Comprehensive analysis of hippocampal miRNAomes in humans and mice

Aim: This study aims to explore the similarity and difference of hippocampal miRNAomes between humans and mice. Materials & methods: A systematic comparison of the miRNAomes between healthy human and mouse hippocampi was performed using high-throughput sequencing followed by bioinformatic analyses. Results: A novel miRNA termed novel-21-5p and a human-specific miR-656-3p were identified in human hippocampi, which were expressed ubiquitously and predicted to be associated with neural activities. Compared with mouse, abundantly expressed miRNAs in human hippocampus were notably enriched in pathways pertaining to neural activities, such as neurotrophin TRK receptor signaling pathway, axon guidance and synaptic transmission. Expression pattern of orthologous miRNAs between human and mouse hippocampi was conserved. Meanwhile, the expression conservation was positively correlated with the sequence conservation. Conclusion: Hippocampal miRNAomes between humans and mice were overall comparable; the differences in expression or function across species should be considered when constructing mouse models.