A specific molecule that enables embryonic stem cells to differentiate into diverse cell types and thus to be pluripotent has been discovered by researchers of the Max Delbruck Center for Molecular Medicine (MDC) Berlin-Buch.
E-cadherin was up till now primarily known for its role in mediating cell-cell adhesion as a kind of "intracellular glue".
If E-cadherin is absent, the stem cells lose their pluripotency. The molecule also plays a crucial role in the reprogramming of somatic cells (body cells) into pluripotent stem cells.
Daniel Besser, Prof. Walter Birchmeier and Torben Redmer from the MDC, a member of the Helmholtz Association, used mouse embryonic fibroblasts (MEFs) in their stem cell experiments.
In a first step they showed that the pluripotency of these stem cells is directly associated with the cell-adhesion molecule E-cadherin. If E-cadherin is absent, the stem cells lose their pluripotency.
In a second step the researchers investigated what happens when somatic cells that normally neither have E-cadherin nor are pluripotent are reprogrammed into a pluripotent stem cell state.
In this reprogramming technique, somatic cells are converted into induced pluripotent stem cells (iPSCs).
The MDC researchers found that in contrast to the original cells, the new pluripotent cells derived from mouse connective tissue contained E-cadherin.
"Thus, we have double proof that E-cadherin is directly associated with stem-cell pluripotency. E-Cadherin is necessary for maintaining pluripotent stem cells and also for inducing the pluripotent state in the reprogramming of somatic cells," said Besser.
The findings were published online EMBO Journal 27 May 2011.