The key to a good neighbourhood is the people in it: it's made better by the (annoyingly cheery) do-gooder who brings in your parcels, or worse by the grouchy neighbour who lets their dog poop outside your door.
The same is true of your brain. That's according to a new study finding brain cells function like a community. These cells, it turns out, can actively create a nurturing environment that builds up the health and resilience of their cell neighbours. But some cells act as bad neighbours, spreading stress and damage.
Across your whole life, this community influences how your brain ages. Too many bad relationships may mean you age faster and experience issues like age-related memory loss as a result. However, a healthy brain community can work together to keep ageing at bay.
The researchers, from Stanford University in the US, think they may be able to use these new insights to develop treatments that could slow or even reverse ageing.
For the study, published in journal Nature, the team identified 17 cells that impact ageing, positively or negatively. They discovered that two of these had particularly powerful effects: T cells and neural cells – the bad neighbour and the good neighbour, if you will.
T cells, which usually help your body fight off infections, actually drive inflammation in the brain and so can accelerate ageing. On the other hand, neural stem cells (a rare type of unspecialised cell capable of developing into major cell types in the brain) have a powerful rejuvenating effect. We already knew that these cells are important for the maintenance and repair of our nervous systems, but the new study suggests these are key to creating the supportive environment our brain cells need to stay young.
To find this out, the researchers mapped the gene activity across 2.3 million cells in a mouse brain. They then used this model to build a ‘spatial ageing clock’, which uses machine learning to predict the biological age of individual cells. Usually, ageing clocks are used to estimate the overall biological age of an animal.
“For the first time, we can use ageing clocks as a tool to discover new biology,” said paper author and Stanford graduate student Eric Sun.
Next, the team hopes to start directly intervening in the relationships. “If we prevent T cells from releasing their pro-aging factors or enhance the effects of neural stem cells, how does that change the tissue over time?” asked Prof Anne Brunet, co-senior investigator of the study.
The researchers say the discovery could help us understand how diseases like Alzheimer’s, a type of dementia, change brain cells and accelerate ageing. But they also think it could reveal how we might be able to enhance the brain’s natural mechanisms of repair and resilience – and combat cognitive decline before it happens in the first place.
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