Forever Young: Reprogramming the Cellular Clock
New research reported this week in the journal Regenerative Medicine points to new directions for creating therapeutic stem cells from adult cells, a technique that has many possibilities for treatment of human diseases. Applying this technique may also lead to treatments directly applying to diseases of aging.
The paper (available here [PDF]) by authors from BioTime Inc., a California research company, demonstrates a new method that helps confirm the telomere hypothesis of cell aging. The telomere hypothesis suggests that a part of the chromosome called a telomere is the "clock" that counts the cell's age.
One of the problems that has plagued research into so-called "adult" stem cells is that while it's possible to make therapeutic stem cells from adult cells, these cells "act old." Unlike embryonic stem cells, they can't replicate as many times; they die out quickly.
Chromosomes are simply collections of DNA molecules that contain the "genetic code" used to build the proteins that become the body's tissues. A chromosome is really a sequence of codons, which are like the letters in a coded message, like a teletype message. Teletype operators end each message with a sequence of repeated "K" characters, like this:
THIS IS A TELETYPE MESSAGE. FOR YOUNGER READERS, A TELETYPE WAS LIKE TEXT MESSAGING EXCEPT IT PRINTED THE MESSAGES ON PAPER AND REQUIRED A KEYBOARD BIGGER THAN A BREADBOX.
The telomere is exactly like that series of K characters: it’s a repeated group of codons that ends the chromosome.