A gene therapy approach to cystic fibrosis

CF is a hereditary disease resulting from mutations in the cystic fibrosis transmembrane conductase regulator (CFTR) gene. CFTR is a membrane protein that regulates the flow of water and chloride ions. With first manifestations in early childhood, CF affects the lungs and later extends to other organs. Identification of the gene responsible for CF offers a possibility to develop an effective gene therapy protocol for this life-threatening disease. While many mutations in the CFTR gene can contribute to the disease, F508 mutation is responsible for over 70 % of CF cases in the European population.

The project GOODCELLS produced impressive results. The project had an ambitious goal to develop an approach for an efficient therapy for CF using genetically modified induced pluripotent stem (iPS) cells. iPS cells can be generated in vitro directly from adult cells of an individual and thus are patient-specific. Because iPS cells can give rise to every other cell in the body, they have a great potential for regenerative medicine.

During the GOODCELLS project the iPS cells were successfully produced from the cells of F508 CF patients and F508 mutant mice. Next, F508 mutation in the CFTR gene was corrected in the iPS cells using homologous recombination and piggyback technology. A corrected CFTR allele was validated by polymerase chain reaction and sequencing.

After repaired iPS cell lines were characterised, an in vitro differentiation protocol was established. The protocol mimicked the natural process of lung embryonic development and produced foregut endodermal mouse and human cells.

Finally, a series of cell transplantation experiments were performed on mice to define the conditions required for lung regeneration. Differentiated mouse cells carrying the corrected CFTR gene were intravenously injected into F508 mice and showed a clear tendency to home in on the lungs.

The project's results have important scientific implications. In addition to addressing CF therapy, the approach can be applied to other hereditary diseases.