Electronic Thesis and Dissertation Repository


Master of Science




Dr. Cheryle Seguin

2nd Supervisor

Dr. David Hess

Joint Supervisor


Our lab previously demonstrated that expression of the lineage-determining transcription factor SOX17 in human embryonic stem cells was sufficient to specify stable definitive endoderm progenitors (DEPs). The current study was aimed at generating pancreatic precursors from SOX17-DEPs through controlled expression of the transcription factor NGN3. We generated hESC lines with inducible SOX17 and NGN3 and compared the effects of high and low levels of NGN3 expression. NGN3 expression in DEPs induced markers of pancreatic differentiation (PAX4, PAX6, NKX6.1, ISL1). While high NGN3 expression induced the β cell marker PDX1, low NGN3 expression induced the δ cell markers (CCKBR, somatostatin) within 12 days. We subsequently aimed to guide SOX17-NGN3 precursors to mature endocrine cells by culture in media pre-conditioned by multipotent stromal cells previously screened for islet regenerative capacity following transplantation in vivo. However, endocrine maturation was not observed. These findings demonstrate the precision required to direct β cell differentiation.