Date of Award


Degree Type


Degree Name

Master of Science




Dr. Dean H Betts


Induced pluripotent stem (iPS) cells have unparalleled potential for disease modeling and use in regenerative medicine but are plagued with genetic instability and tumourgenicity. Small molecules including histone deactylase inhibitors and DNA methylation inhibitors, as well as use of more undifferentiated cell types as source material, have been used to increase the efficiency and safety of reprogramming by necessitating fewer exogenous pluripotency factors. Human multi-lineage progenitor cells (hMLPCs), derived from post-partum umbilical cord blood, and human dermal fibroblasts (hDFs) were examined for both RNA expression and protein localization of pluripotency factors OCT4, SOX2, KLF4 and Nanog before and after 7-day treatment with s-adenosylhomocysteine (SAH), valproic acid (VPA), and basic fibroblast growth factor (bFGF). Untreated hMLPCs and hDFs expressed pluripotency factor mRNA but only KLF4 in hDFs, and KLF4/SOX2 in hMLPCs were detected at the protein level. SAH-treatment resulted in detection of Nanog protein in hMLPCs, solely in the presence of SOX2, without change in RNA transcript levels, indicating an important post- transcriptional role, which may act via the positive autoregulatory loop of OCT4, NANOG and SOX2 that is crucial for maintaining the undifferentiated state. Due in part to the synergistic autoregulatory relationships between endogenously expressed SOX2 and other pluripotency factors, hMLPCs may be more amenable to reprogramming.



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