Conditions for Tumor-free and Dopamine Neuron–enriched Grafts After Transplanting Human ES Cell–derived Neural Precursor Cells

• Published in: Molecular therapy 2009-10, Vol.17 (10), p.1761-1770
• Main Authors: Ko, Ji-Yun, Lee, Hyun-Seob, Park, Chang-Hwan, Koh, Hyun-Chul, Lee, Yong-Sung, Lee, Sang-Hun
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis - drug effects; bcl-X Protein - genetics; bcl-X Protein - physiology; Biochemistry; Brain-Derived Neurotrophic Factor - pharmacology; Cell Differentiation - drug effects; Cell Survival - drug effects; Cells; Cyclic AMP - pharmacology; Dopamine; Dopamine - metabolism; Embryonic Stem Cells - cytology; Embryonic Stem Cells - drug effects; Female; Genetic Vectors - genetics; Glial Cell Line-Derived Neurotrophic Factor - pharmacology; Growth factors; Hedgehog Proteins - genetics; Hedgehog Proteins - physiology; Humans; Immunohistochemistry; Medical schools; Medicine; Molecular biology; Neurons; Neurons - cytology; Neurons - drug effects; Original; Parkinson's disease; Polymerase Chain Reaction; Rats; Rats, Sprague-Dawley; Retroviridae - genetics; Tumors
• ISSN: 1525-0016; 1525-0024
• DOI: 10.1038/mt.2009.148

We have previously demonstrated derivation of neural precursor (NP) cells of a midbrain-type from human embryonic stem (hES) cells to yield an enriched population of dopamine (DA) neurons. These hES-derived NPs can be expanded in vitro through multiple passages without altering their DA neurogenic potential. Here, we studied two aspects of these hES-NP cells that are critical issues in cell therapeutic approaches for Parkinson's disease (PD): cell survival and tumorigenic potential. Neuroepithelial rosettes, a potentially tumorigenic structure, disappeared during hES-NP cell expansion in vitro. Although a minor population of cells positive for Oct3/4, a marker specific for undifferentiated hES cells, persisted in culture during hES-NP cell expansion, they could be completely eliminated by subculturing hES-NPs under differentiation-inducing conditions. Consistently, no tumors/teratomas are formed in rats grafted with multipassaged hES-NPs. However, extensively expanded hES-NP cells easily underwent cell death during differentiation in vitro and after transplantation in vivo. Transgenic expression of Bcl-XL and sonic hedgehog (SHH) completely overcame the cell survival problems without increasing tumor formation. These findings indicate that hES-NP cell expansion in conjunction with Bcl-XL+SHH transgene expression may provide a renewable and safe source of DA neurons for transplantation in PD.