake, which may suggest that uptake routes of polyplexes are interchangeable. Despite the marginal effect of inhibitors on polyplex internalization, blocking the caveolae-mediated uptake route resulted in an almost complete loss of polyplex-mediated gene expression, whereas gene expression was not negatively affected by blocking the clathrin-dependent route of uptake. CONCLUSIONS These results show the importance of caveolae-mediated uptake for successful gene expression and have implications for the rational design of non-viral gene delivery systems.
Collapse
Affiliation(s)
- M. A. E. M. van der Aa
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands
| | - U. S. Huth
- Department of Pharmaceutical Technology and Biopharmacy, Albert-Ludwigs University, Stefan-Meier-Str. 19, D-79104 Freiburg, Germany
| | - S. Y. Häfele
- Department of Pharmaceutical Technology and Biopharmacy, Albert-Ludwigs University, Stefan-Meier-Str. 19, D-79104 Freiburg, Germany
| | - R. Schubert
- Department of Pharmaceutical Technology and Biopharmacy, Albert-Ludwigs University, Stefan-Meier-Str. 19, D-79104 Freiburg, Germany
| | - R. S. Oosting
- Department of Psychopharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands
| | - E. Mastrobattista
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands
| | - W. E. Hennink
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands
| | - R. Peschka-Süss
- Department of Pharmaceutical Technology and Biopharmacy, Albert-Ludwigs University, Stefan-Meier-Str. 19, D-79104 Freiburg, Germany
| | - G. A. Koning
- Laboratory of Experimental Surgical Oncology, Department of Surgical Oncology, Erasmus MC, Erasmus University, PO Box 1738, 3000 DR Rotterdam, The Netherlands
| | - D. J. A. Crommelin
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands
| |
Collapse
|
206
|
Huang X, Xu J, Qiu C, Ren L, Liu L, Wan Y, Zhang N, Peng H, Shao Y. Mucosal priming with PEI/DNA complex and systemic boosting with recombinant TianTan vaccinia stimulate vigorous mucosal and systemic immune responses. Vaccine 2007; 25:2620-9. [PMID: 17280743 DOI: 10.1016/j.vaccine.2006.12.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 11/30/2006] [Accepted: 12/12/2006] [Indexed: 11/29/2022]
Abstract
An effective vaccine strategy for HIV-1 will probably requires the induction and maintenance of both humoral and cellular immunity. We tested a new prime-boost approach of intranasal priming with 10 microg DNA plasmid in the PEI/DNA complexes and boosting with 10(7)PFU of replicative recombinant TianTan vaccinia virus (rTTV) expressing HIV-1 Gag in BALB/c mice. Intranasal priming with PEI/DNA complexes elicited strikingly stronger HIV-specific T-cell (p=0.0358) and IgA immune responses at mucosal sites of lung (p=0.0445) and vaginal tract (p=0.0469) than intranasal priming with naked DNA, though both are followed by the same rTTV boosting. Furthermore, an intramuscular boosting with rTTV could profoundly enhance both T-cell and antibody immune responses raised by intranasal priming. These results demonstrate that the combination of intranasal priming with PEI/DNA complexes and systemic boosting with rTTV is a preferable regimen for induction of both T-cell and humoral immune responses.
Collapse
Affiliation(s)
- Xianggang Huang
- State Key Laboratory for Infectious Diseases Prevention and Control, National Center for AIDS/STD Control and Prevention (NCAIDS), China CDC, Beijing, China
| | | | | | | | | | | | | | | | | |
Collapse
|
207
|
Pham PL, Kamen A, Durocher Y. Large-scale transfection of mammalian cells for the fast production of recombinant protein. Mol Biotechnol 2007; 34:225-37. [PMID: 17172668 DOI: 10.1385/mb:34:2:225] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/11/2022]
Abstract
Recombinant proteins (r-proteins) are increasingly important in fundamental research and for clinical applications. As many of these r-proteins are of human or animal origin, cultivated mammalian cells are the host of choice to ensure their functional folding and proper posttranslational modifications. Large-scale transfection of human embryonic kidney 293 or Chinese hamster ovary cells is now an established technology that can be used in the production of hundreds of milligram to gram quantities of a r-protein in less than 1 mo from cloning of its cDNA. This chapter aims to provide an overview of large-scale transfection technology with a particular emphasis on calcium phosphate and polyethylenimine-mediated gene transfer.
Collapse
Affiliation(s)
- Phuong Lan Pham
- Laboratoire de Biotechnologie Vétérinaire et Alimentaire, Faculté de Médecine Vétérinaire, Université de Montréal, CP5000, Sainte-Hyacinthe (Québec) J2S 7C6, Canada
| | | | | |
Collapse
|
208
|
Wang H, Chen Y, Li XY, Liu Y. Synthesis of Oligo(ethylenediamino)-β-Cyclodextrin Modified Gold Nanoparticle as a DNA Concentrator. Mol Pharm 2007; 4:189-98. [PMID: 17256872 DOI: 10.1021/mp060045s] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel oligo(ethylenediamino)-beta-cyclodextrin-modified gold nanoparticle (OEA-CD-NP) was synthesized as a vector for DNA binding and comprehensively investigated by means of absorption and circular dichroism spectroscopies as well as transmission electron microscopy, and its plasmid transfection efficiency as a carrier into cultivated cells in vitro was also evaluated. Possessing many hydrophobic cavities at the outer space, OEA-CD-NP may have a capability of carrying biological and/or medicinal substrates into cells, which will make it potentially applicable in many fields of material science and biological technology. In contrast with OEA-CD-NP, the oligo(ethylenediamino)-lipoic amido-modified gold nanoparticle (OEA-L-NP) without CD was synthesized to investigate the interaction with DNA. The results showed that OEA-L-NPs could only weakly bind DNA.
Collapse
Affiliation(s)
- Hao Wang
- Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, PR China
| | | | | | | |
Collapse
|
209
|
Abstract
Delivery of genes to the airway epithelium for therapeutic purposes seemed easy at first, because the epithelial cells interface with the environment and are therefore accessible. However, problems encountered were more substantial than were originally expected. Nonviral systems may be preferred for long-term gene expression, for they can be dosed repeatedly. Two nonviral gene transfer systems have been in clinical trials, lipid-mediated gene transfer and DNA nanoparticles. Both have sufficient efficiency to be candidates for correction of the cystic fibrosis defect, and both can be dosed repeatedly. However, lipid-mediated gene transfer in the first generation provokes significant inflammatory toxicity, which may be engineered out by adjustments of the lipids, the plasmid CpG content, or both. Both lipid-mediated gene transfer and DNA nanoparticles in the first generation have short duration of expression, but reengineering of the plasmid DNA to contain mostly eukaryotic sequences may address this problem. Considerable advances in the understanding of the cellular uptake and expression of these agents and in their practical utility have occurred in the last few years; these advances are reviewed here.
Collapse
Affiliation(s)
- Pamela B Davis
- Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
| | | |
Collapse
|
210
|
Schmaljohann D. Thermo- and pH-responsive polymers in drug delivery. Adv Drug Deliv Rev 2006; 58:1655-1670. [PMID: 17125884 DOI: 10.1081/e-ebppc-120050042] [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: 09/21/2006] [Accepted: 09/29/2006] [Indexed: 05/27/2023]
Abstract
Stimuli-responsive polymers show a sharp change in properties upon a small or modest change in environmental condition, e.g. temperature, light, salt concentration or pH. This behaviour can be utilised for the preparation of so-called 'smart' drug delivery systems, which mimic biological response behaviour to a certain extent. The possible environmental conditions to use for this purpose are limited due to the biomedical setting of drug delivery as application. Different organs, tissues and cellular compartments may have large differences in pH, which makes the pH a suitable stimulus. Therefore the majority of examples, discussed in this paper, deal with pH-responsive drug delivery system. Thermo-responsive polymer is also covered to a large extent, as well as double-responsive system. The physico-chemical behaviour underlying the phase transition will be discussed in brief. Then selected examples of applications are described.
Collapse
Affiliation(s)
- Dirk Schmaljohann
- Centre for Polymer Therapeutics, Welsh School of Pharmacy, Cardiff University and Cardiff Institute of Tissue Engineering and Repair (CITER), Redwood Building, King Edward VII Avenue, Cardiff, CF10 3XF, Wales, UK.
| |
Collapse
|
211
|
|
212
|
von Gersdorff K, Sanders NN, Vandenbroucke R, De Smedt SC, Wagner E, Ogris M. The Internalization Route Resulting in Successful Gene Expression Depends on both Cell Line and Polyethylenimine Polyplex Type. Mol Ther 2006; 14:745-53. [PMID: 16979385 DOI: 10.1016/j.ymthe.2006.07.006] [Citation(s) in RCA: 242] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 07/07/2006] [Accepted: 07/11/2006] [Indexed: 11/23/2022] Open
Abstract
Understanding cellular uptake and intracellular processing of nonviral gene delivery systems is a key aspect in developing more efficient vectors. In this study, the impact of clathrin- and caveolae/lipid-raft-dependent endocytosis on cell entry and overall transfection efficiency of polyethylenimine (PEI) polyplexes was evaluated. Most remarkably, the internalization pathway mediating successful transfection depended on both cell type and polyplex type applied. Colocalization studies with transferrin and cholera toxin B revealed that at least two specific endocytosis pathways--the clathrin-dependent and the lipid-raft-dependent--mediated cellular uptake of PEI polyplexes. With the help of specific uptake inhibitors (chlorpromazine and filipin III), cell-line-dependent variations regarding the route of successful transfection were observed (HUH-7, COS-7, HeLa). In COS-7 cells, the clathrin-dependent pathway was the main contributor to the transfection process. In HUH-7 cells, gene transfer by linear PEI polyplexes succeeded mainly via the clathrin-dependent route, whereas transfection by branched PEI polyplexes was mediated by both pathways. In HeLa cells, both pathways were able to mediate successful gene delivery. However, the lipid-raft-dependent pathway was more relevant. The study also revealed that the concentration window between specific inhibitory function and nonspecific toxicity of the uptake inhibitors was very narrow.
