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Zarrabian M, Sherif SM. Silence is not always golden: A closer look at potential environmental and ecotoxicological impacts of large-scale dsRNA application. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175311. [PMID: 39122031 DOI: 10.1016/j.scitotenv.2024.175311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 08/02/2024] [Accepted: 08/04/2024] [Indexed: 08/12/2024]
Abstract
RNA interference (RNAi) technology has emerged as a pivotal strategy in sustainable pest management, offering a targeted approach that significantly mitigates the environmental and health risks associated with traditional insecticides. Originally implemented through genetically modified organisms (GMOs) to produce specific RNAi constructs, the technology has evolved in response to public and regulatory concerns over GMOs. This evolution has spurred the development of non-transgenic RNAi applications such as spray-induced gene silencing (SIGS), which employs double-stranded RNA (dsRNA) to silence pest genes directly without altering the plant's genetic makeup. Despite its advantages in specificity and reduced ecological footprint, SIGS faces significant obstacles, particularly the instability of dsRNA in field conditions, which limits its practical efficacy. To overcome these limitations, innovative delivery mechanisms have been developed. These include nanotechnology-based systems, minicells, and nanovesicles, which are designed to protect dsRNA from degradation and enhance its delivery to target organisms. While these advancements have improved the stability and application efficiency of dsRNA, comprehensive assessments of their environmental safety and the potential for increased exposure risks to non-target organisms remain incomplete. This comprehensive review aims to elucidate the environmental fate of dsRNA and evaluate the potential risks associated with its widespread application on non-target organisms, encompassing soil microorganisms, beneficial insects, host plants, and mammals. The objective is to establish a more refined framework for RNAi risk assessment within environmental and ecotoxicological contexts, thereby fostering the development of safer, non-transgenic RNAi-based pest control strategies.
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Affiliation(s)
- Mohammad Zarrabian
- Virginia Tech, School of Plant and Environmental Sciences, Alson H. Smith Jr. Agricultural Research, and Extension Center, Winchester, VA 22602, United States
| | - Sherif M Sherif
- Virginia Tech, School of Plant and Environmental Sciences, Alson H. Smith Jr. Agricultural Research, and Extension Center, Winchester, VA 22602, United States.
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2
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Karamali F, Behtaj S, Babaei-Abraki S, Hadady H, Atefi A, Savoj S, Soroushzadeh S, Najafian S, Nasr Esfahani MH, Klassen H. Potential therapeutic strategies for photoreceptor degeneration: the path to restore vision. J Transl Med 2022; 20:572. [PMID: 36476500 PMCID: PMC9727916 DOI: 10.1186/s12967-022-03738-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 10/29/2022] [Indexed: 12/12/2022] Open
Abstract
Photoreceptors (PRs), as the most abundant and light-sensing cells of the neuroretina, are responsible for converting light into electrical signals that can be interpreted by the brain. PR degeneration, including morphological and functional impairment of these cells, causes significant diminution of the retina's ability to detect light, with consequent loss of vision. Recent findings in ocular regenerative medicine have opened promising avenues to apply neuroprotective therapy, gene therapy, cell replacement therapy, and visual prostheses to the challenge of restoring vision. However, successful visual restoration in the clinical setting requires application of these therapeutic approaches at the appropriate stage of the retinal degeneration. In this review, firstly, we discuss the mechanisms of PR degeneration by focusing on the molecular mechanisms underlying cell death. Subsequently, innovations, recent developments, and promising treatments based on the stage of disorder progression are further explored. Then, the challenges to be addressed before implementation of these therapies in clinical practice are considered. Finally, potential solutions to overcome the current limitations of this growing research area are suggested. Overall, the majority of current treatment modalities are still at an early stage of development and require extensive additional studies, both pre-clinical and clinical, before full restoration of visual function in PR degeneration diseases can be realized.
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Affiliation(s)
- Fereshteh Karamali
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Sanaz Behtaj
- grid.1022.10000 0004 0437 5432Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Queensland, Australia ,grid.1022.10000 0004 0437 5432Menzies Health Institute Queensland, Griffith University, Southport, QLD 4222 Australia
| | - Shahnaz Babaei-Abraki
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Hanieh Hadady
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Atefeh Atefi
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Soraya Savoj
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Sareh Soroushzadeh
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Samaneh Najafian
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Mohammad Hossein Nasr Esfahani
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Henry Klassen
- grid.266093.80000 0001 0668 7243Gavin Herbert Eye Institute, Irvine, CA USA
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Darlington M, Reinders JD, Sethi A, Lu AL, Ramaseshadri P, Fischer JR, Boeckman CJ, Petrick JS, Roper JM, Narva KE, Vélez AM. RNAi for Western Corn Rootworm Management: Lessons Learned, Challenges, and Future Directions. INSECTS 2022; 13:57. [PMID: 35055900 PMCID: PMC8779393 DOI: 10.3390/insects13010057] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 12/17/2021] [Accepted: 12/28/2021] [Indexed: 02/06/2023]
Abstract
The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is considered one of the most economically important pests of maize (Zea mays L.) in the United States (U.S.) Corn Belt with costs of management and yield losses exceeding USD ~1-2 billion annually. WCR management has proven challenging given the ability of this insect to evolve resistance to multiple management strategies including synthetic insecticides, cultural practices, and plant-incorporated protectants, generating a constant need to develop new management tools. One of the most recent developments is maize expressing double-stranded hairpin RNA structures targeting housekeeping genes, which triggers an RNA interference (RNAi) response and eventually leads to insect death. Following the first description of in planta RNAi in 2007, traits targeting multiple genes have been explored. In June 2017, the U.S. Environmental Protection Agency approved the first in planta RNAi product against insects for commercial use. This product expresses a dsRNA targeting the WCR snf7 gene in combination with Bt proteins (Cry3Bb1 and Cry34Ab1/Cry35Ab1) to improve trait durability and will be introduced for commercial use in 2022.
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Affiliation(s)
- Molly Darlington
- Department of Entomology, University of Nebraska, Lincoln, NE 68583, USA; (M.D.); (J.D.R.)
| | - Jordan D. Reinders
- Department of Entomology, University of Nebraska, Lincoln, NE 68583, USA; (M.D.); (J.D.R.)
| | - Amit Sethi
- Corteva Agriscience, Johnston, IA 50131, USA; (A.S.); (A.L.L.); (C.J.B.); (J.M.R.)
| | - Albert L. Lu
- Corteva Agriscience, Johnston, IA 50131, USA; (A.S.); (A.L.L.); (C.J.B.); (J.M.R.)
| | | | - Joshua R. Fischer
- Bayer Crop Science, Chesterfield, MO 63017, USA; (P.R.); (J.R.F.); (J.S.P.)
| | - Chad J. Boeckman
- Corteva Agriscience, Johnston, IA 50131, USA; (A.S.); (A.L.L.); (C.J.B.); (J.M.R.)
| | - Jay S. Petrick
- Bayer Crop Science, Chesterfield, MO 63017, USA; (P.R.); (J.R.F.); (J.S.P.)
| | - Jason M. Roper
- Corteva Agriscience, Johnston, IA 50131, USA; (A.S.); (A.L.L.); (C.J.B.); (J.M.R.)
| | | | - Ana M. Vélez
- Department of Entomology, University of Nebraska, Lincoln, NE 68583, USA; (M.D.); (J.D.R.)
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Yasmin T, Adiba M, Saba AA, Nabi AHMN. In Silico Design of siRNAs for Silencing CLEC5A Receptor as a Potential Therapeutic Approach Against Dengue and Japanese Encephalitis Virus Infection in Human. Bioinform Biol Insights 2022; 16:11779322221142122. [DOI: 10.1177/11779322221142122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 11/09/2022] [Indexed: 12/14/2022] Open
Abstract
Dengue and Japanese encephalitis virus (JEV) are mosquito-borne RNA viruses that can cause severe illness leading to death in the tropics and subtropics. Both of these viruses interact directly with the C-type lectin domain family 5, member A receptor (CLEC5A) on human macrophages which stimulates the release of proinflammatory cytokines. Since blockade of this interaction has been shown to suppress the secretion of cytokines, CLEC5A is considered a potential target for the development of new treatments to reduce virus-induced brain damage. Developing a vaccine against dengue is challenging because this virus can cause disease through 4 different serotypes. Therefore, the vaccine must immunize against all 4 serotypes to be effective, while unvaccinated people still contract JEV and suffer from its complications. Small interfering RNAs (siRNAs) play an important role in regulating gene expression by causing the degradation of target mRNAs. In this study, we attempted to rationally design potential siRNA molecules using various software, targeting the CLEC5A gene. In total, 3 siRNAs were found to be potential candidates for CLEC5A silencing. They showed good target accessibility, optimum guanine-cytosine (GC) content, the least chance of off-target effects, positive energy of folding, and strong interaction with Argonaute2 protein as denoted by a negative docking energy score. In addition, molecular dynamics simulation of the siRNA-Ago2-docked complexes showed the stability of the complexes over 1.5 nanoseconds. These predicted siRNAs might effectively downregulate the expression of the CLEC5A receptor and thus prove vital in the treatment of dengue and JEV infections.
