My first car was my grandfather’s 1980 Chevrolet Malibu. For about two years before my family gave it to me, it sat unused in Grandpa’s garage—just enough time for all of the belts and hoses to rot and the battery to trickle down to nothing.
Why am I telling this story? Because it’s much like what happens to the DNA in our blood-forming stem cells as we age.
Hematopoietic stem cells (HSCs) spend very little of their lives in an active, cycling state. Much of the time they’re quiescent or dormant, keeping their molecular and metabolic processes dialed down. These quiet periods allow the cells to conserve resources, but also give time an opportunity to wear away at their genes.
“DNA damage doesn’t just arise from mistakes during replication,” explains Derrick Rossi, PhD, a stem cell biology researcher with Boston Children’s Hospital’s Program in Cellular and Molecular Medicine. “There are many ways for damage to occur during periods of inactivity, such as reactions with byproducts of our oxidative metabolism.”
The canonical view has been that HSCs always keep one eye open for DNA damage and repair it, even when dormant. But in a study recently published in Cell Stem Cell, Rossi and his team found evidence to the contrary—which might tell us something about age-related blood cancers and blood disorders. …