On the afternoon of June 2, 2016, Dr. Pei Duanqing, the Director General of Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, joined SUSTech Lecture with a splendid lecture entitled Studies on Cell Fate and Its Application Prospect. This program was presided by Vice-President Wu Chuanyue.
As an expert in biomedicine, Dr. Pei Duanqing participated in the National High-tech R&D Program (863 Program) and the major research plan named Reproduction and Development of the Outline of the National Medium-and Long-Term Science and Technology Development. He also played an important role in gathering the expert group of Stem Cell Research in National Medium-and Long-Term Program, making great contribution to the studies on stem cells and cell regulation.
The Human body has approximately 100 trillion to 200 trillion cells. Studies on somatic cell reprogramming have enlightened us as to many ideas of exploring the rules and approaches with which cells can finally form our marvelous human bodies. Beginning with the status quo of the studies on stem cells, Dr. Pei Duanqing delivered an informative lecture on the stem cell with the studies and discovery patterns of cell fate as the theme.
One experiment, many findings
In the experiment of creating induced pluripotent stem cells, Dr. Pei brought three types of genes, namely Oct-4, Sox-2 and Klf-4 into four fibroblasts and then kept shooting them for eight consecutive days. During the process these fibroblasts first transformed into epithelial cells and then into pluripotent cells. Dr. Pei has drawn many conclusions from this experiment, one of which is that fibroblasts, after taking these three types of genes, must first transform into epithelial cells.
When exploring the mechanism of transformation, he found that it was Sox-2, Oct-4 and Myc that inhibited the signal transduction and deprived fibroblasts of their characteristics, and that Klf-4 could activate many relevant genes, endowing friboblasts with epithelial cells’ characteristics. In this way, these genes together made pluripotent cells finally come into being.
To improve experimental conditions for further research
However, the experiment has a low success rate, with only two or three successes out of ten attempts. On reflection, Dr. Pei owed this to the undesirable environment for reprogramming. Having attempted for many times, he found that when Tgfb content is too high, the experimental efficiency will be reduced. Conversely, the experimental efficiency will be improved when Tgfb inhibitor is added.
The phenomenon that experimental efficiency was improved ten percent when Vitamin C is added interested Dr. Pei and aroused his desire to explore the mechanism behind it. Vitamin C is normally taken as an anti-oxidant. In this experiment, it served as epigenetic conditions, a bridge for cells to avoid senescence and transform into pluripotent stem cells.
Uphill process similar to the downhill one
Reprogramming is an uphill process of converting a differentiated cell back into to a pluripotent stem cell. Is the downhill process from a pluripotent stem cell into a differentiated cell as same as the uphill one? In order to find the answer, Dr. Pei researched the cell differentiation model from pluripotent stem cells to hepatocytes.
At first, the subjects were epithelial cells, which, in three to five days, transformed into fibroblasts, and then on sixth or seventh day, they changed back into epithelial cells. This in-depth research proved that the process from pluripotent stem cells to differentiated cells entails the fibroblast phase. Dr. Pei noted that there remains a broad space for development to be explored in this field and he expected that more researchers would tap the potential and find out new rules, thus opening the door for other fields.
After the lecture, based on various questions raised by many students and teachers, Dr. Pei made a further discussion on cell fate.
