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Recent advances in peptide-targeted micelleplexes: Current developments and future perspectives. Int J Pharm 2021; 597:120362. [PMID: 33556489 DOI: 10.1016/j.ijpharm.2021.120362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 01/27/2021] [Accepted: 02/03/2021] [Indexed: 12/11/2022]
Abstract
The decoding of the human genome revolutionized the understanding of how genetics influence the interplay between health and disease, in a multidisciplinary perspective. Thus, the development of exogenous nucleic acids-based therapies has increased to overcome hereditary or acquired genetic-associated diseases. Gene drug delivery using non-viral systems, for instance micelleplexes, have been recognized as promising options for gene-target therapies. Micelleplexes are core-shell structures, at a nanometric scale, designed using amphiphilic block copolymers. These can self-assemble in an aqueous medium, leading to the formation of a hydrophilic and positively charged corona - that can transport nucleic acids, - and a hydrophobic core - which can transport poor water-soluble drugs. However, the performance of these types of carriers usually is hindered by several in vivo barriers. Fortunately, due to a significant amount of research, strategies to overcome these shortcomings emerged. With a wide range of structural features, good stability against proteolytic degradation, affordable characteristic, easy synthesis, low immunogenicity, among other advantages, peptides have increasingly gained popularity as target ligands for non-viral carriers. Hence, this review addresses the use of peptides with micelleplexes illustrating, through the analysis of in vitro and in vivo studies, the potential and future perspectives of this combination.
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Pieńko T, Czarnecki J, Równicki M, Wojciechowska M, Wierzba AJ, Gryko D, Bartosik D, Trylska J. Vitamin B 12-peptide nucleic acids use the BtuB receptor to pass through the Escherichia coli outer membrane. Biophys J 2021; 120:725-737. [PMID: 33453274 DOI: 10.1016/j.bpj.2021.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 12/30/2020] [Accepted: 01/07/2021] [Indexed: 12/11/2022] Open
Abstract
Short modified oligonucleotides that bind in a sequence-specific way to messenger RNA essential for bacterial growth could be useful to fight bacterial infections. One such promising oligonucleotide is peptide nucleic acid (PNA), a synthetic DNA analog with a peptide-like backbone. However, the limitation precluding the use of oligonucleotides, including PNA, is that bacteria do not import them from the environment. We have shown that vitamin B12, which most bacteria need to take up for growth, delivers PNAs to Escherichia coli cells when covalently linked with PNAs. Vitamin B12 enters E. coli via a TonB-dependent transport system and is recognized by the outer-membrane vitamin B12-specific BtuB receptor. We engineered the E. coli ΔbtuB mutant and found that transport of the vitamin B12-PNA conjugate requires BtuB. Thus, the conjugate follows the same route through the outer membrane as taken by free vitamin B12. From enhanced sampling all-atom molecular dynamics simulations, we determined the mechanism of conjugate permeation through BtuB. BtuB is a β-barrel occluded by its luminal domain. The potential of mean force shows that conjugate passage is unidirectional and its movement into the BtuB β-barrel is energetically favorable upon luminal domain unfolding. Inside BtuB, PNA extends making its permeation mechanically feasible. BtuB extracellular loops are actively involved in transport through an induced-fit mechanism. We prove that the vitamin B12 transport system can be hijacked to enable PNA delivery to E. coli cells.
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Affiliation(s)
- Tomasz Pieńko
- Centre of New Technologies, University of Warsaw, Warsaw, Poland; Department of Drug Chemistry, Faculty of Pharmacy with the Laboratory Medicine Division, Medical University of Warsaw, Warsaw, Poland.
| | - Jakub Czarnecki
- Faculty of Biology, University of Warsaw, Warsaw, Poland; Bacterial Genome Plasticity, Department of Genomes and Genetics, Institut Pasteur, Paris, France
| | - Marcin Równicki
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | | | | | - Dorota Gryko
- Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | | | - Joanna Trylska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland.
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Kozisek T, Hamann A, Nguyen A, Miller M, Plautz S, Pannier AK. High-throughput screening of clinically approved drugs that prime nonviral gene delivery to human Mesenchymal stem cells. J Biol Eng 2020; 14:16. [PMID: 32467728 PMCID: PMC7238544 DOI: 10.1186/s13036-020-00238-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 05/04/2020] [Indexed: 01/07/2023] Open
Abstract
Background Human mesenchymal stem cells (hMSCs) are intensely researched for applications in cell therapeutics due to their unique properties, however, intrinsic therapeutic properties of hMSCs could be enhanced by genetic modification. Viral transduction is efficient, but suffers from safety issues. Conversely, nonviral gene delivery, while safer compared to viral, suffers from inefficiency and cytotoxicity, especially in hMSCs. To address the shortcomings of nonviral gene delivery to hMSCs, our lab has previously demonstrated that pharmacological 'priming' of hMSCs with the glucocorticoid dexamethasone can significantly increase transfection in hMSCs by modulating transfection-induced cytotoxicity. This work seeks to establish a library of transfection priming compounds for hMSCs by screening 707 FDA-approved drugs, belonging to diverse drug classes, from the NIH Clinical Collection at four concentrations for their ability to modulate nonviral gene delivery to adipose-derived hMSCs from two human donors. Results Microscope images of cells transfected with a fluorescent transgene were analyzed in order to identify compounds that significantly affected hMSC transfection without significant toxicity. Compound classes that increased transfection across both donors included glucocorticoids, antibiotics, and antihypertensives. Notably, clobetasol propionate, a glucocorticoid, increased transgene production 18-fold over unprimed transfection. Furthermore, compound classes that decreased transfection across both donors included flavonoids, antibiotics, and antihypertensives, with the flavonoid epigallocatechin gallate decreasing transgene production - 41-fold compared to unprimed transfection. Conclusions Our screen of the NCC is the first high-throughput and drug-repurposing approach to identify nonviral gene delivery priming compounds in two donors of hMSCs. Priming compounds and classes identified in this screen suggest that modulation of proliferation, mitochondrial function, and apoptosis is vital for enhancing nonviral gene delivery to hMSCs.
