Assessing efficacy and safety of retro- and lentiviruses as gene therapy vectors in human embryonic stem cells
Embryonic stem cells (ESCs) are derived from the inner cell contents of the pre-implanted embryo. These nascent cells not only can divide and perpetuate themselves (self-renewal) but are also capable of generating almost every body cell type, including muscle, heart, skin, bone, and brain cells. Because of these special properties, human ESCs (hESCs) offer the possibility of treating various human diseases, and can serve as an invaluable experimental model to study early events in human developmental biology. Many potential applications involving hESCs require reproducible and safe methods for delivering genes. A gene delivery vehicle that is based upon retroviruses represents the most efficient strategy to stably introduce therapeutic genes into hESCs. However, this process currently involves insertion of the gene randomly at many possible sites within the host cell genome. A chance insertion into regulatory or coding region of an important host gene may have significant consequences to hES or hES-derived cells, and thus the effects of insertion site location in hESCs need to be fully investigated. Our broad, long-term objective is to access the efficacy and safety of using retroviruses as gene delivery vehicles in hESCs. The Specific Aims of this proposal are (i) to perform a comprehensive, genome-wide analysis of insertion sites for retroviral gene delivery vehicles in hESCs, and (ii) to determine the role of insertion site location upon the activity of the introduced gene and the onversion of hESCs to more mature cell types.
Understanding the insertion site preference of retroviral vectors in hESCs is critical for evaluating the efficacy and safety of using these vectors for diagnostic and therapeutic purposes. The above information gained from the proposed study may reveal retroviral factors and host conditions that can affect insertion site selection, and thus guide strategies for engineering retroviral vectors that can safely and effectively manipulate the hESC.
Because of human embryonic stem cells’ (hESCs) special properties to self-perpetuate and to mature to form any cell type, hESCs offer the possibility of treating various human diseases. Many potential diagnostic and therapeutic applications for hESCs require genetic manipulation of hESCs using retroviral vectors. The proposed study is aimed at investigating, and ultimately improving the safety and efficacy of delivering genes into hESCs by retroviral vectors, an important consideration in successfully bringing stem cell treatments to a clinical setting. The study will therefore benefit the State of California in terms of lowering health costs and in treating its citizens who suffer from a wide range of different diseases, including stroke and heart disease, diabetes, cancer, neurological disorders, burns, autoimmune disease, muscular dystrophy, and AIDS.