Gut bacteria-derived metabolite extends the lifespan of fruit flies

Gut bacteria can influence many aspects of host physiology, including metabolism and immunity. Metabolites produced by these bacteria can cross the intestinal lining and affect host tissues. Researchers at Kindai University and Kanazawa University in Japan sought to determine if specific gut bacterial metabolites could directly extend the lifespan of fruit flies.

Using a gnotobiotic fly model, they compared flies colonized with bacteria that could produce polyamines with those that lacked polyamine production. Polyamines like putrescine and spermidine are associated with improved biological functions and longer lifespans. Flies fed diets supplemented with these compounds lived significantly longer than those without polyamines.

When the flies were colonized with different E. coli strains capable of producing polyamines, those with the putrescine-producing bacteria lived longer than those with bacteria unable to produce polyamines. Male flies colonized with putrescine-producing strains lived 13.8 and 12.6 days, compared to 11.0 days for those colonized with non-producers.

In female flies, the effect was less consistent, with one strain extending lifespan to 14.9 days. The researchers found that changes in gene expression related to the immune and stress response pathways correlated with the lifespan differences. However, the exact mechanism by which these bacterial metabolites influence lifespan remains unclear.

This study demonstrates that gut bacteria-derived polyamines can impact host lifespan and provides a framework for investigating other microbiota-derived molecules.