A team of researchers led by Michael Petrascheck who had previously found that administrating roundworm Caenorhabditis elegans with an antidepressant called mianserin increased their lifespan by 30-40 % attempted to find out how. Their new paper, published on eLife, could possibly shed light on how to extend young adulthood (instead of just increasing lifespan and end up with a longer dotage).
To determine how does mianserin extend life, the researchers gave thousands of worms either water or the antidepressant. Thereafter, they analysed the genetic activity throughout the ageing process of the worms.
Discovery of ageing-linked phenomenon of gene expression
The observations involved dramatic modifications in gene expression: groups of genes that would normally work in concert for the sake of the same function were found to exhibit changed expression in opposing directions – the newly-discovered phenomenon was named ‘transcriptional drift’. As the animal aged, gene expression appeared to become less and less coordinated.
As a matter of fact, this is not something uncommon to other species: the scientists confirmed the occurrence of ‘transcriptional drift’ in mammals as well when they probed further and examined data from mice and human brains.
First author Sunitha Rangaraju says that transcriptional drift might be used to measure changes characterised by ageing that start in young adulthood. This would constitute a new tool to study ageing.
Transcriptional drift delayed by mianserin
A yet more interesting finding is how treatment with mianserin at specific points in the lifetime
of the worms will suppress transcriptional drift.
10-day-old worms having received the antidepressant displayed gene expression featured in 3-day-olds. On the other hand, at 12 days old, the physiological changes needed for extending lifespan were complete and the drug no more generated the previous effect – it only affected lifespan positively during young adulthood, that is, old age was not extended, while youthful years were.
Mianserin would inhibit signals pertaining to the regulation of serotonin such that ageing-related physiological changes (like the transcriptional drift, and other processes) were delayed.
Since transcriptional drift also happens in mammals, could the same effects of the antidepressant be generated in them too? Petrascheck highlights the fact that their findings cannot answer this question. However, new doors have been opened: researchers can test whether the mianserin treatment comes with side effects, and whether it works differently on different organs.
Word of caution
It is to noted that the authors are not encouraging people to take the drug with the aim of extending their teenage or young adult years since worms and humans are very different, a point stressed by Petrascheck. Rather, their study suggests that a longer young adulthood might be a possibility.
Still, could we be closer to extending our own teenage and young adult years? Time will tell. Ah, time is but our limiting factor though.