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Affiliation(s)
- Tyler Kozisek
- 1Department of Biological Systems Engineering, University of Nebraska-Lincoln, 231 L.W. Chase Hall, Lincoln, NE USA
| | - Andrew Hamann
- 1Department of Biological Systems Engineering, University of Nebraska-Lincoln, 231 L.W. Chase Hall, Lincoln, NE USA
| | - Albert Nguyen
- 1Department of Biological Systems Engineering, University of Nebraska-Lincoln, 231 L.W. Chase Hall, Lincoln, NE USA
| | - Michael Miller
- 2Department of Biomedical Engineering, Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA USA
| | - Sarah Plautz
- 1Department of Biological Systems Engineering, University of Nebraska-Lincoln, 231 L.W. Chase Hall, Lincoln, NE USA
| | - Angela K Pannier
- 1Department of Biological Systems Engineering, University of Nebraska-Lincoln, 231 L.W. Chase Hall, Lincoln, NE USA
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Cytoplasmic transport and nuclear import of plasmid DNA. Biosci Rep 2017; 37:BSR20160616. [PMID: 29054961 PMCID: PMC5705778 DOI: 10.1042/bsr20160616] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 10/13/2017] [Accepted: 10/17/2017] [Indexed: 01/04/2023] Open
Abstract
Productive transfection and gene transfer require not simply the entry of DNA into cells and subsequent transcription from an appropriate promoter, but also a number of intracellular events that allow the DNA to move from the extracellular surface of the cell into and through the cytoplasm, and ultimately across the nuclear envelope and into the nucleus before any transcription can initiate. Immediately upon entry into the cytoplasm, naked DNA, either delivered through physical techniques or after disassembly of DNA-carrier complexes, associates with a large number of cellular proteins that mediate subsequent interactions with the microtubule network for movement toward the microtubule organizing center and the nuclear envelope. Plasmids then enter the nucleus either upon the mitotic disassembly of the nuclear envelope or through nuclear pore complexes in the absence of cell division, using a different set of proteins. This review will discuss our current understanding of these pathways used by naked DNA during the transfection process. While much has been elucidated on these processes, much remains to be discerned, but with the development of a number of model systems and approaches, great progress is being made.
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Zhou Z, Liu X, Zhu D, Wang Y, Zhang Z, Zhou X, Qiu N, Chen X, Shen Y. Nonviral cancer gene therapy: Delivery cascade and vector nanoproperty integration. Adv Drug Deliv Rev 2017; 115:115-154. [PMID: 28778715 DOI: 10.1016/j.addr.2017.07.021] [Citation(s) in RCA: 269] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 07/25/2017] [Accepted: 07/27/2017] [Indexed: 02/07/2023]
Abstract
Gene therapy represents a promising cancer treatment featuring high efficacy and limited side effects, but it is stymied by a lack of safe and efficient gene-delivery vectors. Cationic polymers and lipid-based nonviral gene vectors have many advantages and have been extensively explored for cancer gene delivery, but their low gene-expression efficiencies relative to viral vectors limit their clinical translations. Great efforts have thus been devoted to developing new carrier materials and fabricating functional vectors aimed at improving gene expression, but the overall efficiencies are still more or less at the same level. This review analyzes the cancer gene-delivery cascade and the barriers, the needed nanoproperties and the current strategies for overcoming these barriers, and outlines PEGylation, surface-charge, size, and stability dilemmas in vector nanoproperties to efficiently accomplish the cancer gene-delivery cascade. Stability, surface, and size transitions (3S Transitions) are proposed to resolve those dilemmas and strategies to realize these transitions are comprehensively summarized. The review concludes with a discussion of the future research directions to design high-performance nonviral gene vectors.
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Affiliation(s)
- Zhuxian Zhou
- Center for Bionanoengineering and Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Zheda Road 38, 310027 Hangzhou, China
| | - Xiangrui Liu
- Center for Bionanoengineering and Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Zheda Road 38, 310027 Hangzhou, China
| | - Dingcheng Zhu
- Center for Bionanoengineering and Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Zheda Road 38, 310027 Hangzhou, China
| | - Yue Wang
- Center for Bionanoengineering and Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Zheda Road 38, 310027 Hangzhou, China
| | - Zhen Zhang
- Center for Bionanoengineering and Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Zheda Road 38, 310027 Hangzhou, China
| | - Xuefei Zhou
- Center for Bionanoengineering and Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Zheda Road 38, 310027 Hangzhou, China
| | - Nasha Qiu
- Center for Bionanoengineering and Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Zheda Road 38, 310027 Hangzhou, China
| | - Xuesi Chen
- Changchun Institute of Applied Chemistry, Key Lab of Polymer Ecomaterials, Changchun, China
| | - Youqing Shen
- Center for Bionanoengineering and Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Zheda Road 38, 310027 Hangzhou, China.
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Pieńko T, Wierzba AJ, Wojciechowska M, Gryko D, Trylska J. Conformational Dynamics of Cyanocobalamin and Its Conjugates with Peptide Nucleic Acids. J Phys Chem B 2017; 121:2968-2979. [PMID: 28301169 DOI: 10.1021/acs.jpcb.7b00649] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Vitamin B12 also called cobalamin (Cbl) is an important enzymatic cofactor taken up by mammalian and also by many bacterial cells. Peptide nucleic acid (PNA) is a synthetic DNA analogue that has the ability to bind in a complementary manner to natural nucleic acids. Provided that PNA is efficiently delivered to cells, it could act as a steric blocker of functional DNA or RNA and regulate gene expression at the level of transcription or translation. Recently, Cbl has been examined as a transporter of various molecules to cells. Also, PNA, if covalently linked with Cbl, can be delivered to bacterial cells, but it is crucial to verify that Cbl does not change the desired PNA biological properties. We have analyzed the structure and conformational dynamics of conjugates of Cbl with a PNA monomer and oligomer. We synthesized a cyanocobalamin derivative with a PNA monomer C connected via the triazole linker and determined its NMR spectra. Using microsecond-long molecular dynamics simulations, we examined the internal dynamics of cyanocobalamin-C, its conjugate with a 14-mer PNA, and free PNA. The results suggest that all compounds acquire rather compact structures but the PNA oligomer conformations vary. For the Cbl-C conjugate the cross-peaks from the ROESY spectrum corroborated with the clusters from molecular dynamics trajectories. Within PNA the dominant interaction is stacking but the stacking bases are not necessarily neighboring in the PNA sequence. More bases stack in free PNA than in PNA of the conjugate, but stacking is less stable in free PNA. PNA in the conjugate is slightly more exposed to solvent. Overall, cyanocobalamin attached to a PNA oligomer increases the flexibility of PNA in a way that could be beneficial for its hybridization with natural nucleic acid oligomers.
