In most organs of the body, old cells are continually being replaced by new. If too many new cells are produced, however, it can lead to overgrowth and tumour formation. Too few cells, on the other hand, can result in organ degeneration. It is therefore crucial that exactly the right number of cells are produced.
As many serious disorders cause a reduction in the production of new cells, scientists are keen to develop drugs that stimulate the process, which in turn could help the body to cure itself.
It has long been known that the new cells are often formed by immature cells known as stem cells, but the mechanism regulating the number of new cells produced has remained something of a mystery. However, in a new study to be published by Cell stem-cell researcher Jonas Frisén has succeeded in showing how the body’s own stem cells do just this. Working alongside an American group of researchers, Professor Frisén and his team have identified a signal transduction process that regulates the degree of stem-cell division.
“Understanding how cell production is regulated increases our chances of producing drugs able to stimulate the endogenous production of new cells,” says Professor Frisén.
He hopes that the new findings can be used to develop drugs that stimulate, for example, the formation of new nerve cells to treat conditions such as stroke and Parkinson’s and skin cells to facilitate the healing of wounds. Professor Frisén is best known for his research on cerebral stem cells; the present study, however, has been carried out on stem cells in the intestine, one of the organs in the body with the highest rates of cell renewal.
“We also know that blood, brain and skin stem cells express the genes that we now know to be important in the intestine,” he says. “This suggests that the cell production mechanism can be the same for these stem cells too.”
The next step for Professor Frisén and his group is therefore to study how blood and skin stem cells go about producing new cells.
“EphB receptors coordinate migration and proliferation in the intestinal stem cell niche” by Johan Holmberg, Maria Genander, Michael M. Halford, Cecilia Annerén, Mariann Sondell, Michael J. Chumley, Robert A. Silvany, Mark Henkemeyer and Jonas Frisén
Cell 16 June 2006