Research press release


Nature Aging

Ageing: Measuring ageing in naked mole rats

ハダカデバネズミ(Heterocephalus glaber)は、極めて長寿の齧歯類動物で、加齢しないように見える。しかし、分子レベルの加齢は確実に起こっており、それをエピジェネティック変化によって測定できることを報告する論文が、Nature Aging に掲載される。


今回、Steve Horvathたちの研究グループは、ハダカデバネズミ(0~26年齢)から採取した組織(11種類)の試料(約400点)を分析し、エピジェネティック変化の1つであるメチル化(自然に起こるDNAの化学修飾)を測定した。ヒトやその他の生物種において、DNAメチル化レベルと年齢が関連していることから、Horvathたちは、ハダカデバネズミに特異的なDNAメチル化の「時計」を上記の組織について作成し、メチル化レベルによって推定される年齢(メチル化年齢)が実年齢と非常によく相関することを明らかにした。Horvathたちは、雌の非繁殖個体のメチル化年齢と長寿の優位雌の繁殖個体(女王)のメチル化年齢を比較し、女王のメチル化年齢の加齢が非繁殖個体より遅いという観察結果を得た。


The naked mole rat — an exceptionally long-lived rodent that outwardly seems to defy ageing — does age on the molecular level, as measured by epigenetic changes, according to a new study in Nature Aging.

Naked mole rats (Heterocephalus glaber) have exceptional longevity for rodents of their size — with a maximum lifespan of 37 years — and are resistant to age-related diseases. Epigenetic changes — modifications that change gene expression but do not alter DNA itself — in naked mole rats have been linked to ageing. However, a robust epigenetic ‘clock’ of ageing based on these modifications has yet to be presented.

Steve Horvath and colleagues analysed almost 400 samples from 11 tissue types taken from naked mole rats aged between 0 and 26 years old to measure an epigenetic change known as methylation — a naturally occurring chemical modification of DNA. As levels of DNA methylation are associated with age in humans and other species, the team created naked mole rat-specific methylation ‘clocks’ across tissues, and found that methylation estimates of age correlate very well with chronological age. The authors compared the methylation ages of non-breeding females with those of the longer-lived, dominant breeding females (queens), observing that queens have slower methylation ageing than non-breeders.

The authors conclude that although observable characteristics of naked mole rats suggest that they are ‘non-ageing’ mammals, this species does age epigenetically — similarly to other mammals. The use of epigenetic clocks, they state, might not only allow the age of wild naked mole rats to be estimated, but also aid studies investigating their potential as a model organism for ageing, longevity and disease suppression.

doi: 10.1038/s43587-021-00152-1


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