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Affiliation(s)
- Tahirah Yasmin
- Laboratory of Population Genetics, Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka, Bangladesh
| | - Maisha Adiba
- Laboratory of Population Genetics, Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka, Bangladesh
| | - Abdullah Al Saba
- Laboratory of Population Genetics, Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka, Bangladesh
| | - AHM Nurun Nabi
- Laboratory of Population Genetics, Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka, Bangladesh
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Baxi K, Sawarkar S, Momin M, Patel V, Fernandes T. Vaginal siRNA delivery: overview on novel delivery approaches. Drug Deliv Transl Res 2020; 10:962-974. [DOI: 10.1007/s13346-020-00741-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Rodrigues TB, Petrick JS. Safety Considerations for Humans and Other Vertebrates Regarding Agricultural Uses of Externally Applied RNA Molecules. FRONTIERS IN PLANT SCIENCE 2020; 11:407. [PMID: 32391029 PMCID: PMC7191066 DOI: 10.3389/fpls.2020.00407] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 03/20/2020] [Indexed: 05/13/2023]
Abstract
The potential of double-stranded RNAs (dsRNAs) for use as topical biopesticides in agriculture was recently discussed during an OECD (Organisation for Economic Co-operation and Development) Conference on RNA interference (RNAi)-based pesticides. Several topics were presented and these covered different aspects of RNAi technology, its application, and its potential effects on target and non-target organisms (including both mammals and non-mammals). This review presents information relating to RNAi mechanisms in vertebrates, the history of safe RNA consumption, the biological barriers that contribute to the safety of its consumption, and effects related to humans and other vertebrates as discussed during the conference. We also review literature related to vertebrates exposed to RNA molecules and further consider human health safety assessments of RNAi-based biopesticides. This includes possible routes of exposure other than the ingestion of potential residual material in food and water (such as dermal and inhalation exposures during application in the field), the implications of different types of formulations and RNA structures, and the possibility of non-specific effects such as the activation of the innate immune system or saturation of the RNAi machinery.
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Affiliation(s)
| | - Jay S. Petrick
- Bayer Crop Science, Chesterfield, MO, United States
- *Correspondence: Jay S. Petrick,
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Raja MAG, Katas H, Amjad MW. Design, mechanism, delivery and therapeutics of canonical and Dicer-substrate siRNA. Asian J Pharm Sci 2019; 14:497-510. [PMID: 32104477 PMCID: PMC7032099 DOI: 10.1016/j.ajps.2018.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 12/07/2018] [Accepted: 12/24/2018] [Indexed: 12/12/2022] Open
Abstract
Upon the discovery of RNA interference (RNAi), canonical small interfering RNA (siRNA) has been recognized to trigger sequence-specific gene silencing. Despite the benefits of siRNAs as potential new drugs, there are obstacles still to be overcome, including off-target effects and immune stimulation. More recently, Dicer substrate siRNA (DsiRNA) has been introduced as an alternative to siRNA. Similarly, it also is proving to be potent and target-specific, while rendering less immune stimulation. DsiRNA is 25–30 nucleotides in length, and is further cleaved and processed by the Dicer enzyme. As with siRNA, it is crucial to design and develop a stable, safe, and efficient system for the delivery of DsiRNA into the cytoplasm of targeted cells. Several polymeric nanoparticle systems have been well established to load DsiRNA for in vitro and in vivo delivery, thereby overcoming a major hurdle in the therapeutic uses of DsiRNA. The present review focuses on a comparison of siRNA and DsiRNA on the basis of their design, mechanism, in vitro and in vivo delivery, and therapeutics.
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Affiliation(s)
- Maria Abdul Ghafoor Raja
- Department of Pharmaceutics, Faculty of Pharmacy, Northern Border University, Rafha 73211, Saudi Arabia
| | - Haliza Katas
- Centre for Drug Delivery Research, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia
| | - Muhammad Wahab Amjad
- Department of Pharmaceutics, Faculty of Pharmacy, Northern Border University, Rafha 73211, Saudi Arabia
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Gatta AK, Hariharapura RC, Udupa N, Reddy MS, Josyula VR. Strategies for improving the specificity of siRNAs for enhanced therapeutic potential. Expert Opin Drug Discov 2018; 13:709-725. [PMID: 29902093 DOI: 10.1080/17460441.2018.1480607] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION RNA interference has become a tool of choice in the development of drugs in various therapeutic areas of Post Transcriptional Gene Silencing (PTGS). The critical element in developing successful RNAi therapeutics lies in designing small interfering RNA (siRNA) using an efficient algorithm satisfying the designing criteria. Further, translation of siRNA from bench-side to bedside needs an efficient delivery system and/or chemical modification. Areas covered: This review emphasizes the importance of dicer, the criteria for efficient siRNA design, the currently available algorithms and strategies to overcome off-target effects, immune stimulatory effects and endosomal trap. Expert opinion: Specificity and stability are the primary concerns for siRNA therapeutics. The design criteria and algorithms should be chosen rationally to have a siRNA sequence that binds to the corresponding mRNA as it happens in the Watson and Crick base pairing. However, it must evade a few more hurdles (Endocytosis, Serum stability etc.) to be functional in the cytosol.
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Affiliation(s)
- Aditya Kiran Gatta
- a Cell and Molecular Biology lab, Department of Pharmaceutical Biotechnology , Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education , Manipal , Karnataka , India
| | - Raghu Chandrashekhar Hariharapura
- a Cell and Molecular Biology lab, Department of Pharmaceutical Biotechnology , Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education , Manipal , Karnataka , India
| | - Nayanabhirama Udupa
- b Research Directorate of Health Sciences , Manipal Academy of Higher Education , Manipal , Karnataka , India
| | - Meka Sreenivasa Reddy
- c Department of Pharmaceutics, Manipal College of Pharmaceutical Sciences , Manipal Academy of Higher Education , Manipal , Karnataka , India
| | - Venkata Rao Josyula
- a Cell and Molecular Biology lab, Department of Pharmaceutical Biotechnology , Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education , Manipal , Karnataka , India
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9
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Recent advances in the design, development, and targeting mechanisms of polymeric micelles for delivery of siRNA in cancer therapy. Prog Polym Sci 2017. [DOI: 10.1016/j.progpolymsci.2016.09.008] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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10
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Petrick JS, Frierdich GE, Carleton SM, Kessenich CR, Silvanovich A, Zhang Y, Koch MS. Corn rootworm-active RNA DvSnf7: Repeat dose oral toxicology assessment in support of human and mammalian safety. Regul Toxicol Pharmacol 2016; 81:57-68. [PMID: 27436086 DOI: 10.1016/j.yrtph.2016.07.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 07/14/2016] [Accepted: 07/15/2016] [Indexed: 02/01/2023]
Abstract
Genetically modified (GM) crops have been developed and commercialized that utilize double stranded RNAs (dsRNA) to suppress a target gene(s), producing virus resistance, nutritional and quality traits. MON 87411 is a GM maize variety that leverages dsRNAs to selectively control corn rootworm through production of a 240 base pair (bp) dsRNA fragment targeting for suppression the western corn rootworm (Diabrotica virgifera virgifera) Snf7 gene (DvSnf7). A bioinformatics assessment found that endogenous corn small RNAs matched ∼450 to 2300 unique RNA transcripts that likely code for proteins in rat, mouse, and human, demonstrating safe dsRNA consumption by mammals. Mice were administered DvSnf7 RNA (968 nucleotides, including the 240 bp DvSnf7 dsRNA) at 1, 10, or 100 mg/kg by oral gavage in a 28-day repeat dose toxicity study. No treatment-related effects were observed in body weights, food consumption, clinical observations, clinical chemistry, hematology, gross pathology, or histopathology endpoints. Therefore, the No Observed Adverse Effect Level (NOAEL) for DvSnf7 RNA was 100 mg/kg, the highest dose tested. These results demonstrate that dsRNA for insect control does not produce adverse health effects in mammals at oral doses millions to billions of times higher than anticipated human exposures and therefore poses negligible risk to mammals.
