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Razavi Vakhshourpour S, Nateghpour M, Shahrokhi N, Motevalli Haghi A, Mohebali M, Hanifian H. Potential of RH5 Antisense on Plasmodium falciparum Proliferation Abatement. IRANIAN JOURNAL OF PARASITOLOGY 2022; 17:525-534. [PMID: 36694567 PMCID: PMC9825705 DOI: 10.18502/ijpa.v17i4.11280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 03/25/2022] [Indexed: 12/14/2022]
Abstract
Background Infections by Plasmodium falciparum, are becoming increasingly difficult to treat. Therefore, there is an urgent need for novel antimalarial agents' discovery against infection. In present study, we described a 2'-O-Methyl gapmer phosphorothioate oligonucleotide antisense targeting translation initiation region of 3D7 strain RH5 gene. Methods The study was conducted in Pasteur Institute of Iran in 2020. ODNs effects were measured by microscopic examination and real time RT-PCR. For microscopy, microplates were charged with 2'-OMe ODNs at different dilutions. Unsynchronized parasites were added to a total of 0.4 ml (0.4% parasitemia, 5% red blood cells), and slides were prepared. Proportion of infected cells was measured by counting at least 500 red blood cells. Results RH5 genes start codon regions selected as conserved region besed on alignment results. Gap-RH5-As which was complementary to sequence surrounding AUG RH5 start codon significantly reduced parasite growth (>90% at 50 nM) compared to sense sequence control (Gap-RH5-Se) (17%), (P<0.001). RH5 transcripts were dramatically reduced after exposed to ODNs at a concentration of 5-500 nM for 48 h. Conclusion Gemnosis delivery of a chimeric gapmer PS-ODN with 2'-OMe modifications at both sides had high antisense activity at low concentrations (10-100 nM) and shown a good efficiency to reach to target mRNA in human RBCs. Anti-parasite effect was correlated to reduction of target gene mRNA level. In addition, 2'-OMe ODNs free delivery is an effective way and does not need any carrier molecules or particles.
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Affiliation(s)
- Sepand Razavi Vakhshourpour
- Department of Medical Parasitology & Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Nateghpour
- Department of Medical Parasitology & Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Research Center of Quran, Hadith and Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Nader Shahrokhi
- Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran
| | - Afsaneh Motevalli Haghi
- Department of Medical Parasitology & Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Mohebali
- Department of Medical Parasitology & Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Haleh Hanifian
- Department of Medical Parasitology & Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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2
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Prabhu SR, Ware AP, Saadi AV. Erythrocyte miRNA regulators and malarial pathophysiology. INFECTION GENETICS AND EVOLUTION 2021; 93:105000. [PMID: 34252617 DOI: 10.1016/j.meegid.2021.105000] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 06/18/2021] [Accepted: 07/08/2021] [Indexed: 11/24/2022]
Abstract
Pathophysiology of Plasmodium falciparum and Plasmodium vivax in malaria vis a vis host and the parasite genome interactions has been deciphered recently to present the biology of cerebral malaria, severe anaemia and placental malaria. Small non-coding RNAs have exhibited their potential to be considered as indicators and regulators of diseases. The malarial pathologies and their associated mechanisms mediated by miRNAs and their role in haematopoiesis and red cell-related disorders are elucidated. Evidence of miRNA carrying exosome-like vesicles released during infection, delivering signals to endothelial cells enhancing gene expression, resulting in parasite sequestration and complications leading to pathologies of cerebral malaria are important breakthroughs. Pregnancy malaria showed Plasmodium surface antigen promoted erythrocyte sequestration in the placental intervillous space, provoking disease development and assorted complications. Syncytiotrophoblast-derived microparticles during pregnancy and fetus development may predict pathophysiological progression on account of their altered miRNA cargoes in malaria.
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Affiliation(s)
- Sowmya R Prabhu
- Department of Biotechnology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Akshay P Ware
- Department of Bioinformatics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Abdul Vahab Saadi
- Department of Biotechnology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India.
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Kolevzon N, Nasereddin A, Naik S, Yavin E, Dzikowski R. Use of peptide nucleic acids to manipulate gene expression in the malaria parasite Plasmodium falciparum. PLoS One 2014; 9:e86802. [PMID: 24466246 PMCID: PMC3899306 DOI: 10.1371/journal.pone.0086802] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 12/14/2013] [Indexed: 12/29/2022] Open
Abstract
One of the major concerns in treating malaria by conventional small drug molecules is the rapid emergence of drug resistance. Specific silencing of essential genes by antisense oliogomers has been proposed as an alternative approach that may result in antimalarial activity which is not associated with drug resistance. In addition, such an approach could be an important biological tool for studying many genes' function by reverse genetics. Here we present a novel methodology of using peptide nucleic acids (PNAs) as a useful tool for gene silencing in Plasmodium falciparum. PNAs, designed as specific antisense molecules, were conjugated to a cell penetrating peptide (CPP); namely, octa-D-lysine via the C-terminus, to allow facile delivery through cell membranes. PNAs added to P. falciparum cultures were found exclusively in infected erythrocytes and were eventually localized in nuclei of the parasites at all stages of intra erythrocytic development. We show that these PNAs specifically down regulated both a stably expressed transgene as well as an endogenous essential gene, which significantly reduced parasites' viability. This study paves the way for a simple approach to silence a variety of P. falciparum genes as means of deciphering their function and potentially to develop highly specific and potent antimalarial agents.
