Lentiviral vector-mediated gene delivery into human embryonic stem cells.

Human embryonic stem cells (hESCs) are pluripotent cells derived from the inner cell mass of preimplantation embryos. These cells can be cultured for long periods as undifferentiated cells and still retain their potential to give rise to cell types representing all three germinal layers. Given their unique properties, hESCs are expected to serve as an invaluable tool for basic and applied research. However, to exploit their remarkable potentials, the development of effective strategies for genetic modification of hESCs is required. Lentiviral-based vectors offer an attractive system for efficient gene delivery into hESCs. These vectors are derived from lentiviruses, a group of complex retroviruses that cause slow chronic immunodeficiency diseases in humans and animals. Gene delivery into hESCs by vectors derived from lentiviruses has the following advantages: (1) lentiviral vectors efficiently transduce hESCs; (2) they integrate into the host-cell genome, thus promoting stable transgene expression; (3) transgene expression is not significantly silenced in hESCs; and (4) transduced hESCs retain their self-renewal and pluripotent potential. In recent years, we and others have developed protocols for efficient transduction of hESCs by advanced modified replication-defective lentiviral-based vectors. Transduction of hESCs by these vectors resulted in high and stable transgene expression that was maintained over long periods of undifferentiated cultivation and after differentiation. This chapter focuses on methods for the use of lentiviral-based vectors for gene delivery into hESCs.