1
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Tamez A, Nilsson L, Mihailescu MR, Evanseck JD. Parameterization of the miniPEG-Modified γPNA Backbone: Toward Induced γPNA Duplex Dissociation. J Chem Theory Comput 2023. [PMID: 37195939 DOI: 10.1021/acs.jctc.2c01163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
γ-Modified peptide nucleic acids (γPNAs) serve as potential therapeutic agents against genetic diseases. Miniature poly(ethylene glycol) (miniPEG) has been reported to increase solubility and binding affinity toward genetic targets, yet details of γPNA structure and dynamics are not understood. Within our work, we parameterized missing torsional and electrostatic terms for the miniPEG substituent on the γ-carbon atom of the γPNA backbone in the CHARMM force field. Microsecond timescale molecular dynamics simulations were carried out on six miniPEG-modified γPNA duplexes from NMR structures (PDB ID: 2KVJ). Three NMR models for the γPNA duplex (PDB ID: 2KVJ) were simulated as a reference for structural and dynamic changes captured for the miniPEG-modified γPNA duplex. Principal component analysis performed on the γPNA backbone atoms identified a single isotropic conformational substate (CS) for the NMR simulations, whereas four anisotropic CSs were identified for the ensemble of miniPEG-modified γPNA simulations. The NMR structures were found to have a 23° helical bend toward the major groove, consistent with our simulated CS structure of 19.0°. However, a significant difference between simulated methyl- and miniPEG-modified γPNAs involved the opportunistic invasion of miniPEG through the minor and major groves. Specifically, hydrogen bond fractional analysis showed that the invasion was particularly prone to affect the second G-C base pair, reducing the Watson-Crick base pair hydrogen bond by 60% over the six simulations, whereas the A-T base pairs decreased by only 20%. Ultimately, the invasion led to base stack reshuffling, where the well-ordered base stacking was reduced to segmented nucleobase stacking interactions. Our 6 μs timescale simulations indicate that duplex dissociation suggests the onset toward γPNA single strands, consistent with the experimental observation of decreased aggregation. To complement the insight of miniPEG-modified γPNA structure and dynamics, the new miniPEG force field parameters allow for further exploration of such modified γPNA single strands as potential therapeutic agents against genetic diseases.
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Affiliation(s)
- Angel Tamez
- Center for Computational Sciences and the Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, United States
| | - Lennart Nilsson
- Department of Biosciences and Nutrition, Karolinska Institute, Solnavägen 1, 171 77 Solna, Sweden
| | - Mihaela-Rita Mihailescu
- Center for Computational Sciences and the Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, United States
| | - Jeffrey D Evanseck
- Center for Computational Sciences and the Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, United States
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2
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Dhami I, Thadke SA, Ly DH. Development of the Right- and Left-Handed Gamma Peptide Nucleic Acid Building Blocks for On-Resin Chemical Functionalization. J Org Chem 2022; 87:13873-13881. [PMID: 36190146 DOI: 10.1021/acs.joc.2c01560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Gamma peptide nucleic acids (PNAs) are a promising class of nucleic acid mimics that adopt either a right- or left-handed helical motif as individual strands and hybridize to DNA or RNA with high affinity and sequence specificity, or not at all, depending on the helical sense. They are attractive as antisense and antigene reagents, as well as building blocks for molecular self-assembly; however, they have not been widely adopted due to their relatively poor biophysical attributes and the challenge in chemical modifications. Here, we report the development of a set of universal monomers, four each for both the right- and left-handed conformers, that permit rapid and selective on-resin chemical functionalization and diversification. The system is modular, permitting incorporation of different chemical groups in the backbone without causing adverse effects on hybridization. The approach overcomes the need to prepare a new set of monomers each time a different chemical group is introduced in the backbone. The newly added synthetic flexibility, along with superior hybridization property, recognition orthogonality, and helical sense translational capability, significantly expands the scope of gamma PNA in biology, biotechnology, and molecular engineering.