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Affiliation(s)
- Netanel Kolevzon
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Abed Nasereddin
- Department of Microbiology and Molecular Genetics, The institute for Medical Research Israel - Canada, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Shankar Naik
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Eylon Yavin
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ron Dzikowski
- Department of Microbiology and Molecular Genetics, The institute for Medical Research Israel - Canada, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
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4
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Platinum(II) and gold(I) complexes based on 1,1′-bis(diphenylphosphino)metallocene derivatives: Synthesis, characterization and biological activity of the gold complexes. J Organomet Chem 2012. [DOI: 10.1016/j.jorganchem.2012.08.034] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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5
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Cationic nanoemulsion as a delivery system for oligonucleotides targeting malarial topoisomerase II. Int J Pharm 2011; 416:402-9. [PMID: 21291974 DOI: 10.1016/j.ijpharm.2011.01.048] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 01/20/2011] [Accepted: 01/21/2011] [Indexed: 11/20/2022]
Abstract
A promising strategy based on the antisense oligonucleotides against the Plasmodium falciparum topoisomerase II has been considered using cationic nanoemulsion as oligonucleotide delivery system. Phosphodiester and chemically modified phosphorothioate oligonucleotides bearing negative charges were adsorbed on positively charged emulsion composed of medium chain triglycerides, egg lecithin, 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), and water, at different +/- charge ratios (positive charges from cationic lipid/negative charges from oligonucleotide): +0.5/-, +2/-, +4/- and +6/-. The physicochemical properties of the complexes were determined, as well as their stability in culture medium. Their interaction with erythrocytes through hemolysis, binding experiments and confocal microscopy were also evaluated. Finally, the in vitro evaluation of parasite growth and reinfection capacity was performed. The overall results showed that antisense oligonucleotides against P. falciparum topoisomerase II gene can be efficiently adsorbed onto a cationic nanoemulsion forming complexes. Whereas unloaded nanoemulsion displayed an hemolytic effect due to the presence of the cationic lipid, this was not the case of loaded nanoemulsion at low +/- ratios. Oligonucleotide-loaded nanoemulsions were found to be located inside the infected erythrocytes, inhibiting efficiently parasite growth (until 80%) and causing a delay in P. falciparum life cycle.
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6
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Sriwilaijaroen N, Boonma S, Attasart P, Pothikasikorn J, Panyim S, Noonpakdee W. Inhibition of Plasmodium falciparum proliferation in vitro by double-stranded RNA directed against malaria histone deacetylase. Biochem Biophys Res Commun 2009; 381:144-7. [PMID: 19338767 DOI: 10.1016/j.bbrc.2009.01.165] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Accepted: 01/23/2009] [Indexed: 10/21/2022]
Abstract
Acetylation and deacetylation of histones play important roles in transcription regulation, cell cycle progression and development events. The steady state status of histone acetylation is controlled by a dynamic equilibrium between competing histone acetylase and deacetylase (HDAC). We have used long PfHDAC-1 double-stranded (ds)RNA to interfere with its cognate mRNA expression and determined the effect on malaria parasite growth and development. Chloroquine- and pyrimethamine-resistant Plasmodium falciparum K1 strain was exposed to 1-25 microg of dsRNA/ml of culture for 48 h and growth was determined by [3H]-hypoxanthine incorporation and microscopic examination. Parasite culture treated with 10 microg/ml pfHDAC-1 dsRNA exhibited 47% growth inhibition when compared with either untreated control or culture treated with an unrelated dsRNA. PfHDAC-1 dsRNA specifically blocked maturation of trophozoite to schizont stages and decreased PfHDAC-1 transcript 44% in treated trophozoites. These results indicate the potential of HDAC-1 as a target for development of novel antimalarials.
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Affiliation(s)
- N Sriwilaijaroen
- Faculty of Medicine, Thammasat University (Rangsit Campus), Pathumthani 12120, Thailand
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7
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Militello KT, Refour P, Comeaux CA, Duraisingh MT. Antisense RNA and RNAi in protozoan parasites: working hard or hardly working? Mol Biochem Parasitol 2007; 157:117-26. [PMID: 18053590 DOI: 10.1016/j.molbiopara.2007.10.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Revised: 10/11/2007] [Accepted: 10/12/2007] [Indexed: 10/22/2022]
Abstract
The complex life cycles of many protozoan parasites require the ability to respond to environmental and developmental cues through regulated gene expression. Traditionally, parasitologists have investigated these mechanisms by identifying and characterizing proteins that are necessary for the regulated expression of the genetic material. Although often successful, it is clear that protein-mediated gene regulation is only part of a complex story in which RNA itself is endowed with regulatory functions. Herein, we review both the known and potential regulatory roles of two types of RNA pathways within protozoan parasites: the RNA interference pathway and natural antisense transcripts. A better understanding of the native role of these pathways will not only enhance our understanding of the biology of these organisms but also aid in the development of more robust tools for reverse genetic analysis in this post-genomic era.
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Affiliation(s)
- Kevin T Militello
- Department of Biology, State University of New York at Geneseo, Geneseo, NY, USA
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Noonpakdee W, Pothikasikorn J, Nimitsantiwong W, Wilairat P. Inhibition of Plasmodium falciparum proliferation in vitro by antisense oligodeoxynucleotides against malarial topoisomerase II. Biochem Biophys Res Commun 2003; 302:659-64. [PMID: 12646219 DOI: 10.1016/s0006-291x(03)00246-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The development of new effective antimalarial agents is urgently needed due to the ineffectiveness of current drug regimes on the most virulent human malaria parasite Plasmodium falciparum. Antisense (AS) oligodeoxynucleotides (ODNs) have shown promise as chemotherapeutic agents. Phosphorothioate AS ODNs against different regions of P. falciparum topoisomerase II gene were investigated. Chloroquine- and pyrimethamine-resistant P. falciparum K1 strain was exposed to phosphorothioate AS ODNs for 48 h and growth was determined by flow cytometric assay or by microscopic assay. Exogenous delivery of phosphorothioate AS ODNs between 0.01 and 0.5 microM significantly inhibited parasite growth compared with sense sequence controls suggesting sequence specific inhibition. This inhibition was shown to occur during maturation stages, with optimal inhibition being detected after 36 h. These results should prove useful in future designs of novel antimalarial agents.
