1. ¹Department of Gene Therapy, Faculty of Medicine, Imperial College, London, UK
2. ²Center for Pharmacogenetics, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, USA
3. ³Division of Drug Delivery and Disposition, School of Pharmacy, University of North Carolina, Chapel Hill, NC, USA
4. ⁴Department of Thoracic Medicine, Faculty of Medicine, Imperial College, London, UK
5. ⁵UK Cystic Fibrosis Gene Therapy Consortium, UK

Correspondence: Dr U Griesenbach, Department of Gene Therapy, Faculty of Medicine, Imperial College, Emmanuel Kaye Building, NHLI, Manresa Road, London SW3 6LR, UK. E-mail: u.griesenbach@imperial.ac.uk

Received 13 October 2005; Revised 6 May 2006; Accepted 8 May 2006; Published online 22 June 2006.

Abstract

Topical gene transfer to the airways of cystic fibrosis (CF) patients has been inefficient, partly due to extracellular barriers such as sputum. In an attempt to circumvent these, we assessed whether airway epithelial cells can be transfected by intravenous (i.v.) administration of liposome-complexed or 'naked' oligonucleotides (ODNs). The conducting airways are the likely target for CF therapy and are supplied by the bronchial circulation. Consequently, we assessed ODN transfer in the mouse trachea and main bronchi as these are supplied by the bronchial circulation. Liposome–protamine–DNA (LPD) complexes were detected in the bronchial circulation but did not transfect conducting airway epithelial cells, even in the presence of microvascular leakage. In contrast, 'naked' ODNs were delivered to 17% (inter-quartile range (IQR) 10–34%) and 35% (IQR 24–59%) of epithelial cells when injected at 500 g/animal, without and with microvascular leakage, respectively. Two types of nuclear signal were observed; punctate in cells throughout the airways (3%, IQR 2–6%, and 6%, IQR 4–7%, of cells when delivered without and with microvascular leakage, respectively) and diffuse in a small number of epithelial cells in the proximal trachea. ODNs may be relevant to CF in a variety of ways and these data suggest one way towards implementing their use.