miRNAs mediate propagation of stress-induced behavioural changes to offspring

Experience-induced behavioral changes in mice may be passed down to the next generation via alterations induced in non-coding micro-RNA molecules (miRNA), reports a paper published online this week in Nature Neuroscience.

It is known that male mice exposed to stress early in life exhibit reduced ‘anxiety-like’ behavior and this can be passed down to their offspring. However, the mechanism by which this occurs was unknown.

Isabelle Mansuy and colleagues exposed male mice to neonatal trauma and found that this caused changes in the expression of several miRNAs in both the brain and sperm of these mice. The authors also show that if they inject RNA from a stressed mouse into an embryo fertilized by an unstressed male, the resulting offspring also exhibit the behavioral changes observed in the stressed males.

Although it is not clear how stress induces changes to miRNA levels in the sperm, these results provide preliminary insight into the mechanism by which environmental experience can be translated into a molecular signal, which can then be transmitted to progeny, and potentially lead to behavioral alterations in those offspring that do not depend on changes to the genome.