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Affiliation(s)
- Wilai Noonpakdee
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
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Malhotra P, Dasaradhi PVN, Kumar A, Mohmmed A, Agrawal N, Bhatnagar RK, Chauhan VS. Double-stranded RNA-mediated gene silencing of cysteine proteases (falcipain-1 and -2) of Plasmodium falciparum. Mol Microbiol 2002; 45:1245-54. [PMID: 12207693 DOI: 10.1046/j.1365-2958.2002.03105.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Malaria remains a public health problem of enormous magnitude, affecting over 500 million people every year. Lack of success in the past in the development of new drug/vaccines has mainly been attributed to poor understanding of the functions of different parasite proteins. Recently, RNA interference (RNAi) has emerged as a simple and incisive technique to study gene functions in a variety of organisms. In this study, we report the results of RNAi by double-stranded RNA of cysteine protease genes (falcipain-1 and -2) in the malaria parasite, Plasmodium falciparum. Using RNAi directed towards falcipain genes, we demonstrate that blocking the expression of these genes results in severe morphological abnormalities in parasites, inhibition of parasite growth in vitro and substantial accumulation of haemoglobin in the parasite. The inhibitory effects produced by falcipain double-stranded (ds)RNAs are reminiscent of the effects observed upon administering E-64, a cysteine protease inhibitor. The parasites treated with falcipain's dsRNAs also show marked reduction in the levels of corresponding endogenous falcipain mRNAs. We also demonstrate that dsRNAs of falcipains are broken into short interference RNAs approximately 25 nucleotides in size, a characteristic of RNAi, which in turn activates sequence-specific nuclease activity in the malaria parasites. These results thus provide more evidence for the existence of RNAi in P. falciparum and also suggest possibilities for using RNAi as an effective tool to determine the functions of the genes identified from the P. falciparum genome sequencing project.
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Affiliation(s)
- Pawan Malhotra
- International Centre for Genetic Engineering and Biotechnology, PPO Box 10504, Aruna Asaf Ali Marg, New Delhi 110 065, India.
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10
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Abstract
The malaria parasite is a unicellular eukaryotic organism which, during the course of its complex life cycle, invades the red blood cells of its vertebrate host. As it grows and multiplies within its host blood cell, the parasite modifies the membrane permeability and cytosolic composition of the host cell. The intracellular parasite is enclosed within a so-called parasitophorous vacuolar membrane, tubular extensions of which radiate out into the host cell compartment. Like all eukaryote cells, the parasite has at its surface a plasma membrane, as well as having a variety of internal membrane-bound organelles that perform a range of functions. This review focuses on the transport properties of the different membranes of the malaria-infected erythrocyte, as well as on the role played by the various membrane transport systems in the uptake of solutes from the extracellular medium, the disposal of metabolic wastes, and the origin and maintenance of electrochemical ion gradients. Such systems are of considerable interest from the point of view of antimalarial chemotherapy, both as drug targets in their own right and as routes for targeting cytotoxic agents into the intracellular parasite.
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Affiliation(s)
- K Kirk
- Division of Biochemistry and Molecular Biology, Faculty of Science, Australian National University, Canberra, Australian Capital Territory, Australia.
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11
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Málaga S, Yoshida N. Targeted reduction in expression of Trypanosoma cruzi surface glycoprotein gp90 increases parasite infectivity. Infect Immun 2001; 69:353-9. [PMID: 11119524 PMCID: PMC97890 DOI: 10.1128/iai.69.1.353-359.2001] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A previous study had shown that the expression of gp90, a stage-specific surface glycoprotein of Trypanosoma cruzi metacyclic trypomastigotes, is inversely correlated with the parasite's ability to invade mammalian cells. By using antisense oligonucleotides complementary to a region of the gp90 gene implicated in host cell adhesion, we investigated whether the selective inhibition of gp90 synthesis affected the capacity of metacyclic forms to enter target cells. Parasites were incubated for 24 h with 20 microM PS1, a phosphorothioate oligonucleotide based on a sequence of the gp90 coding strand; PS2, the antisense counterpart of PS1; or PO2, the unmodified version of PS2 containing phosphodiester linkages, and the expression of surface molecules was analyzed by flow cytometry and immunoblotting using specific monoclonal antibodies. PS2 but not PS1 or PO2 inhibited the expression of gp90. Inhibition by PS2 was dose dependent. Northern blot analysis revealed that steady-state gp90 mRNA levels were diminished in PS2-treated parasites compared to untreated controls. Treatment with PS2 did not affect the expression of other metacyclic stage surface glycoproteins involved in parasite-host cell interaction, such as gp82 and the mucin-like gp35/50. Expression of gp90 was also inhibited by other phosphorothioate oligonucleotides targeted to the gp90 gene (PS4, PS5, PS6, and PS7) but not by PS3, with the same base composition as PS2 but a mismatched sequence. Parasites treated with PS2, PS4, or PS5 entered HeLa cells in significantly higher numbers than untreated controls, whereas the invasive capacity of PS1- and PS3-treated parasites was unchanged, confirming the inverse association between infectivity and gp90 expression.
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Affiliation(s)
- S Málaga
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
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12
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Wanidworanun C, Nagel RL, Shear HL. Antisense oligonucleotides targeting malarial aldolase inhibit the asexual erythrocytic stages of Plasmodium falciparum. Mol Biochem Parasitol 1999; 102:91-101. [PMID: 10477179 DOI: 10.1016/s0166-6851(99)00087-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A major obstacle in the global effort to control malaria is the paucity of anti-malarial drugs. This is compounded by the continuing emergence and spread of resistance to old and new anti-malarial drugs in the malarial parasites. Here we describe the anti-malarial effect of phosphorothioate antisense (AS) oligodeoxynucleotides (ODNs) targeting the aldolase enzyme of Plasmodium falciparum, using the asexual blood stages of the parasite grown in vitro. The blood stages of P. falciparum depend almost entirely on the energy produced by their own glycolysis. Aldolase, the fourth enzyme of the glycolytic pathway, is highly upregulated during the malarial 48-h life cycle. We found that the mRNA of this enzyme can be inhibited, in a sequence specific manner, using AS-ODN to the splice sites on the pre-mRNA of malarial aldolase. At the enzyme level, both specific AS-ODNs for the splice sites, as well as for the translation initiation site on mature mRNA, can inhibit aldolase enzyme activity within the trophozoites of P. falciparum. Furthermore, this downregulation of the malarial aldolase results in a reduction in the production of ATP within the parasite. Finally, the treatment reduces parasitemia. In summary, AS-ODNs targeting the aldolase gene of P. falciparum can interfere with the blood-stage life cycle of this parasite in vitro by inhibiting the expression of the enzyme aldolase which results in decreased malarial glycolysis and energy production. Thus, we conclude that blockade of the expression of malarial glycolytic enzymes using specific AS-ODNs has the potential of a new anti-malarial strategy.