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Affiliation(s)
- Isha Dhami
- Department of Chemistry and Institute for Bimolecular Design and Discovery (IBD), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Shivaji A Thadke
- Department of Chemistry and Institute for Bimolecular Design and Discovery (IBD), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Danith H Ly
- Department of Chemistry and Institute for Bimolecular Design and Discovery (IBD), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
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3
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Gaddam RR, Dhuri K, Kim YR, Jacobs JS, Kumar V, Li Q, Irani K, Bahal R, Vikram A. γ Peptide Nucleic Acid-Based miR-122 Inhibition Rescues Vascular Endothelial Dysfunction in Mice Fed a High-Fat Diet. J Med Chem 2022; 65:3332-3342. [PMID: 35133835 PMCID: PMC8883473 DOI: 10.1021/acs.jmedchem.1c01831] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
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The blood levels
of microRNA-122 (miR-122) is associated with the
severity of cardiovascular disorders, and targeting it with efficient
and safer miR inhibitors could be a promising approach. Here, we report
the generation of a γ-peptide nucleic acid (γPNA)-based
miR-122 inhibitor (γP-122-I) that rescues vascular endothelial
dysfunction in mice fed a high-fat diet. We synthesized diethylene
glycol-containing γP-122-I and found that its systemic administration
counteracted high-fat diet (HFD)-feeding-associated increase in blood
and aortic miR-122 levels, impaired endothelial function, and reduced
glycemic control. A comprehensive safety analysis established that
γP-122-I affects neither the complete blood count nor biochemical
tests of liver and kidney functions during acute exposure. In addition,
long-term exposure to γP-122-I did not change the overall adiposity,
or histology of the kidney, liver, and heart. Thus, γP-122-I
rescues endothelial dysfunction without any evidence of toxicity in vivo and demonstrates the suitability of γPNA technology
in generating efficient and safer miR inhibitors.
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Affiliation(s)
- Ravinder Reddy Gaddam
- Department of Internal Medicine, Carver College of Medicine University of Iowa, Iowa City, Iowa 52242, United States
| | - Karishma Dhuri
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Young-Rae Kim
- Department of Internal Medicine, Carver College of Medicine University of Iowa, Iowa City, Iowa 52242, United States
| | - Julia S Jacobs
- Department of Internal Medicine, Carver College of Medicine University of Iowa, Iowa City, Iowa 52242, United States
| | - Vikas Kumar
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Qiuxia Li
- Department of Internal Medicine, Carver College of Medicine University of Iowa, Iowa City, Iowa 52242, United States
| | - Kaikobad Irani
- Department of Internal Medicine, Carver College of Medicine University of Iowa, Iowa City, Iowa 52242, United States
| | - Raman Bahal
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Ajit Vikram
- Department of Internal Medicine, Carver College of Medicine University of Iowa, Iowa City, Iowa 52242, United States
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4
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Dhuri K, Vyas RN, Blumenfeld L, Verma R, Bahal R. Nanoparticle Delivered Anti-miR-141-3p for Stroke Therapy. Cells 2021; 10:cells10051011. [PMID: 33922958 PMCID: PMC8145654 DOI: 10.3390/cells10051011] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/20/2021] [Accepted: 04/23/2021] [Indexed: 01/14/2023] Open
Abstract
Ischemic stroke and factors modifying ischemic stroke responses, such as social isolation, contribute to long-term disability worldwide. Several studies demonstrated that the aberrant levels of microRNAs contribute to ischemic stroke injury. In prior studies, we established that miR-141-3p increases after ischemic stroke and post-stroke isolation. Herein, we explored two different anti-miR oligonucleotides; peptide nucleic acid (PNAs) and phosphorothioates (PS) for ischemic stroke therapy. We used US FDA approved biocompatible poly (lactic-co-glycolic acid) (PLGA)-based nanoparticle formulations for delivery. The PNA and PS anti-miRs were encapsulated in PLGA nanoparticles by double emulsion solvent evaporation technique. All the formulated nanoparticles showed uniform morphology, size, distribution, and surface charge density. Nanoparticles also exhibited a controlled nucleic acid release profile for 48 h. Further, we performed in vivo studies in the mouse model of ischemic stroke. Ischemic stroke was induced by transient (60 min) occlusion of middle cerebral artery occlusion followed by a reperfusion for 48 or 72 h. We assessed the blood-brain barrier permeability of PLGA NPs containing fluorophore (TAMRA) anti-miR probe after systemic delivery. Confocal imaging shows uptake of fluorophore tagged anti-miR in the brain parenchyma. Next, we evaluated the therapeutic efficacy after systemic delivery of nanoparticles containing PNA and PS anti-miR-141-3p in mice after stroke. Post-treatment differentially reduced both miR-141-3p levels in brain tissue and infarct injury. We noted PNA-based anti-miR showed superior efficacy compared to PS-based anti-miR. Herein, we successfully established that nanoparticles encapsulating PNA or PS-based anti-miRs-141-3p probes could be used as a potential treatment for ischemic stroke.