Collapse
Affiliation(s)
- Katharina von Gersdorff
- Pharmaceutical Biology-Biotechnology, Department of Pharmacy, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, D-81377 Munich, Germany
| | | | | | | | | | | |
Collapse
|
213
|
Bertschinger M, Backliwal G, Schertenleib A, Jordan M, Hacker DL, Wurm FM. Disassembly of polyethylenimine-DNA particles in vitro: Implications for polyethylenimine-mediated DNA delivery. J Control Release 2006; 116:96-104. [PMID: 17079047 DOI: 10.1016/j.jconrel.2006.09.006] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 09/04/2006] [Accepted: 09/14/2006] [Indexed: 11/26/2022]
Abstract
Here a simple in vitro assay was used to investigate the disassembly of nanoparticles of polyethylenimine (PEI) and DNA. Particles were formed with various PEIs, allowed to mature for 10 min, and then exposed to different competitors (RNA, DNA, BSA or heparin) or to different conditions of pH or osmolarity. DNA release was determined by gel electrophoresis or spectroscopy. The presence of heparin or high salt yielded complete particle disassembly for all PEIs tested. The addition of RNA to particles formed with linear PEIs or branched 2 kDa PEI resulted in rapid DNA release, but RNA induced only partial disassembly of particles formed with large branched PEIs. In the presence of competitor DNA, slow disassembly was observed with particles made with linear PEIs or branched 2 kDa PEI but not for particles made with larger branched PEIs. The presence of BSA resulted in partial disassembly of PEI-DNA particles, but acidic pH did not affect particle stability. If particles were allowed to mature longer than 10 min in NaCl, subsequent heparin-mediated DNA release decreased as the incubation time and the PEI:DNA ratio increased. However, particles that matured in culture medium were disassembled by heparin independently of maturation time or PEI:DNA ratio. It was concluded that branched PEIs have a higher affinity for DNA than linear PEIs, that the intracellular disassembly of PEI-DNA particles may involve interactions between PEI and cellular RNA, and that extended maturation of PEI-DNA particles in NaCl prior to transfection may limit the intracellular release of plasmid DNA.
Collapse
Affiliation(s)
- Martin Bertschinger
- Laboratory of Cellular Biotechnology, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH 1015 Lausanne, Switzerland
| | | | | | | | | | | |
Collapse
|
214
|
Lechardeur D, Lukacs GL. Nucleocytoplasmic transport of plasmid DNA: a perilous journey from the cytoplasm to the nucleus. Hum Gene Ther 2006; 17:882-9. [PMID: 16972756 DOI: 10.1089/hum.2006.17.882] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Nonviral vectors represent a promising approach for the safe delivery of therapeutic DNA in genetic and acquired human diseases. Before synthetic vector systems can be used for clinical applications, their limited efficacy must be addressed. At the cellular level, successful gene transfer is dependent on several additional factors including DNA uptake, release from the DNA-vector complex, and nucleocytoplasmic transport. This paper reviews the major metabolic and physical impediments that plasmid DNA vectorized by synthetic vectors encounters between the cytosol and the nucleus. Plasmid DNA that escapes the endolysosomal compartment encounters the diffusional and metabolic barriers of the cytoplasm, reducing the number of intact plasmids that reach the nuclear envelope. Nuclear translocation of DNA requires either the disassembly of the nuclear envelope during cell division or active nuclear transport via the nuclear pore complex. In the nucleus, plasmid DNA is relatively stable, but its transcription and its fate during cell division are still debated. A better understanding of the cellular and molecular basis of nonviral gene transfer during nucleocytoplasmic trafficking may provide strategies to overcome those obstacles that limit the efficiency of nonviral gene delivery. We review some of the current methods of gene transfer mediated by synthetic vectors, highlighting systems that exploit our actual knowledge of the nucleocytoplasmic transport of plasmid DNA.
Collapse
Affiliation(s)
- Delphine Lechardeur
- Hospital for Sick Children, Program in Cell and Lung Biology, Department of Biochemistry and Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, M5G 1X8 Canada.
| | | |
Collapse
|
215
|
Breunig M, Lungwitz U, Liebl R, Klar J, Obermayer B, Blunk T, Goepferich A. Mechanistic insights into linear polyethylenimine-mediated gene transfer. Biochim Biophys Acta Gen Subj 2006; 1770:196-205. [PMID: 17123738 DOI: 10.1016/j.bbagen.2006.10.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Revised: 09/08/2006] [Accepted: 10/02/2006] [Indexed: 11/23/2022]
Abstract
We recently debuted a variety of linear polyethylenimines (LPEIs) with low molecular weight as carriers for gene delivery. The highest transfection efficiency (approximately 44%) was obtained with LPEI 6.6 kDa, while the cytotoxicity remained low (approximately 90% of CHO-K1 cells survived the transfection procedure). Here, we investigated various steps during the transfection process using LPEI 8.1, 5.0 and 1.8 kDa, in order to gain a more complete insight into LPEI-mediated gene transfer and to explore conceptual aspects for further optimization. The cellular uptake characterized by flow cytometry was similar for LPEI 8.1 and 5.0 kDa, while it was significantly lower for LPEI 1.8 kDa. The transfection efficacy in contrast was at NP 24 20.07% for LPEI 8.1 kDa and 39.71% for LPEI 5.0 kDa. This suggests that the endocytosis seems not to be a decisive parameter that determines the efficacy of a polymer in the transfection process. Real-time PCR investigations revealed that LPEI 1.8 kDa likewise or even better protected plasmid from degradation compared to LPEI 5.0 or 8.1 kDa. Furthermore, we found that 1/6 to 1/3 intact plasmid DNA reached the intracellular compartments after complexation with LPEI 1.8 kDa. Therefore, the amount of plasmid DNA available in the cytoplasm seems not to be a limiting factor in the transfection process. That LPEI 8.1-polyplexes built at NP 12 in glucose and transfected in serum-free culture conditions were superior to those built in sodium chloride or transfected in serum-containing conditions points at the structure as a decisive parameter deserving more attention in future studies.
Collapse
Affiliation(s)
- Miriam Breunig
- Department of Pharmaceutical Technology, University of Regensburg, Universitaetsstrasse 31, 93040 Regensburg, Germany
| | | | | | | | | | | | | |
Collapse
|
216
|
Grosse S, Thévenot G, Monsigny M, Fajac I. Which mechanism for nuclear import of plasmid DNA complexed with polyethylenimine derivatives? J Gene Med 2006; 8:845-51. [PMID: 16685744 DOI: 10.1002/jgm.915] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND To investigate the nuclear import mechanism of plasmid/polyethylenimine (PEI) derivative complexes and the putative nuclear targeting of therapeutic genes by the use of oligosaccharides, we have studied the nuclear import of plasmid DNA complexed either with PEI or with lactosylated PEI (Lac-PEI) in cystic fibrosis human airway epithelial cells ( summation operatorCFTE29o- cells). METHODS AND RESULTS Cells were synchronized by a double-thymidine block protocol and gene transfer efficiency was evaluated: Lac-PEI- and PEI-mediated gene transfer was greatly increased when cells have undergone mitosis during the course of transfection. However, both types of complexes were able to transfect some growth-arrested cells. When the nuclear import of plasmid/Lac-PEI or plasmid/unsubstituted PEI complexes was studied in digitonin-permeabilized cells, the nuclear uptake of both types of complexes did not follow the classic pathway of nuclear localization sequence (NLS)-containing proteins and lactose residues did not act as a nuclear localization signal. CONCLUSIONS Our results show that for complexes made with PEI derivatives, the major route for plasmid DNA nuclear entry is a passive nuclear importation during mitosis when the nuclear membrane temporarily breaks down. However, albeit to a lesser extent as that observed in dividing cells, a plasmid DNA importation also occurs in nondividing cells by a yet unknown mechanism.
Collapse
Affiliation(s)
- Stéphanie Grosse
- Université Paris-Descartes, Faculté de Médecine, AP-HP, Hôpital Cochin, EA 2511, Paris, France
| | | | | | | |
Collapse
|
217
|
Zuhorn IS, Engberts JBFN, Hoekstra D. Gene delivery by cationic lipid vectors: overcoming cellular barriers. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2006; 36:349-62. [PMID: 17019592 DOI: 10.1007/s00249-006-0092-4] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Revised: 08/16/2006] [Accepted: 08/25/2006] [Indexed: 12/11/2022]
Abstract
Non-viral vectors such as cationic lipids are capable of delivering nucleic acids, including genes, siRNA or antisense RNA into cells, thus potentially resulting in their functional expression. These vectors are considered as an attractive alternative for virus-based delivery systems, which may suffer from immunological and mutational hazards. However, the efficiency of cationic-mediated gene delivery, although often sufficient for cell biological purposes, runs seriously short from a therapeutics point of view, as realizing this objective requires a higher level of transfection than attained thus far. To develop strategies for improvement, there is not so much a need for novel delivery systems. Rather, better insight is needed into the mechanism of delivery, including lipoplex-cell surface interaction, route of internalization and concomitant escape of DNA/RNA into the cytosol, and transport into the nucleus. Current work indicates that a major obstacle involves the relative inefficient destabilization of membrane-bounded compartments in which lipoplexes reside after their internalization by the cell. Such an activity requires the capacity of lipoplexes of undergoing polymorphic transitions such as a membrane destabilizing hexagonal phase, while cellular components may aid in this process. A consequence of the latter notion is that for development of a novel generation of delivery devices, entry pathways have to be triggered by specific targeting to select delivery into intracellular compartments which are most susceptible to lipoplex-induced destabilization, thereby allowing the most efficient release of DNA, a minimal requirement for optimizing non-viral vector-mediated transfection.