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Affiliation(s)
- Jay S Petrick
- Monsanto Company, 800 North Lindbergh Boulevard, Creve Coeur, MO 63167, USA.
| | | | | | - Colton R Kessenich
- Monsanto Company, 800 North Lindbergh Boulevard, Creve Coeur, MO 63167, USA
| | - Andre Silvanovich
- Monsanto Company, 800 North Lindbergh Boulevard, Creve Coeur, MO 63167, USA
| | - Yuanji Zhang
- Monsanto Company, 800 North Lindbergh Boulevard, Creve Coeur, MO 63167, USA
| | - Michael S Koch
- Monsanto Company, 800 North Lindbergh Boulevard, Creve Coeur, MO 63167, USA
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Designing idiosyncratic hmPCL -siRNA nanoformulated capsules for silencing and cancer therapy. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2016; 12:579-588. [DOI: 10.1016/j.nano.2015.10.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Revised: 10/13/2015] [Accepted: 10/19/2015] [Indexed: 01/24/2023]
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12
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Petrick JS, Moore WM, Heydens WF, Koch MS, Sherman JH, Lemke SL. A 28-day oral toxicity evaluation of small interfering RNAs and a long double-stranded RNA targeting vacuolar ATPase in mice. Regul Toxicol Pharmacol 2014; 71:8-23. [PMID: 25445299 DOI: 10.1016/j.yrtph.2014.10.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 10/24/2022]
Abstract
New biotechnology-derived crop traits have been developed utilizing the natural process of RNA interference (RNAi). However, plant-produced double stranded RNAs (dsRNAs) are not known to present a hazard to mammals because numerous biological barriers limit uptake and potential for activity. To evaluate this experimentally, dsRNA sequences matching the mouse vATPase gene (an established target for control of corn rootworms) were evaluated in a 28-day toxicity study with mice. Test groups were orally gavaged with escalating doses of either a pool of four 21-mer vATPase small interfering RNAs (siRNAs) or a 218-base pair vATPase dsRNA. There were no treatment-related effects on body weight, food consumption, clinical observations, clinical chemistry, hematology, gross pathology, or histopathology endpoints. The highest dose levels tested were considered to be the no observed adverse effect levels (NOAELs) for the 21-mer siRNAs (48 mg/kg/day) and the 218 bp dsRNA (64 mg/kg/day). As an additional exploratory endpoint, vATPase gene expression, was evaluated in selected gastrointestinal tract and systemic tissues. The results of this assay did not indicate treatment-related suppression of vATPase. The results of this study indicate that orally ingested dsRNAs, even those targeting a gene in the test species, do not produce adverse health effects in mammals.
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Affiliation(s)
- Jay S Petrick
- Monsanto Company, 800 North Lindbergh Boulevard, Creve Coeur, MO 63167, USA.
| | - William M Moore
- Monsanto Company, 800 North Lindbergh Boulevard, Creve Coeur, MO 63167, USA
| | - William F Heydens
- Monsanto Company, 800 North Lindbergh Boulevard, Creve Coeur, MO 63167, USA
| | - Michael S Koch
- Monsanto Company, 800 North Lindbergh Boulevard, Creve Coeur, MO 63167, USA
| | - James H Sherman
- Monsanto Company, 800 North Lindbergh Boulevard, Creve Coeur, MO 63167, USA
| | - Shawna L Lemke
- Monsanto Company, 800 North Lindbergh Boulevard, Creve Coeur, MO 63167, USA
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Won YW, Bull DA, Kim SW. Functional polymers of gene delivery for treatment of myocardial infarct. J Control Release 2014; 195:110-9. [PMID: 25076177 DOI: 10.1016/j.jconrel.2014.07.041] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 07/18/2014] [Accepted: 07/20/2014] [Indexed: 01/18/2023]
Abstract
Ischemic heart disease is rapidly growing as the common cause of death in the world. It is a disease that occurs as a result of coronary artery stenosis and is caused by the lack of oxygen within cardiac muscles due to an imbalance between oxygen supply and demand. The conventional medical therapy is focused on the use of drug eluting stents, coronary-artery bypass graft surgery and anti-thrombosis. Gene therapy provides great opportunities for treatment of cardiovascular disease. In order for gene therapy to be successful, the development of proper gene delivery systems and hypoxia-regulated gene expression vectors is the most important factors. Several non-viral gene transfer methods have been developed to overcome the safety problems of viral transduction. Some of which include plasmids that regulate gene expression that is controlled by environment specific promoters in the transcriptional or the translational level. This review explores polymeric gene carriers that target the myocardium and hypoxia-inducible vectors, which regulate gene expression in response to hypoxia, and their application in animal myocardial infarction models.
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Affiliation(s)
- Young-Wook Won
- Center for Controlled Chemical Delivery (CCCD), Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT, USA; Division of Cardiothoracic Surgery, Department of Surgery, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - David A Bull
- Division of Cardiothoracic Surgery, Department of Surgery, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Sung Wan Kim
- Center for Controlled Chemical Delivery (CCCD), Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT, USA.
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14
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Cell type and transfection reagent-dependent effects on viability, cell content, cell cycle and inflammation of RNAi in human primary mesenchymal cells. Eur J Pharm Sci 2014; 53:35-44. [DOI: 10.1016/j.ejps.2013.12.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 11/09/2013] [Accepted: 12/08/2013] [Indexed: 12/22/2022]
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15
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Restani RB, Conde J, Baptista PV, Cidade MT, Bragança AM, Morgado J, Correia IJ, Aguiar-Ricardo A, Bonifácio VDB. Polyurea dendrimer for efficient cytosolic siRNA delivery. RSC Adv 2014. [DOI: 10.1039/c4ra09603g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
PURE-type dendrimers are a useful gene silencing platform showing efficient cytosolic siRNA delivery with high transfection efficacy.
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Affiliation(s)
- Rita B. Restani
- REQUIMTE
- Departamento de Química
- Faculdade de Ciências e Tecnologia
- Universidade Nova de Lisboa
- Campus de Caparica
| | - João Conde
- CIGMH
- Departamento de Ciências da Vida
- Faculdade de Ciências e Tecnologia
- Universidade Nova de Lisboa
- Campus de Caparica
| | - Pedro V. Baptista
- CIGMH
- Departamento de Ciências da Vida
- Faculdade de Ciências e Tecnologia
- Universidade Nova de Lisboa
- Campus de Caparica
| | - Maria Teresa Cidade
- Departamento de Ciências dos Materiais e Cenimat
- Faculdade de Ciências e Tecnologia
- Universidade Nova de Lisboa
- Campus de Caparica
- 2829-516 Caparica, Portugal
| | - Ana M. Bragança
- Instituto de Telecomunicações
- Instituto Superior Técnico
- 1049-001 Lisboa, Portugal
| | - Jorge Morgado
- Instituto de Telecomunicações
- Instituto Superior Técnico
- 1049-001 Lisboa, Portugal
- Departamento de Bioengenharia
- Instituto Superior Técnico
| | - Ilídio J. Correia
- CICS-UBI Health Sciences Research Center
- University of Beira Interior
- 6200-506 Covilhã, Portugal
| | - Ana Aguiar-Ricardo
- REQUIMTE
- Departamento de Química
- Faculdade de Ciências e Tecnologia
- Universidade Nova de Lisboa
- Campus de Caparica
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Stigliano C, Aryal S, de Tullio MD, Nicchia GP, Pascazio G, Svelto M, Decuzzi P. siRNA-chitosan complexes in poly(lactic-co-glycolic acid) nanoparticles for the silencing of aquaporin-1 in cancer cells. Mol Pharm 2013; 10:3186-94. [PMID: 23789777 DOI: 10.1021/mp400224u] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A large number of studies document the strong expression of aquaporin-1 (AQP1) in tumor microvessels and correlate this aberrant expression with higher metastatic potential and aggressiveness of the malignancy. Although small animal experiments have shown that the modulation of AQP1 expression can halt angiogenesis and induce tumor regression, effective and safe strategies for the tissue specific inhibition of AQP1 are still missing. Here, small interference RNA-chitosan complexes encapsulated in poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) are proposed for the intracellular delivery of siRNA molecules against AQP1. These NPs are coated with poly(vinyl alcohol) (PVA), to improve stability under physiological conditions, and demonstrate a diameter of 160 nm. The partial neutralization of the negatively charged siRNA molecules with the cationic chitosan enhances the loading by 5-fold, as compared to that of the free siRNA molecules, and allows one to modulate the release kinetics in the pH-dependent manner. At pH = 7.4, mimicking the conditions found in the systemic circulation, only the 40% of siRNA is released at 24 h post incubation; whereas at pH = 5.0, recreating the cell endosomal environment, all siRNA molecules are released in about 3 h. These NPs show no cytotoxicity on HeLa cells up to 72 h of incubation. In the same cells, transfected to overexpress AQP1, a silencing efficiency of 70% is achieved at 24 h post treatment with siRNA-loaded NPs. Confocal microscopy analysis of NP uptake demonstrates that siRNA molecules accumulate perinuclearly and in the nucleus. Given the stability, preferential release behavior, and well-known biocompatibility properties of PLGA nanostructures, these siRNA-loaded NPs hold potential for the efficient and safe in vivo silencing of AQPs via systemic administration.
