Targeted Activation of Cystic Fibrosis Transmembrane Conductance Regulator

Mol Ther. 2019 Oct 2;27(10):1737-1748. doi: 10.1016/j.ymthe.2019.07.002. Epub 2019 Jul 15.


Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. The majority of CFTR mutations result in impaired chloride channel function as only a fraction of the mutated CFTR reaches the plasma membrane. The development of a therapeutic approach that facilitates increased cell-surface expression of CFTR could prove clinically relevant. Here, we evaluate and contrast two molecular approaches to activate CFTR expression. We find that an RNA-guided nuclease null Cas9 (dCas9) fused with a tripartite activator, VP64-p65-Rta can activate endogenous CFTR in cultured human nasal epithelial cells from CF patients. We also find that targeting BGas, a long non-coding RNA involved in transcriptionally modulating CFTR expression with a gapmer, induced both strong knockdown of BGas and concordant activation of CFTR. Notably, the gapmer can be delivered to target cells when generated as electrostatic particles with recombinant HIV-Tat cell penetrating peptide (CPP), when packaged into exosomes, or when loaded into lipid nanoparticles (LNPs). Treatment of patient-derived human nasal epithelial cells containing F508del with gapmer-CPP, gapmer-exosomes, or LNPs resulted in increased expression and function of CFTR. Collectively, these observations suggest that CRISPR/dCas-VPR (CRISPR) and BGas-gapmer approaches can target and specifically activate CFTR.

Keywords: ASO delivery; CFTR; Tat-CPP; cystic fibrosis; exosome; lncRNA BGas; transcriptional regulation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • CRISPR-Associated Protein 9 / metabolism
  • Cell Line
  • Cell Membrane / metabolism
  • Cell-Penetrating Peptides / genetics
  • Cystic Fibrosis / genetics*
  • Cystic Fibrosis / metabolism
  • Cystic Fibrosis / therapy
  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics*
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism*
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism
  • Humans
  • Molecular Targeted Therapy / methods*
  • Nanoparticles / chemistry
  • Nasal Mucosa / cytology
  • Nasal Mucosa / metabolism*
  • RNA, Guide, CRISPR-Cas Systems / pharmacology
  • RNA, Long Noncoding / genetics
  • Transcriptional Activation
  • tat Gene Products, Human Immunodeficiency Virus / genetics


  • CFTR protein, human
  • Cell-Penetrating Peptides
  • RNA, Guide, CRISPR-Cas Systems
  • RNA, Long Noncoding
  • tat Gene Products, Human Immunodeficiency Virus
  • Cystic Fibrosis Transmembrane Conductance Regulator
  • CRISPR-Associated Protein 9