The longevity-promoting effect of moderate dietary restriction in roundworms could be due to the secretion of a protein that ultimately affects metabolism-regulating genes. This highlights the importance of neuroendocrine regulation in the ageing process and in treatments aimed at increasing longevity. 

From single-celled organisms to mammals, eating around 30 to 40% less than free-feeding levels leads to a longer life and thwarts age-related diseases. However, the reason for these benefits is unclear.  

Scientists are using the transparent, millimetre-long roundworm nematode Caenorhadbitis elegans as a model for deepening our knowledge about the biology of ageing. A recent study by researchers at the Massachusetts Institute of Technology in the US found a new mechanism by which C. elegans’ sensory perception of available food modulates the effect of dietary restriction on longevity.  

The research team focused on a small protein in C. elegans called DAF-7. They found that when the roundworm senses that food is limited, like during dietary restriction, a pair of sensory neurons secrete DAF-7. This activates the transcription factor DAF-16, the master regulator of a large number of genes related to oxidative stress and dauer (hibernation-like state). Moreover, since DAF-7 levels decrease with age, old roundworms do not respond to the longevity effect of dietary restriction, perhaps explaining why previous studies showed that older animals undergoing dietary restriction do not show life extension. 

The researchers conclude that, since their study suggests that roundworm response to food restriction could be modulated through specific neuroendocrine pathways, it is possible that drugs targeting similar pathways in mammals may be able to promote longevity when used together with dietary modifications. 

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