Integration-free technologies with high reprogramming efficiency are key to the use of induced pluripotent stem cells and their derivatives in cell therapy and drug discovery applications. Sendai virus (SeV) has been used to reprogram somatic cells with high efficiency however, while recombinant SeV vectors only replicate in the cytoplasm of infected cells, continued cytoplasmic replication after reprogramming could prevent the use of SeV in therapeutic applications. Ban et al. present the use of temperature sensitive SeV vectors to generate viral and reprogramming factor free iPSCs from human fibroblasts and CD34+ cord blood cells at high efficiency.
Two recent papers report successful and consistent gene targeting in ESC and iPSC. The methods described overcome the current issue of exogeneous DNA introduced in gene therapy. This progresses field a step closer to therapeutic use of functional cells derived from ex-vivo repaired ES and iPS cells.
This study by Sue Lindquist's lab uses ZFN (Zinc finger nucleases) to insert or remove single base pair mutations in the aplha synucelin gene known to cause early onset Parkinson's disease. This allows generation of isogeneic control and disease iPSC lines that serves as a better model of disease in a dish.
The second study by Rudolf Jaenisch's lab, relies on TALENs (Transcription activator like effector nucleases) to alter genes with an efficiency and precision similar to ZFN.