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Affiliation(s)
- Karishma Dhuri
- School of Pharmacy, University of Connecticut, Storrs, CT 06269, USA;
| | - Rutesh N. Vyas
- Department of Neurosciences, UConn Health, Farmington, CT 06032, USA; (R.N.V.); (L.B.)
| | - Leslie Blumenfeld
- Department of Neurosciences, UConn Health, Farmington, CT 06032, USA; (R.N.V.); (L.B.)
| | - Rajkumar Verma
- Department of Neurosciences, UConn Health, Farmington, CT 06032, USA; (R.N.V.); (L.B.)
- Correspondence: (R.V.); (R.B.)
| | - Raman Bahal
- School of Pharmacy, University of Connecticut, Storrs, CT 06269, USA;
- Correspondence: (R.V.); (R.B.)
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5
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Das A, Pradhan B. Evolution of peptide nucleic acid with modifications of its backbone and application in biotechnology. Chem Biol Drug Des 2020; 97:865-892. [PMID: 33314595 DOI: 10.1111/cbdd.13815] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/17/2020] [Accepted: 12/05/2020] [Indexed: 01/23/2023]
Abstract
Peptide nucleic acids (PNAs) are getting prodigious interest currently in the biomedical and diagnostic field as an extremely powerful tool because of their potentiality to hybridize with natural nucleic acids. Although PNA has strong affinity and sequence specificity to DNA/RNA, there is a considerable ongoing effort to further enhance their special chemical and biological properties for potential application in numerous fields, notably in the field of therapeutics. The toolbox for backbone modified PNAs synthesis has been extended substantially in recent decades, providing a more efficient synthesis of peptides with numerous scaffolds and modifications. This paper reviews the various strategies that have been developed so far for the modification of the PNA backbone, challenging the search for new PNA systems with improved chemical and physical properties lacking in the original aegPNA backbone. The various practical issues and limitations of different PNA systems are also summarized. The focus of this review is on the evolution of PNA by its backbone modification to improve the cellular uptake, sequence specificity, and compatibility of PNA to bind to DNA/RNA. Finally, an insight was also gained into major applications of backbone modified PNAs for the development of biosensors.
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Affiliation(s)
- Anuradha Das
- National Institute of Science Education and Research Bhubaneswar (HBNI), Bhubaneswar, India
| | - Biswaranjan Pradhan
- S. K. Dash Center of Excellence of Biosciences and Engineering & Technology, Indian Institute of Technology Bhubaneswar, Bhubaneswar, India
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6
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Verona MD, Verdolino V, Palazzesi F, Corradini R. Focus on PNA Flexibility and RNA Binding using Molecular Dynamics and Metadynamics. Sci Rep 2017; 7:42799. [PMID: 28211525 PMCID: PMC5314342 DOI: 10.1038/srep42799] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 01/13/2017] [Indexed: 12/20/2022] Open
Abstract
Peptide Nucleic Acids (PNAs) can efficiently target DNA or RNA acting as chemical tools for gene regulation. Their backbone modification and functionalization is often used to increase the affinity for a particular sequence improving selectivity. The understanding of the trading forces that lead the single strand PNA to bind the DNA or RNA sequence is preparatory for any further rational design, but a clear and unique description of this process is still not complete. In this paper we report further insights into this subject, by a computational investigation aiming at the characterization of the conformations of a single strand PNA and how these can be correlated to its capability in binding DNA/RNA. Employing Metadynamics we were able to better define conformational pre-organizations of the single strand PNA and γ-modified PNA otherwise unrevealed through classical molecular dynamics. Our simulations driven on backbone modified PNAs lead to the conclusion that this γ-functionalization affects the single strand preorganization and targeting properties to the DNA/RNA, in agreement with circular dichroism (CD) spectra obtained for this class of compounds. MD simulations on PNA:RNA dissociation and association mechanisms allowed to reveal the critical role of central bases and preorganization in the binding process.