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Affiliation(s)
- Tomasz Pieńko
- Centre of New Technologies, University of Warsaw , S. Banacha 2c, 02-097 Warsaw, Poland.,Department of Drug Chemistry, Faculty of Pharmacy with the Laboratory Medicine Division, Medical University of Warsaw , S. Banacha 1a, 02-097 Warsaw, Poland
| | - Aleksandra J Wierzba
- Institute of Organic Chemistry, Polish Academy of Sciences , M. Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Monika Wojciechowska
- Centre of New Technologies, University of Warsaw , S. Banacha 2c, 02-097 Warsaw, Poland
| | - Dorota Gryko
- Institute of Organic Chemistry, Polish Academy of Sciences , M. Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Joanna Trylska
- Centre of New Technologies, University of Warsaw , S. Banacha 2c, 02-097 Warsaw, Poland
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Watanabe T, Hoshida T, Sakyo J, Kishi M, Tanabe S, Matsuura J, Akiyama S, Nakata M, Tanabe Y, Suzuki AZ, Watanabe S, Furuta T. Synthesis of nucleobase-caged peptide nucleic acids having improved photochemical properties. Org Biomol Chem 2015; 12:5089-93. [PMID: 24921960 DOI: 10.1039/c4ob00418c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A nucleobase-caged peptide nucleic acid (PNA) having a (6-bromo-7-methoxycoumarin)-4-ylmethoxycarbonyl (Bmcmoc) caging group was newly synthesized. The Bmcmoc-caged PNAs were photolyzed to produce parent PNAs with a high photochemical efficiency. Introduction of a single Bmcmoc group was sufficient to suppress polymerase chain reaction (PCR) clamping activity and triplex invasion complex formation. Photo-mediated restoration of the PCR clamping activity was also demonstrated.
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Affiliation(s)
- Takayoshi Watanabe
- Department of Biomolecular Science, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
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Mishra D, Kang HC, Cho H, Bae YH. Dexamethasone-loaded reconstitutable charged polymeric (PLGA)n -b-bPEI micelles for enhanced nuclear delivery of gene therapeutics. Macromol Biosci 2014; 14:831-41. [PMID: 24550091 DOI: 10.1002/mabi.201300432] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 01/09/2014] [Indexed: 11/06/2022]
Abstract
This study investigates the potential of dexamethasone (Dex) to enhance the nuclear accumulation and subsequent gene expression of plasmid DNA (pDNA) delivered using a charged polymeric micelle-based gene delivery system. (PLGA)n -b-bPEI25kDa block copolymers are synthesized and used to prepare Dex-loaded cationic micelles (DexCM). After preparing DexCM/pDNA complexes, bPEI1.8kDa is coated on the complexes using a Layer-by-Layer (LbL) technique to construct DexCM/pDNA/bPEI1.8kDa complexes (i.e., LbL-DexCM polyplexes) that are 100-180 nm in diameter and have a zeta potential of 30-40 mV. In MCF7 cells, LbL-DexCM polyplexes cause 3-13-fold higher transfection efficiencies compared to LbL-CM polyplexes and show negligible cytotoxicity. LbL-DexCM3 polyplexes induce much higher nuclear delivery of pDNA compared to LbL-CM3 polyplexes. These results suggest that Dex-loaded polyplexes could be used in gene and drug delivery applications to increase nuclear accumulation of therapeutic payloads, further leading to a decrease in the dose of the drug and gene necessary to achieve equivalent therapeutic effects.
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Affiliation(s)
- Deepa Mishra
- Department of Bioengineering, The University of Utah, 20 S. 2030 E., Rm. 108, Salt Lake City, Utah, 84112, USA
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Bezuidenhout D, Oosthuysen A, Davies N, Ahrenstedt L, Dobner S, Roberts P, Zilla P. Covalent incorporation and controlled release of active dexamethasone from injectable polyethylene glycol hydrogels. J Biomed Mater Res A 2012; 101:1311-8. [DOI: 10.1002/jbm.a.34438] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 08/06/2012] [Accepted: 08/29/2012] [Indexed: 11/10/2022]
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Kang HC, Huh KM, Bae YH. Polymeric nucleic acid carriers: current issues and novel design approaches. J Control Release 2012; 164:256-64. [PMID: 22771981 DOI: 10.1016/j.jconrel.2012.06.036] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 06/25/2012] [Accepted: 06/27/2012] [Indexed: 11/26/2022]
Abstract
To deliver nucleic acids including plasmid DNA (pDNA) and short interfering RNA (siRNA), polymeric gene carriers equipped with various functionalities have been extensively investigated. The functionalities of these polymeric vectors have been designed to overcome various extracellular and intracellular hurdles that nucleic acids and their carriers encounter during their journey from injection site to intracellular target site. This review briefly introduces known extracellular and intracellular issues of nucleic acid delivery and their solution strategies. We examine significant yet overlooked factors affecting nucleic acid delivery (e.g., microenvironmental pH, polymer/siRNA complexation, and pharmaceutical formulation) and highlight our reported approaches to solve these problems.
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Affiliation(s)
- Han Chang Kang
- Department of Pharmacy and Integrated Research Institute of Pharmaceutical Sciences, College of Pharmacy, The Catholic University of Korea, 43 Jibong-ro, Wonmi-gu, Bucheon-si, Gyeonggi-do 420-743, Republic of Korea
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Ma K, Shen H, Shen S, Xie M, Mao C, Qiu L, Jin Y. Development of a successive targeting liposome with multi-ligand for efficient targeting gene delivery. J Gene Med 2011; 13:290-301. [PMID: 21574214 DOI: 10.1002/jgm.1569] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND A successful gene delivery system needs to breakthrough several barriers to allow efficient transgenic expression. In the present study, successive targeting liposomes (STL) were constructed by integrating various targeting groups into a nanoparticle to address this issue. METHODS Polyethylenimine (PEI) 1800-triamcinolone acetonide (TA) with nuclear targeting capability was synthesized by a two-step reaction. Lactobionic acid was connected with cholesterol to obtain a compound of [(2-lactoylamido) ethylamino]formic acid cholesterol ester (CHEDLA) with hepatocyte-targeting capability. The liposome was modified with PEI 1800-TA and CHEDLA to prepare successive targeting liposome (STL). Its physicochemical properties and transfection efficiency were investigated both in vitro and in vivo. RESULTS The diameter of STL was approximately 100 nm with 20 mV of potential. The confocal microscopy observation and potential assay verified that lipid bilayer of STL was decorated with PEI 1800-TA. Cytotoxicity of STL was significantly lower than that of PEI 1800-TA and PEI 25K. The transfection efficiency of 10% CHEDLA STL in HepG2 cells was the higher than of the latter two with serum. Its transfection efficiency was greatly reduced with excessive free galactose, indicating that STL was absorbed via galactose receptor-mediated endocytosis. The in vivo study in mice showed that 10% CHEDLA STL had better transgenic expression in liver than the other carriers. CONCLUSIONS STL with multi-ligand was able to overcome the various barriers to target nucleus and special cells and present distinctive transgenic expression. Therefore, it has a great potential for gene therapy as a nonviral carrier.
