Ph.D. Research Proposal - Influence of Reduced Oxygen Tension on Endoderm Germ Layer Differentiation of Mouse Embryonic Stem Cells
Date: April 19, 2012
Time: 1:30 PM
Location: New College Building, Room: 12-321
Pimchanok Mie Pimton
Advisor: Peter I. Lelkes, Ph.D.
If in vitro differentiation of embryonic stem (ES) cells is to be used for treating human diseases, including pulmonary hypoplasia and cystic fibrosis, it will likely require the derivation of large quantities of cells with high purity in defined condition. In this proposal, I propose to optimize an endodermal cell source for pulmonary tissue engineering. I will focus on directing the differentiation of mouse ES cells into definitive endoderm, as this first step is a prerequisite for efficient differentiation of more committed progenitor cells, and eventually mature, functional cells of endoderm-derived tissues such as lung epithelia. The proposed work toward this thesis seeks to demonstrate the feasibility of utilizing hypoxia to enhance differentiation of ES cells into definitive endoderm, which is relevant for liver, pancreas, stomach, intestine, and thymus, as well as the lung.
Most of the studies directed to enhance definitive endoderm differentiation of ES cells have focused primarily on using alternative soluble growth factors. However, little attention has been given to the possible effects that physical parameters in the microenvironment such as oxygen might have on the differentiation of the ES cells. In nature, ES cells develop in an environment characterized by reduced oxygen tension (hypoxia). Ironically, most ES cell manipulation in vitro has been performed under standard tissue culture conditions of 21% oxygen, which is far higher than what ES cells experience in vivo. Therefore, this study will assess the role of hypoxia on the differentiation of mouse ES cells, particularly towards definitive endoderm lineage. The results presented will show that hypoxia is capable of facilitating and enhancing definitive endoderm differentiation, indicated by an up-regulation of gene and protein markers associated with definitive endoderm, when compared to a matched differentiation condition under normoxia. Additionally, the mechanism of hypoxia-mediated up-regulation of endodermal markers, specifically that of HIF-mediated pathway, will be explored. Additionally, this work will also assess the competency of the hypoxia-mediated enhanced definitive endodermal cell to commit to the lung lineage. Preliminary data demonstrating the feasibility of applying hypoxia for ES cell differentiation will be proposed and its implications discussed.
The New College Building is located at 245 N. 15th Street (15th & Race), and can be reached from main campus via the Dragon Route shuttle that boards at 33rd and Market.