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Affiliation(s)
| | - Vincenzo Verdolino
- Department of Chemistry and Applied Biosciences, ETH Zurich, c/o Università della Svizzera Italiana Campus, 6900 Lugano, Switzerland
- Facoltà di Informatica, Instituto di Scienze Computazionali, Università della Svizzera Italiana, 6900 Lugano, Switzerland
| | - Ferruccio Palazzesi
- Department of Chemistry and Applied Biosciences, ETH Zurich, c/o Università della Svizzera Italiana Campus, 6900 Lugano, Switzerland
- Facoltà di Informatica, Instituto di Scienze Computazionali, Università della Svizzera Italiana, 6900 Lugano, Switzerland
| | - Roberto Corradini
- Dipartimento di Chimica, University of Parma, Italy, 43124, Italy
- National Institute for Biostructures and Biosystems (INBB)-Viale delle Medaglie d’Oro, 305, 00136 Roma, Italy
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7
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Gupta A, Bahal R, Gupta M, Glazer PM, Saltzman WM. Nanotechnology for delivery of peptide nucleic acids (PNAs). J Control Release 2016; 240:302-311. [PMID: 26776051 DOI: 10.1016/j.jconrel.2016.01.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 12/10/2015] [Accepted: 01/04/2016] [Indexed: 12/22/2022]
Abstract
Over the past three decades, peptide nucleic acids have been employed in numerous chemical and biological applications. Peptide nucleic acids possess enormous potential because of their superior biophysical properties, compared to other oligonucleotide chemistries. However, for therapeutic applications, intracellular delivery of peptide nucleic acids remains a challenge. In this review, we summarize the progress that has been made in delivering peptide nucleic acids to intracellular targets. In addition, we emphasize recent nanoparticle-based strategies for efficient delivery of conventional and chemically-modified peptides nucleic acids.
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Affiliation(s)
- Anisha Gupta
- Department of Therapeutic Radiology, Yale University, New Haven, CT, USA
| | - Raman Bahal
- Department of Therapeutic Radiology, Yale University, New Haven, CT, USA
| | - Meera Gupta
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA; Department of Chemical Engineering, Indian Institute of Technology-Delhi, New Delhi, India
| | - Peter M Glazer
- Department of Therapeutic Radiology, Yale University, New Haven, CT, USA; Department of Genetics, Yale University, New Haven, CT, USA.
| | - W Mark Saltzman
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA.
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8
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Bahal R, Quijano E, McNeer NA, Liu Y, Bhunia DC, Lopez-Giraldez F, Fields RJ, Saltzman WM, Ly DH, Glazer PM. Single-stranded γPNAs for in vivo site-specific genome editing via Watson-Crick recognition. Curr Gene Ther 2015; 14:331-42. [PMID: 25174576 DOI: 10.2174/1566523214666140825154158] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 07/14/2014] [Accepted: 07/15/2014] [Indexed: 01/13/2023]
Abstract
Triplex-forming peptide nucleic acids (PNAs) facilitate gene editing by stimulating recombination of donor DNAs within genomic DNA via site-specific formation of altered helical structures that further stimulate DNA repair. However, PNAs designed for triplex formation are sequence restricted to homopurine sites. Herein we describe a novel strategy where next generation single-stranded gamma PNAs (γPNAs) containing miniPEG substitutions at the gamma position can target genomic DNA in mouse bone marrow at mixed-sequence sites to induce targeted gene editing. In addition to enhanced binding, γPNAs confer increased solubility and improved formulation into poly(lactic-co-glycolic acid) (PLGA) nanoparticles for efficient intracellular delivery. Single-stranded γPNAs induce targeted gene editing at frequencies of 0.8% in mouse bone marrow cells treated ex vivo and 0.1% in vivo via IV injection, without detectable toxicity. These results suggest that γPNAs may provide a new tool for induced gene editing based on Watson-Crick recognition without sequence restriction.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Peter M Glazer
- Yale School of Medicine, Dept. of Therapeutic Radiology, P.O. Box 208040, New Haven, Connecticut 06520-8040, USA.
