A new study has revealed that more anti-inflammatory genes mean longer lifespan for mammals.
Humans 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 is known to help protect our cells from becoming inflammatory collateral damage, prompting researchers at the University of California, San Diego School of Medicine to ask whether CD33rSiglecs might help mammals live longer, too. 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.
Researcher Ajit Varki said that though not quite definitive, this finding is provocative, adding that 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. They also discovered that mice that were missing one CD33rSIGLEC gene and experienced inflammation early in life showed signs of accelerated aging (gray hair, disorientation, thin skin), had higher levels of reactive oxygen species and did not live as long as normal mice.
The higher CD33rSIGLEC gene number can be thought of as an improved maintenance system that co-evolved in mammals to buffer against the effects of many infectious episodes fought off by the immune system of long-lived mammals, said researcher Pascal Gagneux.
The study is published by eLife.
