"The current techniques to keep these cells alive are tedious and labor-intensive," said Ding. "Keeping the cells alive is so difficult that some people are discouraged from entering the field. It is very frustrating experience for everyone."
Mysteriously, mouse embryonic stem cellswhich share much basic biology with human embryonic stem cellsdo not pose the same difficulties in the laboratory. They can usually be split off from a colony and go on to survive and thrive.
To address these issues, the scientists decided to start with a screen of a library of chemical compounds to see if they could find any small molecules that could be added to the human embryonic stem cell culture that would promote the cells' survival.
When the scientists examined their results, they were elated to find two novel compounds (named Thiazovivin and Pyrintegrin) that both worked to dramatically protect the cells, promoting human embryonic stem cell survival by more than 30 fold.
"Basically, this solved this cell survival problem that has been plaguing scientists for more than 10 years," said Ding.
The Importance of Interaction
But the scientists didn't stop there.
Next, using the two new survival-promoting small molecules as clues, the scientists set out to understand the biological mechanism behind the cells' survival or demise. By examining cell growth in the presence and absence of the compounds, the team found that the key factor was a protein on the cell surface called e-cadherin, which mediates interactions among cells and between cells and the extracellular matrix (a structure present between a variety of animal cells that provides support and anchorage for cells and regulates intercellular communication).
"While in the past people have often talked about the proteins in cell nucleus as regulating stem cell function, our study puts the focus on a dif
|Contact: Keith McKeown|
Scripps Research Institute