Friday, August 19, 2005

Telomerase and Stem Cells

Via Instapundit.

By making mice grow furrier coats, researchers have discovered that an enzyme known to serve as a last-ditch defense against cancer also activates adult stem cells, which the body uses to repair its tissues.

The insight could lead to new treatments for certain diseases, possibly even promoting hair growth in animals other than mice.

The research, reported by Steven E. Artandi and colleagues at Stanford University in Nature today, shows that adult stem cells can be activated by an enzyme called telomerase.

The finding is surprising because telomerase is well known in a quite different context, protecting against tumors by limiting the number of times a cell can divide. The new findings put the enzyme astride two major biological pathways, one that promotes the growth of new cells for maintaining tissues and the other that prevents the excessive growth that leads to tumors.

Telomeres have previously been thought to play a role in aging. They are structures on a genetic level that seem to reduce with each successive generation. In other words, they may be the "timer" that determines how long a given cell will continue reproducing. Telomerase evidently is the enzyme that reduces telomeres. This newly discovered role (activating adult stem cells) may provide a solution to slowing or stopping aging at the cellular level.

When Dolly, the cloned sheep, was created, the scientists discovered that her cells' telomeres were lacking the length that an actual 'newborn' sheep has. This suggests that clones of adult cells inherit the length of telomere that the donor cell possesses at the time of donation. (Philip Dick may have been prescient in Blade Runner, otherwise known as "Do Androids Dream Of Electric Sheep?".)