Source: Cincinnati Children's Hospital Medical Center
Date: May 3, 2012
Summary:
Researchers have rejuvenated aged hematopoietic stem cells to be functionally younger, offering intriguing clues into how medicine might one day fend off some ailments of old age. Scientists at Cincinnati Children’s Hospital Medical Center and the Ulm University Medicine in Germany report their findings online May 3 in the journal Cell Stem Cell. The paper brings new perspective to what has been a life science controversy – countering what used to be broad consensus that the aging of hematopoietic stem cells (HSCs) was locked in by nature and not reversible by therapeutic intervention.
The findings are early and involve laboratory manipulation of mouse cells, so it remains to be seen what direct application they may have for humans. Still, the study expands what is known about the basic molecular and cellular mechanisms of aging -- a necessary step to one day designing rational approaches to aiding a healthy aging process.
One reason the research team focused on Cdc42 is that previous studies have reported elevated activity of the protein in various tissue types of older mice -- which have a natural life span of around two years. Also, elevated expression of Cdc42 has been found in immune system white blood cells in older humans.
In the current study, researchers found elevated activity of Cdc42 in the HSCs of older mice. They also were able to induce premature aging of HSCs in mice by genetically increasing Cdc42 activity in the cells. The aged cells lost structural organization and polarity, resulting in improper placement and spacing of components inside the cells. This disorganization contributed to the cells' decreased functional efficiency.