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Affiliation(s)
- Cinzia Stigliano
- Department of Translational Imaging and Department of Nanomedicine, The Methodist Hospital Research Institute, Houston, Texas 77030, United States
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Petrick JS, Brower-Toland B, Jackson AL, Kier LD. Safety assessment of food and feed from biotechnology-derived crops employing RNA-mediated gene regulation to achieve desired traits: a scientific review. Regul Toxicol Pharmacol 2013; 66:167-76. [PMID: 23557984 DOI: 10.1016/j.yrtph.2013.03.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 03/19/2013] [Accepted: 03/22/2013] [Indexed: 01/09/2023]
Abstract
Gene expression can be modulated in plants to produce desired traits through agricultural biotechnology. Currently, biotechnology-derived crops are compared to their conventional counterparts, with safety assessments conducted on the genetic modification and the intended and unintended differences. This review proposes that this comparative safety assessment paradigm is appropriate for plants modified to express mediators of RNA-mediated gene regulation, including RNA interference (RNAi), a gene suppression mechanism that naturally occurs in plants and animals. The molecular mediators of RNAi, including long double-stranded RNAs (dsRNA), small interfering RNAs (siRNA), and microRNAs (miRNA), occur naturally in foods; therefore, there is an extensive history of safe consumption. Systemic exposure following consumption of plants containing dsRNAs that mediate RNAi is limited in higher organisms by extensive degradation of ingested nucleic acids and by biological barriers to uptake and efficacy of exogenous nucleic acids. A number of mammalian RNAi studies support the concept that a large margin of safety will exist for any small fraction of RNAs that might be absorbed following consumption of foods from biotechnology-derived plants that employ RNA-mediated gene regulation. Food and feed derived from these crops utilizing RNA-based mechanisms is therefore expected to be as safe as food and feed derived through conventional plant breeding.
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Affiliation(s)
- Jay S Petrick
- Monsanto Company, 800 N. Lindbergh Blvd, St. Louis, MO 63167, USA.
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Kadengodlu PA, Aigaki T, Abe H, Ito Y. Cationic cholesterol-modified gelatin as an in vitro siRNA delivery vehicle. MOLECULAR BIOSYSTEMS 2013; 9:965-8. [DOI: 10.1039/c2mb25424g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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19
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Abstract
siRNA therapeutics has developed rapidly and already there are clinical trials ongoing or planned; however, the delivery of siRNA into cells, tissues or organs remains to be a major obstacle. Lipid-based vectors hold the most promising position among non-viral vectors, as they have a similar structure to cell or organelle membranes. But when used in the form of liposomes, these vectors have shown some problems. Therefore, either the nature of lipids themselves or forms used should be improved. As a novel class of lipid like materials, lipidoids have the advantages of easy synthesis and the ability for delivering siRNA to obtain excellent silencing activity. However, the toxicities of lipidoids have not been thoroughly studied. pH responsive lipids have also gained great attention recently, though some of the amine-based lipids are not novel in terms of chemical structures. More complex self-assembly structures, such as LPD (LPH) and LCP, may provide a good solution to siRNA delivery. They have demonstrated controlled particle morphology and size and siRNA delivery activity for both in vitro and in vivo.
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Affiliation(s)
- Shubiao Zhang
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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20
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Glebova KV, Marakhonov AV, Baranova AV, Skoblov MY. Nonviral delivery systems for small interfering RNAs. Mol Biol 2012. [DOI: 10.1134/s0026893312020070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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21
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Ryou SM, Park M, Kim JM, Jeon CO, Yun CH, Han SH, Kim SW, Lee Y, Kim S, Han MS, Bae J, Lee K. Inhibition of xenograft tumor growth in mice by gold nanoparticle-assisted delivery of short hairpin RNAs against Mcl-1L. J Biotechnol 2011; 156:89-94. [DOI: 10.1016/j.jbiotec.2011.07.037] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 07/26/2011] [Indexed: 11/26/2022]
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22
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Cho HY, Srinivasan A, Hong J, Hsu E, Liu S, Shrivats A, Kwak D, Bohaty AK, Paik HJ, Hollinger JO, Matyjaszewski K. Synthesis of Biocompatible PEG-Based Star Polymers with Cationic and Degradable Core for siRNA Delivery. Biomacromolecules 2011; 12:3478-86. [DOI: 10.1021/bm2006455] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Hong Y. Cho
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Abiraman Srinivasan
- Bone Tissue Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Joanna Hong
- Bone Tissue Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Eric Hsu
- Bone Tissue Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Shiguang Liu
- Bone Tissue Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Arun Shrivats
- Bone Tissue Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Dan Kwak
- Bone Tissue Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Andrew K. Bohaty
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Hyun-jong Paik
- Department of Polymer Science and Engineering, Pusan National University, Busan, South Korea
| | - Jeffrey O. Hollinger
- Bone Tissue Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Krzysztof Matyjaszewski
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
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23
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SiRNA delivery with functionalized carbon nanotubes. Int J Pharm 2011; 416:419-25. [DOI: 10.1016/j.ijpharm.2011.02.009] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 02/05/2011] [Accepted: 02/07/2011] [Indexed: 12/16/2022]
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24
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Varkouhi AK, Lammers T, Schiffelers RM, van Steenbergen MJ, Hennink WE, Storm G. Gene silencing activity of siRNA polyplexes based on biodegradable polymers. Eur J Pharm Biopharm 2011; 77:450-7. [DOI: 10.1016/j.ejpb.2010.11.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 11/20/2010] [Accepted: 11/23/2010] [Indexed: 10/18/2022]
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Abstract
RNA interference (RNAi) has been regarded as a revolutionary tool for manipulating target biological processes as well as an emerging and promising therapeutic strategy. In contrast to the tangible and obvious effectiveness of RNAi in vitro, silencing target gene expression in vivo using small interfering RNA (siRNA) has been a very challenging task due to multiscale barriers, including rapid excretion, low stability in blood serum, nonspecific accumulation in tissues, poor cellular uptake and inefficient intracellular release. This minireview introduces major challenges in achieving efficient siRNA delivery in vivo and discusses recent advances in overcoming them using chemically modified siRNA, viral siRNA vectors and nonviral siRNA carriers. Enhanced specificity and efficiency of RNAi in vivo via selective accumulations in desired tissues, specific binding to target cells and facilitated intracellular trafficking are also commonly attempted utilizing targeting moieties, cell-penetrating peptides, fusogenic peptides and stimuli-responsive polymers. Overall, the crucial roles of the interdisciplinary approaches to optimizing RNAi in vivo, by efficiently and specifically delivering siRNA to target tissues and cells, are highlighted.
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Affiliation(s)
- Min Suk Shim
- Department of Chemical Engineering and Materials Science, University of California, Irvine, CA 92697, USA
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26
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Merkel OM, Mintzer MA, Librizzi D, Samsonova O, Dicke T, Sproat B, Garn H, Barth PJ, Simanek EE, Kissel T. Triazine dendrimers as nonviral vectors for in vitro and in vivo RNAi: the effects of peripheral groups and core structure on biological activity. Mol Pharm 2010; 7:969-83. [PMID: 20524664 DOI: 10.1021/mp100101s] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A family of triazine dendrimers, differing in their core flexibility, generation number, and surface functionality, was prepared and evaluated for its ability to accomplish RNAi. The dendriplexes were analyzed with respect to their physicochemical and biological properties, including condensation of siRNA, complex size, surface charge, cellular uptake and subcellular distribution, their potential for reporter gene knockdown in HeLa/Luc cells, and ultimately their stability, biodistribution, pharmacokinetics and intracellular uptake in mice after intravenous (iv) administration. The structure of the backbone was found to significantly influence siRNA transfection efficiency, with rigid, second generation dendrimers displaying higher gene knockdown than the flexible analogues while maintaining less off-target effects than Lipofectamine. Additionally, among the rigid, second generation dendrimers, those with either arginine-like exteriors or peripheries containing hydrophobic functionalities mediated the most effective gene knockdown, thus showing that dendrimer surface groups also affect transfection efficiency. Moreover, these two most effective dendriplexes were stable in circulation upon intravenous administration and showed passive targeting to the lung. Both dendriplex formulations were taken up into the alveolar epithelium, making them promising candidates for RNAi in the lung. The ability to correlate the effects of triazine dendrimer core scaffolds, generation number, and surface functionality with siRNA transfection efficiency yields valuable information for further modifying this nonviral delivery system and stresses the importance of only loosely correlating effective gene delivery vectors with siRNA transfection agents.