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Affiliation(s)
- Kun Ma
- Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
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Ma K, Hu M, Xie M, Shen H, Qiu L, Fan W, Sun H, Chen S, Jin Y. Investigation of polyethylenimine-grafted-triamcinolone acetonide as nucleus-targeting gene delivery systems. J Gene Med 2010; 12:669-80. [PMID: 20635325 DOI: 10.1002/jgm.1485] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Nuclear membrane is one of the main barriers in polymer mediated intracellular gene delivery. To improve the transgenic activity and safety of nonviral vector, triamcinolone acetonide (TA) as a nuclear localization signal was conjugated with different molecular weight polyethylenimine (PEI). METHODS Different molecular weight PEI [600, 1800, 25,000 (25k)] was conjugated with TA to synthesize PEI-TA by two-step reaction. Their physicochemical characteristics, in vitro cytotoxicity and transfection efficiency were evaluated. To investigate the difference of transfection efficiency of various molecular weight PEI-TA, their transfection mechanism was further investigated by confocal microscopy and competition assay. Transgenic expression in vivo was evaluated by injection into hepatic portal vein of mice. RESULTS All PEI-TA could form nanosize polyplexes with DNA and their physicochemical properties resemble each other. Their cytotoxicities were negligible compared to PEI 25k. The order of transfection efficiency was PEI 1800-TA > PEI 600-TA > PEI 25k-TA. A transfection mechanism study displayed that TA could inhibit considerably the transgenic activity of PEI 1800-TA and PEI 600-TA, but that of PEI 25k-TA was not inhibited. It was suggested that PEI 1800-TA and PEI 600-TA might translocate into the nucleus. Confocal microscopy investigation verified this suggestion. The data strongly suggested that the transfection efficiency of PEI 1800-TA in vivo was much higher than that of PEI 25k, which was consistent with the results obtained in vitro. CONCLUSIONS Low molecular weight PEI-TA could translocate into the nucleus efficiently. PEI 1800-TA presented higher transgenic activity and it has a great potential for gene therapy as a nonviral carrier.
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Affiliation(s)
- Kun Ma
- Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, PR China
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Temperature-assisted cyclic hybridization (TACH): an improved method for supercoiled DNA hybridization. Mol Biotechnol 2010; 45:171-9. [PMID: 20238183 DOI: 10.1007/s12033-010-9261-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Accurate hybridization is dependent on the ratio between sequence-specific and unspecific binding. Dissociation of unspecifically bound, while maintaining specifically hybridized, nucleic acids are key steps to obtain a well-defined complex. We have developed a new method, temperature-assisted, cyclic hybridization (TACH), which increases cognate binding at the expense of unspecific hybridization. The method was used for optimizing binding of peptide nucleic acid (PNA) to supercoiled plasmids and has several advantages over previous methods: (1) it reduces the required amount of bis-PNA by three- to fourfold; (2) it results in less unspecific binding; (3) it extends cooperative hybridization, from 3 bp to 5 bp between two adjacent binding sites; and (4) it decreases the aggregation of bis-PNA. This method might be extended to other forms of hybridizations including the use of additional nucleic acids analogs, such as locked nucleic acid (LNA) and, also, to other areas where PNAs are used such as fluorescence in situ hybridization (FISH), microarrays, or in vivo plasmid delivery.
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Roviello GN, Benedetti E, Pedone C, Bucci EM. Nucleobase-containing peptides: an overview of their characteristic features and applications. Amino Acids 2010; 39:45-57. [PMID: 20349320 DOI: 10.1007/s00726-010-0567-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2010] [Accepted: 03/11/2010] [Indexed: 11/26/2022]
Abstract
Reports on nucleobase-containing chiral peptides (both natural and artificial) and achiral pseudopeptides are reviewed. Their synthesis, structural features, DNA and RNA-binding ability, as well as some other interesting applications which make them promising diagnostic/therapeutic agents of great importance in many areas of biology and therapy are taken into critical consideration.
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Affiliation(s)
- Giovanni N Roviello
- Istituto di Biostrutture e Bioimmagini, Consiglio Nazionale delle Ricerche, Via Mezzocannone 16, 80134, Naples, Italy
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Ma K, Hu MX, Qi Y, Zou JH, Qiu LY, Jin Y, Ying XY, Sun HY. PAMAM-triamcinolone acetonide conjugate as a nucleus-targeting gene carrier for enhanced transfer activity. Biomaterials 2009; 30:6109-18. [PMID: 19656564 DOI: 10.1016/j.biomaterials.2009.07.036] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Accepted: 07/17/2009] [Indexed: 11/29/2022]
Abstract
The excellent transfection efficiency and viability are essential for successful gene therapy. It suggested that when bound to its glucocorticoid receptor, glucocorticoid steroid can dilate the nuclear pore complexes and facilitated the transport of pDNA into the nucleus. In this research, the two different degrees of substitution of PAMAM-triamcinolone acetonide (PAMAM-TA) conjugates were synthesised for efficient translocation of pDNA into the nucleus. The physicochemical properties of the polyplexes were investigated by agarose gel electrophoresis, Zeta-sizer and TEM. They both could form nano-size polyplexes with pDNA. The polyplexes were very stable and showed excellent buffering capacities, facilitating endosomal escape, and no obvious difference was found between them. The TA-conjugated PAMAM-mediated transfection of luciferase and EGFP genes showed better transfer activity than native PAMAM and was comparable to the PEI 25K (polyethylenimine), and lower cytotoxicity in HEK 293 and HepG 2 cells. Even with 10% serum, their transfer activity was still high relatively. In addition, confocal microscopy examination confirmed that the enhancing mechanism for enhanced gene transfer activity of PAMAM-TA conjugate may involve the nuclear translocation of the polyplex. The low substituted degree of TA to 0.22 did not interrupt its nuclear localization potency. These findings demonstrated that the TA-grafted PAMAM dendrimer is a potential candidate as a safe and efficient gene delivery carrier for gene therapy.
