title: Electroporation Enhanced Effect of Dystrophin Splice Switching PNA Oligomers in Normal and Dystrophic Muscle.
abstract: Peptide nucleic acid (PNA) is a synthetic DNA mimic that has shown potential for discovery of novel splice switching antisense drugs. However, in vivo cellular delivery has been a limiting factor for development, and only few successful studies have been reported. As a possible modality for improvement of in vivo cellular availability, we have investigated the effect of electrotransfer upon intramuscular (i.m.) PNA administration in vivo. Antisense PNA targeting exon 23 of the murine dystrophin gene was administered by i.m. injection to the tibialis anterior (TA) muscle of normal NMRI and dystrophic mdx mice with or without electroporation. At low, single PNA doses (1.5, 3, or 10 µg/TA), electroporation augmented the antisense exon skipping induced by an unmodified PNA by twofold to fourfold in healthy mouse muscle with optimized electric parameters, measured after 7 days. The PNA splice switching was detected at the RNA level up to 4 weeks after a single-dose treatment. In dystrophic muscles of the MDX mouse, electroporation increased the number of dystrophin-positive fibers about 2.5-fold at 2 weeks after a single PNA administration compared to injection only. In conclusion, we find that electroporation can enhance PNA antisense effects in muscle tissue.
authors.affiliation: Center for Experimental Drug and Gene Electrotransfer (CEDGE), Department of Oncology, Copenhagen University Hospital Herlev, Denmark.|Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Denmark.
authors.forename: Camilla
authors.initials: C
authors.lastname: Brolin
authors.affiliation: Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Denmark.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Shiraishi
authors.affiliation: The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, Denmark.
authors.forename: Pernille
authors.initials: P
authors.lastname: Hojman
authors.affiliation: Neuromuscular Research Unit, Department of Neurology Rigshospitalet, University of Copenhagen, Denmark.
authors.forename: Thomas O
authors.initials: TO
authors.lastname: Krag
authors.affiliation: Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Denmark.|Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Denmark.
authors.forename: Peter E
authors.initials: PE
authors.lastname: Nielsen
authors.affiliation: Center for Experimental Drug and Gene Electrotransfer (CEDGE), Department of Oncology, Copenhagen University Hospital Herlev, Denmark.
authors.forename: Julie
authors.initials: J
authors.lastname: Gehl