Collapse
Affiliation(s)
- Inge S Zuhorn
- Department of Cell Biology, Section Membrane Cell Biology, University Medical Center Groningen, Groningen, The Netherlands
| | | | | |
Collapse
|
218
|
Lechardeur D, Lukacs GL. Nucleocytoplasmic Transport of Plasmid DNA: A Perilous Journey from the Cytoplasm to the Nucleus. Hum Gene Ther 2006. [DOI: 10.1089/hum.2006.17.ft-238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
219
|
Mishra S, Heidel JD, Webster P, Davis ME. Imidazole groups on a linear, cyclodextrin-containing polycation produce enhanced gene delivery via multiple processes. J Control Release 2006; 116:179-91. [PMID: 16891028 DOI: 10.1016/j.jconrel.2006.06.018] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2006] [Revised: 06/20/2006] [Accepted: 06/21/2006] [Indexed: 11/23/2022]
Abstract
The linear, cyclodextrin-containing polycation (CDP) is one of many non-viral gene delivery vectors that show improved transfection efficiency when modified to have pH-buffering capacity. The buffering activity is presumed to confer enhanced ability to escape the endocytic pathway. Here, the differences in delivery behavior between CDP and its pH-buffering, imidazole-containing variant (CDPim) are investigated in order to elucidate the mechanism(s) by which these related materials exhibit differences in gene delivery. In cell-free assays that include dye exclusion and heparan sulfate displacement, CDP appears to have weaker binding strength with nucleic acids than CDPim. Numerous analyses involving transfected cells, however, indicate that CDPim more readily releases nucleic acids in the intracellular setting. Together, these data suggest that differences in transfection efficiency between CDP and CDPim result from factors beyond buffering activity and endosomal escape.
Collapse
Affiliation(s)
- Swaroop Mishra
- Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | | | | | | |
Collapse
|
220
|
Remaut K, Lucas B, Braeckmans K, Sanders NN, Demeester J, De Smedt SC. Delivery of phosphodiester oligonucleotides: can DOTAP/DOPE liposomes do the trick? Biochemistry 2006; 45:1755-64. [PMID: 16460022 DOI: 10.1021/bi0519755] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Delivering phosphodiester ONs (PO-ONs) remains an attractive but challenging goal in antisense therapy. Both in the literature and in our experiments, most cationic liposomes fail in generating an antisense effect with PO-ONs, while they succeed with chemically modified ONs such as phosphothioate ONs (PS-ONs). This work aims to explain the biological activity of PO- and PS-ONs delivered by DOTAP/DOPE liposomes based on a detailed understanding of their cell biological behavior by means of fluorescence correlation spectroscopy and confocal laser scanning microscopy. We conclude that DOTAP/DOPE liposomes are not suited to deliver PO-ONs due to the release of naked PO-ONs in the cytosol at the time of the endosomal escape of the liposomes and the subsequent rapid degradation of the naked PO-ONs. Carriers that would not release the PO-ONs upon endosomal escape but would continue to carry the PO-ONs until they arrive at the target mRNA could therefore be better suited to delivering PO-ONs. In the case of PS-ONs, the ONs are not degraded upon release at the time of the endosomal escape of the liposomes, creating a pool of intact, biologically active PS-ONs and thus making DOTAP/DOPE liposomes mainly suitable for delivering nuclease resistant ONs. However, the cells seemed to display an export pathway for removing intact PS-ONs from the cells, limiting the presence of naked PS-ONs in the nucleus to approximately 8 h following the delivery.
Collapse
Affiliation(s)
- K Remaut
- Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium
| | | | | | | | | | | |
Collapse
|
221
|
Talsma SS, Babensee JE, Murthy N, Williams IR. Development and in vitro validation of a targeted delivery vehicle for DNA vaccines. J Control Release 2006; 112:271-9. [PMID: 16549219 DOI: 10.1016/j.jconrel.2006.02.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Revised: 02/09/2006] [Accepted: 02/15/2006] [Indexed: 10/24/2022]
Abstract
Usage of DNA vaccination has been limited by inefficient cellular expression of plasmid constructs used in DNA vaccines. We describe a novel system for enhancing delivery of DNA vaccine plasmids into cells and their nuclei. This delivery system uses recombinant reovirus type 3 sigma1 attachment protein genetically modified with a nuclear localization sequence (sigma1-NLS) as a targeting ligand. Purified sigma1-NLS was covalently conjugated to the polycation polyethyleneimine (PEI) using a carboxyl-reactive cross-linking agent and complexed with plasmid DNA. The benefit of the NLS in enhancement of protein delivery into the nucleus was demonstrated by liposome-mediated loading of cells with sigma1 or sigma1-NLS. In L929 fibroblasts loaded with sigma1-NLS, 69% of the internalized protein was recovered in the nuclear fraction after 6 h compared to just 10% when using unmodified sigma1. Transfection of L929 cells with sigma1-NLS-conjugated PEI complexed with a luciferase expression plasmid resulted in a mean 16-fold increase in luciferase activity over complexes made with unmodified PEI, compared to a mean 3-fold boost obtained using sigma1-conjugated PEI. These results suggest that sigma1-NLS is a useful bifunctional targeting ligand suitable for enhancing DNA delivery and subsequent gene expression for both DNA vaccine applications and nonviral gene therapy.
Collapse
Affiliation(s)
- Silke S Talsma
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, Suite 2127, Atlanta, GA 30332-0535, USA
| | | | | | | |
Collapse
|
222
|
Abstract
Since the evolution of the concept of gene therapy, delivering therapeutic genes to the diseased cells has been a major challenge. Although viral vectors have been shown to be efficient in delivering genes, the issue of their safety is still to be solved. Meanwhile, the field of developing nonviral expression vectors has seen considerable progress. As compared with viruses, these are relatively safe but are confronted with the problem of poor transfection efficiency. With the growing understanding of the biology of gene transfection, and the continued efforts at enhancing the efficiency of nonviral expression vectors, it could soon become a preferred option for human gene therapy. In this review, the potential of polymeric nanoparticles as a gene expression vector is discussed. Furthermore, the importance of understanding the pathophysiology of disease conditions in developing gene expression vectors is discussed in Section 6.
Collapse
Affiliation(s)
- Jaspreet K Vasir
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | | |
Collapse
|
223
|
Hama S, Akita H, Ito R, Mizuguchi H, Hayakawa T, Harashima H. Quantitative Comparison of Intracellular Trafficking and Nuclear Transcription between Adenoviral and Lipoplex Systems. Mol Ther 2006; 13:786-94. [PMID: 16364692 DOI: 10.1016/j.ymthe.2005.10.007] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2005] [Revised: 09/30/2005] [Accepted: 10/01/2005] [Indexed: 10/25/2022] Open
Abstract
To develop nonviral gene vectors that are sufficient for clinical application, it is necessary to understand why and to what extent nonviral vectors are inferior to viral vectors, which in general show a more efficient transfection activity. This study describes a systematic and quantitative comparison of the cellular uptake and subsequent intracellular distribution (e.g., endosome/lysosome, cytosol, and nucleus) of exogenous DNA transfected by viral and nonviral vectors in living cells, using a combination of TaqMan PCR and a recently developed confocal image-assisted three-dimensionally integrated quantification method. As a model, adenovirus (Ad) and Lipofectamine Plus (LFN) were used for comparison since they are highly potent and widely used viral and nonviral vectors, respectively. The findings indicate that the efficiency of cellular uptake for LFN is significantly higher than that for Ad. Once taken up by a cell, Ad exhibited comparable endosomal escape and slightly higher nuclear transfer efficiency compared with LFN. In contrast, LFN requires 3 orders of magnitude more intranuclear gene copies to exhibit a transgene expression comparable to that of the Ad, suggesting that the difference in transfection efficiency principally arises from differences in nuclear transcription efficiency and not from a difference in intracellular trafficking between Ad and LFN.
