We age in part thanks to “friendly fire” from the immune system — inflammation and chemically active molecules called reactive oxygen species that help fight infection, but also wreak molecular havoc over time, contributing to frailty, disability and disease. The CD33rSiglec family of proteins are known to help protect our cells from becoming inflammatory collateral damage, prompting researchers at UC San Diego School of Medicine to ask whether CD33rSiglecs might help mammals live longer, too.
In a study published by eLife, the team reports a correlation between CD33rSIGLEC gene copy number and maximum lifespan across 14 mammalian species. In addition, they found that mice lacking one CD33rSIGLEC gene copy don’t live as long as normal mice, have higher levels of reactive oxygen species and experience more molecular damage.
“Though not quite definitive, this finding is provocative. As far as we know, it’s the first time lifespan has been correlated with simple gene copy number,” said Ajit Varki, Distinguished Professor of Medicine and Cellular and Molecular Medicine and member of the UC San Diego Moores Cancer Center. “Since people also vary in number of CD33rSIGLEC gene copies, it will be interesting to see if these genes influence variations in human lifespan as they do in mice.”