• Generation of healthy mice from gene-corrected disease-specific induced pluripotent stem cells.

      Wu, Guangming; Liu, Na; Rittelmeyer, Ina; Sharma, Amar Deep; Sgodda, Malte; Zaehres, Holm; Bleidissel, Martina; Greber, Boris; Gentile, Luca; Han, Dong Wook; et al. (2011-07)
      Using the murine model of tyrosinemia type 1 (fumarylacetoacetate hydrolase [FAH] deficiency; FAH⁻/⁻ mice) as a paradigm for orphan disorders, such as hereditary metabolic liver diseases, we evaluated fibroblast-derived FAH⁻/⁻-induced pluripotent stem cells (iPS cells) as targets for gene correction in combination with the tetraploid embryo complementation method. First, after characterizing the FAH⁻/⁻ iPS cell lines, we aggregated FAH⁻/⁻-iPS cells with tetraploid embryos and obtained entirely FAH⁻/⁻-iPS cell-derived mice that were viable and exhibited the phenotype of the founding FAH⁻/⁻ mice. Then, we transduced FAH cDNA into the FAH⁻/⁻-iPS cells using a third-generation lentiviral vector to generate gene-corrected iPS cells. We could not detect any chromosomal alterations in these cells by high-resolution array CGH analysis, and after their aggregation with tetraploid embryos, we obtained fully iPS cell-derived healthy mice with an astonishing high efficiency for full-term development of up to 63.3%. The gene correction was validated functionally by the long-term survival and expansion of FAH-positive cells of these mice after withdrawal of the rescuing drug NTBC (2-(2-nitro-4-fluoromethylbenzoyl)-1,3-cyclohexanedione). Furthermore, our results demonstrate that both a liver-specific promoter (transthyretin, TTR)-driven FAH transgene and a strong viral promoter (from spleen focus-forming virus, SFFV)-driven FAH transgene rescued the FAH-deficiency phenotypes in the mice derived from the respective gene-corrected iPS cells. In conclusion, our data demonstrate that a lentiviral gene repair strategy does not abrogate the full pluripotent potential of fibroblast-derived iPS cells, and genetic manipulation of iPS cells in combination with tetraploid embryo aggregation provides a practical and rapid approach to evaluate the efficacy of gene correction of human diseases in mouse models.
    • Induction of a mature hepatocyte phenotype in adult liver derived progenitor cells by ectopic expression of transcription factors.

      Iacob, Razvan; Rüdrich, Urda; Rothe, Michael; Kirsch, Sarah; Maasoumy, Benjamin; Narain, Nidhi; Verfaillie, Catherine M; Sancho-Bru, Pau; Iken, Marcus; Popescu, Irinel; et al. (2011-05)
      By ectopic expression of a distinct combination of transcription factors we aimed to induce a mature hepatocyte phenotype in an adult liver derived progenitor cell population (ALDPC).