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Affiliation(s)
- Olivia M Merkel
- Department of Pharmaceutics and Biopharmacy, Philipps-Universitat, Marburg, Germany
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27
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Varkouhi AK, Verheul RJ, Schiffelers RM, Lammers T, Storm G, Hennink WE. Gene silencing activity of siRNA polyplexes based on thiolated N,N,N-trimethylated chitosan. Bioconjug Chem 2010; 21:2339-46. [PMID: 21049986 DOI: 10.1021/bc1003789] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
N,N,N-Trimethylated chitosan (TMC) is a biodegradable polymer emerging as a promising nonviral vector for nucleic acid and protein delivery. In the present study, we investigated whether the introduction of thiol groups in TMC enhances the extracellular stability of the complexes based on this polymer and promotes the intracellular release of siRNA. The gene silencing activity and the cellular cytotoxicity of polyplexes based on thiolated TMC were compared with those based on the nonthiolated counterpart and the regularly used lipidic transfection agent Lipofectamine. Incubation of H1299 human lung cancer cells expressing firefly luciferase with siRNA/thiolated TMC polyplexes resulted in 60-80% gene silencing activity, whereas complexes based on nonthiolated TMC showed less silencing (40%). The silencing activity of the complexes based on Lipofectamine 2000 was about 60-70%. Importantly, the TMC-SH polyplexes retained their silencing activity in the presence of hyaluronic acid, while nonthiolated TMC polyplexes hardly showed any silencing activity, demonstrating their stability against competing anionic macromolecules. Under the experimental conditions tested, the cytotoxicity of the thiolated and nonthiolated siRNA complexes was lower than those based on Lipofectamine. Given the good extracellular stability and good silencing activity, it is concluded that polyplexes based on TMC-SH are attractive systems for further in vivo evaluations.
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Affiliation(s)
- Amir K Varkouhi
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht, The Netherlands
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28
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Akhtar S. Cationic nanosystems for the delivery of small interfering ribonucleic acid therapeutics: a focus on toxicogenomics. Expert Opin Drug Metab Toxicol 2010; 6:1347-62. [PMID: 20929276 DOI: 10.1517/17425255.2010.518611] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
IMPORTANCE OF THE FIELD siRNAs may serve as novel nanomedicines for sequence-specific gene silencing in the clinic. However, delivering siRNA to targeted tissue or cells remains a challenge. An appropriate delivery nanosystem such as cationic polymers or liposomes is required for effective gene silencing with siRNA in vivo but the available drug delivery vectors are not all biologically inert. AREAS COVERED IN THIS REVIEW A combination of highly focused and comprehensive literature searches to identify any relevant reports using Medline (from 1950 to 7 April 2010) through the OVID system. WHAT THE READER WILL GAIN Using cationic delivery nanosystems as examples, this review article highlights the importance of undertaking toxicogenomics studies - the application of transcription profiling to toxicology - to acquire gene expression signatures of siRNA delivery systems so as to determine and/or predict their impact on gene silencing activity and specificity. Such nanotoxicological information will be important for the optimal selection of siRNA-delivery system combinations in the many proposed clinical applications of RNA interference. TAKE HOME MESSAGE Cationic delivery nanosystems can elicit multiple gene expression changes in cells that may contribute to the 'off-target' effects of siRNAs and/or modulate their pharmacological activity. Thus, selection of delivery systems for siRNA applications should be based on both their delivery enhancing capability and toxicogenomics.
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Affiliation(s)
- Saghir Akhtar
- Kuwait University, Health Sciences Centre, Department of Pharmacology and Toxicology, Faculty of Medicine, PO Box 24923, Safat 13110, Kuwait.
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29
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Jackson AL, Linsley PS. Recognizing and avoiding siRNA off-target effects for target identification and therapeutic application. Nat Rev Drug Discov 2010; 9:57-67. [PMID: 20043028 DOI: 10.1038/nrd3010] [Citation(s) in RCA: 728] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Small interfering RNAs (siRNAs) are widely used to study gene function owing to the ease with which they silence target genes, and there is considerable interest in their potential for therapeutic applications. In a remarkably short time since their discovery, siRNAs have entered human clinical trials in various disease areas. However, rapid acceptance of the use of siRNAs has been accompanied by recognition of several hurdles for the technology, including a lack of specificity. Off-target activity can complicate the interpretation of phenotypic effects in gene-silencing experiments and can potentially lead to unwanted toxicities. Here, we describe the types of off-target effects of siRNAs and methods to mitigate them, to help enable effective application of this exciting technology.
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Affiliation(s)
- Aimee L Jackson
- Regulus Therapeutics, Inc., 1896 Rutherford Road, Carlsbad, CA 92008, USA.
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30
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Dutta T, Burgess M, McMillan NAJ, Parekh HS. Dendrosome-based delivery of siRNA against E6 and E7 oncogenes in cervical cancer. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2010; 6:463-70. [PMID: 20044033 DOI: 10.1016/j.nano.2009.12.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Revised: 10/08/2009] [Accepted: 12/02/2009] [Indexed: 10/20/2022]
Abstract
UNLABELLED Although small interfering RNA (siRNA) treatment holds great promise for the treatment of cancers, the field has been held back by the availability of suitable delivery vehicles. For cervical cancer the E6 and E7 oncogenes are ideal siRNA targets for treatment. The purpose of the present study was to explore the potential of dendrosomes for the delivery of siRNA targeting E6 and E7 proteins of cervical cancer cells in vitro. Optimization of dendrimer generation and nitrogen-to-phosphate (N/P) ratio was carried out using dendrimer-fluorescein isothiocyanate oligo complexes. The optimized N/P ratios were used in formulating complexes between dendrimers and siRNA targeting green fluorescence protein (siGFP). Although formulation 4D100 (dendrimer-siRNA complex) displayed the highest GFP knockdown, it was also found to be highly toxic to cells. In the final formulation 4D100 was encapsulated into dendrosomes so as to mask these toxic effects. The optimized dendrosomal formulation (DF), DF3 was found to possess a siGFP-entrapment efficiency of 49.76% +/- 1.62%, vesicle size of 154 +/- 1.73 nm, and zeta potential of +3.21 +/- 0.07 mV. The GFP knockdown efficiency of DF3 (dendrosome) was found to be almost identical to that of 4D100, but the former was completely nontoxic to the cells. DF3 containing siRNA against E6 and E7 was found to knock down the target genes considerably, as compared with the other formulations tested. Our results imply that dendrosomes hold potential for the delivery of siRNA and that a suitable targeting strategy could be useful for applications in vivo. FROM THE CLINICAL EDITOR siRNA treatment holds great promise for the treatment of cancers, but overall, the availability of suitable delivery vehicles remains a major issue. The purpose of this study was to explore the potential of dendrosomes for the delivery of siRNA targeting specific proteins in cervical cancer cells in vitro. The results suggest that dendrosomes hold potential for the delivery of siRNA and a suitable targeting strategy could be useful for applications in vivo.
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Affiliation(s)
- Tathagata Dutta
- School of Pharmacy, University of Queensland, Brisbane, Australia
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31
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Abstract
With the recent discovery of small interfering RNA (siRNA), to silence the expression of genes in vitro and in vivo, there has been a need to deliver these molecules to the cell nucleus. Forming a lipid/nucleic acid complex has become a solution and is explored here. Certain methods and ideas are used, such as: the positive/negative electrostatic interaction with a cationic lipid and an anionic RNA molecule, the size of the lipid vesicle aiding the uptake target tissues, targeted lipoplexes which can increase efficiency, and the protection of the siRNA molecule from the natural defenses of the immune system. Many lipid formulations exist and can be experimented with to achieve varying results depending on the application.
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Affiliation(s)
- Jeffrey Hughes
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA
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32
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Abstract
RNA interference (RNAi) as a mechanism to selectively degrade mRNA (mRNA) expression has emerged as a potential novel approach for drug target validation and the study of functional genomics. Small interfering RNAs (siRNA) therapeutics has developed rapidly and already there are clinical trials ongoing or planned. Although other challenges remain, delivery strategies for siRNA become the main hurdle that must be resolved prior to the full-scale clinical development of siRNA therapeutics. This review provides an overview of the current delivery strategies for synthetic siRNA, focusing on the targeted, self-assembled nanoparticles which show potential to become a useful and efficient tool in cancer therapy.
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Affiliation(s)
- Kun Gao
- University of North Carolina, Chapel Hill, North Carolina 27599, USA
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33
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Flatekval GF, Sioud M. Modulation of dendritic cell maturation and function with mono- and bifunctional small interfering RNAs targeting indoleamine 2,3-dioxygenase. Immunology 2009; 128:e837-48. [PMID: 19740345 DOI: 10.1111/j.1365-2567.2009.03093.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Antigen-presenting cells expressing indoleamine 2,3-dioxygenase (IDO) play a critical role in maintaining peripheral tolerance. Strategies to inhibit IDO gene expression and enhance antigen-presenting cell function might improve anti-tumour immunity. Here we have designed highly effective anti-IDO small interfering (si) RNAs that function at low concentrations. When delivered to human primary immune cells such as monocytes and dendritic cells (DCs), they totally inhibited IDO gene expression without impairing DC maturation and function. Depending on the design and chemical modifications, we show that it is possible to design either monofunctional siRNAs devoid of immunostimulation or bifunctional siRNAs with gene silencing and immunostimulatory activities. The latter are able to knockdown IDO expression and induce cytokine production through either endosomal Toll-like receptor 7/8 or cytoplasmic retinoid acid-inducible gene 1 helicase. Inhibition of IDO expression with both classes of siRNAs inhibited DC immunosuppressive function on T-cell proliferation. Immature monocyte-derived DCs that had been transfected with siRNA-bearing 5'-triphosphate activated T cells, indicating that, even in the absence of external stimuli such as tumour necrosis factor-alpha, those DCs were sufficiently mature to initiate T-cell activation. Collectively, our data highlight the potential therapeutic applications of this new generation of siRNAs in immunotherapy.