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Affiliation(s)
- C Wanidworanun
- Department of Medicine, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, NY 10467, USA
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Kanagaratnam R, Misiura K, Rebowski G, Ramasamy R. Malaria merozoite surface protein antisense oligodeoxynucleotides lack antisense activity but function as polyanions to inhibit red cell invasion. Int J Biochem Cell Biol 1998; 30:979-85. [PMID: 9785462 DOI: 10.1016/s1357-2725(98)00051-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The effects on malaria parasite growth of antisense and sense oligodeoxynucleoside phosphorothioates based on a merozoite surface protein mRNA was examined. Specific antisense effects of the oligonucleotides could not be demonstrated over three cycles of schizogony or when added as a complex with cationic liposomes. Antisense and sense oligonucleotides however, inhibit merozoite invasion of red blood cells at similar concentrations to dextran sulphate, a polyanion, as determined by microscopy and [3H]hypoxanthine incorporation into DNA. Neutralisation of the negative charge on the oligonucleotides by binding to cationic lipid liposomes, prevented the inhibition of merozoite invasion. We postulate that oligonucleotides because of their polyanionic nature interfere with the binding of merozoites to receptors on red blood cells and that polyanions may be useful in malaria therapy.
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Affiliation(s)
- R Kanagaratnam
- Division of Life Sciences, Institute of Fundamental Studies, Kandy, Sri Lanka
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DeMoor JM, Vincent MD, Collins OM, Koropatnick J. Antisense nucleic acids targeted to the thymidylate synthase (TS) mRNA translation start site stimulate TS gene transcription. Exp Cell Res 1998; 243:11-21. [PMID: 9716444 DOI: 10.1006/excr.1998.4059] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Thymidylate synthase (TS) is a key enzyme in the synthesis of DNA and a target for cancer chemotherapeutic agents. Antisense TS nucleic acids may be useful in enhancing anticancer drug effectiveness. MCF-7 and HeLa cells were transfected with vectors expressing antisense TS RNA or with antisense oligodeoxynucleotides (AS-ODNs) to different TS mRNA regions. Antisense RNAs were targeted to 30 bases of the TS mRNA including part of the stem loop at the translation start site and to 30 bases spanning the exon1/exon2 boundary. AS-ODNs were targeted to the translation start site and the translation stop site. Antisense nucleic acids complementary to the translation start site (and not the exon1/exon2 boundary or translation stop site) significantly enhanced constitutive TS gene transcription. Therefore, TS mRNA sequences appear to be involved in a novel pathway controlling TS gene transcription. Induced transcription could hinder antisense-based attempts to inhibit TS and must be considered when designing such strategies.
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Affiliation(s)
- J M DeMoor
- The London Regional Cancer Centre, 790 Commissioners Road East, London, Ontario, N6A 4L6, Canada
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15
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Michienzi A, Conti L, Varano B, Prislei S, Gessani S, Bozzoni I. Inhibition of human immunodeficiency virus type 1 replication by nuclear chimeric anti-HIV ribozymes in a human T lymphoblastoid cell line. Hum Gene Ther 1998; 9:621-8. [PMID: 9551610 DOI: 10.1089/hum.1998.9.5-621] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Human immunodeficiency virus (HIV) infection represents one of the most challenging systems for gene therapy. Thanks to the extended knowledge of the molecular biology of the HIV life cycle, many different strategies have been developed including transdominant modifications of HIV proteins, RNA decoys, antisense RNA, ribozymes, and intracellular antibody fragments. In this paper, we have tested in a human T lymphoblastoid cell line the antiviral activity of ribozymes specifically designed to co-localize inside the nucleus with the Rev pre-mRNA before it is spliced and transported to the cytoplasm. This result was obtained by inserting the ribozyme in the spliceosomal U1 small nuclear RNA (snRNA) and in a derivative that has perfect complementarity with the 5' splice site of the Rev pre-mRNA. These ribozymes were tested in human T cell clones and were shown to be very efficient in inhibiting viral replication. Not only were the p24 levels in the culture medium drastically reduced but so were the intracellular HIV transcripts. Control disabled ribozymes enabled us to show the specificity of the ribozyme activity. Therefore, these constructs have potential utility for gene therapy of HIV-1 infection.
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Affiliation(s)
- A Michienzi
- Istituto Pasteur, Fondazione Cenci-Bolognetti, Department of Genetics and Molecular Biology, University La Sapienza, Rome, Italy
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Barker RH, Metelev V, Coakley A, Zamecnik P. Plasmodium falciparum: effect of chemical structure on efficacy and specificity of antisense oligonucleotides against malaria in vitro. Exp Parasitol 1998; 88:51-9. [PMID: 9501848 DOI: 10.1006/expr.1998.4192] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Antisense oligodeoxynucleotides (AS ODNs) have shown promise both as potential anti-malarial chemotherapeutic agents and as a means for identifying genes critical for parasite survival. Because conventional ODNs containing phosphodiester (PO) groups are subject to rapid nuclease degradation, ODNs with phosphorothioate (PS) groups are commonly used. However, at high concentration, these lose target specificity, and in some animal models, they become toxic. We compared a variety of chemical modifications (PO, PS, PO-PS hybrids, 2'-O-methyl-2'-deoxy chimeras) and structural modifications (sequence alterations favoring self-stabilizing loop formation) for their ability to inhibit Plasmodium falciparum malaria cultured in vitro. All modifications were done using an AS ODN sequence targeted against dihydrofolate reductase thymidylate synthase (DHFR). Inhibition by PO-PS hybrids containing as few as three PS groups at the 3'- and 5'-ends did not differ significantly from that obtained using compounds containing all-PS groups. Similarly, inhibition by PS chimeric compounds containing 2'-O-methyl modifications did not differ significantly from that of conventional PS compounds. In contrast, while inhibition by PO-PS hybrid chimeras did not differ significantly from that of all-PS compounds at low concentrations, at 1 microM they inhibited parasite growth 25% less (P < 0.001) than all-compounds or PS 2'-O-methyl-2'-deoxy chimeras. Extension of the nucleotide sequence to increase stem-loop formation yielded two compounds which inhibited parasite growth about 20% more than unmodified compounds, though this difference was not significant. Furthermore, most of this increase appears to correlate with the greater number of PS groups associated with the increased ODN length. We conclude that limiting the number of PS groups and inclusion of PO 2'-O-methyl groups may yield compounds with high antisense activity but low non-sequence-dependent effects. Such compounds are currently being tested in vivo.
