Scripps Research Scientists Find Gene Expression Profile Shared by Pluripotent Stem Cells

Using a collection of about 150 human cell samples, the researchers created a database of global gene expression profiles using technology developed by Illumina, Inc. (San Diego). The team discovered that all of the pluripotent stem cell lines showed remarkable similarity in the analysis, while other cell types were more diverse. Further analysis revealed a protein-protein network common to pluripotent cells, pointing to what may be one of the key building blocks of the machinery that enables these transformative cells to differentiate into multiple cell types.

"Our results offer a new strategy for classifying stem cells by their molecular machinery," says Loring, who is director of the Center for Regenerative Medicine at Scripps Research. "We show that pluripotence and self-renewal are under tight control by specific molecular networks."

With rapid advances in the field of stem cells—including methods to induce pluripotence in once fully differentiated cell types, such as skin cells—the question of how to define pluripotence has become increasingly critical, especially for human cell lines, which cannot be treated as those from other species. Pluripotence in mouse cell lines, for example, has been defined experimentally, as the ability to give rise to the tissues of a mouse when injected into a mouse embryo.

"There has been no ethically acceptable equivalent test that could prove pluripotency in human cell preparations," said first author Franz-Josef Mueller, M.D., a visiting investigator at Scripps Research who is also affiliated with the Center for Psychiatry at the University Hospital Schleswig-Holstein, Campus Kiel, in Germany. "Many human cell preparations have been purported to be multi- or pluripotent, but there has been no practical way to define pluripotency in human cells."

The new Nature paper, however, may change this. The researchers dubbed the protein-protein network they identified as common to pluripotent stem cells "PluriNet,"

Origianl Research Article: Muller FJ et al Nature 2008 Aug 24 [Epub ahead of print]