Annotation and functional clustering of circRNA expression in rhesus macaque brain during aging

The abundance and function of circular RNAs (circRNAs) in mammalian brain have been reported, but their alterations in the biology of brain aging remain elusive. Here, using deep RNA profiling with linear RNA digestion by RNase R we explored a comprehensive map of changes in circRNA expression in rhesus macaque (macaca mulatta) brain in two age groups from adult (10？y) to aged (20？y) periods. Total 17,050 well expressed, stable circRNAs were identified. Cluster analysis reveals that dynamic changes in circRNA expression show the spatial-, sex- and age-biased specificities. On the basis of separate profiling of the RNAs, age-related circRNAs show differential correlation to host mRNA expression. Furthermore, two voltage-dependent L- and R-type calcium channel gene-derived circCACNA2D1 and circCACNA1E negatively regulate their host mRNA expression. Our results demonstrate the power of changes in circRNA expression to reveal insights into a potentially circRNA-mediated regulatory mechanism underlying the biology of brain aging