Collapse
Affiliation(s)
- Susumu Hama
- Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido 060-0812, Japan
| | | | | | | | | | | |
Collapse
|
224
|
Breunig M, Lungwitz U, Liebl R, Fontanari C, Klar J, Kurtz A, Blunk T, Goepferich A. Gene delivery with low molecular weight linear polyethylenimines. J Gene Med 2006; 7:1287-98. [PMID: 15906395 DOI: 10.1002/jgm.775] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Linear polyethylenimine (LPEI) with a molecular weight (MW) of 22 kDa has been described as having a superior ability to induce gene transfer compared to its branched form. However, the transfection efficiency of the polymer cannot be enhanced beyond a certain limit due to cytotoxicity. We explored the potential of utilizing LPEIs with MWs ranging from 1.0 to 9.5 kDa to overcome this limitation. METHODS Polyplexes of plasmid DNA encoding for the enhanced green fluorescent protein (EGFP) and various LPEIs were compared concerning their transfection efficiency and cytotoxicity in CHO-K1 and HeLa cells by flow cytometry. The involvement of endolysosomes in LPEI-mediated gene transfer was investigated by applying the proton pump inhibitor bafilomycin A1 and the lysosomotropic agent sucrose. Confocal laser scanning microscopy was applied to assess the size and shape of polyplexes under cell culture conditions, to detect their endolysosomal localization and to observe their translocation to the nucleus. RESULTS The transfection efficiency could be altered by varying the MW and the amount of the polymer available for polyplex formation. The highest transfection efficiency (about 44%), i.e. the fraction of EGFP-positive cells, was obtained with LPEI 5.6 kDa, while the cytotoxicity remained low. The colocalization of polyplexes and endolysosomes was observed, and it appeared that the larger polyplexes escaped from the acidic organelles particularly quickly. For LPEI 5.0 and 9.0 kDa, the number of cells and nuclei that had taken up DNA after 6 hours was similar, as determined by flow cytometry. CONCLUSIONS Our study suggests that LPEIs with low MWs are promising candidates for non-viral gene delivery, because they are more efficient and substantially less toxic than their higher MW counterparts.
Collapse
Affiliation(s)
- Miriam Breunig
- Department of Pharmaceutical Technology, University of Regensburg, Universitaetsstrasse 31, 93040 Regensburg, Germany
| | | | | | | | | | | | | | | |
Collapse
|
225
|
Breunig M, Lungwitz U, Liebl R, Goepferich A. Fluorescence resonance energy transfer: evaluation of the intracellular stability of polyplexes. Eur J Pharm Biopharm 2006; 63:156-65. [PMID: 16527471 DOI: 10.1016/j.ejpb.2006.01.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Revised: 12/21/2005] [Accepted: 01/27/2006] [Indexed: 10/24/2022]
Abstract
The investigation of intracellular mechanisms of non-viral nucleic acid delivery systems has provided great impetus for the improvement of their efficacy. Especially the intracellular release of the nucleic acid from the non-viral carrier system may be a relevant criterion for the high transfection efficiency of certain polymers. Therefore, we evaluated fluorescence resonance energy transfer (FRET) in combination with confocal laser scanning microscopy or flow cytometry as tool to determine the intracellular disintegration of polyplexes built with plasmid DNA and linear polyethylenimine. In microscopy, which allowed for an observation of polyplexes within single cells, sensitized emission measurement and acceptor photobleaching have been tested towards quantitative FRET analysis. In contrast, the whole cell population was analyzed by the flow cytometry-based method. We suggest that FRET is a useful tool to evaluate the intracellular disintegration of polyplexes built with various polymers.
Collapse
Affiliation(s)
- Miriam Breunig
- Department of Pharmaceutical Technology, University of Regensburg, Regensburg, Germany
| | | | | | | |
Collapse
|
226
|
Glodde M, Sirsi SR, Lutz GJ. Physiochemical properties of low and high molecular weight poly(ethylene glycol)-grafted poly(ethylene imine) copolymers and their complexes with oligonucleotides. Biomacromolecules 2006; 7:347-56. [PMID: 16398535 DOI: 10.1021/bm050726t] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inefficient delivery of antisense oligonucleotides (AOs) to target cell nuclei remains as the foremost limitation to their usefulness. Copolymers of cationic poly(ethylene imine) (PEI) and poly(ethylene glycol) (PEG) have been well-studied for delivery of plasmids. However, the properties of PEG-PEI-AO polyplexes have not been comprehensively investigated. Therefore, we synthesized a series of PEG-PEI copolymers and evaluated their physiochemical properties alone and when complexed with AO. The M(w) of PEG was found to be the main determinant of polyplex size, via its influence on particle aggregation. DLS measurements showed that when PEG5000 was grafted to PEI2K and PEI25K, polyplex diameters were extremely small (range 10-90 nm) with minimal aggregation. In contrast, when PEG550 was grafted to PEI2K and PEI25K, polyplexes appeared as much larger aggregates (approximately 250 nm). As expected, the surface charge (zeta potential) was higher for polyplexes containing PEI25K than those containing PEI2K, but decreased with increased levels of PEG grafting. Surprisingly, within the physiological range (pH 7.5-5), the buffering capacity of all copolymers was nearly equivalent to that of unsubstituted PEI2K or PEI25K, and was barely influenced by PEGylation. The stability of polyplexes was evaluated using a heparin polyanion competition assay. Unexpectedly, polyplexes containing PEI2K showed stability equal to or greater than that of PEI25K polyplexes. The level of PEG grafting also had a dramatic effect on polyplex stability. The relationships established between molecular formulations and polyplex size, aggregation, surface charge, and stability should provide a useful guide for future studies aimed at optimizing polymer-mediated AO delivery in cell and animal studies. A summary of the relationships between polyplex structures and recent studies of their transfection capacity is provided.
Collapse
Affiliation(s)
- Martin Glodde
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | | | | |
Collapse
|
227
|
Williams JH, Sirsi SR, Latta DR, Lutz GJ. Induction of dystrophin expression by exon skipping in mdx mice following intramuscular injection of antisense oligonucleotides complexed with PEG-PEI copolymers. Mol Ther 2006; 14:88-96. [PMID: 16488666 DOI: 10.1016/j.ymthe.2005.11.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Revised: 11/19/2005] [Accepted: 11/25/2005] [Indexed: 11/16/2022] Open
Abstract
Antisense oligonucleotides (AOs) with 2-O-methyl modifications can circumvent dystrophin mutations via exon skipping and, it is hoped, can become drugs for treatment of Duchenne muscular dystrophy (DMD). However, AO-based approaches are hindered by a lack of effective carriers to facilitate delivery of AOs to myonuclei. We examined whether copolymers composed of cationic poly(ethylene imine) (PEI) and polyethylene glycol (PEG) can enhance AO transfection in skeletal muscle of mdx mice. Single intramuscular injections of AO complexed with low Mw PEI2000(PEG550) copolymers into TA muscles of mdx mice resulted in widespread distribution of dystrophin-positive fibers at 3 weeks after injection, with no apparent cytotoxicity. Overall, injections of these low Mw polyplexes, which formed 250-nm aggregate particles, resulted in about sixfold more dystrophin-positive fibers than AO alone. Western analysis confirmed the dystrophin expression in these muscles. Surprisingly, injections of AO complexed with high Mw PEI25000(PEG5000) copolymers, which formed smaller nonaggregated particles, produced about threefold fewer dystrophin-positive fibers than injections of the low Mw polyplexes. We conclude that low Mw PEI2000(PEG550) copolymers function as high-capacity, nontoxic AO carriers suitable for in vivo transfection of skeletal muscle and are promising compounds for potential use in molecular therapy of DMD.
Collapse
MESH Headings
- Alternative Splicing/drug effects
- Animals
- Base Sequence
- Blotting, Western
- Dystrophin/genetics
- Dystrophin/metabolism
- Exons/genetics
- Genetic Therapy/methods
- Immunohistochemistry
- Injections, Intramuscular
- Mice
- Mice, Inbred mdx
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscular Dystrophy, Animal/genetics
- Muscular Dystrophy, Animal/metabolism
- Muscular Dystrophy, Animal/therapy
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/metabolism
- Muscular Dystrophy, Duchenne/therapy
- Oligonucleotides, Antisense/administration & dosage
- Oligonucleotides, Antisense/chemistry
- Oligonucleotides, Antisense/genetics
- Polyethylene Glycols/chemistry
- Polyethyleneimine/chemistry
- Transfection/methods
Collapse
Affiliation(s)
- Jason H Williams
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Mailstop 488, NCB 8302, Philadelphia, PA 19102, USA
| | | | | | | |
Collapse
|
228
|
Sirsi SR, Williams JH, Lutz GJ. Poly(ethylene imine)-poly(ethylene glycol) copolymers facilitate efficient delivery of antisense oligonucleotides to nuclei of mature muscle cells of mdx mice. Hum Gene Ther 2006; 16:1307-17. [PMID: 16259564 DOI: 10.1089/hum.2005.16.1307] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Antisense oligonucleotides (AO) can facilitate dystrophin expression via targeted exon skipping in cultured cells of Duchenne muscular dystrophy (DMD) patients and in the mouse model of DMD (mdx mice). However, the lack of effective means to deliver AO to myonuclei remains the foremost limitation to their usefulness in DMD gene therapy. In this study we show that copolymers of cationic poly(ethylene imine) (PEI) and poly(ethylene glycol) (PEG) facilitated efficient cellular uptake and nuclear delivery of AO in mature skeletal muscle fibers isolated from mdx mice. Confocal analysis of dual fluorescently tagged PEG-PEI-AO polyplexes, 24 hr after transfection, showed that the copolymer and AO were colocalized within punctate membrane- associated structures. Importantly, AO was efficiently translocated into myonuclei, whereas the copolymer was mostly excluded. The morphology of all transfected myofibers was perfectly maintained with no indication of damage or cytotoxicity. Quantitative fluorescence analysis showed that transfection with PEG-PEI-AO resulted in a 6-fold higher uptake of AO into myonuclei compared with transfections of AO alone. Interestingly, transfections with rhodamine-labeled PEG-PEI copolymers yielded an approximately 2- fold higher uptake of AO into myonuclei compared with transfections of unlabeled copolymers. Attempts to further increase AO delivery by addition of insulin-transferrin-selenium (ITS) to the medium showed no further improvement in AO delivery. Dose-response analysis indicated saturation of endocytotic uptake of the polyplex. Overall, we conclude that PEG-PEI copolymers represent high-capacity, nontoxic carriers for efficient delivery of AO to nuclei of mature myofibers.
