Genome-wide analysis of hormonal systems important for human embryonic stem cell derivation

Funding Type: 
Comprehensive Grant
Grant Number: 
ICOC Funds Committed: 
Public Abstract: 

Mammalian development requires the differentiation of a single fertilized egg into more than 200 unique cell types in the body. Human embryonic stem cells (hESCs) are derived from preimplantation embryos and these cells can be cultured in the laboratory in an undifferentiated state while maintaining the potential to become almost any cell type the body may require. Although limited success has been achieved in generating hESCs, no therapeutic success in regenerative medicine has been reported. Earlier studies have indicated that embryos cultured as a group show superior growth and less cell death as compared to those cultured alone. These findings suggest that development of embryos is facilitated by hormonal factors, and that culturing multiple embryos in a small droplet maintained these secreted factors in sufficient concentration for optimal development. Indeed, several factors have been discovered to be secreted by embryos and exert their actions on embryonic cells. Our results further demonstrated that ovarian cells surrounding the eggs secrete hormones that are essential for the optimal development of eggs into early embryos. Although advances have been made to fertilize and culture human eggs for development into preimplantation embryos, only a small fraction of cultured eggs reach the preimplantation stage and the success ratio in hESC line derivation is poor. This low success is due primarily to the routine use of simple culture media lacking essential hormonal factors in which to culture human early embryos and to derive hESC lines from the inner cell mass of preimplantation embryos. We have identified hormonal factors secreted by ovarian cells surrounding the egg as well as those secreted by the embryonic cells themselves, and demonstrated their importance in the development of eggs into preimplantation embryos in mice. Using this animal model, we propose to formulate hormone-enriched culture media for in vitro fertilization and embryo cultures. Because these hormonal factors are likely to be essential for human embryo development, we will determine the presence of receptors for these hormonal factors in surplus blastocysts and zygotes donated by in vitro fertilization patients. After confirming the existence of key hormonal receptors in human embryos, we will thaw the surplus zygotes and 4- to 8-cell embryos and culture them in hormone-enriched media for development into preimplantation embryos. Once reaching the preimplantation stage, the inner cell mass of these embryos will be used to derive hESCs following culturing with selective hormonal factors. Our goal is to substantially increase the efficiency of the development of human eggs into preimplantation embryos and enhance success in hESC derivation. An added benefit of the present project would be improvement in the in vitro fertilization procedure for embryo transfer that is presently used for an estimated one million treatment cycles per year worldwide.

Statement of Benefit to California: 

The present application proposes to establish optimal conditions for efficient derivation of human embryonic stem cells. After identifying key ovarian paracrine and embryonic autocrine factors important for the derivation of human embryonic stem cells, it will be possible to formulate a hormone-enriched culture media for the routine generation of human embryonic stem cell lines. Future adaptation of this procedure for somatic cell nuclear transfer will allow the generation of patient-compatible embryonic stem cell lines. Because embryonic stem cells can be induced to differentiate into diverse cell types of the body, establishment of optimal culture conditions for the derivation of these cells would benefit medical research and allow new treatment modalities for diverse degenerative diseases.
We will submit patent applications on our findings to protect intellectual property rights according to {REDACTED} guidelines. In addition to application in embryonic stem cell fields, the present findings also are expected to substantially improve the success rate of in vitro fertilization procedures that are presently used for an estimated one million treatment cycles per year worldwide. We anticipate that successful completion of the present proposal could benefit patients with degenerative diseases and infertility in California and throughout the world. The P.I. currently has a patent application pending on the use of brain-derived neurotrophic factor in the promotion of early embryo development which is provisionally licensed by a pharmaceutical company. We expect future findings will lead to similar patent applications and licensing agreements that would benefit the State of California.