Targeted gene correction of α(1)-antitrypsin deficiency in induced pluripotent stem cells

Human induced pluripotent stem cells (hIPSCs) represent a unique opportunity for regenerative medicine since they offer the prospect of generating unlimited quantities of cells for autologous transplantation as a novel treatment for a broad range of disorders(1,2,3,4). However, the use of hIPSCs in the context of genetically inherited human disease will require correction of disease-causing mutations in a manner that is fully compatible with clinical applications(3,5). The methods currently available, such as homologous recombination, lack the necessary efficiency and also leave residual sequences in the targeted genome(6). Therefore, the development of new approaches to edit the mammalian genome is a prerequisite to delivering the clinical promise of hIPSCs. Here, we show that a combination of zinc finger nucleases (ZFNs)(7) and piggyBac(8,9) technology in hIPSCs can achieve bi-allelic correction of a point mutation (Glu342Lys) in the α(1)-antitrypsin (A1AT, also called SERPINA1) gene that is responsible for α(1)-antitrypsin deficiency (A1ATD). Genetic correction of hIPSCs restored the structure and function of A1AT in subsequently derived liver cells in vitro and in vivo. This approach is significantly more efficient than any other gene targeting technology that is currently available and crucially prevents contamination of the host genome with residual non-human sequences. Our results provide the first proof of principle for the potential of combining hIPSCs with genetic correction to generate clinically relevant cells for autologous cell-based therapies.