Identification Of Key Regulators Maintaining Stemness Of Murine Embryonic Stem Cells

Embryonic stem cells (ESC) are pleuripotent cells that can proliferate and differentiate with no limitation. They can differentiate into almost any type of cells of the organism. The isolation, culture, and successfully committed differentiation of ESC bring big hope for the organ transplantation on the base of cell engineering. Moreover, the study on regulation of ESC differentiation helps to learn the development and evolution of life. As so special pluripotent cells, the so called "stemness" refers the ability to maintain the pleuripotent to differentiating to other cells. And the sternness maintenance has always been the research focus of cell biology. In2012, The Nobel Prize for Physiology or Medicine was awarded jointly to the developmental biologist John B. Gurdon from England and Shinya Yamanaka from Japan for their outstanding contribution on the study of nucleus reprogramming. Their finding shows that the transcription factors, Oct4, Sox2, Klf4, c-myc are key regulators for maintaining sternness of ESC. However, ESC sternness maintenance is of much complication, whose detailed mechanism still largely unknown.Our research was undertaken to study the mechanism of ESC’s sternness maintenaning. Because murine ESCs are easy to culture and grow, we took murine ESC as the model to identify the proteomic change in the early stage of differentiation of mESC, and to find out the key proteins involving maintaining of sternness. LIF is the main additional factor for culturing mESC in vitro. mESC showed little but observable change in morphology ar7hours after withdrawing LIF, feeder cells and serum, we therefore harvested cells7hours after withdrawing the LIF, feeder cells and serum, and considered this timepoint as the early stage of ESC differentiation. With2D-PAGE-MS system, we identified the proteomic change during the early differentiation and got41proteins. We then selected some of them as candidates for further study. Western blotting analysis showed that the expression of Gpx-1markedly down-regulated in the early stage of ESC differentiation, which in accordance with the results of MS. Notably, the expression of Oct4and Nanog, the marker of ESC’s stemness, did not change much. Our preliminary data suggested that Gpx-1may play important roles in maintaining of ESC stemness, and provide a good clue to study further. There are13figures,3tables,49references...