The mucus barrier to inhaled gene therapy

Gregg A. Duncan, James Jung, Justin Hanes, Jung Soo Suk

Research output: Contribution to journalReview articlepeer-review

58 Scopus citations


Recent evidence suggests that the airway mucus gel layer may be impermeable to the viral and synthetic gene vectors used in past inhaled gene therapy clinical trials for diseases like cystic fibrosis. These findings support the logic that inhaled gene vectors that are incapable of penetrating the mucus barrier are unlikely to provide meaningful benefit to patients. In this review, we discuss the biochemical and biophysical features of mucus that contribute its barrier function, and how these barrier properties may be reinforced in patients with lung disease. We next review biophysical techniques used to assess the potential ability of gene vectors to penetrate airway mucus. Finally, we provide new data suggesting that fresh human airway mucus should be used to test the penetration rates of gene vectors. The physiological barrier properties of spontaneously expectorated CF sputum remained intact up to 24 hours after collection when refrigerated at 4 °C. Conversely, the barrier properties were significantly altered after freezing and thawing of sputum samples. Gene vectors capable of overcoming the airway mucus barrier hold promise as a means to provide the widespread gene transfer throughout the airway epithelium required to achieve meaningful patient outcomes in inhaled gene therapy clinical trials.

Original languageEnglish (US)
Pages (from-to)2043-2053
Number of pages11
JournalMolecular Therapy
Issue number12
StatePublished - Dec 1 2016

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology
  • Genetics
  • Pharmacology
  • Drug Discovery


Dive into the research topics of 'The mucus barrier to inhaled gene therapy'. Together they form a unique fingerprint.

Cite this