Researchers at Texas Tech University and the University of Wisconsin have discovered two proteins that control potassium regulation in stem cells found in the embryonic brain of rats.
Understanding this potassium regulation and how these proteins work can help researchers develop better detection and treatment methods for diseases of nervous system and the heart, said Dean O. Smith, PhD, (pictured), vice president for research at Texas Tech.
Since these stem cells had not yet developed specialized properties of nerve or muscle cells, the potassium regulated by these proteins is probably required for the stem cell to divide, Smith said.
"These voltage-gated, potassium-channel proteins are vitally important in the brain and in muscle, including the heart," Smith said. "If we can understand how and when they develop in stem cells as they change into nerve and muscle cells, then we can open the door to further exploitation of this knowledge in the detection and treatment of diseases that include Alzheimer’s, Parkinson’s, and cardiovascular diseases, just to name a few."
All cells, including stem cells, need potassium to divide, Smith said. When grown, muscle and nerve cells require potassium to contract and to relay information throughout the brain. The availability of this potassium is highly regulated in mature cells, and disruption can lead to serious health disorders. Therefore, scientists want to understand this regulatory mechanism and learn when it appears in the developing embryo.
"We kind of discovered these proteins by accident," Smith said. "Originally, we intended to make these stem cells differentiate into nerve cells that might then be suitable for transplanting into another animal to repair brain damage. To be sure the cells had differentiated, we examined the potassium channels that are normally found in mature nerve cells. As a control, we did the same tests on undifferentiated stem cells expecting not to find them. But, to our surprise, they too had the same potassium channels."
Other tests indicated that these stem cells were clearly not differentiated into nerve cells and could not function as such, Smith said. Therefore, these potassium channels must play some other role in stem cells development.
"We’re not sure what yet," he said. "But we think it might relate to cell replication. These two proteins are found in all mammals, and similar ones are found in animals such as fruit flies and frogs.”
Illustration: Texas Tech University.
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Abstract (Public Library of Science ONE 3(2), (02/13/08))