Patient-Specific Pluripotent Stem Cells for Hematologic Disease.

Abstract SCI-40

Pluripotent stem cells can be isolated from embryos (embryonic stem cells; ES cells) or generated by direct reprogramming of somatic cells (induced pluripotent stem cells; iPS cells). Both types can be differentiated into a multitude of cell lineages to serve disease research and cell replacement therapies. Additionally, genetically matched pluripotent stem cells generated via nuclear transfer (ntES cells), parthenogenesis (pES cells), or direct reprogramming (iPS cells) are a possible source of histocompatible cells and tissues for transplantation. We have used customized ntES cells to repair genetic immunodeficiency in mice (Rideout et al., Cell 2002); however, generation of ES cells by nuclear transfer remains inefficient, and to date has not been achieved with human cells. We have also generated ES cells with defined histocompatibility loci by direct parthenogenetic activation of the unfertilized oocyte (Kim et al., Science 2007). Compared to ES cell lines from fertilized embryos, pES cells display comparable in vitro hematopoietic activity, but appear compromised in repopulating hematopoiesis in irradiated adult mouse recipients. We are currently comparing the performance of ntES, pES, and iPS cells in murine models of thalassemia. We have generated human iPS cells by direct reprogramming of human somatic cells with OCT4, SOX2, MYC, and KLF4 (Park et al., Nature 2008), and have generated disease-specific iPS cells from patients with a number of hematologic conditions (Park et al., Cell 2008; Agarwal et al., submitted). Applications of disease-specific cells for investigating the mechanisms of reprogramming and for probing aspects of human bone marrow disorders will be discussed.