Collapse
Affiliation(s)
- Shashank R Sirsi
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | | | | |
Collapse
|
229
|
Huth S, Hoffmann F, von Gersdorff K, Laner A, Reinhardt D, Rosenecker J, Rudolph C. Interaction of polyamine gene vectors with RNA leads to the dissociation of plasmid DNA-carrier complexes. J Gene Med 2006; 8:1416-24. [PMID: 17029296 DOI: 10.1002/jgm.975] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Plasmid DNA (pDNA) dissociation from polyamine gene vectors after cellular uptake has not been well characterized. A more detailed understanding of this process could lead to more efficient gene transfer agents. Since RNA is present in the cytoplasm at high concentrations and due to its structural similarity to DNA, we were interested in its conceivable interaction with polyamine gene vectors. METHODS In a first set of experiments gene vectors were incubated in cell lysate and pDNA release was investigated by Southern blot analysis with or without RNase A pretreatment and by confocal laser scanning microscopy. Further, interaction of polyamine gene vectors with RNA was investigated by fluorescence quenching assay. These methods were complemented by a functionality assay using isolated nuclei. RESULTS The incubation of gene vectors with cell lysate resulted in the dissociation of pDNA from the complexes. This effect was abolished when the cell lysate was pretreated with RNase A. The addition of RNA in the absence of cell lysate led also to a dissociation of pDNA. This process commenced instantaneously after the addition of RNA as analyzed by fluorescence quenching. When gene vectors were incubated in cell lysate containing isolated nuclei, the dissociation of pDNA from the polyamine gene vectors occurred preferentially extranuclearally as confirmed by confocal laser scanning microscopy. These results were further corroborated in a functional assay. CONCLUSIONS These data suggest that RNA induces pDNA dissociation from the polyamine gene vectors. Furthermore, this process apparently occurs in the cytoplasm before the gene vectors enter the nucleus.
Collapse
Affiliation(s)
- Stephanie Huth
- Department of Pediatrics, Ludwig-Maximilians-University, 80337 Munich, Germany
| | | | | | | | | | | | | |
Collapse
|
230
|
Oupicky D, Bisht HS, Manickam DS, Zhou QH. Stimulus-controlled delivery of drugs and genes. Expert Opin Drug Deliv 2005; 2:653-65. [PMID: 16296792 DOI: 10.1517/17425247.2.4.653] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Macromolecular and colloidal systems used for the systemic delivery of drugs and genes promise to improve the way we treat and prevent numerous diseases. New generations of drug and gene delivery systems (DGDS) are being designed to enhance further efficiency by using a range of endogenous and external stimuli. This review focuses on three qualitatively distinct ways a stimulus can improve the efficiency of DGDS; namely, by selectively triggering release of the therapeutic agent from the DGDS, by modulating physical properties of DGDS and by favourably altering physiological properties of tissues to enhance DGDS transport. Recent developments in these areas are discussed to illustrate the potential of stimulus-controlled DGDS in the development of new generations of therapeutics.
Collapse
Affiliation(s)
- David Oupicky
- Wayne State University, Department of Pharmaceutical Sciences, Detroit, MI 48202, USA.
| | | | | | | |
Collapse
|
231
|
Honoré I, Grosse S, Frison N, Favatier F, Monsigny M, Fajac I. Transcription of plasmid DNA: Influence of plasmid DNA/polyethylenimine complex formation. J Control Release 2005; 107:537-46. [PMID: 16087268 DOI: 10.1016/j.jconrel.2005.06.018] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Revised: 06/09/2005] [Accepted: 06/28/2005] [Indexed: 11/18/2022]
Abstract
Polyethylenimine (PEI) is one of the most potent non-viral vectors. We have developed a lactosylated PEI (Lac-PEI) to enhance cell-specific transfection and have shown that Lac-PEI is more efficient than unsubstituted PEI for gene transfer into immortalized cystic fibrosis airway epithelial SigmaCFTE29o-cells. As both intact PEI/plasmid and Lac-PEI/plasmid complexes are found in the cell nucleus, we have investigated the transcription efficiency of the plasmid complexed with PEI or Lac-PEI, according to the polymer nitrogen/DNA phosphate (N/P) ratio (from 0 to 20). The initiation of transgene transcription was analyzed in an acellular nuclease S1 transcription assay. For both PEI and Lac-PEI complexes, transcription efficiency varied with the N/P ratio of the complexes. Transcription inhibition was observed when plasmid DNA was either loosely (N/P<5) or tightly condensed (N/P>15). For an N/P ratio of 5 and up to 15, transcription of the complexed plasmid was as efficient as that of the free plasmid. Similar results were observed when gene expression was studied after nuclear microinjection of the complexes into SigmaCFTE29o-cells. Our study shows that condensation of DNA influences the accessibility of the plasmid to the transcription machinery. Interestingly, the charge ratios that allow the most efficient transcription are those usually known to be the most efficient for gene transfer in vitro and in vivo.
Collapse
Affiliation(s)
- Isabelle Honoré
- Université Paris-Descartes, Faculté de Médecine, AP-HP, Hôpital Cochin, EA 2511, Paris, France
| | | | | | | | | | | |
Collapse
|
232
|
Garzón MR, Berraondo P, Crettaz J, Ochoa L, Vera M, Lasarte JJ, Vales A, Van Rooijen N, Ruiz J, Prieto J, Zulueta J, González-Aseguinolaza G. Induction of gp120-specific protective immune responses by genetic vaccination with linear polyethylenimine-plasmid complex. Vaccine 2005; 23:1384-92. [PMID: 15661387 DOI: 10.1016/j.vaccine.2004.09.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2004] [Revised: 08/13/2004] [Accepted: 09/10/2004] [Indexed: 11/22/2022]
Abstract
The induction of IFN-gamma-secreting CD8+ T cells and neutralizing antibodies to HIV-1 are both key requirements for prevention of viral transmission and clearance of pathogenic HIV. Although DNA vaccination has been shown to induce both humoral and cellular immune responses against HIV antigens, the magnitude of the immune responses has always been disappointing. In this report, we analyze the ability of polyethylenimine (PEI)-DNA complex expressing an HIV-glycoprotein 120 (gp120) antigen (PEI-pgp120) to induce systemic CD8+ T cell and humoral responses to the gp120 antigen. The administration of PEI-plasmid complex resulted in rapid elevation of serum levels of IL-12 and IFN-gamma. Furthermore, a single administration of PEI-pgp120 complex elicits a number of gp120-specific CD8+ T cells 20 times higher than that elicited by three intramuscular injections of naked DNA. Interestingly, we found that systemic vaccination with PEI-pgp120 induced protective immune responses against both systemic and mucosal challenges with a recombinant vaccinia virus expressing a gp120 antigen. The data also demonstrated that the depletion of macrophages with liposome-encapsulated clodronate completely abolished gp120-specific cellular response. Overall, our results showed that a single administration of PEI-pgp120 complexes, eliciting strong immune responses, is an effective vaccination approach to generate protection against systemic and mucosal viral infections.
Collapse
Affiliation(s)
- Manolo Rodrigo Garzón
- Laboratory of Gene Therapy of Viral Hepatitis, Division of Hepatology and Gene Therapy, Clínica Universitaria/School of Medicine, Center for Applied Medical Research, University of Navarra, Pío XII 55, 31080 Pamplona, Spain
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
233
|
Rejman J, Bragonzi A, Conese M. Role of clathrin- and caveolae-mediated endocytosis in gene transfer mediated by lipo- and polyplexes. Mol Ther 2005; 12:468-74. [PMID: 15963763 DOI: 10.1016/j.ymthe.2005.03.038] [Citation(s) in RCA: 642] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2004] [Revised: 03/24/2005] [Accepted: 03/30/2005] [Indexed: 11/20/2022] Open
Abstract
We investigated the effects of inhibitors of clathrin-mediated endocytosis (chlorpromazine and K(+) depletion) and of caveolae-mediated uptake (filipin and genistein) on internalization of FITC-poly-l-lysine-labeled DOTAP/DNA lipoplexes and PEI/DNA polyplexes by A549 pneumocytes and HeLa cells and on the transfection efficiencies of these complexes with the luciferase gene. Uptake of the complexes was assayed by fluorescence-activated cell sorting. Lipoplex internalization was inhibited by chlorpromazine and K(+) depletion but unaffected by filipin and genistein. In contrast, polyplex internalization was inhibited by all four inhibitors. We conclude that lipoplex uptake proceeds only by clathrin-mediated endocytosis, while polyplexes are taken up by two mechanisms, one involving caveolae and the other clathrin-coated pits. Transfection by lipoplexes was entirely abolished by blocking clathrin-mediated endocytosis, whereas inhibition of the caveolae pathway had no effect. By contrast, transfection mediated by polyplexes was completely blocked by genistein and filipin but was unaffected by inhibitors of clathrin-mediated endocytosis. Fluorescence colocalization studies with a lysosomal marker, AlexaFluor-dextran, revealed that polyplexes taken up by clathrin-mediated endocytosis are targeted to the lysosomal compartment for degradation, while the polyplexes internalized via caveolae escape this compartment, permitting efficient transfection.