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Affiliation(s)
- Kun Ma
- Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, PR China
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Miller AM, Dean DA. Tissue-specific and transcription factor-mediated nuclear entry of DNA. Adv Drug Deliv Rev 2009; 61:603-13. [PMID: 19393704 DOI: 10.1016/j.addr.2009.02.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2008] [Accepted: 02/05/2009] [Indexed: 12/22/2022]
Abstract
Low levels of gene transfer and a lack of tissue-specific targeting of vectors have limited the therapeutic potential of non-viral gene therapy. This is due to the numerous cellular barriers that hinder nuclear delivery of vectors and the paucity of methods that restrict expression to specific cells types. In non-dividing cells, the nuclear envelope is an especially problematic hurdle to gene transfer. Given that the majority of target tissues are non-dividing in vivo, the nuclear membrane is a major obstacle to therapeutic gene transfer. In this review, the various barriers to gene transfer are discussed. In particular, the role of the nuclear pore complex (NPC) in regulating passage of plasmid vectors during interphase is reviewed. Several methods of modifying plasmid (pDNA) vectors to enhance nuclear import through the NPC are also discussed, including the use of tissue-specific transcription factors to mediate nuclear entry of pDNA in a cell-specific manner.
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Affiliation(s)
- Aaron M Miller
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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18
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Ma K, Hu M, Qi Y, Qiu L, Jin Y, Yu J, Li B. Structure-transfection activity relationships with glucocorticoid-polyethyl-enimine conjugate nuclear gene delivery systems. Biomaterials 2009; 30:3780-9. [PMID: 19375793 DOI: 10.1016/j.biomaterials.2009.03.042] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Accepted: 03/17/2009] [Indexed: 11/30/2022]
Abstract
Efficient nuclear gene delivery is essential for successful gene therapy. It was previously reported that the transport of DNA into nucleus may be facilitated by glucocorticoid (GC). In this study, five glucocorticoids with different structures and potencies were conjugated with low molecular weight PEI 1800, and the degree of substitution of glucocorticoids was controlled to be close to each other. The glucocorticoid-polyethylenimine (GC-PEI)/pDNA complexes were prepared and their physico-chemical properties and transfection efficiency were investigated. The results showed that the complexes had similar physico-chemical properties, but their transfection activities were different statistically. In order to explore the reason of this difference, the affinity of GC-PEI polymer with GC receptor was analyzed by the application of molecular docking, and the correlation between transfection activity and the potency of five GC was investigated. The result showed that receptor binding of five GC was different and transgene expression enhanced linearly with the increasing GC potency, but logP. In addition, confocal microscopy examination confirmed that GC-PEI/DNA complexes were more effectively translocated in the nucleus than PEI 25K or PEI 1800 complexes and the cytotoxicities of the GC-PEI polymers were lower than that of PEI 25K. These results demonstrated that transfection activity of GC-PEI polymer correlated with its GC potency, and this regularity might be useful for the development of more efficient GC substituted polymer as promising nuclear-targeting carrier.
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Affiliation(s)
- Kun Ma
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
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19
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Mi Bae Y, Choi H, Lee S, Ho Kang S, Tae Kim Y, Nam K, Sang Park J, Lee M, Sig Choi J. Dexamethasone-conjugated low molecular weight polyethylenimine as a nucleus-targeting lipopolymer gene carrier. Bioconjug Chem 2007; 18:2029-36. [PMID: 17850108 DOI: 10.1021/bc070012a] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dexamethasone, a glucocorticoid steroid, can dilate the nuclear pore complexes and translocate into the nucleus when it is bound to its glucocorticoid receptor, suggesting that the transport of DNA into the nucleus may be facilitated by the reagent. In this research, dexamethasone was conjugated to low molecular weight polyethylenimine (2 kDa) for efficient translocation of the polymer/DNA complex into the nucleus. Polyethylenimine (PEI)-dexamethasone (PEI-Dexa) was synthesized by one-step reaction using the Traut's reagent. In gel retardation assay, the PEI-Dexa/DNA complex was completely retarded at or above 0.3/1 weight ratio (polymer/DNA). The average size distributions and zeta-potential values of the complexes were measured at various weight ratios. In vitro transfection assay showed that the PEI-Dexa/DNA complex had higher gene delivery efficiency compared to PEI 2kDa/DNA complex. The localization of PEI-Dexa/plasmid DNA complexes in the nucleus was confirmed by using total internal reflection fluorescence and Nomarski differential interference contrast microscope as well as confocal microscope. Therefore, with efficient nuclear translocation and low cytotoxicity, PEI-Dexa may be useful for nonviral gene therapy.
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Affiliation(s)
- Yun Mi Bae
- Department of Biochemistry, Chungnam National University, Daejeon, Korea
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20
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Wagstaff KM, Jans DA. Nucleocytoplasmic transport of DNA: enhancing non-viral gene transfer. Biochem J 2007; 406:185-202. [PMID: 17680778 DOI: 10.1042/bj20070505] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Gene therapy, the correction of dysfunctional or deleted genes by supplying the lacking component, has long been awaited as a means to permanently treat or reverse many genetic disorders. To achieve this, therapeutic DNA must be delivered to the nucleus of cells using a safe and efficient delivery vector. Although viral-based vectors have been utilized extensively due to their innate ability to deliver DNA to intact cells, safety considerations, such as pathogenicity, oncogenicity and the stimulation of an immunological response in the host, remain problematical. There has, however, been much progress in the development of safe non-viral gene-delivery vectors, although they remain less efficient than the viral counterparts. The major limitations of non-viral gene transfer reside in the fact that it must be tailored to overcome the intracellular barriers to DNA delivery that viruses already master, including the cellular and nuclear membranes. In particular, nuclear transport of the therapeutic DNA is known to be the rate-limiting step in the gene-delivery process. Despite this, much progress had been made in recent years in developing novel means to overcome these barriers and efficiently deliver DNA to the nuclei of intact cells. This review focuses on the nucleocytoplasmic delivery of DNA and mechanisms to enhance to non-viral-mediated gene transfer.
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Affiliation(s)
- Kylie M Wagstaff
- Nuclear Signalling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
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21
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Vaughan EE, DeGiulio JV, Dean DA. Intracellular trafficking of plasmids for gene therapy: mechanisms of cytoplasmic movement and nuclear import. Curr Gene Ther 2007; 6:671-681. [PMID: 17168698 PMCID: PMC4400175 DOI: 10.2174/156652306779010688] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Under physiologically relevant conditions, the levels of non-viral gene transfer are low at best. The reason for this is that many barriers exist for the efficient transfer of genes to cells, even before any gene expression can occur. While many transfection strategies focus on DNA condensation and overcoming the plasma membrane, events associated with the intracellular trafficking of the DNA complexes have not been as extensively studied. Once internalized, plasmids must travel potentially long distances through the cytoplasm to reach their next barrier, the nuclear envelope. This review summarizes the current progress on the cytoplasmic trafficking and nuclear transport of plasmids used for gene therapy applications. Both of these processes utilize specific and defined mechanisms to facilitate movement of DNA complexes through the cell. The continued elucidation and exploitation of these mechanisms will lead to improved strategies for transfection and successful gene therapy.