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Affiliation(s)
- R H Barker
- Hybridon, Inc., Worcester, Massachusetts 01605, USA
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White DG, Maneewannakul K, von Hofe E, Zillman M, Eisenberg W, Field AK, Levy SB. Inhibition of the multiple antibiotic resistance (mar) operon in Escherichia coli by antisense DNA analogs. Antimicrob Agents Chemother 1997; 41:2699-704. [PMID: 9420041 PMCID: PMC164191 DOI: 10.1128/aac.41.12.2699] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The multiple antibiotic resistance operon (marORAB) in Escherichia coli controls intrinsic susceptibility and resistance to multiple, structurally different antibiotics and other noxious agents. A plasmid construct with marA cloned in the antisense direction reduced LacZ expression from a constitutively expressed marA::lacZ translational fusion and inhibited the induced expression of LacZ in cells bearing the wild-type repressed fusion. The marA antisense construction also decreased the multiple antibiotic resistance of a Mar mutant. Two antisense phosphorothioate oligonucleotides, one targeted to marO and the other targeted to marA of the mar operon, introduced by heat shock or electroporation reduced LacZ expression in the strain having the marA::lacZ fusion. One antisense oligonucleotide, tested against a Mar mutant of E. coli ML308-225, increased the bactericidal activity of norfloxacin. These studies demonstrate the efficacy of exogenously delivered antisense oligonucleotides targeted to the marRAB operon in inhibiting expression of this chromosomal regulatory locus.
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Affiliation(s)
- D G White
- Center for Adaptation Genetics and Drug Resistance, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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18
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Flores MV, Atkins D, Wade D, O'Sullivan WJ, Stewart TS. Inhibition of Plasmodium falciparum proliferation in vitro by ribozymes. J Biol Chem 1997; 272:16940-5. [PMID: 9202005 DOI: 10.1074/jbc.272.27.16940] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Catalytic RNA (ribozymes) suppressed the growth of the human malarial parasite Plasmodium falciparum in vitro. The phosphorothioated hammerhead ribozymes targeted unique regions of the P. falciparum carbamoyl-phosphate synthetase II gene. The P. falciparum carbamoyl-phosphate synthetase II gene encodes the first and limiting enzyme in the pathway, and its mRNA transcript contains two large insert regions absent in other carbamoyl-phosphate synthetases, including that from humans. These inserts are ideal targets for nucleic acid therapy. Exogenous delivery of ribozymes to cultures reduced malarial viability up to 55% at 0.5 microM ribozyme concentrations, which is significantly greater than control levels (5-15% reduction), suggesting a sequence-specific inhibition. This inhibition was shown to be stage-specific, with optimal inhibitions being detected after 24 h, coincident with maximal production of the carbamoyl-phosphate synthetase enzyme in the course of the life cycle of the parasite. A decrease in total carbamoyl-phosphate synthetase activity was observed only in cultures treated with the ribozymes. The task of developing alternative therapeutic agents against malaria is urgent due to the evolution of drug-resistant strains of P. falciparum, the most virulent of all human malarial parasites. Another critical issue to be addressed is the possibility of eliminating or reducing any systemic toxicity to the host, which can potentially be provided by nucleic acid therapy. This work is the first reported assessment of the ability of ribozymes as antimalarials. Ribozyme inhibition assays can also aid in identifying important antimalarial loci for chemotherapy. The malarial parasite can, in turn, be a useful in vivo host to study the catalysis and function of new ribozyme designs.
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Affiliation(s)
- M V Flores
- School of Biochemistry and Molecular Genetics, University of New South Wales, Sydney 2052, Australia.
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19
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Nambiar A, Kandala JC, Dolan SA, Jensen JB, Guntaka RV. Molecular cloning and characterization of a cDNA for the highly conserved HMG-like protein (Pf16) gene of Plasmodium falciparum. Biochem Biophys Res Commun 1997; 234:101-6. [PMID: 9168969 DOI: 10.1006/bbrc.1997.6584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A cDNA clone (PfHB3-2-4) of 1538 bp corresponding to the highly conserved HMG-like protein (Pf16) was isolated. However, northern analysis suggests that the mRNA is about 2.2 to 2.3 kb. Analysis by RT-PCR indicated that the 0.6 to 0.7 kb sequence missing in the cDNA maps to the 3' end, suggesting that the cDNA is terminated within the 26 adenosine residues that are in the middle of the Pf16 sequence. The most unique feature about this cDNA is the presence of two open reading frames (ORF), one from nucleotides 91 to 927 and the other starting from 1421. The second ORF corresponds to Pf16. Expression of the cDNA clones in Escherichia coli and translation in rabbit reticulocytes of RNA transcribed from the T7 promoter of the cDNA clones revealed that only the 3' end Pf16 is translated from this mRNA. Further experiments with antisense oligonucleotides specific for Pf16 indicated that the Pf16 protein serves an important function in the life cycle of the parasite.
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Affiliation(s)
- A Nambiar
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri-Columbia 65212, USA
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20
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Schrevel J. Antimalarial chemotherapy based on proteinase inhibitors. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 1997. [DOI: 10.1080/00034983.1997.11813246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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21
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Réfrégiers M, Laigle A, Jollès B, Chinsky L. Fluorescence resonance energy transfer analysis of the degradation of an oligonucleotide protected by a very stable hairpin. J Biomol Struct Dyn 1996; 14:365-71. [PMID: 9016413 DOI: 10.1080/07391102.1996.10508131] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In vitro degradation of antisense oligonucleotides protected or not on their 3' side against enzymatic attack by a naturally forming hairpin has been studied by fluorescence resonance energy transfer (FRET). The two oligonucleotides d(5"TTCTCGCGAAGC3') forming the hairpin and d(5"TTCTCCGGAAGC3') as a control were labeled on their 5' side by tetramethylrhodamine and on their 3' side by fluorescein. Fluorescein has been shown not to hinder the hairpin formation and to give an additional protection against nucleases. The FRET technique proved adequate for an in situ study of these protected antisense oligonucleotides in living cells.
