Approach to CFTR Editing in Differentiated Airway Epithelial Cells

P.I.: Richard James, PhD
Assistant Professor,
Pediatrics

Jason Debley, MD, MPH
Associate Professor,
Pediatrics

Cystic Fibrosis is autosomal recessive disorder driven by point mutations in CFTR on both copies of chromosome 7 that lead to defects in CFTR channel function (some protein processing, gating and conductance mutations) or defects in expression on the cell surface (protein production, insufficient protein and some protein processing mutations). These CFTR mutations can cause complete loss of protein function or partial loss of protein function (~0-25% residual function). As evidenced by the efficacy of CFTR modulators, which can double or triple CFTR protein function, partial rescue, even at low levels, is likely to provide clinical benefit. We hypothesize that gene editing could be used to directly repair these mutations at the level of the genome and partially rescue CFTR function in primary lung epithelia. The purpose of this proposal is to address the feasibility of using gene editing to repair CFTR mutations at the level of the genome. We will develop methods to directly repair all possible mutations in CFTR that are observed in Cystic Fibrosis and assess the percentages of cells that can be repaired using this method. We will also answer the question of how much repair is necessary to provide functional rescue of chloride channel function in gene-edited differented bronchial epithelial cells; in other words, what percentage of cells need to be repaired to restore CFTR function and chloride transport. We expect these feasibility studies to provide a path forward for evaluation of gene editing or alternative gene delivery methods for the treatment of Cystic Fibrosis.