Discovering novel microRNAs and age-related nonlinear changes in rat brains using deep sequencing

Elucidating the molecular mechanisms of brain aging remains a significant challenge for biogerontologists. The discovery of gene regulation by microRNAs (miRNAs) has added a new dimension for examining this process; however, the full complement of miRNAs involved in brain aging is still not known. In this study, miRNA profiles of young, adult, and old rats were obtained to evaluate molecular changes during aging. High-throughput deep sequencing revealed 547 known and 171 candidate novel miRNAs that were differentially expressed among groups. Unexpectedly, miRNA expression did not decline progressively with advancing age; moreover, genes targeted by age-associated miRNAs were predicted to be involved in biological processes linked to aging and neurodegenerative diseases. These findings provide novel insight into the molecular mechanisms underlying brain aging and a resource for future studies on age-related brain disorders.