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Affiliation(s)
- M Réfrégiers
- Laboratoire de Physicochimie Biomoléculaire et Cellulaire, URA CNRS 2056, Université, P. et M. Curie, Paris, France
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22
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Tovar J, Fairlamb AH. Extrachromosomal, homologous expression of trypanothione reductase and its complementary mRNA in Trypanosoma cruzi. Nucleic Acids Res 1996; 24:2942-9. [PMID: 8760878 PMCID: PMC146039 DOI: 10.1093/nar/24.15.2942] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Trypanothione reductase (TR), a flavoprotein oxidoreductase present in trypanosomatids but absent in human cells, is regarded as a potential target for the chemotherapy of several tropical parasitic diseases caused by trypanosomes and leishmanias. We investigated the possibility of modulating intracellular TR levels in Trypanosoma cruzi by generating transgenic lines that extrachromosomally overexpress either sense or antisense TR mRNA. Cells overexpressing the sense construct showed a 4-10-fold increase in levels of TR mRNA, protein and enzyme activity. In contrast, recombinant T.cruzi harbouring the antisense construct showed no significant difference in TR protein or catalytic activity when compared with control cells. Although increased levels of TR mRNA were detected in some of the antisense cells neither upregulation nor amplification of the endogenous trypanothione reductase gene (tryA) was observed. Instead, a proportion of plasmid molecules was found rearranged and, as a result, contained the tryA sequence in the sense orientation. Plasmid rescue experiments and sequence analysis of rearranged plasmids revealed that this specific gene inversion event was associated with the deletion of small regions of flanking DNA.
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Affiliation(s)
- J Tovar
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, UK
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23
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Barker RH, Metelev V, Rapaport E, Zamecnik P. Inhibition of Plasmodium falciparum malaria using antisense oligodeoxynucleotides. Proc Natl Acad Sci U S A 1996; 93:514-8. [PMID: 8552672 PMCID: PMC40268 DOI: 10.1073/pnas.93.1.514] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We studied inhibition of growth of the malaria parasite Plasmodium falciparum in in vitro culture using antisense (AS) oligodeoxynucleotides (ODNs) against different target genes. W2 and W2mef strains of drug-resistant parasites were exposed to AS ODNs over 48 hr, and growth was determined by microscopic examination and [3H]hypoxanthine incorporation. At ODN concentrations of 1 microM, phosphorothioate (PS) ODNs inhibited growth in a target-independent manner. However, between 0.5 and 0.005 microM, ODNs against dihydrofolate reductase, dihydropteroate synthetase, ribonucleotide reductase, the schizont multigene family, and erythrocyte binding antigen EBA175 significantly inhibited growth compared with a PS AS ODN against human immunodeficiency virus, two AS ODNs containing eight mismatches, or the sense strand controls (P < 0.0001). The IC50 was approximately 0.05 microM, whereas that for non-sequence-specific controls was 15-fold higher. PS AS ODNs against DNA polymerase alpha showed less activity than that for other targets, whereas a single AS ODN against triose-phosphate isomerase did not differ significantly from controls. We conclude that at concentrations below 0.5 microM, PS AS ODNs targeted against several malarial genes significantly inhibit growth of drug-resistant parasites in a nucleotide sequence-dependent manner. This technology represents an alternative method for identifying malarial genes as potential drug targets.
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Affiliation(s)
- R H Barker
- Hybridon, Inc., Worcester, MA 01605, USA
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24
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Tao LF, Marx KA, Wongwit W, Jiang Z, Agrawal S, Coleman RM. Uptake, intracellular distribution, and stability of oligodeoxynucleotide phosphorothioate by Schistosoma mansoni. ANTISENSE RESEARCH AND DEVELOPMENT 1995; 5:123-9. [PMID: 7580116 DOI: 10.1089/ard.1995.5.123] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The in vitro uptake, cellular distribution, efflux, stability, and toxicity levels of an oligodeoxynucleotide phosphorothioate (PS-oligonucleotide) have been studied in mature Schistosoma mansoni worms. The intracellular accumulation of 35S-labeled PS-oligonucleotide occurred roughly in proportion to the worm body mass over a wide concentration range, whether the worms were exposed singly or in mating pairs. Cellular uptake was dependent on the extracellular concentration. A minor fraction (13%) of the PS-oligonucleotide taken up by the worm accumulated in the surface tegumental coat. Most of the PS-oligonucleotide taken up localized in the cytosol (54%) and the nuclei-enriched (33%) fractions. In a time course study on adult worms in culture, oligonucleotide uptake was observed within the first 2 h and peaked at about 36 h. A decrease in the intracellular concentration of the PS-oligonucleotide was observed by 42 h. Analysis of the extracted oligonucleotides showed that PS-oligonucleotide was digested slowly. Efflux of the oligonucleotide was time and temperature dependent. Significant toxicity to the cultured worms did not occur until the PS-oligonucleotide concentration was over 8 mg/ml (1 mM).
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Affiliation(s)
- L F Tao
- Center for Tropical Diseases, University of Massachusetts-Lowell 01854, USA
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25
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Kim DY, Shih DS, Cho DY, Swenson DH. Helix-stabilizing compounds CC-1065 and U-71,184 bind to RNA-DNA and DNA-DNA duplexes containing modified internucleotide linkages and stabilize duplexes against thermal melting. ANTISENSE RESEARCH AND DEVELOPMENT 1995; 5:49-57. [PMID: 7542048 DOI: 10.1089/ard.1995.5.49] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
CC-1065 and U-71,184 bind and hyperstabilize DNA duplexes, but little is known about their effects on nucleic acid duplexes of different structure. A 20 mer DNA sequence (5'-TTACTTCAGTTATGAGACCA) containing a drug binding sequence (5'-AGTTA) was selected as the target sequence, and this was duplexed with complementary antisense sequences containing phosphodiester (PO), phosphorothioate (PS), and methylphosphonate (MP) bonds. The duplexes containing PO or PS bound 2 CC-1065 molecules per duplex, presumably at both the target site and at a lower affinity site (5'-AGTAA) on the antisense strand. The duplex containing MP bound only 1 CC-1065, and all duplexes bound only 1 U-71,184. Both CC-1065 and U-71,184 bound to 20 mer duplexes comprised of oligo(dA)-oligo(dT) (2.5 and 2 drugs per duplex, respectively) and poly(rA)-oligo(dT) (1 drug per 20 base pairs). CC-1065 also bound to duplexes between the PO- or PS-based antisense structures and a complementary synthetic 20 mer RNA sequence, with about 1 drug per duplex in each case. CC-1065 increased the Tm for the 20 mer DNA duplexes 17 to 29 degrees C, and the corresponding values for U-71,184 ranged from 7 to 19 degrees C. CC-1065 raised the Tm of oligo(dA)-oligo(dT) and poly(rA)-oligo(dT) 29 degrees C. U71,184 increased the Tm for oligo(dA)-oligo(dT) 30 degrees C but did not significantly elevate the Tm for the corresponding RNA-DNA duplex. The results show that CC-1065 and U-71,184 are capable of binding and stabilizing a variety of nucleic acid duplexes. These agents or their analogs may become useful ligands for antisense oligonucleotide applications.