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Affiliation(s)
| | | | - David A. Dean
- Address correspondence to this author at the Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, 240 E. Huron Ave., McGaw M-300, Chicago IL 60611 USA; Tel: 312-503-3121; Fax: 312-908-4650;
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22
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Topham CM, Smith JC. Orientation preferences of backbone secondary amide functional groups in peptide nucleic acid complexes: quantum chemical calculations reveal an intrinsic preference of cationic D-amino acid-based chiral PNA analogues for the P-form. Biophys J 2006; 92:769-86. [PMID: 17071666 PMCID: PMC1779963 DOI: 10.1529/biophysj.105.079723] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Geometric descriptions of nonideal interresidue hydrogen bonding and backbone-base water bridging in the minor groove are established in terms of polyamide backbone carbonyl group orientation from analyses of residue junction conformers in experimentally determined peptide nucleic acid (PNA) complexes. Two types of interresidue hydrogen bonding are identified in PNA conformers in heteroduplexes with nucleic acids that adopt A-like basepair stacking. Quantum chemical calculations on the binding of a water molecule to an O2 base atom in glycine-based PNA thymine dimers indicate that junctions modeled with P-form backbone conformations are lower in energy than a dimer comprising the predominant conformation observed in A-like helices. It is further shown in model systems that PNA analogs based on D-lysine are better able to preorganize in a conformation exclusive to P-form helices than is glycine-based PNA. An intrinsic preference for this conformation is also exhibited by positively charged chiral PNA dimers carrying 3-amino-D-alanine or 4-aza-D-leucine residue units that provide for additional rigidity by side-chain hydrogen bonding to the backbone carbonyl oxygen. Structural modifications stabilizing P-form helices may obviate the need for large heterocycles to target DNA pyrimidine bases via PNA.DNA-PNA triplex formation. Quantum chemical modeling methods are used to propose candidate PNA Hoogsteen strand designs.
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Affiliation(s)
- Christopher M Topham
- Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique UMR 5089, Toulouse, France.
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23
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Gruegelsiepe H, Brandt O, Hartmann RK. Antisense inhibition of RNase P: mechanistic aspects and application to live bacteria. J Biol Chem 2006; 281:30613-20. [PMID: 16901906 DOI: 10.1074/jbc.m603346200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We explored bacterial RNase P as a drug target using antisense oligomers against the P15 loop region of Escherichia coli RNase P RNA. An RNA 14-mer, or locked nucleic acid (LNA) and peptide nucleic acid (PNA) versions thereof, disrupted local secondary structure in the catalytic core, forming hybrid duplexes over their entire length. Binding of the PNA and LNA 14-mers to RNase P RNA in vitro was essentially irreversible and even resisted denaturing PAGE. Association rates for the RNA, LNA, and PNA 14-mers were approximately 10(5) m(-1) s(-1) with a rate advantage for PNA and were thus rather fast despite the need to disrupt local structure. Conjugates in which the PNA 14-mer was coupled to an invasive peptide via a novel monoglycine linker showed RNase P RNA-specific growth inhibition of E. coli cells. Cell growth could be rescued when expressing a second bacterial RNase P RNA with an unrelated sequence in the target region. We report here for the first time specific and growth-inhibitory drug targeting of RNase P in live bacteria. This is also the first example of a duplex-forming oligomer that invades a structured catalytic RNA and inactivates the RNA by (i) trapping it in a state in which the catalytic core is partially unfolded, (ii) sterically interfering with substrate binding, and (iii) perturbing the coordination of catalytically relevant Mg2+ ions.
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Affiliation(s)
- Heike Gruegelsiepe
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, D-35037 Marburg, Germany
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van Gaal EVB, Hennink WE, Crommelin DJA, Mastrobattista E. Plasmid engineering for controlled and sustained gene expression for nonviral gene therapy. Pharm Res 2006; 23:1053-74. [PMID: 16715361 DOI: 10.1007/s11095-006-0164-2] [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: 11/21/2005] [Accepted: 01/03/2006] [Indexed: 01/18/2023]
Abstract
Gene therapy requires the introduction of genetic material in diseased cells with the aim of treating or ultimately curing a disease. Since the start of gene therapy clinical trials in 1990, gene therapy has proven to be possible, but studies to date have highlighted the difficulty of achieving efficient, specific, and long-term transgene expression. Efforts to improve gene therapy strategies over the past years were mainly aimed at solving the problem of delivery, without paying much attention to the optimization of the expression cassette. With the current understanding of the eukaryotic transcription machinery and advanced molecular biology techniques at our disposition, it has now become possible to create custom-made transgene expression cassettes optimized for gene therapy applications. In this review, we will discuss several strategies that have been explored to improve the level and duration of transgene expression, to increase control over expression, or to restrict transgene expression to specific cell types or tissues. Although still in its infancy, such strategies will eventually lead to improvement of nonviral gene therapy and expansion of the range of possible therapeutic applications.
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Affiliation(s)
- Ethlinn V B van Gaal
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, P.O Box 80082, 3508 TB, Utrecht, The Netherlands
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25
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Kitamatsu M, Shigeyasu M, Saitoh M, Sisido M. Configurational preference of pyrrolidine-based oxy-peptide nucleic acids as hybridization counterparts with DNA and RNA. Biopolymers 2006; 84:267-73. [PMID: 16130130 DOI: 10.1002/bip.20364] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A new series of oxy-peptide nucleic acids (pyrrolidine-based oxy-peptide nucleic acids = POPNAs) of four different stereoisomeric forms (cis-L, cis-D, trans-L, trans-D) have been synthesized. To find a favorable stereoisomer of POPNA for hybridization with DNA or RNA, thermodynamic parameters and conformations of the hybrids between the four stereoisomers with 9 adenine bases [po(A(9))s] and dT(9) or rU(9) were investigated from ultraviolet (UV) melting curves and circular dichroism (CD) spectra. The cis-L-po(A(9)) formed the most stable hybrid with dT(9), because of the smallest entropy loss, despite the smallest enthalpy gain. In contrast, trans-L-po(A(9)) formed the most stable hybrid with rU(9), because of the largest enthalpy gain, despite the largest entropy loss. The hybrid stability of trans-L-po(A(9)) with rU(9) was significantly improved as compared with a previous version of oxy-peptide nucleic acid (OPNA) that lacks the pyrrolidine ring.
