Human Sperm Have Hidden ‘Aging Clocks
- Increasing paternal age has been linked to elevated health risks for the next generation, including higher risks of obesity and stillbirth.
- Most research into this link focuses on how the DNA inside sperm changes with age.
- New research from University of Utah Health has shown that the RNA contents of sperm go through similar shifts over time in both mice and humans, potentially leading...
Scientists have discovered a hidden RNA “aging clock” in human sperm.
Increasing paternal age has been linked to elevated health risks for the next generation, including higher risks of obesity and stillbirth. But what drives this increased risk remains unknown.
Most research into this link focuses on how the DNA inside sperm changes with age. However, sperm carries other molecules as well, including a diverse array of molecules called RNAs.
New research from University of Utah Health has shown that the RNA contents of sperm go through similar shifts over time in both mice and humans, potentially leading to a rapid, dramatic shift at mid-life.
“Old RNA” seems to change cells’ metabolism-potentially contributing to the health risks of having kids later in life.
The results appear in the EMBO Journal.
‘Seeing’ the hidden world of sperm RNA
Previous work in Chen’s lab had established that RNA in sperm could be changed by a father’s surroundings, including diet, and that those changes could effect the next generation. But the kinds of RNA molecules that seemed to be most important were tough to detect with standard techniques. Chen’s team developed an advanced RNA sequencing method, called PANDORA-seq, to “see” this previously undetectable world of sperm RNAs.
When they used this new tool to analyze sperm in mice, the researchers spotted a pattern that customary techniques couldn’t detect-a sharp, dramatic transition in sperm RNA contents in mice between 50 and 70 weeks of age. Along with this “aging cliff,” they found what appeared to be a molecular clock.
As males age, the proportions of certain sperm RNAs change progressively-longer fragments become more common, while s