The effect of mucolytic agents on gene transfer across a CF sputum barrier in vitro

M. Stern, N. J. Caplen, J. E. Browning, U. Griesenbach, F. Sorgi, L. Huang, D. C. Gruenert, C. Marriot, R. G. Crystal, D. M. Geddes, E. W.F.W. Alton

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Trials of gene transfer for cystic fibrosis (CF) are currently underway. However, direct application to the airways may be impeded by the presence of airway secretions. We have therefore assessed the effect of CF sputum on the expression of the reporter gene β-galactosidase complexed with the cationic liposome DC-Chol/DOPE in a number of cell lines in vitro. Transfection was markedly inhibited in the presence of sputum; the effect was concentration dependent and was only partially ameliorated by removal of sputum with phosphate-buffered saline (PBS) washing before gene transfer. However, treatment of the sputum-covered cells with recombinant human DNase (rhDNase, 50 μg/ml). but not with N-acetylcysteine, Nacystelyn, lysine (all 20 mM) or recombinant alginase (0.5 U/ml) significantly (P < 0.005) improved gene transfer Adenovirus-mediated gene transfer efficiency in the presence of sputum was similarly inhibited, and again, treatment with rhDNase before transfection significantly improved gene transfer (P < 0.005). Transfection of Cos 7 cells in the presence of exogenous genomic DNA alone demonstrated similar inhibition to that observed with sputum and was also ameliorated by pre-treatment of DNA-covered cells with rhDNase. In a separate series of experiments performed in the absence of added sputum or genomic DNA, increasing concentrations of rhDNase resulted in a concentration-related decline in transfection efficiency. However, even at the highest concentration (500 μg/ml of rhDNase), transfection efficiency remained more than 50% of control. Thus, pre-treatment of CF airways with rhDNase may be appropriate before liposome or adenovirus-mediated gene therapy.

Original languageEnglish
Pages (from-to)91-98
Number of pages8
JournalGene Therapy
Issue number1
Publication statusPublished - 1 Jan 1998



  • Cystic fibrosis
  • Gene therapy
  • Sputum
  • rhDNase

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology
  • Genetics

Cite this

Stern, M., Caplen, N. J., Browning, J. E., Griesenbach, U., Sorgi, F., Huang, L., Gruenert, D. C., Marriot, C., Crystal, R. G., Geddes, D. M., & Alton, E. W. F. W. (1998). The effect of mucolytic agents on gene transfer across a CF sputum barrier in vitro. Gene Therapy, 5(1), 91-98.