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9
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Moccia M, Adamo MFA, Saviano M. Insights on chiral, backbone modified peptide nucleic acids: Properties and biological activity. ARTIFICIAL DNA, PNA & XNA 2014; 5:e1107176. [PMID: 26752710 PMCID: PMC5329900 DOI: 10.1080/1949095x.2015.1107176] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 10/02/2015] [Accepted: 10/07/2015] [Indexed: 12/14/2022]
Abstract
PNAs are emerging as useful synthetic devices targeting natural miRNAs. In particular 3 classes of structurally modified PNAs analogs are herein described, namely α, β and γ, which differ by their backbone modification. Their mode and binding affinity for natural nucleic acids and their use in medicinal chemistry as potential miRNA binders is discussed.
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Affiliation(s)
- Maria Moccia
- Consiglio Nazionale delle Ricerche-Institute of Cristallography; Bari, Italy
| | - Mauro F A Adamo
- Centre for Synthesis and Chemical Biology (CSCB); Department of Pharmaceutical & Medicinal Chemistry; Royal College of Surgeons in Ireland; Dublin, Ireland
| | - Michele Saviano
- Consiglio Nazionale delle Ricerche-Institute of Cristallography; Bari, Italy
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10
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De Costa NTS, Heemstra JM. Differential DNA and RNA sequence discrimination by PNA having charged side chains. Bioorg Med Chem Lett 2014; 24:2360-3. [PMID: 24731279 DOI: 10.1016/j.bmcl.2014.03.059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 12/14/2022]
Abstract
PNA sequences modified with charged side chains were evaluated for base-pairing sequence selectivity under physiological conditions. PNA having negatively charged aspartic acid side chains shows higher selectivity with RNA, while PNA having positively charged lysine side chains shows higher selectivity with DNA. These observations provide insight into the binding selectivity of modified PNA in antisense and antigene applications.
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Affiliation(s)
- N Tilani S De Costa
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112, USA; Center for Cell and Genome Science, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA
| | - Jennifer M Heemstra
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112, USA; Center for Cell and Genome Science, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA.
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11
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Bahal R, McNeer NA, Ly DH, Saltzman WM, Glazer PM. Nanoparticle for delivery of antisense γPNA oligomers targeting CCR5. ARTIFICIAL DNA, PNA & XNA 2014; 4:49-57. [PMID: 23954968 DOI: 10.4161/adna.25628] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The development of a new class of peptide nucleic acids (PNAs), i.e., gamma PNAs (γPNAs), creates the need for a general and effective method for its delivery into cells for regulating gene expression in mammalian cells. Here we report the antisense activity of a recently developed hydrophilic and biocompatible diethylene glycol (miniPEG)-based gamma peptide nucleic acid called MPγPNAs via its delivery by poly(lactide-co-glycolide) (PLGA)-based nanoparticle system. We show that MPγPNA oligomers designed to bind to the selective region of chemokine receptor 5 (CC R5) transcript, induce potent and sequence-specific antisense effects as compared with regular PNA oligomers. In addition, PLGA nanoparticle delivery of MPγPNAs is not toxic to the cells. The findings reported in this study provide a combination of γPNA technology and PLGA-based nanoparticle delivery method for regulating gene expression in live cells via the antisense mechanism.
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12
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Sugiyama T, Kittaka A. Chiral peptide nucleic acids with a substituent in the N-(2-aminoethy)glycine backbone. Molecules 2012; 18:287-310. [PMID: 23271467 PMCID: PMC6269907 DOI: 10.3390/molecules18010287] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 12/19/2012] [Accepted: 12/19/2012] [Indexed: 11/16/2022] Open
Abstract
A peptide nucleic acid (PNA) is a synthetic nucleic acid mimic in which the sugar-phosphate backbone is replaced by a peptide backbone. PNAs hybridize to complementary DNA and RNA with higher affinity and superior sequence selectivity compared to DNA. PNAs are resistant to nucleases and proteases and have a low affinity for proteins. These properties make PNAs an attractive agent for biological and medical applications. To improve the antisense and antigene properties of PNAs, many backbone modifications of PNAs have been explored under the concept of preorganization. This review focuses on chiral PNAs bearing a substituent in the N-(2-aminoethyl)glycine backbone. Syntheses, properties, and applications of chiral PNAs are described.
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Affiliation(s)
- Toru Sugiyama
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan
- Author to whom correspondence should be addressed; E-Mail: ; Tel./Fax: +81-3-5465-8743
| | - Atsushi Kittaka
- Faculty of Pharmaceutical Sciences, Teikyo University, Kaga, Itabashi-ku, Tokyo 173-8605, Japan; E-Mail:
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