June 10, 2011
By C.J. Janovy
|Soumen Paul, PhD, assistant professor in KUMC's Department of Pathology and Laboratory Medicine|
Researchers at the University of Kansas Medical Center (KUMC) have made a groundbreaking discovery that could change the way stem cell research is conducted.
In a paper published this spring in the journal Stem Cells, Soumen Paul, PhD, an assistant professor in KUMC's Department of Pathology and Laboratory Medicine, reports that his lab has learned how to grow a population of "pluripotent" stem cells, which are critical to research that scientists hope will lead to treatments for diseases such as Parkinson's and Alzheimer's, spinal cord injuries, bone diseases and cancer.
Like embryonic stem cells, pluripotent stem cells have the ability to develop into all different cell types of the human body. This means they could be used to create an unlimited supply of cells, tissues, or even organs that could be transplanted to restore functions lost to disease and injury.
However, pluripotent stem cells tend to be unstable — they have a tendency to spontaneously differentiate into other cell types, such as those that go on to create blood, bone, nerve, heart or liver cells. For regenerative medicine, it's important to be able to grow a population of undifferentiated pluripotent stem cells that can be directed to become a specific cell type. However, it is extremely difficult to prevent pluripotent stem cells from differentiating spontaneously.
Working with mice, Paul discovered a new method for expanding a group of pluripotent stem cells while preventing them from differentiating. The method, which Paul described in "Self Renewal vs. Lineage Commitment of Embryonic Stem Cells: Protein Kinase C Signaling Shifts the Balance," prevents a group of proteins (called protein kinase C, or PKC) from signaling the stem cells to differentiate. When the PKC-signaling inhibitor is removed, these cells can then differentiate to all cell types.
"This creates an opportunity to increase the amount of pluripotent stem cells in a laboratory setting, so that they can be used as necessary for regenerative medicine purposes," Paul said. "Our method also allows pluripotent stem cells to be created from differentiated cells."
KUMC leaders say they are enormously proud of Paul's discovery. "A fundamental question in stem cell biology is how these cells make the choice between renewing themselves or differentiating into different types of cells. Dr. Paul's work has discovered one player in regulating this choice — the protein kinase C signaling pathway. Understanding the events controlling this choice will allow efficient reprogramming of cells," says Barbara Atkinson, MD, executive vice chancellor of the University of Kansas Medical Center.
If these results can be replicated in humans, Paul believes, the technology may ultimately be used to generate human cell types, thus bypassing the need for human embryonic stem cells in regenerative medicine.
While Paul has generated pluripotent stem cells in mammals, KUMC leaders cautioned policymakers not to conclude that human embryonic stem cell research is no longer necessary.
"We still don't know if these reprogrammed mouse cells truly hold the same potential," Atkinson said. "We recognize and respect that there are many differing opinions on how research should be conducted on stem cells. Just as a majority of Americans and Kansas believe stem cell research holds much promise and should be pursued, the University of Kansas Medical Center fosters the spirit of discovery that fuels scientific advancement in our nation. Dr. Paul's work is the result of good science, and good science thrives in a supportive environment."