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Affiliation(s)
- Mizuki Kitamatsu
- Department of Bioscience and Biotechnology, Faculty of Engineering, Okayama University, Japan
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26
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Musumeci D, Valente M, Capasso D, Palumbo R, Görlach M, Schmidtke M, Zell R, Roviello GN, Sapio R, Pedone C, Bucci EM. A short PNA targeting coxsackievirus B3 5'-nontranslated region prevents virus-induced cytolysis. J Pept Sci 2006; 12:161-70. [PMID: 16121332 DOI: 10.1002/psc.708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Targeting regulatory RNA regions to interfere with the biosynthesis of a protein is an intriguing alternative to targeting a protein itself. Regulatory regions are often unique in sequence and/or structure and, thus, ideally suited for specific recognition with a low risk of undesired side effects. Targeting regulatory RNA elements, however, is complicated by their complex three-dimensional structure, which poses kinetic and thermodynamic constraints to the recognition by a complementary oligonucleotide. Oligonucleotide mimics, which shift the thermodynamic equilibrium towards complex formation and yield stable complexes with a target RNA, can overcome this problem. Peptide nucleic acids (PNA) represent such a promising class of molecules. PNA are very stable, non-ionic compounds and they are not sensitive to enzymatic degradation. Yet, PNA form specific base pairs with a target sequence. We have designed, synthesised and characterised PNA able to enter infected cells and to bind specifically to a control region of the genomic RNA of coxsackievirus B3 (CVB3), which is an important human pathogen. The results obtained by studying the interaction of such PNA with their RNA target, the entrance into the cell and the viral inhibition are herein presented.
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27
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van der Aa MAEM, Mastrobattista E, Oosting RS, Hennink WE, Koning GA, Crommelin DJA. The Nuclear Pore Complex: The Gateway to Successful Nonviral Gene Delivery. Pharm Res 2006; 23:447-59. [PMID: 16525863 DOI: 10.1007/s11095-005-9445-4] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Accepted: 11/10/2005] [Indexed: 02/04/2023]
Abstract
One of the limiting steps in the efficiency of nonviral gene delivery is transport of genetic material across the nuclear membrane. Trafficking of nuclear proteins from the cytoplasm into the nucleus occurs via the nuclear pore complex and is mediated by nuclear localization signals and their nuclear receptors. Several strategies employing this transport mechanism have been designed and explored to improve nonviral gene delivery. In this article, we review the mechanism of nuclear import through the nuclear pore complex and the strategies used to facilitate nuclear import of exogenous DNA and improve gene expression.
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Affiliation(s)
- Marieke 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
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28
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Lundin KE, Good L, Strömberg R, Gräslund A, Smith CIE. Biological activity and biotechnological aspects of peptide nucleic acid. ADVANCES IN GENETICS 2006; 56:1-51. [PMID: 16735154 DOI: 10.1016/s0065-2660(06)56001-8] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
During the latest decades a number of different nucleic acid analogs containing natural nucleobases on a modified backbone have been synthesized. An example of this is peptide nucleic acid (PNA), a DNA mimic with a noncyclic peptide-like backbone, which was first synthesized in 1991. Owing to its flexible and neutral backbone PNA displays very good hybridization properties also at low-ion concentrations and has subsequently attracted large interest both in biotechnology and biomedicine. Numerous modifications have been made, which could be of value for particular settings. However, the original PNA does so far perform well in many diverse applications. The high biostability makes it interesting for in vivo use, although the very limited diffusion over lipid membranes requires further modifications in order to make it suitable for treatment in eukaryotic cells. The possibility to use this nucleic acid analog for gene regulation and gene editing is discussed. Peptide nucleic acid is now also used for specific genetic detection in a number of diagnostic techniques, as well as for site-specific labeling and hybridization of functional molecules to both DNA and RNA, areas that are also discussed in this chapter.
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Affiliation(s)
- Karin E Lundin
- Department of Laboratory Medicine, Clinical Research Center Karolinska Institutet, Karolinska University Hospital, Huddinge 141 86 Stockholm, Sweden
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29
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Abstract
Nonviral gene delivery is limited to a large extent by multiple extracellular and intracellular barriers. One of the major barriers, especially in nondividing cells, is the nuclear envelope. Once in the cytoplasm, plasmids must make their way into the nucleus in order to be expressed. Numerous studies have demonstrated that transfections work best in dividing populations of cells in which the nuclear envelope disassembles during mitosis, thus largely eliminating the barrier. However, since many of the cells that are targets for gene therapy do not actively undergo cell division during the gene transfer process, the mechanisms of nuclear transport of plasmids in nondividing cells are of critical importance. In this review, we summarize recent studies designed to elucidate the mechanisms of plasmid nuclear import in nondividing cells and discuss approaches to either exploit or circumvent these processes to increase the efficiency of gene transfer and therapy.
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Affiliation(s)
- D A Dean
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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30
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Lundin KE, Hasan M, Moreno PM, Törnquist E, Oprea I, Svahn MG, Simonson EO, Smith CIE. Increased stability and specificity through combined hybridization of peptide nucleic acid (PNA) and locked nucleic acid (LNA) to supercoiled plasmids for PNA-anchored "Bioplex" formation. ACTA ACUST UNITED AC 2005; 22:185-92. [PMID: 16144773 DOI: 10.1016/j.bioeng.2005.07.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Low cellular uptake and poor nuclear transfer hamper the use of non-viral vectors in gene therapy. Addition of functional entities to plasmids using the Bioplex technology has the potential to improve the efficiency of transfer considerably. We have investigated the possibility of stabilizing sequence-specific binding of peptide nucleic acid (PNA) anchored functional peptides to plasmid DNA by hybridizing PNA and locked nucleic acid (LNA) oligomers as "openers" to partially overlapping sites on the opposite DNA strand. The PNA "opener" stabilized the binding of "linear" PNA anchors to mixed-base supercoiled DNA in saline. For higher stability under physiological conditions, bisPNA anchors were used. To reduce nonspecific interactions when hybridizing highly cationic constructs and to accommodate the need for increased amounts of bisPNA when the molecules are uncharged, or negatively charged, we used both PNA and LNA oligomers as "openers" to increase binding kinetics. To our knowledge, this is the first time that LNA has been used together with PNA to facilitate strand invasion. This procedure allows hybridization at reduced PNA-to-plasmid ratios, allowing greater than 80% hybridization even at ratios as low as 2:1. Using significantly lower amounts of PNA-peptides combined with shorter incubation times reduces unspecific binding and facilitates purification.
