CircRNAs are a recently appreciated class of RNAs generated by backsplicing (Li et al., 2018). Most characterized circRNAs are produced from exons of protein-coding genes (Zhang et al., 2014).CircRNAs lack free ends, resulting in greater resistance to exoribonuclease digestion compared to their linear RNA counterparts (Jeck et al., 2013). Interestingly, circRNAs were found to accumulate in the brains of Drosophila and rodents during aging (Gruner et al., 2016;