Collapse
Affiliation(s)
- Joanna Rejman
- Institute for Experimental Treatment of Cystic Fibrosis, HSR Scientific Institute, Via Olgettina 58, 20132 Milan, Italy
| | | | | |
Collapse
|
234
|
Lungwitz U, Breunig M, Blunk T, Göpferich A. Polyethylenimine-based non-viral gene delivery systems. Eur J Pharm Biopharm 2005; 60:247-66. [PMID: 15939236 DOI: 10.1016/j.ejpb.2004.11.011] [Citation(s) in RCA: 727] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2004] [Revised: 11/02/2004] [Accepted: 11/02/2004] [Indexed: 10/25/2022]
Abstract
Gene therapy has become a promising strategy for the treatment of many inheritable or acquired diseases that are currently considered incurable. Non-viral vectors have attracted great interest, as they are simple to prepare, rather stable, easy to modify and relatively safe, compared to viral vectors. Unfortunately, they also suffer from a lower transfection efficiency, requiring additional effort for their optimization. The cationic polymer polyethylenimine (PEI) has been widely used for non-viral transfection in vitro and in vivo and has an advantage over other polycations in that it combines strong DNA compaction capacity with an intrinsic endosomolytic activity. Here, we give some insight into strategies developed for PEI-based non-viral vectors to overcome intracellular obstacles, including the improvement of methods for polyplex preparation and the incorporation of endosomolytic agents or nuclear localization signals. In recent years, PEI-based non-viral vectors have been locally or systemically delivered, mostly to target gene delivery to tumor tissue, the lung or liver. This requires strategies to efficiently shield transfection polyplexes against non-specific interaction with blood components, extracellular matrix and untargeted cells and the attachment of targeting moieties, which allow for the directed gene delivery to the desired cell or tissue. In this context, materials, facilitating the design of novel PEI-based non-viral vectors are described.
Collapse
Affiliation(s)
- U Lungwitz
- Department of Pharmacy and Chemistry, Pharmaceutical Technology Unit, University of Regensburg, Regensburg, Germany
| | | | | | | |
Collapse
|
235
|
Liu X, Yang JW, Miller AD, Nack EA, Lynn DM. Charge-Shifting Cationic Polymers That Promote Self-Assembly and Self-Disassembly with DNA. Macromolecules 2005. [DOI: 10.1021/ma051270a] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xianghui Liu
- Department of Chemical and Biological Engineering, University of WisconsinMadison, 1415 Engineering Drive, Madison, Wisconsin 53706
| | - Jennifer W. Yang
- Department of Chemical and Biological Engineering, University of WisconsinMadison, 1415 Engineering Drive, Madison, Wisconsin 53706
| | - Adam D. Miller
- Department of Chemical and Biological Engineering, University of WisconsinMadison, 1415 Engineering Drive, Madison, Wisconsin 53706
| | - Elizabeth A. Nack
- Department of Chemical and Biological Engineering, University of WisconsinMadison, 1415 Engineering Drive, Madison, Wisconsin 53706
| | - David M. Lynn
- Department of Chemical and Biological Engineering, University of WisconsinMadison, 1415 Engineering Drive, Madison, Wisconsin 53706
| |
Collapse
|
236
|
Akinc A, Thomas M, Klibanov AM, Langer R. Exploring polyethylenimine-mediated DNA transfection and the proton sponge hypothesis. J Gene Med 2005; 7:657-63. [PMID: 15543529 DOI: 10.1002/jgm.696] [Citation(s) in RCA: 999] [Impact Index Per Article: 52.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND The relatively high transfection efficiency of polyethylenimine (PEI) vectors has been hypothesized to be due to their ability to avoid trafficking to degradative lysosomes. According to the proton sponge hypothesis, the buffering capacity of PEI leads to osmotic swelling and rupture of endosomes, resulting in the release of the vector into the cytoplasm. METHODS The mechanism of PEI-mediated DNA transfer was investigated using quantitative methods to study individual steps in the overall transfection process. In addition to transfection efficiency, the cellular uptake, local pH environment, and stability of vectors were analyzed. N-Quaternized (and therefore non-proton sponge) versions of PEI and specific cell function inhibitors were used to further probe the proton sponge hypothesis. RESULTS Both N-quaternization and the use of bafilomycin A1 (a vacuolar proton pump inhibitor) reduced the transfection efficiency of PEI by approximately two orders of magnitude. Chloroquine, which buffers lysosomes, enhanced the transfection efficiency of N-quaternized PEIs and polylysine by 2-3-fold. In contrast, chloroquine did not improve the transfection efficiency of PEI. The measured average pH environment of PEI vectors was 6.1, indicating that they successfully avoid trafficking to acidic lysosomes. Significantly lower average pH environments were observed for permethyl-PEI (pH 5.4), perethyl-PEI (pH 5.1), and polylysine (pH 4.6) vectors. Cellular uptake levels of permethyl-PEI and perethyl-PEI vectors were found to be 20 and 90% higher, respectively, than that of parent PEI vectors, indicating that the reduction in transfection activity of the N-quaternized PEIs is due to a barrier downstream of cellular uptake. A polycation/DNA-binding affinity assessment showed that the more charge dense N-quaternized PEIs bind DNA less tightly than PEI, demonstrating that poor vector unpackaging was not responsible for the reduced transfection activity of the N-quaternized PEIs. CONCLUSIONS The results obtained are consistent with the proton sponge hypothesis and strongly suggest that the transfection activity of PEI vectors is due to their unique ability to avoid acidic lysosomes.
Collapse
Affiliation(s)
- Akin Akinc
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | | | | |
Collapse
|
237
|
Elouahabi A, Ruysschaert JM. Formation and intracellular trafficking of lipoplexes and polyplexes. Mol Ther 2005; 11:336-47. [PMID: 15727930 DOI: 10.1016/j.ymthe.2004.12.006] [Citation(s) in RCA: 320] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2004] [Accepted: 12/11/2004] [Indexed: 10/26/2022] Open
Abstract
Cationic lipid/DNA lipoplexes and cationic polymer/DNA polyplexes represent an attractive alternative to viral vectors for cell transfection in vitro and in vivo but still suffer from a relatively low efficiency. Optimization of their transfection efficiency may be attempted by using a trial and error approach consisting of synthesizing and testing a large number of derivatives. On the other hand, rational design of highly efficient cationic lipids and polymers requires a deeper understanding of the interactions between the vector and the DNA as well as the cellular pathways and mechanisms involved in DNA entry into the cell and ultimately the nucleus. In the present review, the pathways and mechanisms involved in lipoplex- and polyplex-mediated transfection are comparatively addressed and unresolved questions are highlighted.
Collapse
Affiliation(s)
- Abdelatif Elouahabi
- Center for Structural Biology and Bioinformatics, Structure and Function of Biological Membranes, Université Libre de Bruxelles, Campus Plaine CP 206/2, B-1050 Brussels, Belgium
| | | |
Collapse
|
238
|
Kiang T, Bright C, Cheung CY, Stayton PS, Hoffman AS, Leong KW. Formulation of chitosan-DNA nanoparticles with poly(propyl acrylic acid) enhances gene expression. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2005; 15:1405-21. [PMID: 15648571 DOI: 10.1163/1568562042368112] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Poly(propyl acrylic acid) (PPAA) is a polymer specifically designed to disrupt lipid bilayer membranes within a sharply defined pH range. The pH sensitivity can be used to enhance the release of endocytosed drugs into the cytoplasmic compartment of the cell. By incorporating this polymer in a polymeric gene carrier, chitosan, the release of plasmid DNA from the endosomal compartment was enhanced. In vitro transfection studies confirmed that the incorporation of PPAA into the chitosan-DNA nanoparticles enhanced gene expression in both HEK293 and HeLa cells compared to chitosan nanoparticles alone. The dose and time at which PPAA was incorporated during the complex formation affected the release of DNA and transfection efficiency. The optimal dose of PPAA incorporated into the chitosan nanoparticles was determined to be 10 microg, corresponding to a PPAA/DNA weight ratio of 1:1. At this dose, the ternary complexes are approx. 400 nm in size with a net negative surface charge of -17.4 mV. Intracellular trafficking studies confirmed the association of PPAA, DNA and chitosan at 24 h post-transfection and the subsequent release of DNA and PPAA from the chitosan at 48 h. The diffuse appearance of the majority of the DNA and the PPAA at later time points suggests that the PPAA triggered membrane disruption resulting in the release of DNA from the endosomal compartment. Finally, the lack of colocalization between PPAA and Lysotracker indicated that the PPAA-loaded nanoparticles were not trafficked through a lysosomal pathway. This study suggests the promising strategy of including PPAA in the formulation of polymer-DNA complexes for non-viral gene delivery.
Collapse
Affiliation(s)
- Tina Kiang
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | | | | | | | | | | |
Collapse
|
239
|
Kulkarni RP, Mishra S, Fraser SE, Davis ME. Single Cell Kinetics of Intracellular, Nonviral, Nucleic Acid Delivery Vehicle Acidification and Trafficking. Bioconjug Chem 2005; 16:986-94. [PMID: 16029041 DOI: 10.1021/bc050081u] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mechanistic understanding of the intracellular trafficking of nonviral nucleic acid delivery vehicles remains elusive. A live, single cell-based assay is described here that is used to investigate and quantitate the spatiotemporal, intracellular pH microenvironment of polymeric-based nucleic acid delivery vehicles. Polycations such as polyethylenimine (PEI), poly-l-lysine (PLL), beta-cyclodextrin-containing polymers lacking or possessing imidazole termini (CDP or CDP-imid), and cyclodextrin-grafted PEI (CD-PEI) are used to deliver an oligonucleotide containing a single fluorophore with two emission lines that can be employed to measure the pH. Delivery vehicles were also sterically stabilized by addition of poly(ethylene glycol) (PEG) and investigated. The intracellular trafficking data obtained via this new methodology show that vectors such as PEI and CDP-imid can buffer the endocytic vesicles while PLL and CDP do not. Additionally, the PEGylated vectors reveal the same buffering capacity as their unstabilized variants. Here, the live cell, spatiotemporal mapping of these behaviors is demonstrated and, when combined with cell uptake and luciferase expression data, shows that there is not a correlation between buffering capacity and gene expression.
