Year 2

Our translation grant is intended to develop a safe and reliabel alternative to most stem cell based therapies. We have developed a large (>140) collection of purified embryonic progenitor cell lines that collectively, represent a wide swath of the biological diversity seen in human cells. Embryonic progenitor (EP) cell lines are derived from embryonic stem (ES)stem cells and represent cell lines that are mid-way between the pluripotent stem cells and fully differentiated adults cells. Our EP cell lines are clonally purified and thus display many advantages over ES cells in terms of commerical scale preparation and purification.

One of our primary study aims is to develop methods that will allow us to identify and isolate a specific EP cell type. One of the major challenges to accomplish this goal is to develop reagents and methods that can be used to purify a target EP cell line from the parental ES cell population from which it derived. For instance, we have identified several EP cell lines that can efficiently differentiate into cartilage producing cells. By assessing the protein markers that are expressed on the cell surface of these lines, we have developed a discrete collection of targets that can be used to develop affinity reagents(antibodies and peptides) that will allow us to purify these EP cell types from the parental ES cell populations. We have completed pilot experiments that show that antibodies to these cell surface targets can be used to efficiently purify EP cell lines from their ES source and plan in the final year of our studies to demonstrate this process for many additional EP cell types.

A second major aim of our study is to determine the overall biological diversity of our EP cell line collection. We have undertaken a large scale screen of these cell lines place under a broad range of differentiation conditions, including cell culture matrices, biological effectors and chemical inducers of differentiation. In the course of this activity, we have identified EP lines that effectively develop into cartilage, bone, nerves and fat. Further optimization of these differentiation regimens has allowed us to fine tune the process to produce products that can work effectively in animal-based models of human disease, such as cartilage deficit.

And finally, our research also aims to assess the ability to expand EP cell lines using methods and culture systems that are compatible with commercial production methods for cellular therapeutics. We have expanded EP cell lines for 20-30 doublings and have shown good stability of both the genome and biological capabilities of these lines. This, coupled with the clonal purity of the EP lines, can provide significant advantages with regards to the manufacturing of therapeutic products.