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Affiliation(s)
- Gro F Flatekval
- Department of Immunology, Institute for Cancer Research, Rikshospitalet-Radiumhospitalet Medical Centre, Montebello, Oslo, Norway
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34
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Efficient siRNA delivery with non-viral polymeric vehicles. Pharm Res 2008; 26:657-66. [PMID: 19015957 DOI: 10.1007/s11095-008-9774-1] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2008] [Accepted: 10/28/2008] [Indexed: 10/21/2022]
Abstract
Sequence-specific gene silencing using small interfering RNA (siRNA) provides a potent and specific method for gene expression, thus is now being evaluated in clinical trials as a novel therapeutic strategy. As a results, there has been a significant surge of interest in the application of siRNA in therapeutics as a means of silencing the specific gene function. However, for siRNA technology to be valuable and effective, the development of efficient siRNA delivery strategy is essential for improving biological activities such as stability, cellular uptake, sequence-specificity, devoid of nonspecific knockdown and toxic side effects. Accordingly, a number of delivery systems, both viral and nonviral, have been reported and some of them successfully used for the introduction of siRNA into cells both in vitro and in vivo. Here, we discuss the current understanding of synthetic siRNA delivery mechanism and strategies of siRNA delivery by non-viral polymeric vehicles which are currently used in vitro and in vivo.
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35
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Forbes K, Desforges M, Garside R, Aplin JD, Westwood M. Methods for siRNA-mediated reduction of mRNA and protein expression in human placental explants, isolated primary cells and cell lines. Placenta 2008; 30:124-9. [PMID: 19012963 PMCID: PMC2634981 DOI: 10.1016/j.placenta.2008.10.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 09/23/2008] [Accepted: 10/07/2008] [Indexed: 11/29/2022]
Abstract
The use of RNA interference (RNAi) to deplete individual proteins from cells or tissue has revolutionised our ability to characterise gene function. The placenta is an attractive target for studies in which the role of specific proteins can be compared with cell culture models and explanted villous tissue where physiological function can be maintained ex vivo. In this study, we compared a variety of commercially available reagents and approaches to define methods for efficient delivery of siRNA to placental cells. Protocols optimised using fluorescently-labelled siRNA were subsequently tested using siRNA sequences that target placental alkaline phosphatase (PLAP), chosen because of its high abundance in trophoblast. mRNA abundance was assayed using qRT-PCR, and the effect on protein was examined using immunolocalisation. We report that different protocols are required for BeWo choriocarcinoma cells (nucleofection), primary cytotrophoblast cells (lipid-based transfection) and villous tissue explants (nucleofection). The results provide guidelines for optimal siRNA-mediated knockdown in these three models of the human placenta.
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Affiliation(s)
- K Forbes
- Maternal & Fetal Health Research Group, School of Clinical & Laboratory Sciences, University of Manchester, St. Mary's Hospital, Hathersage Road, Manchester M13 0JH, UK
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36
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Omidi Y, Hollins AJ, Drayton RM, Akhtar S. Polypropylenimine dendrimer-induced gene expression changes: The effect of complexation with DNA, dendrimer generation and cell type. J Drug Target 2008; 13:431-43. [PMID: 16308212 DOI: 10.1080/10611860500418881] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Polypropylenimine (PPI) dendrimers appear attractive non-viral vectors for the delivery of genes, antisense oligonucleotides, and small interfering RNA (siRNA). However, the effects of these synthetic gene delivery vectors on global gene expression are poorly understood. Here we have examined the toxicogenomics of generation 2 (DAB-8) and generation 3 (DAB-16) PPI dendrimers in two human cell lines. At concentrations and treatment protocols routinely used for gene and oligonucleotide transfection, PPI dendrimers alone elicited marked changes in endogenous gene expression in A431 epithelial cells. The extent of PPI-induced gene changes appeared to be dependent on the dendrimer generation as the number of genes affected was greater with G3 compared to G2 PPI dendrimers in A431 cells. The signature of DAB16-induced gene changes in A549 cells was different to those elicited in A431 cells implying a strong dependence on cell type. The DAB-16 polymer complexed with DNA (dendriplexes) also elicited marked gene expression changes in A549 cells but with a signature that was different from the polymer alone implying that dendriplexes are "recognised" by cells as chemical entities that are distinct from the polymer alone. Alterations in expression of a variety of gene ontologies were observed including those involved in defence responses, cell proliferation and apoptosis. Although there was a tendency for increased DNA damage in cells treated with DAB16 alone or its DNA dendriplexes as detected by the COMET assay, these differences were not statistically significant. These data show for the first time that PPI-dendrimers, separate from their capability as transfection reagents, can intrinsically alter the expression of many endogenous genes that could potentially lead to them exerting multiple biological effects in cells. The impact and consequences of polymer-induced gene changes should guide their rational use as delivery systems for gene-based therapeutics.
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Affiliation(s)
- Y Omidi
- Tabriz University of Medical Sciences, Department of Pharmaceutics, Tabriz, Iran
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37
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de Almeida RS, Keita D, Libeau G, Albina E. Structure and sequence motifs of siRNA linked with in vitro down-regulation of morbillivirus gene expression. Antiviral Res 2008; 79:37-48. [PMID: 18394725 DOI: 10.1016/j.antiviral.2008.01.159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2007] [Revised: 01/11/2008] [Accepted: 01/23/2008] [Indexed: 10/22/2022]
Abstract
The most challenging task in RNA interference is the design of active small interfering RNA (siRNA) sequences. Numerous strategies have been published to select siRNA. They have proved effective in some applications but have failed in many others. Nonetheless, all existing guidelines have been devised to select effective siRNAs targeting human or murine genes. They may not be appropriate to select functional sequences that target genes from other organisms like viruses. In this study, we have analyzed 62 siRNA duplexes of 19 bases targeting three genes of three morbilliviruses. In those duplexes, we have checked which features are associated with siRNA functionality. Our results suggest that the intramolecular secondary structure of the targeted mRNA contributes to siRNA efficiency. We also confirm that the presence of at least the sequence motifs U13, A or U19, as well as the absence of G13, cooperate to increase siRNA knockdown rates. Additionally, we observe that G11 is linked with siRNA efficacy. We believe that an algorithm based on these findings may help in the selection of functional siRNA sequences directed against viral genes.
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Abstract
Sequence-specific gene silencing using small interfering RNA (siRNA) is a Nobel prize-winning technology that is now being evaluated in clinical trials as a potentially novel therapeutic strategy. This article provides an overview of the major pharmaceutical challenges facing siRNA therapeutics, focusing on the delivery strategies for synthetic siRNA duplexes in vivo, as this remains one of the most important issues to be resolved. This article also highlights the importance of understanding the genocompatibility/toxicogenomics of siRNA delivery reagents in terms of their impact on gene-silencing activity and specificity. Collectively, this information is essential for the selection of optimally acting siRNA delivery system combinations for the many proposed applications of RNA interference.
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Affiliation(s)
- Saghir Akhtar
- SA Pharma, Sutton Coldfield, West Midlands, United Kingdom.
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39
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Solis CF, Guillén N. Silencing genes by RNA interference in the protozoan parasite Entamoeba histolytica. Methods Mol Biol 2008; 442:113-28. [PMID: 18369782 DOI: 10.1007/978-1-59745-191-8_9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Experimental procedures using the RNA interference (RNAi) approach have recently emerged as a powerful tool for gene silencing in eukaryotic microbes for which gene replacement techniques have not yet been developed. Our group has recently explored RNAi to knock down gene-specific expression in the protozoan parasite Entamoeba histolytica, through delivery of small interfering RNA (siRNA) oligonucleotides by the soaking approach. Standardized conditions for the soaking of E. histolytica trophozoites with siRNAs result in highly specific and significant silencing of parasite cognate genes. Real-time PCR analysis indicates that a 16-hour treatment with siRNAs usually results in half-extinction of target messenger RNA. Furthermore, Western blot analysis of trophozoite crude extracts with the use of specific antibodies shows a similar reduction of cognate protein levels after siRNA treatment.
