Background: The emerging concept is that microRNAs (miRNAs) play a central role in controlling stem cell self-renewal and fate determination by regulating the expression of stem cell regulators. miR-125b, one of neuronal miRNAs, recently was found to be necessary for neural differentiation of neural stem/progenitor cells (NS/PCs). However, the other specific biological role of miR-125b in NS/PCs is little known. We used rat NS/PCs as a model system to study the role of miR-125b in governing the behavior of NS/PCs.
Results: We report here the transfection of exogenous miR-125b inhibited proliferation of NS/PCs but promoted differentiation and migration. Whereas anti-miR-125b had the opposite effect. Similar results were observed when Nestin was knocked down by siRNA. Subsequently, we demonstrated that Nestin was a direct functional target of miR-125b. MiR-125b downregulates the expression of luciferase through Nestin 3'untranslated region (3'-UTR), and the regulation was abolished by mutations in the miR-125b binding site. MiR-125b targeted the 3'-UTR of Nestin and reduced the abundance of Nestin at both mRNA and protein levels.
Conclusion: The results provided new insight into the function by which miR-125b modulates NS/PCs proliferation, differentiation and migration. The data also indicated the regulatory role of miR-125b in NS/PCs might through the suppression of Nestin expression.