The roundworm Caenorhabditis elegans is a commonly used model organism in the field of aging research. It develops from an egg to adult through four larval stages. These developmental stages are controlled by a developmental clock. Yidong Shen and colleagues working in the department of Director Adam Antebi used a laser to remove the germ cells.

They found that the remaining gonadal cells trigger production of a steroid hormone called dafachronic acid. Dafachronic acid activates so-called microRNAs, which work as tiny molecular switches causing changes in gene expression that promote longevity. Interestingly, this same steroid hormone-microRNA switch was previously shown by Antebi and colleagues to be part of the developmental clock. Thus, the loss of the germ cells ultimately causes the worm to use developmental timers to put in motion a life-prolonging programme.

In uncovering these findings, the Max Planck scientists have added some more pieces to the puzzle of describing and understanding how longevity is regulated. The question now is whether humans also possess a similar microRNA-controlled switch system.