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Affiliation(s)
- Karin E Lundin
- Clinical Research Center, Department of Laboratory Medicine, Karolinska Institutet, Novum PL 5, Karolinska University Hospital, Huddinge, SE-141 86 Stockholm, Sweden.
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31
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Lundin KE, Ge R, Svahn MG, Törnquist E, Leijon M, Brandén LJ, Smith CIE. Cooperative strand invasion of supercoiled plasmid DNA by mixed linear PNA and PNA-peptide chimeras. ACTA ACUST UNITED AC 2005; 21:51-9. [PMID: 15113558 DOI: 10.1016/j.bioeng.2003.10.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2003] [Revised: 09/12/2003] [Accepted: 10/10/2003] [Indexed: 11/28/2022]
Abstract
Peptide nucleic acid (PNA) is a DNA analog with broad biotechnical applications, and possibly also treatment applications. Its suggested uses include that of a specific anchor sequence for biologically active peptides to plasmids in a sequence-specific manner. Such complexes, referred to as Bioplex, have already been used to enhance non-viral gene transfer in vitro. To investigate how hybridization of PNAs to supercoiled plasmids would be affected by the binding of multiple PNA-peptides to the same strand of DNA, we have developed a method of quantifying the specific binding of PNA using a PNA labeled with a derivative of the fluorophore thiazole orange (TO). Cooperative effects were found at a distance of up to three bases. With a peptide present at the end of one of the PNAs, steric hindrance occurred, reducing the increase in binding rate when the distance between the two sites was less than two bases. In addition, we found increased binding kinetics when two PNAs binding to overlapping sites on opposite DNA strands were used, without the use of chemically modified bases in the PNAs.
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Affiliation(s)
- Karin E Lundin
- Clinical Research Center, Karolinska Institutet, Novum Pl. 5, Huddinge University Hospital, SE-141 86 Stockholm, Sweden.
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Kastrup L, Oberleithner H, Ludwig Y, Schafer C, Shahin V. Nuclear envelope barrier leak induced by dexamethasone. J Cell Physiol 2005; 206:428-34. [PMID: 16110478 DOI: 10.1002/jcp.20479] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Nuclear pore complexes (NPCs) are multiprotein channels that span the nuclear envelope. They strongly limit the efficiency of gene transfection by restriction of nuclear delivery of exogenously applied therapeutic macromolecules. NPC dilation could significantly increase this efficiency. Recently, it was shown in oocytes of Xenopus laevis that NPCs dilate from about 82 to 110 nm within min after injection of the glucocorticoid analog dexamethasone (dex). In the present paper we analyzed by means of atomic force microscopy the structural details of NPC dilation and correlated them with functional changes in nuclear envelope permeability. 5-11 min after Dex injection NPC dilation was found at its maximum (approximately 140 nm). In addition, a yet unknown configuration, so-called giant pore, up to 300 nm in diameter, was visualized. Giant pore formation was paralleled by an increase in nuclear envelope permeability tested by electrophysiology and confocal fluorescence microscopy. Even large macromolecules lacking any nuclear localization signal (77 kDa FITC-dextran, molecule diameter up to 36 nm) could gain access to the nucleus. We conclude that dex transiently opens unspecific pathways for large macromolecules. Dex treatment could be potentially useful for improving the efficiency of nuclear gene transfection.
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Affiliation(s)
- Lilian Kastrup
- Institute of Physiology II, University of Muenster, Muenster, Germany
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33
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Abstract
Peptide nucleic acids (PNAs) are synthetic oligonucleotides with chemically modified backbones. PNAs can bind to both DNA and RNA targets in a sequence-specific manner to form PNA/DNA and PNA/RNA duplex structures. When bound to double-stranded DNA (dsDNA) targets, the PNA molecule replaces one DNA strand in the duplex by strand invasion to form a PNA/DNA/PNA [or (PNA)2/DNA] triplex structure and the displaced DNA strand exists as a single-stranded D-loop. PNA has been used in many studies as research tools for gene regulation and gene targeting. The D-loops generated from the PNA binding have also been demonstrated for its potential in initiating transcription and inducing gene expression. PNA provides a powerful tool to study the mechanism of transcription and an innovative strategy to regulate target gene expression. An understanding of the PNA-mediated gene regulation will have important clinical implications in treatment of many human diseases including genetic, cancerous, and age-related diseases.
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Affiliation(s)
- Gan Wang
- Institute of Environmental Health Sciences, Wayne State University, 2727 Second Avenue, Detroit, MI 48201, USA.
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34
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Abstract
Peptide nucleic acids (PNA) are deoxyribonucleic acid (DNA) mimics with a pseudopeptide backbone. PNA is an extremely good structural mimic of DNA (or of ribonucleic acid [RNA]), and PNA oligomers are able to form very stable duplex structures with Watson-Crick complementary DNA and RNA (or PNA) oligomers, and they can also bind to targets in duplex DNA by helix invasion. Therefore, these molecules are of interest in many areas of chemistry, biology, and medicine, including drug discovery, genetic diagnostics, molecular recognition, and the origin of life. Recent progress in studies of PNA properties and applications is reviewed.
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Affiliation(s)
- Peter E Nielsen
- Center for Biomolecular Recognition, IMBG, The Panum Institute, University of Copenhagen, Blegdamsvej 3C, Copenhagen DK-2200N, Denmark.
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35
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Marin VL, Roy S, Armitage BA. Recent advances in the development of peptide nucleic acid as a gene-targeted drug. Expert Opin Biol Ther 2004; 4:337-48. [PMID: 15006728 DOI: 10.1517/14712598.4.3.337] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Peptide nucleic acid (PNA) is a non-ionic mimic of DNA that binds to complementary DNA and RNA sequences with high affinity and selectivity. Targeting of single-stranded RNA leads to antisense effects, whereas PNAs directed toward double-stranded DNA exhibit antigene properties. Recent advances in cell uptake and in antisense and antigene effects in biological systems are summarised in this review. In addition to traditional targets, namely genomic DNA and messenger RNA, applications for PNA as a bacteriocidal antibiotic, for regulating splice site selection and as a telomerase inhibitor are described.
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Affiliation(s)
- Violeta L Marin
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213-3890, USA
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