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Affiliation(s)
- D Y Kim
- Department of Veterinary Pathology, School of Veterinary Medicine, Louisiana State University (LSU), Baton Rouge 70803, USA
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26
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27
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Metelev V, Lisziewicz J, Agrawal S. Study of antisense oligonucleotide phosphorothioates containing segments of oligodeoxynucleotides and 2′-o- methyloligoribonucleotides. Bioorg Med Chem Lett 1994. [DOI: 10.1016/s0960-894x(01)80842-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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28
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Leavitt MC, Yu M, Yamada O, Kraus G, Looney D, Poeschla E, Wong-Staal F. Transfer of an anti-HIV-1 ribozyme gene into primary human lymphocytes. Hum Gene Ther 1994; 5:1115-20. [PMID: 7833371 DOI: 10.1089/hum.1994.5.9-1115] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We reported previously that human CD4+ T cell lines stably expressing a hairpin ribozyme targeted to the human immunodeficiency virus type 1 (HIV-1) U5 leader sequence were resistant to challenge with diverse HIV-1 viral clones and clinical isolates (Yamada et al., 1994). To simulate more closely the in vivo infection process for investigations of anti-HIV-1 ribozyme gene therapy, we developed a system to transfer this ribozyme gene into freshly isolated human peripheral blood lymphocytes (PBLs) using a murine retrovirus vector. Following transduction and G418 selection, human PBLs from multiple donors expressed the ribozyme and resisted challenge by HIV-1 viral clones and clinical isolates, while control vector-transduced PBLs remained fully permissive for HIV-1 infection. No inhibition of an HIV-2 clone lacking the target was seen in ribozyme-expressing PBLs. Ribozyme expression had no effect on viability or proliferation kinetics of the primary lymphocytes. This study is the first demonstration in primary human T cells of resistance to HIV-1 infection conferred by gene transfer. A human clinical trial is in development to test further the safety and efficacy of this ribozyme in PBLs of HIV-1-infected patients in vivo.
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Affiliation(s)
- M C Leavitt
- Department of Medicine, University of California, San Diego, La Jolla 92093-0665
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29
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Ramazeilles C, Mishra RK, Moreau S, Pascolo E, Toulmé JJ. Antisense phosphorothioate oligonucleotides: selective killing of the intracellular parasite Leishmania amazonensis. Proc Natl Acad Sci U S A 1994; 91:7859-63. [PMID: 8058724 PMCID: PMC44503 DOI: 10.1073/pnas.91.17.7859] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We targeted the mini-exon sequence, present at the 5' end of every mRNA of the protozoan parasite Leishmania amazonensis, by phosphorothioate oligonucleotides. A complementary 16-mer (16PS) was able to kill amastigotes--the intracellular stage of the parasite--in murine macrophages in culture. After 24 hr of incubation with 10 microM 16PS, about 30% infected macrophages were cured. The oligomer 16PS acted through antisense hybridization in a sequence-dependent way; no effect on parasites was observed with noncomplementary phosphorothioate oligonucleotides. The antisense oligonucleotide 16PS was a selective killer of the protozoans without any detrimental effect to the host macrophage. Using 16PS linked to a palmitate chain, which enabled it to complex with low density lipoproteins, improved the leishmanicidal efficiency on intracellular amastigotes, probably due to increased endocytosis. Phosphorothioate oligonucleotides complementary to the intron part of the mini-exon pre-RNA were also effective, suggesting that antisense oligomers could prevent trans-splicing in these parasites.
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Affiliation(s)
- C Ramazeilles
- Laboratoire de Biophysique Moléculaire Institut National de la Santé et de la Recherche Médicale Unité 386, Université de Bordeaux II, France
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30
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Stec WJ, Wilk A. Stereokontrollierte Synthese von Oligonucleosidphosphorothioaten. Angew Chem Int Ed Engl 1994. [DOI: 10.1002/ange.19941060704] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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31
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Cohen JS. Gene-mimetic substances: drugs designed to intervene in gene expression. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 1994; 25:319-39. [PMID: 8204505 DOI: 10.1016/s1054-3589(08)60436-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- J S Cohen
- Cancer Pharmacology Section, Georgetown University Medical Center, Washington, D.C. 20007
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Galbraith WM, Hobson WC, Giclas PC, Schechter PJ, Agrawal S. Complement activation and hemodynamic changes following intravenous administration of phosphorothioate oligonucleotides in the monkey. ANTISENSE RESEARCH AND DEVELOPMENT 1994; 4:201-6. [PMID: 7849490 DOI: 10.1089/ard.1994.4.201] [Citation(s) in RCA: 165] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Rapid intravenous infusion of GEM 91, a 25-mer phosphorothioate oligonucleotide complementary to the gag site of HIV, in the monkey produces transient decreases in peripheral total WBC and neutrophil counts, hemoconcentration, and a brief increase followed by a prolonged decrease in arterial blood pressure. These changes are preceded by and are likely mediated by activation of C5 complement. These effects are dose and infusion rate dependent and can be avoided by administering GEM 91 by slow intravenous infusion. Similar hemodynamic effects are produced with rapid intravenous infusion of other phosphorothioate oligonucleotides varying in length from 20- to 33-mer, and are, therefore, not sequence specific but a property of this chemical structure.