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Affiliation(s)
- Carlos F Solis
- Unité de Biologie Cellulaire du Parasitisme, Institut Pasteur, Paris, France
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Hollins AJ, Omidi Y, Benter IF, Akhtar S. Toxicogenomics of drug delivery systems: Exploiting delivery system-induced changes in target gene expression to enhance siRNA activity. J Drug Target 2007; 15:83-8. [PMID: 17365277 DOI: 10.1080/10611860601151860] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Synthetic siRNAs are typically formulated with drug delivery systems (DDS) that improve cellular uptake for optimal gene silencing activity. Here, we show that two PAMAM dendrimer DDS, differing only in their structural architecture, elicit many different gene expression changes in human cells including opposing effects on the expression of epidermal growth factor receptor (EGFR), a gene targeted for silencing by siRNA. Despite providing similar improvements in siRNA uptake, these two formulations led to a approximately 10-fold variation in anti-EGFR siRNA activity. These data show that gene expression changes induced by DDS, separate from their ability to enhance cell uptake, determine 'apparent' siRNA potency and thus offer the possibility of tailoring delivery system-siRNA combinations for additive or synergistic effects on gene silencing.
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Affiliation(s)
- Andrew J Hollins
- Centre for Genome Based therapeutics, Cardiff University School of Pharmacy, Cardiff, CF10 3XF, UK
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41
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Oliveira S, Fretz MM, Høgset A, Storm G, Schiffelers RM. Photochemical internalization enhances silencing of epidermal growth factor receptor through improved endosomal escape of siRNA. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1211-7. [PMID: 17343820 DOI: 10.1016/j.bbamem.2007.01.013] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Revised: 01/09/2007] [Accepted: 01/11/2007] [Indexed: 01/13/2023]
Abstract
Photochemical internalization (PCI) has been employed as a tool for site-specific intracellular delivery of a variety of molecules. In this study, for the first time, PCI has been employed to facilitate the endosomal escape of small interfering RNA (siRNA) molecules, which are the functional mediators of RNA interference (RNAi). In order to interact with the machinery that will induce post-transcriptional gene silencing, siRNA molecules need to enter the cytoplasm of the cells. This study shows that one of the important rate-limiting steps of siRNA silencing efficiency is the ability of siRNA molecules and/or complexes to escape from the endosomes into the cytosol of the cells. The target of this study, the epidermal growth factor receptor (EGFR), is known as an attractive target for cancer therapy. In this study, a 10-fold increased efficiency in knockdown of the EGFR protein was obtained when anti-EGFR siRNA treatment was combined with PCI as compared to siRNA treatment alone. The fact that this combined treatment resulted in a stronger silencing efficiency indicates that lower doses of siRNA can be used when PCI is employed to augment siRNA delivery. Lowering doses of siRNA would prevent saturation of the RNAi machinery and reduce off-target effects. In addition, local illumination of target tissue would only induce PCI in the desired cells, which can further increase the specificity of the treatment, supporting PCI as an attractive strategy to improve siRNA silencing efficiency.
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Affiliation(s)
- Sabrina Oliveira
- Department Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, PO Box 80.082, 3508 TB Utrecht, The Netherlands
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42
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Tsutsumi T, Hirayama F, Uekama K, Arima H. Evaluation of polyamidoamine dendrimer/alpha-cyclodextrin conjugate (generation 3, G3) as a novel carrier for small interfering RNA (siRNA). J Control Release 2007; 119:349-59. [PMID: 17477999 DOI: 10.1016/j.jconrel.2007.03.013] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Revised: 03/14/2007] [Accepted: 03/21/2007] [Indexed: 12/12/2022]
Abstract
As the first step toward an evaluation of the potential use of the PAMAM dendrimer (G3) conjugate with alpha-cyclodextrin (alpha-CDE) for a small interfering RNA (siRNA) carrier, the ternary complexes of alpha-CDE or the transfection reagents such as Lipofactamine 2000 (L2), TransFast (TF) and Lipofectin (LF) with plasmid DNA (pDNA) and siRNA were prepared, and their RNAi effects, cytotoxicity, physicochemical properties and intracellular distribution were compared. Here the pGL2 control vector (pGL2) and pGL3 control vector (pGL3) encoding the firefly luciferase gene and the two corresponding siRNAs (siGL2 and siGL3) were used. The ternary complexes of pGL3/siGL3/alpha-CDE showed the potent RNAi effects with negligible cytotoxicity compared to those of the transfection reagents in various cells. alpha-CDE strongly interacted with both pDNA and siRNA, and suppressed siRNA degradation by serum, compared to those of the transfection reagents. alpha-CDE allowed fluorescent labeled siRNA to distribute in cytoplasm, whereas the transfection reagents resided in both nucleus and cytoplasm in NIH3T3 cells. Furthermore, the binary complex of siRNA/alpha-CDE provided the significant RNAi effect in NIH3T3 cells transiently and stably expressing luciferase gene. These results suggest that alpha-CDE may be utilized as a novel carrier for siRNA.
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Affiliation(s)
- Toshihito Tsutsumi
- Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1, Oe-honmachi, Kumamoto 862-0973, Japan
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43
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Akhtar S, Benter I. Toxicogenomics of non-viral drug delivery systems for RNAi: potential impact on siRNA-mediated gene silencing activity and specificity. Adv Drug Deliv Rev 2007; 59:164-82. [PMID: 17481774 DOI: 10.1016/j.addr.2007.03.010] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2007] [Accepted: 03/04/2007] [Indexed: 01/05/2023]
Abstract
RNA interference (RNAi) is an evolutionary conserved cellular process for the regulation of gene expression. In mammalian cells, RNAi is induced via short (21-23 nt) duplexes of RNA, termed small interfering RNA (siRNA), that can elicit highly sequence-specific gene silencing. However, synthetic siRNA duplexes are polyanionic macromolecules that do not readily enter cells and typically require the use of a delivery vector for effective gene silencing in vitro and in vivo. Choice of delivery system is usually made on its ability to enhance cellular uptake of siRNA. However, recent gene expression profiling (toxicogenomics) studies have shown that separate from their effects on cellular uptake, delivery systems can also elicit wide ranging gene changes in target cells that may impact on the 'off-target' effects of siRNA. Furthermore, if delivery systems also alter the expression of genes targeted for silencing, then siRNA activity may be compromised or enhanced depending on whether the target gene is up-regulated or down-regulated respectively. Citing recent examples from the literature, this article therefore reviews the toxicogenomics of non-viral delivery systems and highlights the importance of understanding the genomic signature of siRNA delivery reagents in terms of their impact on gene silencing activity and specificity. Such information will be essential in the selection of optimally acting siRNA-delivery system combinations for the many applications of RNA interference.
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Affiliation(s)
- Saghir Akhtar
- SA Pharma, Vesey Road 1, Sutton Coldfield, West Midlands, B73 5NP, United Kingdom.
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Yamagata M, Kawano T, Shiba K, Mori T, Katayama Y, Niidome T. Structural advantage of dendritic poly(l-lysine) for gene delivery into cells. Bioorg Med Chem 2007; 15:526-32. [PMID: 17035030 DOI: 10.1016/j.bmc.2006.09.033] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Revised: 09/15/2006] [Accepted: 09/16/2006] [Indexed: 11/26/2022]
Abstract
This study aimed to investigate the relationships between structures of gene carrier molecules and their activities for gene delivery into cells. We compared 2 types of poly(L-lysine) as carriers, that is, dendritic poly(L-lysine) (KG6) and linear poly(L-lysine) (PLL). KG6 formed a neutral DNA complex, and its DNA compaction level was weaker than that of PLL. The amount of DNA binding and uptake into cells mediated by PLL was 4-fold higher than that with KG6. However, KG6-mediated gene expression was 100-fold higher than that by PLL. Since pK(a) values of terminal amines of KG6 were lowered even though small amounts of DNA were internalized into cells, sufficient DNA amounts for effective gene expression escaped to the cytosol due to the proton sponge effect in the endosome. In addition, weakly compacted DNA with KG6 was advantageous in accessing RNA polymerase in the cell nucleus. On the other hand, PLL did not show the proton sponge effect in the endosome and resulted in strong compaction of DNA. Even though large DNA amounts were internalized into cells, most of the DNA would not take part in gene expression systems in the nucleus. Amount of induced cytokine production after intravenous injection of DNA complexes with KG6 and PLL was low, and was similar to the case when DNA was injected alone. Therefore, no significant difference in effects on cytokine production was observed between KG6 and PLL.