Collapse
Affiliation(s)
- Rajan P Kulkarni
- Option in Biochemistry and Molecular Biophysics, California Institute of Technology, Pasadena, California 91125, USA
| | | | | | | |
Collapse
|
240
|
Tseng WC, Fang TY, Su LY, Tang CH. Dependence of Transgene Expression and the Relative Buffering Capacity of Dextran-Grafted Polyethylenimine. Mol Pharm 2005; 2:224-32. [PMID: 15934783 DOI: 10.1021/mp050007t] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Branched polyethylenimine (PEI) is a cationic polymer capable of forming self-assembly complexes with DNA to become a highly efficient agent used in gene delivery. Conjugation through the primary amines of PEI is a most commonly used approach further to enable the targeting delivery or to improve the stability of the DNA-polymer complexes. An understanding of how the conjugation affects the transfection mechanisms can help in the design of efficient polycationic vectors. In order to investigate the effects of conjugation, folate and the dextrans of molecular weight 1500 (dex-1500) and 10 000 (dex-10000) were used to prepare three different types of PEI conjugates: dextran-PEI, folate-PEI, and folate-dextran-PEI, which were subsequently employed to form complexes with DNA. These conjugates were found to cause less cytotoxicity than the unmodified PEI as revealed by the MTT method, and to be able to deliver an approximate amount of ethidium monoazide labeled plasmid into the cells. The efficiencies of green fluorescent protein (GFP) expression mediated by these conjugates, however, were less efficient than those mediated by the unmodified PEI. A titration experiment suggested that conjugation through the primary amines of PEI resulted in the loss of relative buffering capacity, a major factor aiding the release of plasmid from the endosomes, presumably because the conjugated molecules hindered the protonation of the PEI conjugates. When a quantitative relationship between relative buffering capacity and transfection efficiency was examined, a threshold of relative buffering capacity, around 50% of the unmodified PEI, was noted to be required for minimal detection of GFP positive cells. In addition, the cytotoxicity could be also related to the relative buffering capacity in an approximately linear trend. It is thus concluded that the severe loss of relative buffering capacity by conjugation might be attributed to the inefficiency of transgene expression mediated by the dextran-PEI conjugates.
Collapse
Affiliation(s)
- Wen-Chi Tseng
- Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan.
| | | | | | | |
Collapse
|
241
|
Liu Y, Reineke TM. Hydroxyl stereochemistry and amine number within poly(glycoamidoamine)s affect intracellular DNA delivery. J Am Chem Soc 2005; 127:3004-15. [PMID: 15740138 DOI: 10.1021/ja0436446] [Citation(s) in RCA: 202] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nucleic acid drugs have great potential to treat many devastating aliments, but their application has been hindered by the lack of efficacious and nontoxic delivery vehicles. Here, a new library of poly(glycoamidoamine)s (D1-D4, G1-G4, and M1-M4) has been synthesized by polycondensation of esterified d-glucaric acid (D), dimethyl-meso-galactarate (G), and d-mannaro-1,4:6,3-dilactone (M) with diethylenetriamine (1), triethylenetetramine (2), tetraethylenepentamine (3), and pentaethylenehexamine (4). The stereochemistry of the carbohydrate hydroxyl groups and the number of amine units have been systematically changed in an effort to examine how the polymer chemistry affects the plasmid DNA (pDNA) binding affinity, the compaction of pDNA into nanoparticles (polyplexes), the material cytotoxicity, and the efficacy of nucleic acid delivery. The polymers with four secondary amines (D4, G4, and M4) between the carbohydrates were found to have the highest pDNA binding affinity and the galactarate polymers generally yielded the smallest polyplexes. Delivery studies with pDNA containing the firefly luciferase or beta-galactosidase reporter genes in BHK-21, HeLa, and HepG2 cells demonstrated that all of the poly(glycoamidoamine)s deliver pDNA without cytotoxicity. Polymers D4, G4, and M4 displayed the highest delivery efficiency, where G4 was found to be a particularly effective delivery vehicle. Heparin competition assays indicated that this may be a result of the higher pDNA binding affinity displayed by G4 as compared to D4 and M4. Polyplexes formed by polymers with weaker pDNA affinities may dissociate at the cell surface due to interactions with negatively charged glycosaminoglycans, which would cause a decrease in the number of polyplexes that are endocytosed.
Collapse
Affiliation(s)
- Yemin Liu
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221-0172, USA
| | | |
Collapse
|
242
|
Okuda T, Niidome T, Aoyagi H. Cytosolic soluble proteins induce DNA release from DNA--gene carrier complexes. J Control Release 2005; 98:325-32. [PMID: 15262423 DOI: 10.1016/j.jconrel.2004.05.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2004] [Accepted: 05/14/2004] [Indexed: 01/30/2023]
Abstract
In nonviral transfection systems, the gene carrier/DNA complex must undergo several steps for successful transgene expression. DNA release from the complex is one important step. However, the detailed mechanism of intracellular processes involved in DNA release is not well understood. In this study, to clarify the dissociation of the complex in the cytosol, we investigated whether the DNA release was caused by addition of a cytosolic fraction prepared from mouse liver to the complex. When Lipofectamine (a liposome-type gene carrier) was used as a complex forming reagent with DNA, the cytosolic fraction caused no DNA release from the complex. In contrast, when dendritic poly(L-lysine) and jetPEI (polymer-type gene carriers) were used, DNA release was observed when the complex formed at a low cation/anion ratio. This result showed that a DNA releasing factor was present in the cytosolic fraction, suggesting that in the cytosol the DNA was spontaneously released from a gene carrier/DNA complex when the carrier was a polymer-type gene carrier. Furthermore, this DNA releasing ability of the cytosolic fraction was protease sensitive.
Collapse
Affiliation(s)
- Tatsuya Okuda
- Department of Marine Science and Technology, Graduate School of Science and Technology, Nagasaki University, Nagasaki 852-8521, Japan
| | | | | |
Collapse
|
243
|
Walker GF, Fella C, Pelisek J, Fahrmeir J, Boeckle S, Ogris M, Wagner E. Toward Synthetic Viruses: Endosomal pH-Triggered Deshielding of Targeted Polyplexes Greatly Enhances Gene Transfer in vitro and in vivo. Mol Ther 2005; 11:418-25. [PMID: 15727938 DOI: 10.1016/j.ymthe.2004.11.006] [Citation(s) in RCA: 267] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2004] [Accepted: 11/08/2004] [Indexed: 11/22/2022] Open
Abstract
Nonviral vectors should undergo "virus-like" changes compatible with the steps of gene delivery. Poly(ethylene) glycol (PEG) shielding of DNA/polycation polyplexes protects from nonspecific interactions with the extracellular environment. pH-triggered removal of the shield within the endosome may be advantageous. Polycation and PEG were linked via acylhydrazides or pyridylhydrazines. The pyridylhydrazone prepared from polylysine and propionaldehyde-PEG showed the greatest acid-dependent hydrolysis; at pH 5, 37 degrees C for 10 min, 90% hydrolyzed, while at pH 7.4 the half-life was 1.5 h. Particle size and zeta potential measurements of the polyplexes showed complete deshielding within 1 h at pH 5, while at pH 7.4 the shield remained at 4 h, 37 degrees C. For gene transfection a targeting conjugate was also included in the polyplex, transferrin as ligand for K562 and Neuro2A cells and epidermal growth factor for HUH-7 and Renca-EGFR cells. Marker gene expression showed that the reversibly shielded polyplexes exhibited up to 2 log orders of magnitude higher gene expression in vitro and 1 log magnitude higher gene expression in an in vivo mouse model, compared to the stably shielded control polyplexes. Engineering of polyplexes with more dynamic domains is an encouraging new direction in nonviral vector design.
Collapse
Affiliation(s)
- Greg F Walker
- Pharmaceutical Biology-Biotechnology, Department of Pharmacy, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Room 3.023, D-81377 Munich, Germany.
| | | | | | | | | | | | | |
Collapse
|
244
|
Braun CS, Vetro JA, Tomalia DA, Koe GS, Koe JG, Middaugh CR. Structure/Function Relationships of Polyamidoamine/DNA Dendrimers as Gene Delivery Vehicles. J Pharm Sci 2005; 94:423-36. [PMID: 15614818 DOI: 10.1002/jps.20251] [Citation(s) in RCA: 185] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PAMAM dendrimers are members of a class of polyamine polymers that demonstrate significant gene delivery ability. In this study, a selection of PAMAM dendrimers, spanning a range of sizes (generations 2, 4, 7, and 9) and transfection efficiencies, are characterized by various biophysical methods to search for structural properties that correlate with transfection. Measurements of colloidal properties (size and zeta potential) as a function of charge ratio reveal that highly transfecting dendrimer/DNA complexes have size/zeta potential values between 4 and 8. Circular dichroism (CD) and FTIR spectroscopy of complexes confirm the DNA component remains in B form when associated with all dendrimer generations up to a 5:1 charge ratio (+/-). Isothermal titration calorimetry and differential scanning calorimetry detect changes that are related to polymer structure and charge ratio but do not directly correlate with transfection efficiency. Despite DNA structural and stability changes detected by CD, FTIR, DSC, and ITC that are similar to those seen with other cationic delivery vehicles [e.g., cationic lipids, peptoids/lipitoids, peptides, polyethyleneimines (PEIs), etc.], clear correlations with transfection activity are not readily apparent. This may be due, at least in part, to the heterogeneity of the complexes.
