Submitted on December 14, 2001
Accepted on December 18, 2002
Transfection of lung cells in vitro and in vivo: effect of antioxidants and intraliposomal bFGF
Xiaoping Luo1, Rosetta Belcastro2, Judy Cabacungan2, Vicky Hannam3, Anna Negus3, Yanxia Wen3, Jonathan Plumb3, Jim Hu2, Brent Steer3, David R. Koehler4, Gregory P. Downey5, and A. Keith Tanswell6*
1 Department of Pediatrics, Tonji Medical College, Huazhong University of Science and Technology, Tonji, Wuhan, China
2 The Canadian Institutes for Health Research in Lung Development, Toronto, Ontario, Canada; Lung Biology Programme, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
3 Lung Biology Programme, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
4 The Canadian Institutes for Health Research in Lung Development, Toronto, Ontario, Canada
5 Lung Biology Programme, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada; Department of Medicine, University of Toronto, Toronto, Ontario, Canada; Department of Physiology, University of Toronto, Toronto, Ontario, Canada
6 The Canadian Institutes for Health Research in Lung Development, Toronto, Ontario, Canada; Lung Biology Programme, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada; Department of Physiology, University of Toronto, Toronto, Ontario, Canada
* To whom correspondence should be addressed. E-mail: keith.tanswell{at}sickkids.ca.
We hypothesized that constitutive formation of reactive oxygen species by respiratory cells is a barrier to gene transfer, when using liposome:DNA complexes, by contributing to rapid degradation of plasmid DNA. When plasmid DNA is complexed to liposomes it is protected against H2O2-mediated degradation, but not that mediated by the hydroxyl radical. Treatment of distal rat fetal lung epithelial cells (RFL19Ep) with the vitamin E analogue, Trolox (50 µM) reduced intracellular plasmid degradation. Both Trolox (50 µM) and an iron chelator, phenanthroline (0.1 µM), significantly increased transgene expression in RFL19Ep 
2-fold, consistent with a hydroxyl radical-mediated inhibition of transgene expression. When bFGF (20 ng/ml), a growth factor with antioxidant properties, was included within liposomes a significantly greater enhancement of RFL19Ep transgene expression ( 2-fold), over that seen with Trolox or phenanthroline, was observed. Inclusion of bFGF within liposomes also significantly enhanced ( 4-fold) transgene expression in mice following intratracheal instillation.