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Affiliation(s)
- Masato Yamagata
- Department of Applied Chemistry, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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Turner JJ, Jones SW, Moschos SA, Lindsay MA, Gait MJ. MALDI-TOF mass spectral analysis of siRNA degradation in serum confirms an RNAse A-like activity. MOLECULAR BIOSYSTEMS 2007; 3:43-50. [PMID: 17216055 PMCID: PMC2682774 DOI: 10.1039/b611612d] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Synthetic siRNA duplexes are used widely as reagents for silencing of mRNA targets in cells and are being developed for in vivo use. Serum stability is a major concern if siRNA is to be used for therapeutic delivery within blood circulation. We have developed the use of MALDI-TOF mass spectrometry as a rapid and convenient analytical tool to identify the most vulnerable sites within siRNA to serum degradation. Using this approach, we found that one siRNA duplex (Dh3) with UpA sequences close to one end was particularly vulnerable to rapid cleavage. This produced a fragment of mass consistent with the presence of a 2',3'-cyclic phosphate that was slowly hydrolysed to a 2'-(3'-)phosphate on extended incubation. Substitution of these sites with 2'-O-methyl U residues prevented cleavage and confirmed that the major pathway for initial degradation is via cleavage by an RNAse A-like activity. Mass spectral analysis was used to follow the serum degradation of siRNA over more prolonged periods to show the accumulation of many fragments, almost all showing cleavage following pyrimidine nucleoside residues. Overall, the MALDI-TOF mass spectral analysis technique should prove useful for preliminary screening of the serum stability of siRNA duplexes and for identification of the most vulnerable cleavage sites.
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Affiliation(s)
- John J. Turner
- Medical Research Council, Laboratory of Molecular Biology, Hills Road, Cambridge, UK CB2 2QH
| | - Simon W. Jones
- AstraZeneca R & D, Respiratory and Inflammation Research Area, Alderley park, Macclesfield, Cheshire, UK
| | - Sterghios A. Moschos
- Biopharmaceutics Research Group, Airways Disease, National Heart and Lung Institute, Imperial College, London, UK SW3 6LY
| | - Mark A. Lindsay
- Biopharmaceutics Research Group, Airways Disease, National Heart and Lung Institute, Imperial College, London, UK SW3 6LY
| | - Michael J. Gait
- Medical Research Council, Laboratory of Molecular Biology, Hills Road, Cambridge, UK CB2 2QH
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Fichou Y, Férec C. The potential of oligonucleotides for therapeutic applications. Trends Biotechnol 2006; 24:563-70. [PMID: 17045686 DOI: 10.1016/j.tibtech.2006.10.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2006] [Revised: 08/21/2006] [Accepted: 10/03/2006] [Indexed: 12/15/2022]
Abstract
Viral-derived particles have been widely used and described in gene therapy clinical trials. Although substantial results have been achieved, major safety issues have also arisen. For more than a decade, oligonucleotides have been seen as an alternative to gene complementation by viral vectors or DNA plasmids, either to correct the genetic defect or to silence gene expression. The development of RNA interference has strengthened the potential of this approach. Recent clinical trials have also tested the ability of aptamer molecules and decoy oligonucleotides to sequestrate pathogenic proteins. Here, we review the potential of oligonucleotides in gene therapy, outline what has already been accomplished, and consider what remains to be done.
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Affiliation(s)
- Yann Fichou
- Inserm U613, Université de Bretagne Occidentale, 46 rue Félix Le Dantec, 29275 Brest Cedex, France
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Dhume A, Lu S, Horowits R. Targeted disruption of N-RAP gene function by RNA interference: a role for N-RAP in myofibril organization. ACTA ACUST UNITED AC 2006; 63:493-511. [PMID: 16767749 DOI: 10.1002/cm.20141] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
N-RAP is a muscle-specific protein concentrated in myofibril precursors during sarcomere assembly and at intercalated disks in adult heart. We used RNA interference to achieve a targeted decrease in N-RAP transcript and protein levels in primary cultures of embryonic mouse cardiomyocytes. N-RAP transcript levels were decreased by approximately 70% within 2 days following transfection with N-RAP specific siRNA. N-RAP protein levels steadily decreased over several days, reaching approximately 50% of control levels within 6 days. N-RAP protein knockdown was associated with decreased myofibril assembly, as assessed by alpha-actinin organization into mature striations. Transcripts encoding N-RAP binding proteins associated with assembling or mature myofibrils, such as alpha-actinin, Krp1, and muscle LIM protein, were expressed at normal levels during N-RAP protein knockdown, and alpha-actinin and Krp-1 protein levels were also unchanged. Transcripts encoding muscle myosin heavy chain and nonmuscle myosin heavy chain IIB were also expressed at relatively normal levels. However, decreased N-RAP protein levels were associated with dramatic changes in the encoded myosin proteins, with muscle myosin heavy chain levels increasing and nonmuscle myosin heavy chain IIB decreasing. N-RAP transcript and protein levels recovered to normal by days 6 and 7, respectively, and the changes in myofibril organization and myosin heavy chain isoform levels were reversed. Our data indicate that we can achieve transient N-RAP protein knockdown using the RNA interference technique and that alpha-actinin organization into myofibrils in cardiomyocytes is closely linked to N-RAP protein levels. Finally, N-RAP protein levels regulate the balance between nonmuscle myosin IIB and muscle myosin by post-trancriptional mechanisms.
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Affiliation(s)
- Ashwini Dhume
- Laboratory of Muscle Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health (Department of Health and Human Services), Bethesda, MD 20892, USA
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Spee B, Jonkers MDB, Arends B, Rutteman GR, Rothuizen J, Penning LC. Specific down-regulation of XIAP with RNA interference enhances the sensitivity of canine tumor cell-lines to TRAIL and doxorubicin. Mol Cancer 2006; 5:34. [PMID: 16953886 PMCID: PMC1569868 DOI: 10.1186/1476-4598-5-34] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2005] [Accepted: 09/05/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Apoptosis resistance occurs in various tumors. The anti-apoptotic XIAP protein is responsible for inhibiting apoptosis by reducing caspase-3 activation. Our aim is to evaluate whether RNA inhibition against XIAP increases the sensitivity of canine cell-lines for chemotherapeutics such as TRAIL and doxorubicin. We used small interfering RNA's (siRNA) directed against XIAP in three cell-lines derived from bile-duct epithelia (BDE), mammary carcinoma (P114), and osteosarcoma (D17). These cell-lines represent frequently occurring canine cancers and are highly comparable to their human counterparts. XIAP down-regulation was measured by means of quantitative PCR (Q-PCR) and Western blotting. The XIAP depleted cells were treated with a serial dilution of TRAIL or doxorubicin and compared to mock- and nonsense-treated controls. Viability was measured with a MTT assay. RESULTS All XIAP siRNA treated cell-lines showed a mRNA down-regulation over 80 percent. Western blot analysis confirmed mRNA measurements. No compensatory effect of IAP family members was seen in XIAP depleted cells. The sensitivity of XIAP depleted cells for TRAIL was highest in BDE cells with an increase in the ED50 of 14-fold, compared to mock- and nonsense-treated controls. The sensitivity of P114 and D17 cell-lines increased six- and five-fold, respectively. Doxorubicin treatment in XIAP depleted cells increased sensitivity in BDE cells more than eight-fold, whereas P114 and D17 cell-lines showed an increase in sensitivity of three- and five-fold, respectively. CONCLUSION XIAP directed siRNA's have a strong sensitizing effect on TRAIL-reduced cell-viability and a smaller but significant effect with the DNA damaging drug doxorubicin. The increase in efficacy of chemotherapeutics with XIAP depletion provides the rationale for the use of XIAP siRNA's in insensitive canine tumors.
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Affiliation(s)
- Bart Spee
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, P.O. BOX 80.154, 3508 TD Utrecht, The Netherlands
| | - Martijn DB Jonkers
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, P.O. BOX 80.154, 3508 TD Utrecht, The Netherlands
| | - Brigitte Arends
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, P.O. BOX 80.154, 3508 TD Utrecht, The Netherlands
| | - Gerard R Rutteman
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, P.O. BOX 80.154, 3508 TD Utrecht, The Netherlands
| | - Jan Rothuizen
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, P.O. BOX 80.154, 3508 TD Utrecht, The Netherlands
| | - Louis C Penning
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, P.O. BOX 80.154, 3508 TD Utrecht, The Netherlands
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50
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Coumoul X, Deng CX. RNAi in mice: a promising approach to decipher gene functions in vivo. Biochimie 2006; 88:637-43. [PMID: 16426724 DOI: 10.1016/j.biochi.2005.11.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Accepted: 11/29/2005] [Indexed: 10/25/2022]
Abstract
RNA interference (RNAi) is a simple and powerful tool widely used to study gene functions in many species. Vector-based systems using RNA polymerase III promoters have been developed to achieve stable expression of small interfering RNA (siRNA) or small hairpin RNA (shRNA) in mammalian cells. Recent investigations demonstrated that when, combined with the Cre-loxP system, the vector-based RNAi can be used to achieve conditional or tissue specific knockdown of endogenous genes with high efficiency in mice. Here, we review these recent progresses and discuss the advantages, limitations and future development of this emerging technology.
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Affiliation(s)
- Xavier Coumoul
- INSERM UMR-S 490, Unite de Toxicologie Moléculaire, 45, rue des Saints-Pères, 75270 Paris cedex 06, France.
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