Abstract:
Adult neurogenesis is the continual generation of new neurons from neural stem
cells in brain regions such as the subgranular zone (SGZ) of the dentate gyrus in
the hippocampus. This genesis is important in learning and memory function,
which involve changing the strength of connections between neurons or
neuroplasticity. These fundamental and important features of the brain are known
to be promoted by exercise, which significantly alters the microenvironment of
the hippocampus and increases neurotrophic factors. In recent years, it has been
found that microRNAS (miRNAs), 21-23 nucleotide non-coding RNAs that post-
transcriptionally suppress mRNA activity, are abundantly expressed in the adult
brain and appear to regulate the maintenance of mature neural traits and synaptic
plasticity. In this study, 913 target genes of 37 adult rat hippocampal miRNAs
were computationally identified from the intersection of three prediction
algorithms: TargetScanS, Pictar and miRanda. These were then compared with
experimentally derived target genes that had differential expression after
voluntary exercise of adult rats from two studies, yielding 25 genes. Using
DAVID Functional Annotation Tool, the involvement of these 25 genes in
neurogenesis/neuroplasticity was elucidated. It was found from groups of
enriched GO terms with enrichment scores >1.3 that 18 out of the 25 target genes
were directly involved in neurogenesis/neuroplasticity. Also, the study shed light
on the possible role of the temporal expression of miRNAs on
neurogenesis/neuroplasticity. The identification and elucidation of the 18 genes
can lead to the promotion of good mental health and discovery of treatments for
mental illnesses and disorders.
