Of mice, men and embryonic stem cells

Penn researchers may have found a way to untangle the mire which is the embryonic stem cell controversy. Professor of Animal Biology Hans R. Schöler and his team of researchers have identified a receptor, the germ cell nuclear factor or GCNF, that could lead to new ways of creating embryonic stem cells.

Stem cells are valuable because they have the potential to form a number of different tissues and consequently be used to treat various conditions, such as generating new nerve cells for spinal cord injuries.

While stem cells are located throughout the body, embryonic stem cells have a greater potential for generating different cell types than adult stem cells. But embryonic stem cell research poses an ethical dilemma because the cells are obtained through the destruction of human embryos, which some view as human life.

The discovery of GCNF may help resolve this ethical debate. In experiments involving mice, Schöler, who is from the school of Veterinary Medicine, found that GCNF plays a key role in restricting embryonic stem cells’ pluripotency or their ability to develop into many different adult cell types. If researchers can learn how GCNF shuts down genes, then they can also possibly discover how to reverse that process, thereby regaining pluripotency.

The aim, Schöler said, is to learn how to turn back the clock on cellular development, to convert ordinary adult stem cells back into embryonic stem cells.

Schöler stresses that while GCNF successfully removes pluripotency, it is only one of several mechanisms, the others still unknown, that do so.

Still, GCNF’s effects are considerable. It has the ability to repress Oct4, the only known gene that is essential for pluripotency.

“GCNF is part of a machinery that sets a mark,” said Schöler. “Since we know what kind of mark it’s setting, we can erase this memory which will help push back the cells.”

That Schöler’s research may help quiet the ethical debates is clear.

“You’re not destroying embryos. That’s the most important issue,” he said. “You are taking cells from your own body [and] putting them back [into an embryonic stem cell state]. This would not be generating embryos at any stage. People know that it’s not possible to generate embryos from embryonic stem cells.”

Still, Schöler is not immune to the controversy. His research is currently limited to mice.

“We’re not very happy about this situation because you are developing something in the mouse, [which is], OK, great for the mouse, but you really want to have something which is beneficial for humans,” he said. “I feel like for the first time in my life I can do something for humans.”

Originally published on January 24, 2002