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Chakrabarti D, Schuster SM, Chakrabarti R. Cloning and characterization of subunit genes of ribonucleotide reductase, a cell-cycle-regulated enzyme, from Plasmodium falciparum. Proc Natl Acad Sci U S A 1993; 90:12020-4. [PMID: 8265664 PMCID: PMC48117 DOI: 10.1073/pnas.90.24.12020] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Ribonucleotide reductase (EC 1.17.4.1; RNR), a cell-cycle-regulated enzyme, catalyzes the rate-limiting step in the de novo synthesis of deoxyribonucleotides by the reduction of the corresponding ribonucleotides. The important role of the RNR in DNA synthesis and cell division makes this enzyme an excellent target for chemotherapy. However, nothing is known about this enzyme from the malaria parasite Plasmodium falciparum. We have isolated cDNA clones encoding both the large and small RNR subunits. The sequences of full-length clones of the large and small RNR subunits revealed an open reading frame encoding 806 and 349 amino acids, respectively, and showed significant identity with other RNR sequences in the data base. RNA blot analysis showed that the size of the large and small RNR subunit transcripts are 5.4 kb and 2.2 kb, respectively. Both the RNR subunit transcripts fluctuate in level during the cell cycle, reaching a peak preceding maximal DNA synthesis activity. An oligodeoxynucleotide phosphorothioate that is complementary to sequences around the translational initiation codon of the small RNR subunit showed significant inhibition of growth, as measured by the inhibition in DNA synthesis.
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Affiliation(s)
- D Chakrabarti
- Department of Infectious Diseases, University of Florida, Gainesville 32611-0880
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Dominski Z, Kole R. Restoration of correct splicing in thalassemic pre-mRNA by antisense oligonucleotides. Proc Natl Acad Sci U S A 1993; 90:8673-7. [PMID: 8378346 PMCID: PMC47420 DOI: 10.1073/pnas.90.18.8673] [Citation(s) in RCA: 298] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Antisense 2'-O-methylribooligonucleotides were targeted against specific sequence elements in mutated human beta-globin pre-mRNAs to restore correct splicing of these RNAs in vitro. The following mutations of the beta-globin gene, A-->G at nt 110 of the first intron (beta 110), T-->G at nt 705 and C-->T at nt 654 of the second intron (IVS2(705) and IVS2(654), respectively), which led to aberrant splicing of the corresponding pre-mRNAs, were previously identified as the underlying causes of beta-thalassemia. Aberrant splicing of beta 110 pre-mRNA was efficiently reversed by an oligonucleotide targeted against the branch point sequence in the first intron of the pre-mRNA but not by an oligonucleotide targeted against the aberrant 3' splice site. In both IVS2(705) and IVS2(654) pre-mRNAs, correct splicing was restored by oligonucleotides targeted against the aberrant 5' splice sites created by the mutations in the second intron or against a cryptic 3' splice site located upstream and activated in the mutated background. These experiments represent an approach in which antisense oligonucleotides are used to restore the function of a defective gene and not, as usual, to down-regulate the expression of an undesirable gene.
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Affiliation(s)
- Z Dominski
- Department of Pharmacology, University of North Carolina, Chapel Hill 27599
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35
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Beaucage SL, Iyer RP. The synthesis of modified oligonucleotides by the phosphoramidite approach and their applications. Tetrahedron 1993. [DOI: 10.1016/s0040-4020(01)87958-8] [Citation(s) in RCA: 277] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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36
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Tang JY, Temsamani J, Agrawal S. Self-stabilized antisense oligodeoxynucleotide phosphorothioates: properties and anti-HIV activity. Nucleic Acids Res 1993; 21:2729-35. [PMID: 8392706 PMCID: PMC309610 DOI: 10.1093/nar/21.11.2729] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
A new class of oligodeoxyribonucleotides has been designed, referred to here as 'self-stabilized' oligonucleotides. These oligonucleotides have hairpin loop structures at their 3' ends, and show increased resistance to degradation by snake venom phosphodiesterase, DNA polymerase I and fetal bovine serum. The self-stabilized region of the oligonucleotide does not interfere in hybridization with complementary nucleic acids as shown by melting temperature, mobility-shift and RNase H cleavage studies. Various self-stabilized oligonucleotides containing increasingly stable hairpin loop regions were studied for their anti-HIV activity. Pharmacokinetic and stability studies in mice showed increased in vivo persistence of self-stabilized oligonucleotides with respect to their linear counterparts.
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Affiliation(s)
- J Y Tang
- Hybridon, Inc., Worcester, MA 01605
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37
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Gaudette MF, Hampikian G, Metelev V, Agrawal S, Crain WR. Effect on embryos of injection of phosphorothioate-modified oligonucleotides into pregnant mice. ANTISENSE RESEARCH AND DEVELOPMENT 1993; 3:391-7. [PMID: 8155980 DOI: 10.1089/ard.1993.3.391] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Phosphorothioate-modified oligonucleotides were injected into pregnant female mice to assess the effect on developing embryos. Injections were carried out during two different time periods, one when embryos were in preimplantation stages of development (about 3.5 days of development) and the other after implantation, when both a fetus and placenta are present (from days 9.5 to 11.5 of development). Three different phosphorothioate-modified oligonucleotides were injected. One, which had a sequence not present in the mouse genome, was used to ask whether nonspecific toxic or teratogenic effects on embryos result from treatment of the mother. A second was complementary to the mRNA of the testis-determining factor gene Sry and was used to ask whether a specific developmental pathway (i.e., sex determination) could be disrupted in embryos in vivo. The third was the complement of the anti-Sry sequence. None of these oligonucleotides reduced the frequency of successful pregnancy after mating or the average litter size from that observed in controls animals. Furthermore, examination of 291 pups or fetuses from all oligonucleotide-injected pregnant females revealed no developmental defects regardless of which sequence was used. It is concluded that injection of phosphorothioate-modified oligonucleotides into pregnant females according to the protocols described here is not toxic or teratogenic to embryos in a nonspecific way. Also, anti-Sry oligonucleotides did not influence sex determination in embryos, although there are several possible explanations for this.
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Affiliation(s)
- M F Gaudette
- Cell Biology Group, Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts 01545
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38
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An indexed bibliography of antisense literature, 1992. ANTISENSE RESEARCH AND DEVELOPMENT 1993; 3:95-153. [PMID: 8495109 DOI: 10.1089/ard.1993.3.95] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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