Collapse
Affiliation(s)
- Chad S Braun
- Department of Pharmaceutical Chemistry, University of Kansas, 2095 Constant Ave., Lawrence, Kansas 66047, USA
| | | | | | | | | | | |
Collapse
|
245
|
Twaites B, de las Heras Alarcón C, Alexander C. Synthetic polymers as drugs and therapeutics. ACTA ACUST UNITED AC 2005. [DOI: 10.1039/b410799n] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
246
|
Männistö M, Rönkkö S, Mättö M, Honkakoski P, Hyttinen M, Pelkonen J, Urtti A. The role of cell cycle on polyplex-mediated gene transfer into a retinal pigment epithelial cell line. J Gene Med 2004; 7:466-76. [PMID: 15619286 DOI: 10.1002/jgm.693] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Retinal pigment epithelium (RPE) maintains the function of photoreceptors and eyesight and is an important target for gene delivery. Since in some diseases RPE cells proliferate uncontrollably, we investigated the role of cell cycle in non-viral gene delivery into a RPE cell line (D407). METHODS D407 (human) cells were transfected with cationic DNA complexes. Cells were synchronized into different phases of the cell cycle and transfected using poly-L-lysine (PLL) or polyethyleneimine (PEI) carriers for 3 h. The effects of different reporters (beta-galactosidase, luciferase) or promoters (CMV, SV40, tk, PDE-beta) on gene expression were evaluated 43 h later. Cellular uptake of ethidium monoazide/DNA complexes with PLL or PEI was determined by flow cytometry. Fluorescent DNA and the complexes were localized with a confocal microscope. The role of cell cycle in transcription was evaluated by stable luciferase-expressing cells. RESULTS PLL showed lower transfection levels than PEI in synchronized cells and only slight dependence on cell cycle. PEI showed minimal efficiency at G1 phase and maximum level at S phase. All promoters and reporter genes showed dependence on cell cycle. Cellular uptake of polyplexes was highest at S phase (80-90%) and lowest at G1 phase (5-30%). Confocal microscopy showed minor differences of free DNA between groups in the nucleus, where it was largely carrier-bound. Cell cycle effects on luciferase expression were clear in stable cell line CONCLUSIONS Transfection by polyplexes in the RPE cell line is influenced by cellular uptake and transcription, and both processes are cell-cycle-dependent. The results have implications in retinal gene therapy.
Collapse
Affiliation(s)
- Marjo Männistö
- Department of Pharmaceutics, University of Kuopio, P.O. Box 1627, 70211 Kuopio, Finland.
| | | | | | | | | | | | | |
Collapse
|
247
|
Suh J, Wirtz D, Hanes J. Real-time intracellular transport of gene nanocarriers studied by multiple particle tracking. Biotechnol Prog 2004; 20:598-602. [PMID: 15059007 DOI: 10.1021/bp034251y] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We used real-time multiple particle tracking to quantitatively characterize the type and rates of transport of gene nanocarriers within live cells. The heterogeneous cytoplasmic transport of polyethylenimine (PEI)/DNA gene carriers was quantified by tracking their mean-square displacements over time and classified into active and nonactive transport populations on the basis of their effective diffusivities versus time. Nonactive gene carriers frequently displayed hop-diffusion trajectories, suggesting a porous cytoplasmic network of flexible biopolymers or sequential attachment and detachment events. Microtubule-dependent active transport of gene carriers resulted in an effective diffusivity 30-fold greater than that of nonactive carriers (at a time scale of 3 s). Compared to nonactive carriers in control cells with intact microtubules, microtubule depolymerization enhanced short-range motion of gene carriers but resulted in similar long-range transport. Multiple particle tracking characterizes gene carrier transport in complex biological environments and, therefore, may be a useful tool in quantifying rate-limiting steps in gene delivery within cells and other biological media.
Collapse
Affiliation(s)
- Junghae Suh
- Department of Biomedical Engineering, The Johns Hopkins University, 720 Rutland Ave., Baltimore, Maryland 21205, USA
| | | | | |
Collapse
|
248
|
Robinson DA, Bremner SN, Sethi K, Shah SB, Sirsi SR, Lutz GJ. In vivo expression of myosin essential light chain using plasmid expression vectors in regenerating frog skeletal muscle. Gene Ther 2004; 12:347-57. [PMID: 15538392 DOI: 10.1038/sj.gt.3302411] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
It is well established that mutations in specific structural elements of the motor protein myosin are directly linked to debilitating diseases involving malfunctioning striated muscle cells. A potential way to study the relationship between myosin structure and function is to express exogenous myosin in vivo and determine contractile properties of the transgenic muscle cells. However, in vivo expression of functional levels of contractile proteins using transient transgenesis in skeletal muscle has not been demonstrated. Presently, we used in vivo gene transfer to express high levels of full-length myosin light chain (MLC) in skeletal muscle fibers of Rana pipiens. Anterior tibialis (AT) muscles were injected with cardiotoxin to cause degeneration and then injected at various stages of regeneration with plasmid expression vectors encoding full-length MLC1(f). In fibers from the most robustly transfected muscles 3 weeks after plasmid injections, trans-MLC1(f) expression averaged 22-43% of the endogenous MLC1(f). Trans-MLC1(f) expression was the same whether a small epitope tag was placed on the C- or N-terminus and was highly variable along individual fibers. Confocal microscopy of skinned fibers showed correct sarcomeric incorporation of trans-MLC1(f). The expression profile of myosin heavy chain isoforms 21 days after transfection was similar to normal AT muscle. These data demonstrate the feasibility of using in vivo gene transfer to probe the structural basis of contractile protein function in skeletal muscle. Based on these promising results, we discuss how further improvements in the level and consistency of myosin transgene expression may be achieved in future studies, and the therapeutic potential of plasmid gene transfer in regenerating muscle.
Collapse
Affiliation(s)
- D A Robinson
- University of California San Diego and Veterans Affairs Medical Center, San Diego, CA, USA
| | | | | | | | | | | |
Collapse
|
249
|
Dubruel P, Christiaens B, Rosseneu M, Vandekerckhove J, Grooten J, Goossens V, Schacht E. Buffering properties of cationic polymethacrylates are not the only key to successful gene delivery. Biomacromolecules 2004; 5:379-88. [PMID: 15002997 DOI: 10.1021/bm034438d] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recently, we have shown that polymethacrylates containing imidazole side groups (HYMIMMA) or acid functions (MA), which have similar buffering properties as polyethyleneimine, were not able to transfect Cos-1 cells, whereas polymers containing only tertiary amines (DMAEMA) do transfect Cos-1 cells (Dubruel, P. et al. Eur. J. Pharm. Sci. 2003, 18 (3-4), 211-220). In the present work, we investigated to what extent the differences in transfection activity are related to differences in cellular internalization and/or subcellular localization. Therefore, we synthesized a series of polymethacrylates containing primary amine functions, used for the coupling of the fluorescent Oregon Green probe. The polymers containing acid functions were labeled with an amine containing fluorescein derivative (5-aminomethyl)fluorescein hydrochloride. It is demonstrated that the endosomal release of the MA and HYMIMMA-based complexes might be the limiting step in the gene transfer process in Cos-1 cells.
Collapse
Affiliation(s)
- Peter Dubruel
- Polymer Materials Research Group, Department of Organic Chemistry, Ghent University, Ghent, Belgium
| | | | | | | | | | | | | |
Collapse
|
250
|
Roth CM, Sundaram S. Engineering synthetic vectors for improved DNA delivery: insights from intracellular pathways. Annu Rev Biomed Eng 2004; 6:397-426. [PMID: 15255775 DOI: 10.1146/annurev.bioeng.6.040803.140203] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Significant progress has been made in the area of nonviral gene delivery to date. Yet, synthetic vectors remain less efficient by orders of magnitude than their viral counterparts. Research continues toward unraveling and overcoming various barriers to the efficient delivery of DNA, whether in plasmid form encoding a gene or as an oligonucleotide for the selective inhibition of target gene expression. Novel components for overcoming these hurdles are continually being incorporated into the design of synthetic vectors, leading to increasingly more virus-like particles. Despite these advances, general principles defining the design of synthetic vectors are yet to be developed fully. A more quantitative analysis of the cellular uptake and intracellular processing of these vectors is required for the rational manipulation of vector design. Mathematical frameworks with a more conceptual basis will help obtain an integrated perspective on these complex systems. In this review, we critically examine the progress made toward the improved design of synthetic vectors by the strategic exploitation of intracellular mechanisms and explore newer possibilities to overcome obstacles in the practical realization of this field.
Collapse
Affiliation(s)
- Charles M Roth
- Department of Chemical and Biochemical Engineering, Rutgers University, Piscataway, New Jersey 08854, USA.
| | | |
Collapse
|