Chinese study sheds light on how proteins play a role in ageing process
- Protein called PAPPA found to be ‘common driver’ of ageing in many types of human cells, team says
- But it is triggered by signalling proteins called sirtuins, which are important for regulating metabolism
Increased levels of the protein were found to be a “common driver” of ageing in many types of human cells. But the researchers said this was actually triggered by a family of signalling proteins called sirtuins, which are important for regulating metabolism.
The finding could deepen understanding of the ageing process and help researchers find ways to intervene, according to the team from the Chinese Academy of Sciences’ Institute of Zoology and Beijing Institute of Genomics.
The researchers – led by Liu Guanghui and Qu Jing from the zoology institute and Zhang Weiqi from the genomics institute – reported their findings in the peer-reviewed journal Developmental Cell on March 13.
PAPPA, or pregnancy-associated plasma protein-A, is so named because it was first identified as one of four proteins found at high levels in the plasma of pregnant women – though its function was unknown for decades.
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In the latest study, levels of PAPPA were found to be significantly higher in the plasma of the elderly than in the young, “suggesting that this protein could serve as a potential biomarker for human ageing”.
Sirtuins, meanwhile, have been targeted by scientists investigating whether calorie restriction slows down ageing.
The academy noted in a statement that there had been few systematic comparative studies of the biological functions of PAPPA and sirtuins, and that it was not well understood how they worked together.
For the study, the team first looked at how sirtuins work. Using a technique called genome-targeted editing, they obtained human embryonic stem cells in which the seven sirtuins – known as SIRT1-7 – were separately removed. They found that a deficiency in any of the seven led to accelerated cellular ageing.
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The study also shed light on the process of ageing. When one of the seven sirtuins was missing, it gave PAPPA room to move and led to abnormal gene expression which then triggered cellular senescence – when cells stop dividing.
“This result provides new insights to elucidate the mechanism of human stem cell senescence and offers new clues and ideas for assessing and intervening in ageing,” according to the paper.
