Restoration of correct splicing in IVSI-110 mutation of β-globin gene with antisense oligonucleotides: implications and applications in functional assay development

Document Type : Original Article

Authors

Department of Medical Genetics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran

Abstract

Objective(s): The use of antisense oligonucleotides (AOs) to restore normal splicing by blocking the recognition of aberrant splice sites by the spliceosome represents an innovative means of potentially controlling certain inherited disorders affected by aberrant splicing. Selection of the appropriate target site is essential in the success of an AO therapy. In this study, in search for a splice model system to facilitate the evaluation of AOs to redirect defective splicing of IVSI-110 β-globin intron, an EGFP-based IVSI-110 specific cellular reporter assay system has been developed and a number of AOs were tested in this cellular splicing assay.
Materials and Methods: A recombinant plasmid (pEGFP/I-110) carrying the EGFP gene interrupted by a mutated human β-globin intron 1 (IVSI-110) was developed and transfected into K562 cells. A number of AOs with a 2’-O-methyl oligoribonucleotide (2’-O-Me) backbone system were systematically tested in this cellular splicing assay.
Results: The mutation in the intron causes aberrant splicing of EGFP pre-mRNA, preventing translation of EGFP; however, treatment of the cells with specific concentration of a sequence specific 2’-O-Me AO targeted to the aberrant splice site induced correct splicing and resulted in restoring of EGFP activity.
Conclusion: This cellular splicing assay provides a novel functional assay system in assessing the cellular delivery efficiency of AOs and therapeutic effect of AOs in restoration of aberrant splicing.

Keywords


1. Wilton SD, Fall AM, Harding PL, McClorey G, Coleman C, Fletcher S. Antisense oligonucleotide-induced exon skipping across the human dystrophin gene transcript. Mol Ther J Am Soc Gene Ther 2007; 15:1288-1296.
2. Sazani P, Astriab-Fischer A, Kole R. Effects of base modifications on antisense properties of 2'-O-methoxyethyl and PNA oligonucleotides. Antisense Nucleic Acid Drug Dev 2003c; 13:119-128.
3. Kole R, Krainer AR, Altman S. RNA therapeutics: beyond RNA interference and antisense oligonucleo-tides. Nat Rev Drug Discov 2012; 11:125-140.
4. Andronescu M, Zhang ZC, Condon A. Secondary structure prediction of interacting RNA molecules. J Mol Biol 2005; 345:987-1001.
5. Sazani P, Kang SH, Maier MA, Wei C, Dillman J, Summerton J, et al. Nuclear antisense effects of neutral, anionic and cationic oligonucleotide analogs. Nucleic Acids Res 2001; 29:3965-3974.
6. Sazani P, Gemignani F, Kang SH, Maier MA, Manoharan M, Persmark M, et al. Systemically delivered antisense oligomers upregulate gene expression in mouse tissues. Nat Biotechnol 2002; 20:1228-1233.
7. Vadolas J, Nefedov M, Wardan H, Mansoori-derakshan S, Voullaire L, Jamsai D, et al. Humanized beta-thalassemia mouse model containing the common IVSI-110 splicing mutation. J Biol Chem 2006; 281:7399-7405.
8. Spritz RA, Jagadeeswaran P, Choudary PV, Biro PA, Elder JT, deRiel JK, et al. Base substitution in an intervening sequence of a beta+-thalassemic human globin gene. Proc Natl Acad Sci U S A 1981; 78:2455-249.
9. Popplewell LJ, Trollet C, Dickson G, Graham IR. Design of phosphorodiamidate morpholino oligomers (PMOs) for the induction of exon skipping of the human DMD gene. Mol Ther 2009; 17:554-561.
10. Majlessi M, Nelson NC, Becker MM. Advantages of 2'-O-methyl oligoribonucleotide probes for detecting RNA targets. Nucleic Acids Res 1998 ; 26:2224-2229.
11. Lamm GM, Blencowe BJ, Sproat BS, Iribarren AM, Ryder U, Lamond AI. Antisense probes containing 2-aminoadenosine allow efficient depletion of U5 snRNP from HeLa splicing extracts. Nucleic Acids Res 1991; 19:3193-3198.
12. Bharti Bhandari DC, Neeta Wardhan. Antisense oligonucleotide: basic concept and its therapeutic application. J Res Pharm Sci 2014; 2:01-13.
13. Dominski Z, Kole R. Restoration of correct splicing in thalassemic pre-mRNA by antisense oligonucleo-tides. Proc Natl Acad Sci U S A 1993; 90:8673-8677.
14. Kang SH, Cho MJ, Kole R. Up-regulation of luciferase gene expression with antisense oligonucleotides: implications and applications in functional assay development. Biochemistry 1998; 37:6235-6239.
15. El-Beshlawy A, Mostafa A, Youssry I, Gabr H, Mansour IM, El-Tablawy M, et al. Correction of aberrant pre-mRNA splicing by antisense oligonucleotides in beta-thalassemia Egyptian patients with IVSI-110 mutation. J Pediatr Hematol Oncol 2008 ; 30:281-284.
16. Suwanmanee T, Sierakowska H, Lacerra G, Svasti S, Kirby S, Walsh CE, et al. Restoration of human beta-globin gene expression in murine and human IVS2-654 thalassemic erythroid cells by free uptake of antisense oligonucleotides. Mol Pharmacol 2002; 62:545-553.
17. Lacerra G, Sierakowska H, Carestia C, Fucharoen S, Summerton J, Weller D, et al. Restoration of hemoglobin A synthesis in erythroid cells from peripheral blood of thalassemic patients. Proc Natl Acad Sci U S A 2000; 97:9591-9596.