Potential conflict of interest: Nothing to report.
Efficacy of systemic morpholino exon-skipping in duchenne dystrophy dogs†
Article first published online: 13 MAR 2009
Copyright © 2009 American Neurological Association
Annals of Neurology
Volume 65, Issue 6, pages 667–676, June 2009
How to Cite
Yokota, T., Lu, Q.-l., Partridge, T., Kobayashi, M., Nakamura, A., Takeda, S. and Hoffman, E. (2009), Efficacy of systemic morpholino exon-skipping in duchenne dystrophy dogs. Ann Neurol., 65: 667–676. doi: 10.1002/ana.21627
- Issue published online: 25 JUN 2009
- Article first published online: 13 MAR 2009
- Manuscript Accepted: 5 DEC 2008
- Manuscript Revised: 29 NOV 2008
- Manuscript Received: 1 JUL 2008
- Foundation to Eradicate Duchenne
- Department of Defense CDMRP program. Grant Number: W81XWH-05-1-0616
- Jain Foundation
- Crystal Ball of Virginia Beach (Muscular Dystrophy Association USA)
- National Center for Medical Rehabilitation Research. Grant Number: 5R24HD050846-02
- NIH Wellstone Muscular Dystrophy Research Centers. Grant Number: IU54HD053177-01A1
- Ministry of Health, Labor, and Welfare of Japan (Research on Nervous and Mental Disorders). Grant Numbers: 16B-2, 19A-7
- Ministry of Health, Labor, and Welfare of Japan (Health and Labor Sciences, Research Grants for Translation Research; Health Sciences Research Grants for Research on Psychiatry and Neurological Disease and Mental Health). Grant Numbers: H19-translational research-003, H18-kokoro-019
Duchenne muscular dystrophy (DMD) is caused by the inability to produce dystrophin protein at the myofiber membrane. A method to rescue dystrophin production by antisense oligonucleotides, termed exon-skipping, has been reported for the mdx mouse and in four DMD patients by local intramuscular injection. We sought to test efficacy and toxicity of intravenous oligonucleotide (morpholino)-induced exon skipping in the DMD dog model.
We tested a series of antisense drugs singly and as cocktails, both in primary cell culture, and two in vivo delivery methods (intramuscular injection and systemic intravenous injection). The efficiency and efficacy of multiexon skipping (exons 6–9) were tested at the messenger RNA, protein, histological, and clinical levels.
Weekly or biweekly systemic intravenous injections with a three-morpholino cocktail over the course of 5 to 22 weeks induced therapeutic levels of dystrophin expression throughout the body, with an average of about 26% normal levels. This was accompanied by reduced inflammatory signals examined by magnetic resonance imaging and histology, improved or stabilized timed running tests, and clinical symptoms. Blood tests indicated no evidence of toxicity.
This is the first report of widespread rescue of dystrophin expression to therapeutic levels in the dog model of DMD. This study also provides a proof of concept for systemic multiexon-skipping therapy. Use of cocktails of morpholino, as shown here, allows broader application of this approach to a greater proportion of DMD patients (90%) and also offers the prospect of selecting deletions that optimize the functionality of the dystrophin protein. Ann Neurol 2009