UC San Diego

Human pluripotent stem (hPS) cells revolutionized tissue engineering with their ability to indefinitely self-renew whilst retaining the potential to differentiate into all mature cell types of the human body. However, the use of hPS cells in regenerative medicine is hindered by contamination with unwanted cell types, which includes undifferentiated cells capable of forming tumors upon transplantation. In addition, differentiated cell populations are often impure and contain cell types derived from multiple lineages. To overcome these problems requires a complete understanding of differentiation conditions so that hPS cell derivatives are restricted to a single lineage. In addition, to advance the use of hPS cells in regenerative medicine it would be desirable to develop derivative expandable cell populations with restricted differentiation potential. Here I describe a systematic approach to identify conditions that support the derivation and propagation of cell populations associated with specific developmental lineages. Specifically, I will describe approaches to derive and expand multipotent progenitors with either endodermal or mesodermal properties. Employing hPS reporter lines, I based self-renewal of endodermal or mesodermal cells on proliferative capacity and maintenance of gene markers specific to each lineage. Iterative protein screens using a high throughput screening approach referred to as Arrayed Cellular Microenvironments (ACME) identified a fully defined and optimized culture condition that supports the derivation and propagation of a homogenous progenitor cell population with mesodermal properties. This study presents a framework for defining the culture requirements for expanding progenitor populations derived from hPS cells