In vivo comparison of 2′-O-methyl phosphorothioate and morpholino antisense oligonucleotides for Duchenne muscular dystrophy exon skipping
Article first published online: 12 JAN 2009
Copyright © 2009 John Wiley & Sons, Ltd.
The Journal of Gene Medicine
Volume 11, Issue 3, pages 257–266, March 2009
How to Cite
Heemskerk, H. A., de Winter, C. L., de Kimpe, S. J., van Kuik-Romeijn, P., Heuvelmans, N., Platenburg, G. J., van Ommen, G.-J. B., van Deutekom, J. C. T. and Aartsma-Rus, A. (2009), In vivo comparison of 2′-O-methyl phosphorothioate and morpholino antisense oligonucleotides for Duchenne muscular dystrophy exon skipping. J. Gene Med., 11: 257–266. doi: 10.1002/jgm.1288
- Issue published online: 19 FEB 2009
- Article first published online: 12 JAN 2009
- Manuscript Accepted: 19 NOV 2008
- Manuscript Revised: 5 NOV 2008
- Manuscript Received: 7 AUG 2008
- Dutch Duchenne Parent Project
- Center for Biomedical Genetics
- antisense oligonucleotides;
- Duchenne muscular dystrophy;
- exon skipping;
- 2′-O-methyl phosphorothioate;
- phosphorodiamidate morpholino oligomer
Antisense-mediated exon skipping is a putative treatment for Duchenne muscular dystrophy (DMD). Using antisense oligonucleotides (AONs), the disrupted DMD reading frame is restored, allowing generation of partially functional dystrophin and conversion of a severe Duchenne into a milder Becker muscular dystrophy phenotype. In vivo studies are mainly performed using 2′-O-methyl phosphorothioate (2OMePS) or morpholino (PMO) AONs. These compounds were never directly compared.
mdx and humanized (h)DMD mice were injected intramuscularly and intravenously with short versus long 2OMePS and PMO for mouse exon 23 and human exons 44, 45, 46 and 51.
Intramuscular injection showed that increasing the length of 2OMePS AONs enhanced skipping efficiencies of human exon 45, but decreased efficiency for mouse exon 23. Although PMO induced more mouse exon 23 skipping, PMO and 2OMePS were more comparable for human exons. After intravenous administration, exon skipping and novel protein was shown in the heart with both chemistries. Furthermore, PMO showed lower intramuscular concentrations with higher exon 23 skipping levels compared to 2OMePS, which may be due to sequestration in the extracellular matrix. Finally, two mismatches rendered 2OMePS but not PMO AONs nearly ineffective.
The results obtained in the present study indicate that increasing AON length improves skipping efficiency in some but not all cases. It is feasible to induce exon skipping and dystrophin restoration in the heart after injection of 2OMePS and unconjugated PMO. Furthermore, differences in efficiency between PMO and 2OMePS appear to be sequence and not chemistry dependent. Finally, the results indicate that PMOs may be less sequence specific than 2OMePS. Copyright © 2009 John Wiley & Sons, Ltd.